Please wait a minute...
Table of Content
25 January 2004, Volume 55 Issue 1
    CFD SIMULATION AND EXPERIMENTAL STUDY OFMULTICHANNEL FLOW ELECTROPHORESIS (Ⅱ)SIMULATION OF FLUID FLOW AND SCALEUP OF APPARATUS
    LUO Jian, HUANG Sheng, SHE Minggang, LIU Zheng
    2004, 55(1):  1-8. 
    Abstract ( 610 )   PDF (313KB) ( 214 )  
    Related Articles | Metrics
    This paper presents computational fluid dynamics (CFD) simulation of fluid flow and protein migration in multichannel flow electrophoresis (MFE). The simulation shows that natural convection created by Joule heat occurs along the direction of electric field and influences the apparent electrokinetic migration of protein. Furthermore, the factors affecting natural convection are examined. The scaling up of the MFE apparatus is attempted by extending the dimension along the flow direction. In this case, an identical fluid flow status could be obtained for MFE apparatus of different scales, as suggested by CFD simulation. The validity of this scaling up strategy is demonstrated by fairly good agreement between the theoretical prediction and the experimental results obtained in MFE apparatus of different scales.
    PREPARATION AND PROPERTIES OF COMPOSITETiO2MACROPOROUS COPOLYMER AND ITS APPLICATION FOR EXPANDED BED ADSORPTION (Ⅱ) EXPANSION CHARACTERISTICS,LIQUID MIXING ANDADSORPTION PERFORMANCE
    QIAN Jianhua, LEI Yinlin, LIU Zuozhen, YAO Shanjing, WU Xingyan
    2004, 55(1):  9-14. 
    Abstract ( 733 )   PDF (239KB) ( 215 )  
    Related Articles | Metrics
    In the first part of this paper, the GET composite copolymer with pendant epoxy groups were prepared. It was reacted with diethylamine, forming an anion-exchange chromatographic medium DEAE-GET. The effects of liquid viscosity, flow velocity on expansion characteristics and liquid mixing performance of DEAE-GET in expanded bed were studied. Its expansion characteristics in STREAMLINE 25 column were found to obey the Richardson-Zaki equation. The increase of liquid viscosity, flow velocity resulted in the increase of axial mixing coefficient. In the range of flow velocity 100—500 cm•h-1, the low value of axial mixing coefficient in expanded bed (10-6—10-5m2•s-1) indicated that the liquid flow through the expanded bed was close to a plug flow profile. The maximum static adsorption capacity for BSA was found to be 43.0 mg•ml-1.The breakthrough curves for BSA adsorption on DEAE-GET and STREAMLINE DEAE in packed bed and expanded bed were compared,showing for each adsorbent they were close to each other.The maximum adsorption capacities on DEAE-GET in packed bed and expanded bed were 28.0 mg•ml-1 and 26.2 mg•ml-1 respectively.
    传递现象
    FORCED CONVECTION CONDENSATION PRESSURE DROP OF HC290-OIL MIXTURES IN HORIZONTAL MICRO-FIN TUBE
    DONG Maolin;TONG Mingwei
    2004, 55(1):  15-18. 
    Abstract ( 548 )   PDF (153KB) ( 174 )  
    Related Articles | Metrics
    Forced convection condensation pressure drops were experimentally determined for a horizontal micro-fin tube (2 m length, 11.44 mm ID) with HC290-oil mixtures. The oil was Suniso 3GS, widely used in refrigerant systems. The oil concentrations ranged from 1.95% to 5.28%. The micro-fin tube is a internally enhanced tube, which has 60 fins with a height of 0.25 mm and 20° spiral angle. The condensation temperatures varied from 40 ℃ to 45 ℃ and the refrigerant mass flux varied from 40 kg•m-2•s-1 to 220 kg•m-2•s-1. The pressure drop on the test section (inlet vapor quality 1, outlet vapor quality 0.1—0.25) increased greatly as refrigerant mass flux was increased while oil concentration showed negligible effect on pressure drop. Meanwhile based on Kaushik and Azer correlation modification, a correlation suitable to the experimental data was obtained.
    HEAT-TRANSFER FILM COEFFICIENTS OUTSIDE TUBE OF FALLING FILM HORIZONTAL-TUBE EVAPORATOR
    XU Li;WANG Shichang;WANG Yuxin;LING Yi
    2004, 55(1):  19-24. 
