This paper presents a photonic crystal(PhC)line-defect slow-light waveguide modified by resonant rings.We introduce resonant rings into the line defect,constructing a slow-light waveguide with high normalized delay ba...This paper presents a photonic crystal(PhC)line-defect slow-light waveguide modified by resonant rings.We introduce resonant rings into the line defect,constructing a slow-light waveguide with high normalized delay bandwidth product(NDBP)and low group velocity dispersion(GVD).We simulate,analyze,and optimize the structural parameters of this slow-light waveguide using the finite difference time domain(FDTD)method,theoretically achieving a maximum group index of 3.7,maximum bandwidth of 15.6 nm,and maximum NDBP of 0.4416 for slow-light effect.The resonant ring-modified PhC slow-light waveguide designed in this paper exhibits GVD lower than the order of 10^(−20)s^(2)/m over a normalized frequency range from 0.3554 to 0.4175.This study is expected to provide theoretical references for the study of slow-light buffering devices based on PhCs with high NDBP values.展开更多
In order to suppress the influence of temperature changes on the performance of accelerometers,a digital quartz resonant accelerometer with low temperature drift is developed using a quartz resonator cluster as a tran...In order to suppress the influence of temperature changes on the performance of accelerometers,a digital quartz resonant accelerometer with low temperature drift is developed using a quartz resonator cluster as a transducer element.In addition,a digital intellectual property(IP) is designed in FPGA to achieve signal processing and fusion of integrated resonators.A testing system for digital quartz resonant accelerometers is established to characterize the performance under different conditions.The scale factor of the accelerometer prototype reaches 3561.63 Hz/g in the range of -1 g to +1 g,and 3542.5 Hz/g in the range of-10 g to+10 g.In different measurement ranges,the linear correlation coefficient R~2 of the accelerometer achieves greater than 0.998.The temperature drift of the accelerometer prototype is tested using a constant temperature test chamber,with a temperature change from -20℃ to 80℃.After temperature-drift compensation,the zero bias temperature coefficient falls to 0.08 mg/℃,and the scale factor temperature coefficient is 65.43 ppm/℃.The experimental results show that the digital quartz resonant accelerometer exhibits excellent sensitivity and low temperature drift.展开更多
Metamaterials with multistability have attracted much attention due to their extraordinary physical properties. In this paper, we report a novel multistable strategy that is reversible under external forces, based on ...Metamaterials with multistability have attracted much attention due to their extraordinary physical properties. In this paper, we report a novel multistable strategy that is reversible under external forces, based on the fact that a variational reversible locally resonant elastic metamaterial(LREM) with four configurations is proposed. Through a combination of theoretical analysis and numerical simulations, this newly designed metamaterial is proven to exhibit different bandgap ranges and vibration attenuation properties in each configuration. Especially, there is tunable anisotropy shown in these configurations, which enables the bandgaps in two directions to be separated or overlapped. A model with a bandgap shifting ratio(BSR) of 100% and an overlap ratio of 25% is set to validate the multistable strategy feasibility. The proposed design strategy demonstrates significant potentials for applications in versatile scenarios.展开更多
This paper presents a locally resonant phononic crystal with excellent noise reduction in the low-frequency range as a soundproofing plate in mufflers.A locally resonant phononic crystal is established,and the bandgap...This paper presents a locally resonant phononic crystal with excellent noise reduction in the low-frequency range as a soundproofing plate in mufflers.A locally resonant phononic crystal is established,and the bandgap range of the phononic crystal is analyzed by using COMSOL software.Taking the partition plate in the muffler as the object,the acoustic-solid coupling is studied to analyze the sound insulation characteristics of the locally resonant phononic crystal.A phononic crystal plate-like structure is established to analyze its noise reduction performance in the muffler.The results indicate that the locally resonant phononic crystal exhibits favorable low-frequency sound insulation performance within a bandgap range below 200 Hz.At 160 Hz,the noise reduction is 15 dB higher than that of ordinary partition plates.As the number of layers of the phononic crystal plate increases,its noise reduction effect gradually enhances,while the magnitude of the noise reduction increment tends to diminish.At 160 Hz,the single-,double-and triple-layer plates achieve peak reductions of 47,53 and 57 dB,respectively.Compared with the double-layer phononic crystal plate,the composite of the locally resonant phononic crystal plate and the steel plate has an average noise reduction of 5 dB higher.Through research and analysis of the composite locally resonant phononic crystal plates,more feasible combined structures can be provided for future muffler structural design.展开更多
The rapid-cycling synchrotron(RCS)is a crucial device for proton beam acceleration at the China Spallation Neutron Source,operating at a repetition frequency of 25 Hz.The beam power was increased from 100 kW to 140 kW...The rapid-cycling synchrotron(RCS)is a crucial device for proton beam acceleration at the China Spallation Neutron Source,operating at a repetition frequency of 25 Hz.The beam power was increased from 100 kW to 140 kW.This increase makes the on-orbit beam more sensitive to disturbances in various parts of the accelerator,including the RCS magnet power supply system.This paper presents a method for reducing the high-order harmonic current error in resonant power supplies for dipole magnets and examines its impact on the horizontal orbit offset of the beam.It adopts a control scheme that combines high-order harmonic current compensation with PI double-loop control of the resonant power supply.By utilizing the existing digital controller hardware in the RCS power supply system,this study demonstrates how to achieve precise control of the 50 Hz harmonic current output in a cost-effective manner.Ultimately,it enhances performance by reducing the current error by up to 50%and provides methodological support for future upgrades to the power supply system.Such improvements enhance the stability of the RCS,reducing the beam horizontal orbit deviation by at least 19.8%.展开更多
