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Table of Content

    25 December 2008, Volume 36 Issue 12
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    Architecture & Civil Engineering
    Nonlinear Wind-Induced Vibration Response of Cable-Membrane Structures
    Wei De-min Shui Yuan
    2008, 36(12):  1-6. 
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    As a new long-span space structure type, the cable-membrane structure is sensitive to wind due to its light weight and flexibility. Thus, the wind load is generally taken as the control load in the design of cable-membrane structures. In this paper, the free vibration of a practical cable-membrane structure is analyzed by using the finite element program, and the wind-induced vibration response of the structure is theoretically analyzed by using a self-developed program. In the analyses, the influences of some basic parameters, such as the wind direction, the wind velocity and the membrane prestress, on the wind-induced vibration response are considered. The results indicate that the natural frequency of the cable-membrane structure significantly increases with the membrane prestress, and that the wind velocity is closely related to the wind-induced vibration response.

    Numerical Analysis for Low-Cyclic Loading Test of Shear Walls Based on OpenSEES
    Han Xiao-lei Chen Xue-wei Dai Jin-hua Cheang Jack He Wei-qiu
    2008, 36(12):  7-12. 
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    In order to reveal the seismic performances of shear walls with different structures, the frame-supported shear wall structure of the Garden Hotel in Guangzhou was used as the research object to perform low-cyclic loading tests in different reinforcement and construction.conditions. Then, the shear-wall nonlinear analysis program SWNA was secondarily developed based on OpenSEES and MVLEM, and was used to numerically simulate the low-cyclic loading plastic of shear walls. The results indicate that the proposed numerical method macroscopically simulate the elastic- behaviors of shear walls in terms of the shifting of natural axis, the shear deformation, the local plastic state and the collapse mechanism, and that MVLEM is suitable for the global elastic-plastic analysis and the seismic performance assessment of high-rise buildings because it saves the calculation time cost due to its low consumption of degree of freedom for the simulation of shear wails.

    Statistical Analysis of Strengths of Concrete and Steel Bar After High-Temperature Treatment
    Wu Bo Liang Yue-huan
    2008, 36(12):  13-20. 
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    Based on the statistical analysis of a lot of domestic test data on the strengths of normal-strength concrete and steel bars after high-temperature treatment, the mean values and variances of the relative residual strengths of the above-mentioned materials treated at different temperatures are obtained, and the corresponding normal distribution test is carried out. Afterwards, the quantitative relationships between the temperature and the mean value as well as the value with a guarantee rate of 95% are modeled. The results indicate that the relative residual compressive strength of concrete, the relative residual yield strength of hot-rolled bar and the relative residual ultimate strength of prestressed reinforcement all accord well with the normal distribution, and that, with their high accuracy, the proposed quantitative models provide the basis for the reliability evaluation of reinforced concrete structures after fire.

    Eccentric Compressive Behavior of Rectangular Concrete-Filled Steel Tube Columns with Binding Bars
    Long Yue-ling Cai Jian
    2008, 36(12):  21-27. 
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    The uniaxial eccentric compressive experiments of nine rectangular concrete-filled steel tubular stub columns, seven with and two without binding bars, were carried out. The effects of the eccentricity ratio and the horizontal spacing of the binding bars on the eccentric compressive behaviors of the columns were also analyzed. The results indicate that （ 1 ） the setting of binding bars improves the ductility of the columns and delays the local buck- ling of steel tubes; （2） the eccentric bearing strength of the columns decreases with the increase in eccentricity ratio ; and （3） the ductility of the columns with the same eccentricity ratio increases with the decrease in binding bar spacing. Moreover, the numerical results of bearing strength accord well with the experimental ones, while the resuits obtained based on the domestic design codes are much lower than the experimental ones.

