Siv cov khoom ntsuas dej los ntsuas cov dej noo thiab cov khoom ntoo
1. Qhov chaw thiab lub xeev ntawm noo noo nyob rau hauv ntoo
Thaum tsob ntoo muaj sia loj hlob, nws cov hauv paus hniav tsis tu ncua nqus dej los ntawm cov av, thiab xylem ntawm lub cev xa dej mus rau ntau yam kabmob ntawm tsob ntoo, thiab tib lub sijhawm, cov as-ham uas tsim los ntawm photosynthesis ntawm nplooj yog thauj los ntawm phloem ntawm cov nroj tsuag. pob tw rau ntau yam kabmob ntawm tsob ntoo. ib feem. Cov dej noo tsis yog tsuas yog cov khoom tseem ceeb tshaj plaws rau kev loj hlob ntawm tsob ntoo, tab sis kuj yog cov cab kuj rau cov ntoo kom thauj ntau yam khoom. Tom qab tsob ntoo muaj sia raug txiav thiab saws rau hauv ntau yam tshwj xeeb ntawm cov laug cam thiab squares, feem ntau ntawm cov dej tseem nyob hauv cov ntoo, uas yog cov dej noo hauv cov ntoo. Nyob rau tib lub sijhawm, ntoo tseem yuav nqus qee cov dej noo rau hauv nws sab hauv thaum khaws cia, thauj lossis siv.
Rau ntau hom ntoo, cov dej noo ntawm xylem hauv lub cev yog txawv. Txawm tias tib tsob ntoo muaj cov ntsiab lus dej sib txawv hauv nws cov xylem hauv cov caij nyoog sib txawv. Txhua feem ntawm xylem, xws li heartwood, sapwood, hauv paus, pob tw thiab treetop, muaj cov ntsiab lus dej sib txawv, yog li cov dej faib hauv ntoo tsis sib xws. Thaum cov huab cua nyob ib puag ncig ntoo hloov, nws cov dej noo kuj yuav hloov raws li. Cov dej noo tuaj yeem muab faib ua peb hom: dej dawb, dej adsorbed, thiab dej ua ke vim nws txoj haujlwm sib txawv hauv cov ntoo:
(1) Cov dej dawb muaj nyob rau hauv cov kab mob loj capillary uas tsim los ntawm cov pits ntawm phab ntsa ntoo lossis qhov perforation ntawm qhov kawg ntawm cov kav dej, cov kab noj hniav ntawm tes thiab qhov chaw intercellular. Cov dej dawb yog lub cev ua ke nrog ntoo, thiab kev sib xyaw ua ke tsis nruj. Qhov no ntawm cov dej Nws yog ib qho yooj yim kom dim ntawm cov ntoo, thiab nws kuj yog ib qho yooj yim rau nqus tau pa. Thaum cov ntoo ntub tau muab tso rau hauv huab cua qhuav, thawj qhov uas yuav ua rau evaporate yog dej dawb. Rau cov ntoo nyoos tshiab, cov dej dawb ntawm cov ntoo sib txawv txawv heev, feem ntau ntawm 60 ~ 70 feem pua thiab 200 ~ 250 feem pua.
(2) Adsorbed dej muaj nyob rau hauv lub micro-capillary system tsim ntawm microfibrils thiab macrofibrils nyob rau hauv ntoo cell phab ntsa los yog adsorbed ntawm dawb radicals ntawm cellulose molecules nyob rau saum npoo ntawm microcrystal thiab nyob rau hauv lub amorphous cheeb tsam. Adsorbed dej hauv ntoo Muaj qhov sib txawv me ntsis ntawm cov ntsiab lus ntawm cov ntoo. Cov ntsiab lus siab tshaj plaws ntawm cov dej nqus los ntawm cov ntoo yog feem ntau ntawm 23 feem pua thiab 31 feem pua, thiab qhov nruab nrab yog li 3 feem pua. Cov dej nqus tau zoo sib xyaw nrog cov khoom siv ntoo, thiab cov dej no tsis yooj yim rau kev khiav tawm ntawm cov ntoo. Tsuas yog thaum cov dej dawb hauv cov ntoo evaporates tag nrho, thiab ib nrab siab ntawm cov dej vapor hauv cov ntoo yog siab dua ib feem ntawm cov dej vapor nyob rau hauv cov phab ntsa cua, nws tuaj yeem evaporate los ntawm cov ntoo.