The quantum collision model provides a promising tool for investigating system-bath dynamics.Most studies of quantum collision models,however,are in the resonant regime.In quantum dynamics,the off-resonant interaction...The quantum collision model provides a promising tool for investigating system-bath dynamics.Most studies of quantum collision models,however,are in the resonant regime.In quantum dynamics,the off-resonant interactions often result in exciting effects.Therefore,it is important to investigate the quantum collision models in the off-resonant regime.A bath with a negative absolute temperature is expected to be instrumental in the development of thermal devices.The design of an effective bath with negative absolute temperature coupled to a qubit is a significant component for developing such thermal devices.In this study,we establish an effective negative-absolute-temperature bath coupled to a qubit with a quantum collision model in the far-off-resonant regime.We conduct a detailed systematic investigation of the off-resonant collision model and determine the presence of an additional constraint on the collision duration resulting from the far-off resonant collision.The dynamics of the collision model in the far-off-resonant regime are different from those beyond the far-off-resonant regime.Numerical simulations are used to confirm the validity of the proposed approach.展开更多
Due to their biological interpretability,memristors are widely used to simulate synapses between artificial neural networks.As a type of neural network whose dynamic behavior can be explained,the coupling of resonant ...Due to their biological interpretability,memristors are widely used to simulate synapses between artificial neural networks.As a type of neural network whose dynamic behavior can be explained,the coupling of resonant tunneling diode-based cellular neural networks(RTD-CNNs)with memristors has rarely been reported in the literature.Therefore,this paper designs a coupled RTD-CNN model with memristors(RTD-MCNN),investigating and analyzing the dynamic behavior of the RTD-MCNN.Based on this model,a simple encryption scheme for the protection of digital images in police forensic applications is proposed.The results show that the RTD-MCNN can have two positive Lyapunov exponents,and its output is influenced by the initial values,exhibiting multistability.Furthermore,a set of amplitudes in its output sequence is affected by the internal parameters of the memristor,leading to nonlinear variations.Undoubtedly,the rich dynamic behaviors described above make the RTD-MCNN highly suitable for the design of chaos-based encryption schemes in the field of privacy protection.Encryption tests and security analyses validate the effectiveness of this scheme.展开更多
Synchrotron method of resonant X-ray reflectivity 2D mapping has been applied to study ultrathin epitaxial layers of WS_(2)grown by pulsed laser deposition on Al_(2)O_(3)(0001)substrates.The measurements were carried ...Synchrotron method of resonant X-ray reflectivity 2D mapping has been applied to study ultrathin epitaxial layers of WS_(2)grown by pulsed laser deposition on Al_(2)O_(3)(0001)substrates.The measurements were carried out across the L absorption edge of tungsten to perform depth-dependent element-selective analysis sensitive to potential chemical modification of the WS_(2)layer in ambient conditions.Despite the few monolayer thickness of the studied film,the experimentally measured maps of reflectance as a function of incident angle and photon energy turned out to be quite informative showing well-pronounced interference effects near W absorption edge at 10210 eV.The synchrotron studies were complemented with conventional non-resonant reflectance measurements carried out in the laboratory at a fixed photon energy corresponding to Cu Kαemission.The reconstruction of the depth and energy dependent scattering length density within the studied multilayers was carried out using the OpenCL empowered fitting software utilizing spectral shaping algorithm which does not rely on the pre-measured reference absorption spectra.A thin WO_(x) layer has been revealed at the surface of the WS_(2)layer pointing out to the effect of water assisted photo-oxidation reported in a number of works related to ultrathin layers of transition metal dichalcogenides.展开更多
The Bessel-like vector vortex beam(BlVVB)has gained increasing significance across numerous applications.However,its practical application is restricted by manufacturing difficulties and polarization manipulation.Thus...The Bessel-like vector vortex beam(BlVVB)has gained increasing significance across numerous applications.However,its practical application is restricted by manufacturing difficulties and polarization manipulation.Thus,the ability to manipulate its degrees of freedom is highly desirable.In this paper,the full-domain polarization modulation of BlVVB within a hot atomic ensemble has been investigated.We begin with the theoretical analysis of the resonant magneto-optical effect of atoms with a horizontal linear-polarized beam and experimentally demonstrate precise manipulation of the polarization state across the entire domain of the BlVVB,achieving an error margin of less than 3°at various cross-sectional points.Our study provides a novel approach for the modulation of BlVVB based on atomic media,which holds potential applications in sensitive vector magnetometers,optical communications,and signal processing.展开更多
This study focuses on coupled vibrations of rotating thin-walled composite beams subjected to hygrothermal effects.In the existing literature,many studies have been conducted on coupled bending-torsional vibration and...This study focuses on coupled vibrations of rotating thin-walled composite beams subjected to hygrothermal effects.In the existing literature,many studies have been conducted on coupled bending-torsional vibration and resonance in hygrothermal environments.Few studies considered the coupled flapwise-edgewise and resonances of composite thin-walled beams.Considering this,the flapwise-edgewise coupling effects and resonant characteristics of rotating thin-walled composite beams in a hygrothermal environment are studied.The Rayleigh–Ritz method is used to solve the equations of the beam.Results indicate that flapwise-edgewise coupling factors are essential for the vibration analysis of rectangular thin-walled beams.The ply angle and setting angle strongly affect the internal and external resonances.Large ply angles can significantly reduce the chances of primary internal and external resonances occurring when the permitted rotational speed is lower.展开更多
