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Modal analysis of acoustic leak signal in pipelines using time-frequency analysis
JIAO Jing-pin, FEI Ren-yuan, HE Cun-fu, WU Bin
《机械工程前沿(英文)》 2006年 第1卷 第2期 页码 146-150 doi: 10.1007/s11465-006-0013-3
Shuai MA, Siyu ZENG, Xin DONG, Jining CHEN, Gustaf OLSSON
《环境科学与工程前沿(英文)》 2014年 第8卷 第1期 页码 128-136 doi: 10.1007/s11783-013-0598-9
关键词: influent load prediction wavelet de-noising power spectrum density autoregressive model time-frequency analysis wastewater treatment
Time-domain and frequency-domain approaches to identification of bridge flutter derivatives
Zhengqing CHEN
《结构与土木工程前沿(英文)》 2009年 第3卷 第2期 页码 173-179 doi: 10.1007/s11709-009-0034-1
关键词: long-span bridges wind-induced vibration flutter derivatives forced vibration test time-domain method frequency-domain method
Peng ZHOU, Zhike PENG, Shiqian CHEN, Yang YANG, Wenming ZHANG
《机械工程前沿(英文)》 2018年 第13卷 第2期 页码 292-300 doi: 10.1007/s11465-017-0443-0
With the development of large rotary machines for faster and more integrated performance, the condition monitoring and fault diagnosis for them are becoming more challenging. Since the time-frequency (TF) pattern of the vibration signal from the rotary machine often contains condition information and fault feature, the methods based on TF analysis have been widely-used to solve these two problems in the industrial community. This article introduces an effective non-stationary signal analysis method based on the general parameterized time–frequency transform (GPTFT). The GPTFT is achieved by inserting a rotation operator and a shift operator in the short-time Fourier transform. This method can produce a high-concentrated TF pattern with a general kernel. A multi-component instantaneous frequency (IF) extraction method is proposed based on it. The estimation for the IF of every component is accomplished by defining a spectrum concentration index (SCI). Moreover, such an IF estimation process is iteratively operated until all the components are extracted. The tests on three simulation examples and a real vibration signal demonstrate the effectiveness and superiority of our method.
关键词: rotary machines condition monitoring fault diagnosis GPTFT SCI
基于频域深度学习的混凝土桥面裂缝实时检测 Article
Qianyun Zhang,Kaveh Barri,Saeed K. Babanajad,Amir H. Alavi
《工程(英文)》 2021年 第7卷 第12期 页码 1786-1796 doi: 10.1016/j.eng.2020.07.026
本文提出了一种基于视觉的混凝土桥面裂缝检测方法,该检测方法将一维卷积神经网络(1D-CNN)与长短期记忆(LSTM)方法集成在图像频域。1D-CNN-LSTM算法经过了数千张开裂以及非开裂的混凝土桥面图像的训练。为了提高训练效率,在预处理阶段,图像首先会被转换到频域,然后使用扁平化的频率数据对算法进行校准。LSTM则被用来提高针对长序列数据开发的网络的性能。所开发模型的训练、验证与测试数据的准确率分别为99.05%、98.9%和99.25%。随后,本文进一步提出了一个运行框架,以便在未来将经过训练的模型应用于大尺寸图像。与现有的深度学习方法相比,本文所提出的1D-CNN-LSTM算法在准确度与计算时间等方面均有卓越的表现。可以预见,1D-CNN-LSTM算法的快速运行使其在实时裂缝检测领域必将大有可为。
A frequency error estimation for isogeometric analysis of Kirchhoff–Love cylindrical shells
《结构与土木工程前沿(英文)》 doi: 10.1007/s11709-023-0006-x
关键词: isogeometric analysis Kirchhoff–Love cylindrical shell free vibration frequency error convergence
Analysis of planetary gear transmission in non-stationary operations
Fakher CHAARI, Mohamed Slim ABBES, Fernando Viadero RUEDA, Alfonso Fernandez del RINCON, Mohamed HADDAR
《机械工程前沿(英文)》 2013年 第8卷 第1期 页码 88-94 doi: 10.1007/s11465-013-0361-8
Planetary gearboxes operate usually in non-stationary conditions generated mainly by variable loads applied to these transmissions. In order to understand the dynamic behavior of planetary gearboxes in such conditions, a mathematic model is developed including driving unit, transmission and load. The variability of load induces a variable speed of the transmission which is taken into account when characterizing the main dynamic parameter of the transmission which is the mesh stiffness function. This function is not periodic following the variability of the transmission speed. The computation of the dynamic response shows an intimate relation between the vibration amplitude level and the load value. As the load increase the vibration level increase. A combined amplitude and frequency modulation is observed which is well characterized using Short Time Fourier transform more suited than the spectral analysis.
