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Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)
2022, Klioner, S.A., Lindegren, L., Mignard, F., Hernández, J., Ramos-Lerate, M., Bastian, U., Biermann, M., Bombrun, A., De Torres, A., Gerlach, E., Geyer, R., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J.-L., Hambly, N.C., Harrison, D.L., Hestroffer, D., Hodgkin, S.T., Hilger, T., Holl, B., Janben, K., Jevardat De Fombelle, G., Jordan, S., Krone-Martins, A., Lanzafame, A.C., Löffler, W., Marchal, O., Marrese, P.M., Moitinho, A., Hobbs, D., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Lammers, U.L., Sarro, L.M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., Van Leeuwen, M., Abbas, U., Ábrahám, P., Abreu Aramburu, A., Aerts, C., McMillan, P.J., Aguado, J.J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M.A., Alves, J., Anderson, R.I., Anglada Varela, E., Antoja, T., Baines, D., Steidelmüller, H., Baker, S.G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M.A., Bassilana, J.-L., Bauchet, N., Teyssier, D., Becciani, U., Bellazzini, M., Berihuete, A., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bossini, D., Bouquillon, S., Raiteri, C.M., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A.G., Buzzi, R., Bartolomé, S., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M.I., Carrasco, J.M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Bernet, M., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W.J., Cornez, T., Castañeda, J., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., De Laverny, P., De Luise, F., Clotet, M., De March, R., De Ridder, J., De Souza, R., Del Peloso, E.F., Del Pozo, E., Delbo, M., Delgado, A., Delisle, J.-B., Demouchy, C., Dharmawardena, T.E., Davidson, M., Diakite, S., Diener, C., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fabricius, C., Fienga, A., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Garralda Torres, N., Gavel, A., Gavras, P., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., González-Núñez, J., González-Santamaría, I., González-Vidal, J.J., Granvik, M., Guillout, P., Guiraud, J., Gutiérrez-Sánchez, R., Guy, L.P., Hatzidimitriou, D., Hauser, M., Haywood, M., Helmer, A., Helmi, A., Portell, J., Sarmiento, M.H., Hidalgo, S.L., Hładczuk, N., Holland, G., Huckle, H.E., Jardine, K., Jasniewicz, G., Jean-Antoine Piccolo, A., Jiménez-Arranz, O., Juaristi Campillo, J., Rowell, N., Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kordopatis, G., Korn, A.J., Kóspál, A., Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Torra, F., Laizeau, P., Lambert, S., Lanza, A.F., Lasne, Y., Le Campion, J.-F., Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Torra, J., Liao, S., Licata, E.L., Lindstrøm, H.E.P., Lister, T.A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Madrero Pardo, P., Magdaleno Romeo, A., Brown, A.G.A., Managau, S., Mann, R.G., Manteiga, M., Marchant, J.M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Marín Pina, D., Marinoni, S., Marocco, F., Vallenari, A., Marshall, D.J., Polo, L. Martin, Martín-Fleitas, J.M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., Messina, S., Prusti, T., Michalik, D., Millar, N.R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., De Bruijne, J.H.J., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C.P., Musella, I., Nagy, Z., Noval, L., Arenou, F., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J.O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P.A., Pallas-Quintela, L., Panahi, A., Babusiaux, C., Payne-Wardenaar, S., Peñalosa Esteller, X., Penttilä, A., Pichon, B., Piersimoni, A.M., Pineau, F.-X., Plachy, E., Plum, G., Poggio, E., Prša, A., Creevey, O.L., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Rambaux, N., Ramos, P., Re Fiorentin, P., Regibo, S., Richards, P.J., Diaz, C. Rios, Ducourant, C., Ripepi, V., Riva, A., Rix, H.-W., Rixon, G., Robichon, N., Robin, A.C., Robin, C., Roelens, M., Rogues, H.R.O., Rohrbasser, L., Evans, D.W., Romero-Gómez, M., Royer, F., Ruz Mieres, D., Rybicki, K.A., Sadowski, G., Sáez Núñez, A., Sagristà Sellés, A., Sahlmann, J., Salguero, E., Samaras, N., Eyer, L., Sanchez Gimenez, V., Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J.C., Ségransan, D., Semeux, D., Guerra, R., Shahaf, S., Siddiqui, H.I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R.L., Snaith, O.N., Solano, E., Hutton, A., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I.A., Stephenson, C.A., Süveges, M., Surdej, J., Jordi, C., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M.B., Teixeira, R., Tolomei, L., Tonello, N., Torralba Elipe, G., Trabucchi, M., Tsounis, A.T., Luri, X., Turon, C., Ulla, A., Unger, N., Vaillant, M.V., Van Dillen, E., Van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Panem, C., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, L., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., Zwitter, T., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N.A., Bailer-Jones, C.A.L., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M.G., Van Leeuwen, F., Bakker, J., Cacciari, C., De Angeli, F., Fouesneau, M., Frémat, Y., Galluccio, L., Guerrier, A., Heiter, U., Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G.M., Sordo, R., Thévenin, F., Gracia-Abril, G., Altmann, M., Andrae, R., Audard, M., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Burgess, P.W., Busonero, D., Busso, G., Cánovas, H., Carry, B., Cellino, A., Cheek, N., Clementini, G., Damerdji, Y., De Teodoro, P., Nuñez Campos, M., Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J.
Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13-21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 μas yr-1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution.
Switchable Cavitation in Silicone Coatings for Energy-Saving Cooling and Heating
2020, Zhao, H., Sun, Q., Zhou, J., Deng, X., Cui, J.
