Search results for "TUNNEL"
showing 10 items of 576 documents
Ricerca sulla simulazione del funzionamento in regime vario di forni continui per la cottura di ceramiche e porcellane
2005
Patologie da movimenti ripetitivi degli arti superiori in un gruppo di cassiere di un supermercato palermitano
2010
Studio osservazionale su un gruppo di lavoratori esposti a fattori di rischio professionali per la "Sindrome del tunnel carpale".
2008
Ski jumping takeoff in a wind tunnel with skis.
2011
The effect of skis on the force–time characteristics of the simulated ski jumping takeoff was examined in a wind tunnel. Takeoff forces were recorded with a force plate installed under the tunnel floor. Signals from the front and rear parts of the force plate were collected separately to examine the anteroposterior balance of the jumpers during the takeoff. Two ski jumpers performed simulated takeoffs, first without skis in nonwind conditions and in various wind conditions. Thereafter, the same experiments were repeated with skis. The jumpers were able to perform very natural takeoff actions (similar to the actual takeoff) with skis in wind tunnel. According to the subjective feeling of the…
Superconducting tunnel junctions and nanorefrigeration using InAs nanowires
2017
Työssä selvitettiin menetelmää suprajohtavien kontaktien liittämiseksi ohuen eristekerroksen avulla vahvasti n-seostettuun puolijohtavaan InAs-nanolankaan. Lisäksi tutkittiin näin luotujen tunneliliitosten soveltamista nanolankojen elektronisen lämpötilan mittaukseen ja sen jäähdyttämiseen. Nanolangat oli kasvatettu epitaksiaalisesti kultananopartikkeleiden katalysoimina, ja suprajohtavat kontaktit valmistettiin niiden päälle käyttäen tavanomaisia mikrovalmistusmenetelmiä, elektronisuihkulitografiaa ja -höyrystystystä. Aluksi langan päälle höyrystettiin ohut kerros titaania ja paksumpi kerros alumiinimangaania, joka oksidoitiin in situ eristekerroksen luomiseksi, ja lopuksi lisättiin supraj…
Large-area SINIS tunnel junctions for cooling applications
2015
Työn aiheena on pinta-alaltaan suuret SINIS-tunneliliitokset ja niiden käyttö jäähdytyksessä. SINIS-tunneliliitos koostuu kahdesta normaalimetalli-eristesuprajohde (NIS) rakenteesta, jotka ovat kytkettynä toisiinsa sarjaankytkennällä. Tällaisia rakenteita voidaan käyttää jäähdytyksessä matalissa lämpötiloissa. Tämän mahdollistaa suprajohteille ominainen energia-aukko, joka tarkoittaa, että tietyillä energian arvoilla suprajohteessa ei ole sallittuja tiloja, joille elektronit voisivat asettua. Energia-aukko sijoittuu keskitetysti Fermi-energian E_F kohtaan, joka tarkoittaa että lämpötilassa T = 0 kaikki Fermi-energian alapuolella olevat tilat ovat miehitettyjä ja sen yläpuolella olevat tyhji…
Development of niobium-based superconducting junctions
2012
This thesis presents a review of publications which mainly focuses on the fabrication and performance of Nb-based normal metal-insulator-superconductor (NIS) tunnel junctions and superconductor-normal metal-superconductor (SNS) Josephson junctions at low temperatures. The Cu/AlOx-Al/Nb based NIS double tunnel junctions were successfully fabricated using conventional electron beam lithography combined with multi-angle thermal evaporation of metals in ultra high vacuum. The subgap characteristics of these junctions showed expected temperature dependence from 0.2 K to 5 K with a good thermometry sensitivity 0.2-0.3 mV/K. Signatures of small electronic cooling effects were observed near the Nb …
Normal-Metal–Insulator–Superconductor Tunnel Junction With Atomic-Layer-Deposited Titanium Nitride as Superconductor
2015
Spin-lattice relaxation of deuterated methyl groups: Implications of the pauli principle
1999
The high-field spin-lattice relaxation of deuterated methyl groups undergoing rotational tunneling is investigated theoretically. It is found that for systems showing a tunneling frequency comparable to accessible Larmor frequencies the relaxation to equilibrium of the Zeeman energy does not follow a simple exponential time dependence even in powdered samples due to a finite coupling to the relaxation of the tunneling system. This finding contrasts to the high-temperature behavior of reorienting methyl groups which undergo simple exponential relaxation. The nonexponentiality has its origin in the statistical coupling of the three deuteron spins due to the Pauli principle.
Applications of tunnel junctions in low-dimensional nanostructures
2009
This thesis concentrates on studies of AlOx based tunnel junctions and their feasibility for cooling, thermometry and strain sensing in suspended nanostructures. The main result of the thesis is cooling of one dimensional phonon modes of a suspended nanowire with normal metal insulator superconductor (NIS) tunnel junctions. Simultaneous cooling of both electrons and phonons was achieved, and the lowest phonon temperature reached in the system was 42 mK with an initial temperature of 100 mK. In addition, suspended devices show cooling still at a bath temperature of 600 mK. The observed thermal transport characteristics show, that the heat flow is limited by the scattering of phonons at the b…