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DEBINDING　mechanism　AND　KINETICS　FOR　PW　IN　PW－WC　FEEDSTOCK　UNDER　AIR　ATMOSPHERE

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中国有色金属学会会刊：英文版 1996年第2期6卷 72-75页

作者： Liang Shuquan Huang Baiyun Qu Xuanhui (National Laboratory for Powder Metallurgy ,Central South University of Technology, Changsha 410083) National Laboratory for Powder Metallurgy Central South University of Technology Changsha 410083 China Service in Department of Materials Science and Engineering Central South University of Technology

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关键词： MIM PW-WC feedstock debinding process mechanism, kinetics

Investigation on property and mechanism of redox wave of methylhesperidine at Hg electrode

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Science China Chemistry 2005年第Z1期48卷 20-24页

作者： ZHENG Jianbin MENG Zuchao ZHANG Hongfang Institute of Analytical Science/Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry Northwest University Xi'an 710069 China Institute of Analytical Science/Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry Northwest University Xi'an 710069 China Institute of Analytical Science/Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry Northwest University Xi'an 710069 China

The voltammetric behaviors of methylhesperidine (MH) were studied by means of linear sweep voltammetry, cyclic voltammetry and normal pulse voltammetry. In the Brit ton-Robinson buffer solutions with pH values from 2.05 to 6.37, MH could yield three reduction waves PC1, PC2 and PC3. PC1 wave is an adsorptive pre-wave. PC2 wave is an irreversible reduc tion of pre-protonated MH involving one electron and one proton. PC3 wave is an irreversible wave of reduction species radical of MH involving one electron.

关键词： voltammetric behavior, polarography, mechanism, reduction, methylhesperidine.

Kinetics and mechanism of the reaction between thiourea and iodate in unbuffered medium

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Science China Chemistry 2004年第6期47卷 480-487页

作者： WANG Shun1,2, LIN Juanjuan1, CHEN Fan1, HU Maolin1, HU Xingen1, HAN Yiping1 & GAO Qingyu2 1.Department of Chemistry and Material Science, Wenzhou Normal College, Wenzhou 325027, China 2. College of Chemical Engineering, China University of Mining and Technology, Xuzhou 221008, China Department of Chemistry and Material Science Wenzhou Normal College Wenzhou China College of Chemical Engineering China University of Mining and Technology Xuzhou China

The reaction between iodate and thiourea has been studied in an unbuffered acidic medium. In excess iodate the reaction shows not only oligooscillations in pH, Pt potential and the concentration of iodide ion, [I?], but also an initial induction period which has the linear relation with initial pH. At the end of the induction period, [I?] decreases sharply and a yellow coloration (due to iodine) appears transiently. While in excess thiourea iodine is produced and finally con- sumed, leaving milky deposits (due to sulfur) at the end of the reaction. The induction period from the start of the reaction to the maximum of [I2] is also directly proportional to initial pH. A 14-step mechanism, including a H+-mediated preequalibrium, Dusman reaction, iodine-sulfur reactions and sulfur-sulfur reactions, is proposed. Computer simulations using this mechanism give good agreement with experiments.

关键词： oligooscillations, pH dynamics, thiourea, iodate, complex reaction mechanism, dynamic simulation.

A theoretical study on nitration mechanism of benzene and solvent effects

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Science China Chemistry 2003年第5期46卷 453-464页

作者：肖鹤鸣陈丽涛居学海姬广富 Department of Chemistry Nanjing University of Science & Technology Nanjing 210094 China Department of Chemistry Nanjing University of Science & Technology Nanjing 210094 China Institute of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 China

Both p and s transition states on the potential energy surface of the nitration of benzene with nitronium ion have been successfully optimized using unrestricted hybrid DFT procedure B3LYP with the triple-zeta 6-311G** basis set without any assumption. Subsequently, a s reactant-complex and a intermediate (Wheland intermediate) were located by the intrinsic reaction coordinate (IRC) calculation. The reaction pathway and the experimental observation lacking the kinetic isotopic effect in the title nitration were confirmed on geometries, atomic charges, energies, IR spectra and thermodynamic properties of all stationary points. The activation energy of 8.370 kJ/mol in the gas phase and the order of 1010 mol·L-1·s-1 of rate constant were obtained for the reaction. The results both in thermodynamics and kinetics show that the electrophilic substitute mechanism is more preferable than the electron transfer mechanism of radical pairs. The solvent effect on the geometries of stationary points and the reaction mechanism were systematically studied for the nitration of benzene with nitronium by self-consistent reaction field (SCRF) technique with different dielectric constants of 5.0, 25.0, 50.0 and 78.5. It was then found that the solvent effect would depress the activation energy and finally make the formation of s-TS without energy barrier in aqueous solution. Furthermore, the linear correlations given by charge migrations of NO2 group, dipole moments of solute, gaps of HOMO and LUMO and solvent stabilization energies in different solvents were demonstrated for both theoretically and experimentally concerned Wheland intermediate.