    Parameter Analysis for Mechanical Properties of Steel-Reinforced Concrete Transfer Girders with Inner Steel Truss
    Yang Chun Wu Yi Cai Jian Chen Qing-jun Su Guo-wei
    2008, 36(12):  28-33. 
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    In this paper, the mechanical properties of steel-reinforced concrete transfer girders with inner steel truss which are affected by the angle of steel diagonal members, the ratio of bottom longitudinal reinforcements and the ratio of web reinforcements, etc. , are analyzed by means of the finite element method, and the corresponding force transfer mechanism is investigated. The results show that （ 1 ） the rigidity and limited bearing capacity of the transfer girders increase with the angle of steel diagonal members; （2） as compared with horizontal steel ties, steel diagonal members play a more important role in the force transfer; （3） as horizontal tension members greatly enhance the rigidity, ultimate the bottom longitudinal reinforcements working bearing capacity and ductility of transfer girders at a reinforcement ratio of less than 1.18% ; （4） the increase of web reinforcement ratio results in a significant enhancement of the ductility of transfer girders; （5） the transfer girders exhibit a strut-and-tie force transfer mode; and （6） the cross section of the concrete diagonal strut, a kind of fish-bellied member, is big in the middle while small at the two ends.

    Reliability Evaluation of Existing Frame Structure Based on Partial Coefficient Method
    Huang Yan-sheng Deng Hao Luo Ren-zhi
    2008, 36(12):  34-37. 
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    In order to evaluate the reliability of existing frame structures , a simplified fully-stochastic process model is adopted and the characteristics of structural resistances and loads are considered to establish a reliability appraisal formula for existing frame structures based on the partial coefficient method. Then, on the premise of maintaining the reliability of the structures, the calibration method of target reliability specified in the current design codes is employed to deduce some calculation formulas of the partial coefficients for both optimum load and resistance at different target periods of usage. Finally, by developing a program, the corresponding partial coefficients as well as the earthquake reduction factors for different target periods of usage are calculated. It is indicated by example that the proposed reliability appraisal formula can be conveniently applied to the reliability evaluation of existing frame structures.

    Automatic Switching System for Connection of Sensors Based on DataTaker Collectors
    Su Cheng Tan Lin Xu Yu-feng Pan Zhi-gang Chen Kuan-de Li Jing
    2008, 36(12):  38-42. 
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    In order to overcome the high cost and low efficiency of the conventional data acquisition systems for structure monitoring of long-span bridges, an automatic switching system is proposed for the connection of sensors based on DataTaker collectors. In the proposed system, the conventional direct connection between sensors and collectors is changed into an indirect connection through hubs and controllers, and the automatic switching between the hubs and sensors is implemented via the controllers excited by the digital signals output from the DataTaker collectors. Thus, the data from different sensors are effectively collected. Laboratory tests demonstrate that the proposed system is of high reliability and good stability. Moreover, the application of the system to the stress monitoring of a large-span arch bridge shows that the automatic switching system with good practicability effectively reduces the cost of stress measurement and improves the efficiency of data acquiring, data saving and transmission.

    Simulation System of Urban Water Supply Network Based on Virtual Reality
    Chang Kui Gao Jin-hang Yuan Yi-xing Wu Wen-yan
    2008, 36(12):  43-46. 
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    In order to establish a simulation system of the urban water supply network based on virtual reality, the running conditions of the network are simulated in a 3 D scene. In the simulation, first, an engineering database of the water supply network is built to ensure the accuracy of the 3D simulation model. Next, a 3D model of the urban water supply network is established based on the 3 D models of the valves and pipes constructed via MultiGen Crea- tor, and is then driven by Vega to implement the scene simulation of the running conditions using VC ＋ ＋ MFC and EPANET software package. The results indicate that the established simulation system based on the virtual reality directly displays the information of the urban water supply system, and that it well simulates the topology linkage as well as the running conditions, overcomes the limitation of the traditional geographic information system and is of higher precision and greater reliability.

    Calculation Model of Air Temperature Considering Heat Exchange Due to Vertical Turbulence and Horizontal Air Flow
    Zhang Lei Meng Qing-lin
    2008, 36(12):  47-51. 
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    In order to calculate the air temperature of the near surface layer in urban environment, the surface layer air was divided into several layers in the vertical direction, and some energy balance equations were developed for each air layer, in which the heat exchange due to vertical turbulence and horizontal air flow was taken into account. Then, the vertical temperature distribution of the surface layer air was obtained through the coupled calculation using the energy balance equations of underlying surfaces and building walls. Moreover, the measured air temperatures in a small area （with a horizontal scale of less than 500m） and a large area （with a horizontal scale of more than 1000m） in Guangzhou in summer were used to validate the proposed model. The calculated results accord well with the measured ones, with a maximum relative error of 4. 18% in a small area. It is thus concluded that the proposed model is a high-accuracy method to theoretically analyze the urban heat island and the thermal environment.

