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141.
The distortions of the relict radiation spectrum in the region of the wavelength <120 are considered. These distortions are due to the emission of photons under the formation of molecular hydrogen in the expanding universe in the cosmological epoch 40z200. It is shown that the real intensity of the relict radiation in the region of the wavelength under consideration must significantly exceed Planck's intensity, with a radiation temperature amounting to 2.8 K.  相似文献   
142.
This study deals with the short-term variations of cosmic ray intensity during the interval 1973–78. Daily means of high latitude neutron and meson monitors from the same station and those of a low latitude neutron monitor have been analysed using the Chree method of superposed epochs. The zero epoch for the Chree analyses corresponds to the day of a substantial increase (V 200 km s–1) in the solar wind speed to values of 550 km s–1 and which persists at such high values for an interval of at least three days. The investigation reveals the existence of two types of cosmic ray intensity variations with distinctly different spectral characteristics. During the interval 1973–76, relative changes in the neutron and meson monitor rates are nearly equal indicating an almost flat rigidity spectrum of variation. During 1977–78, however, the spectrum acquires a negative spectral character similar to that observed for Forbush decreases. We suggest that events of the interval 1973–76 are essentially due to high speed streams associated with solar coronal holes and that events of the interval 1977–78 are due to fast streams from solar active regions with flare activity.  相似文献   
143.
Situations arise in celestial mechanics where orbital eccentricities are large and yet it is desirable to maintain the Darwin-Kaula Fourier decomposition of the perturbing function. Evaluation of the appropriate eccentricity functionsG lpq (e) requires a double summation which, for practical purposes, must be truncated. In this note criteria have been established for truncation of the expansion for eccentricities 0.75.  相似文献   
144.
The microstructural and X-ray diffraction characteristics of natural K-bearing cordierites in buchites (Blaue Kuppe, Germany), and paralavas (Bokaro, India) are compared to those of three suites of synthetic, K-bearing Mg-cordierite, studied after annealing glasses of the requisite compositions for durations between 5 min and 255 days at 1,290° C and 1 bar. In analogy to pure Mg-cordierite, hexagonal high-cordierite initially crystallizes from the glass and subsequently transforms to orthorhombic low-cordierite. After annealing for 30–60 min, the crystals develop tweed-structure. With prolonged annealing, the pattern coarsens and develops into lamellar twinning. Higher K-contents favour earlier development of tweed-contrast. Distortion indices obtained by X-ray powder diffraction show a sharp initial increase of with annealing time, followed by a levelling off after approximately 10 h. Higher K-contents delay this initial increase, and decrease drastically the maximum distortion index that can be attained. The contrasting observations with respect to increasing K-content are due to the different levels of information yielded by TEM and X-ray diffraction. Analyses of electron diffraction patterns indicate that the metric state of individual crystals in any single sample annealed for more than one hour is highly heterogeneous, while no compositional differences could be detected. Hexagonal and variously distored crystals coexist. Thus intermediate structural states of cordierite in the classical sense are shown to exist, although intermediate distortion indices obtained by routine X-ray powder diffraction are largely due to a summation effect over such structurally heterogeneous populations. Although distinct differences in microstructure between the synthetic and the natural Fe2+-bearing cordierites exist, the Bokaro samples most closely resemble the early (1–10 h) tweed-structure of the synthetic products, whereas the Blaue Kuppe samples are comparable to a more mature (1–3 days) stage. It is thus concluded that the cordierite-bearing Bokaro paralavas cooled considerably faster than the Blaue Kuppe buchites.  相似文献   
145.
The goals of the TREK experiment, now in place on the MIR Space Station, are to resolve and measure the composition of both odd-Z and even-Z cosmic-ray nuclei up to uranium, to measure the isotopic composition of Fe-group nuclei, and to search for transuranic nucleic and exotic particles such as strangelets. To collect tracks of ultraheavy cosmic rays, exterior panels holding an array of BP-1 phosphate glass 1.2m2 in area and 16 plates thick are now mounted outside the Kvant-2 module on MIR. Heaters and relays regulate the temperature of the glass at 25°±5°C. The detectors will record 103 cosmic-ray tracks withZ50 during 2.5 years. An interior panel consisting of an array 0.09 m2 in area and 32 plates thick and mounted on the inside wall of the Soyuz spacecraft (attached to the Space Station) will collect tracks of about 13000 Fe and 500 Ni nuclei.  相似文献   
146.
