热力学定律 Laws of thermodynamics

此词条暂由彩云小译翻译，未经人工整理和审校，带来阅读不便，请见谅。

The laws of thermodynamics define physical quantities, such as temperature, energy, and entropy, that characterize thermodynamic systems at thermodynamic equilibrium. The laws describe the relationships between these quantities, and form a basis of precluding the possibility of certain phenomena, such as perpetual motion. In addition to their use in thermodynamics, they are important fundamental laws of physics in general, and are applicable in other natural sciences.

The laws of thermodynamics define physical quantities, such as temperature, energy, and entropy, that characterize thermodynamic systems at thermodynamic equilibrium. The laws describe the relationships between these quantities, and form a basis of precluding the possibility of certain phenomena, such as perpetual motion. In addition to their use in thermodynamics, they are important fundamental laws of physics in general, and are applicable in other natural sciences.

热力学定律定义的物理量，如温度，能量，和熵，表征热力学系统在热力学平衡。这些定律描述了这些量之间的关系，并构成了排除某些现象的可能性的基础，例如永动机。除了在热力学中的应用外，它们还是一般物理学的重要基本定律，也适用于其他自然科学。

Thermodynamics has traditionally recognized three fundamental laws, simply named by an ordinal identification, the first law, the second law, and the third law.. In addition, after the first three laws were established, it was recognized that another law, more fundamental to all three, could be stated, which was named the zeroth law.

Thermodynamics has traditionally recognized three fundamental laws, simply named by an ordinal identification, the first law, the second law, and the third law.. In addition, after the first three laws were established, it was recognized that another law, more fundamental to all three, could be stated, which was named the zeroth law.

热力学传统上承认三个基本定律，简单地命名为序数识别，第一定律，第二定律和第三定律。 .此外，在前三个定律建立之后，人们认识到还可以提出另一个对这三个定律更为基本的定律，即第零定律。

The zeroth law of thermodynamics defines thermal equilibrium and forms a basis for the definition of temperature: If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.

The zeroth law of thermodynamics defines thermal equilibrium and forms a basis for the definition of temperature: If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.

热力学第零定律定义了热平衡，并形成了温度定义的基础: 如果两个系统在热平衡中各有一个第三个系统，那么它们就在热平衡中。

The first law of thermodynamics: When energy passes, as work, as heat, or with matter, into or out of a system, the system's internal energy changes in accord with the law of conservation of energy. Equivalently, perpetual motion machines of the first kind (machines that produce work with no energy input) are impossible.

The first law of thermodynamics: When energy passes, as work, as heat, or with matter, into or out of a system, the system's internal energy changes in accord with the law of conservation of energy. Equivalently, perpetual motion machines of the first kind (machines that produce work with no energy input) are impossible.

能量守恒定律: 当能量以功、热或物质的形式进入或离开一个系统时，该系统的内部能量按照能量守恒定律发生变化。同样地，第一类永动机机器(不需要能量输入就能工作的机器)是不可能的。

The second law of thermodynamics: In a natural thermodynamic process, the sum of the entropies of the interacting thermodynamic systems increases. Equivalently, perpetual motion machines of the second kind (machines that spontaneously convert thermal energy into mechanical work) are impossible.

The second law of thermodynamics: In a natural thermodynamic process, the sum of the entropies of the interacting thermodynamic systems increases. Equivalently, perpetual motion machines of the second kind (machines that spontaneously convert thermal energy into mechanical work) are impossible.

热力学第二定律: 在自然热力学过程中，相互作用的热力学系统的熵之和增加。同样地，第二类永动机机器(自发地将热能转化为机械功的机器)是不可能的。

The third law of thermodynamics: The entropy of a system approaches a constant value as the temperature approaches absolute zero. With the exception of non-crystalline solids (glasses) the entropy of a system at absolute zero is typically close to zero.

The third law of thermodynamics: The entropy of a system approaches a constant value as the temperature approaches absolute zero. With the exception of non-crystalline solids (glasses) the entropy of a system at absolute zero is typically close to zero.

热力学第三定律: 当温度接近绝对零度时，系统的熵接近一个常数值。除了非晶体固体(玻璃)以外，系统在绝对零度时的熵通常接近于零。

Additional laws have been suggested, but none of them achieved the generality of the four accepted laws, and are not discussed in standard textbooks.

Additional laws have been suggested, but none of them achieved the generality of the four accepted laws, and are not discussed in standard textbooks.

