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Articles 8731 - 8760 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Charged Particle--Image Interaction Near A Conducting Surface, Ersen Mete, Meti̇n Durgut
Charged Particle--Image Interaction Near A Conducting Surface, Ersen Mete, Meti̇n Durgut
Turkish Journal of Physics
The interaction of a bulk electron with conducting surfaces is studied by means of the Bohm-Pines transformation in the second quantization formalism. The effective interaction potentials are obtained for the case of one plane and two plane configurations in the form of electron-image electron scattering.
Large Amplitude Wave Trains In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Large Amplitude Wave Trains In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Turkish Journal of Physics
Using ground-based neutron monitor data of Deep River, the high amplitude anisotropic wave train events (HAE) in cosmic ray intensity have been investigated during the period 1991--1994. It has been observed that the phase of diurnal anisotropy for majority of HAE cases remains in the same co-rotational direction, whereas for some HAE cases the phase of diurnal anisotropy has shifted to later hours. For the majority of HAE cases the amplitude of semi-diurnal anisotropy remains statistically the same, whereas the phase of semi-diurnal anisotropy for all HAE cases has shifted to later hours. Furthermore, for tri-diurnal anisotropy the phase shifts …
Structural And Magnetic Properties Of Co_{0.6}Znn_{0.4}Mn_{X}Fe_{2 - X}O_{4}, O.M. Hemeda
Structural And Magnetic Properties Of Co_{0.6}Znn_{0.4}Mn_{X}Fe_{2 - X}O_{4}, O.M. Hemeda
Turkish Journal of Physics
A series of Co-Zn ferrite samples substituted by Mn were prepared by the usual double sintering ceramic technique. The x-ray diffraction patterns of the samples confirmed the formation of single-phase spinel structure, and x-ray analysis supply data that suggests the cation distribution of the material. The tetrahedral and octahedral radius permits one to calculate the theoretical lattice parameter and the bond lengths Fe-O at A and B sites. The particle size of the given samples was measured from the Scherer equation and a correlation was found between particle size, and structural and magnetic properties. The XRF confirmed the presence of …
The Normal And Inverted Meyer-Neldel Rule In The Ac Conductivity, Fouad Abdel-Wahab
The Normal And Inverted Meyer-Neldel Rule In The Ac Conductivity, Fouad Abdel-Wahab
Turkish Journal of Physics
Recently, a new approach has been proposed for the correlated barrier hopping (CBH) model where the ac relaxation time is thought to obey the Meyer-Neldel (MN) rule. This approach gives quantitative agreement with some reliable published experimental data. We report on an experiment involving the characterization of the ac conductivity of Se-Te thin films over a wide range of frequencies and temperatures, carried out in order to confirm applicability of the MN rule to the ac conductivity. In addition to the normal MN rule, the inverted MN rule was observed.
Design And Preparation Of Antireflection And Reflection Optical Coatings, Özlem Duyar, H. Zafer Durusoy
Design And Preparation Of Antireflection And Reflection Optical Coatings, Özlem Duyar, H. Zafer Durusoy
Turkish Journal of Physics
In this study, reflective and antireflective coatings were designed and simulated. Optical transmission and reflection values were deduced with a matrix formulation via a personal computer. It was found that the number of layers affects the optical performance. The width of the high-reflectance region in the reflectance curves decreases, while its height increases with the increasing number of layers for the reflective coating design. The antireflection coatings transmit about 99.89% in a broad high-pass band at the central wavelength of \lambda_{0} = 450 nm. In addition, simulated Fabry-Perot filters result in a single sharp transmittance peak at the desired central …
The Riemann Zeta Function Applied On Glassy Systems And Neural Networks, Viorel L. Cartas
The Riemann Zeta Function Applied On Glassy Systems And Neural Networks, Viorel L. Cartas
Turkish Journal of Physics
Glassy systems and Neural networks share a simple model of study: the model of a set of N non interacting harmonic oscillators with energy. In this paper the author tries to describe these complex systems in order to find the energy involved. The mathematical method used is described in detail.
