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Articles 10051 - 10080 of 10317
Full-Text Articles in Physical Sciences and Mathematics
Poly(3-Alkylthiophene) Modifications, A. Bolognesi
Poly(3-Alkylthiophene) Modifications, A. Bolognesi
Turkish Journal of Chemistry
No abstract provided.
Some Recursive Relationships Between Acenes And Cyclacenes, Lemi Türker
Some Recursive Relationships Between Acenes And Cyclacenes, Lemi Türker
Turkish Journal of Chemistry
Some structural relationships between acenes and cyclacenes both H\\"{u}ckel- and Mobius-type and within the same class of compounds were demonstrated by the recursive analysis of their $E_{\pi}$ and $I_{\pi}$ values or the first differences thereof. It was found that the first differences of $E_{\pi}$ and $I_{\pi}$ tend to have certain limit values as the number of benzenoid rings increases in each class of compounds studied.
The Removal Of Organic Sulfur From Two Turkish Lignites By Chlorinolysis, Yücel Y. Kadioğlu, Semra Karaca, Samih Bayrakçeken, M. Şahin Gülaboğlu
The Removal Of Organic Sulfur From Two Turkish Lignites By Chlorinolysis, Yücel Y. Kadioğlu, Semra Karaca, Samih Bayrakçeken, M. Şahin Gülaboğlu
Turkish Journal of Chemistry
The removal of organic sulfur from two Turkish lignites by chlorinolysis with chlorine gas in water and water-carbon tetrachloride media at ambient pressure was examined. The effects of stirring speed (5-20 s^{-1}), particle size (250-425, 150-180 and 74-88 \mu m), temperature (13-70°C) and time (0-10800 s) were investigated. Significant portions of the organic sulfur in the coal samples were removed.
Reaction Of 3,4-Diformyl-2,5-Dimethylpyrrole With 1,2(Substituted)Diphenyl-1,2-Diaminoethanes, Cemil Öğreti̇r, Fatma Severcan
Reaction Of 3,4-Diformyl-2,5-Dimethylpyrrole With 1,2(Substituted)Diphenyl-1,2-Diaminoethanes, Cemil Öğreti̇r, Fatma Severcan
Turkish Journal of Chemistry
3,4-Diformyl-2,5-dimethylpyrrole (1) reacts with 1,2-diphenyl-1,2-diamine derivatives to form the potentially tautomeric 2:2 macrocyclic adduct (1)=(1). ^1H and ^{13}C n.m.r. spectral data along with acidity measurements indicate that the 2-azafulvene structure (7) is predominant for all adducts.
Potentiometric Titrations Of Semicarbazone Derivatives 6-Keto 9-17 Mono Methyl Substituted Octadecanoic Acids In Non-Aqueous Media, Mustafa Yalçin, Süleyman Tanyolaç, İrfan Kizilcikli, Aydın Tavman
Potentiometric Titrations Of Semicarbazone Derivatives 6-Keto 9-17 Mono Methyl Substituted Octadecanoic Acids In Non-Aqueous Media, Mustafa Yalçin, Süleyman Tanyolaç, İrfan Kizilcikli, Aydın Tavman
Turkish Journal of Chemistry
The pK$_a$ values of 6-semicarbazone 9-17 monomethyl substituted octadecanoic acids were determined using the potentiometric titration method. 2-Propanol was used as the non-aqueous medium and tetrabutylammonium hydroxide (TBAH) as the titrant in the experiments. The contribution of semicarbazone and methyl groups to the pK$_a$ values of octadecanoic acids was investigated and evaluated. In addition, observations were made on the IR spectra of the compounds.
