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101.
Jinfeng Yang Koichi Kan Nobuyasu Naruse Yoichi Yoshida Katsumi Tanimura Junji Urakawa 《Radiation Physics and Chemistry》2009,78(12):1106-1111
A near-relativistic 100-fs MeV electron beam is developed by using a photocathode rf gun for revealing the hidden ultrafast dynamics of intricate molecular and atomic processes in materials through experimentation of ultrafast time-resolved electron diffraction (UED). The transverse and longitudinal dynamics of femtosecond electron beam in the rf gun were studied theoretically by particle simulation. The growths of the emittance, bunch length and energy spread due to the rf and space charge effects were investigated by changing the laser parameters, field gradient and electron charge. The theoretical studies indicate that a 100-fs MeV electron beam with the transverse emittance of 0.1 mm mrad and the relative energy spread of 10−3–10−4 at bunch charge of 0.1–2 pC (106–107 electrons per pulse) is achievable for UED, in which the intensity is three orders of magnitude higher than that produced by the conventional dc or pulsed guns. 相似文献
102.
103.
A Strategy to Control the Reactivation of Frustrated Lewis Pairs from Shelf‐Stable Carbene Borane Complexes 下载免费PDF全文
Dr. Yoichi Hoshimoto Takuya Kinoshita Prof. Dr. Masato Ohashi Prof. Dr. Sensuke Ogoshi 《Angewandte Chemie (International ed. in English)》2015,54(40):11666-11671
N‐Phosphine oxide substituted imidazolylidenes (PoxIms) have been synthesized and fully characterized. These species can undergo significant changes to the spatial environment surrounding their carbene center through rotation of the phosphine oxide moiety. Either classical Lewis adducts (CLAs) or frustrated Lewis pairs (FLPs) are thus formed with B(C6F5)3 depending on the orientation of the phosphine oxide group. A strategy to reactivate FLPs from CLAs by exploiting molecular motions that are responsive to external stimuli has therefore been developed. The reactivation conditions were successfully controlled by tuning the strain in the PoxIm–B(C6F5)3 complexes so that reactivation only occurred above ambient temperature. 相似文献
104.
Yoichi Sakai Ryo Omatsuzawa Iwao Sakazaki Sayaka Suzuki Hayato Hashino Takanobu Saito Takahiko Iriyama 《Hyperfine Interactions》2005,166(1-4):483-487
Samarium–iron intermetallic compounds were prepared by a melt spinning method with low and high wheel speeds, which resulted in a Th2Zn17-type and a TbCu7-type structure, respectively. Structure comparison between these types was investigated for Sm–Fe intermetallic compounds and their nitrides by 57Fe-Mössbauer spectroscopy. 相似文献
105.
Nigel Ribeiro Denis Heissler Anne Marie Albrecht-Gary Mari Gotoh Yoichi Nakatani Guy Ourisson 《Tetrahedron》2007,63(16):3395-3407
Cholesterol plays the role of membrane reinforcer in eukaryotes, whereas hopanoids play the same role in bacteria. Which components could have reinforced ‘primitive’ membranes? We describe here an efficient biomimetic synthesis of bi- and tri-cyclopolyprenols and demonstrate that these compounds reinforce the membranes of polyprenyl phosphate, which we speculated as ‘primitive’ membranes. 相似文献
106.
107.
Norimichi Tsumura Daisuke Kawazoe Toshiya Nakaguchi Nobutoshi Ojima Yoichi Miyake 《Optical Review》2008,15(6):292-294
A simple regression-based model of skin diffuse reflectance is developed based on reflectance samples calculated by Monte
Carlo simulation of light transport in a two-layered skin model. This reflectance model includes the values of spectral reflectance
in the visible spectra for Japanese women. The modified Lambert Beer law holds in the proposed model with a modified mean
free path length in non-linear density space. The averaged RMS and maximum errors of the proposed model were 1.1 and 3.1%,
respectively, in the above range. 相似文献
108.
Reduction of [Ru2(CH3COO)2(C2O4)2(H2O)2]? by N-(2-hydroxyethyl)-ethylenediaminetriacetatoaquotitanium(III) [Ti(HEDTA)] involves several distinct stages. The first stage has a half-time of less than 1 ms, and is interpreted as a substitution reaction leading to a multinuclear intermediate. The second stage has a second-order rate constant of 5 x 103M?1s?1 [25°C, μ = 0.1 m (LiCF3SO3)]. The rate-limiting process for the second stage is electron transfer within the assembled multinuclear complex. Subsequent slower stages correspond to breakup of the multinuclear Ru(II)2-Ti(IV) complex formed by electron transfer. The overall rate of reduction of this oxidant by Ti(HEDTA) is less than the corresponding rate for the reaction in which Ti3+ acts as reductant, mainly because the stability of the binuclear complex is reduced by the presence of the aminoacid ligand. The data are consistent with the conclusion that the ligand increases the rate of intramolecular ET, probably by reducing geometric change associated with oxidation of Ti(III) to Ti(IV). 相似文献
109.
110.
Keiichiro Adachi Yumiko Hirose Yoichi Ishida 《Journal of Polymer Science.Polymer Physics》1975,13(8):1491-1499
The dielectric constant of solutions of poly(γ-benzyl-L -glutamate) (PBLG) in dichloromethane shows a jump near 195°K, irrespective of frequency. Therefore, the discontinuity is not a dispersion phenomenon but a phase transition in the thermodynamic sense. The transition temperature is independent of the concentration in the range from 0.01 to 10% by weight, but it increases linearly with the logarithm of the molecular weight of PBLG. The height of the jump depends strongly on frequency, concentration, and molecular weight. The viscosity also changes abruptly at 195°K. These results suggest that the PBLG molecule forms a cluster like a liquid crystal or is in a random coil state below the transition point. 相似文献