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Spatiotemporal heterogeneity of magnetic enhancement mechanisms in aeolian deposits on the southern Tibetan Plateau:Implications for paleoclimatic reconstruction in mountainbasin systems
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作者 WANG Haoyu YANG Junhuai +9 位作者 QU Wenxi WANG Linkai ZHANG Canyi LIU Xin TANG Jinmeng GAO Fuyuan CHEN Zixuan WANG Shuyuan FAN Yijiao WU Duo 《Journal of Geographical Sciences》 2026年第1期177-198,共22页
Aeolian deposits across the Yarlung Zangbo River Basin on the southern Tibetan Plateau record the landscape and atmospheric evolution of Earth's Third Pole.The complex mountain-basin system exhibits nonlinear resp... Aeolian deposits across the Yarlung Zangbo River Basin on the southern Tibetan Plateau record the landscape and atmospheric evolution of Earth's Third Pole.The complex mountain-basin system exhibits nonlinear responses to climate forcing,complicating the interpretation of its high-altitude environmental dynamics.Investigating the magnetic enhancement mechanism of aeolian deposits offers an opportunity to decipher climate signals.Our analysis of three aeolian sections from the basin indicates that magnetic minerals are predominantly low-coercivity ferrimagnetic minerals,and grain sizes fine from upper to lower reaches due to climate shifts from arid to humid.Magnetic enhancement in the upper reaches primarily originates from dust input,while dust input and pedogenesis contribute variably over time in the middle and lower reaches.Similar complex patterns occur in the Ili basin,a mountain-basin system in northwestern China.They differ from the Chinese Loess Plateau,where long-distance-transported dust is well-mixed and the pedogenic enhancement model is applied,and desert peripheries where short-distance dust is transported and the dust input model is applied.We summarize the magnetic enhancement mechanisms in various settings and offer a new framework for applying magnetic techniques in paleoclimate reconstruction within global mountain-basin systems,which highlights the need for caution in interpreting their magnetic susceptibility records. 展开更多
关键词 HOLOCENE aeolian deposits magnetic properties climate change Yarlung Zangbo River Basin
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Damage effectiveness characterization model of laser weapon systems under the impact of spatial position and atmospheric condition
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作者 LIU Wei ZHANG Lin +3 位作者 YUN Tao MENG Xianliang ZHANG Bo SONG Yafei 《Journal of Systems Engineering and Electronics》 2025年第5期1281-1295,共15页
The emergence of laser technology has led to the gradual integration of laser weapon system(LaWS)into military scene,particularly in the field of anti-unmanned aerial vehicle(UAV),showcasing significant potential.Howe... The emergence of laser technology has led to the gradual integration of laser weapon system(LaWS)into military scene,particularly in the field of anti-unmanned aerial vehicle(UAV),showcasing significant potential.However,A current limitation lies in the absence of a comprehensive quantitative approach to assess the capabilities of LaWS.To address this issue,a damage effectiveness characterization model for LaWS is established,taking into account the properties of laser transmission through the atmosphere and the thermal damage effects.By employing this model,key parameters pertaining to the effectiveness of laser damage are determined.The impact of various spatial positions and atmospheric conditions on the damage effectiveness of LaWS have been examined,employing simulation experiments with diverse parameters.The conclusions indicate that the damage effectiveness of LaWS is contingent upon the spatial position of the target,resulting in a diminished effectiveness to damage on distant,low-altitude targets.Additionally,the damage effectiveness of LaWS is heavily reliant on the atmospheric condition,particularly in complex settings such as midday and low visibility conditions,where the damage effectiveness is substantially reduced.This paper provides an accurate and effective calculation method for the rapid decisionmaking of the operators. 展开更多
关键词 laser weapon system damage effectiveness atmospheric transmission thermal damage anti-unmanned aerial vehicle
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Spectroscopic Study of the Late B-type Eclipsing Binary System AR Aurigae A and B:Towards Clarifying the Differences in Atmospheric Parameters and Chemical Abundances
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作者 Yoichi Takeda 《Research in Astronomy and Astrophysics》 2025年第2期160-172,共13页
AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the dise... AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the disentangled spectra,in order to determine their atmospheric parameters and elemental abundances.The effective temperature and microturbulence(determined from the equivalent widths of Fe II lines)turned out to be(11,150 K,0.9 km s^(-1))and(10,650 K,0.1 km s^(-1))for A and B,respectively.The chemical abundances of 28 elements were then derived while taking into account the non-LTE effect for Z≤15 elements(Z:atomic number).The following trends were elucidated for[X/H](abundance of X relative to the Sun):(1)Qualitatively,[X/H]shows a rough global tendency to increase with Z,with the gradient steeper for A than for B.(2)However,considerable dispersion is involved for A,since prominently large peculiarities are seen in specific elements reflecting the characteristics of HgMn stars(e.g.,very deficient N,Al,Sc,Ni;markedly overabundant P,Mn).(3)In contrast,the Z-dependence of[X/H]for B tends to be nearly linear with only a small dispersion.These observational facts may serve as a key to understanding the critical condition for the emergence of the chemical anomaly. 展开更多
关键词 stars:abundances stars:atmospheres (stars:)binaries:spectroscopic stars:chemically peculiar stars:early-type stars:individual(AR Aur)
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Vertical Structure and Energy Transfer of Stationary Planetary Waves in Different Prescribed Atmospheric Stratifications
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作者 Wenqi ZHANG Lin WANG 《Advances in Atmospheric Sciences》 2026年第1期233-246,共14页
This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlyin... This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations. 展开更多
关键词 planetary waves vertical propagation atmospheric stratification stratospheric circulation group velocity
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Predictable and Unpredictable Modes of Northern Hemisphere Atmospheric Circulation in CMIP6:Evaluation and Projections
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作者 Kairan YING Dabang JIANG Linhao ZHONG 《Advances in Atmospheric Sciences》 2026年第1期135-156,共22页
Climate models are essential for understanding past,present,and future changes in atmospheric circulation,with circulation modes providing key sources of seasonal predictability and prediction uncertainties for both g... Climate models are essential for understanding past,present,and future changes in atmospheric circulation,with circulation modes providing key sources of seasonal predictability and prediction uncertainties for both global and regional climates.This study assesses the performance of models participating in phase 6 of the Coupled Model Intercomparison Project in simulating interannual variability modes of Northern Hemisphere 500-hPa geopotential height during winter and summer,distinguishing predictable(potentially predictable on seasonal or longer timescales)and unpredictable(intraseasonal and essentially unpredictable at long range)components,using reanalysis data and a variance decomposition method.Although most models effectively capture unpredictable modes in reanalysis,their ability to reproduce dominant predictable modes-specifically the Pacific-North American pattern,Arctic Oscillation,and Western Pacific Oscillation in winter,and the East Atlantic and North Atlantic Oscillations in summer-varies notably.An optimal ensemble is identified to distinguish(a)predictable-external modes,dominated by external forcing,and(b)predictable-internal modes,associated with slow internal variability,during the historical period(1950-2014)and the SSP5-8.5 scenario(2036-2100).Under increased radiative forcing,the leading winter/summer predictable-external mode exhibits a more uniform spatial distribution,remarkably larger trend and annual variance,and enhanced height-sea surface temperature(SST)covariance under SSP5-8.5 compared to historical conditions.The dominant winter/summer predictable-internal modes also exhibit increased variance and height-SST covariance under SSP5-8.5,along with localized changes in spatial configuration.Minimal changes are observed in spatial distribution or variance for dominant winter/summer unpredictable modes under SSP5-8.5.This study,from a predictive perspective,deepens our understanding of model uncertainties and projected changes in circulations. 展开更多
关键词 interannual mode of atmospheric circulation CMIP6 predictable unpredictable EVALUATION PROJECTION
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Latent and sensible heat fluxes in a very unstable atmospheric surface layer and weak-wind conditions in a tropical coastal ocean
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作者 Haitem M Almdhun Yusri Yusup +3 位作者 Ehsan Jolous Jamshidi Abdulghani Swesi Muhammad Fikri Sigid Abigail Adomako 《Atmospheric and Oceanic Science Letters》 2026年第1期47-52,共6页
