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91.
Heinz Menzel 《Ocean Dynamics》1949,2(5):169-177
Zusammenfassung Nach einer Theorie von Press und Ewing entsteht die seismische Bodenunruhe dadurch, daß atmosphärische Energie von der Meeresoberfläche in einer Kompressionswelle durch das Wasser auf den Ozeanboden übertragen und im Untergrunde in einer elastischen Welle den Kontinenten zugeleitet wird. Es wird der Effekt der von Press und Ewing vernachlässigten Reibung des Wassers am Meeresboden abgeschätzt. Das wesentlichste Ergebnis der Theorie von Press und Ewing, die quantitativ richtige Erklärung der in der seismischen Bodenunruhe zu beobachtenden Perioden durch den Effekt der Dispersion, bleibt auch bei Berücksichtigung der Reibung näherungsweise erhalten. Der Effekt der Dispersion bei den Wellen, die nach der Wiechertschen Brandungshypothese entstehen würden, wird auch abgeschätzt. Er führt zu einer Periode von 11,9 sec, ein Wert, der etwas zu hoch ist. Die Rechnungsgrundlagen sind aber sehr unsicher.
Herrn Prof. Dr. F. Errulat, seinem verehrten Lehrer, zum 60. Geburtstage gewidmet vom Verfasser. 相似文献
On the theory of microseisms
Summary According to a theory advanced by Press and Ewing atmospheric energy is transmitted to the sea-bottom by compression waves and forwarded to the continents by elastic oscillations of the sub-soil. In the paper that follows an estimate is made of the effect of friction (of the water on the sea-bottom), an effect which has been neglected by Press and Ewing. The outstanding result of their theory, the explanation of the periods observed in microseisms as an effect of dispersion (which is quantitatively correct), is found to remain approximately valid if friction is taken into account. In addition the effect of dispersion is estimated for waves corresponding to Wiechert's surf hypothesis, and a period of 11,9 sec is found, which is somewhat too high. The bases of calculation are, however, by no means reliable.
Herrn Prof. Dr. F. Errulat, seinem verehrten Lehrer, zum 60. Geburtstage gewidmet vom Verfasser. 相似文献
92.
Dr. Ing. Heinz Meinhold 《Pure and Applied Geophysics》1948,12(1-2):14-22
Zusammenfassung Der zeitliche Gang der atmosph?tischen St?rungen ist zwei Einflüssen unterworfen: 1) Der zeitlichen und r?umlichen Verteilung
der St?rquellen, 2) Den jeweiligen Ausbreitungsbedingungen des zu empfangenden Frequenzbandes. Die bei 5,5 MHz durchgeführten
Messungen des atmosph?rischen St?rpegels zeigen den erwarteten Zusammenhang zwischen dem t?glichen Gang und dem Sonnenstand
entsprechend den normalen Ausbreitungsbedingungen im 50 m Band. W?hrend M?gel-Dellinger Effekte nicht festgestellt werden
konnten, ist die Nordlichtst?rung als Folge einer Korpuskularstrahlung der Sonne klar zu erkennen.
Summary The temporal variation of atmospherics is subjected to two facts: 1) The temporal and local distribution of sources of atmospherics, 2) The present conditions of propagation with regard to the just received short-wave band. Measurements of atmospherics in 50 m-band proved the connection between atmospherics and solar-radiation corresponding to the normal conditions of short-wave propagation, showing a minimum at day and a maximum at night. Whilst the Dellinger-effect did not happen, atmospherics disappeard on account of aurora borealis and strong disturbance of the earth's magnetic field, in consequence of corpusculare-radiation of the sun. Monthly distribution of atmospherics in 50 m-band for 2 years measurements are given.相似文献
93.
Heinz Kohnen 《Ocean Engineering》1976,3(5):343-360
The transportation of rich mineral resources from the Arctic by means of large ice-going bulk and oil carrier, is expected to be a suitable and economical technique. The construction of such large vessels requires the knowledge of various glaciological parameters of the sea ice and their dependence on Arctic environmental conditions. Of particular interest on the small scale are the strength, elasticity, and metal to ice friction characteristics, on a larger geophysical scale relevant parameters are the ice stress, pressure, and movement rates and the relation of these parameters to the temperature and salinity of the ice and to the wind field and the ocean current. Furthermore electrical and electromagnetical properties of the ice are relevant to the navigation in ice covered waters by the aid of remote sensing techniques.The German shipyard A.G. Weser in Bremen initiated in 1972 an expedition to the Canadian Arctic to study all relevant physical properties at one location and at the same time to comprehend the whole glaciological regime. The expedition was a cooperative effort between Brook University, St. Catherines (Canada) and the University of Münster (W. Germany). The field measurements were carried out in May and June 1972 on the sea ice between Pond Inlet (Northern Baffin Island) and Bylot Island, N.W.T. This article sumarizes the essential results and presents a synthesis of all the results. 相似文献
94.
95.
Eric Christopher Merten Jacques Finlay Lucinda Johnson Raymond Newman Heinz Stefan Bruce Vondracek 《水文研究》2011,25(4):593-602
Wood deposited in streams provides a wide variety of ecosystem functions, including enhancing habitat for key species in stream food webs, increasing geomorphic and hydraulic heterogeneity and retaining organic matter. Given the strong role that wood plays in streams, factors that influence wood inputs, retention and transport are critical to stream ecology. Wood entrapment, the process of wood coming to rest after being swept downstream at least 10 m, is poorly understood, yet important for predicting stream function and success of restoration efforts. Data on entrapment were collected for a wide range of natural wood pieces (n = 344), stream geomorphology and hydraulic conditions in nine streams along the north shore of Lake Superior in Minnesota. Locations of pieces were determined in summer 2007 and again following an overbank stormflow event in fall 2007. The ratio of piece length to effective stream width (length ratio) and the weight of the piece were important in a multiple logistic regression model that explained 25% of the variance in wood entrapment. Entrapment remains difficult to predict in natural streams, and often may simply occur wherever wood pieces are located when high water recedes. However, this study can inform stream modifications to discourage entrapment at road crossings or other infrastructure by applying the model formula to estimate the effective width required to pass particular wood pieces. Conversely, these results could also be used to determine conditions (e.g. pre‐existing large, stable pieces) that encourage entrapment where wood is valued for ecological functions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
96.
