相关实验视频
Updated: May 18, 2026

12:29
Optimization of Crystal Growth for Neutron Macromolecular Crystallography
Published on: March 13, 2021
在过热的合体晶体融化过程中成像同质核化
Ziren Wang1, Feng Wang, Yi Peng
1Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China.
概括
在单颗粒分辨率下观察到合体晶体的均融化. 核聚变的前体涉及粒子交换循环,因核凝聚而偏离经典理论.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学是一种材料科学.
- 物理化学 物理化学
背景情况:
- 核化是相变的关键,但它的动力学难以预测和测量.
- 了解同质核化对于控制材料性质至关重要.
研究的目的:
- 为了研究单颗粒分辨率在合晶体中均融化的动力学.
- 识别核化前体,并将实验结果与经典核化理论进行比较.
主要方法:
- 过热和融化热敏的合体晶体.
- 高分辨率视频显微镜用于单粒子跟踪.
- 对粒子移位幅度和核演变的分析.
主要成果:
- 观察到的核化前体作为局部粒子交换环,而不是缺陷.
- 测量了关键核大小,化时间和形状/大小演变.
- 由于在强烈的超热下核凝聚而与经典核化理论的偏离.
结论:
- 经典核化理论需要对强烈的超热条件进行修改,特别是考虑到核凝聚.
- 测量的超热极限与波恩和林德曼不稳定性一致.
- 提供了对基本化和核化过程的新见解.
相关概念视频
Recrystallization: Solid–Solution Equilibria
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
Crystal Growth: Principles of Crystallization
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Colloidal precipitates
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
Precipitation Processes
The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...
The Colloidal State
The formation of a colloidal system is exemplified by an aqueous solution containing Cl− ions is introduced to another containing Ag+ ions, resulting in the precipitation of solid AgCl as extremely tiny crystals. Instead of settling out as a filterable precipitate, these crystals remain suspended in the liquid, showcasing a colloidal system.A colloidal system involves colloidal particles within the approximate range of 1 to 1000 nm in at least one dimension, dispersed in a medium called the...

