Dixiang Chen

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Recently, the flux modulation has been presented to deal with the 1/f noise of magnetoresistive (MR) sensors. However, the efficiency of most flux modulation schemes with simple micro- electromechanical-system (MEMS) actuators is not satisfying yet. In this paper, the vertical motion flux modulation (VMFM) is proposed to improve the modulation efficiency.(More)
Accurate measurement of multiphase flows, including gas/solids, gas/liquid, and liquid/liquid flows, is still challenging. In principle, electrical capacitance tomography (ECT) can be used to measure the concentration of solids in a gas/solids flow and the liquid (e.g., oil) fraction in a gas/liquid flow, if the liquid is non-conductive. Electrical(More)
The eddy current probe, which is flexible, array typed, highly sensitive and capable of quantitative inspection is one practical requirement in nondestructive testing and also a research hotspot. A novel flexible planar eddy current sensor array for the inspection of microcrack presentation in critical parts of airplanes is developed in this paper. Both(More)
Multilayer structures are widely used in aircraft fuselage. Because of the interlayer air gap caused by deformation or disbonding, conventional single-frequency eddy current cannot discriminate between second-layer defect signals and gap signals. In this paper, several defects at varied locations (i.e., first-layer surface, first-layer subsurface,(More)
In this paper, based on ARM9 microcontroller S3C2440A and embedded operating system Windows CE, a new nondestructive system was established. The system uses borescope and eddy current testing dual techniques combined into a single probe, which takes advantage of borescope and eddy current testing. The system combines traditional nondestructive testing(More)
Frequency estimation is a fundamental problem in many applications, such as traditional vibration measurement, power system supervision, and microelectromechanical system sensors control. In this paper, a fast and accurate frequency estimation algorithm is proposed to deal with low efficiency problem in traditional methods. The proposed algorithm consists(More)
Cracks often arise in an aeroengine labyrinth disc, which endanger flight security. Non-destructive testing (NDT) must been carried out in the labyrinth disc during the aeroengine working time. In situ detecting cracks in the labyrinth disc, the probe need pass through three layers narrow holes of aircraft skin, engine shell and outlet duct. Ultrasonic,(More)
1∕f noise is one of the main noise sources of magnetoresistive (MR) sensors, which can cause intrinsic detection limit at low frequency. To suppress this noise, the solution of flux concentration and vertical motion modulation (VMM) has been proposed. Magnetic hysteresis in MR sensors is another problem, which degrades their response linearity and detection(More)
In non-destructive testing (NDT) it is important to have a high probability of detection (POD) and reliable characterization of each defect. This can be gained by using several techniques, which leads to an increase in cost and time for testing. Another option is to use several techniques combined into a single probe, in which case data fusion for the(More)