The main major ridge belts of Ganiki Planitia on Venus (Lama, Ahsonnutli and Pandrosos Dorsa) are part of the fan-shaped ridge belt complex along the 200 parallel of longitude. These ridge belts with evidence of crustal shortening support the idea of a large-scale E-W compression. The ridge belt patterns indicate a N-S shear component. These forces are explained by a triangular planitia area which compressed by surrounding terrains. The crustal shortening and ridge belt formation indicates compressional plate movement stresses in the uppermost lithosphere.Three sizes of ridge belt structure are to be found within Ganiki Planitia. (1) The ridge belt spacing of 200–400 km can be used to estimate the depth of the major uppermost homogeneous layer of Venus. There are numerous volcanic coronae, paterae and montes located along the main ridge belts or at their junctions. (2) Mid-size ridge groups or subbelts are to be found within the major ridge belts. These are formed by more local responses to tectonic stresses in the stratified uppermost crust. A wavelength of 40–70 km can be seen as a result of bending of the crustal strata and may relate to its thickness. (3) Small individual ridges are connected with most local stresses, defining places where the surface layers broke along the crests of large ridge belts or mid-scale subbelts. Radial and concentric mare ridge-like structures around coronae indicate that corona formation was effective at a sufficiently close vicinity to fault the surface.  相似文献   
147.
Line-forming regions around close binaries with strong winds ( /4r * v 10–4 g cm–2) are large in extent compared with the stars, large enough to screen them. Their orbitally-modulated Doppler shifts can overestimate the mass function, because of a larger rotational lever arm. In particular, most of the black-hole candidates need not involve companions more massive than a neutron star.The solar-wind problem is reconsidered. An extrapolation to Wolf-Rayet stars suggests that their winds are centrifugally driven. Their mass-loss rates tend to have been overestimated.Seemingly single (massive) stars can hide a (compact) companion.  相似文献   
148.
Roy BK 《GeoJournal》1990,20(3):271-284
In this paper an attempt is made to present some facets of status of water for agriculture and population in India. The issues are basic in nature which have been focused by scholars all over time and again. The materials are gathered from various sources to highlight and to consider a plea in the context of population-hydrological regions of the country to develop water potentials. Some characteristic mapping has also been conducted showing the main parameters of water utilization, need and spatial issues regarding consumptive use of water during agricultural operations as per the seasons prevalent in India. A relation is also established with the drought areas leading to assess the need for water. The human problems specially in relation to the safe drinking water is also projected in relation to distributional qualities with reference to natural regions by districts. The study does not claim a full assessment of the water issue due to paucity of statistics on water use, generation and potentials but it does indicate in many ways the geographical problems as an important study for further research by all concerned.  相似文献   
149.
The reflection seismic line DEKORP 2-N reveals an almost complete cross section through the Rhenohercynian Zone, the most external part of the Variscan orogen in Europe.The northern part of DEKORP 2-N and a NE-directed branch (2-N-Q) reveal the Cretaceous of the Münsterland basin and the underlying folded Palaeozoic rocks. The northward decreasing intensity of folding is depicted in great detail by the highly reflective Late Carboniferous coal-measures and deeper reflections down to the level of the Givetian/Frasnian shallow-water carbonates.In the Devonian and older rocks of the Rhenish Massif, bedding is only represented by relatively weak, short and irregular reflections. These are truncated by stronger, southward dipping reflections, which exhibit the listric curvature and flat/ramp geometry characteristic of faults. In the northern part of the section, the thrusts appear to be blind. From the Ebbe Anticline southwards, prominent reflections can be correlated with important thrust faults known from the surface, such as the Ebbe-, Siegen-, Müsen- and Sackpfeife- Thrusts, as well as further important thrust faults in the Lahn- and Dill Synclines. The basal thrust of the extremely thin-skinned Giessen Nappe is only recognizable for a very short distance.At depth, the thrusts flatten out in a relatively transparent zone between 3–5 s TWT, with strongly reflective bands at its bottom and top. The transparent zone might correlate with a high-conductivity layer detected in a magnetotelluric survey; it represents either graphitic metapelites or a zone with an interconnected, brine-filled pore space. The seismic record relates either to lithological differences, or to rheological boundaries.The lower crust in the north is characterized by a relatively transparent zone, which wedges out towards south under the northern margin of the Siegen Anticline. Comparisons with a similar feature in the ECORS profile »Nord de la France« suggest that the transparent zones in both sections correspond to a pre-Palaeozoic basement, such as it underlies the Brabant Massif. Further south, the lower crust is increasingly reflective.The curvilinear, thrust-related reflections are cut by a conjugate set of much weaker, N- and S-dipping reflectors indicating a later deformation with pure shear. Displacement of some marker reflections suggests late- or post-Variscan compression.In an alternative interpretation, these straight and weak reflections represent the only thrust faults, while the curvilinear elements might relate to bedding.A southward rise of the Moho from approx. 11 to 8.5 s TWT is probably due to Tertiary rifting.
