检索结果-南通市图书馆

High Resolution Electron Microscopy Observations of Structural Changes in Iron Nitride Films Annealed in Vacuum

Journal of materials science & technology 1997年第2期13卷 123-126页

作者： Shengkai GONG Huibin XU (Dept. of materials science and engineering, beijing university of Aeronautics and Astronautics, beijing 100083. china) Dept. of materials science and engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

Iron-nitride films were prepared by reactive sputtering, and the effect of annealing treatment on the structures was investigated by means of in-situ electron microscopy and high resolution electron microscopy (HREM). As-deposited films were observed to be a mixed structure of a few ultrafine epsilon-Fe2-3N particles existing in the amorphous matrix. it was found that the structure-relaxation in the amorphous occurred at 473 K, and the ultrafine grains began to grow at the higher annealing temperatures. The transition of the amorphous to epsilon-Fe2-3N was almost completed at 673 K. It is considered that the formation of the ideal epsilon-Fe3N is originated from the ordering of the nitrogen atoms during the annealing in vacuum. On the other hand, gamma'-phase (Fe4N) was seen to precipitation of epsilon-phase at 723 K. Two possible modes are proposed in the precipitation of gamma'-phase, depending on the heating rate and crystallographic orientation relationships, i.e. [121](epsilon)//[001](gamma), (2(1) over bar0$)(epsilon)//(110)(gamma) and [100](epsilon)//[110](gamma), (001)(epsilon)//(111)(gamma). In addition, alpha-Fe particles were observed to form from the gamma'-phase at high temperatures. We assumed that these structural changes are due to the diffusion of nitrogen and iron atoms during the annealing, except for the case of the precipitation of the gamma'-phase as depicted above. The results obtained in this work are in a good agreement with the assumption.

关键词： Figure High Resolution Electron Microscopy Observations of Structural Changes in Iron Nitride Films Annealed in Vacuum

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Prediction of Enthalpies of Fusion for Divalent Rare Earth Halides Based on Modeling by Artificial Neural Networks and Pattern Recognition

引用

International Journal of Minerals,Metallurgy and materials 1999年第1期13卷 24-26页

作者： Yimin Sun Zhiyu Qiao Minghong He(Applied science School, university of science & technology beijing, beijing 100083. china)(National Natural science Foundation of china, beijing 100083. china) Applied science School University of Science and Technology Beijing Beijing 100083 China National Natural science Foundation of china Beijing 100083 China

The artificial neural network (ANN) and the pattern recognition were applied to study the correlation of enthalpies of fusion for divalent rare earth halides with their microstructural parameters,such as ionic radius and electronegativity. The model,represented by a back-propagation netal network, was trained with a 12 set of published data for divalent rare earth halides and then was used to predict the unknown ones. Also the criterion equations were ptesented to determine the enthalpies of fuSion for divalent rare earth halides using pattern recognition in mis work. The results from the model in ANN and criterion equations are in very good agreement with reference data.

关键词： BP neural network pattern recognition enthalpy of fusion divalent rare earth halides microstructural parameters

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Sticking-up Behaviors and Surface Friction of IF Electrogalvanized Sheet Steel in Forming

引用

International Journal of Minerals,Metallurgy and materials 1999年第1期13卷 61-63,68页

作者： Jiming Hu Jixun Wu Yanping Lu Yanrong Zhu (Material science and engineering School, university of science and technology beijing, beijing 100083. china) Univ of science and technology Beijing Beijing China

X-ray diffraction (XRD), ball-disc friction and wearing machine and draw-bead test were introduced to investigat the strcusture and workability of IF sheet steel electrogalvanized deposits prepared from sulphate solution system. It was shown that the picking-up of the zinc coating on die strengthened with the increasing of friction factor which was originally affected by the coating's structure. Duing forming, (00X) planes (X= 2, 4) preferential orientation of zinc deposits increased, which resulted in enhanc ing the coating's friction behaviors. Therefore, the forming mechanism of electrogalvedzed deposit was demonstrated that both friction and the stricking -up behaviors of the coating are intensified simultaneously and affect each other.

