Please wait a minute...
Table of Content
25 December 2003, Volume 54 Issue 12
    传递现象
    MEASUREMENT AND NUMERICAL SIMULATION OF FLOW FIELD IN STIRRED TANK WITH MULTIPLE IMPELLERS
    MA Qingshan;WANG Yingchen;SHI Litian;WANG Jiajun
    2003, 54(12):  1661-1666. 
    Abstract ( 684 )   PDF (241KB) ( 571 )  
    Related Articles | Metrics
    In this paper the commercial software package CFX-4 is used with k-ε model, RNG k-ε model, Low Reynolds Number k-ε model and algebraical stress model to simulate the flow generated by multiple impellers in a cylindrical baffled tank. The equations are discretised by the finite-volume approach. The mesh is divided into two parts which are fixed to their respective frames of reference, one being stationary and the other rotating with the impeller. At the interface between these two parts the rotating mesh slides over the fixed one at each time interval. The computation proceeds simultaneously over the whole flow field and the solutions in both rotating and stationery domains are coupled at all times.The simulation results show that the algebraical stress model predictions successfully reproduce the characteristics of flow, and are in good agreement with those obtained by LDV measurement. However the flow field simulated by k-ε model and RNG k-ε model is contorted by the underlayer impeller, and showes significant variation with experimental results.
    CFD SIMULATION AND EXPERIMENTAL STUDY OF MULTICHANNEL FLOW ELECTROPHORESIS(Ⅰ)ION DISTRIBUTION MODEL
    LUO Jian;ZHOU Jin;HUANG Sheng;LIU Zheng
    2003, 54(12):  1667-1673. 
    Abstract ( 616 )   PDF (258KB) ( 163 )  
    Related Articles | Metrics
    Application of computational fluid dynamics (CFD) to multichannel flow electrophoresis (MFE), a preparative electrophoresis process performed in a membrane spaced multicompartment electrolyzer, was attempted in order to simulate fluid flow in each compartment, which was fundamental in MFE process optimization and apparatus design. A mathematical model describing the distribution of pH and buffering ions along the flow direction in each compartment was established on the basis of mass transfer analysis and electrolysis equilibrium, as well as electric neutrality. The validity of the model was demonstrated by good agreement between the calculated data and the experimental results. The establishment of this model paves the way for the subsequent study of CFD simulation of MFE.
    CALCULATION OF TOTAL RADIATIVE EXCHANGE AREAS USING DISCRETE TRANSFER METHOD
    SHEN Jiubin, CHEN Haigeng, CHEN Wan
    2003, 54(12):  1674-1677. 
    Abstract ( 632 )   PDF (166KB) ( 500 )  
    Related Articles | Metrics
    Total radiative exchange areas are resolved inversely with the radiative transfer fluxes obtained by the discrete transfer method (DTM), which can be easily performed. The DTM using the dimensionality reduction method is used to calculate the total radiative exchange areas in a two-dimensional enclosure. Compared to the basic zone method, the method can decrease CPU time greatly with enough accuracy. The results also fully satisfy the reciprocity and integrality of total radiative exchange areas, which shows that DTM is a better method for calculating the total radiative exchange areas.
    THERMAL STRESS OF SLAG ON WALL TUBE CREATED BY BOILER LOAD SHIFT
    ZHOU Junhu, YANG Weijuan, LIU Jianzhong, ZHOU Zhijun, CAO Xinyu, CEN Kefa
    2003, 54(12):  1678-1682. 
    Abstract ( 676 )   PDF (208KB) ( 279 )  
    Related Articles | Metrics
    Spontaneous drop of slag on wall tube at the time of boiler load shift was studied theoretically. Slag thermal stress was assumed to be composed of slag shaping thermal stress and temperature gradient thermal stress.A model was established to calculate slag thermal stress. The distribution and quantity of slag thermal stress created by boiler load shift were calculated and analyzed. Thermal stress could be as great as E/1000 and be enough to destroy slag structure and to make some fall off.Wall tube parameters could only affect thermal stress of the slag which is 1mm near the contact surface and contribute little to slag fall-off.
