42,391 research outputs found
Ba6P12N17O9Br3 - A Column-Type Phosphate Structure Solved from Single-Nanocrystal Data Obtained by Automated Electron Diffraction Tomography
No full textOxonitridophosphate Ba6P12N17O9Br3 was synthesized by heating a multicomponent mixture of BaBr2, BaS, phosphoryl triamide and thiophosphoryl triamide in an evacuated and sealed silica-glass ampoule to 750 degrees C. Ba6P12N17O9Br3 was obtained as the main product as a nanocrystalline powder. The crystal structure was determined ab initio on the basis of electron diffraction data acquired from a single needle-shaped nanocrystal by automated diffraction tomography. Ba6P12N17O9Br3 crystallizes in the hexagonal space group P6(3)/m (no. 176) with unit cell parameters alpha = 14.654(19), c = 8.255(9) angstrom and Z = 2. Its structure includes triangular, column-shaped anions of (1)(infinity){(P12N17O9)(9-)}, which are built from vertex-sharing P(O,N)(4) tetrahedra with 3-rings and three-coordinate nitrogen atoms. The 1D anions are separated by Ba2+ and Br- ions, which are arranged in channels parallel to the phosphate anions along [001]. The Ba2+ ions are eight- and nine-coordinated by Br- and O/N atoms, respectively. RI Kolb, Ute/A-2642-2011; Mugnaioli, Enrico/E-6237-2011; Sedlmaier, Stefan/K-6868-201
SrP3N5O: A Highly Condensed Layer Phosphate Structure Solved from a Nanocrystal by Automated Electron Diffraction Tomography
No full textThe oxonitridophosphate SrP3N5O has been synthesized by heating a multicomponent reactant mixture that consisted of phosphoryl triamide OP(NH2)(3), thiophosphoryl triamide SP(NH2)(3), SrS, and NH4Cl enclosed in evacuated and sealed silica-glass ampoules up to 750 degrees C. The compound was obtained as nanocrystalline powder with needle-shaped crystallites. The crystal structure was solved ab initio on the basis of electron diffraction data by means of automated electron diffraction tomography (ADT) and verified by Rietveld refinement with X-ray powder diffraction data. SrP3N5O crystallizes in the orthorhombic space group Pnma (no. 62) with unit-cell data of a = 18.331(2), b = 8.086(1), c = 13.851(1) angstrom and Z = 16. The compound is a highly condensed layer phosphate with a degree of condensation kappa = 1/2. The corrugated layers (2)(infinity){(P3N5O)(2-)} consist of linked, triangular columns built up from P(O, N)(4) tetrahedra with 3-rings and triply binding nitrogen atoms. The Sr2+ ions are located between the layers and exhibit six-, eight-, and ninefold coordination. FTIR and solid-state NMR spectra of SrP3N5O are discussed as well. RI Mugnaioli, Enrico/E-6237-2011; Kolb, Ute/A-2642-2011; Sedlmaier, Stefan/K-6868-201
Integralismo, Círculo Operário Católico e sindicatos em Joinville (1931-1948)
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Programa de Pós-Graduação em História, Florianópolis, 2011Neste trabalho proponho analisar as relações que envolveram três entidades de Joinville entre os anos de 1931 a 1948, quais sejam: Integralismo, Círculo Operário Católico e Sindicatos. Pretendo investigar as ações dessas entidades e a trajetória de suas lideranças: Aristides Largura, padre Alberto Kolb e Conrado de Mira respectivamente, na tentativa de entender quais as motivações que levaram à surpreendente união desses três personagens, em 1945, para fundar o Partido Trabalhista Brasileiro (PTB) na cidade. Um dos pontos de partida do trabalho é a desconfiança sobre a teoria da etnicidade como principal explicação para o sucesso integralista em Joinville. Outro questionamento é sobre as ações de padre Kolb e suas atividades políticas. O sindicalista Conrado de Mira, por sua vez, soube rapidamente compreender o funcionamento do aparelho sindical e utilizou-se disso para projetar sua carreira política na cidade.The aim of this work is to analyze the relationships that involved three entities of the city of Joinville between the years 1931 to 1948, which are: Integralism, Catholic Worker#s Circle and Unions. I intend to investigate the actions of these entities and the path of their leaders: Aristides Largura, priest Alberto Kolb and Conrado de Mira respectively, attempting to understand the motivations that in 1945 surprisingly provided the union of these three characters to found the entourage Partido Trabalhista Brasileiro (PTB) in the city. One of the bases of this work is the suspicion about the theory of ethnicity as the main explication for the integralist success in Joinville. Another questioning is about priest Kolb#s actions and his political activities. The syndicalist Conrado de Mira, in turn, quickly recognized the running of the trade union apparatus and used that to project his political career in the city
Edward Kolb: Einstein's Cosmic Legacy
No full textPublic Lecture im Rahmen des 2nd Vienna Central European Seminar on Particle Physics and Quantum Field Theory
Mitschnitt einer Veranstaltung am Freitag, dem 25. November 2005 im Großen Hörsaal des Instituts für Experimentalphysik der Universität Wien
Moderation: Helmuth Hüffel
Edward W. Kolb ist Professor für Astronomie und Astrophysik an der Universität Chicago sowie Leiter des Particle Astrophysics Center am Fermi National Accelerator Laboratory in Batavia, Illinois.
