The radio frequency(RF)fingerprint technique is a robust method for security enhancement of the physical layer by leveraging the unique RF imperfections inherent in various wireless devices.Among these imperfections,t...The radio frequency(RF)fingerprint technique is a robust method for security enhancement of the physical layer by leveraging the unique RF imperfections inherent in various wireless devices.Among these imperfections,the carrier frequency offset(CFO)stands out as a primary RF fingerprint(RFF)of the transmitter,offering the potential to distinguish among different transmitters.However,accurately estimating CFO in time-varying channels poses significant challenges due to multipath effects and Doppler shifts.In this paper,we focus on estimating CFO for wireless device identification in the orthogonal frequency division multiplexing(OFDM)communication system.To achieve precise CFO estimation under time-varying channels,we propose a frequency domain correlation and spline interpolation(FCSI)algorithm.This approach utilizes pilots distributed across different subcarriers to correlate with prior local sequences,facilitating accurate CFO estimation.Classification is then performed based on the Euclidean distance between the prior RFF and the tested RFF dataset.Simulation results demonstrate that the proposed Mconsecutive average method effectively reduces the classification error rate in the challenging high-frequency(HF)skywave channel environment.展开更多
Photocatalysis uses solar energy to convert nitrogen and water directly into ammonia,helping reduce dependence on fossil fuels and offering a way to integrate the nitrogen cycle into a clean energy network.Ohmic junct...Photocatalysis uses solar energy to convert nitrogen and water directly into ammonia,helping reduce dependence on fossil fuels and offering a way to integrate the nitrogen cycle into a clean energy network.Ohmic junctions between metals and semiconductors have demonstrated significant advantages in enhancing stability and reducing carrier recombination,but their application in photocatalytic nitrogen fixation is limited due to the difficulty of work function matching and the complexity of fabrication processes.In this study,density functional theory(DFT) calculations were used to confirm the work function matching between Bi and Bi_(2)Ti_(2)O_(7)(BTO),ensuring the formation of an Ohmic junction.A Bi-Bi_(2)Ti_(2)O_(7)(B-BTO) composite was successfully synthesized via a one-step hydrothermal method,using bismuth nitrate and titanium sulfate as precursors.Compared to pure BTO,the B-BTO heterojunction,driven by dual electron injection from both metal Bi and BTO,significantly increased the ammonia synthesis rate to 686.95 μmol g^(-1)h^(-1),making it the most active nitrogen fixation material among similar pyrochlorebased catalysts to date.The differential charge density calculations,photocurrent(i-t) measurements,and photoluminescence(PL) tests further validate the role of Ohmic contacts in enhancing charge transfer and prolonging carrier lifetimes.This research provides valuable insight into the application of Ohmic junctions in photocatalytic nitrogen fixation and contributes to advancements in this field.展开更多
Turbulent flow over gravel beds in open channels is a fundamental yet complex problem in hydraulic engineering,as flow behavior is highly sensitive to channel geometry and bed roughness.In this study,the Volume of Flu...Turbulent flow over gravel beds in open channels is a fundamental yet complex problem in hydraulic engineering,as flow behavior is highly sensitive to channel geometry and bed roughness.In this study,the Volume of Fluid(VOF)method coupled with the standard k-εturbulence model is employed to simulate air-water interactions over gravel beds,with open boundary conditions capturing realistic channel-atmosphere interactions.Numerical simulations are performed to examine how channel design influences the relationship between the friction factor(f)and the Reynolds number(RN).Velocity and VOF contours indicate peak flow near the inlet,with a maximum velocity of 0.64 m/s.The simulations show strong agreement with theoretical predictions,yielding a correlation coefficient of 0.99 for RN,while f and Chezy’s coefficient(C)reach 0.75 and 0.71,respectively.Comparison with experimental measurements shows deviations of approximately 17% for RN,25% for f,and 12% for C.Moreover,further analysis confirms an inverse linear relationship between f and RN,in accordance with classical models such as Bazin’s curves,the Colebrook equation,and Moody’s approximation.Overall,the results demonstrate that the proposed numerical framework reliably captures flow dynamics over gravel beds,offering a robust tool for hydraulic design and performance assessment of open channels.展开更多
The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central n...The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.展开更多
Constructing silicon(Si)-based composite electrodes that possess high energy density,long cycle life,and fast charging capability simultaneously is critical for the development of high performance lithium-ion batterie...Constructing silicon(Si)-based composite electrodes that possess high energy density,long cycle life,and fast charging capability simultaneously is critical for the development of high performance lithium-ion batteries for mitigating range anxiety and slow charging issues in new energy vehicles.Herein,a thick silicon/carbon composite electrode with vertically aligned channels in the thickness direction(VC-SC)is constructed by employing a bubble formation method.Both experimental characterizations and theoretical simulations confirm that the obtained vertical channel structure can effectively address the problem of sluggish ion transport caused by high tortuosity in conventional thick electrodes,conspicuously enhance reaction kinetics,reduce polarization and side reactions,mitigate stress,increase the utilization of active materials,and promote cycling stability of the thick electrode.Consequently,when paired with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622),the VC-SC||NCM622 pouch type full cell(~6.0 mAh cm^(-2))exhibits significantly improved rate performance and capacity retention compared with the SC||NCM622 full cell with the conventional silicon/carbon composite electrode without channels(SC)as the anode.The assembled VC-SC||NCM622 pouch full cell with a high energy density of 490.3 Wh kg^(-1)also reveals a remarkable fast charging capability at a high current density of 2.0 mA cm^(-2),with a capacity retention of 72.0%after 500 cycles.展开更多
