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    25 July 2005, Volume 33 Issue 7
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    Electrocatalytic Oxidation of M ethanol on Promoted Pt/C Catalysts
    Liao Shi-jun Ye Li-yan
    2005, 33(7):  1-5. 
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    The electrocatalytic oxidation of methanol on promoted Pt/C catalysts,which were prepared using silico-molybedic acid or phosphotungstic acid as the promoter,was investigated.The efects of preparation methods,ad’ ditives,methanol concentration and reaction temperature on the catalytic activity were then studied by linear scan an d cvclic scan methods.and the catalysts were characterized by XRD and EDS.Th e results show that the Pt-Ru-Mo/C catalyst with the mass fraction of M0 0f 7.87% has 65% higher activity than the commercial catalyst Pt-Ru/C manufaetured by E.TEKCompany,and that the addition of silicomolybdic acid and phosphotungstic acid im-Droves the dispersion of active components,thus significantly enhan cing the catalytic activity and CO tolerance of the catalysts.

    M echanical Analysis of RC Beams Strengthened by Prestressed FRPs
    Guo Xin-yan Huang Pei-yan Zheng Xiao-hong
    2005, 33(7):  6-10. 
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    Bonding prestressed FRPs(Fiber-Reinforced Plates)to strengthen and repair civil engineering structures improves the working eficiency and the force conditions of structures.In this paper,formulae of the virtual pre-stress,the prestress lose and the perm issible prestress on the RC beam strengthened by prestressed FRPs are de-duced based on theoretical analyses.Moreover,the virtual prestress,prestress lose and perm issible prestress of two kinds of prestressed FRP-strengthened RC beams are calculated.The results show that the calculated values of vir-tual prestress are consistent with the experimental results,while the calculated values of prestress lose are slightly less than the experimental results.

    Selective Recovery of Motion Vectors in Error Concealment
    Zhou Zhi-heng Xie Sheng-li
    2005, 33(7):  11-14. 
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    An error concealment algorithm is proposed as a post-processing tool at the decoder side,with the aim of recovering the motion vectors and image blocks lost during the video sequence transmission.For a lost block,the standard deviation of its neighboring blocks is first taken as the measurement to judge whether the block is a texture block or a smooth block.Next,all motion vectors of the neighboring blocks belonging to the texture bloc k are se-lected,whose median value are then used to estimate the motion vectors of the lost blocks.Simulated results show that,compared with the existing traditional algorithms,the proposed algorithm can recover images with higher qua-lity in diferent rates of lost block or different video sequences.

    An Adaptive Deblocking Algorithm Based on M RF
    Xu Zhi-liang Xie Sheng-li
    2005, 33(7):  15-19. 
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    A major disadvantage existing in the BDCT(Block Discrete Cosine Transform)technique is that the de-coded images,especially at very low bit rates,exhibit highly noticeable blocking artifacts near the block bounda-ries.In order to improve the quality of the reconstructed image,an adaptive deblocking algorithm based on MRF (Markov Random Field)is proposed in this paper.As human visual system has the masking characteristic of bloc-king artifacts,a visibility function of blocking artifacts is introduced,and a new adaptive potential function is adjus-ted according to the visibility function of blocking artifacts and the edge inform ation.Experimental results show that the proposed algorithm is of merits in abolishing the blocking artifacts,protect the original edges and saving time.

    An Image Encryption Algorithm with Parameters Controlled by External Keys
    Peng Fei Qiu Shui-sheng Long Min
    2005, 33(7):  20-23. 
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    An image encryption algorithm is put forward based on a method that the initial conditions and iteration time of a chaotic system are obtained from external keys,then image signals are encrypted using the subsequently produced chaotic signals.The simulated results show that the proposed algorithm is a good spatial design algorithm for chaotic keys,and possesses a large space of keys,fairly well encryption effect and excellent security to statistic analyses and different attacks.

    Component-Based Video Player M odel for Network Computers
    Liu Fa-gui Huang Kai-yao Zhang Hui
    2005, 33(7):  24-27. 
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    In order to rapidly develop the embedded systems of network computer information appliances,a video player model with great modularity,reusability and extensibility should be constructed.In this paper,by the con-parison of different video player models,a component-based video player model is put forward according to the special client/server architecture of network computers.The components of the proposed model are then analyzed and
    designed in detail in UML(Unified Modeling Language),together with the illumination of the involved design patterns.Moreover,the characteristics of the proposed model are summarized,with a design method for a video player model adapted to network computer inform ation appliances and its implementation finally being presented.

