Статті в журналах: "High frequency resonance method"

1

Mühlhaus, V., and Y. Kanh. "Contactless resistivity measurement with the high‐frequency series resonance method." Review of Scientific Instruments 62, no. 10 (October 1991): 2465–68. http://dx.doi.org/10.1063/1.1142265.

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2

Ding, Yong, Tiesheng Wang, Xinyu Zhang, Yuxi Zhang, and Yifei Miao. "PCCPS-PWM based vehicle-network high frequency resonance suppression method." Journal of Physics: Conference Series 1754, no. 1 (February 1, 2021): 012107. http://dx.doi.org/10.1088/1742-6596/1754/1/012107.

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3

HEIN, STEFAN, THORSTEN HOHAGE, WERNER KOCH, and JOACHIM SCHÖBERL. "Acoustic resonances in a high-lift configuration." Journal of Fluid Mechanics 582 (June 14, 2007): 179–202. http://dx.doi.org/10.1017/s0022112007005770.

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Low- and high-frequency acoustic resonances are computed numerically via a high-order finite-element code for a generic two-dimensional high-lift configuration with a leading-edge slat. Zero mean flow is assumed, approximating the low-Mach-number situation at aircraft landing and approach. To avoid unphysical reflections at the boundaries of the truncated computational domain, perfectly matched layer absorbing boundary conditions are implemented in the form of the complex scaling method of atomic and molecular physics. It is shown that two types of resonance exist: resonances of surface waves which scale with the total airfoil length and longitudinal cavity-type resonances which scale with the slat cove length. Minima exist in the temporal decay rate which can be associated with the slat cove resonances and depend on the slat cove geometry. All resonances are damped owing to radiation losses. However, if coherent noise sources exist, as observed in low-Reynolds-number experiments, these sources can be enhanced acoustically by the above resonances if the source frequency is close to a resonant frequency.

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4

Xiong, Wei, Liyang Ou, Xuezhou Chen, and Chaobo Li. "Electrical Characterization Method for Resonance Performance of Photo-Elastic Modulators." Optics 2, no. 4 (December 3, 2021): 276–83. http://dx.doi.org/10.3390/opt2040026.

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As a kind of resonant device, the modulation efficiency of the photo-elastic modulator (PEM) is determined by its inherent resonance characteristics, including the resonance frequency and quality factor (Q-factor). The existing methods used to characterize the resonance performance of the PEM are mainly based on the optical method to measure the vibration parameters, but these methods are more complex, have a high cost, and are not able to accurately measure the quality factor. Therefore, this paper proposes an electrical characterization method based on impedance measurement. In this method, an equivalent circuit model for the PEM is established. By measuring the impedance vs. frequency curve of the PEM and using the equivalent circuit model for fitting analysis, we can obtain the parameters of the equivalent circuit model. With these parameters, we can eventually calculate the natural resonance frequency and quality factor. The above method was applied to some commercial PEM products for experimental verification. The experimental results show that this method can accurately measure the natural resonance frequency and quality factor of the PEM, and the error is less than 0.03%.

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5

Cao, Wu, Kangli Liu, Haotian Kang, Shunyu Wang, Dongchen Fan, and Jianfeng Zhao. "Resonance Detection Strategy for Multi-Parallel Inverter-Based Grid-Connected Renewable Power System Using Cascaded SOGI-FLL." Sustainability 11, no. 18 (September 4, 2019): 4839. http://dx.doi.org/10.3390/su11184839.

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The increasing use of multi-parallel grid-connected inverters introduces both high-quality and high-capacity power, while it tends to cause a resonance instability problem. A resonance damper can virtualize a resistor at resonant frequency to suppress the instability effectively, but the resonant frequency should be detected primarily. However, the resonant current or voltage is severely distorted and oscillating, which will lead to the resonant frequency extraction being more difficult. To address it, this paper proposes a resonance detection strategy based on the cascaded second-order generalized integrators (SOGI) and the normalized frequency locked loop (FLL). The cascaded structure ensures the accuracy by completely filtering the fundamental component from the detected voltage or current, and the normalization accelerates the frequency detection. The proposed method can be used as a crucial unit of the resonance damping controller. Finally, the performance of the proposed method is verified by the MATLAB-based simulation and Hardware-in-the-Loop (HIL)-based emulation results.

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6

Kirievskiy, Vladimir V., and Evgeny V. Kirievskiy. "Measuring of plasma’s velocity in electrodynamic railgun using high-frequency method." MATEC Web of Conferences 226 (2018): 04004. http://dx.doi.org/10.1051/matecconf/201822604004.

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A method is proposed for measuring the velocity of a moving plasma in an electrodynamic railgun in the part of internal ballistics. The achieved result is to provide a measurement of instantaneous velocity and an increase of the safety level for operation of measuring devices. The method is based on the excitation of the rail system of railgun high frequency electric oscillations during in due motion of plasma and creates current resonance. Then is continuously measured cyclic resonance frequency, and the instantaneous velocity of the plasma is determined by a formula, that consist of the current time, the cyclic resonance frequency, equivalent inductance of the power supply of railgun, linear inductance and rail length, and as well used as a model of measurement measure capacitance of capacitor, connected in parallel to rail of railgun grounded from one side. Application of plasma velocity measuring method is suitable for the highly-accurate control of plasma acceleration and pushed it to the railgun bodies with controlled acceleration, requiring measurement during movement of the plasma instantaneous values of velocity.

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7

Shoyama, Tadayoshi, and Koji Fujimoto. "Measurement of High Frequency Viscoelastic Properties of Deformed Rubber." Key Engineering Materials 715 (September 2016): 139–46. http://dx.doi.org/10.4028/www.scientific.net/kem.715.139.

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Bearings of small turbo machines support high speed rotors rotating with the frequency over 1 [kHz]. Such bearings are often supported with O-rings made of soft materials like rubber to attenuate high frequency oscillations. Dynamic properties of rubber supporters have been measured experimentally for individual dimensions, but the universal prediction of dynamic properties for various frequencies is difficult not only because rubbers exhibit nonlinearity against its strain, but because O-ring supporters deform heterogeneously. For the precise prediction, it is necessary to investigate the viscoelasticity of rubber under various deformations and frequencies. Such properties can be measured by the standard shear vibration non-response method of ISO 6721-6 (JIS K 7244-6). However this is applicable only to low frequency range under 100 [Hz] because of the limitation of resonance frequency of the load cell. In this research, based on BERM (Base Excitation Resonant Mass) method, a new method was developed to measure the complex shear modulus at high frequencies up to 1 [kHz] of rubber sheets under homogeneous shear deformations. In the presented method, the force is calculated from the acceleration of the mass instead of the direct measurement by a load cell. Hence accurate measurement became possible even in the range beyond the resonance frequency of a load cell. The measured shear storage modulus G’ and shear loss modulus G” of deformed rubber were presented.

