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211.
Toru Asahi Yuko Egawa Atsushi Sugiyama Takanori Kiya Kazuhiro Ouchi 《Journal of magnetism and magnetic materials》2010,322(23):3784-3788
SmCo5 alloy is a promising candidate for ultra-high-density perpendicular magnetic recording (PMR) media because of its high uniaxial magnetocrystalline anisotropy Ku of more than 1.1×108 erg/cm3. Previously, we successfully achieved high Ku in a sputter-deposited SmCo5 thin film by introducing a Cu/Ti dual underlayer. However, in order to apply the SmCo5 films to practical PMR media, it is necessary to decrease medium noise. A granulated magnetic film comprising of small and magnetically decoupled grains is effective in reducing the medium noise. In this paper, we have proposed a new granular film that is fabricated by partial thermodiffusion of Cu between the Sm-Co continuous layer and the Cu underlayer, which is granulated using compositional segregation caused by the addition of Ta2O5. We have analyzed the magnetic properties, magnetic domain size, and magnetization reversal process of the proposed SmCo5 film. The magnetic domain size decreased and the magnetization reversal process changed from the magnetic-wall-motion mode to a coherent rotation mode to some extent on isolation of magnetic grains. The read/write characteristics of granulated SmCo5 double-layered media were also evaluated. The medium noise decreased and the signal-to-noise ratio increased for the granulated double-layered (PMR) medium. 相似文献
212.
M. Yoshida K. Ishii K. Ikeuchi I. Jarrige Y. Murakami J. Mizuki K. Tsutsui T. Tohyama S. Maekawa K. Kudo Y. Koike Y. Endoh 《Physica C: Superconductivity and its Applications》2010
We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the two-leg ladder Sr14Cu24O41. RIXS spectra at 1–5 eV are found to be dependent on temperature. An intraband excitation of the ladder, which appears as a continuum intensity below the Mott gap, decreases in intensity with temperature. Because the intraband excitation is related to the dynamics of doped holes in the ladder, its decrease of the intraband excitation is attributed to the reduction of the mobile holes in the ladder at low temperature. 相似文献
213.
Ayumi Takizawa Eriko Doi Akio Murai Hidetoshi Kawai Takanori Suzuki 《Tetrahedron》2006,62(31):7408-7435
Convergent synthesis of the common FGHI-ring part (54) of ciguatoxins was achieved via the following key steps: (i) the Nozaki-Hiyama-Kishi reaction connecting the F-ring part (6) with the I-ring part (7); (ii) regio- and stereoselective epoxidation; (iii) the 6-exo-epoxide opening reaction forming simultaneously the H-ring and the quaternary asymmetric center at C30; (iv) inversion of the C29 stereocenter by a two-step oxidation/reduction process, where the successful inversion depended on proper management of the steric environment of the substrate; and (v) final reductive cyclization constructing the G-ring. 相似文献
214.
Akai N Harada T Shin-Ya K Ohno K Aida M 《The journal of physical chemistry. A》2006,110(18):6016-6022
The photoreaction of 2-amino-5-methylpyridine was investigated by matrix-isolation infrared spectroscopy and DFT calculation. Photoinduced reversible amino (N=C-NH(2))-imino (NH-C=NH) tautomerism was found between 2-amino-5-methylpyridine and 5-methyl-2(1H)-pyridinimine; the amino tautomer changes to the imino tautomer by UV irradiation (340>lambda>or= 300 nm) and the reverse change occurs by longer-wavelength light irradiation (420>lambda>or= 340 nm). The results of the CASSCF calculation revealed that the amino-imino tautomerism proceeds in vibrational relaxation process from electronic excited state to the ground state. The IR spectra of 2-amino-5-methylpyridine in the T(1) state and 5-methyl-2-pyridinamino radical were also obtained by UV irradiation (lambda>or= 300 nm). 相似文献
215.
The tetranuclear zinc cluster Zn4(OCOCF3)6O catalyzes the direct conversion of esters, lactones, and carboxylic acids to oxazolines with remarkable chemoselectivity. 相似文献
216.
