Abstract: An optical element is composed of a first substrate and a second substrate that are joined to each other. The first substrate is composed of a plurality of transparent base materials joined to each other through a first joint surface on which an optical film is formed. The second substrate is composed of a plurality of transparent base materials joined to each other through at least two second joint surfaces parallel to each other. On each of the second joint surfaces, an optical film is formed. One part of light incident on the first substrate is reflected from the first joint surface to be incident on the second substrate, and at least one part thereof is reflected from at least one of the second joint surfaces. A virtual plane including an incident light axis and a reflected light axis on the first joint surface and a virtual plane including incident light axes and reflected light axes on the respective second joint surfaces form an angle of substantially 45 degrees.

Abstract: A case hardening steel high in impact strength, consists essentially of carbon in an amount of from 0.1 to 0.3% by weight, silicon in an amount of from more than 0.3 to 1.0% by weight, manganese in an amount of from 0.3 to 1.7% by weight, phosphorus in an amount of not more than 0.03% by weight, sulfur in an amount of not more than 0.03% by weight, molybdenum in an amount of not more than 1.0% by weight, aluminum in an amount of not more than 0.04% by weight, nitrogen in an amount of not more than 0.03% by weight, and balance being iron and inevitable impurities. The case hardening steel meets an equation of [C %]+5([P %]+[S %])≦([Mn %]+[Mo %]+1.8)/8.

Abstract: Nickel powder herein disclosed is characterized in that it has an average particle size as determined through the observation by a scanning electron microscope (SEM) ranges from 0.1 to 1 &mgr;m and that the D5 0 value as determined by laser diffraction-scattering particle size distribution analysis and the average particle size as determined by SEM observation satisfy the following relation represented by Formula (1): 1≦[(D5 0 value)/(average particle size as determined by SEM observation)]≦1.8  (1) The nickel powder is highly dispersible in an organic vehicle during the preparation of a conductive paste because it has low agglomerate properties and it is in an approximately monodispersed condition and the nickel powder is particularly suitable in the preparation of a conductive paste for use in making a thin internal electrode of a multilayer ceramic capacitor, which is free of any projection, because of it sharp particle distribution.

Abstract: The composite nickel fine powder includes surface-oxidized nickel fine particles and at least one member selected from the group consisting of oxides and complex oxides of at least one metal element having an atomic number ranging from 12 to 56 or 82 and belonging to Group 2 to 14 of the Periodic Table on the surface of the surface-oxidized nickel fine particles.

Abstract: A plurality of detecting means 37, 38, 39, 40 are installed to detect a plurality of type specifying factors of work sheets W. A work sheet type identifying means 41 is installed to identify the types of the work sheets based on the factors detected by the detecting means 37˜40. A parameter selection means 42 is installed to select control parameters in accordance with the work sheet type identified by the work sheet type identifying means 41. A process control means 32 controls a processing means 3 based on the control parameters thus selected. The parameter selection means 42 is composed of a parameter memory means 44 and a parameter selection section 43. Said control parameters include a speed pattern of the ram, a hover height of the ram, a press torque in form-processing, and a number of tons for punching.

Abstract: An optical head comprises a photodetector 8 having divided photosensitive areas to detect light 13 reflected from an optical disk 7, means 10, 11, 12 for obtaining tracking error signal by operating signals from the photosensitive areas. The photodetector 8 has a first division line 9a parallel to an information track on the optical disk and second and third division lines 9b, 9c perpendicular to the first division line 9f and symmetrical to the optical axis. Further, a light-shielding area 8i is provided for shielding a part of the reflected light between the division lines 9b and 9c. The signals are operated to reduce offset of the tracking error signal due to a shift of object lens and a tilt of the optical disk. Accordingly, the optical head of the present invention has a small offset of tracking error signal with a simple structure.

