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    25 December 2005, Volume 33 Issue 12
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    Investigation into Polymer Films as Field Emission Cathode Conditioned by Electric Discharge
    Peng Jun-biao Cheng Lan Lai Guo-hong Cao Yong
    2005, 33(12):  1-4. 
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    The characteristics of the field electron emission of four polymer films(PANI-CSA:polyaniline-camphor sulfonic acid,PEDOT:poly(ethylenedi0xythiophene),PVK:poly(N-vinyl-carbazole)and PMMA:poly(methyl methacrylate))conditioned by the electric discharge were investigated in this paper.During the investigation.the four films were first prepared by coating the corresponding solutions on ITO (indium tinoxide)glass,which were
    next used as the field emission cathode after the superficial treatment by electric discharge in a vacuum testing case.The threshold voltages,curent and voltage I-V characteristics and coresponding Fowler-Nordheim(F-N)plots of the four films were then compared each other,and the conductivities were finally tested to find out how the conductivity influences the electric discharge effect.Experimental results indicate that,in an electric field,the electron emis.sion ability of polymer film has larger conductivity after relates to the conductivity,and becomes stronger when the polymer film conditioned by electric discharge.

    Efect of M icrowave on Reaction Activation Energy of Phenol Degradation by Fenton Reagent
    Xu Ke-feng Li Zhong Wei Shuai Xia Qi-bin
    2005, 33(12):  5-9. 
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    This work aims at the degradation of phenol in wastewater by Fenton reagent in microwave field.The degradation experiments were carried out respectively in microwave field and in normal condition,and the corre-sponding reaction kinetic curves were obtained,which were divided into two stages respectively according with the second-order and the first-order rate equations.The effects of reaction temperature and microwave power on the total organic Carbon(TOC)removal were then discussed,and the reaction activation energies were finally estimated.The results show that(1)microwave radiation not only obviously improves the reaction rate and the TOC removal,but also reduces the reaction activation energy;(2)when the microwave powers are 1 00,200 and 600 W,the cor-responding reaction activation energies at the first stage are respectively 9.833,9.139 and 8.579 kJ/mol,and those at the second stage are respectively 28.245,27.560 and 26.710kJ/mol,which are all less than the values in nor-mal condition(10.782kJ/mol in the firs t stage and 30.294kJ/mol in the second stage);and(3)the reaction acti-vation energy decreases with the increase in microwave power.

    Phase Behavior and Curing Kinetics Characteristics of PPE/TAIC System
    Tian Yong Pi Pi-hui Wen Xiu-fang Cheng Jiang Yang Zhuo-ru
    2005, 33(12):  10-13,24. 
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    The phase diagram of PPE/TAIC(poly(2,6-dimethy-1,4-phenylene ether)/triallylis0cyanurate)sys-tems is analyzed in this paper.The results show that(1)the system possesses an upper critical solution tempera-ture f UCST)behavl 0r and its phase separation is completely reversible in all investigated blends;(2)the curve ofthe vitrification point( )intersects with that of the cloud point at a PPE content(mass fraction,below the same)
    of about 60% ;and(3)when the PPE content is less than 60%,the value of Tg of the system is about 323 K,andwhen the PPE content exceeds 60% ,the system becomes homogeneous and no phase separation occurs in the wholetemperature range.Moreover,according to the experiments caried out by the atom force microscope(AFM)andbased 0n relevant inferences.the cured PPE/TAIC system possessing a morphology via the reaction-induced spinod-al decompositi0n exhibits good chemical resistance.The curing reaction and curing kinetics characteristics of PPE/TAlC svstem are also investigated by FTIR spectra and the program-heated DSC method,focusing on the practicalfabrication process of a copper clad laminate.

    Performance and Structure of Composite Zeolite / TiO2 Photocatalyst with Ultrasonic Treatment
    Ming Cai-bing Wu Ping-xiao Ye Dai-gi
    2005, 33(12):  14-18. 
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    The photocataiytic degradation of exhaust gas containing toiuene was conducted by using the zeoiite / TiO2 composites with and without uitrasonic treatment as the photocataiysts,and the infiuence of uitrasonic treatment on the photocataiytic performance and structure of zeoiite / TiO2 composite was investigated by means of XRD and IR. The resuits indicate that the uitrasonic heips reduce the size of TiO2 nano-particies and causes the bonding reaction of TiO2 with the structure hydroxy in zeoiite,thus resuiting in the improvement of the photocataiytic activity of zeoiite / TiO2 and the degradation rate of toiuene under the action of zeoiite / TiO2 composite.

