Abstract: Provided are a practical rib type optical waveguide in which polarization dependence and wavelength dependence and the like are small and an optical multiplexer/demultiplexer using the same. An optical waveguide type optical multiplexer/demultiplexer of the present invention includes a substrate, M input optical waveguides and N output optical waveguides including a single mode rib type optical waveguide, multi-mode optical interference regions including a rib type optical waveguide, and reversible tapered regions that smoothly connect the input/output optical waveguides to the multi-mode optical interference regions and include M×N rib type optical waveguides, and both side surfaces of the multi-mode optical interference region are respectively formed in a stepped shape.

Abstract: A spark plug has an insulator, a center electrode disposed in an axial hole, a resistor disposed in the axial hole and a seal member disposed between the resistor and the center electrode in the axial hole. The insulator includes an inner-diameter decreasing portion and a small inner-diameter portion. The center electrode includes a head portion supported on the inner-diameter decreasing portion of the insulator. The spark plug satisfies the following conditions: 1.8 mm?L; and Cp?11 mm where, assuming a region of the insulator from a boundary of the inner-diameter decreasing portion and the small inner-diameter portion to a rear end of the seal member as a specific region, L is a length of the specific region; D1 is an average inner diameter of the axial hole within the specific region; D2 is an average outer diameter of the specific region; and Cp is L/log(D2/D1).

Abstract: In a control device for a limited slip differential that limits a differential operation of front and rear wheels of a four-wheel-drive vehicle having mounted thereon a vehicle behavior control device that controls a braking force, an ECU that controls a torque coupling as the limited slip differential includes: a differential limiting force calculating device that calculates target torque of the torque coupling based on a vehicle traveling state; a differential limiting force correcting device that makes a correction to reduce the target torque based on a command from the vehicle behavior control device; and a thermal load calculating device that calculates a thermal load of the torque coupling. The differential limiting force correcting device limits the correction of the target torque based on the command from the vehicle behavior control device, when the thermal load of the torque coupling is equal to or larger than a predetermined value.

Abstract: A driving force distribution control apparatus includes: a driving force transmission device including a clutch which can change distribution of a driving force to front wheels and rear wheels of a four-wheel drive vehicle; and a controller which controls an engagement force of the clutch in accordance with a traveling state. The controller includes a different-diameter tire detector which detects an attachment of a different-diameter tire to one of the front wheels and the rear wheels when a rotation speed ratio between the front wheels and the rear wheels continues to be equal to or larger than a reference rotation speed ratio for a predetermined time. The different-diameter tire detector performs detection of the attachment of the different-diameter tire when it is determined that the wheels are unlikely to slip based on an outside condition.

Abstract: A method for manufacturing a spark plug includes an assembling step of assembling an insulator into a metallic shell by insertion of the insulator into the metallic shell from an axially rear end opening portion of the metallic shell. The assembling step includes a displacement restricting step of restricting a relative positional displacement between the metallic shell and the insulator in a radial direction intersecting with the axial direction so as to reduce eccentricity between the axis of the metallic shell and the axis of the insulator to a predetermined value or less, while allowing a relative positional displacement between the metallic shell and the insulator in the axial direction. In the assembling step, whether or not the insulator is cracked in the assembling step is judged by detecting acoustic emission from the insulator.

Abstract: Provided is a method for manufacturing a spark plug, wherein at least one of a center electrode and the ground electrode includes an electrode base material and a columnar noble metal tip welded to the electrode base material. The method includes a laser welding step of applying a pulse oscillation laser to form a plurality of unit fusion portions on a peripheral area of a boundary between the electrode base material and the noble metal tip and welding the electrode base material and the noble metal tip. One unit fusion portion is formed by one-time laser irradiation. In the laser welding step, an irradiation axis of the laser is displaced from a central axis of the noble metal tip in a radial direction of the noble metal tip. When a diameter of the noble metal tip is denoted as a diameter A and an amount of displacement of the irradiation axis of the laser is denoted as X, A/20?|X|?A/4 is satisfied.