Abstract: Nickel powder herein disclosed has an average particle size, as determined by the observation with SEM, of not more than 1 &mgr;m, a particle density of not less than 8.0 g/cm3, and an average diameter of crystallites present in the nickel particles of not more than 550 Å. Moreover, a conductive paste for a multilayer ceramic capacitor comprises the foregoing nickel powder. The nickel powder and the conductive paste containing the same can control heat shrinkage while inhibiting any rapid oxidation and permit the production of a thin, uniform internal electrode for a multilayer ceramic capacitor without being accompanied by any crack formation and delamination during firing.

Abstract: Copper fine powder has an electrical resistance in its powdery state of not more than 1×10−3 &OHgr;·cm; a BET specific surface area ranging from 0.15 to 0.3 m2/g; a tap density of not less than 4.5 g/cc; a product of the tap density and the particle size, of not less than 13, the particle size being calculated from the specific surface area and; a particle size distribution observed in the microtrack measurement as expressed in terms of D50 and D90 ranging from 4 to 7 &mgr;m and 9 to 11 &mgr;m, respectively; and a weight loss through hydrogen-reduction of not more than 0.30%. The copper fine powder is prepared by adding an alkali hydroxide to an aqueous copper salt solution containing divalent copper ions maintained at not less than 55° C. in an amount of not less than the chemical equivalent to form cupric oxide; then gradually adding a reducing sugar to the reaction system while maintaining the temperature of the system to not less than 55° C.

Abstract: The composite nickel fine powder includes surface-oxidized nickel fine particles and at least one member selected from the group consisting of oxides and complex oxides of at least one metal element having an atomic number ranging from 12 to 56 or 82 and belonging to Group 2 to 14 of the Periodic Table on the surface of the surface-oxidized nickel fine particles.

Abstract: An epoxy resin composition of the invention comprises: an epoxy resin; a hardening agent; and a phenol-modified polyphenylene oxide having a number average molecular weight of 1000 to 4000, which is prepared by carried out a redistribution reaction between a polyphenylene oxide and a phenol compound in the presence of a reaction initiator which can be decomposed to generate an alcohol, a prepreg and a metal-clad laminate of the invention contain the epoxy resin composition.

Abstract: An optical head comprises a photodetector 8 having divided photosensitive areas to detect light 13 reflected from an optical disk 7, means 10, 11, 12 for obtaining tracking error signal by operating signals from the photosensitive areas. The photodetector 8 has a first division line 9a parallel to an information track on the optical disk and second and third division lines 9b, 9c perpendicular to the first division line 9f and symmetrical to the optical axis. Further, a light-shielding area 8i is provided for shielding a part of the reflected light between the division lines 9b and 9c. The signals are operated to reduce offset of the tracking error signal due to a shift of object lens and a tilt of the optical disk. Accordingly, the optical head of the present invention has a small offset of tracking error signal with a simple structure.

Abstract: Nickel powder herein disclosed is characterized in that it has an average particle size as determined through the observation by a scanning electron microscope (SEM) ranges from 0.

Abstract: A plurality of detecting means 37, 38, 39, 40 are installed to detect a plurality of type specifying factors of work sheets W. A work sheet type identifying means 41 is installed to identify the types of the work sheets based on the factors detected by the detecting means 37˜40. A parameter selection means 42 is installed to select control parameters in accordance with the work sheet type identified by the work sheet type identifying means 41. A process control means 32 controls a processing means 3 based on the control parameters thus selected. The parameter selection means 42 is composed of a parameter memory means 44 and a parameter selection section 43. Said control parameters include a speed pattern of the ram, a hover height of the ram, a press torque in form-processing, and a number of tons for punching.

Abstract: Nickel powder herein disclosed has an average particle size, as determined by the observation with SEM, of not more than 1 &mgr;m, a particle density of not less than 8.0 g/cm3, and an average diameter of crystallites present in the nickel particles of not more than 550 Å. Moreover, a conductive paste for a multilayer ceramic capacitor comprises the foregoing nickel powder. The nickel powder and the conductive paste containing the same can control heat shrinkage while inhibiting any rapid oxidation and permit the production of a thin, uniform internal electrode for a multilayer ceramic capacitor without being accompanied by any crack formation and delamination during firing.

