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The mathematical model of wetting angle of heterogeneous nucleation

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science china(Technological sciences) 2004年第4期47卷 391-397页

作者： HUANG Cheng1, SONG Bo1, MAO Jinghong2.& ZHAO Pei3 1. School of Metallurgical and Ecological engineering, university of science and technology beijing, {2. 100083, china 2. School of Material science, university of science and technology beijing, {2. 100083, china 3. Central Iron and Steel research institute, {2. 100081, china School of Metallurgical and Ecological engineering University of Science and Technology Beijing Beijing China School of Material science University of Science and Technology Beijing Beijing China Central Iron and Steel research institute Beijing China

The heterogeneous nucleation has been analyzed in terms of the thermodynamic theory, and the mathematical model of wetting angle of heterogeneous nucleation has been developed based on the dynamic requirements of hetero- and homogeneous nucleation. With the wetting angel model, the wetting angles of different catalysts in liquid iron have been calculated. The result shows that the wetting angle of most catalysts is smaller than 40, and the value of f() is far less than 1. The wetting angles of TiN, TiC and RE2.3 are smaller, while the wetting angle of MnO is bigger among the ordinary nucleation catalysts. The wetting angles calculated by this model are in agreement with the results of other research work.

关键词： heterogeneous nucleation, mathematical model, wetting angle, undercooling.

On three-dimensional geological modeling and visualization

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science china Earth sciences 2004年第8期47卷 739-748页

作者： WU Qiang1 & XU Hua2.1. Department of Resource Exploitation engineering, china {2. of Mining and technology, beijing 100083, china 2. beijing institute of Petrochemical technology, beijing 102.17, china Department of Resource Exploitation engineering China University of Mining and Technology Beijing China beijing institute of Petrochemical {2. Beijing China

The technology of 3D geological modeling will bring about great changes in the methods of geological data acquiring, storing, processing and displaying. However, no perfect or convenient software systems have been developed up to now since the geologic data which re-flect geological entities bear the feature of diversity, uncertainty and complexity. Some supervoxel models, mathematical models of fault and geometrical models of fold have been contrived so as to show the space geometric configuration of the complicated geologic structures. The application-oriented system architecture for 3D geological modeling is established; and a novel design concept based on spatial data processing is also proposed with the technology of solid modeling as its core and the application of models as its objective. Theories and methods for 3D geological modeling will hopefully be enriched and developed. In the light of these theories and methods, a feature-based navigation visualization technique is also put forward in the paper. By integrating geo-database, graphics libraries and KBS with 3D dynamic simulation systems, geologists will be able to capture the partial characteristics and whole structure embodied in the geological data in a direct-viewing, figurative and accurate manner.

关键词： 3D geological modeling,geometrical model,system architecture,visualization

The precipitation and effect of nano nitrides in HSLC steel

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science china(Technological sciences) 2008年第7期51卷 989-998页

作者： FU Jie1, LIU YangChun1,2.& WU HuaJie1,3 1 School of Metallurgical and Ecological engineering, university of science and technology beijing, {2. 100083, china 2.Shougang technology research institute, Shougang (Group) Corporation, {2. 100041, china 3 Metallurgical engineering research institute, university of science and technology beijing, {2. 100083, china School of Metallurgical and Ecological engineering University of Science and Technology Beijing Beijing China Shougang technology research {2. Shougang (Group) Corporation Beijing China Metallurgical engineering research {2. University of Science and Technology Beijing Beijing China

The existing forms of N and Al in HSLC (high strength low carbon) steel produced by TSCR (thin slab casting and rolling process), the precipitation thermodynamics and kinetics of AlN, and its effects on structure and mechanical property are studied. The experimental results show that only a small quantity of nitrogen is com- bined into AlN in HSLC steel produced by TSCR and most of the nitrogen in steel is still free nitrogen. Aluminum-nitride is mainly precipitated during the period of slow air cooling after coiling, but not during rolling and water cooling. The acid-soluble aluminum has no obvious effect on the grain size and mechanical property of HSLC steel produced by TSCR whose acid-soluble aluminum content is 0.005%―0.043%. The precipitation of AlN is not the main cause of grain refinement of HSLC steel produced by TSCR, nor is AlN the dominating precipitate that has precipitation strengthening effect. The nano nitrides are not pure AlN, but have complex compositions.

