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51.
Takashi Komine Kota Takahashi Hiroshi Murakami Ryuji Sugita 《Journal of magnetism and magnetic materials》2010,322(19):2969-2972
In this study, the effect of exchange stiffness constant on current-driven domain wall motion in nanowires with in-plane magnetic anisotropy (IMA) and perpendicular magnetic anisotropy (PMA) has been investigated using micromagnetic simulation. The critical current density in a nanowire with IMA decreases as the exchange stiffness constant decreases because the domain wall width at the upper edge of the nanowire narrows according to the decrease of the exchange stiffness constant. On the other hand, the critical current density in a nanowire with PMA slightly decreases contrary to that of IMA although the domain wall width reasonably decreases as the exchange stiffness constant decreases. The slight reduction rate of the critical current density is due to the increase of the effective hard-axis anisotropy of PMA nanowire. 相似文献
52.
Alternating-current (ac) magnetic susceptibility measurements for tris(dipicolinato) complexes with a trivalent heavy lanthanide ion, [N(C2H5)4]3[Ln(dipic)(3)] x nH2O (dipic = pyridine-2,6-dicarboxylate; Ln = Tb, Dy, Ho, Er, Tm, or Yb) are reported. While none of the six complexes showed a magnetization lag from the ac magnetic field of 10-10(3) Hz above 1.8 K, the Dy, Er, and Yb complexes with odd numbers of 4f electrons exhibited the magnetization lag in a static magnetic field. This phenomenon is explained to be caused by the elimination of a fast relaxation path, which is only effective for the Kramers doublet ground states in near zero field. At higher static fields, the remaining paths such as Orbach and/or direct processes govern the dynamics of the two-level systems comprised of spin-up and spin-down states. The non-Kramers complexes were found to have a nondegenerate ground state with large energy gaps from higher states, which is consistent with their fast magnetization relaxation. 相似文献
53.
54.
Oku K Kurose M Kubota M Fukuda S Kurimoto M Tujisaka Y Okabe A Sakurai M 《The journal of physical chemistry. B》2005,109(7):3032-3040
In a previous study (Oku, K.; Watanabe, H.; Kubota, M.; Fukuda, S.; Kurimoto, M.; Tujisaka, Y.; Komori, M.; Inoue, Y.; Sakurai, M. J. Am. Chem. Soc. 2003, 125, 12739), we investigated the mechanism of the antioxidant function of trehalose against unsaturated fatty acids (UFAs) and revealed that the key factor relevant to the function is the formation of OH...pi and CH...O hydrogen bonds between trehalose and the cis double bonds of the UFA. Here, we investigate whether such intriguing interactions also occur between this sugar and cis double bonds in other unsaturated compounds. For this purpose, we selected various diene compounds (1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, and 2,5-heptadiene) as interaction partners. All NMR experiments performed, including 1H-1H NOESY measurements, indicated that trehalose selectively interacts with the cis-olefin proton pair in the above diene with a 1:1 stoichiometry, and the C-3 (C-3') and C-6' (C-6) sites of the sugar are responsible for the interaction. Similar interactions were not observed for the mixtures of the diene and other saccharides (neotrehalose, kojibiose, nigerose, maltose, isomaltose, sucrose, maltitol, and sorbitol). Quantum chemical calculations revealed that the OH-3 and OH-6 groups bind to the olefin double bonds of the diene through OH...pi and CH...O types of hydrogen bonds, respectively, and the stabilization energy of the resulting complex is 5-6 kcal mol(-1). These results strongly support the above NMR results. Finally, the activation energies were calculated for the hydrogen abstraction reactions from the activated methylene group of heptadiene. In particular, when the reaction was initiated by a methyl radical, the activation energy was only 10 kcal mol(-1) for the free heptadiene, but on complexation with trehalose it drastically increased to ca. 40 kcal mol(-1). This indicates that trehalose has a significant depression effect on the oxidation of the diene compounds. These results strongly support the antioxidant mechanism deduced in the previous study and indicate that the formation of unique multiple hydrogen bonds between trehalose and cis-olefin bonds is rather a general event not confined to the case of UFA. 相似文献
55.
