Table of Content

    25 March 2015, Volume 54 Issue 2
    The Relationship Between the Melted Mark of Short Circuited Arc and External Heat in Electrical Fire
    WANG Li;FANG Shitong;YU Shenghui;LIANG Dong
    2015, 54(2):  1-7. 
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    With the help of the powder X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy, the PSM and SSM were studied to develop the quantitative analyses and demonstrate the relationship between the phase transition of copper melted mark the external heat condition in electrical fire. It is found that it is different for the trend of the grain size with the heat treatment time between PSM and SSM, and the curves of the texture coefficient with the heat treatment temperature between PSM and SSM shows the respective  trend  obviously. The chemical composition, included mainly carbon, oxygen and copper. The ratios of oxygen for the PSM is about 6%, and the ratio of oxygen for the SSM is about 3% in deposition layer. The atomic ratio of oxygen has not changed very much basically in the melted mark substrate, and it is at around 3% both PSM and SSM. The external heat has a different influence on phase transition of PSM and SSM, and the microstructure could reveal clearly, therefore, it is possible to set up the quantitative analyses for short circuit melted mark.
    Research of Data Modeling for Microscopic Traffic Simulation Based on Lane-level Basic Network and Its Application
    HUANG Ming;ZHANG Xu;LI Erda
    2015, 54(2):  8-13. 
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    The requirement for data model in microscopic traffic simulation is analyzed, and the model, which is consists of basic network model, signal control scheme description model and traffic demand model, is constructed.Signal allocates access right of time, and signal groups describe access rules at intersections in signal control scheme description model. Traffic demand model contains traffic zones and OD matrix. Traffic zone delimits the origin node and destination node of OD matrix, while OD matrix delimits volumes on the network. The corresponding relationship between elements of this model and that of microscopic traffic simulation model is studied with VISSIM as an example. Data is extracted to generalize VISSIM simulation model which proofs the models feasibility for data extraction and exchange.
    Study on Alternate Double Loops LED Driver
    LI Shuran;CHEN Ming
    2015, 54(2):  14-18. 
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    LED is a very sensitive semiconductor lighting device that needs an advantageous driver. A new alternate double loops LED driver based on LM358 (which integrates two operational amplifiers) in line with the characteristics of LED is proposed. The driver demonstrates excellent output characteristics through both current and voltage control. The principle is discussed first and a Matlab simulation is conducted to analyze the control scheme in its amplitude frequency and phase frequency characteristic, verifying the stability of the scheme. Also its advantages and parameters calculation are discussed. The proposed scheme adopts buck topology and achieves alternate double loops control through LM358 which can accurately control the drivers output voltage and current. The Simulink simulation and experiment verify the availability and reliability of the proposed scheme.
    Damage Identification of Curtain Wall Cable Based on Sensitivity Analysis of Response Power Spectral Density
    CHEN Weihuan;DING Changyin;HE Bingquan;LIU Jike
    2015, 54(2):  19-23. 
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    Curtain wall cable is an important engineering structure. Aiming at the damage detection of curtain wall cable, finite element method was used for the forced vibration analysis of string structures. The dynamic response sensitivity with respect to the physical parameter, such as elemental cross-sectional area, was derived. The sensitivity of the response power spectral density with respect to elemental cross-sectional area under stationary random excitations is obtained using pseudo excitation method. Then finite element model updating method is adopted to identify the curtain wall cable damage. Numerical simulation shows that satisfactory identification results can be obtained from the power spectral density of response data of several accelerometers and the proposed method is insensitive to the measurement noise. It has the potential for practical application.
    A New Specific Combination Method of Wireless Communication Modulation Recognition Based on Clustering and Neural Network
    YANG Faquan;LI Zan;LUO Zhongliang
    2015, 54(2):  24-29. 
