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2001

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Zeros Of Scattering Amplitude For A Spin-Dependent Gaussian Potential, Nilufar Farhat Hossain, Hasna Banu, A. K. Halder Jan 2001

Zeros Of Scattering Amplitude For A Spin-Dependent Gaussian Potential, Nilufar Farhat Hossain, Hasna Banu, A. K. Halder

Turkish Journal of Physics

In the proposed model, polarization in the scattering amplitude for a Gaussian potential including spin is considered. The problem of scattering amplitude is formulated in two different ways: the first and second Born approximations along with their high energy limits and the eikonal approximation including Wallace corrections. A comparison of the numerical zeros of the scattering amplitude computed in the above two approximations is studied in the complex momentum transfer plane. An analysis of the zero trajectories shows that the contribution of the spin part in the potential is quite significant at high energies whereas at low energies the spin-part …

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Beta Spectrometers With Surface Barrier Detector And Plastic Scintillator: Applications To ^{90}Sr,^{204}Tl,^{210}Pb And ^{14}C, Cüneyt Çeli̇ktaş Jan 2001

Beta Spectrometers With Surface Barrier Detector And Plastic Scintillator: Applications To ^{90}Sr,^{204}Tl,^{210}Pb And ^{14}C, Cüneyt Çeli̇ktaş

Turkish Journal of Physics

In this work, a comparison of responses between a spectrometer using Si Surface Barrier Detector (Si SBD) and a spectrometer using Plastic Scintillator (PS) is given. Experimental pulse height spectra of beta particles from ^{90}Sr,^{204}Tl,^{210}Pb and ^{14}C pure beta sources has been obtained separately. By comparing obtained spectra, the priority of obtaining the beta spectra among them is discussed. This work is related to the spectral response of beta spectrometers to pure beta sources.

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Features Of The Compound Multiplicity Of The Interactions Of ^{24}Mg And ^{28}Si Ions With Emulsion Nuclei At 4.5a Gev/C, N. N. Abd-Allah, M. Mohery Jan 2001

Features Of The Compound Multiplicity Of The Interactions Of ^{24}Mg And ^{28}Si Ions With Emulsion Nuclei At 4.5a Gev/C, N. N. Abd-Allah, M. Mohery

Turkish Journal of Physics

The present paper deals with the interactions of ^{24}Mg and ^{28}Si nuclei at 4.5A GeV/c with emulsion. Some characteristics of the compound multiplicity given by the numerical sum of grey and shower particles have been investigated. The obtained results indicate that the compound multiplicity distribution is consistent with KNO-Scaling and its width increases with the size of the projectile nucleus.The dependence of the average compound multiplicity on the numbers of black and the grey particles and the sum of them is obvious and the values of the slope has been found to be independent of the projectile nucleus.

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Multiparticle Equations For Scalar Particles, Valery Nikolaevich Kapshai, Alexander Ivanovich Fursin Jan 2001

Multiparticle Equations For Scalar Particles, Valery Nikolaevich Kapshai, Alexander Ivanovich Fursin

Turkish Journal of Physics

Multiparticle equations for scalar particles are derived in the framework of the Lagrangian formalism of field theory as a consequence of the Dyson-Schwinger equations for the generating functional of Green's functions. The general form of the n-particle equation is determined. The formula for the kernel of the equation is obtained. It makes possible to use the functional methods for the investigation of the equation. It is proven that the equation is correct in the lower orders for two-particle Green's functions.

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Mössbauer-Effect Study Of Fine Atomic Structure Of Fe-Ni-C Alloys, K. G. Binnatov, A. O. Mekhrabov Jan 2001

Mössbauer-Effect Study Of Fine Atomic Structure Of Fe-Ni-C Alloys, K. G. Binnatov, A. O. Mekhrabov

Turkish Journal of Physics

Fine atomic structure of Fe-Ni-C alloys containing of 30-36 wt. % Ni and 0.1-1.0 wt. % C have been analysed by means of a nuclear \gamma -resonance method. The alloys under investigation were in austenite phase. The study shows that the effective hyperfine magnetic field H_{eff} on the ^{57}Fe nuclei is affected by the presence of C atoms in Fe-Ni alloys and the mean value of H_{eff} fields increase with increasing of C element content in these alloys. It has been detected that increase in carbon content in Fe-Ni alloys leads to a broadening of Mössbauer absorption lines. On the …