    Environment Science & Technology
    Degradation of Formaldehyde in Dielectric Barrier Discharge Plasma Reactor
    Chen Li Dai Wen Yan Zong-cheng Wang Hong-lin Cheng Bei-bei
    2008, 36(12):  52-55. 
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    This paper deals with the energy consumptions for the formaldehyde discharge （DBD） plasma reactors respectively with tube and flat pIate types. It degradation in two dielectric barrier aims to reveal the influences of discharging voltage, initial formaldehyde mass concentration and residence time on the degradation rate of formaldehyde. Experimental results indicate that （1） the energy consumption in the fiat-plate reactor （12. 8Woh/m3） is far below that of the tube reactor （55.0 Woh/m3 ） ; （2） the degradation rates of formaldehyde in both the tube and the flat-plate reactors greatly increase with the discharging voltage, then the increase degrees become low at the voltages of 11 kV and 18 kV, respectively ; concentration and then decreases, and （3） the degradation rate at first increases with the initial formaldehyde mass but it continuously increases with the extension of the resistance time.

    Experimental Investigation of Toluene Degradation by Photocatalysis Coupled with Dielectric Barrier Discharge
    Huang Bi-chun Yang Yue Zhang Xiao-ming Ye Dai-qi
    2008, 36(12):  56-60，69. 
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    This paper deals with the degradation of toluene gas by the photocatalysis coupled with dielectric barrier discharge （DBD）. It investigates the effect of the photocatalyst TiO2 driven by the DBD on the conversion rate of toluene at variable energy density, gas flow, discharge time and inner electrode diameter. The results show that （ 1 ） photocatalyst TiO2 improves the conversion rate of toluene and the selectivity of the products ; （2） when the energy density increases to 1000J/L, the conversion rate of toluene increases to 88.0% and the CO2 productivity to 39% ; （3） with the increase of gas flow, the conversion rate of toluene decreases; （4） the conversion rate of toluene increases rapidly in the first 5 minutes of discharge, then remains constant 10rain later; （5） the conversion rate of toluene at first increases and then decreases with the increase of inner electrode diameter; and （6） there is an optimal diameter （0. 80 mm） of inner electrode for toluene degradation because the carbon balance remains constant at a certain inner electrode diameter.

    Experimental Investigation of Chemically-Enhanced Phosphorus Removal with Adsorption-Biodegradation Process
    Hu Yong-you Luo Xiao-xiao Cheng Jian-hua Luo Gang
    2008, 36(12):  61-65. 
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    Aluminum sulfate （AS） and polyacrylamide （PAM） were used as the flocculants to remove phosphorus from the influent of Unit B in an adsorption-biodegradation （AB） process in laboratory scale. Then, the influences of flocculant dosage on the removals of total phosphorus （TP）, chemical oxygen demand （COD）, ammonia nitrogen （NH4＋ -N） and turbidity were analyzed, and the optimal dosage was determined. Finally, the relationship between the chemically-enhanced process and the biological process in terms of total phosphorus, COD, NH4＋ -N and turbidity removals were evaluated. The results indicate that （ 1 ） the compound of AS and PAM is effective in removing the TP in the influent of Unit B; （2） with the addition of 9. 5 mg/L AS （calculated with Al2O3 ） and 0. 05 mg/L PAM, the average removal efficieneies （REs） of TP, COD, NH4＋ -N and turbidity respectively reach 89. 2% , 37. 7%, 2. 41% and 71.6% ; （3） when adding AS and PAM, the REs of TP, COD and turbidity in the aeration process all increase except for the RE of NH4＋ -N ; and （4） although the postpose flocculation process is more effective in removing TP, COD and turbidity than the simultaneous one, the latter is more suitable for the chemically-enhanced phosphorus removal with AB process because the former needs additional sedimentation equipment.

