埃米尔·克拉佩龙Benoît Paul Émile Clapeyron

埃米尔·克拉佩龙 出生于革命月 Pluviose 的第 7 天，即 1 月 26 日。他在巴黎综合理工学院接受教育，于 1818 年毕业。然后他去了巴黎矿业学院，在那里与他的朋友 Gabriel 加布里尔·拉梅 一起接受工程师培训。

克拉佩龙 和 加布里尔·拉梅 于 1820 年一起去了俄罗斯。俄罗斯的亚历山大一世组建了一支工程师团队来改善俄罗斯的道路和桥梁，他求助于法国来提供教学和领导新组建团队的专门知识。克拉佩龙 和 加布里尔·拉梅 去了圣彼得堡，那里已经建立了公共工程学校，他们教授纯数学和应用数学。他们除了讲课之外，还参与领导建设工作。

克拉佩龙 和 加布里尔·拉梅 在俄罗斯待了 10 年。在那段时间里，他们在许多期刊上发表了联合的数学和工程著作。他们在 1830 年革命后离开，当时他们的政治观点让他们感到不受欢迎。他们回到法国时，铁路刚刚开始建设，但早期的尝试在经济上失败了。他们有远见，看到了铁路的巨大未来，资金开始投入到与铁路发展相关的工程问题的研究中。

克拉佩龙 提议修建一条从巴黎到圣 索菲·热尔曼 的铁路线，并为该项目寻求资金。然而，在获得资金之前，他被提供了圣艾蒂安矿业学校的讲席。1835 年，从巴黎到圣 索菲·热尔曼 的线路建设获得授权，克拉佩龙 和 加布里尔·拉梅 被任命负责该项目。加布里尔·拉梅 在他们开始工作后不久被提供了巴黎综合理工学院的物理学讲席，克拉佩龙 则留下来领导这项事业。

1836年，专门设计蒸汽机车的克拉佩龙前往英格兰，安排建造一些专用机车。克拉佩龙联系了最著名的机车制造商史蒂文森，但史蒂文森觉得克拉佩龙的设计太难，拒绝了合同。克拉佩龙随后联系了夏普，塞缪尔·罗伯茨公司，这是一家制造铁路机车的公司，是最早应用互换零件的公司之一。回到法国后，克拉佩龙继续他的项目，将活动扩展到金属桥梁的设计。

1844年，克拉佩龙被任命为桥梁与道路学院的教授，然后在1848年，他当选为巴黎科学院。他在多个委员会为科学院服务，特别是担任颁发力学奖的委员会成员。他还任职于调查苏伊士运河建设的委员会，以及考虑如何在海军中使用蒸汽机的委员会。

1834年，克拉佩龙借助图形表示，以解析方式表达了萨迪·卡诺关于热的思想。在克拉佩龙的论文之前，萨迪·卡诺的工作几乎不为人知，该论文以数学公式给出了卡诺循环。当克拉佩龙的工作对热力学第二定律的重要性变得明显时，它对开尔文和鲁道夫·克劳修斯产生了重要影响。克拉佩龙关系，一个确定液体汽化热的微分方程，以他的名字命名。

Émile Clapeyron was born on the 7th day of the Revolutionary month Pluviose, which corresponds to 26th January. He was educated at the École Polytechnique from which he graduated in 1818. He then went to the École des Mines where he trained as an engineer along with his friend Gabriel Lamé.

Clapeyron and Lamé went together to Russia in 1820. Alexander I of Russia had set up a team of engineers to improve the roads and bridges of Russia and he turned to France to provide the expertise in teaching and leading the newly formed teams. Clapeyron and Lamé went to St Petersburg where the École des Travaux Publics had been set up and these they taught both pure and applied mathematics. They both also engaged in leading the construction work as well as lecturing.

Both Clapeyron and Lamé remained in Russia for 10 years. During that time they published joint mathematical and engineering work in a number of journals. They left following the revolution of 1830 when their political views made them feel unwelcome. They returned to France at a time when railways were just beginning to be constructed but the early ventures had been economic failures. They had the vision to see the great future in railways and money began to go into a study of engineering problems associated with their development.

Clapeyron proposed a railway line from Paris to St Germain and sought funding for the project. However, before funding was obtained he was offered a chair at the École des Mineurs in St Étienne. In 1835 the construction of the line from Paris to St Germain was authorised and Clapeyron and Lamé were put in charge of the project. Lamé was offered the chair of physics at the École Polytechnique shortly after they began their work and Clapeyron was left to head the venture.

In 1836 Clapeyron, who specialised in designing steam locomotives, went to England to arrange for the building of some specialist locomotives. Clapeyron approached Stevenson, the most famous of the builders of locomotives, but Stevenson found Clapeyron's designs too difficult and declined the contract. Clapeyron then approached Sharp, Roberts, and Company, a firm which made railway locomotives in one of the earliest applications of the use of interchangeable parts. Continuing with his project on his return to France, Clapeyron extended his activities to the design of metal bridges.

In 1844 Clapeyron was appointed professor at the École des Ponts et Chaussées then, in 1848, he was elected to the Paris Academy of Sciences. He served the Academy on many committees, in particular serving on the committee which awarded the mechanics prize. He also served on a committee investigating the construction of the Suez Canal and on a committee which considered how steam engines could be used in the navy.

Clapeyron expressed Sadi Carnot's ideas on heat analytically, with the help of graphical representations, in 1834. Sadi Carnot's work was virtually unknown before Clapeyron's paper in which the Carnot cycle is given in mathematical formulation. This work of Clapeyron had important influences on Thomson and Clausius when its importance for the second law of thermodynamics became apparent. The Clapeyron relation, a differential equation which determines the heat of vaporisation of a liquid, is named after him.