Irradiated cubic single crystal SiC as a high temperature sensor
Radiation is known to cause point defects formation in different materials. In the case of cubic SiC single crystal radiation flux on the order of 2⋅10 20 neutrons/cm 2 at 0.18 MeV causes over 3% volume lattice expansion. Radiation-induced strain (measurable by X-Ray diffraction) can be relieved when the annealing temperature exceeds the temperature of irradiation. Based on this effect the original technology of maximum temperature measurement was developed a while ago. Single crystal SiC sensor small size (200-500 microns), wide temperature range (150-1450 °C), “no-lead” installation, and exceptional accuracy make it very attractive for use in small, rotating and “hard-to-access” parts, including, but not limited to gas turbine blades, space shuttle ceramic tiles, automobile engines, etc. With the advances in X-Ray diffraction measurements, crystal and thin film growth techniques, it is the time to revise and update this technology. Modeling radiation damage, as well as annealing effects are also beneficial.
One-dimensional nano layered SiC/TiO2 based photonic band gap materials as temperature sensor
Abstract In this present paper, we have proposed a novel design of temperature sensor using 1-dimensional photonic band gap materials, which is made by alternate layers of TiO2 and silicon carbide (4H–SiC) with periodic variation of their respective thickness and refractive indices. We have investigated the reflection properties, relative band width behaviour and group velocity of the proposed photonic band gap materials at different temperature. The refractive index of SiC is temperature dependent, so by increasing the temperature the number of forbidden bands as well as width of the forbidden bands increases and the value of group velocity decreases. Thus, by analysing the band gap width, number of forbidden bands, and group velocity, it is easy to calculate the value of temperature of the given environment. This paper is focused on what we regard the latest development in the use of photonic band gap materials in photonic devices, a strong importance with the application in communication. It may be used as a temperature sensor. Our results show the potential application in temperature controlled optoelectronic devices.
Effect of temperature on the solvated electron in 1-propanol
Abstract The technique of pulse radiolysis has been used to study the effect of temperature on the solvated electron in 1-propanol. The spectrum of the solvated electron has been measured in the range 140–298 K. The wavelength at maximum absorption, λ max , decreases with decreasing temperature (corresponding to an increase in the energy, E max ) but the spectral width at half height, ΔE 1 2 , changes little with temperature. At temperatures above ≈180 K, the formation of the solvated electron is complete at the end of the pulse and its spectrum shows no change in shape with time. Below ≈170 K, the absorption spectrum is time-dependent in both liquid and glassy phases, the changes being attributed to the solvation process. The reaction(s) leading to solvated electron formation following the pulse show an activation energy of 22±2 kJ mol − and the solvated electron decays with an activation energy of 20±2 kJ mol −1 . The yield of solvated electrons decreases continuously with decreasing temperature in the range 298-77 K and, at all temperatures studied, is less than the total ionization yield measured by scavenging techniques.