    Oxidation Pre-TreatInent of Yeast Wastewater by Fenton Reagent
    Zhang Ya-ping Wei Chao-hai Wu Chao fei Wang Wen-xiang Qian Zhan
    2005, 33(12):  19-24. 
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    The 0xidation pre-treatment of yeast wastewater with high colour,salinity and CODCrwas carried out u-sing Fent0n reagent.By investigating the composition variation of the wastewater,it is found that the CODCr and the colour rem0val 0f the wastewater decrease respectively from 15700mg/L to 3 lOOmg/L and from 1600 units to 16 u-nits when the 0xidati0n pre-treatment is carried out at 25 oC for 90 min,with an initial pH of 2.5,a H2 O2 mass con-centrati0n 0f 600 mg/L and a Fe mass concentration of 200 mg/L,while the BOD5/CODCrratio increases from 0.17 t0 0.46. M0re0ver,a linear relationship between the colour removal and the CODCr is revealed.The results of GC/MS analvsis indicate that the chemical oxidation by Fenton reagent changes the structures of some refractory substances such as caramel,melanoidins and polyphenol,thus making the biodegradation feasible.

    Production of Astaxanthin by Phaffia rhodozyma in Bioreactor
    Zhu Ming-jun Du Shun-tang Wang Ju-fang Liang Shi-zhong
    2005, 33(12):  25-28. 
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    High cell-density cultivation of Phaffia rhodozyma for the production of astaxanthin was carried out with an optimized medium in a 5-L stirred bioreactor in two stages.The early stage was mainly devoted to a rapid growth of the yeast cell,while in the later stage,when the cell content reached a certain level.urea was fed to promote the production of astaxanthin,thus improving the yield of astaxanthin.The following results are thus obtained:cell dry
    weight,30.8 g/L,the yield of astaxanthin,28.1 mg/L(calculated as the mass of astaxanthin in unit.volume fer.mentation liquid),astaxanthin content,923.2 Ixg/g(calculated as the mass of astaxanthin in per gram of dry cell) and the yield of biomass to molasses,0.359.This research has laid a foundation for the scale-up production of astaxanthin by Ph~ffia rhodozyma.

    Graded Purification and Structure Analysis of P0lysaccharides from Morinda officinalis How
    He Chuan-bo Chen Ling Li Lin Guo Si-yuan Li Bin
    2005, 33(12):  29-32,51. 
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    Th is paper aims at the graded purification ficinalis How.During the investigation,the Morinda and structure analysis of the polysaccharides from Morinda ofofficinalis How polysaccharides(MOHPs)were first obtained bv the extraction with hot water and subsequently by the precipitation with ethanol.Then,four polysaccharide frac-tions named respectively MOHP-Ⅰ,MOHP-Ⅱ,MOHP-Ⅲ and MOHP-Ⅳ were isolated by means of Anion-Ex-change Chromatography and Gel Filtration Chromatography.Finally,the structures of MOHP-Ⅰ and MOHP-Ⅲ were Dreliminarily analyzed by means of FT-IR,UV-IR,LPC and GPC.The results show that MOHP-Ⅰ is a polysac-charide composed of glucose and fructose,with a molecular mass of 2 ku and a typical structure with furan ring,and that MOHP-Ⅲ is a protein.bound polysaccharide composed of arabinose,xylose,glucose,fructose and galac‘
    tose.with a molecular mass of 35 ku.It is also demonstrated by the results of high-perform ance Gel Perm eation Chromatography that MOHP-Ⅰand MOHP-Ⅲ can both be isolated with a high purity.

    Synthesis and Antimicrobial Activity of Mono-Furfuryl Sodium Fumarate
    Li Yah Gao Jian-hua Ning Zheng-xiang
    2005, 33(12):  33-36. 
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    A new water-soluble preservative withα，β-unsaturated carbonyl groups,namely mono-furfuryl sodium fumarate,was synthesized,whose antimicrobial activity was also investigated.During the synthesis,mono-furfuryl maleic ester was first prepared by the esterification of maleic anhydride and furfuryl alcohol with the same molar of substance at 90 oC for 2.5 h.Then,aluminum chloride anhydrous was added and mono-furfuryl fumarate was pre-pared by the reaction at 90℃ for 4 h.The product was finally obtained by the reaction of excessive mono-furfuryl fumarate with sodium carbonate solution in boiling condition.The results of antimicrobial study show that the inhibi-tion from the growth of common bacteria and mold by mono-furfuryl sodium fumarate is remarkably strong but is rel-atively weaker to yeast.Moreover,mono-furfuryl sodium fumarate can effectively prolong the adaptive phase of milk spoilage bacteria and decrease the growth quantity,with an effect better than sodium benzoate.

