共查询到20条相似文献,搜索用时 9 毫秒
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元素周期系究竟终止于多少号元素的问题虽然在目前还没有解决,但是99号和100号元素的存在已经是没有问题的了。不过由于现在原子核研究工作的公开发表往往较慢,所以关于99号元素和100号元素的制法和性质,还没有详细的报导,目前仅仅知道有几篇文献记述这两种元素的发现。 C.Martin一文是一个报导消息的文章,并不是作者本人的工作报告。文中说:用碳核轰击94 相似文献
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采用密度泛函理论对噻吩分子在Ni(100),Cu(100)和Co(100)表面的吸附构型进行了GGA/PBE水平上的计算,通过比较吸附能及各结构参数,预测了各金属的脱硫活性.结果表明:噻吩在Ni表面发生了作用力较强的化学吸附,噻吩的S—C键有解离趋势;在Cu表面发生的是作用力较弱的物理吸附,噻吩分子构型并未发生较大变化;而噻吩在Co表面的吸附作用最强,噻吩的S—C键已经发生解离,和Co原子之间的距离已经达到甚至短于Co—S键的键长.这说明,金属的吸附脱硫活性为CoNiCu,与实验研究结果一致.此3种金属最稳定的分子吸附位均为hol45位. 相似文献
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离子束技术可以研究气态下离子和分子的相互作用,近来又用于研究离子和吸附分子的相互作用.通常气体分子在单晶表面上的吸附是定向的,故这种吸附不仅可以用来研究不同方向入射的离子束与吸附分子的相互作用,从中还可以获得有关吸附分子和表面基片原子之间的键合信息及入射离子在表面的中和效应信息.本文研究了10eV 的 N~ 离子束在清洁的和吸附了 CO 分子的 Ni(100)和 Cu(100)表面上的中和效应及其与 CO 的相互作用.选择该系统的原因是:(1)基态 N_2分子对清洁的 Ni,Cu 表面是不活泼的,在室温下无化学吸附;(2)关于 CO 在 Ni(100)和 Cu(100)表面上的化学吸附特性已有了充分的了解;(3)有关气相的 N~ -CO 系统的离子-分子相互作用亦已有了较为完整的研究.所以本文研究结果便于 相似文献
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K. Söllner 《Analytical and bioanalytical chemistry》1964,202(1):68-69
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Sb在Pt(100),Pt(110),Pt(111)及Pt(320)上不可逆吸附的电化学特性 总被引:3,自引:0,他引:3
研究了Sb在Pt(1 0 0 ) ,Pt(1 1 0 ) ,Pt(1 1 1 )和Pt(32 0 )单晶面上不可逆吸附的电化学特性 .发现当扫描电位的上限Eu≤ 0 .45V时 ,Sbad可以稳定地吸附在Pt(1 0 0 ) ,Pt(1 1 0 )和Pt(1 1 1 )表面 ,而Sbad在Pt(32 0 )表面稳定的电位较低 ,为Eu≤ 0 .40V .从饱和吸附Sb的铂单晶电极出发 ,通过改变电位扫描上限Eu 和电位扫描圈数可以获得不同Sb覆盖度 (θSb)的电极 .根据Sb和H在铂单晶电极表面共吸附的定量数据 ,对Sb在不同铂单晶面上饱和吸附的模型进行了初步探讨 . 相似文献
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We present a stereodynamics study of the dissociative chemisorption of vibrationally excited methane on the (100), (110), and (111) planes of a nickel single crystal surface. Using linearly polarized infrared excitation of the antisymmetric C-H stretch normal mode vibration (ν(3)), we aligned the angular momentum and C-H stretch amplitude of CH(4)(ν(3)) in the laboratory frame and measured the alignment dependence of state-resolved reactivity of CH(4) for the ν(3) = 1, J = 0-3 quantum states over a range of incident translational energies. For all three surfaces studied, in-plane alignment of the C-H stretch results in the highest dissociation probability and alignment along the surface normal in the lowest reactivity. The largest alignment contrast between the maximum and minimum reactivity is observed for Ni(110), which has its surface atoms arranged in close-packed rows separated by one layer deep troughs. For Ni(110), we also probed for alignment effects relative to the direction of the Ni rows. In-plane C-H stretch alignment perpendicular to the surface rows results in higher reactivity than parallel to the surface rows. The alignment effects on Ni(110) and Ni(100) are independent of incident translational energy between 10 and 50 kJ/mol. Quantum state-resolved reaction probabilities are reported for CH(4)(ν(3)) on Ni(110) for translational energies between 10 and 50 kJ/mol. 相似文献
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A new vic-dioxime ligand containing 1,3-dioxolane ring and 1,4-diaminobutane, (E,E)-N-hydroxy-2-(hydroxyimino)-N-(4-{[(2-phenyl-1,3-dioxolan-4-yl)methyl]amino}butyl)ethanimidamide (H2L) and the metal mononuclear complexes with a 1 : 2 and 1 : 1 metal–ligand ratio have been prepared with chloride salts Co(II), Ni(II), Cu(II), and Zn(ll) in EtOH. The structures of the ligand and its complexes have been established by microanalyses, IR, UV-VIS, 1H and 13C NMR spectra, elemental analyses, and conductivity and magnetic susceptibility measurements. Also their thermal behavior has been studied by the TGA analysis. 相似文献
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本文阐明了量子化学从头计算中的Gauss积分函数Fm(z)用递推公式计算时误差传递和变化的定量规律.提出了向上和向下递推相结合进行Fm(z)系列计算的最优方案,它保证绝对误差在递推过程中只减不增,对递推基项无附加的精度要求,可用于改进各种Fm(z)程序.本法与Schaad公式相结合,用于P、d、f和g型Gauss函数的计算,可分别节约加法运算40%以上和乘法、指数运算60%以上. 相似文献
