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541.
Kalle Olli Christian Wexels Riser Paul Wassmann Tatjana Ratkova Elena Arashkevich Anna Pasternak 《Progress in Oceanography》2001,51(2-4)
Lagrangian experiments with short-term, drifting sediment traps were conducted during a cruise on RRS Charles Darwin to the NW coast of Spain to study the vertical flux and composition of settling biogenic matter. The cruise was split into two legs corresponding to (i) a period of increased production following an upwelling event on the continental shelf (3–10 August 1998) and (ii) an evolution of a cold water filament originating from the upwelled water off the shelf (14–19 August). The export of particulate organic carbon (POC) from the upper layer (0–60m) on the shelf was 90–240mgC.m−2.d−1 and off the shelf was 60–180mgC.m−2.d−1. Off shelf the POC flux at 200m was 50–60mg.m−2.d−1. A modest sedimentation of diatoms (15–30mgC.m−2.d−1) after the upwelling was associated with increased vertical flux of chlorophyll a (1.8–2.1mg.m−2.d−1) and a decrease of the POC:PON molar ratio of the settled material from 9 to 6.4. Most of the pico-, nano-, and microplankton in the settled material were flagellates; diatoms were significant during the on shelf and dinoflagellates during the off shelf leg. Off shelf, the exponential attenuation of POC flux indicated a strong retention capacity of the plankton community between 40 and 75m. POC:PON ratio of the settled particulate matter decreased with depth and the relative portion of flagellates increased, suggesting a novel, flagellate and aggregate mediated particulate flux in these waters. Export of POC from the euphotic layer comprised 14–26% of the integrated primary production per day during the on shelf leg and 25–42% during the off shelf leg, which characterises the importance of sedimentation in the organic carbon budget of these waters. 相似文献
542.
Summary The correlation between the sunspot cycle and the sporadicE-layer ionization is investigated at middle latitudes. Higher mean values off
0Es occur generally with higher sunspot numbers. Some evidence for a phase-shift between long term time-variation in sunspot numbers andf
0Es is obtained. The solar cycle variation ofEs is somewhat larger over the Far East. Regarding the behaviour of the time-development ofEs events in diurnal variation, an interpretation is proposed. 相似文献
543.
Summary The lunar semidiurnal variation of ionospheric absorption at Freiburg and of thef
0
F2 at, Genova, Freiburg and Léopoldville has been deduced. The results are compared with those obtained by other Authors. Magnetic dip, rather than geomagnetic latitude, is found to be a parameter controlling the morphology of the lunar semidiurnal variation of theF2 layer. Finally, a graphical representation of the amplitude of lunar semidiurnal variation off
0
F2 as function of the magnetic dip is also given.
This research was supported by a grant from the Committee on Lunar Variation (IAGA). The paper has been presented at the XII-Assembly of the I.G.G.U. in Helsinki (July–August 1960). 相似文献
Riassunto Viene determinata la variazione lunare semidiurna dell'assorbimento ionosferico per Friburgo e della frequenza critica dello stratoF2 per Genova, Friburgo, Léopoldville. I risultati sono confrontati con quelli ottenuti da altri Autori per varie stazioni situate in diverse parti del globo. In particolare si trova che la inclinazione magnetica, meglio della latitudine geomagnetica, è il parametro che regola la morfologia della variazione lunare inF2. Infine si dà una rappresentazione grafica dell'ampiezza della variazione lunare dellaf 0 F2 come funzione dell'inclinazione magnetica.
This research was supported by a grant from the Committee on Lunar Variation (IAGA). The paper has been presented at the XII-Assembly of the I.G.G.U. in Helsinki (July–August 1960). 相似文献
544.
Lev L. Petrov Yuri N. Kornakov Irina la. Korotaeva Elena A. Anchutina Luidmila A. Persikova Vera E. Susloparova Irina N. Fedorova Viktor A. Shibanov 《Geostandards and Geoanalytical Research》2004,28(1):89-102
This paper describes the creation of two new reference samples of black shale, SCHS-1 and SLg-1, collected in the Bodaibo Region of Irkutsk District (Siberia, Russia). These samples have been developed as State Standard Samples to meet the requirements of Russia's Normative Documents, so that they can be recognised by the Russian State Certification Agency and included on the State Register of certified reference materials. SCHS-1 was produced from shale of the Khomolkho suite; SLg-1 represents the average composition of the Sukhoy Log gold deposit (within Au mineralisation). The homogeneity was assessed by applying the concept of potential inhomogeneity, and the inhomogeneity uncertainties (σinhom ) for the indicator elements that were estimated experimentally by silicate XRF analysis. It was found that a majority of the indicator elements was characterised by σinhom /Δp < 1/8 (Δp is the permissible certification uncertainty), and so σinhom was neglected for the indicator elements and all other elements that were included in their respective group. The value of σinhom calculated for Fe (σinhom,Fe /Δp > 1 /8) was taken into consideration for the noble metals and their associated elements (e.g., Ag, As, Au, etc.). More than fifty laboratories (thirty-seven from Russia) were involved in the interlaboratory experiment (ILE) to analyse these reference samples. The data obtained from the ILE allowed SCHS-1 and SLg-1 to be certified for, fifty-one and forty-three elements, respectively, as State Standard Samples. 相似文献
545.