关键词： benzene, nitronium ion, nitration mechanism, solvent effect, density functional theory.

Formation mechanism and model for sand lens reservoirs in the Jiyang Sub-basin,East China

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Science China Earth Sciences 2004年第Z2期47卷 167-176页

作者： LI Pilong 1, PANG Xiongqi2,3, CHEN Dongxia2,3, ZHANG Shanwen1, JIN Zhijun4 & JIANG Zhenxue2,3 1. Shengli Oil Field Ltd, SINOPEC, Dongying 257051, China 2. University of Petroleum, Beijing 102249, China 3. Key Laboratory of Oil and Gas Accumulation, Ministry of Education, Beijing 102249, China 4. Research Institute of Petroleum Exploration and Exploitation, SINOPEC, Beijing 100083, China Shengli Oil Field Ltd SINOPEC Dongying 257051 China University of Petroleum Beijing 102249 China Key Laboratory of Oil and Gas Accumulation Ministry of Education Beijing 102249 China Research Institute of Petroleum Exploration and Exploitation SINOPEC Beijing 100083 China

The Bohai Bay basin comprises some very important and well documented subtle traps known in China, which have been the major exploration focus and have become a major petroleum play since the 1990s. However, recent exploration showed that the oil-bearing proper-ties of some sand lens reservoirs may vary significantly and the accumulation mechanisms for these lithological subtle traps are not well understood. Based on statistical analysis of oil-bearing properties for 123 sand lens reservoirs in the Jiyang Sub-basin and combined with detailed anatomy of typical sand lens reservoirs and NMR experiments, it has been shown that the structural and sedimentary factors, hydrocarbon generation and expulsion conditions of the sur-rounding source rocks, as well as the petrophysical properties of sand lens reservoirs are the main controlling factors for the formation of sand lens reservoirs. The formation of a sand lens reservoir depends on the interaction between the hydrocarbon accumulation driving force and the resistance force. The driving force is made up of the differential capillary pressure between sandstones and sources rocks and the hydrocarbon diffusion force, and as well as the hydro-carbon expansion force. The resistance force is the friction resistance force for hydrocarbons and water to move through the pore throats of the sand lens. The sedimentary environment, source rock condition and sand reservoir properties can change from unfavorable to favorable depend-ing on the combination of these factors. When these three factors all reach certain thresholds, the sand lens reservoirs may begin to be filled by hydrocarbons. When all of these conditions be-come favorable for the formation of sand lens reservoirs, the reservoir would have high oil satu-ration. This approach has been applied to evaluating the potential of petroleum accumulation in the sand lens reservoirs in the third member of the Neogene Shahejie Formation in the Jiyang Sub-basin.

关键词： sand lens reservoir, accumulation controlling factors, accumulation mechanism, accumulation model, Jiyang Sub-basin.

Experimental study of surface texture and resonance mechanism of booming sand

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Science China Earth Sciences 2007年第9期50卷 1351-1358页

作者： QU JianJun1, ZHANG KeCun1, SUN Bo2, JIANG ShengXiang3, DONG GuangRong1, ZU RuiPing1 & FANG HaiYan 1 Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China 2 Shanghai Institute of Polar Regions, Shanghai 210000, China 3 Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Shanghai Institute of Polar Regions Shanghai 210000 China Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China

The sound-producing mechanism of booming sand has long been a pending problem in the blown sand physics. Based on the earlier researches, the authors collected some silent sand samples from Teng- ger Desert, Australian Desert, Kuwait Desert, beaches of Hainan Island and Japanese coast as well as the soundless booming sand samples from the Mingsha Mountain in Dunhuang to make washing ex- periments. In the meantime the chemical corrosion experiment of glass micro-spheres, surface coating experiment and SEM examination were also conducted. The experimental results show that the sound production of booming sand seems to have nothing to do with the presence of SiO2 gel on the surface of sand grains and unrelated to the surface chemical composition of sand grains but is related to the resonance cavities formed by porous (pit-like) physical structure resulting from a number of factors such as wind erosion, water erosion, chemical corrosion and SiO2 gel deposition, etc. Its resonance mechanism is similar to that of Hemholz resonance cavity. Under the action of external forces, nu- merous spherical and sand grains with smooth surface and porous surface are set in motion and rub with each other to produce extremely weak vibration sound and then become audible sound by human ears through the magnification of surface cavity resonance. However the booming sands may lose their resonance mechanism and become silent sand due to the damping action caused by the invasion of finer particles such as dust and clay into surface holes of sand grains. Therefore, clearing away fine pollutants on the quartz grain surface is an effective way to make silent sand emit audible sound.

