阳离子水性聚氨酯涂层的制备与性能研究

以聚己内酯二醇（PCL）、异佛尔酮二异氰酸酯（IPDI）、二甘醇（DEG）、丙烯酸-2-羟乙酯（HEA）、N-甲基二乙醇胺（MDEA）为主要原料,合成了应用于马口铁的阳离子水性聚氨酯（CWPU）涂层。探究了不同异氰酸根指数（R值）、MDEA与PCL物质的量之比改变对CWPU涂层性能的影响。通过热重分析（TG）、吸水率、差示扫描量热分析（DSC）、硬度以及耐水性能等对CWPU涂层进行表征,探究了软硬段比例变化和亲水基团含量不同对涂层性能的影响。研究结果表明：MDEA与PCL的物质的量之比不变的情况下,R值为1.8时,CWPU涂层的吸水率最低,综合性能相对较佳;固定R值不变为1.8,随着MDEA与PCL的物质的量之比的增大,CWPU乳液的储存稳定性整体良好,CWPU涂层的硬度逐渐增大,耐水性和热分解温度均呈现先上升后减小的趋势,粒径呈现先下降后增大的趋势;当R值为1.8、n(MDEA)∶n(PCL)为3.47∶1时,CWPU涂层的综合性能较好。     

长江上游社会经济因子对侵蚀产沙的影响

In recent years, the role of human activities in changing sediment yield has become more apparent for the construction of hydraulic engineering and water conservation projec-tions in the Upper Yangtze River, but it has not been evaluated at the macro scale. Taking Sichuan Province and Chongqing City as an example, this paper studies the relationship between socio-economic factors and sediment yield in the Upper Yangtze River based on section data in 1989 and 2007. The results show that sediment yield is significantly correlated with population density and cultivated area, in which the former appears to be more closely related to sediment yield. Moreover, in the relation of sediment yield vs. population density, a critical value of population density exists, below which the sediment yield increases with the increase of population density and over which the sediment yield increases with the decrease of population density. The phenomenon essentially reflects the influence of natural factors,such as topography, precipitation and soil property, and some human activities on sediment yield. The region with a higher population density than critical value is located in the east of the study area and is characterized by plains, hills and low mountains, whereas the opposite is located in the west and characterized by middle and high mountains. In the eastern region,more people live on the lands with a low slope where regional soil erosion is slight; therefore,sediment yield is negatively related with population density. In contrast, in the western region,the population tends to aggregate in the areas with abundant soil and water resources which usually lead to a higher intensity of natural erosion, and in tum, high-intensity agricultural practices in these areas may further strengthen local soil erosion. It is also found that popu-lation tends to move from the areas with bad environment and high sediment yield to the areas with more comfortable environment and less sediment yield. The natural factors have greater influence on sediment yield of western region than that of eastern region. Generally,the natural factors play a dominant role on sediment yield in the Upper Yangtze River.     

A newly combined code-designing method of two-dimensional signature codes for OCDMA system

A new kind of two-dimensional optical orthogonal code named ESPC/OCS is constructed, which uses the extend square prime code （ESPC） for time spreading and the one-coincidence sequence（OCS） for wavelength hopping. The performance of ESPC/OCS is analyzed and the mean value of cross-correlation is deduced. Meanwhile the bit error ratio （BER） for codes is simulated and compared. The simulation results show that given p and q, the BER of ESPC/OCS is reduced, and the capacity is enlarged, when the number of hopping codes p is increased. Given OCS （given q and d）, when p is changed, only the capacity is changed, but the BER is almost the same. The performance of ESPC/OCS is better than that of PC/ OCS.     

