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Mapping of moraine dammed glacial lakes and assessment of their areal changes in the central and eastern Himalayas using satellite data

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Journal of Mountain Science 2019年第1期16卷 77-94页

作者： Sazeda BEGAM Dhrubajyoti sen School of Water Resources Indian Institute of Technology Kharagpur Department of Civil Engineering Indian Institute of Technology Kharagpur

The relatively rapid recession of glaciers in the Himalayas and formation of moraine dammed glacial lakes(MDGLs) in the recent past have increased the risk of glacier lake outburst floods(GLOF) in the countries of Nepal and Bhutan and in the mountainous territory of Sikkim in India. As a product of climate change and global warming, such a risk has not only raised the level of threats to the habitation and infrastructure of the region, but has also contributed to the worsening of the balance of the unique ecosystem that exists in this domain that sustains several of the highest mountain peaks of the world. This study attempts to present an up to date mapping of the MDGLs in the central and eastern Himalayan regions using remote sensing data, with an objective to analyse their surface area variations with time from 1990 through 2015, disaggregated over six episodes. The study also includes the evaluation for susceptibility of MDGLs to GLOF with the least criteria decision analysis(LCDA). Forty two major MDGLs, each having a lake surface area greater than 0.2 km2, that were identified in the Himalayan ranges of Nepal, Bhutan, and Sikkim, have been categorized according to their surface area expansion rates in space and time. The lakes have been identified as located within the elevation range of 3800 m and6800 m above mean sea level(a msl). With a total surface area of 37.9 km2, these MDGLs as a whole were observed to have expanded by an astonishing 43.6% in area over the 25 year period of this study. A factor is introduced to numerically sort the lakes in terms of their relative yearly expansion rates, based on their interpretation of their surface area extents from satellite imageries. Verification of predicted GLOF events in the past using this factor with the limited field data as reported in literature indicates that the present analysis may be considered a sufficiently reliable and rapid technique for assessing the potential bursting susceptibility of the MDGLs.

关键词： Glacier retreat Lakes mapping Moraine dammed glacial lake(MDGL) Surface area change of lakes Landsat imagery data Least criteria decision analysis(LCDA)

Optofluidic transport and assembly of nanoparticles using an all-dielectric quasi-BIC metasurface

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Light(Science & Applications) 2023年第9期12卷 1771-1781页

作者： sen Yang Justus C.Ndukaife Department of Electrical and Computer Engineering Vanderbilt UniversityNashvilleTNUSA Interdisciplinary Materials Science Vanderbilt UniversityNashvilleTNUSA Full list of author information is available at the end of the article

Manipulating fluids by light at the micro/nanoscale has been a long-sought-after goal for lab-on-a-chip *** heating has been demonstrated to control microfluidic dynamics due to the enhanced and confined light absorption from the intrinsic losses of ***,the counterpart of metals,has been used to avoid undesired thermal effects due to its negligible light ***,we report an innovative optofluidic system that leverages a quasi-BIC-driven all-dielectric metasurface to achieve subwavelength scale control of temperature and fluid *** experiments show that suspended particles down to 200 nanometers can be rapidly aggregated to the center of the illuminated metasurface with a velocity of tens of micrometers per second,and up to millimeter-scale particle transport is *** strong electromagnetic field enhancement of the quasi-BIC resonance increases the flow velocity up to three times compared with the off-resonant situation by tuning the wavelength within several nanometers *** also experimentally investigate the dynamics of particle aggregation with respect to laser wavelength and power.A physical model is presented and simulated to elucidate the phenomena and surfactants are added to the nanoparticle colloid to validate the *** study demonstrates the application of the recently emerged all-dielectric thermonanophotonics in dealing with functional liquids and opens new frontiers in harnessing non-plasmonic nanophotonics to manipulate microfluidic ***,the synergistic effects of optofluidics and high-Q all-dielectric nanostructures hold enormous potential in high-sensitivity biosensing applications.

关键词： dielectric quasi negligible

Open surgical approach for two coincidental splenic artery aneurysms:a case report

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World Journal of Emergency Medicine 2023年第5期14卷 419-420页

作者： Weirong Zheng sen Li Department of Vascular Surgery the First People's Hospital of WenlingWenling 317500China Department of Vascular Surgery the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China

Several factors can contribute to the formation of aneurysms,including hemodynamic changes,polyarteritis nodosa,bacterial endocarditis,vasculitis,fibromuscular dysplasia,vascular malformation,and cystic medial necrosis.^([1,2]) Surgery is recommended for splenic artery aneurysms (SAAs) greater than 25 mm in diameter,and several surgical approaches are used,including open surgery,laparoscopic surgery,and percutaneous *** surgery might be associated with an increased risk of pancreatic leakage compared to the open surgery approach.

