We reviewed systems formed in liquid and solid helium-4 at high concentrations (10¹⁶ cm⁻³ and higher) of impurity particles. A new explanation for the reversible coagulation of fine hydrogen particles into big flakes observed upon the transition of liquid helium into the superfluid phase is proposed. The importance of nanoclusters presence in helium crystals doped with impurity particle for the metastability of icebergs is discussed.

中文翻译：

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冷凝氦 4 中的杂质系统

我们回顾了在高浓度（10 ¹⁶  cm ^-3及更高）杂质粒子的液态和固态氦 4 中形成的系统。提出了在液氦转变为超流相时观察到的细氢粒子可逆凝结成大薄片的新解释。讨论了掺杂杂质粒子的氦晶体中存在的纳米团簇对冰山亚稳态的重要性。