检索结果-南通市图书馆

Effect of Bi_2O_3 Additive on the Microstructure and Dielectric Properties of BaTiO_3-Based Ceramics Sintered at Lower Temperature

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

Journal of Materials Science & Technology 2010年第5期26卷 472-476页

作者： Shunhua wu Xuesong wei Xiaoyong wang Hongxing Yang Shunqi Gao Institute of Electronic and Information Engineering Tianjin University Tianjin 300072 China

High performance X8R dielectric ceramics were prepared by dopingBi2O3 to BaTiO3-based *** effect of small amounts（≤1.2 mol%） ofBi2O3 additive on the microstructure and dielectric properties of BaTiO3-based ceramics have been *** Bi2O3 ,acting as a sintering additive,can effectively lower the sintering temperature of BaTiO3-based ceramics from 1300 to 1130 °*** bulk density of BaTiO3-based ceramics increased and reached the maximum value with increasingBi2O3 *** dielectric constant increased with increasingBi2O3 until it reached the maximum value with 0.8 mol%Bi2O3 additive,and the dielectric loss decreased with increasingBi2O3 *** dielectric properties of ε=2470,tanδ=0.011 and △ε/ε 25 ≤±9%（-55-150 °C） were obtained for the BaTiO3-based ceramics doped with 0.8 mol%Bi2O3 sintered at 1130 °C for 6 h.

关键词： BaTiO3-based ceramics Bi2O3 Dielectric properties X8R

Photoelectric properties of thin Eu^(3+)-doped TiO_2 films sensitized by cis-RuL_2(SCN)_2·2H_2O

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第z1期25卷 169-172页

作者： wu Xiaohong QIN wei wang Song JIANG Zhaohua GUO Yun XIE Zhaoyang Department of Applied Chemistry Harbin Institute of Technology Harbin 150001 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Department of Applied Chemistry Harbin Institute of Technology Harbin 150001 China Department of Applied Chemistry Harbin Institute of Technology Harbin 150001 China National Laboratory of Vacuum & Cryogenics Technology and Physics Lanzhou 730000 China National Laboratory of Vacuum & Cryogenics Technology and Physics Lanzhou 730000 China

Thin nanocrystalline TiO2 films doped by europium ions (Eu3+) were obtained by the sol-gel method. The photoelectric properties of Eu3+-doped TiO2 film electrode sensitized by cis-RuL2(SCN)2·2H2O (L=cis-2,2′-bipyridine-4,4′-dicarboxlic acid) ruthenium complex were studied. The thin films were characterized by X-ray diffraction, atomic force microscopy and X-ray photoelectron spectroscopy. Effect of doping Eu3+ on microscopic structure and photoelectrical properties were discussed. The result shows that doping europium ions makes specific surface area of these films larger, which contributes to improving the photoelectric properties. It is found that an optimal composition doped with 0.2 mol.% Eu3+ exhibits the highest photoelectric properties. Isc is 0.37 mA·cm-2, which is 0.17 mA·cm-2 bigger than that of un-doped films; Voc is 405 mV, which is 50 mV bigger than that of un-doped films.

关键词： europium ions nanocrystalline TiO2 films photoelectric properties

Recent developments in homobimetallic reagents and catalysts for organic synthesis

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2011年第17期56卷 1753-1769页

作者： wu wei GU DeLiang wang ShiMeng NING YingNan MAO GuoLiang Provincial Key Laboratory of Oil and Gas Chemical Technology College of Chemistry and Chemical Engineering Northeast Petroleum University Daqing 163318 China

Organometallics are a family of useful organic chemicals because they play important roles in organic synthesis as reagents and as *** can be classified according to the number of metals they *** compounds are important organometallics and they are either homobimetallic or heterobimetallic depending on whether the two metals are the same or *** this paper,we focus on homobimetallic *** compounds are generally used as dianions to react with electrophiles in organic ***,homobimetallics have also been used as catalysts in organic reactions such as in asymmetric reactions.

关键词：有机合成试剂催化剂有机金属化合物有机化工原料双金属化合物有机反应不对称反应数量分类

Synthesis of Racemic Bis[2-(6-fluoro-2-chromanyl)-2-hydroxyethyl]-amine Methanesulfonic Acid Salt Using Lithium Aluminum Amide as a Promoter in Regioselective Ring Opening of Epoxide

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2005年第12期16卷 1577-1580页

作者： Yun Xu YANG Nai Xing wang Ya Lan XING wu wei wang Jia ZHAO Gui Xia wang Shi TANG Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100101 Beijing University of Chemical Technology Beijing 100029

Lithium aluminium amide [LiAI（NHR）4] 5 obtained by treating the primary amine 4 with LiAlH4 could promote the ring opening of epoxide 2 and led to high regioselective product of racemic bis[2-（6-fluoro-2-chromanyl... 详细信息

