In this paper,we present a broadband,high-extinction-ratio,nonvolatile 2×2 Mach-Zehnder interfer⁃ometer(MZI)optical switch based on the phase change material Sb_(2)Se_(3).The insertion loss(IL)is 0.84 dB and the ...In this paper,we present a broadband,high-extinction-ratio,nonvolatile 2×2 Mach-Zehnder interfer⁃ometer(MZI)optical switch based on the phase change material Sb_(2)Se_(3).The insertion loss(IL)is 0.84 dB and the extinction ratio(ER)reaches 28.8 dB at the wavelength of 1550 nm.The 3 dB bandwidth is greater than 150 nm.Within the 3 dB bandwidth,the ER is greater than 20.3 dB and 16.3 dB at bar and cross states,respectively.The power consumption for crystallization and amorphization of Sb_(2)Se_(3) is 105.86 nJ and 49 nJ,respectively.The switch holds significant promise for optical interconnects and optical computing applications.展开更多
In this paper,a comprehensive evaluation on the silicon/silicon carbide(Si/SiC)hybrid switch is performed through experimental tests in terms of both electrical performance and robustness under extreme stresses.Based ...In this paper,a comprehensive evaluation on the silicon/silicon carbide(Si/SiC)hybrid switch is performed through experimental tests in terms of both electrical performance and robustness under extreme stresses.Based on the optional turn-on and turn-off delay times under the efficiency control mode obtained from the double-pulse test(DPT),both nondestructive and destructive single-pulse avalanche tests are conducted on the Si/SiC hybrid switch as well as on the two discrete device branches inside the hybrid switch.In addition,the avalanche voltage,critical avalanche energy,and peak avalanche current,which intrinsically characterize the unclamped-inductive-switching(UIS)avalanche characteristics,are carefully examined.In this way,the physical factors dominating the UIS characteristics of the hybrid switch,thus limiting its single-pulse avalanche withstand capability,are specifically and comprehensively identified;the underlying physical mechanisms are analyzed and revealed in depth,and how the gate control sequence affects the UIS characteristics of the hybrid switch is extensively investigated.We additionally carry out short-circuit(SC)tests under the fault-under-load(FUL)condition and perform a parallel in-depth analysis to experimentally determine which branch dominates the SC withstand capability of the hybrid switch.Our experimental study indicates that,for both SC robustness and single-pulse avalanche capability,the limiting factor is a single device branch among the two parallel discrete devices,and the UIS behavior is sensitive to the variation of the gate turn-off delay time Toff_delay.The study conducted in this paper not only provides deep academic insights into the electrical performance and reliability of the Si/SiC hybrid switch,but also offers fundamental theoretical principles and technical evidence to support its more efficient and long-term reliable applications of the hybrid switch in the industrial fields.展开更多
A stochastic predator-prey system with Markov switching is explored.We have developed a new chasing technique to efficiently solve the Fokker-Planck-Kolmogorov and backward Kolmogorov equations.Dynamic balance and rel...A stochastic predator-prey system with Markov switching is explored.We have developed a new chasing technique to efficiently solve the Fokker-Planck-Kolmogorov and backward Kolmogorov equations.Dynamic balance and reliability of the switching system are evaluated via stationary probability density function and first-passage failure theory,taking into account factors such as switching frequencies,noise intensities,and initial conditions.Results reveal that Markov switching leads to stochastic P-bifurcation,enhancing dynamic balance and reducing white-noise-induced oscillations.But frequent switching can heighten initial value dependence,harming reliability.Further,the influence of the subsystem on the switching system is not proportional to its action probabilities.Monte Carlo simulations validate the findings,offering an in-depth exploration of these dynamics.展开更多
Coherent perfect absorption(CPA)and coherent perfect transmission(CPT)are two extreme states arising from the manipulation of optical fields.Generally,CPA and CPT occur under different input-field phases.Therefore,we ...Coherent perfect absorption(CPA)and coherent perfect transmission(CPT)are two extreme states arising from the manipulation of optical fields.Generally,CPA and CPT occur under different input-field phases.Therefore,we propose a scheme to realize an all-optical switch based on phase-dependent CPA–CPT conversion.In our proposal,the CPT state and the CPA state are treated as the on state and the off state,respectively.Consequently,the efficiency of this all-optical switch can reach the maximum value of 1.With the introduction of an incoherent pump field,the CPA state can be achieved under a weaker input probe field or can be converted into a CPT state.The results show that the optical switch can operate with weaker fields and can be further optimized by the application of an incoherent field.展开更多
