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Articles 9781 - 9810 of 10317
Full-Text Articles in Physical Sciences and Mathematics
On The Experimental Search For Photon Mixing, Vsevolod Popov
On The Experimental Search For Photon Mixing, Vsevolod Popov
Turkish Journal of Physics
The experimental searches for photon mixing in the Okun model [1] are discussed.
Electrical Switching In Potassium-Boro-Vanadate-Iron Glasses, H. R. Panchal, D. K. Kanchan
Electrical Switching In Potassium-Boro-Vanadate-Iron Glasses, H. R. Panchal, D. K. Kanchan
Turkish Journal of Physics
Electrical switching has been observed in 20K_2O : (75-y)V_2O_5 : yB_2O_3 : 5Fe_2O_3 glasses which were prepared by a splat quenching method. To investigate switching phenomenon, glass samples of the same dimension from as quenched material were examined for their I-V characteristics at various ambient temperatures. The exponential decrease of switching voltage is observed with increasing ambient temperature indicating the cause of switching due to Joule's heating. It is also observed that the switching voltage can be controlled by varying the ambient temperature and switching temperature by changing the voltage. The dependence of switching temperature on the amount of V_2O_5 …
Electronic And Lattice Thermal Conductivity Of Bi_{1-X} Sb_X And Ag-Sb-Te Systems, Sabi̇r Ali̇yev, Agami̇rza Movsum-Zadeh, Sadiyar Ragimov, Eldar Zulfigarov
Electronic And Lattice Thermal Conductivity Of Bi_{1-X} Sb_X And Ag-Sb-Te Systems, Sabi̇r Ali̇yev, Agami̇rza Movsum-Zadeh, Sadiyar Ragimov, Eldar Zulfigarov
Turkish Journal of Physics
An investigation of the electronic (\aleph_e) and lattice (\aleph_L) parts of the thermal conductivity for samples of Bi_{1-x} Sb_x (0,02 < X < 0,12) and system of Ag-Sb-Te was carried out in the temperature interval 6-300K. Separation of \aleph_L and \aleph_e has been made by suppressing \aleph_e in magnetic field. The experimental data of \aleph_L and \aleph_e have been compared, respectively, with Gallaway's theory and with a theory which takes into account the inelastic character of scattering. It is observed that the Lorentz number L calculated by using the experimental values of \aleph_e and thermomagnetic coefficients is smaller than its Zommerfeld's value L_0 in high doping Bi_{0.88}Sb_{0.12}. A satisfactory agreement between the theory and the experiment allows to conclude that besides the normal and U-processes in Bi_{1-x}Sb_x the defects of mass also plays a considerable role in scattering. It is observed that \aleph_L of single phase samples Ag_{0.82}Sb_{1.18}Te_{2.18} is smaller than AgSbTe_2 samples. It is shown that this is due to the presence of p-Ag_2 Te in AgSbTe_2. It is established that the high concentration of intrinsic defects plays a considerable role in scattering for Ag-Sb-Te as well.