This study numerically examines the heat and mass transfer characteristics of two ternary nanofluids via converging and diverg-ing channels.Furthermore,the study aims to assess two ternary nanofluids combinations to d...This study numerically examines the heat and mass transfer characteristics of two ternary nanofluids via converging and diverg-ing channels.Furthermore,the study aims to assess two ternary nanofluids combinations to determine which configuration can provide better heat and mass transfer and lower entropy production,while ensuring cost efficiency.This work bridges the gap be-tween academic research and industrial feasibility by incorporating cost analysis,entropy generation,and thermal efficiency.To compare the velocity,temperature,and concentration profiles,we examine two ternary nanofluids,i.e.,TiO_(2)+SiO_(2)+Al_(2)O_(3)/H_(2)O and TiO_(2)+SiO_(2)+Cu/H_(2)O,while considering the shape of nanoparticles.The velocity slip and Soret/Dufour effects are taken into consideration.Furthermore,regression analysis for Nusselt and Sherwood numbers of the model is carried out.The Runge-Kutta fourth-order method with shooting technique is employed to acquire the numerical solution of the governed system of ordinary differential equations.The flow pattern attributes of ternary nanofluids are meticulously examined and simulated with the fluc-tuation of flow-dominating parameters.Additionally,the influence of these parameters is demonstrated in the flow,temperature,and concentration fields.For variation in Eckert and Dufour numbers,TiO_(2)+SiO_(2)+Al_(2)O_(3)/H_(2)O has a higher temperature than TiO_(2)+SiO_(2)+Cu/H_(2)O.The results obtained indicate that the ternary nanofluid TiO_(2)+SiO_(2)+Al_(2)O_(3)/H_(2)O has a higher heat transfer rate,lesser entropy generation,greater mass transfer rate,and lower cost than that of TiO_(2)+SiO_(2)+Cu/H_(2)O ternary nanofluid.展开更多
The study of stretching surfaces has garnered significant attention due to its importance in a wide range of industrial and engineering functions,including the drawing of wires and plastic films,shrink film production...The study of stretching surfaces has garnered significant attention due to its importance in a wide range of industrial and engineering functions,including the drawing of wires and plastic films,shrink film production,polymer sheet extrusion,the manufacturing of glass fibers,and the manufacturing of polyester heat-shrink tubing.This research incorporates a Darcy-Forchheimer porous medium to account for the effects of porosity.The governing equations are transformed into a boundary value problem and solved semi-analytically using the Taylor wavelet method.The effects of various parameters are depicted through graphical analyses.The results show that for both converging and diverging stretching surfaces,an increase in the porosity parameter causes a decrease in the velocity field.Additionally,higher Reynolds numbers enhance inertial effects,leading to more pronounced velocity fluctuations.Stretching causes a consistent drop in velocity toward the center and an increase close to the walls in both types of channels,indicating that the volume percentage of nanoparticles influences the heat distribution.Notably,stretching induces a marked temperature drop at the channel's center.展开更多
Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thal...Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.展开更多
Taihu Snow (838262) is a home textile manufacturing company listed on the Beijing Stock Exchange in 2022.It is a bedding manufacturer focusing on silk products.The company was esta blished on May 18,2006,Centered arou...Taihu Snow (838262) is a home textile manufacturing company listed on the Beijing Stock Exchange in 2022.It is a bedding manufacturer focusing on silk products.The company was esta blished on May 18,2006,Centered around the"Taihu Snow"brand,its products cover suite products (such as pillowcases,quilt covers,sheets),quilt cores,silk scarves and otheremerging retail products.展开更多
Type 2 diabetes mellitus(T2DM)is a prevalent metabolic disorder.Despite the availability of numerous pharmacotherapies,a range of adverse reactions,including hypoglycemia,gastrointestinal discomfort,and lactic acidosi...Type 2 diabetes mellitus(T2DM)is a prevalent metabolic disorder.Despite the availability of numerous pharmacotherapies,a range of adverse reactions,including hypoglycemia,gastrointestinal discomfort,and lactic acidosis,limits their patient applicability and long-term application.Therefore,it is necessary to screen novel therapeutic drugs for T2DM treatment that have high efficacy but few adverse effects.AMP-activated protein kinase(AMPK)stands out as one of the most powerful targets for T2DM treatment.It can be activated through energysensing or calcium signaling.Medications that activate AMPK through the energy-sensing mechanism exhibit remarkable potency,but they are accompanied by lactic acidosis,carrying an alarmingly high mortality rate.Interestingly,medications that activate AMPK through calcium signaling,such as gliclazide,seldom induce lactic acidosis.However,the efficacy of gliclazide is much lower than metformin.Therefore,it is necessary to explore targets that activate AMPK via calcium signaling to avoid lactic acidosis while maintaining high potency.Ion channels are the main controller of intracellular calcium flow.Specific agonists and inhibitors targeting ion channels have been reported to activate AMPK.In this review,we will summarize the structure and function of calcium-permeable ion channels and discuss the potential of targeting these calcium channels for T2DM treatment.展开更多