This paper focuses on the leader-following positive consensus problems of heterogeneous switched multi-agent systems.First,a state-feedback controller with dynamic compensation is introduced to achieve positive consen...This paper focuses on the leader-following positive consensus problems of heterogeneous switched multi-agent systems.First,a state-feedback controller with dynamic compensation is introduced to achieve positive consensus under average dwell time switching.Then sufficient conditions are derived to guarantee the positive consensus.The gain matrices of the control protocol are described using a matrix decomposition approach and the corresponding computational complexity is reduced by resorting to linear programming and co-positive Lyapunov functions.Finally,two numerical examples are provided to illustrate the results obtained.展开更多
Field-effect nanofluidic transistors(FENTs),biomimicking the structure and functionality of neuron,act as biological transistors with the ability to gate switching responses to external stimuli.The switching ratio has...Field-effect nanofluidic transistors(FENTs),biomimicking the structure and functionality of neuron,act as biological transistors with the ability to gate switching responses to external stimuli.The switching ratio has been verified to evaluate the performance of FENTs,but until recently,the response time,another crucial indicator,has been ignored.Employing finite-element method,we investigated the relationship among gate charge,switching ratio and response time by divisionally manipulating gate charge,including entrance surface and the surface of confinement space,for ion transport to optimize switching capability.The dual-split gate charge on FENTs exhibits synergistic effect on switching response.Based on the two regional gate charge on FENTs,multivalence ions in lower concentration,high aspect ratio and single channel show higher switching ratio but longer response time compared to monovalent ions.The findings highlight the necessity of balancing these two signals in FENTs and offer insights for optimizing their design and expanding applications to dual-signal-detection iontronics.展开更多
The development of electrocatalysts that both work effectively at industrial current density and resist chloride ion(Cl^(-))corrosion remains a key challenge for hydrogen production from Cl^(-)-rich alkaline water.Her...The development of electrocatalysts that both work effectively at industrial current density and resist chloride ion(Cl^(-))corrosion remains a key challenge for hydrogen production from Cl^(-)-rich alkaline water.Herein,we report a CrO_(x)-engineered nickel-based oxide catalyst(FeCoCrO_(x)/NF)that achieves exceptional activity and stability through a dual-functional interfacial mechanism.Combing in situ Raman spectroscopy,18O isotopic labeling,and electrochemical analysis,we demonstrate that the oxygen evolution reaction follows a lattice oxygen-mediated mechanism.The CrO_(x)layer selectively adsorbs hydroxide ions,forming a dynamic interfacial barrier that electrostatically repels Cl^(-)ingress,thereby mitigating Cl^(-)corrosion.Through enthalpy-based analysis,we demonstrate that electronic redistribution via Cr-O-Fe bonding increases the vacancy formation energy of Fe,thereby suppressing its dissolution.In alkaline electrolyte containing 0.5 M Cl^(-)(1.0 M KOH),the catalyst is operating continuously for 1400 h at an industrial current density of 1000 mA cm^(-2).Furthermore,the catalyst retains 99.5%of its initial activity under fluctuating current density(100-1000 mA cm^(-2)),demonstrating robustness required for industrial electrolyzers.This study establishes a paradigm for designing corrosion-resistant electrocatalysts through the synergistic modulation of interfacial ion selectivity and bulk lattice oxygen activation,advancing the application of green hydrogen production in Cl^(-)-rich alkaline water.展开更多
Soft machines harness material-level physical intelligence to perform adaptive tasks,enabling advancements in biomedical and human-machine interaction fields.Soft switches are the basic building blocks to achieve inte...Soft machines harness material-level physical intelligence to perform adaptive tasks,enabling advancements in biomedical and human-machine interaction fields.Soft switches are the basic building blocks to achieve intelligent functions like autonomous decisions and mechanical computation.However,current soft switches suffer from complex fabrication processes,limited performance,and a lack of multimodal control,which hinder their practical application and the realization of machine intelligence.Herein,by harnessing the unique self-pinch and self-healing effects of the gallium-based liquid metals(LMs),we describe a soft high-performance electric switch composed of an LM line encapsulated within an elastomer.Applying pressure to deform the LM switch can increase local current density,leading to the electromagnetic self-pinch effect for switching off.After releasing pressure,the LM can spontaneously heal with the elastic recovery of the elastomer for switching on.This LM switch shows comprehensive advantages,including a compact design(0.5 mm×1.5 mm×10 mm),good stretchability(100%),high on/off ratio(~10^(9)),rapid response time(<100 ms),and excellent durability(>12000 cycles).Moreover,the LM switches enable multiple control modes,including magnetic and optical stimulation,through the integration of responsive materials.We demonstrate various LM switch-enabled functional soft machines,such as an interactive flexible gripper,a self-oscillating soft crawler,and wearable logic gates.This work will open new avenues for the application of LM in intelligent soft machines and advanced wearable electronics.展开更多
