Experimental Investigation on the Feasibility and Optimal Frequency of Ultrasonic Assisted Ice Drilling Method

Exploitation of polar resources and scientific research require efficient ice drilling technology. Thermal drilling is a common method for polar ice drilling, and is similar to the principle of ultrasonic assisted drilling; both are drilled by melting ice layers, but improving energy utilization has always been a challenge. In order to improve energy utilization and drilling efficiency, this paper proposes a method for ice drilling with ultrasonic frequency vibration. The mechanism of ultrasonic vibration drilling into ice was analyzed, the solid theoretical foundation for the application of ice melting efficiency under ultrasonic frequency vibration was determined and a series of indoor experiments were conducted. According to experimental data obtained, two conclusions were provided. First, different frequencies have distinct influence on power density, drilling speed and melting rate, and the optimum range excitation frequency for ultrasonic ice drilling is at least 30~32 kHz, under which the ice melting efficiency and drilling speed reached the peak value. Second, ultrasonic assisted drilling was verified to have the ability of improving the efficiency of ice breaking by comparing to thermal drilling under the same power density under 30 kHz. As an environmentally friendly and efficient drilling method, ultrasonic assisted ice drilling has great application prospects in the field of polar exploration. By using Ultrasonic assisted drilling, we demonstrate a strategy for a faster and more efficient drilling method, which is important for humankind

Coherent heteronuclear spin dynamics in an ultracold spin-1 mixture

We report the observation of coherent heteronuclear spin dynamics driven by inter-species spin-spin interaction in an ultracold spinor mixture, which manifests as periodical and well correlated spin oscillations between two atomic species. In particular, we investigate the magnetic field dependence of the oscillations and find a resonance behavior which depends on {\em both} the linear and quadratic Zeeman effects and the spin-dependent interaction. We also demonstrate a unique knob for controlling the spin dynamics in the spinor mixture with species-dependent vector light shifts. Our finds are in agreement with theoretical simulations without any fitting parameters.Comment: 13 pages including the supplementary materia