(3) Cov dej sib xyaw ua ke thiab cov phab ntsa ntawm tes yog nyob rau hauv kev sib xyaw tshuaj muaj zog. Cov ntsiab lus ntawm cov dej no hauv cov ntoo yog me me thiab tuaj yeem tsis quav ntsej, thiab nws tsis tuaj yeem raug tshem tawm raws li qhov qub qhuav.
2. Ntoo ya raws thiab ib puag ncig sab hauv tsev
Nyob rau hauv ib puag ncig sab hauv tsev uas tib neeg nyob, cov av noo yuav tsum tsis txhob hloov pauv ntau dhau, thiab yuav tsum ruaj khov nyob rau hauv ib qho chaw, uas muaj txiaj ntsig zoo rau tus kheej kev noj qab haus huv thiab kev khaws cia ntawm cov khoom. Cov ntaub ntawv tshawb fawb qhia tias: qhov txheeb ze av noo ntau los tiv thaiv pwm ntub yog 0-80 feem pua ; rau kev tiv thaiv kab puas tsuaj, nws yog 0-70 feem pua lossis 80-100 feem pua ; rau khaws cia cov phau ntawv, nws yog 40-60 feem pua ; tiv thaiv kab mob, nws yog 55-60 feem pua ; Tus nqi qis tshaj yog 60-70 feem pua, thiab cov av noo ntawm tib neeg nyob ib puag ncig yuav tsum nyob ib ncig ntawm 60, uas yog qhov tsim nyog dua.
Muaj ntau yam uas ua rau muaj kev hloov pauv ntawm cov av noo nyob hauv tsev, piv txwv li: kev hloov pauv ntawm qhov kub thiab txias sab hauv tsev yuav ua rau cov av noo hloov pauv; dej vapor ntws los hauv lossis tawm ntawm qhov transom lossis qhov cua qhib, dej vapor nkag los ntawm phab ntsa, dej vapor los ntawm chav ua noj, thiab lwm yam. Nws kuj tuaj yeem ua rau cov av noo hloov pauv.
Cov av noo tswj cov cuab yeej ntawm ntoo yog ib qho ntawm cov khoom tshwj xeeb ntawm cov ntoo, thiab nws kuj yog qhov zoo ntawm nws ua cov khoom siv kho kom zoo nkauj sab hauv thiab cov khoom siv rooj tog. Cov av noo hloov ntawm lub tsev dai kom zoo nkauj nrog cov ntoo lossis cov ntaub ntawv ntoo yog nrawm dua li cov vaj tsev pob zeb lossis cov tsev dai kom zoo nkauj nrog cov ntawv ntsa. Me me. Lub thiaj li hu ua noo noo-regulating yam ntxwv ntawm ntoo yog ncaj qha alleviate cov av noo hloov ntawm ib puag ncig sab hauv tsev los ntawm noo noo nqus thiab desorption ntawm ntoo nws tus kheej. Thaum tus txheeb ze av noo ntawm ib puag ncig sab hauv tsev txo qis, cov dej vapor ib nrab siab sib npaug ntawm qhov chaw sab hauv tsev thiab cov ntoo tawg. Cov dej vapor ib nrab siab hauv cov ntoo yog siab dua li ntawm ib puag ncig sab hauv tsev, thiab cov dej noo hauv cov ntoo yuav dim. Ua kom tus txheeb ze humidity ntawm ib puag ncig sab hauv tsev, uas yog cov txheej txheem desorption. Hloov pauv, thaum cov av noo ntawm qhov chaw sab hauv tsev nce, ntoo yuav nqus dej noo los ntawm huab cua sab hauv, uas yog txheej txheem hygroscopic. Thaum pib ntawm cov txheej txheem desorption los yog noo noo nqus, cov ntoo ua tau zoo heev, tom qab ntawd nws maj mam qeeb kom txog rau thaum muaj qhov sib npaug tshiab. Ntawm no ntoo ua raws li kev cia ntawm noo noo, ib yam li lub ntuj regulator ntawm huab cua nyob hauv tsev. Cov neeg tau txais kev coj ua nyob rau hauv ib puag ncig ntawm cov rooj tog ntoo thiab cov khoom siv kho kom zoo nkauj hauv tsev rau lub sijhawm ntev.
