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91.
Ohne Zusammenfassung
Herrn Prof. P. Rona sind wir für seine rege Anteilnahme und liebenswürdige Unterstützung bei der Durchführung dieser Arbeit
zu aufrichtigem Dank verpflichtet. 相似文献
92.
Ohne Zusammenfassung 相似文献
93.
F. Ibottson H. Brearley Fried C. B. Murray G. P. Maury Hj. Lidholm und C. Ramovino 《Fresenius' Journal of Analytical Chemistry》1905,44(8-9):561-563
Ohne Zusammenfassung 相似文献
94.
Biopolymer sequence comparison to identify evolutionarily related proteins, or homologs, is one of the most common tasks in bioinformatics. Support vector machines (SVMs) represent a new approach to the problem in which statistical learning theory is employed to classify proteins into families, thus identifying homologous relationships. Current SVM approaches have been shown to outperform iterative profile methods, such as PSI-BLAST, for protein homology classification. In this study, we demonstrate that the utilization of a Bayesian alignment score, which accounts for the uncertainty of all possible alignments, in the SVM construction improves sensitivity compared to the traditional dynamic programming implementation over a benchmark dataset consisting of 54 unique protein families. The SVM-BALSA algorithms returns a higher area under the receiver operating characteristic (ROC) curves for 37 of the 54 families and achieves an improved overall performance curve at a significance level of 0.07. 相似文献
95.
Hj. Matzke 《辐射效应与固体损伤》2013,168(1-4):317-325
Abstract The radiation enhanced diffusion (coefficient D*) of U-233 and Pu-238 in UO2 and (U, Pu)O2 with 2.5 and 15% Pu was measured during fission in a nuclear reactor. Normal diffusion sandwiches with a thin tracer layer were used. A radio-frequency furnace allowed the temperatures to be varied between 130 and 1400°. Neutron fluxes (7 × 1012 to 1.2 × 1014 n cm?2 s?1) and irradiation times (56 to 334 h) were also varied to cover ranges of fission rates [Fdot] between 7× 1011 and 6.4 × 1013 f cm?3 s?1 and of doses F between 4.2 × 1017 and 3.1 × 1019 f cm3. Below ~1000°, D* was completely athermal and increased linearly with [Fdot]. It was described by D* = A[Fdot] with A = 1.2× 10?29cm5. A possible temperature dependence was indicated between ~1000and 1200°. The results are explained in terms of thermal and pressure effects of fission spikes and are related with other studies of radiation damage as well as with technologically interesting processes occurring in UO2 during irradiation. 相似文献
96.
R. Gremaud A. Borgschulte C. Chacon J.L.M. van Mechelen H. Schreuders A. Züttel B. Hjörvarsson B. Dam R. Griessen 《Applied Physics A: Materials Science & Processing》2006,84(1-2):77-85
The structural, optical and dc electrical properties of MgxAl1-x (0.2≤x≤0.9) gradient thin films covered with Pd/Mg are investigated before and after exposure to hydrogen. We use hydrogenography, a novel high-throughput optical technique, to map simultaneously all the hydride forming compositions and the kinetics thereof in the gradient thin film. Metallic Mg in the MgxAl1-x layer undergoes a metal-to-semiconductor transition and MgH2 is formed for all Mg fractions x investigated. The presence of an amorphous Mg-Al phase in the thin film phase diagram enhances strongly the kinetics of hydrogenation. In the Al-rich part of the film, a complex H-induced segregation of MgH2 and Al occurs. This uncommon large-scale segregation is evidenced by metal and hydrogen profiling using Rutherford backscattering spectrometry and resonant nuclear analysis based on the reaction 1H(15N,αγ)12C. Besides MgH2, an additional semiconducting phase is found by electrical conductivity measurements around an atomic [Al]/[Mg] ratio of 2 (x=0.33). This suggests that the film is partially transformed into Mg(AlH4)2 at around this composition. PACS 78.20.-e; 68.55.-a; 64.75.+g 相似文献
97.
