Journal of East China Normal University(Natural Science)

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Normal families of meromorphic functions and omitted functions

YANG Qi, YANG Jinhua

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 1-6. DOI: 10.3969/j.issn.1000-5641.201811043

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In this paper, we study the normal criterion of meromorphic functions concerning omitted functions. By using P-Z lemma and the method of proof by contradiction, we obtain a new normal criterion: if the zeros of the families of meromorphic functions are all have multiplicity at least 3, then the families of meromorphic functions concerning omitted functions are normal.

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Analysis and application of exponential degradation paths with random failure thresholds

GUAN Qiang, FU Zhiliang

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 7-15. DOI: 10.3969/j.issn.1000-5641.201811040

Abstract （386）

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In a classical degradation experiment, the performance of a product is reduced or raised to a certain threshold value, which is regarded as a product failure; this is often refereed to as single-point degradation. Although this definition is widely used, it is not sufficiently comprehensive and cannot be used alone to describe the full product degradation process. In this study, we improve the single-point degradation model and propose the interval degradation model; in this context, the previously fixed threshold value will be generalized to a random value at a specified interval. We discuss the lifetime distributions for a variety of interval degradation models when the degradation path is an exponential function. Numerical integration and Monte Carlo simulation are used to calculate the lifetime distribution for interval degradation models and single-point degradation models; in addition, we determine the relationship between the respective models. The simulation results reveal that the performance of the interval degradation model is more reasonable and effective than that of single-point degradation model.

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The polar form of hyperbolic commutative quaternions

KONG Xiangqiang

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 16-23. DOI: 10.3969/j.issn.1000-5641.201911001

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Firstly, this paper presents the e₁-e₂ representation and matrix representation of hyperbolic commutative quaternions. Secondly, the polar form theorem of hyperbolic commutative quaternion is presented; the existence and uniqueness of the respective polar form are proven, and a series of properties for the hyperbolic commutative quaternion polar form are obtained. Lastly, the relationship between the polar form, e₁-e₂ representation and matrix representation of hyperbolic commutative quaternions are discussed. Hence, the paper provides a theoretical basis for further research on the application of hyperbolic commutative quaternions.

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An algorithm for finding all polynomial solutions of nonlinear difference equations

Jiangtao YU, Yinping LIU

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 24-39. DOI: 10.3969/j.issn.1000-5641.201811037

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Difference equations are a major aspect of computer algebra; yet, there are currently few studies on solving general nonlinear difference equations. Inspired by the homogeneous balance principle that works well for solving nonlinear differential equations, we use it to find polynomial solutions for a wide range of nonlinear difference equations, in which a new n-order expansion method is proposed to process the powerless cases of the homogeneous balance principle. They are combined together as an algorithm that can be used to find all polynomial solutions of nonlinear difference equations. The algorithm is implemented in Maple, and the experiments show that it is effective and efficient.

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I-convexity and Q-convexity of Orlicz-Bochner function spaces with the Luxemburg norm

DONG Xiaoli, GONG Wanzhong

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 40-50. DOI: 10.3969/j.issn.1000-5641.201811042

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There are some equivalent definitions for I-convexity and Q-convexity. In this context, if (Ω, Σ, μ) is a finite measure space, the Orlicz-Bochner function space L_(M)(μ, X) endowed with the Luxemburg norm is I-convex if and only if M ∈ △₂(∞) ∩ ▽₂(∞) and X is I-convex; similarly, L_(M)(μ, X) is Q-convex if and only if M ∈ △₂(∞) ∩ ▽₂(∞) and X is Q-convex.

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Topological graph passwords based on the gracefulness of disconnected graphs with circles

MU Yarong, LIU Xinsheng, YAO Bing

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 51-57. DOI: 10.3969/j.issn.1000-5641.201811045

Abstract （353）

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Graph labeling is an important branch of graph theory. We use disconnected graphs to start our study, and show that disconnected graphs G = (C₄, K_r)∪∪_t=1^kK_m,n^t and G = (C₄, K_r)∪K_1,n∪∪_t=1^kT^t allow graceful labelings. Algorithms can be used to provide a theoretical basis for proving the application of disconnected graphs to networks.

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Atomic distortion in CrN: A first-principle investigation

WANG Qianqian, ZHAO Zhenjie, LI Xin, XIE Wenhui

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 58-66. DOI: 10.3969/j.issn.1000-5641.201922002

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First principle calculations indicate that Cr and N atoms in the orthorhombic phase of CrN (Chromium Nitride) tend to shift from their ideal positions along the [100] direction. This shift can induce zigzag Cr-N-Cr chains in the orthorhombic phase; these atomic distortions have not been taken into account in previous studies. The atomic distortions may decrease the total energy of the orthorhombic phase by 0.125 eV/formula unit and make the structure more stable. Lattice constants, moreover, may also be in better agreement with experiment results when considering these atomic distortions. Further, the bulk modulus K₀ decreases significantly when considering the atomic distortions and is closer to the experimental value. The atomic distortions are induced by the asymmetric magnetic forces between asymmetric magnetic layers in the special antiferromagnetic order of the orthorhombic phase, which compensates for the magnetic forces between the layers. The atomic distortions would not change the Mott-insulator property of the orthorhombic phase but may reduce the band gap slightly.

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Study on the covariant chiral effective field theory of vector meson

WANG Yan, YANG Jifeng

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 67-75. DOI: 10.3969/j.issn.1000-5641.201922007

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In this paper, we employ covariant chiral effective field theory to explore the prescriptions in the loops involving spin 1 vector fields. The self-energy diagram for a Goldstone boson containing a vector meson line is studied, and consistent results are obtained in two representations of the vector field. Our calculation shows that the EOMS^[1](Extended On-Mass Shell) proposed indeed removes the terms that violate chiral power counting. Closer examination, however, shows that the problematic sources are actually localized; thus, we propose a simpler EMS (extended MS) cheme, which is further validated using a vertex diagram. Compared to EOMS, this scheme eliminates the localized terms that violate chiral power counting without additional manipulation or modification of the non-local terms. This feature would bring about better convergence of the chiral expansion and is more suitable for studying heavy hadrons with chiral effective theory.

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The complexity of Kerr-AdS black holes

DING Yuchen, WANG Tao

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 76-82. DOI: 10.3969/j.issn.1000-5641.201922004

Abstract （386）

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Gauge/gravity duality has shed light on physics research. It reveals that conformal field theory on the boundary is equivalent to the bulk of anti-de Sitter space-time, which brings us great convenience for studying the conformal field on the boundary. Recently, Susskind et al. proposed a conjecture for complexity/action duality, which states that the quantum computational complexity of the boundary state of a black hole is equivalent to the action in a Wheeler-DeWitt patch. The complexity represents the difficulty of performing quantum computing, which means that black holes may be linked to quantum computing. This provides us with deeper insights on black holes. Based on this conjecture and taking the contribution of null joints into consideration, we improve the original method of Susskind et al., and recalculate the action growth rate of the Wheeler-DeWitt patch of Kerr-AdS black holes more accurately. Finally, we get the complexity of the state on the boundary of Kerr-AdS black hole space-time.

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Novel polymer semiconductor films and related field effect transistor devices

YE Jianchun, ZHOU Lizhao, LI Wenwu, OU-YANG Wei

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 83-92. DOI: 10.3969/j.issn.1000-5641.201922006

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Thin films using a novel organic polymer semiconductor (DPPTTT(poly(3,6-di(2-thien-5-yl)-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione) thieno [3,2-b] thiophene)) were prepared by a solution process and characterized through different techniques. It was found that the thickness, surface roughness, and Raman peak strength of the semiconductor films changed with the solution concentration and rotation rate. The polymer semiconductor was used to prepare the active layer for p-type organic field effect transistors; with these, the influence of channel length on critical transistor parameters (i.e., carrier mobility and threshold voltage) was studied. It was found that the effective carrier mobility was the highest at 0.12 cm²/Vs when the channel length was reduced to 50 μm. With a decrease in channel length, both carrier mobility and threshold voltage tended to increase, which was contrary to the short channel effect. This paper may provide new perspectives for better understanding the physics of field effect transistor devices.

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Application of TiO₂ nanotube arrays for bipolar photocatalytic fuel cells

WANG Jianqiao, LIU dong, ZHOU Jun, XI Qinghua, NIE Er, SUN Zhuo

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 93-102. DOI: 10.3969/j.issn.1000-5641.201922005

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Photocatalytic fuel cell (PFC) technology is a combination of photocatalytic technology and fuel cell technology, which can degrade wastewater and generate electricity at the same time. The influence of the preparation process for photoanodes of TiO₂ Nanotube Arrays (TNAs) on its morphology and structure was explored; a positive correlation between the electrolysis time and the tube length of TNAs was confirmed by a Field Emission Scanning Electron Microscope (FESEM). We can combine TNAs with Cu₂O photoelectrodes to obtain a system with stronger photocatalytic activity, confirming the existence of a PFC synergistic effect. The optimal electrolysis process was 4 h, and the photocatalytic degradation rate of the electrode prepared by this process was more than 79% within 2 h. Analysis of the three standards showed an excellent linear correlation between the photocurrent of PFC and the chemical oxygen demand (COD); as the degradation proceeds, the mass transfer process is reduced and the correlation between the two is weakened.

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Performance of lime-based algae control in urban landscape water

ZHOU Yunchang, HE Yan, CHEN Jinghan, HUANG Minsheng

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 103-109. DOI: 10.3969/j.issn.1000-5641.201831012

Abstract （341）

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In this research, we studied the effect of lime dosages on algae control as well as the dynamic changes in nitrogen and phosphorus nutrients in urban landscape water based on the growth and decline of algae blooms at Guhua Park in Shanghai. The results showed clear seasonal variations in algae biomass in Guhua Park. The growth of algae could be inhibited by the addition of lime, and the inhibition performance improved with increases in lime dosage. Specifically, the algal inhibition rate ranged from 20% to 46% when the applied lime dosage increased from 0.02 g/L to 0.2 g/L. When the lime dosage increased from 0.2 g/L to 0.5 g/L, however, there was no significant increase in inhibition efficiency observed. Therefore, considering both algal inhibition efficiency and economic cost, the optimum dosage of lime is 0.2 g/L. Meanwhile, nitrogen and phosphorus nutrients in water initially increased and then decreased, reaching a final dynamic equilibrium. This study offers a new approach for algae control of urban landscape water.

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Health assessment of transboundary rivers based on the PSR and matter-element extension models: A case study of Taipu River

XIE Yihan, LI Gen, YANG Mengjie, CHU Xiaoye

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 110-122. DOI: 10.3969/j.issn.1000-5641.201831013

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Taking Taipu River as an example, a multi-index assessment system for the water body and riparian zone is constructed based on the PSR model. Index weights are calculated with the entropy weight method, and the Taipu River is evaluated using the PSR and matter-element extension models. The results show that the Wujiang segment is classified as “high pressure-good state-low response ability”, the Jiashan segment is classified as “low pressure-medium state-low response ability”, and Qingpu segment is classified as “low pressure-medium state-high response ability”. The result of the health assessment of Wujiang is Grade Ⅲ (poor). Meanwhile, Jiashan and Qingpu are both Grade Ⅱ (medium), but leaning towards Grade I (good); this indicates that although the current health status of the river is medium, the health status of the water source area could be gradually restored by further increasing protection of the water source given that the policy is to some extent already effective. The results can provide decision support for river management and ecological construction of the riparian zone in Taipu River.

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Journal of East China Normal University(Natural Science) 2020, 2020 (1): 123-125. DOI: 10.3969/j.issn.1000-5641.202049001

Abstract （291）

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Analysis of water and sediment characteristics in the main tributaries of the Yangtze River and their associated influence factors

WANG Zhengcheng, MAO Haitao, SHEN Jiwei, TANG Xin, CHEN Xiang

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 126-138. DOI: 10.3969/j.issn.1000-5641.201841031

Abstract （458）

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Water and sediment characteristics of Yalong River, Minjiang River, Jialing River, and Wujiang River are one of the defining aspects of variation in Yangtze River sediment; they have influence on the operation of the Three Gorges Reservoir, which is related to utilization of water resources in the Yangtze River Valley and equilibrium of the water ecosystem. This article is based on hydrological and sediment monitoring data from 2002—2016 of four important hydrological control stations set up in the main tributaries of the Yangtze River, which are Tongzilin, Gaochang, Beibei, and Wulong. Variation characteristics of hydrology and sediment parameters and their associated influence factors were studied systematically; correlations between hydrological and sediment parameters were subsequently analyzed by SPSS. The results showed that over time: the annual average sediment concentration, annual sediment load, and modulus of sediment transport of the tributaries of the Yangtze River decreased 22.57%~91.54%; the annual runoff of Yalong River, Minjiang River, and Wujiang River increased 3.28%~17.96%, but that of Jialing River decreased 1.58%; and the median size of sediment of the Jialing and Wujiang Rivers increased 50%~80%. Furthermore, cascade hydro power stations were built, which led to annual average sediment concentration, annual sediment load, median size of sediment, and modulus of sediment transport to decrease by 5%~79.34%. Natural disasters such us heavy rainfall, landslide, collapse, debris flow, dam-break, landslide under artificial conditions, and dumping earth rock into a river lead to annual average sediment concentration, annual sediment load, and modulus of sediment transport to increase by 20%~702.94%. Correlations between the parameters ranked from strong to weak are: annual average sediment concentration and annual sediment load/annual average sediment transport modulus, annual runoff and annual average sediment concentration, annual runoff and annual sediment load/annual average sediment transport modulus, annual average sediment concentration and median size of sediment, median size of sediment and annual sediment load/annual average sediment transport modulus, and annual runoff and median size of sediment. The research results will provide theoretical support for the planning and design of cascade hydropower stations in tributaries of the Yangtze River as well as operation of the Three Gorges Reservoir.

