Journals >Journal of Atmospheric and Environmental Optics
Contents
2019
Volume: 14 Issue 4
11 Article(s)
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Domesticin-situ Analyzer of Greenhouse Gases with Fourier Transform Infrared Spectroscopy and its Primary Application in Atmospheric Background Observation
Xiaochun ZHANG, Qingli SONG, Yong CAO, Peng WANG, Dajiang YU, Mian WAMG, and Min WEN
Fourier transform infrared spectroscopy (FTIR) technique is widely used in the field of atmospheric environment observation. A in-situ FTIR analyzer system based on the combination of the technology of Fourier infrared spectrum and White type multiple reflection cell was used to measure the multi-species of CH4, CO, COFourier transform infrared spectroscopy (FTIR) technique is widely used in the field of atmospheric environment observation. A in-situ FTIR analyzer system based on the combination of the technology of Fourier infrared spectrum and White type multiple reflection cell was used to measure the multi-species of CH4, CO, CO2 and N2O in the field of Longfengshan background GAW station, Heilongjiang, China, and its comparation with the CRDS and GC system was also carried out concurrently. The results show that, (1) the detection limit of FTIR principle prototype is a higher than that of design, which can satisfy the in-situ observation of high concentration of greenhouse gas emissions. However, there was still a certain gap between the syetem and the requirement of the WMO-GAW atmospheric background observation, which means that the domestic FTIR principle prototype has room for improvement in the detection ability (such as light energy attenuation, efficient optical path, the wavelength calibration and measurement chamber, etc.), the analysis precision, uncertainty, and the system stability, etc. (2) By comparison with CRDS and GC system, it was shown that there were a higher agreement on the trend consistency and correlation of CH4 and CO, although the trend consistency of CO2 and N2O was not very ideal, which indicates that the performance of the analyzer system might be relative to the observation system, such as original principle, analysis and detect technology, ambient sample processing, data processing and so on..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 279 (2019)
[in Chinese]
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 1 (2019)
Development of Spectral Radiance Measurement System for Sky Background
Shunping CHEN, Fengying SUN, Wenqing XU, and Heli WEI
To meet the requirement of real-time spectral measurements and feature extraction of sky background radiance, a measuring instrument for spectral radiance of sky background was developed based on fiber optical spectrometer, to acquire spectrum from the wavelength of 340 nm to 1030 nm, which could both operate at fixed To meet the requirement of real-time spectral measurements and feature extraction of sky background radiance, a measuring instrument for spectral radiance of sky background was developed based on fiber optical spectrometer, to acquire spectrum from the wavelength of 340 nm to 1030 nm, which could both operate at fixed direction mode and whole sky scanning mode. Besides the overall structure, the details of optical component, rotating system, sun tracing module, temperature maintain system, software design, working process and calibration method were also presented. The calibrated test results were analyzed to prove the instruments’ reliability, and shows that it provided a way for real-time spectral measurements of sky background radiance..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 241 (2019)
Analysis of Characteristics of Onshore Turbine Wakein Xinjiang
Xiaoqing YU, and Songhua WU
The wind turbine wake can reduce the wind energy conversion efficiency, increase mechanical stress damage and reduce the life span of wind turbine. In order to study the characteristics of turbine wake in Xinjiang, China, the observation of wind based on pulse Doppler lidar was conducted in November 2015. The characterThe wind turbine wake can reduce the wind energy conversion efficiency, increase mechanical stress damage and reduce the life span of wind turbine. In order to study the characteristics of turbine wake in Xinjiang, China, the observation of wind based on pulse Doppler lidar was conducted in November 2015. The characteristics of wind turbine wake in Xinjiang were obtained, including the velocity deficit, wake width, wake length and average value of wake, variation of wake with time and relationship between wake and wind speed. The final results show that the velocity deficit, the wake width and the wake length are related to ambient wind velocity and wind turbulence intensity..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 250 (2019)
Wind Field Simulation of Capital Airport Based on Lidar Data
Lei LIU, Songhua WU, and Hongwei ZHANG
