Tham txog cov hniav nyob rau hauv tib neeg feem ntau yog txuam nrog caries, braces thiab sadists nyob rau hauv lub tsho loj dawb uas tsuas yog npau suav ntawm ua hlaws tawm ntawm koj cov hniav. Tab sis kev tso dag tso tseg, vim tias tsis muaj kws kho hniav thiab tsim cov kev cai huv ntawm qhov ncauj, peb tsuas yog noj cov qos yaj ywm thiab kua zaub los ntawm cov quav cab. Thiab txhua yam yog los liam rau evolution, uas tau muab rau peb nyob deb ntawm cov feem ntau ruaj cov hniav, uas tseem tsis regenerate, uas tej zaum indescribably pleases cov neeg sawv cev ntawm kev kho hniav kev lag luam. Yog hais tias peb tham txog cov hniav ntawm cov neeg sawv cev ntawm cov tsiaj qus, ces majestic tsov ntxhuav, bloodthirsty sharks thiab heev zoo hyenas tam sim ntawd los rau hauv lub siab. Txawm li cas los xij, txawm tias lub zog thiab lub zog ntawm lawv lub puab tsaig, lawv cov hniav tsis zoo li cov hiav txwv urchins. Yog lawm, lub pob ntawm koob hauv qab dej, uas koj tuaj yeem rhuav tshem qhov zoo ntawm koj so, muaj cov hniav zoo heev. Ntawm cov hoob kawm, tsis muaj ntau ntawm lawv, tsuas yog tsib, tab sis lawv yog tshwj xeeb nyob rau hauv lawv tus kheej txoj kev thiab muaj peev xwm ntse ntse lawv tus kheej. Cov kws tshawb fawb tau txheeb xyuas qhov zoo li no li cas, cov txheej txheem no tau ua li cas thiab nws yuav pab tau tib neeg li cas? Peb kawm txog qhov no los ntawm tsab ntawv ceeb toom ntawm pawg tshawb fawb. Mus.
Kev tshawb fawb hauv paus
Ua ntej ntawm tag nrho cov, nws yog tsim nyog los paub lub ntsiab ntawm txoj kev tshawb no - Strongylocentrotus fragilis, nyob rau hauv tib neeg cov nqe lus, nrog ib tug liab hiav txwv urchin. Hom hiav txwv urchin no tsis txawv heev los ntawm nws cov lwm yam sib txawv, tshwj xeeb tshaj yog cov duab flattened ntawm tus ncej thiab xim glamorous. Lawv nyob tob heev (los ntawm 100 m mus rau 1 km), thiab lawv loj hlob mus txog 10 cm inch.
Lub "skeleton" ntawm lub hiav txwv urchin, uas qhia tau hais tias tsib-ray symmetry.
Hiav txwv urchins yog, txawm li cas los rude nws yuav suab, yog thiab tsis ncaj ncees lawm. Lub qub muaj ib tug yuav luag zoo kawg nkaus puag ncig lub cev nrog pronounced tsib-beam symmetry, thaum lub tom kawg yog ntau asymmetric.
Thawj qhov uas ntes koj lub qhov muag thaum koj pom hiav txwv urchin yog nws cov quills uas npog tag nrho lub cev. Hauv ntau hom, cov koob tuaj yeem yog los ntawm 2 hli mus txog 30 cm. Ntxiv nrog rau cov koob, lub cev muaj spheridia (lub cev sib npaug) thiab pedicellaria (cov txheej txheem uas zoo li forceps).
Tag nrho tsib hniav yog pom meej nyob rau hauv qhov chaw.
Txhawm rau piav qhia txog lub hiav txwv urchin, koj yuav tsum xub sawv ntsug, vim tias nws lub qhov ncauj qhib nyob rau sab qis ntawm lub cev, tab sis lwm qhov yog nyob rau sab sauv. Lub qhov ncauj ntawm hiav txwv urchins tau nruab nrog lub tshuab zom zom nrog lub npe zoo nkauj "Aristotle's lantern" (nws yog Aristotle uas thawj zaug piav txog lub cev no thiab muab piv rau hauv cov duab nrog lub teeb txawb qub). Lub cev no tau nruab nrog tsib lub puab tsaig, txhua qhov xaus rau hauv cov hniav ntse (lub teeb Aristotelian ntawm cov duab liab hedgehog tau pom hauv daim duab 1C hauv qab no).
