A learning algorithm based on a hard limiter for feedforward neural networks (NN) is presented,and is applied in solving classification problems on separable convex sets and disjoint sets.It has been proved that the a...A learning algorithm based on a hard limiter for feedforward neural networks (NN) is presented,and is applied in solving classification problems on separable convex sets and disjoint sets.It has been proved that the algorithm has stronger classification ability than that of the back propagation (BP) algorithm for the feedforward NN using sigmoid function by simulation.What is more,the models can be implemented with lower cost hardware than that of the BP NN.LEARNIN展开更多
At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systema...At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater.展开更多
Liver transplantation(LT)remains the optimal life-saving intervention for patients with end-stage liver disease.Despite the recent advances in LT several barriers,including organ allocation,donor-recipient matching,an...Liver transplantation(LT)remains the optimal life-saving intervention for patients with end-stage liver disease.Despite the recent advances in LT several barriers,including organ allocation,donor-recipient matching,and patient education,persist.With the growing progress of artificial intelligence,particularly large language models(LLMs)like ChatGPT,new applications have emerged in the field of LT.Current studies demonstrating usage of ChatGPT in LT include various areas of application,from clinical settings to research and education.ChatGPT usage can benefit both healthcare professionals,by decreasing the time spent on non-clinical work,but also LT recipients by providing accurate information.Future potential applications include the expanding usage of ChatGPT and other LLMs in the field of LT pathology and radiology as well as the automated creation of discharge summaries or other related paperwork.Additionally,the next models of ChatGPT might have the potential to provide more accurate patient education material with increased readability.Although ChatGPT usage presents promising applications,there are certain ethical and practical limitations.Key concerns include patient data privacy,information accuracy,misinformation possibility and lack of legal framework.Healthcare providers and policymakers should collaborate for the establishment of a controlled framework for the safe use of ChatGPT.The aim of this minireview is to summarize current literature on ChatGPT in LT,highlighting both opportunities and limitations,while also providing future possible applications.展开更多
Pelagic appendicularians,known for their rapid bloom capability,are important secondary producers and play essential roles in marine ecosystems.To assess the environmental adaptation of the most common appendicularian...Pelagic appendicularians,known for their rapid bloom capability,are important secondary producers and play essential roles in marine ecosystems.To assess the environmental adaptation of the most common appendicularian species Oikopleura dioica in Jiaozhou Bay,Shandong,China,its annual variations in abundance and body size were investigated monthly at 12 stations in 2011,and the relationship between somatic growth and gonadal development was compared with previously published laboratory data.Oikopleura dioica exhibited distinct seasonal abundance patterns,peaking in summer and autumn,particularly in the inner bay,reflecting its adaptation to the eutrophic conditions and high food availability.Compared to laboratory results,O.dioica in Jiaozhou Bay exhibited shorter body lengths,smaller gonad volumes,and earlier maturation at reduced body sizes,despite high natural chlorophyll-a concentration,suggesting that factors beyond food availability,such as resource competition and environmental stressors,may limit its growth in natural settings.Correlation analysis indicated that the somatic growth of natural O.dioica was primarily influenced by temperature,while gonadal development was related to chlorophyll-a concentration,and its population abundance was linked to food availability and the abundance of other zooplankton,such as copepods and jellyfish.It was suggested that the growth and recruitment of O.dioica were constrained by resource limitations in natural environments,further exacerbated by interactions with other zooplankton,including predation and competition.This study provides valuable data on the mechanisms underlying bio-environmental interactions and their spatiotemporal variations,offering critical insights into the ecological roles of appendicularians in marine ecosystems.展开更多
In order to enable wing morphing(e.g.change in camber or folds)without incurring additional weight to the aircraft,lightweight flexible materials such as membrane are needed.However,the research on fluid-structure cou...In order to enable wing morphing(e.g.change in camber or folds)without incurring additional weight to the aircraft,lightweight flexible materials such as membrane are needed.However,the research on fluid-structure coupling of membranes has mainly focused on parachutes in low-speed conditions,while that in supersonic flow conditions is lacking.Here,the degraded shell method is proposed to study membrane deformation by using shell element,which is more effective than using membrane elements directly.A fluid-structure interaction computational framework is proposed,whereby the aerodynamic module is composed of either the piston theory or computational fluid dynamics.A rectangular membrane of length 0.4 m and width 0.6 m is investigated in supersonic conditions.The characteristics of the limit cycle and steady deformation are analyzed,considering the effects of angle of attack and dynamic pressure.It is found that the structural response exhibits significant differences under various angles of attack.Furthermore,initial relaxation of membrane has significant influence on the structural deformation.Finally,the aeroelastic scaling method for membrane structures is derived,providing guidance for the design of wind tunnel models.This study provides a theoretical foundation for the analysis and application of membrane structures under supersonic conditions in future research.展开更多
In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorit...In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorithm under communication constraints to achieve accurate system states of the interested system.An output-based event-triggered scheme is first employed to alleviate transmission burden.Accounting for the limited-communication-induced measurement bias,a novel bias calibration algorithm following the Kalman filtering line is developed to restrain the effect of the measurement bias on system estimation,thereby achieving accurate system state estimates.Subsequently,the Field Programmable Gate Array(FPGA)implementation of the proposed algorithm is also realized with the hope of providing fast bias calibration in practical scenarios.A simulation about a numerical example and a practical example(for gyroscope’s angular velocity bias calibration)on MATLAB is provided to demonstrate the feasibility and effectiveness of the proposed algorithm.展开更多
