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Full-Text Articles in Physical Sciences and Mathematics

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.


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 …


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 …


Development Of A Basic Gis Database For The Yeşilırmak Watershed Provinces Using Satellite Images And Other Data, Hülya Yildirim, Erhan Alparslan, Mehmet Emi̇n Özel, Ci̇hangi̇r Aydöner, Samuray Eli̇taş, Nalan Jale Di̇van, Mehmet Dağci, Asli Süha Dönertaş Jan 2001

Development Of A Basic Gis Database For The Yeşilırmak Watershed Provinces Using Satellite Images And Other Data, Hülya Yildirim, Erhan Alparslan, Mehmet Emi̇n Özel, Ci̇hangi̇r Aydöner, Samuray Eli̇taş, Nalan Jale Di̇van, Mehmet Dağci, Asli Süha Dönertaş

Turkish Journal of Earth Sciences

Remote-sensing and geographic-information-systems (GIS) techniques were jointly used in this study to establish a GIS database system for the Yeşilırmak watershed provinces, which include Amasya, Tokat, Çorum, Yozgat and Samsun. Composite multicolour images (down to 6 m resolution) from the LANDSAT TM and Indian IRS C/D satellites, land-use/land-cover maps derived from these images, road networks, soil information, digital terrain model, slope and aspect information derived from digital elevation data and meteorological data at province level are the major constituents of this database. A 'project office' has been established with trained personnel at each province centre to effectively use the resultant …


Post-Collisional Magmatism On The Northern Margin Of The Taurides And Its Geological Implications: Geology And Petrology Of The Yahyalı-Karamadazı Granitoid, Gonca Gençali̇oğlu Kuşcu, M. Cemal Göncüoğlu, İlkay Kuşcu Jan 2001

Post-Collisional Magmatism On The Northern Margin Of The Taurides And Its Geological Implications: Geology And Petrology Of The Yahyalı-Karamadazı Granitoid, Gonca Gençali̇oğlu Kuşcu, M. Cemal Göncüoğlu, İlkay Kuşcu

Turkish Journal of Earth Sciences

The Karamadazı Granitoid (Yahyalı-Kayseri) is a typical example of bimodal magmatism on the northern margin of the Eastern Tauride belt. The Karamadazı Granitoid intrudes the Palaeozoic-Mesozoic Yahyalı metamorphic rocks and is unconformably overlain by Upper Maastrichtian clastics. It consists of granodiorite-quartz diorite as the main intrusive phase, and includes leucogranites and aplitic dykes in its marginal parts. Samples from the Karamadazı Granitoid are calc-alkaline and calcic in character. The granodiorites are mainly metaluminous, whereas leucogranites and aplites are weakly peraluminous in nature. Plots of major-element oxides against SiO2 indicate a poor fractionation trend for the granodiorites. The leucogranites represent highly …


Metamorphic And Tectonic Evolution Of The Hırkadağ Block, Central Anatolian Crystalline Complex, Donna L. Whitney, Yildirim Di̇lek Jan 2001

Metamorphic And Tectonic Evolution Of The Hırkadağ Block, Central Anatolian Crystalline Complex, Donna L. Whitney, Yildirim Di̇lek

Turkish Journal of Earth Sciences

The Hırkadağ metamorphic block is a NE-SW-trending horst structure that is part of the Kırşehir Massif in the Central Anatolian Crystalline Complex (CACC). Along its southwestern margin, the block contains upper amphibolite facies metapelitic rocks that record peak metamorphic conditions of 670-710 °C, ~ 7 kbar, as determined by garnet-biotite geothermometry and garnet-sillimanite-plagioclase-quartz, garnet-rutile-sillimanite-ilmenite-quartz, and garnet-rutile-ilmenite-plagioclase-quartz geobarometry. A clockwise pressure-temperature path is inferred from thermobarometric results and analysis of reaction textures among aluminous phases. Following this medium-pressure metamorphism, low-pressure - high-temperature metamorphism resulted in widespread replacement of garnet by cordierite + spinel + sillimanite, partial replacement of spinel by corundum, …


