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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Report on the sixth blind test of organic crystal-structure prediction methods

Reilly, A.M., Cooper, R.I., Adjiman, C.S., Bhattacharya, S., Boese, D.A., Brandenburg, J.G., Bygrave, P.J., Bylsma, R., Campbell, J.E., Car, R., Case, D.H., Chadha, R., Cole, J.C., Cosburn, K., Cuppen, H.M., Curtis, F., Day, G.M., DiStasio, R.A. Jr, Dzyabchenko, A., van Eijck, B.P., Elking, D.M., van den Ende, J.A., Facelli, J.C., Ferraro, M.B., Fusti-Molnar, L., Gatsiou, C-A., Gee, T.S., de Gelder, R., Ghiringhelli, L.M., Goto, H., Grimme, S., Guo, R., Hofmann, D.W.M., Hoja, J., Hylton, R.K., Iuzzolino, L., Jankiewicz, W., de Jong, D.T., Kendrick, John, de Klerk, N.J.J., Ko, H-Y., Kuleshova, L.N., Li, X., Lohani, S., Leusen, Frank J.J., Lund, A.M., Lv, J., Ma, Y., Marom, N., Masunov, A.E., McCabe, P., McMahon, D.P., Meekes, H., Metz, M.P., Misquitta, A.J., Mohamed, S., Monserrat, B., Needs, R.J., Neumann, M.A., Nyman, J., Obata, S., Oberhofer, H., Oganov, A.R., Orendt, A.M., Pagola, G.I., Pantelides, C.C., Pickard, C.J., Podeszwa, R., Price, L.S., Price, S.L., Pulido, A., Read, M.G., Reuter, K., Schneider, E., Schober, C., Shields, G.P., Singh, P., Sugden, I.J., Szalewicz, K., Taylor, C.R., Tkatchenko, A., Tuckerman, M.E., Vacarro, F., Vasileiadis, M., Vazquez-Mayagoitia, A., Vogt, L., Wang, Y., Watson, R.E., de Wijs, G.A., Yang, J., Zhu, Q., Groom, C.R. 04 April 2016 (has links)
Yes / The sixth blind test of organic crystal-structure prediction (CSP) methods has been held, with five target systems: a small nearly rigid molecule, a polymorphic former drug candidate, a chloride salt hydrate, a co-crystal, and a bulky exible molecule. This blind test has seen substantial growth in the number of submissions, with the broad range of prediction methods giving a unique insight into the state of the art in the field. Significant progress has been seen in treating flexible molecules, usage of hierarchical approaches to ranking structures, the application of density-functional approximations, and the establishment of new workflows and best practices for performing CSP calculations. All of the targets, apart from a single potentially disordered Z0 = 2 polymorph of the drug candidate, were predicted by at least one submission. Despite many remaining challenges, it is clear that CSP methods are becoming more applicable to a wider range of real systems, including salts, hydrates and larger flexible molecules. The results also highlight the potential for CSP calculations to complement and augment experimental studies of organic solid forms. / EPSRC (grants EP/J01110X/1 and EP/K018132/1) and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC through grant agreements n. 307358 (ERC-stG- 2012-ANGLE) and n. 321156 (ERC-AG-PE5-ROBOT). The Russian Foundation (14-03-01091). GlaxoSmithKline, Merck, and Vertex. VIDI Research Program 700.10.427, which is financed by The Netherlands Organisation for Scientific Research (NWO), and the European Research Council (ERC-2010-StG, grant agreement n. 259510-KISMOL). Foundation for Fundamental Research on Matter (FOM). NSF grant number ACI-1053575. University of Buenos Aires and the Argentinian Research Council. Conflex Corp. and Ministry of Education, Culture, Sports, Science and Technology. Louisiana Board of Regents Award # LEQSF(2014-17)-RD-A-10 “Toward Crystal Engineering from First Principles”, the NSF award # EPS-1003897 “The Louisiana Alliance for Simulation-Guided Materials Applications (LA-SiGMA)”, and by the Tulane Committee on Research Summer Fellowship. Solar Technologies Go Hybrid initiative of the State of Bavaria, Germany. U.S. Department of Energy under contract DE-AC02-06CH11357. EPSRC (EP/J003840/1, EP/J014958/1) and [EP/J017639/1]. Leadership Fellowship Grant [EP/K013688/1]. Robinson College, Cambridge, and the Cambridge Philosophical Society for a Henslow Research Fellowship. Army Research Office under Grant W911NF-13-1- 0387 and by the National Science Foundation Grant CHE-1152899. Polish National Science Centre Grant No. DEC-2012/05/B/ST4/00086. EPSRC, though grant ESPRC EP/K039229/1, and Eli Lilly. The PhD students support: RKH by a joint UCL Max-Planck Society Magdeburg Impact studentship, REW by a UCL Impact studentship; LI by the Cambridge Crystallographic Data Centre and the M3S Centre for Doctoral Training (EPSRC EP/G036675/1). Army Research Office Grant W911NF-13-1-0387 and by the National Science Foundation Grant CHE-1152899. U.S. Army Research Laboratory and the U.S. Army Research Office under contract/grant number W911NF-13-1-0387 (MET and LV) and MRSEC program of the National Science Foundation under Award Number DMR-1420073 (MET and ES). U.S. Army Research Laboratory and the U.S. Army Research Office contract/grant number W911NF-13-1- 0387 and by the National Science Foundation Grant CHE-1152899. National Science Foundation (DMR-1231586), the Government of Russian Federation (Grant No. 14.A12.31.0003), the Foreign Talents Introduction and Academic Exchange Program (No. B08040) and the Russian Science Foundation, project no. 14-43-00052, base organization Photochemistry Center of the Russian Academy of Sciences. Army Research Office Grant W911NF-13-1-0387 and the National Science Foundation Grant CHE-1152899. Deutsche Forschungsgemeinschaft program DFG-SPP 1807. Department of Energy (DOE) Grant Nos. DE-SC0008626. Office of Science of the U.S. Department of Energy Contract No. DE-AC02-06CH11357. Office of Science of the U.S. Department of Energy contract No. DEAC02-05CH11231.
2

