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61.
Ohno O Chiba T Todoroki S Yoshimura H Maru N Maekawa K Imagawa H Yamada K Wakamiya A Suenaga K Uemura D 《Chemical communications (Cambridge, England)》2011,47(46):12453-12455
Novel sesquiterpene alkaloids, halichonines A (1), B (2), and C (3), were identified from the marine sponge Halichondria okadai Kadota. By spectroscopic analyses and synthesis, their structures were revealed to include a 6,6-bicyclic ring system and two prenylated amine moieties. In addition, 2 induced apoptosis in HL60 human leukemia cells. 相似文献
62.
Yasunori Maekawa 《Journal of Mathematical Fluid Mechanics》2011,13(4):515-532
We study a linearized operator of the equation for the axisymmetric Burgers vortex which gives a stationary solution to the
three dimensional Navier–Stokes equations with an axisymmetric background straining flow. It is numerically known that the
Burgers vortex obtains better stabilities as the circulation number (or the vortex Reynolds number) is increasing. Although
the global stability of the axisymmetric Burgers vortex is already proved rigorously, mathematical understanding of this numerical
observation has been lacking. In this paper we study a linearized operator that includes the circulation number as a parameter,
and prove that if the operator is restricted on a suitable invariant subspace, then its spectrum moves to the left as the
circulation number goes to infinity. As an application, we show that the axisymmetric Burgers vortex with a high rotation
has a better stability, in the sense that the non-radially symmetric part of solutions to the associated evolution equation
decays faster in time if the circulation number is sufficiently large. 相似文献
63.
A new approach to analyze the electronic structure around the local defects in a polymer chain is developed based on the cluster-series model. In this approach, by extending the cluster molecule to both sides of the defect, the size effect on electronic structure can be estimated systematically and efficiently. Moreover, through the extension process, the periodicity of electronic structure can be extracted in the form of the periodic pattern of stationary orbitals, which are molecular orbitals unaltered by the extension of the cluster. Such periodic orbitals characterize the bulk states of periodic polymer and the energy band structure can be reconstructed from them. Illustrative analyses of some kinds of local defects in all-trans-polyacetylene are presented at the ab initio STO -3G level. The effects of local defects can be detected by the deviation from periodic bulk states. © 1993 John Wiley & Sons, Inc. 相似文献
64.
65.
Iridium-chiral diphosphine complex catalyzes an enantioselective intramolecular Pauson-Khand-type reaction to give various chiral bicyclic cyclopentenones. The enantioselective reaction proceeds more smoothly and enantioselectively under a lower partial pressure of carbon monoxide. Moreover, aldehyde can be used as a CO source in the enantioselective carbonylative coupling. 相似文献
66.
67.
Images are very useful to obtain diagnostic informations in medical fields. Also by superimposing two or three images obtained from the same patient, various informations, for example a degree of overlapping and anatomical land mark, which can not be found in only one image, can be often found. In this paper characteristics of our trial color television system for the purpose of superimposing X-ray images and/or radionuclide images are described. This color television system, superimposing two images in each different color consists of two monochromatic vidicon cameras and 20 inches conventional color television in which only two simple video amplifier circuits are added. Signals from vidicon cameras are amplified about 40 dB and are directly applied to cathode terminals of color CRT in the television. This system is very simple and economical color displays, and enhance a degree of overlapping and displacement between images. As one of typical clinical applications, pancreas images were superimposed in color by this method. As a result, size and position of pancreas was enhanced. Also X-ray image and radionuclide image were superimposed to find exactly the position of tumors. Furthermore this system was very useful for color display of multinuclides scintigraphy. 相似文献
68.
Liu SQ Kuroda-Sowa T Konaka H Suenaga Y Maekawa M Mizutani T Ning GL Munakata M 《Inorganic chemistry》2005,44(4):1031-1036
Three luminescent silver(I)-oligo(phenylenevinylene) complexes, [Ag2(bmsb)(ClO4)2] (1), [Ag2(bmsb)(H2O)4](BF4)2 (2), and [Ag2(bdb)(CF3SO3)2] (3) (bmsb = 1, 4-bis(methylstyryl)benzene, bdb = 4,4'-bis(2, 5-dimethylstryryl)biphenyl), have been synthesized and structurally characterized. Complexes 1 and 2 are 2D networks with unique metallocyclophane motifs. Complex 3 affords a 2D zigzag sheet, in which silver triflates form tubelike double chains and bdb molecules act as linkages. Complex 2 exhibits high electric conductivity because of columnar aromatic stackings formed through intra- and intermolecular pi-pi interactions. Complexes 1-3 in the solid state exhibit luminescence, of which excitation and emission maxima are shifted to longer wavelength as compared to those of the corresponding metal-free ligands. 相似文献
69.
70.
An ion cyclotron drift instability is excited by a cross field current due to Er × B drift of electrons and ion heating is observed in a plasma column in a magnetic field when a dc radial electric field Er is applied. 相似文献