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Articles 10591 - 10620 of 10730
Full-Text Articles in Physical Sciences and Mathematics
Conducting Polymer Grafts Of Polypyrrole, Levent Toppare
Conducting Polymer Grafts Of Polypyrrole, Levent Toppare
Turkish Journal of Chemistry
Conducting polymer grafts of pyrrole with poly[(methyl methacrylate)-co-(2-(N-pyrollyl) ethyl methacrylate)] wwere synthesized via elctrochemical polymerization of pyrrole in different media. Samples were characterized by SEM, thermal analysis and conductivity measurements.
Crystal Structure Effect In Radiation-Induced Solid-State Polymerization Of Acrylamide, Ali Usanmaz
Crystal Structure Effect In Radiation-Induced Solid-State Polymerization Of Acrylamide, Ali Usanmaz
Turkish Journal of Chemistry
Crystal structure of arcylamide at -150^{\circ}C was studied to understand the role of the crystal structure on the reaction mechanism of radiation-induced polymerization in the solid-state. Acrylamide crystallizes in the monoclinic unit cell with the unit cell parameters as ; a=828.0(2) pm, b=578.0(4) pm, c=974.9(2) pm, \beta=119.62(4)^0, space group =P 2_1/c, Z=4 molecules/unit cell, d_x = 1.165 g/cm^3. From the results of the structural data a polymerization mechanism in the solid-state is suggested. The radiation damage in single crystal of acrylamide was also investigated in detail. The result showed the formation of the amorphous polymer, that phase separated from the …
Electrical Conductivities Of Poly (Alkyl Vinyl Ketones) Reacted With Dopant Solutions, Jun Hui Ma, J. David Tauber, Ülkü S. Ramelow
Electrical Conductivities Of Poly (Alkyl Vinyl Ketones) Reacted With Dopant Solutions, Jun Hui Ma, J. David Tauber, Ülkü S. Ramelow
Turkish Journal of Chemistry
Poly ethyl vinyl ketone (PEVK) and poly methyl vinyl ketone (PMVK) were prepared using photochemical processes. The irradiation of monomers with UV light provides a new method, different from the methods previously used for the polymerization of these monomers. FTIR and UV spectroscopies were used for the structure and reaction mechanism of the polymers. NMR was used to calculate the conversion percentage of MVK and EVK polymers. The conductivity change at various temperatures was traced during reactions of PMVK and PEVK with various dopant concentrations and the activation energy of these reactions were calculated by adding dopants and by adjusting …
A Two-Dimensional Monte Carlo Polymerization Of 5-Membered Rings, Okan Esentürk, H. Önder Pamuk, E. Yurtsever
A Two-Dimensional Monte Carlo Polymerization Of 5-Membered Rings, Okan Esentürk, H. Önder Pamuk, E. Yurtsever
Turkish Journal of Chemistry
A modification of the kinetic growth model in two dimensions for the polymerization of 5-membered rings is presented. The preliminary results reveal the validity of the modified model.
Calculation Of Spreading Pressure Of Water On Cellulosic Films From Contact Angle Data, H. Yıldırım Erbi̇l
Calculation Of Spreading Pressure Of Water On Cellulosic Films From Contact Angle Data, H. Yıldırım Erbi̇l
Turkish Journal of Chemistry
The correlations between the surface properties of the modified cellulose papers with their toner compatibility were investigated. The surface tension components of the cellulosic films, their interfacial tension with the liquid drops and the work of adhesion components were calculated using van Oss-Good's One-Liquid contact angle approach. The electron donor (or Lewis base) \gamma^- components of the cellulosic films were found to represent the main interactions with the the electron acceptor (acidic) \gamma^+ components of the contacting liquids. Allyl ketene dimer (AKD) grafting of the cellulose affected the surface properties; the higher the substitution of the hydroxyl group, the smaller …
Phase Transition Of Hydrolyzed Polyacrylamide Gels In Aqueous Solutions Of Poly(Ethylene Glycol), Nilhan Kayaman, Oğuz Okay, B. M. Baysal
Phase Transition Of Hydrolyzed Polyacrylamide Gels In Aqueous Solutions Of Poly(Ethylene Glycol), Nilhan Kayaman, Oğuz Okay, B. M. Baysal
Turkish Journal of Chemistry
Hydrolyzed polyacrylamide gels immersed in aqueous solutions of poly(ethylene glycol) (PEG) of molecular weight 300 exhibit a discontinuous volume change upon continuous increase of the PEG concentration in the external solution. As the duration of hydrolysis increases, that is, as the proportion of the ionic groups on the network chains increases, the critical concentration of PEG required for a discontinuous volume change rises and, also, the magnitude of the volume collapse becomes larger. Experimental results indicate that the gel collapse in PEG solution is due to the osmotic deswelling of the ionic gel rather than due to a complex formation …
