Table of Content

20 June 2003, Volume 3 Issue 3

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3

Kinetics of Chemically Plating Nickel on the Surface of Hexagonal Boron Nitride Micro-particles

LI Fan; ZHAO Xiao-feng; ZHANG Deng-jun; LI Bao-hou; LUO Shi-min

. 2003, 3(3):  0-0. 

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The effect of inorganic salt added into aqueous fucoidan solution on fucoidan extraction was investigated. It is found that extraction of fucoidan decreases rapidly with the increase of inorganic salt concentration in the aqueous solution. Based on this phenomenon, the stripping of fucoidan was carried out with aqueous salt solution. The experimental results show that the stripping of fucoidan increases with the concentration of inorganic salt in the aqueous solution and decreases with the increase of fucoidan concentration in the organic phase. In addition, the stripping efficiency of NaCl solution is higher than that of CaCl2 solution at the same chloride ion concentration. The effect of organic solvent as diluent on the stripping of fucoidan was also studied. It is shown that the stripping of fucoidan with carbon tetrachloride as diluent is more difficult than that with the other organic solvents.

Preparation of Zeolite NaA Membrane on Rough Porous a-Al2O3 Tube

LIANG Yu-xiu; LU Jin-ming; LI Bang-min; WANG Jin-qu; YIN De-hong

. 2003, 3(3):  0-0. 

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Thiobacillus ferrooxidans are used to leach Ni from nicopyrite.It is found that better leaching is resulted when adapted bacteria are used in contrast to unadapted bacteria. Three factors inhibit adapted and unadapted bacteria in slurry: the concentration of Ni2+ and Cu2+, the presence of sulfide, and the shearing stress. The shearing stress seems to be the most important.

Kinetics on Chlorinating Rare Earth of Weishan Mid-grade Bastnasite in Shandong after Fixed Fluorine Treatment

SHI Wen-zhong; ZHU Guo-cai

. 2003, 3(3):  0-0. 

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The kinetics curved lines of chlorinating rate on chlorinating rare earth of Weishan mid-grade bastnasite in Shandong after fixed fluorine were determined. It is shown that the chlorinating process for fluorine-fixed calcine agreed well with the regional reaction rate model presented by Bagdasarym. The process consisted of two tandem steps, Erofeev Equation ln[–ln(1–a)]=lnk+nlnt was used to deal with the equation of reaction rate，the function between rate constant and temperature was k=2.7×107e–125900/RT. The apparent activation energy Ea was 125.9 kJ/mol. The process was mainly controlled by the interfacial chemical reaction.

Composition and Distribution of Naphthenic Acids in Crude Oil of High Acid Value

REN Xiao-guang; SONG Yong-ji; REN Shao-mei; QI Liang

. 2003, 3(3):  0-0. 

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At the high current density of 7.5~20 A/dm2 for chromium electrowinning, the polarization curves of hydrogen evolution on a chromium electrode at the conditions of 30~55oC and pH=2.1~2.5 were obtained to explore the electrochemical process of hydrogen evolution at high current density. It was found that the potential of hydrogen evolution decreases with the increase of temperature and decrease of pH. The polarization curves are shifted toward more negative when adding (CH3)3NC16H33Br (CTMAB) in the sulfate solution. It is shown that the CTMAB can suppress hydrogen evolution moderately. When electrowinning chromium in the solution with 20 mg/L CTMAB, the current efficiency is increased by 8.1%. A series of data of over-potential on the chromium electrode at different temperatures with pH=2.1 was obtained. All the Tafle plots at different temperatures pass through a common point with the coordinate lgi equal to 1.72 and over-potential to 1.35 V.

Process Engineering and Ecological Industry

JIN Yong; LIU Zheng; LI You-run

. 2003, 3(3):  0-0. 

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Great contribution to the human society was made by the process industry in the past century, which, however, also resulted in serious environmental problems, hindering the sustainable development of human society. The future development of process industry should be based on a renewed infrastructure, i.e., eco-industry, in which a product-chain or product-network will be developed by incorporation of resource utilization, energy consumption and pollution control, as can be found in native ecology. Multidisciplinary research will be an essential and effective way to the development of process engineering and industry.

Synergistic Extraction of Lanthanide Ions with 1,4–Bis (1￠–Phenyl–3￠–Methyl– 5￠–Pyrazolone–4￠–yl)–Butanedione–[1,4] and Diantipyryl Methane

ZHANG An-yun; YANG Zi-chao

. 2003, 3(3):  0-0. 

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The principle of electrical power generation is applied to FeCl3 leaching of synthetic PbS in this study. The dual cell technique and Evans diagram were introduced to examine the factors that influenced the electrogenerative leaching, such as composition of PbS electrode, agitation, temperature, FeCl3 and NaCl concentrations. It is confirmed that certain quantity of electrical energy in addition to the leached products can simultaneously acquired in the electrogenerative leaching process. The internal resistance of the electrogenerative leaching system is the key factor to power output and temperature affects the output of electrogenerative leaching. The apparent activation energy is determined as 18.26 kJ/mol for FeCl3 leaching of synthetic PbS. Higher FeCl3 and NaCl concentrations affect the electrogenerative leaching process favorably.