Voltammetric Determination Of Salbutamol Based On Electrochemical Oxidation At Platinum And Glassy Carbon Electrodes, Niyazi Yilmaz, Sibel A. Özkan, Bengi Uslu, Zühre Şentürk, İnci Bi̇ryol
Voltammetric Determination Of Salbutamol Based On Electrochemical Oxidation At Platinum And Glassy Carbon Electrodes, Niyazi Yilmaz, Sibel A. Özkan, Bengi Uslu, Zühre Şentürk, İnci Bi̇ryol
Turkish Journal of Chemistry
The oxidative behavior of salbutamol was studied as a function of pH at platinum and activated glassy carbon electrodes. Between pH 1.9 and 12.0, the drug was characterized by a single oxidation step at both electrodes. The process was found to be dependent on the nature and the pH of the supporting elctrolyte. The procedure yielded a linear concentration range of $1 \times 10^{-4}$ to $1 \times 10^{-3}$ M and $2 \times 10^{-5}$ to $1 \times 10^{-3}$ M in 0.2 M sulphuric acid and a phosphate buffer of pH 6, at platinum and glassy carbon electrodes, respectively. The method was …
Synthesis And Characterization Of Amorphous-Liquid Crystalline Poly(Vinyl Ether) Block Copolymers, İ. Ersin Serhatli, Müge Serhatli
Synthesis And Characterization Of Amorphous-Liquid Crystalline Poly(Vinyl Ether) Block Copolymers, İ. Ersin Serhatli, Müge Serhatli
Turkish Journal of Chemistry
A new series of amorphous-liquid crystalline poly(vinyl ether) block copolymers was synthesized using living cationic polymerization and free-radical polymerization techniques. Vinyl ether monomer was polymerized using a trifluoromethane sulfonic acid and methyl triflouoromethanesulfonate/tetrahydrothiophene initiator system in dichloromethane at -18^oC, and quantitatively terminated with labile azo compounds in order to obtain poly(vinyl ether) with well-defined molecular weight and end groups. This polymer was used in a subsequent blocking step in which azo groups were decomposed at 80^oC in the presence of methyl methacrylate and styrene monomer. In both copolymers, blocks of different chemical composition were segregated in the solid and melt-phase …
Electrochemical Polymerization And Analysis Of Some Aniline Derivatives, Bekir Sari, Muzaffer Talu
Electrochemical Polymerization And Analysis Of Some Aniline Derivatives, Bekir Sari, Muzaffer Talu
Turkish Journal of Chemistry
In this study, conductive homopolymers of o-chloroaniline, p-bromoaniline and N-methylaniline were synthesized electrochemically in perchloric acidic solution and their properties were analyzed. Initially, the maximum oxidation potential values of these monomer solutions were determined by Cyclic Voltammetry (CV). Their conductive polymers were then synthesized under a nitrogen atmosphere using a potentiostat. FTIR spectra were taken in order to analyze the structural properties of the resulting polymers. Thermogravimetric analysis (TGA) was conducted and surface micrographs were taken by a Scanning Electron Microscope (SEM). The conductivity levels of the polymers were determined by the Four Probe technique. Magnetic properties of the samples …
Electron Spectroscopy For Material Characterization, Ş. Süzer
Electron Spectroscopy For Material Characterization, Ş. Süzer
Turkish Journal of Chemistry
Basic principles of the two electron spectroscopic techniques, the x-ray photoelectron spectroscopy, XPS, and the Auger electron spectroscopy, AES, are given. Their utilization in material characterization are introduced through examples with application of these techniques to various surface related problems.
Separation Of Molybdenum, Vanadium And Nickel By Liquid-Liquid Extraction, T. Coşar, R. Zi̇yadanoğullari
Separation Of Molybdenum, Vanadium And Nickel By Liquid-Liquid Extraction, T. Coşar, R. Zi̇yadanoğullari
Turkish Journal of Chemistry
Elements in the ash of asphaltites that is used in thermal central for power generation units are Mo, V, U, Ti and Ni. The main goal of this study was to separate molybdenum, vanadium and nickel from the aqueous solution. The quantities of the above elements in solution were in the range of 50-80 ppm. The separate these elements from solution, the liquid-liquid extraction method was applied to samples. Alamine 336 was used as extractant. During the reduction-oxidation processes, single and multiple extraction methods were applied to the solution in combination. The quantities of molybdenum, vanadium and nickel in the …
Potentiometric Investigation Of The Effects Of Several Substituents On The Basicity Of Benzilidene-O-Hydroxyaniline, Esma Kiliç, Orhan Atakol, E. Canel, Zehra Ali̇beşeoğlu, Turgut Gündüz, Fitnat Köseoğlu
