Prevenslik T V
14B, Brilliance Court, Discovery Bay, Hong Kong.
Ultrasonics. 2003 Jun;41(4):313-7. doi: 10.1016/s0041-624x(02)00458-4.
Over 150 years ago, Becquerel discovered the ultraviolet illumination of one of a pair of identical electrodes in liquid water produced an electric current, the phenomenon called the Becquerel effect. Recently, a similar effect was observed if the water surrounding one electrode is made to cavitate by focused acoustic radiation, which by similarity is referred to as the cavitation induced Becquerel effect. The current in the cavitation induced Becquerel effect was found to be semi-logarithmic with the standard electrode potential that is consistent with the oxidation of the electrode surface by the photo-decomposition theory of photoelectrochemistry. But oxidation of the electrode surface usually requires high temperatures, say as in cavitation. Absent high bubble temperatures, cavitation may produce vacuum ultraviolet (VUV) light that excites water molecules in the electrode film to higher H(2)O(*) energy states, the excited states oxidizing the electrode surface by chemical reaction. Solutions of the Rayleigh-Plesset equation during bubble collapse that include the condensation of water vapor show any increase in temperature or pressure of the water vapor by compression heating is compensated by the condensation of vapor to the bubble wall, the bubbles collapsing almost isothermally. Hence, the cavitation induced Becquerel effect is likely caused by cavitation induced VUV light at ambient temperature.
150多年前，贝克勒尔发现，在液态水中，一对相同电极中的一个受到紫外线照射会产生电流，这种现象被称为贝克勒尔效应。最近，如果通过聚焦声辐射使围绕一个电极的水产生空化现象，也会观察到类似的效应，根据相似性，这被称为空化诱导贝克勒尔效应。研究发现，空化诱导贝克勒尔效应中的电流与标准电极电位呈半对数关系，这与光电化学的光分解理论中电极表面的氧化情况一致。但是电极表面的氧化通常需要高温，比如在空化现象中。在没有高气泡温度的情况下，空化可能会产生真空紫外线（VUV），使电极薄膜中的水分子激发到更高的H(2)O(*) 能态，这些激发态通过化学反应氧化电极表面。在气泡崩溃过程中，包含水蒸气凝结的瑞利-普莱塞特方程的解表明，水蒸气因压缩加热而导致的温度或压力的任何升高都会被水蒸气凝结到气泡壁上所补偿，气泡几乎在等温条件下崩溃。因此，空化诱导贝克勒尔效应很可能是由常温下空化诱导产生的真空紫外线引起的。
