Fen Edebiyat Fakültesi / Faculty of Letters and Sciences
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Publication Embargo 2-Transitive Frobenius Q-Groups(2009) Erkoç, Temha; Güzel, Erhan; 123408; 2127A Q -group is a finite group all of whose irreducible complex characters are rationally- valued. In this paper, we find all 2-transitive Frobenius Q -groupsPublication Metadata only 24-Epibrassinolide Induces SSAT and Causes Caspase-Dependent Apoptosis In Different Prostate Cancer Cell Lines(2011) Bolkent, Şehnaz; Ünsal, Zeynep Narçin; ARISAN, ELİF DAMLA; YERLİKAYA, PINAR OBAKAN; 156421; 113920; 3894; 6125Publication Metadata only 4 4 Bipyridyl Vibrational Assignments and Force Field(Elsevier, 1995-04) Topaçlı, Arzu; AKYÜZ, SEVİM; 170067; 10127A normal coordinate analysis of 4,4′-bipyridyl (4,4′-bipy) is carried out to establish consistent vibrational assignment and to determine a Urey-Bradley force field. The potential energy distribution of 4,4′-bipy is calculated which has provided certainty for the assignments. Additional information is obtained from the vibrational spectra of M (4,4′-bipy)Cl2 complexes (where M = Zn, Cu or Cd) and calculated wave numbers of complexed 4,4′-bipy. Several vibrational modes of 4,4′-bipy in the IR and Raman spectra of the complexes are found to have upward shifts in frequency compared to those in the free molecule and the shifts are metal dependent. An explanation supported by the normal coordinate analysis is provided in terms of coupling with low frequency vibrations, particularly the M-N stretching frequencies.Publication Metadata only 5-Methylhydantoin: From isolated molecules in a low-temperature Aaon matrix to solid state polymorphs characterization(2017-12) Nogueira, Bernardo.A.; Canotilho J.; Eusébio MES; Henriques MSC; Paixão JA; Fausto R.; ILDIZ, GÜLCE ÖĞRÜÇThe molecular structure, vibrational spectra and photochemistry of 5-methylhydantoin (C4H6N2O2; 5-MH) were studied by matrix isolation infrared spectroscopy and theoretical calculations at the DFT(B3LYP)/6-311++G(d,p) theory level. The natural bond orbital (NBO) analysis approach was used to study in detail the electronic structure of the minimum energy structure of 5-MH, namely the specific characteristics of the σ and π electronic systems of the molecule and the stabilizing orbital interactions. UV irradiation of 5-MH isolated in argon matrix resulted in its photofragmentation through a single photochemical pathway, yielding isocyanic acid, ethanimine, and carbon monoxide, thus following a pattern already observed before for the parent hydantoin and 1-methylhydantoin molecules. The investigation of the thermal properties of 5-MH was undertaken by differential scanning calorimetry (DSC), polarized light thermal microscopy (PLTM) and Raman spectroscopy. Four different polymorphs of 5-MH were identified. The crystal structure of one of the polymorphs, for which it was possible to grow up suitable crystals, was determined by X-ray diffraction (XRD). Two of the additional polymorphs were characterized by powder XRD, which confirmed the molecules pack in different crystallographic arrangements.Publication Metadata only 5-Methylhydantoin: from isolated molecules in a low-temperature argon matrix to solid state polymorphs characterization(Amer Chemical Soc, 1155 16th St, Nw, Washington, Dc 20036 USA, 2017-07-20) Nogueira, Bernardo A.; Canotilho, J.; Eusebio, M. E. S.; Henriques, M. S. C.; Paixao, J. A.; Fausto, Rui; ILDIZ, GÜLCE ÖĞRÜÇ; 107326The molecular structure, vibrational spectra and photochemistry of 5-methylhydantoin (C4H6N2O2; 5-MH) were studied by matrix isolation infrared spectroscopy and theoretical calculations at the DFT(B3LYP)/6-311++G(d,p) theory level. The natural bond orbital (NBO) analysis approach was used to study in detail the electronic structure of the minimum energy structure of 5-MH, namely the specific characteristics of the sigma and pi electronic systems of the molecule and the stabilizing orbital interactions. UV irradiation of 5-MH isolated in argon matrix resulted in its photofragmentation through a single photochemical pathway, yielding isocyanic acid, ethanimine, and carbon monoxide, thus following a pattern already observed before for the parent hydantoin and 1-methylhydantoin molecules. The investigation of the thermal properties of 5-MH was undertaken by differential scanning calorimetry (DSC), polarized light thermal microscopy (PLTM) and Raman spectroscopy. Four different polymorphs of 5-MH were identified. The crystal structure of one of the polymorphs, for which it was possible to grow up suitable crystals, was determined