检索结果-南通市图书馆

Science China chemistry 2009年第8期52卷 1097-1103页

作者： LI XiangJun,ZHENG Na,HU ZhongBo & YUAN ZhuoBin college of chemistry and chemical {3.,graduate university of chinese academy of sciences,beijing 100049,China 1. college of chemistry and chemical {3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

A series of Nd1-yDyyFe11-xTiMx(M=Mo,Si) alloys have been prepared by arc melting and studied by X-ray diffraction and neutron *** samples are found to crystallize in the ThMn12-type *** lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11-xTiMox alloys increase linearly with increasing content of Mo(x),while the lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11-xTiSix alloys decrease linearly with increasing content of Si(x).In NdyDy1-yFe11-xTiMx(M=Mo,Si) compounds,Ti and Mo atoms preferentially occupy the 8i sites and Si atoms preferentially occupy the 8j and 8f *** measurements show that the substitution of Fe by either Mo or Si leads to a decrease in the Curie temperature.

关键词： rare earth-transition metal compounds crystal structure X-ray diffraction neutron diffraction

An efficient chiral synthesis of (R)-N-[3.acetyl-4-(2-hydroxy-3.isopropylamino-propoxy)phenyl]-butanamide with high enantioselectivity

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2009年第8期52卷 1216-1219页

作者： WANG NaiXing1,2 & TANG XinLiang1,3.1 Technical Institute of Physics and chemistry,chinese academy of {3.,beijing 100080,China 2 college of chemistry and chemical engineering,graduate university of chinese academy of sciences,beijing 100049,China 3.School of chemical engineering and Environment,beijing Institute of Technology,beijing 100081,China 1. Technical Institute of Physics and chemistry Chinese Academy of Sciences Beijing 100080 China 2. college of chemistry and chemical {3. Graduate University of Chinese Academy of Sciences Beijing 100049 China 3. School of chemical engineering and Environment Beijing Institute of Technology Beijing 100081 China

R-Enantiomer of the β-receptor antagonist N-[3.acetyl-4-(2-hydroxy-3.isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** product was detected by 1H NMR,13. NMR,and MS,and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HPLC analysis

Meet Our New Editorial Board Members of Spotlights

在线全文

学校读者我要写书评

暂无评论

chinese Journal of chemistry 2024年第16期42卷 1932-1936页

作者： Editorial Office of chinese Journal of chemistry 不详

Editorial Board Member of *** ***,college of Materials Science and engineering beijing {3. of chemical ***:2006-2010,B.S.,Materials Science and engineering,beijing {3. of chemical Technology.2010-2015,Ph... 详细信息

关键词： Spotlight Editorial Board

Changes of decay rates of radioactive ^(111)In and ^(3.)P induced by mechanic motion

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

Science China chemistry 2007年第2期50卷 170-174页

作者： HE YuJian1,QI Fei2 & QI ShengChu3.1 college of chemistry and chemical {3.,graduate university of chinese academy of sciences,beijing 100049,China 2 No. 1,Gravenhurst Court,Gaithersburg,Md 20878,USA 3.Department of Applied chemistry,Peking university,beijing 100871,China 1. college of chemistry and chemical {3. Graduate University of Chinese Academy of Sciences Beijing 100049 China 2. No. 1 Gravenhurst Court Gaithersburg Md 20878 USA 3. Department of Applied chemistry Peking University Beijing 100871 China

The changes of decay rates of radionuclide 111In(electron capture) and 3.P(β decay) induced by exter-nal mechanic motion are studied. The results indicate that,in the external circular rotation in clockwise and anticlockwise centrifuge on Northern Hemisphere(radius 8 cm,2000 r/min) ,the half life of 111In compared with the referred(2.83.d) is decreased at 2.83. and increased at 1.77%,respectively;the half life of 3.P compared with the referred(14.29 d) is decreased at 3.78% and increased at 1.75%,respec-tively. When the clockwise and anticlockwise rotations increase to 4000 r/min,the half life of 111In is decreased at 11.3.% and increased at 6.3.%,respectively;the half life of 3.P is decreased at 10.08% and increased at 4.3.%,respectively. When the circular rotation is removed,the decay rates of 111In and 3.P return back to the referred,respectively. It is found that the external circular rotations in clockwise and anticlockwise centrifuge selectively increased and decreased the decay rates of 111In and 3.P,respec-tively,and the effects are strongly dependent on the strength of circular rotation. It is suggested that these effects may be caused by the chiral interaction.