    Biological Nitrogen Removal in Integrated Oxidation Ditch with Side-Channel Separator
    Zhou Shao-qi Wang Ping
    2008, 36(12):  66-69. 
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    At present, the Integrated Oxidation Ditch has become a research hotspot in the environmental protection field due to its small space occupancy and simple process. In this paper, a side-channel-separator Integrated Oxidation Ditch was used to treat the municipal sewage and to perform the biological nitrogen removal. In the experiment, the influent CODCr ranged from 200. 00 to 400. 00 mg/L, the content of NH4＋ -N was rapidly increased from 1.24 to 39.72 mg/L, the effluent CODc~ was kept at less than 15.00mg/L, and the effluent content of NH4＋ -N was generally kept at less than 2. 00 mg/L, showing a stable NH4＋ -N removal efficiency. Furthermore, the effects of alkalinity and CODCr/NH4＋ -N mass ratio on the biological nitrification process were analyzed, and some suggestions were proposed for promoting the denitrification efficiency.

    Contents and Leaching Characteristics of Heavy Metals in Aluminum-Anodizing Sludge
    Chen Yong-song Zhou Shao-qi
    2008, 36(12):  70-74,84. 
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    In this paper, the basic physicochemical properties such as the water content, the ash content and the pH value of 7 sludge samples collected from different aluminum-anodizing plants were analyzed, and the chemical compositions of the samples, as well as the contents and leaching characteristics of the heavy metals in the samples, were investigated. The results show that （1） all aluminum-anodizing sludge samples are slightly neutral to mild basic with more than 50% Al2O3; （2） the total contents of Cu, Pb, Zn, Ni, Cd and Cr in the 7 sludge samples are of similar distribution; and （3） the contents of Cu, Zn, Ni, and Cr are relatively higher than those of Pb and Cd. Moreover, leaching toxicity tests indicate that the aluminum-anodizing sludge is nonhazardous and the heavy metals in it are significantly different in leaching behaviors, possibly due to their total contents and to the final pH value of the leachate as well.

    Numerical Evaluation of Spatial Structure of Suspended Bio-Carriers
    Jiang Fan Chen Wei-ping Li Yuan-yuan
    2008, 36(12):  75-79. 
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    Suspended bio-carriers are important functional materials for the moving-bed bio-film reactor. In order to evaluate and optimize the spatial structure of suspended bio-carriers, the internal fluid dynamic characteristics of the moving-bed bio-film reactor loaded with suspended bio-carriers are analyzed via the dynamic numerical simulation coupling the dynamic mesh model with the two-phase flow model. Calculated results show that the coupled simulation technology helps to describe in detail the movement of suspended bio-carriers in the moving-bed bio-film reactor, and to obtain the quantitative distributions of the flow parameters such as pressure, velocity and gas holdup at each moment. The feasibility of applying the gas holdup and surface shear stress to the evaluation of the spatial structure of suspended bio-carriers is finally discussed.

    Forecasting of Effects of New Secondary-Fibre Paper Mill on Regional Water Environment
    Hou Yi Liu Ming-you Li You-ming Wang Jiang-lei
    2008, 36(12):  80-84. 
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    On the basis of the wastewater disposal evaluation of secondary-fibre paper mills in Yihuang County, Jiangxi, China, and by taking a planned secondary-fibre paper mill with an annual production of 100000 ton as the example, the effects of wastewater disposal on the water environment are investigated via modeling and forecasting, with CODCr and BODs as the control factors. The results show that secondary-fibre paper mills can be properly construtted in Yihuang because the wastewater disposal of the planned paper mill only slightly affects the regional water environment of the Yihuang River.

    Biological Engineering
    Optimization of Laccase Production from Geotrichum candidum and Decoloration of Azo Dyes by Laccase
    Yin Liang Chen Zhang-he Zhao Shu-jin
    2008, 36(12):  85-90. 
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    A fungus producing laccase was screened from dyeing wastewater and was identified as Geotrichum candidum （ G. candidum） M3. Then, the production conditions of laccase from G. candidum M3 and the decoloration ability of laccase for azo dyes were investigated. The results show that （ 1 ） glucose and ammonium chloride are respectively the best carbon and nitrogen sources for the production of laccase from G. candidum M3 ; （2） the optimal contents of glucose, ammonium chloride, guaiacol and copper sulfate for culturing laccase are respectively 2 g/L, 1.5 g/L, 0. 015 mmol/L and 0. 05 mmol/L; （ 3 ） the highest activities of laccase produced from G. candidum M3 under optimal conditions in a 5-L mechanically-stirred fermentor and a 7-L air-lift fermentor reach 23.8 and 36. 9μmol/（s· L）, respectively; （4） the air-lift fermentor is more suitable for the laccase production from G. candidum M3 ; and （5） after a treatment with the produced crude laccase for 1.5 h, the decoloration rate of azo dyes reaches 90. 2%. The decoloration ability of the produced laccase for azo dyes is also proved by Vis-UV spectrum.

