检索结果-南通市图书馆

Relationship between Low Temperature Toughness and Microstructure in Low Activation Fe-Cr-Mn(W,V)Steel for Fusion Reactors

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 111-115页

作者： Benfu Hu Chengchang jia(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

Fe-Cr-Mn (W, V) austenite steel was researched in order to supply a theory base for the first wall materials of fusion *** included vacuum melting, forging, annealing, solution treatment, Charpy impact tests and microstructure observation. Theresults show that the imped value decreases with the test temperature decreasing. In this system, there is ductile/brittle transition. Themechanism of this decrease of the impact value is considered to be due to γ - ε transformation in sub-stable austenite steel and stoppingoverlapping sacking fault by grain boundaries in stable austenite steel.

关键词： fusion reactor first wall materials low temperature toughness Fe-Cr-Mn system

DISTRIBUTION AND EFFECT OF Ce IN RE BEARING DUCTILE IRON

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1992年第6期5卷 419-424页

作者： ZHU Ruihui WANG Yu HAN Qiyong SONG Weixi university of Science and technology beijing,beijing,China Engineer,Institute of Precise and Special New Materials,university of Science and technology beijing,beijing 100083.China beijing Univ of Science and Technology Beijing China

The dependence of nodularization of graphite upon Ce content in RE bearing nodular cast iron,prepared by directional solidification,has been investigated by electrolytic extraction-radioisotope assay analysis of Ce in each phase of the iron together with measurement of nodulized *** show that the Ce occurs mainly as alloyed form. In the graphite phase,the Ce content is believed to be characterization of *** graphite would completely nodulized only the Ce is over a certain content in graphite phase.

关键词： RE nodular cast iron directional solidification graphite Ce

Scenario simulation and forecast of land use/cover in northern China

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2008年第9期53卷 1401-1412页

作者： LI YueChen 1,2,3.& HE ChunYang 3.1 College of Geographical Science, Chongqing Normal university, Chongqing 400047, China 2 College of Resources and Environmental Science, Chongqing university, Chongqing 400044, China 3.College of Resources Science & technology, {3. Normal university, {3. 100875, China College of Geographical Science Chongqing Normal University Chongqing 400047 China College of Resources and Environmental Science Chongqing University Chongqing 400044 China College of Resources Science & technology Beijing Normal University Beijing 100875 China

Modeling land use/cover scenario changes and its potential impacts on structure and functions of ecosystem in typical regions are helpful to understanding the interactive mechanism between land use/cover system and ecosystem. Based on the analysis of the existing land use/cover simulation and forecast models, a land use/cover scenario dynamics model by the integration of System Dynamics (SD) model, Back Propagation Neural Network (BPNN) and Cellular Automata (CA) model is developed with land use/cover scenario changes in northern China in the next 3. years and simulated in this paper. The model is to simulate the land use/cover scenario demands by using a SD model at first, and then allocating the land use scenario patterns at the local scale with the considerations of land use/cover suitability, inheritance ability and neighborhood effect by using BPNN-CA model to satisfy the balance between land use/cover scenario demands and supplies. It integrates the advantages of SD, BPNN and CA. Macro-driving factors and the micro-spatial pattern are also fully taken into account. The BPNN simplifies the identification of the factors’ weights used in CA model and improves the reliability of the simulation results. The simulation accuracy of the model developed in this paper was found to be about 74%. It suggests that the model has the ability to reflect the complexity of land use/cover system at different scales to some extent and it is a useful tool for assessing the potential impacts of land use system on ecosystem. The simulated results also indicate that the urban land, water area and forest will increase significantly, and farmland and unable land will decrease gradually. Obvious land use/cover changes will take place in the farming-pastoral zone and the southeast area of northern China.

关键词：土地利用中国北方细胞自动机系统动力学

A cross-monotonic cost sharing method for the facility location game with service installation costs

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2009年第11期52卷 2530-2536页

作者： XU DaChuan Department of Applied Mathematics,beijing university of technology,beijing 100124,China 1. Department of Applied Mathematics Beijing University of Technology Beijing 100124 China

In this paper,we consider the metric uncapacitated facility location game with service installation costs. Our main result is an 11-approximate cross-monotonic cost-sharing method under the assumption that the install... 详细信息

关键词： facility location game cross-monotonic cost-sharing method linear programming relaxation 90C27 91A12

Fabrication of Grain-oriented (Bi,Pb)_2Sr_2Ca_2Cu_3._x Superconducting Tapes Using Magnetic Field and Vibration Technique

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 1998年第1期14卷 86-88页

作者： Yanwei MA and Xianjin WANG (Dept. of Metal Forming, university of Science and technology beijing, beijing 100083. China)Zutang WANG (Tsinghua university, beijing 100084, China) Univ Sci & Technol beijing Dept Met Forming Beijing 100083 Peoples R China Tsing Hua Univ Beijing 100084 Peoples R China

Highly textured (Bi,Pb)2Sr2Ca2Cu3.x superconducting tapes have been fabricated by means of magnetic-field and vibration technique. This method is an effective way of improving the degree of grain alignment and density of oxide core in tapes after heat treatment and pressing *** of above 20% was increased than that without treatment.