关键词： booming sand, surface texture, quartz grain, sound-producing mechanism, Hemholz resonance cavity

An Analysis of the Orthogonal Crank-rocking Lever Spatial mechanism for the Weft Insertion in Rapier Looms

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Journal of Donghua University(English Edition) 2001年第1期18卷 27-31页

作者： Li Kerang(李克让) Chen Ming(陈明) Department of Mechanical Engineering Dong Hua University Shanghai 200051 Department of Mechanical Engineering Dong Hua University Shanghai 200051

On the basis of the analysis of typical orthogonal crankrocking lever spatial mechanism for the weft insertion in rapier looms, the rules of the outputting lever motion and the mechanism pressure-angle variety are studied when the maximum swing angle of rocking lever and the length of outputting lever have different values, and the optimum parameters suitable for motion transmission can be chosen. At the same time some existing shortpoints of the mechanism are also pointed out.

关键词： rapier loom, weft insertion mechanism, motion transmission performance.

Atomic Scale Computer Simulation for Early Precipitation Process of Ni75Al6Vi9 Alloy

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Journal of Materials Science & Technology 2003年第Z1期19卷 17-19页

作者： Yuhong ZHAO Hua HOU Hong XU Yongxin WANG Zheng CHEN Xiaodong SUN Department of Materials Science and Engineering Northwestern Polytechnical University Xian 710072 China Department of Materials Engineering North China Institute of Technology Taiyuan 030051 China Department of Materials Engineering North China Institute of Technology Taiyuan 030051 China Department of Materials Science and Engineering Northwestern Polytechnical University Xian 710072 China Department of Materials Science and Engineering Northwestern Polytechnical University Xian 710072 China The Army Representative Agency in 674 Factory State-Owned Harbin 151005 China

The atomic scale computer simulation for initial precipitation mechanism of Ni75Al6V19 alloy was carried out for the first time by employing the microscopic diffusion equation. The initial precipitation process was invest igated throughsimulating the atomic pictures and calculating the order parameters of the two kinds of ordered phases. Simulationresults show that the γ′ordered phase precipitated earlier than θ ordered phase by congruent ordering+spinodal decomposition mechanism and thus produced a nonstoicheometric γ′ single ordered phase. Then, the nonstoichiometricθ phase precipitated by a non-classical nucleation and growth mechanism at the APBS of γ′ phase.

关键词： Precipitation mechanism, Ni75Al6V19 alloy, γ′ (Ni3Al) ordered phase, θ (Ni3V) ordered phase, Computer simulation

Numerical investigation on detonation cell evolution in a channel with area-changing cross section

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Science China(Physics,Mechanics & Astronomy) 2007年第6期50卷 797-808页

作者： DENG Bo,HU ZongMin,TENG HongHui & JIANG ZongLin Key Laboratory of High Temperature Gas Dynamics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100080,China Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing China

The two-dimensional cellular detonation propagating in a channel with area-changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow ex-pansion and compression on the cellular detonation cell were investigated to illus-trate the mechanism of the transverse wave development and the cellular detona-tion cell evolution. By examining gas composition variations behind the leading shock,the chemical reaction rate,the reaction zone length,and thermodynamic parameters,two kinds of the abnormal detonation waves were identified. To explore their development mechanism,chemical reactions,reflected shocks and rarefac-tion waves were discussed,which interact with each other and affect the cellular detonation in different ways.

关键词： detonation cells, transverse waves, detailed chemical reaction model, numerical simulation The two-dimensional cellular detonation propagating in a channel with area- changing cross section was numerically simulated with the dispersion-controlled dissipative scheme and a detailed chemical reaction model. Effects of the flow expansion and compression on the cellular detonation cell were investigated to illustrate the mechanism of the transverse wave development and the cellular detonation cell evolution. By examining gas composition variations behind the leading shock, the chemical reaction rate, the reaction zone length, and thermodynamic parameters, two kinds of the abnormal detonation waves were identified. To explore their development mechanism, chemical reactions, reflected shocks and rarefaction waves were discussed, which interact with each other and affect the cellular detonation in different ways. ……