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- 2e) (1)
- 73.50.Pz; 72.80.Ng;/photovoltaic effects; amorphous thin films; built-in potentials (1)
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- A. Optical transmission; B. Refractive index; C. Swanepoel method D. Hydrogenated amorphous silicon nitride (1)
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Articles 1 - 30 of 65
Full-Text Articles in Physical Sciences and Mathematics
Field And Polarization Effects Arising In Neutrino-Lepton Processes In A Magnetic Field, V. A. Gusseinov
Field And Polarization Effects Arising In Neutrino-Lepton Processes In A Magnetic Field, V. A. Gusseinov
Turkish Journal of Physics
We discuss the effects arising in the neutrino-lepton processes (\nu_{\mu}+e^{-} \rightarrow \nu_{e}+\mu^{-} and \overline{\nu}_{e}+e^{-}\rightarrow\overline{\nu}_{\mu}+\mu^{-}) in a constant uniform magnetic field in the framework of the Weinberg-Salam-Glashow model. It is shown that in the case of a superstrong magnetic field and for the muon producing on the ground Landau level the leading term of the cross section asymptotics of the \nu_{\mu}-process does not depend on the field intensity and it effectively describes the one-dimensional free process. In the \nu_{\mu}-process the muons with the spins oriented opposite to the direction of the field are mostly produced. The electrons with the spins oriented …
Is There An Age Of The Universe Problem After The Hipparcos Data?, Murat Özer
Is There An Age Of The Universe Problem After The Hipparcos Data?, Murat Özer
Turkish Journal of Physics
We have reanalyzed the age of the universe problem under the assumption that the lower limit on the age of the globular clusters is \sim11 Gyr, as predicted by the recent Hipparcos data. We find that the globular cluster and the expansion ages in a standard \lambda=0 universe are consistent only if the present value H_0 of the Hubble constant is \leq 60{\rm kms}^{-1}Mpc^{-1}. If H_0>60{\rm kms}^{-1}Mpc^{-1} some kind of modification of the standard \lambda=0 model is required. Invoking a (time-independent) cosmological term \lambda in the Einstein field equations, as has been done frequently before, we have found that …
Magnetoresistance Measurements On Electrodeposited Co_X Cu_{1-X} Alloy Films, Ömer F. Bakkaloğlu, İsmai̇l H. Karahan
Magnetoresistance Measurements On Electrodeposited Co_X Cu_{1-X} Alloy Films, Ömer F. Bakkaloğlu, İsmai̇l H. Karahan
Turkish Journal of Physics
Co_x Cu_{1-x} alloy films were prepared by using electrodeposition technique. The variations of Co and Cu contents of the films were investigated as functions of bath pH and Co content. The compositions of the alloy films were determined using an atomic absorption spectrophotometer. The crystal structures of the alloy films were analyzed using a Cu (K \alpha )-X-ray diffractometer. The diffraction lines observed were only those of copper component in the alloy films. All three films showed negative magnetoresistance and a giant magnetoresistance effect on the order of 1% in Co_{0.26} Cu_{0.74} and 1.7% in Co_{0.19} Cu_{0.81} alloy films at …
A Novel Technique For The Preparation Of Textured Yba_{2}Cu_{3}O_{7-\Delta} Superconductor, Naheed Kouser, Saadat Anwar Siddiqi, Asghari Maqsood
A Novel Technique For The Preparation Of Textured Yba_{2}Cu_{3}O_{7-\Delta} Superconductor, Naheed Kouser, Saadat Anwar Siddiqi, Asghari Maqsood
Turkish Journal of Physics
Textured samples having composition of YBa_{2}Cu_{3}O_{7-\delta} were prepared by using a novel technique of heating the samples in a thermal gradient which varies linearly between 930-950 ^oC over a distance of 5 cm. The samples were characterized by X-ray powder diffraction analysis, temperature dependent resistivity and magnetic susceptibility measurements, and scanning electron microscopy. XRD analysis shows that sample heated between 930-935 ^oC has tetragonal symmetry and all other three samples show orthorhombic symmetry. Samples heated in temperature gradient of 935-945 ^oC aligned along the c-axis. The orthorhombic samples exhibited zero resistance above 86K with short transition width and samples heated …
Zeros Of Scattering Amplitude For A Spin-Dependent Gaussian Potential, Nilufar Farhat Hossain, Hasna Banu, A. K. Halder
Zeros Of Scattering Amplitude For A Spin-Dependent Gaussian Potential, Nilufar Farhat Hossain, Hasna Banu, A. K. Halder
Turkish Journal of Physics
