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Articles 8431 - 8460 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Calorimetric Studies On Se_{0.68}Ge_{0.22}M_{0.10} (M = Cd, In, Pb) Chalcogenide Glasses, N. Mehta, P. Agarwal, A. Kumar
Calorimetric Studies On Se_{0.68}Ge_{0.22}M_{0.10} (M = Cd, In, Pb) Chalcogenide Glasses, N. Mehta, P. Agarwal, A. Kumar
Turkish Journal of Physics
Differential scanning calorimetry (DSC) is performed at different heating rates under non-isothermal conditions to calculate the activation energy of crystallization E_c for chalcogenide glasses Se_{0.68}Ge_{0.22}M_{0.10} (M = Cd, In and Pb) using the well known Kissinger's relation, Matusita-Sakka theory and the method of Augis-Bennett. The overall mean bond energy of these glassy alloys has been evaluated using theory of Tichy and Ticha. A good correlation has been found between E_c and . This indicates that the overall mean bond energy plays an important role in the thermal crystallization of chalcogenide glasses.
Crystalline Textures On The Al-Ni-Co Quasicrystal Surface, Mehmet Erbudak, Jean-Nicolas Longchamp, Yves Weisskopf
Crystalline Textures On The Al-Ni-Co Quasicrystal Surface, Mehmet Erbudak, Jean-Nicolas Longchamp, Yves Weisskopf
Turkish Journal of Physics
We have generated cubic Al alloys as commensurate single crystals on the tenfold-symmetry surface of the quasicrystalline Al-Ni-Co alloy by ion bombarding its surface. We find that the crystal-quasicrystal interface contains several alignments of mutual high-symmetry directions and planes. In order to explore the structural matching conditions at the crystal-quasicrystal interface, we have grown Al films on the decagonal surface of Al-Ni-Co by vapor deposition. The initial growth mode of Al is commensurate. As the coverage is increased, Al starts to grow in cubic textures breaking into multi-twinned, few-nanometer- large domains. The symmetry of the substrate determines thereby the orientation …
High Conducting Nanowires Obtained From Uniform Titanium Covered Carbon Nanotubes, Sefa Dağ, Engi̇n Durgun, Sali̇m Çiraci
High Conducting Nanowires Obtained From Uniform Titanium Covered Carbon Nanotubes, Sefa Dağ, Engi̇n Durgun, Sali̇m Çiraci
Turkish Journal of Physics
We have shown that Ti atoms can form continuous coating of carbon nanotubes at different amount of coverage. The circular cross section changes to a square-like form, and the semiconducting tube becomes ferromagnetic metal with high quantum ballistic conductance. Metallicity is induced not only by the metal-metal coupling, but also by the band gap closing of SWNT at the corners of the square. The magnetic properties of Ti coated tubes depend strongly on the geometry, amount of Ti coverage and also on the elastic deformation of the tube. While the magnetic moment can be pronounced significantly by the positive axial …
The Magnetic Behaviour Of The Surface And Bulk Components Of Tb(0001)Films, Orhan Zeybek
The Magnetic Behaviour Of The Surface And Bulk Components Of Tb(0001)Films, Orhan Zeybek
Turkish Journal of Physics
The use of circularly polarised light in photoemission from ferromagnetically ordered rare earth's (RE) shows large magnetic circular dichroism in angular dependence (MCDAD) effect. Therefore MCDAD in photoemission from RE's provides new perspectives for surface magnetism studies within the view of the recently postulated sum rules. This allows to probe magnitude and orientation of the sample magnetisation without time-consuming electron-spin analysis. The well-resolved multiplet structures have been obtained in 5p photoemission of Tb using circularly polarised light. This multiplet structure is caused by the interaction between the core level photohole and those partially filled subshell, i.e. as result of the …