Exciton dynamics in tetracene single crystals studied using femtosecond laser spectroscopy

Birech, Zephania 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: See full text / AFRIKAANSE OPSOMMING: Sien volteks
3

Crescimento de cristais orgânicos e a avaliação de suas qualidades para aplicações em óptica não linear / Crystal growth and optical characterization of organic crystals with nonlinear optical properties

Moraes, Liana Bueno Oliveira Amorim de 10 August 1998 (has links)
Apresentamos os resultados de preparação e caracterização de cristais orgânicos (L-arginina fosfatada monohidratada - LAP - e L-lisina monohidroclorada dihidratada - L-Lys.HCl) que possuem propriedades ópticas lineares e não lineares desejáveis para aplicações tecnológicas, incluindo telecomunicações, computação óptica, armazenamento óptico de dados, processamento óptico da imagem, conversão de freqüência, entre outras. Desenvolvemos uma metodologia, simples e barata, para a eliminação de fungos e micróbios que surgem nas soluções destes compostos devido às características dos aminoácidos L-arginina e L-lisina. A adição do fungicida azida de sódio possibilitou-nos manter soluções destes compostos livres de quaisquer microorganismos na câmara de crescimento por um período de seis meses. Usando-se as técnicas de evaporação controlada do solvente a abaixamento da temperatura grandes cristais de LAP e L-Lys.HCl foram obtidos com qualidade óptica adequada para a confecção de dispositivos optoeletrônicos. Cristais de até 6 cm&sup3 de L-Lys.HCl foram pela primeira vez preparados e caracterizados opticamente. A caracterização estrutural permitiu-nos solucionar a divergência existente na indexação do difratograma de pó dos cristais de LAP e indexar os picos de difração de raios-X da L-lisina monohidroclorada dihidratada. / Growth and characterization of organic crystal (L-arginine phosphate monohydrate - LAP - and L-lysine monohydrochloride dihydrate L-Lys. HCl) with desirable linear and nonlinear optical properties for technological application including telecommunications, optical computing, optical data storage, optical image processing, harmonic frequency generation, and others are presented. We developed a simple and cheap method to eliminate fungi and microbes that arises in solution due to characteristics of L-arginine and L-lysine aminoacids. The addition of sodium azide fungicide maintained the solutions of these compounds free of microorganisms in the growth chamber for six months. Using a accurately controlled solvent evaporation technique and slow cooling technique large crystals of LAP and L-Lys.HCI were obtained with optical quality appropriate to the development of optoelectronic devices. L-Lys.HCl crystals up to 6 cm&sup3 were growth and optically characterized for the first time. The divergence in the powder diffraction indexation of LAP crystals was eliminated by structural characterization and the X-ray diffraction peaks of the L-lysine monohydrochloride diliydrate crystals were indexed.
4

Geracao de funcoes resposta de cintiladores organicos para neutrons rapidos, utilizando o metodo de Monte Carlo

