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Estimation of extreme wind pressure coefficient in a zone by multivariate extreme value theory
Qing-shan Yang,Danyu Li,Yi Hui,Siu-Seong Law 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.31 No.3
Knowledge on the design value of extreme wind pressure coefficients (EWPC) of a specific zone of buildings is essential for the wind-resistant capacity of claddings. This paper presents a method to estimate the representative EWPC introducing the multivariate extreme value model. The spatial correlations of the extreme wind pressures at different locations can be consider through the multivariate extreme value. The moving average method is also adopted in this method, so that the measured point pressure can be converted to wind pressure of an area. The proposed method is applied to wind tunnel test results of a large flat roof building. Comparison with existing methods shows that it can give a good estimation for all target zones with different sizes.
Wei Yang,Jinfeng Xia,Guohong Zhou,Tianxi Hu,Danwang Ye,Danyu Jiang,Qiang Li 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.5
In this study, a terbium(?) complex, Tb(SSA)4 (SSA?=?sulfosalicylate), was synthesized and employed to detect toxic chromate anion (CrO42?) as a visually identifiable probe. Luminescence investigations confirmed that the Tb complex is an excellent probe with high selectivity, high sensitivity (I0/I100 ?M = 9.5), and a low detection limit (2.8???10?8 M), targeting CrO42? in aqueous solution. The simple fluorescence-based probe can be quickly and easily prepared, and enables the reliable, visual detection of CrO42? ion in daily applications.
Feature analysis on air quality in the main urban area of Nanchong City in 2015–2018
Xiong Lei,Qing Zheng,Yifan Qian,Jian Hu,Danyu Li,Ping Zhang,Xu Yuan,Qiumei Quan,Yunxiang Li 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.3
This study evaluates the air quality in Nanchong City in 2015–2018 based on automatic monitoring data and meteorological data in the main urban area. Results show that overall air quality in the main urban area of Nanchong was standard and improved from 2015 to 2018. SO₂, NO₂, and CO had slight influences on air quality in the study area, whereas excessive annual average PM2.5 and increasing O₃ concentration challenged the air quality. The monthly average mass concentrations of particulate matters (PM2.5 and PM10), NO₂, and CO generally presented a “U-shaped” distribution pattern while O₃ showed the opposite. The diurnal variation of PM, NO₂, and CO has two peaks related to the morning and evening rush hours. Vehicle exhaust is the main source of local pollution. Over-standard PM2.5 can significantly inhibit O₃ production while O₃ can easily promote the secondary generation of PM2.5 due to its strong oxidization. PM2.5 emission should be controlled strictly in winter, while in summer, the sources of O₃ should be controlled vigorously. Air pollution is comprehensive and complicated and is influenced by various factors, mainly meteorological and human factors. Measures such as artificial rainfall should be included at the appropriate time to cope with adverse meteorological conditions when heavy pollution occurs in winter.
Yifan Qian,Xu Yuan,Wen Dou,Jian Hu,Jie Xia,Danyu Li,Qing Zheng,Ping Zhang,Qiumei Quan,Yunxiang Li 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.2
The sources and variation trend of ambient air pollutants, the duration of pollution process and the conditions for decontamination were analyzed in this essay based on the ambient air pollutants data, PM<SUB>2.5</SUB> source analysis data and meteorological factors in Nanchong City during 2014 to 2019. The results indicated that the concentrated discharge of fireworks on New Year’s Eve was the main reason for the sharp deterioration of the ambient air quality. PM<SUB>2.5</SUB> and PM<SUB>10</SUB> concentrations increased significantly after fireworks were set off, and the peak value appeared at about 02:00 on the Lunar New Year’s Day, but the value of PM<SUB>2.5</SUB>/PM<SUB>10</SUB> did not change significantly. The concentration of SO₂ in gaseous pollutants was slightly affected by fireworks, while NO₂, CO and O₃ were not affected basically. Having been affected by fireworks, the concentrations and percentages of K⁺, Cl⁻ and Mg<SUP>2+</SUP> of the water-solubility ions in PM<SUB>2.5</SUB> significantly increased at the 0.01 level. Meanwhile, the concentrations and percentages of the metal elements, including Cu, Pb, Mg, Al, K and Ba, significantly increased at the 0.05 level. Restricted to the topography and meteorological factors, the duration of the pollution was prolonged.