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Articles 8791 - 8820 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Abelian Fibred Holomorphic Symplectic Manifolds, Justin Sawon
Abelian Fibred Holomorphic Symplectic Manifolds, Justin Sawon
Turkish Journal of Mathematics
We study holomorphic symplectic manifolds which are fibred by abelian varieties. This structure is a higher dimensional analogue of an elliptic fibration on a K3 surface. We investigate when a holomorphic symplectic manifold is fibred in this way, and are led to several natural conjectures. We then study the geometry of these fibrations. The expectation is that this point of view will prove useful in understanding holomorphic symplectic manifolds, and possibly lead to a classification.
Symplectic Surgeries From Singularities, Ivan Smith, Richard Thomas
Symplectic Surgeries From Singularities, Ivan Smith, Richard Thomas
Turkish Journal of Mathematics
We describe a variety of symplectic surgeries (not a priori compatible with Kaehler structures) which are obtained by combining local Kaehler degenerations and resolutions of singularities. The effect of the surgeries is to replace configurations of Lagrangian spheres with symplectic submanifolds. We discuss several examples in detail, relating them to existence questions for symplectic manifolds with c_1 > 0, c_1 = 0, c_1 < 0 in four and six dimensions.
Some Asymptotic Results For The Semi-Markovian Random Walk With A Special Barrier, Tahi̇r Khani̇yev
Some Asymptotic Results For The Semi-Markovian Random Walk With A Special Barrier, Tahi̇r Khani̇yev
Turkish Journal of Mathematics
In this study, the semi-Markovian random walk with a special barrier (X(t)) is considered and under some weak assumptions the ergodicity of this process is discussed. Moreover, the characteristic function of ergodic distribution of X(t) is given by using a joint distribution of random variables N and Y_{N} and some exact formulas for the first and second moments of ergodic distribution of the process X(t) are obtained. Based on these results, the asymptotic behaviours of expectation and variance of this process are investigated as S-s \to \infty . It is finally proved that the ergodic distribution of the process is …
Boundary Points Of Self-Affine Sets In R, İbrahi̇m Kirat
Boundary Points Of Self-Affine Sets In R, İbrahi̇m Kirat
Turkish Journal of Mathematics
Let A be an n \times n expanding matrix with integer entries and D = \{0, d_1, ... , d_{N-1} \} \subseteq {\Bbb{Z}}^n be a set of N distinct vectors, called an N-digit set. The unique non-empty compact set T = T(A,D) satisfying AT = T + D is called a self-affine set. If T has positive Lebesgue measure, it is called a self-affine region. In general, it is not clear how to determine a point to be on the boundary of a self-affine region. In this note, we consider one-dimensional self-affine regions T and present a simple approach to …
On Lightlike Hypersurfaces Of A Semi-Riemannian Space Form, Rifat Güneş, Bayram Şahi̇n, Erol Kiliç
On Lightlike Hypersurfaces Of A Semi-Riemannian Space Form, Rifat Güneş, Bayram Şahi̇n, Erol Kiliç
Turkish Journal of Mathematics
In this paper, we study a Lightlike hypersurface of a semi-Riemann manifold. We show that a lightlike hypersurface is totally geodesic if and only if it is locally symmetric. Also, we show that a lightlike Hypersurface of IR_{4q}^{4m}(m,q > 1) is totally geodesic under some restrictions. Finally, we give some results on Ricci curvature of a lightlike hypersurface to be symmetric.
On Pseudohyperbolical Curves In Minkowski Space-Time, Çeti̇n Camci, Kazim İlarslan, Emilija Sucurovic
On Pseudohyperbolical Curves In Minkowski Space-Time, Çeti̇n Camci, Kazim İlarslan, Emilija Sucurovic
Turkish Journal of Mathematics
In this paper, we characterize all spacelike, timelike and null curves lying on the pseudohyperbolic space H_0^3 in the Minkowski space--time E_1^4. Moreover, we prove that there are no timelike and no null curves lying on the pseudohyperbolic space H_0^3 in Minkowski space--time E_1^4.
