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25 January 2020, Volume 2020 Issue 1 Previous Issue    Next Issue

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Mathematics

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Normal families of meromorphic functions and omitted functions YANG Qi, YANG Jinhua 2020, 2020 (1):  1-6.  doi: 10.3969/j.issn.1000-5641.201811043 Abstract ( 560 )   HTML ( 228 )   PDF (607KB) ( 216 )   Save 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. References | Related Articles | Metrics

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Analysis and application of exponential degradation paths with random failure thresholds GUAN Qiang, FU Zhiliang 2020, 2020 (1):  7-15.  doi: 10.3969/j.issn.1000-5641.201811040 Abstract ( 512 )   HTML ( 296 )   PDF (1065KB) ( 230 )   Save 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. References | Related Articles | Metrics

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The polar form of hyperbolic commutative quaternions KONG Xiangqiang 2020, 2020 (1):  16-23.  doi: 10.3969/j.issn.1000-5641.201911001 Abstract ( 433 )   HTML ( 189 )   PDF (656KB) ( 92 )   Save 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. References | Related Articles | Metrics

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An algorithm for finding all polynomial solutions of nonlinear difference equations Jiangtao YU, Yinping LIU 2020, 2020 (1):  24-39.  doi: 10.3969/j.issn.1000-5641.201811037 Abstract ( 487 )   HTML ( 244 )   PDF (1210KB) ( 172 )   Save 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. References | Related Articles | Metrics

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I-convexity and Q-convexity of Orlicz-Bochner function spaces with the Luxemburg norm DONG Xiaoli, GONG Wanzhong 2020, 2020 (1):  40-50.  doi: 10.3969/j.issn.1000-5641.201811042 Abstract ( 1423 )   HTML ( 178 )   PDF (608KB) ( 122 )   Save 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. References | Related Articles | Metrics

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Topological graph passwords based on the gracefulness of disconnected graphs with circles MU Yarong, LIU Xinsheng, YAO Bing 2020, 2020 (1):  51-57.  doi: 10.3969/j.issn.1000-5641.201811045 Abstract ( 396 )   HTML ( 165 )   PDF (959KB) ( 82 )   Save Graph labeling is an important branch of graph theory. We use disconnected graphs to start our study, and show that disconnected graphs G = (C4, Kr)∪∪t=1kKm,nt and G = (C4, Kr)∪K1,n∪∪t=1kTt allow graceful labelings. Algorithms can be used to provide a theoretical basis for proving the application of disconnected graphs to networks. References | Related Articles | Metrics

Physics and Electronics

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Atomic distortion in CrN: A first-principle investigation WANG Qianqian, ZHAO Zhenjie, LI Xin, XIE Wenhui 2020, 2020 (1):  58-66.  doi: 10.3969/j.issn.1000-5641.201922002 Abstract ( 433 )   HTML ( 190 )   PDF (816KB) ( 202 )   Save 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. References | Related Articles | Metrics

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Study on the covariant chiral effective field theory of vector meson WANG Yan, YANG Jifeng 2020, 2020 (1):  67-75.  doi: 10.3969/j.issn.1000-5641.201922007 Abstract ( 446 )   HTML ( 190 )   PDF (607KB) ( 80 )   Save 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. References | Related Articles | Metrics

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The complexity of Kerr-AdS black holes DING Yuchen, WANG Tao 2020, 2020 (1):  76-82.  doi: 10.3969/j.issn.1000-5641.201922004 Abstract ( 464 )   HTML ( 216 )   PDF (533KB) ( 292 )   Save 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. References | Related Articles | Metrics

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Novel polymer semiconductor films and related field effect transistor devices YE Jianchun, ZHOU Lizhao, LI Wenwu, OU-YANG Wei 2020, 2020 (1):  83-92.  doi: 10.3969/j.issn.1000-5641.201922006 Abstract ( 454 )   HTML ( 172 )   PDF (1121KB) ( 308 )   Save 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. References | Related Articles | Metrics

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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 2020, 2020 (1):  93-102.  doi: 10.3969/j.issn.1000-5641.201922005 Abstract ( 363 )   HTML ( 99 )   PDF (1118KB) ( 150 )   Save 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. References | Related Articles | Metrics

Ecological and Environmental Sciences

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Performance of lime-based algae control in urban landscape water ZHOU Yunchang, HE Yan, CHEN Jinghan, HUANG Minsheng 2020, 2020 (1):  103-109.  doi: 10.3969/j.issn.1000-5641.201831012 Abstract ( 392 )   HTML ( 14 )   PDF (947KB) ( 208 )   Save 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. References | Related Articles | Metrics

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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 2020, 2020 (1):  110-122.  doi: 10.3969/j.issn.1000-5641.201831013 Abstract ( 532 )   HTML ( 14 )   PDF (734KB) ( 101 )   Save 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. References | Related Articles | Metrics

Estuary and Coastal Research

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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 2020, 2020 (1):  126-138.  doi: 10.3969/j.issn.1000-5641.201841031 Abstract ( 594 )   HTML ( 17 )   PDF (997KB) ( 255 )   Save 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. References | Related Articles | Metrics

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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 2020, 2020 (1):  139-149.  doi: 10.3969/j.issn.1000-5641.201841035 Abstract ( 504 )   HTML ( 17 )   PDF (1233KB) ( 124 )   Save 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. References | Related Articles | Metrics

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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 2020, 2020 (1):  150-158.  doi: 10.3969/j.issn.1000-5641.201841032 Abstract ( 514 )   HTML ( 13 )   PDF (962KB) ( 177 )   Save 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. References | Related Articles | Metrics

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Review of estuarine and coastal environmental monitoring technologies GU Jinghua, GE Zhenpeng, WANG Jie 2020, 2020 (1):  159-170.  doi: 10.3969/j.issn.1000-5641.201841037 Abstract ( 685 )   HTML ( 19 )   PDF (839KB) ( 277 )   Save 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. References | Related Articles | Metrics