385 research outputs found
Synergistic Effect of Ligand-Cluster Structure and Support in Gold Nanocluster Catalysts for Selective Hydrogenation of Alkynes
No full text<h2>Data for the research article titled: "Synergistic Effect of Ligand-Cluster Structure and Support in Gold Nanocluster Catalysts for Selective Hydrogenation of Alkynes"</h2>
<p>Data used in the <a href="https://doi.org/10.1039/D4NR03865G">research article</a> and its supporting information. The paper was published in the Nanoscale journal by RSC.</p>
<h3>Authors</h3>
<p>Rares, Banu, Adea Loxha, Nicole Müller, Stylianos Spyroglou, Egon Erwin Rosenberg, A.<br>Eduardo Palomares, Fernando Rey, Carlo Marini, Noelia Barrabés∗</p>
<h3>Funding</h3>
<p>FWF via grant Elise Richter (V831-N); by the Spanish National Research Council for the project i-LINK 2023(ILINK23067) and the COST Action CA21101 COSY. We thank ALBA synchrotron for the beamtime. </p>
<h3>Context and methodology</h3>
<ul>
<li>In this article we report on the use of supported gold nanoclusters in the selective hydrogenation of alkynes to alkenes and investigate the support and pretreatment effect.</li>
<li>The dataset serves as a public resource and contains the data used in the manuscript and its supporting information.</li>
<li>The data was acquired by using different analytical methods, including various spectroscopies, and chromatographies.</li>
</ul>
<h3>Technical details</h3>
<ul>
<li>The files uploaded contain the measured XAFS, gas-chromatography, XRD, UV-Vis and MALDI-MS.</li>
<li>The OPJU files are graphs and can be opened with the <a href="https://en.wikipedia.org/wiki/Origin_(data_analysis_software)">Origin</a> software</li>
</ul>
Note sur les Hyménoptères Tenthredoïdes (XV). 29. Tenthrèdes rares ou nouvelles pour la France
No full textThe author reports captures of some rare sawflies, one of which is new in France : Pristiphora anderschi (Zaddach).L'auteur signale la capture de quelques Symphytes rares dont un nouveau pour la France : Pristiphora anderschi (Zaddach).Chevin Henri. Note sur les Hyménoptères Tenthredoïdes (XV). 29. Tenthrèdes rares ou nouvelles pour la France. In: Bulletin mensuel de la Société linnéenne de Lyon, 74ᵉ année, n°3, mars 2005. pp. 72-80
Gold Nanocluster als homogene und heterogene Katalysatoren für selektive Hydrierung
Full text linkHydrierungsreaktionen sind ein wichtiger Bestandteil einer Vielzahl von Industrien in der heutigen Welt, von der Öl- und Gasindustrie bis hin zu grÖsen Pharmakonzernen. Aus diesem Grund wurde viel Forschung in die Entwicklung hocheffizienter Katalysatoren gesteckt, wobei traditionell Metalle der Platingruppe verwendet werden. Obwohl mit den Katalysatoren, die hohe Umwandlungs- und Selektivitätsraten aufweisen, hervorragende Ergebnisse erzielt wurden, bleiben bestimmte Probleme bestehen. Um hohe Selektivitätsniveaus zu erreichen, müssen die Katalysatoren häufig modifiziert oder vergiftet werden, was die Katalyse weniger effizient macht. Darüber hinaus fehlt ein wirkliches Verständnis des katalytischen Prozesses auf atomarer Ebene. Aus diesem Grund ist es notwendig, neue M ̈glichkeiten zu erkunden. Ligandengeschützte Goldnanocluster sind eine relativ neue Klasse atomar präziser Materialien, deren Eigenschaften in hohem Mäse einstellbar sind. Es hat sich gezeigt, dass die Wahl der Liganden, wie Thiolate oder Phosphine, die Struktur, Stabilität und Anwendbarkeit von Goldnanoclustern mäsgeblich beeinflusst. Eine vielversprechende Anwendung für diese Metallnanocluster ist die Katalyse, sowohl in homogenen als auch heterogenen Systemen, wo sie ideale, wohldefinierte aktive Zentren zur Aufklärung der Struktur-Reaktivitäts-Beziehung bereitstellen. In dieser Arbeit wurden Goldnanocluster bei der heterogenen Semihydrierung von Alkinen und der homogenen Reduktion von Ketonen zu Alkoholen getestet. Untersucht wurden die Auswirkungen von Ligandentypen, Ligandenpopulationen um den Metallkern, ihre Wechselwirkungen mit Trägern sowie die Auswirkung der Vorbehandlung. Es wurden starke Ligand-Träger-Wechselwirkungen beobachtet, einschließlich der Migration der Liganden zu Oxidoberflächen, wodurch neue aktive Zentren entstanden, sowie ein deutlicher Einfluss der Vorbehandlung. Im homogenen System wurde der Effekt der Metall-Ligand-Grenzfläche durch ihren Einfluss auf die katalytische Aktivität sichtbar. Die Ergebnisse zeigen, wie wichtig es ist, den Katalysator auf atomarer Ebene zu verstehen und alle strukturellen Aspekte beim