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| 1 | Relative Contributions of Boundary-Layer Meteorological Factors to the Explosive Growth of PM2.5 during the Red-Alert Heavy Pollution Episodes in Beijing in December 2016显示文摘Based on observations of urban mass concentration of fine particulate matter smaller than 2.5 μm in diameter(PM_(2.5)), ground meteorological data, vertical measurements of winds, temperature, and relative humidity(RH), and ECMWF reanalysis data, the major changes in the vertical structures of meteorological factors in the boundary layer(BL) during the heavy aerosol pollution episodes(HPEs) that occurred in winter 2016 in the urban Beijing area were analyzed. The HPEs are divided into two stages: the transport of pollutants under prevailing southerly winds, known as the transport stage(TS), and the PM_(2.5) explosive growth and pollution accumulation period characterized by a temperature inversion with low winds and high RH in the lower BL, known as the cumulative stage(CS). During the TS, a surface high lies south of Beijing, and pollutants are transported northwards. During the CS, a stable BL forms and is characterized by weak winds, temperature inversion, and moisture accumulation. Stable atmospheric stratification featured with light/calm winds and accumulated moisture(RH > 80%) below 250 m at the beginning of the CS is closely associated with the inversion, which is strengthened by the considerable decrease in near-surface air temperature due to the interaction between aerosols and radiation after the aerosol pollution occurs. A significant increase in the PLAM(Parameter Linking Aerosol Pollution and Meteorological Elements) index is found, which is linearly related to PM mass change. During the first 10 h of the CS, the more stable BL contributes approximately 84% of the explosive growth of PM_(2.5) mass. Additional accumulated near-surface moisture caused by the ground temperature decrease, weak turbulent diffusion, low BL height, and inhibited vertical mixing of water vapor is conducive to the secondary aerosol formation through chemical reactions, including liquid phase and heterogeneous reactions, which further increases the PM_(2.5) concentration levels. The contribution of these reaction mechanisms to the explosive growth of PM_(2.5) mass during the early CS and subsequent pollution accumulation requires further investigation. | junting zhong xiaoye zhang yaqiang wang junying sun yangmei zhang jizhi wang kaiyan tan xiaojing shen haochi che lu zhang zhouxiang zhang xuefei qi huarong zhao sanxue ren yang li | 2017 | Journal of Meteorological Research2017，31，5： | 25 |
| 2 | Aerosol Hygroscopicity during the Haze Red-Alert Period in December 2016 at a Rural Site of the North China Plain显示文摘A humidification system was deployed to measure aerosol hygroscopicity at a rural site of the North China Plain during the haze red-alert period 17–22 December 2016. The aerosol scattering coefficients under dry [relative humidity(RH) < 30%] and wet(RH in the range of 40%–85%) conditions were simultaneously measured at wavelengths of450, 550, and 700 nm. It is found that the aerosol scattering coefficient and backscattering coefficient increased by only 29% and 10%, respectively when RH went up from 40% to 80%, while the hemispheric backscatter fraction went down by 14%, implying that the aerosol hygroscopicity represented by the aerosol scattering enhancement factor f(RH) is relatively low and RH exerted little effects on the aerosol light scattering in this case. The scattering enhancement factors do not show significant differences at the three wavelengths, only with an approximate 2% variation, suggesting that the aerosol hygroscopicity is independent of the wavelength. Aerosol hygroscopicity is highly dependent on the aerosol chemical composition. When there is a large mass fraction of inorganics and a small mass fraction of organic matter, f(RH) reaches a high value. The fraction of NO_3^- was strongly correlated with the aerosol scattering coefficient at RH = 80%, which suggests that NO_3^- played an important role in aerosol hygroscopic growth during the heavy pollution period. | Xuefei QI Junying SUN Lu ZHANG Xiaojing SHEN Xiaoye ZHANG Yangmei ZHANG Yaqiang WANG Haochi CHE Zhouxiang ZHANG Junting ZHONG Kaiyan TAN Huarong ZHAO Sanxue REN | 2018 | Journal of Meteorological Research2018，32，1： | 7 |
| 3 | Comparison of Submicron Particles at a Rural and an Urban Site in the North China Plain during the December 2016 Heavy Pollution Episodes显示文摘An extensive field experiment for measurement of physical and chemical properties of aerosols was conducted at an urban site in the Chinese Academy of Meteorological Sciences(CAMS) in Beijing and at a rural site in Gucheng(GC), Hebei Province in December 2016. This paper compares the number size distribution of submicron particle matter(PM1, diameter < 1 μm) between the two sites. The results show that the mean PM1 number concentration at GC was twice that at CAMS, and the mass concentration was three times the amount at CAMS. It is found that the accumulation mode(100–850 nm) particles constituted the largest fraction of PM1 at GC, which was significantly correlated with the local coal combustion, as confirmed by a significant relationship between the accumulation mode and the absorption coefficient of soot particles. The high PM1 concentration at GC prevented the occurrence of new particle formation(NPF) events, while eight such events were observed at CAMS. During the NPF events, the mass fraction of sulfate increased significantly, indicating that sulfate played an important role in NPF. The contribution of regional transport to PM1 mass concentration was approximately 50% at both sites, same as that of the local emission. However, during the red-alert period when emission control took place, the contribution of regional transport was notably higher. | Xiaojing SHEN Junying SUN Xiaoye ZHANG Yangmei ZHANG Yaqiang WANG Kaiyan TAN Peng WANG Lu ZHANG Xuefei QI Haochi CHE Zhouxiang ZHANG Junting ZHONG Huarong ZHAO Sanxue REN | 2018 | Journal of Meteorological Research2018，32，1： | 2 |
