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101.
Tetsutaro Kimachi Eri Torii Rina Ishimoto Ayako Sakue Motoharu Ju-ichi 《Tetrahedron: Asymmetry》2009,20(14):1683-1689
Starting from a reduced lapachol compound, the total synthesis of rhinacanthin A in both racemic and enantioenriched forms is achieved in eight steps without forming any undesired β-lapachone derivatives. For the synthesis of enantioenriched rhinacanthin A, the introduction of the asymmetric center was carried out by using the catalytic asymmetric epoxidation of an unfunctional trisubstituted olefin using Shi’s epoxidation diketal catalyst. The acidic treatment of a derived enantioenriched epoxynaphthol and the following CAN oxidation afforded the target molecule with high enantiomeric purity. 相似文献
102.
The super-Kadomtsev-Petviashvili (SKP) hierarchy is introduced, and the general solutions are explicitly represented in terms of a superdeterminant. It is proved that the SKP hierarchy can be regarded as a dynamical system on a super-Grassmann manifold of infinite dimensions. 相似文献
103.
Desmosine is a crosslinking pyridinium amino acid of elastin, which is a useful biomarker for the diagnosis of chronic obstructive pulmonary disease (COPD) by LC–MS/MS analysis. We previously reported a synthesis of desmosine-d4, which is useful as an internal standard for quantitative LC–MS/MS analysis of desmosines, by deuterogenation of an alkyne group; however, the isotopic purity of the desmosine-d4 was only ca. 50%. The present report describes a new synthesis of desmosine-d4 that improves the isotopic purity to ca. 90% by exchanging the protons of the amino groups to deuterium using deuterogenation. 相似文献
104.
Treatment of alkynes with ortho-formyl and acetyl phenylboronic acids in the presence of a cobalt catalyst resulted in the formation of 2,3-disubstituted indenols in good yields. When aryl silyl alkynes were used, 2-aryl-3-silyl indenols were obtained regioselectively in good yields. 相似文献
105.
Ishikawa T Yoshida N Ueno H Wiedeman M Imai Y Yamaguchi T 《Physical review letters》2011,107(2):028102
Coherent structures appear in a concentrated suspension of swimming bacteria. While transport phenomena in a suspension have been studied extensively, how energy is transported from the individual cell scale to the larger mesoscale remains unclear. In this study, we carry out the first successful measurement of the three-dimensional velocity field in a dense suspension of bacteria. The results show that most of the energy generated by individual bacteria dissipates on the cellular scale. Only a small amount of energy is transported to the mesoscale, but the gain in swimming velocity and mass transport due to mesoscale coherent structures is enormous. These results indicate that collective swimming of bacteria is efficient in terms of energy. This paper sheds light on how energy can be transported toward smaller wave numbers in the Stokes flow regime. 相似文献
106.
Abstract
We have been interested in behaviors of suspended particles in a volatile droplet placed on a smooth substrate. It is known that the particles gather and deposit in the vicinity of the macroscopic contact line of the droplet, which is generally called ‘coffee stain problem’. A convective flow induced by non-uniform evaporation through the interface brings suspended particles toward the pinned contact line in the drying droplet, which forms a ring stain. We have focused on the dynamics of the droplet with/without suspended particles spreading on the solid substrate and on the behaviors of particles in the evaporating droplet. Spreading process of the droplet is significantly affected by the suspended particles. We indicate flow patterns in the droplet, in which the flow exhibits a modal structure with a mode number in the azimuthal direction, and indicate particles depositions after the dryout of the droplet. Three-dimensional particle tracking velocimetry is applied to reconstruct such unique flow patterns in the spreading process of the droplet. Resultant patterns of the particles depositing on the substrate are introduced. 相似文献107.
A. Kolloch T. Geldhauser K. Ueno H. Misawa J. Boneberg A. Plech P. Leiderer 《Applied Physics A: Materials Science & Processing》2011,104(3):793-799
We report on recent insights into the interaction between ultra-fast laser pulses and plasmonic nanoparticles. We discuss
femtosecond near-field ablation as a simple but versatile tool for the nanoscale modification of surfaces and the high-resolution
measurement of a nanostructure’s near field. Two model systems are presented, illustrating the complexity of near-field distributions.
Furthermore, finite difference time domain calculations in combination with absorption spectra provide a deeper insight into
the factors influencing the near-field distribution. For the first time, an almost perfect agreement between the measured
ablation pattern and experiment has been reached for gold triangles with a side length around 500 nm. Additionally, the results
from picosecond laser irradiated plasmonic structures display a new regime of nanoscale laser material processing. We present
first results showing nanometre confined melting induced by laser pulses. 相似文献
108.
109.
Tetsuya Masuda Katsuhisa Mimachi Yoshiomi Nakagami Masatoshi Noumi Yutaka Saburi Kimio Ueno 《Letters in Mathematical Physics》1990,19(3):187-194
Real forms of the quantum universal enveloping algebraU
q
(sl(2)) and a topological quantum group associated with this algebra are discussed. 相似文献
110.
W. Sato H. Ueno A. Taniguchi Y. Itsuki Y. Kasamatsu A. Shinohara K. Asahi Y. Ohkubo 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(3):665-668
The time-differential perturbed angular correlation (TDPAC) method was applied to a study on the behavior of 140Ce atoms implanted in highly oriented pyrolytic graphite (HOPG). Exponential-type gradual attenuation of the directional anisotropy
of the relevant γ-ray cascade was observed in the perturbation patterns. From temperature dependence of the relaxation rate,
a thermally activated dynamic motion of the probe atoms was suggested. 相似文献