检索结果-南通市图书馆

Model reduction of fractional impedance spectra for time–frequency analysis of batteries, fuel cells, and supercapacitors

引用

Carbon Energy 2024年第1期6卷 108-141页

作者： Weiheng Li Qiu-An Huang Yuxuan Bai Jia Wang Linlin Wang Yuyu Liu Yufeng Zhao Xifei Li Jiujun Zhang Institute for Sustainable Energy/College of Sciences Shanghai UniversityShanghaiChina Shanxi Key Laboratory of Nanomaterials and Nanotechnology School of Mechanical and Electrical EngineeringXi'an University of Architecture and TechnologyXi'anShaanxiChina Xi'an Key Laboratory of New Energy Materials and Devices School of Materials Science and EngineeringInstitute of Advanced Electrochemical EnergyXi'an University of TechnologyXi'anShaanxiChina

Joint time–frequency analysis is an emerging method for interpreting the underlying physics in fuel cells,batteries,and supercapacitors.To increase the reliability of time–frequency analysis,a theoretical correlation between frequency-domain stationary analysis and time-domain transient analysis is urgently required.The present work formularizes a thorough model reduction of fractional impedance spectra for electrochemical energy devices involving not only the model reduction from fractional-order models to integer-order models and from high-to low-order RC circuits but also insight into the evolution of the characteristic time constants during the whole reduction process.The following work has been carried out:(i)the model-reduction theory is addressed for typical Warburg elements and RC circuits based on the continued fraction expansion theory and the response error minimization technique,respectively;(ii)the order effect on the model reduction of typical Warburg elements is quantitatively evaluated by time–frequency analysis;(iii)the results of time–frequency analysis are confirmed to be useful to determine the reduction order in terms of the kinetic information needed to be captured;and(iv)the results of time–frequency analysis are validated for the model reduction of fractional impedance spectra for lithium-ion batteries,supercapacitors,and solid oxide fuel cells.In turn,the numerical validation has demonstrated the powerful function of the joint time–frequency analysis.The thorough model reduction of fractional impedance spectra addressed in the present work not only clarifies the relationship between time-domain transient analysis and frequency-domain stationary analysis but also enhances the reliability of the joint time–frequency analysis for electrochemical energy devices.

关键词： battery,fuel cell,supercapacitor fractional impedance spectroscopy model reduction time-frequency analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

time-frequency analysis of internal waves generated by a towed and self-propelled submerged body model

引用

Journal of Hydrodynamics 2023年第6期35卷 1191-1207页

作者： Yu-hang Li Fei-yu Chen Li-ping Qin Ke Chen Yun-xiang You Zhengzhou Electromechanical Engineering Research Institute Zhengzhou450015China Henan Key Laboratory of Underwater Intelligence Equipment Zhengzhou450015China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China Yazhou Bay Institute of Deepsea Technology Shanghai Jiao Tong UniversityShanghai200240China

The spectrogram,based on a short-time Fourier transform,can visualize the time-dependent frequency spectrum of waves and is easy to compute.This time-frequency analysis method provides crucial information about waves generated by moving vessels and has been utilized to analyze Kelvin ship waves and internal waves.To further study the internal waves induced by a submerged body,an experiment is conducted for the towed and self-propelled SUBOFF model in a stratified fluid.The internal wave elevation signals are captured using electronic conductivity probes.Comparing with the calculation results of theoretical model,the high-frequency component of internal waves is identified.The high-frequency component has the exact same characteristics in both the towed and self-propelled model experiment and is consistent with the theoretical results for all Froude numbers.Therefore,this component is composed mainly of lee waves.Through spectral characteristics identification,a low-frequency component is discovered in the spectrogram in addition to the lee wave component.The intensity of the low-frequency component is tightly related to the vortex structure behind the submerged body.The vortex structure depends on the net momentum imparted by the submerged body.Therefore,this component is composed mainly of wake waves induced by the vortex structure.

关键词： Stratified fluid internal waves submerged body experimental study time-frequency analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

time-frequency analysis of Li solid-phase diffusion in spherical active particles under typical discharge modes

引用

Journal of Energy Chemistry 2022年第4期31卷 209-224页

作者： Qiu-An Huang Yuxuan Bai Liang Wang Juan Wang Fangzhou Zhang Linlin Wang Xifei Li Jiujun Zhang Institute for Sustainable Energy/College of Science Shanghai UniversityShanghai 201800China Shaanxi Key Laboratory of Nanomaterials and Nanotechnology School of Mechanical and Electrical EngineeringXi’an University of Architecture and TechnologyXi’an 710055ShaanxiChina Institute of Materials/School of Materials Science and Engineering Shanghai UniversityShanghai 200072China Xi’an Key Laboratory of New Energy Materials and Devices Institute of Advanced Electrochemical Energy&School of Materials Science and EngineeringXi’an University of TechnologyXi’anShaanxi 710048China

