Abstract: A thrust magnetic bearing device includes: a thrust disc fixed to a rotating body; and a pair of electromagnets provided so as to sandwich the thrust disc and be spaced apart from the thrust disc in a direction along a rotation axis. Each of the pair of electromagnets includes: a coil wound around the rotation axis of the rotating body; and a ring-shaped core accommodating the coil. The core includes a slit which is located at at least one circumferential position of the core and extends from an outside outer peripheral surface as a starting point toward a center of the core. The slit is formed in a range including at least an inside outer peripheral surface.

Abstract: A thrust magnetic bearing device includes: a thrust disc fixed to a rotating body; and a pair of electromagnets provided so as to sandwich the thrust disc and be spaced apart from the thrust disc in a direction along a rotation axis. Each of the pair of electromagnets includes: a coil wound around the rotation axis of the rotating body; and a ring-shaped core accommodating the coil. The core includes a slit which is located at at least one circumferential position of the core and extends from an outside outer peripheral surface as a starting point toward a center of the core. The slit is formed in a range including at least an inside outer peripheral surface.

Abstract: The solution of a constrained optimization problem is easily solved by linearly approximating a point of interest to a first hypersurface given as a constraint and finding the extreme value of the objective function by moving a point r along a curved line having second-order osculation with the geodetic line of a hypersurface S(r)=c and passing through the point r.

Abstract: The solution of a constrained optimization problem is easily solved by linearly approximating a point of interest to a first hypersurface given as a constraint and finding the extreme value of the objective function by moving a point r along a curved line having second-order osculation with the geodetic line of a hypersurface S(r)=c and passing through the point r.

Abstract: An inorganic thermochromic substance is proposed which is a composite oxide of strontium and manganese in a specified molar ratio as prepared by the calcination of a powder blend of strontium carbonate and manganese dioxide, instead of conventional manganese carbonate, at a specified temperature for a specified length of time. The temperature of the thermochromic color change is about -130.degree. C., much lower than the color-change point of most of conventional thermochromic substances. The color of the composite oxide is grey or pale green at room temperature but reversibly changes to pale red when it is chilled to -130.degree. C. or lower.