Potentiometric Investigation Of The Effects Of Several Substituents On The Basicity Of Benzilidene-O-Hydroxyaniline, Esma Kiliç, Orhan Atakol, E. Canel, Zehra Ali̇beşeoğlu, Turgut Gündüz, Fitnat Köseoğlu
Turkish Journal of Chemistry
Chloro-, bromo-, iodo-, nitro-, methoxy- and hydroxy-substituted benzilidene-o-hydroxyaniline were prepared in order to investigate the effects of substituents on the basicity of benzilidene-o-hydroxyaniline. For each substituent, three isomers -- ortho, meta and para -- were synthesised. Schiff bases were titrated potentiometrically with perchloric acid in nitrobenzene solvent at $25^{\circ}$C. All compounds gave well-shaped titration curves, from which half-neutralisation potentials were calculated. The trend in the values of half-neutralisation potentials of Schiff bases were explained in terms of the nature of the substituents. The applicability of the Hammett equation to the effect of substituents in Schiff bases in nitrobenzene solvent was …
On The Türker Angles In The Theory Of Total \Pi-Electron Energy, Ivan Gutman
On The Türker Angles In The Theory Of Total \Pi-Electron Energy, Ivan Gutman
Turkish Journal of Chemistry
The Türker angles $\theta, \alpha$ and $\beta$ are quantities invented by Lemi Türker, and are used in the theory of total $\pi$-electron energy $(E)$ of unsaturated conjugated hydrocarbons. We report here expressions for $\theta, \alpha$ and $\beta$ in terms of $E$ and the parameters $n$ (= half the number of carbon atoms) and $e$ (= the number of carbon-carbon bonds). The forms of these expressions are remarkably similar. Numerical calculation performed on a representative set of benzenoid hydrocarbons reveals that the dependence of the angles $\alpha$ and $\beta$ on molecular structure is very similar, and that their ratio is almost …
Strain Analysis Of The Kapidagi Peninsula Shear Zone In The Ocaklargranitoid, Nw Turkey, Rahmi̇ Aksoy
Strain Analysis Of The Kapidagi Peninsula Shear Zone In The Ocaklargranitoid, Nw Turkey, Rahmi̇ Aksoy
Turkish Journal of Earth Sciences
The Kapidagi Peninsula shear zone is a W-to NW-trending, moderately to steeply dipping, sinistral strike-slip shear zone that runs almost parallel to the northern coast of the peninsula. It is a minimum of 28 km in length and extends from Rikoz Cape in the west to the north of Çakil village in the east. A quantitative strain analysis is presented for the shear zone evolved in the Ocaklar Granitoid by a syn-shear granitod intrusion. Deformed autoliths in the granitoids were used as strain markers. Long, intermediate and short axes of autoliths were measured in 66 subareas across the shear zone. …
Crystallization Processes And Role Of Compositional Convection In Themacrolayer Formation In A Small Layered Complex, Bernard Plateovet
Crystallization Processes And Role Of Compositional Convection In Themacrolayer Formation In A Small Layered Complex, Bernard Plateovet
Turkish Journal of Earth Sciences
The Peloso complex is a 1000m thick gabbroic body composed of two main layered zones (ZA and ZB) that are made up of cyclic macrolayers of olivine gabbro, leucogabbronorite and anorthosite cumulates, and a third zone of unlayered quartz-gabbro (ZC) which may represent a residual liquid. Within a representative macrolayer, cryptic evolution of minerals can not be neglegted, showing that the crystallizing magma batch had a limited volume and was renewed between the formation of two successive macrolayers. The comparison between calculated parental magma density and densities of successive cumulates shows that the residual liquid was probably extracted by compositional …
Synthesis Of New Bisamidoxime Ligands And Their Monocharged Metal Complexes, Niyazi Biçak, Tülay Atay
Synthesis Of New Bisamidoxime Ligands And Their Monocharged Metal Complexes, Niyazi Biçak, Tülay Atay
Turkish Journal of Chemistry
This paper describes the synthesis of two new bisamidoxime ligands with dithioether connecting groups. The ligands were obtained from ethane dithiol in two steps; i) cyanoalkylation ii) oximation with hydroxylamine. Cyanoalkylation of ethanedithiol was carried out by condensing with chloro acetonitrile and base-catalysed addition of acrylonitrile, yielding bis(cyanomethylthio) ethane and bis(cyanoethyl thio) ethane, respectively. Upon subsequent oximation with hydroxylamine, these bisnitrile compounds gave corresponding bis(amidoxime) ligands in reasonable yields. The ligands behave as tetradentate ligands and on interaction with Cu(II), Ni(II), Co(II) chlorides produces monocharged metal complexes in a [ML]$^+$Cl$^-$ composition.
