Table of Content

25 May 2017, Volume 56 Issue 3

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Research progress on LID caused by B-O defects and its suppression for B-doped p-type crystalline silicon solar cells

AI Bin;DENG Youjun

2017, 56(3):  1-7. 

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Although boron-doped p-type crystalline silicon solar cells have been firmly occupying the dominant share in PV market, the light induced degradation (LID) caused by boron-oxygen (B-O) defects greatly limits their development. Newly-developed B-O defects regeneration technology combining minority carriers injection and heating has the potential to completely solve the LID problems of boron-doped p-type crystalline silicon solar cells. Considering that the research work on LID and its suppression measure is of a great importance to improve long term stability of todays mainstream crystalline silicon solar cells, the authors review the recent research progress on LID and its inhibition method of boron-doped p-type crystalline silicon solar cells, and emphatically introduce the newly-developed B-O defects regeneration technology.

Diffraction of solitary wave by arc-shaped bottom-mounted porous breakwater

ZHANG Ao;HUANG Hua;ZHAN Jiemin;ZHU Menghua

2017, 56(3):  8-16. 

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Based on wave model and wave diffraction theory, the wave potential solutions to solitary wave diffraction by arc-shaped bottom-mounted porous breakwater are derived by applying the eigenfunction expansion approach, and accordingly the horizontal wave loads on breakwater and maximum solitary wave free surfaces are analytically calculated. The evaluating results demonstrate that the porosity of lateral surface of arc-shaped breakwater may lead in an obvious reduction in wave loads on breakwater and changes the distribution of maximum solitary wave free surfaces. Furthermore, the variation of incident wave angle, nonlinear influence parameter of wave, sea water condition, and breakwater structure geometry condition may have some influence on solitary wave effects on breakwater. Compared with small amplitude wave theory, it is known that in certain shallow water conditions the results of maximum dimensionless wave forces and wave free surfaces from solitary wave theory are obviously larger than those predicted by small amplitude wave theory for shallow water, it denotes that solitary wave theory can reflect shallow water wave nonlinear effects.

The minimum lifting speed and pressure loss of the natural gas hydrate in the seabed

CHEN Hao;FU Laiqiang;Lv Bin;WU Wenke ;HUANG Junming

2017, 56(3):  17-25. 

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According to the correlation properties of natural gas hydrate, several main methods of exploitation of natural gas hydrate are compared and summarized. Based on the current theory on hydraulic lifting process of the natural gas hydrate, the minimum lifting speed of the natural gas hydrate particles is studied, and the minimum velocity was calculated by using the theory of the minimum velocity of hydraulic lifting with the natural gas hydrate particles. The theoretical modeling of the pipeline transportation system of the hydraulic lifting system is carried out, and used to study the effects of particle size. The particle diameter is studied, and compared with that on the pressure drop of gas hydrate in the pipeline system.

Noether-Mei symmetry and conserved quantity for dynamical systems with non-standard Lagrangians

SONG Jing;ZHANG Yi

2017, 56(3):  26-30. 

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This paper focuses on studying the Noether-Mei symmetry and the conserved quantity for dynamical systems with non-standard Lagrangians (exponential Lagrangians and power law Lagrangians). Firstly, The definition and the criteria of Noether-Mei symmetry for dynamical systems with non-standard Lagrangians are given. Secondly, The conditions that Noether-Mei symmetry leads to Noether conserved quantity or Mei conserved quantity and the form of conserved quantities are put forward. And four theorems for Noether-Mei symmetry and conserved quantities are established. Two examples are given to illustrate the application of the results.

A method of using IMSL Fortran numerical libraries in Fluent UDF

HU Wenqing;ZHAN Jiemin

2017, 56(3):  31-35. 

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UDF can greatly extend the functions of Fluent, is widely used in various types of Fluent calculation. IMSL is a set of mathematical and statistical libraries, with high efficiency, powerful performance, and simple application. A method is proposed to implement IMSL numerical libraries in UDF by compiling the Fortran program that calls IMSL as a dynamic link library and calling the dynamic link library in UDF. At the same time, an example is given to generate cnoidal wave in a numerical flume. It provides technical support for the realization of simpler, faster and more natural UDF programming with the advantages of IMSL, which greatly improves the compiling ability of complex UDF and enhances the computing power and application range of Fluent.

The counting formula of the perfect matchings of three types of special graphs

TANG Baoxiang;REN Han

2017, 56(3):  36-40. 

