热力学基础

温度 | Temperature

计量单位 | Scales

• Celsius scale
• Fahrenheit scale
• Kelvin scale
• Rankine scale

第零定律 | Zeroth Law of Thermodynamic

If two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other.

过程与循环 | Processes and Cycle

• Any change that a system undergoes from one equilibrium state to another is called a process.
• A series of states through which a system passes during a process is called the path.
• A system is said to have undergone a cycle if it returns to its initial state at the end of the process.

一些常见过程别称

• Constant temperature process - Isothermal process
• Constant pressure process - Isobaric process
• Constant volume process - Isometric process or isochoric process
• Adiabatic Process - no heat is transferred.
• If the process happens so quickly that there is no time to transfer heat,
• or If a system is very well insulated from its surroundings.
• Polytropic process - occurs with an interchange of both heat and work between the inside and outside.

系统与边界 | Systems and Boundary

• System: a quantity of matter or a region in space chosen for study.
• Surrounding: the mass or region outside the system.
• Boundary: the real or imaginary surface that separates the system from its surroundings.

理想气体法则 | Ideal Gas Laws

Boyle’s Law (1662)

Constant temperature

Charles' law (1780) (Joseph Louis Gay-Lussac in 1802)

Constant pressure

Combined ideal gas law

比热容 | Specific heat capacity

需要记忆的值：

定压比热：，定容比热：

三者关系：

内能和热含量 | Internal Energy and Enthalpy

多方过程 | Polytropic Process

例题

A piston–cylinder device initially contains 0.7 m³ of air at 100 kPa and 80°C. The air is now compressed to 0.1 m³ in such a way that the temperature inside the cylinder remains constant. Determine the work done during this process.

知识点：边界移动功

此题中温度不变，使用公式：

将 代入上式，得

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