In recent decades,the application of seismic metamaterials to protect civil infrastructures being free of the damage of earthquakes has been attracting extensive attention.Specifically,the proposed locally resonant se...In recent decades,the application of seismic metamaterials to protect civil infrastructures being free of the damage of earthquakes has been attracting extensive attention.Specifically,the proposed locally resonant seismic metamaterials provide the probability of isolating the low-frequency seismic wave using a small-size isolation barrier.However,in previous studies,the energy absorption properties of locally resonant seismic metamaterials remain one of the least understood aspects of isolation.Benefit from the fascinating energy absorption characteristic of negative Poisson ratio(NPR)metamaterial,we creatively design a new seismic metamaterial structure by assembling the locally resonant seismic metamaterial and NPR metamaterial,to isolate seismic waves.The sound cone technique combining the transmission spectrum is employed to identify the surface wave from the hybrid waves.The generation mechanism of frequency bandgap and the isolation effectiveness of the proposed seismic metamaterial are discussed in detail.The results indicate that the generation of ultra-low and ultra-wide frequency bandgap with the range of 0.65 Hz–18.9 Hz is attributed to the locally resonant and energy absorption of the proposed seismic metamaterial structure and the excellent isolation effect is achieved by transforming the surface wave into the bulk wave.The frequency bandgap narrows as the distance increases between each resonator.In addition,the mechanical properties of the NPR bearing,such as the Poisson ratio,mass density,and elastic modulus,have remarkable impact on the frequency bandgap,especially on the upper bound frequency.In practical engineering,the NPR bearing with a low Poisson ratio,small mass density,and high elastic modulus is suggested for the design of the NPR locally resonant seismic metamaterial structures.Time domain analysis for the practical seismic wave verifies that the proposed seismic metamaterial has a promising application in isolating ultra-low and ultra-wide seismic waves,with the isolation effectiveness larger than 70%.This work contributes a new locally resonance seismic metamaterial design idea for isolating and adjusting the low-frequency seismic wave.展开更多
The effects of equilibrium toroidal rotation during edge-localized mode(ELM)mitigated by resonant magnetic perturbation(RMP)are studied with the experimental equilibria of the EAST tokamak based on the four-field mode...The effects of equilibrium toroidal rotation during edge-localized mode(ELM)mitigated by resonant magnetic perturbation(RMP)are studied with the experimental equilibria of the EAST tokamak based on the four-field model in the BOUT++code.As the two main parameters to determine the toroidal rotation profiles,the rotation shear and magnitudes were separately scanned to investigate their roles in the impact of RMPs on peeling-ballooning(P-B)modes.On one hand,the results show that strong toroidal rotation shear is favorable for the enhancement of the self-generated E×B shearing rate<ω_(E×B)>with RMPs,leading to significant ELM mitigation with RMP in the stronger toroidal rotation shear region.On the other hand,toroidal rotation magnitudes may affect ELM mitigation by changing the penetration of the RMPs,more precisely the resonant components.RMPs can lead to a reduction in the pedestal energy loss by enhancing the multimode coupling in the turbulence transport phase.The shielding effects on RMPs increase with the toroidal rotation magnitude,leading to the enhancement of the multimode coupling with RMPs to be significantly weakened.Hence,the reduction in pedestal energy loss by RMPs decreased with the rotation magnitude.In brief,the results show that toroidal rotation plays a dual role in ELM mitigation with RMP by changing the shielding effects of plasma by rotation magnitude and affecting<ω_(E×B)>by rotation shear.In the high toroidal rotation region,toroidal rotation shear is usually strong and hence plays a dominant role in the influence of RMP on P-B modes,whereas in the low rotation region,toroidal rotation shear is weak and has negligible impact on P-B modes,and the rotation magnitude plays a dominant role in the influence of RMPs on the P-B modes by changing the field penetration.Therefore,the dual role of toroidal rotation leads to stronger ELM mitigation with RMP,which may be achieved both in the low toroidal rotation region and the relatively high rotation region that has strong rotational shear.展开更多
The seismic behavior of a partially filled rigid rectangular liquid tank is investigated under short-and longduration ground motions.A finite element model is developed to analyze the liquid domain by using four-noded...The seismic behavior of a partially filled rigid rectangular liquid tank is investigated under short-and longduration ground motions.A finite element model is developed to analyze the liquid domain by using four-noded quadrilateral elements.The competency of the model is verified with the available results.Parametric studies are conducted for the dynamic parameters of the base-isolated tank,using a lead rubber bearing to evaluate the optimum damping and time period of the isolator.The application of base isolation has reduced the total and impulsive hydrodynamic components of pressure by 80 to 90 percent,and base shear by 15 to 95 percent,depending upon the frequency content and duration of the considered earthquakes.The sloshing amplitude of the base-isolated tank is reduced by 18 to 94 percent for most of the short-duration earthquakes,while it is increased by 17 to 60 percent for the majority of the long-duration earthquakes.Furthermore,resonance studies are carried out through a long-duration harmonic excitation to obtain the dynamic behavior of non-isolated and isolated tanks,using a nonlinear sloshing model.The seismic responses of the base-isolated tank are obtained as higher when the excitation frequency matches the fundamental sloshing frequency rather than the isolator frequency.展开更多
Research of infinite-layer nickelates has unveiled a broken translation symmetry,which has sparked significant interest in its root,its relationship to superconductivity,and its comparison to charge order in cuprates....Research of infinite-layer nickelates has unveiled a broken translation symmetry,which has sparked significant interest in its root,its relationship to superconductivity,and its comparison to charge order in cuprates.In this study,resonant x-ray scattering measurements were performed on thin films of infinite-layer PrNiO_(2+δ).The results show significant differences in the superlattice reflection at the Ni L_(3) absorption edge compared to that at the Pr M_(5) resonance in their dependence on energy,temperature,and local symmetry.These differences point to two distinct charge orders,although they share the same in-plane wavevectors.It is suggested that these dissimilarities could be linked to the excess oxygen dopants,given that the resonant reflections were observed in an incompletely reduced PrNiO_(2+δ)film.Furthermore,azimuthal analysis indicates that the oxygen ligands likely play a crucial role in the charge modulation revealed at the Ni L_(3) resonance.展开更多
