Molecular Geometry
Mostrando 13-24 de 193 artigos, teses e dissertações.
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13. Explorando as percepções de professores em serviço sobre as visualizações no ensino de química
Taking into account the requirements for the teaching of chemistry, several visualization resources (software, videos, animations, molecular models, among others) are available. These visual aids are used in order to enhance the understanding of chemical phenomena in the classroom. However, many teachers make scant use of these resources, limiting macroscopi
Quím. Nova. Publicado em: 2013
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14. A Theoretical investigation of a potential high energy density compound 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo[3.1.1.1(2,4)]octane
The B3LYP/6-31G (d) density functional theory (DFT) method was used to study molecular geometry, electronic structure, infrared spectrum (IR) and thermodynamic properties. Heat of formation (HOF) and calculated density were estimated to evaluate detonation properties using Kamlet-Jacobs equations. Thermal stability of 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tric
Quím. Nova. Publicado em: 2013
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15. Estudo de propriedades petrofísicas de rochas sedimentares por Ressonância Magnética Nuclear / Petrophysical properties study of sedimentary rocks by Nuclear Magnetic Resonance
The Nuclear Magnetic Resonance (NMR) technique is one of the most versatile techniques for scientific research, specially for the study of dynamics, structure and conformational of materials. In particular, its application in oil science is one of its first routine applications. Methodologies developed specifically to match this scientific community proved t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/05/2012
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16. SYNTHESIS,CHARACTERIZATION AND THEORETICAL STUDY OF ORTHO-SUBSTITUTED SCHIFF BASES AND THEIR COPPER(II) COMPLEXES AS POTENTIAL ANTITUMOR AGENTS / SÍNTESE, CARACTERIZAÇÃO E ESTUDO TEÓRICO DE BASES DE SCHIFF ORTO-SUBSTITUÍDAS E SEUS COMPLEXOS DE COBRE(II) COMO POTENCIAIS AGENTES ANTITUMORAIS
Nowadays, the neoplastic processes have been one of the most concern diseases. The malignance tumor, also called cancer, is the most aggravating pathological process, responsible for the death of the patient in most cases. In this context, several drugs have been designed with the objective to eliminate the cancer cells selectively; among them, some coordina
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/02/2012
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17. Ferramenta de auxílio no processo ensino-aprendizagem: eficácia da utilização de kit educacional no primeiro ano do ensino médio na disciplina de química
Uma das dificuldades encontradas no ensino da Química é o estabelecimento de relações entre representações do nível microscópico e as do macroscópico na exploração de um conceito. Estudos anteriores mostraram que a utilização de ferramentas de visualização computacional ou física resulta em aprendizado mais efetivo de conceitos. Acredita-se q
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/02/2011
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18. Uso de modelagem molecular no estudo dos conceitos de nucleofilicidade e basicidade
Molecular modeling enables the students to visualize the abstract relationships underlying theoretical concepts that explain experimental data on the molecular and atomic levels. With this aim we used the free software "Arguslab 4.0.1" (semi-empirical method) to study the reaction of 1-chloropropane with ethoxide in solution, known to lead to methyl propyl e
Química Nova. Publicado em: 2011-09
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19. Comparative study of BxNyCz nanojunctions fragments
Theoretical analysis of formation energy and geometry was done to compare the relative stabilities of modified carbon nanostructures representative fragments. Structure and energies of formation were calculated at semiempirical level of theory. Depending of B-N pair localization on the molecular structures the formation enthalpy decreases. B-N substitution i
Materials Research. Publicado em: 12/08/2011
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20. STUDY OF BINARY COMPLEXES OF ALUMINUM(III) WITH SULFUR AMINO ACIDS AND PHOSPHATE LIGANDS / ESTUDO DE COMPLEXOS BINÁRIOS DE ALUMÍNIO(III) COM AMINOÁCIDOS SULFURADOS E LIGANTES FOSFATADOS
The study of binary complexes of Al(III) with sulfur amino acids (methionine, cysteine, homocysteine and penicillamine) and phosphate ligands (adenosine 5 - triphosphate and phosphocreatine) was done in aqueous solution applying potentiometric titrations, (13)C and (27)Al NMR, Raman spectroscopy, molecular modeling and DFT: B3LYP/6-311G theoretical calculati
Publicado em: 2010
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21. A Realidade Virtual como uma ferramenta para o ensino da Geometria Molecular
Hoje cada vez mais o acesso ao uso da Informática como apoio as ações e tarefas humanas é extremamente difundido nas escolas, nas residências, nas empresas e em outras diversas aplicações. Especificamente, na Educação a utilização da Informática como ferramenta de apoio ao professor e aos alunos tem sido foco de muitos trabalhos desenvolvidos pel
Publicado em: 2010
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22. Crescimento de nanofios auto-sustentados de arseneto de índio por epitaxia por feixes moleculares
This Thesis reports the experimental and theoretical works related to the growth and characterization of free-standing gallium indium arsenide nanowires grown by Molecular Beam Epitaxy (MBE). The growth mechanisms of free-standing nanowires remain barely known and explored in its fundamental aspects. The theoretical models of the formation of free-standing n
Publicado em: 2010
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23. ESTUDO TEÓRICO DE ESTRUTURA, PROPRIEDADES E REATIVIDADE DE TRIGLICERÍDEOS E ÉSTERES DE ÁCIDOS GRAXOS ENVOLVIDOS NA PRODUÇÃO E COMPOSIÇÃO DO BIODIESEL
The present work aims the study of structural and thermodynamic properties for process involving triglycerides (TG), fatty acid esters (EAG) and biodiesel through theoretical and chemometrical methodologies. The study of the transesterification reaction of triglycerides (TG) using cyclodextrin (CD) as a potential catalyst were also carried out. Initially, th
Publicado em: 2010
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24. Processos litográficos em filmes epitaxiais de compostos IV-VI para medidas Hall e o estudo da dopagem do telureto de chumbo com flureto de bário / Lithographic processes in epitaxial films of IV-VI compounds for Hall measurements and the study of lead telluride doping with barium flouride
The first part of the work dealt with the application of lithographical techniques to fabricate Hall geometry of IV-VI films grown on (111) BaF_2 substrates. A previous study of In diffusion in PbTe films confirmed the viability of using In as a metallic contact. During the lithographic process, some solutions were implemented to resolve the problems generat
Publicado em: 2009