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Rate Equation of Small Particle-Air Bubble Attachment in Turbulent Flow of Flotation Cells

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 185-191页

作者： Shouci Lu Jingyong Guo(Resources Engineering School, university of Science and technology beijing, beijing 1 00083. China) Resources Engineering School University of Science and Technology Beijing Beijing 100083 China

A rate equation of small particle-air bubble attachment in the turbulent now of flotation cells has beenderived. The equation, integrating both the collision probability and adhesion probability together, represents theprobability of attachment between particle and bubble in the turbulent flow. 'Capture efficiency' f(a) is introducedinto the rate equation to reflect the influence of energy hairier on the attachment rate. Three typical situations of particle-bubble interaction in flotation process have been discussed. For a completely hydrophobic particle-bubble system,f(a) = 1. This means that all collision leads to attachment. Whereas for hydrophilic particle-bubble systems, .f(a) =0. Thus no adhesion of particle on bubble occurs at all. In real notation circumstances, however, there always existsa certain energy barrier between the particle and the bubble. Therefore, f(a) = 0～1. In such cases, not all collisionsresult in particle-bubble attachment.

关键词： rate equation turbulent flow flotation cell capture efficiency

Nonlinear Theory on Dynamic Controlling Interface Patterns DuringSolidification of a Dilute Binary Alloy

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International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 253-258页

作者： Zidong Wang Hanqi Hu(Material Science and Engineering School, university of Science and technology beijing, beijing 100083. China) Material Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

In non-equilibrium nonlinear region, the nonlinear equations of time dependence of perturbation amplitude at the solid/liquidinterface during solidification of a dilute binary alloy are established on the base of assuming that there is local equilibrium at the solid/liquid interface and considering that curvature, temperature and composition at the solid/liquid interface which are related to the perturbation amplitude are nonlinear. As a result, patterns at the solid/liquid interface during solidification process, which is from nonsteadystate to steady state can be controlled by these nonlinear equations.

关键词： nonlinearity solidification, dilute binary alloy, dynamic control

The evolution and morphological stability of a spherical crystal

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Science China(Technological Sciences) 2008年第3期51卷 225-243页

作者： CHEN MingWen1,2, WANG ZiDong2 & XU JianJun3.4 1 School of Applied Sciences, university of Science and technology beijing, beijing 100083. China 2 School of Materials Science and Engineering, university of Science and technology beijing, beijing 100083. China 3.School of Mathematical Sciences, Nankai university, Tianjin 3.0071, China 4 Department of Mathematics and Statistics, McGill university, Montreal H3. 2K6, Canada 1. School of Applied Sciences University of Science and Technology Beijing Beijing 100083 China 2. School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China 3. School of Mathematical Sciences Nankai University Tianjin 300071 China 4. Department of Mathematics and Statistics McGill University Montreal H3A 2K6 Canada

The growth model of a spherical crystal in the undercooled melt including the surface energy, interfacial kinetics and convective flow is established. The effect of the convective flow induced by a small far field flow on the evolution and morphological stability of the interface of the spherical crystal is studied. The interface shape of the spherical crystal, which is affected by the far field flow, and the dispersion relation of the growth rate of amplitude of the perturbed interface are derived. It is shown that the convection induced by the far field flow makes the interface of the growing spherical crystal further grow in the upstream direction of the far field flow and inhibit growth in the downstream direction; the interface of the decaying spherical crystal further decays in the upstream direction and inhibits decay in the downstream direction. The theoretical result suggests that both the growth of the sphere in the upstream direction and the decay of the sphere in the downstream direction make the spherical crystal tend to evolve into an oval; the morphological stability of the interface depends on a certain radius R c such that the spherical crystal is unstable when its radius is greater than R c and stable when its radius is less than R c . The surface energy and interfacial kinetics have strong stabilizing effects on the growth of the spherical crystal. In the meantime interfacial kinetics is a table factor of the interface when the interface of the sphere is growing; it is an unstable factor of the interface when the interface is decaying.

