Synthesis,characterization, and micellization of an epoxy‐based amphiphilic diblock copolymer of ϵ‐caprolactone and glycidyl methacrylate by enzymatic ring‐opening polymerization and atom transfer radical polymerization

Amphiphilic diblock copolymer polycaprolactone‐block‐poly(glycidyl methacrylate) (PCL‐b‐PGMA) was synthesized via enzymatic ring‐opening polymerization (eROP) and atom transfer radical polymerization (ATRP). Methanol first initiated eROP of ?‐caprolactone (?‐CL) in the presence of biocatalyst Novozyme‐435 under anhydrous conditions. The resulting monohydroxyl‐terminated polycaprolactone (PCL–OH) was subsequently converted to a bromine‐ended macroinitiator (PCL–Br) for ATRP by esterification with α‐bromopropionyl bromide. PCL‐b‐PGMA diblock copolymers were synthesized in a subsequent ATRP of glycidyl methacrylate (GMA). A kinetic analysis of ATRP indicated a living/controlled radical process. The macromolecular structures were characterized for PCL–OH, PCL–Br, and the block copolymers by means of nuclear magnetic resonance, gel permeation chromatography, and infrared spectroscopy. Differential scanning calorimetry and wide‐angle X‐ray diffraction analyses indicated that the copolymer composition (?‐CL/GMA) had a great influence on the thermal properties. The well‐defined, amphiphilic diblock copolymer PCL‐b‐PGMA self‐assembled into nanoscale micelles in aqueous solutions, as investigated by dynamic light scattering and transmission electron microscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5037–5049, 2007     

A supramolecular hydrogen‐bonded complex between 1,3,5‐tris(diisobutylhydroxysilyl)benzene and trans‐bis(4‐pyridyl)ethylene

The trisilanol 1,3,5‐(HOi‐Bu₂Si)₃C₆H₃ ( 7 ), prepared in three steps from 1,3,5‐tribromobenzene via the intermediates 1,3,5‐(Hi‐Bu₂Si)₃C₆H₃ ( 8 ) and 1,3,5‐(Cli‐Bu₂Si)₃C₆H₃ ( 9 ) forms an equimolar complex with trans‐bis(4‐pyridyl)ethylene (bpe), 7 ·bpe, whose structure was investigated by X‐ray crystallography. The hydrogen‐bonded network features a number of SiO? H(H)Si and SiO? H hydrogen bridges. Evidence was found for cooperative strengthening within the sequential hydrogen bonds. Copyright © 2007 John Wiley & Sons, Ltd.     

全气相化学激光体系的直流放电研究

 为了提高化学激光体系(AGIL)中F原子的产率，采用直流放电引发方式，对棒式电极的放电特性进行了研究。在对NF3/He混合气体进行解离时，通过选择不同平衡电阻，得到了3 kW左右的放电注入功率。用光谱分析仪对F原子产率进行了测量。通过拟合计算可得：一个NF3分子能够解离出1.3～1.5个F原子。     

H原子与CO2分子碰撞的化学反应与能量转移

用时间分辨傅立叶红外发射光谱的方法对H原子与CO2分子的碰撞动力学进行了实验研究．用紫外激光光解的方法分别制备出三个不同平动能为174．7、241．0和306．2 kJ／mol的氢原子,并引发H CO2→OH CO反应．观察到了反应的产物,即振动激发的CO (v≤2)．同时也看到了在H原子与CO2分子的碰撞中发生高效的T- V能量转移．CO2的反对称伸缩模的最高振动能级为v=4．化学反应与能量转移的速率之比大约为10．     

纳米计量与原子光刻技术分析

为了说明原子光刻（Atom Lithography）在纳米计量及传递作用中的特殊地位，首先对纳米计量标准及其现状进行了简要介绍，提出纳米计量中原子光刻的基本概念和优势，结合原子光刻实验装置对原子光刻技术的工作机理进行了分析。结果表明，可以通过原子光刻技术得到纳米量级刻印条纹，为纳米计量及标准传递提供更加精确的手段。最后对常见的2种原子光刻技术——沉积型原子光刻和虚狭缝型原子光刻进行了阐述，指出2者的不同之处，为不同条件下原子光刻提供了一定的借鉴。     

Harmonic Analysis on the Compact Homogeneous Spaces──about Fourier Multiplier ofH~P（M） Space

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Formation of Fe i –B pairs in silicon at high temperatures

We report on the detection of Fe _i –B pairs in heavily B doped silicon using ⁵⁷Fe emission Mössbauer spectroscopy following implantation of radioactive ⁵⁷Mn⁺ parent ions (T _1/2?=?1.5 min) at elevated temperatures >?850 K. The Fe _i –B pairs are formed upon the dissociation of Fe _i –V pairs during the lifetime of the Mössbauer state (T _1/2?=?100 ns). The resulting free interstitial Fe_i diffuses over sufficiently large distances during the lifetime of the Mössbauer state to encounter a substitutional B impurity atom, forming Fe _i –B pairs, which are stable up to ～1,050 K on that time scale.     

Reaction of pentafluorobenzoylpyruvic acid with amines

Reactions of pentafluorobenzoylpyruvic acid with amines afford the respective enamines. The intramolecular cyclization of the latter results inN-substituted 4-quinolone-2-carboxylic acids. Ammonia and triethylamine favor the cyclization of pentafluorobenzoylpyruvic acid to 2-carboxychromone.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 299–302, February, 1994.     

硅一体化薄膜微电极器件及其应用

提出用发展中的硅微机械加工技术设计制作硅一体化薄膜微电极器件．这类微电化学器件具有微电极所特有的全部优点，而且由于结构上的一体化，便于器件整体的微型化和集成化．试用薄膜微电极器件电流法常温直接检测ＣＯ２气体，取得了满意的结果。设想通过器件三维构型设计的改进和完善，器件工作的长期稳定性可望进一步提高．