Pib nrog Transmission Electron Microscopy
Transmission Electron Microscope (TEM luv luv), tuaj yeem pom hauv lub tshuab ntsuas qhov muag pom tsis tau pom meej hauv tsawg dua 0.2 um microstructure, cov qauv no hu ua sub-microscopic qauv lossis ultramicrostructure. Txhawm rau pom cov qauv no kom meej, nws yog qhov yuav tsum tau xaiv lub teeb lub teeb luv luv los txhim kho qhov kev daws teeb meem ntawm lub tshuab tsom.
Taw qhia
Lub hauv paus ntsiab lus ntawm kev kos duab ntawm electron microscope thiab optical microscope yog qhov zoo ib yam, qhov txawv yog qhov qub siv lub teeb hluav taws xob ua lub teeb ci thiab electromagnetic teb raws li lub lens. Tsis tas li ntawd, vim qhov tsis muaj zog nkag ntawm cov nqaj hlau hluav taws xob, yog li cov qauv siv rau electron microscopy yuav tsum tau ua rau hauv ib qho ultra-thin seem nrog lub thickness ntawm txog 50nm. Xws li cov hlais yuav tsum tau ua nrog ib qho ultramicrotome. Electron microscope magnification mus txog ze li ntawm ib lab lub sij hawm, los ntawm lub teeb pom kev zoo, kev teeb pom kev zoo, lub tshuab nqus tsev, lub kaw lus kaw lus, lub zog siv hluav taws xob muaj tsib ntu, yog tias muab faib ua: lub ntsiab ntawm lub lens electron thiab cov duab kaw, muab tso rau hauv ib qho Lub tshuab nqus tsev los ntawm rab phom electron, daim iav condensing, cov khoom chamber, lub hom phiaj, daim iav diffraction, daim iav nruab nrab, daim iav projection, fluorescent screen thiab lub koob yees duab.
Lub tshuab ntsuas hluav taws xob yog lub tshuab ntsuas hluav taws xob uas siv cov khoom siv hluav taws xob kom pom cov khoom sab hauv lossis saum npoo ntawm cov khoom. Lub wavelength ntawm high-speed electrons yog luv dua li qhov pom lub teeb (yoj-particle dual), thiab qhov kev daws teeb meem ntawm lub tshuab tsom iav yog txwv los ntawm lub wavelength nws siv, yog li qhov theoretical daws teeb meem ntawm electron microscope (txog 0 .1 nanometers) yog siab dua li ntawm lub tshuab ntsuas qhov muag (kwv yees li 200 nanometers).
Ib lub tshuab hluav taws xob xa hluav taws xob (Transmissionelectronmicroscope, abbreviated TEM), lossis kis tau tus mob electron microscope luv luv [1], ua haujlwm ua kom nrawm thiab sib sau ua ke ntawm cov hluav taws xob mus rau cov qauv nyias nyias, qhov twg cov electrons hloov kev coj los ntawm kev sib tsoo nrog atoms hauv cov qauv, ua rau steric kaum scattering. Qhov loj ntawm qhov tawg ntawm lub kaum sab xis yog cuam tshuam nrog qhov ntom thiab tuab ntawm cov qauv, kom cov duab sib txawv thiab cov duab tsaus tuaj yeem tsim, thiab cov duab yuav raug tso tawm ntawm cov khoom siv duab (xws li, phosphor screens, films, thiab photocoupled sib dhos) tom qab magnification thiab tsom.
Vim yog luv luv De Broglie wavelength ntawm electrons, qhov kev daws teeb meem ntawm kis tau tus mob electron microscopy yog ntau dua li ntawm optical microscopy, ncav cuag {{0}}}.1 mus rau 0.2 nm, nrog ib tug magnification ntawm kaum tawm txhiab rau lab lub sij hawm. Yog li ntawd, kev siv lub tshuab hluav taws xob xa hluav taws xob tuaj yeem siv los soj ntsuam cov qauv zoo ntawm cov qauv, lossis txawm tias cov qauv ntawm ib kab ntawm cov atoms, kaum tawm txhiab lub sij hawm me dua li cov qauv me me uas tuaj yeem pom nrog. TEM yog ib qho tseem ceeb analytical txoj kev nyob rau hauv ntau yam kev tshawb fawb muaj feem xyuam rau nruab nrab physics thiab biology, xws li kev tshawb fawb cancer, virology, cov ntaub ntawv science, raws li zoo raws li nanotechnology, semiconductor kev tshawb fawb, thiab hais txog.
Nyob rau hauv qis magnifications, qhov sib piv ntawm TEM imaging yog vim qhov txawv thicknesses thiab compositions ntawm cov ntaub ntawv uas ua rau txawv absorption ntawm electrons. Thaum lub magnification yog siab, complex fluctuation cuam tshuam ua rau sib txawv nyob rau hauv lub brightness ntawm daim duab, thiab yog li ntawd yuav tsum tau muaj kev txawj ntse los soj ntsuam cov resulting duab. Los ntawm kev siv cov qauv sib txawv ntawm TEM, nws muaj peev xwm txheeb xyuas cov qauv los ntawm nws cov khoom siv tshuaj, siv lead ua orientation, cov qauv hluav taws xob, kev hloov hluav taws xob los ntawm cov qauv, thiab cov khoom siv hluav taws xob niaj hnub nqus ntawm cov qauv.
zoo li niaj zaus nqus ntawm electrons rau hauv cov qauv.
Thawj TEM yog tsim los ntawm Max Knorr thiab Ernst Ruska hauv 1931, pawg tshawb fawb no tau tsim thawj TEM nrog kev daws teeb meem tshaj qhov pom lub teeb hauv xyoo 1933, thaum thawj lub lag luam TEM tau tsim hauv 1939.
