Journal articles: 'Radiative thermal diodes'

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Tan, Yixuan, Baoan Liu, Sheng Shen, and Zongfu Yu. "Enhancing radiative energy transfer through thermal extraction." Nanophotonics 5, no. 1 (June 1, 2016): 22–30. http://dx.doi.org/10.1515/nanoph-2016-0008.

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Abstract Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics.Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal extraction. It is organized as follows. In Section 1, we will discuss the theory of thermal extraction [8]. In Section 2, we review an experimental implementation based on natural materials as the thermal extractor [8]. Lastly, in Section 3, we review the experiment that uses structured metamaterials as thermal extractors to enhance optical density of states and far-field emission [9].

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Kasali, Suraju Olawale, Jose Ordonez-Miranda, and Karl Joulain. "Optimization of the rectification factor of radiative thermal diodes based on two phase-change materials." International Journal of Heat and Mass Transfer 154 (June 2020): 119739. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2020.119739.

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Lin, Yuan-Chih, Marco Bettinelli, Suchinder K. Sharma, Britta Redlich, Adolfo Speghini, and Maths Karlsson. "Unraveling the impact of different thermal quenching routes on the luminescence efficiency of the Y3Al5O12:Ce3+ phosphor for white light emitting diodes." Journal of Materials Chemistry C 8, no. 40 (2020): 14015–27. http://dx.doi.org/10.1039/d0tc03821k.

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Shen, Dongyang, Chengzhao Luo, Ronghong Zheng, Qinyi Li, and Yu Chen. "Improvement of photoluminescence intensity and film morphology of perovskite by Ionic liquids additive." E3S Web of Conferences 257 (2021): 03066. http://dx.doi.org/10.1051/e3sconf/202125703066.

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Metal halide perovskites have received much attention for their application in light-emitting diodes (LEDs) and solar cells in the past several years. Among them, 2D and quasi-2D perovskite with organic long-chain cations introduced have drawn significant attention. However, while improving wet and thermal stability, as the grain size becomes smaller, more defects introduced at the grain boundary and surface, resulting in the increase of non-radiative recombination is becoming the main problem which should be faced by 2D/quasi-2D perovskite materials. Here, we report a new strategy employing ionic liquid named 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMB).By adding a small amount of ionic liquid to the precursor, the defect was effectively passivated and the photoluminescence intensity was increased by 11 times and the fluorescent lifetime was increased by about 1.5 times. The flatness of the prepared perovskite thin films has also been effectively improved.

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Patel, Ruchita R., G. K. Solanki, N. N. Gosai, and Rahul B. Patel. "DVT Grown GeSe Single Crystals and their Thermal Parameters in N₂." Advanced Materials Research 665 (February 2013): 8–14. http://dx.doi.org/10.4028/www.scientific.net/amr.665.8.

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Most of the applications of semiconductors involve either photon absorption to form free carriers (photodetectors or solar cells) or the formation of photons by free carrier recombination (light emittiing diodes or lasers). Both kinds of applications require high quality single crystals having desirable dimensions, devoid of defects, grain boundaries, or impurities that act as electron scatterers, traps and non radiative recombination centers. As a consequence of the requirement of high quality, fabrication and growth conditions for the semiconductors must be carefully controlled for most applications. Hence single crystals of GeSe were grown by Direct Vapor Transport (DVT) technique, in a two zone horizontal furnace with temperature difference of 50 K between growth and source zones. The material crystallizes in the form of shining gray and platelets like crystals at the end of growth cycles. Thermogravimetric analysis (TGA) has been used for many years to evaluate thermal stability of material as it will determine the range of stable operation for a device made up out of these materials under investigation. Thermal characteristics of GeSe crystals were studied employing thermoanalytical techniques, viz. TGA and DTA. Thermal analysis experiments were carried out with constant heating rate of 10 °C/ min in N2. The objective of this study is to determine activation energy and other kinetic parameters of GeSe crystals. Broido and Coats-Redfern (C-R) methods are used to evaluate different kinetic parameters of GeSe crystals viz. activation energy, entropy, enthalpy, Gibbs mean free energy etc.

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Zhou, Zhiguang, Enas Sakr, Yubo Sun, and Peter Bermel. "Solar thermophotovoltaics: reshaping the solar spectrum." Nanophotonics 5, no. 1 (June 1, 2016): 1–21. http://dx.doi.org/10.1515/nanoph-2016-0011.

