Nyuam qhuav pib, peb tau tshuaj xyuas seb cov thev naus laus zis thev naus laus zis tab tom txhim kho li cas, cov riam phom laser twg tuaj yeem tsim los siv rau hauv kev txaus siab ntawm cov tub rog, hauv av thiab tiv thaiv huab cua, thiab tub rog.
Tam sim no peb yuav tsum nkag siab seb nws puas tuaj yeem tiv thaiv nws, thiab ua li cas. Nws tau hais ntau zaus tias nws txaus los npog lub foob pob hluav taws nrog daim iav txheej lossis txhuam cov projectile, tab sis hmoov tsis, txhua yam tsis yooj yim li.
Ib daim iav uas muaj txhuas-txheej txheej cuam tshuam txog 95% ntawm qhov tshwm sim hluav taws xob, thiab nws qhov ua tau zoo yog nyob ntawm qhov nthwv dej.
Ntawm tag nrho cov ntaub ntawv qhia hauv kab ntawv, txhuas muaj qhov cuam tshuam ntau tshaj plaws, uas tsis yog txhais tau tias yog cov khoom siv hluav taws xob. Yog tias, thaum raug rau lub zog hluav taws xob qis, daim iav ua kom sov me ntsis, tom qab ntawd thaum muaj hluav taws xob muaj zog tsoo, cov khoom ntawm daim iav txheej yuav dhau los ua tsis siv tau, uas yuav ua rau muaj kev puas tsuaj hauv nws cov khoom cuam tshuam thiab ntxiv avalanche zoo li cua sov thiab kev puas tsuaj
Ntawm qhov nthwv dej tsawg dua 200 nm, qhov ua tau zoo ntawm tsom iav poob qis; tiv thaiv ultraviolet lossis X-ray hluav taws xob (tsis siv hluav taws xob laser) qhov kev tiv thaiv no yuav tsis ua haujlwm hlo li.
Muaj kev sim cov khoom siv dag nrog 100% kev xav, tab sis lawv tsuas yog ua haujlwm rau qee qhov nthwv dej. Tsis tas li, tsom iav tuaj yeem npog nrog tshwj xeeb txheej txheej uas ua rau lawv qhov kev xav tau txog 99.999%. Tab sis txoj hauv kev no tseem ua haujlwm rau tsuas yog ib nthwv dej, thiab xwm txheej ntawm lub kaum ntse ntse.
Tsis txhob hnov qab tias kev ua haujlwm ntawm kev siv riam phom nyob deb ntawm kev sim, piv txwv li daim iav foob pob hluav taws lossis lub foob pob hluav taws yuav tsum tau muab ntim rau hauv lub ntim uas muaj cov pa roj inert. Cov cua daj cua dub me me los yog av nplaum, xws li los ntawm hneev tes, yuav cuam tshuam qhov cuam tshuam ntawm daim iav tam sim ntawd.
Tawm ntawm lub ntim yuav nthuav tawm daim iav nto rau ib puag ncig - huab cua thiab cua sov. Yog tias daim iav saum npoo tsis tau npog nrog zaj duab xis tiv thaiv, qhov no tam sim ntawd yuav ua rau muaj kev puas tsuaj ntawm nws cov khoom siv rov ua dua, thiab yog tias nws tau lo nrog txheej txheej tiv thaiv, nws yuav ua rau lub cev tsis zoo dua qub.
Cov lus piav qhia saum toj no, peb nco tias daim iav tiv thaiv tsis zoo heev rau kev tiv thaiv riam phom laser. Thiab yog dab tsi haum?
Rau qee qhov, txoj hauv kev "smearing" lub zog cua sov ntawm lub tshuab hluav taws xob laser hla lub cev los ntawm kev muab cov lus tsa suab tig ntawm lub dav hlau (AC) nyob ib puag ncig nws tus kheej txoj kab ntev yuav pab tau. Tab sis txoj hauv kev no tsuas yog tsim rau cov mos txwv thiab rau qhov txwv rau cov tsheb tsis muaj neeg tsav dav hlau (UAVs), kom tsawg dua nws yuav muaj txiaj ntsig zoo thaum lub tshuab hluav taws xob tawg mus rau hauv ntej ntawm lub hull.
