HENRY GEORGES FOURCADE     

L. P. Adams 《The Photogrammetric Record》1975,8(45):287-296

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Diffuse cosmic gamma-ray background in the 28 ke V-4.1 MeV range from Kosmos 461 observations     

E. P. Mazets  S. V. Golenetskii  V. N. Il'inskii  Yu. A. Gur'yan  T. V. Kharitonova 《Astrophysics and Space Science》1975,33(2):347-357

Diffuse cosmic background and atmospheric gamma-radiation in the range 28 keV-4.1 MeV were studied with a scintillation spectrometer on board of the Kosmos 461 satellite. Separation of the cosmic and atmospheric components was made possible through a reliable determination of the geomagnetic dependences of albedo gamma-radiation: The spectrum of diffuse background in the energy range covered cannot be fitted with a common law. At energies below 400 keV the spectrum follows a power-law $$I = (5.6 \pm 0.5) \times 10^{ - 3} E^{ - (2.80 \pm 0.05)} cm^{ - 2} s^{ - 1} sr^{ - 1} MeV^{ - 1} .$$ Starting from 400 keV, this power-law breaks down; the spectrum revealing a clearly pronounced shoulder. Extrapolation of the power-law spectrum to higher energies shows that the gamma-ray component responsible for the change in the shape of the spectrum is quite strong, becoming predominant in the diffuse background in the range 1–100 MeV. The intensity of excess radiation is maximum in the region of 700–800 keV reaching ～1.8×10^?2 cm^?2s^?1sr^?1 MeV^?1. The shape of the high energy component spectrum of the diffuse background constructed using the data of Kosmos 461 and SAS-2 is in agreement with the hypotheses of the cosmological origin of the radiation.  相似文献   

Solid-Fluid Equilibria in the System KAlSi3O8-NaAlSi3O8-Al2SiO5-SiO2-H2O-HCl     

WINTSCH  ROBERT P. 《Journal of Petrology》1975,16(1):57-79

Activity diagrams in the system KAlSi₃O₈-NaAlSi₃O₈-Al₂SiO₅-SiO₂-H₂O-HClhave been calculated in terms of a_K+/a_H+ and a_N+/a_H+ from existingexperimental data. They show the effect of temperature, pressure,and a_H2O on the stability fields of the alkali feldspars, micas,and aluminium silicate. These activity diagrams are useful in revealing the bufferingcapacity of mineral assemblages and the chemical potential gradientsestablished by changes in T, P, a_H2O, and mineral assemblage.An analysis of mineral paragenesis in terms of these diagramssuggests that mosaic equilibrium, allowing limited metasomatismand internal buffering of chemical potentials, best describemetamorphic systems. Thus the dehydration reaction: muscovite+quartz=K-feldspar+Al₂SiO₅+H₂O which is most important in closed systems, probably fails todescribe in detail the mechanism of natural muscovite decomposition.Rather the decomposition of muscovite is more likely representedby ionic reactions. The replacement of muscovite by feldspar: muscovite+6 SiO₂+2 K⁺=3 K-feldspar+2 H⁺ muscovite+6 SiO₂+3 Na⁺=3 Albite+K⁺+2 H⁺ is favored at high temperature and low pressure, and may accountfor the crystallization of some feldspars in metamorphic rocks.The reaction involving aluminium silicate replacement of muscovite: 2 muscovite+2 H⁺=3 Al₂SiO₅+3 SiO₂+3 H₂O+2 K⁺ is favored at high temperature and pressure and low a_H2O, andcould contribute to the development of the aluminium silicates.It is concluded that both activity diagrams and AKNa projectionsshould be used together to more completely evaluate mineralparagenesis in terms of mosaic equilibria.  相似文献   

The July 1974 solar events: A possible lower limit for microwave activity     

P. Kaufmann  P. Iacomo Jr.  E. H. Koppe  P. Marques Dos Santos  R. E. Schaal  J. R. Blakey 《Solar physics》1975,45(1):189-197

