Abstract: A direct-current circuit breaker includes a first main circuit breaker inserted into a first direct-current line, a resonance circuit connected in parallel to the first main circuit breaker, a MOSA connected in parallel to the first main circuit breaker via the resonance circuit, a second main circuit breaker inserted into a second direct-current line, a switch connected in series to the second main circuit breaker, a resonance circuit connected in parallel to the second main circuit breaker, and a MOSA connected in parallel to the second main circuit breaker via the resonance circuit. The second direct-current line is a line that branches off from the first direct-current line and returns to the first direct-current line. The switch is inserted upstream of the second direct-current line.

Abstract: A direct-current breaking device includes a main circuit breaker inserted on a DC line, a resonant circuit connected in parallel with the main circuit breaker, and a MOSA connected in parallel with the main circuit breaker via the resonant circuit. The resonant circuit includes first, second, third, and fourth switching elements, a capacitor, and a reactor. A first circuit unit including the first switching element and the second switching element connected in series with each other, and a second circuit unit including the third switching element and the fourth switching element connected in series with each other are connected in parallel. The capacitor is connected between a connection point of the first switching element and the second switching element and a connection point of the third switching element and the fourth switching element to constitute a bridge circuit. The bridge circuit and the reactor are in series with each other.

Abstract: A resin composition including: a thermosetting resin component including a mesogen; and a phosphorus atom-containing thermoplastic polymer type frame retardant, wherein the thermoplastic polymer type frame retardant is a phosphorous atom-containing formed by polymerizing or copolymerizing one of monomers represented by general formulae (1) and (2) below, wherein, in the general formulae (1) and (2), each of R1 and R2 is any one of an alkyl group, an alkoxy group, an aryl group and an aryloxy group, R1 and R2 being different or identical, and R3 is a methyl group or a hydrogen atom.

Abstract: A DC circuit breaker includes a fuse unit to interrupt a large current with a fuse, and the fuse unit includes a high-speed disconnector that is connected in parallel to the fuse and is opened when a fault current is detected.

Abstract: A compound comprises a resin composition containing an epoxy resin, a phenol resin, a wax, and an imidazole compound, and a metal element-containing powder, wherein the epoxy resin comprises a crystalline epoxy resin, the wax comprises a montanic acid ester, and the content of the metal element-containing powder is 90 mass % or more based on the total mass of the compound.

Abstract: In order to provide a DC interrupting device that does not easily cause erroneous melting of current-limiting fuses at normal times with no fault current, and that can also deliver good current-limiting performance at the time of occurrence of fault current, the DC interrupting device includes: a (k?1)th current path including a (k?1)th current-limiting fuse, where k is an integer of not less than two and not more than N, and N is an integer of not less than two; and a kth current path connected in parallel to the (k?1)th current path and including a kth current-limiting fuse. The inductance value of the inductance component of the kth current path is higher than the inductance value of the inductance component of the (k?1)th current path.

Abstract: Provided is a powder magnetic core for a reactor, whose electromagnetic properties are difficult to change with time, even when applied to a reactor used in a state that the core is exposed without being potted. The powder magnetic core for a reactor consists essentially of a compact composed of an insulation-coated iron-based soft magnetic powder that an insulating film is formed on the surface of an iron-based soft magnetic powder, and which has such a change with time of 500 hours at 180° C. that a ratio of decrease in effective magnetic permeability being 1% or less. In the compact, the content of gapping between two adjacent particles of the insulation-coated iron-based soft magnetic powder is 2 vol % or less.

Abstract: The powder magnetic core of the present invention can exhibit reliable superposition property in which variance rate of inductance value is small even if superposed current is varied, and can reduce the number of cores used in a reactor. The powder magnetic core comprises: soft magnetic powder particles, and gaps between the soft magnetic powder particles, in which the powder magnetic core has a density ratio of 90 to 95%, and when observing a cross section thereof, layered gaps having thicknesses of 1 to 3 ?m and widths of 20 to 200 ?m are formed inside of the powder magnetic core. It is desirable that the layered gaps be not less than 50% of all the gaps in a cross sectional area ratio.

