bluuebunny/crossref_metadata_2025_split huggingface dataset:
Durch Spallationsreaktionen und Neutroneneinfang erzeugtes 36Cl in Meteoriten und die prae-atmosphärische Größe von Steinmeteoriten
Authors: Begemann F. , Vilcsek E. 
Published: March 2015

The 36Cl produced by spallation reactions and neutron capture on 35Cl has been measured separately in three stone meteorites and one iron meteorite.
The spallation produced 36Cl activities - given in dpm per kg (Fe+Ni + 10 x Ca) -have been found to be (20.5 ±2) for Abee - Centre, (21.8 ±2) for Abee - Surface, (21.3 -26.2) for Leedey, and ≦ (22 ±10) for Norton County- Surface. They are in good agreement with those found in iron meteorites of comparable size and known terrestrial age.
The neutron induced activities in the same samples are (0.21 ±0.2), (0.08 ± 0.17), (1.7 ±1), and ≦ (30 ± 15) dpm/100 mg Cl. In spite of the large uncertainties highly significant conclusions can be drawn from these data regarding the mass loss of the meteorites during approximately the last million years, either by space erosion or due to ablation during the passage through the terrestrial atmosphere. Based on calculations of EBERHARDT, GEISS, and LUTZ the ratio of post-atmospheric to pre-atmospheric radius derived for the three meteorites is Abee: rM/R=0.86 or rΜ/R > 0.7 on the 3 σ significance level, Leedey (meteorite shower): rM/R=0.5, and Norton County: rM/R=0.77 or rM/R > 0.63 (3 σ level).
No neutron induced activity could be detected in the iron meteorite Cranbourne (Nr. 4). The total and spallation produced 36Cl of two adjacent samples - although differing in their Cl content by more than a factor of twenty-was the same within the experimental limits of error (4.7 ± 0.2) dpm/kg. The low value is attributed to a high terrestrial age and/or the size of this meteorite. 39Ar could not be detected (< 0.64 dpm/kg. 3 σ level).
Atomic Distribution in Molten Silver-Tin Alloy
Authors: Joshi M. L. , Wagner C. N. J. 
Published: March 2015

Molten silver-tin alloys have been studied by x-ray diffraction technique, using a focusing Θ--Θ diffractometer with Mo-Ka radiation (quartz crystal monochromator in the diffracted beam). The scattered intensities Icoh
eu in electron units and the interference function I (K)=Icoh
eu/ƒ2 being the scattering factor) have been measured in the range of K=4 π sin Θ/λ = 1.4 Å-1 to K = 15 Å~-1 for 6 different alloy compositions at temperatures 100 °C above the liquidus line. Four alloys (from 62% to 82% Ag) were measured at 825 ℃.
The positions of the first maximum of Ieu or I(K) shift considerably with increasing silver content from K=2.25 Å-1 for pure Sn to K=2.64 Å-1 for pure Ag. The radial distribution function 4 π r2ϱ (r) and the probability function W (r) = ϱ (r)/ϱ0, where ϱ (r) and ϱ0 are the atomic and average atomic densities respectively, were obtained by FOURIER transform of I(K). The positions of the first maximum of 4 π r2ϱ (r), (i. e., r1) and of W(r), (i.e., r1
1) are a measure of the interatomic distances, and vary from r1
1 = 3.18 Å for Sn to r1
1= 2.86 Å for Ag. The plot of r1
1 vs. composition of the alloys shows a negative deviation from a linear law. A discontinuity appears in the curve in the range of 50-60% Ag. The coordination number Z increases rapidly on addition of Ag to Sn (Z = 8.5 for Sn) and reaches a value of about 11 beyond 60% Ag.
Messungen der Argon-Diffusion in KCl und KBr
Authors: Richter A. H. K. , Zimen K. E. 
Published: March 2015