其他的法律也被提出，但是没有一个法律能够达到这四个公认的法律的普遍性，也没有在标准的教科书中讨论。

Zeroth law

The zeroth law of thermodynamics may be stated in the following form:

The zeroth law of thermodynamics may be stated in the following form:

热力学第零定律可以以下面的形式陈述:

/* Styling for Template:Quote */ .templatequote { overflow: hidden; margin: 1em 0; padding: 0 40px; } .templatequote .templatequotecite {

   line-height: 1.5em;
   /* @noflip */
   text-align: left;
   /* @noflip */
   padding-left: 1.6em;
   margin-top: 0;

}

The law is intended to allow the existence of an empirical parameter, the temperature, as a property of a system such that systems in thermal equilibrium with each other have the same temperature. The law as stated here is compatible with the use of a particular physical body, for example a mass of gas, to match temperatures of other bodies, but does not justify regarding temperature as a quantity that can be measured on a scale of real numbers.

The law is intended to allow the existence of an empirical parameter, the temperature, as a property of a system such that systems in thermal equilibrium with each other have the same temperature. The law as stated here is compatible with the use of a particular physical body, for example a mass of gas, to match temperatures of other bodies, but does not justify regarding temperature as a quantity that can be measured on a scale of real numbers.

该定律旨在允许一个经验参数---- 温度---- 的存在作为一个系统的性质，这样的系统在热平衡中彼此具有相同的温度。这里所说的定律适用于使用特定的物理物体，例如大量的气体，来匹配其他物体的温度，但是并不能证明温度是一个可以用实数来衡量的量。

Though this version of the law is one of the most commonly stated versions, it is only one of a diversity of statements that are labeled as "the zeroth law" by competent writers. Some statements go further so as to supply the important physical fact that temperature is one-dimensional and that one can conceptually arrange bodies in real number sequence from colder to hotter. Perhaps there exists no unique "best possible statement" of the "zeroth law", because there is in the literature a range of formulations of the principles of thermodynamics, each of which call for their respectively appropriate versions of the law.

Though this version of the law is one of the most commonly stated versions, it is only one of a diversity of statements that are labeled as "the zeroth law" by competent writers. Some statements go further so as to supply the important physical fact that temperature is one-dimensional and that one can conceptually arrange bodies in real number sequence from colder to hotter. Perhaps there exists no unique "best possible statement" of the "zeroth law", because there is in the literature a range of formulations of the principles of thermodynamics, each of which call for their respectively appropriate versions of the law.

虽然这个版本的法律是最常见的陈述版本之一，但它只是被称职的作者称为“第零定律”的多种陈述中的一种。有些陈述更进一步，以便提供一个重要的物理事实，即温度是一维的，人们可以在概念上将物体按照实际数字顺序从冷到热排列。也许”第零定律”并不存在唯一的”最佳可能说明” ，因为文献中有一系列热力学原理的表述，每一种表述都要求对热力学原理作出各自适当的说明。

Although these concepts of temperature and of thermal equilibrium are fundamental to thermodynamics and were clearly stated in the nineteenth century, the desire to explicitly number the above law was not widely felt until Fowler and Guggenheim did so in the 1930s, long after the first, second, and third law were already widely understood and recognized. Hence it was numbered the zeroth law. The importance of the law as a foundation to the earlier laws is that it allows the definition of temperature in a non-circular way without reference to entropy, its conjugate variable. Such a temperature definition is said to be 'empirical'.

Although these concepts of temperature and of thermal equilibrium are fundamental to thermodynamics and were clearly stated in the nineteenth century, the desire to explicitly number the above law was not widely felt until Fowler and Guggenheim did so in the 1930s, long after the first, second, and third law were already widely understood and recognized. Hence it was numbered the zeroth law. The importance of the law as a foundation to the earlier laws is that it allows the definition of temperature in a non-circular way without reference to entropy, its conjugate variable. Such a temperature definition is said to be 'empirical'.

虽然这些关于温度和热平衡的概念是热力学的基础，并在19世纪得到了清楚的阐述，但是直到20世纪30年代福勒和古根海姆这样做的时候，人们才普遍感觉到对上述定律进行明确编号的愿望，而这时第一定律、第二定律和第三定律已经得到广泛的理解和认可。因此，它被称为第零定律。该定律作为早期定律基础的重要性在于，它允许以非循环的方式定义温度，而不涉及其共轭变量熵。这样的温度定义被称为“非常准确”。

First law

The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems.

The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems.

能量守恒定律是能量守恒定律的一个版本，适用于热力学系统。

The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed.

The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed.