3. Cov dej noo ntawm cov ntoo thiab cov duab thiab qhov loj ntawm nws cov khoom
Cov dej noo ntawm cov ntoo cuam tshuam rau lub zog, rigidity, hardness, decay resistance, mechanical processing performance, combustion value, thermal conductivity, hluav taws xob conductivity, thiab lwm yam ntawm ntoo nyob rau hauv ib tug tej yam ntau yam.
Thaum cov ntoo ntub dej tau muab tso rau hauv qhov chaw qhuav, vim tias qhov siab ntawm ib nrab ntawm cov dej vapor hauv cov ntoo yog siab dua qhov siab ntawm ib nrab ntawm atmospheric dej vapor, cov dej yuav tawm ntawm sab hauv ntawm ntoo mus rau qhov chaw, thiab cov dej dawb. yuav evaporate ua ntej. Thaum cov dej dawb hauv cov ntoo evaporates tag nrho thiab cov dej adsorbed tseem nyob hauv lub xeev saturated, cov dej noo hauv lub xeev ntawm cov ntoo hu ua fiber ntau saturation point, thiab fiber ntau saturation point yog qhov hloov pauv ntawm cov khoom ntoo. Thaum cov dej noo ntawm cov ntoo hloov siab tshaj qhov taw tes fiber ntau, vim tias qhov kev hloov ntawm cov dej noo tsuas yog nce lossis txo cov dej dawb xwb, thiab qhov nce lossis txo cov dej dawb muaj me ntsis cuam tshuam rau cov khoom ntawm ntoo. , tsuas yog cuam tshuam rau qhov hnyav, combustion nqi, thermal conductivity thiab conductivity. Piv txwv li, thaum cov dej noo ntawm cov ntoo hloov hauv qab ntawm cov fiber ntau saturation point, vim tias tsis muaj dej dawb hauv cov ntoo, qhov kev hloov ntawm cov dej absorbed muaj kev cuam tshuam zoo rau cov khoom ntawm ntoo, xws li cov khoom siv ntawm cov ntoo. , drying shrinkage, o, thermal conductivity thiab hluav taws xob conductivity. Nws tuaj yeem hais tau tias cov dej nqus hauv cov ntoo yog qhov tseem ceeb cuam tshuam rau cov khoom ntawm ntoo.
Tsis tas li ntawd, thaum muaj ib qho chaw tsim nyog xws li huab cua, khoom noj khoom haus, kub, thiab av noo, cov spores ntawm cov ntoo-rot fungus yuav kis tau ntoo thiab ua rau muaj kev puas tsuaj rau ntoo. Qhov zoo tshaj plaws kub rau kev loj hlob ntawm feem ntau ntoo-rot fungi yog 25-30 degree, thiab qhov zoo tshaj noo noo ntsiab lus yog 35-50 feem pua. Yog hais tias cov av noo ntawm cov ntoo raug txo mus rau 2 feem pua, cov kev ua ntawm cov ntoo-rot fungi yuav raug inhibited, yog li ziab kuj yog los tiv thaiv ntoo los ntawm discoloring Kev ntsuas ntawm kev lwj.
Nyob rau hauv peb lub neej niaj hnub, qhov uas peb muaj feem ntau yog qhov qhuav shrinkage thiab ntub expansion yam ntxwv ntawm ntoo, uas yog ib tug zoo kawg li feature ntawm ntoo. Tom qab cov ntoo tshiab tau muab hlais rau hauv cov laug cam thiab squares, lawv yuav pib tawm cov dej noo thaum muab tso rau hauv qhov chaw qhuav heev. Ua ntej, cov dej dawb hauv cov ntoo yuav pib khiav, thiab qhov loj ntawm cov ntoo yuav tsis hloov raws li. Thaum cov dej dawb hauv cov ntoo evaporates, cov dej adsorbed hauv cov phab ntsa ntawm cov ntoo yog tawm ntawm cov ntoo, thiab qhov loj ntawm cov ntoo txo. Qhov no yog vim qhov sib txawv ntawm cov microfibrils thiab macrofibrils nyob rau hauv lub cell phab ntsa yog txo vim qhov paug ntawm absorbed dej, uas ua rau lub cell phab ntsa thinner thiab ua rau cov ntoo shrinkage. Ntawm qhov tsis sib xws, thaum ntoo maj mam wetted los ntawm lub xeev qhuav tag mus rau qhov taw tes fiber ntau, qhov tshwm sim ntawm cov ntoo o tuaj yeem pom.
