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PM2.5 over North China based on MODIS AOD and effect of meteorological elements during 2003‒2015

Youfang Chen, Yimin Zhou, Xinyi Zhao

《环境科学与工程前沿（英文）》 2020年 第14卷 第2期 doi: 10.1007/s11783-019-1202-8

摘要： The Taihang Mountains was the boundary between high and low pollution areas. There were one high value center for PM2.5 pollution and two low value centers. In 2004, 2009 and after 2013, PM2.5 concentration was relatively low. Over the past 40 years, PM2.5 pollution in North China has become increasingly serious and progressively exposes the densely populated areas to pollutants. However, due to limited ground data, it is challenging to estimate accurate PM2.5 exposure levels, further making it unfavorable for the prediction and prevention of PM2.5 pollutions. This paper therefore uses the mixed effect model to estimate daily PM2.5 concentrations of North China between 2003 and 2015 with ground observation data and MODIS AOD satellite data. The tempo-spatial characteristics of PM2.5 and the influence of meteorological elements on PM2.5 is discussed with EOF and canonical correlation analysis respectively. Results show that overall R2 is 0.36 and the root mean squared predicted error was 30.1 μg/m3 for the model prediction. Our time series analysis showed that, the Taihang Mountains acted as a boundary between the high and low pollution areas in North China; while the northern part of Henan Province, the southern part of Hebei Province and the western part of Shandong Province were the most polluted areas. Although, in 2004, 2009 and dates after 2013, PM2.5 concentrations were relatively low. Meteorological/topography conditions, that include high surface humidity of area in the range of 34°‒40°N and 119°‒124°E, relatively low boundary layer heights, and southerly and easterly winds from the east and north area were common factors attributed to haze in the most polluted area. Overall, the spatial distribution of increasingly concentrated PM2.5 pollution in North China are consistent with the local emission level, unfavorable meteorological conditions and topographic changes.

关键词： Aerosol optical depth     PM2.5     MODIS     Mixed effect model     Canonical correlation analysis    

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小粒径和球形气溶胶对2003—2018年陆地总气溶胶光学厚度下降趋势贡献显著 Article

桂柯, 车慧正,李雷,郑宇,张磊,赵胡笳,仲峻霆,要文瑞,梁苑新,王亚强,张小曳

《工程（英文）》 2022年 第16卷 第9期   页码 82-92 doi: 10.1016/j.eng.2021.05.017

摘要：

气溶胶光学和微物理特性是估计大气气溶胶气候强迫最大的不确定性之一。尽管气溶胶光学厚度（AOD）在全球及区域尺度上的演变趋势已经得到了广泛的研究，但对与气溶胶粒子特性相关的类型依赖AOD的变化趋势仍然知之甚少。在此，本研究利用多角度成像光谱辐射计（MISR）反演的气溶胶光学特性数据集，研究了2003—2018 年期间陆地总AOD（TAOD）及其按粒径大小和粒形分离的类型依赖AOD的10 年尺度趋势，分析了TAOD趋势和不同类型AOD演变之间的关系，并量化了不同类型AOD对TAOD趋势的相对贡献。通过将TAOD值分别按0.15、0.40 和0.80 的阈值划分为4 个不同的气溶胶污染等级（APL），进一步探讨了TAOD演变与APL 发生频率年际变化之间的关系。研究结果表明，2003—2018 年期间，除南亚地区外，大多数陆地区域的空气质量都有明显改善，表现为从轻度污染转变为清洁状态。然而，不同的APL对TAOD变化的影响及其相关程度具有显著的区域性差异。此外，自2003 年以来，陆地上的年均TAOD下降趋势达到0.47%⋅a−1 （通过95%置信度检验）。这种显著减少主要归因于小粒径（直径小于0.7 mm）AOD（SAOD）和球形AOD（SPAOD）的持续减少（分别为−0.74%⋅a−1和−0.46%⋅a−1）。统计分析表明，SAOD和SPAOD分别占TAOD的57.5%和89.6%，但对TAOD的趋势贡献可达82.6%和90.4%。最后，研究表明由硫酸盐、有机物和黑碳气溶胶组成的小粒径和球形气溶胶在驱动陆地TAOD年际变化中起主导作用。

