Cov khoom ntim khoom siv hluav taws xob
Cov khoom ntim khoom siv hluav taws xob xa mus rau cov khoom siv hauv paus siv los nqa cov khoom siv hluav taws xob thiab lawv cov kev sib tshuam, ua lub luag haujlwm ntawm kev txhawb nqa tshuab, foob ib puag ncig tiv thaiv, thiab dissipate cua sov ntawm cov khoom siv hluav taws xob, thiab muaj hluav taws xob zoo. Nws yog lub cev sealing rau kev sib xyaw ua ke.