Abstract: A piezoelectric device has: a ceramic substrate having a first principal surface and a second principal surface opposed to each other; a piezoelectric element arranged on the first principal surface; a frame having a first face and a second face opposed to each other and arranged on the ceramic substrate so as to surround the piezoelectric element; a metal layer arranged on the second face of the frame; and a metal lid arranged on the metal layer so as to close a space surrounded by the frame. The first face of the frame is in contact with the first principal surface of the ceramic substrate. The metal layer and the metal lid are joined to each other by resistance welding. The frame has a composite portion containing a metal and a metal oxide and the composite portion includes the second face and is in contact with the metal layer.

Abstract: The compact for a magnetic core is manufactured by filling a soft magnetic powder in the die hole, pressing it to form a compact at a density ratio of the soft magnetic powder being 91% or more, and extruding it from the die hole. Before filling the soft magnetic powder to the die hole, a lubricating coating containing lubricating oil and molybdenum disulfide particles is formed on the inner surface of the die hole. It is more effective when further containing insulating ceramic particles. On the extrusion-sliding surface, the compact has a surface layer of the structure that molybdenum disulfide particles and the insulating ceramic particles are interposed between the soft magnetic powder particles, and insulation of soft magnetic powder particles in the surface layer is not destroyed by extrusion. This provides a powder magnetic core suitable for high frequency application.

Abstract: Provided is a piezoelectric device capable of improving measurement precision of a temperature of a piezoelectric element. A piezoelectric device (1) includes a package (2) including a housing member (4) having a thermistor substrate (3) and a frame (7) provided to project from a first main surface (3a) of the thermistor substrate (3) and in which a housing part (6) is formed by the first main surface (3a) and the frame (7) and a lid (9) provided on the frame (7) to cover a space (5) of the housing part (6), and a piezoelectric vibration element (5) provided on the first main surface (3a) of the thermistor substrate (3) in the housing part (6), wherein the thermistor substrate (3) is a multilayer negative temperature coefficient (NTC) thermistor.

Abstract: The present invention provides a powder magnetic core which has a low iron loss and an excellent constancy of magnetic permeability and is suitably used as a core for a reactor mounted on a vehicle. The powder magnetic core is a compact of a mixed powder containing an iron-based soft magnetic powder having an electrical insulating coating formed on its surface and a powder of a low magnetic permeability material having a heat-resistant temperature of 700° C. or higher than 700° C. and a relative magnetic permeability of not more than 1.0000004. The density of the compact is 6.7 Mg/m3 or more, and the low magnetic permeability material exists in the gap among the soft magnetic powder particles in the green compact.

Abstract: The powder magnetic core of the present invention can exhibit reliable superposition property in which variance rate of inductance value is small even if superposed current is varied, and can reduce the number of cores used in a reactor. The powder magnetic core comprises: soft magnetic powder particles, and gaps between the soft magnetic powder particles, in which the powder magnetic core has a density ratio of 90 to 95%, and when observing a cross section thereof, layered gaps having thicknesses of 1 to 3 ?m and widths of 20 to 200 ?m are formed inside of the powder magnetic core. It is desirable that the layered gaps be not less than 50% of all the gaps in a cross sectional area ratio.

Abstract: The compact for a magnetic core is manufactured by filling a soft magnetic powder in the die hole, pressing it to form a compact at a density ratio of the soft magnetic powder being 91% or more, and extruding it from the die hole. Before filling the soft magnetic powder to the die hole, a lubricating coating containing lubricating oil and molybdenum disulfide particles is formed on the inner surface of the die hole. It is more effective when further containing insulating ceramic particles. On the extrusion-sliding surface, the compact has a surface layer of the structure that molybdenum disulfide particles and the insulating ceramic particles are interposed between the soft magnetic powder particles, and insulation of soft magnetic powder particles in the surface layer is not destroyed by extrusion. This provides a powder magnetic core suitable for high frequency application.

