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111.
Noriko Nakagawa Takafumi Yamada Koji Akioka Susumu Okubo Shojiro Kimura Hitoshi Ohta 《International Journal of Infrared and Millimeter Waves》1998,19(2):167-176
New systems for millimeter and submillimeter wave ESR have been developed in Kobe University. In the previous system the pulsed magnetic field was limited up to 17 T in the temperature range from 1.8 to 86 K. Using the new systems, we can measure in the field range up to 30 T in the temperature range from 1.8 K to 4.2 K and from 18 K to room temperature. The resolution of the magnetic field has been also improved in the new ESR system. The details of our new ESR systems are presented. In addition, the measurements of Yb2Cu2O5 using these new systems are presented. 相似文献
112.
Yasunori Fujikoshi Takafumi Noguchi Megu Ohtaki Hirokazu Yanagihara 《Annals of the Institute of Statistical Mathematics》2003,55(3):537-553
This paper is concerned with cross-validation (CV) criteria for choice of models, which can be regarded as approximately unbiased
estimators for two types of risk functions. One is AIC type of risk or equivalently the expected Kullback-Leibler distance
between the distributions of observations under a candidate model and the true model. The other is based on the expected mean
squared error of prediction. In this paper we study asymptotic properties of CV criteria for selecting multivariate regression
models and growth curve models under the assumption that a candidate model includes the true model. Based on the results,
we propose their corrected versions which are more nearly unbiased for their risks. Through numerical experiments, some tendency
of the CV criteria will be also pointed. 相似文献
113.
A laser ablation-inductively coupled plasma-mass spectrometric (LA-ICPMS) technique utilizing a titanium-sapphire (TiS) femtosecond laser (fs-laser) has been developed for elemental and isotopic analysis. The signal intensity profile, depth of the ablation pit and level of elemental fractionation were investigated in order to evaluate the analytical capability of the present fs-laser ablation-ICPMS technique. The signal intensity profile of (57)Fe, obtained from iron sulfide (FeS(2)), demonstrated that the resulting signal intensity of (57)Fe achieved by the fs-laser ablation was almost 4-times higher than that obtained by ArF excimer laser ablation under a similar energy fluence (5 J/cm(2)). In fs-laser ablation, there is no significant difference in a depth of the ablation pit between glass and zircon material, while in ArF laser ablation, the resulting crater depth on the zircon crystal was almost half the level than that obtained for glass material. Both the thermal-induced and particle size-related elemental fractionations, which have been thought to be main sources of analytical error in the LA-ICPMS analysis, were measured on a Harvard 91500 zircon crystal. The resulting fractionation indexes on the (206)Pb/(238)U (f(Pb/U)) and (238)U/(232)Th (f(U/Th)) ratios obtained by the present fs-laser ablation system were significantly smaller than those obtained by a conventional ArF excimer laser ablation system, demonstrative of smaller elemental fractionation. Using the present fs-laser ablation technique, the time profile of the signal intensity of (56)Fe and the isotopic ratios ((57)Fe/(54)Fe and (56)Fe/(54)Fe) have been measured on a natural pyrite (FeS(2)) sample. Repeatability in signal intensity of (56)Fe achieved by the fs-laser ablation system was significantly better than that obtained by ArF excimer laser ablation. Moreover, the resulting precision in (57)Fe/(54)Fe and (56)Fe/(54)Fe ratio measurements could be improved by the fs-laser ablation system. The data obtained here clearly demonstrate that, even with the fundamental wavelength (NIR operating at 780 nm), the fs-laser ablation system has the potential to become a significant tool for in-situ elemental and isotopic analysis of geochemical samples including heavy minerals and metallic materials. 相似文献
114.
115.
[reaction: see text] The first catalytic asymmetric synthesis of 2-aryl-2,3-dihydro-4-quinolones has been developed by way of a rhodium-catalyzed 1,4-addition of arylzinc reagents to 4-quinolones. These 1,4-adducts can be obtained with high enantioselectivity by the use of (R)-binap as a ligand, and high yields are realized by conducting the reactions in the presence of chlorotrimethylsilane. 相似文献
116.
J. Wang M. Takahashi T. Kitazawa M. Takeda 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(1):195-199
155Gd Mössbauer spectra of some Gd(III)-b-diketonato complexes are reported. All of their 155Gd Mössbauer isomer shift (d) values fall in a narrow range of +0.55-+0.65 mm.s-1, and are between those of GdF3 and the cubic form of Gd2O3. This indicates that their Gd-O bonds have small covalent character. The value for quadrupole coupling constant (e2qQ) spread out from 1.67 to 7.56 mm.s-1 and reflects the difference well in symmetry of the coordination polyhedron around Gd(III) ions for those Gd(III)-b-diketonato complexes. 相似文献
117.
Takafumi Uematsu Shinya Maenosono Akira Watanabe Yukio Yamaguchi 《Journal of Polymer Science.Polymer Physics》2002,40(2):216-225
We report on a self‐organized striped pattern of refractive indices in a photopolymer and the resulting angular dependence in the transmittance as a result of the microstructure. The photopolymer plates were obtained by photoreaction of a monomer mixture placed in a space between two glass plates. The monomer mixture was prepared by mixing bifunctional methacrylate monomer, cyanoethylmethacrylate, and 2,4,6‐trimethylbenzoyldiphenylphosphine oxide as photoinitiator. After the photoreaction by uniform irradiation of UV light, the self‐organized striped pattern was observed in the crosslinked photopolymer plate by optical microscopy. Electron probe microanalysis of the cross section of the polymer plate confirms that a compositional inhomogeneity in the medium is quite small. The result suggests that the optically observed striped pattern is not due to the compositional and/or density modulation through the diffusion of monomers. We attribute the striped pattern to the crosslink density modulation and the resulting refractive‐index modulation. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 216–225, 2002 相似文献
118.
119.
Chiral calixarene analogs incorporating cystine peptide into their macrocyclic ring were easily prepared by the cyclization reactions of bis(chloromethyl)phenol-formaldehyde oligomers with cystine peptides in moderate yields. Circular dichroism (CD) spectra indicated the existence of the transmission of the chirality from peptide unit to phenol-formaldehyde oligomer moiety. 相似文献
120.
Yoshitane Imai Takafumi Kinuta Nobuo Tajima Yoshio Matubara 《Tetrahedron letters》2006,47(21):3603-3606
By using three types of viologen derivatives, we synthesized chiral charge-transfer (CT) complexes with an axially chiral 1,1′-bi-2-naphthol molecule and successfully controlled the crystal structure and inclusion ability of the third component by changing the viologens. 相似文献