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Table of Content

    25 September 2006, Volume 34 Issue 9
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    Materials Science & Technology
    Natural Rubber/Montmorillonite Nanocomposites Prepared by Mixing Intercalation Method
    Ouyang xing Luo Yuan-fang Jia De-min
    2006, 34(9):  80-85. 
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    NR/HMT (Natural Rubber/Organo-Montmorillonite)nanocomposites were prepared with an organic modified montmorillonite and a novel reinforcing accelerator by means of mixing intercalation method.The structu and morphology of the prepared nanocomposites were then characterized by XRD and TEM,and the interaction be-tween montmorillonite and rubber was investigated by the apparent crosslinking density determination and the infra-red spectral analysis.Moreover,the intercalation process of rubber chains into the montmorillonite interlayers in the mixing and curing processes was researched by XRD.The results show that montmorillonite can disperse in the rub-ber matrix in a nanoscale,that the reinforcing accelerator can enhance the interaction between montmorillonite and rubber,that the intercalation of the macromolecular chains of natural rubber into the interlayers of montmorillonite begins in the mixing process and mostly completes in the induced period of vulcanization before the scorch time point,that the dispersion of montmorillonite in a nanoscale is further improved in the curing period till to a complete vulcanization.and that the mechanical and dynamic mechanical properties of NR/HMT nanocomposites with 2%~10% of mass ration of HMT to NR are superior to those of the vulcanizate with 40% of mass ration of N770 carbon black to NR.

    Die-Swell Behavior of PP/HGB Composite Melt
    Liang Ji-zhao Zhong Ming-qiang
    2006, 34(9):  86-89. 
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    The die-swell behavior of the PP(polypropylene)filled with HGB(Hollow Glass Bead),namely of the PP/HGB composite．was investigated using a XNR-400A melt flow indexer at 1 90 to 230 ℃ with the load of 1.0 to 8.0 kg.The results show that the die-swell ratio B of the melt linearly increases with the shear stress at 200 ℃,that the die-swell ratio presents a approximately linear decrease with the increase in temperature at a load of 3.80 kg,that the die-swell ratio nonlinearly decreases with the increase in the volume fraction( Φf)of HGB at 1 90 ℃,and that,when Φf=1 0% and P=3.80 kg,the die-swell ratio increases with the HGB diameter.

    Bisphenol-A Epoxy Resin Toughened and Reinforced by Hyperbranched Epoxy Resin
    2006, 34(9):  90-94,116. 
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    Liquid low-viscosity hyperbranched epoxy resin HTDE-2 synthesized by one-Dot method was used to toughen and reinforce the bisphenol-A epoxy resin, and the effect of HTDE-2 content on the mechanical and ther-mal performances of the HTDE-2/bisphenol-A hybrid resin was investigated.Then,the structure of HTDE-2.the perform ance as well as the toughening and reinforcing mechanism of the HTDE-2/bisphenol-A hybrid resin were researched by means of FTr-IR,SEM,DSC,TGA,DMA and molecular simulation technologY. The resuhs indicate that the mechanical perform ance of the hybrid resin first increases with the HTDE-2 content to a maximum. and then decreases,and that,at a HTDE-2 mass fraction of about 9% in HTDE-2/bisphenol-A hybrid resin. the hybrid resin is of excellent integrated perform ance,because its tensile strength, flexural strength,impact strength and frac-ture toughness respectively increase by 20.7% ,14.2%, 208.8% and 74.9% .However.the corresponding glass transition temperature and therm al degradation temperature are found decreasing to some degree.

    Preparation of Zirconia-Doped Titania Nanopowders by Co-Precipitation Method and Corresp0nding Phase Transformation
    Lu Ming Rao Ping-gen Wu Jian-qing
    2006, 34(9):  95-98. 
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    In order to reveal the promotion or restraint of phase transformation caused by the doping of ions,nano-sized TiO2 doped with Zr4+ was prepared by means of co-precipitation method,respectively with the Zr mole frae-tions of 0,2% ,5% ,7% ,10% and 13% .The influence of Zr4+ doping on the phase transform ation of TiO2, fronano-sized anatase to rutile was then investigated. TEM results indicate that the prepared TiO2 anatase is 1 0 to 20 nm in diameter．XRD results show that the Zr4+ doping restrains the growth of anatase ertstallites,improves the start temperature of phase transform ation from 750℃ to 850℃ ．Moreover，in order to avoid the form ation of ZrTiO4 from the reaction of Zr and TiO2,the mole fraction of doped Zr4+should be less than 10% .