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Water transfer plan for the Ecological Restoration Project Area in Chongming Dongtan National Nature Reserve

LU Peiyi, ZHU Jianrong, YUAN Lin, TIAN Bo, PAN Jialin

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 139-149. DOI: 10.3969/j.issn.1000-5641.201841035

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The Ecological Restoration Project Area in Chongming Dongtan National Nature Reserve is located in the East Asian-Australasian Flyway. Different bird species have their own unique requirements for habitat water depth. Water depths for bird habitats can be managed via habitat blocks; the blocks are divided based on the feeding characteristics and spatial distributions of the respective target bird species. Accordingly, the key to effective water depth management is to maintain a suitable water depth in each block. For internal habitat blocks in the southern C zone of the Ecological Restoration Project Area, when a block’s water depth is greater than the maximum critical depth, water is drained to the Suitang River, which sits outside the blocks and inside the coastal levee. Conversely, when the water depth decreases below the minimum critical depth, water is drawn from the Suitang River into the habitat blocks through the sluice gate from the outer Chongming Dongtan. Water level variations in the habitat blocks and the Suitang River and changes in mean water depth of each block are calculated according to water balance principles. These principles take into consideration evaporation, precipitation, plant evapotranspiration, and soil infiltration; moreover, the time and amount of water drained from the habitat blocks or the water drawn from the outer Chongming eastern shoal were also calculated and analyzed. The research results enable a scientific water replenishment plan for ecological water regulation at Chongming Dongtan National Nature Reserve and guidance for building favorable habitats for migratory birds.

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Spatiotemporal variations and influencing factors of organic carbon content in the urban rivers of Shanghai

ZHU Kun, WU Ying, Qi Lijun

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 150-158. DOI: 10.3969/j.issn.1000-5641.201841032

Abstract （406）

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Surface water samples were collected monthly from four sites in Suzhou River and Huangpu River from December 2015 to December 2016. We analyzed the concentration of dissolved organic carbon (DOC) and particulate organic carbon (POC) along with total suspended matter (TSM) and stable carbon isotope (δ¹³C) to understand the spatial and temporal variations in Suzhou River and Huangpu River. During the dry season, the DOC concentration of upstream sections of Suzhou River (4.52 ±0.48 mg·L^-1) was higher than the downstream sections (3.66 ±0.32 mg·L^-1), while there was no significant difference between the upstream and downstream sections during the flood season. Different retention times for DOC transportation for the upstream sections relative to the downstream sections might be a major factor for the spatial distribution of DOC. The δ¹³C (-29.1‰ ±1.0‰) during the flood season was more negative than the dry season (-28.1‰ ±0.6‰), indicating the significant contribution from plankton in the flood season. The mass fraction of POC (POC%) showed no significant differences between the flood and dry seasons, but the POC% in the dry season (6.01% ±2.27%) was still higher than the flood season (4.10% ±0.99%). The DOC concentration and POC% in Huangpu River showed no obvious differences the upstream and downstream sections; however, DOC showed higher concentration during the winter and lower concentration during the summer. The lower TSM (79.1 ±26.4 mg·L^-1) and more negative δ¹³C (-28.1‰ ±0.9‰) in the flood season suggested that the Huangpu River was affected mainly by the water discharge from Taihu Lake during the flood season; POC% in the flood season was higher than the dry season. DOC was the dominant fraction of organic carbon in the two rivers, and the difference in the water self-purification capacity between two urban rivers resulted in the difference of DOC/POC variation range. The gradual decrease in the DOC concentration of the Huangpu River during the period from 2005-2016 indicates that the third phase of sewage treatment projects achieved initial effectiveness in controlling organic pollution of the Huangpu River, but the high concentration of total organic carbon (TOC) indicates that the organic pollution in Huangpu River was still at a relative high level.

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Review of estuarine and coastal environmental monitoring technologies

GU Jinghua, GE Zhenpeng, WANG Jie

Journal of East China Normal University(Natural Science) 2020, 2020 (1): 159-170. DOI: 10.3969/j.issn.1000-5641.201841037

Abstract （515）

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Estuaries and coasts are the most sensitive zones in land-sea interaction-these zones have now become the core of earth system science research. In recent years, estuarine and coastal environments are facing serious challenges from rises in both sea level and high-intensity human activities. Strengthening the capacity of estuarine coastal environmental monitoring technology is essential for understanding the process and change mechanisms of the estuarine and coastal environments and improving our prediction of future changes. In this paper, monitoring elements, methods, common instruments, and equipment for estuarine and coastal monitoring are discussed holistically based on five aspects: meteorology, hydrology, topography, geology, and environment. Given the uniqueness of estuarine and coastal locations, we show that current monitoring of extreme weather and long time series data is particularly inadequate and needs to be improved holistically.

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Property of the consistent Fredholm index and property (ω₁)

DAI Lei

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 1-7. DOI: 10.3969/j.issn.1000-5641.201911004

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In this paper, a new spectrum is defined according to the property of the consistent Fredholm index. We establish the sufficient and necessary conditions for a bounded linear operator defined on a Hilbert space that satisfies the property (ω₁). In addition, the paper explores the relationship between the property (ω₁) and hypercyclic operators (or supercyclic operators). Meanwhile, new conditions for hypercyclic operators and supercyclic operators are given.

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Rigidity of submanifolds with parallel mean curvature in a hyperbolic space

ZHOU Jundong

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 8-14. DOI: 10.3969/j.issn.1000-5641.201911009

Abstract （379）

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Let M be a complete submanifold with parallel mean curvature in a hyperbolic space and Φ be the traceless second fundamental form of M. In this paper, it is shown that the submanifold is totally umbilical if the L² norm of |Φ| has less than quadratic growth on any geodesic ball of M and either sup_{x∈_M}|Φ|²(x) is less than some constant or Lⁿ norm of |Φ| is less than some constant. This is a generalization of the results on complete minimal submanifolds.

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Lie group analysis and exact solutions for a class of population balance equations

LIN Fubiao, ZHANG Qianhong

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 15-22. DOI: 10.3969/j.issn.1000-5641.201911008

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In this paper, exact solutions for a class of population balance equations were investigated. The population balance equation was first transformed to a partial differential equation; symmetries of the partial differential equation were then obtained by use of the classical Lie group analysis method. In addition, the paper presents symmetries, optimal system of subalgebras, reduced ordinary differential integral equations, and group invariant solutions of the population balance equation. Exact solutions of the reduced ordinary differential integral equations were subsequently found using trial functions. Finally, exact solutions for a class of population balance equations are derived.

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Internal layers for a singularly perturbed differential equation with Robin boundary value condition

CHAIKOVSKII Dmitrii, Mingkang NI

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 23-34. DOI: 10.3969/j.issn.1000-5641.201911043

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In this paper, we consider a second order singularly perturbed equation with a discontinuous right-hand function and Robin boundary value condition. Applying the boundary layer function method, we can construct an asymptotical approximation of the solution. We also prove the existence of the solution and obtain an estimation of the remainder based on the matching method.

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The Orlicz space equipped with the Φ-Amemiya norm contains an order asymptotically isometric copy of c₀

CUI Yun'an, AN Lili

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 35-40. DOI: 10.3969/j.issn.1000-5641.201911007

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In Orlicz space, a new norm that is equivalent to the Luxemburg norm is introduced. It is called the Φ-Amemiya norm: ${\left\| x \right\|_{\Phi ,{\Phi _1}}} = \inf \left\{ {\frac{1}{k}\left( {1 + \Phi \left( {{{ I}_{{\Phi _1}}}\left( {kx} \right)} \right)} \right)} \right\}$. It is shown, furthermore, that the Orlicz function space equipped with this norm $\left\{ {{L_{\Phi ,{\Phi _{\rm{1}}}}},{{\left\| \cdot \right\|}_{\Phi ,{\Phi _1}}}} \right\}$ is a Banach space. Hence, this paper demonstrates the conditions for the Orlicz space with the Φ-Amemiya norm to contain an asymptotically isometric copy of c₀.

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Optimal conditions for the existence of positive solutions to periodic boundary value problems with second order difference equations

WANG Jingjing, LU Yanqiong

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 41-49. DOI: 10.3969/j.issn.1000-5641.201811039

Abstract （357）

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By using the fixed-point index theory of cone mapping, we show the optimal conditions for the existence of positive solutions for second order discrete periodic boundary value problems
$\left\{ {\begin{array}{*{20}{l}} {\Delta^2 y(n-1)+a(n)y(n)=g(n)f(y(n)),}&{n\in[1,N]_{\mathbb{Z}},}\\ {y(0)=y(N), \;\;\;\Delta y(0)=\Delta y(N)}&{} \end{array}} \right.$
with vanishing Green’s function, where $[1,N]_{\mathbb{Z}}=\{1,2,\cdot\cdot\cdot, $$N\},\,f:[1,N]_{\mathbb{Z}}\times\mathbb{R}^+\rightarrow\mathbb{R}^+$ is continuous, $a: [1,N]_{\mathbb{Z}}\rightarrow(0,+\infty),$ and $\mathop {\max }\limits_{n \in {{[1,N]}_{\mathbb{Z}}}} a(n)\leqslant4\sin^2(\frac\pi{2N}),\,g\in C([1,N]_{\mathbb{Z}},\mathbb{R}^+), $$\mathbb{R}^+:=[0,\infty)$.

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Blow-up of solutions for nonlocal diffusion equations with a weighted gradient reaction

WANG Suzhen, MENG Haixia

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 50-54. DOI: 10.3969/j.issn.1000-5641.201911006

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This paper considers the blow-up phenomena of solutions for nonlocal diffusion equations with a weighted gradient reaction, and gives the sufficient conditions for existence and blow-up. Firstly, the local existence of solutions is proven by using the Banach fixed-point theorem. Secondly, a new auxiliary function is constructed by using eigenfunctions. Finally, the results are combined with the differential inequality technique to obtain the upper bound of the blow-up time.

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Non-sequential double ionization of argon in counterrotating circularly polarized two-color laser fields

QIAN Lijie, YANG Yan, SUN Zhenrong

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 55-63. DOI: 10.3969/j.issn.1000-5641.201922010

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In this paper, the non-sequential double ionization (NSDI) process of Ar in 800 nm and 400 nm counterrotating circularly polarized two-color(CRTC) laser fields was studied using the classical ensemble model. The dependence of the non-sequential double ionization mechanism and quantum yield on laser intensity, laser intensity ratio, relative phase, and pulse duration of two pulses is calculated and analyzed in detail. The energy evolution of two electrons in the time domain is obtained and two different non-sequential double ionization mechanisms are revealed. The influence of the electron collision energy for different non-sequential double ionization processes is also discussed.

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Electrostatic curved mirror of cold molecules

LI Jing, YANG Zhenghai, HOU Shunyong, WEI Bin, LIN Qinning, YANG Tao, YIN Jianping

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 64-69. DOI: 10.3969/j.issn.1000-5641.201922014

Abstract （346）

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As one of the most important optical instruments, molecular (atomic) reflecting mirrors have been broadly applied in experiments for trapping, loading, and guiding of molecules (atoms); however, given that the mirrors can only change the velocity of particles in the longitudinal direction, there is no focusing capability in the lateral direction and particles can subsequently diverge. Using ND₃ as an example, we propose a compact micro electrostatic curved mirror to address this issue; we show via theoretical calculations and Monte-Carlo simulations that the proposed mirror can both direct a beam of molecules and achieve transverse bunching of molecules. This kind of reflecting mirror can be used in an extensive range of optical applications for manipulating or loading molecules, composing molecular cavities, and so forth.

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Spin density of tightly focused hybrid-order Poincaré beams

SUN Hong, DONG Guangjiong

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 70-75. DOI: 10.3969/j.issn.1000-5641.201922012

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Research on spin of Poincaré beams not only has practical engineering applications, but is also important for understanding the nature of light. In this paper, we study the spin density of the tightly focused hybrid-order Poincaré beams (TFPB) and find that it has both longitudinal and transverse components. Unlike tightly focused full Poincaré beams whose longitudinal spin density is on average zero, the total longitudinal spin density of tightly focused hybrid-order Poincaré beams is not zero. The spin density of TFPB has rich controllable spatial patterns; in particular, the longitudinal spin density can be either a ring shape or a regular polygon. These features can be used to separate chiral particles or to manipulate dynamics of ultracold spinot gases.

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Optical dispersion of Bose-Einstein condensates

LIAO Yujiao, DONG Guangjiong

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 76-82. DOI: 10.3969/j.issn.1000-5641.201922013

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Recent studies have shown that Bose-Einstein condensates (BEC) can act like quantum dielectric materials, which react to light fields, and thus co-manipulation of light-matter waves is possible. So far, the dispersion properties of BEC for optical fields with a large degree of detuning have not been investigated. Accordingly, in this paper, we analytically obtain formulas for the first- and second-order dispersion. Our numerical calculation shows that the refractive index and the second-order dispersion coefficient depend on the properties of red or blue detuning. In the case of red detuning, the refractive index is greater than 1 and the second-order dispersion is normal dispersion. In the case of blue detuning, the refractive index is less than 1 and the second-order dispersion is anomalous dispersion. The second-order dispersion coefficient changes dramatically with changes in detuning. When the detuning quantity is on the order of GHz, the BEC can function as a strong dispersion medium. The first-order dispersion is independent with red detuning or blue detuning; as the amount of detuning increases, the first-order dispersion decreases and the corresponding group velocity increases. Our research shows that BEC is a new dispersion medium for manipulating ultrashort pulse light.

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Lorentz symmetry violation and accelerated expansion of the universe

ZHAI Hanyu, XUE Xun

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 83-89. DOI: 10.3969/j.issn.1000-5641.201922011

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The supernova observations of 1998 show that the universe is accelerating and expanding. Dark energy refers to the cosmic content of the universe's accelerated expansion. The positive cosmological constant Λ is an important factor for dark energy, but the cause of the accelerated expansion of the universe is not Λ. Lorentz invariance is the most accurate symmetry in nature, but all quantum gravitational theories predict the breakup of Lorentz symmetry. Based on the cosmological model of a large-scale Lorentz violation(LSLV), the Friedmann equation modified by effective gravitational theory is discussed and the effect of a large-scale Lorentz violation combined with a cosmological constant term can produce the observed acceleration of the universe.

