Search results for "Applied Physic"
showing 10 items of 1228 documents
A Compact SPICE Model for Organic TFTs and Applications to Logic Circuit Design
2016
This work introduces a compact DC model developed for organic thin film transistors (OTFTs) and its SPICE implementation. The model relies on a modified version of the gradual channel approximation that takes into account the contact effects, occurring at nonohmic metal/organic semiconductor junctions, modeling them as reverse biased Schottky diodes. The model also comprises channel length modulation and scalability of drain current with respect to channel length. To show the suitability of the model, we used it to design an inverter and a ring oscillator circuit. Furthermore, an experimental validation of the OTFTs has been done at the level of the single device as well as with a discrete-…
Synthesis and luminescent properties of Mn-doped alpha-tricalcium phosphate
2021
This project has received funding from European Social Fund (project No 09.3.3-LMT-K-712-19-0069) under grant agreement with the Research Council of Lithuania (LMTLT). Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART². The World Federation of Scientists is highly acknowledged for the National Scholarship to AZ. © 2021. This work is licensed under a CC BY-NC-ND 4.0 license.
UV light induced processes in pure and doped AlN ceramics
2021
The present research has been sponsored by the Latvian Council of Science , Grant No. lzp-2018/1-0361 “Research of luminescence mechanisms and dosimeter properties in prospective nitrides and oxides using TL and OSL methods “; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 73950 , project CAMART 2
Status of new 18 GHz ECRIS HIISI
2018
A new 18 GHz ECR ion source HIISI is under commissioning at the Accelerator Laboratory at the University of Jyvaskyla (JYFL). The main purpose of HIISI is to produce high-energy beam cocktails, e.g. Xe44+, for radiation effects testing of electronics with the K130 cyclotron. The initial commissioning results in 18+14 GHz operation with oxygen, argon and xenon are reported. The beam currents are compared to those produced by reference ion sources (JYFL 14 GHz ECRIS, GTS and SuSI). At the moment (October 2017) 560 µA of O6+ and 310 µA of Ar13+, for example, have been reached with HIISI at 2.3 kW total power.A new 18 GHz ECR ion source HIISI is under commissioning at the Accelerator Laboratory…
Vanadium Carbide Dissolution during Austenitisation of a Model Microalloyed FeCV Steel
2005
High performance commercial micro alloyed steels contain elements such as vanadium, which leads to a fine dispersion of vanadium carbide precipitates. The precipitation state, in terms of volume fraction and size distribution, plays a significant role in final mechanical properties of the material. Different austenitisation heat treatments were performed on a model ternary alloy FeCV. Precipitation states were characterised combining different experimental techniques. TEM was used to identify the chemical composition of observed precipitates. ICP mass spectroscopy was performed to measure the volume fraction of precipitates. The size distribution was studied by SEM. Results are characterist…
Reliability of PEA Measurement in Presence of an Air Void Defect
2020
This paper deals with the reliability of the Pulsed Electro-Acoustic (PEA) technique in the case of a specimen containing an air layer. The first approach to this study has been proposed by the authors in previously published works. In these papers, the mathematical description, the PEA cell simulation model, and some experimental tests have been reported. In this work, a more accurate description of the acoustic wave behavior within the PEA cell and specimen with and without an air layer is given. Moreover, the comparison between simulation and experimental tests for both cases (specimen with and without air layer) allowed the validation of the previously developed PEA cell simulation mode…
Low-temperature atomic layer deposition of SiO2/Al2O3 multilayer structures constructed on self-standing films of cellulose nanofibrils
2018
In this paper, we have optimized a low-temperature atomic layer deposition (ALD) of SiO 2 using AP-LTO® 330 and ozone (O 3 ) as precursors, and demonstrated its suitability to surface-modify temperature-sensitive bio-based films of cellulose nanofibrils (CNFs). The lowest temperature for the thermal ALD process was 80°C when the silicon precursor residence time was increased by the stop-flow mode. The SiO 2 film deposition rate was dependent on the temperature varying within 1.5–2.2 Å cycle −1 in the temperature range of 80–350°C, respectively. The low-temperature SiO 2 process that resulted was combined with the conventional trimethyl aluminium + H 2 O process in order to prepare thin mul…
Investigation on Metal–Oxide Graphene Field-Effect Transistors With Clamped Geometries
2019
In this work, we report on the design, fabrication and characterization of Metal-Oxide Graphene Field-effect Transistors (MOGFETs) exploiting novel clamped gate geometries aimed at enhancing the device transconductance. The fabricated devices employ clamped metal contacts also for source and drain, as well as an optimized graphene meandered pattern for source contacting, in order to reduce parasitic resistance. Our experimental results demonstrate that MOGFETs with the proposed structure show improved high frequency performance, in terms of maximum available gain and transition frequency values, as a consequence of the higher equivalent transconductance obtained.
On the mechanisms involved in the tensile strength of a dissimilar Ti6Al4V/316L laser welded assembly
2021
International audience; The aim of the present work is to analyze the thermomechanical behavior of dissimilar laser seams by means of FE modeling. The case of a Ti6Al4V/316L assembly with vanadium insert was considered. Effective mechanical properties of the main materials and cords were first estimated from NHT measurements. Modeling of the double pass laser welding process was performed first by considering shrinking of the two weld seams during manufacturing, to get the residual stress state in the welded assembly. Modeling of the tensile test was performed in a second step to study the assembly behavior during loading. In these modeling results, the mesh was the cross-section of the mic…
Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models
2014
International audience; A survey of recent contributions on three-dimensional grain-scale mechanical modelling of polycrystalline materials is given in this work. The analysis of material micro-structures requires the generation of reliable micro-morphologies and affordable computational meshes as well as the description of the mechanical behavior of the elementary constituents and their interactions. The polycrystalline microstructure is characterized by the topology, morphology and crystallographic orientations of the individual grains and by the grain interfaces and microstructural defects, within the bulk grains and at the inter-granular interfaces. Their analysis has been until recentl…