    Preparation and Catalytic Performance of La0.8Sr0.2CoO3Supported on M ullite Fiber Ceramic
    Zeng Ling-ke Duan Bi-lin Liu Ping-an Wang Hui Shui An-ze Liu Yan-chun Wang Xiao-hua
    2006, 34(9):  99-103. 
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    The perovskite-type La0.8Sr0.2CoO3supported on the mullite fiber porous ceramic was prepared by means of impregnation method,and was then characterized by SEM and XRD,thus coming to the( onclusion that the perovskite-type composite oxidant can disperse on the surface of mullite fiber ceramic. The catalytic activity of La0.8Sr0.2CoO3for NO and CO was also evaluated. The effect of the doped PdCl2,with a mass fraction of 0.1% on the catalytic activity of the perovskite-type La0.8Sr0.2CoO3 was finally discussed.The results show that the conver-sion rates of NO and CO respectively reach 74.5% and 99% at 601 ℃ without Pd doping.and both reach 100%at 350 ℃ with little Pd doping.

    Numerical Simulation of Melting Process in Single·Screw Extruder Under Vibration Force Field
    Feng Yan-hong Qu Jin-ping Liu Bin He He-zhi Jin Gong Zou Xin-liang
    2006, 34(9):  104-110. 
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    In order to investigate the effect of vibration force field on the melting process in a single-screw extruder,a simplified 2 D dynamic melting model is established by adopting the assumption of”flowing solid”and the theory of hydrokinetics to solve the problem in the whole melting region.Thus,the problems of phase change and the so-lid-melt interface track are successfully solved. Moreover,as the melting process is of a non-isothermal phase change and the polymer presents time-dependent nonlinear viscoelastic characteristics in vibration force field, a self-amended non-isothermal Maxwell viscoelastic constitutive model that reflects the relaxation time spectrum of the polymer is developed.The dynamic melting process is finally simulated,followed by the analysis of the effects of vi-bration frequency and amplitude on the melting process.

    Electronics, Communication & Automation Technology
    Intelligent Bang-Bang Predictive Control Algorithm Based on Bang-Bang Control
    Cao Jian-zhong Luo Fei Xu Yu-ge Huang Jin-qi
    2006, 34(9):  1-7. 
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    In order to solve the complex problems of adding the additional constraints of state variables,getting the Bang-Bang curve and determining the optimal path in the application of the Bang-Bang control theory,an intelligent Bang-Bang predictive control method is proposed.In this method,a new set of control signals is first presented ac-cording to the discrete convolution principle.Next,a new switching equation and a new deceleration law are con.structed.Then,the deadbeat addition control restricted by threshold signals is accomplished with the flame of Bang-Bang control.The proposed method improves the strategy and algorithm of the predictive control,guarantees the dynamic performance of the control system,makes the transition time reduce to a value less than that in ideal Bang-Bang control,and enables the predictive control system to attenuate monotonously without static errors.Moreover,it is of the advantageous of quick reaction,high precision,good robustness to the output turbulence and wide scope of application.Its effectiveness is finally verified by simulated results.

    Analysis of Energy-Consumption Performance for Wireless LANs
    Li Ning Shi Cheng-guang Xie Sheng-li
    2006, 34(9):  8-12. 
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    In order to reveal the energy-consumption performance of IEEE 802.1 1 DCF(Distributed Coordination Function)in a saturated wireless LAN environment,both the average energy consumption and the average system time of the node in each virtual slot are calculated according to the corresponding transmission probability and con-ditional collision probability of the node.The power consumption of the node and the goodput energy-consumption rate of the network are thus obtained.Analytical results show that,(1)the longer the packet and the higher the channel rate,the lower the goodput energy -consumption rate which means a better energy-consumption perfor-mance;(2)there exists a near-linear relationship between the goodput energy-consumption rate and the network size;(3)the basic access mechanism becomes better than the RTS/CTS access mechanism at an increasing chan-nel rate;and(4)the average power consumption of the node is mainly determined by the received power consump-tion when the network size is large enough,but rarely affected by the transmitted and idle power consumptions.

