Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 9631 - 9660 of 10317

Full-Text Articles in Physical Sciences and Mathematics

Canonical Treatment Of Regular Lagrangians With Holonomic Constraints As Singular Systems, Eqab M. Rabei Jan 1999

Canonical Treatment Of Regular Lagrangians With Holonomic Constraints As Singular Systems, Eqab M. Rabei

Turkish Journal of Physics

Regular Lagrangians with holomonic constraints are treated as singular systems using the canonical method. The Lagrange multipliers are introduced as generalized coordinates. The regular Lagrangians are extended to be singular and the Hamiltonian formulation is obtained. The equations of motion are written as total differential equations in terms of the time t and the Lagrange multipliers. It is also shown that Lagrange multipliers can be determined from the integrability conditions.


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 Jan 1999

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%.


Influence Of Electrical Field On Pulsed Laser Beam Welding Of Stainless Steel (304), Salah A. H. Fawzi̇, Raz N. Ari̇f Jan 1999

Influence Of Electrical Field On Pulsed Laser Beam Welding Of Stainless Steel (304), Salah A. H. Fawzi̇, Raz N. Ari̇f

Turkish Journal of Physics

Pulsed laser beam welding experiment were carried out on stainless steel (SUS 304), using vertical and horizontal electric fields of different intensities to study its effectiveness on the welding process, regarding depth and weld quality. Pulsed Nd: YAG laser emitting 10 ms pulses in the TEM_{00} mode at 1.06 \mu m wave length was employed, microstructure of welded zone and defect were investigated using optical and scanning electron microscopes. Tensile test and microhardness measurements were carried out to evaluate the weld quality. Welding by this method increased the efficiency tremendously and a depth increase of 85% was achieved.


The Peculiarities Of The Electrical And Thermoelectrical Properties Of P-Type Ag_2te, Ali̇ İhsan Demi̇rel, S. A. Aliev, F. F. Aliev, F. Z. Guseynov, Sali̇m Orak Jan 1999

The Peculiarities Of The Electrical And Thermoelectrical Properties Of P-Type Ag_2te, Ali̇ İhsan Demi̇rel, S. A. Aliev, F. F. Aliev, F. Z. Guseynov, Sali̇m Orak

Turkish Journal of Physics

The electrical and thermoelectrical properties of p-type Ag_2Te have been investigated. Various peculiarities were observed: the minimum (at T \approx 65 K) and maximum (at T \approx 200 K) on the temperature dependence of conductivity \sigma (T); the weak dependence of Hall coefficient R(T) (in 200-300 K range) and the maximum (at T \approx 100 K and 250 K) on the temperature dependence of thermal power \alpha_0 (T). The investigation results were interpreted by two-bands model. It is shown that mentioned peculiarities have been stimulated by the narrow gap of Ag_2Te and its temperature dependence.


Q-Calculus And Irreversible Dynamics On A Hierarchical Lattice, Ayşe Erzan, Ayşe Gorbon Jan 1999

Q-Calculus And Irreversible Dynamics On A Hierarchical Lattice, Ayşe Erzan, Ayşe Gorbon

Turkish Journal of Physics

On a lattice with equal spacing on the logarithmic scale, a momentum operator that respects the asymmetry of this nonlinear lattice yields a kinetics that can be understood in terms of diffusion on an underlying ultrametric space, if one also identifies the cannonical commutator with the time dilation operator. The motion to which this non-conventional kinetics corresponds is irreversible, with an explicit violation of time reversal symmetry resulting from the spreading with time of a probability distribution over a larger and larger volume of the phase space.


Dynamical Evolution Of The Rs Cvn-Type Binaries, Osman Demi̇rcan Jan 1999

Dynamical Evolution Of The Rs Cvn-Type Binaries, Osman Demi̇rcan

Turkish Journal of Physics

The orbital angular momentum (orbital AM) of a sample of forty RS CVn-type binaries with the orbital periods P \leq 10 days were estimated and the orbital AM distribution with respect to P was critically interpreted as the orbital AM evolution of these systems caused by the magnetic breaking process with the existence of spin-orbit coupling. The empirical relations (between the orbital AM loss, mass loss and period variation) derived from the diagram of the orbital AM distribution were used in deriving a semi-empirical formula for the dynamical evolution of the RS CVn-type binaries. The magnetic breaking induced dynamical evolution …


Fundamental Research And Device Technology, B. K. Ridley Jan 1999

Fundamental Research And Device Technology, B. K. Ridley

Turkish Journal of Physics

Highlights of the interaction between fundamental research and semiconductor device technology are summarized.


