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[en] In Germany, the competence of operational radiation protection is based on the technical qualification in radiation protection necessary for radiation protection officers, which can only be acquired by successfully attending a recognised radiation protection course, appropriate training and sufficient practical experience. Once acquired, the radiation protection expertise must be renewed at least every 5 years by successfully attending a recognized updating course.
[de]Die Kompetenz des betrieblichen Strahlenschutzes basiert in Deutschland auf der für Strahlenschutzbeauftragte notwendigen Fachkunde im Strahlenschutz, zu deren Erwerb grundsätzlich der erfolgreiche Besuch eines anerkannten Strahlenschutzkurses, eine geeignete Ausbildung und genügend praktische Erfahrung notwendig sind. Einmal erworben, muss die Fachkunde im Strahlenschutz durch den erfolgreichen Besuch eines anerkannten Aktualisierungskurses mindestens alle 5 Jahre aufgefrischt werden.
[en] The intermetallic compounds RETX (RE = La–Nd, Sm, Gd, Tb; T = Pd, Pt; X = In, Sn) have been synthesized from the elements by arc-melting and subsequent annealing sequences in tube or induction furnaces. The samples were characterized through Guinier powder diffraction patterns, and several structures were refined from single crystal X-ray diffractometer data. These indium and tin intermetallics crystallize with the orthorhombic CePdIn-type structure, space group Pnma. The palladium (platinum) and indium (tin) atoms in the RETX structures build up complex three-dimensional [TX] polyanionic networks in which the rare earth atoms fill cavities. The striking structural motifs concern the indium, respectively tin substructures, in which part of the indium and tin atoms have distorted square planar homoatomic coordination environments: In1In1In2 units in PrPdIn with interatomic distances 325 pm In1-In1 and 332 pm In1–In2 as well as Sn1Sn1Sn2 units in PrPtSn with the larger distances of 356 pm for Sn1–Sn1 and of 344 pm for Sn1-Sn2. Temperature dependent magnetic susceptibility measurements have indicated Pauli paramagnetism or diamagnetism for the lanthanum compounds, van-Vleck paramagnetism for SmPtIn and Curie-Weiss paramagnetism for the remaining compounds. Antiferromagnetic ordering was detected at T = 4.0(1) K for CePtIn and at T = 3.5(1) K for SmPtIn. CePtIn shows a metamagnetic transition at an external magnetic field of 47(3) kOe.
[en] Metal–Lewis acid cooperation provides new opportunities in catalysis. In this work, we report a new type of palladium–borane cooperation involving anionic Pd species. The air‐stable DPB palladium complex 1 (DPB=diphosphine‐borane) was prepared and reacted with KH to give the Pd borohydride 2, the first monomeric anionic Pd species to be structurally characterized. The boron moiety acts as an acceptor towards Pd in 1 via Pd→B interaction, but as a donor in 2 thanks to B‐H‐Pd bridging. This enables the activation of C−Cl bonds and the system is amenable to catalysis, as demonstrated by the hydro‐/deutero‐dehalogenation of a variety of (hetero)aryl chlorides (20 examples, average yield 85 %). (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] A photochemical method for converting aliphatic alcohols into boronic esters is described. Preactivation of the alcohol as a 2‐iodophenyl‐thionocarbonate enables a novel Barton–McCombie‐type radical deoxygenation that proceeds efficiently with visible light irradiation and without the requirement for a photocatalyst, a radical initiator, or tin or silicon hydrides. The resultant alkyl radical is intercepted by bis(catecholato)diboron, furnishing boronic esters from a diverse range of structurally complex alcohols. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] Reactions of carbon monoxide (CO) with tBuMeSiLi and (E)‐(tBuMeSi)(tBuMeSi)C=Si(SiMetBu)Li⋅2 THF (4) were studied both experimentally and computationally. Reaction of tBuMeSiLi with CO in hexane yields the first stable tetra‐silyl di‐ketyl biradical [(tBuMeSi)COLi] (3). Reaction of 4 with CO yields selectively and quantitatively the first reported 1‐silaallenolate, (tBuMeSi)(tBuMeSi)C=C=Si(SiMetBu)OLi⋅THF (5). Both 3 and 5 were characterized by X‐ray crystallography and biradical 3 also by EPR spectroscopy. Silaallenolate 5 reacts with MeSiCl to produce siloxy substituted 1‐silaallene (tBuMeSi)(tBuMeSi)C=C=Si(SiMetBu)OSiMe. The reaction of 4 with CO provides a new route to 1‐silaallenes. The mechanisms of the reactions of tBuMeSiLi and of 4 with CO were studied by DFT calculations. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] The BiVO photoelectrochemical (PEC) electrode in tandem with a photovoltaic (PV) cell has shown great potential to become a compact and cost‐efficient device for solar hydrogen generation. However, the PEC part is still facing problems such as the poor charge transport efficiency owing to the drag of oxygen vacancy bound polarons. In the present work, to effectively suppress oxygen vacancy formation, a new route has been developed to synthesize BiVO photoanodes by using a highly oxidative two‐dimensional (2D) precursor, bismuth oxyiodate (BiOIO), as an internal oxidant. With the reduced defects, namely the oxygen vacancies, the bound polarons were released, enabling a fast charge transport inside BiVO and doubling the performance in tandem devices based on the oxygen vacancy eliminated BiVO. This work is a new avenue for elaborately designing the precursor and breaking the limitation of charge transport for highly efficient PEC‐PV solar fuel devices. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] The NiP@CdZnS nanoparticles photocatalyzed self‐coupling of p‐xylene was reported here, and the corresponding coupling product 1,2‐di‐p‐tolylethane was obtained. The reaction could be extended to toluene derivatives with electron‐donating and electron‐withdrawing substituents. NiP@CdZnS nanoparticles had already been characterized by XRD, ICP‐AES, SEM, TEM, UV/Vis, FL, XPS. The Mott–Schottky curves of NiP@CdZnS were made through electrochemical methods. An active carbon free‐radical was captured through ESR measurement under irradiation. The research demonstrated this photocatalytic system feasible for the self‐coupling reaction of toluene derivatives. (© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] In this work a 1,2,4‐triazole derivative 1‐(4‐aminobenzyl)‐1,2,4‐triazole (abtz) was utilized, one new cadmium(II) coordination polymer, namely [Cd(abtz)I] (1) was prepared through the powerful solvo‐thermal synthetic strategy. In compound 1, the abtz building blocks are interlinked through the central Cd ions forming the two‐dimensional (2D) layer coordination framework. Powder X‐ray diffraction (PXRD) characterization also reveals that we have prepared the pure phases of coordination polymer 1. Optical properties have been determined, which can behave the excellent photo‐luminescent emission of coordination polymer 1. Photo‐luminescent experiment also reveals that coordination polymer 1 can behave the highly sensitive detection for acetone molecules with high K value (K = 4.12 ×10 L·mol) in the recyclable detection fashion. Additionally, coordination polymer 1 also can behave the highly sensitive detection for pollutant dichromate with excellent quenching efficiency K (K = 2.12 × 10 L·mol) and low detection limit [38 × 10 mM (S/N = 3)]. UV/Vis, photo‐luminescent lifetime, and PXRD patterns also have been determined to analyze the detection mechanism. (© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] Interfacial phase‐change memory (iPCM) based on layer‐structured Ge‐Sb‐Te crystals has been recently proposed, offering an energy‐efficient implementation of nonvolatile memory cells and supplementing the development of Ge‐Sb‐Te‐based phase‐change random access memories (PRAMs). Although the working principle of iPCM is still under debate, it is believed that layer‐switching plays a role in the switching process between the low‐resistance and high‐resistance states of iPCM memory cells. However, the role of Ge in forming swapped bilayers - the key elements for layer‐switching - is not yet clarified. This work manages to achieve layer‐switching in SbTe thin films by manipulating the formation of bilayer defects using magnetron sputtering and post‐thermal annealing. By combining scanning transmission electron microscopy (STEM) experiments with density functional theory (DFT) calculations, the essential role of Sb‐Te intermixing is elucidated in stabilizing swapped bilayers at a low energy cost. In situ STEM experiments provide a real‐time and real‐space view of dynamical reconfiguration of van der Waals‐like gaps in SbTe thin films under electron‐beam irradiation. The results show that the Ge atoms are not necessary for the formation and motion of swapped bilayers, providing atomic insights on the layer‐switching mechanism in layer‐structured binary and ternary group V‐ and IV–V‐tellurides for memory applications. (© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[en] In the present work, the effect of reinforcement fiber diameter on elevated temperature bending creep deformation behavior of metal matrix composite is studied. Bending creep tests have been performed on Ni nanocomposite considering different fiber diameters using molecular dynamics simulations. Common neighbor analysis and dislocation analysis have been performed to analyze the deformation behavior and its underlying mechanism at the atomic scale during the bending creep process. Results have revealed that the specimen having thinner fiber exhibits better creep properties and higher plasticity due to the combined influence of shear band interactions and work softening. Whereas, work hardening and twin-detwin mechanisms are responsible for the quasi-cleavage fracture of the specimen having 4 nm diameter fiber.