Entwurf und der Optimierung eines katalytischen Systems zu berücksichtigen, wodurch Goldnanocluster ideale Kandidaten für solche Anwendungen sind.Hydrogenation reactions are an important part of a multitude of industries in today's world, ranging from oil and gas to big pharma. Due to this, a lot of research has gone into designing highly efficient catalysts, with platinum group metals being traditionally used. While great results have been achieved, with the catalysts showing high conversion and selectivity rates, certain problems remain. In order to reach high selectivity levels, the catalysts must often be modified or poisoned, making the catalysis less efficient. Furthermore, a true understanding of the catalytic process at an atomic level is missing. Because of this, it is necessary to explore new possibilities. Ligand protected gold nanoclusters are a relatively novel class of atomically precise materials, which properties are highly tuneable. It has been shown that the choice of ligands, such as thiolates or phosphines, significantly influences the structure, stability and applicability of gold nanoclusters. One promising application for these metal nanoclusters is catalysis, both in homogeneous and heterogeneous systems, where they provide ideal, well-defined active sites to elucidate the structure-reactivity relationship. In this thesis, gold nanoclusters were tested in the heterogeneous semihydrogenation of alkynes and the homogeneous reduction of ketones to alcohols. The effects of ligand types, ligand populations around the metal core, their interactions with supports, as well as the effect of pretreatment were investigated. Strong ligand-support interactions were observed, including ligand migration to oxide surfaces, creating new active sites, as well as a clear influence of pretreatment. In the homogeneous system, the effect of metal ligand interface became visible, through its impact on the catalytic activity. The results show the importance of understanding the catalyst at an atomic level and considering all structural aspects when designing and optimizing a catalytic system, placing gold nanoclusters as ideal candidates for such applications
Note sur les Hyménoptères Tenthrédoïdes (XIV). 28. Tenthrèdes rares ou nouvelles pour la France
No full textNote on the Hymenoptera Symphyta (XIV).
28. Rare or new sawfly species from France.
The author indicates capture of some sawflies rare or new to France (Cephalcia fallenii Dalman, Pamphilius thorwaldi Kontuniemi, Dolerus bensoni Muller, Tenthredopsis thornleyi Konow).L'auteur signale la capture de quelques Symphytes rares ou nouveaux pour la France (Cephalcia fallenii Dalman, Pamphilius thorwaldi Kontuniemi, Dolerus bensoni Muller, Tenthredopsis thornleyi Konow).Chevin Henri. Note sur les Hyménoptères Tenthrédoïdes (XIV). 28. Tenthrèdes rares ou nouvelles pour la France. In: Bulletin mensuel de la Société linnéenne de Lyon, 66ᵉ année, n°8, octobre 1997. pp. 216-224
Internal friction investigation of phase transformation in nearly stoichiometric LaMnO3+δ
Full text linkRhombohedral LaMnO3+δ powders, prepared by two different soft chemistry routes (co-precipitation and hydrothermal synthesis), are sintered at 1400 °C for 2 h in air. Measurements of internal friction Q−1(T) and shear modulus G(T), at low frequencies from −180 to 700 °C under vacuum, evidence three structural transitions of nearly stoichiometric orthorhombic LaMnO3+δ. The first one, at 250 or 290 °C, depending on the processing followed, is associated to either a Jahn–Teller structural transition or a phase transformation from orthorhombic to pseudo-cubic. The second one at 610 or 630 °C is related to a phase transformation from pseudo-cubic or orthorhombic to rhombohedral. Below the Neel temperature, around −170 °C, a relaxation peak could be associated, for samples prepared according to both processing routes, to the motion of Weiss domains
Note sur les Hyménoptères Tenthrédoides (X). 22. Quelques espèces rares ou nouvelles pour la France