The Influence Of The Dispersion Of Boron Silicate On The Migration Of Non-Equilibrium Charge Carriers Generated By Eect Of An Electric Discharge, A.M. Hasanov
Turkish Journal of Physics
ESR was used in an investigation of the influence of Boron Silicate dispersion on the accumulation of paramagnetic centers (PC). It was observed that the rate of accumulation of PC increase by increasing of the grain size (r). At $r < 0.08$ mm the electrons ($F^+$-centers) are localized on the surface and with increasing grain size up to $0.08 < r < 0.22$ mm charge stratification takes place, the electrons are distributed in near-surface layer and the holes ($V$-centers) are localized in the bulk of the insulator. It was established that the transport of non-equilibrium charge carriers (NCC) from the bulk to the surface of Boron Silicate was due to a drift from the depth $(d \sim 10 \mu m)$ to a bulk-charge field generated by an electric discharge. The value of the surface field $E_s \sim 10^5 V/cm$ is determined by experimental results of the data. The kinetics of the isothermal annealing (300 K) are used to establish the influence of the surface field on the annihilation of NCC in the ''dead'' layer of separated charges.
Measurement Of The Compton And Coherent Scattering Differential Cross-Sections, Yakup Kurucu, Salih Erzeneoğlu, Rıdvan Durak, Yusuf Şahi̇n
Measurement Of The Compton And Coherent Scattering Differential Cross-Sections, Yakup Kurucu, Salih Erzeneoğlu, Rıdvan Durak, Yusuf Şahi̇n
Turkish Journal of Physics
The total atomic Compton and coherent scattering differential cross section of Al, Sn and Ta for 59.5 keV gamma rays of Am-241 point source have been measured for scattering angles $\theta=81^{\circ}$, $85.5^{\circ}$, $90^{\circ}$ and $94.5^{\circ}$ by a direct method with an energy dispersive x-ray spectrometer. The background correction and detection efficiency are also included the study. The experimental results are comparatively given with some available theoretical data obtained with some approximation methods.
Analytical Expressions Of Matrix Elements For Saxon-Woods Potential And Pad'{E} Approximations, Valentin L. R. Niculescu, Dumitru Catana
Analytical Expressions Of Matrix Elements For Saxon-Woods Potential And Pad'{E} Approximations, Valentin L. R. Niculescu, Dumitru Catana
Turkish Journal of Physics
The paper presents the analytical matrix elements of the kinetic hamiltonian in the oscillator base. The Pad'{e} approximations for the potential part (Saxon - Woods and alike) was used. From residue calculus the potential matrix elements are analytical. Many parts of these expressions can be computed once for ever. In this way the evaluation time can be reduced and the relations obtained are well suited for parallel computation.
^{19}F Nmr Study Of Flux-Line Dynamics In Fluorinated Yba_2cu_4o_8, Figen Tabak, Mavrizio Corti̇
^{19}F Nmr Study Of Flux-Line Dynamics In Fluorinated Yba_2cu_4o_8, Figen Tabak, Mavrizio Corti̇
Turkish Journal of Physics
Measurements of the ^{19}F NMR linewidth \Delta \nu and spin-lattice relaxation rate 1/T_1 have been performed in an oriented powder sample of fluorinated YBa_2Cu_4O_8 at temperatures 4 < T < 300 K and static magnetic fields 0.3 < H_0 < 9.4 T for Hollc. Thermal motion of flux lines was evidenced from the effect on NMR linewidth while 1/T_1 showed the effects due to interaction with Fermi liquid.
Dold-Kan Type Theorems For N-Types Of Simplicitial Commutative Algebras, Z. Arvasi̇, M. Koçak
Dold-Kan Type Theorems For N-Types Of Simplicitial Commutative Algebras, Z. Arvasi̇, M. Koçak
Turkish Journal of Mathematics
A functor from simplicial algebras to crossed \( n \)-cubes is shown to be an embedding on a reflexive subcategory of the category of simplicial algebras that contains representatives for all \( n \) types.
Crossed N-Cubes And N-Crossed Complexes Of Commutative Algebras, Z. Arvasi̇, M. Koçak
Crossed N-Cubes And N-Crossed Complexes Of Commutative Algebras, Z. Arvasi̇, M. Koçak
Turkish Journal of Mathematics
In this paper we will define crossed $\Bbb N$-cubes and n-crossed complexes of commutative algebras and construct a functor from the category of simplicial algebras to that of n-crossed complexes.
