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  • 1
    Publikationsdatum: 2023-12-15
    Beschreibung: The lithosphere of the Moon has been deformed by tectonic processes for at least 4 billion years, resulting in a variety of tectonic surface features. Extensional large lunar graben formed during an early phase of net thermal expansion before 3.6 Ga. With the emplacement of mare basalts at ∼3.9–4.0 Ga, faulting and folding of the mare basalts initiated, and wrinkle ridges formed. Lunar wrinkle ridges exclusively occur within the lunar Maria and are thought to be the result of superisostatic loading by dense mare basalts. Since 3.6 Ga, the Moon is in a thermal state of net contraction, which led to the global formation of small lobate thrust faults called lobate scarps. Hence, lunar tectonism recorded changes in the global and regional stress fields and is therefore an important archive for the thermal evolution of the Moon. Here, we mapped tectonic features in the non‐mascon basin Mare Tranquillitatis and classified these features according to their respective erosional states. This classification aims to provide new insights into the timing of lunar tectonism and the associated stress fields. We found a wide time range of tectonic activity, ranging from ancient to recent (3.8 Ga to 〈50 Ma). Early wrinkle ridge formation seems to be closely related to subsidence and flexure. For the recent and ongoing growth of wrinkle ridges and lobate scarps, global contraction with a combination of recession stresses and diurnal tidal stresses, as well as with a combination of South Pole‐Aitken ejecta loading and true polar wander are likely.
    Beschreibung: Plain Language Summary: The lithosphere of the Moon has been deformed by tectonic processes for at least 4 billion years, resulting in a variety of tectonic surface features. Simple compressional asymmetric landforms are called lobate scarps and complex compressional features, which form as a result of the combination of faulting and folding, are known as wrinkle ridges. Lunar wrinkle ridges only occur within the lunar Maria. It has been argued that their formation is linked to the subsidence of the dense mare basalts, which would have happened in the early history of the Moon. We mapped all of these features within a dark lunar region called Mare Tranquillitatis and then studied their morphology on high‐resolution images. Based on their morphology, we found a wide time range of tectonic activity, ranging from ancient to recent. Large wrinkle ridges seem to be ancient and influenced by subsidence. Smaller wrinkle ridges and lobate scarps show signs of recent activity. They likely formed recently within the last hundred million years because of the Moon's current state of global compression.
    Beschreibung: Key Points: Early compressional tectonism in Tranquillitatis, in the form of wrinkle ridges, is presumably related to subsidence and basin loading. Later tectonism could reflect the evolution from a basin‐localized to a global stress field and the continued growth of ancient faults. Recent wrinkle ridge and lobate scarp formation in Tranquillitatis occurred in the last 50 Ma and is influenced by a global stress field.
    Beschreibung: https://doi.org/10.5281/zenodo.7551409
    Beschreibung: https://darts.isas.jaxa.jp/planet/pdap/selene/
    Beschreibung: https://doi.org/10.17189/1520341
    Beschreibung: http://imbrium.mit.edu/DATA/SLDEM2015
    Beschreibung: https://doi.org/10.17189/1519529
    Beschreibung: https://quickmap.lroc.asu.edu/
    Beschreibung: http://www.yongtechnology.com/download/georose
    Schlagwort(e): ddc:523 ; Moon ; tectonics ; wrinkle ridges ; lobate scarps ; lithosphere ; tectonic mapping
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2023-01-21
    Beschreibung: Thermal fatigue has been proven to be of fundamental importance for the nature and evolution of surfaces of airless bodies in the solar system. It is a rock erosive process acting in conjunction with meteoroid bombardment. We set up an experiment to simulate the diurnal temperature variation at 1 AU of centimeter sized sample cubes using a liquid nitrogen cooled cryostat, allowing to study unexplored conditions, that is, high vacuum and temperatures of 200 K similar to those occurring on the Moon. The sample cubes are investigated using scanning electron microscopy and micro computed tomography scans before and after 10, 20, 50, 100, and 400 total cycles. Cycling of the lunar anorthosite Northwest Africa (NWA) 11273 and the eucrite NWA 11050 reveal different behaviors: Whereas NWA 11273 responds to the cycling with micro‐flaking of tenth‐of‐µm‐sized grains on its surface and only limited crack growth, the eucrite NWA 11050 is less affected by micro‐flaking but the growth of cracks is observed to occur throughout the whole experiment. The rate of crack formation and growth is lower when compared to previously reported results on ordinary and carbonaceous chondritic samples carried out under nitrogen atmosphere and above 250 K. We propose that the size of particles and their rate of production by thermal fatigue highly depends on the mineralogy of the exposed rock and areas with mature rocks are prone to produce fine‐grained soil, while primary rocks such as basalts are likely to produce blocky regolith in a first step.
    Beschreibung: Plain Language Summary: Thermal fatigue—the fatigue of a material due to temperature variation—is important for the breakdown of rocks on the surface of planetary bodies such as the Moon, asteroids, and also on the Earth and the formation of a fine‐grained soil, called the regolith. With an improved experimental setup, we simulate the diurnal temperature variations at a solar distance of 1 AU under high vacuum conditions between 200 and 375 K for the lunar anorthosite breccia Northwest Africa (NWA) 11273 and the eucritic basalt NWA 11050. We show that both types of rocks respond different to these temperature excursions: The basaltic eucrite forms cracks over the course of 400 cycles and the lunar anorthosite tends to flake off tenth‐of‐µm‐sized grains with only limited cracking. The overall obtained cracking rates are lower when compared to those from previous experiments under nitrogen atmosphere, indicating the retrieved breakdown rates are lower than previously reported and the type of resulting soil depends strongly on the mineralogy of the exposed rock.
