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Articles 9931 - 9960 of 10317
Full-Text Articles in Physical Sciences and Mathematics
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.
Fuzzy Ideals In Gamma Near-Rings, Young Bae Jun, Mehmet Sapanci, Mehmet Ali̇ Öztürk
Fuzzy Ideals In Gamma Near-Rings, Young Bae Jun, Mehmet Sapanci, Mehmet Ali̇ Öztürk
Turkish Journal of Mathematics
The aim of this paper is to introduce the notion of fuzzy left (resp. right) ideals of \Gamma-near-rings, and to study the related properties.
Symmetry Of C_{60} And A Force Constant Model For Vibrational Modes, Ramazan Koç, Hayriye Tütüncüler
Symmetry Of C_{60} And A Force Constant Model For Vibrational Modes, Ramazan Koç, Hayriye Tütüncüler
Turkish Journal of Physics
A force-constant model for the vibrational modes in $C_{60}$ is presented. The Keating type potential is adopted for calculating the dynamical matrix. Using symmetries of the molecule, the dynamical matrix which yields the vibrational modes is block-diagonalized. We summarize the role of group theory in specifying the vibrational modes. The results are in excellent agreement with experiments. The effect of bond-stretching force constants on the vibrational modes will be presented.
Q1d-Polarons In Rigid Boundary Cylindrical Wires: "Mixed-Coupling Approximation", R. T. Senger And A. Erçelebi̇
Q1d-Polarons In Rigid Boundary Cylindrical Wires: "Mixed-Coupling Approximation", R. T. Senger And A. Erçelebi̇
Turkish Journal of Physics
We consider the interaction of a confined electron with bulk polar-optical phonons in a cylindrical quantum well wire with infinite boundary potential. Expressions for the polaron self energy and mass are derived within a composite variational scheme consisting of a strong-coupling characterization imposed in the lateral directions and a weak-coupling LLP-counterpart structured along the length of the wire. The formulation is seen to be rather commendable and yields a sensible description of the Q1D-polaron in thin wires of weak or intermediate electron-phonon coupling strengths.
Singlet Axial Current Form Factor In The Chiral Solitonic Bag Model With Massive Quarks, N. Karagöz
Singlet Axial Current Form Factor In The Chiral Solitonic Bag Model With Massive Quarks, N. Karagöz
Turkish Journal of Physics
Singlet axial current form factor $g_A^0$ is calculated as a function of bag radius in the two flavor chiral solitonic bag model with unequal quark masses. The value of $g_A^0$ near 1 fm is sufficiently small.
Current-Voltage Characteristics And Photoresponse Of Metal Metal Devices, K. Singh, S.N.A. Hammond
Current-Voltage Characteristics And Photoresponse Of Metal Metal Devices, K. Singh, S.N.A. Hammond
Turkish Journal of Physics
Thin films (35 \AA) of $Al_2O_3$ on glass slides have been used for the fabrication of $Al/Al_2O_3/Al, Ag/Al_2O_3/Al$ and $Cu/Al_2O_3/Al$ devices. The room temperature current-voltage characteristics and the dependence of current densities of these devices at various wavelength $(\lambda)$ of light were measured. The results obtained on current density and photocurrent show that $Al_2O_3$ films have the potential for wider applications like antireflective coatings or treatments in photovoltaic devices, transparent insulation materials, and optical trapping surfaces in many electronic devices.
