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51.
戴滨林 《数学物理学报(A辑)》2007,27(5):935-940
该文对高维非初等Mò'bius变换群进行了研究,得到了一些重要性质,给出了几个关于离散准则和代数收敛性的定理. 相似文献
52.
The atomic structures of indium (In) on silicon (Si) (1 0 0)-(2 × 1) surface are investigated by the local density approximation using first-principles pseudopotentials. Total energy optimizations show that the energetically favored structure is the parallel ad-dimer model. The adsorption energy of In on ideal Si(1 0 0)-(1 × 1) surface is significantly higher than that on reconstructed Si(1 0 0)-(2 × 1) surface, suggesting that In adsorption does not break the Si-Si dimer bond of the substrate. When Si surface contains single dimer vacancy defects, In chain will be interrupted, leading to disconnected In nanowires. Displacive adsorption of In on Si(1 0 0) is also considered, and the calculation suggests that interdiffusion of In into Si substrate will not be favorable under equilibrium conditions. 相似文献
53.
在本文中引入了泛代数的二次扩张的概念,解决了TU-EC(A)和UT-EC(A)的存在、真类和基数问题,范畴TU-EC(A)(及UT-EC(A)),并得到了有关二次扩张的几个同构定理,还对一点二次扩张作了讨论。 相似文献
54.
In this paper,the concept of the infinitesimal realization factor is extended to the parameter-dependent performance functions in closed queueing networks. Then the concepts of realization matrix (its elements are called realization factors) and performance potential are introduced,and the relations between infinitesimal realization factors and these two quantities are discussed. This provides a united framework for both IPA and non IPA approaches. Finally,another physical meaning of the service rate is given. 相似文献
55.
制备了纯的、掺0.005、0.01、0.2和0.5wt%Cr2O3的钛酸锶单晶.测量了不同退火条件下的室温透射光谱及6.5K以上的荧光光谱.对晶体的氧化和还原热处理诱导吸收及退火和掺杂浓度对晶体发光的影响进行了较为详细的研究. 相似文献
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57.
Dan Hefetz Michael Krivelevich Tibor Szabó 《Journal of Combinatorial Theory, Series A》2007,114(5):840-853
Let p and q be positive integers and let H be any hypergraph. In a (p,q,H) Avoider-Enforcer game two players, called Avoider and Enforcer, take turns selecting previously unclaimed vertices of H. Avoider selects p vertices per move and Enforcer selects q vertices per move. Avoider loses if he claims all the vertices of some hyperedge of H; otherwise Enforcer loses. We prove a sufficient condition for Avoider to win the (p,q,H) game. We then use this condition to show that Enforcer can win the (1,q) perfect matching game on K2n for every q?cn/logn for an appropriate constant c, and the (1,q) Hamilton cycle game on Kn for every q?cnloglogloglogn/lognlogloglogn for an appropriate constant c. We also determine exactly those values of q for which Enforcer can win the (1,q) connectivity game on Kn. This result is quite surprising as it substantially differs from its Maker-Breaker analog. Our method extends easily to improve a result of Lu [X. Lu, A note on biased and non-biased games, Discrete Appl. Math. 60 (1995) 285-291], regarding forcing an opponent to pack many pairwise edge disjoint spanning trees in his graph. 相似文献
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A method for calculating the number of rotamers of a linear alkane and of the number of rotamers with a given number of gauche conformations along the chain as a function of the total number of atoms in the chain, using general equations, is presented. A graphical method for generating individual rotamers was applied to the homologs up to decane, which has 1134 rotamers. The steric energies calculated by molecular mechanics (MM2 force field) were used as measures of the heat of formation for the coiled conformations relative to the anti conformer for each molecule, whereas the statistical entropy differences were calculated for classes of coiled rotamers grouped by the number of gauche bonds and steric energy. The free energy values calculated from these components show that already at 400 K hexane exists preferentially in conformations containing gauche bonds. For larger chains the free energy advantage for the coiled chains increases very steeply. The implications for the question of reactions of linear alkanes occurring on the surface or inside the channels of small- and medium-pore zeolites are briefly examined. 相似文献
60.