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CAlCUlATION OF SECOND PHASE PARTIClE-GRAIN BOUNDARY INTERACTION RANGE

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Acta Metallurgica Sinica(English letters) 2008年第1期21卷 8-14页

作者： x.l. Wang Y.H. Wei W. Wang l.F. Hou College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 China Baosteel Technology Center Baoshan Iron ＆ Steel Co. Ltd. Shanghai 201900 China Manuscript received 20 December 2006

On the basis of the grain boundary equation by HeUman and corresponding analysis of Worner, this article deals with the interaction range between the second-phase particle （SPP） and grain boundary （GB） as viewed from the applicability of grain boundary equation. Also, a new expression describing the interaction range has been derived, which solves the problem in theory that the interaction range between SPP and GB can only be qualitatively analyzed previously. It is shown that given the interaction position between SPP and GB, the interaction range can be quantitatively determined by use of this expression.

关键词： Second-phase particle Grain boundary Pinning force Surface free energy

THEORETICAl STUDY OF GIANT MAGNETO-IMPEDANCE IN AMORPHOUS FIlMS WITH lONGITUDINAl MAGNETIC ANISOTROPY

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Acta Metallurgica Sinica(English letters) 2000年第4期13卷 995-1000页

作者： Yu, J.Q. Zhou, Y. Cai, B.C. Zhao, x.l. Shanghai Jiaotong Univ Shanghai China

Giant magneto-impedance (MI) effect in thin films with longitudinal magnetic anisotropy was studied theoretically. The effective permeability of films as a function of external magnetic field Ha, anisotropy field and other parameters of films was presented by landau-lifshitz-Gilbert theory. The theoretical results agree well with the experimental data, which shows a strong dependence of the impedance on the applied magnetic field.

关键词： Electric currents Magnetic anisotropy Magnetic fields Skin effect

Chaos,Transport and Mesh Convergence for Fluid Mixing

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Acta Mathematicae Applicatae Sinica 2008年第3期24卷 355-368页

作者： H. lim Y. Yu J. Glimm x.l. li D.H. Sharp Department of Applied Mathematics and Statistics Stony Brook University Stony Brook NY 11794-3600 USA Computational Science Center Brookhaven National Laboratory Upton N~ 11793-6000 USA los Alamos National laboratory Los Alamos NM USA

Chaotic mixing of distinct fluids produces a convoluted structure to the interface separating these fluids. For miscible fluids （as considered here）, this interface is defined as a 50% mass concentration isosurface. For shock wave induced （Richtmyer-Meshkov） instabilities, we find the interface to be increasingly complex as the computational mesh is refined. This interfacial chaos is cut off by viscosity, or by the computational mesh if the Kolmogorov scale is small relative to the mesh. In a regime of converged interface statistics, we then examine mixing, i.e. concentration statistics, regularized by mass diffusion. For Schmidt numbers significantly larger than unity, typical of a liquid or dense plasma, additional mesh refinement is normally needed to overcome numerical mass diffusion and to achieve a converged solution of the mixing problem. However, with the benefit of front tracking and with an algorithm that allows limited interface diffusion, we can assure convergence uniformly in the Schmidt number. We show that different solutions result from variation of the Schmidt number. We propose subgrid viscosity and mass diffusion parameterizations which might allow converged solutions at realistic grid levels.

关键词： Schmidt number mass diffusion turbulence multiphase flow

NUMERICAl SIMUlATION OF PARTIClE SEPARATION IN AN OIl-SAND SEPARATOR

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Journal of Hydrodynamics 2001年第1期13卷 81-85页

作者： Wei, x.l. Tian, W.D. Wang, J.M. Sheng, H.Z. Inst. of Mechanics Chinese Acad. of Sci. Beijing 100080 China

The gathering systems of crude oil are greatly endangered by the fine sand and soil in oil. Up to now, how to separate sand from the viscid oil is still a technical problem for oil production at home or abroad. Recently, Institute of Mechanics in Chinese Academy of Sciences has developed a new type of oil-sand separator, which has been applied successfully in oil field in situ. In this paper, the numerical method of vortex-stream function is used to predict the liquid-solid separating course and the efficiency for this oil-sand separator. Results show that the viscosity and particle diameter have much influence on the particle motion. The calculating separating efficiency is compared with that of experiment and indicates that this method can be used to model the complex two-phase flow in the separator.

