Physical Sciences and Mathematics Commons^™

Magnetic Domain Structures In As-Quenched And Annealed Fe_{78}B_{13}Si_9 Metallic Glass Ribbons, Yücel Bi̇rol

Turkish Journal of Physics

Among various soft magnetic materials, ferromagnetic glasses are superior to their crystalline counterparts as they possess no magnetocrystalline anisotropy owing to a non-crystalline structure. However, ferromagnetic glasses carry residual stresses and thus anisotropies of magnetostrictive origin in the as-quenched state. These stresses have an adverse effect on the magnetic softness and should be relieved in order to improve magnetic performance, particularly in magnetostrictive alloys. In the present work, the domain structures of Fe$_{78}$B$_{13}$Si$_9$ metallic glass, a highly magnetostrictive alloy, are characterized in the as-quenched and annealed states. The annealing treatments were carried out over a wide temperature range extending from …

Economic Analysis And Comparison Of Two Solar Energy Systems With Domestic Water Heating Systems, R. Kayali

Turkish Journal of Physics

In this work, an economic analysis of different types of thermosiphons and geysers and flat plate collectors and solar ponds employeed in conventional solar energy systems used in houses is analized and the results obtained for these systems are compared with each other. These comparisons show that when the inflation rate is 50\% or less solar energy systems are more economical than the other conventional systems, except for conventional systems in which solid fuels are used. If the calculations are done assuming that the consumer credit interest rate varies between 55-70\%, it is seen that solar energy systems will only …

Domain Structures Of Epitaxial Perovskite Ferroelectric Films: Part I. Theory, S. Pamir Alpay, Alexander L. Roytburd

Turkish Journal of Physics

Possible equilibrium domain structures due to elastic interactions between the film and the substrate as a result of a cubic-tetragonal transformation observed in epitaxial perovskite ferroelectric films are analyzed. Domain structures are compared in terms of their elastic energies. The formation of both two- and three-domain states is taken into account. Maps which shows domain stability regions are developed in coordinates of misfit strain and tetragonality of the lattice of the ferroelectric phase.

Observation Of Events At Very High Q^2 In E^+P Collisions At Hera, A. Wagner

Turkish Journal of Physics

Data collected at the $e^+p$ collider HERA at DESY by the experiments H1 and ZEUS have allowed to probe a previously inaccessible domain of very large $Q^2$ in deep-inelastic $ep$ scattering. For $Q^2 > 15000 GeV^2$ both experiments see more events than expected assuming the Standard Model of deep-inelastic scattering. In this report the observed events, the theoretical expectations and their comparison are discussed.

A Review Of E^+E^- Linear Colliders, D. Trines

Turkish Journal of Physics

No abstract provided.

Testing Deca-Tev Unified Compositeness At The 4 Tev \Mu_+\Mu_-Colliders, Vasily V. Kabachenko, Yury F. Pirogov

Turkish Journal of Physics

In the framework of the unified compositeness of leptons, quarks and Higgs bosons, the hidden local symmetry $\hat H_{loc}=SU(2)_L\times U(1)_Y$ with the heavy composite vector bosons, in addition to the SM gauge bosons, is briefly described. Supplementary hypothesis of the vector boson dominance (VBD) of the SM gauge interactions is considered. It is argued that this should produce the universal dominant residual interactions of the SM composite particles, i.e., all of the fermions and Higgs bosons. Restrictions on the universal residual fermion-fermion, fermion-boson and boson-boson interactions due to the VBD are investigated. Manifestations of the residual interactions at the 4~TeV …

A Proposal For A Measurement Of The Nucleon Form Factors At An Asymmetric E^+E^- Linac-Ring Collider, R. Baldini, C. Bini, P. Patteri

Turkish Journal of Physics

The neutron electromagnetic form factors have been measured for the first time in the time-like region in the $Q^2$ range between 3.6 and 6 $GeV^2$ by the FENICE experiment. The results show some unexpected features. First the neutron magnetic form factor turns out to be larger than the proton one, the neutron electric form factor being negligible. Then there are indications of a narrow structure very near the $N\overline{N}$ threshold, in the e^+e^- multihadronic annihilation. A new, high statistics experiment is needed to clarify the indications. An asymmetric, unconventional, linac-storage ring collider is proposed, using one of the existing high …

Main Parameters Of Linac-Ring Type E-Nucleus And \Gamma-Nucleus Colliders, Ş. Turköz

Turkish Journal of Physics

The main parameters of linac-ring type e-nucleus and $\gamma $-nucleus colliders are considered. It is shown that the reasonable luminosities at the multi-TeV energies can be achieved.