Abstract: In a spark plug, at least one of a center electrode and a ground electrode has a cover portion and a core portion having a different thermal expansion coefficient. The core portion has a concave portion and a convex portion formed at a front end thereof. The convex portion is such that, in a cross section passing through a barycenter of a front surface of the electrode and also passing through the convex portion, an area of the convex portion delimited by a line perpendicular to a bisector of the convex portion and passing through a point 0.2 mm shifted from a front end of the convex portion in the direction of the bisector is smaller than an area of a triangle formed by connecting the front end of the convex portion and intersections of the line perpendicular to the bisector and a contour of the convex portion.

Abstract: An optical signal control device includes an optical signal control unit and a drive circuit. The optical signal control unit includes m number of optical waveguides for propagating carrier light and (m×n) number of interaction regions, n number of interaction regions formed on each of the optical waveguides. The drive circuit includes (m×n) number of phase control units. The (m×n) number of phase control unit output a data signal for controlling the action of the (m×n) number of interaction regions to each of the (m×n) number of interaction regions. Each of the (m×n) number of phase control units outputs the data signal so that timing when the carrier light propagates to the interaction region to output the data signal and timing when the data signal arrives at the interaction region are synchronized. One of m and n is two or more.

Abstract: A spark plug wherein an outer diameter of a first face that is a gap foliating face of the center electrode tip is denoted as R1, an outer diameter of a second face that is a gap forming face of the ground electrode tip is denoted as R2, a length of the gap is denoted as G1, and an average distance of a distance between an end in the first direction of the first face and an end in the first direction of the second face and a distance between an end in the second direction of the first face and an end in the second direction of the second face is denoted as G2, R1<R2, 0.5 mm?R1?1.1 mm, 0.7 mm?R2?1.2 mm, 0.6 mm?G1?1.3 mm, and 1.4?(R2/R1)×(G2/G1)?1.8 are satisfied.

Abstract: A spark plug includes a center electrode, an insulator, a metallic shell, and a seal member for providing a seal between the insulator and the metallic shell. The insulator includes a first portion, a second portion located axially forward of the first portion and being smaller than the first portion, and an insulator first-diameter-reducing-portion whose outside diameter reduces forward and which connects the first portion and the second portion. The metallic shell includes a protrusion that includes a metallic shell diameter-reducing-portion whose inside diameter reduces forward. The seal member is disposed between the insulator first-diameter-reducing-portion and the metallic shell diameter-reducing-portion.

Abstract: A spark plug includes a ceramic insulator having an engagement portion, and a metallic shell provided around the ceramic insulator and having a protrusion. The protrusion has a diameter-decreasing portion, which seats on the engagement portion via an annular seat packing. On a cross section including an axial line, ?s>?p is satisfied, where ?p represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the engagement portion, and ?s represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the diameter-decreasing portion. In the aforementioned cross section, Hvo>Hvi is satisfied, where Hvo represents the Vickers hardness (Hv) of the seat packing at the midpoint of a first line segment, and Hvi represents the Vickers hardness (Hv) of the seat packing at the midpoint of a second line segment.

Abstract: In a control device for a limited slip differential that limits a differential operation of front and rear wheels of a four-wheel-drive vehicle having mounted thereon a vehicle behavior control device that controls a braking force, an ECU that controls a torque coupling as the limited slip differential includes: a differential limiting force calculating device that calculates target torque of the torque coupling based on a vehicle traveling state; a differential limiting force correcting device that makes a correction to reduce the target torque based on a command from the vehicle behavior control device; and a thermal load calculating device that calculates a thermal load of the torque coupling. The differential limiting force correcting device limits the correction of the target torque based on the command from the vehicle behavior control device, when the thermal load of the torque coupling is equal to or larger than a predetermined value.

Abstract: A spark plug includes an insulator; a center electrode; a metallic shell; a ground electrode disposed at a forward end portion of the metallic shell and forming a gap in cooperation with a forward end portion of the center electrode; and a tip at least a portion of which is joined to at least the one of two side surfaces of the ground electrode which is disposed downstream with respect to fuel gas flow. In a first imaginary plane which contains a forward end surface of the center electrode and on which a discharge surface of the tip is projected, at least a portion of a projected image of the discharge surface is located within a range of 2.5G from the outer circumference of the forward end surface of the center electrode, where G (mm) is the size of the gap.

