铜合金挤压材缩尾缺陷的控制办法

分析了铜合金制品缩尾缺陷的产生原因,并提出了相应的预防措施.有效减少缩尾缺陷,提高产品质量和经济效益.     

欧盟撤销硫丹登记对我国茶叶出口影响的分析

欧盟在对硫丹进行风险评估的基础上,于2005年5月3日和6月2日,先后发布SPS和TBT通报,撤销硫丹作为植物保护产品登记。按照欧盟相关指令的要求,硫丹在茶叶中的MRLs由30mg/kg调整为0.01mg/kg。硫丹是目前我国茶叶生产中的农药推广品种,而且欧盟是我国重要的茶叶出口市场,欧盟的此项规定对我国茶叶出口有一定的影响,应当采取措施积极应对。     

A new short-path distillation system applied to the reduction of cholesterol in butter and lard

A molecular distillation plant, built particularly to increase the separation efficiency and to obtain safer working conditions, was tested to remove cholesterol from anhydrous butter and lard. A preliminary experiment was carried out with butter to evaluate the fractionation obtained at temperatures between 190 and 250°C and residual pressures between 10⁻³ and 10⁻⁴ torr. A second experiment was carried out at 185°C and at the maximum operational vacuum, evaluating the fractionation achieved within a time scale between 30 and 180 min. Cholesterol was almost completely removed during the second hour with minimal loss of low-molecular weight triglycerides. An experiment was carried out with lard at 250°C and maximum achievable operational vacuum (10⁻⁴ Torr), lasting approximately 6 h, and cholesterol was removed almost completely during the second hour without significant modifications in the triglyceride composition. This situation remained constant throughout the duration of the test.     

建筑供排水用聚丙烯管道(PP-R)特性简析

PP -R管道具有质轻、连接方便、良好耐热性和较小导热系数、耐腐蚀且管道阻力小等优点 ,属绿色产品 ,本文对施工过程中就PP -R管与混凝土的粘结不密、抗紫外性能差等问题提出了相应的处理措施     

聚碳酸酯的热降解

综述了聚碳酸酯的热稳定性及其影响因素,并详细论述了一些添加剂如偶联剂甲基三甲氧基硅烷、钛酸四丁酯、阻燃剂二苯砜磺酸钾(KSS)、聚氨丙基苯基倍半硅氧烷(PAPSQ)等对聚碳酸酯热稳定性的影响,阐述了Kissinger法和Ozawa法等聚合物热降解动力学的分析方法。重点介绍了近期国内外有关聚碳酸酯热降解产物和热降解机理方面的研究成果。     

牛奶纤维的服用性能研究

从研究牛奶纤维的特性以及牛奶纤维织物的服用性能出发,根据牛奶纤维和其它纤维混纺后服用性能发生的变化以及不同混纺比例对牛奶纤维织物服用性能的影响发现:牛奶纤维具有较好的可纺性,其织物光滑柔软,具有良好的透气性和透湿性,很适用于内衣类及夏季类服装。但牛奶纤维织物的抗静电性能较差。     

高性能水泥基材料及其精细制品的发展

高性能水泥基材料及其精细制品已成为当代胶凝亲的重要研究方向，本文介绍了该方向理论研究与技术研究取得的主要进展，并对其涵义、研究内容及发展进行了探讨。     

我国甲烷氯化物产品成本核算规程的探讨

从核算规程修改的原理、原则及内容等方面对甲烷氯化物产品成本核算规程的修改、规范和完善情况进行了介绍。     

Quantitation of volatile compounds in heated triolein by static headspace capillary gas chromatography/infrared spectroscopy-mass spectrometry

Static headspace and capillary gas chromatography/infrared spectroscopy-mass spectrometry were used to collect, separate, identify and quantitate the oxidative and thermal decomposition products in heated triolein. Approximately 4 L of triolein was heated in a deep-fat fryer at 190°C for 12 h each day for a total of 60 h, until it contained>-20% polymeric material. The concentration of heptane and octane increased after 12 h heating, then decreased upon further heating, while the concentration of volatile aldehydes decreased gradually during heating. After 12 h of heating, the concentrations of the major volatiles changed as follows: heptane (16.36 to 30.17 ppm), octane (24.48 to 40.77 ppm), heptanal (21.68 ppm to 9.11 ppm), octanal (35.53 to 36.64 ppm), nonanal (68.95 to 43.16 ppm), (E)-2-decenal (135.00 to 89.00 ppm) and (E)-2-undecenal (88.50 to 61.00 ppm). After 60 h of heating, when the oil contained over 20% polymeric material, the concentrations of heptane, octane, heptanal, octanol, nonanal, (E)-2-decenal and (E)-2-undecenal were 5.16, 4.39, 5.45, 7.02, 18.07, 12.50 and 6.00 ppm, respectively.     

中国聚氯乙烯下游应用现状及发展趋势

介绍了当前中国聚氯乙烯行业下游总体运行状况,并从PVC管道、异型材、地板、木塑墙板、软质膜等聚氯乙烯下游产品阐述了下游制品发展现状及特点。