针对多个物理层传输芯片(PHY)、单ATM层的应用情况,分析了Utop ia level 2接口时序,基于现场可编程门阵列(FPGA)设计并实现了轮询机制的Utop ia接口逻辑,给出了时序仿真结果。设计了一种ATM同高层协议的接口逻辑并给出了进一步减小轮询...针对多个物理层传输芯片(PHY)、单ATM层的应用情况,分析了Utop ia level 2接口时序,基于现场可编程门阵列(FPGA)设计并实现了轮询机制的Utop ia接口逻辑,给出了时序仿真结果。设计了一种ATM同高层协议的接口逻辑并给出了进一步减小轮询操作开销的方法。同传统单端口模式相比,节约了75%的逻辑资源和引脚。测试结果表明,4个物理层单元能以155 Mbps的速度双向并行通信,可为模块化设计提供参考。展开更多
Efficient control of the desulphurization system is challenging in maximizing the economic objective while reducing the SO_(2) emission concentration. The conventional optimization method is generally based on a hiera...Efficient control of the desulphurization system is challenging in maximizing the economic objective while reducing the SO_(2) emission concentration. The conventional optimization method is generally based on a hierarchical structure in which the upper optimization layer calculates the steady-state results and the lower control layer is responsible to drive the process to the target point. However, the conventional hierarchical structure does not take the economic performance of the dynamic tracking process into account. To this end, multi-objective economic model predictive control(MOEMPC) is introduced in this paper, which unifies the optimization and control layers in a single stage. The objective functions are formulated in terms of a dynamic horizon and to balance the stability and economic performance. In the MOEMPC scheme, economic performance and SO_(2) emission performance are guaranteed by tracking a set of utopia points during dynamic transitions. The terminal penalty function and stabilizing constraint conditions are designed to ensure the stability of the system. Finally, an optimized control method for the stable operation of the complex desulfurization system has been established. Simulation results demonstrate that MOEMPC is superior over another control strategy in terms of economic performance and emission reduction, especially when the desulphurization system suffers from frequent flue gas disturbances.展开更多
As one of the prominent landforms in the Zhurong landing region,mesas are geological features with flat tops and steep marginal cliffs.The mesas are widely distributed along the dichotomy boundary.There are various in...As one of the prominent landforms in the Zhurong landing region,mesas are geological features with flat tops and steep marginal cliffs.The mesas are widely distributed along the dichotomy boundary.There are various interpreted origins proposed for the mesas,such as the erosion of sedimentary layers,tuyas eruptions,or surface collapse due to the catastrophic release of groundwater.We investigate the detailed morphological characteristics of the mesas on the Late Hesperian Lowland unit within the Utopia Planitia.We observe morphological evidence for both the ice-bearing interior mesas and the sedimentary origin,including(1)small pits on the crater wall and mesa cliff formed by the release of volatiles like ice;(2)lobate flows at the base of mesas formed by the melting of subsurface ice;(3)layered mesas indicating sedimentary origin;(4)grooves on the top surface of mesas formed by the volumetric compaction of sedimentary deposits.The results indicate that the mesas in the study area are formed by the erosion of sedimentary layers and representative of the Noachian oceanic sediments.We propose an evolutionary model for the mesas.This study will provide some insights into future research of ancient ocean hypothesis of Mars and interesting targets for the exploration of the Zhurong rover.展开更多
基金supported by the National Key Research and Development Program of China (2017YFB0601805)。
文摘Efficient control of the desulphurization system is challenging in maximizing the economic objective while reducing the SO_(2) emission concentration. The conventional optimization method is generally based on a hierarchical structure in which the upper optimization layer calculates the steady-state results and the lower control layer is responsible to drive the process to the target point. However, the conventional hierarchical structure does not take the economic performance of the dynamic tracking process into account. To this end, multi-objective economic model predictive control(MOEMPC) is introduced in this paper, which unifies the optimization and control layers in a single stage. The objective functions are formulated in terms of a dynamic horizon and to balance the stability and economic performance. In the MOEMPC scheme, economic performance and SO_(2) emission performance are guaranteed by tracking a set of utopia points during dynamic transitions. The terminal penalty function and stabilizing constraint conditions are designed to ensure the stability of the system. Finally, an optimized control method for the stable operation of the complex desulfurization system has been established. Simulation results demonstrate that MOEMPC is superior over another control strategy in terms of economic performance and emission reduction, especially when the desulphurization system suffers from frequent flue gas disturbances.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 41000000)the National Natural Science Foundation of China(Nos.42273041,41830214)the Preresearch Project on Civil Aerospace Technologies of CNSA(No.D020101)。
文摘As one of the prominent landforms in the Zhurong landing region,mesas are geological features with flat tops and steep marginal cliffs.The mesas are widely distributed along the dichotomy boundary.There are various interpreted origins proposed for the mesas,such as the erosion of sedimentary layers,tuyas eruptions,or surface collapse due to the catastrophic release of groundwater.We investigate the detailed morphological characteristics of the mesas on the Late Hesperian Lowland unit within the Utopia Planitia.We observe morphological evidence for both the ice-bearing interior mesas and the sedimentary origin,including(1)small pits on the crater wall and mesa cliff formed by the release of volatiles like ice;(2)lobate flows at the base of mesas formed by the melting of subsurface ice;(3)layered mesas indicating sedimentary origin;(4)grooves on the top surface of mesas formed by the volumetric compaction of sedimentary deposits.The results indicate that the mesas in the study area are formed by the erosion of sedimentary layers and representative of the Noachian oceanic sediments.We propose an evolutionary model for the mesas.This study will provide some insights into future research of ancient ocean hypothesis of Mars and interesting targets for the exploration of the Zhurong rover.