Ntawm qee yam ntawm cov khoom tiv thaiv, piv txwv li, ntawm cov foob pob tawg, foob pob hluav taws cruise (CR), lossis cov foob pob hluav taws tiv thaiv lub tank (ATGM) tua lub hom phiaj thaum ya los saum toj no, txoj hauv kev no tseem siv tsis tau. Tsis tig, rau feem ntau, yog cov tshuaj khib nyiab. Nws nyuaj rau sau cov ntaub ntawv ntawm txhua lub dav hlau tsis tig, tab sis kuv paub tseeb tias muaj ntau ntawm lawv.
Txawm li cas los xij, kev sib hloov ntawm lub dav hlau yuav tsuas yog txo qis me ntsis ntawm cov hluav taws xob laser ntawm lub hom phiaj, vim tiastshav kub kis los ntawm lub zog hluav taws xob laser mus rau lub cev yuav raug xa mus rau cov txheej txheem sab hauv thiab txuas ntxiv mus rau txhua qhov khoom siv hauv lub dav hlau.
Kev siv cov pa taws thiab lub tshuab nqus pa raws li kev tawm tsam tiv thaiv riam phom laser kuj tseem txwv. Raws li tau hais hauv kab lus ntawm kab ntawv, kev siv lasers tiv thaiv cov tsheb hauv av lossis cov nkoj tuaj yeem tsuas yog siv thaum tiv thaiv cov cuab yeej saib xyuas, kom tiv thaiv uas peb yuav rov qab los tom qab. Nws yog qhov tsis muaj tseeb los hlawv lub hull ntawm cov tub rog sib ntaus lub tsheb / lub tank lossis lub nkoj nto nrog lub teeb ci laser nyob rau yav tom ntej.
Tau kawg, nws tsis tuaj yeem thov haus luam yeeb lossis aerosol tiv thaiv lub dav hlau. Vim yog lub nrawm ntawm lub dav hlau, pa luam yeeb lossis aerosol ib txwm yuav tshuab rov qab los ntawm huab cua tuaj, hauv cov dav hlau helicopters lawv yuav raug cua tshuab los ntawm cov cua los ntawm cov kiv cua.
Yog li, kev tiv thaiv tiv thaiv riam phom laser nyob rau hauv daim ntawv ntawm cov pa tsuag thiab aerosols yuav xav tau tsuas yog ntawm cov tsheb me me. Ntawm qhov tod tes, tso tsheb hlau luam thiab lwm lub tsheb tiv thaiv tub rog feem ntau twb tau nruab nrog cov txheej txheem teeb tsa cov ntxaij vab tshaus txhawm rau cuam tshuam kev ntes cov yeeb ncuab riam phom tshuab, thiab hauv qhov no, thaum tsim cov khoom tsim nyog, lawv kuj tuaj yeem siv los tiv thaiv riam phom laser..
Rov qab los rau kev tiv thaiv cov cuab yeej siv kho qhov muag thiab cua sov, nws tuaj yeem xav tias kev teeb tsa cov lim dej uas tiv thaiv kev nkag mus ntawm cov kab hluav taws xob laser ntawm qee qhov nthwv dej yuav tsim nyog tsuas yog nyob rau theem pib rau kev tiv thaiv tiv thaiv lub zog hluav taws xob laser tsawg, rau cov laj thawj hauv qab no:
- hauv kev pabcuam yuav yog qhov loj ntawm cov lasers los ntawm cov tuam txhab sib txawv ua haujlwm ntawm cov nthwv dej sib txawv;
- lub lim dej tsim los nqus lossis cuam tshuam txog qee qhov nthwv dej, thaum raug rau cov hluav taws xob muaj zog, zoo li yuav ua tsis tiav, uas yuav ua rau lub tshuab hluav taws xob laser tsoo lub ntsej muag rhiab, lossis tsis ua haujlwm ntawm qhov muag nws tus kheej (clouding, duab tsis zoo);
- qee lub tshuab lasers, tshwj xeeb yog lub tshuab siv hluav taws xob dawb, tuaj yeem hloov pauv kev ua haujlwm nthwv dej hla ntau yam.
