A generalization of Szebehely's equation for three dimensions     

Bálint Érdi 《Celestial Mechanics and Dynamical Astronomy》1982,28(1-2):209-218

Szebehely's equation for the potential generating a prescribed family of orbits in two dimensions is generalized for three-dimensional orbits. A simultaneous system of first-order linear partial differential equations is derived for the determination of the potential in the three-dimensional case. Solutions of this system are found in several cases including Kepler's problem too.Paper presented at the 1981 Oberwolfach Conference on Mathematical Methods in Celestial Mechanics.This paper is dedicated to Professor Victor Szebehely on the occasion of his 60th birthday.  相似文献   

The Earth-Moon tidal force function     

M. Burša 《Earth, Moon, and Planets》1983,28(1):49-53

The concept “the tidal force function of the Earth-Moon system” is introduced and its exact determination based on the Stokes constants (harmonic coefficients) in the external gravitational potential of both bodies is outlined. The exact determination of the torque due to the Moon exerted on the Earth may be performed in terms of the Stokes constants of both bodies and the mutual position of both ellipsoids of inertia.  相似文献   

Longitudinal distribution of PCA sources on the sun     

L. Fritzová-Svestková  Z. Švestka 《Solar physics》1971,17(1):212-217

For 181 PCA's recorded during the years 1956–1969 the association with flares is studied. Both the number of events which cannot be associated with any flare on the visible hemisphere, as well as the longitude distribution of identified proton flares, lead to the conclusion that 25–30% of PCA's are caused by flares behind the western solar limb. PCA's of this kind are mostly small. During the investigated years no PCA > 13 dB and possibly no PCA > 8.5 dB were caused by flares behind the limb, while hardly 60% of PCA's < l dB had their origin on the visible hemisphere. While the sources of GLE's and of PCA's in general, are centered around 50°W which corresponds to the average curvature of the magnetic field lines in interplanetary space, the strongest PCA's (> 8.5 dB) show an anomalous longitude distribution centered around ∼ 20°W. It is suggested that this anomaly may be a consequence of the fact that in strong PCA events the kinetic energy density of protons below 100 MeV becomes comparable to the magnetic energy density in space, thus leading to a ‘straightening’ of the magnetic field lines.  相似文献   

Is special relativity a key to the ‘enigma’ of non-locality phenomenon,in the end?     

Pavel Voráček 《Astrophysics and Space Science》1989,155(2):341-343

An idea is put forward that the events considered in the non-locality phenomenon are co-local and simultaneous in the reference frame of information moving with the velocity of light. Then, the special relativity can explain many aspects of the issue. Furthermore, the impact of the idea is discussed in relation to problems of the Mach principle and those of the Planck era connected to the closeness or openess of our Universe.  相似文献   

Topology of magnetodynamic flows: Kinetic and internal energy of a one-fluid plasma     

A. Hruška 《Planetary and Space Science》1982,30(7):701-709

A mathematical formalism describing the relation between the structure of a one-fluid, collisionless plasma and the topological features of the vector lines of the magnetic, velocity and electric fields is suggested and a rigorous approach to the problem of determining the local features of the plasma from the properties of the velocity field v, observed at a chosen point of space, is developed. The limits to drawing conclusions from the observational data (such as encountered in magnetospheric physics) are outlined in Section 2.Energization of a plasma during a stationary convection is an example of a process characterized by the properties of the tensor $\text{V}\text{= grad}\text{v}$. In particular, if the plasma density and the velocity and pressure components in a volume element of the plasma are known, then the time rates of change of the kinetic and internal energies are described by stretchings of the element and by its shearing in the surface defined by the vectors of magnetic field and perpendicular velocity. Criteria according to which plasma gains or loses kinetic and internal energies are derived.  相似文献   

Radial velocities in the open cluster IC 2602     

Beatriz García  Carlos Hernández  Stella Malaroda  Nidia Morrell  Hugo Levato 《Astrophysics and Space Science》1988,148(1):163-173