    Flow Properties and Energy Dissipation of Medium-Consistency Pulp in Shear Condition
    Chen Qi-feng Chen Ke-fu ya Ren-dang Li Jun
    2005, 33(12):  37-41. 
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    This paper studies the flow properties and energy dissipation of medium-consistency(MC)pulp SUS-pension in rotary device.The results indicate that(1)MC pulp suspension is of similar flow properties to waterwhen it displays fluid·like behavior(fluidization)in rotary device under high shear stress;(2)the energy dis-sipation of MC pulp suspension can be estimated by the temperature change during the fluidization;(3)be-cause of the large friction among fibres,the energy dissipation occupies a high ratio to the input energy duringthe fluidization,being disadvantageous to the pumping of MC pulp suspension;and(4)the apparent viscosityof the pulp suspension with a mass fraction of 13.2% is 7.94 Pa·s.and the corresponding energy dissipation
    is 498.96 kW/m,which is 45.62% of the input energy and increases with the mass fraction of the suspension.

    ANN-Based Dynamic M odeling of Wastewater Treatment Process in Paper M aking by W aste Paper
    Li Di Tang Hui Wan Jin-quan Ma Yong-wen
    2005, 33(12):  42-45. 
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    This paper aims at exploring the possibility of building a dynamic model by artificial neural network for the wastewater treatment process in the paper making by waste paper.During the investigation,the error BP(Back Proragation)neural network is used to establish a dynamic model and describe the complex relationship among the COD of the influent wastewater,the dosage of the added medicament,the flowrate of the influent,the historical COD of the efluent and the predictive COD of the efluent.Different training methods for the network are then com-pared and discussed,demonstrating that the training method with dynamic adjustment results in good consistency between the calculated ouputs and the practical ouputs.The proposed model is finally applied to the wastewater treatment of a paper mill,with the results verifying the effectiveness of the BP model for the dynamic description of
    wastewater treatment.This model lays a foundation for the further investigation into the on-line intelligent control of the wastewater treatment system.

    An 802．1 1 DCF-Based Power-Saving Protocol for Ad Hoc Networks
    Li Ning Xu Yan Xie Sheng-li
    2005, 33(12):  46-51. 
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    To extend the usage scope of an 802.1 1 DCF-based wireless LAN power-saving MAC protocol 802.1 1 PS to a multi.hop mobile environment,a modified version called 802.1 1 NPS is proposed.It applies a packet-driven dynamic switching.of mechanism to the wireless network interface card to save power.By delaying the switching operations after the nodes receive unrelated control packets,802.1 1 NPS can excellently support the upper-layer
    routing protocol.It does not need the global synchronization and can also be used in fully-connected networks.Mo‘ reover,by using a more accurate power-consumption model,the performance of 802.1 l NPS is studied by simula-tion.The results show that.within the simulated scenarios under consideration.802.1 1 NPS can save power by 60%at its maximum in a fully-connected network and by 18% at its maximum in a multi-hop mobile ad hoc network,and that 802.1 l NPS is of a similar throughput to 802.1 l DCF and is of better delay perform ance than the latter.

    Analysis and Kernel Expression of Wire Antenna with Arbitrary Shape
    Kadhum Al-Majdi Hu Bin-fie Yin Jun-Xun
    2005, 33(12):  52-55. 
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    By combining the electric-field integral equation with the moment method,an efficient numericalprocedure for treating the problems of wire antenna with arbitrary shape can be developed. In this paper,the wire antenna with arbitrary shape is analyzed and discussed,and the solution to the current is obtained by using the moment method.Moreover,the exact kernel expressions of Green functions in the integral equation are presented for the solution to the current of wire structure with arbitrary shape.Finally the numerical results and comparisons are perform ed,verifying the efficiency and accuracy of the proposed method.

    Application of Computing Grid to 3 D Simulation of Robot
    Zhang-Ping Wang Qiong-fang Song Bing-lin
    2005, 33(12):  56-60. 
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    A 3 D graphics simulation system for robot is developed based on the computing grid technology, which is then applied to the dynamic simulation of a PUMA560 industrial robot.The results show that. compared with the traditional simulation technologies.the computing ability of the proposed system is greatly improved because of the introduction of the computing d technology,and that the problem of large occupation of computer resources resul.ring from the real-time computations of robotic dynamics and collision detection is effectively solved, thus improving the performance of the 3 D graphics simulation system for robot

