bluuebunny/crossref_metadata_2025_split huggingface dataset:
Der Mond als Mutterkörper der Bronzit-Chondrite
Authors: Wänke H. 
Published: March 2015

Knowing the cosmic ray exposure ages of a sufficiently large number of meteorites and using the earth as analyser with special assumptions, criteria can be found to distinguish between a lunar or asteroidal origin of meteorites. Several of the following arguments are based on new and unpublished results of rare gas measurements by HINTENBERGER, SCHULTZ und WÄNKE70.
Bronzite-chondrites :
1. Arguments for an origin near the surface of the parent body. a) Porosity of the chondrites 0—20%. b) Many bronzite-chondrites contain light primordial rare gases, originating from the exposure of the single meteorite grains to the solar wind. c) Primordial rare gas content always connected with light-dark structure. d) In the distribution of the cosmic ray exposure ages certain groupings can be distinguished. The age distribution of bronzite-chondrites with light primordial rare gases is identical with the distribution of the cosmic ray exposure ages of all bronzite-chondri-tes. The bronzite-chondrites containing primordial gas therefore are probably coming from the very upper layers, and the other bronzite-chondrites from somewhat deeper layers of their parent body.
2. Arguments for an origin close to the earth’s orbit. a) Bronzite-chondrites with high cosmic ray exposure ages show a slight tendency to fall in the afternoon (noon until midnight) . b) For the bronzite-chondrites, which are morning falls (midnight until noon), diffusion losses of 3He and 4He are higher and more frequent compared to the afternoon falls. The reason for this can be found in a closer approach to the sun of the first ones. Hypersthene-chondrites do not show this effect. c) Bronzite-chondrites with light primordial rare gas content concentrate among the afternoon falls. d) The mean cosmic ray exposure age of the bronzite-chondrites is considerably lower than that of the hypersthene-chondrites.
3. Arguments concerning the size of the parent body. Light primordial rare gas and their connection with light-dark structure indicate a parent body of the size of the moon or a large asteroid.
None of these arguments are strictly conclusive. In some cases they are based on observations, which can only be obtained by using statistical methods. Most of these effects are close to the mean error. Adding, however, all observations together, a lunar origin of the bronzite-chondrites becomes nearly undoubtable. A lunar origin of stone meteorites was in recent times first proposed by URET 3.
Hypersthene-chondrites :
Hypersthene-chondrites with low cosmic ray exposure ages are rare among the morning falls. Their parent body therefore probably has to be found outside the earth’s orbit. Their distribution of the cosmic ray exposure ages may also lead to this conclusion. As proposed by ANDERS 4, the Mars asteroids could possibly be the parent bodies for the hypersthene-chondrites. Mars itself might however be considered also. A lunar origin of the hypersthene-chondrites seems to be completely out of question.
Die Produktionsraten von 36Cl und 39Ar in Metall- und Steinphase des Chondriten Leedey
Authors: Begemann F. , Vilcsek E. , Wänke H. 
Published: March 2015

The production rates of 36Cl and 39Ar by the cosmic radiation on Fe and Ca +K have been determined in the chondrite Leedey. The values of
19.4 atoms/min · kg ≦ PFe (36Cl) ≦ 26.6 atoms/min · kg and PFe (39Ar) = (23.6 ± 1.8) atoms/min · kg are in good agreement with those found in iron meteorites of comparable size. A large contribution of Ca+K to the production of both isotopes is indicated by the ratios
9.2 ≦ PCa + K (36Cl) /PFe (36Cl) ≦ 13.6 and PCa + K (39Ar) /PFe (39Ar) = 12.1 ± 1.6. The bearing of these results on the interpretation of 39Ar-data obtained on other chondrites is being discussed.
Flächengitter in geschmolzenem Zinn und Silber sowie in festem amorphem Selen nach der Fourier-Analyse
Authors: Richter H. , Breitling G. 
Published: March 2015

