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Single particle analysis of ambient aerosols in Shanghai during the World Exposition, 2010: two case studies

Shikang TAO, Xinning WANG, Hong CHEN, Xin YANG, Mei LI, Lei LI, Zhen ZHOU

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 391-401 doi: 10.1007/s11783-011-0355-x

摘要： A TSI Model 3800 aerosol time-of-flight mass spectrometer (ATOFMS) was deployed for single-particle analysis in Shanghai during the World Exposition (EXPO), 2010. Measurements on two extreme cases: polluted day (1st May) and clean day (25th September) were compared to show how meteorological conditions affected the concentration and composition of ambient aerosols. Mass spectra of 90496 and 50407 particles were analyzed respectively during the two sampling periods. The ART-2a neural network algorithm was applied to sort the collected particles. Seven major classes of particles were obtained: dust, sea salt, industrial, biomass burning, organic carbon (OC), elementary carbon (EC), and NH -rich particles. Number concentration of ambient aerosols showed a strong anti-correlation with the boundary layer height variation. The external mixing states of aerosols were quite different during two sampling periods because of different air parcel trajectories. Number fraction of biomass burning particles (43.3%) during polluted episode was much higher than that (21.6%) of clean time. Air parcels from the East China Sea on clean day diluted local pollutant concentration and increased the portion of sea salt particle dramatically (13.3%). The large contribution of biomass burning particles in both cases might be an indication of a constant regional background of biomass burning emission. Mass spectrum analysis showed that chemical compositions and internal mixing states of almost all the particle types were more complicate during polluted episode compared with those observed in clean time. Strong nitrate signals in the mass spectra suggested that most of the particles collected on polluted day had gone through some aging processes before reaching the sampling site.

关键词： ambient aerosol     aerosol time-of-flight mass spectrometer     Shanghai     world exposition    

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Characterization of submicron aerosols in the urban outflow of the central Pearl River Delta region of China

Zhaoheng GONG, Zijuan LAN, Lian XUE, Liwu ZENG, Lingyan HE, Xiaofeng HUANG

《环境科学与工程前沿（英文）》 2012年 第6卷 第5期   页码 725-733 doi: 10.1007/s11783-012-0441-8

摘要： Submicron aerosol particles (with aerodynamic diameters less than 1 μm, PM ) were sampled and measured in Heshan, an urban outflow site of Guangzhou megacity in Pearl River Delta in South China, using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) in November 2010 during 2010 Guangzhou Asian Games. The mean PM mass concentration measured was 47.9±17.0 μg·m during the campaign, with organic aerosol (OA) and sulfate being the two dominant species, accounting for 36.3% and 20.9% of the total mass, respectively, followed by black carbon (17.1%, measured by an aethalometer), nitrate (12.9%), ammonium (9.6%) and chloride (3.1%). The average size distributions of the species (except black carbon) were dominated by an accumulation mode peaking at ~550 nm. Calculations based on high-resolution organic mass spectrum showed that, C, H, O and N on average contributed 58.1%, 7.3%, 30.7%, and 3.9% to the total organic mass, respectively. The average ratio of organic mass over organic carbon mass (OM/OC) was 1.73±0.08. Four components of OA were identified by the Positive Matrix Factorization (PMF) analysis, including a hydrocarbon-like (HOA), a biomass burning (BBOA) and two oxygenated (SV-OOA and LV-OOA) organic aerosol components, which on average accounted for 18.0%, 14.3%, 28.8% and 38.9% of the total organic mass, respectively.

关键词： organic aerosol     high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS)     positive matrix factorization    

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Determination of persistent organic pollutants by gas chromatography/laser multiphoton ionization/time-of-flightmass spectrometry

Osamu SHITAMICHI, Taiki MATSUI, Yamei HUI, Weiwei CHEN, Totaro IMASAKA

《环境科学与工程前沿（英文）》 2012年 第6卷 第1期   页码 26-31 doi: 10.1007/s11783-011-0374-7

摘要： An authentic mixture of polychlorinated biphenyls was measured using a short wide-bore capillary column for the group separation of major components present in an actual sample of Kanechlor. The limits of detection were improved by ca. 2 fold in comparison with those obtained using a conventional capillary column, since the retention time was reduced and the amount of analytes introduced into the mass spectrometer per unit time could be increased. On the other hand, surface-water and sediment samples containing polycyclic aromatic hydrocarbons (PAHs) were collected from the river located in the vicinity of a waste water treatment plant. Even acenaphthylene, a minor component of the mixture could be measured for the sediment sample, and the concentrations were determined for several heavy PAHs. As demonstrated, a technique involving laser multiphoton ionization/time-of-flight mass spectrometry was useful as a sensitive and selective analytical tool for the trace analysis of persistent organic pollutants in an environmental sample.