关键词： thin slab casting and rolling high strength low carbon steel AlN nano nitride precipitation strengthening

Effect and mechanism of stresses on rock permeability at different scales

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science china Earth sciences 2006年第7期49卷 714-723页

作者： YIN Shangxian1 & WANG Shangxu2.1. Safety engineering College, North china {2. of science and technology, Yanjiao, beijing 101601, china 2. Key Laboratory of Geophysics Exploration, china university of Petroleum, beijing 100083, china Safety engineering College North China Institute of Science and Technology Yanjiao Beijing China Key Laboratory of Geophysics Exploration China University of Petroleum Beijing China

The effect of geo-stress fields on macroscopic hydro-geological conditions or micro-cosmic permeability of water-bearing media should follow some laws or principles. Cases study and tests show that: (1) At macro-geologic large scale, deformed and crashed rocks which were induced by geo-stress fields changing provided space for groundwater storage and flow. Groundwater adjusts water-bearing space and dilatants fractures by flowing and press transferring. Coupling of liquid and solid can be implemented for rocks and groundwater. Although tectonic fields witness several times of change and build-up in geological time, stress fields forming regional tectonic framework are coherent with seepage fields, orientation of the maximum horizontal stress demonstrates main seepage direc-tions. (2. At macro-geologic middle scale, zones of stresses changing sharply, quite low stresses, stress or shear concentration can be used to show locations and types of main fractures, zones of geo-stresses changing equably can be acted as normal base media zones of tri-porosity media. (3) At micro-geologic small scale, tri-porosity media include fractured rocks, porous rocks and capillary rocks. Investigations indicate that porosity or permeability is functions of effective stresses, and po-rosity or permeability changing rules of porous rocks with variation of effective stresses can be de-scribed as the index model, the model of power exponent functions is suitable for those of fractured rocks, the model of the second power parabola for capillary rocks. The porosity and permeability loss in fractured rocks, which are greater than that in porous rocks, are shown by calculation of effective compressive coefficient and closing pressure in cracks. The calculations can also explain the mecha-nism why porosity changes are always larger than permeability changes. It is proved by the thick wall cylinder theory that the second power parabola relation between porosity or permeability loss and effective

关键词： geo-stress fields, seepage fields, tri-porosity media, effective stresses, permeability, porosity,scale.

Final Temperature Prediction Model of Molten Steel in RH-TOP Refining Process for IF Steel Production

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Journal of Iron and Steel research International 2012年第3期19卷 1-5页

作者： WANG Yu-nan1, BAO Yan-ping1, CUI Heng2. CHEN Bin3, JI Chen-xi3 (1. State Key Laboratory of Advanced Metallurgy, university of science and technology beijing, beijing 100083, {2. 2. engineering research institute, university of science and technology beijing, beijing 100083, {2. 3. Shougang research institute of technology, beijing 100041, {2.) State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing China engineering research {2. University of Science and Technology Beijing Beijing China Shougang research institute of {2. Beijing China

In order to precisely control the final temperature of molten steel in RH （Ruhrstahl Heraeus）-TOP blowing refining, the final temperature prediction models of molten steel in RH-TOP blowing refining process for Interstitial Free （IF） steel production were established under the condition of oxygen blowing and non-oxygen blowing respec- tively. The results show that the beginning molten steel temperature of refining and the amount of added scrap were influential factors, the baking temperature in vacuum chamber was a factor that had small influence. When the model was operated, the hitting probability was above 95%（under the condition of both oxygen blowing and non-oxygen blo- wing） of prediction deviation ±10℃. The accuracy is analyzed.

关键词： RH-TOP molten steel temperature prediction model

research progress in synthesis and catalysis of polyoxometalates

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Progress in Natural science:Materials International 2005年第5期15卷 385-394页

作者： GONG Yun1, HU Changwen1* and LIANG Hong2.1. Department of Chemistry, School of science, the institute for Chemical Physics, {2. institute of technology, {2. 100081, china 2. Chemical Industry Press, {2. 10002., china) Sch. of Sci Inst. for Chem. Phys. Beijing Inst. of Technol. Beijing 100081 China Chem. Indust. Press Beijing 100029 China

Recent progress in the synthetic chemistry and catalysis of polyoxometalates (POMs) is reviewed. The novel POMs and their derivatives emerging in nearly three years (2.02.2.04) are introduced, including POMs with novel structure, POMs-organic hybrid compounds and host-guest complexes. Our review is focused on the elaboration of POMs' supramolecular chemistry.

关键词： polyoxometalates hybrid host-guest structure supramolecule catalysis.