Die 4 π r [ρ (r) —ρ0] -Kurven von geschmolzenem Sn bei 250° und 750°C zeigen, daß in der Schmelze zwei Strukturen vorkommen, die dichteste Kugelpackung mit r1=3,15 bzw. 3,18 Å (Literaturwert r12=3,16 Å) und die Flächengitter-Struktur mit r1′=3,01 bzw. 3,03 A als Kantenlänge einer quadratischen Gitterzelle. Dabei ist r1′[r1] G=3,02 A, also gleich dem kürzesten Gitterabstand. In der Ag-Schmelze tritt die dichteste Kugelpackung in Form von Flächengittern mit der (111)kub.- bzw. (001) hex.-Ebene als Basis auf. Die Abmessungen der zugehörigen hexagonalen Gitterzelle sind r1=2,94 A und φ=120°. Überraschenderweise zeichnen sich in der 4 π r [ρ (r) — ρ0]-Kurve lediglich die Abstände der Zickzackkette ab, die von den Atomabständen r1=2,94 Å und r1 √3 =5,09 Å gebildet wird. Die Flächengitter-Struktur besteht bei Ag wie bei Sn aus einer quadratischen Gitterzelle, und zwar mit r1′=2,72 Å als Kantenlänge. Danach ist die Ag-Schmelze ein Haufwerk von Flächengittern mit hexagonaler und mit quadratischer Gitterzelle; Gleiches gilt für die Schmelzen von Au, Pb und Tl. Auch in den 4 π r [ρ (r) —ρ0] -Kurven von geschmolzenem Na und Cs bildet sich die Zickzackkette der dichtesten Kugelpackung ab. Die Alkalimetallschmelzen stehen damit dem geschmolzenen Au, Ag, Pb und Tl sehr nahe, weniger dagegen dem geschmolzenen Sn, Ga und Bi.
Die Zickzackkette wird auch bei den festen amorphen Stoffen erhalten. So zeichnet sich in der 4 π r2 [ρ (r) —ρ0] -Kurve von festem amorphem Se die ebene Zickzackkette ab, die sich aus den Gitterabständen [r1] G=2,32 Å und [r3]G=3,69 Å (Bindungswinkel φ=105°) aufbaut. Bei großen Abstandswerten ist selbst hier wegen der Lagestreuung der Atome eine deutliche Abstandsverkürzung wie bei geschmolzenem Au, Ag, Pb und Tl zu beobachten.
Zum Mechanismus der Dotierung von Silicium mit Phosphor bei Anwesenheit einer Oberflächenschicht aus (SiO2)n · P2O5
Authors: Garski Helga 
Published: March 2015

The diffusion of phosphorus into silicon out of gaseous P2O5 is rated by a glassy surface layer of (SiO2) n· P205. The dependence of glass composition and sheet resistance of the diffused layer on P2O5-concentration in the reaction zone is examined at constant diffusion time and temperature. There is no simple linear relation. The results can be explained by a discussion of the phase diagram of SiO2—P2O5.
Even at low doping levels far below the solubility limit only part of all phosphorus in the silicon contributes to electrical conduction. The relative part of inactive phosphorus increases with decreasing resistivity.
Die Atomverteilung im glasigen roten Phosphor
Authors: Krebs H. , Gruber H. U. 
Published: March 2015

Using a BRAGG—BRENTANO camera followed by a bent quartz monochromator the scattering intensities of amorphous red phosphorous were determined and converted into the atomic distribution curve. Radiation of various wavelengths (CuKa, MοKa, AgKa) were used. Each phosphorous atom is surrounded by three nearest neighbours at a distance of 2.24 Å and six others at a distance of 3.48 A. At a distance of 3.48 Å one also finds on the average almost two more atoms with the VAN DER WAALS distance. The bond angle is about 102°. The close range order must be related to that in the lattices of the polyphosphid MePbP14.
An improved procedure for normalization and for the elimination of the COMPTON scattering is given and discussed.
Further Study on Y Transitions in 140Ce
Authors: El-Nesr M. S. , El-Aassar M. R. 
Published: March 2015

