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Solid-liquid Interface (solid-liquid + interface)

Distribution by Scientific Domains

Polymers and Materials Science	36%
Physics and Astronomy	36%

Selected Abstracts

An Algorithm for Simulating Equilibrium Adsorption Characteristics of Branched Copolymer Chains at Solid-Liquid Interface

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 4 2007
Juedu Austine
Abstract An algorithm is developed for simulating adsorption of tree type block-branched copolymer chains, of arbitrary architecture, from dilute solutions to solid surfaces. A continuum form of the self-consistent field (SCF) theory is used. The chain architecture is first represented by a convergent tree-graph, which is then converted into a special type of the connectivity matrix. This matrix is used for computing the configurational statistics of the chains in the adsorbed layer. The crucial step in the algorithm is to compute the junction (branch point) probability weights. A stepwise procedure for computing these probability weights is described. The capability of the algorithm has been demonstrated using illustrative examples. [source]

Adsorption Behavior of Asymmetrical Triblock Copolymers at the Solid-Liquid Interface by Monte Carlo Simulation

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 8 2004
Changjun Peng
Abstract Summary: Monte Carlo simulation on a simple lattice model has been used to study the adsorption of asymmetrical triblock copolymers from a non-selective solvent at the solid-liquid interface. The size distributions of train, loop and tail configurations for those copolymers are obtained as well as other details of the adsorption layer microstructure. Also the influence of adsorption energy and the role of molecular symmetry are investigated. A segment-density profile, the adsorption amount, the surface coverage, and the adsorption layer thickness have been determined. Finally, it is shown that the adsorption behavior of an asymmetrical copolymer can be predicted from the symmetrical copolymer. Size distributions of the tail configuration for A8,kB20Ak. [source]

Dynamic Processes at Solid-liquid Interfaces

IMAGING & MICROSCOPY (ELECTRONIC), Issue 1 2006
Video-STM Images Nanoscale Dynamics
Scanning tunnelling microscopy (STM) not only provides unsurpassed resolution, enabling real-space imaging of individual surface atoms, but also is capable to operate in a wide range of environments, ranging from ultrahigh vacuum to gases and liquids. The latter allows studies of processes at solidliquid interfaces with a time resolution that can be as low as some 10 msec. in modern instruments. This is sufficiently fast to study elementary transport processes at these interfaces, such as surface diffusion or crystal growth, directly on the atomic scale. [source]

Optimization of control parameters of cadmium zinc telluride Bridgman single crystal growth

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2007
Liu Juncheng
Abstract The temperature gradient within a furnace chamber and the crucible pull rate are the key control parameters for cadmium zinc telluride Bridgman single crystal growth. Their effects on the heat and mass transfer in front of the solid-liquid interface and the solute segregation in the grown crystal were investigated with numerical modeling. With an increase of the temperature gradient, the convection intensity in the melt in front of the solid-liquid interface increases almost proportionally to the temperature gradient. The interface concavity decreases rapidly at faster crucible pull rates, while it increases at slow pull rates. Moreover, the solute concentration gradient in the melt in front of the solid-liquid interface decreases significantly, as does the radial solute segregation in the grown crystal. In general, a decrease of the pull rate leads to a strong decrease of the concavity of the solid-liquid interface and of the radial solute segregation in the grown crystal, while the axial solute segregation in the grown crystal increases slightly. A combination of a low crucible pull rate with a medium temperature gradient within the furnace chamber will make the radial solute segregation of the grown crystal vanish. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

New Developments in Vertical Gradient Freeze Growth,

ADVANCED ENGINEERING MATERIALS, Issue 7 2004
O. Pätzold
The Vertical Gradient Freeze (VGF) technique is an important method for growing high quality compound semiconductors such as GaAs. Results obtained with a novel VGF set-up developed for the growth under influence of a rotating magnetic field (RMF) and under vapour pressure control are presented in this paper. The RMF is shown to be a powerful tool to affect the heat and mass transport within the melt in a definite way. In GaAs:Si growth, RMF induced flow results in a decreased curvature of a nominally concave-shaped interface, i.e., it contributes to an axial heat transfer at the solid-liquid interface. The axial dopant segregation of Ga in Ge is found to be improved under continuous RMF action due to better mixing of the melt. The set-up also allowed to determine the influence of carbon and the arsenic vapour pressure on the dopant incorporation and crystal quality. [source]