Die Diffusion von radioaktivem Argon wurde in reinen und dotierten Einkristallen von KCl und KBr sowie in gepreßten Tabletten von KCl im Temperaturbereich von 300 — 700°C gemessen. Als Aktivierungsenergien wurden gefunden:
unterhalb 400°C 2,4 eV (55 kcal/mol) für KCl und 1,5 eV (36 kcal/mol) für KBr, oberhalb 400°C 0.6 eV (14 kcal/mol) für KCl und 0,4 eV (8 kcal/mol) für KBr.
Die Gasabgabe erfolgt unterhalb 400°C in den ersten 40 — 80 Minuten verzögert. Mit SrCl2 bzw. K2S dotierte KCl-Kristalle unterscheiden sich im Diffusionsverhalten nicht von KCl-Einkristallen. In den KCl-Tabletten beeinflussen geschlossene Poren die Edelgasabgabe.
Diffusion of Non-Gaseous Fission Products in UO2 Single Crystals II
Authors: Oi Noboru , Takagi Jinzaburo 
Published: March 2015

The release of short-lived non-gaseous fission products from UO2 single crystals was studied in the temperature range of 1400 —2500°C by means of post-irradiation annealing. The release of the fission products studied appears to follow the kinetics of a diffusion process. Analysis of the data obtained gives the following diffusion constant,
DΜο = 3.9 × 10-4 exp(-54,000/RT), DI = 1.5 x 10-3 exp(-59,000/RT), DTe = 6.6 × 10-3 exp(— 70,000/RT), DLa (tentative) =2.2 x 10-6 exp (— 35,000/RT)
where the dimensions of D and RT are cm2/sec and cal/mol, respectively.
Bestimmung der Wärmeleitfähigkeit heißer Gase aus der Temperaturgrenzschicht im Stoßrohr
Authors: Smeets G. 
Published: March 2015

Es wird eine Theorie der reinen Temperaturgrenzschicht entwickelt, wie sie sich nach der Reflexion der Stoßwelle am geschlossenen Ende des Stoßrohres ausbildet. Dann wird das Interferenzbild berechnet, das entsteht, wenn man die Temperaturgrenzschicht im Differentialinterferometer betrachtet.
Da die Temperaturgrenzschicht und deren Interferenzbild von der Wärmeleitfähigkeit des im Stoßrohr befindlichen Gases abhängen, kann man aus den Interferenzaufnahmen auf die Wärmeleitfähigkeit schließen. Es wird dafür ein allgemeines Verfahren angegeben. Dann wird am Beispiel der Luft die Wärmeleitfähigkeit im Temperaturintervall 1140°K &lt; T &lt; 6075°K und bei der Dichte ρ = 1/10 ρN bestimmt.
Neutron Cross Sections for Some Threshold Reactions
Authors: Lagerwall Torbjörn 
Published: March 2015

Three neutron reactions leading to production of the rare gases Ar41 and Xe135 have been investigated. Single crystal samples of KF, CaF2, and BaF2 were irradiated in the Berlin reactor and the target-free absolute activities of the rare gas isotopes measured by a β-γ-coincidence method. The calculated cross sections are
K41(n,p) Ar41: σ= ( 2,73±0,41) mb; σ0= (98,6±14,8) mb;
Ca44 (n,a)Ar41: σ = (61,1 ±9,2) μb; σ0= (64,7± 9,7) mb;
Ba138(n,a)Xe135: σ= ( 1,9 ±0,3) μb; σ0= ( 4,9± 0,7) mb.
The first set of values are valid for a fission-neutron spectrum. The second set are calculated cross sections for the high energy plateau. They can be considered as valid for 15 MeV neutrons.
Self-Diffusion in Molten Silver Nitrate
Authors: Sjöblom C.-A. , Andersson J. 
Published: March 2015

The self-diffusion coefficient of the Ag+-ion in molten AgNO3 has been measured with the glass fibre paper strip technique in the temperature interval 220—336 °C. The result can be described by the equation
D=3.2 × 10—4 exp{-3400/(RT)} cm2s—1.
A comparison with the results obtained by other workers shows good agreement between the two sets of values. Possible sources of error are discussed.
Ionisationsgleichung für optisch dünne Plasmen
Authors: Bohn W. L. 
Published: March 2015

