目的探讨双源CT对下肢动脉CT血管造影术(CT angiography,CTA)扫描方式的优化选择。方法使用双源CT对82例患者进下肢动脉CT造影扫描。按照随机数字表法分为A、B两组。A组30例患者扫描方式为感兴趣区(追踪层面)(region of interest,ROI)-...目的探讨双源CT对下肢动脉CT血管造影术(CT angiography,CTA)扫描方式的优化选择。方法使用双源CT对82例患者进下肢动脉CT造影扫描。按照随机数字表法分为A、B两组。A组30例患者扫描方式为感兴趣区(追踪层面)(region of interest,ROI)-腹主动脉下段(肾动脉横断面水平)作触发点,Bolus触发阈值150Hu。B组52例患者ROI选择在腘窝水平腘动脉处,Bolus触发阈值达100Hu后进行全程下肢扫描。造影剂用量、注射速率两组相同。结果经工作站重建后,A组30例中27例患者图像满足诊断要求,3例患者双下肢远端(足背侧及足尖)动脉显示不理想。B组52例病患动脉远端显示优良均达到临床诊断要求。结论合理选择ROI扫描方案是显示高质量下肢动脉图像的基础。展开更多
The zone control subsystem is a real-time control system,which requests the correctness of the control process.Train tracing scene is an important function of the zone controller(ZC)in the communication based train co...The zone control subsystem is a real-time control system,which requests the correctness of the control process.Train tracing scene is an important function of the zone controller(ZC)in the communication based train control(CBTC)system.In the process of deep development and design,to ensure the safety of the system,the system needs to be modeled,simulated and verified to discover the system design flaws.Unified modeling language(UML)is combined with timed automata,and timed automata network models of train-filter and train tracing demarcation-point are established.At the same time,the verification tool of UPPAAL is applied to simulate the system,and verify the requirements of performance and function of system.The results show that the function of train tracing demaraction-point meets the requirements of system safety and limited activity.Therefore,the method is feasible and can be applied to the modeling and verification of other scenes of train control system.展开更多
In the past few decades, economic globalization has driven rapid growth of cross-border trade and a new international division of labor, leading to increasing inter-country embodied carbon flows. Multi-region input-ou...In the past few decades, economic globalization has driven rapid growth of cross-border trade and a new international division of labor, leading to increasing inter-country embodied carbon flows. Multi-region input-output(MRIO) analysis is used to identify embodied carbon flows between major world regions, including seven regions along the Belt and Road(BR), and the spatial distribution of production-and consumption-based carbon intensities. The results show that current embodied carbon flows are virtually all from BR regions to developed countries, with more than 95% of world net embodied carbon exports coming from BR regions. Consumption in the United States and European Union countries induce about 30% of the carbon emissions in most BR regions, indicating that the former bear a high proportion of consumers' responsibility for the carbon emitted in the latter. For this reason, measuring environmental responsibilities from consumption rather than a production-based perspective is more equitable, while developing countries should be given a louder voice in the construction through dialogue and cooperation, in part in the context of the Belt and Road Initiative, of an inclusive global climate governance system.展开更多
文摘目的探讨双源CT对下肢动脉CT血管造影术(CT angiography,CTA)扫描方式的优化选择。方法使用双源CT对82例患者进下肢动脉CT造影扫描。按照随机数字表法分为A、B两组。A组30例患者扫描方式为感兴趣区(追踪层面)(region of interest,ROI)-腹主动脉下段(肾动脉横断面水平)作触发点,Bolus触发阈值150Hu。B组52例患者ROI选择在腘窝水平腘动脉处,Bolus触发阈值达100Hu后进行全程下肢扫描。造影剂用量、注射速率两组相同。结果经工作站重建后,A组30例中27例患者图像满足诊断要求,3例患者双下肢远端(足背侧及足尖)动脉显示不理想。B组52例病患动脉远端显示优良均达到临床诊断要求。结论合理选择ROI扫描方案是显示高质量下肢动脉图像的基础。
文摘The zone control subsystem is a real-time control system,which requests the correctness of the control process.Train tracing scene is an important function of the zone controller(ZC)in the communication based train control(CBTC)system.In the process of deep development and design,to ensure the safety of the system,the system needs to be modeled,simulated and verified to discover the system design flaws.Unified modeling language(UML)is combined with timed automata,and timed automata network models of train-filter and train tracing demarcation-point are established.At the same time,the verification tool of UPPAAL is applied to simulate the system,and verify the requirements of performance and function of system.The results show that the function of train tracing demaraction-point meets the requirements of system safety and limited activity.Therefore,the method is feasible and can be applied to the modeling and verification of other scenes of train control system.
基金National Key Research and Development Program of China,No.2016YFA0602804National Natural Science Foundation of China,No.41701135
文摘In the past few decades, economic globalization has driven rapid growth of cross-border trade and a new international division of labor, leading to increasing inter-country embodied carbon flows. Multi-region input-output(MRIO) analysis is used to identify embodied carbon flows between major world regions, including seven regions along the Belt and Road(BR), and the spatial distribution of production-and consumption-based carbon intensities. The results show that current embodied carbon flows are virtually all from BR regions to developed countries, with more than 95% of world net embodied carbon exports coming from BR regions. Consumption in the United States and European Union countries induce about 30% of the carbon emissions in most BR regions, indicating that the former bear a high proportion of consumers' responsibility for the carbon emitted in the latter. For this reason, measuring environmental responsibilities from consumption rather than a production-based perspective is more equitable, while developing countries should be given a louder voice in the construction through dialogue and cooperation, in part in the context of the Belt and Road Initiative, of an inclusive global climate governance system.
