Mass distribution in the asteroid belt     

Jozef Klačka 《Earth, Moon, and Planets》1992,56(1):47-52

The dependence of the cumulative number of numbered asteroids (up to 3720) on their absolute magnitude is investigated. The differential mass index k is derived from these relations for fainter asteroids. A steeper slope (2.2 < k < 2.4) is found in the four most populous asteroid familes (Flora, Koronis, Eos and Themis) and a flatter slope (1.3 < k < 1.6) for non-family asteroids. This indicates that there are two different asteroid populations in the asteorid belt. Total masses of the asteroid families may be greater than it is commonly accepted.  相似文献   

Zur Frage der Nebelfrostablagerungen im Gebirge     

Mikuláš Konček 《Studia Geophysica et Geodaetica》1960,4(1):69-84

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Heat-capacity measurements and absolute entropy of ɛ-Mg2PO4OH     

Catherine Leyx  J. Cornelis Van Miltenburg  Christian Chopin  Lado Cemič 《Physics and Chemistry of Minerals》2005,32(1):13-18

The low-temperature heat capacity of -Mg₂PO₄OH was measured between 10 and 400 K by adiabatic calorimetry. No phase transition was observed over this temperature range. A relative enthalpy increment of 22,119 J mol^–1 and an absolute entropy value of 127.13±0.25 J mol^–1 K^–1 at 298.15 K are derived from the results. The low-temperature heat-capacity data are compared with the DSC data obtained from 143 K to 775 K and show marginal differences in the common temperature range. The latter data are fitted by the polynomial which allows extrapolation to high temperatures.Software information: WINDOWS operating system, WORD word processing, SigmaPlot diagrams exported in tiff format.  相似文献   

On the effect of lava viscosity on the magnetic fabric intensity in alkaline volcanic rocks     

F. Hrouda  M. Chlupáčová  K. Schulmann  J. Šmíd  P. Závada 《Studia Geophysica et Geodaetica》2005,49(2):191-212

The degree of the anisotropy of magnetic susceptibility (AMS) of basaltic rocks, as is known from the large AMS database of these rocks, is generally very low, while in more acidic volcanic rocks such as andesites, trachytes and phonolites, which have been investigated much less frequently, it is in general much higher. In the present study, the AMS of various volcanic rocks including trachytic and phonolitic rocks was investigated in the Tertiary volcanic region of the eské stedohoí Mts. Viscosities of the respective lavas were calculated from the chemical composition using the KWARE program. A rough correlation was found between the degree of AMS and lava viscosities, probably resulting from different mechanisms orienting the magnetic minerals. In basaltic lava flows this mechanism is traditionally considered to be of a hydrodynamic nature, in trachytic and phonolitic bodies it can also be represented by quasi-intrusive flows resembling, at least partially, ductile flow deformation. This is in agreement with the AMS data predicted by the viscous (liquid flow) and line/plane (ductile flow) models.  相似文献   

Confidence regions in Helmert transformation     

Lubomír Kubáček 《Studia Geophysica et Geodaetica》1966,10(2):124-136

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Photometry of the open cluster NGC 6996 in the North America Nebula     

K. Zdanavičius  V. Straižys 《Astrophysics and Space Science》1990,173(2):309-314

Thirty stars in the direction of the open cluster NGC 6996 are measured in the Vilnius photometric system. Photometric spectral types, absolute magnitudes, interstellar reddenings, extinctions, and distances are determined for most of them. Fifteen stars are suspected to be cluster members. Their mean distance is 620±30 pc and mean extinctionA _v is 1.74 mag. The extinction within the cluster is variable. The age of the cluster is of the order of 10⁸ yr and this excludes the possibility that it is evolutionary related with the North America and Pelican Nebulae complex. The distance of this complex 550 pc is confirmed.  相似文献   

Cooling of a 2-dimensional intrusion     

Josef Bochníček  Pavel Hejda  Reviewer C. Matyska 《Studia Geophysica et Geodaetica》1989,33(3):254-267

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Comparison ofm PV magnitudes (kašperské hory — průhonice — uscgs)     

Dana Procházková  Reviewer K. Pěč 《Studia Geophysica et Geodaetica》1974,18(3):304-306

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Modulation patterns of astronomical imaging systems based on rotating grids     

V. Dadurkevičius  D. A. Ralys 《Astrophysics and Space Science》1985,113(2):233-247

Various astronomical imaging systems use rotating grids as modulators and operate in the optical, X-ray, and gamma-ray regions. The position and strength of each measured source are encoded in a modulation pattern, produced by the imaging system. Here we present the mathematical expressions of the modulation patterns which permit efficient computer implementation and a simple approximate expression is also given which facilitates the understanding of the basic properties of the modulation patterns. Although various modulation devices strongly differ in appearance, their modulation patterns show a remarkable similarity. This suggests that a unified approach is possible by analysing the output signals of these devices.  相似文献   

Book reviews     

Jirî Bičák  Edwin Budding  Jan Novotny  P. Hadrava  Martin Machacek  Jiří Podolsky  J. Kleczek 《Astrophysics and Space Science》1985,111(2):419-424

The possibility of the existence, around type-I supernovae, of dust shells which existed before a supernova outburst is considered. None have so far been detected observationally; and any dust around the progenitor radiating in the near infrared would evaporate at outburst. Far infrared observations of the two possible types of progenitor, R Coronae Borealis-type stars and dwarf novae, would be useful to indicate whether there is any dust around them which would survive a supernova outburst.  相似文献