Atom transfer radical polymerization of 6‐O‐methacryloyl‐1,2;3,4‐di‐O‐isopropylidene‐D‐galactopyranose in solution

A detailed exploration of the atom transfer radical polymerization (ATRP) of a sugar‐carrying monomer, 6‐O‐methacryloyl‐1,2;3,4‐di‐O‐isopropylidene‐D‐galactopyranose (MAIPGal) was performed. The factors pertinent to ATRP, such as initiators, ligands, catalysts, and temperature were optimized to obtain good control over the polymerization. The kinetics were examined in detail when the polymerization was initiated by methyl 2‐bromoisopropionate (2‐MBP), ethyl 2‐bromoisobutyrate (2‐EBiB), or a macroinitiator, [α‐(2‐bromoisobutyrylate)‐ω‐methyl PEO] (PEO–Br), with bipyridine (bipy) as the ligand at 60 °C or by 2‐EiBB with N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) as the ligand at room temperature (23 °C). The effects of the catalysts (CuBr and CuCl) were also investigated. We demonstrate that the successful ATRP of MAIPGal can be achieved for 2‐EBiB/CuBr/bipy and 2‐MBP/CuCl/bipy at 60 °C and for 2‐EBiB/CuBr/PMDETA at room temperature. The initiation by 2‐EBiB at room temperature with PMDETA as the ligand should be the most optimum operation for its moderate condition and suppression of many side reactions. Chain extension of P(MAIPGal) prepared by ATRP with methyl methacrylate (MMA) as the second monomer was carried out and a diblock copolymer, P(MAIPGal)‐b‐PMMA, was obtained. Functional polymers, poly(D‐galactose 6‐methacrylate) (PGMA), PEO‐b‐PGMA, and PGMA‐b‐PMMA were obtained after removal of the protecting groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 752–762, 2005     

光学偏振玻璃的发展

光学偏振玻璃大约是 15年前研制和开发出来的 ,投入市场后 ,以其优异的性能在偏振片领域独占一方 ,尤其是在光纤传感器和高性能大屏幕液晶显示领域 ,光学偏振玻璃占据了主导产品的地位。详细综述了光学偏振玻璃的发展历史、基本原理和结构、生产工艺以及产品性能 ,并指出了存在的问题和发展方向     

First Synthesis of Mosquito Larvicidal Butenolides I and II

ＩｎｔｒｏｄｕｃｔｉｏｎＶｅｒｙｒｅｃｅｎｔｌｙ ,ｔｗｏｎｅｗｍｏｓｑｕｉｔｏｌａｒｖｉｃｉｄａｌｂｕｔｅｎｏ ｌｉｄｅｓＩ (1)ａｎｄＩＩ (2 )ｗｅｒｅｉｓｏｌａｔｅｄｂｙＫａｒｕｎａｒａｔｎｅｅｔａｌ.1ｆｒｏｍｔｈｅｌｅａｖｅｓｏｆａｌｌｔｈｒｅｅｓｐｅｃｉｅｓｏｆＨｏｒｔｏｎｉａ (ｆａｍ ｉｌｙＭｏｎｉｍｉａｃｅａｅ) (Ｈ .ａｎｇｕｓｔｉｆｏｌｉａ ,Ｈ .ｆｌｏｒｉｂｕｎｄａａｎｄＨ .ｏｖａｌｉｆｏｌｉａ) .Ｂｏｔｈｂｕｔｅｎｏｌｉｄｅｓｅｘｈｉｂｉｔｅｄｍｏｓｑｕｉｔｏｌａｒ ｖｉｃｉｄａｌａｃｔ…     

Crystal Structure of Octaethyloxyphthalocyaninato Copper,the Overlap Affect on the Ring Skeleton Distortion

The crystal structure of 1,4,8,11,15,18,22,25‐octaethyloxyphthalocyaninatocopper was determined by X‐ray diffraction. The ring skeleton distortion is shown, which not only attributed to inter‐molecular steric congestion of substituents but also to the less overlap of the skeletons.     

基于子带位平面容错算法的应用

在研究容错图像编码算法的基础上，针对图像压缩编码中复杂度较大和将图像分成多个小块而带来的图像重建中有分块痕迹等问题，在子带位平面编码（SBC）算法中加入了与图像无关的率失真优化编码并采用虚拟分块的方法，对SBC算法进行了改进，实验结果表明，在相同压缩倍数和相同误码率情况下，本算法与传统的图像压缩算法重建图像的峰值信噪比提高了1．0～1．5dB。     

无限差集类及其应用

若S为Z+的一无限子集,称S-S={n-m|n,m∈S,n>m}为一无限差集.本文研究Z+的子集族F生成的无限差集类(?)F-△={S-S|S∈F)及其对偶族K(?)F-△的性质,并讨论它们在动力系统研究中的应用.     

CONVERGENCE OF INEXACT CONIC NEWTON METHODS

A conic Newton method is attractive because it converges to a local minimizzer rapidly from any sufficiently good initial guess. However, it may be expensive to solve the conic Newton equation at each iterate. In this paper we consider an inexact conic Newton method, which solves the couic Newton equation oldy approximately and in sonm unspecified manner. Furthermore, we show that such method is locally convergent and characterizes the order of convergence in terms of the rate of convergence of the relative residuals.     

Crystallographic report: Tri(p‐fluorobenzyl)tin N‐methylpiperazinyldithiocarbamate

The tin atom is a distorted trigonal bipyramid geometry defined by sulfur donors derived from the asymmetrically binding dithiocarbamate ligand and three ipso‐carbon atoms from the p‐fluorobenzyl substituents. Copyright © 2004 John Wiley & Sons, Ltd.     

Crystallographic report: Di(p‐chlorobenzyl)tin bis(N‐methylpiperazinyldithiocarbamate)

The tin atom in (4‐Cl‐C₆H₄CH₂)₂Sn[S₂CN(CH₂CH₂)₂NCH₃]₂ is in a C₂S₄ skew‐trapezoidal bipyramidal geometry with the two carbon atoms being disposed over the weaker Sn? S bonds. Copyright © 2005 John Wiley & Sons, Ltd.     

Local bootstrap

The local bootstrap method draws bootstrap samples from a neighborhood of each data point. Unlike the common bootstrap, it is especially useful for heteroscedastic data. This paper considers local bootstrap of y for a data set {(x _i , y _i )} with the neighborhood defined by the window in a kernel regression model. It shows that for each x, the bootstrap distribution and moments converge almost surely to the true distribution and moments of y respectively, and this convergence is also uniform in x within the data set.