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411.
M. Grasserbauer S. Paleczek J. Rendl A. Kasper H. Puxbaum 《Fresenius' Journal of Analytical Chemistry》1994,350(7-9):431-439
Background measurements at the high alpine station of the Sonnblick (altitude 3106 m) are reported. For a period of 13 months samples have been collected during 4 campaigns of 1–2 weeks duration each and analysed for their ionic and elemental composition, pH and conductivity. These samples were aerosols collected with filters, cloud water and precipitation. The samples were mainly analysed with ion chromatography (IC) and atomic absorption spectrometry (AAS). Analysis proved to be difficult due to the low amounts of aerosols collected and the low concentrations of components in cloud water and wet precipitation. Also major problems arose in sampling due to the extreme climatic conditions. The analytical techniques, particularly those for sampling the materials, are critically evaluated and results on pollutant levels, their variation with time and the distribution of the components between the gaseous and liquid phases are presented.Abbreviations ET-AAS
Electrothermal Atomic Absorption Spectrometry
- F-AAS
Flame Atomic Absorption Spectrometry
- FIA
Flow Injection Analysis
- IC
Ion Chromatography
Dedicated to Prof. Dr. Dieter Klockow on the occasion of his 60th birthday 相似文献
412.
U. Kasper 《Annalen der Physik》1979,491(2):135-147
Subject is considered on the level of classical field theory. We start from some aspects of the theory of ferromagnets. Their counterpart in classical field theory is pointed out using the over simplified model of a selfinteracting scalar field. The ground state (“vacuum expection value”) of the scalar field is interpreted as cosmic background field, which can be considered as constant for local physical phenomena. In practice, however, it is a function of the age of universe. Which kind of function it could be is suggested by a discussion of the cosmic variability of Eddington's number γ = 1040, which refers to Dirac's consideration of this problem. But contrary to Dirac's assumption that atomic quantities are constant, we suppose that the inertial mass of elementary particles is a function of the age of universe. The cosmic gravitational field is described by other equations than the gravitational field created by local matter distributions. The field equations for the local gravitational field we start from reduce to Einstein's equations, if we neglect the possible influence of the universe on local phenomena. In case that the cosmic matter is homogeneously and isotropically distributed, the field equations for the cosmic gravitational field permit only such a time dependent solution the three-spaces of which are linearly expanding and spherically closed. The different field equations for cosmic and local gravitational fields are considered approximations of more fundamental field equations which approximately split into two sets of equations, if it is possible to contrast local physical systems with the universe. The described cosmological model taken as a basis, the inertial mass of elementary particles becomes a function of the matter density creating the cosmic gravitational field. This could be considered as, at least, partly realisation of Mach's idea concerning the origin of inertia. Starting from the interpretation of the ground state (vacuum expection value) as a function of a certain cosmic background field, more realistic gage field models could give the following picture of cosmic development: In the far past there was a state of the universe characterized by enormous contraction of matter. In this stage of development, it was impossible to contrast particles with the universe. Matter expands and it becomes possible to contrast certain physical systems with the universe. But the ground state is such a symmetric one that only fields with vanishing rest mass can be contrasted with the universe (ferromagnet above Curie temperature). With further expansion of the universe the ground state will lose certain symmetry properties. By this it becomes possible that you get the impression there are particles with nonvanishing rest mass (ferromagnet below Curie temperature). Finally, the influence of the universe on local physical systems goes to zero with further expansion. Especially, this means the inertial mass of elementary particles goes to zero, too (Curie temperature of ferromagnetic material goes to zero with cosmic expansion). 相似文献
413.
Craig S. Lage Ward Whaling 《Journal of Quantitative Spectroscopy & Radiative Transfer》1976,16(6):537-542
We have measured branching ratios for all of the known transitions from five levels in Pr+. We use the known mean lifetime of four of these levels to compute transition probabilities for 40 transitions. Five of our stronger lines are seen in the sun. We use the equivalent widths of Moore et al. and the solar model parameters of Righini and Rigutti to compute the photospheric Prabundance: log (NPr/NH) + 12 = 0.66 ± 0.15. This value is a factor of ten lower than the most recent photospheric abundance measurement of Grevesse and Blanquet. The difference arises in part from the new transition probabilities, in part from the equivalent widths. We justify our use of widths from Moore et al. by comparing them with widths measured on the Preliminary Kitt Peak Solar Atlas. 相似文献
414.
