Nonisothermal crystallization kinetics: poly(ethylene terephthalate)-poly(ethylene oxide) segmented copolymer and poly(ethylene oxide) homopolymer

The nonisothermal crystallization behavior of polyethylene oxide (PEO) in poly(ethylene terephthalate)poly(ethylene oxide) (PETPEO) segmented copolymer and PEO homopolymer has been studied by means of differential scanning calorimetry, as well as transmission electron microscope. The kinetics of PEO in copolymer and PEO homopolymer under nonisothermal crystallization condition has been analyzed by Ozawa equation. The results show that Ozawa equation only describes the crystallization behavior of PEO-6000 homopolymer successfully, but fails to describe the whole crystallization process of PEO in copolymer because the secondary crystallization in the later stage could not be neglected. Due to the constraint of PET segments imposed on the PEO segments, a distinct two stage of crystallization of PEO in copolymer has been investigated by using Avrami equation modified by Jeziorny to deal with the nonisothermal crystallization data. In the case of PEO-6000 homopolymer, good linear relation for the whole crystallization process is obtained owing to the secondary crystallization does not occur under our experimental condition. (C) 2001 Elsevier Science Ltd. All rights reserved.

Structure and luminescent properties of YAG : Eu, Bi synthesized by sol-gel method

(Y1-xEux)(3)Al5O12 and (Y1-x-yEuxBiy)(3)Al5O12 were prepared by so-gel method. Their structures of the luminophor are similar to that of YAG, which is recorded on the ASTM card and belongs to a cubic system. The luminescent properties show that the reaction temperature of the current sol-gel method is in the range of 400-500 degrees C, which is lower than that of the conventional solid state reaction. The luminophors have the strongest emission intensity when the values of x and y are 0.06 and 0.013, respectively.

YAG∶Eu~(3+)、Bi~(3+)的溶胶-凝胶法合成及其结构和发光性能

溶胶－凝胶法以其各组分混合均匀性好、反应温度低、节省能源等诸多优点而引起了人们极大兴趣［１，２］．近年来，利用该法研制玻璃和陶瓷等无机材料的报道越来越多［３，４］．但研制稀土固体发光材料的报道则较少．钇铝石榴石Ｙ３Ａｌ５Ｏ１２（ＹＡＧ）是一种很好的基…

Gas transport property of homo- and copolyimides from isomeric thiaphthalic dianhydride and oxydianiline

Gas transport properties of home- and copolyimides prepared from 3,3',4,4'- and 2,2',3,3'-thiaphthalic dianhydride (p-TDPA and m-TDPA, respectively) with 4,4-oxydianiline (ODA) were investigated. The fractional free volume of m-TDPA-ODA is larger than that of p-TDPA-ODA, and the chain segmental mobility of the former is lower than that of the latter. The permeability coefficients of m-TDPA-ODA to H-2, CO2, and O-2 are more increased by 48, 69 and 75%, at 30 degrees C and 10 atm, respectively, than those of p-TDPA-ODA; but the permselectivities of m-TDPA-ODA for H-2, CO2, and O-2 toward N-2 are more decreased by 33, 77, and 26%, respectively, than those of p-TDPA-ODA. The permeability coefficients and the diffusion coefficients of the copolyimides can be described by the following equations: log P = Phi(p) log P-p + Phi(m), log P-m and log D-a = D-a = Phi(p) log(D-alpha)(p) + Phi(m) log(D-a)(m), respectively. The variation of the permselectivity is controlled predominantly by diffusivity selectivity. These observations are interpreted in terms of variations in the fractional free volume of polyimides. (C) 1997 John Wiley & Sons, Inc.

促进剂与细胞色素c中赖氨酸残基相互作用的研究

促进剂与细胞色素ｃ中赖氨酸残基相互作用的研究曲晓刚，菊，周成立，陆天虹，董绍俊（中国科学院长春应用化学研究所，电分析化学开放实验室，长春，１３００２２）关键词细胞色素ｃ，促进剂，同步荧光光谱Ｈｉｌｌ小组［１］发现４，４＇－联吡啶能促进细胞色素ｃ（ｃｙ...

