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排序方式: 共有197条查询结果,搜索用时 31 毫秒
21.
Aoyagi Y Saitoh Y Ueno T Horiguchi M Takeya K Williams RM 《The Journal of organic chemistry》2003,68(18):6899-6904
Lipase TL-mediated kinetic resolution of (+/-)-5-benzyloxy-1-tert-butyldimethylsilyloxy-2-pentanol (5) at low temperature proceeded to give the corresponding (S)-alcohol 5 and (R)-acetate 6 in quantitative yields with high enantiomeric purity. The addition of bases such as pyridine, DMAP, 2,4- and 2,6-lutidines, or triethylamine considerably enhanced the rate of kinetic resolution. The alcohol (S)-5 and the acetate (R)-6 were converted to piperazic acid derivatives (R)- and (S)-3, respectively, via the intramolecular Mitsunobu reaction as a key step. 相似文献
22.
Masaaki Shiono Naohiro Matsugaki Kosaku Takeda 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2008,84(10):452-456
The X-ray crystal structure of natural commelinin is investigated. The results demonstrate that commelinin is a tetranuclear (4 Mg2+) metal complex, in which two Mg2+ ions chelate to six anthocyanin molecules, while the other two Mg2+ ions bind to six flavone molecules, stabilizing the commelinin complex, a new type of supramolecular complex. 相似文献
23.
24.
Consider the impingement of time harmonic flexural waves on a through crack in a soft ferromagnetic plate the surface of which is subjected to a uniform magnetic field at normal incidence. Mindlin's plate theory is used to account for the magneto-elastic interaction. For an incident wave that gives rise to moments symmetric about the crack plane, Fourier transforms are applied reducing the mixed boundary value problem to a Fredholm integral equation that can be solved numerically. The dynamic moment intensity factor versus frequency is computed to exhibit the influence of the magnetic field. 相似文献
25.
M. Koizumi T. T. Inamura K. Morita M. Takami M. Wakasugi A. Yoshida M. Azuma H. Katsuragawa T. Horiguchi T. Ishizuka I. Nakamura M. Nakaoka A. Iivonen K. Valli S. Matsuki T. Murayama K. Shimomura T. Shinozuka I. Sugai Y. Tagishi 《Hyperfine Interactions》1992,74(1-4):181-191
We have constructed a fast atomic-beam collinear laser spectroscopy system connected to the on-line isotope separator facility
GARIS/IGISOL at RIKEN. This system is potentially powerful in studying refractory elements. To test the system, an off-line
collinear experiment was made on stable Hf isotopes produced by means of laser ablation technique. For production of radioactive
Hf isotopes, the use of the inverse kinematics of a fusion reaction,9Be(166Er,xn)175-x
Hf, was investigated. The radioactive isotope169Hf was successfully extracted from GARIS/IGISOL and accelerated up to 30 keV. 相似文献
26.
Hiroshi Kojima Kosaku Sakeda Teijiro Ichimura Masao Takayanagi 《Journal of Molecular Structure》2003,655(1):185-190
Laser-induced fluorescence (LIF) excitation spectra of m-methylanisole in a supersonic jet were measured. Two series of progressions were observed in the spectrum, originating at 36048 and 36115 cm−1, which were successfully assigned to the transitions to the methyl internal rotational vibronic levels of the two isomers, i.e. cis and trans isomers, with the aid of hole-burning spectrum measurements and quantum-chemical calculations. The progression for the trans isomer was observed up to the 6a1 band, while only the 3a1 band in addition to the 0a1 and 1e bands was observed for the cis isomer. This finding can be explained by the conformational change upon the electronic excitation; the 60° rotation of the methyl torsional angle takes place for the trans isomer but not for the cis isomer. 相似文献
27.
An enzyme immunoelectrode for the amperometric determination of serum insulin is described. The device consists of an immunoreactive membrane combined with a hydrogen peroxide electrode. The surface of a microporous hydrophobic polypropylene membrane is modified by water vapour plasma treatment to make it partially hydrophilic. Subsequent treatment with octamethylenediamine and glutaraldehyde enables the surface of this membrane to interact with various proteins. Anchoring of the antibody to Protein A immobilized on the membrane was effective for immunoreactivity. 相似文献
28.
Toshikazu Kaise Hiroshi Yamauchi Yoshiya Horiguchi Takayuki Tani Shigenobu Watanabe Teruhisa Hirayama Shozo Fukui 《应用有机金属化学》1989,3(3):273-277
The acute toxicity of methylarsonic acid, CH3AsO(OH)2 (MAA), dimethylarsininc acid, (CH3)2AsO(OH) (DMAA), and trimethylarsine oxide, (CH3)3AsO (TMAO), were examined in mice with oral administration. The LD50 values of MAA, DMAA and TMAO were 1.8, 1.2 and 10.6 g kg?1 respectively. The toxicity of MAA and DMAA was very much lower than that for inorganic arsenic compounds. It was shown that TMAO has a similar acute toxicity to arsenobetaine. On the other hand, when the mice were administered 14.4 g kg?1 of TMAO once only orally, a garlic-like odor (trimethylarsine, (CH3)3As) was definitely detectable in the exhalation of the animals by the human olfactory sense within about a few minutes. 相似文献
29.
T. Horiguchi 《Physica A》1983,120(3):600-608
A decorated Ising model with classical vector spins on a square lattice is investigated in detail. The partition function is reduced to the one of the Ising model with effective exchange integrals. Three successive phase-transition temperatures are obtained and four states, namely, paramagnetic, antiferromagnetic, again paramagnetic and ferromagnetic states are realized as the temperature is decreased. For systems on other two- and three-dimensional loose-packed lattices, the situation is the same as the system on the square lattice. 相似文献
30.