In cooling process of Fe-Cr-Al alloy oxidized at 1 300 ℃, the effect of cooling speed and exposure time on oxide spalled area fraction and successive variety of the spalled region were studied by investigating evolve...In cooling process of Fe-Cr-Al alloy oxidized at 1 300 ℃, the effect of cooling speed and exposure time on oxide spalled area fraction and successive variety of the spalled region were studied by investigating evolvement of the thermally grown oxide using in-situ CCD monitoring technique. The results showed that oxide spallation can be restrained by controlling cooling speed and the critical temperature drop of spallation initiation which is closely related to the oxide thickness or exposure time, and the spallation process of a little region may be described in more detail as two routes： from the oxide/substrate interface micro-decohesion, micro-buckles, buckle spreading, buckle crack to spallation and from the interface micro-decohesion, micro-buckles, buckle crack and spallation to the residual oxide decohesion and spallation.展开更多
We describe a new BVRI multicolor CCD photometric system situated at the prime focus of the 85-cm telescope at the Xinglong Station of NAOC. Atmospheric extinction effects, photometric accuracy and color calibration d...We describe a new BVRI multicolor CCD photometric system situated at the prime focus of the 85-cm telescope at the Xinglong Station of NAOC. Atmospheric extinction effects, photometric accuracy and color calibration dependence of the system are investigated. Additional attention was paid to giving observers guidance in estimating throughput, detection limit, signal-to-noise ratio and exposure time.展开更多
There is a scale error, i.e., a systematic dm which is a function of magnitude, in the CCD photometry of NGC 7790, NGC 4147 and NGC 7006 published by Odewahn et al. The scale error also exists in the CCD photometry of...There is a scale error, i.e., a systematic dm which is a function of magnitude, in the CCD photometry of NGC 7790, NGC 4147 and NGC 7006 published by Odewahn et al. The scale error also exists in the CCD photometry of NGC 7790 by Petrov et al. The reason why this kind of error, which may only exist in photographic photometry, appears in a linear detector such as a CCD, is not immediately clear. If the CCD systems used by Odewahn et al. and Petrov et al. are really linear, maybe it is related to their use of the variable aperture technique in the former and the reduction method in the latter.展开更多
A novel feature-round-based coplanar drone for the CCD camera auto-calibration is designed. Based on the ellipse similarity, an ellipse recognition algorithm is proposed. The experiment indicates the calibration error...A novel feature-round-based coplanar drone for the CCD camera auto-calibration is designed. Based on the ellipse similarity, an ellipse recognition algorithm is proposed. The experiment indicates the calibration error is less than 0.4 pixel.展开更多
基金Item Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars
文摘In cooling process of Fe-Cr-Al alloy oxidized at 1 300 ℃, the effect of cooling speed and exposure time on oxide spalled area fraction and successive variety of the spalled region were studied by investigating evolvement of the thermally grown oxide using in-situ CCD monitoring technique. The results showed that oxide spallation can be restrained by controlling cooling speed and the critical temperature drop of spallation initiation which is closely related to the oxide thickness or exposure time, and the spallation process of a little region may be described in more detail as two routes： from the oxide/substrate interface micro-decohesion, micro-buckles, buckle spreading, buckle crack to spallation and from the interface micro-decohesion, micro-buckles, buckle crack and spallation to the residual oxide decohesion and spallation.
基金Supported by the National Natural Science Foundation of China.
文摘We describe a new BVRI multicolor CCD photometric system situated at the prime focus of the 85-cm telescope at the Xinglong Station of NAOC. Atmospheric extinction effects, photometric accuracy and color calibration dependence of the system are investigated. Additional attention was paid to giving observers guidance in estimating throughput, detection limit, signal-to-noise ratio and exposure time.
基金Supported by the United Laboratory of Optical Astronomy,CAS and a grant from the "Climb Project"
文摘There is a scale error, i.e., a systematic dm which is a function of magnitude, in the CCD photometry of NGC 7790, NGC 4147 and NGC 7006 published by Odewahn et al. The scale error also exists in the CCD photometry of NGC 7790 by Petrov et al. The reason why this kind of error, which may only exist in photographic photometry, appears in a linear detector such as a CCD, is not immediately clear. If the CCD systems used by Odewahn et al. and Petrov et al. are really linear, maybe it is related to their use of the variable aperture technique in the former and the reduction method in the latter.
文摘A novel feature-round-based coplanar drone for the CCD camera auto-calibration is designed. Based on the ellipse similarity, an ellipse recognition algorithm is proposed. The experiment indicates the calibration error is less than 0.4 pixel.