黄河河口泥沙扩散及周围海区岸滩稳定性研究

本文根据历年来黄河口及邻近海域的沉积物、悬浮体调查资料（1961年3月-10月、1984年、1989年枯、洪季（笔者参加）等及海岸带调查）；1855年以来的海图资料；1975年以来逐年卫片资料及黄河口海域遥感卫片解译分析报告等资料进行了分析、整理。同时，本文进行了如下工作：（1）对黄河口海区悬浮泥沙的光谱特征进行了野外实测、室内分析；分析了黄河河水的光谱特征；（2）野外测量了莱州湾南岸海滩滩面物质光谱反射特征，对典型样品取样，分析其粒径及其与光谱反射的关系；（3）分析了自1975年以来黄河口海域的卫片，运用计算机处理CCT；（4）对1961年、1989年底怪沉积物粒度参数及粘、砂含量作了模糊数学分析；（5）对黄河三角洲古岸线、水深作了对比，并用卫片资料分析岸线（现代）的动态变化；（6）对黄河三角洲岸滩进行了模糊动态分类。本文定量分析悬浮泥沙含量与光谱反射峰值波长的关系，得出在黄河口邻近海域、悬沙含量跨度大的地区，在用卫星资料定量计算悬沙含量时，应用分段式回归方程式：在高含量区，以TM4解译较好，相反则用TM3解译为宜。本文首次在该地区用卫星遥感资料与准同步海上观察资料进行相关分析，两者相关系较高，其中以TM4尤高些。针对大气程辐射对卫星资料的影响，提出了一种简易的大气校正方法，取得较好的结果。同时，结合不同时相的卫片分析，我们对黄河口海域泥沙分布规律及其影响因素作了详细的论叙。对1961年和1989年5月两次表层底质的粒度参数及粘、砂含量等要素进行模糊分类，得出黄河泥沙扩散的主要方向在1961年时，主要向北、西北、西及东北，少量向东、东南方向扩散。1989年黄河泥沙的扩散方向主要为东北、东南、西南及向东，少量泥沙向西北沿三角洲岸滩扩散。不同时期实测泥沙分布，岸线变化及卫片的泥沙分布型式证实了上述结论。本文首次研究了莱州湾潮滩表层沉积物粒径组成与光谱反射率的定量关系，得出其最侍研究波段。对不同时期地形图的岸线，等深线、坡度变化的对比分析，得出不同岸段的变化特征。用卫片对岸线动态的定量分析表明，仅在河口等快速变化的地区以及较长时段的岸线变化情况适用，而在变化较小的岸段以及时段较短时，其计算结果误差较大。本文最后提出一种考虑多因素综合作用、并能突出主导因素的模糊动态分类，分类结果与实际情况较为吻合，它为海岸动态性的研究提出了新方向。

Sensitive and Rapid Detection of Genetic Modified Soybean (Roundup Ready) by Loop-Mediated Isothermal Amplification

Using the LAMP method, a highly specific and sensitive detection system for genetically modified soybean (Roundup Ready) was designed. In this detection system, a set of four primers was designed by targeting the exogenous 35S epsps gene. Target DNA was amplified and visualized on agarose gel within 45 min under isothermal conditions at 65 degrees C. Without gel electrophoresis, the LAMP amplicon was visualized directly in the reaction tube by the addition of SYBR Green I for naked-eye inspection. The detection sensitivity of LAMP was 10-fold higher than the nested PCR established in our laboratory. Moreover, the LAMP method was much quicker, taking only 70 min, as compared with 300 min for nested PCR to complete the analysis of the GM soybean. Compared with traditional PCR approaches, the LAMP procedure is faster and more sensitive, and there is no need for a special PCR machine or electrophoresis equipment. Hence, this method can be a very useful tool for GMO detection and is particularly convenient for fast screening.

机器人及机器人学中的控制问题

机器人已成为进一步实现制造业、非制造业、军事活动以至家庭服务自动化的重要工具.机器人学则是更综合地研究如何使机器或系统具有“思想、感知或动作功能的一门交叉性新学科”.机器人的发展是波浪式的,经历了多次的曲折.目前工业机器人中除装配机器人外,其他点焊、弧焊、喷漆及搬运机器人,由于应用范围限制,以及工业生产装备更新速度和投资规模的影响,市场日趋饱和.以美国为例.制造商订单1984年达到高峰6046台.至1986年下降至5713台,不过对机器人未来市场大都持乐观态度.但进一步开拓市场.有待于推出适用于各种环境作业的各式各样的机器人.日本东京大学教授认为机器人当前处于又一次高潮的前夜(Nightmare),正是需要大力加强研究开发的时期.我国正在着手建立工业机器人产业,这一情况值得我们注意.本文着重从研究角度来介绍当前机器人及机器人学中的控制问题的现状及主要问题.

河道砂油藏产能预测系统研究

Productivity prediction is a serious factor to oil reservoir management and working out economic plans so that it is paid great attention to all the time. Gudao Oil Field, which has been yielding more than 100 million tons of crude oil accumulatively since it was put into developing in 1970's as a complete set of oil field, now entering double extra high water-bearing period after productivity construction, stable production and depletion stage. It's main layer series of development is thought to be type of channel sand reservoir in east China. Form channel sand reservoir in upper Guantao Group of Shengli Oil Field, there are several large oil fields such as Gudao, Gudong and Chengdao etc. with almost one-third reserves of whole Shengli Oil Field. It is considered the common characteristics in this area would be that the layer is less developed, the sand distribution is sporadic, the connectivity is weak, the heterogeneity is strong in plane, the oil layer is unconsolidated with big porosity, high permeability and serious sanding, and the oil is heavy. Because of the restricted factors to productivity of this kind of reservoir, it is very significant to study the productivity prediction this kind of reservoir. By selecting the upstream fluvial reservoir in Guantao Group of Neogene system as researching object, the author studied the forecasting technology with heterogeneous reservoir. Firstly, the author constructed the 3D subtle geological model quantificationally through researching exploitation geology in the way of combination of dynamic and static methods. Secondly, by the aid of dynamic material obtained while producing, the author analyzed the oil distribution law and influencing factors, then finished dynamic oil reservoir description on the basis of static oil reservoir description. Thirdly, via comparing and analyzing all the forecasting methods of productivity existed, the author developed a set of method to forecast productivity of single well and oil field which fit to channel sand reservoir. At last, under the support of ORACLE database, with the advanced computer technology, the author programmed the software called 'Channel Sand Reservoir Prediction System'. Up to now, this system has been putting into use in Gudao Oil Field and very successful.