Phenomena xws li dielectric susceptibility thiab permittivity pom tsis tau tsuas yog nyob rau hauv physics, tab sis kuj nyob rau hauv lub neej txhua hnub. Hauv qhov no, nws yog ib qho tsim nyog los txiav txim siab lub ntsiab lus ntawm cov xwm txheej no hauv kev tshawb fawb, lawv lub zog thiab kev siv hauv lub neej txhua hnub.
Kev txiav txim siab nruj
Kev siv zog yog vector kom muaj nuj nqis hauv physics, uas yog xam los ntawm lub zog uas cuam tshuam rau ib qho txiaj ntsig zoo tso rau ntawm qhov chaw hauv kev kawm. Tom qab lub dielectric muab tso rau hauv ib qho chaw sab nraud electrostatic, nws tau txais lub sijhawm dipole, hauv lwm lo lus, nws dhau los ua polarized. Txhawm rau piav qhia ntau npaum li cas polarization hauv dielectric, polarization yog siv - vector lub cev ntsuas ntsuas raws li lub sijhawm dipole ntawm qhov ntim tus nqi ntawm dielectric.
Qhov kev siv vector tom qab dhau los ntawm lub ntsej muag ntawm ob lub dielectrics tau hloov pauv sai, ua rau muaj kev cuam tshuam thaum suav cov teb electrostatic. Hauv qhov no, tus yam ntxwv ntxiv yog qhia - vectorhluav taws xob hloov chaw.
Siv qhov kev tso cai, koj tuaj yeem paub tias pes tsawg zaus lub dielectric tuaj yeem ua rau sab nraud tsis muaj zog. Yuav kom piav qhia txog cov khoom siv hluav taws xob feem ntau hauv cov dielectrics, cov hluav taws xob hloov hluav taws xob yog siv.
Basic definitions
Qhov kev pom zoo ntawm qhov nruab nrab yog ib qho coefficient uas suav nrog hauv lej cim ntawm Coulomb txoj cai lij choj thiab qhov sib npaug ntawm kev sib raug zoo ntawm lub zog hluav taws xob thiab hluav taws xob induction. Qhov tseeb permittivity tuaj yeem sawv cev raws li cov khoom ntawm cov txheeb ze permittivity ntawm nruab nrab thiab hluav taws xob tas li.
Dielectric susceptibility, hu ua polarizability ntawm ib yam khoom, yog lub cev muaj nuj nqis uas tuaj yeem ua polarized nyob rau hauv lub zog ntawm hluav taws xob teb. Nws kuj yog cov coefficient ntawm linear kev twb kev txuas ntawm sab nraud hluav taws xob teb nrog lub polarization ntawm dielectric nyob rau hauv ib tug me me teb. Cov mis rau dielectric susceptibility yog sau li: X=na.
Feem ntau, dielectrics muaj qhov zoo dielectric susceptibility, thaum tus nqi no yog dimensionless.
Ferroelectricity yog lub cev tshwm sim muaj nyob rau hauv qee yam muaju, hu ua ferroelectrics, ntawm qee qhov ntsuas kub. Nws muaj nyob rau hauv cov tsos ntawm spontaneous polarization nyob rau hauv ib tug siv lead ua txawm tsis muaj hluav taws xob sab nraud. Qhov sib txawv ntawm ferroelectrics thiab pyroelectrics yoguas nyob rau hauv tej qhov kub thiab txias ranges lawv hloov pauv siv lead ua, thiab random polarization ploj.