能量守恒定律指出，孤立系统的总能量是恒定的; 能量可以从一种形式转化为另一种形式，但既不能被创造也不能被破坏。

For a thermodynamic process without transfer of matter, the first law is often formulated

For a thermodynamic process without transfer of matter, the first law is often formulated

对于一个没有物质转移的热力学过程，第一定律通常是公式化的

[math]\displaystyle{ \Delta U_{\rm system} = Q - W }[/math],

[math]\displaystyle{ \Delta U_{\rm system} = Q - W }[/math],

系统 q-w / math,

where ΔU_system denotes the change in the internal energy of a closed system, Q denotes the quantity of energy supplied to the system as heat, and W denotes the amount of thermodynamic work (expressed here with a negative sign) done by the system on its surroundings. (An alternate sign convention not used in this article is to define W as the work done on the system.)

where denotes the change in the internal energy of a closed system, denotes the quantity of energy supplied to the system as heat, and denotes the amount of thermodynamic work (expressed here with a negative sign) done by the system on its surroundings. (An alternate sign convention not used in this article is to define as the work done on the system.)

其中表示一个封闭系统内部能量的变化，表示作为热量提供给该系统的能量的数量，并表示该系统在其周围所做的热力学功的数量(在这里用负号表示)。(本文中没有使用的另一个符号约定是定义在系统上完成的工作。)

In the case of a two-stage thermodynamic cycle of a closed system, which returns to its original state, the heat Q_in supplied to the system in one stage of the cycle, minus the heat Q_out removed from it in the other stage, plus the thermodynamic work added to the system, W_in, equals the thermodynamic work that leaves the system W_out.

In the case of a two-stage thermodynamic cycle of a closed system, which returns to its original state, the heat supplied to the system in one stage of the cycle, minus the heat removed from it in the other stage, plus the thermodynamic work added to the system, , equals the thermodynamic work that leaves the system .

对于一个封闭系统的两级热力学循环，它返回到原始状态，在循环的一个阶段提供给系统的热量减去在另一个阶段从系统中移除的热量，加上增加到系统中的热力学功，等于离开系统的热力学功。

[math]\displaystyle{ \Delta U_{\rm system\,(full\,cycle)}=0 }[/math]

[math]\displaystyle{ \Delta U_{\rm system\,(full\,cycle)}=0 }[/math]

0 / math

hence, for a full cycle,

hence, for a full cycle,

因此，一个完整的循环,

Or [math]\displaystyle{ Q - W = Q_{\rm in} - Q_{\rm out} - (W_{\rm out} - W_{\rm in}) =0 }[/math].

Or [math]\displaystyle{ Q - W = Q_{\rm in} - Q_{\rm out} - (W_{\rm out} - W_{\rm in}) =0 }[/math].

Or [math]\displaystyle{ Q - W = Q_{\rm in} - Q_{\rm out} - (W_{\rm out} - W_{\rm in}) =0 }[/math].

For the particular case of a thermally isolated system (adiabatically isolated), the change of the internal energy of an adiabatically isolated system can only be the result of the work added to the system, because the adiabatic assumption is: Q = 0.

For the particular case of a thermally isolated system (adiabatically isolated), the change of the internal energy of an adiabatically isolated system can only be the result of the work added to the system, because the adiabatic assumption is: 0}}.

对于绝热孤立热孤立系统的特殊情况，绝热孤立系统内能的变化只能是系统所做功的结果，因为绝热假设是: 0}。

[math]\displaystyle{ \Delta U_{\rm system} = U_{\rm final} - U_{\rm initial} = W_{\rm in} - W_{\rm out} }[/math]

[math]\displaystyle{ \Delta U_{\rm system} = U_{\rm final} - U_{\rm initial} = W_{\rm in} - W_{\rm out} }[/math]

[math]\displaystyle{ \Delta U_{\rm system} = U_{\rm final} - U_{\rm initial} = W_{\rm in} - W_{\rm out} }[/math]

For processes that include transfer of matter, a further statement is needed: 'With due account of the respective fiducial reference states of the systems, when two systems, which may be of different chemical compositions, initially separated only by an impermeable wall, and otherwise isolated, are combined into a new system by the thermodynamic operation of removal of the wall, then

For processes that include transfer of matter, a further statement is needed: 'With due account of the respective fiducial reference states of the systems, when two systems, which may be of different chemical compositions, initially separated only by an impermeable wall, and otherwise isolated, are combined into a new system by the thermodynamic operation of removal of the wall, then

对于包括物质转移的过程，需要进一步的陈述: ‘在适当考虑了各个系统的基准参考状态后，当两个系统---- 它们可能是不同的化学成分，最初只是被不透水的墙隔开，或者是被隔离---- 通过移除热力学操作结合成一个新的系统，那么

[math]\displaystyle{ U_{\rm system} = U_1 + U_2 }[/math],

[math]\displaystyle{ U_{\rm system} = U_1 + U_2 }[/math],

数学 u + u 2 / math,

where U_system denotes the internal energy of the combined system, and U₁ and U₂ denote the internal energies of the respective separated systems.'

where denotes the internal energy of the combined system, and and denote the internal energies of the respective separated systems.'