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Cation Distribution And Magnetisation Study Of Nd^{+3} Substituted Zn-Mg Ferrites, B. P. Ladgaonkar, P. N. Vasambekar, A. S. Vaingankar Jan 2001

Cation Distribution And Magnetisation Study Of Nd^{+3} Substituted Zn-Mg Ferrites, B. P. Ladgaonkar, P. N. Vasambekar, A. S. Vaingankar

Turkish Journal of Physics

Polycrystalline ferrites Zn_{x}Mg_{1-x}Fe_{2-y}Nd_{y}O_{4} (x = 0.00, 0.20, 0.40, 0.80 and 1.00; y = 0.00, 0.05 and 0.10) were prepared by standard ceramic method. Thecompositions,oncharacterisation by X-ray diffraction, shows formation of single phase cubic spinels. Magnetic measurement of these composition shows increase in magnetic moment n_{\beta} with Zn^{2+} concentration up to x = 0.4 and decreases thereafter. This is attributed to the existence of locallised canted spin. The compositions for x = 0.8 and 1.0 shows paramagnetic behaviour at and above room temperature. The trivalent substitution of Nd^{3+} ion causes reduction in the magnetic moment. The cation distribution of the sytem …

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Effect Of Carrier Concentration Dependant Mobility On The Performance Of High Electron Mobility Transistors, Mustafa Erol Jan 2001

Effect Of Carrier Concentration Dependant Mobility On The Performance Of High Electron Mobility Transistors, Mustafa Erol

Turkish Journal of Physics

The influence of the sheet carrier concentration dependence on mobility on the performance of High Electron Mobility Transistor (HEMT) structures is theoretically modeled. The model basically takes into account both the drift and diffusion part of the overall drain current. The normalised drain current and normalised transconductance are found to be greatly affected by the carrier concentration dependant mobility.

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Factors Affecting Radon Concentration In Houses, Abdel-Latif Al-Sharif, Y. S. Abdelrahman Jan 2001

Factors Affecting Radon Concentration In Houses, Abdel-Latif Al-Sharif, Y. S. Abdelrahman

Turkish Journal of Physics

The dangers to the human health upon exposure to radon and its daughter products is the main motivation behind the vast number of studies performed to find the concentration of radon in our living environment, including our houses. The presence of radon and its daughter products in houses are due to various sources including building materials and the soil under the houses. Many factors affect radon concentration in our houses, the elevation above ground level,ventilation, building materials and room usage being among these factors. In our paper, we discuss the effect of elevation above ground level, room usage and ventilation …

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Cover And Contents Jan 2001

Cover And Contents

Turkish Journal of Physics

No abstract provided.

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Viscous Dissipation Of Magnetosonic Waves In Solar Corona, Belinda Kalomeni, D. Özlem Hürkal, E. Rennan Pekünlü, Kadri̇ Yakut Jan 2001

Viscous Dissipation Of Magnetosonic Waves In Solar Corona, Belinda Kalomeni, D. Özlem Hürkal, E. Rennan Pekünlü, Kadri̇ Yakut

Turkish Journal of Physics

Wave propagation and dissipation of magnetosonic waves are considered in an inhomogenous viscous coronal plasma permeated by a spatially varying magnetic field. In the linear magnetohydrodynamic approximation the dispersion relation yields two wave modes, fast and slow respectively. Depending on the physical parameters of the medium the damping length scales of the modes show varying behaviours. Damping length scales of the modes show sudden decrease at relevant heights. These drops may be due to phase mixing and resonance absorption. Wave flux density of the magnetosonic waves turns out to be of the order of 10^6 erg cm^{-2} s^{-1}. This is …

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Exciton Investigations And The Urbach Tails Of Gd Doped And Undoped Gase, Beki̇r Gürbulak Jan 2001

Exciton Investigations And The Urbach Tails Of Gd Doped And Undoped Gase, Beki̇r Gürbulak

Turkish Journal of Physics

Absorption measurements were carried out in GaSe and GaSe:Gd samples in temperature range 10-320 K in steps 10 K. The first and the second (n=1 and n=2) excitonic levels were marked. The first exciton energies for n=1 were calculated as 2.118, 2.008 eV in GaSe, and 2.125, 2.006 eV in GaSe:Gd at 10, 320 K and respectively. The second exciton energies for n=2 were calculated as 2.140, 2.125 eV in GaSe at 10, 80 K and 2.141, 2.120 eV in GaSe:Gd at 10, 120 K and respectively. Binding energies of GaSe and GaSe:Gd were calculated as (29.46\pm 1 and 21.33\pm …

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The Theoretical Analysis Of The Second Order Coherence G^{(2)}(\Tau) And Power Stabilization Of Two-Mode He-Ne Laser, Erol Taşal, M. Selami̇ Kiliçkaya Jan 2001

The Theoretical Analysis Of The Second Order Coherence G^{(2)}(\Tau) And Power Stabilization Of Two-Mode He-Ne Laser, Erol Taşal, M. Selami̇ Kiliçkaya

Turkish Journal of Physics

In this study, second-order coherence and its frequency-dependent characteristics and the photon statistical properties of the two-mode He-Ne laser field are investigated.

