检索结果-南通市图书馆

3D Modeling Quantitative Evaluation for the Underground Space Resources in beijing City

在线全文

学校读者我要写书评

暂无评论

地学前缘 2009年第S1期16卷 283-284页

作者： Yi Tian,Jianping Chen,Limei Wang School of Land Resources and Technology,China University of Geosciences(beijing),beijing 100083,China.

Recently,underground space evaluation has become fundamental for a city’s long term sustainable development *** paper,based on the 3D-GIS tools,adopts"multi-factors comprehensive evaluation"models to establish a prac... 详细信息

关键词： city underground space resources quantitative evaluation 3D modeling

MECHANISMS AND PREDICTION OF FRACTURE TOUGHNESS ANISOTROPY OF HIGH STRENGTH Al ALLOYS

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5期5卷 324-329页

作者： LI Huanxi CHEN Changqi beijing University of Aeronautics and Astronautics,beijing,China beijing Univ of Aeronautics and Astronautics Beijing China

Contributions of weak grain boundary,cracking path deflection and grain boundary delamination to fracture toughness anisotropy of high strength Al alloys were evaluated based upon approaches of fracture mechanics in conjunction with physical cracking mechanisms. The predicted results are close to those experimentally determined in the literature and in this *** strong anisotropy of fracture toughness of high strength Al alloys is therefore attri- buted mainly to weak grain boundary cracking,cracking path deflection and grain boundary *** the methods of this work,short-transverse fracture toughness values of some semi-products can he estimated from in-plane toughness values and corresponding frac- ture characteristics when it is difficult to be determined experimentally.

关键词： Al alloy fracture toughness anisotropy

Interannual variation of annual precipitation and urban effect on precipitation in the beijing region

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9期17卷 1042-1050页

作者： Yu Shuqiu(State Key Laboratory on Severe Weather,Chinese Academy of Meteorological Sciences,beijing 100081,China) State Key Laboratory on Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081， China

The large scale character of the interannual variation of precipitation and the urban effect on local annual precipitation anomaly are investigated in this paper based on the 1960-2000 annual precipitation observations at 20 stations in the beijing *** results show that:the annual precipitation in the beijing region possesses the large scale variation character with the linear trend of-1.197/10 yr,which corresponds to a total reduction of 27.82 mm in annual precipitation in the 41 years;the local annual precipitation anomalies(percent of the normal 1960-2000)show a positive center near the urban area,*** precipitation island(UPI),whose intensity increases with the linear trend of 0.6621%/10 yr,opposite to the interannual trend of large scale precipitation over the beijing region;changes in the UPI are also associated with the intensity of synoptic processes of precipitation,and when the synoptic processes are strong(wet years),the intensity of UPI strengthens,while the synoptic processes are weak(dry years),and the UPI disappears in the beijing region.

关键词： urban precipitation island effect interannual climate variation precipitation beijing atmospheric science

A Back Look on the Binary Phase Diagrams of Metals from the Mass Action Law and the Coexistence Theory of Metallic Melts

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of University of Science and Technology beijing 2001年第1期8卷 15-19页

作者： Jian Zhang Metallurgy School, University of Science and Technology beijing, beijing 100083, China Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China

According to the mass action law and the coexistence theory of metallic melts, the mass action concentrations of Cu-Mg, Bi-Tl and Ni-Al melts involving compound formation have been calculated. The calculated results show that, except the ultimate case of pure element, when two elements are present in the melts, all structural units (atoms and molecules) without exception will be present in the melts, i.e., their concentrations may change from great to small, but they will not vanish into nothing, and only under such conditions, the calculated results both agree with practice and obey the law of mass action. In view of that over considerable wide composition range, the activities of both elements of the three solid binary alloys mentioned above have been measured, this seems in contradiction with the present relevant phase diagrams, in which the structural units are determined by composition range, so the latter needs further investigation and consideration.

