J* E* C* N* U* N* S*

Select

An SIS epidemic model driven by a class of truncated stable processes

ZHANG Zhen-zhong, ZHANG Quan, YANG Hong-qian, ZHANG En-hua

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 1-12,38. DOI: 10.3969/j.issn.1000-5641.2019.01.001

Abstract （485）

HTML （17）

PDF（pc）（479KB）（508）

Save

A susceptible-infected-susceptible (SIS) epidemic model driven by spectrally positive α-stable processes is considered. Firstly, the uniqueness and the existence of the global positive solution are proved. Next, by using Khasminskii's lemma and the Lyapunov method, conditions for the existence of a unique stationary distribution are given. In addition, the model is shown to be exponentially ergodic. Finally, conditions for extinction of the model are given.

Reference | Related Articles | Metrics | Comments（0）

Select

Estimation of loss reserves based on a hierarchical bayesian model

ZHANG Yi, LIU Zhi-qiang, ZOU Si-si, WEN Li-min

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 13-23. DOI: 10.3969/j.issn.1000-5641.2019.01.002

Abstract （370）

HTML （144）

PDF（pc）（370KB）（447）

Save

Traditional loss reserve models are mainly based on aggregate loss triangles, in which the entries are obtained by summations of individual loss data. The summation procedures inevitably cause wastage of information contained in the raw individual data. Though this method is simple, it results in a larger error in the estimate of loss reserves. Individual loss reserve models emerging in recent years have failed to consider dependencies between policies. This article assumes the existence of certain common random effects between policies in the same accident year. Thus, a hierarchical bayesian model is built for individual data loss reserves. Using the ideas of credibility theory, we get the credibility estimate of loss reserves in each accident year, and thus the total reserve. In addition, the estimation of structural parameters and development factors are discussed. And the statistical properties are derived for those estimators of structural parameters. Finally, a numerical example is given to show the calculations with our estimators, and simulations are done to compare the mean square of reserve estimator between an individual loss model and an aggregate data model.

Reference | Related Articles | Metrics | Comments（0）

Select

Lie symmetry analysis, Bäcklund transformation and exact solutions for a class of fourth-order partial differential equations

DAI Hui-ju, LI Lian-zhong, WANG Qi, SHA An

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 24-31. DOI: 10.3969/j.issn.1000-5641.2019.01.003

Abstract （533）

HTML （12）

PDF（pc）（293KB）（565）

Save

This paper investigates a class of variable coefficient partial differential equations. By using the homogeneous balance method, the Bäcklund transformation is obtained, which leads to exact solutions for the equation. By applying Lie symmetry analysis, the symmetries and vector field of the equation are obtained. Then, by means of a similarity transformation, the partial differential equations are reduced to ordinary differential equations. Solving the reduced equations, we investigate the exact solutions to the equations concisely using the power series expansion method.

Reference | Related Articles | Metrics | Comments（0）

Select

The upper semi-continuity of the random attractor of the plate equation with linear memory

WANG Yi, MA Qiao-zhen

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 32-38. DOI: 10.3969/j.issn.1000-5641.2019.01.004

Abstract （409）

HTML （14）

PDF（pc）（284KB）（426）

Save

Based on the existence of random attractors in the plate equation with linear memory and additive noise, the upper semi-continuity of the random attractor is proved when the coefficient of the noise term goes to zero.

Reference | Related Articles | Metrics | Comments（0）

Select

L(2, 1)-labelling of Halin graphs with a maximum degree of seven

CHEN Xiao-feng, WANG Yi-qiao

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 39-47,57. DOI: 10.3969/j.issn.1000-5641.2019.01.005

Abstract （515）

HTML （23）

PDF（pc）（613KB）（410）

Save

A Halin graph is a plane graph G=T ∪ C, where T is a tree with no vertex of degree 2 and at least one vertex of degree 3 or more, and C is a cycle connecting the leaves of T in the cyclic order determined by the drawing of T. After structural analysis of Halin graphs, we show that the L(2,1)-labelling number of every Halin graph G with a maximum degree 7 is at most 10.

Reference | Related Articles | Metrics | Comments（0）

Select

A co-modelling approach for cyber-physical systems with SysML/MARTE/pCCSL

HUANG Ping, DU De-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 48-57. DOI: 10.3969/j.issn.1000-5641.2019.01.006

Abstract （457）

HTML （20）

PDF（pc）（6122KB）（667）

Save

Cyber-physical systems (CPS) are multi-dimensional complex systems that integrate computing, networks, and physical environments. The modelling for such heterogeneous systems is actively researched. However, there still lacks a systematic approach to model characteristics of CPS, such as heterogeneity, uncertainty, hardware/software coordination, and Non-Functional Properties (NFP). In this paper, we propose a co-modelling approach that relies on SysML (System Modeling Language)/MARTE (Modeling and Analysis of Real-Time and Embedded Systems)/pCCSL (p Clock Constraint Specification Language) to model different aspects of CPS from different points of view, including structure, behavior, clock constraints, and NFP. The novelty of our approach lies in the use of pCCSL to specify the interaction and synchronization to explicitly model the logical consistency between models. Meanwhile, to capture characteristics of CPS, such as stochastic behavior and continuous behavior, we build upon some meta-models of SysML/MARTE. Finally, to demonstrate the feasibility of our co-modelling approach, we present various models of an energy-aware building as a case study.