其中表示组合系统的内能，并表示各自分离系统的内能

The First Law encompasses several principles:

The First Law encompasses several principles:

第一定律包括以下几个原则:

• The law of conservation of energy.

This states that energy can be neither created nor destroyed. However, energy can change forms, and energy can flow from one place to another. A particular consequence of the law of conservation of energy is that the total energy of an isolated system does not change.

This states that energy can be neither created nor destroyed. However, energy can change forms, and energy can flow from one place to another. A particular consequence of the law of conservation of energy is that the total energy of an isolated system does not change.

这种观点认为能量既不能被创造也不能被摧毁。然而，能量可以改变形式，能量可以从一个地方流动到另一个地方。能量守恒定律的一个特殊结果是，孤立系统的总能量不变。

• The concept of internal energy and its relationship to temperature.

If a system has a definite temperature, then its total energy has three distinguishable components. If the system is in motion as a whole, it has kinetic energy. If the system as a whole is in an externally imposed force field (e.g. gravity), it has potential energy relative to some reference point in space. Finally, it has internal energy, which is a fundamental quantity of thermodynamics. The establishment of the concept of internal energy distinguishes the first law of thermodynamics from the more general law of conservation of energy.

If a system has a definite temperature, then its total energy has three distinguishable components. If the system is in motion as a whole, it has kinetic energy. If the system as a whole is in an externally imposed force field (e.g. gravity), it has potential energy relative to some reference point in space. Finally, it has internal energy, which is a fundamental quantity of thermodynamics. The establishment of the concept of internal energy distinguishes the first law of thermodynamics from the more general law of conservation of energy.

如果一个系统有一定的温度，那么它的总能量有三个可区分的组成部分。如果系统作为一个整体在运动，它就有动能。如果系统作为一个整体处于外部施加的力场中(例如:。重力) ，它相对于空间中某个参考点有势能。最后，它有内能，这是热力学的基本量。内能概念的建立使能量守恒定律不同于更一般的能量守恒定律。

[math]\displaystyle{ E_{\rm total} = \mathrm{KE}_{\rm system} + \mathrm{PE}_{\rm system} + U_{\rm system} }[/math]

[math]\displaystyle{ E_{\rm total} = \mathrm{KE}_{\rm system} + \mathrm{PE}_{\rm system} + U_{\rm system} }[/math]

[math]\displaystyle{ E_{\rm total} = \mathrm{KE}_{\rm system} + \mathrm{PE}_{\rm system} + U_{\rm system} }[/math]

The internal energy of a substance can be explained as the sum of the diverse kinetic energies of the erratic microscopic motions of its constituent atoms, and of the potential energy of interactions between them. Those microscopic energy terms are collectively called the substance's internal energy, U, and are accounted for by macroscopic thermodynamic property. The total of the kinetic energies of microscopic motions of the constituent atoms increases as the system's temperature increases; this assumes no other interactions at the microscopic level of the system such as chemical reactions, potential energy of constituent atoms with respect to each other.

The internal energy of a substance can be explained as the sum of the diverse kinetic energies of the erratic microscopic motions of its constituent atoms, and of the potential energy of interactions between them. Those microscopic energy terms are collectively called the substance's internal energy, , and are accounted for by macroscopic thermodynamic property. The total of the kinetic energies of microscopic motions of the constituent atoms increases as the system's temperature increases; this assumes no other interactions at the microscopic level of the system such as chemical reactions, potential energy of constituent atoms with respect to each other.

物质的内能可以解释为其组成原子不规则微观运动的不同动能和它们之间相互作用的势能的总和。这些微观能量项统称为物质的内能，并由宏观热力学性质列表解释。组成原子的微观运动动能的总和随着系统温度的升高而增加; 这在系统的微观层次上没有其他的相互作用，例如化学反应、组成原子相互间的势能。

• Work is a process of transferring energy to or from a system in ways that can be described by macroscopic mechanical forces exerted by factors in the surroundings, outside the system. Examples are an externally driven shaft agitating a stirrer within the system, or an externally imposed electric field that polarizes the material of the system, or a piston that compresses the system. Unless otherwise stated, it is customary to treat work as occurring without its dissipation to the surroundings. Practically speaking, in all natural process, some of the work is dissipated by internal friction or viscosity. The work done by the system can come from its overall kinetic energy, from its overall potential energy, or from its internal energy.

