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Articles 10321 - 10350 of 10730
Full-Text Articles in Physical Sciences and Mathematics
The Relation Between Dislocation Density And Crystal Crosscut In \Beta-Sn Grown By Modified Bridgman Method, Bahattin Düzgün, İbrahim Karaman, Nazım Uçar
The Relation Between Dislocation Density And Crystal Crosscut In \Beta-Sn Grown By Modified Bridgman Method, Bahattin Düzgün, İbrahim Karaman, Nazım Uçar
Turkish Journal of Physics
Crystals $\beta$-Sn are grown from ingots of 99.99\% purity by modified Bridgman method under $10^{-3}$ torr pressure and oriented by Laue back reflection method. The relation between crystal crosscut and dislocation density calculated using etch hillock technique is investigated. It is found that the dislocation density increases with increasing crystal crosscut.
A Study Of Events From Si 28 With Emulsion At 4.5 A Gev/C Without Target Fragmentation, A.A. El-Daiem
A Study Of Events From Si 28 With Emulsion At 4.5 A Gev/C Without Target Fragmentation, A.A. El-Daiem
Turkish Journal of Physics
Atotal sample of 1000 inelastic interactions of Si$^{28}$ in emulsion at 4.5 A GeV/c has been used characteristics of projectile fragments. This paper is therefore to devoted to the study of projectile fragments, with special attention to the class of events $n_h$=0, in which the traget nucleus is unwounded. This paper include the multiplicity distributinon and angular distributions of projectile fragments.
Isotope Effect And Phonon Softening In Superconducting Borocarbides And Boronitrides, Tuğrul Haki̇oğlu, Valery A. Ivanov
Isotope Effect And Phonon Softening In Superconducting Borocarbides And Boronitrides, Tuğrul Haki̇oğlu, Valery A. Ivanov
Turkish Journal of Physics
The isotope effect in the recently disvovered class o superconductors LuNi_2B_2C and La_3Ni_2B_2N_3 is investigated in the context of electron-squezed phonon interaction renormalizing the Ni-d electron-electron correlations. Squeezed phonon mode originates from the anharmonic character of the tetragonal Ni-B structure and is polarized in the vortical direction to the Ni layers. The isotope effect arises as a result of the zero point motion of the Ni-Ni d-electron hopping amplitude dominantly due to this vertical phonon mode. Within this model the isotope exponent is calculated to be \alpha_B \leq 0.20 as compared to the recently found experimental value \alpha_B^{exp} = 0.27 …
Structural And Optical Characterisation Of Vacuum Deposited Cdte Thin Films, Murat Bayhan
Structural And Optical Characterisation Of Vacuum Deposited Cdte Thin Films, Murat Bayhan
Turkish Journal of Physics
The structural and optical properties of vacuum deposited CdTe thin films on glass substrates were investigated. The effect of the heat treatment in air over the former properties of the layers was also examined. Grain sizes of air heated layers estimated by net broading in the XRD spectra were found to be larger than as-grown layers, confirming that grain growth had occurred during the heat treatment. RHEED patterns of the layers grown at substrate temperatures between 150°C and 170°C had a distinct \{111\} preferred orientation. As-grown CdTe layers were slightly p-type, but highly resistive. Air heat treated layers were p-type …
The Space-Time Critical Dimension Of An Open Parabosonic String, N. Mebarki & N. Belaloui, M. Haouchine
The Space-Time Critical Dimension Of An Open Parabosonic String, N. Mebarki & N. Belaloui, M. Haouchine
Turkish Journal of Physics
Using analytical properties of a 1-loop open parabosonic M-point transition amplitude, we show that the space-time critical dimension depends on the order of the paraquantization.
Study Of Emission Parameters Of Ir(Iii)-Ba Film System, F. K. Yusifov, A. K. Orujov
Study Of Emission Parameters Of Ir(Iii)-Ba Film System, F. K. Yusifov, A. K. Orujov
Turkish Journal of Physics
Electrophysical properties of Ir(III)-Ba metal-film system have been studied by thermoionic emission (TE), surface ionization (SI) and thermal desorption spectroscopy (TDS) methods. It has been found that the optimum coverage of barium atoms on iridium (III) face is \theta_{opt} = 0.70 \pm 0.05. The dependence of fractional charge of Richardson constant of Ir(III)-Ba metal-film system on coverage \theta of the Ba atoms in the interval 0 \leq \theta \leq 1 has been experimentally obtained. The dependence of work function of Ir(III)-Ba metal-film system on coverage \theta of Ba atoms has been obtained.
Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş
Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş
Turkish Journal of Physics
In this work, the bulk modulus values for liquid alkali metal alloys near melting point are studied in the framework of the Gibbs-Bogoliubov method. We use the local Heine-Abarenkov pseudopotential and Ichimaru-Utsumi screening function in these alloys. The results are compared with experimental and theoretical results.
Anisotropic Motion Of Lipids In Hydrophobic Core Of Dppc Bilayers. Simulation Of Esr Spectra, Canan Teti̇k, Mustafa Korkmaz
Anisotropic Motion Of Lipids In Hydrophobic Core Of Dppc Bilayers. Simulation Of Esr Spectra, Canan Teti̇k, Mustafa Korkmaz
Turkish Journal of Physics
Planar samples prepared by drying phospholipid dispersions on glass slides provide a convenient model to examine motion and orientation in lipid bilayer structures. In the present work, hydrophobic cores of DPPC multibilayers were studied using a 16-DSA spin label consisting of a nitroxide free radical bonded to the 16 position of stearic acid. This spin label is in great demand for investigation of phase transitions occurring in the hydrophobic cores of lipid multibilayers. Thus, its room temperature motional and orientational features in phospholipid bilayers must be known accurately to avoid any misinterpretation in using it in these types of studies. …
Statistics And Size-Quantized Anisotropy Of Electron States In N-Ge And N-Si Films, Bahshali Kuliev, Vugar Gadjiev
Statistics And Size-Quantized Anisotropy Of Electron States In N-Ge And N-Si Films, Bahshali Kuliev, Vugar Gadjiev
Turkish Journal of Physics
The wave functions and energy spectrum of electrons in size-quantized n-Ge and n-Si films are obtained and the anisotropy of the electron state density is investigated. Also, the analytical expressions for the electronic part of heat capacity at the various approximations of electron gas degeneration are obtained.
Doping Effects Of Ga And Te On The Kinetic Coefficients Of Rhombohedral And Cubic Phases Of Ge_{1-X} Ga_X Te Solid Solution Alloys, T. Atalay, M.H. Akperov
Doping Effects Of Ga And Te On The Kinetic Coefficients Of Rhombohedral And Cubic Phases Of Ge_{1-X} Ga_X Te Solid Solution Alloys, T. Atalay, M.H. Akperov
Turkish Journal of Physics
In this study Ga and Te doping effects on the kinetic parameters (thermo e.m.f., electrical conductivity, heat conductivity, Hall and Nernst-Ettingshausen coefficients) of the rhombohedral and cubic phases of Ge_{1-x} Ga_x Te (0 < x \leq 0,06) solid solutions has been investigated between 77-900 K temperature intervals. Increase in the amount of Te increases hole concentration and reduces lattice constant, whereas rhombohedral propeties of GeTe rises with increase of Ga concentration. The observed anomalies on the kinetic parameters may be explained qualitatively by the complexity of the Fermi surface shape and the zone model of GeTe which involves the seperation of the L extremums that is same for ``\alpha'', ``\beta'' and ``\gamma'' phases of the compound.
An Interoperability Infrastructure For Developing Multidatabase Systems, Asuman Doğac, Gökhan Özhan, Ebru Kılıç, Fatma Özcan, Sena Nural, Sema Mancuhan, Cevdet Dengi, Pınar Köksal, Uğur Halıcı, Budak Arpınar, Cem Evrendilek, Vahid Sadjadi
An Interoperability Infrastructure For Developing Multidatabase Systems, Asuman Doğac, Gökhan Özhan, Ebru Kılıç, Fatma Özcan, Sena Nural, Sema Mancuhan, Cevdet Dengi, Pınar Köksal, Uğur Halıcı, Budak Arpınar, Cem Evrendilek, Vahid Sadjadi
Turkish Journal of Electrical Engineering and Computer Sciences
A multidatabase system (MDBS) allows the users to simultaneously access autonomous, heterogeneous databases using a single data model and a query language. This provides for achieving interoperability among heterogeneous, federated DBMSs. In this paper, we describe the interoperability infrastructure of a multidatabase system, namely METU Interoperable DBMS (MIND). The architecture of MIND is based on OMG distributed object management model. It is implemented on top of a CORBA compliant ORB, namely, ObjectBroker. The interface of the generic database object is defined in CORBA IDL and multiple implementations of this interface, one for each component DBMSs, namely, Oracle 7, Sybase, Adabas …
Performance Of Prefiltered Model-Based Frequency Estimators, Mustafa A. Altınkaya, Bülent Sankur, Emin Anarım
Performance Of Prefiltered Model-Based Frequency Estimators, Mustafa A. Altınkaya, Bülent Sankur, Emin Anarım