The active region McMath 10433 was the source of several flares and radio outbursts during the early part of July 1974. This region was tracked continuously, for several periods during the month at 22.2 GHz using a telescope with a 4 beam. Comparison with the results obtained simultaneously with a normal 7 GHz solar patrol instrument indicate that there is important burst activity occurring at levels below the detection limit of normal solar patrol instruments. The time-development morphology of these bursts is similar to those normally observed and has enabled the simple events to be re-interpreted. A completely new type of event - the fast absorption - has also been recognized. The correlation of the microwave events with SPA events observed on VLF propagation is also discussed.Spending a sabbatical year at CRAAM, São Paulo, Brazil.  相似文献   

Observations of the structure and evolution of solar flares with a soft X-ray telescope     

J. A. Vorpahl  E. G. Gibson  P. B. Landecker  D. L. McKenzie  J. H. Underwood 《Solar physics》1975,45(1):199-216

132 soft X-ray flare events have been observed with The Aerospace Corporation/Marshall Space Flight Center S-056 X-ray telescope that was part of the ATM complement of instruments aboard Skylab. Analyses of these data are reported in this paper. The observations are summarized and a detailed discussion of the X-ray flare structures is presented. The data indicated that soft X-rays emitted by a flare come primarily from an intense well-defined core surrounded by a region of fainter, more diffuse emission. Loop structures are found to constitute a fundamental characteristic of flare cores and arcades of loops are found to play a more important role in the flare phenomena than previously thought. Size distributions of these core features are presented and a classification scheme describing the brightest flare X-ray features is proposed. The data show no correlations between the size of core features and: (1) the peak X-ray intensity, as indicated by detectors on the SOLRAD satellite; (2) the rise time of the X-ray flare event, or (3) the presence of a nonthermal X-ray component. An analysis of flare evolution indicates evidence for preliminary heating and energy release prior to the main phase of the flare. Core features are found to be remarkably stable and retain their shape throughout a flare. Most changes in the overall configuration seem to be the result of the appearance, disappearance or change in brightness of individual features, rather than the restructuring or re-orientation of these features. Brief comparisons with several theories are presented.  相似文献   

Analysis of the intensities and profiles of the spectral line Mg xii 8.42 Å in the solar X-ray spectrum     

J. Jakimiec  V. V. Korneev  V. V. Krutov  I. A. Zhitnik  S. Pŀocieniak  B. Sylwester  J. Sylwester 《Solar physics》1975,44(2):391-401

High resolution profiles of the Mg xii 8.42 Å line in the solar X-ray spectrum were recorded from the Intercosmos 7 satellite. The Mg xii line intensity provides a sensitive indicator of the hot plasma content (T ? 3 × 10⁶ K) in coronal condensations and X-ray flare volumes. The ratio of the line intensity to the intensity of the adjacent continuum has been used to compute approximate thermal models of the emitting regions. For all the investigated coronal condensations the temperature distribution of plasma has been found to be a function monotonically decreasing with temperature. But for some X-ray bursts there occurred a distinct excess of the hot plasma of temperature between 6–10 × 10⁶K. FWHM values of the Mg xii line profiles have been used to estimate ion temperature in the emitting regions.  相似文献   

Coronal changes associated with a disappearing filament     

N. R. Sheeley Jr.  J. D. Bohlin  G. E. Brueckner  J. D. Purcell  V. E. Scherrer  R. Tousey  J. B. Smith Jr.  D. M. Speich  E. Tandberg-Hanssen  R. M. Wilson  A. C. De Loach  R. B. Hoover  J. P. Mc Guire 《Solar physics》1975,45(2):377-392