Repetitive Subtidal-To-Coastal Sabkha Cycles From A Lower-Middle Miocene Marine Sequence, Eastern Sivas Basin, Faruk Ocakoğlu Jan 2001

Repetitive Subtidal-To-Coastal Sabkha Cycles From A Lower-Middle Miocene Marine Sequence, Eastern Sivas Basin, Faruk Ocakoğlu

Turkish Journal of Earth Sciences

In the study area, southeast of Zara in the Sivas Basin, the Lower-Middle Miocene marine Karacaören Formation consists of a succession of marine sedimentary rocks deposited within two trangressive-regressive cycles. The present study focuses on the facies characteristics, cyclic nature, and significance of the basin-wide distribution of a 100-m-thick gypsiferous sedimentary package overlying an otherwise transgressive segment of the lower sequence, within a marine setting. The typical lithologic expression of the studied sedimentary interval comprises generally fossiliferous mudstones, rare algal limestones and nodular gypsum. Detailed sedimentological observations, combined with palaeontological evidence, indicate that the mudstone intervals were deposited in a …


Stratigraphy, Geochemistry And Depositional Environment Of The Celestine-Bearing Gypsiferous Formations Of The Tertiary Ulaş-Sivas Basin, East-Central Anatolia (Turkey), Erdoğan Teki̇n Jan 2001

Stratigraphy, Geochemistry And Depositional Environment Of The Celestine-Bearing Gypsiferous Formations Of The Tertiary Ulaş-Sivas Basin, East-Central Anatolia (Turkey), Erdoğan Teki̇n

Turkish Journal of Earth Sciences

Celestine-bearing evaporite mineralization is widespread in the Tertiary evaporitic units of the Ulaş-Sivas Basin, east-central Anatolia. The oldest deposition of gypsum, which is of laminated character, occurred in a shallow inner-lagoonal environment or in depressions during Late Eocene regression. Thick gypsum and overlying beds composed of alternating bedded, nodular gypsum and sandstone developed in coastal sabkhas and abandoned channels within a meander-river complex during Oligocene time. The last occurrence of evaporitic units, namely massive and bedded gypsum alternating with sandstones and fossiliferous limestones, resulted from limited marine transgression of an Early Miocene sea along the southern margin of the Sivas …


The June 6, 2000, Orta (Çankırı, Turkey) Earthquake: Sourced From A New Antithetic Sinistral Strike-Slip Structure Of The North Anatolian Fault System, The Dodurga Fault Zone, Ali̇ Koçyi̇ği̇t, Bora Rojay, Mustafa Ci̇han, Arda Özacar Jan 2001

The June 6, 2000, Orta (Çankırı, Turkey) Earthquake: Sourced From A New Antithetic Sinistral Strike-Slip Structure Of The North Anatolian Fault System, The Dodurga Fault Zone, Ali̇ Koçyi̇ği̇t, Bora Rojay, Mustafa Ci̇han, Arda Özacar

Turkish Journal of Earth Sciences

The İsmetpaşa-Kargı section of the North Anatolian Fault System (NAFS) consists of six subfault zones, namely the Eskipazar, the Ulusu, the Tosya, the Çerkeş-Kurşunlu, the Devrez and the newly detected Dodurga fault zone (DFZ). Together these fault zones form a well-developed dextral strike-slip-faulting pattern, in which the DFZ is an antithetic secondary strike-slip component, indicated by focal-mechanism solutions of moderate and large earthquakes that have occurred in the İsmetpaşa-Kargı section of the NAFS. The DFZ is a ~36-km-long, ~N-S-trending strike-slip structure located in the area between Saçak village in the north and Kösrelik village in the south. Pre-Upper Pliocene rocks …


