高分子材料光老化研究方法综述

高分子材料的光老化试验已日趋成熟,但试验后材料性能的分析方法还在不断完善。将从高分子材料光老化机理、试验方法、试验后宏微观性能分析方法等方面梳理现在的研究进展,并指出进一步的研究方向,为相关从业者提供参考。     

载钴活性焦对As(V)的吸附性能与去除效果

使用沉淀负载法制备了载钴活性焦,并研究了溶液pH值、反应时间、As(V)初始浓度以及共存阴离子等对载钴活性焦吸附去除水环境中As(V)的影响。结果表明,(1)载钴后活性焦的比表面积和孔容积分别提高了20.87%和43.47%;(2)载钴活性焦对As(V)最佳吸附pH值为4.0,当As(V)的初始浓度为10 mg/L时,As(V)去除率可达97%;(3)吸附过程符合准二级动力学模型(k2=0.66,R2=0.96),吸附等温线为Freundlich型(kF=8.227,1/n=0.396,R2=0.97);(4)稳定性实验验证了载钴活性焦的稳定性,钴不易脱附,最大脱附率仅为0.145%。     

纳米SiO2在含阴离子表面活性剂低浊水处理中的应用

在含有阴离子表面活性剂-十二烷基硫酸钠(SDS)的6 NTU高岭土悬浊液中,改变SDS的浓度,投加纳米SiO2与聚合铝PAC进行动态混凝实验与静沉实验,借助图像分析技术与分形理论,探讨了纳米SiO2与PAC处理含SDS低浊水的作用机理、絮凝效果与形态学特征.结果表明:①纳米SiO2与SDS使高岭土粒子表面负电性增强.纳米SiO2的絮凝机理以吸附架桥为主.②纳米SiO2对SDS的去除效果优于PAC.SDS浓度越高,去除效果越显著.但纳米SiO2对无机高岭土粒子的处理能力不如PAC,PAC絮凝后的上清液浊度低.当SDS浓度增至10 mg/L时,纳米SiO2对SDS的去除率高,而PAC对SDS的絮凝能力弱,PAC对无机颗粒的去除效果也下降.③助凝剂纳米SiO2较强的吸附活性能加快PAC絮体成长为结构密实的RLCA构型,分维值高,絮凝效果好.     

植被混凝土抗侵蚀性能研究

基材的抗侵蚀性能是生态护坡成功的关键因素之一。通过设计的实验装置对3组不同边坡进行了侵蚀实验,探讨了植被混凝土的抗侵蚀机理,比较了3种边坡的抗侵蚀性能。实验表明:植被混凝土生态防护边坡具有良好的抗侵蚀性能,在同等条件下无植被防护土质边坡的坡面侵蚀速率比有植被防护土质边坡的坡面侵蚀速率高出两个数量级。     

上海PRED系统的演变与发展战略研究

人口、资源、环境与发展的协调,是一研究内容宽泛而又复杂的课题,也是可持续发展的实质性内容。自８０年代以来,ＰＲＥＤ始终是我国区域研究的热点之一。本文在已有研究的基础上,首次以ＰＲＥＤ系统发 时间轨迹为线索,对上海１９７８－１９９５年这一具有特殊历史意义的时期中有关ＰＲＥＤ大量数据进行了分析。     

中国沿海风暴潮灾害的历史变化及未来趋向

中国是全球少数几个同时受台风风暴潮和温带风暴潮危害的国家之一,风暴潮灾一年四季,从面到北均可发生,本文基于中国沿海近５０年风暴潮灾时间变化和空间分布特点的分析,着重探讨了近５００年全国及长江、黄河、珠江三角洲的历史记录和近５０年实测风暴潮灾发生频次的变化及其与气候波动的关系,并对未来全球变化背景下,中国沿海风暴潮灾的变化趋向进行了讨论。结果表明：近５００年来,中国沿海的风暴潮灾的气温较高的偏暖时段     

软泥夹层对香港软土场地地震反应的影响

选择了香港有代表性的８个典型场地,通过钻探、现场剪切波速测量和土样动力实验建立了场地的分析模型,用２１次地震的１２８条基岩地震动记录作为,计算了场地土层地震反应,结果表明,对带海泥软夹层的砂质回填土场地,地震动的长周期分量（１．２～１．５s）被显著放大了,现有抗震规范的设计反应谱不能反映这类场地的反应特性,基于计算结果,提出了分别适合有、无软夹层场地的归－化设计反应谱。     

Biodegradability of Chemically Modified Starch (RS4)/PVA Blend Films: Part 2

Biodegradable films were successfully prepared by using cornstarch (CS), chemically modified starch (RS4), polyvinyl alcohol (PVA), glycerol (GL), and citric acid (CA). The physical properties and biodegradability of the films using CS, RS4, and additives were investigated. The results of the investigation revealed that the RS4-added film was better than the CS-added film in tensile strength (TS), elongation at break (%E), swelling behavior (SB) and solubility (S). Especially, the RS4/PVA blend film with CA as an additive showed physical properties superior to other films. Furthermore, when the film was dried at low temperature, the properties of the films clearly improved because the hydrogen bonding was activated at low temperature. The biodegradation of films was carried out using the enzymatic, microbiological and soil burial test. The enzyme used in this study was amyloglucosidase (AMG), α-amylase (α-AM) and β-amylase (β-AM). At the enzymatic degradation test, the GL-added films had an approximately 60% degradation, while the CA-added films were degraded about 25%. The low degradation value on CA-added film is attributed to low pH of film added CA that deactivated the enzymatic reaction. The microbiological degradation teat was performed by using Bacillus subtilis and Aspergillus niger.     

Natural Weathering of Polypropylene and Waste Tire Dust (PP/WTD) Blends

Three series of polypropylene and waste tire dust (PP/WTD) blends using three different WTD sizes were prepared, compression-molded and cut into dumbbells. The specimens were exposed to natural weathering in the northern part of Malaysia for a period of 6 months. The results show that at the same blend composition, blends with fine WTD size exhibit higher mechanical properties than that of blends with coarse WTD after exposure to natural weathering. Regardless of WTD size, the retention of tensile strength and elongation at break, E_b increases with the increase in WTD content. From the exposed surface morphology, it is apparent that the blends with fine WTD and WTD-rich blends were able to withstand weathering better than blends with coarse WTD and PP-rich blends. The DSC thermograms suggest that the overall drop in melting temperature (T_m) of the exposed blends decreases as the WTD content increases.     

生态补水对艾里克湖环境变化的重要意义

以艾里克湖为主要研究对象,论述了艾里克湖生态补水前后区域生态环境演变,并对生态补水产生的生态环境效益及社会经济效益进行分析。说明干旱区水资源的开发利用一定要优先保护生态环境。