Zur Darstellung und Reaktivität einiger intermetallischer Verbindungen

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Robotic observation pipeline for small bodies in the solar system based on open-source software and commercially available telescope hardware

The observation of small bodies in the Space Environment is an ongoing important task in astronomy. While nowadays new objects are mostly detected in larger sky surveys, several follow-up observations are usually needed for each object to improve the accuracy of orbit determination. In particular objects orbiting close to Earth, so called Near-Earth Objects (NEOs) are of special concern as a small but not negligible fraction of them can have a non-zero impact probability with Earth. Additionally, the observation of manmade space debris and tracking of satellites falls in the same class measurements. Telescopes for these follow-up observations are mainly in a aperture class between 1 m down to approximately 25 cm. These telescopes are often hosted by amateur observatories or dedicated companies like 6ROADS specialized on this type of observation. With upcoming new NEO search campaigns by very wide field of view telescopes, like the Vera C. Rubin Observatory, NASA’s NEO surveyor space mission and ESA’s Flyeye telescopes, the number of NEO discoveries will increase dramatically. This will require an increasing number of useful telescopes for follow-up observations at different geographical locations. While well-equipped amateur astronomers often host instruments which might be capable of creating useful measurements, both observation planning and scheduling, and also analysis are still a major challenge for many observers. In this work we present a fully robotic planning, scheduling and observation pipeline that extends the widely used open-source cross-platform software KStars/Ekos for Instrument Neutral Distributed Interface (INDI) devices. The method consists of algorithms which automatically select NEO candidates with priority according to ESA’s Near-Earth Object Coordination Centre (NEOCC). It then analyses detectable objects (based on limiting magnitudes, geographical position, and time) with preliminary ephemeris from the Minor Planet Center (MPC). Optimal observing slots during the night are calculated and scheduled. Immediately before the measurement the accurate position of the minor body is recalculated and finally the images are taken. Besides the detailed description of all components, we will show a complete robotic hard- and software solution based on our methods.TS-R acknowledges funding from the NEO-MAPP project (H2020-EU-2-1-6/870377). This work was (partially) funded by the Spanish MICIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” by the “European Union” through grant RTI2018-095076-B-C21, and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia “María de Maeztu”) through grant CEX2019-000918-M

Manganese oxide phases and morphologies: A study on calcination temperature and atmospheric dependence

Manganese oxides are one of the most important groups of materials in energy storage science. In order to fully leverage their application potential, precise control of their properties such as particle size, surface area and Mnx+ oxidation state is required. Here, Mn3O4 and Mn5O8 nanoparticles as well as mesoporous α-Mn2O3 particles were synthesized by calcination of Mn(II) glycolate nanoparticles obtained through an economical route based on a polyol synthesis. The preparation of the different manganese oxides via one route facilitates assigning actual structure–property relationships. The oxidation process related to the different MnOx species was observed by in situ X-ray diffraction (XRD) measurements showing time- and temperature-dependent phase transformations occurring during oxidation of the Mn(II) glycolate precursor to α-Mn2O3 via Mn3O4 and Mn5O8 in O2 atmosphere. Detailed structural and morphological investigations using transmission electron microscopy (TEM) and powder XRD revealed the dependence of the lattice constants and particle sizes of the MnOx species on the calcination temperature and the presence of an oxidizing or neutral atmosphere. Furthermore, to demonstrate the application potential of the synthesized MnOx species, we studied their catalytic activity for the oxygen reduction reaction in aprotic media. Linear sweep voltammetry revealed the best performance for the mesoporous α-Mn2O3 species

Size-Dependent Lattice Distortion in ε‑Ag₃Sn Alloy Nanoparticles

In this study, the crystallographic structure of orthorhombic ε-phase Ag₃Sn nanoparticles with different sizes between 7 and 120 nm was studied by X-ray diffraction, and the influence of the size and the composition of the nanocrystals on the lattice parameters were investigated. Rietveld refinement was used to confirm the orthorhombic (space group <i>Cmcm</i>) crystal structure and to determine the lattice parameters and the size of the crystals for all nanoparticle samples. We found an anisotropic decrease of the lattice parameters which furthermore depends on the size of the crystallites. Etching the nanoparticles with sulfuric acid allows us to control the Ag/Sn ratio of the Ag₃Sn nanoparticle samples. The lattice parameters decrease for higher Ag/Sn ratio

Size-Dependent Strain of Sn/SnO_<i>x</i> Core/Shell Nanoparticles

The lattice constants of metallic nanoparticles shrink with respect to that of a bulk material. This behavior affects the properties of nanoscaled crystallites and can influence their application potential. In this work, we investigate the size-dependent lattice parameters of core/shell Sn/SnO_<i>x</i> nanoparticles, synthesized via a simple chemical reduction method. Therein, the use of appropriate surface ligands, reaction temperature, and reaction time allows us to tune the mean particle size from 6 to 104 nm. X-ray powder diffraction revealed that the ß-Sn reflections shift toward higher angles for smaller particles, showing a size-dependence of the lattice constants. The change in the lattice constants varies, depending on the direction, and can be described as an inverse function of the diameter of the crystallites. The different degree of deformation can be explained by the direction dependency of the bulk modulus <i>K</i> and the interface energy γ of the monocrystalline tin nanoparticles