Yuav ua li cas ntsuas qhov refractive index
Thaum lub teeb nkag mus rau nruab nrab B los ntawm nruab nrab A, yog tias nruab nrab A yog cov tshuaj hydrophobic mus rau nruab nrab B, uas yog, nA< nP=1/sin is also a constant, and its relationship with the refractive index is: Indicates. Obviously, under a certain wavelength and certain conditions, it can be seen that the refractive index can be obtained by measuring the critical angle, which is the basic optical principle of the commonly used Abbe refractometer.
Txhawm rau ntsuas tus nqi, Abbe refractometer siv txoj kev "ib nrab-lub teeb thiab ib nrab-tsaus", uas yog cia lub teeb monochromatic nkag mus rau nruab nrab B los ntawm nruab nrab A los ntawm txhua lub kaum sab xis ntawm 0-90 degree, ntawm lub sijhawm no, tag nrho lub kaum sab xis tseem ceeb hauv nruab nrab B yog Lub Teeb hla txhua qhov chaw, yog li nws yog qhov kaj; thaum txhua qhov chaw sab nraum lub kaum ntse ntse tsis dhau lub teeb, yog li nws yog qhov tsaus ntuj, thiab thaj tsam ntawm qhov kaj thiab qhov tsaus ntuj yog qhov tseeb heev. Yog tias koj saib nrog ib qho eyepiece saum nruab nrab B, koj tuaj yeem pom cov duab ib nrab tsaus nti nrog ib thaj tsam meej heev.
Qhov nruab nrab yog txawv, lub kaum sab xis tseem ceeb kuj txawv, thiab ciam teb txoj hauj lwm ntawm lub teeb thiab tsaus qhov chaw nyob rau hauv lub eyepiece kuj txawv. Yog hais tias ib tug "hla" kab yog engraved nyob rau hauv lub eyepiece, hloov tus txheeb ze txoj hauj lwm ntawm nruab nrab B thiab lub eyepiece, yog li ntawd txhua lub sij hawm lub ciam teb ntawm lub teeb thiab tsaus qhov chaw ib txwm coincides nrog cov kev sib tshuam ntawm "hloov kab", los ntawm kev ntsuas. nws tus txheeb ze txoj hauj lwm (Lub kaum sab xis) thiab tom qab hloov dua siab tshiab, qhov refractive index yuav tau. Kev nyeem ntawv kos rau ntawm qhov ntsuas ntawm Abbe refractometer yog qhov hloov pauv refractive index, yog li nws tuaj yeem nyeem ncaj qha. Nyob rau tib lub sijhawm, Abbe refractometer muaj cov cuab yeej dispersion-tawm, yog li nws tuaj yeem siv ncaj qha tshav ntuj, thiab cov lej ntsuas yog tib yam li cov ntsuas los ntawm sodium lub teeb. Cov no yog qhov zoo ntawm Abbe refractometer.
Yuav ua li cas siv Abbe refractometer: ua ntej txuas lub refractometer mus rau lub tank qhov kub thiab txias, tom qab qhov kub thiab txias, cais lub kaum sab xis ntawm lub kaum sab xis, thiab maj mam so cov iav sab sauv thiab sab qis nrog ib qho me me ntawm ethanol lossis acetone ntawm lo lo ntxhuav lossis lo ntsiab muag. ntawv. Tom qab cov ethanol los yog acetone evaporates, ntxiv ib tee dej distilled rau daim iav hauv qab no, kaw lub prism, thiab kho daim iav kom pom qhov pom hauv daim iav ci.
Tig lub prism kom txog rau thaum ib tug ciam teb kab los yog ib tug xim lub teeb band tshwm nyob rau hauv daim iav; Yog hais tias lub teeb xim muaj xim tshwm, kho qhov sib txawv kom ua rau thaj tsam ntawm lub teeb thiab tsaus ntuj kom pom tseeb, thiab tom qab ntawd tig lub kaum sab xis prism kom txoj kab ciam teb tshwm sim los ntawm kev sib tshuam ntawm "hla". Sau qhov kev nyeem ntawv thiab qhov kub thiab txias, rov ua dua ob zaug los ntsuas qhov nruab nrab qhov ntsuas qhov ntsuas ntawm cov dej ntshiab thiab muab piv nrog tus qauv tus nqi ntawm cov dej ntshiab (=1.33299), calibration cog ntawm refractometer tuaj yeem tau txais, thiab tom qab ntawd cov refractive index ntawm cov qauv ua kua yuav tsum tau ntsuas nyob rau hauv tib txoj kev. Tus nqi kho feem ntau me me, thiab yog tias tus nqi loj dhau lawm, tag nrho cov cuab yeej yuav tsum tau recalibrated. Cov ntsiab lus hauv qab no yuav tsum tau them sai sai rau thaum siv lub refractometer:
(1) Abbe qhov ntsuas ntau yog los ntawm 1.3000 mus rau 1.7000, thiab qhov tseeb yog ± 0.0001; thaum ntsuas, yuav tsum tau saib xyuas seb qhov ntsuas kub ntawm lub tsho tiv thaiv puas yog. Yog tias koj xav ntsuas rau ± 0.0001, qhov ntsuas kub yuav tsum tau tswj nyob rau hauv thaj tsam ntawm ± 0.1 degree.
