Tus txiv neej tau siv ntoo txij thaum immemorial. Roj, khoom siv hauv tsev, rooj tog zaum, cov twj paj nruag - cov khoom los ntawm nws nrog peb tag nrho peb lub neej. Tsis tas li ntawd, ntoo yog daim ntawv qhia hnub ntuj thiab muaj sia nyob keeb kwm monuments.
Nws muaj tag nrho cov ceg ntawm kev tshawb fawb - dendrochronology, uas tso cai rau koj los tshawb pom lub hnub nyoog ntawm cov khoom, nrog rau thaj tsam twg ntawm tsob ntoo uas nws tau txiav tawm. Kawm cov ntu ntawm cov nplhaib txhua xyoo, koj tuaj yeem kawm txog qhov xwm txheej thiab huab cua ntawm lub sijhawm qub. Qhov zoo thiab qhov tsis zoo, qauv, ntoo ua cov khoom siv hauv tsev, cov khoom siv - tag nrho cov teeb meem no tsim nyog mloog.
Yuav ua li cas ua haujlwm
Cov khoom thiab cov yam ntxwv ntawm cov khoom siv tsis tuaj yeem nkag siab yam tsis tau kawm thawj zaug thiab cov qauv ntawm cov ntoo. Lub tswvyim nws tus kheej nyob ntawm seb leej twg siv nws. Rau ib tus neeg zoo tib yam thiab cov neeg tsim khoom, qhov no tsuas yog ib feem ntawm tsob ntoo hauv qab tawv ntoo, uas tuaj yeem siv rau hauv lub neej txhua hnub lossis ntau lawm. Rau ib tug botanist, tus qauv ntawm tsob ntoo thiab ntoo yog tag nrho cov complex, nrog rau tag nrho cov ntsiab lus ntawm cov hauv paus hniav mus rau crown.
Krone yog siv hauv kev lag luamme ntsis, thiab cov ceg ntoo yog siv los ua raw khoom rau fiberboard thiab cardboard. Qhov tseem ceeb yog lub cev. Nyob rau ntawm tus ntoo khaub lig, tus qauv ntawm tsob ntoo pob tw opens. Cov txheej saum toj kawg nkaus, lub cortex, tiv thaiv cov cell nyob los ntawm kev cuam tshuam sab nraud. Nruab nrab ntawm cov tawv ntoo thiab lub cev ntawm lub cev yog ib txheej ntawm cov cell nyob - cadmium. Hauv qhov nruab nrab, cov tub ntxhais hla dhau tag nrho lub cev. Cov ntaub xoob uas nws tau tsim ua rau nws tsis haum rau kev siv siv.
Lub hauv paus ntawm tsob ntoo feem ntau yog cov cell tuag, resin deposits, dyes thiab tannins. Lub hauv paus yog surrounded los ntawm sapwood, ib feem ntawm tsob ntoo uas yog lub luag hauj lwm rau coj dej mus rau nplooj los ntawm cov hauv paus hniav. Yog li ntawd, nws muaj dej noo ntau, nws dhau dej ntau dua thiab nws yooj yim dua rau lwj. Tsis yog txhua tsob ntoo muaj lub ntsiab lus tseem ceeb. Hauv qee qhov ntawm lawv tsis muaj qhov sib txawv ntawm qhov nruab nrab thiab marginal ntawm lub cev. Cov pob zeb no hu ua sapwood.
Microscopic qauv ntawm ntoo
Siv lub tshuab tsom, koj tuaj yeem kawm cov qauv kom tob. Ntoo yog feem ntau tsim los ntawm cov hlwb tuag. Cov nroj tsuag hluas muaj lub plhaub thiab ib sab hauv - cytoplasm thiab nucleus. Lub hauv paus ntawm daim nyias nyias nyias yog cellulose lossis fiber. Sij hawm dhau mus, cov hlwb cog tau raug metamorphosis thiab, nyob ntawm qhov muaj nuj nqi ntawm lub cev, tig lawv qhov hnyav rau hauv cov tawv ntoo (corking) lossis ntoo (lignification).
