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Lumped parameter model for resonant frequency estimation of a thermoacoustic engine with gas-liquid coupling oscillation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第3期12卷 232-237页

作者： Ke TANG Tian LEI Xiao-gang LIN Tao JIN Yu ZHANG Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China

Gas-liquid coupling oscillation is a novel approach to reducing the resonant frequency and to elevating the pressure amplitude of a thermoacoustic *** a thermoacoustic engine is used to drive low-frequency pulse tube refrigerators,the frequency matching between the thermoacoustic engine and the refrigerator plays an important *** on an acoustic-electric analogy,a lumped parameter model is proposed to estimate the resonant frequency of a standing-wave thermoacoustic engine with gas-liquid coupling ***,a simplified lumped parameter model is also developed to reduce the computation *** resonant frequency dependence on the mean pressure,the gas space volume,and the water column length is computed and *** impact of different working gases on the resonant frequency is also *** effectiveness of the models is validated by comparing the computed results with the experimental data of the gas-liquid coupling oscillation *** increase in the mean working pressure can lead to a rise in the resonant frequency,and a lower resonant frequency can be achieved by elongating the liquid *** comparison with nitrogen and argon,carbon dioxide can realize a lower frequency due to a smaller specific heat ratio.

关键词： Thermoacoustic engine Gas-liquid coupling oscillation Acoustic-electric analogy resonant frequency

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Computation of resonant frequency of Gap-coupled Ring Microstrip Antennas

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International Journal of Automation and computing 2014年第6期11卷 671-675页

作者： Pradeep Kumar Department of Electronics and Communication Engineering Jaypee University of Information TechnologyWaknaghat- 173234 India

In this paper, an analytical model for computing the resonant frequency of the gap-coupled ring microstrip patch antennas is developed. The analytical model is based upon the cavity model along with circuit theory. Using the field expressions and boundary conditions, the transcendental equation for the structure is developed. The analytically computed results are compared with the simulated results. The simulation work is carried out by using computer simulation technology(CST) microwave studio *** comparison between simulated and computed results shows good agreement.

关键词： Ring microstrip antenna gap-coupling resonant frequency analytic model parasitic element

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Phase Coherence Method for the resonant frequency Analysis of the Modified Dumbbell-Shaped Defected Ground Structure Resonator on Coplanar Waveguide

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Chinese Journal of Electronics 2014年第2期23卷 415-418页

作者： WANG Jun NING Huansheng DONG Han HONG Tao XIONG Qingxu MAO Lingfeng School of Electronic and Information Engineering Beihang University Institute of Intelligent Structure and System Soochow University

A The resonance of the Modified dumbbellshaped defected ground structure(MD-DGS) resonator on coplanar waveguide is investigated systematically based on the phase coherence of electromagnetic *** the analysis of two presented interference modes,the resonant frequencies can be fully predicted,and the physical understanding behind these resonances is clearly *** proposed analysis is verified by the simulation and measurement results of the MD-DGS *** the electric field distribution and the Poynting vector distribution of the MD-DGS resonator at the resonant frequencies further demonstrate the validity of the theoretical analysis.

关键词： Phase coherence resonant frequency Defected ground structure

A NOVEL METHOD FOR EVALUATING THE resonant frequency OF A MICROSTRUCTURE

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A NOVEL METHOD FOR EVALUATING THE RESONANT FREQUENCY OF A MI...

Research on Low-frequency Multi-Directional Piezoelectric Energy Harvester with Combined Cantilever Beam

庆祝中国力学学会成立50周年暨中国力学学会学术大会’2007

作者： KANG Xin~* HE Xiaoyuan~+ *(Department of Applied Mechanics,Nanjing University of Science and Technology,Nanjing 210094,China) +(Research Institute of Engineering Mechanics,Southeast University,Nanjing 210096,China)

A novel optical method for evaluating the natural frequency and the quality factor(Q) of a microstructure is proposed in *** proposed method is based on ultrasonic wave excitation which is a non-contact technique and does not impose undefined *** images of a microstructure vibrated ultrasoniclly are captured by a CCD camera at different *** vibrational amplitudes of the microstructure are

关键词： microstructure ultrasonic wave excitation resonant frequency quality factor edge detection wavelet transform

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Chinese Journal of Electronics 2025年第1期34卷 156-164页

作者： Qingying Ren Yuxuan Liu Debo Wang College of Electronic and Optical Engineering Nanjing University of Posts and Telecommunications College of Integrated Circuit Science and Engineering Nanjing University of Posts and Telecommunications

In order to realize the collection and utilization of low-frequency vibration energy, a multi-directional piezoelectric energy harvester is proposed, which consists of a lower circular arc beam and an upper L-shaped *** the lower and upper beams can achieve multi-directional energy harvesting, and the upper L-shaped beam can also act as a mass block to reduce the resonant frequency. The structure of this energy harvester is optimized. Four different structures are studied with varying combination angles between the upper and lower layers to acquire data related to resonant frequency, vibration shape, stress distribution, open-circuit voltage, and output power. Additionally, the performance of each structure is comprehensively prepared and measured to verify its effectiveness. The optimal structure achieved a resonant frequency of 11 Hz and an output power of 57.1 μW at the optimal load resistance of 201 kΩ. Consequently, this work provides valuable reference for the study of low-frequency vibration energy harvesting technology.