Production Of Susy Particles In Polarized \Gammap Collisions, A. Kandemi̇r

Turkish Journal of Physics

We discuss the production of several SUSY particles in the high energy collisions of the real photons off the protons within the MSSM. The polarizations of the colliding beams are also considered. The discovery mass limits for the squark and gluinos are presented and we conclude that the capacity of the future TeV scale $\gamma p$ colliders is quite promising in the search for SUSY particles.

Resummation Of Ir Renormalons In A Single Meson Photoproduction, Shahin S. Agaev

Turkish Journal of Physics

Single pseudoscalar and vector mesons hard semi-inclusive photoproduction $\gamma h\rightarrow MX $ via higher twist mechanism is calculated using the QCD running coupling constant method. It is proved that in the context of this method a higher twist contribution to the photoproduction cross section cannot be normalized in terms of the meson electromagnetic form factor. The structure of infrared renormalon singularities of the higher twist subprocess cross section and the resummed expression (the Borel sum) for it are found. Comparisons are made with earlier results, as well as with leading twist cross section. Phenomenological effects of studied contributions for $\pi, …

Photoconductivity Studies Of Crystalline Si:H P-I-N, Ruhi Kaplan, Bengü Kaplan

Turkish Journal of Physics

Optically modulated photoconductivity (PC) properties of hydrogenated crystalline silicon (c-Si:H) with p-i-n junctions were investigated by frequency-resolved spectroscopy in the temperature range 20-290 K. The PC lifetime measurements of c-Si:H p-i-n show a second lifetime distribution which only dominates at low temperature under low illumination levels of excitation. Unlike the room temperature single lifetime distribution seen in c-Si:H p-i-n, the maximum of this second lifetime distribution shifts to longer times when the excitation intensity decreases, which reconciles with non-geminate pair recombination and thus the distant-pair model. In addition to lifetime measurements, the direct current-voltage (I-V) characteristics, the excitation light intensity- …

Multiple Scales Method For A Matrix Kdv Equation, Mehmet Naci Özer

Turkish Journal of Physics

In this paper the method of multiple scales is used to derive an integrable matrix non-linear Schrödinger equation (MNLS) as an amplitude equation from the Matrix Korteweg-de Vries equation (MKdV) associated with symmetric spaces. Then the integrability of the MNLS equation is deduced by the derivation of the spectral problem for the MNLS equation from the spectral problem for the MKdV equation.

The Green Dyadic Formulation For Radiation Problems With Arbitrary Sources Embedded In Stratified Multi-Layer Structures : Application To Molecular Fluorescence Problems, Robert Lyle Hartman

Dissertations and Theses

The Green Dyadic method for computing fields due to current sources between parallel interfaces of dielectric materials is studied. Computer implementation of the method as presented in a well-known article leads to the conclusion that significant errors are present. Two dissimilar methods of solution lead to corrected formulations which are shown to be equivalent. The same correction is found in the research literature. For confirmation, computations are performed in examples involving an emitting dipole by both the Green dyadic method and Sommerfeld' s Hertz vector method. Finally, the computational examples are used to compute fluorescence decay rates for emitting dipoles …

Spectroscopy Of Charge-Coupled Devices, Lars Mündermann

Dissertations and Theses

A systematic study of persistent, or residual, images occurring in CCD imagers and a systematic study of dark current generation in CCD imagers are presented. These effects are a source of unwanted signal in frames, and should be considered where very exact, low light-level signal processing is necessary. For both studies explanatory models and statistical analysis techniques have been developed which enable the derivation of the densities and the characteristic energies. Furthermore the importance of understanding these phenomena in the context of today's low light-level imaging is discussed.

Impurity sites are found to be responsible for residual images. Photoelectrons are …

Aerosol Particle Scavenging By Fog And Haze Droplets, Josef Podzimek

Physics Faculty Research & Creative Works

Droplet imprints in thin gelatin layers have been used for the investigation of coarse particles embedded in fog (haze) droplets in comparison to interstitial particles. Droplet samples were taken in less polluted regions of Missouri and Illinois and also in more polluted marine-urban environment in Italy. Considerable differences in particle size distribution and particle location inside the droplets have been found in samples collected on four sampling sites. The deduced relationships can be applied for the description of the aerosol scavenging process in fogs. The pollution of fog (haze) droplets may be related to the droplet mean volume radius and …

Self-Consistent Effective Binary Interaction Approximation For Strongly Coupled Multifluid Dynamics, John D. Ramshaw

Physics Faculty Publications and Presentations

An improved self-consistent effective binary diffusion approximation for multicomponent diffusion was recently described [1]. Here we develop an analogous self-consistent effective binary interaction (SCEBI) approximation for simplifying multifluid dynamical descriptions in which each fluid is strongly coupled to the other fluids by pairwise frictional forces. The net drag force on each fluid is the summation of the drag forces due to each of the other fluids. This summation is approximated by a single term proportional to the velocity of the fluid in question relative to an appropriately weighted average velocity. This approximation permits an explicit numerical solution for the fluid …

How Much Reliability And Yield Is Enough For A Ctbt?, David W. Hafemeister

Physics

No abstract provided.