    Improvement of Fermentation Medium for High-Efficiency Nitrobacteria by Sequential Experimental Design
    Ren Jie Lin Wei-tie Luo Xiao-chun Xie Ming-quan
    2008, 36(12):  91-96. 
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    In order to produce commercial nitrobacteria for the removal of nitrites in aquaculture water, the sequential experimental design including the Plackett-Burman design, the factorial design, the steepest ascent method and the central composite design was used to optimize the fermentation medium of nitrobacteria isolated from a shrimp pond. The optimal composition of the medium was determined as 1.86 g/L NaHCO3, 2.04 g/L NaNO2, 0. 2 g/L Na2CO3, 0. 2g/L NaCl, 0. 1 g/L KH2PO4, 0. 1 g/L MgSO4.7H2O , and 0. 01 g/L FeSO4.7H2O. The results indicate that, by using the nitrobacteria cultured with the optimal medium, the nitrite oxidation rate increases from 580. 7mg/（g · d） to 859.5 mg/（ g · d）, and the nitrites in both the simulated and the field aquaculture systems can effectively be oxidized.

    Improvement of Lipid Content of Chlorella pyrenoidosa Two-Step Cultivation
    Huang Guan-hua Chen Feng Wei Dong
    2008, 36(12):  97-101. 
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    Based on the growth rules of Chlorella pyrenoidosa （ C. pyrenoidosa） and the characteristics of intracellular lipid accumulation in nitrogen-deficient condition, the improvement of lipid content of C. pyrenoidosa using a two-step cultivation method was investigated. The results show that （ 1 ） the optimal mass concentrations of glucose and KNO3 for the high-density cultivation of C. pyrenoidosa are respectively 20 and 1. 50 g/L; （2） with 1.50 g/L KNO3 as the nitrogen source, the biomass of C. pyrenoidosa increases from （7.55 ± 0. 23 ） g/L in the single-step cultivation to （9. 23 ±0. 11 ） g/L in the two-step cultivation; （3） the contents of intracellular lipid and total fatty acids in the two-step cultivation .respectively increase by 5.8% and 5.2% ; and （4） the calorific values improves from （23.58 ±0. 02） kJ/g to （25.52±0.03） kJ/g. It is thus concluded that the two-step cultivation not only results in a high-densitv cultivation of C. pyrenoidosa but also effectively increases the cellular linid content.

    Stability of B-Phycoerythrin/Gel Complex
    Hu Jin-mei Chen Feng Guo Si-yuan
    2008, 36(12):  102-105. 
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    The stabilities of B-phycoerythrin （B-PE）/sodium alginate and B-PE/gelatin complexes were inVestigated by means of the resonance light scattering （RLS）, the visible absorption spectroscopy and the differential scanning calorimetry （DSC）. The results show that the RLS intensities of the two complexes both increase with the concentrations of sodium alginate and gelatin, respectively, and that B-PE has a stronger interaction with gelatin than with sodium alginate because the light and thermal stability of B-PE/sodium alginate is higher than that of B-PE but lower than that of B-PE/gelatin.

    Purification and Hydrolysis Characteristics of Alkaline Protease from Actinomucor elegans AS3. 2778
    Pan Jin-quan Luo Xiao-chun Xie Ming-quan
    2008, 36(12):  106-111. 
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    The proteases from mucor is of relatively high hydrolysis efficiency to soy protein and of good debittering effect to the hydrolysates of protein. In order to effectively explore such proteases, one protease was purified from the fermented wheat bran by Actinomucor elegans AS3. 2778 using ion exchange chromatography, hydrophobic chromatography, and gel chromatography, and its hydrolysis properties to soybean protein were investigated. The results show that the purified protease is a single-chain polypeptide with a relative molecular mass of 32000, which has relatively higher hydrolysis activity to soy protein at 55 ℃ and pH8.0 - 10. 0 than such commercial proteases as papain, Alcalase and Protamex. It is thus concluded that, as compared with the above-mentioned commercial proteases, the purified protease is of more extensive peptide-bond selectivity, stronger affinity to soybean protein isolate （SPI）, and more cleavage points on SPI.