Hj. Matzke 《Fresenius' Journal of Analytical Chemistry》1984,319(6-7):801-808
Summary The method considered safest for isolation of nuclear waste is vitrification (solidification in a glass or glassceramic matrix) with long-term storage in stable geological repositories. Borosilicate glasses are candidates for this purpose on a world-wide scale. Though it is very unlikely that water will ever have access to these repositories, the leaching (corrosion in aqueous solutions) of glasses is studied. Rutherford backscattering of beams of charged particles (e.g. He-ions of 2–3 MeV energy) is shown to be a versatile technique to study surface layers and to obtain information on their thickness and composition. The method is non-destructive and can be applied to layers with thicknesses in the range of about 0.1 to 2 m. Results for nuclear waste glasses leached in H2O or in quinary salt solution (Q-brine) with and without presence of material from the metal container are presented. Presence of steel is shown to greatly enhance leaching rates by preventing glass components to become saturated in the leachant.
Rutherford-Rückstreuung zur Messung von Korrosionsschich ten an Gläsern zur Langzeitlagerung radioaktiver Abfälle
Zusammenfassung Die Verglasung nuklearer radioaktiver Abfälle (Verfestigung in einer Glasoder Glaskeramikmatrix) mit Langzeitlagerung in stabilen geologischen Lagerstätten wird als sicherste Methode zur Isolation der Abfälle betrachtet. Borosilicatgläser sind weltweit Hauptkandidaten für diesen Zweck. Obzwar es sehr unwahrscheinlich ist, daß Wasser jemals Zugang zu diesen Lagerstätten haben wird, werden Auslaugprozesse (Korrosion in wäßrigen Lösungen) der Gläser untersucht. Die Rutherford-Rückstreuung geladener Teilchenstrahlen (z.B. He von 2–3 Me V Energie) wird als vielseitige Methode zur Untersuchung von Oberflächenschichten vorgestellt, die Information liefert über Schichtdicke und Schichtzusammensetzung. Die Methode ist zerstörungsfrei und kann für Schichten im Dickenbereich von ca. 0,1–2 m benutzt werden. Ergebnisse werden beschrieben für Gläser für nukleare Abfälle, die in H2O oder in quinärer Salzlösung (Q-brine) allein oder in Gegenwart von Proben der vorgesehenen metallischen Behältermaterialien ausgelaugt wurden. Es wird gezeigt, daß in Gegenwart von Stahl die Auslaugraten wesentlich erhöht werden, da eine Sättigung von Glaskomponenten in der Auslauglösung verhindert wird.相似文献
98.
M. Mehring F. Hentsch Hj. Mattausch A. Simon 《Zeitschrift für Physik B Condensed Matter》1989,77(3):355-356
We report on the asymmetric field distribution of the triangular vortex lattice in the superconductor Tl2Ba2CuO6 as observed by205Tl NMR atB
a
=4.26 T. A penetration depth of =1700±100 Å is obtained. 相似文献
99.
LnHal2Hn— New Phases in the Ternary System Ln/Hal/H. II.: Preparation The hydride dihalides, LnHal2(H,D)n, have been prepared from LnHal2 or from mixtures of LnHal3 and LnHn in welded tantalum ampoules under defined hydrogen pressures. Under 1 atm hydrogen CeBr2H0.87 (at 770°C), CeI2H0.90, CeI2D0.96 and GdI2H0.97 (at 800°C respectively) are formed as dark blue transparent platelets with a weak metallic luster. The compounds could be hydrogenated at 550°C to the colourless compounds LnHal2H1.00. From the equilibrium pressure isotherm (at 800°C) the lowest possible H-content of CeI2Hn is determined to be n = 0.33 at a H2-pressure of 0.25 mbar. The continuous variation of the H-content is characterized by a, likewise, continuous alteration of the lattice constants from a = 4.209(1) Å to 4.1697(8) Å and c = 15.218(6) Å to 15.440(2) Å for n = 0.33 to 1.00. Neither CeCl2 nor CeCl2Hn could be prepared. According to our investigations, the phase described as LaBr2 can not be prepared as a binary compound. Attempts to prepare it from LaBr2H0.90 were unsuccessful. In contrast, GdI2 can be prepared hydrogen free and has the heavy-atom structure of GdI2Hn. 相似文献
100.