    EFFICIENT MICROWAVE RADIATION REGENERATION OF POLYMERIC RESIN ADSORBING VOLATILE ORGANIC COMPOUND
    WANG Hongjuan, LI Zhong, XI Hongxia, FU Kan
    2003, 54(12):  1683-1688. 
    Abstract ( 820 )   PDF (257KB) ( 336 )  
    Related Articles | Metrics
    This paper is mainly concerned with regeneration of adsorption polymeric resin by microwave.The principle of regeneration of polymeric resin using microwave radiation was presented.Adsorption of ethanol on the resin and its desorption from the resin using microwave radiation were studied. Experiments of cocurrent desorption and countercurrent desorption of ethanol from the polymeric resin in a fixed bed using microwave radiation were conducted, and the corresponding elution curves of ethanol desorption and the temperature-rise curves of the fixed bed were respectively measured. Comparisons between the desorption elution curves obtained separately by using microwave radiation and direct heating were made. The desorption rate of ethanol by microwave radiation was higher than that by heating. The polymeric resin used in this work is semi-transparent to microwave and its ability to absorb microwave decreases with increase in temperature. Therefore, with temperature rise and desorption of adsorbate under microwave radiation, the ability of the fixed bed to absorb microwave gradually weakens and thus the final temperature of the fixed bed does not exceed 84℃. The use of microwave radiation to regenerate adsorption resin will be promising.
    MEASUREMENT AND CORRELATION OF DIFFUSION COEFFICIENTS FOR AMINO ACIDS IN AQUEOUS SOLUTIONS
    ZHAO Changwei, MA Peisheng, SONG Xiaoxi
    2003, 54(12):  1689-1695. 
    Abstract ( 802 )   PDF (227KB) ( 373 )  
    Related Articles | Metrics
    The diffusion coefficients of some amino acids in the aqueous solutions at 30℃ were determined by the metallic diaphragm cell method which is characterized by accuracy, promptness and convenience. The cell constant was determined by measuring the diffusion coefficient of KCl aqueous solutions at 25℃. The reliability of the experimental method was verified by the system of sucrose-water at 25℃ with known diffusion coefficient. Based on the integral diffusion coefficients, the relationships among differential diffusion coefficients,densities, viscosities and concentration were correlated. A semi-empirical model which had been proposed and verified by some known system was extended to correlate the diffusion coefficients of amino acids in the aqueous solutions.The fitting accuracy of this model is satisfactory.
    多相流
    CHARACTERIZATION OF FLOW REGIMES IN VIBRATED FLUIDIZED BED USING CHAOTIC ANALYSIS

    WANG Yi;WANG Tingjie;JIN Yong

    2003, 54(12):  1696-1701. 
    Abstract ( 737 )   PDF (262KB) ( 417 )  
    Related Articles | Metrics
    In a fluidized bed with a high static bed height of 800mm and an inner diameter of 90mm, axial pressure fluctuations are measured at different gas velocities in a vibrated fluidized bed (VFB) and a non-vibrated fluidized bed. The noises in the signals are filtered by wavelet transform. The characteristics of the pressure fluctuations in the VFB and the non-vibrated fluidized bed are analyzed by using chaotic theory. It is shown that the correlation dimension and Kolmogorov entropy can be used to characterize the fluidization state in the VFB. There is a jet regime near the air distributor of the VFB, in which the pressure fluctuations are chaotic. When gas velocity is near the minimum bubbling velocity, the correlation dimension and Kolmogorov entropy of the pressure fluctuations in the jet fluidization region reach the minimum. At lower or higher gas velocities, the values of the correlation dimension and Kolmogorov entropy are high due to the particles’ or bubbles’ random disturbance on pressure fluctuation. Above the jet fluidization region, the formation and coalition of bubbles are restrained due to the shear effect of vibration wave on the bed. The fluidization in the main part of the VFB is homogenous. In this region,pressure fluctuation is periodic. The correlation dimension is in the range of 1—1.5.Kolmogorov entropy approaches to zero.
    RESIDUA CHARACTERIZATION BY MODIFIED MOLECULAR CONNECTIVITY INDEX
    ZHENG Kewen, GAO Jinsen, XU Chunming
    2003, 54(12):  1702-1707. 