Kiyotaka Koyama Masahiro Ishino Takashi Sugita Kunio Takahashi 《Tetrahedron letters》2004,45(37):6947-6948
Phomactin H (1), a diterpene has been isolated from cultures of an unidentified marine-derived fungus. The structure and relative stereochemistry of phomactin H (1) was determined by X-ray diffraction analysis. Phomactin H (1), having an oxepane moiety, is a new phomactin with a novel skeleton. 相似文献
56.
Kageyama G Kawano S Kanagawa S Kondo S Sugita M Nakanishi T Shimizu A Kumagai S 《Rapid communications in mass spectrometry : RCM》2004,18(9):995-1000
A novel allele of transporters associated with the antigen-processing (TAP) 2 gene, TAP2*Bky2 (Val(577)), is significantly increased in Japanese patients with Sj?gren's syndrome (SS), and has a strong association with SS-A/Ro autoantibody production in SS and autoantibody including anti-SS-A/Ro and anti-U1 RNP antibody in systemic lupus erythematosus (SLE). To determine the influence of this natural mutated TAP on peptides loaded onto MHC class I, we analyzed the repertoire of peptides loaded onto MHC class I on transfectants with TAP1 and TAP2 or mutated TAP2 by electrospray ionization tandem mass spectrometry (ESI-MS/MS). After comparison of the peptide profiles we identified three peptides from only mutated TAP transfectants. Moreover, one of these peptides is derived from snRNP A, which is a target for anti-U1 RNP antibody. To our knowledge this is the first report to show that the natural mutation of TAP2 changes the peptide profile loaded onto MHC class I molecules. 相似文献
57.
Two kinds of glycosphingolipid analogues from the earthworm Pheretima hilgendorfi were synthesized as follows: the trisaccharide 2-(tetradecyl)hexadecyl alpha-D-mannopyranosyl-(1-->4)-beta-D-galactopyranosyl-(1-->6)-beta-D- galactopyranoside (13) and the tetrasaccharide 2-(tetradecyl) hexadecyl alpha-D-galactopyranosyl-(1-->6)-[alpha-D-mannopyranosyl-(1-->4)]-beta-D - galactopyranosyl-(1-->6)-beta-D-galactopyranoside (20) were synthesized by stepwise condensation of suitably protected monosaccharide units. A 2-(trimethylsilyl)ethyl 2,3,4-tri-O-benzoyl-beta-D-galactopyranoside derivative (5) was used as the glycosyl acceptor and thiophenyl derivatives of D-galactose and D-mannose were used as donors respectively. 相似文献
58.
Akio Sugita Katsuhide Onose Yasuji Ohmori Mitsuho Yasu 《Fiber and Integrated Optics》1993,12(4):347-354
To enable alignmentfree optical fiber coupling to single-mode silica-based waveguides, fiber-guiding grooves are fabricated in the same substrate as waveguide circuits.These grooves are used successfully to couple optical fiber to Waveguides. An average, fiber-to-waveguide coupling loss of 0.6 dB per interface is obtained with eight arrayedguiding grooves, and it is expected that this will further be reduced to 0.2 dB per interface. The coupling loss varies by ±0.3 dB during thermal cycling between -10°C and +60°C. 相似文献
59.
T. Nakayama H. Fukuda T. Kamikawa A. Sugita M. Kawasaki I. Morino G. Inoue 《Applied physics. B, Lasers and optics》2007,88(1):137-140
The absorption spectra of the 3ν3 band of nitrous oxide isotopologues, 14N15N16O and 15N14N16O, have been measured using diode laser cavity ring-down spectroscopy in 6400–6463 and 6465–6532 cm-1, respectively. Spectroscopic parameters and the rotational line intensities of the bands have been determined. We have applied
this spectroscopic technique to the measurements of the absolute isotope ratio of those isotopologues using the absolute line
intensities.
PACS 32.10.Bi; 33.20.Vq; 33.70.-w; 42.55.Px; 42.62.Fi 相似文献
60.
Quasi-phase-matched (QPM) UV second-harmonic generation (SHG) in a periodically poled MgO:LiNbO3 waveguide is presented. A ridge-type waveguide with high nonlinearity and strong resistance to photorefractive damage was achieved by use of an ultraprecision machining technique. By use of this waveguide in 1.4-microm periodically poled MgO:LiNbO3, a first-order QPM SHG device for 340-nm UV radiation was demonstrated. In a single-pass configuration, continuous-wave 22.4-mW UV light was generated for a fundamental power of 81 mW, corresponding to a normalized conversion efficiency of 340%/W. 相似文献