Abstract: A spark plug comprised of a spark plug main body and a cylindrical pressing member used for mounting the spark plug main body on an internal-combustion engine. The spark plug main body includes a cylindrical metal shell. A removing-tool engagement portion is formed on an outer circumferential face of the metal shell at a front end side of a caulking portion. The removing-tool engagement portion is used for engaging with a tool, when removing the spark plug main body from a plug hole of an internal-combustion engine.

Abstract: There is provided manufacturing method of a spark plug that includes a center electrode and a ground electrode with a discharge gap left therebetween. At least one of the center electrode and the ground electrode has an electrode body containing a base metal and a noble metal tip welded to the electrode body. The spark plug manufacturing method includes a laser welding step for welding the noble metal tip and the electrode body by placing the noble metal tip at a given position on the electrode body, irradiating a pulsed laser onto the noble metal tip and the electrode body and thereby sequentially forming welding spots corresponding to pulses of the laser in a circumferential direction of the noble metal tip, wherein at least one of the laser pulses is an initially increasing type laser pulse having a laser intensity waveform in which a laser intensity increases with time during a predetermined initial period from a pulse start time.

Abstract: A method for producing activated carbon for electrodes of electric double layer capacitors is disclosed which comprises an activation step wherein activated carbon is obtained by mixing an alkali metal hydroxide with a carbon raw material for the activated carbon and heating the mixture in an inert gas atmosphere, a deactivation removal step wherein the alkali metal in the activated carbon is deactivated and removed, and a heat treatment step wherein the activated carbon having gone through the deactivation removal step is heated in an inert gas atmosphere at a temperature higher than 400° C. but not higher than the heating temperature in the activation step.

Abstract: A spark plug including: a center electrode including an electrode base member and a core member; an electrode tip joined to the center electrode via a molten bond; an insulator holding the center electrode; a metal shell holding the insulator; and a ground electrode joined to the metal shell. Relationships d?2.1 [mm] and ?0.09×d+0.33<Vb/(Va+Vb)<?0.2×d+0.75 are satisfied, where d is an outer diameter of the center electrode at a position 4 mm closer to the base end of the center electrode from the base end of the molten bond in the axial direction, and Va and Vb are volumes of the electrode base member and the core member, respectively, at a region between the base end of the molten bond and the position in the axial direction.

Abstract: The invention concerns with an exposure control mechanism for use in an image pickup apparatus in which a diaphragm aperture formed by a plurality of diaphragm blades moving straightforward in opposite directions is covered by an ND filter, and intends to prevent deterioration of image quality caused by diffraction even in an image pickup device having a small picture size and a short pixel pitch. The image pickup apparatus comprises an exposure control mechanism for adjusting the quantity of light flux entering a shooting lens system. The exposure control mechanism comprises a diaphragm made up of diaphragm blades movable on a plane perpendicular to an optical axis in opposite directions to define a diaphragm aperture, and an ND filter made up of at least two ND filter elements having different transmittances.

Abstract: A protrusion (21b) is formed on a central region of an inner surface (21c) of a first disc plate (21) constituting an end on an inclined lower side of a rotating drum (2). Particles (11) in the vicinity of the other end (first disc plate (21)), which are lifted forward in a rotational direction as the rotation drum (2) rotates, are brought into contact with a surface of the protrusion (21b) when the particles (11) flow backward in the rotational direction due to their own weights. Then, the particles (11) are guided by the surface of the protrusion (21b) to thereby flow toward the inclined upper side. As a result, a stagnation phenomenon of the particles (11) in the vicinity of the other end (first disc plate (21)) is less likely to occur.

Abstract: A method for producing activated carbon for electrodes of electric double layer capacitors is disclosed which comprises an activation step wherein activated carbon is obtained by mixing an alkali metal hydroxide with a carbon raw material for the activated carbon and heating the mixture in an inert gas atmosphere, a deactivation removal step wherein the alkali metal in the activated carbon is deactivated and removed, and a heat treatment step wherein the activated carbon having gone through the deactivation removal step is heated in an inert gas atmosphere at a temperature higher than 400° C. but not higher than the heating temperature in the activation step.

