检索结果-南通市图书馆

The mathematical model of wetting angle of heterogeneous nucleation

在线全文

学校读者我要写书评

暂无评论

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 {2. Beijing, Beijing 100083. china 2. school of Material science, University of science and {2. Beijing, Beijing 100083. china 3. Central Iron and Steel Research institute, Beijing 100081, china 1. school of Metallurgical and Ecological Engineering University of Science and Technology Beijing 100083 Beijing China 2. school of Material science University of Science and Technology Beijing 100083 Beijing China 3. Central Iron and Steel Research institute 100081 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.

A new DNA algorithm to solve graph coloring problem

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2. Meng Ya3.and Meng Dazhi2.1. National Laboratory of Pattern Recognition,institute of Automation, Chinese Academy of {3.s, Beijing 100080,{2. 2. College of Applied {3.s, Beijing University of technology, Beijing 10002.,{2. 3. school of {3., Beijing institute of technology, Beijing 100081,{2.) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China College of Applied sciences Beijing University of Technology Beijing 100022 China school of science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

On the periodic solutions of a type of differential-iterative equations

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese science Bulletin 1998年第3期43卷 204-206页

作者： GE Weigao 1, LIU Zhengrong 2.and YU Yuanhong 3.1. Department of Applied Mathematics, Beijing institute of technology, Beijing {2., china 2. Department of Mathematics, Yunnan University, Kunming 650091, china 3. institute of Applied Mathematics, C Department of Applied Mathematics Beijing Institute of Technology Beijing China Department of Mathematics Yunnan University Kunming China institute of Applied Mathematics Chinese Academy of Sciences Beijing China

Sufficient conditions for the existence of periodic solutions to a type of nonautonomous differential_iterative equations are given.

关键词： differential_iterative equation periodic solution fixed point.

Allocation of power generating and shipping of Hanjiang upstream cascade

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第8期15卷 733-741页

作者： LIU Junping1* and CHANG Mingqi 2.3.1. school of Civil Engineering and Architecture, Zhejiang University of technology, Hangzhou 3.0014,{2. 2. institute of Water Resources & Hydroelectric Engineering, Xi'an University of technology, Xi'an 710048,{2. 3. Shanxi institute of Water Resources, Taiyuan 03.001,{2.) school of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou 310014 China institute of Water Resources and Hydroelectric Engineering Xi'an University of Technology Xi'an 710048 China Shanxi institute of Water Resources Taiyuan 030001 China

The optimal model and simulating model of the Hanjiang cascade reservoirs operation with one day as its calculating period are established to coordinate the contradictions between power generating and shipping. The optimal model is solved by progressive optimality algorithm method adopting the theory of large system decomposing and coordinating. By analyzing the water allocation results obtained from six schemes, which are two cascades, four cascades and seven cascades joint operation considering shipping or not, the contradiction degree between power generating and shipping is investigated and some joint operation schemes are proposed.

关键词： cascade power generating contradiction shipping optimal operation.

Two possible mechanisms for vortex self-organization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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,{2. 2. Department of Space Information science, Nanjing University of Information science and technology, Nanjing 2.0044,{2. 3. institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 10002.,{2. 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.

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

在线全文

学校读者我要写书评

暂无评论

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 {3. and Engineering, Beijing {2. of technology, Beijing 100081, china 2. school of Material {3. and Engineering, Central South University, Changsha 410083. china 3. school of Material {3. and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083. china 1. school of Material science and Engineering Beijing Institute of Technology Beijing 100081 China 2. school of Material science and Engineering Central South University Changsha 410083 China 3. school of Material science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 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 study of two-dimensional magnetic polaron

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 421-429页

作者： LIU Tao1, ZHANG Huaihong1, FENG Mang1,2.& WANG Kelin1,3.1. school of science, Southwest University of science and technology, Mianyang 62.010, china 2. Wuhan institute of Physics and Mathematics, Chinese Academy of sciences, Wuhan 43.070, china 3. Department of Modern Physics, University of science and technology of china, Hefei 2.002., china school of science Southwest University of Science technology Mianyang 621010 China Wuhan institute of Physics Mathematics Chinese Academy of Sciences Wuhan 430070 China Department of Modern Physics University of Science technology of china Hefei 230026 China

