Search results for "conduct"
showing 10 items of 4412 documents
Coherence properties in superconducting flux qubits
The research work discussed in this thesis deals with the study of superconducting Josephson qubits. Superconducting qubits are solid-state artificial atoms which are based on lithographically defined Josephson tunnel junctions properties. When sufficiently cooled, these superconducting devices exhibit quantized states of charge, flux or junction phase depending on their design parameters. This allows to observe coherent evolutions of their states. The results presented can be divided into two parts. In a first part we investigate operations of superconducting qubits based on the quantum coherence in superconducting quantum interference devices (SQUID). We explain experimental data which ha…
Applications and non-idealities of submicron Al–AlOx–Nb tunnel junctions
2016
We have developed a technique to fabricate sub-micron, 0.6µm×0.6µm Al-AlOx-Nb tunnel junctions using a standard e-beam resist, angle evaporation and double oxidation of the tunneling barrier, resulting in high quality niobium, as determined by the the high measured values of the critical temperature TC ∼ 7.5 K and the gap ∆ ∼ 1.3 meV. The devices show great promise for local nanoscale thermometry in the temperature range 1 - 7.5 K. Electrical characterization of the junctions was performed at sub-Kelvin temperatures both with and without an external magnetic field, which was used to suppress superconductivity in Al and thus bring the junction into a normal-metal-insulator-superconductor (NI…
Vacuum-Deposited Cesium Tin Iodide Thin Films with Tunable Thermoelectric Properties
2022
Most current thermoelectric materials have important drawbacks, such as toxicity, scarceness, and peak operating temperatures above 300 °C. Herein, we report the thermoelectric properties of different crystalline phases of Sn-based perovskite thin films. The 2D phase, Cs2SnI4, is obtained through vacuum thermal deposition and easily converted into the black β phase of CsSnI3(B-β CsSnI3) by annealing at 150 °C. B-β CsSnI3is a p-type semiconductor with a figure of merit (ZT) ranging from 0.021 to 0.033 for temperatures below 100 °C, which makes it a promising candidate to power small electronic devices such as wearable sensors which may be interconnected in the so-called Internet of Things. T…
Implementing the 3-omega technique for thermal conductivity measurements
2013
Thermal conductivity of the constituent materials is one of the most important properties affecting the performance of micro- and nanofabricated devices. These devices often make use of thin films with thicknesses ranging from some nanometers to few micrometers. The thermal conductivity of thin films can be measured with the three-omega method. In three-omega technique a metal wire acting as a resistive heater is microfabricated on the sample. Alternating current passing through the metal heater at a frequency ω heats the sample periodically and generates oscillations in the resistance of the metal line at a frequency 2ω. The oscillating resistance component is coupled with the driving curr…
Thin film conductivity measurements of carbon nanotube hemicellulose complex
2014
Työssä mitattiin hiilinanoputkista ja hemiselluloosasta koostuvan läpinäkyvän ohutkalvon sähkönjohtavuutta. Materiaali on Nemcel Oy:n kehittämä. Valmistimme useita näytteitä erilaisia mittauksia varten ja testataksemme eri valmistusmenetelmiä. Valmistetun ohutkalvon merkittävimmät ominaisuudet ovat läpinäkyvyys ja hyvä sähkönjohtavuus. Valmistetut kalvot olivat pääasiassa läpinäkyviä, mikä edellytti kalvon ohuutta. Itse materiaali toimitettiin vesiliuoksena, jossa oli 1:1 hiilinanoputkia ja hemiselluloosaa. Kalvot valmistettiin joko spinnaamalla tai kuivattamalla yksittäisiä pisaroita pinnalle. Näytteet valmistettiin pintaoksidioidulle piille, johon oli tehty kultaelektrodit. Kalvoa kuvatti…
Overview of Power Electronic Switches: A Summary of the Past, State-of-the-Art and Illumination of the Future.
2020
As the need for green and effective utilization of energy continues to grow, the advancements in the energy and power electronics industry are constantly driven by this need, as both industries are intertwined for obvious reasons. The developments in the power electronics industry has over the years hinged on the progress of the semiconductor device industry. The semiconductor device industry could be said to be on the edge of a turn into a new era, a paradigm shift from the conventional silicon devices to the wide band gap semiconductor technologies. While a lot of work is being done in research and manufacturing sectors, it is important to look back at the past, evaluate the current progr…
Deposition of tin sulfide thin films from tin(iv) thiolate precursors
2001
AACVD (aerosol-assisted chemical vapour deposition) using (PhS)(4)Sn as precursor leads to the deposition of Sn3O4 in the absence of H2S and tin sulfides when H2S is used as co-reactant. At 450 degreesC the film deposited consists of mainly SnS2 while at 500 degreesC SnS is the dominant component. The mechanism of decomposition of (PhS)(4)Sn is discussed and the structure of the precursor presented.
Tipologías de consumidores de alcohol dentro de la práctica del botellón en tres ciudades españolas
2010
En este trabajo se entrevistó a 6.009 jóvenes que practican botellón (14-25 años) en tres ciudades de la Comunidad Valenciana, realizando un muestreo estratifi cado de centros de Secundaria, Bachiller,CF y Universidad. Se efectuó un análisis de conglomerados en dos fases con cada muestra con dos objetivos: identifi car tipologías de consumidores de alcohol en el botellón y realizar una validación cruzada de la solución obtenida. Las variables consideradas en los análisis fueron: sexo, grupo de edad (universitarios: U; estudiantes Secundaria: ES), realización o no de episodios intensivos de consumo, años practicando botellón y gramos de alcohol ingeridos. Los resultados muestran evidencia de…
Fomento de la interacción social (conducta prosocial): correlatos neurobiológicos en el Transtorno de Espectro Autista
2015
Recientemente se ha observado un enorme incremento en la prevalencia del Trastorno de Espectro Autista (TEA) cuyos síntomas nucleares están relacionados con el déficit marcado en la comunicación e interacción social. El objetivo del trabajo fue realizar una revisión de la literatura sobre los factores neurobiológicos implicados en el fomento de la conducta social (conducta prosocial) en el TEA, en la última década. Las hormonas y neurotransmisores más relevantes serían la oxitocina, la vasopresina, la serotonina, andrógenos y estrógenos. En cuanto a neuroanatomía y sistema neuronales destacan la ínsula anterior, la amígdala, la zona fronto-parietal, el giro fusiforme y el sistema de neurona…
High-Sensitivity Whispering Gallery Mode Humidity Sensor Based on Glycerol Microdroplet Volumetric Expansion
2021
We demonstrate a highly sensitive whispering gallery mode (WGM) relative humidity (RH) sensor based on a glycerol microdroplet. WGMs were excited using a 760 nm tunable semiconductor laser. We used free space coupling, which is effective when using a liquid resonator. A detailed analysis of different parameters influencing the sensor’s characteristics (sensitivity, hysteresis, resolution, stability, and temperature) is presented. The sensitivity of the sensor is one of the highest reported (2.85 nm/% RH in the range 50–70% RH with the resolution 1 × 10−4% RH). This type of humidity sensor has several advantages, such as high sensitivity, extended lifetime, good repeatability, and low cost, …