An ionization formula for optically thin plasmas is proposed taking into account collisional ionization and both collisional and radiative recombination.
This rather simple formula allows the calculation of the plasma components over the whole range of electron densities and temperatures. In cases of extremely low or extremely high electron densities it approaches the well known corona, and SAHA-equation (for electron temperature), respectively. Furthermore it is shown that the SAHA-equation is not valid in a high temperature plasma having a great ionic charge even at high electron densities, and that the proposed ionization formula should be used. Results at constant pressure or constant electron density are given in numerous diagrams.
Spallation, Fission, and Neutron Capture Anomalies in Meteoritic Krypton and Xenon
Authors: Marti K. , Eberhardt P. , Geiss J. 
Published: March 2015

Measurements of the Kr and Xe concentrations and isotopic compositions in five meteorites are reported. Experimental techniques and reproducibility are discussed in detail. In the Stannern achondrite 75% of the total Kr and 30% of the total Xe are due to cosmic ray induced spallation reactions. Also Bruderheim and H - Ausson show distinct spallation components. The isotopic composition of pure spallation Kr is derived as Kr78 : Kr80 : Kr82 : Kr83 : Kr84 = 0.179 : 0.495 : 0.765 : 1.00 : 0.63
and of spallation Xe as Xe124 : Xe126 : Xe128 : Xe130 : Xe131 : Xe132 = 0.590 : 1.00 : 1.45 : 0.97 : 3.9 : 0.9. It is shown that the spallation components found were produced by the cosmic radiation late in the history of the meteorite during a period given by the radiation age. The observed Xe128/Xe124 spallation ratio rules out a substantial contribution of spallation products in the xenon of carbonaceous chondrites. The Xe fission spectrum derived by ROWE and KURODA from Pasamonte is corrected for spallation and the following composition is obtained for fission Xe : Xe131 : Xe132 : Xe134 : Xe136· = 0.22 : 1.00 : 1.02 : 1.00.
In Mezö-Madaras and Abee Kr80, Kr82 and Xe128 excesses are found, due to (n.γ) reactions on Br and I. It is shown that neutrons produced by the cosmic radiation during the radiation age can account for the observed effect in Abee and the evidence so far suggests that this is also true for Mezö-Madaras.
Über den Einfluß von Fänger- und Löschmolekülen auf die Reichweite von Triplett-Excitonen in geschmolzenem Naphthalin
Authors: Bässler Heinz 
Published: March 2015

Recently it was found that in zone-refined, molten naphthalene triplet-excitons are able to diffuse over a distance of about 1 cm. This diffusion length can be greatly reduced by addition of quenchers. If the quenching molecules have a triplet level lying below the level of the host (energy difference ΔΕ), they can trap the exciton. For ΔE ⪅ 0.5 eV the probability that the exciton is released thermally and given to the host molecules again, exceeds the desactivation probability. Therefore the quencher only acts in slowing down the mean velocity of the moving exciton, the life-time remains constant. In this case enhancement of the photocurrent in naphthalene can be obtained by additional excitation of the S1 state of the quencher followed by intersystem-crossing and population of the desactivation probability of neighbouring host-molecules. Therefore the life-time of the excitons electrons increases.
Molecules wih a T1-state above the T1-state of the host can quench the exciton-motion, too, if the life-time of their T1-state is reduced by spin-orbit-coupling (p-dichlorbenzene). They increase the desactivation probability of neighbouring guest-molecules. Therefore the life-time of the excitons decreases.
A model is proposed predicting the decrease of the diffusion length with quencher-concentration according to

, which is in good agreement with the experiments. Thereby energy-transfer is presumed to be proportional to c. Finally it is reported that guest-molecules with higher electron-affinity can produce a cathodic photoeffect, too, by forming cations.
Das Diffusionsverhalten des Wasserstoffes in der Legierung Pd : Ag = 77 : 23 in Abhängigkeit von seiner Konzentration
Authors: Küssner A. 
Published: March 2015

