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Table of Content
25 June 2005, Volume 56 Issue 6
    Drug delivery systems
    LIU Xiudong, MA Xiaojun, YUAN Quan
    2005, 56(6):  955-961. 
    Abstract ( 692 )   PDF (524KB) ( 750 )  
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    Drug delivery systems (DDS) have been developed as a new means of releasing drugs with accurate dosage and convenient administration.It will be promising in clinical application with high effectiveness and safety of drugs, and high compliance of patients.In this review, the status quo and progress of main non-injection routes (oral,trans-dermal and mucosal DDS) are summarized.The application of novel technologies such as targeting, cell micro-encapsulation and micro-fabrication in DDS is introduced.Finally, the problems and some strategy to resolve such problems are addressed.
    综述与专论

    Review of nanotube bio-technology

    WU Hong;JIANG Zhongyi

    2005, 56(6):  962-971. 
    Abstract ( 685 )   PDF (1219KB) ( 739 )  
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    With the rapid development of nanotube science, nanotubes are attracting more and more research and application interests in bio-technology due to their unique tubular structure and consequently unique mechanical, chemical, electronic and optical properties.Nanotube bio-technology has become the frontier and hot issue in nano-technology.The main preparation methods, formation mechanisms and characteristics of nanotubes are outlined, and the research progress of nanotubes in bio-separation, bio-catalysis, bio-sensor and bio-medical engineering is briefly reviewed.
    Research progress of flux prediction models of micro-filtration membrane
    WANG Zhan, WU Wenjuan, ZHANG Xinmiao, LIU Dezhong
    2005, 56(6):  972-980. 
    Abstract ( 658 )   PDF (652KB) ( 334 )  
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    The existing micro-filtration flux models are described in three sections.Firstly, the development of the concentration polarization model or the force balance model is reviewed based on the back-diffusion and lateral migration of particles changing with process parameters.Secondly, the blocking mechanisms, the Darcy’s law and their development are introduced based on the adsorption of particles in membrane pore or the characteristics of deposition of particles on membrane surface.Thirdly, the combined model which takes into account the interaction of different factors is reviewed.Meantime, the potential future directions of predicting micro-filtration membrane flux model are discussed.
    Thermodynamics of thermally induced phase separation of iPP-DBP-DOP ternary solution by pseudo-binary approach
    YANG Zhensheng, CHANG Heying, LI Pingli, WANG Shichang
    2005, 56(6):  981-988. 
    Abstract ( 827 )   PDF (1546KB) ( 532 )  
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    The thermally induced phase separation thermodynamics of the ternary solution consisting of isotactic polypropylene (iPP), di-n-butyl phthalate (DBP) and dioctyl phthalate (DOP) was studied by pseudo-binary approach,considering the co-solvents of DBP and DOP as one component.The mathematical model to calculate pseudo-binary temperature-concentration phase diagrams was proposed. The cloud point curves of iPP-co-solvents systems were obtained with optical microscopy at a cooling rate of 1K•min-1.The melting point curves and dynamic crystallization lines of iPP-co-solvents systems were determined with differential scanning calorimetry(DSC) at several cooling rates.The interaction parameter χ between iPP and co-solvents was a function of temperature and co-solvents composition,and was determined from cloud point curves of iPP-co-solvents systems.Good agreement was obtained between the pseudo-binary phase diagrams calculated from the mathematical model and the ones generated from experiments. With increasing DBP fraction in co-solvents, the phase separation of the ternary solution changed from solid-liquid to liquid-liquid with subsequent solid-liquid.By varying the co-solvents composition systematically, the pseudo-binary phase diagrams could be controlled successfully.The thermodynamics of thermally induced phase separation of iPP-DBP-DOP ternary solution could be obtained by only measuring the cloud point curves of pseudo-binary systems of several co-solvents compositions at a lower cooling rate and dynamic crystallization lines of iPP-DOP system at several cooling rates.In the end, it was illustrated that the resulting membrane morphology could be explained successfully with the thermodynamics of iPP-DBP-DOP solution studied via the pseudo-binary approach.
    Gas flow analysis in cyclone separator with a stick
    WANG Jianjun, WANG Lianze, LIU Chengwen
    2005, 56(6):  989-994. 
    Abstract ( 604 )   PDF (677KB) ( 211 )  
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    Laser Doppler velocimetry (LDV) was used to measure the flow field in order to study how a stick reduced the pressure drop in the cyclone separator.According to the characteristics of the flow field, it was found that the stick generated a strong flow wake in the cyclone separator, and different shapes of flow wake resulted from different types of the stick.Experimental results also showed that the size and shape of the stick cross-section made a prominent effect on the strength and shape of flow wake.For the same shape of stick cross-section,the wider the stick cross-section was,the greater the tangential time-averaged velocity and root-mean-square velocity,and the shape of flow wake also changed.While for the same width of stick cross-section, the rectangular stick had a stronger effect on the flow field than the circular one. Because there was a direct relationship between the type of stick and the pressure drop reduction of the cyclone separator, the mechanism of pressure drop reduction could be analyzed by studying the flow wake.
    传递现象

