Search results for: Haobin Dong
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Instruments and Experimental Techniques > 2018 > 61 > 1 > 55-64
The parameters in a nuclear magnetic resonance free induction decay (FID) signal contain information that is useful in magnetic field measurement, magnetic resonance sounding and other related applications. A real time sampled FID signal is well modeled as a finite mixture of exponential sequences plus noise. We propose to use the Hilbert-Huang transform (HHT) for noise reduction and characterization,...
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IEEE Sensors Journal > 2017 > 17 > 23 > 7928 - 7934
An automatic wideband 90° phase shifter for optically pumped cesium magnetometer has been investigated experimentally. As an important part of the self-oscillating optically pumped cesium magnetometer detecting circuit, the band and automation of the phase shifter directly affect the continuous measurement of the magnetic field. At the same time, a phase deviation of 1° will cause 1 Hz change of the...
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To improve the traditional electromagnetic induction methods for grounding grid diagnosis, a virtual instrument is proposed to detect weak signals in the harsh and noisy substation electromagnetic environment. The induced electric signal in the coil of wire, containing multi-source and intense noises, is collected by the NI DAQ device. Then virtual phase intensive detectors and digital filters constitute...
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Composite materials have been adopted and become critical in aerospace industry. However, due to the fatigue under continuous loading, the uncertain in structural integrity still remains an unsolved problem. The assessment of structural damage in composite laminates can be achieved by damage location, classification, and quantification. The growth trend of delamination area is one of the most important...
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In order to improve the precision and anti-interference ability of traditional proton magnetometer, and provide reference basis for developing Overhauser magnetometer, a high precision proton magnetometer based on a multi-channel frequency measurement was designed. This paper introduces the basic principle of larmor precession effect, makes a detailed description about the signal disposal system and...
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IEEE Transactions on Instrumentation and Measurement > 2016 > 65 > 4 > 898 - 904
The accuracy of measuring a magnetic field using a proton magnetometer depends on the accuracy of frequency measurement of the free induction decay (FID) signal generated by the proton magnetometer. Increasing the accuracy of frequency measurement could increase the accuracy of measuring magnetic fields. In this paper, we propose a multichannel frequency measurement to improve the accuracy after analyzing...
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This paper focused on modeling and performance analysis of linear inverted pendulum and design and simulation of LQR controller. Main to introduce how to built the mathematic model and the analysis of it's system performance, then design a LQR controller in order to get the much better control. Simulation is done to show the efficiency and feasibility of proposed approach.
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For improving the measuring accuracy and stability of weak magnetic signal of sensor output, based on principles of the proton magnetometer, signal detecting conditioning circuit used analog circuits technology is designed. The feasibility of conditioning circuit is analyzed, the measured data is obtained. In current conditions, The results showed that the signal to noise ratio achieved 30dB.It can...
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Recently, in the field of geological exploration, electromagnetic instruments have been tremendous growth, but they also have some typical shortcomings, such as big size, large power consumption, complex operation and so on. Therefore, base on the current development of electronic technology, this paper has discussed hardware and software design of the electromagnetic data acquisition system, which...
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For UPQC, when source voltage or load current are unbalance or distort, conventional proportional-integral controller on the p-q-r axis can not eliminate steady-state error. To solve this question, an AC equivalent proportional-integral controller in p-q-r axis was proposed. Its principle of eliminating steady-state error to zero was analyzed and a new control strategy by using of it was presented...
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A termite is a dangerous insect that can cause serious damage to civil structures. In southern China, termites have raised a big issue for water conservation dams. Termites cause many serious damages to earth dikes. Hidden damages, caused by long-term activity of termites, are difficult to be detected until it becomes visible, often, too late. The traditional method to find a termitarium is by tracing...
