检索结果-南通市图书馆

NON-POLLUTION PROCESS FOR COMPLEX REFRACTORY SILVER-GOLD ORES

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4期5卷 69-72,83页

作者： Xu, SM Zhang, CF Zhao, TC Li, zg CENT S UNIV TECHNOL DEPT NONFERROUS METCHANGSHA 410083PEOPLES R CHINA

ＮＯＮ－ＰＯＬＬＵＴＩＯＮＰＲＯＣＥＳＳＦＯＲＣＯＭＰＬＥＸＲＥＦＲＡＣＴＯＲＹＳＩＬＶＥＲ－ＧＯＬＤＯＲＥＳＸｕＳｈｅｎｇｍｉｎｇ；ＺｈａｎｇＣｈｕａｎｆｕ；ＬｉＺｕｏｇａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＮｏｎｆｅｒ... 详细信息

ＮＯＮ－ＰＯＬＬＵＴＩＯＮＰＲＯＣＥＳＳＦＯＲＣＯＭＰＬＥＸＲＥＦＲＡＣＴＯＲＹＳＩＬＶＥＲ－ＧＯＬＤＯＲＥＳＸｕＳｈｅｎｇｍｉｎｇ；ＺｈａｎｇＣｈｕａｎｆｕ；ＬｉＺｕｏｇａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＮｏｎｆｅｒｒｏｕｓＭｅｔａｌｌｕｒｇｙ，Ｃｅ...

关键词： complex ore carbonaceous substances silver-gold concentratem lime roasting

Cyclic Saturation Dislocation Pattern Observation in the Vicinity of Grain Boundaries by Electron Channeling Contrast 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3期14卷 211-214页

作者： Zhang, ZF Li, XW Su, HH Wang, zg Acad Sinica Inst Met Res State Key Lab Fatigue & Fracture Mat Shenyang 110015 Peoples R China

The cyclic saturation dislocation patterns within grains and in the vicinity of low-angle grain boundaries in fatigued copper crystal were successfully observed by electron channeling contrast technique in SEM. The results show that the dislocation patterns within grains consisted of typical two-phase structure, i.e. persistent slip bands (PSB) and veins. With increasing plastic strain amplitude (gamma(pl) greater than or equal to 1.7 x 10(-3)), large amount of PSBs and regular dislocation walls were observed. The dislocation walls and PSBs could cross through the low-angle grain boundaries continuously except that the dislocation-free zone (DFZs) appeared at some local regions. Combining with the cyclic stress-strain response and dislocation patterns, the effect of low-angle grain boundaries on cyclic deformation behavior was discussed.

关键词： Copper

Urine products of bone breakdown as markers of bone resorption and clinical usefulness of urinary hydroxyproline:an overview

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2004年第2期17卷 291-295页

作者： Baris Simsek zgülKaracaer inci Karaca Department of Oral and Maxillofacial Surgery Faculty of Dentistry University of Gazi Emek Ankara TurkeyDepartment of Oral and Maxillofacial Surgery Faculty of Dentistry University of Gazi Emek Ankara TurkeyDepartment of Prosthodontics Faculty of Dentistry University of Gazi Emek Ankara Turkey

Purpose The purpose of this study is to review the urine products of bone breakdown as markers of bone resorption and usefulness of urinary hydroxyproline.Data Related researches published in 1985 -2000 were systematically reviewed.Results Bone markers could be used for early diagnosis of bone metabolic diseases. Biochemical markers of bone resorption that reflect osteoclast activity and/or collagen degradation provide a new and potentially important clinical tool for the assessment and monitoring of bone metabolism. Assessment of bone resorption can be achieved with measurement of urinary hydroxylysine glycosides, urinary excretion of the collagen pyridinium cross-links, urinary excretion of type I collagen telopeptide breakdown products (cross-linked telopeptides) and urinary hydroxyproline.Conclusion Urinary hydroxyproline has been in use as a marker of bone resorption, but it lacks sensitivity and specificity. It is a modified aminoacid that is a metabolic product of collagen breakdown. Hydroxyproline may be released either free or with fragments of the collagen molecule attached during bone resorption, and it is also liberated by the breakdown of complement and nonskeletal collagen.

关键词： bone resorption marker biochemical markers hydroxyproline collagen breakdown hydroxylysine glycosides pyrolidine deoxypyrolidine N-tebpeptides C-telopeptides

Consolidation and Compression Property of Nanocrystalline NiAl Synthesized by Mechanical Alloying

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1996年第1期12卷 7-10页

作者： Liu, zg Guo, JT Shi, NL Hu, ZQ State Key Lab. for RSA Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The mixture of pure nickel and aluminum powders in the composition of Ni50Al50 was subjected to high energy ball milling. The high energy ball milling to 30 h resulted in the formation of a nanocrystalline NiAl with a grain size of about 10 nm. The as-milled NiAl powder was hot-pressed and the compact with a density of 90% was obtained. It was showed that heating to 900 degrees C and holding for more than 2 h failed to induce the coarsening of the fine nanocrystal in the material, the tendency of grain growth was weak. Compression testing showed that the compression ductility at room temperature reached about 7%. The ductility increased with the experimental temperature while the strength decreased drastically at elevated temperature.