Accurate non-line of sight(NLOS)identification technique in ultra-wideband(UWB)location-based services is critical for applications like drone communication and autonomous navigation.However,current methods using bina...Accurate non-line of sight(NLOS)identification technique in ultra-wideband(UWB)location-based services is critical for applications like drone communication and autonomous navigation.However,current methods using binary classification(LOS/NLOS)oversimplify real-world complexities,with limited generalisation and adaptability to varying indoor environments,thereby reducing the accuracy of positioning.This study proposes an extreme gradient boosting(XGBoost)model to identify multi-class NLOS conditions.We optimise the model using grid search and genetic algorithms.Initially,the grid search approach is used to identify the most favourable values for integer hyperparameters.In order to achieve an optimised model configuration,the genetic algorithm is employed to fine-tune the floating-point hyperparameters.The model evaluations utilise a wide-ranging dataset of real-world measurements obtained with a Qorvo DW1000 UWB device,covering various indoor scenarios.Experimental results show that our proposed XGBoost achieved the highest overall accuracy of 99.47%,precision of 99%,recall of 99%,and an F-score of 99%on an open-source dataset.Additionally,based on a local dataset,the model achieved the highest performance,with an accuracy of 96%,precision of 96%,recall of 97%,and an F-score of 97%.In contrast to current machine learning methods in the literature,the suggestion model enhances classification accuracy and effectively addresses the NLOS/LOS identification as a multiclass propagation channel.This approach provides a robust solution with generalisation and adaptability across various dataset types and environments for more reliable and accurate indoor positioning technologies.展开更多
The huge carrier transfer resistance caused by large-sized"nitrogen pot"severely limits the photocatalytic performance of carbon nitride(CN).This study aims to explore the selection principle of metal ion br...The huge carrier transfer resistance caused by large-sized"nitrogen pot"severely limits the photocatalytic performance of carbon nitride(CN).This study aims to explore the selection principle of metal ion bridges for constructing dual carrier-transfer channels to delivery carriers to respectively active sites using photodegradation of phenol as the model reaction.Density functional theory(DFT)calculation was used to optimize the structure model of nitrogen vacancies(Nv,provide active sites for reduction of O_(2) and oxidation of phenol)and metal ions(Fe^(3+),Co^(2+),Ni^(2+)or Cu^(2+))co-modified CN,and screen metal ion bridges based on the three parameters including bonding state of metal ion and"nitrogen pot",electrostatic potential(ESP)distribution around the active sites,and three-electron bond length.Both calculation results and activity data show that Fe^(3+),Co^(2+)and Ni^(2+)can construct dual carrier-transfer channels to promote the degradation of phenol while Cu^(2+)cannot Ny and Fe^(3+)co-modified CN(Fe/N_(v)-CN)showed the best catalytic performance among various catalysts and was used as the model catalyst for the detailed characterization to verify the calculation results.This work provides not only the novel strategy for constructing dual carrier-transfer channels in CN,but also the crucial basis for computer simulation as a prediction tool of catalyst structure design rationality.展开更多
The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for es...The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for estimating SMSQ_DFC do not consider the capacity of the channel cross-section to accommodate sediment materials.This accommodation condition serves as a limiting factor in determining whether the expected surplus of sediment materials can ultimately be stored.To address this issue,a mass-conservative index was used to represent the balance of deposit materials at any cross-section,considering the influx from upstream,outflux to downstream,and accommodation capacity.Based on this index,a new model for estimating SMSQ_DFC was developed and subsequently evaluated.The evaluation results show that the model meets the accuracy requirements with average error rates of 14.06%for self-validation and 14.81%for generalization ability validation.To assess its practical applications,the model was applied to the Yeniu Gully in Wenchuan County,Sichuan Province,an area with detailed field survey data.The results show that the model exhibits a commendable performance.Compared to traditional theoretical and semi-theoretical statistical models,our model is easier to use(input parameters can be obtained using Geographic Information Systems(GIS)).The modeling parameters chosen in this study have more theoretical significance than those used in existing purely statistical models,offering more effective technical support for estimating SMSQ_DFC.展开更多
Reliable channel data helps characterize the limitations and performance boundaries of communication technologies accurately.However,channel measurement is highly costly and time-consuming,and taking actual measuremen...Reliable channel data helps characterize the limitations and performance boundaries of communication technologies accurately.However,channel measurement is highly costly and time-consuming,and taking actual measurement as the only channel data source may reduce efficiency because of the constraints of high testing difficulty and limited data volume.Although existing standard channel models can generate channel data,their authenticity and diversity cannot be guaranteed.To address this,we use deep learning methods to learn the attributes of limited measured data and propose a generative model based on generative adversarial networks to rapidly synthesize data.A software simulation platform is also established to verify that the proposed model can generate data that are statistically similar to the measured data while maintaining necessary randomness.The proposed algorithm and platform can be applied to channel data enhancement and serve channel modeling and algorithm evaluation applications with urgent needs for data.展开更多
Covert communication guarantees the security of wireless communications via hiding the existence of the transmission.This paper focuses on the first and second order asymptotics of covert communication in the AWGN cha...Covert communication guarantees the security of wireless communications via hiding the existence of the transmission.This paper focuses on the first and second order asymptotics of covert communication in the AWGN channels.The covertness is measured by the total variation distance between the channel output distributions induced with and without the transmission.We provide the exact expressions of the maximum amount of information that can be transmitted with the maximum error probability and the total variation less than any small numbers.The energy detection and the random coding are employed to prove our results.We further compare our results with those under relative entropy.The results show how many additional amounts of information can be transmitted covertly when changing the covertness constraint to total variation.展开更多