Reference | Related Articles | Metrics | Comments（0）

Select

Recursive algorithm for NoGo based on value evaluation

GUO Qian-yu, CHEN You-guang

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 58-65. DOI: 10.3969/j.issn.1000-5641.2019.01.007

Abstract （790）

HTML （139）

PDF（pc）（1276KB）（938）

Save

First, this paper introduces the rules of the game NoGo. Next, we review current methods of artificial intelligence and their respective shortcomings. Then, the article shows an analysis of the game theory characteristics of NoGo and proposes a value evaluation function. Based on this function, a multi-layer recursive algorithm to the artificial intelligence of NoGo can be constructed, which addresses the problem of high complexity in time and space in the present algorithm. Finally, the paper demonstrates the capability of this algorithm and provides results that the program against with the famous open source software OASE-NoGo, which achieved a winning rate of more than 90%. In a typical situation, it demonstrates that the algorithm is better than existing algorithms in computing, and proves the feasibility and effectiveness of this method.

Reference | Related Articles | Metrics | Comments（0）

Select

Multi-strategy gravitational search algorithm based on dynamic grouping

ZHANG Qiang, WANG Mei

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 66-75. DOI: 10.3969/j.issn.1000-5641.2019.01.08

Abstract （388）

HTML （16）

PDF（pc）（430KB）（443）

Save

A multi-strategy gravitational search algorithm based on dynamic grouping is proposed in this paper. At the initial stage of the algorithm iteration, adaptive grouping strategies are used to optimize populations. Only the least-optimal individuals are updated in each group. The cloud model theory is used to improve the evolutionary behavior of the optimal individuals. In the later part of the algorithm iteration, the populations are divided into dominant and extension subgroups. The differential mutation operator is subsequently used to update the dominant subgroups to improve the precision and speed of the optimization. Tent chaos theory is used to update the extension subgroups to complete the individual variation. Typical complex function tests show that the algorithm has good convergence accuracy and computational speed.

Reference | Related Articles | Metrics | Comments（0）

Select

Program for calculating the integer order of Bessel functions with complex arguments

REN Hong-hong, GUO Ying-chun, WANG Bing-bing

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 76-82,92. DOI: 10.3969/j.issn.1000-5641.2019.01.009

Abstract （605）

HTML （20）

PDF（pc）（684KB）（512）

Save

Fortran source code for calculating the integer order of Bessel functions of the first kind with complex arguments is presented. The method is based on the backward recurrence relation of Bessel functions. Values of the Bessel function generated by our program are in-agreement with the values generated by Matlab to at least 12 significant digits. We use the program to calculate the integer order of Bessel functions of the first kind with pure imaginary arguments, provided by Xu Shiliang's Fortran algorithm assembly. The results show that the first 6 significant digits are accurate. We also analyze the algorithm for calculating Bessel functions with complex arguments, which use the infinite sum of the product of the real arguments of the Bessel function and the pure imaginary arguments of the Bessel function, provided by Xu Shiliang's algorithm assembly. The results show that this algorithm does not always get accurate values for Bessel functions with complex arguments. The reason lies with the fact that the term in the sum larger than the function value causes the loss of significant digits.

Reference | Related Articles | Metrics | Comments（0）

Select

Comparison of the efficiency of equilibrium and nonequilibrium molecular dynamic simulations of molecular solvation free energies

LI Peng-fei, WANG Mei-ting, MEI Ye

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 83-92. DOI: 10.3969/j.issn.1000-5641.2019.01.010

Abstract （486）

HTML （11）

PDF（pc）（492KB）（471）

Save

In this study, we used calculations to determine the solvation free energies of 13 side chain analogs of neutral amino acids in water to compare the performance of equilibrium and nonequilibrium molecular dynamic simulations on high-performance computers. We found that nonequilibrium molecular dynamic simulations have the same accuracy as equilibrium molecular dynamic simulations in calculations for solvation free energies. From the perspective of efficiency and computational cost, the nonequilibrium method is more efficient and requires less computational time.

Reference | Related Articles | Metrics | Comments（0）

Select

Preparation of photocatalytic materials MIL-125(Ti)/BiOI and photocatalytic performance study

HUANG Xian-zhi, PIAO Xian-qing, CAI Ya-guo

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 93-104,114. DOI: 10.3969/j.issn.1000-5641.2019.01.011

Abstract （594）

HTML （18）

PDF（pc）（7632KB）（596）

Save

With pentahydrate bismuth nitrate (Bi(NO₃)₃5H₂O), potassium iodide (KI), and MIL-125(Ti) as raw materials, ethylene glycol as solvent, and citric acid as the structural inducer, heterojunction structure light catalyst MIL-125(Ti)/BiOI was prepared through one-step coprecipitation. The effect of photocatalytic degradation of Rhodamine B in visible light was also tested. By a series of measurements, including XRD, PL, SEM, BET and UV-Vis, we researched the relationships between structure, morphology, spectrum and the catalytic performance of the catalyst. Furthermore, the catalytic mechanism was analysized via energy band structure. The results indicated that by adjusting the ratio of Ti/Bi, MIL-125(Ti)/BiOI has a good degradation effect on Rhodamine B under visible light radiation, which is stable and can be applied to industrial applications.

Reference | Related Articles | Metrics | Comments（0）

Select

Optimization of parallel method of moments based on KNL many-core processors

GU Zong-jing, ZHAO Xun-wang, LIU Ying-yu, LIN Zhong-chao, ZHANG Yu, ZHAO Yu-ping

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 105-114. DOI: 10.3969/j.issn.1000-5641.2019.01.012

Abstract （526）

HTML （10）

PDF（pc）（1340KB）（441）

Save

The parallel method of moments (MoM) is successfully optimized using the MPI+OpenMP hybrid programming strategy, based on the second-generation Intel Xeon Phi many-core processor platform, codenamed Knights Landing (KNL). Using OpenMP programming technology, the utilization rate of the CPU (Center Processing Unit) is increased, and the computing resources of KNL are fully utilized. The introduction of threads substantially reduces the inter-process redundant integrals in the filling matrix process. In order to give full play to the advantage of KNL's 512-bit vector width, the efficiency of the loop structure is further enhanced through vector optimization. For the matrix solution process, which typically requires intensive computation and high CPU utilization, MPI (Message Passing Interface) communication time is reduced and the solution process is accelerated by introducing an OpenMP programming strategy. Numerical results show that the efficiency of solving complex electromagnetic problems by parallel MoM is greatly improved through optimization on the KNL many-core processor platform.