    Tolerance Analysis of Circuitry Realization of Chua’s Chaotic Circuit
    Luo Rong-fang Lin Tu-sheng
    2006, 34(9):  13-17,30. 
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    First,the dynamic characteristics of the circuit system under the influence of various circuit parameters are analyzed on the basis of the periodic orbit theory about the chaotic attractor and by means of the circuit simula-tion technology,and the chaotic region diagram in the circuit parameter plane is presented.Next,the standard values of circuit parameters and the maximum possible parametric range when the circuit has 2-scroll attractors are calculated according to the presented chaotic region diagram.Finally,the steps of the algorithm in selecting the pa’rameters of the Chuag circuit are proposed.All these provide theoretical guidance for the realization of the chaotic oscillatory circuit.

    Algorithm of Multi-Channel Echo Cancellation by Means of Nonlinear Pre-processing
    Wang Jie Xie Sheng-li
    2006, 34(9):  18-21. 
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    In the multi-channel echo cancellation.the nonlinear pre-processing is always used to overcome the nonconvergence of the filter caused by the strong correlation of input signals.How to choose a suitable nonlinear transformation coefficient is important to the assurance of acoustic quality and the cancellation of signal corelation. In order to solve this problem,this paper proposes a fuzzy logic-based method with little calculation increment to adjust the nonlinear transformation coeficient(α)that reasonably changes with the corelation of input signals,by which the communication quality can be effectively assured and the convergence of the filter can be greatly accelerated.The feasibility and superiority of the proposed method is verified by simulated results.

    Gradient-Based Structural Similarity for Image Quality Assessmen
    Yang Chun-ling Kuang Kai-zhi Chen Guan-hao Xie Sheng-li
    2006, 34(9):  22-25. 
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    Although the SSIM (Structural Similarity)model,an assessment model of image quality based on the structural information,has been proved to be better than the PSNR(Peak Signal to Noise Ratio)or the MSE(Mean Square Error)model,there still remain some deficiencies in assessing badly blured images.In order to solve this prob-lem,this paper proposes a gradient-based structural similarity(GSSIM)model that takes the gradient as the main strut-tural information of an image.Experimental results show that the proposed GSSIM model is more consistent with human visual system and can assess the quality of blured images more precisely than the SSIM and PSNR (MSE)models.

    Self-Deployment Algorithm for Mobile Sensor Networks in Unknown Environm ent
    Song Guang-ming Zhuang Wei Wei Zhi-gang Song Ai-guo
    2006, 34(9):  26-30. 
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    In order to implement the self-deployment of wireless sensor networks with controllable mobility,a selfdeployment algorithm for mobile sensor networks in unknown environment is proposed.In this algorithm,the meth-ods 0f the artificial potential field and the certainty grid are adopted and the certainty is used to abstractively repre-sent the obstacles.Moreover,the network is forced by the virtual repulsive forces of the cells in the active windows to sDread itself throughout the environment. Simulated results show that the proposed algorithm is effective in the self-deDloyment 0f m0bile sensor networks,with a greatly increased coverage at the end of the deployment.

    Solving of Conveyor Stoppage of Mixed-Model Assembly Line Based on Ant Colony Algorithm
    Ye Ming Wang Ning-sheng
    2006, 34(9):  31-34,39. 
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    The concept of extendable region is introduced to solve the conveyor stoppage problem on a mixed-model assembly line,and some problems,such as the necessary and suficient conditions due to which the conveyor stoppage may occur,and the bounds of the objective function are studied.Then,a restricted-ACO (Ant Colony Optimization)algorithm is proposed to solve the car-sequencing problem with buffer restriction under a round painted body storage,which reaches the objective to minimize the total conveyor stoppage time.Illustrations are finally presented to reveal the advantages of the proposed strategy and the effect of the leveling of material flow on the conveyor stoppage.