On Prime Submodules Of Finitely Generated Free Modules, Di̇lek Pusat Yilmaz
On Prime Submodules Of Finitely Generated Free Modules, Di̇lek Pusat Yilmaz
Turkish Journal of Mathematics
The aim of this work is to investigate prime submodules of finitely generated free modules over commutative domains in some special cases.
Groups Whose Proper Subgroups Are Hypercentral Of Length At Most \Leq \Omega, Selami̇ Ercan
Groups Whose Proper Subgroups Are Hypercentral Of Length At Most \Leq \Omega, Selami̇ Ercan
Turkish Journal of Mathematics
Groups, all proper subgroups of which are hypercentral of length at most \omega and every proper subgroup of which is a B_{n}-group for a natural number n depending on the subgroup, are studied in this article.
Automorphism Groups Of (M-1)-Surfaces With The M-Property, Adnan Melekoğlu
Automorphism Groups Of (M-1)-Surfaces With The M-Property, Adnan Melekoğlu
Turkish Journal of Mathematics
A compact Riemann surface X of genus g is called an (M-1)-surface if it admits an anticonformal involution that fixes g simple closed curves, the second maximum number by Harnack's theorem. If X also admits an automorphism of order g which cyclically permutes these g curves, then we shall call X an (M-1)-surface with the M-property. In this paper we investigate the automorphism groups of (M-1)-surfaces with the M-property.
Fuzzy Ideals In Gamma-Rings, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun
Fuzzy Ideals In Gamma-Rings, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun
Turkish Journal of Mathematics
The converse of [7, Theorem 3.3] is provided. For an Artinian \Gamma-ring, a few results are investigated.
On The Weak-Integrity Of Trees, Alpay Kirlangiç
On The Weak-Integrity Of Trees, Alpay Kirlangiç
Turkish Journal of Mathematics
In this paper the concept of {\em weak-integrity} is introduced as a new measure of the stability of a graph \( G \) and it is defined as I_{w}(G)={\min_{S\subset V(G)}\{ S +m_{e}(G-S)\}}, where m_{e}(G-S) denotes the number of edges of a largest component of G-S. We investigate the weak-integrity of trees and compute the weak-integrity of a binomial tree and all the trees with at most 7 vertices. We also give some results about the weak-integrity of graphs obtained from binary operations.
On Invariant Submanifolds Of Riemannian Warped Product Manifold, Mehmet Atçeken, Bayram Şahi̇n, Erol Kiliç
On Invariant Submanifolds Of Riemannian Warped Product Manifold, Mehmet Atçeken, Bayram Şahi̇n, Erol Kiliç
Turkish Journal of Mathematics
In this paper, we generalize the geometry of the invariant submanifolds of Riemannian product manifold to the geometry of the invariant submanifolds of Riemannian warped product manifold. We investigate some properties of an invariant submanifolds of a Riemannian warped product manifold. We show that every invariant submanifold of the Riemannian warped product manifold is a Riemannian warped product manifold. Also, we give a theorem on the pseudo-umbilical invariant submanifold. Further, we obtain that integral manifolds on an invariant submanifold are curvature-invariant submanifolds. Finally, we give a necessary condititon on a totally umbilical invariant submanifold to be totally geodesic.
Uniqueness Of Primary Decompositions, Patrick F. Smith
Uniqueness Of Primary Decompositions, Patrick F. Smith
Turkish Journal of Mathematics
Uniqueness properties of primary decompositions in modules over non-commutative rings are presented.
On Intuitionistic Fuzzy Subhypernear-Rings Of Hypernear-Rings, Kyung Ho Kim
On Intuitionistic Fuzzy Subhypernear-Rings Of Hypernear-Rings, Kyung Ho Kim
Turkish Journal of Mathematics
In this paper, we introduce the concept of an intuitionistic fuzzy subhypernear-ring of a hypernear-ring and obtain some results in this connection.
Professor Masatoshi Gündüz Ikeda: A Life Devoted To Mathematics, Cemal Koç
Professor Masatoshi Gündüz Ikeda: A Life Devoted To Mathematics, Cemal Koç
Turkish Journal of Mathematics
No abstract provided.