Coherent Control Experiments As A Probe Of The Carrier Scattering Processes, P. Le Jeune, X. Marie, T. Amand, M. Paillard, J. Barrau Jan 1999

Coherent Control Experiments As A Probe Of The Carrier Scattering Processes, P. Le Jeune, X. Marie, T. Amand, M. Paillard, J. Barrau

Turkish Journal of Physics

We report on coherent control experiments of excitons in GaAs/AlGaAs Quantum wells.This technique, which relies on the linear response of the crystal,is used to investigate the spin-dependent exciton-exciton scattering.


Semiconductor And Dielectric Microcavity Spectroscopy, Ali̇ Serpengüzel Jan 1999

Semiconductor And Dielectric Microcavity Spectroscopy, Ali̇ Serpengüzel

Turkish Journal of Physics

Semiconductor and dielectric microcavities are used for the localization of photons as well as the enhancement of photon density of states. The enhancement of photoluminescence, electroluminescence, and lasing by the use of microcavities leads to novel active and passive optoelectronic and photonic devices such as channel droppping filters, semiconductor lasers, and resonant cavity enhanced devices. Experimental results showing photoluminescence enhancement in active planar, lasing in active ellipsoidal microcavities as well as light scattering in passive and spherical microcavities are presented.


A New Approach To Immersion Theory, Colin Rourke, Brian Sanderson Jan 1999

A New Approach To Immersion Theory, Colin Rourke, Brian Sanderson

Turkish Journal of Mathematics

No abstract provided.


Structure Of M-Dimensional Implicitly Defined Surfaces In N-Dimensional Euclidean Space E_N, Alla Borisovna Kotlyar Jan 1999

Structure Of M-Dimensional Implicitly Defined Surfaces In N-Dimensional Euclidean Space E_N, Alla Borisovna Kotlyar

Turkish Journal of Mathematics

We consider the structure of the surface in the given point, if we vary all its normals in this point.


Modular Symmetry Classes Of Tensors, M. Shahryari, M. A. Shahabi Jan 1999

Modular Symmetry Classes Of Tensors, M. Shahryari, M. A. Shahabi

Turkish Journal of Mathematics

We introduce the notion of modular symmetry classes of tensors and give a necessary and sufficient condition for a modular symmetry class of tensors associated with the full symmetric group to be non-zero. Then we use modular symmetry classes of tensors to study the polynomial representations of $GL(V)$, where $V$ is a vector space over a field of characterisitic $p$. At the end we introduce a non-degenerate bilinear form on a modular symmetry class. Some problems are also given.


The Structure Of A Solvmanifold's Heegaard Splittings, Darly Cooper, Martin Scharlemann Jan 1999

The Structure Of A Solvmanifold's Heegaard Splittings, Darly Cooper, Martin Scharlemann

Turkish Journal of Mathematics

No abstract provided.


Planar Linkages And Algebraic Sets, Henry C. King Jan 1999

Planar Linkages And Algebraic Sets, Henry C. King

Turkish Journal of Mathematics

No abstract provided.


A Program To Search For Homotopy 3-Spheres, Michael Greene, Colin Rouke Jan 1999

A Program To Search For Homotopy 3-Spheres, Michael Greene, Colin Rouke

Turkish Journal of Mathematics

No abstract provided.


Simply Connected Symplectic 4-Manifolds Withpositive Signature, Andras I. Stipsicz Jan 1999

Simply Connected Symplectic 4-Manifolds Withpositive Signature, Andras I. Stipsicz

Turkish Journal of Mathematics

No abstract provided.


Left Adjoint Of Pullback Cat^1 -Groups, Murat Alp Jan 1999

Left Adjoint Of Pullback Cat^1 -Groups, Murat Alp

Turkish Journal of Mathematics

In [1] we define the pullback Cat^1-groups and showed that the category of pullback Cat^1-groups is equivalent to the category of pullback crossed modules. In this paper we proved that the pullback Cat^1-group has a left adjoint which is the induced Cat^1-group. We also give the left adjoint construction.