关键词： activity phase diagram the mass action law the coexistence theory

Microstructural Features During Strain Induced Ferrite Transformation in 08 and 20Mn Steels

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 2001年第2期8卷 105-110页

作者： Ping Yang, Feng-e Cui, Fuming Wang (Materials Science and Engineering School, University of Science and Technology beijing, beijing 100083, China) (Metallurgy School, University of Science and Technology beijing, beijing 100083, China) Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China

The microstructure evolution during strain induced ferrite transformation was followed in thermal-simulation tests of clean 08 and 20Mn steels. The influences of carbon equivalence and initial austenite grain size on ferrite grain refinement and the volume fraction of ferrite during straining were inspected. The results revealed that the accelerating effect of ferrite transformation by strain was increased as the carbon equivalence decreased. However, finer ferrite grains were obtained at higher carbon content. At strain of similar to1.5 ferrite grains less than 3 mum and 2 mum can be obtained in 08 and 20Mn steels respectively. Whereas the ferrite grain refinement in 08 steel was due to both effects of strain induced transformation and ferrite dynamic recrystallization, that in 20Mn was mainly due to strain induced transformation. Heavy strain can produce fine ferrite grains in coarse austenite grained 08 steel, but it would lead to band microstructure in coarse austenite grained 20Mn.

关键词： clean carbon steel strain induced transformation grain refinement ferrite dynamic recrystallization

EFFECT OF NITROGEN ON GRAPHITE MORPHOLOGY IN GRAY CAST IRON

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 151-155页

作者： ZHAI Qijie HU Hanqi University of Science and Technology beijing,beijing,China Faculty of Foundry,University of Science and Technology beijing,beijing 100083,China beijing Univ of Science and Technology Beijing China

The distribution of N and morphology of graphite in gray cast iron containing N were studicd by adopting the man-made specimens of Fe-C-Si-Mn alloys with some N added. The N adsorbed along the interfaces between graphite and matrix together with solid- solutioned in graphite is believed to be the principal cause of morpholongical variation of graphite.

关键词： gray cast iron graphite morphology N

Recycling of Spent Nickel-Cadmium Batteries

在线全文

学校读者我要写书评

暂无评论

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

Precipitatation Behavior of FeTiP Phase in High Strength IF Steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 197-203页

作者： Zisu Zhao, Weimin Mao, Yongning Yu (University of Science and Technology beijing, beijing 100083, China) University of Science and Technology beijing Beijing 100083 China

The influence of chemical composition and annealing parameters on the behavior of FeTiP precipitation has been investigated. With increasing Ti content the yield strength and tensile strength were reduced, and the tendency of FeTiP precipitation became more remarkable. No FeTiP precipitate was observed and the best mechanical properties have been obtained in the steel sheet, of which the atom ratio of Ti to N is approximately equal to 1. In the temperature range of 700 to 800℃ the FeTiP precipitation could appear easily. The precipitation process was suppressed when the annealing temperature was below 600℃, and the FeTiP phase was dissolved above 900℃. The FeTiP precipitates would inhibit the migration of grain boundaries during the recrystallization in certain extent, and weaken the density of {111} fiber texture, which resulted in the reduction of r value. The relationship between composition and processing parameters, as well as their influence on the mechanical properties is discussed.

关键词： IF steel FeTiP precipitation

INFLUENCE OF INITIAL TEXTRUE ON THE COLD ROLLING TEXTURE OF Ti SHEETS

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1995年第2期5卷 66-70页

作者： Mao, Weimin Yu, Yongning Li, Botao(University of Science and Technology beijing, 100083 beijing) Univ of Science and Technology Beijing Beijing China

ＩＮＦＬＵＥＮＣＥＯＦＩＮＩＴＩＡＬＴＥＸＴＲＵＥＯＮＴＨＥＣＯＬＤＲＯＬＬＩＮＧＴＥＸＴＵＲＥＯＦＴｉＳＨＥＥＴＳ￥Ｍａｏ，Ｗｅｉｍｉｎ；Ｙｕ，Ｙｏｎｇｎｉｎｇ；Ｌｉ，Ｂｏｔａｏ（ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎ... 详细信息

ＩＮＦＬＵＥＮＣＥＯＦＩＮＩＴＩＡＬＴＥＸＴＲＵＥＯＮＴＨＥＣＯＬＤＲＯＬＬＩＮＧＴＥＸＴＵＲＥＯＦＴｉＳＨＥＥＴＳ￥Ｍａｏ，Ｗｅｉｍｉｎ；Ｙｕ，Ｙｏｎｇｎｉｎｇ；Ｌｉ，Ｂｏｔａｏ（ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙＢｅ...

关键词： Ti Rolling Texture ODF