Abstract: To make validity of a prediction model created by machine learning be able to be verified with appropriate accuracy and efficiency. A software test apparatus includes a storage device configured to store a prediction model, and an arithmetic device. The arithmetic device is configured to accept inputs of a precondition, a constraint condition, and an approximation threshold value, convert the prediction model into a logical expression, analyze an approximation range based on the approximation threshold value with respect to the logical expression to simplify the logical expression, generate an inspection expression by combining the simplified logical expression with the precondition and negation of the constraint condition, search for, as a counterexample, a value satisfying the inspection expression, input the value to the prediction model to evaluate inspection accuracy when the counterexample exists, and output a result of the evaluation.

Abstract: A heating member includes a ceramic substrate having a structure in which a plurality of ceramic layers are laminated together; a resistance heat-generating element embedded in the ceramic substrate; an electricity supply element disposed on a surface of the ceramic substrate; and an electricity supply path embedded in the ceramic substrate and electrically connecting the resistance heat-generating element and the electricity supply element. The electricity supply path includes a plurality of conductive layers disposed along the planar direction of the ceramic layers at different positions in the thickness direction of the ceramic substrate, and a plurality of vias disposed along the thickness direction of the ceramic substrate. When the plurality of conductive layers are viewed from the thickness direction, their outer edges are positionally offset from one another.

Abstract: A heating member includes a ceramic substrate having a structure in which a plurality of ceramic layers are laminated together; a resistance heat-generating element embedded in the ceramic substrate; an electricity supply element disposed on a surface of the ceramic substrate; and an electricity supply path embedded in the ceramic substrate and electrically connecting the resistance heat-generating element and the electricity supply element. The electricity supply path includes a plurality of conductive layers disposed along the planar direction of the ceramic layers at different positions in the thickness direction of the ceramic substrate, and a plurality of vias disposed along the thickness direction of the ceramic substrate. When the plurality of conductive layers are viewed from the thickness direction, their outer edges are positionally offset from one another.

Abstract: A ceramic dynamic-pressure bearing includes a first member 14 having a cylindrical outer surface and a second member 15 having a cylindrical reception hole formed therein. The first member 14 is inserted into the reception hole. A radial dynamic-pressure gap is formed between the inner surface of the reception hole of the second member 15 and the outer circumferential surface of the first member 14. The first member 14 and the second member 15 are formed of an alumina ceramic which contains an Al component in an amount of 90–99.5% by mass as reduced to Al2O3 and an oxide-type sintering aid component in an amount of 0.5–10% by mass as reduced to an oxide thereof. The thrust dynamic-pressure gap definition surface of the second member which faces the thrust plate has a flatness of not greater than 3 ?m or the thrust dynamic-pressure gap definition surface of the thrust plate which faces the second member has a flatness of not greater than 3 ?m.

Abstract: A ceramic dynamic-pressure bearing having dynamic-pressure grooves. At least a portion including a surface (dynamic-pressure gap definition surface) facing a dynamic-pressure gap is formed of ceramic, and dynamic-pressure grooves GV are formed, by electrolytic etching, on the ceramic dynamic-pressure gap definition surface such that, on a cross section of the groove GV taken perpendicular to the longitudinal direction of the groove GV, a curvature portion R having a radius of 3-7 &mgr;m is formed at a meeting position where a groove sidewall surface SG and a groove bottom surface BG meet. In a preferred embodiment, a large number of pores K are formed on one or more of the rotary surfaces M of the dynamic-pressure bearing formed of ceramic such that the surface porosity falls in the range of 10 to 60%.

Abstract: A ceramic dynamic pressure bearing, includes: a first member having an outer periphery formed with a gap forming surface causing a radial dynamic pressure, and a second member having an inner periphery defining a through hole formed with a gap forming surface causing the radial dynamic pressure. The first member is inserted into the through hole as to form a radial gap. The first member and the second member make rotation relative to each other to cause a fluid dynamic pressure at the radial gap. The first member and the second member are composed of an alumina ceramic including: an aluminum 90% to 99.5% by weight, and an oxide sintering assistant 0.5% to 10% by weight. The outer periphery has cylindricity not larger than 1.0 &mgr;m, and roundness not larger than 0.5 &mgr;m. The inner periphery has cylindricity not larger than 1.5 &mgr;m, and roundness not larger than 1.0 &mgr;m.

