Abstract: A peripheral wall extending portion is formed in such a manner that a front end side of a cylindrical hole of a metal shell projects forward in an axis O direction, and the peripheral wall extending portion comprising: a projecting portion formed into a projecting shape, and a connecting portion which connects between the projecting portions. A fuel injected from an injection orifice of an injector strikes against the projecting portion and is unlikely to directly reach to a spark discharge gap formed between a noble metal tip and a front end portion of a ground electrode. The fuel that strikes against the projecting portions without striking against the projecting portion is separated into a droplet-like incompletely vaporized fuel that adheres to the projecting portions and a vaporized fuel being reflected to a perimeter of the spark discharge gap.

Abstract: For producing a spark plug that has a high dimensional accuracy in the spark gap, a method is disclosed which comprises (a) preparing a semi-finished spark plug unit (100b) which comprises a center electrode (20) that has a leading end portion (22), a metal shell (50) that holds therein through an insulator (10) the center electrode (20) except the leading end portion (22) and a ground electrode (30) fixed to a leading end of the metal shell (50), (b) bending the ground electrode (30) so that a bent front portion (31) of the ground electrode (30) projects toward the leading end portion (22) of the center electrode (20), (c) putting an electrode tip (95) on a given part of the bent front portion (31) of the ground electrode (30) in such a manner that a front portion of the electrode tip (95) projects from the bent front portion (31) toward the leading end portion (22) of the center electrode (20) and (d) welding the electrode tip (95) to the given part of the bent front portion (31) of the ground electrode (30

Abstract: Projecting portions extended in an axis (O) direction and projecting forward are formed on a front end face of a cylindrical portion provided on a front end side of a metal shell. The projecting portions are disposed at an equal interval therebetween in a circumferential direction revolving around a center S of a firing portion. Regardless of the mounting state of a spark plug on an engine head (i.e., a shift in the circumferential direction caused by a difference in tightening of a fitting screw), a side face or an end face of any one of projecting portions will face an upstream side of a fuel (combustible air-fuel mixture layer) flow direction, which flows with an air current in a combustion chamber. Therefore, the combustible air-fuel mixture layer colliding with the projecting portion includes the flow direction directed to the firing portion as its reflective direction and is thus adrift around the firing portion.

Abstract: An optical disk drive includes a pickup head, a servo circuit, and a controller. An optical disk has a first area and a second area for which different tracking methods are to be used. The controller may cause the pickup head to make a seek for a target address in the first area from a position in this area that is farther from the boundary between the two areas than the address. If the controller cannot perform tracking servo control after the seek is made, and if the calculated address is located in a critical region, the controller immediately causes the pickup head to make a seek by a specified number of addresses toward the position farther from the boundary. After the seek is made, the controller performs tracking servo control again.

Abstract: A spark plug includes a ground electrode formed with a flat region and a convex curved region on an outer peripheral surface thereof. The flat region is located on a front end of the ground electrode and has a length of 0.2 mm or more from a front end face of the ground electrode in a longitudinal direction of the ground electrode. The ground electrode satisfies the following dimensional condition (1) with respect to first and second cross sections of the ground electrode taken through the convex curved region and the flat region in directions perpendicular to the longitudinal direction of the ground electrode, 0.950?(S2/L2)/(S1/L1)?0.995 ??(1) where S1 is the area of the first cross section; L1 is the perimeter of the first cross section; S2 is the area of the second cross section; and L2 is the perimeter of the second cross section.

Abstract: A spark plug includes an outer electrode including an outer electrode tip of which a distal end surface is spaced from an outer peripheral surface of a leading end portion of a center electrode to define a spark discharge gap. A protruding insulator portion of a cylindrical insulator protrudes at least 1.0 mm from a leading end surface of a cylindrical metal shell. A protruding center electrode portion of the center electrode protrudes at least 3.5 mm from the leading end surface of the cylindrical metal shell. A relationship (?1+?2)/2?75 degrees is satisfied where the angle ?1 is defined as a central angle (degrees) of a first circular sector having a point B1 as a center thereof, and the angle ?2 is an average value (degrees) of the central angles of two second circular sectors having the point B1 as a center thereof.

