Volumn Content

The Chinese Journal of Process Engineering 2002 Vol.2 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Catalytic Cracking of Bio-oil from Biomass Pyrolysis GUO Xiao-ya; YAN Yong-jie; LI Ting-chen; REN Zheng-wei; YUAN Chuan-min    2002, 2 (1): 0-0.   Abstract （1594）      PDF （199KB）（662）       Knowledge map    Save Tests indicate that the kinetics of leaching poorly-floated zinc–oxide–ore with ammonia comply with the shrinking un-reacted core model without solid product. By investigating the effects of ammonia concentration, temperature and size of ore on the leaching rate, it was suggested that the leaching of poorly-floated zinc-oxide-ore with ammonia is one of the first order reaction. Its activation energy is 11.1 kJ/mol, indicating that the external mass transfer was the rate controlling step. Related Articles | Metrics Select Preparation of Super-fine Spherical CaCO3 by the Carbonation Method XIANG Lan; XIANG Ying; YUAN Hong-xia; WANG Ting-jie    2002, 2 (1): 0-0.   Abstract （1612）      PDF （276KB）（732）       Knowledge map    Save The feasibility of preparing super-fine CaCO3 powder by an improved carbonation method was studied. The influence of gas distribution, chemical agents and CO2/N2 mixture on the size and morphology of CaCO3 was investigated. Bubbles with smaller size and gas mixture with higher CO2 concentration are favorable to the formation of super-fine CaCO3. The morphology and diameter of CaCO3 product are influenced obviously by the addition of additives such as ZnCl2, MgCl2 or EDTA . Related Articles | Metrics Select New Technology for Pd Recovery from Selectively Leached Residue of Waste Palladium Catalyst YANG Jian-wen;ZHONG Hai-yun;ZHAO Xuan;ZHONG Hui;LI Jian;DAI Yan-yang;MIAO Jian-li    2002, 2 (1): 0-0.   Abstract （2818）      PDF （279KB）（602）       Knowledge map    Save Amorphous composite powders are prepared by spray drying via nitrate solution precursors, and multiphase zirconia-based ceramics in the form of equiaxed grains are synthesized either by mean of direct sintering of the composite or by mean of sintering after pyrolysis and moulding. The effects of moulding pressure, sintering temperature, sintering period and dopants of Al3+ and Fe3+ on the structure of phases, the size and micrographs of grains are discussed. Related Articles | Metrics Select Asymmetric Conversion of 1-Phenyl-1,2-ethanediol by Candida parapsilosis SYB-1 NIE Yao; XU Yan    2002, 2 (1): 0-0.   Abstract （2484）      PDF （202KB）（668）       Knowledge map    Save Thermal cycle resistance of Al2O3/Ni-Ti/Kovar joints was studied, which were prepared by active brazing technique. The experimental results show that the joint shear strength increases after 200~600~200oC thermal cycles. The phenomenon is analyzed in view of the materials thermal expansion, solder microstructure and cycle temperature. The reason of strength increase is that the annealing effect in thermal cycles reduces the joining residual stress. Related Articles | Metrics Select Searching Information of Green Chemistry on Internet GUAN Yi; LI He; TIAN Jian; ZHANG Feng-bao    2002, 2 (1): 0-0.   Abstract （2289）      PDF （144KB）（689）       Knowledge map    Save Based on the experience of searching the information of green chemistry on Internet and the screening analysis of the searching results from different search engines, the main green chemistry institutions and organizations, some key academic journals, research institutions in universities, and patent search engines related to green chemistry all over the world on Internet are introduced. Moreover, the most effective search engines are recommended to readers. Related Articles | Metrics Select NOx-suppressed Smokeless Combustion Technique and Application in Coal-fired Kilns XU You-ning; SONG Wen-li; BAI Yun-ru; ZHANG Jian-guo; LIN Wei-gang; LI Jing-hai    2002, 2 (1): 0-0.   Abstract （2610）      PDF （88KB）（726）       Knowledge map    Save Superabsorbent resin as a new kind of functional polymer material has been extensively used in agriculture. In this paper, the mechanism of high water-absorbency, characteristics, categories and methods for uses of the polymer in agricultural application is introduced. The mechanism of soil improvement, drought relief and water saving, growth promoting as well as affecting factors on such functions are analyzed. The topics for research and future trend are discussed. Related Articles | Metrics Select Prediction of Solids Holdup Time Series of a Gas–Solid Circulating Fluidized Bed LI Xiao-xiang; SHI Yan-fu; HUANG Wei-xing; YU Hua-rui; ZHU Jing-xu    2002, 2 (1): 0-0.   