In this paper,we derive the sub-Riemannian version of the Kastler-Kalau-Walze type theorem and the Dabrowski-Sitarz-Zalecki type theorem for the twisted BCV spaces.We also compute the Connes conformal invariants for t...In this paper,we derive the sub-Riemannian version of the Kastler-Kalau-Walze type theorem and the Dabrowski-Sitarz-Zalecki type theorem for the twisted BCV spaces.We also compute the Connes conformal invariants for the twisted product,as well as the sub-Riemannian limits of the Connes conformal invariants for the twisted BCV spaces.展开更多
Plants encounter dynamic light environments in natural field conditions,and species differ in their physiological and biochemical mechanisms for acclimating to fluctuating light(FL).The manner in which soybean(Glycine...Plants encounter dynamic light environments in natural field conditions,and species differ in their physiological and biochemical mechanisms for acclimating to fluctuating light(FL).The manner in which soybean(Glycine max(L.) Merr.) coordinates multiple physiological adjustments to FL remains poorly understood.This study assessed the effects of FL on soybean morphology and photosynthetic traits by examining changes in photosynthetic gas exchange parameters and chlorophyll(Chl) a fluorescence under alternating high-and low-light conditions.Results indicated that soybeans exposed to FL exhibited reduced dry matter accumulation,smaller and thinner leaves,and a lower Chl a/Chl b levels-characteristics typically associated with plants grown under continuous low-light.Despite these morphological similarities,their photosynthetic gas exchange rates and photosynthetic capacity were maintained at levels comparable to those under steady high light,unlike plants grown under constant low-light.Thus,acclimation to FL is distinct from adaptation to sustained low-light conditions.Correlation analyses revealed that the decline in carbon assimilation under FL primarily stemmed from two factors:the slow recovery of stomatal conductance upon transition to high light and the delayed relaxation of nonphotochemical quenching when light intensity decreased.Therefore,the reduction in carbon assimilation under FL cannot be attributed to low-light phase adjustments but rather reflects a lag in photosynthetic responsiveness to changing light conditions.展开更多
Urban tunnels are often built in multiples,yet the influence of surface structures on their support demands is frequently overlooked,highlighting the need for refined design under realistic loading.This study addresse...Urban tunnels are often built in multiples,yet the influence of surface structures on their support demands is frequently overlooked,highlighting the need for refined design under realistic loading.This study addresses this gap by examining the response of a uniformly loaded strip footing above twin horseshoe tunnels with structural linings.A non-dimensional Footing Stability Improvement Factor(I_(f)),defined as the ratio of ultimate bearing capacity with and without lining to that of a footing on intact rock—is evaluated using adaptive finite element limit analysis.The effects of normalized vertical depth of tunnel,normalised horizontal spacing of tunnel,and lining-thickness factor are examined,providing key insights into foundation-tunnel interaction and support optimization.This study finds that,for unlined twin tunnels,footing-tunnel interaction becomes negligible when embedment exceeds four times of footing widths and tunnel spacing surpasses eleven times of footing widths,beyond which additional support is unnecessary.For lined tunnels,the tunnel-lining thickness required to maintain footing stability equivalent to that on intact rock decreases rapidly with embedment depth.At a tunnel spacing equal to onehalf of the footing width,the critical lining-thickness ratio is about six percent of the footing width at a tunnel depth of half the footing width,reducing to approximately five,four,and three percent at depths of one,one-and-a-half,and two footing widths,and asymptotically approaching nearly one percent for embedment depths exceeding two-and-a-half footing widths.Additionally,rock mass parameters exhibit minimal impact(±2%)on I_(f).The results show that failure mechanisms in footing-tunnel systems are primarily governed by tunnels-positional parmeters,and lining thickness.The study presents a mechanistic framework that delineates the critical depth-spacing-thickness regimes controlling twin-tunnel behavior,providing engineers with clear design boundaries and performance-based lining guidelines to improve the stability of both tunnels and overlying foundations.展开更多
To address the issues of high costs and low component utilization caused by the independent configuration of hybrid DC circuit breakers(HCBs)and DC power flow controllers(DCPFCs)at each port in existing DC distributio...To address the issues of high costs and low component utilization caused by the independent configuration of hybrid DC circuit breakers(HCBs)and DC power flow controllers(DCPFCs)at each port in existing DC distribution networks,this paper adopts a component sharing mechanism to propose a composite multi-port hybrid DC circuit breaker(CM-HCB)with DC power flow and fault current limitation abilities,as well as reduced component costs.The proposed CM-HCB topology enables the sharing of the main breaker branch(MB)and the energy dissipation branch,while the load commutation switches(LCSs)in the main branch are reused as power flow control components,enabling flexible regulation of power flow in multiple lines.Meanwhile,by reconstructing the current path during the fault process,the proposed CM-HCB can utilize the internal coupled inductor to limit the current rise rate at the initial stage of the fault,significantly reducing the requirement for breaking current.A detailed study on the topological structure,steady-state power flow regulation mechanism,transient fault isolation mechanism,control strategy and characteristic analysis of the proposed CM-HCB is presented.Then,a Matlab/Simulink-based meshed three-terminal DC grid simulation platform with the proposed CM-HCB is built.The results indicate that the proposed CM-HCB can not only achieve flexible power flow control during steady-state operation,but also obtain current rise limitation and fault isolation abilities under short-circuit fault conditions,verifying its correctness and effectiveness.Finally,a comparative economic analysis is conducted between the proposed CM-HCB and the other two existing solutions,confirming that its component sharing mechanism can significantly reduce the number of components,lower system costs,and improve component utilization.展开更多