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    To improve the recognition rate of the signal, a modulation recognition method is proposed based on the clustering algorithm under the low SNR. The characteristic parameter of the signal is extracted by using a clustering algorithm, neural network is trained by using the algorithm of variable gradient correction BP so as to enhance the rate of convergence.The performance of recognition under the low SNR is improved,and the modulation recognition of the signal is realized based on the modulation system of the constellation diagram. Simulation results show that the recognition rate based on this algorithm is enhanced over 30% compared with methods of adopting clustering algorithm or neural network based on BP algorithm alone under the low SNR. The recognition rate can reach 90% when the SNR is 4 dB, and the method is easy to be achieved so that it has broad application prospect in the modulating recognition.
    Effect of Bond Length on the Plain Bar of Single Pull out Test
    YANG Yi;ZHANG Yafang ;LIU Hao;LIU Feng
    2015, 54(2):  30-35. 
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    A numerical code RFPA2D has been adopted to conduct numerical analysis on the impact of bond length on the plain bar. With the numerical mode, the entire damage process of the plain bar as being pulled out from concrete block and the corresponding AE result have been analyzed. To verify the numerical simulation results, a pullout test has also been carried out and corresponding acoustics emissions have been collected. The physical test has similar results compared with the numerical analysis. Both tests indicate that the peak pullout force also increased with increased bond length.
    Statistical Analysis of RPPA Data in Cancer Research
    YI Le;LUO Dongmei;QIN Yuehai
    2015, 54(2):  36-42. 
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    Protein expression data of The Cancer Genome Atlas, namely the Reverse Phase Protein Array data for statistical analysis, are adopted to mine hidden association information between cancer and genes, and to improve the efficiency of clinical diagnosis and to reduce the cost of inspection. Network structure of each group data and expression levels of different genes are gotten through the heat maps. And 5 genes which play an important role in protein expression levels for these 3 kinds of cancers are obtained by principal component analysis. Finally, the discriminant model based on the 5 genes for 3 kinds of cancer and the estimation of  the misjudgment rate are built by the back substitution method and cross-validation method. It is concluded that the network structure of the protein expression level for each kind of cancer is constructed respectively, 5 genes which play an important role in protein expression level are sought out, and the result of linear discriminant model is reliable.
    Generalized Dual Space Indicator Method for Inverse Scattering of Acoustic Waves in a Stratified Medium
    LIU Lihan
    2015, 54(2):  43-48. 
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    A generalized dual space indicator method is presented for inverse scattering of acoustic waves in a stratified medium.The method is based on the observation that the weighted integration of the measured scattered field can approximate the Greens function very well when source point of  the Greens function is inside the obstacle,but not so well when the source is outside the obstacle. An integral equation whose right-hand side is the Greens function with a source point from a searching region is set up. Then it is known that the norm of the solution of the integral equation has local maximum that lies inside the unknown obstacle, and the region which is surrounded by the local maximal points is exactly the region of obstacle. The most remarkable advantage of this method is that no knowledge of boundary condition is needed.
    Note on the Edge-Wiener Indices of a Class of Random Polygonal Chains
    WANG Hongyong,JIANG Qin
    2015, 54(2):  48-50. 
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    Edge-Wiener index is a new topological invariant which is used in the study of physicochemical properties of chemical compounds and is closely associated with the Wiener index-To investigate the related properties of a class of important polygon chains comprehensively, an explicit expression for the expected value of the Edge-Wiener indices of a class of random polygonal chains is given. For applications, the Polyphenyl chains which can achieve the maximum and minimum of the EdgeWiener indices is found. And some results that have been published in recent papers are revealed. Finally the asymptotic behaviour of EdgeWiener indices is also considered.
    Integrating Factors and Conservation Laws for Mechanical Systems with Non-Chetaev Nonholonomic Unilateral Constraints
    SHU Fangping;ZHU Jianqing;ZHANG Yi
    2015, 54(2):  51-54. 
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    In order to further study the conservation laws of nonholonomic mechanical systems, the method of integrating factors is applied to mechanical systems with non-Chetaev nonholonomic unilateral constraints, which establishes a new method to find the conservation laws of mechanical systems with non-Chetaev nonholonomic unilateral constraints. Firstly, the necessary conditions for the existence of the conservation laws of nonholonomic mechanical systems are studied. Secondly, the relation between the conservation laws and the integrating factors is established, then the generalized Killing equations which are used to determine the integrating factors can be presented. Finally, the conservation laws of non-Chetaev nonholonomic mechanical systems with unilateral constraints can be found. Also, an example is given to illustrate the application of the results. The results show that the method of integrating factors can be used to study the conservation laws of mechanical systems with nonChetaev nonholonomic unilateral constraints.