关键词： Epoxide lithium aluminium amide bis[2-(6-fluoro-2-chromanyl)-2-hydroxyethyl]-amine

Left atrial minimum volume by real-time three-dimensional echocardiography as an indicator of diastolic dysfunction

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2013年第22期126卷 4227-4231页

作者： LIN Qiong-wen wang wu-gang wu wei-chun wang Hao Department of Echocardiography Fuwai Hospital Chinese Academy of Medical Sciences Peking Union Medical College Beijing 100037 China

Background Left atrial （LA） maximum volume is becoming a prognostic biomarker for left ventricular （LV） diastolic dysfunction. However, we assessed LV diastolic function by measuring LA phasic volumes using real-time threedimensional echocardiography （RT3DE） in patients with stable coronary artery disease （CAD）. Methods Sixty-five stable CAD patients with normal LV ejection fraction （LVEF） were divided into three groups according to degree of coronary stenosis： control （n=15） with 〈50% stenosis as control group, mildS （n=25） with mild stenosis （50%- 70%） and severeS （n=25） with 〉70% stenosis. LA phasic volumes and function were evaluated and compared using RT3DE and two dimensional echocardiography （2DE）. N-terminal pro-B-type natriuretic peptide （NT-proBNP） levels were examined. The correlations of RT3DE-derived parameters with other conventional indices were analyzed. Results Significant correlations between RT3DE and 2DE for LA volume measurements were： control, r=0.93; mildS, 1=0.94; severeS, r=0.90 （all P 〈0.05）. Patients with severe coronary stenosis presented higher NT-proBNP level, indices of LA minimum volume and volume before atrial contraction, but lower LA total emptying fraction （LAEF） and LAEFpass^ve. Significant correlations of RT3DE derived LA volume indices with E/E＇（r=0.695） and NF-proBNP （r=0.630） level were found. Conclusions RT3DE derived, LA indices correlate well with NT-proBNP level and may be superior to 2DE measurements for the evaluation of LV diastolic dysfunction. Enlargement of LA minimum volume in stable CAD patients without systolic dysfunction appears earlier and may be better correlated with LV diastolic function than that of LA maximum volume.

关键词： real-time three-dimensional echocardiography left atrial volume diastolic dysfunction, coronary arterydisease, N terminal pro B type natriuretic peptide

A General Review of the Situation in Latin America and the Caribbean in 2008

在线全文

学校读者我要写书评

暂无评论

International Understanding 2008年第4期 13-18页

作者： wu Guoping wang wei

In 2008, Latin America and the Caribbean are amaintained the momentum of economic ***, the pace of growth slowed down due to various factors. The stagnant impact of

关键词： 2008年拉丁美洲加勒比海地区经济形势金融危机

Point-Tree Structure Genetic Programming Method for Discontinuous Function's Regression

在线全文

学校读者我要写书评

暂无评论

wuhan University Journal of Natural Sciences 2003年第S1期8卷 323-326页

作者： Xiong Sheng-wu, wang wei-wuSchool of Computer Science and Technology, wuhan University of Technology, wuhan 430070, Hubei. China wuhan University of Technology School of Computer Science and Technology Wuhan Hubei China (GRID:grid.162110.5) (ISNI:***)

A new point-tree data structure genetic programming (PTGP) method is proposed. For the discontinuous function regression problem, the proposed method is able to identify both the function structure and discontinuities points simultaneously. It is also easy to be used to solve the continuous function's regression problems. The numerical experiment results demonstrate that the point-tree GP is an efficient alternative way to the complex function identification problems.

关键词： genetic programming symbolic regression point-tree structure

G8 at the Turning Point

在线全文

学校读者我要写书评

暂无评论

International Understanding 2008年第3期 7-10页

作者： wu Xingtang wang wei

After three days of meeting, G8 Summit was officially concluded on July9th in Toyako, Hokkaido of Japan. The three-day summit touched upon major international issues such as world economy,

关键词：八国集团国际关系外交策略全球化

The Ghosts of War Criminals in the Yasukuni Shrine

在线全文

学校读者我要写书评

暂无评论

International Understanding 2005年第2期 14-18页

作者： wu Guangyi,wang wei

On the occasion of the 60^th anniversary of the victory of the world anti-fascism war as well as the Chinese anti-Japanese war, when people everywhere are drawing lessons from the nightmare of the war and keeping the history in mind for the sake of maintaining the world peace, Japan is still haunted by its idea of militarism and the Japanese leaders are also claiming to continue their visits to the Yasukuni Shrine where a large number of war criminals are honored. This has triggered off the strong indignation of many people.

关键词：反法西斯战争战争罪犯靖国神社日本政治态度