Abstract: A defect detecting apparatus for monitoring an electrical equipment for defects, the electrical equipment having a resonance frequency.

Abstract: An abnormality detecting method and apparatus for electrical equipment measures the frequency spectrum of a signal detected by a partial discharge sensor and detects a partial discharge signal having a frequency component in the neighborhood of a resonance frequency to detect the abnormality of the electrical equipment. The resonance frequency is determined on the basis of the electrical equipment and the measuring circuit. Where the electrical equipment is a rotating electric machine, the resonance frequency is determined on the basis of the length of the stator core, and a narrow bandpass filter circuit passes a frequency component around a resonance frequency to detect a partial discharge signal from the passed signal.

Abstract: A method of automatically growing a single crystal by using a floating-zone method in which radio-frequency induction heating is utilized, wherein the shape of molten zone of a sintered rod material is judged by comparing an anode voltage in a radio-frequency oscillation tube with a radio-frequency current, or a change in the shape of molten zone is judged depending of a change in a radio-frequency current during the growth of the sintered rod material, and power for heating is controlled on the basis of the judgement.

Abstract: The abnormality detecting method and apparatus for electric equipment measure the frequency spectrum of a signal detected by a partial discharge sensor 9, and detect a partial discharge signal having a frequency component in the neighborhood of a resonance frequency determined on the basis of the electric equipment and its measuring circuit, then detect the abnormality of the electric equipment. In a rotating electric machine particularly, the narrow band filter circuit 23 passes a frequency component around a resonance frequency determined on the basis of the length of the stator core to detect a partial discharge signal from the passed signal.

Abstract: It is an object of the present invention to obtain a high quality YB66 crystal by lowering the temperature of the molten zone and growing a crystal by deposition growth under an incongruent condition. A method for preparing a yttrium 66 boride crystal by the floating zone method by use of a YB66 polycrystalline rod. A YB66 crystal having a composition with an atomic ratio B/Y within a range of from 50 to 75, is grown under such conditions that the melt has a composition (an atomic ratio B/Y) different from the raw YB66 polycrystalline rod and the growing YB66 crystal, and that an equilibrium is maintained at the growth interface. When the atomic ratio B/Y of the starting material is within the range of from 50 to 62 and the atomic ratio B/Y of the melt is within the range of from 40 to 62, it is possible to attain the atomic ratio B/Y of the growing crystal within the range of from 50 to 62.

Abstract: The present invention relates to a lanthanum boride type single crystal having the chemical formula (La.sub.1-x M.sub.x)B.sub.6 (0.01.ltoreq.x.ltoreq.0.50) wherein M is at least one rare earth element selected from the group consisting of Ce, Pr, Nd, Sm and Gd, and further relates to a method for growing a lanthanum boride type single crystal by fusion method, which comprises using a lanthanum boride starting material containing from 1 to 50 mol % of at least one rare earth boride selected from the group consisting of CeB.sub.6, PrB.sub.6, NdB.sub.6, SmB.sub.6 and GdB.sub.6.

Abstract: A single crystal of lanthanum hexaboride is used as a tip of a thermionic emission cathode.