    Asymptotic Behaviors of Solutions for a Nonlinear Singular Parabolic Equation
    LIU Qiang;ZHANG Liwei
    2015, 54(2):  55-58. 
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    By compactness argument and a priori estimate technique, the asymptotic behaviors of solutions, as λ→0+and λ→+∞ respectively, for a nonlinear singular parabolic equation are studied, where λ is a parameter of this equation. And the convergence rates of solutions are established. A deep relation between the equation considered here and the evolutionary p-Laplace equation is revealed.
    On the Maximal Inequalities for the Arbitrary Identically Distributed Random Variables and Applications
    CHEN Chuanyong
    2015, 54(2):  59-61. 
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    Let {X,Xn,n≥1} be a sequence of identically distributed random variables (without any independence assumption) and denote Sn=∑ni=1Xi,n≥1. An upper bound for the distribution function of   max1≤k≤n |Sk| / n(1/p), with 0<p<1, is given. As an application, a sufficient condition for the existence of the r-th (r > 0) moments ofsup1≤k≤n |Sk| / n(1/p) is obtained.
    Transformation from α to β of Nucleation Mechanism of Montmorillinite Filled Isotactic Polypropylene Composites
    DAI Xin, ZHANG Zishou,CHEN Chunyan,LI Mei,MAI Kancheng
    2015, 54(2):  62-65. 
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    Montmorillontie (MMT) filled isotactic polypropylene (iPP) forms α-crystal. In this paper, β-MMT with β-nucleating surface supported by calcium pimelate (CaPA) was prepared through chemical reaction between Ca2+ and pimelic acid (PA). The results of FTIR spectroscopy and TGA analysis of β-MMT confirmed the formation of CaPA on the surface of MMT. The crystallization temperature, β-nucleating ability and the β-crystal content of β-MMT filled iPP composites were investigated by DSC and XRD analyses. It was observed that the crystallization temperature and intensity of βcrystal melting peak increased with decreasing MMT/PA mass ratio, indicating the enhanced β-nucleating ability. The XRD results showed that the β-crystal contents of β-MMT filled iPP composites increased with decreasing MMT/PA mass ratio. In addition, MMT filled iPP composites with β-crystal of 99% could be obtained by β-MMT prepared with MMT/PA mass ratio of 100. These results indicated that the β-nucleating agent supported on the surface of MMT particles could change from α- to β-nucleation in the MMT filled iPP composites.
    Preparation of CuMn2O4/NiMn2O4 Catalysts for Thermocatalytic Degradation of Methylene Blue Near  Room Temperature
    DING Feng;LUO Xuegang;ZHANG Sizhao;LIN Xiaoyan
    2015, 54(2):  66-71. 
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    A CuMn2O4/NiMn2O4  heatsensitive catalyst was prepared by a high temperature solid phase method. The product was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analysis (TGA), UV-Vis spectroscopy (UV-vis), and scanning electron microscopy (SEM). The thermocatalytic degradation behavior for methylene blue (MB) was investigated at near room temperature. The results showed that, when the system temperature was increased from 30, 35, to 40 ℃ at the initial concentrations of 30, 40, and 50 mg/L, their corresponding removal rates reached 68.35%, 79.64% and 88.89%, respectively. The optimal degradation rate was achieved in the conditions of the treatment time of 48 h, the initial concentration of MB at 30 mg/L, the dosage of 45 mg for thermal catalyst, and at 40 ℃ in dark. Besides, the degradation products were analyzed by gas chromatographymass spectrometer (GCMS). The result indicated that the main products were dichloromethane and toluene, confirming the true occurrences of the degradation for MB. In conclusion, the thermocatalytic degradation route under near room temperature may provide a potential method in the treatment for waste water in industry.