Relative L X-Ray Fluorescene Cross-Sections In Heavy Elements In The Energy Region Of 16-122 Kev, Oğuz Doğan, Mehmet Ertuğrul, Önder Şi̇mşek, Ümi̇t Turgut, Hasan Erdoğan
Relative L X-Ray Fluorescene Cross-Sections In Heavy Elements In The Energy Region Of 16-122 Kev, Oğuz Doğan, Mehmet Ertuğrul, Önder Şi̇mşek, Ümi̇t Turgut, Hasan Erdoğan
Turkish Journal of Physics
Relative L1, L\alpha, L\beta and L\gamma x-ray fluorescence cross-sections were observed in Ta, W, Re, Au, Hg, T1, Pb, Bi, Th and U of 16.03, 17.78, 22.58, 25.77, 32.89, 38.18, 43.94, 50.21, 59,5 and 122 keV energies. In this study, L X-ray fluorescence cross-sections were measured at 59.5 and 122 keV and measured values of the other energies were taken from tables by Mann et. al. (1). The experimental relative fluorescene cross-sections were computed for the excitation energies 16.03, 17.78, 22.58, 25.77, 32.89, 38.18, 43.94, 50.21, 59.5 and 122 keV, compared with the theoretically calculated values by Scofield(11). The experimental …
Supersymmetric Electroweak Radiative Corrections To E^+ E^- -> W^+W^-, S. Alam
Supersymmetric Electroweak Radiative Corrections To E^+ E^- -> W^+W^-, S. Alam
Turkish Journal of Physics
In this short note we summarize some of the work of our thesis, which is also reported elsewhere in detail. We have examined the one loop quantum corrections to the W pair production in the electron positron annihilation in the context of supersymmetric electroweak theory. We have adopted the On Mass Shell Renormalization scheme of Sakakibara and previously demonstrated the consistency of this scheme. The relevant analytic results are written out. A complete computer program for these corrections has been developed. This program has been checked in several ways to ensure against errors over the life of the calculation where …
Effect Of Illumination Temperature On Thermally Stimulated Current Spectrum Of Tlins_2, Selahatti̇n Özdemi̇r, Rauf Süleymanov, Mahmut Bucurgat, Enver Bulur
Effect Of Illumination Temperature On Thermally Stimulated Current Spectrum Of Tlins_2, Selahatti̇n Özdemi̇r, Rauf Süleymanov, Mahmut Bucurgat, Enver Bulur
Turkish Journal of Physics
The effect of pre-illumination on both thermally stimulated current and photocurrent spectra of TlInS_2 crystal is investigated. The increase in the photosensitivity of the crystal by several orders of magnitude together with the appearance of a new peak in the thermally stimulated current spectrum are observed as a result of the pre-illumination process. The filling of the traps, especially the sensitizing centers, during the pre-illumination is found to be the most favourable physical mechanism to explain the results.
On Symplectic Fillings Of 3-Manifolds, Paola Lisca
On Symplectic Fillings Of 3-Manifolds, Paola Lisca
Turkish Journal of Mathematics
No abstract provided.
The Revovery Of Copper And Cobalt From Oxidized Copper Ore And Converter Slag, Berri̇n Zi̇yadanoğullari, Recep Zi̇yadanoğullari
The Revovery Of Copper And Cobalt From Oxidized Copper Ore And Converter Slag, Berri̇n Zi̇yadanoğullari, Recep Zi̇yadanoğullari
Turkish Journal of Chemistry
The aim of this study was to develop a method for obtaining copper and cobalt from oxidized copper ore and converter slag. In order to convert the copper and cobalt into sulfate compounds the main step was to roast the samples obtained by sulfurization and transfer the samples into solution. First the oxidized copper ore was roasted, followed by the mixture of converter slag and oxidized copper ore. Since the levels of copper and cobalt were low, the sulfurization process was carried out under autoclave conditions. The samples obtained were roasted. The yields of copper and cobalt passed into the …
Electrochemical Preparation And Sensor Properties Of Conducting Polyaniline Films, M. Özden Eki̇nci̇, Ergün Eki̇nci̇, A. Ersi̇n Karagözler
Electrochemical Preparation And Sensor Properties Of Conducting Polyaniline Films, M. Özden Eki̇nci̇, Ergün Eki̇nci̇, A. Ersi̇n Karagözler
Turkish Journal of Chemistry
A polyaniline-glucose oxidase electrode was prepared by the electrochemical polymerization of aniline on a Pt electrode that was already pre-adsorbed by the enzyme (glucose oxidase) at a potential of 1 V vs. Ag/AgCl. Then, the amperometric responses of the enzyme electrode to the electroactive hydrogen peroxide formed by the enzyme-catalyzed reaction of the substrate (glucose) with oxygen were measured at a potential of 0.7 V in PBS solution. The effects of electrochemical polymerization (i.e., concentrations of monomer and electrolyte, film thickness) and amperometric measurement parameters (i.e. pH, temperature) on the amperometric response characteristics to glucose of the resultant enzyme electrode …
An Investigation Of The Formation Mechanism Of Allene Or Alkyne In The 6,7-Benzobicyclo[3.2.1]Octane System By Deuterium Labeling Experiments, Yavuz Taşkesenligil, Ferhan Tümer, Cavi̇t Kazaz, Meti̇n Balci
An Investigation Of The Formation Mechanism Of Allene Or Alkyne In The 6,7-Benzobicyclo[3.2.1]Octane System By Deuterium Labeling Experiments, Yavuz Taşkesenligil, Ferhan Tümer, Cavi̇t Kazaz, Meti̇n Balci
Turkish Journal of Chemistry
In order to reveal the real intermediate in the base-promoted reaction of 1, 3-bromo-4,4-dideuterio-6,7-benzobicyclo[3.2.1]octa-2,6-diene 10 was synthesized and its HBr elimination reaction studied. Reaction of 10 with potassium tert-butoxide yielded butoxyl ether 18 in which proton-deuterium exchange has occured.