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8

Coccetti, F., W. Dressel, P. Russer, L. Pierantoni, M. Farina, and T. Rozzi. "Accurate modeling of high frequency microelectromechanical systems (MEMS) switches in time- and frequency-domainc." Advances in Radio Science 1 (May 5, 2003): 135–38. http://dx.doi.org/10.5194/ars-1-135-2003.

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Abstract. In this contribution we present an accurate investigation of three different techniques for the modeling of complex planar circuits. The em analysis is performed by means of different electromagnetic full-wave solvers in the timedomain and in the frequency-domain. The first one is the Transmission Line Matrix (TLM) method. In the second one the TLM method is combined with the Integral Equation (IE) method. The latter is based on the Generalized Transverse Resonance Diffraction (GTRD). In order to test the methods we model different structures and compare the calculated Sparameters to measured results, with good agreement.

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9

Li, Linlin, Sumeet S. Aphale, and Limin Zhu. "High-bandwidth nanopositioning via active control of system resonance." Frontiers of Mechanical Engineering 16, no. 2 (March 5, 2021): 331–39. http://dx.doi.org/10.1007/s11465-020-0619-x.

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AbstractTypically, the achievable positioning bandwidth for piezo-actuated nanopositioners is severely limited by the first, lightly-damped resonance. To overcome this issue, a variety of open- and closed-loop control techniques that commonly combine damping and tracking actions, have been reported in literature. However, in almost all these cases, the achievable closed-loop bandwidth is still limited by the original open-loop resonant frequency of the respective positioning axis. Shifting this resonance to a higher frequency would undoubtedly result in a wider bandwidth. However, such a shift typically entails a major mechanical redesign of the nanopositioner. The integral resonant control (IRC) has been reported earlier to demonstrate the significant performance enhancement, robustness to parameter uncertainty, guaranteed stability and design flexibility it affords. To further exploit the IRC scheme’s capabilities, this paper presents a method of actively shifting the resonant frequency of a nanopositioner’s axis, thereby delivering a wider closed-loop positioning bandwidth when controlled with the IRC scheme. The IRC damping control is augmented with a standard integral tracking controller to improve positioning accuracy. And both damping and tracking control parameters are analytically optimized to result in a Butterworth Filter mimicking pole-placement—maximally flat passband response. Experiments are conducted on a nanopositioner’s axis with an open-loop resonance at 508 Hz. It is shown that by employing the active resonance shifting, the closed-loop positioning bandwidth is increased from 73 to 576 Hz. Consequently, the root-mean-square tracking errors for a 100 Hz triangular trajectory are reduced by 93%.

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10

Endo, Akito, Jun Akedo, and Shinichi Takeuchi. "Fundamental Study on High-Frequency Ultrasound Probes Fabricated by Aerosol Deposition Method and Hydrothermal Method." Key Engineering Materials 388 (September 2008): 159–62. http://dx.doi.org/10.4028/www.scientific.net/kem.388.159.

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The ultrasound probes utilized in this study were fabricated using lead zirconium titanate (PZT), which was deposited using two different methods—the aerosol deposition (AD) method and the hydrothermal method. The fabricated ultrasound probes had the same structure wherein an electrode and an acoustic backing block were attached to each transducer. In this study, we have compared the acoustic characteristics of a high-frequency ultrasound probe fabricated by the AD method with those of a probe fabricated using the hydrothermal method; further, we have studied and hence determined the optimal process that can be used in the fabrication of high-frequency ultrasound probes with a resonance frequency of 40 MHz. As a result, when the pickup voltage was compared, the ultrasound probes fabricated by the AD method exhibited a value 9.5 times higher than that of the probes fabricated by the hydrothermal method. Moreover, the ultrasound probes fabricated by the AD method were found to transmit pulses at resonance frequencies of 28 MHz, 45–50 MHz, and 82–88 MHz.

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11

Marák, Károly, Sándor Bilicz, and József Pávó. "Experimental technique for high-frequency conductivity measurement." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, no. 5 (September 2, 2019): 1711–22. http://dx.doi.org/10.1108/compel-12-2018-0502.

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Purpose The purpose of this study is to introduce a novel method for the measurement of electromagnetic material parameters. Design/methodology/approach The main idea behind the approach is the fact that for slabs with elongated shapes, the intensity of the backscattered field and the electromagnetic resonance frequency corresponding to the length of the sample are dependent on the conductivity of the sample’s material. Findings It is shown that for a known scattered field and resonance frequency, it is possible to formulate an inverse problem as to the calculation of the conductivity of the sample’s material at the considered frequencies. To investigate the applicability of the method, demonstrative experiments are performed during which the micro-Doppler effect is used to increase the measurement accuracy. The idea is extended to the case of anisotropic samples, with slight modifications proposed to the experimental setup in the case of significant anisotropy in the investigated material. Practical implications The measurement method may prove useful for the investigation of the high-frequency conductive properties of certain materials of interest. Originality/value To the best of the authors’ knowledge, this is the first time the use of the micro-Doppler effect is proposed for the purpose of the measurement of material parameters.

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12

Huang Min-Shuang, Ma Peng, and Liu Xiao-Chen. "Multi-pulse laser ranging method for pre-detection with high frequency resonance." Acta Physica Sinica 67, no. 7 (2018): 074202. http://dx.doi.org/10.7498/aps.67.20172079.

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13

Wu, Wentao, Tiantian Liang, Zhirong Lin, Yongliang Wang, Guofeng Zhang, Liliang Ying, Wei Peng, et al. "Resonance analysis using a high frequency simulation method for dc-SQUID amplifiers." Physica C: Superconductivity and its Applications 591 (December 2021): 1353976. http://dx.doi.org/10.1016/j.physc.2021.1353976.

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14

Aşırım, Özüm Emre, and Mustafa Kuzuoğlu. "Numerical Study of Resonant Optical Parametric Amplification via Gain Factor Optimization in Dispersive Microresonators." Photonics 7, no. 1 (December 25, 2019): 5. http://dx.doi.org/10.3390/photonics7010005.

