The controller plays an important rol e in microwave landing system(MLS) navigation equipment.The embedded advanced reduced-instruction-set-computing(RISC) machine(ARM) is introduced to de velop a new MLS controller b...The controller plays an important rol e in microwave landing system(MLS) navigation equipment.The embedded advanced reduced-instruction-set-computing(RISC) machine(ARM) is introduced to de velop a new MLS controller based on the functional requirements.A design includ ing hardware and software of an ARM system is given.The hardware design involve s a ARM smallest system and its interface.μC/OS-II,a good real-time operating system(RTOS),is i ntroduced in the software design.The task partitioning and management are also i nvolved.The experimental results demonstrate that the embedded ARM technique is an effective way in the complex multi-task system,and it meets the high inte gration and real-time processing requirements of the navigation equipment.展开更多
The heat-transfer behaviour of the conduction cold plate system used for avionics is investigated in this paper. The steady-state temperature profile for the cold plate is derived and the relationship between the cool...The heat-transfer behaviour of the conduction cold plate system used for avionics is investigated in this paper. The steady-state temperature profile for the cold plate is derived and the relationship between the coolant mass flowrate, the heat load and the hashest cold plate temperature is established.A model is proposed to describe the transient thermal rosponse of the cold plate under thermal shock condition. The analytic solution of the transient heat transfer within the cold plate is provided. The results of this paper agree with those of the finite element method and can be used for the structural design and performance evaluation of cold plate system.展开更多
Objective： To evaluate the accuracy of computer-assisted pedicle screw installation and its clinical benefit as compared with conventional pedicle screw installation techniques. Methods： Total 176 thoracic pedicle s...Objective： To evaluate the accuracy of computer-assisted pedicle screw installation and its clinical benefit as compared with conventional pedicle screw installation techniques. Methods： Total 176 thoracic pedicle screws placed in 42 thoracic fracture patients were involved in the study randomly, 20 patients under conventional fluoroscopic control （84 screws） and 22 patients had screw insertion under three dimensional （3D） computer-assisted navigation （92 screws）. The 2 groups were compared for accuracy of screw placement, time for screw insertion by postoperative thincut CT scans and statistical analysis by χ^2 test. The cortical perforations were then graded by 2-mm increments： Grade Ⅰ （good, no cortical perforation）, Grade Ⅱ （screw outside the pedicle 〈2 mm）, Grade Ⅲ （screw outside the pedicle 〉2 mm）. Results： In computer assisted group, 88 （95.65%） were Grade Ⅰ （good）, 4 （4.35%） were Grade Ⅱ （〈2mm）, no Grade Ⅲ （〉2 mm） violations. In conventional group, there were 14 cortical violations （16.67%）, 70 （83.33%） were Grade Ⅰ （good）, Ⅱ （13.1%） were Grade Ⅱ （〈2 mm）, and 3 （3,57%） were Grade Ⅲ （〉2 mm） violations （P〈0.001）. The number （19.57%） of upper thoracic pedicle screws （ T1-T4 ） inserted under 3D computer-assisted navigation was significantly higher than that （3.57%） by conventional fluoroscopic control （P〈0.001）. Average screw insertion time in conventional group was （4.56 ±1.03） min and （2.54 ± 0.63） min in computer assisted group （P〈0.001）. In the conventional group, one patient had pleura injury and one had a minor dura violation. Conclusions： This study provides further evidence that 3D computer-assisted navigation placement ofpedicle screws can increase accuracy, reduce surgical time, and be performed safely and effectively at all levels of the thoracic spine, particularly upper thoracic spine.展开更多
文摘The controller plays an important rol e in microwave landing system(MLS) navigation equipment.The embedded advanced reduced-instruction-set-computing(RISC) machine(ARM) is introduced to de velop a new MLS controller based on the functional requirements.A design includ ing hardware and software of an ARM system is given.The hardware design involve s a ARM smallest system and its interface.μC/OS-II,a good real-time operating system(RTOS),is i ntroduced in the software design.The task partitioning and management are also i nvolved.The experimental results demonstrate that the embedded ARM technique is an effective way in the complex multi-task system,and it meets the high inte gration and real-time processing requirements of the navigation equipment.
文摘The heat-transfer behaviour of the conduction cold plate system used for avionics is investigated in this paper. The steady-state temperature profile for the cold plate is derived and the relationship between the coolant mass flowrate, the heat load and the hashest cold plate temperature is established.A model is proposed to describe the transient thermal rosponse of the cold plate under thermal shock condition. The analytic solution of the transient heat transfer within the cold plate is provided. The results of this paper agree with those of the finite element method and can be used for the structural design and performance evaluation of cold plate system.
基金This study was supported by National Natural Science Foundationof China （No. 30772209）.
文摘Objective： To evaluate the accuracy of computer-assisted pedicle screw installation and its clinical benefit as compared with conventional pedicle screw installation techniques. Methods： Total 176 thoracic pedicle screws placed in 42 thoracic fracture patients were involved in the study randomly, 20 patients under conventional fluoroscopic control （84 screws） and 22 patients had screw insertion under three dimensional （3D） computer-assisted navigation （92 screws）. The 2 groups were compared for accuracy of screw placement, time for screw insertion by postoperative thincut CT scans and statistical analysis by χ^2 test. The cortical perforations were then graded by 2-mm increments： Grade Ⅰ （good, no cortical perforation）, Grade Ⅱ （screw outside the pedicle 〈2 mm）, Grade Ⅲ （screw outside the pedicle 〉2 mm）. Results： In computer assisted group, 88 （95.65%） were Grade Ⅰ （good）, 4 （4.35%） were Grade Ⅱ （〈2mm）, no Grade Ⅲ （〉2 mm） violations. In conventional group, there were 14 cortical violations （16.67%）, 70 （83.33%） were Grade Ⅰ （good）, Ⅱ （13.1%） were Grade Ⅱ （〈2 mm）, and 3 （3,57%） were Grade Ⅲ （〉2 mm） violations （P〈0.001）. The number （19.57%） of upper thoracic pedicle screws （ T1-T4 ） inserted under 3D computer-assisted navigation was significantly higher than that （3.57%） by conventional fluoroscopic control （P〈0.001）. Average screw insertion time in conventional group was （4.56 ±1.03） min and （2.54 ± 0.63） min in computer assisted group （P〈0.001）. In the conventional group, one patient had pleura injury and one had a minor dura violation. Conclusions： This study provides further evidence that 3D computer-assisted navigation placement ofpedicle screws can increase accuracy, reduce surgical time, and be performed safely and effectively at all levels of the thoracic spine, particularly upper thoracic spine.
