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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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Publication Metadata only Influence of competitive hydrogen bonding between hard and soft segments on the properties of siloxane and polyether-based segmented copolymers.(Amer Chemical Soc, 1999) Department of Chemistry; Department of Chemistry; N/A; Yılgör, İskender; Burgaz, Engin; Metin, Burak; Yurtsever, İsmail Ersin; Yılgör, Emel; Faculty Member; Undergraduate Student; Undergraduate Student; Faculty Member; Researcher; Department of Chemistry; College of Sciences; College of Sciences; N/A; 24181; 17956; N/A; N/A; 40527N/APublication Metadata only Crystal structure of tetrasodium octaeuropium(ii) [octaphosphido(3-)]-bis[diphosphido(4-)]tetraaluminate(iii),NA 4EU8[AL4P8(P2) 2](Walter de Gruyter, 1998) Carrillo-Cabrera, W.; Peters, K.; Von Schnering, H.G.; Department of Chemistry; Somer, Mehmet Suat; Faculty Member; Department of Chemistry; College of Sciences; 178882N/APublication Metadata only A two-dimensional Monte Carlo polymerization of 5-membered rings(Scientific Technical Research Council Turkey, 1997) Esentürk, O.; Pamuk, H. A.; Department of Chemistry; Yurtsever, İsmail Ersin; Faculty Member; Department of Chemistry; College of Sciences; 7129A 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.Publication Metadata only Quantum chaos: a route through mixed-mode dynamics(Scientific and Technical research Council of Turkey - TUBITAK/Türkiye Bilimsel ve Teknik Araştırma Kurumu, 1997) Department of Chemistry; Yurtsever, İsmail Ersin; Faculty Member; Department of Chemistry; College of Sciences; 7129The quantal-classical mixed-mode dynamics provides a convenient tool for studying the transition from classical to quantum dynamics. In this work nonlinearly coupled oscillator systems whose classical motion display chaos are investigated under the time-dependent self-consistent-field approach so that one of the modes can be treated quantum mechanically. Lyapunov exponents for the mixed-mode system are defined through the use of Hamilton-Jacobi-like equations of motion for the quantal wavepacket. The classical modes seem to be more regularized when they are under the effect of quantum fields, however the Lyapunov exponents of the mixed-mode dynamics agree extremely well with those from classical calculations showing that chaos still survives in the mixed-mode philosophy.Publication Metadata only Tetrarubidium nonagermanide(4-) ethylenediamine, Rb-4[Ge-9][en](Wiley, 1998) Carrillo-Cabrera, Wilder; Peters, Eva Maria; Peters, Karl; von Schnering, Hans Georg; Department of Chemistry; Somer, Mehmet Suat; Faculty Member; Department of Chemistry; College of Sciences; 178882Orange crystals of Rbd(4)[Ge-9][en] are obtained after the exchange reaction of a solution of 'NaGe2.25' (precursor) in ethylenediamine (en) with solid RbI at 363 K, followed by slow cooling. The compound is very sensitive to oxidation and hydrolysis. The thermal decomposition in dynamic vacuum starts at 350 K with the complete loss of en followed by the sublimation of Rb in four steps (Rb8Ge25, Rb8Ge44, RbxGe136 with x less than or equal to 16, Ge). The Raman spectrum shows the characteristic bands of the [Ge-9](4-) anion (151, 163, 185 and 222 cm(-1)). Rb-4[Ge-9][en] crystallizes in a new structure type (space group P2(1)/m; a=15.353 Angstrom, b = 16.434 Angstrom, c = 15.539 Angstrom, beta =113.75 degrees; Z = 6; Pearson code mP198-40), which can be described as a hierarchical derivative of the structures of Al4YbMo2 and CrB4 (initiators) formed by partial atom-to-aggregate replacement: B-4[square 1][Cr] (=) over cap Al-4[Yb][Mo](2) (=) over cap Rb-4[Ge-9][en](1-2). Three crystal lographic independent [Ge-9](4-) clusters with different orientations are embedded in a Lt-connected 46(5) net formed by the Rb atoms, a network of condensed tetraasteranes. The