    Performance of enhanced heat transfer tube with discrete double-inclined ribs

    MENG Ji’an;LI Zhixin;GUO Zengyuan

    2005, 56(6):  995-998. 
    Abstract ( 630 )   PDF (472KB) ( 255 )  
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    The numerical and experimental study was carried out for the discrete double-inclined ribs (DDIR) tube developed on the basis of the convective heat transfer field-coordination theory. The experimentally fitted relationships of heat transfer and resistance coefficients were given. The periodical change of the original surface specially designed in the DDIR tube induced multi-longitudinal vortex flow and enhanced heat transfer remarkably with less extra flow resistance.When Re=500—2300,heat transfer enhancement of the DDIR tube would be increased by 2.5—6.5 times with a resistance increase of 120%—300% compared to the laminar heat transfer of a circular tube (L/D=300) considering inlet effect. When Re=2300—104,heat transfer enhancement would be increased by 130%—240% with a resistance increase of 130%—220%.When Re=104—5×104,heat transfer enhancement would be increased by 110%—130% with a resistance increase of 220%—240% compared to the circular tube.There was no flow dead zone in the DDIR tube so fouling could be prevented in the tube.Its manufacture could be more efficient and low-cost, therefore it is a kind of heat transfer enhancement tube with excellent overall performance.

    Model calculation of air water counter flow heat and mass transfer and comparison with experimental data

