Shape memory alloys (SMA) are in general usage today. What exactly is a SMA? As the name suggests, this alloy can remember its original shape or form. Essentially it is a metal which can be deformed when cold and will return to its first shape when hot. The particular alloy we are speaking about is nickel titanium. We can see here one application in a conventional piston. When the piston is cold, the SMA coil or spring contracts and so the piston does not move. Heat causes it to expand and consequently the piston moves up. The advantage is that the device can work without any mechanical power, just from the heat which is supplied by the engine itself. В. Найдите в приведенном выше тексте 5 пар синонимов и 3 пары антонимов.