Search results for "LEVEL"
showing 10 items of 3465 documents
Electrochemical Tantalum Oxide for Resistive Switching Memories
2017
Redox-based resistive switching memories (ReRAMs) are strongest candidates for the next-generation nonvolatile memories fulfilling the criteria for fast, energy efficient, and scalable green IT. These types of devices can also be used for selector elements, alternative logic circuits and computing, and memristive and neuromorphic operations. ReRAMs are composed of metal/solid electrolyte/metal junctions in which the solid electrolyte is typically a metal oxide or multilayer oxides structures. Here, this study offers an effective and cheap electrochemical approach to fabricate Ta/Ta2O5-based devices by anodizing. This method allows to grow high-quality and dense oxide thin films onto a metal…
Initial light-induced degradation study of multicrystalline modules made from silicon material processed through different manufacturing routes
2012
The paper presents results of initial lightinduced degradation (LID) of multicrystalline silicon photovoltaic (PV) modules made of crystalline silicon from different manufacturing processes. The modules were installed within the Sunbelt, in Hyderabad, India. Current-voltage (I–V) characteristics are measured and infra-red (IR) images of the modules are taken at regular intervals. A relationship of the IV degradation with the IR images is discussed. Results from laboratory LID tests at room temperature are performed parallel to the outdoor degradation of PV modules. It was found that the total LID, measured on the module level, after the initial 40 hours is similar for both materials resulti…
Efficiency comparison between SiC- and Si-based active neutral-point clamped converters
2015
This paper presents an efficiency comparison between silicon-carbide technology and silicon technology. In order to achieve this, the efficiency of an active neutral-point clamped converter built up with silicon carbide power-devices is compared with the efficiency of an active neutral-point clamped converter built up with silicon power-devices, under a particular operating mode and a particular selection of devices. Firstly, overall losses of both converters are estimated. Then, experimental tests are carried out to measure their overall losses and efficiency. Finally, experimental results are compared with the estimations to support the analysis. The efficiency of the SiC converter is hig…
Drying rate control in microwave assisted processing of sliced apples
2018
The most enhanced microwave systems for the preparation of quality-dehydrated fruits continuously adjust the power level in order to maintain the product temperature above a target value. As a result, typical drying curves that exhibit high drying rates in the middle stage are obtained. This can often lead to quality damage or undesirable changes on food colour and texture. In response to these issues, a microwave system is proposed that can realise drying processes keeping drying rates constant. This approach required a continuous temperature adjustment of the apple slices under test, whose temperature was detected by a computer-aided infrared thermography system. Since temperature correct…
Vertical osteoconductivity and early bone formation of titanium-zirconium and titanium implants in a subperiosteal rabbit animal model.
2013
Objectives The aim of this pilot study was to evaluate the vertical osteoconductive and osteointegrative dynamics around titanium–zirconium (TiZr) implants compared to titanium (Ti) implants. Materials and methods In a split-leg design, 12 TiZr-SLActive and 12 Ti-SLActive implants were inserted 3 mm above bone level in the proximal tibia of 12 rabbits. Full periosteal flaps were repositioned to cover the site. Specimens were obtained after 10, 20 and 30 days (each n = 4 per group). Histomorphometric measurements included percentage of linear bone fill (PLF; %), new marginal vertical bone height (VBH; mm) and vertical bone-to-implant contact (vBIC; %). Statistical analysis was performed with…
Correction: Variation of the Fermi level and the electrostatic force of a metallic nanoparticle upon colliding with an electrode.
2017
The nanoparticle potential varies with the distance from the electrode, and sometimes like attracts like.
Negative capacitance caused by electron injection through interfacial states in organic light-emitting diodes
2006
The negative capacitance frequently observed at low frequencies in organic light-emitting diodes (LEDs) is explained as a signature of sequential electron injection at the organic/metal interface first to states in the bandgap in the dipole layer and then to bulk states. The negative capacitance occurs when the interfacial states depart from equilibrium with the metal Fermi level due to an increasing rate of hopping to the bulk states. A simple kinetic model compares well with the experimental results and provides a new tool to investigate interfacial properties for improving the performance of organic LEDs.
Quantifiable analysis of the failure of advanced carbon fibre composite structures leading to improved safety factors
2022
Abstract The increasing use of advanced composite materials means that they must now be considered as major materials for a wide variety of structures some of which will be in service for decades. There is therefore an important need to be able to quantify damage accumulation leading to failure in these materials particularly as they are often used in extreme situations for which failure must be avoided. This review shows how damage accumulation in many major composite structures is dominated by fibre failure but that the viscoelastic nature of the matrix induces time effects including delayed failure. It is shown that damage accumulation can be quantitatively modelled using a multi-scale a…
Very low instability threshold in a three-level laser model with incoherent optical pumping
1997
Abstract The stability properties of a laser model based on a closed three-level atomic scheme with incoherent optical pumping are studied. Unexpectedly, the instability threshold can be very low approaching the lasing threshold for large unsaturated gain values.
Mathematical analysis of projection errors in “paralleling technique” with respect to implant geometry
2001
Abstract: “Standardized” radiographs acquired in paralleling technique serve for monitoring of marginal bone levels around endosseous implants. Under clinical conditions, parallel adjustment of the film to the implant is beset with great difficulties. A mathematical model matching clinical conditions was developed to evaluate projection geometry within an interval of clinically relevant angulations (± 10° from parallel position). Radiographs of two implants (Frialit 2, Friadent AG, Mannheim, Germany; Implant No. 1: ∅ 3.8 mm, length 10 mm; Implant No. 2: ∅ 6.5 mm, length 13 mm) were separately produced per angulation (2° increments) at one focus-object distance (FO=322.9 mm). Implant images …