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Articles 9001 - 9030 of 10317
Full-Text Articles in Physical Sciences and Mathematics
Sonar And High Resolution Seismic Studies In The Eastern Black Sea, Günay Çi̇fçi̇, Derman Dondurur, Mustafa Ergün
Sonar And High Resolution Seismic Studies In The Eastern Black Sea, Günay Çi̇fçi̇, Derman Dondurur, Mustafa Ergün
Turkish Journal of Earth Sciences
The Black Sea is one of the largest inland seas in the world. Off the shelf, the water depth quickly plunges to an average depth of 2 km. The Black Sea sediments are rich in calcite and organic carbon, the latter showing a high degree of preservation due to anoxia in the waters below 100-150 m. Slope failures and sediment instability related to immense gas and gas hydrate accumulations are serious problems that can lead to the failure of offshore installations. Marine geophysical surveys have been carried out in the Eastern Black Sea basin using state-of the-art technology to produce …
The Ophiolitic Molasse Unit Of Ikaria Island (Greece), Adonis D. Photiades
The Ophiolitic Molasse Unit Of Ikaria Island (Greece), Adonis D. Photiades
Turkish Journal of Earth Sciences
Ikaria Island can be divided generally into two composite tectonic units, namely the lower and upper. The lower unit comprises paragneiss basement with local orthogneiss bodies that is overlain by a platform-type marble sequence, passing upward into a sequence of intercalated schist and marble that is intruded by Miocene granites. The upper unit has not experienced Alpine high-pressure metamorphism, and is restricted to the central (Kefala unit) and northeastern (Faros area) parts of the island, which host ophiolitic associations similar to those found in the upper unit of several Cycladic islands. The Faros area consists of an Oligocene-Early Miocene age …
Upper Cretaceous Stratigraphy Of The Bey Dağları Carbonate Platform, Korkuteli Area (Western Taurides, Turkey), Bi̇lal Sari, Saci̇t Özer
Upper Cretaceous Stratigraphy Of The Bey Dağları Carbonate Platform, Korkuteli Area (Western Taurides, Turkey), Bi̇lal Sari, Saci̇t Özer
Turkish Journal of Earth Sciences
The Upper Cretaceous Korkuteli (Antalya) carbonate sequence of the Bey Dağları autochthonous unit (western Taurides) comprises two formations. The Cenomanian-Santonian Bey Dağları formation lies at the base of this sequence and can be divided into two parts. Neritic part is characterized by platform-type, peritidal limestones and comprises an approximately 600-m-thick sequence that contains two main rudistid horizons corresponding to Cenomanian and early Santonian. The neritic limestones pass gradually upward into the 15-m-thick, middle-upper Santonian massive hemipelagic limestones that form the upper part. The upper Campanian-middle Maastrichtian Akdağ formation consists totally of pelagic limestones that indicate basinal conditions and disconformably overlies …
Obituary, Gülsen Uçarkul, Tuncay Taymaz
Obituary, Gülsen Uçarkul, Tuncay Taymaz
Turkish Journal of Earth Sciences
No abstract provided.
