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Ac Conductivity And Dielectric Study Of Chalcogenide Glasses Of Se-Te-Ge System, Fathy Salman
Ac Conductivity And Dielectric Study Of Chalcogenide Glasses Of Se-Te-Ge System, Fathy Salman
Turkish Journal of Physics
The ac conductivity and dielectric properties of glassy system Se_{x}Te_{79 - x}Ge_{21}, with x = 11, 14, 17 at.%, has been studied at temperatures 300 to 450 K and over a wide range of frequencies (50 Hz to 500 kHz). Experimental results indicate that the ac conductivity and the dielectric constants depend on temperature, frequency and Se content. The conductivity as a function of frequency exhibited two components: dc conductivity \sigma _{dc}, and ac conductivity \sigma _{ac}, where \sigma _{ac} \sim \omega ^{s}. The mechanism of ac conductivity can be reasonably interpreted in terms of the correlated barrier hopping model …
Design And Preparation Of Antireflection And Reflection Optical Coatings, Özlem Duyar, H. Zafer Durusoy
Design And Preparation Of Antireflection And Reflection Optical Coatings, Özlem Duyar, H. Zafer Durusoy
Turkish Journal of Physics
In this study, reflective and antireflective coatings were designed and simulated. Optical transmission and reflection values were deduced with a matrix formulation via a personal computer. It was found that the number of layers affects the optical performance. The width of the high-reflectance region in the reflectance curves decreases, while its height increases with the increasing number of layers for the reflective coating design. The antireflection coatings transmit about 99.89% in a broad high-pass band at the central wavelength of \lambda_{0} = 450 nm. In addition, simulated Fabry-Perot filters result in a single sharp transmittance peak at the desired central …
An Implicit Surface Modeling Technique Based On A Modular Neural Network Architecture, Manuel Carcenac
An Implicit Surface Modeling Technique Based On A Modular Neural Network Architecture, Manuel Carcenac
Turkish Journal of Electrical Engineering and Computer Sciences
Independently from artificial intelligence applications, an artificial neural network can be viewed as a powerful tool for function reconstruction. Previous papers used this property to model an implicit surface out of some control points by reconstructing its underlying scalar field. Such an approach requests the neural network to memorize the control points, which has turned problematic for complex surfaces. In our paper, we show that this problem can be efficiently tackled by adapting the architecture of the neural network to the features compounding the surface: by learning first these features independently and then blending them gradually together, our modular architecture …
Real-Time Classification Algorithm For Recognition Of Machine Operating Modes By Use Of Self-Organizing Maps, Gancho Vachkov, Yuhiko Kiyota, Koji Komatsu, Satoshi Fujii
Real-Time Classification Algorithm For Recognition Of Machine Operating Modes By Use Of Self-Organizing Maps, Gancho Vachkov, Yuhiko Kiyota, Koji Komatsu, Satoshi Fujii
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper a new algorithm for classification and real-time recognition of different a-priorily assumed operating modes for construction machines is proposed. This algorithm utilizes the effectiveness of the Self-Organizing Maps (SOM) for creating the so called Separation Models, that are able to distinguish each operating mode separately. After training, these models are used in a real-time procedure, which calculates at each sampling time the minimal Euclidean distances from the current data point to a certain node of each SOM. Then the separation model (represented by a respective SOM) that has the least minimal distance to this data point defines …
Cover And Contents
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Nutritive Value Of Pastures In Kars District I. Botanical And Nutrient Composition At Different Stages Of Maturity, İsmai̇l Kaya, Ahmet Öncüer, Yücel Ünal, Sedat Yildiz
Nutritive Value Of Pastures In Kars District I. Botanical And Nutrient Composition At Different Stages Of Maturity, İsmai̇l Kaya, Ahmet Öncüer, Yücel Ünal, Sedat Yildiz
Turkish Journal of Veterinary & Animal Sciences
The objectives of this study were to examine the botanical composition and determine the nutritive value of pastures in 9 different locations in Kars district with respect to stages of maturity. Samples were collected bi-weekly from 21 May to 30 July 1999. The Gramineae, Leguminoseae and other plant families constituted 64.2, 22.8 and 13.0% of the plant population, respectively. There was a variation in the nutrient composition of samples collected from different locations (P < 0.05). Average dry matter (DM) content was 28.8% and concentrations of organic matter (OM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), nitrogen-free extract (NFE), ether extract (EE) and ash on a DM basis were 90.8, 15.3, 30.0, 57.6, 43.4, 2.0 and 9.2%, respectively. Stage of maturity altered nutrient composition (P < 0.5). Concentrations of OM, NFE and ash did not change, CP linearly decreased, and CF and NDF quadratically increased with advancing maturity. In conclusion, the Gramineae were the predominant flora of pastures in northeastern Turkey. Moreover, mathematical models developed to characterize changes in the nutrient composition of pastures with advancing maturity may help to improve current feeding strategies.