    Quality Improvement of SSP as the Substrate of Polycrystalline Silicon Thin Film Via ZM R Technique
    Hu Yun-fei Shen Hui Wang Lei Zou Xi-wu Ban Qun Liang Zong-tun Liu Zheng-yi Wen Li-shi
    2005, 33(7):  28-31. 
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    The polycrystalline silicon(Poly-Si)thin film,an active layer of the solar cell,was prepared by means of Chemical Vapor Deposition(CVD)with SSP(Silicon Sheet from Powder)as,the substrate.The ZMR(Zone Mehing Recrystallization)technique was next introduced to improve the smoothness and crystal quality of SSP and to further improve the quality of the thin film.The surface profiles,micro-morphologies and crystal quality of SSP ribbon and Poly-Si film were then investigated by the step profiler,XRD(X-ray Diffraction)and SEM (Scanning Electron Microscopy).It is shown that the surface smoothness of SSP is improved after the ZMR process,and SSP with[3 1 1]preferred orientation tends to grow in[1 1 1]prefered orientation.Moreover,the crystal size of the thin film on SSP ribbon via ZMR is more than 100μm,but there is not yet enough evidence to prove that ZMR greatly improves the crystal quality of Poly-Si thin film.

    Numerical Simulation and Verification of Field Coordination of Heat Transfer in Tube Bundles with Gas Flowi ng in Transverse Direction
    Huang De-bin Deng Xian-he Zhu Dong-sheng Ouyang Ti
    2005, 33(7):  32-36. 
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    The correlation equation between the Nusseh number of heat transfer and the field parameters is derived when gas flow through tube bundles in transverse direction,and the Field Coordination Principle is analyzed and validated by numerical simulation.The resuhs show that the Field Co rdination Principle can also be applied to the complex flow and heat transfer of tube bundles.Moreover,the influences of arrangement mode and tube pitch on the heat transfer are explained by the Field Coordination Principle.It is found that the heat transfer performance varies with the arangement mode and the tube pitch because of the coordination between the velocity field and the heat flow field.

    Cultivation of Aerobic Granular Sludge in Microaerobic Condition
    Lan Hui-xia Chen Zhong-hao Chen Yuan-cai Chen Rong
    2005, 33(7):  37-41,46. 
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    Aerobic granular sludge was cultured in microaernbic condition,that is,with a dissolved oxygen (DO)content in the aeration vessel of 0.2 to 0.7 me/L.Anaerobic granules were chosen as the seed sludge.The variations in the appearance an d size of the anaerobic sludge during the cultivation were observed,an d the varia-tions in the MLSS(Mixed-Liquor Suspended Solid),SV(Sludge Volume),SVI(Sludge Volumetric Index)and VSS(Volatile Suspended Solids)of the flocculent sludge as well as in the volume of the granular sludge were also measured.It is f0und that the an aerobic gran ules are completely disaggregated after a 5-day cultivation.that new granules are formed after a 10-day cultivation,and that the sludge in the reactor is completely gran ulated after40 days.It is also shown that the mature gran ules ale san dy beige,witIl a diameter of 500 to 3000 m,a SVI value of 18.147mL/g,a specific gravity of 1.020g/cm3 ,a mass fraction of the moisture of 95.7% and a mass fraction of the organ ic components of 74.1% .thus resulting in a settling rate of 52 m/h.All these items overmatch those of the conventional activated sludge an d the aerobic granular sludge cultivated in conventional aeration.

    Denitrification Characteristics of an Aerobic Denitrifying Bacterium Pseudomonas C loritidismutans Strain X31
    Ma Fang Wang Hong-yu Zhou Dan-dan Zuo Wei
    2005, 33(7):  42-46. 
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    The denitrification characteristics of an aerobic denitrifier,Pseudomonas chloritidismutans strain X31,Were studied under aerobic conditions.The results show that:(1)the dentitrification process of X31 mainly occurs in the LOG phase of the strain and the major end product of the denitrification is molecular nitrogen,(2)during the denitrification of X31,the pH in the culture medium gradually increases,while the Oxidation-reduction Poten-tial gradually decreases,(3)X31 can co-respire by using nitrate or nitrite and oxygen as the electron acceptor,and (4)nitrite respiration is easier than nitrate respiration,both of which achieve high nitrogen removal rate.It is also shown that X31 possesses a higher tolerance to dissolved oxygen than other aerobic denitrifiers reposed previously,and that,when the initial mass concentration of nitrogen oxides in the cuhure medium is about 1 50 mg/L,the aero-bic denitrification rate of the strain is not obviously affected by dissolved oxygen.

