Abstract: A light-emitting device includes a semiconductor epitaxial structure including a first semiconductor layer, an active layer, and a second semiconductor layer, and having holes; a first insulation layer disposed on the semiconductor epitaxial structure and having first and second grooves; a first pad electrically connected to the first semiconductor layer through the first grooves; and a second pad electrically connected to the second semiconductor layer through the second grooves. A projection of the first pad does not overlap projections of the holes. A projection of the second pad does not overlap the projections of the holes. The first pad includes a first pad connection portion and first pad extension portions; the second pad includes a second pad connection portion and second pad extension portions. Projections of the second grooves fall between projections of the first and second pad extension portions. Two other aspects of the light-emitting device are also provided.

Abstract: Disclosed is a light-emitting device which includes a light-emitting element and a wavelength conversion layer, and light of a first wavelength emitted by the light-emitting element is converted into light of a second wavelength and light of a third wavelength through the wavelength conversion layer. The light-emitting element includes a first contact layer, and the reflectivity of the first contact layer to the third wavelength is greater than 85%, so that the reflectivity of the light of the second wavelength and the light of the third wavelength converted by the wavelength conversion layer and reflected to the surface of the light-emitting element may be increased, and the white light conversion efficiency and the light extraction efficiency of the light-emitting device are improved.

Abstract: A device and a method for detecting main acoustic indexes of multi-beam sonar pertaining to the field of hydrographic surveying and charting technology. The device includes a rotating device and a lifting gear installed in an anechoic tank. The bottom of the rotating device is equipped with a multi-beam sonar that has its rotating plane perpendicular to the direction of track line and transmits signals along the horizontal direction. A standard hydrophone is equipped at the bottom of the lifting gear, and is connected with a signal collector. The device utilizes the standard hydrophone to receive the pulse signals transmitted by the multi-beam sonar and employs the multi-beam sonar to receive the standard sound source signals, designs the detection process for data collection for analysis and research, thereby achieving the detection of the frequency, source level and beam angle of multi-beam sonar.

Abstract: A device and a method for detecting main acoustic indexes of multi-beam sonar pertaining to the field of hydrographic surveying and charting technology. The device includes a rotating device and a lifting gear installed in an anechoic tank. The bottom of the rotating device is equipped with a multi-beam sonar that has its rotating plane perpendicular to the direction of track line and transmits signals along the horizontal direction. A standard hydrophone is equipped at the bottom of the lifting gear, and is connected with a signal collector. The device utilizes the standard hydrophone to receive the pulse signals transmitted by the multi-beam sonar and employs the multi-beam sonar to receive the standard sound source signals, designs the detection process for data collection for analysis and research, thereby achieving the detection of the frequency, source level and beam angle of multi-beam sonar.