Detachment is one of the most serious types of deterioration to endanger the stability and safety of ancient murals. Due to various constraints，several limitations remain that significantly impact current research on the mechanisms underlying detachment，quantitative assessment methods，and key grouting technologies. Furthermore，it is important to note that these limitations will have a direct impact on the efficacy of the treatment of detached murals. By systematically analyzing the mechanisms underlying mural detach ment，and by evaluating the available monitoring technologies，quantitative standards and repair materials currently being implemented，this paper provides an in -depth discussion of the key technical bottlenecks and potential directions of development for this area of mural conservation. The aim of this study is to provide a theoretical basis and practical foundation for the construction of a scientific，standardized system for the prevention and treatment of mural detachment.

As a result of the humid environment where the cave murals of the Maijishan Grottoes are located，and due to the poor adhesion of their support layers，the plaster layers in many of the murals at this site have deteriorated severely. In order to investigate the distribution patterns and analyze the formation mechanisms of the damage，42 relatively enclosed caves with intact structures were selected for study，the results of which show that there has been a significant loss of plaster in all the caves. In 8 （19%） of the selected caves，a complete loss of the plaster layer across all the walls was observed，and 21 （50%） of the caves exhibited either complete loss on a single wall or in a relatively large area； on average，42% of the total wall surface of the selected caves has experienced some loss of plaster. The spatial distribution of plaster layer loss reveals distinct patterns：the south walls and the lower parts of the caves exhibit damage mainly caused by external forces；the loss of plaster is most severe on the north walls，which are most prevalent to water-and seepage-induced weathering，and the ceilings have mainly been affected by fissure-percolation type deterioration. Analysis of the mechanisms that caused the damage indicates that this phenomenon resulted from coupled factors related to rock mass properties，moisture diffusion，and mechanical interventions. In particular，shallow-layer rock weathering primarily caused by moisture diffusion and certain characteristics in the rock mass was found to be the dominant trigger for the loss of plaster，while synergistic action combined with other factors lead to the distinct areas of large-scale deterioration. This study is meant to provide a foundation for developing preventive strategies and future research on the conservation of the Maijishan cave murals.

More than one-tenth of the over 400 extant caves that contain murals at the Mogao Grottoes in Dunhuang exhibit varying degrees of fire-induced damages. According to field investigations，studies of fire damage at the Mogao Grottoes，and historical records，this paper has identified the general features associated with fire-induced damage suffered by the paintings，as well as the most significant historical events related to fires inside the caves. On this basis，the causes，characteristics，and current distribution of the damages to the wall paintings have been systemically examined and summarized. The investigation results indicate that the formation and patterns of fire damage are closely related to the functional attributes of a given site，the type of fire source，the size of the cave，and the architectural structure of the cave. The principal sources of fire in the caves included religious activities，fires used for daily activities，and fires resulting from specific historical events，all of which led to the widespread distribution of soot throughout the caves. This study also highlights the variety and complexity of the fire-induced damages currently affecting the murals at Dunhuang，as well as the necessity for further interdisciplinary research.

The Xianrenya Grottoes site，which is also known as the “Immortal Cliff”，is renowned for its exquisite sculptural art that includes many vividly painted statues of Buddhas，Bodhisattvas，and Arhats that are characterized by their smooth and natural lines，and by the diversity of their painting techniques. Focusing on the statue of master Hui Ke in the Manjusri Hall，the second patriarch of the Chan Sect of Chinese Buddhism，this study present a systematic research report on the materials and techniques of the statue by conducting X-ray diffraction（XRD），laser particle size analysis（PSA），scanning electron microscopy with energy dispersive spectroscopy（SEM-EDS），Fourier-transform infrared spectroscopy （FTIR），and pyrolysis-gas chromatography-mass spectrometry （Py-GC/MS）. The results indicate that the statue is a clay statue with a wooden core whose structure consists of a wooden skeleton bound with reeds，a fiber-reinforced clay body，a base coating layer， a painted layer，and a final decorative layer with gravel and protective gold-leaf. The clay body contains quartz，feldspar，and calcite，with an average particle size of 38.1 μm and a well distributed gradation；cotton fiber was used as a reinforcement material. The pigments identified in the paint include hematite，cinnabar，red lead，atacamite，and gypsum. Furthermore，this research has found that the statue features a unique “gravel decoration technique”that involves pasting a protein-based adhesive sandstone to the pigment layer and then sealing it with boiled

Mogao cave 55 was originally dug in the early Song dynasty，and later renovated in the Western Xia period. Most of the murals and paintings in the cave were made with gilded decorations and therefore provide rare firsthand material for the study of Song dynasty gilding. This study conducts acomprehensive analysis of the materials and techniques used to create the gilding on the painted statues in cave 55 by utilizing various analytical methods，including portable X-ray fluorescence spectroscopy，microscopic observation，X-ray diffraction spectroscopy，scanning electron microscopy-energy dispersive X-ray spectroscopy，confocal micro-Raman spectroscopy，and Fourier transform infrared spectroscopy. The results have revealed that both the Song and Western Xia dynasty gilding includes layers of gold foil，jinjiao （gold glue），and a preparation layer，but also that the materials used in each layer differ between historical periods. The gold foil used in the Western Xia restoration are purer and thicker than those originally applied during the Song dynasty；the jinjiao layer from the Song dynasty was made by mixing hematite with cementing materials，whereas the jinjiao materials from later periods mainly contains lead dioxide （which may be the discoloration product of red lead），and finally；the preparation layer applied during the Song Dynasty was made of orpiment，while that of the Western Xia renovation was hydrous lead white or arsenopyrite. These research results enrich our understanding of the painted statues in the Song dynasty caves at Mogao，provide important theoretical support for further scientific conservation of the deteriorated gilding on some the statues in Mogao cave 55，and also serve as valuable reference material for the study of traditional Chinese gilding techniques.