简介：torevealthatdiscoursesonimmigrationarealwaysperformativediscourseswhichhelpeffectthewondroussocialalchemywherebya"foreigner"ismadeintoa"national"(Sayad1987and1994).AllthisSayadknewordiscoveredbecausehewasmorethanascholarofimmigration,yetnoneofthepartiestotheAlgerianmigrationwaswillingtofacethatreality.Emigrationisneveran"exportofrawlaborpowerandnothingmore"(Sayad1999a,whichcannotbeexplainedtheonewithouttheother"(Sayad1999a

简介：torevealthatdiscoursesonimmigrationarealwaysperformativediscourseswhichhelpeffectthewondroussocialalchemywherebya"foreigner"ismadeintoa"national"(Sayad1987and1994).AllthisSayadknewordiscoveredbecausehewasmorethanascholarofimmigration,1981b)andhisvivisectionofexileasafallintosocialdarknessin"ElGhorba"(Sayad2000,asa"totalsocialfact"inMarcelMauss's(1990)senseoftheterm

简介：AlgerianImmigrationinFrance(GilletteandSayad1976),whichcannotbeexplainedtheonewithouttheother"(Sayad1999a,TowardsaSociologyofImmigration(SayadandFassa1982)

简介：Background:Soilorganiccarbon(SOC)isalargereservoirofterrestrialcarbon(C);itconsistsofdifferentfractionsofvaryingcomplexityandstability.PartitioningSOCintodifferentpoolsofdecomposabilityhelpbetterpredictthetrendofchangesinSOCdynamicsunderclimatechange.InformationonhowphysicalfractionsandchemicalstructuresofSOCarerelatedtoclimateandvegetationtypesisessentialforspatialmodelingofSOCprocessesandresponsestoglobalchangefactors.Method:Soilsampleswerecolectedfrommultiplerepresentativeforestsitesofthreecontrastingclimaticzones(i.e.cooltemperate,warmtemperate,andsubtropical)ineasternChina.MeasurementsweremadeonSOCcontentsandphysicalfractionsofthe0–20cmsoillayer,andthechemicalcompositionofSOCofthe0–5cmsoillayer,alongwithmeasurementsandcompilationofthebasicsiteandforeststandvariables.Thelong-termeffectsoftemperature,litterinputs,soilcharacteristicsandvegetationtypeontheSOCcontentsandfactionswereexaminedbymeansof"spacefortimesubstitution"approachandstatisticalanalysis.Result:Meanannualtemperature(MAT)variedfrom2.1℃atthecooltemperatesitesto20.8℃atthesubtropicalsites.TotalSOCofthe0–20cmsoillayerdecreasedwithincreasingMAT,rangingfrom89.2g·kg^-1incooltemperateforeststo57.7g·kg^-1insubtropicalforests,atanaveragerateof1.87%reductioninSOCwitha1℃increaseinMAT.WithincreasingMAT,theproportionsofaromaticCandphenolicCdisplayedatendencyofdecreases,whereastheproportionofalkylCandA/O-Avalue(theratioofalkylCtothesumofO-alkylCandacetalC)displayedatendencyofincreases.Overall,therewerenosignificantchangeswithMATandforesttypeineitherthephysicalfractionsorthechemicalcomposition.BasedontherelationshipbetweentheSOCcontentandMAT,weestimatethatSOCinthetop20soillayerofforestspotentiallycontribute6.58–26.3PgCgloballytotheat

简介：Thedistributionandchemicalpropertiesofcoloreddissolvedorganicmatter(CDOM)intheYellowSeaandtheEastChinaSeaduringDecember2011-January2012wereinvestigated.TheinputoffreshwaterandbiologicalactivitieshadanevidentinfluenceontheCDOMlevels(characterizedbythelightabsorptioncoefficientatthewavelengthof355nma355)inthestudyarea.ThespatialdistributionofCDOMlevelsdisplayedagraduallydecreasingtrendfromthecoastalwaters(0.37m^-1)totheopensea(0.18m^-1).Thespectralsloperatio(thesloperatioSRdefinedasS275-295:S350-400)duringthecruisewascorrelatedwithsalinity,andexhibitedalargevariationfrominshore(averageof2.515)tooffshoresites(averageof5.327)comparedwiththedistributionofa355.ThevaluesofSRwererelatedtoCDOMmolecularweight(MW).Thea355,SR,andchlorophyllain37samplescollectedfromthesurfacemicrolayerweresignificantlycorrelatedwiththoseinthecorrespondingsubsurfacewatersamples,implyingastrongexchangeactionbetweenthemicrolayerandbulkwater.Thea355andSRofCDOMexhibitedsignificantmicrolayerenrichment,withmeanenrichmentfactors(EFs)of1.72and1.62,respectively.

