负载型磷钨酸催化杂醇油合成混合酯的研究

本实验以杂醇油和乙酸为原料，杂多酸HPW／MxOy为催化剂。在相同条件下将几种工艺进行比较，从而选出适合该酯化反应的工艺。同时考察了催化剂的用量、醇酸酯比、反应时间等对酯化反应的影响。并研究了杂多酸的重复使用性。确定了酯化率和酯含量最佳时的酯合成反应的工艺条件。     

电除尘器分电场灰密度变化规律及粉煤灰密度与成份的关系

本文介绍粉煤灰经电除尘器分离后所得分电场灰密度沿电场方向的变化规律及影响因素，并阐述了粉煤灰密度与成份之间的关系。     

脱硫石膏粉煤灰胶结材水化硬化机理及耐水性研究

以火电厂的两种废渣即脱硫石膏和粉煤灰为主要原料制得的胶结材，其强度明显高于普通石膏制品，软化系数大于０．８５。采用水化热测定、ＸＲＤ和ｐＨ值测定及ＳＥＭ／ＥＤＸＡ分析，并结合宏观试验结果，分析了这种胶结材的水化硬化机理和微结构特点，并对其耐水性提高的原因进行了讨论。     

Simple and economic syntheses of some (Z)-7- and (Z)-9-alkenyl acetates,and of (E,Z)-7,9-dodecadien-1-yl acetate,the sex pheromone of the European grapevine moth,using aleuritic acid as a common starting material

Short syntheses of (Z)-7-dodecen-1-yl acetate, (Z)-7-tetradecen-1-yl acetate, (Z)-9-dodecen-1-yl acetate, and (Z)-9-tetradecen-1-yl acetate from 7-hydroxyheptanal and 9-oxononanoic acid precursors obtained by oxidative cleavage of easily available aleuritic acid are reported. The key step in these syntheses is a stereoselective Wittig reaction between aldehyde and alkyl-phosphonium salt. Wittig-Horner type reaction of 7-hydroxyheptanal and diethyl cyanomethylphosphonate gave the ,-unsaturated nitrile derivative which after protection of the hydroxyl group was reduced to the corresponding aldehyde. Wittig reaction of the latter, followed by acetylation, completed the synthesis of (E,Z)-7,9-dodecadien-1-yl acetate, the sex pheromone of the European grapevine mothLobesia botrana Schiff.     

高分子量聚氯乙烯树脂增塑,填充体系的物理力学性能研究

本文研究聚合度及增塑剂、填充剂用量对高分子量聚氯乙烯（ＨＭＷＰＶＣ）树脂物理力学性能的影响规律，并将国内外ＨＭＷＰＶＣ树脂以及ＨＭＷＰＶＣ与通用型ＰＶＣ树脂进行了性能对比。结果表明，ＨＭＷＰＶＣ增塑、填充体系的拉什强度、撕裂强度冲击回弹性及压缩永久形变等物理力学性能均随聚合度的提高而有所增加，而且各项性能均优于通用型ＰＶＣ树脂，可有效地用作橡胶代用品。分子量相同的国内外ＨＭＷＰＶＣ树脂物理力学性能基本相同。但是，后者随着增塑剂用量的增加，弹性比前者有所提高；随着填充剂用量的增加，性能变化比前者缓慢．增加填充剂用量以降低制品的体积成本。笔者还时两者物理力学性能的差异与颗粒形态之间的关系进行了探讨。     

An Experimental Investigation of Lime Juice Drying in a Pilot Plant Spray Dryer

One of the major problems in spray drying of fruit juices such as lime juice is stickiness and thermoplasticity of their compositions. Lime juice consists of invert sugars and citric acid, which have low glass transition temperatures. Due to this characteristic, the particles stick on the dryer wall upon their collision with it. As a result, drying of these materials is very difficult. In order to solve this problem, various percent of silicon dioxide and maltodextrin (DE5), based on total soluble solid content of lime juice, have been used to reach a suitable drying condition. A cool chamber wall spray dryer was used in this investigation in order to decrease the probability of particles stickiness on the wall. Our investigation revealed that an addition of 10% silicon dioxide and 20% maltodextrin (DE5) to lime juice is the optimum amount for a complete and successful drying of lime juice. Sampling of particles from different longitudinal distances in the dryer tower is carried out to find the particle moisture contents as they fly downward in the dryer. The results show a very fast decrease in entrance moisture contents. Based on our experimental data, the variation of moisture contents are presented as a function of radial distance from central line and longitudinal distance from the entrance region.     

网络社会信息安全保障技术研究

网络社会作为一种新型社会形态,是现实社会在网络空间中的延伸和反映,是随着信息技术不断发展而形成的一种新的社会形态。新信息技术的快速发展和普及,使其面临的信息安全问题也愈加突出。在对当前网络社会信息安全面临的问题和常用的安全保障技术分析的基础上,提出对网络进行网格化,并以网格为基础构建防护、监控和响应集成一体式技术保障体系,该方法可以把各网络的安全技术融合为一个整体来保障网络社会的的信息安全,实现协同防控的目的。     

浅谈C语言中循环结构的教学--回答好循环结构的“三个问题”

循环结构是C语言程序设计中的重难点,其掌握情况对于后续章节的学习效果尤为关键。本文以什么是循环、何时需要使用循环以及如何使用循环三个问题为主线,通过精心选择的教学案例和灵活有效的教学方法来进行解答,以激发学生兴趣,培养编程思想。     

Trans FA and solid fat contents of margarines marketed in Turkey

Trans FA (TFA), solid fat contents (SFC), and slip melting points of 12 different tub and stick margarines marketed in Turkey were examined in this study. No trans isomers were found in four margarines, which suggests they were formulated from interesterified or blended fats and oils. The products with no TFA generally had more short-chain saturated FA, which suggests coconut oil-based oil components. TFA content of the other 10 products varied from 7.7 to 37.8%. Compared to the products formulated in North America, Turkish margarines contain more TFA and have higher SFC.     

Influence of fly ash and its mean particle size on certain engineering properties of cement composite mortars

An experimental investigation on the effects of incorporating large volumes of fly ash on the early engineering properties and long-term strength of masonry mortars is reported. The effect of fly ash and its mean particle size (PD) on the variation of workability and strength has been studied. It was found that fly ash and its mean particle size play a very significant role on the strength of masonry mortars. It has been observed that the early-term strength, except the mortars incorporating coarse fly ash (CFA), was slightly influenced by the replacement with fly ash. The long-term strength (both the bond strength and the compressive strength) will significantly increase, especially for the bond strength of mortars incorporating coarse fly ash. It was also found that the bond strength significantly increased as the mean particle size of fly ash decreases after 28 days curing. However, the 7-day strength was little influenced by fly ash particle size. The fluidity of composite mortar enhanced due to replace cement and lime with fly ash, and the mean PD of fly ash significantly influenced the workability.