| 4 | Changes in Typhoon Regional Heavy Precipitation Events over China from 1960 to 2018显示文摘In earlier studies,objective techniques have been used to determine the contribution of tropical cyclones to precipitation(TCP)in a region,where the Tropical cyclone Precipitation Event(TPE)and the Regional Heavy Precipitation Events(RHPEs)are defined and investigated.In this study,TPE and RHPEs are combined to determine the Typhoon Regional Heavy Precipitation Events(TRHPEs),which is employed to evaluate the contribution of tropical cyclones to regional extreme precipitation events.Based on the Objective Identification Technique for Regional Extreme Events(OITREE)and the Objective Synoptic Analysis Technique(OSAT)to define TPE,temporal and spatial overlap indices are developed to identify the combined events as TRHPE.With daily precipitation data and TC best-track data over the western North Pacific from 1960 to 2018,86 TRHPEs have been identified.TRHPEs contribute as much as 20%of the RHPEs,but100%of events with extreme individual precipitation intensities.The major TRHPEs continued for approximately a week after tropical cyclone landfall,indicating a role of post landfall precipitation.The frequency and extreme intensity of TRHPEs display increasing trends,consistent with an observed positive trend in the mean intensity of TPEs as measured by the number of daily station precipitation observations exceeding 100 mm and 250 mm.More frequent landfalling Southeast and South China TCs induced more serious impacts in coastal areas in the Southeast and the South during 1990-2018 than1960-89.The roles of cyclone translation speed and'shifts'in cyclone tracks are examined as possible explanations for the temporal trends. | Yangmei TIAN John LMCBRIDE Fumin REN Guoping LI Tian FENG | 2022 | Advances in Atmospheric Sciences2022，39，2： | 1 |
| 5 | Multifunctional metal-polyphenol nanocomposite for melanoma targeted photo/chemodynamic synergistic therapy显示文摘Due to the hypoxic state of the tumor microenvironment(TME),photodynamic therapy(PDT)suffers from insufficient ROS production.The metal-polyphenol network-mediated Fenton reaction can generate reac-tive oxygen species(ROS)by consuming H_(2)O_(2) in TME,improving the inadequate ROS generation problem of PDT.Therefore,synergistic therapy combining PDT and Fenton response-based CDT is a promising ap-proach for cancer treatment.Herein,a metal-polyphenol nanocomposite was deposited with gallic acid grafted hyaluronic acid and Fe^(3+) to contrast a Ce6 nano-delivery system(Ce6@HSF NPs)for melanoma synergistic therapy.Ce6@HSF NPs could be used as a Fenton reagent to induce the·OH production and enhance the PDT effect of Ce6 to a certain extent.After 4 h of cellular uptake,the fluorescence intensity of Ce6 in the Ce6@HSF NPs group was higher than 3 times that in the Ce6 group.The intracellular ROS generation level of the Ce6@HSF NPs(L)group combining CDT and PDT was higher than that of the Ce6 group and Ce6@HSF NPs group.In vitro and in vivo anti-melanoma studies show that Ce6@HSF NPs(L)group exhibited better anti-melanoma than other groups.Together,Ce6@HSF NPs provide a promising synergistic treatment potential for melanoma. | Di Chuan Huan Hou Yuelong Wang Min Mu Jinglun Li Yangmei Ren Na Zhao Bo Han Haifeng Chen Gang Guo | 2023 | Journal of Materials Science & Technology2023，，21： | 0 |
| 6 | Polydopamine-coated i-motif DNA/Gold nanoplatforms for synergistic photothermal-chemotherapy显示文摘The combination of photothermal therapywith chemotherapy has gradually developed into promising cancer therapy.Here,a synergistic photothermal-chemotherapy nanoplatform based on polydopamine(PDA)-coated gold nanoparticles(AuNPs)were facilely achieved via the in situ polymerization of dopamine(DA)on the surface of AuNPs.This nanoplatform exhibited augmented photothermal conversion efficiency and enhanced colloidal stability in comparison with uncoated PDA shell AuNPs.The i-motif DNA nanostructure was assembled on PDA-coated AuNPs,which could be transformed into a C-quadruplex structure under an acidic environment,showing a characteristic pH response.The PDA shell served as a linker between the AuNPs and the i-motif DNA nanostructure.To enhance the specific cellular uptake,the AS1411 aptamer was introduced to the DNA nanostructure employed as a targeting ligand.In addition,Dox-loaded NPs(DAu@PDA-AS141)showed the pH/photothermal-responsive release of Dox.The photothermal effect of DAu@PDA-AS141 elicited excellent photothermal performance and efficient cancer cell inhibition under 808 nm near-infrared(NIR)irradiation.Overall,these results demonstrate that the DAu@PDA-AS141 nanoplatform shows great potential in synergistic photothermal-chemotherapy. | Bo Chen Lan Mei Rangrang Fan Di Chuan Yangmei Ren Min Mu Haifeng Chen Bingwen Zou Gang Guo | 2023 | Asian Journal of Pharmaceutical Sciences2023，18，2： | 0 |
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