Analysis for twinning and slip in face-centered cubic crystals under axisymmetric co-deformation

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science china(Technological sciences) 2006年第5期49卷 521-536页

作者： CHEN Zhiyong1,2. CAI Hongnian1, ZHANG Xinming2. WANG Fuchi1 & TAN Chengwen1,3 1. School of Material science and engineering, {2. institute of technology, {2. 100081, china 2. School of Material science and engineering, Central South university, Changsha 410083, china 3. School of Material science and engineering, {2. university of Aeronautics and Astronautics, {2. 100083, china School of Material science and engineering Beijing Institute of Technology Beijing China School of Material science and engineering Central South University Changsha China School of Material science and engineering Beijing University of Aeronautics and Astronautics Beijing China

The maximum work principle of Bishop-Hill was developed to analyze the axisymmetric co-deformation in face-centered cubic crystals (f.c.c.) for twinning on {111} 112.and slip on {111} 110 systems. The influence of ξ , the ratio of critical re- solved shear stress for twinning to slip, on the yield stress states and corresponding active slip or/and twinning systems for orientations in the standard stereographic triangle of cubic crystal was investigated systematically. The Taylor factors and the anisotropy of yield strength for three important orientations [100], [110] and [111] in orientation space were analyzed. It is found that the yield strength asymmetry for the case of axisymmetric de- formation of tension and compression can be explained based on the microscopic theory of crystal plasticity. The concept of orientation factor for twinning ability was proposed and the deformation mechanism map in the orientation space was established for the case of axisymmetric deformation. The deformation texture formation and development of f.c.c. crystals with low stacking fault energy for axisymmetric tension can be explained qualita- tively on the basis of analyzed results.

关键词： twinning slip face-centered cubic crystals axisymmetric co-deformation Bishop-Hill maximum work principle yield strength anisotropy

A research on the Joining of SiC Composite to 40 Cr Steel

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Journal of university of science and technology beijing 2001年第4期8卷 280-282页

作者： Chengchang Jia, Jianxin Chu, Qingshan Zhao 1) Materials science and engineering,{2., beijing 100083, china 2. beijing Nonferrous Metals research institute, beijing 100081, china Materials science and engineering University of Science and Technology Beijing Beijing 100083 China beijing Nonferrous Metals research {2. Beijing 100081 China

SiC composites and 40 Cr Steels were joined with Ag-Cu-Ti solder in order to develop a new method of joining ceramics to metal. Effects of solder component and process parameters on the joining strength were investigated. The results show that some chemical reactions occur on the jointing interface between ceramics and metal. Higher joining strength is achieved when titanium is 0.2. (mass fraction) in the solder. The thickness of solder also affects the joining characteristics, and 0.2.0.3 mm. thickness of solder is the most suitable.

关键词： ceramics metal joint sintering SiC composites Ag-Cu-Ti solder

Polynomial analysis of canopy spectra and biochemical component content inversion

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science china Earth sciences 2005年第10期48卷 1780-1791页

作者： YAN Chunyan1, LIU Qiang1, NIU Zheng1, WANG Jihua2. HUANG Wenjiang2.& LIU Liangyun 2.1. State Key Laboratory of Remote Sensing science, Jointly Sponsored by the institute of Remote Sensing Applications of Chinese Academy of sciences and beijing Normal university, beijing 100101, china 2. National engineering research Center for Information technology in Agriculture, beijing 100089, china Jointly Sponsored by the institute of Remote Sensing Applications of Chinese Academy of sciences and {2. Normal university National engineering research Center for Information {2. in Agriculture

A polynomial expression model was developed in this paper to describe directional canopy spectra, and the decomposition of the polynomial expression was used as a tool for re-trieving biochemical component content from canopy multi-angle spectra. First, the basic formula of the polynomial expression was introduced and the physical meaning of its terms and coeffi-cients was discussed. Based on this analysis, a complete polynomial expression model and its decomposition method were given. By decomposing the canopy spectra simulated with SAILH model, it shows that the polynomial expression can not only fit well the canopy spectra, but also show the contribution of every order scattering to the whole reflectance. Taking the first scattering coefficients a10 and a01 for example, the test results show that the polynomial coefficients reflect very well the hot spot phenomenon and the effects of viewing angles, LAI and leaf inclination angle on canopy spectra. By coupling the polynomial expression with leaf model PROSPECT, a canopy biochemical component content inversion model was given. In the simulated test, the canopy multi-angle spectra were simulated by two different models, SAILH and 4-SCALE re-spectively, then the biochemical component content was retrieved by inverting the coupled polynomial expression + PROSPECT model. Results of the simulated test are promising, and when applying the algorithm to measured corn canopy multi-angle spectra, we also get relatively accurate chlorophyll content. It shows that the polynomial analysis provides a new method to get biochemical component content independent of any specific canopy model.

关键词： polynomial expression, canopy spectra, decomposition, biochemical component content, inversion.