期刊文献+
共找到837篇文章
< 1 2 42 >
每页显示 20 50 100
Measuring stellar populations,dust attenuation and ionized gas at kpc scales in 10010 nearby galaxies using the integral field spectroscopy from MaNGA
1
作者 李牛 李成 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期1-7,共7页
As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectrosco... As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectroscopy(IFS)with a resolution of 1–2 kpc for104galaxies in the local universe during its six-year operation from July 2014 through August 2020.It is crucial to reliably measure the physical properties of the different components in each spectrum before one can use the data for any scientific study.In the past years we have made lots of efforts to develop a novel technique of full spectral fitting,which estimates a model-independent dust attenuation curve from each spectrum,thus allowing us to break the degeneracy between dust attenuation and stellar population properties when fitting the spectrum with stellar population synthesis models.We have applied our technique to the final data release of Ma NGA,and obtained measurements of stellar population properties and emission line parameters,as well as the kinematics and dust attenuation of both stellar and ionized gas components.In this paper we describe our technique and the content and format of our data products.The whole dataset is publicly available in Science Data Bank with the link https://doi.org/10.57760/sciencedb.j00113.00088. 展开更多
关键词 integral field spectroscopy stellar populations dust attenuation ionized gas
下载PDF
Toxicity and horizontal transfer of bifenthrin and dimefluthrin against the red imported fire ant, Solenopsis invicta Buren(Hymenoptera: Formicidae), and the efficacy of their dust applications in the field 被引量:1
2
作者 LIANG Ming-rong SHUANG You-ming +6 位作者 DENG Jie-fu PENG Li-ya ZHANG Sen-quan ZHANG Chen XU Yi-juan LU Yong-yue WANG Lei 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第5期1465-1476,共12页
The red imported fire ant,Solenopsis invicta Buren,poses a significant threat to biodiversity,agriculture,and public health in its introduced ranges.While chemicals such as toxic baits and dust are the main methods fo... The red imported fire ant,Solenopsis invicta Buren,poses a significant threat to biodiversity,agriculture,and public health in its introduced ranges.While chemicals such as toxic baits and dust are the main methods for S.invicta control,toxic baits are slow,requiring approximately one or two weeks,but dust can eliminate the colony of fire ants rapidly in just three to five days.To explore more active ingredients for fire ant control using dusts,the toxicity of bifenthrin and dimefluthrin,the horizontal transfer of bifenthrin and dimefluthrin dust and their efficacy in the field were tested.The results showed that the LD50(lethal dose) values of bifenthrin and dimefluthrin were 3.40 and 1.57 ng/ant,respectively.The KT50(median knockdown time) and KT95(95%knockdown time) values of a 20μg mL^(–1)bifenthrin dose were 7.179and 16.611 min,respectively.The KT50and KT95of a 5μg mL^(–1)dimefluthrin dose were 1.538 and 2.825 min,respectively.The horizontal transfers of bifenthrin and dimefluthrin among workers were effective.The mortality of recipients (secondary mortality) and secondary recipients (tertiary mortality) were both over 80%at 48 h after 0.25,0.50 and 1.00%bifenthrin dust treatments.The secondary mortality of recipients was over 99%at 48 h after 0.25,0.50 and 1.00% dimefluthrin dust treatments,but the tertiary mortality was below 20%.The field trial results showed that both bifenthrin and dimefluthrin exhibited excellent fire ant control effects,and the comprehensive control effects of 1.00%bifenthrin and dimefluthrin dusts at 14 d post-treatment were 95.87 and 85.70%,respectively. 展开更多
关键词 red IMPORTED fire ant PYRETHROIDS secondary transfer tertiary mortality contact toxic dust
下载PDF
Structural and Physicochemical Properties of Dust and Their Effect on Solar Modules Efficiency in Agadir-Morocco 被引量:1
3
作者 Abdellah Asbayou Ahmed Ihlal +2 位作者 Ismail Isknan Ahmed Soussi Lahoussine Bouhouch 《Journal of Renewable Materials》 SCIE EI 2023年第5期2249-2264,共16页
Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend... Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend on the nature and density of dust.The nature of dust was studied by means of scanning electron microscopy and energy dispersive x-ray spectroscopy.It was found that the granulometry of dust particles depends on the study area.For a dust density of around 20 g/m^(2),the maximum power Pmax of the solar panel decreases drastically from 30 to 20 W for the(HP)site,and no more than 14 W for the(AD)site.The diversity of the behavior of the soiled panel was explained in terms of the size of the particles collected from each area.The transmission of light across the front glass of the PV panel is more affected when the sizes of particles are small. 展开更多
关键词 agadir PV panel SOILING optical transmittance dust characterization
下载PDF
Occupational exposure to flour dust among bakery workers:prevalence,potential hazards and promising interventions
4
作者 Seyi-Samson Enitan Osareniro-Eguagie Osakue +4 位作者 Esther-Ngozi Adejumo Temitope-Oyewole Olusanya Emmanuel-Olusegun Ileoma Comfort-Bosede Enitan Nwachi-Idume Ogbonna 《Toxicology Advances》 2023年第4期33-44,共12页
Occupational exposure to flour dust within bakery environments presents significant health hazards to bakery personnel.Flour dust,generated as a byproduct during baking,becomes airborne during the baking process,thus ... Occupational exposure to flour dust within bakery environments presents significant health hazards to bakery personnel.Flour dust,generated as a byproduct during baking,becomes airborne during the baking process,thus constituting a respiratory threat.Adverse health consequences include respiratory diseases,skin irritation,allergic reactions,and potential long-term health impacts.Data indicates that a broad segment of bakery workers encounters exposure to flour dust,with specific subgroups,such as bakers and dough mixers,being particularly susceptible.Contributing factors to this exposure encompass insufficient ventilation and a lack of awareness.It is vital to assess exposure levels through air quality monitoring and health surveillance.Efficient interventions encompass engineering solutions(e.g.,ventilation systems,dust extraction),administrative measures(including training and the use of personal protective equipment),and the implementation of occupational health and safety programs.Collaborative efforts with healthcare professionals and regulatory authorities are paramount for achieving success.Case studies underscore the effectiveness of such interventions,resulting in improved worker health,thus underscoring the advantages of protective measures.Challenges in this endeavor include industry resistance to change,financial considerations,and issues related to compliance.Future recommendations entail further research,policy enhancements,and the involvement of industry stakeholders and labor unions in advocating for worker safety. 展开更多
关键词 flour dust bakery workers occupational exposure interventions health hazards
下载PDF
Long range trans-Pacific transport and deposition of Asian dust aerosols 被引量:14
5
作者 HAN Yongxiang FANG Xiaomin +1 位作者 ZHAO Tianliang KANG Shichang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第4期424-428,共5页
The deposition of Asian dust aerosols during their trans-Pacific transport might cause significant marine phytoplankton biomass increases. However, the knowledge of the trans-Pacific dust transport, deposition, and sp... The deposition of Asian dust aerosols during their trans-Pacific transport might cause significant marine phytoplankton biomass increases. However, the knowledge of the trans-Pacific dust transport, deposition, and spatial distribution is still poor due to a lack of continuous and simultaneous observations in the Asian subcontinent, the north Pacific Ocean, and North America. The severe Asian dust storm during 6 to 9 April 2001 provided an opportunity to gain a better understanding of trans-Pacific dust transport and deposition, using a comprehensive set of observations from satellites, ground-based light detection and ranging, aircraft, and surface observation networks. The observations and model simulations outline the general pattern of dust transport, deposition, vertical profile, and spatial distribution. The following points were observed: (1) the surface dust concentrations decreased exponentially with the increasing dust transport distance from 80°E to 120°W along the transport pathway; (2) the altitude of the dust concentration peak increased with increasing transport distance in the north Pacific region; and (3) the spatial distribution of dust deposition mainly depended on the trans-Pacific transport route. 展开更多
