Limited by battery and computing re-sources,the computing-intensive tasks generated by Internet of Things(IoT)devices cannot be processed all by themselves.Mobile edge computing(MEC)is a suitable solution for this pro...Limited by battery and computing re-sources,the computing-intensive tasks generated by Internet of Things(IoT)devices cannot be processed all by themselves.Mobile edge computing(MEC)is a suitable solution for this problem,and the gener-ated tasks can be offloaded from IoT devices to MEC.In this paper,we study the problem of dynamic task offloading for digital twin-empowered MEC.Digital twin techniques are applied to provide information of environment and share the training data of agent de-ployed on IoT devices.We formulate the task offload-ing problem with the goal of maximizing the energy efficiency and the workload balance among the ESs.Then,we reformulate the problem as an MDP problem and design DRL-based energy efficient task offloading(DEETO)algorithm to solve it.Comparative experi-ments are carried out which show the superiority of our DEETO algorithm in improving energy efficiency and balancing the workload.展开更多
Noble-metal-free hydrogen/oxygen evolution reaction(HER/OER) electrocatalysts, especially bifunctional electrocatalysts, are essential for overall water splitting, but their performance is impeded by many factors like...Noble-metal-free hydrogen/oxygen evolution reaction(HER/OER) electrocatalysts, especially bifunctional electrocatalysts, are essential for overall water splitting, but their performance is impeded by many factors like poor electrical conductivity. Herein, we fabricated cobalt phosphide(Co P) nanoparticles embedded in P and N co-doped carbon(PNC) matrix(Co P@PNC) to fully realize the high activity of Co P by maximizing its conductivity. Simply a carbonization coupled phosphidation approach was utilized where Co ions and organic ligands of Co-MOF were transferred into Co P and P and N co-doped carbon. The synthesized material shows an ideal electrical conductivity, excellent HER(overpotential of-84 m V and-120 m V @10 m A cm^(-2) in acidic and alkaline medias, respectively) and OER(overpotential of 330 m V@10 m A cm^(-2) in alkaline media) performances. Further, Co P@PNC acts as a superior catalyst for both anode and cathode to catalyze overall water splitting and only requires an voltage of 1.52 V to deliver a current density of 10 m A cm^(-2), superior to the noble-metal catalysts system(Pt/C//IrO_2) and the reported noble-metal-free bifunctional electrocatalysts.展开更多
As a starting point in equipment manufacturing,sawing plays an important role in industrial production.Intelligent manufacturing equipment is an important carrier of intelligent manufacturing technologies.Due to the b...As a starting point in equipment manufacturing,sawing plays an important role in industrial production.Intelligent manufacturing equipment is an important carrier of intelligent manufacturing technologies.Due to the backwardness of intelligent technology,the comprehensive performance of sawing equipments in China is obviously different from that in foreign countries.State of the art of advanced sawing equipments is investigated along with the technical bottleneck of sawing machine tool manufacturing,and a new industrial scheme of replacing turning-milling by sawing is described.The key technologies of processing-measuring integrated control,multi-body dynamic optimization,the collaborative sawing network framework,the distributed cloud sawing platform,and the self-adapting service method are analyzed;with consideration of the problems of poor processing control stableness,low single machine intelligence level,no on-line processing data service and active flutter suppression of sawing with wide-width and heavy-load working conditions.Suggested directions for further research,industry implementation,and industry-research collaboration are provided.展开更多
