1,374,497 research outputs found
Heat capacity measurements of Sr₂RuO₄ under uniaxial stress
Get PDFThe most-discussed pairing symmetry in Sr₂RuO₄ is chiral p-wave, ₓ ± [sub], whose degeneracy is protected by the lattice symmetry. When the lattice symmetry is lowered by the application of a symmetry-breaking field, the degeneracy can be lifted, potentially leading to a splitting of the superconducting transition. To lift the degeneracy, the symmetry breaking field used in this study is uniaxial stress. Uniaxial stress generated by a piezo-electric actuator can continuously tune the electronic structure and in situ lower the tetragonal symmetry in Sr₂RuO₄.
Previous studies of magnetic susceptibility and resistivity under uniaxial stress have revealed that there is a strong peak in T[sub]c when the stress is applied along the a-axis of Sr₂RuO₄. In addition, it
has been proposed that the peak in T[sub]c coincides with a van Hove singularity in the band structure, and measurements of [sub]₂ at the maximum T[sub]c indicate the possibility of an even parity condensate for Sr₂RuO₄ at the peak in T[sub]c.
In this thesis, the heat capacity approach is used to study the thermodynamic behavior of Sr₂RuO₄ under uniaxial stress applied along the crystallographic a-axis of Sr₂RuO₄. The first thermodynamic evidence for the peak in T[sub]c is obtained, proving that is a bulk property. However, the experimental data show no clear evidence for splitting of the superconducting transition; only one phase transition can be identified within the experimental resolution. The results impose strong constraints on the existence of a second phase transition, i.e. the size of the second heat capacity jump would be small or the second T[sub]c would have to be very close to the first transition. In addition to these results, I will present heat capacity data from the normal state of Sr₂RuO₄. The experimental results indicate that there is an enhancement of specific heat at the peak in T[sub]c, consistent with the existence of the van Hove singularity. The possibility of even parity superconductivity at the maximum T[sub]c has also been investigated. However, the heat capacity measurements are shown to be relatively insensitive to such a change, so it has not been possible to obtain strong and unambiguous evidence for whether it takes place or not
Fabbisogni energetici per edifici caratterizzanti il terziario in Italia: aspetti termici ed illuminotecnici
Get PDFIl presente lavoro verte sull'individuazione di benchmark di fabbisogno energetico per edifici di riferimento con destinazione d'uso non-residenziale. In particolare, si intende fornire profili tipo di domanda energetica per l'illuminazione artificiale, al fine di valutarne l'effetto sui profili di fabbisogno di energia per la climatizzazione estiva ed invernale, nonché di individuare le variabili che maggiormente incidono sulla loro determinazione. Per giungere a questi risultati, ci si avvale dell'uso di programmi informatici di simulazione dinamica riconosciuti ed impiegati a livello scientifico, in ambito europeo ed extraeuropeo (Energy Plus). La ricerca viene condotta sotto vari aspetti: architettonico, energetico e ambientale. Il primo obiettivo, partendo dalle indicazioni bibliografiche, legislative e normative, è quello di caratterizzare in modo univoco gli edifici di riferimento per le varie destinazioni d'uso oggetto di analisi: edifici per l'istruzione, ed edifici terziari. Gli edifici di riferimento intendono costituire archetipi rappresentativi del patrimonio edilizio italiano. Il secondo obiettivo è di tipo energetico: si intende definire profili tipo di domanda energetica per l'illuminazione artificiale degli ambienti. Si intendono inoltre valutare contestualmente i fabbisogni energetici netti per il riscaldamento e il raffrescamento degli ambienti. L'obiettivo finale è riuscire a determinare le migliori soluzioni progettuali per la minimizzazione del fabbisogno di energia connesso all'illuminazione, in relazione alle destinazioni d'uso dei differenti edifici, nonché le variabili che più incidono per indirizzare al meglio le attenzioni progettuali in caso di nuova realizzazione. Il presente lavoro, dopo un primo inquadramento generale in cui si delinea quello che è lo stato dell'arte della valutazione dei fabbisogni energetici e della ricerca scientifica in materia di illuminazione artificiale di ambienti non residenziali, passa poi ad indagare il significato di archetipo e a definire degli archetipi edilizi per il patrimonio immobiliare costruito a destinazione d'uso scolastica e terziaria. Successivamente vengono descritti i modelli di calcolo impiegati e sono dettagliati i dati di input impiegati per la loro definizione. Sono infine esplicati i risultati ottenuti, con individuazione dei valori di benchmark energetico per gli archetipi edilizi scolastici e terziari, e con l'analisi di quelle che sono le grandezze maggiormente influenti sul fabbisogno energetico per illuminazion
Fabrication of 3D Core–Shell Multiwalled Carbon Nanotube@RuO<sub>2</sub> Lithium-Ion Battery Electrodes through a RuO<sub>2</sub> Atomic Layer Deposition Process