For example, when a machine (not a part of the system) lifts a system upwards, some energy is transferred from the machine to the system. The system's energy increases as work is done on the system and in this particular case, the energy increase of the system is manifested as an increase in the system's gravitational potential energy. Work added to the system increases the Potential Energy of the system:

For example, when a machine (not a part of the system) lifts a system upwards, some energy is transferred from the machine to the system. The system's energy increases as work is done on the system and in this particular case, the energy increase of the system is manifested as an increase in the system's gravitational potential energy. Work added to the system increases the Potential Energy of the system:

例如，当一台机器(不是系统的一部分)将一个系统向上提升时，一些能量就会从机器转移到系统。系统的能量随着系统所做功的增加而增加，在这种特殊的情况下，系统的能量增加表现为系统的重力位能量的增加。加入系统的功增加了系统的势能:

[math]\displaystyle{ W = \Delta \mathrm{PE}_{\rm system} }[/math]

[math]\displaystyle{ W = \Delta \mathrm{PE}_{\rm system} }[/math]

[math]\displaystyle{ W = \Delta \mathrm{PE}_{\rm system} }[/math]

Or in general, the energy added to the system in the form of work can be partitioned to kinetic, potential or internal energy forms:

Or in general, the energy added to the system in the form of work can be partitioned to kinetic, potential or internal energy forms:

或者一般来说，以功的形式加到系统中的能量可以分为动能、势能或内能:

[math]\displaystyle{ W = \Delta \mathrm{KE}_{\rm system}+\Delta \mathrm{PE}_{\rm system}+\Delta U_{\rm system} }[/math]

[math]\displaystyle{ W = \Delta \mathrm{KE}_{\rm system}+\Delta \mathrm{PE}_{\rm system}+\Delta U_{\rm system} }[/math]

[math]\displaystyle{ W = \Delta \mathrm{KE}_{\rm system}+\Delta \mathrm{PE}_{\rm system}+\Delta U_{\rm system} }[/math]

• When matter is transferred into a system, that masses' associated internal energy and potential energy are transferred with it.

[math]\displaystyle{ \left( u \,\Delta M \right)_{\rm in} = \Delta U_{\rm system} }[/math]

[math]\displaystyle{ \left( u \,\Delta M \right)_{\rm in} = \Delta U_{\rm system} }[/math]

在 Delta u { system } / math 中的 math left (u，Delta m right)

where u denotes the internal energy per unit mass of the transferred matter, as measured while in the surroundings; and ΔM denotes the amount of transferred mass.

where denotes the internal energy per unit mass of the transferred matter, as measured while in the surroundings; and denotes the amount of transferred mass.

其中表示被转移物质单位质量的内部能量，在周围环境中测量; 并表示被转移物质的数量。

• The flow of heat is a form of energy transfer.

Heating is a natural process of moving energy to or from a system other than by work or the transfer of matter. Direct passage of heat is only from a hotter to a colder system.

Heating is a natural process of moving energy to or from a system other than by work or the transfer of matter. Direct passage of heat is only from a hotter to a colder system.

加热是一个自然的过程，除了通过功或物质的转移，能量进出一个系统。热量的直接通过只是从一个较热的系统到一个较冷的系统。

If the system has rigid walls that are impermeable to matter, and consequently energy cannot be transferred as work into or out from the system, and no external long-range force field affects it that could change its internal energy, then the internal energy can only be changed by the transfer of energy as heat:

If the system has rigid walls that are impermeable to matter, and consequently energy cannot be transferred as work into or out from the system, and no external long-range force field affects it that could change its internal energy, then the internal energy can only be changed by the transfer of energy as heat:

如果系统具有不透物质的刚性壁，因此能量不能作为功传入或传出系统，而且没有外部的长程力场影响系统以改变其内部能量，那么内部能量只能通过作为热的能量传递来改变:

[math]\displaystyle{ \Delta U_{\rm system}=Q }[/math]

[math]\displaystyle{ \Delta U_{\rm system}=Q }[/math]

系统的 q / math

where Q denotes the amount of energy transferred into the system as heat.

where denotes the amount of energy transferred into the system as heat.

其中表示作为热量传递到系统中的能量。

Combining these principles leads to one traditional statement of the first law of thermodynamics: it is not possible to construct a machine which will perpetually output work without an equal amount of energy input to that machine. Or more briefly, a perpetual motion machine of the first kind is impossible.

Combining these principles leads to one traditional statement of the first law of thermodynamics: it is not possible to construct a machine which will perpetually output work without an equal amount of energy input to that machine. Or more briefly, a perpetual motion machine of the first kind is impossible.

