Electric Anisotropy and Two－dimensional Energy Band of Undoped and Heavily Doped Polyacetylene

ＥｌｅｃｔｒｉｃＡｎｉｓｏｔｒｏｐｙａｎｄＴｗｏ－ｄｉｍｅｎｓｉｏｎａｌＥｎｅｒｇｙＢａｎｄｏｆＵｎｄｏｐｅｄａｎｄＨｅａｖｉｌｙＤｏｐｅｄＰｏｌｙａｃｅｔｙｌｅｎｅＨＵＡＮＧＺｏｎｇ－ｌｉａｏ，ＷＡＮＧＸｉｕ－ｊｕｎ，ＴＯＮＧＬａ－ｇａ，ＬＩＢａｉ...     

Synthesis and Biological Evaluation of Substituted 3＇－N－Benzoyl Taxol Analogs

ＳｙｎｔｈｅｓｉｓａｎｄＢｉｏｌｏｇｉｃａｌＥｖａｌｕａｔｉｏｎｏｆＳｕｂｓｔｉｔｕｔｅｄ３＇－Ｎ－ＢｅｎｚｏｙｌＴａｘｏｌＡｎａｌｏｇｓＱｉｎＹＵＥ；Ｑｉ－ＣｈｅｎｇＦＡＮＧａｎｄＸｉａｏＴｉａｎＵＡＮＧ（ＩｎｓｉｔｉｔｕｔｅｏｆＭａｔｅｒｉａＭｅ...     

Initiation Mechanism of Polymerization of Acryl－amide by Ceric Ion／2－Benzoyl Acetanilide System

ＩｎｉｔｉａｔｉｏｎＭｅｃｈａｎｉｓｍｏｆＰｏｌｙｍｅｒｉｚａｔｉｏｎｏｆＡｃｒｙｌ－ａｍｉｄｅｂｙＣｅｒｉｃＩｏｎ／２－ＢｅｎｚｏｙｌＡｃｅｔａｎｉｌｉｄｅＳｙｓｔｅｍＤＯＮＧＪｉａｎ－ｈｕａ，ＤＥＮＧＣｈａｏ，ＱＩＵＫｕｎ－ｙｕａｎａｎｄＦＥＮＧ...     

Semisynthesis and Biological Evaluation of Taxayuntin 13－［N－Benzoyl－（2’R，3’S）－3’－phenylisoserinate］

ＳｅｍｉｓｙｎｔｈｅｓｉｓａｎｄＢｉｏｌｏｇｉｃａｌＥｖａｌｕａｔｉｏｎｏｆＴａｘａｙｕｎｔｉｎ１３－［Ｎ－Ｂｅｎｚｏｙｌ－（２’Ｒ，３’Ｓ）－３’－ｐｈｅｎｙｌｉｓｏｓｅｒｉｎａｔｅ］ＱｉｎＹＵＥ；ＱｉＣｈｅｎｇＦＡＮＧａｎｄＸｉａｏＴｉａｎＬＩＡ...     

STUDIES ON MACROCYCLIC DITERPENOIDS（XI）──A Convergent and Stereoselective Synthesis of Cembrenene Precursor－4，10－Dimethyl－7－Isopropenyl－14－Oxo－3Z，5E，10E－Pentadecatrienal

ＳＴＵＤＩＥＳ　ＯＮ　ＭＡＣＲＯＣＹＣＬＩＣ　ＤＩＴＥＲＰＥＮＯＩＤＳ（ＸＩ）──Ａ　Ｃｏｎｖｅｒｇｅｎｔ　ａｎｄ　Ｓｔｅｒｅｏｓｅｌｅｃｔｉｖｅ　Ｓｙｎｔｈｅｓｉｓ　ｏｆ　Ｃｅｍｂｒｅｎｅｎｅ　Ｐｒｅｃｕｒｓｏｒ－４，１０－Ｄｉｍｅｔｈｙｌ－７－Ｉ...     

