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Ciências Exatas e da Terra.

Moscati, Giorgio; Lerner, Eugênio
Fonte: CNPq/Coordenação Editorial; Brasília Publicador: CNPq/Coordenação Editorial; Brasília
Tipo: Parte de Livro
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O III PBDCT foi elaborado como um roteiro para a atuação do governo na área de ciência e tecnologia para o período de 80/85 e representa o detalhamento do capítulo IV do III PND. Dentro desse enquadramento, é feita a seleção de programas e atividades prioritárias, cuja implementação se consubstancia através de Ações Programadas em Ciência e Tecnologia, sob a coordenação do CNPq e com a participação dos setores interessados. O documento de Avaliação & Perspectivas das diversas subáreas se constitue em trabalho critico e comparativo entre o que propõe o PBDCT e o resultado das Ações Programadas, além de fornecer os elementos para as correções e para a definição dos novos rumos a serem seguidos. Este documento é composto da Avaliação e Perspectivas nas seguintes subáreas: Astronomia, Computação, Estatística, Física, Geociências, Matemática, Oceanografia e Química. Os redatores das subáreas foram convidados seguindo-se indicação dos respectivos Comitês Assessores, ficando assim constituída a equipe responsável pelo documento na Área de Ciências Exatas e da Terra: Professor Eugênio Lerner (coordenador) Astronomia - professor Edemundo da Rocha Vieira (UFRGS) Computação- professor Ysmar Viana e Silva Filho (UFRJ) Estatística- professor Djalma Galvão Carneiro Pessoa (IMPA) Física- professor Roberto Leal Lobo e Silva (CBPF) Geociências - professor Irajá Damiani Pinto (UFRGS) Matemática - professor Carlos Augusto Isnard (IMPA) Oceanografia - professor Clovis Teixeira (USP) Química- professor Walter Baptista Mors (UFRJ) Aos redatores foram dados meios para convidarem um certo número de pessoas da comunidade que os pudessem assessorar nos diversos setores de suas subáreas. Na preparação dos documentos os redatores se valeram...

Introdução às Ciências Exatas e da Terra.

Moscati, Giorgio
Fonte: CNPq; Brasília Publicador: CNPq; Brasília
Tipo: Parte de Livro
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O III PBDCT foi elaborado como um roteiro para a atuação do governo na área de ciência e tecnologia para o período de 80/85 e representa o detalhamento do capítulo IV do III PND. Dentro desse enquadramento, é feita a seleção de programas e atividades prioritárias, cuja implementação se consubstancia através de Ações Programadas em Ciência e Tecnologia, sob a coordenação do CNPq e com a participação dos setores interessados. O documento de Avaliação & Perspectivas das diversas subáreas se constitui em trabalho crítico e comparativo entre o que propõe o PBDCT e o resultado das Ações Programadas, além de fornecer os elementos para as correções e para a definição dos novos rumos a serem seguidos. Este documento é composto da Avaliação e Perspectivas nas seguintes subáreas: Astronomia, Computação, Estatística, Física, Geociências, Matemática, Oceanografia e Química. Os redatores das subáreas foram convidados seguindo-se indicação dos respectivos Comitês Assessores, ficando assim constituída a equipe responsável pelo documento na Área de Ciências Exatas e da Terra: Professor Eugênio Lerner - Coordenador (UFRJ) Astronomia - professor Edemundo da Rocha Vieira (UFRGS) Computação - professor Ysmar Vianna e Silva Filho (UFRJ) Estatística - professor Djalma Galvão Carneiro Pessoa (IMPA) Física - professor Roberto Leal Lobo e Silva Filho (CBPF) Geociências- professor Irajá Damiani Pinto (UFRGS) Matemática- professor Carlos Augusto lsnard (IMPA) Oceanografia - professor Clovis Teixeira ( USP) Química- professor Walter Baptist Mors (UFRJ) Aos redatores foram dados meios para convidarem um certo número de pessoas da comunidade que os pudessem assessorar nos diversos setores de suas subáreas. Na preparação dos documentos os redatores se valeram...