A Quantum-Chemical Investigation On 5,5'-Bi(1h-1.2,4-Triazole)), A. A. İki̇zler, R. Abbasoğlu, N. Saltek, M. Şeri̇fova
A Quantum-Chemical Investigation On 5,5'-Bi(1h-1.2,4-Triazole)), A. A. İki̇zler, R. Abbasoğlu, N. Saltek, M. Şeri̇fova
Turkish Journal of Chemistry
The conformational analysis of flexible 5,5'-bi(1H-1,2,4-triazole) molecule containing various reaction centers has been performed by the semiempirical methods MNDO,AM1 and PM3, and the internal rotation barrier calculated. The most stable conformation of the molecule has been determined to be the planar trans conformation. According to the three methods, 5,5'-bi(1H-1,2,4-triazole) molecule (C) has been found to be relatively more stable than its tautomer 3,3'-bi(1H-1,2,4-triazole)(B) and to be less stable than its other tautomer 3,3'-bi(4H-1,2,4-triazole)(A). Moreover, the electronic properties of 5,5'-bi(1H-1,2,4-triazole) molecule and the effect of conformational changing on electronic and geometric properties have also been investigated. To determine the protonation sites …
High Rates Of Fluorescence Quenching Between Perylene Dodecyldiimide And Certain \Pi-Electron Donors, S. İçli̇, H. İci̇l, İ. Gürol
High Rates Of Fluorescence Quenching Between Perylene Dodecyldiimide And Certain \Pi-Electron Donors, S. İçli̇, H. İci̇l, İ. Gürol
Turkish Journal of Chemistry
Perylene bis-n-dodecyl diimide is found to quench fluorescenc emissions of naphthalene, phenanthrene and dihydrocarbazolocarbazole molecules at rates of 4.4\times10^{11}, 2.8\times10^{12} and 2.5\times10^4 M^{-1} sec^{-1}, in respective order of aromaticity. These unusulally high rates of fluorecence quenchings are attributed to Perrin model static quenching and presence of electron transfer through singlet excited state of perylene diimide. Calculated free energy of electron transfer, \Delta G_{ET}=-120.5 kJ/mol, between perylene diimide and dihydrocarbazolocarbazole is taken as evidence for observation of high fluorescence quenching rate for carbazolocarbazole molecule. Keywords: Fluorescence quenching, Photoenergy transfer, Perylene diimide and Carbazolocarbazole
Possible Roles Of Transition Metals In Cloudwater Relative To The Solar Short-Wave Radiation Absorption Anomaly, Xudong Huang, S. Sinan Keski̇n, Francis Pink, İlhan Ölmez
Possible Roles Of Transition Metals In Cloudwater Relative To The Solar Short-Wave Radiation Absorption Anomaly, Xudong Huang, S. Sinan Keski̇n, Francis Pink, İlhan Ölmez
Turkish Journal of Chemistry
Measurements of the absorption of solar short-wave radiation by clouds exceed those predicted by theoretical calculations. In order to understand the roles of minor and trace species in this absorption anomaly, cloudwater samples were collected from individual precipitating clouds and analyzed for trace metals and anionic species. Two generalized approaches were used to assess the direct impact of the absorption of solar short-wave radiation by transition metals and/or their anionic complexes. Additionally, it was suggested that iron and manganese may act as catalyts in the formation of sulfate aerosols which efficiently scatter solar radiation.
Constituents Of Salvia Verticillata, Ufuk Sönmez, Gülaçtı Topçu, Ayhan Ulubelen
Constituents Of Salvia Verticillata, Ufuk Sönmez, Gülaçtı Topçu, Ayhan Ulubelen
Turkish Journal of Chemistry
Three new and fourteen known compounds were isolated from the roots of {\it Salvia verticillata L.} Spectral methods were used for the structure determination besides TLC comparisons with authentic samples for the known compounds.
The Reliability Of Jung-Biggs-Moorhead Method For Cholesterol Determination In The Presence Of Ergosterol, Lemi Türker, Şahinde Demi̇rci̇, Marjan Akdağ
The Reliability Of Jung-Biggs-Moorhead Method For Cholesterol Determination In The Presence Of Ergosterol, Lemi Türker, Şahinde Demi̇rci̇, Marjan Akdağ
Turkish Journal of Chemistry
In the present study, the reliability of Jung-Biggs-Moorhead method for cholesterol determination has been tested in the presence of another steroid, ergosterol. It was observed that presence of ergosterol interferes with the absorbance measurement of cholesterol. When both steroids are present in the sample maximum absorption wavelength are not shifted by the mutual interaction but absorbance values are changed considerably. Therefore this method may be used only for qualitative bu not quantitative analysis for cholesterol in the presence of ergosterol.