Abstract: A ceramic dynamic-pressure bearing which is not prone to wear or a like problem associated with starting, stopping, or a like operation mode and which can realize smooth rotation. A dynamic-pressure gap 17 is formed between a first member 14 and a second member 15, which undergo relative rotation about a predetermined axis of rotation. The relative rotation of the first member 14 and the second member 15 generate fluid dynamic-pressure in the dynamic-pressure gap 17. At least a portion of one or both of the first member 14 and the second member 15 includes a polished surface (a dynamic-pressure gap definition surface) formed of alumina ceramic facing the dynamic-pressure gap 17, and the alumina ceramic, which forms the dynamic-pressure gap definition surface finished by polishing, is adjusted to have an apparent density of 3.5-3.9 g/cm3. Also disclosed is a motor, hard disk drive and polygon scanner containing the bearing.

Abstract: A ceramic dynamic pressure bearing comprising a first member and a second member, wherein the first member and the second member define a dynamic pressure gap therebetween, the first member and the second member relatively rotate around an axis of rotation, the relative rotation generates a fluid dynamic pressure in the dynamic pressure gap, the first member has a first surface directing to the dynamic pressure gap and the second member has a second surface directing to the dynamic pressure gap, and at least one of the first and second surfaces comprises ceramic, the ceramic comprises: a ceramic matrix that is selected from alumina ceramic, zirconia ceramic and silicon nitride ceramic; and 15 vol % to 70 vol % of an electrically-conductive inorganic compound phase based on the total amount of the ceramic, the phase is dispersed in the ceramic matrix, the phase comprises at least one compound selected from tungsten carbide, silicon carbide, conductive oxide, metallic nitride, metallic carbide, metallic boride,

Abstract: A ceramic dynamic-pressure bearing includes a first member 14 having a cylindrical outer surface and a second member 15 having a cylindrical reception hole formed therein. The first member 14 is inserted into the reception hole. A radial dynamic-pressure gap is formed between the inner surface of the reception hole of the second member 15 and the outer circumferential surface of the first member 14. The first member 14 and the second member 15 are formed of an alumina ceramic which contains an Al component in an amount of 90-99.5% by mass as reduced to Al2O3 and an oxide-type sintering aid component in an amount of 0.5-10% by mass as reduced to an oxide thereof. The thrust dynamic-pressure gap definition surface of the second member which faces the thrust plate has a flatness of not greater than 3 &mgr;m or the thrust dynamic-pressure gap definition surface of the thrust plate which faces the second member has a flatness of not greater than 3 &mgr;m.

Abstract: A ceramic dynamic-pressure bearing having dynamic-pressure grooves. At least a portion including a surface (dynamic-pressure gap definition surface) facing a dynamic-pressure gap is formed of ceramic, and dynamic-pressure grooves GV are formed, by electrolytic etching, on the ceramic dynamic-pressure gap definition surface such that, on a cross section of the groove GV taken perpendicular to the longitudinal direction of the groove GV, a curvature portion R having a radius of 3-7 &mgr;m is formed at a meeting position where a groove sidewall surface SG and a groove bottom surface BG meet. In a preferred embodiment, a large number of pores K are formed on one or more of the rotary surfaces M of the dynamic-pressure bearing formed of ceramic such that the surface porosity falls in the range of 10 to 60%.

Abstract: A ceramic dynamic pressure bearing comprising a first member and a second member, wherein the first member and the second member define a dynamic pressure gap therebetween, the first member and the second member relatively rotate around an axis of rotation, the relative rotation generates a fluid dynamic pressure in the dynamic pressure gap, the first member has a first surface directing to the dynamic pressure gap and the second member has a second surface directing to the dynamic pressure gap, and at least one of the first and second surfaces comprises ceramic, the ceramic comprises: a ceramic matrix that is selected from alumina ceramic, zirconia ceramic and silicon nitride ceramic; and 15 vol % to 70 vol % of an electrically-conductive inorganic compound phase based on the total amount of the ceramic, the phase is dispersed in the ceramic matrix, the phase comprises at least one compound selected from tungsten carbide, silicon carbide, conductive oxide, metallic nitride, metallic carbide, metallic boride,

Abstract: A ceramic dynamic pressure bearing, includes: a first member having an outer periphery formed with a gap forming surface causing a radial dynamic pressure, and a second member having an inner periphery defining a through hole formed with a gap forming surface causing the radial dynamic pressure. The first member is inserted into the through hole as to form a radial gap. The first member and the second member make rotation relative to each other to cause a fluid dynamic pressure at the radial gap. The first member and the second member are composed of an alumina ceramic including: an aluminum 90% to 99.5% by weight, and an oxide sintering assistant 0.5% to 10% by weight. The outer periphery has cylindricity not larger than 1.0 &mgr;m, and roundness not larger than 0.5 &mgr;m. The inner periphery has cylindricity not larger than 1.5 &mgr;m, and roundness not larger than 1.0 &mgr;m.