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991.
The principle of a Weissenberg camera is applied to surface crystallographic analysis by reflection high-energy electron diffraction. By removing inelastic electrons and measuring hundreds of patterns as a function of sample rotation angle phi, kinematical analysis can be performed over a large volume of reciprocal space. The data set is equivalent to a three-dimensional stack of Weissenberg photographs. The method is applied to analysis of an Si(111)-square root of 3 x square root of 3-Ag surface, and the structural data obtained are in excellent agreement with the known atomic structure. 相似文献
992.
Honami Tamaya Yuto Torii Takumi Ishikawa Prof. Dr. Hideyuki Nakano Dr. Toshifumi Iimori 《Chemphyschem》2019,20(19):2531-2538
We report absorption, fluorescence, and Raman spectroscopy of 7,7,8,8-tetracyanoquinodimethane (TCNQ) in a variety of solvents. The fluorescence quantum yields (QYs) of linear alkane solutions are similar to one another, but QY is shown to acutely decrease in other solvents with increasing polarities. The slope of the solvatochromic plot of absorption maxima is inverted from negative to positive with an increase in solvent polarity. A significant change in the frequency of carbon-carbon double bond stretching modes is not observed in Raman spectra of TCNQ in different solvents. The molar absorption coefficient is determined to calculate the oscillator strength of the absorption band. The radiative decay rate constant calculated from the oscillator strength is approximately ten times larger than that elucidated from the fluorescence lifetime and QY. These spectroscopic parameters reveal that the relaxation occurs from a Franck-Condon excited state to a distinct fluorescence emissive state with a smaller transition dipole moment. 相似文献
993.
Maximo Larry Lopez Caceres Sayako Nakano Juan Pedro Ferrio Mika Hayashi Takeshi Nakatsuka Masaki Sano 《Isotopes in environmental and health studies》2018,54(5):494-507
The March 2011 Mega-Tsunami in eastern Japan damaged at different degrees the black pine (Pinus thunbergii) forests along the coast. In order to evaluate the recovery of black pine four years later, tree-ring samples from 9 trees for the period 2002–2014 were analyzed for ring growth and stable isotopes (δ13C, δ15N and δ18O). The results showed that annual tree-ring width decreased approximately 70?% from the year 2011 to 2014 compared to the period previous to the tsunami (2002–2010). The multiple isotopic analyses showed that the reduction in growth was caused by soil salinity that prompted stomatal closure and an abrupt increase of tree-ring δ13C. Sea water deposition in the soil did not affect tree-ring δ18O values. Two years after the tsunami, decreasing tree-ring δ13C values caused by apparently photosynthetic recovery did not translate into radial tree-growth, indicating a possible shift in carbon allocation to foliage and mainly roots as a defense mechanism to sodium toxicity. The dual δ13C-δ18O model explains neither the limited growth nor the subsequent recovery in δ13C. Similarly tree-ring δ15N indicated that there was no difference in nitrogen availability before and after the tsunami, suggesting that nutrients were not a limitation but rather soil salinity. 相似文献
994.
Y. Sobajima S. Nakano M. Nishino Y. Tanaka T. Toyama H. Okamoto 《Journal of Non》2008,354(19-25):2407-2410
Microstructures of microcrystalline silicon (μc-Si) deposited at a high-growth-rate have been investigated in order to apply to the photovoltaic i-layer. μc-Si films were prepared by very-high-frequency (100 MHz) plasma-enhanced chemical vapor deposition at 180 °C. High growth rates of 3.3–8.3 nm/s have been achieved utilizing high deposition pressures up to 24 Torr and large input powers. Applying μc-Si to n–i–p junction solar cells, as the optimum result in this experimental series, a conversion efficiency of 6.30% (JSC: 22.1 mA/cm2, VOC: 0.470 V, and FF: 60.7%) has been achieved employing the i-layer deposited at 8.1 nm/s. Raman scattering and X-ray diffraction measurements revealed the crystalline volume fraction of around 50% with the (2 2 0) crystallographic preferential orientation, respectively. The cross-sectional transmission electron microscope image shows densely columnar structure grown directly on the underlying n-layer. These structural features are basically in good agreement those of low-growth-rate μc-Si used for a high efficiency solar cell as previously reported, implying advantages of the use of high pressures with regard to providing the photovoltaic i-layers. Finally, the implication is discussed from the photovoltaic performance as a function of the crystalline volume fraction of i-layer, and current problems in improving the photovoltaic performance are extracted. 相似文献
995.