    Abstract ( 708 )   PDF (232KB) ( 421 )  
    Related Articles | Metrics
    The film thickness distribution and average thickness outside a horizontal test tube were measured by using a film-thickness meter. The effects of liquid load, evaporation boiling point, evaporation temperature difference and tube diameter on film thickness, waving intensity and, as a result, the heat-transfer film coefficients outside the horizontal-tube were studied experimentally. Experiments of the heat-transfer coefficient of horizontal-tube evaporation were conducted with various operation parameters. Wave function G(δ+) for describing the wave characteristics of the film on the surface of horizontal-tube and dimensionless evaporation heat-transfer film coefficient h(α)+2 were specifically defined. Equations of evaporation heat-transfer coefficient were set up by regression of experimental data. Some literature models of evaporation heat-transfer coefficients do not give satisfactory results, because film waving is not considered in the models. This shortcoming is overcome in the present models. These results provide a basis for further developing high efficiency heat-transfer process and novel evaporators.
    FRACTAL EDDY BREAKDOWN MODEL OF MASS TRANSFER IN TURBULENCE FLOW
    LIU Daijun, ZHONG Benhe, ZHANG Yunxiang
    2004, 55(1):  25-31. 
    Abstract ( 626 )   PDF (297KB) ( 283 )  
    Related Articles | Metrics
    The transfer phenomena of turbulence flow in an agitated tank were studied. Though turbulence is a sort of chaos or confusion in the long-run on the whole, there exist self-similar ordered structures in a local micro region, where cascade fluid phenomena can be depicted by using the form of vortex transport of N-S equation. According to the cluster breakdown process of eddy and the characteristics of turbulence, as well as the influence on each other between the solid and vortex, the distribution of eddies could be found, and the average contact time in which the fluid sweeps the surface of the solid could be obtained. Considering the combination of eddy breakdown with fractal dimension and Higbie’s penetration theory, a new turbulence mass transfer model was established. As the result, a model was valid for fitting the transfer experiment data.
    ANALYSIS OF TWO-PHASE ANNULAR FLOW CONVECTIVEEVAPORATION IN HORIZONTAL MICROFIN-TUBE
    MA Hugen, CAI Zuhui, LI Meiling
    2004, 55(1):  32-36. 
    Abstract ( 641 )   PDF (216KB) ( 248 )  
    Related Articles | Metrics
    The performance of annular flow and heat transfer in horizontal microfin tubes was analyzed. A prediction model was established to calculate two-phase forced convective heat transfer coefficient of annular flow in horizontal microfin tubes, by considering the effect of disturbance and secondary flow in liquid film and using the velocity distribution of rough tube and similarity function. The comparison between calculated value and experimental data showed good agreement with each other.
    EFFECTS OF PREPARATION CONDITIONS ONNi/SiO2 CATALYST ACTIVITYIN m-DINITROBENZENE HYDROGENATION
    LIU Yingxin, CHEN Jixiang, ZHANG Jiyan
    2004, 55(1):  37-41. 
    Abstract ( 516 )   PDF (214KB) ( 261 )  
    Related Articles | Metrics
    The effects of calcination temperature and reduction temperature on the silica supported nickel catalyst, which were prepared by impregnation of silica with nickel nitrate solution, were investigated in the liquid-phase hydrogenation of m-dinitrobenzene to m-phenylenediamine. The nature of the catalysts was discussed based on the characterization results of nitrogen adsorption-desorption (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM) and temperature-programmed reduction (TPR). With increasing calcination temperature, the surface area of the catalyst decreased progressively, but the interaction between NiO and SiO2 became stronger. At the same time, the crystallite of nickel increased with the increase of calcination temperature. The optimal calcination temperature was 773 K, at which highly dispersed nickel species could be present. The reduction temperature also affected the properties of the catalyst. At a lower temperature, the catalyst could not be reduced completely, while an improperly high temperature would cause sintering of the catalyst. The catalyst reduced at 723 K showed higher catalytic activity and selectivity.
    CATALYTIC COMBUSTION OF HYDROGEN/AIR IN MICROCHANNEL REACTOR
    CAO Bin, CHEN Guangwen, YUAN Quan
    2004, 55(1):  42-47. 
    Abstract ( 995 )   PDF (245KB) ( 520 )  
    Related Articles | Metrics
    The catalytic combustion reaction of hydrogen/air mixture was studied in a microchannel reactor. The effects of operation conditions on reactor behavior were investigated in detail by using both mathematic modeling and experiment work. Explosive mixtures of hydrogen/air [3%(mol)—15%(mol)] were safely handled in this reactor. The results showed that catalytic combustion reaction can be operated at high space velocity, isothermal and kinetic controlled regimes. Under the conditions of inlet hydrogen concentration of 8%(mol),reaction temperature of 150 ℃,space velocity of 106 h-1,hydrogen conversion was still higher than 90%.