    Factors Afecting Impermeability and Compressive Strength of Mortar
    Pan Li-sha Qiu Xue-qing Pang Yu-xia Yang Dong-fie
    2005, 33(7):  47-51. 
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    Orthogonal experiments were carried out to study the influence of several factors on the impermeability and compressive strength of the mortar.These factors include not only three kinds of water reducers,that is,the modified calcium lignosulphonate high-range water reducer GCL1-3A,calcium lignosulphonate water reducer and naphthalene high-range water reducer FDN,but also dosage of water reducer,water-cement ratio,cement-sand ra-tio and the grade of cement.The experimental results show that water reducers have the most significant influence on the imperm eability and compressive strength,and that greater compressive strength and imperm eability can be obtained by adding 0.4% (mass fraction)GCL1-3A into the mortar with a water-cement ratio of 0．435 and a ce-ment-sand ratio of 1:2.5,and the open porosity and pore homogeneous degree of the mortar respectively reach 1 7.06% and 0.46，while those of the blank mortar is respectively 20.56%and 0.17.Moreover,it is primarily indi-cated that the durability of concrete improves due to the improvement of spatial steric hindrance and electrostatic re-pulsive force which increase the dispersion and anti-coagulation ab ilities.

    Synthesis and Properties of a New Fluoride-Bearing Polyacrylate Emulsion
    Liu Fang Wang Fang-hua Lin Rui-yan Jia De-min
    2005, 33(7):  52-55. 
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    A new fluoride-bearing polyacrylate emulsion was synthesized with the polyacrylate emulsion containing epoxy groups as the main material and m-(trifluoromethyl)aniline as the modifier.The synthesis conditions as well as the structure and properties of the product were also investigated.Th e results indicate that the water absorbability of fluoride-bearing polyacrylate emulsion decreases from 1 1.5% to 8.5% .the tensile elongation at break decreases from 610% to 300% ,while the contact angle，the tensile strength and the modulus at 100% elongation respectively increase from 73°to 78°.3 MPa to 8 MPa and 0.57 MPa to 2.87 MPa.

    Measurement of W elding Current and Voltage for Resistance Spot Welding Inverter
    Cao Biao Huang Zeng-hao Zeng Min
    2005, 33(7):  56-60. 
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    The accurate measurement of welding current and voltage is very important to the exact control of resistance spot welding inverter and welding quality.In this paper.the typical measuring methods for large currents are introduced,and the Rogoswki outer-integral measurement is adopted to obtain the large welding current of resistan ce spot welding in-verter.This method is proved feasible by the an alysis of experime ntal results and the model simulation via Matlab.More-over.the welding current and voltage waveforms under diferent current setting an d diferent welding load conditions are analyzed.with the results showing that the welding current is a kind of direct current with slight pulses,while the weld-ing voltage is evidently pulsed.Thus,the dynamic information of the welding current an d voltage is obtained .

    Knowledge-Sharing M odeling Technology for Enterprise Knowledge Management
    Zhan Pe-zhi Liao Wen-he
    2005, 33(7):  61-66. 
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    Knowledge sharing is one of the most important contents of knowledge management.This paper analyzes the requirements for knowledge sharing modeling and proposes a multi-view based modeling technology for enter-prise knowledge sharing.The proposed model includes four kinds of views:the knowledge resource view,the or‘ ganization view,the process view and the control view,which can be used to describe the knowledge resources,the application scenario and the relations between them. Moreover,the detailed modeling technology ,the problem of knowledge matching searching based on the proposed model and a modeling suppofl software for the modeling tech-nology are presented,along with the application of the software.

    Forecasting of Vibration Fault Series of Stream Turbine Rotor Based on ARMA
    Wu Geng-shen Liang Ping Long Xin-feng
    2005, 33(7):  67-73. 
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    The vibration system of the steam turbine rotor is a definite complex system ,the vibration sequence of which consists of many kinds of frequency components.An integrated and accurate mathematical model is important to the extraction of fault premonition information and the forecasting of faults.In this paper,according to the data in both the horizontal direction and the vertical direction of four typical faults,such as rubbing,loosing,uncountershaft and mass unbalance collected from the Bently experimental set,a ARMA(AutoRegression Moving Average)
    model is built up for the vibration fault series after the stable examination of the random stationary noise item in which both the tendency and periodicity items ale removed.The calculated results indicate that the mean errors of 8 forecasted vibration faults of turbine rotor in half period obtained by the ARMA model are all less than 0.55 ixm,and the determ inistic factors r are all more than 0.99 1 5.This means that the proposed method is of great forecas.ting precision and is effective in the further extraction of fault symptom inform ation and the further forecasting of the developing trend of vibration faults.

