Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article Citation - WoS: 29Citation - Scopus: 32Dark-Bright Optical Solitary Waves and Modulation Instability Analysis With (2+1)-Dimensional Cubic-Quintic Nonlinear Schrodinger Equation(Taylor & Francis Ltd, 2019) Aliyu, Aliyu Isa; Yusuf, Abdullahi; Baleanu, Dumitru; Inc, MustafaThis paper addresses the (2+1)-dimensional cubic-quintic nonlinear Schrodinger equation (CQNLS) that serves as the model to study the light propagation through nonlinear optical media and non-Kerr crystals. A dark-bright optical solitary wave solution of this equation is retrieved by adopting the complex envelope function ansatz. This type of solitary wave describes the properties of bright and dark optical solitary waves in the same expression. The integration naturally lead to a constraint condition placed on the solitary wave parameters which must hold for the solitary waves to exist. Additionally, the modulation instability (MI) analysis of the model is studied based on the standard linear stability analysis and the MI gain spectrum is got. Numerical simulation and physical interpretations of the obtained results are demonstrated. It is hoped that the results reported in this paper can enrich the nonlinear dynamical behaviors of the CQNLS.Article Citation - WoS: 3Citation - Scopus: 4Po and Ptd Approach To the Diffraction Problem by a Resistive Half-Plane(Taylor & Francis Ltd, 2014) Basdemir, Husnu DenizDiffracted fields from a resistive half-plane were investigated by the method of physical optics (PO) and the physical theory of diffraction. The coefficient of the PO scattering integral was derived for the first time for the resistive half-plane. Uniform fringe field expressions were obtained in terms of the Fresnel functions. The resultant expressions of the fringe fields were plotted and analyzed numerically.Article Citation - WoS: 1Citation - Scopus: 1On the Non-Commutative Neutrix Product of the Distributions X<sup>-r</Sup>+ Ln<sup>p</Sup> X+ and X<sup>μ</Sup>+ln<sup>q< X+(Taylor & Francis Ltd, 2006) Tas, Kenan; Fisher, BrianLet f and g be distributions and g(n) = (g*delta(n))(x), where delta(n)(x ) is a certain sequence converging to the Dirac delta-function. The non-commutative neutrix product f o g of f and g is defined to be the neutrix limit of the sequence {fg(n) }, provided its limit h exists in the sense that [GRAPHICS] for all functions phi in D. It is proved that (x(+)(-r) ln(p) x(+)) o (x(+)(mu) ln(q) x(+)) = x(+)(-r+mu) ln(p+q) x(+) (x(-)(-r) ln(p) (x)-) o (x(-)(mu) ln(q) x(-)) = x(-)(-r+mu) ln(p+q) x(-) for mu < r - 1;mu not equal 0, +/- 1, +/- 2,..., r = 1,2,..., and p, q = 0, 1, 2,....Article Citation - WoS: 8Citation - Scopus: 8Analysis of the Specific Heat and the Free Energy of [N(ch3)4]2znbr4 Close To the Ferro-Paraelastic Phase Transition(Taylor & Francis Ltd, 2019) Kiraci, A.A power-law formula deduced from the Ising model was used to analyze the temperature dependence of the specific heat and the Gibbs free energy of [N(CH3)(4)](2)ZnBr4 compound in the vicinity of the phase transition temperature of T-C = 287.2 K. Obtained values of the critical exponents from the Gibbs free energy were consistent with that predicted from 2-d potts model ( = 0.3), while obtained values of from the specific heat in both ferroelastic and paraelastic phases were consistent with that predicted from the mean field theory ( = 0) in the vicinity of the phase transition temperature. This is an indication of that [N(CH3)(4)](2)ZnBr4 compound undergoes a second order type phase transition. Also, the enthalpy () and the entropy () of this crystal were calculated in terms of the extracted values of the critical exponent in both ferroelastic and paraelastic phases.Conference Object Citation - WoS: 4Citation - Scopus: 4Order-Disorder Transition in the Ferroelectric Litao3(Taylor & Francis Ltd, 2019) Yurtseven, Hamit; Kiraci, AliThe temperature dependences of the damping constant and the relaxation time are calculated by using the Raman frequencies of a* and the lowest A(1) (TO) phonons in the ferroelectric phase close to the ferroelectric-paraelectric transition in LiTaO3 (T-C = 963 K). Both calculations are performed by considering the frequency as an order parameter for the pseudospin-phonon (PS) and the energy fluctuation (EF) models using the observed data from the literature. Values of the activation energies of this crystal are also deduced by using both models in this crystal. Our results show that the PS and EF models can describe the observed behavior adequately for the order-disorder transition in LiTaO3.Article Citation - WoS: 3Citation - Scopus: 4Damping Constant and the Inverse Relaxation Time Calculated as a Function of Pressure Using the X-Ray Diffraction Data Close To the Cubic-Tetragonal Phase Transition in Srtio3(Taylor & Francis Ltd, 2019) Kiraci, A.; Yurtseven, H.The damping constant is calculated as a function of pressure at room temperature using the normalized intensity as an order parameter near the cubic-tetragonal phase transition in SrTiO3. The observed X-ray diffraction data are used for the