关键词： polychlorinated biphenyls (PCBs)     polycyclic aromatic hydrocarbons (PAHs)     laser multiphoton ionization/time-of-flight mass spectrometry (MPI/TOF-MS)    

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Transient imaging with a time-of-flight cameraand its applications

Jing-yu LIN, Ri-hui WU, Hong-man WANG, Ye-bin LIU

《信息与电子工程前沿（英文）》 2017年 第18卷 第9期   页码 1268-1276 doi: .org/10.1631/FITEE.1700556

摘要： Transient imaging is a technique in photography that recordsthe process of light propagation before it reaches a stationary statesuch that events at the light speed level can be observed. In thisreview we introduce three main models for transient imaging with atime-of-flight (ToF) camera: correlation model, frequency-domain model,and compressive sensing model. Transient imaging applications usuallyinvolve resolving the problem of light transport and separating thelight rays arriving along different paths. We discuss two of the applications:imaging objects inside scattering media and recovering both the shapeand texture of an object around a corner.

关键词： Transient imaging     Time-of-flight(ToF) camera     Scattering media     Around corners    

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采用飞行时间相机的瞬态成像及其应用

Jing-yu Lin, Ri-hui Wu, Hong-man Wang, Ye-bin Liu,jylin@gxu.edu.cn,liuyebin@tsinghua.edu.cn

《信息与电子工程前沿（英文）》 2017年 第18卷 第9期   页码 1268-1276 doi: 10.1631/FITEE.1700556

摘要： 介绍了采用飞行时间（time-of-flight, ToF）相机进行瞬态成像的三种数学模型，即相关函数模型、频域模型和压缩感知模型。瞬态图像应用主要基于光传输解析和不同光路光线分离。

关键词： 瞬态成像；飞行时间（time-of-flight     ToF）；散射介质；拐角遮挡    

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Identify the contribution of vehicle non-exhaust emissions: a single particle aerosol mass spectrometer

《环境科学与工程前沿（英文）》 2023年 第17卷 第5期 doi: 10.1007/s11783-023-1662-8

摘要：

● A single particle observation was conducted in a high traffic flow road environment.

关键词： Non-exhaust emissions     SPAMS     PMF     Roadside environment    

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Time of flight improved thermally grown oxide thickness measurement with terahertz spectroscopy

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0705-3

摘要： As a nondestructive testing technique, terahertz time-domain spectroscopy technology is commonly used to measure the thickness of ceramic coat in thermal barrier coatings (TBCs). However, the invisibility of ceramic/thermally grown oxide (TGO) reflective wave leads to the measurement failure of natural growth TGO whose thickness is below 10 μm in TBCs. To detect and monitor TGO in the emergence stage, a time of flight (TOF) improved TGO thickness measurement method is proposed. A simulative investigation on propagation characteristics of terahertz shows the linear relationship between TGO thickness and phase shift of feature wave. The accurate TOF increment could be acquired from wavelet soft threshold and cross-correlation function with negative effect reduction of environmental noise and system oscillation. Thus, the TGO thickness could be obtained efficiently from the TOF increment of the monitor area with different heating times. The averaged error of 1.61 μm in experimental results demonstrates the highly accurate and robust measurement of the proposed method, making it attractive for condition monitoring and life prediction of TBCs.

关键词： thermal barrier coatings     thermally grown oxide     terahertz spectroscopy     time of flight    

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Characteristics of mass distributions of aerosol particle and its inorganic water-soluble ions in summer

ZHAO Peng, ZHU Tong, LIANG Baosheng, HU Min, KANG Ling, GONG Jicheng

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 159-165 doi: 10.1007/s11783-007-0028-y

摘要： Agricultural activity is one of the most important sources of aerosol particles. To understand the mass distribution and sources of aerosol particles and their inorganic water-soluble ions in a suburb farmland of Beijing, particle samples were collected using a microorifice uniform deposit impactor (MOUDI) in the summer of 2004 in a suburb vegetable field. The distribution of the particles and their inorganic water-soluble ions in the diameter range of 0.18 18 mm were measured. The dominant fine particle ions were SO, NO, and NH. The association of day-to-day variation of the concentration of these ions with temperature, humidity, and solar radiation suggested that they are formed by the reaction of NH3 released from the vegetable field with the acid species produced from photochemical reactions. Fine particle K is likely from vegetation emission and biomass burning. Coarse particles like Ca, Mg, NO, and SO are suggested to come from the mechanical process by which the soil particle entered the atmosphere, and from the reaction of the acid species at the surface of the soil particle. The results show that fertilizer and soil are important factors determining the aerosol particle over agricultural fields, and vegetable fields in suburban Beijing contribute significantly to the aerosol particle.

