The dynamic mechanical analysis,impact, and morphological studies of EPDM–PVC and MMA‐g‐EPDM–PVC blends

The dynamic mechanical studies, impact resistance, and scanning electron microscopic studies of ethylene propylene diene terpolymer–poly(vinyl chloride) (EPDM–PVC) and methyl methacrylate grafted EPDM rubber (MMA‐g‐EPDM)–PVC (graft contents of 4, 13, 21, and 32%) blends were undertaken. All the regions of viscoelasticity were present in the E′ curve, while the E″ curve showed two glass transition temperatures for EPDM–PVC and MMA‐g‐EPDM–PVC blends, and the T_g increased with increasing graft content, indicating the incompatibility of these blends. The tan δ curve showed three dispersion regions for all blends arising from the α, β, and Γ transitions of the molecules. The sharp α transition peak shifted to higher temperatures with increasing concentration of the graft copolymer in the blends. EPDM showed less improvement while a sixfold increase in impact strength was noticed with the grafted EPDM. The scanning electron microscopy micrographs of EPDM–PVC showed less interaction between the phases in comparison to MMA‐g‐EPDM–PVC blends. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1959–1968, 1999     

磁化除垢影响因素作用规律及其数学模型研究

在交变磁场作用下对碳酸钙进行除垢的影响因素较多,为研究磁场条件下不同工艺因素对碳酸钙结垢的影响规律,研究采用正交方法对饱和碳酸钙溶液进行了磁化试验处理,结果表明：磁化时间和初始钙离子浓度为影响磁化除垢的最显著因素,当磁化时间为0.5 h、电流频率为0.6 kHz、线圈匝数为100圈、c₀（Ca²⁺）为1 000 mg/L、波形为方波时,该条件下磁化溶液的电导率平均值为1.474 mS/cm,与未磁化碳酸钙溶液相比,其电导率增加了0.147 mS/cm,电导率可增加11.45个百分点,除垢效果良好。研究通过回归分析方法建立的磁化除垢作用规律数学模型,可为提高管路的磁化除垢效率提供一定的理论依据,也对工业冷却水系统的除垢问题有重要的参考意义。     

冻结间冷却设备的选配与布置

冻结间是冷冻（冷藏）企业生产环节中的重要组成部分,性能如何,不仅关系产品质量,也对能耗产生直接影响。合理选配、布置冻结间冷却设备,是提高冻结间性能的重要手段。本文就冻结间冷却设备选配和布置的基本方式进行论述。     

聚氨酯硬质泡沫塑料的处理和回收利用

随着聚氨酯工业的迅速发展,大量的聚氨酯废弃物需要回收利用。介绍了废旧聚氨酯硬质泡沫塑料的处理及回收方法,主要包括其物理回收、化学回收、焚烧等处理方法的技术原理,以及国内外的发展和应用现状。     

Self‐reinforcing elastomer composites based on ethylene–propylene–diene monomer rubber and liquid‐crystalline polymer

In this study, the prime factor determining the size, shape, and distribution of liquid‐crystalline polymer (LCP) was the viscosity ratio at the processing conditions. The fiber‐forming capacity of the LCP depended on the viscosity of the ethylene–propylene–diene monomer rubber (EPDM). With increasing LCP content, the tensile and tear strengths did not increase, perhaps because of incompatibility between the EPDM and LCP. The hardness increased because of the hard mesogenic groups in the LCP. The percentage swelling decreased as the LCP content increased. With increasing LCP content, processability became easier because of a lower melt viscosity. The scorch time increased at higher LCP levels. A higher percentage crystallinity was observed with increasing LCP content. Scanning electron microscopy clearly showed the fiber phase formation, which was two‐dimensionally isotropic in nature, confirming fiber formation even in a shear field. The addition of LCP improved the thermal stability. The onset degradation temperatures shifted to higher values with increasing LCP content. Dynamic mechanical thermal analysis revealed that with the addition of LCP, the mechanical damping increased at its lower level. High‐temperature processing increased the effective amorphous zone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 711–718, 2004     

大学最忧郁的与最急切的

中国大学取得了很多成就，但问题也不少，真正想持续健康发展，还是多看看问题为好。许多问题中，最严重的因而最令人忧郁的是行政权力的蔓延不仅未得到控制，而且还在延续并恶化。学术腐败渗透到各个方面，权学交易日益盛行，权力配置教育资源加剧了情况的恶化，大学年轻学者学术兴趣的转移，大学精神受到极恶劣的损毁，这一切，最主要的责任承担者应是目前更加彰显的行政化体制，更加强化了不良机制。最急切的问题在于大学体制的改革。     

活性碳-Fenton联用技术处理实验室高浓度废水

针对实验室废水,采用活性碳联合Fenton试剂氧化处理,探讨主要因素对COD处理效果的影响.实验结果表明,活性碳在添加量为0.45 g/mL,反应30 min后对废水中COD的去除率达61.32％;Fenton试剂在H2O2添加量为0.07 mg/mL,FeSO4·7H2O的添加量为0.02 g/mL的条件下反应60 min后,对废水中COD的去除率达到59.88％;将活性碳吸附和Fenton试剂联合作用后,活性碳添加量减少了0.05 g/mL,FeSO4·7H2O添加量减少了0.005 g/mL,去除率可达89.23％,显著提高实验室废水中COD的去除率.     

Maternity leave, women's employment, and marital incompatibility.

This research investigated the relationship between the length of women's maternity leave and marital incompatibility, in the context of other variables including the woman's employment, her dissatisfaction with the division of household labor, and her sense of role overload. Length of leave, work hours, and family salience were associated with several forms of dissatisfaction, which in turn predicted role overload. Role overload predicted increased marital incompatibility for experienced mothers but did not for first-time mothers, for whom discrepancies between preferred and actual child care were more important. Length of maternity leave showed significant interactions with other variables, supporting the hypothesis that a short leave is a risk factor that, when combined with another risk factor, contributes to personal and marital distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

配电网馈线自动化故障处理模式的比较及优化

馈线自动化的故障处理是配电自动化的重要功能。对目前的馈线自动化模式进行了分类、比较和分析 ,评述了其优缺点和适应场合 ;在综合各种模式的基础上 ,提出了最优馈线自动化故障处理模式