关键词： aneurysm Surgery surgical

PAIDD:a hybrid P2P-based architecture for improving data distribution in social networks

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Science China(Information Sciences) 2014年第4期57卷 96-106页

作者： SHUANG Kai SU sen State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications

Rapid growth in social networks(SNs)presents a unique scalability challenge for SN operators because of the massive amounts of data distribution among large number of concurrent online users.A request from any user may trigger hundreds of server activities to generate a customized page and which has already become a huge *** on the theoretical model and analytical study considering realistic network scenarios,this article proposes a hybrid P2P-based architecture called *** fulfills effective data distribution primarily through P2P connectivity and social graph among users but with the help of central *** increase system efficiency,PAIDD performs optimized content prefetching based on social interactions among *** chooses interaction as the criteria because user’s interaction graph is measured to be much smaller than the social *** experiments confirm that PAIDD ensures satisfactory user experience without incurring extensive overhead on clients’*** importantly,PAIDD can effectively achieve one order of magnitude of load reduction at central servers.

关键词： social network data distribution PAIDD hybrid P2P-based interaction-oriented

A Simple Method to Extract Tropical Monsoon Forests Using NDVI Based on MODIS Data:A Case Study in South Asia and Peninsula Southeast Asia

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Chinese Geographical Science 2016年第1期26卷 22-34页

作者： LIN sen LIU Ronggao State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Distribution of monsoon forests is important for the research of carbon and water cycles in the tropical regions. In this paper, a simple approach is proposed to map monsoon forests using the Normalized Difference Vegetation lndex （NDVI） derived from the Moderate Resolution Imaging Spectroradiometer （MODIS） data. Owing to the high contrast of greenness between wet season and dry season, the monsoon forest can be easily discriminated from other forests by combining the maximum and minimum annual NDVI. The MODIS-based monsoon forest maps （MODMF） from 2000 to 2009 are derived and evaluated using the ground-truth dataset. The MODMF achieves an average producer accuracy of 80.0% and the Kappa statistic of 0.719. The variability of MODMF among different years is compared with that calculated from MODIS land cover products （MCD 12Q 1）. The results show that the coefficient of variation of total monsoon forest area in MODMF is 7.3%, which is far lower than that in MCD12Q1 with 24.3%. Moreover, the pixels in MODMv which can be identified for 7 to 9 times between 200l and 2009 account for 53.1%, while only 7.9% ofMCD12QI pixels have this frequency. Additionally, the monsoon forest areas estimated in MODMF, Global Land Cover 2000 （GLC2000）, MCDI2Q1 and University of Maryland （UMD） products are compared with the statistical dataset at national level, which reveals that MODMv has the highest R^2 of 0.95 and the lowest RMSE of 14 014 km^2. This algorithm is simple but reliable for mapping the monsoon forests without complex classification techniques.

关键词： monsoon forest Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index(NDVI) amplitude threshold classification

3种天然阔叶混交林林木物种和大小分化多样性与地形的耦合关系

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东北林业大学学报 2025年第2期53卷 16-24页

作者：郜昌建王海龙徐森张小伟浙江省林业勘测规划设计有限公司杭州310020 浙江省森林资源监测中心

依据2021年浙江省森林资源连续清查数据,选取969个幼龄林和中林龄天然阔叶混交林样地,并依据样地植被型将样地划分为常绿阔叶林、落叶阔叶林和常绿落叶阔叶3种植被类型,采用方差分析及Pearson分析地形与林木物种和大小分化多样性的关系... 详细信息

依据2021年浙江省森林资源连续清查数据,选取969个幼龄林和中林龄天然阔叶混交林样地,并依据样地植被型将样地划分为常绿阔叶林、落叶阔叶林和常绿落叶阔叶3种植被类型,采用方差分析及Pearson分析地形与林木物种和大小分化多样性的关系。结果表明:1)3种植被类型间物种多样性指标间均呈显著差异(P<0.05),落叶阔叶林胸径变异系数和胸径均匀度显著高于常绿阔叶林(P<0.05),而常绿阔叶林胸径香农维纳指数显著高于落叶阔叶林和常绿落叶阔叶林(P<0.05);2)随海拔或坡度的升高,3种植被类型丰富度、香农维纳指数和辛普森多样性指数均显著升高(P<0.05),但落叶阔叶林和常绿落叶阔叶林Pielou均匀度指数无明显差异,坡向对林木物种多样性无明显影响;3)随海拔升高,3种植被类型胸径变异系数和胸径均匀度整体上均呈降低趋势,而胸径香农维纳指数则相反;由阳坡到阴坡,常绿阔叶林和常绿落叶阔叶林胸径均匀度指数整体上均呈升高趋势;随坡度增加,落叶阔叶林胸径变异系数和3种植被类型胸径均匀度均降低,而落叶阔叶林胸径香农维纳指数则相反。海拔和坡度对3种植被类型树种数量、胸径均匀度有明显影响,但对落叶阔叶林和常绿落叶阔叶林树种均匀度、常绿阔叶林胸径变异系数均无明显影响,而坡向主要影响常绿阔叶林和常绿落叶阔叶林胸径均匀度。

