Cov txheej txheem ntawm cov txheej txheem iav yog qhov tsis xwm yeem, thiab nws cov lwg me me sib luag zoo li qub hauv chaw. Hauv lub xeev zoo tagnrho, cov khoom siv lub cev thiab tshuaj ntawm cov homogeneous iav (xws li qhov ntsuas tsis tau yooj yim, lub zog tawv, elastic qauv, thermal nthuav coefficient, thermal conductivity, hluav taws xob conductivity, thiab lwm yam) yog tib yam hauv txhua qhov kev qhia.