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Abstract Recently, there has been increasing interest in utilizing solar thermophotovoltaics (STPV) to convert sunlight into electricity, given their potential to exceed the Shockley-Queisser limit. Encouragingly, there have also been several recent demonstrations of improved system-level efficiency as high as 6.2%. In this work, we review prior work in the field, with particular emphasis on the role of several key principles in their experimental operation, performance, and reliability. In particular, for the problem of designing selective solar absorbers, we consider the trade-off between solar absorption and thermal losses, particularly radiative and convective mechanisms. For the selective thermal emitters, we consider the tradeoff between emission at critical wavelengths and parasitic losses. Then for the thermophotovoltaic (TPV) diodes, we consider the trade-off between increasing the potential short-circuit current, and maintaining a reasonable opencircuit voltage. This treatment parallels the historic development of the field, but also connects early insights with recent developments in adjacent fields.With these various components connecting in multiple ways, a system-level end-to-end modeling approach is necessary for a comprehensive understanding and appropriate improvement of STPV systems. This approach will ultimately allow researchers to design STPV systems capable of exceeding recently demonstrated efficiency values.

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Sheikhi, Moheb, Yijun Dai, Mei Cui, Liang Li, Jianzhe Liu, Wenan Lan, Rongrong Jiang, Wei Guo, Kuan W. A. Chee, and Jichun Ye. "On the Luminescence Properties and Surface Passivation Mechanism of III- and N-Polar Nanopillar Ultraviolet Multiple-Quantum-Well Light Emitting Diodes." Micromachines 11, no. 6 (June 5, 2020): 572. http://dx.doi.org/10.3390/mi11060572.

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The non-centrosymmetricity of III-nitride wurtzite crystals enables metal or nitrogen polarity with dramatically different surface energies and optical properties. In this work, III-polar and N-polar nanostructured ultraviolet multiple quantum wells (UV-MQWs) were fabricated by nanosphere lithography and reactive ion etching. The influence of KOH etching and rapid thermal annealing treatments on the luminescence behaviors were carefully investigated, showing a maximum enhancement factor of 2.4 in emission intensity for III-polar nanopillars, but no significant improvement for N-polar nanopillars. The discrepancy in optical behaviors between III- and N-polar nanopillar MQWs stems from carrier localization in III-polar surface, as indium compositional inhomogeneity is discovered by cathodoluminescence mapping, and a defect-insensitive emission property is observed. Therefore, non-radiative recombination centers such as threading dislocations or point defects are unlikely to influence the optical property even after post-fabrication surface treatment. This work lays solid foundation for future study on the effects of surface treatment on III- and N-polar nanostructured light-emitting-diodes and provides a promising route for the design of nanostructure photonic devices.

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Huang, Yaren, Benedikt Lechner, and Gerhard Wachutka. "Comparative Numerical Analysis of the Robustness of Si and SiC PiN Diodes Against Cosmic Radiation-Induced Failure." Materials Science Forum 1004 (July 2020): 1088–96. http://dx.doi.org/10.4028/www.scientific.net/msf.1004.1088.

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This work aims at extending the predictive simulation technique for cosmic ray-induced failure analysis from Si PiN diodes [1] to SiC PiN diodes. Accurate 3D cylindrical-symmetric transient simulations were performed with a minimum mesh size of 20nm at the center track of the impinging ion and a maximum time step of 0.1ps during the development of the ion-induced transient current. We made a comparative study between a SiC PiN diode and a Si PiN diode with the same blocking voltage of 1.5kV, using the same heavy ion transportation models. In the simulation, we observed different ion-induced current transients, differing not only in the peak value of the current, but also in its duration. Due to different physical mechanisms, the dependence of the ion-induced current on the reverse pre-bias voltage and the numerical mesh adaptations are also different. Eventually, we brieflydiscuss electro-thermal simulations, which indicate once more that the ion-induced transient current in the SiC PiN diodes under consideration is primarily drift current and involves only negligible impact ionization.

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Karimov, A. V., A. Z. Rakhmatov, O. A. Abdulkhaev, U. H. Aripova, A. Yu Khidirnazarova, and Sh M. Kuliyev. "Controlling voltage drops in silicon diodes by electron irradiation and thermal treatment." Технология и конструирование в электронной аппаратуре, no. 4 (2018): 33–37. http://dx.doi.org/10.15222/tkea2018.4.33.

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High-frequency limiting rectifier diodes are used in power sources for rectifying alternating current, in protective elements of radio-electronic equipment, and in switching devices. They are the basis of energy-saving devices, meeting the high requirements for power limit and performance. The main task in the manufacturing process of high-frequency diodes is to ensure the low leakage current and the optimum value of the forward voltage drop which can be compared with the contact potential difference of the p–n junction. This paper is devoted to studying the effect of radiation exposure and subsequent heat treatment on the current-voltage and capacitance characteristics of high-frequency silicon diodes. The authors studied p+–p–n–n+ diodes made of n-type KEF-4 (ÊÝÔ-4) silicon wafers with an initial thickness of 235 µm. Radiation processing was performed using an ELU-6 (ÝËÓ-6) linear electron accelerator. The integral flux of “fast” electrons ranged from 1,0∙1015 to 2,6∙1017 cm–2, energy was 1.5 MeV, density was 1,7∙1011 — 5,5∙1013 cm–2∙s –1. Heat treatment was performed for 5 hours at a temperature of 90°C in a special chamber. The studies have shown that heat treatment lead to a shift of the forward current-voltage characteristic to a region of lower voltages (i.e., a given current can be reached at a lower voltage); at low current values, however, the voltage drop may increase after heat treatment. Reverse current decreased fivefold, resulting in a decrease in power output. At the same time, the temporal characteristics of the diode could also be improved by reducing the capacitance (to one order of magnitude)