clusters are distorted monocapped tetragonal antiprisms with D-1(Ge-Ge) = 2.57 Angstrom (16 x) and D-2(Ge-Ge) = 2.84 Angstrom (4x). The atoms of clusters with D1 and D2 lie at the surface of a rotational ellipsoid (a=b=2.136 Angstrom, c=2.431 Angstrom). The en molecules are located in open channels along [(1) over bar 0 1]. The coordinations [Ge-9] Rb-12/14 and Rb [Ge-9](4/12) en(2/8) show that the first step of solvation do not separate the cations from the cluster anions.Publication Metadata only The [Sn-5](2-) cluster compound [K-(2,2,2-crypt)](2)Sn-5 - Synthesis, crystal structure, Raman spectrum, and hierarchical relationship to CaIn2(Wiley, 1999) Carrillo-Cabrera, Wilder; Peters, Eva-Maria; Peters, Karl; Kaupp, Martin; von Schnering, Hans Georg; Department of Chemistry; Somer, Mehmet Suat; Faculty Member; Department of Chemistry; College of Sciences; 178882Dark red crystals of [K-(2,2,2)-crypt)](2)Sn-5 precipitate after the reaction of (2,2,2)-crypt with a solution of K1.33Sn in liquid ammonia at room temperature. The compound is sensitive to oxidation and hydrolysis. The sequence of Raman bands (104, 120, 133 and 180 cm(-1)) is characteristic for the trigonal bipyramidal closo-[Sn-5](2-) cluster anion. The wave numbers correspond with the data from Hartree-Fock calculations (114, 128, 142 and 187 cm(-1)). The compound crystallizes trigonally (a = 11.736 Angstrom, c = 22.117 Angstrom, Z = 2, space group (No. 165); Pearson code hP262), isotypic with [Na-(2,2,2)-crypt)](2)Pb-5. The atoms of the cluster show strange anisotropic displacements, which are perfectly reducible to a helical rigid-body motion around and along [001] (libration: +/-9.5 degrees; translation +/-0.29 Angstrom). The structure can be described as a hierarchical derivative of the initiator CaIn2 (P6(3)/mmc, hP6), generated by an atom-to-aggregate replacement: [Ca][In](2) = [Sn-5][K @ C36H72N4O12](2). Thus, the distribution of the [Sn-5](2-) Zint1 anions is hexagonal primitive, and the cation complexes are located close to the centers of trigonal superprisms formed by Sn5 clusters.Publication Metadata only Crystal structure of tetrasodium octastrontium catena-[octaphosphido(3-)]-[diphosphido(4-)]tetraaluminate(iii) [diphosphide(4-)], NA4SR8[AL4P8(P2)][P 2](Walter de Gruyter, 1998) Carrillo-Cabrera, W.; Peters, K.; Von Schnering, H.G.; Department of Chemistry; Somer, Mehmet Suat; Faculty Member; Department of Chemistry; College of Sciences; 178882N/APublication Metadata only Experimental and numerical investigation of thermal effects in end-pumped Cr/sup 4+/: forsterite lasers near room temperature(Optica Publishing Group, 1997) Department of Physics; Department of Physics; Sennaroğlu, Alphan; Yılmaz, Mehmet Burak; Faculty Member; Undergraduate Student; Department of Physics; College of Sciences; College of Sciences; 23851; N/ATheory of cw thermal loading in saturable absorbers with temperature-dependent lifetime is presented. Excellent agreement with experimental data is obtained with use of chromium-doped YAG saturable absorbers.Publication Metadata only Microstructure and tribological behavior of CF/PEEK composites: effect of thermal history on matrix and surface morphologies(American Chemical Society (ACS), 1998) Sinmazcelik, T; Curgul, I; Department of Chemistry; Department of Chemistry; Yılgör, Emel; Yılgör, İskender; Researcher; Faculty Member; Department of Chemistry; College of Sciences; College of Sciences; N/A; 24181N/APublication Metadata only Crystal structure of tetrasodium octaeuropium(ii) pentaphosphido(3-)-diphosphido(4-)-digallate(iii) catena-triphosphido(3-)-diphosphido(4-)-digallate(iii), NA4EU8[GA2P5(P2)][GA 2P3(P2)](Walter de Gruyter, 1998) Carrillo-Cabrera, W.; Peters, K.; Peters E. M.; Von Schnering, H.G.; Department of Chemistry; Somer, Mehmet Suat; Faculty Member; Department of Chemistry; College of Sciences; 178882N/A
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