Dab tsi yog qhov txawv ntawm lub teeb microscopy thiab electron microscopy?
Ib qho kev siv tshuaj kho qhov muag pom kev siv lub teeb pom kev los teeb cov qauv thiab cov iav lo ntsiab muag los nthuav cov duab ntawm cov qauv. Txij li thaum koj siv lub teeb, koj tuaj yeem tso cov qauv hauv qab lub tshuab ntsuas cua hauv huab cua, lossis rau qee qhov kev siv, hauv dej lossis roj me me. Rau cov teeb pom kev zoo sib txuas, peb feem ntau xav tau cov qauv kom nyias nyias vim peb xav kom lub teeb hla nws kom peb pom cov ntsiab lus sab hauv. Qhov no feem ntau txhais tau hais tias txiav ntu ntawm cov qauv, tab sis nyob ntawm tus qauv, qhov tuab ntawm cov seem yuav yog li 1 txog 20 microns. Nrog lub tso suab los yog dissecting lub teeb microscopy, tsis muaj qhov yuav tsum tau vim tias koj tsuas yog saib ntawm qhov chaw ntawm tus qauv. Saib xyuas cov duab loj nyob rau hauv ib lub tshuab kho qhov muag los ntawm lub qhov muag,
Electron microscopes siv lub teeb pom kev zoo ntawm cov khoom siv hluav taws xob ua lub teeb pom kev zoo. Lub beam yog tswj thiab tsom los ntawm ib tug series ntawm electromagnetic lo ntsiab muag, uas yog tseem ceeb heev haib electromagnetic coils nrog ib tug central qhov uas cov electrons hla. Lub lens tswj lub teeb beam tsoo tus qauv thiab tseem ua kom pom cov duab ntawm tus qauv. Txij li thaum koj ua hauj lwm nrog ib tug electron beam, tag nrho cov electron optical system yuav tsum tau nyob rau hauv lub siab nqus tsev vacuum, uas txhais tau hais tias tus qauv yuav tsum haum rau lub nqus tsev vacuum. Hauv kev xa xov hluav taws xob tshuab hluav taws xob (TEM), cov khoom siv hluav taws xob yuav tsum dhau los ntawm cov qauv, yog li cov qauv yuav tsum nyias nyias, tsawg dua 0.1 microns. Cov duab loj tau pom ntawm lub vijtsam fluorescent tab sis tuaj yeem kaw nrog lub koob yees duab CCD mounted hauv qab lossis saum lub vijtsam.
Scanning electron microscopy (SEM) zoo ib yam li lub tshuab kuaj kab mob kho qhov muag hauv ib txoj hauv kev, nyob rau hauv uas koj tab tom saib zoo heev ntawm qhov chaw ntawm tus qauv, yog li nws tsis tas yuav nyias. Hauv SEM, cov qauv raug tshuaj xyuas nrog lub teeb pom kev zoo electron beam, yog li cov qauv yuav tsum muaj peev xwm tiv taus lub tshuab nqus tsev siab thiab yuav tsum muaj qhov ua tau zoo. (Qhov no yog vim tias koj tab tom tso cov kwj ntawm electrons mus rau hauv cov qauv, thiab tam sim no yuav tsum tau ua tam sim no.) SEM cov qauv feem ntau coated nrog cov txheej nyias nyias ntawm cov pa roj carbon lossis hlau (xws li kub lossis chromium) ua rau lawv ua tau.
Cov lus saum toj no piav qhia qhov sib txawv ntawm kev ntsuas lub cev, thiab kuv tsis tau hais tias lub tshuab ntsuas hluav taws xob yog qhov loj dua thiab nyuaj dua li lub teeb microscopes. Tab sis qhov sib txawv tseem ceeb ntawm lub teeb thiab electron microscopy yog kev daws teeb meem - lub peev xwm los daws cov ntsiab lus me me. Kev daws teeb meem yog qhov kawg txwv los ntawm lub wavelength ntawm lub teeb nyob rau hauv optical microscopy thiab qhov zoo wavelength ntawm electron beam hauv electron microscopy. Txij li thaum lub wavelength ntawm pom lub teeb yog kwv yees li ntawm {{0}}} nanometers, qhov pom kev daws teeb meem ntawm optical microscopy yog kwv yees li 200 nanometers (0. 2 micrometers). Rau TEM kev khiav hauj lwm ntawm 200 kilovolts, lub wavelength ntawm lub electron beam yog 0.0025 nanometers, qhov tseeb daws teeb meem ntawm xws li ib tug ntsuas yog hais txog 0.2 nanometers, los yog ib txhiab lub sij hawm zoo dua ib tug optical microscope. Advanced TEMs yuav muaj kev daws teeb meem ze li 0.1 nanometers, thiab Ntau TEMs tuaj yeem ua duab atoms hauv cov qauv tsis tu ncua.
Txij li thaum magnification tsuas yog qhov piv ntawm yuav ua li cas ib qho khoom tshwm rau lub qhov muag lossis lub vijtsam piv rau nws qhov loj me, qhov no txhais tau hais tias lub tshuab ntsuas qhov muag zoo heev muaj qhov loj tshaj plaws ntawm 1000-2000x thiab qhov siab tshaj plaws muaj magnification ntawm qhov zoo. TEM yog 1-2 lab zaug. Rau SEM, muaj ntau yam tseem ceeb uas cuam tshuam rau kev daws teeb meem, thiab qhov siab tshaj plaws muaj qhov nthuav dav yog nyob ib puag ncig 300,000x.
Raws li koj tuaj yeem pom, muaj ntau qhov sib txawv ntawm lub teeb thiab electron microscopy, nrog rau cov teeb meem daws teeb meem yog qhov tseem ceeb. Rau cov kev siv tswv yim, kev xaiv ntawm cov cuab yeej siv twg yuav yog qhov kawg nyob ntawm qhov kev daws teeb meem thiab kev nthuav dav uas xav tau thiab qhov yooj yim ntawm cov qauv npaj.
