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121.
122.
The polarized intensity enhancement of the light backscattered multiply from a fractal aggregate of particles is numerically investigated using Monte Carlo simulations. It is confirmed only for the co-polarized intensity component that an effective mean free pathlength lD defined for a fractal medium has the same physical meaning as a mean free pathlength l for a homogeneously random medium. Furthermore, co- and crosspolarized components of the backscattering intensity enhancement decrease in accordance with θ2.16-1.03D and θ4-1.8D in the far-field plane and with ζ0.93D-3.94 and ζ1.07D-3.98 in the boundary plane between the scattering medium and the air. Therefore, the two-dimensional Fourier transform relation is satisfied only between the co-polarized intensity distributions in the far-field and the boundary planes but not the cross-polarized ones with the accuracy of the numerical simulation. Finally, we notice the applicability of the enhanced backscattering light to estimating the dimension of the absorbent fractal medium on the basis of the result that the slope of the intensity decay of the intensity peak is directly proportional to the dimension of the medium but is independent of the absorption. 相似文献
123.
124.
A complete undirected graph of order n has Hamilton cycles. We consider the diameter of a transition graph whose vertices correspond to those Hamilton cycles and any
of two vertices are adjacent if and only if the corresponding Hamilton cycles can be transformed each other by exchanging
two edges. Moreover, we consider several transition graphs related to it.
Received: November 4, 1999 Final version received: August 28, 2000 相似文献
125.
Negami and Kawagoe has already defined a polynomial
associated with each graphG as what discriminates graphs more finely than the polynomialf(G) defined by Negami and the Tutte polynomial. In this paper, we shall show that the polynomial
includes potentially the generating function counting the independent sets and the degree sequence of a graphG, which cannot be recognized fromf(G) in general, and discuss on
of treesT with observations by computer experiments. 相似文献
126.
Katsuhiro Akiyama 《Tetrahedron letters》2004,45(39):7217-7220
Two types of palladium complexes, cationic and neutral (R)-DABNTf-Pd(CH3CN)2 were examined as chiral catalysts for enantioselective Claisen rearrangement. DABNTf-Pd(CH3CN)2 complex gave high enantio- and anti-diastereoselectivity, and good yield. This Claisen rearrangement should proceed via six-membered boat transition state through bi-dentate coordination to the Pd catalyst. 相似文献
127.
Setsuko Nakamura Takuto Yamawaki Katsuhiro Kusaka Takuhiro Otsuka Tomoji Ozeki 《Journal of Cluster Science》2006,17(2):245-256
Tetraphenylphosphonium salts of protonated tetradecavanadophosphate (PV14) anions, [(C6H5)4P]4H5PV14O42·5H2O (1) and [(C6H5)4P]2H7PV14O42·6H2O (2), have been synthesized and their crystal structures have been determined. Compound 1 crystallizes in triclinic, P1 with a=12.7866(1), b=15.5261(2), c=16.0730(3) ?, α=109.358(1), β=98.411(1), γ=110.040(1)°. Synchrotron radiation X-ray diffraction revealed that compound 2 crystallizes in monoclinic, P21/c with a=16.821(1), b=25.163(2), c=18.817(1) ?, β=109.992(2)°. In compound 1, the PV14 anions are linked into a one-dimensional chain structure by water molecules of crystallization. In compound 2, hydrogen bonds directly link PV14 anions into a zigzag chain, which are then woven into a three-dimensional network by hydrogen bonds bridged by water molecules.Dedicated to Professor Michael T. Pope on the occasion of his retirement, in recognition of his outstanding contributions to the polyoxometalate chemistry. 相似文献
128.
Daisuke Uemura Katsuhiro Ueda Yoshimasa Hirata Hideo Naoki Takashi Iwashita 《Tetrahedron letters》1981,22(20):1909-1912
The structures of two degradation products of N-(p-bromobenzoyl) palytoxin were elucidated, and then the sequences of those fragments were determined. 相似文献
129.
Yoshikazu Sugihara Katsuhiro Hashimoto Masahiro Yoshiakwa Ichiro Murata 《Tetrahedron letters》1982,23(18):1925-1928
6,9-Dihydro-6,9-ethenocyclohepta[gh]phenalen-1-one () has been synthesised starting from the Diels-Alder adduct () of acepleiadiene () and maleic anhydride through 10 steps with reasonable yields. Spectroscopic properties of suggestged the intramolecular electron supply from the remote ethylenes to the phenalenone π-systems in the ground-state of this molecule. 相似文献
130.
Abstract— Quenching of excited state of Ru(bpy)2 (poly-4-methyl-4'-vinyl-2,2'-bipyridine)Cl2 by sodium anthraquinone-2-sulfonate was found to be a static process. The quenching was interpreted by application of a modified Perrin model. Radius of the quenching sphere was estimated to correspond to 6.65 monomer units and was unchanged on varying the Ru2 + content of the polymer. Energy migration along the polymer chain was denied. 相似文献