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101.
102.
Hamao Watanabe Kazuaki Higuchi Tomoko Goto Tsutomu Muraoka Jun Inose Masaaki Kageyama Yasuko Iizuka Masakatsu Nozaki Yoichiro Nagai 《Journal of organometallic chemistry》1981,218(1):27-39
In the presence of a catalytic amount of sodium methoxide, sym-dimethoxytetramethyldisilane was converted into α,ω-dimethoxypermethylpolysilanes, MeO(SiMe2)nOMe where n ? 3, at room temperature. On the other hand, similar treatment of the disilane in THF solution gave cyclic polysilanes, (Me2Si)n where n = 5–7. Decomposition of the disilane in the presence of diphenylacetylene afforded a trisilacyclopentene derivative under similar conditions. This compound was obtained also by the reaction between α,ω-dimethoxypermethylpolysilanes and diphenylacetylene in the presence of sodium methoxide. These cyclic products most likely were formed via permethyl polysilyl anion intermediates derived from α,ω-dimethoxypermethylpolysilanes. Also, the formation of α,ω-dimethoxypermethylpolysilanes could be elucidated in terms of the mechanism involving the base-assisted, concerted nucleophilic substitution or stepwise substitution by silyl anions, rather than the successive dimethylsilylene (Me2Si:) insertion reaction. 相似文献
103.
Sodium vapour in a sealed cell is irradiated by two counter-propagating but laterally displaced beams from the same laser, tuned to one of the hf components of the D1 line. Atoms pumped by the stronger beam, circularly polarized, precess in a transverse magnetic field, < 300 mG, during their passage to the weaker beam where their orientation is monitored. The observed signals are interpreted quantitatively. 相似文献
104.
Nakayama M Goto S Uchimoto Y Wakihara M Kitajima Y Miyanaga T Watanabe I 《The journal of physical chemistry. B》2005,109(22):11197-11203
Changes in the electronic structure of olivine Li(1-x)CoPO(4), 4.8 V positive electrode material for lithium ion batteries, were investigated using the X-ray absorption spectroscopy (XAS) technique. The threshold energy in the Co K-edge increased with electrochemical Li removal, indicating the oxidation of cobalt ions due to charge compensation. Moreover, P and O K-edge XAS showed a slight shift in threshold energy with Li removal. Although it is generally believed that the electrons of PO(4) polyanion do not contribute to the oxidation process, present experimental results indicate changes in the electronic structure around PO(4) units. Such results would be interpreted by the idea of the hybridization effect between the Co 3d and O 2p orbitals and of the polarization effect introduced by Li ions. 相似文献
105.
Nakayama M Wakihara M Kobayashi Y Miyashiro H 《The journal of physical chemistry. B》2005,109(30):14648-14653
The relationship between the Li arrangement and the electrochemical behavior has been examined as a function of composition x in electrochemically lithiated A-site deficient perovskite, Li(x)()La(1/3)NbO(3). The cell potential diagram and powder X-ray diffraction (XRD) study indicated that the Li ions are inserted into the vacant Perovskite A-site with an electrochemical reaction. In addition, the derivatives of the cell potential diagram showed three cathodic peaks, indicating a stepwise Li insertion mechanism takes place. Such a stepwise behavior would be ascribed to the changes in arrangement of inserted Li ions in the Perovskite lattice, since the XRD patterns of pristine La(1/3)NbO(3) showed that the La arrangement in La(1/3)NbO(3) was ordered along the c-axis, causing two kinds of A-site vacancies. To reveal the changes in the arrangement of Li ions, the entropy measurement of the reaction was performed by both the electrochemical and the calorimetric techniques. Moreover, the formation energy of the Perovskite structure with various Li arrangements was compared by using an ab initio calculation. The results of experiment and computation suggested that the electrochemical reaction proceeded via two kinds of superstructures of Li(1/6)La(1/3)NbO(3) and Li(1/2)La(1/3)NbO(3) due to the ordered arrangement of Li ions. 相似文献
106.
K.?MizoguchiEmail author S.?Fujita M.?Nakayama 《Applied Physics A: Materials Science & Processing》2004,78(4):461-464
We report the first observation of coherent phonons in crystalline lead phthalocyanine (PbPc) films grown on a (0001) sapphire substrate by using a pump–probe technique. Coherent phonon oscillations corresponding to intermolecular (lattice) vibrations in the PbPc film are observed in the frequency region from 1 to 5 THz. It is found that the intensities of coherent phonons are resonantly enhanced at the exciton energies of the Q band observed in the absorption spectrum. PACS 78.47.+p; 78.66.-w; 82.53.Xa; 78.40.Me 相似文献
107.
A layered nanocomposite with poly(diallyldimethylammonium), PDDA, intercalated between manganese oxide layers can be formed on a platinum electrode in a thin film form through a direct electrochemical route. The process involves a potentiostatic oxidation of aqueous Mn(2+) precursors in the presence of PDDA by applying a constant potential (+1.0 V vs Ag/AgCl). 相似文献
108.
Endonuclease BamHI mutants having an azophenylalanine residue in the dimer interface (azoAla-BamHI) were synthesized; while the activity was almost suppressed using trans-azoAla-BamHI, the cis-isomer generated with photoirradiation recovered its intrinsic activity. 相似文献
109.
In previous work on polarization-mode dispersion (PMD) measurement with an optical time-domain reflectometer with polarimetry (p-OTDR), scatterers were assumed to be a cloud of small spherical particles in a fiber. We have found that the p-OTDR waveforms were fitted well by modified Mueller matrices, assuming scattering by a cloud of nonspherical particles. We realized a PMD measurement based on the p-OTDR Jones matrix eigenanalysis (JME) method. The measured PMD was consistent with that of JME standard measurement with transmission-type polarimetry. 相似文献
110.
K. Nakayama H. Tazawa S. Okajima K. Kawahata K. Tanaka T. Tokuzawa Y. Ito 《International Journal of Infrared and Millimeter Waves》2003,24(9):1421-1430
A diagnostic system using short-wavelength far-infrared (FIR) lasers (40–70 m in wavelength) is now being developed for high density and large volume plasmas. In the wavelength region, a CVD-diamond is the excellent materials for optical windows of the laser and the plasma vessel and beam splitters of a multichannel interferometer. To design these optical elements, the optical constants (refractive index n, absorption coefficient and transmissivity T) of the CVD-diamond have been measured precisely by using FIR lasers of 48-, 57- and 71-m in wavelength. As an example, the result for 57.1511 m light is n = 2.383(1) ± 0.002, = 0.19 ± 0.05 cm-1 and T = 97.5 ± 1.5% at 1.023 mm in thickness. 相似文献