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1,053 results on '"Zhao, Zhijun"'

1. Image-based retrieval of all-day cloud physical parameters for FY4A/AGRI and its application over the Tibetan Plateau

Author

Zhao, Zhijun, Zhang, Feng, Li, Wenwen, and Li, Jingwei

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

Satellite remote sensing serves as a crucial means to acquire cloud physical parameters. However, existing official cloud products derived from the advanced geostationary radiation imager (AGRI) onboard the Fengyun-4A geostationary satellite suffer from limitations in computational precision and efficiency. In this study, an image-based transfer learning model (ITLM) was developed to realize all-day and high-precision retrieval of cloud physical parameters using AGRI thermal infrared measurements and auxiliary data. Combining the observation advantages of geostationary and polar-orbiting satellites, ITLM was pre-trained and transfer-trained with official cloud products from advanced Himawari imager (AHI) and Moderate Resolution Imaging Spectroradiometer (MODIS), respectively. Taking official MODIS products as the benchmarks, ITLM achieved an overall accuracy of 79.93% for identifying cloud phase and root mean squared errors of 1.85 km, 6.72 um, and 12.79 for estimating cloud top height, cloud effective radius, and cloud optical thickness, outperforming the precision of official AGRI and AHI products. Compared to the pixel-based random forest model, ITLM utilized the spatial information of clouds to significantly improve the retrieval performance and achieve more than a 6-fold increase in speed for a single full-disk retrieval. Moreover, the AGRI ITLM products with spatiotemporal continuity and high precision were used to accurately describe the spatial distribution characteristics of cloud fractions and cloud properties over the Tibetan Plateau (TP) during both daytime and nighttime, and for the first time provide insights into the diurnal variation of cloud cover and cloud properties for total clouds and deep convective clouds across different seasons.

Published
2024

13. Establishment and application of a TaqMan-based real-time fluorescence quantitative PCR detection method for Clostridium perfringens

Author

MA Jiaqi, SUN Bo, MA Hongmei, WANG Dong, ZHAO Zhijun, LI Yong, and ZENG Jin

Subjects
clostridium perfringens, real-time fluorescent quantitative pcr, taqman probe method, water sample detection, foodborne pathogens, Food processing and manufacture, TP368-456, Nutrition. Foods and food supply, TX341-641
Abstract

ObjectiveA TaqMan-based real-time fluorescence quantitative polymerase chain reaction （PCR） method was established to detect Clostridium perfringens （C. perfringens） in tap water samples.MethodsThe highly conserved plc gene located in the pseudonucleus of the bacterium was amplified and specific primers and TaqMan probes were designed. After optimization， a TaqMan-based real-time fluorescence quantitative PCR detection method was established. Combined with the filter membrane method， simulated polluted water samples of standard strains containing plc genes were treated， and the established method was tested.ResultsThe established TaqMan-based method for detecting C. perfringens showed high specificity. Ct >40 were found in 13 foodborne pathogens， 3 Clostridium difficile and 1 Clostridium putrefaciens strain. The detection limit of this method was 1×10 copies/μL， showing high sensitivity. The minimum detection limit for the simulated polluted water sample was 1.0×102 CFU/mL. This method was also used to detect 4 simulated water contamination samples and 90 imported water samples. The results showed that C. perfringens could be detected in 2 simulated 1.0×102 CFU/mL-contaminated water samples， while not in 2 simulated 1.0×10 CFU/mL-contaminated and imported water samples.ConclusionThe TaqMan real-time fluorescence quantitative PCR method established in this study for the detection of C. perfringens has good specificity， high sensitivity， and practical value for detecting C. perfringens in water samples.

Published
2024
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20. Research and Application of Real-Time Measurement Method of Engine Oil Consumption

Author

Liu, Zhiyong, Li, Xiao, Zhao, Zhijun, Zhu, Weijian, Xu, Zhengxin, Wang, Yue, Zhang, Lin, China Society of Automotive Engineers, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, and Zhang, Junjie James, Series Editor

Published
2023
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26. The estimate of sensitivity for large infrared telescopes based on measured sky brightness and atmospheric extinction

Author

Zhao, Zhijun, Zhou, Haijing, Zhang, Yuchen, Ling, Yun, and Xu, Fangyu

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

In order to evaluate the ground-based infrared telescope sensitivity affected by the noise from the atmosphere, instruments and detectors, we construct a sensitivity model that can calculate limiting magnitudes and signal-to-noise ratio ($S/N$). The model is tested with tentative measurements of $\rm M'$-band sky brightness and atmospheric extinction obtained at the Ali and Daocheng sites. We find that the noise caused by an excellent scientific detector and instruments at $-135^\circ \rm C$ can be ignored compared to the $\rm M'$-band sky background noise. Thus, when $S/N=3$ and total exposure time is 1 second for 10 m telescopes, the magnitude limited by the atmosphere is $13.01^{\rm m}$ at Ali and $12.96^{\rm m}$ at Daocheng. Even under less-than-ideal circumstances, i.e., the readout noise of a deep cryogenic detector is less than $200e^-$ and the instruments are cooled to below $-87.2^\circ \rm C$, the above magnitudes decrease by $0.056^{\rm m}$ at most. Therefore, according to observational requirements with a large telescope in a given infrared band, astronomers can use this sensitivity model as a tool for guiding site surveys, detector selection and instrumental thermal-control., Comment: 13 pages, 12 figures. Accepted for publication in Research in Astronomy and Astrophysics

Published
2020
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33. Rice’s trajectory from wild to domesticated in East Asia

Author

Zhang, Jianping, primary, Jiang, Leping, additional, Yu, Lupeng, additional, Huan, Xiujia, additional, Zhou, Liping, additional, Wang, Changsheng, additional, Jin, Jianhui, additional, Zuo, Xinxin, additional, Wu, Naiqin, additional, Zhao, Zhijun, additional, Sun, Hanlong, additional, Yu, Zhaoyuan, additional, Zhang, Guoping, additional, Zhu, Jiangping, additional, Wu, Zhenlei, additional, Dong, Yajie, additional, Fan, Baoshuo, additional, Shen, Caiming, additional, and Lu, Houyuan, additional

Published
2024
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47. Wheel and Track Hybrid Planetary Surface Locomotion Mechanism

Author

Zhao, Zhijun, Zhang, Yun, Wang, Kang, Wang, Yaobing, Ni, Wencheng, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Liu, Xin-Jun, editor, Nie, Zhenguo, editor, Yu, Jingjun, editor, Xie, Fugui, editor, and Song, Rui, editor

Published
2021
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48. Design and Engineering Realization of the Joint for Chang’E-5 Surface Sampling Arm

Author

Wang, Kang, Ni, Wencheng, Zhao, Zhijun, Liu, Xin, Wang, Yaobing, Jiang, Shuiqing, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Liu, Xin-Jun, editor, Nie, Zhenguo, editor, Yu, Jingjun, editor, Xie, Fugui, editor, and Song, Rui, editor

Published
2021
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