We systematically study the low-temperature specific heats for the two-dimensional kagome antiferromagnet,Cu_(3)Zn(OH)_(6)FBr.The specific heat exhibits a T1.7 dependence at low temperatures and a shoulder-like featur...We systematically study the low-temperature specific heats for the two-dimensional kagome antiferromagnet,Cu_(3)Zn(OH)_(6)FBr.The specific heat exhibits a T1.7 dependence at low temperatures and a shoulder-like feature above it.We construct a microscopic lattice model of Z_(2) quantum spin liquid and perform large-scale quantum Monte Carlo simulations to show that the above behaviors come from the contributions from gapped anyons and magnetic impurities.Surprisingly,we find the entropy associated with the shoulder decreases quickly with grain size d,although the system is paramagnetic to the lowest temperature.While this can be simply explained by a core-shell picture in that the contribution from the interior state disappears near the surface,the 5.9-nm shell width precludes any trivial explanations.Such a large length scale signifies the coherence length of the nonlocality of the quantum entangled excitations in quantum spin liquid candidate,similar to Pippard’s coherence length in superconductors.Our approach therefore offers a new experimental probe of the intangible quantum state of matter with topological order.展开更多
Noxious mechanical information is transmitted through molecularly distinct nociceptors,with pinprickevoked sharp sensitivity via A-fiber nociceptors marked by developmental expression of the neuropeptide Y receptor 2(...Noxious mechanical information is transmitted through molecularly distinct nociceptors,with pinprickevoked sharp sensitivity via A-fiber nociceptors marked by developmental expression of the neuropeptide Y receptor 2(Npy2 r)and von Frey filament-evoked punctate pressure information via unmyelinated C fiber nociceptors marked by MrgprD.However,the molecular programs controlling their development are only beginning to be understood.Here we demonstrate that Npy2 r-expressing sensory neurons are in fact divided into two groups,based on transient or persistent Npy2 r expression.Npy2 r-transient neurons are myelinated,likely including A-fiber nociceptors,whereas Npy2 r-persistent ones belong to unmyelinated pruriceptors that co-express Nppb.We then showed that the transcription factors NFIA and Runx1 are necessary for the development of Npy2 r-transient A-fiber nociceptors and MrgprD^+C-fiber nociceptors,respectively.Behaviorally,mice with conditional knockout of Nfia,but not Runx1 showed a marked attenuation of pinprick-evoked nocifensive responses.Our studies therefore identify a transcription factor controlling the development of myelinated nociceptors.展开更多
基金This work was partly supported by the Project of Cultivation for young top-motch Talents of Beijing Municipal Institutions(No BPHR202203225)the Young Elite Scientists Sponsorship Program by BAST(BYESS2023031)the National key research and development program(No 2022YFF0604502).
文摘Limited by battery and computing re-sources,the computing-intensive tasks generated by Internet of Things(IoT)devices cannot be processed all by themselves.Mobile edge computing(MEC)is a suitable solution for this problem,and the gener-ated tasks can be offloaded from IoT devices to MEC.In this paper,we study the problem of dynamic task offloading for digital twin-empowered MEC.Digital twin techniques are applied to provide information of environment and share the training data of agent de-ployed on IoT devices.We formulate the task offload-ing problem with the goal of maximizing the energy efficiency and the workload balance among the ESs.Then,we reformulate the problem as an MDP problem and design DRL-based energy efficient task offloading(DEETO)algorithm to solve it.Comparative experi-ments are carried out which show the superiority of our DEETO algorithm in improving energy efficiency and balancing the workload.
基金support from the National Natural Science Foundation of China(51661145026,21676193,21506156)the Tianjin Municipal Natural Science Foundation(15JCZDJC37300)
文摘Noble-metal-free hydrogen/oxygen evolution reaction(HER/OER) electrocatalysts, especially bifunctional electrocatalysts, are essential for overall water splitting, but their performance is impeded by many factors like poor electrical conductivity. Herein, we fabricated cobalt phosphide(Co P) nanoparticles embedded in P and N co-doped carbon(PNC) matrix(Co P@PNC) to fully realize the high activity of Co P by maximizing its conductivity. Simply a carbonization coupled phosphidation approach was utilized where Co ions and organic ligands of Co-MOF were transferred into Co P and P and N co-doped carbon. The synthesized material shows an ideal electrical conductivity, excellent HER(overpotential of-84 m V and-120 m V @10 m A cm^(-2) in acidic and alkaline medias, respectively) and OER(overpotential of 330 m V@10 m A cm^(-2) in alkaline media) performances. Further, Co P@PNC acts as a superior catalyst for both anode and cathode to catalyze overall water splitting and only requires an voltage of 1.52 V to deliver a current density of 10 m A cm^(-2), superior to the noble-metal catalysts system(Pt/C//IrO_2) and the reported noble-metal-free bifunctional electrocatalysts.