Abstract （1550）      PDF （159KB）（629）       Knowledge map    Save Gas–liquid flow in bubble columns is studied by taking dispersed bubbles and liquid as co-existing continua. The mathematical models of gas hold-up distribution and the liquid circulation are developed under the assumptions that the gas phase is non-Newtonian and there is no frictional force between gas and liquid phases. The calculated results are coincident with experimental data satisfactorily. Related Articles | Metrics Select Physical Modeling of the Vortex Phenomenon in Continuous Casting Mould LEI Hong; ZHU Miao-yong; HE Ji-cheng    2002, 2 (1): 0-0.   Abstract （1427）      PDF （129KB）（605）       Knowledge map    Save The two-step leaching technique was used to extract silver from manganese-containing silver ore. In the first step the ore was leached with a binary ore process to resolve manganese oxide and expose the fresh silver ore, using pyrite as reductant. The manganese leaching reached 98% and the leaching conditions are: leaching temperature 95oC, leaching time 5 h, pyrite: manganese ore=0.28. When the ultrasonic wave at the rate of 40 kHz is applied to the reaction system, the leaching time can be reduced by 50% and the pyrite consumption amount is decreased by nearly 20%. Then, the leaching residue was treated to extract silver and the recovery was 95%. Related Articles | Metrics Select Characteristics and Active Energy for the Precursor of Lithium Manganese Oxides ZHAO Ming-shu; SONG Xiao-ping; ZHAI Yu-chun; TIAN Yan-wen    2002, 2 (1): 0-0.   Abstract （2588）      PDF （393KB）（591）       Knowledge map    Save The effect of ultrasonic wave on the crystallization of ammonium molybdate aqueous solution was studied. The crystalline and thermochemical property under ultrasonic effect were discussed. It is indicated that ultrasonic has a great effect on the reaction system of preparing b-type ammonium tetramolybdate. The crystallization time was shortened from 1~2 d to 10~20 min under ultrasonic and the crystalline form became microcrystal-type under ultrasonic. The total energy and condensation of atoms of H2Mo7O244– and [(MoO2)(MoO3)x–1]2+(x=1, 2, 3) were computed at the HF/ 3–21G, STO–3G level, and their geometrical structures were optimized using the molecular mechanics optimization method. The calculation results show that the reason of transformation from H2Mo7O244– to [(MoO2)(MoO3)x–1]2+ at pH 2.3~2.5 is the effect of ultrasonic. All ab initio calculations were performed with the Gaussian–98 program. Related Articles | Metrics Select Harvesting Spirulina Cells by Foam Flotation Technique on a Laboratory Scale ZENG Wen-lu; LI Hao-ran; LI Bao-hua; CONG Wei; CAI Zhao-ling; OUYANG Fan    2002, 2 (1): 0-0.   Abstract （1522）      PDF （138KB）（633）       Knowledge map    Save Taking Spirulina cells as the model, experiments were carried out on a novel and effective slant-armed bubble column to investigate the feasibility of foam flotation of micro-algal cells. The effects of a number of operation parameters such as carrying-gas flow rate, solution pH value, concentrations of ethanol and Tween 20 on the enrichment ratio and recovery of cells were examined and some useful data were presented. Related Articles | Metrics Select Alkylation Reaction of Thiophene with Olefins over Acid Catalyst of AlCl3 Supported Resins LUO Guo-hua; XU Xin; YANG Chun-yu TONG Ze-min; PENG Shao-yi    2002, 2 (1): 0-0.   Abstract （1432）      PDF （154KB）（624）       Knowledge map    Save A gold leaching process for an acid leached residue from an arsenic refractory gold concentrate in lime slurry under pressurized oxygen is investigated. The residue contains 17.4% of elemental sulfur. The experimental results show that the optimum quantity of lime added to the leaching solution should ensure the mole ratio of elemental sulfur to OH– in the range of 0.8 to 1.1. In 3 to 5 h, 90% of gold is leached at 85°C under 0.1 to 0.3 MPa oxygen pressure with the optimum lime addition in the solution. The thiosulphate produced from elemental sulfur in lime solution during oxygen leaching might be the major complexing agency for gold leaching. Related Articles | Metrics Select Influence of KCl Concentration on Chitin Deacetylation in Microwave Field YANG Zhen-qiu; SONG Bao-zhen; OUYANG Fan    2002, 2 (1): 0-0.   