For systems modeled by the resonant nonlinear Schrödinger equation(RNLSE)with generalized cubic-quintic nonlinearity,we derive the bright soliton solution of the equation in(1+1)dimensions,using the modified F-ex...For systems modeled by the resonant nonlinear Schrödinger equation(RNLSE)with generalized cubic-quintic nonlinearity,we derive the bright soliton solution of the equation in(1+1)dimensions,using the modified F-expansion method along with the novel ansatz of F-base function.Furthermore,we extend the analytical study of soliton dynamics to higher(2+1)and(3+1)dimensions by using the self-similar method,and demonstrate the soliton behavior via graphical illustration.Moreover,we investigate the effect of the resonance term on bright soliton solution in(1+1)dimensions.Additionally,we consider the nonlinear equation models with perturbation terms and derive the bright soliton solutions for the one-dimensional(1D)to three-dimensional(3D)cases.The theoretical results derived can be used to guide the experimental studies and observations of bright solitons in systems described by RNLSE model.展开更多
Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modula...Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modulation experiment, the particle transport coefficients were calculated using the experimental data, and the result shows that the particle transport coefficients increase with RMP. In this study, the six-field two-fluid model in BOUT++ is used to simulate the transport before and after density pump-out induced by RMP,respectively referred as the case without RMP and the case with RMP. In the linear simulations,the instabilities generally decreases for cases with RMP. In the nonlinear simulation, ELM only appears in the case without RMP. Additionally, the particle transport coefficient was analyzed,and the result shows that the particle transport coefficient becomes larger for the case with RMP,which is consistent with the experimental conclusion. Moreover, its magnitude is comparable to the results calculated from experimental data.展开更多
Silicon resonant pressure sensors are widely used in aerospace and industry due to their high accuracy,good linearity,and long-term stability.Due to the stress and signal processing limitation,its accuracy is difficul...Silicon resonant pressure sensors are widely used in aerospace and industry due to their high accuracy,good linearity,and long-term stability.Due to the stress and signal processing limitation,its accuracy is difficult to meet the application requirements,and we can only search methods to approach this continuously.This research introduces a stress-isolated structure and a processing method of frequency signal to enhance the index.The stress-isolated structure separates the press-sensor from the printed circuit board by nested bonding for plates with silica gel.It minimizes the transmitted stress but no affect on the electrical connection.The analysis algorithm of frequency based on a given waveform number instead of a given time improves the analytical accuracy of frequency and pressure.By redesigning the interrupt timing control strategy in Microcontroller unit,it addresses sudden jumps of frequency signal.The proposed technique compared to similar schemes,tested on a resonant pressure sensor at a temperature condition of-45℃to 75℃and barometric condition of 3.5 kPa to 110 kPa,reduces the effect of stress effectively,and enhances to 0.01Hz in accuracy of frequency.More importantly there is no sudden jump in frequency signal.The pressure accuracy is increased by 3.5 times to 0.0145%after calibrating.Over-all,the advised method meets the requirement of high accuracy and promotes applications in the aerospace field.展开更多
This paper proposes a numerical method to analyze the ice protection capability and predict the power requirements of a piezoelectric resonant de-icing system.The method is based on a coupled electro-mechanical finite...This paper proposes a numerical method to analyze the ice protection capability and predict the power requirements of a piezoelectric resonant de-icing system.The method is based on a coupled electro-mechanical finite element analysis which enables the fast computation of the modes of resonance of interest to de-ice curved surfaces and the estimation of the input voltage and current required for a given configuration(defined by its mode,actuator location,ice deposit,etc.).Eventually,the electric power to be supplied can be also assessed.The method is applied to a NACA 0024 leading edge equipped with piezoelectric actuators.First,two extension modes are analyzed and compared with respect to their efficiency and power requirements.Then,tests are carried out in an icing tunnel to verify the effectiveness of the piezoelectric ice protection system and the predictions of the maximal required power.The system allows de-icing the leading edge in less than 2 s for a glaze ice deposit.展开更多
The shell composed of large-scale parts is the essential component of mechanical structures in the aerospace,shipping,and railway industries.These workpieces are characterized by thin walls and weak rigidity,thus requ...The shell composed of large-scale parts is the essential component of mechanical structures in the aerospace,shipping,and railway industries.These workpieces are characterized by thin walls and weak rigidity,thus requiring an effective technology for high-performance machining.Accordingly,an embedded locally resonant metamaterial with double resonators is proposed and combined with the magnetic follow-up support technology to attenuate the vibration of thin-walled parts for the first time.The band structures and parametric adjustment laws are systematically investigated and validated by analytical calculation and finite element method,which proves the proposed model is broadband,lightweight,and flexible in low frequencies.Its characteristics,as well as the relatively simple structure,are unique advantages for thin-walled structure milling.Finally,mirror milling experiments have been performed to assess the slave module with the proposed substructure.From the results,the root mean square amplitude of the thin-walled workpiece with the combined device decreases by nearly 9%,which means that the performance has been improved by the combined device.Furthermore,this work provides an integrated and efficient solution for vibration suppression in thin-walled parts milling,which extends locally resonant metamaterials to practical engineering fields and helps to improve the status quo of mirror milling from the perspective of metamaterials.展开更多
Resonant accelerometer is designed,which includes two double-ended tuning forks,a proof mass,four-leverage system amplifying inertial force,and drive/sense combs.Each tuning fork is electrostatically actuated and sens...Resonant accelerometer is designed,which includes two double-ended tuning forks,a proof mass,four-leverage system amplifying inertial force,and drive/sense combs.Each tuning fork is electrostatically actuated and sensed at resonance using comb electrodes.The device is fabricated using MEMS bulk-silicon technology,whose sensitive degree is 27 3Hz/g,and the resolution is 167 8μg.展开更多
基金supported by the Graduate Student Innovation Fund of Xi’an Shiyou University(No.YCS21211087).