Aqueous zinc-ion batteries(ZIBs)are promising candidates for next-generation energy storage,but the problems related to Zn dendrites and side reactions severely hinder their practical applications.Herein,a self-recogn...Aqueous zinc-ion batteries(ZIBs)are promising candidates for next-generation energy storage,but the problems related to Zn dendrites and side reactions severely hinder their practical applications.Herein,a self-recognition separator based on a Bi-based metal-organic framework(GF@CAU-17)is developed for ion management to achieve highly reversible Zn anodes.The GF@CAU-17 has self-recognition behavior to customize selective Zn^(2+)channels,effectively repelling SO_(4)^(2-)and H_(2)O,but facilitating Zn^(2+)conduction.The inherent properties of CAU-17 result in the repulsion of SO_(4)^(2-)ions while disrupting the hydrogen bond network among free H_(2)O molecules,restraining side reactions and by-products.Simultaneously,the zincophilic characteristic of CAU-17 expedites the desolvation of[Zn(H_(2)O)6]^(2+),leading to a self-expedited Zn^(2+)ion pumping effect that dynamically produces a steady and homogeneous Zn^(2+)ion flux,and thereby alleviates concentration polarization.Consequently,a symmetric cell based on the GF@CAU-17 separator can achieve a long lifespan of 4450 h.Moreover,the constructed Zn//GF@CAU-17//MnO_(2)cell delivers a high specific capacity of 221.8 mAh g^(-1)and 88.0%capacity retention after 2000 cycles.展开更多
To improve the decoding performance of quantum error-correcting codes in asymmetric noise channels,a neural network-based decoding algorithm for bias-tailored quantum codes is proposed.The algorithm consists of a bias...To improve the decoding performance of quantum error-correcting codes in asymmetric noise channels,a neural network-based decoding algorithm for bias-tailored quantum codes is proposed.The algorithm consists of a biased noise model,a neural belief propagation decoder,a convolutional optimization layer,and a multi-objective loss function.The biased noise model simulates asymmetric error generation,providing a training dataset for decoding.The neural network,leveraging dynamic weight learning and a multi-objective loss function,mitigates error degeneracy.Additionally,the convolutional optimization layer enhances early-stage convergence efficiency.Numerical results show that for bias-tailored quantum codes,our decoder performs much better than the belief propagation(BP)with ordered statistics decoding(BP+OSD).Our decoder achieves an order of magnitude improvement in the error suppression compared to higher-order BP+OSD.Furthermore,the decoding threshold of our decoder for surface codes reaches a high threshold of 20%.展开更多
In this paper,we investigate the performance of physical layer security(PLS)over reconfigurable intelligent surfaces(RIS)-aided wireless communication systems,where all fading channels are modeled with Fisher-Snedecor...In this paper,we investigate the performance of physical layer security(PLS)over reconfigurable intelligent surfaces(RIS)-aided wireless communication systems,where all fading channels are modeled with Fisher-Snedecor F distribution.Specifically,we consider a RIS with N reflecting elements between the transmitter and the legitimate receiver to develop a smart environment and also meliorate secure communications.In this regard,we derive the closed-form expressions for the secrecy outage probability(SOP)and average secrecy capacity(ASC).We also analyze the asymptotic behaviour of the SOP and ASC by exploiting the residue approach.Monte-Carlo(MC)simulation results are provided throughout to validate the correctness of the developed analytical results,showing that considering RIS in wireless communication systems has constructive effects on the secrecy performance.展开更多
We propose a photon-photon collider based on synchrotron gamma sources driven by relativistic electron beams in hollow plasma channels.The collimated(with a divergence angle of~1 mrad)and ultrabrilliant(>10^(28)pho...We propose a photon-photon collider based on synchrotron gamma sources driven by relativistic electron beams in hollow plasma channels.The collimated(with a divergence angle of~1 mrad)and ultrabrilliant(>10^(28)photons s^(-1)·mrad^(-2)·mm^(-2)per 0.1% bandwidth at 0.6 MeV)photon beams are generated by strong electromagnetic fields induced by current filamentation instability,and up to~10^(6) Breit-Wheeler(BW)pairs can be created per shot.Notably,the usage of hollow plasma channels not only enhances synchrotron radiation,but also allows flexible control of the produced photon beams,ensuring the alignment of the two colliding beams and maximizing the two-photon BW process.This setup has the advantage of a clean background by eliminating the yield from the nonlinear BW process,and the signal-to-noise ratio is higher than 10^(2).展开更多
基金supported by ZTE Industry-University-Institute Cooperation Funds under Grant No.IA20240723011National Natural Science Foundation of China under Grant No.62371123+1 种基金Young Elite Scientists Sponsorship Program of the Beijing High Innovation Plan under Grant No.20251077Research Fund of National Mobile Communications Research Laboratory,Southeast University under Grant No.2023A03。
文摘The radio frequency(RF)fingerprint technique is a robust method for security enhancement of the physical layer by leveraging the unique RF imperfections inherent in various wireless devices.Among these imperfections,the carrier frequency offset(CFO)stands out as a primary RF fingerprint(RFF)of the transmitter,offering the potential to distinguish among different transmitters.However,accurately estimating CFO in time-varying channels poses significant challenges due to multipath effects and Doppler shifts.In this paper,we focus on estimating CFO for wireless device identification in the orthogonal frequency division multiplexing(OFDM)communication system.To achieve precise CFO estimation under time-varying channels,we propose a frequency domain correlation and spline interpolation(FCSI)algorithm.This approach utilizes pilots distributed across different subcarriers to correlate with prior local sequences,facilitating accurate CFO estimation.Classification is then performed based on the Euclidean distance between the prior RFF and the tested RFF dataset.Simulation results demonstrate that the proposed Mconsecutive average method effectively reduces the classification error rate in the challenging high-frequency(HF)skywave channel environment.
