18.Bullae are rounded or irregularly shaped blisters containing serous or seropurulent fluid.They differ from vesicles only in size, being larger than 1 cm.
19.Compared with the conventional presplitting methods, the shaped charge is obviously more effective in presplitting blasting and especially useful in controlling the presplitting slots.
20.Chlorinated Polyethylene (CPE) is a macromolecule and orderless chloride of Polyethylene.It is a rubber shaped plastic, which after being vulcanization treatment, can turn into elastic rubber.