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Ren Z.-B.,Harbin Institute of Technology | Ma C.,Harbin Institute of Technology | Jin C.-G.,Harbin Institute of Technology | Zhao H.-Y.,AVIC Jiangxi Hongdu Aviation Group Co.
Guangzi Xuebao/Acta Photonica Sinica | Year: 2014

A microlenses array beam expander system was design based on the infrared jamming technology with two jamming light paths. The microlenses array was fabricated by melting photoresist technology, the energy collection efficiency of the jamming simulation system was tested. The results show that the tested energy collection efficiencys of two jamming light paths are 27.3% and 26.9%, which are consistent with the design result 30.8%.This study verifies the application value of microlenses array as the beam expander element in the infrared jamming simulator and can provide references for the engineering research of infrared imaging simulation technology and infrared imaging target simulator with multiple jamming light paths.


Ren Z.,Harbin Institute of Technology | Ma C.,Harbin Institute of Technology | Jin C.,Harbin Institute of Technology | Zhang C.,AVIC Jiangxi Hongdu Aviation Group Co.
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2014

In order to achieve high resolution, remote sensing system in the geo-stationary orbit is usually equipped with large aperture optical system. However, the field of view of the optical system is usually very small. Scan imaging technology can be adopted to achieve larger detection range for a high-resolution remote sensing optical system in the geo-stationary orbit. Therefore, the image spots keep moving with the rotary movement of scan mirror, and image spot aliasing emerges in each CCD exposure time. Thus, the Modulation Transfer Function (MTF) of scan imaging optical system degrades. Dynamic optical transfer function method is adopted to study the imaging characteristics of continuous scan imaging optical system. The results show that in exposure time range of 0.5~1.5 ms, the rotation angle of scan mirror should be less than 7×10-6 degree to keep high MTF. Finally, a feasible drive method of the continuous scan mirror is given and the effect of driving instability on MTF is also analyzed. The results of this paper can provide references for further research and fabrication of continuous scan imaging optical systems.


Feng Y.,Nanchang University | Li Y.-L.,Nanchang University | Zhang H.,Nanchang University | Xu M.,AVIC Jiangxi Hongdu Aviation Group Co.
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2011

Embedded FBG sensors can detect the internal state of stresses, temperatures and many other factors as an alternative to the other sensors. Before being embedded into the metal structures, FBG sensors must be protected by some metal materials. The discrepancy exists between the stress values recorded by FBG and the actual stresses. This paper relates the discrepancy to the two parameters that are the stress transfer coefficient and the location function. For a special connecting layer, the bigger elastic modulus and the smaller thickness of the protective layer, the bigger the stress transfer coefficient. When the FBG is embedded on the right of the designated position, the location function gets big with the increase of the tilt angle. When it is on the left of the designated position, the location function gets small with the increase of the tilt angle.


Feng Y.,Nanchang University | Xu M.,AVIC Jiangxi Hongdu Aviation Group Co. | Li Y.-L.,Nanchang University | Zhang H.,Nanchang University | Yu Y.-X.,Nanchang University
Guangdianzi Jiguang/Journal of Optoelectronics Laser | Year: 2012

When fiber Bragg grating (FBG) sensors are used to measure stresses and strains, the influence of the ambient temperature on the FBG should be avoided or compensated. The temperature sensitivity of a FBG can be decreased by using an appropriate coating on the FBG. A novel Ni-ZrO 2 composite coated FBG sensor with a lower temperature sensitivity is developed in this study. Elemental distribution scan (EDS) tests show that the contents of Zr and Ni are 30.12 wt.% and 67.87 wt.%, respectively. Scanning electron microscope (SEM) tests show that the Ni-ZrO 2 composite coating covers the fiber well. Temperature sensing experiments were conducted by using two Ni-ZrO 2 coated FBGs in the temperature range of 30~90°C. The results show that the average temperature sensitivity coefficient decreases by 34.59% compared with the Ni-coated FBG, which indicates that the FBG with Ni-ZrO 2 composite coating has a lower temperature sensitivity.


Feng Y.,Nanchang University | Li Y.,Nanchang University | Xu M.,AVIC Jiangxi Hongdu Aviation Group Co. | Wang W.,Nanchang University
Chinese Journal of Sensors and Actuators | Year: 2012

The optical fiber Bragg grating sensor is sensitive to both strain and temperature. The metallized FBGs have much higher temperature sensitivity than the bare FBGs. The contraction and exothermic reaction take place during the consolidation process of the denture resin base materials. A measurement system manufactured using a bare FBG and a nickel coated FBG was designed to simultaneously measure the temperature and strain change of the room temperature-curing process of the denture base resin in this paper. The experimental data show the maximum temperature change occurred at the twenty-first minute during the room temperature-curing process of the denture base resin. The maximum temperature change(ΔT)and the strain(Δε)are 12.8°C and 2.61 με, respectively. The results of this study may be useful to the clinical treatments.


Wang Y.,Nanjing University of Aeronautics and Astronautics | Wang Y.,Science and Technology on Electro optic Control Laboratory | Han Z.,AVIC Jiangxi Hongdu Aviation Group Co. | Chen S.,Science and Technology on Electro optic Control Laboratory | And 2 more authors.
Nanjing Hangkong Hangtian Daxue Xuebao/Journal of Nanjing University of Aeronautics and Astronautics | Year: 2014

Threat evaluation is a time-sensitive, uncertain and dynamic process. In order to access a profound understanding, a detailed description of 18 threat cues essential in the assessment process is given firstly. And Gaussian function is used as fuzzy membership function to deal with data required. At the same time, Bayesian network structure is designed for complex threat factors. Then a two-stage evaluation structure based on the above description is proposed: Important information unknown about distant target is speculated based on the association rules and then average linear weighted method is used on the parameters to get the assessment results; Bayesian network is used when information is complete. Finally simulation results verify the validity and rationality of the model.


Wang Y.,Nanjing University of Aeronautics and Astronautics | Wang Y.,Science and Technology on Electro Optic Control Laboratory | Chen S.,Science and Technology on Electro Optic Control Laboratory | Han Z.,AVIC Jiangxi Hongdu Aviation Group Co. | And 2 more authors.
Transactions of Nanjing University of Aeronautics and Astronautics | Year: 2014

In order to improve weapon assignment (WA) accuracy in real scenario, an artificial neural network( ANN) model is built to calculate real-time weapon kill probabilities. Considering the WA characteristic, each input representing one assessment index should be normalized properly. Therefore, the modified WA model is oriented from constant value to dynamic computation. Then an improved invasive weed optimization algorithm is applied to solve the WA problem. During search process, local search is used to improve the initial population, and seed reproduction is redefined to guarantee the mutation from multipoint to single point. In addition, the idea of vaccination and immune selection in biology is added into optimization process. Finally, simulation results verify the model's rationality and effectiveness of the proposed algorithm. ©, 2015, Nanjing University of Aeronautics an Astronautics. All right reserved.

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