Abstract:To meet the further requirements of using ZnS thin films in the field of optical films, ZnS thin films were grown on GaAs substrates at 130 ℃ by using DEZn and H2S as reaction sources on the basis of Atomic Layer Deposition (ALD). The surface morphology and interfacial properties of the samples were analyzed by Scanning Electron Microscopy (SEM). The structural properties of the thin films were analyzed by X-ray Diffractometer(XRD) and the chemical compositions of the thin films were analyzed by X-ray Photoelectron Spectroscopy (XPS). The effects of thickness on the structure and morphology of the thin films were studied. The results showed that the ZnS thin films obtained were polycrystalline. Their thickness increased linearly with the number of cycles at a rate of 1.45 ?/cycle. The XPS analysis of the thin films baked at 75 ℃ for 48 h gave the ratio of Zn/S 1.07:1, which indicated that the residual H2S in the films was removed after baking. The thinner films grown in less time had better surface flatness and denser structure.

Abstract:The microtopography of homoepitaxial and Al-doped thin films grown on InSb (001) substrates and (001) misoriented by 2°(111) B substrates by Molecular Beam Epitaxy (MBE) was studied by Atomic Force Microscopy (AFM). The differences of the growing modes of homoepitaxial films on different substrates were compared. The crosshatch introduced after Al was added into InSb films was observed and its cause was analyzed. The research showed that the use of misoriented substrates was more favorable to the reduction of surface defects of InSb films grown by MBE.

Abstract:A low noise real-time imaging data acquisition system based on a 512×8 dual band TDI IRFPA is designed. According to the characteristics of internal circuits and output analog signals, a low noise collection circuit composed of bias voltage, drive circuit, A/D conversion circuit and digital signal processing module etc is designed. It is found in the noise test that at the room temperature of 26 ℃, the noise of the circuit is 0.02 mV to 0.18 mV. For the integration time of 300 μs, the noise voltage of each shortwave infrared detector element and that of each mid-wave infrared detector element are 2.5 mV to 4.5 mV and 8 mV to 10 mV respectively. Their signal-to noise ratios are 52 dB to 57 dB and 43 dB to 48 dB respectively. The test results show that the system has good noise characteristics and can meet the requirements of practical engineering application.

Abstract:A simulation method of infrared (IR) detection of midcourse ballistic targets by spaceborne early warning systems is proposed. The IR radiation characteristics of midcourse targets are studied by using the infrared module of Satellite Tool Kit/Electro-Optical Infrared Sensor (STK/EOIR). First, the simulation method of dynamic IR radiation characteristics of midcourse ballistic targets based on STK/EOIR is proposed. The calculation model of IR radiation of EOIR targets and the receiving model of the sensor are analyzed. Then, the simulation results of IR irradiation of a typical target in mid-infrared waveband, mid and long infrared waveband and long infrared waveband are given. Finally, the influences of observation angle and observation range on the target IR irradiation received by spaceborne staring sensors are compared. The simulation results show that the IR radiation intensity of midcourse ballistic targets can meet the detection sensitivity requirements of spaceborne staring sensors.

Abstract:Traditional simulation technologies are limited by algorithm complexity, computing power and interface bottlenecks. To solve this problem, a system which implements real-time dynamic infrared scene simulation in real images on the basis of augmented reality is designed. Firstly, 3DS MAX is used to establish a virtual target model. The geometric consistency transformation and infrared radiation consistency transformation are carried out for the virtual target model. Then, SURF-ORB feature matching is used to track the motion of the detector. Finally, the virtual target is fused with the real scene through raster rending. Thus, the design of the dynamic infrared scene simulation system based on augmented reality is completed. The experimental results show that high frame rate and high realism infrared simulation images can be obtained by this system. Its scalability is very strong.

Abstract:To solve the problem that it is difficult to give early fire-warning for forest, the feasibility of using a single element mercury cadmium telluride (MCT) infrared detector in the field of forest fire prevention is analyzed. By utilizing the characteristics of high sensitivity, low power consumption and low cost of single element MCT infrared detectors, an omnidirectional scanning forest fire early warning system based on a single element MCT detector is designed. The system is powered by solar energy and wind energy. Its infrared detector is used to implement the collection, amplification, processing and imaging of the mid-infrared radiation signals of forest fire. The collected signals are sent to the computer monitoring center through RS485 and GPRS. When a fire occurs, the system can send the fire early warning information to firefighters stably in time under various geographic and climate conditions.

Abstract:When a space vehicle is flying at ultra-high speed in the atmosphere, a plasma sheath may form around it due to aerodynamic heating or ablation. This will affect the communication characteristics of the space vehicle. Further, it will result in serious communication disruption and hence threaten the safety of the space vehicle. The new generation of space vehicles of our country will fly in the atmosphere for longer time at higher speed. Moreover, because of their complex trajectory, real-time communication and control are needed. Therefore, the problem of communication disruption should be solved thoroughly. The possibility of using the methods such as distribution optimization of antenna location and ground telemetry equipment, millimeter-wave and terahertz wave communication, external magnetic field and laser communication to solve blackout and the problems to be faced are studied.