关键词： diameter     atmosphere     suburban     contribute     agricultural    

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Modeling radiative effects of haze on summer-time convective precipitation over North China: a case study

Xuying WANG, Bin ZHANG

《环境科学与工程前沿（英文）》 2016年 第10卷 第4期 doi: 10.1007/s11783-016-0840-3

摘要： We modeled the impact of haze radiative effects on precipitation in North China. Shortwave heating induced by haze radiative effects would reduce heavy rainfalls. Convection was the key factor that whether precipitation was enhanced or suppressed. Precipitation was often suppressed where CAPE, RH and updraft velocities were high. The impact of haze radiative effect on summertime 24-h convective precipitation over North China was investigated using WRF model (version 3.3) through model sensitivity studies between scenarios with and without aerosol radiative effects. The haze radiative effect was represented by incorporating an idealized aerosol optical profile, with AOD values around 1, derived from the aircraft measurement into the WRF shortwave scheme. We found that the shortwave heating induced by aerosol radiative effects would significantly reduce heavy rainfalls, although its effect on the post-frontal localized thunderstorm precipitation was more diverse. To capture the key factors that determine whether precipitation is enhanced or suppressed, model grids with 24-h precipitation difference between the two scenarios exceeding certain threshold (>30 mm or<-30 mm) were separated into two sets. Analyses of key meteorological variables between the enhanced and suppressed regimes suggested that atmospheric convection was the most important factor that determined whether precipitation was enhanced or suppressed during summertime over North China. The convection was stronger over places with precipitation enhancement over 30 mm. Haze weakened the convection over places with precipitation suppression exceeding 30 mm and caused less water vapor to rise to a higher level and thus further suppressed precipitation. The suppression of precipitation was often accompanied with relatively high convective available potential energy (CAPE), relative humidity (RH) and updraft velocities.

关键词： Haze     Aerosol radiative effects     Convective precipitation    

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Review on the applications of Tropospheric Emissions Spectrometer to air-quality research: Perspectives

Yuxuan WANG, Yuqiang ZHANG, Jiming HAO,

《环境科学与工程前沿（英文）》 2010年 第4卷 第1期   页码 12-19 doi: 10.1007/s11783-010-0012-9

摘要： The Tropospheric Emissions Spectrometer (TES) aboard the National Aeronautics and Space Administration’s (NASA’s) Aura satellite launched in July 2004 is the first satellite instrument to provide simultaneous retrievals of ozone (O) and carbon monoxide (CO) throughout the Earth’s lower atmosphere. This paper briefly reviews the TES instrument, the retrieval of O and CO profiles, and the validation of the retrievals. The applications of TES O and CO products include mapping the vertical and horizontal distribution of tropospheric O and CO and their correlations, examining the regional and continental outflow, and analyzing the variability of the two species associated with certain weather and climatic conditions, such as El Niño and the Asian monsoon. TES retrievals of O and CO offer an important new source of satellite data over China with good spatial and temporal coverage that can provide evaluation and constraints on the performance of chemical transport models in simulating the general features of ozone pollution over China. Special observations have been conducted and requests may be submitted to the TES team to make geographically focused observations of O and CO over China.

关键词： Tropospheric Emissions Spectrometer (TES)     ozone     carbon monoxide     China    

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Air bearing center cross gap of neutron stress spectrometer sample table support system

Yang LI,Yunxin WU,Hai GONG,Xiaolei FENG

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 403-411 doi: 10.1007/s11465-016-0405-y

摘要：

A support system is the main load-bearing component of sample table for neutron stress spectrometer, and air bearing is an important element of a support system. The neutron stress spectrometer sample table was introduced, and the scheme for air bearing combination was selected. To study the performance of air bearing center cross gap, finite element models (FEMs) were established based on air motion and Reynolds equations, effects of air supply pressure, and gap parameters on the overturning moment and bearing capacity of air bearing center cross gap were analyzed. Results indicate that the width, depth, and height differences of the marble floor gap played important roles in the performance of the air bearing. When gap width is lesser than 1 mm and gap depth is lower than 0.4 mm, bearing capacity and overturning moment would vary rapidly with the variation of the width and depth. A gap height difference results in the bearing capacity dropping rapidly. The FEM results agree well with experimental results. Further, findings of the study could guide the design of the support system and marble floor.