基金Supported by Natural Science Foundation of China(Grant No.51775501)Natural Science Foundation of Zhejiang Province,China(Grant Nos.LZ21E050003,LR16E050001,LY17E050004).
文摘As a starting point in equipment manufacturing,sawing plays an important role in industrial production.Intelligent manufacturing equipment is an important carrier of intelligent manufacturing technologies.Due to the backwardness of intelligent technology,the comprehensive performance of sawing equipments in China is obviously different from that in foreign countries.State of the art of advanced sawing equipments is investigated along with the technical bottleneck of sawing machine tool manufacturing,and a new industrial scheme of replacing turning-milling by sawing is described.The key technologies of processing-measuring integrated control,multi-body dynamic optimization,the collaborative sawing network framework,the distributed cloud sawing platform,and the self-adapting service method are analyzed;with consideration of the problems of poor processing control stableness,low single machine intelligence level,no on-line processing data service and active flutter suppression of sawing with wide-width and heavy-load working conditions.Suggested directions for further research,industry implementation,and industry-research collaboration are provided.
基金Supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0302900,2016YFA0300500,and2020YFA0406003)the National Natural Science Foundation of China(Grant Nos.11874401,11674406,11961160699,11774399+4 种基金11804383)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant Nos.XDB33000000,XDB28000000,XDB25000000XDB07020000)the K.C.Wong Education Foundation(Grant Nos.GJTD-2020-01 and GJTD-2018-01)the Beijing Natural Science Foundation(Grant No.Z180008)。
文摘We systematically study the low-temperature specific heats for the two-dimensional kagome antiferromagnet,Cu_(3)Zn(OH)_(6)FBr.The specific heat exhibits a T1.7 dependence at low temperatures and a shoulder-like feature above it.We construct a microscopic lattice model of Z_(2) quantum spin liquid and perform large-scale quantum Monte Carlo simulations to show that the above behaviors come from the contributions from gapped anyons and magnetic impurities.Surprisingly,we find the entropy associated with the shoulder decreases quickly with grain size d,although the system is paramagnetic to the lowest temperature.While this can be simply explained by a core-shell picture in that the contribution from the interior state disappears near the surface,the 5.9-nm shell width precludes any trivial explanations.Such a large length scale signifies the coherence length of the nonlocality of the quantum entangled excitations in quantum spin liquid candidate,similar to Pippard’s coherence length in superconductors.Our approach therefore offers a new experimental probe of the intangible quantum state of matter with topological order.
基金supported by the National Natural Science Foundation of China (31771621,31171071 and 31671093)the Research Foundation for Advanced Talents from Hangzhou Normal University and the New York State Stem Cell Science contracts C026429 and C030133。
文摘Noxious mechanical information is transmitted through molecularly distinct nociceptors,with pinprickevoked sharp sensitivity via A-fiber nociceptors marked by developmental expression of the neuropeptide Y receptor 2(Npy2 r)and von Frey filament-evoked punctate pressure information via unmyelinated C fiber nociceptors marked by MrgprD.However,the molecular programs controlling their development are only beginning to be understood.Here we demonstrate that Npy2 r-expressing sensory neurons are in fact divided into two groups,based on transient or persistent Npy2 r expression.Npy2 r-transient neurons are myelinated,likely including A-fiber nociceptors,whereas Npy2 r-persistent ones belong to unmyelinated pruriceptors that co-express Nppb.We then showed that the transcription factors NFIA and Runx1 are necessary for the development of Npy2 r-transient A-fiber nociceptors and MrgprD^+C-fiber nociceptors,respectively.Behaviorally,mice with conditional knockout of Nfia,but not Runx1 showed a marked attenuation of pinprick-evoked nocifensive responses.Our studies therefore identify a transcription factor controlling the development of myelinated nociceptors.