Geotectonic Setting And Origin Of The Youngest Kula Volcanics (Western Anatolia), With A New Emplacement Model, Murat Tokçaer, Samuele Agostini, Mehmet Yilmaz Savaşçin
Geotectonic Setting And Origin Of The Youngest Kula Volcanics (Western Anatolia), With A New Emplacement Model, Murat Tokçaer, Samuele Agostini, Mehmet Yilmaz Savaşçin
Turkish Journal of Earth Sciences
The Quaternary Kula volcanics are Na-dominant in character while all the older volcanic rocks of western Anatolia are generally definitive K-dominant rocks. As a unique example in western Anatolia, the existence of a huge amount of plateau basalts at Kula indicates rapid uplift of mantle material, as confirmed by new geochemical data. Based on our field observations, the oldest Kula volcanics are the plateau basalts with more than one main lava flow. At the beginning of volcanic activity (first-period plateau basalts), this plateau was vast. Subsequently, parts of the first-period plateau basalts were uplifted and partly eroded while other parts …
Evolution Of And Factors Controlling Eocene Sedimentation In The Darende-Balaban Basin, Malatya (Eastern Turkey), Kemal Gürbüz, Murat Gül
Evolution Of And Factors Controlling Eocene Sedimentation In The Darende-Balaban Basin, Malatya (Eastern Turkey), Kemal Gürbüz, Murat Gül
Turkish Journal of Earth Sciences
Collision of the Arabian and Anatolian plates affected evolution of basins located along the southern flank of the Anatolian Plate. The Darende-Balaban foreland basin is one such basin a basin filled with Upper Cretaceous and Eocene sediments, accumulated unconformably and transgressively above ophiolitic and carbonate basement rocks. This basin is locally surrounded, to the north and south, by Late JurassicEarly Cretaceous structural highs created by tectonic elements during the collision of Arabia and Anatolia. This paper aims to describe the factors controlling and evolution of the Eocene sedimentation in the Darende-Balaban basin. The basin fill comprises two distinct sequences …
A Property Of Weak Convergence Of Positive Contractions Of Von Neumann Algebras, Farrukh Mukhamedov, Seyi̇t Temi̇r
A Property Of Weak Convergence Of Positive Contractions Of Von Neumann Algebras, Farrukh Mukhamedov, Seyi̇t Temi̇r
Turkish Journal of Mathematics
In the present paper we prove that the mixing property of positive L^1-contraction of finite von Neumann algebras implies the property of complete mixing.
Computation Of Association Probabilities For Single Target Tracking With The Use Of Adaptive Neuro-Fuzzy Inference System, İlke Türkmen, Keri̇m Güney
Computation Of Association Probabilities For Single Target Tracking With The Use Of Adaptive Neuro-Fuzzy Inference System, İlke Türkmen, Keri̇m Güney
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a simple method based on the adaptive neuro-fuzzy inference system (ANFIS) is presented for computing the association probabilities. The computed association probabilities are used to track the single manoeuvring target in the cluttered environment. A hybrid learning algorithm, which combines the least square method and the backpropagation algorithm, is used to identify the parameters of ANFIS. The tracks estimated by using the method proposed in this study are in very good agreement with the true tracks. Better accuracy with respect to the well known nearest neighbour Kalman filter and probabilistic data association algorithms is obtained.
On Generalization Of The Quasi Homogeneous Riesz Potential, Hüseyi̇n Yildirim
On Generalization Of The Quasi Homogeneous Riesz Potential, Hüseyi̇n Yildirim
Turkish Journal of Mathematics
In this paper, a generalization of the quasi homogeneous Riesz Potential has been defined using non-isotropic quasi-distance and its L_p (p \geq 1) continuity study.