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Perfect matching counting problems graph has been proven to be NP-hard. To get the number of perfectly matched general graph is very difficult. The issue has important applications in protein structure prediction, crystal physics, quantum chemistry and computer science. The research on this issue has very important theoretical and practical significance. The counting formula of the perfect matching for graphs 3-nT₄, 5-nT₆and 2-2nQ_2×2 are obtained by applying differentiation, summation and re-recursion . This provides the theory support for the application of perfect matching in graph.

New method for cumulative distribution of scale-free network

WANG Xiaomin;YAO Bing

2017, 56(3):  41-45. 

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By applying algorithm method, the maximal planar network with scale-free properties is employed. The cumulative degree distribution and edge-cumulative degree distribution are computed, and the equivalence between them is testified. Besides, the new statistical index, namely, the mix cumulative distribution between edge and vertex on the basis of different mixed method is provided. A conjecture: If the mixed mode is linear, the mix cumulative distribution is equivalent to cumulative distribution is proposed. This conjecture makes a contribution to discussing scale-free network by applying all-round and multi-angle standpoint.

Optimization of collaborative filtering algorithm based on DAG Spark scheduling

LIAO Bin;ZHANG Tao;YU Jiong;GUO Binglei;ZHANG Xuguang;LIU Yan

2017, 56(3):  46-56. 

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The scale effect of big data has brought great challenges to data storage, management and analysis. And the high efficiency and low cost big data processing technology has become a hotspot research in academia and industry. In order to improve the efficiency of collaborative filtering algorithms, the implementation of the algorithm under the MapReduce architecture is decomposed in order to analysis the defects of the algorithm. For the Spark suitable for the iterative and interactive tasks, this paper presents the methods to improve the execution efficiency from the MapReduce platform to the Spark platform. The implementation flow of the algorithm in Spark is designed, and efficiency is improved by parameter adjustment and memory optimization. Experimental results show that: based on spark DAG scheduling, the algorithm can reduce more than 65% HDFS I/O operations and enforce the efficiency and energy efficiency were increased by nearly 200% and 50%.

Existence of weighted pseudo anti-periodic solutions to some neutral differential equations with piecewise constant argument

LIN Quanwen;ZHUANG Rongkun

2017, 56(3):  57-65. 

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By means of weighted pseudo anti-periodic solutions of relevant difference equations, the existence for weighted pseudo anti-periodic solutions of differential equations with piecewise constant argument is studied. The conditions of existence and uniqueness for the weighted pseudo anti-periodic solutions are presented.

Small amplitude limit cycles for two classes of Liénard systems

XIONG Feng;HUANG Wentao

2017, 56(3):  66-70. 

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The number of limit cycles for classes of Liénard systems (m=6, n=8) and (m=8, n=6) in the neighborhood of the origin is studied. It is proved that the two systems can generate 9 and 8 limit cycles in a sufficiently small neighborhood of the origin, respectively. It is the first time that  lower bound estimations of H(6,8)and H(8,6) are obtained, namely H(6,8)≥9, H(8,6)≥8.

The pinched theorems of hypersurfaces with constant mean curvature in unit spheres

WANG Fen;WU Xueling

2017, 56(3):  71-77. 

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The constant mean curvature hypersurfaces in unit sphere S_n+1 are considered. Under the hypothesis that the second fundamental form is constant or not, two important pinched theorems, which generalized corresponding results of Cheng (1996) and Xu et al (2011), are obtained.

The structure and properties of ZnS films prepared by chemical bath deposition

LI Zhong; HUANG Saihao;HONG Ruijiang

2017, 56(3):  78-84. 

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ZnS thin buffer layers were prepared by chemical bath deposition (CBD) process. The structures and optical properties of the films were studied systematically based on the chemical reaction principle. The results demonstrated that the thickness of ZnS film increased with the increase of deposition time, while the optical transmittance and the band gap decreased. The minimum E_g was determined to be 3.74 eV. The surface roughness of the as-deposited films remained a low level, of which value remained between 6~9 nm. As the concentration of the reactant increased, the optical transmittance increased first and then decreased. When the concentration of the reactants were too high or too low, the deposition reaction shifted to homogeneous reactions and impurities emerged on the surface of the films, resulting in inhomogeneous films. The optimized concentrations of ZnSO₄, SC(NH₂)₂ and NH₃·H₂O were 0.03, 0.4, 4.0 mol/L, respectively. The single-phased ZnS films were homogeneous and compact with the optical transmittance over 70% at the wavelength of 450~900 nm.