STUDIES ON THE SYNTHESIS OF SESAMIN－GROUP LIGNANS V． A CONVENIENT METHOD FOR THE PREPARATION OF 2－ARYL－4－PHENYLOXAZOLES

ＳＴＵＤＩＥＳＯＮＴＨＥＳＹＮＴＨＥＳＩＳＯＦＳＥＳＡＭＩＮ－ＧＲＯＵＰＬＩＧＮＡＮＳＶ．ＡＣＯＮＶＥＮＩＥＮＴＭＥＴＨＯＤＦＯＲＴＨＥＰＲＥＰＡＲＡＴＩＯＮＯＦ２－ＡＲＹＬ－４－ＰＨＥＮＹＬＯＸＡＺＯＬＥＳ￥Ｃｏｒｒｅｓｐｏｎｄｅｎｔａｕｔｈｏｒ．２－ａｒｙｌ－４－ｐｈｅｎｙｌｏｘａｚｏｌｅｓ．Ｔｈｅｏｔｈｅｒｏｌｌｅｂｙｔｈｅｒｅａｃｔｉｏｎｏｆａ－ｍｅｔｈｙｌｐｈｅｎａｃｙｌｂｅｎｚｏａｔｅｗｉｔｈａｍｍｏｎｉｕｍａｃｅｔａｔｅｉｎｂｏｉｌｉｎｇａｃｅｔｉｃａｃｉｄｔｏｆｏｒｍａｆｕｔｕｒｅｏｆ２，４－ｄｉｐｈｅｎｙｌ－５ｍｅｔｈｙｌｏｘａｚｏｌｅａｎｄ２，４－ｄｉｐｈｅｎｙｌ－５－ｒｎｅｔｈｙｌｉｎｄｄａｚｏｌｅｂｏｔｈｉｎａｂｏｕｔ４０％ｙｉｅｌｄ，ｈｉｌｔｔｉｌｌｓｍｅｔｈｏｄｉｓａｐｐｌｉｃａｂｌｅｆｏｒｔｈｅｐｒｅｐａｒａｔｉｏｎｏｆ２－ａｒｙｌ－４－ｐｈｅｎｙｌｏｘａｚｏｌｅｓ．Ｂｙａｎａｌｏｇｙ，ｐｌｉｅｎａｃｙｌｂｅｎｚｏａｔｅｉｓａｌｌｏａｌｌｏｗｅｄｔｏｒｅａｃｔｗｉｔｈａｌｎｍｏｎｉｌｌｍａｃｅｔａｔｅｉｎｂｏｉｌｉｎｇａｃｅｔｉｃａｃｉｄ．Ａｍｉｘｔｕｒｅｏｆ２，４－ｄｉｐｈ     

Synthesis and Diffuse Reflectance Spectrum of Open－framework Cobalt Phosphate DAF－2 From Alcoholic System

ＳｙｎｔｈｅｓｉｓａｎｄＤｉｆｆｕｓｅＲｅｆｌｅｃｔａｎｃｅＳｐｅｃｔｒｕｍｏｆＯｐｅｎ－ｆｒａｍｅｗｏｒｋＣｏｂａｌｔＰｈｏｓｐｈａｔｅＤＡＦ－２ＦｒｏｍＡｌｃｏｈｏｌｉｃＳｙｓｔｅｍＹＵＪｉ－ｈｏｎｇ;ＣＨＥＮＪｉｅ－ｓｈｅｎｇａｎｄＸＵＲｕ－ｒ...     

An Oscillation Condition for an Electrode－separated Piezoelectric Sensor in Non－electrolyte Liquid

ＡｎＯｓｃｉｌｌａｔｉｏｎＣｏｎｄｉｔｉｏｎｆｏｒａｎＥｌｅｃｔｒｏｄｅ－ｓｅｐａｒａｔｅｄＰｉｅｚｏｅｌｅｃｔｒｉｃＳｅｎｓｏｒｉｎＮｏｎ－ｅｌｅｃｔｒｏｌｙｔｅＬｉｑｕｉｄＳＨＥＮＤａ－ｚｈｏｎｇ，ＨＵＡＮＧＭｉｎｇ－ｓｈａｎ，ＬＩＮＳｏｎｇ，Ｎ...     

Determination of Elements of Groups Ⅲ A and Ⅳ A Using Microwave Plasma Torch Atomic Emission Spectrometry

ＤｅｔｅｒｍｉｎａｔｉｏｎｏｆＥｌｅｍｅｎｔｓｏｆＧｒｏｕｐｓⅢＡａｎｄⅣＡＵｓｉｎｇＭｉｃｒｏｗａｖｅＰｌａｓｍａＴｏｒｃｈＡｔｏｍｉｃＥｍｉｓｉｏｎＳｐｅｃｔｒｏｍｅｔｒｙＺＨＡＮＧＨａｎ－ｑｉ，ＹＵＡＮＸｉａｎｇ－ｌｉｎ，ＬＩＡＮＧＦｅｎｇ，Ｌ...     