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A Theoretical Analysis Of Transverse Mode Control In Waveguide Gas Lasers, Erol Taşal, M. Selami̇ Kiliçkaya Jan 2001

A Theoretical Analysis Of Transverse Mode Control In Waveguide Gas Lasers, Erol Taşal, M. Selami̇ Kiliçkaya

Turkish Journal of Physics

Theoretical of multiple transverse mode laser oscillation involving spatially varying gain and loss are investigated. The effect of gain and loss distribution on mode competition is analyzed. A theoretical analysis of laser transverse mode competition is investigated from the perspective of the spetial overlap of modes with a transverse gain-loss distribution. The dominant mode of laser oscillation is the mode that is stable under small perturbations.

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Impurity Conductivity In Semiconductors Resulting From Radiant Excitation, Vakhab T. Toulanov, Aziza Sh. Davletova, Lesbek T. Tashimov, Kamila A. Ortaeva Jan 2001

Impurity Conductivity In Semiconductors Resulting From Radiant Excitation, Vakhab T. Toulanov, Aziza Sh. Davletova, Lesbek T. Tashimov, Kamila A. Ortaeva

Turkish Journal of Physics

This paper deals with the derivation of common formulae for induced impurity photosensibility with an arbitrary set of energy levels in the semiconductor gap. We give the expression for the real recombinational situation with two types of impurity levels as well. The basic properties and certain common peculiarities concerning induced photoconductivity in semiconductors are under consideration.

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Electrical Characterization Of Gate And Gate:Cu Semiconductor Compounds, Hüsnü Sali̇h Güder, Bahatti̇n Abay, Hasan Efeoğlu, Cevdet Coşkun, Şaki̇r Aydoğan, Yahya Kemal Yoğurtçu Jan 2001

Electrical Characterization Of Gate And Gate:Cu Semiconductor Compounds, Hüsnü Sali̇h Güder, Bahatti̇n Abay, Hasan Efeoğlu, Cevdet Coşkun, Şaki̇r Aydoğan, Yahya Kemal Yoğurtçu

Turkish Journal of Physics

Electrical properties of GaTe and GaTe:Cu binary compound semiconductors were investigated by Hall effect and resistivity measurements in the 77-320 K temperature range. Donor and acceptor densities, compensation ratios, acceptor ionization energies, valence band effective mass of holes and effective density of states in valence band were determined for the undoped and Cu doped samples using the single donor-single acceptor analysis of the hole concentration. Temperature coefficient of the hole mobility was determined and compared with related theories.

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Electron Impact Double Ionization Of Helium From [E, (3-1)E] Experiments}, Mevlut Dogan Jan 2001

Electron Impact Double Ionization Of Helium From [E, (3-1)E] Experiments}, Mevlut Dogan

Turkish Journal of Physics

Electron impact double ionization of helium has been observed in an [e,(3-1)e] experiment at an incident electron energy of 200 eV. 110 eV scattered and 10 eV ejected electrons are observed in coincidence without detection of the second ejected electron (1 eV). Present and previous observations are discussed.

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Urbach-Martienssen's Tail In Layered Ternary Semiconductor Tlgas_{2}, Bahatti̇n Abay, Hüsnü Sali̇h Güder, Hasan Efeoğlu, Yahya Kemal Yoğurtçu Jan 2001

Urbach-Martienssen's Tail In Layered Ternary Semiconductor Tlgas_{2}, Bahatti̇n Abay, Hüsnü Sali̇h Güder, Hasan Efeoğlu, Yahya Kemal Yoğurtçu

Turkish Journal of Physics

Dependence of the absorption coefficient on the photon energy and temperature near the fundamental absorption edge was measured for layered single crystal TlGaS_{2}. The exponentially increasing absorption tail was explained as an Urbach-Martienssen's (U-M's) tail for TlGaS_{2} samples in the 10-340 K temperature range. The characteristic Urbach's parameters such as steepness parameter [\sigma (T)] and Urbach's energy [(E_{u} = k_{B} T / \sigma )] were determined. Analyzing the temperature dependence of these parameters based on the general models, which takes into account the possible role of several different types of disorder, we conclude that the absorption process in the fundamental …