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, the performance improvement due to prefiltering of inputs in model-based frequency estimators is investigated based on simulation experiments. Initial estimates on the tone frequency locations, which are obtained via DFT peak picking type preanalysis, are used to design a prefilter to remove noise and interference. The simulations indicate that prefiltering can improve the accuracy of Pisarenko and AR frequency estimators and MUSIC and KT frequency estimators with low subspace order significantly. The SNR thresholds of model-based frequency estimators are lowered by prefiltering. Additionally, interesting trade-offs between prefiltering gain and the gain due to subspace noise filtering have …
Analysis Of Images Of Cells With Neurites, Florence Cloppet, Georges Stamon
Analysis Of Images Of Cells With Neurites, Florence Cloppet, Georges Stamon
Turkish Journal of Electrical Engineering and Computer Sciences
This study is concerned with the segmentation of cytological images and extraction of cellular entities in order to provide quantitative data about the number of cells in culture (statistical tests, morphology, model of evolution, etc). This quantitative supply is useful in biology to evaluate the consequences of the application of active substances on morphological changes and cellular viability. It is related to the conception of a system dedicated to automatic analysis of cell images, in order to evaluate the effects of drugs on the morphology of neuronal cells. We use a cooperative region / contour segmentation, which gives closed polygonal …
Imaging Electrical Current Density Using Nuclear Magnetic Resonance, B. Murat Eyüpoğlu, Ravinder Reddy, John S. Leigh
Imaging Electrical Current Density Using Nuclear Magnetic Resonance, B. Murat Eyüpoğlu, Ravinder Reddy, John S. Leigh
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, images of nonuniform and uniform electric current density in conductor phantoms, which contain magnetic resonance active nuclei, are produced using Magnetic Resonance Imaging (MRI). A standard spin echo pulse sequence is used, with the addition of a bipolar current pulse. The flux density parallel to the main magnetic field, generated by the current pulse, is encoded in the phase of the complex MR image. The spatial distribution of magnetic flux density is extracted from the phase image. Current density is calculated using the magnetic flux density. This fairly recent technique is known as Magnetic Resonance Current Density …
Use Of The Magnetic Field Generated By The Internal Distribution Of Injected Currents For Electrical Impedance Tomography (Mr-Eit), Y. Zi̇ya İder, Özlem Bi̇rgül
Use Of The Magnetic Field Generated By The Internal Distribution Of Injected Currents For Electrical Impedance Tomography (Mr-Eit), Y. Zi̇ya İder, Özlem Bi̇rgül
Turkish Journal of Electrical Engineering and Computer Sciences
In two dimensional conventional Electrical Impedance Tomography (EIT), volume conductor is probed by means of injected currents, and peripheral voltage measurements are used as input to the reconstruction algorithm. The current that flows in the 2D object creates magnetic fields that are perpendicular to the plane of imaging. Such magnetic fields can be measured using magnetic resonance tomography. In this study, use of this magnetic field generated by the injected currents, for the purpose of reconstructing the conductivity distribution, is studied. Sensitivity matrix relating the magnetic field to the element conductivities is calculated using the Finite Element Method and Biot-Savart …
Fdtd Evaluation Of The Sar Distribution In A Human Head Near A Mobile Cellular Phone, Selçuk Paker, Levent Sevgi̇
Fdtd Evaluation Of The Sar Distribution In A Human Head Near A Mobile Cellular Phone, Selçuk Paker, Levent Sevgi̇
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, Finite-Difference Time-Domain (FDTD) method is used to calculate the Specific Absorbtion Rate (SAR; defined as the power absorbed by unit mass of the tissue) distribution in a human head near a hand-held cellular phone. A three dimensional FDTD algorithm is built in cartesian coordinates. A discrete human head model, derived from a Nuclear Magnetic Resonance (NMR) image by semi-automatic algorithm, is located within FDTD volume together with a discrete hand-held receiver model. FDTD simulations are carried out for both european GSM (operating at 900MHz) and DECT (operating at 1.8GHz) systems with a quarter-wavelength antenna, mounted on top …
