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51.
52.
M. Nakayama T. Nakanishi Z. S. Piao H. Nishimura M. Takahashi N. Egami 《Physica E: Low-dimensional Systems and Nanostructures》2000,7(3-4)
We have investigated the excitonic properties of In0.15Ga0.85As/GaAs strained single quantum wells by using photoreflectance spectroscopy and a variational calculation method. We clearly detected the photoreflectance signal of the type-II light-hole exciton, which consists of an electron confined in the InGaAs layer and a light hole located in the thick GaAs layer, in addition to the type-I heavy-hole exciton confined in the InGaAs layer. The calculated results of the overlap integral of the envelope function in the type-II light-hole exciton predict that the oscillator strength is remarkably enhanced with decreasing the InGaAs-layer thickness. This is demonstrated by the layer-thickness dependence of the photoreflectance intensity of the type-II light-hole exciton. 相似文献
53.
Takashi Yasui Nozomu Komatsu Kazuki Egami Hiromichi Yamada Akio Yuchi 《Analytical sciences》2007,23(8):1011-1014
Bidentate and tridentate heterocyclic azo compounds with and without a long alkyl chain were prepared and examined for cation exchange chromatography of manganese, zinc, and cadmium; these ions could not be separated by reversed phase HPLC following precolumn derivatization with heterocyclic azo compounds owing to the dissociation of the complexes. The newly prepared azo compounds having a long alkyl chain favorably orientate in the reversed-phase stationary phase such that the coordinating parts of the ligand may make contact with metal ions in the mobile phase. Bidentate ligands showed sharp peaks but almost no resolution of manganese and cadmium. A tridentate ligand strongly retained all the three metal ions, which could be separated within 10 min by a competing ligand and by optimizing the pH. 相似文献
54.
Egami H Kamisuki S Dodo K Asanuma M Hamashima Y Sodeoka M 《Organic & biomolecular chemistry》2011,9(22):7667-7670
A cobalt-phosphine complex supported on PS-PEG beads was found to react with a propargyl carbamate tag, and the tagged molecules immobilized on the beads could be released by acidic treatment through the Nicholas reaction pathway. These reactions work in aqueous media at 4 °C, so that this catch and release procedure is compatible with conditions generally used in biochemical experiments. 相似文献
55.
We have proposed the fabrication of high-contrast-moth-eye structure using continuous wave (CW) laser. Nonlinear-optical reaction time constant of the photoresist can be controlled by manipulating the exposure intensity and scanning speed of the laser. As a result, shortening the time constant in the intense beam area and lengthening that in the weak beam area compared with the scanning speed, we can limit the exposed area. 相似文献
56.
Chikahiro Egami 《Nonlinear Analysis: Real World Applications》2009,10(1):494-505
This paper considers a nonautonomous Lotka–Volterra type multispecies competitive system with weak Allee effect and delays. The model has the intraspecific competition terms defined by sign changing functions which depend on population density monotonically and time periodically. An existence theorem of positive periodic solutions is established using the coincidence degree theory. Furthermore, for the case of constant delays, a sufficient condition for the positive periodic solution to be globally attractive is proved with the Lyapunov method so that the system attains permanence. 相似文献
57.
We describe the oscillatory crack propagation for small propagation velocities at the atomistic scale that was recently observed for brittle metallic glasses [G. Wang, Y.T. Wang, Y.H. Liu, M.X. Pan, D.Q. Zhao, W.H. Wang, Appl. Lett. 89 (2006) 121909; G. Wang, D.Q. Zhao, H.Y. Bai, M.X. Pan, A.L. Xia, B.S. Han, X.K. Xi, Y. Wu, W.H. Wang, Phys. Rev. Lett. 98 (2007) 235501]. Based on a simple model of crack propagation [Y. Braiman, T. Egami, Phys. Rev. E, 77 (2008) 065101(R)], we derived and analyzed expressions for the feature size, oscillation period, and maximum strain accumulated in the material. 相似文献
58.
M. Fähnle G. Herzer T. Egami H. Kronmüller 《Journal of magnetism and magnetic materials》1981,24(2):175-178
A mean field theory with correlations in space and time is proposed which implicitly takes into account the effect of thermal spin fluctuations. The theory describes the kinetic critical slowing down of the relaxation of the magnetization near the ferromagnetic phase transition in crystalline and amorphous ferromagnets. Furthermore, it provides an explanation for the large temperature range of apparent “critical” behaviour as observed experimentally for the paramagnetic susceptibility of amorphous ferromagnets. 相似文献
59.
60.
Shimizu H Onitsuka S Egami H Katsuki T 《Journal of the American Chemical Society》2005,127(15):5396-5413
Chiral (nitrosyl)ruthenium(salen) complexes were found to be efficient catalysts for aerobic oxidative desymmetrization of meso-diols under photoirradiation to give optically active lactols. The scope of the applicability of this reaction ranges widely from acyclic diols to mono-cyclic diols, although fine ligand-tuning of the ruthenium(salen) complexes was required to attain high enantioselectivity (up to 93% ee). In particular, the nature of the apical ligand was found to affect not only enantioselectivity but also kinetics of the desymmetrization reaction. Spectroscopic analysis of the oxidation disclosed that irradiation of visible light is indispensable not only for dissociation of the nitrosyl ligand but also for single electron transfer from the alcohol-bound ruthenium ion to dioxygen. 相似文献