Kev Ua Zoo Dua Zaj Dab Tsi Ua Txhim Kho Yam Ntxim Saib Ntxim Ua - Cov Tshuab Cua Tshuab

Kev pom zoo nyias zaj duab xis npaj txhij txog kev siv tshuab - tshuab nqus tsev

Nqus plua plav yog lub hauv paus rau qhov kev npaj ntawm qhov muag yeeb yaj kiab. Tam sim no, feem ntau ntawm cov yeeb yaj kiab nyias yeej npaj tau nyob rau hauv lub tshuab nqus tsev. Daim ntawv no luv luv qhia txog cov kev paub txog kev nqus dej ntsig txog kev kho qhov muag tau zoo nkauj.

1. Discovery ntawm lub tshuab nqus tsev

Nyob rau hauv 1641, Torricelli, tus zauv ntawm Italian, tau ntim cov iav ntev nrog mercury ntawm ib kawg, ces maj mam thawb nws mus rau hauv ib lub thawv uas muaj mercury. Qhov siab tshaj ntawm qhov ntsuas ntawm mercury hauv lub raj yog 76 centimeters. Yog mercury tau hloov nrog dej, qhov siab siab tshaj plaws ntawm kem yog 10.3 meters.

2. Kev txhais thiab chav tsev ntawm lub tshuab nqus tsev

Lub tshuab nqus tsev yog lub hauv paus ntawm qhov chaw ua pa rau ntawm qhov chaw tsawg dua ib qho kev ua kom tsis muaj zog atmospheric. Nqus plua plav feem ntau yog los ntawm lub tshuab nqus tsev, thiab lub tshuab nqus tsev yog ntsuas los ntawm kev siv zog (quab yuam ib cheeb tsam twg). Lub ntsuas kev cai lij choj ntawm siab yog Pascal (Pascal), uas yog ib chav ntawm qhov ntsuas ntawm ib kilogram ib ob. Nws yog qhov system thoob plaws ntiaj teb (SI), los sis Pa, uas tau pom zoo nyob thoob teb chaws tam sim no. Tam sim no, muaj ob peb lub qub qub tseem siv nyob rau hauv cov tswv yim engineering. Kev hloov dua siab tshiab ntawm ob peb qhov chaw qub thiab PASCAL yog raws li nram no:

(1) tus qauv huab cua (ATM):
1 ATM = 1.01325 x 105 pa = 760 Torr.
(2) Torr:
1 ATM Torr = 1/760 = 133.3 Pa.
(3):
1 Bar = 1 ATM = 1000 mbar
(4) mbar:
1 mbar = 7.5 x 10-1 Torr = 100 pa.

3. Lub luag haujlwm ntawm lub tshuab nqus tsev rau hauv plooj plating

Tag nrho cov sij hawm, cov roj molecules yog nyob rau hauv cov hluav taws xob thermal lus tsis txaus, thiab lawv pheej sib txuam nrog ib leeg, thiab nrog rau phab ntsa ntawm lub khob. Raws li cov xeeb ceem, cov pa roj carbon monoxide ntawm cov roj ntim yog li 3 x 1019 / cubic centimeter, txhua cov pa ya rau 1010 zaug ib ob. Cov pa roj carbon monoxide molecules tsis nyob hauv txoj kab ncaj nraim, tab sis nyob hauv txoj kab tawg uas hloov cov kev taw qhia thaum lawv sib tsoo. Yog tias cov yeeb yaj kiab nyob hauv lub chaw zoo li no, cov evaporating hais yuav sib tsoo nrog lwm cov lwg me me thiab hloov lub siab tas mus li, uas yuav ua rau kom muaj qhov tshwm sim ntawm lwm cov tshuaj tiv thaiv nrog, thiab tus nqi evaporation thiab film thickness yuav tsis raug tswj. Yuav kom tsis txhob muaj cov kev tsis zoo, peb yuav tsum ua qhov no rau hauv lub tshuab nqus tsev.

