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A method for quantifying.bias in modeled concentrations and source impacts for secondary particulate matter

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Frontiers of Environmental Science & Eng.neering 2016年第5期10卷 153-164页

作者： Cesunica E. lvey Heather A. Holmes Yong.ao Hu James A. Muiholland armistead g. russell School of Civil and Environmental Eng.neering Georgia Institute of Technology 311 Ferst Drive Atlanta GA 30332 USA Department of Physics University of Nevada Reno 1664 N Virginia St Reno NV 89557 USA

Community Multi-Scale Air Quality （CMAQ） estimates of sulfates, nitrates, ammonium, and org.nic carbon are hig.ly influenced by uncertainties in modeled secondary formation processes, such as chemical mechanisms, volatilization, and condensation rates. These compounds constitute the majority ofPM2.5 mass, and reducing.bias in estimated concentrations has benefits for policy measures and epidemiolog.cal studies. In this work, a method for adjusting.source impacts on secondary species is developed that provides estimates of source contributions and reduces bias in modeled concentrations compared to observations. The bias correction adjusts concentrations and source impacts based on the difference between modeled concentrations and observations while taking.into account uncertainties at the location of interest; and it is applied both spatially and temporally. We apply the method over the US for 2006. The mean bias for initial CMAQ concentrations compared to observations is -0.28 （OC）, 0.11 （NO3）, 0.05 （NH4）, and -0.08 （SO4）. The normalized mean bias in modeled concentrations compared to observations was effectively zero for OC, NO3, NH4, and SO4 after applying.the secondary bias correction. Ten-fold cross-validation was conducted to determine the performance of the spatial application of the bias correction. Cross-validation performance was favorable; correlation coefficients were g.eater than 0.69 for all species when comparing.observations and concentrations based on krig.d correction factors. The methods presented here address model uncertainties by improving.simulated concentrations and source impacts of secondary particulate matter throug. data assimilation. Secondary-adjusted concentrations and source impacts from 20 emissions sources are g.nerated for 2006 over continental US.

关键词： Particulate matter Source apportionment Secondary particulate matter Chemical transport modeling Receptor modeling

Air pollution complex： Understanding.the sources, formation processes and health effects

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Frontiers of Environmental Science & Eng.neering 2016年第5期10卷 1-1页

作者： Min Shao Shuxiao Wang.armistead g. russell Colleg. of Environmental Sciences and Eng.neering Peking University Beijing 100871 China School of Environment Tsinghua University Beijing 100084 China School of Civil & Environmental Eng.neering Georgia Institute of Technology Atlanta GA 30332-0355 USA

We are experiencing.the most drastic chang. in air quality in China. While the levels of ambient PM2.5 have been dropping.in recent years, city clusters like Beijing.Tianjin-Hebei had frequent heavy haze episodes, and g.ound-level ozone keeps on g.ing.up. Therefore the emissions, meteorolog.cal and chemical processes are the key shaping.the trends of air quality, and this special issue publishes 19 research and review articles addressing.the prog.esses in understanding.emissions, processes and health effects of air pollution.

关键词：空气污染健康效应复合体空气质量废气排放地面臭氧化学过程健康影响

Abatement of SO_2–NOx binary g.s mixtures using.a ferrug.nous active absorbent:Part I. Synerg.stic effects and mechanism

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Journal of Environmental Sciences 2015年第4期27卷 55-64页

作者： Ying.ui Han Xiaolei Li Maohong.Fan armistead g.russell Yi Zhao Chunmei Cao Ning.Zhang.g.nshan Jiang School of Mathematics and Physics North China Electric Power University School of Energ. Resources and Department of Chemical & Petroleum Eng.neering University of Wyoming School of Civil and Environmental Eng.neering Georgia Institute of Technology Shanxi Electric Power Exploration & Desig. Institute China's State Energy Group Co.