Chiral transition mechanism and water solvation effect of leucine molecules based on the amino proton transfer bridge

ZHAO Xiaobo;LI Chenjie;WANG Zuocheng;YU Xiaoji;YAN Hongyan;YANG Xiaocui;TONG Hua

2017, 56(3):  85-92. 

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The title reaction mechanism was explored by using the B3LYP density functional theory, the MP2 method of perturbation theory and smd model method of self consistent reaction field theory. The study of reaction channels showed that there are two channels a, b in the chiral transition reaction, and in the one the proton is transferred from one side to the other of chiral carbon with only the amino as a bridge, in the other with carbonyl and amino N as the bridge successively. The molecular structure analysis showed that the sevenring structure in the transition state aTS2·2H₂O is almost coplanar and each hydrogen bond angles of the seven-ring structure approach straight angle. Calculations of potential energy surface pointed out that the channel a is the dominant reaction channel and the free energy barrier of the rate-determining step is 249.5 kJ·mol^-1, which is caused by the transition state with proton migration from chiral carbon to amino nitrogen. Moreover, with consideration of two water molecules as H transfer media and with inclusion of the water solvation effect of the continuous medium model,, the free energy barrier of the rate-determining step is reduced to 113.2 kJ·mol^-1 and the reaction rate constant is 5.85×10^-8 s^-1, and the water solvation effect enables the energy barrier of the amino heterogeneous reaction increased from 13.4 kJ·mol^-1to 19.3 kJ·mol^-1. Therefore, water solvation effect can hinder the heterogeneous reaction of non proton transfer, and the interaction of the catalytic action of water molecules and water solvation effect can cooperatively reduce the proton transfer reaction energy barrier to a large degree.

Geotechnical engineering properties of the solidified sludge soil landfilled in Fuyong Shenzhen, China

LIN Shujiong;CHEN Jianshang;RAN Mengjiao;ZHANG Chengbo

2017, 56(3):  93-99. 

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The Fuyong sludge landfill site is located in the middle of the extension area of Shenzen International Airport, where it is going to build the T4 terminal. There is a great amount of solidified sludge soil landfilled in this site, which is a difficult problem for airport foundation improvement. In order to find out the geotechnical engineering properties of the solidified sludge soil, experiments including component analysis，microstructure observation，laboratory soil tests and in-situ tests were performed in this study. The results showed that the solidified sludge soil contained flake clay mineral particles, unshaped hydrated calcium silicate (CSH), needle like ettringite and loose structure organic matters; there were a lot of voids between the soil particals including macrovoid(1~6 μm) and microvoid; the solidified sludge soil had characters of low density, low soil particle density, high water content, high void ratio, high liquid limit and high plastic limit; the vane shear strength of the soil was 13.8~23.7 kPa and its strength increased greatly with the increase of the consolidation stress; the characteristic value of foundation bearing capacity was 78.9 kPa and the deformation modulus was 4.1 MPa, but the compression coefficient of the remolded soil was 3.073 MPa-1.

The secondary metabolites and bioactivities of mangrove endophytic fungus Aspergillus sp. 5Y in Yangjiang

LI Haibin;LAN Xiong;LIU Ting;GUO Junxin;HUANG Huarong;ZHANG Kun

2017, 56(3):  100-104. 

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The secondary metabolites of mangrove endophytic fungus Aspergillus sp.5Y was studied in this work.The chemical constituents were isolated and purified through silical gel,Sephadex LH-20,ODS-C₁₈ columnchromatography and HPLC and identified through IR,UV, mass anylysis and NMR specctroscopy. Five compounds were isolated from secondary metabolites of mangrove endophytic fungus Aspergillus sp.5Y and their structures were identified as 6-epi-ophiobolin P(1),strobilactone A(2),penicisochroman E(3),asperterpenol B(4),and (E,E')-6-(6′, 7′-dihydroxy-2′,4′-octadienoyl)-strobilactone A(5).Compound 1,4 have a good inhibition on α-glucosidase,IC₅₀values of (600.13±10.3) μmol/L,(9.57±0.) μmol/L respectively, which provides a certain theoretical data for researching and developing oral hypoglycemic drugs

Notch1 activation protects against triptolide-induced oxidative damage and apoptosis in hepatocytes

XIONG Zhewen;WANG Li;KONG Jiamin;WANG Wenwen;CHENG Yisen;SHEN Feihai;HUANG Zhiying

2017, 56(3):  105-118. 