Features Of Daily Variation In Cosmic Ray Intensity During High/Low Amplitude Events, Rajesh K. Mishra, Rekha Agarwal Mishra
Features Of Daily Variation In Cosmic Ray Intensity During High/Low Amplitude Events, Rajesh K. Mishra, Rekha Agarwal Mishra
Turkish Journal of Physics
A detailed study has been conducted on the long-term changes in the diurnal, semi-diurnal and tri-diurnal anisotropy of cosmic rays in terms of the high/low amplitude anisotropic wave train events (HAE/LAE) during the period 1981--94 using the neutron monitor data from the Deep River neutron monitoring station. In all, 38 HAE and 28 LAE cases have been studied. An inter-comparison of the first three harmonics during these events has been made so as to understand the basic reason causing the occurrence of these types of events. It has been observed that the phase of diurnal anisotropy shifts towards earlier hours …
Photoconductivity Of Selenium And Sulphur Doped A-Si:H Thin Films, Sanjeev Kumar Sharma, Himanshu Gupta, Rajendra Kumar, Ram Mohan Mehra
Photoconductivity Of Selenium And Sulphur Doped A-Si:H Thin Films, Sanjeev Kumar Sharma, Himanshu Gupta, Rajendra Kumar, Ram Mohan Mehra
Turkish Journal of Physics
This paper presents a study of photoconductivity of S- and Se-doped a-Si:H as a function of composition and temperature. Temperature dependence of photoconductivity of the films was measured under the illumination of white light at 100~mW/cm^2. The room temperature photoconductivity for the same doping concentration of 10^{-4} (to develop H_2Se/SiH_4 and H_2S/SiH_4) is found to be higher in Se-doped -- than S-doped -- a-Si:H film due to a low defect density. From the measurement of intensity dependence of photoconductivity, it is found that the addition of Se and S changes the recombination mechanism from monomolecular, for low-doped films, to bimolecular …
Stratigraphy Of The Volcanic Products Around Nemrut Caldera: Implications For Reconstruction Of The Caldera Formation, Özgür Karaoğlu, Yavuz Özdemi̇r, A. Ümi̇t Tolluoğlu, Mustafa Karabiyikoğlu, Onur Köse, Jean-Luc Froger
Stratigraphy Of The Volcanic Products Around Nemrut Caldera: Implications For Reconstruction Of The Caldera Formation, Özgür Karaoğlu, Yavuz Özdemi̇r, A. Ümi̇t Tolluoğlu, Mustafa Karabiyikoğlu, Onur Köse, Jean-Luc Froger
Turkish Journal of Earth Sciences
The volcanological development of the Nemrut stratovolcano, located near the southwestern tip of Lake Van in eastern Turkey, is subdivided into three stages: pre-caldera, post-caldera and late stages. Two ignimbrite flows have been recognized in the pre-caldera stage. The earlier of the two occurred after basaltic lavas formed along extensional fissures. The latter, which forms the main subject of this paper, was a major flow associated with the development of the Nemrut caldera. The pyroclastic deposits of the Nemrut volcano in the pre-caldera stage are divided into three phases on the basis of palaeosols that separate them. The first phase …
Synthesis And Complex Formation Of Some Novel Vic-Dioxime Derivatives Of Hydrazones, Nursabah Sarikavakli, Gazi̇ İrez
Synthesis And Complex Formation Of Some Novel Vic-Dioxime Derivatives Of Hydrazones, Nursabah Sarikavakli, Gazi̇ İrez
Turkish Journal of Chemistry
Three novel vic-dioxime compounds and their transition metal complexes were synthesized for the first time. These ligands are anti-glyoximehydrazine (GH_2), anti-2-pyridinealdehydeglyoxime hydrazone (PyGH_2) and anti-2-furancarboxaldehydeglyoxime hydrazone (FGH_2). The synthesized anti-glyoximehydrazine was reacted with 2-pyridinealdehyde or 2-furancarboxaldehyde to obtain the PyGH_2 and FGH_2 ligands. Mononuclear complexes of these ligands with a metal-ligand ratio of 1:2 were prepared with Ni(II), Co(II) and Cu(II) ions. The structures of the ligands and complexes were determined by ^1H n.m.r, i.r spectroscopy and elemental analytical techniques.