    Distribution and Source Analysis of PCBs in Ice Water During the Frozen Period at the Toudaoguai Section of Yellow River
    LI Hanqing;PEI Guoxia;ZHANG Qi;HAN Zhen;GAO Lihui
    2015, 54(2):  72-76. 
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    This study was conducted on basis of the measured data of polychlorinated biphenyl content in ice water during the frozen period, at the Toudaoguai section of Yellow river in 2012-2013. The distribution characteristics of polychlorinated biphenyl content and its origins were analyzed at this specific section in the frozen period. Results showed that: the ΣPCBs concentration in water is 10.19~5300 ng·L-1, and the average concentration is 31.87 ng·L-1; the ΣPCBs concentration in ice is 2.91~34.34 ng·L-1, and the mean one is 15.11 ng·L-1, the content of Low PCB is larger than the High PCB, which is in consistence with the practical situation that Low PCB was massively produced and used in our country. Compared to the corresponding period in 2011-2012, the content of Low PCB was increased by 65.7%, but, the High PCB one was lowered by 20.39%, the general content was enlarged by 28.96%. The PCBs content in Flow Ling period is the maximum one, and it becomes smaller and smaller in the frozen period, while depicts a slight inclination of increase in the Ice Melting period. The origins of PCBs in ice water during the frozen period are: electric insulating oil, paint additive and Bleaching industries.
    Determination of 12 Hydroxylated Polycyclic Aromatic Hydrocarbons in Sediment Samples
    TANG Nian;YUAN Ke;LI Li;ZHOU Yongyan;WANG Yu;LUAN Tiangang;WANG Xiaowei
    2015, 54(2):  77-82. 
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    A sample pretreatment method was developed for 12 hydroxylated polycylic aromatic hydrocarbons (OHPAHs) in sediment samples. The OHPAHs was extracted by accelerated solvent extraction (ASE) from sediment matrix and clean up by solid phase extraction (SPE), the target compounds were finally analyzed by GC-MS after derivatization by BSTFA. Several parameters, including the extraction solvent for ASE, alumina oxide sorbent for SPE and derivatization time that affected the proposed method, were optimized. The results showed that the LODs of the target analytes were ng·kg-1 level and the RSDs were acceptable (<10%) when using methanol as ASE extraction reagent at 60 ℃ for 60 min and alumina oxide as SPE sorbent. Moreover, the recoveries of the analytes were higher than 60% except for 9-hydroxy-phenanthrene (39.5%). The proposed method was applied to determine 12 hydroxylated PAHs in sediments of Humen estuary, south China and 10hydroxylated PAHs were detected with the concentrations ranging from 0.58 (4hydroxyphenanthrene) to 2.4 ng·g-1 (6-hydroxy-chyrene).
    Analysis of Pyrolysates from Fenugreek Absolute by On-Line Pyrolysis-Gas Chromatography /Mass Spectrometry
    YE Rongfei;CHENH Xia; SONG Senchuan ; LI Feng; HUNNG Fei ;REN Chenglong;SONG Huacan
    2015, 54(2):  83-88. 
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    Fenugreek absolute was pyrolyzed under helium atmospheres at 300, 400, 500, 600, 700 and 800 ℃, respectively. The pyrolysates were analyzed by online gas chromatography/mass spectrometry (GC/MS). The results showed that, first, eightysix constituents were identified, and the major of the pyrolysates were esters, acids, alcohols and alkenes. Second, the pyrolysates were almost same at lower temperature (300~500 ℃). Third, more and more benzene derivates were identified with higher percentage with increasing temperature (600~800 ℃). In addition, the flavor mechanism and the attribution of benzene compounds were investigated.
    Quantitative Analysis of Effective Constituents in Naoshuantong Capsule
    PENG Wei;SU Weiwei;XIE Chengshi;CHEN Si;YAN Fengxian
    2015, 54(2):  89-91. 