The atmospheric surface layer of the tropical coastal ocean is commonly very unstable and experiences weakwind conditions.How the latent(LE)and sensible(H)heat fluxes behave under such conditions are unclear because o... The atmospheric surface layer of the tropical coastal ocean is commonly very unstable and experiences weakwind conditions.How the latent(LE)and sensible(H)heat fluxes behave under such conditions are unclear because of the lack of observation stations in the tropics.Thus,this study aims to analyze LE and H and the microclimate parameters influencing them.The authors deployed an eddy covariance system in a tropical coastal region for seven months.The microclimate parameters investigated were wind speed(U),vapor pressure deficit(Δe),temperature difference(ΔT),wind-vapor pressure deficit(UΔe),wind-temperature difference(UΔT),and atmospheric stability(z/L),where z is height and L is the Monin–Obukhov length.On the daily time scale,the results show that LE was more associated with U thanΔe,while H was more related toΔT than U.Cross-wavelet analysis revealed the strong coherence in the LE-U relationship for periods between one and two days,and for H–ΔT,0.5 to 1 day.Correlation and regression analyses confirmed the time series analyses results,where strong positive correlation coefficients(r)were obtained between LE and U(r=0.494)and H andΔT(r=0.365).Compared to other water bodies,the transfer coefficient of moisture(CE N)was found to be small(=0.40×10^(-3))and independent of stability;conversely,the transfer coefficient of heat(CH N)was closer to literature values(=1.00×10^(-3))and a function of stability. 展开更多
关键词 Latent heat Sensible heat atmospheric surface layer Tropical coastal sea
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Mechanisms of ENSO's cross-seasonal modulation of winter–spring atmospheric river activity over East Asia
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作者 Yuliang Zhou Wentao Jia +1 位作者 Weimin Zhang Huizan Wang 《Atmospheric and Oceanic Science Letters》 2026年第1期66-71,共6页
In this study,based on MERRA-2 reanalysis data and a multi-algorithm integrated atmospheric river(AR)iden-tification method,the authors reveal the cross-seasonal regulation mechanism of El Niño-Southern Oscillati... In this study,based on MERRA-2 reanalysis data and a multi-algorithm integrated atmospheric river(AR)iden-tification method,the authors reveal the cross-seasonal regulation mechanism of El Niño-Southern Oscillation(ENSO)on winter-spring AR activities in East Asia.The results show that ENSO asymmetrically modulates AR ac-tivity through teleconnection and hysteresis effects,and has significant enhancement/inhibition effects on ARs in different regions.At the onset of El Niño,enhanced southwesterly flow at the western edge of the western Pacific subtropical high(WPSH)leads to enhanced AR activity in the western Pacific,and anomalous southerly winds in the Indian Ocean promote northward transport of water vapor in the Arabian Sea and Bay of Bengal.With a three-month lag,the weakening and eastward retreat of the WPSH weakens the low-latitude AR activity,but persistent southerly winds in the Bay of Bengal maintain the AR activity over Southwest China.The mid-to high-latitude AR response exhibits delayed dynamics,initially dominated by the synergistic effect of the southward deviation of the upper-air rapids and the low-level convergence(double-rapid-flow effect)and later modulated by the Pacific-North American teleconnection(PNA)-triggered East Asian ridge,which enhances the precipitation efficiency through prolonged frontal activity and enhanced cold-warm airmass convergence.Overall,El Niño promotes the development of low-and midlatitude AR activity in East Asia,while La Niña promotes(maritime continental)AR activity in the tropics.This study establishes the“ENSO teleconnection→circulation adjust-ment→East Asian AR response”chain,revealing a cross-seasonal lagged response mechanisms of East Asian AR activity,and provides a theoretical basis for winter and spring climate prediction and extreme precipitation forecasting. 展开更多
关键词 ENSO atmospheric river Western Pacific subtropical high East Asia Lagged response
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Comparison of atmospheric gravity wave event statistics between Dandong and Lhasa
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作者 YiXuan Chen Chang Lai +2 位作者 QinZeng Li JiYao Xu Wei Yuan 《Earth and Planetary Physics》 2026年第1期176-185,共10页
Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dand... Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dandong station have wavelengths ranging from 30 to 60 km,periods from 14 to 20 min,horizontal speeds from 30 to 60 m/s,and relative intensities from 0.4%to 0.6%,respectively.The parameters of 202 events recorded at the Lhasa station mainly vary within 15-35 km in horizontal wavelength,4-6 min in period,40-100 m/s in horizontal velocity,and 0.1%-0.3%in relative intensity.The occurrence rate peaks in winter and summer at Dandong and the peak in summer are absent at Lhasa because of the lack of convective weather.The seasonal propagation directions of the waves are influenced by both the wind field-filtering effect and the distribution of wave sources.In spring,because of the southeastward background wind field,fewer southeastward events are observed at the Dandong station.The situation at the Lhasa station is similar.In summer,both the Lhasa and Dandong stations are dominated by northeastward AGWs,which can be attributed to the southwestward wind.In autumn,ray-tracing results show that the events at Dandong mainly originate from wind shear,whereas the events at the Lhasa station are triggered by convective weather.The location of the wave sources determines the trend of the propagation directions at the Dandong and Lhasa stations in autumn.In winter,because of the eastward wind,more events are propagating to the southwest at the Dandong station. 展开更多
关键词 atmospheric gravity waves backward ray-tracing method wind field filtering convective precipitation
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Multiscale“pore-film”cross-linked photothermal hygroscopic sponge for solar-driven atmospheric water harvesting
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作者 Yan Li Minmin Li +1 位作者 Fan Dong Wen Cui 《Chinese Chemical Letters》 2026年第2期649-654,共6页
Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,cou... Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,could become a sustainable alternative.Sorption-based atmospheric water harvesting(SAWH)has emerged as an available solution,yet conventional desorption methods relying on energy-intensive electrical heating hinder its scalability.Herein,a photothermal hygroscopic sponge has been developed for solar-driven atmospheric water harvesting.The composites combine a malleable melamine sponge skeleton,lithium chloride as a hygroscopic agent,and hydrangea-like molybdenum disulfide as a photothermal component,forming a multiscale“pore-film”cross-linked structure by an eco-friendly immersion-freeze-drying method.The optimized sample achieves exceptional hygroscopic capacity(3.92 g/g at 90%RH)and freshwater production efficiency(87.77%),which is attributed to synergistic effects of porous skeleton based crosslinked structures and“pore-film”structures,and outstanding photothermal conversion efficiency of MoS2.The unique structure could stabilize LiCl to prevent leakage,increase mass transfer effectiveness of whole SWAH process,and enable flexibility for diverse applications.We carried out outdoor experiments to demonstrate a solar-driven water production rate of 4.22 L m-2 d-1 without external energy input.This work provides insights into sustainable freshwater generation and promotes green energy utilization in addressing global water scarcity. 展开更多
关键词 Sorption-based atmospheric water HARVESTING Pore-film structure Hygroscopic sponge Photothermal conversion Mass and heat transfer
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Grassland ecosystems of Tajikistan:Plant species diversity,ecological restoration,and sustainable management
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作者 Hikmat HISORIEV LI Yaoming +3 位作者 HUANG Wenjun FAN Lianlian Mekhrovar OKHONNIYOZOV MA Xuexi 《Regional Sustainability》 2026年第1期23-36,共14页
Livestock farming is a critical pillar of Tajikistan’s national economy and livelihood security.However,significant economic challenges in the country have led to the degradation of grassland ecosystems.This degradat... Livestock farming is a critical pillar of Tajikistan’s national economy and livelihood security.However,significant economic challenges in the country have led to the degradation of grassland ecosystems.This degradation has not only reduced the productivity of grassland ecosystems but also severely impacted their ecological functions.A particularly concerning consequence is the threat to biodiversity,as the survival and persistence of endemic,rare,and endangered plant species are at serious risk,thereby diminishing the value of species’genetic resources.Based on the data from multiple sources such as literature reviews,field observations,and national statistics,this study employed a systematic literature review and meta-analysis to investigate the current status,causes of degradation,and restoration measures for grassland ecosystems in Tajikistan.The results revealed that Tajikistan’s grassland ecosystems support exceptionally high plant species diversity,comprising over 4500 vascular plant species,including nearly 