Magic Gold Nanotubes, R. Tuğrul Senger, Sefa Dağ, Sali̇m Çiraci
Magic Gold Nanotubes, R. Tuğrul Senger, Sefa Dağ, Sali̇m Çiraci
Turkish Journal of Physics
In recent ultra-high-vacuum transmission-electron-microscopy experiments evidence is found for the formation of suspended gold single-wall nanotubes (SWNTs) composed of five helical strands. Similar to carbon nanotubes, the (n,m) notation defines the structure of the gold SWNTs. Experimentally, only the (5,3) tube has been observed to form among several other possible alternatives. Using first-principles calculations we demonstrate that gold atoms can form both freestanding and tip-suspended, chiral, single-wall nanotubes. Although freestanding, infinite (5,5) tube is found to be energetically the most favorable, the experimentally observed (5,3) tube, suspended between two tips, corresponds to a local minimum in the variation of string-tension …
Forward-Backward Diffusion With Continuous Spectrum, Jorge Aarao
Forward-Backward Diffusion With Continuous Spectrum, Jorge Aarao
Turkish Journal of Mathematics
We prove existence and uniqueness of solutions for a class of forward-backward diffusion equations via a representative example, where the second-order part has continuous spectrum, and the initial and boundary data are suitably chosen.
On Marcinkiewicz Integrals Along Flat Surfaces, Ahmad Al-Salman
On Marcinkiewicz Integrals Along Flat Surfaces, Ahmad Al-Salman
Turkish Journal of Mathematics
In this paper, we study Marcinkiewicz integral operators with rough kernels supported by surfaces given by flat curves. Under convexity assumptions on our surfaces, we establish an L^p boundedness result of such operators. Moreover, we obtain the L^p boundedness of the corresponding Marcinkiewicz integral operators that are related to area integral and Littlewood-Paley g_{\lambda}^* functions.
Quotient F-Modules, Ayşe Uyar
Quotient F-Modules, Ayşe Uyar
Turkish Journal of Mathematics
Let L be an f-module over f-algebra A. Then L^{\sim} is a cf-module over the f-algebra (A^{\sim})^{\sim}_n. Quotient f-modules are studied and subsequently a connection between Z(L^{\sim}) and [A^{\sim})^{\sim}_n]_{\hat{e}} is investigated.
Submanifolds Of Riemannian Product Manifolds, Mehmet Atçeken
Submanifolds Of Riemannian Product Manifolds, Mehmet Atçeken
Turkish Journal of Mathematics
In this paper, we study the geometry of the semi-invariant submanifolds of a Riemannian product manifold. Fundamental properties of these type submanifolds such as the integrability of the distributions D, D^{\bot} and mixed-geodesic property are studied. Finally, necessary and sufficient conditions are given on a semi-invariant submanifold of Riemannian product manifold to be D-geodesic and D^{\bot}-geodesic.
Anodic Stripping Voltammetric Behavior Of Mercury In Chloride Medium And Its Determination At A Gold Film Electrode, Füsun Okçu, F. Ni̇l Ertaş, H. İsmet Gökçel, Hüseyi̇n Tural
Anodic Stripping Voltammetric Behavior Of Mercury In Chloride Medium And Its Determination At A Gold Film Electrode, Füsun Okçu, F. Ni̇l Ertaş, H. İsmet Gökçel, Hüseyi̇n Tural
Turkish Journal of Chemistry
The electrochemical behavior of aqueous Hg(II) ions at a gold film electrode is described. The effects of supporting electrolyte and halide ions on the anodic stripping voltammetric behavior of Hg(II) ions was illustrated to prepare a basis for the analysis in real samples with high saline content. The concentration ratio of metallic mercury to halide ions at the electrode surface determines the resulting peak characteristics. The peak potentials in particular shift in a more negative direction as the halide concentration increases. A comparative study with Cu(II) ions revealed that a different mechanism is involved in their reoxidation steps. Mercuric ions …
Electrical Properites Of Superconducting Cross - (Nano) Whiskers Junction, Serdar Altin, Eyüphan Yakinci, Yakup Balci, M. Ali̇ Aksan
Electrical Properites Of Superconducting Cross - (Nano) Whiskers Junction, Serdar Altin, Eyüphan Yakinci, Yakup Balci, M. Ali̇ Aksan
Turkish Journal of Physics
Bi-2212 superconducting single crystal (nano) whiskers have been fabricated by annealing a melt-quenched (glass) Bi_3Sr_2Ca_2Cu_3O_x precursor. A couple of (nano) Whiskers obtained were placed crosswise on a YSZ single crystal substrate and then heat treated at 830 C for 25 minute to form nano-scale junction. The T_c of each nano-whisker was found to be 85 K and the critical current density, J_c, of the whiskers was calculated to be 1177 Acm^{-2} at zero field. The I-V characteristics of the nano-junction at 30 K were found to show a multiple-branch structure, which is the main behavior of the Josephson junction.
