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991.
Teobald Kupka Adrianna Mnich Małgorzata A. Broda 《Magnetic resonance in chemistry : MRC》2019,57(8):489-498
Nuclear shieldings and chemical shifts of 5-fluorocytosine (5FC) were predicted in the gas phase and DMSO solution modeled by polarizable continuum model using B3LYP density functional and revised STO(1M)-3G basis set. For comparison, eight arbitrary selected basis sets including STO-3G and medium-size Pople-type and larger dedicated Jensen-type ones were applied. The former basis sets were significantly smaller, but the calculated structural parameters, harmonic vibrational frequencies, were very accurate and close to those obtained with larger, polarization-consistent ones. The predicted 13C and 1H chemical shieldings of 5FC and cytosine, selected as parent molecule, were acceptable (root mean square for 13C chemical shifts in DMSO of about 5 ppm and less) though less accurate than those calculated with large basis sets, dedicated for prediction of nuclear magnetic resonance parameters. 相似文献
992.
On the assumption that the yield criterion of orthotropic materials is isomorphic with Huber-Mises criterion of isotropic materials, we put forward a dimensionless stress yield criterion, and obtained the associated plastic flow law. Using experimental stress-strain curves in various simple stress states, generalized effective stress-strain formulae may be derived correspondingly in various forms. 相似文献
993.
基于粗集—模糊理论的柴油机磨损模式识别 总被引:5,自引:0,他引:5
在总结柴油机磨损模式的磨粒分析基础上,首次提出在柴油机磨损模式识别中采用基于粗集和模糊理论相结合的模式识别方法。在建立磨损形式标准样本库的基础上,利用粗集理论对标准样本知识库进行简化和权重集计算,然后利用模糊理论确定隶属函数,最后给出结论。 相似文献
994.
Projections of random Cantor sets 总被引:1,自引:0,他引:1
K. J. Falconer 《Journal of Theoretical Probability》1989,2(1):65-70
Recently Dekking and Grimmett have used the theories of branching processes in a random environment and of superbranching processes to find the almostsure box-counting dimension of certain orthogonal projections of random Cantor sets. This note gives a rather shorter and more direct calculation, and also shows that the Hausdorff dimension is almost surely equal to the box-counting dimension. We restrict attention to one-dimensional projections of a plane set—there is no difficulty in extending the proof to higher-dimensional cases. 相似文献
995.
This paper develops a nonlinear programming approach to derive the membership functions of the steady-state performance measures in bulk arrival queueing systems with varying batch sizes, in that the arrival rate and service rate are fuzzy numbers. The basic idea is based on Zadeh’s extension principle. Two pairs of mixed integer nonlinear programs (MINLP) with binary variables are formulated to calculate the upper and lower bounds of the system performance measure at possibility level α. From different values of α, the membership function of the system performance measure is constructed. For practice use, the defuzzification of performance measures is also provided via Yager ranking index. To demonstrate the validity of the proposed method, a numerical example is solved successfully. 相似文献
996.
Marilyn Breen 《Periodica Mathematica Hungarica》2007,55(2):169-176
A Krasnosel’skii-type theorem for compact sets that are starshaped via staircase paths may be extended to compact sets that
are starshaped via orthogonally convex paths: Let S be a nonempty compact planar set having connected complement. If every
two points of S are visible via orthogonally convex paths from a common point of S, then S is starshaped via orthogonally convex paths. Moreover, the associated kernel Ker S has the expected property that every two of its points are joined in Ker S by an orthogonally convex path. If S is an arbitrary nonempty planar set that is starshaped via orthogonally convex paths, then for each component C of Ker S, every two of points of C are joined in C by an orthogonally convex path.
Communicated by Imre Bárány 相似文献
997.
用[1]中的方法,我们得到乘子猜想在n=5n1情形时的一些新结果,对此情形下的MacFarland的结论(见[2])作了较大的改进. 相似文献
998.
格的内蕴拓扑与完全分配律 总被引:2,自引:0,他引:2
本文以Scott拓扑,Zariski拓扑,区间拓朴等刻划了完全分配律;获得了格的特殊元的存在性与区间拓扑连通性等之间的众多制约关系,给出了若干应用实例和重要反例. 相似文献
999.
Journal of Global Optimization - 相似文献
1000.
Chat Yin Ho 《Designs, Codes and Cryptography》1991,1(1):69-75
In this paper we investigate how finite group theory, number theory, together with the geometry of substructures can be used in the study of finite projective planes. Some remarks concerning the function v(x)= x
2 + x + 1are presented, for example, how the geometry of a subplane affects the factorization of v(x). The rest of this paper studies abelian planar difference sets by multipliers.Partially supported by NSA grant MDA904-90-H-1013. 相似文献