Abstract （2329）      PDF （219KB）（682）       Knowledge map    Save The liquid–liquid equilibrium data for two ternary systems, tetrahydrofuran–water–KF and tetrahydro- furan–water–K2CO3, at relatively high concentrations of salts, were measured at 25oC. The calculation of the liquid–liquid equilibrium were carried out using the Pitzer theory and the NRTL equations. The correlation and experimental data are found in good agreement. Related Articles | Metrics Select Preparation of Ultrafine Co Powder from Basic Co(OH)2 Slurry by Hydrogen Reduction YU Ke-ning; MAO Ming-hua; LIANG Huan-zhen; XU Ju    2002, 2 (1): 0-0.   Abstract （2565）      PDF （107KB）（637）       Knowledge map    Save The kinetic model of thrombolytic enzyme fermentation was studied in a 10 L auto-controlled bioreactor with Bacillus subtilis HL-986. Under the DO-stat batch culture condition, a set of unstructured kinetic models on biomass, reductant sugar consumption and thrombolytic enzyme production was proposed. Related Articles | Metrics Select Variable-mass Flow through the Vertical Perforated Channels XU Zhi-gang; YU Feng; LI Rui-jiang; WU Yong-qiang; ZHU Zi-bin; ZHANG Cheng-fang    2002, 2 (1): 0-0.   Abstract （1506）      PDF （251KB）（666）       Knowledge map    Save Silicon powder is an important raw material for direct synthesis of dimethyl-dichlorosilane in a fluidized bed reactor. It has wide size distribution and non-spherical shape, and it is necessary to investigate the silicon powder fluidization properties. A simple method has been proposed to predict the minimum fluidization velocity Umf from the pressure fluctuation of single and binary particle systems sieve-screened from silicon powders. The standard deviation of pressure fluctuations is found to increase linearly with the increase of the superficial gas velocity. Umf can be determined by extrapolation to the condition of zero standard deviation. Umf determined by the proposed method agrees well with that by the classical method from the pressure drop changes. Related Articles | Metrics Select The Source of Copper in Electrochemically Produced Cu2O and Its Elimination WANG Zhi-yong; CUI Shun; KANG Zhi-jun; LIU Ying    2002, 2 (1): 0-0.   Abstract （1392）      PDF （176KB）（590）       Knowledge map    Save To improve the quality of cuprous oxide produced by electrochemical reduction, the source, mechanism and elimination of metal copper in Cu2O is investigated. The metal copper in Cu2O came from the cathode reaction: Cu2O + H2O + 2e = 2Cu0 + 2OH–. K2Cr2O7 and diaphragm were used separately to decrease the content of Cu0 in Cu2O product, and significant improvement was resulted. Related Articles | Metrics Select Gas-stripping Fermentation Experiment Coupled with Carrier Gas Distillation for Ethanol Production QIN Qing-jun; JIA Hong-fei; WANG Yu-xin    2002, 2 (1): 0-0.   Abstract （1497）      PDF （139KB）（627）       Knowledge map    Save A new process for ethanol production is proposed in which gas stripping fermentation is coupled with carrier gas distillation. Fermentation usually needs to be operated at low temperature while distillation requires large amount of evaporation. The circulation of carbon dioxide meets both requirements and makes the coupling of fermentation with distillation possible. The feasibility of the proposed process was experimentally verified using an air-lift fermentor with a plate type distillation column on the top. Related Articles | Metrics Select Cathodic Reduction of Zn Complex Ion in the ZnCl2–NH4Cl Electrolyte MA Chun; YU Zhong-xing    2002, 2 (1): 0-0.   Abstract （1406）      PDF （248KB）（633）       Knowledge map    Save Related Articles | Metrics Select Electrochemical Behavior of Copper in HNO3 Aqueous Solution Containing BTA during CMP HE Han-wei; HU Yue-hua; HUANG Ke-long    2002, 2 (1): 0-0.   