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de Farias RF de Souza JM de Melo JV Airoldi C 《Journal of colloid and interface science》1999,212(1):123-129
The effects exhibited by adsorbed conducting polyaniline on the redox process on a molybdenum oxide surface were studied. Thermogravimetric results indicate a 4% polyaniline deposition. Cyclic voltammograms of the adsorbed polymer on MoO3 show that polyaniline exerts remarkable effects on the molybdenum blue oxidation-reduction process, with oxidation and reduction potentials of 0.33 and 0.18 V, respectively. This effect strongly enhances the electrode response, and can be used as an important tool in qualitative and/or quantitative determinations of molybdenum in solution as well as in any substrate. Copyright 1999 Academic Press. 相似文献
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Vara Prasad JV 《Organic letters》2000,2(8):1069-1072
[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity. 相似文献
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A Continuous-Wave Ho:YA103 Laser with Output 8.5 W Pumped by a 1.91μm Laser at Room Temperature 下载免费PDF全文
A cw high efficient Ho:YAI03 laser pumped by 1.91 μm diode-pumped Tm:YLF laser at room temperature is realized. The maximum output power reaches 8.5 W when the incident pump power is 15.6 W. The slope efficiency is 63.7%, and the Tm:YLF to Ho:YAP optical conversion efficiency is 54.5%. The laser wavelength is 2118.3nm when the transmission of output coupler is 30%. The beam quality factor is M2 -1.39 measured by the traveling knife-edge method. 相似文献
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Adachi M Zhang Y Leimkuhler C Sun B LaTour JV Kahne DE 《Journal of the American Chemical Society》2006,128(43):14012-14013
Moenomycin A is the only known natural product that inhibits peptidoglycan biosynthesis by binding the bacterial transglycosylases. We describe a degradation/reconstruction route to manipulate the reducing end of moenomycin A. A comparison of the biological and enzyme inhibitory activity of moenomycin A and an analogue containing a nerol lipid in place of the natural C25 lipid chain provides insight into the role of the moenocinol unit. Our results show that a lipid chain having ten carbons in moenocinol is sufficient for enzyme inhibition, but a longer chain is required for biological acitivity, apparently because the molecule must partition into biological membranes to reach its target in bacterial cells. 相似文献
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针对析氢腐蚀实验中出现的异常现象,依据金属电化学腐蚀原理,通过实验探究确定影响析氢腐蚀实验的主要因素——氧气。在此基础之上,设计出演示吸氧腐蚀、析氢腐蚀的套管实验以及析氢腐蚀的微型化实验方案。 相似文献
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de Farias RF de Souza JM de Melo JV Airoldi C 《Journal of colloid and interface science》2000,227(1):147-151
Polyaniline deposited on As(2)O(3) surface resulted in a new material, which was characterized by infrared spectoscopy, thermogravimetry, differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and cyclic voltammetry. The mass percentage of polymer deposited on oxide surface is approximately 13%. The scanning electron microscopy images as well as the X-ray diffraction patterns provided conclusive evidence that the oxide surface is coated by the polymer. The cyclic voltammograms of the polyaniline adsorbed on As(2)O(3) surface showed that the adsorbate exerts remarkable effects on redox processes on this oxide. The pure oxide exhibited two oxidation/reduction peaks at 0.25/-0.06 and 0.47/-0.25 V attributed tentatively to the processes As(2)O(3)(s)+6H(+)+6e(-)=2As(s)+3H(2)O and As(s)+3H(+)+3e(-)=AsH(3)(g), respectively. The polyaniline-coated sample exhibited a better-defined voltammogram in which the first oxidation peak of the oxide had its intensity increased about four times. Copyright 2000 Academic Press. 相似文献
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针对铜锌原电池中锌电极冒气泡的“异常”现象,通过分析不同类型原电池的工作原理,认为即使使用纯度极高的锌也会产生气泡,并给出其缘由。对在教学中如何处理这一棘手的难题,提出个人见解。同时,建议中学化学教材将“锌片上产生气泡”的现象明确地描述出来。 相似文献
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Hybrid glycopeptide antibiotics. 总被引:1,自引:0,他引:1
B Sun Z Chen U S Eggert S J Shaw J V LaTour D Kahne 《Journal of the American Chemical Society》2001,123(50):12722-12723