关键词：天然阔叶混交林地形物种多样性大小分化多样性

A Study on the Far Wake of Elliptic Cylinders

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Computer Modeling in Engineering & Sciences 2017年第1期113卷 35-55页

作者： Subhankar sen Sanjay Mittal Department of Mechanical Engineering Indian Institute of Technology KanpurIndia Department of Aerospace Engineering Indian Institute of Technology KanpurIndia

The evolution of far wake of stationary elliptic cylinders with angle of attack is investigated for the unsteady flow at Re=200 using a stabilized finite-element *** Reynolds number,Re,is based on the major axis of cylinder and free-stream *** aspect ratios,AR considered are 0.2,0.5 and 0.8 while the angle of attack,αvaries from 0° to 90°.With increasingα,the Karman or primary shedding frequency of each cylinder decreases monotonically while the primary wavelength and time-averaged as well as *** increase *** time-averaged lift and moment coefficients initially increase withαand then *** power spectrum analysis of unsteady transverse velocity signal at various stations along the wake centerline is used to study the associated *** Karman or primary shedding frequency exists for eachα.For the AR=0.2 cylinder,the secondary and subsequently,low magnitude tertiary frequencies appear in the wake asαcontinues to increase from 30°.In contrast to the decaying nature of primary frequency withα,secondary frequency exhibits a nonmonotonic *** secondary frequency in general is not a sub-harmonic of the *** suggests that the secondary structures do not form due to merging of primary *** increasingα,the location of formation of secondary structures advances *** a given orientation,the upstream advancement is more dominant with decreasing *** spectrum analysis indicates that the wake state for confined flow is characterized by the primary frequency alone,*** imposition of blockage suppresses the formation of secondary structures.

关键词： Elliptic cylinder stabilized finite-element far wake angle of attack blockage

Determination of trace PAHs in seawater and sediment pore-water by solid-phase microextraction (SPME) coupled with GC/MS

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Science China Chemistry 2006年第6期49卷 481-491页

作者： Lee Franck sen-Chun Material Transport & Transformation in Environmental & Life Processes Lab First Institute of Oceanography State Oceanic Administration

A fast and reliable method for the determination of trace PAHs (polynuclear aromatic hydrocarbons) in seawater by solid-phase microextraction (SPME) followed by gas chromatographic (GC) analysis has been developed. The SPME operational parameters have been optimized, and the effects of salinity and dissolved organic matter (DOM) on PAHs recoveries have been investigated. SPME measures only the portion of PAHs which are water soluble, and can be used to quantify PAH partition coefficient between water and DOM phases. The detection limits of the overall method for the measurement of sixteen PAHs range from 0.1 to 3.5 ng/g, and the precisions of individual PAH measurements range from 4% to 23% RSD. The average recovery for PAHs is 88.2±20.4%. The method has been applied to the determination of PAHs in seawater and sediment porewater samples collected in Jiaozhou Bay and Laizhou Bay in Shandong Peninsula, China. The overall levels of PAHs in these samples reflect moderate pollution compared to seawater samples reported elsewhere. The PAH distribution pattern shows that the soluble PAHs in seawater and porewater samples are dominated by naphthalenes and 3 ring PAHs. This is in direct contrast to those of the sediment samples reported earlier, in which both light and heavy PAHs are present at comparable concentrations. The absence of heavy PAHs in soluble forms (<0.1-3.5 ng/L) is indicative of the strong binding of these PAHs to the dissolved or solid matters and their low seawater solubility.

关键词： solid-phase microextraction, polycyclic aromatic hydrocarbons, dissolved organic matter, marine sediment porewater, PAH-DOM complex.

Fuzzy　Consistent　Matrix　and　Its　Application

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Journal of Systems Engineering and Electronics 1997年第1期8卷 57-64页

作者： Yao, Min Zhang, sen Hangzhou Univ China

This paper presents a kind of fuzzy consistent matrix and introduces its application in analytic hierarchy process and adaptive fuzzy reasoning.

关键词： Fuzzy consistent matrix Analytic hierarchy process Fuzzy reasoning.