Muaj ib qho kev xav tias lub durability ntawm cov hniav ntawm hiav txwv urchins yog guaranteed los ntawm lawv tas li sharpening, uas tshwm sim los ntawm gradual puas tsuaj ntawm cov mineralized hniav daim hlau los tuav lub sharpness ntawm lub distal nto.
Tab sis yuav ua li cas raws nraim txoj kev no mus, uas cov hniav yuav tsum tau sharpened thiab uas tsis, thiab yuav ua li cas yog qhov tseem ceeb qhov kev txiav txim? Cov kws tshawb fawb tau sim nrhiav cov lus teb rau cov lus nug no.
Cov txiaj ntsig tshawb fawb
Duab #1
Ua ntej nthuav tawm cov hniav zais ntawm hiav txwv urchins, xav txog cov qauv ntawm lawv cov hniav feem ntau.
Ntawm cov duab 1A-1S hero ntawm txoj kev tshawb no qhia - ib tug liab hiav txwv urchin. Zoo li lwm cov hiav txwv urchins, cov neeg sawv cev ntawm hom no tau txais lawv cov ntxhia hauv dej hiav txwv. Ntawm cov pob txha pob txha, cov hniav yog cov mineralized heev (los ntawm 99%) nrog magnesium-enriched calcite.
Raws li peb tau tham ua ntej, hedgehogs siv lawv cov hniav rau scraping zaub mov. Tab sis tsis tas li ntawd, nrog kev pab los ntawm lawv cov hniav, lawv khawb qhov rau lawv tus kheej, nyob rau hauv uas lawv nkaum los ntawm predators los yog huab cua phem. Muab qhov txawv txav no siv cov hniav, tom kawg yuav tsum muaj zog heev thiab ntse.
Ntawm daim duab 1D microcomputed tomography ntawm ib ntu ntawm tag nrho cov hniav yog qhia, ua kom pom tseeb tias cov hniav yog tsim raws ib tug elliptical nkhaus nrog ib tug T-shaped cross seem.
Hla ntu ntawm tus hniav (1E) qhia tau hais tias cov hniav yog tsim los ntawm peb cheeb tsam cov qauv: thawj laminae, calculus cheeb tsam, thiab theem nrab lamellae. Lub pob zeb cheeb tsam muaj fibers ntawm me me txoj kab uas hla, surrounded los ntawm cov organic plhaub. Cov fibers yog encased nyob rau hauv ib tug polycrystalline matrix muaj li ntawm magnesium-nplua nuj calcite hais. Txoj kab uas hla ntawm cov khoom no yog hais txog 10-20 nm. Cov kws tshawb fawb tau sau tseg tias cov ntsiab lus ntawm magnesium tsis zoo ib yam thoob plaws hauv cov hniav thiab nce ze rau nws qhov kawg, uas muab nws cov hnav tsis kam thiab hardness.
Longitudinal seem (1F) ntawm cov calculus ntawm cov hniav qhia txog kev puas tsuaj ntawm cov fibers, nrog rau kev sib cais, uas tshwm sim vim delamination ntawm lub interface ntawm cov fibers thiab cov organic plhaub.
Thawj veneers feem ntau yog tsim los ntawm calcite ib leeg muaju thiab nyob rau ntawm qhov chaw ntawm cov hniav, thaum cov veneers theem nrab sau cov concave nto.
Daim duab 1G ib tug yuav pom ib tug array ntawm nkhaus thawj daim hlau dag thaum uas tig mus rau ib leeg. Daim duab kuj qhia tau tias fibers thiab polycrystalline matrix sau qhov chaw ntawm daim hlau. keel (1H) tsim lub hauv paus ntawm transverse T-section thiab tsub kom qhov bending txhav ntawm cov hniav.