    Design of Terminal Surveillance System of Power Transformer Based on GPR S
    Xu Yue-hua
    2006, 34(9):  35-39. 
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    In order to collect,analyze and deal with the variable parameters of power transformers.a terminal sur-veillance system is designed with the applications of the high-precision parameter collection module,the high-per-formance microprocessor and the SIMENS wireless communication module.By the proposed system,variable func-tions of the power transformer,such as the inquiring of current states and historical curves(data),the long-dis-tance surveillance and the alarm,can be easily accomplished.The application results indicate that the proposed surveillance system is suitable for intelligentized and networked power transform ers,for it possesses complete func-tions,good stability and single electric circuit.

    Robust AQM Congestion Control Algorithm Based on Gain Adaptive Smith Predictor
    Xiang Shao-hua Xu Bu-gong Peng Da-zhou Wu Sai
    2006, 34(9):  40-44. 
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    A robust AQM (Active Queue Management)congestion control algorithm (GAS-PI)is proposed on the basis of the gain adaptive Smith predictor and according to the Lyapunov asymptotic stability theorem.This algo-rithm is of simple structure,good robustness and excellent network control performance.Moreover,it overcomes the negative impact on the queue stability caused by the large delay.Simulated results indicate that,by the proposed GAS-PI algorithm ,the overshoot of queue can be effectively decreased,and a higher responsive speed as well as a steadier queue can be obtained,that is,the buffer queue quickly converges to the equilibrium point when the net-work is of HTTP disturbance and great overload change.and the dynamic perform ance of large-delay networks remains in good condition.

    Environment Science & Technology
    Screening of Plants in Constructed W etland with Low-Concentration Domestic Wastewater in South China
    Hu Yong-you Wang Xin Zhang Tai-ping Guo Qing-wei Hu Chun-ming Zheng Bing-hui
    2006, 34(9):  111-116. 
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    In order to widen the application of constructed wetland, the experiments to screen 1 4 species of candi-date plants were caried out in pots with low-concentration domestic wastewater. Experimental results indicate that.as compared with the control without plant，most units with plants have no significant improvement in the caDabilitv of COD removal,but have significant improvement in the capability of nitrogen and phosphorus removals. Further-more,when the hydraulic retention time is 8 and 24 h0urs, the average contributions of the plant uptake to nitr0gen removal respectively reach 44.5% and 40.0%, and those for phosphorus removal respectively reach 20.9% and 25.1% .All these indicate that,instead of the capability of COD removal, the capability of nitrogen and phospho-rus removals can be used as a criterion for screening plants suitable to constructed wetland. also with the fact0rs such as the endurance of hard environment and the ornamental effect of the plant being considered.

    Alternative Aerobic and Anaerobic Composting of Municipal Sewage Sludge M ixed with Organic Garbage
    Zhou Shao-qi Lu Wei-dong Lin Yun-qin
    2006, 34(9):  117-120,132. 
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    This paper aims at the variation laws of the phvsic0chemical and bio-toxic characteristics of municipal sewage sludge and organic garbage during the alternative aerobic and anaerobic composting.In the investigation,municipal sewage sludge,municipal organic garbage and bulking agents were uniformly mixed in a mass ratio of 3:3:1 to carry out a eomposting for 60 days.The results show that the contents of the total organic carbon.the vola-tile solids and the total nitrogen decrease respectively from 59.62% to 40.2 1% .from 76.47% to 69.85% and from 0.94% to 0.68% ,while the content of the total phosphors increases from 0.59% to 0.86% ,and that the content of humus substances remains at about 7% and the germ ination ratio reaches 72.5% at the end of the eom-posting.All these mean that the composting materials become mature compost with an greatly improved bioaetivitv .

    Stability and Its Fuzzy Assessment of ANAMMOX Reactor
    Jin Ren-cun Zheng Ping Hu Bao-lan Chen Xu-liang
    2006, 34(9):  121-127. 
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    The performance stabilities of different ANAMMOX (Anaerobic Ammonium Oxidation) reactors were quantitatively compared and investigated by means of statistic and fuZZV mathematical methods. The resuIts show that,for the reactors with the same confguration,the tolerance to the shock load is greatly affected bv the load type,that the stability parameters of the reactor under the subsh-ate shock load are 1.68 to 5.44 (2.9 in average 1 times those of the reactor under the hydraulic shock load, that the ANAMMOX reactors are m0re tolerant to the hydraulic shock load than to the substrate shock load, that the reactors with different configurations displav different performance stabilities under the same load ,and that the granular sludge bed stands the first in the stabilitv under the substrate shock load, followed by the biofilm reactor and the SBR (Sequencing Batch Reactor).However,SBR takes the first place under the hydraulic shock load,followed by the granular sludge bed and the biofilm reactor.Moreover,the results of fuzzy assessment indicate that the granular sludge bed is most stable t0 the shock load.while SBR is the most unstable of the three reactors.