Es wird eine Methode zur Bestimmung des Wasserstoff-Diffusionskoeffizienten in Metallfolien in Abhängigkeit von der Wasserstoffkonzentration beschrieben. Die Legierung Pd : Ag = 77 : 23 wurde bei 30, 50 und 75 °C bei Wasserstoffkonzentrationen zwischen 0 und 0,4 H/Me untersucht. Entsprechende Ergebnisse werden mitgeteilt. Der in der homogenen Metallphase absorbierte Wasserstoff zeigt eine starke Konzentrationsabhängigkeit des Diffusionskoeffizienten.
Ferner wird über Potentialmessungen an zugbelasteten PdAg-Folien berichtet. Es wird der experimentelle Beweis für die Hypothese geliefert, die Druckhysterese sei auf mechanische Spannungen zurückzuführen.
Die experimentellen Ergebnisse sprechen gegen die Annahme, der absorbierte Wasserstoff sei in Protonen und Elektronen dissoziiert.
Interferometrische Untersuchung der Deformation von Laserstäben während des Pumpvorganges
Authors: Bayer E. , Schaack G. 
Published: March 2015

The elongation of neodymium-glass laser-rods (LG 52 and LG 55 of Schott u. Gen., Mainz), the curvature and the tilting of their end surfaces have been measured by means of a MICHELSON-interferometer, a rotating-drum-camera and a laser illuminating the interferometer with short, isolated “spikes” during the pumping pulse of the rod. The pumping arrangements used for the tested rods are an elliptical cylinder and a rotational ellipsoid. A linear dependence of the observed deformation from the absorbed pumping energy is observed for this four-level material, so that the elongation of the rod and the curvature and the tilting angle of the surfaces can be expressed in terms of the pumping energy.
The deformation measured in the elliptical cylinder pumping arrangement is compared with the calculated density of the absorbed energy within a laser rod illuminated by such an elliptical mirror. The main features of the observations are represented by this calculation.
Über die Wechselwirkung eines Plasmastrahls mit einem achsensymmetrischen Magnetfeld
Authors: Ragaller K. 
Published: March 2015

The interaction of a plasma jet with an axisymmetric magnetic field, is calculated in linear approximation for a periodic and for a convergent or divergent field configuration.
The solution depends on the MACH number, the magnetic pressure number, and the magnetic REYNOLDS number.
In the convergent field, the plasma is decelerated. If the flow is supersonic, this is connected with a contraction of the jet leading beyond equilibrium and therefore being followed by an expansion. In the subsonic case, the stopping is accompanied by a broadening of the jet.
With increasing magnetic REYNOLDS number, “wakes” appear which extend upstream or downstream, depending on the values of the magnetic pressure number and the MACH number.
Field Ionisation Studies Using a Double Focussing Mass Spectrometer
Authors: Beynon J. H. , Fontaine A. E. , Job B. E. 
Published: March 2015

Intense field ionisation mass spectra have been obtained with an A.E.I. M.S.7 mass spectrometer, used with very simple modifications to the ion source.
Some features of the spectra of a variety of compounds are given and the spectrum of acetone is discussed in detail. A special feature of this spectrum is the variety of ions with a mass greater than that of a single molecule.
The relatively small energy spread of the field ion source enabled resolving powers, higher than those possible with a spark source, to be obtained. Multiplets occurring in the spectra were easily resolved.
β ν- und β α-Winkelkorrelationen beim Zerfall von 8Li und 8B
Authors: Eichner H. , Lauterjung K. H. , Meinhardt H. , Schimmer B. , Schmidt-Rohr U. 
Published: March 2015

The βv- and βα-angular correlations for the decay of 8Li→8Be*→2α previously studied have been remeasured with an improved experimental setup. In addition we have measured these correlations for the decay 8B→8Be→2 α.
For the coefficient b in the angular correlation between β-, ν- and α-particle for Gamow—Teller interaction W (b,,ϑ,φ)dΩ=[1+bv/c) cos ϑ·cos φ] dΩ
we got b(8Li) = —1,01 ± 0,07 and b (8B) =1,05 ± 0,12. Both results are in agreement with pure axial vector interaction.
For the coefficient B in the angular correlation between β- and α-particle W(Θ) dΩ= (1+A·cos Θ+B·cos2Θ) dΩ
we got B (8Li) = (+0.0031 ± 0.0003) · Wβ and B (8B) = (-0.0023 ±0.0003) ·Wβ . The experimental result
δ=B (8Li) —B (8B) = (0.0054 ± 0.0004) Wβ

is within the range predicted by the Conserved Vector Current theory.
Die Lithiumhäufigkeit und die Struktur der äußeren Konvektionszone in sonnenähnlichen Sternen
Authors: Böhm K.-H. 
Published: March 2015