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The achievement of wideband high-gain optical parametric amplification has not been shown in micrometer-scale cavities. In this paper we have computationally investigated the optical parametric amplification process in a few micrometer-long dispersive microresonator. By performing a gain medium resonance frequency dependent analysis of optical parametric amplification, we have found that it is possible to achieve a wideband high-gain optical amplification in a dispersive microresonator. In order to account for the effects of dispersion (modeled by the polarization damping coefficient) and the resonance frequency of the gain medium on optical parametric amplification, we have solved the wave equation in parallel with the nonlinear equation of electron cloud motion, using the finite difference time domain method. Then we have determined the resonance frequency values that yield an enhanced or a resonant case of optical parametric amplification, via gain factor optimization. It was observed that if the microresonator is more dispersive (has a lower polarization damping coefficient), then there are more resonance frequencies that yield an optical gain resonance. At these gain resonances, a very wideband, high-gain optical amplification seems possible in the micron scale, which, to our knowledge, has not been previously reported in the context of nonlinear wave mixing theory.

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15

Liu, Cai Qin, Er Ling Cao, and Sheng Qiang Wu. "A New Fault Diagnosis Method of Adaptive Demodulated Resonance Technique Based on Wavelet Packet in Multi-Information Domains." Advanced Materials Research 562-564 (August 2012): 1598–601. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.1598.

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Fault information is incomplete while using a single information domain fault feature parameters to construct fault feature vector, and demodulated resonance technique have to predetermine resonant frequency and fixed center frequency also has its shortcomings , in order to solve these problems, a new fault diagnosis method is proposed of adaptive demodulated resonance technique based on wavelet packet in multi-information domains. The fault feature vector extracted from multi- information domains is described, signal processing flow of envelope demodulation based on denoising and filtering of wavelet packet is analyzed, the fault diagnosis method of adaptive demodulated resonance technique based on wavelet packet is given, and the method is applied to fault diagnosis of axial piston hydraulic pump. Experiment results show that multi-domain feature vector increases the completeness of the fault information, it is able to obtain good diagnosis effect, and the new fault diagnosis method is able to identify known and unknown faults resonance frequency automatically, the frequency range is narrow, the rate of diagnosis is high.

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16

Zhang, Jie, Jing Shang, and Zhixue Zhang. "Optimization and Control on High Frequency Resonance of Train-Network Coupling Systems." Mathematical Problems in Engineering 2019 (January 20, 2019): 1–10. http://dx.doi.org/10.1155/2019/2190452.

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With the wide application of the electrified railway, high frequency resonances in train-network coupling system often occur, which not only affect the normal operation of trains but also seriously restrict the rapid development of electrified railway. However, the resonance mechanism has not been fully grasped and needs to be solved. First of all, this paper analyzed the new harmonic characteristics of mixed running of alternating current (AC) and direct current (DC) trains in electrified railway. Then, the mechanism of high frequency resonance and the burnout failure reason of the resistor connected with capacitance (RC) branch in the dc train were analyzed. Simulations were carried out to find some basic conclusions and rules. Subsequently, this paper reproduced and analyzed a real case of high frequency resonance accidents of train-network, burnout accident of RC branch of the dc train. Based on the above researches, optimized control methods to avoid the high frequency resonance were introduced. The achievement of this paper provides an important reference and theoretical basis for the comprehensive optimization and control of train-network coupling systems and the resonance suppression measures.

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17

Yan, Jiaquan, Haixin Sun, En Cheng, Xiaoyan Kuai, and Xiaoliang Zhang. "Ship Radiated Noise Recognition Using Resonance-Based Sparse Signal Decomposition." Shock and Vibration 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/6930605.

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Under the complex oceanic environment, robust and effective feature extraction is the key issue of ship radiated noise recognition. Since traditional feature extraction methods are susceptible to the inevitable environmental noise, the type of vessels, and the speed of ships, the recognition accuracy will degrade significantly. Hence, we propose a robust time-frequency analysis method which combines resonance-based sparse signal decomposition (RSSD) and Hilbert marginal spectrum (HMS) analysis. First, the observed signals are decomposed into high resonance component, low resonance component, and residual component by RSSD, which is a nonlinear signal analysis method based not on frequency or scale but on resonance. High resonance component is multiple simultaneous sustained oscillations, low resonance component is nonoscillatory transients, and residual component is white Gaussian noises. According to the low-frequency periodic oscillatory characteristic of ship radiated noise, high resonance component is the purified ship radiated noise. RSSD is suited to noise suppression for low-frequency oscillation signals. Second, HMS of high resonance component is extracted by Hilbert-Huang transform (HHT) as the feature vector. Finally, support vector machine (SVM) is adopted as a classifier. Real audio recordings are employed in the experiments under different signal-to-noise ratios (SNRs). The experimental results indicate that the proposed method has a better recognition performance than the traditional method under different SNRs.

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18

Kremer, Eugen. "The effect of high-frequency stochastic actions on the low-frequency behaviour of dynamic systems." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2192 (January 18, 2021): 20200242. http://dx.doi.org/10.1098/rsta.2020.0242.

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The dynamic system described by a finite number of first-order differential equations is considered. The right side of each equation is a sum of a slow, deterministic and, in the general case, nonlinear function of dynamic variables and a stochastic excitation. The stochastic action is a superposition of a finite number of independent random processes with coefficients depending on dynamic variables and slow time. The problem statement is oriented to applications in the field of driven systems. The analysis is based on the concept of vibration mechanics proposed by I. I. Blekhman. The modified method of direct separation of slow and fast motions uses the explicit introduction of a small parameter and some ideas of the two-scale technique. The general formulas for vibrational forces (or fluxes) are obtained. These additional terms appear in the resulting system for averaged motion instead of the stochastic terms to make the averaged system equivalent to the initial stochastic system with respect to slow motions and, in particular, to low-frequency resonances. As an example, the model of a vibration machine for bulk material processing is considered. The stochastic effect is caused by random oscillations of the bulk material mass. It is transformed into a modification of the machine's frequency characteristics leading to a specific stochastic resonance. This article is part of the theme issue ‘Vibrational and stochastic resonance in driven nonlinear systems (part 1)’.

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19

Zhou, Jun Peng, Ren Shan Pang, Gui Fu Yang, Hai Xia Chen, and Lian Ming Wang. "Research on the Quadrature Demodulation-Based Quartz Crystal Microbalance Implementation Method." Applied Mechanics and Materials 620 (August 2014): 214–18. http://dx.doi.org/10.4028/www.scientific.net/amm.620.214.

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In order to overcome the shortcomings of traditional quartz crystal microbalance (QCM) network measuring method, such as high requirements for hardware devices, low measurement speed and high challenge to curve fitting, a method based on the Quadrature Demodulation was proposed to design a rapid and accurate measuring system for QCM parameters, which mainly took the advantages of Quadrature Demodulation to remove the intermediate frequency component while reserve the low frequency component. Furthermore, the effectiveness of this method was proved by contrasting the Matlab simulation results with the actual measurement results based on the modified measuring system, which indicated that the frequency resolution could reach 0.1Hz with high testing speed of 0.02s per cycle, the relative deviations of resonance frequencies were less than 0.01% and the deviation of the differences between series and parallel resonant frequency points was 0.38%.