by X-ray diffraction (XRD). Two of the additional polymorphs were characterized by powder XRD, which confirmed the molecules pack in different crystallographic arrangements.Publication Metadata only 5-Methylhydantoin: Structure, Spectroscopy, Photochemistry and Polymorphism(2017) Nogueira, Bernardo, A.; Canotilho, Joa; Eusebio, M. E. S.; Henriques, M. S. C.; Paixao, Antonia; Rui, Fausto; ILDIZ, GÜLCE ÖĞRÜÇ; 107326Publication Metadata only A Certain Class of Harmonic Mappings Related to Functions of Bounded Boundary Rotation(Eudoxus Press, Llc, 1424 Beaver Trail Drive, Cordova, Tn 38016 Usa, 2014-05) Yavuz Duman, Emel; Aydoğan, Melike; POLATOĞLU, YAŞAR; 199370; 111202; 35549Let V(k) be the class of functions with bounded boundary rotation and let S-H be the class of sense-preserving harmonic mappings. In the present paper we investigate a certain class of harmonic mappings related to the function of bounded boundary rotation.Publication Metadata only A certain class of harmonic mappings related to functions of bounded radius rotation(2018) Kahramaner, Yasemin; Yemişçi Şen, Arzu; POLATOĞLU, YAŞARLet R-k be the class of functions with bounded radius rotation and let S-H be the class of sense-preserving harmonic mappings. In the present paper we investigate a certain class of harmonic mappings related to the function of bounded radius rotation.Publication Metadata only A certain class of starlike log-harmonic mappings(Elsevier Science Bv, Po Box 211, 1000 Ae Amsterdam, Netherlands, 2014-11) Aydoğan, Melike; POLATOĞLU, YAŞAR; 35549; 199370In this paper we investigate some properties of log-harmonic starlike mappings. For this aim we use the subordination principle or Lindelof Principle (Lewandowski (1961) [71). (C) 2014 Elsevier B.V. All rights reserved.Publication Embargo A combinatorial discussion on finite dimensional Leavitt path algebras(Hacettepe Univ, Fac Sci, Hacettepe Univ, Fac Sci, Beytepe, Ankara 06800, Turkey, 2014) Esin, Songül; Güloğlu, İsmail; Kanuni, Müge; KOÇ, AYTEN; 112205; 145213Any finite dimensional semisimple algebra A over a field K is isomorphic to a direct sum of finite dimensional full matrix rings over suitable division rings. We shall consider the direct sum of finite dimensional full matrix rings over a field K. All such finite dimensional semisimple algebras arise as finite dimensional Leavitt path algebras. For this specific finite dimensional semisimple algebra A over a field K, we define a uniquely determined specific graph - called a truncated tree associated with A - whose Leavitt path algebra is isomorphic to A. We define an algebraic invariant kappa(A) for A and count the number of isomorphism classes of Leavitt path algebras with the same fixed value of kappa(A). Moreover, we find the maximum and the minimum K-dimensions of the Leavitt path algebras. of possible trees with a given number of vertices and we also determine the number of distinct Leavitt path algebras of line graphs with a given number of vertices.Publication Metadata only A combinatorial discussion on finite dimensional leavitt path algebras(2012) Esin, Songül; Güloğlu, İsmail; Kanuni, Müge; KOÇ, AYTEN; 112205; 145213Publication Metadata only A comparative study of auditory and visual event related coherences(Elsevier Science Bv, Po Box 211, 1000 Ae Amsterdam, Netherlands, 2012-09) Tülay, Elif; Turp Gölbaşı, Bilge; Güntekin, Bahar; BAŞAR, EROL; 142226; 204666Publication Metadata only A comparative study of the yellow dent and purple flint maize kernel components by Raman spectroscopy and chemometrics(2019-05-15) Kabuk, Hayrunnisa Nur; Kaplan, Ekin Su; Halimoğlu, Gökhan; Fausto, Rui; ILDIZ, GÜLCE ÖĞRÜÇIn this investigation the potential of micro-Raman spectroscopy, coupled to a simple, standard chemometric method (principal component analysis, PCA), as a fast, cheap, field method to investigate maize kernel components (endosperm, germ and peel) is demonstrated. Particular emphasis was given to the determination of the relative protein and amylose/amylopectin contents in maize endosperm of yellow dent and purple flint corn species, the two major maize varieties produced in Turkey. It is shown that the studied yellow dent corn type has a comparatively larger content of protein (3.4%) and a higher amylopectin/amylose ratio in the endosperm than the studied purple flint variety (a 11% decrease of amylopectin was found in going from the studied yellow dent to the purple flint corn), while the germs of the two species differ mostly by the presence of a slightly larger amount of starch in the case of the yellow dent corn, the oil composition of both species being