Study Of Kinetic Coefficients Of (Gete)_{1-X} - (Ga_2te_3)_X Solid Solutions, M.H. Akperov, T. Atalay, H. Aşkin, A.M. Erer
Study Of Kinetic Coefficients Of (Gete)_{1-X} - (Ga_2te_3)_X Solid Solutions, M.H. Akperov, T. Atalay, H. Aşkin, A.M. Erer
Turkish Journal of Physics
In this study, such kinetic cparametres as thermoelectro motor force (thermo e.m.f), electrical coductivity, heat conductivity, Hall and Nernst-Ettingshausen coeficients are investigated, as a function of chemical composition of $(GeTe)_{1-x}-(Ga_2Te_3)_x$ and temperature, by physicochemical methods and x-rays analysis. The kinetic parameters $(GeTe)_{1-x}-(Ga_2Te_3)_x$ solid solutions are investigated between x=0 and 0,015 and between 77 and 900 K. Adding of $Ga_2Te_3$ to GeTe reduces the phase transition temperature of $\beta$-GeTe to $\alpha$-GeTe. It is observed that in the region of solid solution the rhombohedral modification of GeTe are protected. Doping of GeTe with $Ga_2Te_3$ does not affect the kinetic parameters of GeTe. …
Influence Of Medium On Generation Of Localized Charges In Beo By The Exposure Of The Electrical Discharge In Air And Oxygen, M.M. Aliev
Turkish Journal of Physics
The EPR-method is used to investigate the regularity of the formation of paramagnetic $ F^+$- and $ V^-$ centers (PC) in BeO which are generated by barrier electrical discharge (ED) in air and oxygen under reduced pressure. It was determined that, at different powers of discharge or parameters E/P, the maximums of kinetic curves of PC- accumulation in oxygen in comparison with air plasma forming medium are changed with resspect to both their value and position, depending on the interaction of oxygen atoms and ions $O, O^+, O^-, O^+_2, O^-_2,\ldots)$ with BeO surface. These exposures resulted in decreasing rate of …
The Submilimeter-Wave Rotational Spectrum Of Isopropyl Alcohol, C. Qajar, S. Musaev
The Submilimeter-Wave Rotational Spectrum Of Isopropyl Alcohol, C. Qajar, S. Musaev
Turkish Journal of Physics
The submilimeter-wave spectrum of the {\em trans} isopropyl alcohol was studied in the frequency range from 240 to 480 GHz. More than 170 lines were assigned to ground state transition. The identification of the high $J$ transitions was checked by centrifugal distortion analysis. The frequencies of all transitions were least squares fitted to the Watson's Hamiltonian, including two $P^8$ terms. The ground-state rotational constants are (in MHz) A = 8489.0150, B = 8041.9182, C = 4765.2326, which yield an asymmetry parameter $\kappa = 0.75986663$.
Shallow Donors In A Quantum Well Wire; Electric Field And Geometrical Effects, M. Ulaş, H. Akbaş, M. Tomak
Shallow Donors In A Quantum Well Wire; Electric Field And Geometrical Effects, M. Ulaş, H. Akbaş, M. Tomak
Turkish Journal of Physics
Subband and shallow donor binding energies are calculated. The emphasis is given on the electric field effects for wires of different shapes. It is shown that the donor binding energy is sensitive to the interplay of the electric field and geometrical effects.
The Eect Of Exposure Time To Clean Room Air On Characteristic Parameters Of Au /Epilayer N-Si Schottky Diodes, M. Sağlam, Ç. Nuhoğlu, E. Ayyildiz, A. Türüt, H.A. Çeti̇nkara
The Eect Of Exposure Time To Clean Room Air On Characteristic Parameters Of Au /Epilayer N-Si Schottky Diodes, M. Sağlam, Ç. Nuhoğlu, E. Ayyildiz, A. Türüt, H.A. Çeti̇nkara
Turkish Journal of Physics
A study has been made on determination and comparison of current-voltage (I-V) and capacitance-voltage (C-V) characteristics parameters of $Au/n-Si$ Schottky barrier diodes (SBDs) with and without thin native oxide layer fabricated on $n$-type $Si$ grown by LPE (Liquid-phase Epitaxy) technique. The native oxide layer with different thicknesses on chemically cleaned on $Si$ surface were obtained by exposing the surfaces to clean room air before evaporating metal. The native oxide thicknesses of samples D2, D3, D4 and D5 are in the form $D2 < D3 < D4 \leq D5$, depending on the exposing time. It has been seen that the values of barrier height $\Phi_b$ of samples D2(0.64 eV), D3(0.66 eV), D4(0.69 eV) and D5(0.69 eV) with the interfacial layer increased with increasing the exposure time and tended to that of the initial sample D1 (nonoxidezed sample, 0.74 eV), and thus also their I-V and C-V curves. The reverse current of sample D1 showed slight nonsaturating behavior. This ''soft'' behavior has been ascribed to the spatial inhomogeneity in the barrier heights at the MS interface. In particular, reverse bias curves of samples D2, D3, D4 and D5 have shown excellent saturation which may be attributed to the passivation of the semiconductor surface states by the native oxide layer which reduces the penetration of the wave functions of electron in the metal into the semiconductor. Especially, the I-V characteristics and experimental parameters of our devices are in agreement with recently reported results revealed by the pulsed surface photovoltage technique for the electronic properties of the HF-treated Si surface during initial oxidation in air.