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    A HPLC method of quantitative analysis was established to determine Typhaneoside, Isorhamnetin-3-O-neohespeidoside, Paeoniflorin and β-Ecdysonein in Naoshuantong Capsules for improving its quality standard. The present study determined the four effective contents in twelve batches of the medicine and proved that the new-established method is simple, accurate, economical and practical. The study provides a new method for quality control of Naoshuantong Capsule.
    Fingerprints and Content Determinations of Four Active Components of  Tripterygium Preparations by UPLC
    DENG Jinbao ; XU Fangfang ;XU Peng;MAO Wei;DENG Yuanhui;LIU Bo
    2015, 54(2):  92-100. 
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    To establish fingerprints of  Tripterygium preparations from different manufacturers,and to simultaneously determine the contents of four active components by ultra performance liquid chromatography (UPLC),providing a rapid detection method for quality control of  Tripterygium preparations. UPLC separation was performed on a BEH Shield RP 18 column (2.1 mm×100 mm,1.7 μm) with a mobile phase of acetonitrile-water under gradient elution,the flow rate was 0.25 mL/min and the column temperature was 35 ℃,the detection wavelength was set at 220 nm. The similarity of UPLC fingerprints was evaluated by qualitative and quantitative analysis,respectively. The results showed that the fingerprints of  Tripterygium preparations from different manufacturers were found to be in great diverse,while the contents of four active components were significantly different. So, this method is specific,fast,and with good resolution for the determination of UPLC fingerprint of  Tripterygium preparations. The simultaneous determination of contents of four active components can be used for the quality control of  Tripterygium preparations to ensure the safety and utility in clinical medication.
    Optimization of Extraction Process of Chinese Herbal Compound Bao-Xie-Ning for Anti-Diarrhea in Infant
    LIU Jing;ZHOU Yingli;WANG Chanjuan;XU Yuehong;ZHANG Kejian;WANG Dongmei
    2015, 54(2):  101-105. 
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    The study is to optimize and establish the extraction process of the Chinese herbal Compound BaoXieNing used for Antidiarrhea in Infant. The process was optimized by taking the extraction percentages of evodiamine, rutaecarpine, eugenol, cinnamic aldehyde as the evaluation parameters, considering the concentration of ethanol (extraction solvent), liquidsolid ratio, extraction time, extraction times as the affecting factor, and the extraction process of BXN optimized by L9 (34) orthogonal design. The results show that optimum condition is achieved when the concentration of ethanol is 95%, liquid-solid ratio is 10 (V/m), the mixed herbs are extracted twice while 2 hours for each time. The established optimum extraction process is efficient for the extraction of BXN, and is a stable, economical and convenient method.
    Arbuscular Mycorrhizal Fungi Colonization and Spore Density in Mangrove Species and Their Influence Factors in Dongzhaigang Nature Reserve
    HU Wenwu;WU Yong;GUO Jianhua;PENG Xue;XIN Guorong;ZHONG Cairong
    2015, 54(2):  106-111. 
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    Arbuscular mycorrhizal (AM) fungi exist in the root of a variety of mangrove plants, but our current research has failed to explain the reason and situation of their existence. This study intended to explore the AM fungi status and their influencing factors in mangrove species in Dongzhaigang National Nature Reserve. 16 mangrove species were investigated for their AM colonization rate, rhizosphere soil AM fungi spore density and soil parameters. The results showed that 12 of the total 16 plant species existed AM colonization, among which Excoecaria agallocha, Clerodendrum inerme, Pongamia pinnata and Hibiscus tiliaceus showed higher colonization rate than others (above 55%). AM fungi spores were detected from all rhizosphere soil samples, and the average AM fungi spore density was 25.7±2.7 spores per 25 g air dried soil. One-way analysis of variance (ANOVA) revealed that AM colonization status was significantly different among different host plants. Tide level could also significantly influence AM colonization rate and spore density. Both AM colonization rate and spore density were significantly higher in high tide level than middle or low tide level, but no difference existed between middle and low tide level. Linear regression analysis showed that soil moisture content, electrical conductivity and available P content may be the main influencing soil factors of AM fungi in Dongzhaigang mangrove ecosystem.