Kev tiv thaiv cov cuab yeej siv kho qhov muag thiab cua sov tuaj yeem nqa tawm rau cov khoom siv hauv av, nkoj thiab khoom siv dav hlau, los ntawm kev txhim kho cov ntxaij vab tshaus tiv thaiv siab. Yog tias pom hluav taws xob hluav taws xob, lub vijtsam tiv thaiv yuav tsum npog cov iav hauv ib feem ntawm ib pliag, tab sis txawm tias qhov no tsis tuaj yeem lav qhov tsis muaj kev puas tsuaj rau cov khoom rhiab. Nws muaj peev xwm hais tias kev siv cov riam phom laser thoob plaws lub sijhawm yuav xav tau yam tsawg kawg ntawm kev rov ua dua ntawm cov cuab yeej tshawb nrhiav uas ua haujlwm hauv qhov kho qhov muag ntau.
Yog tias ntawm cov neeg nqa khoom loj kev teeb tsa cov ntxaij vab tshaus tiv thaiv thiab sib piv txhais tau tias ntawm kev saib xyuas qhov muag thiab cua sov yog qhov ua tau zoo, tom qab ntawd siv riam phom muaj tseeb, tshwj xeeb tshaj yog cov me me, qhov no nyuaj dua. Ua ntej, qhov hnyav thiab qhov xav tau me me rau kev tiv thaiv yog nruj me ntsis, thiab qhov thib ob, qhov cuam tshuam ntawm lub zog hluav taws xob hluav taws xob siab txawm tias kaw lub qhov rooj tuaj yeem ua rau lub cev sov dhau ntawm cov khoom siv ntawm qhov kho qhov muag vim qhov teeb tsa tuab, uas yuav ua rau ib nrab lossis ua tiav kev cuam tshuam ntawm nws txoj haujlwm.
Cov txheej txheem twg tuaj yeem siv los tiv thaiv cov cuab yeej thiab riam phom zoo los ntawm riam phom laser? Muaj ob txoj hauv kev tseem ceeb - tiv thaiv ablative thiab tiv thaiv kev tiv thaiv tshav kub.
Kev tiv thaiv ablation (los ntawm Latin ablatio - tshem tawm, nqa tawm ntawm qhov hnyav) yog raws li kev tshem tawm cov tshuaj los ntawm qhov chaw ntawm cov khoom tiv thaiv los ntawm cov kwj dej kub thiab / lossis ntawm kev kho dua tshiab ntawm cov ciam txheej txheej, uas ua ke tseem ceeb txo cov cua sov hloov mus rau qhov chaw tiv thaiv. Hauv lwm lo lus, lub zog tuaj yog siv cua sov, yaj, thiab ua kom qhuav ntawm cov khoom tiv thaiv.
Tam sim no, kev tiv thaiv ablative tau nquag siv hauv qhov nqis qis ntawm cov chaw dav hlau (SC) thiab hauv lub dav hlau cav lub taub hau. Kev siv ntau tshaj plaws yog cov yas uas siv tau raws li phenolic, organosilicon thiab lwm cov khoom siv hluavtaws uas muaj cov pa roj carbon (suav nrog graphite), silicon dioxide (silica, quartz), thiab nylon ua cov ntim khoom.
Kev tiv thaiv ablation yog pov tseg, hnyav thiab hnyav, yog li nws tsis muaj kev nkag siab siv nws ntawm lub dav hlau rov siv tau (nyeem tsis yog txhua tus neeg, thiab feem ntau tsis siv neeg lub dav hlau). Nws tsuas yog daim ntawv thov yog ntawm cov lus qhia thiab tsis siv qhov projectiles. Thiab ntawm no cov lus nug tseem ceeb yog tuab npaum li cas yuav tsum yog kev tiv thaiv rau lub laser nrog lub zog, piv txwv li, 100 kW, 300 kW, thiab lwm yam.
Ntawm lub dav hlau Apollo, qhov tuab ntawm qhov thaiv ntawm 8 txog 44 hli rau qhov kub thiab txias los ntawm ntau pua mus rau ntau txhiab degrees. Ib qhov twg ntawm qhov no, qhov xav tau tuab ntawm ablative tiv thaiv los ntawm kev sib ntaus lasers tseem yuav dag. Nws yog qhov yooj yim los xav txog yuav ua li cas nws yuav cuam tshuam rau qhov hnyav thiab cov yam ntxwv loj, thiab, yog li ntawd, thaj tsam, kev tswj hwm lub cev, lub taub hau hnyav thiab lwm yam kev txwv ntawm cov mos txwv. Kev tiv thaiv tshav kub yuav tsum tiv taus qhov hnyav tshaj thaum lub sijhawm tsim tawm thiab tswj hwm, ua raws li cov cai ntawm cov lus thiab cov xwm txheej ntawm kev ntim cov mos txwv.