Nanosecond Duration Broadband Luminescence Of Quartz Glasses, Maruf A. Kasymdzhanov, Pulat K. Khabibullaev, Saidislam S. Kurbanov
Nanosecond Duration Broadband Luminescence Of Quartz Glasses, Maruf A. Kasymdzhanov, Pulat K. Khabibullaev, Saidislam S. Kurbanov
Turkish Journal of Physics
The results of investigations of luminescence, excited by radiations of $N_2$- and $Nd^{3+}$: YAG-lasers ($\lambda = 337 nm, \lambda = 532 nm$) in high purity quartz glasses are reported. The luminescence has broad spectrum (350-850 nm) and very short duration (1-20 ns).
Magnetic Domain Structures In As-Quenched And Annealed Fe_{78}B_{13}Si_9 Metallic Glass Ribbons, Yücel Bi̇rol
Magnetic Domain Structures In As-Quenched And Annealed Fe_{78}B_{13}Si_9 Metallic Glass Ribbons, Yücel Bi̇rol
Turkish Journal of Physics
Among various soft magnetic materials, ferromagnetic glasses are superior to their crystalline counterparts as they possess no magnetocrystalline anisotropy owing to a non-crystalline structure. However, ferromagnetic glasses carry residual stresses and thus anisotropies of magnetostrictive origin in the as-quenched state. These stresses have an adverse effect on the magnetic softness and should be relieved in order to improve magnetic performance, particularly in magnetostrictive alloys. In the present work, the domain structures of Fe$_{78}$B$_{13}$Si$_9$ metallic glass, a highly magnetostrictive alloy, are characterized in the as-quenched and annealed states. The annealing treatments were carried out over a wide temperature range extending from …
Economic Analysis And Comparison Of Two Solar Energy Systems With Domestic Water Heating Systems, R. Kayali
Economic Analysis And Comparison Of Two Solar Energy Systems With Domestic Water Heating Systems, R. Kayali
Turkish Journal of Physics
In this work, an economic analysis of different types of thermosiphons and geysers and flat plate collectors and solar ponds employeed in conventional solar energy systems used in houses is analized and the results obtained for these systems are compared with each other. These comparisons show that when the inflation rate is 50\% or less solar energy systems are more economical than the other conventional systems, except for conventional systems in which solid fuels are used. If the calculations are done assuming that the consumer credit interest rate varies between 55-70\%, it is seen that solar energy systems will only …
Domain Structures Of Epitaxial Perovskite Ferroelectric Films: Part I. Theory, S. Pamir Alpay, Alexander L. Roytburd
Domain Structures Of Epitaxial Perovskite Ferroelectric Films: Part I. Theory, S. Pamir Alpay, Alexander L. Roytburd
Turkish Journal of Physics
Possible equilibrium domain structures due to elastic interactions between the film and the substrate as a result of a cubic-tetragonal transformation observed in epitaxial perovskite ferroelectric films are analyzed. Domain structures are compared in terms of their elastic energies. The formation of both two- and three-domain states is taken into account. Maps which shows domain stability regions are developed in coordinates of misfit strain and tetragonality of the lattice of the ferroelectric phase.
