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168篇 您的检索式:作者名="Jiming Liu"
    题名 作者 年代 出处 被引量
1复杂网络聚类方法显示文摘网络簇结构是复杂网络最普遍和最重要的拓扑属性之一,具有同簇节点相互连接密集、异簇节点相互连接稀疏的特点.揭示网络簇结构的复杂网络聚类方法对分析复杂网络拓扑结构、理解其功能、发现其隐含模式、预测其行为都具有十分重要的理论意义,在社会网、生物网和万维网中具有广泛应用.综述了复杂网络聚类方法的研究背景、研究意义、国内外研究现状以及目前所面临的主要问题,试图为这个新兴的研究方向勾画出一个较为全面和清晰的概貌,为复杂网络分析、数据挖掘、智能Web、生物信息学等相关领域的研究者提供有益的参考.杨博 刘大有 LIU Jiming 金弟 马海宾 2009软件学报2009,20,1:206
2Contrasting trends of PM2.5 and surface-ozone concentrations in China from 2013 to 2017显示文摘Although much attention has been paid to investigating and controlling air pollution in China,the trends of air-pollutant concentrations on a national scale have remained unclear.Here,we quantitatively investigated the variation of air pollutants in China using long-term comprehensive data sets from 2013 to 2017,during which Chinese government made major efforts to reduce anthropogenic emission in polluted regions.Our results show a significant decreasing trend in the PM2.5 concentration in heavily polluted regions of eastern China,with an annual decrease of〜7%compared with measurements in 2013.The measured decreased concentrations of SO2>NO2 and CO(a proxy for anthropogenic volatile organic compounds)could explain a large fraction of the decreased PM2.5 concentrations in different regions.As a consequence;the heavily polluted days decreased significantly in corresponding regions.Concentrations of organic aerosol;nitrate;sulfate,ammonium and chloride measured in urban Beijing revealed a remarkable reduction from 2013 to 2017;connecting the decreases in aerosol precursors with corresponding chemical components closely.However;surface-ozone concentrations showed increasing trends in most urban stations from 2013 to 2017;which indicates stronger photochemical pollution.The boundary-layer height in capital c让ies of eastern China showed no significant trends over the Beijing-Tianjin-Hebei,Yangtze River Delta and Pearl River Delta regions from 2013 to 2017;which confirmed the reduction in anthropogenic emissions.Our results demonstrated that the Chinese government was successful in the reduction of particulate matter in urban areas from 2013 to 2017,although the ozone concentration has increased significantly;suggesting a more complex mechanism of improving Chinese air quality in the future.Yonghong Wang Wenkang Gao Shuai Wang Tao Song Zhengyu Gong Dongsheng Ji Lili Wang Zirui Liu Guiqian Tang Yanfeng Huo Shili Tian Jiayun Li Mingge Li Yuan Yang Biwu Chu Tuukka Petaja Veli-Matti Kerminen Hong He Jiming Hao Markku Kulmala Yuesi Wang Yuanhang Zhang 2020National Science Review2020,7,8:51
3Trends in particulate matter and its chemical compositions in China from 2013–2017显示文摘Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in evaluating the rationality of environmental air quality control strategies.Based on the sampling and chemical composition data of PM2.5 in different key regions of China in the CARE-China observation network,this research analyzes the environmental air quality data released by the China National Environmental Monitoring Centre during the studied period to determine the changes in the particulate matter mass concentration in key regions and the evolution of the corresponding chemical compositions during the implementation of the Action Plan for Prevention and Control of Air Pollution from 2013-2017.The results show the following.(1)The particulate matter mass concentration in China showed a significant downward trend;however,the PM2.5 annual mass concentration in 64%of cities exceeds the New Chinese Ambient Air Quality Standard(CAAQS)GradeⅡ(GB3095-2012).The region to the east of the Taihang Mountains,the Fenhe and Weihe River Plain and the Urumqi-Changji regions in Xinjiang,all have PM2.5 concentration loading that is still high,and heavy haze pollution occurred frequently in the autumn and winter.