    Abstract ( 693 )   PDF (226KB) ( 117 )  
    Related Articles | Metrics
    Molecular structural characterization of the SCFE narrow-cuts of various residua was made by using molecular connectivity index (MCI) method in order to predict their physical properties and chemical reactivity. First-order MCI 1X was calculated for hundreds of SCFE narrow-cuts and correlated with their physical properties.The MCI 1X of SCFE narrow-cuts correlated very well with their physical properties for a given residue. The predicted physical properties of the SCFE narrow-cuts from various residua varied dramatically although they had the same MCI 1X.Apparently only the carbon atoms in the molecular skeletons are considered for calculating MCI. The existence of hydrogen atoms and their effects on the molecular structure and properties are neglected. Subsequently,the MCI was modified by integrating the atomic ratio of hydrogen to carbon (H/C) into the MCI to characterize the SCFE narrow-cuts of vacuum residua appropriately. A modified MCI KM was proposed by combining H/C and 1X. The quantitative structure property relation (QSPR) derived from the modified MCI KM and residue properties was developed to predict the physical properties and chemical reactivity appropriately. This MCI method was applied to the residue characterization successfully.
    过程系统工程
    OPTIMAL MULTI-PERIOD OPERATIONAL PLANNING FOR BOILER STEAM SYSTEMS
    YAN Liexiang;HU Shenghua;MA Dexian
    2003, 54(12):  1708-1712. 
    Abstract ( 682 )   PDF (171KB) ( 319 )  
    Related Articles | Metrics
    The multi-period operational planning for the boiler steam system was formulated as a mixed-integer nonlinear program (MINLP). The objective function accounted for both the operating costs for each period and changeover costs for start-up/shut-down of boilers between periods of operation. A sub-section method was proposed for solving the MINLP problem with the line-up competition algorithm (LCA) coupled with dynamic programming approach. The computation time for the method was proportional to the number of periods, and global solution of the MINLP was guaranteed. The effectiveness of the proposed method was illustrated with two examples.
    表面与界面工程
    EIS OF DUPLEX STAINLESS STEEL IN FLOWING CORROSIVE MEDIA
    YONG Xingyue;LIU Jingjun;LIN Yuzhen
    2003, 54(12):  1713-1718. 
    Abstract ( 817 )   PDF (236KB) ( 368 )  
    Related Articles | Metrics
    The electrochemical impedance spectroscopy(EIS)of duplex stainless steel in flowing chloride solution was measured. It was found that EIS of duplex stainless steel in flowing single phase media is a capacitive loop with a larger diameter when flow velocity is below the critical value, but EIS of duplex stainless steel is composed of two capacitive loops once flow velocity is above the critical value. If corrosive media contains solid particles, EIS of duplex stainless steel consists of a capacitive loop in high frequency range and a straight line in low frequency range when flow velocity is lower than critical value. However, an inductive component was observed on impedance plane and the shrinkage of the real part of impedance was also seen in low frequency range though EIS of duplex stainless steel is only a capacitive loop when flow velocity is higher than critical value. Electrode reaction kinetics model of duplex stainless steel in flowing chloride solution was found on the basis of electrochemical corrosion theory, which was used to explain EIS of duplex stainless steel in flowing chloride solution. The dominant role of electrochemical corrosion in the process of flow-induced corrosion of duplex stainless steel electrode in flowing chloride solution was further understood.
    生物化学工程、制药、食品和天然产物加工
    DYNAMIC FED-BATCH REFOLDING BEHAVIOR OF DENATURED-REDUCED LYSOZYME AT HIGH CONCENTRATIONS
    LI Lin;DONG Xiaoyan;SUN Yan
    2003, 54(12):  1719-1723. 
    Abstract ( 670 )   PDF (205KB) ( 191 )  
    Related Articles | Metrics
    Protein refolding process by fed-batch dilution is a course of protein dilution and refolding at the same time. In this work, the dynamic fed-batch refolding behavior of denatured-reduced lysozyme at concentrations up to 7mg•ml-1 was investigated to find the influence of some important factors, including the concentrations of denaturant (guanidine hydrochloride), lysozyme and redox reagents. The fed-batch refolding was operated by 60min fed-batch dilution and 24h incubation at 37℃. In the fed-batch process, the denatured-reduced protein could rapidly reach homogeneous distribution and be kept at low concentration in the refolding buffer, so the formation of protein aggregates was greatly suppressed. Thus, significantly higher refolding yield was obtained by the fed-batch dilution than direct dilution. With the increase of final lysozyme concentration, the fed-batch refolding yield decreased somewhat. However, this decrease could be alleviated by properly increasing guanidine hydrochloride concentration in the refolding buffer. In addition, at lysozyme concentrations higher than 3mg•ml-1, increased oxidizer concentration was needed to enhance the rate of intramolecular disulfide bond formation and thus the rate of protein refolding.