文摘This paper presents a photonic crystal(PhC)line-defect slow-light waveguide modified by resonant rings.We introduce resonant rings into the line defect,constructing a slow-light waveguide with high normalized delay bandwidth product(NDBP)and low group velocity dispersion(GVD).We simulate,analyze,and optimize the structural parameters of this slow-light waveguide using the finite difference time domain(FDTD)method,theoretically achieving a maximum group index of 3.7,maximum bandwidth of 15.6 nm,and maximum NDBP of 0.4416 for slow-light effect.The resonant ring-modified PhC slow-light waveguide designed in this paper exhibits GVD lower than the order of 10^(−20)s^(2)/m over a normalized frequency range from 0.3554 to 0.4175.This study is expected to provide theoretical references for the study of slow-light buffering devices based on PhCs with high NDBP values.
文摘In order to suppress the influence of temperature changes on the performance of accelerometers,a digital quartz resonant accelerometer with low temperature drift is developed using a quartz resonator cluster as a transducer element.In addition,a digital intellectual property(IP) is designed in FPGA to achieve signal processing and fusion of integrated resonators.A testing system for digital quartz resonant accelerometers is established to characterize the performance under different conditions.The scale factor of the accelerometer prototype reaches 3561.63 Hz/g in the range of -1 g to +1 g,and 3542.5 Hz/g in the range of-10 g to+10 g.In different measurement ranges,the linear correlation coefficient R~2 of the accelerometer achieves greater than 0.998.The temperature drift of the accelerometer prototype is tested using a constant temperature test chamber,with a temperature change from -20℃ to 80℃.After temperature-drift compensation,the zero bias temperature coefficient falls to 0.08 mg/℃,and the scale factor temperature coefficient is 65.43 ppm/℃.The experimental results show that the digital quartz resonant accelerometer exhibits excellent sensitivity and low temperature drift.
基金supported by the National Natural Science Foundation of China(No.52192633)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2025JC-YBMS-050)。
文摘Metamaterials with multistability have attracted much attention due to their extraordinary physical properties. In this paper, we report a novel multistable strategy that is reversible under external forces, based on the fact that a variational reversible locally resonant elastic metamaterial(LREM) with four configurations is proposed. Through a combination of theoretical analysis and numerical simulations, this newly designed metamaterial is proven to exhibit different bandgap ranges and vibration attenuation properties in each configuration. Especially, there is tunable anisotropy shown in these configurations, which enables the bandgaps in two directions to be separated or overlapped. A model with a bandgap shifting ratio(BSR) of 100% and an overlap ratio of 25% is set to validate the multistable strategy feasibility. The proposed design strategy demonstrates significant potentials for applications in versatile scenarios.
基金National Natural Science Foundation of China(No.51705545)。
文摘This paper presents a locally resonant phononic crystal with excellent noise reduction in the low-frequency range as a soundproofing plate in mufflers.A locally resonant phononic crystal is established,and the bandgap range of the phononic crystal is analyzed by using COMSOL software.Taking the partition plate in the muffler as the object,the acoustic-solid coupling is studied to analyze the sound insulation characteristics of the locally resonant phononic crystal.A phononic crystal plate-like structure is established to analyze its noise reduction performance in the muffler.The results indicate that the locally resonant phononic crystal exhibits favorable low-frequency sound insulation performance within a bandgap range below 200 Hz.At 160 Hz,the noise reduction is 15 dB higher than that of ordinary partition plates.As the number of layers of the phononic crystal plate increases,its noise reduction effect gradually enhances,while the magnitude of the noise reduction increment tends to diminish.At 160 Hz,the single-,double-and triple-layer plates achieve peak reductions of 47,53 and 57 dB,respectively.Compared with the double-layer phononic crystal plate,the composite of the locally resonant phononic crystal plate and the steel plate has an average noise reduction of 5 dB higher.Through research and analysis of the composite locally resonant phononic crystal plates,more feasible combined structures can be provided for future muffler structural design.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(No.2023B1515120030).
文摘The rapid-cycling synchrotron(RCS)is a crucial device for proton beam acceleration at the China Spallation Neutron Source,operating at a repetition frequency of 25 Hz.The beam power was increased from 100 kW to 140 kW.This increase makes the on-orbit beam more sensitive to disturbances in various parts of the accelerator,including the RCS magnet power supply system.This paper presents a method for reducing the high-order harmonic current error in resonant power supplies for dipole magnets and examines its impact on the horizontal orbit offset of the beam.It adopts a control scheme that combines high-order harmonic current compensation with PI double-loop control of the resonant power supply.By utilizing the existing digital controller hardware in the RCS power supply system,this study demonstrates how to achieve precise control of the 50 Hz harmonic current output in a cost-effective manner.Ultimately,it enhances performance by reducing the current error by up to 50%and provides methodological support for future upgrades to the power supply system.Such improvements enhance the stability of the RCS,reducing the beam horizontal orbit deviation by at least 19.8%.