A photoline spectrum from the γ rays of energies greater than 200 keV following the decay of 40-hour 140La has been studied using a high resolution double focusing ß-ray spectrometer. The photoelectrons are produced from an uranium radiator of thickness 2.9 mg/cm2. The resulting momentum resolution was 0.3 → 0.8% depending on energy. In addition to γ rays previously reported, we have observed 17 new γ transitions in the energy region of about one MeV to 2.53 MeV. The relative γ-ray intensities have been determined from the external conversion spectrum applying the corrections for the angular dependence of the photo-electric process. Gamma energies and intensities higher than 2.53 MeV have been investigated by means of a scintillation spectrometer using a RiDL-transistorized 400 channel analyzer. A complete set of energy sums was computed in order to survey the possibilities of cascade crossover combinations. Thirteen direct ground state transitions of energies 204.87, 241.95, 993.12, 1597.48, 1973.38, 2026.37, 2350.23, 2371.11, 2410.33, 2530.03, 2900, 3100 and 3471 keV were observed. A few modifications on the previously reported level scheme of 140Ce are proposed after the addition of the 17 new γ rays. Conversion coefficients were obtained by normalizing the ratios of conversion and photon intensities with respect to the 487 keV-E2 transition in 140Ce. From the known internal conversion coefficient of this transition, the absolute K-internal conversion coefficients of the transitions 200.08, 241.95, 273.69, 337.50, 374.81, 400.53 and 875.30 keV were determined to confirm their multipolarities and support spin and parity assignments of the levels 242, 617, 1260, 1323, 2184, 2515, 2585 and 3390 keV.
The absolute K-internal conversion coefficients of the 542.43, 641.41, 752.62, 927.41, 980.19, 1016.20, 1040.31 and 1054.65 keV transitions were measured for the first time. The multipolarity assignments of these transitions were studied on the basis of the conversion coefficients. These measurements together with the previously known assigned levels establish the spins and parities 3-, 0+, 2+, 4+, 2+, and 2+ for the levels 205, 1889, 1973, 2084, 2350 and 2530 keV, respectively. Spin and parity assignments of 1+ and 4- are proposed for the 2900 and 3100 keV excited levels in 140Ce respectively.
Nachlieferung von Elektronen beim Entladungsaufbau in Wasserstoff und Sauerstoff für E/p von 60 bis 3000 Volt/cm Torr
Authors: Schlumbohm H. 
Published: March 2015

By analysing the temporal current shapes of electron avalanches the different secondary ionisation processes occuring in H2- and O2-discharges have been separated and data taken. In hydrogen at E/p < 250 volts/cm Torr secondary electrons are released at the cathode by photons emitted mainly from excited states of the WERNER-bands of the H2-molecule. In oxygen secondary electrons are released both within the gas and at the cathode at E/p < 500 volts/cm Torr by photons from electronic states above the first ionisation level of the O2-molecule, which are excited by single electron collisions.
With increasing E/p additional secondary electrons in hydrogen are produced by positive ions at the cathode, but for E/p > 170 volts/cm Torr the avalanche currents cannot be interpreted by the photon and ion processes thus indicating the action of a third mechanism. The same result was obtained for oxygen at E/p > several 100 volts/cm Torr. This additional process is discussed on the basis of different ion species and a possible action of fast neutral molecules resulting from charge exchange collisions.
Anregung und Dissoziation von Molekülen beim Elektronenbeschuß
Authors: Niehaus Arend 
Published: March 2015