Self-trapped excitons(STEs),known for their unique radiative properties,have been harnessed in diverse photonic devices;however,their comprehensive understanding and manipulation remain elusive.In this study,we presen...Self-trapped excitons(STEs),known for their unique radiative properties,have been harnessed in diverse photonic devices;however,their comprehensive understanding and manipulation remain elusive.In this study,we present novel experimental and theoretical evidence revealing the hybrid nature and optical tunability of STE state in Cs_(2)Ag_(0.4)Na_(0.6)InCl_(6).The detection of the Fano resonance in laser energy-dependent Raman and photoluminescence spectra indicates the emergence of an exciton-phonon hybrid state,arising from robust quantum interference between the discrete phonon and continuum exciton states.Moreover,we demonstrate continuous tuning of this hybrid state with the energy and intensity of the laser field.These findings lay the foundation for a comprehensive understanding of the nature of STE and their potential for state control.展开更多
High Speed on/off Valve(HSV)is an essential component in Aerospace Digital Hydraulic Systems(ADHS),which impose stringent requirements on the dynamic performance and reliability of HSV due to the extreme application e...High Speed on/off Valve(HSV)is an essential component in Aerospace Digital Hydraulic Systems(ADHS),which impose stringent requirements on the dynamic performance and reliability of HSV due to the extreme application environments.However,the faster dynamic leads to increased impact between the spool and valve body,causing severe vibration and wear,which creates a conflict between rapid dynamic and high reliability.To address this problem,a Pre-Excitation Soft Switching Control(PESSC)with both pre-excitation and reverse deceleration functionalities is proposed.The initial current is optimized through pre-excitation to accelerate the opening time,while the application of reverse voltage hastens the decline of electromagnetic force,thereby reducing the spool velocity.The PESSC simultaneously achieves both faster dynamic performance and smaller impact velocity.Moreover,the optimal deceleration voltage parameters are obtained through multi-objective optimization.Experimental results demonstrate that the optimized PESSC shortens the opening time from 2.22 ms to 1.65 ms,reduces the impact velocity by 58.3%,and lowers wear by 55.4%.These findings underline the huge potential of PESSC in enhancing the dynamic performance and reliability of HSVs,offering promising applications in aerospace.展开更多
Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improv...Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.展开更多
This paper is concerned with adaptive consensus tracking control of nonlinear multi-agent systems with actuator faults and unknown nonidentical control directions under double semi-Markovian switching topologies.Consi...This paper is concerned with adaptive consensus tracking control of nonlinear multi-agent systems with actuator faults and unknown nonidentical control directions under double semi-Markovian switching topologies.Considering the complex working environment and the stability differences in communication links between leaders and followers,a double semi-Markov process is first introduced to describe the random switching of communication topologies in the leader-follower structure.In order to address challenges from the unknown nonidentical control directions and partial loss of effectiveness actuator faults,a completely independent parameter is introduced into the Nussbaum function to overcome the inherent obstacle of mutual cancellation and avoid the rapid growth rate.Considering only the state information of agents is transmitted among the agents,an adaptive distributed fault-tolerant consensus tracking control is proposed based on the double semi-Markovian switching topologies using the designed Nussbaum function.Furthermore,the stability of the closed-loop nonlinear multi-agent systems is analyzed using contradiction argument and Lyapunov theorem,from which the asymptotic consensus tracking in mean square sense can be obtained.A numerical simulation example is provided to verify the effectiveness of the proposed algorithm.展开更多
The enhancement of perpendicular magnetic anisotropy(PMA)is critical for the continuous growth of magnetic memory density.Material systems that possess high interfacial PMA typically involve strong spin-orbit coupling...The enhancement of perpendicular magnetic anisotropy(PMA)is critical for the continuous growth of magnetic memory density.Material systems that possess high interfacial PMA typically involve strong spin-orbit coupling(SOC)or transition metal/oxide interfaces.In contrast,the role of 3d light metals in enhancing the interfacial PMA has been less investigated.This study demonstrated that the insertion of a few atomic Cr layers into Pt/Co/Pt/Ta heterostructures with Cr between the 1 atomic Pt layer and the 3 nm Ta overlayer enhanced the effective PMA energy(K_(eff))by a factor of 4.First-principles calculations revealed that the underlying mechanism originated from Cr-Pt d-orbital hybridization,leading to a corresponding orbital redistribution and significantly increasing the magnetic anisotropy energy.The progressive reduction in the spin-orbit torque(SOT)efficiency with increasing Cr thickness might stem from the enhanced orbital Rashba–Edelstein effect at the Pt/Cr interface.Furthermore,the wedging of a few atomic Cr layers caused the robust field-free SOT switching of perpendicular magnetization,which was due to the lateral PMA gradients enabled by the strong dependence of the PMA on the Cr thickness.The results provide a method for interfacial PMA enhancement by d-orbital hybridization of 3d–5d electrons and an alternative to field-free SOT switching towards low-power and high-density memory applications.展开更多