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Triptolide (TP), the predominant active component of the traditional Chinese herb Tripterygium wilfordii Hook f. (TWHF), has been shown to exert multiple pharmacological effects. However, the clinical applications of TP are limited by its severe adverse effects, especially hepatotoxicity. The aim of this study was to investigate the potential protective effects of Notch1/NF-E2-related factor 2 (Nrf2) signaling on TP-induced hepatotoxicity. In the present study, TP caused oxidative stress and cellular apoptosis in Chang liver cells, which were accompanied by inhibition of the Notch1 activation signal. In addition, the activation of Notch1 by Jagged1 protected against TP-induced cytotoxicity, whereas the inhibition of Notch1 by DAPT or Notch1 siRNA increased the damage. We also found that activation of Notch1 upregulated Nrf2 and heme oxygenase-1 (HO-1) expression and that the inhibition of Notch1 resulted in the opposite effect. Interestingly, a reduction in Nrf2 almost eliminated the protective effect conferred by Jagged1, which indicated that Nrf2 was essential in the protection against TP-induced hepatotoxicity through the activation of Notch1. Overall, these results suggested that Notch1 signaling ameliorated the detrimental effects of TP by decreasing oxidative stress and downregulating apoptosis, and that the Nrf2 signaling pathway was a key downstream mediator of this effect.

Protective effects of Ophiopogonis japonicas extract on experimental type 2 diabetic rats

LI Jing;SU Weiwei;WANG Yonggang;PENG Wei;WU Zhong;LI Peibo

2017, 56(3):  119-124. 

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The aim of the present study is to investigate the protective effects of Ophiopogonis japonicas extract on experimental type 2 diabetic rats. The high-fat diet and low-dose streptozotocin (STZ) induced type 2 diabetic model in rats was used to observe the effect of Ophiopogonis japonicas extract on blood glucose level, oral glucose tolerance, insulin sensitivity, glycogen content in liver and skeletal muscle, urinary protein excretion and histopathological changes of pancreas. Results showed that Ophiopogonis japonicas extract could significantly lower the blood glucose levels and the AUCs during oral glucose tolerance test, improve insulin sensitivity, increase glycogen contents in liver and skeletal muscle, reduce urinary protein excretion, lower the kidney weight/body weight ratio and alleviate histopathological changes of pancrea occurred in diabetic rats by comparison with untreated diabetic rats. In conclusion, Ophiopogonis japonicas extract exerts remarkable protective effects in experimental type 2 diabetes mellitus, thus justifying its traditional usage.

Automated parameter optimization of distributed hydrological model for watershed flood forecasting

CHEN Yangbo;XU Huijun;LI Ji

2017, 56(3):  125-133. 

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The theory of automatic parameter optimization of the distributed hydrological model, including parameter's physical meaning, uncertainty, sensitivity and determinability, is presented in this paper. An automatic parameter optimization method based on Particle Swarm Optimization is proposed for the Liuxihe Model in watershed flood forecasting. This method is validated in the Wujiang Catchment in southern China and shows the advantages of high optimal performance, high computational efficiency, and good convergence. The Liuxihe Model based on the automatic parameter optimization method is more efficient.

A spatial clustering method fusing multiple algorithms for area feature

YANG Jie ;ZHANG Xinchang;HE Xianjing

2017, 56(3):  134-139. 

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Each spatial clustering algorithm has its own advantages and disadvantages. Spatial clustering algorithms can be improved and optimized through the fusion of the algorithms advantages. A spatial clustering method fusing multiple algorithms for area feature is proposed in this paper. This method optimizes the initial cluster centers of K-means algorithm by using genetic algorithm and other optimization algorithms, selects the k value of K-means algorithm by using a fast clustering algorithm density-based, and then obtains spatial clustering results with improved K-means algorithm. It improves the genetic algorithm which is easy to be affected by the initial population and has low efficiency. The experimental results indicate that the method is steady, and is more efficient and accurate compared to the traditional algorithm.

Urban expansion simulation and analysis based on CA model

ZHANG Yihan;XU Xiaocong;LIN Shengjie

2017, 56(3):  140-147. 