关键词 dust aerosol trans-Pacific dust transport and deposition spatial distribution
下载PDF
The Impacts of Optical Properties on Radiative Forcing Due to Dust Aerosol 被引量:10
6
作者 王宏 石广玉 +3 位作者 李书严 李伟 王标 黄彦彬 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2006年第3期431-441,共11页
There are large uncertainties in the quantitative assessment of radiative effects due to atmospheric dust aerosol. The optical properties contribute much to those uncertainties. The authors perform several sensitivity... There are large uncertainties in the quantitative assessment of radiative effects due to atmospheric dust aerosol. The optical properties contribute much to those uncertainties. The authors perform several sensitivity experiments to estimate the impacts of optical characteristics on regional radiative forcing in this paper. The experiments involve in refractive indices, single scattering aibedo, asymmetry factor and optical depth. An updated dataset of refractive indices representing East Asian dust and the one recommended by the World Meteorology Organization (WMO) are contrastively analyzed and used. A radiative transfer code for solar and thermal infrared radiation with detailed aerosol parameterization is employed. The strongest emphasis is on the refractive indices since other optical parameters strongly depend on it, and the authors found a strong sensitivity of radiative forcing on refractive indices. Studies show stronger scattering, weaker absorption and forward scattering of the East Asian dust particles at solar wavelengths, which leads to higher negative forcing, lower positive forcing and bigger net forcing at the top of the atmosphere (TOA) than that of the WMO dust model. It is also found that the TOA forcings resulting from these two dust models have opposite signs in certain regions, which implies the importance of accurate measurements of optical properties in the quantitative estimation of radiative forcing. 展开更多
关键词 optical properties dust aerosol radiative forcing
下载PDF
Vertical distribution characteristics of dust aerosol mass concentration in the Taklimakan Desert hinterland 被引量:3
7
作者 XinChun Liu YuTing Zhong +3 位作者 Qing He XingHua Yang Ali Mamtimin Wen Huo 《Research in Cold and Arid Regions》 CSCD 2013年第6期745-754,共10页
The different height mass concentrations of dust aerosol data from the atmosphere environment observation station (Ta- zhong Station) was continuously observed by instruments of Grimm 1.108, Thermo RP 1400a and TSP ... The different height mass concentrations of dust aerosol data from the atmosphere environment observation station (Ta- zhong Station) was continuously observed by instruments of Grimm 1.108, Thermo RP 1400a and TSP from January of 2009 to February of 2010 in the Taklimakan Desert hinterland. Results show that: (1) The mass concentration value of 80 m PMl0 was higher, but PM2.5 and PM1.0 concentrations at 80 m was obviously lower than 4 m PMl0, and the value of 80 m PM1.0 mass concentration was the lowest. (2) The PM mass concentrations gradually decreased from night to sunrise, with the lowest concentration at 08:00, with the mass concentration gradually increased, up to the highest concentration around 18:00, and then decreased again. It was exactly the same with the changes of wind speed. (3) The high monthly average mass concentration of TSP mainly appeared from March to September, and the highest concentration was in April and May, subsequently gradually decreased. Also, March-September was a period with high value area of PM monthly average mass concentration, with the highest monthly average mass concentration of 846.0 p.g/m3 for 4 m PM^0 appeared in May. The concentration of PM10 was much higher than those of PM2.5 and PM1.0 at 80 m. There is a small difference between the concentration of PM2.5 and PM~ 0. Dust weather was the main factor which influenced the concentration content of the different diameter dust aerosol, and