On the role of surface charges for homogeneous freezing of supercooled water microdroplets.
On the role of surface charges for homogeneous freezing of supercooled water microdroplets.
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表面电荷对过冷水微滴均匀冻结的作用
DOI：
10.1039/c2cp23653b
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
T. Leisner
中科院分区：
文献类型：
--
作者：
D. Rzesanke;J. Nadolny;D. Duft;R. M¨uller;A. Kiselev;T. Leisner
电荷引起的水的均匀冻结速率的变化已经被提出来构成全球大气电路和云微物理学之间的可能联系，从而气候。我们在这里报告的高精度测量的均匀成核率的带电，电动悬浮的单个水滴作为其表面电荷的函数。没有证据表明过冷微滴的均匀体积比冰成核速率受表面电荷的影响，表面电荷在+/-200元电荷/μm2之间。也有人认为，在高度带电的液体中，在远高于均匀冻结极限的温度下，再结晶会引起冻结。我们在这里报告的库仑不稳定性的高度带电的液滴，伴随着从液体过冷液滴的细丝的形成和喷射的观察。下降到240 K的温度，这是接近不带电的水的均匀冻结极限，没有检测到诱导冻结。在更低的温度下，液滴在达到不稳定性之前冻结。这些发现排除了对流对过冷水中冰形成的重要影响。结合这些研究结果，我们得出结论，表面电荷（即使在其最大可能的密度）有过冷云滴的均匀冰成核率没有显着的影响。
Charge induced changes in homogeneous freezing rates of water have been proposed to constitute a possible link between the global atmospheric electric circuit and cloud microphysics and thus climate. We report here on high precision measurements of the homogeneous nucleation rate of charged, electro-dynamically levitated single water droplets as a function of their surface charge. No evidence has been found that the homogeneous volume specific ice nucleation rate of supercooled microdroplets is influenced by surface charges in the range between +/−200 elementary charges per μm2. It has also been suggested that filamentation in highly electrified liquids can induce freezing at temperatures well above the homogeneous freezing limit. We report here the observation of Coulomb instabilities of highly charged droplets that are accompanied with the formation and ejection of fine filaments from the liquid supercooled droplets. Down to temperatures of 240 K, which is close to the homogeneous freezing limit of uncharged water, no filamentation induced freezing has been detected. At even lower temperatures, the droplets froze before the instability was reached. These findings rule out that filamentation exerts an important influence on ice formation in supercooled water. Combining these findings, we conclude that the surface charges (even at their maximum possible density) have no significant effect on the homogeneous ice nucleation rate of supercooled cloud droplets.
DOI：
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发表时间：
1969
期刊：
影响因子：
--
作者：
M. A. Abbas;J. Latham
通讯作者：
J. Latham
Herrn 教授 Walter Noddack 博士 zum 60. Geburtstag
DOI：
10.1515/znb-1953-0813
发表时间：
1953
期刊：
Zeitschrift für Naturforschung B
影响因子：
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作者：
W. Feit
通讯作者：
W. Feit
影响因子：
56.9
作者：
R. Salt
通讯作者：
R. Salt