Abstract: Provided is a powder magnetic core for a reactor, whose electromagnetic properties are difficult to change with time, even when applied to a reactor used in a state that the core is exposed without being potted. The powder magnetic core for a reactor consists essentially of a compact composed of an insulation-coated iron-based soft magnetic powder that an insulating film is formed on the surface of an iron-based soft magnetic powder, and which has such a change with time of 500 hours at 180° C. that a ratio of decrease in effective magnetic permeability being 1% or less. In the compact, the content of gapping between two adjacent particles of the insulation-coated iron-based soft magnetic powder is 2 vol % or less.

Abstract: Provided is a piezoelectric device capable of improving measurement precision of a temperature of a piezoelectric element. A piezoelectric device (1) includes a package (2) including a housing member (4) having a thermistor substrate (3) and a frame (7) provided to project from a first main surface (3a) of the thermistor substrate (3) and in which a housing part (6) is formed by the first main surface (3a) and the frame (7) and a lid (9) provided on the frame (7) to cover a space (5) of the housing part (6), and a piezoelectric vibration element (5) provided on the first main surface (3a) of the thermistor substrate (3) in the housing part (6), wherein the thermistor substrate (3) is a multilayer negative temperature coefficient (NTC) thermistor.

Abstract: A piezoelectric device has: a ceramic substrate having a first principal surface and a second principal surface opposed to each other; a piezoelectric element arranged on the first principal surface; a frame having a first face and a second face opposed to each other and arranged on the ceramic substrate so as to surround the piezoelectric element; a metal layer arranged on the second face of the frame; and a metal lid arranged on the metal layer so as to close a space surrounded by the frame. The first face of the frame is in contact with the first principal surface of the ceramic substrate. The metal layer and the metal lid are joined to each other by resistance welding. The frame has a composite portion containing a metal and a metal oxide and the composite portion includes the second face and is in contact with the metal layer.

Abstract: An insertion-hole blockage-rate evaluation system is applied to a heat exchanger that includes a heat transfer tube and a tube support plate having an insertion hole formed therein for inserting the heat transfer tube therethrough. The tube support plate is displayed in a three dimensional manner in an elliptical diagram with a ratio between a long axis and a short axis being in a range from 1.0 to 2.0 inclusive, each of the tube support plates is serially arranged so as not to overlap on each other, and the insertion-hole blockage-rate evaluation system includes an imaging process of color-coding and displaying the diagram displayed in the three-dimensional elliptical shape according to a value of a blockage rate of the insertion hole acquired by checking the blockage rate of the insertion hole.

Abstract: An insertion-hole blockage-rate evaluation system is applied to a heat exchanger that includes a heat transfer tube and a tube support plate having an insertion hole formed therein for inserting the heat transfer tube therethrough. The tube support plate is displayed in a three dimensional manner in an elliptical diagram with a ratio between a long axis and a short axis being in a range from 1.0 to 2.0 inclusive, each of the tube support plates is serially arranged so as not to overlap on each other, and the insertion-hole blockage-rate evaluation system includes an imaging process of color-coding and displaying the diagram displayed in the three-dimensional elliptical shape according to a value of a blockage rate of the insertion hole acquired by checking the blockage rate of the insertion hole.

Abstract: A powder magnetic core of the present invention is a powder magnetic core that includes an insulating layer containing a particulate metal oxide between metal powders, in which the insulating layer contains Ca, P, O, Si, and C as elements. According to the present invention, it is possible to provide a powder magnetic core in which securing of a constant permeability characteristic under a high magnetic field and decrease in core loss are compatible with each other, and a method for producing the powder magnetic core.