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1.
The Bañados‐Teitelboim‐Zanelli (BTZ) black hole model corresponds to a solution of (2+1)‐dimensional Einstein gravity with negative cosmological constant, and by a conformal rescaling its metric can be mapped onto the hyperbolic pseudosphere surface (Beltrami trumpet) with negative curvature. Beltrami trumpet shaped graphene sheets have been predicted to emit Hawking radiation that is experimentally detectable by a scanning tunnelling microscope. Here, for the first time we present an analytical algorithm that allows variational solutions to the Dirac Hamiltonian of graphene pseudoparticles in BTZ black hole gravitational field by using an approach based on the formalism of pseudo‐Hermitian Hamiltonians within a discrete‐basis‐set method. We show that our model not only reproduces the exact results for the real part of quasinormal mode frequencies of (2+1)‐dimensional spinless BTZ black hole, but also provides analytical results for the real part of quasinormal modes of spinning BTZ black hole, and also offers some predictions for the observable effects with a view to gravity‐like phenomena in a curved graphene sheet.
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B. S. Kandemir A. Mogulkoc 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,74(3):391-396
In the variational framework, we study the electronic energy spectrum of
massless Dirac fermions of graphene subjected to one-dimensional oscillating
magnetic and electrostatic fields centered around a constant uniform static
magnetic field. We analyze the influence of the lateral periodic modulations
in one direction, created by these oscillating electric and magnetic fields,
on Dirac like Landau levels depending on amplitudes and periods of the field
modulations. We compare our theoretical results with those found within the
framework of non-degenerate perturbation theory. We found that the technique
presented here yields energies lower than that obtained by the perturbation
calculation, and thus gives more stable solutions for the electronic
spectrum of massless Dirac fermion subjected to a magnetic field
perpendicular to graphene layer under the influence of additional periodic
potentials. 相似文献
3.
Nazl Turan Yücel Ümmühan Kandemir Ümide Demir
zkay
zgür Devrim Can 《Molecules (Basel, Switzerland)》2021,26(11)
Vortioxetine is a multimodal antidepressant drug that affects several brain neurochemicals and has the potential to induce various pharmacological effects on the central nervous system. Therefore, we investigated the centrally mediated analgesic efficacy of this drug and the mechanisms underlying this effect. Analgesic activity of vortioxetine (5, 10 and 20 mg/kg, p.o.) was examined by tail-clip, tail-immersion and hot-plate tests. Motor performance of animals was evaluated using Rota-rod device. Time course measurements (30–180 min) showed that vortioxetine (10 and 20 mg/kg) administrations significantly increased the response latency, percent maximum possible effect and area under the curve values in all of the nociceptive tests. These data pointed out the analgesic effect of vortioxetine on central pathways carrying acute thermal and mechanical nociceptive stimuli. Vortioxetine did not alter the motor coordination of mice indicating that the analgesic activity of this drug was specific. In mechanistic studies, pre-treatments with p-chlorophenylalanine (serotonin-synthesis inhibitor), NAN-190 (serotonin 5-HT1A receptor antagonist), α-methyl-para-tyrosine (catecholamine-synthesis inhibitor), phentolamine (non-selective α-adrenoceptor blocker), and naloxone (non-selective opioid receptor blocker) antagonised the vortioxetine-induced analgesia. Obtained findings indicated that vortioxetine-induced analgesia is mediated by 5-HT1A serotonergic, α-adrenergic and opioidergic receptors, and contributions of central serotonergic and catecholaminergic neurotransmissions are critical for this effect. 相似文献
4.
B. S. Kandemir 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,78(3):393-397
The electronic energy level structure of the corrugated graphene
electron subjected to a magnetic field tilted with respect to the graphene
plane and an in-plane homogeneous magnetic field is investigated
theoretically within the perturbation framework. It is shown that the
anisotropy induced by the tilted magnetic field strongly modifies the Fermi
velocity of the corrugated graphene electron, and the corrugated structure
yields intrinsic Weiss oscillations in both Fermi velocity and the graphene
Landau levels. 相似文献
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6.
Zafer Kandemir Selma Mayda Nejat Bulut 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(5):113
We study the electronic structure and correlations of vitamin B12 (cyanocobalamine) by using theframework of the multi-orbital single-impurity Haldane-Anderson model of atransition-metal impurity in a semiconductor host. The parameters of the effectiveHaldane-Anderson model are obtained within the Hartree-Fock (HF) approximation. Thequantum Monte Carlo (QMC) technique is then used to calculate the one-electron andmagnetic correlation functions of this effective model. We observe that new states forminside the semiconductor gap found by HF due to the intra-orbital Coulomb interaction atthe impurity 3d orbitals. In particular, the lowest unoccupiedstates correspond to an impurity bound state, which consists of states from mainly the CNaxial ligand and the corrin ring as well as the Co eg-like orbitals. We alsoobserve that the Co?(3d) orbitals can develop antiferromagneticcorrelations with the surrounding atoms depending on the filling of the impurity boundstates. In addition, we make comparisons of the HF+QMC data with the density functionaltheory calculations. We also discuss the photoabsorption spectrum of cyanocobalamine. 相似文献
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Arslan Asli Ergenekon Arslan Oguz Kandemir Suheyla Yerel 《Journal of Thermal Analysis and Calorimetry》2021,146(3):1191-1192
Journal of Thermal Analysis and Calorimetry - In the original publication of the article, the following equations has been incorrectly published. The corrected equations are given. 相似文献
10.
B. S. Kandemir A. Mogulkoc 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,74(4):535-541
The very interesting magnetic properties of frustrated magnetic molecules are often hardly
accessible due to the prohibitive size of the related Hilbert spaces. The finite-temperature Lanczos
method is able to treat spin systems for Hilbert space sizes up to 109. Here we first demonstrate
for exactly solvable systems that the method is indeed accurate. Then we discuss the thermal
properties of one of the biggest magnetic molecules synthesized to date, the icosidodecahedron with
antiferromagnetically coupled spins of s = 1/2. We show how genuine quantum features such as the
magnetization plateau behave as a function of temperature. 相似文献