Ultrasound can be used as a carrier to realize wireless communication to and from a metal-enclosed space,which has the characteristics such as immunity to the electromagnetic shielding effect and non-destructive penet...Ultrasound can be used as a carrier to realize wireless communication to and from a metal-enclosed space,which has the characteristics such as immunity to the electromagnetic shielding effect and non-destructive penetration of metal obstacles.This paper firstly reviews the previous studies in the field of ultrasonic wireless communication through metal barriers,and summarizes their achievements and the existing problems.Secondly,an overview of the research methods involved in studying the characteristic of acoustic-electric channel is presented,and the principles are introduced for the actual measurement method,equivalent circuit method,ABCD parameter method,finite element analysis method and time-domain finite difference method.Then,an overview of the communication algorithms are presented such as orthogonal frequency division multiplexing(OFDM),single-carrier frequency domain equalization and multiple input multiple output OFDM.Finally,the potential future study are proposed in light of the trend of development and unsolved problems.展开更多
The incision of the Sanmen Gorge marks the birth of the modern Yellow River,but its timing varies from the late Miocene-early Pliocene to the late Pleistocene(~0.15 Ma),and the suggested forcing mechanisms vary from t...The incision of the Sanmen Gorge marks the birth of the modern Yellow River,but its timing varies from the late Miocene-early Pliocene to the late Pleistocene(~0.15 Ma),and the suggested forcing mechanisms vary from the uplift of the Tibetan Plateau to global climate change.Here,we report sedimentologic,geochronologic,and provenance data from a drill core near the Sanmen Gorge,the last gorge along the main course of the Yellow River.Our results indicate that typical river channel deposits,with detritus from the Ordos Block in the upstream regions,started to accumulate in the Sanmen Gorge at~1.25 Ma.When integrated with river terrace evidence from the upstream and downstream regions,the results provide robust evidence that the final integration of the modern Yellow River occurred at~1.25 Ma,consistent with the beginning of the Mid-Pleistocene transition(MPT).We propose that the accelerated lowering of eustatic sea level during the MPT may play as important a role as tectonism in driving the birth and evolution of the modern Yellow River.展开更多
基金the IACAS Young Elite Researcher Project QNYC201722。
文摘Ultrasound can be used as a carrier to realize wireless communication to and from a metal-enclosed space,which has the characteristics such as immunity to the electromagnetic shielding effect and non-destructive penetration of metal obstacles.This paper firstly reviews the previous studies in the field of ultrasonic wireless communication through metal barriers,and summarizes their achievements and the existing problems.Secondly,an overview of the research methods involved in studying the characteristic of acoustic-electric channel is presented,and the principles are introduced for the actual measurement method,equivalent circuit method,ABCD parameter method,finite element analysis method and time-domain finite difference method.Then,an overview of the communication algorithms are presented such as orthogonal frequency division multiplexing(OFDM),single-carrier frequency domain equalization and multiple input multiple output OFDM.Finally,the potential future study are proposed in light of the trend of development and unsolved problems.
基金supported by the Fundamental Research Funds for the Central Universities,China(lzujbky-2021-ey12)the National Natural Science Foundation of China(42072211)+1 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0602)the National Non-Profit Fundamental Research Grant of China(IGCEA 2008)。
文摘The incision of the Sanmen Gorge marks the birth of the modern Yellow River,but its timing varies from the late Miocene-early Pliocene to the late Pleistocene(~0.15 Ma),and the suggested forcing mechanisms vary from the uplift of the Tibetan Plateau to global climate change.Here,we report sedimentologic,geochronologic,and provenance data from a drill core near the Sanmen Gorge,the last gorge along the main course of the Yellow River.Our results indicate that typical river channel deposits,with detritus from the Ordos Block in the upstream regions,started to accumulate in the Sanmen Gorge at~1.25 Ma.When integrated with river terrace evidence from the upstream and downstream regions,the results provide robust evidence that the final integration of the modern Yellow River occurred at~1.25 Ma,consistent with the beginning of the Mid-Pleistocene transition(MPT).We propose that the accelerated lowering of eustatic sea level during the MPT may play as important a role as tectonism in driving the birth and evolution of the modern Yellow River.
