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Algebraic Implementation Of Gauss' Law, Andrzej Herdegen
Algebraic Implementation Of Gauss' Law, Andrzej Herdegen
Turkish Journal of Physics
A C^*-algebraic model may be constructed for the description of asymptotic fields in quantum electrodynamics. In this model charged fields carry the asymptotic Coulomb field of associated charged particles.
Differentiating Type Of Muscle Movement Via Ar Modeling And Neural Network Classification, Beki̇r Karlik
Differentiating Type Of Muscle Movement Via Ar Modeling And Neural Network Classification, Beki̇r Karlik
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this study is to classify electromyogram (EMG) signals for controlling multifunction proshetic devices. An artificial neural network (ANN) implementation was used for this purpose. Autoregressive (AR) parameters of $a_1, a_2, a_3, a_4$ and their signal power obtained from different arm muscle motions were applied to the input of ANN, which is a multilayer perceptron. At the output layer, for 5000 iterations, six movements were distinguished at a high accuracy of 97.6%.
Neural Classifiers For Learning Higher-Order Correlations, Marifi Güler
Neural Classifiers For Learning Higher-Order Correlations, Marifi Güler
Turkish Journal of Physics
Studies by various authors suggest that higher-order networks can be more powerful and are biologically more plausible with respect to the more traditional multilayer networks. These architectures make explicit use of nonlinear interactions between input variables in the form of higher-order units or product units. If it is known a priori that the problem to be implemented possesses a given set of invariances like in the translation, rotation, and scale invariant pattern recognition problems, those invariances can be encoded, thus eliminating all higher-order terms which are incompatible with the invariances. In general, however, it is a serious set-back that the …
Ordering Due To Disorder In Frustrated Quantum Magnetic Systems, Taner Yildirim
Ordering Due To Disorder In Frustrated Quantum Magnetic Systems, Taner Yildirim
Turkish Journal of Physics
The phenomenon of order by disorder in frustrated magnetic systems is reviewed. Disorder (thermal or quantum fluctuations) may sometimes give rise to long range ordering in systems with frustration, where one must often consider the selection among classically degenerate ground states which are not equivalent by any symmetry. The lowest order effects of quantum fluctuations in such frustrated systems usually resolves the continues degeneracy of the ground state manifold into discrete Ising--type degeneracy. A unique ground state selection out of this Ising degenerate manifold then occurs due to higher order effects of quantum fluctuations. For systems such as face-centered cubic …
Diverging Strains Near Threshold: Breakdown Of The Elastic Description Of A Charge Density Wave Model, Muhittin Mungan, Susan N. Coppersmith, Valeri M. Vinokur
Diverging Strains Near Threshold: Breakdown Of The Elastic Description Of A Charge Density Wave Model, Muhittin Mungan, Susan N. Coppersmith, Valeri M. Vinokur
Turkish Journal of Physics
We analyze the strains near threshold in 1-d charge density wave models at zero temperature and strong pinning. We show that in these models local strains diverge near the depinning threshold and characterize the scaling behavior of the phenomenon. This helps quantify when the underlying elastic description breaks down and plastic effects have to be included.
Photon Counting In Astrophotometry. Fundamentals And Some Advices For Beginners, Romualdas Kalytis
Photon Counting In Astrophotometry. Fundamentals And Some Advices For Beginners, Romualdas Kalytis
Turkish Journal of Physics
The beginners in astrophotometry are reminded of fundamentals of photon counting. Several advices for new users of electrophotometric technics are given.
Kinematics Of Rs Cvn And W Uma Binaries In The Hipparcos Catalogue, Zeki̇ Aslan, Tuncay Özdemi̇r, Cahi̇t Yeşi̇lyaprak, Ahmet İskender
Kinematics Of Rs Cvn And W Uma Binaries In The Hipparcos Catalogue, Zeki̇ Aslan, Tuncay Özdemi̇r, Cahi̇t Yeşi̇lyaprak, Ahmet İskender
Turkish Journal of Physics
Space motions of RS CVn and W UMa binaries have been calculated using parallaxes and proper motions from Hipparcos catalogue and radial velocities from the literature. We have calculating the mean motions and velocity dispersions. We have excluded those binaries with relative parallax errors \geq 0.5. The comparison of the asymmetric drift, velocity ellipsoids and vertex deviation with those of main sequence stars given by Dehnen and Binney indicates that both RS CVn and W UMa binaries have kinematics similar to main sequence stars slightly bluer than the Parenago's discontinuity and B-V \simeq 0.62. Implication of this has been discussed.