On The Extended Hecke Groups \Overline{H}(\Lambda _Q), Ni̇hal Yilmaz Özgür, Recep Şahi̇n
On The Extended Hecke Groups \Overline{H}(\Lambda _Q), Ni̇hal Yilmaz Özgür, Recep Şahi̇n
Turkish Journal of Mathematics
Hecke groups H(\lambda _q) have been studied extensively for many aspects in the literature, [5], [8]. The Hecke group H(\lambda_3), the modular group PSL(2, \Bbb{Z} ) , has especially been of great interest in many fields of mathematics, for example number theory, automorphic function theory and group theory. In this paper we consider the extended Hecke groups \overline{H}(\lambda _q) which are defined analogously with the extended modular group. We find the conjugacy classes of torsion elements in \overline{H}(\lambda _q). Using this we give some results about the normal subgroups and Fuchsian subgroups of \overline{H}(\lambda _q).
On Positive Solutions Of Boundary Value Problems For Nonlinear Second Order Difference Equations, Nüket Aykut, Gusein Sh. Guseinov
On Positive Solutions Of Boundary Value Problems For Nonlinear Second Order Difference Equations, Nüket Aykut, Gusein Sh. Guseinov
Turkish Journal of Mathematics
In this paper we study nonlinear second order difference equations subject to separated linear boundary conditions. Sign properties of the associated Green's functions are investigated and existence results for positive solutions of the nonlinear boundary value problem are established. Upper and lower bounds for these positive solutions also are given.
On General Fibonacci Sequences In Groups, Engi̇n Özkan
On General Fibonacci Sequences In Groups, Engi̇n Özkan
Turkish Journal of Mathematics
In this paper, we have constituted 3-step general Fibonacci sequences in a nilpotent group with exponent p (p is a prime number) and nilpotency class 4 and given formulas to find the \alpha term of the sequence.
Rough Oscillatory Singular Integral Operators-Ii, Ahmad Al-Salman, Ali A. Al-Jarrah
Rough Oscillatory Singular Integral Operators-Ii, Ahmad Al-Salman, Ali A. Al-Jarrah
Turkish Journal of Mathematics
In this paper, we study certain classes of oscillatory singular integral operators with kernels in Llog L(S^{n-1}) which is known to be the most desirable size condition for the L^{p} boundedness to hold. We prove that such operators are bounded on L^{p}. Our results extend and improve previously known results. Variations of our approach in this paper can be applied to handle more general oscillatory singular integral operators. This concludes by indicating a variety of results that can be obtained.
Music, Cbf And Differential Algebraic Constant Modulus Algorithms For Direction Of Arrival Estimation In Passive Coherent Locators, Ahmet Özçeti̇n
Music, Cbf And Differential Algebraic Constant Modulus Algorithms For Direction Of Arrival Estimation In Passive Coherent Locators, Ahmet Özçeti̇n
Turkish Journal of Electrical Engineering and Computer Sciences
In passive coherent locators (PCL) systems, noise and the precision of direction of arrival (DOA) estimation are key issues. This paper addresses the implementation of high-resolution DOA estimation methods, in particular the multiple signal classification (MUSIC) algorithm, the conventional beam forming (CBF) algorithm, and the algebraic constant modulus algorithm (ACMA). The goal is to compare the ACMA to the MUSIC and CBF algorithms for application to PCL. The results and analysis presented here support the use of constant modulus information, where available, as an important addition to DOA estimation. The ACMA offers many simple solutions to noise and separation related …
A Full Adaptive Observer For Dc Servo Motors, Ata Sevi̇nç
A Full Adaptive Observer For Dc Servo Motors, Ata Sevi̇nç
Turkish Journal of Electrical Engineering and Computer Sciences