O processo de implantação do curso de licenciatura em Física a distância pela universidade aberta do Brasil na Universidade Federal de Goiás no polo de apoio presencial em Goianésia - GO na visão de seus gestores; The process of implantation the degree course in distance physics by open University of Brazil in the University Federal of Goiás at the polo of support presencial in Goianésia - GO on vision of its managers

ELIAS, Abdalla Antonios Kayed
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Educação em Ciências e Matemática; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Educação em Ciências e Matemática; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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This paper presents the model of management degree in Physics Course by Distance Learning Open University of Brazil at the Federal University of Goiás in support pole in Goianésia - GO in view of its managers. The aim of this study is to analyze the conditions deployment and management degree in Physics course by distance learning System UAB in UFG, the pole in Goianésia - GO, from the perspective of their managers, with the intention of contribute to the development of this teaching modality. In this sense it became necessary to establish specific objectives, answer some questions that guided the development of the work, namely: How distance education was formed in UFG? What is your vision and managers on the course by distance? In an attempt to answer these questions and achieve the main objective, we analyzed throughout the paper, the following aspects related to the course, in view of their managers: 1. the implementation of the course; 2. the Educational Project Course, 3 . the administrative management; 4. the academic staff; 5. the learning process; 6. the assessment of learning; 7. the teaching material. The methodology used in this work was a case study with a qualitative approach, considered here for the most appropriate approach to the object. This work is composed of four chapters. The first presents some views on the course by distance and a brief history of the formation process of distance education in Brazil. In the second...

Efeitos da correlação eletrônica sobre as polarizabilidades longitudinais do polidifluoroacetileno; Effects of electron correlation on the polarizabilities longitudinal polidifluoroacetileno

TORRES, Elber Magalhães
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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This work presents ab initio results, including correlation corrections, for the static longitudinal linear polarizability, ®L, and longitudinal second hyperpolarizability, °L, of planar and twisted fluorinated polyacetylene (polyacetylene) chains. These electric properties were calculated by the finite field (FF) method and the correlated energies were obtained by means of the second order MÁller-Plesset perturbation theory (MP2). Our MP2 calculations were performed using the 6-31G basis set, although the geometry optimization involved both, the 6-31G and 6-31G(d) basis sets. Our results show that the incorporation the electron of correlation effects in the calculations of the polarizabilities, specially the hyperpolarizabilities, is essencial in order to obtain reliable estimates of these properties. Our estimates also demonstrate that the substitution of the H atoms in polyacetylene by F atoms, a procedure that gives rise to polydifluoroacetylene (PDFA), has the effect of incrasing the non-linear response of this material.; Neste trabalho apresentamos resultados ab initio, incluindo a correlação eletrônica, para a polarizabilidade linear longitudinal, ®L, e segunda hiperpolarizabilidade longitudinal, °L, de cadeias planares e helicoidais de poliacetileno fluoretadas (polidifluoroacetileno). Estas propriedades elétricas foram calculadas por meio do campo finito (FF) e as energias correlacionadas foram obtidas por meio da teoria de perturbação de MÁller-Plesset de segunda ordem (MP2). Nossos cálculos MP2 foram feitos usando o conjunto base 6-31G...

Estudo das propriedades magnéticas das ferritas ZnxMg1- xFe2O4 sintetizadas pelo método da reação de combustão; Study of magnetic properties of ferrite-ZnxMg1 xFe2O4 synthesized by the method of combustion reaction

SILVA, Marcelo dos Santos
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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The ferrites have been studied systematically, due to their dielectric and magnetic properties, being used in various applications in industry such as core processors, catalysts. In this work, we synthesized and characterized ferrites ZNXMg(1-x) Fe2O4, where 0≤x≤0.8, by the method of combustion reaction. This method have been used to produce ferrites quickly and inexpensively for producing ferrites quickly and inexpensively. The following chemical were used in the synthesis: iron nitrate Fe(NO3)3.9H2O, magnesium nitrate Mg (NO3)3.6H2O, zinc nitrate Zn(NO3)3.6H2O and urea CO(NH2)2 as fuel. The obtained ferrites were analysed by atomic absorption spectroscopy, X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) and vibrating sample magnetometer (VSM). The results of atomic absorption spectroscopy showed that the samples were synthesized with stoichiometry close to the calculated. The Xray diffraction showed that there was the formation of the spinel phase, typical of ferrites, the crystallite size varied from 37nm to x = 0.8 and 55 nm for x = 0.4. Infrared spectroscopy showed absorption bands typical of spinel type ferrites. The magnetic saturation, coercivity and remanent magnetization varied with the amount of zinc. The x=0...