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Epilepsy In Saudi Children With Cerebral Palsy, Abdulsalam A. Al-Sulaiman Jan 2001

Epilepsy In Saudi Children With Cerebral Palsy, Abdulsalam A. Al-Sulaiman

Saudi Medical Journal

OBJECTIVE: To study the clinical characteristics, electroencephalographic and computerized axial tomography profile in Saudi children with cerebral palsy who suffer epilepsy in a university referral center. METHODS: A total of 113 patients with cerebral palsy and epilepsy was seen (67 boys, 46 girls) with an over all mean age 5.3 years (range .2-12 years) during the study period (January 1998 - December 1999). They all had clinical evaluation and standardized electroencephalographic studies interpreted by the same examiner. RESULTS: The main clinical features were language delay (61%), hypotonia (45%), hypertonia (38%), and behavioral abnormalities (41%). Seizure types included generalized in 96 …

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Prevalence Of Hypertension In Obese And Non-Obese Saudis, Mohsen A. El-Hazmi, Arjumand S. Warsy Jan 2001

Prevalence Of Hypertension In Obese And Non-Obese Saudis, Mohsen A. El-Hazmi, Arjumand S. Warsy

Saudi Medical Journal

OBJECTIVE: Obesity occurs at a high prevalence in the Saudi population. Studies in literature show that hypertension occurs more frequently in obese individuals.This study was designed to determine the prevalence of hypertension in obese Saudis in comparison with results obtained in non-obese individuals. METHODS: The screening involved a statistically designed household screening program. Only adults 14-70 years of age were included in the study. Blood pressure (systolic and diastolic) was measured when the individuals were in sitting position and height and weight were used to calculate Body Mass Index. All individuals with Body Mass Index > 30 were classified as obese …

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Epidemiology Of Bronchial Asthma Among School Boys In Al-Khobar City, Saudi Arabia, Kasim M. Al-Dawood Jan 2001

Epidemiology Of Bronchial Asthma Among School Boys In Al-Khobar City, Saudi Arabia, Kasim M. Al-Dawood

Saudi Medical Journal

OBJECTIVE: The objective of this cross-sectional study was to determine the prevalence of bronchial asthma among Saudi School boys at Al-Khobar city. METHODS: This is a cross-sectional study. The methodology included the distribution of a self administered questionnaire which was filled by the parents of 1482 school boys who satisfied the selection criteria of the study. RESULTS: The prevalence rate of Questionnaire Diagnosed Asthma and Physician Diagnosed Asthma were 9.5% and 8%. Questionnaire Diagnosed Asthma school boys and their parents suffered significantly higher rates of allergenic diseases and environmental factors (pets at home, passive smoking) than non Questionnaire Diagnosed Asthma. …

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Analysis Of False Positive And False Negative Cytological Diagnosis Of Breast Lesions, Awatif A. Jamal, Ibrahim Mansoor Jan 2001

Analysis Of False Positive And False Negative Cytological Diagnosis Of Breast Lesions, Awatif A. Jamal, Ibrahim Mansoor

Saudi Medical Journal

OBJECTIVE: To study the reasons for interpretive errors in false negative and false positive diagnosis of breast carcinoma on fine needle aspiration cytology material. METHODS: We reviewed only those cases in which cytohistological discrepancies were found, where the cytologic material was abnormal and to some extent misinterpreted or both. RESULTS: There was only one false negative case (false negative fraction 0.32%) proved histologically as ductal carcinoma and four false positive cases (false positive fraction 1.2%); 2 fibroadenoma; 1 fibrocystic disease; and 1 stromal fibrosis. Smears of the two false positive fibroadenoma cases showed very high cellularity, overcrowded clusters and frequent …

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Computer Graphics Optique: Optical Superposition Of Projected Computer Graphics, Aditi Majumder Jan 2001

Computer Graphics Optique: Optical Superposition Of Projected Computer Graphics, Aditi Majumder