将这些原理结合在一起，就产生了能量守恒定律的一个传统陈述: 不可能建造一台机器，在没有相同能量输入的情况下，它将永久地输出工作。或者更简单地说，第一种永动机是不可能的。

Second law

The second law of thermodynamics indicates the irreversibility of natural processes and, in many cases, the tendency of natural processes to lead towards spatial homogeneity of matter and energy, and especially of temperature. It can be formulated in a variety of interesting and important ways.

The second law of thermodynamics indicates the irreversibility of natural processes and, in many cases, the tendency of natural processes to lead towards spatial homogeneity of matter and energy, and especially of temperature. It can be formulated in a variety of interesting and important ways.

热力学第二定律表明了自然过程的不可逆性，在许多情况下，自然过程的趋势导致物质和能量的空间同质化，特别是温度的同质化。它可以用各种有趣而重要的方式来表达。

It implies the existence of a quantity called the entropy of a thermodynamic system. In terms of this quantity it implies that

It implies the existence of a quantity called the entropy of a thermodynamic system. In terms of this quantity it implies that

它暗示了一个叫做热力学系统熵的量的存在。就这个数量而言，它意味着

/* Styling for Template:Quote */ .templatequote { overflow: hidden; margin: 1em 0; padding: 0 40px; } .templatequote .templatequotecite {

   line-height: 1.5em;
   /* @noflip */
   text-align: left;
   /* @noflip */
   padding-left: 1.6em;
   margin-top: 0;

}

The second law is applicable to a wide variety of processes, reversible and irreversible. All natural processes are irreversible. Reversible processes are a useful and convenient theoretical fiction, but do not occur in nature.

The second law is applicable to a wide variety of processes, reversible and irreversible. All natural processes are irreversible. Reversible processes are a useful and convenient theoretical fiction, but do not occur in nature.

第二定律适用于可逆和不可逆的各种过程。所有的自然过程都是不可逆的。可逆过程是一个有用的和方便的理论虚构，但不发生在自然界。

A prime example of irreversibility is in the transfer of heat by conduction or radiation. It was known long before the discovery of the notion of entropy that when two bodies initially of different temperatures come into thermal connection, then heat always flows from the hotter body to the colder one.

A prime example of irreversibility is in the transfer of heat by conduction or radiation. It was known long before the discovery of the notion of entropy that when two bodies initially of different temperatures come into thermal connection, then heat always flows from the hotter body to the colder one.

不可逆性的一个主要例子是热传导或辐射的传递。早在熵的概念被发现之前，人们就已经知道，当两个最初温度不同的物体进入热连接时，热量总是从较热的物体流向较冷的物体。

The second law tells also about kinds of irreversibility other than heat transfer, for example those of friction and viscosity, and those of chemical reactions. The notion of entropy is needed to provide that wider scope of the law.

The second law tells also about kinds of irreversibility other than heat transfer, for example those of friction and viscosity, and those of chemical reactions. The notion of entropy is needed to provide that wider scope of the law.

第二定律也告诉我们除了热传递之外的不可逆性，例如摩擦力和粘度，以及化学反应。熵的概念是需要提供更广泛的法律范围。

According to the second law of thermodynamics, in a theoretical and fictive reversible heat transfer, an element of heat transferred, δQ, is the product of the temperature (T), both of the system and of the sources or destination of the heat, with the increment (dS) of the system's conjugate variable, its entropy (S)

According to the second law of thermodynamics, in a theoretical and fictive reversible heat transfer, an element of heat transferred, δQ, is the product of the temperature (T), both of the system and of the sources or destination of the heat, with the increment (dS) of the system's conjugate variable, its entropy (S)

根据热力学第二定律理论，在理论上和虚构的可逆传热中，传热元件 q 是系统和热源或热目的地的温度(t)与系统共轭变量 s 的增量(dS)的乘积

[math]\displaystyle{ \delta Q = T\,dS\, . }[/math]

[math]\displaystyle{ \delta Q = T\,dS\, . }[/math]

数学 delta q t ，dS ，. / math

Entropy may also be viewed as a physical measure of the lack of physical information about the microscopic details of the motion and configuration of a system, when only the macroscopic states are known. This lack of information is often described as disorder on a microscopic or molecular scale. The law asserts that for two given macroscopically specified states of a system, there is a quantity called the difference of information entropy between them. This information entropy difference defines how much additional microscopic physical information is needed to specify one of the macroscopically specified states, given the macroscopic specification of the other – often a conveniently chosen reference state which may be presupposed to exist rather than explicitly stated. A final condition of a natural process always contains microscopically specifiable effects which are not fully and exactly predictable from the macroscopic specification of the initial condition of the process. This is why entropy increases in natural processes – the increase tells how much extra microscopic information is needed to distinguish the final macroscopically specified state from the initial macroscopically specified state.