Exceptionaly Low Amplitude Anisotropic Wave Train Events In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Exceptionaly Low Amplitude Anisotropic Wave Train Events In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Turkish Journal of Physics
The unusually low amplitude anisotropic wave train events (LAEs) in cosmic ray intensity using the ground-based Deep River neutron monitor data has been studied during the period 1991--94. It has been observed that the phase of the diurnal anisotropy for majority of the LAE events remains in the corotational direction. However, for some of the LAE events the phase of the diurnal anisotropy shifts towards earlier hours. On the other hand, the amplitude of the semi-diurnal anisotropy remains statistically the same whereas, phase shift towards later hours; similar trend has also been found in case of tri-diurnal anisotropy. The interplanetary …
On Hamiltonian Formulation Of Non-Conservative Systems, Eqab M. Rabei, Tareq S. Alhalholy, A. A. Taani
On Hamiltonian Formulation Of Non-Conservative Systems, Eqab M. Rabei, Tareq S. Alhalholy, A. A. Taani
Turkish Journal of Physics
Fractional derivatives are used to construct the Lagrangian and the Hamiltonian formulation for non-conservative systems. To clarify the theory of Riewe two interesting examples are given. The potentials are obtained using the Laplace transform operator for fractional derivatives and the Lagrangian and Hamiltonian formulations are constructed for the two systems. Besides, it is shown that the Hamilton equations of motion are in agreement with the Euler-Lagrange equations for these systems.
Self Ionization Probabilities Following De-Excitation Decay Of K-Shell Vacancy In Atoms Z = 10--80, Adel M. El-Shemi
Self Ionization Probabilities Following De-Excitation Decay Of K-Shell Vacancy In Atoms Z = 10--80, Adel M. El-Shemi
Turkish Journal of Physics
The average number of ejected electrons and the probability of ion charge state distributions following K-shell ionization in atoms from Z = 10 to Z = 80 were calculated. Monte Carlo simulation technique was used to simulate all possible pathways of radiative and non-radiative transitions to fill the inner-shell ionization in excited atoms. The radiative and non-radiative branching ratios were calculated from Multiconfiguration Dirac-Fock (MCDF) and Dirac-Fock-Slater (DFS) wave functions. The average number of ejected electrons in atoms with Z = 10 is about two, because the non-radiative transitions exceed radiative transitions by 98\%. The mean number of ejected electrons …
Comparative Study Of First Two Harmonics In Cosmic Ray Intensity For The Period 1964-95, Rekha Agarwal Mishra, Rajesh K. Mishra
Comparative Study Of First Two Harmonics In Cosmic Ray Intensity For The Period 1964-95, Rekha Agarwal Mishra, Rajesh K. Mishra
Turkish Journal of Physics
The Deep River neutron monitor data has been harmonically analyzed for the period 1964--95 covering three solar cycles 20, 21 and 22, looking for a long term trend of the diurnal and semi-diurnal anisotropies of cosmic ray intensity on geomagnetically 60 quiet days. The amplitude of both the harmonics remains statistically constant during 1964-70. The amplitudes of the first harmonic is found to be low during 1965, 1967, 1976-77, 1986-87, 1991, 1993 and 1995. The amplitude of diurnal anisotropy acquired exceptionally large values in 1985, whereas semi-diurnal anisotropy acquired large values in 1974-75 and in 1984, which coincided with epochs …
Determination Of The Rotational Constant A_0 And The Bending Angle Cnc For Ch_3 Nc And Ch_3 ^{15}Nc Molecules, Mohammad Al-Share
Determination Of The Rotational Constant A_0 And The Bending Angle Cnc For Ch_3 Nc And Ch_3 ^{15}Nc Molecules, Mohammad Al-Share
Turkish Journal of Physics
The rotational constant A_0 for the ground state of CH_3 NC and CH_3 ^{15}NC isotopomers is calculated using a technique which was used earlier for CH_3CCH [9], CH_3CN [10] and SiH_3CCH [11]. This technique is based on calculating the moment of inertia tensors in the bent configuration due to the \nu_8 vibrational state, which is associated with the CNC bending vibration. These values of the moments of inertia are fitted with the values calculated from the rotational constant B_V, found experimentally by measuring the rotational frequencies in the microwave and infrared regions. From the fitting, the rotational constant A_0, the …
A Novel Radiative Substrate Heater, Abdullah Ceylan, Erdal Kaynak, Şadan Özcan, Tezer Firat
A Novel Radiative Substrate Heater, Abdullah Ceylan, Erdal Kaynak, Şadan Özcan, Tezer Firat
Turkish Journal of Physics
In this work, we have developed a new low cost radiative substrate heater for deposition of high-T_c superconducting thin films. It has all the features required for the preparation of high quality superconducting thin films. It is possible to reach ~ 800 °C substrate temperature with it by using only one 250 W halogen projector bulb.
