简介:the most important technique a teacher can use to guide students toward grammatically correct writing is to let them write,teachers are encouraged to adopt a more moderate approach to error. If the teacher over-corrects the students’ mistakes,it is more helpful to select one or two kinds of errors the individual student is making than to point out every error in the paper. The teacher can identify a selected error
简介:Consideringthatinamagneticresonancesystem,ifthedetectioncoilcontributesdominantlytothesystemnoise,theperformanceofthewholesystemcancertainlybeimprovedbyswitchingtoadetectioncoilmadeofahigh-temperaturesuperconductor,andusingYBa2Cu3O7thinfilmson25×25mm^2LaAlO3substrates,wehavepreparedtwokindsofdetectioncoils:single-coilandtwo-coil.encouragingly,theirqualityfactorsaremeasuredtobeQ>2500fortwo-coil(at22.566MHzand77K)andQ>5500forsingle-coil(at92.3MHzand77K),respectively,Here,wedescribethedetailsofthedesign,fabricationandtestingofthecoils.
简介:Newacetylenemonomers,6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-l-phenyl-l-hexyne(1),2,5-diethynylthiophene(3),and4,4′-diethynylbiphenyl(6)weresynthesized.Homopolymerizationof1andcopolycyclotrimerizationsof3and6with1-heptyneandl-octynehavebeenachievedwithWCI6-andTaC15-Ph4Sncatalysts,respectively,givingsolublelineardisubstitutedpolyacetylene(2)andhyperbranchedpolyarylenes(5and8)withhighmolecularweights(upto1.2×105)inhighyields(upto98%).ThestructuresandpropertiesofthepolymersarecharacterizedandevaluatedbyIR,NMR,TGA,UV,photoluminescence(PL),andelectroluminescence(EL)analyses.Allthepolymerspossesshighthermalstabilityandemitstrongbluelightuponphotoexcitation.Theintensityoftheemittedlightisgreaterthanthatofpoly(1-phenyl-1-octyne),awell-knownhighlyluminescentdisubstitutedpolyacetylene.Littleaggregation-inducedredshiftinthePLwasobservedinthethinfilmsofthepolymers.Byconstructingamulti-layerELdevice,highELquantumyield(0.18%)hasbeenachievedin2,whicharethebestresultsforsubstitutedpolyacetylenesattainablesofar.
简介:Inthispaper,wereviewthestatusofthemultifunctionalexperimentalplatformattheNationalLaboratoryofHighPowerLaserandPhysics(NLHPLP).Theplatform,includingtheSG-IIlaserfacility,SG-II9thbeam,SG-IIupgrade(SG-IIUP)facility,andSG-II5PWfacility,isoperationalandavailableforinterestedscientistsstudyinginertialconfinementfusion(ICF)andabroadrangeofhigh-energy-densityphysics.Thesefacilitiescanprovideimportantexperimentalcapabilitiesbycombiningdifferentpulsewidthsofnanosecond,picosecond,andfemtosecondscales.Inaddition,theSG-IIUPfacility,consistingofasinglepetawattsystemandaneight-beamnanosecondsystem,isintroducedincludingseverallasertechnologiesthathavebeendevelopedtoensuretheperformanceofthefacility.RecentdevelopmentsoftheSG-II5PWfacilityarealsopresented.
简介:Itisexpectedthatinthenewcentury,tocopewithdevelopmentsofnewhightemperaturetechnologies,anewgenerationofhighperformancerefractoryceramicswillemergeandflourishwhichshouldincludethefollowing(1)oxideandnonoxidecompositescharacterizedbyauniquecombinationofhighhotstrength,highthermalshockresistanceandhighcorrosionresistance;(2)freeCaObearingbasicrefractoriescapableofpurifyingmoltenmetalforimprovingcleanlinessandofabsorbingcontaminantsfromwastegasesforreducingenvironmentalpollution;(3)freeflowingzerocementcastableswithimprovedthermomechanicalproperties,thermalshockresistanceandcorrosionresistanceandgradientcastableswithvaryingmatrixcompositionandvaryingtexture.
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简介:in the teaching of reading teachers often do just that. Rather than let the students into,teachers can offer their students texts,When the teachers give reading class to students
简介:Withtherapiddevelopmentofdeepsubmicron(DSM)VLSIcircuitdesigns,manyissuessuchastimeclosureandpowerconsumptionaremakingthephysicaldesignsmoreandmorechallenging.InthisreviewpaperweprovidereaderswithsomerecentprogressoftheVLSIphysicaldesigns.Therecentdevelopmentsoffloorplanningandplacement,interconnecteffects,modelinganddelay,bufferinsertionandwiresizing,circuitorderreduction,powergridanalysis,parasiticextraction,andclocksignaldistributionarebrieflyreviewed.
简介:Wepresentapseudo-inverseghostimaging(PGI)techniquewhichcandramaticallyenhancethespatialtransverseresolutionofpseudo-thermalghostimaging(GI).IncomparisonwithconventionalGI,PGIcanbreakthelimitationontheimagingresolutionimposedbythespeckle’stransversesizeontheobjectplaneandalsoenablesthereconstructionofanN-pixelimagefrommuchlessthanNmeasurements.Thisfeaturealsoallowshigh-resolutionimagingofgray-scaleobjects.Experimentalandnumericaldataassessingtheperformanceofthetechniquearepresented.
简介:Neutralbeaminjectionisoneofthemainplasmaheatingmethodsinnuclearfusiondevices.InordertosupportthescientificstudyoftheExperimentalAdvancedSuperconductingTokamak(EAST),amegawatt-levelhighcurrentionsourceisdesignedandmanufacturedintheASIPP,andtheprogressandpreliminarytestresultswillbepresentedinthispaper.
简介:Thispaperintroducestwokindsofmethodswithhighaccuracyforfi-niteelementprobabilitycomputingmethod,bywhichthefunctionvalueononeorafewnodescanbecalculatedwithoutformingthetotalstiffnessmatrix.
简介:B_2O_3-P_2O_5-SiO_2(BPS)three-dimensional(3D)high-organizedpolystyrene(PS)opalsandinverseopalswithlargedomainwerefabricatedandcharacterized.Scanningelectronmicroscope(SEM)showsthreeorfoursmall'windows',indicatingthataverywellinterconnectionbetweenPSspheresofopal.Theultraviolet-visible(UV-vis)spectraindicatethatthephotonicbandgaps(PBGs)areabout710and604nmfor320-and270-nmspheresrespectively.WhileaccordingtoBragg'sequation,thesimulationresultsshouldbe762and643nm,whichmeanthat52and39nmwereshiftedtoblueregion,respectively.