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| 1 | Vertical Distribution Characteristics of PM2.5 Observed by a Mobile Vehicle Lidar in Tianjin, China in 2016显示文摘We present mobile vehicle lidar observations in Tianjin, China during the spring, summer, and winter of 2016. Mobile observations were carried out along the city border road of Tianjin to obtain the vertical distribution characteristics of PM_(2.5). Hygroscopic growth was not considered since relative humidity was less than 60% during the observation experiments. PM_(2.5) profile was obtained with the linear regression equation between the particle extinction coefficient and PM_(2.5) mass concentration. In spring, the vertical distribution of PM_(2.5) exhibited a hierarchical structure. In addition to a layer of particles that gathered near the ground, a portion of particles floated at 0.6–2.5-km height. In summer and winter, the fine particles basically gathered below 1 km near the ground. In spring and summer, the concentration of fine particles in the south was higher than that in the north because of the influence of south wind. In winter, the distribution of fine particles was opposite to that measured during spring and summer. High concentrations of PM_(2.5) were observed in the rural areas of North Tianjin with a maximum of 350 μg m–3 on 13 December2016. It is shown that industrial and ship emissions in spring and summer and coal combustion in winter were the major sources of fine particles that polluted Tianjin. The results provide insights into the mechanisms of haze formation and the effects of meteorological conditions during haze–fog pollution episodes in the Tianjin area. | Lihui LYU Yunsheng DONG Tianshu ZHANG Cheng LIU Wenqing LIU Zhouqing XIE Yan XIANG Yi ZHANG Zhenyi CHEN Guangqiang FAN Leibo ZHANG Yang LIU Yuchen SHI Xiaowen SHU | 2018 | Journal of Meteorological Research2018，32，1： | 5 |
| 2 | Comparison of mixing layer height inversion algorithms using lidar and a pollution case study in Baoding, China显示文摘Beijing–Tianjin–Hebei area is suffering from atmospheric pollution from a long time. The understanding of the air pollution mechanism is of great importance for officials to design strategies for the environmental governance. Mixing layer height(MLH) is a key factor influencing the diffusion of air pollutants. It plays an important role on the evolution of heavy pollution events. Light detection and ranging(lidar), is an effective remote-sensing tool, which can retrieve high spatial and temporal evolution process within mixing layer(ML), especially the variation of MLH. There are many methods to retrieve MLH, but each method has its own applicable limitations. The Mie-lidar data in Beijing was firstly used to compare three different algorithms which are widely used under different pollution levels.We find that the multi-layer structure near surface may cause errors in the detection of mixing layer. The MLH retrieved based on image edge detection was better than another two methods especially under heavy polluted episode. Then we applied this method to investigate the evolution of the mixing layer height during a pollution episode in December2016. MLH at Gucheng county showed the positive correlation with the concentration of particulate matters during the start of this pollution episode. The elevated pollution level in Gucheng was not associated with MLH's decrease, and the significantly increased particulate matters raised the boundary layer, which trapped the pollutants near the surface. | Xiangguang Ji Cheng Liu Zhouqing Xie Qihou Hu Yunsheng Dong Guangqiang Fan Tianshu Zhang Chengzhi Xing Zhuang Wang Zeeshan Javed Jianguo Liu | 2019 | Journal of Environmental Sciences2019，31，5： | 5 |
| 3 | Mining geographic episode association patterns of abnormal events in global earth science data显示文摘Abnormal events in earth science have great influence on both the natural envi-ronment and the human society. Finding association patterns among these events has great significance. Because data in earth science has characteristics of mass,high dimension,spatial autocorrelation and time delay,existing mining technolo-gies cannot be directly used on it. We propose a RSNN (range-based searching nearest neighbors) spatial clustering algorithm to reduce the data size and auto-correlation. Based on the clustered data,we propose a GEAM (geographic episode association pattern mining) algorithm which can deal