简介:Extractingrare-earthelementsfromcoalcouldsoonbeeconomicalinU.S.ExtractedfromthereportofUNIVERSITYPARK,Pa.TheU.S.couldsoondecreaseitsdependenceonimportingvaluablerare-earthelements,accordingtoateamofPennStateandU.S.DepartmentofEnergyresearcherswhofoundacost-effectiveandenvironmentallyfriendlywaytoextractthesemetalsfromcoalbyproducts.UsingbyproductsofcoalproductionfromtheNorthernAppalachianregionoftheU.S.,theteaminvestigatedwhetherachemicalprocesscalledionexchangecouldextractREEsinasafermannerthanotherextractionmethods.Resultsshowthationexchangeismoreenvironmentallyfriendlyandrequiresless
简介:Terahertzwaves,sittinginthegapbetweenthemiddleinfraredandmillimeterwaveregions,areknownasthelasvacantareaoftheelectromagneticspectrumthathasnotquitebeenunderstoodandbroughtintoapplications.TheTerahertzregionhasbeenthefocusofresearchworldwidesinceearly1990s.DuetotheiruniquecharacteristicsTerahertztechnologieshaveawiderangeofapplications,suchashazarddetection,highspeeddatacommunications
简介:Terahertzwaves,sittinginthegapbetweenthemiddleinfraredandmillimeterwaveregions,areknownasthelastvacantareaoftheelectromagneticspectrumthathasnotquitebeenunderstoodandbroughtintoapplications.TheTerahertzregionhasbeenthefocusofresearchworldwidesinceearly1990s.Duetotheiruniquecharacteristics,
简介:Brainisthemostcomplexorganofhumanbeings.Thecompleteunderstandingofhumanbrains’functionsisanongoingchallengeforneuroscience.Althoughtherearemanytechniquesusedforbrainresearch,neuroscientists,physicists,andengineersarestillexploringotheraccessofresearchforapplications.Terahertz(THz)spectroscopyandimagingmaycreatesuchaspaceforbrainresearch.THzspectroscopictechnique,whichisanovelmedicalimagingmodality,attractsattentionofbiomedicalapplicationsduetoitsuniquefeaturesincludingnon-invasive,non-ionizing,andhighsensitivitytobiomoleculesandtissues.Inthisarticle,weintroduceourrecentinvestigationsonneuroscienceusingTHztechniques,meanwhile,introduceother’sworkinthisfield.Ourandothers’investigationsindicatethattheTHzspectroscopyandimagingtechniquecanbeusefulfordiagnosingbraintumorsandneurodegenerativediseases.THzspectroscopyandimaginghasthepotentialtobecomereal-timeinvivodiagnosticmethods.
简介:Thispaperoptimizestheburiedchannelcharge-coupleddevice(BCCD)structurefabricatedbycomplementarymetaloxidesemiconductor(CMOS)technology.TheoptimizedBCCDhasadvantagesoflownoise,highintegrationandhighimagequality.Thechargetransferprocessshowsthatinterfacetraps,weakfringingfieldsandpotentialwellbetweenadjacentgatesallcausethedecreaseofchargetransferefficiency(CTE).CTEandwellcapacityaresimulatedwithdifferentoperatingvoltagesandgapsizes.CTEcanachieve99.999%andthewellcapacityreachesupto25000electronsforthegapsizeof130nmandthemaximumoperatingvoltageof3V.
简介:Weproposeadepolarizerbasedontheprincipleofacollectionofhalf-waveplateswithrandomlydistributedopticaxes.Thedesignisdemonstratedbymeansofdynamicallyphotopatterningliquidcrystalintorandomlyalignedhomogeneousdomains.Wecharacterizetheliquidcrystaldepolarizerfor1550nmandC-band(1520–1610nm).Adegreeofpolarizationoflessthan5%isobtainedforanylinearlypolarizedlight.Thisstudyprovidesapracticalcandidateforhigh-performancedepolarizers.
简介:JEST—JournalofElectronicScienceandTechnology,formerly,JournalofElectronicScienceandTechnologyofChina,ispublishedquarterlydevotingtothestate-of-the-artachievementsinelectronicscienceandtechnology,includingthemosthighlightareas:communicationtechnology,electronicsystemsandarrayprocessing,computerscienceandinformationtechnology,optoelectronicand
简介:Inthelastdecadestheinterestinthebiomassgasificationprocesshasincreasedduetothegrowingattentiontotheuseofsustainableenergy.Biomassisarenewableenergysourceandrepresentsavalidalternativetofossilfuels.Gasificationisthethermochemicalconversionofanorganicmaterialintoavaluablegaseousproduct,calledsyngas,andasolidproduct,calledchar.Thebiomassgasificationrepresentsanefficientprocessfortheproductionofpowerandheatandtheproductionofhydrogenandsecond-generationbiofuels.Thispaperdealswiththestateoftheartbiomassgasificationtechnologies,evaluatingadvantagesanddisadvantages,thepotentialuseofthesyngasandtheapplicationofthebiomassgasification.Syngascleaningthoughfundamentaltoevaluateanygasificationtechnologyisnotincludedinthispapersince;intheauthors'opinion,adedicatedreviewisnecessary.
