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A dilatometer is a scientific instrument that measures volume changes caused by a physical or chemical process. A familiar application of a dilatometer is the mercury-in-glass thermometer, in which the change in volume of the liquid column is read from a graduated scale. Because mercury has a fairly constant rate of expansion over normal temperature ranges, the volume changes are directly related to temperature. ==Applications== Dilatometers have been used in the fabrication of metallic alloys, compressed and sintered refractory compounds, glasses, ceramic products, composite materials, and plastics.〔Hans Lehmann, refuge Gatzke '' Dilatometrie and differential thermal analysis for the evaluation of processes ''? ? , 1956.〕 Dilatometry is also used to monitor the progress of chemical reactions, particularly those displaying a substantial molar volume change (e.g., polymerisation). A specific example is the rate of phase changes. Another common application of a dilatometer is the measurement of thermal expansion. The thermal expansivity is defined as: and is an important engineering parameter. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「dilatometer」の詳細全文を読む スポンサード リンク
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