    Case Base M aintenance of CBR System Based on Case Cover Capability and Case Fitness Degree
    Tang Ting-xiao Liu Yong Huang Xiang Liao Wen-he
    2005, 33(12):  61-65. 
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    In a Case-Based Reasoning(CBR)system,the case learning makes the case base expand quickly,which results in the redundancy of the case base and the decrease of the searching eficiency.Thus,the system function is weakened.To SO]Ve this problem.this paper analyzes the traditional methods of case base maintenance and proposes a case-saving strategy based on case cover capability to limit the infinite expanding of the case base.Moreover,a case fitness function is defined to describe the subsistence of a case in the base,by which some cases with small fitness degree aye deleted.Therefore,the storage structure of the case base is optimized and the system performance is improved.A CAD system of punch die design is finally presented to verify the correctness and the rationality of the proposed method.

    Trafic Forecasting of M obile Telephone Based on Adaptive Optimized Fuzzy Logical System
    Ynng Ping Chen Wu
    2005, 33(12):  66-69. 
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    It is difficult to correctly forecast mobile telephone traffic data by the traditional method because of the strong nonlinearity of the data.In order to overcome the difficulty,this paper proposes a new approach to forecast mobile telephone traffic data.According to the characteristics of mobile telephone traffic,the mobile telephone traffic data is divided into two parts:the periodic traffic modeled by the first closest clustering method and the trend traffic modeled by the liner regression method.Hereby,an adaptive optimized fuzzy logical forecasting system is de’ signed,which is then tested by all data in a mobile telephone system of Guangdong Province.The testing results show that the proposed system iS effective in the forecasting of mobile telephone traffic.

    SUE Model Based on Multi-Type Vehicles＆ M ulti Criteria and ItsApplication to Toll Allocation
    Liu Wei-ming Huang Ya-fei
    2005, 33(12):  70-74. 
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    In order to overcome the dificulty in toll allocation resulting from the variable driving paths of road users in link-additive toll charge network,this paper proposes a stochastic user equilibrium(SUE)model based on multi-type vehicles and multi criteria.in which the relationship between the toll charge and the entry-exit point＆ vehicle type is taken into account.According to the entry-exit flow in the network,the link flow can be estimated and the toll allocation can be carried out by the proposed SUE model.Moreover,some practical link flows can be used to adjust the coefficient of the model.The results of the numerical example indicate that the proposed method is practi-cal and efective,and can achieve toll allocation validly.

    Semi-Active Suspension System of Train Based on Nonlinear Neural Networks
    Ding Wen-si Bu Ji-ling
    2005, 33(12):  75-77,91. 
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    In order to improve the lateral ride quality of train without endangering safety,this paper illustrates a lat-eral semi-active suspension system based on the skyhook rule.A controlling model of the proposed system is then put forward based on n0nlinear neural networks,with a neural identifier and a controller being also designed.The simulated and tested resuhs show that.compared with the status without any controlling step,the peak of lateral ac-celerati0n of the semi-active suspension system controlled by neural networks decreases obviously,and that the lateral ride quality of train is efectively improved,with the lateral ride item (the value of )being improved by 9.04% in the simulation and 15.9% in the actual testing.

    Design of Asphalt Overlay M aterial Used on Concrete Pavements
    Wang Duan-yi Zhang Xiao-ning Wang Shao-huai
    2005, 33(12):  78-83. 
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    According to the concept of designing material and the modem material design method,a kind of asphalt Overlay material FAC used on concrete pavements was designed.The whole design process includes the evaluation of the mechanics environment and the using condition,the determination of the design principles,the implementa-tion of the material design as well as the evaluation of the FAC perform ance.Moreover,the discrete element method was applied to the analysis and verification of FAC,based on which a simulative test was developed.The results of
    application of the material to several projects and the experience of three-year investigation show clearly that FAC is of optimal perform ance，and that the proposed design method and the procedure are both feasible.

    Evaluation of Anti-Wheel-Rutting Performance of Asphalt Mixture by Using W heel-Rutting Index
    Peng Bo Yuan Wan-fie Chen Zhong-da
    2005, 33(12):  84-86. 
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    Wheel-rutting index(WRI),a new index for evaluating the whole-term high-temperature stability of as.phah mixture is presented by taking into account all the factors affecting the high-temperature perform ance, such as the velocity,the cumulate deform ation and the maximal permanent deformation. and the analysis and comparison of the degrees of track ruts in different periods are then carried out.The results show that the index of DS is not satis-factory because it overlooks the maximum deform ation and the maximal perm anent deformation in the whole Drocess.Thus,it is quite limited in use in the evaluation of the high-temperature perform ance of asphalt mixture. On the contrary ,WRI accords well with the regular patterning of rut formation in practice, and that it shows an effective distinction in the evaluation of the high-temperature stability,without causing the unreasonable occurrence in which the high-temperature perform ances are obviously different while the dynamic stabilities remain similar.

