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891.
Ahmet Ruhi Mermut 《山地科学学报》2009,(2):I0002-I0002
Soils, the Earth's Critical Zone, play a vital and fundamental role in the Earth's terrain eco- environment system and human life. Although the concepts of soil/quality and sustainable development have been introduced for decades, we are still failing to understand how well soils function and they need tobe cared and protected. We have been increasingly witnessing and becoming the victim of shrinking forests, 相似文献
892.
A complex study of the influence of various environmental factors on the rate of the oxygen (MO
2), ammonium (MNH
4), and phosphate (MPO
4) metabolism in Ahnfeltia tobuchiensis has been carried out in situ in the Izmena Bay of Kunashir Island. The following environmental factors have been included
into the investigation: the photosynthetically active radiation (PAR); the ammonium (NH4); the phosphate (PO4); and the tissue content of carbon (C), nitrogen (N), phosphorus (P), and chlorophyll a (Chl). The population of agar-containing seaweed A. tobuchiensis forms a layer with a thickness up to 0.5 m, which occupies about 23.3 km2; the population’s biomass is equal to 125000 tons. The quantitative assessment of the organic matter production and nutrient
consumption during the oxygen metabolism (MO
2) has been carried out for the whole population. It has been shown that the daily rate depends on the PAR intensity, the seawater
concentrations of PO4 and NH4, and the tissue content of N and P (r
2 = 0.78, p < 0.001). The daily NH4 consumption averages 0.21 μmol/(gDW h) and depends on the NH4 and O2 concentrations in the seawater and on the C and Chl a content in the algal tissues (r
2 = 0.64, p < 0.001). The daily PO4 consumption averages 0.01 μmol/(gDW h) and depends on the NH4 concentration in the seawater and on the P content in the algal tissues (r
2 = 0.40, p < 0.001). 相似文献
893.
Sh. B. Akhmedov G. B. Gelfreikh F. Fürstenberg J. Hildebrandt A. Krüger 《Solar physics》1983,88(1-2):103-108
Model calculations of the S-component are compared with observations of the RATAN-600 telescope at five discrete microwave frequencies referring to active region McMath No. 15974 on May 1, 1979. The spectral variations of source diameter, flux density, and degree of polarization are used to derive the height scale of the magnetic field in accordance with a magnetic dipole distribution under the assumption of advanced temperature and electron density distributions according to most recent EUV observations. 相似文献
894.
High resolution electric field and particle data, obtained by the S23L1 rocket crossing over a discrete prebreakup arc in January 1979, are studied in coordination with ground observations (Scandinavian Magnetometer Array—SMA, TV and all-sky cameras) in order to clarify the electrodynamics of the arc and its surroundings. Height-integrated conductivities have been calculated from the particle data, including the ionization effects of precipitating protons and assuming a steady state balance between ion production and recombination losses. High resolution optical information of arc location relative to the rocket permitted a check of the validity of this assumption for each flux tube passed by the rocket. Another check was provided by a comparison between calculated (equilibrium values) and observed electron densities along the rocket trajectory. A way to compensate for the finite precipitation time when calculating the electron densities is outlined. The height-integrated HalI-Pedersen conductivity ratio is typically 1.4 within the arc and about 1 at the arc edges, indicative of a relatively softer energy spectrum there. The height-integrated conductivities combined with the DC electric field measurements permitted calculation of the horizontal ionospheric current vectors (J⊥), Birkeland currents (from div J⊥) and energy dissipation through Joule heating (ΣpE2). An eastward current of typically 1 A m?1 was found to be concentrated mainly to the arc region and equatorward of it. A comparison has been made with the equivalent current system deduced from ground based magnetometer data (SMA) showing a generally good agreement with the rocket results. An intense Pedersen current peak (1.2 A m?1) was found at the southern arc edge. This edge constituted a division line between a very intense (> 10 μA m?1) and localized (~ 6 km) downward current sheet to the south, probably carried by upward flowing cold ionospheric electrons and a more extended upward current sheet (> 10 μA m?2) over the arc carried by measured precipitating electrons. Joule and particle heating across the arc were anticorrelated, consistent with the findings of Evans et al. (1977) with a total value of about 100mW m?2. 相似文献
895.
S. L. Bridle I. Zehavi A. Dekel O. Lahav M. P. Hobson A. N. Lasenby 《Monthly notices of the Royal Astronomical Society》2001,321(2):333-340
We compare and combine likelihood functions of the cosmological parameters Ωm , h and σ 8 , from peculiar velocities, cosmic microwave background (CMB) and type Ia supernovae. These three data sets directly probe the mass in the Universe, without the need to relate the galaxy distribution to the underlying mass via a 'biasing' relation. We include the recent results from the CMB experiments BOOMERANG and MAXIMA-1. Our analysis assumes a flat Λ cold dark matter (ΛCDM) cosmology with a scale-invariant adiabatic initial power spectrum and baryonic fraction as inferred from big-bang nucleosynthesis. We find that all three data sets agree well, overlapping significantly at the 2 σ level. This therefore justifies a joint analysis, in which we find a joint best-fitting point and 95 per cent confidence limits of (0.17,0.39), (0.64,0.86) and (0.98,1.37). In terms of the natural parameter combinations for these data (0.40,0.73), (0.16,0.27). Also for the best-fitting point, and the age of the Universe is 13.2 Gyr. 相似文献
896.
897.
Izmailov I. S. Shakht N. A. Polyakov E. V. Gorshanov D. L. Pogodin M. A. 《Astrophysics》2021,64(2):160-171
Astrophysics - This paper is a continuation of our earlier work devoted to determining the orbit and mass of the star 61 Cyg and the changes in the photometric characteristics of its components.... 相似文献
898.
Solar System Research - The paper presents the results of studying the dynamic structure of near-Earth orbital space in the regions of orbital resonances 1 : 4, 1 : 6, and 1 : 8 with the speed of... 相似文献
899.
Slyuta E. N. Vysochkin V. V. Ivanov V. V. Makovchuk V. Yu. Nazarov A. I. Pogonin V. I. Roskina E. A. Safronov V. V. Tatsiy L. P. 《Solar System Research》2021,55(5):437-445
Solar System Research - The ionization-type cosmic dust detector METEOR-L is being developed for the lunar orbiter Luna-26 and is designed to study the distribution of meteoric bodies in space by... 相似文献
900.
Slyuta E. N. Marov M. Ya. Dunchenko A. G. Makovchuk V. Yu. Morozov O. V. Nazarov A. I. Ivanov V. V. Pogonin V. I. Roskina E. G. Safronov V. V. Kharlov B. N. Tatsiy L. P. 《Solar System Research》2021,55(5):446-466
Solar System Research - The device is being developed for the TERMO-LR experiment on the Luna-27 lunar lander; it is intended for contact geophysical measurements of various properties of the lunar... 相似文献