In the proposed model, polarization in the scattering amplitude for a Gaussian potential including spin is considered. The problem of scattering amplitude is formulated in two different ways: the first and second Born approximations along with their high energy limits and the eikonal approximation including Wallace corrections. A comparison of the numerical zeros of the scattering amplitude computed in the above two approximations is studied in the complex momentum transfer plane. An analysis of the zero trajectories shows that the contribution of the spin part in the potential is quite significant at high energies whereas at low energies the spin-part …
Beta Spectrometers With Surface Barrier Detector And Plastic Scintillator: Applications To ^{90}Sr,^{204}Tl,^{210}Pb And ^{14}C, Cüneyt Çeli̇ktaş
Beta Spectrometers With Surface Barrier Detector And Plastic Scintillator: Applications To ^{90}Sr,^{204}Tl,^{210}Pb And ^{14}C, Cüneyt Çeli̇ktaş
Turkish Journal of Physics
In this work, a comparison of responses between a spectrometer using Si Surface Barrier Detector (Si SBD) and a spectrometer using Plastic Scintillator (PS) is given. Experimental pulse height spectra of beta particles from ^{90}Sr,^{204}Tl,^{210}Pb and ^{14}C pure beta sources has been obtained separately. By comparing obtained spectra, the priority of obtaining the beta spectra among them is discussed. This work is related to the spectral response of beta spectrometers to pure beta sources.
Features Of The Compound Multiplicity Of The Interactions Of ^{24}Mg And ^{28}Si Ions With Emulsion Nuclei At 4.5a Gev/C, N. N. Abd-Allah, M. Mohery
Features Of The Compound Multiplicity Of The Interactions Of ^{24}Mg And ^{28}Si Ions With Emulsion Nuclei At 4.5a Gev/C, N. N. Abd-Allah, M. Mohery
Turkish Journal of Physics
The present paper deals with the interactions of ^{24}Mg and ^{28}Si nuclei at 4.5A GeV/c with emulsion. Some characteristics of the compound multiplicity given by the numerical sum of grey and shower particles have been investigated. The obtained results indicate that the compound multiplicity distribution is consistent with KNO-Scaling and its width increases with the size of the projectile nucleus.The dependence of the average compound multiplicity on the numbers of black and the grey particles and the sum of them is obvious and the values of the slope has been found to be independent of the projectile nucleus.
Path Integral Treatment For Spinless Relativistic Equation In The Two Component Theory, M. Merad, T. Boudjedaa, Lyazid Chetouani
Path Integral Treatment For Spinless Relativistic Equation In The Two Component Theory, M. Merad, T. Boudjedaa, Lyazid Chetouani
Turkish Journal of Physics
In this paper we have set up a path integral formalism for Feshbach-Villars equation by using the fermionic Schwinger model for Pauli matrices which describe an isocharge symmetry. This choice is made in analogy with spin model and the coherent state representation is then used. We have also given a general method of treating the problem of vanishing scalar potential by reducing it the to non-relativistic case and then, via Foldy-Wouthuysen canonical transformation, an explicit solution is constructed. The free case and constant magnetic field interaction are explicitly exposed. In each cases the propagators are evaluated and the energy spectrum …
Schrödinger Equation Solutions For Small R And Resulting Functional Relations, Harry A. Mavromatis
Schrödinger Equation Solutions For Small R And Resulting Functional Relations, Harry A. Mavromatis
Turkish Journal of Physics
The Schrödinger equation is examined for small r (i.e. one step beyond the limit r \rightarrow 0) for the cases V(r) \rightarrow r^k, (k>0), and V(r) \rightarrow r^{-k} (0
Calculation Of The Potential And Electric Flux Lines For Parallel Plate Capacitors With Symmetrically Placed Equal Lengths By Using The Method Of Conformal Mapping, Erhan Albayrak
Turkish Journal of Physics
The classical problem of the parallel-plate capacitors has been investigated by a number of authors, including Love [1], Langton [2] and Lin [3]. In this paper, the exact equipotentials and electric flux lines of symmetrically placed two thin conducting plates are obtained using the Schwarz- Cristoffel transformation and the method of conformal mapping. The coordinates x , y in the z-plane corresponding to the constant electric flux lines and equipotential lines are obtained after very detailed and cumbersome calculations. The complete field distribution is given by constructing the family of lines of electric flux and equipotential.
