Abstract: In a brake-disc intermediate product, a corrugated portion is molded using an upper mold and a lower mold. The brake-disc intermediate product is set in a mold, the mold has a slope corresponding to the corrugated portion, and an angular portion formed along the outer circumferential edge of the corrugated portion is in contact with the slope in a state where the brake-disc intermediate product is set in the mold. The angular portion in contact with the slope is deformed by pressing the brake-disc intermediate product in a direction of the mold, to mold a chamfer portion. The slope is formed so that a chamfering angle formed with respect to an inner bottom surface of the mold is larger at a portion in contact with the concave portion than a chamfering angle at a portion in contact with the convex portion.

Abstract: In a brake-disc intermediate product, a corrugated portion is molded using an upper mold and a lower mold. The brake-disc intermediate product is set in a mold, the mold has a slope corresponding to the corrugated portion, and an angular portion formed along the outer circumferential edge of the corrugated portion is in contact with the slope in a state where the brake-disc intermediate product is set in the mold. The angular portion in contact with the slope is deformed by pressing the brake-disc intermediate product in a direction of the mold, to mold a chamfer portion. The slope is formed so that a chamfering angle formed with respect to an inner bottom surface of the mold is larger at a portion in contact with the concave portion than a chamfering angle at a portion in contact with the convex portion.

Abstract: A piezoelectric composition includes a compound represented by a general expression Bi4Ti3O12—SrBi4Ti4O15 as a main component; and Mn or a Mn compound as an additive. A Mn content is less than 1.0% by mass based on a main component amount.

Abstract: A zinc oxide semiconductor has a zinc oxide-based laminated structure including two layers of a zinc oxide layer with a lattice volume of Va and a donor concentration of Na, and a zinc oxide or zinc oxide solid solution layer with a lattice volume of Vb and a donor concentration of Nb. The relationships of Va<Vb and Na>Nb are satisfied. The layer with the lattice volume Va serves as a charge-supplying layer and the layer with the lattice volume Vb serves as a charge-receiving layer in the laminated structure. The charge is transferred from the layer serving as the charge-supplying layer to the layer serving as the charge-receiving layer even when no external electric field is applied to the laminated structure. A charge depletion layer is formed in the charge-supplying layer due to charge transfer from the charge-supplying layer to the charge-receiving layer.

Abstract: A brake disk producing method, comprising a periphery pressing step for forming an outer peripheral shape (5) of a rotor plate (2) into a peripheral shape having recesses and ridges (5a, 5b) repeated in a radial direction, and a chamfering step for forming a chamfered surface (6) by pressing, against a corner portion (2d) on an outer peripheral edge of the rotor plate (2), a die (7), and a brake disk made by the method. Accordingly, it is possible to improve heat radiation capability, reduce the weight and moment of inertia, improve safety in handling, and suppress increase in production costs. Furthermore, by forming the chamfered surface (6), the amount of wear of a brake pad pressed by the brake disk (1) can be reduced, and durability of braking performance can be maintained or improved.

Abstract: A piezoelectric ceramic 10 composed mainly of a three-component solid solution represented by the following general formula (1), wherein x, y and z in general formula (1) satisfy the following formulas (2), (3), (4) and (5). x(Bi1/2Na1/2)TiO3?y(Bi1/2Li1/2)TiO3?z(Bi1/2K1/2)TiO3??(1) 0.80?x?0.96??(2) 0.02?y?0.08??(3) 0.01?z?0.

Abstract: A piezoelectric composition includes a compound represented by a general expression Bi4Ti3O12—SrBi4Ti4O15 as a main component; and Mn or a Mn compound as an additive. A Mn content is less than 1.0% by mass based on a main component amount.

Abstract: A brake disk producing method, comprising a periphery pressing step for forming an outer peripheral shape (5) of a rotor plate (2) into a peripheral shape having recesses and ridges (5a, 5b) repeated in a radial direction, and a chamfering step for forming a chamfered surface (6) by pressing, against a corner portion (2d) on an outer peripheral edge of the rotor plate (2), a die (7), and a brake disk made by the method. Accordingly, it is possible to improve heat radiation capability, reduce the weight and moment of inertia, improve safety in handling, and suppress increase in production costs. Furthermore, by forming the chamfered surface (6), the amount of wear of a brake pad pressed by the brake disk (1) can be reduced, and durability of braking performance can be maintained or improved.

Abstract: A piezoelectric ceramic 10 composed mainly of a three-component solid solution represented by the following general formula (1), wherein x, y and z in general formula (1) satisfy the following formulas (2), (3), (4) and (5). x(Bi1/2Na1/2)TiO3-y(Bi1/2Li1/2)TiO3-z(Bi1/2K1/2)TiO3??(1) 0.80?x?0.96??(2) 0.02?y?0.08??(3) 0.01?z?0.