Normal Subgroups And Elements Of H^{'}(\Lambda_Q), İsmai̇l Naci̇ Cangül Jan 1999

Normal Subgroups And Elements Of H^{'}(\Lambda_Q), İsmai̇l Naci̇ Cangül

Turkish Journal of Mathematics

In this study, we consider the normal subgroups of H^{'}(\lambda_q), where H(\lambda_q) denotes the Hecke groups. After recalling some results from [2], particularly on the group structure and on the relations with the power subgroups of H(\lambda_q), the even subgroup H_e(\lambda_q) of H(\lambda_q) is discussed. It is shown that H^{'}(\lambda_q) is a normal subgroup of H_e(\lambda_q) with index q. For this reason each subgroup of H^{'}(\lambda_q) consists of only even elements. H^{''}(\lambda_q) is also considered and it is concluded that it is the normal subgroup of H^{'}(\lambda_q) generated by all commutators of the elements of H^{'}(\lambda_q). Using the Kurosh subgroup …


On The Boundedness Of Integral Operators, İsmai̇l Eki̇nci̇oğlu, Isroil A. Ikromov Jan 1999

On The Boundedness Of Integral Operators, İsmai̇l Eki̇nci̇oğlu, Isroil A. Ikromov

Turkish Journal of Mathematics

In this paper, we consider integal operators defined by kernel functions. It is well known the boundedness of such kind of operators as Shur Lemma type statements. But, the norm of operators was estimated by two integrals of kernel function. We obtain estimation of operators norm by one integral of kernel function.


Some Asymptotic Estimates For The Instability Intervals Of Hill's Equation, Haskiz Coşkun Jan 1999

Some Asymptotic Estimates For The Instability Intervals Of Hill's Equation, Haskiz Coşkun

Turkish Journal of Mathematics

In this study, some asymptotic estimates for the length of the instability intervals of Hill's equation, y''(t)+(\lambda -q(t))y(t)=0, are derived by means of an auxiliary eigenvalue problem under various assumptions on the Fourier coefficients of the potential q.


Geodesics In A Tensor Bundle, Abdullah Kopuzlu, Ari̇f A. Salimov Jan 1999

Geodesics In A Tensor Bundle, Abdullah Kopuzlu, Ari̇f A. Salimov

Turkish Journal of Mathematics

The main purpose of the present paper is to study geodesics in a tensor bundle T^{p}_q(M_n) with respect to the horizontal lift ^H\nabla of an affine connection \nabla .


Criteria Of Le Page Type In Involutive Banach Algebras, Abdellah El Kinani, Mohamed Oudadess Jan 1999

Criteria Of Le Page Type In Involutive Banach Algebras, Abdellah El Kinani, Mohamed Oudadess

Turkish Journal of Mathematics

The Le Page inequality in Banach algebras is \parallel xy \parallel\leq\alpha\parallel yx\parallel. We consider inequalities where a linear involution appears and has consequences on the involution itself and commutativity results.^1


Segal Algebra As An Ideal In Its Second Dual Space, Heybet S. Mustafayev Jan 1999

Segal Algebra As An Ideal In Its Second Dual Space, Heybet S. Mustafayev

Turkish Journal of Mathematics

For a locally compact group G, let S(G) be a symmetric Segal algebra. We prove that S(G) is an ideal in its second dual space if and only if G is compact, where the second dual is equipped with an Arens multiplication.


Some Results On Space-Like Line Congruences And Their Space-Like Parameter Ruled Surface, E. Özyilmaz Jan 1999

Some Results On Space-Like Line Congruences And Their Space-Like Parameter Ruled Surface, E. Özyilmaz

Turkish Journal of Mathematics

Using dual vectors, space-like ruled surfaces was introduced in [2]. In this paper, we define space-like line congruence and their space-like parameter ruled surfaces {\mathbf R_{11}(t)} and {\mathbf R_{21}(t)} of R_1^3. Then, by choosing space-like parameter ruled surfaces as space-like principle ruled surfaces, we obtain some relations among the magnitudes of space-like ruled surfaces {\mathbf R_1(t)}, {\mathbf R_{11}(t)}.


