Semiconductors are those materials that are neither good conductors nor the good insulators of heat and electricity. Silicon (Si), Germanium (Ge) and Cadmium Sulphide (CdS) are semiconductors which work as conductors in some special conditions only.
Improve the bracketed part of the sentence. In the eighteenth century, Japan's feudal overlords, from the shogun to the humblest samurai, found themselves (on) financial stress.