Reference | Related Articles | Metrics | Comments（0）

Select

Node localization of wireless sensor networks based on the kernel matrix ISOMAP algorithm

YANG Hai, LI Bing

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 115-123. DOI: 10.3969/j.issn.1000-5641.2019.01.013

Abstract （381）

HTML （10）

PDF（pc）（536KB）（417）

Save

Position information is nonlinear in the node localization of wireless sensor networks (WSN). Based on the robust ability of multivariate linear regression of partial least squares (PLS), and in combination with nonlinear data dimension reduction of manifold learning, a novel kernel matrix ISOMAP (Isometric Feature Mapping) algorithm is proposed. Geodesic distances between nodes are used as a measure of dissimilarity, and the contribution rate is then used to find and delete the "short circuit" edge. The matrix constructed by a double-centered transformation and the kernel transformation trick is mapped to a high dimensional feature space; finally, the relative position is obtained by PLS. Compared with the traditional ISOMAP algorithm and the multidimensional scale method (MDS), simulation results indicate that the proposed algorithm has good topology stability, generalization properties, robustness, positioning accuracy, and lower computational complexity.

Reference | Related Articles | Metrics | Comments（0）

Select

Application of R language graphics in biological research

LAN Yang, HE Xiu, ZHU Cheng-xu, ZHANG Yu-juan

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 124-135,143. DOI: 10.3969/j.issn.1000-5641.2019.01.014

Abstract （860）

HTML （36）

PDF（pc）（2336KB）（863）

Save

The R programming language offers powerful statistical analysis, data processing, and visualization capabilities, which can run on Windows, Linux, and Mac operating systems; the software allows users to show scientific research data through graphics by writing new code or adjusting existing code. However, it is difficult to learn R's programming code and use R packages, so R is not commonly favored by novices in the scientific research community. Based on the context of bioscience fields and data from published papers, public databases, and the National Bureau of Statistics, this study demonstrates how to plot high quality maps, heat maps, functional networks, Venn diagrams, and column charts using R, R Studio, and R-packages. To facilitate the use of R, we offer detailed scripts for biological researchers. After comparing R with other graphing software, this study provides good examples and discussions of how to reasonably and intuitively present results in biological research. We hope R will become the preferred plotting tool for elementary biological researchers in their learning and research activities.

Reference | Related Articles | Metrics | Comments（0）

Select

Spatial difference and discussion of water-use efficiency in China under objective constraint

LIAO Yu-xin, ZHANG Yong, GU Run-zhu

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 136-143. DOI: 10.3969/j.issn.1000-5641.2019.01.015

Abstract （449）

HTML （11）

PDF（pc）（1230KB）（417）

Save

The proposal of the Water Saving Society (WSS) and the strictest water resource management system introduced clearer and stricter requirements for water use in China. To calculate the constraint of the set objectives on water use, this study defined Objective Constraint Strength (OCS) for water regulation, and further compared OCS of agricultural and industrial water-use efficiency for 31 provincial regions in China. The study also carried out scenario analysis on seven different types of areas and proposed advice on WSS construction.

Reference | Related Articles | Metrics | Comments（0）

Select

Comparison of growth and photosynthesis characteristics of native and exotic salt marsh vegetation under elevated temperature and waterlogging conditions

LI Shi-hua, XIE Li-na, CHEN Wei, FEI Bei-li, YUAN Lin, GE Zhen-ming

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 144-155. DOI: 10.3969/j.issn.1000-5641.2019.01.016

Abstract （417）

HTML （14）

PDF（pc）（2451KB）（562）

Save

Growth and photosynthesis characteristics of native Phragmites australis and exotic Spartina alterniflora, the dominant salt marsh species in China's coastline, grown under elevated temperature and waterlogging conditions, were investigated. The results showed that elevated temperature increased the shoot height, leaf area, maximum rate of photosynthesis, and the apparent quantum yield of P. australis under non-waterlogging (Non-W) and shallow-waterlogging (S-W) conditions. However, the effect was negligible for the growth and photosynthesis parameters of P. australis in deep-waterlogging (D-W) conditions. The shoot height of P. australis reached a maximum, but the leaf area was lowest in a D-W state, indicating morphological adaption to waterlogging. D-W conditions significantly decreased the photosynthesis and chlorophyll fluorescence parameters of P. australis during the middle and later growth periods, compared to Non-W and S-W conditions. Both temperature elevation and waterlogging increased the growth, photosynthesis and chlorophyll fluorescence parameters of S. alterniflora, and the degree of increase under elevated temperature was greater than that of P. australis. Differences in growth and photosynthesis of S. alterniflora between the waterlogging treatments were not notable throughout the growing period. Analysis of variance showed that the effect of elevated temperature on the eco-physiological characters of P. australis was season-dependent, and the impact of waterlogging treatment was more notable with some interaction between the treatments. The effect of temperature elevation on photosynthesis parameters of S. alterniflora was notable, but not for the waterlogging treatment. We suggest that anticipated climate warming and rises in sea level might be beneficial to the exotic marsh species.

