There is provided a gas heat exchanger 101 comprising a coolant conduit 102 having a coolant inlet 103 and a coolant outlet 104, a gas cooling conduit 201, and a gas bypass conduit 203. The circuit which operates during the power-down mode is, for example, a self-refresh circuit. The lithography or etch process and the fabrication process interact to cause the predicted characteristics to differ from the design. The female member is provided with a receiving part in which the male member is inserted, and mating holes and formed through the receiving part.