Abstract: Disclosed is a method for determining three-dimensional in-situ stress based on displacement measurement of borehole wall, including the following steps: selecting a testing borehole section for in-situ stress testing; arranging 6-9 measurement points in the testing borehole section; using a coring drill to perform a radial cut around the displacement measurement device to relieve the stress at the measurement point; cutting off the drilled core by the coring drill; recovering the sidewall coring device and removing the cores, and then measuring the elastic deformation parameters of each core; The beneficial effect of the technical scheme proposed in this disclosure is: the method provided by this disclosure overcomes the disadvantage that the measurement can only be performed at the bottom of a borehole and thus it has a wider application range.

Abstract: Disclosed is a method for determining three-dimensional in-situ stress based on displacement measurement of borehole wall, including the following steps: selecting a testing borehole section for in-situ stress testing; arranging 6-9 measurement points in the testing borehole section; using a coring drill to perform a radial cut around the displacement measurement device to relieve the stress at the measurement point; cutting off the drilled core by the coring drill; recovering the sidewall coring device and removing the cores, and then measuring the elastic deformation parameters of each core; The beneficial effect of the technical scheme proposed in this disclosure is: the method provided by this disclosure overcomes the disadvantage that the measurement can only be performed at the bottom of a borehole and thus it has a wider application range.

Abstract: A wound dressing comprising acylated chitosan fibre. The dressing has a wet strength of 0.3 N/cm or above. The acylated chitosan fibre may have a degree of substitution of 0.10-0.50. The acylated chitosan fibre may preferably have a degree of substitution of 0.20-0.40. The dressing may have an absorbency of 5-25 g/g of a solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate as measured by BSEN 13726-12002 Part 1 Aspects of Absorbency. The base material of the dressing may be chitosan fibre that has been chemically modified through an acylation process using anhydride and ethanol as the solvent. A method of manufacturing the wound dressing involves reacting chitosan fibre with anhydride and making acylated chitosan felt through a nonwoven process, and through cutting, packing and sterilizing processes.

Abstract: A wound dressing with bacteriostatic and hygroscopicity, preparation method therefore, and the use thereof in preparing a product for treating chronic wounds. The dressing comprises chitosan fiber and modified cellulose fiber.