    KINETIC MODEL FOR PREPARING HYDROXY TERMINATEDPOLYDIMETHYLSILOXANE IN ONE-STEP PROCESS
    ZHOU An’an, WENG Zhixue, SHAN Guorong, HUANG Zhiming, PAN Zuren
    2004, 55(1):  48-53. 
    Abstract ( 667 )   PDF (255KB) ( 312 )  
    Related Articles | Metrics
    Hydroxy terminated polydimethylsiloxane (PDMS) is one of the important silicone products. In this paper, PDMS was synthesized in one-step process with cyclosiloxanes as monomer and a base as initiator when the reaction was under the conditions of high temperature, adding water and oxygen-off. The kinetics of the reaction was studied by Gel Permeation Chromatography (GPC). Furthermore, from the reaction conditions of one-step process, the chemical features of such one-step process could be expressed as anionic ring-opening polymerization of cyclosiloxanes under the influence of water. So based on the classical mechanism study on anionic ring-opening polymerization of cyclosiloxanes,the reaction mechanism of such one-step process was proposed, the kinetic model of the one-step process was derived. The change of the concentration of active centers with the progress of reaction was quantitatively obtained according to the kinetic model. There are three periods:sluggish period, increasing period, and constant period. The results described above were also verified by examining the complex structure of the reaction mixture with infrared spectroscopy(IR).
    EXTRACTION EQUILIBRIA BEHAVIOR OF MONOCARBOXYLIC ACIDS BY TRIOCTYLAMINE (Ⅰ) EXTRACTION EQUILIBRIA
    LI Zhenyu, QIN Wei, DAI Youyuan
    2004, 55(1):  54-58. 
    Abstract ( 748 )   PDF (219KB) ( 485 )  
    Related Articles | Metrics
    Extraction process based on chemical complexation is of higher capacity and selectivity for dilute polar organic solution. In this paper, phase equilibrium governing the reactive extraction of formic, acetic, propionic, butyric, valeric, monochloroacetic, dichloroacetic, trichloroacetic, glycolic, lactic and glyoxylic acids from aqueous solution into solutions of trioctyl amine (TOA) in the diluents, 1-octanol, chloroform, 4-methyl-2-pentanone (MiBK), n-hexane and tetrachloromethane were investigated. The results showed that the extractability depended on the hydrophobicity (lgP) of the acids and the acidity of the acids (pKa). The extractability depended on the lgP for the solutes with pKa close to each other,if otherwise depended on pKa of the acid depended on it increased with increasing lgP of the acid and decreasing pKa. Also, the extractability depends on diluent type and TOA concentration, and under the condition of TOA loading less than 1, the extractability in various diluents shows 1-octanol≥chloroform>MiBK>tetrachloromethane>n-hexane. The specific basicity of TOA is one of the most important parameters indicating extractant dependence on solvent directly.
    分离工程
    EXTRACTION EQUILIBRIA BEHAVIOR OF MONOCARBOXYLIC ACIDS BY TRIOCTYLAMINE (Ⅱ)APPARENT EXTRACTION EQUILIBRIUM CONSTANT AND CORRELATION
    LI Zhenyu;QIN Wei;DAI Youyuan
    2004, 55(1):  59-64. 
    Abstract ( 683 )   PDF (208KB) ( 298 )  
    Related Articles | Metrics
    Based on the extraction equilibrium behavior of formic, acetic, propionic, butyric, valeric, monochloroacetic, dichloroacetic, trichloroacetic, glycolic, glyoxylic and lactic acid in part (Ⅰ) of this paper, mathematical models describing extraction behavior of monocarboxylic acid with trioctylamine (TOA) was set up by using the mass action law, and the apparent extraction equilibrium constants, K11, K21K31 and K12 were obtained. The calculated TOA loading approached the experimental data. The extraction equilibrium behavior depended on the three physical properties of carboxylic acid or extractant, i.e. acid hydrophobicity, acid acidity and the specific basicity of TOA. The correlation of K11 with these three properties was obtained, and can be used to predict the K11 of acids.
    EXTRACTION EQUILIBRIA BEHAVIOR OF MONOCARBOXYLIC ACIDS BY TRIOCTYLAMINE (Ⅲ)QUANTITATIVE STRUCTURE-PROPERTY RELATIONSHIP OF APPARENT EXTRACTION EQUILIBRIUM CONSTANT
    WANG Min;QIN Wei;DAI Youyuan
    2004, 55(1):  65-68. 
