排序方式: 共有132条查询结果,搜索用时 0 毫秒
51.
52.
用密度泛函理论(DFT)的Bexke3lyp方法,对铀原子采用相对论有效原子实势及(6s5p2d4f)/[3s3p2d2f]收缩价基集合,碳、氧原子采用6-311G价基集合,应用Gaussian98程序对一氧化碳气体与铀表面相互作用的可能分子结构U-C-O、U-O-C、C-U-O(角形Cs和线形C∞v)等,进行abinitio优化计算.得到了十二种三重态或五重态的相对稳定结构的电子状态、几何构形、能量、谐振频率、力学性质和电性质等,并给出了角形和线形结构的正则振动分析图.结果表明,Cs构型的能量都比较低,尤其以U-C-O角形结构(3A″)为最低;通过对各成键原子间重叠布居数及键能分析知,U与CO的结合力较弱,O原子比C原子与U原子的结合力稍强. 相似文献
53.
54.
55.
MAO Bing-Wei MU Ji-Qian ZHUO Xiang-Dong FENG Zu-De YAN En-Rou PAN Guo-Bin XIE Zhao-Xiong REN BinState Key Laboratory for Physical Chemistry of the Solid Surface Chemistry Department Xiamen University Xiamen Fujian China 《中国化学》1995,13(2):105-111
The development of the instrumentation of a scanning electrochemical microscopy (SECM) is presented. The core of the SECM sensing system is constructed based on piezobimorph scanners, a mechanical micropositioner of multi-dimensional adjustment and ultramicroelectrodes. The control of the electrochemical cell and the SECM system is realized by a battery powered bipoteniostat and analog control circuits respectively with the control of a microcomputer work station. The demonstrations of SECM experiments are given on both a standard IDA sample and a silver electrode. Discussions on the resolution and quality of SECM image are made. 相似文献
56.
Regioselective Synthesis and Base Catalyzed Transacylation of Substituted 1H—Pyrazole—4—carboxamides
New type of substituted 1H-pyrazole-4-carboxamides were obtained by regioselective synthesis under the catalysis of different based.The stuctures of the title compounds were confirmed by elemental analysis,^1H NMR,IR,MS and X-ray crystallography.Compounds 1 were transcaylated into their corresponding.Compounds 1 were transacylated into their corresponding amides 3 in the prsence of sodium hydride.Preliminary bioassays indicated that some compounds showed fungicidal activities against Rhizoctonia solani and Sclerotinia sclerotiorum. 相似文献
57.
建立了一种快速、灵敏地检测痕量芳香醇的新方法。对于苯甲醇、β-苯乙醇、二苯甲醇、水杨醇及苯乙二醇五种芳香醇与对酞内酰胺苯甲酰氯衍生反应、色谱分离及定量分析条件作了研究。测定了五种芳香醇衍生物的摩尔吸光系数。检测限为1.3~4.7 pmol。 相似文献
58.
Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O2 pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al2O3catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 molH2 mol 1 Ni. A direct relationship between Ni metal surface area and hydrogen yields was established. 相似文献
59.
RING Peter 《中国科学:物理学 力学 天文学(英文版)》2011,(2)
The g factors and spectroscopic quadrupole moments of low-lying excited states 2+1,…,81+ in 24Mg are studied in a covariant density functional theory.The wave functions are constructed by configuration mixing of axially deformed mean-field states projected on good angular momentum.The mean-field states are obtained from the constraint relativistic point-coupling model plus BCS calculations using the PC-F1 parametrization for the particle-hole channel and a density-independent delta-force for the particle-pa... 相似文献
60.
硅藻土表面羟基的漫反射红外光谱(DRIFT)研究 总被引:3,自引:0,他引:3
运用傅里叶变换漫反射红外光谱(DRIFT)及氘化技术,研究了硅藻土的表面羟基结构及其在热处理中的变化。 相似文献