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81.
The surface-induced valley-splitting theory by Sham and Nakayama is shown in the special case of a two-band model for the silicon band structure to be closely related to the electric break-through effect of Ohkawa and Uemura. Recent criticisms of our theory by Ohkawa are shown to be erroneous. 相似文献
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85.
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
86.
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
87.
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
88.
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
89.
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
90.
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