Die beim Elektronenbeschuß von N2, Butan, cis-2-Buten, 1,3-Butadien und Hexan entstehenden neutralen Fragmente wurden ionisiert und massenspektrometrisch nachgewiesen, wobei zwischen Bildung und Nachweis weder Wandstöße noch Stöße mit anderen Molekülen stattfanden. Die Bildungswahrscheinlichkeit der Fragmente als Funktion der Energie, von der Schwellenenergie (DP) bis 100 eV, wird angegeben.
DP für N aus N2 ist (9,6 ± 0,5) eV, d. h. für die Dissoziation an der Schwelle ist der Prozeß N2→N2*→2 N (4S) verantwortlich. Die DP-Werte für Fragmente aus Butan und Hexan genügen der Beziehung: DP=E1+D*, wobei E1 die Energie des 1. Elektronenniveaus und D* die jeweilige Bindungsenergie in diesem Zustand (E1 ≈ 8 eV) ist. Die DP-Werte von cis-2-Buten und 1,3-Butadien liegen tiefer und genügen der gleichen Beziehung mit E1=2 -4 e V.
Das Verhältnis (γ) von neutralen Zerfällen zur Ionenbildung liegt bei allen untersuchten Substanzen in der Nähe von 1. Der größte Teil der neutralen Zerfälle erfolgt durch Anregung von „superexcited states“.
Der Nachweis von innerer Anregung durch Messung eines erniedrigten Ionisierungspotentials gelang nur bei dem Bruchstück H2.
The Electric Conductivity of Molten (Na—Tl)NO3 Mixtures
Authors: Wagner Vittoriano , Forcheri Sandro 
Published: March 2015

Electrical conductivities and densities of molten (Na—Tl)NO3 mixtures have been measured in the temperature range between 192°C and 400°C.
At all compositions the specific conductivities appear to be linear functions of the temperature. While the equivalent conductivities of the mixtures deviate negatively from additivity, the apparent activation energies ΔΕ (from the relation Λ =Λ0 · exp(—ΔE/R T) exhibit positive deviations from additivity.
This behavior is similar to that of other univalent binary systems with a common anion and seems to indicate that the polarization of the nitrate ion due to different cation sizes is the main cause of the additional hindrance to the electrical transport in mixtures.
Photodissoziationen zu elektronisch angeregten Bruchstücken von H2, H2O und NH3 im extremen Vakuum-UV. II
Authors: Beyer K. D. , Welge K. H. 
Published: March 2015

Im fernen Vakuum-UV wurden unterhalb von 1000 A Photodissoziationen von H2, H2O und NH3 untersucht, bei denen elektronisch angeregte Bruchstücke auftreten. Der Nachweis der Fluoreszenz erfolgte hauptsächlich im Schumann-UV, zum geringeren Teil auch oberhalb von 2000 A. Durch geeignete Detektor- und Filterkombinationen ließen sich in einigen Fällen die Anregungszustände der Bruchstücke und damit die Dissoziationsprozesse identifizieren und deren Einsatzenergien bestimmen. Die Fluoreszenzintensitäten wurden in Abhängigkeit von der eingestrahlten Wellenlänge untersucht. Für gewisse Zerfallsprozesse konnten absolute Querschnitte gemessen werden.
Beim H2-Molekül tritt im Anregungsbereich unterhalb von 849 A die Dissoziation
(a) H2→ H(n=2)+H(n=1)
auf. Zerfälle mit höher angeregten H-Atomen:
(b) H2→H(n>2)+H(n=1)
kommen unterhalb von 750 A ebenfalls vor.
Beim H2O-Molekül wurden folgende Dissoziationen nachgewiesen:
(c) H2O → H (n=2) +OH (Χ2Π),
(d) H2O → H2(B1∑u+)+O (3P),
(e) Η2Ο → H(n=1) +ΟΗ(Α2Σ+).
Zerfälle mit angeregten O-Atomen im Triplettsystem kommen nicht vor. Die Dissoziationen (c), (d) und (e) setzen unmittelbar bei den jeweiligen Dissoziationsenergien (810 A, 767 A, 1360 A) ein. Angeregte H-Atome und H2-Moleküle entstehen bis 600 A und angeregte OH-Radikale bis etwa 850 A.
Beim NH3 treten zwischen 840 A und 450 A Dissoziationen mit angeregten H-Atomen auf. Bis 750 A kommt von diesen Zerfällen nur der energetisch niedrigste,
(f) NH3 → H(n=2) +NH2

vor. Dissoziationen mit angeregten H2-Molekülen finden nicht statt.
Die absoluten Querschnitte der Zerfälle mit angeregten H-Atomen im (n=2)-Zustand wurden mittels einer Eichung der Lα-Intensitäten durch den H2-Absorptionskoeffizienten bestimmt. Sie sind wellenlängenabhängig und betragen beim H2O bis zu 60 (cm-1) und beim NH3 bis zu 10 (cm-1).
Electrical Mobilities and Tracer-diffusion Coefficients of the Na and Tl Ions in the Molten (Na — Tl)NO3 System
Authors: Forcheri Sandro , Wagner Vittoriano 
Published: March 2015