Abstract: The invention concerns with an exposure control mechanism for use in an image pickup apparatus in which a diaphragm aperture formed by a plurality of diaphragm blades moving straightforward in opposite directions is covered by an ND filter, and intends to prevent deterioration of image quality caused by diffraction even in an image pickup device having a small picture size and a short pixel pitch. The image pickup apparatus comprises an exposure control mechanism for adjusting the quantity of light flux entering a shooting lens system. The exposure control mechanism comprises a diaphragm made up of diaphragm blades movable on a plane perpendicular to an optical axis in opposite directions to define a diaphragm aperture, and an ND filter made up of at least two ND filter elements having different transmittances.

Abstract: The invention concerns with an exposure control mechanism for use in an image pickup apparatus in which a diaphragm aperture formed by a plurality of diaphragm blades moving straightforward in opposite directions is covered by an ND filter, and intends to prevent deterioration of image quality caused by diffraction even in an image pickup device having a small picture size and a short pixel pitch. The image pickup apparatus comprises an exposure control mechanism for adjusting the quantity of light flux entering a shooting lens system. The exposure control mechanism comprises a diaphragm made up of diaphragm blades movable on a plane perpendicular to an optical axis in opposite directions to define a diaphragm aperture, and an ND filter made up of at least two ND filter elements having different transmittances.

Abstract: An imaging apparatus with an exposure controlling mechanism being made to define an iris aperture by moving iris blades on surfaces perpendicular to an optical axis, wherein the exposure controlling mechanism includes a first iris blade to which a first ND filter having at least two levels of transmissivity is attached, a second iris blade to which no ND filter is attached, and a third iris blade to which a second ND filter having a single transmissivity is attached, and the first to the third iris blades are made to differ respectively in amounts and phases of their displacements caused by an operation of a driving means.

Abstract: A zoom lens comprising a first lens group having a positive refracting power and its position fixed, a second lens group having a negative refracting power and displacable mainly for magnification, a third lens group having a positive refracting power and its position fixed, and a fourth lens group having a positive refracting power and displacable mainly for correction of the focal position for magnification and focusing.

Abstract: A multilayer ceramic capacitor is produced by using a dielectric ceramic composition prepared by allowing a composition represented by the composition formula (Ba.sub.1-x Ca.sub.x)TiO.sub.3 (provided that 0.005.ltoreq.x.ltoreq.0.05), namely, 0.5-5 mol % to contain an additive of MnO--CoO--MgO at 0.2 to 2 mol % and a Y.sub.2 O.sub.3 additive at 2.5 mol % or less and further adding a glass component comprising SiO.sub.2 --Al.sub.2 O.sub.3 --BaO--CaO--Ta.sub.2 O.sub.5 at 0.5 to 5 mol % to the resulting composition. The dielectric ceramic composition can be prepared into slurry well by using an aqueous binder and can be sintered well with no occurrence of any crack even by fast firing, and even after barrel treatment, additionally, chipping hardly occurs in the dielectric ceramic composition. Accordingly, the resulting multilayer ceramic capacitor exerts an excellent breakdown voltage even at a large size and can therefore satisfy the JIS B characteristic.

Abstract: A zoom lens is provided, in which a fixed first lens group having a positive refracting power, a second lens group having a negative refracting power and which realizes a variable magnification, a fixed third lens group having a positive refracting power and a fourth lens group having a positive refracting power which compensates fluctuation of an image surface caused by the variable magnification and which focuses an image are sequentially provided from an object side. In this zoom lens, the third lens group is composed of two separate lenses of a positive lens (31) and a negative lens (32). At least one surface of the positive lens (31) is formed as an aspherical surface and a surface of the negative lens (32) opposing the image surface side is concaved to the image surface side. Thus, the zoom lens of this invention can be miniaturized and reduced in weight without deteriorating the characteristics such that a variable magnification is large and that an F number is small.