关键词： 气溶胶光学厚度     多角度成像光谱辐射计     气溶胶污染等级     气溶胶类型     粒径和粒形    

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Investigating the raveling test for full-depth reclamation

Robert HILL, Andrew BRAHAM

《结构与土木工程前沿（英文）》 2018年 第12卷 第2期   页码 222-226 doi: 10.1007/s11709-017-0423-9

摘要： Full-Depth Reclamation (FDR) is a sustainable method of building pavement structure compared to more traditional rehabilitation methods. Traffic is generally returned to an FDR project before a surface course is applied, as water in the FDR needs time to evaporate from the structure. This should not be done too quickly or raveling occurs. Currently, there is no test to quantify the timing of return to traffic. In this study, the “Raveling test of cold mixed bituminous emulsion samples” (ASTM D7196) was used to compare asphalt emulsion and asphalt foam FDR. Asphalt emulsion samples were cured at ambient and 40 °C temperatures, while asphalt foam samples were cured at ambient temperatures. Raveling test data was collected from 0 to 48 hours of curing, however, samples were often not able to withstand fifteen minutes of testing. Therefore, the “time lasted” (the time the raveling head loses contact with the surface of the sample) was recorded. In general, the asphalt emulsion samples that were cured in the oven at 40 °C had a longer time lasted and showed higher potential for determination of return to traffic. In addition, the asphalt emulsion samples had a longer time lasted than the asphalt foam samples at ambient temperatures.

关键词： raveling     full depth reclamation    

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Physical and chemical processes of wintertime secondary nitrate aerosol formation

Qi YING

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 348-361 doi: 10.1007/s11783-011-0343-1

摘要： The UCD/CIT model was modified to include a process analysis (PA) scheme for gas and particulate matter (PM) to study the formation of secondary nitrate aerosol during a stagnant wintertime air pollution episode during the California Regional PM /PM Air Quality Study (CRPAQS) where detailed measurements of PM components are available at a few sites. Secondary nitrate is formed in the urban areas from near the ground to a few hundred meters above the surface during the day with a maximum modeled net increase rate of 4 μg·m ·d during the study episode. The secondary nitrate formation rate in rural areas is lower due to lower NO . In the afternoon hours, near-surface temperature can be high enough to evaporate the particulate nitrate. In the nighttime hours, both the gas phase N O reactions with water vapor and the N O heterogeneous reactions with particle-bound water are important for secondary nitrate formation. The N O reactions are most import near the surface to a few hundred meters above surface with a maximum modeled net secondary nitrate increase rate of 1 μg·m ·d and are more significant in the rural areas where the O concentrations are high at night. In general, vertical transport during the day moves the nitrate formed near the surface to higher elevations. During the stagnant days, process analysis indicates that the nitrate concentration in the upper air builds up and leads to a net downward flux of nitrate through vertical diffusion and a rapid increase of surface nitrate concentration.

关键词： secondary nitrate aerosol     N2O5 heterogeneous reaction     process analysis    

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Design and calibration of a new high-definition three-dimensional laparoscopic system

Jia TANG,Li-qiang WANG,Bo YUAN,Hong JIANG,Qi-ming ZHU

《信息与电子工程前沿（英文）》 2015年 第16卷 第1期   页码 79-84 doi: 10.1631/FITEE.1400149

摘要： We present a high-definition (HD) 3D laparoscopic system including a dual channel optical system, two cameras, a camera control unit (CCU), and an HD 3D monitor. This laparoscopic system is capable of outputting dual high-definition videos and providing vivid 3D images. A modified pinhole camera model is used for camera calibration and a new method of depth measurement to improve precision. The average error of depth measurement measured by experiment (about 1.13 mm) was small in proportion to the large range in distance of the system (10-150 mm). The new method is applicable to any calibrated binocular vision system.