Cov mos txwv uas tsis siv yog cov lus nug, vim tias kev puas tsuaj tsis sib xws ntawm kev tiv thaiv ablative los ntawm cov hluav taws xob laser tuaj yeem hloov pauv sab nrauv, vim qhov uas cov mos txwv sib txawv ntawm lub hom phiaj. Yog tias kev tiv thaiv ablative twb tau siv rau qee qhov, piv txwv li, hauv rab phom hypersonic, tom qab ntawd koj yuav tsum nce nws cov tuab.
Lwm txoj hauv kev tiv thaiv yog txheej txheej txheej lossis ua tiav ntawm rooj plaub nrog ob peb txheej tiv thaiv ntawm cov khoom siv hluav taws xob uas tiv taus rau sab nraud.
Yog tias peb kos qhov sib piv nrog lub dav hlau, tom qab ntawd peb tuaj yeem txiav txim siab qhov kev tiv thaiv cua sov ntawm lub dav hlau rov siv tau "Buran". Hauv thaj chaw uas qhov kub ntawm qhov kub yog 371 - 1260 degrees Celsius, txheej txheej tau ua los ntawm amorphous quartz fiber 99.7% purity, uas tau muab cov ntawv nplaum, colloidal silicon dioxide ntxiv. Cov npog tau ua hauv daim ntawv ntawm cov vuas ntawm ob tus qauv loj nrog tuab ntawm 5 txog 64 hli.
Borosilicate iav uas muaj cov xim tshwj xeeb (txheej xim dawb raws li silicon oxide thiab ci alumina) tau siv rau sab nrauv ntawm cov vuas kom thiaj li tau txais qhov nqus qis coefficient ntawm hnub ci tawg thiab muaj emissivity siab. Kev tiv thaiv ablation tau siv ntawm lub khob qhov ntswg thiab cov lus qhia tis ntawm lub tsheb, qhov kub tshaj 1260 degrees.
Nws yuav tsum nco ntsoov tias nrog kev ua haujlwm txuas ntxiv, kev tiv thaiv ntawm cov vuas los ntawm cov dej noo tuaj yeem cuam tshuam, uas yuav ua rau poob kev tiv thaiv cua sov ntawm nws cov khoom, yog li nws tsis tuaj yeem siv ncaj qha los tiv thaiv kev tiv thaiv laser ntawm lub dav hlau siv tau.
Lub sijhawm tam sim no, kev cog lus tiv thaiv kev tiv thaiv cua sov nrog qhov tsawg tshaj plaws hnav tau raug tsim, uas ua kom muaj kev tiv thaiv dav hlau los ntawm qhov kub txog 3000 degrees.
Pab pawg kws tshawb fawb los ntawm Royce Institute ntawm University of Manchester (UK) thiab Central South University (Tuam Tshoj) tau tsim cov khoom tshiab nrog cov yam ntxwv zoo uas tuaj yeem tiv taus kub txog 3000 ° C yam tsis muaj kev hloov pauv. Qhov no yog txheej txheej ceramic Zr0.8Ti0.2C0.74B0.26, uas tau muab tso rau ntawm cov pa roj carbon-carbon sib xyaw ua ke. Hais txog nws cov yam ntxwv, txheej txheej tshiab ua tau zoo tshaj qhov ua tau zoo tshaj kub kub.
Cov qauv tshuaj lom neeg ntawm cov cua kub-resistant ceramics nws tus kheej ua raws li kev tiv thaiv txheej txheem. Ntawm qhov kub ntawm 2000 ° C, cov ntaub ntawv Zr0.8Ti0.2C0.74B0.26 thiab SiC oxidize thiab hloov pauv mus rau Zr0.80T0.20O2, B2O3, thiab SiO2, feem. Zr0.80Ti0.20O2 ib nrab yaj thiab tsim cov txheej tuab tuab, thaum qis-melting oxides SiO2 thiab B2O3 evaporate. Ntawm qhov kub siab dua ntawm 2500 ° C, Zr0.80Ti0.20O2 muaju tau sib xyaw ua ke kom loj dua. Ntawm qhov kub ntawm 3000 ° C, yuav luag txheej tuab tuab tuab tau tsim, feem ntau yog Zr0.80Ti0.20O2, zirconium titanate thiab SiO2.
