Abstract: An experimental device and method for simulating a subsurface erosion process is disclosed, including a constant-pressure water supply device, a subsurface erosion generator, and a water-soil collection device. The constant-pressure water supply device and the subsurface erosion generator communicate with each other by a pipeline. The constant-pressure water supply device is used to simulate a natural water flow in subsurface erosion. The subsurface erosion generator is used to carry sand and display the occurrence process of water-soil subsurface erosion. The water-soil collection device is used to collect soil and water loss data required for an experiment. In accordance with the experimental device, the water-soil subsurface erosion process can be accurately displayed, a water pressure can be adjusted as needed, and a height between the constant-pressure water supply device and the erosion generator can be adjusted to simulate the terrain.

Abstract: Provided are a method and device for measuring a respiratory rate, an electronic device, and a readable medium, which belong to the technical field of respiratory rate monitoring. The method for measuring a respiratory rate includes: acquiring a PPG signal; performing a preprocess on the PPG signal; acquiring PPG interval data and a PPG interval variation valve according to a pretreated PPG signal, wherein the PPG interval variation value refers to a difference between two adjacent PPG intervals in the PPG interval data; when there is no the abnormal PPG interval variation value in PPG interval data, calculating the respiratory rate according to the PPG interval data; and when there is the abnormal PPG interval variation value in PPG interval data, correcting the PPG interval data, and calculating the respiratory rate according to corrected PPG interval data. Therefore, the accuracy of measurement of a PPG interval variation can be improved, thereby reducing a measurement error of the respiratory rate.

Abstract: The present disclosure relates to a method for manufacturing graphene based on a mixed inorganic acid solvent. By using the inorganic acid solvent with simple preparation and low-cost instead of expensive organic solvent to perform a solvent stripping method for manufacturing graphene products, it may avoid the problems of high toxicity and harsh preparation conditions caused by using organic solvents, reduce the requirement on temperature in the graphene preparation process of the solvent stripping method, and reduce the time required by graphene stripping treatment; thereby simplifying the preparation process, and facilitating the commercialization and large-scale development of the method for manufacturing graphene by the solvent stripping method.