This paper describes Skylab/ATM observations of the events associated with a disappearing filament near the center of the solar disk on January 18, 1974. As the filament disappeared, the nearby coronal plasma was heated to a temperature in excess of 6 × 10⁶K. A change in the pattern of coronal emission occurred during the 11/3 hr period that the soft X-ray flux was increasing. This change seemed to consist of the formation and apparent expansion of a loop-like coronal structure which remained visible until its passage around the west limb several days later. The time history of the X-ray and microwave radio flux displayed the well-known gradual-rise-and-fall (GRF) signature, suggesting that this January 18 event may have properties characteristic of a wide class of X-ray and radio events.In pursuit of this idea, we examined other spatially-resolved Skylab/ATM observations of long-duration X-ray events to see what characteristics they may have in common. Nineteen similar long-lived SOLRAD X-ray events having either the GRF or post-burst radio classification occurred during the nine-month Skylab mission. Sixteen of these occurred during HAO/ATM coronagraph observations, and 7 of these 16 events occurred during observations with both the NRL/ATM slitless spectrograph and the MSFC-A/ATM X-ray telescope. The tabulation of these events suggests that all long-lived SOLRAD X-ray bursts involve transients in the outer corona and that at least two-thirds of the bursts involve either the eruption or major activation of a prominence. Also, these observations indicate that long-lived SOLARD events are characterized by the appearance of new loops of emission in the lower corona during the declining phase of the X-ray emission. However, sometimes these loops disappear after the X-ray event (like the post-flare loops associated with a sporadic coronal condensation), and sometimes the loops remain indefinitely (like the emission from a permanent coronal condensation).Visiting Scientist, Kitt Peak National Observatory, Tucson, Ariz. 85726, U.S.A. operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.Presently located at NASA/MSFC, Space Sciences Laboratory, Marshall Space Flight Center, Ala. 35812, U. S.A.  相似文献   

Velocity-space maps and transforms of tracking observations for orbital trajectory state analysis     

Samuel P. Altman 《Celestial Mechanics and Dynamical Astronomy》1975,11(4):405-428

The orbital state of a satellite in a central force field can be uniquely described by its velocity hodograph, a circle, rather than the Keplerian conic. Also, its coordinate-frame rotation about the attracting center is definable, without singularity, by the four-parameter set of Euler parameters. A unified state model of orbital trajectory and attitude dynamics has previously been developed by use of state variables of the orbital velocity hodograph and Euler parameters. The dynamical constraint equations of this orbital state model are especially effective in advanced techniques of state estimation, used for orbit determination and prediction. External observations of orbital vehicles, such as provided by optical and radar sensors of tracking systems, are transformable into corresponding velocity state maps, as presented in this paper. These transformations and the consequent state maps are essential for development of the orbit observation matrix used with the unified state matrix, in recursive estimators such as the Kalman filters. Line-of-sight rays and range spheres (or hemispheres) of observations map conformally into orthogonal spherical surfaces in velocity space, as the result of the point-contact transformations. In bispherical coordinates, the field of observation maps for a ground-based tracking system site is shown to be a reduced (or degenerate) form of the general field of observation maps for a satellite-based tracking site. These orbital state maps and transforms are directly useful in development of observation matrices for candidate observation sets, such as range only, angle only, or range plus range-rate tracking schemes. Also, surface coverage patterns can be generated for proposed new tracking systems, in mission analysis and system synthesis studies.  相似文献   

A coordinated effort for observations and theories of the natural satellites     

P. K. Seidelmann 《Celestial Mechanics and Dynamical Astronomy》1975,12(1):59-59

It was recognized over a year ago that a requirement to improve the ephemerides of the natural satellites existed and that it might be satisfied by a coordinated effort. Both the national ephemeris offices, which publish the satellite ephemerides, and NASA, which plans to send spacecraft to observe the satellites, require improved ephemerides of the natural satellites, but individually none of the organizations has the personnel or finances to undertake the task alone. At that time a few people and institutions had become interested in or were beginning to work on the theories and to make observations of the satellites. It was apparent that if the efforts of the various people and institutions were coordinated and others were encouraged to contribute, it might be possible in the next five years to satisfy the requirement for improved ephemerides. The coordinated effort includes personnel from the University of Texas, Smithsonian Astrophysical Center, University of Cincinnati, Bureau des Longitudes, Jet Propulsion Laboratory, University of Virginia, Vanderbilt University, Lowell Observatory, NASA Headquarters, and the U.S. Naval Observatory, with the latter institution serving as the coordinator.  相似文献   

Collisional metamorphism as a result of thrusting in the Transangara region of the Yenisei Ridge     

I. I. Likhanov  P. S. Kozlov  N. V. Popov  V. V. Reverdatto  A. E. Vershinin 《Doklady Earth Sciences》2006,411(1):1313-1317

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