    Genetic Diversity and the Genetic Relationship Among Wild Types of Prunus divaricata By Using ISSR Molecular Markers
    LI Ling;HUANG Zheng;CUI Dafang;WANG Yonggang;XU Zheng;HE Tao
    2015, 54(2):  112-117. 
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    This paper used ISSR Molecular Markers to study the genetic diversity and the genetic relationship among 40 types of Prunus divaricata which originated in Tianshan Mountain of China. The study of genetic diversity and the analysis of UPGMA cluster showed that the 40 types of P. divaricate have genetic diversity, the average diversity index (I) was 0.488, the genetic similarity coefficient (Hs) ranged from 0.504 to 0.851 with an average of 0.678, the genetic distance (GD) varied between 0.127 0 and 0.604 2, the number of alleles (Na) and effective alleles (Ne) was 1.908 and 1.571 respectively, and the population has a low genetic diversity because of the average Nei's gene diversity index and the average Shannons information index (I) was 0.17 and 0.22; The 40 types of P. divaricate can be classified into 4 groups from the clustering results of molecular markers, combined with morphological analysis. The results showed that the 40 types of P. divaricate can be divided into four varieties, which were included P. divaricata var. humila (N.R.Cui et L.Wang)D. F. Cui, comb. nov., P. divaricata var. nigrooarp (N. R.Cui et L.Wang) D. F. Cui, comb. nov., P. divaricata var. phoenicea (Z.Xu) D. F. Cui, comb. nov. and P. divaricata var. luteola (N.R.Cui) D. F. Cui, comb. nov..
    The Genesis of Graphites in Xiuyan Gravel Nephrite Jades and Its Constraint on Their Host Nephrite Jade Rocks
    ZHANG Yuefeng;QIU Zhili;PENG Shuyi;ZHONG Youping;LI Liufen;WU Mo
    2015, 54(2):  118-126. 
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    Graphites are widely generated in geological processes of magmatism, metamorphism and hydrothermal alteration & metasomatism, and considered to be an indicative mineral for these geological processes. Xiuyan nephrite jades (locally named Laoyu), especially gravel nephrite jades, in Liaoning province, commonly contain graphite as internal enclaves. The study of these graphites will contribute to understand the formation of their host nephrite jades and the relationship between graphite enclaves and their host nephrite jades. In this paper,microscopic observation, Raman spectra and X-ray single-crystal diffraction are used to study graphites in host nephrite jades from Xiuyan, Liaoning, and the genetic relationship between graphites and their host nephrite jades. The results show that crystalline graphites commonly occurred in three clustered patterns of stripped, star-like and nebulous, in their host nephrite jades, and contained 19.52%~23.00% graphites in rhombohedral polymorph. The crystallinity indexes of graphites range between 0.562~0.644, and calculated forming temperatures range between 454~623 ℃. The temperatures are identical to those for amphibolite facies, obviously higher than previously reported data of nephrite jades. These results infer that graphites and their host nephrite jades probably formed in different geological processes or periods. Combining field investigation, we think that graphites in Xiuyan gravel nephrite jades were probably the remnant minerals of primary regional metamorphism prior to their host nephrite jades-formation, and Xiuyan nephrite jades formed through multi-stage or multi-period metamorphic and hydrothermal metasomatism processes from Liaohe group primary strata such as graphite & calcite-containing marble, graphite-containing tremolite granulite, or tremolite marble.
    Comparative Analysis on Probability Distribution Models of Short-time Strong Rainfall in the Cities of Pearl River Delta
    CHEN Zishen;HUANG Qiang;LI Honghao;XIANG Jingjing
    2015, 54(2):  127-132. 
