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951.
本文在研究成都市热岛强度时空分布特征基础上,用灰色理论研究其主要的气象影响因子,得出了定性的规律,为今后定量研究提供依据。 相似文献
952.
The angular distribution of solar flare associated hard X-rays ( 10 keV) is calculated on the assumption that they originate as bremsstrahlung emission of energetic electrons with a power law spectrum. For the cross section the relativistic Sauter formula was used. Supposing the electrons to move in a fixed direction, the X-radiation is considerably anisotropic, especially at high photon energies. Taking into account a magnetic field, the anisotropy decreases with increasing pitch angles of the electrons. The anisotropic angular distribution of solar X-radiation seems to be connected with the centre-to-limb variation of hard X-ray bursts and with the correlation of shortwave fadeouts and geomagnetic crochets to H flares. 相似文献
953.
Weidong Guo Chao Wang Yan Li Liyin Qu Muchen Lang Yongbin Deng Qinglong Liang 《地球科学进展》1986,35(9):933-947
Since 1990s, spectral analysis has become an important technique to characterize the properties of chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) from various aquatic systems and a series of spectral indices have been suggested to trace the sources of DOM and their biogeochemical regulation processes. DOM samples were collected from an aquatic continuum from watershed to deep ocean, i.e. Zhangjiang River and Estuary, Dongshan Bay, Taiwan Strait, Northeast basin of the South China Sea, Luzon Strait and the vertical profile of the Kuroshio region of the West Pacific Ocean. This continuum covered many critical interfaces (land-ocean, shelf-basin, marginal sea basin-open ocean and euphotic and aphotic layer). The spatial distribution and variation of various qualitative and quantitative parameters along the continuum were clearly revealed. Combined with literature review, the sources and sinks of CDOM/FDOM and their inherent regulation processes under significant hydrological and biogeochemical gradient variation were systematically summarized. The geochemical differentiation of the quantitative DOM spectral index in various aquatic systems was discussed. The tracing ability of the qualitative DOM spectral index was commented. The coupling study of soil-river organic matter systems, mechanism of mineralization-related microbial production of CDOM/FDOM, quantified geochemical framework concept and perturbation of global change on CDOM/FDOM dynamics were suggested as future key topics. 相似文献
954.
Willem A. van der Westhuizen Dawid Strydom Aylva E. Schoch Eric A. W. Tordiffe Gerhard J. Beukes 《Mineralium Deposita》1986,21(2):121-128
The mineralized Proterozoic metasediments of Bushmanland are characterized by the presence of ferriferous rocks. This includes banded and unbanded iron formations and various types of gossans. These units are not laterally extensive and occur in different stratigraphic levels. The prevalent minerals in the ferriferous rocks are hematite, magnetite, quartz, garnet, muscovite, biotite and sillimanite, but less common occurrences of graphite, alunite, plumbojarosite, gahnite and dufrenite have been noted. The chemical variation (wt%) is extensive: total Fe2O3 (1.3–93.5), SiO2 (4–93), Al2O3 (0.2–14.0), CaO (0.02–20.7), MnO (0.0–14.3), MgO (0.0–5.7), TiO2 (0.0–4.4), Na2O (0.0–2.0), K2O (0.0–1.5) and P2O5 (0.1–7.0). The preliminary nature of the data set precludes, however, firm conclusions regarding stratigraphic control of the chemical composition. The trace-element contents (ppm) extend over several orders of magnitude: Zn (0–7,000), Ba (0–5,200), Cu (0–1,400), Pb (0–1,070) and Ni (6–540). Collectively, the data indicate that most of the ferriferous rocks represent highly metamorphosed sediments. 相似文献
955.