Reference | Related Articles | Metrics | Comments（0）

Select

Variations in organic carbon and its impact on tidal creeks within vegetation communities in the coastal wetlands of the Yangtze Estuary

FEI Bei-li, XIE Li-na, LI Shi-hua, CHEN Wei, GE Zhen-ming

Journal of East China Normal University(Natural Sc 2019, 2019 (1): 156-165. DOI: 10.3969/j.issn.1000-5641.2019.01.017

Abstract （511）

HTML （18）

PDF（pc）（2309KB）（523）

Save

Tidal creeks are identified as an important pathway for carbon exchange between coastal wetlands and the adjacent environment. This study investigated the seasonal variations in dissolved organic carbon (DOC) and particulate organic carbon (POC) in tidal creeks within typical vegetation communities (Poaceae and Cyperaceae) in the coastal wetlands of the Yangtze Estuary. The results showed that during ebb the concentrations of organic carbon components changed gradually along the altitude gradient from high marsh to low-lying shallow water areas outside the creeks. Generally, spring tides increased the organic carbon abundance in both creeks, relative to neap tide. In the Poaceae creek, with high plant biomass and soil carbon stocks, the DOC concentrations were significantly higher compared to the Cyperaceae creek during ebb across all seasons. In contrast, the POC contents were lower in the Poaceae creek compared to the Cyperaceae creek. The results of this study indicated that the Poaceae creek functioned as a net export (source) of DOC throughout the year but as a net sink of POC, and the Cyperaceae creek functioned as a net source of organic carbon over all seasons.

Reference | Related Articles | Metrics | Comments（0）

Select

Convergence analysis of iterative methods for strictly sub-diagonally dominant linear equations

CAI Jing

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 1-6,55. DOI: 10.3969/j.issn.1000-5641.2019.02.001

Abstract （527）

HTML （18）

PDF（pc）（430KB）（547）

Save

The Jacobi iterative method, Guass-Seidel iterative method, and SOR iterative method are commonly used in solving linear equations. When the coefficient matrix of a system of linear equations is strictly sub-diagonally dominant, we demonstrate that the Jacobi, Guass-Seider, and SOR iterative methods are all convergent. By comparing the upper bounds of error for the three iterative methods, we show that the upper bound of error for the Guass-Seidel iterative method is minimal.

Reference | Related Articles | Metrics | Comments（0）

Select

Weight one Eisenstein series associated with imaginary quadratic fields

SHEN Li-chien

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 7-20. DOI: 10.3969/j.issn.1000-5641.2019.02.002

Abstract （449）

HTML （14）

PDF（pc）（396KB）（381）

Save

We consider a family of weight one Eisenstein series associated with the imaginary quadratic fields. The subspace of the Eisenstein series associated with the Kronecker symbol is characterized by the quadratic forms generated from the genus theory of Gauss; we will derive a family of identities connected with these quadratic fields.

Reference | Related Articles | Metrics | Comments（0）

Select

Conservation laws and self-consistent sources for a super-HU equation hierarchy

FANG Fang, HU Bei-bei

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 21-31. DOI: 10.3969/j.issn.1000-5641.2019.02.003

Abstract （343）

HTML （13）

PDF（pc）（289KB）（424）

Save

In the present paper, a super-HU hierarchy was constructed based on super-matrix Lie algebra and super-trace identity. In addition, an integrable super-HU equation hierarchy with self-consistent sources was established. Finally, we set up infinitely many conservation laws for an integrable super-HU equation hierarchy by introducing two variables F and G.

Reference | Related Articles | Metrics | Comments（0）

Select

Average homogeneous and non-homogeneous weighted receiving time in recursive weighted Koch networks

ALHADDAD Mansour A. A., MOHAMMAD Gareeb

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 32-48. DOI: 10.3969/j.issn.1000-5641.2019.02.004

Abstract （412）

HTML （12）

PDF（pc）（1284KB）（420）

Save

In this paper, we introduce the recursive homogeneous weighted Koch network model for real systems with a scaling factor t ∈ (0, 1) and the non-homogeneous model with scaling factors t, s∈ (0, 1) or t, r, s ∈ (0, 1). These models were constructed using the recursive division method and motivated by experimental study of aviation networks and metabolic networks. As a process of fundamental dynamics, we study the recursive homogeneous and non-homogeneous weighted Koch networks with a random walk; for all steps, the walker who is starting from an existing node moves uniformly to one of its nearest neighbors Γ(j) lying on the layers L_e, e=0, 1, …, m. In order to study homogeneous and non-homogeneous models, the recursive division method and singular value decomposition were used to calculate the sum of the mean weighted longest paths (MWLP) for all nodes absorbed at the target node placed in one of the merging nodes {p_i:i=1, 2, 3}. Finally, in a large network, the average weighted receiving time (AWRT) for homogeneous and nonhomogeneous models grows sub-linearly with the network's order.

Reference | Related Articles | Metrics | Comments（0）

Select

Borel directions of solutions of a second order linear complex differential equation

WEI Wen-long, HUANG Zhi-gang

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 49-55. DOI: 10.3969/j.issn.1000-5641.2019.02.005

Abstract （431）

HTML （16）

PDF（pc）（284KB）（413）

Save

In this paper, we consider the Borel directions of solutions of the differential equation f" + A(z)f' +B(z)f=0. By using Nevanlinna's value distribution theory and assuming that A(z) is extremal for Yang's inequality, we provide conditions for B(z) that guarantee that every non-trivial solution f of the equation is of infinite order; we also calculate the number of Borel directions of these solutions.