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A study of nucleon-nucleon scattering in covariant chiral effective field theory at the two-loop level

SUN Jin, YANG Jifeng

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 90-97. DOI: 10.3969/j.issn.1000-5641.201922008

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The amplitude of the two-loop level in N-N(nucleon-nucleon) scattering is calculated using covariant chiral effective theory. Based on the skeleton of the box diagram, the two-loop diagram results from the correction of pion self-energy. Two subtraction schemes will be employed for comparison: $\overline {{\rm{MS}}}$ and ${\rm{E}}\overline {{\rm{MS}}}$. The loop amplitude obtained with $\overline {{\rm{MS}}}$ contains terms that violate chiral power counting rules; with ${\rm{E}}\overline {{\rm{MS}}}$, the results are entirely chiral contributions with the exception of non-local “anomalous” ones that must be retained.

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Species composition and distribution pattern of weed communities in Chongqing metropolis

WU Xue, HUANG Li, JIN Cheng, QIAN Shenhua, YANG Yongchuan

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 98-109. DOI: 10.3969/j.issn.1000-5641.201931002

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We arranged 86 1 km×1 km vegetation surveying plots in Chongqing metropolis using the grid method. The plots were used to investigate the species composition and distribution pattern of weed communities in the context of rapid urbanization. The findings of the study were as follows: ① 301 weed species belonging to 223 genera and 69 families were recorded. Among the recorded species, species of the Compositae and Gramineae were the most abundant; ② Annual weeds and dwarf weeds were the dominant types of weed species; ③ The weed communities in Chongqing metropolis were primarily comprised of native species. There were 31 exotic weed species and 11 invasive weed species recorded in the study; ④ The similarities in weed species composition across high-, medium- and low-urbanization areas were low. Additionally, the composition of dominant species within the weed community varied by area; ⑤ Urbanization had impacted weed biodiversity, evidenced by the lower number of weed species and the Shannon-Wiener diversity index in the high urbanization areas compared to that of the medium and low urbanization areas; ⑥ The number of weed species in the 86 sample plots showed a polycentric pattern with increasing distance between the survey plot and city center. Overall, urbanization had a significant impact on the composition and diversity of weed communities in mountainous multi-center cities, but the urbanization gradient of weed species is different from that of plain single-center cities.

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Interspecies associations and species-habitat associations in the evergreen broad-leaved forest of Tiantong National Forest Park, Zhejiang

YANG Qingsong, LIU Heming, ZHU Tongtong, ZHANG Shouhe, WANG Xihua

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 110-119. DOI: 10.3969/j.issn.1000-5641.201931004

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The objective of this study was to clarify the relationship between interspecies associations and species habitat preferences in Tiantong National Forest Park. A total of 109 species of 20 hm² evergreen broad-leaved forest plots were selected and tested for interspecies associations and species-habitat associations. The results indicated that: ① the ratio of species pairs with significant associations increased with spatial scale and the ratio of negative associations was higher than positive; ② 89.9% of species were significantly correlated with at least one habitat variable, including 73.4% of species positively and 65.1% of species negatively correlated with habitats; ③ at scales larger than 20 m, the results of interspecies associations were consistent with those of species pair habitat preferences; but at smaller scales (i.e., < 5 m), most species pairs did not show significant interspecies associations, indicating there are not habitat preferences but rather other ecological processes influencing interspecies association patterns. The results provide a theoretical basis for further understanding the mechanism of species coexistence in evergreen broad-leaved forests.

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Preparation and application of crosslinked polyvinyl alcohol in electrosorption

CHEN Ling, MAO Shudi, ZHANG Yi, LI Zhe, PIAO Xianqing, SUN Zhuo, ZHAO Ran

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 120-130. DOI: 10.3969/j.issn.1000-5641.201931003

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Sulfosuccinic acid (SSA) can be used as a crosslinking agent and a donor of a hydrophilic group when fabricating a cation exchange membrane. In this study, SSA was crosslinked with polyvinyl alcohol to form a cation exchange membrane for a capacitive deionization system. In this study, the impact of manufacturing parameters (i.e., crosslinker content, crosslinking temperature) on the deionization performance of a composite membrane were investigated in detail. A comparison was made between a capacitive deionization system (CDI) without an ion exchange membrane and a membrane capacitive deionization system (MCDI) coated with a PVA/SSA layer. The results show that the adsorption capacity and charge efficiency can be enhanced by 15% and 25%, respectively, with the PVA/SSA membrane layer; furthermore, the optimal mass fraction of SSA is 5%, and the optimal crosslinking temperature is 100 ℃.

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Preparation and fluorescence detection properties of ZnO nanostructure based on microdroplets

HUANG Binbing, XIE Yan, XIE Wenhui, ZHAO Zhenjie, LI Xin

Journal of East China Normal University(Natural Science) 2020, 2020 (2): 131-139. DOI: 10.3969/j.issn.1000-5641.201933001

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In this paper, we discuss ZnO nanostructures synthesized by a hydrothermal method in a droplet microreactor. The microfluidic chip used integrates a multi-function unit that includes a T-channel for droplet formation, a Y-channel for droplet fusion, and an S-channel for rapid mixing and observation of the nanoparticle formation process. By adjusting the flow rates of the aqueous phase and the oil phase, we studied the morphology and size of droplets; fluorescence detection of the ZnO nanostructure synthesized, moreover, was evaluated by an FITC-labeled goat anti-bovine IgG. This work shows that ZnO nanostructures can be prepared by fluid dynamic coupling of droplets and that the morphology and size of the nanostructures vary with droplet size. When the flow rates of the oil phase, ammonia water, and ferric solution were 600, 30, and 90 μL/h, respectively, the ZnO nanostructure synthesized at 75 ℃ showed optimal fluorescence detection performance.

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Contents

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 0-0.

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A discussion on the diversion process of tide-dominated estuary bifurcation: The North Branch estuary of the Yangtze River

LU Jiayu, GE Jianzhong, DING Pingxing

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 1-12. DOI: 10.3969/j.issn.1000-5641.201941015

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The North Branch estuary of the Yangtze River is a typical tide-dominated estuary with bifurcation. The hydrodynamics and diversion processes are the major factors in sediment transport and geomorphology evolution of the tide-dominated estuary. This paper is based on data from the bottom tripod system and a cross-section survey of the North Branch in April 2018, whereby the dominant flow of each channel is calculated. The results show that during the spring tide cycle, the Santiao Port and the Guyuansha south waterway are flood-dominated and the net tidal current flows landward, whereas the Guyuansha north waterway is ebb-dominated, and the net flow has a seaward direction. Moreover, a high-resolution numerical FVCOM model is used to simulate the diversion process of the North Branch estuary. The results suggest that: the cross-sectional area of Guyuansha south waterway is much bigger than that of the north waterway, and the propagation direction of the lateral tide is consistent with the orientation of the Guyuansha south waterway, which mainly has onshore movement through the Guyuansha south waterway. The spatial distribution of the flood tide flow is significantly uneven in these two waterways. Meanwhile, tidal current from the Guyuansha south waterway crosses the shallow shoal and reaches the north waterway. It produces a net flow with the seaward direction through the north waterway. The flood-tide and ebb-tide diversion ratio of the Guyuansha north waterway are 29.7% and 47.2%, respectively, during the spring tide period and 41.6% and 43.1%, respectively, during the neap tide period. The residual patterns indicate that the tidal current enters the estuary from the south waterway and exits through the north waterway. These indicators and diversion characteristics can help predict estuarine sediment transport and geomorphological evolution processes within an individual bifurcated channel.

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Numerical simulation of saltwater intrusion mitigation by building a sluice in the North Branch of the Changjiang Estuary

ZHU Jianrong, LU Peiyi, TANG Chuanmin, CHEN Qing, Lü Hanghang

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 13-22. DOI: 10.3969/j.issn.1000-5641.201941017

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The most prominent feature of saltwater intrusion in the Changjiang Estuary is the saltwater spillover from the North Branch into the South Branch during the dry season; the spillover is the only source of saltwater for the Dongfengxisha, Taicang, and Chenhang Reservoirs as well as the main source of saltwater for the Qingcaosha Reservoir. A three dimensional numerical saltwater intrusion model, validated on the Changjiang Estuary, was applied to simulate and analyze salinity variation both during and after construction of the sluice at the upper reaches of the North Branch; the model considered tide, climatic river discharge, and wind in January and February. The simulated results showed that the South Branch is occupied by freshwater, the phenomenon of saltwater spillover from the North Branch vanishes and the salinity in the upper reaches of the North Branch decreases substantially after building the sluice. The salinity at the water intakes of the Dongfengxisha, Taicang, and Chenhang Reservoirs approaches 0. The salinity at the water intake of the Qingcaosha Reservoir decreases significantly and is less than 0.45 and there is freshwater at all time. The operation of the sluice in the numerical experiments is adopted in two ways. One is open during ebb current, closed during flood current in the daytime, and open during flood current in the nighttime. The other is open during ebb current and closed during flood current in the daytime and nighttime. The salinity variations in the South Branch with the two operational schemes are nearly identical. This can be attributed to the fact that the saltwater intrusion in the upper reaches of the North Branch is substantially reduced by the former sluice operational scheme, and a freshwater area with salinity approaching 0.45 appears. Even though the sluice is open during day flood current, the water entering the South Branch is freshwater and the total seaward residual current in the South Branch is enhanced. Considering the numerical simulation results and operation costs, the former sluice operational scheme is recommended. The water intake time is significantly improved, not only for the Dongfengxisha, Chenhang, and Qingcaosha Reservoirs in Shanghai, but also for the Taicang Reservoir in Jiangsu; moreover, security in water supply is ensured for both places.

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Influence of water level rise on currents and saltwater intrusion in the Changjiang Estuary

TANG Chuanmin, ZHU Jianrong

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 23-31. DOI: 10.3969/j.issn.1000-5641.201941001

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A semi-implicit estuarine, coastal, and ocean model (ECOM-si) was used to simulate and analyze the influence of a rise in water level on runoff, tidal and wind-driven currents, and on current and saltwater intrusion under the combined effects of various dynamic factors. In a scenario where the water level rises 30 cm in the Changjiang Estuary, numerical simulation results show that seaward runoff decreases due to augmentation of the river transection area; tidal currents decrease slightly with increases in water depth; the wind-driven current by northerly winds in the dry season is enhanced, which flow landward in the North Channel and seaward in the South Channel forming horizontal circulation; and the wind-driven current in the North Branch is strengthened. After the water level rise, saltwater intrusion in the North Branch is enhanced; salinity changes slightly in the middle reaches of the South Branch; the most distinct areas of saltwater intrusion enhancement are in the North Channel and North Passage, where the salinity rise is greater than 1 in neap tide and is somewhat reduced in spring tide; the salinity rise in the northern outlet of the North Channel reaches the maximum value observed in the entire estuary; and salinity on the shoal at the river mouth of the South Passage reduces because the water level rises and the nonlinear effect weakens. The water level rise, moreover, results in a salinity increase at the water intake of the three reservoirs (Qingcaosha, Chenhang, and Dongfengxisha) in the water source of the South Branch, which reduces water intake time and affects the safety of the water supply.

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Impact of the South-to-North Water Diversion Project on saltwater intrusion and freshwater resources in the Changjiang Estuary

SU Aiping, Lü Hanghang, WU Yufan

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 32-42. DOI: 10.3969/j.issn.1000-5641.201941031

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The South-to-North Water Diversion Project is an interbasin water diversion project, whose impact on changes in freshwater resources in the Changjiang Estuary is of widespread interest. In this paper, we used a 3D numerical model of estuarine saltwater intrusion to study the impact on saltwater intrusion and freshwater resources in the Changjiang Estuary from both short-term and long-term perspectives. The study, moreover, was focused on the eastern and middle route water transfer schemes of the Project. The results indicate that during the neap-spring tide period in mid-to-late February, the unavailable water intake time, corresponding to salinity greater than 0.45 at the water inlets of the Dongfengxisha, Chenhang, and Qingcaosha is 7.74, 3.08, and 2.72 days, respectively. In the case of a short-term water transfer scheme at river discharge of 1 000 m³/s, saltwater intrusion is intensified, especially at the river mouths of the North Channel, North and South Passages, and in the upper reaches of the North Branch, where salinity rise is most noticeable and a large area shows a salinity rise greater than 0.5; meanwhile, the supply of freshwater in the South Branch decreases. During the neap-spring tide period in mid-to-late February, the unavailable water intake time at the water inlets of the Dongfengxisha, Chenhang and Qingcaosha Reservoirs increases by 1.43, 2.14 and 2.13 days, respectively. In the case of long-term water transfer schemes at river discharge of 1 600 m³/s, the salinity rise in the entire estuary is even more noticeable; a large area of salinity rise greater than 1 shows up on the river mouths of the North Channel, North and South Passages, and a small area of salinity rise greater than 1.5. The supply of freshwater in the South Branch also decreases. During the neap-spring tide period in mid-to-late February, the unavailable water intake time at the water inlets of Dongfengxisha, Chenhang, and Qingcaosha Reservoirs increases by 1.49, 3.08, and 3.08 days, respectively.

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Numerical simulation of erosion and deposition at the water intake channel of the outer seawall sluice in the ecological restoration project area of Chongming Dongtan Bird Habitat

LU Peiyi, ZHU Jianrong, QIAN Weiwei, YUAN Lin

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 43-54. DOI: 10.3969/j.issn.1000-5641.201941013

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A three-dimensional numerical model for erosion and deposition at the water intake channel of the outer seawall of Chongming Dongtan Bird Sanctuary was established based on the hydrodynamic model of the estuary coupled with the sediment module and the bottom erosion and sedimentation equation. The model’s upstream boundary condition at the sluice was specified with water flux calculated by the Weir formula, where the inner water level was calculated by the hydrodynamic model of the Suitang River. The model’s downstream boundary condition of the water level, salinity and sediment concentration were calculated by the large domain numerical model of the Changjiang Estuary. We measured bottom elevations at the water intake channel before and after the sluice opening from July 28 to July 30, 2018 and found that the calculated model elevations were in general agreement with the measured values, indicating that the model can accurately simulate erosion and sedimentation changes. The calculation results for scouring and siltation show that under natural conditions, the water intake channel becomes level after 60 days of sluice closure because of sediment deposit. Siltation is largest near the sluice and gradually decreases with distance from the sluice to the sea. After the water intake channel was naturally silted for two months, the mean erosion thickness at the water intake channel was 96 mm in the case where Suitang River accumulated up to 3.0 m of water and discharged thereafter, 133 mm in the case where Suitang River accumulated up to 3.8 m of water and discharged thereafter, and 625 mm in the case where Suitang River accumulated up to 3.0 m of water and the sluice was opened to receive tidal water. Leaving the sluice open to receive tidal water is the most effective way for scouring sediment in the water intake channel. The research results provide scientific and technical guidance for the protection and management of the ecological restoration project area in Chongming Dongtan National Nature Reserve and the scouring sediment scheme of the water intake channel.

