Search results for "Temperature"
showing 10 items of 3798 documents
Derivation of a Homogenized Two-Temperature Model from the Heat Equation
2014
This work studies the heat equation in a two-phase material with spherical inclusions. Under some appropriate scaling on the size, volume fraction and heat capacity of the inclusions, we derive a coupled system of partial differential equations governing the evolution of the temperature of each phase at a macroscopic level of description. The coupling terms describing the exchange of heat between the phases are obtained by using homogenization techniques originating from [D. Cioranescu, F. Murat: Coll\`ege de France Seminar vol. 2. (Paris 1979-1980) Res. Notes in Math. vol. 60, pp. 98-138. Pitman, Boston, London, 1982.]
Savaime sklindančios aukštatemperatūrinės sintezės būdu gautų aliuminio oksinitrido miltelių ir jų keramikų optinės savybės
2021
The reported study was funded by RFBR according to the Research Project No. 19-08-00655. V.P. acknowledges the State Research Program ‘Aug-stas enerģijas fizika un paātrinātāju tehnoloģijas’ (Projekta Nr. VPP-IZM-CERN-2020/1-0002). The Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the H2020-WIDESPREAD-01-2016-2017-Teaming Phase2 under Grant Agreement No. 739508, Project CAMART2.
Photoluminescence-Based Spatially Resolved Temperature Coefficient Maps of Silicon Wafers and Solar Cells
2020
In this article, we present a method to obtain implied open-circuit voltage images of silicon wafers and cells at different temperatures. The proposed method is then demonstrated by investigating the temperature coefficients of various regions across multicrystalline silicon wafers and cells from different heights of two bricks with different dislocation densities. Interestingly, both low and high temperature coefficients are found in dislocated regions on the wafers. A large spread of temperature coefficient is observed at regions with similar performance at 298 K. Reduced temperature sensitivity is found to be correlated with the increasing brick height and is exhibited by both wafers and…
A Novel Method for Characterizing Temperature Sensitivity of Silicon Wafers and Cells
2019
In this paper, we present a novel method to obtain temperature dependent lifetime and implied-open-circuit voltage (iV OC ) images of silicon wafers and solar cells. First, the method is validated by comparing the obtained values with global values acquired from lifetime measurements (for wafers) and current-voltage measurements (for cells). The method is then extended to acquire spatially resolved images of iV OC temperature coefficients of silicon wafers and cells. Potential applications of the proposed method are demonstrated by investigating the temperature coefficients of various regions across multi-crystalline silicon wafers and cells from different heights of two bricks with differe…
Bandgap behavior and singularity of the domain-induced light scattering through the pressure-induced ferroelectric transition in relaxor ferroelectri…
2018
[EN] In this letter, we have investigated the electronic structure of A(x)Ba(1-x)Nb(2)O(6) relaxor ferroelectrics on the basis of optical absorption spectroscopy in unpoled single crystals with A = Sr and Ca under high pressure. The direct character of the fundamental transition could be established by fitting Urbach's rule to the photon energy dependence of the absorption edge yielding bandgaps of 3.44(1) eV and 3.57(1) eV for A = Sr and Ca, respectively. The light scattering by ferroelectric domains in the pre-edge spectral range has been studied as a function of composition and pressure. After confirming with x-ray diffraction the occurrence of the previously observed ferroelectric to pa…
Modelling of expected B, C, N and O Lyman-α line intensities emitted from W7-X plasmas and measured by means of the W7-X light impurity monitor system
2021
AbstractThe “C/O Monitor” for Wendelstein 7-X (W7-X) is a dedicated light impurity XUV spectrometer intended to measure Lyman-α transitions of hydrogen-like ions of four low-Z impurities—boron (4.9 nm), carbon (3.4 nm), nitrogen (2.5 nm) and oxygen (1.9 nm). Since the discussed diagnostic will deliver continuous information about the line intensities, it is crucial to understand the origin of the obtained signals with respect to the experimental plasma conditions (electron temperature and density). This, however, might be difficult because of the broad acceptance angle of the spectrometer and irregular shape of the plasma edge or SOL where the radiation is expected to mostly come from, depe…
Recent improvements on micro-thermocouple based SThM
2017
The scanning thermal microscope (SThM) has become a versatile tool for local surface temperature mapping or measuring thermal properties of solid materials. In this article, we present recent improvements in a SThM system, based on a micro-wire thermocouple probe associated with a quartz tuning fork for contact strength detection. Some results obtained on an electrothermal micro-hotplate device, operated in active and passive modes, allow demonstrating its performance as a coupled force detection and thermal measurement system.
Effects of Thermal Neutron Irradiation on a Self-Refresh DRAM
2020
International audience; In this study, static and dynamic test methods were used to define the response of a self-refresh DRAM under thermal neutron irradiation. The neutron-induced failures were investigated and characterized by event cross-sections, soft-error rate and bitmaps evaluations, leading to an identification of permanent and temporarily stuck cells, block errors, and single-bit upsets.
Space charge accumulation in undersea HVDC cables as function of heat exchange conditions at the boundaries – water-air interface
2020
Transmission lines with undersea HVDC cables are an interesting technological solution for the supply of electrical energy to islands. The accumulation of space charge inside the dielectric layer of a HVDC cable is one of the most important element to consider in its design and during operation. The formation of space charge is due to various factors including the high dependence on the temperature of the electrical conductivity of the insulation and the establishment of a thermal gradient under load conditions. This research is focused on the space charge accumulation phenomenon around a section of a HVDC cable half dipped in water and half in air. Due to the high difference in thermal con…
ABSOLUTE THERMOELECTRIC POWER OF Pb–Sn ALLOYS
2011
International audience; In this work, absolute thermoelectric power (ATP) of Pb, Sn, Pb-20 wt.% Sn, Pb-40 wt.% Sn, Pb-60 wt.% Sn, Pb-80 wt.% Sn are measured. Measurements are performed in a temperature gradient furnace from 20 degrees C to 500 degrees C, for both solid and liquid states. Temperatures are measured with T-type copper-constantan thermocouples, while voltage signal between copper electrodes of those thermocouples is recorded in order to calculate ATP of the sample metal.