Abstract （2506）      PDF （144KB）（598）       Knowledge map    Save Influences of HNO3, H2O2 and BTA concentrations on filming of copper surface and CMP process were studied by electrochemical methods. Cu EIS in various media were examined. Relations of corrosion current density to polishing pressures and rotative rates were investigated. Changes of corrosion potential and polarization curves were explored. Electrochemical mechanisms of CMP were explained by changes of electrochemical variables such as corrosion potential and corrosion current density. The formula of 1% HNO3+1% BTA+0.2% H2O2+5% g-Al2O3 was confirmed to be feasible and reasonable. Related Articles | Metrics Select A MINLP Model of Eco-Industrial Parks CHEN Ding-jiang; LI You-run; SHEN Jing-zhu; HU Shan-ying    2002, 2 (1): 0-0.   Abstract （2563）      PDF （224KB）（640）       Knowledge map    Save The design and management of eco-industrial park (EIP) should be conducted based on quantitative analysis, for which the principles and methods are needed to be developed. By means of deterministic mathematical programming, a model for EIP decision is developed with an object oriented method in this paper. Logical proposition expressions are introduced into the model, so that the decision in the course of EIP design and management can be formulated as a mixed integer nonlinear programming (MINLP) problem. The model consists of two kinds of blocks: member models and connection models. These blocks form a modular architecture, by which EIP scenarios with different topological structure are represented. It is easy to expand, modify, reuse the EIP model, and can be used as the kernel model in EIP decision making. A case study of a prototype EIP in Zaozhuang City, China is illustrated. Three mass and energy integrated scenarios are studied. The MINLP model is solved by LINGO software. Related Articles | Metrics Select Pressure Drop Characteristics of Vertical Dilute-phase Gas Conveying JING Shan; JIANG Pan-liang; HU Qing-yuan; WANG Jin-fu; JIN Yong    2002, 2 (1): 0-0.   Abstract （1370）      PDF （170KB）（641）       Knowledge map    Save A novel separator for gas–solids co-current down-flow reactors patented by Kwauk et al. is studied. The influence of operating conditions (gas velocity and solid circulating rate) and the structure on separator efficiency is investigated in a f37 mm downer. The experimental results show that under gas velocity 1~5 m/s and solids circulating rate 20~90 kg/(m2.s), the separator efficiency is above 99%, and the pressure loss is below 500 Pa. Related Articles | Metrics Select Research on the Mass Transfer Capability of the Flat Jet Continuous Reactor YE Shu-feng; HUANG Ye; LI Jie; TIAN Xin-zhong; XIE Yu-sheng; JIN Shan-tong; HUANG Ze-ming; DING Yi    2002, 2 (2): 0-0.   Abstract （2554）      PDF （169KB）（633）       Knowledge map    Save A bench-scale reactor was set up following the designing principles of external circulating fluidized beds. The reactor was made up with a master bed(f40 mm, 660 mm high) and an auxiliary bed(f80 mm, 600 mm high). Synthetic and industrial dyeing wastewater were treated in the fluidized bed. Increasing hydraulic retention time can increase effluent CODcr removal efficiency as water retention time is less than 4 h, while CODcr removal efficiency keeps 80% as HRT longer than 4 h. The change in influent CODcr and the thickness of biofilm shows no obvious effect on the effluent CODcr removal efficiency in the range of operating conditions tested. Related Articles | Metrics Select Behavior of the Gas-granule Plug Flow along a Horizontal Pipeline GUO Yan; YI Jiang-lin; JIN Yong; YU Zhi-qing    2002, 2 (2): 0-0.   Abstract （1486）      PDF （89KB）（628）       Knowledge map    Save Related Articles | Metrics Select Bioleaching of Ni–Cu Sulfide with Acidophilic Thermophile Acidianus brierleyi ZHAO Yue-feng; FANG Zhao-heng    2002, 2 (2): 0-0.   Abstract （1589）      PDF （160KB）（555）       Knowledge map    Save Co-liquefaction of coal and sawdust was studied in the presence of hydrogen-donor solvent, tetralin. Coal samples were prepared through floatation of the Xinwen coal, followed by enrichment of maceral constituents. Sample I was rich in vitrinite and Sample II fusinite. Effects of reaction temperature, time and initial cold H2 pressure were studied on conversion, yield, especially oil yield, through comparison between these two samples. Because it is more difficult to be liquefied, Sample II, is greatly affected by changes in temperature and time. However, it is almost independent of change in initial cold H2 pressure, owing to the role of tetralin as hydrogen vehicle. Certain product(s) formed from thermolysis of sawdust can help hydrogenation of the intermediate (asphaltene and preasphaltene) in further forming oil products. Related Articles | Metrics Select Application of Stoichiometric Displacement Model for Retention to the Chromatographic Separation by Molecular Imprinting Polymer SUN Rui-feng; LUO Hui; SUI Hong-yan; SHEN Zhong-yao    2002, 2 (2): 0-0.   