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Articles 9511 - 9540 of 10317
Full-Text Articles in Physical Sciences and Mathematics
Generalized 2d Yang-Mills Theories: Large-N Limit And Phase Structure, Masoud Alimohammadi
Generalized 2d Yang-Mills Theories: Large-N Limit And Phase Structure, Masoud Alimohammadi
Turkish Journal of Physics
After review the 2D Yang--Mills theories (YM$_2$) and its large--$N$ behaviour, the Generalized 2D Yang--Mills theories (gYM$_2$) and their partition functions on a general two--dimensional Riemann surface are discussed.The large--$N$ behaviour of these models is studied in weak regime, and in strong regime, we restrict ourselves to $\phi^4$ gYM$_2$. We show that this model has a third order phase transition, similar to ordinary YM$_2$ theory.
Spinors And Positive Mass, Malcolm Ludvigsen
Spinors And Positive Mass, Malcolm Ludvigsen
Turkish Journal of Physics
As an example of how spinor methods can be applied to the positive-mass theorem, a simple, spinor-based proof of the theorem is presented for the case of a single black hole. Generalisations of the theorem are also discussed.
The Decay Of A Black Hole As A Quantum Dissipative Process, Carl Wolf
The Decay Of A Black Hole As A Quantum Dissipative Process, Carl Wolf
Turkish Journal of Physics
By considering the decay of a black hole as a result of the interaction of a quantum system with a dissipative vacuum, or in terms of string theory, the interaction of localized string modes with non-local string modes, we demonstrate how the single parameter representing dissipation can be calculated in terms of known fundamental constants. In view of the uncertainty embodied in all the present theories of black hole decay it is suggested that the approach of this note might provide fresh insight to the problem of black hole decay. P.A.C.S.: 98.80-Dr Cosmology
The Effect Of Various Experimental Parameters On Glow Peaks And Trapping Parameters Of Caf_2:Dy (Tld-200) Crystals, A. Necmeddi̇n Yazici, M. Yakup Hacii̇brahi̇moğlu, Meti̇n Bedi̇r
The Effect Of Various Experimental Parameters On Glow Peaks And Trapping Parameters Of Caf_2:Dy (Tld-200) Crystals, A. Necmeddi̇n Yazici, M. Yakup Hacii̇brahi̇moğlu, Meti̇n Bedi̇r
Turkish Journal of Physics
In the present study, thermoluminescence glow curves of CaF$_{2}$:Dy (TLD-200) crystals have been investigated in detail between the temperature region 300-550 K. The number of peaks and their trapping parameters (E, s and b) have been determined using the computerized glow curve fitting, peak shape and isothermal decay methods. In addition, the effect of storage times at room temperature, dose levels and heating rates on the trapping parameters have been investigated in detail by using computerized glow curve deconvolution method (CGCD) using first and general order kinetic equations.
Effects Of Disorder On The Drag Rate In Double Quantum-Wire Systems, B. Tanatar
Effects Of Disorder On The Drag Rate In Double Quantum-Wire Systems, B. Tanatar
Turkish Journal of Physics
We study the Coulomb drag rate for electrons in a double quantum-wire structure in the presence of disorder. We use the particle number-conserving relaxation-time approximation to phenomenologically broaden the response functions entering the drag rate expression to account for the disorder effects. In contrast to the usual low-temperature regime investigated by various researchers, we focus our attention on the high-temperature drag rate to which plasmon modes are known to make substantial contribution. The full wave vector and frequency dependent random-phase approximation (RPA) at finite temperature and disorder strength is employed to describe the effective interlayer Coulomb interaction. The interplay between …
Steady States Of Dynamically Coupled Two-Species Systems, Muntasi̇r Barma, Sri̇ram Ramaswamy
Steady States Of Dynamically Coupled Two-Species Systems, Muntasi̇r Barma, Sri̇ram Ramaswamy
Turkish Journal of Physics
We study the steady states of two stochastic lattice models with two species of particles, where the local mobility of one species depends on the spatial distribution of the other. The eigenvalues of a $2\times 2$ matrix of couplings can develop imaginary parts, and the question arises whether this implies an instability to a macroscopically different steady state. In the first model, where the mobility depends on the local density of the other species, we show that the system undergoes macroscopic phase separation. In the second model, where the mobility depends on the second derivative of the density of the …
Global Results In Space Of Inter-Monomer Interactions For Hp Lattice Model, M. R. Ejtehadi̇, V. Shahrezaei̇, N. Hamedani̇
Global Results In Space Of Inter-Monomer Interactions For Hp Lattice Model, M. R. Ejtehadi̇, V. Shahrezaei̇, N. Hamedani̇
Turkish Journal of Physics
Using the ground state candidates for Hydrophobic-Polar lattice model on a two dimensional square lattice, we exactly enumerate the native states of proteins with length up to 20 for a wide range of energy parameters. We find the reduced set of contact maps, ground state candidates, perfectly stable sequences and designability of configurations.
