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Close up observation and inversion of low-altitude ENA emissions during a substorm event

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Science China Earth Sciences 2019年第6期62卷 1024-1032页

作者： Li LU Susan mCKENNA-LAWLOR jan BALAZ National Space Science Center of the Chinese Academy of Sciences Space Technology Ireland Ltd. Maynooth Co.Kildare Institute of Experimental Physics

During a series of substorm events on November 12 2004, the Neutral Atom Detector Unit(NUADU) flying onboard the TC-2 spacecraft observed, close to perigee, bright low-altitude Energetic Neutral Atom(ENA) emissions from both north and south poles. Through utilizing high temporal and spatial resolution data inversion techniques we present here a global view the associated processes of energetic ion deposition and injection at the uniquely high temporal resolution of a few minutes. It is demonstrated that the ENA emissions observed came mainly from the, low-altitude, high magnetic latitude polar region. Since precipitating ions follow magnetic field lines and have more chance to produce ENA emissions through charge exchange ***, the employment of a low-orbit satellite to record at high temporal and spatial resolution ENA image data is inferred to be the best way to monitor those dynamic ring current variations that occur during geomagnetic activity.

关键词： Low-altitude ENA emissions ENA image inversion Pitch angle distribution Ion injection Ion deposition

Deep learning for the internet of things:Potential benefits and use-cases

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Digital Communications and Networks 2021年第4期7卷 526-542页

作者： Tausifa jan Saleem mohammad Ahsan Chishti Department of Computer Science and Engineering National Institute of TechnologySrinagarJ&KIndia

The massive number of sensors deployed in the Internet of Things(IoT)produce gigantic amounts of data for facilitating a wide range of *** Learning(DL)would undoubtedly play a role in generating valuable inferences from this massive volume of data and hence will assist in creating smarter *** this regard,exploring the potential of DL for IoT data analytics becomes highly *** paper begins with a concise discussion on the Deep Neural Network(DNN)and its different *** potential benefits that DL will bring to the IoT are also ***,a detailed review of DL-driven IoT use-cases is ***,this paper formulates a DL-based model for Human Activity Recognition(HAR).It carries out a performance comparison of the proposed model with other machine learning techniques to delineate the superiority of the DL model over other *** from enlightening the potential of DL in IoT applications,this paper will serve as an impetus to encourage advanced research in the realm of DL-driven IoT applications.

关键词： Internet of things(IoT) Deep learning Convolutional neural network Recurrent neural network Long short term memory

Petrogenesis of middle Triassic Volcaniclastic Rocks from Balochistan,Pakistan:Implications for the Break-Up of Gondwanaland

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Journal of Earth Science 2017年第2期28卷 218-228页

作者： Rehanul Haq Siddiqui m.Qasim jan m.Ishaq Kakar Andrew C.Kerr Abdul Salam Khan Ehsanullah Kakar Balochistan University of Information Technology Engineering and Management Seiences Quetta 87300 Pakistan National Centre of Excellence in Geology University of Peshawar Pakistan & COMSTECH Islamabad 44000 Pakistan Centre of Excellence in mineralogy University of Balochistan Quetta 87300 Pakistan School of Earth and Ocean Sciences Cardiff University Main Building Park Place Cardiff Wales CF 10 3AT UK

Basaltic volcanic conglomerates near the Wulgai village in Balochistan occur in the undivided sedimentary rock unit of the Bagh complex which is the mélange zone beneath the muslim Bagh ophiolite. The presence of middle Triassic grey radiolarian chert within the upper and lower horizon of the conglomerates suggests that the lavas, from which these conglomerates were principally derived, were eroded and re-deposited in the middle Triassic. The Wulgai conglomerate contains several textural and mineralogical varieties of volcanic rocks, such as porphyritic, glomerophyric, intersertal and vitrophyric basalts. The main minerals identified in these samples are augite, olivine, plagioclase（An35–78） leucite and nosean, with apatite ilmenite, magnetite and hematite occurring as accessory minerals. These rocks are mildly to strongly-alkaline with low mg~# and low Cr, Ni and Co contents suggesting that their parent magma had undergone considerable fractionation prior to eruption. Trace element-enriched mantle-normalized patterns with marked positive Nb anomalies are consistent with 10%–15% melting of an enriched mantle source in a within-plate tectonic setting. It is proposed that this middle Triassic intra-plate volcanism may represent mantle plume-derived melts related to the Late Triassic rifting of micro-continental blocks（including Afghan, Iran, Karakorum and Lhasa） from the northern margin of Gondwana.