简介:Nuclearfusionhasenormouspotentialtogreatlyaffectglobalenergyproduction.Thenext-generationtokamakITER,whichisaimedatdemonstratingthefeasibilityofenergyproductionfromfusiononacommercialscale,isunderconstruction.Wallerosion,materialtransport,andfuelretentionareknownfactorsthatshortenthelifetimeofITERduringtokamakoperationandgiverisetosafetyissues.Thesefactors,whichmustbeunderstoodandsolvedearlyintheprocessoffusionreactordesignanddevelopment,areamongthemostimportantconcernsforthecommunityofplasma-wallinteractionresearchers.Todate,lasertechniquesareamongthemostpromisingmethodsthatcansolvetheseopenITERissues,andlaser-inducedbreakdownspectroscopy(LIBS)isanidealcandidateforonlinemonitoringofthewallsofcurrentandnext-generation(suchasITER)fusiondevices.LIBSisawidelyusedtechniqueforvariousapplications.Ithasbeenconsideredrecentlyasapromisingtoolforanalyzingplasma-facingcomponentsinfusiondevicesinsitu.ThisarticlereviewstheexperimentsthathavebeenperformedbymanyresearchgroupstoassessthefeasibilityofLIBSforthispurpose.
简介:Withthedeepeningofthewesterndevelopment,supportsofthecountryforthewesternregionofChinacontinuedtoincrease.Italsoincludesthesupportforenterpriseinnovationactivities,byreducingthetax,exemption,subsidiesandothermeans.Duetotheeffectofgovernmentsubsidiesonenterpriseinnovationactivitiesisdifferentindifferentregions,industriesandsoon,thereisabigcontroversy.Therefore,weusethepaneldataoflistedcompaniesinmanufacturingindustryofwesternregionassamplesforempiricalresearch,toresearchtheeffectofgovernmentsubsidiesonenterpriseinnovationactivitiesinthewesternofChina,thestudyfoundthatoverall,thecurrentgovernmentsubsidieshasapositiveeffectonEnterpriseR&Dinvestment,whereasthelastyear’sgovernmentsubsidyhasanegativeeffectonR&Dinvestment,butit’sincentiveeffectisgreaterthanthecrowdingouteffect.Thestudyalsofoundtherearedifferenteffectsbetweenthestate-ownedenterprisesandprivateenterprises,thecrowdingouteffectofprivateenterprisesisverysmallandnotsignificant.
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简介:Wepresentintegrated-opticbuildingblocksandfunctionalphotonicdevicesbasedonamorphoussiliconon-insulatortechnology.Efficientdeep-etchedfiber-to-chipgratingcouplers,low-losssingle-modephotonicwirewaveguides,andcompactpowersplittersarepresented.Basedonthesub-μmphotonicwires,2×2Mach–Zehnderinterferometersandadd/dropmicroringresonators(MRRs)withlowdevicefootprintsandhighfinesseupto200wererealizedandstudied.Compactpolarizationrotatorsandsplitterswith≥10dBpolarizationextinctionratiowerefabricatedforthepolarizationmanagementon-chip.Thetuningandtrimmingcapabilitiesofthematerialplatformaredemonstratedwithefficientmicroheatersandapermanentdevicetrimmingmethod,whichenabledtherealizationofenergy-efficientphotoniccircuits.Wavelengthmultiplexersintheformofcascadedfilterbanksand4×4routersbasedonMRRswitchesarepresented.Fabricationimperfectionswereanalyzedandpermanentlycorrectedbyanaccuratelaser-trimmingmethod,thusenablingeight-channelmultiplexerswithrecordlowmetricsofsub-mWstaticpowerconsumptionand≤1°Ctemperatureoverhead.Thehighqualityofthefunctionaldevices,thehightuningefficiency,andtheexcellenttrimmingcapabilitiesdemonstratethepotentialtorealizelow-cost,denselyintegrated,andultralow-power3D-stackedphotoniccircuitsontopofCMOSmicroelectronics.
简介:Inthispaper,weproposeamethodtoimproveanti-radiationcapabilitybycoatingheavymetalX-rayprotectionglasswithcompoundphotoniccrystallayers,basedontheuniquepropertyofphotoniccrystalthatlightcannotbepropagatedwithintherangeofbandgaps.Usingtheplanewaveexpansionmethod,wemadeatheoreticalstudyofparametersaffectingthebandgapstructuresofone-dimensionalphotoniccrystals.Basedonthefindings,wechoseappropriatematerialsandcompoundstructureofphotoniccrystalsoastogethighX-rayreflectioncoatingphotoniccrystallayers.Bythismethod,thereflectionratewithinX-raywavelengthcanreachthemaximumvalueof100%,andtheaveragevalueofover90%.Evenlow-costheavymetalX-rayprotectionglassofabsorptioncoefficientvaluecanachievethedesiredeffect.Thus,thismethodgreatlydecreasestheanti-radiationrequirementsofheavyX-rayprotectionglass.