基金supported by the Natural Science Foundation of China (NSFC,No.52372212)。
文摘Photocatalysis uses solar energy to convert nitrogen and water directly into ammonia,helping reduce dependence on fossil fuels and offering a way to integrate the nitrogen cycle into a clean energy network.Ohmic junctions between metals and semiconductors have demonstrated significant advantages in enhancing stability and reducing carrier recombination,but their application in photocatalytic nitrogen fixation is limited due to the difficulty of work function matching and the complexity of fabrication processes.In this study,density functional theory(DFT) calculations were used to confirm the work function matching between Bi and Bi_(2)Ti_(2)O_(7)(BTO),ensuring the formation of an Ohmic junction.A Bi-Bi_(2)Ti_(2)O_(7)(B-BTO) composite was successfully synthesized via a one-step hydrothermal method,using bismuth nitrate and titanium sulfate as precursors.Compared to pure BTO,the B-BTO heterojunction,driven by dual electron injection from both metal Bi and BTO,significantly increased the ammonia synthesis rate to 686.95 μmol g^(-1)h^(-1),making it the most active nitrogen fixation material among similar pyrochlorebased catalysts to date.The differential charge density calculations,photocurrent(i-t) measurements,and photoluminescence(PL) tests further validate the role of Ohmic contacts in enhancing charge transfer and prolonging carrier lifetimes.This research provides valuable insight into the application of Ohmic junctions in photocatalytic nitrogen fixation and contributes to advancements in this field.
文摘Turbulent flow over gravel beds in open channels is a fundamental yet complex problem in hydraulic engineering,as flow behavior is highly sensitive to channel geometry and bed roughness.In this study,the Volume of Fluid(VOF)method coupled with the standard k-εturbulence model is employed to simulate air-water interactions over gravel beds,with open boundary conditions capturing realistic channel-atmosphere interactions.Numerical simulations are performed to examine how channel design influences the relationship between the friction factor(f)and the Reynolds number(RN).Velocity and VOF contours indicate peak flow near the inlet,with a maximum velocity of 0.64 m/s.The simulations show strong agreement with theoretical predictions,yielding a correlation coefficient of 0.99 for RN,while f and Chezy’s coefficient(C)reach 0.75 and 0.71,respectively.Comparison with experimental measurements shows deviations of approximately 17% for RN,25% for f,and 12% for C.Moreover,further analysis confirms an inverse linear relationship between f and RN,in accordance with classical models such as Bazin’s curves,the Colebrook equation,and Moody’s approximation.Overall,the results demonstrate that the proposed numerical framework reliably captures flow dynamics over gravel beds,offering a robust tool for hydraulic design and performance assessment of open channels.
基金supported by the National Natural Science Foundation of China,Nos.81901098(to TC),82201668(to HL)Fujian Provincial Health Technology Project,No.2021QNA072(to HL)。
文摘The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.
基金National Key R&D Program of China,Grant/Award Number:2023YFB2503900National Natural Science Foundation of China,Grant/Award Number:12172143Shenzhen Science and Technology Program,Grant/Award Numbers:JCYJ20220818100418040,JCYJ20220530160816038。
文摘Constructing silicon(Si)-based composite electrodes that possess high energy density,long cycle life,and fast charging capability simultaneously is critical for the development of high performance lithium-ion batteries for mitigating range anxiety and slow charging issues in new energy vehicles.Herein,a thick silicon/carbon composite electrode with vertically aligned channels in the thickness direction(VC-SC)is constructed by employing a bubble formation method.Both experimental characterizations and theoretical simulations confirm that the obtained vertical channel structure can effectively address the problem of sluggish ion transport caused by high tortuosity in conventional thick electrodes,conspicuously enhance reaction kinetics,reduce polarization and side reactions,mitigate stress,increase the utilization of active materials,and promote cycling stability of the thick electrode.Consequently,when paired with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622),the VC-SC||NCM622 pouch type full cell(~6.0 mAh cm^(-2))exhibits significantly improved rate performance and capacity retention compared with the SC||NCM622 full cell with the conventional silicon/carbon composite electrode without channels(SC)as the anode.The assembled VC-SC||NCM622 pouch full cell with a high energy density of 490.3 Wh kg^(-1)also reveals a remarkable fast charging capability at a high current density of 2.0 mA cm^(-2),with a capacity retention of 72.0%after 500 cycles.
