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An isochoric process, also called a constant-volume process, an isovolumetric process, or an isometric process, is a thermodynamic process during which the volume of the closed system undergoing such a process remains constant. An isochoric process is exemplified by the heating or the cooling of the contents of a sealed, inelastic container: The thermodynamic process is the addition or removal of heat; the isolation of the contents of the container establishes the closed system; and the inability of the container to deform imposes the constant-volume condition. The isochoric process here should be a quasi-static process. ==Formalism== An isochoric thermodynamic process is characterized by constant volume, i.e., . The process does no pressure-volume work, since such work is defined by :, where ''P'' is pressure. The sign convention is such that positive work is performed by the system on the environment. If the process is not quasi-static, the work can perhaps be done in a volume constant thermodynamic process.〔https://www.physicsforums.com/threads/if-gas-volume-remains-constant-it-can-does-work-to-others.765131/〕 For a reversible process, the first law of thermodynamics gives the change in the system's internal energy: : Replacing work with a change in volume gives : Since the process is isochoric, , the previous equation now gives : Using the definition of specific heat capacity at constant volume, :, : Integrating both sides yields : Where is the specific heat capacity at constant volume, is the initial temperature and is the final temperature. We conclude with: : On a pressure volume diagram, an isochoric process appears as a straight vertical line. Its thermodynamic conjugate, an isobaric process would appear as a straight horizontal line. 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「Isochoric process」の詳細全文を読む スポンサード リンク
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