Immobilization Of Glucose Oxidase And Urease In Hydrogel Matrices, İhsan Gürel, M.Yakup Arica, Vasıf Hasirci
Immobilization Of Glucose Oxidase And Urease In Hydrogel Matrices, İhsan Gürel, M.Yakup Arica, Vasıf Hasirci
Turkish Journal of Chemistry
Immobilization of glucose oxidase and urease in hydrogels of 2-hydroxyethyl methacrylae, and N-vinyl pyrrolidone (NVP) was achieved by irradiation (using UV kand \gamma- rays). The effect of radiation on entrapment efficiencies, retention of activities and swelling rates was obtained. To optimize the system, duration of exposure, reaction temperature, co-monomer concentrations, initiator and cross linker compositions were varied. The repeated reusability of the generated products was also tested. It was found that\gamma-irradiation at very low temperatures did not have a detrimental effect on the enzyme activity. Incorporation of more hydrophilic monomer (NVP), influenced matrix morphology and entrapment efficiencies and retained enzyme …
Synthesis And Characterisation Of Anhydrous Magnesium Phosphate Mg$_3$(Po$_4$)$_2$, A. Baykal, M. Kizilyalli, R. Kniep
Synthesis And Characterisation Of Anhydrous Magnesium Phosphate Mg$_3$(Po$_4$)$_2$, A. Baykal, M. Kizilyalli, R. Kniep
Turkish Journal of Chemistry
The synthesis and characterization of anhydorus Mg_3(PO$_4)_2 was investigated. Mg_3(PO$_4)_2 is reported to have similar structural arrangements with Co_3(PO_4)_2 and \gamma-Zn_3(PO_4)_2 compounds. The sample was prepared by a new technique which is the reaction of MgCl_2.6H_2O and Na_3PO_4.12H_2O solutions at pH=5.1, which was adjusted by adding concentrated H_3PO_4 to the reaction mixture and heating the precipitated product at 600^{\circ}C untill constant weight. The purity of the product was checked by X-ray powder diffraction, IR, density measurement, SEM and DTA analysis. The monoclinic unit cell dimensions of product are a=7.605 (2), b=8.233 (3), c=5.080 (1)A^{\circ} and \beta= 94.19^{\circ} (3), which was …
A Study Of The Thermodynamical Interactions Of Bisphenol-A Polycarbonate With Some Solvents By Gas Chromatography, Özlem Cankurtaran, Ferdane Yilmaz
A Study Of The Thermodynamical Interactions Of Bisphenol-A Polycarbonate With Some Solvents By Gas Chromatography, Özlem Cankurtaran, Ferdane Yilmaz
Turkish Journal of Chemistry
Retentin diagrams of polycarbonate for n-nonane, ethyl acetate and n-butyl acetate were obtained using inverse gas chromatography in the temperature range 80-240^{\circ}C. The specific retention volumes, V^{\circ}_{g} the Flory-Huggins interaction parmeters, \chi^{\infty}_{12}, interaction parameters, \chi^{\ast}_{12}, and effective exchange-energy parameters \bar{X}_{12} of the equation-of-state theory of polycarbonate for n-octane, n-nonane, n-decane, ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate and isoamyl acetate were obtained in the temperature range 200-240^{\circ}C. The parameter \delta_2 was estimated to be 10.7 (cal/cm^3)^{1/2} at room temperature using the \chi^{\infty}_{12} extrapolated to room temperature. Keywords: Bisphenol-A polycarbonate, polymer-solvent interactions, inverse gas chromatography, solubility parameter.
Photoelectron Spectroscopy: A Tool In Sorption Studies, Şefik Süzer, Hasan N. Erten
Photoelectron Spectroscopy: A Tool In Sorption Studies, Şefik Süzer, Hasan N. Erten
Turkish Journal of Chemistry
Photoelectron spectroscopy using AlK\alpha (h\nu=1486.3 eV) has been applied to study the sorption of Cs^+, Sr^{2+}, Ba^{2+}, Zn^{2+} and Co^{2+} on magnesite kaolinite, smectite and chlorite. From the observed intensities of photoelectron peaks it was determined that in magnesite the sorption affinity of the above ions follow the order: Ba^{2+}>Co^{2+}\congSr^{2+}\congZn^{2+}>Cs^+. The order for the sorption of Ba^{2+} and Cs^+ are also determined as chlorite>magnesite>smectite>kaolinite and smectite>chlorite\congkaolinite>magnesite, respectively.