A scheme is proposed based on a Mach-Zehnder interferometer with high phase sensitivity,utilizing a two-mode squeezed coherent state,generated by four-wave mixing,as input.The phase sensitivity of this scheme easily s...A scheme is proposed based on a Mach-Zehnder interferometer with high phase sensitivity,utilizing a two-mode squeezed coherent state,generated by four-wave mixing,as input.The phase sensitivity of this scheme easily surpasses the Heisenberg limit when intensity difference detection is applied.Under phase-matching conditions,the quantum Cramér-Rao bound significantly exceeds the Heisenberg limit.Additionally,the scheme exhibits robustness against photon loss.When compared with the modified SU(1,1)interferometer with two coherent state inputs,this approach demonstrates superior measurement sensitivity,evaluated through various detection methods and the quantum Cramér-Rao bound.This work holds potential applications in quantum metrology.展开更多
The quality of cardiopulmonary resuscitation(CPR) significantly influences survival and neurological outcomes in patients with cardiac arrest(CA).Although mechanical chest compression devices and extracorporeal cardio...The quality of cardiopulmonary resuscitation(CPR) significantly influences survival and neurological outcomes in patients with cardiac arrest(CA).Although mechanical chest compression devices and extracorporeal cardiopulmonary resuscitation(ECPR) have demonstrated some benefits,high-quality manual CPR remained the essential first step,particularly in resource-limited settings.In this study,we examined whether opportunities existed to improve manual CPR performance using preliminary data from our recent survey conducted in a province in western China.We aim to emphasize the importance of improving manual CPR quality before implementing advanced interventions.展开更多
The porous NiO nanoplates modified with rGO nanosheets and SnO_(2)nanoparticles are developed for accurate and rapid ppb-level NO_(2)detection.The developed SnO_(2)/NiO/rGO sensor towards 50 ppm NO_(2)gas demonstrates...The porous NiO nanoplates modified with rGO nanosheets and SnO_(2)nanoparticles are developed for accurate and rapid ppb-level NO_(2)detection.The developed SnO_(2)/NiO/rGO sensor towards 50 ppm NO_(2)gas demonstrates an excellent gas-sensing response of 14.8 at 23℃,which is 3.03 times that of Ni O/rGO sensor(4.89)and 6.49 times that of NiO sensor(2.28),respectively.The developed SnO_(2)/NiO/rGO sensor exhibits faster response/recovery speed(12.7/32.8 s@5 ppm),with extra-low theoretical detection limit of 0.15 ppb at room temperature.More fascinatingly,our sensors indicate great sensitivity,outstanding repeatability and long-term stability for longer than 7 weeks.Additionally,it also suggests that 1℃and 1%relative humidity have the same effect on the SnO_(2)/NiO/rGO sensor signal as approximately 13 ppb and 7.0 ppb NO_(2)gas change,respectively.Such excellent properties are mainly attributed to the large surface-to-volume ratio,which provides active sites to NO_(2)gas spread,adsorption and diffusion on material surface in redox reaction.Moreover,the ternary heterojunctions formed by NiO,rGO and SnO_(2)may serve as highly conductive channels to accelerate carrier transfer and abundant oxygen vacancies to reduce the adsorption energy for O_(2)and NO_(2)gas,thus further improving performance of the sensors.展开更多
Low-cost and high-safety aqueous Zn-I_(2) batteries attract extensive attention for large-scale energy storage systems.However,polyiodide shuttling and sluggish iodine conversion reactions lead to inferior rate capabi...Low-cost and high-safety aqueous Zn-I_(2) batteries attract extensive attention for large-scale energy storage systems.However,polyiodide shuttling and sluggish iodine conversion reactions lead to inferior rate capability and severe capacity decay.Herein,a three-dimensional polyaniline is wrapped by carboxylcarbon nanotubes(denoted as C-PANI)which is designed as a catalytic cathode to effectively boost iodine conversion with suppressed polyiodide shuttling,thereby improving Zn-I_(2) batteries.Specifically,carboxyl-carbon nanotubes serve as a proton reservoir for more protonated-NH+=sites in PANI chains,achieving a direct I0/I−reaction for suppressed polyiodide generation and Zn corrosion.Attributing to this“proton-iodine”regulation,catalytic protonated C-PANI strongly fixes electrolytic iodine species and stores proton ions simultaneously through reversible-N=/-NH^(+)-reaction.Therefore,the electrolytic Zn-I_(2) battery with C-PANI cathode exhibits an impressive capacity of 420 mAh g^(−1) and ultra-long lifespan over 40,000 cycles.Additionally,a 60 mAh pouch cell was assembled with excellent cycling stability after 100 cycles,providing new insights into exploring effective organocatalysts for superb Zn-halogen batteries.展开更多
The GaInSn liquid metal current limiter based on the fluid pinch effect has broad application prospects due to its particular properties. However, the limited rated current and abil- ity of power dissipation are the c...The GaInSn liquid metal current limiter based on the fluid pinch effect has broad application prospects due to its particular properties. However, the limited rated current and abil- ity of power dissipation are the critical problems for its wide application. Firstly, the temperature distribution of the liquid metal current limiter （LMCL） was obtained by experiments with a rated current of 1 kA and the arc ignition phenomenon was observed with 1.5 kA, which indicates that the rated current is mainly limited by the arc rather than the high temperature compared to the traditional switchgears. Furthermore, an improved method is proposed by adding the paralleled pure resistance, impedance or another LMCL element to protect the setup from the fault energy concentration in the setup. The problem of a slower arc voltage increasing rate can be solved by adding a paralleled impedance with suitable parameters. Finally, the current limiting properties based on the improved method were investigated and the alternating oscillating current was found between two paralleled LMCL elements owing to their deviation of arc ignition in reality.展开更多
