Contents
2021
Volume: 42 Issue 6
9 Article(s)
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Research on Minority Carrier Lifetime Measurements of HgCdTe Thin Film
Wei-lin SHE, Chen SHEN, Qian LI, Ming LIU, Da LI, and Jing-xia SHI
The minority carrier lifetime of the mercury cadmium telluride (HgCdTe) material is an important parameter that affects the performance of the HgCdTe infrared detector. Microwave photoconductivity decay (-PCD) and microwave detected photoconductivity (MDP) methods are used to study the minority carrier lifetime of HgCdThe minority carrier lifetime of the mercury cadmium telluride (HgCdTe) material is an important parameter that affects the performance of the HgCdTe infrared detector. Microwave photoconductivity decay (-PCD) and microwave detected photoconductivity (MDP) methods are used to study the minority carrier lifetime of HgCdTe thin films. The results show that with the increase of laser power, the minority carrier lifetime of the sample decreases; due to the change of the carrier recombination mechanism, the minority carrier lifetime of the HgCdTe thin film increases first and then decreases with the increase of temperature. The distribution and uniformity of the carrier concentration in different regions of the sample can be obtained through the minority carrier lifetime distribution of the HgCdTe thin film. For HgCdTe thin film materials, the surface distributions of the above two test results are similar..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 1 (2021)
Dual-Channel Pyroelectric Infrared Gas Detector Based on PMN-PT Single Crystals
Jing ZHAO, Rong-feng ZHU, Meng-yuan ZHANG, Pei-gui FENG, Jian-wei CHEN, Jie JIAO, and Hao-su LUO
The relaxor-based manganese iron doped lead magnesium niobate/lead titanate (Mn∶Pb(Mg1/3-Nb2/3)O3-PbTiO3, Mn∶PMN-PT) ferroelectric single crystal has a high light transmittance in the near/mid-infrared band. The pyroelectric infrared detecting element was prepared by depositing an infrared absorption layer with broad sThe relaxor-based manganese iron doped lead magnesium niobate/lead titanate (Mn∶Pb(Mg1/3-Nb2/3)O3-PbTiO3, Mn∶PMN-PT) ferroelectric single crystal has a high light transmittance in the near/mid-infrared band. The pyroelectric infrared detecting element was prepared by depositing an infrared absorption layer with broad spectrum and flat absorption characteristics on its surface. The temperature difference and pyroelectric current change with frequency caused by the absorption of infrared radiation were simulated. The response characteristics and influencing factors of the voltage mode pyroelectric detector were discussed. Furthermore, a dual-channel compensated pyroelectric infrared detector based on Mn∶PMN-PT single crystal was prepared. The frequency response results obtained in the experiment are in good agreement with the simulation, and are suitable for gas detection based on the principle of non-dispersive infrared (NDIR)..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 7 (2021)
Structure Design of Cold Head for Ultra-Long Linear HgCdTe Detector Assembly
Wei LIU, Dong-liang ZHANG, Jie YAN, and Lei ZHANG
With the increasing space applications of large-scale linear detectors, the application requirements for ultra-long linear splicing detectors that can perform infrared scanning detection and capture targets with large range and high resolution are becoming more and more extensive. The large scale and geometric dimensioWith the increasing space applications of large-scale linear detectors, the application requirements for ultra-long linear splicing detectors that can perform infrared scanning detection and capture targets with large range and high resolution are becoming more and more extensive. The large scale and geometric dimensions of the HgCdTe infrared detector assembly with ultra-long linear arrays have caused the problem of low-temperature thermal mismatch of the cold head structure of the detector to be magnified. In order to obtain the cold head structure that can meet the low temperature reliability and strict imaging requirements, the research on the optimization method of the relevant cold head structure design and the experimental verification work of obtaining the actual object have been carried out. The experimental verification work has proved that the structural design optimization method in this study is applicable for the complex design of large-size cold head structure..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 12 (2021)
Optimal Design of Cold Box Structure of Large Scale Infrared Detectors
Zhi-kai FU, Zhi-hao FANG, Lei ZHANG, Qing WU, and Cheng-gang WANG
Aiming at the packaging requirements of large scale infrared detectors, the design methods and characteristics of cold box packaging structure are introduced in this paper. According to the use and demand of different types of large scale infrared detector assemblies, their packaging structure, weight, thermal load andAiming at the packaging requirements of large scale infrared detectors, the design methods and characteristics of cold box packaging structure are introduced in this paper. According to the use and demand of different types of large scale infrared detector assemblies, their packaging structure, weight, thermal load and reliability are analyzed and studied, and the packaging structure of large scale infrared detector assembly is optimized. Lightweight and low power consumption are taken as the design idea, and the packaging structure is optimized by the finite element simulation tool to meet the design requirements..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 19 (2021)
Influences of Bonding Parameters of Wedge Welding and Gold Ball on Bonding Tension
Yu-hui YUAN, Jie LIU, and Zhi-kai FU
