PHYSICS/BK21 Colloquium[4.14]

  “ Floating objects: Contailerless and contactless

      measurement using levitation techniques “

Ø  Speaker :  Dr. Geun Woo Lee [KRISS]

Ø  Place : Physics Seminar Room (Science Bldg, 3-201)

Ø  Date & Time : Apr, 14 (Wed)  3:00 ~ 4:00 pm

Ø  Abstract

We often observe floating objects, even liquids, in magic show or meditation as an illusion, if it is not happened in space. In fact, this phenomenon can be achieved by levitation techniques using magnetic/ electric field, aerodynamic flow, acoustic field and so on. If we can levitate an object, there are many advantages, for example, no friction, no contamination, homogeneous heating, no container for liquids, and so on. In particular, levitation technique provides containerless environment. Since containers attaining samples cause contamination, unwanted phase formation, hindering from supercooling, and ambiguous signal and background subtraction in experiment, the containerless environment is a big benefit for mechanics, material sciences, biology studies, and particularly high melting temperature materials processing. Thus, levitation techniques have attracted a lot of interest for synthesizing new materials in the high temperature industries (e.g., aerospace, steel, nuclear power, IT).

In this talk, I introduce the principle and application of various levitation techniques, and the status of research activities with the levitation techniques in the world. In particular, non-contact methods will be demonstrated that measures thermodynamic properties (heat capacity, fusion heat, viscosity, surface tension) and structure of liquid metals at a couple of thousand degrees using electrostatic levitation (ESL) technique. Moreover, the potential of this device will be shown with fundamental issues of liquid metals, the relationship between short range order of liquid metals and supercooling phenomenon.

Contact Person : Prof. Yoon  Hee  JEONG (054-279-2078, yhj@postech.ac.kr )