Viscous Dissipation Of Magnetosonic Waves In Solar Corona, Belinda Kalomeni, D. Özlem Hürkal, E. Rennan Pekünlü, Kadri̇ Yakut
Viscous Dissipation Of Magnetosonic Waves In Solar Corona, Belinda Kalomeni, D. Özlem Hürkal, E. Rennan Pekünlü, Kadri̇ Yakut
Turkish Journal of Physics
Wave propagation and dissipation of magnetosonic waves are considered in an inhomogenous viscous coronal plasma permeated by a spatially varying magnetic field. In the linear magnetohydrodynamic approximation the dispersion relation yields two wave modes, fast and slow respectively. Depending on the physical parameters of the medium the damping length scales of the modes show varying behaviours. Damping length scales of the modes show sudden decrease at relevant heights. These drops may be due to phase mixing and resonance absorption. Wave flux density of the magnetosonic waves turns out to be of the order of 10^6 erg cm^{-2} s^{-1}. This is …
Optical Transmission Measurements On Glow-Discharge Amorphous Silicon Nitride Films, İlker Ay, Hüseyi̇n Tolunay
Optical Transmission Measurements On Glow-Discharge Amorphous Silicon Nitride Films, İlker Ay, Hüseyi̇n Tolunay
Turkish Journal of Physics
Hydrogenated amorphous silicon nitride films have been prepared by the glow-discharge decomposition of ammonia/silane gas mixture. From optical transmission measurements in the wavelength range from 400 nm to 1100 nm refractive indices absorption coefficients and optical Tauc gaps of the films have been obtained. A systematic investigation of optical parameters has been carried out as a function of the nitrogen content of samples.
The Temperature Dependence Of Dark Conductivity In Hydrogenated Amorphous Sin_X Films, Hüseyi̇n Tolunay, İlker Ay
The Temperature Dependence Of Dark Conductivity In Hydrogenated Amorphous Sin_X Films, Hüseyi̇n Tolunay, İlker Ay
Turkish Journal of Physics
Thin film samples of hydrogenated amorphous silicon nitride with varying nitrogen content were prepared by conventional plasma deposition from a mixture of SiH_4 and NH_3 . The dark conductivity (\sigma_d) of the films have been measured in the temperature range 420 K - 100 K. The conductivity is thermally activated with a single activation energy down to 250 K and conduction is dominated by electrons in extended states. A strong decrease is observed sigma _d when the nitrogen content is increased.
Study Of Slip Systems In Epidote Single Crystal, Salah-Ud Din, Munnawar Ahmad, Shahzad Chishti
Study Of Slip Systems In Epidote Single Crystal, Salah-Ud Din, Munnawar Ahmad, Shahzad Chishti
Turkish Journal of Physics
Measurements of microhardness anisotropy by Knoop diamond indentations on the prismatic (100) planes of epidote crystals, point group 2/m and space group P21/m, show that microhardness is determined by crystallographic slip on the (100) systems. Microhardness anisotropy is explained in terms of the effective resolved shear stress distribution in these slip systems.
