Surface study of HF- and $\text{HF}\text{H}{}_2\text{SO}{}_4\text{-}\text{treated}$ feldspar using Auger electron spectroscopy     

Dale L. Perry  Leon Tsao  Kenneth A. Gaugler 《Geochimica et cosmochimica acta》1983,47(7):1289-1291

Auger electron spectroscopy has been used to study K-feldspar that has been reacted with both aqueous 10% HF and a 50% mixture of a 10% HF/0.1 N H₂SO₄ solution. In the feldspar/HF system, the resulting feldspar surface was shown to have been fluorinated; depth profiling, using argon ion sputtering, showed the fluorination to have occurred substantially into the mineral bulk. In the feldspar/ $\text{HF}\text{H}{}_2\text{SO}{}_4$ system, the resulting surface contained both fluorine and sulfur. The fluorination had again penetrated into the bulk, but the sulfur could be removed with mild argon ion sputtering. The $\text{Al}\text{F}$ signal ratio was much lower on the feldspar surface treated with the 10% HF/0.1 N H₂SO₄ solution than the feldspar surface treated with the weaker 10% HF acid solution.  相似文献   

A Parametric Approach for Dealing with Compositional Rounded Zeros   总被引：2，自引：0，他引：2  

Javier Palarea-Albaladejo  Josep A. Martín-Fernández  Juan Gómez-García 《Mathematical Geology》2007,39(7):625-645

In this work, a parametric approach for replacing data below the detection limit, also known as rounded zeros, in compositional data sets is proposed. Compositional rounded zeros correspond to small proportions of some whole that cannot be reliably detected by the analytical instruments under given operating conditions. This kind of zeros appear frequently in the data collection process in geosciences. They must be treated in an adequate way before some multivariate analysis can be applied. Our procedure results from a modification of the Expectation-Maximization (EM) algorithm and is based on the additive log-ratio transformation. Its coherence with the nature of compositional data and with basic operations in the simplex sample space is checked. Using real data sets, we find that this approach improves other parametric and non-parametric techniques for compositional rounded zeros.  相似文献   

NO2 total column evolution during the 1989 spring at Antarctica Peninsula     

Manuel Gil  Javier Cacho 《Journal of Atmospheric Chemistry》1992,15(2):187-200

Ground-based visible differential absorption spectrometry during twilight has been used for NO₂ total column observations at the Antarctica Peninsula, Marambio Base (64S, 56W), during the austral spring of 1989 (9 September to 25 November).Results show moderate NO₂ vertical column levels of 1.5 to 2.5×10¹⁵ molec cm^-2 in the morning and 2 to 3×10¹⁵ molec cm^-2 in the evening until middle October, highly modulated by planetary wave activity. From that date until the end of the period, a steady increase occurs which is associated with the rising of lower stratosphere temperature as the vortex weakens, reaching values of 5×10¹⁵ molec cm^-2 in late November, with small a.m.-p.m. differences. NO₂ is found to be positively correlated to both total ozone and 50 hPa temperature during the entire spring. However, when analyzing the departures from linear trends, a highly negative correlation has been observed from day 301 onwards.  相似文献   

On the variation of the etesians within the sunspot cycle     

Prof. Dr. Leon N. Carapiperis 《Pure and Applied Geophysics》1960,46(1):190-192

Summary The variation of the Etesians within the sunspot cycle was examined according to observations made at the Athens Observatory during the period 1893–1958. This was made by the actual numbers of the Etesians days and the sunspots as by means of the smoothed values of the above elements through the formula (a+2b+c): 4. It was found that there is a single oscillation of the Etesians within the sunspot cycle and also that the correlation between sunspots and Etesians is rather high.

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Résumé Dans cette étude est examinée la variation des Etésiens pendant le cycle des taches solaires basée sur les observations faites à l'Observatoire d'Athènes durant la période 1893–1958. Dans ce but ont été considerés d'une part les jours réels des Etésiens et les nombres des taches solaires et d'autre les valeurs de ces éléments calculées par la formule (a+2b+c): 4. Il a été constaté que la fréquence des Etésiens présente une simple variation pendant le cycle solaire et qu'il y a une assez grande corrélation entre les taches solaires et les Etésiens.

