Journal of South China University of Technology(Natural Science Edition)

Design of Variable Structure Controller for Distributed Parameter Systems with Delays#br#

Cui Bao-tong　 Deng Fei-qi　 Wang Wei　 Liu Yong-qing

2003, 31(5): 1-5.

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The variable structure control problems for a class of parabolic distributed parameter systems with several delays are investigated．The sliding mode equation is established by using a nonsingular linear transformation and the non-memory and the variable structure controller of the system is designed．Furthermorethe regions of time reaching to sliding mode for motion trajectories are estimated．

Robust Reliable Exponential Decay H ∞ Stabilization for Linear Uncertain Systems with Multiple Time-delay

Peng Da-zhou　 Xu Bu-gong

2003, 31(5): 6-10.

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The paper is concerned with the reliable exponential decay stabilization for linear uncertainty systems with multiple unknown delays．The required exponential decay rate for such systems can be meet by the obtained controller． The results show that is in delay-dependent exponential kind and presented in the form of LMI problem so that it is easy to be calculated．A computation example is given to illustrate the proposed method．

Synthesis and Liquid Crystal Properties of Oligothiophene Derivatives

Liu Ping Hu Jian-hua Zhao Q- i zhong Zhou Xiao-ping Tong Zhen Xu Yun-hua Deng Wen-ji

2003, 31(5): 11-15.

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With the aim of developing new oligothiophene-based liquid crystals involving hydrogen bondingnew terthio-phene derivatives containing an alkylamide groupNN’-dialky- l55”-dibromo-22’：5’2”-terthiophene-44”-dica-rboxamide （DNC n DBr3Tn＝581618）were designed and synthesizedand their thermal behavior were examined．While DNC n DBr3T compounds with n＝81618were found to form smectic A phase．It is shown that the alkyl chain length greatly affects liquid crystal phase formation．The absence of liquid crystallinity in the corresponding ester derivatives suggests that intermolecular hydrogen bonding also plays a role in the formation of liquid crystal phase in the DNC n DBr3T system．The electrical opticaal and gelation
properties of DNC n DBr3T（n ＝81618） were reported．

Fractional Ultrafiltration Separation of Soy Peptides

Yang Xiao-quan Zhang Xin-hui Chen Shan Chen Zhong　 Zhao Mou-ming

2003, 31(5): 16-20,24.

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The fractionation of soy peptides by ultrafiltration separation was studied． Soy peptides products（hydrolysis degree of14．5％） can be separated into four components （＞30000u、10000～30000u、5000～10000u and ＜5000u） in terms of its molecular weight using fractional ultrafiltration separation system．The molecular weight distribution of each group was determined by filtration chromatography．The result showed that fractional ultrafiltration separation can effectively separate soy peptides．The molecular weight distribution of soy peptides with hydrolysis degree of 14．5％ mainly was below 5000 u．The soy peptides with different
molecular weight have different functional propertiessuch as solubilityviscosityfoaming property and
emulsifying property．The membrane filtrated flux decreased but the efficiency and selectivity of membrane
increased as the content of soy peptides increased with total reflux operation．It provided a feasible way to purify
soy peptides by fractional ultrafiltration．

Effect of Different Doping Acids on the Structures and Conductivity of Polyaniline#br#

Yu Huang-zhong Chen Ming-guang Huang He

2003, 31(5): 21-24.

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In this studythree kinds of polymers including emeralidine baseHClPANICSAPANI were synthesized by chemical methods．Their structural texture of undoped and doped polyaniline are investigated by FTIR and UV-Vis spectra．The results show that different doping polyaniline possess various structure and conductivity．We also analyse the effect of polymers’structure variety on conductivityand explain these results reasonably．

Study on the VE Procedure and Its Improving Approaches

Zhang Ca- i jia Chen We- i xiang　 Sun Dong-chuan

2003, 31(5): 25-33.

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Based on the system methodology of “Wul- i Shil- i Renli （WSR）”and through mathematical modelsthe hardness trend of traditional value engineering （VE） has been examined as well as a new WSR analysis procedure on VE is proposed．Compared with the VE procedure given in Chinese National Standard GB 8223—87the new modified VE procedure has largely been extended from originally only concerning objective “function／cost” relation to the “function／cost” relation of Wuli phaseShili phase and Renli phase．This new procedure makes traditional VE adaptable to complex management system．

Traffic Simulation Program Based on Cellular Automata Model

Jin Wen-zhou Zhang Jie Mei Dong-fang

2003, 31(5): 34-38.