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20

Kula, Piotr, Konrad Dybowski, Sebastian Lipa, Robert Pietrasik, Radomir Atraszkiewicz, Leszek Klimek, Bartłomiej Januszewicz, and Emilia Wołowiec. "Investigating Fatigue Strength of Vacuum Carburized 17CrNi6-6 Steel Using a Resonance High Frequency Method." Solid State Phenomena 225 (December 2014): 45–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.225.45.

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The bending fatigue strength of 17CrNi6-6 steel subjected to vacuum carburizing with high pressure gas hardening has been measured using a novel high-frequency technique. The test records the changes in resonance and consists of observing resonance frequency changes in a vibrating system with a single degree of freedom as a result of the forming of a fatigue crack. Moreover, a mechanism of fatigue nucleation and propagation in steel hardened by vacuum carburizing is presented.

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21

Lu, Zhenyu, Tingya Yang, and Min Zhu. "Study of the Method of Multi-Frequency Signal Detection Based on the Adaptive Stochastic Resonance." Abstract and Applied Analysis 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/420605.

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Recently, the stochastic resonance effect has been widely used by the method of discovering and extracting weak periodic signals from strong noise through the stochastic resonance effect. The detection of the single-frequency weak signals by using stochastic resonance effect is widely used. However, the detection methods of the multifrequency weak signals need to be researched. According to the different frequency input signals of a given system, this paper puts forward a detection method of multifrequency signal by using adaptive stochastic resonance, which analyzed the frequency characteristics and the parallel number of the input signals, adjusted system parameters automatically to the low frequency signals in the fixed step size, and then measured the stochastic resonance phenomenon based on the frequency of the periodic signals to select the most appropriate indicators in the middle or high frequency. Finally, the optimized system parameters are founded and the frequency of the given signals is extracted in the frequency domain of the stochastic resonance output signals. Compared with the traditional detection methods, the method in this paper not only improves the work efficiency but also makes it more accurate by using the color noise, the frequency is more accurate being extracted from the measured signal. The consistency between the simulation results and analysis shows that this method is effective and feasible.

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22

Zhong, Li Ping. "Research on rotating high-frequency current injection method based on LC resonance network." International Journal of Computer Applications in Technology 64, no. 2 (2020): 143. http://dx.doi.org/10.1504/ijcat.2020.10033914.

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23

Zhong, Li Ping. "Research on rotating high-frequency current injection method based on LC resonance network." International Journal of Computer Applications in Technology 64, no. 2 (2020): 143. http://dx.doi.org/10.1504/ijcat.2020.111607.

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24

Pang, Bo, Heng Nian, Guodong Xu, and Jixing Qiu. "Method of eliminating high frequency resonance of DFIG system connected to weak grid." Journal of Engineering 2017, no. 13 (January 1, 2017): 1793–98. http://dx.doi.org/10.1049/joe.2017.0640.

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25

Wang, Yong, Shunming Li, Chun Cheng, and Xingxing Jiang. "Dynamic Analysis of a High-Static-Low-Dynamic-Stiffness Vibration Isolator with Time-Delayed Feedback Control." Shock and Vibration 2015 (2015): 1–19. http://dx.doi.org/10.1155/2015/712851.

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This paper proposes the time-delayed cubic velocity feedback control strategy to improve the isolation performance of High-Static-Low-Dynamic-Stiffness (HSLDS) vibration isolator. Firstly, the primary resonance of the controlled HSLDS vibration isolator is obtained by using multiple scales method. The equivalent damping ratio and equivalent resonance frequency are defined to study the effects of feedback gain and time delay on the primary resonance. The jump phenomenon analysis of the controlled system without and with time delay is investigated by using Sylvester resultant method and optimization method, respectively. The stability analysis of the controlled system is also considered. Then, the 1/3 subharmonic resonance of the controlled system is studied by using multiple scales method. The effects of feedback gain and time delay on the 1/3 subharmonic resonance are also presented. Finally, force transmissibility is proposed to evaluate the performance of the controlled system and compared with an equivalent linear passive vibration isolator. The results show that the vibration amplitude of the controlled system around the resonance frequency region decreases and the isolation frequency band is larger compared to the equivalent one. A better isolation performance in the high frequency band can be achieved compared to the passive HSLDS vibration isolator.

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26

Broadhead, Michael K. "Oscillating oil drops, resonant frequencies, and low-frequency passive seismology." GEOPHYSICS 75, no. 1 (January 2010): O1—O8. http://dx.doi.org/10.1190/1.3280041.

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A recent passive seismic technology in the oil industry, sometimes referred to as hydrocarbon microtremor analysis (also low-frequency spectroscopy), claims high correlation in some instances between the presence of hydrocarbons and low-frequency spectral anomalies (elevated spectral energy levels) computed from passively recorded seismic data. These observations have been reported for a number of different geographic locations. One of the difficulties in assessing this method is the lack of a physical basis for explaining the empirically observed effects. A potential explanation that has appeared in the literature can be referred to as the resonant amplification model. The main idea of the model is that, because of capillary effects, an oil drop in a rockpore will oscillate at a resonant frequency when driven by the ambient noise field of the earth. This resonance phenomenon is interpreted as a possible source of the spectral anomaly. I examined this model by numerical simulation but was unable to reproduce the amplification effect. I then considered one of the main input parameters, the resonant frequency itself. By computing resonant frequencies using theoretical models from the literature, I found that the resulting values are too high to be consistent with the frequency range of hydrocarbon microtremor analysis. Furthermore, I found that such resonances only exist for little or no viscous damping. When realistic damping is considered, there is no oil-drop resonance effect. The model, at least in its current form, does not appear to provide a promising direction for establishing a physical basis for hydrocarbon microtremor analysis.

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27

Pang, Bo, Feng Li, Hui Dai, and Heng Nian. "High Frequency Resonance Damping Method for Voltage Source Converter Based on Voltage Feedforward Control." Energies 13, no. 7 (April 1, 2020): 1591. http://dx.doi.org/10.3390/en13071591.

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High frequency resonance (HFR) is a subsistent problem which affects the operation of the voltage source converter (VSC) connected to the parallel compensated grid. The appearance of HFR introduces a significant high frequency component in the grid voltage, thereby the operation of VSC system will be seriously affected. For enhancing the operation capability of VSC system, an HFR damping method based on the voltage feedforward control is proposed in this paper, which can reshape the VSC system impedance effectively in a wideband range. Besides, different with the existing HFR damping methods, the proposed method introduces a correction factor instead of the series virtual impedance with fixed value, so that the effect of impedance reshaping is irrelevant to the parameters of controlled object. In addition, this paper analyzes the fundamental control performance of VSC system after equipping the proposed method, for verifying that the proposed method will not worsen the fundamental control. Experimental results are given to validate the effectiveness of the proposed damping method.