Reaction Of Tribromonitromethane With Aldehydes And Ketones In The Presence Of Zn Metal In Aqueous Medium, Ali̇ Shaker Mahasneh
Reaction Of Tribromonitromethane With Aldehydes And Ketones In The Presence Of Zn Metal In Aqueous Medium, Ali̇ Shaker Mahasneh
Turkish Journal of Chemistry
Aldehydes and ketones react with tribromonitromethane in the presence of zinc metal dust, ammonium chloride and water to give dibromonitroalcohols in good yields.
Studies On The Synthesis Of Some Substituted Flavonyl Thiazolidinedione Derivatives-I, Oya Bozdağ, Gülgün Ayhan Kilcigi̇l, Meral Tunçbi̇lek, Rahmi̇ye Ertan
Studies On The Synthesis Of Some Substituted Flavonyl Thiazolidinedione Derivatives-I, Oya Bozdağ, Gülgün Ayhan Kilcigi̇l, Meral Tunçbi̇lek, Rahmi̇ye Ertan
Turkish Journal of Chemistry
Synthesis and some physico-chemical properties of five flavonyl thiazolidinedione derivatives are described. These products were synthesized by Knoevenagel condensation from flavone-6-carboxaldehyde and 3-substituted 2,4-thiazolidinediones.
Complexation Of Benzoate Ligand With The Divalent D^10 Acceptors At Different Temperatures, Betül Başaran, Efrai̇m Avşar
Complexation Of Benzoate Ligand With The Divalent D^10 Acceptors At Different Temperatures, Betül Başaran, Efrai̇m Avşar
Turkish Journal of Chemistry
The complex formation between zinc(II), cadmium(II), mercury(II) and benzoate ions was studied potentiometrically with glass electrode at different temperatures. The measurements have been performed in a perchlorate medium of the unit ionic strength at 25, 30, 35 and 40°C. The stability constants of the complexes were found in the order of increasing softness i.e. Zn(II) < -Cd(II)
Supercritical Co_2 Extraction Of Ethanol, A. Güvenç, Ü. Mehmetoğlu, A. Çalimli
Supercritical Co_2 Extraction Of Ethanol, A. Güvenç, Ü. Mehmetoğlu, A. Çalimli
Turkish Journal of Chemistry
Extraction of ethanol was studied from both synthetic ethanol solution and fermentation broth using supercritical CO_2 in an extraction apparatus in ranges of 313 to 333 K and 80 to 160 atmospheres, for varying extraction times. The experimental system consists mainly of four parts: a CO_2 storage system, a high-pressure liquid pump, an extractor and a product collection unit. Samples were analyzed by gas chromatography. Effects of temperature, pressure, extraction time, initial ethanol concentration and consecutive solvent feeding on extraction yield were investigated. It was found that increasing the initial ethanol concentration and extraction pressure and decreasing the extraction temperature …
The Characterization Of Na_2 Co_3 Activated Kütahya Bentonite, Nuray Yildiz, Yüksel Sarikaya, Ayla Çalimli
The Characterization Of Na_2 Co_3 Activated Kütahya Bentonite, Nuray Yildiz, Yüksel Sarikaya, Ayla Çalimli
Turkish Journal of Chemistry
A calcium bentonite from Kütahya region (Turkey) was activated with Na_2CO_3 at various ratios (1, 2, 2.5, 5, 10, 15g / 100 g bentonite). Due to ion exchange, the original Ca-bentonite was converted to Na-bentonite by Na_2CO_3 when the Na_2CO_3/bentonite ratio was 2.5\% (2.5 g Na_2CO_3/100 22g bentonite, A2.5). Na-bentonite (A2.5) obtained by soda activation was treated with 3 g CaCl_2/ 100 g bentonite and converted to Ca-bentonite again. The products were investigated by chemical analysis, X-ray diffraction and micropore analysis. It was observed that the cation exchange capacity (CEC) did not change until the soda ratio was 2.5\%. After …