Zusammenfassung Das reflexionsseismische Profil DEKORP 2-N stellt einen fast vollständigen Querschnitt durch das Rhenohercynikum dar.Der nördliche Teil des Profiles 2-N sowie ein SW/NE-verlaufender Abzweig (2-N-Q) zeigen die Transgression der Münsterländer Kreide und das unterlagernde gefaltete Paläozoikum. Schichtgebundene Reflektoren (flözführendes Karbon, devonischer Massenkalk) bilden das Ausklingen der variscischen Faltung nach NW detailliert ab.In den devonischen und vordevonischen Sedimenten des rechtsrheinischen Schiefergebirges erzeugt die Schichtung nur relativ schwache, kurze und unregelmäßige Reflexionen. Diese werden von stärkeren, südfallenden Reflektoren abgeschnitten, die aufgrund ihrer listrischen Krümmung und flat/ramp-Geometrie wahrscheinlich als Überschiebungen zu interpretieren sind. Im Nordteil des Schiefergebirges sind diese Überschiebungen offenbar blind, werden also nahe der Oberfläche durch Faltung kompensiert. Im Ebbe-Sattel und weiter südlich lassen sich die meisten der starken, südfallenden Reflektoren zweifelsfrei mit bekannten Großüberschiebungen korrelieren (Ebbe-, Siegen-, Müsen-, Sackpfeife-Ü, sowie weitere Überschiebungen in der Lahn- u. Dill-Mulde). Die Basisüberschiebung der Giessen-Decke wird nur teilweise abgebildet.Zur Tiefe hin zeigen die Überschiebungen ein zunehmend flacheres Einfallen, und verschwinden in einer relativ transparenten Zone zwischen 3 und 5 s TWT, die im Hangenden und Liegenden durch dünne, stark reflektive Zonen begrenzt ist. Diese transparente Zone entspricht möglicherweise einer Zone hoher integrierter Leitfähigkeit, die in einem begleitenden magnetotellurischen Experiment nachgewiesen worden ist; es handelt sich entweder um einen Graphit-führenden Phyllit-Horizont oder eine mächtigere permeable Zone mit Elektrolyt-gefülltem Porenraum. Die hochreflektiven Bänder über und unter der transparenten Zone entsprechen entweder lithologischen Kontrasten oder rheologischen Grenzen, die vermutlich von einer scherenden Verformung überprägt worden sind.Die Unterkruste im N-Teil des Profiles enthält einen relativ transparenten Bereich, der nach Süden hin unter dem Nordteil des Siegener Sattels keilförmig ausläuft. Ein ähnliches Bild zeigt der Nordteil des ECORS-Profiles »Nord de la France«. Die transparenten Bereiche beider Profile entsprechen wahrscheinlich einem prä-paläozoischen kristallinen Basement, das das Brabanter Massif unterlagert und sich rechtsrheinisch fortsetzt. Südlich des transparenten Keiles wird die Unterkruste zunehmend reflexionsreicher. Die listrisch gekrümmten, an Überschiebungen gebundenen Reflektoren werden von einem konjugierten System schwächerer, N- u. S-fallender Reflektoren abgeschnitten, die auf eine jüngere, bruchhafte Verformung durch reine Scherung hindeuten. Der Versatz einiger älterer Reflektoren deutet auf spät- oder postvariscische Kompression hin.In einer alternativen Interpretation werden nur diese jüngeren Reflektoren als Überschiebungen gedeutet; die älteren, gekrümmten Elemente müßten dann primären lithologischen Grenzen entsprechen.Die Moho steigt von ca. 11 s TWT im N auf 8.5 s TWT unter dem Taunus an. Die Krustenverdünnung im Süden geht wahrscheinlich auf Dehnung im Tertiär zurück.