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28

Liu, Wenyao, Wei Li, Chenxi Liu, Enbo Xing, Yanru Zhou, Lai Liu, and Jun Tang. "A High-Sensitivity Resonant Magnetic Sensor Based on Graphene Nanomechanical Resonator." Micromachines 13, no. 4 (April 16, 2022): 628. http://dx.doi.org/10.3390/mi13040628.

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This paper presents a novel resonant magnetic sensor consisting of a graphene nanomechanical oscillator and magnetostrictive stress coupling structure, using Si/SiO2 substrate and Fe–Ga alloy, respectively. In this device, the deformation of the Fe–Ga alloy resulting from the external magnetic field changed the surface tension of the graphene, resulting in a significant change in the resonance frequency of graphene. Using the finite element analysis, it could be found that the response of the resonance frequency revealed a good linear relationship with the external magnetic field (along the x-axis) in the range of the 1 to 1.6 mT. By optimizing the sizes of each component of the magnetic sensor, such as the thickness of the Si/SiO2 substrate and the Fe–Ga alloy, and the length of the graphene, the sensitivity could even reach 834 kHz/mT, which is three orders of magnitude higher than conventional resonant magnetic devices. This provides a new method for highly sensitive and miniaturized magnetic sensors.

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29

Liu, Z., and D. Xie. "Finite-amplitude steady-state wave groups with multiple near-resonances in finite water depth." Journal of Fluid Mechanics 867 (March 21, 2019): 348–73. http://dx.doi.org/10.1017/jfm.2019.150.

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Finite-amplitude wave groups with multiple near-resonances are investigated to extend the existing results due to Liu et al. (J. Fluid Mech., vol. 835, 2018, pp. 624–653) from steady-state wave groups in deep water to steady-state wave groups in finite water depth. The slow convergence rate of the series solution in the homotopy analysis method and extra unpredictable high-frequency components in finite water depth make it hard to obtain finite-amplitude wave groups accurately. To overcome these difficulties, a solution procedure that combines the homotopy analysis method-based analytical approach and Galerkin method-based numerical approaches has been used. For weakly nonlinear wave groups, the continuum of steady-state resonance from deep water to finite water depth is established. As nonlinearity increases, the frequency bands broaden and more steady-state wave groups are obtained. Finite-amplitude wave groups with steepness no less than $0.20$ are obtained and the resonant sets configuration of steady-state wave groups are analysed in different water depths. For waves in deep water, the majority of non-trivial components appear around the primary ones due to four-wave, six-wave, eight-wave or even ten-wave resonant interactions. The dominant role of four-wave resonant interactions for steady-state wave groups in deep water is demonstrated. For waves in finite water depth, additional non-trivial high-frequency components appear in the spectra due to three-wave, four-wave, five-wave or even six-wave resonant interactions with the components around the primary ones. The amplitude of these high-frequency components increases further as the water depth decreases. Resonances composed by components only around the primary ones are suppressed while resonances composed by components around the primary ones and from the high-frequency domain are enhanced. The spectrum of steady-state resonant wave groups changes with the water depth and the significant role of three-wave resonant interactions in finite water depth is demonstrated.

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30

Sainz-Aja, Jose, Carlos Thomas, Juan A. Polanco, and Isidro Carrascal. "High-Frequency Fatigue Testing of Recycled Aggregate Concrete." Applied Sciences 10, no. 1 (December 18, 2019): 10. http://dx.doi.org/10.3390/app10010010.

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Concrete fatigue behaviour has not been extensively studied, in part because of the difficulty and cost. Some concrete elements subjected to this type of load include the railway superstructure of sleepers or slab track, bridges for both road and rail traffic and the foundations of wind turbine towers or offshore structures. In order to address fatigue problems, a methodology was proposed that reduces the lengthy testing time and high cost by increasing the test frequency up to the resonance frequency of the set formed by the specimen and the test machine. After comparing this test method with conventional frequency tests, it was found that tests performed at a high frequency (90 ± 5 Hz) were more conservative than those performed at a moderate frequency (10 Hz); this effect was magnified in those concretes with recycled aggregates coming from crushed concrete (RC-S). In addition, it was found that the resonance frequency of the specimen–test machine set was a parameter capable of identifying whether the specimen was close to failure.

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31

KOCH, WERNER. "Acoustic resonances and trapped modes in annular plate cascades." Journal of Fluid Mechanics 628 (June 1, 2009): 155–80. http://dx.doi.org/10.1017/s0022112009006144.

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As a stepping stone towards understanding acoustic resonances in axial flow compressors, acoustic resonances are computed numerically in fixed single and tandem plate cascades in an infinitely long annular duct. Applying perfectly matched layer absorbing boundary conditions in the form of the complex scaling method of atomic and molecular physics to approximate the radiation condition the resonance problem is transformed into an eigenvalue problem. Of particular interest are resonances with zero radiation damping (trapped modes) or very small radiation damping (nearly trapped modes). Such resonances can be excited by wakes from compressor cascades or struts. If the shedding frequency is sufficiently close to an acoustic resonant frequency, the latter may control the vortex shedding causing high-intensity tonal noise or occasionally even blade failure. All resonances are computed for zero mean flow approximating low-Mach-number flows. The influence of various cascade parameters on the resonant frequencies is studied and, whenever possible, our numerical results are compared with published experimental findings.

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32

Rittiplang, Artit, and Wanchai Pijitrojana. "A Low Frequency Wireless Power Transfer Using Parallel Resonance under Impedance Matching." Applied Mechanics and Materials 781 (August 2015): 410–13. http://dx.doi.org/10.4028/www.scientific.net/amm.781.410.

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Nowadays, there are more studies about the wireless power transfer (WPT) for mobile charging, electrical vehicles, implantable biomedical devices, and other applications. They (series resonance) commonly operate at high the self-resonant frequency (f0, several hundred kHz - several MHz ranges) based on magnetic coupling under impedance matching (IM). Operating at high f0 to increase the transfer distance, but high f0 (several MHz ranges) causes other parasitic losses of devices and the effectiveness to humans. In this paper, we propose a new method to design WPT using the parallel resonance under IM at low f0. The two coils are 10-turns with the radius of 6.2 cm. The efficiency (35.77 %) of the system under IM is achieved at the transfer distance of 10 cm and f0=20.388 kHz (low frequency), and the transfer distance can be increased by reducing f0.