关键词： Dual optical channels     Three dimensional     Camera calibration     Pinhole model     Depth measurement     Laparoscopic system    

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Computational fluid dynamics simulation of aerosol transport and deposition

Yingjie TANG, Bing GUO

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 362-377 doi: 10.1007/s11783-011-0365-8

摘要： In this article computational fluid dynamics (CFD) simulation of aerosol transport and deposition, i.e. the transport and deposition of particles in an aerosol, is reviewed. The review gives a brief account of the basics of aerosol mechanics, followed by a description of the general CFD approach for flow field simulation, turbulence modeling, wall treatments and simulation of particle motion and deposition. Then examples from the literature are presented, including CFD simulation of particle deposition in human respiratory tract and particle deposition in aerosol devices. CFD simulation of particle transport and deposition may provide information that is difficult to obtain through physical experiments, and it may help reduce the number of experiments needed for device design. Due to the difficulty of describing turbulent flow and particle-eddy interaction, turbulent dispersion of particles remains one of the greatest challenges for CFD simulation. However, it is possible to take a balanced approach toward quantitative description of aerosol dispersion using CFD simulation in conjunction with empirical relations.

关键词： computational fluid dynamics (CFD)     aerosol     transport     deposition    

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Calculation of collision frequency function for aerosol particles in free molecule regime in presence

Xiaowei LUO, Yannick BENICHOU, Suyuan YU

《能源前沿（英文）》 2013年 第7卷 第4期   页码 506-510 doi: 10.1007/s11708-013-0275-5

摘要： The collision frequency function for aerosol particles has already been calculated for the free molecule regime and for the continuum range. The present work, taking into account the influence of internal force fields such as magnetic force, electric force and molecular forces, created by particles themselves, recalculated the collision frequency in the case of particles much smaller than the mean free path of the gas (free molecule regime). Attractive forces increase naturally the collision frequency, while repulsive forces decrease it. The calculation was performed for all types of central forces deriving from a potential, including Coulomb forces and Van der Waals forces.

关键词： aerosol particles     collision frequency function     coagulation    

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Multivariable regression model for Fox depth correction factor

Ravi Kant MITTAL, Sanket RAWAT, Piyush BANSAL

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 103-109 doi: 10.1007/s11709-018-0474-6

摘要： This paper presents a simple and efficient equation for calculating the Fox depth correction factor used in computation of settlement reduction due to foundation embedment. Classical solution of Boussinesq theory was used originally to develop the Fox depth correction factor equations which were rather complex in nature. The equations were later simplified in the form of graphs and tables and referred in various international code of practices and standard texts for an unsophisticated and quick analysis. However, these tables and graphs provide the factor only for limited values of the input variables and hence again complicates the process of automation of analysis. Therefore, this paper presents a non-linear regression model for the analysis of effect of embedment developed using “IBM Statistical Package for the Social Sciences” software. Through multiple iterations, the value of coefficient of determination is found to reach 0.987. The equation is straightforward, competent and easy to use for both manual and automated calculation of the Fox depth correction factor for wide range of input values. Using the developed equation, parametric study is also conducted in the later part of the paper to analyse the extent of effect of a particular variable on the Fox depth factor.

关键词： settlement     embedment     Fox depth correction factor     regression     multivariable    

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Aerosol exposure assessment during reclaimed water utilization in China and risk evaluation in case of

《环境科学与工程前沿（英文）》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1516-1

摘要：

• The Chinese population exposure habits were surveyed.

关键词： Legionella     QMRA     Reclaimed water     Aerosol     Water reuse    

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Response of organic aerosol characteristics to emission reduction in Yangtze River Delta region

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1714-0

摘要：

● The emission reduction causes significant change in organic aerosol composition.

关键词： Emission control     Secondary organic aerosol     Atmospheric oxidizing capacity     Holiday effects     COVID-19 lockdown    

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Formation of secondary inorganic aerosol in a frigid urban atmosphere

《环境科学与工程前沿（英文）》 2022年 第16卷 第2期 doi: 10.1007/s11783-021-1452-0

摘要：

•Harbin showed relatively high threshold RH (80%) for apparent increase of SOR.

