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In the intersatellite laser communication system, the circumferential optical tracking structure has the advantages of small size and simple structure, which can be widely used. However, due to the coupling relationship between the azimuth axis and the pitching axis in the tracking of the target laser signal, and the disturbance caused by the electric machine, the satellite is used to get in and out of the earth. The vibration, which affects the tracking precision. In order to improve the tracking accuracy of the system, the matrix optical method is adopted to establish the propagation matrix of the light in the circumferential laser communication terminal, and the rough tracking algorithm based on the target light angle and the attitude information of the communication terminal is derived. Then the BP neural network is used to set the PID control on the basis of the precise motor model. Methods, the control model of communication terminal is established. Finally, the rough tracking control model is built in the Matlab-Simulink environment. The experiment validates the necessity of establishing the tracking algorithm model, and obtains better dynamic tracking error to meet the high precision rough tracking requirement of the inter satellite laser communication.

During ripening, peach fruits (Prunus persica L. Batsch) rapidly progress to the senescent stage, resulting in a brief shelf life. Abscisic acid (ABA) plays an important role in regulating the ripening process, both in climacteric and non-climacteric fruits. A key enzyme for ABA biosynthesis in higher plants is 9-cis-epoxycarotenoid dioxygenase (NCED). In this study, two NCED isozymes, PpNCED1 and PpNCED5, were identified in peach fruits. While both NCED genes had similar transcriptional patterns (up-regulation) at the beginning of peach ripening, PpNCED5 showed a consistently lower expression level than PpNCED1. During the post-harvest stage, gene expression of PpNCED1 declined, while PpNCED5 expression increased relative to PpNCED1 expression. Considering the dynamic process of ABA accumulation during fruit ripening and senescence in peach, this study indicates that both NCED genes cooperatively control ABA biosynthesis in peach fruits. Moreover, spatio-temporal expression and transcriptional response to hormone and abiotic stress suggested that there is functional divergence between PpNCED1 and PpNCED5 genes in peach. A carotenoid-rich callus system was used to verify the function of PpNCED1 and PpNCED5. In the transgenic callus system, both PpNCED1 and PpNCED5 isozymes promoted ABA biosynthesis, which likely accelerated cell senescence through activating ROS signals. The results from this study provide evidence supporting an ABA biosynthetic regulation process via the two NCED genes in peach fruit, and suggest a mechanism of ABA-induced fruit ripening and senescence.

In order to reduce the servo control error, Solidworks, ADAMS and MATLAB are adopted to jointly simulate the electromechanical control system of the system. Based on Solidworks, the physical model of optical end machine is built in combination. The system dynamics model is established in ADAMS and the servo control model is established in MATLAB. Through the analysis of the simulation results of the system model, it is shown that the system has fast response speed, small overshoot, better apparent axial direction accuracy than 5″, better steady state tracking accuracy than 10″, and meets the requirements of system indicators. Simulation analysis establishes the feasibility of the system. In addition, the servo control simulation parameters provide a reliable reference for the control and debugging of the actual system and improve the efficiency of equipment research and development.

In order to verify the feasibility of in-vehicle laser communication technology, the application scenarios and basic principles of vehicle-mounted laser communication system are researched. According to the index requirements, the overall design of the system is completed and field experiments are carried out. Under different atmospheric visibility and different communication distance Communication error rate, to evaluate the communication quality, and to detect and analyze the mast sloshing. Finally, the vehicle laser communication prototype was completed to achieve near-surface laser communication within 15km and 100mbps. The feasibility and design of vehicle-mounted laser communication were verified The correctness of the scheme and provide the basis for the improvement of the prototype of the principle in the future.