Abstract （1557）      PDF （157KB）（561）       Knowledge map    Save A new technology was developed to couple the anaerobic digestion of food wastes with production of polyhydroxyalkanoates (PHAs). Acetic, propionic, butyric and lactic acids were produced during food wastes anaerobic digestion and their concentrations reached 5.5, 1.8, 27.4 and 32.7 g/L, respectively under appropriate digestion conditions. The fermentative acids were transferred through a dialysis membrane to an air-lift reactor for PHA synthesis by Ralstonia eutropha. Dry cell concentration and PHA content reached 22.7 g/L and 72.6%, respectively. The obtained PHA was a copolymer of b-hydroxybutyrate (HB) and b-hydroxyvalerate (HV) with 2.8% (mole ratio) of HV units in polymer. Related Articles | Metrics Select Portable X-ray Photography of Solid Concentration in Gas–Solids Fluidized Beds— (II) Application and Deviation Analysis ZHANG Zhi-pan; LUO Guo-hua; WEI Fei; WANG Zhan-wen    2002, 2 (2): 0-0.   Abstract （1421）      PDF （115KB）（653）       Knowledge map    Save Tray efficiency of sieve tray in a gas–liquid–solid three system was studied in the laboratory. The experimental data of tray efficiency at different conditions were obtained. The results show that when the concentration of solid phase increases, tray efficiency first increases and then decreases. The experimental phenomena were interpreted and the method for estimating tray efficiency was verified by our data in three phase system. Related Articles | Metrics Select Complex Fertilizer Production from the Residue in Producing Furfural Using Straw: Study on the LIU Jun-feng;YI Ping-gui;SONG He-fu    2002, 2 (2): 0-0.   Abstract （1550）      PDF （262KB）（634）       Knowledge map    Save This paper reviews investigations on the high-density circulating fluidized beds, which are compared to those on the low-density circulating fluidized beds. The authors believe that the study on hydrodynamics and other fundamentals of high-density circulating fluidized beds, especially in high-density downer, has a great future. Some key topics about HDCFB which deserve urgent, intensive attention are suggested. Related Articles | Metrics Select Recurrence Formulae for Particle Size Distribution Calculation JIN Bo; WAN Ming-rui; MA Xing-hua    2002, 2 (2): 0-0.   Abstract （2476）      PDF （336KB）（678）       Knowledge map    Save The pseudomonas delafieldii strain R-8 and Rhodococcus erythropolis N1-36 were used to remove the sulfur from hydrogenated diesel oil. Both strains utilize the organic sulfur compounds from diesel oils with approximate activities. Surfactants can increase the desulfurization rate. When agitating rate was 250 r/min with Tween80 present, the strain can remove 72% of the organic sulfur from low sulfur diesel oil (S<300 mg/L) in 72 h. But when sulfur concentration was higher than 1000 mg/L, the sulfur removal rate of diesel oil by strain R-8 is very low. Related Articles | Metrics Select Kinetics of Mycelium-immobilized Packed Bed Continuous Resolution of DL-alanine WANG Yan; ZHANG Feng-bao; SONG Zheng-xiao; ZHANG Guo-liang; WANG Zheng; ZHAO Lin    2002, 2 (2): 0-0.   Abstract （1691）      PDF （198KB）（605）       Knowledge map    Save Based on the systematical study of continuous resolution of DL-alanine employing the immobilized Aspergillus oryzae cell, the kinetics of the enzymic reaction was determined. Furthermore, the method of Newton-Raphson was applied to the solution of one-dimension-steady-diffusion model of packed bed for continuous resolution of DL-alanine. The calculated results of the model, with the error less than 10%, were in good agreement with those of experiments. It was demonstrated that the model was reasonable and accurate. Related Articles | Metrics Select Photocatalytic Degradation of Methyl Orange with Titanium Dioxide Thin Films WU Zheng-huang    2002, 2 (2): 0-0.   