关键词： Bi,Pb Pb Sr Fabrication of Grain-oriented x Superconducting Tapes Using Magnetic Field and Vibration Technique Ca Cu

An improvement to the data processing course of electrochemical impedance technique

在线全文

学校读者我要写书评

暂无评论

Journal of university of Science and technology beijing 2003年第6期10卷 57-60页

作者： Yinglv Jiang, Yinshun Wu, and Hong ChuCorrosion and Protection Center, university of Science and technology beijing, beijing 100083. China Corrosion and Protection Ctr. Univ. of Sci. and Technol. Beijing Beijing 100083 China

For some electrochemical systems the traditional data processing methods cannot be met, so it is necessary to develop a new method to deal with these problems. When processingthe electrochemical AC impedance data of titanium alloy TA12 in 3.percent NaCl solution (at freecorrosion potential, room temperature) a new method is developed which can detach the information ofthe interface resistance demonstrably from the interface capacitance. The results show that theinterface resistance and capacitance are all functions of frequency. And the AC impedance of theresistance and capacitance obey the following relations: C(f) = 10^(4.01982) f^(-0.9292), R(f)=10^(4.80011) (f+0.008)^(-0.90897), which is completely different from the traditional conceptionthat the interface resistance and capacitance are constants. And this phenomenon is ubiquitous intitanium alloys according to the study. So perhaps it is an innate characteristic of interface.

关键词： titanium alloy electrochemical impedance corrosion

Calculating Model of Mass Action Concentrations for Fe-Cr-P Melts and Optimization of Thermodynamic Parameters

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 11-14页

作者： Jian Zhang (Metallurgy School, university of Science and technology Beliing, beijing 100083. China) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

According to the results of research on the thermodynamic propelles of Fe-Cr, Fe-P and Cr-P melts, the measured achvihes of Fe-Cr-P melts from reference sources as well as the coexistence theory of metallic melts structure involving compound formation, a calculating model of the mass action concentrations for Fe-Cr-P melts has been formulated and some of its thermodynamic parameters have been optimized. The calculated mass action concentrations agree with the measured achvities, which shows that this model can reflect the structural reality of Fe-Cr-P melts.

关键词： activity dephosphorization of stainless steel, coexistence theory mass action concentration

Molecular and quantum mechanical studies on the monomer recognition of a highly-regular β-helical antifreeze protein

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2004年第1期47卷 34-40页

作者： YANG Zuoyin, JIA Zongchao, LIU Ruozhuang & CHEN GuangjuDepartment of Chemistry, beijing Normal university, beijing 100875, China Faculty of Science, beijing university of Chemical technology, beijing 100029, China Department of Biochemistry, Queen’s university, Kingston, Ontario K7L 3.6, Canada 1. Department of Chemistry Beijing Normal University 100875 Beijing China 2. Faculty of Science Beijing University of Chemical Technology 100029 Beijing China 3. Department of Biochemistry Queen? University K7L 3N6 Kingston Ontario Canada

The possible interaction models for an antifreeze protein from Tenebrio molitar (TmAFP) have been systematically studied using the methods of molecular mechanics, molecular dynamics and quantum chemistry. It is hoped that these approaches would provide insights into the nature of interaction between protein monomers through sampling a number of interaction possibilities and evaluating their interaction energies between two monomers in the course of recognition. The results derived from the molecular mechanics indicate that monomer? β-sheets would be involved in interaction area and the side chains on two p-faces can match each other at the two-dimensional level. The results from molecular mechanics and ONIOM methods show that the strongest interaction energy could be gained through the formation of H-bonds when the twoβ-sheets are involved in the interaction model. Furthermore, the calculation of DFT and analysis of van der Waals bond charge density confirm further that recognition between the two TCTs mainly depends on inter-molecular hydroxyls. Therefore, our results demonstrate that during the course of interaction the most favorable association of TmAFPs is via their β-sheets.

关键词： antifreeze protein, recognition, dynamics simulation, molecular mechanics, quantum chemistry.

Mass transfer coefficients in metallurgical reactors

在线全文

学校读者我要写书评

暂无评论

Journal of university of Science and technology beijing 2003年第2期10卷 1-9页

作者： Ying QuMetallurgical Engineering School, university of Science and technology beijing, beijing 100083. China Univ Sci & Technol beijing Met Engn Sch Beijing 100083 Peoples R China

An overview on the application and achievements of physico-mathematicalmodeling of metallurgical processes in China is briefly declared. The important role of coefficientsin model formulation is shown from our experience. The mass transfer coefficients of the slag-metalreactions and the gas-metal reactions are discussed referring to the flow conditions near theinterface. The influence of the surface-active species on the mass transfer and the interfacialreaction is also discussed briefly.

关键词： mass transfer modeling pyrometallurgy reaction engineering interfacial flow stirring power