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In order to understand the urbanization process, logistic regression is introduced to mine the conversion rules of urban development. The rules are input into cellular automata (CA) model to simulate the urban development process of Foshan city. Experiments show that urbanization process is the core part in the development of Foshan city. The source of urban land comes from farmland, forests and other types of land (including orchards and ponds, etc.). In the simulation result, the overall accuracy and Kappa coefficient can reach 93.7% and 0.86, respectively. By using landscape indices, Foshan city will become more and more aggregative with the maximum patch index increase. It was found that there are 191 km² of farmland changed into urban land in the scenarios of urban prior development, accounting for 27% of all the farmland (706 km²). In the scenarios of farmland protection and forest protection, farmland and forest can be better protected, but urban expansion will occupy other types of land use to solve the problem of lacking enough land use for urban expansion. It is found that the spatial variables have remarkable corridor effect on urbanization by analyzing the relationship between proximity variables and urban land uses.

Micro-fabric characteristics of pyrite generations and their implications for genesis of Yunfu pyrite deposit, Qinzhou-Hangzhou metallogenetic belt，South China

GUO Xiaoyu;ZHENG Yi;ZHOU Yongzhang;NIU Jia;YU Pengpeng

2017, 56(3):  148-157. 

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Yunfu pyrite deposit is a large-scaled deposit，located in the southern section of Qinzhou-Hangzhou Metallogenetic Belt. Ore textures in the Yunfu pyrite deposit can be classified into four types, including the banded, disseminated, massive and veiny. The specimens and microscopic observation show that banded ores suffered the subsequent crumpled structures, the massive ores are composed of two different particle sizes of pyrite, and the pyrite vein cut across all above-mentioned ores. The SEM (Scanning Electron Microscope) coupled with EDS (EnergyDisperseSpectroscopy) measurements are carried out to yield the micro-fabric characteristics of all four types of pyrite. The pyrite grains in the banded ores present as cube euhedral crystal with the growth layer developed, implying that the crystal grows accompanying with multiple layer accumulation. The granularity of pyrite in the disseminated ores is commonly bigger than in banded ores, but the growth layer is inferior to the latter. The pyrite grains in the massive ores contact closely with conchoidal fracture developed on the surface, and therefore their crystal edges are difficult to be distinguished. The particle size of pyrite in the veiny ores is the largest among the four types of ores. The crystal shape presents as hypidiomorphic-xenomorphic implicating the limited growth space. It is conclude that the Yunfu pyrite deposit was developed with two main stages of mineralization, including an earlier exhalative sedimentary mineralization overprinted by subsequence metamorphism and deformation. The exhalative sedimentary stage is presented by the formation of banded and disseminated pyrites, whereas the later stage of hydrothermal superposition formatting is characterized by massive and veiny pyrites.

Effects of full biodegradable mulch film on soil moisture, temperature, nutrient and growth of  Prunus armeniaca

LING Hongbo;YU Ruide;LU Shan

2017, 56(3):  158-164. 

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Field experiments were conducted to study the effect of biodegradable film on the soil properties (moisture, temperature, and nutrients) and the growth of Prunus armeniaca (base diameter, new shoots, and leaf) during April to June in Tulufan, Xinjiang. The results showed that: ① the application of biodegradable film brought a significant effect on soil moisture and temperature, but not on soil nutrients. Soil water increased by 3.3%, 7.08% and 12.6% at the depth of 0＜H≤20 cm, 20＜H≤40 cm and 40＜H≤60 cm from April to June. The average temperature of soil at the depth of 0＜H≤60 cm in April increased by 1.5 ℃, while they relatively dropped at the depth of 0＜H≤20 cm in May and June when the air temperature was high. Film coating can benefit soil fertility, but the soil of experimental zone was still relatively poor. ② Film coating can significantly accelerate the growth of Prunus armeniaca, e.g. the trees have stronger stems (the average basal diameter of Ⅰ, Ⅱ, Ⅲ diameter class increased by 11.86%, 9.84% and 11.80%), larger leaves (the median dimension was more than 6 ×4cm), and heavier leaves (one hundred leave mass increased by 111.69%, 5.11% and 17.56%, respectively, for Ⅰ,Ⅱ, Ⅲ diameter class). ③ The full biodegradable membrane can regulate the soil moisture and temperature, and hence benefits the growth of Prunus armeniaca. The biodegradable film should be applied generally to improve the water resources utilization and agricultural production efficiency in the apricot cultivation.