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排序方式: 共有152条查询结果,搜索用时 15 毫秒
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Eigenvalue cycles for robust control systems   总被引:1,自引:1,他引:0  
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A novel magnetic sensing technology that forms the basis of an innovative system to monitor ground vehicle movements at airports is presented. The operating principle of this system is the detection of interaction of aircraft or ground vehicles with the earth?s magnetic field using sensitive magnetic field detectors. After development and laboratory testing of the detectors, test sites have been set up at three European airports. Potential applications of the detectors were designed and demonstrated. Tests have shown that the system can be applied for ground movement surveillance. The approach can be used as a complementary surveillance system for existing and future advanced surface movement guidance and control systems (A-SMGCS) at large airports or as a cost-effective stand-alone solution for monitoring critical areas at medium and small airports. Furthermore, this system can be applied as well in road traffic and car park occupancy monitoring. Unaffected by weather conditions, interference and shadowing effects, the system provides reliable vehicle position, velocity and direction information without requiring any equipment in aircraft or ground vehicles and thus it increases airport operational safety.  相似文献   
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The characterization of Si-B-C-N amorphous ceramics using isothermal compression creep testing in the temperature range of 1200°–1500°C is reported. The deformation rate contains a stress-dependent component that is proportional to the applied stress, which indicates that this portion of the deformation mechanism is based on viscous flow. An increase in the creep resistance is observed, following either preliminary annealing or hot isostatic pressing, which may be explained by a reduction of free volume in the amorphous material. The application of two deformation models that are used to predict similar deformation behavior in metallic glasses also is discussed. Although both models accurately predict the time dependence of the deformation rate of precursor-derived amorphous ceramics, the free-volume model fits the observed temperature dependence better than the "two-step" rearrangement model.  相似文献   
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We report the case of a patient with a rare miliary variant of osteosarcoma associated with symptomatic hypocalcemia and review the literature regarding the pathogenesis of multifocal osteosarcoma, treatment options, and the associated hypocalcemia.  相似文献   
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