Stratigraphy And Geochronology Of The Early Miocene Volcanic Units In The Bigadiç Borate Basin, Western Turkey, Fuat Erkül, Cahi̇t Helvaci, Hasan Sözbi̇li̇r
Stratigraphy And Geochronology Of The Early Miocene Volcanic Units In The Bigadiç Borate Basin, Western Turkey, Fuat Erkül, Cahi̇t Helvaci, Hasan Sözbi̇li̇r
Turkish Journal of Earth Sciences
Western Turkey has undergone an intense deformation which has given rise to two types of basins since the Late Oligocene: NE-trending and E-W-trending basins situated on the basement rocks of the Menderes Massif, the Sakarya Zone, the Lycian nappes and the Bornova Flysch Zone. One of the NE-trending basins, the Bigadiç borate basin, is located in the Bornova Flysch Zone - a 50-90-km-wide zone between the Sakarya Zone and the Menderes Massif. Lower Miocene successions are dominated by lacustrine, fluvial, evaporitic sedimentary rocks and numerous NE-trending volcanic centres which produced considerable amounts of lava and volcaniclastic detritus in the Bigadiç …
Simplex Codes Over The Ring \Sum_{N=0}^Su^N F_2, Mohammed M. Al-Ashker
Simplex Codes Over The Ring \Sum_{N=0}^Su^N F_2, Mohammed M. Al-Ashker
Turkish Journal of Mathematics
In this paper, we introduce simplex linear codes over the ring \sum_{n=0}^{n=s}u^n F_2 of types \alpha and \beta, where u^{s+1}=0. And we determine their properties. These codes are an extension and generalization of simplex codes over the ring Z_{2^s}.
Maximal Oscillatory Singular Integrals With Kernels In L Log L(S^{N-1}), Ahmad Al-Salman
Maximal Oscillatory Singular Integrals With Kernels In L Log L(S^{N-1}), Ahmad Al-Salman
Turkish Journal of Mathematics
In this paper, we study the L^p mapping properties of a certain class of maximal oscillatory singular integral operators. We establish the L^p boundedness of our operators provided that their kernels belong to the natural space L log ^+L(S^{n-1}). Our result substantially improves a previously known result. Moreover, the approach developed in this paper can be applied to handle more general maximal oscillatory singular integral operators.
On Rough Singular Integrals Along Surfaces On Product Domains, Ahmad Al-Salman, Ali A. Al-Jarrah
On Rough Singular Integrals Along Surfaces On Product Domains, Ahmad Al-Salman, Ali A. Al-Jarrah
Turkish Journal of Mathematics
In this paper, we study a class of singular integrals along surfaces on product domains with kernels in L(log L)^2(S^{n-1} \times S^{m-1}). We formulate a general theorem concerning the L^p boundedness of these operators. As a consequence of this theorem we establish L^p estimates of several classes of operators whose L^p boundedness in the one parameter setting is known. The condition L(log L)^2(B^{n-1} \times S^{m-1}) is known to be an optimal size condition
On Linear The Homeomorphism Between Function Spaces C_P(X) And C_{P,A}(X) \Times C_P (A), Sabri̇ Bi̇rli̇k
On Linear The Homeomorphism Between Function Spaces C_P(X) And C_{P,A}(X) \Times C_P (A), Sabri̇ Bi̇rli̇k
Turkish Journal of Mathematics
In this paper, we investigate a linear homeomorphism between function spaces C_p(X) and C_{p,A}(X) \times C_p(A) , where X is a normal space and A is a neighborhood retraction of X.
