Abstract: To reduce the roughening of a surface of a workpiece whose hardness is increased by heat treatment. In a workpiece such as a guide plate (11), not a surface (11a1) of a groove (11a) that is a desired part for hardening (hardening target position) but a surface (11a2) opposite the surface (11a1) is heat-treated as a surface to be heated that is to be directly heated by an induction heating device. This can inhibit the surface (11a1) of the hardening target position from being roughened by the heat treatment and becoming lower in surface precision than before the heat treatment. Further, according to the present invention, the use of the induction heating device makes it possible to heat-treat only a necessary part.

Abstract: Stable isotope atoms present in the form of stable isotope compounds, for example, 13C present in the form of 13CO, are separated by distillation using a distillation column packed orderly with a formed packing, and preferably by distillation using a distillation column packed with a “promoting-fluid-dispersion type” structured packing.