检索结果-内蒙古大学图书馆

International Conference on Electronic measurement and Instruments, ICEMI

作者： Chen Tao Xu Xiaoli The Ministry of Education Key Laboratory of Modern Measurement and Control Technology Beijing Information Science and Technology University Beijing

Wind turbine vibration signal is disturbed by noise, which seriously affects the subsequent fault diagnosis of the turbine. The existing de-noising methods have problems like de-noising principle not clear, operation not easy to carry out, and the de-noising effect not obvious. An adaptive SVD de-noising method based on entropy is put forward. Principle of adaptive SVD de-noising is analyzed, and two main methods of high dimension reconstruction are compared; High dimensional Hankel matrix is reconstructed according to the parity of length time series and the inequality principle and second order difference spectrum of information entropy is proposed to determine de-noising order. The proposed SVD de-noising method is applied in noise analysis of wind turbine vibration signals with comparison to three other SVD de-noising methods. Results show that the second order difference spectrum of information entropy SVD de-noising method has better smoothness, and it is capable to highlight the useful part of the signal, and achieves de-noising purpose effectively. The proposed de-noising method can provide reliable data basis for further fault diagnosis of turbines.

关键词： Noise reduction Vibrations Information entropy Matrix decomposition Wind turbines Noise measurement Vibration measurement

来源：评论

学校读者我要写书评

暂无评论

The forecast method and system of wind turbine operating status trend

The forecast method and system of wind turbine operating sta...

引用

International Conference on Electronic measurement and Instruments, ICEMI

作者： Liu Xiuli Xu Xiaoli Key Laboratory of Modern Measurement & Control Technology of Ministry of Education Beijing Information Science and Technology University Beijing China

The development of wind power industry has put forward higher requirements for the remote monitoring method and system of wind turbines. To effectively guarantee the normal work of the equipment, the processing quality and fault forecast, remote on-line detection and intelligent fault diagnosis system platform is built. Firstly, the theory and method of remote monitoring and maintenance for wind turbines are put forward: dynamic characteristics degradation development tendency weak information signal processing and pre-processing, extraction of dynamic characteristics degradation trend characteristics in long-duration and variable-load state, establishment of trend prediction model and system based on combination of measured big data trend forecast and mechanical dynamic property trend prediction. Then, a remote monitoring system for wind turbines is constructed integrating with sensor technology, dynamic measurement and control technology, signal processing technology, fault pattern recognition technology and artificial intelligence technology. Field application shows that the system can effectively monitor the running status of the fan, achieve the real time alarm and running trend prediction effectively.

关键词： Market research Wind turbines Autoregressive processes Databases Heuristic algorithms Degradation Predictive models

来源：评论

学校读者我要写书评

暂无评论

Application of adaptive median filter and wavelet transform to dongba manuscript images denoising

Application of adaptive median filter and wavelet transform ...

引用

International Conference on Electronic measurement and Instruments, ICEMI

作者： Geng Qiaoman Wu Guoxin Xu Xiaoli Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science & Technology University Beijing China

The images are mixed with a variety of noises in the process of the Dongba Manuscripts digitization. The mixture of Gauss noise and impulse noise is mainly contained in these images. However, the majority of available algorithms can only be implied in removing single noise. As for this situation, a method combining adaptive median filter and wavelet transform is put forward to the noise removal. Meanwhile, simulations are conducted on MATLAB and the result shows that the method can effectively clear the images.

关键词： Adaptive filters Filtering Noise reduction Filtering algorithms Wavelet coefficients

来源：评论

学校读者我要写书评

暂无评论

Canny edge detection based on Open CV

Canny edge detection based on Open CV

引用

IEEE International Conference on Electronic measurement & Instruments

作者： Zhao Xu Xu Baojie Wu Guoxin Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science & Technology University Beijing China

As a traditional edge detection algorithm, Canny operator is widely used and improved. Canny adopts hysteresis threshold, the different values of threshold have great influence on the detection result, but the number can not reflect the detection result intuitively. Four of algorithms are introduced through the use of Open CV programming, the programming can visually display the detection results under different thresholds, which is convenientfor image edge detection.

关键词： Edge detection Canny operator hysteresis threshold Open CV

来源：评论

学校读者我要写书评

暂无评论

Experimental Study for Evacuated Tube Solar Collector with/without a Compound Parabolic Concentrator

Experimental Study for Evacuated Tube Solar Collector with/w...

