Ⅰ. INTRODUCTION The original theory of the crystallization and nucleation was founded by M. Volmer and A. Weber according to the Gibbs thermodynamic phase equilibrium among the mother, the new and the surface phases,...Ⅰ. INTRODUCTION The original theory of the crystallization and nucleation was founded by M. Volmer and A. Weber according to the Gibbs thermodynamic phase equilibrium among the mother, the new and the surface phases, which is the basis for researchers to analyze the phenomena of crystallization and to study the process of nucleation. Because of the promotion of展开更多
A new crystal of aluminophosphate, AIPO4·H2O, is synthesized from two-batch aqueous solution under hydrothermal conditions. Three types of the crystal habits, i.e. the tetragonal double pyramid, the tetragonal pr...A new crystal of aluminophosphate, AIPO4·H2O, is synthesized from two-batch aqueous solution under hydrothermal conditions. Three types of the crystal habits, i.e. the tetragonal double pyramid, the tetragonal prism and the plate-type tetragonal prism, are found from batch-A solution. Two types of the crystal habits, i.e. the hexagonal pyramid and the strip-type tetragonal prism, are found from batch-B solution. The change of crystal morphology is originated from the fluctuation of the synthesis conditions, such as the supersaturation, the temperature and the impurity content. It causes change of the step energies, the defect density and the step roughness, and further, change of the growth rates. Since the crystal morphology is sensitive to the mass transport mechanism, the crystal habits could be changed under the microgravity.展开更多
Sodium chlorate is a no coloured,no smell and no poisonous transparent crystal with the formula of NaClO 3.Its structure belongs to the cubic( T 23)class and exhibits optical activity.The space group is P 2 13 and the...Sodium chlorate is a no coloured,no smell and no poisonous transparent crystal with the formula of NaClO 3.Its structure belongs to the cubic( T 23)class and exhibits optical activity.The space group is P 2 13 and there are four molecules per cubic unit cell with a =0.6570nm.We chose the crystal as a research system based on two reasons:(1)since the crystal structure belongs to the cubic class,the crystal faces,such as(100),(010),(001)are possessed of homogeneity,it is the suitable system for studying kinetics of crystal growth;(2)since the solubility of the NaClO 3 is higher in the H 2O and the crystal could be grown from low temperature solution,this is a suitable system for studying a influence of gravity on the boundary layer characteristics of the crystal growth under the microgravity condition.展开更多
文摘Ⅰ. INTRODUCTION The original theory of the crystallization and nucleation was founded by M. Volmer and A. Weber according to the Gibbs thermodynamic phase equilibrium among the mother, the new and the surface phases, which is the basis for researchers to analyze the phenomena of crystallization and to study the process of nucleation. Because of the promotion of
文摘A new crystal of aluminophosphate, AIPO4·H2O, is synthesized from two-batch aqueous solution under hydrothermal conditions. Three types of the crystal habits, i.e. the tetragonal double pyramid, the tetragonal prism and the plate-type tetragonal prism, are found from batch-A solution. Two types of the crystal habits, i.e. the hexagonal pyramid and the strip-type tetragonal prism, are found from batch-B solution. The change of crystal morphology is originated from the fluctuation of the synthesis conditions, such as the supersaturation, the temperature and the impurity content. It causes change of the step energies, the defect density and the step roughness, and further, change of the growth rates. Since the crystal morphology is sensitive to the mass transport mechanism, the crystal habits could be changed under the microgravity.
文摘Sodium chlorate is a no coloured,no smell and no poisonous transparent crystal with the formula of NaClO 3.Its structure belongs to the cubic( T 23)class and exhibits optical activity.The space group is P 2 13 and there are four molecules per cubic unit cell with a =0.6570nm.We chose the crystal as a research system based on two reasons:(1)since the crystal structure belongs to the cubic class,the crystal faces,such as(100),(010),(001)are possessed of homogeneity,it is the suitable system for studying kinetics of crystal growth;(2)since the solubility of the NaClO 3 is higher in the H 2O and the crystal could be grown from low temperature solution,this is a suitable system for studying a influence of gravity on the boundary layer characteristics of the crystal growth under the microgravity condition.