Txij li thaum peb paub tias tus hniav ntawm lub hiav txwv liab urchin muaj dab tsi, tam sim no peb yuav tsum nrhiav kom paub cov khoom ntawm nws cov khoom. Rau qhov no, kev ntsuas compression tau ua tiav siv lub tshuab ntsuas hluav taws xob thiab cov qauv nanoindentation *. Cov qauv txiav raws lub longitudinal thiab transverse orientations ntawm tus hniav koom nrog nanomechanical xeem.
Nanoindentation * - xyuas cov khoom siv los ntawm txoj kev indentation rau saum npoo ntawm cov qauv ntawm cov cuab yeej tshwj xeeb - lub indenter.
Cov ntaub ntawv tsom xam pom tias qhov nruab nrab ntawm Young's modulus (E) thiab hardness (H) ntawm cov hniav hauv qhov ntev thiab cov lus qhia transverse yog: EL = 77.3 Β± 4,8 GPa, HL = 4.3 Β± 0.5 GPa (longitudinal) thiab ET = 70.2 Β± 7.2 GPa, HT = 3,8 Β± 0,6 GPa (transverse).
Young's modulus* - lub cev kom muaj nuj nqis uas piav qhia txog lub peev xwm ntawm cov khoom siv los tiv thaiv kev nro thiab compression.
Hardness * - cov cuab yeej ntawm cov khoom siv los tiv thaiv kev taw qhia ntawm lub cev muaj zog (indenter).
Tsis tas li ntawd, recesses tau ua nyob rau hauv lub longitudinal kev taw qhia nrog ib tug cyclic ntxiv load los tsim ib tug qauv ntawm ductile puas tsuaj rau lub pob zeb cheeb tsam. Ntawm 2A qhia tau hais tias load-displacement nkhaus.
Duab #2
Lub modulus rau txhua lub voj voog yog xam raws li Oliver-Farr txoj kev siv unloading cov ntaub ntawv. Cov voj voog indentation tau pom qhov txo qis hauv monotonic hauv cov qauv nrog nce qhov tob tob (2B). Xws li ib tug deterioration nyob rau hauv nruj yog piav los ntawm tsub zuj zuj ntawm kev puas tsuaj (2C) raws li qhov tshwm sim ntawm irreversible deformation. Nws yog noteworthy tias txoj kev loj hlob ntawm peb tshwm sim nyob ib ncig ntawm lub fibers, thiab tsis yog los ntawm lawv.
Cov cuab yeej cuab tam ntawm cov hniav cov ntsiab lus kuj tau soj ntsuam siv quasi-static micropillar compression thwmsim. Lub teeb tsom ion beam tau siv los tsim cov ncej micrometer. Txhawm rau ntsuam xyuas lub zog ntawm kev sib txuas ntawm cov phiaj tseem ceeb ntawm sab convex ntawm cov hniav, micropillars tau fabricated nrog oblique orientation txheeb ze rau qhov zoo sib xws ntawm cov phaj (2D). Daim duab 2E pom ib microcolumn nrog inclined interface. Thiab ntawm daim duab 2F Cov txiaj ntsig ntawm kev ntsuas kev ntxhov siab yog qhia.
Cov kws tshawb fawb sau tseg qhov tseeb nthuav - qhov ntsuas ntsuas ntawm elasticity yog yuav luag ib nrab ntawm cov kev ntsuas indentation. Qhov tsis sib xws ntawm qhov ntsuas qhov ntsuas thiab qhov ntsuas compression kuj tau sau tseg rau cov hniav enamel. Lub sijhawm tam sim no, muaj ntau qhov kev xav piav qhia qhov tsis sib xws (los ntawm ib puag ncig cuam tshuam thaum lub sijhawm kuaj mus rau kev sib kis ntawm cov qauv), tab sis tsis muaj lus teb meej rau cov lus nug vim li cas qhov sib txawv tshwm sim.
