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Inner elasticity and the higher-order elasticity of some diamond and graphite allotropesCousins, Christopher Stanley George January 2001 (has links)
No description available.
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Organic and organometallic compounds of the 1,3-dithiole-2-thione-4,5-dithiolate (dmit) ligandAllan, Gillian Margaret January 1999 (has links)
Neutral diorganotin compounds of the 1,3-dithiole-2-thione-4,5-dithiolate ligand have been prepared. The syntheses of Me<sub>2</sub>Sndmit, Et<sub>2</sub>Sndmit, Bu<sub>2</sub>Sndmit, (C<sub>8</sub>H<sub>17</sub>)<sub>2</sub>Sndmit, (C<sub>10</sub>H<sub>21</sub>)<sub>2</sub>Sndmit and (C<sub>14</sub>H<sub>29</sub>)<sub>2</sub>Sndmit are described. For the purposes of indicating the formation of different structural phases, D.S.C. powder patterns are reported for initial and recrystallised samples of Me<sub>2</sub>Sndmit, Et<sub>2</sub>Sndmit and Bu<sub>2</sub>Sndmit. Since Et<sub>2</sub>Sndmit<sub> </sub>showed different tin environments by solid phase state N.M.R. and clearly different powder patterns after recrystallisation, the compound was recrystallised from various solvents in an attempt to determine how many crystalline forms exist. To date, two forms have been identified: orthorhombic and monoclinic. The single crystal X-ray structure analyses of these are described. It has also been shown that upon heating a transition from the orthorhombic to the monoclinic form occurs at 140°C. The crystal strict of Me<sub>2</sub>Sndmit has also been determined and is reported, along with Mossbauer parameters for Me<sub>2</sub>Sndmit and Me<sub>2</sub>Sndmio (dmio = 1,3-dithiole-2-one-4,5-dithiolate). Anionic organotin bis-dmit complexes of the form [RSn(dmit)<sub>2</sub>][Q]<sup>+</sup> have also been prepared, with a view to investigating their electrochemical properties. The syntheses of complexes with R chain length ranging from 4 to 18 carbons are described. The problem of formation of [Sn(dmit)<sub>3</sub>][Q]<sub>2</sub> is also discussed. D.S.C. curves and cyclic voltammograms for [C<sub>14</sub>H<sub>29</sub>Sn(dmit)<sub>2</sub>][C<sub>14</sub>H<sub>29</sub>NMe<sub>3</sub>] and [NEt<sub>4</sub>][(dmit)<sub>2</sub>SnC<sub>10</sub>H<sub>20</sub>Sn(dmit)<sub>2</sub>][NEt<sub>4</sub>] are also described. Chiral macrocycles have potential uses as catalysts for asymmetric bond-forming reactions and as selective to metal ions. A chiral macrocyclic derivative of dmit was synthesised from methyl-4,6-<I>O</I>-benzylidene-2,3-bis-<I>O</I>-[(2-iodoethoxyethyl)-ethyl]-α-D-glucopyranoside. Since reaction of this with dmit proved to be unexpectedly problematic, attempted reactions of the sugar derivative with Na<sub>2</sub>dmit<I> in situ</I>, isolated Na<sub>2</sub>dmit, [Zn(dmit)<sub>2</sub>][NEt<sub>4</sub>]<sub>2</sub>, [Ph<sub>2</sub>Sn(dmit)I][NEt<sub>4</sub>] and Cs<sub>2</sub>dmit are described.
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Reticulados algébricos via corpos abelianosFerrari, Agnaldo José [UNESP] 22 February 2008 (has links) (PDF)
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ferrari_aj_me_sjrp.pdf: 927602 bytes, checksum: 80285856c8ad55e7993124cb6f12c22f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dado um ideal A do anel dos inteiros algébricos de um corpo de números, tem-se que a imagem deste ideal via o homomorfissmo de Minkowski é um reticulado no Rn, chamado de reticulado algébrico. Deste modo, o principal objetivo do presente trabalho é a construção de reticulados algébricos no Rn que sejam versões rotacionadas de reticulados conhecidos na literatura, e trabalhamos de modo particular até a dimensão 8. Além disso, vimos também reticulados obtidos via perturbações do homomorfismo de Minkowski. / We stablished that the image of an ideal A of the algebraic integer ring of a number field by the Minkowski homomorphism is a lattice in Rn, named algebraic lattice. In this way, the main goal of this work is the construction of algebraic lattices in Rn that be rotated versions of known lattices in the literature, and particularly we worked in dimensions up to 8. We also studied lattices obtained by perturbations of Minkowski homomorphism.
