A stator is made up by bonding a first stator part made of a high-permeability material to a second stator part made of a high-permeability material respectively by welding through the intermediary of connections made of a low-permeability material or a nonmagnetic material, interposed therebetween. A value of magnetizing inductance in a transformer is set by adjusting the gap until the value of magnetizing inductance has been set and attaching a segment of the bobbin to a pair of core pieces to maintain the gap. By virtue of the control unit briefly setting the controllable resistor to a very low resistance in the first operating state of the integrated semiconductor memory device, the period of time required for the first and second bit lines require to assume the mid-voltage is shortened. The first object system may be at least one of a managed object system and an unmanaged object system, and the second object system may be at least one of a managed object system and an unmanaged object system. The support hoop increases the ability of the occlusion device to form a seal around the defect and adds additional structural strength to the device by allowing distribution of pressure along a 360\xb0 continuum.