scholarly journals Thermal Characterization of Low-Dimensional Materials by Resistance Thermometers

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1740 ◽  
Author(s):  
Yifeng Fu ◽  
Guofeng Cui ◽  
Kjell Jeppson
Keyword(s):  
Thermal Performance ◽  
Three Dimensional ◽  
Thermal Characterization ◽  
Resistance Thermometer ◽  
Light Emitting ◽  
Resistance Thermometers ◽  
Low Dimensional ◽  
Low Dimensional Materials ◽  
Boron Nitride Films

The design, fabrication, and use of a hotspot-producing and temperature-sensing resistance thermometer for evaluating the thermal properties of low-dimensional materials are described in this paper. The materials that are characterized include one-dimensional (1D) carbon nanotubes, and two-dimensional (2D) graphene and boron nitride films. The excellent thermal performance of these materials shows great potential for cooling electronic devices and systems such as in three-dimensional (3D) integrated chip-stacks, power amplifiers, and light-emitting diodes. The thermometers are designed to be serpentine-shaped platinum resistors serving both as hotspots and temperature sensors. By using these thermometers, the thermal performance of the abovementioned emerging low-dimensional materials was evaluated with high accuracy.

Thermal characterization of ABS-Graphene blended three dimensional printed functional prototypes for electro chemical energy storage

2018 ◽  
Vol 1 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Kamaljit Singh Boparai ◽  
Rupinder Singh
Keyword(s):  
Energy Storage ◽  
Structural Changes ◽  
Fused Deposition Modeling ◽  
Morphological Changes ◽  
Three Dimensional ◽  
Thermal Characterization ◽  
Chemical Energy ◽  
Flow Index ◽  
Fused Deposition

This study highlights the thermal characterization of ABS-Graphene blended three dimensional (3D) printed functional prototypes by fused deposition modeling (FDM) process. These functional prototypes have some applications as electro-chemical energy storage devices (EESD). Initially, the suitability of ABS-Graphene composite material for FDM applications has been examined by melt flow index (MFI) test. After establishing MFI, the feedstock filament for FDM has been prepared by an extrusion process. The fabricated filament has been used for printing 3D functional prototypes for printing of in-house EESD. The differential scanning calorimeter (DSC) analysis was conducted to understand the effect on glass transition temperature with the inclusion of Graphene (Gr) particles. It has been observed that the reinforced Gr particles act as a thermal reservoir (sink) and enhances its thermal/electrical conductivity. Also, FT-IR spectra realized the structural changes with the inclusion of Gr in ABS matrix. The results are supported by scanning electron microscopy (SEM) based micrographs for understanding the morphological changes.

scholarly journals Luminescence of SiO2-BaF2:Tb3+, Eu3+ Nano-Glass-Ceramics Made from Sol–Gel Method at Low Temperature

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 259
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Tomasz Goryczka ◽  
Ewa Pietrasik ◽  
Wojciech A. Pisarski
Keyword(s):  
Sol Gel ◽  
Three Dimensional ◽  
Glass Ceramics ◽  
Emission Spectra ◽  
Scanning Calorimetry ◽  
Light Emitting ◽  
Co Doping ◽  
Dsc Measurements ◽  
Decay Times

The synthesis and characterization of multicolor light-emitting nanomaterials based on rare earths (RE3+) are of great importance due to their possible use in optoelectronic devices, such as LEDs or displays. In the present work, oxyfluoride glass-ceramics containing BaF2 nanocrystals co-doped with Tb3+, Eu3+ ions were fabricated from amorphous xerogels at 350 °C. The analysis of the thermal behavior of fabricated xerogels was performed using TG/DSC measurements (thermogravimetry (TG), differential scanning calorimetry (DSC)). The crystallization of BaF2 phase at the nanoscale was confirmed by X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM), and the changes in silicate sol–gel host were determined by attenuated total reflectance infrared (ATR-IR) spectroscopy. The luminescent characterization of prepared sol–gel materials was carried out by excitation and emission spectra along with decay analysis from the 5D4 level of Tb3+. As a result, the visible light according to the electronic transitions of Tb3+ (5D4 → 7FJ (J = 6–3)) and Eu3+ (5D0 → 7FJ (J = 0–4)) was recorded. It was also observed that co-doping with Eu3+ caused the shortening in decay times of the 5D4 state from 1.11 ms to 0.88 ms (for xerogels) and from 6.56 ms to 4.06 ms (for glass-ceramics). Thus, based on lifetime values, the Tb3+/Eu3+ energy transfer (ET) efficiencies were estimated to be almost 21% for xerogels and 38% for nano-glass-ceramics. Therefore, such materials could be successfully predisposed for laser technologies, spectral converters, and three-dimensional displays.