The observations of the Lithium abundance and the isotope ratio Li6/Li7 in stars are briefly reviewed and some simple conclusions are drawn. It is emphasized that — in addition to the mechanism proposed by BODENHEIMER — a slow (timescale ≈ 109 years) mixing process in main sequence F and G stars is necessary to account for the observations.
The present state of the theory of convective overshooting is reviewed in this context. Two new models of the outer solar convection zone are presented. The temperature at their lower boundaries are 2.04 x 106 °K and 2.27 x 106 °K, showing that only a rather small convective overshoot may be sufficient for mixing the matter in the convection zone with the layers, in which Li7 is burnt.
Our models differ from earlier ones, because (when calculating the mean stratification) we take into account the condition that the mixing length can nowhere be larger than the distance from the nearest boundary of the convection zone. It is shown that this approach also leads to a slight change of the numerical factors in the formulae usually used.
Neutron Exposure Ages of Meteorites
Authors: Fireman E. L. 
Published: March 2015

Co60 and Ar39 were measured in a number of recently fallen meteorites. From these data the amount of shielding surrounding the samples in space was estimated. In the carbonaceous chondrite, Murray, the Co60 activity was very large compared to the Co60 activities in the other chondrites even though the Ar39 activities were almost identical. In the iron meteorites there was an inverse relationship between the Co60 and Ar39 activities; shielding material increased the Co60 activity and decreased the Ar39 activity.
In the cases of Abee and Bruderheim, neutron exposure ages were obtained from the Kr80/Co80, Kr82/Co60, and Xe128/Co60 ratios because the Co60 was measured in large samples from the interior of the same fragment in which krypton, xenon, bromine, and iodine had previously been measured. The neutron exposure ages were approximately an order of magnitude larger than the spallation exposure ages. The order-of-magnitude differences in the exposure ages could be attributed to space erosion or to an ancient neutron irradiation.
Ein hochauflösendes γ-Spektrometer mit Ge(Li)-Detektor und Feldeffekttransistor-Vorverstärker
Authors: Kalbitzer S. , Melzer W. , Kemmer J. , Walther P. 
Published: March 2015

Die vorliegende Arbeit beschreibt die Herstellung hochauflösender Ge (Li) -Detektoren nach verschiedenen Driftmethoden und den Entwurf eines schnellen Vorverstärkers mit einem Feldeffekt-Transistor in der Eingangsstufe.
Die γ-Strahlung von 60Co wurde mit 3 keV HWB aufgelöst. Für den Fano-Faktor ergab sich ein Wert von 0,20-0,25 im Energiebereich von 300-2750 keV.
S. C. F. Study of the OH3
+ Ion
Authors: Rajagopal P. 
Published: March 2015

Λ convergent self consistent field calculation for the OH3
+ ion is reported. The results indicate that the isolated ion is planar, with an OH distance of 1.9007 a. u. ( = 1.006 Å nearly), self consistent field energy of —76.3722 a. u., and force constants of k1= 6.84 × 105 dynes/cm and kΔ/l2=2.39 × 105 dynes/cm.
The correlation contribution to the binding energy for several ten electron systems are analysed in the Appendix.
Erklärung stellarer und planetarer Magnetfelder durch einen turbulenzbedingten Dynamomechanismus
Authors: Steenbeck M. , Krause F. 
Published: March 2015