(2)During the heavy pollution in the autumn and winter,the concentrations of sulfate and organic components decreased significantly.The mean SO42-concentration in PM2.5 decreased by 76%,12%,81%and 38%in Beijing-Tianjin-Hebei(BTH),the Pearl River Delta(PRD),the Sichuan-Chongqing region(SC)and the Fenhe and Weihe River Plain,respectively.The mean organic matter(OM)concentration decreased by 70%,44%,48%and 31%,respectively,and the mean concentration of NH4+decreased by 68%,1.6%,38%and 25%,respectively.The mean elemental carbon(EC)concentration decreased by 84%and 20%in BTH and SC,respectively,and it increased by 61%and 11%in the PRD and Fenhe and Weihe River Plain,respectively.The mean concentration of mineral and unresolved chemical components(MI)dropped by 70%,24%and 13%in BTH,the PRD and the Fenhe and Weihe River Plain,respectively.The change in the PM2.5 chemical composition is consistent with the decrease of the PM2.5mass concentration.(3)In 2015,the mean OM concentration contributions to fine particles and coarse particles were 13-46%and 46-57%,respectively,and the mean MI concentration contributions to fine particles and coarse and particles were 31-60%and 39-73%,respectively;these values are lower than the 2013 values from the key regions,which is the most important factor behind the decrease of the particulate matter mass concentration.From 2013 to 2015,among the chemical components of different particle size fractions,the peak value of the coarse particle size fraction decreased significantly,and the fine particle size fractions of SO42-,NO3-,and NH4+decreased with the decrease of the particulate matter mass concentration in different particle size fractions.The fine-particle size peaks of SO42-,NO3-and NH4+shifted from 0.65-1.1μm to the finer size range of0.43-0.65μm during the same time frame.Yuesi WANG Wenjie LI Wenkang GAO Zirui LIU Shili TIAN Rongrong SHEN Dongsheng JI Shuai WANG Lili WANG Guiqian TANG Tao SONG Mengtian CHENG Gehui WANG Zhengyu GONG Jiming HAO Yuanhang ZHANG 2019Science China Earth Sciences2019,62,12:23
4Vehicular volatile organic compounds losses due to refueling and diurnal process in China: 2010–2050显示文摘Volatile organic compounds(VOCs) are crucial to control air pollution in major Chinese cities since VOCs are the dominant factor influencing ambient ozone level, and also an important precursor of secondary organic aerosols. Vehicular evaporative emissions have become a major and growing source of VOC emissions in China. This study consists of lab tests, technology evaluation, emissions modeling, policy projections and cost-benefit analysis to draw a roadmap for China for controlling vehicular evaporative emissions. The analysis suggests that evaporative VOC emissions from China's light-duty gasoline vehicles were approximately 185,000 ton in 2010 and would peak at 1,200,000 ton in 2040 without control. The current control strategy implemented in China, as shown in business as usual(BAU) scenario, will barely reduce the long-term growth in emissions. Even if Stage II gasoline station vapor control policies were extended national wide(BAU + extended Stage II), there would still be over 400,000 ton fuel loss in 2050. In contrast, the implementation of on-board refueling vapor recovery(ORVR) on new cars could reduce 97.5% of evaporative VOCs by 2050(BAU + ORVR/BAU + delayed ORVR). According to the results, a combined Stage II and ORVR program is a comprehensive solution that provides both short-term and long-term benefits. The net cost to achieve the optimal total evaporative VOC control is approximately 62 billion CNY in 2025 and 149 billion CNY in 2050.Xiaofan Yang Huan Liu Hongyang Cui Hanyang Man Mingliang Fu Jiming Hao Kebin He 2015Journal of Environmental Sciences2015,27,7:19
5Epidemiological and risk analysis of the H7N9 subtype influenza outbreak in China at its early stage显示文摘Dozens of human cases infected with H7N9 subtype avian influenza virus (AIV) have been confirmed in China since March, 2013. Distribution data of sexes, ages, professions and regions of the cases were analyzed in this report. The results showed that the elderly cases, especially the male elderly, were significantly more than expected, which is different from human cases of H5N1 avian influenza and human cases of the pandemic H1N1 influenza. The outbreak was rated as a Grade Ⅲ (severe) outbreak, and it would evolve into a Grade IV (very severe) outbreak soon, using a method reported previously. The H7N9 AIV will probably circulate in humans, birds and pigs for years. Moreover, with the driving force of natural selection, the virus will probably evolve into highly pathogenic AIV in birds, and into a deadly pandemic influenza virus in humans. Therefore, the H7N9 outbreak has been assumed severe, and it is likely to become very or extremely severe in the future, highlighting the emergent need of forceful scientific measures to eliminate any infected animal flocks. We also described two possible mild scenarios of the future evolution of the outbreak.ZHUANG QingYe WANG SuChun WU MeiLi LIU Shuo JIANG WenMing HOU GuangYu LI JinPing WANG KaiCheng YU JianMin CHEN JiMing CHEN JiWang 2013Chinese Science Bulletin2013,58,26:18