基金supported by the Taishan Scholar Project of Shandong Province(Grant No.tsqn201812059)the National Natural Science Foundation of China(Grant Nos.11505023,11974209,and 12274257)。
文摘The quantum collision model provides a promising tool for investigating system-bath dynamics.Most studies of quantum collision models,however,are in the resonant regime.In quantum dynamics,the off-resonant interactions often result in exciting effects.Therefore,it is important to investigate the quantum collision models in the off-resonant regime.A bath with a negative absolute temperature is expected to be instrumental in the development of thermal devices.The design of an effective bath with negative absolute temperature coupled to a qubit is a significant component for developing such thermal devices.In this study,we establish an effective negative-absolute-temperature bath coupled to a qubit with a quantum collision model in the far-off-resonant regime.We conduct a detailed systematic investigation of the off-resonant collision model and determine the presence of an additional constraint on the collision duration resulting from the far-off resonant collision.The dynamics of the collision model in the far-off-resonant regime are different from those beyond the far-off-resonant regime.Numerical simulations are used to confirm the validity of the proposed approach.
基金supported by the Scientific Research Fund of Hunan Provincial Education Department(Grant No.24A0248)the National Key Research and Development Program“National Quality Infrastructure System”Special Project(Grant No.2024YFF0617900)the Hefei Minglong Electronic Technology Co.,Ltd.(Grant Nos.2024ZKHX293,2024ZKHX294,and 2024ZKHX295).
文摘Due to their biological interpretability,memristors are widely used to simulate synapses between artificial neural networks.As a type of neural network whose dynamic behavior can be explained,the coupling of resonant tunneling diode-based cellular neural networks(RTD-CNNs)with memristors has rarely been reported in the literature.Therefore,this paper designs a coupled RTD-CNN model with memristors(RTD-MCNN),investigating and analyzing the dynamic behavior of the RTD-MCNN.Based on this model,a simple encryption scheme for the protection of digital images in police forensic applications is proposed.The results show that the RTD-MCNN can have two positive Lyapunov exponents,and its output is influenced by the initial values,exhibiting multistability.Furthermore,a set of amplitudes in its output sequence is affected by the internal parameters of the memristor,leading to nonlinear variations.Undoubtedly,the rich dynamic behaviors described above make the RTD-MCNN highly suitable for the design of chaos-based encryption schemes in the field of privacy protection.Encryption tests and security analyses validate the effectiveness of this scheme.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(agreement No.075-15-2021-1349)。
文摘Synchrotron method of resonant X-ray reflectivity 2D mapping has been applied to study ultrathin epitaxial layers of WS_(2)grown by pulsed laser deposition on Al_(2)O_(3)(0001)substrates.The measurements were carried out across the L absorption edge of tungsten to perform depth-dependent element-selective analysis sensitive to potential chemical modification of the WS_(2)layer in ambient conditions.Despite the few monolayer thickness of the studied film,the experimentally measured maps of reflectance as a function of incident angle and photon energy turned out to be quite informative showing well-pronounced interference effects near W absorption edge at 10210 eV.The synchrotron studies were complemented with conventional non-resonant reflectance measurements carried out in the laboratory at a fixed photon energy corresponding to Cu Kαemission.The reconstruction of the depth and energy dependent scattering length density within the studied multilayers was carried out using the OpenCL empowered fitting software utilizing spectral shaping algorithm which does not rely on the pre-measured reference absorption spectra.A thin WO_(x) layer has been revealed at the surface of the WS_(2)layer pointing out to the effect of water assisted photo-oxidation reported in a number of works related to ultrathin layers of transition metal dichalcogenides.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12033007,61801458,12103058,12203058,12074309,and 61875205)the Key Project of Frontier Science Research of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-SLH007)+2 种基金the Strategic Priority Research Program of CAS(Grant No.XDC07020200)the Youth Innovation Promotion Association,CAS(Grant Nos.2021408,2022413,and 2023425)the Research on Highly Sensitive Long-Wave Receiver Based on Rydberg Atoms(Grant No.1P2024000059)。
文摘The Bessel-like vector vortex beam(BlVVB)has gained increasing significance across numerous applications.However,its practical application is restricted by manufacturing difficulties and polarization manipulation.Thus,the ability to manipulate its degrees of freedom is highly desirable.In this paper,the full-domain polarization modulation of BlVVB within a hot atomic ensemble has been investigated.We begin with the theoretical analysis of the resonant magneto-optical effect of atoms with a horizontal linear-polarized beam and experimentally demonstrate precise manipulation of the polarization state across the entire domain of the BlVVB,achieving an error margin of less than 3°at various cross-sectional points.Our study provides a novel approach for the modulation of BlVVB based on atomic media,which holds potential applications in sensitive vector magnetometers,optical communications,and signal processing.
基金supported by the National Natural Science Foundation of China(Grant Nos.11902002 and 51705002)the Sichuan Provincial Natural Science Foundation(Grant No.2022NSFSC0275)the University Outstanding Youth Researcher Support Program of the Education Department of Anhui Province,and the Teaching Project of the Education Department of Anhui Province(Grant No.2022xxsfkc023).
文摘This study focuses on coupled vibrations of rotating thin-walled composite beams subjected to hygrothermal effects.In the existing literature,many studies have been conducted on coupled bending-torsional vibration and resonance in hygrothermal environments.Few studies considered the coupled flapwise-edgewise and resonances of composite thin-walled beams.Considering this,the flapwise-edgewise coupling effects and resonant characteristics of rotating thin-walled composite beams in a hygrothermal environment are studied.The Rayleigh–Ritz method is used to solve the equations of the beam.Results indicate that flapwise-edgewise coupling factors are essential for the vibration analysis of rectangular thin-walled beams.The ply angle and setting angle strongly affect the internal and external resonances.Large ply angles can significantly reduce the chances of primary internal and external resonances occurring when the permitted rotational speed is lower.
基金supported by the National Natural Science Foundation(Grant Nos.52208344 and 52278350)the Natural Science Foundation of Jiangxi Province(Grant Nos.20224BAB214068 and 20212BDH81034)+1 种基金Education Department of Jiangxi Province(Grant No.GJJ2200673)Open Project of State Key Laboratory(Grant No.HJGZ2022204).
