Abstract: A removable fastening system includes a rail unit located in a vehicle, an electrode portion located at the inner side of the rail unit, a fixing unit having one end inserted to be fixed to the rail unit, and a mounting unit mounted at another end of the fixing unit, wherein the fixing unit is inserted into the rail unit and has a conductive portion rotated to be brought into contact with the electrode portion.

Abstract: Disclosed is a thulium-containing fluorescent substance for a white light emitting diode represented by a following chemical formula 1, (Chemical Formula 1) (M1-X-J7EuxTnIy)2SiO4 where M is a divalent cation metal including Sr or Ba, with 0.005<x<0.05 and 0.005<y<0.05. The silicate-based yellow fluorescent substance according to the present invention is sufficiently excited by a blue light source generated by a blue LED to exhibit a yellow emission, with superior luminous intensity, due to the addition of europium oxide (Eu2O3) and thulium oxide (Tm2O3) as an activator, thereby being suitable for a white LED.

Abstract: Disclosed is a thulium-containing fluorescent substance for a white light emitting diode represented by a following chemical formula 1, (Chemical Formula 1) (M1-X-J7EuxTnIy)2SiO4 where M is a divalent cation metal including Sr or Ba, with 0.005<x<0.05 and 0.005<y<0.05. The silicate-based yellow fluorescent substance according to the present invention is sufficiently excited by a blue light source generated by a blue LED to exhibit a yellow emission, with superior luminous intensity, due to the addition of europium oxide (Eu2O3) and thulium oxide (Tm2O3) as an activator, thereby being suitable for a white LED.