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Based on cellular automata model and micro simulation models of dynamic traffic flowby C＋＋the mathematical model of traffic flow is changed to the simulation model consisted of computer programs by use of structure methodthus the movement of vehicles on the link is simulated．Stop technique is implemented successfully in the dynamic traffic flow display on screen．At lastthe evaluation of the simulation model and the simulation process are carried out by calculating the real surveyed data．

Theoretic Analysis of Static Characteristics of Novel Soft-switching Submerged Arc Welding Inverter#br#

Li Yuan-bo Huang Sh- i she Wang Zhen-min Li Yang　 Lu Pe- i tao

2003, 31(5): 39-42.

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In this paper the static characteristics of a novel soft -switching submerged arc welding inverter is designedand the basic rules are researched between static characteristics of soft -switching submerged arc welding inverter and its structures as well as parameters by applying the theory of power electronics and autocontrol．Finallyexperimental verification of the results is given．

Numerical Simulation on Flow Behavior of Cooling Water in Oxygen Lance#br#

Ma Xiang-jun

2003, 31(5): 43-46.

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The flow behavior of cooling water in the oxygen lance of a steelmaking company was simulated based on K-εturbulence model．The porosity coefficient method was introduced to treat the curved boundary．The results show that the existing lance tip is not effectively cooled because there exists a dead zone which results from the unreasonable structure of the baffle．The structure of the baffle was optimized by numerical simulationand the optimized baffle can make cooling water cool the lance tip effectively with high velocity．

Batch Study on the Nitrification Process Characteristics Using Biological Porcelain Granule#br#

Luo Hua- i qing Hu Yong-you　 Chen Zhu

2003, 31(5): 47-50,55.

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Batch studies on the nitrification process using biological porcelain granule under different alkalinitytemperature and P／N ratio（in mass） were performed．The results show that increasing the alkalinity in certain range is favorable for ammonium oxidation and NO －2 -N accumulation．Moreoverthe appropriate mass ratio of NH ＋ 4 -N to NaH-CO 3 is1／12～1／16．Temperature has important influence on NO －2 -N accumulation．When temperature is below32℃NO －2 -N decreases markedly whereas NO － 3 -accumulates．The nitrosomonas and nitrobacteria will be inhibited and the rate of nitrification will decrease in38℃．The maximal accumulation of NO －2 -N could reach89．94％ of theNH ＋4 -N added at the beginning of the process in36℃this suggests that36℃ is the most favorable temperature for the accumulation of NO －2 -N．The nitrification process in three P／N ratiosi．e．01／10and1／5was studied．It shows that the average oxidation rate of ammoniumthe accumulation rat when P／N ratio increases．This implies that a negative correlativity is between them．Thusto make the nitrification process well performP／N ratio should be controlled under1／10．

Catalytic Oxidation of Wastewater Containing Phenol by Homogeneous and Heterogeneous Fenton-type Catalysts#br#

He Chun　 Xu Ke-feng　 Xi Hong-xia　 Li Zhong

2003, 31(5): 51-55.

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In this work the application of homogeneous and heterogeneous Fenton-type catalysts in catalytic oxidation of wastewater containing phenol is investigated．Orthogonal and single factor experiments in homogeneous phase are carried out in order to determine the optimum reaction conditions for oxidation and degradation of phenol in specific wastewater．On the basis of Fenton reaction mechanismthe catalytic oxidation mechanisms of Fe3＋in homogeneous and heterogeneous phases are discussed．Furthermorethe experiments for catalytic oxidation and degradation of phenol in wastewater on Fe 3＋／permutite and Fe3＋／activated carbon are performedand then comparison between the degradation reactions of phenol in homogeneous and heterogeneous reaction systems is made．Results show that the degradation efficiency of phenol in heterogeneous reaction system is obviously higher than that in homogeneous reaction system．The degradation efficiency of phenol is up to93．02％ when Fe3＋／activated carbon is used as catalyst．

Experimental Research on the Rare Earth Elements in the Soil from BichongGuangzhou under Imitated Acid－rain Leaching#br#

Shi Lin　 Yi Xiao－yun　 Zou Zhi－yi

2003, 31(5): 56-58.

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A leaching process is studied for REE solubility in soils from BichongGuangzhou acted by imitated acidrain．Experimental results show that the effect of imitated acid－rain on REE mobility and migration in the soil is enormous．The lower pH value and higer SO2－4content in imitated acid－rain isthe larger REE solubility amount the soil possesseswith the range from8．98％ to11．95％．The solubility amount of LREE is larger than that of HREE in soils．

Preparation and Nutritional Evaluation of Egg-tofu and Milk-tofu#br#

Xu X- i l Guo S- i yua Li Lin Gao Jian-hua　 Cai Miao-yan

2003, 31(5): 59-61.