Computation Of Overlap, Kinetic And Nuclear Attraction Integrals By A Novel Method, Gökhan Budak, Abdulhali̇k Karabulut, Lütfü Demi̇r, Nagi̇f Sefteroğlu Nabi̇yev, Yusuf Şahi̇n
Computation Of Overlap, Kinetic And Nuclear Attraction Integrals By A Novel Method, Gökhan Budak, Abdulhali̇k Karabulut, Lütfü Demi̇r, Nagi̇f Sefteroğlu Nabi̇yev, Yusuf Şahi̇n
Turkish Journal of Physics
A new way of computing overlap, kinetic and nuclear attraction integrals over Slater functions by means of optimized Gaussian expansion is proposed. This article is concerned with the construction of the general algorithm for evaluating the three integrals. These integral formulae presented in the form of a series whose terms are the analytical function of inter-atomic distances. In the present method, unlike many other popular methods, the numerical integration procedure is unnecessary since it does not contain the incomplete gamma function. The present scheme has been programmed in standard Fortran-77 and tested for various orbitals. The result of the calculation …
Some String Cosmological Models In Cylindrically Symmetric Inhomogeneous Universe, Hüsnü Baysal, İlhami̇ Yavuz, İsmai̇l Tarhan, Uğur Camci, İshan Yilmaz
Some String Cosmological Models In Cylindrically Symmetric Inhomogeneous Universe, Hüsnü Baysal, İlhami̇ Yavuz, İsmai̇l Tarhan, Uğur Camci, İshan Yilmaz
Turkish Journal of Physics
The aim of this paper is to investigate the behavior of a string in the cylindrically symmetric inhomogeneous cosmological model. It has been assumed that expansion \theta in the model is proportional to \sigma^1_1 of the eigenvalue of the shear tensor \sigma^{\mu}_{\nu}. Also, various physical and geometrical properties of the model have been discussed.
Photospheric Line Profiles In Deneb (A2 Iae), Berahi̇tdi̇n Albayrak, Cemal Aydin, Dursun Koçer
Photospheric Line Profiles In Deneb (A2 Iae), Berahi̇tdi̇n Albayrak, Cemal Aydin, Dursun Koçer
Turkish Journal of Physics
In this study, the strong lines were examined to determine the effect of velocity gradient due to mass loss on the line profiles in the atmosphere of Deneb. The lines are formed in the optical depth range -1.14 < log \tau < -0.14. None were found to exibit any asymmetry.
A Theoretical Model For The Non-Linear Susceptibility Of The Antiferromagnetic Systems, Beki̇r Özçeli̇k, Keri̇m Kiymaç, Ahmet Eki̇ci̇bi̇l
A Theoretical Model For The Non-Linear Susceptibility Of The Antiferromagnetic Systems, Beki̇r Özçeli̇k, Keri̇m Kiymaç, Ahmet Eki̇ci̇bi̇l
Turkish Journal of Physics
In this study, we have developed a general theoretical model, based upon the simple mean field model of N\'{e}el, for the non-linear response of an antiferromagnetic system. The results indicate that the odd order derivatives, (d^{2n + 1}m_{a})_{0} = (-d^{2n + 1}m_{b})_{0}, where n=1,2,3......, will diverge and the even order derivatives, (d^{2n}m_{a})_{0} = (d^{2n}m_{b})_{0} will vanish due to the symmetry of two sublattices, ``a'' and ``b'', forming the antiferromagnet. This model also supports our experimental results performed on two antiferromagnetic samples, namely, Cs_{2}MnCl_{4}.2H_{2}O and MnCl_{2}.4H_{2}O [1].