6Rapid improvement of PM2.5 pollution and associated health benefits in China during 2013–2017显示文摘Exposure to fine particulate matter(PM2.5)is known to harm public health.In China,after implementation of aggressive emissions control measures under the Action Plan of Air Pollution Prevention and Control(2013-2017),air quality has significantly improved.In this work,we investigated changes in PM2.5 exposure and the associated health impacts in China for the period 2013-2017.We used an optimal estimator of PM2.5 combining in-situ observations,satellite measurements,and simulations from a chemical transport model to derive the spatial and temporal variations in PM2.5 exposure,and then used welldeveloped exposure-response functions to estimate the premature deaths attributable to PM2.5 exposure.We found that national population-weighed annual mean PM2.5 concentrations decreased from 67.4μgm-3 in 2013 to 45.5μgm-3 in 2017(32%reduction).This rapid decrease in PM2.5 pollution led to a 14%reduction in premature deaths due to long-term exposure.We estimated that,during 2013-2017,the premature deaths attributable to long-term PM2.5 exposure decreased from 1.2 million(95%CI:1.0,1.3;fraction of total mortality:13%)in 2013 to 1.0 million(95%CI:0.9,1.2;10%)in 2017.Despite the rapid decrease in annual mean PM2.5 concentrations,health benefits associated with reduced long-term exposure were limited,because for many cities,the PM2.5 levels remain at the portion where the exposure-response function is less steeper than that at the lowconcentration end.We also found that the deaths associated with acute exposure decreased by 61%during 2013-2017 due to rapid reduction in the number of heavily polluted days.Our results confirm that clean air policies in China have mitigated the air pollution crisis;however,continuous emissions reduction efforts are required to protect citizens from air pollution.Tao XUE Jun LIU Qiang ZHANG Guannan GENG Yixuan ZHENG Dan TONG Zhu LIU Dabo GUAN Yu BO Tong ZHU Kebin HE Jiming HAO 2019Science China Earth Sciences2019,62,12:17
7PandaX: a liquid xenon dark matter experiment at CJPL显示文摘PandaX is a large liquid-xenon detector experiment usable for direct dark-matter detection and 136Xe double-beta decay search.The central vessel was designed to accommodate a staged target volume increase from initially 120 kg(stage I)to 0.5 t(stage II)and eventually to a multi-ton scale.The experiment is located in the Jinping Deep-Underground Laboratory in Sichuan,China.The detector operates in dual-phase mode,allowing detection of both prompt scintillation,and ionization charge through proportional scintillation.In this paper a detailed description of the stage I detector design and performance as well as results established during the commissioning phase are presented.CAO XiGuang CHEN Xun CHEN YunHua CUI XiangYi FANG DeQing FU ChangBo GIBONI Karl L. GONG HaoWei GUO GuoDong HE Ming HU Jie HUANG XingTao JI XiangDong JU YongLin LI ShaoLi LIN Qing LIU HuaXuan LIU JiangLai LIU Xiang LORENZON Wolfgang MA YuGang MAO YaJun NI KaiXuan PUSHKIN Kirill REN XiangXiang SCHUBNELL Michael SHEN ManBing SHI YuJie STEPHENSON Scott TAN AnDi TARLé Greg WANG HongWei WANG JiMing WANG Meng WANG XuMing WANG Zhou WEI YueHuan WU ShiYong XIAO MengJiao XIAO Xiang XIE PengWei YE Tao YOU YingHui ZEN XiongHui ZHANG Hua ZHANG Tao ZHAO HaiYing ZHAO Li ZHOU XiaoPeng ZHU ZhongHua 2014Science China(Physics,Mechanics & Astronomy)2014,57,8:9