A Topological Approach To The Stabilities Of Isomeric Hückel And Mobius Type Cyclacenes, Lemi Türker
A Topological Approach To The Stabilities Of Isomeric Hückel And Mobius Type Cyclacenes, Lemi Türker
Turkish Journal of Chemistry
Within the constraints of Hückel molecular orbital theory, Hückel and Mobius type cyclacenes were investigated in terms of their angle of total \pi-electron energy, O_{\pi}, and cos O_{\pi} to find out how structural changes affect the stabilities. It has been theoretically deduced that as the number of benzenoid rings (R) increases the isomeric Hückel and Mbius type cyclacenes should have comparable stabilities, although for low values of R odd-Hückel type and even-Mobius type are predicted to be more stable.
Hydrolysis And Condensation Reactions Of Methacrylate-Modified Aluminum Alkoxides, Ertuğrul Arpaç, Efraim Avşar
Hydrolysis And Condensation Reactions Of Methacrylate-Modified Aluminum Alkoxides, Ertuğrul Arpaç, Efraim Avşar
Turkish Journal of Chemistry
The hydrolysis of aluminum tri-sec-butoxide and compounds obtained by substituting the larger functional groups for the present alkly groups in Al(O-sec-Bu)_3, and the reaction of these products with a polymerizable organic ligand, i.e. methacrylic acid, were studied together with the hydrolysis reactions of the final products. A good method of preparing high-tech materials and new composites uses organo-substituted silicon esters and/or alkoxides of various elements in a polycondensation process. Introducing a suitable organic network into the inorganic backbone gives desirable properties in new coating materials. The preparation of such materials is possible via the hydrolysis of metal alkoxides. Usually, different …
Potentiometric And Spectroscopic Determinaton Of Acid Dissociation Constants Of Some Phenols And Salicylic Acids, Rahmiye Aydin, Ulviye Özer, Naciye Türkel
Potentiometric And Spectroscopic Determinaton Of Acid Dissociation Constants Of Some Phenols And Salicylic Acids, Rahmiye Aydin, Ulviye Özer, Naciye Türkel
Turkish Journal of Chemistry
The dissociation constant of the catechol derivatives 4-nitrocatechol (NCAT), 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DBHA), 3,4-dihydroxyhenylacetic acid (3,4-DPHA) and 3,4-dihydroxycinnamic acid (3,4-DHCA) were identified in 0.1M NaClO_4 ionic medium, at t=25^{\circ}C, by potentiometry. In addition, the first and second dissociation constants of the salicylic acid derivatives 5-nitrosalicylic acid (5-NSA), 4-hydroxysalicylic acid (4-HSA) 5-nitrosalicylic acid (5-HSA) were also determined by potentiometry. Furthermore, the second acid dissociation constants of these ligands were evaluated in I=0.1M NaClO_4 ionic medium, at a temperature of 25^{\circ}C by computer analysis of spectroscopic data.
Exotic Structures And Adjunction Inequality, Selman Akbulut, Rostislav Matveyev
Exotic Structures And Adjunction Inequality, Selman Akbulut, Rostislav Matveyev
Turkish Journal of Mathematics
No abstract provided.
On Some Bounds For The Solutions Of The Semi-Discretized Time-Dependent Ginzburg-Landau Equations, Erhan Coşkun
On Some Bounds For The Solutions Of The Semi-Discretized Time-Dependent Ginzburg-Landau Equations, Erhan Coşkun
Turkish Journal of Mathematics
We study the two-dimensional system of Time-Dependent Ginzburg-Landau Equations (TDGL) for modeling a thin film of superconductor subject to a uniform magnetic field. We discretize the TDGL for the space variables using bond variables and staggered grid partitioning technique. By investigating the temporal evolution of semi-discrete Helmholtz enery functional and that of Semi-discretized TDGL, we provide bounds for some observable physical quantities of interest such as superelectron density, supercurrent density, charge density, electric field, and induced magnetic field.
Kirby Calculus In Manifolds With Boundary, Justin Roberts
Kirby Calculus In Manifolds With Boundary, Justin Roberts
Turkish Journal of Mathematics
Suppose there are two framed links in a compact, connected 3-manifold (possibly with boundary, or non-orientable) such that the associated 3-manifolds obtained by surgery are homeomorphic (relative to their common boundary, if there is one.) How are the links related? Kirby's theorem gives the answer when the manifold is S^3, and Fenn and Rourke extended it to the case of any closed orientable 3-manifold, or S^1 \tilde{\times} S^2. The purpose of this note is to give the answer in the general case, using only minor modifications of Kirby's original proof.
