A method of characterizing phase transformations of a shape memory material specimen entails recording data from the specimen during heating and cooling. The adhesive is allowed to pre-cure on the surface until the adhesive is no longer sticky and then the bearing ring and the component are joined in a desired relative position, such a radial distance between a base of the at least one annular groove-shaped receiving space and the component is larger than a radial distance between the surface and the component. For example, the material of discharge chamber sidewall is stainless steel o aluminum, the material of grids is Mo, W or C and the material of platform is Ti or Mo. An angle holding unit is provided between the front or back cover and the corresponding front or back collapsing cover to hold an angle between the front or back cover and the corresponding front or back collapsing cover.