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991.
《Physics letters. [Part B]》2005,610(3-4):192-198
Based on a sample of 5.8×107 J/ψ events taken with the BESII detector, the branching fractions of J/ψ→2(π+π−)η and J/ψ→3(π+π−)η are measured for the first time to be (2.26±0.08±0.27)×10−3 and (7.24±0.96±1.11)×10−4, respectively. 相似文献
992.
993.
利用13C NMR对抗冲聚丙烯的微结构进行了研究.结果表明,由于抗冲聚丙烯聚合工艺的差别,4个抗冲聚丙烯样品中的乙烯链段的序列分布也不同.根据抗冲聚丙烯的13C NMR谱,计算出了丙烯段的次甲基和甲基的峰强度,由此建立了表征抗冲聚丙烯共聚物中丙烯链段的立构规整度的方法. 相似文献
994.
995.
Shanjia Xu Fenghua Zheng 《International Journal of Infrared and Millimeter Waves》1997,18(6):1223-1240
The multimode network method is used to analyze the radiation characteristics of the leaky-wave antenna consisting of multilayer
dielectric periodic structure with arbitrary dielectric distributions in each layer. The eigenfunction of each periodic layer
is determined by Floquet theorem; and the mode matching combining with generalized transverse resonant method are used to
derive the dispersion equation of the leaky-wave antenna. The complex transmission constant is calculated by Newton iterative
method and the radiation characteristics of the antenna are obtained. Some antenna structures are analyzed and useful guidelines
for design of the leaky-wave antennas are suggested. 相似文献
996.
团簇LaO的理论研究 总被引:3,自引:3,他引:0
采用密度泛函理论研究LaO团簇体系。中性分子LaO的基态是两重态(2Σ),阴离子LaO-和阳离子LaO 的基态都是单重态(1Σ)。使用不同的方法计算团簇LaO的电子亲和能和电离能。计算结果表明用BLYP方法和弥散极化基组计算结果和实验数据吻合较好。用含时密度泛函理论计算团簇LaO的低能激发态,从理论上归属LaO-的光电子能谱的谱峰和LaO的吸收光谱的谱峰。计算得到与实验一致的结果。 相似文献
997.
《Chaos, solitons, and fractals》2005,23(3):989-995
We prove that a continuous flow with the average-shadowing property is chain transitive and a Lyapunov stable continuous flow with the average-shadowing property is a minimal flow. 相似文献
998.
《European Journal of Operational Research》2006,175(2):1311-1320
In this paper, we conduct simulation experiments to evaluate the performance of two alternative uses of the super-efficiency procedure in Data Envelopment Analysis (DEA). The first is for outlier identification and the second is for ranking efficient units. We find that the ranking procedure does not perform satisfactorily. In fact, the correlations between the true efficiency and the estimated super-efficiency are negative for the subset of efficient observations, and the conventional DEA model performs as well as the super-efficiency DEA model when all observations are considered. However, when data are contaminated with outliers, the use of the super-efficiency model to identify and remove outliers results in more accurate efficiency estimates than those obtained from the conventional DEA estimation model. 相似文献
999.
Let f(2m,k) be the Maximum k-diameter of k-regular k-connected graphs on 2m vertices. In this paper we give an algorithm and prove that we can construct k-regular k-connected graphs on 2m vertices with the maximum k-diameter using it. We also prove some known results about f(2m,k) and verify that we can get some unknown values of f(2m,k) by our algorithm.
Received: December 1, 2000 Final version received: March 12, 2002
Acknowledgments. We thank the referee for many useful suggestions. 相似文献
1000.
不可压N-S方程的差分流线扩散法 总被引:2,自引:0,他引:2
In this paper, a Finite-Difference Streamline-Diffusion (FDSD as short) scheme for the incompressible Navier-Stokes Equations is constructed with linear finite element spaces. The analysis showes that the scheme considered has good stability and higher accuracy than the standard finite elemnet method. 相似文献