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The development and application of a physical-biogeochemical coupling model based on FVCOM

SHI Shenyang, GE Jianzhong, CHEN Jianzhong, ZHENG Xiaoqin, DING Pingxing

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 55-67. DOI: 10.3969/j.issn.1000-5641.201941008

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By combining the hydrodynamic model FVCOM with the biological model ERSEM, based on FABM, this paper develops a new physical-biogeochemical model: FVCOM-FABM-ERSEM. The combined model is suitable for application to coastal areas and is one of the most comprehensive ecosystem models for the lower trophic levels of the marine food-web. Using the combined model, a one-dimensional vertical (1DV) model and a three-dimensional Changjiang Estuary model were established. The results of the 1DV model were consistent with observation data from the European L4 Station. This paper also simulates the physical and biogeochemical processes of Changjiang Estuary from 2013 to 2016 with the 3D Changjiang Estuary model. The distribution of temperature, salinity, nitrate, phosphate, and chlorophyll-a levels were all found to be consistent with observation data from cruises and MODIS data in the spring when algal blooms occur. The characteristics of the front dynamics of Changjiang Estuary were well represented. The relationship between salinity, turbidity, nutrients, and chlorophyll around the plume front was determined through modeling, indicating a significant co-occurrence effect along the front of physical and biological processes.

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Effects of silver nanoparticles on dissimilatory nitrate reduction in estuarine and tidal sediments

ZHANG Mengxia, ZHENG Yanling, YIN Guoyu, DONG Hongpo, HAN Ping, GAO Juan, LIU Cheng, CHANG Yongkai, LIU Min, HOU Lijun

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 68-77. DOI: 10.3969/j.issn.1000-5641.201941005

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Human activity can cause accumulation of silver nanoparticles (AgNPs) in estuarine and coastal environments; however, the effects of accumulated AgNPs on nitrogen transformation remain unclear. This study investigated the effects of AgNPs on dissimilatory nitrate reduction to ammonium (DNRA) rates in Yangtze estuarine and intertidal sediments using exposure experiments with three different sizes of AgNPs (10 nm, 30 nm, and 100 nm) and three different AgNPs concentrations (0.1 mg/L, 5 mg/L, and 10 mg/L). The results showed that AgNPs inhibited DNRA rates of sediments with different salinity levels, but the inhibition did not increase significantly with time. AgNPs had relatively high inhibition in medium salinity areas depending on the physical properties of the respective sediments. Moreover, it was shown that both the size and concentration of AgNPs were important factors affecting their toxicity. When the concentration of AgNPs was ≤ 5 mg/L, the inhibition of 10 nm AgNPs on the DNRA rate was greater than those of 30 nm and 100 nm AgNPs; the strongest inhibition effects among different salinities reached 16.03% (at 0.2‰ salinity), 20.27% (at 8.0‰ salinity), and 15.36% (at 20‰ salinity). However, when the concentration of AgNPs was 10 mg/L, the inhibition of 30 nm and 100 nm AgNPs on the DNRA rate under the same salinities increased to 17.48%, 33.18%, and 26.45%, respectively; these values were larger than the inhibition of 10 nm AgNPs. There was no significant correlation between Ag⁺ concentration and the inhibition of AgNPs on the DNRA rate (p > 0.05), indicating the inhibitory effect of AgNPs on the DNRA rate could not be fully explained by the toxicity of Ag⁺. These results are of great significance to understand the influence of emerging pollutants on the estuarine nitrogen cycle.

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Response of nitrogen removal in the overlying water to sediment resuspension in the intertidal wetlands of the Yangtze Estuary

ZHANG Hongli, YIN Guoyu, ZHENG Yanling, GAO Juan, GAO Dengzhou, CHANG Yongkai, LIU Cheng

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 78-87. DOI: 10.3969/j.issn.1000-5641.201941007

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The ¹⁵N isotope tracer technique was used to examine the response of denitrification and anammox to sediment resuspension in the intertidal wetlands of the Yangtze Estuary. The results showed that both denitrification and anammox rates were positively correlated with the turbidity of the overlying water, which demonstrates that sediment resuspension can promote the occurrence of nitrogen removal processes in overlying water. The denitrification and anammox rates showed significant spatial differences due to the physiochemical characteristics at different sites under sediment resuspension and was mainly attributed to the sediment TOC contents. In addition, the abundance of nirS and anammox bacterial 16S rRNA genes increased with suspended sediment turbidity, which indicates that sediment resuspension could increase the abundance of nitrogen removal functional bacteria, thus promoting nitrogen removal rates. These results indicate that sediment resuspension has important influence on nitrogen transformation processes and facilitates nitrogen removal in intertidal wetlands.

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Material flux variation and mechanism analysis of different rivers originating from the Tibetan Plateau

ZHANG Xiaocheng, JIANG Xuezhong

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 88-97. DOI: 10.3969/j.issn.1000-5641.201941006

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Many large rivers in Asia originate from the Tibetan Plateau. Changes in the rivers reflect not only changes in the Tibetan Plateau itself, but also relate closely to water resource utilization in the respective basin countries. Changes in terrestrial materials entering the sea reveal the impact of human activities on land-sea interactions in the basin. With changes in natural conditions and socio-economics, material flux from the basin has evolved over time. In this resarch, material flux was compared quantitatively by analysis of the water discharge, sediment load, and nutrient volumes for elements such as nitrogen, phosphorus, and silicon in the Yangtze, Yellow, Mekong, Indus, Ganges, and Brahmaputra Rivers. In addition, the mechanism of variation was discussed by comparison of two phases of land use and land cover in 1995 and 2015, which were extracted from remote sensed image mapping. The results revealed that the runoff of the Yangtze, Indus, and Brahmaputra Rivers decreased significantly from 1995 to 2015, but the Ganges increased over the same period. The Mekong River runoff changed slightly and fluctuated year to year. However, the sediment transportation from river to sea in the Yangtze, Yellow, and Indus Rivers reduced substantially at a statistically significant level (p < 0.05). In terms of nutrient element flux, the dissolved inorganic nitrogen (DIN) of the Yellow and Mekong Rivers showed an upward trend and the Yangtze River DIN decreased by about 26.5%. The total phosphorus and silicon flux in the Yangtze and Mekong Rivers did not change much, while the dissolved inorganic phosphorus (DIP) in the Yellow River decreased. The nitrogen and phosphorus flux was mainly affected by runoff, and the silicate flux was influenced by variations in sediment loads. Furthermore, dam construction, usage of pesticides and fertilizers, and changes in land use have changed the proportion of nutrient elements. An increase in industrial activity, agricultural development, and water conservancy facilities, resulted in a higher total nitrogen and phosphorus flux and more significant reduction in sediment loads. Understanding the material flux data of each basin is of great significance for management departments to build basins with common goals and use water resources reasonably and effectively.

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Evaluation of the effectiveness of a coastal ecological restoration project based on ecosystem services: A case study on Yingwuzhou Wetland, China

WU Wei, LI Caixia, CHEN Xuechu

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 98-108. DOI: 10.3969/j.issn.1000-5641.201941027

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For the last three years, Yingwuzhou Wetland has been operating as the first national-level artificial coastline restoration pilot project in Shanghai; it is important for decision makers, builders, and administrators to understand the effectiveness of the project. In this paper, we study eight key indicators of ecosystem services to evaluate project performance, namely plant supply, water purification, carbon sequestration, climate regulation, wind and wave elimination, biodiversity conservation, recreation, and research and education. The results show that the total value of ecosystem services in Yingwuzhou in 2018 was 437.6×10⁴ yuan·a^–1, and the value per unit area was 18.9×10⁴ yuan·hm^–2·a^–1; the proportional ranking of services can be classified as follows: Cultural Services (45.6%) > Regulation Services (41.9%) > Supporting Services (12.4%) > Provisioning Services (0.1%). The evaluation results show that the value of ecosystem services on the coastline of Yingwuzhou Wetland is significantly improved after ecological restoration; ecosystem services, moreover, are centered on culture and ecology, and the service area has localization characteristics, which has a noticeable effect on improvement of the ecological environment quality at the Jinshan coastline. The results of this study will help to visualize the effectiveness of the restoration of Yingwuzhou Wetland. The research methods can serve as a reference for the evaluation of similar ecological restoration projects in coastal zones.

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Review of driving factors for land degradation and restoration based on IPBES

GUO Xiaona, CHEN Ruishan, LI Qiang, PAN Zhenzhen

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 109-118. DOI: 10.3969/j.issn.1000-5641.201941009

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Land degradation is one of the major global ecological problems that is endangering the health and well-being of 3.2 billion people, threatening food and water security, and reducing biodiversity. Land degradation, moreover, is triggering regional conflicts, large-scale migration and the spread of disease, and has raised widespread concerns from international organizations such as the UN, IPBES, and IPCC in recent years. Understanding the drivers of land degradation is fundamental to preventing land degradation and restoring degraded land. This paper examines the drivers of land degradation based on a land degradation and restoration assessment report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The factors that lead to land degradation can be divided into direct (human) drivers, indirect (human) drivers, and climate change. This paper elaborates on eight types of direct drivers for land degradation, namely grazing land management; cropland and agroforestry management; forests and tree plantation management; non-timber natural resource extraction; fire regime change; extractive industry and energy development; construction, industrial development, and urbanization; and invasive species. This research also explores indirect driving factors and their respective mechanisms, including: population, economy, technology, institution and management, and culture as well as mechanisms (i.e. interaction effects) that are situation-dependent, nonlinear or abruptly-changing, and remotely coupled. The research notes that climate change can also lead to various types of land degradation. Finally, this article reviews driving factors for land degradation in typical areas of China and proposes relevant preventive and response measures. An in-depth understanding of the drivers for land degradation will provide decision making support for “the governance of mountains, water, forests, cropland, lakes, and grass ecosystems” as well as the construction of “Beautiful China”.

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Evaluating service accessibility of residential care facilities in Shanghai for fulfilling basic needs

CHEN Jie, WU Jianping, GUO Peijun, YAO Shenjun

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 119-128. DOI: 10.3969/j.issn.1000-5641.201841038

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Appropriate assessment of the service accessibility of residential care facilities is important for making policies on the allocation of residential care resources. In accordance with policy requirements for the service of residential care facilities in Shanghai, this study modifies the traditional Two-step Floating Catchment Area (2SFCA) method by introducing a power function as a distance decay relationship, employing multi-radius service areas, using the shortest driving distance to measure the distance parameter, and introducing administrative restrictions. With the proposed method, residential care services were calculated and analyzed at the town level. Service accessibility results were then compared under two scenarios. The results show that service accessibility of Shanghai residential care facilities is far below the planning targets for 2020. Less than 1/3 of the towns had service accessibility values with at least 35 beds per thousand elderly people. Comparing the results from two scenarios studied, we found that administrative barriers resulted in lower accessibility for most towns, especially in urban areas where the elderly population density is high; consequently, this significantly enlarged the rural-urban divide.

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A microclimatic impact analysis on multi-dimensional indicators of urban road fabric: Empirical research on Shanghai

JIANG Yunfang, HAN Xuemei, SHI Tiemao, SONG Danran

Journal of East China Normal University(Natural Science) 2020, 2020 (3): 129-147. DOI: 10.3969/j.issn.1000-5641.201941004

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Different historical backgrounds and planning ideas result in different road fabrics for a city. Road fabric patterns affect urban microclimate factors and form a unique local microclimate. In this paper, we studied the road fabric of four “city” areas in Shanghai (i.e., the old downtown area, Gubei international community, Anting new town, and new Jiangwan town) by simulating the microclimate of the four research areas using ENVI-met4.3 software; we then used the data to compare the microclimate status of urban fabric at the medium and micro levels. At the medium level, the relationship between width, orientation, spacing, connectivity, and the climate environment was analyzed. At the micro level, the effects of Near-line Rate, Height to Wide ratio (H/W) and Sky View Factor (SVF) on the distribution characteristics of microclimate factors in roads were analyzed. The comparative analysis of microclimate characteristics at the “city” scale provides useful insights for urban climate adaptability in urban design projects and spatial morphology optimization in future urbanization development.

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Journal of East China Normal University(Natural Science) 2020, 2020 (4): 0-0.

Abstract （173）

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Cohomology and Nijenhuis operators of Lie supertriple systems

GUO Shuangjian

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 1-11. DOI: 10.3969/j.issn.1000-5641.201911017

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We first introduce the notion of representations of a Lie supertriple system and present associated properties. We also study low dimensional cohomology and the coboundary operator of the Lie supertriple system. Lastly, we investigate the deformations and Nijenhuis operators of the Lie supertriple system by choosing suitable cohomology.

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Classification of finite-dimensional real simple Balinsky-Novikov superalgebras

XIA Limeng, ZHAO Shanshan

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 12-17. DOI: 10.3969/j.issn.1000-5641.201911018

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In this paper, we study finite-dimensional Balinsky-Novikov superalgebras, which can be regarded as a class of superanalogues of Novikov algebras. We describe some of their properties and give the complete classification of finite-dimensional simple Balinsky-Novikov superalgebras over the field of real numbers.

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Travelling wave solutions of a diffusive single species model with a strong generic delay kernel

YANG Gaoxiang

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 18-25. DOI: 10.3969/j.issn.1000-5641.201911019

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In this paper, the existence of travelling wave solutions of a diffusive single species model with a strong generic delay kernel is established in two steps. Firstly, in the case of a species model without time delay, the existence of travelling wave solutions of the species model is obtained by using qualitative theories of ordinary differential equations. Secondly, when the time delay is greater than zero and sufficiently small, the existence of travelling wave solutions of the species model is verified by using linear chain techniques and the geometric singular perturbation theory.