    CARBON SOURCE METABOLISM ANALYSIS FOR RECOMBINANT Pichia pastoris IN CHEMOSTAT BASED ON OXYGEN AND CARBON BALANCES
    GUO Meijin, CHU Ju, ZHUANG Yingping, HANG Haifeng, ZHANG Siliang
    2003, 54(12):  1724-1728. 
    Abstract ( 884 )   PDF (186KB) ( 630 )  
    Related Articles | Metrics
    Glycerol metabolism and methanol metabolism in genetically engineered Pichia pastoris were analyzed respectively in chemostat cultivation based on balances of oxygen and carbon elements.With the cell specific growth rate increasing from 0.064h-1 to 0.257h-1,the specific consumption rate of glycerol for cell growth metabolism increased from 1.36mmol•g-1•h-1 to 5.46mmol•g-1•h-1,whereas the percentage of glycerol metabolic flux for cell maintenance decreased from 14.4% to 4.0% when glycerol was the sole carbon source. The percentage of assimilation flux of glycerol increased by 5.9% while the percentage of catabolism flux of glycerol decreased by 5.9% , although the specific rates of assimilation and the specific rates of catabolism became larger.The recombinant human serum albumin was expressed in genetically engineered Pichia pastoris when methanol was used as substrate in continuous culture with specific growth rate increasing from 0.019h-1 to 0.046h-1.The largest specific consumption rate of methanol for target protein production was 0.31mmol•g-1•h-1,which was only 13.2% of all methanol metabolic flux at μ=0.027h-1.
    生物化学工程、制药、食品和天然产物加工
    EXTRACTION OF OFLOXACIN ENANTIOMERS WITH LIPOPHILIC L-TARTRATES
    TANG Kewen;ZHOU Chunshan
    2003, 54(12):  1729-1732. 
    Abstract ( 812 )   PDF (176KB) ( 483 )  
    Related Articles | Metrics
    The distribution behavior of ofloxacin enantiomers was examined in the aqueous and organic solvent of a two-phase system containing a chiral selector L-tartrate, and extraction equilibrium time and effect of pH , organic solvents and length of alkyl chain of L-tartrates on the partition coefficients and enantioselectivity of RS-ofloxacins, were investigated. The L-tartaric acid esters formed more stable complexes with R-ofloxacin than that with S-ofloxacin.The partition coefficients and enantioselectivity of RS-ofloxacins increased with increasing length of alkyl chain of L-tartrates.Solvents showed a large influence on enantioselectivity and partition coefficients.Optimum pH was about 7 for separation of RS-ofloxacins by extraction.
    能源和环境工程
    NEW DESIGN METHOD FOR EFFLUENT TREATMENT SYSTEM WITH SINGLE CONTAMINANT
    LI Baohong;FEI Weiyang;YAO Pingjing
    2003, 54(12):  1733-1739. 
    Abstract ( 528 )   PDF (247KB) ( 130 )  
    Related Articles | Metrics
    A new design method for effluent treatment system with a single contaminant is presented. The method consists of one principle and three rules. The key point of the method is that global optimality is obtained by guaranteeing the optimality of each step taken in the design procedure. The costs per unit mass of removed contaminant is used as a scale to choose the next combination of an effluent stream and a treatment process. The remaining problem is updated after each choice. After a primary distributed network without stream mix is obtained,the rules are used to further improve the structure.Comparing with the present targeting and mathematical programming methods, the new method is simple and effective.
    EFFECT OF GASIFYING AGENT MIXING RATIO ON POLYGENERATION SYSTEM GASIFIER PERFORMANCE
    ZHANG Jin;DUAN Yuanyuan;LI Zheng
    2003, 54(12):  1740-1744. 
