This note concerns the delay-dependent robust stability analysis for uncertain singular time-delay systems. The parameter uncertainty is assumed to be norm-bounded and possibly time-varying, while the time delay consi...
This note concerns the delay-dependent robust stability analysis for uncertain singular time-delay systems. The parameter uncertainty is assumed to be norm-bounded and possibly time-varying, while the time delay considered here is assumed to be constant but unknown. By using a new Lyapunov-krasovskii functional which splits the whole delay interval into two subintervals and defines a different energy function on each subinterval, some delay-dependent conditions are presented for the singular time-delay system to be regular, impulse free and robustly stable. The obtained delay-dependent criteria are effective and less conservative than previous ones, which are illustrated by numerical examples.
Electromagnetic tomography (EMT) is a kind of electric tomography in combining with electromagnetic induction principles and computerized tomography. It is widely studied and applied in biomedical and industrial area ...
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Electromagnetic tomography (EMT) is a kind of electric tomography in combining with electromagnetic induction principles and computerized tomography. It is widely studied and applied in biomedical and industrial area recently. EMT sensor has advantages of non-invasion, non-contact and non-hazard. The paper aims to work on design of EMT sensor on double-frequency excitation EMT sensor adopts eight coils distributed homogenously out of measuring pipe. The sensing field model is set up based on electromagnetic induction principle and the simulation is practiced in COMSOL Multiphysics. The relation between position information, conductivity and permeability of object and measurement electric potential are presented and analyzed in the paper. The diameters of screen and coils are simulated in the paper. Simulative Result of EMT sensor describes the relation map of between sensing field and measurement voltage and provides useful prior information for design of EMT system.
Electrical resistance tomography (ERT) is a kind of process Tomography (PT) which is based on the theory of electromagnetic fields and the principle of electrical sensitivity. It has an extensive application prospect ...
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The optimized control of combustion engines with regard to minimized fuel consumption and emissions requires nonlinear models. Because of an increase of control inputs, like fuel mass flow, injection angle, exhaust ga...
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The method and computer-aided tool described in this article can be used for the rapid assessment and bench-marking of automation systems, their performance and related working procedures. Potential for improvement ca...
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The method and computer-aided tool described in this article can be used for the rapid assessment and bench-marking of automation systems, their performance and related working procedures. Potential for improvement can be identified and its economic impact estimated. This new method has helped customers to identify the most relevant issues in several pilot studies.
Microstructure, hardness and mechanical properties of the ICr5Mo steel tubes for the coking furnace at super temperature were investigated in this paper. It revealed that under super-temperature, oxidation corrosion f...
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Microstructure, hardness and mechanical properties of the ICr5Mo steel tubes for the coking furnace at super temperature were investigated in this paper. It revealed that under super-temperature, oxidation corrosion for the furnace tubes was strengthened, wall thickness was evident thinner, pearlite in microstructure was spheroidised mostly, strength would be decreased and marked degradation in material occurred.
Electromagnetic Tomography (EMT) which combined electromagnetic theory and computerized tomography technology is one of the electrical tomography technologies. This technology can reconstruct the spatiotemporal distri...
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In the present work, the mechanical properties of 321 stainless steel pressure equipments exposed to an accident fire in a chemical unit were investigated. The performance and microstructure of this material were desc...
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In the present work, the mechanical properties of 321 stainless steel pressure equipments exposed to an accident fire in a chemical unit were investigated. The performance and microstructure of this material were described by chemical compositions analysis, tensile test, scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The experiment results showed that the mechanical properties of the material were degraded. The grains on the external surface of the fracture became coarse. These results indicated that serious damage to 321 stainless steel had been induced by extreme heat of the fire and this pressure vessel could not be used anymore.
Fatigue crack growth rate for 16MnR steel was simulated based on a damage model, which is assessed with local stress and strain near the crack tip. The cyclic elastic-plastic stress-strain field near the crack tip is ...
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Fatigue crack growth rate for 16MnR steel was simulated based on a damage model, which is assessed with local stress and strain near the crack tip. The cyclic elastic-plastic stress-strain field near the crack tip is analyzed using the finite element method. Two sets of programs were developed to recall stress-strain responses and to calculate crack tip damage and crack growth rate. CT specimen fatigue crack growth experiments of 16MnR steel with two R-ratios were conducted at room temperature. Comparison of FE simulation and experiment results shows that the current simulation of crack growth based on the fatigue damage criterion is accordant with the results of the experiment.
Fatigue crack growth behavior of 16MnR steel was experimentally studied using compact specimens subjected to different R-ratios and overloading. The effects of different notch sizes ranging from very sharp to blunt we...
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Fatigue crack growth behavior of 16MnR steel was experimentally studied using compact specimens subjected to different R-ratios and overloading. The effects of different notch sizes ranging from very sharp to blunt were also investigated. The experimental results show that stable crack growth rate follows the Paris law and the R-ratio has an insignificant influence. A larger notch results in a larger deviation of the crack growth curve prior to stabilization. In addition, the influences of overload were studied particularly by applying one single overload after the crack growth rate reached the stable state. The results reveal that the crack growth rate was enhanced right after the application of the overload followed by a rapid decrease. And then the crack growth rate started to increase slowly and merged the stable crack growth curve eventually.
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