In the IoT(Internet of Things)system,the introduction of UAV(Unmanned Aerial Vehicle)as a new data collection platform can solve the problem that IoT devices are unable to transmit data over long distances due to the ...In the IoT(Internet of Things)system,the introduction of UAV(Unmanned Aerial Vehicle)as a new data collection platform can solve the problem that IoT devices are unable to transmit data over long distances due to the limitation of their battery energy.However,the unreasonable distribution of UAVs will still lead to the problem of the high total energy consumption of the system.In this work,to deal with the problem,a deployment model of a mobile edge computing(MEC)system based on multi-UAV is proposed.The goal of the model is to minimize the energy consumption of the system in the process of data transmission by optimizing the deployment of UAVs.The DEVIPSK(differential evolution algorithm with variable population size based on a mutation strategy pool initialized by K-Means)is proposed to solve the model.In DEVIPSK,the population is initialized by K-Means to obtain better initial positions of UAVs.Besides,considering the limitation of the fixed mutation strategy in the traditional evolutionary algorithm,a mutation strategy pool is used to update the positions of UAVs.The experimental results show the superiority of the DEVIPSK and provide guidance for the deployment of UAVs in the field of edge data collection in the IoT system.展开更多
The long-term stability issue of halide perovskite solar cells hinders their commercialization.The residual stress-strain affects device stability,which is derived from the mismatched thermophysical and mechanical pro...The long-term stability issue of halide perovskite solar cells hinders their commercialization.The residual stress-strain affects device stability,which is derived from the mismatched thermophysical and mechanical properties between adjacent layers.In this work,we introduced the Rb_(2)CO_(3)layer at the interface of SnO_(2)/perovskite with the hierarchy morphology of snowflake-like microislands and dendritic nanostructures.With a suitable thermal expansion coefficient,the Rb_(2)CO_(3)layer benefits the interfacial stress relaxation and results in a compressive stress-strain in the perovskite layer.Moreover,reduced nonradiative recombination losses and optimized band alignment were achieved.An enhancement of open-circuit voltage from 1.087 to 1.153 V in the resultant device was witnessed,which led to power conversion efficiency(PCE)of 22.7%(active area of 0.08313 cm^(2))and 20.6%(1 cm2).Moreover,these devices retained 95%of its initial PCE under the maximum power point tracking(MPPT)after 2700 h.It suggests inorganic materials with high thermal expansion coefficients and specific nanostructures are promising candidates to optimize interfacial mechanics,which improves the operational stability of perovskite cells.展开更多
Small molecule aptamers discovered by traditional selection methods usually lack conformational changes upon target binding.This limits the use of aptamers as molecular probes for small molecule detection and regulato...Small molecule aptamers discovered by traditional selection methods usually lack conformational changes upon target binding.This limits the use of aptamers as molecular probes for small molecule detection and regulatory elements of genetic circuits.Here,we report a new method called capture and in vitro transcription-systematic evolution of ligands by exponential enrichment(CIVT-SELEX)to select DNA aptamers that can not only bind to small molecule ligands but also undergo significant conformational changes.Through this method,we select a structure-switching aptamer of uridine-5′-diphosphate(UDP).Taking advantage of its conformational changes,we first construct a UDP-responsive transcriptional switch by inserting the aptamer in a genetic circuit and demonstrate that it can respond to the addition of UDP and regulate the transcription of downstream genes.We also build a UDP aptamer-based biosensor that can be used for active glycosyltransferase screening.We believe this method can provide a universal platform for selecting small molecule aptamers with conformational changes and expand the use of aptamers in small molecule detection and genetic regulation.展开更多
基金This paper was supported in part by Project funded by China Postdoctoral Science Foundation under Grant 2020M671552in part by Jiangsu Planned Projects for Postdoctoral Research Funds under Grant 2019K233+2 种基金in part by NUPTSF(NY220060)in part by the Opening Project of Jiangsu Key Laboratory of Data Science and Smart Software(No.2020DS301)in part by Natural Science Foundation of Jiangsu Province of China under Grant BK20191381.
文摘In the IoT(Internet of Things)system,the introduction of UAV(Unmanned Aerial Vehicle)as a new data collection platform can solve the problem that IoT devices are unable to transmit data over long distances due to the limitation of their battery energy.However,the unreasonable distribution of UAVs will still lead to the problem of the high total energy consumption of the system.In this work,to deal with the problem,a deployment model of a mobile edge computing(MEC)system based on multi-UAV is proposed.The goal of the model is to minimize the energy consumption of the system in the process of data transmission by optimizing the deployment of UAVs.The DEVIPSK(differential evolution algorithm with variable population size based on a mutation strategy pool initialized by K-Means)is proposed to solve the model.In DEVIPSK,the population is initialized by K-Means to obtain better initial positions of UAVs.Besides,considering the limitation of the fixed mutation strategy in the traditional evolutionary algorithm,a mutation strategy pool is used to update the positions of UAVs.The experimental results show the superiority of the DEVIPSK and provide guidance for the deployment of UAVs in the field of edge data collection in the IoT system.
基金National Natural Science Foundation of China,Grant/Award Numbers:52203323,U21A20172,21975028,52172182。
文摘The long-term stability issue of halide perovskite solar cells hinders their commercialization.The residual stress-strain affects device stability,which is derived from the mismatched thermophysical and mechanical properties between adjacent layers.In this work,we introduced the Rb_(2)CO_(3)layer at the interface of SnO_(2)/perovskite with the hierarchy morphology of snowflake-like microislands and dendritic nanostructures.With a suitable thermal expansion coefficient,the Rb_(2)CO_(3)layer benefits the interfacial stress relaxation and results in a compressive stress-strain in the perovskite layer.Moreover,reduced nonradiative recombination losses and optimized band alignment were achieved.An enhancement of open-circuit voltage from 1.087 to 1.153 V in the resultant device was witnessed,which led to power conversion efficiency(PCE)of 22.7%(active area of 0.08313 cm^(2))and 20.6%(1 cm2).Moreover,these devices retained 95%of its initial PCE under the maximum power point tracking(MPPT)after 2700 h.It suggests inorganic materials with high thermal expansion coefficients and specific nanostructures are promising candidates to optimize interfacial mechanics,which improves the operational stability of perovskite cells.
基金supported by the National Natural Science Foundation of China(32001037,22176035)the National Key R&D Program of China(2020YFA0210800,2018YFA0902600)+1 种基金the Natural Science Foundation of Fujian Province(2020J01491,2020J05120)Fuzhou University Research Fund(GXRC-20033)。
文摘Small molecule aptamers discovered by traditional selection methods usually lack conformational changes upon target binding.This limits the use of aptamers as molecular probes for small molecule detection and regulatory elements of genetic circuits.Here,we report a new method called capture and in vitro transcription-systematic evolution of ligands by exponential enrichment(CIVT-SELEX)to select DNA aptamers that can not only bind to small molecule ligands but also undergo significant conformational changes.Through this method,we select a structure-switching aptamer of uridine-5′-diphosphate(UDP).Taking advantage of its conformational changes,we first construct a UDP-responsive transcriptional switch by inserting the aptamer in a genetic circuit and demonstrate that it can respond to the addition of UDP and regulate the transcription of downstream genes.We also build a UDP aptamer-based biosensor that can be used for active glycosyltransferase screening.We believe this method can provide a universal platform for selecting small molecule aptamers with conformational changes and expand the use of aptamers in small molecule detection and genetic regulation.