    Beschreibung: Key Points: We report on an updated experimental setup to simulate thermal fatigue in high vacuum instead of nitrogen atmosphere to reflect natural conditions. The crack formation and growth rates differ between the lunar anorthosite and eucritic basalt and are generally 〈50% of those reported previously. We propose that the resulting regolith depends highly on the mineralogy of starting materials, which control the breakdown of the rock.
    Beschreibung: Alexander von Humboldt Foundation
    Beschreibung: https://doi.org/10.26022/IEDA/112505
    Schlagwort(e): ddc:549.112 ; thermal fatigue ; eucrite ; Moon ; regolith ; thermal breakdown
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 352 (1967), S. 24-26 
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Cr(t-OC4H9)4 is prepared in a simple manner with good yield by oxidation of CrIII chloride.
    Notizen: Cr(t-OC4H9)4 läßt sich durch Oxydation von Chrom(III)-chlorid in einfacher Weise mit guter Ausbeute darstellen.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 96 (1963), S. 3008-3016 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Durch die optische Untersuchung der Reduktion von CrO3 mit Chlorwasserstoff in Eisessig konnte ein Reaktionsablauf nach \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$$ {\rm CrO}_{\rm 3} \; \to \;{\rm CrO}_{\rm 2} {\rm Cl}_{\rm 2} \; \to \;[{\rm CrOCl}_{\rm 4}]^\Theta /[{\rm CrOCl}_{\rm 5}]^{2 \Theta} \,\mathop \to \limits^{hv} \,[{\rm Cr(H}_{\rm 2} {\rm O}){\rm Cl}]^{2 \Theta} $$\end{document} unter Ausschluß weiterer Zwischenstufen bewiesen werden. Chlorochromat(V)- Anionen bilden außer den bekannten WEINLANDschen Salzen Komplexe der Formel [HNR3NH][CrOCl3] und [R3NCOR][CrOCL4]. Das mit [CrOCl5]2⊖ im Gleichgewicht stehende CrOCl3 ist durch Umsetzung von CrO3 bzw. CrO2Cl2 mit Thionyl- oder Sulfurylchiorid kristallin erhältlich. Die Addition von Benzoesäureanhydrid an CrOCl3führt zu Cl3Cr(OCOC6H5)2, das auch aus Benzoylchlorid und CrO3 direkt zugänglich ist.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1559-1563 
    ISSN: 0009-2940
    Schlagwort(e): Boranes, organo(organoimino)- ; Diazadiboretidines ; Borazines ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A Further Contribution to the Stabilization of Iminoboranes RB≡NR'The iminoboranes (tBuB≡NR (1a, b, R=iPr, Ph) and RB≡NR (1c, d; R=Me3CCH2, Me3SiCH2) were prepared by gas-phase thermolysis of Cl(tBu)B=N(R)SiMe3 (6a, b) and R2BN3 (7c, d), respectively. At room temperature, the molecules 1a-c cyclodimerize to the diazadiboretidines 2a-c, whereas the borane 1d cyclotrimerizes to the borazine 3d; these stabilization reactions are discussed in terms of the steric demand of the organic ligands. The ethyloboration of 1a, c with BEt3 BCl to 1a yields the diborylamine 9d. Benzyl azide and 1c, d undergo a [3 + 2] cycloaddition with formation of the tetrazaborolidines 10c, d.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 569 (1989), S. 7-15 
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Contributions to the Chemistry of Phosphorus. 191. On the Reaction Behavior of Sodium Tetraphosphinoborate NaB(PH2)4Sodium tetraphosphinoborate rearranges to sodium heptaphosphinodiborate, Na[(PH2)3B—PH2—B(PH2)3] (1), at moderate temperatures in the presence of tetrahydrofuran. By reacting NaB(PH2)4 with BH3 ß THF sodium tetrakis(boranephosphino)borate, NaB(PH2BH3)4 (2), is formed, which has a remarkable thermal stability, but is not stable without solvent. With methyl iodide, the easily decomposible triphosphinoborane-methylphosphane, B(PH2)3PH2CH3 (3), has been obtained. The 31P- and 11B-NMR data of 1-3 are reported and discussed.
    Notizen: Natriumtetraphosphinoborat lagert sich in Gegenwart von Tetrahydrofuran schon bei mäßigen Temperaturen in Natrium-heptaphosphinodiborat, Na[(PH2)3B—PH2—B(PH2)3] (1), um. Bei der Reaktion von NaB(PH2)4 mit BH3 · THF entsteht Natriumtetrakis(boranphosphino)borat, NaB(PH2BH3)4 (2), das eine bemerkenswerte thermische Stabilität aufweist, lösungsmittelfrei aber nicht beständig ist. Mit Methyliodid wird das leicht zersetzliche Triphosphinoboranmethylphosphan, B(PH2)3PH2CH3 (3), gebildet. Die 31P- und 11B-NMR-Daten von 1-3 werden mitgeteilt und diskutiert.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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