The ionic mobilities and the diffusion coefficients of Na and Tl in the (Na-Tl) NO3 system have been determined by means of a zone electrophoresis and diffusion technique. The most significant feature of the Na mobility isotherm is its rapid variation with composition in the NaNO3 rich region.
The diffusion coefficients of both cations have been found to depend rather weakly on composition. The electrical and diffusional mobilities of both cations show trends opposite to that of the fluidity.
These results are discussed in terms of the anion polarization model.
Untersuchung der Emission eines 50 Hz-Rubin-Pulslasers
Authors: Röss D. , Zeidler G. 
Published: March 2015

Die quasikontinuierliche Emission eines 1-Zoll-Rubinlasers mit 50 Hz Impulsfolgefrequenz wurde näher untersucht. Die mittlere Leistung von 1 W wird in Einzelimpulsen von 1,3 ms Dauer abgegeben, deren Zeitverlauf besser als 2% reproduzierbar ist, abgesehen von Kurzzeitinstabilitäten mit einer Zeitkonstante kleiner als 100 µs (Spikes).
Das Fernfeld besteht aus Moden bis zur 16. transversalen Ordnung, die sich jedoch glatt summieren, so daß eine zeitlich stationäre Emission ohne erkennbare räumliche Minima entsteht. Die Winkelverteilung wird näherungsweise durch eine Gauss-Funktion gegeben.
Der im kalten Zustand planparallele Resonator verhält sich auf Grund von thermischen Effekten wie ein allgemein konfokaler Resonator mit 100 cm Krümmungsradius der Stirnflächen. Dies führt zu einer Strahlöffnung von etwa 1°, während die echte Divergenz bei 20‘ liegt.
Der zeitliche Einsatz der Laseremission ist wegen der räumlichen und zeitlichen Variation der Pumplichtverteilung eine Ortsfunktion im Strahlquerschnitt. Dies ist im Nah- und Fernfeld gleichermaßen zu beobachten.
Das elektromagnetische Emissionsspektrum wurde mit einer schnellen Photodiode und mit Meßempfängern in einem Frequenzbereich von 10 kHz bis 1 GHz analysiert. Das Spektrum der „spikes“ liegt zwischen 10 kHz und 1 MHz, während die Wechselwirkung der transversalen Moden zu Linien bei einigen 100 MHz führt.
Tritium Loss from Iron Meteorites by Solar Wind Hydrogen
Authors: Wagener K. 
Published: March 2015

An estimate of the diffusion loss of tritium from iron meteorites in space cannot be based, in a direct manner, on the results of diffusion measurements in the laboratory, because the hydrogen content of the samples in the laboratory is always higher by many orders of magnitude than is the tritium content of iron meteorites in space, which results from bombardement by cosmic rays. This is true because the kinetics of gas loss from a metal change with concentration and temperature, especially the kinetics of hydrogen loss from meteoritic iron, where the amounts of cosmic rayproduced tritium are sufficiently small to be trapped completely by chemisorption of nickel. Estimates based on diffusion data for hydrogen in the laboratory lead to much higher rates of hydrogen loss than can be expected for cosmic ray-produced tritium in meteorites.
In this connection, however, the fact has to be considered that meteoritic iron in space may not only contain hydrogen isotopes derived from cosmic ray-induced spallation processes, but also derived from solar wind bombardement. The steady-state hydrogen content of an iron meteorite, resulting from such bombardement in outer space, depends, of course, on the size and the structure of the meteoritic body. In general, the body will have to be assumed to possess a grain structure and this complicates the situation considerably. In any case, it can be shown that the steady-state hydrogen content is much higher than the tritium content and this makes it possible to use laboratory diffusion data in a calculation of the diffusion losses of tritium. By using the laboratory data of Festag, Fechtig and Schultes, it can be shown that cosmogenic tritium will be lost almost completely whenever the temperature is close to 0°C, or higher. Only meteorites consisting of grains of a size exceeding several millimeters retain tritium at such temperatures.
Landau Damping and Entropy
Authors: Winterberg F. 
Published: March 2015

