Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
불투열성은 열의 전도를 방지하는 성질입니다.Bultuyeolseong-eun yeol-ui jeondoreul bangjihaneun seongjil-imnida.Athermancy is the property that prevents the conduction of heat.