Gamma-ray bursts from the first stars: neutrino signals     

Raffaella Schneider  Dafne Guetta  rea Ferrara 《Monthly notices of the Royal Astronomical Society》2002,334(1):173-181

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Upper mantle rocks from basalts of the northern Hessian depression (NW Germany)     

J. Oehm  A. Schneider  K. H. Wedepohl 《Mineralogy and Petrology》1983,32(1):25-48

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Geochemistry of modern seawater and brines from salt pans: Main components and bromine distribution     

Albert Günter Herrmann  Doris Knake  Jürgen Schneider  Heide Peters 《Contributions to Mineralogy and Petrology》1973,40(1):1-24

Seawater at different stages of evaporation from the salt works of Seovlje near Portoro (Yugoslavia) was analyzed geochemically. The seawater there passes through 20 stages of concentration until the first halite crystallizes. All important parameters were determined at all stages: concentrations of Cl, SO₄, Na, K, Ca, Mg, and Br, temperature, pH, Eh, oxygen content and titration alkalinity. With increasing evaporation calcium carbonate crystallizes first followed by calcium sulphate as gypsum and after these halite. All three components crystallize from supersaturated solutions. The pH of the initial seawater is 8.32; it falls abruptly to 6.65 when the first calcium carbonate precipitates. Eh in the original seawater is +393 mv; negative values were found in the halite crystallization pans, which contain an anaerobic mud as a reducing agent. The oxygen content of the solution decreases parallel to the drop in Eh. In the pans in which NaCl crystallizes Eh is zero. Apparently the mud also adsorbs K, as can be inferred from a change in the Mg/K ratio.The bromine partition between crystallizing halite and the brine in the salt pans of Seovlje is discussed with regard to some genetic problems of marine salt deposits. In the conditions in the salt pans the bromine partition coefficient at the beginning of NaCl crystallization from seawater—expressed as b=wt.-% Br (mineral)/wt.-% Br (solution)—is 0.12 to 0.14 or—expressed as D=Br/Cl(mineral)/Br/Cl(solution)—0.030 to 0.034 at temperatures between 33° C and 42° C. The conclusion is that a Br content of about 60 to 75 ppm is to be expected for the first halite that crystallizes from evaporating seawater.  相似文献   

The theory of motion of the horizontal pendulum with a Zöllner suspension and some indications for the instrumental design     

Petr Vaníček  Geoffrey W. Lennon  Reviewer M. Schneider  Reviewer L. Skalský 《Studia Geophysica et Geodaetica》1972,16(1):30-50

Summary The aim of this paper is to examine the physical laws which govern the motion of a horizontal pendulum, mounted with the familiar Zöllner suspension geometry and to establish the equations of its motion. It is possible in this process to determine calibration parameters with greater precision and confidence and to demonstrate that procedures based upon period measurement can inherently claim a precision superior to some modern alternatives. Moreover in approaching the problem from a theoretical viewpoint it is possible to pinpoint those features of design which give rise to the troublesome aberrations. This facility makes it possible to comment upon design improvements so that a closer approach may be made to an ideal instrument.  相似文献   

Drought,demography, and destitution: Crisis in the Norte Chico   总被引：1，自引：0，他引：1  

Hans J. Schneider Dr. 《GeoJournal》1982,6(2):111-119

Growing population pressure, limited natural resources, and recurring droughts are thought to be the chief reasons for the socio-economic backwardness in the Norte Chico region of Chile (29 to 33^o S).Droughts occur with rather high statistical frequency; in recent decades they appear to have become even more frequent. Depletion of the already scant forest resources of the area occured during the nineteenth century, when most of the wooden species were used as firewood, charcoal or fuel for settlements, mines ans smelters. Also during that century, forests and shrubs were cut down in order to make room for wheat cultivatio. At the same time as agricultural exploitaion and mining intensified, increasing sheep and goat herding contributed further to the deterioration of the environment.Disputable is the assumption that the cause of the socio-economic depression in the Norte Chico is the population pressure on limited natural resources. Census figures reveal that the region has not been growing as fast as other regions in the country and that outmigration has constituted a constant demographic drain from the area. The cause for this migration has been not so much the environmental deterioration but the perpetuation of land tenure patterns that stress latifundia and minifundia without allowing for the development of independent mid-size agricultural establishments.To a large degree the backwardness of the Norte Chico is to be blamed not so much on the unwise exploitation of the resources but on the persisting patterns of economic exploitation and social structures.  相似文献   