MAZZARO, A.C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:50:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:03Z (GMT). No. of bitstreams: 1 00479.pdf: 1424196 bytes, checksum: 84b987bd53ea5391c5678d9c974e4bdf (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP
5

Crescimento de cristais orgânicos e a avaliação de suas qualidades para aplicações em óptica não linear / Crystal growth and optical characterization of organic crystals with nonlinear optical properties

Liana Bueno Oliveira Amorim de Moraes 10 August 1998 (has links)
Apresentamos os resultados de preparação e caracterização de cristais orgânicos (L-arginina fosfatada monohidratada - LAP - e L-lisina monohidroclorada dihidratada - L-Lys.HCl) que possuem propriedades ópticas lineares e não lineares desejáveis para aplicações tecnológicas, incluindo telecomunicações, computação óptica, armazenamento óptico de dados, processamento óptico da imagem, conversão de freqüência, entre outras. Desenvolvemos uma metodologia, simples e barata, para a eliminação de fungos e micróbios que surgem nas soluções destes compostos devido às características dos aminoácidos L-arginina e L-lisina. A adição do fungicida azida de sódio possibilitou-nos manter soluções destes compostos livres de quaisquer microorganismos na câmara de crescimento por um período de seis meses. Usando-se as técnicas de evaporação controlada do solvente a abaixamento da temperatura grandes cristais de LAP e L-Lys.HCl foram obtidos com qualidade óptica adequada para a confecção de dispositivos optoeletrônicos. Cristais de até 6 cm&sup3 de L-Lys.HCl foram pela primeira vez preparados e caracterizados opticamente. A caracterização estrutural permitiu-nos solucionar a divergência existente na indexação do difratograma de pó dos cristais de LAP e indexar os picos de difração de raios-X da L-lisina monohidroclorada dihidratada. / Growth and characterization of organic crystal (L-arginine phosphate monohydrate - LAP - and L-lysine monohydrochloride dihydrate L-Lys. HCl) with desirable linear and nonlinear optical properties for technological application including telecommunications, optical computing, optical data storage, optical image processing, harmonic frequency generation, and others are presented. We developed a simple and cheap method to eliminate fungi and microbes that arises in solution due to characteristics of L-arginine and L-lysine aminoacids. The addition of sodium azide fungicide maintained the solutions of these compounds free of microorganisms in the growth chamber for six months. Using a accurately controlled solvent evaporation technique and slow cooling technique large crystals of LAP and L-Lys.HCI were obtained with optical quality appropriate to the development of optoelectronic devices. L-Lys.HCl crystals up to 6 cm&sup3 were growth and optically characterized for the first time. The divergence in the powder diffraction indexation of LAP crystals was eliminated by structural characterization and the X-ray diffraction peaks of the L-lysine monohydrochloride diliydrate crystals were indexed.
6

Geracao de funcoes resposta de cintiladores organicos para neutrons rapidos, utilizando o metodo de Monte Carlo

MAZZARO, A.C. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:50:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:03Z (GMT). No. of bitstreams: 1 00479.pdf: 1424196 bytes, checksum: 84b987bd53ea5391c5678d9c974e4bdf (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP
7

X-ray crystal structure analyses of magnetically oriented microcrystalline suspensions / 磁場配向微結晶懸濁液を用いたX線結晶構造解析

Tsuboi, Chiaki 25 July 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19936号 / 農博第2186号 / 新制||農||1044(附属図書館) / 学位論文||H28||N5009(農学部図書室) / 33022 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 木村 恒久, 教授 西尾 嘉之, 教授 髙野 俊幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
8

Structural, Optical and Electrical Studies on Multi-Functional Organic Single Crystals