基金supported by DST-FIST(Government of India)(Grant No.SR/FIST/MS-1/2017/13)and Seed Money Project(Grant No.DoRDC/733).
文摘This study numerically examines the heat and mass transfer characteristics of two ternary nanofluids via converging and diverg-ing channels.Furthermore,the study aims to assess two ternary nanofluids combinations to determine which configuration can provide better heat and mass transfer and lower entropy production,while ensuring cost efficiency.This work bridges the gap be-tween academic research and industrial feasibility by incorporating cost analysis,entropy generation,and thermal efficiency.To compare the velocity,temperature,and concentration profiles,we examine two ternary nanofluids,i.e.,TiO_(2)+SiO_(2)+Al_(2)O_(3)/H_(2)O and TiO_(2)+SiO_(2)+Cu/H_(2)O,while considering the shape of nanoparticles.The velocity slip and Soret/Dufour effects are taken into consideration.Furthermore,regression analysis for Nusselt and Sherwood numbers of the model is carried out.The Runge-Kutta fourth-order method with shooting technique is employed to acquire the numerical solution of the governed system of ordinary differential equations.The flow pattern attributes of ternary nanofluids are meticulously examined and simulated with the fluc-tuation of flow-dominating parameters.Additionally,the influence of these parameters is demonstrated in the flow,temperature,and concentration fields.For variation in Eckert and Dufour numbers,TiO_(2)+SiO_(2)+Al_(2)O_(3)/H_(2)O has a higher temperature than TiO_(2)+SiO_(2)+Cu/H_(2)O.The results obtained indicate that the ternary nanofluid TiO_(2)+SiO_(2)+Al_(2)O_(3)/H_(2)O has a higher heat transfer rate,lesser entropy generation,greater mass transfer rate,and lower cost than that of TiO_(2)+SiO_(2)+Cu/H_(2)O ternary nanofluid.
文摘The study of stretching surfaces has garnered significant attention due to its importance in a wide range of industrial and engineering functions,including the drawing of wires and plastic films,shrink film production,polymer sheet extrusion,the manufacturing of glass fibers,and the manufacturing of polyester heat-shrink tubing.This research incorporates a Darcy-Forchheimer porous medium to account for the effects of porosity.The governing equations are transformed into a boundary value problem and solved semi-analytically using the Taylor wavelet method.The effects of various parameters are depicted through graphical analyses.The results show that for both converging and diverging stretching surfaces,an increase in the porosity parameter causes a decrease in the velocity field.Additionally,higher Reynolds numbers enhance inertial effects,leading to more pronounced velocity fluctuations.Stretching causes a consistent drop in velocity toward the center and an increase close to the walls in both types of channels,indicating that the volume percentage of nanoparticles influences the heat distribution.Notably,stretching induces a marked temperature drop at the channel's center.
基金supported by the National Natural Science Foundation of China(32322041,W2412029,32321001,32471279)USTC Research Funds of the Double First-Class Initiative(YD9100002004,YD9100002020)+2 种基金Fundamental Research Funds for the Central Universities(WK9100000031)Research Funds of Center for Advanced Interdisciplinary Science and Biomedicine of IHM(QYPY20230034)the Natural Science Foundation of Anhui Province(2408085JX005).
文摘Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.
文摘Taihu Snow (838262) is a home textile manufacturing company listed on the Beijing Stock Exchange in 2022.It is a bedding manufacturer focusing on silk products.The company was esta blished on May 18,2006,Centered around the"Taihu Snow"brand,its products cover suite products (such as pillowcases,quilt covers,sheets),quilt cores,silk scarves and otheremerging retail products.
基金Supported by Calygene Biotechnology Inc.,No.XT[2016]008@。
文摘Type 2 diabetes mellitus(T2DM)is a prevalent metabolic disorder.Despite the availability of numerous pharmacotherapies,a range of adverse reactions,including hypoglycemia,gastrointestinal discomfort,and lactic acidosis,limits their patient applicability and long-term application.Therefore,it is necessary to screen novel therapeutic drugs for T2DM treatment that have high efficacy but few adverse effects.AMP-activated protein kinase(AMPK)stands out as one of the most powerful targets for T2DM treatment.It can be activated through energysensing or calcium signaling.Medications that activate AMPK through the energy-sensing mechanism exhibit remarkable potency,but they are accompanied by lactic acidosis,carrying an alarmingly high mortality rate.Interestingly,medications that activate AMPK through calcium signaling,such as gliclazide,seldom induce lactic acidosis.However,the efficacy of gliclazide is much lower than metformin.Therefore,it is necessary to explore targets that activate AMPK via calcium signaling to avoid lactic acidosis while maintaining high potency.Ion channels are the main controller of intracellular calcium flow.Specific agonists and inhibitors targeting ion channels have been reported to activate AMPK.In this review,we will summarize the structure and function of calcium-permeable ion channels and discuss the potential of targeting these calcium channels for T2DM treatment.