    Nonlinear Aerostatic Stability of Long-Span Concrete-Filled Steel-Tube Arch Bridge
    Yan Quan-sheng Li Li-jun
    2005, 33(12):  87-91. 
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    The analysis for the aerostatic stability of the long-span concrete-filled steel·tube arch bridge-with an in-crement iteration approach is presented.The nonlinear efects of the aerostatic load and the structural geometry are considered in the analysis,and a computing procedure iS then developed.By analyzing the aerostatic stability of the Maocaojie Bridge with a main span of 368 m,the effects of the parameters such as the nonlinearity of the aerostatic load,initial attack angle and the rise-span ratio an d lateral bracing on the lateral aerostatic stability of long‘span concrete-filled steel-tube arch bridges are finally discussed.

    Reliability Evaluation of Dielectric Si3 N4 Based on GaAs M M IC
    Li Bin Lin Li Huang Yun Niu Li-rong
    2005, 33(12):  92-95,104. 
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    The breakdown characteristics of dielectric Si3 N4 based on GaAs MMIC(Microwave Monolithic Integrat-ed Circuit)were studied by using the ramped voltage-accelerated testing.The effects of the area and perimeter of capacitor,as well as the ramped rate on TDDB(Time Dependent Dielectric Breakdown)characteristics were also investigated.The results indicate that a greater area or a longer perimeter will result in more defects in the dielec-tric,thus causing much lower breakdown voltage and poorer reliability.According to the results of the ramped volt-age-accelerated testing with different ramped rates,the lifetime of silicon nitride capacitor at a normal working volt-age was finally predicted based on the TDDB linear field model.It is concluded that,compared with the tempera-ture-accelerated testing,the proposed method is of much faster speed and lower cost.

    Expressions of Acoustic Nonlinearity Parameter of Organic Liquid and Organic Liquid M ixture:Derived from Ultrasonic Velocity-Collision Factor Theory
    Lu Yi-gang Zhang Yang
    2005, 33(12):  96-99. 
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    Based on Schaafs’ultrasonic velocity-collision factor theory and in view of the relationship between the collision factor and the temperature and pressure of liquid,this paper deduces the expressions of acoustic nonlinear-ity parameter in organic liquid and organic liquid mixture.These expressions reveal the relationships between B/A parameter and the aspects such as the molecular repulsion force exponent and thermodynamic parameter of each component,as well as the external temperature and pressure of the medium.Thus,the B/A parameter of organic liquid mixture can be predicted without knowing the B/A parameter of each component.In addition,the internal con-struction information of organic liquid mixture can also be obtained by measuring the B/A parameter of the mixture.

    Threshold Investigation of Ultrasonic Cavitation in Supercritical Fluid CO2
    Yang Ri-fu Qiu Tai-qiu Luo Deng-lin
    2005, 33(12):  100-104. 
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    Aiming at exploring the possibility of the formation of ultrasonic cavitation in supercritical fluid CO2,the laws of cavitation threshold varying with the original radius of cavitation bubble,the pressure and the temperature were investigated,based on the basic theory of cavitation threshold and the thermophysical values of supercritical fluid CO2.The results indicate that(1)the threshold of ultrasonic pressure PB and the threshold of ultrasonic inten-sity,B in supercritical fluid CO2 decrease with the increase in the original radius;(2)higher pressure and lower temperature are propitious to ultrasonic cavitation;and(3)the theoretical cativation threshold in supercritical fluid CO2 is lower than the theoretical and actual ones in water.

    Power Network Planning of Large-Scale Units Accessed to Power Systems Based on Layers and Zones
    Zhong Qing Zhu Ran Ren Zhen
    2005, 33(12):  105-108. 
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    The development of power network in China has entered the new stage of bulk power network interconnection and trans-regional power network interconnection.It is imperative for the operation of the whole power network to reinforce the network of the receiving system.In the planning of the receiving system,the determination of the voltage level for the access of a large-scale power plant to the power grid is significant to the power and voltage supports of the receiving system as well as to the operation of the inner power network in the receiving system.On the basis of the practical experiences of power system planning,this paper analyzes the advantages of the access of a large-scale power plant to the 500 kV power network,and the problems to be considered.A case study is finally presented to illustrate how to use the principles,such as simplifying the wire connection in power plant,diocrsifi-caring the external powers sources and connecting the network by layers and zones,to determine the voltage level
    for the access of a large-scale power plant to the power grid.

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