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911.
Takao Asano Takao Nishizeki P.D Seymour 《Journal of Combinatorial Theory, Series B》1984,37(3):290-293
Tutte found an excluded minor characterization of graphic matroids with five excluded minors. A variation on Tutte's result is presented here. Let {e, f, g} be a circuit of a 3-connected nongraphic matroid M. Then M has a minor using e, f, g isomorphic to either the 4-point line, the Fano matroid, or the bond matroid of K3,3. 相似文献
912.
A new technique of alternate two-wavelength oscillation of a CO2 laser is discussed for application to various differential absorption spectroscopic measurements. Power-balanced, two-adjacent branch oscillation using a single CO2 laser was achieved by modulating the angle of a mirror inside the laser cavity and adjusting automatically the cavity length. The two-wavelength modulation frequency was extended up to about 1.2 kHz. Line tuning and power modulation characteristics were studied. The laser was used in long-path differential absorption measurements of ethylene air pollution molecules to demonstrate the capability of this power-balanced, two-wavelength oscillation method. The minimum detectable absorption was nearly 1×10–3 in a short-path cell experiment and 3×10–3 in a long-path experiment. 相似文献
913.
Our new theory of fluctuation was applied to the undamped spiking in lasers with single mode saturable absorption. At the marginal points, which lead to limit cycles, it was found that the irreversible circulation α and the residual circulation α′ diverge together with the variance σ. The model system of this article has effectively three degrees of freedom; however, it was demonstrated that the dominant motion and the fluctuation have two dimensional character in the neighbourhood of a hard mode instability. 相似文献
914.
Takao Nishizeki 《Discrete Mathematics》1981,37(1):105-114
The lower bounds on the cardinality of the maximum matchings of regular multigraphs are established in terms of the number of vertices, the degree of vertices and the edge-connectivity of a multigraph. The bounds are attained by infinitely many multigraphs, so are best possible. 相似文献
915.
916.
917.
918.
Takao Ikariya Yasutoshi Ishikawa Kiyomiki Hirai Sadao Yoshikawa 《Journal of organometallic chemistry》1985,288(3):311-315
The reaction of WCl6/LiAlH4 with imines, R′NCHR, gave tertiary amines, R′N(CH2R)2, and secondary amines, R′NHCHRCH2R. Isotope labeling experiments revealed that the reaction involved two types of azatungstenacyclobutanes, HR and HR, produced from the reaction of an alkylidene tungsten intermediate with the imine CN double bond. Formation of these metallacyclobutanes is highly dependent on the solvent used. 相似文献
919.
Hiroyuki Nakayama Takao Nishizeki Nobuji Saito 《Journal of Algorithms in Cognition, Informatics and Logic》1985,6(3):393-399
Nontrivial lower bounds are given for the computation time of various combinatorial problems on graphs under a linear or algebraic decision tree model. An bound is obtained for a “travelling salesman problem” on a weighted complete graph of n vertices. Moreover it is shown that the same bound is valid for the “subgraph detection problem” with respect to property P if P is hereditary and determined by components. Thus an bound is established in a unified way for a rather large class of problems. 相似文献
920.
Norishige Chiba Takao Nishizeki Nobuji Saito 《Journal of Algorithms in Cognition, Informatics and Logic》1981,2(4):317-327
A simple linear algorithm is presented for coloring planar graphs with at most five colors. The algorithm employs a recursive reduction of a graph involving the deletion of a vertex of degree 6 or less possibly together with the identification of its several neighbors. 相似文献