Observation Of Events At Very High Q^2 In E^+P Collisions At Hera, A. Wagner
Observation Of Events At Very High Q^2 In E^+P Collisions At Hera, A. Wagner
Turkish Journal of Physics
Data collected at the $e^+p$ collider HERA at DESY by the experiments H1 and ZEUS have allowed to probe a previously inaccessible domain of very large $Q^2$ in deep-inelastic $ep$ scattering. For $Q^2 > 15000 GeV^2$ both experiments see more events than expected assuming the Standard Model of deep-inelastic scattering. In this report the observed events, the theoretical expectations and their comparison are discussed.
A Review Of E^+E^- Linear Colliders, D. Trines
A Review Of E^+E^- Linear Colliders, D. Trines
Turkish Journal of Physics
No abstract provided.
Testing Deca-Tev Unified Compositeness At The 4 Tev \Mu_+\Mu_-Colliders, Vasily V. Kabachenko, Yury F. Pirogov
Testing Deca-Tev Unified Compositeness At The 4 Tev \Mu_+\Mu_-Colliders, Vasily V. Kabachenko, Yury F. Pirogov
Turkish Journal of Physics
In the framework of the unified compositeness of leptons, quarks and Higgs bosons, the hidden local symmetry $\hat H_{loc}=SU(2)_L\times U(1)_Y$ with the heavy composite vector bosons, in addition to the SM gauge bosons, is briefly described. Supplementary hypothesis of the vector boson dominance (VBD) of the SM gauge interactions is considered. It is argued that this should produce the universal dominant residual interactions of the SM composite particles, i.e., all of the fermions and Higgs bosons. Restrictions on the universal residual fermion-fermion, fermion-boson and boson-boson interactions due to the VBD are investigated. Manifestations of the residual interactions at the 4~TeV …
A Proposal For A Measurement Of The Nucleon Form Factors At An Asymmetric E^+E^- Linac-Ring Collider, R. Baldini, C. Bini, P. Patteri
A Proposal For A Measurement Of The Nucleon Form Factors At An Asymmetric E^+E^- Linac-Ring Collider, R. Baldini, C. Bini, P. Patteri
Turkish Journal of Physics
The neutron electromagnetic form factors have been measured for the first time in the time-like region in the $Q^2$ range between 3.6 and 6 $GeV^2$ by the FENICE experiment. The results show some unexpected features. First the neutron magnetic form factor turns out to be larger than the proton one, the neutron electric form factor being negligible. Then there are indications of a narrow structure very near the $N\overline{N}$ threshold, in the e^+e^- multihadronic annihilation. A new, high statistics experiment is needed to clarify the indications. An asymmetric, unconventional, linac-storage ring collider is proposed, using one of the existing high …
Main Parameters Of Linac-Ring Type E-Nucleus And \Gamma-Nucleus Colliders, Ş. Turköz
Main Parameters Of Linac-Ring Type E-Nucleus And \Gamma-Nucleus Colliders, Ş. Turköz
Turkish Journal of Physics
The main parameters of linac-ring type e-nucleus and $\gamma $-nucleus colliders are considered. It is shown that the reasonable luminosities at the multi-TeV energies can be achieved.
Production Of Susy Particles In Polarized \Gammap Collisions, A. Kandemi̇r
Production Of Susy Particles In Polarized \Gammap Collisions, A. Kandemi̇r
Turkish Journal of Physics
We discuss the production of several SUSY particles in the high energy collisions of the real photons off the protons within the MSSM. The polarizations of the colliding beams are also considered. The discovery mass limits for the squark and gluinos are presented and we conclude that the capacity of the future TeV scale $\gamma p$ colliders is quite promising in the search for SUSY particles.
