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991.
We present a systematic characterization of fluctuations in submicron Hall devices based on GaAs/AlGaAs two-dimensional electron gas heterostructures at temperatures between 1.5 to 60 K. A large variety of noise spectra, from 1/f to Lorentzian, are obtained by gating the Hall devices. The noise level can be reduced by up to several orders of magnitude with a moderate gate voltage of 0.2 V, whereas the carrier density increases less than 60% in the same range. The significant dependence of the Hall noise spectra on temperature and gate voltage is explained in terms of the switching processes related to impurities in n-AlGaAs. 相似文献
992.
The direct addition of a proton to a carbonyl oxygen in an eta2-enone complex of palladium and platinum led to the quantitative formation of eta3-1-hydroxyallyl complexes of palladium and platinum, of which X-ray diffraction analysis showed typical eta3-allyl structure. 相似文献
993.
α-Fluoro-α-silyl-substituted sulfones 1 are readily prepared from fluoromethyl phenyl sulfone and the appropriate silyl chloride. The use of TBSCl improves both the stability and yield of 1. Lithium derivatives 4 undergo a smooth Peterson olefination reaction with less-enolizable carbonyl compounds to give moderate to good yields of the expected α-fluorovinylsulfones 6, in some cases with high E-stereoselectivity. One-pot reaction with 4 generated in situ from fluoromethyl phenyl sulfone in tetrahydrofuran (THF) also proceeds smoothly, particularly with aldehydes. 相似文献
994.
Arai N Shiomi K Yamaguchi Y Masuma R Iwai Y Turberg A Kölbl H Omura S 《Chemical & pharmaceutical bulletin》2000,48(10):1442-1446
A new chitinase inhibitor, designated as argadin (1), was isolated from the cultured broth of a fungal strain FO-7314. The strain was identified as Clonostachys sp. from the morphological characteristics. Argadin was purified from the cultured mycelium by a combination of cation exchange, adsorption and gel filtration chromatographic methods. The structure of argadin was elucidated as cyclo(Nomega-acetyl-L-arginyl-D-prolyl-homoseryl-histidyl-L- 2-aminoadipyl) in which homoseryl gamma-methylene bonded to histidyl alpha-amino residue. The IC50 value of argadin against Lucilia cuprina (blowfly) chitinase was 150 nM at 37 degrees C and 3.4 nM at 20 degrees C. Argadin arrested the moult of cockroach larvae upon injection into the ventral abdominal part. 相似文献
995.
Hideo Ikeda 《Journal of Dynamics and Differential Equations》1993,5(4):625-671
The multiple existences and their stability properties of stationary solutions with a single transition layer in some scalar reaction-diffusion equation are shown. Each solution is constructed by using classical singular perturbation methods and its stability property is determined by a simple algebraic quantity, say index, appearing in the construction of a solution. 相似文献
996.
A two-dimensional numerical simulation of natural convection in a rectangular enclosure heated from below and cooled from
above has been conducted with non-Newtonian phase-change-material (PCM) microcapsulate slurry with latent heat capacities.
The formulation of the mathematical model in dimensionless co-ordinates and discretization of the governing equations have
been done using the finite volume method. Both natural convection and heat transfer characteristics are discussed about natural
convection with PCM microcapsulate slurry, which exhibits the pseudoplastic non-Newtonian fluid behavior and a peak value
in the specific heat capacity with latent heat. The viscosity of the present PCM microcapsulate slurry is assumed to follow
the Ostwald-de Waele power law fluid model with the power-law index n and the consistency coefficient K. The effects of phase-change material, the mass concentration, and the aspect ratio Ar on the natural convection heat transfer
are described, respectively. By comparing with the results of microcapsule slurry without phase change, the enhancement in
heat transfer is found in microcapsule slurry with phase change during the phase change temperature range. Numerical simulations
are performed in the following parametric ranges: the width–height aspect ratio of the enclosure Ar from 2 to 20, the mass
concentrations C
m of the slurry from 10 to 40%, power law index n of the slurry from 0.89 to 1.0 and Rayleigh numbers Ra ranges from 103 to 107. 相似文献
997.
Ichihara Mai Inoue Kazumasa Fukushi Masahiro Shimizu Hideo Tsuruoka Hiroshi Veerasamy Nimelan Tsukada Mizuho Soyama Sho Hosokawa Shota Kato Tatsuki Sagara Hiroaki Taguchi Yoshiaki Natarajan Thennaarassan 《Journal of Radioanalytical and Nuclear Chemistry》2021,329(1):427-435
Journal of Radioanalytical and Nuclear Chemistry - Tokatsu area was on one pathway of the radioactive plumes released in the Fukushima Daiichi Nuclear Power Plant accident and absorbed dose rate in... 相似文献
998.
Dr. Kunihiko Okano Dr. Satoshi Aya Dr. Fumito Araoka Haruki Obara Shiori Sato Prof. Dr. Takashi Yamashita Prof. Dr. Hideo Takezoe Prof. Dr. Kouichi Asakura 《Chemphyschem》2015,16(1):95-98
A periodic stripe pattern is found in the nematic phase close to the smectic phase of photoresponsive achiral liquid‐crystalline compounds. The origin of the stripe patterns can be ascribed to an extremely large bent elastic constant K33. In addition, we succeeded in controlling the pattern by the following two methods: 1) the stripe disappears by a trans–cis photoisomerization upon UV light irradiation and reappears upon light termination, and 2) the stripe pattern is stabilized over the whole nematic phase, at approximately 10 °C, by polymerization of the compounds. 相似文献
999.
Takasaki M Motoyama Y Yoon SH Mochida I Nagashima H 《The Journal of organic chemistry》2007,72(26):10291-10293
Use of Ru/CNF-P, nanoruthenium particles dispersed on a nanocarbon fiber support, realizes highly efficient catalytic partial hydrogenation of 1,1'-bi-2-naphthol and -naphthyl-amine derivatives. The reactions proceed in high turnover numbers without racemization of the axial chirality, offering a practical procedure for the production of optically pure 5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyls in good to high yields. 相似文献
1000.
An intramolecular Friedel-Crafts reaction of N-methoxymethyl sulfoneamides 3e-j containing an acetylene dicobalt moiety was found to proceed smoothly to afford eight- and nine-membered cyclic amines 4e-j in high yields. 相似文献