关键词: planetary gearbox non-stationary conditions variable load dynamic response time frequency analysis
Xiaowei LUO, Yannick BENICHOU, Suyuan YU
《能源前沿(英文)》 2013年 第7卷 第4期 页码 506-510 doi: 10.1007/s11708-013-0275-5
关键词: aerosol particles collision frequency function coagulation
Fuel variability effect on flickering frequency of diffusion flames
Jizhao LI, Yang ZHANG
《能源前沿(英文)》 2009年 第3卷 第2期 页码 134-140 doi: 10.1007/s11708-009-0034-9
关键词: fuel variability flickering frequency diffusion flames dynamics of combustion
Capacity limitation of nuclear units in grid based on analysis of frequency regulation
Yiping DAI, Pan JIANG, Lin GAO, Weimin KAN, Xiaoqing XIAO, Ge JIN
《能源前沿(英文)》 2012年 第6卷 第2期 页码 148-154 doi: 10.1007/s11708-012-0174-1
关键词: nuclear units capacity overspeed primary frequency control (PFC) second frequency control (SFC)
Oscillation frequency of simplified arterial tubes
Hui AN, Fan HE, Lingxia XING, Xiaoyang LI
《机械工程前沿(英文)》 2009年 第4卷 第3期 页码 300-304 doi: 10.1007/s11465-009-0038-5
关键词: spatial kinematics natural frequency finite element method
Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG
《能源前沿(英文)》 2014年 第8卷 第3期 页码 386-393 doi: 10.1007/s11708-014-0323-9
关键词: high voltage (HV) grid frequency stability parameter identification primary frequency regulation (PFR)
Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer
Lili CHEN, Wu ZHOU
《机械工程前沿(英文)》 2013年 第8卷 第2期 页码 146-149 doi: 10.1007/s11465-013-0260-z
To predict more precisely the frequency of force-balanced micro accelerometer with different bias voltages, the effects of bias voltages on error sensitivity of frequency is studied. The resonance frequency of accelerometer under closed loop control is derived according to its operation principle, and its error sensitivity is derived and analyzed under over etching structure according to the characteristics of Deep Reaction Ion Etching (DRIE). Based on the theoretical results, micro accelerometer is fabricated and tested to study the influences of AC bias voltage and DC bias voltage on sensitivity, respectively. Experimental results indicate that the relative errors between test data and theory data are less than 7%, and the fluctuating value of error sensitivity under the range of voltage adjustment is less than 0.01 μm . It is concluded that the error sensitivity with designed parameters of structure, circuit and process error can be used to predict the frequency of accelerometer with no need to consider the influence of bias voltage.
关键词: Micro-Electro-Mechanical Systems (MEMS) micro accelerometer force-balanced micro accelerometer frequency error sensitivity
《医学前沿(英文)》 2023年 第17卷 第3期 页码 493-502 doi: 10.1007/s11684-022-0946-x
关键词: ALK fusion next-generation sequencing fluorescence in situ hybridization immunohistochemistry variant allele frequency intratumoral heterogeneity targeted therapy
Remote calibration system for frequency based on in-place benchmark
Xiaobin HONG, Guixiong LIU, Zhuokui WU, Xipeng DU,
《机械工程前沿(英文)》 2010年 第5卷 第3期 页码 316-321 doi: 10.1007/s11465-010-0021-1
关键词: remote calibration in-place benchmark frequency comparison global position system (GPS)
标题 作者 时间 类型 操作
Modal analysis of acoustic leak signal in pipelines using time-frequency analysis
JIAO Jing-pin, FEI Ren-yuan, HE Cun-fu, WU Bin
期刊论文
Short-term prediction of influent flow rate and ammonia concentration in municipal wastewater treatment plants
Shuai MA, Siyu ZENG, Xin DONG, Jining CHEN, Gustaf OLSSON
期刊论文
Time-domain and frequency-domain approaches to identification of bridge flutter derivatives
Zhengqing CHEN
期刊论文
Non-stationary signal analysis based on general parameterized time--frequency transform and its application
Peng ZHOU, Zhike PENG, Shiqian CHEN, Yang YANG, Wenming ZHANG
期刊论文
Analysis of planetary gear transmission in non-stationary operations
Fakher CHAARI, Mohamed Slim ABBES, Fernando Viadero RUEDA, Alfonso Fernandez del RINCON, Mohamed HADDAR
期刊论文
Calculation of collision frequency function for aerosol particles in free molecule regime in presence
Xiaowei LUO, Yannick BENICHOU, Suyuan YU
期刊论文
Capacity limitation of nuclear units in grid based on analysis of frequency regulation
Yiping DAI, Pan JIANG, Lin GAO, Weimin KAN, Xiaoqing XIAO, Ge JIN
期刊论文
Parameter identification of interconnected power system frequency after trip-out of high voltage transmission
Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG
期刊论文
Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer
Lili CHEN, Wu ZHOU
期刊论文
Potential unreliability of ALK variant allele frequency in the efficacy prediction of targeted therapy
期刊论文