1500 endemic and sub-endemic taxa that constitute a unique genetic reservoir.These ecosystems are experiencing severe degradation,characterized by significantly reduced vegetation cover and declining species richness.Palatable forage species are increasingly being displaced by unpalatable,thorny,and poisonous species.The primary drivers of degradation include excessive grazing pressure,which disrupts plant reproductive cycles and regeneration capacity,habitat fragmentation due to urbanization and infrastructure development,and uncontrolled exploitation of medicinal and edible plants.Climate change,particularly rising temperatures and altered precipitation patterns,further exacerbates these anthropogenic pressures.Ecological restoration experiments suggested that both ecosystem productivity and plant species diversity are significantly enhanced by systematic reseeding trials using altitude-adapted native species.These findings underscore the necessity of establishing scientifically grounded approaches for ecological restoration. 展开更多
关键词 Grassland ecosystem degradation Plant communities OVERGRAZING Ecological restoration Climate change TAJIKISTAN
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Thermal Performance and Design Optimization of a High-Concentration Photovoltaic System for Arid Environments
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作者 Taher Maatallah Nagmeldeen A.M.Hassanain +6 位作者 GaydaaAl Zohbi Farooq Saeed Muhammad Saleem Nassir Hariri Mohamed Elsharawy Tapas Kumar Mallick Fahad Gallab Al-Amri 《Frontiers in Heat and Mass Transfer》 2026年第1期140-169,共30页
High-concentration photovoltaic(HCPV)systems present significant thermal management challenges due to the intense heat fluxes generated under concentrated solar irradiation,especially in arid environments.Effective he... High-concentration photovoltaic(HCPV)systems present significant thermal management challenges due to the intense heat fluxes generated under concentrated solar irradiation,especially in arid environments.Effective heat dissipation is critical to prevent performance degradation and structural failure.This study investigates the thermal performance and design optimization of an enhanced HCPV module,integrating numerical,analytical,and experimental methods.A coupled optical-thermal-electrical model was developed to simulate ray tracing,heat transfer,and temperature-dependent electrical behaviour,with predictions validated under real-world desert conditions.Compared to a baseline commercial module operating at 106℃,the optimized design achieved a peak temperature reduction of 16℃,lowering the cell temperature to 90℃under a concentration ratio of 961×and direct normal irradiance(DNI)of 950 W/m^(2).The total thermal resistance was reduced from 0.25 to 0.15 K/W(a 40%improvement),and the electrical efficiency increased from 37.5%to 38.6%,representing a relative gain of approximately 3.1%.The system consistently maintained a fill factor exceeding 78%,underscoring stable performance under high thermal load.These findings demonstrate that targeted thermal design,informed by integrated modeling,is essential for unlocking the reliability and efficiency of high-flux solar energy systems. 展开更多
关键词 Arid climate applications convective cooling heat transfer enhancement high-concentration photovoltaics(HCPV) heat sink optimization numerical thermal analysis thermal management thermal resistance
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Spatiotemporal evolution of net ecosystem productivity and the driving mechanisms in Horqin Sandy Land,China
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作者 XU Xiaona ZHANG Huayong 《Journal of Arid Land》 2026年第1期34-55,共22页
Vegetation in terrestrial ecosystems as a carbon sink is a crucial factor in mitigating global warming and reaching carbon neutrality targets,although the drivers of net ecosystem productivity(NEP)under combined human... Vegetation in terrestrial ecosystems as a carbon sink is a crucial factor in mitigating global warming and reaching carbon neutrality targets,although the drivers of net ecosystem productivity(NEP)under combined human and environmental pressures remain poorly understood.In this study,we analyzed the spatiotemporal evolution of NEP in the Horqin Sandy Land,China from 2000 to 2020,and observed the variation in NEP across different land use types.We further identified and quantified the effects of human activities,topographical features,climatic conditions,and soil properties on NEP through the application of structural equation modeling(SEM)and boosted regression trees(BRT).The results showed that the multi-year average NEP ranged from–137.79 to 461.96 g C/m^(2) in the Horqin Sandy Land,with 88.21%of the area showing a significant increasing trend.Among different land use