Topic
Thermal radiation
About: Thermal radiation is a research topic. Over the lifetime, 12290 publications have been published within this topic receiving 197186 citations. The topic is also known as: heat radiation.
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TL;DR: The characterization of temperature and thermal properties is of particular importance in micro- and nanotechnology and fundamental questions of the thermal behavior, for example, thermal transfer at a scale comparable to the phonon wavelength, could be more effectively addressed with improved characterization tools.
Abstract: The characterization of temperature and thermal properties is of particular importance in micro- and nanotechnology. Considering the highly increased density of structures and the increased power dissipation per unit area associated with miniaturization, good thermal design is of great importance for device reliability and performance. Locating hot spots, for example, on a microelectronic circuit, can be of great value in evaluating a design, optimizing the performance, and performing failure analysis. [1,2] Apart from the industrial applications of micro- and nanoscale thermometry, fundamental questions of the thermal behavior, for example, thermal transfer at a scale comparable to the phonon wavelength, [3] could be more effectively addressed with improved characterization tools. The common approach for mapping temperature on the microscale is based on infrared microscopy, which relies on the analysis of the thermal radiation that is emitted from any material. IR microscopy is a well-established technique and can be used with relative ease for temperature mapping on large scales. However, the technique suffers from a diffractionlimited resolution, giving it an optimal spatial resolution of around 5 mm. [2,4,5] Nanoscale scientists typically use scanning thermal microscopy (SThM) for high-resolution measurements. Since the invention of the scanning probe microscope at the beginning of the 1980s, [6] several scanning probes for thermal characterization have been developed. The thermal probes used are generally based on either thermocouple or thermistor elements. [7–11] Other approaches have proposed bimaterial cantilevers or fluorescent particles as temperaturesensing probes. [12–14] The highest spatial resolution obtained
165 citations
TL;DR: In this article, a two-epoch, multifrequency complete modeling of the broad band emission from the radio frequencies up to the very high gamma ray regime as observed during the April 1997 outburst is presented.
Abstract: We present two-epoch, multifrequency complete modeling of Mrk 501 broad band emission from the radio frequencies up to the very high gamma ray regime as observed during April 1997 outburst. To reproduce the X-ray and the gamma-ray radiation we assume an homogeneous Synchrotron-Self-Compton (SSC) model and approximate the electrons energy distribution by a broken power-law function with a sharp cut-o at high energy. We assume also spherical geometry of the emitting region (a blob) and uniform magnetic eld. For this scenario we derive constrains on physical parameters obtained from the observable quantities and can reproduce very well the observed Very High Energy (VHE) spectra. We nd that the two dierent high energy states cannot be explained by varying the particle energy distribution only. To obtain good spectral ts we have to change additionally one of the global parameters which describe the emitting blob: the magnetic eld intensity (B), the radius (Rb )o r the Doppler factor (b). We use a model of an inhomogeneous conical jet to explain radiation from the low radio frequencies up to the ultraviolet. A part of the physical parameters of this jet can be constrained from our ts of the high energy emission. The remaining parameters are estimated independently from other observations. We assume that the blob is placed somewhere inside the jet, relatively close to the central engine. Within this \blob- in-jet" scenario we analyze the eect of External Inverse-Compton (EIC) scattering of low energy synchrotron photons from the jet and thermal radiation surrounding the central engine. We show that EIC scattering can also very well explain VHE emission of Mrk 501 when external radiation is dominated by photons from the jet itself, which is an interesting alternative of the \blob-in-jet" scenario. Additional inverse-Compton scattering of relatively weak thermal external radiation cannot explain alone the spectra but can signicantly modify them, especially in the sub-TeV range, in comparison to spectral shape generated only with SSC model. We also analyze the absorption eect due to pair-production inside the source, which appears almost negligible. The same eect in the Intergalactic Infrared Background (IIB) may introduce signicant changes to the observed VHE spectra. In the infrared and optical parts of the spectrum, the contribution of the host galaxy is well reproduced by an elliptical galaxy evolution model. Three miniflares of Mrk 501 occurred in ten days between 7 and 16 April 1997 at the X-ray and gamma-ray frequencies. They can be well reproduced by simple variation of the break in the electron energy distribution function on time scale of a few hours, superposed to variation of the blob radius and of the particle density on time scale of about two days.
164 citations
TL;DR: In this article, a quantitative evaluation of dilepton sources in heavy-ion reactions is performed taking into account both thermal and non-thermal production mechanisms, and a convolution of the emission rates over a thermal fireball expansion results in good agreement with experiment in the low-mass spectra, confirming the predicted broadening of the ρ meson in hadronic matter in connection with the prevalence of baryon induced medium effects.
163 citations
TL;DR: It is shown that the thermal bistability could find broad applications in the domains of thermal management, information processing, and energy storage and can be used to store heat and thermal information for arbitrary long times.
Abstract: We predict the existence of a thermal bistability in many-body systems out of thermal equilibrium which exchange heat by thermal radiation using insulator-metal transition materials. We propose a writing-reading procedure and demonstrate the possibility to exploit the thermal bistability to make a volatile thermal memory. We show that this thermal memory can be used to store heat and thermal information (via an encoding temperature) for arbitrary long times. The radiative thermal bistability could find broad applications in the domains of thermal management, information processing, and energy storage.
162 citations
TL;DR: In this article, the effects of thermal radiation using the nonlinear Rosseland approximation are investigated and a numerical analysis in connection with the boundary layer flow induced in a quiescent fluid by a continuous sheet stretching with velocity uw (x) ∼x 1/3 with heat transfer is performed.
161 citations