文摘Accurate non-line of sight(NLOS)identification technique in ultra-wideband(UWB)location-based services is critical for applications like drone communication and autonomous navigation.However,current methods using binary classification(LOS/NLOS)oversimplify real-world complexities,with limited generalisation and adaptability to varying indoor environments,thereby reducing the accuracy of positioning.This study proposes an extreme gradient boosting(XGBoost)model to identify multi-class NLOS conditions.We optimise the model using grid search and genetic algorithms.Initially,the grid search approach is used to identify the most favourable values for integer hyperparameters.In order to achieve an optimised model configuration,the genetic algorithm is employed to fine-tune the floating-point hyperparameters.The model evaluations utilise a wide-ranging dataset of real-world measurements obtained with a Qorvo DW1000 UWB device,covering various indoor scenarios.Experimental results show that our proposed XGBoost achieved the highest overall accuracy of 99.47%,precision of 99%,recall of 99%,and an F-score of 99%on an open-source dataset.Additionally,based on a local dataset,the model achieved the highest performance,with an accuracy of 96%,precision of 96%,recall of 97%,and an F-score of 97%.In contrast to current machine learning methods in the literature,the suggestion model enhances classification accuracy and effectively addresses the NLOS/LOS identification as a multiclass propagation channel.This approach provides a robust solution with generalisation and adaptability across various dataset types and environments for more reliable and accurate indoor positioning technologies.
基金supported by the National Natural Science Foundation of China(82301052)China Postdoctoral Science Foundation(2023M732151)+3 种基金Shanxi Provincial Science and Technology Department(202303021212131)Health Commission of Shanxi Province(2022XM14)Shanxi Provincial Education Department(2022L165)Shanxi Medical University(XD2232)。
文摘The huge carrier transfer resistance caused by large-sized"nitrogen pot"severely limits the photocatalytic performance of carbon nitride(CN).This study aims to explore the selection principle of metal ion bridges for constructing dual carrier-transfer channels to delivery carriers to respectively active sites using photodegradation of phenol as the model reaction.Density functional theory(DFT)calculation was used to optimize the structure model of nitrogen vacancies(Nv,provide active sites for reduction of O_(2) and oxidation of phenol)and metal ions(Fe^(3+),Co^(2+),Ni^(2+)or Cu^(2+))co-modified CN,and screen metal ion bridges based on the three parameters including bonding state of metal ion and"nitrogen pot",electrostatic potential(ESP)distribution around the active sites,and three-electron bond length.Both calculation results and activity data show that Fe^(3+),Co^(2+)and Ni^(2+)can construct dual carrier-transfer channels to promote the degradation of phenol while Cu^(2+)cannot Ny and Fe^(3+)co-modified CN(Fe/N_(v)-CN)showed the best catalytic performance among various catalysts and was used as the model catalyst for the detailed characterization to verify the calculation results.This work provides not only the novel strategy for constructing dual carrier-transfer channels in CN,but also the crucial basis for computer simulation as a prediction tool of catalyst structure design rationality.
基金supported by Geological Disaster Patterns and Mitigation Strategies Under River-Reservoir Hydrodynamics in the Three Gorges Reservoir Fluctuation Zone(5000002024CC20004)the National Key Research and Development Program of China(2023YFC3007205)+1 种基金the National Natural Science Foundation of China(No.42271013)the West Light Foundation of the Chinese Academy of Sciences.
文摘The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for estimating SMSQ_DFC do not consider the capacity of the channel cross-section to accommodate sediment materials.This accommodation condition serves as a limiting factor in determining whether the expected surplus of sediment materials can ultimately be stored.To address this issue,a mass-conservative index was used to represent the balance of deposit materials at any cross-section,considering the influx from upstream,outflux to downstream,and accommodation capacity.Based on this index,a new model for estimating SMSQ_DFC was developed and subsequently evaluated.The evaluation results show that the model meets the accuracy requirements with average error rates of 14.06%for self-validation and 14.81%for generalization ability validation.To assess its practical applications,the model was applied to the Yeniu Gully in Wenchuan County,Sichuan Province,an area with detailed field survey data.The results show that the model exhibits a commendable performance.Compared to traditional theoretical and semi-theoretical statistical models,our model is easier to use(input parameters can be obtained using Geographic Information Systems(GIS)).The modeling parameters chosen in this study have more theoretical significance than those used in existing purely statistical models,offering more effective technical support for estimating SMSQ_DFC.
基金supported by the National Key R&D Program of China under Grant No.2023YFB2904802National Natural Science Foundation of China under Grant Nos.62301022,62221001,62431003,and 62101507+1 种基金Young Elite Scientists Sponsorship Program by CAST under Grant No.2022QNRC001Program for Science&Technology R&D Plan Joint Fund of Henan Province under Grant No.225200810112。
文摘Reliable channel data helps characterize the limitations and performance boundaries of communication technologies accurately.However,channel measurement is highly costly and time-consuming,and taking actual measurement as the only channel data source may reduce efficiency because of the constraints of high testing difficulty and limited data volume.Although existing standard channel models can generate channel data,their authenticity and diversity cannot be guaranteed.To address this,we use deep learning methods to learn the attributes of limited measured data and propose a generative model based on generative adversarial networks to rapidly synthesize data.A software simulation platform is also established to verify that the proposed model can generate data that are statistically similar to the measured data while maintaining necessary randomness.The proposed algorithm and platform can be applied to channel data enhancement and serve channel modeling and algorithm evaluation applications with urgent needs for data.
基金supported in part by the Natural Science Foundation of Xinjiang Uygur Autonomous Region under Grant 2022D01B184the National Natural Science Foundation of China under Grant 62301117,62131005.
