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Distribution and mapping of temperate savanna in the sandy lands of eastern China

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Science China Earth Sciences 2025年第1期 128-141页

作者： Xiaoya LI Feng WANG Tao DUAN Kaijie YANG Bin YANG Chunmei WANG Xin TIAN Qi LU Institute of Ecological Conservation and Restoration Institute of Desertification Studies Chinese Academy of Forestry Institute of Desertification Institute of Desertification Studies Chinese Academy of Forestry Institute of Great Green Wall Satellite Application centre for Ecology and Environment MEE Institute of Microelectronics Chinese Academy of Sciences Aerospace Information Research Institute Chinese Academy of Sciences Institute of Forest Resource Information Techniques Chinese Academy of Forestry

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution （VHR） unmanned aerial vehicle （UAV） and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover （FWVC） and fractional herbaceous vegetation cover （FHVC） in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error （RMSE） values for the FWVC and FHVC models were 10.69% and 11.67%,and the R2values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10～6 *** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy

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Tweezing and manipulating micro- and nanoparticles by optical nonlinear endoscopy

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Light(Science & Applications) 2014年第1期3卷 377-382页

作者： Min Gu Hongchun Bao Xiaosong Gan Nicholas Stokes Jingzhi Wu centre for Micro-Photonics Faculty of Engineering&Industrial SciencesSwinburne University of TechnologyHawthornVic.3122Australia

The precise control and manipulation of micro-and nanoparticles using an optical endoscope are potentially important in biomedical studies,bedside diagnosis and treatment in an aquatic internal organ environment,but they have not yet been ***,for the first time,we demonstrate optical nonlinear endoscopic tweezers(ONETs)for directly controlling and manipulating aquatic micro-and nanobeads as well as gold *** is found that two-photon absorption can enhance the trapping force on fluorescent nanobeads by up to four orders of magnitude compared with dielectric nanobeads of the same *** importantly,two-photon excitation leads to a plasmon-mediated optothermal attracting force on nanorods,which can extend far beyond the focal *** new phenomenon facilitates a snowball effect that allows the fast uploading of nanorods to a targeted cell followed by thermal treatment within 1 *** two-photon absorption allows an operation wavelength at the center of the transmission window of human tissue,our work demonstrates that ONET is potentially an unprecedented tool for precisely specifying the location and dosage of drug particles and for rapidly uploading metallic nanoparticles to individual cancer cells for treatment.

关键词： endoscopy gold nanorods micro/nanotweezing two-photon absorption

Hydrocarbons in particulate samples from wildfire events in central Portugal in summer 2010

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Journal of Environmental Sciences 2017年第3期29卷 122-131页

作者： Ana Vicente Ana Calvo Ana P.Fernandes Teresa Nunes Cristina Monteiro Casimiro Pio Célia Alves centre for Environmental and Marine studies (CESAM) Department of EnvironmentUniversity of Aveiro Department of Physics IMARENABUniversity of León

In summer 2010, twenty eight （14 PM=2.5 samples plus 14 samples PM2.5-10） smoke samples were collected during wildfires that occurred in central Portugal. A portable high-volume sampler was used to perform the sampling, on quartz fibre filters of coarse （PM=2.5-10） and fine （PM2.5） smoke samples. The carbonaceous content （elemental and organic carbon） of particulate matter was analysed by a thermal-optical technique. Subsequently, the particulate samples were solvent extracted and fractionated by vacuum flash chromatog- raphy into three different classes of organic compounds （aliphatics, polycyclic aromatic hydrocarbons （PAHs） and carbonyl compounds）. The organic speciation was performed by gas chromatography-mass spectrometry （GC-MS）. Emissions were dominated by the fine particles, which represented around 92% of the PM10. A clear predominance of carbonaceous constituents was observed, with organic to elemental carbon （OC/EC） ratios ranging between 1.69 and 245 in both size fractions. The isoprenoid ketone 6,10,14-trimethyl-2-pentadecanone, a tracer for secondary organic aerosol formation, was one of the dominant constituents in both fine and coarse particles. Retene was the most abundant compound in all samples. Good correlations were obtained between OC and both aliphatic and PAH compounds. Pyrogenic processes, thermal release of biogenic com- pounds and secondary processing accounted for 97% of the apportioned PM2.5 levels.