The low-level wind effect refers to the phenomenon that the airport structure or other artificial structures located near the runway cause significant disturbance to the airflow under certain wind conditions. This effect is likely to cause turbulence or even wind shear, and bring difficulties to the aircrafts’ takeoff The low-level wind effect refers to the phenomenon that the airport structure or other artificial structures located near the runway cause significant disturbance to the airflow under certain wind conditions. This effect is likely to cause turbulence or even wind shear, and bring difficulties to the aircrafts’ takeoff and landing. The computational fluid dynamics(CFD) method was adopted to simulate the wind field at Capital Airport, Beijing, China. To overcome the limitation of CFD in the setting of input wind speed, high-precision and high-resolution data measured by lidar were introduced into CFD as input condition to investigate the influence of buildings and artificial structures on wind speed at Capital Airport. The simulation results show that when the wind speed of 11～15 m/s under northwest wind condition was applied, the air flow near east runway was influenced significantly. The same situation happened in the west runway and the middle runway under the south wind condition with the same wind speed..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 259 (2019)
Research of Enrichment System for VOCs in Ambient Air Based on Adsorbent Tube Sampling/Cold Trap Focusing Method
Wei LIU, Tianshu ZHANG, Fan LU, Yongchao LIU, Peisong ZHOU, and Rongchun HU
An enrichment system for volatile organic compounds (VOCs) in ambient air based on adsorbent tube sampling/cold trap focusing method was developed. The VOCs in ambient air are sampled firstly by the adsorbent tube, and then focused on the cold trap. After the cold trap thermal analysis, the VOCs enter the GC-FID systemAn enrichment system for volatile organic compounds (VOCs) in ambient air based on adsorbent tube sampling/cold trap focusing method was developed. The VOCs in ambient air are sampled firstly by the adsorbent tube, and then focused on the cold trap. After the cold trap thermal analysis, the VOCs enter the GC-FID system with the high purity carrier gas. The performance of the system was measured by using standard gases(benzene, methylbenzene, ethylbenzene). The experimental results show that the cold trap designed by this system has a focusing efficiency of more than 90% for VOCs (benzene series), and relative standard deviation of standard samples is less than 3%, and the linear correlation coefficient is greater than 0.99. The system is stable in operation, and satisfies the demand for enrichment of VOCs in the ambient air..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 266 (2019)
Design and Realization of VOCs Peak Data Processing Method in Atmospheric Environment
Yongchao LIU, Fan LU, Wei LIU, and Rongchun HU
A data processing method is designed to deal with the severe baseline drift and complex peak shape of the volatile organic compounds (VOCs) chromatography. Methods of moving average and wavelet transform are applied to deal with the high frequency noise and baseline drift, which ensure the accuracy of peak recognition A data processing method is designed to deal with the severe baseline drift and complex peak shape of the volatile organic compounds (VOCs) chromatography. Methods of moving average and wavelet transform are applied to deal with the high frequency noise and baseline drift, which ensure the accuracy of peak recognition and area calculation. The combination of first order and two order derivative method is used to identify the chromatographic peaks. The Gauss curve fitting method is used to calculate the peak area, which improves the calculation accuracy of peak area. The experimental results show that the algorithm is very fast and the effect of the denoising and baseline correction are obvious. The algorithm can accurately identify overlapping peaks, acromion peaks and can get high precision of peak area calculation, which are able to meet the requirements of VOCs data processing in ambient air..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 272 (2019)
Development and Validation of Proton Transfer Reaction Time of Flight Mass Spectrometer
Qu LIANG, Yating ZHANG, Qiangling ZHANG, Xue ZOU, Meiling CHEN, Hongmei WANG, Chaoqun HUANG, Chengyin SHEN, and Yannan CHU
The construction and the performance of the newly developed proton transfer reaction time of flight mass spectrometer (PTR-TOFMS) are reported. Firstly, the threshold voltage of the discriminator on data acquisition board was optimized. The results show that when the threshold voltage is 0.33 V, the intensity ratio of The construction and the performance of the newly developed proton transfer reaction time of flight mass spectrometer (PTR-TOFMS) are reported. Firstly, the threshold voltage of the discriminator on data acquisition board was optimized. The results show that when the threshold voltage is 0.33 V, the intensity ratio of H316O+ (m/z 19) and H318O+ (m/z 21) is about 500:1. Then the relationship between the distribution of water clusters ion H3O+ (H2O)n=0,1,2,3 and the reduced electric field in drift tube was studied. The results show that when reduced-field (E/N) is 139 Td (1 Td=10－17 Vcm2), the water cluster ions are well suppressed, and the purity of the ion H3O+ is more than 99%. The resolutions at different m/z were also investigated. The results show that the best resolution is at m/z=124 with RMAX=2653. The performance of the PTR-TOFMS instrument was tested by using different concentrations of ethanol gas. The results show that the linear dynamic range of the PTR-TOFMS instrument can reach three orders of magnitude, and the detection limit can reach 3.8 ppb. At last, the PTR-TOFMS was used to detect the laboratory air to get a mass spectrum of different volatile organic compounds (VOCs). It is indicated that the newly developed PTR-TOFMS can be used for on-line monitoring trace volatile organic compounds, which will be of great value in the fields of environment, food, medicine and other fields..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 289 (2019)
