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991.
C. Yohannan Panicker Hema Tresa Varghese K. Madhusoodanan Pillai Y. Sheena Mary K. Raju T.K. Manojkumar Anna Bielenica Christian Van Alsenoy 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(5):1559-1565
Fourier-transform-Raman and infrared spectrum of 4-azatricyclo [5.2.2.02,6] undecane-3,5,8-trione were recorded and analyzed. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. The first hyperpolarizability, predicted infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with reported values of similar structures which makes this compound an attractive object for future studies of nonlinear optics. Optimized geometrical parameters of the compound are in agreement with similar reported structures. The red shift of the NH stretching wavenumber in the infrared spectrum from the computational wavenumber indicates the weakening of NH bond. 相似文献
992.
993.
In this article we answer a question proposed by Gelfond in 1968. We prove that the sum of digits of squares written in a
basis q ⩾ 2 is equidistributed in arithmetic progressions. 相似文献
994.
995.
996.
997.
The set of doubly-stochastic quantum channels and its subset of mixtures of unitaries are investigated. We provide a detailed
analysis of their structure together with computable criteria for the separation of the two sets. When applied to O(d)-covariant channels this leads to a complete characterization and reveals a remarkable feature: instances of channels which
are not in the convex hull of unitaries can become elements of this set by either taking two copies of them or supplementing
with a completely depolarizing channel. These scenarios imply that a channel whose noise initially resists any environment-assisted
attempt of correction can become perfectly correctable. 相似文献
998.
999.
1000.
Walter J. Gutjahr Stefan Katzensteiner Peter Reiter Christian Stummer Michaela Denk 《Central European Journal of Operations Research》2008,16(3):281-306
This paper presents a new model for project portfolio selection, paying specific attention to competence development. The
model seeks to maximize a weighted average of economic gains from projects and strategic gains from the increment of desirable
competencies. As a sub-problem, scheduling and staff assignment for a candidate set of selected projects must also be optimized.
We provide a nonlinear mixed-integer program formulation for the overall problem, and then propose heuristic solution techniques
composed of (1) a greedy heuristic for the scheduling and staff assignment part, and (2) two (alternative) metaheuristics
for the project selection part. The paper outlines experimental results on a real-world application provided by the E-Commerce
Competence Center Austria and, for a slightly simplified instance, presents comparisons with the exact solution computed by
CPLEX. 相似文献