Cov kauj ruam tom ntej ntawm txoj kev tshawb fawb ntawm cov hniav ntawm hiav txwv urchin yog hnav cov kev ntsuam xyuas siv lub tshuab ntsuas hluav taws xob scanning. Cov hniav yog glued mus rau ib tug tshwj xeeb tuav thiab nias tiv thaiv ib tug substrate ntawm ultrananocrystalline pob zeb diamond (3A).
Duab #3
Cov kws tshawb fawb tau sau tseg tias lawv cov qauv ntawm kev sim hnav yog qhov sib txawv ntawm qhov feem ntau ua tiav thaum lub pob zeb diamond taub yog nias rau hauv lub substrate ntawm cov khoom hauv kev kawm. Cov kev hloov pauv hauv cov txheej txheem kev hnav khaub ncaws tso cai rau kev nkag siab zoo ntawm cov khoom ntawm microstructures thiab cov hniav.
Raws li peb tuaj yeem pom hauv cov duab, thaum qhov tseem ceeb thauj khoom mus txog, chips pib tsim. Nws yog tsim nyog xav tias lub zog ntawm "tom" ntawm Aristotelian teeb nyob rau hauv hiav txwv urchins txawv nyob ntawm seb hom ntawm 1 mus rau 50 newtons. Hauv kev sim, ib qho quab yuam los ntawm ntau pua micronewtons rau 1 newton tau siv, piv txwv li. los ntawm 1 mus rau 5 newtons rau tag nrho Aristotelian teeb (vim muaj tsib hniav).
Daim duab 3B (i) me me (xub xub liab) yog pom, tsim los ntawm kev hnav ntawm lub pob zeb cheeb tsam. Raws li thaj chaw pob zeb hnav thiab sib cog lus, cov kab nrib pleb ntawm qhov sib cuam tshuam ntawm daim hlau tuaj yeem tshwm sim thiab nthuav tawm vim yog compression-shear loading thiab kev ntxhov siab nyob rau hauv thaj tsam ntawm cov calcite daim hlau. Snapshots 3B(ii) ΠΈ 3B(iii) qhia cov chaw uas cov fragments tawg tawm.
Rau kev sib piv, ob hom kev sim hnav tau ua tiav: nrog kev thauj khoom tas li sib haum mus rau qhov pib ntawm kev tawm los (WCL) thiab nrog kev thauj khoom tas li sib raug rau lub zog tawm los (WCS). Raws li qhov tshwm sim, ob qhov sib txawv ntawm cov hniav hnav tau txais.
Wear test video:
Theem I
Theem II
Theem III
Theem IV
Nyob rau hauv cov ntaub ntawv ntawm ib tug tas li load nyob rau hauv lub WCL xeem, compression ntawm cheeb tsam tau pom, txawm li cas los xij, tsis muaj chipping lossis lwm yam kev puas tsuaj rau daim hlau (4A). Tab sis nyob rau hauv qhov kev xeem WCS, thaum lub zog ib txwm tau nce los tswj qhov nominal tiv tauj voltage tas li, chipping thiab ntog tawm ntawm daim hlau raug pom (4B).
Duab #4
Cov kev soj ntsuam no tau lees paub los ntawm cov phiaj xwm (4S) kev ntsuas ntawm thaj tsam compression thiab qhov ntim ntawm daim hlau chipped nyob ntawm qhov ntev zawv zawg (piv txwv li pob zeb diamond thaum kuaj).
Daim duab no tseem qhia tau hais tias nyob rau hauv rooj plaub ntawm WCL tsis muaj chips raug tsim txawm tias qhov zawv zawg qhov deb ntau dua li ntawm WCS. Kev tshuaj xyuas ntawm compressed thiab chipped daim hlau rau 4B tso cai rau koj kom nkag siab zoo dua cov txheej txheem ntawm tus kheej-sharpening ntawm hiav txwv urchin hniav.