Effect Of Development Time On Polymer Phase Separation In A Pmma Resist, Mohammad Naeem Khalid, Shazia Yasin, Mohammad Riaz Khan
Effect Of Development Time On Polymer Phase Separation In A Pmma Resist, Mohammad Naeem Khalid, Shazia Yasin, Mohammad Riaz Khan
Turkish Journal of Physics
Developer composition type and development technique are known to influence surface and edge roughness in polymethylemethacrylate (PMMA); and it is during development, we believe, that the result is most influenced by the phase separation into polymer-rich and polymer-poor regions. This polymer phase separation is more prominent in a weaker developer and low temperature. In this paper, we investigate the effect of development time on the extent of polymer phase separation in an exposed PMMA developed in a standard developer i.e. 1:3 MIBK:IPA at 20 °C and rinsed in pure IPA for 30 sec. The polymer phase separation is found to …
The Zero Position Of The Forward-Backward Asymmetry In The B \Rightarrow K\Ell^+\Ell^- Decay With New Physics Effects, Altuğ Arda
Turkish Journal of Physics
Using the most general model-independent effective Hamiltonian comprising local four-Fermi operators (scalar, vector, and tensor operators), we study the sensitivity of the zero position of the lepton asymmetry to the new operators beyond the Standard Model (SM) in the B \rightarrow K\ell^+\ell^- decay. It is found that among all operators, only the scalar and tensor operators contribute to the forward-backward asymmetry, in which case the forward-backward asymmetry has a non-vanishing value.
Physical Characteristics Of Polymer Magnetic Microspheres, Rasim A. Ali-Zade
Physical Characteristics Of Polymer Magnetic Microspheres, Rasim A. Ali-Zade
Turkish Journal of Physics
In this study the structure and the magnetic properties of polymer microspheres, filled with magnetite nanoparticles are investigated. Average particle size of magnetite nanoparticles before and after being introduced into polymer microspheres, and the distance between nanoparticles in the polymer microspheres, are measured. Magnetization curve of polymer magnetic microspheres (PMMS) is determined. The magnetic susceptibility of PMMS with various diameters, and the dependence of PMMS magnetic susceptibility on diameter are determined. Magnetization occurs due to the orientation of PMMS as a magnetic moment. The total magnetic moment of PMMS is the sum of magnetic moments of PMMS sections which consist …
Simulation Of Millimeter-Wave Gunn Oscillations In Gallium Nitride, Cem Sevi̇k, Ceyhun Bulutay
Simulation Of Millimeter-Wave Gunn Oscillations In Gallium Nitride, Cem Sevi̇k, Ceyhun Bulutay
Turkish Journal of Physics
High field transport in wide bandgap semiconductors like GaN is of great technological importance. The negative differential mobility regime at high fields, under suitable conditions, can lead to millimeter-wave Gunn oscillations. Using extensive simulation based an ensemble Monte Carlo technique, the prospects of GaN Gunn diodes are theoretically investigated. The possibility of operating these Gunn diodes at their higher harmonic modes are explored. The main finding of this research is that the carrier dynamics in GaN can be tailored by an optimum choice of doping profile, temperature and bias conditions so that the efficiency of higher harmonic Gunn oscillations can …
Structural Characterization And Magnetization Of Mg_{0.5}Cu_{0.5}Y_{X}Fe_{2-X}O_4 Ferrites, Mansour Al-Haj
Structural Characterization And Magnetization Of Mg_{0.5}Cu_{0.5}Y_{X}Fe_{2-X}O_4 Ferrites, Mansour Al-Haj
Turkish Journal of Physics
Mg_{0.5}Cu_{0.5}Y_xFe_{2-x}O_4 ferrites were prepared by the solid state reaction method and were characterized by X-ray diffraction and magnetization measurements. A single spinel phase was obtained in the range 0 \le x \le 0.08. The lattice parameter was found to increase with the increase of x except at x = 0.08, which may indicate a distortion in the spinel lattice. The saturation magnetization was found to decrease with increasing x due to replacement of the magnetic Fe^{3+} ions by the nonmagnetic Y^{3+} ions.
