核壳型苯丙乳液的制备与交联改性研究

采用核壳聚合法制备了以聚丙烯酸丁酯为核,以聚苯乙烯和聚甲基丙烯酸甲酯为壳的软核硬壳型乳液,考察了不同的软硬单体配比、乳化剂浓度、引发剂浓度、反应温度等因素对乳液性能的影响,并探究了交联剂对乳液性能影响。通过单因素分析,确定各因素最佳组成,软硬单体比例为BA／St／MMA=15：6：4,甲基丙烯酸占单体总质量的5％,乳化剂占单体总质量的3％,阴离子型／非离子型乳化剂的比例为1：1,引发剂占单体总质量的0．5％,交联剂N-羟甲基丙烯酰胺占单体总质量的0．6％。     

Do sports help students stay away from misbehavior,suspension, or dropout?

This paper explores whether high-school sports are functional and accessible activities to keep students from school disciplinary behaviors. For this purpose, we included students racial and linguistic status, socioeconomic status, sex, and prior academic performance with the school’s proportion of free-lunch recipients and minorities, to understand how sport participation affects students of diverse groups. Additionally, the study implemented a multilevel mediation modeling to the Education Longitudinal Study (ELS) data and assessed student dropouts with sequential mediators of sport participation, school misbehavior, and suspension. The findings of the study largely revealed that White students participated in sports more than Black, Hispanic, and Asian. Likewise, students who speak English as the primary language and male students participated in sports more than their counterparts. White sport participants displayed fewer incidents of suspension than White non-sport participants. Black, Hispanic, and White sport participants had lower dropout incidents than their non-sport-participating counterparts.     

超声波对醋酸乙烯乳液（VAC）聚合的影响（英文）

对比了醋酸乙烯（VAC）在传统聚合中和超声波辅助聚合中的单体转化率和乳液粒径分布的差别。在VAC聚合过程中外加超声波环境，单体转化率从92.5 %提高到98.8%，乳液粒子平均粒径从136.7nm减小到101.4nm。在超声波辅助VAC乳液聚合中，研究了引发剂浓度和反应温度对单体转化率及乳液粒径分布的影响。试验结果表明仅靠超声波产生的自由基不足以引发聚合反应，引发剂分解产生的自由基在引发聚合过程中起着重要的作用。简单介绍了超声波辅助乳液聚合的机理，超声波可以连续提供自由基，而这些自由基的作用是使死聚合物链变的有活性，导致单体具有较高的转化率。     

聚丙烯腈合成工艺技改方案

就我国技贸结合建设的五套干法腈纶装置中聚丙烯腈合成工艺设计存在的缺陷提出改造意见,以消除操作不便、耗能高的弊端。     

建筑涂料用纯丙乳液的研制

采用甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为软硬单体组分，加入少量的自交联单体α-甲基丙烯酸(α-M从)，利用核壳乳液聚合方法制备了一种高固含量的纯丙乳液。讨论了软硬单体的配比、乳化剂种类、各种乳化剂间的配比、引发剂用量等对乳液性能及外观的影响。     

反原子转移自由基聚合的研究——AIBN/CuCl_2/bpy引发St聚合

在原子活性自由基聚合中 ,St可用引发剂 (AIBN)通过一种新的方法成功聚合 .此反应首先在 6 0℃持续10hr,然后在 10 0℃聚合 .我们在引发体系中 ,使用不同摩尔比的AIBN和CuCl2 对此进行试验 ,实验结果说明此种聚合方法引发效率高 ,易于控制 ,所得产物分子量分布窄 ,一般情况下Mw/Mn =1.36 .     

Control method for semi-active suspension based on virtual prototype

1 Introduction 1 Semi-active suspension is advantaged by good performance and low price over the passive suspension and active suspension [1]. The control strategy as the core of a control system is widely researched in practice. The simple dynamic model is often adopted in the typical process. However, the differences between the practical and physical models bring on more idealization and less practicability. On the other hand, the mechanical designer and the controls designer use different…     

Polymerization of methyl methacrylate with ethylene bridged heterodinuclear metallocene of samarium and titanium-study on synergism and kinetics

Comparison of MMA polymerization results with samarocene chloride, titanocene chloride and the title heterodinuclear (Sm−Ti) catalyst, respectively, showed synergism in the Sm-Ligand-Ti system, which obviously influenced the polymerization behaviors, for example, of yeilding higher activity and higher molecular weight polymer. Kinetic studies on polymerization of MMA with ethylene bridged samarocene and titanocene chloride/Al(i-Bu)₃ showed that the polymerization rate was first-order on the catalyst concentration, and 1.9-order on the monomer. The overall activation energy measured was 52.8 kJ/mol. Project supported by NSFC (No. 20074028), and SINOPEC(X598037).     

The Role of the School District in Student Discipline: Building Consensus in Cincinnati

The problem of student discipline disproportionately affects urban schools with large numbers of low income and ethnic minority students. Research over the past 35 years however has consistently shown that discipline policies that are understood and accepted by teachers, students, and parents and consistently enforced by school officials, correlate with lower levels of student disruption. The important role that urban school districts can play in building consensus in support of student discipline policies has not been well documented. But increased levels of student mobility in large urban areas, and increased diversity among the families served by urban districts, highlight the need for district-wide codes of behavior that provide schools with a range of discipline programs that serve the needs of their particular communities. The purpose of this article is to demonstrate how the process of developing and implementing a district-wide code of student behavior in Cincinnati played an important role in reducing disruptive behaviors leading to student suspension and expulsion. By involving all stakeholders in the development of its policies, and by responding to the concerns of all stakeholders in the range of programs it offered, the Cincinnati Public Schools was able to build consensus across socioeconomic and ethnic lines and make its code of behavior effective. On the basis of the evidence presented, it is argued that urban school districts can play a more active role in the area of student discipline. By developing and implementing district-wide codes of behavior that are understood and accepted by teachers, students, and parents, and consistently enforced by school officials, urban districts can lay the foundation on which schools can build healthy learning communities. Dr. Lionel H. Brown holds Bachelors, Masters, and Doctoral degrees from the University of Cincinnati. Dr. Brown is retired from the Cincinnati Public Schools (CPS) where he served as a teacher, vice-principal, principal, and Deputy Superintendent. His responsibilities in the role of CPS Deputy Superintendent included the Department of Curriculum and Instruction, the Office of Student Discipline, and the Office of Student Affairs. Dr. Brown is currently an Assistant Professor in the Division of Educational Studies, College of Education, Criminal Justice, and Human Services, University of Cincinnati, Cincinnati, Ohio. His research and teaching interests include urban education, alternative education, and programs for Black males.Dr. Kelvin S. Beckett holds Bachelors and Masters degrees from the University of British Columbia, Canada and a Doctoral degree from the University of London, United Kingdom. He is an Adjunct Lecturer in the Division of Educational Studies, College of Education, Criminal Justice, and Human Services, University of Cincinnati, Cincinnati, Ohio. His teaching and research interests include urban education and alternative education.     

四连杆式独立悬架运动学分析与优化

建立了四连杆式悬架多刚体系统模型，并对车轮定位参数等特性进行了仿真，运用多目标函数的最优化方法对悬架的结构参数进行了优化，将优化前后的车轮定位参数运动学特性进行了对比，结果表明，悬架结构参数的优化对提高悬架性能具有重要作用。