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101.
Nowadays, more than 85% of the energy is generated by fossil fuels. The excessive utilization of finite fossil fuels has resulted in the crises of energy shortage and global warming caused by greenhouse gas emissions. Researchers have conceived several means for trying to solve these problems, among which the sunlight-driven CO2 reduction is viewed as a sustainable process that utilizes CO2 as the raw material to produce chemical fuels, including CO, formate, and CH4; this method not only realizes the conversion and storage of intermittent solar energy, but also decreases the CO2 concentration in the atmosphere and alleviates global warming. However, photochemical CO2 reduction usually undergoes a sluggish process due to the inertness of CO2. Moreover, the selectivity of the CO2 reduction reaction is also challenged by the hydrogen evolution reaction, which exhibits faster reaction kinetics. In this context, the rational design and synthesis of efficient and selective catalysts for photochemical CO2 reduction are major challenges. 相似文献
102.
Tong J Nakajima M Nabetani H Kikuchi Y Maruta Y 《Journal of colloid and interface science》2001,237(2):239-248
From the point of view of practical application of the microchannel (MC) emulsification technique, which can be used to produce super-monodispersed microspheres (MS), we fabricated a stainless steel MC and investigated the production and characterization of oil-in-water (O/W) MS using a stainless steel MC instead of a silicon MC plate. We discovered that a stainless steel MC could not be fabricated precisely at a 1-&mgr;m scale; because of its multicrystal property, it can only be processed mechanically on a 10-&mgr;m scale. O/W-MS ranging from 20 to 210 &mgr;m in average diameter were produced using a stainless steel MC with 10 to 80 &mgr;m in equivalent diameter. The MS produced were monodispersed with a coefficient of variation lower than 3% for each individual channel. This value is smaller than that of normal emulsions obtained by the conventional emulsification techniques by 1 order of magnitude. The average diameter of the MS produced at breakthrough pressure was about 2.6 times the stainless steel MC equivalent diameter. The operation pressure affects the MS formation, causing a size-stable zone, size-expanding zone, and outflow zone observed. Larger stainless steel MC demonstrated difficulties in stably producing monodispersed O/W-MS. The breakthrough pressure was approximately inversely proportional to the MC equivalent diameter. Copyright 2001 Academic Press. 相似文献
103.
Xiaolin Hou Xiaowei Li Shuangyang Ding Jihong He Haiyang Jiang Jianzhong Shen 《Chromatographia》2006,63(11-12):543-550
A rapid, simple and sensitive LC-MS-MS method was developed to simultaneously measure residues of avermectin, ivermectin, doramectin, and eprinomectin in bovine liver and muscle. The extracted samples were cleaned by an immunoaffinity column which was prepared by coupling anti-avermectin polyclonal antibodies with CNBr-activated Sepharose 4B. The residues eluted from the column were analyzed by high-performance liquid chromatography with tandem mass spectrometry. Recoveries fortified at levels 5?50 ng g?1 ranged from 62.93 to 84.03%, with relative standard deviations from 6.02 to 17.39% for all four compounds in liver tissue. The limits of quantification were 5 ng g?1, and limits of detection were 2.5 ng g?1 in liver for the four drugs. The procedure was also applied to bovine muscle, giving similar results. 相似文献
104.
105.
傅里叶变换用于铁和锌的同时光度测定 总被引:7,自引:0,他引:7
研究了傅里叶变换技术用于铁锌二组分的同时分光光度测定,采用傅里叶变换对吸光度数据进行预处理,再结合目标转换因子分析或偏最小二乘分析,结果较普通的目标转换因子分析或偏最小二乘法有显著改善。以傅里叶变换-偏最小二乘法就用于实际铝合金样品中铁和锌的同时测定,结果令人满意。 相似文献
106.
107.
Abstract C-1-thioacetalization of L-idofuranurono-6,3-lactone followed by regioselective p-methoxybenzylidenation at C-2 and C-4 gave the hydroxylactones 4 and 19, which were protected at C-5 with TBDMS. Lactone ring opening with methylamine followed by regioselective reductive cleavage of the 1,3-dioxane furnished acceptors 9 and 24. Intermolecular ethyl and phenyl thio group transfers were observed during the attempted preparation of disaccharide 35 through coupling reactions of either 9 or 24 with trichloroacetimidate donor 33, leading to the formation of thioglycoside of donor 33 and the thioglycoside of acceptors 9 or 24 in the furanose form. This intermolecular aglycon transfer was investigated under various glycosylation conditions. Finally, the free 4-hydroxyl groups in acceptors 9 and 24 were acetylated. Desilylation at C-5 followed by ring closure with mercuric salts afforded, in both cases, the IdopA donor and/or acceptor precursor 16. 相似文献
108.
Junya Takashima Kazumasa Sugiyama Tokuhei Tagai Osamu Terasaki Jihong Yu 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):m333-m334
The title compound, (C4H7N2)2[AlP2O7(OH)], is a one‐dimensional extended‐chain aluminophosphate prepared by a solvothermal synthesis from an alcohol system. The infinite [AlP2O7(OH)]2− chains composed of AlO4, PO2(=O)2 and PO2(=O)(OH) tetrahedra are linked via hydrogen bonds to the 2‐methylimidazolium cations. 相似文献
109.