Cycloidal Normal Subgroups Of Hecke Groups Of Finite Index, İsmai̇l Naci̇ Cangül, Osman Bi̇zi̇m Jan 1999

Cycloidal Normal Subgroups Of Hecke Groups Of Finite Index, İsmai̇l Naci̇ Cangül, Osman Bi̇zi̇m

Turkish Journal of Mathematics

Cycloidal normal subgroups, that is, subgroups with only one cusp, of finite index of Hecke groups, which have been introduced by E. Hecke, and can be thought of as some kind of generalisation of the well-known modular group, are studied. It is shown that they correspond to cyclic quotients of Hecke groups and therefore have non-compact associated Riemann surfaces with a cusp. Finally, their total number have been formulated.


Generalized Solutions Of A Class Of Linear And Quasi-Linear Degenerated Hyperbolic Equations, Rossitza Semerdjieva Jan 1999

Generalized Solutions Of A Class Of Linear And Quasi-Linear Degenerated Hyperbolic Equations, Rossitza Semerdjieva

Turkish Journal of Mathematics

The equation $L(u):=k(y)u_{xx}-\partial_y(\ell(y)u_y)+r(x,y)u=f(x,y,u),$ where $k(y)>0, \ell(y)>0$ for $y>0,k(0)=\ell(0)=0$ and $lim_{y\rightarrow 0}k(y)/\ell(y)$ exists, is strictly hyperbolic for $y>0$ and its order degenerates on the line $y=0$. We consider the boundary value problem $Lu=f(x,y,u)$ in $G, u\mid_{AC}=0$, where $G$ is a simply connected domain in $R^2$ with piecewise smooth boundary $\partial G=AB\cup AC\cup BC; AB=\{(x,0): 0\leq x\leq 1\}, AC : x=F(y) =\int_0^y(k(t)/\ell (t))^{1/2}dt$ and $BC: x=1-F(y)$ are characteristic curves. The existence and uniqueness of a generalized solution to this problem are proved in the linear case (where $f=f(x,y));$ the nonlinear case is treated by using the Schauder Fixed …


Alternative Polynomial And Holomorphic Dunford-Pettis Properties, Walden Freedman Jan 1999

Alternative Polynomial And Holomorphic Dunford-Pettis Properties, Walden Freedman

Turkish Journal of Mathematics

Alternatives to the Polynomial Dunford-Pettis property and the Holomorphic Dunford-Pettis property, called the PDP1 and HDP1 properties, respectively, are introduced. These are shown to be equivalent to the DP1 property, an alternative Dunford-Pettis property previously introduced by the author, thus mirroring the equivalence of the three original properties.


A Class Of Banach Algebras Whose Duals Have The Schur Property, H. Mustafayev, A. Ülger Jan 1999

A Class Of Banach Algebras Whose Duals Have The Schur Property, H. Mustafayev, A. Ülger

Turkish Journal of Mathematics

Call a commutative Banach algebra $A$ a $\gamma$-algebra if it contains a bounded group $\Gamma$ such that $\overline{aco(\Gamma)}$ contains a multiple of the unit ball of $A$. In this paper, first by exhibiting several concrete examples, we show that the class of $\gamma$-algebras is quite rich. Then, for a $\gamma$-algebra $A$, we prove that $A^{\star}$ has the Schur property iff the Gelfand spectrum $\sum$ of $A$ is scattered iff $A^{\star}=ap(A)$ iff $A^{\star}=\overline{Span(\sum)}$.


Some Theorems Involving Inequalities On P-Valent Functions, Hüseyi̇n Irmak, Ömer Faruk Çeti̇n Jan 1999

Some Theorems Involving Inequalities On P-Valent Functions, Hüseyi̇n Irmak, Ömer Faruk Çeti̇n

Turkish Journal of Mathematics

In this paper, some theorems involving inequalities on $p$-valent functions (that is $p$-valenty close-to-convex functions, $p$-valently starlike functions, and $p$-valently convex functions) are given. Moreover, some applications in the theorems which are important for geometric function theory are also included. Keywords: Analytic, $p$-valent, $p$-valently colse-to-convex functions, $p$-valently starlike functions, $p$-valently convex functions, open unit disk, and Jack's Lemma.


Masatoshi Gündüz İkeda, Mehpare Bi̇lhan Jan 1999

Masatoshi Gündüz İkeda, Mehpare Bi̇lhan

Turkish Journal of Mathematics

No abstract provided.