Cov hluav taws xob hauv thaj chaw tsis coj tus cwj pwm zoo li cov neeg coj, tab sis lawv muaj cov yam ntxwv zoo sib xws. Lub dielectric sib txawv ntawm tus neeg xyuas pib thaum tsis muaj cov khoom thauj dawb. Lawv nyob ntawd, tab sis nyob rau hauv tsawg heev. Nyob rau hauv ib tug neeg xyuas pib, ib tug electron txav mus los nyob rau hauv lub siv lead ua lattice ntawm ib tug hlau yuav ua tau ib tug zoo xws li cov cab kuj. Txawm li cas los xij, electrons hauv dielectric yog sib koom ua ke rau lawv tus kheej atoms thiab tsis tuaj yeem txav tau yooj yim. Tom qab kev taw qhia ntawm dielectrics rau hauv ib qho chaw nrog hluav taws xob, hluav taws xob tshwm sim hauv nws, zoo li tus neeg xyuas pib. Qhov sib txawv ntawm ib lub dielectric yog tias cov hluav taws xob tsis txav mus los ntawm lub ntim, zoo li nws ua hauv ib tus neeg xyuas pib. Txawm li cas los xij, nyob rau hauv kev cuam tshuam ntawm sab nraud hluav taws xob, qhov kev hloov pauv me ntsis tshwm sim los ntawm sab hauv cov khoom siv hluav taws xob: ib qho zoo yuav raug hloov mus rau hauv kev coj ua ntawm thaj teb, thiab qhov tsis zoo yuav ua rau lwm tus.
Nyob rau hauv qhov no, qhov chaw tau txais ib qho nqi. Cov txheej txheem rau cov tsos ntawm tus nqi ntawm cov khoom nyob rau hauv lub zog ntawm hluav taws xob teb yog hu ua dielectric polarization. Yog hais tias nyob rau hauv ib tug homogeneous thiab nonpolar dielectric nrog ib tug tej yam concentration ntawm molecules tag nrho cov hais yog tib yam, ces lub polarization kuj yuav zoo ib yam. Thiab nyob rau hauv cov ntaub ntawv ntawm dielectric susceptibility ntawm lub dielectric, tus nqi no yuav dimensionless.
Tus nqi sib tw
Vim yog cov txheej txheem ntawm polarization, cov nqi tsis them nyiaj tshwm sim nyob rau hauv lub ntim ntawm cov khoom siv hluav taws xob, hu ua polarization lossis khi. hais,muaj cov nqi no, tam sim no nyob rau hauv cov nqi ntawm cov molecules thiab, nyob rau hauv lub cuam tshuam ntawm ib tug sab nraud hluav taws xob teb, raug tshem tawm ntawm lub equilibrium txoj hauj lwm yam tsis tau tawm hauv lub molecule nyob rau hauv uas lawv nyob.
Cov nqi sib tw yog tus cwj pwm los ntawm qhov ntom ntom. Lub dielectric susceptibility thiab permeability ntawm qhov nruab nrab txiav txim siab pes tsawg zaus ntawm kev sib khi quab yuam ntawm ob qhov hluav taws xob hauv qhov chaw tsawg dua li qhov ntsuas tib yam hauv lub tshuab nqus tsev.
Tus txheeb ze huab cua susceptibility thiab permeability ntawm feem ntau lwm yam gases nyob rau hauv tus qauv tej yam kev mob nyob ze rau kev sib sau (vim lub dav hlau me). Tus txheeb ze dielectric susceptibility thiab permittivity nyob rau hauv ferroelectrics yog kaum thiab pua pua txhiab ntawm qhov sib cais nto ntawm ib khub ntawm dielectrics nrog txawv kiag li permittivity thiab susceptibility ntawm cov khoom, raws li zoo raws li sib npaug tangential zog Cheebtsam ntawm lawv.
Ntawm ntau qhov xwm txheej, muaj lub rooj sib tham nrog kev hloov pauv ntawm lub cev tam sim no los ntawm lub cev hlau mus rau lub ntiaj teb ib puag ncig, thaum qhov tshwj xeeb conductivity ntawm tom kawg yog ob peb zaug tsawg dua qhov conductivity ntawm lub cev no. Cov xwm txheej zoo sib xws tuaj yeem tshwm sim, piv txwv li, thaum lub sijhawm dhau los ntawm cov hlau electrodes faus rau hauv av. Feem ntau siv steel electrodes. Yog hais tias txoj hauj lwm yog los txiav txim siab lub dielectric susceptibility ntawm iav, ces txoj hauj lwm yuav nyuaj me ntsis los ntawm qhov tseeb hais tias cov khoom no muaj ib tug ion-txo cov cuab yeej, vim hais tias ib tug me me.kev nyuaj siab.
