Gas-Filled Bubbles in Ionic Solids

A device to selectively introduce gases into a melt of KCl from which single crystals or oriented bicrystals are being pulled is described. The insoluble gases (e.g. Ar, Cl₂, N₂, and CO₂) were incorporated into the growing crystals in the form of bulk and grain boundary bubbles having a decided crystallographic appearance. The as-grown bubbles of Ar and Cl₂ were extended along the growth axis, whereas those of N₂ and CO₂ were compressed in this direction. The bubble shapes are expected to depend on surface energy considerations and on the way in which the gas interacts with the solid; the bubble geometries were qualitatively consistent with available data on the theoretical adsorption behavior of these gases on (100) crystal faces of KCl. On annealing under load, the bubbles became highly faceted. Only the very stable (100) plane developed; this indicates the extreme anisotropy of the surface energy even at temperatures approaching the melting point. The failure of bubbles to evolve completely into cubes is probably due to the difficulty of establishing growth habits normal to the (100) plane.     

双向互动电视技术及其应用

随着科技的不断深入与发展,双向互动电视技术作为一种全新的系统技术为我国广电业带来新的革新。传统数字电视的单一化模式并不能满足人们日益增长的需求,有效地攻克EPON等技术,将数据业务加以多元化改造,使得一个更加具有个性化的双向互动电视得以实现。立足于双向互动电视系统的结构与组成,来探讨双向互动电视的技术问题,从而分析其具体应用与发展。     

PRODUCTION OF N-ACETYLCHITOOLIGOSACCHARIDES BY AEROMONAS SP. DYU-TOO 7

Aeromonas sp. DYU‐Too 7 was screened to produce chitinases. The enzymes had an optimal reaction temperature of 50C and an optimal pH of 7.0. The best concentration of chitin in the fermentation process is 4%. Higher concentrations of chitin inhibited microbial growth and influenced the production of reducing sugars, the enzymatic activity and the protein content in the culture. N‐acetylglucosamine, the main product in the hydrolysate, was 0.7 g/L at 36 h of cultivation. The concentration of N‐acetylchitobiose was 0.16 g/L for the regular chitin broth and 0.28 g/L for the phosphorus‐limiting chitin broth, with the highest concentration of N‐acetylchitohexaose at about 0.062 g/L in both media. Experimental results showed that cultivation under a phosphorus‐limiting condition substantially reduced the production of biomass, chitinases as well as N‐acetylchitooligosaccharides.     

提高对数字电视故障的判断及排除能力

数字技术、网络技术、信息技术等高新技术对我国的经济、文化和社会产生了巨大的影响,数字电视作为信息领域最大的一次技术革命,极大地提高了广播电视的技术质量,数字有线电视的发展与推广是从2007年开始的,那时数字电视整体转换基本完成,之后的一年,数字有线电视逐渐被认可,并被广大群众所接受,2010年起广大用户开始大量运用数字电视,数字电视的发展进入一个新阶段。从此数字电视开始替代模拟电视,成为千家万户娱乐生活的一部分,但是随着数字电视的推广,用户在使用数字电视的过程中遇到的故障也越来越多,分析数字电视常见的一些故障,对发生故障的原因进行了研究,并提出解决的方法,总结用户自己解决故障的一般方法。