A novel class of weighted essentially nonoscillatory （WENO） schemes based on Hermite polynomi- als, termed as HWENO schemes, is developed and applied as limiters for high order discontinuous Galerkin （DG） method o...A novel class of weighted essentially nonoscillatory （WENO） schemes based on Hermite polynomi- als, termed as HWENO schemes, is developed and applied as limiters for high order discontinuous Galerkin （DG） method on triangular grids. The developed HWENO methodology utilizes high-order derivative information to keep WENO re- construction stencils in the von Neumann neighborhood. A simple and efficient technique is also proposed to enhance the smoothness of the existing stencils, making higher-order scheme stable and simplifying the reconstruction process at the same time. The resulting HWENO-based limiters are as compact as the underlying DG schemes and therefore easy to implement. Numerical results for a wide range of flow conditions demonstrate that for DG schemes of up to fourth order of accuracy, the designed HWENO limiters can simul- taneously obtain uniform high order accuracy and sharp, es- sentially non-oscillatory shock transition.展开更多
A two-dimensional （2D） dam-break flow numerical model was developed based on the finite-volume total variation diminishing （TVD） and monotone upstream-centered scheme for conservation laws （MUSCL）-Hancock scheme...A two-dimensional （2D） dam-break flow numerical model was developed based on the finite-volume total variation diminishing （TVD） and monotone upstream-centered scheme for conservation laws （MUSCL）-Hancock scheme, which has second-order accuracy in both time and space. A Harten-Lax-van Leer-contact （HLLC） approximate Riemann solver was used to evaluate fluxes. The TVD MUSCL-Hancock numerical scheme utilizes slope limiters, such as the minmod, double minmod, superbee, van Albada, and van Leer limiters, to prevent spurious oscillations and maintain monotonicity near discontinuities. A comparative study of the impact of various slope limiters on the accuracy of the numerical flow model was conducted with several dam-break examples including wet and dry bed cases. The numerical results of the superbee and double minmod limiters agree better with the theoretical solution and have higher accuracy than other limiters in one-dimensional （1D） space. The ratio of the downstream water depth to the upstream water depth was used to select the proper slope limiter. For the 2D numerical model, the superbee limiter should not be used, owing to significant numerical dispersion.展开更多
A novel plasma limiter, in which the plasma is excited by surface wave, is presented. The breakdown time of some gases filled in the limiter were calculated as a function of gas pres- sure, ionization degree and densi...A novel plasma limiter, in which the plasma is excited by surface wave, is presented. The breakdown time of some gases filled in the limiter were calculated as a function of gas pres- sure, ionization degree and density of seed electrons under low pressure （0.01 -1 Torr） and high pressure （10 -1000 Torr） cases. The results show that the limiter filled with Xe with a pressure of 0.9 Torr, seed electron density of 10^16 m^-3, and ionization degree of 10^-4, has a breakdown time of approximate 19.6 ns.展开更多
A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST tokamak.The results revealed that after a plasma operation o...A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST tokamak.The results revealed that after a plasma operation of a few seconds,the layer became clear,which indicated a strong Li emission with a decrease in the limiter surface temperature.This emission resulted in a dense vapour around the limiter,and Li ions moved along the magnetic fleld to form a green shielding layer on the limiter.The plasma heat flux loaded on the limiter,measured by the probe installed on the limiter,was approximately 52%lower than that detected by a fast-reciprocating probe at the same radial position without the limiter in EAST.Additionally,approximately 42%of the parallel heat flux was dissipated directly with the enhanced Li radiation in the discharge with the liquid metal infused trenches(LIMIT)limiter.This observation revealed that the Li vapour layer exhibited an excellent shielding effect to liquid Li on plasma heat flux,which is a possible beneflt of liquid-plasma-facing components in future fusion devices.展开更多
The liquid metal current limiter(LMCL)is regarded as a viable solution for reducing the fault current in a power grid.But demonstrating the liquid metal arc plasma self-pinching process of the resistive wall,and reduc...The liquid metal current limiter(LMCL)is regarded as a viable solution for reducing the fault current in a power grid.But demonstrating the liquid metal arc plasma self-pinching process of the resistive wall,and reducing the erosion of the LMCL are challenging,not only theoretically,but also practically.In this work,a novel LMCL is designed with a resistive wall that can be connected to the current-limiting circuit inside the cavity.Specifically,a novel fault current limiter(FCL)topology is put forward where the novel LMCL is combined with a fast switch and current-limiting reactor.Further,the liquid metal self-pinch effect is modeled mathematically in three dimensions,and the gas-liquid two-phase dynamic diagrams under different short-circuit currents are obtained by simulation.The simulation results indicate that with the increase of current,the time for the liquid metal-free surface to begin depressing is reduced,and the position of the depression also changes.Different kinds of bubbles formed by the depressions gradually extend,squeeze,and break.With the increase of current,the liquid metal takes less time to break,but breaks still occur at the edge of the channel,forming arc plasma.Finally,relevant experiments are conducted for the novel FCL topology.The arcing process and current transfer process are analyzed in particular.Comparisons of the peak arc voltage,arcing time,current limiting efficiency,and electrode erosion are presented.The results demonstrate that the arc voltage of the novel FCL topology is reduced by more than 4.5times and the arcing time is reduced by more than 12%.The erosions of the liquid metal and electrodes are reduced.Moreover,the current limiting efficiency of the novel FCL topology is improved by 1%–5%.This work lays a foundation for the topology and optimal design of the LMCL.展开更多
文摘A learning algorithm based on a hard limiter for feedforward neural networks (NN) is presented,and is applied in solving classification problems on separable convex sets and disjoint sets.It has been proved that the algorithm has stronger classification ability than that of the back propagation (BP) algorithm for the feedforward NN using sigmoid function by simulation.What is more,the models can be implemented with lower cost hardware than that of the BP NN.LEARNIN
基金supported by the National Natural Science Foundation of China(Project No.42307555).