Lignin tau tsim nyob rau hauv cov hlwb tas li. Nws yog vim li caslignification. Muaj ob hom ntoo hlwb - prosenchymal thiab parenchymal. Thawj hom ua rau cov ntoo ntau, nyob ntawm hom - los ntawm 85% mus rau 99%. Nyob rau hauv lem, lawv muab faib raws li lawv cov dej num. Conductive cells yog lub luag haujlwm rau kev xa cov as-ham thiab noo noo los ntawm cov hauv paus hniav mus rau nplooj, thaum lub tshuab hlwb yog lub luag haujlwm rau lub zog thiab ruaj khov ntawm tsob ntoo. Parenchymal hlwb ua raws li pantry rau cov nroj tsuag. Lawv khaws cov as-ham (rog, starches) thiab muab pov tseg raws li xav tau thaum lub sijhawm nyuaj.
Nyob ntawm hom ntoo, lawv cov qauv kuj txawv. Cov ntoo tau muab faib ua coniferous thiab deciduous. Cov qauv ntawm conifers yog yooj yim dua. Cov feem ntau yog tracheid hlwb. Cov yam ntxwv ntawm conifers muaj xws li muaj cov hlwb uas tsim cov resin. Nyob rau hauv ntau hom, lawv tuaj yeem sib cais los yog sib xyaw ua ke rau hauv cov kab ke ntawm cov kab ke.
Hardwood
Cov ntoo tawv ntoo thiab lawv cov qauv yog qhov nyuaj dua. Ntoo muaj cov hlab ntsha, libriform fibers thiab parenchymal hlwb. Txij li cov ntoo deciduous poob lawv cov nplooj nyob rau lub caij nplooj zeeg, lawv xav tau cov khoom noj loj hauv lub caij ntuj no. Yog li ntawd, ntau dua ntawm parenchymal hlwb lub luag hauj lwm rau tsub zuj zuj ntawm cov as-ham tshaj nyob rau hauv conifers. Qhov no tuaj yeem pom los ntawm cov ntsiab lus hais.
Properties
Ntoo muaj ntau yam khoom zoo. Cov yam ntxwv ntawm cov qauv yog vim li cas rau qhov no. Lub zog ntawm cov ntoo yog siab heev, thiab ntawm lub tsevcov ntaub ntawv ntawm qhov ntsuas no, nws occupies ib nrab txoj hauj lwm. Thiab muab lub ntiajteb txawj nqus me me, nws yog piv rau qhov kev hwm nrog cov hlau. Qhov tsis muaj zog ntawm cov ntoo yog tias nws yog cov khoom siv anisotropic. Lub peev xwm los tiv thaiv kev puas tsuaj yog nyob ntawm qhov kev taw qhia ntawm lub zog cuam tshuam rau qhov chaw ntawm cov fibers. Cov txiaj ntsig zoo tshaj plaws yog pom thaum cov khoom raug nthuav tawm raws cov fibers.
Lub rigidity ntawm ntoo me me, yog vim li cas rau qhov no yog cov qauv tshwj xeeb. Ntoo yog cov khoom ntxeem tau, hloov tau yooj yim. Beams muaj peev xwm rov qab tau lawv cov duab tom qab lub sijhawm luv luv. Tab sis residual deformations, vim lub sij hawm raug, nyob mus ib txhis. Lub nqaj ntoo yuav tsis tuaj yeem rov qab tau nws cov duab tom qab siv sijhawm ntev.