关键词： middle Triassic Wulgai volcaniclastics juvenile Ceno-Tethys

Impact of agricultural landscape structure on the patterns of bird species diversity at a regional scale

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Avian Research 2023年第4期14卷 600-610页

作者： Denisa Dvorakova jan Sipos Josef Suchomel Department of Zoology FisheriesHydrobiology and ApicultureMendel University in BrnoZemedelska 161300BrnoCzech Republic

The loss of bird species diversity is a crucial problem in the European agricultural *** in the area coverage of major land cover types has been mentioned as one of the main factors responsible for bird biodiversity *** this study,we focused on the impact of landscape matrix characteristics on bird species richness and on Faith’s phylogenetic diversity index on a spatial scale of 1000-m radius around the measured occurrence *** investigated how land cover composition affects bird diversity on the landscape scale using nationwide citizen science *** total,168,739 records of bird occurrence in the South moravian Region of the Czech Republic during growing season from 2009 to 2019 were *** found that the presence of water bodies and wetlands significantly corresponded to the areas of highest bird species *** also revealed that the presence of forests(~60%of the forest in the Czech Republic is occupied by commercial forests),urban areas and arable land were negatively associated with bird species richness and phylogenetic ***(both coniferous and deciduous)and urban habitats were found to have a tendency to host a clustered phylogenetic community structure in comparison with wetland and arable land.A strong negative association between forest proportion and bird diversity led us to conclude that the expansion of the forest(with simple species composition,horizontal and vertical structure)could be one of the critical drivers of the decline of bird species diversity in the European agricultural *** the other hand,our results also pointed out that small woody features(i.e.,woodlots)and scattered woodland shrub vegetation were one of the main landscape characteristics supporting a bird diversity in rural *** is in concordance with other studies which mention these landscape structures as important elements for nesting and foraging of farmland *** thus recommend to maintain and restor

关键词： Bird occurrence Citizen science Conservation Landscape influence Phylogenetic diversity Spatial heterogeneity

Establishing simulation model for optimizing efficiency of CNC machine using reliability-centered maintenance approach

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International Journal of modeling, Simulation, and Scientific Computing 2019年第6期10卷 1-14页

作者： Zahid Hussain Hamid jan Sarhad University of Science and Information Technology Peshawar 25000Pakistan

The objective of this work was to enhance the product’s quality by concentrating on the machine’s optimized *** order to increase the machine’s reliability,the basis of reliability-centered maintenance approach was *** purpose was to establish a planned preventive maintenance strategy to identify the machine’s critical components having a noteworthy effect on the product’s *** critical components were prioritized using failure mode and effect analysis(FmEA).The goal of the study was to decrease the ppm time interval for a CNC machine by simulating the projected preventive maintenance time *** this purpose,the simulation software Promodel 7.5 was implemented for the current preventive maintenance procedure to choose the best ppm time interval which contributed better *** dissimilar optimization approaches were applied,however,the first approach yielded the prominent total system cost and the shorter ppm *** results of the study revealed that there was an increase of USD 1878 as a result of an increase in total system cost from USD 78,365 to USD 80,*** maintenance costs were reduced from USD 4196 to USD 2248(46%).The costs associated with good parts increased from USD 8259 to USD 8294(0.4%)and the costs associated with defective parts reduced from USD 171 to USD 3(98.25%),respectively.

关键词： Simulation model CNC machine reliability-centered maintenance(RCm) failure mode and effect analysis(FmEA) planned preventive maintenance

Weak influence of natural vegetation in urban green spaces compared to agricultural ecosystems on House martin populations:Insights from nationwide citizen science data in the Czech Republic

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Avian Research 2024年第2期15卷 139-146页

作者： Denisa Dvorakova jan Sipos Josef Suchomel Department of Zoology FisheriesHydrobiology and ApicultureMendel University in BrnoZemedelska 161300BrnoCzech Republic

The House martin(Delichon urbicum)is a common farmland bird species in the European landscape,yet its population numbers are currently in ***,it is not yet sufficiently explained why this long-term decline *** fill this gap in our knowledge,we investigated how land cover composition affects the abundance of House martins on the landscape scale by using nationwide citizen science *** a generalised linear mixed-effect model(GLmm),we evaluated 12,094 records from the Czech Republic spanning *** analysis underscores the significance of land cover type in shaping House martin *** specifically,our results indicate that within agricultural land covers“naturally managed arable lands”exhibited significant positive effect,while forests,orchards,and vineyards were deemed less favourable for House martin *** urban land covers,we found a clear distinction in the impact on House martin populations,with a positive effect observed in urban infrastructure,development areas,and post-industrial sites(i.e.,UrbanAreas),while an indifferent impact was noted within urban green spaces and landscaped areas(i.e.,GreenUrban).Notably,our findings suggest that the simple spatial,age,and species structure typical of forests in Europe,and similarly,the uniform structure of parks and gardens,may be responsible for the decline in the abundance of the House *** advocate for the preservation or enhancement of urban greenery,expansion of natural vegetation in rural areas and adoption of ecological management practices in orchards and vineyards to mitigate further declines in House martin populations.