The influences of pressure, power and time on the welding quality of the first joint of ultrasonic wedge welding and thermosonic bonding are studied based on practical application. The welding quality is determined according to the tension values measured by the tension tester, and the technological parameters satisfyiThe influences of pressure, power and time on the welding quality of the first joint of ultrasonic wedge welding and thermosonic bonding are studied based on practical application. The welding quality is determined according to the tension values measured by the tension tester, and the technological parameters satisfying the quality requirements of wedge and ball welding of detector chips are given. The overall welding quality is improved as well. In addition, two reinforcing methods after thermosonic bonding are studied, and the effects of the two methods are compared..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 24 (2021)
Ship Detection Method Based on Sea-Sky Line Extraction and Mixed Gray Difference
Ming-jing HUANG, Xue-mei WANG, Yuan JIAN, Wei-jie MENG, and Meng-meng MA
In order to quickly and accurately detect ship targets in long-range horizontal observation under sea-sky background, a ship detection method based on the sea-sky line extraction and mixed gray difference is proposed in this paper. Firstly, the image is divided into sky, sea-sky line and sea surface by the edge detectiIn order to quickly and accurately detect ship targets in long-range horizontal observation under sea-sky background, a ship detection method based on the sea-sky line extraction and mixed gray difference is proposed in this paper. Firstly, the image is divided into sky, sea-sky line and sea surface by the edge detection algorithm. The linear fitting method is adopted on the connection points of sea and sky to determine the parameters of sea-sky line. Then the sea-sky line area is extracted as the target area of interest, and the interferences such as sea clutter and noise are removed. The mixed gray difference horizontal and vertical projection are used to locate the target. Finally, the statistical value of the projection curve is analyzed to obtain the coordinates and size of the target. The experimental results show that this method can effectively detect ship targets in long-range horizontal observation under sea-sky background，and it is simple in calculation and fast in processing speed. So it can meet the real-time processing requirements of ship target detection..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 29 (2021)
Spatiotemporal Analysis of Land Cover Change Based on Local Climate Zones
Xuan XIE, Chao-min CHEN, Yun DU, and Ba-gan HASI
The demonstration zone of green and integrated ecological development of the Yangtze River Delta is located at the junction of Jiangsu Province, Zhejiang Province and Shanghai City, which plays an important role in the integration process of the Yangtze River Delta. In order to explore the land cover change and its driThe demonstration zone of green and integrated ecological development of the Yangtze River Delta is located at the junction of Jiangsu Province, Zhejiang Province and Shanghai City, which plays an important role in the integration process of the Yangtze River Delta. In order to explore the land cover change and its driving forces in the demonstration area since 2008, the local climate zone classification system and random forest classification method are adopted. Based on Landsat-5 TM optical images and dual polarization PALSAR data in 2008，the land cover of the demonstration area in 2008 is classified. Sentinel-2 MSI multispectral optical images and dual polarization PALSAR-2 data are used to classify the land cover of the demonstration area in 2020.The results show that from 2008 to 2020, the construction land area of the demonstration area increases significantly. Among them, the increase of open high-rise buildings is the most obvious, from 12.23 km2 in 2008 to 361.26 km2 in 2020.The area of low plants decreases greatly, from 535.92 km2 in 2008 to 197.26 km2 in 2020. Bush, scrub, and dense trees have also been reduced. The main driving factors of land cover change are urban expansion, shanty town reconstruction, population growth and industrial structure optimization. A reference for the study of land cover change in suburban areas in the process of urbanization is provided in this paper. In addition, a decision-making basis for promoting the construction of the demonstration zone of green and integrated ecological development of the Yangtze River Delta and the integration of Yangtze River Delta is provided..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 34 (2021)
Research on the Therapeutic Effect Evaluation of Gout Based on Infrared Thermography
Rui-yu YANG, Peng LI, Wei-yu WANG, FAN-Ping , and Jing-jin WU
Whether Infrared Thermography (IRT) can be used as one of the methods to evaluate the therapeutic effect of Gout is discussed. A multicenter, randomized, controlled trial design is adopted, and 60 gout patients with dampness heat accumulation syndrome are selected. Then they are divided into experimental group and contWhether Infrared Thermography (IRT) can be used as one of the methods to evaluate the therapeutic effect of Gout is discussed. A multicenter, randomized, controlled trial design is adopted, and 60 gout patients with dampness heat accumulation syndrome are selected. Then they are divided into experimental group and control group (30 cases in each group). The experimental group is given Zhuye Shigao Decoction granules orally, 1 bag/time, 3 times a day; the control group is given celecoxib capsule orally, 200 mg/time, once a day. Both groups take 7 days as a course of treatment. After the course of treatment, the changes of UA, CRP and infrared calorific values before and after the treatment of the two groups are observed. The results show that the CRP and infrared calorific value of both groups are improved(P<0.01).IRT is of great significance in evaluating the therapeutic effect of gout.参考文献<参考文献原文>曾小峰， 陈耀龙. 2016中国痛风诊疗指南[J]. 中华内科杂志， 2016， 55(11): 892-899..
- Publication Date: Jun. 01, 2021
- Vol. 42 Issue 6 45 (2021)
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