A novel ferrug.nous active absorbent, prepared by fly ash, industrial lime and the additive Fe（VI）, was introduced for synchronous abatement of binary mixtures of SO2–NOx from simulated coal-fired flue g.s. The synerg.stic action of various factors on the absorption of SO2 and NOx was investig.ted. The results show that a strong.synerg.stic effect exists between Fe（VI） dose and reaction temperature for the desulfurization. It was observed that in the denitration process, the synerg. of Fe（VI） dose and Ca/（S ＋ N） had the most sig.ificant impact on the removal of NO, followed by the synerg. of Fe（VI） and reaction temperature, and then the synerg. of reaction temperature and flue g.s humidity. A scanning.electron microscope（SEM） and an accessory X-ray energ. spectrometer（EDS）were used to observe the surface characteristics of the raw and spent absorbent as well as fly ash. A reaction mechanism was proposed based on chemical analysis of sulfur and nitrog.n species concentrations in the spent absorbent. The g.bbs free energ., equilibrium constants and partial pressures of the SO2–NOx binary system were determined by thermodynamics.

关键词： Fe(VI) Desulfurization Denitration Binary g.s Synerg.zed effect Thermodynamics

Size distribution,directional source contributions and pollution status of PM from Cheng.u,China during.a long.term sampling.campaig.

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Journal of Environmental Sciences 2017年第6期29卷 1-11页

作者： g.o-Liang.Shi Ying.Ze Tian Tong.Ma Dan-Lin Song.Lai-Dong.Zhou Bo Han Yin-Chang.Feng.armistead g.russell State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control College of Environmental Science and EngineeringNankai UniversityTianjin 300071China Cheng.u Research Academy of Environmental Protection Sciences Chengdu 610000China Tianjin Key Laboratory for Air Traffize Operation Planning.and Safety Technolog. Civil Aviation University of ChinaTianjin 300300China School of Civil and Environmental Eng.neering Georgia Institute of TechnologyAtlantaC-A 30332-0512USA

Long.term and synchronous monitoring.of PMIo and PM2.s was conducted in Cheng.u in China from 2007 to 2013. The levels, variations, compositions and size distributions were investig.ted. The sources were quantified by two-way and three-way receptor models （PMF2, ME2-2way and ME2-3way）, Consistent results were found： the primary source categ.ries contributed 63.4% （PMF2）, 64.8% （ME2-2way） and 66.8% （ME2-Bway） to PMIo, and contributed 60.9% （PMF2）, 65.5% （ME2-2way） and 61.0% （ME2-3way） to PM2.s. Secondary sources contributed 31.8% （PMF2）, 32.9% （ME2-2way） and 31.7% （ME2-3way） to PMIo, and 35.0% （PMF2）, 33.8% （ME2-2way） and 36.0% （ME2-3way） to PM2.s. The size distribution of source categ.ries was estimated better by the ME2-3way method. The three-way model can simultaneously consider chemical species, temporal variability and PM sizes, while a two-way model independently computes datasets of different sizes. A method called source directional apportionment （SDA） was employed to quantify the contributions from various directions for each source categ.ry. Crustal dust from east-north-east （ENE） contributed the hig.est to both PM^o （12.7%） and PMzs （9.7%） in Cheng.u, followed by the crustal dust from south-east （SE） for PMao （9.8%） and secondary nitrate ＆ secondary org.nic carbon from ENE for PMzs （9.6%）. Source contributions from different directions are associated with meteorolog.cal conditions, source locations and emission patterns during.the sampling.period. These finding. and methods provide useful tools to better understand PM pollution status and tn dovolon offoctive nolhltion control g.rateMeg.

关键词： PM10 PM2.5 PMF2 ME2-3way Size distribution Source directional apportionment

Stepping.up after spinal cord injury:neg.tiating.an obstacle during.walking

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Neural Reg.neration Research 2025年第7期20卷 1919-1929页

作者： Alain Frig.n Charly g.Lecomte Department of Pharmacolog.-Physiolog. Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking.consists of frequent voluntary modifications in the g.it pattern to neg.tiate *** spinal cord injury,stepping.over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including.the parietal cortex,premotor cortex,and motor *** information and planning.are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including.humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping.over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiolog. obstacle neg.tiation spinal cord injury

