Plate structures are employed as important structural components in many engineering applications. Hence, assessing the structural conditions of in-service plate structures is critical to monitoring global structural ...Plate structures are employed as important structural components in many engineering applications. Hence, assessing the structural conditions of in-service plate structures is critical to monitoring global structural health. Modal curvature-based damage detection techniques have recently garnered considerable attention from the research community, and have become a promising vibration-based structural health monitoring solution. However, computing errors arise when calculating modal curvatures from lateral mode shapes, which result from unavoidable measurement errors in the mode shapes as identified from lateral vibration signals; this makes curvature-based algorithms that use a lateral measurement only theoretically feasible, but practically infeasible. Therefore, in this study, long-gauge fiber Bragg grating strain sensors are employed to obtain a modal curvature without a numerical differentiation procedure in order to circumvent the computing errors. Several damage indices based on modal curvatures that were developed to locate beam damage are employed. Both numerical and experimental studies are performed to validate the proposed approach. However, although previous studies have reported relative success with the application of these damage indices on a simple beam, only one damage index demonstrated the capability to locate damage when the stiffness of the local region changed near the sensor.展开更多
The wave-aether model was proposed long time ago. We study Michelson interferometer experiment and find that its theoretical calculation erroneously neglected the aether drag effect. We take the drag effect into accou...The wave-aether model was proposed long time ago. We study Michelson interferometer experiment and find that its theoretical calculation erroneously neglected the aether drag effect. We take the drag effect into account and reanalyze the theoretical interference pattern shift. The result is null because the drag coefficient of aether is zero. Such that the wave-aether model fulfills all light propagation characteristics. We design and implement a system to measure the starlight speed by comparing to that from a local source. We observe that the arrival times are different. It implies the apparent speeds of starlights are not equal to c.展开更多
This paper studies the effects of deflection on the SiO2 barrier layer and molybdenum(Mo)back electrode of Cu(In,Ga)Se2 thin-film solar cells,prepared via magnetron sputtering on type SUS431 stainless steel substrates...This paper studies the effects of deflection on the SiO2 barrier layer and molybdenum(Mo)back electrode of Cu(In,Ga)Se2 thin-film solar cells,prepared via magnetron sputtering on type SUS431 stainless steel substrates.The surface micro-cracks and sheet resistance of thin films had been observed and measured for in-situ bend tests.Experimental results show that increasing the thickness of the SiOx barrier has a better property to prevent cracks induced by bending stress.The sheet resistance of a Mo film increases alongside the bending of the curvature radius.The maximum allowed value of the curvature radius of the SiOx barrier layer,molybdenum electrodes,and the thin film CIGS absorbing layer should be 16 mm,20 mm,and 26 mm,respectively.Therefore,the maximum curvature radius limit should be 26 mm or less for CIGS thin-film solar cells prepared via sputtering on type SUS431 stainless steel substrates.展开更多
文摘Plate structures are employed as important structural components in many engineering applications. Hence, assessing the structural conditions of in-service plate structures is critical to monitoring global structural health. Modal curvature-based damage detection techniques have recently garnered considerable attention from the research community, and have become a promising vibration-based structural health monitoring solution. However, computing errors arise when calculating modal curvatures from lateral mode shapes, which result from unavoidable measurement errors in the mode shapes as identified from lateral vibration signals; this makes curvature-based algorithms that use a lateral measurement only theoretically feasible, but practically infeasible. Therefore, in this study, long-gauge fiber Bragg grating strain sensors are employed to obtain a modal curvature without a numerical differentiation procedure in order to circumvent the computing errors. Several damage indices based on modal curvatures that were developed to locate beam damage are employed. Both numerical and experimental studies are performed to validate the proposed approach. However, although previous studies have reported relative success with the application of these damage indices on a simple beam, only one damage index demonstrated the capability to locate damage when the stiffness of the local region changed near the sensor.
文摘The wave-aether model was proposed long time ago. We study Michelson interferometer experiment and find that its theoretical calculation erroneously neglected the aether drag effect. We take the drag effect into account and reanalyze the theoretical interference pattern shift. The result is null because the drag coefficient of aether is zero. Such that the wave-aether model fulfills all light propagation characteristics. We design and implement a system to measure the starlight speed by comparing to that from a local source. We observe that the arrival times are different. It implies the apparent speeds of starlights are not equal to c.
基金supported in part by the Materials and Electro-Optics Research Division,Chung-Shan Institute of Science and Technology and the National Science Council of Taiwan,R.O.C.under contract numbers CSIST-769-V204
文摘This paper studies the effects of deflection on the SiO2 barrier layer and molybdenum(Mo)back electrode of Cu(In,Ga)Se2 thin-film solar cells,prepared via magnetron sputtering on type SUS431 stainless steel substrates.The surface micro-cracks and sheet resistance of thin films had been observed and measured for in-situ bend tests.Experimental results show that increasing the thickness of the SiOx barrier has a better property to prevent cracks induced by bending stress.The sheet resistance of a Mo film increases alongside the bending of the curvature radius.The maximum allowed value of the curvature radius of the SiOx barrier layer,molybdenum electrodes,and the thin film CIGS absorbing layer should be 16 mm,20 mm,and 26 mm,respectively.Therefore,the maximum curvature radius limit should be 26 mm or less for CIGS thin-film solar cells prepared via sputtering on type SUS431 stainless steel substrates.