No full textPushing lithium-ion battery (LIB) technology forward to its fundamental scaling limits requires the ability to create designer heterostructured materials and architectures. Atomic layer deposition (ALD) has recently been applied to advanced nanostructured energy storage devices due to the wide range of available materials, angstrom thickness control, and extreme conformality over high aspect ratio nanostructures. A class of materials referred to as conversion electrodes has recently been proposed as high capacity electrodes. RuO<sub>2</sub> is considered an ideal conversion material due to its high combined electronic and ionic conductivity and high gravimetric capacity, and as such is an excellent material to explore the behavior of conversion electrodes at nanoscale thicknesses. We report here a fully characterized atomic layer deposition process for RuO<sub>2</sub>, electrochemical cycling data for ALD RuO<sub>2</sub>, and the application of the RuO<sub>2</sub> to a composite carbon nanotube electrode scaffold with nucleation-controlled RuO<sub>2</sub> growth. A growth rate of 0.4 Å/cycle is found between ∼210–240 °C. In a planar configuration, the resulting RuO<sub>2</sub> films show high first cycle electrochemical capacities of ∼1400 mAh/g, but the capacity rapidly degrades with charge/discharge cycling. We also fabricated core/shell MWCNT/RuO<sub>2</sub> heterostructured 3D electrodes, which show a 50× increase in the areal capacity over their planar counterparts, with an areal lithium capacity of 1.6 mAh/cm<sup>2</sup>
Single carbon fiber decorated with RuO 2 nanorods as a highly electrocatalytic sensing element
No full textWe demonstrate highly efficient electocatalytic activities of single crystalline RuO 2 nanorods grown on carbon fiber (CF), i.e., RuO 2 nanorod-CF hybrid microelectrode, prepared by a simple thermal annealing process from the Ru(OH) 3 precursor at 300 °C. The general electrochemical activity of a RuO 2 nanorod-CF microelectrode represents faster electron transfer for the [Fe(CN) 6] 3-/4- couple than that of the bare CF microelectrode which are confirmed from the cyclic voltammetry (CV) measurement. Also, the amperometric response for the H 2O 2 oxidation is remarkably facilitated at the RuO 2 nanorod-CF microelectrode by not only the enlarged surface area but the high electrocatalytic activity of the RuO 2 nanorod material itself. Furthermore, a single microelectrode of RuO 2 nanorod-CF exhibits the superior tolerance to Cl - ion poisoning unlike Pt-based electrocatalysts, indicating the promising sensor candidate in physiological conditions. © 2012 American Chemical Society
Not for Zhao Shao-Ruo
No full textIn this collection, the artist has placed his name in red text over various subjects ranging from a set dinner table to a pornographic image and then promptly crossed it out. The artist had been influence by artists like Marcel Duchamp and Andy Warhol throughout his career. In 1989, Zhao was imprisoned after being involved in pro-democracy movements. This imprisonment lasted about one year until 1990. He then was arrested again in 1994 for fifty days. He escaped to Hong Kong in 1996 and moved with his wife to Finland in 1997. The title Not for Zhao Shao-Ruo and the crossing out of his name may be a reference to his time in prison where he did not have access to many pleasures. Furthermore, posters announcing death penalty declarations often had the names of the prisoner crossed out. Therefore, this artwork may be making a further negative statement. (Nicole Wang \u2726).https://digital.kenyon.edu/zhou/1614/thumbnail.jp
A combined experimental and theoretical study of RuO₂/TiO₂ heterostructures as a photoelectrocatalyst for hydrogen evolution
No full textWe report a joint experimental and theoretical study of RuO₂/TiO₂ heterostructures. In the experimental section, mesoporous RuO₂/TiO₂ heterostructures were prepared by impregnation of mesoporous TiO₂ nanoparticles which were synthesized from a new precursor, Na₂[Ti(C₂O₄)₃], in an aqueous solution of ruthenium(III) chloride followed by calcination at 300 °C. Using various techniques, the prepared TiO2 and RuO₂/TiO₂ heterostructures were extensively characterized. The photoelectocatalytic application of the as-prepared heterostructures was then investigated toward the hydrogen evolution reaction (HER). The results illustrated that RuO₂ is dispersed uniformly on the TiO₂ surface. The loading of RuO₂ on TiO₂ decreases the band gap energy and extends the absorption edge to the visible light region. This wide absorption extends the photoelectrocatalytic activity of RuO₂/TiO₂ heterostructures. To obtain a deeper understanding of the increase of the photoelectrocatalytic activity of RuO₂/TiO₂ heterostructures compared to pure TiO₂, theoretical calculations at the density functional theory (DFT) level were performed on some model clusters of pure TiO₂ and the RuO₂/TiO₂ heterostructure. The theoretical results elucidated that the recombination ratio of electron-hole pairs decreases effectively for RuO₂/TiO₂ compared to pure TiO₂
Ying jin 籯 金 par Li Ruo qiu 李 若 丘.
No full textLi Ruo qiu 李 若 丘. Ying jin 籯 金. HistoireNumérisation effectuée à partir d'un document original.Inachevé, préface et table des 14 premiers chapitres. Pour des mss. plus complets, cf. les Pelliot chinois 2966, 3650, 3907 et S. 5604. Titre initial : Ying jin yi bu 一 部, suivi de la mention : xiao shi shan chu shi Li Ruo qiu zhuan 小 室 山 處 士 李 若 丘 撰. Cf. PLTK , 1, j. 3, f. 10 a ; KTSL , p. 213. Écr. xing. Encre noire. 23 col., 9 col. par page, 14 à 18 car. par col. Marges tracées, sup. 0,9 à 1,2 cm, inf. 1,1 cm. Réglures
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