Heat Pulse Studies Of The Emission And Absorption Of Acoustic Phonons In Gaas Quantum Wells And Wires, A. J. Kent
Heat Pulse Studies Of The Emission And Absorption Of Acoustic Phonons In Gaas Quantum Wells And Wires, A. J. Kent
Turkish Journal of Physics
This paper reviews some recent experiments in which heat pulse techniques have been used to study the interaction of acoustic phonons with electrons in semiconductor quantum wells and wires. Heat pulse experiments provide temporal and spatial resolution of the phonons that are emitted or absorbed by the electrons and so give more detailed information about the electron-phonon interaction than can be obtained by other methods (e.g. transport measurements). Phonon experiments demonstrate clearly the effect of the electron confinement on the carrier-phonon interaction and the overall energy loss rate due to acoustic phonon emission. A qualitative explanation of the results is …
Modelling Of Devices For Optoelectronic Applications: The Quantum Confined Stark Effect And Self-Electrooptic Effect Devices, Eckehard Scholl
Modelling Of Devices For Optoelectronic Applications: The Quantum Confined Stark Effect And Self-Electrooptic Effect Devices, Eckehard Scholl
Turkish Journal of Physics
Electro-optical effects, such as the Franz-Keldysh effect in bulk materials or the quantum confined Stark effect in quantum well structures, lead to strong optoelectronic nonlinearities which form the basis for optical modulators and optically bistable devices. They result from a modification of the optical absorption properties by an applied electric field and are particularly pronounced in the case of low dimensional semiconductors. We review theoretical modelling and computer simulations of such optoelectronic devices in particular for ZnSe based quantum well structures, where excitonic features dominate even at room temperature. The field dependent absorption spectra are calculated by a many-body theory …
Stability Of Quasi-Two-Dimensional Bipolarons, R. Tuğrul Senger, Ati̇lla Erçelebi̇
Stability Of Quasi-Two-Dimensional Bipolarons, R. Tuğrul Senger, Ati̇lla Erçelebi̇
Turkish Journal of Physics
The stability criteria of quasi-two-dimensional dimensional bipolarons have been studied within the framework of strong coupling and path-integral theories. It is shown that the critical values of the electron-phonon coupling constant (\alpha), and the ratio of dielectric constants (\eta = \epsilon_{\infty}/\epsilon_{0}) exhibit some non-trivial features as the effective dimensionality is tuned from three to two.
Band-Gap Renormalization In Quantum Wires, K. Güven, C. R. Bennett, B. Tanatar
Band-Gap Renormalization In Quantum Wires, K. Güven, C. R. Bennett, B. Tanatar
Turkish Journal of Physics
Improved techniques in semiconductor fabrication increased the interest in quantum wire structures, because of their opto-electronic device application possibilities. Many-body interactions among the electrons and holes in the wire lead to the band-gap renormalization (BGR), which in turn affect the optical properties of the system. We study the BGR within the random-phase approximation incorporating the dynamical effects, and investigate the density dependence.
Light Emission From Travelling Space Charge Domains, M. Hostut, N. Balkan
Light Emission From Travelling Space Charge Domains, M. Hostut, N. Balkan
Turkish Journal of Physics
We report light emission from n-doped GaAs epilayers associated with impact ionization when the device is biased in the negative difference resistance (NDR) regime (F > 3.5 kV cm^{-1}). Spectral distribution of the emitted light (electroluminescence) has been measured to identify the energy distribution of the recombining electron-hole pairs. Electron temperatures, calculated from the high energy tail of the electroluminescence spectra, show that the light emission is due to the recombination of the impact ionized holes with the background, channel, and the travelling space charge electrons. The range of the electron temperatures obtained indicate that the contribution to the light emission …
The Orbit Center Dependence Of The Energy Levels In A Multiple Quantum Wells Under External Tilted Magnetic And Electric Fields, R. Amca, Y. Ergün, H. Sari, S. Elagöz, İ. Sökmen
The Orbit Center Dependence Of The Energy Levels In A Multiple Quantum Wells Under External Tilted Magnetic And Electric Fields, R. Amca, Y. Ergün, H. Sari, S. Elagöz, İ. Sökmen
Turkish Journal of Physics
An analytical solution to the Schrödinger equation for a multiple quantum well system subjected to an externally applied electric field the growth direction and an externally applied tilted magnetic field are obtained and the results are discussed. The energy dependence energy spectrum of the system as a function of the external electric field and the orbit center is also discussed.