It is shown that the well-known LANDAU-damping entropy paradox can be resolved by considering a macroscopic entropy as defined by CLAUSIUS instead of the microscopic entropy defined by BOLTZMΛNN. Although both entropy definitions are identical for equilibrium configurations, the same in general is not true for non-equilibrium configurations. To extend the entropy definition of CLAUSIUS to non-equilibrium configurations requires a generalization of the concept of temperature to nonequilibrium configurations. A natural generalization of the concept of temperature to non-equilibrium configurations is to put the temperature proportional to the mean square velocity fluctuation. In this way a macroscopic entropy can be defined which is then proportional to the logarithm of the mean square velocity fluctuation. In the case of LANDAU damping it can be shown that two states having the same statistical permutability and thus the same microscopic entropy may have different mean square velocity fluctuations. One should therefore consider, besides the microscopic disorder defined by BOLTZMANN, which is proportional to the logarithm of the permutability, a macroscopic disorder which is proportional to the logarithm of the mean square velocity fluctuation.
In the case of LANDAU damping the microscopic entropy does not change with time; the macroscopic entropy, however, increases steadily with time.
Calculation of Boson Masses in Higher New Tamm–Dancoff-Approximation in the Nonlinear Spinor Theory
Authors: Saller H. , Dürr H.P. 
Published: March 2015

Eigenvalue equations of bosons in the second step of the New Tamm-Dancoff-approximation (NTD) are investigated in the Hermitean formulation of the nonlinear spinor theory.
It is shown that three of the four derived equations lead to the same result, whereas one approximation is completely different and is supposed to give a useless result, because the suppressed 6-point function contains essential parts of the considered 2-point function. It is possible by a factorization of the equations of the second iteration to calculate a local graph. By taking this graph into consideration the eigenvalues of spin-0-particles obtained in lowest NTD are slightly corrected. For comparison the same questions are discussed in case of the anharmonical oscillator.
Über das unterschiedliche Ionisationsgleichgewicht wasserstoff- und alkali-ähnlicher Ionen in optisch dünnen Plasmen
Authors: Mahn C. 
Published: March 2015

There are many plasmas in which the populations of the various energy states of ions and electrons assume a steady state, but complete local thermal equilibrium is prevented because, on the one hand, radiation absorption is absent and, on the other, the electron density is too low.
Calculations for a plasma without radiation absorption show that: Where hydrogen-like ions are involved it is nearly in order to dispense with detailed calculations and described the ionization equilibrium with the assumption that the collisional ionization processes from the ground state can be equated with the radiative recombination processes to the ground state. For sufficiently low electron densities this leads to the Corona formula.
In the case of other ions, however, neglecting the excited states may result in serious errors. This is because these energy states — unlike those for hydrogen-like ions, which are relatively near the ionization limit — are distributed much more uniformly between the ground state and ionization limit. The implications of this behaviour are discussed with reference to alkali-like ions. A model for the term systems and the collision and radiation coefficients is used to derive the population densities and approximative ionization formulae. According to these the ratio of the densities of the lithium-like O VI ions and the next higher level of ions (O VII), for instance, may differ (for electron densities ne = 5 × 1017 cm–3) from the result of the Corona formula by a factor of 20.
Level-Crossing-Untersuchung der Hyperfeinstruktur von Sn117 und Sn119 im (5p6s) 3P1
0-Term des Sn I-Spektrums
Authors: Brieger M. , Zimmermann P. 
Published: March 2015

Using the level-crossing technique the following relations between the hyperfine structure constant A and the gj value of the (5p6s)3P1
0-term were determined for both the stable isotopes Sn117 and Sn119:
A117 = — 159,57(4) mK · gJ/1,380; A119 = — 167,01(4) mK · gJ/1,380.
From the width of the level-crossing signal a mean lifetime τ = 4,5(7) · 10-9 sec was deduced.