Operador Deslocamento Condicional: Geração de Estados e Medida da Função de Wigner; Conditional Operator Shift: Generation of states and the Wigner Function Measure

SOUZA, Simone Ferreira
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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We present a feasible proposal for the construction of the conditional displacement operator using a Kerr medium between two beam splitters fed from coherent states highly excited. The device allows the implementation of the generation of a new class of states the quantized electromagnetic field (arbitrary superpositions of states with states moved) and the measurement of the Wigner function for arbitrary states. The application special case of the number of states and study their nonclassical properties were also considered.; Apresentamos uma proposta factível para a construção do operador deslocamento condicional usando um meio Kerr entre dois divisores de feixes alimentados por estados coerentes altamente excitados. O dispositivo permite implementar a geração de uma nova classe de estados do campo eletromagnético quantizado (superposições de estados arbitrários com estados deslocados) bem como a medição da função de Wigner para estados arbitrários. A aplicação especial ao caso de estados de número e o estudo de suas propriedades não-clássicas, foram também consideradas.

Efeitos de solvente sobre propriedades elétricas de compostos mesoiônicos; Solvent effects on electrical properties of mesoionic compounds

SANTOS, Orlei Luiz dos
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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In this work we study the electric properties of mesoionic compounds in the gaseous phase in different solvents, with a special attention to the first hyperpolarizability (β ). The Hartree-Fock (HF) method and the second-order Møller Plesset perturbation theory (MP2) were used to describe the electronic structure. The solvent effects were modelled using the selfconsistent reaction field approach with the Polarizable Continuum Model (PCM) and the electric properties were calculated numerically with the finite field method and analytically with the coupled perturbed Hartree-Fock (CPHF) procedure. The results obtained show the importance of inclusion of the solvent effects with significant alteration in the values of the electric properties as compared with the results in the gaseous phase. Nevertheless, such properties are almost not affected by changes in the solvent polarity. Comparisons between the HF and MP2 results indicate that the first hyperpolarizability is particularly sensitive to the inclusion of the electron correlation effects. In addition, a substantial increase in the β values is observed with the incorporation of a strong electron acceptor group.; Neste trabalho estudamos as propriedades elétricas de compostos mesoiônicos em fase gasosa e em diferentes solventes...

Estudos da sinterização de Bi12TiO20 (BTO) visando obter cerâmicas transparentes; Studies of sintering Bi12TiO20 (BTO) in order obtain transparent ceramics

AMARAL, Thiago Martins
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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This work presents the systematic results of studies concerning the sintering of the Bi12TiO20 (BTO) aiming the production of transparent ceramic samples. All that because the BTO is a material that has great scientific and technologic visibility due to its optical, electro and electro-optical properties, but still little explored as ceramic. The sintering starting material was obtained by solid state reaction between Bi2O3 e TiO2; the synthesized BTO was grinded in ball milling until sub micrometric sizes. The conditions for preparing green samples were also investigated, allowing samples with green relative density between 58% and 62%, with uniaxial and isostatic pressing techniques. The study of the sintering process involved different sintering programs, under different atmospheres conditions and additive utilization. Optimized conditions were established and the limiting factors discussed. The quality of the obtained ceramics was assessed by their final relative density, phase homogeneity, microstructure and optical properties (transmission, optical activity and electro-optical performance). Samples with relative density above 99,9% and 50% of the monocrystal´s optical transmission in the 633 nm wavelength and equal optical activity were obtained. Nevertheless...

Geração e Propriedades de Superposição de Estados Comprimidos deslocados.; Geração e Propriedades de Superposição de Estados Comprimidos deslocados.; Generation and Properties of Superposition of States Tablets displaced.; Generation and Properties of Superposition of States Tablets displaced.

WEBER, Paulo Estevão Rezende
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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A feasible scheme for generating squeezed states of superposiçãao displaced in superconducting cavities is presented. The characteristics and properties, especially the non-classical, are studied by means of the Wigner function and Q parameter of Mandel. The probability of successful generation of such superposition are also considered.; Um esquema factível de geração de superposiçãao de estados comprimidos deslocados em cavidades supercondutoras é apresentado. As características e propriedades, em especial as não clássicas, são estudadas por meio da funcão de Wigner e parâmetro Q de Mandel. A probabilidade de sucesso de geracão de tal superposição também são consideradas.

