Fig. 3From: Determination on the thickness of superficially weathered layer of historical stones from Guanzhong area in ChinaDemonstration of sample preparation of (a) ultrasonic velocity method and (b) vapor absorption method. Sample S4, S5, S6, S7, S8, S10, S13 and S15 are columns of 5 cm in diameter and height of 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 10 mm, 13 mm and 15 mm, respectivelyBack to article page