Phase behavior of the base-catalyzed transesterification of soybean oil

Biodiesel is made by the transesterification of vegetable oils to form alkyl FA esters. High levels of conversion (>99%) are required to lower the total concentration of free and chemically bound glycerol to that allowed by the ASTM standard (0.240 wt%) for biodiesel. A polar dye was used to visualize the phase behaviors in methanolysis, ethanolysis, and butanolysis. The dye was more strongly colored in more polar phases. Methanolysis and ethanolysis reactions commenced as two phases (alcohol and oil), then formed emulsions, and ended as two phases as glycerol-rich phases separated. Ethanolysis was more easily initiated by mixing than was methanolysis. Ethanolysis also exhibited a much longer emulsion period and slower glycerol separation. The glycerol-rich phase was smaller in volume in ethanolysis than in methanolysis. Butanolysis remained one phase throughout, and no polar phase existed at any time. The results are consistent with the known phase compositions in these reactions. The concentrations of MG, DG, and TG in the products with time in stirred reactions were consistent with the observed phase behavior in the dye experiments.     

Synergistic Catalysis of Carbon Dioxide Hydrogenation into Methanol by Yttria-Doped Ceria/γ-Alumina-Supported Copper Oxide Catalysts: Effect of Support and Dopant

Methanol synthesis from carbon dioxide hydrogenation was studied over ceria/-alumina- and yttria-doped ceria (YDC)/-alumina-supported copper oxide catalysts to seek insight into the catalysis at metal–support interfaces. It was found that, in comparison with Cu/-Al₂O₃, the Cu/CeO₂/-Al₂O₃ and Cu/YDC/-Al₂O₃ catalysts exhibited substantial enhancement in activity and selectivity toward methanol formation. The extent of enhancement was augmented by increased ceria loading on -alumina and with increased yttria doping into ceria. The enhancement is inferred to result from the synergistic effect between copper oxide and surface oxygen vacancies of ceria.     

Antioxidant activity in leaves of some mediterranean plants

Hexane and methanol leaf extracts of sixteen Mediterranean plant species were obtained by percolation. Higher yields were observed for methanol (16.4–47.8%) than for hexane extracts (1.3–13%). Antioxidant activity of these extracts was determined by a rapid spectrophotometric method involving the combined oxidation of beta-carotene and linoleic acid. Leaf extracts were thus characterized by an Antioxidant Activity Coefficient (AAC) ranging from 0 to 1000. Hexane extracts gave much higher AAC values than the corresponding methanol extracts. In both cases, myrtle (Myrtus communis) showed the best antioxidant effectiveness.     

甲醇工业发展方向及应用分析

介绍了甲醇的几种重要的下游产品,如甲醛、甲酸甲酯、甲胺等,提出应大力生产和发展甲醇下游产品,并进一步拓宽甲醇的应用领域,加快甲醇应用新技术的开发工作。     

互联网应用发展和用户行为解析

互联网在我国迅猛发展,其应用不断创新发展。本文从搜索引擎、社交网站、电子商务、网络视频、网络游戏、移动互联网6个方面对互联网应用发展现状以及各种用户的行为习惯进行研究．最后分析了各种互联网应用的发展趋势。     

模糊逻辑在模拟演练系统智能体设计中的应用

根据模拟演练系统对智能体智能程度的要求为模拟演练系统添加模糊推理机,以增加演练系统的逼真程度及适应性. 本文以模糊逻辑理论为基础,以模拟演练系统为背景,对一个具体的应用实例进行数学建模,阐述了如何运用模糊逻辑来解决问题,并设计了模糊逻辑模块,通过应用实例演示验证了设计的可行性.     

文献搜索引擎中特征项及权重的应用

针对目前用户在使用搜索引擎过程中,检索结果冗余、效率低下等问题,本文在对文献垂直搜索系统中Lucene.Net的索引算法研究基础上,结合用户实际专业检索需求,改变其算法中的激励因子,实验结果证明该方法确能提高搜索结果的相关度.     

非晶有机锆聚合物的制备及光催化CO2合成甲醇

采用溶剂热法在增透的多孔玻璃表面制备负载非晶态有机锆聚合物。通过SEM，XRD，BET，FTIR，UV-Vis，ICP，有机元素分析，荧光光谱（PL）及紫外光电子能谱（UPS ）等手段对催化剂进行了测试分析。非晶态有机锆聚合物（2.64 eV）具有比NH2-UiO-66(Zr)（2.74 eV）更窄的禁带宽度，更稳定的光生电子。在光催化反应器中放入2片负载非晶态有机锆的玻璃（总面积50.4 cm2），在300 W的氙灯照射下催化还原CO2合成甲醇，反应4 h后甲醇的产量为443.0 μmol，转换频率（TOF）为8.9 h-1。当0.1 g NH2-UiO-66(Zr)为催化剂时，甲醇的产量为244.3 μmol，TOF仅为0.17 h-1。非晶有机锆聚合物的光催化性能明显优于NH2-UiO-66(Zr)粉末，且循环稳定性良好。     

一种跨平台实时控制系统设备驱动的设计与实现

针对实时控制系统接入各种现场设备并与之通讯的问题,提出并设计了一种跨平台实时控制系统的现场设备驱动。首先概述了设计的基本原理,然后详细阐述了驱动函数,驱动模块,驱动引擎等各模块的设计及在多操作系统平台的实现。最后以实际的使用示例说明设备驱动的使用方法。     

新型车用清洁燃料——甲醇汽油

介绍了几种代用清洁燃料,着重介绍了甲醇燃料的特点、发展历史和使用现状,并且从其对环境的影响、着火爆炸的安全性以及毒性等方面论述了甲醇燃料的使用安全性能。