Novel 2×2 torsion-mirror optical switch arrays are fabricated by using the mixed micromachining based on the surface and bulk silicon microelectronics,then are investigated electromechanically in applied direct a...Novel 2×2 torsion-mirror optical switch arrays are fabricated by using the mixed micromachining based on the surface and bulk silicon microelectronics,then are investigated electromechanically in applied direct and alternating electric fields.When the thickness of the elastic torsion beams suspending the aluminum coated polysilicon micro-mirrors of the switches in the arrays is about 1μm,the electrostatic yielding voltages for driving the mirrors to achieve their ON-state are in the range of 270～290V,and the minimum holding voltages for mirrors ON-state are found as 55V or so.Theoretical analysis manifests that the yielding voltage is more sensitive to beam thickness than other design parameters do about the torsion-mirror switch structures.The lifetime can reach 10 8 times.The estimated shortest switching time of the switches at least lasts for less than 2ms.The force analysis on the two kinds of new fiber self-holding structures integrated monolithically in the chip of the optical switch arrays indicates that the structures can feature self-fixing and self-aligning of optical fibers.展开更多
MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap el...MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap electric field is superposed at the trigger gap to let the electrons in its spark channel also become initial electrons, is proposed and tested. The design idea is: as electrons in the spark channel of the trigger gap always exist after its breakdown, the injection time of pre-ionization should have a more negligible effect on reducing the switch jitter. The experiment results under pulses with a rise time of ~100 ns support the above assumptions.When the operating voltage is from ~300 to ~800 kV and the self-triggering time is ~45% to~75% of the peak time, the breakdown time delay jitter is less than 2 ns, and the breakdown voltage jitter is smaller than 1.25%. Under specific self-triggering time, the breakdown time delay jitter is less than 1.5 ns, and the breakdown voltage jitter is smaller than 0.8%.展开更多
In this work,the influence of the electrode surface roughness on the self-breakdown gas switch is investigated by physical analysis,computer simulation and experiment.Cu-W electrodes of different surface roughness wer...In this work,the influence of the electrode surface roughness on the self-breakdown gas switch is investigated by physical analysis,computer simulation and experiment.Cu-W electrodes of different surface roughness were tested under the conditions of a pulse repetitive frequency of50 Hz,self-breakdown voltage of~30 kV,and peak current of~2 k A for~93000 shots(the total charge transferred was~15 C).The coefficients of variation of the self-breakdown voltage of Cu-W 0.8,Cu-W 3.2 and Cu-W 12.5 electrodes were~2.95%,~1.62%and~1.16%,respectively.With the increase of electrode roughness,the erosion area decreased continuously,indicating that the breakdown positions were more stable and the coefficient of variation of breakdown voltage decreased.The method showed that decreasing the coefficient of variation of the self-breakdown voltage by increasing the surface roughness of electrode greatly improves the stability of the self-breakdown switch,which is significant for their application in compact highpower pulse power devices over a long time with stable operation.展开更多
Combining the self-stimulated Raman scattering technology and saturable absorber of Cr^(4+):YAG, a 1.17 μm c-cut Nd:GdVO_4 picosecond Q-switched laser is demonstrated in this paper. With an incident pump power of 10 ...Combining the self-stimulated Raman scattering technology and saturable absorber of Cr^(4+):YAG, a 1.17 μm c-cut Nd:GdVO_4 picosecond Q-switched laser is demonstrated in this paper. With an incident pump power of 10 W, the Q-switched laser with average power of 430 mW for 1.17 μm, pulse width of 270 ps, repetition rate of 13 kHz and the first order Stokes conversion efficiency of 4.3% is obtained. The Q-switched pulse width can be the narrowest in our research. In addition, the yellow laser at 0.58 μm is also achieved by using the LiB_3O_5 frequency doubling crystal.展开更多
基金Supported by the National Natural Science Foundation of China(62204250)Autonomous deployment project of State Key Laboratory of Materials for Integrated Circuits(SKLJC-Z2024-A05).
文摘In this paper,we present a broadband,high-extinction-ratio,nonvolatile 2×2 Mach-Zehnder interfer⁃ometer(MZI)optical switch based on the phase change material Sb_(2)Se_(3).The insertion loss(IL)is 0.84 dB and the extinction ratio(ER)reaches 28.8 dB at the wavelength of 1550 nm.The 3 dB bandwidth is greater than 150 nm.Within the 3 dB bandwidth,the ER is greater than 20.3 dB and 16.3 dB at bar and cross states,respectively.The power consumption for crystallization and amorphization of Sb_(2)Se_(3) is 105.86 nJ and 49 nJ,respectively.The switch holds significant promise for optical interconnects and optical computing applications.