Qhov chaw ntawm qhov chaw compressed ntawm lub pob zeb nce ntxiv thaum lub phaj tawg, ua rau ib feem ntawm qhov chaw compressed raug tshem tawm. [4B(iii-v)]. Microstructural nta xws li daim ntawv cog lus ntawm pob zeb thiab slabs pab txoj kev no. Microscopy tau pom tias cov fibers hauv lub laij lej yog khoov thiab nkag mus rau hauv cov txheej txheem ntawm cov phaj hauv qhov convex ntawm cov hniav.
Ntawm daim duab 4S muaj qhov dhia hauv qhov ntim ntawm qhov chaw chipped thaum lub phaj tshiab tau muab tshem tawm ntawm cov hniav. Nws yog xav paub tias nyob rau tib lub sijhawm muaj qhov txo qis hauv qhov dav ntawm thaj av oblate (4D), uas qhia tau hais tias tus txheej txheem ntawm tus kheej ntse.
Yooj yim muab tso, cov kev sim no tau pom tias thaum tuav lub cev tsis tu ncua (tsis yog qhov tseem ceeb) thaum lub sij hawm kuaj hnav, lub taub hau ua blunt, thaum cov hniav tseem ntse. Nws hloov tawm hais tias cov hniav ntawm hedgehogs yog sharpened thaum lub sij hawm siv, yog hais tias lub load tsis tshaj qhov tseem ceeb, txwv tsis pub kev puas tsuaj (chips) yuav tshwm sim, thiab tsis sharpening.
Duab #5
Yuav kom nkag siab txog lub luag haujlwm ntawm cov hniav microstructures, lawv cov khoom thiab lawv txoj kev koom tes rau tus kheej-sharpening mechanism, ib tug nonlinear finite caij tsom xam ntawm cov txheej txheem hnav tau ua (5A). Ua li no, dluab ntawm ib tug longitudinal seem ntawm lub ntsis ntawm cov hniav yog siv los ua lub hauv paus rau ib tug ob-seem qauv uas muaj xws li pob zeb, daim hlau, keel thiab interfaces ntawm daim hlau thiab pob zeb.
Dluab 5B-5H yog contour plots ntawm Mises criterion (plasticity criterion) ntawm ntug ntawm pob zeb thiab slab cheeb tsam. Thaum tus hniav yog compressed, lub calculus undergoes loj viscoplastic deformations, accumulates puas thiab shrinks ("flattens") (5B ΠΈ 5C). Ntxiv compression induces ib tug shear band nyob rau hauv lub pob zeb, qhov twg feem ntau ntawm cov yas deformation thiab kev puas tsuaj accumulates, tearing tawm ib feem ntawm lub pob zeb, coj nws mus rau hauv kev sib cuag ncaj qha nrog lub substrate (5D). Xws li fragmentation ntawm pob zeb nyob rau hauv cov qauv no sib raug rau kev soj ntsuam soj ntsuam (split fragments ntawm 3B (i)). Compression kuj ua rau delamination ntawm daim hlau raws li cov ntsiab lus interface tau raug sib xyaw ua ke uas ua rau decohesion (peeling). Raws li qhov chaw sib cuag tau nce, qhov kev sib tiv tauj nce ntxiv, ua rau kev pib thiab nthuav tawm ntawm qhov tawg ntawm qhov cuam tshuam (5B-5E). Kev poob ntawm adhesion ntawm daim hlau txhawb lub kink, uas ua rau lub phaj sab nraud disengage.
Scratching exacerbates cuam tshuam kev puas tsuaj uas ua rau lub phaj tshem tawm thaum lub phaj (s) raug kev sib cais (qhov twg cov kab nrib pleb sib txawv ntawm lub interface thiab nkag mus rau lub phaj, 5G). Raws li cov txheej txheem txuas ntxiv mus, cov seem ntawm cov phaj raug tshem tawm ntawm qhov kawg ntawm cov hniav (5H).