Abstract: A spark plug including: a center electrode; a substantially cylindrical insulator; a cylindrical metal shell; a ground electrode having a base end joined to a leading end portion of the metal shell and a distal end bent toward the axis line. The ground electrode includes: a thick portion provided on a base end side, a thin portion provided on a distal end side, and a stepped portion provided on an inner peripheral surface between the thick portion and the thin portion. A noble metal tip is joined to and partially embedded in the inner peripheral surface of the thin portion and disposed to form a gap between the noble metal tip and the leading end portion of the center electrode.

Abstract: A spark plug including: a ground electrode including a thick portion provided on a base end side, a thin portion provided on a distal end side, and a stepped portion provided on an inner peripheral surface between the thick portion and the thin portion; a noble metal tip partially embedded in an inner peripheral surface of the thin portion; and a bulge portion provided on the inner peripheral surface of the thin portion between the stepped portion and the noble metal tip. When viewed from a side surface of the ground electrode, a relationship [a protruding height of the noble metal tip from the inner peripheral surface of the thin portion]?[a protruding height of the bulge portion from the inner peripheral surface of the thin portion].

Abstract: The present invention provides a niobium 2-ethylhexanoate derivative having a niobium content of from 13 to 16 mass % and a carbon content within a range of from 50 to 58 mass %, the niobium 2-ethylhexanoate derivative consisting only of: niobium atoms, oxygen atoms, and 2-ethylhexanoic acid residues; the niobium 2-ethylhexanoate derivative can be produced by reacting pentakis(alkoxy)niobium with 2-ethylhexanoic acid; further, the organic acid metal salt composition of the present invention includes the niobium 2-ethylhexanoate derivative, a metal precursor other than niobium, and at least one kind of an organic solvent; and the thin film including a niobium element and metal other than niobium can be formed on a substrate by applying the organic acid metal salt composition on the substrate and heating the substrate with the applied organic acid metal salt composition.

Abstract: A spark plug including: a rod-shaped center electrode; an insulator; a metal shell; a ground electrode joined to the metal shell and bent toward the center electrode; a noble metal tip joined to an end portion of the ground electrode and opposing a leading end portion of the center electrode via a gap; and a bulge portion. A part of the noble metal tip is embedded in the ground electrode, and another part of the noble metal tip protrudes from a distal end surface of the ground electrode. A relationship A?0.25 mm is satisfied where A (mm) is a protruding length of the noble metal tip from the distal end surface. The bulge portion covers a center part of a boundary between the noble metal tip and the end surface in a width direction.

Abstract: An optical disk device includes a test recording portion, a power control portion, a recording portion and a power correction portion. The power control portion determines a first recording power to record recording information to the optical disk based on test information recorded by the test recording portion. The power correction portion calculates a first average of modulation of the recording information recorded on a first track of the optical disk at the first recording power and a second average of modulation of the recording information recorded on a second track of the optical disk at the first recording power. The power correction portion increases the first recording power to a second recording power when the second average of the modulation drops below a first threshold value that is preset and drops below a second threshold value that is calculated based on the first average of modulation.

Abstract: An optical disc apparatus varies a tilt angle of an optical pickup from inward to outward of an optical disc, and stores a then obtained TE (Tracking Error) signal in a memory of a control circuit. The control circuit extracts amplitude values of the TE signal at tilt angles at predetermined angular intervals from the TE signal stored in the memory, and temporarily stores the extracted amplitude values in the memory, and further uses the stored amplitude values to determine a cubic curve to approximate the extracted amplitude values based on the least squares method. After determining the cubic curve, the control circuit sets a tilt angle corresponding to a maximum point of the cubic curve as an optimum tilt angle. This makes it possible to obtain a proper optimum tilt angle even with a surface-vibrating optical disc which much vibrates in the thickness direction during rotation.

Abstract: To provide a spark plug with improved heat resistance and an internal combustion engine in which that spark plug is mounted where there is good conduction of the heat near the opening on the combustion chamber side of the mounting hole for the spark plug provided in the engine and the effects of thermal stress occurring near that opening are mitigated. A cylindrical part without threads formed thereon is provided on the leading end side of a metal housing of a spark plug and the thermal stress applied to a mounting hole is mitigated by avoiding close contact with the mounting hole of an engine head. Furthermore, the spark plug has a mounting structure in which the leading end surface of the cylindrical part is disposed 1.55 mm or more to the base end side in a mounting hole in the direction of the axial line O with respect to the wall surface inside the combustion chamber.

