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排序方式: 共有439条查询结果,搜索用时 15 毫秒
291.
Naoyuki Koike 《Results in Mathematics》2001,39(3-4):230-244
In this paper, we define an equiaffine immersion of general codimension and the Lipschitz-Killing curvature for the immersion. Furthermore, we prove theorems of Gauss-Bonnet type and Chern-Lashof type for the immersion. 相似文献
292.
Shigefusa F. Chichibu Takuya Ohmori Naoyuki Shibata Takahiro Koyama Takeyoshi Onuma 《Journal of Physics and Chemistry of Solids》2005,66(11):1868-1871
Greenish-white electroluminescence (EL) was observed from the heterojunction light-emitting diodes (LEDs) composed of p-type (001) CuGaS2 chalcopyrite semiconductor epilayers and preferentially (0001)-oriented polycrystalline n-type ZnO thin films. The CuGaS2 layers were grown on a (001) GaP substrate by metalorganic vapor phase epitaxy and the ZnO films were deposited by the surface-damage-free helicon-wave-excited-plasma sputtering method. The n-ZnO/p-CuGaS2 LED structure was designed to enable an electron injection from the n-type wider band gap material forming a TYPE-I heterojunction. The EL spectra exhibited emission peaks and bands between 1.6 and 2.5 eV, although their higher energy portions were absorbed by the GaP substrate. Since the spectral lineshape resembled that of the photoluminescence from identical CuGaS2 epilayers, the EL was assigned to originate from p-CuGaS2. 相似文献
293.
Naoyuki Amemiya Kengo Miyamoto Shun-ichi Murasawa Hideki Mukai Kazuya Ohmatsu 《Physica C: Superconductivity and its Applications》1998,310(1-4):30-35
AC losses in Bi-2223 superconducting tapes carrying AC transport current and/or exposed to DC or AC magnetic field are calculated with a numerical model based on the finite element method. Superconducting property is given by the E–J characteristic represented by a power law using equivalent conductivity. First, transport loss and magnetization loss are calculated numerically and compared with measured values. The calculated losses almost agree with the measured losses. Frequency dependencies of calculated and measured transport losses are compared with each other. Next, the influence of DC external magnetic field on the transport loss is studied. DC external magnetic field reduces n that is an exponent in the power law connecting resistivity and current density. The numerically calculated transport loss increases with increasing DC magnetic field. Finally, the total loss of superconducting tape carrying AC transport current in AC magnetic field is calculated. In the perpendicular magnetic field, the calculated total loss is lager than the sum of the transport loss and the magnetization loss, while they almost agree with each other in the parallel magnetic field. 相似文献
294.
Naoyuki Amemiya Shun-ichi Murasawa Nobuya Banno Kengo Miyamoto 《Physica C: Superconductivity and its Applications》1998,310(1-4):16-29
Superconducting properties of superconducting wires as well as the influence of their composite structure and twisting should be taken into account for their numerical modeling for AC loss calculations. Furthermore, complicated electromagnetic conditions in electrical apparatuses under which superconducting wires are used influence their AC loss properties; superconducting wires carry their transport current and are exposed to the external magnetic field whose direction and magnitude vary spatially. A series of numerical models of superconducting tapes based on the finite element method has been developed. In each model, some of the above-mentioned factors that could influence the AC loss properties are taken into account. The models are formulated with the current vector potential and the scalar magnetic potential (T–Ω method). Superconducting property is given by the E–J characteristic represented by a power law. The current distributions in non-twisted and twisted superconducting tapes carrying their transport current and/or exposed to the external magnetic field are calculated with these models to estimate their AC loss. The current distribution in a short piece of superconducting tape exposed to AC magnetic field is also calculated. 相似文献
295.
The relationship between the molecular orientation of a rubbed polyimide film (alignment layer) and that of mesogens in a photopolymerized liquid crystal (LC) coated on the film has been investigated using optical measurements. LC monomers were deposited on the alignment layer and were aligned in one direction. The LC monomers were subsequently photocured. Alignment layers under various rubbing conditions were prepared. It was found that the inclination angle of the refractive index ellipsoid and the optical retardation of photopolymerized LC films are strongly related to the optical anisotropy of the rubbed polyimide film. The photopolymerized LC film exhibited high optical anisotropy when alignment layers with an inclination angle of the refractive index ellipsoid smaller than 6° were used. 相似文献
296.
M. Nagase S. Horiguchi A. Fujiwara Y. Ono K. Yamazaki H. Namatsu Y. Takahashi 《Applied Surface Science》2002,190(1-4):144-150
The embedded Si structure formed by pattern-dependent oxidation (PADOX) in single-electron device (SED) is analyzed by novel microscopic methods using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface charge imaging SEM reveals the outline of the embedded Si nanowire of the electrically-measured SED. The size of the wire in the device is small enough to make a potential barrier caused by the quantum mechanical size effect. The result of the Si height in the oxidized structure estimated by AFM indicates that the huge stress induced by oxidation is applied to the narrow Si wire. The experimental results support the theoretical model of the SED fabricated by PADOX that the potential profile responsible for the SED operation is produced by two effects, the quantum mechanical size effect and the strain-induced bandgap reduction. 相似文献
297.
Miyuki Harada Mitsukazu Ochi Masayuki Tobita Tohru Kimura Tsukasa Ishigaki Naoyuki Shimoyama Hisashi Aoki 《Journal of Polymer Science.Polymer Physics》2004,42(5):758-765
During the curing process of a liquid‐crystalline epoxy resin, a relatively strong magnetic field was applied, and the thermomechanical properties of the cured resin were investigated. The network orientation and mechanical properties of the cured system were evaluated with wide‐angle X‐ray diffraction, dynamic mechanical analysis, and fracture toughness testing. The cured system was found to have an anisotropic network structure, which arranged along the applied field, and the anisotropy was reflected in the thermomechanical properties. In particular, the fracture toughness of the system dramatically increased when the network chains were arranged across the direction of the crack propagation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 758–765, 2004 相似文献
298.
A study was made of the autooxidation of benzoin in organic-aqueous sodium hydroxide emulsions in the presence of several quaternary ammonium salts. The rate of the reaction was found to be accelerated by these salts, probably by ion pair extraction. In pyridine and acetonitrile systems the reaction was almost exclusively the formation of benzoate. Neither benzil nor benzaldehyde were intermediates in the oxidation process. The rate law for the reaction was found to be which led to the conclusion that the rate-determining step in the catalyzed pathway was the reaction of oxygen with the ion pair: 相似文献
299.
K. Kunimori H. Horiguchi S. Tsuchiya 《Journal of Quantitative Spectroscopy & Radiative Transfer》1978,19(2):127-133
The integrated intensity of the fundamental vibration-rotation band of NO and the pressure-broadening parameters of NO with various foreign gases have been determined at room temperature by measuring the resonance absorption of the infrared emission line of the NO fundamental. The Hg photo-sensitized vibrational excitation of NO was utilized to obtain a light source for the NO fundamental. in which the individual rotational lines could be described in terms of the Doppler line profile at room temperature. The total band intensity was found to be 122 ± 6 cm-2 atm-1, and the collision-broadened full-widths at half maximum in CO2, N2, Ar, H2 and He gases were 0.10, 0.086, 0.059, 0.086 and 0.078 cm-1 atm-1, respectively. 相似文献
300.