Lub ntiaj teb tseem tab tom tsim cov txheej tshwj xeeb uas tsim los tiv thaiv hluav taws xob laser.
Rov qab rau xyoo 2014, tus kws tshaj lij rau Pab Tib Neeg Liberation Army ntawm Tuam Tshoj tau hais tias Asmeskas cov lasers tsis ua rau muaj kev phom sij tshwj xeeb rau Suav cov cuab yeej siv tub rog uas muaj txheej tiv thaiv tshwj xeeb. Tsuas yog cov lus nug uas tseem nyob yog lub lasers ntawm lub zog twg txheej txheej no tiv thaiv, thiab tuab npaum li cas thiab qhov hnyav nws muaj.
Qhov txaus siab tshaj plaws yog txheej txheej tsim los ntawm Asmeskas cov kws tshawb fawb los ntawm National Institute of Standards and Technology thiab University of Kansas - cov tshuaj aerosol raws li kev sib xyaw ntawm cov pa nanotubes thiab cov khoom siv tshwj xeeb, muaj peev xwm ua tau zoo nqus tau lub teeb ci. Lub nanotubes ntawm cov khoom siv tshiab sib xws nqus lub teeb thiab hloov cua sov mus rau thaj chaw nyob ze, txo qhov kub ntawm qhov chaw ntawm kev sib cuag nrog lub teeb ci laser. Cov pob zeb kub-kub sib xyaw ua ke muab cov txheej txheej tiv thaiv nrog cov cuab yeej muaj zog thiab tiv taus kev puas tsuaj los ntawm qhov kub siab.
Thaum kuaj, ib txheej txheej ntawm cov khoom siv tau siv rau saum npoo tooj liab thiab, tom qab ziab, tsom mus rau saum npoo ntawm cov khoom siv nqaj ntawm lub tshuab hluav taws xob nthwv dej ntev ntev, laser siv los txiav cov hlau thiab lwm yam khoom siv tawv.
Kev tshuaj xyuas ntawm cov ntaub ntawv sau qhia pom tias txheej txheej nqus tau zoo 97.5 feem pua ntawm lub zog hluav taws xob laser thiab tiv thaiv lub zog ntawm 15 kW ib square centimeter ntawm qhov chaw tsis muaj kev puas tsuaj.
Ntawm cov txheej no, cov lus nug tshwm sim: hauv kev sim, txheej tiv thaiv tau siv rau tooj liab saum npoo, uas nyob hauv nws tus kheej yog ib qho ntawm cov ntaub ntawv nyuaj tshaj plaws rau kev ua laser, vim nws cov cua sov ua kom sov siab, nws tsis paub meej tias yuav tiv thaiv txheej li cas yuav coj nrog lwm cov ntaub ntawv. Tsis tas li, cov lus nug tshwm sim txog nws qhov kub tshaj plaws tiv taus, tiv taus kev vibration thiab poob siab, cuam tshuam ntawm huab cua puag thiab hluav taws xob ultraviolet (hnub). Lub sijhawm nyob rau lub sijhawm uas tau muab cov tshuaj tua hluav taws tawm tsis tau qhia.
Lwm qhov ntsiab lus nthuav: yog tias lub tshuab dav hlau tseem muaj txheej nrog cov khoom uas muaj cov cua sov zoo, tom qab ntawd tag nrho lub cev yuav sov ib yam los ntawm lawv, uas feem ntau nthuav tawm lub dav hlau hauv cov cua sov.
Hauv txhua qhov xwm txheej, cov yam ntxwv ntawm kev tiv thaiv aerosol saum toj no yuav ncaj qha rau qhov loj ntawm cov khoom tiv thaiv. Qhov loj dua qhov khoom tiv thaiv thiab thaj chaw npog, lub zog ntau tuaj yeem tawg thoob plaws thaj chaw thiab muab rau hauv daim ntawv ntawm tshav kub thiab cua txias los ntawm qhov xwm txheej huab cua ntws. Cov khoom tiv thaiv me dua, cov tuab tuab yuav tsum muaj kev tiv thaiv. thaj chaw me me yuav tsis tso cua sov txaus kom tshem tawm thiab cov txheej txheem sab hauv yuav ua kom sov dhau.
