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排序方式: 共有116条查询结果,搜索用时 15 毫秒
111.
112.
Erdal Karapınar Salvador Romaguera Kenan Taş 《Central European Journal of Mathematics》2013,11(3):552-560
We prove a fixed point theorem for cyclic orbital generalized contractions on complete metric spaces from which we deduce, among other results, generalized cyclic versions of the celebrated Boyd and Wong fixed point theorem, and Matkowski fixed point theorem. This is done by adapting to the cyclic framework a condition of Meir-Keeler type discussed in [Jachymski J., Equivalent conditions and the Meir-Keeler type theorems, J. Math. Anal. Appl., 1995, 194(1), 293–303]. Our results generalize some theorems of Kirk, Srinavasan and Veeramani, and of Karpagam and Agrawal. 相似文献
113.
We investigate the creation rate of massive spin-1 bosons in the de Sitter universe by a time-dependent electric field via the Duffin–Kemmer–Petiau (DKP) equation. Complete solutions are given by the Whittaker functions and particle creation rate is computed by using the Bogoliubov transformation technique. We analyze the influence of the electric field on the particle creation rate for the strong and vanishing electric fields. We show that the electric field amplifies the creation rate of charged, massive spin-1 particles. This effect is analyzed by considering similar calculations performed for scalar and spin-1/2 particles. 相似文献
114.
115.
Determination of tree ring chemistry using Neutron Activation Analysis (NAA) is part of an ongoing research between Penn State
University (PSU) and Cornell University, The Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology.
Tree-ring chemistry yields valuable data for environmental event signatures. These signatures are a complex function of elemental
concentration. To be certain about concentration of signature elements, it is necessary to perform the measurements and corrections
with the lowest error and maximum accuracy possible. Accurate and precise values of energy dependent neutron flux at dry irradiation
tubes and detector efficiency for tree ring sample are calculated for Penn State Breazeale Reactor (PSBR). For the calculation
of energy dependent and self shielding corrected neutron flux, detailed model of the TRIGA Mark III reactor at PSU with updated
fuel compositions was prepared using the MCNP utility for reactor evolution (MURE) libraries. Dry irradiation tube, sample
holder and sample were also included in the model. The thermal flux self-shielding correction factors due to the sample holder
and sample for were calculated and verified with previously published values. The Geant-4 model of the gamma spectroscopy
system, developed at Radiation Science and Engineering Center (RSEC), was improved and absolute detector efficiency for tree-ring
samples was calculated. 相似文献
116.
Kenan DJ Walsh EB Meyers SR O'Toole GA Carruthers EG Lee WK Zauscher S Prata CA Grinstaff MW 《Chemistry & biology》2006,13(7):695-700
Amphiphilic macromolecules containing a polystyrene-adherent peptide domain and a cell-repellent poly(ethylene glycol) domain were designed, synthesized, and evaluated as a cytophobic surface coating. Such cytophobic, or cell-repellent, coatings are of interest for varied medical and biotechnological applications. The composition of the polystyrene binding peptide domain was identified using an M13 phage display library. ELISA and atomic force spectroscopy were used to evaluate the binding affinity of the amphiphile peptide domain to polystyrene. When coated onto polystyrene, the amphiphile reduced cell adhesion of two distinct mammalian cell lines and pathogenic Staphylococcus aureus strains. 相似文献