关键词： Haze     Sulfate     Nitrate     Heterogeneous chemistry     Biomass burning     Northeast China    

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Effects of two transition metal sulfate salts on secondary organic aerosol formation in toluene/NO

Biwu CHU, Jiming HAO, Junhua LI, Hideto TAKEKAWA, Kun WANG, Jingkun JIANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第1期   页码 1-9 doi: 10.1007/s11783-012-0476-x

摘要： Aerosol phase reactions play a very important role on secondary organic aerosol (SOA) formation, and metal-containing aerosols are important components in the atmosphere. In this study, we tested the effects of two transition metal sulfate salts, manganese sulfate (MnSO ) and zinc sulfate (ZnSO ), on the photochemical reactions of a toluene/NO photooxidation system in a 2 m smog chamber. By comparing photochemical reaction products of experiments with and without transition metal sulfate seed aerosols, we evaluated the effects of transition metal sulfate seed aerosols on toluene consumption, NO conversion and the formation of ozone and SOA. MnSO and ZnSO seed aerosols were found to have similar effects on photochemical reactions, both enhance the SOA production, while showing negligible effects on the gas phase compounds. These observations are consistent when varying metal sulfate aerosol concentrations. This is attributed to the catalytic effects of MnSO and ZnSO seed aerosols which may enhance the formation of condensable semivolatile compounds. Their subsequent partitioning into the aerosol phase leads to the observed SOA formation enhancement.

关键词： manganese sulfate     zinc sulfate     seed aerosols     toluene photooxidation     secondary organic aerosol    

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How aerosol direct effects influence the source contributions to PM

Litao Wang, Joshua S. Fu, Wei Wei, Zhe Wei, Chenchen Meng, Simeng Ma, Jiandong Wang

《环境科学与工程前沿（英文）》 2018年 第12卷 第3期 doi: 10.1007/s11783-018-1014-2

摘要： Beijing-Tianjin-Hebei area is the most air polluted region in China and the three neighborhood southern Hebei cities, Shijiazhuang, Xingtai, and Handan, are listed in the top ten polluted cities with severe PM pollution. The objective of this paper is to evaluate the impacts of aerosol direct effects on air quality over the southern Hebei cities, as well as the impacts when considering those effects on source apportionment using three dimensional air quality models. The WRF/Chem model was applied over the East Asia and northern China at 36 and 12 km horizontal grid resolutions, respectively, for the period of January 2013, with two sets of simulations with or without aerosol-meteorology feedbacks. The source contributions of power plants, industrial, domestic, transportation, and agriculture are evaluated using the Brute-Force Method (BFM) under the two simulation configurations. Our results indicate that, although the increases in PM concentrations due to those effects over the three southern Hebei cities are only 3%–9% on montly average, they are much more significant under high PM loadings (~50 μg·m when PM concentrations are higher than 400 μg m ). When considering the aerosol feedbacks, the contributions of industrial and domestic sources assessed using the BFM will obviously increase (e.g., from 30%–34% to 32%–37% for industrial), especially under high PM loadings (e.g., from 36%–44% to 43%–47% for domestic when PM >400 μg·m ). Our results imply that the aerosol direct effects should not be ignored during severe pollution episodes, especially in short-term source apportionment using the BFM.

关键词： Aerosol direct effect     PM2.5     Southern Hebei     WRF/Chem     Haze    

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Particle swarm optimization model to predict scour depth around a bridge pier

Shahaboddin SHAMSHIRBAND, Amir MOSAVI, Timon RABCZUK

《结构与土木工程前沿（英文）》 2020年 第14卷 第4期   页码 855-866 doi: 10.1007/s11709-020-0619-2

摘要： Scour depth around bridge piers plays a vital role in the safety and stability of the bridges. The former approaches used in the prediction of scour depth are based on regression models or black box models in which the first one lacks enough accuracy while the later one does not provide a clear mathematical expression to easily employ it for other situations or cases. Therefore, this paper aims to develop new equations using particle swarm optimization as a metaheuristic approach to predict scour depth around bridge piers. To improve the efficiency of the proposed model, individual equations are derived for laboratory and field data. Moreover, sensitivity analysis is conducted to achieve the most effective parameters in the estimation of scour depth for both experimental and filed data sets. Comparing the results of the proposed model with those of existing regression-based equations reveal the superiority of the proposed method in terms of accuracy and uncertainty. Moreover, the ratio of pier width to flow depth and ratio of 50 (mean particle diameter) to flow depth for the laboratory and field data were recognized as the most effective parameters, respectively. The derived equations can be used as a suitable proxy to estimate scour depth in both experimental and prototype scales.