Abstract: A spark plug includes an insulator including an axial hole and having an outer periphery with a tapered outer face; a metal shell having a thread portion and a tapered inner face; and a circular packing sandwiched between the tapered outer face of the insulator and the tapered inner face of the metal shell. On at least one cross section including the axis, (A/B)?3.1, B?0.25, and (A+B)?2.0 are satisfied, where A represents a length of (a difference between an effective diameter of the thread portion and an inner diameter at a rear end of the tapered inner face)/2, and B represents a length of (a difference between the inner diameter at the rear end of the tapered inner face and an inner diameter at a front end of the tapered inner face)/2.

Abstract: Waveguide-type optical phase modulator regions of a linear accelerator-type column electrode structure MZ optical modulator are arranged on a semiconductor optical waveguide. A transmission line of an integrated circuit receives a clock signal through a buffer circuit disposed on an input side. Clock terminators are connected between an end of the transmission line and clock terminator power supply electrodes (VCa, VCb). Individual driving circuits receive the clock signal from different positions of the transmission line. An i (1?i?m, i is an integer)-th individual driving circuit counted from the input side outputs a signal obtained by amplifying a digital input signal in synchronization with the clock signal to an i-th waveguide-type optical phase modulator region.

Abstract: A spark plug includes a ceramic insulator having an engagement portion, and a metallic shell provided around the ceramic insulator and having a protrusion. The protrusion has a diameter-decreasing portion, which seats on the engagement portion via an annular seat packing. On a cross section including an axial line, ?s>?p is satisfied, where ?p represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the engagement portion, and ?s represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the diameter-decreasing portion. In the aforementioned cross section, Hvo>Hvi is satisfied, where Hvo represents the Vickers hardness (Hv) of the seat packing at the midpoint of a first line segment, and Hvi represents the Vickers hardness (Hv) of the seat packing at the midpoint of a second line segment.

Abstract: A spark plug includes an insulator; a center electrode; a metallic shell; a ground electrode disposed at a forward end portion of the metallic shell and forming a gap in cooperation with a forward end portion of the center electrode; and a tip at least a portion of which is joined to at least the one of two side surfaces of the ground electrode which is disposed downstream with respect to fuel gas flow. In a first imaginary plane which contains a forward end surface of the center electrode and on which a discharge surface of the tip is projected, at least a portion of a projected image of the discharge surface is located within a range of 2.5G from the outer circumference of the forward end surface of the center electrode, where G (mm) is the size of the gap.

Abstract: An optical modulator module includes an optical modulator including an optical waveguide which conducts an inputted optical signal, and m modulator regions on the optical waveguide; and m discrete driving circuits serially connected to one another. The discrete driving circuits include a driving circuit which outputs a signal obtained from a digital input signal with a synchronization signal to one of the modulator regions, and a phase shifting circuit which outputs a signal resulting from giving a delay to a signal branched from the synchronization signal. A discrete driving circuit receives the signal outputted from the phase shifting circuit. Each of the modulator regions includes modulation electrodes, an electric field caused by a modulation electric signal applied to each of the modulation electrodes penetrates by a penetration length d, and every two adjacent modulation electrodes has a distance Lgap given by Lgap=2d.

Abstract: A driving force distribution control apparatus includes: a driving force transmission device including a clutch which can change distribution of a driving force to front wheels and rear wheels of a four-wheel drive vehicle; and a controller which controls an engagement force of the clutch in accordance with a traveling state. The controller includes a different-diameter tire detector which detects an attachment of a different-diameter tire to one of the front wheels and the rear wheels when a rotation speed ratio between the front wheels and the rear wheels continues to be equal to or larger than a reference rotation speed ratio for a predetermined time. The different-diameter tire detector performs detection of the attachment of the different-diameter tire when it is determined that the wheels are unlikely to slip based on an outside condition.

Abstract: A spark plug wherein an outer diameter of a first face that is a gap foliating face of the center electrode tip is denoted as R1, an outer diameter of a second face that is a gap forming face of the ground electrode tip is denoted as R2, a length of the gap is denoted as G1, and an average distance of a distance between an end in the first direction of the first face and an end in the first direction of the second face and a distance between an end in the second direction of the first face and an end in the second direction of the second face is denoted as G2, R1<R2, 0.5 mm?R1?1.1 mm, 0.7 mm?R2?1.2 mm, 0.6 mm?G1?1.3 mm, and 1.4?(R2/R1)×(G2/G1)?1.8 are satisfied.