关键词： neutron stress spectrometer     sample table     support system     air bearing     center cross gap     simulation     experiment    

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Multi-time scale dynamics in power electronics-dominated power systems

Xiaoming YUAN, Jiabing HU, Shijie CHENG

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 303-311 doi: 10.1007/s11465-017-0428-z

摘要：

Electric power infrastructure has recently undergone a comprehensive transformation from electromagnetics to semiconductors. Such a development is attributed to the rapid growth of power electronic converter applications in the load side to realize energy conservation and on the supply side for renewable generations and power transmissions using high voltage direct current transmission. This transformation has altered the fundamental mechanism of power system dynamics, which demands the establishment of a new theory for power system control and protection. This paper presents thoughts on a theoretical framework for the coming semiconducting power systems.

关键词： power electronics     power systems     multi-time scale dynamics     mass-spring-damping model     self-stabilizing and en-stabilizing property     multi-time scale power system stabilizer    

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Studies on the liquid-liquid interfacial mass transfer process using holographic interferometry

ZHAO Chaofan, ZHU Chunying, MA Youguang

《化学科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 1-4 doi: 10.1007/s11705-008-0006-3

摘要： This paper aims at the interfacial phenomena of liquid-liquid mass transfer and its characteristic. By using the real-time holographic technique, the concentration distributions on the aqueous side were obtained according to holographic diagrams of mass transfer of ethanol through the interface of oil and water at different initial concentrations. Furthermore, the concentrations near the interface and the mass transfer coefficients were attained. A correlation of concentration near the interface to the concentration of the solute in the oil side was proposed. An approach of interfacial energy with solute concentration was established, and the calculated results are at good agreement with the experimental data. It is indicated that the liquid-liquid mass transfer process is approximately in accordance with two-film theory, the interfacial performance may be changed by the addition of the solute, and the interface of liquid-liquid is non-equilibrium thermodynamically during the mass transfer process.

关键词： liquid-liquid     different     real-time holographic     addition     transfer    

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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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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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标题 作者 时间 类型 操作

Single particle analysis of ambient aerosols in Shanghai during the World Exposition, 2010: two case studies

Shikang TAO, Xinning WANG, Hong CHEN, Xin YANG, Mei LI, Lei LI, Zhen ZHOU

期刊论文

Characterization of submicron aerosols in the urban outflow of the central Pearl River Delta region of China

Zhaoheng GONG, Zijuan LAN, Lian XUE, Liwu ZENG, Lingyan HE, Xiaofeng HUANG

期刊论文

Determination of persistent organic pollutants by gas chromatography/laser multiphoton ionization/time-of-flightmass spectrometry

Osamu SHITAMICHI, Taiki MATSUI, Yamei HUI, Weiwei CHEN, Totaro IMASAKA

期刊论文

Transient imaging with a time-of-flight cameraand its applications

Jing-yu LIN, Ri-hui WU, Hong-man WANG, Ye-bin LIU

期刊论文

采用飞行时间相机的瞬态成像及其应用

Jing-yu Lin, Ri-hui Wu, Hong-man Wang, Ye-bin Liu,jylin@gxu.edu.cn,liuyebin@tsinghua.edu.cn

期刊论文

Identify the contribution of vehicle non-exhaust emissions: a single particle aerosol mass spectrometer

期刊论文

Time of flight improved thermally grown oxide thickness measurement with terahertz spectroscopy

期刊论文

Characteristics of mass distributions of aerosol particle and its inorganic water-soluble ions in summer

ZHAO Peng, ZHU Tong, LIANG Baosheng, HU Min, KANG Ling, GONG Jicheng

期刊论文

Modeling radiative effects of haze on summer-time convective precipitation over North China: a case study

Xuying WANG, Bin ZHANG

期刊论文

Review on the applications of Tropospheric Emissions Spectrometer to air-quality research: Perspectives

Yuxuan WANG, Yuqiang ZHANG, Jiming HAO,

期刊论文

Air bearing center cross gap of neutron stress spectrometer sample table support system

Yang LI,Yunxin WU,Hai GONG,Xiaolei FENG

期刊论文

Multi-time scale dynamics in power electronics-dominated power systems

Xiaoming YUAN, Jiabing HU, Shijie CHENG

期刊论文

Studies on the liquid-liquid interfacial mass transfer process using holographic interferometry

ZHAO Chaofan, ZHU Chunying, MA Youguang

期刊论文

Physical and chemical processes of wintertime secondary nitrate aerosol formation

Qi YING

期刊论文

Computational fluid dynamics simulation of aerosol transport and deposition

Yingjie TANG, Bing GUO

期刊论文