rotating view
1.Combined PET/CT examinations were performed in 12 cases, the scanner was Discovery Ls(GE)which included Advance 2 PET scanner and Light speed spiral CT scanner, the scan parameters were as following: tube voltage 140Kv, tube current 90mA～200mA, slice thickness 5mm,patch 0.75,rotating time per ring 0.8s, scanning field of view(FOV)50cm;
2.As a result of the heightening of mechanical operation speed and the application of new materials and new structures,the nonlinear dynamic behavior in rotating machines is becoming increasingly outstanding and important.Nonlinear dynamic phenomena in rotating machines cant be described,explained and predicted by rotordynamics based on linear system theory.Along with the deepening and permeating of nonlinear scientific research,the nonlinear vibration of rotor systems has become an attractive field in recent years.From a point of view to set up the distinct corresponding relations between vibration states and failures of rotating machines,main advances in the research of rotor nonlinear vibration are summarized ,and typical nonlinear dynamic phenomena and their forming mechanism are also summed up in the paper.The aim of the paper is to enrich the diagnostic knowledge base of rotating machines.55refs.
