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131.
Masako Yamada Yoshihisa Iwashita Masahiro Ichikawa Takanori Sugimoto Hiromu Tongu Hiroshi Fujisawa Hirohiko M. Shimizu Takashi Ino Kenji Mishima Kaoru Taketani Tamaki Yoshioka Suguru Muto Takahiro Morishima Takayuki Oku Jun-ichi Suzuki Takenao Shinohara Kenji Sakai Hiromi Sato Katsuya Hirota Yoshie Otake Yoshichika Seki Shinsuke Kawasaki Sachio Komamiya Yoshio Kamiya Hidetoshi Otono Satoru Yamashita Peter Geltenbort 《Physica B: Condensed Matter》2009,404(17):2646-2651
Modulating permanent magnet sextupole lens (PMSx) for focusing pulsed cold neutrons is under development. The synchronized modulation of its field gradient suppresses the chromatic aberration which arises from the Time Of Flight method. The strength of the magnetic field, the torque, and the rise of temperature during its operation are studied on a fabricated prototype. Experiments on focusing pulsed very cold neutrons (VCN) at ILL (Institute of Laue Langevin, France) were carried out and VCN with around λ=40 Å were focused by the PMSx at a focal length of about 0.5 m. The experimental results are presented in conjunction with the principle of the neutron focusing and the modulating method of the focal strength of permanent magnet lens with the double ring structure. 相似文献
132.
Tomoya Miura Naoki Oku Masahiro Murakami 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14762-14766
We report the highly diastereo‐ and enantioselective preparation of (E)‐δ‐boryl‐substituted anti‐homoallylic alcohols in two steps from terminal alkynes. This method consists of a cobalt(II)‐catalyzed 1,1‐diboration reaction of terminal alkynes with B2pin2 and a palladium(I)‐mediated asymmetric allylation reaction of the resulting 1,1‐di(boryl)alk‐1‐enes with aldehydes in the presence of a chiral phosphoric acid. Propyne, which is produced as the byproduct during petroleum refining, could be used as the starting material to construct homoallylic alcohols that are otherwise difficult to synthesize with high stereocontrol. 相似文献
133.
134.
Naofumi Ohtsu Masaoki Oku Toetsu Shishido Kazuaki Wagatsuma 《Applied Surface Science》2007,253(21):8713-8717
Core-level XPS spectra for clean surfaces of Ni3Al, NiAl, and NiAl3 alloys were studied. The clean surfaces were obtained by fracturing in the ultra-high vacuum chamber. The positive chemical shifts of Ni 2p3/2 peak for NiAl and NiAl3 from Ni metal were 0.2 and 1.0 eV, respectively. The negative shift for Al 2p peak and the positive shift for Ni 3p peaks increased with the decreasing concentration of the corresponding elements. The peak position of the bulk plasmon loss peak for Al 2s peak shifted toward higher energy side, and further, the intensity ratio decreased with the decrease in aluminum concentration. Both the peak intensity ratios of Al 2p to Ni 3p determined by factor analysis and convenient separation are proportional to the atomic ratio of aluminum to nickel. The results indicate that the intensity ratio of Al 2p to Ni 3p determined by these two methods can be applied to the quantification for the surface of the nickel-aluminum alloys. 相似文献
135.
Naofumi Ohtsu Bun Tsuchiya Masaoki Oku Tatsuo Shikama Kazuaki Wagatsuma 《Applied Surface Science》2007,253(16):6844-6847
The initial oxidation of hafnium hydride was studied by X-ray photoelectron spectroscopy (XPS). The clean surface of hafnium hydride was obtained by fracturing the specimen in an XPS measurement chamber under a background pressure of 2.7 × 10−6 Pa. The fractured surface was oxidized in situ with the exposure to high-purity oxygen and the residual gases in an ultra-high vacuum chamber. The XPS spectra for the oxidized surfaces had the shoulder due to the oxidation, and the shoulder grew up with increase in exposure time even in the ultra-high vacuum. The factor analysis for the XPS spectra of the oxidized surface showed that the oxide formed in the chamber consists of only the hafnium dioxide, and no suboxide states are contained. The result corresponded to the oxide observed on hafnium hydride fractured in air. 相似文献
136.
