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A new high-power (4500 V) planar metal oxide semiconductor (MOS) device is fabricated and its properties are evaluated. It has low forward voltage drop and a large reverse bias safe operating area (RBSOA), and allows easy MOS control. These properties are superior to those of the conventional insulated gate bipolar transistor (IGBT) and the gate turn-off thyristor (GTO). This is due to the conductivity modulation enhancement effect resulting from an extremely wide gate electrode, which increases the hole storage and the electron injection. At the same time, the junction field effect transistor (JFET) resistance effect does not affect the forward voltage drop. The rate of increase of the off-state voltage (dVD/dt) during the turn-off process affects RBSOA markedly, therefore, it is important to set the gate resistance to an appropriate value. The press pack device that includes 20 chips of this device and 10 fast recovery diode chips can turn off a current of 1200 A at 3600 V DC voltage supply without a snubber circuit.

We succeeded in fusion of paramecia by means of altered electrofusion. Some of the fused cells exhibited life activity and were able to perform several cell divisions. A daughter cell produced by the cell division was a singlet or a doublet and was able to proliferate its clones by repeating mitosis similar to the normal cell. On the other hand, a host fused cell showed distinct discrepancy in its form with elapsed time, according to the subtle difference of the contact between the original cells at the electrofusion.