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Hwee Yoong Felicia Gok Shahram Emami Jianhneg Shen Martin J. T. Reaney 《Journal of the American Oil Chemists' Society》2013,90(2):299-305
Biodiesel, fatty acid methyl ester (FAME), was produced by transesterification of canola oil with methanol in the presence of a series of alkoxide/hydroxide base catalysts produced from glycerol, 1,2-propanediol, 1,3-propanediol, xylitol, or sorbitol produced by dehydration reaction of sodium hydroxide in the presence of polyols. Transesterification reactions proceeded efficiently in the presence of sodium alkoxide catalysts prepared at three different mole ratios of sodium hydroxide to glycerol (1:1, 2:1, and 3:1). The production of methyl ester during the course of the reaction was determined repeatedly and the reaction progress was compared with that achieved in a reaction catalyzed by freshly prepared anhydrous sodium methoxide as a standard catalyst. Sodium alkoxide/hydroxide catalysts activity during the first 2 min of the reaction was in the order of: sorbitol < xylitol < sodium methoxide < 1,2-propanediol < 1,3-propanediol < glycerol regardless of the mole ratio of sodium hydroxide to glycerol. All catalysts showed a higher methyl ester accumulation at higher ratios of sodium hydroxide to polyol and had the following order 1:1 < 2:1 < 3:1 (sodium hydroxide:glycerol). Several of these catalysts were as powerful as sodium methoxide in catalyzing the transesterification reaction at the same mole concentration. All alkoxide/hydroxide catalysts resulted in a high FAME accumulation (>95 wt%) in a single transesterification batch reaction. 相似文献
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Rodolfo Villarreal-Calderon Maricela Franco-Lira Angélica González-Maciel Rafael Reynoso-Robles Lou Harritt Beatriz Pérez-Guillé Lara Ferreira-Azevedo Dan Drecktrah Hongtu Zhu Qiang Sun Ricardo Torres-Jardón Mariana Aragón-Flores Ana Calderón-Garcidue?as Philippe Diaz Lilian Calderón-Garcidue?as 《International journal of molecular sciences》2013,14(12):23471-23491
Mexico City Metropolitan Area children and young adults exposed to high concentrations of air pollutants including fine and ultrafine particulate matter (PM) vs. clean air controls, exhibit myocardial inflammation and inflammasome activation with a differential right and left ventricular expression of key inflammatory genes and inflammasomes. We investigated the mRNA expression levels of the prion protein gene PRNP, which plays an important role in the protection against oxidative stress and metal toxicity, and the glucose regulated protein 78, a key protein in endoplasmic reticulum (ER) stress signaling, in ventricular autopsy samples from 30 children and young adults age 19.97 ± 6.8 years with a lifetime of low (n:4) vs. high (n:26) air pollution exposures. Light microscopy and transmission electron microscopy studies were carried out in human ventricles, and electron microscopy studies were also done in 5 young, highly exposed Mexico City dogs. There was significant left ventricular PRNP and bi-ventricular GRP78 mRNA up-regulation in Mexico City young urbanites vs. controls. PRNP up-regulation in the left ventricle was significantly different from the right, p < 0.0001, and there was a strong left ventricular PRNP and GRP78 correlation (p = 0.0005). Marked abnormalities in capillary endothelial cells, numerous nanosized particles in myocardial ER and in abnormal mitochondria characterized the highly exposed ventricles. Early and sustained cardiac ER stress could result in detrimental irreversible consequences in urban children, and while highly complex systems maintain myocardial homeostasis, failure to compensate for chronic myocardial inflammation, oxidative and ER stress, and particles damaging myocardial organelles may prime the development of pathophysiological cardiovascular states in young urbanites. Nanosized PM could play a key cardiac myocyte toxicity role. 相似文献
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本文研究了含铅高温PTC半导体陶瓷材料的性能和工艺特点。采用快速烧结法获得了性能优良的(Ba,Pb)TiO_3系半导体材料。 相似文献
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分析8279芯片的显示接口及十六段和八段LED显示驱动电路的特点,提出了十六段和八段LED混合显示驱动的方法,并介绍了一种经济、实用的显示驱动电路。 相似文献
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中间相沥青基碳纤维具备高模量、高导热性等特性,在航天、电子等领域具备广阔的应用前景.山东瑞城实现了中间相沥青基碳纤维的产业化生产,本文对其所生产的中间相沥青基碳纤维的结构和性能进行了表征研究.研究结果表明,1.5K连续纤维的平均直径为11μm;强度为2400 MPa;模量为811 GPa;导热率达到600 W/(m·k... 相似文献