the more dust weather days, the higher content of coarse particle, conversely, fine particle was more. (4) The mass concentration of different diameter aerosols had the following sequence during dust weather: clear day 〈 blowing dust 〈 floating and blowing dust 〈 sandstorm. In different dust weather, the value of PM^o/TSP in fine weather was higher than that in floating weather, and much higher than those in blowing dust and sandstorm weather. (5) During the dust weather process, dust aerosol concentration gradually decreased with particle size decreasing. The dust aerosol mass concentration at different heights and diameter would have a peak value area every 3-4 days according to the strengthening process of dust weather. 展开更多
关键词 dust aerosol dust weather mass concentration vertical distribution Taklimakan Desert
下载PDF
Direct Climatic Effect of Dust Aerosol in the NCAR Community Atmosphere Model Version 3 (CAM3) 被引量:3
8
作者 乐旭 王会军 +1 位作者 廖宏 范可 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2010年第2期230-242,共13页
Direct climate responses to dust shortwave and longwave radiative forcing (RF) are studied using the NCAR Community Atmosphere Model Version 3 (CAM3). The simulated RF at the top of the atmosphere (TOA) is-0.45 ... Direct climate responses to dust shortwave and longwave radiative forcing (RF) are studied using the NCAR Community Atmosphere Model Version 3 (CAM3). The simulated RF at the top of the atmosphere (TOA) is-0.45 W m-2 in the solar spectrum and +0.09 W m-2 in the thermal spectrum on a global average. The magnitude of surface RF is larger than the TOA forcing, with global mean shortwave forcing of-1.76 W m-2 and longwave forcing of +0.31 W m-2 . As a result, dust aerosol causes the absorption of 1.1 W m-2 in the atmosphere. The RF of dust aerosol is predicted to lead to a surface cooling of 0.5 K over the Sahara Desert and Arabian Peninsula. In the meantime, the upper troposphere is predicted to become warmer because of the absorption by dust. These changes in temperature lead to a more stable atmosphere, which results in increases in surface humidity. The upward sensible and latent heat fluxes at the surface are reduced, largely balancing the surface energy loss caused by the backscattering and absorption of dust aerosol. Precipitation is predicted to decrease moderately on a global scale. 展开更多
关键词 dust aerosol radiative forcing direct radiative effect general circulation model
下载PDF
Lead Concentration in Hong Kong Roadside Dust after Reduction of Lead Level in Petrol 被引量:4
9
作者 G.Y.S.CHAN V.W.D.CHUI M.H.WONG 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1989年第2期131-140,共10页
Samples of roadside dust were collected from 30 sites in Hong Kong.The total concentrations of 10 metals in the samples were analyzed,and the correlation coefficients among the metal contents and the annual average da... Samples of roadside dust were collected from 30 sites in Hong Kong.The total concentrations of 10 metals in the samples were analyzed,and the correlation coefficients among the metal contents and the annual average daily traffic(AADT)in 1986 were determined.Pb was found to have a significant correlation(P<0.01)with AADT.No correlation was found between Al, Ba,Cd,Cr,Cu,Fe,Mn,Ni,and Zn with respect to AADT.A general decrease in the level of Pb in roadside dust in the past few years has been observed since the reduction in the level of lead in petrol.1989 Academic Press,Inc. 展开更多
关键词 Ho In Ba Lead Concentration in Hong Kong Roadside dust after Reduction of Lead Level in Petrol Pb
下载PDF
Simulation on the spatio-temporal distribution and emission flux of dust aerosol over East Asia in 2000-2009 被引量:3
10
作者 XingTao Su HanJie Wang +2 位作者 HengRui Tao LieShuang Liu HongFeng Zhang 《Research in Cold and Arid Regions》 CSCD 2013年第2期230-239,共10页