文摘At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater.
文摘Liver transplantation(LT)remains the optimal life-saving intervention for patients with end-stage liver disease.Despite the recent advances in LT several barriers,including organ allocation,donor-recipient matching,and patient education,persist.With the growing progress of artificial intelligence,particularly large language models(LLMs)like ChatGPT,new applications have emerged in the field of LT.Current studies demonstrating usage of ChatGPT in LT include various areas of application,from clinical settings to research and education.ChatGPT usage can benefit both healthcare professionals,by decreasing the time spent on non-clinical work,but also LT recipients by providing accurate information.Future potential applications include the expanding usage of ChatGPT and other LLMs in the field of LT pathology and radiology as well as the automated creation of discharge summaries or other related paperwork.Additionally,the next models of ChatGPT might have the potential to provide more accurate patient education material with increased readability.Although ChatGPT usage presents promising applications,there are certain ethical and practical limitations.Key concerns include patient data privacy,information accuracy,misinformation possibility and lack of legal framework.Healthcare providers and policymakers should collaborate for the establishment of a controlled framework for the safe use of ChatGPT.The aim of this minireview is to summarize current literature on ChatGPT in LT,highlighting both opportunities and limitations,while also providing future possible applications.
基金Supported by the National Key Research and Development Program of China(Nos.2023YFC3108205,2023YFC3108201)the National Natural Science Foundation of China(No.42306153)。
文摘Pelagic appendicularians,known for their rapid bloom capability,are important secondary producers and play essential roles in marine ecosystems.To assess the environmental adaptation of the most common appendicularian species Oikopleura dioica in Jiaozhou Bay,Shandong,China,its annual variations in abundance and body size were investigated monthly at 12 stations in 2011,and the relationship between somatic growth and gonadal development was compared with previously published laboratory data.Oikopleura dioica exhibited distinct seasonal abundance patterns,peaking in summer and autumn,particularly in the inner bay,reflecting its adaptation to the eutrophic conditions and high food availability.Compared to laboratory results,O.dioica in Jiaozhou Bay exhibited shorter body lengths,smaller gonad volumes,and earlier maturation at reduced body sizes,despite high natural chlorophyll-a concentration,suggesting that factors beyond food availability,such as resource competition and environmental stressors,may limit its growth in natural settings.Correlation analysis indicated that the somatic growth of natural O.dioica was primarily influenced by temperature,while gonadal development was related to chlorophyll-a concentration,and its population abundance was linked to food availability and the abundance of other zooplankton,such as copepods and jellyfish.It was suggested that the growth and recruitment of O.dioica were constrained by resource limitations in natural environments,further exacerbated by interactions with other zooplankton,including predation and competition.This study provides valuable data on the mechanisms underlying bio-environmental interactions and their spatiotemporal variations,offering critical insights into the ecological roles of appendicularians in marine ecosystems.
文摘In order to enable wing morphing(e.g.change in camber or folds)without incurring additional weight to the aircraft,lightweight flexible materials such as membrane are needed.However,the research on fluid-structure coupling of membranes has mainly focused on parachutes in low-speed conditions,while that in supersonic flow conditions is lacking.Here,the degraded shell method is proposed to study membrane deformation by using shell element,which is more effective than using membrane elements directly.A fluid-structure interaction computational framework is proposed,whereby the aerodynamic module is composed of either the piston theory or computational fluid dynamics.A rectangular membrane of length 0.4 m and width 0.6 m is investigated in supersonic conditions.The characteristics of the limit cycle and steady deformation are analyzed,considering the effects of angle of attack and dynamic pressure.It is found that the structural response exhibits significant differences under various angles of attack.Furthermore,initial relaxation of membrane has significant influence on the structural deformation.Finally,the aeroelastic scaling method for membrane structures is derived,providing guidance for the design of wind tunnel models.This study provides a theoretical foundation for the analysis and application of membrane structures under supersonic conditions in future research.
基金support from the National Natural Science Foundation of China(Grant Nos.U2330206,U2230206,62173068)Sichuan Science and Technology Program(Grants Nos.2024NSFSC1483,2024ZYD0156,2023NSFC1962,DQ202412).
文摘In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorithm under communication constraints to achieve accurate system states of the interested system.An output-based event-triggered scheme is first employed to alleviate transmission burden.Accounting for the limited-communication-induced measurement bias,a novel bias calibration algorithm following the Kalman filtering line is developed to restrain the effect of the measurement bias on system estimation,thereby achieving accurate system state estimates.Subsequently,the Field Programmable Gate Array(FPGA)implementation of the proposed algorithm is also realized with the hope of providing fast bias calibration in practical scenarios.A simulation about a numerical example and a practical example(for gyroscope’s angular velocity bias calibration)on MATLAB is provided to demonstrate the feasibility and effectiveness of the proposed algorithm.
基金Supported by Science and Technology Development Plan Project of Jilin Province China(Grant No.20260102245JC)Supported by National Natural Science Foundation of China(Grant No.11771070).
文摘In this paper,we derive the sub-Riemannian version of the Kastler-Kalau-Walze type theorem and the Dabrowski-Sitarz-Zalecki type theorem for the twisted BCV spaces.We also compute the Connes conformal invariants for the twisted product,as well as the sub-Riemannian limits of the Connes conformal invariants for the twisted BCV spaces.