546.
547.
Luis Jiménez-Benito Angeles Díaz Roberto Terlevich Elena Terlevich 《Astrophysics and Space Science》1998,263(1-4):111-114
We have analyzed high signal-to-noise spectra of 10 active galaxies in order to investigate the stellar populations of these
objects and the kinematics of the gas and stars in their nuclei.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
548.
Palaeomagnetic and geochronological measurements have been carried out on the late Pleistocene basaltic–andesitic unit of Monte Chirica–Costa Rasa, on the island of Lipari (Aeolian Archipelago). The lava flow sequence is about 10 m thick and has been sampled in detail. Magnetic properties are rather uniform; Curie temperatures of 540° to 580 °C, and the saturation IRM reached at applied values of 0.1 T point to titanomagnetite as the main magnetization carrier. Thermal and AF demagnetization have shown the presence of secondary magnetization components. These were removed mostly at 450°–500 °C or 20–30 mT, indicating a highly stable ChRM with directions from transitional to reverse. Where a ChRM could not be isolated by application of the demagnetization techniques, the converging remagnetization circles method gave a mean ChRM value fully comparable with that obtained from other methods. 40 Ar/39 Ar determinations were performed on two lava flows, in the lower and upper parts of the sequence. The former shows a transitional ChRM direction and a whole-rock age of 157±12 ka, the latter a reverse direction, a whole-rock age of 143±17 ka and a ground-mass age of 128±23 ka. The radiometric data and the reconstructed stratigraphy, which indicate ages of 150±10 ka and 104±3.5 ka, respectively, for the volcanic units at the bottom and top of the Monte Chirica–Costa Rasa unit, suggest that the reverse directions recorded in Lipari are related to the Blake event. 相似文献
549.
Elena Terlevich Angeles I. Díaz Roberto Terlevich 《Astrophysics and Space Science》1989,157(1-2):15-21
The IR Caii triplet at 8498, 8542, 8662 Å, relatively easy to observe and measure and free from atmospheric absorption bands, is a powerful tool for the study of the stellar populations in galaxies, provided that we can understand its behaviour with the stellar parameters: effective temperature, surface gravity and metal content. We present here the results of CCD spectroscopic observations for a sample of 86 stars covering a wide range in luminosity, effective temperature and metallicity (from subdwarfs to supergiants and –2.70[F3/H]0.43), in order to establish the dependence of the IR Caii triplet on stellar atmosphere parameters. We do not confirm previous results giving the main dependence on surface gravity. We find instead a bi-parametric dependence on metallicity and surface gravity, and no dependence on effective temperature. 相似文献
550.
Flooding mine tailings to limit the oxidation of sulfides provides a habitat for aquatic organisms, such as plants, plankton,
insects, and fish, which can uptake metals and, thus, threats for local ecosystems and influence the cycling of elements in
biogeocenosis. An aquatic ecosystem developed naturally in sulphide tailing ponds containing cyanidation wastes of the Salair
ore-refining plant (SORP), Russia, was studied. The objectives of this research were to: (i) reveal the level of contamination
of living organisms in the tailing ponds compared to a natural control site and (ii) calculate the weight of metals in aquatic
biomass to estimate the amount of metals transferring from the tailing ponds into the biogechemical cycle. The concentration
of Cu, Zn, Cd, and Pb in the sediments of the tailing ponds is significantly higher than from the control site. Concentrations
of Cu, Zn, Cd, and Pb in plant shoots were significantly higher than in the control and accumulated mainly in cell envelopes
and membranes. The concentration of Pb in fish liver and eggs were 41 and 7.5 times higher, respectively, than maximum allowable
concentrations.
The biomass distribution between producers and consumers of the tailing pond ecosystem is similar to those of natural pond
ecosystems. However, the weights of Cu, Zn, Cd, and Pb in all trophic levels per hectare of the tailing pond are orders of
magnitude higher than those for Lake Baikal. The largest portion of metal circulates within the ecosystem of the Dyukov Ravine
Pond with a maximum of 5 to 13% of this amount transferred into the surrounding environment through the food chains. 相似文献