The pulsed eddy current (PEC) technique generates responses over a wide range of frequencies, containing more spectral coverage than traditional eddy current inspection. Eddy current pulsed thermography (ECPT), a newl...
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The pulsed eddy current (PEC) technique generates responses over a wide range of frequencies, containing more spectral coverage than traditional eddy current inspection. Eddy current pulsed thermography (ECPT), a newly developed non-destructive testing (NDT) technique, has advantages such as rapid inspection of a large area within a short time, high spatial resolution, high sensitivity and stand-off measurement distance. This paper investigates ECPT for the evaluation of gear fatigue tests. The paper proposes a statistical method based on single channel blind source separation to extract details of gear fatigue. The discussion of transient thermal distribution and patterns of fatigue contact surfaces as well as the non-contact surfaces have been reported. In addition, the measurement for gears with different cycles of fatigue tests by ECPT and the comparison results between ECPT with magnetic Barkhausen noise (MBN) have been evaluated. The comparison shows the competitive capability of ECPT in fatigue evaluation. [ABSTRACT FROM AUTHOR]
Electrical heating box with multi -loop control has several features as great inertia and coupling. It is a type of multi-variable system. To solve the problem, a kind of decoupling designed implicit generalized predi...
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Electrical heating box with multi -loop control has several features as great inertia and coupling. It is a type of multi-variable system. To solve the problem, a kind of decoupling designed implicit generalized predictive control (IGPC) method is discussed. The Multi-variable IGPC based on decoupling design. Using decentralized objective function and feedforward decoupling, the decoupling IGPC is achieved to control a multi -variable system. According to input and output data, the parameters of optimal control law could be identified through use of Recursive Least Squares (RLS). This method avoids solving Diophantine equations by online. The IGPC is used for control electrical heating box with three multi-loops through simulation study. In the test process, compared with the IGPC effect and traditional PID control effect and analyzed the control effect through changing softness parameter. The test results show that the IGPC could eliminate the coupling between loops and have good control stability.
This paper presents a 3-transistor CMOS active pixel structure with in-pixel correlated double sampling. designed in a standard 0.18 μm CMOS process, the structure effectively suppresses temporal noise and fixed patt...
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This paper presents a 3-transistor CMOS active pixel structure with in-pixel correlated double sampling. designed in a standard 0.18 μm CMOS process, the structure effectively suppresses temporal noise and fixed pattern noise (FPN), thanks to the shared correlated double sampling circuit inside the pixel. Fill factor is also improved while maintaining pixel performance. Validation by Spectre simulator shows that the proposed structure suppresses 100 mV input offset to the microvolt range, and the pixel readout time is ~90 ns. The average power consumption of each pixel is 18 μW.
Avoiding use of traditional high-speed analog-to digital converters (ADCs) and constant fraction discriminators, multi-voltage threshold (MVT) method is able to digitally sample positron emission tomography (PET) scin...
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ISBN:
(纸本)9781467325240
Avoiding use of traditional high-speed analog-to digital converters (ADCs) and constant fraction discriminators, multi-voltage threshold (MVT) method is able to digitally sample positron emission tomography (PET) scintillation pulse with reasonable cost. As the key component of the MVT method, a time-to-digital convertor (TDC) with high resolution and large dynamic range is presented in this work. The TDC architecture uses a delay locked loop (DLL) to generate the fast clock edges from a 100 MHz clock, and a 32-stage Vernier delay lines (VDL) is used to achieve the 40pS timing resolution. The proposed TDC is designed using the standard 0.25 μm CMOS technology with 2.5V normal supply voltage. The power consumption of the TDC is ~70 mW.
In order to consider the effect of battery temperature on the total fuel consumption when a Pontryagin's Minimum Principle (PMP)-based power management strategy is applied to a fuel cell hybrid vehicle (FCHV), thi...
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For traditional piezoelectric energy harvesters, the harvested power is very low in the non-resonant frequency. In order to solve the problem, a new active piezoelectric energy harvester is designed. The electromechan...
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For traditional piezoelectric energy harvesters, the harvested power is very low in the non-resonant frequency. In order to solve the problem, a new active piezoelectric energy harvester is designed. The electromechanical coupling model and the equivalent electrical model of the piezoelectric dynamic system are built. The adaptive active piezoelectric energy harvesting technology is investigated, and an analytical expression of an optimal control voltage harvested the maximum power is derived. Finally, an adaptive active piezoelectric energy harvesting circuit which can achieve this optimal control voltage is proposed. Experimental results reveal that the adaptive active piezoelectric energy harvester can significantly improve harvested power in the broadband. Therefore, it can be used in the energy supply field for the MEMS, WSN and embedded systems.
High angle of attack flows over a 20° conical forebody are computed by the commercial CFD code ANSYS CFX in this paper. The free-stream velocities are 10 to 70 m/s, the Reynolds number based on the forebody base ...
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The advanced pressurized water reactor with a tight hexagonal lattice core design has its potential to improve uranium utilization. With a smaller pitch-to-diameter ratio (p/d) ranging from 1.05 to 1.20, a major probl...
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The method of characteristics based on arbitrary trajectory adopts interpolation method to deal with the reflective boundary, which can break the restriction on the choice of trajectory layouts and quadrature sets. An...
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The relationship between the control system of the nuclear power plant(NPP) and the condition monitoring system which provides support for the operator is very close, but in most nuclear power plant design, these two ...
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The relationship between the control system of the nuclear power plant(NPP) and the condition monitoring system which provides support for the operator is very close, but in most nuclear power plant design, these two systems are designed separately, which affects the system compatibility, the utilization efficiency of the system resources, the extendibility of the systems and the real–time nature of the support, and may have some negative impacts on the plant operation. Focusing on this problem, an integrated design concept for the NPP control system and condition monitoring system is proposed in this paper. The overview scheme of the integrated system is given based on the analysis of the functions required. Furthermore, the study for modeling of the integrated control and condition monitoring system using the IDEF(Integration Definition Language) and UCM(Use Case Maps) methods is introduced in this paper.
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