Résumé Le profil sismique par réflexion DEKORP-2-N représente une transversale quasiment complète à travers la zone rhénohercynienne. La partie septentrionale du DEKORP-2-N ainsi qu'une branche de direction SW-NE (2-N-Q) mettent en évidence la transgression du Crétacé du Münsterland sur le Paléozoïque sous-jacent plissé. Des réflecteurs liés à la stratification (à savoir: le Houiller et les calcaires de plate-forme dévoniens) illustrent de façon détaillée la diminution vers le nord de l'intensité du plissement varisque.Dans les sédiments dévoniens et pré-dévoniens du Massif Rhénan à l'est du Rhin, la stratification ne fournit que que des réflexions relativement faibles, courtes et irrégulières. Elles sont tronquées par des réflecteurs plus intenses, à pendage sud qui, en raison de leur courbure listrique et de leur géométrie en «flat/ramp», doivent être interprétés comme des chevauchements. Dans la partie septentrionale du Massif, ces chevauchements sont apparemment aveugles, c'est-à-dire qu'ils sont compensés, près de la surface, par le plissement. Dans l'anticlinal d'Ebbe, ainsi que plus au sud, la plupart des réflecteurs intenses à plongement sud peuvent être corrélés avec des chevauchements majeurs connus, tels ceux de Ebbe, Siegen, Müsen, Sackpfeife et d'autres encore dans les synclinaux de la Lahn et de la Dill. Le chevauchement basai de la nappe de Giessen n'est que partiellement représenté.Les chevauchements deviennent de plus en plus plats en profondeur pour disparaître dans une zone relativement transparente qui se situe entre 3–5 sec TWT. Celle-ci est prise en sandwich par des zones minces à forte réflectivité. La zone transparente correspond probablement à une zone de conductivité intégrée élevée dont l'existence a par ailleurs été démontrée dans un essai magnétotellurique mené parallèlement. Il s'agit soit d'un horizon phyllitique graphiteux, soit d'une zone perméable plus épaisse dont les pores sont remplis d'électrolyte. Les bandes à haute réflectivité au-dessus et en-dessous de la zone transparente correspondent soit à des contrastes lithologiques, soit à des limites rhéologiques probablement accentuées par la déformation cisaillante.La croûte inférieure dans la partie septentrionale du profil comporte un domaine relativement transparent qui s'amincit vers le S et se termine, en dessous de la partie nord de l'anticlinal de Siegen, en forme de coin. La partie nord du profil ECORS «Nord de la France» montre une image semblable.Les domaines transparents des deux profils correspondent vraisemblablement à un soubassement cristallin pré-paléozoïque qui est sousjacent au Paléozoïque du Massif du Brabant et se prolonge vers l'est au-delà du Rhin. Au sud du coin transparent, la réflectivité de la croûte inférieure va en augmentant. Les réflecteurs listriques liés à des chevauchements sont recoupés par un système conjugué de réflecteurs plus faibles à plongement nord et sud qui indiquent des failles plus récentes. Le déplacement de quelques réflecteurs plus anciens suggère l'effet d'une compression tardiou post-varisque.Dans une interprétation alternative, seuls ces réflecteurs plus récents sont considérés comme correspondant à des chevauchements. Dans ce cas, les éléments courbes plus anciens devraient représenter des limites lithologiques primaires.Le Moho s'élève à partir de 11 sec TWT environ au nord jusqu'à 8.5 sec TWT en-dessous du Taunus. L'amincissement crustal au sud résulterait du régime de distension survenu au Tertiaire.

DEKORP 2 Nord. x-t- ray-tracing'a. 6,0 6,6 /, — 7,0 8,2 /. 6,25 /. 28 30 . , .

Abbreviations MORB Mid-Ocean Ridge Basalt - TWT two-way travel time, seconds (s) - CMP common mid-point - VP vibration point - SNR signal to noise ratio  相似文献   
150.
We present an analysis of the reported spectral features of NGC 4151 in X-rays. It is shown that the origin of X-rays from the source is inconsistent with a single production mechanism. We suggest a new two-component model in which soft X-rays arise from the black-body emission of a tiny hot nucleus withT2×107 K and the hard X-ray photons are generated in an extended region by inverse Compton scattering of electrons with the infrared photons.  相似文献   
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