Abstract: A detection apparatus for an eddy current in a heat generating tube using a permeability measurement method, and a method using the apparatus are provided. In the detection apparatus, a bobbin type probe acquires detection information with respect to a magnetic flux change by a magnetic phase occurring in the heat generating tube using a coil which is wound in an axis direction of at least one yoke located in a perpendicular direction with a bobbin of the bobbin type probe, and a material having a corresponding magnetic phase and a circumferential defect, which is difficult to be detected by the bobbin type probe, are detected based on the detection information.

Abstract: A detection apparatus for an eddy current in a heat generating tube using a permeability measurement method, and a method using the apparatus are provided. In the detection apparatus, a bobbin type probe acquires detection information with respect to a magnetic flux change by a magnetic phase occurring in the heat generating tube using a coil which is wound in an axis direction of at least one yoke located in a perpendicular direction with a bobbin of the bobbin type probe, and a material having a corresponding magnetic phase and a circumferential defect, which is difficult to be detected by the bobbin type probe, are detected based on the detection information.

Abstract: The present invention relates to titanium dioxide powder with a large specific surface area, a method for preparing thereof, and a use of the titanium dioxide as a photocatalyst, and more particularly, discloses a method for the preparation of titanium dioxide powder comprised of the steps of adding ice pieces or icy distilled water to pure titanium tetrachloride (TiCl4) to give an aqueous titanylchloride solution of 1.5 M or higher; diluting the aqueous titanylchloride with distilled water; obtaining precipitates from the diluted aqueous titanylchloride solution by standing for 2-20 hours at 15-70° C.; and filtering, washing and drying the above precipitates to give downy hair-shaped TiO2 powder with a specific surface area of 130-200 m2/g.