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941.
A graph G is minimal harmoniously colorable if it has a proper vertex coloring in which each pair of colors occurs exactly once on an edge. In particular, if D is a 2-design we consider the graph G whose vertices are the points and blocks of D and where two vertices of G are adjacent if and only if the corresponding elements of D are incident. It will be shown that if D is symmetric then G is minimal harmoniously colorable if and only if D is a Hadamard design with corresponding Hadamard matrix of a certain form. We obtain some results if D is nonsymmetric, and construct two classes of nonsymmetric minimal harmoniously colorable designs. © 1994 John Wiley & Sons, Inc. 相似文献
942.
943.
Carina Sinclér Delfino Wanessa Christine Souza-Zaroni Silmara Aparecida Milori Corona Jesus Djalma Pécora Regina Guenka Palma-Dibb 《Applied Surface Science》2006,252(24):8476-8481
The aim of this study was to evaluate in vitro the influence of Er:YAG laser energy variation to cavity preparation on the morphology of enamel/adhesive system interface, using SEM. Eighteen molars were used and the buccal surfaces were flattened without dentine exposure. The specimens were randomly assigned to two groups, according to the adhesive system (conventional total-etching or self-etching), and each group was divided into three subgroups (bur carbide in turbine of high rotation, Er:YAG laser 250 mJ/4 Hz and Er:YAG laser 300 mJ/4 Hz) containing six teeth each. The enamel/adhesive system interface was serially sectioned and prepared for SEM. The Er:YAG laser, in general, produced a more irregular adhesive interface than the control group. For Er:YAG laser 250 mJ there was formation of a more regular hybrid layer with good tag formation, mainly in the total-etching system. However, Er:YAG laser 300 mJ showed a more irregular interface with amorphous enamel and fused areas, for both adhesive systems. It was concluded that cavity preparation with Er:YAG laser influenced on the morphology of enamel/adhesive system interface and the tissual alterations were more evident when the energy was increased. 相似文献
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946.
Vinzant Todd B. Ponfick Lisa Nagle Nick J. Ehrman Christine I. Reynolds James B. Himmel Michael E. 《Applied biochemistry and biotechnology》1994,45(1):611-626
Applied Biochemistry and Biotechnology - Simultaneous saccharification and fermentation (SSF) is recognized as an efficient approach to the cost-effective conversion of biomass to fuel ethanol.... 相似文献
947.
David G. Glynn Christine M. O'Keefe Tim Penttila Cheryl E. Praeger 《Geometriae Dedicata》1996,59(3):223-241
This paper is a contribution to the classification of ovoids. We show, under some rather technical assumptions, that if an ovoid of PG(3, q) has a pencil of monomial ovals, then it is either an elliptic quadric or a Tits ovoid. Further, we show that if an ovoid of PG(3, q) has a bundle of translation ovals, again under some extra assumptions, then the ovoid is an elliptic quadric or a Tits ovoid. 相似文献
948.
949.
Christine Bessenrodt 《Annals of Combinatorics》2002,6(2):119-124
Recently Stembridge obtained the classification of multiplicity-free products of Schur functions, and thus of multiplicity-free outer products of irreducible characters of the symmetric groups. In this paper, the multiplicity-free products of Schur P-functions are classified, and then this is applied to the case of projective outer products of spin characters of the double covers of the symmetric groups. 相似文献
950.
Christine K. F. Hermann Yesh P. Sachdeva James F. Wolfe 《Journal of heterocyclic chemistry》1987,24(4):1061-1065
Reaction of halogenated pyridines, quinolines, pyrimidines, and pyrazines with potassiophenylacetonitrile ( 5 ) in liquid ammonia under near-uv irradiation affords secondary nitriles, which then undergo oxidative decyanation under phase-transfer catalytic conditions to afford aryl hetaryl ketones in excellent yields. 相似文献