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51.
Asano T Nojiri H Inagaki Y Boucher JP Sakon T Ajiro Y Motokawa M 《Physical review letters》2000,84(25):5880-5883
A "breather excitation" is observed directly by electron spin resonance in the quantum spin chain Cu benzoate, in which an unexpected field-induced gap has recently been found. The nonlinear field dependence of the resonance field agrees well with the formula based on a quantum sine-Gordon model. The power-law temperature dependence of the linewidth is observed in the gapless spinon regime while the width decreases exponentially for the gapped breather regime. In the intermediate range, a distinct anomaly is found, which is the manifestation of "the spinon-breather dynamical crossover." 相似文献
52.
Hiroyuki Uesaka Chooichiro Asano 《Annals of the Institute of Statistical Mathematics》1987,39(1):513-531
Summary The purpose of the present paper is to propose an analytical method for ordered categorical responses obtained from a repeated
measurement/longitudinal experiment. The ordered categorical scale is assumed to be a manifestation of a latent quantitative
variable. A linear model is assumed for location parameters of the underlying distributions. Weighted least square method
is applied to parameter estimation and subsequent analysis. Two data sets are analyzed to show several aspects of analysis
by the proposed model and to discuss comparative characteristics of analysis compared with earlier analysis. A mention is
made for a computer software program for the proposed model. 相似文献
53.
Overtone spectrum of o, m and p-nitrobenzaldehydes and p-chlorobenzaldehyde has been studied in 2000–12000 cm−1 region. Vibrational frequencies and anharmonicity constants for aryl as well as alkyl CH stretch vibrations have been determined.
We have also determined the internuclear distances for the aryl CH bond in the different molecules. The small variation observed
in these distances is an indication of the substitution effect.
It is observed that in the case of p-disubstituted benzens, the shift in aryl CH bond is proportional to sum of the Hammet σ of the substituents. However in the
case of o-disubstituted benzenes it is only 80% of the para-substituted shift. 相似文献
54.
Naoki Fujita Takayuki Makino Yasuhiro Sakoishi Katsuya Asano Masanobu Kusunoki 《Crystal Research and Technology》2016,51(3):215-219
The relation between O2 pressure and composition in the pulsed‐laser deposition of fluoroapatite was investigated using both on‐axis and off‐axis methods to determine the optimal conditions for obtaining a pure fluoroapatite film without OH groups. Through this, it was found that an O2 pressure of 10 Pa, combined with an off‐axis method, results in P/Ca and F/Ca values (0.6 and 0.2, respectively) that match closely with a stoichiometric composition of Ca10(PO4)6F2. Fourier transform infrared spectroscopy analysis confirmed that this optimized film was almost pure fluoroapatite, with no evidence of any OH groups originating from hydroxyapatite. X‐ray diffraction also revealed that this fluoroapatite film crystallizes with a c‐axis orientation perpendicular to its surface. 相似文献
55.
Michael Andreas Tandiary Masashi Asano Taiki Hattori Satoshi Takehira Yoichi Masui Makoto Onaka 《Tetrahedron letters》2017,58(20):1925-1928
The solid acid, tin hydroxide-embedded montmorillonite, catalyzes the unprecedented alkylation of various silicon enolates with primary, secondary and tertiary benzylic alcohols as well as secondary allylic alcohols. The acid catalysis of Sn-Mont was not only higher than that of the other ion-exchanged montmorillonites (M-Mont; M = H, Ti, Fe and Al), but also higher than that of the typical homogeneous acid catalysts such as BF3·OEt2, TMSOTf and TfOH. 相似文献
56.
In the thermochemical water-splitting iodine–sulfur process for hydrogen production, new polymer electrolyte membranes were applied in an electro-membrane process (electro-electrodialysis, EED) to increase the HI molality of HIx solution (HI + I2 + H2O mixture) to be over quasi-azeotropic. Radiation grafting of a styrene monomer into a poly(ethylene-co-tetrafluoroethylene) base film and subsequent sulfonation provided electrolyte membranes that had ion exchange capacities (IECs) of 1.1–1.6 mmol/g. With the EED of the HIx solutions using [HI] = [I2] = 10 mol/kg at 40 °C the transport number of protons, ratio of permeated quantities of water to the protons, and current efficiency all appeared to depend on the IEC of the resulting membranes. When compared to Nafion, the self-made membranes exhibited lower electric cell resistance, and thereby decreasing up to 32% of the overall energy required in the concentration operation. 相似文献
57.
Sasakura H Kuramitsu S Hayashi Y Tanaka K Akazaki T Hanamura E Inoue R Takayanagi H Asano Y Hermannstädter C Kumano H Suemune I 《Physical review letters》2011,107(15):157403
We experimentally demonstrate Cooper pairs' drastic enhancement of the band-to-band radiative recombination rate in a semiconductor. Electron Cooper pairs injected from a superconducting electrode into an active layer by the proximity effect recombine with holes injected from a p-type electrode. The recombination of a Cooper pair with p-type carriers dramatically increases the photon generation probability of a light-emitting diode in the optical-fiber communication band. The measured radiative decay time rapidly decreases with decreasing temperature below the superconducting transition temperature of the niobium electrodes. Our results indicate the possibility to open up new interdisciplinary fields between superconductivity and optoelectronics. 相似文献
58.
59.
K. Ogura T. Hattori M. Asano M. Yoshida H. Omichi N. Nagaoka H. Kubota R. Katakai H. Hasegawa 《Radiation measurements》1997,28(1-6):197-200
We studied the track response for the copolymer of CR-39 monomer with N-isopropylacrylamide (NIPAAm) as well as etching properties. It was found that copoly (CR-39/NIPAAm/Naugard 445) composed in wieght ratio of 99/1/0.01 is highly sensitive to low LET particles in the region below 10 keV/μm of LET
and able to record normally incident particles of LET
down to 1.5 keV/μm, recording protons up to the energy of 27 MeV. These results were compared with the responses for two types of CR-39 detectors containing a small quantity of antioxidant. The threshold energy proton registration is discussed. 相似文献
60.
On the basis of a hypothesis that cyclization and alkylation of the diamine part in formula 1 may give highly active compounds, a new series of 5-isoquinolinesulfonamide derivatives, shown as formula 2, were prepared from cyclic diamines. Their vasodilatory effects were subsequently evaluated in vivo according to the increase in arterial blood flow after the formulas were injected locally to the femoral and/or vertebral arteries of dogs. Cyclization of the diamine structure in formula 1 gave very potent vasodilators: 6 and 14. Acylation and sulfonylation of terminal amino nitrogen afforded much less potent compounds. In contrast to the hypothesis, alkylation on the ring carbon and the terminal nitrogen of the cyclic amine afforded less active compounds except for compound 11. The most active compounds, 6, 11 and 14, showed more potent vasodilatory effects and more selective activity to the vertebral artery than either trapidil or diltiazem. 相似文献