Eine Video-Aufzeichnung der Österreichischen Zentralbibliothek für Physik
Inhalt: 1. Introduction [00:00:00],
2. Space and Time [00:05:02],
3. Einstein’s Cosmology [00:08:50],
4. Dark Energy [00:12:41],
5. Cosmic Legacy [00:17:45],
6. Universe of Galaxies [00:23:51],
7. Cosmic Seeds [00:29:34],
8. Schrödinger [00:33:08],
9. Composition of the Universe [00:39:00],
10. Quantum Vacuum [00:46:39],
11. Every Cubic Inch... [00:50:07],
12. Primordial Soup [00:55:26],
13. Discussion [01:02:47
Charoite, as an example of a structure with natural nanotubes
No full textCharoite from the Murun massif in Yakutiya, Russia (Vorob'ev 2008) was investigated using automated electron diffraction tomography (ADT) (Kolb et al. 2007, 2008; Mugnaioli et al. 2010) and precession electron diffraction (PED) (Mugnaioli et al. 2010, 2009), which allowed to determine the structure of charoite for the first time. The structure was solved ab initio in space group P21/m by direct methods using a fully kinematic approach. The least squares refinements with 2878 reflections F(hkl) >4sF converged to unweighted/weighted residuals R1/wR2 • 0.173/0.21 (Rozhdestvenskaya et al. 2010). © 2012 Springer-Verlag Berlin Heidelberg. All rights are reserved
Structure analysis of titanate nanorods by automated electron diffraction tomography
No full textA hitherto unknown phase of sodium titanate, NaTi3O6(OH)center dot 2H(2)O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)center dot 2H(2)O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically affected by pervasive defects, such as mutual layer shifts, that produce diffraction streaks along c*. In addition, edge dislocations were observed in HRTEM images. RI Tremel, Wolfgang/D-8125-2011; Andrusenko, Iryna/E-6239-2011; Mugnaioli, Enrico/E-6237-2011; Kolb, Ute/A-2642-201
Synthesis of Fullerene- and Nanotube-Like SnS2 Nanoparticles and Sn/S/Carbon Nanocomposites
No full textSnS2 nested fullerene-type (IF) nanoparticles, nanotubes, and SnS2/C hybrid nanostructures were obtained by vapor transport starting from elemental tin and CS2. The reaction was carried out in a single-step process by heating elemental tin metal powder in a horizontal tube furnace at 800-1000 degrees C. TEM analysis allowed proposing a plausible mechanism for the formation of fullerene-like particles of SnS2 as well as tubes and scrolls from nanosheets of SnS2. Pure material could be obtained by optimizing the reaction based on a product analysis using powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) combined with energy-dispersive X-ray spectroscopy (EDX). RI Kolb, Ute/A-2642-2011; Tremel, Wolfgang/D-8125-2011; Mugnaioli, Enrico/E-6237-201
Asymmetric tungsten oxide nanobrushes via oriented attachment and Ostwald ripening
No full textTungsten oxide nanobrushes were synthesized using a solvothermal approach that lead to self-branching in the presence of citric acid and hexadecylamine as surfactants. Our synthetic approach yielded branched nanorods of tungsten oxide in a single synthetic step. Based on our results, we propose a phenomenological pathway for the formation, branching, and assembly of these tungsten oxide brushes. The formation of tungsten oxide brushes proceeds by thermal decomposition of ammonium tungstate in the presence of citric acid and hexadecylamine. The pale blue powder obtained after solvothermal reaction was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The field emission (FE) properties of the tungsten oxide nanostructures which can be tailored by their aspect ratio and the hierarchical nanostructures follow a Fowler-Nordheim behavior. RI Tremel, Wolfgang/D-8125-2011; Mugnaioli, Enrico/E-6237-2011; Kolb, Ute/A-2642-2011; GOLBERG, Dmitri/H-2776-201
Synthesis of Hierarchically Grown ZnO@NT-WS2 Nanocomposites
No full textA chemically specific and facile method for growth of ZnO nanorods on WS2 nanotubes (NT-WS2) is reported. The modification strategy is based on the chalcophilic affinity of Zn, which serves as an anchor to immobilize ZnO colloids onto the WS2 nanotubes. The surface bound ZnO colloids have been used as a seed to grow ZnO nanorods on WS2 nanotubes. The immobilization of ZnO colloids was monitored by UV-vis spectroscopy and photoluminescence spectroscopy whereas the growth of ZnO nanorods was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RI Kolb, Ute/A-2642-2011; tahir, Muhammad Nawaz/B-7650-2011; Tremel, Wolfgang/D-8125-2011; Mugnaioli, Enrico/E-6237-201
Essential features of the polytypic charoite-96 structure compared to charoite-90
No full textCharoite, ideally (K,Sr,Ba,Mn)(15-16)(Ca,Na)(32)[(Si(70)(O,OH)(180))](OH,F)(4)center dot nH(2)O, is a rock-forming mineral from the Murun massif in Yakutia, Sakha Republic, Siberia, Russia, where it occurs in a unique alkaline intrusion. Charoite occurs as four different polytypes, which are commonly intergrown in nanocrystalline fibres. We report the structure of charoite-96 (a = 32.11(6), b = 19.77(4), c = 7.23(1) angstrom, beta = 95.85(9)degrees, V = 4565(24) angstrom(3), space group P2(1)/m), which was solved ab initio by direct methods on the basis of 2676 unique electron diffraction reflections collected by automated diffraction tomography and refined to R(1)/wR(2) = 0.34/0.37. The structure of charoite-96 is related to that of the charoite-90, which was also solved recently. Both structures are composed of three different types of dreier silicate chains running along [001] and separated by ribbons of edge-sharing Ca- and Na-centred octahedra. In the structure of charoite-96, adjacent blocks formed by three different silicate chains and stacked along the x axis, are shifted by a translation of 1/2 e. The shifts involve a hybrid dreier quadruple chain, [Si(17)O(43)](18-) and a double dreier chain, [Si(6)O(17)](10-). In charoite-90 adjacent blocks are stacked without shifts. RI Mugnaioli, Enrico/E-6237-2011; Kolb, Ute/A-2642-201
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