Abstract: An optical head comprises a photodetector 8 having divided photosensitive areas to detect light 13 reflected from an optical disk 7, means 10, 11, 12 for obtaining track error signal by operating signals from the photosensitive areas. The photodetector 8 has a first division line 9a parallel to an information track on the optical disk and second and third division lines 9b, 9c perpendicular to the first division line 9f and symmetrical to the optical axis. Further, a light-shielding area 8i is provided for shielding a part of the reflected light between the division lines 9b and 9c. The signals are operated to reduce offset of the tracking error signal due to a shift of object lens and a tilt of the optical disk. Accordingly, the optical head of the present invention has a small offset of tracking error signal with a simple structure.

Abstract: Nickel fine powder comprises nickel and phosphorus dispersed in the nickel in an amount ranging from 0.01 to 2% by weight on the basis of the weight of the nickel and having a particle size of not more than 0.5 &mgr;m. The nickel fine powder can be prepared by a method comprising the step of reducing nickel hydroxide in the presence of phosphorus ions in such an amount that the molar ratio of phosphorus ions to nickel ions falls within the range of from 0.01 to 2.

Abstract: An optical head is composed of an objective 2, a composite diffraction element 3 having six areas divided by three parting lines 3a to 3c; and a substrate 5 on which a light-emitting element and a plurality of light-receiving elements are arranged. A focus and a tracking error signals are generated based on signals from the light-receiving elements that receive those of a plurality of luminous fluxes divided by the composite diffraction element 3 which result from passage through the portion between the parting lines 3b and 3c. In generating the tracking error signal, signals from the light-receiving elements that receive luminous fluxes resulting from passage through the outside of the parting lines 3b and 3c are used to correct an offset in the tracking error signal caused by the movement of the objective.

Abstract: Copper fine powder has an electrical resistance in its powdery state of not more than 1×10−3&OHgr;.cm; a BET specific surface area ranging from 0.15 to 0.3 m2/g; a tap density of not less than 4.5 g/cc; a product of the tap density and the particle size, of not less than 13, the particle size being calculated from the specific surface area and a particle size distribution observed in the microtrack measurement as expressed in terms of D50 and D90 ranging from 4 to 7 &mgr;m and 9 to 11 &mgr;m, respectively; and a weight loss through hydrogen-reduction of not more than 0.30%. The copper fine powder is prepared by adding an alkali hydroxide to an aqueous copper salt solution containing divalent copper ions maintained at not less than 55° C. in an amount of not less than the chemical equivalent to form cupric oxide; then gradually adding a reducing sugar to the reaction system while maintaining the temperature of the system to not less than 55° C.

Abstract: A nickel fine powder includes 0.02 to 1.0% by weight of magnesium and/or 0.02 to 0.1% by weight of calcium dispersed in the nickel. A method for preparing the nickel fine powder includes the steps of forming nickel hydroxide by mixing an aqueous solution containing a magnesium salt and/or a calcium salt and a nickel salt with an aqueous solution of sodium hydroxide and then reducing the hydroxide with a hydrazine reducing agent. The nickel fine powder has thermal shrinkage characteristics very close to those observed for ceramic substrates and is accordingly suitable as a material for producing an internal electrode for laminated ceramic condensers.

Abstract: A method for preparing nickel fine powder is herein disclosed, which comprises the steps of mixing an aqueous sodium hydroxide solution comprising, on the basis of the total weight of the sodium hydroxide present in the aqueous solution, 75 to 85% by weight of liquid caustic soda as specified in JIS K 1203 and 25 to 15% by weight, in total, of at least one of sodium hydroxide as specified in JIS K 8576 and solid caustic soda as specified in JIS K 1202, with an aqueous solution of nickel sulfate to form nickel hydroxide, then reducing the resulting nickel hydroxide with hydrazine and recovering nickel fine powder produced. The nickel fine powder prepared by the method has an average particle size of the primary particles ranging from 0.1 to 0.9 .mu.m, a D.sub.90 value of not more than 2.1 .mu.m and a tap density of not less than 3.5 g/cc.