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
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
In order to address the issues that the magnetic coupled resonant wireless power transfer （MCR-WPT） system is sensitive to the resonant frequency and that transmission power is difficult to control with the non-resi...In order to address the issues that the magnetic coupled resonant wireless power transfer （MCR-WPT） system is sensitive to the resonant frequency and that transmission power is difficult to control with the non-resistive load in the MCR-WPT, a single-side regulation scheme for frequency and transmission power online is proposed, which is based on the inherent constraint relationships the among system parameters in the primary side. Thus, the communication between the primary side and the secondary side is avoided. First, the transfer models of resistance-capacitance load and resistance- inductance load are established, respectively. Next, the relationship between the input voltage phasor and the input current phasor is used to recognize the load property and value. Then, the coaxial rotation of the stepper motor and the rotating vacuum variable capacitor is conducted to unify resonant frequency both in the primary side and the secondary side. Finally, the regulations of both frequency and amplitude of input voltage are made to guarantee transmission power under a new resonant frequency point the same as the one when the only pure resistance part of load is accessed under the former resonant frequency point. Both simulation and experimental results indicate that the proposed regulation scheme can track remnant frequency and maintain transmission power constant.展开更多
Knowledge of the dynamic modulus of bituminous mixtures is practical and theoretically meaningful in pavement design,construction,and monitoring.The tests in the laboratory for the determination of asphalt concrete(AC...Knowledge of the dynamic modulus of bituminous mixtures is practical and theoretically meaningful in pavement design,construction,and monitoring.The tests in the laboratory for the determination of asphalt concrete(AC)moduli include the resilient modulus through the indirect tensile test(EN 12697-26),the complex modulus through the four point bending beam(EN 12697-26),the asphalt mixture performance tester(AMPT)and the simple performance tester(SPT)(AASHTO T342).Unfortunately,the tests above are time-consuming and quite expensive.On the other hand,the standard ASTM E1876 for resonant tests applies only to very thin(stocky)cylindrical samples(with a thickness-to-radius ratio,t/r,lower than 0.5)while the typical AC samples produced in the laboratory do not satisfy the ASTM E1876 requirements.Consequently,the main objective of this study is to set up and implement a tentative method to extend the range of applicability of the standard ASTM E1876 to common AC samples.The methodology was to carry out resonant tests on slender samples and to cut each of them into stocky samples(these latter complying with ASTM E1876 requirements in terms of t/r),deriving the master curve per material.These master curves allowed for deriving the value of the dynamic modulus for the given selected sample under its particular test conditions during the resonant test(i.e.,temperature and frequency).Consequently,simplified formulae were provided for AC samples.Results were compared to Witczak's estimates.These formulae provide an approximate tool to carry out low-cost and high-speed inferences at the laboratory stage on common AC samples,whatever their thickness is.Additional studies are needed to investigate the reliability of the method further and reduce uncertainties.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
Micromachined comb-drive electrostatic resonators with folded-cantilever beams were designed and fabricated. A combination of Rayleigh＇s method and finite-element analysis was used to calculate the resonant frequency...Micromachined comb-drive electrostatic resonators with folded-cantilever beams were designed and fabricated. A combination of Rayleigh＇s method and finite-element analysis was used to calculate the resonant frequency drift as we adjusted the device geometry and material parameters. Three micromachined lateral resonant resonators with different beam widths were fabricated. Their resonant frequencies were experimentally measured to be 64.5,147.2, and 255.5kHz, respectively, which are in good agreement with the simulated resonant frequency. It is shown that an improved frequency performance could be obtained on the poly 3C-SiC based device structural material systems with high Young＇s modulus.展开更多
A high performance AlAs/In0.53 Ga0.47 As/InAs resonant tunneling diode （RTD） on InP substrate is fabricated by inductively coupled plasma etching. This RTD has a peak-to-valley current ratio （PVCR） of 7. 57 and a ...A high performance AlAs/In0.53 Ga0.47 As/InAs resonant tunneling diode （RTD） on InP substrate is fabricated by inductively coupled plasma etching. This RTD has a peak-to-valley current ratio （PVCR） of 7. 57 and a peak current density Jp = 39.08kA/cm^2 under forward bias at room temperature. Under reverse bias, the corresponding values are 7.93 and 34.56kA/cm^2 . A resistive cutoff frequency of 18.75GHz is obtained with the effect of a parasitic probe pad and wire. The slightly asymmetrical current-voltage characteristics with a nominally symmetrical structure are also discussed.展开更多