The seismotectonic character of the September 3, 1978, swabian jura earthquake series     

J. Turnovsky  G. Schneider 《Tectonophysics》1982,83(3-4)

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Climatic impact assessment in the CO2 context — An editorial     

H. Stephen Schneider 《Climatic change》1981,3(4):345-346

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Relativistic effects in the motion of artificial satellites: The oblateness of the central body I     

M. Soffel  R. Wirrer  J. Schastok  H. Ruder  M. Schneider 《Celestial Mechanics and Dynamical Astronomy》1987,42(1-4):81-89

The motion of artificial satellites in the gravitational field of an oblate body is discussed in the parametrized-post-Newtonian (PPN) framework with parameters and . Analytical expressions for first order post-Newtonian short periodic, long periodic and secular perturbations of orbital elements are given.  相似文献   

In Situ Trace Gas and Particle Measurements in the Summer Lower Stratosphere during STREAM II: Implications for O3 Production     

A. Bregman  F. Arnold  V. Bürger  H. Fisher  J. Lelieveld  B. A. Scheeren  J. Schneider  P. C. Siegmund  J. Ström  A. Waibel  W. M. F. Wauben 《Journal of Atmospheric Chemistry》1997,26(3):275-310

In situ aircraft measurements of O₃, CO,HNO₃, and aerosol particles are presented,performed over the North Sea region in the summerlower stratosphere during the STREAM II campaign(Stratosphere Troposphere Experiments by AircraftMeasurements) in July 1994. Occasionally, high COconcentrations of 200-300 pbbv were measured in thelowermost stratosphere, together with relatively highHNO₃ concentrations up to 1.6 ppbv. The particlenumber concentration (at standard pressure andtemperature) between 0.018-1 m decreased acrossthe tropopause, from >1000 cm^-3 in the uppertroposphere to <500 cm^-3 in the lowermoststratosphere. Since the CO sources are found in thetroposphere, the elevated CO mixing ratios areattributed to mixing of polluted tropospheric air intothe lowermost extratropical stratosphere. Further wehave used a chemical model to illustrate that nitrogenoxide reservoir species (mainly HNO₃) determinethe availability of NO_x (=NO + NO₂) andtherefore largely control the total net O₃production in the lower kilometers of thestratosphere. Model simulations, applying additionalNO_x perturbations from aircraft, show that theO₃ production efficiency of NO_x is smallerthan previously assumed, under conditions withrelatively high HNO₃ mixing ratios, as observedduring STREAM II. The model simulations furthersuggest a relatively high O₃ productionefficiency from CO oxidation, as a result of therelatively high ambient HNO₃ and NO_xconcentrations, implying that upward transport of COrich air enhances O₃ production in the lowermoststratosphere. Analysis of the measurements and themodel calculations suggest that the lowermoststratosphere is a transition region in which thechemistry deviates from both the upper troposphere andlower stratosphere.  相似文献   

Parameterization of spectral distributions for pion and kaon production in proton-proton collisions     

Schneider JP  Norbury JW  Cucinotta FA 《The Astrophysical journal. Supplement series》1995,97(2):571-574

Accurate semi-empirical parameterizations of the energy-differential cross sections for charged pion and kaon production from proton-proton collisions are presented at energies relevant to cosmic rays. The parameterizations depend on the outgoing meson momentum and also the proton energy, and are able to be reduced to very simple analytical formulas suitable for cosmic-ray transport.  相似文献