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941.
942.
M. Nakano H. Fujita M. Takahata S. Kiribayashi K. Yamaguchi 《International journal of quantum chemistry》2001,84(6):649-659
We investigate the microscopic third‐order nonlinear optical properties, i.e., the second hyperpolarizabilities (γ), of two different sizes of molecular aggregates with a dendritic, i.e., Bethe‐lattice, structure. One possesses a nonfractal structure, while the other has a fractal structure. The aggregate is treated in a two‐exciton model composed of two‐state monomers coupled to each other by the dipole–dipole interaction. The off‐resonant γ of the aggregates are calculated by the numerical Liouville approach, including relaxation effects. The total γ value is partitioned into the contribution of virtual exciton generation, and its spatial contribution to γ is analyzed in relation to the virtual excitation processes in the perturbation theory. It is found that the intermolecular‐interaction effect enhances both one‐ and two‐exciton‐generation contributions, while the relaxation effect reduces those, although the one‐ and two‐exciton‐generation contributions have mutually opposite signs. From the comparison of spatial contributions to γ between the nonfractal and fractal aggregates, an enhancement of the contribution to γ from the periphery to the core is observed in the fractal structure, while such a feature is not observed in the nonfractal structure. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001 相似文献
943.
张高龙 叶沿林 江栋兴 郑涛 李智焕 李湘庆 吴翠娥 陈志强 胡青元 庞丹阳 王佳 A.Ozawa Y.Yamaguchi R.Kanungo D.Fang I.Tanihata 《中国物理 C》2005,29(10):940-943
在25MeV/u 6He轰击9Be靶的反应中,用探测器望远镜测得氚碎片,得到了5个角度的能谱,经过仔细的分析取得了高能直接破碎成分的角分布.利用Serber模型进行了破碎反应的理论计算,证实了实验中高能成分的t来自于6He的直接破碎反应.利用Fermi破碎模型计算了6He中各破碎反应道基于相空间的百分比产额,进而估算出6He初态中t+t结构的概率约占1/3, 而4He核心加价中子的组态约占2/3. 相似文献
944.
The authors discuss a method for estimating and/or predicting the listening score and two psychological impressions of speech audibility and annoyance, when listening to audio signals, in an actual noise environment. The method introduced the instantaneous spectral distance that reflects the relationship between the spectral level of the speech peaks and that of noise within a short time scale. The validity and the applicability of the proposed method were confirmed experimentally, and reasonable results were obtained. Specifically, it is necessary to predict a psychological impression of the noise as a whole over a long period of time, after a certain amount of exposure to noise, taking the period of higher sound pressure level of the noise into consideration. 相似文献
945.
Keiji Takeda Hiroko Tokoro Fumiyoshi Hakoe Akira Yamaguchi Hatsumi Mori Hidehiko Ishimoto Takayoshi Nakamura Shinya Kuriki Shin-ichi Ohkoshi 《Polyhedron》2009,28(9-10):1746-1749
We have developed a high temperature superconductor (HTS) micro SQUID magnetometer for molecular-based magnets. By employing the dipole approximation, we verified the flux value of 40Φ0 from the saturation magnetic moment of the ferrimagnetic microcrystal of [Mn2(H2O)2(CH3COO)][W(CN)8] · 2H2O (15 × 15 × 13 μm). Considering the relative arrangement of the sample and the SQUID loop, including the influence of the film and grease, the calculated the flux values were Φ = 71Φ0 and 31Φ0 at distances of 20 and 30 μm between the sample bottom face and the SQUID plane, respectively. Thus, the experimentally obtained flux value is reasonable. 相似文献
946.
947.
948.
This study investigates the integration system of head (-to-trunk), eye (-to-head), and retinal position signals for hand
pointing. In experiment 1, subjects changed their head and eye positions and pointed at a fixated visual stimulus by using
an unseen pointer. In experiment 2, subjects fixated a visual stimulus and pointed at another visual stimulus. The results
show that the head and eye position signals contributed linearly to perceptual direction (experiments 1 and 2), and that the
coefficients of these signals decrease with peripheral vision and are smaller than the coefficient of the retinal position
signal (experiment 2). These results collectively suggest that the integration algorithm of the position signals might be
described by the linear summation equation and that the retinal position signal serves a more important role than the other
position signals in the visual system. 相似文献
949.
KENZO Yamaguchi TOMOHIRO Inoue MASAMITSU Fujii MASANOBU Haraguchi TOSHIHIRO Okamoto MASUO Fukui SHU Seki SEIICHI Tagawa 《中国物理快报》2007,24(10):2934-2937
Using numerical calculation, we examine the effects of gap distance of a pair of nano gap silver prisms with rounded corners on the local light intensity enhancement. Two peaks due to localized surface plasmon (LSP) excitation are observed in a wavelength range from 900nm to 300nm. The results demonstrate that peaks at a longer and a shorter wavelength corresponded to dipole-like and quadrupole-like LSP resonances, respectively. It is found that a gap distance up to 20 nm provides larger light intensity enhancement than that of a single silver nano prism with rounded corners. Furthermore, nano gap silver prisms are fabricated by direct focused ion beam processing, and we measure the scattering light spectrum of a pair of nano prisms by a confocal optical system. However, the two LSP peaks are not observed in visible range because the sizes of the nano gap and prisms are too large. 相似文献
950.
N. Toyosugi H. Yamada D. Minkov M. Morita S. Imai T. Yamaguchi 《Journal of synchrotron radiation》2007,14(2):212-218
The tabletop synchrotron light sources MIRRORCLE‐6X and MIRRORCLE‐20SX, operating at electron energies Eel = 6 MeV and Eel = 20 MeV, respectively, can emit powerful transition radiation (TR) in the extreme ultraviolet (EUV) and the soft X‐ray regions. To clarify the applicability of these soft X‐ray and EUV sources, the total TR power has been determined. A TR experiment was performed using a 385 nm‐thick Al foil target in MIRRORCLE‐6X. The angular distribution of the emitted power was measured using a detector assembly based on an NE102 scintillator, an optical bundle and a photomultiplier. The maximal measured total TR power for MIRRORCLE‐6X is Pmax? 2.95 mW at full power operation. Introduction of an analytical expression for the lifetime of the electron beam allows calculation of the emitted TR power by a tabletop synchrotron light source. Using the above measurement result, and the theoretically determined ratio between the TR power for MIRRORCLE‐6X and MIRRORCLE‐20SX, the total TR power for MIRRORCLE‐20SX can be obtained. The one‐foil TR target thickness is optimized for the 20 MeV electron energy. Pmax? 810 mW for MIRRORCLE‐20SX is obtained with a single foil of 240 nm‐thick Be target. The emitted bremsstrahlung is negligible with respect to the emitted TR for optimized TR targets. From a theoretically known TR spectrum it is concluded that MIRRORCLE‐20SX can emit 150 mW of photons with E > 500 eV, which makes it applicable as a source for performing X‐ray lithography. The average wavelength, = 13.6 nm, of the TR emission of MIRRORCLE‐20SX, with a 200 nm Al target, could provide of the order of 1 W EUV. 相似文献