    Abstract ( 681 )   PDF (203KB) ( 189 )  
    Related Articles | Metrics
    Polygeneration technology makes more reasonable use of energy to enable sustainable energy utilization. As opposed to separate chemical engineering and power generation systems, a polygeneration system demands more specific performance on the gasifier. The equilibrium working temperature of the gasifier and the composition of outlet syngas at this temperature were calculated by solving chemical equilibrium and energy equilibrium equations. The analysis was used to study the effect of gasifying agent mixing ratio on outlet syngas composition,cold gas efficiency, thermal efficiency and exergy efficiency. The optimum O2 coal ratio was found for a reasonable steam coal ratio(steam coal ratio had little effect on efficiency) for various kinds of coal to maximize thermal efficiency and exergy efficiency. These results can be used as a reference for optimization of polygeneration systems.
    材料科学与工程
    ULTRASONIC VULCANIZATION OF NATURAL RUBBER
    ZENG Haiquan;WEN Bangchun
    2003, 54(12):  1745-1749. 
    Abstract ( 777 )   PDF (196KB) ( 296 )  
    Related Articles | Metrics
    Conventionally rubbers are vulcanized in the presence of sulphur or peroxide at high temperature and pressure. This process has several significant shortcomings. In the present paper, natural rubber is vulcanized with the application of ultrasonic energy. The products of ultrasonic process exhibit the same properties as those that are vulcanized by using conventional process. However,the ultrasonic vulcanization process demonstrates many advantages over the traditional vulcanization methods such as high production rate, energy saving, uniform cure, etc. Energy generated due to phase difference between strain and stress,and sonochemical reaction within the compound are considered responsible for the vulcanization of rubber. The dynamic properties of unvulcanized natural rubber under ultrasonic frequency are obtained by means of the method of reduced variables of Ferry and Fitzgerald.Temperature rise curves at the beginning stage of the vulcanization are calculated from such properties.The calculated curves agree with the experimental results.
    PREPARATION OF CO2 FIXED CARRIER MEMBRANE BY PVP HYDROLYSATE AND ITS PERFORMANCE
    ZHANG Ying;WANG Zhi;WANG Jixiao;WANG Shichang
    2003, 54(12):  1750-1754. 
    Abstract ( 665 )   PDF (203KB) ( 349 )  
    Related Articles | Metrics
    Polyvinylpyrrolidone(PVP)was synthesized by the usual radical polymerization, and the composite membrane was prepared with PVP hydrolysate poly{N-vinyl-γ-sodium aminobutyrate}(PVSA) and polysulfone ultrafiltration membrane as its support. The structures of PVP and PVSA were investigated by infrared spectrum (IR) and X-ray diffraction (XRD).The permselectivities of the composite membrane for CO2/CH4 system were measured.The results show that at 26℃,1333Pa of gas pressure, the membrane displays a CO2 permeation rate of 5.46×10-7 cm3(STP)•cm-2•s-1•Pa-1 and CO2/CH4 ideal selectivity of 212.1. With increasing pressure in feed gas, both CO2 permeation rate and selectivity of CO2/CH4 decrease. The facilitated transport mechanism of CO2 in membrane was analyzed according to the characteristics of permeation flux vs pressure and the infrared spectra of the membranes in different states.
    传递现象
    MODEL FOR PREDICTING ROTATING STREAM TRAY EFFICIENCY
    CHEN Jianmeng;TAN Tian’en;SHI Xiaonong
    2003, 54(12):  1755-1760. 
    Abstract ( 741 )   PDF (212KB) ( 244 )  
    Related Articles | Metrics
    Based on the results of gas flow field,droplet size distribution and droplet initial flow rate distribution on a 300mm rotating stream tray (RST), a three dimensional droplet projection trajectory model and a mass transfer efficiency model were developed.The calculation of the models was carried out by using a finite-difference procedure. The predicted results of the plate efficiency agreed quite well with the experimental data measured with absorbing NH3 or SO2 on a 300mm RST and the operation data from a commercial 3600mm RST column. Meanwhile, the effect of gas-liquid system and RST’s structure on plate efficiency was discussed.