    Cloning and Expression of β-1,4-Endoglucanase Gene
    Guo Cheng-shuan Cui Tang-bing Guo Yong
    2008, 36(12):  112-115,145. 
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    β-1,4-endoglucanase encoding gene was cloned from Bacillus pumilus H9 producing alkaline cellulase, with its sequence and domain being also analyzed. Then, the gene was cloned into Escherichia coli （E. coli） prokaryotic expression vector pET20b, and the construct pET20b-EglA was transformed to a E. coli BL21 （DE3） strain. Finally, by using the SDS-PAGE electrophoresis, the expressed product was detected. Experimental results show that （ 1 ） the β-1,4-endoglucanase gene sequence, 1980 bp in size with 659 amino acids being coded, is effectively expressed in E. coli; （2） the β-1,4-endoglucanase with a relative molecular mass of about 73 000 consists of two discontinuous domains： one is an N-terminal catalytic domain belonging to the glycoside hydrolase family 9 and the other is a C-terminal cellulose-binding domain belonging to the carbohydrate 3; and （3） the activity and stability of the recombinant β-1,4-endoglucanase at different temperatures and pH values are both close to those of the original strain.

    Gene Expression and Structure-Activity Relationship of Melittin Analogues
    Zhao Ya-hua Bai Bao-yi Liu Ai-shan Gao Xiang-yang LinJian-rong
    2008, 36(12):  116-121. 
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    By using the previously-established model of quantitative structure-activity relationships （QSAR） for melittin, six genes of melittin analogues were predicted and designed. Then, by adopting the Pichia pastoris expression system, the recombinant plasmid of pPICZα-A-Mel was constructed and transformed into yeast by electric shock for the secretory expression in Pichia pastoris GS115, with α-factor as the secretory signal. The expression products were purified via 6 × His affinity chromatography after screening and inducing, and were then confirmed by Tricine-SDS-PAGE. The results show that （ 1 ） four of the expression products of the six newly-designed genes reveal stronger antibacterial activity than the recombinant natural melittin, while two of them are of weaker activity; （2） the inhibition titer of Analogue [ C ] with the strongest antibacterial activity is i. 62 times that of the recombinant natural melittin ; （3） the inhibitory activity of Analogue [ B ] with the highest expression level is next to that of [ C] ; and （4） the hemolytic activities of the six analogues are all less than 1/15 as compared with that of the recombinant natural melittin. It is thus concluded that the optimized design of melittin molecular is reasonable and feasible in maintaining or improving the antibacterial activity and in reducing the hemolytic activity.

    Bioinformatic Analysis of Xylose Reductase for Site-Directed Mutagenesis
    Du Hong-li Wang Jing-fang Zeng Qi-kai Ling Fei Wei Dong-qing Lin Ying Wang Xtao-ning
    2008, 36(12):  122-127. 
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    One of the key problems affecting the ethanol production from cellulose is the unbalanced redox between xylose reductase （XR） and xylitol dehydrogenase （XDH） in the xylose metabolic process. In this paper, some key amino acids that affect the activity or coenzyme specificity of XR are identified based on the database sources by using the bioinformatic methods such as the homology modeling and the molecular docking. The results indicate that （1） amino acids Lys21, Va1222, Glu223, Phe236 and Thr273 in Pichia stipitis XR have hydrogen bonding with nicotinamide adenine dinucleotide phosphate （NADP）, while amino acids Va1222, Glu223, Phe236, Glu237 and Thr273 have hydrogen bonding with nicotinamide adenine dinucleotide （NAD） ; （2） the mutagenesis of Lys21 （conserved） is likely to result in the binding of Pichia stipitis XR with NAD only, while that of Glu237 （ not conserved） is likely to result in the binding with NADP only; （3） unconserved amino acids Asn278 and Arg282 in Candida tropicalis XR have hydrogen bonding with NADP; and （4） the mutagenesis of Ash278 or/and Arg282 is likely to result in the unbinding of Candida tropicalis XR from NADP.

