水性涂料用聚丙烯酸酯微乳液的合成及其表征

低污染、低能耗的乳液涂料在建筑涂料中得到了广泛应用,具有核壳结构的聚合物乳液对胶膜的力学性能有较大的改善[1],微米(或纳米)级乳液具有优异的成膜性能,两者均是近年来高分子材料科学中发展十分迅速的新领域[2]。但微乳液聚合时乳化剂用量大,单体含量少。本文采用阴非离子复合乳化剂体系,单体预乳化工艺,种子乳液聚合法,通过正交实验优化聚合工艺参数及体系配方,合成了纳米级聚丙烯酸酯微乳液。并对乳液聚合物的粒径及分布、热性能、分子量及分布、结构等进行了表征。1　实验部分1 1　主要原料及乳液表征苯乙烯(St)、甲基丙烯酸甲…     

离子液体催化合成乙二醇丁醚醋酸酯

以乙二醇单丁醚和冰醋酸为原料,在离子液体N-甲基吡咯烷酮硫酸氢盐([Hnmp] HSO4)催化下,合成了乙二醇丁醚醋酸酯.考察了催化剂用量、物料配比、反应时间、带水剂等因素对反应收率的影响.利用气相色谱仪分析了产物的纯度;利用核磁共振谱仪和质谱仪表征了产物的结构.结果表明,合成产物的纯度大于99.0％.[Hnmp]H ...     

新型塑料管材加工方法研究进展

塑料管材综合性能优异,广泛应用于城乡建设的各个领域.随着管材行业的发展,对管材性能的要求也越来越高,塑料管材加工方式也在不断发展.本文说明了塑料管材应用领域,介绍了管材的挤出成型生产方法,概括了塑料管材行业现状,探讨了传统管材加工方式存在的不足,阐明了开发新型管材生产工艺的必要性和重要性,从定义、原理、结构、管材性能等...     

KINETIC STUDIES OF HAEMOPOIETIC PROGENITOR CELLS (CFU-C) AND T-LYMPHOCYTES IN THE LIVER OF HUMAN FOETUS

In the development of human foetus. liver is an important haemopoietic organ. Wehave determined the liver weight and total hepatic nucleated cells from 24 foetuses on the onehand, and CFU-C yield, total number of CFU-C and T-lymphocytes in liver from 22 foetuses ofdifferent ages on the other. From the kinetic observations through the early developmental period of the foetuses. themaximum yield of CFU-C or the total numer of CFU-C in the liver occurs at 4--5 months ofgestation; during the first 5 months of gestation the percentage of T-lymphocytes in the liveris about 1--2%.     

Geometrical Structures and Activities of Free Radical Scavenging Studies of Baicalein and Scutellarein

In order to study the free radical scavenging capacity and molecular structures of baicalein and scutellarein,the structure-activity relationship of these two molecules was analyzed.The geometric structures of the compounds were optimized by DMol3 code based on density functional theory.The theoretical parameters of the atomic charge distribution,the distribution of molecular frontier orbital,the energy difference and Fukui functions were calculated.Meantime,superoxide anion free radical and 1,1-diphenyl-2-picrylhydrazyl radical(DPPH)methods were used to determine the scavenging capacity of the compounds.The results showed that the scavenging rate of DPPH radicals and superoxide anion radicals increased with the increase of sample concentration,and had a dose-effect relationship.The radical-scavenging activities in the order of baicalein>scutellarein>BHT were showed.The p-π conjugation of the hydroxyl oxygen atom influenced the certain ability to repelling electrons in the molecular structures of baicalein and scutellarein based on the data of the atomic charge distribution,the distribution of molecular frontier orbital,the energy difference and Fukui functions.Hydroxyl groups were more susceptible to attack and exhibit free radical scavenging activity.The oxygen atom in the phenolic hydroxyl group of the molecule structure of the samples may be the reaction active sites where the electrophilic reaction occurred.These results offer useful theoretical bases for the research and application of antioxidant activities of substances containing such molecular structures.     

腹部CT对急性胰腺炎病况及预后的诊断价值

本研究通过对89例水肿型急性胰腺炎患者及31例出血坏死型急性胰腺炎患者采用64排螺旋CT进行腹部扫描检查,根据结果进行病情严重程度及预后状况的评估。根据Balthazar CT分级标准共检测出A级0例、B级42例、C级38例、D级23例、E级17例;随着CT分级的升高,急性胰腺炎患者的胰腺血流量（BF）、胰腺血容量（BV）逐渐降低,差异具有显著性（P<0.05）,但各分级之间胰腺血流量（BF）、血容量（BV）无明显差异（P>0.05）;在对急性胰腺炎患者预后判断方面,CT分级越低表明保守治疗即可痊愈,如分级呈现升高趋势则表示需同手术治疗。本研究中35例患者经手术治疗,但是在D、E级患者中有3例患者因病情严重,累及多器官功能衰竭死亡。结果证实腹部CT扫描能够准确反映急性胰腺炎患者病情严重程度,对临床治疗、预后评估具有重要的参考价值。     

爆轰试验闪光X射线照片的图像处理

 本文扼要地介绍了一种用微机图像处理系统处理爆轰试验闪光X射线照片的数字图像处理方法。我们用该方法处理了一套爆轰试验闪光X射线照片，获得了较好的结果。     

浅水中度振幅孤立波解的分支

利用平面动力系统分支方法研究浅水中度振幅方程的定性行为和孤立波解.给出了系统在不同参数条件下的相图.获得了光滑孤立波、cuspon解和周期波解的隐式表达式.对方程的光滑孤立波解、cuspon解和周期波解进行了数值模拟.获得的结果完善了相关文献已有的结果.