Communication over wireless links identifies significant challenges for routing protocols operating. This paper proposes a Cross-layer design based Multipath Routing Protocol (CMRP) for mobile ad hoc networks, by mean...Communication over wireless links identifies significant challenges for routing protocols operating. This paper proposes a Cross-layer design based Multipath Routing Protocol (CMRP) for mobile ad hoc networks, by means of the node energy signal from the physical layer. The purpose is to optimize routing decision and path quality. The nodes’ mobility behavior is predicted using a notion of “Signal Fading Degree, SFD”. Especially, in combination of the IEEE 802.11e standard at the MAC layer, we determine that the IEEE 802.11e makes a significant contribution to performance improvement of CMRP. Performance evaluation of AODV in legacy 802.11 and CMRP in IEEE 802.11e shows that, as a function of speed of node mobility, a tremendous reduction achieved, in metrics such as the average end-to-end delay, route overhead, route discovery frequency, normalized routing load - almost more than 80%, 40%, 40%, and 40%. In the case of varying number of sessions, the reduction for route discovery frequency and normalized routing load are up to 70% and 80%.展开更多
Proton exchange membrane fuel cells(PEMFCs)have great potential to become the next generation green energy technique,but their application is limited by the slow kinetics of the cathode oxygen reduction reaction(ORR)i...Proton exchange membrane fuel cells(PEMFCs)have great potential to become the next generation green energy technique,but their application is limited by the slow kinetics of the cathode oxygen reduction reaction(ORR)in acidic medium.Meanwhile,the high price of Pt-based catalysts,which are now widely used commercially,has raised the cost of PEMFCs.Therefore,non-noble metal ORR catalysts as alternatives to Pt-based group metals(PGM)have attracted much attention.However,there is still a big gap between the performance of non-noble metal catalysts and commercial Pt/C catalysts in acidic environment.Recently,it has been realized that the performance of catalysts is closely related to the structure of catalytically active sites.Inspired by this,in this review,we firstly introduced the development and breakthrough of non-noble metals as activity sites.We then briefly summarized their catalytic mechanisms,and put forward some suggestions on how to improve the activity and stability of non-noble metal ORR catalysts.展开更多
文摘Communication over wireless links identifies significant challenges for routing protocols operating. This paper proposes a Cross-layer design based Multipath Routing Protocol (CMRP) for mobile ad hoc networks, by means of the node energy signal from the physical layer. The purpose is to optimize routing decision and path quality. The nodes’ mobility behavior is predicted using a notion of “Signal Fading Degree, SFD”. Especially, in combination of the IEEE 802.11e standard at the MAC layer, we determine that the IEEE 802.11e makes a significant contribution to performance improvement of CMRP. Performance evaluation of AODV in legacy 802.11 and CMRP in IEEE 802.11e shows that, as a function of speed of node mobility, a tremendous reduction achieved, in metrics such as the average end-to-end delay, route overhead, route discovery frequency, normalized routing load - almost more than 80%, 40%, 40%, and 40%. In the case of varying number of sessions, the reduction for route discovery frequency and normalized routing load are up to 70% and 80%.
基金The authors would like to thank the National Key R&D Program(2022YFB4004100)National Natural Science Foundation of China(21875243,21673221,22209168)+1 种基金Jilin Province Science and Technology Development Program(20200201001JC,20190201270JC,20180101030JC)Special Funds for Guiding Local Scientific,Technological Development by the Central Government(Grant No.2020JH6/10500021).
文摘Proton exchange membrane fuel cells(PEMFCs)have great potential to become the next generation green energy technique,but their application is limited by the slow kinetics of the cathode oxygen reduction reaction(ORR)in acidic medium.Meanwhile,the high price of Pt-based catalysts,which are now widely used commercially,has raised the cost of PEMFCs.Therefore,non-noble metal ORR catalysts as alternatives to Pt-based group metals(PGM)have attracted much attention.However,there is still a big gap between the performance of non-noble metal catalysts and commercial Pt/C catalysts in acidic environment.Recently,it has been realized that the performance of catalysts is closely related to the structure of catalytically active sites.Inspired by this,in this review,we firstly introduced the development and breakthrough of non-noble metals as activity sites.We then briefly summarized their catalytic mechanisms,and put forward some suggestions on how to improve the activity and stability of non-noble metal ORR catalysts.
