反相微乳液中疏水缔合型聚丙烯酰胺的合成及其性能研究

在反相微乳液体系中合成了疏水缔合型聚丙烯酰胺 (HAPAM ) ,用Brookfield旋转粘度计测定了其水溶液性能 ,并与传统胶束聚合法制备的HAPAM作了比较 .结果显示 ,前者有更优越的耐盐和抗剪切性能 ,这主要是因为前者的大分子链上疏水共聚单体呈无规分布而后者呈嵌段分布 ,其疏水分子链以分子间而不是分子内缔合为主     

K-型卡拉胶/聚乙烯吡咯烷酮共混水凝胶的辐射合成

采用辐射技术合成了K 型卡拉胶 (KC) /聚乙烯吡咯烷酮 (PVP)共混水凝胶 ,研究了天然高分子KC、单体N 乙烯基吡咯烷酮 (N VP)、交联剂二甲基丙烯酸十四甘醇酯 ( 1 4G) ,辐照剂量以及剂量率等对辐射合成的KC/PVP共混水凝胶性质的影响 .实验发现 ,KC与适当比例的N VP共混后在一定剂量范围内辐照可得到高强度、高溶胀行为的KC/PVP共混水凝胶 ,随着共混凝胶内KC含量的相对增加 ,凝胶强度及溶胀性的能均显著提高 ,但合成该共混凝胶的最佳剂量却相对提前 ;加入 1 4G后降低了KC/PVP共混凝胶辐射合成最佳剂量 ,同时使KC/PVP共混凝胶的强度进一步提高 ;剂量、剂量率对KC/PVP共混凝胶的性质亦有很大的影响 .分析表明 ,KC与N VP共混后 ,在较低剂量下KC的降解被抑制 ,从而获得一种由物理交联的KC和化学交联的PVP形成的互穿网络 (IPN)凝胶     

信息光学实验器件与实验技巧

对半导体激光器用于全息记录的特性进行了实验研究 ,指出了半导体激光器的优点及在光学全息领域应用的巨大潜力 ;分析了三种傅立叶变换透镜的共性和差别 ,提出了会聚光中傅立叶变换透镜的优点和光学设计的基本规律 ,实验证明了所设计的实例有良好的结果。     

乳化法-FAAS法测定奶茶粉中的钙

本文采用乳化法将奶茶粉样品用乳化剂OP乳化成分散均匀且稳定的乳浊液，直接喷入空气－乙炔火焰中，以标准加入法测定钙含量。测定结果与灰化法一致，检出限0.021μg·mL^-1，RSD小于2.84%，方法简便、快速、准确。     

Teflon hierarchical nanopillars with dry and wet adhesive properties

The superior material properties of β‐keratin along with the hierarchical high‐aspect‐ratio structure of geckos' foot pad have enabled geckos to stick readily and rapidly to almost any surfaces in both dry and wet conditions. In this research, nonsticky fluoropolymer (Teflon AF) resembling β‐keratin rigidity and having an extremely low surface energy and dielectric constant was applied to fabricate a novel dry adhesive consisting of high‐aspect‐ratio nanopillars terminated with a “fluffy” top layer. Both the nanopillars and the terminating layer are fabricated concurrently by replica molding using a nanoporous anodic aluminum oxide membrane as the mold. These Teflon AF hierarchical nanostructures are shown to have an exceptional capacity to generate strong adhesion in both dry conditions and under water because of combined actions of van der Waals forces, electrostatic attractions, and hydrophobic effects. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

RECORDING INFRARED SPECTRA AT LOW SIGNAL LEVELS

Abstract

It appears that many people are under the impression that it is not possible to record meaningful infrared spectra of samples which are almost “black,” i.e., samples which cause the radiation reaching the instrument's detector to be less than a few per cent of the radiation of the unattenuated source. We have, however, been working quite successfully with samples of this nature for a number of years, using commercially available instruments to record transmission and emission spectra with signals of very low intensity. It consequently seems useful to point out that unmodified, commercial research-quality spectrophotometers are capable of better performance than is generally realized. The purpose of this review is, then, to show what can be studied under such poor signal conditions and how this is done, and to describe some of the difficulties and effects that may be encountered.     

ChemInform Abstract: Azidopentazole is Probably the Lowest-Energy N8 Species - A Theoretical Study.

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