Exciton Investigations And The Urbach Tails Of Gd Doped And Undoped Gase, Beki̇r Gürbulak
Exciton Investigations And The Urbach Tails Of Gd Doped And Undoped Gase, Beki̇r Gürbulak
Turkish Journal of Physics
Absorption measurements were carried out in GaSe and GaSe:Gd samples in temperature range 10-320 K in steps 10 K. The first and the second (n=1 and n=2) excitonic levels were marked. The first exciton energies for n=1 were calculated as 2.118, 2.008 eV in GaSe, and 2.125, 2.006 eV in GaSe:Gd at 10, 320 K and respectively. The second exciton energies for n=2 were calculated as 2.140, 2.125 eV in GaSe at 10, 80 K and 2.141, 2.120 eV in GaSe:Gd at 10, 120 K and respectively. Binding energies of GaSe and GaSe:Gd were calculated as (29.46\pm 1 and 21.33\pm …
Lattice Dynamical Calculations For The Co-Fe Alloys, Kemal Çolakoğlu, Yasemi̇n Özteki̇n Çi̇ftçi̇
Lattice Dynamical Calculations For The Co-Fe Alloys, Kemal Çolakoğlu, Yasemi̇n Özteki̇n Çi̇ftçi̇
Turkish Journal of Physics
Lattice dynamical calculations are performed on Co_{0.92}-Fe_{0.08} alloy with fcc structure. The de Launay Angular force (DAF) model is used to represent the ion-ion intreactions, and the long-range ion-electron interactions are accounted for along the lines of the Sharma-Joshi scheme. The frequency distribution and the lattice specific heat are also computed for the studied alloys. The present theoretical results are in reasonable agreement with the available experimental data.
Second Order Elastic Constants And Some Thermoelastic Properties Of Alkali Halides Using Woodcock Potential, Harun Reşi̇t Yazar, Sedat Ağan, Kemal Çolakoğlu
Second Order Elastic Constants And Some Thermoelastic Properties Of Alkali Halides Using Woodcock Potential, Harun Reşi̇t Yazar, Sedat Ağan, Kemal Çolakoğlu
Turkish Journal of Physics
Second Order Elastic Constants (S.O.E.C) of NaCl-type crystals have been calculated using the Woodcock potential. Short-range repulsive interactions have been included up to second-nearest neighbors. This potential form represents the composite form of the inverse power dependence and exponential dependence of the repulsive energy on interionic distance. Some thermoelastic and thermodynamic properties such as Anderson-Grüneisen parameters \delta _{T}, and \delta _{S}, Volume thermal expansion coefficient \beta and Grüneisen gama \gamma _{G} have been calculated in terms of calculated values of S.O.E.C and Third Order Elastic Constant ( T.O.E.C).
Computational Study For The Structural Change Of The System Cdte_{1-X} S_X Thin Film, Emad Khdayer Al-Shakarchi
Computational Study For The Structural Change Of The System Cdte_{1-X} S_X Thin Film, Emad Khdayer Al-Shakarchi
Turkish Journal of Physics
Polycrystalline thin film of the graded system CdTe_{1-x}S_{x} for x=0,0.1,\ldots,1 are prepared by using thermal evaporation technique deposited on the glass substrate with an average thickness 3000 Å for each individual value of x . XRD technique is used with the aid of a computational program to study the phase change from cubic zinc blend structure to hexagonal wurtzite with an inversion point related to the x-value. It is found that x=0.1 gives us an inversion point in the structural change from cubic to hexagonal phase.
The Lattice Dynamics And The Elastic Behaviour Of Fcc And Bcc Ba, Yasemi̇n Özteki̇n Çi̇ftçi̇, Kemal Çolakoğlu
The Lattice Dynamics And The Elastic Behaviour Of Fcc And Bcc Ba, Yasemi̇n Özteki̇n Çi̇ftçi̇, Kemal Çolakoğlu
Turkish Journal of Physics
The two-body pairwise E.G.E.P. (Extended Generalized Exponantial Potential) type Morse potential and volume dependent energy are assumed to represent the total energy of the Ba crystal. The parametrized potential is used to calculate the second- and third-order elastic constants C_{ij} and C_{ijk}, pressure derivatives of bulk moduli and Grüneisen parameter \gamma . The phonon frequencies are also computed and plotted. The obtained results are compared with available experimental data and, in general, the agreement is good.
Iba-1 Calculations Of E2/M1 Mixing Ratios And Quadrupole Moments In ^{154}Gd, Mehmet Baylan
Iba-1 Calculations Of E2/M1 Mixing Ratios And Quadrupole Moments In ^{154}Gd, Mehmet Baylan
Turkish Journal of Physics
In this study the Interacting Boson Approximation is applied in its basic form (IBA-1) to the calculation of gamma-ray E2/M1 multipole mixing ratios and quadrupole moments [Q( 2^{+} )] of electromagnetic transitions in ^{154}Gd. The numerical results obtained for ^{154}Gd are in reasanably good agreement with previous experimental and theoretical values.