壳聚糖浓度对改性无纺布草莓包装保鲜效果的影响

以质量分数为1.0%,1.5%和2.0%的壳聚糖保鲜液对定量为12.7 g/m2的无纺布进行改性,研究不同质量分数壳聚糖改性的无纺布包装对草莓保鲜效果的影响。研究结果表明,在室温条件下,改性无纺布对草莓的保鲜效果均优于未改性无纺布的,其中,以质量分数为1.5%的壳聚糖保鲜液改性无纺布包装的草莓,其保鲜效果最好,在储藏期内,其感官变化较小,失重率较低,储藏3 d后的硬度为0.95 kg/cm2,色差平均值为6.995 NBS,可溶性固形物含量在贮藏后期呈现出上升趋势。     

我国炼钢固废利用现状与发展趋势

党中央、国务院历来高度重视固废资源利用工作,把资源综合利用作为经济和社会发展中的一项长远战略方针和重大技术经济政策。特别是党的十八大以来,将资源综合利用作为发展循环经济的重要内涵纳入生态文明建设,推动各项工作取得了长足进步。整体来看,我国炼钢固废产量增长较快,以内部循环和堆存为主,有效的综合利用和应用相对较少,产品附加值不高,综合利用率较低。未来,在钢铁工业高质量发展的驱动下,绿色发展将成为钢铁企业发展的本质要求,炼钢固废的综合利用水平也将会快速提高。     

基于D_时刻表算法的大学课程表的求解

根据现在大学编排课表的特点设计了一种全新的方法,即用时间规划中的D_时刻表算法来对课程表进行编排。这是以文献[2]的求解D_时刻表的方法为基础,参照近年来人们多采用的遗传算法,加以改进的方法。结果表明该方法具有一定的可行性和有效性。     

中国铁合金行业固废资源化利用技术展望

我国是铁合金生产和消费大国,近年来铁合金行业工艺装备水平有所提高,节能降本技术取得明显进步,但仍面临矿产资源对外依存度高、环保压力加大等问题。文章在总结我国铁合金行业生产运营现状及面临形势的基础上,重点梳理铁合金行业固废利用情况,并提出铁合金行业及其固废高效利用技术的发展建议。     

基于社会生态城市主义的可持续校园研究——斯德哥尔摩市阿尔巴诺校园

可持续校园理念在校园规划中越来越被重视。斯德哥尔摩阿尔巴诺校园是基于全新可持续理念的城市更新项目,建成后将成为由20世纪老工业区蜕变而成的三大教育机构共享的城市核心科学城。其中校园规划设计和管理的核心可持续发展理念——社会生态城市主义,是由跨界团队基于阿尔巴诺校园现状开创的一种新范式,整合诸多生态理论并结合城市化现状,以求在理论和实施层面指导阿尔巴诺校园的建设。通过实地考察、对话访谈、文献研究等方法,阐释了社会生态城市主义的内涵和该项目对社会生态城市主义的运用。作为可持续校园的典范,该项目提供了一个可供参考的全新理念,其可持续策略和具体实施手法为国内可持续校园规划提供重要的参考和借鉴意义。     

二次法制备冶金渣陶瓷-微晶玻璃复合材料

为了改善钢渣陶瓷的外观颜色和表面性能,采用二次烧成法制备出了钢渣陶瓷-高炉渣微晶玻璃复合材料,并对其结构与性能关系进行了研究。陶瓷层主晶相为辉石相,微晶玻璃层主晶相是辉石相和黄长石相。在陶瓷1220℃烧结温度,微晶玻璃880℃析晶温度的最佳条件下,复合材料耐磨性能显著提高,其磨损体积比单体材料降低1倍以上。陶瓷-微晶玻璃紧密结合的过渡层以及微晶玻璃析晶均匀和增加的辉石相有利于复合材料表面性能的改善。     

道路非点源污染研究进展

随着城市化进程的加快,公路总量的持续增长以及汽车拥有量的迅速增大,道路非点源污染问题将会日益突出.本文从路面沉积物的污染特性、路面径流污染特征以及道路非点源污染的控制措施三个方面,介绍了道路非点源污染的研究进展.