关键词： Citizen science Habitat preferences House martin Species distribution Urban and suburban landscape

Effects of acid deposition control in China:a review based on responses of subtropical forests

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Frontiers of Environmental Science & Engineering 2024年第6期18卷 115-126页

作者： Danni Xie Xiaodong Ge Lei Duan jan mulder School of Land Engineering Chang’an UniversityXi’an 710064China State Key Laboratory of Environmental Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084China Faculty of Environmental Sciences and Natural Resource management Norwegian University of Life SciencesBox 5003NO-1432ÅsNorway

For many decades,acid deposition used to pose a significant regional air pollution challenge in *** substantial emission control of anthropogenically derived sulfur and nitrogen containing gasses,both sulfur and nitrogen deposition,as well as the acid rain-affected area,have significantly decreased compared to their peak ***,particularly in the humid subtropics,are sensitive to acid deposition,as evidenced by soil acidification,sulfate and nitrate leaching in stream water,and elevated soil nitrous oxide *** in the total deposition of sulfur and nitrogen,caused a significant decline in sulfate and nitrate leaching from subtropical forest and subsequently in sulfate and nitrate concentrations in stream water,although there was about a 5-year *** delay may be attributed to the desorption of accumulated sulfate and continued elevated mineralization of accumulated nitrogen *** of nitrous oxide,a potent greenhouse gas,also declined in nitrogen-saturated subtropical forest soils,as soil water nitrate concentration ***,subtropical forests in China suffering from elevated acid deposition have begun to ***,the current levels of sulfur and nitrogen deposition continue to exceed the critical loads,i.e.,the assigned threshold levels in accordance with emission control policies,in more than 10%of the country’s land area,respectively,indicating remaining risks of acidification and ***,further emission reductions are urgently needed,also because they will help achieving goals related to air quality and nitrous oxide emissions.

关键词： Acidification Critical load Nitrous oxide Surface water chemistry Recovery

Solid Bi_(2)O_(3)-derived nanostructured metallic bismuth with high formate selectivity for the electrocatalytic reduction of CO_(2)

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International Journal of minerals,metallurgy and materials 2024年第4期31卷 803-811页

作者： Xiaoyan Wang Safeer jan Zhiyong Wang Xianbo Jin College of Chemistry and molecular Sciences Hubei Key Laboratory of Electrochemical Power SourcesWuhan UniversityWuhan 430072China Engineering Research Center of Organosilicon Compounds&materials Ministry of EducationWuhan 430072China

CO_(2) electrochemical reduction(CO_(2)ER)is an important research area for carbon ***,available catalysts for CO_(2) reduction are still characterized by limited stability and ***,metallic bismuth(Bi)has emerged as a promising catalyst for CO_(2) ***,we report the solid cathode electroreduction of commercial micronized Bi2O3as a straightforward approach for the preparation of nanostructured ***-1.1 V versus reversible hydrogen electrode in a KHCO3aqueous electrolyte,the resulting nanostructure Bi delivers a formate current density of~40 mA·cm^(-2) with a current efficiency of~86%,and the formate selectivity reaches97.6% at-0.78 *** nanosized Bi2O3as the precursor can further reduce the primary particle sizes of the resulting Bi,leading to a significantly increased formate selectivity at relatively low *** high catalytic activity of nanostructured Bi is attributable to the ultrafine and interconnected Bi nanoparticles in the nanoporous structure,which exposes abundant active sites for CO_(2) electrocatalytic reduction.

关键词： bismuth carbon dioxide electrocatalysis formate solid electroreduction

Impact of atmospheric turbulence on coherent beam combining for laser weapon systems

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Defence Technology（防务技术） 2021年第4期17卷 1160-1167页

作者： jan K.Jabczyński Przemysław Gontar military University of Technology Gen.S.Kaliskiego 2Warsaw00-908Poland

The performance of a laser weapon system based on coherent beam combining(CBC)depends on its propagation properties in the *** this study,an analytical model based on partial coherent beam combining(PCBC)for assumed coherence coefficients between beams in a CBC lattice was *** Kolmogorov model of atmospheric turbulence and the Hufnagel-Valley model of C^(2)_(n) dependence on atmospheric parameters were *** simplified metrics were proposed to assess the CBC *** beam profiles(super-Gaussian,truncated Gaussian,etc.)and geometries were analyzed in terms of maximal intensity in the far *** approximate formula for PCBC efficiency dependent on the Fried radius was *** results of CBC modeling were compared to those of the Gaussian beam propagation model in a turbulent *** dependence of CBC performance on the C^(2)_(n) parameter,range,and elevation angle was *** could be concluded that the application of CBC for medium and long range propagation is impractical without an effective adaptive optics system.

关键词： Laser beams Beam combining Coherence Atmosphere turbulences