    SONG Yaozhen
    2005, 56(6):  999-100. 
    Abstract ( 553 )   PDF (434KB) ( 371 )  
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    According to general equations deducted from a model of heat and mass transfer of air and water in direct contact counter flow reported in the author’s previous work,the outlet parameters of air and water counter flow through a paper wet pad were calculated by using the MATLAB-software.Comparing the calculation results with experiment data of prior researchers, the deviation of calculated outlet air wet bulb temperature from experimental outlet air wet bulb temperature was less than 10%,the deviation of calculated outlet water temperature from experimental outlet water temperature was less than 9%,and the deviation of calculated outlet air dry bulb temperature from experimental outlet air dry bulb temperature was less than 10% when NTUh was more than 0.6.The deviation of calculated outlet air dry bulb temperature from experimental outlet air dry bulb temperature was more than 10% when NTUh was less than 0.6.The model calculations were in good agreement with experiments and the general equations could be used to design evaporation cooling equipment,such as wet pad and so on.
    Average holdup in multiphase pipelines with low loads of liquids
    WANG Wuchang, LI Yuxing, TANG Jianfeng, YU Xichong
    2005, 56(6):  1004-1008. 
    Abstract ( 724 )   PDF (533KB) ( 285 )  
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    The experimental study on average holdup in multiphase pipelines with low loads of liquids was conducted on a large multiphase flow loop.The average holdup increased with increasing liquid load and decreased with increasing gas velocity, and also depended on the undulation of pipeline and flow patterns in the pipeline. The effects of eight dimensionless parameters on average holdup were seriated with grey relational degree analysis so as to find the most important factors affecting the average holdup in multiphase pipelines with low loads of liquids. An average holdup correlation based on low liquid loads was also developed and the correlation related the most important three factors including superficial gas velocity number(Ngw), superficial liquid velocity number(Nlw) and liquid Reynolds number(Rel) to the average holdup.Finally the correlation was tested with the field data and the result was satisfying.
    Kinetic model for fulvic acid degradation by TiO2-photocatalysis in water
    FU Jianfeng, JI Min, JIN Luonan, AN Dingnian
    2005, 56(6):  1009-1014. 
    Abstract ( 676 )   PDF (595KB) ( 557 )  
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    Fulvic acid (FA) is a natural organic matter existing in Tianjin surface waters as a major precursor of disinfection byproducts.So fulvic acid control is very important in surface water treatment.Degradation of FA in a photocatalysis-ultrafiltration reactor using TiO2 powder catalyst was studied in terms of UV254 and total organic carbon(TOC)concentration.The key effects of influencing parameters on the photocatalytic oxidation of FA, including pH values, photocatalyst concentration,additives concentration and light intensity were investigated.The results showed the reaction kinetics of FA could be reasonably represented by first-order kinetics.In addition, it was found that there was an optimal catalyst concentration of 0.5 g•L-1 and low pH value.Increasing additives concentration and light intensity were favorable for TOC removal.By analyzing the relationship between rate constant and influencing factors, an overall FA oxidation rate kinetic model was established.The theoretical prediction were in good agreement with the experimental data.This reactor was a convenient way to degrade the organic matter with high efficiency.
    Nitrosation kinetics of cyclohexane-carboxylic acid with nitrosyl sulfuric acid
    LI Zhaohui, LUO He’an, WU Jian, YUAN Xia
    2005, 56(6):  1015-1019. 
    Abstract ( 875 )   PDF (412KB) ( 249 )  
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    The nitrosation of cyclohexanecarboxylic acid (CCA) with nitrosyl sulfuric acid is an important industrial process to produce ε-caprolactam. The experiments showed that there also existed a parallel reaction between CCA and SO3 as well as an intercrossing reaction between caprolactam and nitrosyl sulfuric acid,except for the nitrosation of CCA. A reaction kinetics model of the process was proposed, and the model parameters were indirectly determined by the results from the analysis-synthesis experimental design assuming the reactions in the nitrosation system having no influence on each other.This model not only could explain the control parameters in the industrial process,but also could support the optimization of the industrial process.
    Lumped mechanism kinetics of Fischer-Tropsch synthesis over ultrafine particle Fe-Mn commercial catalyst(Ⅰ) Reaction mechanism and kinetic model description
    JI Yuanyuan, XIANG Hongwei, LI Yongwang, XU Yuanyuan, ZHONG Bing
    2005, 56(6):  1020-1025. 
    Abstract ( 634 )   PDF (424KB) ( 211 )  
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    The objective of this paper is to establish a kinetic model description of CO conversion over the ultrafine particle Fe-Mn commercial catalyst in the Fischer-Tropsch process to provide the design basis for scaling up commercial reactor.Fischer-Tropsch process, including hundreds of reactions, was lumped into two kinds of reactions.One was Fischer-Tropsch reaction, in which the main product hydrocarbons were formed.The other was Water Gas Shift (WGS)reaction, in which the main by-product CO2 was formed. Thus, the reaction rate of CO was approximately expressed as the sum of hydrocarbon formation rate and CO2 formation rate.The description of the elementary step in the hydrocarbon formation was established based on the carbide mechanism.The rate-controlling step in the hydrocarbon formation model was the one controlling the formation of the structure unit CH*2. Meanwhile, the description of the elementary step in Water Gas Shift reaction was found based on the formate mechanism,and the rate-controlling step in Water Gas Shift reaction model was the formation of formate species.The kinetic model description of the Fischer-Tropsch process, including both Fischer-Tropsch reaction and Water Gas Shift reaction, was acquired by the combination of the above two kinds of kinetic models.
    Lumped mechanism kinetics of Fischer-Tropsch synthesis over ultrafine particle Fe-Mn commercial catalyst(Ⅱ) Evaluation of parameter and discrimination of model
    JI Yuanyuan, XIANG Hongwei, LI Yongwang, XU Yuanyuan, ZHONG Bing
    2005, 56(6):  1026-1030. 
    Abstract ( 597 )   PDF (392KB) ( 196 )  
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    The kinetic experiments were designed to acquire the precise kinetic parameters. In the evaluation of kinetic parameters, CO conversion and CO2 selectivity were established as two objective functions. The lumped mechanism kinetic model description candidates of the Fischer-Tropsch synthesis obtained in paper (Ⅰ) were evaluated by the optimization of kinetic parameters with the conventional Levenberg-Marqaurdt method.Then these model description candidates were screened according to the physical meaning of parameters, fitting degree and the statistical examination. Finally, the acquired kinetic models could well describe CO conversion and CO2 selectivity. The errors between the calculated values and the experimental values were generally less than 25%. Meanwhile, the acquired model parameters could reasonably explain the commercial catalyst performance.
    分离工程

    Non-equilibrium stage static simulation of lactic acid purification reactive distillation process

    ZHANG Meng;MA Li;YANG Jichu;XU Yongmao

    2005, 56(6):  1031-1034. 
    Abstract ( 867 )   PDF (666KB) ( 505 )  
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    Purification of lactic acid by reactive distillation (RD) is a novel technology which has many excellent characteristics compared with traditional technologies. This paper presented a non-equilibrium model for lactic acid purification RD pilot column. An Improved Separation Efficiency Function (ISEF) was proposed based on de-coupling and pseudo-homogenous assumptions, which greatly improved the solving efficiency and made this model suitable for practical application. Simulation results were consistent with the experiments in different conditions, and the simulation results outperformed the simulator ASPEN PLUS in which the equilibrium stage assumptions were adopted. The static characteristics of the pilot setup were also investigated.The analysis result could help to accelerate the commercialization of the lactic acid purification RD technology.
    过程系统工程