Mass Spectral Studies Of Some Triorganotin Derivatives Containing Carboxylates, Moazzam Hussain Bhatti, Sagib Ali, Muhammad Mazhar, Muhammad Danish, Muhammad Azi̇z Chaudhary
Mass Spectral Studies Of Some Triorganotin Derivatives Containing Carboxylates, Moazzam Hussain Bhatti, Sagib Ali, Muhammad Mazhar, Muhammad Danish, Muhammad Azi̇z Chaudhary
Turkish Journal of Chemistry
The mass spectra of 16 triorganotin compounds having the general formula R_3SnL where R= CH_3, C_4H_9, C_6H_5, C_6H_{11} and L=trans-3-(2-furanyl)-2-propenoate, trans-m-methyl cinnamate, 2-(2,3-dimethylphenyl)aminobenzoate and trans-3-(2-thienyl)-2- propenoate, were investigated. The possible fragmentation pattern is discussed in detail.
Effect Of Temperature On The Electrooxidation Of Some Organic Molecules On Pt Doped Conducting Polymer Coated Electrodes, İpek Beceri̇k, Fehmi̇ Fiçicioğlu, Fi̇gen Kadirgan
Effect Of Temperature On The Electrooxidation Of Some Organic Molecules On Pt Doped Conducting Polymer Coated Electrodes, İpek Beceri̇k, Fehmi̇ Fiçicioğlu, Fi̇gen Kadirgan
Turkish Journal of Chemistry
Polymer modified electrodes are of importance as possible electrocatalysts for various electrode reactions, i.e., platinum incorporated into polypyrrole or polyaniline films are known to be good systems for the electrooxidation of various organic molecules. In this study, the effect of temperature on the electrooxidation of D. glucose and methanol on Pt doped films was investigated, apparent activation energies were calculated and the results were evaluated.
Electrochemical Reduction Of Methyl Cinnamate In The Presence Of 1,3-Bis(4-Methyl Phenylsulphonyloxy)Propane, Mustafa Güllü
Electrochemical Reduction Of Methyl Cinnamate In The Presence Of 1,3-Bis(4-Methyl Phenylsulphonyloxy)Propane, Mustafa Güllü
Turkish Journal of Chemistry
Electrochemical reduction of methyl cinnamate in the presence of a dielectrophile, such as 1,3-bis(4-methyl phenylsulphonyloxy)propane gives two major products: trans- (\pm) methyl 2-phenylcyclopentanecarboxylate and trans- (\pm) methyl 2,3-diphenyl-5-oxo-cyclopentanecarboxylate. The ratio of products basically depends on the electrolysis conditions.
Autocatalytic Reduction Of Dichloro 5, 10, 15, 20 Tetraphenylporphinatoplatinum(Iv) By 1-Methylimidazole, F. Ece Bulak
Autocatalytic Reduction Of Dichloro 5, 10, 15, 20 Tetraphenylporphinatoplatinum(Iv) By 1-Methylimidazole, F. Ece Bulak
Turkish Journal of Chemistry
It was observed that in toluene solution, excess 1-methyl-imidazole (Melm) reduces dichloro 5, 10, 15, 20 tetraphenyl-porphinatoplatinum(IV) (PtTPPCl_2) to tetraphenylporphinato-platinum(II) (PtTPP) autocatalytically (Fig. 1). There was no Pt(III) intermediate or 1-methylimidazole radical detected by Electron Resonance Spectroscopy (ESR) at 25°C. The reaction was found to be autocatalyzed by the PtTPP product when the 1-methylimidazole to PtTPPCl_2 concentration ratio is about 10^4 or more. From the data obtained it is reasonable to suppose that aggregation of the PtTPP product with PtTPPCl_2 plays an important role in this reduction process.