The transitions of E0 ,E0 ＋A0, and E＋ in dilute GaAs（1-x） Nx alloys with x = 0.10% ,0.22% ,0.36% ,and 0.62% are observed by micro-photoluminescence. Resonant Raman scattering results further confirm that they are ...The transitions of E0 ,E0 ＋A0, and E＋ in dilute GaAs（1-x） Nx alloys with x = 0.10% ,0.22% ,0.36% ,and 0.62% are observed by micro-photoluminescence. Resonant Raman scattering results further confirm that they are from the intrinsic emissions in the studied dilute GaAsN alloys rather than some localized exciton emissions in the GaAsN alloys. The results show that the nitrogen-induced E E＋ and E0 ＋ A0 transitions in GaAsN alloys intersect at a nitrogen content of about 0.16%. It is demonstrated that a small amount of isoelectronic doping combined with micro-photoluminescence allows direct observation of above band gap transitions that are not usually accessible in photoluminescence.展开更多
A stochastic averaging method of quasi integrable and resonant Hamiltonian systems under excitation of fractional Gaussian noise （fGn） with the Hurst index 1/2 〈 H 〈 1 is proposed. First, the definition and the ba...A stochastic averaging method of quasi integrable and resonant Hamiltonian systems under excitation of fractional Gaussian noise （fGn） with the Hurst index 1/2 〈 H 〈 1 is proposed. First, the definition and the basic property of fGn and related fractional Brownian motion （iBm） are briefly introduced. Then, the averaged fractional stochastic differential equations （SDEs） for the first integrals and combinations of angle variables of the associated Hamiltonian systems are derived. The stationary probability density and statistics of the original systems are then obtained approximately by simulating the averaged SDEs numerically. An example is worked out to illustrate the proposed stochastic averaging method. It is shown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of original system agree well.展开更多
A Schottky gate resonant tunneling transistor （SGRTT） is fabricated. Relying on simulation by ATLAS software,we find that the gate voltages can be used to control the current of SGRTT when the emitter terminal is gr...A Schottky gate resonant tunneling transistor （SGRTT） is fabricated. Relying on simulation by ATLAS software,we find that the gate voltages can be used to control the current of SGRTT when the emitter terminal is grounded and a positive bias voltage is applied to the collector terminal. When the collector terminal is grounded, the gate voltages can control the peak voltage. As revealed by measurement results, the reason is that the gate voltages and the electric field distribution on emitter and collector terminal change the distribution of the depletion region.展开更多
The soft switching operation principle and operation performance of rugged resonant pole (RRP) is given. The applications of RRP in soft switching DC DC converter and soft switching inverter are discussed in detail. R...The soft switching operation principle and operation performance of rugged resonant pole (RRP) is given. The applications of RRP in soft switching DC DC converter and soft switching inverter are discussed in detail. RRP can constitute buck boost soft switching DC DC converter and isolated soft switching DC DC converter with the automatic limitation performance of output power. Partial series resonant DC DC converter with RRP can realize the zero voltage/zero current switching of power devices. RR...展开更多
A novel resonant dc link soft switching static inverter topology is presented. The soft switching operation principle and pulse width modulation control feature of dc link is analyzed in detail. The discrete pulse c...A novel resonant dc link soft switching static inverter topology is presented. The soft switching operation principle and pulse width modulation control feature of dc link is analyzed in detail. The discrete pulse control strategy of inverter bridge is discussed. The operation characteristics of inverter are analyzed and verified by experiment.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.
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.
基金The National Natural Science Youth Foundation of China(No.51507032)the Natural Science Foundation of Jiangsu Province(No.BK20150617)the Fundamental Research Funds for the Central Universities
文摘In order to address the issues that the magnetic coupled resonant wireless power transfer （MCR-WPT） system is sensitive to the resonant frequency and that transmission power is difficult to control with the non-resistive load in the MCR-WPT, a single-side regulation scheme for frequency and transmission power online is proposed, which is based on the inherent constraint relationships the among system parameters in the primary side. Thus, the communication between the primary side and the secondary side is avoided. First, the transfer models of resistance-capacitance load and resistance- inductance load are established, respectively. Next, the relationship between the input voltage phasor and the input current phasor is used to recognize the load property and value. Then, the coaxial rotation of the stepper motor and the rotating vacuum variable capacitor is conducted to unify resonant frequency both in the primary side and the secondary side. Finally, the regulations of both frequency and amplitude of input voltage are made to guarantee transmission power under a new resonant frequency point the same as the one when the only pure resistance part of load is accessed under the former resonant frequency point. Both simulation and experimental results indicate that the proposed regulation scheme can track remnant frequency and maintain transmission power constant.
