Determination of the Tin Stable Isotopic Composition in Tin‐bearing Metals and Minerals by MC‐ICP‐MS          下载免费PDF全文

Gerhard Brügmann  Daniel Berger  Ernst Pernicka 《Geostandards and Geoanalytical Research》2017,41(3):437-448

This study uses MC‐ICP‐MS for the precise analysis of the stable tin isotopic composition in ore minerals of tin (cassiterite, stannite), tin metal and tin bronze. The ultimate goal is to determine the provenance of tin in ancient metal objects. We document the isotope compositions of reference materials and compare the precision of different isotope ratios and the accuracy of different procedures of mass fractionation correction. These data represent a base with which isotopic data of future studies can be directly compared. The isotopic composition of cassiterite and stannite can be determined after reduction to tin metal and bronze, respectively. Both metals readily dissolve in HCl, but while the solutions of tin metal can be directly measured, the bronze solutions must be purified with an anion exchanger. The correction of the mass bias is best performed with an internal Sb standard and an empirical regression method. A series of Sn isotope determinations on commercially available mono‐element Sn solutions as well as reference bronze materials and tin minerals show fractionations ranging from about ?0.09‰ to 0.05‰/amu. The combined analytical uncertainty (2s) was determined by replicate dissolutions of reference materials of bronze (BAM 211, IARM‐91D) and averages at about 0.005‰/amu.  相似文献   

Elektronenmikroskopische Untersuchung von Nadeleisenerzooiden in Pulverpräparaten und Dünnschnitten     

Prof. Dr. Otto Ernst Radczewski  Dr. Paula Schneiderhöhn 《Contributions to Mineralogy and Petrology》1962,8(5):349-353

Zusammenfassung Elektronenmikroskopische Untersuchungen isolierter Nadeleisenerzooide in Ultradünnschnitten und Pulverpräparaten zeigen; daß das Nadeleisenerz hier in Form sechsseitiger rhombischer Blättchen (Durchmesser in der Größenordnung von 100–300 Å) vorliegt. Dünnschnittbilder lassen eine lageweise Anordnung der Blättchen im Ooid erkennen.  相似文献   

Trace-element concentrations in single circumstellar silicon carbide grains from the Murchison meteorite     

Sachiko Amari  Peter Hoppe  Ernst Zinner  Roy S. Lewis 《Meteoritics & planetary science》1995,30(6):679-693

Abstract— Concentrations of the trace elements Mg, Al, Ca, Ti, V, Fe, Sr, Y, Zr, Ba and Ce were determined by ion microprobe mass spectrometry in 60 individual silicon carbide (SiC) grains (in addition, Nb and Nd were determined in 20 of them), from separate KJH (size range 3.4–5.9 μm) of the Murchison carbonaceous meteorite, whose C-, N- and Si-isotopic compositions have been measured before (Hoppe et al., 1994) and provide evidence that these grains are of stellar origin. The selected SiC grains represent all previously recognized subgroups: mainstream (20 < ¹²C/¹³C < 120; 200 < ¹⁴N/¹⁵N; Si isotopes on slope 1.34 line), grains A (¹²C/¹³C < 3.5), grains B (3.5 < ¹²C/¹³C < 10), grains X (¹⁵N excesses, large ²⁸Si excesses) and grains Y (150 < ¹²C/¹³C < 260; Si isotopes on slope 0.35 line). Data on these grains are compared with measurements on fine-grained SiC fractions. Trace-element patterns reflect both the condensation behavior of individual elements and the source composition of the stellar atmospheres. A detailed discussion of the condensation of trace elements in SiC from C-rich stellar atmospheres is given in a companion paper by Lodders and Fegley (1995). Elements such as Mg, Al, Ca, Fe and Sr are depleted because their compounds are more volatile than SiC. Elements whose compounds are believed to be more refractory than SiC can also be depleted due to condensation and removal prior to SiC condensation. Among the refractory elements, however, the heavy elements from Y to Ce (and Nd) are systematically enriched relative to Ti and V, indicating enrichments by up to a factor of 14 of the s-process elements relative to elements lighter than Fe. Such enrichments are expected if N-type carbon stars (thermally pulsing AGB stars) are the main source of circumstellar SiC grains. Large grains are less enriched than small grains, possibly because they are from different AGB stars. The trace-element patterns of subgroups such as groups A and B and grains X can at least qualitatively be understood if grains A and B come from J-type carbon stars (known to be lacking in s-process enhancements shown by N-type carbon stars) or carbon stars that had not experienced much dredge-up of He-shell material and if grains X come from supernovae. However, a remaining puzzle is how stars become carbon stars without much accompanying dredge-up of s-process elements.  相似文献   

