Lub ib nrab-lub neej ntawm uranium: lub ntsiab yam ntxwv thiab daim ntawv thov

Kawm phenomenon ntawm radioactivity, ib tus paub txog yog hais txog qhov no tseem ceeb tshaj plaws yam ntxwv raws li lub ib nrab-lub neej. Raws li koj paub, txoj cai ntawm tej lwj hais tias txhua txhua ob nyob rau hauv lub ntiaj teb no muaj ib tug disintegration ntawm atoms, thiab cov quantitative cov yam ntxwv ntawm cov dab yog ncaj qha mus txuas nrog rau cov naj npawb ntawm cov atoms. Yog hais tias ib tug tej lub sij hawm ntawm lub sij hawm yuav lwj ib nrab ntawm tag nrho cov muaj nyob rau naj npawb ntawm cov atoms, cov hniav lwj ½ ntawm qhov seem uas atoms yuav tsum tau kom tus nqi qub lub sij hawm. Nws yog lub sij hawm no lub sij hawm no yog hu ua ib nrab-lub neej. Txawv hais nws txawv - los ntawm thousandths ntawm milliseconds rau billions ntawm xyoo, raws li, piv txwv li, nyob rau hauv lub rooj plaub thaum nws los txog rau pro-lub neej sij hawm ntawm uranium.

Uranium yog lub heaviest ntawm tag nrho cov uas twb muaj lawm hais nyob rau hauv lub xeev ntuj nyob rau hauv lub ntiaj teb no, nws yog feem ntau cov feem ntau zoo nkauj kwv rau txoj kev tshawb no ntawm radioactivity txheej txheem. Qhov no lub caij sab nyob rau hauv 1789 los ntawm tus German tus paub txog M. Klaproth, uas hu nws nyob rau hauv Honor ntawm tus nyuam qhuav nrhiav tau lub ntiaj teb Uranus. Qhov tseeb hais tias uranium yog tej, nws twb ntawd nyob rau tom kawg ntawm lub XIX xyoo pua los ntawm qhov Fabkis chemist A. Becquerel.

Lub ib nrab-lub neej ntawm uranium xam siv tib lub mis li cov coj sij hawm nyob rau hauv lwm yam tej ntsiab:

T_ {1/2} = au ln 2 = frac {ln 2} {lambda},

qhov twg «au» - qhov nruab nrab lub neej ntawm ib tug atom, «lambda» - lub ntsiab lwj tas li. Txij li thaum haujlwm uas yog COy 2 sib npaug zos rau txog 0.7, ib nrab-lub neej ntawm xwb 30% nyob rau hauv nruab nrab luv dua tag nrho lub neej atom.

Txawm tias muaj tseeb hais tias rau hnub tim, 14 zaum paub isotopes ntawm uranium nyob rau hauv lawv qhov tshwm sim tsuas yog peb: uranium-234, uranium-235 thiab uranium-238. Lub ib nrab-lub neej ntawm uranium yog sib txawv: cov ntaub ntawv rau U-234 nws yog "tsuas" 270 txhiab xyoo, thiab ib tug ib nrab-lub neej ntawm uranium-238 tshaj 4.5 billion. uranium-235 ib nrab-lub neej yog nyob rau hauv lub "golden mean" - 710 lab lub xyoo.

Nws yuav tsum tau muab sau tseg hais tias uranium radioactivity nyob rau hauv vivo yog siab txaus, piv txwv li, ib tug photographic phaj mus rau lub teeb nyob rau tib lub sij hawm. Nyob rau tib lub sij hawm nws yog tsim nyog sau cia hais tias nyob rau hauv tag nrho cov uranium isotope U-235 yog tsuas haum rau qhov siv thiab ua cov ntsaws rau ib tug nuclear foob pob. Qhov no yog hais tias cov uranium-235 ib nrab-lub neej nyob rau hauv ib tug muaj ib puag ncig yog tsawg mob siab heev tshaj nws "cov kwv tij", thiab yog li ntawd cov qhov tso zis tsis tseem ceeb neutrons yog tsawg heev.

uranium-238, ib nrab-lub neej yog ho ntau tshaj 4 billion xyoo, Txawm li cas los, thiab nws yog tam sim no dav siv nyob rau hauv lub nuclear kev lag luam. Yog li ntawd raws li mus pib ib lub saw tshuaj tiv thaiv ntawm fission ntawm hnyav nuclei ntawm no caij yuav ib tug tseem ceeb npaum li cas ntawm neutron zog. 238 yog siv raws li kev tiv thaiv nyob rau hauv fission thiab fusion pab kiag li lawm. Txawm li cas los, feem ntau ntawm cov muab rho uranium-238 yog siv rau cov synthesis ntawm plutonium siv nyob rau hauv nuclear riam phom.

Lub duration ntawm lub ib nrab-lub neej ntawm uranium zaum siv los mus laij lub hnub nyoog ntawm tus neeg minerals thiab ntawm lub saum ntuj ceeb tsheej lub cev nyob rau hauv feem ntau. Uranium ntoos yog haum universal mechanism rau tej suav. Nyob rau tib lub sij hawm uas lub hnub nyoog twb tau xam ntau dua los yog tsawg meej, nws yog tsim nyog los paub tsis tau tsuas yog tus nqi ntawm cov uranium nyob rau hauv sib txawv breeds, tab sis kuj tus piv ntawm uranium thiab ua raws li qhov kawg khoom, uas hloov dua siab tshiab lub uranium nucleus.

Muaj yog ib txoj kev los mus laij lub pob zeb thiab minerals, nws yog txuam nrog qhov thiaj li hu ua txawj fission ntawm uranium. Raws li yog paub zoo tias, raws li ib tug tshwm sim ntawm cov txawj fission ntawm uranium nyob rau hauv tej yam ntuj tso tej yam kev mob ntawm ib tug particle nrog enormous quab yuam bombarded ib tug xov tooj yog tshuaj, tawm hauv ib co kua nplaum ntawm ib tug tshwj xeeb - lem.

Nws yog rau tus naj npawb ntawm cov ciav hlau, paub ib nrab-lub neej sij hawm ntawm uranium, thiab zaum xaus lus hais txog lub hnub nyoog ntawm ib tug nruj heev lub cev - seb nws yog ib qho ancient yug menyuam, los yog ib tug kuj "hluas" hub. Qhov no yog hais tias muaj hnub nyoog ntawm ib tug kwv yog ncaj qha xwm yeem mus rau ntau ntsuas ntawm uranium atoms, uas bombarded nws cov tub ntxhais.