... is 300MHz to 300GHz .The water molecule in medium materials is polar molecule,under the effect of the rapid ... heat energy in medium to rise the temperature of materials.accomplishing heating ,puffing and a series of physical and ... , chemical fiber, cotton yarn, wood, leather, bamboo products, insulation materials, building materials, wood , cork, alveolate, cardboard,corrugated cardboard, and so on.4 ...