8Inferring the potential risks of H7N9 infection by spatiotemporally characterizing bird migration and poultry distribution in eastern China显示文摘Background:In view of the rapid geographic spread and the increasing number of confirmed cases of novel influenza A(H7N9)virus infections in eastern China,we developed a diffusion model to spatiotemporally characterize the impacts of bird migration and poultry distribution on the geographic spread of H7N9 infection.Methods:Three types of infection risks were estimated for 12 weeks,from February 4 to April 28,2013,including(i)the risk caused by bird migration,(ii)the risk caused by poultry distribution,and(iii)the integrated risk caused by both bird migration and poultry distribution.To achieve this,we first developed a method for estimating the likelihood of bird migration based on available environmental and meteorological data.Then,we adopted a computational mobility model to estimate poultry distribution based on annual poultry production and consumption of each province/municipality.Finally,the spatiotemporal risk maps were created based on the integrated impacts of both bird migration and poultry distribution.Results:In the study of risk estimation caused by bird migration,the likelihood matrix was estimated based on the 7-day temperature,from February 4 to April 28,2013.It was found the estimated migrant birds mainly appear in the southeastern provinces of Zhejiang,Shanghai and Jiangsu during Weeks 1 to 4,and Week 6,followed by appearing in central eastern provinces of Shandong,Hebei,Beijing,and Tianjin during Weeks 7 to 9,and finally in northeastern provinces of Liaoning,Jilin,and Heilongjiang during Weeks 10 to 12.In the study of risk caused by poultry distribution,poultry distribution matrix was created to show the probability of poultry distribution.In spite of the fact that the majority of the initial infections were reported in Shanghai and Jiangsu,the relative risk of H7N9 infection estimated based on the poultry distribution model predicted that Jiangsu may have a slightly higher likelihood of H7N9 infection than those in Zhejiang and Shanghai,if we only take the probability of poultry distribution into consideration.In the study of integrated risk caused by both bird migration and poultry distribution,the higher risk in southeastern provinces occurred during the first 8 weeks,and that in central eastern provinces appeared during Weeks 8 to 12,and that in northeastern provinces since Week 12.Therefore,it is necessary to regulate the poultry markets as long as the poultry-to-poultry transmission is not so well understood.Conclusion:With reference to the reported infection cases,the demonstrated risk mapping results will provide guidance in active surveillance and control of human H7N9 infections by taking intensive intervention in poultry markets.Benyun Shi Shang Xia Guo-Jing Yang Xiao-Nong Zhou Jiming Liu 2013Infectious Diseases of Poverty2013,2,1:8
9Numerical Study on Flow-induced Noise for a Steam Stop-valve Using Large Eddy Simulation显示文摘噪音在 250Jiming Liu Tao Zhang Yong'ou Zhang 2013Journal of Marine Science and Application2013,12,3:8
10Role of ammonia in forming secondary aerosols from gasoline vehicle exhaust显示文摘Ammonia(NH3) plays vital roles in new particle formation and atmospheric chemistry. Although previous studies have revealed that it also influences the formation of secondary organic aerosols(SOA) from ozonolysis of biogenic and anthropogenic volatile organic compounds(VOCs), the influence of NH3 on particle formation from complex mixtures such as vehicle exhausts is still poorly understood. Here we directly introduced gasoline vehicles exhausts(GVE) into a smog chamber with NH3 absorbed by denuders to examine the role of NH3 in particle formation from GVE. We found that removing NH3 from GVE would greatly suppress the formation and growth of particles. Adding NH3 into the reactor after 3 h photo-oxidation of GVE, the particle number concentration and mass concentrations jumped explosively to much higher levels, indicating that the numbers and mass of particles might be enhanced when aged vehicle exhausts are transported to rural areas and mixed with NH3-rich plumes. We also found that the presence of NH3 had no significant influence on SOA formation from GVE. Very similar oxygen to carbon(O:C) and hydrogen to carbon(H:C) ratios resolved by aerosol mass spectrometer with and without NH3 indicated that the presence of NH3 also had no impact on the average carbon oxidation state of SOA from GVE.Tengyu Liu Xinming Wang Wei Deng Yanli Zhang Biwu Chu Xiang Ding Qihou Hu Hong He Jiming Hao 2015Science China Chemistry2015,58,9:7