STUDIES ON MACROCYCLIC DITERPENOIDS（Ⅻ）──A Convergent and Stereoselective Synthesis of Sarcophytol－Q Precursor──（11S）－3，7，11，15－Tetramethyl－11－Hydroxy－14－Oxo－3E，7E，12E－Hexadecatrienal

ＳＴＵＤＩＥＳＯＮＭＡＣＲＯＣＹＣＬＩＣＤＩＴＥＲＰＥＮＯＩＤＳ（Ⅻ）──ＡＣｏｎｖｅｒｇｅｎｔａｎｄＳｔｅｒｅｏｓｅｌｅｃｔｉｖｅＳｙｎｔｈｅｓｉｓｏｆＳａｒｃｏｐｈｙｔｏｌ－ＱＰｒｅｃｕｒｓｏｒ──（１１Ｓ）－３，７，１１，１５－Ｔｅｔｒａｍｅｔ...     

The enthalpies of formation and reorganization of aromatic radicals

The enthalpies of formation of some biphenyl derivatives were determined. A "double difference" method for calculating the enthalpies of formation of aromatic radicals and the bond dissociation energies was proposed. The enthalpies of formation of the radicals biphenyl, diphenyl oxide, and phenyl oxide were determined. The energies of reorganization of these radicals as well as phenyl and 4-, 3-, and 2-pyridyls were calculated. The sums of the energies of the chemical bonds in the molecular moieties transformed into radicals upon the decomposition of chemical compounds were found to be constant for different compounds. The energies of the chemical bonds in arenes were determined.     

A Kinetic Study of Selective Hydrogenation of Carbon Monoxide to C2 Oxygenates on Rh-Mn-Li-Fe／SiO2 Catalyst

The kinetics of CO hydrogenation for the synthesis of C2 oxygenates over Rh-Mn-Li-Fe/SiO2 was investigated. Kinetic parameters for the formation of ethanol, acetaldehyde. C2 oxygenates, methanol and methane were obtained. The activation energy, H2 and CO dependence orders for ethanol and acetaldehyde formation differed greatly, the large difference seemed to imply that they were formed through different intermediates.     

聚吡咯纳米线的恒电位合成及形貌分析

采用恒电位法,直接在石墨电极表面快速合成聚吡咯纳米线,并重点研究了聚吡咯纳米线的生成过程及形貌变化规律。结果表明,聚吡咯纳米线的生成包括成核和生长过程,纳米线的形貌随聚合条件的不同而变化,直径随聚合电位、吡咯单体浓度、电解质浓度的升高而增大,这是由于不同聚合条件下聚吡咯的成核速率不同引起的。     

交流放电法合成多种形态的碳纳米管

碳纳米管的发现［１］引起了科学界的广泛重视,人们对于这种新型材料在纳米导线、高强纤维、超导等方面的应用寄予厚望．目前,合成碳纳米管的方法主要是采用不等径石墨棒直流放电,在阴极上得到含有碳纳米管的沉积物［２］．对于碳纳米管的应用,有关的理论研究［３］及...     

Oxidation of lipids and membranes I: in vitro formation of peroxidative lipid polymers.

Fluorescent polymers were obtained by oxidizing partly emulsified linolenic acid with different oxidants. The speed of formation of polymers differed for the various oxidants, and the difference was not a simple function of the oxidation potential. The speed of polymerization also depended on the nature of the emulsion. The presence of egg albumen in the emulsion enhanced polymer formation with all oxidants. When the oxidants used are arranged in the order of decreasing speed of polymer formation, the order is different in the presence of albumen from what it is in the absence of albumen. With different oxidation catalysts most antioxidants and amino acids tested enhanced polymerization. In oxidation with ferric ions, with K-dichromate, and without added oxidants the only antioxidants which delayed polymerization were "inhibitors." "Retarders" enhanced polymerization. With KMnO4 slight delay was caused by some retarders. The findings indicate that not only oxidation catalysts, but also proteins, amino acids, and antioxidants enhance polymerization. The possibility is suggested that in animal cells lipid pigment formation might represent a mechanism for neutralizing free radicals.     