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33

Huang, Chengsi, and Hongcheng Li. "Adaptive Notch Filter for Piezo-Actuated Nanopositioning System via Position and Online Estimate Dual-Mode." Micromachines 12, no. 12 (December 8, 2021): 1525. http://dx.doi.org/10.3390/mi12121525.

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Анотація:

Due to the excellent advantages of high speed, high precision, and driving force, piezoelectric actuators nanopositioning systems have been widely used in various micro/nanomachining fields. However, the inherent resonance dynamic of the nanopositioning system generated by the flexure-hinge greatly deteriorates the positioning performance and limits the closed-loop bandwidth. Even worse, the notch filter for eliminating the effect of resonance does not work due to the varying resonant frequency resulting from the external disturbance or mass load. To this end, an adaptive notch filter for piezo-actuated nanopositioning system via position and online estimate dual-mode (POEDM) has been proposed in this paper, which can estimate the varying resonant frequency in real-time and suppress the resonance to improve the closed-loop bandwidth. First, a novel variable forgetting factor recursive least squares (VFF-RLS) algorithm for estimating resonant frequency online is presented, which is robust to the noise and provides the performances of both fast tracking and stability. Then, a POEDM method is proposed to achieve the online identification of the resonant frequency in the presence of noise and disturbance. Finally, a series of validation simulations are carried out, and the results indicate that, the frequency of input signal and the bandwidth have been achieved up to 12.5% and 87.5% of the first resonant frequency, respectively.

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34

Wu, Zhe. "Application of Resonance Demodulation in Rolling Bearing Fault Diagnosis Based on Electronic Resonant." Open Mechanical Engineering Journal 8, no. 1 (December 31, 2014): 922–29. http://dx.doi.org/10.2174/1874155x01408010922.

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The resonance demodulation is an important method in rolling bearing fault feature extraction and fault diagnosis. But in the traditional resonance demodulation method, the resonant frequency of the accelerometer sensing fault information is discrete to some degree due to processing, debugging and installing factors, and the parameters of the band-pass filter are in need for defining beforehand. Meanwhile, as the message generated by bearing early minor failure is often submerged in strong background noise, the SNR is low, the capacity to apply traditional resonance demodulation method to improve the SNR is limited, and the diagnosis effects are not obvious enough. This paper makes use of the equivalence between the electronic resonant system and the mechanical resonance system and conducts resonant gain for sensor output signal using electronic resonators, overcoming the shortcomings of the traditional methods, realizing a UNB high-resolution detection and improved fault feature signal SNR. Besides, the effectiveness of the proposed method has been validated by simulations and experiments, which possess important guiding significance for the engineering practice.

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35

Wang, Fangzhou, Kaipei Liu, Shu Zhu, Qing Huai, Yixing Du, and Dinglin Li. "High-Frequency Resonance Analysis and Stabilization Control Strategy of MMC Based on Eigenvalue Method." IEEE Access 9 (2021): 16305–15. http://dx.doi.org/10.1109/access.2021.3052991.

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36

Buonanno, Giovanni, Adriana Brancaccio, Sandra Costanzo, and Raffaele Solimene. "A Forward-Backward Iterative Procedure for Improving the Resolution of Resonant Microwave Sensors." Electronics 10, no. 23 (November 26, 2021): 2930. http://dx.doi.org/10.3390/electronics10232930.

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This paper sets out a method for improving the resolution of resonant microwave sensors. Usually, the frequency response of these devices is associated with a low quality factor, and consequently with a low resolution in terms of tracking capacity of the resonance frequency shift. Furthermore, since only a finite number of samples can be acquired during the measurement process, the “true” resonance frequency may not be included in the set of acquired data. In order to have an accurate estimate of the resonance frequency, high performance systems with very fine frequency sampling are thus required. To limit these drawbacks, an iterative algorithm is presented which aims to refine the response of resonant microwave sensors by means of a suitable post-processing. The algorithm evaluation is first carried out on synthetic data, and then applied on experimental data referring to a practical scenario, which is inherent to return loss measurements performed by a microwave patch antenna immersed in a water-glucose solution with different concentrations.

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37

Su, Hang, Yu Zhe Wang, Huan Wang, and Zhen Qiang Yang. "DSP Based Novel High Voltage High Frequency Electric Source with Self-tuning Ability." Applied Mechanics and Materials 519-520 (February 2014): 1105–8. http://dx.doi.org/10.4028/www.scientific.net/amm.519-520.1105.

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Design method for a class of novel high voltage high frequency electric source was investigated. This electric source could serve as discharging device for both corona generator and ozone generator. Through self-turning of power angle, the electric source could adjust itself within a certain frequency according to variations of the loads. In this way, the electric source could stay within the state of resonance oscillation so as to maximize discharging efficiency. Using TMS18LF2407A (DSP component produced by TI corporation) as the core device, the electric source guaranteed high working frequency and strong control functions.

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38

Ning, Peng, Guangda Qiao, Xiao Xia, Xiaohui Lu, and Tinghai Cheng. "A stick–slip linear actuator with high speed and nano-resolution by resonance/non-resonance hybrid driving." Review of Scientific Instruments 93, no. 5 (May 1, 2022): 055002. http://dx.doi.org/10.1063/5.0082660.

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To achieve high speed, nano-resolution, and large stroke, a resonance/non-resonance hybrid piezoelectric stick–slip actuator with a lever-type flexure hinge (LTFH-PSSA) is proposed in this work. The actuator can achieve high speed and large stroke in the resonance mode by the stick–slip working principle and achieve nano-resolution in the non-resonant mode by the direct drive working principle. The excitation electrical signals used in the two working modes are the sine waveform and half-sine waveform, respectively. Compared with the traditional sawtooth waveform, the excitation signal of the sine and half-sine waveforms have no sudden change of voltage, which are more conducive to reduce the impact and vibration of the system. Moreover, a series of static analysis and modal analysis of the stator are carried out by the finite element method. The experimental system is built to test the output characteristics of the LTFH-PSSA. In the resonance state by the stick–slip working principle, the impedance analysis and frequency characteristic test of the LTFH-PSSA are carried out, which states that the tested resonance frequency agrees well with the simulated ones. When the locking force, the voltage, and the frequency are 2 N, 100 Vp–p, and 1850 Hz, the speed of the LTFH-PSSA is up to 52.71 mm/s, and the backward motion is suppressed completely as well. In the non-resonance state, the resolution can reach 2.19 nm and 2.69 nm in the forward and backward motion, respectively. So far, the proposed actuator ranks first in speed and resolution among all reported LTFH-PSSAs.

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39

Cai, Longzhu. "UGCPW Structure-Based Embedded Resonator with High Quality Factor for Microwave Substrate Characterization." Electronics 10, no. 2 (January 7, 2021): 113. http://dx.doi.org/10.3390/electronics10020113.