11Polymorphisms of chemokine receptors and its ligand alleles influencing genetic suscepti-bity to HIV-1 infection in eight ethnic groups in Chinese mainland显示文摘Limited genetic information is available concerning the polymorphisms of HIV-1 resistant genes in indigenous Chinese populations. The aim of this study is to identify the allelic frequencies of the chemokine and chemokine receptor genes in the Chinese mainland. Genomic DNA samples extracted from whole blood of 2318 subjects were analyzed by using PCR or PCR/restriction fragment length polymorphism (RFLP) assays, and further confirmed by direct DNA sequencing. Higher frequencies of mutant CCR2-64I (19.15%-28.79%) and SDF1-3’A (19.10% -29.86%) alleles were found in subjects of 8 ethnic groups in the Chinese mainland. In contrast, the △32 mutation in CCRS gene occurs at a very low frequency (0.0016, n=1287) in Han population. A relatively high frequency of CCR5-wt/△32 heterozygotes was observed in Uygurian and Mongolian populations. No A32 mutation allele was detected in Tibetan and other 4 ethnic groups in Yunnan Province. There was no CCR5-m303 mutation in subjects of any ethnic group in the ChineseWANG Fusheng JIN lei LIU Mingxu HONG Weiguo SHI Hong LEI Zhouyun WANG Jiming DU Qingyou HOU Jing ZHANG Bing JIANG Jiandong WANG Yue LI Yueqi XU Anlong HUANG Honglian LIU Fajun 2001Chinese Science Bulletin2001,46,12:6
122019年度大气科学领域项目评审与研究成果分析显示文摘2018年6月,第八届国家自然科学基金委员会(以下简称自然科学基金委)第一次全体委员会议审议通过了新时代基金深化改革的总体目标和改革思路,通过确立基于“鼓励探索、突出原创;聚焦前沿、独辟蹊径;需求牵引、突破瓶颈;共性导向、交叉融通”4类科学问题属性分类的资助导向。“大气科学”学科被列为而上项冃分类评审试点改革学科。因此,大气学科处2019年的分类评审工作主要以“落实资助导向、推动精准资助”为总体思路,以鼓励和支持原创性、交叉性的科学研究,扶持薄弱学科.促进各学科均衡、协调和可持续发展为原则.开展相关工作。李积明 刘哲 郭郁葱 彭怡然 闻新宇 Li Jiming Liu Zhe Guo Yucong Peng Yiran Wen Xinyu 2019地球科学进展2019,34,11:5
13VOCs evaporative emissions from vehicles in China:Species characteristics of different emission processes显示文摘Vehicle evaporation is an essential source of VOCs in cities but is not well understood in China.Reported emission factors from previous studies are not enough for understanding the atmospheric chemical process of vehicular evaporative VOCs.In this work,a serious of detailed VOCs speciation profiles are developed based on test processes and emission processes.A mass balance method was used to divide different emission processes during diurnal tests.The results show that headspace vapor of gasoline cannot represent the real-world vehicle evaporation because of the significant differences in VOCs speciation profiles,especially for aromatics.To further distinguish emissions from evaporation and exhaust,only the ratios of MTBE/benzene and MTBE/toluene can serve as indicators when considering species from all evaporative processes.Besides,emissions from different sources change significantly with the seasons.To solve these problems,we developed a monthly comprehensive evaporation speciation profile.The individual profiles at the emission processes are weighted by the emission of the in-use vehicle fleet in Beijing to derive the comprehensive speciation profile of evaporative VOCs.Ozone formation potential(OFP)and secondary organic aerosol potential(SOAP)were used to evaluate the environmental impact.For SOAP,100 g evaporative emissions are equal to 6.05-12.71 g toluene in different months,much higher than that given using headspace vapors,especially in winter(7.2 times higher in December).These findings would improve our understanding of the evaporative VOCs emissions in China and their environmental impacts(e.g.,O3 and SOA formation).Hanyang Man Huan Liu He Niu Kai Wang Fanyuan Deng Xiaotong Wang Qian Xiao Jiming Hao 2020Environmental Science and Ecotechnology2020,,1:4