Tectonostratigraphic Evolution Of The North Anatolian Palaeorift (Napr): Hettangian-Aptian Passive Continental Margin Of The Northern Neo-Tethys, Turkey, Ali̇ Koçyi̇ği̇t, Demi̇r Altiner
Tectonostratigraphic Evolution Of The North Anatolian Palaeorift (Napr): Hettangian-Aptian Passive Continental Margin Of The Northern Neo-Tethys, Turkey, Ali̇ Koçyi̇ği̇t, Demi̇r Altiner
Turkish Journal of Earth Sciences
The Jurassic-Early Cretaceous stratigraphical, sedimentological and structural evolutionary history of the northern branch of Neo-Tethys is recorded and preserved within an average 6-km-thick basin fill. The basin fill is well-exposed as discontinuous inliers of varying size and thickness within, and to the north of, the Late Cretaceous-Early Tertiary İzmir-Ankara-Erzincan Suture throughout northern Turkey. This basin fill unconformably overlies a substratum comprising the deformed rock assemblages of the Triassic Karakaya palaeorift and its Hercynian basement. Detailed studies based on geological mapping at a 1/25,000 scale and stratigraphic sections measured at 14 type localities show that this infill includes stratigraphical and sedimentological …
Effects Of Ozonation On Characteristics Of Aquatic Fulvic Acid, Şermi̇n Gül
Effects Of Ozonation On Characteristics Of Aquatic Fulvic Acid, Şermi̇n Gül
Turkish Journal of Chemistry
Aquatic fulvic acid (FA) treated with ozone was characterized by physical/chemical (dissolved organic carbon-DOC), spectroscopic (UV/VIS, IR, fluorescence), chromatographic (gel permeation chromatography-GPC) methods. The influence of ozonation on the subsequent water treatment process such as flocculation and chlorination was also examined. The DOC concentration of the 20 min ozonated FA samples was reduced only a small amount (5%) whereas the UV absorption reduced to a higher percent (40%). The IR spectra of ozonated samples showed a moderate attenuation of the double band and aromatic character of FA. Ozonation of the FA caused the fluorescence intensities to increase steadily with ozonation …
C-Closed Sets In L-Fuzzy Topological Spaces And Some Of Its Applications, Ali̇ Ahmed Nouh
C-Closed Sets In L-Fuzzy Topological Spaces And Some Of Its Applications, Ali̇ Ahmed Nouh
Turkish Journal of Mathematics
We introduce and study the notion of C-closed sets in L-fuzzy topological spaces. Then, C-convergence theory for nets and ideals is established in terms of C-closedness. Finally, we give a new concept of C-continuity on L-fuzzy topological space by means of L-fuzzy C-closedness and investigate some of its properties and its relationships with other L-fuzzy mappings introduced previously. Then we systematically study the characterizations of this notion with the aid of the C-convergence of L-fuzzy nets and L-fuzzy ideals.
Interface Roughness-Induced Intrassubband Scattering In A Quantum Well Under An Electric Field, Guseyn Behbudoglu Ibragimov
Interface Roughness-Induced Intrassubband Scattering In A Quantum Well Under An Electric Field, Guseyn Behbudoglu Ibragimov
Turkish Journal of Physics
The scattering rates in the lowest subband in a quantum well are calculated for interface roughness scattering when an electric field is applied perpendicular to the layer plane. It is found that the interface roughness scattering rate increases with increase in the electric field. The electric field changes the interface roughness scattering rates drastically in thick QWs compared with those for the zero-field case. This behaviour in the scattering rate gives a new degree of freedom in regions of interest in device applications.
Kinetics Of Light-Induced Metastable Defect Creation And Annealing In A-Si:H, Alp Osman Kodolbaş, Aynur Eray, Özcan Öktü
Kinetics Of Light-Induced Metastable Defect Creation And Annealing In A-Si:H, Alp Osman Kodolbaş, Aynur Eray, Özcan Öktü
Turkish Journal of Physics
Constant Photocurrent Method (CPM) and steady state photoconductivity measurements are used to investigate the creation of light-induced metastable defects in a-Si:H at room temperature and their annealing. Light-induced metastable defect concentration N$_{d}$ varies with exposure time t_{e}as t_{e}^{r} with r=0.34\ pm 0.02, as expected from the recombination induced weak bond breaking model [1]. The validity of a stretched exponential model is also studied [2]. From the annealing experiments, the distribution of thermal annealing activation energies is calculated following the method proposed by Hata and Wagner [3]. Defects created at room temperature show a narrow distribution of annealing activation energies peaking …
Filamentation Of Light Emission In An Infrared-Visible Image Converter With A Semiconductor Photodetector, Hi̇lal Yücel Kurt, H. S. Kiymaz, B. G. Salamov, K. Çolakoğlu
