The north-south distribution of major solar flare events,sunspot magnetic classes and sunspot areas (1955–1974)     

Roy  J. -René 《Solar physics》1977,52(1):53-61

The north-south incidence has been studied of 31 white-light flares observed since 1859 and of 1669 events meeting the criteria for major flares of Dodson and Hedeman (1971) for the period 1955–1974. The asymmetry in favor of the northern hemisphere increases strikingly with the importance of the events. Similarly, magnetically complex sunspot groups (Mt. Wilson classes, and) display a more pronounced asymmetry in favor of the north than non-complex groups for 1962–1970. Contrary to the flare asymmetry, the spottedness asymmetry is independent of the size of sunspots.  相似文献   

Thermoluminescence of the lunar surface     

Marie-Lise Chanin  Véronique Lepine  Jacques E. Blamont 《Earth, Moon, and Planets》1982,27(2):143-163

Observations of the lunar luminescence are reported for a dozen of specific Moon features using the line-depth method with a high resolution spectroscopic technique. The data indicate a variation of the Moon proper emission as a function of the phase angle which is interpreted as a proof of the thermoluminescent origin of this emission.  相似文献   

Window technique for climate trend analysis     

Tamás Szentimrey  Tibor Faragó  Sándor Szalai 《Climate Dynamics》1992,6(3-4):127-134

Climatic characteristics are affected by various systematic and occasional impacts: besides the changes in the observing system (locations of the stations of the meteorological network, instruments, observing procedures), the possible local-scale and global natural and antropogenic impacts on climatic conditions should be taken into account. Apart from the predictability problems, the phenomenological analysis of the climatic variability and the determination of past persistent climatic anomalies are significant problems, among other aspects, as evidence of the possible anomalous behavior of climate or for climate impact studies. In this paper, a special technique for the identification of such shifts in the observational series is presented. The existence of these significant shorter or longer term changes in the mean characteristics for the properly selected adjoining periods of time is the necessary condition for the formation of any more or less unidirectional climatic trends. Actually, the window technique is based on a complete set of orthogonal functions. The sensitivity of the proposed model on its main parameters is also investigated. This method is applied for hemispheric and Hungarian data series of the mean annual surface temperature.Contribution to Clima Locarno — Past and Present Climate Dynamics; Conference September 1990, Swiss Academy of Sciences — National Climate Program  相似文献   

Les gisements d'or des tonalites archéennes (Abitibi,Québec)     

M. Jébrak 《Mineralium Deposita》1992,27(1):1-9

Résumé De nombreux gisements ont été mis en exploitation depuis une dizaine d'années dans des plutons granitiques de la ceinture de roches vertes archéennes de l'Abitibi. La plupart d'entre eux sont encaissés par des faciès sodiques. Dans la zone sud-est de cette ceintúre, il existe deux types de concentrations, des zones filoniennes et des disséminations à caractère porphyrique.Les gisements filoniens sont encaissés dans des sills ou des dykes de tonalite-trondhjemite. Deux associations minéralogiques sont distinguées, l'une avec tourmaline et scheelite, l'autre avec hématite et métaux de base, spécifiques de chacun des blocs lithotectoniques qui composent la ceinture. Les variations paragénétiques peuvent être mise en relation avec la profondeur de mise en place des systèmes hydrothermaux. A l'échelle d'un bloc, on observe des variations de la structure des minéralisations controlées par les variations de la pression de fluide, plus importante au coeur des massifs et conduisant à des structures plus régulières empruntant des zones de faiblesse préexistantes.Les disséminations sont associées à un granite tardif issu de la refusion de tonalites. Dans la région de Launay, près d'Amos, l'or est associé à des zones d'épisyénites avec pyrite et molybdénite, ou avec des zones de cisaillement. Elles pourraient correspondre à des concentrations plus précoces.

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Several deposits have been developped since 10 years in granitics plutons of the Archean greenstone belt of Abitibi. Most of them are hosted by Na-rich granitoids. In the south-eastern part of Abitibi, two main type of deposit may be distinguished:The lode type is hosted in pre-tectonic dykes or sills of tonalite-trondhjemite. Two mineralogical association are caracterised, one with tourmaline, scheelite, the other with hematite, and seems specific of lithotectonic blocs. Paragenetic variations may be related to vertical variations of deposition. On a bloc scale, high fluid pressure predominate in the center of pluton and may be responsible for more regular structure.The disseminated type is hosted in late granodioritic intrusions associated with tonalite. The only occurrence of that type is the Launay deposit, near Amos. Gold is associated either with abite-rich episyenite, with pyrite and Mo, or with shear-zone cross-cutting the granitic intrusions.

