Solid Helium
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Simulações Monte Carlo de integrais de trajetória : propriedades elásticas do 4He sólido / Path integrals Monte Carlo simulations : elastic properties of 4He
The path-integral Monte Carlo (PIMC) method is a sophisticated approach for the simulation of many-body quantum systems. In particular, it has been extensively used for the study of manybody bosonic systems such as 4He. The main objective of the present dissertation is to apply the PIMC method to determine the elastic constants of solid 4He in its hcp phase.
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/11/2010
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2. Folatos, capacidade antioxidante e trans-2-nonenal em cerveja brasileira / Folate, antioxidant capacity and E-2-nonenal in Brazilian beer
In the present study methods were adapted and applied to quantify levels of folate, antioxidant capacity assessment and E-2-nonenal quantification in Brazilian beers. 5 brands of Pilsen, non-alcoholic and Malzbier beers were used, in can and amber bottle. For determination of folates (folic acid - FA, 10-methyl-folic acid - 10Methyl, 5-methyltetrahydrofolate
Publicado em: 2010
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3. Sistemas eletrônicos em duas dimensões : desordem e resposta dinâmica
In disordered systems the pinning strength on the carriers due to impurities or defects is one of the most important mechanisms that produce insulator behavior. A transition to a metal phase should occur if a driving field is applied to the system. In the last three decades, such transition in two-dimensional systems has attracted much attention in light of
Publicado em: 2009
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4. Teorias variacionais dos sistemas formados por atomos de 4He / Variational theories for systems of 4He atoms
This work proposes two variational wave functions based on the concept of shadow particles that describes the solid phase of systems formed by atoms of 4He. One of them, called Periodic Free Shadow Wave Function (PFS) provides good results for this phase like the energies of the system and the Radial Distribution Function that proved to be in good agreement
Publicado em: 2008
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5. Determining plasma morphine levels using GC-MS after solid phase extraction to monitor drug levels in the postoperative period
OBJECTIVE: To implement a selective and sensitive analytical method to quantify morphine in small volumes of plasma by gas-liquid chromatography-mass spectrometry (GC-MS), aimed at post-operatively monitoring the drug. METHOD: A gas-liquid chromatographic method with mass detection has been developed to determine morphine concentration in plasma after solid
Clinics. Publicado em: 2008
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6. Moisture effective diffusivity in porous solid mixtures / Difusividade efetiva de agua em misturas de solidos porosos
Porous solids have been applied in several industrial sectors, mainly as mixture of different solids. The physical characterization as well as the effective diffusivity of these materiaIs are important to the optimization of industrial processes that apply mass transport in porous solids. Investigations about effective diffusivity in solid mixture indicated
Publicado em: 2007
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7. Propriedades estruturais de misturas ternarias de solidos
In industrial processes, there are many examples of the use of mixture of different particles, that is, multicomponent solids. The knowledge of the properties of solids mixtures from the properties of the pure materials is of wide application in such processes. Possibly bringing advantages and improvements to the industrial processes. Therefore, the objectiv
Publicado em: 2002
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8. Uso de metodo sol-gel e de coprecipitação na preparação de oxidos metalicos
This thesis describes the preparation of two crystalline solids obtained by thermal decomposition of poorly crystallized solids obtained by precipitation techniques. Magnetite a ferrimagnetic crystalline solid, was obtained by heating non-crystalline iron (III) hidroxoacetate (HAFe), under nitrogen. Mixed oxides of La-Ba-Cu and Y-Ba-Cu, which are superconduc
Publicado em: 1992
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9. Estudo das correlações em líquidos clássicos / Study of the correlations in classical liquids
We have studied in this work three different classic fluid systems. The first one, formed by polystyrene spheres adsorbed on water, can be described by a dipolar (1/r3) interaction. Theradial correlation function and static structure factor as well the correlation energy and Helmholtz free energy were obtained in the framework of the Hypernetted Chain (HNC)
Publicado em: 1983
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10. Significant structure theory applied to liquid helium-3
The significant structure theory of liquids is successfully applied to the quantum liquid 3He. The partition function uses the Debye partition function for the solid-like molecules and the Fermi-Dirac partition function for the gas-like degrees of freedom. To evaluate the gas-like partition function, numerical calculations are performed and some integral fun
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11. Chemical composition of gaseous nebula NGC 6302
The irregular emission nebula NGC 6302 exhibits a rich spectrum of lines ranging in excitation from [NI] to [FeVII]. An assessment of available spectroscopic data, covering a large intensity range, indicates excess of helium and nitrogen as compared with average planetary nebulae, but deficiencies in iron and calcium. These metals are presumably tied up in s
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12. Atomic resolution images of solid-liquid interfaces
A scanning tunneling microscope (STM) can provide atomic-resolution images of solids covered with a variety of liquids, including cryogenic fluids, both polar and nonpolar solvents, conductive aqueous solutions, oils, and even greases. This short overview includes images of solids covered with liquid nitrogen, liquid helium, paraffin oil, silicone oil, micro