    Prediction Control Technology for Active Power Filters Based on Gray Prediction
    Zhang Miao Wu Jie
    2005, 33(7):  74-77. 
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    According to the inherent delay characteristic of digital active power filter(APF),a prediction control method for APF is presented based on the gray prediction,with the aim of effectively compensating the harmonic currents in nonlinear loads.Moreover,a gray prediction model for the harmonic currents is established by means of the gray system theory,which is then applied to a harm onic-compensated device for APF. As compared with the popular non-forecasting control method via simulated experiments,the proposed method is feasible.

    Integral Form-Finding Analysis of Beam-Column-Supported Tension Membrane Structures
    Han Da-jian Su Jian-hua
    2005, 33(7):  78-83. 
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    The form-finding analysis for the beam-column-supported tension membrane structures is carried out by the force densitv method.Th e interaction between the structure and the beam-column supports in the form -finding pmcess is taken into account.Equations f0r the form.finding of the whole system are deduced respectively based on the theories of beam ’s small deform ation and beam ’S finite deform ation. Moreover,the corresponding software for the form-finding analysis is developed.Discussions about the integral form -finding of the membrane structures with beam-column supports are finally given by examples.The results prove the proposed method feasible.

    Influence of a Novel Fuel Additive on Combustion and Exhaust of Gasoline Engine
    Cai Rui-bin Chen Zi-jian Lin Hui-bin
    2005, 33(7):  84-87. 
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    In order to investigate the influence of a new multi.effect fuel additive(code-named MAZ)on the com.bustion and exhaust property of gasoline engine,the function and basic working principle of fuel additives were introduced,and under the same work conditions,a series of ful1.1oad and part-load experiments were performed on an engine test-bench using gasoline with or without the addition of MAZ.Experimental results indicate that the addition of MAZ effectively improves the combustion process of gasoline engine,and the exhausts of CO and HC respectively decrease by 22.9%to 25.2%.11.6% to 19.6% .

    Field Experiments of Anti-Seawater Corrosion Concrete with a Lot of Slag in Tidal Region
    Liang Song Yang Yi-bo Mo Hai-hong Chen You-wen
    2005, 33(7):  88-91. 
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    Field experiments of anti-seawater corrosion concrete with a lot of slag have been carried out for 3 years in tidal region in order to investigate the efect of slag on the durability of the concrete.The experimental results in-dicate that,after 3-year immersion in tidal region,the depth of chloride ion penetration of the anti-seawater corro-sion concrete is only 13%~25%of that of the ordinary concrete,which means better anti-chloride ion ability of
    the anti-seawater corosion concrete.It is also indicated that,considering the economic gains and durability,the suitable fineness of slag powder in the anti-seawater corosion concrete is 420～460 m2/kg,and that less binder is better to the concrete when the concrete compaction is good enough.

    Model and Its Genetic Algorithm for Non-Restraint Location Selection of Urban Freight Transshipping Station
    Zhu Qiang Bu Lei Xu Jian-min
    2005, 33(7):  92-95. 
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    Considering the characteristics of urban freight transportation and the complexity of the consecutive loca-tion selection,the non-restraint location selection problem existing in urban freight transshipping stations is ana-lyzed,on the basis of which an optimized mathematical model to solve the problem is established and the effective genetic algorithm for the model is constructed.In this algorithm,the inlaid fitness function based on the table task or the simplex search is designed,and the genetic operational method ensuring the floating-point coding validity is adopted.Numerical calculation results indicate that the proposed model and algorithm efectively solve the non-re-straint location selection problem existing in urban freight transshipping stations.

    Boundary Feedback Anti-Control of Spatiotemporal Chaos for 1D Linear Wave Equation
    Liu Guo-gang Zhao Yi
    2005, 33(7):  96-100. 
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    In this paper,a 1 D linear wave equation with linear or nonlinear boundary conditions is taken into account.A bo undary feedback controller is designed with a sine function,and is then used to drive an originally non-chaotic linear system chaotic.Moreover,the solution of the controlled system is an alytically expressed by the method of characteristic line.By the theory of total variation and symbol dynamic system,it is proved that the system is chaotic.Numerical simulations are finally carried out to verify the correctness of the proposed con-trolled method .

    Bound of Common Consequent of Primitive Digraphs with Exact d Vertices Having Loop
    Chen Xiao-gen Peng Hong
    2005, 33(7):  101-104. 
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    A digraph G is said to be primitive if there exists a positive integer P such that for each ordered pair of vertices u and ν ,there is a walk oflength P from u to v.Let Pn(d) be the set ofall primitive digraphs oforder n(n≥3)with exact d vertices having loops,LG(k) be the k-common consequent (k-c,c.)of primitive digraph G,2≤k≤n,and L(n,d ,k)=max{LG(k)| G ∈ Pn (d)},In this paper,the bound of k-common consequent,namely,n-「d/2」≤L (n,d,k)≤n-1,1≤d≤n,is obtained.

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