Abstract: A spark plug includes: a cylindrical center electrode extending along an axial line; a metal shell that holds the center electrode in an insulated manner; and a ground electrode electrically connected to the metal shell. A spark gap is formed between a side surface of the center electrode and an end face of the ground electrode. The metal shell includes a tubular distal end portion inside which the spark gap is located. In a cross section perpendicular to the axial line and including a center of gravity of the end face, a distance between a center line of the ground electrode, the center line including the center of gravity, and a point of tangency of a tangent line to the side surface of the center electrode is greater than 0 and smaller than a distance between an edge of the end face and the center of gravity.

Abstract: A spark plug includes a center electrode includes a base member, a tip and a melted portion. In a projection view formed by projecting the spark plug perpendicularly to an axial line direction, when an angle that is formed by a discharge surface of the tip and a straight line passing through a first boundary between the tip and the melted portion and a second boundary between the melted portion and the base member, the first boundary and the second boundary being located at two ends of an external shape line of the melted portion, expressed by ?, a distance between the first boundary and the discharge surface in the axial line direction expressed by A, and a distance between the first boundary and the second boundary in a direction perpendicular to the axial line expressed by B, 0<A/B?1 and ??70° are satisfied.

Abstract: A spark plug includes: a center electrode; a metal shell that holds the center electrode in an insulated manner; and a rod-like ground electrode electrically connected to the metal shell and having one end opposed to the center electrode. The metal shell includes a tubular distal end portion inside which the one end of the ground electrode is located. The distal end portion has a hole into which the other end of the ground electrode is inserted. A value obtained by dividing a surface area of a portion of the ground electrode, the portion being located on an inner circumferential side of the distal end portion, by a side surface area of a portion of the ground electrode, the portion being located inside the hole, is less than or equal to 13.1.

Abstract: A gas sensor element includes a solid electrolyte body, a first electrode, a second electrode, and a protective layer. The protective layer includes at least a first catalyst layer that supports a first catalyst metal other than a metal facilitating a reduction reaction of nitrogen oxide and a second catalyst layer that supports only a second catalyst metal facilitating the reduction reaction of the nitrogen oxide. The first catalyst layer and the second catalyst layer are arranged in a path through which a gas under measurement is supplied from the outside of the gas sensor element to the first electrode in such a manner that the first catalyst layer and the second catalyst layer are not in direct contact with each other.

Abstract: This gas sensor element is provided with a solid electrolyte body having oxygen ion conductivity, a measurement electrode that is disposed on the solid electrolyte body and is exposed to a gas to be measured, and a reference electrode that is disposed on the solid electrolyte body and is exposed to a reference gas. The gas sensor element detects a specific gas included in the gas to be measured. The gas sensor element is provided with a contact layer formed so as to cover at least part of the measurement electrode. The contact layer includes rhodium and at least one precious metal other than rhodium. Additionally, the rhodium content in the contact layer relative to the total amount of precious metals included in the contact layer is at least 30 mol % and less than 100 mol %.

Abstract: A spark plug includes a metallic shell member having a tubular portion extending along an axial line of the metallic shell, a center electrode disposed inside the tubular portion and extending along the axial line, and a ground electrode which is inserted into an opening 5 provided in the tubular portion and forms a gap between the center electrode and a forward end portion of the round electrode in a direction in which the round electrode extends. A screw thread is provided on an outer circumferential surface of the tubular portion. The opening has a sloping portion which tapers from the outer circumferential surface of the tubular portion toward an inner circumferential surface side. An angle formed between the 10 sloping portion of the opening and a tangent line to the outer circumferential surface is 90 degrees or greater.

Abstract: A spark plug includes: a center electrode; a metal shell that holds the center electrode in an insulated manner; and a rod-like ground electrode electrically connected to the metal shell and having one end opposed to the center electrode. The metal shell includes a tubular distal end portion inside which the one end of the ground electrode is located. The distal end portion has a hole into which the other end of the ground electrode is inserted. A value obtained by dividing a surface area of a portion of the ground electrode, the portion being located on an inner circumferential side of the distal end portion, by a side surface area of a portion of the ground electrode, the portion being located inside the hole, is less than or equal to 13.1.