    Chlorophenol Degradation and M icroorganism Community Structure of Immobilized Granular Sludge Under Micro-Aeration Condition
    Chen Yuan-cai Chen Zhu Lan Hui-xia Fu Shi-yu Guo Jing
    2006, 34(9):  128-132. 
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    A comparison of PCP(Pentachl0r0phen01)degradation was made in micro-aeration and anaerobic condi-tions with three series of batch experiments;(1)anaerobic granular sludge and the mixed isolated aerobic bacteria were eo-immobilized with PVA(Polyvinyl Alcohol)and sodium alginate by means of freeze;2)isolated aerobic bacteria were first immobilized with PVA and sodium alginate and then mixed with anaerobic granular sludge;and (3)isolated aerobic bacteria were directly added in anaerobic granular sludge.The results indicate that,in the mi-ero-aeration condition.the co-immobilization of anaerobic granular sludge and isolated aerobic bacteria can enhance the PCP degradation through the synergism of aerobes and anaerobes.Whereas in the anaerobic condition.there is no significant difference in degradation rate among the three immobilized anaerobic granular sludge.Moreover,the presence of the activities of aerobes and anaerobes in the immobilized sludge is further conformed by specific activi-ty experiments in aerobic and anaerobic conditions,and the microorganism community structure of the eo-immobi-lized granular sludge in micro-aeration condition is also deduced.

    Computer Science & Technology
    Approach to Extracting Crosscutting Concerns in Software Systems Based on Concept Analysis
    Su Yang Kang Li Hu Sheng-ming Chen Ping
    2006, 34(9):  45-49,55. 
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    The framework of aspect-oriented software reverse engineering is proposed to solve the comprehension and evolution problems of crosscutting attributes in the software legacy system. An approach to the formal concept analysis driven by use case is then presented based on the proposed framework.with the aim of c0nverselv recovering the crosscutting attributes on the level of requirement models.With this approach.the execution profiles of the objective system are analyzed using concept lattices.thus enabling the identification and extraction of the invoked sets of the crosscutting system use case models.Finally. the crosscutting methods are abstracted into the earlv aspects of a software system.As compared with the aspect-mining techniques. which are mainly applied to the code reconstruction on the program code level,the presented approach is more suitable for the program comprehension on a higher abstract level. Moreover,as a kind of semiautomatic approach with the strategy of incremental resuIt extraction,the proposed approach is more controllable and adaptive when the requirements in the reverse engineering are changed.

    Attribute Reduction Using Attribute Variable Partition of Rough Set
    Deng Jiu-ying Mao Zong-yuan Xu Ning
    2006, 34(9):  50-55. 
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    By means of the methodology of rough set,different attribute classification methods for decision systems are first analyzed in this paper,and the attribute significance as well as the extremely small subset of the attribute relative reduction caused by a classification variety is discussed.Next, the intrinsic factor to affect the interaction between the attribute classification method and the attribute reduction results is revealed. Then.a scheme for performing effective attribute classification and a strategy for determining reasonable attribute reduction subsets are in-troduced,and an algorithm is presented to implement the corresponding software according to the strategy . By using the presented algorithm,a relative reduction subset is finally selected. Experimental results verify the effectiveness of the proposed strategy and algorithm.