Efeito magnetoforético aplicado à separação de nanopartículas magnéticas biocompatíveis; Efeito magnetoforético aplicado à separação de nanopartículas magnéticas biocompatíveis; Magnetoforetic effect applied to biocompatible magnetic Nanoparticle segregation; Magnetoforetic effect applied to biocompatible magnetic Nanoparticle segregation

SANTOS, Marcus Carrião dos
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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In this work a magnetophoretic experiment (MPE) was developed to study the effect of a gradient of magnetic field in the diameter and size dispersivity of nanoparticles in a magnetic fluid (MF). In this experiment, the mass of a permanent magnet is measured by a balance which data varied due to the interaction with the magnetic fluid, which is placed a few centimeters above. Curves of variation of apparent mass of the magnet were obtained as function of time and related to the characteristics of fractions taken from the surface of the MF at different times. The MF consisted of magnetite nanoparticles surface-coated with phosphate. Samples were synthesized by the coprecipitation method and characterization was performed using x-ray diffraction, high resolution transmission electron microscopy (HR-TEM) and vibrating sample magnetometry (VSM). Fractions of the MF were taken during the MPE at five different times. Those fractions were characterized by VSM, from which magnetic diameters were estimated. The magnetic diameters showed a decrease of nanoparticle size in the surface of the MF sample submitted to MPE for longer times of exposure to the field gradient. These same fractions were characterized by HR-TEM and histograms of nanoparticles size distribution were made. Studies of mean and modal (obtained by lognormal fit) diameters had confirmed the behavior indicated by the magnetic diameters showing a decrease of size as function of time. Studies of standard deviation and full width at half maximum (obtained by lognormal fit) had shown a decrease in dispersivity. However...

Síntese e caracterização de compostos do sistema x/2 Al²O³-x/2 Y²O³ (100 - x) SiO² (x=10,20,30,40 e 50) dopados com Er³+ para aplicação em fotônica; Synthesis and characterization of the system x/2 Al²O³-x/2 Y²O³ (100 - x) SiO² (x=10,20,30,40 e 50) dopados com Er³+ para aplicação em fotônica.

OLIVEIRA, Alexandre Miranda de
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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This work is to study the crystallization of compounds in the form of post system alumina-yttria-silica prepared by sol-gel mixed methodology and Pechini. Powders (x / 2) Y ² ³ - (X / 2) Al ² O ³ - (1-x) SiO ² (x = 0.1 0.2, 0.3, 0.4 and 0.5 mol) were doped with erbium prepared and characterized. The physical properties of composite SiO ² ¹ YO-, 5 - AlO ¹, 5 were studied by x-ray diffraction, FTIR spectroscopy, thermogravimetry, differential thermal analysis and photoluminescence measurements. It was possible to maintain the amorphous compositions at high temperatures, no crystallization below 900 ° C and the formation of phase Y ² ² O7 Si at 1100 ° C. We obtained a reasonable life time of some compositions treated at 1000 ° C. We observed the emission of green upconversion to excite the samples with high power laser. All synthesized samples exhibit photoluminescence emission and have maximum emission at 1530 nm with a width of ~ 47nm. This broad issue is a desirable property for amplifiers used in systems division multiplexing wavelengths (WDM) and suggests that Er ³ + ions are hosted in the amorphous phase.; Neste trabalho estudo-se a cristalização de compostos na forma de pós do sistema alumina-ítria-sílica preparados pela metodologia mista sol-gel e Pechini. Pós de (x/2) Y²O³-(X/2) Al²O³-(1-x) SiO² (x=0...