Kev siv kev tiv thaiv tiv thaiv hluav taws xob hluav taws xob, tsis muaj teeb meem ablative lossis ua kom sov-insulating, tuaj yeem thim rov qab qhov kev hloov pauv mus rau qhov loj me ntawm cov riam phom coj los, txo qhov ua tau zoo ntawm ob qho kev qhia thiab tsis yog coj ua.
Txhua qhov chaw ntawm cov kabmob thiab kev tswj hwm - tis, ruaj khov, rudders - yuav tsum tau ua los ntawm kim thiab nyuaj rau txheej txheem cov khoom siv hluav taws xob.
Ib lo lus nug sib cais tshwm sim ntawm kev tiv thaiv cov cuab yeej ntsuas radar. Ntawm qhov kev sim dav hlau "BOR-5", lub xov tooj cua-pob tshab tshav kub tiv thaiv tau sim-fiberglass nrog cov silica muab tub lim, tab sis kuv tsis tuaj yeem pom nws qhov kev tiv thaiv tshav kub thiab qhov hnyav thiab cov yam ntxwv loj.
Nws tseem tsis tau paub meej tias kev tsim cov ntshav kub tuaj yeem tshwm sim los ntawm kev ua hluav taws xob nrog lub zog hluav taws xob hluav taws xob los ntawm lub radome ntawm cov cuab yeej ntsuas radar, txawm hais tias muaj kev tiv thaiv los ntawm cov hluav taws xob cua sov, uas tiv thaiv kev hla ntawm xov tooj cua tsis, vim yog uas lub hom phiaj tuaj yeem ploj.
Txhawm rau tiv thaiv rooj plaub, kev siv ua ke ntawm ob peb txheej tiv thaiv tuaj yeem siv tau-tiv tshav kub-tiv taus-kub-ua kom zoo los ntawm sab hauv thiab cuam tshuam-tshav kub-tiv taus-muaj cua sov-coj los ntawm sab nraud. Nws tseem muaj peev xwm hais tias cov ntaub ntawv zais cia yuav raug siv rau sab saum toj ntawm kev tiv thaiv tiv thaiv hluav taws xob laser, uas yuav tsis tuaj yeem tiv taus hluav taws xob laser, thiab yuav tsum tau rov zoo los ntawm kev puas tsuaj los ntawm riam phom laser thaum lub dav hlau nws tus kheej muaj txoj sia nyob.
Nws tuaj yeem xav tias kev txhim kho thiab nthuav dav faib cov riam phom laser yuav xav tau kev tiv thaiv kev tiv thaiv laser rau txhua qhov muaj mos txwv, ob qho tib si coj thiab tsis siv, nrog rau cov neeg tsav tsheb thiab tsis muaj lub dav hlau.
Kev taw qhia txog kev tiv thaiv kev tiv thaiv laser yuav ua tsis tiav ua rau nce nqi thiab qhov hnyav thiab qhov ntev ntawm kev coj thiab tsis siv lub foob pob, nrog rau cov neeg tsav tsheb thiab tsis muaj neeg tsav tsheb.
Hauv kev xaus, peb tuaj yeem hais txog ib qho ntawm txoj hauv kev tsim los tiv thaiv kev tawm tsam laser. California-based Adsys Controls tab tom txhim kho Helios cov txheej txheem tiv thaiv, uas yog xav kom thim cov yeeb ncuab qhia laser.
Thaum tsom rau tus yeeb ncuab kev sib ntaus sib tua laser ntawm lub cuab yeej tiv thaiv, Helios txiav txim siab nws qhov tsis: lub zog, nthwv dej, mem tes zaus, kev taw qhia thiab nrug deb rau qhov chaw. Helios ntxiv tiv thaiv tus yeeb ncuab lub teeb nrig laser los ntawm kev tsom mus rau lub hom phiaj, suav tias yog los ntawm kev tsom mus rau lub zog qis zog laser nqaj, uas ua rau cov yeeb ncuab lub hom phiaj phiaj. Cov yam ntxwv ntxaws ntawm Helios system, theem ntawm nws txoj kev txhim kho thiab nws qhov kev ua tau zoo tseem tsis tau paub.