types,forestland exhibited the highest NEP values,followed by cropland,grassland,impervious land,and unused land.The NEP in carbon sink areas was primarily regulated by potential evapotranspiration(negatively correlated)and precipitation(positively correlated).Slope was identified as the most significant positive determinant in carbon source areas.Forestland exhibited climate–topography interactions driving NEP,whereas cropland and grassland relied on temperature;unused land and impervious land were susceptible to land use/cover change and human footprint.This study has significant implications for maintaining the carbon sink function and promoting ecological engineering programs that aim to enhance the capacity of terrestrial carbon sinks in the semi-arid agro-pastoral ecotone. 展开更多
关键词 net ecosystem productivity(NEP) land use/cover change(LUCC) carbon sink climate change human activities structural equation modeling(SEM) semi-arid agro-pastoral ecotone
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SST INTRASEASONAL OSCILLATION AND ATMOSPHERIC FORCING SYSTEM OF THE SOUTH CHINA SEA 被引量:2
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作者 高荣珍 周发秀 方文东 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2000年第4期289-296,共8页
This study used National Center for Environmental Prediction (NCEP) reanalysis data to confirm that the variance of sea surface temperature (SST) in the South China Sea (SCS) has pronounced intraseasonal oscillations ... This study used National Center for Environmental Prediction (NCEP) reanalysis data to confirm that the variance of sea surface temperature (SST) in the South China Sea (SCS) has pronounced intraseasonal oscillations characterized by quasi standing waves; and was aimed to document how intraseasonal time scale SST formed and developed in the SCS. The results derived from the composite analysis indicated the existence of a local low level atmospheric dynamic forcing system over the SCS. The main formation mechanism of SST intraseasonal oscillation is the low level rotational atmospheric circulation forcing over the SCS on intraseasonal time scales and the solar radiation variations caused by cloud amount changes. 展开更多
关键词 SCS SST INTRASEASONAL OSCILLATION low level atmospheric FORCING
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Impact of atmospheric turbulence on coherent beam combining for laser weapon systems 被引量:9
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作者 Jan K.Jabczyński Przemysław Gontar 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第4期1160-1167,共8页
The performance of a laser weapon system based on coherent beam combining(CBC)depends on its propagation properties in the atmosphere.In this study,an analytical model based on partial coherent beam combining(PCBC)for... The performance of a laser weapon system based on coherent beam combining(CBC)depends on its propagation properties in the atmosphere.In this study,an analytical model based on partial coherent beam combining(PCBC)for assumed coherence coefficients between beams in a CBC lattice was developed.The Kolmogorov model of atmospheric turbulence and the Hufnagel-Valley model of C^(2)_(n) dependence on atmospheric parameters were implemented.Novel simplified metrics were proposed to assess the CBC performance.Several beam profiles(super-Gaussian,truncated Gaussian,etc.)and geometries were analyzed in terms of maximal intensity in the far field.An approximate formula for PCBC efficiency dependent on the Fried radius was proposed.The results of CBC modeling were compared to those of the Gaussian beam propagation model in a turbulent atmosphere.The dependence of CBC performance on the C^(2)_(n) parameter,range,and elevation angle was analyzed.It could be concluded that the application of CBC for medium and long range propagation is impractical without an effective adaptive optics system. 展开更多
关键词 Laser beams Beam combining COHERENCE Atmosphere turbulences
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Microwave assisted digestion followed by ICP-MS for determination of trace metals in atmospheric and lake ecosystem 被引量:12
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作者 Manan Ahmed Ying Hui Chin +1 位作者 Xinxin Guo Xing-Min Zhao 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第5期1-10,共10页
The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigat... The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season (before and after precipitation) between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid- liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc (133.50-419.30 μg/m3) and aluminum (53.58-378.93 μg/m3) had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters (pH and turbidity) and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere. 展开更多