Calorimetric Studies Of The Crystallization Growth Process In Glassy Se_{70}Te_{30-X}Ag_X Alloys, N. Mehta, D. Kumar, A. Kumar
Calorimetric Studies Of The Crystallization Growth Process In Glassy Se_{70}Te_{30-X}Ag_X Alloys, N. Mehta, D. Kumar, A. Kumar
Turkish Journal of Physics
Differential Scanning Calorimetry (DSC) is performed at different heating rates under non-isothermal conditions to study the crystallization kinetics of Se_{.70}Te_{.26}Ag_{.04} and Se_{.70}Te_{.24}Ag_{.06} chalcogenide glasses in terms of the activation energy of nucleation and growth process. To understand the nucleation and growth process, the values of the growth morphology parameter n and the numerical factor m of crystallization mechanism have been evaluated using different non--isothermal methods. The values of n and m have been found to be nearly equal, indicating that the present glasses have sufficient nuclei before DSC experiment and the activation energy for nucleation process E_N is zero. Hence, …
Cyclotron Resonant Heating And Acceleration Of Protons, O Vi & Mg X Ions In The North Polar Coronal Hole, E. Rennan Pekünlü, Kadri̇ Yakut, Hi̇cran Şart
Cyclotron Resonant Heating And Acceleration Of Protons, O Vi & Mg X Ions In The North Polar Coronal Hole, E. Rennan Pekünlü, Kadri̇ Yakut, Hi̇cran Şart
Turkish Journal of Physics
Ultraviolet Coronograph Spectrometer aboard Solar and Heliospheric Observatory (SOHO) has revealed the existence of temperature anisotropy of many minor ion species that populate the north solar polar coronal hole. In this study, we examined the propagation characteristics of ion-cyclotron waves which resonate with protons, O VI and Mg X ions. In our empirical model, radial variation of the magnetic field, electron and ion number densities, perpendicular and parallel temperature of protons, O VI and Mg X ions are adopted from the measurements of various instruments aboard SOHO. Since most of the measurements of SOHO instruments begin at 1.5 R (=r/R_{\odot}) …
Formation Of The Monolithic Silica Gel Column With Bimodal Pore Structure, Wenhui Gao, Gegliang Yang, Jing Yang, Haiyan Liu
Formation Of The Monolithic Silica Gel Column With Bimodal Pore Structure, Wenhui Gao, Gegliang Yang, Jing Yang, Haiyan Liu
Turkish Journal of Chemistry
A biporous monolithic silica gel column possessing both micrometer sized through-pores and nanometer sized mesopores located in the silica skeletons was prepared and the high concentration porogen (e.g., 2 mol/L ammonium hydroxide solution) was use for increasing mesopore size in this work. The mechanism for the preparation of the monolithic column was investigated in detail. Moreover, the effect of the polyethylene glycol concentration in the starting solution was studied and it was found that a lower concentration range was also suitable for forming the interconnected porous structure for the monolithic silica gel column. At lower concentrations, however, the phase separation …
The Theory Of Jacobi Systems And Their Abelian Representations, M. Shahryari, Y. Zamani
The Theory Of Jacobi Systems And Their Abelian Representations, M. Shahryari, Y. Zamani
Turkish Journal of Mathematics
In this article we introduce a new generalization of the concept of Lie ring which we call Jacobi system and we investigate some elementary properties of these systems and their Abelian representations.
Modules Supplemented Relative To A Torsion Theory, M. Tamer Koşan, Abdullah Harmanci
Modules Supplemented Relative To A Torsion Theory, M. Tamer Koşan, Abdullah Harmanci
Turkish Journal of Mathematics
This article introduces the concept of a \tau-supplemented module as follows: Given a hereditary torsion theory in Mod R with associated torsion functor \tau, we say that a module M is \tau-supplemented when for every submodule N of M there exists a direct summand K of M such that K\leq N and N/K is \tau-torsion module. We present here some fundamental properties of this class of modules and study the decompositions of \tau-supplemented modules under certain conditions on modules. The question of which direct sum of \tau-supplemented R-modules are \tau-supplemented is treated here.
On Orthogonal Generalized Derivations Of Semiprime Rings, Nurcan Argaç, Atsushi Nakajima, Emi̇ne Albaş
On Orthogonal Generalized Derivations Of Semiprime Rings, Nurcan Argaç, Atsushi Nakajima, Emi̇ne Albaş
Turkish Journal of Mathematics
In this paper, we present some results concerning two generalized derivations on a semiprime ring. These results are a generalization of results of M. Bre\u{s}ar and J. Vukman in [2], which are related to a theorem of E. Posner for the product of derivations on a prime ring.