Built-In Potential Measurements In A-Si:H P-I-N Solar Cells, Ruhi̇ Kaplan, Bengü Kaplan
Built-In Potential Measurements In A-Si:H P-I-N Solar Cells, Ruhi̇ Kaplan, Bengü Kaplan
Turkish Journal of Physics
We have measured the open-circuit voltage V_{oc} and the short-circuit current density J_{sc} of amorphous silicon (a-Si:H) p-i-n solar cells deposited by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) at different monochromatic illuminations, and temperatures. From the measurements, the built-in potential V_{bi} was determined by using two different methods: activation energy and differential temperature. The results from both methods were analyzed and compared as a function of excitation wavelength. It was observed that there is good agreement between the two methods. We found that V_{bi} increases until about 650 nm, and then decreases with increasing wavelength. This behaviour is explained and …
Space Charge Limited Current At High Fields In Al-Ge-Al Surface Barrier Devices, A. I. Mukolu
Space Charge Limited Current At High Fields In Al-Ge-Al Surface Barrier Devices, A. I. Mukolu
Turkish Journal of Physics
The current-voltage (I-V) characteristics of Aluminium-Germanium-Aluminium (Al-Ge-Al) surface barrier devices at different fields (
Coproduct Of Su_{Q} (2), Coherent States And Four Point Function With Logarithmic Regge Trajectories, M. Arik, Ayşe Peker-Dobie
Coproduct Of Su_{Q} (2), Coherent States And Four Point Function With Logarithmic Regge Trajectories, M. Arik, Ayşe Peker-Dobie
Turkish Journal of Physics
The representation of the operators belonging to a 2 \times 2 SU_q (2) matrix yield a Hilbert space H. The coproducts of these operators define a Hilbert space H^{(2)} isomorphic to H and canonically embedded in H \otimes H. The four-point function obtained by taking the scalar product of the ground state of H^{(2)} with the coherent states in H \otimes H is uniquely defined, is meromorphic and has Regge behaviour.
Null String In Curved Backgrounds, Sergey Nikolaevich Roshchupkin
Null String In Curved Backgrounds, Sergey Nikolaevich Roshchupkin
Turkish Journal of Physics
We consider null string in curved backgrounds. Some exact solutions of the classical equations of motion and of the constraints for the null string in a large class of cosmological backgrounds are found.
On The Evaluation Of Determinantal Wave Functions In Open-Shell Hartree-Fock Theory, I. I. Guseinov, Ramazan Demi̇r
On The Evaluation Of Determinantal Wave Functions In Open-Shell Hartree-Fock Theory, I. I. Guseinov, Ramazan Demi̇r
Turkish Journal of Physics
Slater method is modified for the evaluation of determinantal wave functions appearing in open-shell Hartree-Fock (HF) theory [1]. Using modified Slater method we have calculated, as an example, the orbital energies and the wave functions of terms obtained from the electronic configuration of a ground state of an N-atom system in the Hartree-Fock-Roothaan (HFR) approximation. The modified determinantal method introduced in this paper can be of considerable help and importance in the simplification and calculation of atomic and molecular electronic structure.
Excitation Plus Ionization In Electron-Atom Collisions To He^{+} (N=2): (E,2e), (E, E\Gamma ) And (E, 2e\Gamma ) Studies, Mevlut Dogan, Albert Crowe
Excitation Plus Ionization In Electron-Atom Collisions To He^{+} (N=2): (E,2e), (E, E\Gamma ) And (E, 2e\Gamma ) Studies, Mevlut Dogan, Albert Crowe
Turkish Journal of Physics
Simultaneous excitation-ionization of helium atoms by electron impact is observed by the coincidence detection of the outgoing particles. The relationship between (e,2e), (e,e\gamma ) and (e,2e\gamma ) experiments is discussed.