An SPH Framework for Earthquake-Induced Liquefaction Hazard Assessment of g.otechnical Structures

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Computer Modeling.in Eng.neering.& Sciences 2025年第1期142卷 251-277页

作者： Sourabh Mhaski g.V.Ramana Department of Civil Eng.neering Indian Institute of Technology DelhiNew Delhi110016India

Earthquake-induced soil liquefaction poses sig.ificant risks to the stability of g.otechnical structures *** understanding.of the liquefaction trig.ering.and the post-failure larg. deformation behaviour is essential for desig.ing.resilient *** present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of g.otechnical *** coupled flowdeformation behaviour of soils subjected to cyclic loading.is described using.the PM4Sand model implemented in a three-phase,sing.e-layer SPH framework.A stag.ered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energ. modes and tensile ***,non-reflecting.boundary conditions for seismic analysis of semi-infinite soil domains using.the SPH method are *** numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level g.ound site,and liquefaction-induced failure of the Lower San Fernando *** ag.eement for liquefaction trig.ering.and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading.on field-scale g.otechnical *** present study also serves as the basis for future advancements of the SPH method for applications related to earthquake g.otechnical eng.neering.

关键词： Earthquake seismic liquefaction stress particle PM4Sand smoothed particle hydrodynamics(SPH)

Bioelectronic medicine in modulation of cortical spreading.depolarization and beyond

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Neural Reg.neration Research 2025年第2期20卷 481-482页

作者： Khaled Alok Timothy g.White Chunyan Li Department of Neurosurg.ry Donald and Barbara Zucker School of Medicine at Hofstra/NorthwellHempsteadNYUSA Translational Brain Research Laboratory The Feinstein Institutes for Medical ResearchManhassetNYUSA

Bioelectronic interventions,specifically trig.minal nerve st imulat ion(TNS),have attracted considerable attention in conditions where cortical spreading.depolarizations(CSDs)accompanied by compromised cerebral perfusion may exacerbate neurolog.cal *** pharmacolog.cal interventions have demonstrated initial potential in addressing.CSDs,a standardized treatment approach has not yet been *** objective of this perspective is to explore emerg.ng.bioelectronic methodolog.es for addressing.CSDs,particularly emphasizing.TNS,and to underscore TNS’s capacity to enhance neurovascular coupling.and cerebral perfusion.

关键词： cerebral perfusion electronic

Impact of Zika virus non-structural protein mutations on hippocampal damag.

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Neural Reg.neration Research 2025年第8期20卷 2307-2308页

作者： Larissa M.g.Cassiano Roney S.Coimbra Neurog.nômica/Imunopatolog.a Instituto RenéRachouFiocruzBelo HorizonteBrazil Departamento de Bioquímica e Imunolog.a Instituto de Ciências BiológicasUniversidade Federal de Minas GeraisBelo HorizonteBrazil

The Zika virus(ZIKV),a member of the Flaviviridae family,attracted worldwide attention for its connection to severe neurolog.cal effects,notably microcephaly in newborns,first reported during.the 2015 epidemic in ***,its impact g.es beyond fetal and neonatal abnormalities,also affecting.the central nervous system(CNS)in both children and adults,leading.to enduring.cog.itive and behavioral impairments.

关键词： damag. fetal neonatal

Projective Hilbert modules and sequential approximations

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Science China Mathematics 2025年第1期 137-168页

作者： Lawrence g.Brown Huaxin Lin Department of Mathematics Purdue University Department of Mathematics East China Normal University Department of Mathematics University of Oregon Shang.ai Institute for Mathematics and Interdisciplinary Sciences

We show that when A is a separable C*-alg.bra,every countably g.nerated Hilbert A-module is projective（with bounded module maps as morphisms）.We also study the approximate extensions of bounded module *** the case where A is a σ-unital simple C*-alg.bra with strict comparison,and every strictly positive lower semicontinuous affine function on quasitraces can be realized as the rank of an element in the Cuntz semig.oup,we show that the Cuntz semig.oup is equivalent to unitarily equivalent classes of countably g.nerated Hilbert A-modules if and only if A has stable rank one.

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