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Анотація:

In this paper, an ungrounded coplanar waveguide-based embedded resonator method for microwave substrate characterization was presented. The effective dielectric constant of the structure and the dielectric constant of microwave substrates can be calculated by the measured resonant frequency. The measured insertion losses at resonant frequencies and the 3 dB bandwidth can be used to determine the loaded and unloaded quality factors, including the dielectric quality factor which is related to dielectric loss tangent. The radiation loss and the extra length due to fringing effect caused by the open-end structure were taken into account to improve the extraction accuracy. The experimental unloaded quality factor of the proposed resonator at resonance order 1 reaches 211.3. The extracted dielectric constant and dielectric loss tangent of Taconic TLY at resonance order 1 are, respectively, 2.218 and 9.286×10−4, which are only 0.018 (relatively 0.82%) and 0.286×10−4 (relatively 3.18%) deviations from the datasheet values, respectively. The proposed resonator method is especially suitable for dielectric characterization of newly developed materials with the difficulty of realizing metal via holes, in which case substrate-integrated-waveguide (SIW) resonator methods are not applicable. When comparing with microstrip resonator methods, the proposed method is of higher quality factor, and it is more reliable and economical as well.

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40

Cai, Longzhu. "UGCPW Structure-Based Embedded Resonator with High Quality Factor for Microwave Substrate Characterization." Electronics 10, no. 2 (January 7, 2021): 113. http://dx.doi.org/10.3390/electronics10020113.

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Анотація:

In this paper, an ungrounded coplanar waveguide-based embedded resonator method for microwave substrate characterization was presented. The effective dielectric constant of the structure and the dielectric constant of microwave substrates can be calculated by the measured resonant frequency. The measured insertion losses at resonant frequencies and the 3 dB bandwidth can be used to determine the loaded and unloaded quality factors, including the dielectric quality factor which is related to dielectric loss tangent. The radiation loss and the extra length due to fringing effect caused by the open-end structure were taken into account to improve the extraction accuracy. The experimental unloaded quality factor of the proposed resonator at resonance order 1 reaches 211.3. The extracted dielectric constant and dielectric loss tangent of Taconic TLY at resonance order 1 are, respectively, 2.218 and 9.286×10−4, which are only 0.018 (relatively 0.82%) and 0.286×10−4 (relatively 3.18%) deviations from the datasheet values, respectively. The proposed resonator method is especially suitable for dielectric characterization of newly developed materials with the difficulty of realizing metal via holes, in which case substrate-integrated-waveguide (SIW) resonator methods are not applicable. When comparing with microstrip resonator methods, the proposed method is of higher quality factor, and it is more reliable and economical as well.

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41

Li, Wei Xin, and He Zhang. "Analysis of Wireless Energy Transfer System Using Magnetic Resonant Coupling." Advanced Materials Research 591-593 (November 2012): 1164–67. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.1164.

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In order to research the relationship between coupling distance and transmission efficiency, study on the transmission characteristics of magnetic resonant coupling for wireless power transmission system, simulation model of wireless power transmission system via magnetic resonance coupling were established based on the theory of two ports network analysis method. The frequency expression of maximum efficiency and the resonant frequency splitting phenomenon condition of a contact-less power transmission system were derived. In a weak coupling at resonance, magnetic resonant coupling can transfer energy with high efficiency. The resonant frequency changes from two to one depending on the critical condition. Until a certain distance, maximum efficiencies are not got. The transmission characteristics of this system were researched by simulation software and experiments. The results show that the transmission characteristics are consistent with theoretical analysis and simulation.

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42

Salpavaara, Timo, Aleksi Hänninen, Jukka Lekkala, and Minna Kellomäki. "Simulation of the Readout Methods for Inductively Coupled High-Frequency Resonance Sensors." Proceedings 2, no. 13 (November 27, 2018): 923. http://dx.doi.org/10.3390/proceedings2130923.

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The readout methods for inductively coupled resonance sensors were simulated using a lumped element model. The purpose of the study was to analyze the readout methods at high frequencies where the self-resonance of the reader coil is likely to interfere with the measurements. Furthermore, the changes in the reading distance cause measurement errors. This phenomenon was studied using simulation. In addition, an algorithm that compensates these errors was tested. The simulation results were in agreement with the test measurements. In addition, the tested error compensation improved the resonance frequency estimates calculated using the simulated and measured data.

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43

Tang, Xiuhui, Daming Zhang, and Hua Chai. "Synthetical Optimal Design for Passive-Damped LCL Filters in Islanded AC Microgrid." Journal of Energy and Power Technology 03, no. 03 (May 19, 2021): 1. http://dx.doi.org/10.21926/jept.2103032.

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In AC microgrid systems, technical issues resulting from the power control effect are the power control method efficiency and the filter resonance since voltage-frequency interference and filtering resonance may cause significant control input reduction and oscillation. A simple and robust solution is to regulate active power flow by adding an optimal passive damping resistor. The optimal LCL filter parameterization process in this paper provides an innovative approach to obtain the optimal quality factor and the optimal damping resistor. The amplitude responses of resonant frequency and high frequency are involved in the cost function. Simulations of various cases are conducted in MATLAB/Simulink. The key advantages of this procedure include flattened admittance peak, weakened high frequency decay, and less damping loss. Through the method in this paper, the optimal passive-damped filter parameters can be calculated in an efficient manner, while the power can be regulated and tracked in a simplified way, and the performance of the control strategy is improved.

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44

Benkouda, S., T. Fortaki, M. Amir, and A. Benghalia. "Resonance of High Tc Superconducting Microstrip Patch in a Substrate-Superstrate Configuration." Advanced Electromagnetics 2, no. 3 (February 14, 2014): 19. http://dx.doi.org/10.7716/aem.v2i3.186.

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The effect of a protecting dielectric superstrate on the resonance of a high Tc superconducting microstrip patch is investigated. The analysis approach is based on the spectral-domain method of moments in conjunction with the complex resistive boundary condition. The complex surface impedance of the superconducting thin film is determined using London’s equation and the two-fluid model of Gorter and Casimir. Numerical results show that the resonant frequency of the high Tc superconducting rectangular patch decreases monotonically with increasing superstrate thickness, the decrease being greater for high permittivity loading.

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45

Ramakrishnan, N., Harshal B. Nemade, and Roy Paily Palathinkal. "Investigation on Resonance Effects of Closely Resonating Nano-Pillars Attached to SAW Resonator." Advanced Materials Research 403-408 (November 2011): 1183–87. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.1183.