文摘In recent decades,the application of seismic metamaterials to protect civil infrastructures being free of the damage of earthquakes has been attracting extensive attention.Specifically,the proposed locally resonant seismic metamaterials provide the probability of isolating the low-frequency seismic wave using a small-size isolation barrier.However,in previous studies,the energy absorption properties of locally resonant seismic metamaterials remain one of the least understood aspects of isolation.Benefit from the fascinating energy absorption characteristic of negative Poisson ratio(NPR)metamaterial,we creatively design a new seismic metamaterial structure by assembling the locally resonant seismic metamaterial and NPR metamaterial,to isolate seismic waves.The sound cone technique combining the transmission spectrum is employed to identify the surface wave from the hybrid waves.The generation mechanism of frequency bandgap and the isolation effectiveness of the proposed seismic metamaterial are discussed in detail.The results indicate that the generation of ultra-low and ultra-wide frequency bandgap with the range of 0.65 Hz–18.9 Hz is attributed to the locally resonant and energy absorption of the proposed seismic metamaterial structure and the excellent isolation effect is achieved by transforming the surface wave into the bulk wave.The frequency bandgap narrows as the distance increases between each resonator.In addition,the mechanical properties of the NPR bearing,such as the Poisson ratio,mass density,and elastic modulus,have remarkable impact on the frequency bandgap,especially on the upper bound frequency.In practical engineering,the NPR bearing with a low Poisson ratio,small mass density,and high elastic modulus is suggested for the design of the NPR locally resonant seismic metamaterial structures.Time domain analysis for the practical seismic wave verifies that the proposed seismic metamaterial has a promising application in isolating ultra-low and ultra-wide seismic waves,with the isolation effectiveness larger than 70%.This work contributes a new locally resonance seismic metamaterial design idea for isolating and adjusting the low-frequency seismic wave.
基金supported by the National MCF Energy R&D Program of China(Nos.2019YFE03090400 and 2019YFE03030004)National Natural Science Foundation of China(Nos.12375222 and 11775154)National Key R&D Program of China(Nos.2017YFE0301203 and 2017YFE0301101)。
文摘The effects of equilibrium toroidal rotation during edge-localized mode(ELM)mitigated by resonant magnetic perturbation(RMP)are studied with the experimental equilibria of the EAST tokamak based on the four-field model in the BOUT++code.As the two main parameters to determine the toroidal rotation profiles,the rotation shear and magnitudes were separately scanned to investigate their roles in the impact of RMPs on peeling-ballooning(P-B)modes.On one hand,the results show that strong toroidal rotation shear is favorable for the enhancement of the self-generated E×B shearing rate<ω_(E×B)>with RMPs,leading to significant ELM mitigation with RMP in the stronger toroidal rotation shear region.On the other hand,toroidal rotation magnitudes may affect ELM mitigation by changing the penetration of the RMPs,more precisely the resonant components.RMPs can lead to a reduction in the pedestal energy loss by enhancing the multimode coupling in the turbulence transport phase.The shielding effects on RMPs increase with the toroidal rotation magnitude,leading to the enhancement of the multimode coupling with RMPs to be significantly weakened.Hence,the reduction in pedestal energy loss by RMPs decreased with the rotation magnitude.In brief,the results show that toroidal rotation plays a dual role in ELM mitigation with RMP by changing the shielding effects of plasma by rotation magnitude and affecting<ω_(E×B)>by rotation shear.In the high toroidal rotation region,toroidal rotation shear is usually strong and hence plays a dominant role in the influence of RMP on P-B modes,whereas in the low rotation region,toroidal rotation shear is weak and has negligible impact on P-B modes,and the rotation magnitude plays a dominant role in the influence of RMPs on the P-B modes by changing the field penetration.Therefore,the dual role of toroidal rotation leads to stronger ELM mitigation with RMP,which may be achieved both in the low toroidal rotation region and the relatively high rotation region that has strong rotational shear.
文摘The seismic behavior of a partially filled rigid rectangular liquid tank is investigated under short-and longduration ground motions.A finite element model is developed to analyze the liquid domain by using four-noded quadrilateral elements.The competency of the model is verified with the available results.Parametric studies are conducted for the dynamic parameters of the base-isolated tank,using a lead rubber bearing to evaluate the optimum damping and time period of the isolator.The application of base isolation has reduced the total and impulsive hydrodynamic components of pressure by 80 to 90 percent,and base shear by 15 to 95 percent,depending upon the frequency content and duration of the considered earthquakes.The sloshing amplitude of the base-isolated tank is reduced by 18 to 94 percent for most of the short-duration earthquakes,while it is increased by 17 to 60 percent for the majority of the long-duration earthquakes.Furthermore,resonance studies are carried out through a long-duration harmonic excitation to obtain the dynamic behavior of non-isolated and isolated tanks,using a nonlinear sloshing model.The seismic responses of the base-isolated tank are obtained as higher when the excitation frequency matches the fundamental sloshing frequency rather than the isolator frequency.
基金supported by the National Natural Science Foundation of China(Grant No.12074411)the National Key Research and Development Program of China(Grant Nos.2022YFA1403900 and 2021YFA1401800)+1 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB25000000)the Swiss National Science Foundation(Grant No.200021_188564)。
文摘Research of infinite-layer nickelates has unveiled a broken translation symmetry,which has sparked significant interest in its root,its relationship to superconductivity,and its comparison to charge order in cuprates.In this study,resonant x-ray scattering measurements were performed on thin films of infinite-layer PrNiO_(2+δ).The results show significant differences in the superlattice reflection at the Ni L_(3) absorption edge compared to that at the Pr M_(5) resonance in their dependence on energy,temperature,and local symmetry.These differences point to two distinct charge orders,although they share the same in-plane wavevectors.It is suggested that these dissimilarities could be linked to the excess oxygen dopants,given that the resonant reflections were observed in an incompletely reduced PrNiO_(2+δ)film.Furthermore,azimuthal analysis indicates that the oxygen ligands likely play a crucial role in the charge modulation revealed at the Ni L_(3) resonance.