Ntawm tus ciam teb ntawm ib khub ntawm dielectrics nrog sib txawv permeabilities nyob rau hauv lub xub ntiag ntawm sab nraud teb, polarization nqi tshwm sim nrog txawv indices nrog txawv deg ntom. Qhov no yog li cas tus mob tshiab rau lub refraction ntawm kab teb thaum lub sij hawm hloov ntawm ib tug dielectric mus rau lwm tus yog tau.
Txoj cai ntawm refraction nyob rau hauv cov ntaub ntawv ntawm cov kab tam sim no nyob rau hauv nws daim ntawv yuav xam tau tias zoo ib yam li txoj cai ntawm refraction ntawm xaav kab nyob rau hauv lub verge ntawm ob dielectrics nyob rau hauv electrostatic teb.
Txhua lub cev thiab cov khoom ntawm lub ntiaj teb ib puag ncig muaj qee yam khoom siv hluav taws xob. Yog vim li cas rau qhov no nyob rau hauv lub molecular thiab atomic qauv - lub xub ntiag ntawm them hais uas nyob rau hauv ib tug interconnected los yog dawb lub xeev.
Yog tias cov khoom tsis cuam tshuam los ntawm ib qho chaw sab nraud, ces cov khoom no nyob, sib npaug sib npaug, hauv tag nrho cov ntim tag nrho, tsis tsim cov hluav taws xob ntxiv. Yog tias muaj kev siv hluav taws xob hluav taws xob los ntawm sab nraud, kev faib tawm ntawm cov nqi rov qab yuav tshwm sim hauv cov molecules thiab atoms uas twb muaj lawm, uas yuav ua rau pom nws tus kheej sab hauv, uas yuav raug coj mus rau sab nraud.
Thaum xaiv cov ntawv thov sab nraud li E0, thiab sab hauv E', ces tag nrho daim teb E yuav yog cov lej ntawm cov txiaj ntsig no.
Txhua yam khoom hauv hluav taws xob feem ntau muab faib ua:
- tus neeg ua haujlwm;
- dielectrics.
Qhov kev faib tawm no tau muaj nyob rau lub sijhawm ntev, tab sis tsis yog qhov tseeb, txij li kev tshawb fawb tau tshawb pom ntev lub cev nrog cov tshiab lossis ua keProperties of matter.
Cov neeg ua haujlwm
Raws li cov khoom siv hluav taws xob tuaj yeem yog xov xwm uas muaj nqi dawb. Cov hlau feem ntau suav hais tias yog cov teeb meem zoo li no, vim tias lawv cov qauv qhia qhov tsis tu ncua ntawm cov hluav taws xob dawb uas tuaj yeem txav mus rau hauv tag nrho cov kab noj hniav ntawm cov khoom. Lub dielectric susceptibility ntawm nruab nrab tso cai rau koj los ua tus koom nrog hauv cov txheej txheem thermal
Yog tias tus neeg xyuas pib raug cais tawm ntawm qhov cuam tshuam ntawm qhov hluav taws xob sab nraud, ces qhov sib npaug tshwm hauv nws ntawm qhov zoo thiab qhov tsis zoo. Lub xeev no tam sim ntawd ploj mus thaum tus neeg xyuas pib tshwm nyob rau hauv qhov hluav taws xob, uas rov faib cov khoom siv hluav taws xob nrog nws lub zog thiab ua rau lub ntsej muag tsis sib npaug nrog tus nqi zoo thiab tsis zoo rau sab nrauv
Qhov tshwm sim no hu ua electrostatic induction. Cov nqi uas tau tshwm sim nyob rau hauv nws qhov kev txiav txim ntawm qhov chaw ntawm cov hlau yog hu ua induction nqi.
