Molecular species in liquid carboxylic acids

Measurements of dielectric permittivity and electric conductance are presented for mixtures of carboxylic acids — formic, trifluoroacetic, acetic and propionic — and non-polar liquids. For the dielectric and associative behavior of carboxylic acids a knowledge of the cis—trans conformational equilibria of the monomeric acid molecules seems to be essential. Therefore the cis and trans conformations of these molecules have been calculated by the CNDO/2 and PCILO methods. Appreciable rotational barriers for their interconversion have been obtained.     

二氧化碳速冻喷射器的优化设计及实验研究

本文在文献［３］的基础上作了优化计算的改进，利用气固两相流［１］和系统的优化计算模型编制程序，从最佳面积比、喷射个数和套筒尺寸之间的紧密联系出发，获得了优化设计速冻喷射系统的方法，用于设计速冻系统的套筒、喷嘴的结构尺寸。本文还将理论计算结果与试验数据进行比较，获得了满意的结果。     

超声溶栓

超声溶栓长期为人们所重点研究。本文对超声溶栓技术进行了综述，着重介绍和分析了其发展历史、溶栓机理、技术特点和研究现状，最后对以后的研究工作提出了一些看法。     

一维链状配位聚合物[Cd{5-(NO2)sal}2(2,2'-bipy)]n的合成与晶体结构

A coordination polymer of [Cd{5-(NO2)sal}2(2,2'-bipy)]n (5-(NO2)sal=5-nitrosalicylate, 2,2'-bipy=2,2'-bipyridine) was synthesized by hydrothermal reaction and characterized by elemental analysis, IR and X-raydiffraction single crystal structure analysis. The title complex crystallizes in monoelinic with space group C2/c, a=2.730 8(16) nm, b=1.272 3(5) nm, c=0.674 5(3) nm,β=96.73(2)°, V=2.327(2) nm3, Z=4, R=0.022 2, wR=0.057.The 5-nitrosalicylate anions doubly bridge the Cd(Ⅱ) atoms to form one-dimensional polymeric chain with therepeated eight-membered ring units (Cd-O-C-O)2. The crystal structure is stabilized by intra- and interchainhydrogen bonds interactions.     

时频域独立元分析方法实现超声兰姆波的多模式分离

为方便兰姆波信号分析与模式定征,提出一种将短时傅里叶变换(Short-Time Fourier Transform,STFT)与独立元分析(Independent Component Analysis,ICA)相结合的多模式超声兰姆波识别方法.首先通过STFT将兰姆波时域信号投影至时频域,基于各模式信号在时频域相对独立...     

2-羟基-1-萘甲醛缩氨基胍铜配合物的合成及表征

铜是生物体内必需的微量元素,是一些重要酶的活性中心,其配合物不仅在生命体系有着特殊的生物活性[1],而且由于具有特殊的磁学、电学、光学等性质而在材料、催化等许多领域中表现出潜在应用价值,因而成为人们关注的热点课题之一[2],为此我们合成了2-羟基-1-萘甲醛缩氨基胍铜配合物,并对此配合物进行了一系列表征.