Ambient backscatter is a new green technology for Internet of Things(IoT)that utilizes surrounding wireless signals to enable batteryless devices to communicate with other devices.The battery-free devices first harves...Ambient backscatter is a new green technology for Internet of Things(IoT)that utilizes surrounding wireless signals to enable batteryless devices to communicate with other devices.The battery-free devices first harvest energy from ambient wireless signals and then backscatter the signals for communications.Clearly,sensitivity and distance are two important parameters for system performance.However,most existing studies on ambient backscatter communication systems do not consider the impact of the sensitivity of the energy-harvesting nodes and the distances between these devices.In this paper,we first provide a literature review for ambient communication technology and then take sensitivity and distance as two key parameters and investigate the sensitivity and distance based performance for ambient backscatter communication systems.Specifically,we establish the mathematical model based on distances between transceivers and backscattering nodes,extract a parameter that can differentiate the direct path and the backscattering path,evaluate the effects of transmit beamforming,design an energy detector for the reader,and analyze the outage probability of energy harvesting at the tag and the bit error rate(BER)at the reader.Simulations are then provided to corroborate the proposed studies.展开更多
Relying on direct and converse piezoelectric effects,piezo-acoustic backscatter(PAB)technology reflects ambient acoustic signals to enable underwater backscatter communications at near-zero power,which was first reali...Relying on direct and converse piezoelectric effects,piezo-acoustic backscatter(PAB)technology reflects ambient acoustic signals to enable underwater backscatter communications at near-zero power,which was first realized through a prototype.In this paper,we propose a mathematical model of the PAB assisted underwater acoustic(UWA)communication,and address the sparse channel estimation problem.First,we present a five-stage backscatter process to derive the backscatter coefficient,and propose the channel model for the shallow-water communications.Then,we formulate the shallow-water acoustic channel estimation problem as a sparse vector recovery one according to the compressed sensing theory,and leverage the orthogonal matching pursuit(OMP)algorithm to obtain the channel estimator.Finally,simulation results are provided to corroborate our proposed studies.展开更多
Tomato leaf curl New Delhi virus(ToLCNDV),a bipartite begomovirus,was first reported to infect tomato and has recently spread rapidly as an emerging disease to Cucurbitaceae crops.To date,the virus has been reported t...Tomato leaf curl New Delhi virus(ToLCNDV),a bipartite begomovirus,was first reported to infect tomato and has recently spread rapidly as an emerging disease to Cucurbitaceae crops.To date,the virus has been reported to infect more than 11 cucurbit crops,in 16 countries and regions,causing severe yield losses.In autumn 2022,ToLCNDV was first isolated from cucurbit plants in Southeastern coastal areas of China.Phylogenetic analysis established that these isolates belong to the Asian ToLCNDV clade,and shared high nucleotide identity and closest genetic relationship with the DNA-A sequence from the Chinese tomato-infecting ToLCNDV isolate(Accession no.OP356207)and the tomato New Delhi ToLCNDV-Severe isolate(Accession no.HM159454).In this review,we summarize the occurrence and distribution,host range,detection and diagnosis,control strategies,and genetic resistance of ToLCNDV in the Cucurbitaceae.We then summarize pathways that could be undertaken to improve our understanding of this emerging disease,with the objective to develop ToLCNDV-resistant cucurbit cultivars.展开更多
Main observation and conclusion The controllable achievement of C-C and C-P bond formations is developed via visible-light-promoted bromoalkyne dimerization or its further transformation with secondary phosphine oxide...Main observation and conclusion The controllable achievement of C-C and C-P bond formations is developed via visible-light-promoted bromoalkyne dimerization or its further transformation with secondary phosphine oxides.The 1,1-dibromo-1-en-3-ynes are formed when bromoalkyne is exposed to visible-light.While alkynylphosphine oxides are generated when bromoalkynes are mixed with secondary phosphine oxides.展开更多
基金supported by Scientific Research Program of Beijing Municipal Commission of Education(No.KM201910853003)National key research and development program(2020YFB1806604)Fundamental Research Funds for the Central Universities(No.2020YJS044).