Resummation Of Ir Renormalons In A Single Meson Photoproduction, Shahin S. Agaev
Resummation Of Ir Renormalons In A Single Meson Photoproduction, Shahin S. Agaev
Turkish Journal of Physics
Single pseudoscalar and vector mesons hard semi-inclusive photoproduction $\gamma h\rightarrow MX $ via higher twist mechanism is calculated using the QCD running coupling constant method. It is proved that in the context of this method a higher twist contribution to the photoproduction cross section cannot be normalized in terms of the meson electromagnetic form factor. The structure of infrared renormalon singularities of the higher twist subprocess cross section and the resummed expression (the Borel sum) for it are found. Comparisons are made with earlier results, as well as with leading twist cross section. Phenomenological effects of studied contributions for $\pi, …
Photoconductivity Studies Of Crystalline Si:H P-I-N, Ruhi Kaplan, Bengü Kaplan
Photoconductivity Studies Of Crystalline Si:H P-I-N, Ruhi Kaplan, Bengü Kaplan
Turkish Journal of Physics
Optically modulated photoconductivity (PC) properties of hydrogenated crystalline silicon (c-Si:H) with p-i-n junctions were investigated by frequency-resolved spectroscopy in the temperature range 20-290 K. The PC lifetime measurements of c-Si:H p-i-n show a second lifetime distribution which only dominates at low temperature under low illumination levels of excitation. Unlike the room temperature single lifetime distribution seen in c-Si:H p-i-n, the maximum of this second lifetime distribution shifts to longer times when the excitation intensity decreases, which reconciles with non-geminate pair recombination and thus the distant-pair model. In addition to lifetime measurements, the direct current-voltage (I-V) characteristics, the excitation light intensity- …
Multiple Scales Method For A Matrix Kdv Equation, Mehmet Naci Özer
Multiple Scales Method For A Matrix Kdv Equation, Mehmet Naci Özer
Turkish Journal of Physics
In this paper the method of multiple scales is used to derive an integrable matrix non-linear Schrödinger equation (MNLS) as an amplitude equation from the Matrix Korteweg-de Vries equation (MKdV) associated with symmetric spaces. Then the integrability of the MNLS equation is deduced by the derivation of the spectral problem for the MNLS equation from the spectral problem for the MKdV equation.
Quantum Integrable Systems Of The Group Su(1, 1), Mehmet Sezgi̇n, Yılmaz Asad Verdi̇yev
Quantum Integrable Systems Of The Group Su(1, 1), Mehmet Sezgi̇n, Yılmaz Asad Verdi̇yev
Turkish Journal of Physics
Quantum integrable systems related with SU(1, 1) group manifold or hyperboloid [x, x] = x^2_1 + x^2_2 - x^2_3 - x^2_4 = 1 in spherical, hyperbolic and parabolic coordinates systems are considered. The explicit expressions for waves functions, spectra and S-matrices are given.
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 …
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 …
Signal Injection With Perceptual Criteria, T. Engi̇n Tuncer
Signal Injection With Perceptual Criteria, T. Engi̇n Tuncer
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a novel method for increasing the coding performance and information transmission capacity is presented. This method is mainly based on perceptual modelling of input signal such as speech or audio. Presented approach may be seen as an alternative to transforms which dynamically change analysis window for better energy compaction. A perceptual model is established in order to obtain a global masking threshold in frequency below which sounds become inaudible. Certain criteria are developed for identifying the signal injection bands. A new multiband filter design method which is a generalization of windowing method is used to separate the …
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 …
Genetic Approach For The Determination Of Object Parameters From X Ray Projections, Tayfun Günel, Sedef Kent
Genetic Approach For The Determination Of Object Parameters From X Ray Projections, Tayfun Günel, Sedef Kent
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a new method is presented, based on genetic algorithms for determining object parameters such as radii and/or attenuation coefficients with some assumptions and estimating a cross-sectional image of an object from its projections obtained by X ray illumination. After it was tested for projections degraded by different random noise levels, it was observed that the genetic and fuzzy genetic algorithms improved the signal to noise ratio of the projections. The fuzzy genetic algorithm gave better results than the genetic algorithm.