Einfluss einer PVD‐Al‐Zwischenschicht auf die Eigenschaften eines thermisch gespritzten Wärmedämmschichtsystems nach Temperaturwechselbelastung

Thermal barrier coatings (TBC) generally consist of a metallic bond coat (BC) and a ceramic top coat (TC). Co–Ni–Cr–Al–Y metallic super alloys and Yttria stabilised zirconia (YSZ) have been widely used as bond coat and top coat for thermal barrier coatings systems, respectively. As a result of long‐term exposure of thermal barrier coatings systems to oxygen‐containing atmospheres at high temperatures, a diffusion of oxygen through the porous ceramic layer occurs and consequently an oxidation zone is formed in the interface between ceramic top coat and metallic bond coat. Alloying components of the BC layer create a so‐called thermally grown oxides layer (TGO). One included oxide type is α‐Al₂O₃. α‐Al₂O₃ lowers oxygen diffusion and thus slows down the oxidation process of the bond coat and consequently affects the service life of the coating system positively. The distribution of the alloying elements in the bond coat layer, however, generally causes the formation of mixed oxide phases. The different oxide phases have different growth rates, which cause local stresses, micro‐cracking and, finally, delamination and failure of the ceramic top coat layer. In the present study, a thin Al inter‐layer was deposited by DC‐Magnetron Sputtering on top of the Co–Ni–Cr–Al–Y metallic bond coat, followed by thermal spraying of yttria‐stabilised zirconia (YSZ) as a top coat layer. The deposited Al inter‐layer is meant to transform under operating conditions into a closed layer with high share of α‐Al₂O₃ that slows down the growth rate of the resulting thermally grown oxides layer. Surface morphology and microstructure characteristics as well as thermal cycling behaviour were investigated to study the effect of the intermediate Al layer on the oxidation of the bond coat compared to standard system. The system with Al inter‐layer shows a smaller thermally grown oxides layer thickness compared to standard system after thermal cycling under same conditions.     

808‐nm‐Light‐Excited Lanthanide‐Doped Nanoparticles: Rational Design,Luminescence Control and Theranostic Applications

808 nm‐light‐excited lanthanide (Ln³⁺)‐doped nanoparticles (LnNPs) hold great promise for a wide range of applications, including bioimaging diagnosis and anticancer therapy. This is due to their unique properties, including their minimized overheating effect, improved penetration depth, relatively high quantum yields, and other common features of LnNPs. In this review, the progress of 808 nm‐excited LnNPs is reported, including their i) luminescence mechanism, ii) luminescence enhancement, iii) color tuning, iv) diagnostic and v) therapeutic applications. Finally, the future outlook and challenges of 808 nm‐excited LnNPs are presented.     

A reduced‐order representation of the Poincaré–Steklov operator: an application to coupled multi‐physics problems

This work investigates a model reduction method applied to coupled multi‐physics systems. The case in which a system of interest interacts with an external system is considered. An approximation of the Poincaré–Steklov operator is computed by simulating, in an offline phase, the external problem when the inputs are the Laplace–Beltrami eigenfunctions defined at the interface. In the online phase, only the reduced representation of the operator is needed to account for the influence of the external problem on the main system. An online basis enrichment is proposed in order to guarantee a precise reduced‐order computation. Several test cases are proposed on different fluid–structure couplings. Copyright © 2016 John Wiley & Sons, Ltd.     

A Monodispersed Spherical Zr‐Based Metal–Organic Framework Catalyst,Pt/Au@Pd@UIO‐66, Comprising an Au@Pd Core–Shell Encapsulated in a UIO‐66 Center and Its Highly Selective CO2 Hydrogenation to Produce CO

A Zr‐based metal–organic framework (MOF) catalyst, Pt/Au@Pd@UIO‐66, is assembled, where UIO‐66 is Zr₆O₄(OH)₄(BDC)₆ (BDC = 1,4‐benzenedicarboxylate). The gold nanoparticles (NPs) act as the core for the epitaxial growth of Pd shells, and the core–shell monodispersed nanosphere Au@Pd is encapsulated into UIO‐66 to control its morphology and impart nanoparticle functionality. The microporous nature of UIO‐66 assists the adsorption of Pt NPs, which in turn enhances the interaction between NPs and UIO‐66, favoring the formation of isolated and well‐dispersed Pt NP active sites. This MOF exhibits high catalytic activity and CO product selectivity for the reverse‐water–gas‐shift reaction in a fixed‐bed flow reactor.     

An alternative TLM method for steady‐state convection–diffusion

Recent papers have introduced a novel and efficient scheme, based on the transmission line modelling (TLM) method, for solving one‐dimensional steady‐state convection–diffusion problems. This paper introduces an alternative method. It presents results obtained using both techniques, which suggest that the new scheme outlined in this paper is the more accurate and efficient of the two. Copyright © 2009 John Wiley & Sons, Ltd.     

Investigating the Hybrid‐Structure‐Effect of CeO2‐Encapsulated Au Nanostructures on the Transfer Coupling of Nitrobenzene

Due to the obvious distinctions in structure, core–shell nanostructures (CSNs) and yolk–shell nanostructures (YSNs) exhibit different catalytic behavior for specific organic reactions. In this work, two unique autoredox routes are developed to the fabrication of CeO₂‐encapsulated Au nanocatalysts. Route A is the synthesis of well‐defined CSNs by a one‐step redox reaction. The process involves an interesting phenomenon in which Ce³⁺ can act as a weak acid to inhibit the hydrolysis of Ce⁴⁺ under the condition of OH^? shortage. Route B is the fabrication of monodispersed YSNs by a two‐step redox reaction with amorphous Co₃O₄ as an in situ template. Furthermore, the transfer coupling of nitrobenzene is chosen as a probe reaction to investigate their catalytic difference. The CSNs can gradually achieve the conversion of nitrobenzene into azoxybenzene, while the YSNs can rapidly convert nitrobenzene into azobenzene. The different catalytic results are mainly attributed to their structural distinctions.