文摘Covert communication guarantees the security of wireless communications via hiding the existence of the transmission.This paper focuses on the first and second order asymptotics of covert communication in the AWGN channels.The covertness is measured by the total variation distance between the channel output distributions induced with and without the transmission.We provide the exact expressions of the maximum amount of information that can be transmitted with the maximum error probability and the total variation less than any small numbers.The energy detection and the random coding are employed to prove our results.We further compare our results with those under relative entropy.The results show how many additional amounts of information can be transmitted covertly when changing the covertness constraint to total variation.
基金supported by the National Natural Science Foundation of China(22272150)the Major Program of Zhejiang Provincial Natural Science Foundation of China(LD22B030002)+2 种基金the Zhejiang Provincial Ten Thousand Talent Program(2021R51009)the Zhejiang Provincial Natural Science of China(LZ23B030001)the Key Science and Technology Project of Jinhua City(2022-1-083,2023-1-093).
文摘Aqueous zinc-ion batteries(ZIBs)are promising candidates for next-generation energy storage,but the problems related to Zn dendrites and side reactions severely hinder their practical applications.Herein,a self-recognition separator based on a Bi-based metal-organic framework(GF@CAU-17)is developed for ion management to achieve highly reversible Zn anodes.The GF@CAU-17 has self-recognition behavior to customize selective Zn^(2+)channels,effectively repelling SO_(4)^(2-)and H_(2)O,but facilitating Zn^(2+)conduction.The inherent properties of CAU-17 result in the repulsion of SO_(4)^(2-)ions while disrupting the hydrogen bond network among free H_(2)O molecules,restraining side reactions and by-products.Simultaneously,the zincophilic characteristic of CAU-17 expedites the desolvation of[Zn(H_(2)O)6]^(2+),leading to a self-expedited Zn^(2+)ion pumping effect that dynamically produces a steady and homogeneous Zn^(2+)ion flux,and thereby alleviates concentration polarization.Consequently,a symmetric cell based on the GF@CAU-17 separator can achieve a long lifespan of 4450 h.Moreover,the constructed Zn//GF@CAU-17//MnO_(2)cell delivers a high specific capacity of 221.8 mAh g^(-1)and 88.0%capacity retention after 2000 cycles.
基金supported by the National Natural Science Foundation of China(Grant Nos.62371240,61802175,62401266,and 12201300)the National Key R&D Program of China(Grant No.2022YFB3103800)+2 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20241452)the Fundamental Research Funds for the Central Universities(Grant No.30923011014)the fund of Laboratory for Advanced Computing and Intelligence Engineering(Grant No.2023-LYJJ-01-009)。
文摘To improve the decoding performance of quantum error-correcting codes in asymmetric noise channels,a neural network-based decoding algorithm for bias-tailored quantum codes is proposed.The algorithm consists of a biased noise model,a neural belief propagation decoder,a convolutional optimization layer,and a multi-objective loss function.The biased noise model simulates asymmetric error generation,providing a training dataset for decoding.The neural network,leveraging dynamic weight learning and a multi-objective loss function,mitigates error degeneracy.Additionally,the convolutional optimization layer enhances early-stage convergence efficiency.Numerical results show that for bias-tailored quantum codes,our decoder performs much better than the belief propagation(BP)with ordered statistics decoding(BP+OSD).Our decoder achieves an order of magnitude improvement in the error suppression compared to higher-order BP+OSD.Furthermore,the decoding threshold of our decoder for surface codes reaches a high threshold of 20%.
基金supported by the European Union’s Horizon 2022 Research and Innovation Programme under Marie Skłodowska-Curie Grant No.10110799.
文摘In this paper,we investigate the performance of physical layer security(PLS)over reconfigurable intelligent surfaces(RIS)-aided wireless communication systems,where all fading channels are modeled with Fisher-Snedecor F distribution.Specifically,we consider a RIS with N reflecting elements between the transmitter and the legitimate receiver to develop a smart environment and also meliorate secure communications.In this regard,we derive the closed-form expressions for the secrecy outage probability(SOP)and average secrecy capacity(ASC).We also analyze the asymptotic behaviour of the SOP and ASC by exploiting the residue approach.Monte-Carlo(MC)simulation results are provided throughout to validate the correctness of the developed analytical results,showing that considering RIS in wireless communication systems has constructive effects on the secrecy performance.
基金supported by the Fund of the National Key Laboratory of Plasma Physics(Grant No.6142A04230204)the National Natural Science Foundation of China(Project No.12075046).
文摘We propose a photon-photon collider based on synchrotron gamma sources driven by relativistic electron beams in hollow plasma channels.The collimated(with a divergence angle of~1 mrad)and ultrabrilliant(>10^(28)photons s^(-1)·mrad^(-2)·mm^(-2)per 0.1% bandwidth at 0.6 MeV)photon beams are generated by strong electromagnetic fields induced by current filamentation instability,and up to~10^(6) Breit-Wheeler(BW)pairs can be created per shot.Notably,the usage of hollow plasma channels not only enhances synchrotron radiation,but also allows flexible control of the produced photon beams,ensuring the alignment of the two colliding beams and maximizing the two-photon BW process.This setup has the advantage of a clean background by eliminating the yield from the nonlinear BW process,and the signal-to-noise ratio is higher than 10^(2).