Cover And Contents
Turkish Journal of Veterinary & Animal Sciences
No abstract provided.
Cover And Contents
Turkish Journal of Veterinary & Animal Sciences
No abstract provided.
Cover And Contents
Turkish Journal of Veterinary & Animal Sciences
No abstract provided.
Secondary Metabolites From Phlomis Kotschyana, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Ali̇ Arslan Dönmez, Akito Nagatsu
Secondary Metabolites From Phlomis Kotschyana, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Ali̇ Arslan Dönmez, Akito Nagatsu
Turkish Journal of Chemistry
A lignan glycoside, syringaresinol-4',4''-O-di-\beta -D-glucopyranoside (1) (=liriodendrin), 4 phenylethanoid glycosides, acteoside (2), isoacteoside (3), forsythoside B (4) and leucosceptoside B (5), a caffeic acid ester, chlorogenic acid (6) and 2 iridoid glucosides, lamiide (7) and auroside (8), were isolated from the methanolic extracts of the aerial parts of Phlomis kotschyana along with an acetophenone glycoside, 4-hydroxyacetophenone 4-O-[6'-O-\beta -D-apiofuranosyl]-\beta -D-glucopyranoside (9). The structures of the isolated compounds were identified on the basis of spectroscopic (UV, IR, 1D- and 2D-NMR, and FAB-MS) methods.
Iridoid And Phenylethanoid Glycosides From Verbascum Lasianthum, Zeli̇ha Ş. Akdemi̇r, İ. İrem Tatli, Erdal Bedi̇r, Ikhlas A. Khan
Iridoid And Phenylethanoid Glycosides From Verbascum Lasianthum, Zeli̇ha Ş. Akdemi̇r, İ. İrem Tatli, Erdal Bedi̇r, Ikhlas A. Khan
Turkish Journal of Chemistry
Three iridoid glucosides, 8-O-acethylharpagide (1), harpagoside (2), and 6-O-vanilloylajugol (3), were isolated from the roots of Verbascum lasianthum Boiss. ex Bentham. In addition, 2 phenylethanoid glycosides, verbascoside {=acteoside, [\beta -(3,4-dihydroxyphenyl)-ethyl]-(3' -O-\alpha -L-rhamnopyranosyl)-(4' -O-caffeoyl)-\beta -D-glucopyranoside} (4) and poliumoside {= [\beta -(3,4-dihydroxyphenyl)-ethyl]-(3',6' -O-\alpha -L-dirhamnopyranosyl)-(4' -O-caffeoyl)-\beta -D-glucopyranoside} (5), were also isolated. The structures of all compounds were established by spectroscopic evidence (UV, IR, 1D and 2D NMR, LC-ESIMS). Compounds 2-5 demonstrated scavenging properties toward the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC autographic assays.
Numerical Simulation Of Soliton Pulse Propagation In Doped Optical Fibres By Finite-Difference Method, Adams Usman, Junaidah Osman, D. R. Tilley
Numerical Simulation Of Soliton Pulse Propagation In Doped Optical Fibres By Finite-Difference Method, Adams Usman, Junaidah Osman, D. R. Tilley
Turkish Journal of Physics
We report results of applications of explicit finite-difference schemes, viz. the combination of forward-difference and central-difference approximation schemes, to study a simulation of soliton pulse propagation in saturable optical fibres. The dynamic governing equation is the saturable nonlinear Schrödinger equation (SNLE). This equation thus far lacks analytical solution in the sense of the inverse scattering method, although an analytical solitary wave solution is available. We use the localized solution to generate data for simulations of fundamental and second order soliton pulse propagation. In addition, we check the numerical accuracy of the results by considering the physical significance of two conserved …
Modeling Relaxation Length And Half-Thickness Of Wood By Method Of Gamma Radiation, Louis E. Akpabio, Sunday E. Etuk, Samuel David Ekpe
Modeling Relaxation Length And Half-Thickness Of Wood By Method Of Gamma Radiation, Louis E. Akpabio, Sunday E. Etuk, Samuel David Ekpe
Turkish Journal of Physics