Abstract: A spark plug includes: a cylindrical center electrode extending along an axial line; a metal shell that holds the center electrode in an insulated manner; and a ground electrode electrically connected to the metal shell. A spark gap is formed between a side surface of the center electrode and an end face of the ground electrode. The metal shell includes a tubular distal end portion inside which the spark gap is located. In a cross section perpendicular to the axial line and including a center of gravity of the end face, a distance between a center line of the ground electrode, the center line including the center of gravity, and a point of tangency of a tangent line to the side surface of the center electrode is greater than 0 and smaller than a distance between an edge of the end face and the center of gravity.

Abstract: A spark plug which can increase the reactive force of a shelf part. The spark plug includes a cylindrical metal shell (30)-provided around an outer periphery of an insulator. The metal shell includes, on an inner periphery of the metal shell, a proximally oriented surface in contact with the insulator, a distally oriented surface located on the distal side relative to the proximally oriented surface, a first surface extending from the distally oriented surface toward the distal side; and a second surface extending from the proximally oriented surface toward the proximal side. In a section containing an axial line, angle A formed between the distally oriented surface and the first surface and angle B formed between the proximally oriented surface and the second surface have a relationship ?1.15B, with angle A being greater than or equal to 90° and angle B being greater than or equal to 90°.

Abstract: An yttrium oxide-based sintered body contains yttrium oxide as a main constituent and 0.1 wt % or more and 5.0 wt % or less of zirconium on a ZrO2 basis. Such an yttrium oxide-based sintered body made with yttrium oxide and a certain amount of zirconium oxide therein is highly resistant to corrosive chemicals while maintaining superior resistance to plasma and corrosive gases.

Abstract: A gas sensor (1A) including a sensor element (21) extending in an axial-line O direction; a metal shell (11); a tubular holder (30A) located on a front-end side in a gap between an inner surface of the metal shell and an outer surface of the sensor element; a tubular sleeve (43) located on a rear-end side in the gap; a seal member (41) made from inorganic particles and filling a space between the holder and the sleeve in the gap so as to seal the gap between the metal shell and the sensor element; and a pressing portion (16) compressing the seal member in the axial-line direction, and in which a rearward displacement amount (L) of the sleeve due to expansion of the seal member when the pressing portion is removed is greater than 0 mm.

Abstract: A holding device that holds an object on a first surface of a first portion of a plate-shaped member includes a heater pattern formed on a ceramic green sheet and a cover layer covering the heater pattern. A second portion of the plate-shaped member and a heater electrode are manufactured by firing a layered body constituted by a plurality of ceramic green sheets. A second joining portion joins the second portion and a base member. A temperature distribution of a second surface of the second portion is measured while cooling with a cooling mechanism of the base member and supplying power to the heater electrode. Based on a result of the measurement, an electrical resistance of the heater electrode is adjusted by removing a portion of the heater electrode together with the cover layer. A first joining portion joins the second portion and the first portion of the plate-shaped member.

Abstract: A holding device including a ceramic member formed of a sintered ceramic material containing aluminum nitride as a main component, a heating resistor element formed of a metal and disposed in the ceramic member, and an electrically conductive electricity supply member in contact with the heating resistor element. The holding device holds an object on the surface of the ceramic member. In the holding device, at least a portion of the surface of the heating resistor element, excluding its contact surface for contact with the electricity supply member, is covered with a coat layer formed of a nitride containing at least one of Al, Ti, Zr, V, Ta, and Nb. Also disclosed is a method of manufacturing the holding device.

Abstract: The iron loss of a dust core is reduced. A dust core (1) includes soft magnetic metal particles (3) having an average particle size of 5 ?m or more and 30 ?m or less, and a particle boundary phase (6). The particle boundary phase (6) includes a polycrystalline compound containing Al (aluminum). When a sectional structure of the dust core (1) is observed, an area percentage of ?-Al2O3 in the particle boundary phase (6) is 75% or less. An average thickness Ta of the particle boundary phase (6) is 10 nm or more and 300 nm or less. According to the present invention, the iron loss is reduced.