    SIMULATION OF TRICKLE-BED REACTOR FOR HYDROGENATION OF 2-ETHYLANTHRAQUINONE WITH PALLADIUM CATALYST
    LV Shuxiang, WANG Li, LIU Jianguo, CHEN Sihai, WANG Yaquan, MI Zhentao
    2003, 54(12):  1761-1765. 
    Abstract ( 847 )   PDF (198KB) ( 311 )  
    Related Articles | Metrics
    Hydrogenation of 2-ethylanthraquinone is a key step in the industrial production of hydrogen peroxide via anthraquinone. This reaction on palladium-supported catalysts is normally carried out in trickle-bed reactors. A numerical model for simulation of a gas-liquid-solid hydrogenation trickle-bed reactor is presented. The model is based on the film theory and takes into account the axial dispersion effect on the performance of the reactor. Comparison of calculated values with data from pilot plant and industrial reactor shows that the agreement is quite satisfactory and the maximum variance is less than 5%. Gas-liquid and liquid-solid mass-transfer coefficients are determined by semi-empirical correlations available in the literature. The palladium-supported catalyst is extremely active and the reaction is always controlled by gas-liquid mass-transfer, and the overall effectiveness factor is always very low in agreement with the high catalytic activity of the palladium-supported catalyst. The overall effectiveness factor increases with decreasing catalyst hold-up. Therefore, it is feasible to improve the productivity of unit catalyst by decreasing the catalyst hold-up in a commercial plant with the hydrodynamic characters kept unchange.
    分离工程
    CRYSTAL GROWTH KINETICS FROM AQUEOUS SOLUTION OF POTASSIUM SULFATE

    CHEN Yong;SHAO Manjun;CHEN Huiping

    2003, 54(12):  1766-1769. 
    Abstract ( 599 )   PDF (159KB) ( 392 )  
    Related Articles | Metrics
    The single crystal growth rates of potassium sulfate in pure aqueous solution under different conditions were determined by photomicrography in a flow system for crystal growth. The effects of the main controlling factors, such as supersaturation, crystal size, solution velocity and crystal growth temperature, on crystal growth rates of potassium sulfate were discussed in detail by using non-linear regression from the experimental data, and several empirical relationships were given.The results showed that the growth rates of crystals increased with supersaturation, crystal size, solution velocity and temperature. Moreover supersaturation was the most important controlling factor influencing growth rates of crystals,crystal size and solution velocity were the secondary and temperature was the least. Furthermore, It was found that the growth rate of crystals along the [100] crystallographic axis was higher than that along the [001] in the same condition. The effect of every factor on crystal growth rates along the [100] crystallographic axis was stronger than that along the [001].
    过程系统工程
    DEVELOPING DYNAMIC SOFT SENSORS USING MULTIPLE NEURAL NETWORKS
    LUO Jianxu;SHAO Huihe
    2003, 54(12):  1770-1773. 
    Abstract ( 526 )   PDF (149KB) ( 299 )  
    Related Articles | Metrics
    Since in practical industrial applications, soft sensors based on static models often lead to low accuracy and poor robustness, a multiple neural network (MNN) model is presented to develop dynamic soft sensors. The approach is applied to building a dynamic soft sensor estimating the production component in a simulated binary distillation unit and good results are obtained.
    能源和环境工程
    PURIFYING WASTE GAS CONTAINING LOW CONCENTRATION TOLUENE IN TRICKLING BIOFILTER WITH CERAMIC SPHERES

    LIAO Qiang;TIAN Xin;ZHU Xun;WANG Yongzhong;CHEN Rong;LIAO Hao

    2003, 54(12):  1774-1778. 
    Abstract ( 658 )   PDF (219KB) ( 446 )  
    Related Articles | Metrics
    The Purification experiments of waste gas containing low concentration toluene were made in trickling biofilter with ceramic spheres.The effects of liquid flow rate, gas flow rate, pH of circulation liquid, and toluene concentration in inlet gas on the purification efficiency of trickling biofilter were investigated.The pressure drop of the trickling biofilter was also measured during experiments. Increasing liquid flow rate and gas flow rate resulted in the decrease of purification efficiency of trickling biofilter.The highest purification efficiency of trickling biofilter was found at the circulation liquid pH of 7.The porosity of the packing material at the inlet of gas was higher than that at the outlet of gas in biofilter after continuous operation in 50 days. The decrease in the porosity of packing material caused a great increase in the pressure drop of the biofilter.