Lub hardness ntawm lub tsev cov ntaub ntawv yog txiav txim los ntawm lub load yog xav tau los nias lub pob steel nrog tej qhov ntev. Rau cov ntoo nyuaj tshaj plaws, nws tsuas yog 1000 N. Tib lub sijhawm, tsis tshua muaj hardness yog ib qho zoo ntawm cov khoom siv. Cov ntoo yog ib qho yooj yim rau txheej txheem, ntsia hlau, ntsia hlau, tus kheej tapping screws yog ruaj khov nyob rau hauv nws.
Cov dej noo ntawm cov ntoo yog txiav txim siab los ntawm cov dej noo tshwj xeeb hauv qhov pores. Nyob rau hauv ib tsob ntoo tshiab, nws ncav cuag 100%. Nyob ntawm lub hom phiaj, cov ntoo txiav tshiab tau qhuav rau qhov xav tau los ntawm 40 mus rau 15%.
Nyob zoo ib tsoom niam txiv kwv tij neej tsas sawv daws.
Ntoo muaj cov thermal conductivity tsawg. Nws tuaj yeem ua tiav siv los ua cov khoom siv hluav taws kub-insulating. Yooj yim ntawm kev uatso cai rau koj siv ntau yam cuab yeej. Nws yog tsis yooj yim sua xav txog tej yam orchestra yam tsis muaj suab paj nruag ua los ntawm ntoo. Lub suab nrov ntawm lub violin yog qhov tshwm sim ntawm xws li cov cuab yeej ntawm ntoo raws li lub peev xwm rau resonate. Cov ntoo tau yooj yim khoov, thiab muaj kev xaiv dav rau kev tsim khoom ntawm ntau cov qauv khoov. Tsis tas li ntawd, cov khoom ntoo muaj lub suab zoo-nqus cov yam ntxwv. Qhov chaw zoo nkauj qhib chav rau kev xav hauv kev tsim sab hauv.
Flaws
Lub peev xwm ntawm cov khoom ntoo kom thauj khoom yog nyob ntawm qhov kev taw qhia ntawm kev siv lub zog. Qhov no yog vim lub anisotropic qauv ntawm ntoo. Tsis tas li ntawd, cov yam ntxwv ntawm lub zog kuj yog nyob ntawm qhov sib thooj ntawm qhov nruab nrab ntawm lub cev, qhov av noo, muaj cov pob caus, tawg. Qhov no ua rau ntau lub sijhawm siv los xaiv cov khoom tsim nyog rau txoj haujlwm.
Ua cov khoom siv organic, ntoo tsis tiv thaiv kab, pwm thiab fungi. Rau kev ua haujlwm mus sij hawm ntev, kev kho tshuaj kim heev yog xav tau. Nws yog ib qho tsim nyog sau cia tias cov qauv ntoo uas tsis muaj kev kho mob ua ntej yog qhov yooj yim raug tua rau hluav taws.
Kev ua ntoo
Feem ntau, muaj peb hom kev ua ntoo:
- Feem ntau yog txoj kev siv tshuab. tsob ntoo yog sawn, npaj, faib.
- Thaum lub sij hawm tshuaj-mechanical ua, cov khoom raug rau nruab nrab kev npaj. Chips, shavings yog tov nrog ib tug binder thiab rhuab. Ib qho tshuaj tiv thaiv polymerization tshwm sim, thiab ntawm qhov tso zistau txais cov ntaub ntawv xws li plywood, chipboard, fiberboard.
- Thaum kho tshuaj, ntoo raug cov kua qaub, alkalis, ntsev, thiab raug tshav kub. Ntawm cov khoom lag luam ntawm kev ua haujlwm zoo li no, ib tus tuaj yeem hu ua charcoal, rosin, gum, tannins, cellulose.
Ntxhais ntoo muaj ntau pua lab xyoo laus dua txiv neej. Tag nrho cov kev vam meej uas tau muaj los ntawm kev siv ntoo. Phau ntawv, rooj tog, suab paj nruag - tag nrho cov no ua tau ua tsaug rau cov khoom siv ntuj tsim tshwj xeeb.