with events time lags and find interesting patterns with specific constraints,to mine the association patterns. We carried out experiments on global climate datasets and found many interesting association patterns. Some of the patterns are coincident with known knowledge in climate science,which indicates the correctness and feasibilities of our methods,and the others are unknown to us before,which will give new information to this research field. | WU TianShu,SONG GuoJie,MA XiuJun,XIE KunQing,GAO XiaoPing & JIN XingXing Key Laboratory of Machine Perception,Ministry of Education,and Department of Machine Intelligence,Peking University,Beijing 100871,China | 2008 | Science China(Technological Sciences)2008，51，S1： | 5 |
| 4 | Two-layered multiphoton microscopic imaging of cervical tissue显示文摘 | Shuangmu Zhuo Jianxin Chen Tianshu Luo Xingshan Jiang Shusen Xie Rong Chen | 2009 | Lasers in Medical Science2009，，3： | 1 |
| 5 | Ferroelectric,magnetic,and optical properties of Aurivillius compound Bi_(5)FeTi_(2.5)Co_(0.5)O_(15)显示文摘Bi_(5)FeTi_(2.5)Co_(0.5)O_(15)(BFTC)ceramics was successfully synthesized using the sol-gel method.It exhibits simultaneously visible-light response,ferroelectric and weak ferromagnetic orders at room temperature.The narrow band gap of 2.06 eV was determined via the UVevis diffuse absorption spectrum.The x-ray photoelectron spectroscopy results show that the Fe ions in the samples is 3 t and 2 t valence states while the doped Co ions is 2 t valence state.The BFTC sample undergoes a ferromagnetic-like transition at~552 K.Weak ferromagnetism is mainly due to spin-canting of Fe-based and Co-based sublattices via Dzyaloshinskii-Moriya(DM)interaction.Dielectric loss and dielectric modulus exhibit the characteristics of dielectric relaxation,which can be ascribed to oxygen/vacancy hopping.These results reveal many potentially useful physical phenomena and open a new avenue to design of novel solar-energy conversion devices and multiferroic applications. | Hui Sun Yuying Wu Xi Xie Yuxi Lu Tianshu Yao Jiansheng Zhong Xiaobing Chen | 2018 | Journal of Materiomics2018，4，4： | 0 |
| 6 | Antioxidant mechanism of modified Qiongyu paste against aging based on network pharmacology and experimental validation显示文摘Objective:To provide a possible basis for the anti-aging effect of modified Qiongyu paste(MQP).Methods:Ultra-high-performance liquid chromatography-Q-Orbitrap mass spectrometry was applied to confirm the effective components of MQP that we had identified from databases and research literature.Then,network pharmacology was employed to predict the possible underlying mechanism of MQP against aging.According to the overlap with age-related gene targets,we obtained key targets of MQP against aging using protein-protein interaction analyses.Superoxide dismutase(SOD)tests were performed in vitro and in vivo.Western blotting of P62 and LC3B and quantitative polymerase chain reaction of the expression of the P62,LC3B,HO-1,Keap1,and Nrf2 genes were conducted on H_(2)O_(2) -induced PC12 cells.Enzyme-linked immunosorbent assays of tumor necrosis factor-a and interleukin-6 were conducted on a D-galactose-induced aging mice model.Results:A total of 44 compounds in MQP were finally identified,and 48 gene targets were considered related to anti-aging.Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses linked the principal anti-aging mechanisms of MQP to oxidative resistance,genomic stabilization,and growth hormone regulation.In vitro,H_(2)O_(2)-induced PC12 cells showed that MQP was able to activate SOD,prolong telomeres,and enhance the expression levels of P62,LC3B,HO-1,Keap1,and Nrf2.The quantitative polymerase chain reaction results were affirmed with the reactive oxygen species inhibitor N-acetylcysteine and the reactive oxygen species agonist diallyl-tetrasulfide.In vivo,the D-gal-induced aging mice showed that MQP increased SOD in the brain and reduced tumor necrosis factor-α and interleukin-6 in the serum.Thus,our results suggest that the mechanism of the anti-aging effect of MQP primarily involves antagonizing oxidative stress.Conclusion:From the analyses and experimental validation,we may conclude that oxidative stress resistance may be a potential mechanism of the MQP anti-aging effect. | Tianshu Xie Qi Ding Siwen Feng Zimin Liu Yuanyuan Shi | 2022 | Journal of Traditional Chinese Medical Sciences2022，9，4： | 0 |
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