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Information × Registration Number 0216U002961, 0115U003846 , R & D reports Title Bulk and surface mesoscopic objects in condensed phases of helium popup.stage_title Head Sharapova Iryna Volodymyrivna, Registration Date 03-01-2017 Organization B.Verkin Institute for Low Temperature Physics and Engineering NAS of Ukraine popup.description2 First experimental study is carried out of superfluid 4Не in the laminar and turbulent flows by using the method of quartz tuning fork in the temperature range from 0,1 to 3,5 К. It is found that there is the frequency dependence of the drag coefficient in the hydrodynamic limit at temperatures Т > 700 mК. At Т < 700 mК the dependence of drag coefficient on the frequency is not available, and the magnitude of the dissipative losses is determined only by the temperature dependence of the density of the normal component. The study of the transition from the laminar to turbulent flow showed that there is the quasi-laminar flow in liquid helium. First experimental study is carried out of the dissipative processes features in 15% solution 3Не - 4Не in the temperature range 0,5 - 2,3 К. The resonance curves of tuning forks were measured in the laminar flow region of the liquid. It is found that a significant contribution to the damping of oscillations of the tuning fork in the solution is from the second sound radiation which contribution exceeds that of viscous dissipation. It is shown that in superfluid solutions the increase of the impurity concentration of 3He leads to the increasing of the stability the liquid with respect to the formation of vortices and the transition to the turbulent state. Also there were first established conditions of cavitation in superfluid solution of helium isotopes. The transport properties of the electron crystal over liquid helium under incomplete compensation of the holding potential are researched. By modeling it is shown that the electron crystal response is not a result of the layer resistance change, but is due to features of the capacitance measurements of the two-dimensional electron system transport characteristics. Product Description popup.authors Бахвалова Валерія Анатоліївна Гриценко Іван Анатолійович Шарапова Ірина Володимирівна popup.nrat_date 2020-04-02 Close