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PURPOSE To improve the performance of non-Cartesian partially parallel imaging (PPI) by exploiting artificial sparsity, the generalized autocalibrating partially parallel acquisitions (GRAPPA) operator for wider band lines (GROWL) is taken as a specific example for explanation. THEORY This work is based on the GRAPPA-like PPI having an improved(More)
The uniformity of the static magnetic field B0 is of prime importance for an MRI system. The passive shimming technique is usually applied to improve the uniformity of the static field by optimizing the layout of a series of steel shims. The steel pieces are fixed in the drawers in the inner bore of the superconducting magnet, and produce a magnetizing(More)
Based on a method used to calculate the magnetic field in a thin clearance between superconducting blocks, this paper analyzes the force characteristics of the superconducting passive suspension system. Superconducting magnetic suspension system is an essentially self-stabilization system. At the basis of the existing structure, an electrostatic suspension(More)
It occurred a large-scale landslide in the Three Gorges Reservoir, Qianjiangping village, shazhenxi town, Zigui County on July 13, 2003, causing serious economic losses and casualties. The digital telemetry seismic network in the Three Gorges Reservoir recorded a complete landslide sliding process of ground vibration, and obtained five micro-fracture events(More)