2024 Tus sau: Elizabeth Oswald | [email protected]. Kawg hloov kho: 2024-01-13 00:07
Nyob rau hauv qhov tsis muaj dielectric, qhov poob ntawm lub zog yuav tsis tshwm sim. Yog li lub attenuation yuav be zero.
Dab tsi yog qhov poob tsis muaj dielectric?
Ib qhov nruab nrab lossless yog a nruab nrab nrog xoom conductivity thiab finite permeability thiab permittivity. Thaum lub electromagnetic yoj propagates los ntawm ib tug lossless nruab nrab, lub amplitude ntawm nws hluav taws xob teb los yog magnetic teb tseem nyob tas mus li thoob plaws hauv lub propagation.
Yuav ua li cas yog ib tug lossy dielectric sawv cev?
Ib qhov nruab nrab dielectric yog txhais tau tias yog qhov nruab nrab uas cov hluav taws xob conductivity tsis sib npaug rau xoom tsis tau nws tsis yog tus neeg xyuas pib zoo. Kev teeb tsa σ ≠ 0 hauv Equation 1.12 ua rau tsis muaj xoom attenuation tas li (α ≠ 0).
Dab tsi yog qhov sib txawv ntawm qhov tsis muaj qhov tsis zoo thiab tsis muaj hluav taws xob?
Ib lub dielectric poob yog qhov nruab nrab uas EM nthwv dej poob lub zog thaum nws nthuav tawm vim qhov tsis zoo. Nyob rau hauv lwm yam lus, ib tug lossy dielectric yog ib feem ntawm qhov nruab nrab (iperfect dielectric los yog imperfect conductor) nrog ib tug =0, raws li txawv los ntawm ib tug lossless dielectric (zoo meej los yog zoo dielectric) nyob rau hauv uas a=0.
Dab tsi yog qhov poob tangent hauv electromagnetic theory?
Kev piav qhia: Qhov poob tangent yog ntsuas qhov poob ntawm lub zog vim kev nthuav tawm hauv dielectric, thaum piv rau hauv tus neeg xyuas pib. Li no nws kuj tseem hu ua dissipation factor.
Pom zoo:
Qhov twg yog qhov tsis muaj lossis tsis muaj?
lub xeev tsis muaj Qhov twg yog qhov tsis muaj lossis tsis muaj? Raws li lub npe qhov txawv ntawm qhov tsis muaj thiab tsis muaj. yog tsis muaj yog lub xeev tsis muaj thaum tsis muaj yog tsis muaj. Puas tsis muaj lo lus tiag? adj.
Yuav ua li cas txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau pom kev pom?
Txawm li cas los xij, corneal collagen cross-linking - cov txheej txheem qib siab tau pom zoo los ntawm US Food and Drug Administration (FDA) hauv xyoo 2016 - tuaj yeem txhim kho qhov pom kev hauv cov neeg mob txhua hnub nyoog. Corneal collagen cross-linking (CXL) tsis yog kho rau keratoconus, tab sis nws tuaj yeem pab tiv thaiv tus mob kom tsis txhob mob hnyav.
Vim li cas ho tsis ya mus rau sab hnub poob mus rau sab hnub poob tseem ceeb?
Southwest Airlines tau hais rau hnub Thursday nws yuav tsum tsis ua haujlwm hauv peb lub nroog, suav nrog Key West. "Hmoov tsis zoo,theem ntawm kev thov hauv zos tsis tso cai rau Southwest kom tau txais txiaj ntsig zoo rau cov lag luam no,"
Vim li cas qhov tseem ceeb ntawm qhov muaj zog thiab qhov tsis muaj zog yog qhov tseem ceeb?
Nws yog ib qho tseem ceeb rau qhov tseem ceeb ntawm qhov ua tau zoo thiab qhov tsis muaj zog vim qhov no pab lub tuam txhab txiav txim siab txog thaj chaw uas lawv yuav tsum tau txhim kho ntxiv rau thaj chaw uas lawv ua tau zoo hauv. Vim li cas lub zog thiab qhov tsis muaj zog tseem ceeb?
Leej twg hais tias tsis muaj kev cia siab tsis muaj kev poob siab?
Quote los ntawm Eric Jerome Dickey: "tsis muaj kev cia siab, tsis muaj kev poob siab!" Yuav tsis muaj kev cia siab tsis muaj kev poob siab txhais li cas? Thaum peb txais qhov tseeb tsis muaj kev cia siab, tsis muaj kev poob siab, peb pib ua neej nyob rau tam sim no.