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Sharp bounds for Sándor-Yang means in terms of single parameter harmonic and contra-harmonic means

LI Shaoyun, QIAN Weimao, XU Huizuo

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 26-34. DOI: 10.3969/j.issn.1000-5641.201911015

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Using real analysis, this paper reviews the order relations of Sándor-Yang means and single parameter harmonic (or contra-harmonic) means. Two optimal double inequalities are found.

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Stability analysis of neutral neural networks with time-varying delays

LIU Jin, ZHAO Weirui

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 35-44. DOI: 10.3969/j.issn.1000-5641.201911016

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In this paper, a class of neutral neural networks with time-varying delays was considered. First, the existence and uniqueness of equilibrium was obtained using the homeomorphic mapping theorem. Next, by constructing the corresponding Lyapunov functional and using Lyapunov stability theory, sufficient conditions for the global asymptotic stability of equilibrium were established. A comparison between our results and the existing results was made, revealing that our results can be used as criteria for judging the stability of some systems. Lastly, several numerical simulations were carried out to illustrate the results.

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A new cycle structure theorem for Hamiltonian graphs

LI Jingyun, REN Han

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 45-50. DOI: 10.3969/j.issn.1000-5641.201911013

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An $ n $-vertex graph is called pancyclic if it contains a cycle of length $ k $ for every $ k\;(3\leqslant k\leqslant n) $. Pancyclic graphs are an important topic in cycle theory. In this paper, we demonstrate pancyclicity by showing that the distance between two non-adjacent vertices on a Hamiltonian cycle is 3.

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Existence of random attractors for the Berger equation with white noise

SONG An, WANG Xuan

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 51-63. DOI: 10.3969/j.issn.1000-5641.201911011

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In this paper, we study the long-time behaviors of solutions for the Berger equation with white noise. By applying the asymptotic a priori estimates technique and the operator decomposition technique, the existence of random attractors is shown.

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A new blow-up criterion for the nonhomogeneous nonlinear Schrödinger equation

LI Shuangshuang

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 64-71. DOI: 10.3969/j.issn.1000-5641.201911029

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In this paper, the existence of blow-up solutions for the nonhomogeneous nonlinear Schrödinger equation is studied. First, a class of invariant sets is constructed and then the optimal Gagliardo-Nirenberg type inequality is applied; careful analysis is used to prove that for any large $\mu$, there exists $u_{0}\in H^{1}$ so that $E(u_{0})=\mu$ and the solution $u(t,x)$ with $u_{0}$ as an initial value blows up in finite time. This result supplements the existing content in the literature [1].

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Research on slip prediction path planning based on an ant colony algorithm

ZHOU Lanfeng, YANG Lina, FANG Hua

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 72-78. DOI: 10.3969/j.issn.1000-5641.201921010

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The lunar rover is a multi-function, mobile robot equipped with a mission. Under real terrain driving conditions, in addition to selecting the optimal path from the start point to the target point, the robot should take into account the terrain, obstacles, and other influencing factors. The main influencing factors of the terrain are steep slope gradients and slope orientation; other factors are classified as slip. These greatly increase the length and time complexity of path planning as well as the overall safety of the robot. The traditional ant colony algorithm seeks the optimal solution in path planning, but it also encounters problems such as slow convergence speed, high time complexity, and unbalanced optimization. It does not consider factors such as slip and terrain when applied to lunar rover path prediction. It is easy to fall into a local optimal solution when dealing with path planning problems. This paper proposes an improved ant colony algorithm for path planning based on the slope gradient and slope orientation for 3D raster terrain. By applying a consistent pheromone heuristic factor and pheromone volatilization coefficient, changing the terrain parameters for slip prediction, and obtaining a comprehensive cost function based on slip prediction, the traditional ant colony algorithm is improved. The influence of the comprehensive cost function based on slip prediction on the path length, convergence speed, time complexity, and iteration number of the improved ant colony algorithm is analyzed. Finally, experimental simulation data is used to verify that the improved ant colony algorithm is more effective in addressing slip prediction path planning problems.

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Anomaly detection algorithm based on improved K-means for electric power data

WU Rui, ZHANG Anqin, TIAN Xiuxia, ZHANG Ting

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 79-87. DOI: 10.3969/j.issn.1000-5641.201921012

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Anomaly detection methods are widely used for applications in the field of electric power, such as equipment fault detection and abnormal electricity consumption detection. The proposed algorithm combines densities of data objects with the maximum neighborhood radius to select data points that are closer to actual cluster centers for the initial selection; this, in turn, improves random selection of the initial cluster centers. In addition, a new anomaly detection method based on an improved K-means algorithm for electric power data is proposed. Experiments show that the algorithm is more suitable in both clustering performance and anomaly detection. When this algorithm is applied to the field of electric power, abnormal data can be effectively detected.

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Automatic extraction of corporate bankruptcy-related events from ruling documents

YANG Jiale, WANG Junhao, QIAN Weining, LUO Yifeng

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 88-97. DOI: 10.3969/j.issn.1000-5641.201921015

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This paper proposes a framework for extracting corporate bankruptcy-related events from ruling documents and thus extracts structured information about the related events. Combined with ruling documents, our framework uses distant supervision to generate training data; applies named entity recognition techniques to implement sequence label tagging on sentences of litigation documents; and implements event extraction with a self-defined list of event trigger words as well as an event dictionary to detect bankruptcy-related events and gather structured information. Our experimental results demonstrate the effectiveness of the framework.

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Lineage-driven distributed database system with an automated fault injection test tool

SHEN Jing, CAI Peng

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 98-107. DOI: 10.3969/j.issn.1000-5641.201921011

Abstract （320）

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Failures are unavoidable in distributed database systems. To improve the fault tolerance of distributed database systems and verify the accuracy of fault-tolerant protocols, the system should periodically run a fault injection test to artificially trigger a fault during system operations. However, the scale and complexity of distributed database systems make it difficult to fully enumerate inputs and make it impractical to explain all the behaviors that occur in the system. One of the test methods commonly used is a random combination of faults, which is simple but not complete; the other one is guided by professional knowledge and is not universally applicable. Accordingly, we adopted and revised a research prototype, called the lineage-driven fault injection (LDFI) test, that is both complete and universally applicable. We implemented the automation fault injection tool in Cedar. Experiments showed that lineage-driven fault injection tests can successfully detect system bugs caused by complex fault combinations and improve the credibility of the database; these bugs cannot be detected by random fault injection with fewer test cases.

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An improved genetic algorithm to solve the course scheduling problem in the context of new college entrance examinations

XU Xiangyang, LIU Wenwei, FU Die, XU Gang, JIN Cheqing, WANG Xiangfeng, WANG Jiangtao

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 108-123. DOI: 10.3969/j.issn.1000-5641.201921008

Abstract （427）

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After the new policy for college entrance examination reform was put forward in China, an increasing number of regions and senior high schools began to adopt the mobile teaching system. Compared with traditional teaching schedules, which use an executive class, this pattern further increased the challenges of scheduling, and the lack of school education resources has become more prominent. The traditional algorithm for curriculum arrangement is not suitable for solving the scheduling problem that exists with the mobile teaching system. Pure manual scheduling is not only time-consuming and laborious, but there may also be unforeseen conflicts; it is difficult to guarantee the feasibility and rationality of a curriculum. Given the characteristics of a mobile teaching system pattern, this paper presents a method for obtaining high-quality feasible solutions to deal with course scheduling. First, a method for automatically generating combinations of mobile teaching classes is proposed. Second, the improved genetic algorithm is used to solve the scheduling problem efficiently and reasonably. Experiments show that the proposed algorithm can achieve a high-quality curriculum, and the method has been applied in practical applications.

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An improved method for hand gesture estimation based on depth image pre-rotation

XU Zhengze, ZHANG Wenjun

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 124-133. DOI: 10.3969/j.issn.1000-5641.201921004

Abstract （322）

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Hand gesture estimation is much more difficult than human pose estimation from depth images, in part because existing algorithms are unable to recognize different appearances of the same hand gesture after rotation. In this paper, an improved approach for hand gesture estimation based on in-plane image rotation is proposed. First, a convolutional neural network (CNN) was trained by datasets with an auto tagged optimum angle of rotation. Then, prior to hand gesture recognition, an in-plane image of the hand depth was processed by the predicted angle of rotation through the trained CNN model. Lastly, depth pixels were classified by random decision forest (RDF), followed by clustering to generate the hand joint position. Experiments show that this method can reduce the error between the predicted position of the hand joint and the exact position, and the accuracy of gesture estimation improves by about 4.69% from the baseline.

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Model for click-through rate prediction based on sequence features

ZHU Sihan, PU Jian

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 134-146. DOI: 10.3969/j.issn.1000-5641.201921006

Abstract （352）

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The click-through rate (CTR) prediction model is an important component of mainstream recommendation systems. The model assigns a score to recommended items according to the predicted CTR and generates an optimized scoring function which in-turn influences an item’s display strategy; this helps generate improved business conversion rates and a better user experience. Generally, CTR prediction models utilize both user and item features to predict CTR. However, structural characteristics of user behavior, such as frequency and trends, can also reflect behavioral tendencies. Given the absence of this information, this paper analyzes user behavior sequences as a time series and extracts latent features. Factorization machines are then used to learn from user/item features combined with sequence features to improve the quality of prediction. Experiments show that the sequence feature-based methods improve the performance of CTR prediction models and make CTR prediction more accurate.

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Research on an advertising click-through rate prediction model based on feature optimization

HE Xiaojuan, GUO Xinshun

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 147-155. DOI: 10.3969/j.issn.1000-5641.201921007

Abstract （391）

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This paper proposes an online advertising feature extraction model of CNN (Convolutional Neural Networks) based on GBDT (Gradient Boosting Decision Tree) aimed at solving challenges with high-dimensional sparseness in Internet advertising data based on existing theories and technologies for click-through rate (CRT) prediction. The proposed model, CNN⁺, is able to extract deep, high-order features from raw data and solve the issues that convolutional neural networks face in extracting sparse and high-dimensional features. Experimental results on real datasets show that the features extracted by the CNN⁺ model are more effective than two other feature extraction methods studied, namely principal component analysis (PCA) and GBDT.

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Research on repairing anomalous electrical energy data based on the Grey Model

HUANG Fuxing, ZHOU Guangshan, ZHENG Kuanyun, FENG Zejia, YUAN Peisen

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 156-163. DOI: 10.3969/j.issn.1000-5641.201921016

Abstract （283）

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The traditional technique of repairing anomalous electrical energy data requires large amounts of data, has a high operational cost, and results in poor timeliness by using interpolation and other statistical methods; hence, the accuracy and efficiency of repairing results are limited. In this paper, a method for repairing anomalous electrical energy data based on the Grey Model is proposed. The normal historical electrical energy data is taken as an input variable, and the time node electrical energy data at which the abnormal point is located is taken as the output variable. The ratio test and the prediction equation are used to obtain the predicted value. The electrical energy data is iteratively predicted. Finally, the accuracy of the predicted value is tested. The average relative residual of the prediction was found to be 2.182%. The original data is then modified according to the result so as to repair the electrical energy anomaly data. The model prediction and repair are carried out with the actual electrical energy data of a certain area, and the results and errors are analyzed. The feasibility of the method is subsequently verified.

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Ecological restoration effect of paddy fields after rice planting pattern transformation in the rural wetlands of Chenhaiwei, Jiangsu Province

LUO Zukui, LI Yang, XU Xi, QU Mingzhi, MA Jin, SUN Wen, HUANG Shuxin, TONG Huilin

Journal of East China Normal University(Natural Science) 2020, 2020 (4): 164-172. DOI: 10.3969/j.issn.1000-5641.201931009

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In this paper, we evaluated the ecological restoration effect of transforming traditional paddy fields into ecological paddy fields in the rural wetlands of Chenhaiwei. To achieve this objective, we conducted field investigations and laboratory observations, from July 2018 to May 2019, of amphibians, benthic animals, and the water quality at a landscape lake, ecological paddy field, traditional paddy field, and residential ditch. The results showed that：①Amphibian species decreased sequentially from the landscape lake, ecological paddy field, traditional paddy field, and residential ditch. There was not a significant difference in the number of amphibians observed between the landscape lake and the ecological paddy field, but the number of amphibians was significantly higher than those observed at the traditional paddy field and residential ditch. ②There were no significant differences in the types and numbers of benthic species among the four types of habitats in the wet season, but the ecological paddy field showed the least variety and quantity of benthic species in the dry season. ③The water quality indices of organic nitrogen and phosphorus from the ecological paddy field ranked in the middle among the four habitats, but chlorophyll-a concentration was the lowest. In general, ecological recovery improved to a certain extent after transforming the planting pattern of the rice field at Chenhaiwei, but the lack of scientific management is not conducive to species stability. We put forward suggestions for ecological management of paddy fields.

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Journal of East China Normal University(Natural Science) 2020, 2020 (5): 0-0.

Abstract （270）

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High contention transaction processing prototype for e-commerce workloads

ZHANG Shuyan, WANG Qingshuai, ZHANG Rong

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 1-9. DOI: 10.3969/j.issn.1000-5641.202091005

Abstract （374）

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Modern multi-core main-memory databases still cannot achieve ideal performance under high contention. Throughput is considered to be choked by concurrent transactions trying to modify the same data. These transactions contend for the same resources and must be executed serially in a traditional database. Unfortunately, e-commerce workloads often meet with high contentions due to promotions. In this paper, we optimize the transaction processing scheme for high contention e-commerce workloads from two aspects. First, prefiltering is designed to filter invalid modifications to the databases, which can mitigate the contention for locks. Second, if a large number of writes are similar, we propose to do lock sharing among similar writes. We implement a prototype of our proposed system, Filmer, to demonstrate the idea. Extensive experiments have shown that filtering and merging improve efficiency in handling high contention e-commerce workloads.

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Journal of East China Normal University(Natural Science) 2020, 2020 (5): 3-3.