基金Project supported by the National Natural Science Foundation of China(Grant No.11547024)。
文摘For systems modeled by the resonant nonlinear Schrödinger equation(RNLSE)with generalized cubic-quintic nonlinearity,we derive the bright soliton solution of the equation in(1+1)dimensions,using the modified F-expansion method along with the novel ansatz of F-base function.Furthermore,we extend the analytical study of soliton dynamics to higher(2+1)and(3+1)dimensions by using the self-similar method,and demonstrate the soliton behavior via graphical illustration.Moreover,we investigate the effect of the resonance term on bright soliton solution in(1+1)dimensions.Additionally,we consider the nonlinear equation models with perturbation terms and derive the bright soliton solutions for the one-dimensional(1D)to three-dimensional(3D)cases.The theoretical results derived can be used to guide the experimental studies and observations of bright solitons in systems described by RNLSE model.
基金supported by the National Magnetic Confinement Fusion Program of China(No.2019YFE03090200)by National Natural Science Foundation of China(Nos.11975231,12175277 and 12305249).
文摘Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modulation experiment, the particle transport coefficients were calculated using the experimental data, and the result shows that the particle transport coefficients increase with RMP. In this study, the six-field two-fluid model in BOUT++ is used to simulate the transport before and after density pump-out induced by RMP,respectively referred as the case without RMP and the case with RMP. In the linear simulations,the instabilities generally decreases for cases with RMP. In the nonlinear simulation, ELM only appears in the case without RMP. Additionally, the particle transport coefficient was analyzed,and the result shows that the particle transport coefficient becomes larger for the case with RMP,which is consistent with the experimental conclusion. Moreover, its magnitude is comparable to the results calculated from experimental data.
文摘Silicon resonant pressure sensors are widely used in aerospace and industry due to their high accuracy,good linearity,and long-term stability.Due to the stress and signal processing limitation,its accuracy is difficult to meet the application requirements,and we can only search methods to approach this continuously.This research introduces a stress-isolated structure and a processing method of frequency signal to enhance the index.The stress-isolated structure separates the press-sensor from the printed circuit board by nested bonding for plates with silica gel.It minimizes the transmitted stress but no affect on the electrical connection.The analysis algorithm of frequency based on a given waveform number instead of a given time improves the analytical accuracy of frequency and pressure.By redesigning the interrupt timing control strategy in Microcontroller unit,it addresses sudden jumps of frequency signal.The proposed technique compared to similar schemes,tested on a resonant pressure sensor at a temperature condition of-45℃to 75℃and barometric condition of 3.5 kPa to 110 kPa,reduces the effect of stress effectively,and enhances to 0.01Hz in accuracy of frequency.More importantly there is no sudden jump in frequency signal.The pressure accuracy is increased by 3.5 times to 0.0145%after calibrating.Over-all,the advised method meets the requirement of high accuracy and promotes applications in the aerospace field.
文摘This paper proposes a numerical method to analyze the ice protection capability and predict the power requirements of a piezoelectric resonant de-icing system.The method is based on a coupled electro-mechanical finite element analysis which enables the fast computation of the modes of resonance of interest to de-ice curved surfaces and the estimation of the input voltage and current required for a given configuration(defined by its mode,actuator location,ice deposit,etc.).Eventually,the electric power to be supplied can be also assessed.The method is applied to a NACA 0024 leading edge equipped with piezoelectric actuators.First,two extension modes are analyzed and compared with respect to their efficiency and power requirements.Then,tests are carried out in an icing tunnel to verify the effectiveness of the piezoelectric ice protection system and the predictions of the maximal required power.The system allows de-icing the leading edge in less than 2 s for a glaze ice deposit.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172248,12021002,12302022,12132010)Tianjin Research Program of Application Foundation and Advanced Technology(Grant No.22JCQNJC00780)the IoT Standards and Application Key Laboratory of the Ministry of Industry and Information Technology(Grant No.202306).
文摘The shell composed of large-scale parts is the essential component of mechanical structures in the aerospace,shipping,and railway industries.These workpieces are characterized by thin walls and weak rigidity,thus requiring an effective technology for high-performance machining.Accordingly,an embedded locally resonant metamaterial with double resonators is proposed and combined with the magnetic follow-up support technology to attenuate the vibration of thin-walled parts for the first time.The band structures and parametric adjustment laws are systematically investigated and validated by analytical calculation and finite element method,which proves the proposed model is broadband,lightweight,and flexible in low frequencies.Its characteristics,as well as the relatively simple structure,are unique advantages for thin-walled structure milling.Finally,mirror milling experiments have been performed to assess the slave module with the proposed substructure.From the results,the root mean square amplitude of the thin-walled workpiece with the combined device decreases by nearly 9%,which means that the performance has been improved by the combined device.Furthermore,this work provides an integrated and efficient solution for vibration suppression in thin-walled parts milling,which extends locally resonant metamaterials to practical engineering fields and helps to improve the status quo of mirror milling from the perspective of metamaterials.
文摘Resonant accelerometer is designed,which includes two double-ended tuning forks,a proof mass,four-leverage system amplifying inertial force,and drive/sense combs.Each tuning fork is electrostatically actuated and sensed at resonance using comb electrodes.The device is fabricated using MEMS bulk-silicon technology,whose sensitive degree is 27 3Hz/g,and the resolution is 167 8μg.
