The airlines need to select the optional equipment according to their individual development demands and the manufacture′s standard specification manual when purchasing a new airplane.For this customization process,t...The airlines need to select the optional equipment according to their individual development demands and the manufacture′s standard specification manual when purchasing a new airplane.For this customization process,the selection theory is mainly based on qualitative analysis and quantitative analysis.The grey incidence analysis(GIA)is used for modeling,which evaluates the correlations between optional equipment and airlines′individual demands.Meanwhile,the customization demands are quantitatively processed as different weights in evaluation index system with analytical hierarchy process.Then,the value of grey incidence degree is obtained which shows whether the optional equipment is on the purchasing list or not.Finally,two airlines′customization demands are applied in the example of aircraft cabin′s seats,so two different purchasing priorities and equipment installation lists can be obtained.The results and comparisons verify the reasonable of modeling,which provides an objective scheme of aircraft equipment selection.展开更多
The post-1994 observations of the blazar OQ 530 in optical BVRI bands, and radio observations at 22 GHz and 37 GHz were collected. The date compensated discrete Fourier transform （DCDFr） and CLEANest methods were us...The post-1994 observations of the blazar OQ 530 in optical BVRI bands, and radio observations at 22 GHz and 37 GHz were collected. The date compensated discrete Fourier transform （DCDFr） and CLEANest methods were used to search for possible periodicities. Two possible periods of 456±100 days and 258±29 days were found in the optical bands. The existence of possible correlations between the optical and radio emissions was investigated by means of discrete correlation function （DCF） analysis, and no significant correlation was found. Some possible mechanisms for the periodic variability are discussed.展开更多
The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of sta...The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of standard stars for flux calibration, we use the photometric data of 15 intermediate bands in the Beijing-Arizona-Taipei-Connecticut （BATC） survey to calibrate the spectra. In to- tal, 59 spectra located in the bulge and disk of the galaxy are obtained. Kinematic and stellar population properties of the stellar content are derived with these spectra. We obtain the global velocity field and calculate corresponding rotation velocities out to about 7 kpc along the major axis. These rotation velocity measurements comple- ment those of the gas content, such as the H I and CO. The radial velocity dispersion shows that the stars in the bulge are more dynamically thermal and the disk is more rotationally-supported. The age distribution shows that the bulge was formed about 12 Gyr ago, the disk is relatively younger and the ages of some regions along the spi- ral arms can reach as young as about 1 Gyr. These young stellar populations have a relatively richer abundance and larger reddening. The overall average metallicity of the galaxy approximates the solar metallicity and a very weak abundance gradient is gained. The reddening map gives a picture of a dust-free bulge and a distinct dusty ring in the disk.展开更多
We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary. The observation covered the optical secondary eclipse and captured an X-r...We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary. The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star. The XMM-Newton European Photon Imaging Camera and Reflection Grating Spectrometer spectra of Algol in its quiescent state are described by a two-temperature plasma model. The cool component has a temperature around 6.4× 106 K while that of the hot component ranges from 2 to 4.0× 107 K. Coronal abundances of C, N, O, Ne, Mg, Si and Fe were obtained for each component for both the quiescent and the flare phases, generally with upper limits for S and Ar, and upper limits for C, N, and O from the hot component. F-tests show that the abundances do not need to be different between the cool and the hot component and between the quiescent and the flare phase with the exception of Fe. Although the Fe abundance of the cool component remains constant at -0.14, the hot component shows an Fe abundance of -0.28, which increases to -0.44 during the flare. This increase is expected from the chromospheric evaporation model. The absorbing column density NH of the quiescent emission is 2.5 - 1020 cm-2, while that of the flare-only emission is significantly lower and consistent with the column density of the interstellar medium. This observation substantiates earlier suggestions of the presence of X-ray absorbing material in the Algol system.展开更多
文摘The airlines need to select the optional equipment according to their individual development demands and the manufacture′s standard specification manual when purchasing a new airplane.For this customization process,the selection theory is mainly based on qualitative analysis and quantitative analysis.The grey incidence analysis(GIA)is used for modeling,which evaluates the correlations between optional equipment and airlines′individual demands.Meanwhile,the customization demands are quantitatively processed as different weights in evaluation index system with analytical hierarchy process.Then,the value of grey incidence degree is obtained which shows whether the optional equipment is on the purchasing list or not.Finally,two airlines′customization demands are applied in the example of aircraft cabin′s seats,so two different purchasing priorities and equipment installation lists can be obtained.The results and comparisons verify the reasonable of modeling,which provides an objective scheme of aircraft equipment selection.
基金the National Natural Science Foundation of China
文摘The post-1994 observations of the blazar OQ 530 in optical BVRI bands, and radio observations at 22 GHz and 37 GHz were collected. The date compensated discrete Fourier transform （DCDFr） and CLEANest methods were used to search for possible periodicities. Two possible periods of 456±100 days and 258±29 days were found in the optical bands. The existence of possible correlations between the optical and radio emissions was investigated by means of discrete correlation function （DCF） analysis, and no significant correlation was found. Some possible mechanisms for the periodic variability are discussed.
基金supported by the National Natural Science Foundation of China (GrantNos. 10873016,10633020,10603006,10803007,10903011,11003021 and 11073032)by the National Basic Research Program of China (973 Program Nos. 2007CB815403,2010CB833004 and 2009CB82480X)
文摘The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of standard stars for flux calibration, we use the photometric data of 15 intermediate bands in the Beijing-Arizona-Taipei-Connecticut （BATC） survey to calibrate the spectra. In to- tal, 59 spectra located in the bulge and disk of the galaxy are obtained. Kinematic and stellar population properties of the stellar content are derived with these spectra. We obtain the global velocity field and calculate corresponding rotation velocities out to about 7 kpc along the major axis. These rotation velocity measurements comple- ment those of the gas content, such as the H I and CO. The radial velocity dispersion shows that the stars in the bulge are more dynamically thermal and the disk is more rotationally-supported. The age distribution shows that the bulge was formed about 12 Gyr ago, the disk is relatively younger and the ages of some regions along the spi- ral arms can reach as young as about 1 Gyr. These young stellar populations have a relatively richer abundance and larger reddening. The overall average metallicity of the galaxy approximates the solar metallicity and a very weak abundance gradient is gained. The reddening map gives a picture of a dust-free bulge and a distinct dusty ring in the disk.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10903007, 10778716and 10878012)
文摘We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary. The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star. The XMM-Newton European Photon Imaging Camera and Reflection Grating Spectrometer spectra of Algol in its quiescent state are described by a two-temperature plasma model. The cool component has a temperature around 6.4× 106 K while that of the hot component ranges from 2 to 4.0× 107 K. Coronal abundances of C, N, O, Ne, Mg, Si and Fe were obtained for each component for both the quiescent and the flare phases, generally with upper limits for S and Ar, and upper limits for C, N, and O from the hot component. F-tests show that the abundances do not need to be different between the cool and the hot component and between the quiescent and the flare phase with the exception of Fe. Although the Fe abundance of the cool component remains constant at -0.14, the hot component shows an Fe abundance of -0.28, which increases to -0.44 during the flare. This increase is expected from the chromospheric evaporation model. The absorbing column density NH of the quiescent emission is 2.5 - 1020 cm-2, while that of the flare-only emission is significantly lower and consistent with the column density of the interstellar medium. This observation substantiates earlier suggestions of the presence of X-ray absorbing material in the Algol system.
