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With continuous development of the key technologies of star sensor,the precision of star simulator have been to be further improved,for it directly affects the accuracy of star sensor laboratory calibration.For improving the accur...
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With continuous development of the key technologies of star sensor,the precision of star simulator have been to be further improved,for it directly affects the accuracy of star sensor laboratory calibration.For improving the accuracy level of the star simulator,a theoretical accuracy analysis model need to be proposed. According the ideal imaging model of star simulator,the theoretical accuracy analysis model can be established.Based on theoretically analyzing the theoretical accuracy analysis model we can get that the starlight emergent angle deviation is primarily affected by star position deviation,main point position deviation,focal length deviation,distortion deviation and object plane tilt deviation.Based on the above affecting factors,a comprehensive deviation model can be established. According to the model,the formula of each factors deviation model separately and the comprehensive deviation model can be summarized and concluded out.By analyzing the properties of each factors deviation model and the comprehensive deviation model formula,concluding the characteristics of each factors respectively and the weight relationship among them.According the result of analysis of the comprehensive deviation model,a reasonable designing indexes can be given by considering the star simulator optical system requirements and the precision of machining and adjustment.So,starlight emergence angle error analysis of star simulator is very significant to guide the direction of determining and demonstrating the index of star simulator,analyzing and compensating the error of star simulator for improving the accuracy of star simulator and establishing a theoretical basis for further improving the starlight angle precision of the star simulator can effectively solve the problem.
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摘要 :
With continuous development of the key technologies of star sensor,the precision of star simulator have been to be further improved,for it directly affects the accuracy of star sensor laboratory calibration.For improving the accur...
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With continuous development of the key technologies of star sensor,the precision of star simulator have been to be further improved,for it directly affects the accuracy of star sensor laboratory calibration.For improving the accuracy level of the star simulator,a theoretical accuracy analysis model need to be proposed. According the ideal imaging model of star simulator,the theoretical accuracy analysis model can be established.Based on theoretically analyzing the theoretical accuracy analysis model we can get that the starlight emergent angle deviation is primarily affected by star position deviation,main point position deviation,focal length deviation,distortion deviation and object plane tilt deviation.Based on the above affecting factors,a comprehensive deviation model can be established. According to the model,the formula of each factors deviation model separately and the comprehensive deviation model can be summarized and concluded out.By analyzing the properties of each factors deviation model and the comprehensive deviation model formula,concluding the characteristics of each factors respectively and the weight relationship among them.According the result of analysis of the comprehensive deviation model,a reasonable designing indexes can be given by considering the star simulator optical system requirements and the precision of machining and adjustment.So,starlight emergence angle error analysis of star simulator is very significant to guide the direction of determining and demonstrating the index of star simulator,analyzing and compensating the error of star simulator for improving the accuracy of star simulator and establishing a theoretical basis for further improving the starlight angle precision of the star simulator can effectively solve the problem.
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Hydrogen atoms adsorption and diffusion properties on clean and vacancy defective Mg (0001) surface have been investigated systematically by using a first-principles calculations method based on the density functional theory. The ...
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Hydrogen atoms adsorption and diffusion properties on clean and vacancy defective Mg (0001) surface have been investigated systematically by using a first-principles calculations method based on the density functional theory. The calculation results of adsorption energy and diffusion energy barrier show that hydrogen atom is apt to be adsorbed at fcc and hep sites on clean Mg (0001) surface, and fcc adsorption site is found to be more preferred. The highest diffusion energy barrier is estimated as 0.6784eV for H atom penetrating into clean Mg (0001) surface. Comparatively, Mg atom vacancy on Mg (0001) surface not only enhances the chemisorption interaction between H and Mg surface, but also benefits H atom diffusion in Mg bulk with relatively more diffusion paths compared with that of clean surface. Besides, H atom is found to occupy mostly the tetrahedral interstice when it diffuses into the Mg bulk. Further analysis of the density of states (DOS) shows that the system for H atom to be adsorbed at fcc site has a lower density of states (DOS) value (N (EF)) at Fermi level and more bonding electrons at the energy range blow the Fermi level of H/Mg (0001)clean system as compared with that for H atom to be adsorbed at hcp site. On the other hand, the enhanced chemisorption interaction between H and defective surface should be attributed to the fact that the electronic structures of Mg (0001) surface are modified by Mg atom vacancy, and the bonding electrons of the uppermost layer Mg atoms are transferred from low energy range to Fermi level, which is in favor of improving the surface activity of Mg (0001) surface.
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KATECH(Korea Automotive Technology Institute) has developed a virtual reality based testbed facility named KAAS(KATECH Advanced Automotive Simulator) as a test and development environment for Telematics and ITS. The KAAS is an int...
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KATECH(Korea Automotive Technology Institute) has developed a virtual reality based testbed facility named KAAS(KATECH Advanced Automotive Simulator) as a test and development environment for Telematics and ITS. The KAAS is an integrated system of a large scale driving simulator, four different HILS(Hardware-In-the-Loop Simulation) systems which generates vehicle state signals for the target device, human behavior/reaction analysis devices, a CDMA wireless communication simulation system, a GPS RF signal generation device, and several other devices. Using the KAAS system, GPS based car navigation devices/software, location based service using CDMA wireless communication, driver workload and disturbance, interaction time for in-vehicle display systems, in-vehicle network performance and many other functions are evaluated under in-door test environment. Using the HILS systems, the target device can have an integrated test with car even before the prototype is completed. The unfinished module is replaced by simulation software model running in the HILS system providing the necessary signals.