On Space Of Parabolic Potentials Associated With The Singular Heat Operator, Si̇nem Sezer, İlham A. Ali̇ev
On Space Of Parabolic Potentials Associated With The Singular Heat Operator, Si̇nem Sezer, İlham A. Ali̇ev
Turkish Journal of Mathematics
Anisotropic spaces L_{p,\gamma}^{\alpha} of parabolic Bessel potentials, associated with the singular heat operator I-\Delta_{\gamma}+ \frac{\partial}{\partial t}, where \Delta_{\gamma} = \sum\limits_{k=1}^n \frac{\partial ^{2}}{\partial x_{k}^{2}} + \frac{2\gamma }{x_n}. \frac{\partial}{\partial x_n}, are introduced, and making use of special wavelet-type transform, a characterization of these spaces is obtained.
Design, Simulation And Tests Of A Low-Cost Microstrip Patch Antenna Arrays For The Wireless Communication, Gonca Çakir, Levent Sevgi̇
Design, Simulation And Tests Of A Low-Cost Microstrip Patch Antenna Arrays For The Wireless Communication, Gonca Çakir, Levent Sevgi̇
Turkish Journal of Electrical Engineering and Computer Sciences
Typical low-cost, low-weight microstrip base station antenna arrays with beam-scanning capabilities are taken into account. In downtowns of large cities like New York, Chicago, and in historical cities like Istanbul, where high buildings are separated by narrow but densely occupied streets, antenna arrays with approximately 20°-35° beam-widths are required to complete the cellular communication coverage. To meet this requirement, new antenna arrays are designed with 35° beam-widths and 60° electronic scanning capabilities. Their characteristics are investigated both numerically and experimentally. An FDTD-based antenna simulation package (M-PATCH) is prepared, tested on canonical structures and against the literature first, for verification and …
A New Cmos Differential Otra Design For The Low Voltage Power Supplies In The Sub-Micron Technologies, Alper Duruk, Hakan Kuntman
A New Cmos Differential Otra Design For The Low Voltage Power Supplies In The Sub-Micron Technologies, Alper Duruk, Hakan Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a new CMOS differential OTRA topology is proposed. This topology can operate with a very low voltage power supply as \pm 0.6V. In this design, CMOS 0.13 \mu m STMicroelectronics technology transistor models are used for the simulations. The designed CMOS OTRA has a transresistance gain (Rm) of 7478 V/I with a 28.1 MHz bandwidth (-3 dB) and a transresistance unity-gain bandwidth of 2 GHz. To demonstrate the performance of the OTRA, designed low pass, high pass and band pass filters employing a single CMOS differential OTRA and passive elements are tested with SPICE simulation program to …
A Robustness Analysis Procedure For Realistic Missiles, Reşat Özgür Doruk, Erol Kocaoğlan
A Robustness Analysis Procedure For Realistic Missiles, Reşat Özgür Doruk, Erol Kocaoğlan
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a robustness analysis procedure for short range realistic missile autopilots. The sensitivity of the autopilots to the aerodynamic parameter uncertainties is investigated through the structured singular value theory where the results are verified through nonlinear simulations. Different types of perturbations are implemented in order to measure the complete performance of the missile.
A Model For User Profiling Systems With Interacting Agents, Sanem Sariel, Tevfi̇k Akgün
A Model For User Profiling Systems With Interacting Agents, Sanem Sariel, Tevfi̇k Akgün
Turkish Journal of Electrical Engineering and Computer Sciences
Service systems according to users' personal demands and preferences are on their way to provide required services in many application domains. Emulation of interactive model of human societies produces valuable outcomes for such systems. In this work, a system model with interactive agents for multi user service systems is proposed. A novel social interactive agent model using different interaction forms is also included in this proposal. In this model, agents decide how to serve to their users by considering their users' profiles and information from other agents. User clusters are formed by clustering techniques. The Q-learning algorithm is used for …