双功能受阻胺光稳定剂GW-540与紫外线吸收剂并用效应的研究

本文用IR、UV、SEM等方法,研究了双功能基受阻胺光稳定剂——三(1,2,2,6,6-五甲基-4-哌啶基)亚磷酸酯(GW-540),与紫外线吸收剂UV-531、UV-327并用时对聚丙烯的防光作用,结果表明:GW-540-UV-531并用体系有良好的防光作用,呈强的协同效应;GW-540-UV-327并用体系呈弱的对抗作用。结果还表明:GW-540对531和327的光分解均有保护作用.电镜研究表明,加入GW-540后,使UV-327在聚丙烯中分散更不均匀,从而影响其效率的发挥。文中提出了两个体系的协同和对抗作用机理。     

Effects of Four Different Drying Methods on the Quality Characteristics of Peeled Litchis (Litchi chinensis Sonn.)

Four different drying methods, namely, air drying (AD), microwave-assisted vacuum drying (MWVD), coupled microwave–hot air drying (MWAD), and freeze drying (FD), were studied, in terms of drying time, color, reducing sugar content, shrinkage, microstructure, and sensory evaluation. The drying rate of MWVD and MWAD were notably faster than that of AD and FD. The highest reducing sugar content was observed in MWAD, followed by MWVD. No significant differences were observed in reducing sugar between air-dried and freeze-dried products. FD had the best color and shrinkage among the other drying methods. The color and shrinkage of MWVD drying is close to the fresh litchis and much better than hot air and MWAD. Scanning electron microscopy (SEM) images showed that the MWVD and FD litchis have a porous structure, whereas AD and MWAD litchis have a compact structure. The sensory evaluation suggests that peeled litchis dried by the four studied drying methods are of a quality that is accepted by consumers.     

水喷雾灭火及低倍数泡沫灭火系统在油罐消防的应用

介绍油罐区设置固定式水喷雾消防冷却水系统及固定式低倍数泡沫灭火系统,并简述水消防系统选择、水雾喷头及空气泡沫产生器的选型、布置、系统环形供水管布置和油罐区消防供水等问题。     

氨基酰化酶拆分制备手性蛋氨酸工艺条件研究

以N-乙酰DL-蛋氨酸(N-Ac-DL-Met)为拆分底物,对氨基酰化酶法拆分工艺参数如反应温度、pH、激活剂Co2 浓度以及底物浓度等因素进行了初步考察。结果表明,在反应温度37℃,缓冲体系pH7.5,Co2 浓度为0.5 mmol/L,初始底物N-Ac-DL-Met的浓度为0.06 mol/L,氨基酰化酶加入量为5μg/mL的较佳条件下,L-蛋氨酸(L-Met)的产率可达45%;产物L-Met结晶的光学纯度(用对映体过量值%e.e表示)为95.4%。实验中首次采用多组分标准曲线法,提高了茚三酮显色法在氨基酰化酶法拆分制备手性氨基酸的检测精确度     

苯直接羟基化制苯酚的技术进展

介绍了以N2O、O2以及H2O2为氧化剂，苯直接羟基化制备苯酚的技术进展，并提出了其今后的发展方向。     

铁-氧电池法预处理头孢类抗生素生产废水

用铁-氧电池,对含有高浓度有机物的头孢类抗生素生产废水进行预处理试验,研究了若干因素对其COD去除率和可生化性的影响.结果表明:对于含有高浓度有机物的头孢类抗生素生产废水,该法是十分有效的预处理手段,COD去除率可达73%,废水由难生化转变为易生化,BOD5/COD由0.22提高到了0.53.     

Study on monomer reactivity ratios of acrylonitrile/itaconic acid in aqueous deposited copolymerization system initiated by ammonium persulfate

A single water-soluble initiator-ammonium persulfate (APS), not containing alkali metal ions, was first utilized to initiate copolymerization of acrylonitrile (AN)/itaconic acid (IA) in aqueous deposited copolymerization system. Monomer reactivity ratios of this polymerization system were investigated using element analysis method and Q–e schemes. It was found that the monomer reactivity ratios of AN/IA calculated from Q–e schemes are 0.505 (r _AN) and 1.928 (r _IA), while the monomer reactivity ratios of AN/IA in aqueous deposited copolymerization system at 60 °C are 0.64 (r _AN) and 1.37 (r _IA) calculated from Kelen–Tüdõs method, 0.61 (r _AN) and 1.47 (r _IA) from Fineman–Ross method. The three pairs of monomer reactivity ratios are in good agreement. With the increase of the polymerization temperature, the monomer reactivity ratios of AN and IA approach to unity, indicating that the aqueous deposited copolymerization of AN/IA has a tendency to ideal copolymerization. At lower polymerization conversion, the monomer reactivity ratios of AN and IA have hardly any changes. When the polymerization conversion is more than 5%, the monomer reactivity ratio of AN increases, while that of IA decreases.     

中药废水的Fenton法处理试验

中药废水成分复杂、有机物含量高、色度深、生物毒性性大,其处理是工业废水难点之一。研究了Fentoni法处理中药废水的实验过程,分析了反应时间、H2O2、Fe2＋及H2O2与Fe2＋的浓度比不同条件对处理效果的影响。     

热镀铝锌钢板辊压成形后表面发黑原因分析

采用场发射扫描电镜及其配备的能谱仪,并结合钝化膜单位面积质量和表面粗糙度检测,对热镀铝锌方管表面发黑的原因进行了分析。结果表明：热镀铝锌钢板在辊压过程中外力较大,对钝化膜的破坏性较强,钝化膜因此而变薄,失去保护作用,甚至方管表面部分钝化膜脱落而露出铝锌镀层,加工过程中产生的摩擦热使镀层发生氧化,且钢板与模具摩擦造成钝化膜分布不均匀,产生色差,导致镀铝锌方管发黑。     

丙烯酸β-羟丙酯/乙烯基吡咯烷酮共聚物及其水凝胶的合成和温敏行为的研究

用自由基共聚法合成了一系列 β-羟丙酯 (β-HPAT)和乙烯基吡咯烷酮 (NVP)的共聚物及其水凝胶。发现共聚物的水溶液有敏锐的温敏行为 ,最低汇溶温度 (LCST)随 NVP含量的增加而升高 ,随着反应单体总浓度的增加 ,相变敏锐性下降且 LCST也随之下降。通过考察水凝胶的溶胀率 (SR) ,发现共聚凝胶在适当的单体浓度、交联剂浓度和较宽的单体浓度配比范围内 ,有较灵敏的温敏行为