identical within the resolution of the used method of analysis. The spectra of the maize peels reveal essentially the presence of cellulose and lignin in similar amounts in the two types of corn. (C) 2019 Elsevier B.V. All rights reserved.Publication Metadata only A Conformational Analysis and Vibrational Spectroscopic Investigation on 1,2-bis(o-carboxyphenoxy) Ethane Molecule(Elsevier Science Bv, Po Box 211, 1000 Ae Amsterdam, Netherlands, 2012-01) Balcı, Kubilay; Yapar, Gönül; Akkaya, Yasemin; Koch, A.; Kleinpeter, E.; AKYÜZ, SEVİM; 54889; 119404; 175409; 10127The minima on the potential energy surface of 1,2-bis(o-carboxyphenoxy)ethane (CPE) molecule in its electronic ground state were searched by a molecular dynamics simulation performed with MM2 force field. For each of the found minimum-energy conformers, the corresponding equilibrium geometry, charge distribution, HOMO-LUMO energy gap, force field, vibrational normal modes and associated IR and Raman spectral data were determined by means of the density functional theory (DFT) based electronic structure calculations carried out by using B3LYP method and various Pople-style basis sets. The obtained theoretical data confirmed the significant effects of the intra- and inter-molecular hydrogen bonding interactions on the conformational structure, force field, and group vibrations of the molecule. The same data have also revealed that two of the determined stable conformers, both of which exhibit pseudo-crown structure, are considerably more favorable in energy to the others and accordingly provide the major contribution to the experimental spectra of CPE. In the light of the improved vibrational spectral data obtained within the "SQM FF" methodology and "Dual Scale Factors" approach for the monomer and dimer forms of these two conformers, a reliable assignment of the fundamental bands observed in the experimental room-temperature IR and Raman spectra of the molecule was given, and the sensitivities of its group vibrations to conformation, substitution and dimerization were discussed. (C) 2011 Elsevier B.V. All rightsPublication Metadata only A Density Functional Theory based study of the solvent effects on the experimental vibrational spectra of 4-aminopyrimidine(2017) Akkaya, Yasemin; Balcı, Kubilay; AKYÜZ, SEVİM; 175409; 54889; 10127Publication Metadata only A developmental study concerning the importance of somatic marker hypothesis(2013) ŞANDOR, SERRA; 107162Publication Metadata only A Fourier-transform infrared and laser-Raman spectroscopic investigation of 4,4′-bipyridyl-transition metal(II) tetracyanonickelate clathrates(1996-03) Davies, J. Eric D.; AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL; 10127The FT-IR and Raman spectra are reported of M(4,4-bipyridyl)Ni(CN)4nG (where M = Mn, Fe, Co, Cu or Zn and G = benzene or aniline;n = 0–2) clathrates. The host structure consists of a three-dimensional rigid lattice formed by infinite polymeric layers of {M-Ni(CN)4} and 4,4-bipyridyl bridges between the metal (M) atoms of the adjacent polymeric layers. Bidentate 4,4-bipyridyl molecules are found to be centrosymmetric in the structure.Publication Embargo A mechanism for the dependence of sunspot group tilt angles on cycle strength(Iop Publıshıng Ltd, Temple Circus, Temple Way, Bristol Bs1 6Be, England, 2015-11-01) Işık, EmreThe average tilt angle of sunspot groups emerging throughout the solar cycle determines the net magnetic flux crossing the equator, which is correlated with the strength of the subsequent cycle. I suggest that a deep-seated, non-local process can account for the observed cycle-dependent changes in the average tilt angle. Motivated by helioseismic observations indicating cycle-scale variations in the sound speed near the base of the convection zone, I determined the effect of a thermally perturbed overshoot region on the stability of flux tubes and on the tilt angles of emerging flux loops. I found that 5-20 K of cooling is sufficient for emerging flux loops to reproduce the reported amplitude of cycle-averaged tilt angle variations, suggesting that it is a plausible effect responsible for the nonlinearity of the solar activity cycle.Publication Metadata only A Microsoft Visual Basic software for B spline solution of the one dimensional heat equation(2009) Çağlar, Hikmet; Çağlar, Nazan; Özer, Mehmet; CUHACI, LEVENT; 114368; 112369; 110809; 2509Publication Metadata only A microsoft visual Basic software for B-Spline solution of the one-dimensional heat equation(2008) Çağlar, Hatice Nazan; Çağlar, Süleyman Hikmet; Özer, Mehmet; CUHACI, LEVENT; 110809; 114368; 2509; 112369