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    The probability distribution applicability of short-time strong rainfall for 18 cities in the Pearl River Delta were contrastively analyzed by Using GPD, GEV and Pearson-Ⅲ type probability distribution model, respectively. The main conclusions were reached in the following: ① The results of goodness of fit test using Anderson-Darling test, probability plot correlation coefficient (PPCC), Root Mean Square Error (RMSE) and Q statistic reflected that the GPD method is more suitable for the design quantile calculation of the extreme hydrological and meteorological events for the shorter fixed number of year of the observation sites; ② The shape parameters of the GDP models for the cities of Huadu, Guangzhou, Xinhui, Enping, Shunde, Zhongshan, Zhuhai and Shenzhen show that the occurrence probabilities of short-time strong rainfall are high, and the calculated the design precipitation intensity larger than that with GEV and P-III type models; ③ Referring to “near shortterm rainfall intensity hierarchies”standard, in the Pearl River Delta, the rainfall intensity in a period of 2 years can reach the torrential rain level, which is the main influence factor for urban waterlogging events.
    Differential Analysis of Accessibility for Different Transportation Network in Guangzhou
    LI Yu, ZHANG Yihan, LI Jiancheng
    2015, 54(2):  133-140. 
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    Most of previous studies about accessibility focused on single traffic mode. This paper takes the weighted average travel time as an indicator to analyze the accessibility differences by using ArcGIS for three different traffic modes. Different transportation networks, including metro, highways, normal roads and combined networks, show a similar pattern. The area with highest accessibility is in the central urban area with a developed traffic condition. The better accessibility areas extend from center to the north, east and south. Since the distribution and running speed are different in networks, the percentages of area with an accessibility coefficient less than 1 in metro, highways, roads and common integrated transport network are 87.59%, 58.18%,77.50% and 85.17% respectively. We also found that the difference of the average travel time is very large in the same district, e.g., the difference between the maximum and minimum average travel time is 79.85 min in Zengcheng and Conghua.
    Forecasting Evaluations of Water Resources under Climate Scenarios in the East River Basin
    DENG Xiaoyu;ZHANG Qiang;LI Jianfeng ;SUN Peng ;CHEN Xiaohong
    2015, 54(2):  141-149. 
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    The East River basin is the principle source of water supply for megacities in/in the vicinity of the Pearl River Delta. In this study, water resources during 2020-2070 are evaluated under different climate scenarios based on outputs of 5 GCMs. The climate scenarios are RCP8.5, RCP4.5 and RCP2.6. Besides, downscaling procedure was done based on observed data covering the period of 1960-2000. The period of 1960-2000 was taken as the base period. HSPF model was used in hydrological modeling. The results indicate that: ① The HSPF model performs well in the hydrological simulation practice with NASH coefficient of over 0.81,PBIAS and RSR less than 10% and 0.45. The scenarios can well mirror the annual distribution of meteorological variables. ② The precipitation and evaporation during 2020-2070 under the RCP2.6 and RCP4.5 scenarios increase and evaporation decrease under RCP8.5 scenario. ③ The period of 2020-2070 will witness increasing monthly streamflow and also high/low flow regimes. Besides, when compared to the base period, the period of 2020-2070 will witness increasing flooding days . Flood risk will be significantly enhancing.
    Assessing Hydrological Impact of Land Use Change in the Dongjiang River Basin
    LIU Jie; CHEN Xiaohong; XIAO Zhifeng;GUO Qingwei;WU Genyi;XU Zhencheng
    2015, 54(2):  150-157. 
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    A comprehensive watershed model—the Hydrological Simulation Program FORTRAN(HSPF) was set up and calibrated for the Dongjiang River basin, which was used to quantitatively predict runoff in response to possible future land use change, combining with a land use projection model(CA-Markov) and a daily rainfall stochastic simulation model. The calibration and validation of the HSPF showed a good fit and the calibrated model was applicable to simulating the monthly runoff in the Dongjiang River Basin. The future land use scenarios generated by CA-Markov model result in little change in total runoff but some noticeable changes in surface flow. Both high flow and low flow increase under the future land use scenarios, and high flow increases with the growth of urban construction land while low flow decreases. The run-off effects of land use change decreases with increasing rainfall, and increases with decreasing rainfall. The changes of total runoff due to land use changes are little under four rainfall scenarios, but while the changes of surface flow are significant. Simulation hydrological change by connecting a land use prediction model and a semi-distributed hydrological model can be a good decision support tool for water management at a basin scale and capable of long-term scenario-based assessments.