Cov nqi inductive uas tau tshwm sim hauv tus neeg xyuas pib tsim lawv tus kheej daim teb, uas them nyiaj rau kev cuam tshuam ntawm sab nraud sab hauv tus neeg xyuas pib. Hauv qhov no, qhov taw qhia ntawm tag nrho cov electrostatic teb yuav raug them thiab sib npaug rau 0. Qhov muaj peev xwm ntawm txhua qhov taw qhia sab hauv thiab sab nraud yog sib npaug.
Cov txiaj ntsig no qhia tau tias hauv tus neeg xyuas pib (txawm tias muaj kev sib txuas sab nraud) tsis muaj qhov sib txawv ntawm qhov muaj peev xwm thiab tsis muaj electrostatic teb. Qhov tseeb no yog siv los tiv thaiv vim kev sivtxoj kev tiv thaiv electro-optical ntawm ib tug neeg thiab cov khoom siv hluav taws xob rhiab rau thaj chaw, tshwj xeeb tshaj yog cov cuab yeej ntsuas siab thiab microprocessor technology.
Kuj tseem muaj kev sib txuas ntawm kev tso cai thiab kev cuam tshuam. Txawm li cas los xij, nws tuaj yeem hais tau siv tus qauv. Yog li kev sib raug zoo ntawm dielectric tas li thiab dielectric susceptibility muaj cov lus hauv qab no: e=1 + X.
ESD txoj cai
Nrog kev pab los ntawm kev tiv thaiv, khaub ncaws thiab khau ua los ntawm cov khoom siv nrog cov khoom siv hluav taws xob, nrog rau cov kaus mom, yog siv rau hauv kev lag luam hluav taws xob rau kev nyab xeeb ntawm cov neeg ua haujlwm hauv cov xwm txheej ntawm kev kub ntxhov provoked los ntawm high-voltage cov cuab yeej. Electrostatic teb tsis nkag mus rau hauv tus neeg xyuas pib, vim tias thaum tus neeg xyuas pib nkag mus rau hauv qhov hluav taws xob, nws yuav raug them nyiaj los ntawm thaj teb uas tshwm sim vim qhov kev txav ntawm tus nqi dawb.
Dielectrics
Lub npe no yog cov khoom uas muaj cov khoom zoo. Lawv tsuas muaj cov nqi sib txuas, tsis yog dawb xwb. Txhua qhov zoo hauv lawv yuav raug khi rau qhov tsis zoo hauv lub atom nrog cov nqi nruab nrab yam tsis muaj kev txav mus los. Lawv raug faib los ntawm sab hauv dielectrics thiab tsis tuaj yeem hloov lawv txoj haujlwm raws li kev cuam tshuam ntawm sab nraud. Nyob rau tib lub sijhawm, lub dielectric susceptibility ntawm cov khoom thiab lub zog tshwm sim tseem muaj qee qhov kev hloov pauv hauv cov qauv ntawm cov khoom. Los ntawm sab hauv lub atom thiab molecule, qhov ratio hloovCov nqi zoo thiab tsis zoo ntawm cov khoom siv, thiab cov nqi sib txuas ntxiv uas tsis sib haum xeeb tshwm sim ntawm qhov chaw ntawm cov khoom, tsim kom muaj hluav taws xob sab hauv. Nws yog qhia rau qhov nro thov los ntawm sab nraud.
qhov tshwm sim no hu ua dielectric polarization. Nws tuaj yeem ua tus cwj pwm los ntawm qhov tseeb tias qhov hluav taws xob tshwm sim los ntawm sab hauv cov khoom, tshwm sim los ntawm kev cuam tshuam ntawm lub zog sab nraud, tab sis tsis muaj zog los ntawm kev tawm tsam ntawm sab hauv.
