Abstract: A bulk-acoustic wave (BAW) resonator includes a central portion in which a first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on a substrate, and an extension portion extending externally from the central portion, and an insertion layer and a loss prevention film are disposed in the extension portion between the substrate and the second electrode. The loss prevention film is formed to have a thickness of 50 ? to 500 ?. The insertion layer is stacked on the loss prevention film, and has a side surface opposing the central portion, the side surface is formed as a first inclined surface having a first inclination angle. The loss prevention film has a side surface opposing the central portion, the side surface is formed as a second inclined surface having a second inclination angle. The second inclination angle is formed to be greater than the first inclination angle.

Abstract: Provided is an apparatus and method for performing tertiary treatment of sewage based on porous filtering media. The apparatus for performing tertiary treatment of sewage based on porous filtering media includes a reaction tank for receiving effluent wastewater from a primary settling tank; and porous filtering media, which is located in the reaction tank and has a predetermined size of surface area and opening, for settling suspension in the effluent wastewater and removing organic matter and nutritive salts included in the suspension.

Abstract: Provided is an apparatus and method for performing tertiary treatment of sewage based on porous filtering media. The apparatus for performing tertiary treatment of sewage based on porous filtering media includes a reaction tank for receiving effluent wastewater from a primary settling tank; and porous filtering media, which is located in the reaction tank and has a predetermined size of surface area and opening, for settling suspension in the effluent wastewater and removing organic matter and nutritive salts included in the suspension.

Abstract: A status displaying device includes a plurality of modules each having a plurality of channels to display system status. The status displaying device comprises a plurality of LEDs corresponding to the number of the channels so as to display the system status by changing colors of the LEDs according to the module states.