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951.
足球分子及有关碳笼的电子结构 总被引:1,自引:0,他引:1
本文评述了激光气化产生的碳原子簇的电子结构和活性。足球分子具有球面芳香性。我们用INDO/2和INDO/CI系列方法。研究了足球分子及其异构体的电子结构和UV谱。足球分子的计算结果是只有一条低频带(366.4nm),与实验结果(386.0nm)符合得很好。 相似文献
952.
Phase separation in the formation of hollow particles by suspension polymerization for divinylbenzene/toluene droplets dissolving polystyrene 总被引:1,自引:0,他引:1
Phase-separation behavior within polymerizing divinylbenzene/toluene droplet dissolving polystyrenes (PS) was investigated to clarify the formation mechanism of the hollow polymer particles by suspension polymerization. No hollow particles were obtained at a low content of low-molecular-weight PS where phase separation occurred at high conversion. On the other hand, hollow particles were obtained at a high content of high-molecular-weight PS where phase separation occurred at low conversion. The phase separation in an early stage of the polymerization, which was promoted by the presence of PS and cross-links of polydivinylbenzene, was a key factor for the formation of the hollow structure. 相似文献
953.
Xianfeng?You Feng?Chen Jinlong?ZhangEmail author 《Journal of Sol-Gel Science and Technology》2005,34(2):181-187
TiO2 powders were prepared by sol–gel template method and calcined under different conditions. XRD, BET and TEM were used to characterize the TiO2 powders obtained. The photocatalytic activity of TiO2 was investigated by the degradation of methyl orange. It was found that TiO2 powder has the highest photocatalytic activity at a calcination temperature of 673 K. The effects of physical properties such as surface area, crystallinity and crystal phase on the photocatalytic activity of TiO2 were discussed. 相似文献
954.
本非水电池体系由Li负极、多孔石墨电极和电解质溶液组成;电解质溶液由无机溶剂POCl_3(或有机溶剂硝基苯)和溶解在该溶剂中的活性物质(KIBr_2)及支持电解质构成。该电池体系的开路电压为8.50伏左右,放电性能良好,可望在实际中得到应用。此外,对电池体系的反应机理也作了初步的探讨。 相似文献
955.
ZrO2对合成二甲醚双功能催化剂表面结构及催化性能的影响 总被引:5,自引:0,他引:5
采用共沉淀沉积法制备了Cu基双功能催化剂,并进行了合成气一步法制取二甲醚实验.XRD、XPS以及BET表征结果表明,催化剂中ZrO2以无定形状态存在,且随着其含量的增加,Zr^4 逐渐溶进CuO晶格,两者之间的电子交换使得Cu^2 在活化过程中很难被彻底还原为Cu^0,而是以Cu^0/Cu^ 的形式共存.活性评价结果表明,Cu^ 离子表现出优异的CO转化率和DME选择性.同时,ZrO2的存在能有效调节催化剂表面的Cu/Zn摩尔比以及促进Cu元素在表面的富集,从而改善催化剂性能. 相似文献
956.
G. Z. Kaziev A. A. Dutov S. I. Quinones A. de Ita S. N. Sychkin 《Russian Journal of General Chemistry》2005,75(1):18-20
Indium dodecatungstosilicate of the composition [In(OH)⋅5H2O]2 [SiW12O40]⋅H2O is synthesized and studied by means of IR spectroscopy, thermogravimetry, and X-ray phase analysis. The crystals of this compound are triclinic, space group P1, a 13.079(3), b 13.795(3), c 13.967(3) Å, α 90.08(3)°, β 103.76(3)°, ψ107.76(3)°, Z 2, and πcalc 4.900 g cm−3.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 21–23.Original Russian Text Copyright © 2005 by Kaziev, Dutov, Quinones, Ita, Sychkin. 相似文献
957.
Protein tyrosine phosphatase 1B (PTP1B) functions by removing the phosphoryl group from tyrosinephosphorylated proteins in
insulin signaling and metabolism. The regeneration of the active site involves a sulphenylamide intermediate derived from
the intrastrand cross-linking between the catalytic serine and the neighboring backbone nitrogen. Two mechanisms have been
proposed for the formation of the sulphenylamide intermediate and the subsequent reactivation of the catalytic site. In the
current work, the proposed mechanisms have been investigated by the use of density functional theory calculations. Our results
suggest that these two mechanisms have similar overall energy barriers and that the preferred route will be determined by
the availability of hydrogen peroxide or other oxidizing reagents. 相似文献
958.
Summary. A highly efficient, selective, fast, and cheap protocol is developed for oxidation of aromatic amines and alcohols utilizing
34% hydrogen peroxide in water catalyzed by some W- and Mo-based heteropolyoxometalates. Findings showed that dodecatungstophosphoric
acid, H3PW12O40, was the most efficient catalyst in the examined oxidation reactions. This methodology may prove to be a valuable alternative
for eco-friendly green oxidation. Inherent simplicity, easy work up, and using regenerable catalysts were other key aspects
of this oxidation protocol. 相似文献
959.
流动注射化学发光法测定甲氨蝶呤 总被引:8,自引:0,他引:8
研究了甲醛增强高锰酸钾与甲氨蝶呤的化学发光反应,由此建立了一种测定甲氨蝶呤的流动性注射化学发光分析法,方法的检出限为3.4×10^-9g/mL,相对标准偏差为1.1%(2.0×10^-6g/mL甲氨蝶呤,n=11)线性范围为1.0×10^-8~1.0×10^-5g/mL。该法已用于甲氨蝶呤针剂及片剂中甲氨蝶呤含量的测定。 相似文献
960.
Three new one-dimensional coordination polymers [Zn8S(SC6H5)14.C12H10N2](1), [Zn7CoS(SC6H5)14.C13H14N2](2) and [Zn8S(SC6H5)14.C13H14N2](3) have been prepared containing penta-supertetrahedral clusters and linear crosslinking dipyridyl ligands; the two complexes show optical transitions with band gaps of approximately 3.44 eV (1) and approximately 3.54 eV (2). 相似文献