Abstract （323）

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Journal of East China Normal University(Natural Science) 2020, 2020 (5): 4-4.

Abstract （243）

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Global transaction log of a multi-master cloud database

WEI Xiaoxian, LIU Wenxin, CAI Peng

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 10-20. DOI: 10.3969/j.issn.1000-5641.202091002

Abstract （375）

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With the prevalence of cloud computing, users’ requirements for cloud databases are becoming increasingly complex. The current write-once-read-many cloud database system, based on shared storage, cannot support the dynamic expansion of write performance. Multiple master nodes provide write services simultaneously, which can cause cross-node read and write conflicts, eventually leading to inconsistencies in the cache of multiple master nodes. For this problem, optimistic conflict detection based on globally ordered transaction logs can detect cross-node transaction conflicts, roll back conflicting transactions, and maintain the isolation level and consistency of the overall system. By broadcasting and replaying the global orderly transaction log, moreover, the modification of the master node can be synchronized to the remaining nodes to ensure the independent service capability of each individual node. This multi-master cache consistency solution based on global transaction logs is implemented on the open source database MySQL, and the impact on system performance is verified through experiments.

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Research and implementation of a smart automatic contract generation method for Ethereum

GAO Yichen, ZHAO Bin, ZHANG Zhao

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 21-32. DOI: 10.3969/j.issn.1000-5641.202091015

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Smart contracts based on Ethereum have been widely used across various fields. The programming of smart contracts, however, requires professional developers with expertise in a special programming language; in other words, the developers must have professional domain knowledge in addition to programming ability. In this paper, a method for the automated generation of smart contracts for specific domains is proposed with the aim addressing the programming friendliness of smart contracts. The paper introduces cluster analysis of smart contracts and establishes the basic functional code for transactional type smart contracts. MFC is used to link the generated code with UI control and provide users with a friendly smart contract programming page; hence, the automatic generation of smart contracts is realized, thereby reducing the difficulty and cost of contract programming. Finally, a case study is presented to verify the availability of the generated smart contract.

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An integrity auditing scheme based on MHT for power equipment images stored in the cloud

ZHANG Xun, BAI Wanrong, WEI Feng, WANG Rong, TIAN Xiuxia, LIU Tianshun

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 33-43. DOI: 10.3969/j.issn.1000-5641.202091012

Abstract （433）

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This paper proposes an integrity auditing scheme suitable for power equipment images stored in the cloud with the aim of addressing the risks of being attacked, tampered with, or lost. First, each image is cut into four image blocks, and then a Scale Invariant Feature Transform (SIFT) algorithm is used to extract features from the image blocks. The four image blocks for each image are subsequently used as a leaf node to construct a Merkle Hash Tree (MHT). Finally, access level bits and update status bits are added to the nodes of the tree. Theoretical analysis and experimental results show that the proposed image integrity auditing scheme has lower computational overhead and higher audit efficiency compared to existing approaches; hence, the scheme can accurately locate the incomplete area of an image and is suitable for auditing integrity of power equipment images in a cloud storage environment.

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Research on an endogenous data interaction protocol for the dual-middle platform and dual-chain architecture

LIU Feng, YANG Jie, LI Zhibin, QI Jiayin

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 44-55. DOI: 10.3969/j.issn.1000-5641.202091014

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Since dual-middle platform architecture of “data and business” was first proposed, the efficiency of secure data interaction between middle platforms has become particularly important. This paper proposes an efficient interaction protocol, while ensuring data security and credibility with the help of a blockchain dual-chain structure, to optimize the efficiency of endogenous data interaction between middle platforms. By extracting the core threshold signature technology in the new protocol, the simulation experiment showed that the protocol reduced 42.1% of the overhead time used in the off-chain signature and on-chain verification processes compared with the method for traditional single signature and on-chain verification. The new protocol will have a positive impact on the integration of blockchain technology in the middle platform and on accelerating the overall adoption of the middle platform and blockchain.

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Enriching image descriptions by fusing fine-grained semantic features with a transformer

WANG Junhao, LUO Yifeng

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 56-67. DOI: 10.3969/j.issn.1000-5641.202091004

Abstract （441）

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Modern image captioning models following the encoder-decoder architecture of a convolutional neural network (CNN) or recurrent neural network (RNN) face the issue of dismissing a large amount of detailed information contained in images and the high cost of training time. In this paper, we propose a novel model, consisting of a compact bilinear encoder and a compact multi-modal decoder, to improve image captioning with fine-grained regional object features. In the encoder, compact bilinear pooling (CBP) is used to encode fine-grained semantic features from an image’s regional features and transformers are used to encode global semantic features from an image’s global bottom-up features; the collective encoded features are subsequently fused using a gate structure to form the overall encoded features of the image. In the decoding process, we extract multi-modal features from fine grained regional object features, and fuse them with overall encoded features to decode semantic information for description generation. Extensive experiments performed on the public Microsoft COCO dataset show that our model achieves state-of-the-art image captioning performance.

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Methods and progress in deep neural network model compression

LAI Yejing, HAO Shanfeng, HUANG Dingjiang

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 68-82. DOI: 10.3969/j.issn.1000-5641.202091001

Abstract （464）

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The deep neural network (DNN) model achieves strong performance using substantial memory consumption and high computational power, which can be difficult to deploy on hardware platforms with limited resources. To meet these challenges, researchers have made great strides in this field and have formed a wealth of relevant literature and methods. This paper introduces four representative compression methods for deep neural networks used in recent years: network pruning, quantization, knowledge distillation, and compact network design; in particular, the article focuses on the characteristics of these representative models. Finally, evaluation criteria and research prospects of model compression are summarized.

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Approaches on network vertex embedding

ZHOU Xiaoxu, LIU Yingfeng, FU Yingnan, ZHU Renyu, GAO Ming

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 83-94. DOI: 10.3969/j.issn.1000-5641.202091007

Abstract （317）

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Network is a commonly used data structure, which is widely applied in social network, communication and biological fields. Thus, how to represent network vertices is one of the difficult problems that is widely concerned in academia and industry. Network vertex representation aims at learning to map each vertex into a vector in a low-dimensional space, and simultaneously preserving the topology structure between vertices in the network. Based on the analysis of the motivation and challenges of network vertex representation, this paper analyzes and compares the mainstream methods of network vertex representation in detail, including matrix decomposition, random walk and deep learning based approaches, and finally introduces the methods to measure the performance of network vertex representation.

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Approaches for semantic textual similarity

HAN Chengcheng, LI Lei, LIU Tingting, GAO Ming

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 95-112. DOI: 10.3969/j.issn.1000-5641.202091011

Abstract （652）

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This paper summarizes the latest research progress on semantic textual similarity calculation methods, including string-based, statistics-based, knowledge-based, and deep-learning-based methods. For each method, the paper reviews not only typical models and approaches, but also discusses the respective advantages and disadvantages of each routine; the paper also explores public datasets and evaluation metrics commonly used. Finally, we put forward several possible directions for future research in the field of semantic textual similarity.

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Relation extraction via distant supervision technology

WANG Jianing, HE Yi, ZHU Renyu, LIU Tingting, GAO Ming

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 113-130. DOI: 10.3969/j.issn.1000-5641.202091006

Abstract （933）

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Relation extraction is one of the classic natural language processing tasks that has been widely used in knowledge graph construction and completion, knowledge base question answering, and text summarization. It aims to extract the semantic relation from a target entity pair. In order to construct a large-scale supervised corpus efficiently, a distant supervision method was proposed to realize automatic annotation by aligning the text with the existing knowledge base. However, it highlights a series of challenges as a result of over-strong assumptions and, accordingly, has attracted the attention of researchers. Firstly, this paper introduces the theories of distant supervision relation extraction and the corresponding formal descriptions. Secondly, we systematically analyze related methods and their respective pros and cons from three perspectives: noisy data, insufficient information, and data imbalance. Next, we explain and compare some benchmark corpus and evaluation metrics. Lastly, we highlight new subsequent challenges for distant supervision relation extraction and discuss trends and directions of future research before concluding.

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The role of the middle platform in digital government implementation

CHEN Bing, FANG Haibin, ZHAO Wenwen

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 131-136. DOI: 10.3969/j.issn.1000-5641.202091008

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This paper introduces the characteristics of digital government by reviewing the development of digital government systems. Combined with the development of IT technology, it is demonstrated that the middle platform is an important technical support component for the construction of digital government. Using a case study on the building process of Shanghai’s “Integrated Online Platform”, this paper introduces the construction process of the middle platform on the business, data, and application aspects of government affairs; the article also offers a summary for the future direction of development.

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Methodology for building a business-oriented data asset system: Feature hierarchies

REN Yinzi

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 137-145. DOI: 10.3969/j.issn.1000-5641.202091009

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This paper proposes a new method for building a business-oriented data asset system. Data assets are one of the core components of the data middle office concept and require business-oriented asset mapping to realize the transformation from the asset to the broader business value. The proposed methodology uses feature hierarchies and describes how to organize data assets based on a tree structure, with the root as an object, the branch as a category, and a leaf/flower as a tag. There are energetic connections between the various object trees and the growth of these trees is supplied by the business. The instantiation of feature hierarchies can be realized in two modes: overall planning and local interception. The asset results are divided into two major parts, namely asset inventories and asset entities; these can be quickly configured as data service results for business use through service management tools in order to realize the value of the underlying data assets.

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Research on abnormal detection of daily loss rate based on a variational auto-encoder

ZHANG Guofang, LIU Tongyu, WEN Lili, GUO Guo, ZHOU Zhongxin, YUAN Peisen

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 146-155. DOI: 10.3969/j.issn.1000-5641.202091013

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This paper adopts an anomaly detection algorithm based on a self-encoder to achieve anomaly detection of large-scale daily line loss rate data. A variational auto-encoder is a neural network that uses the backpropagation algorithm to make the output value approximately equal to the input value. It uses the auto-encoder to encode the original daily line loss rate time series and records the reconstruction possibility at each time point during the reconstruction process. When the reconstruction possibility is greater than a specified threshold, it is classified as anomaly data. In this paper, experiments were conducted on real daily line loss data. The test results show that the proposed algorithm for abnormal detection of daily line loss rate data based on an auto-encoder has good detection capability.

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GRS: A generative retrieval dialogue model for intelligent customer service in the field of e-commerce

GUO Xiaozhe, PENG Dunlu, ZHANG Yatong, PENG Xuegui

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 156-166. DOI: 10.3969/j.issn.1000-5641.202091010

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There are generally two ways to realize most intelligent chat systems: ① based on retrieval and ② based on generation. The content and type of responses, however, are limited by the corpus chosen. The generative approach can obtain responses that are not in the corpus, rendering it more flexible; at the same time, it is also easy to produce errors or meaningless replies. In order to solve the aforementioned problems, a new model GRS (generative retrieval score) is proposed. This model can train the retrieval model and the generation model simultaneously. A scoring module is used to rank the results of the retrieval model and the generation model, and the responses with high scores are taken as the output of the overall dialogue system. As a result, GRS can combine the advantages of both dialogue systems and output a specific, diverse, and flexible response. An experiment on a real-world JingDong intelligent customer service dialogue dataset shows that the proposed model offers better outputs than existing retrieval and generation models.

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Merchant churn prediction based on transaction data of aggregate payment platform

XU Yiwen, LI Xiaoyang, DONG Qiwen, QIAN Weining, ZHOU Fang

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 167-178. DOI: 10.3969/j.issn.1000-5641.202091016

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In the field of aggregate payments, ensuring a low dropout rate of merchants on the platform is a key issue to reduce the overall platform operating cost and increase profit. This study focuses on the prediction of merchant churn for aggregate payment platforms and aims to help the platform reactivate potential churn merchants. The paper proposes a series of features that are highly relevant to merchant churn and applies a variety of traditional machine learning models for prediction. Given that the data analyzed contains sequential information, the study, moreover, applies LSTM-based techniques to address the prediction problem. Experimental results on a real dataset show that the proposed features have a certain predictive ability and the results are interpretable. And, the LSTM-based approaches are capable of capturing the timing characteristics in the data and further improve prediction results.

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Discovering traveling companions using autoencoders

LI Xiaochang, CHEN Bei, DONG Qiwen, LU Xuesong

Journal of East China Normal University(Natural Science) 2020, 2020 (5): 179-188. DOI: 10.3969/j.issn.1000-5641.202091003

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With the widespread adoption of mobile devices, today’s location tracking systems are producing tremendous amounts of trajectory data on a continuous basis. The ability to discover moving objects that travel together (i.e., traveling companions) from their respective trajectories is desirable for many applications, including intelligent transportation systems and intelligent advertising. Existing algorithms are either based on pattern mining methods that define a particular pattern of traveling companions or based on representation learning methods that learn similar representations for similar trajectories. The former method suffers from the pairwise point-matching problem, and the latter often ignores the temporal proximity between trajectories. In this work, we propose a deep representation learning model using autoencoders, namely Mean-Attn (Mean-Attention) , for the discovery of traveling companions. Mean-Attn collectively injects spatial and temporal information into its input embeddings using skip-gram and positional encoding techniques, respectively. In addition, our model encourages trajectories to learn from their neighbors by leveraging the sort-tile-recursive (STR) algorithm as well as the mean operation and global attention mechanisms. After obtaining the representations from the encoder, we run DBSCAN (Density-Based Spatial Clustering of Applications with Noise) to cluster the representations and find traveling companions. Experimental results suggest that Mean-Attn performs better than the state-of-the-art data mining and deep learning algorithms for locating traveling companions.

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Journal of East China Normal University(Natural Science) 2020, 2020 (6): 0-0.

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The Fourier transform of trigonometric functions on the multiplicative group ${\mathbb Z}^{\times}(m)$

Lichien SHEN

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 1-15. DOI: 10.3969/j.issn.1000-5641.201911023

Abstract （379）

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Based on the Fourier transform on the multiplicative group $ {\mathbb Z}^{\times}(m)$, we study a class of trigonometric sums and reveal interesting connections between these sums and number theoretic quantities, such as Gauss sums, the class number of imaginary quadratic fields, and the Bernoulli number.