关键词： WildfiresOrganic carbonOrganic compoundsBiomarkersParticulate matterPortugal

Generation and Application of a Luciferase Reporter Virus Based on Yellow Fever Virus 17D

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Virologica Sinica 2021年第6期36卷 1456-1464页

作者： Dan Li Jing-Long Ye Zhong-Yu Liu The centre for Infection and Immunity studies School of MedicineSun Yat-Sen UniversityGuangzhou 510006China

Yellow fever virus(YFV) is a re-emerging virus that can cause life-threatening yellow fever disease in *** the availability of an effective vaccine,little is known about the replication mechanism of YFV,and there are still no available specific anti-YFV ***,by introducing the Renilla luciferase gene(Rluc) into an infectious clone of YFV vaccine strain 17 D,we generated a recombinant virus 17 D-Rluc.2 A via reverse genetics *** 17 D-Rluc.2 A had similar plaque morphology and comparable in vitro growth characteristics with its parental ***,the reporter luciferase was efficiently expressed in 17 D-Rluc.2 A-infected mammalian and mosquito cells,and there was a good linear correlation between intracellular luciferase expression and extracellular infectious virion ***,by a combination of the 17 D-Rluc.2 A reporter virus and selective 2’-hydroxyl acylation analyzed by primer extension(SHAPE)technology,the conserved 5’-SLA element was shown to be essential for YFV replication,highlighting the capability of17 D-R1 uc.2 A in the investigation of YFV *** last,we demonstrated that two compounds with distinct anti-viral mechanisms can effectively inhibit the viral propagation in 17 D-Rluc.2 A-infected cells,demonstrating its potential application in the evaluation of anti-viral *** together,the 17 D-Rluc.2 A serves as a useful tool for the study of YFV replication and anti-YFV medicine development.

关键词： Yellow fever virus(YFV) 17D Reporter virus Cis-acting RNA elements Anti-viral medicines

Climate pledges versus commitment: Are policy actions of Middle-East and North African countries consistent with their emissions targets?

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Advances in Climate Change Research 2022年第4期13卷 612-621页

作者： Hermas ABUDU Presley K.WESSEH Jr Boqiang LIN School of Management China Institute for Studies in Energy PolicyCollaborative Innovation Center for Energy Economics and Energy PolicyXiamen UniversityFujian361005China Belt and Road Research Institute Xiamen UniversityFujian361005China

Carbon emission is inevitable,and changes with energy consumption and economic development,presents policy options toward sustainable development ***,there is little assurance from policymakers in committing to climate change pledges:taking the Middle-East and North African(MENA)region as a specific case with using 2019 as a cut-off *** conducted an interim assessment of the Paris Agreement to ascertain whether climate actions are in tandem with emissions reduction *** use of difference-in-difference technique as a quasiexperiment supported by fixed-effects and placebo treatment models,the results point to evidence of less than 1%effective CO_(2) emissions reduction as of 2019 compared to the 2015 *** current carbon emissions reduction commitment level is far-reaching contrary to the Nationally Determined Contributions(NDCs)pledged(16.43%on average by 2030 compared to the 2015 level).The analysis suggests that achieving NDCs commitments are currently major burden on policymakers since the economic development is highly linked with nonrenewable energy ***,a more comprehensive framework when accounting for all available renewable and clean energy projects shows reduction levels in the range of 30%-40%from 2020 to *** results suggest that the Paris Agreement in MENA countries may be more effective from 2020,thus underscore the importance of capturing ongoing projects(involving renewable and clean energy technologies)into interim policy *** shared implication is that greater efforts are demanded from the region and at country levels to further decrease emissions through the use of negative emissions technologies particularly in the electricity generation sector.

关键词： Paris Agreement Carbon emissions reduction potential Carbon effciency:Climate change policy quasi-experiment MENA climate change performance

Analysis of the Statistical Behaviour of Daily Maximumand Monthly Rainfall Data at New DelhiDuring Monsoon Period

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Advances in Atmospheric Sciences 2002年第3期19卷 425-432页

作者： C. V. Singh R. S. Adhikari H. P. Garg centre of Energy studies Indian Institute of Technology Hauz Khas 110 016 New Delhi India

A statistical analysis of monthly mean and daily maximum rainfall data at New Delhi during the mon-soon (June-September) period 1940-1980 is presented. It has been observed that a good correlation exists between the monthly and daily maximum rainfall. A linear regression analysis of the data is found to be sig nificant for all the four months. Some key statistical parameters like the mean values of Coefficient of Vari ability (CV), Relative Variability (RV) and Percentage Interannual Variability (PIV) have been studied and found to be at variance. However, their corresponding ratios between mean daily maximum and mean monthly rainfall are significantly lower.

