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41.
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Recent developments for estimating activity coefficients of electrolytes both in pure and multicomponent aqueous solutions are reviewed with good success generally attained up to saturation. Examples are presented to illustrate applications of these methods in calculating ion concentrations, vapor pressures, and solubility limits, for some problems encountered in hydrometallurgy. 相似文献
43.
Chemical partitioning data are of fundamental interest to exploration geochemists. This paper is one of the few studies which has investigated the relative proportions of the rare elements in various soil extracts. The dispersion of trace elements from weathering pegmatites in Powhatan Country, Virginia, was found to be restricted to the immediate vicinity of the pegmatites. A sequential extraction procedure was used to measure the distribution of Be, La, Nb, Sn, U, Li, and Ni,among the following fractions of the B soil horizons: exchangeable, Fe and Mn oxyhydroxide, residual, and aqua regia digestion. The elements Sn, Be, Li, and U were found to be associated with soils over the complex Herbb No. 2 pegmatite, whereas La and Ni were generally associated with the background soils.A geochemical exploration model was developed using stepwise discriminant function analysis to determine the combination of elements and soil extracts that best differentiates between complex pegmatitic, simple pegmatitic, and background soils. Log-transformed aqua regia extract concentrations of Sn, La, U, and Li were the most effective variables when used to separate complex pegmatitic from simple pegmatitic soils. 相似文献
44.
P.TEILHARD DE CHARDIN 《地质学报》1926,(Z1)
During the summer of 1923, we were so lucky F. Licent and myself as to get, in three different places, the first records of the palaeolithic Man in China. 相似文献
45.
This paper offers a preliminary statement of the results of investigations carried out in the South Sangkanho basin, in the mountains some 80 miles to the NW of Peking. Important fossiliferous deposits found in this area throw light on the conditions ruling in N. China during the transition from Pliocene 相似文献
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Twenty seven geochemical reference samples have been analysed for cadmium using the stable isotope dilution technique. These include four USGS, one NBS, five CRPG, eleven ANRT and six NIMROC samples. Each sample has been analysed at least in duplicate.
The four USGS samples have previously been measured in this laboratory by Rosman and De Laeter, but the present results are believed to be more accurate than the earlier data. Our results for the other twenty three samples are much lower than most of the published data. There is also evidence of cadmium inhomogeneities in some of the samples. 相似文献
The four USGS samples have previously been measured in this laboratory by Rosman and De Laeter, but the present results are believed to be more accurate than the earlier data. Our results for the other twenty three samples are much lower than most of the published data. There is also evidence of cadmium inhomogeneities in some of the samples. 相似文献
48.
Mark J. Sier Wil Roebroeks Corrie C. Bakels Enrico Brühl Dimitri De Loecker Norbert Hesse Lutz Kindler Thomas Laurat Herman J. Mücher Kirsty E.H. Penkman Douwe J.J. van Hinsbergen 《Quaternary Research》2011,75(1):213-218
An interdisciplinary study of a small sedimentary basin at Neumark Nord 2 (NN2), Germany, has yielded a high-resolution record of the palaeomagnetic Blake Event, which we are able to place at the early part of the last interglacial pollen sequence documented from the same section. We use this data to calculate the duration of this stratigraphically important event at 3400 ± 350 yr. More importantly, the Neumark Nord 2 data enables precise terrestrial-marine correlation for the Eemian stage in central Europe. This shows a remarkably large time lag of ca. 5000 yr between the MIS 5e ‘peak’ in the marine record and the start of the last interglacial in this region. 相似文献
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