关键词： solid-liquid interface spherical crystal convective flow crystal growth morphological stability

Two possible mechanisms for vortex self-organization

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Science China Earth Sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2, ZHOU Xiuji1 & GAO Shouting3.1. Chinese Academy of Meteorological Sciences, beijing 100081, China 2. Department of Space Information Science, Nanjing university of Information Science and technology, Nanjing 210044, China 3. Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, China 2. Department of Environmental Science Nanjing University of Information Science and Technology Nanjing 210044 China 1. Chinese Academy of Meteorological Sciences Beijing 100081 China 3. Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

A Probe into China's Near Term Finished Petroleum Products Market

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China Petroleum Processing & Petrochemical technology 2009年第3期11卷 1-4页

作者： Duan Yanting Yin Zhe (beijing university of technology,beijing 100124) beijing university of technology Beijing 100124 China

This article described the changes in consumption of finished petroleum products in China since 2008, referring to the international economic environment that has reversed the consumption of finished oil products, and China＇s domestic economic situation and oil pricing policy and major factors related with changes in industrial sectors. This article, by making projections on future market trends, has estimated that in the foreseeable future the domestic finished oil products market will be glutted with oil products that will exceed the demand.

关键词： market finished petroleum product consumption analysis

Process optimization of reaction of acid leaching residue of asbestos tailing and sodium hydroxide aqueous solution

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Science China(Technological Sciences) 2009年第1期52卷 204-209页

作者： DU GaoXiang1,3. ZHENG ShuiLin2 & DING Hao1 1 School of Materials Science and technology, China university of Geosciences (beijing), beijing, 100083. China 2 School of Chemical and Environment Engineering, China university of Mining and technology (beijing), beijing 100083. China 3.Hebei Qinghe Refractory Group Co. Ltd., Xingtai 054804, China 1. School of Materials Science and technology China University of Geosciences (Beijing) Beijing 100083 China 3. Hebei Qinghe Refractory Group Co. Ltd. Xingtai 054804 China 2. School of Chemical and Environment Engineering China University of Mining and Technology (Beijing) Beijing 100083 China

Silica is the major component of the acid leaching residue of asbestos tailing. The waterglass solution can be prepared by the reaction of the residue with sodium hydroxide aqueous solution. Compared to the high temperature reaction method, this process is environmental friendly and low cost. In this paper, the reaction process of the residue and the sodium hydroxide aqueous solution is optimized. The optimum reaction process parameters are as follows: the usage of sodium hydroxide is 26.4 g/100 g acid leaching residue, the reaction temperature is 90℃, the reaction time is 1 h, and the ratio of the liquid/solid is 2.0. The significance sequence of the process parameters to the alkali leaching reaction effect is the usage of sodium hydroxide > the ratio of the liquid/solid > the reaction time > the reaction temperature. The significance sequence to the leaching ratio of SiO2 is the ratio of the liquid/solid > the usage of sodium hydroxide > the reaction time > the reaction temperature. The significance sequence to the modulus of the sodium silicate is the ratio of the liquid/solid > the usage of sodium hydroxide > the reaction time > the reaction temperature. Under the optimum conditions, the leaching ratio of the SiO2 is 77.5%, and the modulus of the sodium silicate is 3.15. The XRD analysis result indicates that the major components of the alkali leaching residue are serpentine, talc, quartz and some albite.

关键词： asbestos tailing acid leaching residue sodium hydroxide process optimization

Spatio-temporal pattern analysis of single-trial EEG signals recorded during visual object recognition

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Science China(Information Sciences) 2011年第12期54卷 2519-2527页

作者： WANG ChangMing 1 , HU XiaoPing 3., YAO Li 1,2 , XIONG Shi 2 & ZHANG JiaCai 2 1 National Key Laboratory of Cognitive Neuroscience and Learning, beijing Normal university, beijing 100875, China 2 College of Information Science and {3., beijing Normal university, beijing 100875, China 3.Biomedical Imaging {3. Center, Emory university/Georgia Institute of {3., Atlanta 3.3.2, USA 1. National Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing 100875 China3. Biomedical Imaging Technology Center Emory University/Georgia Institute of Technology Atlanta 30322 USA2. College of Information Science and Technology Beijing Normal University Beijing 100875 China