Comets and the formation of planets     

Ernst J. Öpik 《Astrophysics and Space Science》1973,21(2):307-398

A morphological study of the physical and dynamical processes of planet formation is presented, with emphasis on the intermediary role of comet nuclei. Although guided by a particular model of the evolution of the pre-planetary solar nebula, implying the freezing-out of hydrogen in the region of the giant planets, the derivations and conclusions are of wider import, applicable to other cosmogonic models as well as to certain phases of star formation. The items evaluated physically, dynamically, or statistically comprise: (1) the total number mass of comets in Oort's cloud; (2) a re-evaluation of the diameters and masses of cometary nuclei; (3) the processes of nucleation from gravitational and Boltzmann instabilities of gaseous media to agglomerations of particulate matter as conditioned by inbuilt angular momentum; (4) the statistical-dynamical conditions and time scales of orbital interaction of comets with the planets and the consequences of disintegration.A consistent model proposes the formation of comets and planets in pre-planetary rings of the residual solar nebula, with subsequent ejection, chiefly by Jupiter, of the comets to Oort's sphere. Screening by absorbing matter is not only probable, but necessary to protect the comets from dis-integration during the process of ejection.Paper dedicated to Prof. H. C. Urey on the occasion of his 80th birthday on 29 April, 1973.This work has been currently supported by grants from the National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland.  相似文献   

Direkte Berechnung der Ionenradien in Alkalihalogeniden aus der Lichtbrechung bzw. Molrefraktion und dem Ionenabstand     

Ernst Kordes 《Mineralogy and Petrology》1962,8(1):13-23

Zusammenfassung Es wird gezeigt, daß man allein aus der Lichtbrechung und dem Ionenabstand (bzw. über die Molrefraktion) die Ionenradien in Alkalihalogeniden berechnen kann, ohne daß hierzu die Kenntnis irgendeines Ionenradius erforderlich ist. Die neu angegebenen Gleichungen enthalten nur physikalisch eindeutig definierte Größen und keinerlei empirische Konstanten.Die vermittels dieser Gleichungen aus Salzpaaren von Alkalihalogeniden mit gemeinsamem Anion aus Ionenabstand und Lichtbrechung berechneten Ionenradien stimmen gut mit den vonV. M. Goldschmidt subtraktiv (mit r=1·33 Å für F^–) order vonL. Pauling halbtheoretisch erhaltenen Ionenradien überein.Herrn Prof.K. H. Scheumann zum 80. Geburtstag gewidmet.  相似文献   

Launch window study for the highly eccentric orbit satellite HEOS-1     

Ernst A. Roth 《Celestial Mechanics and Dynamical Astronomy》1970,2(3):369-381

A satellite with a high eccentricitye0.95 is strongly perturbed by the sun and the moon. This fact and mission constraints restrict considerably the possible launch times for such a satellte. The launch window calculations can be performed in two steps in order to save computing time. An approximate analytical solution provides a general survey of the launch opportunities. An accurate numerical approach is then necessary for the exact definition of the launch window. In the case of the orbit of HEOS-1 (satellite 68 10901), moreover the consideration of the injection errors has been of great importance.Presented at the Conference on Celestial Mechanics, Oberwolfach, Germany, August 17–23, 1969.  相似文献   

Navigation formula to A. Busemann's variation problem of space travel     

Ernst Hölder 《Celestial Mechanics and Dynamical Astronomy》1970,2(3):446-447

The indicatrix of the variation problem is given (1) by the perturbation differential equation for the semi-major axis and eccentricity, and (2) by a relation between the momentum and eccentric anomaly. The Hamiltonian equations of an extremal solution, therefore, reduce to a navigation equation. The remaining perturbation equations for the longitude of perihelion and the mean longitude at epoch, finally, yield the time dependence that gives the most economic fuel consumption.  相似文献   

Interstellar graphite in meteorites: Isotopic compositions and structural properties of single graphite grains from Murchison     