(2) Lub ntsuas hluav taws xob yuav tsum tsis txhob raug tshav ntuj thaum siv lossis khaws cia, thiab yuav tsum tau npog nrog daim ntaub dub thaum tsis siv.
(3) Lub prism ntawm lub refractometer yuav tsum tau tiv thaiv kom tsis txhob khawb ntawm daim iav nto. Thaum ntxiv cov kua, qhov kawg ntawm lub dropper yuav tsum tsis txhob kov lub prism.
(4) Daim iav saum npoo yuav tsum tau ntxuav ua ntej txhua qhov poob ntawm cov qauv; Tom qab siv, daim iav saum npoo yuav tsum tau ntxuav nrog acetone los yog 95 feem pua ethanol, thiab lub prism yuav tsum raug kaw tom qab ziab.
(5) Cov kua dej uas corrode los yog yaj lub prism iav, rwb thaiv tsev hlau thiab cov nplaum ntawm lawv yuav tsum raug zam.
Thaum kawg, nws yuav tsum tau taw qhia tias Abbe refractometer tsis tuaj yeem siv ntawm qhov kub siab dua; nws yog ib qho nyuaj rau kev ntsuas cov qauv tsis haum los yog dej-absorbing; Tsis tas li ntawd, qhov yuav tsum tau ua rau purity ntawm cov qauv kuj yog siab. Feem ntau hais lus, thaum qhov kub thiab txias nce los ntawm ib tug degree, qhov refractive index ntawm cov kua organic compound txo los ntawm 3.5 × 10-4 — 5.5 × 10-4. Qee cov kua dej, tshwj xeeb tshaj yog thaum qhov ntsuas kub uas nws qhov ntsuas qhov ntsuas yuav tsum tau nyob ze rau nws qhov kub ntawm qhov kub, muaj qhov ntsuas kub txog li 7 × 10-4. Nyob rau hauv kev ua hauj lwm, lub refractive index ntsuas ntawm ib tug tej yam kub thiab feem ntau hloov mus rau hauv lub refractive index ntawm lwm kub. Rau qhov yooj yim ntawm kev xam, 4.5 × 10-4 feem ntau yog siv raws li qhov kub thiab txias hloov tas li. Tus nqi tau los ntawm qhov kev suav ntxhib no yuav muaj qhov yuam kev me ntsis, tab sis nws yog tus nqi siv. Nyob rau hauv lwm yam lus, lub refractive index txo nrog qhov nce ntawm qhov kub thiab txias, thiab qhov refractive index hloov los ntawm li ntawm 0.00045 rau txhua txhua 1 degree Celsius hloov. Peb tuaj yeem xam qhov ntsuas qhov ntsuas qhov ntsuas qhov ntsuas tau kho rau 20 degree los ntawm cov qauv hauv qab no: nD(t)=nD(20) - 0.00045(t-20 degree )
qhov twg nD(t) yog qhov kev sim ntsuas qhov ntsuas qhov ntsuas ntawm qhov ntsuas kub t. Qhov no qhia tau hais tias thaum qhov kev sim kub siab tshaj 20 degree, nD(20) loj dua nD(t); Thaum qhov kev sim ntsuas kub qis dua 20 degree, nD(20) me dua nD(t).
Piv txwv li: Muab nD(t) =1.3667, t=25.2 degree , xam nD(20).
nD(t)=nD(20) - 0.00045(t-20 degree)
nD(20)=1.3667 plus 0.00045(25.2 degree -20 degree )
{{0}}.3667 ntxiv rau 0.00045 × 5.2
=1.36904 Cov nyhuv ntawm lub teeb wavelength
Lub refractive index ntawm ib yam khoom txawv nrog lub wavelength ntawm lub teeb, nrog ntev wavelengths muaj ib tug me refractive index thiab luv wavelengths muaj ib tug loj refractive index. Lub teeb ci siv rau kev ntsuas feem ntau yog lub teeb dawb. Thaum lub teeb dawb yog refracted los ntawm lub prism thiab cov qauv ua kua, vim qhov sib txawv wavelengths ntawm txhua lub teeb xim, qhov degree ntawm refraction kuj txawv. Tom qab refraction, nws yog decomposed rau hauv ntau yam xim teeb. Qhov tshwm sim no hu ua dispersion. Lub dispersion ntawm lub teeb yuav ua rau cov kab sib faib nruab nrab ntawm lub teeb thiab tsaus ntuj nyob rau hauv qhov chaw ntawm lub zeem muag tsis meej, ua rau kev ntsuas yuam kev. Txhawm rau kom tshem tawm cov dispersion, lub dispersion compensator yog ntsia rau ntawm qhov kawg ntawm qhov kev soj ntsuam raj ntawm Abbe refractometer.
Cov nyhuv ntawm qhov kub thiab txias
Lub refractive index ntawm cov tshuaj hloov pauv nrog qhov kub thiab txias, qhov refractive index txo qis thaum kub nce, thiab nce raws li qhov kub thiab txias. Qhov ntsuas ntawm lub refractometer yog engraved ntawm tus qauv kub ntawm 20 degree. Yog li ntawd, nws yog qhov zoo tshaj los ntsuas qhov ntsuas qhov ntsuas ntawm 20 degree. Txwv tsis pub, kev kho qhov kub thiab txias yuav tsum tau ua ntawm qhov ntsuas ntsuas. Thaum nws tshaj 20 degree, ntxiv tus lej kho; thaum nws qis dua 20 degree, rho tawm tus lej kho