关键词： Computer simulation Crude petroleum Petroleum engineering Separators

Effects of temperature and thermally-induced microstructure change on hydraulic conductivity of Boom Clay

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第3期9卷 1-13页

作者： W.Z. Chen Y.S. Ma H.D. Yu F.F. li x.l. li x. Sillen Research Centre of Geotechnical and Structural Engineering Shandong University Jinan Shandong 250061 China State Key laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China University of Chinese Academy of Sciences Beijing 100049 China European Underground Research Infrastructure for Disposal of Nuclear Waste in Clay Environment EIG Euridice Mol 2400 Belgium ONDRAF/NIRAS Brussel 1210 Belgium

Boom Clay is one of the potential host rocks for deep geological disposal of high-level radioactive nuclear waste in Belgium. In order to investigate the mechanism of hydraulic conductivity variation under complex thermo-mechanical coupling conditions and to better understand the thermo-hydromechanical(THM) coupling behaviour of Boom Clay, a series of permeability tests using temperaturecontrolled triaxial cell has been carried out on the Boom Clay samples taken from Belgian underground research laboratory(URl) HADES. Due to its sedimentary nature, Boom Clay presents acrossanisotropy with respect to its sub-horizontal bedding plane. Direct measurements of the vertical(Kv)and horizontal(Kh)hydraulic conductivities show that the hydraulic conductivity at 80℃ is about 2.4 times larger than that at room temperature(23℃), and the hydraulic conductivity variation with temperature is basically reversible during heatingecooling cycle. The anisotropic property of Boom Clay is studied by scanning electron microscope(SEM) tests, which highlight the transversely isotropic characteristics of intact Boom Clay. It is shown that the sub-horizontal bedding feature accounts for the horizontal permeability higher than the vertical one. The measured increment in hydraulic conductivity with temperature is lower than the calculated one when merely considering the changes in water kinematic viscosity and density with temperature. The nuclear magnetic resonance(NMR) tests have also been carried out to investigate the impact of microstructure variation on the THM properties of clay. The results show that heating under unconstrained boundary condition will produce larger size of pores and weaken the microstructure. The discrepancy between the hydraulic conductivity experimentally measured and predicted(considering water viscosity and density changes with temperature) can be attributed to the microstructural weakening effect on the thermal volume change behaviour of Boom Clay. Based on the ex

关键词： Boom Clay Permeability Thermal effect Anisotropy Microstructure

Trends in Extremes of Surface Humidity, Temperature, and Summertime Heat Stress in China

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Advances in Atmospheric Sciences 2001年第5期18卷 742-751页

作者： Julian x.l. Wang and Dian J. Gaffen NOAA/ Air Resources laboratory, Silver Spring, MD, 20910, USA NOAA/ Air Resources laboratory Silver Spring USA

In the past half century, the mean summertime temperature in China has increased, with nights warm- ing more than days. Using surface station observations, we show that the frequency of extreme heat-stress events in China, caused by extremely hot and humid days as well as by heatwaves lasting for a few days, has increased over the period from 1951 to 1994 When humidity is high, hot weather can cause heat stress in humans. The increased heatrstress trend may pose a public health problem

关键词： Trend detection Climate change Public health

Synthesis and Isolation of Diastereomers of Optically Active Cyclomercurated Ferrocenylimines

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Chinese Chemical letters 2000年第11期11卷 975-978页

作者： Wu Y.J. Cui x.l. Song M.P. Zhou N. Du C.x. Zhu Y. Department of Chemistry Zhengzhou University Zhengzhou 450052 China Henan Prov. lab. of Appl. Chemistry Zhengzhou University Zhengzhou 450052 China

Asymmetric cyclomercuration of chiral ferrocenylimines (+)-(R)-2 and (-)-(S)-2 with mercuric acetate and subsequent treatment by lithium chloride gave a mixture of diastereomeric cyclomercurated ferrocenylimines. The four enantiomeric pure compounds with both planar and central chirality were isolated from the two mixtures by the thin layer chromatography.