No full textNote on the Hymenoptera Tenthredoidea 22. Some rare or new species from France. — The author indicates captures of some sawflies (Sterictiphora gastrica Klug, Monoctenus obscuratus Hartig. Paracharactus hyalinus Konow, Sterigmos ventralis Panzer, Pachynematus calcicola Benson) or new from France (Xyela curva Benson, Cephas infuscatus Ed. André, Empria minuta Lindqvist, Hoplocampa prunicola Benson, Pristiphora thalictri Kriechbaumer).L'auteur signale la capture de quelques Symphytes rares (Sterictiphora gastrica Klug, Monoctenus obscuratus Hartig, Paracharactus hyalinus Konow, Sterigmos ventralis Panzer, Pachynematus calcicola Benson) ou nouveaux pour la France (Xyela curva Benson, Cephus infuscatus Ed. André, Empria minuta Lindqvist, Hoplocampa prunicola Benson, Pritiphora thalictri Kriechbaumer).Chevin Henri. Note sur les Hyménoptères Tenthrédoides (X). 22. Quelques espèces rares ou nouvelles pour la France. In: Bulletin mensuel de la Société linnéenne de Lyon, 53ᵉ année, n°4, avril 1984. pp. 157-159
Archived film analysis and restoration
No full textThe progressive degradation of current film archives poses a serious threat to the preservation of our cultural and technical heritage. Digitization and digital restoration are currently the most viable solutions for the long term preservation and high quality restoration of filmed material. They also open the path for more effective search, reuse and distribution of the archived content. This thesis covers various aspects of digital restoration applied to archived film. The main focus here lies on blotch restoration in conditions of difficult object motion. The topics covered in this thesis include: - Classification of complex events in degraded image sequences, in order to separate the temporally impulsive events into artefact areas and areas with difficult motion. - Spatial restoration of blotches (dirt, or gelatin loss), through virtual reconstruction of object edges followed by guided inpainting or constrained texture synthesis. - Spatiotemporal restoration of blotches by combining spatial edge-based restoration and temporal restoration techniques. - Restoration of the vinegar syndrome (combined with emulsion melting), a special type of artefact that represents one of the main problems of current film archives. - Object tracking, which can be used for enhancing the results of the motion estimation step that is performed in most temporal restoration algorithms. Extensive tests were performed, in order to validate the proposed algorithms and to show their readily application to real world cases.Electrical Engineering, Mathematics and Computer Scienc
Statut actuel des Vertébrés rares et menacés des Galapagos
No full textDuring a 14 months stay in the Galapagos islands the author was able to study the local distribution and the numbers of some of the scarcert endemic Vertebrates of the archipelago. His results show that the Fur-seal population reaches up to about 4 000 heads, while they are about 2 000 breeding pairs of Albatrosses, 1 500 Penguins, 1 000 Flightless Cormorants and no more than 100 to 150 Flamingoes. One thousand Tortoises at least were counted on Indefatigable. Notes are also given on the breeding seasons and clutch-size of various birds.Lévêque Raymond. Statut actuel des Vertébrés rares et menacés des Galapagos. In: La Terre et La Vie, Revue d'Histoire naturelle, tome 17, n°4, 1963. pp. 397-430
Note faunistique concernant quelques espèces de Tenthredinidae rares ou nouvelles pour la France (Hymenoptera, Symphyta)
No full textFaunistic note concerning some Tenthredinidae species rare or new to France (Hymenoptera, Symphyta).
In this note, the author gives precisions about geographic distribution of some Tenthredinidae rare in France. He also indicates capture of 11 species new to France : Amauronematus enslini Lindqvist, A. hartigi Saarinen, Brachycoluma longiserra (Malaise), Dolerus pachycerus Hartig, D. zhelochovtsevi Heidemaa, Euura elaeagnos Kopelke, E. cinereae Kopelke, E. purpureae Kopelke, E. venusta (Brischke), Polynematus infirmus (Forster), Pontania samolad Malaise.Dans cette note, l'auteur apporte des précisions concernant la répartition géographique de certaines espèces de Tenthredinidae considérées comme rares en France. Il cite également la capture de 11 espèces nouvelles pour la France : Amauronematus enslini Lindqvist, A. harîigi Saarinen, Brachycoluma longiserra (Malaise), Dolerus pachyce-rus Hartig, D. zhelochovtsevi Heidemaa, Euura elaeagnos Kopelke, E. cinereae Kopelke, E. purpureae Kopelke, E. venusta (Brischke), Polynematus infirmus (Forster), Pontania samolad Malaise.Lacourt Jean. Note faunistique concernant quelques espèces de Tenthredinidae rares ou nouvelles pour la France (Hymenoptera, Symphyta). In: Bulletin mensuel de la Société linnéenne de Lyon, 70ᵉ année, n°9, novembre 2001. pp. 217-233
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