14Microclimatic characteristics of the Heihe oasis in the hyperarid zone of China显示文摘The microclimate of a desert oasis in hyperarid zone of China was monitored using micrometeorological methods and compared with those of areas adjacent to forested land. Differences in ground-level photosynthetically active radiation (PAR) on clear, cloudy and dust storm days and their subtending causes are analysed and discussed. Desert oases serve the ecological functions of altering solar radiation, adjusting near-ground and land surface temperatures, reducing soil temperature differences, lowering wind velocity, and increasing soil and atmospheric humidity. The total solar radiation in the interior of the oasis was roughly half of that outside a forest canopy. During the growing season, air temperatures in Populus euphratica Oliv. (poplar) and Tamarix ramosissima Ledeb. (tamarisk) forests were 1.62 °C and 0.83 °C lower respectively than those in the areas around the forests. Furthermore, the taller the forest cover, the greater the temperature drops; air temperatures in the upper storey were greater than those in the lower storey, i.e., air temperature rose with increasing height. Over the growing season, the relative humidities of the air in the poplar and tamarisk forests were 8.5% and 4.2% higher respectively than those in areas around the forests. Mean wind velocity in poplar-forested lands was 0.33 m s-1, 2.31 m s-1 lower than that in the surrounding area. During dust storm days the PAR was significantly lower than that on cloudy or clear days, when it was high and varied in an irregular manner.FENG Qi SI Jianhua ZHANG Yanwu YAO Jiming LIU Wei SU Yonghong 2006Journal of Geographical Sciences2006,16,1:4
15Estimating the effects of meteorology on PM_(2.5) reduction during the 2008 Summer Olympic Games in Beijing, China显示文摘Particulate pollution was a critical challenge to the promise of good air quality during the 2008 Beijing Olympic Games,which took place from August 8th to 24th.To ensure good air quality for the Games,several temporary emission control measures were implemented in Beijing and surrounding areas.Ambient particulate matter concentration decreased significantly during the Olympic period;however,it is difficult to distinguish the effectiveness of those control measures since meteorology also affects ambient PM_(2.5) concentration.In this work,a multiple linear regression model based on continuous field monitoring at a roadside site was conducted to evaluate the effects of meteorology and emission control measures on the reduction of PM_(2.5) during the 2008 Olympic Games.The hourly data set was divided into two time periods,the no control period,June 22nd to July 4th,and the control period,July 28th to August 21st.The response variable was PM_(2.5) and the meteorology covariates used in the model were hourly temperature,dew point temperature,wind speed and precipitation.Wind direction was not a significant predictor of PM_(2.5) levels in either the control or the no control period.Using the meteorologically-based regression coefficients from the two time periods,meteorology was found to contribute to at least a 16%reduction in PM_(2.5) levels in the roadside microenvironment;while the pollution control measures contributed to at least a 43%reduction in PM_(2.5) levels.Liu YANG Ye WU Jerry M.DAVIS Jiming HAO 2011Frontiers of Environmental Science & Engineering2011,5,3:4
16Overview of the Research and Development for Reduced Activation Ferritic/Martensitic Steel CLF-1显示文摘WANG Pinghuai XU Zengyu CHEN Jiming LIU Shi LI Xiongwei 2006Southwestern Institute of Physics Annual Report2006,,1:3
17Secondary aerosol formation and oxidation capacity in photooxidation in the presence of Al_2O_3 seed particles and SO_2显示文摘To investigate the sensitivity of secondary aerosol formation and oxidation capacity to NOx in homogeneous and heterogeneous reactions, a series of irradiated toluene/NOx/air and ?-pinene/NOx/air experiments were conducted in smog chambers in the absence or presence of Al2O3 seed particles. Various concentrations of NOx and volatile organic compounds(VOCs) were designed to simulate secondary aerosol formation under different scenarios for NOx. Under 'VOC-limited' conditions, the increasing NOx concentration suppressed secondary aerosol formation, while the increasing toluene concentration not only contributed to the increase in secondary aerosol formation, but also led to the elevated oxidation degree for the organic aerosol. Sulfate formation was suppressed with the increasing NOx due to a decreased oxidation capacity of the photooxidation system. Secondary organic aerosol(SOA) formation also decreased with the presence of high concentration of NOx, because organo-peroxy radicals(RO2) react with NOx instead of with peroxy radicals(RO2 or