    Calculation of chemical and metallurgical phase equilibria using genetic algorithms reinforced by generalized reduced gradient algorithms

    ZHANG Huigang;ZHU Qingshan

    2005, 56(6):  1035-1040. 
    Abstract ( 665 )   PDF (470KB) ( 274 )  
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    Since reliable calculations of phase equilibria are very important for chemical and metallurgical processes, studies on algorithms of phase equilibria are of value and interest. In this paper, the generalized reduced gradient (GRG) methods were used to enhance the local search ability of conventional genetic algorithms (GAs). GRG, as an operator, was first introduced to speed up the convergence and at last was used to refine the results of GAs.Because of improved efficiency, higher reliability and flexibility, the hybrid algorithms might have broad application in the calculation of chemical and metallurgical phase equilibria.

    Equivalent gray absorption coefficient obtained by inverse analysis in non-gray gases system

    NIE Yuhong;CHEN Haigeng;YAO Shouguang

    2005, 56(6):  1041-1044. 
    Abstract ( 754 )   PDF (397KB) ( 302 )  
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    An inverse radiation analysis is presented for calculating the distribution of equivalent gray absorption coefficients from the temperature measurement in a non-gray gases system, where radiation conduction and convection occur simultaneously. The energy equation is solved by the zonal method, and the inverse radiation problem is solved through the minimization of performance function with the conjugated gradient method. Taking the measurement results of an experimental furnace as the solution condition, the equivalent gray absorption coefficient distribution is obtained by the presented method. Results show that the zonal method combined with the conjugate gradient method can solve the equivalent gray absorption coefficient well in the non-gray gases system. Comparison with the exponential wide band model shows that the equivalent gray absorption coefficient has the accuracy with the exponential wide band model, while the calculation time is less than a tenth.

    Process monitoring based on blind signal extraction with process information of indeterminate stationariness

    CHEN Guojin;LIANG Jun;QIAN Jixin

    2005, 56(6):  1045-1050. 
    Abstract ( 615 )   PDF (482KB) ( 146 )  
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    Process monitoring based on multivariate statistical projection analysis (MSPA) has successfully been applied to chemical processes. However, measured data are often dealt with as stationary information in industrial processes, which is not a case in fact. In this study, a new process monitoring method based on blind signal extraction and k-nearest classifier is presented, which dose not demand stationary measured data.In order to verify the effectiveness and feasibility of this method, the new process monitoring method was applied to a simple AR(1) process and a double-effect evaporator. The simulation results showed that the process monitoring method presented in this paper had fewer false alarms and missing alarms than that based on independent component analysis (ICA) and fewer false alarms than that based on multivariate statistical process control (MSPC).Therefore, the process monitoring method presented in this paper is more effective and better than conventional process monitoring methods.

    Design methodology for water networks with internal water mains

    WANG Dongming;YANG Fenglin;ZHANG Xingwen

    2005, 56(6):  1051-1056. 
    Abstract ( 767 )   PDF (424KB) ( 379 )  
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    In this paper, a design methodology for water networks with internal water mains for reuse is presented.The new method emphasizes the significance of determining the location of the first internal water main,and discusses how to prioritize allocation of the reuse water to the subsequent processes.In the design step how to resolve special situations that are likely to appear is discussed.Case studies show that the water networks designed by this method can obviously reduce fresh water consumption, and the design procedure can be performed easily.