We determined radial velocities for 25 probable members of the open cluster IC 2602. We identified the stars with variable radial velocity. We improved the orbit of HD 93030, and computed a preliminary orbit for another spectroscopic binary. We discussed with such data the average cluster radial velocity and we compare the incidence of short period binaries among the Main-Sequence members of IC 2602 with the incidence for other clusters with different values of the average axial rotation of their members.Cerro Tololo Interamerican Observatory operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.  相似文献   

Glassy orthopyroxene granodiorites of the Pannonian Basin: tracers of ultra-high-temperature deep-crustal anatexis triggered by Tertiary basaltic volcanism     

Monika?HuraiováEmail author  Jean?Dubessy  Patrik?Kone?ny  Klaus?Simon  Ján?Král’  Grzegorz?Zielinski  Jozef?Lipka  Vratislav?Hurai 《Contributions to Mineralogy and Petrology》2005,148(5):615-633

Glassy orthopyroxene granodiorite-tonalite (named pincinite after type locality) was described from basaltic lapilli tuffs of the Pliocene maar near Pinciná village in the Slovakian part of the Pannonian Basin. Two pincinite types exhibit a qualitatively similar mineral composition (quartz, An_20–55 plagioclase, intergranular silicic glass with orthopyroxene and ilmenite, ±K-feldspar), but strongly different redox potential and formation PT conditions. Peraluminous pincinite is reduced (6–7% of total iron as Fe³⁺ in corundum-normative intergranular dacitic glass) and contains ilmenite with 8–10 mol% Fe₂O₃ and orthopyroxene dominated by ferrosilite. High-density (up to 0.85 g/cm³) primary CO₂ inclusions with minor H₂, CH₄, H₂S, CO and N₂ (<2 mol% total) are present in Qtz and Plg. Equilibrium PT conditions inferred from the intergranular Opx–Ilm–Glass assemblage and fluid density correspond to 1,170±50°C, 5.6±0.4 kbar, respectively. Metaluminous pincinite is more oxidised (25–27% of total iron as Fe³⁺ in diopside-normative intergranular glass of rhyolite–trachyte–dacite composition) and contains Fe₂O₃-rich ilmenite (17–29 mol%) associated with enstatite. Fluid inclusions are composed of CO₂–H₂O mixtures with up to 38 mol% H₂O. Raman spectroscopy revealed H₂S along with dominant CO₂ in the carbonic phase. Equilibrium PT parameters for the intergranular Opx–Ilm–Glass assemblage correspond to 740±15°C, 2.8±0.1 kbar, respectively. Reducing gas species (<2 mol% total) in the CO₂-inclusions of the peraluminous pincinite resulted from hydrogen diffusion due to fH₂ gradient imposed during decrease of redox potential from the log fO₂ values near QFM during Qtz + Plg growth, to QFM-2 incidental to the superimposed Opx + Ilm assemblage in the intergranular melt. The decrease in oxygen fugacity was recorded also in the metaluminous pincinite, where log fO₂ values changed from ~QFM + 2.6 to QFM + 0.4, but hydrogen diffusion did not occur. Absence of OH-bearing minerals, major and trace element abundances (e.g. REE 300–320, Nb 55–57, Th 4–31, Zr 240–300 ppm, FeO_tot/MgO up to 11), and Sr–O isotope ratios in the pincinites are diagnostic of high-temperature anorogenic magmas originated by dehydration melting of biotite in quartz-feldspathoid crust (⁸⁷Sr/⁸⁶Sr>0.705–0.706, ¹⁸O>9 V-SMOW) around alkali basalt reservoir in depths between 17 and 20 km, and around late stage derivatives of the basalt fractionation, intruding the crust up to depths of 10–11 km. Low water activity in the pincinite parental melt was caused by CO₂-flux from the Tertiary basaltic reservoirs and intrusions. The anatexis leads to generation of a melt-depleted granulitic crust beneath the Pannonian Basin, and the pincinites are interpreted as equivalents of igneous charnockites and enderbites quenched at temperatures above solidus and unaffected by sub-solidus re-equilibration and metamorphic overprint.  相似文献   