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The infrared (IR) spectra of liquid, gaseous and solid states as well as the liquid and solid phases Raman ones of the pure (Z,Z)-2, 4-hexadiene are recorded for the first time between 3100–50 cm−1. Furthermore, the IR spectra of the gaseous and solid states and the solid Raman ones have been obtained (3100-50 cm−1) for the (E,E) and (Z,E) isomers. A comparison between the present and our previous results for the liquid phase have enabled us to complete and confirm our previous assignment and to conclude that the planar s-trans conformation is prevailing in the three physical states under conditions used in this work. 相似文献
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Ramadan M El Bahnasawy Abdou S El-Tabl Mohamad M E Shakdof Noran M Abd El-Wahed 《无机化学学报》2014,30(6):1435-1450
合成了Cu(Ⅱ),Ni(Ⅱ),Co(Ⅱ),Mn(Ⅱ),Zn(Ⅱ)和Cd(Ⅱ)的乙基3-(2-氨硫化亚肼基)-2-(羟胺基)丁烯酸酯配合物(H2L)并用元素分析,DTA热分析,IR,UV-Vis,1H-NMR,质谱,顺磁共振以及磁矩,电导率测量等对合成的配合物进行表征。摩尔电导率测量结果证明合成的配合物为非电解质。光谱数据表明配体分别表现为一元的三齿配体,一元的二齿配体,中性的二齿配体,中性的三齿配体,一元的四齿配体或二元的四齿配体通过席夫碱的氮原子,氨基硫脲中的氮原子,肟中的氮原子和硫酮中的硫原子与金属离子键合生成围绕金属离子的四面体或平面正方形构型。固态Cu(Ⅱ)(2),(3),(4)和(5)的配合物顺磁共振谱表明其为轴向对称,但(10~15)的配合物却为各向异性。配体和配合物(2),(3),(10),(13),(16)和(19)由于它们对乳腺癌(MCF-7细胞系)和肝癌(HePG-2细胞系)的抑制作用而表现出潜在的抗癌活性。 相似文献
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The structural properties of a-Al(2)O(3)∕In(0.5)Ga(0.5)As, a-HfO(2)∕In(0.5)Ga(0.5)As, and a-ZrO(2)∕In(0.5)Ga(0.5)As interfaces were investigated by density-functional theory (DFT) molecular dynamics (MD) simulations. Realistic amorphous a-Al(2)O(3), a-HfO(2), and a-ZrO(2) samples were generated using a hybrid classical-DFT MD "melt-and-quench" approach and tested against the experimental properties. For each stack type, two systems with different initial oxide cuts at the interfaces were investigated. All stacks were free of midgap states, but some had band-edge states which decreased the bandgaps by 0%-40%. The band-edge states were mainly produced by deformation, intermixing, and bond-breaking, thereby creating improperly bonded semiconductor atoms. The interfaces were dominated by metal-As and O-In∕Ga bonds which passivated the clean surface dangling bonds. The valence band-edge states were mainly localized at improperly bonded As atoms, while conduction band-edge states were mainly localized at improperly bonded In and Ga atoms. The DFT-MD simulations show that electronically passive interfaces can be formed between high-κ oxides dielectrics and InGaAs if the processing does not induce defects because on a short time scale the interface spontaneously forms electrically passive bonds as opposed to bonds with midgap states. 相似文献
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K. M. Turdybekov S. V. Lindeman T. V. Timofeeva Yu. T. Struchkov 《Chemistry of Natural Compounds》1991,27(3):288-291
The relative stabilities of the four possible conformers in the various types of linkage of the 10-membered and lactone rings (E,E)-1(10),4-germacrano-lides have been established from the results of a calculation by the method of molecular mechanics. The possibility of the realization of these conformers in linear and nonlinear (E,E)-germacranolides has been evaluated.A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR, Moscow. Trnslated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 335–339, May–June, 1991. 相似文献
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《Analytical letters》2012,45(10):2323-2334
Abstract The title compound (TXB2?M) is a quantitative index of thromboxane A2 synthesis in the human. We developed a method for its determination in urine based on the use of the 13C-labeled methyl ester derivative of the analyte as internal standard and GC-EIMS. the interassay coefficient of variation (CV) was 5.3% (N=4) and the intraassay CV ranged from 2.6 to 8.2% (N=3). the equation of the regression curve correlating the amounts added and recovered was Y=0.932X+3.99 (R=0.9947). the relative recovery of TXB2?M from nine urine specimens was 99.8 ± 2.8% (mean ± SEM). the mean (±SD) 24-hr output in six healthy male subjects was 1371 ± 307 ng, and in six females it was 1176 ± 418 ng. Concentrations as low as 200 pg/ml of urine can easily be measured with this procedure if one uses 50 ml of urine for the analysis. 相似文献