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Robust dissipative control for discrete-time periodic Markovian jump systems

LI Xiuying, JIANG Nan

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 16-23. DOI: 10.3969/j.issn.1000-5641.201911036

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In this paper, we discuss the robust dissipative control problem of uncertain discrete-time periodic Markovian jump systems with incomplete transition rates. By employing the Lyapunov function, a periodic state feedback controller using linear matrix inequalities is designed, that ensures the resultant closed-loop system with incomplete transition rates is stochastically stable and strictly dissipative. Lastly, an example is given to illustrate the effectiveness of the proposed method.

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Vertex-distinguishing E-total coloring of a complete bipartite graph K_{9, n} (93 ≤ n ≤ 216)

CHEN Xiang’en, YANG Weiguang

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 24-29. DOI: 10.3969/j.issn.1000-5641.201911028

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Let $G$ be a simple graph. A total coloring $f$ of $G$ is called an E-total coloring if no two adjacent vertices of $G$ receive the same color, and no edge of $G$ receives the same color as one of its endpoints. For an E-total coloring $f$ of a graph $G$, if $C(u)\neq C(v)$ for any two distinct vertices $u$ and $v$ of $V(G)$, where $C(x)$ denotes the set of colors of vertex $x$ and of the edges incident with $x$ under $f$, then $f$ is called a vertex-distinguishing E-total coloring of $G$. Let $\chi _{vt}^{e}(G)=\min\{k: G$ has a $k$-VDET coloring$\}.$ Then, $\chi _{vt}^{e}(G)$ is called the VDET chromatic number of $G$. By using contradiction, the method of a combinatorial analysis and the method of constructing specific coloring, the VDET coloring of a complete bipartite graph $K_{9, n}$ is discussed and the VDET chromatic number of $K_{9, n}\; (93\leqslant n\leqslant 216)$ is determined.

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Datko-Pazy theorem for nonuniform exponential expansiveness of linear skew-product semiflows

YUE Tian, SONG Xiaoqiu

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 30-37. DOI: 10.3969/j.issn.1000-5641.201911042

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In this paper, the nonuniform exponential expansiveness of linear skew-product semiflows is studied in Banach spaces based on Lyapunov norms. Some continuous and discrete versions of necessary and sufficient conditions for nonuniform exponential expansiveness are obtained via Datko-Pazy methods. The obtained conclusions are generalizations of well-known results in exponential stability and exponential dichotomy theory (Datko, Pazy, Preda et al.). Herein, we apply the main results to the study of nonuniform exponential dichotomy of linear skew-product semiflows.

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Existence and multiplicity of positive solutions for fourth-order boundary value problems with a fully nonlinear term

YAO Yanyan, LI Jiemei

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 38-45. DOI: 10.3969/j.issn.1000-5641.201911026

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In this paper, we discuss the fourth-order two-point boundary value problem $\left\{ {\begin{array}{*{20}{l}} {{u^{(4)}}(t) = f(t,u(t),u'(t),u''(t),u'''(t)),t \in (0,1), }\\ {u(0) = u'(0) = u''(1) = u'''(1){\rm{ = 0}}. } \end{array}} \right.$ Here, the nonlinear term $f$ contains $u'$, $u''$ and $u'''$; therefore, the problem is a fourth-order boundary value problem with a fully nonlinear term. By using the two fixed point theorems of Leggett-Williams type, the existence of at least two or at least three positive solutions are obtained under the term $f$ that satisfies certain conditions. Finally, two examples are given to verify the theorems.

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An algebroidal function of infinite order with given T directions

ZHANG Jin

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 46-51. DOI: 10.3969/j.issn.1000-5641.201911021

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This paper explores the existence of infinite order meromorphic functions and algebroidal functions with given T directions. An algebroidal function $ \omega(z) $ of infinite order was constructed such that for an arbitrary given non-empty closed set of real numbers $ E\pmod {2\pi} $, $\{z: \arg z = \theta, \theta\in E\}$ is the set of all T directions and Borel directions of infinite order of $ \omega(z) $; using a method of cyclic values-assigned, the distribution of singular directions for meromorphic functions and algebroidal functions of infinite order is obtained.

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CedarAdvisor: A load-adaptive automatic indexing recommendation tool

YANG Wencan, HU Huiqi, DUAN Huichao, HU Yaoyi, QIAN Weining

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 52-62. DOI: 10.3969/j.issn.1000-5641.201921013

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Indexes play a pivotal role in improving the performance of queries. One of the important tasks of database administrators is to select appropriate indexes for databases. However, with the increasing complexity of database workloads, the rising amount of data volumes, and the gradually increasing number of tables, it has become more and more difficult to artificially analyze workload cost, select appropriate indexes, and estimate database spatial changes. This paper designs a load-oriented automatic indexing recommendation tool: CedarAdvisor. It collects workload automatically from logs and counts query frequency. First, it generates a candidate index for each query and then evaluates the respective revenue and cost of these candidates. Finally, it generates an indexing recommendation for the complete workload through a dynamic programming algorithm. We verify the effectiveness of the tool through experiments on the distributed database.

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Online map matching algorithm based on the gated recurrent unit model

CHEN Liangjian, XU Jianqiu

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 63-71. DOI: 10.3969/j.issn.1000-5641.201921022

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Map matching is a key technology in the field of road network trajectory data analysis. A fast and accurate map matching algorithm can provide good technical support for upper-layer applications. With the explosive growth of trajectory data, existing online map matching algorithms experience a delay phenomenon; in particular, in the context of low-frequency trajectory data, it is impossible to quickly perform map matching on trajectory data. The development of neural networks and deep learning provide new methods for solving these problems. This paper uses the gated recurrent unit(GRU) model to quickly locate candidate segments of trajectory sampling points, thus accelerating the calculation process for online map matching. The proposed method is experimentally compared to the latest online map matching algorithm; the results show that the GRU-based online map matching algorithm can effectively speed-up the matching process and improve matching efficiency.

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A certificate management system for the completion of online education based on blockchain technology

HUANG Libo, WANG Wei, XU Yanjun, CHEN Xugang

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 72-81. DOI: 10.3969/j.issn.1000-5641.201921019

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In the current educational environment, online education lacks credible proof of completion. After learning courses on the online education platform, the students cannot get a credible certificate of completion; the completion certificate given by a few educational platforms cannot be recognized by the society because of its centralized storage, which limits the development of online education. In order to solve these problems, the blockchain-based online education completion certificate management system is designed and implemented by using the characteristics of decentralization and non-tampering of the blockchain. The electronic certificate of completion is in the form of digital assets, and the student’s learning record is kept in the certificate of completion, which guarantees the authenticity and reliability of the certificate. On this basis, based on the Hyperledger Fabric, smart contracts such as certificate generation and distribution are realized to ensure that they do not need to be operated by third parties. At the same time, multiple query interfaces are provided by the system, such as the historical trace of the certificate, which improve the efficiency of verification of online education platform learning outcomes; in addition, online education courses are recorded in blockchain in the form of publisher’s assets, which enhances copyright protection in online education.

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A method for community contribution incentives based on ethereum

XIAO Dalong, ZHANG Jingwei, YANG Qing, ZHOU Ya

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 82-89. DOI: 10.3969/j.issn.1000-5641.201921014

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Monetization of community contributions is a way to promote community development. The existing solution, implemented on the Internet, requires that the platform’s manager controls the distribution and use of community tokens (i.e., currency issued by private or institutional entities), which hinders community development. In this paper, we propose a method to motivate community members to make contributions. The proposed method primarily relates to token allocation, voting, trading, and community arbitration based on tokens and votes. It transforms the contribution of the community into cryptocurrency, and the tokens’ owners are positively correlated with the contributions they make; this concept effectively reflects contribution to the community. The voting results reflect the will of the community. The deposit model defines supply requirements for the tokens. Finally, we use statistics on the use of gas with smart contracts. The results show that the average cost of gas is currently around 70 000, and the cost of gas with the proposed method is less.

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Study of an improved hybrid particle swarm optimization algorithm for solving 0-1 knapsack problems

YAO Ruoxia, XUE Dan, XIE Juanying, FAN Hong

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 90-98. DOI: 10.3969/j.issn.1000-5641.201921025

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In order to solve 0-1 knapsack problems with greater stability and efficiency, we propose a BPSOSA-CGOO (Hybrid optimization algorithm based on the BPSO (binary particle swarm optimization), the simulated annealing (SA) algorithm and the combined greedy optimization operator (CGOO)) algorithm which is composed of the BPSO, the greedy optimization strategy, and the simulated annealing algorithm. Simulation experiments of 9 groups of different dimensions show that the BPSOSA-CGOO algorithm can solve 0-1 knapsack problems efficiently for small population sizes and iteration times. Meanwhile, it was observed that experiments performed with the algorithm can also find a better solution for 20-dimensional test data. In independent and repeated experiments, the BPSOSA-CGOO algorithm can achieve the optimal solution with high probability for both low-dimensional and high-dimensional knapsack problems; hence, stability and reliability is significantly improved when using the BPSOSA-CGOO algorithm to solve high-dimensional knapsack problems.

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The adoption process for disruptive innovation: A theoretical analysis

WANG Ye, QU Linchi

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 99-104. DOI: 10.3969/j.issn.1000-5641.202021002

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Looking back on history, we observe that many industries generate disruptive innovations intermittently. It is worth noting that those who adopt new technologies for commercialization are usually not the incumbent leading companies with the strongest technical and financial strength, but rather companies that are established later in time, who operate on a smaller scale and with less technical strength. This article explains this phenomenon based on a two-stage game model. The advantages of incumbent companies in traditional technologies often become obstacles in their switch to innovative technologies. Companies established later in time can leverage the late-comer advantage to strategically reduce profits of new technology products, thereby blocking incumbent enterprises from the new product market.

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Defect detection on aluminum surfaces based on deep learning

ZHANG Xu, HUANG Dingjiang

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 105-114. DOI: 10.3969/j.issn.1000-5641.201921021

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With the application of information technology to industrial manufacturing, big data research in industrial manufacturing has become an important basis for realizing intelligent manufacturing and helping the government to guide the transformation and upgrade of manufacturing enterprises. In traditional metal manufacturing industries, like steel and aluminum, there are challenges, such as uncalibrated and rudimentary production techniques. Therefore, it is urgent to improve production processes and production efficiency by using newer generation information technology, such as artificial intelligence. The surface of aluminum, for example, must be inspected during the manufacturing process. Existing surface defect detection techniques for aluminum materials is limited to traditional manual naked eye inspection-which is very laborious-or traditional machine vision algorithms-which have a low rate of detection. Hence, surface defects cannot be accurately judged in a timely fashion. This paper studies the use of deep learning for surface defect detection of aluminum materials. Firstly, two major target detection algorithms, Faster R-CNN and YOLOv3, are used to detect the defects on a set of aluminum materials. Then, based on the YOLOv3 algorithm, the detection ability of small defects on aluminum surfaces was improved. We conducted experiments on the “Aluminum Profile Defect Recognition” dataset provided by the Guangdong Industrial Intelligent Manufacturing Big Data Innovation Competition. The experimental results showed that the mean average precision (mAP) of the improved algorithm is 3.4% higher than that of YOLOv 3 and 1.8% higher than that of Faster R-CNN.

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Online portfolio selection based on quadratic smooth-gray prediction

LIU Xiaoyu, HUANG Dingjiang

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 115-128. DOI: 10.3969/j.issn.1000-5641.201921020

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In recent years, online portfolios have been a popular topic of research in computational finance. The existing strategies used to forecast stock prices is not ideal, and accurate prediction of stock prices is important for evaluating investment portfolios. Considering the lag in stock prices and the complexity of their distribution, this paper makes use of second-order information in stock prices, for the first time, and proposes four strategies, namely DMAR(DMA(double moving average) reversion), DEAR(DEA(double exponential average) reversion), GMR(GM reversion), and DA-GMR(DA-GM reversion). The second-order moving average method, the second exponential sliding prediction method, and the gray prediction method are used to predict price data for the next period; integrated learning optimizes the results of second-order smoothing prediction and the gray prediction is used to obtain the predicted price. Next, we use PA(passive-aggressive) algorithms to update the portfolio, and we arrive at four portfolio strategies. We verify the effectiveness of these strategies using real data from the financial market. The results show that compared with existing algorithms, the four strategies proposed in this paper achieved higher cumulative returns on datasets for NYSE(O), NYSE(N), DJIA, and MSCI.

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Research on a Tang Poetry automatic generation system based on an evolutionary algorithm

MU Zhaonan, LIU Mengzhu, SUN Jieping, WANG Cheng

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 129-139. DOI: 10.3969/j.issn.1000-5641.201921017

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In this paper, research on an automatic generation algorithm for Tang poetry, one of the poetry genres, is carried out. The research work consists of the GloVe(Global Vectors for Word Representation) model to train-word vectors, an initial population scheme based on keywords and peaceful rhymes, a fitness function for grammatical and semantic weights, and a selection strategy used in tournament algorithms; the latter includes heuristic crossover and heuristic mutation operators as well as automatic generation of Tang poetry based on an evolutionary algorithm. Experiments show that by providing keywords the established model and system can achieve the initial goal for automatic generation of Tang poems. After manual modification, the proposed system can generate valuable and appreciable Tang poems.

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New records of Oedichirus astoni and Procirrus lewisii (Coleoptera: Staphylinidae: Paederinae)

XU Wang, LIANG Hong, TANG Li, ZENG Qinghuai, QIAO Yujia

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 140-143. DOI: 10.3969/j.issn.1000-5641.201932007

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In a survey of rove beetles in Qiniangshan Nature Reserve of Guangdong Province, we found two new species: Oedichirus astoni Rougemont, 2017 and Procirrus lewisii Sharp, 1889. The diagnostic characteristics of these two species are described and illustrated in this paper.

