A study on the detection of weathering in the Yungang Grottoes using non-Hermitian wireless sensing

As a world cultural heritage, the Yungang Grottoes have been deeply affected by weathering and other damage. Detecting the degree of weathering in stone carvings is an important technical support for conserving stone cultural relics. The weathering degree is the basis for determining the weathering rate, as well as identifying weathered parts or changes in the material properties. To obtain information about the weathering degree of these caves, this study used a non-Hermitian high-sensitivity microwave wireless-sensing system to carry out detection studies on stone samples from the Yungang Grottoes. The resonant-frequency response in this wireless-sensing system varies with the weathering degree of the samples. In addition, the characteristic curve, fitted by the relationship between the content of the main constituents of the samples and the resonant-frequency response, is used to predict the weathering degree of unknown samples. Detecting the weathering of the Yungang Grottoes using a non-Hermitian wireless-sensing system can provide new detection methods and technical guidance for conserving these caves.