The microscopic visualisation of the sonocrystallisation of ice using a novel ultrasonic cold stage
The microscopic visualisation of the sonocrystallisation of ice using a novel ultrasonic cold stage
复制标题
DOI：
10.1016/j.ultsonch.2004.01.018
复制
发表时间：
2004-05-01
影响因子：
8.4
通讯作者：
Chivers, R
中科院分区：
文献类型：
--
作者：
Chow, R;Blindt, R;Chivers, R
这项工作报告了在微观水平上超声空化对冰的超声结晶影响的动态视频图像。这是通过构建一种独特的光学显微镜超声系统实现的。该系统由(1)超声波冷台，(2)温度控制系统和(3)显微镜和成像装置组成。这使得样品的温度可以被系统地控制，同时在超声波频率范围内受到交替压力的同时激励。激励的幅度和频率都可以改变。在纯水和蔗糖溶液中对冰晶进行了实验。观察到三种不同的现象。首先，在冰晶之间的晶界处有形成空化气泡的趋势。其次，由于空化气泡的作用，冰会逐渐融化，这些空化气泡似乎会蚕食冰相。其三，树突冰结构在超声作用下可能发生破碎，从而增加随后生长的核的数量（二次成核）。这些观测结果为大大提高对冰的声结晶的理解和利用奠定了基础。(C) 2004 Elsevier B.V.版权所有
This work reports dynamic video images of the influence of ultrasonic cavitation on the sonocrystallisation of ice at a microscopic level. This has been achieved through the construction of a unique ultrasonic system for an optical microscope. The system consists of (1) an ultrasonic cold stage, (2) a temperature control system, and (3) a microscope and imaging setup. This allows the temperature of a sample to be systematically controlled while it is subjected to simultaneous excitation with alternating pressures in the ultrasonic frequency range. Both the amplitude of excitation and the frequency can be varied.Experiments on ice crystals in pure water and sucrose solutions were conducted. Three distinct phenomena were observed. Firstly, there is a tendency for cavitation bubbles to form at the grain boundaries between ice crystals. Secondly, there is a progressive melting of ice by cavitation bubbles which appear to eat their way into the ice phase. Thirdly, the dendritic ice structures may fragment under the influence of ultrasound, thus increasing the number of nuclei which may subsequently grow (secondary nucleation). These observations form the basis of a significantly enhanced understanding and exploitation of the sonocrystallisation of ice. (C) 2004 Elsevier B.V. All rights reserved.