This paper presents an all-SiC fiber-optic Fabry-Perot (FP) pressure sensor based on the hydrophilic direct bonding technology for the applications in the harsh environment. The operating principle, fabrication, interface characteristics, and pressure response test of the proposed all-SiC pressure sensor are discussed. The FP cavity is formed by hermetically direct bonding of two-layer SiC wafers, including a thinned SiC diaphragm and a SiC wafer with an etched cavity. White light interference is used for the detection and demodulation of the sensor pressure signals. Experimental results demonstrate the sensing capabilities for the pressure range up to 800 kPa. The all-SiC structure without any intermediate layer can avoid the sensor failure caused by the thermal expansion coefficient mismatch and therefore has a great potential for pressure measurement in high temperature environments.
The shortage of land resources on the Loess Plateau has long been a thorny problem. Many high-fill projects are carried out, accompanied by a series of geological hazards, which threaten the ecological environment and personal safety. The creep characteristics of loess are an essential part of loess landslide research. The microstructural changes are closely related to creep behavior. By conducting triaxial creep experiments on Malan loess from the Yan’an area in China, scanning electron microscope (SEM) experiments on loess in different creep stages were carried out. Using qualitative and quantitative analyses of the microstructural characteristics of intact loess and remodeled loess during creep, the microstructural parameters were compared, and finally, the microscopic mechanisms during creep were analyzed. The qualitative analysis of remodeled loess during creep returned significantly higher results than it did for intact loess. During the creep process, among the microstructural parameters of loess change, the change in pore and particle size and shape were the most obvious, while the complexity of other microstructural parameters and orientation changed little. During the creep process of loess, the soil skeleton changed continuously, but the loess microstructure featured different changes at different levels of deviator stress.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.