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Synchronous aperture synthesis observations of pulsars     

R. G. Strom  H. W. Van Someren Gréve 《Astrophysics and Space Science》1990,171(1-2):351-355

By modifying the online software of the Westerbork Synthesis Radio Telescope it is possible to sample the radio emission from a field containing a pulsar synchronously with the pulsed signal. Recording the emission from eight separate temporal windows, we can simultaneously observe both the on-pulse and off-pulse signals. We are using this technique for three different kinds of pulsar investigation: (a) to check and improve the positions of some pulsars; (b) to look for unpulsed components; and (c) to search for weak extended emission around pulsars. Observations have been carried out at 6, 21, 49, and 92 cm. Examples of results from all three types of investigation are given.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

Photometry of AR Lac     

M. J. Arévalo  C. Lázaro 《Astrophysics and Space Science》1990,169(1-2):255-256

Visible photometry of the RS CVn system AR Lac is presented. We find some interesting features in the light curves. Also a possible oscillation with period 1.05 hr arises from the data. A new determination of the geometrical parameters of the system is given.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

Periodic orbits of an electric charge in a magnetic dipole field     

Lidia Jiménez-Lara  Eduardo Piña 《Celestial Mechanics and Dynamical Astronomy》1990,49(4):327-345

Periodic orbits in the Stormer problem are studied using the symmetry lines of the Poincaré map introduced by De Vogelaere. Many known facts are explained by mean of these lines. The dynamics of four special symmetry lines when the Stormer parameter ₁ changes is presented, and we obtain a clear global view of the structure of the simple periodic orbits and their bifurcations, including the asymmetrical ones. New asymmetrical multiple periodic orbits are obtained.  相似文献   

Investigation of the electrostatic charging of dust particles in a Paul-trap     

S. Pintér  J. Švestka  E. Grün 《Astrophysics and Space Science》1990,171(1-2):217-218

Dust particles (glass, tungsten, and nickel) with sizes ranging from 0.25 to 3m were levitated in a Paul-trap and charged by ions or electrons. For ions the particle potential is limited at field strength of about 1×10⁹ V m^–1 by a temperature-dependent discharge mechanism. The particles interaction with 2 to 20 keV electrons always leads to positive surface potentials which can be explained in terms of a decreased absorption of electrons by small particles. Micrometer sized agglomerates were used for the investigation of the electrostatic fragmentation. Fragmentation takes place in a twofold manner: small surface flufl can be removed or the parent particle can be disrupted into smaller agglomerates.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

Eta carinae nebulosities in 1963     

Carlos Donzelli  J. L. Sérsic  Adela Abraham 《Astrophysics and Space Science》1990,174(2):285-289

The purpose of this note is to give further information regarding the positions of some condensations around Carinae in 1963, an epoch not yet considered in the literature. The new information is unable to confirm the deceleration hypothesis of theeir motion.  相似文献   

Study of the influence of katabatic flows on the Antarctic circulation using GCM simulations     

P. Pettré  M. F. Renaud  R. Renaud  M. Déqué  S. Planton  J. C. André 《Meteorology and Atmospheric Physics》1990,43(1-4):187-195

Summary A one dimensional analytical model of katabatic wind over the Antarctica has been developed. This parametric model is derived from the bulk two-layer model of Ball including the surface friction and taking into account the Earth's rotation and the geostrophic wind in the upper layer.This model is validated using the data set (70 soundings) collected during IAGO experiment at D47 (67°24S, 138°43E, altitude 1 564m), 110 km inland from the coast of Adélie Land.The parameteric model is then introduced into a GCM which is a spectral global version of the operational numerical weather prediction model used by the French weather service. The most significant effect of the parameterization is a 50 m increase of the geopotential height over the South Pole. The surface temperature at the South Pole increases (2°C) reducing the pole-midlatitude thermal gradient. The westerly circulation at 50° S is slowed down (4m/s at 850 hPa), and the surface pressure at the South Pole increases (4hPa). These results, consistent with an increase of katabatic winds, would however be improved by a better coupling between the parameterization and the GCM boundary layer.With 8 Figures  相似文献