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	Provedor de dados Nature Precedings (16) Autor Michael J. Bucknum (16) Eduardo A. Castro (11) Bin Wen (4) Doletha M. E. Szebenyi (1) E.A. Castro (1) Palavra-chave Chemistry (16) Earth & Environment (1) Tipo do documento Manuscript (16) Ano 2012 (1) 2011 (8) 2008 (7) País United Kingdom (16)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 16 Primeira ... 1 ... Última Lattice Parameters of Calcite in the PT-Plane to 7.62 Kb and 800 K Nature Precedings Michael J. Bucknum. Lattice parameters (a & c) of powdered, polycrystalline calcite in the trigonal-hexagonal system have been determined as a function of pressure and temperature using a hydrothermal diamond anvil cell (DAC), that has been separately described, and a synchrotron x-ray source. Diffraction data was collected using white synchrotron radiation in an energy dispersive technique (EDXRD). Temperature in the resistance heated hydrothermal DAC was measured by thermocouples to a maximum temperature of 800 K, and pressure was measured by the equation of state (EOS) of water, in which powdered calcite was immersed, to a maximum pressure of 7.62 Kb. The resulting study is an attempt to explore the potential of calcite as a double (P & T) internal x-ray... Tipo: Manuscript Palavras-chave: Chemistry; Earth & Environment. Ano: 2008 URL: http://precedings.nature.com/documents/1514/version/1 Chemical Topology of Crystalline Matter Nature Precedings Michael J. Bucknum. This work is intended as a review and extension of the seminal work in chemical topology developed by the crystallographer A.F. Wells in the 20th century. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2008 URL: http://precedings.nature.com/documents/1587/version/1 On the Hydrides of B, C, N, O and F Nature Precedings Michael J. Bucknum; Eduardo A. Castro. This paper reports a productive discussion of bonding principles in the non-metallic 2nd row hydrides. It suggests the inversion of a bonding character, potentially from hydrides of B & C, which may display unsaturation and electronic deficiency accompanied by electronic delocalization in 1D or 2D or 3D. Contrasted with the opposite possibility, within the finite number of hydrides of N, O and F, that display apparently extensive H-bonding and subsequently proton delocalization in 1D and 2D (in HF & ice polymorphs, respectively), and now potentially in 3D in a corresponding hydride of N called Rice's blue material, or perhaps polyimidogen. Where polyimidogen is a crystalline NH lattice that is a polymorph of the ammonium azide... Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/2541/version/2 Chemical Topology of Crystalline Matter and the Transcendental Numbers ϕ , e and π Nature Precedings Michael J. Bucknum; Eduardo A. Castro. This work is intended as a review and extension of the seminal work in chemical topology developed by the crystallographer A.F. Wells in the 20th century. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/1587/version/3 The carbon allotrope glitter as n-diamond and i-carbon nanocrystals Nature Precedings Michael J. Bucknum; Eduardo A. Castro. Diffraction data taken from nanocrystalline n-diamond and i-carbon forms is fit to a so-called glitter model, in which the geometry of the C lattice has been optimized by density functional theory (DFT). A calculated theoretical diffraction pattern for glitter is shown to be a close fit to the experimental data for these novel C forms. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/6489/version/2 Isoglitter Nature Precedings Michael J. Bucknum; Eduardo A. Castro; Bin Wen. Described herein is a novel crystalline pattern in space group Ammm, that is a model of a C allotrope. This so-called isoglitter structure-type is an analogue to the graphite-diamond hybrids. A DFT geometry optimization and band structure calculation indicates that the lattice is metallic in a C realization. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2012 URL: http://precedings.nature.com/documents/6483/version/3 Hypothetical Allotropes of Carbon Built from 1,4-Cyclohexadiene Rings Nature Precedings Michael J. Bucknum. Disclosure Document #337,466 filed with the U.S. Patent & Trademark Office on August 23, 1993 describes, for the first time in the published literature, certain hypothetical constructions known as 3-,4-connected networks built from 1,4-cyclohexadiene rings, as allotropes of carbon and binaries. These hypothetical structures include an allotrope of carbon of tetragonal symmetry (space group P4(2)/mmc) built entirely from 1,4-cyclohexadiene rings and called glitter, and an allotrope of carbon of orthorhombic symmetry (space group Pmmm) built entirely from 1,4-cyclohexadiene rings, as well, and given another name. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2008 URL: http://precedings.nature.com/documents/1530/version/1 Chemical Topology of Crystalline Matter and the Transcendental Numbers ϕ , e and π Nature Precedings Michael J. Bucknum; Eduardo A. Castro. This work is intended as a review and extension of the seminal work in chemical topology developed by the crystallographer A.F. Wells in the 20th century. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2008 URL: http://precedings.nature.com/documents/1587/version/2 Trigohexagonite: A Rare Quaternary Stoichiometry Network Nature Precedings Michael J. Bucknum; Bin Wen; Doletha M. E. Szebenyi; E.A. Castro. A rare quaternary stoichiometry network of high hexagonal symmetry (P-6m2) is described. A set of hexagonal fractional crystallographic coordinates, for both an idealized network, and optimized boron and carbon allotropic realizations are described along with their band structures. Both should be metallic phases. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2008 URL: http://precedings.nature.com/documents/1650/version/1 The carbon allotrope glitter as n-diamond and i-carbon nanocrystals Nature Precedings Michael J. Bucknum; Eduardo A. Castro. Diffraction data taken from nanocrystalline n-diamond and i-carbon forms is fit to a so-called glitter model, in which the geometry of the C lattice has been optimized by density functional theory (DFT). A calculated theoretical diffraction pattern for glitter is shown to be a close fit to the experimental data for these novel C forms. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/6489/version/1 Polymorphic (NH): As Polyimidogen and Ammonium Azide Structure-types Nature Precedings Michael J. Bucknum. This paper reports a productive discussion of bonding principles in the non-metallic 2nd row hydrides. It suggests the inversion of a bonding character, potentially from hydrides of B & C, which may display unsaturation and electronic deficiency accompanied by electronic delocalization in 1D or 2D or 3D. Contrasted with the opposite possibility, within the finite number of hydrides of N, O and F, that display apparently extensive H-bonding and subsequently proton delocalization in 1D and 2D (in HF & ice polymorphs, respectively), and now potentially in 3D in a corresponding hydride of N called Rice's blue material, or perhaps polyimidogen. Where polyimidogen is a crystalline NH lattice that is a polymorph of the ammonium azide... Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2008 URL: http://precedings.nature.com/documents/2541/version/1 On the Hydrides of B, C, N, O and F Nature Precedings Michael J. Bucknum; Eduardo A. Castro. This paper reports a productive discussion of bonding principles in the non-metallic 2nd row hydrides. It suggests the inversion of a bonding character, potentially from hydrides of B & C, which may display unsaturation and electronic deficiency accompanied by electronic delocalization in 1D or 2D or 3D. Contrasted with the opposite possibility, within the finite number of hydrides of N, O and F, that display apparently extensive H-bonding and subsequently proton delocalization in 1D and 2D (in HF & ice polymorphs, respectively), and now potentially in 3D in a corresponding hydride of N called Rice's blue material, or perhaps polyimidogen. Where polyimidogen is a crystalline NH lattice that is a polymorph of the ammonium azide... Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/2541/version/3 Geometrical-topological correlation in structures Nature Precedings Michael J. Bucknum; Eduardo A. Castro. The topology of polyhedra, tessellations and networks is described as to their mapping in Schlaefli space. A description of the topological form index is given and it is applied to these structural classes in terms of their geometries. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2008 URL: http://precedings.nature.com/documents/1651/version/1 Isoglitter Nature Precedings Michael J. Bucknum; Eduardo A. Castro; Bin Wen. Described herein is a novel crystalline pattern in space group Ammm, that is a model of a C allotrope. This so-called isoglitter structure-type is a model of a graphite-diamond hybrid. A DFT geometry optimization and band structure calculation indicates that the lattice is metallic in a C realization. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/6483/version/1 Preservation of C Hexagons in C Allotrope Transformations Nature Precedings Michael J. Bucknum; Eduardo A. Castro. In this Letter is described the analogous hexagon preserving C allotrope transformations of graphite to diamond, as a packing of C spheres on the one hand, and alternatively C nanotubes to the C allotrope hexagonite, as a packing of C cylinders on the other hand. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/6481/version/1 Isoglitter Nature Precedings Michael J. Bucknum; Eduardo A. Castro; Bin Wen. Described herein is a novel crystalline pattern in space group Ammm, that is a model of a C allotrope. This so-called isoglitter structure-type is a model of a graphite-diamond hybrid. A DFT geometry optimization and band structure calculation indicates that the lattice is metallic in a C realization. Tipo: Manuscript Palavras-chave: Chemistry. Ano: 2011 URL: http://precedings.nature.com/documents/6483/version/2 Registros recuperados: 16 Primeira ... 1 ... Última

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