Type of polarization
Inside dielectrics, nws tuaj yeem sawv cev los ntawm ob hom:
- kev qhia;
- electronic.
thawj hom kuj muaj lub npe ntxiv - dipole polarization. Cov cuab yeej no muaj nyob rau hauv dielectrics nrog cov chaw hloov chaw ntawm qhov zoo thiab qhov tsis zoo, uas tsim cov molecules los ntawm cov dipoles me me - qhov nruab nrab ntawm ib khub ntawm cov nqi. Qhov tshwm sim no yog ib yam rau cov kua, hydrogen sulfide, nqa nitrogen.
Yog tsis muaj kev cuam tshuam ntawm sab nraud hluav taws xob hauv cov khoom no, molecular dipoles yog taw qhia los ntawm qhov kev hloov pauv kub uas twb muaj lawm, thaum hluav taws xob tsis tshwm sim sab nraud ntawm dielectric.
Daim duab no hloov pauv raws li qhov kev txiav txim ntawm lub zog siv los ntawm sab nraud, thaum cov dipoles tsis hloov lawv txoj kev taw qhia ntau thiab tsis tau them nyiaj macroscopic bound tsub kom tshwm sim rau saum npoo, tsim ib thaj teb nrog kev coj mus rau sab nraud.
hluav taws xob polarization, elasticmechanism
qhov tshwm sim no tshwm sim hauv cov tsis-polar dielectrics - cov ntaub ntawv ntawm ib hom sib txawv nrog cov molecules uas tsis muaj lub sijhawm dipole, uas, nyob rau hauv qhov kev txiav txim ntawm sab nraud teb, yog deformed kom tsuas yog cov nqi zoo yog taw qhia hauv kev taw qhia ntawm sab nraud vector, thiab cov nqi tsis zoo - nyob rau hauv qhov opposite direction.
Vim li ntawd, txhua lub molecule ua haujlwm raws li hluav taws xob dipole taw qhia raws lub axis ntawm daim ntawv thov sab nraud. Nyob rau hauv ib txoj kev zoo sib xws, ib daim teb tshwm nyob rau sab nrauv, uas muaj qhov sib txawv.
Polarization ntawm tsis-polar dielectric
Rau cov tshuaj no, kev hloov pauv ntawm cov molecules thiab cov polarization tom ntej los ntawm kev cuam tshuam ntawm thaj chaw sab nraud tsis yog nyob ntawm lawv qhov txav ntawm qhov kub thiab txias. Methane CH4 tuaj yeem siv los ua cov tsis muaj polar dielectric. Tus lej ntsuas ntawm qhov chaw sab hauv rau ob qho tib si dielectrics yuav pib hloov pauv hauv qhov loj ntawm qhov sib piv rau qhov kev hloov pauv ntawm sab nraud, thiab tom qab saturation, cov teebmeem ntawm hom nonlinear tshwm sim. Lawv tshwm sim thaum txhua molecular dipole yog lined nyob rau hauv cov kab ntawm quab yuam nyob ze polar dielectrics, los yog kev hloov nyob rau hauv tsis-polar tshuaj tshwm sim, tshwm sim los ntawm ib tug muaj zog deformation ntawm atoms thiab molecules los ntawm ib tug loj npaum li cas ntawm lub zog siv los ntawm sab nraud. Hauv qhov ua tau, qhov no tshwm sim tsis tshua muaj tshwm sim.
Dielectric Constant
Ntawm cov ntaub ntawv insulating, lub luag haujlwm tseem ceeb yog muab rau cov ntsuas hluav taws xob thiab cov yam ntxwv zoo li dielectric tas li. Ob leeg raug txiav txim los ntawm ob yam sib txawv:
- tus nqi tiag;
- txheeb ze taw qhia.
Lub sij hawm tsis muaj kev tso cai ntawm ib yam khoom yog hais txog lej cim ntawm Coulomb txoj cai. Nrog nws txoj kev pab, kev sib raug zoo ntawm induction vector thiab qhov siv tau piav qhia nyob rau hauv daim ntawv ntawm coefficient.
