Dej ntub dej ntws yog ib qho txaj uas tsis muaj teebmeem uas siv lub dav hlau dej los rub ib rab phom los ntawm txoj hlua. Qhov dej thaiv dav hlau uas muaj qhov dej txhuam muaj qhov sib zog ua kom muaj zog tshaj li qhov tshuab pa taws, thiab lub diffusion yog qhov me me, thiab nws tsim nyog rau cov kev xav tau ntawm qhov chaw siv lub hlab ntsha ntawm hluavtaws fibers xws li cov pa thiab cov iav fibers. Nyob rau tib lub sijhawm, cov khoom siv hluav taws xob hluav taws xob yuav ua kom muaj zog thiab qhov hluav taws xob zoo li qub hauv cov phom tuaj yeem ua kom zoo. Tsis tas li ntawd, kev siv tshuaj pleev rau lub cev tsis haus tsawg zog thiab muaj lub suab qis tshaj.
