Abstract: A power conversion apparatus including a three-phase transformer having at least four three-phase windings, and three converter arms each configured by connecting one or plural unit converters each including a switching device and an energy storage element in series. A power source or a load is connected to a first three-phase winding of the transformer, three series circuits which connects second and third three-phase windings of the transformer, and the converter arms in series with each other are connected in parallel, the parallel connection point is a DC terminal, and a magnitude relationship between a coupling coefficient of the first and second three-phase windings, and a coupling coefficient of the first three- and third three-phase windings is equal to a magnitude relationship between a coupling coefficient of the fourth and second three-phase windings, and a coupling coefficient of the fourth and the third three-phase windings.

Abstract: A power conversion apparatus including a three-phase transformer having at least four three-phase windings, and three converter arms each configured by connecting one or plural unit converters each including a switching device and an energy storage element in series. A power source or a load is connected to a first three-phase winding of the transformer, three series circuits which connects second and third three-phase windings of the transformer, and the converter arms in series with each other are connected in parallel, the parallel connection point is a DC terminal, and a magnitude relationship between a coupling coefficient of the first and second three-phase windings, and a coupling coefficient of the first three- and third three-phase windings is equal to a magnitude relationship between a coupling coefficient of the fourth and second three-phase windings, and a coupling coefficient of the fourth and the third three-phase windings.

Abstract: A ferrite core for use in coupling transformers and distributing transformers in CATV equipments such as couplers, distributors and amplifiers, the ferrite core being made of a ferrite having a saturation magnetostriction |?S| of 8×10?6 or less in an absolute value and an initial permeability ?i of 300 or more.

Abstract: A ferrite core for use in coupling transformers and distributing transformers in CATV equipments such as couplers, distributors and amplifiers, the ferrite core being made of a ferrite having a saturation magnetostriction |&lgr;s| of 8×10−6 or less in an absolute value and an initial permeability &mgr;i of 300 or more.

Abstract: The present invention relates to a prophylactic and/or therapeutic composition for ischemic intestinal lesions and/or ileus which comprises as an active ingredient a pyrazolopyridine compound of the following formula: [wherein R1 is lower alkyl group, etc; R2 is a group of the formula: (wherein R4is protected amino group, etc; R5 is hydrogen, etc); etc, and R3 is hydrogen, etc] or a salt thereof.

Abstract: In receiving an optical digital burst signal in an optical communication system, an optical digital burst signal is converted into an electric digital burst signal. A threshold level is determined from the electric digital burst signal. Based on a threshold signal having the determined threshold level whether each of bits of the electric digital burst signal is in a high level or a low level is identified by an identifying circuit. When a sync pattern is detected from the electric digital burst signal, a hunting signal is generated by a synchronization detecting circuit. The duration time of the threshold signal is selected as one of short and long duration times based on whether the hunting signal is significant or insignificant.