    Abstract ( 619 )   PDF (174KB) ( 285 )  
    Related Articles | Metrics
    Quantitative Structure-Property Relationship (QSPR) is a useful method in predicting physical and chemical properties based on the molecular structure, which has already been used in many fields successfully. In this paper, molecular connectivity indices combined with electronic parameter σ* were used to develop QSPR models for hydrophobicity (lgP) and acidity (pKa) of 11 mono-carboxylic acids. The calculated values were of good consistency with the experimental values of lgP and pKa. Further, the apparent extraction equilibrium constant K11 was correlated with the above molecule structure parameters and the specific basicity of TOA based on the result of the second part of this paper, and 114 sets of experimental K11 approached the correlated data well.
    过程系统工程
    SHORTCUT CALCULATION WITHIN PARTITION METHOD OF REACTOR NETWORK SYNTHESIS

    ZHANG Zhishan;ZHAO Wen;ZHOU Chuanguang; YUAN Xigang

    2004, 55(1):  69-73. 
    Abstract ( 659 )   PDF (170KB) ( 337 )  
    Related Articles | Metrics
    For the complex reactions (steady state, isothermal,constant volume and one inflow), this paper extends the attainable region partition method of reactor network synthesis from the concentration space to the instantaneous selectivity (S)-unreacted fraction of key reactant (x) space and establishes the models of two reactor networks basic constituent elements (PFR and CSTR) for waste minimization according to the properties of two important curves (maximum selectivity curve: dS/dx=0; maximum yield curve: S=0) within the partition method of reactor network synthesis and applies them to the simulation of the optimal reactor networks structure obtained by the partition method for several Van de Vusse reaction examples. The computation results are consistent with those reported in the literatures, which indicates the proposed method is to some extent convenient and practical.
    DIFFUSION AND CUT-OFF CHARACTERISTICS OF SA/CS-CaCl2/PMCG MICROCAPSULES
    ZHANG Liyang, YAO Shanjing, GUAN Yixin
    2004, 55(1):  74-80. 
    Abstract ( 780 )   PDF (302KB) ( 207 )  
    Related Articles | Metrics
    By measuring diffusion behavior of PEG with various molecular mass in SA/CS-CaCl2/PMCG microcapsules, it was shown that molecular mass cut-off of the microcapsules membrane was about 2000. Meanwhile, diffusion of small solutes including glucose, lactose, ethanol and L-glutamic acid in three kinds of SA/CS-CaCl2/PMCG microcapsules were determined. The mixed diffusion coefficients Dm and diffusion coefficients in capsular membrane D1 were calculated by a diffusion model. The results showed that the mixed diffusion coefficients Dm increased at first and subsequently slightly decreased with increasing concentration of PMCG, whereas D1 increased continuously. D1Dm indicated that the main resistance in mass transfer was mainly on the capsular membrane.
    CONTINUOUS THREE-STAGE HOLLOW-FIBER MEMBRANE BIOREACTOR SYSTEM USED IN BIOCONVERSION OF ACRYLAMIDE
    SUN Xudong, SHI Yue, YU Huimin, SHEN Zhongyao
    2004, 55(1):  81-86. 
    Abstract ( 828 )   PDF (290KB) ( 173 )  
    Related Articles | Metrics
    Polysulfone hollow-fiber membrane was used and a continuous process of three-stage hollow-fiber membrane bioreactor system was designed for bio-convertion of acrylonitrile to acrylamide.On the basis of single stage membrane bioreactor,the feasibility of multiple-stage continuous process was discussed.At 20 ℃,the three-stage membrane bioreactor process steadily lasted over 80 h, the conversion of acrylonitrile was 99.9%, and the productivity was 25.3 g acrylamide•g cell-1•h-1. Comparing with the original batch reaction process,the productivity was enhanced by above 40%. With the hollow-fiber membrane, immobilized cells were replaced by free cells, and steady continuous process was achieved. This process has a favorable foreground in industrial application, which leads to continuous production of acylamide.
    QUANTUM CHEMISTRY STUDY ON MECHANISM OF CATALYTIC DESULFURIZATION OF THIOPHENE
    ZHENG Kewen, GAO Jinsen, XU Chunming
    2004, 55(1):  87-90. 
    Abstract ( 551 )   PDF (146KB) ( 214 )  
    Related Articles | Metrics
    The mechanism of catalytic desulfurization of thiophene on molecular sieve catalyst has investigated with quantum-chemistry by using the semi-empirical AM1 calculation method and the static theory. Reaction trends of catalytic desulfurization of thiophene were determined based on the reaction energy needed, which was obtained with the AM1 calculation results of thiophene and possible carbonium ions on transition state.It was validated that the hydrogen transfer reaction played an important role in the catalytic desulfurization process. While thiophene molecules were under the catalytic cracking conditions, their carbonium ions were very active and reacted easily with α-olefins from the paraffin cracking reaction. Further, the catalytic cracking desulfurization took place by hydrogen transfer reactions with paraffin molecules. The hydrogen transfer reactions were exothermic, so a reduced reaction temperature was in favor of the catalytic cracking desulfurization of thiophene.