    New approach to data rectification of hybrid systems

    ZHANG Qiran;RONG Gang

    2005, 56(6):  1057-1062. 
    Abstract ( 740 )   PDF (428KB) ( 340 )  
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    For hybrid systems which incorporate both dynamic and discrete event models in process industries, the models of material balance would be changed because of frequent scheme switch. The redundancy degree of the whole sensor network is time variant so that the traditional data reconciliation methods could hardly be used in practical processes. In this paper a new approach of data reconciliation for hybrid systems is proposed. For those nodes where the discrete scheduling events might happen, scheduling-equations are established and added to the models. So the new data reconciliation model with parameters of random scheduling-equations could be built. In this way, the model’s redundancy is improved, which enhances the solvability of the data reconciliation problem. Then its optimal solution could be obtained by using a reconciliation algorithm with uncertain models. Some simulations of the simplified model for a refinery are given and a comparison is made between the proposed approach and previous researches. The simulations results demonstrate the efficiency and robustness of the proposed method.
    Surfactant assisted protein refolding in vitro:molecular simulation
    LU Diannan, WANG Jun, LIU Zhixia, ZHANG Minlian, LIU Zheng
    2005, 56(6):  1063-1069. 
    Abstract ( 682 )   PDF (627KB) ( 369 )  
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    The molecular interaction between protein and surfactant and its implication on the refolding of the protein in vitro was investigated by using the simple lattice model with dynamic Monte Carlo simulation and canonical ensemble.The thermodynamic feasible status of the model protein, as described by HP model, and its folding intermediates were captured. Some of the folding intermediates were trapped into local energy minimum and could not proceed refolding into the native form. The addition of surfactant enriched both the species and the amount of folding intermediates by the way of forming protein-surfactant complex. The surfactant of weak hydrophobicity had little impact on the thermodynamic status of the protein but was effective in moving the folding intermediates out of local minimum energy entrapment, leading to a considerable increase in the refolding. On the other hand, the surfactant with strong hydrophobicity might block the folding process by forming stable protein-surfactant complex. In this case, the dissociation of the complex by stripping the surfactant was necessary so as to precede the folding process. The synergy of surfactant and denaturing environment for protein refolding was also confirmed. The simulation agreed well with prior experiment results in literature. This indicated the potential of using molecular simulation to explore the details of refolding process and to assist the design of suitable surfactant-like folding aids.
    Flexible immobilization of papain on amino polystyrene support
    SHEN Bin, WEI Rongqing, LIU Xiaoning, ZHU Jianxing, OUYANG Pingkai
    2005, 56(6):  1070-1075. 
    Abstract ( 662 )   PDF (534KB) ( 289 )  
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    In this paper the flexible immobilization model of enzyme is presented.A new amino polystyrene (0.4—6.0 mmol NH2•g-1) was prepared by Mannich reaction as immobilization support, DAS was used as the flexible chain,and then papain was immobilized. The recovery of immobilized enzyme activity could reach 40%—50%,equal to 1.8—2.4 times that of arm spacer support, and the stability of immobilized enzyme was good.The flexible immobilized model could achieve a higher recovery of immobilized enzyme activity than traditional covalent immobilization and arm spacer immobilization.
    Refolding of recombinant human interferon-γ by hydrophobic interaction chromatography
    GUAN Yixin, PAN Haixue, YAO Shanjing
    2005, 56(6):  1076-1080. 
    Abstract ( 868 )   PDF (454KB) ( 374 )  
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    The recombinant human interferon-γ (rhIFN-γ) was overexpressed as inclusion bodies in Escherichia coli. After ultrasonic homogenization and centrifugation, inclusion bodies of rhIFN-γ were obtained. The inclusion bodies were then purified by coupling wash steps in Triton X-100 and finally were dissolved in 8 mol•L-1 urea. A refolding process by hydrophobic interaction chromatography (HIC) was proposed. Refolding methods with no urea gradient and linearly decreasing urea gradient were performed.The effects of final urea concentration, urea gradient length, flow rate and protein loading on the refolding were investigated in detail. Under the optimum condition in the refolding with linearly decreasing urea gradient, the activity yield of rhIFN-γ was 6.5 times of that in the dilution refolding process and the protein mass yield was up to 36% with specific activity 1.9×108 IU•mg-1.
    Transport characteristics of water and proton in membrane of PEM fuel cells
    SUN Hong, GUO Liejin, LIU Hongtan, ZHANG Guangsheng
    2005, 56(6):  1081-1085. 
    Abstract ( 760 )   PDF (579KB) ( 462 )  
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    Water and proton transport together with water content in proton exchange membrane showed significant effects on the performance of PEM fuel cells. A steady state two-phase flow model is presented in this paper to study water transport and water content in the membrane as well as the relation between water content and proton transport resistance. This model couples the conservation of mass, momentum and species equations with transport equation in the membrane. Simulation results indicated that the polarization curves agreed well with experimental data.For the same current density, coefficients of electro-osmotic drag, back diffusion and hydraulic permeation with water content in the membrane increased gradually along the gas flow direction, while net water transport coefficient and proton transport resistance decreased as operating pressure increased;[JP2]at the same time electro-osmotic drag, back diffusion, hydraulic permeation and net water transport coefficients and water content in the membrane increased rapidly, while proton transport resistance decreased,which improved the performance of PEM fuel cells.
    Toxicity and toxicity emission load of reed pulp CEH bleaching effluents
    FANG Zhanqiang, LI Youming, CHEN Zhonghao
    2005, 56(6):  1086-1090. 
    Abstract ( 786 )   PDF (401KB) ( 429 )  
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    The toxicity of CEH bleaching effluents was studied with photobacteria. The toxicity of C stage was the strongest, its EC50 was 17.39%, belonging to the strongest toxicity level. The EC50 of E, H stages were 163.6% and 252.4% respectively. Both belonging to the no toxicity level. The total toxicity emission factor(TEF) of CEH was 472.021 TU•m3•t-1.The TEF of C stage was 393.88 TU•m3•t-1, about 83.45% of the total toxicity emission factor. The TEF of E and H stages was 10.03% and 6.52% respectively.
    Ni,Pt function in catalyst for diesel particulate removal from exhaust gases
    LIANG Hong, YE Daiqi, FU Mingli, XUE Shumin, LIN Weiming
    2005, 56(6):  1091-1096. 
    Abstract ( 588 )   PDF (898KB) ( 261 )  
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    The catalytic oxidation traps of particulate matter(PM) from diesel exhaust gases seem to be one of the best ways because of their simplicity, easy handing, high abatement efficiency and comparatively low cost.The development of catalysts for catalytic oxidation traps is presented. By using monolithic cordierite honeycomb as support which was modified by TiO2,γ-Al2O3,Cu-K-V,catalyst was prepared by the impregnation method and modified by Ni and Pt. The catalyst was aged in a muffle oven in air for 3 h at 700℃ and characterized by BET, TG-IR and activity tested through DSC/TG experiments.The particulate matter combustion temperature at the highest oxidation reaction rate could be lowered remarkably,especially for removing graphitic solid fraction(GSF) in particulate matter.The catalytic performance was improved by adding Ni and Pt. For the aged catalysts modified by Pt, their activity decreased, in contrast, for the ones modified by Ni, their activity increased. The reason could be the migration of Ni from inner layer to catalyst surface during the aging process.
    能源和环境工程