By using the variational method and anneal simulation, we study in this paper the self-trapped magnetic polaron (STMP) in two-dimensional anti-ferromagnetic material and the bound magnetic polaron (BMP) in ferromagnetic material. Schwinger angular momentum theory is applied to changing the problem into a coupling problem of carriers and two types of Bosons. Our calculation shows that there are single-peak and multi-peak structures in the two-dimensional STMP. For the ferromagnetic material, the properties of the two-dimensional BMP are almost the same as that in one-dimensional case; but for the anti-ferromagnetic material, the two-dimensional STMP structure is much richer than the one-dimensional case.

关键词： self-trapped magnetic polaron, bound magnetic polaron, impurity potential, anti-ferromagnet.

Study on Transformation of CaO-Al_2._3.SiO_2.MgO System Inclusions in ZG06Cr13.i4Mo Stainless Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S2期18卷 341-346页

作者： LIU Jian-hui1,3. DONG Han1,3. ZHU Rong2. LI Shi-qi2.(1. institute for Structural Materials,Central Iron and Steel Research institute, Beijing {2.,china 2. school of Metallurgical and Ecological Engineering,University of science and technology Beijing, Beijing 100083.china 3. National Engineering Research Center of Advanced Steel technology, Beijing {2.,china) Cent Iron & Steel Res Inst Inst Struct Mat Beijing 100081 Peoples R China Univ Sci & Technol Beijing Sch Met & Ecol Engn Beijing 100083 Peoples R China Natl Engn Res Ctr Adv Steel Technol Beijing 100081 Peoples R China

This paper aims at generally studying on the inclusions of ZGG06Cr13.i4Mo ultra-low carbon stainless steel used for large scale hydraulic turbine sets. On the basis of analysis the industrial test samples, thermodynamic software FactSage is used to study inclusions transformation process in CaO-SiO2.Al2.3.MgO system while stainless steel is been smelting. The results illustrate the inclusions melting points and plasticity variation law. The reasonable inclusions plasticity controlling area is found out in low melting point. The melting point is up to 12.0℃ While MgO weight concentration is 10% in CaO-SiO2.Al2.3.MgO system, SiO2. Al2.3.and CaO in inclusions are in weight concentration range of 50-70%, 10-2.% and 10-40%, respectively. For purpose of gaining low melting point inclusions, silicon alumina radio in deoxidant should be controlled between 2.5 for ultra-low carbon stainless steel refining in industry.

关键词： ZG06Cr13.i4Mo stainless steel low melting point inclusion thermodynamic calculation

A computer simulation of nucleation and growth of thin films

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 442-451页

作者： ZHENG Xiaoping1,ZHANG Peifeng2.HE Deyan2.LIU Jun2. MA Jiantai3.1. Key Laboratory of Opto-Electronic {3. and Intelligent Control, Ministry of Education, Lanzhou Jiaotong University, Lanzhou 73.070, china 2. {2. of Physical science and {3., Lanzhou University, Lanzhou 73.000, china 3. {2. of Chemistry and Chemistry Engineering, Lanzhou University, Lanzhou 73.000, china 1. Key Laboratory of Opto-Electronic technology and Intelligent Control Ministry of Education Lanzhou Jiaotong University 730070 Lanzhou China 2. school of Physical science and {2. Lanzhou University 730000 Lanzhou China 3. school of Chemistry and Chemistry Engineering Lanzhou University 730000 Lanzhou China

A three-dimensional kinetic Monte Carlo technique has been developed for simulating the nucleation and growth of thin films. This model involves incident atom attachment, surface diffusion of the atoms on the growing surface and atom detachment from the growing surface. It takes some new effects into account, such as a significant improvement in calculation of activation energy for the atom diffusion, which renders the model more reasonable. In addition three optimum temperatures and the consistency of their dependence on deposition rate have been found out; the dependence of the surface roughness and relative density on the deposition rate has been discussed; and the approximation of freezing neighbour atoms and periodic boundary conditions has been applied.

关键词： Monte Carlo, thin film, nucleation, surface roughness, relative density.