A regional climate model (RegCM3), coupled with an online dust module, is used to simulate the spatio-temporal distribution and emission flux of dust aerosol (smaller than 20 Wn in diameter) over East Asia in the ... A regional climate model (RegCM3), coupled with an online dust module, is used to simulate the spatio-temporal distribution and emission flux of dust aerosol (smaller than 20 Wn in diameter) over East Asia in the period from 2000 to 2009. The model perfor- mance is firstly evaluated against available observations. Simulation results show that the model can capture the characteristics of spa- tio-temporal distribution of dust aerosol very well over East Asia. There always exist two extremes of dust aerosol optical depth (AOD) and column burden (CB), one is in the Taklimakan Desert of Xinjiang Uygur Autonomous Region, China, and the other is in the Ba- dain Jaran Desert of Inner Mongolian Autonomous Region, China. The maximum value of CB appears in spring, secondary maxi- mum in winter and minimum in autumn. To the east of 110°E, dust is transported eastward from a maximum center at a height of 700 hPa over the East Asian continent. Dust emission sources are mainly located in the Taklimakan Desert, Badain Jaran Desert, North Qinghai-Tibetan Plateau and Southwest Mongolia. There is also an obvious seasonal variation of dust emission flux (EF). Annual mean dust EF is 1,015.34 mg/(m2.d), of which 62.4% and 2.3% are re-deposited onto the East Asian continent through a dry and wet deposition process, respectively, and the remaining 35.3% is injected into the atmosphere or subject to long-range transport. 展开更多
关键词 dust aerosol REGCM3 column burden emission DEPOSITION
下载PDF
The Pollution Character Analysis and Risk Assessment for Metals in Dust and PM_(10) around Road from China 被引量:5
11
作者 CHEN Rong Hui WANG Bao Qing +1 位作者 WANG Ze Bei YAO Shu 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2015年第1期44-56,共13页
INTRODUCTION In recent years, with the gradual improvement of road construction, the rapid increase of the number of motor vehicles, vehicle emissions and the current poor vehicle performance, poor vehicle maintenance... INTRODUCTION In recent years, with the gradual improvement of road construction, the rapid increase of the number of motor vehicles, vehicle emissions and the current poor vehicle performance, poor vehicle maintenance, higher emission factor and so on, air pollution caused by the traffic issues becomes the focus of people attention. The harmful substances are gradually accumulated to atmosphere particles surrounding roads due to dust particles (soil dusts, road dusts, construction dusts), coal emissions, industrial emissions, vehicle emissions, biomass burning, secondary particles, which has a certain harmful influence to the atmosphere, soil and plants surrounding roads. 展开更多
关键词 The Pollution Character analysis and Risk assessment for Metals in dust and PM around Road from China
下载PDF
>Evaluation of dust activity and climate effects in North China
12
作者 XIAXiang-ao LIANGFeng WANGMing-xing 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第2期187-190,共4页
TOMS/AI data with nearly 20 years are utilized in the paper to evaluate dust activities in North China. Combined with simultaneous NCEP reanalysis climate data, climate effects on dust activities are assessed. The res... TOMS/AI data with nearly 20 years are utilized in the paper to evaluate dust activities in North China. Combined with simultaneous NCEP reanalysis climate data, climate effects on dust activities are assessed. The results showed that the whole North China suffers impact by dust aerosols, with three centers standing out in TOMS/AI spring average map that are western three basins, which are characterized by lower annual precipitation and elevation. Gobi deserts in Mongolia Plateau do not attain higher TOMS/AI value due to cloud contamination and relative higher elevation. Spring is the season with the highest TOMS dust aerosol index; within the western three basins, high dust aerosol index appears in both spring and summer, especially in Tarim Basin. Wind speed in spring and precipitation in previous rainy season play important roles in controlling dust activities, higher wind speed and less precipitation than the normal are in favor of dust activities in spring. Temperature in spring and previous winter also affect dust activity to a certain extent, but with contrary spatial distribution. Temperature in winter exert effect principally in west part, contrarily, temperature effect in spring is mainly shown in east part. Both of them have negative correlation with dust activity. 展开更多
关键词 TOMS/aI NCEP climate data dust activity correlation analysis
下载PDF