Reference | Related Articles | Metrics | Comments（0）

Select

Inverse completion for a class of Hamiltonian matrices

BAI Xiao-li, ZHANG Lan

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 56-62,68. DOI: 10.3969/j.issn.1000-5641.2019.02.006

Abstract （390）

HTML （12）

PDF（pc）（443KB）（373）

Save

In this paper, the inverse completion of a class of Hamiltonian matrices is studied by applying rank theory and invertible conditions for matrices. Taking advantage of the structural characteristics of Hamiltonian matrices, the sufficient and necessary conditions for the existence of solutions are proved and the expression of solutions are obtained. Furthermore, the conclusions are extended to anti-Hamiltonian matrices, and the corresponding results are obtained. Finally, some examples are used to verify the conclusions.

Reference | Related Articles | Metrics | Comments（0）

Select

Localized theorems of finite groups with M_p-supplemented subgroups

BAO Hong-wei, LI Feng-qing, ZHANG Jia, TANG Ju-ping

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 63-68. DOI: 10.3969/j.issn.1000-5641.2019.02.007

Abstract （378）

HTML （11）

PDF（pc）（281KB）（421）

Save

A subgroup H of G is M_p-supplemented in G, if there exists a subgroup B of G such that G=HB and TB < G for every maximal subgroup T of H with|H:T|=p^α. Based on the idea of localization, by using the M_p-supplemented properties of some primary subgroups to study the structure of finite groups, we obtained sufficient conditions for p-nilpotent and p-supersolvable groups.

Reference | Related Articles | Metrics | Comments（0）

Select

Dynamic routing algorithm based on local information in a free-scale network

HAN Ding-ding, LIU Kang, TANG Ming

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 69-76,96. DOI: 10.3969/j.issn.1000-5641.2019.02.008

Abstract （450）

HTML （17）

PDF（pc）（1002KB）（515）

Save

We proposed a packet routing algorithm with two tunable parameters, α and β, which control the routing preference of degree and queue length, respectively, based on local information in a scale-free network. By adjusting the parameters to change network transmission capability, we found an optimal combination of the two parameters.Other dynamic properties, including average packet travel time and traffic load were also studied. Simulation research showed that the proposed algorithm not only reducedpacket loss rates, but also improved transmission capability and alleviated traffic congestion. We also compared the algorithm with other classical routing algorithms, based on real networks, and the proposed algorithm also displayed good results.

Reference | Related Articles | Metrics | Comments（0）

Select

A Reference Model approach for developing agricultural big data infrastructures

ZHAO Zhi-ming, LIAO Xiao-feng, WANG Xiao-ling, RUAN Chun-sheng, ZHU Yi-feng, FENG Dong-sheng

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 77-96. DOI: 10.3969/j.issn.1000-5641.2019.02.009

Abstract （648）

HTML （33）

PDF（pc）（5811KB）（690）

Save

Big data infrastructures provide services for the management of data over the course of their lifecycle, and offer users the ability to effectively discover and access data for different application purposes. These emerging infrastructures essentially enable system-level data-centric research; third-party innovation, however, often requires data from different sources. The construction of big data infrastructures faces important interoperability challenges arising from the diverse nature of data acquisition, annotation, and identification performed in different research domains. Moreover, the evolution of different infrastructures is often driven by the specific interests of researchers, in their respective domains, and the constraints of legacy technology. The ENVRI Reference Model (ENVRI RM) is an output of the EU H2020 ENVRI and ENVRI PLUS project, targeting the aforementioned challenges in the context of environmental sciences by modeling environmental research infrastructures with a multi-viewpoints framework; these viewpoints include science, information, computation, engineering, and technology. Each viewpoint describes concrete aspects of a system definition and forms a mechanism to improve the interoperability across the whole system as well as alignment with existing legacy systems. The challenges encountered in the Shanghai Agricultural Big Data Infrastructures construction work are similar to those detected in the ENVRI RM, which provides an ideal place to test the generalizability of the ENVRI RM to other domains. Using the ENVRI RM as a reference, this paper presents an Agricultural Reference Model, which includes the five aforementioned viewpoints, but with consideration of the specifics of the agricultural domain, to address the problems encountered in revising and upgrading the Shanghai Agricultural Big Data Infrastructures. Two use cases are introduced to demonstrate its effectiveness. One is to improve the requirement engineering procedure with the community and role context captured using the Agricultural Reference Model. The other is to upgrade the large volume of existing systems to increase interconnections via the interoperability mechanisms provided by the Agricultural Reference Model.

Reference | Related Articles | Metrics | Comments（0）

Select

Non-orthogonal corrections to wave functions in perturbation theory

SHEN Jia-yin, XUE Xun

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 97-105,115. DOI: 10.3969/j.issn.1000-5641.2019.02.010

Abstract （546）

HTML （14）

PDF（pc）（534KB）（514）

Save

Time-independent perturbation theory is fairly accurate for the correction of non-degenerate energy levels, but its accuracy is not satisfactory for the correction of wave functions. After examining the derivation process of perturbation theory, it was found that the reason for the difference in precision may be related to the Orthogonality Assumption. The Orthogonality Assumption-an arbitrary-order modified wave function above zero order is orthogonal to the zero-order wave function-is a condition used in establishing perturbation theory. This paper explored the Orthogonality Assumption in detail and obtained a constraint condition on higher-order modified wave functions by using the normalized properties of the wave function; this condition implies that the accuracy at second-order and above is not suitable for use with the Orthogonality Assumption. It can be shown that without introducing the Orthogonality Assumption, the result of the energy level correction is exactly the same as that of the orthogonal situation, but the result of the modified wave function has a difference that cannot be ignored. This phenomenon can reasonably explain the previous accuracy problem. In this paper, the first three-order non-orthogonal corrective wave function of the one-dimensional charged harmonic oscillator system in the homogeneous electric field is taken as a specific example. By comparing the analytical solution of this system, it can be demonstarted that the non-orthogonal correction of the wave function has higher accuracy than the orthogonal correction. The paper briefly discusses generalization to the degenerate perturbation theory. Combined with recent progress on the Stark problem, it offers a possible method to check for correction of non-orthogonal perturbation.