    NUMERICAL SIMULATION OF PROTON EXCHANGE MEMBRANE FUEL CELL CATHODE WITH CONVENTIONAL FLOW FIELD(Ⅰ)MODEL DEVELOPMENT
    HU Jun, YI Baolian, HOU Zhongjun, LIU Weifeng, ZHANG Huamin
    2004, 55(1):  91-95. 
    Abstract ( 437 )   PDF (210KB) ( 522 )  
    Related Articles | Metrics
    A two dimensional mathematical model was developed for the cathode of proton exchange membrane fuel cell with conventional flow field operating with air. The continuity equation, Darcy’s equation for porous medium, conductive equation and the convection-diffusion equation for O2 and water vapor were used in the gas diffuser, and a coupled boundary condition given by Butler-Volmer equation was used at the cathode catalyst layer interface. The current density distribution in the diffuser, the concentration of O2 and water vapor in the diffusion layer, the local current density distribution at the catalyst layer interface were calculated. The mechanism of gas transport in the cathode gas diffuser, the characterization of gaseous species concentration distribution in the cathode of PEMFCs with conventional flow field were studied.
    0
    NUMERICAL SIMULATION OF PROTON EXCHANGE MEMBRANE FUEL CELL CATHODE WITH CONVENTIONAL FLOW FIELD(Ⅱ)ANALYSIS OF INFLUENCE ON PERFORMANCE OF PEMFCs
    HU Jun;YI Baolian;HOU Zhongjun;CAI Yinghua;ZHANG Huamin
    2004, 55(1):  96-100. 
    Abstract ( 610 )   PDF (205KB) ( 259 )  
    Related Articles | Metrics
    The effects of parameters on the performance of PEMFCs with conventional flow field operating with air were discussed, including diffusion factors, the geometric parameters of flow field, the resistance of electrode, the activity of catalyst and O2 concentration in the flow channels, with the mathematical model developed in part I. The limiting current density would increase with increasing oxygen effective diffusion coefficient and decreasing electrode thickness. The performance of PEMFCs would be promoted with increasing exchange current density of oxygen reduction reaction, decreasing resistance of electrode and optimizing geometric parameter of flow field. The uniformity of current density distribution could be improved by increasing catalyst loading along the gas flowing direction.
    能源和环境工程
    DYNAMIC SIMULATION OF SPACE SOLAR-DYNAMIC POWER SYSTEM
    WU Yuting;CHEN Renkun;REN Jianxun;LIANG Xingang;GUO Zengyuan
    2004, 55(1):  101-105. 
    Abstract ( 555 )   PDF (199KB) ( 164 )  
    Related Articles | Metrics
    The working process of the space solar-dynamic power system is a dynamic process and the periodical change of eclipse and illumination period will influence system peformance. In order to study the dynamic characteristics of the system, a dynamic model was proposed by using the lumping method and dynamic simulation of the space solar-dynamic power system with electrical output power of 10 kW was performed. The simulation results indicated that the variations of temperature of phase change material and electrical output power with time were very small when the phase change materials were in the state of two phases, but the variations became bigger when the phase-change materials were in the state of single phase. In order to obtain a steady electrical output power, phase change material must be in the state of two phase by choosing a proper concentrator area.
    KINETICS OF NYLON-1010 POLYCONDENSAION AT EARLIER STAGE
    WAN Lihua, WENG Zhixue, HUANG Zhiming, PAN Zuren
    2004, 55(1):  106-109. 
    Abstract ( 555 )   PDF (171KB) ( 251 )  
    Related Articles | Metrics
    The kinetics of nylon-1010 polycondensation at earlier stage in an open system was studied. The melt polycondensation process in an open system was feasible since the volatibility of 1,10-decanediamine was low enough in the process.The kinetics was characterized by the pesudo-nonreversible reaction of the second order. The activation energy was measured to be 82.7 kJ•mol-1.It was much faster in comparison with the polycondensation of nylon-66 in a closed system.
    GRAFTING KINETICS AND GRAFT POLYMERIZATION RATE MODEL OF SOLID PHASE GRAFTING OF ACRYLIC ACID ON POLYPROPYLENE
    ZHAN Xiaoli, YANG Xiaobo, CHEN Fengqiu
    2004, 55(1):  110-115. 
