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251.
David P. Kratz Martin G. Mlynczak Christopher J. Mertens Helen Brindley Larry L. Gordley Javier Martin-Torres Ferenc M. Miskolczi David D. Turner 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,90(3-4):323-341
A considerable fraction (>40%) of the outgoing longwave radiation escapes from the Earth's atmosphere-surface system within a region of the spectrum known as the far-infrared (wave-numbers less than 650 cm−1). Dominated by the line and continuum spectral features of the pure rotation band of water vapor, the far-infrared has a strong influence upon the radiative balance of the troposphere, and hence upon the climate of the Earth. Despite the importance of the far-infrared contribution, however, very few spectrally resolved observations have been made of the atmosphere for wave-numbers less than 650 cm−1. The National Aeronautics and Space Administration (NASA), under its Instrument Incubator Program (IIP), is currently developing technology that will enable routine, space-based spectral measurements of the far-infrared. As part of NASA's IIP, the Far-Infrared Spectroscopy of the Troposphere (FIRST) project is developing an instrument that will have the capability of measuring the spectrum over the range from 100 to 1000 cm−1 at a resolution of 0.6 cm−1. To properly analyze the data from the FIRST instrument, accurate radiative transfer models will be required. Unlike the mid-infrared, however, no inter-comparison of codes has been performed for the far-infrared. Thus, in parallel with the development of the FIRST instrument, an investigation has been undertaken to inter-compare radiative transfer models for potential use in the analysis of far-infrared measurements. The initial phase of this investigation has focused upon the inter-comparison of six distinct line-by-line models. The results from this study have demonstrated remarkably good agreement among the models, with differences being of order 0.5%, thereby providing a high measure of confidence in our ability to accurately compute spectral radiances in the far-infrared. 相似文献
252.
Ferenc Vajda Edward Della Torre Martha Pardavi-Horvath 《Journal of magnetism and magnetic materials》1993,120(1-3):289-291
It has been shown that the scalar properties of recording media can be characterized by a moving model that includes reversible and irreversible magnetizing processes. A test of this model for various media is reported in this paper. It is found that the model is capable of calculating accurate major and minor loops. 相似文献
253.
Ferenc Móricz 《Archiv der Mathematik》2006,86(4):375-384
In recent years, the almost sure central limit theorem attracted widespread attention in Probability Theory. It involves the
harmonic (also called logarithmic) averages of a certain numerical sequence formed from a sequence of independent, identically
distributed random variables. Our primary aim is to study the convergence behavior of the sequence of harmonic averages of
a given numerical sequence from the viewpoint of Summability Theory.
Received: 12 May 2005; revised: 1 July 2005 相似文献
254.
255.
Kornl Nagy Alastair B. Ross Laurent B. Fay Alexandre Bourgeois Martin Kussmann 《Rapid communications in mass spectrometry : RCM》2008,22(24):4098-4104
Erythrocyte alkylresorcinols (5‐alkyl‐1,3‐dihydroxybenzenes) are potential biomarkers of wholegrain wheat and rye intake. However, their high‐throughput quantitative analysis by gas chromatography/mass spectrometry (GC/MS) is hindered by the time‐consuming sample preparation and, more importantly, by interfering compounds that still remain after sample cleanup. In the present work we describe a gas chromatography/tandem mass spectrometry (GC/MS/MS) method for the rapid and reliable quantification of alkylresorcinols in erythrocyte samples. The performance of the GC/MS/MS method is compared with that of GC/MS. The main characteristics of the method are: lower limits of detection: 2–10 µg/L standard solution; lower limits of quantification: 6–30 µg/L standard solution; linearity coefficients: 0.9611–0.9888; linear ranges: 2–20 µg/L in erythrocytes; and intra‐day precisions (n = 6): 4–13% at endogenous analyte levels in non‐spiked erythrocytes. Tandem mass spectrometry showed greatly improved selectivity over single‐stage mass spectrometry in the case of erythrocyte samples, eliminating all interferences detectable in single‐stage MS and enabling simple peak integration for quantification. Moreover, increased selectivity resulted in GC separation speeded up by a factor of two, allowing the duplicate analysis of over 40 samples per day. This GC/MS/MS method is suggested as an improved alternative to GC/MS for the quantification of alkylresorcinols in erythrocytes for assessing wholegrain wheat and rye intake. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
256.
A general summability method is considered for functions from Herz spaces Kαp,r (?d ). The boundedness of the Hardy–Littlewood maximal operator on Herz spaces is proved in some critical cases. This implies that the maximal operator of the θ ‐means σθ T f is also bounded on the corresponding Herz spaces and σθ T f → f a.e. for all f ∈ K–d /p p,∞ (?d ). Moreover, σθ T f (x) converges to f (x) at each p ‐Lebesgue point of f ∈ K–d /p p,∞ (?d ) if and only if the Fourier transform of θ is in the Herz space Kd /p p ′,1 (?d ). Norm convergence of the θ ‐means is also investigated in Herz spaces. As special cases some results are obtained for weighted Lp spaces. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
257.
Electron-impact ionization cross sections for lithium-like ions have been computed in three variants of the distorted wave approximation. It is found that the inclusion of the electron exchange in the standard form yields the best results, in very good agreement with the experiment and the elaborate calculations of Jakubowicz and Moores. 相似文献
258.
Zusammenfassung Die 3,3-Dimethylnaphthidin-Wasserstoffperoxid-Redoxreaktion wird von Jodid sehr stark katalysiert. Damit kann man bei Anwesenheit von Ameisensäure Jodid selbst in einer Grenzkonzentration von 0,002g/ml nachweisen bzw bestimmen. Dazu eignet sich die Simultankomparationsmethode. Im Konzentrationsbereich von 0,1 bis 0,01g J–/5 ml beträgt der relative Fehler 3%. Ag+, Hg2+ oder Bi3+ dürfen nicht anwesend sein; andere störende Ionen können mit ÄDTA bzw. Weinsäure maskiert werden.
Catalytic detection and determination of traces of iodine by means of the 3,3-dimethylnaphthidine-hydragen peroxide reaction
Summary The 3,3-dimethylnaphthidine-hydrogen peroxide redox reaction is strongly catalysed by iodide. Therefore, if formic acid is present, iodide itself may be detected or determined in a limiting concentration of 0.002g/ml. The simultaneous comparation method is appropriate here. In the concentration region from 0.1 to 0.01g I–/5 ml, the relative error is 3%. Ag+, Hg2+ or Bi3+ may not be present. Other interfering ions can be masked with EDTA or tartaric acid.相似文献
259.
Summary A new type of gas sampling device was constructed to improve the analysis of the gas in halogen lamps. Low levels of gases such as O2, CH4, C2H4 and CH3Br could be determined by the techniques worked out. 相似文献
260.