Reference | Related Articles | Metrics | Comments（0）

Select

Research on parton fragmentation functions of protons

LI Pei-yu, RUAN Jian-hong

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 106-115. DOI: 10.3969/j.issn.1000-5641.2019.02.011

Abstract （546）

HTML （12）

PDF（pc）（460KB）（460）

Save

Parton distribution functions and fragmentation functions are fundamental to analyzing high energy experiments.The relationship between the proton valence quark distribution function q(x) and fragmentation function D(x) is analyzed. We find that the simple function D(x)=(1/6)q(x) for a valence quark is a good approximation to describe the available data. We set up a group of new parameterizations of fragmentation functions for protons. Differential cross section data were calculated and compared with recent research. We hope that our work can diminish uncertainties when fitting parton fragmentation functions of protons.

Reference | Related Articles | Metrics | Comments（0）

Select

Complexity of black holes in nonlinear electrodynamics

LI Li, DING Yu-chen, WANG Tao

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 116-121. DOI: 10.3969/j.issn.1000-5641.2019.02.012

Abstract （424）

HTML （17）

PDF（pc）（293KB）（435）

Save

Black holes usually have two horizons in nonlinear electrodynamics based on the Einstein gravity theory. Starting with the action and a spherical metric of general forms in this theory, we calculated the electric potential of the black hole as well as the action of the Wheeler-DeWitt patch. The action turned out to be equal to the electric charge multiplied by the potential difference between the inner and outer horizons. Following the conjecture of complexity-action duality proposed recently by Susskind et al., the action can be interpreted as the computational complexity of the quantum states on the Anti-de Sitter boundary. In the special cases of the Reissner-Nordstrom black hole and the Born-Infeld black hole, our general results agree well with the results published in the literature.

Reference | Related Articles | Metrics | Comments（0）

Select

A first principle investigation of organic-inorganic hybrid peroviskite (C₄H₉NH₃)₂PbBr₄

XIE Wei-jia, WANG Qian-qian, XIE Wen-hui

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 122-127. DOI: 10.3969/j.issn.1000-5641.2019.02.013

Abstract （486）

HTML （20）

PDF（pc）（773KB）（674）

Save

The structural and electronic properties of the two-dimensional (C₄H₉NH₃)₂PbBr₄ monolayer were investigated by employing first principle electronic structure calculations based on the density functional theory. The optical absorption properties were studied by further analyzing chemical bonding and orbital characteristics. In addition, the influence of a vertical electric field on the electronic structure was also investigated. The results demonstrate that there is a significant external electric field-driven energy gap modulation effect, and that the semiconductor energy gap should be closed when the external electric field is larger than 0.45 V/Å.

Reference | Related Articles | Metrics | Comments（0）

Select

An investigation of the invasive plants in Nanjing Botanical Garden Memorial Sun Yat-Sen

YIN Qian, WANG Hong-jiang, LIU Xing-jian

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 128-134,163. DOI: 10.3969/j.issn.1000-5641.2019.02.014

Abstract （437）

HTML （12）

PDF（pc）（1111KB）（461）

Save

In order to understand the status of invasive plants in Nanjing Botanical Garden Memorial Sun Yat-Sen, the species, origin, life form, frequency and damage of alien invasive plants were surveyed through routing and sampling. The results showed that there were 65 invasive plants in the botanical garden area; Compositae constituted the largest proportion, accounting for 32.31% of the total, followed by graminaceous plants, accounting for 9.23% of the total. Among the invasive plants, 7 species have caused serious harm, 44 species were introduced from America (the largest point of origin), and most were annual herbs (46.15%). Wasteland and meadows under poor management are the most vulnerable habitat types. The invasion of some species has correlation with the introduction of new plants in the botanical garden.

Reference | Related Articles | Metrics | Comments（0）

Select

The effect of dissolved silicic acid on circular motion behaviors in pennatae: A case study on diatom Navicula arenaria var. rostellata

WANG Feng, ZHAO Li-xia, ZHU Zheng, HU Wen-si, LIU Quan-xing

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 135-146. DOI: 10.3969/j.issn.1000-5641.2019.02.015

Abstract （550）

HTML （15）

PDF（pc）（1615KB）（499）

Save

Diatoms play an important role in the primary productivity of aquatic systems and in driving the global silicon and carbon cycles in biogeochemistry. Navicula (Navicula arenaria var. rostellata) is a widely distributed diatom species in polluted aquatic and coastal ecosystems. In this study, we treat Navicula as the research object, using f/2+Si culture medium 30 mg/L dSi concentration as a reference to set different dSi concentration gradients (1 mg/L, 15 mg/L, 30 mg/L, 60 mg/L, 120 mg/L, 240 mg/L); based on the Navicula experiments and tracking of cell trajectories and behavior analysis, we explore the effects of different concentrations of dSi on diatom movement behaviors and diffusion coefficients. We found that:Their trajectories display circular motion associated with stochastic disruption. The curvature of the circular arc remains unchanged, and the direction and speed of the motion change significantly at the reverse time point; when the angle is less than 90 degrees; moreover, the velocity decreases before and after the reverse. Their motions display ballistic behavior on short time scales, Brownian-motion on long time scales, and super-diffusion on intermediate time scales. Miniscule and high dSi concentrations effectively inhibit active dispersal, whereas low and intermediate dSi concentrations promote dispersal on diatom cells. Here, our study of individual movement behaviors on diatoms helps to improve our understanding of foraging strategy and aggregation behavior in diatom biofilms; in addition, it provides new ideas on the outbreak of algal bloom, the marine biofouling phenomena, and marine snow phenomena.