基金supported by the National Key Research and Development Program of China (2023YFF1001504)the National Natural Science Foundation of China (32071963)+2 种基金the National Key Research and Development Program of China (2022YFD2300902)the Guangxi Key Research and Development Program of China (GuikeAB23026107)the Chengdu Science and Technology Project,China (2023-YF08-00003-SN)。
文摘Plants encounter dynamic light environments in natural field conditions,and species differ in their physiological and biochemical mechanisms for acclimating to fluctuating light(FL).The manner in which soybean(Glycine max(L.) Merr.) coordinates multiple physiological adjustments to FL remains poorly understood.This study assessed the effects of FL on soybean morphology and photosynthetic traits by examining changes in photosynthetic gas exchange parameters and chlorophyll(Chl) a fluorescence under alternating high-and low-light conditions.Results indicated that soybeans exposed to FL exhibited reduced dry matter accumulation,smaller and thinner leaves,and a lower Chl a/Chl b levels-characteristics typically associated with plants grown under continuous low-light.Despite these morphological similarities,their photosynthetic gas exchange rates and photosynthetic capacity were maintained at levels comparable to those under steady high light,unlike plants grown under constant low-light.Thus,acclimation to FL is distinct from adaptation to sustained low-light conditions.Correlation analyses revealed that the decline in carbon assimilation under FL primarily stemmed from two factors:the slow recovery of stomatal conductance upon transition to high light and the delayed relaxation of nonphotochemical quenching when light intensity decreased.Therefore,the reduction in carbon assimilation under FL cannot be attributed to low-light phase adjustments but rather reflects a lag in photosynthetic responsiveness to changing light conditions.
文摘Urban tunnels are often built in multiples,yet the influence of surface structures on their support demands is frequently overlooked,highlighting the need for refined design under realistic loading.This study addresses this gap by examining the response of a uniformly loaded strip footing above twin horseshoe tunnels with structural linings.A non-dimensional Footing Stability Improvement Factor(I_(f)),defined as the ratio of ultimate bearing capacity with and without lining to that of a footing on intact rock—is evaluated using adaptive finite element limit analysis.The effects of normalized vertical depth of tunnel,normalised horizontal spacing of tunnel,and lining-thickness factor are examined,providing key insights into foundation-tunnel interaction and support optimization.This study finds that,for unlined twin tunnels,footing-tunnel interaction becomes negligible when embedment exceeds four times of footing widths and tunnel spacing surpasses eleven times of footing widths,beyond which additional support is unnecessary.For lined tunnels,the tunnel-lining thickness required to maintain footing stability equivalent to that on intact rock decreases rapidly with embedment depth.At a tunnel spacing equal to onehalf of the footing width,the critical lining-thickness ratio is about six percent of the footing width at a tunnel depth of half the footing width,reducing to approximately five,four,and three percent at depths of one,one-and-a-half,and two footing widths,and asymptotically approaching nearly one percent for embedment depths exceeding two-and-a-half footing widths.Additionally,rock mass parameters exhibit minimal impact(±2%)on I_(f).The results show that failure mechanisms in footing-tunnel systems are primarily governed by tunnels-positional parmeters,and lining thickness.The study presents a mechanistic framework that delineates the critical depth-spacing-thickness regimes controlling twin-tunnel behavior,providing engineers with clear design boundaries and performance-based lining guidelines to improve the stability of both tunnels and overlying foundations.
基金funded by Youth Talent Growth Project of Guizhou Provincial Department of Education(No.Qianjiaoji[2024]21)National Natural Science Foundation of China(No.62461008 and No.52507211)Guizhou Provincial Key Technology R&D Program(No.[2024]General 049).
文摘To address the issues of high costs and low component utilization caused by the independent configuration of hybrid DC circuit breakers(HCBs)and DC power flow controllers(DCPFCs)at each port in existing DC distribution networks,this paper adopts a component sharing mechanism to propose a composite multi-port hybrid DC circuit breaker(CM-HCB)with DC power flow and fault current limitation abilities,as well as reduced component costs.The proposed CM-HCB topology enables the sharing of the main breaker branch(MB)and the energy dissipation branch,while the load commutation switches(LCSs)in the main branch are reused as power flow control components,enabling flexible regulation of power flow in multiple lines.Meanwhile,by reconstructing the current path during the fault process,the proposed CM-HCB can utilize the internal coupled inductor to limit the current rise rate at the initial stage of the fault,significantly reducing the requirement for breaking current.A detailed study on the topological structure,steady-state power flow regulation mechanism,transient fault isolation mechanism,control strategy and characteristic analysis of the proposed CM-HCB is presented.Then,a Matlab/Simulink-based meshed three-terminal DC grid simulation platform with the proposed CM-HCB is built.The results indicate that the proposed CM-HCB can not only achieve flexible power flow control during steady-state operation,but also obtain current rise limitation and fault isolation abilities under short-circuit fault conditions,verifying its correctness and effectiveness.Finally,a comparative economic analysis is conducted between the proposed CM-HCB and the other two existing solutions,confirming that its component sharing mechanism can significantly reduce the number of components,lower system costs,and improve component utilization.
基金supported by the National Natural Science Foundation of China(Grant Nos.12104190,12104189,12204312)the Natural Science Foundation of Jiangsu Province(Grant No.BK20210874)+2 种基金General project of Natural Science Research in Colleges And Universities of Jiangsu Province(Grant No.20KJB140008)the Jiangxi Provincial Natural Science Foundation(Grant Nos.20224BAB211014 and 20232BAB201042)Key Laboratory of Tian Qin Project(Sun Yat-sen University)。
文摘A scheme is proposed based on a Mach-Zehnder interferometer with high phase sensitivity,utilizing a two-mode squeezed coherent state,generated by four-wave mixing,as input.The phase sensitivity of this scheme easily surpasses the Heisenberg limit when intensity difference detection is applied.Under phase-matching conditions,the quantum Cramér-Rao bound significantly exceeds the Heisenberg limit.Additionally,the scheme exhibits robustness against photon loss.When compared with the modified SU(1,1)interferometer with two coherent state inputs,this approach demonstrates superior measurement sensitivity,evaluated through various detection methods and the quantum Cramér-Rao bound.This work holds potential applications in quantum metrology.