Monte Carlo quântico aplicado ao estudo do comportamento quântico-clássico do Neônio; Monte carlo qapplied to study quantum-classic behavior of nein

CARVALHO, Thiago Milograno de
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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In this work we have applied Quantum Monte Carlo method at finite temperature known as Path Integral Monte Carlo (PIMC) to study the quantum-classical behavior of the Neon. We have calculated the one body density matrix as well as the atomic momentum distribution which have shown to be significantly different from the classical Maxwell- Boltzmman distribution in the range of densities and temperatures studied. The deviations from a classical gaussian are substantial but it decreases as one goes to temperatures above T = 35 K or densities below p = 20 nm−3. Furthermore, at low temperature the results show that there are more low momentum atoms than in a classical gaussian distribution.; Neste trabalho aplicamos o método de Monte Carlo Quântico à temperatura finita conhecido como Path Integral Monte Carlo (PIMC) a fim de estudar o comportamento quântico-clássico do Neônio. Calculamos a matriz densidade de um corpo, bem como a distribuição de momento atômica que mostrou ser significativamente diferente da distribuição clássica de Maxwell-Boltzmann nos intervalos de densidade e temperatura estudados. Os desvios de uma gaussiana clássica são substanciais porém esses desvios diminuem para temperaturas acima de T = 35 K ou densidades abaixo de p= 20 nm−3. Além disso...

Estudo da atividade antioxidante do 4-nerolidilcatecol por métodos analíticos e biofísicos; Study of the antioxidant activity of 4-nerolidylcatechol by analytical and biophysical methods

FERNANDES, Kelly de Souza
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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NOTE: As programs do not copy or copy errors with certain symbols, formulas, formatting ... etc, to view the summary and the entire file, click rm PDF - dissertation at the bottom of the screen.; OBS: Como programas não copiam ou copiam com erros certos símbolos, fórmulas, formatações... etc, para visualizar o resumo e todo o arquivo, click rm PDF - dissertação na parte de baixo da tel.

Estudo do efeito de nanopartículas magnéticas biocompatíveis no sistema cardiovascular de ratos e investigação do processo de captura e exocitose das nanoestruturas por cardiomiócitos; Study of the effect of magnetic nanoparticles biocampatible in the rat cardiovascular system and investigation of capture process and exocytosis for cardiomyocytes of nanostructures

RAMALHO, Laylla Silva
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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Magnetic fluids consist of surface-coated magnetic nanoparticles dispersed in a liquid carrier. These nanostructures have attracted a lot of attention of the biomedical community because of its possible applications as drug carriers, disease detection, and also on the treatment of several diseases, including cardiovascular ones. This work had the following objectives: (i) evaluate the effect ex-vivo of biocompatible magnetic nanoparticles in the rat heart function and, in-vivo, in the arterial blood pressure and heart rate of the rats, as well as, (ii) investigate the endocytosis and exocytosis of the nanoparticles through a magnetophoresis technique. The samples were characterized by X-ray diffraction (XRD), Dynamic light sacttering (DLS) and Vibrating sample magnetometer (VSM). The cardiac function was evaluated by the Langendorf technique under constant flow. On the other hand, in order to evaluate the effect of nanoparticles in the cardiovascular parameters, femoral artery and vein were cannulated and arterial pressure and heart rate were measure after 24 hs. The magnetic fluid infusion in the isolated heart showed a tiny increase of the intraventricular diastólic pressure and a decrease of the intraventricular systolic pressure. No changes were observed in perfusion pressure. The infusion of the magnetic nanoparticles in the rats had not promoted any significant variations of the artery pressure or the heart rate. These results suggest that magnetic nanoparticles can be used on clinical trials. In addition...

EQUAÇÕES DE LORENZ-CROSS NA FERROHIDRODINÂMICA; Equations LORENZ IN CROSS-FERROHIDRODINÂMICA

SASAKI, Nélio Martins da Silva Azevedo
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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In this work we investigated the problem of Rayleigh-Bénard for a magnetic binary fluid, i.e., a magnetic fluid, which consist of magnetic nanopartilces stably dispersed in a liquid carrier. The theoretical calculations were performed based on a Lorenz-like model, which transforms a system of partial differential equations into ordinary differential ones. The analysis of the magnetic binary fluid problem used the Navier-Stokes, thermal conduction and mass diffusion equations. The magnetic body force was obtained using the Cowley- Rosensweig tensor as well as the Maxwell equations. The mass flux had included the difusive contribution, associated to Fick s law, and also the thermal diffusion term, due to the Soret effect. Our model consist of a system of eight ordinary differential equations, which were shown to mantain the same mathematical form as the ones obtained earlier by Cross for a non-magnetic binary fluid. However, as expected, our coefficients depend on the magnetic field. According to our investigation on the site www.isiknowledge.com this is the first time in the literature that those equations are obtained, which we named the Lorenz-Cross equations on Ferrohydrodynamics. The validity of our system of equations were, also...