Characteristics Of The Weathering Zones Developed Within The Tuffs Of The Midas Monument, Tamer Topal, Burak Sözmen Jan 2001

Characteristics Of The Weathering Zones Developed Within The Tuffs Of The Midas Monument, Tamer Topal, Burak Sözmen

Turkish Journal of Earth Sciences

The Midas monument, an impressive cult facade located in the southern part of the Eskişehir province in central Anatolia, Turkey, was made within tuffs (white and pink), which now have deterioration problems. In this study, the depth and characteristics of the weathering zones that have developed in the white and pink tuffs have been investigated through thin-section studies, X-ray powder diffractometry, methylene blue adsorption tests, major-element analyses, and some index parameters. It has been determined that the feldspar minerals are mechanically fractured due to weathering. The tuffs contain small amounts of clay minerals. An approximately 1-cm-thick silica-rich zone has developed …


Tectonic Implications Of Some Cretaceous Pillow Basalts From The North Anatolian Ophiolitic Mélange(Central Anatolia-Turkey) To The Evolution Of Neotethys, Bora Rojay, Kenan M. Yaliniz, Demi̇r Altiner Jan 2001

Tectonic Implications Of Some Cretaceous Pillow Basalts From The North Anatolian Ophiolitic Mélange(Central Anatolia-Turkey) To The Evolution Of Neotethys, Bora Rojay, Kenan M. Yaliniz, Demi̇r Altiner

Turkish Journal of Earth Sciences

The most widespread blocks within the North Anatolian ophiolitic mélange of central Anatolia (Turkey) are ophiolitic fragments, Jurassic-Cretaceous carbonate blocks and pillow basalts. The blocks of pillow basalts have an immobile trace-element geochemistry that is characteristic of ocean-island alkali basalts. An N-MORB-normalized spider diagram shows a distinctive enrichment of most incompatible trace elements and exhibits a far greater range of absolute abundances than N-MORB. Selected incompatible-element contents and ratios of basalts show high Ba/Nb (~8),low Zr/Nb(~5)and low La/Nb(~0.5)relative to N-MORB. The presence of thin-shelled \"Protoglobigerina\" and Cadosina associated with miliolids and epistominid foraminifers indicates that the age of the pink …


Geochemistry And Mineralogy Of The Skarns In The Çelebi District, Kırıkkale, Turkey, İlkay Kuşcu Jan 2001

Geochemistry And Mineralogy Of The Skarns In The Çelebi District, Kırıkkale, Turkey, İlkay Kuşcu

Turkish Journal of Earth Sciences

The Çelebi district is well known for its polymetallic Fe-W and Cu vein ores. These ores are hosted by calcic skarn zones, which are broadly classified as \"intrusive around skarn\" type. Both exoskarns (pyroxene-garnet) and endoskarns (epidote-pyroxene) occur in the district. The formation of endoskarns is manifested by complete replacement of plagioclase by epidote and pyroxene; the epidotized granitoids are regarded as incipient and/or early metasomatic products. The abundance of pyroxene in endoskarns tends to increase with plagioclase content and within the groundmass of the granitoids towards exoskarn zones. The increase in pyroxene is also coincident with the formation of …


A Proposal For A Method To Establish Natural-Hazard-Based Land-Use Planning: The Adapazarı Case Study, Alper Çabuk Jan 2001

A Proposal For A Method To Establish Natural-Hazard-Based Land-Use Planning: The Adapazarı Case Study, Alper Çabuk

Turkish Journal of Earth Sciences

As a result of recent disasters in northwest Turkey (Marmara earthquake August 17, 1999/Düzce earthquake November 12, 1999), many buildings collapsed and many people experienced physical and mental problems. We can suppose that the problems caused by these earthquakes will be solved in the future, but geological studies show that the problems will not disappear in that many scientists are predicting a new disaster that will affect the same region. A design of natural-hazard land-use planning for minimising the consequences of recent and possible earthquakes is presented herein. The Adapazarı case is used to demonstrate the fundamentals of this study. …


Obituary, Aral İ. Okay, M. Cemal Göncüoğlu Jan 2001

Obituary, Aral İ. Okay, M. Cemal Göncüoğlu

Turkish Journal of Earth Sciences

No abstract provided.