Relaxation lengths and half-thickness values of different types of wood were determined using gamma radiation from ^{60}C0 source. Results show that oxystigma (Oxystima spp) has the highest relaxation length of 23.810cm, while mangrove (Rhizoohora spp) has the least relaxation length of 1.247 cm. Results also show that Oxystima (Oxystima spp) has the highest half thickness value of 16.500 cm and Mangrove (Rhizophora spp) has the least half-thickness value of 0.864 cm. Two mathematical models have been developed for the prediction or determination of density \rho, variation with relaxation length and half thickness value of wood. A good agreement (greater than …
Formation And Elastic Behavior Of Lead-Magnesium Chlorophosphate Glasses, Hj. Ab. Aziz Sidek, S. P. Chow, Z. A. Talib, S. A. Halim
Formation And Elastic Behavior Of Lead-Magnesium Chlorophosphate Glasses, Hj. Ab. Aziz Sidek, S. P. Chow, Z. A. Talib, S. A. Halim
Turkish Journal of Physics
A series of ternary lead-magnesium chlorophosphate glasses, (PbCl_{2})_{x}(MgO)_{1 - x}(P_{2}O_{5})_{0.4}, of various compositions with 0.3 \le x \le 0.45 have been successfully prepared and their elastic properties have been characterized at room temperature. Results from the studies show that both the longitudinal and shear wave velocities decrease with increase of PbCl_{2} composition. The elastic constants C_{11}, C_{44} and Young's modulus show a decreasing trend while the elastic constant C_{12}, bulk modulus and Poisson's ratio show an increasing trend as the fraction of PbCl_{2} increases. This behavior of the elastic properties is related to the change in the structure of glasses …
The Born Scattering Amplitude Of A Non-Relativistic Spin One-Half Particle In An Aharonov-Bohm Potentia, Yousef Romia, Mohammad Shikakhwa
The Born Scattering Amplitude Of A Non-Relativistic Spin One-Half Particle In An Aharonov-Bohm Potentia, Yousef Romia, Mohammad Shikakhwa
Turkish Journal of Physics
The Born scattering amplitude of a non-relativistic spin one-half particle in an Aharonov-Bohm potential is calculated up to second order. It is demonstrated that perturbation theory works well for this model, in contrast with the case of scalar particles, thanks to the spin-magnetic moment interaction term. The first order amplitude is shown to coincide with the exact amplitude when expanded to the same order; the second order amplitude is finite and null. The polarized scattering cross section is found to be different from the unpolarized one only if the incident particle has a spin component perpendicular to the flux tube.
Quantum Statistical Entropy Of Sen Black Hole, Zhao Ren, Wu Yueqin, Zhang Lichun
Quantum Statistical Entropy Of Sen Black Hole, Zhao Ren, Wu Yueqin, Zhang Lichun
Turkish Journal of Physics
In this paper, by using quantum statistical methods, we directly obtain the partition function of Bose field and Fermi field on the background of the axisymmetrical Sen black hole. The difficult-to-solve wave equation is avoided. Then via the improved brick-wall method and membrane model, we calculate the entropy of Bose field and Fermi field of the black hole. We find that the entropy of the black hole is proportional to the area of the horizon. In our results, we do not encounter the left out term nor the divergent logarithmic term that appears in the original brick-wall method. The question …
E2/M1 Multipole Mixing Ratios Of Transitions In Erbium Isotopes, Harun Reşi̇t Yazar, İhsan Uluer
E2/M1 Multipole Mixing Ratios Of Transitions In Erbium Isotopes, Harun Reşi̇t Yazar, İhsan Uluer
Turkish Journal of Physics
Erbium isotopes (Z = 64) lie in the transitional region that occurs at the middle of the range of deformed nuclei. \gamma -ray E2/M1 mixing ratios for selected transitions in ^{166-168}Er are calculated in the proton-neutron interacting boson approximation(IBA-2). The results obtained for ^{166 -168}Er are reasonably in good agreement with the previous experimental and teoretical values.