    Abstract ( 635 )   PDF (232KB) ( 288 )  
    Related Articles | Metrics
    Based on the assumption that single radical termination is the main way of termination reaction of radical solid phase graft polymerization, the graft polymerization mechanism and the graft polymerization rate model were proposed. The expression of grafting rate model is Rp,g=Aexp(-Ea/RT)[I][M]α.The rate of graft polymerization was found to depend on initiator and monomer concentration to the 1st and less than 1st order respectively, and the actual rate constant of graft polymerization was found to obey the Arrhenius law. The effects of graft polymerization temperature and the concentration of initiator and monomer on the initial rate of graft polymerization were investigated in experiments. The relationship between initial rate of graft polymerization and the factors mentioned above coincided with the grafting rate model quite well. The parameters of the model were obtained by the nonconstraint-nonlinear optimization method. The frequency factor was 6.868×109,the apparent active energy was 58.89 kJ•mol-1 and the exponential order of monomer concentration was 0.
    材料科学与工程

    PREPARATION FOR MONODISPERSE NANOSIZED STRONTIUM SULFATE

    LI Caihong;LIU Jinrong;ZHANG Yuezheng;YUAN Xigang

    2004, 55(1):  116-120. 
    Abstract ( 565 )   PDF (211KB) ( 243 )  
    Related Articles | Metrics
    Micromixing of reactant is the controlling step in the reaction precipitation process because chemical reaction of the formation of sparingly soluble materials is generally very fast, which would lead to uneven supersaturation distribution at the macro-level. This results in wider crystal size distribution. In order to eliminate the effect of micromixing on crystal size distribution, micromixing must be complete prior to nucleation and growth of crystal to acheve uniformity of supersaturation distribution. A new method for preparing monodispersed nanopowder is proposed. In this method, the effect of reactant micromixing on precipitation is effectively resolved in terms of the supersaturation metastable zone principle that there is a metastable zone for supersaturation and its width can be altered. The nanopowder of strontium sulfate was prepared by using this method. The morphology of crystal was observed and the particle size and particle size distribution were measured by TEM and multi-angle sub-micron particle size analyzer. The phase of matter and purity were characterized by X-ray powder diffraction. The result showed that particle size distribution of the nanopowder prepared with this method was very narrow and powder morphology was identical. In terms of the phenomenological level, the mechanism of the action of EDTA and alcohol in the reaction system was assumed.
    SYNTHESIS OF GAS SENSITIVE COMPLEX OF 2,2′-BIPYRIDINE-1,1′-DIOXIDE WITH Cu(Ⅱ)AND ITS APPLICATION
    FU Tiexiang, CAO Jun, TAO Jun
    2004, 55(1):  121-124. 
    Abstract ( 705 )   PDF (169KB) ( 140 )  
    Related Articles | Metrics
    A gas sensitive complex was synthesized by reaction of 2,2′-bipyridine-1,1′-dioxide with CuCl2 in dimethylfor-mamide. The elemental analysis, IR, UV and molar conductivity indicated the composition of the complex as[Cu5(bipy O2)6Cl8]Cl2.The sensitivity properties study indicated that the complex showed good sensitivity and selectivity to ammonia.When working voltage was 3 V, the output voltage of the sensor manufactured by the complex increased suddenly from 66 to 1756 mV with the increase of ammonia conentration in the range of 0.05—0.40 mmol•L-1. When working voltage was 2 V,the output voltage of the sensor showed two sudden increase in the ammonia conentration range of 0.10—0.40 mmol•L-1 and 0.40—0.60 mmol•L-1.The increment was 450 and 960 mV.The sensor could be used in ammonia leak
    -alarm and in production processes to control NH3.
    MEASUREMENT AND CORRELATION OF SOLUBILITY OF CAFFEINE IN WATER AND ETHANOL
    HAN Jiabin, WANG Jingkang
    2004, 55(1):  125-128. 
    Abstract ( 1432 )   PDF (152KB) ( 1265 )  
    Related Articles | Metrics
    The solubility of caffeine in water and ethanol at 0—50 ℃ was measured using the laser method. The results were regressed with an empirical equation and simplified EOS correlation. A 2-2-1 backpropagation (BP) artificial neural network (ANN) model was selected from many other models. The prediction of interpolation and extrapolation of the data was made with trained 2-2-1 BP ANN model. The result was satisfactory.
    传递现象
    EFFECT OF STRUCTURAL PARAMETER ON HEAT TRANSFER IN HEAT RECEIVER
    CUI Haiting;YUAN Xiugan;XING Yuming
    2004, 55(1):  129-133. 
    Abstract ( 545 )   PDF (201KB) ( 305 )  
    Related Articles | Metrics
    The heat receiver is a key part of Solar Dynamic Power System. The structural parameter affects the heat transfer of the heat receiver. The enthalpy method was used to calculate the three-dimensional phase change process of the heat exchange tube. The maximum canister temperature, average canister temperature, the receiver gas exit temperature and liquid PCM fraction in many kinds of length diameter ratio and aperture were calculated. The results showed that the output temperature of the gas from the working fluid tubes could meet the expected demand during the sunlight and eclipse period. The maximum temperature of the PCM container was within the safe range.