Masaoki Oku Shigeru Suzuki Kenji Abiko Hiroshi Kimura Kichinosuke Hirokawa 《Journal of Electron Spectroscopy and Related Phenomena》1984,34(1):55-65
Auger and electron energy-loss spectroscopies (ELS) have been used to study chemical states at the fracture surfaces of iron-phosphorus alloys. The transgranular (TG) and intergranular (IG) fracture planes have similar Auger P LVV transition energies and similar Fe 3p loss energies. These indicate that phosphorus and iron atoms are dispersed atomically in layers segregated at IG planes. The energy separations between the inter-and intra-atomic Auger transition peaks in P LVV show that the TG and IG planes and Fe3P have similar energy separations between the P 3p and Fe 3p levels. The layers segregated at IG planes are estimated to be equivalent to a monolayer, as indicated by the dependence of the loss energy of the valence-conduction-band transition on primary-electron kinetic energy from 200 to 500 eV. The phosphorus concentration in the segregated layers is saturated to ~ 20 at.% above a bulk phosphorus concentration of 2 at.%. 相似文献
137.
138.
Masaoki Oku Shigeru Suzuki Kenji Abiko Hiroshi Kimura Kichinosuke Hirokawa 《Journal of Electron Spectroscopy and Related Phenomena》1981,23(2):147-156
A semi-quantitative method is proposed for determining the thickness of a covering layer on a solid. The thickness is calculated from the intensity ratios between Auger electron spectra (AES) and core-electron energy-loss spectra (ELS) for the uncovered and covered surfaces. This method needs no standard sample or ion sputtering to estimate the thickness, although it involves a number of assumptions. It has been applied to the determination of the thickness of segregated phosphorus layers on intergranular fracture planes of FeP alloys, using a cylindrical-mirror electron analyzer. 相似文献
139.
Incorporation of organic groups within the channel wall of spin-on mesostructured silica films by a vapor infiltration technique 总被引:1,自引:0,他引:1
Tanaka S Kaihara J Nishiyama N Oku Y Egashira Y Ueyamat K 《Langmuir : the ACS journal of surfaces and colloids》2004,20(9):3780-3784
Organically functionalized mesoporous silica films have been prepared by a novel synthetic procedure that involves spin-coating of mesostructured silica films and a vapor infiltration (VI) technique, using organosiloxanes, before the removal of surfactant. The VI-treated mesostructured films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and a field emission scanning electron microscope (FE-SEM). Nitrogen adsorption/desorption measurements were performed using films attached with a silicon substrate. The XRD and FE-SEM measurements show that the mesochannel wall, densified and modified with organosilyl groups by the VI treatment, hardly contracts under calcination. FE-SEM observations for the films' cross section support the view that organosiloxane vapor is not deposited on the surface of the film. These results show that organosiloxane molecules penetrate the film and are selectively incorporated into the silica wall. Thus, hydrophobic mesoporous silica films can be synthesized without a reduction in pore size, a result that cannot be attained by conventional grafting and co-condensation methods. The excellent high porosity and hydrophobicity of the mesostructured composite films may be of advantage for next-generation low-k dielectric films. 相似文献
140.
Wang X Adachi S Iwai H Takatsuki H Fujita K Kubo M Oku A Harada T 《The Journal of organic chemistry》2003,68(26):10046-10057
allo-Threonine-derived O-aroyl-B-phenyl-N-tosyl-1,3,2-oxazaborolidin-5-ones 1g,n catalyze the asymmetric Mukaiyama-Michael reaction of acyclic enones with a trimethylsilyl ketene S,O-acetal in high enantioselectivity. A range of alkenyl methyl ketones is successfully employed as Michael acceptors affording ee values of 85-90% by using 10 mol % of the catalyst. The use of 2,6-diisopropylphenol and tert-butyl methyl ether as additives is found to be essential to achieve high enantioselectivity in these reactions. The effects of the additives are discussed in terms of the retardation of an Si(+)-catalyzed racemic pathway, which seriously deteriorates the enantioselectivity of asymmetric Mukaiyama-Michael reactions. A working model for asymmetric induction is proposed based on correlation between catalyst structures and enantioselectivities. 相似文献