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Surface acoustic wave (SAW) sensors form an important class of micro sensors in the microelecto mechanical systems (MEMS) family. Mass loading effect of a sensing medium is one of the prime sensing principles in SAW sensors. Recently we reported mass loading effect of high aspect ratio nano-pillars attached to a SAW resonator. We observed increase in resonance frequency of the SAW resonator in addition to the general mass loading characteristics. We concluded that when the resonance frequency of the pillar is equal to the SAW resonator frequency, the resonance frequency shift caused by mass loading of pillar tends to a negligible value. When such resonating pillars are used as sensing medium in SAW sensors, even a very small change in the dimension of the pillar will offer significant resonance frequency shift. Accordingly, high sensitive SAW sensors can be developed. However in practice it’s quite difficult to manufacture nano-pillars with accurate dimensions such that they resonate with SAW resonator. There is more probability that the pillars may closely resonate with SAW device and offer mass loading. In the present work we have extended our earlier work and performed finite element method (FEM) simulation to study the insight physics of the closely resonating pillars and their effects on acoustic wave propagating on SAW substrate. In this paper we present the discussion on the resonance effects of typical closely resonating pillars on resonance frequency spectrum of the SAW resonator and observations in the pressure wave at the contact surface of the pillar and SAW resonator substrate. It is observed that when the nano-pillars closely resonate with SAW resonator, the pillar oscillations combine with waves propagating in the substrate and introduce beat frequencies. The results and discussion of this paper adds additional information in designing SAW based coupled resonating systems.

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46

Noor, A. M., A. N. Norali, Z. Zakaria, M. Mazalan, and Y. Wahab. "Modelling and Simulation using Finite Element Method of Surface Acoustic Wave Biosensor for Gas Detection Application." Journal of Physics: Conference Series 2071, no. 1 (October 1, 2021): 012022. http://dx.doi.org/10.1088/1742-6596/2071/1/012022.

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Abstract A surface acoustic wave (SAW) sensor detects changes in physical properties such as mass and density on its surface. Compared to other types of sensors, SAW sensor have a good stability, high selectivity and sensitivity, fast response, and low-cost. On the other hand, to design and optimize a SAW biosensor requires a long process including time and cost using conventional methods. Therefore, numerical simulation and computational modelling are useful and efficiently conduct analysis for the SAW biosensor. In this paper, a numerical simulation technique is used to analyse the SAW device sensitivity for the application of gas detection. The SAW biosensor can detect very small mass loading by changing its sensor resonance frequency. The two-dimensional (2D) device model is based on a two-port SAW resonator with a gas sensing layer. We made two design of SAW biosensor device with frequency of 872 MHz and 1.74 GHz. A gas with vary concentration from 1 to 100 ppm were used to determine the change of the device resonance frequency. As a result, the high frequency (1.74 GHz) device, shows that the resonance frequency is shifted larger than to the low frequency (872 MHz) device. In addition, the high frequency device offers five times more sensitivity than the low frequency device. By changing the sensor design, the sensor characteristics such as sensitivity can be altered to meet certain sensing requirements. Numerical simulation provides advantages for sensor optimization and useful for nearly representing the real condition.

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47

El-Bassiouny, Atef F. "The Response of Nonlinear Single-Degree-of-Freedom Systems to Modulated High-Frequency Input." Zeitschrift für Naturforschung A 61, no. 10-11 (November 1, 2006): 541–55. http://dx.doi.org/10.1515/zna-2006-10-1105.

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In this paper we study the response of single-degree-of-freedom with cubic, quartic and quintic nonlinearities to an amplitude-modulated excitation whose carrier frequency is much higher than the natural frequency of the system. The only restriction on the amplitude modulation is that it contains frequencies much lower than the carrier frequency of the excitation. The method of multiple scales is used to derive two coupled first-order ordinary differential equations that describe the evolution of the amplitude and phase with damping, nonlinearities and resonances. The evolution equations are used to determine the steady-state motions, while representative frequency-response curves are presented for each resonance. Stability analysis of the amplitude and phase modulation equations for both cases are performed. The bending of the response curves leads to multi-valued solutions and hence to jump phenomena.

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48

Zhang, Xinyu, Jie Chen, Ruichang Qiu, and Zhigang Liu. "VCT-AOC Comprehensive Method to Suppress High-Frequency Resonance and Low-Frequency Oscillation in Railway Traction Power Supply System." IEEE Access 7 (2019): 152202–13. http://dx.doi.org/10.1109/access.2019.2948210.

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49

Tong, Shuiguang, Yuanyuan Huang, Zheming Tong, and Feiyun Cong. "A novel short-frequency slip fault energy distribution-based demodulation technique for gear diagnosis and prognosis." International Journal of Advanced Robotic Systems 17, no. 2 (March 1, 2020): 172988142091503. http://dx.doi.org/10.1177/1729881420915032.

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To conduct diagnosis and prognosis of gears, this paper introduces a novel short-frequency slip fault energy distribution-based demodulation method. As an essential step of the method, the resonance-based sparse signal decomposition algorithm is firstly employed to obtain the high-resonance part from the raw gear fault signal. To deal with the difficulty in determining the resonance frequency band, we establish a multi-input signal-output model to describe the signal components acquired from a faulty gear. Based on it, the short-frequency slip fault energy distribution graph is defined to locate the center frequency. Besides, the maximum amplitude in the short-frequency slip fault energy distribution graph can be used as a health indicator for prognosis, which is named as fault-induced resonance energy ratio. The effectiveness of the proposed method is validated with both simulated signal and test data. The positive results achieved in both experiments show the perfect property of the methodology for gear fault detection with high noise, especially when the fault is incipient. In addition, by comparing the fault-induced resonance energy ratio values of faulty gears with different severity, it is proved to be a reliable health indicator for gear prognostic.

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50

Li, Demin, and Qingliang Qin. "The invention relates to an intermediate frequency power supply fast start and digital phase locked loop control technology." Journal of Physics: Conference Series 2137, no. 1 (December 1, 2021): 012016. http://dx.doi.org/10.1088/1742-6596/2137/1/012016.

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Abstract Intermediate frequency induction heating is widely used because of its low energy consumption and high thermal efficiency, but the speed of traditional intermediate frequency power supply is slow and its frequency tracking accuracy is limited. In order to maintain the resonant state of the load during the working process of the induction heating power supply and realize the automatic frequency tracking control during the working process. The frequency tracking of the 40kW intermediate frequency power supply is researched, and a method of combining the resonant frequency automatic identification algorithm and the digital phase locked loop frequency tracking control method is proposed. MATLAB simulation and experiment show that the system based on this control method can save the time of searching the load resonance frequency in the initial stage of the power supply, improve the frequency tracking speed, accelerate the dynamic response speed of the system, avoid the failure of frequency lock, and play the role of fast and stable startup.

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