文摘The quality of cardiopulmonary resuscitation(CPR) significantly influences survival and neurological outcomes in patients with cardiac arrest(CA).Although mechanical chest compression devices and extracorporeal cardiopulmonary resuscitation(ECPR) have demonstrated some benefits,high-quality manual CPR remained the essential first step,particularly in resource-limited settings.In this study,we examined whether opportunities existed to improve manual CPR performance using preliminary data from our recent survey conducted in a province in western China.We aim to emphasize the importance of improving manual CPR quality before implementing advanced interventions.
基金funded by the National Natural Science Foundation of China(No.62364002)Key Scientific Research Projects of Universities in Henan Province(No.24A510014)+5 种基金Xinjiang-Changji Vocational Education Alliance Special Project(No.2050305)National Laboratory of Solid State Microstructures,Nanjing University(No.M36001)Jiangsu Key Laboratory of Optoelectronic Information Functional Materials,Nanjing University(No.ndgd2024005)Henan Province Higher Education College Student Innovation Training Program Project(No.202410478019)the Doctoral Research Initiation Fund Project,Zhoukou Normal University(No.ZKNUC2022018)the Natural Science Foundation Project of Xinjiang Uygur Autonomous Region(No.2022D01C006)。
文摘The porous NiO nanoplates modified with rGO nanosheets and SnO_(2)nanoparticles are developed for accurate and rapid ppb-level NO_(2)detection.The developed SnO_(2)/NiO/rGO sensor towards 50 ppm NO_(2)gas demonstrates an excellent gas-sensing response of 14.8 at 23℃,which is 3.03 times that of Ni O/rGO sensor(4.89)and 6.49 times that of NiO sensor(2.28),respectively.The developed SnO_(2)/NiO/rGO sensor exhibits faster response/recovery speed(12.7/32.8 s@5 ppm),with extra-low theoretical detection limit of 0.15 ppb at room temperature.More fascinatingly,our sensors indicate great sensitivity,outstanding repeatability and long-term stability for longer than 7 weeks.Additionally,it also suggests that 1℃and 1%relative humidity have the same effect on the SnO_(2)/NiO/rGO sensor signal as approximately 13 ppb and 7.0 ppb NO_(2)gas change,respectively.Such excellent properties are mainly attributed to the large surface-to-volume ratio,which provides active sites to NO_(2)gas spread,adsorption and diffusion on material surface in redox reaction.Moreover,the ternary heterojunctions formed by NiO,rGO and SnO_(2)may serve as highly conductive channels to accelerate carrier transfer and abundant oxygen vacancies to reduce the adsorption energy for O_(2)and NO_(2)gas,thus further improving performance of the sensors.
基金supported by the National Natural Science Foundation of China(22209006,21935001)the Natural Science Foundation of Shandong Province(ZR2022QE009)+1 种基金Fundamental Research Funds for the Central Universities(buctrc202307)the Beijing Natural Science Foundation(Z210016).
文摘Low-cost and high-safety aqueous Zn-I_(2) batteries attract extensive attention for large-scale energy storage systems.However,polyiodide shuttling and sluggish iodine conversion reactions lead to inferior rate capability and severe capacity decay.Herein,a three-dimensional polyaniline is wrapped by carboxylcarbon nanotubes(denoted as C-PANI)which is designed as a catalytic cathode to effectively boost iodine conversion with suppressed polyiodide shuttling,thereby improving Zn-I_(2) batteries.Specifically,carboxyl-carbon nanotubes serve as a proton reservoir for more protonated-NH+=sites in PANI chains,achieving a direct I0/I−reaction for suppressed polyiodide generation and Zn corrosion.Attributing to this“proton-iodine”regulation,catalytic protonated C-PANI strongly fixes electrolytic iodine species and stores proton ions simultaneously through reversible-N=/-NH^(+)-reaction.Therefore,the electrolytic Zn-I_(2) battery with C-PANI cathode exhibits an impressive capacity of 420 mAh g^(−1) and ultra-long lifespan over 40,000 cycles.Additionally,a 60 mAh pouch cell was assembled with excellent cycling stability after 100 cycles,providing new insights into exploring effective organocatalysts for superb Zn-halogen batteries.
基金supported by the Technology Project of State Grid(No.SGSNKYOOKJJS1501564)the National Key Basic Research Program of China(973 Program)(No.2015CB251005)
文摘The GaInSn liquid metal current limiter based on the fluid pinch effect has broad application prospects due to its particular properties. However, the limited rated current and abil- ity of power dissipation are the critical problems for its wide application. Firstly, the temperature distribution of the liquid metal current limiter （LMCL） was obtained by experiments with a rated current of 1 kA and the arc ignition phenomenon was observed with 1.5 kA, which indicates that the rated current is mainly limited by the arc rather than the high temperature compared to the traditional switchgears. Furthermore, an improved method is proposed by adding the paralleled pure resistance, impedance or another LMCL element to protect the setup from the fault energy concentration in the setup. The problem of a slower arc voltage increasing rate can be solved by adding a paralleled impedance with suitable parameters. Finally, the current limiting properties based on the improved method were investigated and the alternating oscillating current was found between two paralleled LMCL elements owing to their deviation of arc ignition in reality.