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Danos de radiacao em sulfato de calcioALBUQUERQUE, ANTONIO R.P.L. 09 October 2014 (has links)
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01257.pdf: 1883679 bytes, checksum: 16dcaa8a2de2f071f89d7e49a9912605 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Fisica, Universidade de Sao Paulo - IF/USP
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Reticulados algébricos via corpos abelianos /Ferrari, Agnaldo José. January 2008 (has links)
Orientador: Antonio Aparecido de Andrade / Banca: André Luiz Flores / Banca: Tatiana Bertoldi Carlos / Resumo: Dado um ideal A do anel dos inteiros algébricos de um corpo de números, tem-se que a imagem deste ideal via o homomorfissmo de Minkowski é um reticulado no Rn, chamado de reticulado algébrico. Deste modo, o principal objetivo do presente trabalho é a construção de reticulados algébricos no Rn que sejam versões rotacionadas de reticulados conhecidos na literatura, e trabalhamos de modo particular até a dimensão 8. Além disso, vimos também reticulados obtidos via perturbações do homomorfismo de Minkowski. / Abstract: We stablished that the image of an ideal A of the algebraic integer ring of a number field by the Minkowski homomorphism is a lattice in Rn, named algebraic lattice. In this way, the main goal of this work is the construction of algebraic lattices in Rn that be rotated versions of known lattices in the literature, and particularly we worked in dimensions up to 8. We also studied lattices obtained by perturbations of Minkowski homomorphism. / Mestre
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Danos de radiacao em sulfato de calcioALBUQUERQUE, ANTONIO R.P.L. 09 October 2014 (has links)
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01257.pdf: 1883679 bytes, checksum: 16dcaa8a2de2f071f89d7e49a9912605 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Fisica, Universidade de Sao Paulo - IF/USP
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Existence, Stability, and Dynamics of Solitary Waves in Nonlinear Schroedinger Models with Periodic PotentialsLaw, Kody John Hoffman 01 February 2010 (has links)
The focus of this dissertation is the existence, stability, and resulting dynamical evolution of localized stationary solutions to Nonlinear Schr¨odinger (NLS) equations with periodic confining potentials in 2(+1) dimensions. I will make predictions about these properties based on a discrete lattice model of coupled ordinary differential equations with the appropriate symmetry. The latter has been justified by Wannier function expansions in a so-called tight-binding approximation in the appropriate parametric regime. Numerical results for the full 2(+1)-D continuum model will be qualitatively compared with discrete model predictions as well as with nonlinear optics experiments in optically induced photonic lattices in photorefractive crystals. The predictions are also relevant for BECs (Bose-Einstein Condensates) in optical lattices.
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Geometry of numbers, class group statistics and free path lengthsHolmin, Samuel January 2015 (has links)
This thesis contains four papers, where the first two are in the area of geometry of numbers, the third is about class group statistics and the fourth is about free path lengths. A general theme throughout the thesis is lattice points and convex bodies. In Paper A we give an asymptotic expression for the number of integer matrices with primitive row vectors and a given nonzero determinant, such that the Euclidean matrix norm is less than a given large number. We also investigate the density of matrices with primitive rows in the space of matrices with a given determinant, and determine its asymptotics for large determinants. In Paper B we prove a sharp bound for the remainder term of the number of lattice points inside a ball, when averaging over a compact set of (not necessarily unimodular) lattices, in dimensions two and three. We also prove that such a bound cannot hold if one averages over the space of all lattices. In Paper C, we give a conjectural asymptotic formula for the number of imaginary quadratic fields with class number h, for any odd h, and a conjectural asymptotic formula for the number of imaginary quadratic fields with class group isomorphic to G, for any finite abelian p-group G where p is an odd prime. In support of our conjectures we have computed these quantities, assuming the generalized Riemann hypothesis and with the aid of a supercomputer, for all odd h up to a million and all abelian p-groups of order up to a million, thus producing a large list of “missing class groups.” The numerical evidence matches quite well with our conjectures. In Paper D, we consider the distribution of free path lengths, or the distance between consecutive bounces of random particles in a rectangular box. If each particle travels a distance R, then, as R → ∞ the free path lengths coincides with the distribution of the length of the intersection of a random line with the box (for a natural ensemble of random lines) and we determine the mean value of the path lengths. Moreover, we give an explicit formula for the probability density function in dimension two and three. In dimension two we also consider a closely related model where each particle is allowed to bounce N times, as N → ∞, and give an explicit formula for its probability density function. / <p>QC 20151204</p>
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Preparation of high-purity aluminum bicrystalsEvans, Herbert Elgin, 1962- January 1989 (has links)
The preparation of bicrystal specimens of high interfacial purity and accurately controlled mismatch of orientation between grains with a specific boundary orientation are critical for fundamental studies of the structure and properties of grain boundaries. A method was developed for routinely producing high-purity aluminum bicrystals of desired mismatch and boundary orientation. A strain annealing technique was used for making large single crystals. The orientation, structural perfection, and chemical purity of the seeds were characterized, then the seeds were joined by using an electron beam welder. The welder was designed and built as a major portion of this work.
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Modelling of dislocations in siliconValladares, Alexander January 1999 (has links)
No description available.
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