Charged Particles And Neutral Kaons In Photoproduced Jets At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Charged particles (h±) and K0 mesons have been studied in photoproduced events containing at least one jet of ET > 8 GeV n a pseudorapidity interval (-0.5, 0.5) in the ZEUS laboratory frame. Distributions are presented in terms of transverse momentum, pseudorapidity and distance of the particle from the axis of a jet. The properties of h± within the jet are described well using the standard settings of PYTHIA, but the use of the multiparton interaction option improves the description outside the jets.

Factorization And Effective Action For High-Energy Scattering In Qcd, Ian Balitsky

Physics Faculty Publications

The author demonstrates that the amplitude of the high-energy scattering can be factorized in a convolution of the contributions due to fast and slow fields. The fast and slow fields interact by means of Wilson-line operators -- infinite gauge factors ordered along the straight line. The resulting factorization formula gives a starting point for a new approach to the effective action for high-energy scattering.

Ion Bernstein Waves Driven By Two Transverse Flow Layers, Mark Anthony Reynolds, G. Ganguli

Publications

The interaction between two narrow layers of E3B flow is investigated, along with their stability properties. The mode frequencies, growth rates, and eigenfunctions are calculated. It is found that the instability due to a single layer is robust to the inclusion of a second layer. Specifically, when the separation between the layers is on the order of the ion-cyclotron radius, there is strong coupling between the two layers and the second layer is destabilizing. In addition, when the flow velocities are in opposite directions a wide variety of modes is possible, including near-zero-frequency modes, resulting in broadband structure in both …

The Effect Of Temperature Dependent Frequency Factor On The Evaluated Trapping Parameters Of Tsl Glow Curves, A. N. Yazici, Z. Öztürk

Turkish Journal of Physics

The effect of temperature dependency on frequency factor and its relationship to trapping parameters is discussed by using the peak shape method. The coefficients appearing in the peak shape formula for the calculation of the activation energy have been determined and tabulated for the symmetry factor $\mu_g(X)$ for $x=0.50$ and 0.75 of the peak intensity. It is found that significant errors occur in the value of the trapping parameters if the temperature dependecy of the frequency factor is not consider.

Thermodynamics And Structure Of Simple Liquid Metals Calculated Using An Analytic Pair Potential, Serap Dalgiç, Seyfettin Dalgiç, M. Tomak

Turkish Journal of Physics

The analytic interatomic pair potential for simple metals is derived from first principles using second order pseudopotential theory by Pettifor and Ward . It is developed using the Heine-Abarenkov pseudopotential for simple metals and applied to the calculations of the structural and thermodynamic properties of liquid metals. The corresponding liquid metal structure is calculated using the random phase approximation and the hypernetted-chain formulation. The long-wavelength limit S(0) of the structure factor of liquid metals using the hard-sphere system as reference is also investigated. The calculated thermodynamic and structural properties using the real space formalism are in better agreement with experimental …

A Study On The Effect Of Ni Dopping On Bi-Pb-Sr-Ca-Cu-O System, M. Tepe, D. Abukay

Turkish Journal of Physics

The effect of $Ni$ doping on superconductivity properties of the $Bi_{1.7}Pb_{0.3}Sr_2Ca_2(Cu_{1-x}Ni_x)_3O_y$ system has been investigated by means of $x$-ray diffraction, ac electrical resistance, ac magnetic susceptibility and critical current measurements. The volume fraction of the 2223 phase decreases with increasing $Ni$ concentration. The zero-resistance temperature and the critical current density are suppressed with $Ni$ substitution.

Modelling Of Radiation Regime Receiver Cavities Of Solar Power Plants, Eduard Avanesov, Nina Berezhnaya

Turkish Journal of Physics

In this work, we develop a model for radiant heat transfer calculations inside spherical and cylindrical spaces. The analysis of the possibility of mirror cone subreflector applications for uniform flux density attainment is carried out. A procedure optimizing equiilluminate space forming a search for an indicatrix's composition is developed.

