Chen Y.-Q.,Yanshan University |
Chen Y.-Q.,Shenyang Academy of Instrumentation Science Co |
Wang Y.-T.,Yanshan University |
Tang B.-W.,Yanshan University |
And 2 more authors.
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2016
A method of current single-phase fault line selection based on mathematical morphology and generalized S-transform is proposed. Mathematical morphology is a novel nonlinear filtering technique. Considering the signal characteristics of the power system, a linear structural element is selected. Not only can eliminate the burr shape noise, but also maintain the shape of the signal well. Generalized S-transform overcomes the shortcomings of the basic wavelet bases fixed in the S transform, and has a better frequency resolution. The signal was filtered by the mathematical morphological first. Then the generalized S-transform is used to analyze fault signals to get the modulus frequency matrix. Finally the energy characteristics modulus frequency matrix is analyzed to select the fault line. Simulation results show that the method could select fault line accurately under different working conditions of distribution network. © 2016, Acta Metrologica Sinica Press. All right reserved.
Chen Y.,Yanshan University |
Chen Y.,Shenyang Academy of Instrumentation Science Co |
Wang Y.,Yanshan University |
Li H.,North China Institute of Aerospace Engineering |
And 2 more authors.
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2015
This paper focuses on the noise floor of piezoelectric accelerometer, takes the piezoelectric transducer and charge amplifier as study objects, and establishes the mechanical model of piezoelectric transducer single degree of freedom spring-mass-damping mechanical resonance system and the electrical model of piezoelectric element. The Junction Field Effect Transistor (JFET) is taken as the core element to study the main noise source in the circuit, and establish the respective noise model for each source. The construction method of En-In noise model is used to make the inner noise source of the charge amplifier equivalent to the input port; meanwhile, the Y-Δ transformation theory is introduced into the noise analysis of T type bias network. The noise model is used to deduce the noise spectrum density expression of the piezoelectric accelerometer. The experiment data and the theoretical calculation values obtained from the expression were compared, which verifies the effectiveness and correctness of the expression. Using this expression, the key factors affecting the accelerometer noise are analyzed, the low noise design principle of the accelerometer is summarized, which provides a theoretical basis for improving the noise-signal ratio of the accelerometer. ©, 2015, Science Press. All right reserved.
Yang Y.B.,Dalian Maritime University |
Liu Y.,Dalian Maritime University |
Kong X.F.,Shenyang Academy of Instrumentation Science Co
Advanced Materials Research | Year: 2014
Using SPSS software and time series analysis method, we research on the influence of demographic dividend factors on Liaoning province dependency ratio indicators. The results found that a major determinant of regional economy, which is in the demographic dividend period, is per capita consumption and the dependency ratio. © (2014) Trans Tech Publications, Switzerland.
Ma Y.,Shenyang Academy of Instrumentation Science Co |
Bai X.F.,Shenyang Academy of Instrumentation Science Co
Applied Mechanics and Materials | Year: 2014
The precision dicing machine is adopted as the research object in the paper, the technology of grating sensor is selected to overcome the shortcoming of traditional compensation methods for inaccurate return compensate. The measurement is done through the grating sensor, with the aid of neural network feedback method, the fitting and compensation of the data measured by the grating sensor is completed, the deviation caused by vibration during the spindle run-time is eliminated. And the purpose of improving the precision of spindle is realized. © (2014) Trans Tech Publications, Switzerland.
Adewale I.D.,Northumbria University |
Tian G.Y.,Northumbria University |
Tian G.Y.,University of Electronic Science and Technology of China |
Dong S.H.,Shenyang Academy of Instrumentation Science Co |
And 3 more authors.
Studies in Applied Electromagnetics and Mechanics | Year: 2015
This paper focuses on defect characterisation independent of the lift-off effects using lift-off point of intersection (LOI) and the separation of these two parameters in pulsed eddy current (PEC) measurements for ferrous and nonferrous materials. It reveals, amongst other things, that the first order derivative of the normalised PEC response maintains the LOI feature, which otherwise is not apparent in ferromagnetic materials using current methods; lift-off effects in ferrous materials vary strongly with the second order derivative of the normalised PEC response and the LOI can be used for defect estimation in a magnetic sensor-based PEC. These two characteristics provide a means of separating lift-off effects from the defect. © 2015 The authors and IOS Press. All rights reserved.