HO2), resulting in the formation of volatile organic products. The increasing concentration of NOx enhanced the formation of sulfate, nitrate and SOA under 'NOx-limited' conditions, in which the heterogeneous reactions played an important role. In the presence of Al2O3 seed particles, a synergetic promoting effect of mineral dust and NOx on secondary aerosol formation in heterogeneous reactions was observed in the photooxidation. This synergetic effect strengthened the positive relationship between NOx and secondary aerosol formation under 'NOx-limited' conditions but weakened or even overturned the negative relationship between NOx and secondary aerosol formation under 'VOC-limited' conditions. Sensitivity of secondary aerosol formation to NOx seemed different in homogeneous and heterogeneous reactions, and should be both taken into account in the sensitivity study. The sensitivity of secondary aerosol formation to NOx was further investigated under 'winter-like' and NH3-rich conditions. No obvious difference for the sensitivity of secondary aerosol formation except nitrate to NOx was observed.Biwu Chu Tengyu Liu Xiao Zhang Yongchun Liu Qingxin Ma Jinzhu Ma Hong He Xinming Wang Junhua Li Jiming Hao 2015Science China Chemistry2015,58,9:3
18Fine particulate matter(PM_(2.5)/PM_(1.0)) in Beijing,China: Variations and chemical compositions as well as sources显示文摘Particulate matter(i.e.,PM_(1.0) and PM_(2.5)),considered as the key atmospheric pollutants,exerts negative effects on visibility,global climate,and human health by associated chemical compositions.However,our understanding of PM and its chemical compositions in Beijing under the current atmospheric environment is still not complete after witnessing marked alleviation during 2013–2017.Continuous measurements can be crucial for further air quality improvement by better characterizing PM pollution and chemical compositions in Beijing.Here,we conducted simultaneous measurements on PM in Beijing during 2018–2019.Results indicate that annualmean PM_(1.0) and PM_(2.5) concentrations were 35.49±18.61μg/m^(3) and 66.58±60.17μg/m^(3),showing a positive response to emission controls.The contribution of sulfate,nitrate,and ammonium(SNA)played an enhanced role with elevated PM loading and acted as the main contributors to pollution episodes.Discrepancies observed among chemical species between PM_(1.0) and PM_(2.5) in spring suggest that sand particles trend to accumulate in the range of 1–2.5μm.Pollution episodes occurred accompanied with southerly clusters and high formation of SNA by heterogeneous reactions in summer and winter,respectively.Results from positive matrix factorization(PMF)combined with potential source contribution function(PSCF)models showed that potential areas were seasonal dependent,secondary and vehicular sources became much more important compared with previous studies in Beijing.Our study presented a continuous investigation on PM and sources origins in Beijing,which provides a better understanding for further emission control as well as a reference for other cities in developing countries.Lining Luo Xiaoxuan Bai Shuhan Liu Bobo Wu Wei Liu Yunqian Lv Zhihui Guo Shumin Lin Shuang Zhao Yan Hao Jiming Hao Kai Zhang Aihua Zheng Hezhong Tian 2022Journal of Environmental Sciences2022,34,11:3
19基于OWL和Horn子句的β-PSML语言框架显示文摘提出了将OWL和Horn子句相结合构建β-PSML语言,它既可以表示OWL中不能表示的多元关系,又可以表示Horn子句难以表示的有丰富等级结构的领域模型。提出的β-PSML语言是一种语义Web中新的知识表示方法,利用该β-PSML语言的推理功能可以完成语义Web中的查询。苏依拉 郑磊 刘椿年 钟宁 LIU Jiming 2005计算机工程2005,31,23:3
20Mass concentrations and temporal profiles of PM10, PM2.5 and PM1 near major urban roads in Beijing显示文摘下午 10, 下午 2.5 和下午 1 的集体集中在六个时期期间在北京在主要道路附近被测量:2001 的夏天和冬季, 2007 的冬季,和时期在前,在期间并且在 2008 个北京奥运会以后。自从为机动车辆的努力帮助了从车辆的快速的生长抵消排出物的增加的控制,在路边的平均下午 2.5 集中在一个相对小的范围上在在 2001 和 2008 之间的采样时期期间波动。与控制在奥林匹克期间测量的暂时的交通的实现,清楚的 V 塑造了弯曲证明在路边的微粒物质和另外的气体的空气污染物质的集中随着时间的过去被识别。分别地,下午 10, 下午 2.5, 公司并且不的平均集中从 6 月在 31.2% , 46.3% , 32.3% 和 35.4% 减少了到 8 月;这被所有空气污染物质的反弹在 2008 年 12 月跟随。主要道路附近的每日的下午 10 集中在非奥林匹克时期为 61.2% of the days 超过了国家周围的空气质量标准(等级 II ) ,当时仅仅为 12.5% 在奥林匹克期间。主要道路附近的下午 2.5/ 下午 10 的吝啬的比率在 0.55 点仍然保持相对稳定(Liu YANG Ye WU Jiaqi LI Shaojie SONG Xuan ZHENG Jiming HAO 2015Frontiers of Environmental Science & Engineering2015,9,4:3
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