关键词： electrogalvanized deposit forming friction factor

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The influence of thermal radiation on MHD station-point flow past a stretching sheet with heat generation

引用

Acta Mechanica Sinica 2011年第4期27卷 502-509页

作者： Jing Zhu.Lian-Cun Zheng.Xin-Xin Zhang Department of Mathematics and Mechanics,university of science and technology beijing,100083.beijing,china Thermal engineering Department,university of science and technology beijing,100083.beijing,china Zheng Department of Mathematics and Mechanics University of Science and Technology Beijing Beijing China Thermal engineering Department University of Science and Technology Beijing Beijing China

This letter is concerned with the plane and axisymmetric stagnation-point flows and heat transfer of an electrically-conducting fluid past a stretching sheet in the presence of the thermal radiation and heat generation or absorption. The analytical solutions for the velocity distribution and dimensionless temperature profiles are obtained for the various values of the ratio of free stream velocity and stretching velocity, heat source parameter, Prandtl number, thermal radiation parameter, the suction and injection velocity parameter and magnetic parameter and dimensionality index in the series form with the help of homotopy analysis method （HAM）. Convergence of the series is explicitly dis- cussed. In addition, shear stress and heat flux at the surface are calculated.

关键词： Thermal radiation MHD Laminar boundarylayers - Homotopy analysis method

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Fuzzy Model for Evaluating the Mining Condition of Underground Coal Mines

引用

International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 242-245页

作者： Zhongrue Li Shaowen Zhang(Resources engineering School, university of science and technology beijing, Beding 100083. china) Resources engineering School University of Science and Technology Beijing Beijing 100083 China

In mining industries no mines are identical and each mine has its own unique set of mining conditions. In order to study thecondition of mines for efficiency, safety and economy reasons, a fuzzy model is presented based on fuzzy evaluation. Relevant data fromfive mines were collected and the model was used to evaluate the mining condition of these mines. The evaluation results are in conformity with the real situation.

关键词： fuzzy model mining condition coal mine

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Recycling of Spent Nickel-Cadmium Batteries

引用

International Journal of Minerals,Metallurgy and materials 2000年第2期14卷 126-131页

作者： Xanghua Kong Pingnan Wu(Metallurgy School, university of science and technology beijing, beijing 100083. china) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

A technique for recycling spent nickel-cadmium batteries, which makes separaion of cadmium and nickel possible, is developed by laboratory-scale experiments. NH3-H2CO3 aqueous solution was used in this leaching technique. Since neutralization and/or solvent extraction were not required in the separation procedure of nickel and cadmium, the closed systemizaion of the process becomespossible. Experimental results show that, (1) if the NH3 concentraion of leaching solution is sufficiently high and the ratio of H2CO3 toNH3 is properly adjusted, both Ni(OH)2 and Cd(OH)2 react with NH, and quickly dissolve into leaching solution, and (2) Ni(OH)2 can beconverted into insoluble NiO by calcination at 500℃, and CdO from Cd(OH)2 by calcination maintains good solubility in NH3-H2CO3aqueous solution. As a conclusion, the recycling technique characterized by two step leaching can be developed based on such changesin dissolution behavior by calcination. Meanwhile, the yields of 99.8% for nickel and 97.6% for cadmium are obtained, and the puritiesof Recycling of Spent Nickel-Cadmium BatterieRecycling of Spent Nickel-Cadmium Batteries Recycling of Spent Nickel-Cadmium Batteriesrecovered nickel and cadmium are 99.9% and 98.6%, respectively.