Anomalous Electrical Characteristics Of Ion Implanted P^+-N Juntions, N. Siddiqui

Turkish Journal of Physics

Electrical characteristics of three $P^+ - n$ diodes fabricated on high resistivity silicon by ion implantation technique are studied by making capacitance-voltage (C-V), reverse current-voltage (I-V) and dielectric spectroscopy of semiconductor (DSS) measurements. The C-V characteristics show abrupt fall in capacitance, while I-V characteristics show abrupt rise in current at the same voltages as in the C-V characteristics. These abrupt discontinuities are ascribed to the formation of defect clusters in the lightly doped base regions where charge transfer might be taking place by thermally assisted tunneling. Low activation energies obtained in the DSS measurements also point toward the same mechanism.

Electro-Optic Response Of A Polymer Dispersed Liquid Crystal Film, Rıdvan Karapinar

Turkish Journal of Physics

Polymer dispersed liquid crystal (PDLC) films are potentially useful in electro-optic devices since they can be used for vision products. In this work the PDLC thin films were prepared by a photopolymerization induced phase separation method and electro-optic properties of the films were investigated.

Reorientation Of Magnetization In Thin Films, Bengü Kaplan

Turkish Journal of Physics

The spin wave energy is determined by the competition between uniaxial and cubic anisotropy. We discuss the reorientation temperature $ T_{R} $ of magnetization in two-dimension and calculate its dependence on the exchange, $J$, and the uniaxial anisotropy, $G$, parameters within random phase approximation. We find that $ T_{R} $ varies as $ \sqrt{JG} $ in the planar regime.

Space Charge Limited Current In Films Obtained In Glow Discharge Plasma, M.M. Akhmedov, M.K. Kerimov, B.A. Suleimanov, S.A. Mansimov

Turkish Journal of Physics

The electrical current in thin films obtained by the polymerization of acetonitrile in glow discharge on a heated substrate were investigated in order to determine the mechanism of electrical conduction. The results of the field dependence, sample thickness dependence of the dark conductivity, supported by the results of photocurrent measurements, suggest an exponential energy distribution of traps inside the band gap of the polymer.

The Submilimeter-Wave Rotational Spectrum Of Isopropyl Alcohol, C. Qajar, S. Musaev

Turkish Journal of Physics

The submilimeter-wave spectrum of the {\em trans} isopropyl alcohol was studied in the frequency range from 240 to 480 GHz. More than 170 lines were assigned to ground state transition. The identification of the high $J$ transitions was checked by centrifugal distortion analysis. The frequencies of all transitions were least squares fitted to the Watson's Hamiltonian, including two $P^8$ terms. The ground-state rotational constants are (in MHz) A = 8489.0150, B = 8041.9182, C = 4765.2326, which yield an asymmetry parameter $\kappa = 0.75986663$.

The Eect Of Exposure Time To Clean Room Air On Characteristic Parameters Of Au /Epilayer N-Si Schottky Diodes, M. Sağlam, Ç. Nuhoğlu, E. Ayyildiz, A. Türüt, H.A. Çeti̇nkara

Turkish Journal of Physics

A study has been made on determination and comparison of current-voltage (I-V) and capacitance-voltage (C-V) characteristics parameters of $Au/n-Si$ Schottky barrier diodes (SBDs) with and without thin native oxide layer fabricated on $n$-type $Si$ grown by LPE (Liquid-phase Epitaxy) technique. The native oxide layer with different thicknesses on chemically cleaned on $Si$ surface were obtained by exposing the surfaces to clean room air before evaporating metal. The native oxide thicknesses of samples D2, D3, D4 and D5 are in the form $D2 < D3 < D4 \leq D5$, depending on the exposing time. It has been seen that the values of barrier height $\Phi_b$ of samples D2(0.64 eV), D3(0.66 eV), D4(0.69 eV) and D5(0.69 eV) with the interfacial layer increased with increasing the exposure time and tended to that of the initial sample D1 (nonoxidezed sample, 0.74 eV), and thus also their I-V and C-V curves. The reverse current of sample D1 showed slight nonsaturating behavior. This ''soft'' behavior has been ascribed to the spatial inhomogeneity in the barrier heights at the MS interface. In particular, reverse bias curves of samples D2, D3, D4 and D5 have shown excellent saturation which may be attributed to the passivation of the semiconductor surface states by the native oxide layer which reduces the penetration of the wave functions of electron in the metal into the semiconductor. Especially, the I-V characteristics and experimental parameters of our devices are in agreement with recently reported results revealed by the pulsed surface photovoltage technique for the electronic properties of the HF-treated Si surface during initial oxidation in air.