Comparison Experiment of Two-Channel Self-Calibration Radiometer and Radiance Standard Detector
Mili BAI, Jianjun LI, Dongyang GAO, Youbo HU, Chenyu XIE, Jing YAN, and Xiaobing ZHENG
High-precision self-calibration radiation reference source based on spontaneous parametric down-conversion is the research hotspot of satellite remote sensing calibration. The principle of two-channel self-calibration radiometer was introduced, and a set of experimental device was established. The experimental verificaHigh-precision self-calibration radiation reference source based on spontaneous parametric down-conversion is the research hotspot of satellite remote sensing calibration. The principle of two-channel self-calibration radiometer was introduced, and a set of experimental device was established. The experimental verification was carried out by comparing with traditional radiometric standard detector. Monochromatic uniform radiance light source with 736.9 nm laser was used by integrating sphere, then the radiance at the outlet of integrating sphere was detected by two-channel self-calibration radiometer and radiance standard detector respectively. The measured absolute radiances results were 4.69×10－9 W/(sr·mm2) and 5.19×10－9 W/(sr·mm2), and the relative deviation was 9.63%. The feasibility of the principle of two-channel self-calibration radiometer was verified..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 296 (2019)
Laboratory Calibration of a Multi-Band Polarization Imager
Manchao DING, Wenchao ZHAI, Quan ZHANG, Weiwei PANG, Xin LI, and Xiaobing ZHENG
The integrated design and laboratory calibration method of a multi-band polarization imager were presented. The polarization calibration accuracy was validated by a polarized light source whose degrees of polarization (DOP) is adjustable. The results showed that the relative DOP errors of 490 nm and 670 nm band are lesThe integrated design and laboratory calibration method of a multi-band polarization imager were presented. The polarization calibration accuracy was validated by a polarized light source whose degrees of polarization (DOP) is adjustable. The results showed that the relative DOP errors of 490 nm and 670 nm band are less than 1.6% and 1.7%, respectively, when the DOP of the polarized light source is less than 0.6. The software system of the multi-band polarization imager was designed as well, and the function modules and automatic observation algorithm of the software were described in detail. Finally, the field operation stability of the instrument as well as the function and practicability of software design were verified by its field depolyment in Dunhuang radiation calibration site, Gansu, China..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 303 (2019)
Method of Surface Scratch Detection and Location of QFN Chip
Ruonan ZHANG, Chao MU, Gu ZHANG, and Xiaoqin LIU
In industrial applications, it is necessary to accurately detect scratches on the surface of a quad flat no-lead package (QFN) chip in real time. A rapid chip surface scratch detection and location method was proposed. According to image segmentation algorithm, a defect image can be acquired firstly. Then by combining In industrial applications, it is necessary to accurately detect scratches on the surface of a quad flat no-lead package (QFN) chip in real time. A rapid chip surface scratch detection and location method was proposed. According to image segmentation algorithm, a defect image can be acquired firstly. Then by combining with the contour extraction algorithm, the chip surface scratch location can be achieved. At the same time, in order to ensure real-time detection of scratches on the chip surface, image segmentation is further completed by using the Otsu multi-threshold algorithm based on particle swarm optimization (PSO) algorithm, which not only makes the defect area in the image more obvious, but also shortens the scratch detection time on the chip surface. Compared with the direct use of the Otsu algorithm, the scratch detection time on the chip surface is reduced from seconds to milliseconds, and the chip quality detection efficiency has been improved greatly. It is shown that the method has important reference value for the development and application of software systems for chip detection equipment..
Journal of Atmospheric and Environmental Optics
- Publication Date: Jan. 01, 1900
- Vol. 14, Issue 4, 313 (2019)
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