Chaos In Closed Isotropic Cosmological Models With Steep Scalar Field Potential, A. V. Toporensky
Chaos In Closed Isotropic Cosmological Models With Steep Scalar Field Potential, A. V. Toporensky
Turkish Journal of Physics
The dynamics of closed scalar field FRW cosmological models is studied for several types of exponentially and more than exponentially steep potentials. The parameters of scalar field potentials which allow a chaotic behaviour are found from numerical investigations. It is argued that analytical studies of equation of motion at the Euclidean boundary can provide an important information about the properties of chaotic dynamics. Several types of transition from chaotic to regular dynamics are described.
Thermal Stability Of Fe_{85.5}B_{14.5} Metallic Glass, Asghari Maqsood, Ashfaq Ahmad
Thermal Stability Of Fe_{85.5}B_{14.5} Metallic Glass, Asghari Maqsood, Ashfaq Ahmad
Turkish Journal of Physics
The thermal stability and crystallization behaviour of metallic glass Fe\( _{85.5} \)B\( _{14.5} \) were investigated by Dynamic Temperature Resistivity Measurement (DTRM) technique from room temperature to 1050K in forward and reverse mode at a heating rate of 40 K/hr. The slope of Resistivity-Temperature-Curve (RTC) changes sign and magnitude at the temperature where the transition takes place. Differential Thermal Analysis (DTA) was carried out at the heating rates of 10, 20, 30 \& 40 K/min. A comparison of the results of DTRM and DTA measurements shows that crystallization in this alloy is two-stage process. Activation energy for two crystallization steps …
The Magnetic Super-Exchange Coupling In Copper(Ii) Acetate Monohydrate And A Redetermination Of The Crystal Structure, Ayhan Elmali
The Magnetic Super-Exchange Coupling In Copper(Ii) Acetate Monohydrate And A Redetermination Of The Crystal Structure, Ayhan Elmali
Turkish Journal of Physics
The magnetic properties and redetermination of crystal structure of copper(II) acetate monohydrate have been studied. The copper(II) centers are separated by 2.617(1) \AA \ and antiferromagnetically coupled (-2J = 292.2 cm$^{-1}$), which follows from temperature-dependent magnetic susceptibility measurements in the temperature range 4.2 to 300 K. The magnetic moment at 300 K is about 2.1 Bohr magnetons while 0.1 Bohr magnetons at 4.2 K. The magnetic susceptibility is at a maximum near 250 K and decreases rapidly as the temperature is lowered to liquid helium temperature.
Antiferromagnetic Transition In \Alpha-Mn-Fe System, R. K. Nkum, F. Boakye
Antiferromagnetic Transition In \Alpha-Mn-Fe System, R. K. Nkum, F. Boakye
Turkish Journal of Physics
Antiferromagnetic transition in $\alpha$-Mn-Fe alloys has been studied using resistivity-temperature measurements from 300 to 1.5 K. The results indicate that the transition temperature $T_N$ of the samples studied increases with increasing Fe concentration. This suggests that the N\'{e}el temperature is affected by Fe. Also, Fe plays a significant role in the local disorder on the magnetic moment of the ions in the complex manganese structure.
Synthesis And Characteristics Of Nickel Manganite By Lithiation, S. V. Salvi, M. R. Parab
Synthesis And Characteristics Of Nickel Manganite By Lithiation, S. V. Salvi, M. R. Parab
Turkish Journal of Physics
Spinel nickel manganite has been synthesized using ceramic technique, from (2MnO$_{2}$+NiO) mixture reduced using LiAlH$_{4}$. Powder X-ray diffractometry (XRD) indicates the formation of cubic spinel (a=8.33 A^o), while IR absorption spectral features are rather broad, though similar to those of spinel. The d.c. electrical conductivity of the ceramic is much smaller than that reported for NiMn$_{2}$O$_{4}$. Even though the band gap remains the same, when the sintering temperature is increased from 950^oC to 1100 ^oC, all other changes are insignificant except that the porosity and particle size nearly halve. The characteristics of the system are discussed in terms of `lithiation'.
