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41.
The potential barriers for the internal rotation of silole dimers are studied theoretically using the ab initio molecular orbital method at the RHF/6-31G** level of calculations. In 2,2′-bisilole, it is found that the anti-conformation is the most stable structure in the ground state and that the potential barrier height for rotation over the perpendicular conformation is 3.3 kcal/mol. © 1996 John Wiley & Sons, Inc. 相似文献
42.
T. Ohachi N. Yamabe H. Shimomura T. Shimamura O. Ariyada M. Wada 《Journal of Crystal Growth》2009,311(10):2987-2991
Production and measurement of active nitrogen atoms (N+N*), which consist of ground state nitrogen atoms N and excited state nitrogen atoms N*, in an inductively coupled radio frequency discharge for the growth of group III nitrides and their alloys using a molecular beam epitaxy (MBE) were studied. Two discharge modes of the low brightness (LB) and the high brightness (HB) used in this study to produce excited nitrogen molecules (N2*) and dissociated active nitrogen atoms (N+N*). The flux of (N+N*) was measured by a Langumuir-like electrode due to the self-ionization of adsorbed (N+N*) on a negatively biased electrode. The self-ionization, which emits electrons from (N+N*), forms an atom current and is confirmed using different electrodes such as Pt and CuBe and different electrode area. The atom current was calibrated by the grown GaN thickness in a VG80H MBE machine. The calibrated flux of (N+N*) per atom current in the VG80H machine is 5.5×10−4 ML/s/nA, where ML is monolayer. The atom current is useful to monitor the flux of chemically active nitrogen atoms N+N* for growth of group III nitrides and their alloys. Activity modulation migration enhanced epitaxial growth (AM-MEE) was demonstrated as an application of the measurement of atom current for the growth of the group III nitrides. 相似文献
43.
44.
Mass spectrometric monitoring of oxidation of aliphatic C6–C8 hydrocarbons and ethanol in low pressure oxygen and air plasmas 下载免费PDF全文
Dilshadbek T. Usmanov Lee Chuin Chen Kenzo Hiraoka Hiroshi Wada Hiroshi Nonami Shinichi Yamabe 《Journal of mass spectrometry : JMS》2016,51(12):1187-1195
Experimental and theoretical studies on the oxidation of saturated hydrocarbons (n‐hexane, cyclohexane, n‐heptane, n‐octane and isooctane) and ethanol in 28 Torr O2 or air plasma generated by a hollow cathode discharge ion source were made. Ions corresponding to [M + 15]+ and [M + 13]+ in addition to [M ? H]+ and [M ? 3H]+ were detected as major ions where M is the sample molecule. The ions [M + 15]+ and [M + 13]+ were assigned as oxidation products, [M ? H + O]+ and [M ? 3H + O]+, respectively. By the tandem mass spectrometry analysis of [M ? H + O]+ and [M ? 3H + O]+, H2O, olefins (and/or cycloalkanes) and oxygen‐containing compounds were eliminated from these ions. Ozone as one of the terminal products in the O2 plasma was postulated as the oxidizing reagent. As an example, the reactions of C6H14+? with O2 and of C6H13+ (CH3CH2CH+CH2CH2CH3) with ozone were examined by density functional theory calculations. Nucleophilic interaction of ozone with C6H13+ leads to the formation of protonated ketone, CH3CH2C(=OH+)CH2CH2CH3. In air plasma, [M ? H + O]+ became predominant over carbocations, [M ? H]+ and [M ? 3H]+. For ethanol, the protonated acetic acid CH3C(OH)2+ (m/z 61.03) was formed as the oxidation product. The peaks at m/z 75.04 and 75.08 are assigned as protonated ethyl formate and protonated diethyl ether, respectively, and that at m/z 89.06 as protonated ethyl acetate. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
45.