Field And Polarization Effects Arising In Neutrino-Lepton Processes In A Magnetic Field, V. A. Gusseinov Jan 2001

Field And Polarization Effects Arising In Neutrino-Lepton Processes In A Magnetic Field, V. A. Gusseinov

Turkish Journal of Physics

We discuss the effects arising in the neutrino-lepton processes (\nu_{\mu}+e^{-} \rightarrow \nu_{e}+\mu^{-} and \overline{\nu}_{e}+e^{-}\rightarrow\overline{\nu}_{\mu}+\mu^{-}) in a constant uniform magnetic field in the framework of the Weinberg-Salam-Glashow model. It is shown that in the case of a superstrong magnetic field and for the muon producing on the ground Landau level the leading term of the cross section asymptotics of the \nu_{\mu}-process does not depend on the field intensity and it effectively describes the one-dimensional free process. In the \nu_{\mu}-process the muons with the spins oriented opposite to the direction of the field are mostly produced. The electrons with the spins oriented …


The Resonance Bremsstrahlung Of A Fast Charged Particle In A Medium, Khamidbi M. Beshtoev Jan 2001

The Resonance Bremsstrahlung Of A Fast Charged Particle In A Medium, Khamidbi M. Beshtoev

Turkish Journal of Physics

The bremsstrahlung of a fast charged particle in the medium with dielectric permittivity \epsilon at velocities v \ge \frac{c}{n} (\mbox{Re}\epsilon = n^2) was considered. Bremsstrahlung radiation has singularity at \beta = \frac{1}{n \cos\theta} (\beta = \frac{v}{c}, \theta is an angle of the bremsstrahlung.) and is interpreted as resonance bremsstrahlung with the width characterized by Im\epsilon = \epsilon_2; and smaller \epsilon_2 is, the higher the peak of the resonance. The angle distribution of the bremsstrahlung is determined by \cos \theta = \frac{1}{n\beta} and \theta coincides with the angle of Cherenkov radiation. At \beta = \frac{1}{n} the resonance bremsstrahlung goes in the …


Properties Of Mos Capacitors Produced On Sige Formed By Ge-Implanted Si, M. Şahi̇n, Serhat Özder, Raşi̇t Turan Jan 2001

Properties Of Mos Capacitors Produced On Sige Formed By Ge-Implanted Si, M. Şahi̇n, Serhat Özder, Raşi̇t Turan

Turkish Journal of Physics

Metal-oxide-semiconductor (MOS) capacitors fabricated on Ge-implanted Si have been investigated by using C-V and G-V measurements. The control sample on pure Si substrate yielded normal C-V and G-V characteristics. The Ge-implanted MOS samples exhibited anomalous C-V and G-V behavior. The C-V curves of the samples were strongly frequency dependent both in the accumulation and inversion regions. They shift almost in parallel to higher values with decreasing frequency, reaching the oxide capacitance value in the quasi-static (QS) measurement. A band structure and equivalent circuit model were introduced to explain this and other features of the experimental observations. It is shown that …


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 …


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.


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.