Devitrification Of Volcanic Glasses In Konya Volcanic Units, Turkey, Zehra Karakaş, Selahatti̇n Kadi̇r
Devitrification Of Volcanic Glasses In Konya Volcanic Units, Turkey, Zehra Karakaş, Selahatti̇n Kadi̇r
Turkish Journal of Earth Sciences
The study area is composed of volcanic, sedimentary and volcano-sedimentary units, which are exposed south and southwest of the city of Konya. XRD analysis indicates that the volcanic units contain halloysite, kaolinite, smectite, illite and sepiolite type clay minerals and opal-CT, feldspar, quartz, minamiite and jarosite type non-clay minerals. SEM studies show that volcanic glasses, which are the main component of the volcanic units, appeared as curviplanar, vesicular-planar and in highly fractured shapes. Fractures and dissolution voids of the volcanic glasses are generally filled by hexagonal kaolinite, fibrous halloysite and smectite. Mineralogical and micromorphological observations indicate that clay minerals were …
The Absorption Properties Of P-Type Tlin_X Ga_{(1-X)} Se_2 And Tlgase_2, Beki̇r Gürbulak, Muhammet Yildirim, Aytunç Ateş, Sebahatti̇n Tüzemen, Yahya Kemal Yoğurtçu
The Absorption Properties Of P-Type Tlin_X Ga_{(1-X)} Se_2 And Tlgase_2, Beki̇r Gürbulak, Muhammet Yildirim, Aytunç Ateş, Sebahatti̇n Tüzemen, Yahya Kemal Yoğurtçu
Turkish Journal of Physics
$p-TlGaSe_2$, $p-TlIn_{0.3}Ga_{0.7}Se_2$ and $p-TlIn_{0.5}Ga_{0.5}Se_2$ single crystals were grown by the modified Bridgman-Stockbarger method in our crystal growth laboratory. The absorption measurements were carried out on $p-TlIn_xGa_{(1-x)}Se_2$ samples in temperature range 10-300 K in steps of 10 K. The binding energies of $p-TlGaSe_2$, $p-TlIn_{0.3}Ga_{0.7}Se_2$ and $p-TlIn_{0.5} Ga_{0.5}$ $Se_2$ were obtained as \\ 35.0 meV, 16.5 meV and 14.5 meV, respectively. THe direct band gaps were calculated as 2.244 eV, 2.195 eV, 2.164 eV in $p-TlGaSe_2$, 2.158 eV, 2.131 eV, 2.098 eV in $p-TlIn_{0.3}Ga_{0.7}Se_2$, and 2.107 eV, 2.075 eV, 2.019 eV in $p-TlIn_{0.5}Ga_{0.5}Se_2$ respectively, at sample temperatures of 10 K, 140 K …
Quark And Lepton Masses From Fundamental Algebra With Exact Color Symmetry, Engi̇n Arik, Meti̇n Arik, Ufuk Kayserilioglu, M. Burcin Unlu
Quark And Lepton Masses From Fundamental Algebra With Exact Color Symmetry, Engi̇n Arik, Meti̇n Arik, Ufuk Kayserilioglu, M. Burcin Unlu
Turkish Journal of Physics
We propose a deformed algebra of creation and annihilation operators relating quark-lepton states. A diagonal mass operator with three parameters together with the three deformation parameters of the algebra gives a reasonable fit to observed quark-lepton masses.
On Integrable Systems Related To Semisimple Lie Groups, G. A. Keri̇mov
On Integrable Systems Related To Semisimple Lie Groups, G. A. Keri̇mov
Turkish Journal of Physics
Quantum scattering systems related to the noncompact semisimple Lie groups G in the sense that the Hamiltonian of the system can be written as a function of the Casimir operator of G are considered. The S-matrix for such systems are defined in terms of an interwining operator of underling symmetry group G.
Barrier Heights Of Antimony / And Bismuth / P -Silcon (100) Junctions, A. A. Oberafo, A. Z. Ziriki
Barrier Heights Of Antimony / And Bismuth / P -Silcon (100) Junctions, A. A. Oberafo, A. Z. Ziriki
Turkish Journal of Physics
Junctions were fabricated in vacuum of about $10^{-5}$ Torr by thermal evaporation of Sb or Bi onto chemically etched $p$-type silicon (100) substrates. The electrical properties were studied by current voltage (I-V) measurements. Some of the Sb and Bi junctions were heated-treated for $\frac{1}{2}$ hr at 200 and 150^oC, respectively. The barrier height (BH) was equal to 0.64 eV for both as-deposited and heat-treated Sb junctions, while it was 0.56 and 0.74 eV for as-deposited and heat-treated Bi Junctions, respectively. These observatimons indicate that for Sb junctions, annealing at a temperature of 200^oC resulted only in partial elimination of any …
Mass-Radius Relations For Helium White Dwarfs, Ri̇kkat Ci̇velek, Ni̇lgün Kiziloğlu
Mass-Radius Relations For Helium White Dwarfs, Ri̇kkat Ci̇velek, Ni̇lgün Kiziloğlu
Turkish Journal of Physics
We studied the static mass-radius relation of white dwarf stars with masses greater than 0.45 $M_\odot$. We assumed pure degenerate helium interiors at a finite temperature with luminosity-mass ratio due to neutrino energy loss. We compared the obtained M-R relation with those of other writers.