Conjugacy Classes Of Finite Subgroups Of Certain Mapping Class Groups, Michal Stukow
Conjugacy Classes Of Finite Subgroups Of Certain Mapping Class Groups, Michal Stukow
Turkish Journal of Mathematics
We give a complete description of conjugacy classes of finite subgroups of the mapping class group of the sphere with r marked points. As a corollary we obtain a description of conjugacy classes of maximal finite subgroups of the hyperelliptic mapping class group. In particular, we prove that, for a fixed genus g, there are at most five such classes.
On \Theta-Euclidean L-Fuzzy Ideals Of Rings, Ayten Koç, Erol Balkanay
On \Theta-Euclidean L-Fuzzy Ideals Of Rings, Ayten Koç, Erol Balkanay
Turkish Journal of Mathematics
In this paper we define a \theta-Euclidean level subset and a \theta-Euclidean level ideal. We also give some properties of a \theta-Euclidean level subset.
New Special Curves And Developable Surfaces, Shyuichi Izumiya, Nobuko Takeuchi
New Special Curves And Developable Surfaces, Shyuichi Izumiya, Nobuko Takeuchi
Turkish Journal of Mathematics
We define new special curves in Euclidean 3-space which we call slant helices and conical geodesic curves. Those notions are generalizations of the notion of cylindrical helices. One of the results in this paper gives a classification of special developable surfaces under the condition of the existence of such a special curve as a geodesic. As a result, we consider geometric invariants of space curves. By using these invariants, we can estimate the order of contact with those special curves for general space curves. All arguments in this paper are straight forward and classical. However, there have been no papers …
Groups With Rank Restrictions On Non-Subnormal Subgroups, Leonid Andreevich Kurdachenko, Howard Smith
Groups With Rank Restrictions On Non-Subnormal Subgroups, Leonid Andreevich Kurdachenko, Howard Smith
Turkish Journal of Mathematics
Let G be a group in which every non-subnormal subgroup has finite rank. This paper considers the question as to which extra conditions on such a group G ensure that G has all subgroups subnormal. For example, if G is torsion-free and locally soluble-by-finite then either G has finite 0-rank or G is nilpotent. Several results are obtained on soluble (respectively, locally soluble-by-finite) groups satisfying the stated hypothesis on subgroups.
Ideal Theory In Topological Algebras, A. Najmi
Ideal Theory In Topological Algebras, A. Najmi
Turkish Journal of Mathematics
Given a simplicial topologically non radical algebra A, we characterize its topological radical, radA. If furthermore A is advertive, then radA coincides with the Jacobson radical RadA. On the other hand, it is shown that every two-sided invertive simplicial topological Gelfand-Mazur algebra has a functional spectrum and for every topologically nonradical simplicial Gelfand-Mazur amits the set \mathcal{X}(A), of all continuous multiplicative linear functionals, is not empty.
On A Certain Class Of Bessel Integrals, Ali A. Al-Jarrah, A. Al-Momani
On A Certain Class Of Bessel Integrals, Ali A. Al-Jarrah, A. Al-Momani
Turkish Journal of Mathematics
There are many old results of integrals involving Bessel functions, currently available in handbooks, but we found no recourse in the well-known references to how they were established. In this paper, we attempt to have a clear way of proving some of these results. In fact, we consider a certain class of Bessel integrals where we prove that such integrals vanish under certain conditions. To this end some theorems regarding this class of integrals with their proofs are put forward. A computer algorithm is provided to implement some of our results. The result in this paper extend the work in …
Neural Analysis Of Top Shielded Multilayered Coplanar Waveguides, Mustafa Türkmen, Celal Yildiz, Şeref Sağiroğlu
Neural Analysis Of Top Shielded Multilayered Coplanar Waveguides, Mustafa Türkmen, Celal Yildiz, Şeref Sağiroğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Artificial neural networks (ANNs) have been promising tools for many applications. In recent years, a computer-aided design approach based on (ANNs) has been introduced to microwave modelling, simulation and optimization. In this work, the characteristic parameters of top shielded multilayered coplanar waveguides (CPWs) have been determined with the use of ANN models. These neural models were trained with Levenberg-Marquardt, resilient propagation, Bayesian regulation, quasi-Newton, and backpropagation learning algorithms. Better performance and learning speed with a simpler structure were achieved from these models. The results have shown that the estimated characteristic parameters are in very good agreement with the computed results …