The Hardy -Littlewood-Sobolev Inequality For Non-Isotropic Riesz Potentials, İnan Çinar
The Hardy -Littlewood-Sobolev Inequality For Non-Isotropic Riesz Potentials, İnan Çinar
Turkish Journal of Mathematics
In this study the inequality of Hardy-Littlewood-Sobolev type are established for non-isotropic generalized Riesz potential depending on \lambda -distance. In this paper we establish analogues of the well known Hardy-Littlewood-Sobolev inequality (see[3]) for Riesz potentials with non-isotropic kernel depended on \lambda distance. Note that different problems for convolution type integrals with kernels, depending on \lambda-distance were considered in [1] and [2].
Pin-Structures On Surfaces And Quadratic Forms, A. Degtyarev, S. Finashin
Pin-Structures On Surfaces And Quadratic Forms, A. Degtyarev, S. Finashin
Turkish Journal of Mathematics
A correspondence between various Pin-type structures on a compact surface and quadratic (Iinear) forms on its homology is constructed. Sum of structures is defined and expressed in terms of these quadratic forms and in terms of Whitney sum of Spin structures.
Locally Finite Barely Transitive Permutation Group With Almost Nilpotent Point Stabilizers, Mahmut Kuzucuoğlu
Locally Finite Barely Transitive Permutation Group With Almost Nilpotent Point Stabilizers, Mahmut Kuzucuoğlu
Turkish Journal of Mathematics
We show that the groups mentioned in the title are solvable. Moreover, a point stabilizer H of the locally finite barely transitive group G is almost nilpotent, whenever the indices H : H \cap H^g (g \in G) have a finite upper bound.
About Some Normal Subgroups Of Hecke Groups, İsmail Naci Cangül
About Some Normal Subgroups Of Hecke Groups, İsmail Naci Cangül
Turkish Journal of Mathematics
In this work we study the suucture of some special normal subgroups of Hecke groups. Particwarly those of genus O and 1 are studied by means of the regwar map theory which has been a growing subject in recent years. As a nice application, we calcwate the total number of genus 1 normal subgroups for a given index.
Nv-P-Groups With Nilpotent Centralizers, Ali Osman Asar, Aynur Yalincaklioğlu
Nv-P-Groups With Nilpotent Centralizers, Ali Osman Asar, Aynur Yalincaklioğlu
Turkish Journal of Mathematics
In this work a sufficient condition is given for an NC-p-group to have an epimorphic image which is an NF-p-group.
An Application Of Monodromy Groupoid, Osman Mucuk
An Application Of Monodromy Groupoid, Osman Mucuk
Turkish Journal of Mathematics
The monodromy groupoid was first inlioduced by Pradines in [7] and developed by Mucuk in [6] In this paper we give an application of the monodromy groupoid.
Locally Topological Groupoids, Osman Mucuk
Locally Topological Groupoids, Osman Mucuk
Turkish Journal of Mathematics
The notion of Iocally topological groupoid was introduced by Aof and Brown in [2]. On the other hand in [6] by Mackenzie a topological groupoid MG, called monodromy groupoid, is constructed. In this paper we prove that this groupoid MG gives a Iocally topological groupoid.
The Spectra And Fine Spectra For P-Cesáro Operators, Cafer Coşkun
The Spectra And Fine Spectra For P-Cesáro Operators, Cafer Coşkun
Turkish Journal of Mathematics
In [6], Rhaly computed the spectrum of p-Cesaro operator on the Hilbert space l_2 = {x = (x_k): \Sigma_k IX_kl^2 < infinite}. In the present paper, we study the spectrum and fine spectrum for p-Cesáro operators acting on C_o, the space of null sequences.
Painlevé Analysis And Infinite Lie Symmetries Of The Complex Modified Korteweg-De Vries-Ii Equation, Abulgassim Ali Muhammad, Mehmet Can
Painlevé Analysis And Infinite Lie Symmetries Of The Complex Modified Korteweg-De Vries-Ii Equation, Abulgassim Ali Muhammad, Mehmet Can
Turkish Journal of Mathematics
The Painleve analysis developed by Weiss et al. [9] for nonlinear partial differential equations is applied to the CMKdV-II equation. It has been shown that this equation passes the Painleve test. By specializing the arbitrary functions that appear in the phi series expansions found in the test, one obtains a system of partial differential equations for the formally arbitrary data. For specific systems, and conjectured in general, these equations are integrable. The form of the resulting reduction enables the identification of integrable reductions of the original systems. Assuming u_i = \upsilon_i = 0, i >= 2 we obtain conditions to …