    多相流
    HYDRODYNAMIC BEHAVIOR OF LIQUID-SOLID MAGNETICALLY STABILIZED BEDS
    MENG Xiangkun;MU Xuhong;JIANG Yusheng;ZONG Baoning;Min Enze;LI Bixiang;ZHU Huaijin;CHEN Xibo;FU Songbao;ZHU Zehua
    2004, 55(1):  134-137. 
    Abstract ( 617 )   PDF (161KB) ( 274 )  
    Related Articles | Metrics
    The hydrodynamic characteristics of liquid-fluidized magnetically stabilized beds (MSB) with commercial amorphous nickel alloy catalyst (SRNA-4) as solid phase and water as liquid phase in a cold model experimental apparatus ofΦ140 mm were investigated. The influence of magnetic field intensity on bed structure, pressure drop, minimum fluidization velocity, transition velocity, and liquid holdup were investigated. Mathematical models for minimum fluidization velocity, transition velocity, liquid holdup were established respectively. The operating phase diagrams of liquid-fluidized MSB with SRNA-4 catalyst of two different sizes were obtained.
    PREPARATION OF SO2-4/TiO2-SiO2 COMPLEX CATALYSTS AND ITS PHOTOCATALYTIC PROPERTIES IN DEGRADATION OF PHENOL
    QU Jifang, FANG Li, WU Zhigang
    2004, 55(1):  138-142. 
    Abstract ( 682 )   PDF (208KB) ( 248 )  
    Related Articles | Metrics
    Ultra fine SO2-4/TiO2-SiO2 complex catalysts were synthesized by the one-step calcination method,which used titania sulfate and white carbon as raw materials and polyvinyl alcohol as dispersing agent. Catalysts are characterized by XRDIRTDA and BET. Different preparation factors were discussed.The catalysts consisting of SO2-43.4% and TiO2∶SiO2=1∶6 showed excellent reaction activity and stability for the photocatalytic degradation of phenol.Controlling calcination temperature and time (450 ℃,2 h) could avoid or diminish the formation of Ti-O-Si bond and obtain higher Vg and better dispersivity of TiO2 on the surface of SiO2.The kinetic study on photocatalytic degradation of phenol with the complex catalysts in a suspension system under 40 W UV-lamp showed that apparent rate constant k conformed to a zero-order kinetic model at initial concentration <100 mg&#8226;L-1 and increased with increasing pH value of phenol solution up to pH=12.When pH=10, k=3.32×10-1 mg&#8226;L-1&#8226;min-1. Solar photocatalytic experiment also gave good results.
    分离工程
    SIZE-DEPENDENT GROWTH RATE MODEL FOR DEXAMETHASONE SODIUM PHOSPHATE
    HAO Hongxun;WANG Jingkang
    2004, 55(1):  143-146. 
    Abstract ( 486 )   PDF (139KB) ( 136 )  
    Related Articles | Metrics
    The size-dependent growth of dexamethasone sodium phosphate was studied in a MSMPR crystallizer. The Bransom,CR,ASL,MJ2 and MJ3 size-dependent growth rate models were discussed in details. Using experimental steady state population density data of dexamethasone sodium phosphate, the parameters of five size-dependent growth rate models were determined by the non-linear least-squares method. By comparison of experimental population density data and linear growth rate data with those calculated from five size-dependent growth rate models, it was found that the MJ3 model was the best one for predicting the growth of dexamethasone sodium phosphate.
    MODELING DELAYED COKING PROCESS BY ADAPTIVE SUPPORT VECTOR MACHINE
    SONG Xiaofeng, YU Huanjun, CHEN Dezhao, HU Shangxu
    2004, 55(1):  147-150. 
    Abstract ( 469 )   PDF (174KB) ( 350 )  
    Related Articles | Metrics
    The performance of support vector regression estimation was studied. It is found that the insensitive factor ε, penalty factor, and the kernel function along with its parameter are the main factors affecting the performance of support vector regression estimation.It remains a critical unsolved problem to determine the parmaeters of SVM. Cross-validation methods are commonly used in practice to decide the parameters of SVM, but they are usually expensive in computing time. A novel adaptive support vector machine (A-SVM) was proposed to determine the optimal parameters adaptively. The algorithms for adaptively tuning parameters of SVM were worked out. A-SVM was successfully applied in modeling delayed coking process. Compared with RBFN-PLSR methods, A-SVM was superior in both fitting accuracy and prediction performance. The proposed algorithms in general may be used in modeling complex chemical processes.