Preliminary Quantitative Assessment of Earthquake Casualties and Damages   总被引：4，自引：2，他引：2  

José?Badalmiguelvb@unizar.es" title="badal@unizar.es  miguelvb@unizar.es" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author  Miguel?Vázquez-prada  álvaro?González 《Natural Hazards》2005,34(3):353-374

Prognostic estimations of the expected number of killed or injured people and about the approximate cost associated with the damages caused by earthquakes are made following a suitable methodology of wide-ranging application. For the preliminary assessment of human life losses due to the occurrence of a relatively strong earthquake we use a quantitative model consisting of a correlation between the number of casualties and the earthquake magnitude as a function of population density. The macroseismic intensity field is determined in accordance with an updated anelastic attenuation law, and the number of casualties within areas of different intensity is computed using an application developed in a geographic information system (GIS) environment, taking advantage of the possibilities of such a system for the treatment of space-distributed data. The casualty rate, defined as the number of killed people divided by the number of inhabitants of the affected region, is also computed and we show its variation for some urban concentrations with different population density. For a rough preliminary evaluation of the direct economic cost derived from the damages, equally through a GIS-based tool, we take into account the local social wealth as a function of the gross domestic product of the country. This last step is performed on the basis of the relationship of the macroseismic intensity to the earthquake economic loss in percentage of the wealth. Such an approach to the human casualty and damage levels is carried out for sites near important cities located in a seismically active zone of Spain, thus contributing to an easier taking of decisions in emergency preparedness planning, contemporary earthquake engineering and seismic risk prevention.  相似文献   

Sr-rich minerals in a carbonatite skarn, Fuerteventura, Canary Islands (Spain)     

A. Ahijado  R. Casillas  G. Nagy  C. Fernández 《Mineralogy and Petrology》2005,84(1-2):107-127

Summary Metamorphosed carbonatites and related skarn deposits, located in Fuerteventura Basal Complex, contain unusual Sr-rich minerals. Maximum SrO concentration in the following minerals are: calcite, 7.23wt%; apatite, 5.22wt%; epidote, 11.64wt%; clinozoisite, 1.25wt%; allanite, 5.63wt%; britholite, 4.11wt% and a Sr–Na aluminosilicate (probably stronalsite), 16.44wt% SrO. Calcite and apatite are chemically similar to those found in carbonatites and are therefore considered to be of igneous origin. Textural evidence indicates that the first skarn stage garnet+diopside+Sr–Na aluminosilicate formed as the result of chemical interaction between carbonatites and adjacent silicate rocks. The formation of Sr-bearing epidote/clinozoisite, allanite and britholite appears to be related to the release of Sr into the fluid phase from the breakdown of high temperature assemblages during the retrograde skarn stage. During the final evolution stages, further alteration of britholite by bastnäsite and törnebohmite took place. The occurrence of REE minerals shows that the fluids responsible for this metasomatism must also have transported significant quantities of REE.  相似文献   

Ground magnetic survey of a municipal solid waste landfill: pilot study in Argentina     

C. Prezzi  M. J. Orgeira  H. Ostera  C. A. Vásquez 《Environmental Geology》2005,47(7):889-897

This paper shows the results of a ground magnetic survey carried out to study solid waste landfills. The area located southward of Gualeguaychú town was chosen as a pilot case. This zone was selected considering the available knowledge about the cessation of operations, and the interest of the local authorities in verifying the existence of anomalies indicative of possible dangerous pollutants. The total magnetic field was measured along six profiles, and the corresponding anomalies were calculated. The profiles were modelled in 2.5 D, and along them Eulers deconvolution was used to estimate the depth to the sources. The first and the second derivatives of the residual magnetic field were calculated, in order to sharpen the anomalies. Our interpretation suggests that the characteristics of the modelled bodies and the magnitudes of the detected anomalies do not indicate the presence of drums in the sanitary infill.  相似文献