关键词： nickel-cadmium batteries recycling, ammonia leaching closed system environmental protection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microstructures of Sintered Mo-Cu Alloys with Mechanically Activated Powder

引用

Rare Metals 2001年第2期20卷 112-116页

作者： Chengchang Jia, Zhong He, Xuekuan Su, Ziqin Yang, Jun Zhao, Zizhang Xie (School of materials science and engineering, university of science and technology beijing, beijing 100083. china Beliing Polytechnic university, beijing 100022, beijing) 北京科技大学北京 100083 北京工业大学北京 100022

Mechanical activation and liquid phase sintering were used to manufacture high performance Mo-Cu alloy and develop new processes. The microstructures and properties of the alloy were investigated. The experimental results showed that: (1) the ball milled Mo/Cu powder has lamellar structure, (2) the microstructures of the sintered Mo-Cu alloy were homogenous compound structures of adhesive phase Cu linking Mo grains, (3) Mo grains frequently strung or gathered in Cu phase, and (4) the full densities of Mo-Cu alloy was achieved through sintering and special densification process. As a result, the properties of the alloy are good enough to satisfy various requirements.

关键词： Mo-Cu alloy powder metallurgy mechanical activation microstructure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of Surface-Active Elements Sulfur on Flow Patterns of Welding Pool

引用

Journal of materials science & technology 2005年第3期21卷 408-414页

作者： Yuzhen ZHAO, Yongping LEI and Yaowu SHI School of materials science and engineering, beijing university of technology, beijing 100022, china School of materials science and engineering Beijing University of Technology Beijing 100022 China

A 3D mathematical model is developed to calculate the temperature and velocity distributions in a moving gas tungsten arc (GTA) welding pool with different sulfur concentrations. It has been shown that, the weld penetration increases sharply with increasing sulfur content. When sulfur content increases beyond 80 × 10-6, the increase in sulfur content does not have an appreciable difference on the welding pool size and shape, and the depth/width remains constant. Sulfur changes the temperature dependence of surface tension coefficient from a negative value to a positive value and causes significant changes on flow patterns. The increase in soluble sulfur content and the decrease at free surface temperature can extend the region of positive surface tension coefficient. As sulfur content exceeds 125×10-6, the sign of surface tension coefficient is positive. Depending upon the sulfur concentrations, three, one or two vortexes that have different positions, strength and directions may be found in the welding pool. The contrary vortexes can efficiently transfer the thermal energy from the arc, creating a deep welding pool. An optimum range of sulfur content is 20-150×10-6.

关键词： Surface-active elements Sulfur Plow patterns Depth/width

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Special Orientation Relationships Observed at the Early Stages of Recrystallization in Pure AlMn Alloy

引用

International Journal of Minerals,Metallurgy and materials 1998年第3期12卷 140-146页

作者： Ping Yang(Material science and engineering School, university of science and technology beijing, beijing 100083. china)(Institute for Metal science and Metal Physics, Aachen university of technology, D-52056, Aachen, Germany) Material science and engineering School University of Science and Technology Beijing Beijing 100083 China Institute for Metal science and Metal Physics Aachen University of Technology D-52056 Aachen Germany

Electron Back Scattering Diffraction (EBSD) technique in a SEM was used to obtain local orientationalinformation on new grains and their surrounding deformed matrices at the early stages of recrystallization in pureA1-1 .3%Mn alloy. Results show that special orientation relationships including twin-relationship often exist betweennew grains, between new grains and deformed grains or between deformed grains. The occurrence of such specialorientation relationships is attributed to the special deformation behavior in the samples with large initial grain *** formation of recrystallization twins is discussed in a different way to those of traditional ones.

关键词： Orientation relationship recrystallization AlMn, EBSD

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Hydrogen on Dezincification Layer-Induced Stress

引用

Journal of materials science & technology 2003年第3期19卷 287-288页

作者： Wuyang CHU, Kewei GAO, Yapin LIU Lijie QIAODepartment of materials Physics, university of science and technology beijing, beijing 100083. china Dept. of Mat. Phys. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The effect of hydrogen on the dezincification layer-induced stress and the susceptibility to SCC was investigated. Experimental results showed that the dezincification layer-induced stress increased with increasing hydrogen concentration, and 3x10-6 hydrogen could increase the susceptibility to SCC of brass in ammonia solution by 10%.

关键词： Brass Dezincification layer-induced stress Susceptibility to SCC Hydrogen

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：