The growth kinetics of LSCO and YBCO single crystals from high temperature solution of LSCO-CuO solute-solvent and YBCO-CuO solute-solvent systems has been investigated. Based on regular solution model and classical n...The growth kinetics of LSCO and YBCO single crystals from high temperature solution of LSCO-CuO solute-solvent and YBCO-CuO solute-solvent systems has been investigated. Based on regular solution model and classical nucleation theory, the thermodynamical data investigated for the systems are used to determine the nucleation parameters: interfacial free energy, metastable zone-width, volume free energy, critical energy barrier for nucleation and radius of critical nucleus for LSCO and YBCO which leads to the understanding of the nucleation phenomena of LSCO and YBCO.展开更多
Efficient modelling approaches capable of predicting the behavior and effects of nanoparticles in cement-based materials are required for conducting relevant experiments.From the microstructural characterization of a ...Efficient modelling approaches capable of predicting the behavior and effects of nanoparticles in cement-based materials are required for conducting relevant experiments.From the microstructural characterization of a cement-nanoparticle system,this paper investigates the potential of cell-based weighted random-walk method to establish statistically significant relationships between chemical bonding and diffusion processes of nanoparticles within cement matrix.LaSr_(0.5)C_(0.5)O_(3)(LSCO)nanoparticles were employed to develop a discrete event system that accounts for the behavior of individual cells where nanoparticles and cement components were expected to interact.The stochastic model is based on annihilation(loss)and creation(gain)of a bond in the cell.The model considers both chemical reactions and transport mechanism of nanoparticles from cementitious cells,along with cement hydration process.This approach may be useful for simulating nanoparticle transport in complex 2D cement-based materials systems.展开更多
Epitaxial Ba0.6Sr0.4TiO3 （BST） thin films were deposited on LaAlO3 （LAO） substrates with the conductive metallic oxide La0.5 Sr0.5CoO3 （LSCO） film as a bottom electrode by pulsed laser deposition （PLD）. X-ray ...Epitaxial Ba0.6Sr0.4TiO3 （BST） thin films were deposited on LaAlO3 （LAO） substrates with the conductive metallic oxide La0.5 Sr0.5CoO3 （LSCO） film as a bottom electrode by pulsed laser deposition （PLD）. X-ray diffraction 0-20 andФ scan showed that the epitaxial relationship of BST/LSCO /LAO was [001] BST// [001] LSCO//[001] LAO. The atomic force microscope （AFM） revealed a smooth and crack-free surface of BST films on LSCO-coated LAO substrate with the average grain size of 120 nm and the RMS of 1.564 nm for BST films. Pt/BST/LSCO capacitor was fabricated to perform Capacitance-Voltage measurement indicating good insulating characteristics. For epitaxial BST film, the dielectric constant and dielectric loss were determined as 471 and 0.03, respectively. The tunabilty was 79.59% and the leakage current was 2.63×10^-7 A/cm^2 under an applied filed of 200 kV/cm. Furthermore, it was found that epitaxial BST （60/40） fdms demonstrate well-behaved ferroelectric properties with the remnate polarization of 6.085μC/cm^2 and the coercive field of 72 kV/cm. The different electric properties from bulk BST （60/40） materials with intrinsic paraelectric characteristic are attributed to the interface effects.展开更多
文摘The growth kinetics of LSCO and YBCO single crystals from high temperature solution of LSCO-CuO solute-solvent and YBCO-CuO solute-solvent systems has been investigated. Based on regular solution model and classical nucleation theory, the thermodynamical data investigated for the systems are used to determine the nucleation parameters: interfacial free energy, metastable zone-width, volume free energy, critical energy barrier for nucleation and radius of critical nucleus for LSCO and YBCO which leads to the understanding of the nucleation phenomena of LSCO and YBCO.
基金Project(93021714)supported by the Iran National Science Foundation。
文摘Efficient modelling approaches capable of predicting the behavior and effects of nanoparticles in cement-based materials are required for conducting relevant experiments.From the microstructural characterization of a cement-nanoparticle system,this paper investigates the potential of cell-based weighted random-walk method to establish statistically significant relationships between chemical bonding and diffusion processes of nanoparticles within cement matrix.LaSr_(0.5)C_(0.5)O_(3)(LSCO)nanoparticles were employed to develop a discrete event system that accounts for the behavior of individual cells where nanoparticles and cement components were expected to interact.The stochastic model is based on annihilation(loss)and creation(gain)of a bond in the cell.The model considers both chemical reactions and transport mechanism of nanoparticles from cementitious cells,along with cement hydration process.This approach may be useful for simulating nanoparticle transport in complex 2D cement-based materials systems.
基金This work was supported by the youth science and technology fund of University of Electronic Science and Technology of China No.L08010301JX0617.
文摘Epitaxial Ba0.6Sr0.4TiO3 （BST） thin films were deposited on LaAlO3 （LAO） substrates with the conductive metallic oxide La0.5 Sr0.5CoO3 （LSCO） film as a bottom electrode by pulsed laser deposition （PLD）. X-ray diffraction 0-20 andФ scan showed that the epitaxial relationship of BST/LSCO /LAO was [001] BST// [001] LSCO//[001] LAO. The atomic force microscope （AFM） revealed a smooth and crack-free surface of BST films on LSCO-coated LAO substrate with the average grain size of 120 nm and the RMS of 1.564 nm for BST films. Pt/BST/LSCO capacitor was fabricated to perform Capacitance-Voltage measurement indicating good insulating characteristics. For epitaxial BST film, the dielectric constant and dielectric loss were determined as 471 and 0.03, respectively. The tunabilty was 79.59% and the leakage current was 2.63×10^-7 A/cm^2 under an applied filed of 200 kV/cm. Furthermore, it was found that epitaxial BST （60/40） fdms demonstrate well-behaved ferroelectric properties with the remnate polarization of 6.085μC/cm^2 and the coercive field of 72 kV/cm. The different electric properties from bulk BST （60/40） materials with intrinsic paraelectric characteristic are attributed to the interface effects.