Nonextensivity And Quantum Groups, Metin Arik
Nonextensivity And Quantum Groups, Metin Arik
Turkish Journal of Physics
Classical set theory is nonextensive since the mathematical definition of a set excludes the possibility that more than one copy of the same element can be in a set. We show that the description of random sets in terms of an algebra of creation operators and their hermitean conjugates yields an interpretation of the unitary quantum group SU_q(d) as the symmetry associated with the construction of d random sets from a given source set of M=(1-q)^{-1} elements.
Statistical Physics, Neural Networks, Brain Studies, Gerard Toulouse
Statistical Physics, Neural Networks, Brain Studies, Gerard Toulouse
Turkish Journal of Physics
An overview of some aspects of a vast domain, located at the crossroads of physics, biology and computer science is presented: 1) During the last fifteen years, physicists advancing along various pathways have come into contact with biology (computational neurosciences) and engineering (formal neural nets). 2) This move may actually be viewed as one component in a larger picture. A prominent trend of recent years, observable over many countries, has been the establishment of interdisciplinary centers devoted to the study of: cognitive sciences; natural and artificial intelligence; brain, mind and behaviour; perception and action; learning and memory; robotics; man-machine communication, …
Weak Localization In Disordered Two-Dimensional Crystals With Half-Filled Band, E.P. Nakhmedov, T. Kaya
Weak Localization In Disordered Two-Dimensional Crystals With Half-Filled Band, E.P. Nakhmedov, T. Kaya
Turkish Journal of Physics
Effect of subtitutional impurities on electron localization in two dimensional (2D) lattice near the middle of the band is studied. Calculation of density of the electronic states, \rho (\varepsilon ), increases logaritmically in the middle of the band. This singularity in the density of states of noninteracting electron gas on lattice gives rise to anomalous dependencies of thermodynamic quantities on the temperature. The quantum correction to the conductivity of a nonintreracting electron gas due to Umklapp electron--impurity scattering is calculated. This correction to the conductivity is shown to compete with that from the localization corrrection for a Normal scattering process. …
Angular Momentum Evolution In Close Late-Type Binaries, Carla Maceroni
Angular Momentum Evolution In Close Late-Type Binaries, Carla Maceroni
Turkish Journal of Physics
Accurate monitoring of the orbital period of late-type close binaries can provide important information on their secular evolution and on the structural changes of their components on very short timescales (i.e. decades). The orbital period turns out to be a powerful tool of investigation: it can be measured to great accuracy even with simple equipments and its change produces an easily detectable cumulative effect over time. This paper focuses on two physical mechanisms that cause orbital periods changes in late type binaries with negligible mass loss from the system: the dynamical evolution due to magnetic braking in tidally locked systems, …
The Experimental Studies On Zr Photoelectron Spectra, I. Buribayev, N. A. Nurmatov, N. Talipov
The Experimental Studies On Zr Photoelectron Spectra, I. Buribayev, N. A. Nurmatov, N. Talipov
Turkish Journal of Physics
Photoelectron spectra (PES) taken from crystalline Zr at 8.4 eV and 10 eV have been studied by a high resolution photoelectron analyzer, with \Delta E = 0.1 eV, and the results were compared to the results calculated for electron density of states in the valence band. Photoelectron work function (WF) measured from the atomically clean Zr surface by Fowler isothermal curves was found to be 3.95 eV \pm 0.02 eV. It was shown that a small dose of residual gas, namely CO, absorbed on the Zr surface, resulted in a decrease of the WF by 0.15-0.25 eV as well as …
Electrons And Phonons In Gan Semiconductor Quantum Well Devices, M. Babiker, N. A. Zakhleniuk, C. R. Bennett, V. N. Stavrou, B. K. Ridley
Electrons And Phonons In Gan Semiconductor Quantum Well Devices, M. Babiker, N. A. Zakhleniuk, C. R. Bennett, V. N. Stavrou, B. K. Ridley
Turkish Journal of Physics
Electrons and polar optical phonons and their interactions are considered in the context of semiconductor quantum well devices, with particular reference to real quantum well laser structures. Distinction is made between wide-barrier and narrow-barrier structures and we explore the implications of these regimes for the description of the electron capture process. Special emphasis is made on the significant effects arising from the large effective mass ratio in AlN/GaN structures.