The filling-factor-dependent plateau-type dispersion of the long-wavelength magnetoplasmon in high-mobility two-dimensional electron system observed by Holland et al. [Phys. Rev. Lett. 93, 186804 (2004)10.1103/PhysRevLett.93.186804] can be explained by the well-established semiclassical dispersion, by adopting the electron reservoir hypothesis previously proposed in order to explain the integer quantum Hall effects. 相似文献
996.
Tadashi Watanabe 《Physics letters. A》2008,372(4):482-485
Free-decay oscillations and rotations of a levitated liquid droplet are simulated numerically, and the frequency shift of drop-shape oscillations is studied. It is shown for an oscillating-rotating liquid droplet that the oscillation frequency decreases as the amplitude of drop-shape oscillations increases, while it increases as the rotation rate increases. The pressure difference between the equator and the pole of the droplet is found to correspond to the frequency shift. It is also found that the relation between the amplitude and the rotation rate is linear both for zero frequency shift and for zero pressure difference. 相似文献
997.
Yamada K Shimizu T Asanuma M Yamazaki T Yokoyama S 《Solid state nuclear magnetic resonance》2008,33(1-2):25-30
We have presented a solid-state 17 O NMR study of [13C, 17 O]-L-alanine. Using the experimental results for the 13C-17 O dipolar vector and Euler angles, the absolute orientations of 17 O chemical shielding (CS) and electric-field-gradient (EFG) tensors with respect to the molecular frame can be determined for L-alanine. The present results suggest that the intermediate EFG tensor components, VYY, lie in the carboxylate plane and parallel to the C-O bond directions, while the least shielded components, delta11, and the intermediate CS tensor components, delta22, roughly lie in the molecular plane and the direction of delta22 components are approximately 38 degrees and 25 degrees off the C-O bonds for O1 and O2, respectively. These results are in reasonable agreement with those of our quantum chemical calculations reported previously. 相似文献
998.
Hiroyuki Nakano Kaoru Dokko Masanori Hara Yasuhiro Isshiki Kiyoshi Kanamura 《Ionics》2008,14(2):173-177
A novel electrode system composed of three-dimensionally ordered macroporous (3DOM) Li1.5Al0.5Ti1.5(PO4)3 (LATP) and LiMn2O4 was fabricated by the colloidal crystal templating method and sol–gel process. A LATP nanoparticle for the fabrication of
3DOM-LATP was prepared by a sol–gel process. A suspension containing polystyrene (PS) beads and the LATP nanoparticles was
filtrated by using a polycarbonate filter to accumulate PS beads and LATP. The accumulated PS beads had a close-packing structure,
and the void between PS beads was filled with LATP nanoparticles. 3DOM-LATP was obtained by heat treatment of the accumulated
composite. Li–Mn–O sol was injected by a vacuum impregnation process into the macropores of 3DOM-LATP and then was heated
to form three-dimensionally ordered composite materials consisting of LiMn2O4 and LATP. The formation of the composite between 3DOM-LATP and LiMn2O4 were confirmed with scanning electron microscopy and X-ray diffraction method. The prepared composite electrode system exhibited
a good electrochemical performance.
Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15, 2007. 相似文献
999.
Nakai Y Nakano Y Azuma T Hatakeyama A Kondo C Komaki K Yamazaki Y Takada E Murakami T 《Physical review letters》2008,101(11):113201
We report the Autler-Townes doublet demonstrating a novel type of coherent interaction of atoms not with photons but with a periodic crystal field when the atom is in flight through a crystal at high velocity. It was observed by the nonoptical X-VUV (vacuum-ultraviolet) double resonance of three-dimensional resonant coherent excitation with good coherence. The states strongly coupled in the VUV region were probed by the excitation in the x-ray region. The characteristic spectra are well interpreted by an analogy of the dressed atom concept often adopted for the atom-photon interaction. 相似文献
1000.
Hiroshi Nakano Masahiro Mori Yorihiko Tsunoda Susumu Matsuo 《Journal of magnetism and magnetic materials》2008
A kink was observed near 20 kOe in the field dependence of the magnetization in a single-grained α-Mn without a magnetic hysteresis below the Neel temperature in an accurate magnetization measurement below 80 kOe. It was observed along [1 0 0], [1 1 0] and [1 1 1] crystallographic directions. The field dependence of the magnetization above 40 kOe extrapolates to positive finite magnetization at null field. The kink suggests a weak metamagnetism induced by the external magnetic field. A small but clear anisotropy was observed between the weak-field susceptibilities along [1 0 0] and [1 1 0]/[1 1 1] directions. A previously reported large susceptibility anomaly was not affirmed between 90 and 270 kOe. 相似文献