The Growth Of P-Type A^{Iii} B^{Iii} C_2^{V I} Single Crystals, Beki̇r Gürbulak, Cevdet Coşkun, Seydi̇ Doğan, Aytunç Ateş, Yahya Kemal Yoğurtçu
The Growth Of P-Type A^{Iii} B^{Iii} C_2^{V I} Single Crystals, Beki̇r Gürbulak, Cevdet Coşkun, Seydi̇ Doğan, Aytunç Ateş, Yahya Kemal Yoğurtçu
Turkish Journal of Physics
$A^{III}B^{III}C_2^{VI}$ single crystals were grown by the modified Bridgman-Stockbarger method, a procedure similar to direct freezing in our crystal growth laboratory. $A^{III}B^{III}C_2^{VI}$ compounds are collected into two groups (III. group: TI, Ga, In and VI. group: Se, S, Te): 1. TlGaSe$_2$, TlGaS$_2$ and TlInS$_2$ have layer structure. 2. TlInSe$_2$, TlInTe$_2$ and TlGaTe$_2$ have chained structure. The main reasons such crystals grown with this method is similar to the direct freezing method because 1) quality of crystals is the same as crystals grown by other methods, and 2) growth time of crystals is shorter by about 5-10 days. None of the …
Doping Of High-Temperature Superconductors, Sh. Meretliev, K. B. Sadykov, A. Berkeliev
Doping Of High-Temperature Superconductors, Sh. Meretliev, K. B. Sadykov, A. Berkeliev
Turkish Journal of Physics
High-temperature superconducting ceramics systems YBaCuO and BiSrCaCuO, both doped by Pb, Sb, Li, K, Na and non-doped, have been produced by the method of solid phase reaction synthesis. The principle of controlled valency by Vervey has been used to characterize high-temperature superconductors. High-temperature superconducting ceramics have been obtained with properties stable in time by single-purpose doping.
Chemically Synthesised Cd_{(1-X)}Zn_Xse Thin Films: Spectro-Structural And Microscopic Studies, D. S. Sutrave, G. S. Shahane, V. B. Patil, L. P. Deshmukh
Chemically Synthesised Cd_{(1-X)}Zn_Xse Thin Films: Spectro-Structural And Microscopic Studies, D. S. Sutrave, G. S. Shahane, V. B. Patil, L. P. Deshmukh
Turkish Journal of Physics
This paper presents information pertaining to the chemo-mechanical synthesis of (Cd,Zn) Se thin films with a variable composition which has been brought about with the objective to study deposition history and growth kinetics, as well as structural changes and the optical properties. The effect of various process parameters, such as deposition time and temperature, concentration of species, speed of the substrate rotation, pH etc., on the growth and quality of the films is studied experimentally. At first sight, mechanistic interpretation of the reaction mechanism is given based on the influence of the process parameters on the film growth and the …
Thickness Dependence Of C/A Polytwin Structures Observed In Epitaxial Oxide Ferroelectric Thin Films, S. Pami̇r Alpay, Alexander L. Roytburd
Thickness Dependence Of C/A Polytwin Structures Observed In Epitaxial Oxide Ferroelectric Thin Films, S. Pami̇r Alpay, Alexander L. Roytburd
Turkish Journal of Physics
Ferroelectric or ferroelastic epitaxial films undergoing a cubic-to-tetragonal phase transformation usually relax the resultant strain energy due to lattice misfit by forming a polytwin (polydomain) structure. Polydomain formation occurs at the expense of building interdomain interfaces and microstresses which develop at the film-substrate interface due to the periodic deviation of the strain. The interplay between these components results in a critical thickness for domain formation below which the polydomain structure is not stable. In this article, we investigate the film thickness dependence of a polydomain structure using a thermodynamical approach.
