Abstract: The present invention provides a rotating-body support structure that is capable of obtaining a damping effect of a rotating body with a simple configuration. To this end, the rotating-body support structure is configured to include a housing (21) and a bush portion (24) which is supported by the housing (21) and which rotatably supports a boring bar (11); and to have oil filled between the housing (21) and the bush portion (24).

Abstract: A deep-hole drilling apparatus capable of preventing a tool mark from growing is provided. The deep-hole drilling apparatus provided for this purpose comprises: a tool (12) that is rotationally driven to drill a deep hole (Wa) in a work (W); an acceleration meter (19) that detects vibration of the tool (12) as the acceleration during deep hole processing; a monitoring apparatus (20) which performs frequency analysis on the acceleration detected by the acceleration meter (19) and which determines that a tool mark is produced in the deep hole (Wa) when the overall value of the whirling frequency and the bending natural frequency within a frequency range not including the torsional natural frequency on torsional vibration, constantly produced during the deep hole processing, exceeds a predetermined threshold (?); and an NC apparatus (18) that controls both revolution and feeding speed of the tool (12) on the basis of the determination made by the monitoring apparatus (20).

Abstract: An object of the invention is to provide a sodium refining apparatus which has a simple constitution and does not deteriorate a solid electrolyte employed therein. The sodium refining apparatus of the invention, in which impurities contained in sodium are removed by a solid electrolyte having sodium ion conductivity, includes a bottom-closed casing made of a solid electrolyte and containing a small amount of highly pure sodium; an outer casing accommodating said bottom-closed casing and containing, outside said bottom-closed casing, impurity-containing sodium; a first electrode inserted in the impurity-containing sodium; a second electrode inserted in the highly pure sodium; and a power source for applying DC voltage to the electrodes; wherein the impurity-containing sodium and the highly pure sodium are in electrical contact with each other via the solid electrolyte.

Abstract: An object of the invention is to provide a sodium refining apparatus which has a simple constitution and does not deteriorate a solid electrolyte employed therein. The sodium refining apparatus of the invention, in which impurities contained in sodium are removed by a solid electrolyte having sodium ion conductivity, includes a bottom-closed casing made of a solid electrolyte and containing a small amount of highly pure sodium; an outer casing accommodating said bottom-closed casing and containing, outside said bottom-closed casing, impurity-containing sodium; a first electrode inserted in the impurity-containing sodium; a second electrode inserted in the highly pure sodium; and a power source for applying DC voltage to the electrodes; wherein the impurity-containing sodium and the highly pure sodium are in electrical contact with each other via the solid electrolyte.