    Startup characteristics of VTE-MED seawater desalination system

    DU Xiaoze;WU Shaorong

    2005, 56(6):  1097-1101. 
    Abstract ( 901 )   PDF (396KB) ( 461 )  
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    The control model for dynamic startup process of the vertical tube evaporator(VTE)-multi-effect distillation(MED) seawater desalination system was established by using a developed code based on the non-linear differential equations for system design and performance analysis.Theoretical investigation of the startup characteristics was conducted with the numerical method.The influence of the operating parameters, such as initial feed brine flow rate and top brine temperature,on the startup process was analyzed. The coupling effect of feed brine flow rate, GOR and startup time were also investigated as the evidence to determine optimal initial feed brine flow rate. The results also indicated that the system could consume the total rated heat generated by the low temperature nuclear heating reactor (LT-NHR)even at the most initial startup stage, implying that the present desalination system demonstrated excellent coupling characteristics with the LT-NHR. With necessary experimental verification, the startup control model developed in this paper could be the theoretical basis for the analysis of dynamic performances of seawater desalination system.

    Effective proton conductivity of catalyst layers in proton exchange membrane fuel cells

    DU Chunyu;SHI Pengfei;CHENG Xinqun;YIN Geping

    2005, 56(6):  1102-1105. 
    Abstract ( 831 )   PDF (578KB) ( 328 )  
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    A numerical model was presented to predict the specific proton conductivity of the catalyst layer in Proton Exchange Membrane Fuel Cells (PEMFC).This model was derived from the random packed spheres with simple cubic, body-centered cubic and face-centered cubic structures.The effects of sphere radius rs, bulk proton conductivity kb, contact parameter γ and contact angle α on proton transfer within a homogeneous agglomerate sphere consisting of carbon-supported catalyst and electrolyte were analyzed.A correlation equation of specific proton conductivity was obtained by data fitting.The real effective proton conductivity in the catalyst layer was measured by addition to a standard Membrane Electrolyte Assembly of an inactive composite layer in the electrolyte path between the anode and cathode. The model was validated by good agreement between calculations and measured data.
    材料科学与工程

    Influence of synthesis condition on magnesium hydroxide properties by two-step reaction on pilot scale