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Spatial and temporal distribution of petroleum pollution and influence factors in the Taipu River

LI Gen, XIE Yihan, WANG Huaxiang, YANG Kai

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 144-153. DOI: 10.3969/j.issn.1000-5641.201931010

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The spatial and temporal distribution of petroleum pollution in the Taipu River was analyzed using a clustering methodology. The stationary source and mobile source of petroleum pollution were surveyed and monitored to determine their influence on the Taipu River. The results showed that the average over-limit rate of petroleum pollution was 62.96% among the 9 monitoring stations in the Taipu River. Luxu bridge (S4) and Jinze hydrometric station (S5) in the middle and lower Taipu River, respectively, were the primary stations with petroleum pollution. The peak level of petroleum pollution was observed during the dry period of the Taipu River. Petrol stations and wharves in the estuary of Fenhu Lake were the primary stationary source of petroleum pollution in the trunk stream of Taipu River. The mobile source of petroleum pollution from boats was primarily concentrated on the middle and lower Taipu River, and the number of transit boats had a significant positive correlation with the concentration of petroleum pollution. Based on the spatial and temporal distribution of petroleum pollution in the Taipu River, this article proposes guidelines for petroleum pollution prevention and policy implications.

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A study on temporal and spatial distribution characteristics of dissolved oxygen in surface water of megacities

WANG Huaxiang, CHU Xiaoye, CHEN Ying, XU Lu, YANG Kai

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 154-163. DOI: 10.3969/j.issn.1000-5641.201931011

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The dissolved oxygen (DO) zoning method was used to analyze the temporal and spatial characteristics of 259 river monitoring sites in Shanghai in 2016. The results showed that: ① Time periods with the highest mean DO can be ranked according to the following sequence: winter > spring > autumn > summer, non-flood period > flood period. ② DO had significant spatial stratification. Low-oxygen areas (DO < 2 mg/L) were mainly distributed in highly urbanized geographies, such as the city center and nearby suburban areas, changing with both season and flood period and seemingly affected by surface runoff and the discharge of pumping stations. High-oxygen areas (DO > 6 mg/L) were distributed in areas with high water ecological environmental requirements and occasionally appeared in the suburbs. Most of the annual changes in DO belonged to the median areas (DO: 4 ~ 6 mg/L), and were affected by both industry and agriculture. ③ Correlation anlysis of water quality factors indicated that DO was significantly correlated with water temperature (–0.434), pH(0.332), COD_Mn(–0.219), COD_Cr(–0.234), BOD₅(–0.197), NH₃-N(–0.299), TP(–0.370), TN(–0.191), Vol-P(–0.159), petroleum(–0.207). Stepwise regression analysis showed that DO was significantly affected by T, pH, NH₃-N, TP and petroleum; the analysis showed, furthermore, that DO restricted factors varied in different seasons.

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Remote interview identity authentication based on audio comparison

LIN Xiaoqin, MAO Min, GONG Lingling, JI Li

Journal of East China Normal University(Natural Science) 2020, 2020 (6): 164-171. DOI: 10.3969/j.issn.1000-5641.201942001

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There are vulnerabilities in conducting remote interviews via simple real-time communication software. To this end, this paper proposes a simple and easy remote identity authentication scheme, whereby the recruitee only needs to use general communication software. There is no need to install special software or special hardware systems, which is particularly convenient for recruitees residing in remote areas or international locations. Recruiters need to install audio capture and screen capture software on their computer; once the recruitee is admitted into the interview, the recruiter can achieve identity authentication using audio and video comparison technology. In order to verify the feasibility of this scheme, we carried out two rounds of experiments, collecting remote voice data from seven different countries through a series of software analysis tools as well as manual comparison. The experimental results show that the scheme has a high degree of accuracy for identity authentication, laying the foundation for prospective fully automatic authentication.

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Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 0-0.

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Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 0-0.

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Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 0-0.

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Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 0-0.

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The 21st century Maritime Silk Road and the role of Myanmar

Khin Kyi TUN, Zaisheng XIANG

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 1-5. DOI: 10.3969/j.issn.1000-5641.202092101
Online available: 22 January 2021

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Review of the translation and spreading of Chinese books in Egypt

Nada MOGHITH

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 6-10. DOI: 10.3969/j.issn.1000-5641.202092102
Online available: 22 January 2021

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Geopolitics of CPEC and the future of China and Pakistan

Ayesha KHAN

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 11-14. DOI: 10.3969/j.issn.1000-5641.202092103
Online available: 22 January 2021

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Overseas mergers and acquisitions: Political affiliation and equitable nature based on Belt and Road Initiative

Nazia FEROZE, Tongshun CHENG, Muhammad Sabil FAROOQ, Tongkai YUAN

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 15-23. DOI: 10.3969/j.issn.1000-5641.202092104
Online available: 22 January 2021

Abstract （381）

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What can the Maritime Silk Road learn from the rise and fall of the Songhai Empire?

Ibrahim KONE

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 24-26, 43. DOI: 10.3969/j.issn.1000-5641.202092105
Online available: 22 January 2021

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Study of Chinese overseas student groups at Al-Azhar University: Between 1931 and 1938

Sameh Ahmed Ali ELMASHALY, Tao MU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 27-31. DOI: 10.3969/j.issn.1000-5641.202092106
Online available: 22 January 2021

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A study on the date of manufacture and social function of the celadon ding incense burner unearthed from the Zhanggongxiang kiln

SEONGGowoon, Zhaohui LIU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 32-36. DOI: 10.3969/j.issn.1000-5641.202092108
Online available: 22 January 2021

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The CPEC and sustainable economic growth for Pakistan

Xiaozhong HU, Raza HASNAIN

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 37-39. DOI: 10.3969/j.issn.1000-5641.202092110
Online available: 22 January 2021

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The Sino-India Maritime Silk Road in the Tang Dynasty and its impact on India

Adeel SHEHZAD

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 40-43. DOI: 10.3969/j.issn.1000-5641.202092111
Online available: 22 January 2021

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Betrothal gifts: A comparative study of Chinese and Yoruba marriage traditions

Ajibola OGUNBIYI, Yangqian KE, Wenzhi LI, Adenike ADEGELU, Baikai ZHANG

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 44-47. DOI: 10.3969/j.issn.1000-5641.202092112
Online available: 22 January 2021

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Building a community for a shared future: The 21st Century Maritime Silk Road and its impact on the economic, security, and environmental global governance of oceans and seas— The case of the Gulf of Guinea

Godfred Sowah KHARTEY

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 48-52. DOI: 10.3969/j.issn.1000-5641.202092113
Online available: 22 January 2021

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The importance of China for Iran’s revival in the international community

Elisa MARINELLI, Sajjad ROSHANDEL

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 53-56. DOI: 10.3969/j.issn.1000-5641.202092114
Online available: 22 January 2021

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Empirical analysis of the impact of education on total factor productivity: Case of the Republic of Congo

Jody Excellent BATANTOU-ALLAN, Qiang WANG, André MOULÉMVO, Christian Gatien PASSI BATANTOU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 57-61. DOI: 10.3969/j.issn.1000-5641.202092115
Online available: 22 January 2021

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Comparative biological analysis to investigate the genetic hierarchy of the Indus valley civilization

Muhammad Hidayatullah KHAN, Muhammad Asadullah KHAN, Ali AKBAR, Jian YUE

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 62-66. DOI: 10.3969/j.issn.1000-5641.202092116
Online available: 22 January 2021

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How CPEC and BRI can transform Pakistan’s image regarding FDI and the peace submarine cable system

Saddique KAMRAN, Xiumei LIU, Baoqin WU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 67-70. DOI: 10.3969/j.issn.1000-5641.202092118
Online available: 22 January 2021

Abstract （317）

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China’s Maritime Silk Road and India’s strategic perspective

Vithiyapathy PURUSHOTHAMAN

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 71-73. DOI: 10.3969/j.issn.1000-5641.202092119
Online available: 22 January 2021

Abstract （386）

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A review about tectonic and sedimentary input evolution of the Red Sea rifting basin

I. Mohamed ABDUALLAH M., Tangyan LIU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 74-78. DOI: 10.3969/j.issn.1000-5641.202092201
Online available: 22 January 2021

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A study of the fauna of Mangroves National Park (or Muanda Marine Reserve)

Ekyamba Isaac SHABANI, Manhong LIU, Vitekere KASEREKA, Wetshokonda Alice EKOKO, Xu SUN, Xiaoyu LI, Hongxian YU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 79-83. DOI: 10.3969/j.issn.1000-5641.202092203

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Natural gas hydrates potential in Pakistan: A possible solution to meet future energy demands

Ubedullah ANSARI, Yuanfang CHENG, Xiaohui ZHOU, Jiping DING, Qingchao LI

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 84-88. DOI: 10.3969/j.issn.1000-5641.202092206

Abstract （385）

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A preliminary study on phytoplankton composition at Bashayer II marine oil terminal, Red Sea, Sudan

Osama SAAD S., Amjed AHMED G.

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 89-93. DOI: 10.3969/j.issn.1000-5641.202092209

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The use of remote sensing and GIS to detect and simulate changes in the largest mangrove community of Iran

NIYA Ali KOUROSH, Jinliang HUANG

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 94-98. DOI: 10.3969/j.issn.1000-5641.202092210

Abstract （395）

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Deep Sea Port development in Myanmar

Saw Nu Sanda THEIN, Hualong YANG

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 99-103. DOI: 10.3969/j.issn.1000-5641.202092211

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The impacts of climate change on the coastal zone of Mauritius

Yuvna Devi PERIANEN, Xi XIAO

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 104-108. DOI: 10.3969/j.issn.1000-5641.202092213
Online available: 22 January 2021

Abstract （529）

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Historical overview of hypoxia in the Bay of Bengal

Md Jaker HOSSAIN, Aftab Uddin SHEIKH, Jing ZHANG

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 109-113. DOI: 10.3969/j.issn.1000-5641.202092218
Online available: 22 January 2021

Abstract （466）

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Sustainable adaption strategies for freshwater supply-related challenges in coastal cities, Tanzania

M. Jamila NGONDO, Heqin CHENG, M. Alfonse DUBI, Joel NOBERT

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 114-119. DOI: 10.3969/j.issn.1000-5641.202092221
Online available: 22 January 2021

Abstract （338）

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Erodibility of cohesive sediments along the Nigerian transgressive mud coast: A preliminary experimental study

Rasheed ADESINA, Olusegun DADA, Yinusa ASIWAJU-BELLO, Zhiguo HE

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 120-124. DOI: 10.3969/j.issn.1000-5641.202092222
Online available: 22 January 2021

Abstract （363）

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Eddy heat and salt transport in four typical regions in the Bay of Bengal

Lasitha PERERA, Gengxin CHEN, Tilak GAMAGE, Dongxiao WANG

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 125-129. DOI: 10.3969/j.issn.1000-5641.202092224
Online available: 22 January 2021

Abstract （372）

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Paleoceanographic history of the Bohol Sea, Philippines from the last 25 ka based on calcareous nannofossil and sedimentological records

Adrian Raymund Cruz FERNANDEZ, Allan Gil Salazar FERNANDO, Zhifei LIU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 130-135. DOI: 10.3969/j.issn.1000-5641.202092227
Online available: 22 January 2021

Abstract （436）

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The future of Sino-Eurasian integration

Yerkenaz KARIBAYEVA

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 136-139, 144. DOI: 10.3969/j.issn.1000-5641.202092303
Online available: 22 January 2021

Abstract （244）

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Development opportunities for economic cooperation between China and Laos under the background of the Belt and Road Initiative

Vilaiphorn CHANTHANILEUTH, Ping QI

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 140-144. DOI: 10.3969/j.issn.1000-5641.202092307
Online available: 22 January 2021

Abstract （417）

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The impact of reviving the Maritime Silk Road on Egyptian-Sino relations

Bassem ELMAGHRABY

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 145-149. DOI: 10.3969/j.issn.1000-5641.202092308
Online available: 22 January 2021

Abstract （311）

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Inclusiveness, mutual learning, and win-win cooperation: The case of Chinese investment in the China-Pakistan Economic Corridor

Abbas SHAH, Chenmin YAO, Yanfu ZHU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 150-152, 158. DOI: 10.3969/j.issn.1000-5641.202092310
Online available: 22 January 2021

Abstract （299）

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Integrating the Maritime Silk Road with Sub-Saharan African Transport Corridors to enhance economic development

Kingsley Che CHENIKWI, Xuefeng WANG

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 153-158. DOI: 10.3969/j.issn.1000-5641.202092311
Online available: 22 January 2021

Abstract （256）

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The Belt and Road Initiative as a new source of impetus for South-South Cooperation through knowledge transfer: A case study of Chinese companies in Ghana

Thomas AMEYAW-BROBBEY

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 159-164. DOI: 10.3969/j.issn.1000-5641.202092312
Online available: 22 January 2021

Abstract （350）

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Thoughts on strengthening the exchange of people between Mongolia and China

Sumiya CHULUUNBAATAR, Lei WU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 165-169, 187. DOI: 10.3969/j.issn.1000-5641.202092315
Online available: 22 January 2021

Abstract （295）

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Djibouti and the Maritime Silk Road

Wei SUN

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 170-174. DOI: 10.3969/j.issn.1000-5641.202092316
Online available: 22 January 2021

Abstract （314）

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Maritime Silk Road: Influence of geopolitics

Chao Alexander GAO, Feng ZHU

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 175-178. DOI: 10.3969/j.issn.1000-5641.202092320
Online available: 22 January 2021

Abstract （389）

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Trade: Hard or soft infrastructure? China’s Maritime Silk Road Initiative and what it means for Kenya

Asenath MAOBE

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 179-183. DOI: 10.3969/j.issn.1000-5641.202092321
Online available: 22 January 2021

Abstract （447）

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Pakistan and China’s nexus of agricultural trade under the Maritime Silk Road

Ghulam Muhammad QAMRI, Bin SHENG, Yousaf LATIF, Adeeba SARWAR

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 184-187. DOI: 10.3969/j.issn.1000-5641.202092322
Online available: 22 January 2021

Abstract （280）

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Trade between Poland and China within the Belt and Road Initiative and 17 + 1 Framework： Opportunity and challenge

Natalia BORUCZKOWSKA, Yuna DI

Journal of East China Normal University(Natural Science) 2020, 2020 (S1): 188-192. DOI: 10.3969/j.issn.1000-5641.202092324
Online available: 22 January 2021

Abstract （478）

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