基金supported by the National Basic Research Program of China (2009CB724104)the National Natural Science Foundation of China (90716010)
文摘A novel class of weighted essentially nonoscillatory （WENO） schemes based on Hermite polynomi- als, termed as HWENO schemes, is developed and applied as limiters for high order discontinuous Galerkin （DG） method on triangular grids. The developed HWENO methodology utilizes high-order derivative information to keep WENO re- construction stencils in the von Neumann neighborhood. A simple and efficient technique is also proposed to enhance the smoothness of the existing stencils, making higher-order scheme stable and simplifying the reconstruction process at the same time. The resulting HWENO-based limiters are as compact as the underlying DG schemes and therefore easy to implement. Numerical results for a wide range of flow conditions demonstrate that for DG schemes of up to fourth order of accuracy, the designed HWENO limiters can simul- taneously obtain uniform high order accuracy and sharp, es- sentially non-oscillatory shock transition.
基金supported by the National Natural Science Foundation of China(Grants No.51679170,51379157,and 51439007)
文摘A two-dimensional （2D） dam-break flow numerical model was developed based on the finite-volume total variation diminishing （TVD） and monotone upstream-centered scheme for conservation laws （MUSCL）-Hancock scheme, which has second-order accuracy in both time and space. A Harten-Lax-van Leer-contact （HLLC） approximate Riemann solver was used to evaluate fluxes. The TVD MUSCL-Hancock numerical scheme utilizes slope limiters, such as the minmod, double minmod, superbee, van Albada, and van Leer limiters, to prevent spurious oscillations and maintain monotonicity near discontinuities. A comparative study of the impact of various slope limiters on the accuracy of the numerical flow model was conducted with several dam-break examples including wet and dry bed cases. The numerical results of the superbee and double minmod limiters agree better with the theoretical solution and have higher accuracy than other limiters in one-dimensional （1D） space. The ratio of the downstream water depth to the upstream water depth was used to select the proper slope limiter. For the 2D numerical model, the superbee limiter should not be used, owing to significant numerical dispersion.
基金the Equipment Foundation of Equipment Ministry of China(No.51421KG0152)
文摘A novel plasma limiter, in which the plasma is excited by surface wave, is presented. The breakdown time of some gases filled in the limiter were calculated as a function of gas pres- sure, ionization degree and density of seed electrons under low pressure （0.01 -1 Torr） and high pressure （10 -1000 Torr） cases. The results show that the limiter filled with Xe with a pressure of 0.9 Torr, seed electron density of 10^16 m^-3, and ionization degree of 10^-4, has a breakdown time of approximate 19.6 ns.
基金funded by the National Key Research and Development Program of China(No.2017YFE0301100)National Natural Science Foundation of China(Nos.11905138,11905148 and 11905254)+2 种基金the U.S.Dept.of Energy contract DE-AC02-09CH11466 and grant DESC0016553Users with Excellence Program of Hefei Science Center CAS(No.2020HSC-UE010)Interdisciplinary and Collaborative Teams of CAS。
文摘A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST tokamak.The results revealed that after a plasma operation of a few seconds,the layer became clear,which indicated a strong Li emission with a decrease in the limiter surface temperature.This emission resulted in a dense vapour around the limiter,and Li ions moved along the magnetic fleld to form a green shielding layer on the limiter.The plasma heat flux loaded on the limiter,measured by the probe installed on the limiter,was approximately 52%lower than that detected by a fast-reciprocating probe at the same radial position without the limiter in EAST.Additionally,approximately 42%of the parallel heat flux was dissipated directly with the enhanced Li radiation in the discharge with the liquid metal infused trenches(LIMIT)limiter.This observation revealed that the Li vapour layer exhibited an excellent shielding effect to liquid Li on plasma heat flux,which is a possible beneflt of liquid-plasma-facing components in future fusion devices.
基金supported by National Natural Science Foundation of China(Nos.51777025,52177131)the Interdisciplinary Program of the Wuhan National High Magnetic Field Center(No.WHMFC202130)Huazhong University of Science and Technology。
文摘The liquid metal current limiter(LMCL)is regarded as a viable solution for reducing the fault current in a power grid.But demonstrating the liquid metal arc plasma self-pinching process of the resistive wall,and reducing the erosion of the LMCL are challenging,not only theoretically,but also practically.In this work,a novel LMCL is designed with a resistive wall that can be connected to the current-limiting circuit inside the cavity.Specifically,a novel fault current limiter(FCL)topology is put forward where the novel LMCL is combined with a fast switch and current-limiting reactor.Further,the liquid metal self-pinch effect is modeled mathematically in three dimensions,and the gas-liquid two-phase dynamic diagrams under different short-circuit currents are obtained by simulation.The simulation results indicate that with the increase of current,the time for the liquid metal-free surface to begin depressing is reduced,and the position of the depression also changes.Different kinds of bubbles formed by the depressions gradually extend,squeeze,and break.With the increase of current,the liquid metal takes less time to break,but breaks still occur at the edge of the channel,forming arc plasma.Finally,relevant experiments are conducted for the novel FCL topology.The arcing process and current transfer process are analyzed in particular.Comparisons of the peak arc voltage,arcing time,current limiting efficiency,and electrode erosion are presented.The results demonstrate that the arc voltage of the novel FCL topology is reduced by more than 4.5times and the arcing time is reduced by more than 12%.The erosions of the liquid metal and electrodes are reduced.Moreover,the current limiting efficiency of the novel FCL topology is improved by 1%–5%.This work lays a foundation for the topology and optimal design of the LMCL.