Filamentation Of Light Emission In An Infrared-Visible Image Converter With A Semiconductor Photodetector, Hi̇lal Yücel Kurt, H. S. Kiymaz, B. G. Salamov, K. Çolakoğlu
Turkish Journal of Physics
This work studies the light emission patterns associated with the spatial modulation of the transversal distribution of the current density in a converter cell with a GaAs semiconductor cathode. Such light emission exhibits spatial structures of current filaments depending on the feeding voltage, illumination intensity, gas pressure and the surface treatment of the electrodes. When the current is increased above the stable limit, breakdown or small current filamentations begin. However, n-GaAs exhibits an S-shaped current-density-field relation due to impact ionization of carriers from shallow donors into the conduction band under high electric fields. The assessment of the filament formation is …
The B --> S G G Decay In The General Two Higgs Doublet Model, E. O. İltan
The B --> S G G Decay In The General Two Higgs Doublet Model, E. O. İltan
Turkish Journal of Physics
We study the decay width of the inclusive process b --> s g g in the two Higgs doublet model with three-level flavor changing neutral currents (model III). We analyse the dependencies of the differential decay width to the s- quark energy E_s and model III parameters, charged Higgs mass m_H_{^{±}} and Yukawa coupling \bar{\xi}_{N,bb}^D. We observe that there exist a considerable enhancement in the decay width for the relevant process. This enhancement can be reduced by choosing C_7^{eff} as negative or increasing the lower bound of m_H_{^{±}} to the large values. This is an interesting result which gives an …
Two-Dimensional Photonic Crystal L-Shaped Bent Waveguide And Its Application To Wavelength Multi/Demultiplexer, Yoshihiro Naka, Hiroyoshi Ikuno
Two-Dimensional Photonic Crystal L-Shaped Bent Waveguide And Its Application To Wavelength Multi/Demultiplexer, Yoshihiro Naka, Hiroyoshi Ikuno
Turkish Journal of Electrical Engineering and Computer Sciences
The bent waveguide is a key element for integrated optical signal processing waveguide devices. We propose a new type of two-dimensional photonic crystal L-shaped bent waveguides with additional pillars at the corner. Using the FDTD method based on the principle of multidimensional wave digital filters we simulate its transmission characteristics and show an excellent transmission of light in L-shaped bent waveguide. As an application we design compact size multi/demultiplexer composed of the L-shaped bent waveguides and directional couplers and realize multi/demultiplexer with low-insertion loss and high extinction ratio device whose size is of the order of the wavelength of light.
The Role Of Crustal Fluids In Strike-Slip Tectonics: New Insights From Magnetotelluric Studies, Martyn Unsworth
The Role Of Crustal Fluids In Strike-Slip Tectonics: New Insights From Magnetotelluric Studies, Martyn Unsworth
Turkish Journal of Earth Sciences
The presence of fluids in the Earth's crust can dramatically change the rheology and may control a wide range of tectonic processes, especially in regions characterized by strike-slip deformation. Fluids such as water and partial melt change the electrical resistivity of the subsurface and may be detected through geophysical techniques that remotely sense electrical resistivity. For imaging to crustal and upper mantle depths, the most useful technique is magnetotellurics (MT) that uses natural electromagnetic waves as an energy source. Magnetotelluric studies of the Tibetan Plateau have detected a widespread mid-crustal layer of partial melting across almost the entire north-south extent …
N-Commutator Groups, A. A. Mehrvarz, K. Azizi
N-Commutator Groups, A. A. Mehrvarz, K. Azizi
Turkish Journal of Mathematics
A sufficient condition such that any element of G' (the commutator subgroup of G) can be represented as a product of n commutators, was studied in \cite{GAL62}. In this article we study a necessary and sufficient condition such that any element of G' can be represented as a product of n commutators, Let n be the smallest nature number such that any element of finite group G can be represented as a product of n commutators. A group G with this property will be called an n -commutator group, and n will be denoted by c(G) . Then \frac{\ln( G' …
A Macwilliams Type Identity, İrfan Şi̇ap
A Macwilliams Type Identity, İrfan Şi̇ap
Turkish Journal of Mathematics
A MacWilliams identity for a \rho complete weight enumerator of linear spaces of matrices with entries from the ring F_q[u]/(u^r-a), where a \in F_q, endowed with a non-Hamming metric is proved.