Entropy may also be viewed as a physical measure of the lack of physical information about the microscopic details of the motion and configuration of a system, when only the macroscopic states are known. This lack of information is often described as disorder on a microscopic or molecular scale. The law asserts that for two given macroscopically specified states of a system, there is a quantity called the difference of information entropy between them. This information entropy difference defines how much additional microscopic physical information is needed to specify one of the macroscopically specified states, given the macroscopic specification of the other – often a conveniently chosen reference state which may be presupposed to exist rather than explicitly stated. A final condition of a natural process always contains microscopically specifiable effects which are not fully and exactly predictable from the macroscopic specification of the initial condition of the process. This is why entropy increases in natural processes – the increase tells how much extra microscopic information is needed to distinguish the final macroscopically specified state from the initial macroscopically specified state.

当只知道宏观状态时，熵也可以被看作是对系统运动和构型的微观细节缺乏物理信息的一种物理度量。这种信息的缺乏常常被描述为微观或分子尺度上的无序。该定律声称，对于一个系统的两个给定的宏观特定状态，它们之间存在一个被称为熵差的量。这种熵的差异定义了需要多少额外的微观物理信息来指定一个宏观指定的状态，给定另一个宏观指定-往往是一个方便选择的参考状态，可能预先假定存在，而不是明确说明。一个自然过程的最终条件总是包含着微观上特定的影响，从过程初始条件的宏观规定来看，这些影响是不能完全和准确地预测的。这就是为什么熵在自然过程中增加——熵的增加告诉我们需要多少额外的微观信息来区分最终的宏观指定状态和最初的宏观指定状态。

Third law

The third law of thermodynamics is sometimes stated as follows:

The third law of thermodynamics is sometimes stated as follows:

热力学第三定律有时候是这样说的:

The entropy of a perfect crystal of any pure substance approaches zero as the temperature approaches absolute zero.

The entropy of a perfect crystal of any pure substance approaches zero as the temperature approaches absolute zero.

当温度接近绝对零度时，任何纯物质的完美晶体的熵接近零。

At zero temperature the system must be in a state with the minimum thermal energy. This statement holds true if the perfect crystal has only one state with minimum energy. Entropy is related to the number of possible microstates according to:

At zero temperature the system must be in a state with the minimum thermal energy. This statement holds true if the perfect crystal has only one state with minimum energy. Entropy is related to the number of possible microstates according to:

在零温时，系统必须处于热能最小的状态。如果完美晶体只有一个能量最小的状态，这种说法也成立。熵与可能的微观状态数量有关，依据是:

[math]\displaystyle{ S = k_{\mathrm B}\, \mathrm{ln}\, \Omega }[/math]

[math]\displaystyle{ S = k_{\mathrm B}\, \mathrm{ln}\, \Omega }[/math]

数学知识，数学知识，欧米茄 / 数学

Where S is the entropy of the system, k_B Boltzmann's constant, and Ω the number of microstates (e.g. possible configurations of atoms). At absolute zero there is only 1 microstate possible (Ω=1 as all the atoms are identical for a pure substance and as a result all orders are identical as there is only one combination) and ln(1) = 0.

Where S is the entropy of the system, k_B Boltzmann's constant, and Ω the number of microstates (e.g. possible configurations of atoms). At absolute zero there is only 1 microstate possible (Ω=1 as all the atoms are identical for a pure substance and as a result all orders are identical as there is only one combination) and ln(1) = 0.

其中 s 是系统的熵，k 子 b / 子 Boltzmann 常数，以及微观状态的数目(例如:。可能的原子构型)。在绝对零度下只有1个微态可能(1，因为纯物质的所有原子都是相同的，所以所有的顺序都是相同的，因为只有一个组合)和 ln (1)0。

A more general form of the third law that applies to a system such as a glass that may have more than one minimum microscopically distinct energy state, or may have a microscopically distinct state that is "frozen in" though not a strictly minimum energy state and not strictly speaking a state of thermodynamic equilibrium, at absolute zero temperature:

A more general form of the third law that applies to a system such as a glass that may have more than one minimum microscopically distinct energy state, or may have a microscopically distinct state that is "frozen in" though not a strictly minimum energy state and not strictly speaking a state of thermodynamic equilibrium, at absolute zero temperature:

第三定律的一个更一般的形式，适用于一个系统，如玻璃，可能有一个以上的最低微观上截然不同的能量状态，或可能有一个微观上截然不同的状态是“冻结在” ，虽然不是一个严格的最低能量状态，严格来说不是一个热力学平衡状态，在绝对零度:

The entropy of a system approaches a constant value as the temperature approaches zero.