Feasibility Of Fabrication Of Heteroepitaxial Ge_X Si_{1-X}/Si(111) Structure By Pulsed Nd: Yag Laser, R. N. Al-Rawi, R. A. Ismail, R. N. Mousis
Feasibility Of Fabrication Of Heteroepitaxial Ge_X Si_{1-X}/Si(111) Structure By Pulsed Nd: Yag Laser, R. N. Al-Rawi, R. A. Ismail, R. N. Mousis
Turkish Journal of Physics
Heteroepitaxial Ge_x Si_{1-x} alloy layers have been formed by 10 ms and 300 \mu s laser pulse induced mixing of pure germanium films and Si(111) substrates where Ge films of thickness (500-1250) Å are thermally evaporated onto Si(111) under vacuum pressure \sim 10^{-5} Torr. The near surface of the sample then undergoes rapid melting and regrowth processes during each pulse from a free running Nd; YAG laser. The alloy layers are (4.6-6.5) \mum thick and have a Ge fraction of x = 6-8.2%.
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.
Investigation On Changes In Physical And Chemical Properties Of Palm Kernel Oil During Hydrogenation, İhsan Karabulut, Muammer Kayahan
Investigation On Changes In Physical And Chemical Properties Of Palm Kernel Oil During Hydrogenation, İhsan Karabulut, Muammer Kayahan
Turkish Journal of Agriculture and Forestry
Palm kernel oil was hydrogenated discontinuously for a period of 100 min at 165°C and 2,5 atm in the presence of nickel catalyst (%0,18). The changes in iodine number, fatty acid composition, trans fatty acid content and solid fat content during the hydrogenation were investigated for samples taken at 10 min intervals. According to the findings, while iodine number was gradually decreased during the reaction, trans fatty acid content increased significantly. Reaction conditions had increased effect on stearic acid formation from monoens. Trans fatty acid and total saturated fatty acid amounts increased proportionally with increase in SFC values.
Effect Of Subsequent Simulated Rainfalls On Runoff And Erosion, Günay Erpul, Mustafa R. Çanga
Effect Of Subsequent Simulated Rainfalls On Runoff And Erosion, Günay Erpul, Mustafa R. Çanga
Turkish Journal of Agriculture and Forestry
Hydraulic properties of soils and soil erodibility are expected to vary after rainfall because of the impact energy of raindrops. Resistance both to rainfall detachment and to runoff detachment might differ after rainfall, and temporal changes in soil erodibility take place. The main objective of this study was to evaluate the effects of subsequent rainfalls (namely the 2nd rainfall) on runoff and erosion, especially sheet and splash erosion. Forty rainfall events in laboratory condition were conducted on Kule clay loam and Musaagili silt loam. Two consecutive rainfalls at an intensity of 60 mm h -1 were applied to soil trays …
The Relationships Between Penetration Resistance And Certain Soil Properties, Cevdet Şeker
The Relationships Between Penetration Resistance And Certain Soil Properties, Cevdet Şeker
Turkish Journal of Agriculture and Forestry
The purpose of this study was to determine the relationships between penetration resistance and certain soil properties, and to develop regression equations based on these relationships for predicting penetration resistance. Field studies were conducted on four different Entisol soils in plains in the Konya regions. Below 0.2 \mum, pore-size distribution was found to be positively relatd to soil penetration resistanca and bulk density. Above 50 \mum, pro-size distribution was found to be negatively related to soil penetration resistance and total porosity.