Kasper K. S. Andersen Tilman Bauer Jesper Grodal Erik Kjaer Pedersen 《Inventiones Mathematicae》2004,157(1):1-10
We construct a connected finite loop space of rank 66 and dimension 1254 whose rational cohomology is not isomorphic as a graded vector space to the rational cohomology of any compact Lie group, hence providing a counterexample to a classical conjecture. Aided by machine calculation we verify that our counterexample is minimal, i.e., that any finite loop space of rank less than 66 is in fact rationally equivalent to a compact Lie group, extending the classical known bound of 5. Mathematics Subject Classification (2000) Primary: 55P35; Secondary: 55P15, 55R35 相似文献
415.
U. Kasper 《Annalen der Physik》1978,490(1):50-60
We consider a theory in which the global and local space-time properties are described by different laws. One consequence of such a theory is that the only time-dependent cosmological models are such that their homogeneous and isotropic three-spaces are closed. In the framework of this theory the local space-time properties are approximately described bei Einstein's equations, but with Einstein's gravitational coupling number now being a function of the matter density filling the universe. 相似文献
416.
E. Kasper H. J. Herzog H. Kibbel 《Applied Physics A: Materials Science & Processing》1975,8(3):199-205
One-dimensional SiGe superlattices with periods ranging from 100 to 800 Å have been deposited on Si substrates by periodically varying the Ge content of a mixed Si1-x Ge x multilayer structure fromx=0 tox=0.15. The deposition was successful, employing and UHV evaporation technique at a substrate temperature of 750°C fulfilling the four conditions: Single crystal growth, no interdiffusion, two-dimensional growth, and pseudomorphic growth. It is shown that mismatch above 8 · 10?3 favours growth by three-dimensional nucleation. The experimentally determined spacing of misfit dislocations is compared with theoretical results obtained by van der Merwe. The pseudomorphic growth behaviour of layers thinner than a critical thickness could be confirmed. 相似文献
417.
John H. Birely Jerome V.V. Kasper Francis Hai Lane A. Darnton 《Chemical physics letters》1975,31(2):220-224
An upper bound of 6 × 1010 cm3/moles on the rate constant for the reaction of atomic oxygen with vibrationally excited H2 has been deduced from laboratory observations and from detailed computer calculations. From this result it can be shown that no more than 30% of the vibrational energy of H2 is effective in overcoming the activation energy for the O + H2 reaction. 相似文献
418.
R. O. Korob I. M. Cohen M. Lage M. I. Milá 《Journal of Radioanalytical and Nuclear Chemistry》1978,42(1):121-131
A radiochemical procedure developed by the authors for neutron activation analysis of As, Cd, Cu, Sn, and Zn in beef extract
samples is described, based on combined precipitation steps to isolate the elements to be determined. Nuclides are separated
with high degree of purity and good chemical yields. Interferences from threshold reactions are discussed and calculated.
Results are shown for analysis of six samples. 相似文献
419.
Vazquez Troche S García Falcón MS González Amigo S Lage Yusty MA Simal Lozano J 《Talanta》2000,51(6):1069-1076
We have developed a simple method for the determination of the carcinogen Benzo[a]pyrene (BP) in vegetable oils. The method consists of extraction of the vegetable oil in acetonitrile, concentration to dryness in rotary evaporator and redissolution of the residue in hexane. The purification of the hexane extract was on Sep-Pack Silica Plus cartridges, and the determination of the BP in the isolated extract was by HPLC-FL. Detection and quantification limits were 0.23 and 0.32 μg kg−1 of olive oil, respectively. Recovery (>93%) and RSD (<4%) were satisfactory. When applied to 18 oil samples, BP levels varied from not detected to 1.99 μg kg−1. 相似文献
420.