The Sensitivity Of C\Rightarrow U \Gamma Decay In The Gluino-Axion Model, Müge Boz
The Sensitivity Of C\Rightarrow U \Gamma Decay In The Gluino-Axion Model, Müge Boz
Turkish Journal of Physics
The sensitivity of c\rightarrow u \gamma decay in the recently proposed gluino-axion model is analyzed for a light sbottom in a restricted parameter space. The decay rate enhances up to 3\%$ with respect to the SM result in a moderate range of \tan\beta values.
Schrödinger Quantization And Excited States Of Zitterbewegung, Selahatti̇n Gönen, Ali̇ Havare
Schrödinger Quantization And Excited States Of Zitterbewegung, Selahatti̇n Gönen, Ali̇ Havare
Turkish Journal of Physics
General wavefunction is expanded as power series of a variable which describes internal dynamics of particle, to show that it contains excited states of Schrödinger's Zitterbewegung.
Preparation And Anisotropic Elastic Property Of Bi-Sr-Ca-Cu-O Whiskers, Khaliq A. Chaudhary, M. Arshad Choudhry
Preparation And Anisotropic Elastic Property Of Bi-Sr-Ca-Cu-O Whiskers, Khaliq A. Chaudhary, M. Arshad Choudhry
Turkish Journal of Physics
Flexible and superconducting Bi-Sr-Ca-Cu-O whiskers have been prepared by sintering the melt-quenched glassy powder at 830^oC in oxygen atmosphere. X-ray diffraction and a.c. susceptibility measurements reveal that the whiskers belong to 2212 phase with T_{c} = 79k. The whiskers possess high strength and flexibility along c-axis but were found to be weak and brittle when bent normal to the c-axis. The anisotropic micromechanical elastic property of the whiskers have been demonstrated under a low power optical microscope.
Radial And Nonradial Oscillations Of 63 Her (Hd155514 = Hr6391), Ri̇kkat Ci̇velek, Ni̇lgün Kiziloğlu, Hali̇l Kirbiyik
Radial And Nonradial Oscillations Of 63 Her (Hd155514 = Hr6391), Ri̇kkat Ci̇velek, Ni̇lgün Kiziloğlu, Hali̇l Kirbiyik
Turkish Journal of Physics
An attempt has been made toward explaining the observed frequencies in 63 Her. A sequence of evolutionary models have been calculated up to a point where stellar parameters match the observed luminosity and effective temperature of 63 Her. Radial and nonradial oscillations frequencies were obtained for a series of masses 1.85, 1.90 and 1.95 M_\odot and eigth models which represent best the pulsations of 63 Her are given in this paper. Calculations are restricted to low harmonic degrees ( l= 0,1,2,3 ). Six of the eigth observed frequencies quoted in literature were obtained. These we obtained for the model of …
Tsl-Epr Correlation Study Of Lapo_4 : Ce, Tb, B. S. Chakrabarty, K. V. R. Murthy, T. R. Joshi
Tsl-Epr Correlation Study Of Lapo_4 : Ce, Tb, B. S. Chakrabarty, K. V. R. Murthy, T. R. Joshi
Turkish Journal of Physics
Gamma irradiated TSL glow curves of laboratory made phosphor samples of LaPO_{4}:Ce, Tb exhibited one intense peak around 408 K and two smaller peaks around 508 K and 613 K. The spectrum of the first glow peak gives spectral peaks around 480 nm and 540 nm, which can be attributed to the thermal destruction of F^{++} centres and PO_4^{2-} radicals. The luminescense centre has been thought to be Cerium and Terbium ions. The glow peak around 413 K for UV irradiated samples has been attributed to aggregates of dopant ions. The photoluminescence study of the samples exhibited one intense peak …
Investigation Of The Critical Current Density Of Ybacuo High-Temperature Superconductor Ceramic, Ioseb R. Metskhvarishvili, Nodar P. Kekelidze, Magda R. Metskhvarishvili
Investigation Of The Critical Current Density Of Ybacuo High-Temperature Superconductor Ceramic, Ioseb R. Metskhvarishvili, Nodar P. Kekelidze, Magda R. Metskhvarishvili
Turkish Journal of Physics
The method of high harmonics is used to investigate penetration of low magnetic fields within the Y_{1}Ba_{2}Cu_{3}O_{7} high-temperature superconductor ceramic. Given experimental results are explained by the modal dependencies between the value of critical current density and the magnetic induction B: j_{c}(B) = j_{c}(0){\frac{{B_{0}^{2}}} {{B_{0}^{2} + B^{2}}}}.