An adaptive observer estimating all parameters and load torque is proposed for DC servo motors. The observer uses no direct feedback but the adaptation schemes use current and speed measurements. Both the observer and adaptations are simple to implement for real-time applications. Simulation results are satisfactory for the full adaptive observer. If the observer works in parallel with only load torque and armature resistance adaptations, the results are very good even if very low-quality sensors are used. In this simulation, only a single hall sensor is used as a rotational transducer, which produces a single pulse per revolution, and very …
New Infratechnologies In The Deregulated Power Sector, Jordan Shikoski, Vladimir Katic, Risto Rechkoski
New Infratechnologies In The Deregulated Power Sector, Jordan Shikoski, Vladimir Katic, Risto Rechkoski
Turkish Journal of Electrical Engineering and Computer Sciences
This paper discusses new infratechnologies in the deregulated power sector. Most measurement and standardization techniques can be viewed as infratechnology. Infratechnologies are technical tools, including the measurement of data, test methods, and practices and technique. Standardization requirements are related to the measurement requirement. Although the system operation and market transactions concern many import aspects, they are insupportable and often complementary. This distinction between the technical and market information is important because the characteristics of information needs and the impact on economic efficiency and clean power are generally different. The present paper focuses on infratechnologies that can potentially increase the benefits …
Initiatory Electrons In Compressed Gases In Positive Polarity, Mohammed Messaad, Mustapha Tioursi
Initiatory Electrons In Compressed Gases In Positive Polarity, Mohammed Messaad, Mustapha Tioursi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper deals with the nature of seed electron sources in compressed N_2 for positive polarity. We present an experimental procedure that provides evidence of the fact that collisional detachment from negative ions plays the most important role in the supply of seed electrons. Conditioning phenomena in compressed SF_6, N_2 and air have been simulated under positive lightning impulses for point-plane geometry.
Polyethyleneimine-Coated Capillaries For The Separation Of Dna By Capillary Electrophoresis, M. Sai̇d Nutku, F. Bedi̇a Eri̇m Berker
Polyethyleneimine-Coated Capillaries For The Separation Of Dna By Capillary Electrophoresis, M. Sai̇d Nutku, F. Bedi̇a Eri̇m Berker
Turkish Journal of Chemistry
A new capillary electrophoresis of DNA fragments has been achieved with the cooperative effects of the electrophoretic and electroosmotic mobilities realized via the polyethyleneimine (PEI) coating of the capillary walls. As a result, seven of the 11 different-sized DNA fragments have produced resolved CE peaks. Our results demonstrate that analyses of DNA constituents can be performed under a wide range of conditions by the appropriate tuning of the coating and filler within the capillary.
Search For A Nonelectrocyclic Cyclization Of Nitrosostyrene: Rearrangements Of Michael Adducts From Dmad And \Alpha-Dialkylamino Oximes, Necdet Coşkun, Nevi̇n Arikan
Search For A Nonelectrocyclic Cyclization Of Nitrosostyrene: Rearrangements Of Michael Adducts From Dmad And \Alpha-Dialkylamino Oximes, Necdet Coşkun, Nevi̇n Arikan
Turkish Journal of Chemistry
The aza-Claisen rearrangement product of the Michael adducts 2 from \alpha-dialkylaminoacetophenone oximes and DMAD underwent fragmentation to give dialkylaminomaleate, and benzonitrile at reflux in acetonitrile. The fragmentation was assumed to proceed through an unstable 4H-1,2-oxazete 6. The same reaction performed at room temperature, in addition to the nitrile and maleate, gave the corresponding 2-(2-dialkylamino-1-phenylethylideneaminooxy)-but-2- enedioic acid dimethyl esters 8 and 9. Compounds 9 isomerized to 8 on heating in acetonitrile.
