There are two main mysteries in bulk nanobubbles which are cavitation nuclei. One is the mechanism of stability of a bulk nanobubble. The other is the problem whether OH radicals are produced from bulk nanobubbles without a dynamic stimulus. For the former problem, several proposed models are briefly reviewed. The dynamic equilibrium model is discussed in details that a bulk nanobubble is stabilized by a partial coverage of the bubble surface by a hydrophobic material. The TEM images of bulk nanobubbles seem to support the dynamic equilibrium model. For the latter problem, numerical simulations of dissolution of an air nanobubble are reviewed, which suggest that no OH radical is produced from a dissolving nanobubble. A possible role of H₂O₂ generated during bulk nanobubble production using hydrodynamic cavitation is briefly discussed in relation to the experimental results of “OH radical” detection.

大量纳米气泡中的两个主要奥秘是空化核。一种是块状纳米气泡的稳定性机制。另一个问题是是否在没有动态刺激的情况下从大量的纳米气泡中产生了OH自由基。对于前一个问题，简要回顾了几种建议的模型。详细讨论了动态平衡模型，即通过疏水材料对气泡表面的部分覆盖来稳定整体纳米气泡。块状纳米气泡的TEM图像似乎支持动态平衡模型。对于后一个问题，回顾了空气纳米气泡溶解的数值模拟，这表明溶解的纳米气泡不会产生OH自由基。H ₂ O _2的可能作用 结合“ OH自由基”检测的实验结果，简要讨论了使用水力空化在大体积纳米气泡生产过程中产生的碳纳米管。