Link Foundation Modeling, Simulation and Training Fellowship Reports

We present some ideas and demonstrations for a hybrid projector-based rendering and display technique we call Computer Graphics Optique. Instead of partially overlapping projected images to achieve a wide-area display, we completely overlap projected images on top of each other to achieve the addition of light and color in an "optical composition buffer''. The idea is to use the optical composition to replace some analytical computation, to increase rendering speed, gain flexibility, intensity range, and intensity resolution. Where projector-based displays are appropriate, potential uses include the optical realization of certain effects normally requiring a digital accumulation buffer, the optical composition …

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Computer Graphics Optique: Optical Superposition Of Projected Computer Graphics, Aditi Majumder Jan 2001

Computer Graphics Optique: Optical Superposition Of Projected Computer Graphics, Aditi Majumder

Link Foundation Modeling, Simulation and Training Fellowship Reports

We present some ideas and demonstrations for a hybrid projector-based rendering and display technique we call Computer Graphics Optique. Instead of partially overlapping projected images to achieve a wide-area display, we completely overlap projected images on top of each other to achieve the addition of light and color in an "optical composition buffer''. The idea is to use the optical composition to replace some analytical computation, to increase rendering speed, gain flexibility, intensity range, and intensity resolution. Where projector-based displays are appropriate, potential uses include the optical realization of certain effects normally requiring a digital accumulation buffer, the optical composition …

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Enhancing Training And Presence In Virtual Environments Using Passive Haptics, Brent E. Insko Jan 2001

Enhancing Training And Presence In Virtual Environments Using Passive Haptics, Brent E. Insko

Link Foundation Modeling, Simulation and Training Fellowship Reports

One of the worst virtual environment experiences is to virtually contact something and feel nothing. Visual-haptic sensory conflicts are normally dominated by visual perception. Therefore, augmenting a high-fidelity visual virtual environment with low-fidelity haptic objects, called passive haptics, should markedly improve both sense of presence and task training effectiveness. Testing these hypotheses, I found adding a 1.5 inch physical ledge to a visual-cliff virtual environment increased participants' sense of presence as measured by subjective questionnaires, observed participant behaviors, and physiological responses. I next examined memory model creation and training effectiveness for a navigation task in a virtual environment with and …

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Teaching The Law Of Race (Book Review), Anthony V. Alfieri Jan 2001

Teaching The Law Of Race (Book Review), Anthony V. Alfieri

Articles

No abstract provided.

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Race Prosecutors, Race Defenders, Anthony V. Alfieri Jan 2001

Race Prosecutors, Race Defenders, Anthony V. Alfieri

Articles

No abstract provided.

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Crime Control And Feminist Law Reform In Domestic Violence Law: A Critical Review, Donna Coker Jan 2001

Crime Control And Feminist Law Reform In Domestic Violence Law: A Critical Review, Donna Coker

Articles

No abstract provided.

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Multiracial Matrix: The Role Of Race Ideology In The Enforcement Of Antidiscrimination Laws, A United States-Latin America Comparison, Tanya K. Hernandez Jan 2001

Multiracial Matrix: The Role Of Race Ideology In The Enforcement Of Antidiscrimination Laws, A United States-Latin America Comparison, Tanya K. Hernandez

Faculty Scholarship

This Article examines the role of race ideology in the enforcement of antidiscrimination laws. Professor Hernandez demonstrates the ways in which the U.S. race ideology is slowly starting to resemble the race ideology of much of Latin America. The evolving U.S. race ideology is a multiracial matrix made up of four precepts: (1) racial mixture and diverse racial demography will resolve racial problems; (2) fluid racial classification schemes are an indicator of racial progress and the colorblind abolition of racial classifications an indicator of absolute racial harmony; (3) racism is solely a phenomenon of aberrant racist individuals; and (4) focusing …

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2001-2002 Undergraduate Bulletin, Rochester Institute Of Technology Jan 2001

2001-2002 Undergraduate Bulletin, Rochester Institute Of Technology

RIT Digital Archives

No abstract provided.

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Glass Transition Behavior Of Pmma Thin Films, Moses T. Kabomo, Frank D. Blum Jan 2001

Glass Transition Behavior Of Pmma Thin Films, Moses T. Kabomo, Frank D. Blum

Chemistry Faculty Research & Creative Works

In the last decade there has been an increased interest in the study of the properties of supported thin polymer films. This has been prompted by the incorporation of thin films into device applications and many other technologies. Although not without controversy, a large body of experimental work indicates departures from bulk behavior by thin films. Strong evidence from both theoretical and experimental work shows that the interaction of polymer with a substrate alters the polymer conformation and mobility. A variety of techniques has been employed to probe the mobility of thin supported polymer films. Some of these techniques indirectly …

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