The entropy of a system approaches a constant value as the temperature approaches zero.

当温度趋近于零时，系统的熵趋近于一个常数值。

The constant value (not necessarily zero) is called the residual entropy of the system.

The constant value (not necessarily zero) is called the residual entropy of the system.

这个常量值(不一定是零)称为系统的余熵。

History

See also: Philosophy of thermal and statistical physics

Circa 1797, Count Rumford (born Benjamin Thompson) showed that endless mechanical action can generate indefinitely large amounts of heat from a fixed amount of working substance thus challenging the caloric theory of heat, which held that there would be a finite amount of caloric heat/energy in a fixed amount of working substance. The first established thermodynamic principle, which eventually became the second law of thermodynamics, was formulated by Sadi Carnot in 1824. By 1860, as formalized in the works of those such as Rudolf Clausius and William Thomson, two established principles of thermodynamics had evolved, the first principle and the second principle, later restated as thermodynamic laws. By 1873, for example, thermodynamicist Josiah Willard Gibbs, in his memoir Graphical Methods in the Thermodynamics of Fluids, clearly stated the first two absolute laws of thermodynamics. Some textbooks throughout the 20th century have numbered the laws differently. In some fields removed from chemistry, the second law was considered to deal with the efficiency of heat engines only, whereas what was called the third law dealt with entropy increases. Directly defining zero points for entropy calculations was not considered to be a law. Gradually, this separation was combined into the second law and the modern third law was widely adopted.

Circa 1797, Count Rumford (born Benjamin Thompson) showed that endless mechanical action can generate indefinitely large amounts of heat from a fixed amount of working substance thus challenging the caloric theory of heat, which held that there would be a finite amount of caloric heat/energy in a fixed amount of working substance. The first established thermodynamic principle, which eventually became the second law of thermodynamics, was formulated by Sadi Carnot in 1824. By 1860, as formalized in the works of those such as Rudolf Clausius and William Thomson, two established principles of thermodynamics had evolved, the first principle and the second principle, later restated as thermodynamic laws. By 1873, for example, thermodynamicist Josiah Willard Gibbs, in his memoir Graphical Methods in the Thermodynamics of Fluids, clearly stated the first two absolute laws of thermodynamics. Some textbooks throughout the 20th century have numbered the laws differently. In some fields removed from chemistry, the second law was considered to deal with the efficiency of heat engines only, whereas what was called the third law dealt with entropy increases. Directly defining zero points for entropy calculations was not considered to be a law. Gradually, this separation was combined into the second law and the modern third law was widely adopted.

大约在1797年，计数拉姆福德(出生的本杰明·汤普森，伦福德伯爵)显示，无休止的机械作用可以产生无限大量的热量从一个固定数量的工作物质，从而挑战热量的热量理论，其中认为有一个固定数量的工作物质热量 / 能量有限数量的热量。第一个建立的热力学原理，最终成为热力学第二定律，是由 Sadi Carnot 在1824年制定的。到了1860年，正如鲁道夫 · 克劳修斯和威廉 · 汤姆森等人的著作所正式确定的那样，两个既定的热力学原理已经形成---- 第一原理和第二原理，后来重述为热力学定律。例如，到了1873年，热力学家约西亚·威拉德·吉布斯在他的回忆录《流体热力学的图形方法》中明确指出了前两个绝对热力学定律。整个20世纪的一些教科书对法律有不同的编号。在一些与化学无关的领域，第二定律被认为仅仅处理热机的效率问题，而所谓的第三定律则处理熵的增加问题。为熵计算直接定义零点不被认为是一个定律。这种分离逐渐形成了第二定律，现代第三定律被广泛采用。

See also

• Chemical thermodynamics

• Conservation law

• Entropy production

• Ginsberg's theorem

• Heat death of the universe

• H-theorem

• Laws of science

• Onsager reciprocal relations (sometimes described as a fourth law of thermodynamics)

• Statistical mechanics

• Table of thermodynamic equations

Further reading

• Atkins, Peter (2007). Four Laws That Drive the Universe. OUP Oxford.
  • Goldstein, Martin & Inge F. (1993). The Refrigerator and the Universe. Harvard Univ. Press.

    
    

    External links

    • In Our Time: Perpetual Motion, BBC discussion about the Laws, with Ruth Gregory, Frank Close and Steven Bramwell, hosted by Melvyn Bragg, first broadcast 24 September 2015.

    Category:Scientific laws

    类别: 科学定律

    
    

    This page was moved from wikipedia:en:Laws of thermodynamics. Its edit history can be viewed at 热力学定律/edithistory