Abstract: The present invention is effective for causing charge separation by complexing zinc oxide crystals in different states one another when a zinc oxide semiconductor is used as an electronic element. The present invention provides a zinc oxide-based laminated structure comprising two layers of a zinc oxide or zinc oxide solid solution layer with a lattice volume of Va and a donor concentration of Na, and a zinc oxide or zinc oxide solid solution layer with a lattice volume of Vb and a donor concentration of Nb, wherein the relationships of Va<Vb and Na>Nb being satisfied between both layers of the laminated structures; and the layer with the lattice volume Va serves as a charge-supplying layer and the layer with the lattice volume Vb serves as a charge-receiving layer in the laminated structure.

Abstract: A brake disk producing method, comprising a periphery pressing step for forming an outer peripheral shape (5) of a rotor plate (2) into a peripheral shape having recesses and ridges (5a, 5b) repeated in a radial direction, and a chamfering step for forming a chamfered surface (6) by pressing, against a corner portion (2d) on an outer peripheral edge of the rotor plate (2), a die (7), and a brake disk made by the method. Accordingly, it is possible to improve heat radiation capability, reduce the weight and moment of inertia, improve safety in handling, and suppress increase in production costs. Furthermore, by forming the chamfered surface (6), the amount of wear of a brake pad pressed by the brake disk (1) can be reduced, and durability of braking performance can be maintained or improved.

Abstract: A lead-oxide-free piezoelectric ceramic composition having an electromechanical coupling coefficient greater than a predetermined value and having a Curie point of at least 500.degree. C., whose main component is a two-component-based solid solution of the formula of (1-x)Bi.sub.a Ti.sub.b Nb.sub.c O.sub.9 -xNa.sub.p Bi.sub.q Nb.sub.r O.sub.9, and which has a bismuth layer structure in the range of 0<x<1,the solid solution of the above formula satisfying 2.4<(1-x)a+xq<3.1,0<b<1.1,0.9<(1-x)c+xr<2.1, and0<p<0.6.

Abstract: One object of the present invention is to provide a lead-free piezoelectric material excellent in piezoelectric characteristics and superior from the viewpoints of prevention of environmental pollution, protection of environments and ecology. To achieve the object, a piezoelectric ceramic composition is constructed from a piezoelectric ceramic composition within a region in case of being represented by the formula:x[Bi.sub.1/2 Na.sub.1/2 ]TiO.sub.3 -y[MeNbO.sub.3 ]-(z/2)[Bi.sub.2 O.sub.3.Sc.sub.2 O.sub.3 ](wherein Me is K or Na)wherein X, y and z satisfy the following conditions:x+y+z=1, 0<x<1, 0.ltoreq.y<1, 0<z<0.5.

Abstract: A non-lead dielectric ceramic composition comprises a binary system solid solution represented as (1-x) BNT-xNN, wherein BNT is (Bi.sub.1/2 Na.sub.1/2)TiO.sub.3 and NN is NaNbO.sub.3, as constituents of the binary system solid solution, respectively, and 0<x<1. BNT is a ferroelectric material with a Curie temperature of 320.degree. C. and has a perovskite type crystal structure of a trigonal system. Meanwhile, NN is an anti-ferroelectric material having a perovskite type crystal structure of an orthorhombic system.

Abstract: A multilayer piezoelectric composite comprising a bonded laminate each layer of which is composed of a green sheet of a low-temperature sintering lead zirconate titanate piezoelectric ceramic. The temperature coefficient of a frequency constant of at least one layer has a polarity opposite to the polarity of those of the other layers. The bonded laminate is sintered at a temperature which does not produce any or almost any interdiffusion between layers so that the absolute value of the temperature coefficient of a frequency constant of the bonded laminate is smaller than the absolute value of the temperature coefficient of a frequency constant of any or one of the layers.

Abstract: A pyroelectric ceramic composition of the general formula: PbZr.sub.X (Zn.sub.1/3 Nb.sub.2/3).sub.Y Ti.sub.Z O.sub.3 wherein X+Y+Z=1 is provided having both of high pyroelectric constant and the second transition temperature below its Curie's temperature. Further, there is provided a multilayered pyroelectric structure comprising a stack of a plurality of layers, each of which has the different composition each to other, of the general formula: PbZr.sub.X (Zn.sub.1/3 Nb.sub.2/3).sub.Y Ti.sub.Z O.sub.3 wherein X+Y+Z=1, where the value of Z is different from each other in the different layers.