Reference | Related Articles | Metrics | Comments（0）

Select

Evaluation of ecosystem services for urban forests in Shanghai based on a distribution measurement methodology

HAN Yu-jie, SUN Wen, ZHANG Wen-wen

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 147-155. DOI: 10.3969/j.issn.1000-5641.2019.02.016

Abstract （431）

HTML （16）

PDF（pc）（1858KB）（472）

Save

Using continuous observation and the inventory system for forest ecosystems, according to the People's Republic of China standard LY/T 1721-2008 Specifications for assessment of forest ecosystem services in China, combined with forest resource monitoring data from 2016, this study assessed the value of forest ecosystem services in Shanghai. The results showed that the total value of forest ecosystem services in urban forests in Shanghai in 2016 was 12.58 billion yuan and mean value was 127.5 thousand yuan per hectare. The value of the eight service functions was distributed as follows:forest recreation (26.03%), atmosphere environmental purification (22.03%), carbon fixation and oxygen released (20.24%), water conservation (17.14%), biodiversity conservation (9.10%), soil conservation (3.53%), forest nutrition storage (1.84%), contribution of forest to prevent natural calamities(0.09%). From the results of this study, the value of forest recreation was the highest. Forest recreation, atmosphere environmental purification, carbon fixation and oxygen release, and water conservation were the main functions of urban forest services in Shanghai; These features play an important role in building a livable city and establishing "an ecological city".

Reference | Related Articles | Metrics | Comments（0）

Select

Determination of sulfonamides by ultra-high performance liquid chromatography with microextraction

LI Yi, ZHANG Yan, ZHANG Ya-ting, HE Pin-gang, WANG Qing-jiang

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 156-163. DOI: 10.3969/j.issn.1000-5641.2019.02.017

Abstract （410）

HTML （14）

PDF（pc）（950KB）（494）

Save

In this study, the development of an analytical method for the determination of chicken meat based on three-phase hollow fiber membrane microextraction ultra-high performance liquid chromatography (HF-LPME-UHPLC) was explored. A three-phase hollow fiber membrane microextraction system was developed to optimize the extraction conditions of HF-LPME:the extractant was n-octanol, the concentration of NaOH in the receiving phase was 200 mmol/L, the concentration of hydrochloric acid in the sample solution was 1.0 mmol/L, the concentration of Na₂SO₄ was 375 g/L, the extraction temperature was 30°, the stirring rate was 300 r/min, and the extraction time was 4 hours. Chicken meat samples were extracted and analyzed by UHPLC. Chromatographic analysis showed that the six sulfonamides reached baseline separation within six minutes. The linearity of the six sulfonamides in the mass range was good with a correlation coefficient of R² > 0.998 9, the enrichment factors ranged from 188 to 950 times, and the detection limit was 0.03~0.1 ng/mL (S/N=3). The recoveries of sulfonamides flagged in chicken were 85.2%~95.6% with relative standard deviations of 3.13%~4.33% (n=5) at a concentration of 50 μg/kg. The studied method is highly sensitive and reproducible, and can be used for the detection of sulfonamides in chicken.

Reference | Related Articles | Metrics | Comments（0）

Select

pH induced regulation of the morphology and properties of polybenzidine submicron rods

WANG Lin, ZHANG Yan-hui, Arzugul MUSLIM, Abida ABDUNAZAR, LAN Hai-die

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 164-173. DOI: 10.3969/j.issn.1000-5641.2019.02.018

Abstract （438）

HTML （10）

PDF（pc）（2576KB）（376）

Save

Polybenzidine was prepared using micelles of the triblock copolymer PnBA₂₈-b-PS₇₅-b-P2VP₁₀₄ as a template. The effects of different pH values on the morphology and properties of polybenzidine (PBZ) were investigated by regulating the pH value of the micellar solution of the templates. The molecular weight distribution and structure of the triblock copolymer PnBA₂₈-b-PS₇₅-b-P2VP₁₀₄ were determined by size exclusion chromatography (SEC) and nuclear magnetic resonance spectroscopy (¹H-NMR). The morphology and structure of the composites were characterized using a scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR). The electrochemical capacitance of the composites was evaluated by chronopotentiometry. The effects of the pH value on the morphology, structure and properties of PBZ were explored in this study. The PBZ particles were submicron and micron rods with uniform distribution and a smooth surface. PBZ rods obtained at pH=5 had an average diameter that ranged from several tens to 200 nm. The uniformity of particle morphologies was found to decrease with an increase in pH value; A electrochemical performance test showed that the specific capacitance of PBZ reached 339.06 F/g at pH=5.

Reference | Related Articles | Metrics | Comments（0）

Select

Analysis of the supply and demand of senior living facilities based on a refined population grid: A case study of Shanghai Pudong New District

ZHANG De-ying, ZHOU Yun-yun, LENG Xie, LI Long, ZHOU Jia-yuan, SHI Run-he

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 174-183. DOI: 10.3969/j.issn.1000-5641.2019.02.019

Abstract （474）

HTML （15）

PDF（pc）（4063KB）（497）

Save

The contradiction between supply and demand of urban senior living facilities, as a kind of basic public service resource, is especially severe. A refined population grid obtained by state-of-the-art geographic information technology is required to discover the spatial contradiction. This paper took Pudong New District of Shanghai as the research area. The contradiction between the supply and demand of senior living facilities was revealed based on a refined age population grid at a 160-meter resolution, considering the location of facilities, the number of beds, and the health condition of the elderly. The results show that:The refined age population grid can fully illustrate the spatial attributes of the aged population and can be matched with the distribution of beds in senior living facilities spatially, depicting both the supply and demand of senior living facilities visually. The number of beds in senior living facilities meets the requirements of the Shanghai government, namely no less than 3% of the local registered elderly population. The contradiction between supply and demand of senior living facilities depends on location. A distinctive shortage of supply exists in the central area. Smaller facilities and a dense elderly population reflect an urgent demand. Meanwhile, the situation is the reverse in the suburbs, there are multiple overlapping services of facilities. Some facilities in the outer suburbs are too remote to fit the required demand based on the distribution of the elderly population.