    LI Zhiqiang;WU Qingliu;XIANG Lan;WEI Fei

    2005, 56(6):  1106-1111. 
    Abstract ( 769 )   PDF (2033KB) ( 560 )  
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    In order to resolve the problem that Mg(OH)2 is incompatible with the polymer, the two-step reaction of Mg(OH)2 preparation, synthesis reaction and hydrothermal modification, is one of the useful techniques. In this study, the synthesis reaction conditions of MgCl2-NaOH route were investigated in a large-scale experimental set-up designed by authors, with focus on the influence of synthesis temperature and NaOH solution feeding rate on the morphology, particle sizes, crystalline structure and dispersion properties of the synthesis products and hydrothermal products. The regular hexagonal plates of Mg(OH)2 with a larger particle size and a smaller specific area were formed after hydrothermal treatment.The dispersion properties of the hydrothermal products were improved owing to the alteration of growth direction for Mg(OH)2 crystals, resulting in the increase of I(001)/I(101). Under the experimental conditions, the increase of synthesis temperature and decrease of NaOH solution feeding rate were favorable to improving the morphology and dispersion properties of the synthesis products and hydrothermal products owing to the damage of the adsorption layer on the crystal surface.
    Synthesis of new ionic liquids and corrosion inhibition performance of its cationic imidazoline group
    SHI Shuncun, YI Pinggui, CAO Chenzhong, WANG Xueye, SU Jieshu, LIU Junxi
    2005, 56(6):  1112-1119. 
    Abstract ( 850 )   PDF (1066KB) ( 553 )  
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    A series of new ionic liquids Ⅰ—Ⅴ with imidazoline ring were synthesized from highly pure naphthenic acids.The relationship between the alkyl connecting with N(3) of imidazoline ring and corrosion inhibition performance was investigated.The corrosion inhibition performance was measured by using the mass loss method and electrochemistry method for carbon steel samples in acidic solution.The quantum chemistry method and polarizablity effect index method were used to calculate the parameters such as front molecular orbit energy and corresponding PEI of cationic imidazoline group of ionic liquids Ⅰ—Ⅴ.Measured results and theoretical analyses indicated that corrosion inhibition efficiency of the cationic imidazoline group of ionic liquids Ⅰ—Ⅴ was decreasing as in following order:Ⅴ>Ⅳ>Ⅲ>Ⅱ>Ⅰ,and the corrosion inhibition efficiency had a good linear relationship with the such parameters as EHOMOEL-H and PEI.
    Synthesis and characterization of polystyrene-g-polydimethylsiloxane copolymers
    XU Yongshen, DAI Jianhua, ZHANG Minlian, YUAN Caideng
    2005, 56(6):  1120-1123. 
    Abstract ( 992 )   PDF (531KB) ( 401 )  
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    Polystyrene-g-polydimethylsiloxane copolymers were prepared by using the methacryloxypropyl-polysiloxane(PDMS-MA) macromonomer technique.The structures of graft copolymers were characterized by Fourier transform infrared(FTIR) spectroscopy.The influence of molecular mass of PDMS-MA on copolymerization activity was investigated.Thermal properties of the graft copolymer were also studied.The reactivity of PDMS-MA decreased with increasing molecular mass. Meanwhile with increasing ratio of PDMS-MA to styrene, the copolymerization conversion of PDMS-MA decreased. The heat-resistance of PSt-g-PDMS was improved comparing to PSt alone.The improvement was greater when the molecular mass of PDMS-MA and its contents were increased.
    材料科学与工程

    Distribution of inorganic crystal particles in carnallite

    ZHANG Wanping;WANG Xiangtian;SONG Xingfu;YU Jianguo

    2005, 56(6):  1124-1129. 
    Abstract ( 612 )   PDF (1210KB) ( 539 )  
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    Particle size, surface composition and crystal configurations of Kvarkhan’s carnallite were investigated. Particle sizes and composition were determined by sieving and chemical analysis. The results showed that more than 90% of KCl•MgCl2• 6H2O crystal particles were larger than 0.177 mm, more than 75% of NaCl particles were smaller than 0.125 mm, and more than 90% of CaSO4 particles were smaller than 0.074 mm. Surface compositions were studied by X-ray diffraction analysis. Ca/Na of carnallite components were determined by X-ray photoelectron spectroscopy. The results of scanning electron photomicrograph and energy-dispersive X-ray analysis demonstrated that all those crystal particles were present independently in carnallite.

    Short carbon fiber reinforced aluminum matrix composites

    GAO Song;YAO Guangchun

    2005, 56(6):  1130-1133. 
    Abstract ( 608 )   PDF (963KB) ( 629 )  
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    The aluminum matrix composites reinforced by short carbon fiber were prepared in non-vacuum furnace by the method of liquid state mechanical stirring casting.The C/Cu composite fiber was treated with H3BO3 after the carbon fiber was coated with copper in the electroless plating and electro plating process.The effects of dispersion of carbon fiber in the composite, existing state of copper plating and tensile properties of the composite were investigated. The results showed that the oxidation rate of copper decreased obviously and carbon fiber was uniformly dispersed and undamaged in the composite.The mechanical properties of the composite were not influenced by the H3BO3 added.The tensile strength of the composite increased with the increasing content of carbon fiber, which was 50% higher than that of the matrix material. However, the plasticity of the composite decreased obviously.

