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101.
Hiroaki Miyaoka Yoshinori Hara Ikuo Shinohara Takao Kurokawa Yasuji Yamada 《Tetrahedron letters》2005,46(46):7945-7949
Synthesis of the marine eicosanoid agardhilactone has been achieved. The relative and absolute configuration of agardhilactone was successfully determined. 相似文献
102.
Crown ether-type macrocycles consisting of an enantiopure biarenol derivative and an oligoethylene glycol were synthesized by the Lewis acid-mediated tandem Claisen rearrangement. This is the first example of the successful application of the tandem Claisen rearrangement to the synthesis of enantiopure macrocyclic biarenol derivatives. The enantiopure macrocyclic biarenols were found to form 1:1 complexes with amino acid salts and to discriminate their chirality. 相似文献
103.
104.
Hiroaki Yamamoto Youji Kanie Masakazu Arakawa Keiji Taniguchi 《Applied Physics A: Materials Science & Processing》1990,50(6):577-581
The transmission coefficient and the resonance condition in the one-dimensional rectangular double-, triple-, quadruple-, and quintuple-barrier structures are derived theoretically under the assumption of the constant tunneling effective mass. It is found that the resonance energies are different from the eigenvalues in the quantum well due to coupling between wells in the multiple-barrier (much more than triple-barrier) structures. It is confirmed that the transmission spectrum is a Lorentzian near to energies of resonance. 相似文献
105.
Hiroaki Nitani Masato Yuya Takahiro Ono Takashi Nakagawa Satoshi Seino Kenji Okitsu Yoshiteru Mizukoshi Shuichi Emura Takao A. Yamamoto 《Journal of nanoparticle research》2006,8(6):951-958
A sample of Au–Pd bimetallic nanoparticles supported on γ-Fe2O3 was synthesized in a sonochemically one-pot process. The structural analyses of the synthesized sample were performed by the techniques of X-ray Absorption Fine Structure (XAFS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and UV–vis spectrometry. Results indicated that the synthesized sample formed a core-shell structure in which a gold core was surrounded by a thin palladium shell. The reaction rate constant for the hydrogenation of cyclohexene of the present sample showed higher value than that of Pd nanoparticles supported on γ-Fe2O3 and core-shell structured Au–Pd nanoparticles supported on SiO2. The present sample is a promising catalyst material which has a high catalytic activity. 相似文献
106.
Hiroaki Koga Takeyuki Arai Taisuke Hamada Shigeyoshi Sakaki 《Journal of molecular catalysis. A, Chemical》2003,200(1-2):223-228
In the two-electron reduction of diphenylsulfoxide to diphenylsulfide, which is considered a model reaction of sulfite reduction catalyzed by sulfite reductase, methylviologen-pendent iron(III) porphyrin exhibits much higher catalytic activity than usual iron(III) and manganese(III) tetraphenylporphyrins, while cobalt(II) tetraphenylporphyrin exhibits much less catalytic activity than the others. Discussion about the active species and the reason of the acceleration by methylviologen-pendent is presented. 相似文献
107.
We point out the possibility that reactor measurement of θ13, when combined with high-statistics νe appearance accelerator experiments, can detect leptonic CP violation. Our proposal is based on a careful statistical analysis under reasonable assumptions on systematic errors, assuming 2 years running of the neutrino mode J-PARC → Hyper-Kamiokande experiment and a few years running of a reactor experiment with 100 t detectors at the Kashiwazaki–Kariwa nuclear power plant. We show that the method can be arranged to be insensitive to the intrinsic parameter degeneracy but is affected by the one due to unknown sign of Δm231. 相似文献
108.
109.
Toshiyuki Sato Hidekatsu Yokoyama Hiroaki Ohya Hitoshi Kamada 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,159(2)
An active resonator system operating at 700 MHz, which can attain a high Q for CW-ESR measurements of a high loss sample, was developed. This system consisted of a loop-gap resonator (LGR), a receiver coil, an excitation coil, and a phase tunable amplifier. A part of the RF power at the LGR was picked up by the receiver coil, amplified, and irradiated to the LGR again by the excitation coil, which made up a feedback circuit. Because the feedback circuit provided the energy that canceled the loss in the resonator, the Q of the active resonator system increased. When a sample tube (inner diameter, 20 mm; axial length, 31 mm) containing a nitroxide radical and physiological saline solution was placed in the resonator, the Q could be varied from 55 to 4000. It was possible to obtain a Q of the active resonator system with sample that was higher than that of the value of the LGR without a sample in a no-feedback condition. The ESR signal intensity increased up to 7 times with the increase in Q. The sensitivity increased up to 50%, which was a much smaller advance than that of the Q, because the noise level also increased with the increase in signal intensity. 相似文献
110.
A waveguide-type optical frequency shifter based on a rotating half-wave plate is proposed. The underlying principle can be used to realize a bit-rate-free and modulation-code-free optical frequency shifter. The waveguide was formed along the ≪1 1 1> direction on a GaAs (1 1 0) substrate by molecular beam epitaxy (MBE) and reactive ion beam etching (RIBE). A 10-MHz optical frequency shift with 16 Vp-p applied voltage and 22.5% shift efficiency is demonstrated. 相似文献