Dispersion Analysis Of Sns And Snse, Haluk Şafak, Mustafa Merdan, Ö. Faruk Yüksel
Dispersion Analysis Of Sns And Snse, Haluk Şafak, Mustafa Merdan, Ö. Faruk Yüksel
Turkish Journal of Physics
The reflectance spectra of single crystals of SnS and SnSe were measured at normal incidence by unpolarized light. The refractive indices of speciemens were calculated by Kramers-Kronig Analysis. On the basis of the Wemple diDomenico single oscillator model, the dispersion parameters were determined. It is found that the parameters obtained by unpolarized light are, in general close to those reported for polarized cases. Morever, a close similarity were observed with E//b polarization for SnS.
Free-Carrier Absorption In Quantum Well Structures For Alloy-Disorder Scattering, Guseyn Behbudoglu Ibragimov
Free-Carrier Absorption In Quantum Well Structures For Alloy-Disorder Scattering, Guseyn Behbudoglu Ibragimov
Turkish Journal of Physics
A free-carrier absorption theory is given for quantum wells structures in III-V semiconducting materials, for the case when the carriers a scattered by alloy-disorder. It is found that absorption coefficients due to alloy-disorder and to phonons are of the same order. Results are shown that the absorption coefficient decreases with increasing photon frequency and increases with increasing temperature. It is also shown that the absorption coefficient increases with decreasing layer thickness. We also found that absorption in quantum wells structures is enhanced by going to quantum wells of smaller thickness over its value in the bulk III-V semiconducting materials.
The Effects Of Nonstoichiometry In High - T_C Superconducting Properties Of Yba_2cu_{3 + X}O_{7 - \Delta}, Beniah Ndudim Onwuagba
The Effects Of Nonstoichiometry In High - T_C Superconducting Properties Of Yba_2cu_{3 + X}O_{7 - \Delta}, Beniah Ndudim Onwuagba
Turkish Journal of Physics
Polycrystalline samples of high T_c superconductor YBa_2Cu_{3 + x}O_{7 - \delta} with 0 \leqslant x \leqslant 0.5 were grown. The effects of nonstoichiometry on the resistance slope above transition temperature T_c and X-ray diffraction patterns for these samples were investigated. In the diffraction patterns obtained, apart from some new features in the peaks, these polycrystalline samples show predominantly 123 phase.
Numerical Solution And Convergence Speed Of Variational Formulation For Linear Schrödinger Equation, Murat Subaşi, Bünyami̇n Yildiz
Numerical Solution And Convergence Speed Of Variational Formulation For Linear Schrödinger Equation, Murat Subaşi, Bünyami̇n Yildiz
Turkish Journal of Mathematics
This paper presents a numerical solution of an optimal control problem for linear parabolic equations. The estimates for the error of the difference scheme and the speed of convergence have been established. Numerical results are reported on test problems.