关键词： scour depth     bridge design and construction     particle swarm optimization     computational mechanics     artificial intelligence     bridge pier    

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Secondary aerosol formation in winter haze over the Beijing-Tianjin-Hebei Region, China

Dongjie Shang, Jianfei Peng, Song Guo, Zhijun Wu, Min Hu

《环境科学与工程前沿（英文）》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1326-x

摘要： Abstract • Characteristics and interannual variation of aerosol pollution are illustrated. • Mechanisms of secondary aerosol formation in winter haze of North China are reviewed. • Directions in future studies of secondary aerosol formation are provided. Severe haze pollution occurs frequently in the winter over the Beijing-Tianjin-Hebei (BTH) region (China), exerting profound impacts on air quality, visibility, and human health. The Chinese Government has taken strict mitigation actions since 2013 and has achieved a significant reduction in the annual mean PM2.5 concentration over this region. However, the level of secondary aerosols during heavy haze episodes showed little decrease during this period. During heavy haze episodes, the concentrations of secondary aerosol components, including sulfate, nitrate and secondary organics, in aerosol particles increase sharply, acting as the main contributors to aerosol pollution. To achieve effective control of particle pollution in the BTH region, the precise and complete secondary aerosol formation mechanisms have been investigated, and advances have been made about the mechanisms of gas phase reaction, nucleation and heterogeneous reactions in forming secondary aerosols. This paper reviews the research progress in aerosol chemistry during haze pollution episodes in the BTH region, lays out the challenges in haze formation studies, and provides implications and directions for future research.

关键词： Secondary aerosol formation     Regional haze     Photochemical reaction     Aqueous reaction     Chemical mechanism    

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标题 作者 时间 类型 操作

PM2.5 over North China based on MODIS AOD and effect of meteorological elements during 2003‒2015

Youfang Chen, Yimin Zhou, Xinyi Zhao

期刊论文

小粒径和球形气溶胶对2003—2018年陆地总气溶胶光学厚度下降趋势贡献显著

桂柯, 车慧正,李雷,郑宇,张磊,赵胡笳,仲峻霆,要文瑞,梁苑新,王亚强,张小曳

期刊论文

Investigating the raveling test for full-depth reclamation

Robert HILL, Andrew BRAHAM

期刊论文

Physical and chemical processes of wintertime secondary nitrate aerosol formation

Qi YING

期刊论文

Design and calibration of a new high-definition three-dimensional laparoscopic system

Jia TANG,Li-qiang WANG,Bo YUAN,Hong JIANG,Qi-ming ZHU

期刊论文

Computational fluid dynamics simulation of aerosol transport and deposition

Yingjie TANG, Bing GUO

期刊论文

Calculation of collision frequency function for aerosol particles in free molecule regime in presence

Xiaowei LUO, Yannick BENICHOU, Suyuan YU

期刊论文

Multivariable regression model for Fox depth correction factor

Ravi Kant MITTAL, Sanket RAWAT, Piyush BANSAL

期刊论文

Aerosol exposure assessment during reclaimed water utilization in China and risk evaluation in case of

期刊论文

Response of organic aerosol characteristics to emission reduction in Yangtze River Delta region

期刊论文

Formation of secondary inorganic aerosol in a frigid urban atmosphere

期刊论文

Effects of two transition metal sulfate salts on secondary organic aerosol formation in toluene/NO

Biwu CHU, Jiming HAO, Junhua LI, Hideto TAKEKAWA, Kun WANG, Jingkun JIANG

期刊论文

How aerosol direct effects influence the source contributions to PM

Litao Wang, Joshua S. Fu, Wei Wei, Zhe Wei, Chenchen Meng, Simeng Ma, Jiandong Wang

期刊论文

Particle swarm optimization model to predict scour depth around a bridge pier

Shahaboddin SHAMSHIRBAND, Amir MOSAVI, Timon RABCZUK

期刊论文

Secondary aerosol formation in winter haze over the Beijing-Tianjin-Hebei Region, China

Dongjie Shang, Jianfei Peng, Song Guo, Zhijun Wu, Min Hu

期刊论文