Investigation of the galaxy Markaryan 306     

A. R. Petrosyan  M. Turatto  É. E. Khachikyan 《Astrophysics》1986,24(1):1-8

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Observation and preliminary analysis of a recent Jovian satellite phenomenon     

Allen  W. H.  Budding  E. 《Earth, Moon, and Planets》1986,35(1):73-77

The occultation of Io by Ganymede as observed on 10 June 1985 is reported. The middle of the occultation minimum was found to occur at 14h 14m 5.7s UT. In the plane perpendicular to the line of sight the centres of the two satellite disks passed to within ~ 2530 km of each other, at a relative velocity, in this plane, of about 11 kms^–1. The values of these last two quantities, however, depend on what assumptions are made about the light distribution over io's disk.  相似文献   

Optical manifestations of superluminal expansion of components belonging to the millisecond radio structure in the quasar 3C 345     

M. K. Babadzhanyants  E. T. Belokon' 《Astrophysics》1985,23(3):639-646

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A neural network approach to ship track-keeping control     

Yao Zhang Hearn  G.E. Sen  P. 《Oceanic Engineering, IEEE Journal of》1996,21(4):513-527

This paper presents an on-line trained neural net work controller for ship track-keeping problems. Following a brief review of the ship track-keeping control development since the 1980's, an analysis of various existing backpropagation-based neural controllers is provided. We then propose a single-input multioutput (SIMO) neural control strategy for situations where the exact mathematical dynamics of the ship are not available. The aim of this study is to build an autonomous neural controller which uses rudder to regulate both the tracking error and heading error. During the whole control process, the proposed SIMO neural controller adapts itself on-line from a direct evaluation of the control accuracy, and hence the need for a “teacher” or an off-line training process can be removed. With a relatively modest amount of quantitative knowledge of the ship behavior, the design philosophy enables real time control of a nonlinear ship model under random wind disturbances and measurement noise. Three different track-keeping tasks have been simulated to demonstrate the effectiveness of the training method and the robust performance of the proposed neural control strategy  相似文献   

Geothermal palaeogradients and metamorphic zonation from the conodont colour alteration index (CAI)     

Susana García-López  Fernando Bastida  Jesús Aller  & Javier Sanz-López 《地学学报》2001,13(2):79-83

The conodont colour alteration index (CAI) is potentially valuable in thermal history investigations, but there are problems in its use. An approach is proposed herein to overcome the problem of establishing reliable geothermal palaeogradients in areas with burial metamorphism, based on knowledge of the stratigraphic succession thickness, the boundaries of chronostratigraphic units, and the age and duration of deformation episodes. Although also problematical that a correlation between CAI and Kübler index (KI) values does not exist, there are areas where CAI and KI values are notably consistent for the anchizone boundaries; however, anomalous correlations between CAI and KI values have also been found in some areas. A CAI anchizone (or ancaizone) is defined in order to enable CAI values to be used independently to establish a metamorphic zonation.  相似文献   

Dynamical transport to planet crossing orbits     

Christiane Froeschlé 《Celestial Mechanics and Dynamical Astronomy》1996,65(1-2):165-173

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Longitudinal dispersion compensation for the Very Large Telescope Interferometer     

Samuel Lévêque  Bertrand Koehler  Oskar von der Lühe 《Astrophysics and Space Science》1996,239(2):305-314

The Very Large Telescope Interferometer [1,13] will be operated in air which will introduce small optical path fluctuations due to internal turbulence [4,6] and dispersion effects. Both may contribute to fringe contrast decrease. Longitudinal dispersion effects can be corrected by inserting an appropriate glass of variable thickness in one arm of the interferometer [3,5,11,12]. This paper presents a new method applied to VLTI in order to select the optimum glass, according to both the observing wavelength and the spectral bandpath, and to calculate its thickness. Results are presented in terms of improvement on the fringe contrast.  相似文献   

Solar-planetary cycles in Jupiter's great red spot darkness     

I. Liritzis  B. Petropoulos  C. Banos  E. Sarris 《Earth, Moon, and Planets》1996,73(2):167-179

The change in the darkness of the Great Red Spot (GRS) of Jupiter (1894–1974) has been analysed with Fourier (FFT), Maximum Entropy and Power spectrum (Blackman-Tukey window) (PSA) methods of spectrum analysis. Significance, non-randomness and stationarity tests assigned high variance to periodicities of 33 ± 4, 13–15, about 11, 9 and 3 yrs. The highest correlation between solar activity and GRS darkness was found for the 14th and 16th solar cycle. The periodicities obtained are interpreted as the combined eftects of solar activity, planetary resonances and internal jovian mechanisms.  相似文献   

Brief description of bare essentials of surface transfer and results from simulations with the HAPEX-MOBILHY data     

A. J. Pitman  C. E. Desborough 《Global and Planetary Change》1996,13(1-4)

The Bare Essentials of Surface Transfer (BEST) land surface scheme is briefly described and the key physical parameterisations discussed. Results are then presented to illustrate how the model performs, with forcing data for HAPEX-MOBILHY, compared to a series of other schemes in the simulation of evaporation and sensible heat. The implications of the models performance, and some indications of the future development of the scheme are provided. The basic version of BEST was found to overestimate evaporation for the HAPEX-MOBILHY data, simulating 816 mm yr⁻¹ compared to a range of 550 to 816 mm yr⁻¹ for all models. A modification to the β parameterisation reduced the evaporation to 759 mm yr⁻¹ which, although an improvement, is still probably too high.  相似文献   

A deep Chandra survey of the Groth Strip – I. The X-ray data     

K. Nandra  E. S. Laird  K. Adelberger  Jonathan P. Gardner  R. F. Mushotzky  J. Rhodes  C. C. Steidel  H. I. Teplitz  K. A. Arnaud 《Monthly notices of the Royal Astronomical Society》2005,356(2):568-586

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