Preliminary Exploration of Degradable Crude Cellulose Resin

WEN Zhang-jun; QIAN Sheng-qiu

. 2003, 3(3):  0-0. 

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Desulfurization of high temperature coke oven gas (COG) by mixing zinc-bearing dust into coking coal has been studied. For simplicity, a mixture of pure powered iron oxide and zinc oxide were used in the experiment to simulate the dust. Thermodynamic calculation and desulfurization experimental results show that in the plastic stage when metaphase is formed, the zinc-bearing dust additive could suppress the evolution of H2S into COG efficiently and in the subsequent contraction stage when coke is formed, zinc sulfide is decomposed to elemental zinc vapor and H2S because of high H2 atmosphere in COG. The elemental zinc vapor reacts homogeneously with H2S to form solid ZnS as COG leaves the carbonization room. Thus the concentration of H2S in COG does not increase and little zinc is left in the coke. Experimental results also disclose that iron oxide in the additive has the effect to retard the release of sulfur into COG and promote zinc to evolve from coke as zinc vapor in the contraction stage.

Synthesis of Potassium Titanate Whiskers by Microwave Heating

YU Gang; LIU Chang; YANG Zhu-hong; FENG Xin; LU Xiao-hua

. 2003, 3(3):  0-0. 

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A method for synthesizing potassium titanate whiskers by microwave heating is described in this paper. A series of potassium titanium whiskers (K2Ti2O5, K2Ti4O9, K2Ti6O13) with diameter in the range of microns were obtained. Potassium carbonate and hydrous titanium oxide are used as starting materials. CuO and Fe3O4 are used as heating medium in order to induce the temperature. The effect of the experimental conditions including the ratio of starting materials, heating medium and irradiating time on the structure and morphology of the products were investigated. It was proved that the growth of whisker under microwave heating could be modeled with a “liquid melt inducing” mechanism.

Light Transfer and Its Effect on Cell Growth in the Culture of Transgenic Synechococcus sp. PCC7942

ZHU Du; LI Yuan-guang; YE Qin; WEI Xiao-dong; ZHANG Jun

. 2003, 3(3):  0-0. 

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A gold leaching process by using in situ oxidation products of added elemental sulfur in Ca(OH)2 solution was investigated. A gold concentrate containing 45 g/t Au was tested and 85%~87% of gold were leached. The leached gold depends mainly on the initial molar ratio of elemental sulfur to the hydroxyl ion, the consumption of oxygen and the reaction temperature. Adding some surfactants, such as lignosulfonic calcium, at lower concentration increased the leached Au but at higher concentration decreased it. Both of thermodynamic analysis and experimental results show that thiosulfate is the major complexing agent for gold in the process.

Hydrolysis of Olive Oil with Immobilized Lipase in a Tapered Column Reactor

YANG Bo-lun (杨伯伦);ZHAO Guo-sheng(赵国胜);LIN Hong-ye(林宏业)

. 2003, 3(3):  0-0. 

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Extensive experimental work on hysteresis in a cocurrent gas–liquid upflow packed bed was carried out with three kinds of packings and the air–water system. However, only when packed with small glass beads (f1.4 mm) was the bed pressure drop hysteresis observed. Two more liquids with different liquid properties were employed to further examine the influence of parameters on pressure drop hysteresis. The similarity of pressure drop hysteresis in packed beds was concluded in combination of experimental evidence reported in literature.

Growth of Pseudomonas delafieldii R-8 and Biodegradation of Dibenzothiophene in Aqueous Solution

LUO Ming-fang; JIANG Cheng-ying; XING Jian-min; GOU Zhong-xuan; LI Shan; LIU Hui-zhou; CHEN Jia-yong

. 2003, 3(3):  0-0. 

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Pseudomonas delafieldii R-8 isolated from coal contaminated soils in our laboratory could metabolize DBT to 2-hydroxybiphenyl via the sulfur-specific pathway. Effects of initial pH, sources of carbon and nitrogen of the culture media were investigated by using DBT as the sole source of sulfur in aqueous phase. It was indicated that this strain grew well in the pH range of 6~9 and the optimal temperature for growth was 30oC. Glycerol was the optimal carbon source and the optimal concentration was 10 g/L. Organic nitrogen sources including yeast extract, bacto-typtone and beef typtone were conducive to the growth of this strain, but repressed the expression of the desulfurization activity of R-8 even in the presence of DBT. Ammonia acetate was the appropriate source of nitrogen at the concentration of 1.6 g/L. Although sodium sulfate, dimethyl sulfoxide, methionine, cysteine and DBT could be used as the sole sources of sulfur respectively, these sulfur-containing compounds except DBT could not induce the expression of the biodegradation activity of R-8.

Experiment of Optimizing Gas–Particle Flow Regime in the Square-section Circulating Suspension Bed

WANG Cui-ping; YANG Ye; LI Ding-kai; LU Zi-an

. 2003, 3(3):  0-0. 