Nws yog qhov xav paub tias qhov kev sim ua tau zoo heev kwv yees tias chipping nyob rau hauv ob qho tib si pob zeb thiab phaj cheeb tsam, uas cov kws tshawb fawb twb tau pom thaum lub sij hawm soj ntsuam (3B ΠΈ 5I).
Rau cov ncauj lus kom ntxaws ntxiv nrog cov nuances ntawm txoj kev tshawb no, kuv xav kom saib ΠΈ rau nws.
Epilogue
Txoj hauj lwm no ib zaug tau lees paub tias evolution tsis txhawb tib neeg cov hniav. Tiag tiag, hauv lawv txoj kev tshawb fawb, cov kws tshawb fawb tau tshawb xyuas kom meej thiab piav qhia txog cov txheej txheem ntawm tus kheej-sharpening ntawm cov hniav ntawm hiav txwv urchins, uas yog raws li cov qauv txawv ntawm cov hniav thiab qhov tseeb ntawm nws. Cov daim hlau npog lub hedgehog hniav tev tawm nyob rau hauv ib tug tej yam load, uas tso cai rau koj kom cov hniav ntse. Tab sis qhov no tsis tau txhais hais tias hiav txwv urchins tuaj yeem tsoo pob zeb, vim tias thaum cov ntsuas qhov tseem ceeb tau mus txog, cov kab nrib pleb thiab daim tawv nqaij ntawm cov hniav. Nws hloov tawm hais tias lub hauv paus ntsiab lus "muaj hwj chim, tsis muaj lub siab xav tau" yeej yuav tsis muaj txiaj ntsig.
Ib tug yuav xav tias txoj kev kawm ntawm cov hniav ntawm cov neeg nyob rau hauv lub hiav txwv sib sib zog nqus tsis coj tej yam txiaj ntsim rau txiv neej, tsuas yog rau kev txaus siab ntawm insatiable tib neeg xav paub. Txawm li cas los xij, cov kev paub uas tau txais los ntawm txoj kev tshawb no tuaj yeem ua lub hauv paus rau kev tsim cov khoom siv tshiab uas yuav muaj cov khoom zoo ib yam li cov hniav ntawm hedgehogs - hnav tsis kam, nws tus kheej-ntse ntawm cov khoom siv yam tsis muaj kev pab sab nraud, thiab kav ntev.
Yuav ua li cas nws yuav, xwm tuav ntau secrets uas peb tseem tsis tau qhia. Lawv puas yuav pab tau? Tej zaum yog, tej zaum tsis yog. Tab sis qee zaum, txawm tias nyob rau hauv kev tshawb fawb nyuaj tshaj plaws, qee zaum nws tsis yog qhov chaw uas tseem ceeb, tab sis taug kev nws tus kheej.
Hnub Friday yav tsaus ntuj:
Cov hav zoov hauv qab dej ntawm cov algae loj yog qhov chaw sib sau ua ke rau hiav txwv urchins thiab lwm cov neeg nyob hauv dej hiav txwv txawv txawv. (BBC Ntiaj Teb, suab-dhau - David Attenborough).
Ua tsaug rau kev saib, nyob xav paub thiab muaj lub lis piam zoo rau txhua tus! π
Ua tsaug uas koj nyob nrog peb. Koj puas nyiam peb cov ntawv? Xav pom cov ntsiab lus nthuav ntxiv? Txhawb nqa peb los ntawm kev tso ib qho kev txiav txim lossis qhia rau cov phooj ywg, 30% luv nqi rau cov neeg siv Habr ntawm qhov tshwj xeeb analogue ntawm nkag-theem servers, uas tau tsim los ntawm peb rau koj: (muaj nrog RAID1 thiab RAID10, mus txog 24 cores thiab mus txog 40GB DDR4).
Dell R730xd 2 zaug pheej yig dua? Tsuas yog nyob ntawm no hauv Netherlands! Dell R420 - 2x E5-2430 2.2Ghz 6C 128GB DDR3 2x960GB SSD 1Gbps 100TB - los ntawm $ 99! Nyeem txog
Tau qhov twg los: www.hab.com