Abstract （1501）      PDF （99KB）（1012）       Knowledge map    Save The photocatalytic degradation of methyl orange under UV-ray with titanium dioxide thin films was investigated in this work. The effects of substrate, air bubbling flow, adding Fe3+ and H2O2 in methyl orange solution were examined. Fairly good coating conditions for the photocatalytic degradation of methyl orange in aqueous solution were suggested. Related Articles | Metrics Select Plasmid Stability in High Cell Density Cultures of E.coli HB101(pBR322) YU Guo-ce; JIAO Rui-shen; WANG Ji-cheng; WANG Shu-qing    2002, 2 (2): 0-0.   Abstract （2512）      PDF （147KB）（714）       Knowledge map    Save The purification and recover processes of phytosterols from deoderizer distillates were studied by the estertification, crystallization and recrystallization technique. The experimental results showed that the purity of photosterols is more than 95% and the total recovery is more than 80%. Related Articles | Metrics Select Effects of Seed Crystals on Preparation of a-Al2O3 Ultrafines by Wet-chemical Methods XU Ke-jing    2002, 2 (2): 0-0.   Abstract （2738）      PDF （242KB）（556）       Knowledge map    Save The oxidation of coal in supercritical water was investigated by using O2 decomposed in situ from H2O2 as the oxidant. The results indicated that the sulfur and nitrogen contained in coal were gradually converted into SO42– and N2 respectively by oxidation in the supercritical water medium. The coal oxidation became faster with higher reaction temperature and higher concentration of H2O2. Related Articles | Metrics Select Performance of Extraction of Zn(II) with Sec-octylphenoxy Acetic Acid WANG Yan-zhi; HAN Shu-min; LI Qiu-rong;LI De-qian    2002, 2 (2): 0-0.   Abstract （1531）      PDF （117KB）（655）       Knowledge map    Save The extraction performance of Zn(II) from HCl medium with a new kind of carboxylic extractant, ammonized sec-octylphenoxy acetic (CA–12) and ammonization of the extractant have been studied. The influence of extraction temperature, initial concentration of extractant, etc. on the extraction is examined. The results show that the best conditions for ammonization of CA–12 with NH3.H2O are NaCl concentration of 1.0 mol/L in diluted NH3.H2O and ammonization ratio up to 80%. Distribution ratio D rises along with the decrease of equilibrium acidity and the increase of initial concentration of the extractant. The slope of lgD–pH curve is about 2. 0.01 mol/L Zn(II) is almost extracted completely from HCl medium under the condition of initial pH=6.0~6.5 and initial extractant concentration CHA>0.10 mol/L. The value of DH of the process was calculated to be 3.28 kJ/mol. Related Articles | Metrics Select Preparation of Sb-doped SnO2 Ultrafine Powder via Oxidative-coprecipitation WEI Zhi-xian; FAN Wen-hao; CHENG Zun-hua; ZHANG Jian-mei    2002, 2 (2): 0-0.   Abstract （2618）      PDF （235KB）（659）       Knowledge map    Save Preparation of ultrafine powder of SnO2 doped with antimony by the oxidative-coprecipitation method is reported. The product was characterized by DTA-TG, XRD and TEM. The results showed that the grain size of SnO2 increased with heat-treatment temperature, Sb being doped with Sb2O5, the normal SnO2 crystaline structure was kept the same, but the growth of SnO2 powder was retarded, doping with Sb2O5 can increase more significantly the conductivity of SnO2 ultrafine powder. Related Articles | Metrics Select Properties of Ionic liquids and Its Applications in Catalytic Reactions WANG Jun-feng; ZHANG Suo-jiang; CHEN Hui-ping; LI Xian; ZHANG Mi-lin    2002, 2 (2): 0-0.   Abstract （1587）      PDF （158KB）（571）       Knowledge map    Save Related Articles | Metrics Select Preparation of Monodisperse Silica Ultramicrons WANG Ling-lingl;FANG Xiao-longl;TANG Fang-qiong;YANG Chuan-fangl; LIU Hui-Zhoul    2002, 2 (2): 0-0.   Abstract （1535）      PDF （238KB）（835）       Knowledge map    Save The main factors that affect the leaching rate of potassium in potash feldspar were studied. It is shown that the best reaction conditions are reaction temperature of 890~950oC, size of potash feldspar ores below 0.208 mm, and the weight ratio of sodium chloride to potash feldspar ores being 1. The study showed that the leaching process is controlled by the internal ionic diffusion of Na+ and K+ in potash feldspar. The relations between diffusion coefficient and reaction temperature is expressed by the Arrhenius formula: Deff=D0exp(-–Ea/RT), with Ea = 81.42 kJ/mol, D0=0.324 mm2/h. Related Articles | Metrics Select Hydrothermal Modification of Mg(OH)2 Particles in NaOH Solution XIANG Lan; JIN Yong-cheng; JIN Yong    2002, 2 (2): 0-0.   