Ua ntej, cov yam ntxwv: 1, Siab zog, siab toughness, siab creep kuj, siab torque: muaj feem xyuam rau cov yeeb nkab fittings, pob qij txha, valve lub cev, thiab lwm yam. 2, Kub kub tsis kam, hydrolysis tsis kam, UV tsis kam: cov khoom siv kho mob ...
Nyeem ntxiv