    过程系统工程
    SYSTEM PERFORMANCE MONITORING AND REGION IDENTIFICATION BASED ON CHARACTERISTIC SUBSPACE
    GUO Ming;WANG Shuqing
    2004, 55(1):  151-154. 
    Abstract ( 609 )   PDF (169KB) ( 288 )  
    Related Articles | Metrics
    In the operation and control of chemical processes, automatic data logging systems generate large volumes of data. It is important for supervising daily operation how to make use of the valuable information about normal and abnormal operation, significant disturbance and changes in operational and control strategies. In this paper, principal component analysis(PCA)is clarified from the view of space, and every different subspace represents different operational mode and process performance. Based on that, the distance between two subspaces is calculated to evaluate the difference between them. The method is illustrated by a case study of a fluid catalytic cracking unit(FCCU) reactor-regenerator system.
    REGULATION OF GLUTAMINE SYNTHETASE IN GLUTAMINE PRODUCTION BY FERMENTATION OF Corynebacterium glutamicum WITH in-situ NITROGEN STARVATION AND GRADIENT FED NITROGEN
    LI Chun, LIU Yulei, CHEN Kuifa, YANG Yan, CAO Zhu’an
    2004, 55(1):  155-159. 
    Abstract ( 565 )   PDF (204KB) ( 286 )  
    Related Articles | Metrics
    The effects of uniform and gradient fed nitrogen on glutamine synthetase(GS),glutamate dehydrogenase(GDH)and glutamate synthase(GOGAT)were investigated in glutamine production by fermentation of Corynebacterium glutamicum NS611 after 3 h of in-situ nitrogen starvation. It was shown that the strain in the later growth phase entered naturally into in-situ nitrogen starvation by controlling the initial concentration of urea and the biomass was slightly decreased. The pH value reached 6.5 again in the culture system, which confirmed the beginning of nitrogen starvation in the culture system. After 3 h nitrogen starvation the activity of GS was increased over two folds and the time of high activity of GS persisted three folds longer in the gradient fed nitrogen system than that in the normal fed batch. The higher activity of GDH was also maintained. The glutamine production increased by 72% than the original technology of nitrogen starvation and the time of fermentation was shortened by above 12 h.
    MECHANISM STUDY OF EFFECTS OF ELECTRODE POLARITIES ON EHD ENHANCEMENT OF BOILING HEAT TRANSFER
    LIU Yongqi, LI Ruiyang, WANG Fagang, YU Hongling
    2004, 55(1):  160-162. 
    Abstract ( 731 )   PDF (109KB) ( 195 )  
    Related Articles | Metrics
    The effects of electrode polarities on EHD enhancement boiling heat transfer were investigated theoretically and experimentally based on the analysis of electric field distribution affected by superheat boundary layer and charge injection. The results showed that electric field distribution was changed by the charge induced by temperature gradients in the superheat boundary layer, but the change was independent of electrode polarities. However, when electric charge injection occurred, the electrode applied positive high voltage might generate different characteristics of charge injection from that generated by applied negative high voltage. If the electric field on the surface of heat transfer increased due to charge injection, the augmentation effects would increase. The experiments demonstrated that positive high voltage gave larger enhancement factors than negative high voltage. The experimental phenomena could be interpreted well on the basis of charge injection characteristics.
    能源和环境工程

    PRELIMINARY RESEARCH ON DECHLORINATION OF 2,4-DICHLOROPHENOL BY NANOSCALE Pd/Fe

    WEI Jianjun;XU Xinhua;LIU Yong;WANG Dahui
    2004, 55(1):  163-165. 
    Abstract ( 433 )   PDF (106KB) ( 143 )  
    Related Articles | Metrics

    PURIFICATION AND CONCENTRATION OF ACID COPPER ELECTROPLATING RINSEWATER BY CONTINUOUS ELECTRODEIONIZATION PROCESS

    GUAN Shan;WANG Jianyou;WANG Shichang
    2004, 55(1):  166-167. 
    Abstract ( 608 )   PDF (72KB) ( 302 )  
    Related Articles | Metrics
    CHEMOSELECTIVE PREPARATION OF CHLOROSULFONYL-CONTAINING AZO-DYES WITH THIONYL CHLORIDE-N,N-DIMETHYLFORMAMIDE
    TANG Lijun, ZHANG Shufen, CUI Zhihua, YANG Jinzong, GAO Wentao
    2004, 55(1):  168-170. 
    Abstract ( 548 )   PDF (114KB) ( 176 )  
    Related Articles | Metrics