国内外AE／AES生产现状及市场分析

介绍国内外脂肪醇聚氧乙烯醚(AE)和脂肪醇聚氧乙烯醚硫酸盐(AES)的生产现状及供需情况.2003年全球AE的总产能为391.7万t/a,总产量为155.8万t,总消费量为148.3万t;AES的总产能为377.5万t/a,产量约为300万t,消费量约为90万t.2004年我国AE的产能已超过50万t/a,但产量只有15万t,消费量为30.5万t;AES的总产能为37.95万t/a,产量为14万t,市场需求约10万t.最后补充介绍乙氧基化的技术进展.     

In vitro comparison of hepatic metabolism of 9cis-11 trans and 10trans-12cis isomers of CLA in the rat

Hepatic metabolism of the two main isomers of CLA (9cis-11 trans, 10trans-12cisC_18∶2) was compared to that of oleic acid (representative of the main plasma FA) in 16 rats by using the in vitro method of incubated liver slices. Liver tissue samples were incubated at 37°C for 17h under an atmosphere of 95% O₂/5%CO₂ in a medium supplemented with 0.75 mM of FA mixture (representative of circulating nonesterified FA) and with 55 μM [1-¹⁴C]9cis-11 trans C_18∶2, [1-¹⁴C]10trans-12cis C_18∶2, or [1-¹⁴C]oleate. The uptake of CLA by hepatocytes was similar for both isomers (9%) and was three times higher (P<0.01) than for oleate (2.6%). The rate of CLA isomer oxidation was two times higher (49 and 40% of incorporated amounts of 9cis-11 trans and 10trans-12 cis, respectively) than that of oleate (P<0.01). Total oxidation of oleate and CLA isomers into [¹⁴CO₂] was low (2 to 7% of total oxidized FA) compared to the partial oxidation (93 to 98%) leading to the production of [¹⁴C] acid-soluble products. CLA isoemrs escaping from catabolism were both highly desaturated (26.7 and 26.8%) into conjugated 18∶3. Oleate and CLA isomers were mainly esterified into neutral lipids (30%). They were slowly secreted as parts of VLDL particles (<0.4% of FA incorporated into cells), the extent of secretion of oleate and of 10trans-12 cis being 2.2-fold higher than that of 9cis-11 trans (P<0.02). In conclusion, this study clearly showed that both CLA isomers were highly catabolized by hepatocytes, reducing their availability for peripheral tissues. Moreover, more than 25% of CLA escaping from catabolism was converted into conjugated 18∶3, the biological properties of which remain to be elucidated.     

巴豆酸乙烯酯的提取及聚合应用

巴豆酸乙烯酯存在于醋酸乙烯酯生产的工业废液中,在一定条件下聚合会形成环状结构。用于改性以聚醋酸乙烯酯为基础的乳胶漆无须引发剂和加热,只是简单混和即可使耐洗刷次数增加几倍,还可与其它乙烯基酯、氯乙烯、苯乙烯、马来酸酐等多种单体交联共聚。     

基于ENVI软件的遥感影像内插方法偏差改正

ENVI是由遥感领域的科学家采用交互式数据语言IDL(Interactive Data Language)开发的一套功能强大的遥感图像处理软件,其能够快速、便捷、准确地从遥感影像中提取所需的信息。为了对影像进行更好的分析和处理,ENVI提供了一套基础的影像内插方法用于对影像进行插值处理。然而,由于理论上的缺陷,其采用的插值方法存在一定的偏差,从而导致后续的影像处理工作中引入了人为的误差影响。因此基于ENVI软件所用的影像内插方法,从理论入手指出其不足之处并对其模型进行改正。通过实验证明,改正后的内插方法能够获得更为准确的插值影像,从而为下一步的处理提供更为准确的数据结果。     

独立光柴混合微电网新的负荷频率控制研究

针对光柴混合发电的孤岛微电网,提出基于滑模控制和超级电容调节的频率控制方法。首先,建立光伏系统、超级电容和柴油发电机系统的数学模型;其次,设计滑模控制器来调节柴油机发电机的有功输出功率,减小由于光伏输出功率波动和微网中不断变化的负荷而产生的频率偏差;最后增加超级电容储能设备控制微网的频率偏差。仿真结果表明,与传统的柴油发电机速度控制策略相比,提出的方法不仅实现了光伏系统的最大输出功率控制,而且有效的减少了孤岛微网的频率偏差。     

能量均衡的最小2-连通2-支配集的分布式算法

在无线传感器网络中,一般通过构造连通支配集形成虚拟骨干网来分层路由。现有算法通常只考虑如何获得规模较小的支配集,忽略网络自身的不稳定性,使得节点失效或链路失败经常发生。针对连通支配集的容错能力,结合节点度与能量因素,提出一种能量均衡的最小2-连通2-支配集的分布式算法（DA-EBM）。 Omnet仿真实验表明, DA-EBM算法构造的容错连通支配集能有效均衡能量消耗,延长网络生命周期。     

数字化微格教学系统在师范生培养过程中的应用研究

师范生的培养效果如何关乎到未来教师的教学能力,本文通过对当前我国师范生培养现状的分析,探讨如何应用数字化微格教学系统培养师范生的教学能力。     

Preparation Polyelectrolyte Complexes of Chitosan-Polyacrylic Acid-Modified Iron Sand Leachate for Proton Exchange Membranes

ABSTRACT

Polyelectrolyte complex (PEC) of chitosan (Chi) and poly (acrylic acid) (PAA)-modified iron sand leachate were prepared and considered for applicability as a proton exchange membrane in fuel cells. Chi-PAA-hematite blended in different weight ratios and the resulting membranes were treated to enable the formation of the polyelectrolyte. The membranes of Chi-PAA polyblend were treated using iron sand leachate and reveal high ion exchange capacity (IEC), proton conductivity, water uptake, and good mechanical stability. The result of research indicated that the membrane with 40 wt% of Chi and 60 wt% of PAA blend which its conductivity of 6.10 × 10^?2 S cm^?1 was potentially for a proton exchange membrane in fuel cell applications.     

Obesity: Prevalence,Theories, Medical Consequences,Management, and Research Directions

Obesity and its associated disorders are a growing epidemic across the world. Many genetic, physiological, and behavioral factors play a role in the etiology of obesity. Diet and exercise are known to play a valuable role in the treatment and prevention of obesity and associated disorders such as hypertension, heart disease, and diabetes. Therefore, the purpose of this review is to examine the prevalence, etiology, consequences, and treatment of obesity.     

遗传算法理论及其应用研究进展

首先阐述遗传算法的原理和求解问题的一般过程;然后讨论了近年来从遗传算子、控制参数等方面对遗传算法的改进,并对遗传算法在计算机科学与人工智能、自动控制以及组合优化等领域的应用进行陈述;最后评述了遗传算法未来的研究方向和主要研究内容。