    Traffic & Transportation Engineering
    Pavement Performances of Dam Embankm ent Roads Strengthened by Ionic Soil Stabilizer
    Wang Yi-min Zhang Li-juan Chen Ye-kai Guo Bai-lin Tonh Ming Liu Wei
    2006, 34(9):  56-61. 
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    The tests of pavements of dam embankment roads strengthened by ISS(Ionic Soil Stabilizer,located in the ditch of Zhiman reservoir in Zhanjiang,Guangdong,were carried out,and the coresponding pavement perform-ances of the roads were investigated.In laboratory,the compaction feature,intensity feature and anti-water stability of the ISS-strengthened soil were tested,thus coming to the conclusions that the mixture proportion is mainly deter-mined by the strength and anti-water stability of the mixture and that the optimum mixture proportion in site for the sandy silt with high liquid limit is 0.3L of ISS per cube meter soil and 6% limestone of the dry soil in mass.More-over,by the experiments in the field,the construction procedure and techniques for the ISS-strengthened soil pave-ment were summed up,and the construction procedure,stabilizing effect and economical benefit of the mixing in plant and the mixing in place were then compared and analyzed.The results indicate that Ihe ISS-strengthened soil pavement has the advantages of good beating capability,evenness,durability,anti-water stability,simplicity,fa-cility,low cost and obtaining raw materials on the spot.

    Experimental Analysis of Rut Prediction M odel for Asphalt Pavem ent with Flexible Base
    Chen Shao-xing Zhang Xiao-ning Xu Quan-liang Meng Shu-tao
    2006, 34(9):  62-65. 
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    First,a rut prediction model,in which the moduli of different layers were inversely calculated by the FWD (Falling Weight Deflectometer)deflection basin,was introduced.Next,the deflection and stress on each surface of the layer as well as the permanent deform ation parameters of each layer were calculated using the Kenlay.er program.Then,the ruts with different loading repetition numbers were predicted.Finally,a full-scale accelerated loading test was carried out to analyze the rut prediction model and the rut form ation law.The results indicate that the prediction model accords well with the form ation and size of the practical rut.

    Estimation Algorithm with Kalman Filtering for Road Travel Time Based on Grey Relation Analysis
    Wen Hui-ying Xu Jian-min Fu Hui
    2006, 34(9):  66-69,75. 
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    In order to improve the self-adaptability of Kalman filtering applied to the estimati0n of time series. a real-time estimation algorithm for road travel time is put forwarded based on the grey relation analysis. The grev re-lation analysis of various factors to affect the travel time series is first caried out based on the gray the0ry. and the main factors to influence the road travel time are picked out according to the grey relevancy degree. Then.the cor-responding dynamic equations are set up,and the estimated values are obtained using a set of recursion form ulas.The real data of the road travel time collected in an artery in Shenzhen City are finallv used to perform simulated experiments.The results indicate that the proposed algorithm is suitable for the estimation of road travel time in natu-ral traffic flow because it is of better integrated perform ance than the conventional Kalman fihering model.

    Parameter Detection for Trafi c Flow Based on Characteristics of Video Corner Information
    Qin Zhong Xu Jian-min Liu Li-pin Shi Sheng-li
    2006, 34(9):  70-75. 
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    This paper proposes a detection method of traffic parameters based on the characteristics of video comer information,in which a detection region is divided into an initial one and a tracing one.In the initiative detection region,the existence of moving vehicles is tested,and a suppositional line state detection is carried out to deter-mine whether the vehicle is moving in,thus speeding up the calculation.W hen a vehicle is moving in, its com ers are firstly located and its state parameters are initialized.In the tracing region,the objections are segmented and traced on the basis of their comer characteristics and according to the kinetic consistency hypothesis of the rigid body.At the end of the tracing,the inform ation,such as the traffic flow,the average velocity and the vehicle type,is computed.

    Efect of Location of Temporary Pier in Incremental Launching Construction on M anufacture Error of Girder
    Wang Wei-feng Lin Jun-feng Ma Wen-tian
    2006, 34(9):  76-79,89. 
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    According to the characteristics of the incremental launching construction for continuous girder bridges and the variation of the internal force during the construction,a simplified structural calculation model was estab-lished by means of the displacement method.The proposed model was then used to analyze the efect of the location of temporary pier on the manufacture error of the girder and to reveal the relationship between the location and the corners at the ends of the incremental segments during the incremental launching construction of the continuous girder bridge.Consequently,the optimum position of the temporary pier propitious to the reduction of manufacture error was obtained.The proposed model was finally applied to the project of Zhujiang Western Bridge,the results verifying the correctness of the optimization results.

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