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821.
The partitional graphs, which are a subclass of the sequential graphs, were recently introduced by Ichishima and Oshima (Math
Comput Sci 3:39–45, 2010), and the cartesian product of a partitional graph and K
2 was shown to be partitional, sequential, harmonious and felicitous. In this paper, we present some necessary conditions for
a graph to be partitional. By means of these, we study the partitional properties of certain classes of graphs. In particular,
we completely characterize the classes of the graphs B
m
and K
m,2 × Q
n
that are partitional. We also establish the relationships between partitional graphs and graphs with strong α-valuations as well as strongly felicitous graphs. 相似文献
822.
Hayashi S Hirano K Yorimitsu H Oshima K 《Journal of the American Chemical Society》2008,130(15):5048-5049
Treatment of tertiary homopropargyl alcohol with aryl halide under palladium catalysis provided arylallenes regioselectively. The reaction includes retro-propargylation, which proceeds in a concerted fashion via a cyclic transition state and transfers the stereochemistry of homopropargyl alcohols through C-C bond cleavage. The present method enables the use of homopropargyl alcohols as allenylmetal equivalents. 相似文献
823.
Yamamoto YS Oshima Y Shinzawa H Katagiri T Matsuura Y Ozaki Y Sato H 《Analytica chimica acta》2008,619(1):8-13
A ball lens hollow-fiber Raman probe (BHRP) is a powerful tool for in vivo nondestructive subsurface analysis of biomedical tissues in a living body. It has confocal-like optical properties, but its collection volume is rather large in comparison with that of a conventional confocal Raman system. Therefore, the obtained Raman spectra have contributions from the upper and lower layers at different rates depending on the thickness of the upper layer when the measurement point is close to the boundary surface of the two layers. In the present study, we describe a methodology to extract quantitative information about the thickness of the subsurface layer structure by using a BHRP combined with the partial least-square regression (PLSR) analysis. The simulation study indicates that distribution of the collection efficiency in the collection volume of the BHRP is similar to a Gaussian distribution. The empirical study suggests that the PLSR model built with only a principal component (PC) 1 based on the linearized depth data gives good prediction. 相似文献
824.
A novel chitosan-based chelating resin modified with tris(2-aminoethyl)amine moiety (CCTS-TAA) was synthesized, and its characteristics in the collection/concentration of mercury was examined. The synthesized resin showed good adsorption toward mercury in a wide pH range, and the adsorbed mercury can be easily eluted by using 2M HNO(3) without any addition of complexing agent. The resin was then packed in a mini-column and the mini-column was installed on a computer-controlled automated-pretreatment (Auto-Pret) system coupled with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) for on-line mercury collection and determination at trace level. 相似文献
825.
A kinetic study has been made of the BF(3)-mediated ring opening of two rigid conformers (alpha and beta) of m- and p-dimethyl-substituted homobenzoquinone epoxides spiro-linked with a twist-boat dibenzocycloheptene ring as compared with the conformationally mobile epoxides bearing diphenyl groups. The rates of the regioselective ring opening were dependent on the topological alignment of the dibenzocycloheptene ring as well as the substitution pattern of the quinone dimethyl groups, indicating pi-aryl participated orbital interaction with the vacant Walsh orbital of the oxirane ring. 相似文献
826.
Regio- and stereoselective hydroamidation of 1-alkynylphosphine sulfides proceeds in the presence of cesium carbonate to provide (E)-2-amino-1-thiophosphinyl-1-alkenes. Asymmetric hydrogenation of the adducts catalyzed by an iridium complex followed by desulfidation yields 2-amino-1-phosphinoalkanes, which offers a new approach to chiral N,P-ligands that will potentially serve as ligands in asymmetric reactions. 相似文献
827.
Oshima T Asahara H Koizumi T Miyamoto S 《Chemical communications (Cambridge, England)》2008,(15):1804-1806
The acid-induced reaction of bis(p-chlorophenyl)homobenzoquinone epoxide gave the dual ipso/ortho intramolecular S(E)2-Ar products associated with pi-aryl participated oxirane ring opening, whereas bis(p-tolyl)- and diphenyl-substituted homologues provided only the ortho products. 相似文献
828.
Palladium-catalysed cis- and trans-silaboration of terminal alkynes has been developed via the addition of (chlorodimethylsilyl)pinacolborane, followed by a one-pot conversion of the chloro group on the silicon atom to an isopropoxy group. 相似文献
829.
M Higuchi K Nakamura S Horike Y Hijikata N Yanai T Fukushima J Kim K Kato M Takata D Watanabe S Oshima S Kitagawa 《Angewandte Chemie (International ed. in English)》2012,51(33):8369-8372
Charged up: A novel porous coordination polymer with a charged organic surface (COS) comprising a zwitterionic organic linker, viologen, has been synthesized. The COS shows strong Lewis acidity accompanied with flexibility, and the isosteric heat of H(2) adsorption is 9.5?kJ?mol(-1) , which is comparable to that of open metal sites (OMSs). 相似文献
830.