    Application of ISSR Marker and ITS Sequence to Investigation of Genetic Variation of Aquilaria sinensis
    Shen Yan-jing Yan Ping Zhao Xuan Pang Qi-hua Zhao Shu-jin
    2008, 36(12):  128-132. 
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    This paper deals with the genetic variation, genetic relationship and molecular identification of different populations of Aquilaria sinensis （A. sinensis） by employing the inter-simple sequence repeat （ISSR） marker and the internal transcribed spacer （ITS） sequence of ribosomal RNA （rDNA）. The results of ISSR marker show that 60. 0% of the 80 bands amplified with 7 ISSR primers are polymorphic bands, and that the genetic distance among the 9 populations of A. sinensis varies from 0. 073 3 to 0. 4213. The results of rDNA ITS sequence show that there are only 6 variable sites in the 9 populations, with a genetic distance varying from 0. 0000 to 0. 0110. Moreover, as the cluster graphs respectively obtained from the ISSR marker and the ITS sequence, different in shape but similar in trend, well describe A. sinensis and its related species in different populations, both the ISSR marker and the ITS sequence are effective in revealing the genetic variation and genetic relationship of A. sinensis.

    Preparation and Identification of Specific Monoclonal Antibody Against Cadmium Chelate
    Liu Gong-liang Wang Ju-fang Li Zhi-yong Liang Shi-zhong
    2008, 36(12):  133-137. 
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    In order to obtain the specific monoclonal antibody against cadmium chelate, 1-（4-isothiocyanobenzyl） ethylenediamine-N, N, N′, N′-tetraacetic acid （ITCBE） was used as the bifunctional chelator to prepare the hapten. The product was then coupled with keyhole limpet hemocyanin Cd-ITCBE-KLH or bovine serum albumin （BSA） to produce immunogen and coating antigen. After an identification of the antigen and the immunization of Balb/c mice, the hybridomas were screened via the fusion of spleen cells and SP2/0 myeloma cells, and positive clones against Cd-ITCBE-BSA were selected by subcloning. Finally, mAb 3A9D9G7 was obtained from the ascites. ELISA results indicate that mAb 3A9D9G7 with a κ-type light chain, whose ascites titer and apparent affinity constant are respectively 4 × 10 -4 and 1.44 × 1010 mol/L, belongs to IgM subclass. It is of a sensitivity of lower than 50μg/L and a cross-reactivity rate of less than 0. 90%. Thus, mAb 3A9D9G7 is highly specific against cadmium chelate and is suitable for the rapid detection of cadmium residue in environment and food samoles.

    Mathematics
    Analysis of Fluctuation of Hong Kong Hang Seng Index
    Fang Wei-dong Li Kun Zhang Jian-gong
    2008, 36(12):  138-141. 
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    In this paper, a complex network model describing the relationship between the Hang Seng Index and the trading volume of Hong Kong stock market is established by means of the coarse graining method, and its topology and statistical characteristics are analyzed, thus revealing the fluctuation of the Hang Seng Index related to the trading volume. Then, by calculating the betweenness centrality and inverse participation ratio of each network node, some important topology nodes are obtained. These nodes denote significant patterns that play important roles in the information control and transportation of the stock market, and help to understand the fluctuation regularity of the stock index related to the trading volume. Finally, by comparing the proposed network model with the existing random networks, it is found that the fluctuation of the Hong Kong Hang Seng Index related to the trading volume is statistically stable.

    Existence of Solutions to a Class of Biharmonic Equation with Hardy Potential
    Wang You-jun Shen Yao-tian
    2008, 36(12):  142-145. 
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    In this paper, a new Sobolev space is established and a compact embedding theorem is given. Then, the eigenvalue problem of the biharmonic equation with critical exponents is analyzed. Finally, by using the Mountain Pass Lemma satisfying the Cerami condition, the existence of the nontrivial solutions to a class of biharmonic equation with Hardy potential and critical parameter is discussed in the established Sobolev space.

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