Abstract: In a plunger for a syringe including a laminated piston which is provided with a shaft with a female thread and which is slidably inserted into a barrel and a rod having a male thread which can be screw-engaged in the threaded hole of the laminated piston, the axial length T of the crest of the female thread and the root of the male thread which engages with the female thread is greater than the axial length t of the root of the female thread and the crest of the male thread.

Abstract: A portable power unit is provided. A desired waveform signal indicative of a desired waveform having a desired frequency is generated. Switching control of a variable control bridge circuit is performed based on the desired waveform signal to cause the variable control bridge circuit to generate an alternating current output. A waveform of the alternating current output is detected to generate an output waveform signal indicative of the detected waveform of the alternating current output. A power factor is detected by comparing the desired waveform signal and the output waveform signal to generate a power factor signal indicative of the detected power factor. Voltage of the alternating current output is controlled based on the power factor signal.

Abstract: An engine speed control apparatus controls the rotational speed of an engine when the engine is overloaded.