Monophosphorylation of cornstarch to improve its sizing properties for heat‐sensitive wool yarns at reduced temperature

Commercial cornstarch was mono‐phosphorylated to different levels of substitution in order to investigate the effect of phosphorylation on the properties of cornstarch for sizing heat‐sensitive wool yarns at reduced temperature. The influences of starch phosphorylation and sizing temperature upon apparent viscosity and viscosity stability of cooked starch paste, starch retrogradation, adhesion to wool fibers, performance of starch film, aerobic biodegradation, mechanical properties, and hairiness of sized wool yarns were evaluated. The phosphorylation level was varied from 0.021 to 0.082 in degree of substitution (DS), while the temperature considered was from 60 to 95°C. It was found that mono‐phosphorylation of starch resulted in enhanced paste stability, reduced retrogradation, strong adhesion to wool fibers, increased performances of starch film, improved mechanical properties of sized wool yarns, and decreased hairiness on surface of sized yarns even if paste temperature was lowered to 60°C. Initially increasing phosphorylation level enhanced positive effects, but excessively increasing the level was not applicable due to marked reduction in tensile strength of starch film. The phosphorylation with a DS value of 0.061 could improve the performances of cornstarch for sizing wool yarns at 60–80°C. Moreover, measurement on BOD₅/COD ratios demonstrated that the phosphorylation did not impede aerobic biodegradation of starch. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Characterization of H-FER and H-TON using temperature-programmed desorption of alkylamines

Simultaneous temperature-programmed desorption (TPD) and thermogravimetric analysis (TGA) measurements were performed with n-propylamine and isopropylamine in H-FER and H-TON in order to test whether the Brønsted-acid sites associated with the 10-ring, straight channels in H-FER could be distinguished from the acid sites in the side cavities. In H-TON, the saturation uptakes were identical for both amines, as were the acid-site densities determined from the amounts of amine which reacted to olefin and ammonia products above 600 K. By contrast, the saturation uptake for isopropylamine in H-FER was much lower than the uptake of n-propylamine and the site density determined from the amounts which react were also significantly lower. It is argued that the n-propylamine results for H-FER provide a measure of the total Brønsted-acid-site density, while the isopropylamine results provide a measure of the site density in the 10-ring channels.     

A comparison of desorption process of Chinese and Australian lignites by dynamic vapour sorption

Modified BET model and Do and Do (D.D.) model were chosen to interpret the desorption process of water on hard and soft lignites. The organic and inorganic hydrophilic sites were determined by X-ray photoelectron spectroscopy and X-Ray fluorescence spectroscopy. From the modified BET model, only a small part of hydrophilic sites (HSs) acted as effective primary sites due to space restraint, intramolecular hydrogen bond and maybe more than one hydrophilic site connecting with one water molecule. From the D.D. model, the total adsorption sites (S_t) of Loy Yang lignite (LY) is 18.7 mmol/g, which is higher than that of Shengli (SL) 17.0 mmol/g in spite of lower primary sites, and the saturation concentration of water (q_us) in the micropore of LY is 33.7 mmol/g, which is much higher than that of SL (12.5 mmol/g). So the high moisture-holding capacity of LY is mainly determined by the high S_t and q_us, and not the primary sites. The size of water clusters entering the micropores is 7 for SL and 6 for LY, which is related to relative location of HS. When dewatered, the higher total sites density and smaller water cluster size of LY both implied higher dewatering energy.     

基于配电变压器优化布点的线路降耗分析

从配电变压器布点的两极限位置入手,分析了配电变压器不同布置时的线损情况。介绍了配电变压器优化布点位置的确定方法,以及相关降损布点的其他问题。分析得出,采用多台配电变压器负荷中心供电,可最大幅度降低低压电网的线损。     

有关继电保护的INTERNET网址扫描

介绍了Internet网上有关继电保护专业的网址及网络查询办法 ,并对有关站点进行了简要描述 ,以便通过上网 ,充分利用互联网的信息资源 ,提高工作效率。     

小麦面筋蛋白的磷酸化改性研究

用正交试验法对小麦面筋蛋白进行磷酸化改性的工艺条件优选。结果表明 ,在三聚磷酸钠与小麦面筋蛋白之比为 3∶1 0、反应时间为 0 5h、反应温度为 2 0℃及反应pH值为 1 0 0的最佳条件下制备的磷酸化小麦面筋蛋白功能特性有大幅度提高     

Gel Polymer Electrolyte with Anion‐Trapping Boron Moieties via One‐Step Synthesis for Symmetrical Supercapacitors

A novel gel polymer electrolyte (GPE) which is based on new synthesized boron‐containing monomer, benzyl methacrylate, 1 m LiClO₄/N,N‐dimethylformamidel liquid electrolyte solution is prepared through a one‐step synthesis method. The boron‐containing GPE (B‐GPE) not only displays excellent mechanical behavior, favorable thermal stability, but also exhibits an outstanding ionic conductivity of 2.33 mS cm^?1 at room temperature owing to the presence of anion‐trapping boron sites. The lithium ion transference in this gel polymer film at ambient temperature is 0.60. Furthermore, the symmetrical supercapacitor which is fabricated with B‐GPE as electrolyte and reduced graphene oxide as electrode demonstrates a broad potential window of 2.3 V. The specific capacitance of symmetrical B‐GPE supercapacitors retains 90% after 3000 charge–discharge cycles at current density of 1 A g^?1.     

酸性材料在CVOCs催化氧化中的应用

含氯挥发性有机化合物(CVOCs)对环境安全和人类健康存在持久性污染和危害。催化氧化法具有操作温度低和CO_2选择性高等优点,被广泛应用于CVOCs催化降解。催化剂作为CVOCs催化降解过程的核心部分,受到很多学者的关注。分析酸性分子筛、金属改性分子筛和复合氧化物酸性材料对各种CVOCs催化氧化活性、副产物控制性能、CO_2和HCl选择性的影响。结果表明,催化剂表面酸中心、氧化中心和催化剂表面结构性质在CVOCs催化氧化过程中起重要作用。较多酸中心和较大比表面积有利于CVOCs分子的吸附和活化,提高HCl选择性。而较多氧化中心则有利于CVOCs深度氧化,减少副产物产生,提高CO_2选择性。     

响应面优化烟叶多糖磷酸化工艺 及保润性评价

采用超声辅助提取烟叶多糖,在单因素基础上,以响应面法优化磷酸化烟叶多糖的工艺条件,再分别以磷酸化烟叶多糖、烟叶多糖、蒸馏水和丙二醇为保润剂,对比其在烟丝上的持水性能,最后,对烟叶多糖和磷酸化烟叶多糖进行评吸。结果表明:制备磷酸化烟叶多糖的最佳工艺条件为:反应时间6.1 h、反应温度95℃、pH=9.0,磷酸化烟叶多糖中磷酸根质量分数平均为11.68%。持水性能大小为磷酸化烟叶多糖烟叶多糖丙二醇蒸馏水。感官评价结果显示:添加磷酸化烟叶多糖对改善卷烟评吸品质效果显著。