Cardiac Passive Acoustic Localization: Cardiopal, Yildirim Bahadirlar, Hali̇l Özcan Gülçür
Cardiac Passive Acoustic Localization: Cardiopal, Yildirim Bahadirlar, Hali̇l Özcan Gülçür
Turkish Journal of Electrical Engineering and Computer Sciences
A novel non-invasive system is proposed as an adjunct diagnostic tool for cardiac disorders, which is based on processing of the heart sounds acquired using a specially designed 2-D passive acoustic array. In addition to the acoustic array, the system consists of a personal computer, specially developed instrumentation and interface hardware and an adaptive array processing scheme. A signal model is constructed in accordance with the basic assumptions made for very near-field low frequency sources. The multiple signal characterization (MUSIC) method together with the model is used for the localization of assumed point sources in the heart. Locations of the …
On Certain Varieties Of Semigroups, A. Tiefenbach
On Certain Varieties Of Semigroups, A. Tiefenbach
Turkish Journal of Mathematics
In this paper we generalize the class of completely regular semigroups (unions of groups) to the class of local monoids, that is the class of all semigroups where the local subsemigroups \( aSa \) are local submonoids. The sublattice of this variety \( (\mathbf{L}(\caL(\cam)) \) covers another lattice isomorphic to the lattice of all bands \( ([x^2 = x]). \) Every bundvariety \( \cau \) has as image the variety \( \Phi - \cau, \) which is the class of all semigroups, where \( \Phi \) is a \( \cau \)-congruence \( (a \Phi b \Leftrightarrow aSa = bSb). \) …
Theorems On Three-Term Relations For Hardy Sum, Y. Şi̇mşek
Theorems On Three-Term Relations For Hardy Sum, Y. Şi̇mşek
Turkish Journal of Mathematics
Some three-term and mixed three-term relations for Hardy sums were given by Goldberg [7]. His proofs are based on Bernd's transformation formulae for the logarithms of the classical Theat-functions. Pettet and Sitaramachandararo [9] proved elementary proofs for all of Goldberg's results and also proved some three-term relations of Dedekind sums. In this paper, some new theorems on three-term relations for hardy sums were found by applying derivative operator to three-term polynomial relation. Furthermore, proofs of the reciprocity relations for Hardy sums are presented in a more concise way from the original proofs of Berndt [2, 3, 4] and Goldberg [7].
On The Action Of Steenrod Operations On Polynomial Algebras, İ. Karaca
On The Action Of Steenrod Operations On Polynomial Algebras, İ. Karaca
Turkish Journal of Mathematics
Let \( \bba \) be the mod-\( p \) Steenrod Algebra. Let \( p \) be an odd prime number and \( Z_{p} = Z/pZ \). Let \( P_{s} = Z_{p} [x_{1},x_{2},\ldots,x_{s}]. \) A polynomial \( N \in P_{s} \) is said to be hit if it is in the image of the action \( A \otimes P_{s} \ra P_{s}. \) In [10] for \( p=2, \) Wood showed that if \( \a(d+s) > s \) then every polynomial of degree \( d \) in \( P_{s} \) is hit where \( \a(d+s) \) denotes the number of ones in the …
Dold-Kan Type Theorems For N-Types Of Simplicitial Commutative Algebras, Z. Arvasi̇, M. Koçak
Dold-Kan Type Theorems For N-Types Of Simplicitial Commutative Algebras, Z. Arvasi̇, M. Koçak
Turkish Journal of Mathematics
A functor from simplicial algebras to crossed \( n \)-cubes is shown to be an embedding on a reflexive subcategory of the category of simplicial algebras that contains representatives for all \( n \) types.
From Simplicial Groups To Crossed Complexes, Z. Arvasi̇
From Simplicial Groups To Crossed Complexes, Z. Arvasi̇
Turkish Journal of Mathematics
In this paper, we will give a short proof of the construction of the crossed complex of groups by using the higher order Peiffer elements.
On The Validity Of The Borel-Hirzebruch Formula For Topological Actions, D. Dönmez
On The Validity Of The Borel-Hirzebruch Formula For Topological Actions, D. Dönmez
Turkish Journal of Mathematics
We defined an equivalence among group actions and find sufficient conditions for actions of compact connected Lie groups on Euclidean spaces for which the topological version of the Borel-Hirzebruch formula holds.
On The Parabolic Class Number Of Some Subgroups Of Hecke Groups, R. Keski̇n
On The Parabolic Class Number Of Some Subgroups Of Hecke Groups, R. Keski̇n
Turkish Journal of Mathematics
In this paper we calculate the parabolic class number of subgroups of Hecke groups ( H(\sqrt{2}), H (\sqrt{3}) ).
