排序方式: 共有108条查询结果,搜索用时 15 毫秒
61.
Agostini Pedro Altinoluk Tolga Armesto Néstor 《The European Physical Journal C - Particles and Fields》2019,79(9):1-15
The European Physical Journal C - A generalized theory of electroweak interaction is developed based on the underlying geometrical structure of the tangent bundle with symmetries arising from... 相似文献
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Dizman Serdar Akdemir Tolga Yeşilkanat Cafer Mert Nevruzoglu Vagif Bal Esra Keser Recep 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(6):2533-2544
Journal of Radioanalytical and Nuclear Chemistry - In this study, natural and artificial radioactivity concentrations in sediment samples taken from ?av?at Black Lake located on the... 相似文献
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Tolga Tezcan 《Queueing Systems》2012,71(4):445-467
Optimal control of many-server heterogenous service systems with service times that have a special hyper-exponential distribution, denoted by $H_{2}^{*}$ , which is a mixture of an exponential distribution and a unit point mass at 0, is considered. A?static priority policy that assigns priorities to server pools based on their service time distributions is proposed. This policy is shown to be asymptotically optimal in the many-server heavy-traffic regime in minimizing the total number of customers. 相似文献
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Tolga Bekta? 《European Journal of Operational Research》2012,216(1):83-93
This paper describes new models and exact solution algorithms for the fixed destination multidepot salesmen problem defined on a graph with n nodes where the number of nodes each salesman is to visit is restricted to be in a predefined range. Such problems arise when the time to visit a node takes considerably longer as compared to the time of travel between nodes, in which case the number of nodes visited in a salesman’s tour is the determinant of their ‘load’. The new models are novel multicommodity flow formulations with O(n2) binary variables, which is contrary to the existing formulations for the same (and similar) problems that typically include O(n3) binary variables. The paper also describes Benders decomposition algorithms based on the new formulations for solving the problem exactly. Results of the computational experiments on instances derived from TSPLIB show that some of the proposed algorithms perform remarkably well in cases where formulations solved by a state-of-the-art optimization code fail to yield optimal solutions within reasonable computation time. 相似文献
66.
Adil Tolga Gorgulu Huseyin Cankaya Adnan Kurt Adolfo Speghini Marco Bettinelli Alphan Sennaroglu 《Journal of luminescence》2012,132(1):110-113
We have performed detailed experiments to investigate the spectroscopic properties of a new type of tellurite based host doped with thulium: Tm2O3:(0.70)TeO2–(0.15)K2O–(0.15)Nb2O5 having Tm2O3 concentrations of 0.125, 0.25, 0.5, and 1.0 mol%. By performing a Judd–Ofelt analysis of the absorption bands, we obtained average radiative lifetimes of 2.57±0.20 and 0.35±0.01 ms for the 3H4 and 3F4 levels, respectively. Furthermore, we also observed that an increase in the Tm2O3 concentration from 0.125 to 1.0 mol% results in a decrease of the measured fluorescence lifetime from 814 to 439 μs and from 258 to 47 μs for the 3H4 and 3F4 levels, respectively, due to efficient non-radiative decay. The highest quantum efficiency of 32% was obtained for the sample doped with 0.125 mol% Tm2O3 for the 3H4 level. Results show that cross relaxation becomes important as the ion concentration is increased, leading to the quenching of the 1460-nm band and enhancement of the 1860-nm emission. The highest emission cross section of 6.85×10?21 cm2 measured for the 1860-nm band reveals the potential of this host for the development of 2-μm lasers in bulk glass as well as fiber media. 相似文献
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Tanju Eren Necip Atar Mehmet Lütfi Yola Hassan Karimi-Maleh Alper Tolga Çolak Asim Olgun 《Ionics》2015,21(8):2193-2199
In the present study, we report the green and one-pot synthesis of silver nanoparticles (AgNPs) on as-prepared novel polyoxometalate {[Ni2,5(Hpen)4(PW9O34)]?·?5H2O} (POM) without any reducing agent and its application as improved anode material for lithium-ion batteries (LIBs). The structure of the AgNPs involved POM (AgNPs/POM) nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The synthesized POM was also characterized by elemental analysis and thermal analysis. The electrochemical performances of the POM, AgNPs, and AgNPs/POM composites were measured for charge/discharge specific capacities at different current rates in CR2032 coin-type cells. The prepared AgNPs/POM composite showed a high specific gravimetric capacity of about 1760 mAh g?1 and long-term cycle stability. 相似文献
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Alper Tolga Çolak Okan Zafer Ye?ilelGönül Pamuk Handan GünayOrhan Büyükgüngör 《Polyhedron》2011,30(6):1012-1022
Three Co(II) and Cu(II)-pyridine-2,5-dicarboxylate (pydc) proton transfer compounds with 1,4-butanediamine (ben) and 2,2-dimethylpropane-1,3-diamine (dmpen), trans-(H2ben)[Co(pydc)2(H2O)2]·4H2O (1), trans-(H2dmpen)[Co(pydc)2(H2O)2]·2H2O (2) and (H2ben)2[Cu2(μ-pydc)4(H2O)2] (3) have been synthesized and characterized by the methods of elemental, spectroscopic (IR and UV-Vis), thermal (TG/DTG, DTA) analysis, magnetic measurement and single crystal X-ray diffraction. The crystallographic analysis revealed that the complexes consist of [Co(pydc)2(H2O)2]2− anion, bis(protonated) diamine cation (H2ben for 1 and H2dmpen for 2) and four and two crystal water molecules, respectively. The Co(II) ions are coordinated by two pydc and two aqua ligands. The bis(deprotonated) pydc ligands coordinate to the Co(II) ions through the nitrogen atom of pyridine ring and the oxygen atom of carboxylate group, creating a chelate ring. The distorted octahedral geometries are completed by two trans aqua ligands at axial positions. The molecular structure of the complex 3 consists of dinuclear [Cu2(μ-pydc)4(H2O)2]4− units and bis(protonated) 1,4-butanediammonium cation. In the structure, each Cu(II) ion is coordinated by two nitrogen and two oxygen atoms from two pydc ligands and one oxygen atom from aqua ligand, forming a distorted square pyramidal geometry. 相似文献