人类的生存必需利用能量,而人类所利用的能量最主要的是机械能与热能,至于光能、声能、电能等其它形式的能量多半必需经由机械能转化形成后才能予以利用。事实上即使是机械能,除少量可直接取自自然界(例如,水能、风能等)外绝大多数也必需经由热能予以转化后才可获得。人类的进展历史明显地指明,自从人类掌握了热能转化为机械能的技术工程之后,人类的生活水平和生产水平才能有日新月民的飞速发展 The survival of humankind must use energy, and the most important energy used by mankind is mechanical energy and thermal energy. As for the other forms of energy such as light energy, sonic energy and electric energy, most of the energy must be transformed through mechanical energy before being utilized. In fact, even mechanical energy can be obtained only after a small amount of it can be taken directly from nature (eg, hydroenergy, wind energy, etc.) and must also be converted via thermal energy. The history of human progress has clearly pointed out that since mankind has mastered the technical project of converting thermal energy into mechanical energy, the living standard and production level of mankind can have the rapid development of the New Moon