The Effects Of Origin And Regional Differences On The Density Of Douglas Fir [Pseudotsuga Menziesii (Mirb.) Franco] Wood, Nurgül Ay, Yalçin Örs
The Effects Of Origin And Regional Differences On The Density Of Douglas Fir [Pseudotsuga Menziesii (Mirb.) Franco] Wood, Nurgül Ay, Yalçin Örs
Turkish Journal of Agriculture and Forestry
In this study, the effects of origin and regional differences on the density of Douglas Fir [Pseudotsuga menziesii (Mirb.) Franco] wood were investigated. A total of 18 trees of 23 different ages obtained from the Maçka and Tonya regions in two origins were used. Density samples 2x2x3 cm in size were prepared accordance with the standards were used for experiments. The effects of origin and regional differences on density were statistically determined. The results showed that the effects of origin on density in oven-dried and air-dried wood were significant, but those of region were not. Density values for air-dried and …
The Effects Of Differences In Origin And Region On Compression Strength Parallel To The Grain Of Douglas Fir [Pseudotsuga Menziesii (Mirb.) Franco] Wood, Yalçin Örs, Nurgül Ay
The Effects Of Differences In Origin And Region On Compression Strength Parallel To The Grain Of Douglas Fir [Pseudotsuga Menziesii (Mirb.) Franco] Wood, Yalçin Örs, Nurgül Ay
Turkish Journal of Agriculture and Forestry
In this study, the effects of differences in origin and region on the compression strength parallel to the grain of Douglas Fir [Pseudotsuga menziesii (Mirb.) Franco] wood were investigated. A total of 18 trees of two origins obtained from the regions of Maçka and Tonya were for comporison. Samples 2x2x3 cm in size in were prepared in accordance with the standards. The effects of differences in origin and region on compression strength parallel to the grain were statistically determined. The results showed that the effects of region were significant, while those of origin were not. The average regional compression strength …
Agricultural Potential Of Steep Rocky Areas On The Eastern Mediterranean Shoreline, Hasan Özcan, Mahmut Çeti̇n
Agricultural Potential Of Steep Rocky Areas On The Eastern Mediterranean Shoreline, Hasan Özcan, Mahmut Çeti̇n
Turkish Journal of Agriculture and Forestry
The aim of this study was to determine the agricultural potential of an area limited by such factors as rockiness, shallow soil profile and steep slope on the eastern Mediterranean shoreline. The soils of the study area were classified according to land use capability and suitability for irrigated agriculture in view of soil survey and laboratory results. After interpretation of the classification results, it was concluded that some physical land improvement measures should be implemented in about 50% of the study area in preparation for intensive farming. Land utilization types (LUT) were determined according to the land characteristics and questionnaire …
Determination Of Land Distribution And Spectral Characteristics Of The Wheat Crop Grown In The West Mediterranean Region By Using Digital Satellite Data, Namik Kemal Sönmez, Mustafa Sari
Determination Of Land Distribution And Spectral Characteristics Of The Wheat Crop Grown In The West Mediterranean Region By Using Digital Satellite Data, Namik Kemal Sönmez, Mustafa Sari
Turkish Journal of Agriculture and Forestry
The aim of this study was to determine the spectral characteristics and distribution of the wheat growing areas in West Mediterranean Region by means of the digital data from the Landsat-5 Thematic Mapper (TM) Satellite. Optimum band combination was found to be 4th, 5th and 7th bands for determination of the wheat growing areas in this region. The TM digital data of the research area was classified by using maximum likelihood method with this band combination. In conclusion, the wheat-grown areas could be defined by with 95.3 % confidence.
Flexion Contractures In A Diabetic Young Man(Rosenbloom Syndrome), Serpi̇l Savaş, Yavuz Bardak, Şevket Ercan Tunç, Meltem Çeti̇n, Selami̇i̇ Akkuş
Flexion Contractures In A Diabetic Young Man(Rosenbloom Syndrome), Serpi̇l Savaş, Yavuz Bardak, Şevket Ercan Tunç, Meltem Çeti̇n, Selami̇i̇ Akkuş
Turkish Journal of Medical Sciences
No abstract provided.