The moving magnet linear compressors are very popular in the tactical miniature stirling cryocoolers. The magnetic circuit of LFC3600 moving magnet linear compressor, manufactured by Kunming institute of Physics, was studied in this study. Three methods of the analysis theory, numerical calculation and experiment study were applied in the analysis process. The calculated formula of magnetic reluctance and magnetomotive force were given in theoretical analysis model. The magnetic flux density and magnetic flux line were analyzed in numerical analysis model. A testing method was designed to test the magnetic flux density of the linear compressor. When the piston of the motor was in the equilibrium position, the value of the magnetic flux density was at the maximum of 0.27T. The results were almost equal to the ones from numerical analysis.
This paper presents the difference between object recognition for satellite image and general object recognition. To
overcome the difficulties of object recognition for satellite image, two methods are proposed in this paper. First, it is
shown that traditional moment invariants are no longer invariant while object shape is distorted or contour is blurry. This
paper proposes an improved invariable moment algorithm, which reconstructs seven invariants moment formulas, and
weakens the sensitivity on distorted border. Moreover, a 3D model database including all interested target's 3D model
can be established. When starting to recognize the target in satellite image, several 2D projection images can be retrieved
from the model database, using these images as recognition templates will be more accurate than using a single target
image. Experimental results show that the methods presented in this paper are effective on satellite image recognition.