基金supported in part by the Anhui Provincial Natural Science Foundation Youth Project(Category C)under Grant No.2508085QE184the Opening Project of Key Laboratory of Power Electronics and Motion Control of Anhui Higher Education Institutions under Grant No.PEMC24004+1 种基金the Anhui University of Technology Young Teachers Research Fund under Grant No.QZ202412the Scientific Research Startup Fund for Introduced Talents of Anhui University of Technology under Grant No.QD202340.
文摘In this paper,a comprehensive evaluation on the silicon/silicon carbide(Si/SiC)hybrid switch is performed through experimental tests in terms of both electrical performance and robustness under extreme stresses.Based on the optional turn-on and turn-off delay times under the efficiency control mode obtained from the double-pulse test(DPT),both nondestructive and destructive single-pulse avalanche tests are conducted on the Si/SiC hybrid switch as well as on the two discrete device branches inside the hybrid switch.In addition,the avalanche voltage,critical avalanche energy,and peak avalanche current,which intrinsically characterize the unclamped-inductive-switching(UIS)avalanche characteristics,are carefully examined.In this way,the physical factors dominating the UIS characteristics of the hybrid switch,thus limiting its single-pulse avalanche withstand capability,are specifically and comprehensively identified;the underlying physical mechanisms are analyzed and revealed in depth,and how the gate control sequence affects the UIS characteristics of the hybrid switch is extensively investigated.We additionally carry out short-circuit(SC)tests under the fault-under-load(FUL)condition and perform a parallel in-depth analysis to experimentally determine which branch dominates the SC withstand capability of the hybrid switch.Our experimental study indicates that,for both SC robustness and single-pulse avalanche capability,the limiting factor is a single device branch among the two parallel discrete devices,and the UIS behavior is sensitive to the variation of the gate turn-off delay time Toff_delay.The study conducted in this paper not only provides deep academic insights into the electrical performance and reliability of the Si/SiC hybrid switch,but also offers fundamental theoretical principles and technical evidence to support its more efficient and long-term reliable applications of the hybrid switch in the industrial fields.
基金Project supported by the National Natural Science Foundation of China(Grant No.12472033)。
文摘A stochastic predator-prey system with Markov switching is explored.We have developed a new chasing technique to efficiently solve the Fokker-Planck-Kolmogorov and backward Kolmogorov equations.Dynamic balance and reliability of the switching system are evaluated via stationary probability density function and first-passage failure theory,taking into account factors such as switching frequencies,noise intensities,and initial conditions.Results reveal that Markov switching leads to stochastic P-bifurcation,enhancing dynamic balance and reducing white-noise-induced oscillations.But frequent switching can heighten initial value dependence,harming reliability.Further,the influence of the subsystem on the switching system is not proportional to its action probabilities.Monte Carlo simulations validate the findings,offering an in-depth exploration of these dynamics.
基金supported by the National Natural Science Foundation of China(Grants Nos.12304405,12275203,and 12075176)the Natural Science Foundation of Shaanxi Provincial Department of Education(Grant No.23JK0483)+2 种基金the Natural Science Basic Research Program of Shaanxi(Grant Nos.2024JC-YBMS-521 and 2024JC-YBMS-039)the 2022 Shaanxi University Youth Innovation Team Project(Grant No.K20220186)the College Students’Innovative Entrepreneurial Training Plan Program of Shaanxi(Grant No.S202410702178)。
文摘Coherent perfect absorption(CPA)and coherent perfect transmission(CPT)are two extreme states arising from the manipulation of optical fields.Generally,CPA and CPT occur under different input-field phases.Therefore,we propose a scheme to realize an all-optical switch based on phase-dependent CPA–CPT conversion.In our proposal,the CPT state and the CPA state are treated as the on state and the off state,respectively.Consequently,the efficiency of this all-optical switch can reach the maximum value of 1.With the introduction of an incoherent pump field,the CPA state can be achieved under a weaker input probe field or can be converted into a CPT state.The results show that the optical switch can operate with weaker fields and can be further optimized by the application of an incoherent field.
基金supported by the National Natural Science Foundation of China(62463007,62463005)the Natural Science Foundation of Hainan Province(625RC710,625MS047)+1 种基金the System Control and Information Processing Education Ministry Key Laboratory Open Funding,China(Scip20240119)the Science Research Funding of Hainan University,China(KYQD(ZR)22180,KYQD(ZR)23180).
文摘This paper focuses on the leader-following positive consensus problems of heterogeneous switched multi-agent systems.First,a state-feedback controller with dynamic compensation is introduced to achieve positive consensus under average dwell time switching.Then sufficient conditions are derived to guarantee the positive consensus.The gain matrices of the control protocol are described using a matrix decomposition approach and the corresponding computational complexity is reduced by resorting to linear programming and co-positive Lyapunov functions.Finally,two numerical examples are provided to illustrate the results obtained.