Changes In Chlorophyll-Carotenoid Contents, Antioxidant Enzyme Activities And Lipid Peroxidation Levels In Zn-Stressed Mentha Pulegium, Ni̇lgün Candan, Leman Tarhan
Changes In Chlorophyll-Carotenoid Contents, Antioxidant Enzyme Activities And Lipid Peroxidation Levels In Zn-Stressed Mentha Pulegium, Ni̇lgün Candan, Leman Tarhan
Turkish Journal of Chemistry
The relationships between chlorophyll-carotenoid contents, the antioxidant enzyme activities, such as superoxide dismutase (SOD), catalase (CAT), ascorbate-dependent peroxidase (AsA-dep POD) and guaiacol-dependent peroxidase (Gua-dep POD), and lipid peroxidation (LPO) levels were investigated in leaves at different positions of M. pulegium grown in nutrient medium containing 0-1 \mu M Zn. The maximum chlorophyll-carotenoid content's SOD and CAT activities and the minimum LPO level were observed in leaf 6 at 7.6 10^{-2} \mu M Zn (as control). While chlorophyll-carotenoid contents in the absence of Zn were lower than those of the control, SOD and CAT activities significantly increased with decreasing Zn concentration. …
An Efficient Synthesis Of Alnustone, A Naturally Occurring Compound, Süleyman Göksu, Hülya Çeli̇k, Hasan Seçen
An Efficient Synthesis Of Alnustone, A Naturally Occurring Compound, Süleyman Göksu, Hülya Çeli̇k, Hasan Seçen
Turkish Journal of Chemistry
Alnustone, 4(E),6(E)-1,7-diphenyl-hepta-4,6-dien-3-one, was synthesized starting from benzaldehyde in three steps with an overall yield of 57%. The condensation of benzaldehyde with acetone gave benzalacetone. The Pd-C catalyzed hydrogenation of benzalacetone afforded benzylacetone. The in situ enamination of benzylacetone with pyrrolidine and acetic acid followed by cinnamaldehyde treatment gave alnustone.
Synthesis Of Some New Benzimidazole Carbamate Derivatives For Evaluation Of Antifungal Activity, Canan Kuş, Nurten Altanlar
Synthesis Of Some New Benzimidazole Carbamate Derivatives For Evaluation Of Antifungal Activity, Canan Kuş, Nurten Altanlar
Turkish Journal of Chemistry
The synthesis and structure elucidation of methyl 5(6)-fluoro-6(5)-substituted-1H-benzimidazole carbamate derivatives are performed and their antifungal activities evaluated against Candida albicans.
Chromatographic Determination Of Phenolic Acids In The Snowdrop By Hplc, Mustafa Tüzen, Mustafa Özdemi̇r
Chromatographic Determination Of Phenolic Acids In The Snowdrop By Hplc, Mustafa Tüzen, Mustafa Özdemi̇r
Turkish Journal of Chemistry
Free and esterified phenolic acids of Galanthus elwesii (snowdrop) were extracted with petroleum ether and determined by HPLC. Cinnamic, ferulic, vanillic, p-coumaric, p-hydroxy benzoic, and caffeic acids were detected by a linear gradient elution with acetic acid/water (2:98 v/v) and acetic acid/acetonitrile/water (2:30:68 v/v) as the mobile phases in 30 min with a flow rate of 1.5 mL/min. Among the acids from snowdrop extracts, p-hydroxy benzoic was the major constituent followed by vanillic and ferulic acids.
Thermal Decomposition Kinetics Of Anilino-P-Chlorophenylglyoxime Complexes Of Cobalt (Ii), Nickel (Ii) And Copper (Ii), Hakan Arslan, Nevzat Külcü, Ali̇ İhsan Pekacar
Thermal Decomposition Kinetics Of Anilino-P-Chlorophenylglyoxime Complexes Of Cobalt (Ii), Nickel (Ii) And Copper (Ii), Hakan Arslan, Nevzat Külcü, Ali̇ İhsan Pekacar
Turkish Journal of Chemistry
The Co(II), Ni(II) and Cu(II) complexes of anilino-p-chlorophenylglyoxime were synthesised. The thermal behaviour of all complexes was studied by DTA and TG. It was found that pyrolytic decomposition occurs with melting in metal complexes and that metal oxides remain as final products of the metal complexes. A GC-MS combined system was used to identify the products during pyrolytic decomposition. The pyrolytic end products were identified by x-ray powder diffraction. The orders, n, the activation energies, E^*, the pre-exponential factors, A, and the entropies, \Delta S^*, of thermal decomposition reactions were derived from thermogravimetric and differential thermogravimetric curves. The kinetic analysis …