The nominal stress–strain relationships of industrial rubber materials under multiaxial deformation are essential for precisely determining the constitutive laws of those materials. This paper proposes a new method for precisely estimating the nominal stress–stretch relationships of carbon-black-filled styrene butadiene rubbers (SBRs) under uniaxial tension, pure shear, and equibiaxial tension by using an in-plane biaxial tensile tester. The proposed method employs sheet-shaped rubber samples with notches for the pure-shear and equibiaxial tension tests to mitigate the influence of non-uniform deformation around the clamps. Finite element analysis and biaxial tensile tests were performed to verify the effectiveness of the proposed method. Performance evaluations based on both numerical calculations and experiments revealed that the proposed method enabled the precise calculation of the nominal stress–stretch relationship for uniform deformation from a tensile load and deformation of the reference area defined at the center of the samples. 相似文献
46.
Density functional theory (DFT) calculations were employed to investigate the electronic properties of an H-atom terminated graphene patch (hydrographene) smaller than a rhombic C96H26 structure with zigzag edges. Depending on shapes and sizes of hydrographenes, some hydrographenes have the triplet ground state where unpaired electrons are localized on their zigzag edges. The stability of the triplet spin state is diminished, decreasing the hydrographene sizes. The existence of the localized spin densities allows triplet dioxgen to bind into a hydrographene. According to the DFT calculations, the energetics of the dioxygen bindings is negatively influenced by downsizing hydrographenes, as well as depends on their shapes. The size-and shape-dependences of the dioxygen bindings reflect from the stability of the triplet state of a hydrographene, because its localized unpaired electrons can be utilized to be attached to an unpaired electron of triplet dioxygen. 相似文献
47.
K. Tanaka T. Shichiri K. Yoshizawa T. Yamabe S. Hotta W. Shimotsuma J. Yamauchi Y. Deguchi 《Solid State Communications》1984,51(7):565-567
ESR measurements have been performed on samples of poly(3-methylthienylene, poly(3-methylthienylene) perchlorate, and poly(3-methylthienylene) iodide. The ESR lines observed are concluded to come from defects in the π-conjugated system. It is deduced that the current carriers in the doped film are spinless and the role of bipolarons in the conduction mechanism is suggested. 相似文献
48.
[reaction: see text] N,N-bis[4-(dimethylamino)phenyl]-N,N'-dimethyl-1,3-benzenediamine was prepared in order to investigate the corresponding Würster blue-based di(cation radical). The generated diradical was found to be a ground-state triplet, and moreover, the observed ESR spectrum had no definite fine structure, suggesting a mixture of some conformers. 相似文献
49.
Masamori Yamabe Harumichi Shimizu 《Journal of polymer science. Part A, Polymer chemistry》1971,9(10):2901-2914
The γ-ray-induced reaction of ethylene with carbon tetrachloride in cyclohexane was carried under a pressure of 30 kg/cm2 and at a temperature of 20°C. The liquid and the solid products were obtained. Their structures were discussed on the basis of infrared absorption spectra and differential thermal analysis curves. The liquid product is considered to be ethylene–carbon tetrachloride telomer. The solid product consists of three components, differing slightly in molecular structure and molecular weight. To clarify the reaction process, some runs with the ethylene–cyclohexane–(ethylene–carbon tetrachloride telomer) system were also carried out. In this system, only solid product was obtained. Thus, it is concluded that the reaction proceeds stepwise, the first step being the telomerization reaction and the second the graft polymerization of ethylene onto the telomer produced in the first step. 相似文献
50.
Kazuyoshi Tanaka Hiromi Kobayashi Mayumi Okada Masahiro Kobashi Tokio Yamabe 《International journal of quantum chemistry》1992,42(1):45-54
Electronic-phase transition associated with the singlet instability problem of the Hartree-Fock solution of the extended system is studied employing the metallic trans-polyacetylene. Concerning the eigenstates of the stability matrix set up for the crystal orbitals at the Fermi level, classification of the electronic phases is attempted and the origin of their emergence in relation to the interelectronic interaction is discussed. 相似文献