MAKALE
http://hdl.handle.net/11552/7
2018-01-09T08:31:59ZPrediction of femtosecond oscillations in the transient current of a quantum dot in the Kondo regime
http://hdl.handle.net/11552/972
Prediction of femtosecond oscillations in the transient current of a quantum dot in the Kondo regime
Goker, A; Zhu, Z. Y.; Manchon, A.; Schwingenschlogl, U.
We invoke the time-dependent noncrossing approximation in order to study the effects of the density of states of gold contacts on the instantaneous conductance of a single electron transistor which is abruptly moved into the Kondo regime by means of a gate voltage. For an asymmetrically coupled system, we observe that the instantaneous conductance in the Kondo time scale exhibits beating with distinct frequencies, which are proportional to the separation between the Fermi level and the sharp features in the density of states of gold. Increasing the ambient temperature or bias quenches the amplitude of the oscillations. We attribute the oscillations to interference between the emerging Kondo resonance and van-Hove singularities in the density of state. In addition, we propose an experimental realization of this model.
2015-10-06T00:00:00ZFinite Type Curve IN 3-Dimensional Sasakian Manifold
http://hdl.handle.net/11552/971
Finite Type Curve IN 3-Dimensional Sasakian Manifold
Camci, Cetin; Hacisalihoglu, H. Hilmi
We study finite type curve in R(3)(-3) which lies in a cylinder N(2)(c). Baikousis and Blair proved that a Legendre curve in R(3)(-3) of constant curvature lies in cylinder N(2)(c) and is a 1-type curve, conversely, a 1-type Legendre curve is of constant curvature. In this paper, we will prove that a 1-type curve lying in a cylinder N(2)(c) has a constant curvature. Furthermore we will prove that a curve in R(3)(-3) which lies in a cylinder N(2)(c) is finite type if and only if the curve is 1-type.
2015-10-06T00:00:00ZThe Spectral, Structral and Thermal Characterizations of Dimethyl Sulphoxide, Pyridine, Ethanolamine and N-Methyl Formamide Intercalated Kaolinites
http://hdl.handle.net/11552/970
The Spectral, Structral and Thermal Characterizations of Dimethyl Sulphoxide, Pyridine, Ethanolamine and N-Methyl Formamide Intercalated Kaolinites
Caglar, Bulent; Afsin, Beytullah; Eren, Erdal; Tabak, Ahmet; Cirak, Cagri; Cubuk, Osman
The intercalation of dimethyl sulphoxide (DMSO), pyridine (Py), ethanolamine (Ea), and N-methyl formamide (NMF) molecules into the kaolinite interlayers led to an appreciable decrease of 3697 cm(-1) of the hydroxyl band. The appearance of the peaks at 3662, 3541, and 3504 cm(-1) proved that the DMSO species are intercalated between the kaolinite layers through forming H-bonds with internal-surface hydroxyl groups. The intensities of the 942 and 796 cm(-1) bending peaks arising from inner-surface hydroxyls decreased and new vibrational features appeared due to the intercalation of the guest species. The d(001) value of pure kaolinite was found at 7.18 angstrom, and the d(001) values were seen at 11.26, I 1.62, 10.77, and 10.67 angstrom for kaolinite-dimethyl sulphoxide (K-DMSO), kaolinite-pyridine (K-Py), kaolinite-ethanolamine (K-EA), and kaolinite-N-methyl formamide (K-NMF) composites, respectively. The endothermic differential thermal analysis (DTA) peaks at a temperature of 108-334 degrees C reflected the changes in the physicochemical properties of the intercalated species. The thermal stability increase followed the order of K-Py < K-NMF < K-Ea < K-DMSO. Based on the thermal analysis data, the intercalation ratios of the composites above were determined as 80.0, 40.0, 81.6, and 82.0%, respectively. The specific surface areas are affected by the intercalation geometry of the composites within the gallery spacing. The surface areas of the K-DMSO, K-Py, and K-EA complexes increased whereas the surface area of K-NMF decreased with respect to that of untreated kaolinite.
2015-10-06T00:00:00ZEquilibrium and thermodynamic studies of Cu(II) removal by iron oxide modified sepiolite
http://hdl.handle.net/11552/969
Equilibrium and thermodynamic studies of Cu(II) removal by iron oxide modified sepiolite
Eren, E.; Gumus, H.; Ozbay, N.
This paper presents the adsorption of Cu(II) from aqueous solution by raw sepiolite (RS) and iron oxide-coated sepiolite (ICS) samples. Adsorption of Cu(II) by sepiolite samples was investigated as a function of the initial Cu(II) concentration, solution pH, ionic strength, temperature and the presence of an inorganic ligand (Cl−, SO42− and HPO42−). Changes in the surface and structure were characterized by means of XRD, IR and XRF techniques. The Langmuir monolayer adsorption capacities of RS and ICS in 0.1 M NaNO3 solution at 298 K were estimated to be 14.96 and 21.56 mg/g, respectively. ΔG, ΔH and ΔS were evaluated for RS and ICS to be −14.14 kJ/mol (at 298 K), 39.03 kJ/mol and 178 J/mol K, and −16.09 kJ/mol (at 298 K), 32.99 kJ/mol and 165 J/mol K, respectively.
2015-10-06T00:00:00Z