In a foregoing paper 1 the effects of a turbulent motion on magnetic fields were investigated. Especially turbulence was treated under the influence of CORIOLiS-forces and gradients of density and/or turbulence intensity. It was shown that on these conditions the average cross-product of velocity and magnetic field has a non-vanishing component parallel to the average magnetic field. Here we give the consequences of this effect for rotating, electrically conducting spheres.
At first a sphere rotating with constant angular velocity is investigated. The quadratic effect provides for dynamo maintainance of the magnetic fields. A field of dipol-type has the weakest condition for maintainance. Applications to the magnetic field of the earth show a good agreement with the conceptions of the physical state of the earth’s core.
For a second model differential rotation is included. We have also dynamo maintainance. Since we have to assume that generally the angular velocity is a function decreasing with the distance from the centre of the sphere, the calculations show that we have a preferred self-excited build-up of a quadrupol-type field. This model may be applicable to magnetic stars.
Finally we look for dynamo maintainance of alternating fields. We consider the skin-depth to be small compared with the radius of the sphere, then we have plane geometry. The existence of periodical solutions is proved. Applications to the general magnetic field of the sun, which has a period of 22 years, are discussed.
Berechnung kinetischer Isotopeneffekte für die Reaktion von Methyljodid mit Hydroxid-Ion
Authors: Willi A. V. 
Published: March 2015

Kinetic carbon-13, deuterium, and oxygen-18 isotope effects are calculated from force constants for the SN2 reaction of CH3I with OH-. The secular equations for the vibrational frequencies of reactants and transition states are solved on an IBM 7094 computer. Values for 7 force constants of the planar CH3 moiety in the transition state (with an sp2 atom) are obtained by comparison with suitable stable molecules. The stretching force constants ƒCO = ƒ11, ƒCI = ƒ22, and ƒ12 in the transition state are chosen as linear functions of x, the degree of bond making and bond breaking, with the aid of eqs. (1) and (2).
The carbon isotope effect as a function of x exhibits a flat maximum near x=0.6. If the bending force constants ƒHCO and ƒHCI are kept constant, k12/k13 is significantly lower than its maximum value only for values of x ≦ 0.3 and x ≧ 0.8. There is only a small influence of x on the deuterium isotope effect, kH/kD (compare rates of CH3I and CD3I). However, kH/kD) is strongly dependent on ƒHCO and ƒHCI . The oxygen-18 isotope effect decreases with increasing x. Experimental data of the D isotope effect — if they were available — could be used to adjust the bending force constants ƒHCO and ƒHCI (— or to adjust ƒHCO if ƒHCI is held constant). The degree of unsymmetry of the transition state could then be estimated with the aid of the C isotope effect. Experimental data of the O isotope effect would supply information on the direction of the unsymmetry — which is needed for a distinction between 2 possible values of x —. There is approximate agreement between the calculated and the experimental temperature dependence of the carbon-13 isotope effect.
The Electrical Conductivity of a Partially Ionized Argon-Potassium Plasma in a Magnetic Field
Authors: Feneberg W. 
Published: March 2015

In the case of small deviations from thermal equilibrium the second ENSKOG approximation is used as a starting point for solving the BOLTZMANN equation of the electrons in a partially ionized plasma. The distribution function is expanded according to LAGUERRE polynomials up to the order of 3. In this order the electrical conductivity of a LORENTZ gas, which is known exactly, is obtained to an accuracy of roughly 5%. The approximation tested in this way was then used to calculate the conductivity of an argon-potassium mixture at electron temperatures between 2000°K and 3500°K.
If only he collisions between electrons and argon atoms were to be considered, the electrical conductivity in the absence of a magnetic field would, in view of the RAMSAUER effect, be greater by a factor of 2.8 than that obtained with an infinitely strong magnetic field. When the interaction with the potassium atoms and the COULOMB interaction are taken into account as well the conductivity in the magnetic field varies by about 20%.
Matrix Representation for Calculation of the Second-Order Aberration in Ion Optics
Authors: Takeshita Isao 
Published: March 2015

The matrix representation for calculating the ion trajectory is extended to include the secondorder aberration terms.
Properties of the matrix and relations between its elements are discussed.
As an example of the application of the matrix method, the second-order coefficients of a homogeneous magnetic field of arbitrary shape are derived and the relations between the matrix elements and Hinterberger's notations are shown.