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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Summary of Conference     

West  Richard 《Earth, Moon, and Planets》1997,79(1-3):309-319

The recent apparition of comet Hale-Bopp has provided the first opportunity to study a truely “Great Comet” with modern observational equipment, from ground and from space. An enormous amount of data was gathered and is still in the process of being analysed. When compared with elaborate and realistic theoretical considerations, important new insights are now being obtained into the complex physical and chemical processes in the cometary environment. This summary highlights some of the main achievements of this work, as they were presented at the first major international conference on comet Hale-Bopp in February 1998. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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   

High-resolution δ¹³C measurements on ancient air extracted from less than 10 cm³ of ice     

M. C. LEUENBERGER  M. EYER  P. NYFELER  B. STAUFFER  T. F. STOCKER 《Tellus. Series B, Chemical and physical meteorology》2003,55(2):138-144

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The evolution of binary fractions in globular clusters     

N. Ivanova  K. Belczynski  J. M. Fregeau  F. A. Rasio 《Monthly notices of the Royal Astronomical Society》2005,358(2):572-584

We study the evolution of binary stars in globular clusters using a new Monte Carlo approach combining a population synthesis code ( startrack ) and a simple treatment of dynamical interactions in the dense cluster core using a new tool for computing three- and four-body interactions ( fewbody ). We find that the combination of stellar evolution and dynamical interactions (binary–single and binary–binary) leads to a rapid depletion of the binary population in the cluster core. The maximum binary fraction today in the core of a typical dense cluster such as 47 Tuc, assuming an initial binary fraction of 100 per cent, is only ∼ 5–10 per cent. We show that this is in good agreement with recent Hubble Space Telescope observations of close binaries in the core of 47 Tuc, provided that a realistic distribution of binary periods is used to interpret the results. Our findings also have important consequences for the dynamical modelling of globular clusters, suggesting that 'realistic models' should incorporate much larger initial binary fractions than has usually been the case in the past.  相似文献