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Trends in the Mediterranean rainfall     

Leon N. Carapiperis 《Pure and Applied Geophysics》1960,47(1):204-210

Summary The trends appearing in the annual rainfall of the 14 selected coastal and island stations of the Mediterranean were invetigated by running 30-year averages. The periods used as well as the standard deviation, the average variability and the coefficient of variation of the annual rainfall are given for each of the 14 stations. It was found that in the majority of the stations upward and downward trends in the annual rainfall appeared but in a few only stations these trends coincide in the same intervals. A relative similarity appeared in the stations of Marseille-Trieste, Malta-Tunis, Gibraltar-Rome, Nicosia-Limassol and Beyrut-Alexandria. By examination of the three more important maxima and minima in the course of rainfall it was observed that many of them coincide simultaneously at about the same time in the different stations and also that these coincidences occurred near the maximum or minimum of sunspots.  相似文献   

The solar activity and the summer rainfall in the mediterranean     

Prof. Dr. Leon N. Carapiperis 《Pure and Applied Geophysics》1954,27(1):174-178

Summary This study deals with the influence of sunspots on the summer rainfall of 30 selected Stations of the Mediterranean, having records covering at least 4 cycles of sunspots. — It was found that the minimum of summer rainfall occurs near the maximum of sunspots and the maximum of rainfall in the beginning or at the end of sunspots cycle. — The variation of summer rainfall during the sunspots cycle presents four typesA: simple oscillation,B andC: double oscillation andD: triple oscillation.

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Résumé Cette étude s'occupe de l'influence des taches solaires sur la pluie estivale des 30 Stations de la Mediterranée, choisies parmi celles qui couvrent au moins 4 cycles des taches solaires. — On a trouvé que le minimum des pluies estivales a lieu près du maximum des taches solaires et que le maximum des pluies aussi a lieu au commencement ou à la fin du cycle de l'activité solaire. — La variation de la pluie durant le cercle des taches solaires presente 4 typesA: une oscillation simple,B etC une oscillation double etD une oscillation triple.

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On the spells of cold weather over the east Mediterranean during the autumn     

Leon N. Karapiperis 《Theoretical and Applied Climatology》1953,4(4):420-430

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Comparing performance indicators to characterize the water supply to the demands of the Guadiana River basin (Spain)     

Carla Palop-Donat  Javier Paredes-Arquiola  Abel Solera  Joaquín Andreu 《水文科学杂志》2020,65(7):1060-1074

ABSTRACT

Water indicators and indices are useful tools to assess river basin performance, that is, to measure whether the basin operates satisfactorily under a wide range of possible future demands and hydrological conditions. Spanish regulations assess the performance of water demands by using reliability indicators (RIs), established by law in 2008. This article raises the possibility of updating RIs by comparing them with sustainability indicators (SIs). SIs are widely used for the assessment of river basin performance and several policy scenarios. We applied a water allocation model to the Guadiana River basin in Spain to compare indicators under three scenarios. The study was framed within the science of socio-hydrology, combining the physical environment of a water system with its influence on social aspects. SIs gave better results than RIs when comparing future scenarios. We also propose the introduction of a vulnerability indicator into Spanish regulations.  相似文献   

Generation of complete theoretical seismograms for SH—     

Keith Nakanishi  Fred Schwab  Leon Knopoff 《Geophysical Journal International》1977,48(3):525-530

Summary. We report the initial results of our attempts to obtain theoretical seismograms for direct comparison with the experimental time series obtained with the long-period instruments of the WWSSN. The entire theoretical seismogram, including both body waves and surface waves, can be generated for a spherical, anelastic earth by simple inverse Fourier transformation of the sum of the propagating fundamental and higher-mode surface waves. The key to success in reproducing the WWSSN records involves the number of modes, and the minimum period used in these computations; here we use eight modes and a minimum period of 2 s. Efficient computational algorithms make it possible to handle up to 2000 frequency points for each mode; approximately 200 layers are used to model the radial heterogeneity of the earth; attenuation is treated exactly. Examples are given of the SH theoretical seismograms resulting from dislocation sources buried at various depths in the Earth.  相似文献   

Heavy metals in molluscs from the Basque Coast (Northern Spain): results from an 11-year monitoring programme   总被引：1，自引：0，他引：1  

Franco J  Borja A  Solaun O  Pérez V 《Marine pollution bulletin》2002,44(9):973-976

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