Effect Of Flux Re-Distribution On Resistivity In Granular Ybco, Muhammad Muneeb Asim, Syed Khurshid Hasanain Jan 2001

Effect Of Flux Re-Distribution On Resistivity In Granular Ybco, Muhammad Muneeb Asim, Syed Khurshid Hasanain

Turkish Journal of Physics

Dc resistivity of a zero-field cooled YBCO was previously studied as a function of angle between applied field and transport current. The resistivity followed a sin^{2}\theta variation that was understood as a consequence of Lorentz force like effect. The resistivity deviated from the harmonic curve giving a minimum at low angles before following the true sin^{2}\theta behavior. The angle corresponding to minimum voltage \theta_{min} has been thoroughly studied in this paper as a function of applied field, transport current and temperature. sin^{2}\theta behavior of resistivity is not affected by the fields below Hc1 at their respective temperatures. The angle \theta_{min} …


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 …


The Temperature Dependence Of Dark Conductivity In Hydrogenated Amorphous Sin_X Films, Hüseyi̇n Tolunay, İlker Ay Jan 2001

The Temperature Dependence Of Dark Conductivity In Hydrogenated Amorphous Sin_X Films, Hüseyi̇n Tolunay, İlker Ay

Turkish Journal of Physics

Thin film samples of hydrogenated amorphous silicon nitride with varying nitrogen content were prepared by conventional plasma deposition from a mixture of SiH_4 and NH_3 . The dark conductivity (\sigma_d) of the films have been measured in the temperature range 420 K - 100 K. The conductivity is thermally activated with a single activation energy down to 250 K and conduction is dominated by electrons in extended states. A strong decrease is observed sigma _d when the nitrogen content is increased.


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 …


On The Statistical Properties Of A Q-Oscillator, Abdullah Algin Jan 2001

On The Statistical Properties Of A Q-Oscillator, Abdullah Algin

Turkish Journal of Physics

Several statistical properties of the Coon-Baker-Yu (CBY) q-oscillator algebra are discussed. Particular emphasis is given to a careful derivation of second quantized particle statistics obtained via the CBY q-oscillator. It is outlined that, beside other limiting cases, the limit q = 0 of the CBY q-oscillator gives the Cuntz oscillator and the Fock space properties of both of these oscillators lead to various interesting results.


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.


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.


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.


Optical Absorption And Photoluminescence Measurements In Inp And Inp:Fe Bulk Crystals And Inspection Of The Relations Between These Measurements, Seydi̇ Doğan, Sebahatti̇n Tüzemen, Beki̇r Gürbulak, Aytunç Ateş, Muhammet Yildirim Jan 2001

Optical Absorption And Photoluminescence Measurements In Inp And Inp:Fe Bulk Crystals And Inspection Of The Relations Between These Measurements, Seydi̇ Doğan, Sebahatti̇n Tüzemen, Beki̇r Gürbulak, Aytunç Ateş, Muhammet Yildirim

Turkish Journal of Physics

Optical absorption and photoluminescence (PL) measurements were carried out in both undoped and Fe-doped samples and the effect of Fe doping on absorption and PL spectra were studied. The results show that Fe or Fe-related defects behave as non-radiative recombination centers in InP. This is very important from the point of view that the control of minority carrier lifetime is possible. On the other hand, comparative analysis of the PL results with the optical absorption data show that quantitative assessment of relative PL intensities is possible with respect to Fe concentrations.


Directional Solidification Of Pure Succinonitrile And Succinonitrile- Salol Alloys, İbrahi̇m Karaca, Emi̇n Çadirli, Hasan Kaya, Necmetti̇n Maraşli Jan 2001

Directional Solidification Of Pure Succinonitrile And Succinonitrile- Salol Alloys, İbrahi̇m Karaca, Emi̇n Çadirli, Hasan Kaya, Necmetti̇n Maraşli

Turkish Journal of Physics

Pure succinonitrile (SCN) and succinonitrile-salol alloys with four different concentrations of salol were unidirectionally solidified at five different growth rates in a temperature gradient. The microstructure parameters, viz., the primary dendrite arm spacing \lambda _{1}, dendrite tip radius R and mushy zone depth d, were measured. The dependence of the microstructure parameters on the solidification parameters for pure SCN and SCN-Salol alloys were determined via linear regression analysis. The results are compared with published data.