Abstract: Provided are use of a rare earth amino acid complex, a polylactic acid composition and a preparation method thereof. The rare earth amino acid complex is formed by complexing a rare earth metal ion with an amino acid; a rare earth element corresponding to the rare earth metal ion is one or more selected from the group consisting of lanthanum, cerium and samarium; and the amino acid is at least one selected from the group consisting of proline, L-phenylalanine, tyrosine and tryptophan.

Abstract: The present invention discloses a method and system for determining a horizontal distance between a transmitting point and a receiving point. The method obtains a depth value of the transmitting point and a depth value of the receiving point. An area of a sound velocity profile according to the depth value of the transmitting point and the depth value of the receiving point is then determined. A sound velocity gradient according to the area of the sound velocity profile is also determined. The horizontal distance between the transmitting point and the receiving point according to the sound velocity gradient is then determined by calculations. The present invention eliminates the need to calculate a grazing angle of an eigen sound ray(wave) connecting the transmitting point and the receiving point, by directly converting a propagation time into the horizontal distance, thereby quickly and efficiently calculating the horizontal distance between the transmitting point and the receiving point.

Abstract: The present invention provides a method and system for real-time high-precision positioning in the deep sea. The present invention, based on a ray theory model, uses an azimuth angle, a transmission delay, a deep-sea vehicle depth and a depth of an acoustic transducer of a water surface monitoring platform as an eigenray emergence angle, an eigenray transmission time, eigenray emergence depth and an eigenray end point depth respectively, quickly calculates an eigenray that connects the water surface monitoring platform with the deep-sea vehicle, accurately calculates a position of the deep-sea vehicle relative to the water surface monitoring platform, and converts the position into absolute position information of the deep-sea vehicle through the latitude and longitude of the water surface monitoring platform, thereby achieving real-time high-precision positioning.

Abstract: The present invention discloses a method for determining an effective sound velocity in the deep sea. The method is applied to an apparatus for determining an effective sound velocity in the deep sea having a transmission point, a receiving point, and an underwater mobile carrier. The transmission point is installed on the sea surface such that the depth of the transmission point is unchanged. The receiving point is installed on the underwater mobile carrier such that the depth of the receiving point changes with movement of the underwater mobile carrier. The underwater mobile carrier can measure a sound velocity profile between the transmission point and the receiving point and a horizontal distance between the transmission point and the receiving point.

Abstract: An integrated method and system for communication, positioning, navigation, and timing of a deep-sea vehicle. The method implements integration and deep fusion of communication, positioning, navigation, and timing, and can achieve uniformity of space references and time references between sensors and systems, can reduce difficulty in information fusion, and can implement convenient underwater acoustic communication, real-time/high-update-rate/low-power-consumption/high-precision positioning, high-precision/fault-tolerant navigation, and precise timing. The present invention implements simultaneous operation of four working modes: communication, positioning, navigation, and timing, to fundamentally resolve problems such as insufficient practicability of underwater acoustic communication, low accuracy of navigation and positioning, and no timing function, so as to improve underwater operation efficiency of a deep-sea vehicle.

Abstract: The present invention discloses a method and system for determining a horizontal distance between a transmitting point and a receiving point. The method obtains a depth value of the transmitting point and a depth value of the receiving point. An area of a sound velocity profile according to the depth value of the transmitting point and the depth value of the receiving point is then determined. A sound velocity gradient according to the area of the sound velocity profile is also determined. The horizontal distance between the transmitting point and the receiving point according to the sound velocity gradient is then determined by calculations. The present invention eliminates the need to calculate a grazing angle of an eigen sound ray(wave) connecting the transmitting point and the receiving point, by directly converting a propagation time into the horizontal distance, thereby quickly and efficiently calculating the horizontal distance between the transmitting point and the receiving point.

Abstract: The present invention discloses a method for determining an effective sound velocity in the deep sea. The method is applied to an apparatus for determining an effective sound velocity in the deep sea having a transmission point, a receiving point, and an underwater mobile carrier. The transmission point is installed on the sea surface such that the depth of the transmission point is unchanged. The receiving point is installed on the underwater mobile carrier such that the depth of the receiving point changes with movement of the underwater mobile carrier. The underwater mobile carrier can measure a sound velocity profile between the transmission point and the receiving point and a horizontal distance between the transmission point and the receiving point.

Abstract: An integrated method and system for communication, positioning, navigation, and timing of a deep-sea vehicle. The method implements integration and deep fusion of communication, positioning, navigation, and timing, and can achieve uniformity of space references and time references between sensors and systems, can reduce difficulty in information fusion, and can implement convenient underwater acoustic communication, real-time/high-update-rate/low-power-consumption/high-precision positioning, high-precision/fault-tolerant navigation, and precise timing. The present invention implements simultaneous operation of four working modes: communication, positioning, navigation, and timing, to fundamentally resolve problems such as insufficient practicability of underwater acoustic communication, low accuracy of navigation and positioning, and no timing function, so as to improve underwater operation efficiency of a deep-sea vehicle.

Abstract: The present invention provides a method and system for real-time high-precision positioning in the deep sea. The present invention, based on a ray theory model, uses an azimuth angle, a transmission delay, a deep-sea vehicle depth and a depth of an acoustic transducer of a water surface monitoring platform as an eigenray emergence angle, an eigenray transmission time, eigenray emergence depth and an eigenray end point depth respectively, quickly calculates an eigenray that connects the water surface monitoring platform with the deep-sea vehicle, accurately calculates a position of the deep-sea vehicle relative to the water surface monitoring platform, and converts the position into absolute position information of the deep-sea vehicle through the latitude and longitude of the water surface monitoring platform, thereby achieving real-time high-precision positioning.