引用

2017 2nd International Conference on Electrical, Automation and Mechanical Engineering(EAME2017)

作者： Xu Jia Guoxin Wu Tzer-Ming Jeng Sheng-Chung Tzeng Weikai Huang Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science & Technology University Department of Mechanical Engineering Chienkuo Technology University

This paper explored the thermal performance of evacuated tube solar collector with/without a semicircular compound parabolic concentrator(CPC). The configurations of tested systems were:(1) the system without CPC,(2) the system with Model A CPC(3) the system with Model B CPC. This work investigated and compared the thermal efficiency of the evacuated tube solar collector with the CPC by the surface temperature measurements of the evacuated tube solar collector and temperature difference comparison in water tank. Under the following experimental conditions, experimental data indicated that thermal performance of back surface for evacuated tube solar collector can be improved by CPC assuredly. Furthermore, we discovered that two systems with Model A CPC and Model B CPC can improve the efficiency of water temperature in water tank than the system without CPC. The test results showed that CPC can improve thermal efficiency of evacuated tube solar collector effectively while thermal performance was effected by radial size of CPC. To some extent, the bigger the radial size of the CPC, the higher the thermal efficiency. These experimental results provided basis and reference for practical application of Solar Water Heater(SWH).

关键词： evacuated tube solar collector compound parabolic concentrator thermal performance solar water heater(SWH)

来源：评论

学校读者我要写书评

暂无评论

Study on dual-parameter fiber sensor based on LPFG cascaded with FBG structure

引用

Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument 2017年第8期38卷 2047-2054页

作者： Zhang, Wen Liu, Xiaolong He, Wei Zhu, Lianqing Beijing Engineering Research Center of Optoelectronic Information and Instruments Beijing Information Science and Technology University Beijing100016 China Key Laboratory of Modern Measurement Control Technology Ministry of Education Beijing100192 China Beijing Key Laboratory of Optoelectronic Test Technology Beijing Information Science and Technology University Beijing100192 China

A dual-parameter fiber sensor based on Long Period Fiber Grating (LPFG) cascaded with Fiber Bragg Grating (FBG) structure for temperature and strain is presented. The proposed fiber sensor is cascaded with LPFG micromachined by the femtosecond laser and FBG, and there are two dips for the transmission spectrum, namely FBG transmission dip at 1551.9 nm and LPFG transmission dip at 1559.1 nm with the fringe contrast -12.7 dB. The temperature and strain characteristics of the proposed sensor were measured at 30~70℃ and 0~500 μΕ, respectively. Experimental results show that during the warming process, the FBG shows red shift with increasing wavelength, the sensitivity is 15.00 pm/℃, and the linearity is 0.9813;The LPFG shows blue shift with decreasing wavelength, the sensitivity is -11.75 pm/℃, and the linearity is 0.9453. During the cooling process, the FBG shows blue shift with decreasing wavelength, the sensitivity is 18.25 pm/℃, and the linearity is 0.9538;The LPFG shows red shift with decreasing wavelength, the sensitivity is -15.42 pm/℃, and the linearity is 0.9802. During the loading process, the FBG shows red shift with increasing wavelength, the sensitivity is 0.93 pm/μΕ, and the linearity is 0.9915;The LPFG shows blue shift with decreasing wavelength, the sensitivity is -1.51 pm/μΕ, and the linearity is 0.9863. During the unloading process, the FBG shows blue shift with decreasing wavelength, the sensitivity is 0.92 pm/μΕ, and the linearity is 0.9909;The LPFG shows red shift with decreasing wavelength, the sensitivity is -1.51 pm/μΕ, and the linearity is 0.9728. The proposed sensor exhibits high sensitivity and good linearity for dual-parameter measurements. © 2017, Science Press. All right reserved.

关键词： Fiber Bragg gratings

来源：评论

学校读者我要写书评

暂无评论

Research on the cascaded fiber F-P cavity fabricated by femtosecond laser with FBG and its sensing characterization

引用

Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument 2017年第9期38卷 2193-2199页

作者： Zhang, Wen Meng, Fanyong Song, Yanming Lou, Xiaoping Zhu, Lianqing Beijing Engineering Research Center of Optoelectronic Information and Instruments Beijing Information Science and Technology University Beijing100016 China Key Laboratory of Modern Measurement Control Technology Ministry of Education Beijing100192 China Beijing Key Laboratory of Optoelectronic Test Technology Beijing Information Science and Technology University Beijing100192 China

