Simulations of multimode bolometric interferometers     

George Saklatvala  Michael P. Hobson  Stafford Withington 《Monthly notices of the Royal Astronomical Society》2006,367(3):1194-1200

We describe a procedure for the numerical modelling of astronomical interferometers, with particular relevance to far-infrared and submillimetre wavelengths. The scheme is based on identifying a set of modes that carry power from the sky to the detector. The procedure is extremely general, and can be used to model scalar or vector fields, in any state of coherence and polarization, the only limitation being that the propagation of a coherent field through the system be described by an integral transform, a constraint that is in practise always met.
We present simulations of ideal, multimode two-dimensional interferometers, and show that the modal theory reproduces the correct behaviour of both Michelson and Fizeau interferometers. We calculate simulated visibility data for a multimode bolometric Michelson interferometer, with a synthesized source, and produce a dirty map, recovering the original source with the usual artefacts associated with interferometers.  相似文献   

Surface brightness profiles and structural parameters for 53 rich stellar clusters in the Large Magellanic Cloud     

A. D. Mackey  G. F. Gilmore 《Monthly notices of the Royal Astronomical Society》2003,338(1):85-119

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Chandrasekhar's perturbation method-oriented theories up to third order for uniformly and differentially-rotating polytropic stars: Error-removing techniques     

V. S. Geroyannis  F. N. Valvi 《Astrophysics and Space Science》1986,126(1):119-132

In this paper we analyse error-removing techniques used without sufficient theoretical support in a previous paper, where Chandrasekhar's higher-order perturbation theories were developed for either uniformly or differentially-rotating polytropic stars.  相似文献   

Nitric acid vapour measurements in the troposphere and lower stratosphere by chemical ionisation mass spectrometry     

G. Knop  F. Arnold 《Planetary and Space Science》1985,33(8):983-986

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Quantitative methods in the earth sciences     

A. F?rster  D. F. Merriarn 《Mathematical Geology》1997,29(5):727

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Finite-element analysis of time-dependent large-deformation problems     

Manoj B. Chopra  Gary F. Dargush 《国际地质力学数值与分析法杂志》1992,16(2):101-130

An updated Lagrangian finite-element formulation has been developed for time-dependent problems of soil consolidation involving finite deformations. Large plastic strains as well as rotations occur in such problems and nominal stress measures are introduced in the formulation to redefine stresses. This leads to corrective terms for equilibrium and yield violations in addition to geometric stiffening terms in the governing integral equations. The soil is considered to be either a linear elastic or an elastoplastic, critical-state material. Some simple numerical examples are studied to validate the formulation, followed by a detailed analysis of the problem of penetration of a pile into soil. The results of this problem are viewed with emphasis on the physical interpretation and practical significance.  相似文献   

Evaluation of the impacts of major management changes in the Atlantic salmon (Salmo salar L.) fisheries of Newfoundland and Labrador, Canada, 1984-1988     

O'Connell  M. F.; Dempson  J. B.; Reddin  D. G. 《ICES Journal of Marine Science》1992,49(1):69-87

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Black sea environment     

Alexander V. Drozdov  Anatoly F. Mandych 《GeoJournal》1992,27(2):139-139

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Relationships Between Saline Ground Water Soil, and Leaf Tissue Composition of the Phreatophyte Mezquite     

F. L. García-Carreño  E. Troyo-Diéguez  J. L. Ochoa 《Ground water》1992,30(5):676-682

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Environmental effects on galaxy luminosity functions: the cluster Abell 496     

F. Durret  C. Adami  C. Lobo 《Astrophysics and Space Science》2003,285(1):185-189

We have derived the galaxy luminosity function in various regions of the cluster of galaxies Abell 496 from a wide field image in the I band. A Schechter function fit in the 17≤ I_AB ≤22(–19.5≤ M_IAB ≤ –14.5) magnitude interval gives a steep power law index, which is somewhat steeper in the outer regions than in the inner zones. This result agrees with previous findings obtained by several teams on the Coma cluster and can be interpreted as due to the fact that faint galaxies are accreted by large ones in the central regions. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献