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Egg make-ups and milk are added into soymilk to increase the sulfur amino acids and the soybean protein’s absorbability of tofuthus different kinds of tofu are made．The nutritional evaluation results show that by adding egg or milkthe protein content of tofu increases20％～30％ and the nutritional value of new tofu products is improved．

On the Oscillation of Solutions of Certain Second Order Nonlinear Difference Equations#br#

Xu Jian-min Tan Man-chun

2003, 31(5): 62-64,69.

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Some new criteria of oscillation or non-oscillation are presented for certain nonlinear second order difference equations．Several examples are given to illustrate the results．

Simulation of Artificial Neural Networks for Bearing Strength of Concrete Subject to Local Compression#br#

Li Can-feng Cheong Ionman Han Da-jian

2003, 31(5): 65-69.

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The nonlinear behavior and stochastic features for concrete in an anchorage zone or called an end block subject to local compression loading and under complex stress state are briefly reviewed．Results of experimental study for4groups of specimens are introduced．Parameterssuch as the stiffness of the end platesthe ratio of the compres-sion areasand the reinforcement effects are considered．Theses results are used as learning samples for training an artificial neural network（ANN）．By selecting network architecture with sufficient training and testingan ANN model with necessary accuracy for predicting the bearing strength of concrete is obtained．An application example shows that ANN can be used as one of approaches for predicting bearing strength of concrete subject to local compression．

Hierarchical Complex Lapped Transform for Disparity Estimation

Bi Ling-yan Yu Ying-lin Chan Kwok-ping

2003, 31(5): 70-74.

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One important problem in the stereo sequence is disparity estimation．We propose a new method for dispar-ity estimation in this paperin which the hierarchical complex lapped transform phase correlation is used．The results show that this method can overcome the shortcoming of traditional methodimprove the smoothness of the disparity mapreduces the computation complexity of disparity estimation．

Chaos Controlling in Modified Chua’s Circuit

Wang Jia-qing Wang Shao-hua

2003, 31(5): 75-78.

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The chaos control schemes for a modified version of Chua’s circuit are studied to control the chaotic trajectory to a periodical motion．Applying the extern feedback control methodwe design two different control lawsand add the input control signals to the first and the third equations respectively．The result shows thatwith appropriate linear control law and appropriate control strengthwe can successfully control the chaotic motion of the circuit．

Influence Analysis of Prestress on Mechanical Performance of Beam String Structure#br#

Chen Han-xiang　 Shu Xuan-wu

2003, 31(5): 79-84.

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The character and mechanical performance of beam string structure are introduced in this paper．Static analysis is conducted on an example by a current finite element program．The effect of prestress of the string on the mechanical performance is studied in detailwhich provides reference for project design．

Sulfate Resistance of Mortar and Concrete with Slag Addition

Liang Song 　Mo Ha- i hong 　Chen You-wen 　Ru Jian-hui

2003, 31(5): 85-89,96.

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Force density method is frequently used for form-finding of tensioned membrane structure．In this paper the use of “T-element” in force density method is discussedmeanwhiledirection of cable net and the effect of prestress of fixed cable in “T-element” on braced structure are also studied．In additionforce density method is perfected in this paper．

Applying Uniform Design to Genetic Algorithm

Zou Liang　 Wang Guo-qiang

2003, 31(5): 90-92.

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A method of applying uniform design to genetic algorithm for producing the initial population is introducedin this paper．The paper also indicated that because the crossover of GA depended on the initial population of GAthe diversity of the initial population is very important to the convergence of GA．Using the validating method that brought forward by De Jong the paper validated that the method of applying uniform design to genetic algorithm could boost up the convergence of GA．

Sulfate Resistance of Mortar and Concrete with Slag Addition

Liang Song Mo Ha- i hong Chen You-wen Ru Jian-hui

2003, 31(5): 93-96.

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The influence of water -binder ratio and slag content on the ability of sulfate resistance of mortar is studied by experimentsand then the influence of slag addition on the ability of concrete is investigated．The results show that the ability of sulfate resistance of mortar increases only when the replacing ratio of general slag is over65％ or the ratio of slag with excitant is less than50％．By adding general slag with the replacing ratio of65％or slag with excitant with the replacing ratio of50％the ability of sulfate resistance of concrete increases．

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