Espectro de Absorção da Orto-betaína em Água: um Estudo Teórico usando o Método Seqüencial Monte Carlo/Mecânica Quântica; Absorption spectrum of the ortho-betaine in Water: a Study Theoretical Method using Sequential Monte Carlo/Mechanics Quantum

OLIVEIRA, Leonardo Bruno Assis
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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Using sequential Monte Carlo simulation and quantum mechanics calculations(S-QM/MM) based on the TD-DFT methods we have been used to study the solvatochromic shift of the orto-betaine in water. Statistically uncorrelated configurations have been obtained from MC simulations with unpolarized and in-solution polarized solute. To account for the solute electronic polarization, we have used an iterative procedure based on the S-QM/MM methodology to determine the in-solution dipole moment of orto-betaine in presence of water molecules treated as point charges. MP2/cc-pVDZ calculations on the configurations bearing the orto-betaine molecule electrostatically embedded in the 320 water molecules show that the solute polarization increases the dipole moment of orto-betaine, compared to gas phase, by 49%, giving the in-solvent dipole values of 12.2 D. MC simulation results for the Helmholtz free energy as function of the torsion angle indicate that the mosts table conformer of the orto-betaine in water is that with an angle of 60o, after including solute polarization. The average number of solute-solvent hydrogen bonds was analyzed and it was found a large increase of 3,25 in polarized situation to only 1,82 in the unpolarized situation. Modeling the water molecules by point charges (electrostatic embedding)...

Estudo por ressonância ferromagnética das anisotropias uniaxial e unidirecional em bicamadas e tricamadas magnéticas; Ferromagnetic resonance study of the anisotropies uniaxial and unidirectional magnetic bilayer and tricamadas

Sousa, Marcos Antonio de
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
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The Ferromagnetic Resonance (FMR) technique at the X-band (~ 9.70 GHz) and Q-band (~ 34.0 GHz) was used to study the magnetic properties of NiO/Co, NiO/Py and Py/FeMn bilayers, and Co/NiO/Co trilayers with different thicknesses, deposited by dc magnetron sputtering technique in the presence of a 400 Oe magnetic field. The FMR experiments were all done at room temperature using a high sensitivity Bruker ESP-300 spectrometer, with static scanning field and usual modulation and phase sensitive detection techniques. The angular dependence of the inplane resonance field allows the measurement of the exchange bias field for some NiO/Py bilayers and the uniaxial anisotropy of the Co layer of NiO/Py bilayers and Co/NiO/Co trilayers. The value of the exchange bias field of the NiO/Py bilayers varies from 29 Oe to 123 Oe while the uniaxial anisotropy field of the Co layer, varies from 5 to 45 Oe. For Co/NiO/Co trilayers, the Co in-plane uniaxial anisotropy field varies from 34 to 216 Oe. The out-of-plane angular dependence of the resonance field allows the measurement of the effective magnetization and the g-factor, which depend not only on the specific parameters of the samples, such as thickness of the ferromagnetic layer, but also on the deposition conditions. The results obtained were compared with known values in the literature and show the high sensitivity of the ferromagnetic resonance technique in the study of the magnetic anisotropy and the exchange bias phenomena.; A técnica de ressonância ferromagnética (FMR) foi utilizada para estudar propriedades magnéticas de bicamadas NiO/Co...

Dinâmica molecular e particionamento do marcador de spin di-terc-butil nitróxido em membranas de estrato córneo. Efeito de Terpenos; Molecular dynamics and partitioning Bookmark spin di-tert-butyl nitroxide in membrane of stratum corneum. Effect of Terpenes