Qhov faib ntawm thaj av nqus tsev. Rau qhov kev sib txuas lus ntawm kev sib tham thiab tswv yim tshiab, lub tshuab nqus tsev feem ntau muab faib mus rau plaub thaj chaw: coarse vacuum (> 103Pa), qis nqus (103 ~ 10-1pa), siab nqus (10-1 ~ 10-6pa) thiab ultra-siab nqus (<> Lub chaw seem ntawm cov roj hmab xau yog kwv yees rau lub xeev atmospheric, thiab lub thermal suab paj nruag ntawm lub cev yog tus cwj pwm tseem ceeb, thiab cov roj yam ntxwv yog qhov kev sib tsoo ntawm cov roj molecules. Cov dej ntws ntawm cov tshuab nqus cov pa roj tsis tshua tawm maj maj hloov los ntawm kev xeev khov khiav mus rau hauv lub xeev molecular flow. Cov roj ntws hauv lub tshuab nqus tsev yog lub cev tsis muaj zog, uas yog qhov sib tsoo ntawm qhov kev sib tsoo ntawm cov roj molecules thiab cov hlab ntsha, thiab kev sib tsoo ntau heev. Cov khoom siv ua vaporized hauv lub tshuab nqus tsev yuav xa hauv kab ncaj ncaj.

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Nqus tsev kawm ntawv qib siab yog qhov qhia tawm ntawm lub thermal cov pa roj carbon monoxide, thiab muaj lwm qhov tshuab "microcosmic" ntawm txoj kev "dawb txoj hauv kev": qhov ze ntawm ob sab sib tsoo ntawm cov pa roj molecules, uas nws qhov nruab nrab yog hu ua "free free path".

Teem lub tebchaws nrug ntawm N0 vaporized particle d, thiab cov naj npawb ntawm cov khoom tsis cuam tshuam los ntawm residual gas yog:

Nd = N0e-d / l (1)
Feem pua ntawm cov molecules collided:

f = 1-nd / N0 = 1-ed / l (2)

Raws li kab zauv (2), thaum txoj kev pheej yig hauv nruab nrab yog sib npaug ntawm txoj kev deb ntawm qhov evaporation mus rau lub hauv paus, 63% ntawm cov hmoov evaporated tsoo. Yog hais tias qhov nruab nrab txoj kev siab tuaj yeem los ntawm ib yam ntawm 10, tus naj npawb ntawm qhov sib tsoo muaj tsawg dua rau 9%. Nws tuaj yeem pom tias sib tsoo yuav raug txo kom tsawg tsuas yog thaum nruab nrab txoj kev ywj pheej muaj ntau dua qhov kev ncua deb ntawm qhov evaporation source mus rau lub hauv paus.

Yog hais tias txoj hauv kev nruab nrab yog qhov loj txaus thiab txaus siab rau qhov mob l, d

F ntaub ntawv d / l (3)
Vim hais tias lx0667 / P (P yog qhov siab).
Hloov kab zauv (4) rau kab (3) kom tau txais: f1.5 (5)

Yuav kom paub meej ntawm qhov zoo ntawm zaj duab xis txheej, cia f ≤ 10-1. Thaum twg qhov kev ncua deb ntawm qhov evaporation source los puag base d = 30cm, P ≤ 2.2 × 10-3pa. Raws li qhov sib npaug (5), qhov loj ntawm lub tshuab nqus tsev ntawm lub tshuab txheej txheem, thiab ntev dua ntawm qhov evaporation thiab qhov substrate yog qhov siab tshaj qhov khoom nqus tsev.

Nqus plua plav yog ob lub luag hauj lwm hauv kev npaj ua daim nyias nyias: ib qho yog txo qhov kev sib tsoo ntawm kev sib tsoo thiab lwm cov khoom siv roj, thiab lwm tus yog ua kom tsis txhob muaj cov tshuaj tiv thaiv ntawm cov evaporating molecules thiab lwm cov roj molecules.

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