文摘Knowledge of the dynamic modulus of bituminous mixtures is practical and theoretically meaningful in pavement design,construction,and monitoring.The tests in the laboratory for the determination of asphalt concrete(AC)moduli include the resilient modulus through the indirect tensile test(EN 12697-26),the complex modulus through the four point bending beam(EN 12697-26),the asphalt mixture performance tester(AMPT)and the simple performance tester(SPT)(AASHTO T342).Unfortunately,the tests above are time-consuming and quite expensive.On the other hand,the standard ASTM E1876 for resonant tests applies only to very thin(stocky)cylindrical samples(with a thickness-to-radius ratio,t/r,lower than 0.5)while the typical AC samples produced in the laboratory do not satisfy the ASTM E1876 requirements.Consequently,the main objective of this study is to set up and implement a tentative method to extend the range of applicability of the standard ASTM E1876 to common AC samples.The methodology was to carry out resonant tests on slender samples and to cut each of them into stocky samples(these latter complying with ASTM E1876 requirements in terms of t/r),deriving the master curve per material.These master curves allowed for deriving the value of the dynamic modulus for the given selected sample under its particular test conditions during the resonant test(i.e.,temperature and frequency).Consequently,simplified formulae were provided for AC samples.Results were compared to Witczak's estimates.These formulae provide an approximate tool to carry out low-cost and high-speed inferences at the laboratory stage on common AC samples,whatever their thickness is.Additional studies are needed to investigate the reliability of the method further and reduce uncertainties.
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.
文摘Micromachined comb-drive electrostatic resonators with folded-cantilever beams were designed and fabricated. A combination of Rayleigh＇s method and finite-element analysis was used to calculate the resonant frequency drift as we adjusted the device geometry and material parameters. Three micromachined lateral resonant resonators with different beam widths were fabricated. Their resonant frequencies were experimentally measured to be 64.5,147.2, and 255.5kHz, respectively, which are in good agreement with the simulated resonant frequency. It is shown that an improved frequency performance could be obtained on the poly 3C-SiC based device structural material systems with high Young＇s modulus.
文摘A high performance AlAs/In0.53 Ga0.47 As/InAs resonant tunneling diode （RTD） on InP substrate is fabricated by inductively coupled plasma etching. This RTD has a peak-to-valley current ratio （PVCR） of 7. 57 and a peak current density Jp = 39.08kA/cm^2 under forward bias at room temperature. Under reverse bias, the corresponding values are 7.93 and 34.56kA/cm^2 . A resistive cutoff frequency of 18.75GHz is obtained with the effect of a parasitic probe pad and wire. The slightly asymmetrical current-voltage characteristics with a nominally symmetrical structure are also discussed.
文摘The transitions of E0 ,E0 ＋A0, and E＋ in dilute GaAs（1-x） Nx alloys with x = 0.10% ,0.22% ,0.36% ,and 0.62% are observed by micro-photoluminescence. Resonant Raman scattering results further confirm that they are from the intrinsic emissions in the studied dilute GaAsN alloys rather than some localized exciton emissions in the GaAsN alloys. The results show that the nitrogen-induced E E＋ and E0 ＋ A0 transitions in GaAsN alloys intersect at a nitrogen content of about 0.16%. It is demonstrated that a small amount of isoelectronic doping combined with micro-photoluminescence allows direct observation of above band gap transitions that are not usually accessible in photoluminescence.
基金supported by the National Natural Science Foundation of China under grants nos.:11272279,11321202 and 11432012
文摘A stochastic averaging method of quasi integrable and resonant Hamiltonian systems under excitation of fractional Gaussian noise （fGn） with the Hurst index 1/2 〈 H 〈 1 is proposed. First, the definition and the basic property of fGn and related fractional Brownian motion （iBm） are briefly introduced. Then, the averaged fractional stochastic differential equations （SDEs） for the first integrals and combinations of angle variables of the associated Hamiltonian systems are derived. The stationary probability density and statistics of the original systems are then obtained approximately by simulating the averaged SDEs numerically. An example is worked out to illustrate the proposed stochastic averaging method. It is shown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of original system agree well.
文摘A Schottky gate resonant tunneling transistor （SGRTT） is fabricated. Relying on simulation by ATLAS software,we find that the gate voltages can be used to control the current of SGRTT when the emitter terminal is grounded and a positive bias voltage is applied to the collector terminal. When the collector terminal is grounded, the gate voltages can control the peak voltage. As revealed by measurement results, the reason is that the gate voltages and the electric field distribution on emitter and collector terminal change the distribution of the depletion region.
文摘The soft switching operation principle and operation performance of rugged resonant pole (RRP) is given. The applications of RRP in soft switching DC DC converter and soft switching inverter are discussed in detail. RRP can constitute buck boost soft switching DC DC converter and isolated soft switching DC DC converter with the automatic limitation performance of output power. Partial series resonant DC DC converter with RRP can realize the zero voltage/zero current switching of power devices. RR...
文摘A novel resonant dc link soft switching static inverter topology is presented. The soft switching operation principle and pulse width modulation control feature of dc link is analyzed in detail. The discrete pulse control strategy of inverter bridge is discussed. The operation characteristics of inverter are analyzed and verified by experiment.