Par Claude Lang 《Aquatic Sciences - Research Across Boundaries》1986,48(2):230-239
Oligochaete communities (tubificid and lumbriculid worms) were studied between 1982 and 1985 in 23 areas of the mesoeutrophic
Lake Geneva (Switzerland). Species numerically dominant in eutrophic lakes (mostlyPotamothrix hammoniensis), in mesotrophic lakes (mostlyP. vejdovskyi) and in oligotrophic lakes (mostlyStylodrilus heringiamus) constituted 52%, 36% et 12% of the worm communities, respectively (means across the 23 areas). The relative abundance of
eutrophic species increased (15 to 94%) according to depth or to external organic inputs. In this case, the mean biomass (wet
weight) of oligochaetes per area was higher than 15 g·m−2 (up to 210 g). Mesotrophic species decreased (65 to 1%) along the same gradients of depth or of sedimentation. Oligotrophic
species increased (0 to 31%) only in areas where the organic sedimentation was lessened by steep bottom slope and by currents.
Thus, the structure of oligochaete communities reflected the patterns of sedimentation and the trophic state of Lake Geneva.
相似文献
956.
Prof. Dr. Gerhard Zickwolff 《Ocean Dynamics》1986,39(6):264-265
Ohne Zusammenfassung 相似文献
957.
Electron microscopic techniques have been applied to investigate the composition and structure of the non-diamond particles, of submicrometre dimensions, that profusely populate the coat of natural coated diamonds. Energy dispersive X-ray spectroscopic analysis (EDS) has shown phosphorus to be commonly present in this included matter, and in the case of some individual crystallites calcium and phosphorus have been the only elements detected with atomic number greater than 11 (the minimum atomic number detectable in the experiments). The latter inclusions exhibit hexagonal prismatic facets and their electron diffraction pattern corresponds to the apatite structure. Approximate lattice parameter values found were c/a=0.73 with a=9.5 Å. 相似文献
958.
959.
960.
Rainer Wolf Mitsuru Ebihara Gerhard R. Richter Edward Anders 《Geochimica et cosmochimica acta》1983,47(12):2257-2270
We have analyzed by RNAA 25 aubrite and 9 diogenite samples for 13 to 29 siderophile, volatile, and lithophile trace elements. Both meteorite classes show a typically igneous siderophile element pattern, with Ir, Os, Re, Ge more depleted than Au, Ni, Pd, Sb. But aubrites tend to have about 10 × higher abundances (10?3 ? 10 ? 4 × Cl for the first 4 and 10?2?10?3 × Cl for the last 4 siderophiles), apparently reflecting smaller metal/silicate distribution coefficients at lowerf(O2), or less complete segregation of metal. Se is surprisingly abundant in aubrites (up to 0.4 × Cl), but Te is less so (), apparently due to its stronger siderophile character. Other volatiles (Ag, Zn, In, Cd, Bi, T1) show depletions intermediate between lunar dunite and the Earth's mantle.Of 7 aubrites analyzed for REE (Ce, Nd, Eu, Tb, Yb, Lu), 6 are depleted in REE (0.08?0.5 × Cl) and 5 show negative Eu anomalies (the exceptions are Bishopville and Mt. Egerton silicate). This supports an igneous origin, as already noted by Boynton and Schmitt (1972). No samples of the complementary, basaltic and feldspathic rocks have been found thus far, but one of our samples of Khor Temiki dark is a candidate for the basalt. It is 5?7 × enriched in REE and only slightly less so in Rb, Cs, and U. Though shocked and enriched in siderophiles to ~0.05 × Cl, it apparently represents a new meteorite class.Three diogenites analyzed for REE show very diverse patterns, from strongly depleted in light REE for Tatahouine (Ce = 0.01 × Cl) to flat for Garland (~2.5 × Cl). The data confirm the trends found by Fukuokaet al. (1977) as well as their interpretations.Factor analysis shows several parallel groupings for aubrites and diogenites: siderophiles (Re, Ir, Os, Pd, Ge), chalcophiles (Se, Te), volatiles (Ag, In, Tl) and incompatibles (U, REE, and Cs or Rb). But there are some differences for elements such as Ni, Sb, Cd, Bi, Au, and Zn, most of which behave more sensibly in aubrites than in diogenites.Several element pairs that differ greatly in volatility (Cs-U, Ge-Ir) correlate closely in aubrites, in approximately Cl-chondrite proportions. These correlations, and other lines of evidence, suggest strongly that aubrites originated by igneous processes in their parent body, not by direct nebular condensation. The source material may have resembled EL chondrites in oxidation state and depletion of refractories, metal, and volatiles. 相似文献