High-speed observation of the piston effect near the gas-liquid critical point.
High-speed observation of the piston effect near the gas-liquid critical point.
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DOI：
10.1103/physreve.74.010101
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发表时间：
2006-02
期刊：
影响因子：
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通讯作者：
Y. Miura;S. Yoshihara;M. Ohnishi;K. Honda;M. Matsumoto;J. Kawai;M. Ishikawa;Hiroto Kobayashi;A. Onuki
中科院分区：
文献类型：
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作者：
Y. Miura;S. Yoshihara;M. Ohnishi;K. Honda;M. Matsumoto;J. Kawai;M. Ishikawa;Hiroto Kobayashi;A. Onuki
我们用超灵敏干涉仪研究了近临界流体在声时间尺度上的绝热变化。由非常弱的连续加热发出的声音在其前沿引起逐步绝热变化，密度变化10(-7)g/cm(3)量级，温度变化10(-5)K量级。在加热器上输入很小的热输入会产生宽度为10微米的短声脉冲，这些脉冲在穿过单元并与边界相互作用时被加宽。在临界点附近，脉冲展宽增强。我们还从理论上研究了加热器是如何发出声音的，以及施加的热量是如何转化为机械功的。我们的预测与我们的数据很好地吻合。
We investigated adiabatic changes in a near-critical fluid on acoustic time scales using an ultrasensitive interferometer. A sound emitted by very weak continuous heating caused a stepwise adiabatic change at its front with a density change of order 10(-7) g/cm(3) and a temperature change of order 10(-5) K. Very small heat inputs at a heater produced short acoustic pulses with width of order 10 micros, which were broadened as they moved through the cell and interacted with the boundaries. The pulse broadening became enhanced near the critical point. We also examined theoretically how sounds are emitted from a heater and how applied heat is transformed into mechanical work. Our predictions agree well with our data.