Abstract （1456）      PDF （286KB）（580）       Knowledge map    Save In order to find the temperature range and initial reactant ratio for the maximum yield of acetylene, chemical thermodynamic equilibrium of heterogeneous multi-component C-H system was studied. All the thermodynamic equilibrium calculations are based on minimization of Gibbs free energy in the temperatures range from 500 K to 5000 K at intervals of 100 K. All species for which data are available in the JANAF Thermodynamic Tables are included in the C-H system. The Gibbs free energy minimization is expressed as a nonlinear optimization problem including equation and inequality constraints. The results show that it is irrational to consider the C-H system as homogeneous. Only the results from a heterogeneous system is realistic and reasonable and the best temperature range for acetylene formation is 3400~3800 K. Related Articles | Metrics Select Effect of Particle Size on Products from Flash Pyrolysis of Huolinhe Lignite in a Spouted-entrained Bed CUI Li-jie; YAO Jian-zhong; LIN Wei-gang    2002, 2 (2): 0-0.   Abstract （2312）      PDF （162KB）（603）       Knowledge map    Save Related Articles | Metrics Select Recovery of Gold from Gold-leaching Acidic Thiourea Solution by P507 Extraction and Na2SO3 Stripping ZHU Ping; GU Guo-bang; JIA Bao-qiong    2002, 2 (2): 0-0.   Abstract （1636）      PDF （114KB）（834）       Knowledge map    Save The performance using P507 to extract gold from gold-leaching acidic thiourea solution was investigated. Gold was extracted by P507 of 1.65 mol/L in kerosene under the conditions of H2SO4 concentration 0.335 mol/L, phase ratio 1:1 and time of contact 5 min. The percentage extraction in a single stage reached 99.80%. When 50 g/L Na2SO3 was used for stripping, the percentage stripping in one stage reached 82.45%, and gold was separated from iron by stripping operation. Related Articles | Metrics Select Investigation on Extraction of Penicillin by Aliphatic Alcohols WANG Bin; CHEN Ji; LIU Qing-fen; AN Zheng-tao; LIU Hui-zhou    2002, 2 (2): 0-0.   Abstract （2418）      PDF （166KB）（647）       Knowledge map    Save Selective synthesis of lignin peroxidase (LiP) and manganese peroxidase (MnP) by Phanerochaete chrysosporium in N-limited submerged cultures was studied under different physiological conditions. Whereas lignin peroxidase was detectable only in a narrow range of nitrogen source concentration (0.8~1.8 mmol/L), manganese peroxidase reached considerable levels over a broad range (0.4~2.0 mmol/L). In the absence of Mn2+, only lignin peroxidase was detectable, which was also found when the concentration of Mn2+ was in the range of 0.06~0.84 mmol/L. High level of manganese peroxidase was obtained at very low concentration of Mn2+, and almost kept constant with the increment of Mn2+, but was repressed obviously when the concentration of Mn2+ was beyond 3.36 mmol/L. Pure oxygen increased the activity of lignin peroxidase by 50%, but had no obvious effect on manganese peroxidase. Related Articles | Metrics Select Enzymatic Kinetics of Immobilized L-aminoacylase and Its Continuous Resolution of DL-methionine WANG Shu-hao; LI Xiao-feng; WU Yan-ling; SONG Zheng-xiao; MA Zhong-hai; YUAN Ying-jin    2002, 2 (3): 0-0.   Abstract （2611）      PDF （251KB）（542）       Knowledge map    Save In the first part of the article,a new algorithm for pruning network Dynamic Optimal Brain Damage(DOBD) is introduced. In this part, two cases and an industrial application are worked out to test the new algorithm. It is verified that the algorithm can obtain good generalization through deleting weight parameters with low sensitivities dynamically and get better result than the Marquardt algorithm or the cross-validation method. Although the initial construction of network may be different, the finial number of free weights pruned by the DOBD algorithm is similar and the number is just close to the optimal number of free weights.The algorithm is also helpful to design the optimal structure of network. Related Articles | Metrics page Page 1 of 3 Total 113 records First page Prev page Next page Last page