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排序方式: 共有159条查询结果,搜索用时 15 毫秒
91.
Vasileios A Dimitriou Andreas C Georgiou Nikolas Tsantas 《The Journal of the Operational Research Society》2015,66(6):993-1006
The present paper employs the Multivariate Homogeneous Markov System (MHMS) in the context of Markov manpower planning modelling. The system is regulated by an embedded multivariate Markov process that allows us to distinguish employees’ mobility patterns that take place either within or among the existing divisions (departments) of an organization. The motivation behind this step arises from the generalization of univariate Markov manpower planning models in which the organization is considered a single (probably hierarchical) group and from the fact that departmental mobility is actually common in most realistic establishments. The first part of the paper presents the functional relations of the MHMS governing intra/inter-departmental transitions. Using these functional forms, we proceed by studying the system’s equilibrium behaviour. This asymptotic analysis reveals the inherent tendencies of the system to reach the limiting structures of specific forms and properties under conditions imposed in the long run. 相似文献
92.
Häller LJ Kaltsoyannis N Sarsfield MJ May I Cornet SM Redmond MP Helliwell M 《Inorganic chemistry》2007,46(12):4868-4875
Phosphinimine ligands (Cy3PNH) readily react with UO2Cl2(THF)3 (THF=tetrahydrofuran) to give UO2Cl2(Cy3PNH)2, which contains strong U-N interactions and exists as cis and trans isomers in the solid and solution state. Solution NMR experiments and computational analysis both support the trans form as the major isomer in solution, although the cis isomer becomes more stabilized with an increase in the dielectric constant of the solvent. Mayer bond orders, energy decomposition analysis, and examination of the molecular orbitals and total electron densities support a more covalent bonding interaction in the U-NHPCy3 bond compared with the analogous bond of the related U-OPCy3 compounds. 相似文献
93.
Vinzenz Bildstein Roman Gernh?user Thorsten Kr?ll Reiner Krücken Kathrin Wimmer Piet Van Duppen Mark Huyse Nikolas Patronis Riccardo Raabe 《The European Physical Journal A - Hadrons and Nuclei》2012,48(6):1-10
The potential barrier impeding the spontaneous emission of protons in the proton radioactive nuclei is calculated as the sum of nuclear, Coulomb and centrifugal contributions. The nuclear part of the proton-nucleus interaction potential is obtained in the energy density formalism using the Skyrme effective interaction that results into a simple algebraic expression. The half-lives of the proton emitters are calculated for the different Skyrme sets within the improved WKB framework. The results are found to be in reasonable agreement with the earlier results obtained for more complicated calculations involving finite-range interactions. 相似文献
94.
Yardibi T Li J Stoica P Zawodny NS Cattafesta LN 《The Journal of the Acoustical Society of America》2010,127(5):2920-2931
Microphone arrays are commonly used for noise source localization and power estimation in aeroacoustic measurements. The delay-and-sum (DAS) beamformer, which is the most widely used beamforming algorithm in practice, suffers from low resolution and high sidelobe level problems. Therefore, deconvolution approaches, such as the deconvolution approach for the mapping of acoustic sources (DAMAS), are often used for extracting the actual source powers from the contaminated DAS results. However, most deconvolution approaches assume that the sources are uncorrelated. Although deconvolution algorithms that can deal with correlated sources, such as DAMAS for correlated sources, do exist, these algorithms are computationally impractical even for small scanning grid sizes. This paper presents a covariance fitting approach for the mapping of acoustic correlated sources (MACS), which can work with uncorrelated, partially correlated or even coherent sources with a reasonably low computational complexity. MACS minimizes a quadratic cost function in a cyclic manner by making use of convex optimization and sparsity, and is guaranteed to converge at least locally. Simulations and experimental data acquired at the University of Florida Aeroacoustic Flow Facility with a 63-element logarithmic spiral microphone array in the absence of flow are used to demonstrate the performance of MACS. 相似文献
95.
Fortier S Kaltsoyannis N Wu G Hayton TW 《Journal of the American Chemical Society》2011,133(36):14224-14227
Treatment of the U(III)-ylide adduct U(CH(2)PPh(3))(NR(2))(3) (1, R = SiMe(3)) with TEMPO generates the U(V) oxo metallacycle [Ph(3)PCH(3)][U(O)(CH(2)SiMe(2)NSiMe(3))(NR(2))(2)] (2) via O-atom transfer, in good yield. Oxidation of 2 with 0.85 equiv of AgOTf affords the neutral U(VI) species U(O)(CH(2)SiMe(2)NSiMe(3))(NR(2))(2) (3). The electronic structures of 2 and 3 are investigated by DFT analysis. Additionally, the nucleophilicity of the oxo ligands in 2 and 3 toward Me(3)SiI is explored. 相似文献
96.
We simulate directional solidification using a phase-field model solved with adaptive mesh refinement. For small surface tension anisotropy directed at 45 degrees relative to the pulling direction we observe a crossover from a seaweed to a dendritic morphology as the thermal gradient is lowered, consistent with recent experimental findings. We show that the morphology of crystal structures can be unambiguously characterized through the local interface velocity distribution. We derive semiempirically an estimate for the crossover from seaweed to dendrite as a function of thermal gradient and pulling speed. 相似文献
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A Selective Immunosensor for D‐dimer Based on Antibody Immobilized on a Graphene Electrode with Incorporated Lipid Films 下载免费PDF全文
Georgia‐Paraskevi Nikoleli Dimitrios P. Nikolelis Nikolaos Tzamtzis Nikolas Psaroudakis 《Electroanalysis》2014,26(7):1522-1527
The present article describes a miniaturized potentiometric D‐dimer biosensor on graphene nanosheets with incorporated lipid films. The graphene electrode was used for the development of a very selective and sensitive immunosensor for the detection of D‐dimer by immobilizing the mouse anti human D‐dimer antibody on stabilized lipid films. The immunosensor responded for the wide range of D‐dimer concentrations with fast response time of ca. 15 s. The presented potentiometric D‐dimer biosensor is easy to construct and exhibits good reproducibility, reusability, selectivity, rapid response times, long shelf life and high sensitivity of ca. 59 mV/decade over the D‐dimer logarithmic concentration range from 10?6 μg/L to 10?3 μg/L. 相似文献