Impact of Dust Aerosol on Glacial–Interglacial Climate
13
作者 刘玉芝 石广玉 谢永坤 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第6期1725-1731,共7页
The temperature anomaly and dust concentrations recorded from central Antarctic ice core records display a strong negative correlation. The dust concentration recorded from an ice core in central Antarctica is 50-70 t... The temperature anomaly and dust concentrations recorded from central Antarctic ice core records display a strong negative correlation. The dust concentration recorded from an ice core in central Antarctica is 50-70 times higher during glacial periods than interglacial periods. This study investigated the impact of dust aerosol on glacial-interglacial climate, using a zonal energy balance model and dust concentration data from an Antarctica ice core. Two important effects of dust, the direct radiative effect and dust-albedo feedback, were considered. On the one hand, the direct radiative effect of dust significantly cooled the climate during the glacial period, with cooling during the last glacial maximum being as much as 2.05℃ in Antarctica. On the other hand, dust deposition onto the ice decreased the surface albedo over Antarctica, leading to increased absorption of solar radiation, inducing a positive feedback that warmed the region by as much as about 0.9℃ during the glacial period. However, cooling by the direct dust effect was found to be the controlling effect for the glacial climate and may be the major influence on the strong negative correlation between temperature and dust concentration during glacial periods. 展开更多
关键词 dust aerosol glacial interglacial energy balance model
下载PDF
Nonplanar dust acoustic solitary and rogue waves in an ion beam plasma with superthermal electrons and ions
14
作者 nimardeep kaur kuldeep singh +1 位作者 yashika ghai n s saini 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第7期64-71,共8页
The propagation characteristics of dust acoustic solitary and rogue waves are investigated in an unmagnetized ion beam plasma with electrons and ions following kappa-type distribution in nonplanar geometry. The reduct... The propagation characteristics of dust acoustic solitary and rogue waves are investigated in an unmagnetized ion beam plasma with electrons and ions following kappa-type distribution in nonplanar geometry. The reductive perturbation method (RPM) is employed to derive the cylindrical/spherical Korteweg-de Vries (KdV) equation, which is further transformed into standard KdV equation by neglecting the geometrical effects. Using new stretching coordinates, nonlinear Schrrdinger equation (NLSE) has been derived from the standard KdV equation to study the different order rational solutions of dust acoustic rogue waves (DARWs). The impact of various physical parameters on the characteristics of dust acoustic solitary waves (DASWs) is elaborated specifically in nonplanar geometry. Further, the effects of ion beam and superthermality of electrons/ions on the characteristics of DARWs are studied. The results obtained in the present investigation may be useful in comprehending a variety of phenomena in Earth's magnetosphere polar cap region where the presence of positive ion beam has been detected and also in other regions of space/astrophysical environments where dust along with superthermal electrons and ions exists. 展开更多
关键词 dust acoustic ion beam kappa distribution rogue waves
下载PDF
Dust acoustic waves in collisional uniform dense magnetoplasma
15
作者 杨建荣 徐婷 +2 位作者 毛杰键 刘萍 刘希忠 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第1期298-303,共6页
In order to study the characteristics of dust acoustic waves in a uniform dense dusty magnetoplasma system, a nonlinear dynamical equation is deduced using the quantum hydrodynamic model to account for dust–neutral c... In order to study the characteristics of dust acoustic waves in a uniform dense dusty magnetoplasma system, a nonlinear dynamical equation is deduced using the quantum hydrodynamic model to account for dust–neutral collisions. The linear dispersion relation indicates that the scale lengths of the system are revised by the quantum parameter, and that the wave motion decays gradually leading the system to a stable state eventually. The variations of the dispersion frequency with the dust concentration, collision frequency, and magnetic field strength are discussed. For the coherent nonlinear dust acoustic waves, new analytic solutions are obtained, and it is found that big shock waves and wide explosive waves may be easily produced in the background of high dusty density, strong magnetic field, and weak collision. The relevance of the obtained results is referred to dense dusty astrophysical circumstances. 展开更多