Abstract: A spark plug for an internal combustion engine, includes: a cylindrical insulating body; a center electrode; a cylindrical metal shell; and a ground electrode, as defined herein, wherein the noble metal tip is bonded to the ground electrode via a molten bond, and when viewed in a cross-section including a center axis of the noble metal tip along a longitudinal direction of the ground electrode, a sum of a cross-sectional area of a base-end-side molten bond (A) positioned at a base end side of the ground electrode and a cross-sectional area of a front-end-side molten bond (B) positioned at a front end side of the ground electrode is equal to or greater than 4 mm2, and the cross-sectional area of the front-end-side molten bond (B) is 1.1 to 1.3 times greater than that of the base-end-side molten bond (A).

Abstract: A spark plug including a ground electrode which has an excellent heat sinking ability. The ground electrode includes a core material therein. Heat received from a combustion chamber during a drive of an internal-combustion engine can be conducted to the core material. More effective heat sinking ability can be achieved because of the core material.

Abstract: A spark plug including a center electrode; an insulator; and a metal shell, wherein the metal shell includes: a mounting portion; a cylindrical portion; a seal portion; a crimping portion; and a buckled portion all as defined herein, and a relationship A<B is satisfied, in which A is a length in the axial direction of an external thread formed on the mounting portion, and B is a length of the cylindrical portion in the axial direction.

Abstract: An optical disk drive includes a pickup head, a recording/reproducing circuit, a servo circuit, a driver, a thread motor, a spindle motor, and a controller. An optical disk has a first area and a second area for which different tracking methods are to be used. The controller may causes the pickup head to make a seek for a target address in the first area from a position in this area that is farther from the boundary between the two areas than the address. The controller calculates the target address by detecting the number of times the reflection intensity of the optical disk changes during the seek, for example. If the controller can perform no tracking servo control after the seek is made, and if the calculated address is located in a critical region, the controller immediately causes the pickup head to make a seek by a specified number of addresses toward the position farther from the boundary. After this seek is made, the controller performs tracking servo control again.

Abstract: In an optical disk recorder (1), when a user instruct to format an optical disc (2), a main control unit 3 reads out file management data from a file management data area of the optical disc (2), and writes the read file management data at a specific area of the optical disc (2) through an optical head (6) so as to save the read file management data. When the user instruct to cancel the formatting of the optical disc (2), the main control unit (3) reads out the saved file management data from the optical disc (2) and rewrite the saved file management data into the original file management data area again. Thereby, the user can use the user data recorded before the formatting of the optical disc (2).

Abstract: An optical disc apparatus varies a tilt angle of an optical pickup from inward to outward of an optical disc, and stores a then obtained TE (Tracking Error) signal in a memory of a control circuit. The control circuit extracts amplitude values of the TE signal at tilt angles at predetermined angular intervals from the TE signal stored in the memory, and temporarily stores the extracted amplitude values in the memory, and further uses the stored amplitude values to determine a cubic curve to approximate the extracted amplitude values based on the least squares method. After determining the cubic curve, the control circuit sets a tilt angle corresponding to a maximum point of the cubic curve as an optimum tilt angle. This makes it possible to obtain a proper optimum tilt angle even with a surface-vibrating optical disc which much vibrates in the thickness direction during rotation.

Abstract: A spark plug includes a metallic shell having a stepped portion an insulator disposed inside the metallic shell, while being engaged with the stepped portion of the metallic shell, and having an axially extending through hole; a center electrode fixed within the through hole of the insulator; and a ground electrode having a tip end portion bent toward the center electrode to thereby form a spark discharge gap. The insulator is formed such that the outer diameter of the insulator decreases toward the tip end side from an engagement position at which the insulator engages the stepped portion and such that the diameter decreases stepwise at an axial position between the engagement position and the tip end of the insulator. The diameter reduction ratio Y1=D1/d1 is 0.