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  • 1
    Electronic Resource
    Electronic Resource
    Variations of theD-region aeronomical parameters under non-equilibrium conditions (1973)
    Springer
    Pure and applied geophysics 109 (1973), S. 1862-1869 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Résumé Dans le présent travail on a procédé à une expérience pour déterminer les variations temporelles des principaux paramètres aéronomiques en utilisant des données expérimentales par la méthode A3 de mesure de l'absorption ionosphérique, la méthode ‘phase-altitude’ et des données satellites aux rayons X durs. On a examiné les variations diurnes et les variations temporelles lors de SID effet durant le 21 Août 1969, de la densité électroniqueN(t) et du coefficient de récombinaison α′(t). On a montré que lors de SID effet α′(t) s'accroît.
    Notes: Summary In this paper an attempt is made to define the time variations of theD-region main aeronomical parameters under non-equilibrium conditions by using experimental data by the A3 method, phase-height method and satellite data for the short-wave X-radiation. The SID effect of day-time and time variations of 21 August 1969 electron concentrationN(t) and recombination coefficient α′(t) are investigated. It is shown that during SID effect α′(t) increases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00876110
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental examination of the possible influence of the 1.87 Å line emission on the fine structure of the lower ionosphere ionization (1978)
    Springer
    Pure and applied geophysics 116 (1978), S. 1-7 
    Details
    ISSN: 1420-9136
    Keywords: Continuous emission ; Fine structure ; Ionosphere ; Line emission
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary From the theoretical investigation ofLetfus andApostolov (1974) it follows that under flare conditions the intensive X-ray emission lines in the 1–8 Å range have an insignificant contribution to the ionization state of the lower ionosphere in comparison with the enhanced emission of the continuum. This result is experimentally confirmed by direct comparison of the intensity variations of the emission line 1.87 Å (Fe XXV) during the solar flare of 25 July 1967 measured onboard of the OSO III satellite with simultaneous ground observations of the ionization state variations of the lower ionosphere made by the A3 method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00878981
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  • 3
    Electronic Resource
    Electronic Resource
    A model of non-monotonically growingN(h) profiles of the lower ionosphere under non-flare conditions (1974)
    Springer
    Pure and applied geophysics 112 (1974), S. 635-645 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Résumé L'on propose une idée de l'explication de l'existence du minimum local desN(h) profils qui existe dans la gamme d'altitude 65–75 km aux conditions non-éruptives. Ce minimum est due à dominante influence deL α rayonnement envers cette de rayons X à l'altitude vers 70 km. L'on propose un modèle deN(h) profils qui est approximatif par trois fonctions exponentielles et une fonction parabolic sur la base de modèles [21–24]. Ces profils on peut déterminer par la méthode A3 de mesure de l'absorption ionospheric du minimum deux frequences de mesure, coordonnées avec l'incidence vertical par la méthode A1.
    Notes: Summary An idea is suggested to explain the existence of a local minimum in theN(h) profiles which is in the height range of 65–75 km under non-flare conditions. This minimum is due to the dominating ionizing influence of theL α radiation towards the influence of the X radiation at heights around 70 km. A model ofN(h) profiles is suggested approximated by three exponential and one parabolical functions on the basis of the models [21–24]. These profiles may be obtained by measuring the absorption from a minimum of two measuring frequencies by the A3 method, combined with the vertical sounding by the A1 method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00876803
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  • 4
    Electronic Resource
    Electronic Resource
    Contribution of the X-ray emission lines to ionization of lower ionosphere (1974)
    Springer
    Pure and applied geophysics 112 (1974), S. 647-653 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary In the case of solar flares, X-ray flux shorter than 8 Å fully controls the ionization conditions of the lower ionosphere. Therefore, it should be expected that the energy spectrum distribution shorter than 8 Å determines the form of the height profile of the electron production rate. It is shown analytically that the existing emission lines within the range of 1–8 Å under flare conditions contribute insignificantly to the ionization state of the lower ionosphere. Only two of the most powerful lines Fe XXV (1.850 Å) and the triplet Ca XIX (3.174 Å; 3.187 Å; 3.187 Å; 3.207 Å) are considered for ionization effects. It is shown that the increase of the electron production rate at the height of the maximum ionization of these lines is negligibly small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00876804
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  • 5
    Electronic Resource
    Electronic Resource
    Spectral energy contributions of quasi-periodic oscillations (2–35 days) to the variability of the foF2 (1998)
    Springer
    Annales geophysicae 16 (1998), S. 168-175 
    Details
    ISSN: 0992-7689