On Summand Sum And Summand Intersection Property Of Modules, Mustafa Alkan, Abdullah Harmanci
On Summand Sum And Summand Intersection Property Of Modules, Mustafa Alkan, Abdullah Harmanci
Turkish Journal of Mathematics
R will be an associative ring with identity and modules M will be unital left R- modules. In this work, extending modules and lifting modules with the SSP (or SIP) are studied. A necessary and sufficient condition for a module M to have the SSP is that for every decomposition M = A\oplus B and f\in Hom(A,B), Im(f) is a direct summand of B. Among others it is shown also that a (C_3) module with the SIP has the SSP, and a (D_3) module with SSP has the SIP.
Asymptotic Formulas For The Eigenvalues Of The Schrodinger Operator, Şi̇ri̇n Atilgan, Sedef Karakiliç, Oktay A. Veliev
Asymptotic Formulas For The Eigenvalues Of The Schrodinger Operator, Şi̇ri̇n Atilgan, Sedef Karakiliç, Oktay A. Veliev
Turkish Journal of Mathematics
In this paper, we obtain asymptotic formulas for the eigenvalues of the d-dimensional Schrodinger operator L=-\Delta +q(x) in d-dimensional parallelepiped F with Dirichlet and Neumann boundary conditions.
Remarks On Bounded Operators In Köthe Spaces, P. B. Djakov, T. Terzi̇oğlu, M. Yurdakul, V. P. Zahariuta
Remarks On Bounded Operators In Köthe Spaces, P. B. Djakov, T. Terzi̇oğlu, M. Yurdakul, V. P. Zahariuta
Turkish Journal of Mathematics
We prove that if \lambda(A),\lambda(B) and \lambda(C) are Köthe spaces such that L(\lambda(A),\lambda(B)) and L(\lambda(C),\lambda(A)) consist of bounded operators then each operator acting on \lambda(A) that factors over \lambda(B)\widehat\otimes_{\pi} \lambda(C) is bounded.
Novel Method For The Spectrophotometric Determination Of Isoniazid And Ritodrine Hydrochloride, Padmarajaiah Nagaraja, Kallanchira Sunitha, Ramanathapura Vasantha, Hemmige Yathirajan
Novel Method For The Spectrophotometric Determination Of Isoniazid And Ritodrine Hydrochloride, Padmarajaiah Nagaraja, Kallanchira Sunitha, Ramanathapura Vasantha, Hemmige Yathirajan
Turkish Journal of Chemistry
A simple, rapid and sensitive spectrophotometric method for the determination of isoniazid (INH) and ritodrine hydrochloride (RTH) in pure form as well as dosage forms is described. The method is based on the diazotisation of 4,4'-sulphonyldianiline (dapsone, DAP) followed by a coupling reaction with either INH or RTH in sodium hydroxide medium. Beer's law is obeyed in the concentration range of 0.5-20 \mu g ml^{-1} for INH at 440 nm and 0.5-18 \mu g ml^{-1} for RTH at 460 nm. The method is successfully employed for the determination of INH/RTH in pharmaceutical preparations and the results agree favourably with the …
Determination Of The Micropore Structures Of Activated Carbons By Adsorption Of Various Dyestuffs From Aqueous Solution, Fuat Güzel, İlhan Uzun
Determination Of The Micropore Structures Of Activated Carbons By Adsorption Of Various Dyestuffs From Aqueous Solution, Fuat Güzel, İlhan Uzun
Turkish Journal of Chemistry
In this study, some activated carbons prepared from sour cherry pits under various conditions were investigated. For comparison purposes, the commercial activated carbons Merck-2514 and Merck-2184 were used. The nitrogen adsorption isotherms at 77 K were used as reference for comparison, while p-nitrophenol, methylene blue, orange-II and victoria blue adsorptions were determined from aqueous solution at 298 K. It was clear from the specific surface area values obtained that the best activated carbon was obtained by activation for 4 hours following the chemical activation. Its adsorption properties are closer to the levels of the Merck commercial carbons. It was concluded …