关键词 Trace metals Microwave digestion ICP-MS atmospheric environment Lake ecosystem
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Stability for basic system of equations of atmospheric rhotion 被引量:2
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作者 施惟慧 徐明 王曰朋 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第2期261-268,共8页
The topological characteristics for the basic system of equations of atmospheric motion were analyzed with the help of method provided by stratification theory. It was proved that in the local rectangular coordinate s... The topological characteristics for the basic system of equations of atmospheric motion were analyzed with the help of method provided by stratification theory. It was proved that in the local rectangular coordinate system the basic system of equations of atmospheric motion is stable in infinitely differentiable function class. In the sense of local solution, the necessary and sufficient conditions by which the typical problem for determining solution is well posed were also given. Such problems as something about "speculating future from past" in atmospheric dynamics and how to amend the conditions for determining solution as well as the choice of underlying surface when involving the practical application were further discussed. It is also pointed out that under the usual conditions, three motion equations and continuity equation in the basic system of equations determine entirely the property of this system of equations. 展开更多
关键词 basic system of equations of atmospheric motion STABILITY stratificationtheory transversal stratum
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In situ monitoring of atmospheric nitrous acid based on multi-pumping flow system and liquid waveguide capillary cell 被引量:4
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作者 Yuhan Liu Keding Lu +6 位作者 Huabin Dong Xin Li Peng Cheng Qi Zou Yusheng Wu Xingang Liu Yuanhang Zhang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2016年第5期273-284,共12页
In the last four decades, various techniques including spectroscopic, wet chemical and mass spectrometric methods, have been developed and applied for the detection of ambient nitrous acid(HONO). We developed a HONO... In the last four decades, various techniques including spectroscopic, wet chemical and mass spectrometric methods, have been developed and applied for the detection of ambient nitrous acid(HONO). We developed a HONO detection system based on long path photometry which consists of three independent modules i.e., sampling module, fluid propulsion module and detection module. In the propulsion module, solenoid pumps are applied. With solenoid pumps the pulsed flow can be computer controlled both in terms of pump stroke volume and pulse frequency, which enables the attainment of a very stable flow rate. In the detection module, a customized Liquid Waveguide Capillary Cell(LWCC) is used. The customized LWCC pre-sets the optical fiber in-coupling with the liquid wave guide, providing the option of fast startup and easy maintenance of the absorption photometry. In summer 2014, our system was deployed in a comprehensive campaign at a rural site in the North China Plain. More than one month of high quality HONO data spanning from the limit of detection to 5 ppb were collected. Intercomparison of our system with another established system from Forschungszentrum Juelich is presented and discussed. In conclusion, our instrument achieved a detection limit of 10 ppt V within2 min and a measurement uncertainty of 7%, which is well suited for investigation of the HONO budget from urban to rural conditions in China. 展开更多
关键词 HONO Photometry Field campaign atmospheric chemistry
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Scrutinizing the atmospheric greenhouse effect and its climatic impact 被引量:2
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作者 Gerhard Kramm Ralph Dlugi 《Natural Science》 2011年第12期971-998,共28页
In this paper, we scrutinize two completely different explanations of the so-called atmospheric greenhouse effect: First, the explanation of the American Meteorological Society (AMS) and the World Meteorological Organ... In this paper, we scrutinize two completely different explanations of the so-called atmospheric greenhouse effect: First, the explanation of the American Meteorological Society (AMS) and the World Meteorological Organization (W?MO) quan- tifying this effect by two characteristic temperatures, secondly, the explanation of Ramanathan et al. [1] that is mainly based on an energy-flux budget for the Earth-atmosphere system. Both explanations are related to the global scale. In addition, we debate the meaning of climate, climate change, climate variability and climate variation to outline in which way the atmospheric greenhouse effect might be responsible