Abstract: Provided is a method for preparing a modified carboxymethyl chitosan, including the following steps: (1), weighing and adding a quality of chitosan to isopropanol (IA), subjecting a resulting mixture to swelling by stirring at room temperature for a period of time to obtain a swollen suspension; (2), subjecting the swollen suspension to alkalization at room temperature by adding a 40% NaOH solution to the swollen suspension; (3), heating a resulting alkalinized mixture by raising a temperature of a water bath to 60° C., and then slowly adding dropwise an isopropanol-chloroacetic acid (IA-MCA) mixture using a separatory funnel, subjecting an obtained mixture to reaction; and after the reaction is completed, adjusting a pH value of an obtained reaction product to about 7.0 using glacial acetic acid.

Abstract: Provided are a coal gangue soil amendment, and a preparation method and use thereof. The coal gangue soil amendment includes: a crushed coal gangue material, a crushed cornstalk material, a livestock manure, a compound microbial agent, and a water-absorbing and water-retaining particle, with a weight ratio of the crushed coal gangue material, the crushed cornstalk material, the livestock manure, the compound microbial agent, and the high molecular water-absorbing and water-retaining particle being 50:20:5:3:1, where the coal gangue soil amendment is applied to soil at a weight ratio of 5 g/kg.

Abstract: It is provided a joint receiver and receiving method for navigation signals located at adjacent frequencies. The joint receiving method includes: receiving a first navigation signal and a second navigation signal which are located at adjacent frequencies (S1); and calculating a frequency estimation of a virtual wideband navigation signal constructed based on the first navigation signal and the second navigation signal (S2), wherein the virtual wideband navigation signal is an asymmetric BOC-like navigation signal having a virtual carrier and a virtual sub-carrier. With the joint receiver and joint receiving method, not only power gain but also bandwidth gain can be obtained, and the ranging precision can be significantly improved.

Abstract: It is provided a joint receiver and receiving method for navigation signals located at adjacent frequencies. The joint receiving method includes: receiving a first navigation signal and a second navigation signal which are located at adjacent frequencies (S1); and calculating a frequency estimation of a virtual wideband navigation signal constructed based on the first navigation signal and the second navigation signal (S2), wherein the virtual wideband navigation signal is an asymmetric BOC-like navigation signal having a virtual carrier and a virtual sub-carrier. With the joint receiver and joint receiving method, not only power gain but also bandwidth gain can be obtained, and the ranging precision can be significantly improved.

Abstract: A receiver and a receiving method for receiving wideband binary-offset-carrier modulated signals. The receiver includes a tracking apparatus which includes an upper sideband processor operable to generate upper sideband correlations through correlating a local upper sideband replica against a received navigation signal, a lower sideband processor operable to generate lower sideband correlations through correlating a local lower sideband replica against the received navigation signal, and an estimator operable to determine a delay estimate based on the upper sideband correlations and the lower sideband correlations.

Abstract: A receiver and a receiving method for receiving wideband binary-offset-carrier modulated signals. The receiver includes a tracking apparatus which includes an upper sideband processor operable to generate upper sideband correlations through correlating a local upper sideband replica against a received navigation signal, a lower sideband processor operable to generate lower sideband correlations through correlating a local lower sideband replica against the received navigation signal, and an estimator operable to determine a delay estimate based on the upper sideband correlations and the lower sideband correlations.