基金supported by the Natural Science Foundation of Guangdong Province,China (No.2025A1515011654)the National Natural Science Foundation of China (No.22090053)+3 种基金the Fundamental Research Funds for National Universities,China University of Geosciences (Wuhan)support from the program of China Scholarships Council (No.202406410155)Young Elite Scientists Sponsorship Program by CAST-Doctoral Student Special Plansupport from the S&T Special Program of Huzhou (No.2024GZ07)。
文摘Field-effect nanofluidic transistors(FENTs),biomimicking the structure and functionality of neuron,act as biological transistors with the ability to gate switching responses to external stimuli.The switching ratio has been verified to evaluate the performance of FENTs,but until recently,the response time,another crucial indicator,has been ignored.Employing finite-element method,we investigated the relationship among gate charge,switching ratio and response time by divisionally manipulating gate charge,including entrance surface and the surface of confinement space,for ion transport to optimize switching capability.The dual-split gate charge on FENTs exhibits synergistic effect on switching response.Based on the two regional gate charge on FENTs,multivalence ions in lower concentration,high aspect ratio and single channel show higher switching ratio but longer response time compared to monovalent ions.The findings highlight the necessity of balancing these two signals in FENTs and offer insights for optimizing their design and expanding applications to dual-signal-detection iontronics.
基金supported by the National Nature Science Foundation of China under Grant No.22269021the Tianshan Talent Project of Xinjiang Uygur Autonomous Region:2023TSYCQNTJ0039the Open project of Key Laboratory in Xinjiang Uygur Autonomous Region of China:2023D04027。
文摘The development of electrocatalysts that both work effectively at industrial current density and resist chloride ion(Cl^(-))corrosion remains a key challenge for hydrogen production from Cl^(-)-rich alkaline water.Herein,we report a CrO_(x)-engineered nickel-based oxide catalyst(FeCoCrO_(x)/NF)that achieves exceptional activity and stability through a dual-functional interfacial mechanism.Combing in situ Raman spectroscopy,18O isotopic labeling,and electrochemical analysis,we demonstrate that the oxygen evolution reaction follows a lattice oxygen-mediated mechanism.The CrO_(x)layer selectively adsorbs hydroxide ions,forming a dynamic interfacial barrier that electrostatically repels Cl^(-)ingress,thereby mitigating Cl^(-)corrosion.Through enthalpy-based analysis,we demonstrate that electronic redistribution via Cr-O-Fe bonding increases the vacancy formation energy of Fe,thereby suppressing its dissolution.In alkaline electrolyte containing 0.5 M Cl^(-)(1.0 M KOH),the catalyst is operating continuously for 1400 h at an industrial current density of 1000 mA cm^(-2).Furthermore,the catalyst retains 99.5%of its initial activity under fluctuating current density(100-1000 mA cm^(-2)),demonstrating robustness required for industrial electrolyzers.This study establishes a paradigm for designing corrosion-resistant electrocatalysts through the synergistic modulation of interfacial ion selectivity and bulk lattice oxygen activation,advancing the application of green hydrogen production in Cl^(-)-rich alkaline water.
基金financial support from the Natural Science Foundation of Jiangsu Province(BK20220859)the Jiangsu Provincial Scientific Research Center of Applied Mathematics(BK20233002)+2 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_0473)the SEU Innovation Capability Enhancement Plan for Doctoral Students(CXJH_SEU 24144)supported by Open Research Fund of State Key Laboratory of Analytical Chemistry for Life Science,School of Chemistry and Chemical Engineering,Nanjing University。
文摘Soft machines harness material-level physical intelligence to perform adaptive tasks,enabling advancements in biomedical and human-machine interaction fields.Soft switches are the basic building blocks to achieve intelligent functions like autonomous decisions and mechanical computation.However,current soft switches suffer from complex fabrication processes,limited performance,and a lack of multimodal control,which hinder their practical application and the realization of machine intelligence.Herein,by harnessing the unique self-pinch and self-healing effects of the gallium-based liquid metals(LMs),we describe a soft high-performance electric switch composed of an LM line encapsulated within an elastomer.Applying pressure to deform the LM switch can increase local current density,leading to the electromagnetic self-pinch effect for switching off.After releasing pressure,the LM can spontaneously heal with the elastic recovery of the elastomer for switching on.This LM switch shows comprehensive advantages,including a compact design(0.5 mm×1.5 mm×10 mm),good stretchability(100%),high on/off ratio(~10^(9)),rapid response time(<100 ms),and excellent durability(>12000 cycles).Moreover,the LM switches enable multiple control modes,including magnetic and optical stimulation,through the integration of responsive materials.We demonstrate various LM switch-enabled functional soft machines,such as an interactive flexible gripper,a self-oscillating soft crawler,and wearable logic gates.This work will open new avenues for the application of LM in intelligent soft machines and advanced wearable electronics.