A cascaded fiber Fabry-Perot (F-P) cavity fabricated by femtosecond laser with fiber Bragg grating (FBG) and its sensing characterization has been proposed and its temperature and strain sensing characterization has been studied. During two hours of stability test, the maximum FBG wavelength shift is 0.009 nm, and the maximum FBG power drift is 0.015 dB;the maximum F-P cavity wavelength shift is 0.018 nm, and the maximum F-P cavity power drift is 0.072 dB. When the strain is varying from 0 μΕ to 450 μΕ then back to 0 μΕ, the FBG wavelength peak is shifting towards right then left with the wavelength shift 0.530 4 nm, and the strain sensitivity is 1.17 pm/μΕ with linearity higher than 0.99;the F-P cavity wavelength shift 0.4911nm, and the strain sensitivity is 1.10 pm/μΕ with linearity higher than 0.90. When the temperature is varying from 50℃ to 200℃ then back to 50℃, the FBG wavelength peak is shifting towards right then left with the wavelength shift 1.418nm, and the temperature sensitivity is 10.09 pm/℃ with linearity higher than 0.95;the F-P cavity wavelength shift 1.578 nm, and the strain sensitivity is 10.53 pm/℃ with linearity higher than 0.98. This paper provides not only effective method to solve the problem of single fiber for double parameter measurement, but also reference value for the measurement of multi parameters coupling and decoupling in complex environment. © 2017, Science Press. All right reserved.

关键词： Fiber Bragg gratings

来源：评论

学校读者我要写书评

暂无评论

Ferrographic analysis in wear fault diagnosis for the confluent planetary gear mechanism

Ferrographic analysis in wear fault diagnosis for the conflu...

引用

IEEE International Conference on Electronic measurement & Instruments

作者： Lv Wenxiu Wang Liyong Chen Tao Beijing Information Science and Technology University Key Ministry of Education key Laboratory of Modern Measurement and Control Technology Collaborative Innovation Center of Electric Vehicles in Beijing Beijing China

The principle of ferrography, the method of preparing sample and the procedure of ferrography analysis were introduced. The main morphology characteristics of abrasive in the abnormal wear stage of the confluent planetary gear mechanism were analyzed. It could be found that the fault predicted by the identification and analysis of the abrasive particles image of the oil was coincided with the fault of actual disassembly and assembly detection. That could be good for extending the application offerrography in fault diagnosis.

关键词： Ferrography Oil analysis the confluent planetary gear mechanism

来源：评论

学校读者我要写书评

暂无评论

Optical fiber sensor by cascading long period fiber grating with FBG for double parameters measurement

引用

Optoelectronics Letters 2017年第5期13卷 372-375页

作者： Zhang, Wen Lou, Xiao-ping Dong, Ming-li Zhu, Lian-qing Beijing Engineering Research Center of Optoelectronic Information and Instruments Beijing Information Science and Technology University Beijing China Key Laboratory of Modern Measurement Control Technology Ministry of Education Beijing Key Laboratory for Optoelectronics Measurement Technology Beijing Information Science and Technology University Beijing China Beijing Key Laboratory of Optoelectronic Test Technology Beijing Information Science and Technology University Beijing China

An optical fiber sensor for strain and temperature measurement based on long period fiber grating (LPFG) cascaded with fiber Bragg grating (FBG) structure has been proposed and realized both theoretically and experimentally. Theoretical analysis shows that two microstructures with similar sensitivities cannot be used for double parameters measurement. The LPFG is micromachined by the CO2 laser, and the FBG is micromachined by the excimer laser. For the validation and comparison, two FBGs and one LPFG are cascaded with three transmission valleys, namely FBG1 valley at 1 536.3 nm, LPFG valley at 1 551.2 nm, and FBG2 valley at 1 577.3 nm. The temperature and strain characteristics of the proposed sensor are measured at 45—70 °C and 250—500 με, respectively. The sensitivity matrix is determined by analyzing wavelength shifts and parameter response characterization of three different dips. The proposed optical fiber sensor based on LPFG cascaded with FBG structure can be efficiently used for double parameters measurement with promising application prospect and great research reference value.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A doubly-curved piezoelectric composite with 1–3 connectivity for underwater transducer applications

A doubly-curved piezoelectric composite with 1–3 connectivi...

引用

The 4th International Conference on Advanced Engineering and technology(ICAET 2017)

作者： Yanjun Zhang Likun Wang Lei Qin Qingwei Liao Chao Zhong Beijing Key Laboratory for Sensor Beijing Information Science & Technology University Beijing Key Laboratory for Optoelectronic Measurement Technology Beijing Information Science& Technology University Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing Information Science and Technology University School of Electronic Engineering Beijing University of Posts and Telecommunications

Aim to increase the horizontal and vertical beam width of the high frequency transducer simultaneously, we present a doubly-curved 1-3 piezoelectric composite *** consists of 54%piezoelectric ceramic volume fraction and two phases polymer *** finite element analysis(FEA) is used to evaluate the dynamic response of *** response in water was measured for the doubly-curved composite being considered as underwater *** underwater transducer was fabricated using the doubly-curved 1-3 piezoelectric composite ***-3 dB full angle beam width of transducer is approximately 106° and 36° in the horizontal and vertical plane *** the FEA simulations and experimental results show the potential of a broad covered area of the composite transducer in underwater environment.

关键词： A doubly-curved piezoelectric composite with 1 connectivity for underwater transducer applications

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：