Ernst Zinner  Sachiko Amari  Brigitte Wopenka  Roy S. Lewis 《Meteoritics & planetary science》1995,30(2):209-226

Abstract— One hundred forty-three carbon grains, ranging in size from 2 to 8 μm, from two chemical and physical separates from the Murchison CM2 chondrite, were analyzed by ion microprobe mass spectrometry for their C- and N-isotopic compositions. Both separates are enriched in the exotic noble gas component Ne-E(L). Ninety grains were also analyzed for their H and O contents and 118, for Si. Thirteen grains were analyzed by micro-sampling laser Raman spectroscopy. Round grains have large C-isotopic anomalies with ¹²C/¹³C ratios ranging from 7 to 4500 (terrestrial ratio = 89). Nitrogen in these grains is also anomalous but shows much smaller deviations from the terrestrial composition, ¹⁴N/¹⁵N ratios ranging from 193 to 680 (terrestrial ratio = 272). Spherulitic aggregates and non-round compact grains have normal C-isotopic ratios but ¹⁵N excesses (up to 35%). Raman spectra of the analyzed grains indicate varying degrees of crystalline disorder of graphite with estimated in-plane crystallite dimensions varying from 18 Å (highly disordered, similar to terrestrial kerogen) to ～750 Å (well-crystallized graphite). Element contents of H, O, and Si are correlated with one another, and H and O are probably present in the form of organic molecules. On the basis of morphology, the round grains fall into two groups: grains with smooth, shell-like surfaces (“onions”) and grains that appear to be dense aggregates of small scales (“cauliflowers”). “Onions” tend to have lower trace element contents, isotopically light C (¹²C/¹³C > 89) and a high degree of crystalline order, whereas “cauliflowers” have a larger spread in trace element contents and C-isotopic ratios (they range from isotopically light to heavy) but tend to have a low degree of crystalline order. However, these differences exist only on average, and no clear distinction can be made for individual grains. A few limited conclusions can be drawn about the astrophysical origin of the carbon grains of this study. The ¹⁵N excesses in spherulitic aggregates and non-round grains can be explained as the result of ion-molecule reactions in molecular clouds. The round grains, on the other hand, must have formed in stellar atmospheres (circumstellar grains). Grains with isotopically light C must have formed in stellar environments characterized by He-burning, either in the atmosphere of Wolf-Rayet stars during the WC phase or in the He-burning, ¹²C-rich zone of a massive star, ejected by a supernova explosion. Isotopically heavy C is produced by H-burning in the CNO cycle. Possible sources for grains with heavy C are carbon stars (AGB stars during the thermally pulsing phase) or novae, but the detailed distribution of ¹²C/¹³C ratios agree neither with the distribution observed in carbon stars nor with theoretical predictions for these two types of stellar sources.  相似文献   

Interstellar Grains in Primitive Meteorites: Diamond,Silicon Carbide,and Graphite     

Edward Anders  Ernst Zinner 《Meteoritics & planetary science》1993,28(4):490-514

Abstract— Primitive meteorites contain a few parts per million (ppm) of pristine interstellar grains that provide information on nuclear and chemical processes in stars. Their interstellar origin is proven by highly anomalous isotopic ratios, varying more than 1000-fold for elements such as C and N. Most grains isolated thus far are stable only under highly reducing conditions (C/O > 1), and apparently are “stardust” formed in stellar atmospheres. Microdiamonds, of median size ～ 10 Å, are most abundant (～ 400–1800 ppm) but least understood. They contain anomalous noble gases including Xe-HL, which shows the signature of the r- and p-processes and thus apparently is derived from supernovae. Silicon carbide, of grain size 0.2–10 μm and abundance ～ 6 ppm, shows the signature of the s-process and apparently comes mainly from red giant carbon (AGB) stars of 1–3 solar masses. Some grains appear to be ≥10⁹ a older than the Solar System. Graphite spherules, of grain size 0.8–7 μm and abundance <2 ppm, contain highly anomalous C and noble gases, as well as large amounts of fossil ²⁶Mg from the decay of extinct ²⁶Al. They seem to come from at least three sources, probably AGB stars, novae, and Wolf-Rayet stars.  相似文献   

Strategic decision making in shipping     

Ernst G. Frankel 《Marine Policy》1982,6(4):259-264

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