Object discrimination is a fundamental cognitive function for human brains. In this study, we utilized an analysis approach for single-trial electroencephalography (EEG) to analyze the spatio-temporal activation patterns of visual objects processing in human brains, and attempted to apply it to discriminate different visual objects. The spatial patterns were respectively extracted from scalp EEG and the reconstructed cortical sources, while the experiment participants were perceiving 4 different categories of visual objects (faces, buildings, cats and cars). By classifying the patterns extracted from single-trial EEG, the presented visual objects could be discriminated by a computer, and the classification accuracies may provide a quantitative index to evaluate the spatial differences of the brain activations related to different visual objects. Our results demonstrated that the spatial patterns on both the scalp and the sources levels resulted in higher classification accuracies than chance rate. We also examined the classification results using temporally non-overlapping time intervals of different event-related potential (ERP) components. The temporal changes of classification accuracies may reflect the temporal distribution of the discriminative information in the EEG responses. The present pattern extraction and classification methods may compose a computational model for single-trial EEG data analysis in investigations of the spatio-temporal activation patterns for object recognition. These spatio-temporal patterns in EEG may be useful to identifying the discriminative spatial areas and time stages to improve the accuracies and efficiencies of object discrimination. In addition, investigating and utilizing humans'cognitive mechanisms of object recognition may improve computers' processing efficiency of visual information.

关键词： EEG spatio-temporal pattern object recognition single-trial analysis visual information processing

Seismic wave propagating in Kelvin-Voigt homogeneous visco-elastic media

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Science China Earth Sciences 2006年第2期49卷 147-153页

作者： YUAN Chunfang1, PENG Suping1, ZHANG Zhongjie2 & LIU Zhenkuan3.1. China university of Mining & technology, beijing 100083. China 2. Institute of Geophysics, Chinese Academy of Sciences, beijing 100101, China 3. Exploration and Development Research Institute of Daqing Oilfield, Daqing 163.12, China 1. China university of Mining & technology Beijing 100083 China 2. Institute of Geophysics Chinese Academy of Sciences Beijing 100101 China 3. Exploration and Development Research Institute of Daqing Oilfield Daqing 163712 China

This paper studies, under a small disturbance, the responses of seismic transient wave in the visco-elastic media and the analytic solution of the corresponding third-order partial differential equation. A plane wave solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differ-ential equation with a pulse source is obtained. By the principle of pulse stacking of particle vibration, the result is extended to the solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differential equation with any source. The velocities of seismic wave propagating and the attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are discussed. The velocities of seismic wave propagating and the coefficient of attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are derived, expressed as functions of density of the media, elastic modulus and visco-elastic coefficient. These results can be applied in inversing lithology parameters in geophysical prospecting.

关键词： Kelvin-Voigt visco-elastic velocity attenuation seismic wave.

Thermodynamic properties and mixing thermodynamic parameters of binary homogeneous metallic melts

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Rare Metals 2003年第1期22卷 25-32页

作者： ZHANG ManMetallurgical Engineering School, university of Science and technology beijing, beijing 100083. China Metallurgical Engineering School University of Science and Technology Beijing 北京 100083

After the investigation on the thermodynamic properties and mixingthermodynamic parameters of binary homogeneous metallic melts involving compound, peritectic as wellas solid solution, it was found that the equations of mixing free energy DELTA G^m and excess freeenergy DELTA G^(XS) of them can he expressed by the following equations: DELTA G^m = SIGMA x [SIGMAN_i DELTA G_I^(THETA) + RT(SIGMA N_j ln N_j + SIGMA N_i ln N_i )] and DELTA G^(XS) = DELTA G^m -RT(a ln a + b ln b), respectively.

关键词： metallic melt mixing thermodynamic parameter coexistence theory activity mass action concentration