We have developed new chiral Schiff base catalysts for the enantioselective addition of diethylzinc reagents to aldehydes. The reaction of benzaldehyde with diethylzinc in the presence of 1 mol % of the chiral Schiff base catalyst proceeded to afford 1-phenyl-1-propanol in 96% enantiomeric excess (ee). 相似文献
217.
Murakami R Sakamoto H Hayami Y Matsubara H Takiue T Aratono M 《Journal of colloid and interface science》2006,295(1):209-217
The adsorption behavior and the phase transition of alkanol and fluoroalkanol at the electrified mercury/aqueous solution interface were investigated by the interfacial tension measurements and the thermodynamic analysis. In the alkanol system, it is found that the phase transitions in low interfacial densities occur: the ones from the zero adsorption to the gaseous or the expanded state and the gaseous to the expanded state at the electrified interface depending on the electrostatic nature as well as the concentration in the bulk phase. These phase transitions were verified by the thermodynamic equations derived by the assumption of coexistence of two phases at the electrified interface. Furthermore the distribution of ionic species in the interfacial region is discussed on the basis of dependence of the interfacial charge density of solution phase on an applied potential. Fluoroalkanol, on the other hand, was practically not adsorbed at the electrified interface within this experimental condition. The zero adsorption of fluoroalkanol molecules suggests the driving force of the adsorption may be the interaction hydrophobic group of alcohol molecule and mercury. 相似文献
218.
Takahashi H Hossain KM Nishihara Y Shibata T Takagi K 《The Journal of organic chemistry》2006,71(2):671-675
[reaction: see text] The catalytic activity of a Rh complex in cross-coupling between ArZnI and TMSCH2I was examined in which the Rh complex, generated in situ from [RhCl(1,5-cyclooctadiene)]2 and 1,1'-bis(diphenylphosphino)ferrocene, exhibited excellent catalytic activity for the production of various functionalized benzylsilanes in good yields. From 31P NMR studies of various solutions containing several of the reaction components, confirmation of the rapid and quantitative transfer of aryl groups from ArZnI to the Rh complex to form arylrhodium species was ascertained. A catalytic cycle, commencing with the transmetalation, was thus proposed for the reaction. 相似文献
219.
Wang L Shima T Hampel F Gladysz JA 《Chemical communications (Cambridge, England)》2006,(39):4075-4077
trans-Rh(CO)(Cl)(P((CH(2))(14))(3)P) is prepared from trans-Rh(CO)(Cl)(P((CH(2))(6)CH[double bond, length as m-dash]CH(2))(3))(2) by a metathesis/hydrogenation sequence, and converted by substitution or addition reactions to Rh(CO)(I), Rh(CO)(2)(I), Rh(CO)(NCS), and Rh(CO)(Cl)(Br)(CCl(3)) species; the Rh(CO)(Cl) and Rh(CO)(I) moieties rapidly rotate within the cage-like diphosphine, but the other rhodium moieties do not. 相似文献
220.
The reaction of the tetranuclear rare earth metal polyhydrido complexes {Cp'Ln(mu-H)2}4(THF) (Cp' = C5Me4SiMe3, Ln = Y (1a), Lu (1b)) with carbon monoxide (1 atm) yielded ethylene and the corresponding tetraoxo cubane complexes (Cp'Ln)4(mu3-O)4 (Ln = Y (5a), Lu (5b)). Stepwise formation of some key reaction intermediates, such as oxymethylene complexes (Cp'Ln)4(mu-OCH2)(mu-H)6(THF) (Ln = Y (2a), Lu (2b)), enolate species (Cp'Y)4(OCH=CH2)(mu-O)(mu-H)5(THF) (3), and dioxo complex (Cp'Y)4(mu3-O)2(mu-H)4(THF) (4), was confirmed. The molecular structures of 2a, 4, and 5b were determined by X-ray diffraction studies. 相似文献