关键词： circular rotation helical motion 111In 3.P decay rate chirality

SiO/CNTs:A new anode composition for lithium-ion battery

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2009年第12期52卷 2047-2050页

作者： REN YuRong1,2,3.,QU MeiZhen1 & YU ZuoLong1 1 Chengdu Institute of Organic chemistry,chinese academy of {3.,Chengdu 610041,China 2 college of chemistry,Jilin Normal university,Siping 13.000,China 3.graduate university of chinese academy of sciences,beijing 10003.,China 1. Chengdu Institute of Organic chemistry Chinese Academy of Sciences Chengdu 610041 China 2. college of chemistry Jilin Normal University Siping 136000 China 3. graduate university of chinese academy of sciences Beijing 100039 China

A new anode composition SiO/CNTs (carbon nanotubes) has been prepared by chemical vapor deposition (CVD) method. The results of scanning electron microscopy (SEM) confirm that CNTs deposit on small SiO particles,form a cage,and enwrap SiO particles tightly. SiO/CNTs anode composition exhibits an initial discharge and charge capacity of 1171 and 789 mAh/g,and maintains a reversible capacity of 500 mAh/g after 80 cycles. The improvement of the cyclic performance for SiO/CNTs composition is related to the maintaining of the electric network during cycling,which benefits from a tight contact between CNTs and SiO particles.

关键词： SiO/CNTs CVD composition anode Li-ion battery

Thermal expansion properties and hygro-scopicity of Y_(2-x)Sm_xW_3._(12) (x=0.0-0.4) compounds

在线全文

学校读者我要写书评

暂无评论

Science China(Technological sciences) 2008年第1期51卷 25-32页

作者： YU ZhouXiang1, PENG Jie2, WANG Hui2, WU MeiMei2, CHENG YingZhi2, HU ZhongBo2 & CHEN DongFeng1 1 China Institute of Atomic Energy, P.O. Box 275 (3.), beijing 102413. China 2 college of chemistry and chemical engineering, graduate university of chinese academy of sciences, {3., China China Institute of Atomic Energy P.O.Box 275 (30)Beijing 102413China college of chemistry and chemical {3. Graduate University of Chinese Academy of SciencesBeijing 100049China

A novel class of solid solutions of Y2-xSmxW3.12 (x = 0.0–0.4) were synthesized and studied by means of powder X-ray diffraction. All samples crystallize in an ortho- rhombic space group Pnca. The lattice parameters a, b and c of Y2-xSmxW3.12 in- crease with increasing Sm content. Since the compounds of this series hydrate at room temperature, thermogravimetric (TG) analysis was carried out. The result shows that the compound stores less water with increasing Sm content. The thermal expansion properties of Y2-xSmxW3.12 (x = 0.1, 0.3.and 0.4) were investi- gated with high temperature X-ray diffraction. Negative thermal expansion coeffi- cient αl becomes less negative from -6.644×10-6 to -6.211×10-6℃-1 when x changes from 0.1 to 0.4.

关键词： rare earth tungstates negative thermal expansion hygroscopic XRD

Formation of super-concentrated hydrochloric acid in the third phase in tertiary amine N23.-PtCl_6^(2-)-HCl system and its influences on the Pt microemulsion extraction

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2009年第11期52卷 1825-1834页

作者： HUANG Kun1,CHEN Jing1,ZHANG ChengFeng1,2,LI ZhiHong3.PAN QingHua1,SUN Yan1,LIU ShaoXuan1,LIU XueXin2,LI WeiHong1,YANG ZhanLan1,WENG ShiFu1,HU TianDou3.XU YiZhuang1 & WU JinGuang1 1 college of chemistry and Molecular engineering,Peking {3.,beijing 100871,China 2 Institute of chemistry,chinese academy of sciences,beijing 100190,China 3.Institute of High Energy Physics,chinese academy of sciences,{13.,China 1. college of chemistry and Molecular engineering Peking University Beijing 100871 China 2. Institute of chemistry Chinese Academy of Sciences Beijing 100190 China 3. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

In this paper,we have investigated the formation of the third-phase in tertiary amine(N23.)-PtCl62--HCl system and the microscopic phase structural evolution of platinum-loaded organic phases before and after the occurrence of the *** third-phase is characterized by various spectroscopic techniques,and the small angle X-ray scattering(SAXS) experiments demonstrate the appearance of nano-aggregates,i.e.,water-in-oil reversed micelles,in the third *** experimental results indicate that(1) formation of the third phase is related to the aggregation behaviors of nano-reversed micelles in which a super-concentrated hydrochloric acid formed with the H+ to H2O molar ratio being much higher than that of the conventional 3. wt% saturated hydrochloric acid.(2) The occurrence of the super-concentrated HCl results in a great amount of H+ and Cl-ions enriched and confined within the nano-water pools of W/O reversed micelles in third ***,the coordination behaviors of platinum complex ions in that super-concentrated hydrochloric acid are very different from their corresponding behaviors in bulk aqueous *** is possible that H+ ions participate in the formation of such complexes as HmPtCl6z+ in the super-concentrated hydrochloric acid.(3. The relative contents of various HmPtCl6z+ complexes are different corresponding to the H+ ion concentrations in confined nanowater *** association ability of the acidified tertiary amine N23. molecules(R3.H+) with various HmPtCl6z+ complexes plays an important role in affecting the platinum extraction behaviors.