文摘Ambient backscatter is a new green technology for Internet of Things(IoT)that utilizes surrounding wireless signals to enable batteryless devices to communicate with other devices.The battery-free devices first harvest energy from ambient wireless signals and then backscatter the signals for communications.Clearly,sensitivity and distance are two important parameters for system performance.However,most existing studies on ambient backscatter communication systems do not consider the impact of the sensitivity of the energy-harvesting nodes and the distances between these devices.In this paper,we first provide a literature review for ambient communication technology and then take sensitivity and distance as two key parameters and investigate the sensitivity and distance based performance for ambient backscatter communication systems.Specifically,we establish the mathematical model based on distances between transceivers and backscattering nodes,extract a parameter that can differentiate the direct path and the backscattering path,evaluate the effects of transmit beamforming,design an energy detector for the reader,and analyze the outage probability of energy harvesting at the tag and the bit error rate(BER)at the reader.Simulations are then provided to corroborate the proposed studies.
基金supported by National Key Research and Development Program of China(2020YFB1806604,2021YFB3901302)National Natural Science Foundation of China(No.61871026).
文摘Relying on direct and converse piezoelectric effects,piezo-acoustic backscatter(PAB)technology reflects ambient acoustic signals to enable underwater backscatter communications at near-zero power,which was first realized through a prototype.In this paper,we propose a mathematical model of the PAB assisted underwater acoustic(UWA)communication,and address the sparse channel estimation problem.First,we present a five-stage backscatter process to derive the backscatter coefficient,and propose the channel model for the shallow-water communications.Then,we formulate the shallow-water acoustic channel estimation problem as a sparse vector recovery one according to the compressed sensing theory,and leverage the orthogonal matching pursuit(OMP)algorithm to obtain the channel estimator.Finally,simulation results are provided to corroborate our proposed studies.
基金supported by a grant from the Key Research and Development Program of Hainan Province(ZDYF2021XDNY166)the Key Science and Technology Program for Agricultural(Vegetable)New Variety Breeding of Zhejiang Province(2021C02065)the Earmarked Fund for Modern Agro-Industry Technology Research System of China(CARS-26-17).
文摘Tomato leaf curl New Delhi virus(ToLCNDV),a bipartite begomovirus,was first reported to infect tomato and has recently spread rapidly as an emerging disease to Cucurbitaceae crops.To date,the virus has been reported to infect more than 11 cucurbit crops,in 16 countries and regions,causing severe yield losses.In autumn 2022,ToLCNDV was first isolated from cucurbit plants in Southeastern coastal areas of China.Phylogenetic analysis established that these isolates belong to the Asian ToLCNDV clade,and shared high nucleotide identity and closest genetic relationship with the DNA-A sequence from the Chinese tomato-infecting ToLCNDV isolate(Accession no.OP356207)and the tomato New Delhi ToLCNDV-Severe isolate(Accession no.HM159454).In this review,we summarize the occurrence and distribution,host range,detection and diagnosis,control strategies,and genetic resistance of ToLCNDV in the Cucurbitaceae.We then summarize pathways that could be undertaken to improve our understanding of this emerging disease,with the objective to develop ToLCNDV-resistant cucurbit cultivars.
基金We gratefully acknowledge the Natural Science Foundation of Educational Committee of Anhui Province(Nos.KJ2020A0045,KJ2020B01)the Scientific Research Project of Anhui Provincial Education Department(No.KJ2015TD002)for financial support of this work.
文摘Main observation and conclusion The controllable achievement of C-C and C-P bond formations is developed via visible-light-promoted bromoalkyne dimerization or its further transformation with secondary phosphine oxides.The 1,1-dibromo-1-en-3-ynes are formed when bromoalkyne is exposed to visible-light.While alkynylphosphine oxides are generated when bromoalkynes are mixed with secondary phosphine oxides.
