Phase Transitions
Mostrando 13-24 de 387 artigos, teses e dissertações.
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13. Pattern Identification on the Nonlinear Radial Motion of an Oscillating Spherical Bubble Using Neural Networks
Abstract The main goal of this article is to study the oscillatory motion of a spherical gas bubble immersed in a Newtonian liquid subjected to a harmonic pressure excitation. We use the classical Rayleigh-Plesset equation to study the radial motion of the bubble undergoing a forcing acoustic pressure field. The second order nonlinear ordinary differential e
Lat. Am. j. solids struct.. Publicado em: 2016-12
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14. Synthesis and Characterization of Nb2O5:La3+,Eu3+ Phosphors Obtained by the Non-Hydrolytic Sol-Gel Process
The phosphor-converted light-emitting diode technique is an important solid-state illumination strategy. Sulfide-based materials are the most often employed red phosphors, but they are chemically unstable and present lower efficiency in comparison to the blue and green phosphors. Therefore, it is important to find a new red phosphor source that can emit inte
J. Braz. Chem. Soc.. Publicado em: 2015-12
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15. Structure and Phase Transition of Fe-Mn Alloy Powders Prepared by Gas Atomization
In this paper we investigated the microstructure and phase transition of atomized Fe-(1.3, 7.9, 11.7 wt.%) Mn alloy powders. The results show that the main phases of Fe-1.3Mn, Fe-7.9Mn and Fe-11.7Mn powders are ferrite, α’-martensite+austenite, α’-martensite+ε-martensite+austenite, respectively. The δ-ferrite in the Fe-1.3Mn powder is the high-temper
Mat. Res.. Publicado em: 17/11/2015
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16. Pressure-induced Structures and Structural Evolution in Iron
Molecular-dynamic simulations have been used to study the structure evolution in iron melts rapidly cooled under different pressures. An extreme cooling rate (4×1012K/s) was adopted in the cooling process. The simulation results show that at the ambient pressure, martensitic transformation happened. However, at a pressure of 1.4GPa, the system passes from b
Mat. Res.. Publicado em: 17/11/2015
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17. Thermoanalytical studies of carbamazepine: hydration/dehydration, thermal decomposition, and solid phase transitions
A carbamazepina (CBZ) é um anticonvulsivante frequentemente utilizado no Brasil e em vários países. Ela apresenta quatro formas polimórficas e um diidrato. Todas as formas são ativas farmacologicamente, porém a Forma III é a preferível do ponto de vista farmacêutico, em função de suas propriedades físico-químicas. Entretanto, essa forma é altam
Braz. J. Pharm. Sci.. Publicado em: 2014-12
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18. Termalização e correlações quânticas nos contextos de sistemas quânticos abertos e cadeias de spins
In this thesis, we study the behavior of Quantum Discord in the contexts of open quantum systems and spin chains. Furthermore, we investigate the thermalization process of a spin chain due to interaction with the environment. First, we present a review on the concept of quantum correlation, beginning with the first ideas on non-locality, and leading to the m
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/01/2013
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19. Giant reversible magnetocaloric effect in flower-like β-Co(OH)2 hierarchical superstructures self-assembled by nanosheets
A facile hydrothermal strategy is proposed to synthesize flower-like β-Co(OH)2 hierarchical microspherical superstructures with a diameter of 0.5-1.5 μm, which are self-assembled by β-Co(OH)2 nanosheets with the average thickness ranging between 20 and 40 nm. The magnetocaloric effect associated with magnetic phase transitions in Co(OH)2 superstructures h
Mat. Res.. Publicado em: 11/10/2013
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20. Dielectric study at microwave frequencies of phase transitions in multiferroic ceramics
Multiferroic ceramic solid solutions between the ferroelectric relaxor Pb(Fe2/3W1/3)O3 (PFW) and "normal" ferroelectric PbTiO3 (PT) - PFW-PT have been synthesized by a modified B-site precursor method and characterized by microwave dielectric measurements. A dielectric dispersion occurring in the frequency range of 100MHz-3GHz and in a broad range of tempera
Mat. Res.. Publicado em: 16/07/2013
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21. Heat transfer to immiscible liquid mixtures in a spiral plate heat exchanger
This work presents new predictive correlations for heat transfer to immiscible liquid-liquid mixtures in a spiral plate heat exchanger. Liquid-liquid heat transfer studies were carried out in spiral plate heat exchangers for the water-octane, water-kerosene, and water-dodecane systems. For each composition of the mixture, the mass flow rate of the cold fluid
Braz. J. Chem. Eng.. Publicado em: 2013-06
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22. Solid-liquid equilibrium of triolein with fatty alcohols
Triacylglycerols and fatty alcohols are used in the formulation of cosmetic, pharmaceutical and food products. Although information about the phase transitions of these compounds and their mixtures is frequently required for design and optimization of processes and product formulation involving these substances, these data are still scarce in the literature.
Braz. J. Chem. Eng.. Publicado em: 2013-03
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23. Study of quantum effects in condensed matter thermodynamics : phase transitions at finite temperature / Estudo de efeitos quânticos na termodinâmica da matéria condensada : transições de fase a temperatura finita
Neste trabalho apresentaremos a extensão dos métodos adiabatic switching (AS), reversible scaling (RS) e integração dinâmica de Clausius-Clapeyron (d-CCI) para o formalismo de integral de tragetória. Desenvolvemos programas de Monte Carlo de integrais de trajetória (PIMC) para implementar esses métodos a fim de incluir efeitos quânticos nos cálculo
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/06/2012
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24. Molecular dynamics and formation of domains in block copolymers studied by high and low resolution NMR / Dinâmica molecular e formação de domínios em copolímeros em bloco estudados por RMN de alta e baixa resolução
The main objective of this dissertation is the use of NMR methods to characterize the phase separation and, to some extent, the dynamics of the molecular segments in block copolymers. In the first part, NMR Spin Diffusion methods were explored in order to evaluate their performance as well as the main experimental difficulties. For that, a reference tri-bloc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/04/2012