关键词： solvent extraction third phase super-concentrated hydrochloric acid tertiary amine platinum

Heat capacity and thermodynamical properties of the crystal of [RE_2(Glu)_2(H_2O)_8](ClO_4)_4·H_2O (RE = Nd, Eu, Dy)

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2009年第7期52卷 862-867页

作者： WU XinMin1, LI Wei1, TAN ZhiCheng2 & QU SongSheng3.1 Department of chemical engineering, beijing Institute of Petro-chemical Technology, beijing 102617, China 2 Thermochemistry Laboratory, Dalian Institute of chemical Physics, chinese academy of sciences, Dalian 116023. China 3.college of chemistry and Molecular Science, Wuhan university, Wuhan 43.072, China Department of chemical engineering Beijing Institute of Petro-chemical Technology Beijing 102617 China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China college of chemistry and Molecular Science Wuhan University Wuhan 430072 China

Thermodynamical data of rare earth complexes with amino acid are important for engineering chemistry and fundamental chemistry. However, they have rarely been reported. In this work, a series of crystalline complexes of rare earth perchlorate coordinated with glutamic acid have been synthesized in water medium, and their thermodynamical data, including the heat capacity in low temperature range and the standard enthalpy of formation, were determined. These complexes were identified to be [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE = Nd, Eu, Dy) by using thermogravimetric analysis (TG), differential thermal analysis (DTA), and {3. and elementary analyses. Their purity has been determined. No melting points were observed for all the three complexes. The heat capacity of the complexes was measured by an adiabatic calorimeter from 79 to 3.0 K. Abnormal heat capacity values were detected for two of the complexes and the decomposition range of one complex was found. The temperature, enthalpy change and entropy change of the decomposition processes of the three complexes were calculated. The polynomial equations of heat capacity in the experimental temperature range have been obtained by least squares fitting. The standard enthalpy of formation was determined by an isoperibol reaction calorimeter at 298.15 K.

关键词： complex of rare earth, [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE = Nd, Eu, Dy Glu = glutamic acid), low-temperature heat capacity, standard enthalpy of formation

Status of study on biological and toxicological effects of nanoscale materials

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2005年第5期48卷 385-394页

作者： WANG Bing1, FENG Weiyue1, ZHAO Yuliang1, XING Gengmei1, CHAI Zhifang1, WANG Haifang2 & JIA Guang3.1. Laboratory for Bio-Environmental Health sciences of Nanoscale Materials (Nanosafety Lab), Institute of High Energy Physics, Chi-nese academy of sciences, {3., China 2. college of chemistry and Molecular engineering, Peking university, beijing 100871, China 3. Department of Occupational and Environmental Health sciences, School of Public Health, Peking university, beijing 100083. China 1. Laboratory for Bio-Environmental Health sciences of Nanoscale Materials (Nanosafety Lab) Institute of High Energy Physics Chinese Academy of Sciences 100049 Beijing China 2. college of chemistry and Molecular engineering Peking University 100871 Beijing China 3. Department of Occupational and Environmental Health sciences School of Public Health Peking University 100083 Beijing China

Because the physical and chemical properties of nanosized materials mostly differ from the existing microsized materials, their potential impacts on human health and the envi-ronment will be topics under the serious discussions in press and in a number of international scientific journals. We analyze and summarize the existing data of the experimental study on the biological activities and adverse effects of nanoscale materials/particles including single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron powders. Though some biological behaviors of nanoscale materials observed cannot be understood on the basis of the current knowledge, as the existing data are mostly preliminary, it is too early to make some ex-clusive conclusions on biological activities (or the toxicity) of any of nanoscale materials. The experimental techniques, the current topics, and the future research directions for this new re-search field are also discussed.

关键词： nanomaterials, single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron, biological activity and toxicological effect.

Controlling the Molecular Weight and Molecular Weight Distribution using Compressed CO_2 Antisolvent

在线全文

学校读者我要写书评

暂无评论

chinese chemical Letters 2000年第10期11卷 933-934页

作者： Jun LIU, Zhi Min LIU, Bu Xing HAN, Jian WANG, Qing HUO, Fang Fang LIU (Center For Molecular sciences, Institute of chemistry, chinese {3. of sciences, beijing 100080 (chemical engineering college of beijing United university, beijing 100023. (Department of chemical engineering, university of Science and Technology of Hebei, Shijiazhuang 050018) chinese Acad Sci Inst Chem Ctr Mol Sci Beijing 100080 Peoples R China beijing United Univ Chem Engn Coll Beijing 100023 Peoples R China Univ Sci & Technol Hebei Dept Chem Engn Shijiazhuang 050018 Peoples R China

Effect of CO2 dissolved in tetrahydrofuran (THF) on the polymerization of styrene in THF was studied at 3.3.2 K and different pressures. It was found that the molecular weight (MW) and MW distribution of the polystyre... 详细信息

关键词： CO_2 antisolvent styrene polymerization