关键词 dusty magnetoplasma quantum hydrodynamic model dust acoustic wave
下载PDF
Nonlinear Dust Acoustic Waves in a Magnetized Dusty Plasma with Trapped and Superthermal Electrons
16
作者 S.Ahmadi ABRISHAMI M.Nouri KADIJANI 《Plasma Science and Technology》 SCIE EI CAS CSCD 2014年第6期545-551,共7页
In this work, the effects of superthermal and trapped electrons on the oblique propa- gation of nonlinear dust-acoustic waves in a magnetized dusty (complex) plasma are investigated. The dynamic of electrons is simu... In this work, the effects of superthermal and trapped electrons on the oblique propa- gation of nonlinear dust-acoustic waves in a magnetized dusty (complex) plasma are investigated. The dynamic of electrons is simulated by the generalized Lorentzian (k) distribution function (DF). The dust grains are cold and their dynamics are simulated by hydrodynamic equations. Using the standard reductive perturbation technique (RPT) a nonlinear modified Korteweg-de Vries (mKdV) equation is derived. Two types of solitary waves; fast and slow dust acoustic solitons, exist in this plasma. Calculations reveal that compressive solitary structures are likely to propagate in this plasma where dust grains are negatively (or positively) charged. The properties of dust acoustic solitons (DASs) are also investigated numerically. 展开更多
关键词 dust acoustic wave trapped electrons superthermal electrons kappa distribution function
下载PDF
Dispersion relation of dust acoustic waves in metallic multi-walled carbon nanotubes
17
作者 Ali Fathalian Shahram Nikjo 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期607-611,共5页
In this paper,a charged multi-walled carbon nanotube(MWCNT),which is surrounded by charged nanoparticles,is modeled as a cylindrical shell of electron-ion-dust plasma.By employing classical electrodynamics formulati... In this paper,a charged multi-walled carbon nanotube(MWCNT),which is surrounded by charged nanoparticles,is modeled as a cylindrical shell of electron-ion-dust plasma.By employing classical electrodynamics formulations and the linearized hydrodynamic model,the dispersion relation of the dust acoustic wave oscillations in the composed system is investigated.We obtain a new low-frequency electrostatic excitation in the MWCNT,i.e.dust acoustic wave oscillations. 展开更多
关键词 dust acoustic wave dispersion relation
下载PDF
The Chromosomal Effect of Birchen Dust as Determined by the Micronucleus Test
18
作者 JIANG ZHI-CHENG SU YI-LAN +5 位作者 DENG YI-FU SUN WEI LIU WEI-CHENG WEI DAI-MING YAN JIU-YEN YAO YU-LONGn(Deprtment of Occupotional Health, Chpital University ofMedical Sciences, Beijing, 100054, China)(Sanitationand Anti-ePidemic Station, tongiingcheng Fore 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1997年第4期396-401,共6页
In a wood processing factory, the measured air concentration of birchen dust was 1. 26 ±0. 41 mg/m3, and the micronucleus frequency of peripheral blood lymphocytes in 83 workersexposed to wood dust was 1. 13 ... In a wood processing factory, the measured air concentration of birchen dust was 1. 26 ±0. 41 mg/m3, and the micronucleus frequency of peripheral blood lymphocytes in 83 workersexposed to wood dust was 1. 13 ± 2. 83%, which was significantly higher (P < 0.01 ) thanthat of control group (0. 51 ± 1. 41% ). The number of exposed workers with positive mi-cronucleus test was 9. 6 %, which was higher than that of control group (4. 5 % ), but thedifference was not significant (P >0. 05 ). The micronucleus test in mice treated with waterextracts of unsteamed and unbaked birchen dust showed that the micronucleus frequencies inall treated groups were significantly higher than that of contro group (P < 0. 01 ) and therewas also a doseresponse correlation (r = 0. 96, P < 0. 0005 ). The results of steamed andbaked birchen dust extracts were significantly lower than those of the unsteamed and unbakedones at the same doses (P< 0. 001 ). This suggests that when the birchen dust is steamed atthe temperature of 100℃ for 24h or baked at the temperature of 80℃, its inducing effect inmicronucleus test could be lowered 展开更多