The Interaction Of The Dipole Moment Of The Water Molecule With The Interface States Of The Cuprous Oxide/Cupric Oxide Junction, Necmi̇ Seri̇n, Tülay Seri̇n, Basri̇ Ünal
The Interaction Of The Dipole Moment Of The Water Molecule With The Interface States Of The Cuprous Oxide/Cupric Oxide Junction, Necmi̇ Seri̇n, Tülay Seri̇n, Basri̇ Ünal
Turkish Journal of Physics
An Au/CuO/Cu$_{2}$O/Cu sandwich structure has been obtained by growing successive Cu$_{2}$O and CuO layers on a Cu sheet. A gold metal contact was formed CuO side at pressure of $1\times10^{-6}$ Torr. Current-voltage characteristics and capacitance of the system were seen to change over a great extent due to the presence of humidity. The effect of the humidity on Au/CuO/Cu$_{2}$O/Cu is explored through the effect of water's dipole moment.
Two-Photon Absorption In Size-Quantized Semiconductors With Degenerated Valence Band, T. G. Ismailov, M. A. Bagirov, B. Ünal
Two-Photon Absorption In Size-Quantized Semiconductors With Degenerated Valence Band, T. G. Ismailov, M. A. Bagirov, B. Ünal
Turkish Journal of Physics
Two photon absorption in size-quantized films of semiconductors with degenerated band structures are investigated. The carrier energy spectrum and wavefunctions in the bands are calculated using two-band Kane model with spin taken into accont. Two-photon absorption coefficients for different polarizations of incident radiations are calculated. The strong dependence of two-photon absorption on polarizations are stated.
Welcoming Address: "Mathematical Concepts In Politics", Erdal İnönü
Welcoming Address: "Mathematical Concepts In Politics", Erdal İnönü
Turkish Journal of Physics
No abstract provided.
Analysis On The 2-Dim Quantum Poincare Group At Roots Of Unity, Haji Ahmedov
Analysis On The 2-Dim Quantum Poincare Group At Roots Of Unity, Haji Ahmedov
Turkish Journal of Physics
2--Dim quantum Poincar\'e Group $E_q(1,1)$ at roots of unity, its dual $U_q(e(1,1))$ and some of its homogeneous spaces are introduced. Invariant integrals on $E_q(1,1)$ and its invariant discrete subgroup $E(1,1\mid p)$ are constructed. $*$--Representations of the quantum algebra $U_q(e(1,1))$ constructed in the homogeneous space $SO(1,1\mid p)$ are integrated to the pseudo--unitary representations of $E_q(1,1)$ by means of the universal $T$--matrix. $U_q(e(1,1))$ is realized on the quantum plane $E_q^{(1,1)}$ and the eigenfunctions of the complete set of observables are obtained in the angular momentum and momentum basis. The matrix elements of the pseudo--unitary irreducible representations are given in terms of the …
Noncommutativity In String Theory And Large Extra Dimensions, Farhad Ardalan
Noncommutativity In String Theory And Large Extra Dimensions, Farhad Ardalan
Turkish Journal of Physics
Noncommutativity of space coordinates of string theory are reviewed and are related to the large extra dimension solution of the hierarchy problem.
On Fermi - Bose Symmetry In Conformal Field Theory, A. Belavin
On Fermi - Bose Symmetry In Conformal Field Theory, A. Belavin
Turkish Journal of Physics
The minimal models of CFT possess a few algebraic structures. Besides the Virasoro Algebra which is an explicit symmetry of these models they have also Quantum Group structure and Fermi-Bose duality. We discuss the relationship between these things.
Monopole Equations On R^8: The Energy Integral, Ayşe Hümeyra Bi̇lge, Teki̇n Dereli̇, Şahi̇n Koçak
Monopole Equations On R^8: The Energy Integral, Ayşe Hümeyra Bi̇lge, Teki̇n Dereli̇, Şahi̇n Koçak
Turkish Journal of Physics
We discuss the Seiberg-Witten theory in four dimensions and possible generalizations to eight dimensions. We propose an action which is minimized by a set of monopole equations, previously obtained as a generalization of Seiberg-Witten theory to eight manifolds with Spin(7) holonomy.
Kerr Spinning Particle, A. Burinskii
Kerr Spinning Particle, A. Burinskii
Turkish Journal of Physics
We give a brief review of the problems connected with the model of spinning particle based on the Kerr geometry. We consider peculiarities of the Kerr rotating black hole solution in gravity, supergravity and low energy string theory. A non-trivial supergeneralization of the Kerr-Newman solution to broken N=2 supergravity is considered. \par The problem of source of the Kerr geometry is discussed, and we consider some arguments in favor of the supersymmetric Fermi-ball model for the Kerr source based on the Witten $U(1)\times U(\tilde 1)$ field model for superconducting strings.