关键词： Vibrations Resistance Wireless communication Wireless sensor networks Shape resonant frequency Structural beams Energy harvesting Power generation Stress

Biomechanical properties of ready-to-harvest rapeseed plants:Measurement and analysis

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Information Processing in Agriculture 2023年第3期10卷 391-399页

作者： Guangchao Zhan Wangyuan Zong Lina Ma Junyi Wei Wei Liu College of Engineering Huazhong Agricultural UniversityWuhan 430070PR China Key Laboratory of Agricultural Equipment in Middle-lower Reaches of the Yangtze River Ministry of Agriculture and Rural AffairsWuhan 430070PR China

A large loss occurs in the combine harvesting of rapeseeds due to the fragility of rapeseed pods,and all the more so with the vibration of the combine header and the collision between the header and *** loss is greatly affected by the biomechanical properties of ready-to-harvest rapeseed *** understand the mechanism of pod cracking and seed loss and to propose measures for alleviating them,it is needed to study the biomechanical properties of ready-to-harvest rapeseed *** this end,“Huayouza 62”,a widely planted rapeseed variety in central China,was selected to study the biomechanical properties,including pod-cracking resistance,main stem-shearing resistance and resonant frequencies,of whole *** results showed that the distribution of pod-cracking resistance forces was 1.333–6.100 N in the mature stage,and the pod width and thickness had a significant influence on the cracking *** main influencing factor of the main stem-shearing resistance was the stem diameter.A thicker main stem resulted in a larger shearing resistance force but a smaller shear *** moisture contents of the main stems varied from 47.71%to 76.13%.However,the varying moisture contents did not show a significant impact on the shearing *** resonant frequencies of whole rapeseed plants ready for harvest ranged from 6.5 Hz to 7.5 Hz,which was close to the excitation frequency of the cutter bar on the 4LL-1.5Y *** study lays a foundation for improving the design and construction of harvesting devices for rapeseed plants to reduce seed loss.

关键词： Rapeseed pod Cracking resistance Shearing resistance resonant frequency Rapeseed harvesting

A Phase Readout Method for Wireless Passive Sensor Used in Pressure Measurement System

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Chinese Journal of Electronics 2015年第4期24卷 702-708页

作者： HONG Yingping LIANG Ting ZHENG Tingli ZHANG Hairui LIU Wenyi XIONG Jijun Key Laboratory of Instrumentation Science & Dynamic Measurement Ministry of Education North University of China Science and Technology on Electronic Test & Measurement Laboratory North University of China

A phase difference detection method used for reading the resonant frequency through mutual coupling is designed to meet the pressure measurement in harsh environments, and a testing device of integrated modular by developing the hardware circuits is *** and discussion of the novel theoretical model in the phase readout system is presented, and a pressure test platform based on the phase difference detection is also established, which is to measure the frequency of a LC resonant sensor on the basis of 96% alumina ceramic substrate. The experimental results show that the proposed phase difference readout system presents sweep-frequency detection in the range of 1–100MHz bandwidth, and a high frequency resolution of 0.006 MHz. Sensitivity of the sensor is approximately 0.225 MHz/bar from 1 bar to 2 bar. The accuracy and functionality of the phase readout system have emphasized a wider engineering application range, so that we can make it possible that the wireless passive LC resonant sensor revolves well in practical engineering occasions outside the laboratory environment.

关键词： LC resonant sensor resonant frequency Phase difference detection Pressure test

The Multi-field Coupled Vibration Analysis of AT-Cut Quartz Crystal Resonators with Parallelism Error

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Acta Mechanica Solida Sinica 2023年第2期36卷 349-360页

作者： Mengjie Li Nian Li Peng Li Dianzi Liu Iren EKuznetsova Zhenghua Qian Tingfeng Ma State Key Laboratory of Mechanics and Control of Mechanical Structures College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China Shenzhen Research Institute Nanjing University of Aeronautics and AstronauticsShenzhen 518063China School of Engineering University of East AngliaNorwich NR47TJUK Kotel’nikov Institute of Radio Engineering and Electronics of RAS MoscowRussia Key Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo 315211China

During the fabrication of quartz crystal resonators(QCRs),parallelism error is inevitably generated,which is rarely *** order to reveal the influence of parallelism error on the working performance of QCRs,the coupled vibration of a non-parallel AT-cut quartz crystal plate with electrodes is systematically studied from the views of theoretical analysis and numerical *** two-dimensional thermal incremental field equations are solved for the free vibration analysis via the coefficient-formed partial differential equation module of the COMSOL Multiphysics software,from which the frequency spectra,frequency–temperature curves,and mode shapes are discussed in ***,the piezoelectric module is utilized to obtain the admittance response under different *** is demonstrated that the parallelism error reduces the resonant ***,symmetry broken by the non-parallelism increases the probability of activity dip and is harmful to QCR’s thermal ***,if the top and bottom surfaces incline synchronously in the same direction,the influence of parallelism error is *** conclusions achieved are helpful for the QCR design,and the methodology presented can also be applied to other wave devices.

关键词： Quartz crystal resonators Parallelism error resonant frequency Mode coupling Admittance

High sum-frequency generation in dielectric/antiferromagnet/Ag sandwich structures

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Chinese Physics B 2014年第5期23卷 556-562页

作者：付淑芳梁红周胜王选章 Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal University School of Electric Engineering Harbin University of Science and Technology School of Science Harbin University

We present a method to increase the sum-frequency （SF） outputs in dielectric/antiferromagnet（AF）/Ag sandwich structures for a fixed input power. Two incident waves simultaneously illuminate the upper surface, one is oblique and the other is normal to it. Numerical calculations based on the SiO2/MnF2/Ag and ZnF2/MnF2/Ag structures show that the SF outputs on the upper film increase a few times as compared to those of a single AF film when the thickness of the AF film is one-quarter of the vacuum wavelength. Moreover, the SF outputs generated near the higher resonant frequency will be higher than those obtained near the lower resonant frequency. An optimum AF film thickness is achieved through investigating its effect on the SF outputs in the two different dielectric sandwich structures.

关键词： sum-frequency generation antiferromagnetic film resonant frequency nonlinear response

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