Lub hauv paus ntsiab lus ua haujlwm ntawm kis tau tus mob electron microscope
Transmission electron microscope (Transmission Electron Microscope, TEM luv luv) tuaj yeem pom cov microstructures me dua {{0}}}.2um uas tsis tuaj yeem pom meej hauv qab lub tshuab ntsuas qhov muag. Cov qauv no hu ua submicrostructures lossis ultrastructures. Txhawm rau pom cov qauv no kom meej, lub teeb pom kev zoo nrog lub wavelength luv dua yuav tsum tau xaiv los ua kom qhov kev daws teeb meem ntawm lub tshuab tsom. Xyoo 1932, Ruska tau tsim lub tshuab hluav taws xob xa hluav taws xob nrog lub teeb hluav taws xob ua lub teeb ci. Lub wavelength ntawm lub electron beam yog luv luv tshaj li qhov pom lub teeb thiab ultraviolet lub teeb, thiab lub wavelength ntawm lub electron beam yog inversely proportional rau lub square root ntawm lub voltage ntawm lub emitted electron beam, uas yog, qhov siab dua qhov voltage. qhov luv luv wavelength. Tam sim no, qhov kev daws teeb meem ntawm TEM tuaj yeem ncav cuag 0.2 nm.
Lub hauv paus ntsiab lus ntawm kev ua haujlwm ntawm lub tshuab hluav taws xob xa hluav taws xob yog tias cov hluav taws xob hluav taws xob tawm los ntawm cov phom hluav taws xob hla dhau los ntawm cov condenser raws li qhov pom ntawm daim iav lub cev hauv lub tshuab nqus tsev, thiab yog condensed rau hauv ib qho chaw ntse, ci thiab teeb pom kev zoo los ntawm lub condenser. , thiab illuminates tus qauv hauv cov qauv chamber. Nyob rau; cov kab hluav taws xob tom qab dhau los ntawm cov qauv nqa cov ntaub ntawv hauv cov qauv, cov khoom siv hluav taws xob dhau los ntawm qhov ntom ntom ntawm cov qauv me me, thiab cov khoom siv hluav taws xob dhau los ntawm qhov sib txawv yog ntau dua; Tom qab kev tsom xam thiab thawj qhov kev nthuav dav ntawm lub hom phiaj lens, lub teeb hluav taws xob Lub teeb nruab nrab ntawm lub lens nkag mus rau theem qis thiab thawj thiab thib ob tsom iav tsom iav ua kom pom kev nthuav dav, thiab thaum kawg cov duab hluav taws xob loj yog npaj rau ntawm lub vijtsam fluorescent hauv chav soj ntsuam. ; fluorescent screen hloov cov duab hluav taws xob rau hauv cov duab pom lub teeb rau cov neeg siv saib. Tshooj lus no yuav qhia txog cov qauv tseem ceeb thiab cov hauv paus ntsiab lus ntawm txhua qhov system feem.
Transmission Electron Microscope Imaging Principles
Lub hauv paus ntsiab lus imaging ntawm kis tau tus mob electron microscope tuaj yeem muab faib ua peb qhov xwm txheej:
1. Daim duab nqus: thaum hluav taws xob ntaus tus qauv nrog siab loj thiab ceev, cov theem tseem-sib sau ua tiav yog tawg. Qhov twg qhov loj thiab tuab ntawm cov qauv loj dua, qhov tawg ntawm lub kaum sab xis ntawm cov hluav taws xob loj dua, thiab cov hluav taws xob tsawg dhau mus, thiab qhov ci ntawm daim duab yog tsaus dua. Thaum ntxov kis tau tus mob electron microscopes raws li txoj cai no.
2. Cov duab diffraction: Tom qab cov kab hluav taws xob sib txawv ntawm cov qauv, qhov diffraction yoj amplitude faib ntawm qhov sib txawv ntawm cov qauv sib raug rau qhov sib txawv diffraction zog ntawm txhua feem ntawm cov siv lead ua hauv cov qauv. Lub amplitude kev faib tawm ntawm cov nthwv dej sib txawv tsis sib xws, cuam tshuam txog kev faib cov khoom siv lead ua tsis xws luag.
3. Phase duab: Thaum tus qauv yog thinner dua 100Å, electrons tuaj yeem dhau los ntawm cov qauv, thiab qhov hloov pauv yoj amplitude tuaj yeem tsis quav ntsej, thiab cov duab los ntawm cov theem hloov.
Kev siv kis hluav taws xob hluav taws xob Microscopy
Transmission electron microscopy yog siv dav hauv cov ntaub ntawv science thiab biology. Txij li thaum electrons tau yooj yim tawg los yog nqus los ntawm cov khoom, qhov nkag mus yog qhov tsawg, thiab qhov ntom thiab tuab ntawm cov qauv yuav cuam tshuam rau qhov kawg imaging zoo. Thinner ultrathin seem yuav tsum tau npaj, feem ntau yog 50-100 nm. Yog li ntawd, cov qauv rau kev soj ntsuam los ntawm kev sib kis electron microscope yuav tsum tau ua tiav heev thinly. Cov kev siv feem ntau yog: ultra-thin sectioning, khov ultra-thin sectioning, khov-etching, khov-pob txha thiab lwm yam. Rau cov qauv ua kua, nws yog feem ntau pom los ntawm dai rau ntawm daim phiaj tooj liab pretreated.
