To understand the formation mechanism of blue stragglers in open clusters, we conducted a photometric analysis for a blue straggler eclipsing binary in the old open cluster NGC 2141. By using the least square fitting ...To understand the formation mechanism of blue stragglers in open clusters, we conducted a photometric analysis for a blue straggler eclipsing binary in the old open cluster NGC 2141. By using the least square fitting of times of minima, we derived the ephemeris and redetermined the orbital period of this system to be 0.6227 d. We have also done a photometric analysis for light curve with the Wilson-Devinney Code （2003）. The photometric solutions reveal a semi-detached binary with the second- ary component filling its Roche lobe. The photometric mass ratio MJMI （secondary/primary） was determined to be 0.190_＋0.002 and the ratio of V-band luminosity L2/LI（V） is about 0.033_＋0.001, which indicates the secondary component is overluminous. Thus, this blue straggler likely results from a substantial mass exchange between these two components.展开更多
We report rigorous coupled-wave analysis(RCWA) method to non-destructively characterize the domain structure of periodically poled lithium niobate(PPLN) crystal. The strong light diffraction effect is achieved by appl...We report rigorous coupled-wave analysis(RCWA) method to non-destructively characterize the domain structure of periodically poled lithium niobate(PPLN) crystal. The strong light diffraction effect is achieved by applying a proper external voltage. We can observe reversed domain pattern and employ the detected diffraction intensity to optimally fit the result of RCWA based on least square method. Compared with conventional scalar diffraction theory, more accurate domain structure parameters with accuracies of 0.05 μm and 0.005 for the period and duty cycle are obtained respectively. It is proved that accurate, real-time and nondestructive characterization can be realized via this method.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11033008 and 11103072)the Chinese Academy of Sciences (Grant No. KJCX2-YW-T24)the National Basic Research Program of China (Grant No. 2009CB824800)
文摘To understand the formation mechanism of blue stragglers in open clusters, we conducted a photometric analysis for a blue straggler eclipsing binary in the old open cluster NGC 2141. By using the least square fitting of times of minima, we derived the ephemeris and redetermined the orbital period of this system to be 0.6227 d. We have also done a photometric analysis for light curve with the Wilson-Devinney Code （2003）. The photometric solutions reveal a semi-detached binary with the second- ary component filling its Roche lobe. The photometric mass ratio MJMI （secondary/primary） was determined to be 0.190_＋0.002 and the ratio of V-band luminosity L2/LI（V） is about 0.033_＋0.001, which indicates the secondary component is overluminous. Thus, this blue straggler likely results from a substantial mass exchange between these two components.
基金supported by the National High Technology Research and Development Program of China(No.2013AA030501)
文摘We report rigorous coupled-wave analysis(RCWA) method to non-destructively characterize the domain structure of periodically poled lithium niobate(PPLN) crystal. The strong light diffraction effect is achieved by applying a proper external voltage. We can observe reversed domain pattern and employ the detected diffraction intensity to optimally fit the result of RCWA based on least square method. Compared with conventional scalar diffraction theory, more accurate domain structure parameters with accuracies of 0.05 μm and 0.005 for the period and duty cycle are obtained respectively. It is proved that accurate, real-time and nondestructive characterization can be realized via this method.