Reference | Related Articles | Metrics | Comments（0）

Select

Simulation analysis for remote sensing inversion of wavelength and water depth by the Fast Fourier Transform method

SHEN Si-min, ZHU Shou-xian, KANG Yan-yan, ZHANG Wen-jing, CAO Guang-song

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 184-194,208. DOI: 10.3969/j.issn.1000-5641.2019.02.020

Abstract （522）

HTML （14）

PDF（pc）（2538KB）（635）

Save

Using the difference in remote sensing reflectivity between wave crest and trough, wavelengths can be inversed by the Fast Fourier Transform (FFT) method to derive the nearshore water depth. Remote sensing images with higher resolution are generally thought to induce less error in marine information inversion. In this study, remote sensing images were replaced by elevation data from ideal equations and numerical simulations to study the effect of data resolution on wavelength inversions and water depths. The results show that low-resolution data result in significant errors in the wavelengths and water depths. But variations in resolution make no difference in reversing the wavelengths and water depths as they reach certain levels. The sub-image size in the FFT method was also studied by simulation analysis. Larger sub-images generate less error in wavelength inversion if the wavelength doesn't vary spatially. On uneven topography, errors from wavelength and water depth inversions are small if the sub-image size is 4-8 times the wavelength and not more than the topography variation; however, when the sub-image is too large or too small, the errors will increase.

Reference | Related Articles | Metrics | Comments（0）

Select

A study of the surficial suspended sediment concentration in response to typhoons in the Yangtze Estuary

WANG Hao-bin, YANG Shi-lun, YANG Hai-fei

Journal of East China Normal University(Natural Sc 2019, 2019 (2): 195-208. DOI: 10.3969/j.issn.1000-5641.2019.02.021

Abstract （516）

HTML （13）

PDF（pc）（4298KB）（515）

Save

Suspended sediment concentration (SSC) is an important index to measure water quality, and its variations have major influences on seabed erosion/accretion, biological primary productivity, and restoration/loss of land resources. To study the influence of typhoons on the SSC in the Yangtze Estuary, we used surficial SSC data collected at six gauging stations-namely Xuliujing, Qinglonggang, Gaoqiao, Hengsha, Sheshan, and Luchaogang-over the period from 2010 to 2014, as well as continuous data on wind speeds and wave heights over long time scales. The results indicated that wave heights and wind speeds during typhoons were on average 2.2 times and 1.7 times higher, respectively, than those before a typhoon occurred. The mean surficial SSC at the gauging stations also doubled, increasing from 0.32 kg/m³ before typhoons to 0.69 kg/m³ during typhoons. The SSC measured during typhoons was found to be 4 times larger than values observed during calm weather. The typhoons' influences on SSC, moreover, varied across different sections of the Yangtze Estuary. Influences measured at the Sheshan and Luchaogang stations in the outer estuary were the most significant, and the SSC at the two stations increased by 167.1% and 143.7%, respectively. However, the sensitivity of SSC to the typhoons was relatively minor in the inner estuary, where winds' influences were accordingly minimal. Based on long time scale data, the increase of SSC was moderate for wind scales 1-4, and the increase of SSC became evident above a wind scale of 5. Changes in wind speeds and wave heights, resulting from typhoons, were the most dominant factors attributing to the varation in surficial SSC. During typhoon season, the change of surficial SSC caused by typhoons is much greater than the change of surficial SSC due to tidal and runoff effects. This study is beneficial to the protection of coastal engineering during typhoons and has important implications for the study of interdisciplinary fields.

Reference | Related Articles | Metrics | Comments（0）

Select

Existence of weak solutions for a p-Laplace equation with gradient term

LI Zhong-qing

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 1-5. DOI: 10.3969/j.issn.1000-5641.2019.03.001

Abstract （453）

HTML （62）

PDF（pc）（489KB）（428）

Save

This paper is devoted to the study of a quasi-linear elliptic equation with gradient term, where the source term f lies in the space L¹. Using the relationship between the coefficient of the zero order term and the source term, the a priori L^∞ estimate and the existence of weak solutions are obtained.

Reference | Related Articles | Metrics | Comments（0）

Select

Pseudo-umbilical space-like submanifolds in locally symmetric pseudo-Riemannian manifolds

BAI Hui-run, LIU Jian-cheng

Journal of East China Normal University(Natural Sc 2019, 2019 (3): 6-12. DOI: 10.3969/j.issn.1000-5641.2019.03.002

Abstract （497）

HTML （247）

PDF（pc）（279KB）（364）

Save

In this paper, we study the pseudo-umbilical space-like submanifolds Mⁿ which are immersed into locally symmetric pseudo-Riemannian manifolds N_p^n+p. When Mⁿ is complete non-compact and has a parallel mean curvature vector field, a pinching theorem for the square length of the second fundamental form of Mⁿ is obtained. When Mⁿ is compact and has a parallel mean curvature vector field, then we prove that Mⁿ is totally geodesic.

Reference | Related Articles | Metrics | Comments（0）

Volumn Content