煤焦油蒸馏的新产品-改质沥青的生产

论述了利用热缩聚方法对中温沥青进行改质处理来生产改质沥青 ,提高了沥青的软化点、β树脂含量及结焦值 ;并介绍了生产工艺的特点、主要工艺参数及产品的质量     

用加权余量法计算球形催化剂的有效因子

本文利用加权余量法计算了等温球形催化剂的有效因子,并对催化反应n=1,2的两种情况与其它简化法进行了比较.文中取Dirac函数作为权函数,形式简单,在袖珍计算器上就能完成计算.其结果:当n=1时,与解析解非常接近;当n=2时,优于其它三种简化解法,很接近数值解.     

A rheological model for iron oxide suspensions

We have examined the rheological properties of a Co-adsorbed γ-Fe₂O₃ magnetic suspension with polyurethane (PU) as a binder and methyl ethyl ketone (MEK) or cyclohexanone (CH) as a solvent. A Haake RV20 viscometer was used to measure the suspension viscosity and the vane method was adopted to determine the fluid yield stress. A rheological model which can be viewed as a combination of the Casson model and the Bingham model is proposed to describe the suspension viscosity. The effects of temperature, particle content, and binder concentration are included in the model.     

An evaluation of commercial nickel catalysts during hydrogenation of soybean oil

The activities of several commercial nickel catalysts were determined by measuring their activation energies. Among these catalysts, G95E, Resan 22, Nysosel 222 and 325, all with low activation energy, were more active than DM3 and G95H, which had higher activation energy. However, the less active catalysts increased the linoleate selectivity of soybean oil during hydrogenation. The yields of bothtrans isomers and winterized oil were higher for the more selectively hydrogenated oil catalyzed by the less active catalysts. In the sensory evaluation, the fractionated solid fat that contained moretrans isomers was lower in flavor scores than the fractionated liquid oil after hydrogenation and winterization of soybean oil.     

Effects of Stearic Acid on the Injection Molding of Alumina

This research investigated the influence of stearic acid on the injection molding of alumina, by varying the concentration of stearic acid. The interaction between stearic acid and alumina was identified using transmission infrared spectroscopy, indicating stearic acid preferentially adsorbed onto the alumina powder surface. In addition to slightly modifying the intrinsic binder viscosity, stearic acid adsorbed onto the powder surface changed the flow behavior of the mixtures from dilatant flow to pseudoplastic flow at low temperatures. As a result, inhomogeneous distribution of binder in the injection-molded parts was minimized with increased stearic acid concentration. However, the possibility of forming bubbles in the mixtures arising from vaporization of stearic acid was enhanced. Additionally, the binder burnout temperature range was broadened with the increase of stearic acid concentration.     

枯草杆菌碱性磷酸酶制备的最佳工艺条件及酶促反应动力学性质的研究

以枯草杆菌为菌种液体培养制备碱性磷酸酶，研究确定了培养的最佳工艺条件，并对碱性磷酸酶的酶促反应动力学性质进行了初步探讨。结果表明，枯草杆菌制备碱性磷酸酶的最佳工艺条件为：40℃，pH值7．4振荡培养10h，酶活最高。对碱性磷酸酶的动力学性质研究表明，该酶催化底物磷酸苯二钠水解反应的最适pH值8．8，最适温度52℃，米氏常数Km值为2．94mmol／L。     

磷石膏的微量组分及其对水泥凝结、水化和硬化的影响

借助差热分析、热失重、X射线衍射和扫描电镜等测试手段,分析了磷石膏的微量组分,研究了磷石膏对硅酸盐水泥物理性能及水化过程和水化产物的影响,进而探讨了磷石膏对水泥单矿物的水化作用机理。     

The effect of radical desorption on the particle size distribution in vinyl acetate emulsion polymerization

The effect of free radical desorption is studied by using a mathematical model of particle size distribution in continuous emulsion polymerization. By comparing the theoretical prediction with experimental data, the value of D_o for the vinyl acetate (VAc) system is best chosen as 0.19 × 10^?7 cm²/h. The effect of radical desorption as well as mean residence time on the absolute particle size distribution, total concentration of polymer particles, conversion, and average number of radicals per polymer particle are analyzed by the model proposed.     

Gel formation in diimide‐hydrogenated polymers

The hydrogenation of diene‐based polymers via diimide is a very attractive alternative to the conventional catalytic hydrogenation route based on gaseous molecular hydrogen. However, serious crosslinking always accompanies it and limits the end‐use properties of the polymers. Gel formation in polymers that are hydrogenated via diimide has been investigated in detail through an inspection of all the chemical reactions involved in the process. The results indicate that hydrogen peroxide decomposition, some reactions related to oxygen, and the redox reaction between hydrogen peroxide and hydrazine are capable of generating radicals. However, radicals generated in the aqueous phase do not appear to initiate the crosslinking of diene‐based polymers in the latex form. It is proposed that the primary radicals giving rise to crosslinking are generated in the polymer phase in situ, and the step responsible for generating these organic radicals is possibly the diimide disproportionation reaction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1122–1125, 2005