Utilization of thermodesorption coupled to GC-MS to study stability of different wood species to thermodegradation

Thermodesorption coupled to gas chromatography coupled to mass spectroscopy (TD-GC-MS) has been investigated to identify volatile degradation products generated during wood heat treatment by mild pyrolysis. For this purpose, wood samples of different softwood and hardwood species have been heat treated under nitrogen for different temperatures comprised between 180 and 230 °C during 15 min in the glass thermal desorption tube of the thermodesorber and the volatile wood degradation products trapped. The trapped products were then thermodesorbed and analysed by GC-MS. Chromatograms of the different samples indicated the formation of different products resulting from degradation of lignin and hemicelluloses. Hardwoods were shown to be more sensitive to thermodegradation than softwoods, for which degradation products appear at slightly higher temperature. The important formation of acetic acid is concomitant with the formation of most of degradation products and at the origin of the difference of reactivity observed between softwoods and hardwoods.     

On the formation of macrovoids in PMMA membranes

In this work, the formation of macrovoids in two membrane formation systems was investigated. The polymer and the coagulant used in these two systems were the same: PMMA and water, but the solvents used to dissolve PMMA were different – NMP for one system (system A) and acetone/Tween 80 solution for the other (system B). According to SEM and AFM analyses, it was found that, although the macrostructures of the membranes fabricated by systems A and B are similar, the microstructures are different. On the basis of optical observation of the growth of macrovoids, it is proposed that the difference in the microstructure can be explained by the difference in the growth mechanism of macrovoids: the growth of macrovoids is by convection for system A and by diffusion for system B. The difference in the growth mechanism of macrovoids can also account for some other differences between systems A and B: system B is more sensitive to the casting thickness than system A, and the addition of salt in the coagulation bath can effectively inhibit the growth of macrovoids in system B but not in system A.     

伯胺N1923萃取体系反胶束的形成研究

伯胺 N1 92 3是重要的国产萃取剂 ,其经酸化后生成的铵盐在有机相中可聚集形成反向胶束或微乳液[1] ,但在盐酸和硫氰酸等一元酸介质中萃取金属时 ,萃取剂的聚集现象对萃取机理影响不大 ,可用斜率法分析实验结果 ,确定萃合物组成 [2 ] .而在硫酸介质中却表现出特殊的萃取现象 ,发生胶束萃取[3] .对此 ,本文试图从表面与胶体化学的角度对伯胺萃取体系反胶束的形成作深入研究 ,以期对伯胺萃取体系的萃取机理获得更深入的了解 .1　实验部分1 .1　试剂与仪器　伯胺 N1 92 3( RNH2 ) ,平均分子量 2 91 .8(中国科学院上海有机化学研究所实验厂 ) …     

Stereocomplex Crystallization in Asymmetric Diblock Copolymers Studied by Dynamic Monte Carlo Simulations

Stereocomplex crystallization in asymmetric diblock copolymers was studied using dynamic Monte Carlo simulations, and the key factor dominating the formation of stereocomplex crystallites(SCs) was uncovered. The asymmetric diblock copolymers with higher degree of asymmetry exhibit larger difference between volume fractions of beads of different blocks, and local miscibility between different kinds of beads is lower, leading to lower SC content. To minimize the interference from volume fraction of beads, the SC formation in blends of asymmetric diblock copolymers was also studied. For the cases where the volume fractions of beads of different blocks are the same, similar local miscibility between beads of different blocks and similar SC content was observed. These findings indicate that the volume fraction of beads of different blocks is a key factor controlling the SC formation in the asymmetric diblock copolymers. The SC content can be regulated by adjusting the difference between the contents of beads of different blocks in asymmetric diblock copolymers.     

Calculated bulk vacancy formation energy (Ev) for a Schottky defect in Al single crystals

In this paper the bulk vacancy formation energies (E_v) of Al single crystals (with different surface orientations (111), (100) and (110)) were calculated with the embedded atom method using the empirical many‐body potential of Sutton and Chen. These calculations indicate that there is a significant difference in the bulk vacancy formation energy underneath different surface orientations. The crystal with the (111) surface had the highest bulk vacancy formation energy and the crystal with the (110) surface had the lowest bulk vacancy formation energy. Copyright © 2003 John Wiley & Sons, Ltd.