Locally Volume-Minimizing Codimension-One Foliation Of The Solid Torus, İ. Kocayusufoğlu, D. L. Jhonson
Locally Volume-Minimizing Codimension-One Foliation Of The Solid Torus, İ. Kocayusufoğlu, D. L. Jhonson
Turkish Journal of Mathematics
The aim of this paper is to construct a specific codimension-1 foliation of \( D^2 \times S^1 \) with one Reeb component, and to show that this foliation locally minimizes the volume among foliations with the boundary torus as a leaf.
Codes On Superelliptic Curves, F. Özbudak, M. Glukhov
Codes On Superelliptic Curves, F. Özbudak, M. Glukhov
Turkish Journal of Mathematics
The purpose of this paper is to apply superelliptic curves with a lot of rational points to construct rather good geometric Goppa codes.
Elastic Scattering Of 344.5 Mev ^{12}C Ions From ^{11}B Nucleus, S.A.E. Khallaf, M.A. Abdel-Rahman, S.K. Abdel-Rahman, S.W.Z. Mahmoud
Elastic Scattering Of 344.5 Mev ^{12}C Ions From ^{11}B Nucleus, S.A.E. Khallaf, M.A. Abdel-Rahman, S.K. Abdel-Rahman, S.W.Z. Mahmoud
Turkish Journal of Physics
The angular distribution of the elastic scattering differential cross section of 344.5 MeV $^{12}$C ions from $^{11}$B nucleus is calculated and compared with the experimental data as well as the previously published calculations. The real part of the central optical potential is derived using the double-folding and single-folding procedures assuming Gaussian forms of the nucleon-nucleon and alpha-nucleon interactions, respectively. A nuclear matter density distribution function of $^{11}$B consisting of a spherical part plus a quadrupole term is used. The inclusion of the quadrupole term is found necessary to obtain good fits to the experimental data.
The Influence Of The Dispersion Of Boron Silicate On The Migration Of Non-Equilibrium Charge Carriers Generated By Eect Of An Electric Discharge, A.M. Hasanov
Turkish Journal of Physics
ESR was used in an investigation of the influence of Boron Silicate dispersion on the accumulation of paramagnetic centers (PC). It was observed that the rate of accumulation of PC increase by increasing of the grain size (r). At $r < 0.08$ mm the electrons ($F^+$-centers) are localized on the surface and with increasing grain size up to $0.08 < r < 0.22$ mm charge stratification takes place, the electrons are distributed in near-surface layer and the holes ($V$-centers) are localized in the bulk of the insulator. It was established that the transport of non-equilibrium charge carriers (NCC) from the bulk to the surface of Boron Silicate was due to a drift from the depth $(d \sim 10 \mu m)$ to a bulk-charge field generated by an electric discharge. The value of the surface field $E_s \sim 10^5 V/cm$ is determined by experimental results of the data. The kinetics of the isothermal annealing (300 K) are used to establish the influence of the surface field on the annihilation of NCC in the ''dead'' layer of separated charges.
Dynamical System Topology Preserved In The Presence Of Noise, Judy A. Kennedy, James A. Yorke
Dynamical System Topology Preserved In The Presence Of Noise, Judy A. Kennedy, James A. Yorke
Turkish Journal of Mathematics
We first give a precise definition of the terms ``topological horseshoe'' and ``generalized quadrilateral'' and then examine the behavior of a homeomorphism F on a locally compact, separable, locally connected metric space X (X is usually a manifold in applications) such that F restricted to some generalized quadrilateral Q in X is a topological horseshoe map. For a set Q \subset X we define and describe (1) the permanent set Z of Q to be \{x\in X:F^n(x)\in Q for all integers n\}, and (2) the entrainment set of Q to be E(Q)=\{x\in X: F^{-n} (x)\in Q for all sufficiently large …
On The Cohomology Ring Of The Infinite Flag Manifold Lg/D, Cenap Özel
On The Cohomology Ring Of The Infinite Flag Manifold Lg/D, Cenap Özel
Turkish Journal of Mathematics
In this work, we discuss the calculation of cohomology rings of LG / T. First we describe the root system and Weyl group of LG, then we give some homotopy equivalences on the loop groups and homogeneous spaces, and investigate the cohomology ring structures of LSU_2 /T and \Omega SU_2. Also we prove that BGG-type operators correspond to partial derivation operators on the divided power algebras.