Abstract: A spark plug includes a sealing material disposed around a center electrode in an insulator. On a cross section including a center line of an axial hole, one of long sides of a rectangle is set into the insulator along the center line. The rectangle is divided into 20 equal regions in the insulator by dividing each of short sides of the rectangle into two equal parts and dividing each of the long sides of the rectangle into 10 equal parts. The rectangle has a porosity of 5% or less. Among pores that appear in each of the regions, 10 pores having largest areas are selected as specific pores. The specific pores have an average area of 26.3 ?m2 or less. The specific pores include no more than 30 pores having areas of 37 ?m2 or more and no less than eight pores having areas of 51 ?m2 or more.

Abstract: A spark plug includes a center electrode extending along an axial line and includes a front end portion projecting from an insulator, in a section including the axial line, the front end portion includes a proximal end positioned at a front end of the insulator and an electrode tip end. At least one outline appearing in the section and connecting the proximal end and the electrode tip end of the front end portion to each other includes one or more recessed portions recessed toward the axial line, and a value R/A obtained by dividing a curvature radius R of a rear-end recessed portion, of the one or more recessed portions, closest to the proximal end by a distance A between the rear-end recessed portion and the electrode tip end in the direction of the axial line is more than or equal to 0.12.

Abstract: When a force to bend a spark plug insulator is applied to the spark plug insulator to fracture the spark plug insulator, for a range including a starting point of the fracture out of two ranges into which a fracture surface created by the fracture is divided by a plane which is a plane perpendicular to a direction of the force and includes the axial line, an average of areas of particles appearing in a planar image of the range is 4.4 ?m2 or larger and 8.0 ?m2 or smaller, and a maximum area of the particles is 600 ?m2 or smaller. The particles include large particles having an area of 60 ?m2 or larger and 600 ?m2 or smaller, and, as the large particles, 0.1 particles/mm2 or more are present per unit area of the planar image.

Abstract: A lead-free piezoelectric ceramic composition which includes a primary phase formed of an alkali niobate-based perovskite oxide represented by a compositional formula (A1aM1b)c(Nbd1, Mnd2, M2d3)O3+e (in which element A1 represents at least one species among the alkali metals; element M1 represents at least one species among Ba, Ca, and Sr; element M2 represents at least one species of Ti and Zr; the following conditions: 0<a<1, 0<b<1, a+b=1, 0.80<c<1.10, 0<d1<1, 0<d2<1, 0<d3<1, and d1+d2+d3=1, are satisfied; and e represents a value showing the degree of deficiency or excess of oxygen) and which satisfies the condition: b/(d2+d3)>1.0.

Abstract: An ultrasonic transducer (1) includes a base portion (14), a piezoelectric element (11), a vibration plate (10), and a resonator (12). The resonator (12) is joined to a first surface (21) of the vibration plate (10). A surface, of the piezoelectric element (11), on a side opposite to a side on which the piezoelectric element is joined to the base portion (14), is joined to a second surface (22) of the vibration plate (10). A through-hole (30) is formed in the piezoelectric element (11) so as to penetrate therethrough in a thickness direction of the vibration plate (10). In a planar direction orthogonal to the thickness direction of the vibration plate (10), a joined portion (40) between the vibration plate (10) and the resonator (12) is located inward of a node (20) of vibration of the vibration plate (10), and the through-hole (30) is located inward of the node (20).

Abstract: A lead-free piezoelectric ceramic composition includes a main phase containing an alkali niobate/tantalate perovskite oxide, and a subphase containing a spinel compound containing Ti (titanium). The piezoelectric ceramic composition contains Mn (manganese). A Ti content x is greater than 0 mol % and not greater than 4 mol %, and the Ti content x and an Mn content y satisfy an expression, x2/y?20.0.