基金funding support from the National Natural Science Foundation of China(Grant No.12525405)funding support from the National Natural Science Foundation of China(Grant No.12393831)the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-120)。
文摘Self-trapped excitons(STEs),known for their unique radiative properties,have been harnessed in diverse photonic devices;however,their comprehensive understanding and manipulation remain elusive.In this study,we present novel experimental and theoretical evidence revealing the hybrid nature and optical tunability of STE state in Cs_(2)Ag_(0.4)Na_(0.6)InCl_(6).The detection of the Fano resonance in laser energy-dependent Raman and photoluminescence spectra indicates the emergence of an exciton-phonon hybrid state,arising from robust quantum interference between the discrete phonon and continuum exciton states.Moreover,we demonstrate continuous tuning of this hybrid state with the energy and intensity of the laser field.These findings lay the foundation for a comprehensive understanding of the nature of STE and their potential for state control.
基金supported in part by the “Pioneer”and “Leading Goose”R&D Program of Zhejiang Province(Nos.2022C01132 and 2022C01122)the National Natural Science Foundation of China(No.52005441)+3 种基金the Young Elite Scientist Sponsorship Program by CAST(No.20222024QNRC001)the State Key Laboratory of Mechanical System and Vibration,China(No.MSV202316)the Fundamental Research Funds for the Provincial Universities of Zhejiang,China(RF-A2023007)the Research Project of ZJUT,China(No.GYY-ZH-2023075)。
文摘High Speed on/off Valve(HSV)is an essential component in Aerospace Digital Hydraulic Systems(ADHS),which impose stringent requirements on the dynamic performance and reliability of HSV due to the extreme application environments.However,the faster dynamic leads to increased impact between the spool and valve body,causing severe vibration and wear,which creates a conflict between rapid dynamic and high reliability.To address this problem,a Pre-Excitation Soft Switching Control(PESSC)with both pre-excitation and reverse deceleration functionalities is proposed.The initial current is optimized through pre-excitation to accelerate the opening time,while the application of reverse voltage hastens the decline of electromagnetic force,thereby reducing the spool velocity.The PESSC simultaneously achieves both faster dynamic performance and smaller impact velocity.Moreover,the optimal deceleration voltage parameters are obtained through multi-objective optimization.Experimental results demonstrate that the optimized PESSC shortens the opening time from 2.22 ms to 1.65 ms,reduces the impact velocity by 58.3%,and lowers wear by 55.4%.These findings underline the huge potential of PESSC in enhancing the dynamic performance and reliability of HSVs,offering promising applications in aerospace.
基金the foundation of Guangdong Engineering Technology Research Center for Hydrogen Energy and Fuel Cells,the Guangdong Provincial Department of Education Innovation Project(No.2022KQNCX056)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515110354 and 2021A1515110582)。
文摘Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.
基金supported by the National Natural Science Foundation of China(62333011,62020106003)the Natural Science Foundation of Jiangsu Province of China(BK20222012)+1 种基金the Fundamental Research Funds for the Central Universities(NE2024005)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_0594)。
文摘This paper is concerned with adaptive consensus tracking control of nonlinear multi-agent systems with actuator faults and unknown nonidentical control directions under double semi-Markovian switching topologies.Considering the complex working environment and the stability differences in communication links between leaders and followers,a double semi-Markov process is first introduced to describe the random switching of communication topologies in the leader-follower structure.In order to address challenges from the unknown nonidentical control directions and partial loss of effectiveness actuator faults,a completely independent parameter is introduced into the Nussbaum function to overcome the inherent obstacle of mutual cancellation and avoid the rapid growth rate.Considering only the state information of agents is transmitted among the agents,an adaptive distributed fault-tolerant consensus tracking control is proposed based on the double semi-Markovian switching topologies using the designed Nussbaum function.Furthermore,the stability of the closed-loop nonlinear multi-agent systems is analyzed using contradiction argument and Lyapunov theorem,from which the asymptotic consensus tracking in mean square sense can be obtained.A numerical simulation example is provided to verify the effectiveness of the proposed algorithm.