Li transient concentration distribution in spherical active material particles can affect the maximum power density and the safe operating regime of the electric vehicles(EVs). On one hand, the quasiexact/exact solution obtained in the time/frequency domain is time-consuming and just as a reference value for approximate solutions;on the other hand, calculation errors and application range of approximate solutions not only rely on approximate algorithms but also on discharge modes. For the purpose to track the transient dynamics for Li solid-phase diffusion in spherical active particles with a tolerable error range and for a wide applicable range, it is necessary to choose optimal approximate algorithms in terms of discharge modes and the nature of active material particles. In this study, approximation methods,such as diffusion length method, polynomial profile approximation method, Padé approximation method,pseudo steady state method, eigenfunction-based Galerkin collocation method, and separation of variables method for solving Li solid-phase diffusion in spherical active particles are compared from calculation fundamentals to algorithm implementation. Furthermore, these approximate solutions are quantitatively compared to the quasi-exact/exact solution in the time/frequency domain under typical discharge modes, i.e., start-up, slow-down, and speed-up. The results obtained from the viewpoint of time-frequency analysis offer a theoretical foundation on how to track Li transient concentration profile in spherical active particles with a high precision and for a wide application range. In turn, optimal solutions of Li solid diffusion equations for spherical active particles can improve the reliability in predicting safe operating regime and estimating maximum power for automotive batteries.

关键词： Li solid-phase diffusion Discharge mode Approximate algorithm Quasi-exact/exact solution time-frequency analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Novel Doppler frequency Extraction Method Based on time-frequency analysis and Morphological Operation

引用

Journal of Beijing Institute of Technology 2006年第4期15卷 443-447页

作者：侯舒娟吴嗣亮 School of Information Science and Technology Beijing Institute of Technology Beijing 100081 China

A novel method of Doppler frequency extraction is proposed for Doppler radar scoring systems. The idea is that the time-frequency map can show how the Doppler frequency varies along the time-line, so the Doppler frequency extraction becomes curve detection in the image-view. A set of morphological operations are used to implement curve detection. And a map fusion scheme is presented to eliminate the influence of strong direct current （DC） component of echo signal during curve detection. The radar real-life data are used to illustrate the performance of the new approach. Experimental results show that the proposed method can overcome the shortcomings of piecewise-processing-based FFT method and can improve the measuring precision of miss distance.

关键词： Doppler frequency time-frequency analysis morphological operation miss distance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A New Optimization Neural Network for High Resolution time-frequency analysis

引用

电路与系统学报 1997年第1期 1-7页

作者： Z.S. Wang,Y.S.Xia,J.D.Z. Chen,W.H.Li,Z.Y.He,(Dept. of Radio Engineering, Southeast University, Nanjing, 210096)(Dept. of Mathematics,Nanjing University of Posts & Telecommunications)(Institute for Healthcare Researc, Baptist Medical Center, Oklahoma City,

The authors present a new optimization neural network, which can be called as constrained smallest l1-norm neural network (CSl1NN), to implement the Basis Pursuit(BP)[1][2][3]for high resolution time-frequency analysis. As the new and generalized one of the communities of overcomplete signal representations, the BP is considered as a large-scale linear programming problem. In contrast with the Simplex-BP or Interior-BP in [2],the proposed CSl1NN-BP dose not double the optimizing scale and can be implemented in real time through hardware. Taking non-stationary artificial signals and Electrogastrograms (EGGs) to test, our simulations show that the CSl1 NN presents an excellent convergence performance for a wide range of time-frequency(TF)dictionaries and has a higher joint TF resolution not only than the traditional Wigner Distribution (WD), but also than recently rising other overcomplete representation methods, such as Method of Frames (MOF)[9], Best Orthogonal Basis (BOB)[10] and Matching Pursuit (MP)[4]. Combining the high resolution with the fast implementation,the CSl1NN-BP will be very promising for on-line time frequency analysis of various kinds of non-stationary signals,such as linear chirp,qUadric chirp,bumps etc., and medical signals,such as ECG,EEGand EGG,etc., with high quality.

