环氧树脂对环氧模塑料(EMC)的性能影响分析

在环氧模塑料中,环氧树脂是环氧模塑料的基体树脂,也是环氧模塑料的主要原材料,起着将其他组分交联结合到一起的重要作用。环氧树脂作为环氧模塑料的胶粘剂,具有粘合性高、固化收缩率小、耐化学介质稳定性好、电绝缘性优良、工艺性能良好等特点。因此环氧树脂类型的选择及其性能对环氧模塑料的性能都有很大的影响。文章简单介绍了环氧树脂的分类、结构、作用及特点,主要探讨了不同结构环氧树脂对环氧模塑料的粘接性、稳定性、收缩率、电性能及机械性能等的影响。     

Identifying model pollutants to investigate biodegradation of hazardous XOCs in WWTPs

Xenobiotic organic compounds (XOCs) in wastewater treatment plant (WWTP) effluents might cause toxic effects in ecosystems. Several investigations have emphasized biodegradation as an important removal mechanism to reduce pollution with XOCs from WWTP effluents. The aim of the study was to design a screening tool to identify and select hazardous model pollutants for the further investigation of biodegradation in WWTPs. The screening tool consists of three criteria: The XOC is present in WWTP effluents, the XOC constitutes an intolerable risk in drinking water or the environment, and the XOC is expected to be biodegradable in WWTPs. The screening tool was tested on bisphenol A (BPA), carbamazepine (CBZ), di(2ethylhexyl)-phthalate (DEHP), 17beta-estradiol (E2), estrone (E1), 17alpha-ethinyloetradiol (EE2), ibuprofen, naproxen, nonylphenol (NP), and octylphenol (OP). BPA, DEHP, E2, E1, EE2, and NP passed all criteria in the screening tool and were selected as model pollutants. OP did not pass the filter and was rejected as model pollutant. CBZ, ibuprofen, and naproxen were not finally evaluated due to insufficient data.     

水中微塑料污染及转化去除的研究进展

阐述了微塑料的来源、分布以及迁移转化过程,分析评价了微塑料的毒性效应,探讨了混凝、高级氧化及膜生物反应器技术去除微塑料的研究进展。通过论述,揭示水环境中微塑料对生态系统造成的潜在风险以及对人类健康的威胁,提出目前微塑料去除技术的优势和不足,并为今后微塑料的研究做出建议和展望。     

有机氯化物光催化反应动力学的研究

以五氯酚钠和氯代愈创木酚为目标物，在TiO2悬浮体系中对它们的暗吸附和紫外光催化氧化行为进行了研究，考察吸附和动力学的关系。实验表明，固体催化剂与溶液中组分的吸附在20min内可以达到平衡，消除了光催化过程中吸附外扩散对反应速率的影响，得出了吸附平衡常数。研究了悬浮体系光催化反应的影响因素。获得了相关参数与反应速率间的定量关系。在实验基础上提出了有机氯化物光催化降解的动力学模型。     

Purification, characterization, and steady-state kinetics of a meta-cleavage compound hydrolase from Pseudomonas fluorescens IPO1

2-Hydroxy-6-oxo-7-methylocta-2,4-dienoate (6-isopropyl-HODA) hydrolase (CumD), an enzyme of the cumene biodegradation pathway encoded by the cumD gene of Pseudomonas fluorescens IP01, was purified to homogeneity from an overexpressing Escherichia coli strain. SDS-polyacrylamide gel electrophoresis and gel filtration demonstrated that it is a dimeric enzyme with a subunit molecular mass of 32 kDa. The pH optima for activity and stability were 8.0 and 7.0-9.0, respectively. The enzyme exhibited a biphasic Arrhenius plot of catalysis with two characteristic energies of activation with a break point at 20 degrees C. The enzyme has a K(m) of 7.3 microM and a k(cat) of 21 s(-1) for 6-isopropyl-HODA (150 mM phosphate, pH 7.5, 25 degrees C), and its substrate specificity covers larger C6 substituents compared with another monoalkylbenzene hydrolase, TodR Unlike TodF, CumD could slightly hydrolyze 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate (6-phenyl-HODA). A mutant enzyme as to a putative active site residue, S103A, had 10(5)-fold lower activity than that of the wild-type enzyme.     

Multiple Mass Transfers of Small Volatile Molecules Through Flexible Food Packaging

This article deals with evolution of packed foodstuff quality with time of storage. The transport of small volatile molecules (flavor compounds, water vapor, and gases) into and through flexible food packaging materials is reviewed, as well as their multiple transfers. Sorption, diffusion, and permeation phenomena are distinguished. Transport properties are largely determined by packaging characteristics, flavor molecules properties, food matrix composition, and environmental conditions. Transfer of small volatile molecules into and through food packaging materials can modify food quality and properties of the packaging materials, thus possibly altering packed foodstuff shelflife. More research is required on transport of flavor molecules through packaging materials by considering liquid and solid food matrices flavored with mixtures of aroma compounds at more realistic concentrations; interactions of aroma compounds with food matrices, and with packaging being followed during storage in given environmental conditions.     

豆腐柴中有效成分复合分离提取研究

试验以豆腐柴叶为原料，采用复合分离提取工艺，提取叶中的蛋白质和果胶产品。首先通过不同溶剂提取蛋白质，得到碱溶性蛋白质〉水溶性蛋白质〉醇溶性蛋白质〉盐溶性蛋白质的结论；并对提取蛋白质后的上清液和滤渣进行了提取果胶的最佳条件和参数的确立，进行了萃取果胶时的萃取液种类、pH和盐析果胶时的盐的用量的单因素实验，又以萃取时的温度、pH、时间和料液比四个因素四个水平进行了正交试验，得到如下结论：从豆腐柴叶中复合提取分离蛋白质和果胶的最佳提取工岂条件：以盐溶液作为复合提取剂较为理想，果胶提取分离的最佳条件为萃取温度90℃、溶液pH值4、萃取时间95min、料液比l：45，在此条件下豆腐柴叶果胶的产量为22％，同时可得到0．15％的蛋白质。     

秸秆氨化后生物技术处理的工艺

以最佳条件氨化处理后的玉米秸秆为原料,通过对菌种的诱变筛选、固体培养基的组合实验及发酵工艺条件优化等,确定质量分数为70%氨化秸秆末、20%的麸皮与15%的鲜酒糟配料比,采用黑曲霉(经处理)与面包酵母菌种比质量分数为1∶1,经32℃、28h通气发酵,可使蛋白质含量大幅度提高,并获得较满意的植酸酶、酸性蛋白酶、淀粉糖化酶酶活,具有推广应用价值.     

有机氯化物动态光催化反应器数学模型

根据光催化反应的特点,采用工业常用的管式圆柱(环)型反应器,建立外循环悬浮态光催化反应器系统。以氯代愈创木酚光催化降解为例,采用中心有限差分法对模型进行离散化,并用积分追赶法、四阶龙格-库塔单步积分法进行计算;用Matlab软件进行微分方程的求解。再用Origin软件描绘出反应器内光强分布和浓度分布的三维立体图。结果表明,紫外光强的辐射随着径向远离光源而逐渐减弱;反应器中无因次浓度分布沿着轴向(水流方向)逐渐降低,沿径向(远离光源方向)浓度逐渐增大。     

环糊精在纺织染整加工中应用的新进展

环糊精作为一种环保型助剂，越来越被染整研究者所重视。介绍了环糊精的结构和性质以及包合客体分子的机理；同时介绍了环糊精在染色、后整理、水洗以及印染废水处理中应用的新进展。