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In order to develop the advanced flue gas desulphurization (FGD) technology, a cold circulating suspension bed facility with a cross section of 400 mm′400 mm was built. Air and glass granules with a mean diameter of 40 mm were used in experiment. A dual-optic density probe was used to measure the particle concentration and distribution changes with bed parameters, such as air jet entrance at the bed bottom, top structure and inner structure, superficial air velocity, circulating flow rate. The influence of some factors on the wall and corner particle back-flow was analyzed too. The experimental results show that it is necessary to optimize the geometrical configuration and choose suitable working parameters of the circulating suspension bed to improve desulphurization efficiency.

Production of 1,3-Propanediol by Klebsiella pneumoniae in Two Stage Two Substrate Fermentation

YANG Dong; LI Chun; DU Chen-yu; ZHANG Yan-ping; CAO Zhu-an

. 2003, 3(3):  0-0. 

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Based on the understanding that the cyanobacterial glycogen biosynthesis is a competitive pathway to cyanobacterial PHB biosynthesis, a genetically engineered cyanobacterium was constructed by partially replacing the agp gene encoding the ADP-glucose pyrophosphorylase involved in cyanobacterial glycogen synthesis by an erythromycin resistance cassette. The obtained mutant propagated faster and the final biomass was higher against its wild-type species, which indicated a much higher photosynthetic efficiency in the mutant. No glycogen was detected in the mutant. Under the photoautotrophic condition, the intracellular PHB content was improved to 15% of the dry weight as compared to 3.4% in the wild-type strain.

Removal of Arsenite and Arsenate from Solid Herb Samples by Supercritical CO2 Extraction with Ion-pairing

GUAN Yan-fen; WANG Tao

. 2003, 3(3):  0-0. 

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The new method to reduce sintering temperature of WC-Co cemented carbide is studied by submicron WC and trace element additive, with differential thermal analysis and metallographic examination. The sintering temperature can be reduced to 960oC when the average grain size of WC powders is 1.65 μm. The purpose is to avoid thermal deterioration on pre-implanted diamond in the premise of keeping the mechanical properties of WC-Co cemented carbide.

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

. 2003, 3(3):  0-0. 

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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.

Electrodeposited Ultrafine Metal Particles in Pores of Porous Anodic Films of Aluminum

LI Ling-chuan; LU Li-zhu; ZHANG Yi

. 2003, 3(3):  0-0. 

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Uniform AgBr nanoparticles were prepared in microemulsions containing cyclohexane, Triton X-100, n-pentanol and aqueous solution. By changing the reactant molar ratios, AgBr nanowires were obtained in this system. Transmission electron microscopy（TEM）was utilized to characterize the morphology of AgBr products. It is found that reactant molar ratio has important influence on the shape of final products.

Foaming Behavior in Molten Slag Caused by Decomposition of Carbonate Minerals

NIU Qiang;CHU Shao-jun;WU Keng;WANG Ying

. 2003, 3(3):  0-0. 

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The circulating extraction of polysaccharides and betaine from Cistanche deserticola enhanced with ultrasonic wave were investigated. C. deserticola was comminuted to the size of 40 meshes and extracted with ultrasonic wave power of 1000 W in water at 40oC for 10 min. Under the above optimal conditions, the extracted amount of polysaccharides was 46.9 mg/g and that of betaine was 136.5 mg/g, which corresponded to 107.3% and 103.8% of those extracted with reflux in boiling water for 7 h.

Investigation of Leaching Arsenic-bearing Sulfide Copper Concentrate by Ferric Bacterium Solution

ZHOU E; LIU Zhong-hua; CHEN Wen; XIE Hai-yun; YUAN Zhang-fu;

. 2003, 3(3):  0-0. 

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The fluctuation of particle impact pressure and the stochastic characteristic of time series signal are investigated. Analysis shows that the fluctuation of the particle impact pressure has close relationship with the motion of bubbles. The particle pressure measured in experiments is the result of the momentum transfer of a body of solids in the wake of a bubble striking an object. Stochastic signals are also simulated using auto regression [AR(p)] model and the results are very similar to the real signals.

Phase Equilibrium of the Quaternary K2SO4–(NH4)2SO4–CO(NH2)2–H2O System at 25oC

ZHANG Yong-jie; CAO Ji-lin; LI Lin; REN Bao-shan

. 2003, 3(3):  0-0. 

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The solubilities of both ternary K2SO4–CO(NH2)2–H2O and (NH4)2SO4–CO(NH2)2–H2O systems and the quaternary K2SO4–(NH4)2SO4–CO(NH2)2–H2O system were measured at 25oC. On the basis of Pitzer electrolyte solution theory, the experimental results were calculated and the calculated values agree with the experimental data. According to the phase equilibrium of the quaternary system of K2SO4–(NH4)2SO4–CO(NH2)2–H2O at 25oC, it is found that no double salt is formed by K2SO4 or (NH4)2SO4 with CO(NH2)2, and thus the phase equilibrium of the quaternary system can be calculated with the ternary system interaction coefficients.