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131.
Shen YF Fang CJ Peng ZH Li DC Zhou YH 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(1-3):132-139
The molecular structure and binding, as well as infrared and electronic spectroscopic properties for the title complex Cu(mnt)(dmbpy)(mnt(2-)=maleonitriledithiolate, dmbpy=4,4'-dimethyl-2,2'-bipyridine) were studied in this paper. With semi-empirical PM3 and non-empirical DFT (B3LYP/6-311G*) methods, the molecular geometry of the complex was optimized and corresponding vibrational spectra in the gaseous state were obtained. The calculated results derived from DFT were more reasonable than those from PM3. The point group of Cu(mnt)(dmbpy) in isolated gaseous state was C(2), in which Cu(II) adopted a distorted tetrahedral geometry and the dihedral angle between the N(2)Cu and S(2)Cu planes was about 29.814 degrees. And a complete assignment to the IR spectra of such a complicated molecule was exhibited. With ZINDO/S method an electronic spectrum was calculated. The results showed that the calculated values generally agreed with the observed ones. And a detailed explain was made on its electronic spectra. 相似文献
132.
贵金属同时浮选分离富集行为的研究及ICP-AES的测定 总被引:3,自引:0,他引:3
本文通过对贵金属-碘化钾-孔雀绿显色体系的浮选行为研究,建立了一种同时浮选富集分离铂、钯、铑、铱、金的新方法。实验结果表明,在0.36mol/LHCl0.1mol/LKI和2.4×10 ̄(-4)mol/LMG的溶液中,加入环已烷振荡1min,铂、钯、铑、铱、金可被定量浮选,继而用ICP-AES测定。对含量为5~150μg的贵金属,浮选回收率分别为铂88.6%~95.7%,钯92.3%~99.5%,铑93.7%~101%,铱92%~98.5%,金86.4%~94%。方法应用于铜镍矿、铂网废料等物料中上述贵金属元素的测定,结果满意。 相似文献
133.
134.
L. J. Ning Y. P. Wu L. Z. Wang S. B. Fang R. Holze 《Journal of Solid State Electrochemistry》2005,9(7):520-523
Three kinds of silicon-containing disordered carbons have been prepared by pyrolysis of polysiloxanes with different amounts of phenyl side groups. X-ray powder diffraction, X-ray photoelectron spectroscopy and electrochemical capacity measurements were performed to study their behaviors. Graphite crystallites, micropores, and silicon species affect their electrochemical performances. All of them present high reversible capacities, >372 mAh/g. Since the graphite crystallites are very small, they contribute very little to reversible capacity. The number of micropores produced by gas emission during the heat-treatment process decides whether they exhibit reversible capacity. Si mainly exists in the form C–Si–O and influences the irreversible capacity. There is no evident capacity fading in the first ten cycles, indicating promising properties for these disordered carbons. 相似文献
135.
QSAR models using a large diverse set of estrogens 总被引:12,自引:0,他引:12
Shi LM Fang H Tong W Wu J Perkins R Blair RM Branham WS Dial SL Moland CL Sheehan DM 《Journal of chemical information and computer sciences》2001,41(1):186-195
Endocrine disruptors (EDs) have a variety of adverse effects in humans and animals. About 58,000 chemicals, most having little safety data, must be tested in a group of tiered assays. As assays will take years, it is important to develop rapid methods to help in priority setting. For application to large data sets, we have developed an integrated system that contains sequential four phases to predict the ability of chemicals to bind to the estrogen receptor (ER), a prevalent mechanism for estrogenic EDs. Here we report the results of evaluating two types of QSAR models for inclusion in phase III to quantitatively predict chemical binding to the ER. Our data set for the relative binding affinities (RBAs) to the ER consists of 130 chemicals covering a wide range of structural diversity and a 6 orders of magnitude spread of RBAs. CoMFA and HQSAR models were constructed and compared for performance. The CoMFA model had a r2 = 0.91 and a q2LOO = 0.66. HQSAR showed reduced performance compared to CoMFA with r2 = 0.76 and q2LOO = 0.59. A number of parameters were examined to improve the CoMFA model. Of these, a phenol indicator increased the q2LOO to 0.71. When up to 50% of the chemicals were left out in the leave-N-out cross-validation, the q2 remained significant. Finally, the models were tested by using two test sets; the q2pred for these were 0.71 and 0.62, a significant result which demonstrates the utility of the CoMFA model for predicting the RBAs of chemicals not included in the training set. If used in conjunction with phases I and II, which reduced the size of the data set dramatically by eliminating most inactive chemicals, the current CoMFA model (phase III) can be used to predict the RBA of chemicals with sufficient accuracy and to provide quantitative information for priority setting. 相似文献
136.
叙述了用θ-2θ型X射线衍射仪精确测定电解质溶液结构的新实验技术。设计制作了具有恒温功能的超厚液体样品池,并建立了样品池窗口强度的校正方法。优化了液体X射线衍射数据和结构参数精细化的计算机程序,获得了非常令人满意的实验结果。由θ-2θ型X射线衍射仪精确测定的径向分布函数与θ-θ型衍射仪自由散射比较,表明DRF分辨率有所提高。 相似文献
137.
Cu-Mg/Al复合氧化物催化碳颗粒物燃烧性能的研究 总被引:5,自引:0,他引:5
恒定二价与三价阳离子比为3(nM2+/nM3+=3),采用共沉淀法制备不同Cu含量的系列水滑石前驱物, 800 ℃焙烧4 h形成复合氧化物(CuO质量百分数分别为0%、5%、10%、15%、20%、30%、40%)用作柴油车排放碳颗粒物燃烧的催化剂,并采用XRD、BET、TG-DSC、FT-IR、TPR等表征手段研究了Cu、Mg含量对材料前驱物物化性能的影响及对其衍生复合氧化物催化碳颗粒物燃烧性能的影响.结果表明,Cu、Mg含量对材料的热稳定性、比表面和催化氧化活性有显著的影响. Mg有助于提高催化剂的热稳定性; Cu含量增加,催化剂比表面下降,但比表面不是影响催化剂活性的主要因素. CuO含量为15%时,催化剂具有最好的催化活性和稳定性,碳颗粒物的起燃温度(T10)和半转化温度(T50)分别为336 ℃和409 ℃.在CuO含量≤30%时可以形成结构完整的水滑石前驱物, CuO含量为40%时出现Cu(OH)2杂相; CuO含量< 20%时,经高温焙烧可得到均匀的复合氧化物, CuO含量≥20%时出现CuO偏析. TPR结果表明焙烧温度和复合氧化物的组成决定了材料的可还原性能. 相似文献
138.
139.
Wei SUN Dan Dan WANG Rui Fang GAO Jian SUN Kui JIAO 《中国化学快报》2006,17(12):1589-1591
In recent years the direct electron transfer of redox protein on electrode surface has attracted great attentions1. Different kind of modified electrode and various supporting films for immobilization of proteins had been proposed. But most of them are ba… 相似文献
140.