基金supported by the “Pioneer” and “Leading Goose” R&D Program of Zhejiang Province (Grant No.2022C01053)the National Natural Science Foundation of China (Grant No.62293493)the Natural Science Foundation of Zhejiang Province,China (Grant No.LQ21A050001)。
文摘The enhancement of perpendicular magnetic anisotropy(PMA)is critical for the continuous growth of magnetic memory density.Material systems that possess high interfacial PMA typically involve strong spin-orbit coupling(SOC)or transition metal/oxide interfaces.In contrast,the role of 3d light metals in enhancing the interfacial PMA has been less investigated.This study demonstrated that the insertion of a few atomic Cr layers into Pt/Co/Pt/Ta heterostructures with Cr between the 1 atomic Pt layer and the 3 nm Ta overlayer enhanced the effective PMA energy(K_(eff))by a factor of 4.First-principles calculations revealed that the underlying mechanism originated from Cr-Pt d-orbital hybridization,leading to a corresponding orbital redistribution and significantly increasing the magnetic anisotropy energy.The progressive reduction in the spin-orbit torque(SOT)efficiency with increasing Cr thickness might stem from the enhanced orbital Rashba–Edelstein effect at the Pt/Cr interface.Furthermore,the wedging of a few atomic Cr layers caused the robust field-free SOT switching of perpendicular magnetization,which was due to the lateral PMA gradients enabled by the strong dependence of the PMA on the Cr thickness.The results provide a method for interfacial PMA enhancement by d-orbital hybridization of 3d–5d electrons and an alternative to field-free SOT switching towards low-power and high-density memory applications.
文摘Novel 2×2 torsion-mirror optical switch arrays are fabricated by using the mixed micromachining based on the surface and bulk silicon microelectronics,then are investigated electromechanically in applied direct and alternating electric fields.When the thickness of the elastic torsion beams suspending the aluminum coated polysilicon micro-mirrors of the switches in the arrays is about 1μm,the electrostatic yielding voltages for driving the mirrors to achieve their ON-state are in the range of 270～290V,and the minimum holding voltages for mirrors ON-state are found as 55V or so.Theoretical analysis manifests that the yielding voltage is more sensitive to beam thickness than other design parameters do about the torsion-mirror switch structures.The lifetime can reach 10 8 times.The estimated shortest switching time of the switches at least lasts for less than 2ms.The force analysis on the two kinds of new fiber self-holding structures integrated monolithically in the chip of the optical switch arrays indicates that the structures can feature self-fixing and self-aligning of optical fibers.
文摘MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap electric field is superposed at the trigger gap to let the electrons in its spark channel also become initial electrons, is proposed and tested. The design idea is: as electrons in the spark channel of the trigger gap always exist after its breakdown, the injection time of pre-ionization should have a more negligible effect on reducing the switch jitter. The experiment results under pulses with a rise time of ~100 ns support the above assumptions.When the operating voltage is from ~300 to ~800 kV and the self-triggering time is ~45% to~75% of the peak time, the breakdown time delay jitter is less than 2 ns, and the breakdown voltage jitter is smaller than 1.25%. Under specific self-triggering time, the breakdown time delay jitter is less than 1.5 ns, and the breakdown voltage jitter is smaller than 0.8%.
基金Huxiang Youth Talent Support Program(No.2020RC3030)State Key Laboratory of Pulsed Power Laser Technology(No.SK2021ZR02)。
文摘In this work,the influence of the electrode surface roughness on the self-breakdown gas switch is investigated by physical analysis,computer simulation and experiment.Cu-W electrodes of different surface roughness were tested under the conditions of a pulse repetitive frequency of50 Hz,self-breakdown voltage of~30 kV,and peak current of~2 k A for~93000 shots(the total charge transferred was~15 C).The coefficients of variation of the self-breakdown voltage of Cu-W 0.8,Cu-W 3.2 and Cu-W 12.5 electrodes were~2.95%,~1.62%and~1.16%,respectively.With the increase of electrode roughness,the erosion area decreased continuously,indicating that the breakdown positions were more stable and the coefficient of variation of breakdown voltage decreased.The method showed that decreasing the coefficient of variation of the self-breakdown voltage by increasing the surface roughness of electrode greatly improves the stability of the self-breakdown switch,which is significant for their application in compact highpower pulse power devices over a long time with stable operation.
基金supported by the National Natural Science Foundation of China(No.61108021)the Fundamental Research Funds for the Central Universities(Nos.2013JBM091 and S16JB00010)
文摘Combining the self-stimulated Raman scattering technology and saturable absorber of Cr^(4+):YAG, a 1.17 μm c-cut Nd:GdVO_4 picosecond Q-switched laser is demonstrated in this paper. With an incident pump power of 10 W, the Q-switched laser with average power of 430 mW for 1.17 μm, pulse width of 270 ps, repetition rate of 13 kHz and the first order Stokes conversion efficiency of 4.3% is obtained. The Q-switched pulse width can be the narrowest in our research. In addition, the yellow laser at 0.58 μm is also achieved by using the LiB_3O_5 frequency doubling crystal.