normalized intensities to calculate the damping constant () from the pseudospin-phonon (PS) coupled model and the energy fluctuation (EF) model, which is fitted to the observed FWHM data from the literature for comparison. Using the calculated values, the pressure dependence of the inverse relaxation time () is predicted close to the cubic-tetragonal phase transition in SrTiO3. Our calculated damping constant from both models explains the observed FWHM satisfactorily and our prediction of the inverse relaxation time can also be compared with the experimental measurements when they are available in the literature.Article Citation - WoS: 13Citation - Scopus: 13Field Correlation of Flat-Topped Beams in Anisotropic Non-Kolmogorov Turbulent Atmosphere(Taylor & Francis Ltd, 2019) Baykal, Yahya; Ata, YalcinField correlation of flat-topped beams in anisotropic non-Kolmogorov turbulent atmosphere is formulated and evaluated. Larger anisotropic factor causes higher field correlations. Smaller field correlations are seen when the transverse distance at the receiver plane increases. Smaller field correlations are observed at large off-axis transverse receiver points, which are valid for any anisotropic factor and for any power-law exponent of non-Kolmogorov turbulence. When the flat-topped beam is composed of large number of Gaussian beams, the field correlation becomes smaller. In anisotropic non-Kolmogorov turbulence, longer propagation distances, larger structure constants, smaller inner scales and smaller source sizes decrease the field correlation. Larger power law exponent of non-Kolmogorov turbulence increases the field correlations at any anisotropic factor.Article Citation - WoS: 7Citation - Scopus: 8A Novel Approach for Renovation of Current Social Housing Stock Based on Energy Consumption in Turkey: Significance of Occupant Behaviour(Taylor & Francis Ltd, 2019) Harputlugil, Timucin; Pedergnana, Matthieu; Sarioglu, Esra; Harputlugil, Guelsu UlukavakThe goal of this research is to attempt establishing occupant behaviour profiles and how that behaviour impacts energy consumption with regard to indoor comfort levels in the current social housing stock in Turkey. The data consists of a large statistical survey that included four housing complexes situated in different climate regions in Turkey. Another more detailed survey was given to occupants of housing blocks in Ankara. Apartments were also monitored during a one-week period in summer and again in winter. All collected data were evaluated by sensitivity analysis. The results showed that occupant presence at home and operating windows had the most profound effect on internal loads and comfort levels whole year. Additionally, the transparency level of curtains, impacts the indoor temperature during the winter time. The results were used to develop a web-based tool which is going to be a guide for renovation strategies of current housing stock.Article Citation - WoS: 8Citation - Scopus: 8Localization of Metallicity and Magnetic Properties of Graphene and of Graphene Nanoribbons Doped With Boron Clusters(Taylor & Francis Ltd, 2014) Kunstmann, Jens; Quandt, Alexander; Ozdogan, CemAs a possible way of modifying the intrinsic properties of graphene, we study the doping of graphene by embedded boron clusters with density functional theory. Cluster doping is technologically relevant as the cluster implantation technique can be readily applied to graphene. We find that B-7 clusters embedded into graphene and graphene nanoribbons are structurally stable and locally metallize the system. This is done both by the reduction of the Fermi energy and by the introduction of boron states near the Fermi level. A linear chain of boron clusters forms a metallic "wire" inside the graphene matrix. In a zigzag edge graphene nanoribbon, the cluster-related states tend to hybridize with the edge and bulk states. The magnetism in boron-doped graphene systems is generally very weak. The presence of boron clusters weakens the edge magnetism in zigzag edge graphene nanoribbon, rather than making the system appropriate for spintronics. Thus, the doping of graphene with the cluster implantation technique might be a viable technique to locally metallize graphene without destroying its attractive bulk properties.Article Citation - WoS: 3Citation - Scopus: 2Calculation of the Infrared Frequencies as a Function of Temperature Using the Volume Data in the Ferroelectric Phase of Nano2(Taylor & Francis Ltd, 2014) Kiraci, A.; Yurtseven, H.We calculate the temperature dependence of the infrared frequencies of the TO and LO modes with the symmetries of A(1), B-1 and B-2 mainly in the ferroelectric phase of NaNO2. This calculation is carried out using the volume dependence of the infrared frequencies through the mode Gruneisen parameter in this crystal. The volume dependences of the infrared frequencies are fitted to the observed frequencies by using constant mode Gruneisen parameter in the ferroelectric phase of NaNO2. Our results show that this method of calculating the infrared frequencies describes the observed behaviour of NaNO2 adequately.