On Certain Varieties Of Semigroups, A. Tiefenbach
On Certain Varieties Of Semigroups, A. Tiefenbach
Turkish Journal of Mathematics
In this paper we generalize the class of completely regular semigroups (unions of groups) to the class of local monoids, that is the class of all semigroups where the local subsemigroups \( aSa \) are local submonoids. The sublattice of this variety \( (\mathbf{L}(\caL(\cam)) \) covers another lattice isomorphic to the lattice of all bands \( ([x^2 = x]). \) Every bundvariety \( \cau \) has as image the variety \( \Phi - \cau, \) which is the class of all semigroups, where \( \Phi \) is a \( \cau \)-congruence \( (a \Phi b \Leftrightarrow aSa = bSb). \) …
Locally Volume-Minimizing Codimension-One Foliation Of The Solid Torus, İ. Kocayusufoğlu, D. L. Jhonson
Locally Volume-Minimizing Codimension-One Foliation Of The Solid Torus, İ. Kocayusufoğlu, D. L. Jhonson
Turkish Journal of Mathematics
The aim of this paper is to construct a specific codimension-1 foliation of \( D^2 \times S^1 \) with one Reeb component, and to show that this foliation locally minimizes the volume among foliations with the boundary torus as a leaf.
Codes On Superelliptic Curves, F. Özbudak, M. Glukhov
Codes On Superelliptic Curves, F. Özbudak, M. Glukhov
Turkish Journal of Mathematics
The purpose of this paper is to apply superelliptic curves with a lot of rational points to construct rather good geometric Goppa codes.
Dynamical System Topology Preserved In The Presence Of Noise, Judy A. Kennedy, James A. Yorke
Dynamical System Topology Preserved In The Presence Of Noise, Judy A. Kennedy, James A. Yorke
Turkish Journal of Mathematics
We first give a precise definition of the terms ``topological horseshoe'' and ``generalized quadrilateral'' and then examine the behavior of a homeomorphism F on a locally compact, separable, locally connected metric space X (X is usually a manifold in applications) such that F restricted to some generalized quadrilateral Q in X is a topological horseshoe map. For a set Q \subset X we define and describe (1) the permanent set Z of Q to be \{x\in X:F^n(x)\in Q for all integers n\}, and (2) the entrainment set of Q to be E(Q)=\{x\in X: F^{-n} (x)\in Q for all sufficiently large …
On 3 Dimensional Isotropic Submaniolds Of A Space From, Takehiro Itoh, Koichi Ogiue
On 3 Dimensional Isotropic Submaniolds Of A Space From, Takehiro Itoh, Koichi Ogiue
Turkish Journal of Mathematics
We study 3-dimensional isotropic submanifolds of a space form with low-dimensional first normal space
On Derived Equivalences And Local Structure Of Blocks Of Finite Groups, Markus Linckelmann
On Derived Equivalences And Local Structure Of Blocks Of Finite Groups, Markus Linckelmann
Turkish Journal of Mathematics
No abstract provided.
From Simplicial Groups To Crossed Complexes, Z. Arvasi̇
From Simplicial Groups To Crossed Complexes, Z. Arvasi̇
Turkish Journal of Mathematics
In this paper, we will give a short proof of the construction of the crossed complex of groups by using the higher order Peiffer elements.
On The Validity Of The Borel-Hirzebruch Formula For Topological Actions, D. Dönmez
On The Validity Of The Borel-Hirzebruch Formula For Topological Actions, D. Dönmez
Turkish Journal of Mathematics
We defined an equivalence among group actions and find sufficient conditions for actions of compact connected Lie groups on Euclidean spaces for which the topological version of the Borel-Hirzebruch formula holds.
A Combinatorial Definition Of N-Types Of Simplicial Commutative Algebras, Z. Arvasi, M. Koçak, M. Alp
A Combinatorial Definition Of N-Types Of Simplicial Commutative Algebras, Z. Arvasi, M. Koçak, M. Alp
Turkish Journal of Mathematics
In this paper, we will give a description of the functor from the category of crossed $n$-cubes to that of simplicial commutative algebras and study a commutative algebra version of Loday's theorem on $n$-types of simplicial groups.