Kev ziab kom qhuav thiab ntub dej nthuav dav ntawm ntoo ua rau qhov ntev ntawm cov khoom ntoo tsis ruaj khov. Vim yog anisotropy ntawm cov qauv ntoo, ntoo shrinkage sib txawv heev vim qhov sib txawv ntawm cov kev taw qhia, tsob ntoo hom, ntom, latewood tus nqi, kev loj hlob nplhaib dav, kev ntxhov siab ntoo, thiab tshuaj lom neeg muaj pes tsawg leeg ntawm cov phab ntsa ntawm tes. Yog li ntawd, qhov ziab qhuav thiab ntub dej nthuav dav ntawm ntoo kuj tseem muaj anisotropy, uas yog feem ntau tshwm sim nyob rau hauv hais tias qhov ntev shrinkage tus nqi raws lub cev kev taw qhia me me, txog {{0}}.10 ~ 0.20, thiab cov radial. shrinkage tus nqi raws lub cev vojvoog kev taw qhia yog hais txog 3 ~ 6 feem pua; chord shrinkage tus nqi ntawm ntoo raws lub nplhaib txhua xyoo kev taw qhia yog kwv yees li ob zaug ntawm radial shrinkage tus nqi, txog 6 ~ 12 feem pua, vim hais tias qhov tsis sib xws ntawm shrinkage ntawm txhua feem hloov nws cov duab.
Thaum cov ntoo nyoos qhuav, vim qhov sib xyaw ua ke ntawm qhov sib txawv ntawm qhov shrinkage nyob rau hauv radial kev taw qhia thiab chord kev taw qhia, qhov kawg lub ntsej muag ntawm plank square lumber unsawed los ntawm lub cav yuav undergo ntau yam deformations, xws li warping, dabtsi yog khoov, twisting. , thiab transverse dabtsi yog khoov. Vim yog qhov tsis sib xws ntawm qhov ziab thiab qhov sib txawv ntawm qhov shrinkage nyob rau hauv cov kev taw qhia sib txawv, cov ntoo yuav ua rau cov kab nrib pleb, qhov kawg ntawm cov kab nrib pleb, cov kab nrib pleb, lub plawv tawg, cov kab nrib pleb tawg, lub log tawg thiab lwm yam tsis xws luag.
Qhov sib npaug ntawm cov dej noo ntawm cov ntoo yog qhov tseem ceeb hauv kev ua thiab siv ntoo. Nws lub luag haujlwm yog tias nws ua rau tib neeg paub tias ua ntej ntoo yuav ua rau cov khoom ntoo, nws yuav tsum tau qhuav rau cov ntoo sib npaug ntawm cov dej noo uas tsim nyog rau huab cua kub thiab av noo hauv cheeb tsam. Nyob rau hauv txoj kev no, kev hloov pauv ntawm cov dej noo ntawm cov ntoo vim qhov kub thiab av noo ntawm thaj chaw ntawm kev siv tuaj yeem zam tau, thiab nws yuav tsis ua rau muaj kev hloov pauv ntawm qhov loj lossis cov duab ntawm cov ntoo, yog li ua kom cov ntoo zoo. cov khoom. Peb lub teb chaws muaj thaj chaw loj heev, thiab qhov sib npaug ntawm cov dej noo ntawm cov ntoo hauv ntau thaj chaw txawv heev nyob ntawm qhov kev nyab xeeb ntawm txhua cheeb tsam. Txawm nyob hauv tib cheeb tsam, qhov sib npaug ntawm cov dej noo ntawm cov ntoo hauv cov caij sib txawv kuj txawv. Piv txwv li, qhov nruab nrab txhua xyoo nruab nrab noo noo cov ntsiab lus ntawm cov ntoo hauv Beijing yog kwv yees li 11.1 feem pua, qhov siab tshaj plaws yog 15.6 feem pua hauv lub Yim Hli, thiab qhov qis tshaj yog li 8.5 feem pua hauv lub Plaub Hlis.