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The paper presents a numerical simulation of the fire-induced gas flow in a corridor, which contains a heat source on the floor and a doorway opening at its one end. The buoyancy-modified k-s model is utilized to simulate the gas ...
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The paper presents a numerical simulation of the fire-induced gas flow in a corridor, which contains a heat source on the floor and a doorway opening at its one end. The buoyancy-modified k-s model is utilized to simulate the gas turbulence. The gas pressure is specified at the doorway boundary. The distributions of gas velocity, temperature and turbulence properties are obtained under different conditions. The results exhibit that the flow is featured as the stratification of the gas temperature distribution and the incoming flow from the environment to the corridor. The effects of heat release rate on the fire-induced gas flow in the corridor are investigated.
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Aiming at the problem of peak load increase in distribution network brought unorderly charging of large-scale EVs, a multi-objective optimal dispatch method for cluster electric vehicles connected to distribution network is put fo...
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Aiming at the problem of peak load increase in distribution network brought unorderly charging of large-scale EVs, a multi-objective optimal dispatch method for cluster electric vehicles connected to distribution network is put forward. By analyzing actual investigation data of electric vehicles in urban traffic report, the charging load needs of large-scale EVs is analyzed basing Monte Carlo simulation approach, and the optimization goal is optimized by optimizing the operating cost of distribution network. Considering the charging needs of EVs and the operation constraints, the optimal scheduling model of large-scale electric vehicles is constructed, and the multi-objective optimization model is solved by non-autonomous genetic algorithm (NSGA-Ⅱ) with elite strategy. The proposed model and method can efficiently suppress the voltage fluctuation caused by the large-scale EV access to the distribution network,while ensuring the economic operation of the system and ensure the power quality of the system.
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In high-speed banknote sorting system, to real-time deal with massive data and complex algorithm is required. This paper proposes an embedded processing system, which realizing the high-speed image acquisition and real-time proces...
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In high-speed banknote sorting system, to real-time deal with massive data and complex algorithm is required. This paper proposes an embedded processing system, which realizing the high-speed image acquisition and real-time processing of banknote image. The system is a customized and flexible architecture consisting of one large scale FPGA and four high performance DSP chips. The five processors have good communication with each other by RapidIO BUS. After evaluating the system-calculating overhead, the data throughput, and the hardware characteristics, we presents the whole processing program systematically running in FPGA and DSPs. In order to make full use of the advantage of FPGA highly parallelism and DSP deeply pipeline, the FPGA is designed for running parallel algorithms with large amount of calculation but low complexity of control flow, and the rest of algorithms are assigned to the four DSPs relatively. Finally, the whole program of image processing at the speed of 40 frames per second is realized on the embedded processing platform. The system has been successfully used in high-speed banknote sorting device, which has showed stable and reliable properties. And it also has excellent performance in processing ability with the verification of large scale operation.
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In high-speed banknote sorting system, to real-time deal with massive data and complex algorithm is required. This paper proposes an embedded processing system, which realizing the high-speed image acquisition and real-time proces...
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In high-speed banknote sorting system, to real-time deal with massive data and complex algorithm is required. This paper proposes an embedded processing system, which realizing the high-speed image acquisition and real-time processing of banknote image. The system is a customized and flexible architecture consisting of one large scale FPGA and four high performance DSP chips. The five processors have good communication with each other by RapidIO BUS. After evaluating the system-calculating overhead, the data throughput, and the hardware characteristics, we presents the whole processing program systematically running in FPGA and DSPs. In order to make full use of the advantage of FPGA highly parallelism and DSP deeply pipeline, the FPGA is designed for running parallel algorithms with large amount of calculation but low complexity of control flow, and the rest of algorithms are assigned to the four DSPs relatively. Finally, the whole program of image processing at the speed of 40 frames per second is realized on the embedded processing platform. The system has been successfully used in high-speed banknote sorting device, which has showed stable and reliable properties. And it also has excellent performance in processing ability with the verification of large scale operation.
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Production performance of the Du 163 pilot was evaluated from comprehensive analysis of material balance, heat utilization efficiency, displacement efficiency, and economics analysis. The study was conducted by means of material b...
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Production performance of the Du 163 pilot was evaluated from comprehensive analysis of material balance, heat utilization efficiency, displacement efficiency, and economics analysis. The study was conducted by means of material balance, analytical and numerical simulation methods. Results show that the fluid migrated outside the pilot boundaries during steamflooding. The heat efficiency was very low. Only 35percent of the injection heat was utilized to heat the reservoir. Displacement efficiency was low and the economics was very poor. If effluent (off pilot) oil is taken into consideration, the oil steam ratio of the pilot area will be 0.19, and its economic benefit are improved.
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The assembly behavior of the nonionic surfactant Triton X-100 at the water/oil interface was studied on the mesoscopic level using a dissipative particle dynamics simulation.We extended the calculation method for interracial tensi...
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The assembly behavior of the nonionic surfactant Triton X-100 at the water/oil interface was studied on the mesoscopic level using a dissipative particle dynamics simulation.We extended the calculation method for interracial tension from a binary water/oil system to a ternary system with surfactants.In particular,the simulated results of interfacial tension that were chosen for illustration are in excellent agreement with the experimental results.Additionally,we discuss the relationship between interfacial tension and interfacial density,which supports the synergistic theory of mixed surfactants.The microscopic information obtained from the simulated method will opens another door for the selection and application of surfactants in enhanced oil recovery.
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