简介：TwonovelasymmetricorganicsmallmoleculesofIT(2FBT-T3Cz)2andIT(2FBT-TT3Cz)2withanindenothiophene(IT)centraldonorcore,fluorinatedbenzothiadiazole(2FBT)asacceptorand3-carbazole(Cz)unitasterminalgroupweredesignedandsynthesizedasthedonormaterialsinorganicsolarcells(OSCs).Thethermal,opticalabsorption,electrochemicalproperty,hole-electronmobility,filmmorphologywerethoroughlystudied.UsingPC71BMasanelectronacceptor,withoutanyadditiveandthermalannealing(TA)treatment,theIT(2FBT-T3Cz)2-basedcellsshowedapromisingpowerconversionefficiency(PCE)of5.81%andtheIT(2FBT-TT3Cz)2-basedcellsexhibitedaPCEof4.39%.OurresultsdemonstratethattheIT-basedasymmetricsmallmoleculescanbedevelopedasapromisingclassofdonormaterialsforhighperformanceOSCs.

简介：Herein,wereportthevictorioussynthesisofmetal-organicframeworks(MOFs)onTiO2nanotubes(NTs)usingalayer-by-layer(LbL)approach.HighlycrystallineandhomogenousthinfilmsofMOFsweregrownandcharacterizedusingXRD,SEM,FT-IRandUV/Visspectroscopy.Moreover,theutilizationoftheMOFfilmsassensitizerswasprobedinbespokeGraetzeltypeliquidjunctionsolarcells.TheconstructedcellperformancerevealedanIscof1.16mAcm–2,Vocof0.63V,FFof0.33,andEffof0.42%.Further,pumpprobetransientlaserspectroscopywasperformedtoinvestigatetheenergyandchargetransferdynamicsoftheMOFs/TiO2NTsinterface.Theresultsindicated86%injectionefficiency.Theultrafastpump-probespectroscopyallowstheinvestigationofthisprocessandthedifferencesbetweenMOFs.ItalsoshowedthattherelaxationoftheMOFchromophoresisincompetitionwithelectroninjectionintheTiO2motif.Thusthisstudyprovidesanewinsightintoelectrontransferfromphotoexcitedmetal-organicframeworks(MOFs)intotitaniumdioxide.

简介：Two-dimensional(2D)materialshavebeendemonstratedtoexhibituniquepropertiesoriginatingfromits2Dnature.Inrecentyears,theconstructionof2Dmaterialshasbecomeatopicofgreatinterest.Thisarticlesummarizestherecentadvanceof2Dsupramolecularorganicframeworks(SOFs)whicharehomogeneouslyconstructedinsolutionphasethroughself-assemblyofrationallydesignedbuildingblocks.These2DSOFsaresolubleandstillmaintainstablenetworkstructuresinsolutions,whichexhibituniquenessnotonlyinstructuresbutalsoinproperties.Inthisconcisereview,theSOFs-relatedbackgroundisbrieflyintroducedfirstly,followedbyoutliningtheresearchprogressofsoluble2DSOFsfromtheperspectiveofmonomerdesign,assembly,andstructuralcharacterization.Thearticleendswithapersonaloutlookonthefuturedevelopmentofthisnewclassofsupramolecularpolymers.

简介：Nutrient-poor,sandysoilsformtheprevailingsubstrateatpost-miningsitesoftheLusatianregion(Brandenburg,Germany)andpresentachallengeforvegetationdevelopment.Westudiedtheorganicacidquantityandcompositionofthreecommonlyoccurringpioneerplantspecies,thelegumesLotuscorniculatusL.andTrifoliumarvenseL.andthegrassCalamagrostisepigeios(L.)Roth,todetermineifplantgrowthandexudationdifferedwith(non-sterilizedsoil)andwithout(sterilizedsoil)anindigenoussoilmicrobialcommunity.Weinvestigatedwhetherorganicacidswerefoundintherhizosphereandsurroundingsoilandwhetherthisinfluencednutrientmobilization.Thisstudyconsistsoflinkedfieldinvestigationsandagreenhouseexperiment.Plantsweregrowninthegreenhouseineithersterilizedornon-sterilizedsandysoilfromareclamationsiteintheLusatianmininglandscape(WelzowSu¨d,EastGermany).Aftersevenmonths,theplantbiomass,rootmorphology,organicacids,andwater-solublenutrientsandrootcolonizationwitharbuscularmycorrhizalfungi(AMF)anddarkseptateendophytes(DSE)wereanalyzed.RootsofallthreeplantsinthefieldandgreenhouseexperimentswerehighlycolonizedwithAMF.CalamagrostisepigeiosandT.arvensehadasignificantlyhighercolonizationfrequencywithDSEthanL.corniculatus.Thequantityandcompositionoforganicacidsstronglydifferedamongplantspecies,withthehighestnumberoforganicacidsfoundforL.corniculatusandlowestforC.epigeios.Thequantityoforganicacidswasgreatlyreducedinallplantsundersterilizedsoilconditions.However,thecompositionoforganicacidsandplantgrowthinsterilizedsoilwerereducedforbothlegumes,butnotforC.epigeios,whichhadahigherbiomassundersterilizedconditions.Changesinnutrientconcentrationsinthefieldrhizospheresoilrelativetothoseinthecontrolweremeasurableaftersevenmonths.Whilethespectrumoforganicacidsandthegrowthoflegumesseemedtobedependentonahighly