关键词： Monsoon rainfall Coefficient of variability Relative variability Percentage interannual varia-bility

MHD flow and heat transfer of micropolar fluid between two porous disks

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Applied Mathematics and Mechanics(English Edition) 2012年第1期33卷 51-64页

作者： M. ASHRAF A. R. WEHGAL centre for Advanced studies in Pure and Applied Mathematics Bahauddin Zakariya University Department of Mathematics Stockholm University

A numerical study is carried out for the axisymmetric steady laminar incompressible flow of an electrically conducting micropolar fluid between two infinite parallel porous disks with the constant uniform injection through the surface of the disks. The fluid is subjected to an external transverse magnetic field. The governing nonlinear equations of motion are transformed into a dimensionless form through yon Karman＇s similarity transformation. An algorithm based on a finite difference scheme is used to solve the reduced coupled ordinary differential equations under associated boundary conditions. The effects of the Reynolds number, the magnetic parameter, the micropolar parameter, and the Prandtl number on the flow velocity and temperature distributions are discussed. The results agree well with those of the previously published work for special cases. The investigation predicts that the heat transfer rate at the surfaces of the disks increases with the increases in the Reynolds number, the magnetic parameter, and the Prandtl number. The shear stresses decrease with the increase in the injection while increase with the increase in the applied magnetic field. The shear stress factor is lower for micropolar fluids than for Newtonian fluids, which may be beneficial in the flow and thermal control in the polymeric processing.

关键词： MHD flow porous disk micropolar fluid heat transfer microrotation

China's Regional Disparity and Its policy Responses

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China & World Economy 2008年第4期16卷 16-32页

作者： Minjia Chen Yongnian Zheng Research Associate China Policy Institute School of Contemporary Chinese Studies University of Nottingham Nottingham UK Professor China Policy Institute School of Contemporary Chinese Studies University of Nottingham Nottingham UK

The fruits of China＇s rapid economic development over the 3 decades have not been distributed fairly across different regions. Using data from a sample of 815 Chinese listed firrns during 1998-2004, our error-correction investment model showes evidence of different financial constraints on firms＇ investment in different regions. We argue that China＇s regional development policies have contributed greatly to the regional inequalities. To control the rising inequality, China has shifted its focus from the coast to the interior regions. However, it is becoming increasingly difficult for the government to direct the economy, as market mechanisms now have afar greater influence on the economy than the government does. The people-centered approach of the current leadership has meant that substantial attention has been placed on regional development disparities in an attempt to build a ＂harmonious society. ＂ China needs further extensive reforms if all the measures for reducing regional disparity are to be effective.

关键词： China development policy error-correction model regional inequality

Nitrogen Mineralization in Soils Along a Vegetation Chronosequence in Hong Kong

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Pedosphere 2005年第2期15卷 181-188页

作者： L.M.MARAFA K.C.CHAU centre for Environmental policy and Resource Management Centre for Environmental Policy and Resource Management Department of Geography and Resource ManagementThe Chinese University of Hong KongShatinNew TerritoriesHong Kong (China)Department of Geography and Resource ManagementThe Chinese University of Hong KongShatinNew TerritoriesHong Kong (China)

This research examined nitrogen mineralization in the top 10 cm of soils along a vegetation gradient in Hong Kong at sites where fire has been absent for 0, 1, 3, 6 and 17 years (at the time of the study), and the relationships between N mineralization and successional development of vegetation in the absence of fire. The sites including a newly burnt area (S1), short grassland (S2), tall grassland (S3), mixed tall grassland and shrubland (S4), and woodland (S5) were selected,and the in situ core incubation method was used to estimate nitrogen mineralization. Throughout the 60-day incubation in four periods, more nitrogen was mineralized at the S3 and S4 sites, the predominantly grassland sites, which contained the highest levels of soil organic matter (SOM) and total Kjeldahl nitrogen (TKN), than the S1 site, while immobilization occurred at the S2 and S5 sites. Leaching loss decreased with successional development of the vegetation, in the order of S1 ＞ S2 ＞ S3 ＞ S4 ＞ S5. The pattern of nitrogen uptake with ecological succession was less conspicuous, being complicated by the immediate effect of fire and possibly the ability of the woodland species to extract nitrogen from the deeper *** the absence of fire for 3 to 6 years, the build-up of SOM and TKN was accompanied by active mineralization, thus paving the way for the invasion of shrub and tree species. A close relationship existed between nitrogen mineralization and ecological succession with this vegetation gradient. Inherent mechanisms to preserve nitrogen in a fire-prone environment including immobilization and uptake and the practical relevance of nitrogen mineralization to reforestation are discussed.

关键词： fire impact immobilization nitrogen mineralization successional development vegetation chronosequence