for climate change and climate variability, respectively. In doing so, we distinguish between two different branches of climatology, namely 1) physical climatology in which the boundary conditions of the Earth-atmosphere system play the dominant role and 2) statistical climatology that is dealing with the statistical description of fortuitous weather events which had been happening in climate periods;each of them usually comprises 30 years. Based on our findings, we argue that 1) the so-called atmospheric greenhouse effect cannot be proved by the statistical description of fortuitous weather events that took place in a climate period, 2) the description by AMS and W?MO has to be discarded because of physical reasons, 3) energy-flux budgets for the Earth-atmosphere system do not provide tangible evidence that the atmospheric greenhouse effect does exist. Because of this lack of tangible evidence it is time to acknowledge that the atmospheric greenhouse effect and especially its climatic impact are based on meritless conjectures. 展开更多
关键词 Physical CLIMATOLOGY STATISTICAL CLIMATOLOGY atmospheric GREENHOUSE Effect Earth-Atmosphere system
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Systemic study on the safety of immuno-deficient nude mice treated by atmospheric plasma-activated water 被引量:2
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作者 许德晖 崔庆杰 +7 位作者 许宇静 王冰川 田苗 李乔松 刘志杰 刘定新 陈海兰 孔刚玉 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第4期17-23,共7页
Cold atmospheric-pressure plasma is a new technology, widely used in many fields of biomedicine,especially in cancer treatment. Cold plasma can selectively kill a variety of tumor cells, and its biological safety in c... Cold atmospheric-pressure plasma is a new technology, widely used in many fields of biomedicine,especially in cancer treatment. Cold plasma can selectively kill a variety of tumor cells, and its biological safety in clinical trials is also very important. In many cases, the patient’s immune level is relatively low, so we first studied the safety assessment of plasma treatment in an immunocompromised animal model. In this study, we examined the safety of immuno-deficient nude mice by oral lavage treatment of plasma-activated water, and studied the growth status, main organs and blood biochemical indexes. Acute toxicity test results showed that the maximum dose of plasma treatment for 15 min had no lethal effect and other acute toxicity. There were no significant changes in body weight and survival status of mice after 2 min and 4 min of plasma-activated water(PAW)treatment for 2 weeks. After treatment, the major organs, including heart, liver, spleen, lung and kidney, were not significantly changed in organ coefficient and tissue structure. Blood biochemical markers showed that blood neutrophils and mononuclear cells were slightly increased, and the others remained unchanged. Liver function, renal function, electrolytes, glucose metabolism and lipid metabolism were not affected by different doses of PAW treatment. The above results indicate that PAW treatment can be used to treat immuno-deficient nude mice without significant safety problems. 展开更多
关键词 cold atmospheric plasma plasma-activated water immuno-deficient nude mice safety study biochemical testing
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Optimization of harmonious development on regional energy-economy-atmospheric environment system 被引量:1
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作者 Ning Datong,Wang Lei(Chinese Real Estate Appraisal and Consulting Center,State Land Administration, Beiging,China.)(Institute of Environmental Sciences,Beijing Normal University,Beijing 100875,China) 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1996年第4期390-396,共7页
The energy,industrial economy and atmospheric environment were taken into account as a whole cornplex system in this study. Based on the application of grey system theory and the analysis of development coefficients a... The energy,industrial economy and atmospheric environment were taken into account as a whole cornplex system in this study. Based on the application of grey system theory and the analysis of development coefficients about major parameters of the system,the method of grey developrnent decision was approached, and a new concept-integrated development coefficient was put forward. Furthermore,the reasonable ranking of development decision within eight industrial sectors(building materials,coking,food and drink,chemical engineering,paper rnaking,machinery and electrical appliance,textile, mining)has been concluded from the viewpoint of economic growth, energy saving and ambient air quality protection. 展开更多
关键词 ECONOMY atmospheric environment grey development decision.
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