The ugly duckling

摘要

More than 90% of the energy we use comes from thermal processes, which produce the bulk of the electricity generated by power plants, as well as powering aeroplanes and most cars. Heat engines have existed since the early eighteenth century, drove the Industrial Revolution and gave rise to the science of thermodynamics. Thermoelectricity was discovered about a century later and is based on the same thermodynamic principles that heat engines depend on, except for the fact that thermoelectric power generators use electrons, rather than steam or air, as the working fluid. A testament to the importance of these fields is the fact that progress in the thermal sciences has been unrelenting: this includes work by Zhao et al. on page 373 of this issue.