关键词： Nickel alloys

Composite impact vector control based on Apollo descent guidance

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第7期35卷 67-74页

作者： Koray S.ERER Raziye TEKIN MKemal OzgOREN Tactical Missile Systems Roketsan Missiles Inc.Elmadağ06780Turkey Department of Mechanical Engineering Middle East Technical UniversityÇankaya 06800Turkey

A new three-dimensional missile guidance law to control the impact vector against a stationary target is *** composite guidance law has two well-known components:Apollo descent guidance and trajectory shaping *** respectively linear and planar guidance laws are combined to achieve a specified impact *** main idea is to define an impact plane and to steer the missile onto this plane using Apollo descent guidance while concurrently performing trajectory shaping with reference to the impact *** resulting guidance law is expressed by a single equation in vector form,which is straightforward to *** it originates from an optimal formulation,the performance of the proposed technique is expected to be *** is confirmed by comparative simulation runs,which also involve the method known as generalized explicit guidance.

关键词： Impact angle Impact plane Impact vector Three-dimensional missile guidance Trajectory shaping

Photoluminescence of ZnS Clusters in Zeolite-Y

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1997年第5期13卷 397-404页

作者： Chen, W Wang, zg Lin, ZJ Xu, Y Lin, LY Lab. of Semiconductor Materials Sciences Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China

Two obvious emissions are observed from the ZnS clusters encapsulated in zeolite-Y. The emission around 355 nm is sharp and weak, locating at the onset of the absorption edge. The band around 535 nm is broad, strong and Stokes-shifted. Both the two emissions shift to blue and their intensities firstly increase then decrease as the loading of ZnS in zeolite-Y or clusters size decreases. Through investigation, the former is attributed to the excitonic fluorescence, and the latter to the trapped luminescence from surface states. The cluster size-dependence of the luminescence may be explained qualitatively by considering both the carrier recombination and the nonradiative recombination rates. Four peaks appearing in the excitation spectra are assigned to the transitions of 1S-1S, 1S-1P, 1S-1D and surface state, respectively. The excitation spectra of the clusters do not coincide with their absorption spectra. The states splitted by quantum-size confinement are detected in the excitation spectra, but could not be differentiated in the optical absorption spectra due to inhomogeneous broadening. The size-dependence of the excitation spectra is similar to that of the absorption spectra. Both the excitation spectra of excitonic and of trapped emissions are similar, but change in relative intensity and shift in position are observed.

关键词： Zeolites

Cyclic Deformation and Fatigue Damage Behavior of Cu Monocrystals, Bicrystals and Tricrystals

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1999年第6期15卷 489-508页

作者： Wang, zg Li, XW Zhang, ZF Jia, WP Li, SX Chinese Acad Sci Inst Met Res State Key Lab Fatigue & Fracture Mat Shenyang 110015 Peoples R China

In the present work, the cyclic deformation behavior of Cu single crystals oriented for double- and multiple slip as well as Cu bicrystals and tricrystals was investigated under constant plastic strain control at room temperature in air. The main objectives of the study are: (1) to find out the effects of crystallographic orientation and grain boundary (GB) on the cyclic stress-strain (CSS) curves; (2) to compare the cyclic deformation behavior of the double-, multiple-slip crystals, bicrystals and tricrystals with that of single-slip oriented crystals and to correlate the results with those of polycrystals; (3) to examine the corresponding dislocation structures; (4) to investigate the interactions of persistent slip bands (PSBs) with GBs and triple joint (TJ) as well as intergranular fatigue cracking in Cu bicrystals and tricrystals.

关键词： Crystals

Brief Review and Reconsideration of Fatigue Crack Closure Effect in Materials

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1997年第1期13卷 1-14页

作者： Chen, DL Weiss, B Stickler, R Wang, zg ACAD SINICA INST MET RESSTATE KEY LAB FATIGUE & FRACTURE MATSHENYANG 110015PEOPLES R CHINA UNIV VIENNA INST PHYS CHEM MAT SCIA-1090 VIENNAAUSTRIA

The state-of-the-art of fatigue crack closure effect, involving the mechanisms, measurements, models, evaluation methods, influencing factors and existing problems is briefly reviewed. Attention is concentrated on a new consideration of closure effect and a re-definition of the effective driving force for the propagation of a fatigue crack. A theoretical basis for measuring the closure effect is established. The proposed closure concept takes into account the role of the tower portion of loading cycle below the opening load. The conventional closure concept is proven to be correct only for some extreme cases which are practically non-existent for engineering materials. A miniature strain gauge technique is developed to measure the crack closure. Stress-ratio-change tests at threshold level clearly indicate the shortcomings of the conventional closure concept, and the validity of the newly-proposed closure concept. The application of the proposed concept can give rise to a new method for the determination of the effective fatigue threshold of materials. If the fatigue threshold is measured at a sufficiently negative stress ratio (R

关键词： FINITE-WIDTH STRESS-RATIO THRESHOLD GROWTH LOAD PLATE

STM Study on the Surface Relief and Mechanism of Bainite Transformation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1996年第4期12卷 249-254页

作者： Yang, zg Fang, HS Wang, JJ Zheng, YK Li, CM Dept. of Materials Science and Engineering Tsinghua University Beijing 100084 China

Scanning tunneling microscopy (STM) has been first employed to study the surface relief accompanying bainite transformation in a Fe-2.17C-12.18Cr-0.31Si-0.26Mn (wt pct) steel. With the exclusive vertical resolution of STM, we observed that the surface relief associated with bainite is a group of surface reliefs related to subplates, subunits and sub-subunits. As a whole, the relief group is in a tent shape, not of invariant plane strain (IPS) type, which is obviously different from that of martensite, and implying that bainite is not formed by shear mechanism. The fine structure of bainite in Fe-1.0C-4Cr-2.0Si (wt pct) alloy has also been studied with STM and TEM. It is found that the bainite plate is composed of subplates, subunits and sub-subunits. On the basis of the fine structure inside a bainitic ferrite plate observed under STM, a sympathetic-ledgewise mechanism of bainite formation is proposed.

关键词： Steel