Space cooling and heating currently result in huge amounts of energy consumption and various environmental problems. Herein, a switching strategy is described for efficient energy-saving cooling and heating based on the dynamic cavitation of silicone coatings that can be reversibly and continuously tuned from a highly porous state to a transparent solid. In the porous state, the coatings can achieve efficient solar reflection (93%) and long-wave infrared emission (94%) to induce a subambient temperature drop of about 5 °C in hot weather (≈35 °C). In the transparent solid state, the coatings allow active sunlight permeation (95%) to induce solar heating to raise the ambient temperature from 10 to 28 °C in cold weather. The coatings are made from commercially available, cheap materials via a facile, environmentally friendly method, and are durable, reversible, and patternable. They can be applied immediately to various existed objects including rigid substrates.
Modeling saltwater intrusion scenarios for a coastal aquifer at the German North Sea
2018, Schneider, A., Zhao, H., Wolf, J., Logashenko, D., Reiter, S., Howahr, M., Eley, M., Gelleszun, M., Wiederhold, H., Szymkiewicz, Adam, Sadurski, A., Jaworska-Szulc, B.
A 3d regional density-driven flow model of a heterogeneous aquifer system at the German North Sea Coast is set up within the joint project NAWAK (“Development of sustainable adaption strategies for the water supply and distribution infrastructure on condition of climatic and demographic change”). The development of the freshwater-saltwater interface is simulated for three climate and demographic scenarios. Groundwater flow simulations are performed with the finite volume code d3f++ (distributed density driven flow) that has been developed with a view to the modelling of large, complex, strongly density-influenced aquifer systems over long time periods.
Experimental and numerical model study of the limiting current in a channel flow cell with a cirvular electrode
2008, Fuhrmann, Jürgen, Zhao, H., Holzbecher, E., Langmach, H., Chojak, M., Halseid, R., Jusys, Z., Behm, R.J.
We describe first measurement in a novel thin-layer channel flow cell designed for the investigation of heterogeneous electrocatalysis on porous catalysts. For the interpretation of the measurements, a macroscopic model for coupled species transport and reaction, which can be solved numerically, is feasible. In this paper, we focus on the limiting current. We compare numerical solutions of a macroscopic model to a generalization of a Leveque-type asymptotic estimate for circular electrodes, and to measurements obtained in the aforementioned flow cell. We establish, that on properly aligned meshes, the numerical method reproduces the asymptotic estimate. Furthermore, we demonstrate, that the measurements are partially performed in the sub-asymptotic regime, in which the boundary layer thickness exceeds the cell height. Using the inlet concentration and the diffusion coefficient from literature, we overestimate the limiting current. On the other hand, the use of fitted parameters leads to perfect agreement between model and experiment.
Applications of 2D-Layered Palladium Diselenide and Its van der Waals Heterostructures in Electronics and Optoelectronics
2021, Wang, Y., Pang, J., Cheng, Q., Han, L., Li, Y., Meng, X., Ibarlucea, B., Zhao, H., Yang, F., Liu, H., Liu, H., Zhou, W., Wang, X., Rümmeli, M., Zhang, Y., Cuniberti, G.
The rapid development of two-dimensional (2D) transition-metal dichalcogenides has been possible owing to their special structures and remarkable properties. In particular, palladium diselenide (PdSe2) with a novel pentagonal structure and unique physical characteristics have recently attracted extensive research interest. Consequently, tremendous research progress has been achieved regarding the physics, chemistry, and electronics of PdSe2. Accordingly, in this review, we recapitulate and summarize the most recent research on PdSe2, including its structure, properties, synthesis, and applications. First, a mechanical exfoliation method to obtain PdSe2 nanosheets is introduced, and large-area synthesis strategies are explained with respect to chemical vapor deposition and metal selenization. Next, the electronic and optoelectronic properties of PdSe2 and related heterostructures, such as field-effect transistors, photodetectors, sensors, and thermoelectric devices, are discussed. Subsequently, the integration of systems into infrared image sensors on the basis of PdSe2 van der Waals heterostructures is explored. Finally, future opportunities are highlighted to serve as a general guide for physicists, chemists, materials scientists, and engineers. Therefore, this comprehensive review may shed light on the research conducted by the 2D material community.
The role of reactive reaction intermediates in two-step heterogeneous electro-catalytic reactions: a model study
2010, Fuhrmann, Jürgen, Zhao, H., Langmach, H., Seidel, Y.E., Jusys, Z., Behm, R.J.
Experimental investigations of heterogeneous electrocatalytic reactions have been performed in flow cells which provide an environment with controlled parameters. Measurements of the oxygen reduction reaction in a flow cell with an electrode consisting of an array of Pt nanodisks on a glassy carbon substrate exhibited a decreasing fraction of the intermediate $H_2O_2$ in the overall reaction products with increasing density of the nanodiscs. A similar result is true for the dependence on the catalyst loading in the case of a supported Pt/C catalyst thin-film electrode, where the fraction of the intermediate decreases with increasing catalyst loading. Similar effects have been detected for the methanol oxidation. We present a model of multistep heterogeneous electrocatalytic oxidation and reduction reactions based on an adsorption-reaction-desorption scheme using the Langmuir assumption and macroscopic transport equations. A continuum based model problem in a vertical cross section of a rectangular flow cell is proposed in order to explain basic principles of the experimental situation. It includes three model species A, B, C, which undergo adsorption and desorption at a catalyst surface, as well as adsorbate reactions from A to B to C. These surface reactions are coupled with diffusion and advection in the Hagen Poiseuille flow in the flow chamber of the cell. Both high velocity asymptotic theory and a finite volume numerical are used to obtain approximate solutions to the model. Both approaches show a behaviour similar to the experimentally observed. Working in more general situations, the finite volume scheme was applied to a catalyst layer consisting of a number of small catalytically active areas corresponding to nanodisks. Good qualitative agreement with the experimental findings was established for this case as well.