Saripalli, Ravi Kiran January 2017 (has links) (PDF)
In this thesis, the physical properties of certain multi-functional organic crystals were studied in detail. This study involves the growth of single crystals of Glucuronic acidγ-lactone (GAL), Imidazoliumtartarate (IMLT), (Bis)imidazoliumtartarate (BIMLT), and Diisopropylammonium iodide (DPI) and investigations of their optical, dielectric, piezoelectric, pyroelectric, and ferroelectric properties as a function of temperature and dependence on crystal structure in these organic crystals. Piezoelectric resonance was observed at certain frequencies when dielectric constant was monitored along the b-plate of GAL crystals. The electro-mechanical coupling coefficient estimated at the resonance near 1 MHz frequency revealed an exceptionally large value in GAL similar to that in inorganic lead titanate. The dependence of the piezoelectric resonance frequency on temperature was studied in detail. These crystals showed excellent second- and third-order nonlinear optical properties as well as high laser damage threshold. The high values of χ(2) andχ(3), laser damage threshold, and low UV cut-off makes GAL crystals an interesting prospect for NLO and laser applications. Towards this goal, GAL crystals were studied in detail with regard to determination of directions of dielectric axes, optic axes, and collinear phase-matching. Single crystals of another promising NLO organic crystal, IMLT were also grown which showed interesting dielectric, piezoelectric, and NLO properties. The dielectric dispersion with temperature provided an insight to the polarization mechanisms. Like GAL, IMLT also exhibits piezoelectric resonance. The existence of only one easy axis of vibration in IMLT enabled the candidate to identify the first resonance peak as corresponding to the fundamental mode of oscillation in the sample. This also helped to determine many piezoelectric parameters. By angular phase matching, one direction of phase matching in IMLT was identified. The conversion efficiency of IMLT along this direction was determined which was high in comparison to that in a standard KDP crystal. At piezoelectric resonance frequencies, the electro-optic response due to photo-elastic contributions is enhanced. Single crystals of organic ferroelectric BIMLT were grown by mixing two moles of imidazole with one mole of l-tartaric acid. The controversy with regard to the phase transition temperature of BIMLT was clarified by the DSC and structural analysis in this work. Previously, studies on BIMLT were limited to polycrystalline samples and single crystals with inclusions primarily due to the difficulty in growing good quality single crystals from aqueous solution. However, by experimenting the growth process using different solvents, good quality single crystals were achieved without the trapping of mother solution. This remarkable find is a notable result in these crystals for ferroelectric applications. The mechanism of ferroelectricity in BIMLT is mainly attributed to the transfer of protons along N–H---O hydrogen bonds in the direction of b-axis. Interestingly, the values of spontaneous polarization and Curie-temperature in the organic ferroelectric material DPI were significantly high and comparable to several popular inorganic ferroelectrics. The polarization obtained in this material is the highest among reported organic ferroelectrics. In addition to the high Curie temperature and spontaneous polarization, there were unique phase transitions that were revealed in DPI. The mechanism of ferroelectricity is quite complex, mainly being displacive type on account of the change in orientation of dipoles with electric field. Some contribution to ferroelectricity comes from the order-disorder nature of Nitrogen atom.
9

Structural and spectroscopical study of crystals of 1,3,4-oxadiazole derivatives at high pressure

Franco González, Olga January 2002 (has links)
Die Suche nach neuen Materialien von technischem Interesse hat in den letzten Jahren neue Antriebe zu der Untersuchung organischer Verbindungen gegeben. Organische Substanzen haben viele Vorteile wie z.B. die Möglichkeit, ihre Eigenschaften durch verschiedene chemische und physikalische Techniken im Herstellung-Prozess für ein bestimmtes Ziel zu modifizieren. Oxadiazolverbindungen sind interessant aufgrund ihrer Nutzung als Material für Licht emittierende Dioden und Scintillatoren. <br /> <br /> Die physikalischen Eigenschaften eines Festkörpers hängen von seiner Struktur ab. Unterschiedliche Strukturen entwickeln unterschiedliche intra- und intermolekülare Wechselwirkungen. Eine ausgezeichnete Weise, um sowohl die intra- als auch die intermolekularen Wechselwirkungen eines bestimmtes Stoffes zu beeinflussen, ohne seine chemischen Charakteristiken zu ändern, ist die Verwendung von hohem Druck. <br /> <br /> Wir haben den Einfluss von hohem Druck und hoher Temperatur auf die super-molekulare Struktur einiger Oxadiazolverbindungen im kristallinem Zustand untersucht. Aus diesen Untersuchungsergebnissen wurde eine Zustandsgleichung für diese Kristalle bestimmt. Überdies wurden die spektroskopischen Eigenschaften dieser Materialien unter hohem Druck charakterisiert. / In recent years the search for new materials of technological interest has given new impulses to the study of organic compounds. Organic substances possess a great number of advantages such as the possibility to adjust their properties for a given purpose by different chemical and physical techniques in the preparation process. Oxadiazole derivatives are interesting due to their use as material for light emitting diodes (LED) as well as scintillators. <br /> <br /> The physical properties of a solid depend on its structure. Different structures induce different intra- and intermolecular interactions. An advantageous method to modify the intra- as well as the intermolecular interactions of a given substance is the application of high pressure. Furthermore, using this method the chemical features of the compound are not influenced.<br /> <br /> We have investigated the influence of high pressure and high temperature on the super-molecular structure of several oxadiazole derivatives in crystalline state. From the results of this investigation an equation of state for these crystals was determined. Furthermore, the spectroscopical features of these materials under high pressure were characterized.

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