关键词： Sc KBr IR Hg Cl Synthesis and Isolation of Diastereomers of Optically Active Cyclomercurated Ferrocenylimines

THERMAl STABIlITY OF NON-EQUIlIBRIUS MICROSTRUCTURE IN MICROAllOYED STEEl DURING REHEATING

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Acta Metallurgica Sinica(English letters) 2007年第5期20卷 313-326页

作者： H.B. Wu H.T. Jiang S.W. Yang D. Tang x.l. He National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 China Dept. of Materials Physics University of Science and Technology Beijing Beijing 100083 China

Cooled in water after isothermal relaxation of deformed austenite for different times, an Nb-bearing microalloyed steel always exhibits synthetic microstructures, in which bainitic ferrite ,dominates. Dislocation configurations and distributions of strain induced precipitates inside bainitic ferrite of samples relaxed for different times were distinct. When compared with the austenite model steel, which maintained fcc structure even at room temperature, the strain induced precipitates were not found in the sample without relaxation whereas these were distributed outside dislocations in sample relaxed for 1000s. Most of the strain induced precipitates distribute along dislocations and pin dislocations in sample relaxed for appropriate time. After bainitic transformation, the dislocations formed in deformed austenite remain to be pinned by the precipitates. When these samples were reheated to and held at 650 or 700℃, the non-equilibrloas microstructures tended to evolve into equilibrioas ones. The sample relaxed for 60s displayed the highest thermo-stability, whereas microstructure evolution was the quickest in the sample relaxed for 1000s even though it was the softest prior to reheating. Dislocations inside laths got rid of pinning of precipitates, and their polygonization became the precursor to the evolution of microstructures during reheated and held, followed by gradual disappearance of lath boundaries caused by dislocation climbing. Finally, recrystallization occurred and polygonal ferrite appeared. By hardness measurement, it was found that softening is not a single process occurring during reheated, in which hardness fluctuates with time. There were two peaks in the hardness-time curve of each sample having undergone relaxation, while single peak occured in the curve of the sample not being relaxed. These results indicated that the thermo-stability of microstructures was determined by their history of formation to a considerable degree.

关键词： bainite reheating strain induced precipitate pinning microstructures evolution

CORROSION BEHAVIORS OF THE ExPOSED SIDE AND UNDERSIDE OF lOW AllOY WEATHERING STEEl IN QINGDAO AND WANNING FOR 18 MONTHS

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Acta Metallurgica Sinica(English letters) 2008年第6期21卷 425-436页

作者： S. T. Wang S. W. Yang K. W. Gao x.l. He Department of Materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China

For 18 months, a newly developed low alloy weathering steel has been exposed in two coastal sites （Qingdao in the north China, Wanning in the south China）. The different corrosion behaviors of the exposed side and the underside of the samples were characterized by x-ray diffraetion （xRD）, polarization curve, electrochemical impedance spectroscopy （EIS）, scanning electron microscopy （SEM）, and N2 adsorption approach. It was found that the samples exhibited higher corrosion rate in Wanning than that in Qingdao. The underside of the samples corrodes more seriously than the exposed side in Qingdao, whereas the result in Wanning is just the reverse. The protection performance of rust layers mainly depends on its compactness and the enrichment of Cu and Cr is a secondary causation. The different compactness of rust layers in the exposed side and the underside originates from different corrosion conditions of the two sides.

关键词： low alloy weathering steel Temperate marine environment Subtropical marine environment Exposed side Underside side