简介：英文中的动词(verb),经常以片语(phrase)形式出现,即在原本的动词后面加上一个或多个介词(preposition),形成“片语形式的动词”或“动词片语”(phrasalverb)。这种表达方式是英文的特性,数目繁多,学习者必须搞通这些片语的特别含义,以免囫囵吞枣,混淆不清,而错误百出。

简介：TheMinistryofAerospaceIn-dustrychairedameetingonNove-mber6-8,1991inBeijingtore-viewrareearthapplicationsinaircraft.Over70delegatesfrom37domesticinstitutionsattended

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简介：Inthispaper,arecursivequadraticprogrammingalgorithmisproposedandstudied.ThelinesearchfunctionsusedaxeHan'snondifferentiablepenaltyfunctionswithasecondoederpenaltyterm.InordertoavoidmaratoseffectFukushima'smixeddirectionisusedasthedirectionoflinesearch.Finally,weprovetheglobalconvergenceandthelocalsecondorderconvergenceofthealgorithm.

简介：Itisofpracticalsignificanceforthedecision-makingoncountryfoodsecurityandfarmlandprotectiontoanalyzetheconversionmarginsforthemajorusesofagriculturallandandtheirvariations.Basedonthepaneldataofwheat,corn,vegetable,fruit,andforestsproductionsfrom520investigatedfarmerhouseholdsof13investigatedvillagesinShandongProvincefrom2003to2009,andusingCobb-Douglasproductionfunction,therevenueconversionmarginscanbeobtainedseparately,betweendifferentgrain-crops(wheat,corn)anddifferentnon-graincrops(vegetable,fruit,forests),andtheconversionrelationshipbetweengrowinggrain(wheat,corn)andgoingoutfornon-farmwork.Theresultsshowthatfrom2003to2009,growingwheatandcornaremoreeconomicallyandreasonablyforfarmers,comparedwithgrowingvegetable,butgrowingwheatandcornarebecominglesseconomicallyandlessreasonablydaybyday,comparedwithplantingforests.Moreover,theconversionmarginbetweenwheatandfruitshowsobviousscissorsdifference.Justfrom2007,farmers'growingfruitbecameeconomicallyandreasonably,butuntil2009,comparedwithgoingouttoworkafterabandoningfarm8land,growingwheathadnoeconomicrationality.From2003to2009,farmers'growingcornismoreprofitablethangrowingfruitandgoingoutfornon-farmworkafterabandoningfarmland.Thesubsidiesforwheatandcornhaveincreasedfarmers'comparativeincomefromfoodproductionremarkably,butthesubsidiescannotchangethegeneraltendencythatfarmerstransformfood(wheat,corn)productionintonon-food(especiallyforests)production.Therevenuedifferencebetweengrowingwheat,cornandvegetableandgrowingfruitandforestsisbeingpulledceaselesslybigger,andthetendencythatfarmerstransformwheat,cornandvegetablegrowinglandsintofruitandforestsgrowinglandshasbecomeincreasinglyapparent.

简介：Amajorenergyconservationandretrofittingproject—ap-plicationofnaturalgasassupplementaryfuelforsteamcrackershasbeensuccessfullyputintooperationstartingApril30,2008attheSINOPECYangziPetrochemicalCompany.Foralongtimethesteamcrackersintheoldandnewplant-sitesattheYangziPetrochemicalCo.usedtoconsumemeth-

简介：MatthiasLtitolfandhisPhDstudent,twoscientistsattheEPFL＇sInstituteofBioengineering,havedevelopedanewtechniqueforusinglaserstocarvepathwaysinhydrogelscaffoldsina3Dcellcultureenvironmenttocontrolthegrowthoftheculture.

简介：Thepealeafminer(Liriomyzahuidobrensis)isanotoriouspestofvegetablesandornamentalplantsworldwide.Despitealargenumberofstudiesonitsbiologyandecology,thecourtshipbehaviorandsexualcommunicationofthisspeciesremainunclear.Here,westudiedvibrationalcommunicationinthesexualinteractionofthepealeafminer.Onhostplantleaves,femalesandmalesbehaviorallydisplayedthebobbing-quiveringalternation,whichfinallyledtocopulation.Moreover,recordsoflaservibrometryrevealedthreesignalduetsunderlyingthebehavioralalternation.Sexuallymaturemalesspontaneouslyemittedcalls(MCs)toinitiatetheduets.ThefemalesrapidlyrespondedtoMCsbyemittingreplies(FRs)thatarelongerinduration.TheFRsfurthertriggeredmalereplies(MRs)intheirsearchforpotentialpartners.Leafminer-producedvibrationalsignalsconveyefficientinformationtopartnersandgeneratepairformationonstretchedsubstrates,suchasplantleavesandnylonmesh,butcannotelicitresponsesondensesubstrates,suchasglassandplastic.VibrationalplaybacksofbothMCsandFRscanelicitrepliesinfemalesandmales,respectively.Thisstudycompletelycharacterizessubstrate-bornevibrationalduetsinadipteraninsect.Thediscoveryofvibrationalsexsignalsinthepealeafminerprovidesnewinsightsforthedevelopmentofnovelapproachestocontrolthepestanditsrelativespecies.

简介：Soilnitrogenpools(NP),denitrification(DN),grossnitrification(GN),N2OandCO2fluxrateswiththeirresponsestotemperatureincreasesweredeterminedunderfivedifferentlandusesandmanagementsinasubalpineforest-grasslandecotoneoftheeasternTibetanPlateau.Landusesconsistedof1)sparsewoodland,2)shrub-land,3)naturalpasture,4)fencedpasture,and5)tilledpasturemimickingagradientdegeneratingecosystemundergrazingimpacts.TheNO3--NcontentwashigherthantheNH4+-Ncontent.Comparingtilledpasturewithfencedpastureshowedthathigherintensivemanagement(tillage)ledtoasignificantdecreaseofsoilorganicmatter(SOM)(P＜0.05)inthesoils,whichwasincontrasttothesignificantincreases(P＜0.05)ofDN,GN,N2OandCO2fluxrates.GN(excludingtilledpasture)andCO2fluxratesincreasedwithatemperaturerise,butDNandN2Ofluxratesnormallyreachedtheirmaximumvaluesat12-14℃withtilledpasture(thehighestmanagementintensity)beingverysensitivetotemperatureincreases.TherewasadifferencebetweennetnitrificationandGN,withGNbeingabetterindicatorofsoilnitrification.

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简介：ThiscriticalreviewassessesEliHinkel’sresearchpaperTheEffectsofEssayTopicsonModalVerbUsesinL1andL2AcademicWritingintermsofbothwritingprocessandwritingproduct.Itacknowledgesthemeritsaswellastheflawsofthepaperandconcludeswithfuturestudysuggestions.