The long period bright comet C / 1995 O1 (Hale - Bopp) was discovered on July23, 1995 by astronomers A. Hale and T. Bopp. It will pass the perihelion in eariyApril, 1997. We obtained the CCD photometric data of the co...The long period bright comet C / 1995 O1 (Hale - Bopp) was discovered on July23, 1995 by astronomers A. Hale and T. Bopp. It will pass the perihelion in eariyApril, 1997. We obtained the CCD photometric data of the comet from March toDecember, 1996 by using 1.56m telescope of Sheshan Station of Shanghai Observatory.The observational data have been reduced, and according to our data, the orbitalelements and the perturbational ephemeris of the comet have been calculated. In thispaper the processes of reduction and calculation are stated, and the results areanalysed and discussed.展开更多
The long period bright comet C/1995 O1 (Hale-Bopp) was discovered on July 23, 1995 by astronomers A. Hale ahd T. Bopp. It will pass the perihelion in early April, 1997. We obtained the CCD photometric data of the come...The long period bright comet C/1995 O1 (Hale-Bopp) was discovered on July 23, 1995 by astronomers A. Hale ahd T. Bopp. It will pass the perihelion in early April, 1997. We obtained the CCD photometric data of the comet from March to December, 1996 by using 1.56m telescope of Sheshan Station of Shanghai Observatory. The observational data have been reduced, and according to our data, the orbital elements and the perturbational ephemeris of the comet have been calculated. In this paper the processes of reduction and calculation are stated, and the results are analysed and discussed.展开更多
The investigation on the aerodynamic characteristics of the high-attitude long-endurance (HALE) Diamond Joined-Wing configuration unmanned aerial vehicle ( UAV) was carried out by the theoretical analysis method and n...The investigation on the aerodynamic characteristics of the high-attitude long-endurance (HALE) Diamond Joined-Wing configuration unmanned aerial vehicle ( UAV) was carried out by the theoretical analysis method and numerical simulation. Research indicates that as the wing of the UAV is composed of the front wing and the after wing, the after wing has the ability to transmit the front wing's boundary layer to the after wing root which can inhibit the front wing's flow separation. Although the front wing was affected by the retardation of the after wing, the aerodynamic performance of the front wing was better than that of alone front wing in most cases. The after wing was also affected by the wake and downwash of the front wing, and its aerodynamic performance was greatly decreased. The characteristic curve of the pitching moment of the UAV had nonlinear characteristics. The flow field structure of the after wing changed by the front wing wake direct sweep and flow separation at the after wing root were the main reasons that non-linear ′rise′phenomenon occurred in two segments ( α = 0° and α = 8° ) of the characteristic curve of pitching moment. Moreover, coupling of the flow separation characteristic of the front wing and the after wing resulted in the pitching moment ′pitchup′ phenomenon. The lateral-directional static stability of the flat layout was weak. The HALE Diamond Joined-Wing configuration UAV ' s aerodynamic performance can be improved and the problems in engineering applications can be effectively alleviated by adjusting the overall layout parameters.展开更多
The wavelet transform is applied to studying the near nuclear region of Comet Hale Bopp. The transform suppresses the coma background to enhance visibility of coma features such as jets and shells from which apparent ...The wavelet transform is applied to studying the near nuclear region of Comet Hale Bopp. The transform suppresses the coma background to enhance visibility of coma features such as jets and shells from which apparent expansion speed is measured. Furthermore, two cometary bursts of this comet were found on April 22 and Sept. 10 11. 1996. The latter one coincides with a strong increase in the luminosity in X rays almost at the same time. During the outburst, two globular ejecta were found, and their expanding speeds were about 100m/s. In addition, the projected rotation period is derived.展开更多
文摘The long period bright comet C / 1995 O1 (Hale - Bopp) was discovered on July23, 1995 by astronomers A. Hale and T. Bopp. It will pass the perihelion in eariyApril, 1997. We obtained the CCD photometric data of the comet from March toDecember, 1996 by using 1.56m telescope of Sheshan Station of Shanghai Observatory.The observational data have been reduced, and according to our data, the orbitalelements and the perturbational ephemeris of the comet have been calculated. In thispaper the processes of reduction and calculation are stated, and the results areanalysed and discussed.
文摘The long period bright comet C/1995 O1 (Hale-Bopp) was discovered on July 23, 1995 by astronomers A. Hale ahd T. Bopp. It will pass the perihelion in early April, 1997. We obtained the CCD photometric data of the comet from March to December, 1996 by using 1.56m telescope of Sheshan Station of Shanghai Observatory. The observational data have been reduced, and according to our data, the orbital elements and the perturbational ephemeris of the comet have been calculated. In this paper the processes of reduction and calculation are stated, and the results are analysed and discussed.
基金Sponsored by the Civil Aircraft Project(Grant No.MIE-2015-F-009)the Shaanxi Province Science and Technology Project(Grant No.2015KTCQ01-78)
文摘The investigation on the aerodynamic characteristics of the high-attitude long-endurance (HALE) Diamond Joined-Wing configuration unmanned aerial vehicle ( UAV) was carried out by the theoretical analysis method and numerical simulation. Research indicates that as the wing of the UAV is composed of the front wing and the after wing, the after wing has the ability to transmit the front wing's boundary layer to the after wing root which can inhibit the front wing's flow separation. Although the front wing was affected by the retardation of the after wing, the aerodynamic performance of the front wing was better than that of alone front wing in most cases. The after wing was also affected by the wake and downwash of the front wing, and its aerodynamic performance was greatly decreased. The characteristic curve of the pitching moment of the UAV had nonlinear characteristics. The flow field structure of the after wing changed by the front wing wake direct sweep and flow separation at the after wing root were the main reasons that non-linear ′rise′phenomenon occurred in two segments ( α = 0° and α = 8° ) of the characteristic curve of pitching moment. Moreover, coupling of the flow separation characteristic of the front wing and the after wing resulted in the pitching moment ′pitchup′ phenomenon. The lateral-directional static stability of the flat layout was weak. The HALE Diamond Joined-Wing configuration UAV ' s aerodynamic performance can be improved and the problems in engineering applications can be effectively alleviated by adjusting the overall layout parameters.
文摘The wavelet transform is applied to studying the near nuclear region of Comet Hale Bopp. The transform suppresses the coma background to enhance visibility of coma features such as jets and shells from which apparent expansion speed is measured. Furthermore, two cometary bursts of this comet were found on April 22 and Sept. 10 11. 1996. The latter one coincides with a strong increase in the luminosity in X rays almost at the same time. During the outburst, two globular ejecta were found, and their expanding speeds were about 100m/s. In addition, the projected rotation period is derived.