CAMARGOS, Heverton Silva de
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Física; Ciências Exatas e da Terra
Tipo: Dissertação Formato: application/pdf
POR
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Terpenes are a very promising class of skin penetration enhancers especially due to their low potential of irritation in the skin. In this work, we have used the electron paramagnetic resonance (EPR) spectroscopy of the small spin label di-tert-butyl nitroxide (DTBN), which partitions the aqueous and hydrocarbon phases, to study the interaction of the terpenes ®-terpineol, 1,8-cineole, L(-)-carvone and (+)-limonene with the uppermost skin layer, the stratum corneum, and the membrane models of 1,2-dipalmitoyl-sn-glycero- 3-phosphatidylcholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). The EPR spectra indicated that the terpenes increase both the partition coe±cient and the rotational di®usion rate of the spin labels in the stratum corneum membranes whereas for DMPC and DPPC bilayers were observed similar e®ects only at temperatures below the liquid-crystalline phase. The EPR parameter associated to probe polarity inside the membranes showed thermotropic induced changes, suggesting relocations of spin probe, which were dependent of the membrane phases. While DMPC and DPPC bilayers showed abrupt changes in the partitioning and rotational correlation time parameters at the phase transitions, the SC membranes were characterized by slights changes in whole interval of measured temperatures...

Soluções localizadas em modelos de campos relativísticos e em condensados de Bose-Einstein; Localized solutions in models of relativistic fields and Bose-Einstein condensates

CARDOSO, Wesley Bueno
Fonte: Universidade Federal de Goiás; BR; UFG; Doutorado em Fisica; Ciencias Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Doutorado em Fisica; Ciencias Exatas e da Terra
Tipo: Tese de Doutorado Formato: application/pdf
POR
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This work combines some of the results obtained on the study of solitons in relativistic fields and Bose-Einstein condensates. By using a first order formalism to solve the equations of motion of relativistic fields, introduced previously by our group, we construct several classes of lump solutions described by a single real scalar field. We show how these solutions can be controlled depending on a single parameter in the field potential. In condensed matter the solutions of the lump type correspond to bright solitons, very studied in the context of nonlinear crystals, fiber optics, Bose-Einstein condensates, etc. In all these cases, such solutions are obtained via a nonlinear Schr¨odinger equation, responsible for describing the propagation of pulses in optical fibers or crystals, or the atomic density in condensates. In this sense, our main goal is to study the soliton and breather modulations via nonlinear Schrodinger equation. We concentrate on the Bose-Einstein condensate in which the modulation of atomic density can be accomplished through the Feshbach resonance. We study cases where the nonlinearity is described by terms cubic, cubic and quintic, and purely quintic in the nonlinear Schr¨odinger equation. Also, situations where two interacting condensates in which the nonlinear Schr¨odinger equations are coupled...

Interações da albumina de soro bovino com surfactantes e efeitos de antioxidantes sobre a oxidação de lipoproteínas de baixa densidade induzida por íons de cobre; Interactions of bovine serum albumin with surfactants and effects of antioxidants on the oxidation of low density lipoproteins induced by cooper ions

ANJOS, Jorge Luiz Vieira dos
Fonte: Universidade Federal de Goiás; BR; UFG; Doutorado em Fisica; Ciencias Exatas e da Terra Publicador: Universidade Federal de Goiás; BR; UFG; Doutorado em Fisica; Ciencias Exatas e da Terra
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
135.83%
Human plasma contains primarily large proteins, ranging in composition and concentration as the individual's physiological state. Among these proteins, albumin and low density lipoprotein (LDL) have been widely studied. The albumin (the most abundant protein in blood plasma) is responsible for important functions in the human body due to its excellent ability to bind and transport small molecules. In turn, the LDL (responsible for transporting cholesterol to the cells) in its oxidized form is directly associated with atherosclerosis, the main cause of cardiovascular disease. In the first part of this work, the interaction of bovine serum albumin (BSA) with the ionic surfactants sodium dodecylsulfate (SDS), cetyltrimethylammonium chloride (CTAC) and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) was studied by electron paramagnetic resonance (EPR) spectroscopy of spin label covalently bound to the single free thiol group of the protein. In the second part was studied the oxidation of human LDL by copper ions and also the antioxidant potential of polyphenols resveratrol, (+)-catechin and quercetin, using the EPR of a spin label, derived from stearic acid (5-DSA), and the method malondialdehyde content (MDA). Part I: The dynamics of the BSA and the thermodynamic parameters for transferring the nitroxide side chain from the more motionally restricted to the less restricted component were monitored through EPR spectra simulation. Whereas SDS and CTAC showed similar increases in the dynamics of the protein backbone for all concentrations used...