    Keywords: Ionosphere ; Ionosphere-atmosphere interactions ; Mid-latitude ionosphere ; Plasma waves and instabilities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The relative contributions of quasi-periodic oscillations from 2 to 35 days to the variability of foF2 at middle northern latitudes between 42°N and 60°N are investigated. The foF2 hourly data for the whole solar cycle 21 (1976–1986) for four European ionospheric stations Rome (41.9°N, 12.5°E), Poitiers (46.5°N, 0.3°E), Kaliningrad (54.7°N, 20.6°E) and Uppsala (59.8°N, 17.6°E) are used for analysis. The relative contributions of different periodic bands due to planetary wave activity and solar flux variations are evaluated by integrated percent contributions of spectral energy for these bands. The observations suggest that a clearly expressed seasonal variation of percent contributions exists with maximum at summer solstice and minimum at winter solstice for all periodic bands. The contributions for summer increase when the latitude increases. The contributions are modulated by the solar cycle and simultaneously influenced by the long-term geomagnetic activity variations. The greater percentage of spectral energy between 2 to 35 days is contributed by the periodic bands related to the middle atmosphere planetary wave activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-0168-9
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  • 6
    Electronic Resource
    Electronic Resource
    First observation of quasi-2-day oscillations in ionospheric plasma frequency at fixed heights (1998)
    Springer
    Annales geophysicae 16 (1998), S. 609-617 
    Details
    ISSN: 0992-7689
    Keywords: Ionosphere (Ionosphere - atmosphere interactions; Mid-latitude ionosphere; Plasma waves and instabilities)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The existence and development of the quasi-2-day oscillations in the plasma frequency variations of the F region at northern middle latitudes are investigated. A new approach to study the quasi-2-day oscillations is presented, using a methodology that allows us to do such a study at fixed heights. The hourly values of plasma frequency at fixed heights, from 170 km to 220 km at 10 km step, obtained at the Observatori de l’Ebre station (40.8°N, 0.5°E) during 1995 are used for analysis. It is found that quasi-2-day oscillations exist and persisted in the ionospheric plasma frequency variations over the entire year 1995 for all altitudes investigated. The dominant period of oscillation ranges from 42 to 56 h. The amplitude of oscillation is from 0.1 MHz to 1 MHz. The activity of the quasi-2-day oscillation is better expressed during the summer half year when several enhancements, about 15–30 days in duration, were observed. The largest enhancements of the oscillation occurred during early June, July and early August; i. e., near and after the summer solstice when the 2-day wave in the middle neutral atmosphere typically displays its largest activity in the Northern Hemisphere. The results obtained may help us understand better the possible influencing mechanisms between the 2-day wave in the middle neutral atmosphere and the ionospheric quasi-2-day oscillations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-0609-5
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  • 7
    Electronic Resource
    Electronic Resource
    A retarding potential analyzer for rocket experiments
    Amsterdam : Elsevier
    Advances in Space Research 2 (1982), S. 89-92 
    Details
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0273-1177(82)90156-9
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  • 8
    Electronic Resource
    Electronic Resource
    Long-period fluctuations observed in the ionospheric absorption variations (1987)
    Springer
    Studia geophysica et geodaetica 31 (1987), S. 301-314 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Description / Table of Contents: Summary By subsequent application of power spectrum analysis, autocorrelation analysis and fast Fourier transform (FFT) of the day- and night-time absorption values of five LF radio-paths (164 kHz, 155 kHz, 185 kHz, 218 kHz and 272 kHz) in Europe during the interval 1 June 1979–30 June 1980, fluctuations with the following basic (fundamental), commonly recurrent periods were found: 3.5–5 days and 10.5–12 days. They exist in all investigated time series, while 6- and 9-day fluctuations are observed on the northern radio-paths (185 kHz and 272 kHz). Shorterperiod oscillations are most active during autumn and especially during winter, while the longerperiod oscillation (10.5–12-day) has significant amplitudes also in summer.
    Notes: Резюме С nомощыо nосле¶rt;овamельно о nрuмененuя aнaлuзa сnекmрa мощносmu, aвmокорреляцuонно о aнaлuзa u бысmроŭ Фурье mрaнсформaцuu (БФТ) к ¶rt;невным u ночным ¶rt;aнным nо nо лощенuю uз nяmu НЧ рa¶rt;uо mрaсс (164 кГц, 155 кГц, 185 кГц, 218 кГц u 272 кГц) нa¶rt; Евроnоŭ в nерuо¶rt; 1 uюня 1979–30 uюня 1980 . былu нaŭ¶rt;ены сле¶rt;ующuе основные (фун¶rt;aменmaльные) nовmоряющuеся nерuо¶rt;ы: 3.5–5 ¶rt;неŭ u 10.5–12 ¶rtнеŭ. Онu nрuсрmсmвуюm во всех uссле¶rt;овaнных временных ря¶rt;aх. 6- u 9-суmочные колебaнuя нaблю¶rt;aюmся mолько в более северных рa¶rt;uоmрaссaх (185 кГц u 272 кГц). Плaнеmaрные колебaнuя сaмые aкmuвные осенью u осенью u особенно зuмоŭ. Более ¶rt;ол оnерuо¶rt;ные волны (10.5–12 ¶rt;неŭ) uмеюm знaчumельную aмnлumу¶rt;у u леmом.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01624760
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  • 9
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    Role of EndoG in development and cell injury (2007)
    Springer Nature
    Details
    Publication Date: 2007-08-31
    Print ISSN: 1350-9047
    Electronic ISSN: 1476-5403
    Topics: Biology , Medicine
    Published by Springer Nature
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  • 10
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    A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator (2020)
    Springer Nature
    Details
    Publication Date: 2020-05-18
    Print ISSN: 1749-4885
    Electronic ISSN: 1749-4893
    Topics: Physics
    Published by Springer Nature
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