Abstract:Because of excellent infrared optical properties, infrared transmission crystal materials are widely used in both the military field and the civil field. The property requirements of infrared transmission crystal materials and their significance are presented in brief. By taking the excellent property as a precondition, the current research status of the infrared transmission crystal materials at home and abroad is presented. Finally, the trend of the infrared transmission crystal materials is forecasted.

Abstract:Infrared detection systems include the systems for detecting point targets and the thermal imaging systems for detecting extended source targets. As a system-level performance description parameter, the operating range can be used to characterize the quality of a detection process. The equation of the operating range for a detector depends on whether the source is a point one or an extended one. Besides, it also depends on whether the desired energy is a radiation energy form or a photon form. The operating range equations under different conditions are presented. The influence of system parameters, such as the F/# and diameter of optics and the field angle of a detector, on the operating range of both a search system and a thermal imaging system is discussed. Finally, the understanding and comprehension for the operating range of infrared detection systems are given.

Abstract:A detection imaging system for 128?128 two-color HgCdTe infrared focal plane arrays is designed. The system consists of a detector adapter module, a video analog signal conditioning module, an analog-to-digital converter module, a non-uniformity correction module and a digital image output module, etc. The imaging features and performance of the system are tested together with the optical system and the host computer image recording software. So far, the detection imaging system has been successfully used in animaging infrared guidance system.

Abstract:A practical security system for human body inspection was designed and manufactured. In this system, the newest quasi-optical technology and the active millimeter wave (MMW) scanning technology were used. The experimental result showed that the system had a resolution better than 10.2 mm in an operation mode at a frequency of 35 GHz (8.57 mm). It could inspect trace powder such as 0.5 g metal or nonmetal fixture and could complete the inspection over an area of 600 mm?1800 mm within 100 s, which had met the requirement for practical use. The inspection experiment showed that the system could be used in some special applications such as noble metal detection.

Abstract:High-energy lasers are widely used in the fields of science, industry and military. Because of the influence of atmosphere on the transmission of a laser, the investigation of far-field beam quality of a high-power laser is always a problem. To obtain the optical intensity distribution of a 1.4 kW pulsed TEA CO₂ laser at the distance of 500 m, a relative measurement method combined with absolute measurement is proposed. The measurement data are discussed and analyzed. The experimental result shows that the maximum power density on the target is 1.65 W/cm2 and the divergence angle in the cross direction is up to 0.96 mrad. The result is valuable to the optimization design of laser systems.

Abstract:The cadmium sulfide (CdS) semiconductor thin film for solar cells were prepared by using a chemical bath deposition method. The factors which had influence on film formation, film structure and its optical properties were tested and studied preliminary. The result showed that the pH value of the reaction solution and the annealing temperature were the main factors that had influence on film formation. In the experiment, the pH value was controlled in the range from 10.5 to 10.8 and the optimum annealing temperature was 400 ℃. In addition, by dropping some CdCl₂ solution and dripping it onto the surface of the film in annealing, the transmittance of the film in the region of visible light can be further improved.

Abstract:Rapid analysis of biomass fuel is of great importance to the energy utilization of agricultural and forestry waste. The models for predicting the moisture, ash, volatile matter, fixed carbon and calorific value of three kinds of agricultural and forestry waste such as pine wood, cedar wood and cotton stalk are established by using a visible and near-infrared spectroscopy. All of these models have a determination coefficient greater than 0.88 after cross validation. When the artificial neural network (ANN) modeling with several latent variables is used, the models have the average determination coefficient of up to 0.95 for moisture. The result shows that the visible and near-infrared spectroscopy combined with chemometrics can be used to replace the traditional analysis methods in industry completely and can provide a new method for the rapid detection of the biomass fuel properties of agricultural and forestry waste.

Abstract:A near-infrared spectral analysis model is established by using a multi-model method. The model can be used to rapidly determine the lignin content in populus euramericana. The correlation coefficient between the predicted value and the experimental value is 0.9702. The mean relative error of the prediction is 0.0100. The goodness of the fit model is 0.9126. Compared with the determination model established by using the partial least squares (PLS) method, the prediction of this model is better.