Landing and catalytic characterization of individual nanoparticles on electrode surfaces

We demonstrate a novel and versatile pipet-based approach to study the landing of individual nanoparticles (NPs) on various electrode materials without any need for encapsulation or fabrication of complex substrate electrode structures, providing great flexibility with respect to electrode materials. Because of the small electrode area defined by the pipet dimensions, the background current is low, allowing for the detection of minute current signals with good time resolution. This approach was used to characterize the potential-dependent activity of Au NPs and to measure the catalytic activity of a single NP on a TEM grid, combining electrochemical and physical characterization at the single NP level for the first time. Such measurements open up the possibility of studying the relation between the size, structure and activity of catalyst particles unambiguously

Synchronization of Josephson oscillations in mesa array of BSCCO single crystal through the Josephson plasma waves in base crystal

Using mesa array of $\rm{Bi_{2}Sr_{2}CaCu_{2}O_{8}}$ single crystal was demonstrated recently as a promising route to enhance the radiation power generated by Josephson oscillations in mesas. We study the synchronization in such an array via the plasma waves in the base crystal. First, we analyze plasma oscillations inside the base crystal generated by the synchronized mesa array and the associated dissipation. We then solve the dynamic equation for superconducting phase numerically to find conditions for synchronization and to check the stability of synchronized state. We find that mesas are synchronized when the cavity resonance of mesas matches with that of the base crystal. An optimal configuration of mesa arrays is also obtained.Comment: 6.3 pages, 7 figure

Silicon pore optics mirror modules for inner and outer radii

Athena (Advanced Telescope for High Energy Astrophysics) is an x-ray observatory using a Silicon Pore Optics telescope and was selected as ESA's second L-class science mission for a launch in 2028. The x-ray telescope consists of several hundreds of mirror modules distributed over about 15-20 radial rings. The radius of curvature and the module sizes vary among the different radial positions of the rings resulting in different technical challenges for mirror modules for inner and outer radii. We present first results of demonstrating Silicon Pore Optics for the extreme radial positions of the Athena telescope. For the inner most radii (0.25 m) a new mirror plate design is shown which overcomes the challenges of larger curvatures, higher stress values and bigger plates. Preliminary designs for the mounting system and its mechanical properties are discussed for mirror modules covering all other radial positions up to the most outer radius of the Athena telescope

Landing and Catalytic Characterization of Individual Nanoparticles on Electrode Surfaces

We demonstrate a novel and versatile pipet-based approach to study the landing of individual nanoparticles (NPs) on various electrode materials without any need for encapsulation or fabrication of complex substrate electrode structures, providing great flexibility with respect to electrode materials. Because of the small electrode area defined by the pipet dimensions, the background current is low, allowing for the detection of minute current signals with good time resolution. This approach was used to characterize the potential-dependent activity of Au NPs and to measure the catalytic activity of a single NP on a TEM grid, combining electrochemical and physical characterization at the single NP level for the first time. Such measurements open up the possibility of studying the relation between the size, structure and activity of catalyst particles unambiguously