    材料科学与工程
    PREPARATION OF NANO TiO2 ON SURFACE OF SILICA
    WANG Ting;JIANG Xin
    2003, 54(12):  1779-1782. 
    Abstract ( 612 )   PDF (163KB) ( 287 )  
    Related Articles | Metrics
    TiO2 nanoparticles were in-situ prepared on the solid/liquid interfacial adsorption layer. In the suspension of colloidal silica particles in binary mixtures of water/ethanol, a water-rich layer was formed on the hydrophilic surface of SiO2. After phase equilibrium, dropping tetrabutyl titanate diffused into the adsorption layer and reacted with water. After centrifugation and drying, samples were obtained. The solvent-substituted experiment testified that reaction took place on the adsorption layer. TEM, XRD and electronic energy spectrum indicated uniform TiO2 laid over the surface of SiO2 particles. The effect of reaction temperature was investigated and potential mechanism was discussed.
    DIRECT PREPARATION OF HIGH PURE γ-ALUMINA FROM SODIUM ALUMINATE
    GAO Jianfeng, XU Chunyan, WANG Jianzhong, WANG Jiufen, ZHUANG Yuanyi
    2003, 54(12):  1783-1786. 
    Abstract ( 963 )   PDF (169KB) ( 903 )  
    Related Articles | Metrics
    The purification of mother liquor containing sodium aluminate by using desilication agent and the preparation of high pure pseudo-boehmite and gamma alumina are reported. The sodium aluminate in the mother liquor coming from Shanxi Aluminium Plant is treated with home-made desilication agent, the ratios of SiO2/Al2O3 and Fe2O3/Al2O3 in treated-solution are below 0.01%. The pseudo-boehmite is obtained with buffer solution deposition in which ammonia gas acts as a circulating medium. The specific surface area of pseudo-boehime powder reaches up to 300m2•g-1 and pore volume reaches about 0.7ml•g-1.The content of sodium in pseudo-boehime is below 0.005% after treating the pseudo-boehime with a sodium removal agent.The quality of this product is comparable to the SB powder made in Germany.Gamma alumina with a larger specific surface area and pore volume is obtained by temperature programmed calcination of pseudo-boehmite.
    材料科学与工程

    IMPROVEMENT ON SYNTHESIZING NIPAAm AND ITS APPLICATION

    SONG Jiangli;WANG Xiufen
    2003, 54(12):  1787-1789. 
    Abstract ( 579 )   PDF (121KB) ( 219 )  
    Related Articles | Metrics
    NIPAAm is a monomer which can synthesize intelligent polymers sensitive to environment. The method of synthesizing isopropylacrylamide is improved. The synthesis is noted for its simplicity, low toxicity, high yield and reproduction as compared with other methods. The melt point, boiling point, IR and NMR spectra of the compound were determined and compared with standard data and spectra for characterization. Further,linear p(NIPAAm) and p(NIPAAm) hydrogel were synthesized by using the NIPAAm and their temperature-sensitivity were investigated.
    BEST FIBER CAPACITY OF COMPOUNDED PLANT FIBER MATERIAL
    MIAO Zonghua, HUANG Zutai, LI Zhenghong, CHEN Lihui, QIU Renhui
    2003, 54(12):  1790-1793. 
    Abstract ( 1010 )   PDF (141KB) ( 152 )  
    Related Articles | Metrics
    The best capacity of fiber for different plant fiber composites and property index were obtained from experiment,and the best capacity of fiber corresponding to a single property index can be confirmed by the parabola equation. Furthermore, by combined the method of main composition analysis with the parabola equation, the best capacity of fiber can be determined accurately and reasonably which will provide the theorical basis and calculating method for determining the best capacity of plant fiber composites. The calculated optimum fibre contents of plant fibre composites are as follow:nylon matrix treated with coupling reaction 23.52%,nylon matrix treated with grafting reaction 23.77%,polypropylene matrix treated with coupling reaction 34.32%,polypropylene matrix treated with grafting reaction 27.71%.