| Budget Amount *help |
¥10,690,000 (Direct Cost: ¥10,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2007: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2006: ¥9,000,000 (Direct Cost: ¥9,000,000)
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| Research Abstract |
Matters obtain the momentum when the irradiate light is scatted by matters. This momentum is called radiation pressure of light. In the present study, we develop the instrument to evaluate surface tension using radiation pressure. In particular, vapor-liquid surface at around vapor-liquid critical point is very sensitive to perturbations. Such a sensitive interface or surface will be deformed by the radiation pressure of light, and the degree of deformation will be used to evaluate the surface tension.
We have developed the instrument to construct optical cell for high-pressure condition, optics, and detection system. Windows of the cell was made of sapphire. Temperature was controlled by a set of a ND controller, heaters, and a thermocouple, and its fluctuation was within 0.1 degree. Pressure was monitored by a strain gauge. Important points for the present study are in the following. i) interface and/or surface should be observed at 90 degree against incident laser at high pressure condition, ii) laser has good TEM_<00> mode, iii) laser output is variable and its power is greater than 5W. By using laser, optics, and cell, we can develop the system to observe vapor-liquid interface at around vapor-liquid critical point. However, a problem happens. That is, the laser incidence generates babbles in fluid, which disturb the observation of interface. Since the laser wavelength is 532 nm, the laser light is not absorbed by CO_2, because CO_2 dose not have absorption band of electronic transition in visible region. It seems that these babbles are generated by energy transfer from laser to fluid via inelastic scattering such as Raman scattering. As a result, the fluid heated by transferred energy most probably generates bubbles. We tried to diminish the bubble by changing the fluid temperature, but the situation was not changed. In near future, further changes of thermodynamic states and/or the use of Raman no active fluid will be needed to overcome this bubble problem.
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