Characterization Of Inas/Gaas Qd Structures By Hrem And Pl Spectroscopy, Y. Ati̇ci̇, D. Cherns, A. Polimeni, M. Henini, L. Eaves
Characterization Of Inas/Gaas Qd Structures By Hrem And Pl Spectroscopy, Y. Ati̇ci̇, D. Cherns, A. Polimeni, M. Henini, L. Eaves
Turkish Journal of Physics
No abstract provided.
Improvement In Electroabsorption And The Effect Of The Electric Field In The Tuneable Wavelength Converter, Hüseyi̇n Sari, Esi̇n Kasapoğlu, Yüksel Ergün, İsmai̇l Sökmen
Improvement In Electroabsorption And The Effect Of The Electric Field In The Tuneable Wavelength Converter, Hüseyi̇n Sari, Esi̇n Kasapoğlu, Yüksel Ergün, İsmai̇l Sökmen
Turkish Journal of Physics
The numerical results of the study of a novel wavelength converter which can be tuned with the application of an external field are presented. For this device, exciton binding energies, radiuses and the absorption coefficient are numerically analysed as a function of electric field. We showed that the interband transition energy and the overlap function between electron and hole changes abruptly when an electric field is applied. This phenomenon can be used the increase the change in the absorption coefficient and reduce the on-state transmission loss in electroabsorption modulators.
Electromagnetic Waves In Disordered Dielectric Media: Coupled-Dipole Model, Arkadiusz Orlowski, Marian Rusek
Electromagnetic Waves In Disordered Dielectric Media: Coupled-Dipole Model, Arkadiusz Orlowski, Marian Rusek
Turkish Journal of Physics
An effective approach to multiple scattering of electromagnetic waves by disordered dielectric media is developed. A self-consistent energy-conserving coupled-dipole model is used. Applications to the Anderson localization of electromagnetic waves are presented. A complete set of Maxwell's equations is used to describe the propagation of waves and the vector character of the electromagnetic field is fully taken into account.
Electrodynamics With Toroid Polarization, V. M. Dubovik, B. H. Saha
Electrodynamics With Toroid Polarization, V. M. Dubovik, B. H. Saha
Turkish Journal of Physics
A modified system of equations of electrodynamics of continuous media has been obtained. Beside the Lagrangian system an alternative gauge-like formalism has been developed to introduce the toroid moment contributions in the obtained equations. The two potential formalism that was worked out by us earlier has been developed further where along with the two vector potentials we introduce two scalar potentials thus taking into account all four basic equations of electromagnetism.
Low-Magnetic Field Microwave Absorption In Superconductors And Conducting Polymers, I. L. Khairullin, P. K. Khabibullaev, V. Yu. Sokolov, A. A. Zakhidov
Low-Magnetic Field Microwave Absorption In Superconductors And Conducting Polymers, I. L. Khairullin, P. K. Khabibullaev, V. Yu. Sokolov, A. A. Zakhidov
Turkish Journal of Physics
Low-magnetic field microwave absorption (MA) in superconductors and conducting polymers is analysed in a low-field signal (LFS) version of the MA detecting method. The temperature dependences, hysteretic benavior and other properties of a LFS are compared in superconducting versus non-superonducting systems. Spin selective hopping processes between polarons and bipolarons is proposed to be one of the possible mechanisms of a LFS in non-degenarate conducting polymers.