关键词： Neural network Optimization Overcomplete signal representation Basis pursuit Wavelet time-frequency analysis

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Detection and Delineating of Hydrocarbon Contaminants by Using time and frequency analysis of Ground Penetrating Radar

引用

Journal of Geoscience and Environment Protection 2021年第12期9卷 35-56页

作者： José Vicente Fuente Research & Develop Department Geozone Asesores SL Bétera Spain

This paper provides the results of using ground penetrating radar (GPR) method to detect hydrocarbon products (diesel and gasoline) in a controlled lab test. The work addresses the environmental problem generated by the uncontrolled leakage of hydrocarbon products and the subsequent contamination of plumes in the subsoil. Most of the research proposes the geophysical techniques to evaluate the plumes but some controversial were discussed on how it affected the electrical and dielectric response depending on the excitation of the non-invasive method. The present work focuses on a comparative analysis of some signal attributes of the GPR traces to determine under what premises the detection is properly done. These signal attributes were from the time and frequency domain as attenuation coefficient, instantaneous amplitude and frequency have been considered to analyze three different soil samples. The laboratory tests consist of buried liquid (total hydrocarbon of petroleum, so called TPH) bags in the soil sample boxes reveal the range of target detection and consistency of data on the controlled test regarding the dielectric soil characterization and the delimiting position and depth. Instantaneous amplitude and time-frequency shift are revealed as promising signal attributes to accurate detection of the TPH presence. Numerical simulation data were also carried out to interpret the signal reflecti

关键词： time-frequency analysis Instantaneous Amplitude GPR Survey Hydrocar-bon Products

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Application of Wavelet Packet De-noising in time-frequency analysis of the Local Wave Method

引用

International Journal of Plant Engineering and Management 2003年第4期8卷 233-238页

作者： LI Hong kun, MA Xiao jiang, WANG Zhen, ZHU Hong Institute of Vibration Engineering, Dalian University of Technology, Dalian 116024, P.R.China Institute of Vibration Engineering Dalian University of Technology Dalian 116024 P.R.China

The local wave method is a very good time-frequency method for nonstationaryvibration signal analysis. But the interfering noise has a big influence on the accuracy oftime-frequency analysis. The wavelet packet de-noising method can eliminate the interference ofnoise and improve the signal-noise-ratio. This paper uses the local wave method to decompose thede-noising signal and perform a time-frequency analysis. We can get better characteristics. Finally,an example of wavelet packet de-noising and a local wave time-frequency spectrum application ofdiesel engine surface vibration signal is put forward.

关键词： local wave time-frequency analysis wavelet packet de-noising signal-noise-ratio

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Three-dimensional reconstruction of precession warhead based on multi-view micro-Doppler analysis

引用

Journal of Systems Engineering and Electronics 2024年第3期35卷 541-548页

作者： ZHANG Rongzheng WANG Yong MAO Jian School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China Laboratory of Pinghu Pinghu 314200China

The warhead of a ballistic missile may precess due to lateral moments during release. The resulting micro-Doppler effect is determined by parameters such as the target's motion state and size. A three-dimensional reconstruction method for the precession warhead via the micro-Doppler analysis and inverse Radon transform(IRT) is proposed in this paper. The precession parameters are extracted by the micro-Doppler analysis from three radars, and the IRT is used to estimate the size of targe. The scatterers of the target can be reconstructed based on the above parameters. Simulation experimental results illustrate the effectiveness of the proposed method in this paper.

关键词： time-frequency analysis inverse Radon transform(IRT) precession warhead

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Design and Optimization of Kernel Function in time-frequency analysis

Design and Optimization of Kernel Function in Time-Frequency...

引用

作者： Zi-wen ZHOU Guo-bao RU Liang-cai GAN School of Electronic Information Wuhan University

The time-frequency distribution reflects the frequency energy distribution of the signal in different time periods, and the time-frequency analysis can effectively extract the relevant characteristic parameters of the signal. Aiming at the difficulty of regulation of time-frequency distribution kernel function, poor frequency aggregation and weak ability to suppress cross-terms, this paper proposes a kernel function with four parameters. By selecting the kernel function parameters, on the one hand, the core function passband and transition band can be effectively controlled to achieve the ideal filtering effect, and on the other hand, the interference between signal components is greatly suppressed, and the time-frequency aggregation is further improved. At the same time, the kernel function parameters are optimized by using the third-order Renyi information, so that the time-frequency distribution performance and the filtering effect are optimized, which lays a foundation for effectively extracting the relevant characteristic parameters of the signal.

关键词： time-frequency analysis Kernel function Reny

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Doppler frequency Extraction of Radar Echo Signal based on time-frequency analysis and Morphological Operation

Doppler Frequency Extraction of Radar Echo Signal based on T...

引用

第七届国际信号处理会议

作者： Shujuan Hou Siliang Wu Shufen Ma (Department of Electronic Engineering, Beijing Institute of Technology, Beijing, China 100081)

The extraction of Doppler frequency is a key problem in Doppler radar scoring systems. This paper presents a new method for Doppler frequency extraction based on time-frequency analysis and morphol

关键词： Doppler frequency time-frequency analysis morphological operation

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：