Large Amplitude Wave Trains In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Large Amplitude Wave Trains In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Turkish Journal of Physics
Using ground-based neutron monitor data of Deep River, the high amplitude anisotropic wave train events (HAE) in cosmic ray intensity have been investigated during the period 1991--1994. It has been observed that the phase of diurnal anisotropy for majority of HAE cases remains in the same co-rotational direction, whereas for some HAE cases the phase of diurnal anisotropy has shifted to later hours. For the majority of HAE cases the amplitude of semi-diurnal anisotropy remains statistically the same, whereas the phase of semi-diurnal anisotropy for all HAE cases has shifted to later hours. Furthermore, for tri-diurnal anisotropy the phase shifts …
Structural And Magnetic Properties Of Co_{0.6}Znn_{0.4}Mn_{X}Fe_{2 - X}O_{4}, O.M. Hemeda
Structural And Magnetic Properties Of Co_{0.6}Znn_{0.4}Mn_{X}Fe_{2 - X}O_{4}, O.M. Hemeda
Turkish Journal of Physics
A series of Co-Zn ferrite samples substituted by Mn were prepared by the usual double sintering ceramic technique. The x-ray diffraction patterns of the samples confirmed the formation of single-phase spinel structure, and x-ray analysis supply data that suggests the cation distribution of the material. The tetrahedral and octahedral radius permits one to calculate the theoretical lattice parameter and the bond lengths Fe-O at A and B sites. The particle size of the given samples was measured from the Scherer equation and a correlation was found between particle size, and structural and magnetic properties. The XRF confirmed the presence of …
The Normal And Inverted Meyer-Neldel Rule In The Ac Conductivity, Fouad Abdel-Wahab
The Normal And Inverted Meyer-Neldel Rule In The Ac Conductivity, Fouad Abdel-Wahab
Turkish Journal of Physics
Recently, a new approach has been proposed for the correlated barrier hopping (CBH) model where the ac relaxation time is thought to obey the Meyer-Neldel (MN) rule. This approach gives quantitative agreement with some reliable published experimental data. We report on an experiment involving the characterization of the ac conductivity of Se-Te thin films over a wide range of frequencies and temperatures, carried out in order to confirm applicability of the MN rule to the ac conductivity. In addition to the normal MN rule, the inverted MN rule was observed.
Realizations Of The Osp(2,1) Superalgebra And Related Physical Systems, Hayri̇ye Tütüncüler, Ramazan Koç
Realizations Of The Osp(2,1) Superalgebra And Related Physical Systems, Hayri̇ye Tütüncüler, Ramazan Koç
Turkish Journal of Physics
Eigenvalues and eigenfunction of two-boson 2 \times 2 Hamiltonians in the framework of the superalgebra osp(2,1) are determined by presenting a similarity transformation. The Hamiltonians include two bosons and one fermion have been transformed in the form of the one variable differential equations and the conditions for its solvability have been discussed. It is observed that the Hamiltonians of the various physical systems can be written in terms of the generators of the osp(2,1) superalgebra and under some certain conditions their eigenstates can exactly be obtained. In particular, the procedure given here is useful in determining eigenstates of the Jaynes-Cummings …
The Riemann Zeta Function Applied On Glassy Systems And Neural Networks, Viorel L. Cartas
The Riemann Zeta Function Applied On Glassy Systems And Neural Networks, Viorel L. Cartas
Turkish Journal of Physics
Glassy systems and Neural networks share a simple model of study: the model of a set of N non interacting harmonic oscillators with energy. In this paper the author tries to describe these complex systems in order to find the energy involved. The mathematical method used is described in detail.
Analysis Of One-Nucleon Transfer Cross-Sections, A. K. A. R. Al-Farra
Analysis Of One-Nucleon Transfer Cross-Sections, A. K. A. R. Al-Farra
Turkish Journal of Physics
The angular distributions of ^{26}Mg(^3H,^2H)^{27}Mg and ^{30}Si(^3H,^2H)^{31}Si reactions have been successfully studied using distorted wave Born approximation (DWBA) calculations. The optical model potentials are taken to have Woods-Saxon, parity and spin-orbit interactions. The present analysis gives a satisfactory fit to the forward angle data but grossly over estimates the cross-sections in the backward regions. The spin-orbit potential provides the best description of the experimental data and is found to be necessary to account for the large-angle cross sections. The obtained values of the extracted spectroscopic factors are reasonable.
Exceptionaly Low Amplitude Anisotropic Wave Train Events In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Exceptionaly Low Amplitude Anisotropic Wave Train Events In Cosmic Ray Intensity, Rajesh K. Mishra, Rekha Agarwal Mishra
Turkish Journal of Physics
The unusually low amplitude anisotropic wave train events (LAEs) in cosmic ray intensity using the ground-based Deep River neutron monitor data has been studied during the period 1991--94. It has been observed that the phase of the diurnal anisotropy for majority of the LAE events remains in the corotational direction. However, for some of the LAE events the phase of the diurnal anisotropy shifts towards earlier hours. On the other hand, the amplitude of the semi-diurnal anisotropy remains statistically the same whereas, phase shift towards later hours; similar trend has also been found in case of tri-diurnal anisotropy. The interplanetary …