检索结果-南通市图书馆

维普期刊数据库博看期刊

Existence of periodic solutions for Lienard equations with finite delay

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第14期42卷 1145-1149页

作者： Wei, jj Huang, QC Department of Mathematics Northeast Normal University Changchun China

THE existence of periodic solutions of Lienard equation with finite delay x(t) + f(x(t))x(t) + g(x(t-r))=0 (1)has been studied extensively. However, most works we have so far require the assumption thatx·g(x)>0 for a... 详细信息

关键词： delay Lienard equations bifurcations periodic solutions.

Minerogenetic mechanism of Rushan gold deposit, Shandong Province——Evidence of ore-forming fluid and H, O, Sr isotopes

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第3期42卷 240-243页

作者： Zhai, JP Hu, K Lu, jj Department of Earth Sciences Nanjing University Nanjing 210093 China

THE Rushan gold deposit, being of quartz-vein type, is located in biotite monzonitic granite of Kunyushan complex pluton in eastern Shandong, China, and the orebody No. 2 is the largest mono-vein deposits found in China. The gold mineralization can be divided into three stages according to crisscross relations of the various microlodes in the deposit: Ⅰ. pre-ore stage of comb-structured milky-white quartz veins; Ⅱ. main mineralization stage of multi-metal sulphides and siderite-quartz veins; Ⅲ. post-ore stage of mottled cryptocrystalline quartz veins.

关键词： granite quartz-vein type gold deposit ore-forming fluid origin of deposit.

TWO　NEW　PHENYLPROPANOID　GLYCOSIDES　FROM　CARYOPTERIS　INCANA(THUNB.)MIQ

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1996年第5期7卷 445-448页

作者： Gao, jj Han, GQ Yang, L BEIJING MED UNIV NATL LAB NAT & BIOMIMET DRUGSBEIJING 100083PEOPLES R CHINA LANZHOU UNIV STATE KEY LAB APPL ORGAN CHEMLANZHOU 730000PEOPLES R CHINA

Abstract: Two new phenylpropanoid glycosides, incanosides A and B were determined as 3-hydroxy-4-methoxy-βphenylethyl α-L-rhamnopyranosyl(1→3)-β-D-glucopyranosyl(1→2)-6-O-feruloyl-β-D-glucopyranoside and 3-hydroxy-4-methoxy-β-phenylethyl α-L-rhanmopyranosyl (1→3)-β-D-ghucopyranosyl(1→2)-β-D-glucopyranoside, respectively.

关键词：

Study on a New Type of All-Solid-StateReference Electrode

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1996年第11期7卷 1019-1022页

作者： Huang, CL Ren, jj Xu, DF HEBEI MED UNIV DEPT PHARMSHIJIAZHUANG 050017PEOPLES R CHINA

A new type of all-solid-state Ag/AgCl reference electrode was constructed by using urea-formaldehyde resin as the frame material and KCl powder as the active component. The properties of the electrode were studied in detail. The electrode exhibited excellent characteristics and could be applied to the electrochemical measurements in syrupy, colloidal and higher temperature solutions as a reference electrode.

关键词： Study on a New Type of All-Solid-StateReference Electrode

Effect of anti-fibrosis compound on collagen expression of hepatic cells in experimental liver fibrosis of rats

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2000年第6期6卷 877-880页

作者： Wang LT Zhang B Chen jj Shanghai TCM Univ Shuguang Hosp Dept Hepatopathy Shanghai 200021 Peoples R China

INTRODUCTIONLiver fibrosis is mainly characterized by theexcessive synthesis and decreased degradation ofextracellular matrix(ECM),especially the synthesisand deposition of *** all kinds of cellsin the liver have part... 详细信息

关键词： liver cirrhosis collagen hepatic stellate cells immunohistochemistry antifibrosis complex prescription rats

A　Simple　New　Method　for　the　Fabrication　of　Carbon　Paste　Microelectrode　and　its　Characterization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1996年第11期7卷 1016-1018页

作者： Sun, jj Fang, HQ Chen, HY NANJING UNIV DEPT CHEM NANJING 210093 PEOPLES R CHINA

A procedure for preparing carbon paste microeletrodes is described. This procedureis based on incorporation of carbon paste into the microholes at the tips ofchemically etched microdisk electrodes. The electrodes combine the advantages ofmicrodisk electrodes and carbon paste electrodes. Sigmoidal-shape voltammograms wereobserved and steady-state currents were quickly achieved on these electredes.

关键词： Method the Fabrication New Carbon

Laboratory Assessment of Lubricants for Wheel/Rail Lubrication

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 57-60页

作者： Zhao, XZ Liu, jj Zhu, BL Wang, CY ZHENGZHOU RES INST MECH ENGN ZHENGZHOU 450052PEOPLES R CHINA

The antiwear properties of two wheel/rail lubricating oils were tested and compared on an Amsler machine. Under same testing conditions, oil A (developed by authors) showed much better wear resistance and higher load-carrying capacity than oil B (imported from abroad). The X-ray diffraction (XRD) analyses of the worn surfaces showed that different extreme pressure (EP) lubricating films were formed on the surfaces when the rollers were lubricated with different oils under boundary lubrication condition. The EP film of oil A was a composite film containing three compounds, FeO, FeSx and FeP, while oil B formed only a simple EP film of FePO4. The composite EP film showed lower shear strength and better antiwear property than the simple EP film, which brought about different wear resistance df the two wheel/rail lubricating oils.

关键词： Lubricating oils

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

Sliding Wear of Ceramic/Metal Pairs under Boundary Lubrication of Water and Oil

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 409-415页

作者： Zhao, XZ Liu, jj Zhu, BL Luo, ZB Miao, HZ Tribology Research Institute Tsinghua University Beijing 100084 China

In order to reveal the wear mechanism of ceramic cutting tools in real cutting process, a simulation test was carried out on a block-on-ring tribometer. The investigation was conducted at ambient temperature to determine the wear behaviour of ceramic/metal tribe-systems under boundary lubrication of water and oil. In this test, the boundary lubrication conditions were provided by dropping oil or water into contact area at a rate of 5 drops per minute (about 0.1 ml/min). The tested materials are Al2O3-Ti(CN) composite ceramic, Al(purity>99.5 wt pet), Fe(C<0.04 wt pet) and a stainless steel (ASTM 302), which combined into three ceramic/metal frictional pairs. The test results indicate that wear loss of the materials increases with load and speed. Compared with unlubricated conditions, the boundary lubrication condition made the materials wear more serious, which show that lubricating method is very important to a tribe system, and unsuitable lubricating method could increase the wear of materials instead of reducing it. The surfaces of the ceramic and the metallic samples were analysed by using a scanning electron microscope with energy-dispersive X-ray attachment, which indicate that material transfer occurred between the ceramic and metallic materials. The wear mechanism was discussed.

关键词： Ceramic cutting tools