    Preparation and biodegradability of acrylic acid/sodiumpolymannuronate super-absorbent

    ZHANG Xiaohong;CUI Yingde;PAN Zhanchang

    2005, 56(6):  1134-1137. 
    Abstract ( 734 )   PDF (391KB) ( 1113 )  
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    A biodegradable super-absorbent was prepared from copolymer of acrylic acid(AA) with sodium polymannuronate(SPM). The effects of the amount of SPM and initiator, neutralization degree(Dn) of AA, reaction temperature(T) on absorbency and biodegradability of the copolymer were studied. When WSPM=1.5%,WKPS=0.15%,Dn=65%,T=70℃, the absorbency of the superabsorbent was 812 g•g-1 for pure water and 79 g•g-1 for normal saline.The super-absorbent could be degraded by soil and specific microbes, the degradation degree was up to 17.36% within 60 days.

    Microcapsule used for self-healing polymer material

    TIAN Wei;WANG Xinhou;PAN Qiang;MAO Zhiping

    2005, 56(6):  1138-1140. 
    Abstract ( 929 )   PDF (541KB) ( 341 )  
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    Microcapsules with dicyclopentadiene(DCPD) as core material and urea formaldehyde resin as wall material used for making self-healing polymer material were prepared with the in-situ polymerization method.The effect of microcapsules on the fracture toughness of epoxy resin was studied.The addition of microcapsules into epoxy resin results in the decrease of fracture toughness.When microcapsule content was kept constant,as the microcapsule size increased the fracture toughness of the epoxy resin decreased linearly and the percentage of decrease compared to the neat epoxy without microcapsules increased linearly.Moreover, the fracture toughness of the material decreases linearly with the increase of microcapsule content.
    Formation mechanism of MFI type zeolite membrane bytemplate-free secondary growth
    JIANG Haiyang, ZHANG Baoquan, LIN Yaosheng, LI Yongdan
    2005, 56(6):  1141-1143. 
    Abstract ( 730 )   PDF (620KB) ( 418 )  
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    Based on two template-free secondary growth methods, the formation mechanism of single-layer and multi-layer zeolite membranes was investigated. The composition of the synthesis solution did not affect the membrane structure, whereas the position-setting of the seeded support in the synthesis solution and the ageing process of the synthesis solution were two critical factors in the formation of the membrane. The synthesis solution with lower viscosity could easily penetrate into the gap between seeds boundaries, resulting in the formation of multi-layer membranes.
    Combined trapezoid spray tray and its hydromechanics
    LIU Jidong, LV Jianhua, ZHANG Jingping, LI Chunli
    2005, 56(6):  1144-1149. 
    Abstract ( 604 )   PDF (478KB) ( 414 )  
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    Combined trapezoid spray tray (CTST) is one of spray trays with special trapezoid structure. The plate has some advantages such as higher flux and efficiency, lower pressure drop, better blockage and foaming resistance.The hydromechanics of CTST was studied.The pressure in the cap was lower than that out of the cap in the zone of cap gap. Therefore CTST is favorable for liquid coming into the cap from the plate. Gas velocity distribution in the cap was studied, and there were two small eddy zones at the bottom of the cap. On the upside in the cap, gas velocity was high owing to the decrease of cross section area, which provided liquid with enough energy to be broken up and sprayed out of the cap. With the cap, gas (or vapor) was capable to lift liquid from the plate up to the space between plates where was the main space of mass transfer. Little liquid was stagnant when passing through the cap, which made liquid holdup small.
    现代化工技术

    Performance diagram analysis and its developments for distillation trays

    LIU Yansheng
    2005, 56(6):  1150-1155. 
    Abstract ( 796 )   PDF (666KB) ( 523 )  
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    Some new considerations and developments of the performance diagram of trays (PDT)were briefly described.Some new ideas of constructing PDT were put forward in which the operating limitations were based on hydraulic limitations and mass transfer restrictions. The former was a necessary condition for normal hydraulic operations inside distillation column,and the latter belonged to a sufficient condition for high mass transfer efficiency guaranteed. Thus, the effects of various limitations or restrictions of trays on the distillation column operations could be clearly defined and reliably determined.The method of the feasible & stable range(FSR) was presented for the case of frequent variations of feed conditions.The suitable X/Y coordinates of the PDT were also discussed.