scholarly journals Synthesis, Spectral, Structural and Thermal Characterization of Inorganic Crystal: Phenyl Trimethylammonium Tetrachlorocobaltate

2019 ◽  
Vol 31 (8) ◽  
pp. 1779-1784
Author(s):  
V. Mohanraj ◽  
R. Pavithra ◽  
M. Thenmozhi ◽  
R. Umarani
Keyword(s):  
Three Dimensional ◽  
Thermal Characterization ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
Evaporation Technique ◽  
Ft Ir ◽  
Thermal Stability Of ◽  
Ft Ir Spectroscopy

Phenyl trimethylammonium tetrachlorocobaltate, crystals were grown by slow evaporation technique. The crystal was bright, transparent. The three dimensional structure of the phenyl trimethylammonium tetrachlorocobaltate was obtained from single crystal X-ray diffraction studies. The molecule belongs to monoclinic crystal system with C2/c space group. The presence of functional groups and modes of vibrations were identified by FT-IR spectroscopy. 1H NMR spectroscopy was also used to characterise the compound and the thermal stability of the crystal was established by TGA/DT analysis. This work undergoes phase transition which makes the study interesting.

scholarly journals Optical and Thermal Analysis of Secondary Optics in Light Emitting Diodes’ Packaging: Analysis of MR16 Lamp

2021 ◽  
Vol 2116 (1) ◽  
pp. 012121
Author(s):  
Mohammad Azarifar ◽  
Ceren Cengiz ◽  
Mehmet Arik
Keyword(s):  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Thermal Characterization ◽  
Thermal Control ◽  
Light Extraction Efficiency ◽  
Thickness Effect ◽  
Package Design ◽  
Light Emitting

Abstract Optical and thermal control are two main factors in package design process of lighting products, specifically light emitting diodes (LEDs). This research is aimed to study the role of secondary optics in opto-thermal characterization of LED packages. Novel thin total internal reflection (TIR) multifaceted reflector (MR) lens is modelled and optimized in Monte-Carlo ray-tracing simulations for MR16 package, regarded as one of the widely used LED lighting products. With criteria of designing an optical lens with 50% reduced thickness in comparison to commercially available lenses utilized in MR16 packages, nearly same light extraction efficiency and more uniform beam angles are achieved. Optical performance of the new lens is compared with the experimental results of the MR16 lamp with conventional lens. Only 2.3% reduction in maximum light intensity is obtained while lens size reduction was more than 25%. Based on the detailed CAD design, heat transfer simulations are performed comparing the lens thickness effect on heat dissipation of MR16 lamp. It was observed that using thinner lenses can reduce the lens and chip temperature, which can result in improved light quality and lifetime of both lens and light source.

Growth and Characterization of 1D Bi2Te3 Nanowires

2005 ◽  
Vol 886 ◽  
Author(s):  
M. Craps ◽  
Nick Gothard ◽  
Rahul Rao ◽  
Jian He ◽  
JoAn Hudson ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Room Temperature ◽  
Iron Catalyst ◽  
Inert Atmosphere ◽  
Laser Vaporization ◽  
Theoretical Studies ◽  
Low Dimensional ◽  
Quartz Substrates ◽  
Low Dimensional Materials

ABSTRACTBulk bismuth telluride (Bi2Te3) is one of the best known thermoelectric materials with a figure of merit ZT ∼1 at room temperature. Theoretical studies have suggested that low-dimensional materials may exhibit ZT values that exceed 1. In this study, we used the pulsed laser vaporization (PLV) method to prepare Bi2Te3 nanowires on silicon and quartz substrates by ablating Bi2Te3 targets in an inert atmosphere. Nano-sized gold or iron catalyst particles were used to seed the growth of the Bi2Te3 nanowires. Results from electron microscopy and Raman spectroscopy are discussed.

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