An investigation of the mechanisms of ultrasonically enhanced desorption

AICHE JOURNAL, Issue 2 2007
Oualid Hamdaoui
Abstract In this work, the mechanisms underlying ultrasonic desorption of 4-chlorophenol from granular activated carbon have been explored. Desorption experiments are investigated in the absence and presence of 516 kHz ultrasound of different intensities. Using three regenerating solutions and two temperatures, it has been shown that ultrasonic irradiation considerably improves both the amount and the rate of desorption. Desorption increases with increasing temperature and ultrasound intensity. The addition of sodium hydroxide or a mixture of sodium hydroxide and ethanol to the regenerating medium leads to an enhancement of the desorption, especially in the presence of ultrasound. The mechanisms of ultrasonically enhanced desorption is due both to the thermal and non-thermal (hydrodynamical) effects of ultrasound. Hydrodynamical phenomena are principally produced by the acoustic vortex microstreaming within porous solids as well as at the solid-liquid interface and by the high-speed micro-jets and high-pressure shock waves produced by acoustic cavitation. The thermal effects are evaluated as localized hot spots formed when bubbles cavitated as well as by global heating of the medium and piezoelectric transducer heating-up. Additionally, the non-thermal effect of ultrasound is greater than the thermal effect, and it is more noticeable when the ultrasonic irradiation is carried out in a high temperature regenerating medium. © 2007 American Institute of Chemical Engineers AIChE J 2007 [source]

Adsorption Behavior of Asymmetrical Triblock Copolymers at the Solid-Liquid Interface by Monte Carlo Simulation

InxGa1,xAs single crystal growth by dispersing local misfit stress

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2006
Hiroaki Miyata
Abstract We succeeded in growing a single crystal by dispersing the misfit stress around an initial solid-liquid interface in In0.3Ga0.7As ternary bulk crystal growth. We gradually increased concentration of indium arsenide so that the local misfit stress could be smaller than critical resolved shear stress. The traveling lqiuidus-zone (TLZ) method was applied for growing crystals. To grow a single In0.3Ga0.7As crystal, an In0.1Ga0.9As single crystal region was grown first on a GaAs seed. Then the concentration of indium arsenide was gradually increased up to In0.3Ga0.7As by lowering temperature at the interface. As a result, In0.3Ga0.7As single crystals of 2 mm in thickness, 10 mm in width and more than 25 mm in length were successfully obtained. Mean value of full width half maximum (FWHM) of X-ray rocking curves in the In0.3Ga0.7As grown crystal was 0.116°. It is not small enough but it will be improved by increasing compositional homogeneity. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Effect of variable crucible dropping rate on solid-liquid interface in CdZnTe crystal growth

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2010
Chenying Zhou
Abstract The Cd0.9Zn0.1Te crystal growth with low pressure and vertical Bridgman method (LPVB) was numerically simulated and analysed by the simulation software of Comsol Multiphysics. In the process of crystal growth, the influence of variable crucible dropping rate on solid-liquid interface was studied in this paper. The variability of crucible dropping rate was achieved by a specifical furnace temperature distribution function, while the selection and analysis of crucible dropping rate was obtained by the combination of orthogonal experimental design method and regression analysis method. In this paper, the value of relative crystal growth rate was defined, and the influence of variable crucible dropping rate on solid-liquid interface was discussed by comparing these values. The simulation results showed that if the crucible dropping rate was 3.5 mm/h (,1) in the first stage and 0.6 mm/h (,2) in the second stage, and the distance (d) between the bottom of crucible and the position of melting point in tempreture field was 0.02 m at the time of dropping rate change, the solid-liquid interface was appreciably convex after 211 hours' growth, and the relative crystal growth rate was 0.45%, which made the solid-liquid interface smooth and kept the crystal grow up spontaneously. [source]

Factors influencing antibody stability at solid,liquid interfaces in a high shear environment

BIOTECHNOLOGY PROGRESS, Issue 5 2009
James G. Biddlecombe
Abstract A rotating disk shear device was used to study the effect of interfacial shear on the structural integrity of human monoclonal antibodies of IgG4 isotype. Factors associated with the solution conditions (pH, ionic strength, surfactant concentration, temperature) and the interface (surface roughness) were studied for their effect on the rate of IgG4 monomer loss under high shear conditions. The structural integrity of the IgG4 was probed after exposure to interfacial shear effects by SDS-PAGE, IEF, dynamic light scattering, and peptide mapping by LC-MS. This analysis revealed that the main denaturation pathway of IgG4 exposed to these effects was the formation of large insoluble aggregates. Soluble aggregation, breakdown in primary structure, and chemical modifications were not detected. The dominant factors found to affect the rate of IgG4 monomer loss under interfacial shear conditions were found to be pH and the nanometer-scale surface roughness associated with the solid-liquid interface. Interestingly, temperature was not found to be a significant factor in the range tested (15,45°C). The addition of surfactant was found to have a significant stabilizing effect at concentrations up to 0.02% (w/v). Implications of these findings for the bioprocessing of this class of therapeutic protein are briefly discussed. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]