关键词 The Chromosomal Effect of Birchen dust as Determined by the Micronucleus Test CHEN
下载PDF
Characteristics of dust acoustic waves in dissipative dusty plasma in the presence of trapped electrons
19
作者 Ranjit K KALITA Manoj K DEKA +1 位作者 Apul N DEV Jnanjyoti SARMA 《Plasma Science and Technology》 SCIE EI CAS CSCD 2017年第5期21-28,共8页
The formation and propagation of nonlinear dust acoustic waves(DAWs) as solitary and solitary/shock waves in an unmagnetized, homogeneous, dissipative and collisionless dusty plasma comprising negatively charged mic... The formation and propagation of nonlinear dust acoustic waves(DAWs) as solitary and solitary/shock waves in an unmagnetized, homogeneous, dissipative and collisionless dusty plasma comprising negatively charged micron sized dust grains in the presence of free and trapped electrons with singly charged non-thermal positive ions is discussed in detail. The evolution characteristics of the solitary and shock waves are studied by deriving a modified Korteweg–de Vries–Burgers(mKdV–Burgers) equation using the reductive perturbation method. The mKdV–Burgers equation is solved considering the presence(absence) of dissipation. In the absence of dissipation the system admits a solitary wave solution, whereas in the presence of dissipation the system admits shock waves(both monotonic and oscillatory) as well as a combination of solitary and shock wave solutions. Standard methods of solving the evolution equation of shock(solitary) waves are used. The results are discussed numerically using standard values of plasma parameters. The findings may be useful for better understanding of formation and propagation of waves in astrophysical plasma. 展开更多
关键词 dust acoustic shock wave trapped electrons dissipation
下载PDF
Vertical Profile Comparison of Aerosol and Cloud Optical Properties in Dominated Dust and Smoke Regions over Africa Based on Space-Based Lidar
20
作者 Didier Ntwali Getachew Dubache Faustin Katchele Ogou 《Atmospheric and Climate Sciences》 CAS 2022年第3期588-602,共15页
This study evaluates the vertical profiles of aerosol and cloud optical properties in 40 dominated dust and smoke regions in Western-Northern Africa (WNA) and Central-Southern Africa (CSA), respectively, from the surf... This study evaluates the vertical profiles of aerosol and cloud optical properties in 40 dominated dust and smoke regions in Western-Northern Africa (WNA) and Central-Southern Africa (CSA), respectively, from the surface to 10km and from 2008 to 2011 based on LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies). Aerosol extinction (AE), aerosol backscatter (AB), and aerosol depolarization (AD) generally increase from the surface to 1.2 km and decrease from 1.2 km to the upper layers in both WNA and CSA. AE and AB in CSA (maximum of 0.13 km<sup>-1</sup>, 0.14 km<sup>-1</sup>, 0.0021 km<sup>-1</sup>&#8231;sr<sup>-1</sup>, 0.0033 km<sup>-1</sup>&#8231;sr<sup>-1</sup>) are higher than in WNA (maximum of 0.07 km<sup>-1</sup>, 0.08 km<sup>-1</sup>, 0.0017 km<sup>-1</sup>&#8231;sr<sup>-1</sup>, 0.0015 km<sup>-1</sup>&#8231;sr<sup>-1</sup>) at 532 and 1064 nm respectively. AD in WNA (maximum of 0.25) is significantly higher than in CSA (maximum of 0.05). There is a smooth change with the height of cloud extinction and backscatter in WNA and CSA, while there is a remarkable increase of cloud depolarization with height, whereby it is high in CSA and low in WNA due to high and low fraction of cirrus respectively. Altocumulus has the highest extinction in NA (0.0139 km<sup>-1</sup>), CA (0.058 km<sup>-1</sup>), WA (0.013 km<sup>-1</sup>), while low overcast transparent (0.76 km<sup>-1</sup>) below 1 km in SA. The major findings of this study may contribute to the improvement of our understanding of aerosol-cloud interaction studies in dominated dust and smoke aerosol regions. 展开更多
关键词 Vertical Profile dust aerosols Smoke aerosols Clouds aFRICa Lidar Climatology of Vertical aerosol Structure for Space-Based Lidar Simulation Studies (LIVaS)
下载PDF
上一页 1 2 42 下一页 到第
使用帮助 返回顶部