Manolis Plionis Hrant M. Tovmassian Heinz Andernach † 《Monthly notices of the Royal Astronomical Society》2009,395(1):2-10
We revisit the issue of the recent dynamical evolution of clusters of galaxies using a sample of Abell, Corwin & Olowin (ACO) clusters with z < 0.14 , which has been selected such that it does not contain clusters with multiple velocity components nor strongly merging or interacting clusters, as revealed in X-rays. We use as proxies of the cluster dynamical state the projected cluster ellipticity, velocity dispersion and X-ray luminosity. We find indications for a recent dynamical evolution of this cluster population, which however strongly depends on the cluster richness. Poor clusters appear to be undergoing their primary phase of virialization, with their ellipticity increasing with redshift with a rate dε/d z ≃ 2.5 ± 0.4 , while the richest clusters show an ellipticity evolution in the opposite direction (with dε/d z ≃−1.2 ± 0.1 ), which could be due to secondary infall. When taking into account sampling effects due to the magnitude-limited nature of the ACO cluster catalogue we find no significant evolution of the cluster X-ray luminosity, while the velocity dispersion increases with decreasing redshift, independent of the cluster richness, at a rate dσ v /d z ≃−1700 ± 400 km s−1 . 相似文献
97.
Heinz Sulser Diego García-Ramos Peter Kürsteiner Ursula Menkveld-Gfeller 《Swiss Journal of Geoscience》2010,103(2):257-272
Terebratuloid and cancellothyridoid brachiopods from the South-Helvetic Lutetian (Eocene) of the Fäneren region (NE Switzerland) are described: Carneithyris subregularis (Quenstedt) and two forms of Terebratulina s.l. under open nomenclature. Several species of Alpine and non-Alpine origin, related to Carneithyris subregularis, like Terebratula kickxi Galeotti, Terebratula aequivalvis Schafhäutl and Terebratula hilarionis Davidson show characters, which compare well with Carneithyris subregularis. Two of them, T. aequivalvis and T. hilarionis, are assigned to the genus Carneithyris. The stratigraphy and lithology of the sediments in the study area are reassessed. Life habits and palaeoecology of the brachiopods are discussed. C. subregularis apparently was a free living brachiopod without attachment to the substrate, as indicated by massive accumulations of callosities in the posterior parts of the shell. The variability of the cardinal process, as seen in the studied Carneithyris group can be interpreted as a morphological element to enlarge the surface of attachment of strong diductor muscles in relation to the internal thickening of the individual. 相似文献
98.
During the hot summer of 2003, reduction of an ice field in the Swiss Alps (Schnidejoch) uncovered spectacular archaeological hunting gear, fur, leather and woollen clothing and tools from four distinct windows of time: Neolithic Age (4900 to 4450 cal. yr BP), early Bronze Age (4100–3650 cal. yr BP), Roman Age (1st–3rd century AD), and Medieval times (8–9th century AD and 14–15th century AD). Transalpine routes connecting northern Italy with the northern Alps during these slots is consistent with late Holocene maximum glacier retreat. The age cohorts of the artefacts are separated which is indicative of glacier advances when the route was difficult and not used for transit. The preservation of Neolithic leather indicates permanent ice cover at that site from ca. 4900 cal. yr BP until AD 2003, implying that the ice cover was smaller in 2003 than at any time during the last 5000 years. Current glacier retreat is unprecedented since at least that time. This is highly significant regarding the interpretation of the recent warming and the rapid loss of ice in the Alps. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
99.
Abstract— We carried out a petrologic and instrumental neutron activation analysis (INAA) whole chondrite compositional study of Grosvenor Mountains (GRO) 95577. GRO 95577 has many petrological similarities to the CR chondrites. Although the INAA data show patterns indicative of terrestrial weathering, some of the elemental abundances are consistent with a relationship to CR chondrites. The oxygen isotopic composition of GRO 95577 plots close to the Renazzo CR chondrite on the three‐isotope diagram. However, GRO 95577 is remarkable in that the chondrules are completely hydrated, consisting almost entirely of phyllosilicates, magnetite, and sulfides. Although GRO 95577 is completely hydrated, the initial chondrule textures are perfectly preserved. The chondrules are in sharp contact with the matrix, their fine‐grained rims are clearly visible, and the boundaries of the dark inclusions can be easily discerned. Many chondrules in GRO 95577 have textures suggestive of type I chondrules, but the phenocrysts have undergone perfect pseudomorphic replacement by yellow to brownish serpentine‐rich phyllosilicate, with sharp original crystal outlines preserved. The chondrule mesostasis is a green aluminous chlorite‐rich material, most likely a hydration product of the feldspathic mesostasis commonly found in anhydrous type I chondrules. Some chondrules contain magnetite spheres, most likely formed by oxidation of metal. We propose that GRO 95577 be classified as a CR1 chondrite, making it the first known CR1 chondrite and expanding the range of alteration conditions on the CR parent body. 相似文献