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Kaur, C., S. Chaurasia, A. A. Pisal, A. K. Rossall, D. S. Munda, A. Venkateswara Rao, and M. N. Deo. "X-ray and ion emission studies from subnanosecond laser-irradiated SiO2 aerogel foam targets." Laser and Particle Beams 35, no. 3 (August 10, 2017): 505–12. http://dx.doi.org/10.1017/s0263034617000489.

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AbstractIn this experiment, a comparative study of ion and X-ray emission from both a SiO2 aerogel foam and a quartz target is performed. The experiment is performed using Nd:glass laser system operated at laser energy up to 15 J with a pulse duration of 500 ps with focusable intensity of 1013–1014 W/cm2 on target. X-ray fluxes in different spectral ranges (soft and hard) are measured by using X-ray diodes covered with Al filters of thickness 5 µm (0.9–1.56 keV) and 20 µm (3.4–16 keV). A 2.5 times enhancement in soft X-ray flux (0.9–1.56 keV) and a decrease of 1.8 times in hard X rays (3.4–16 keV) for 50 mg/cc SiO2 aerogel foam is observed compared with the solid quartz. A decrease in the flux of the K-shell line emission spectrum of soft X rays is noticed in the case of the foam targets. The high-resolution K-shell spectra (He-like) of Si ions in both the cases are analyzed for the determination of plasma parameters by comparing with FLYCHK simulations. The estimated plasma temperature and density are Tc = 180 eV, ne = 7 × 1020 cm−3 and Tc = 190 eV, ne = 4 × 1020 cm−3 for quartz and SiO2 aerogel foam, respectively. To measure the evolution of the plasma moving away from the targets, four identical ion collectors are placed at different angles (22.5, 30, 45, and 67.5°) from target normal. The angular distribution of the thermal ions are scaled as cosnθ with respect to target normal, where n = 3.8 and 4.8 for the foam and quartz, respectively. The experimental plasma volume measured from the ion collectors and shadowgraphy images are verified by a two-dimensional Eulerian radiative–hydrodynamic simulation (POLLUX code).

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Ben-Abdallah, Philippe, and Svend-Age Biehs. "Phase-change radiative thermal diode." Applied Physics Letters 103, no. 19 (November 4, 2013): 191907. http://dx.doi.org/10.1063/1.4829618.

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N.A., Sultanov, Raximov E.T., Mirzajonov Z., and Axmadjonov M.F. "Study Of The Influence Of Radiation Gamma And Thermal Annealing On The Dlts Spectra Of Diodes From Si (Cr)." American Journal of Applied Sciences 02, no. 10 (October 30, 2020): 33–36. http://dx.doi.org/10.37547/tajas/volume02issue10-06.

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It was shown from capacitive measurements that the concentration of chromium levels decreases after irradiation of the samples with gamma quanta of the 60Co isotope, and the rate of formation of A centres in Si (Cr) is 8-10 times higher than in the control samples.

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Karushkin, M. F. "Frequency multipliers on semiconductor diode structures." Технология и конструирование в электронной аппаратуре, no. 3 (2018): 22–37. http://dx.doi.org/10.15222/tkea2018.3.22.

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Obvious advantages of the millimeter wave technology including a large information capacity, high directivity of radiation, diagnostics and spectroscopy capabilities of different environments, including the methods of electron paramagnetic resonance and high resolution nuclear magnetic resonance have led to the rapid development of techniques for that range throughout the world. These advantages determine the attractiveness of the practical application of millimeter wavelengths to create high-speed communication links, high-precision radar, chemicals identification device and other equipment. Important role in the development of millimeter and sub-millimeter wave ranges belongs to the frequency multipliers development. This paper analyzes the main trends of modern development of efficient frequency multipliers on semiconductor diode structures, which are based on different physical principles, namely diode harmonic generators; frequency multipliers based on nonlinear dependencies of their reactive parameters on the voltage; frequency multipliers of high multiplicity on IMPATT diodes operating in mode of pulse exciting oscillations at high frequencies; multipliers on complex heterostructures and quantum super lattices in the terahertz range. The paper presents design solutions for frequency multipliers with various configurations and ways of optimizing the diode structures and operation modes that ensure their effective functioning in the frequency multiplication mode. The connection of electric parameters of frequency multipliers with output characteristics of microwave devices is determined. The given review of the results on designing power sources based on multiplying diodes indicates significant advances in this field and rapid development of the electronic component base in the short-wave part of the microwave spectrum. Further development of the technique of multiplying diodes will move forward not only in the direction of increasing the working capacity, but also in solving the problem of microminiaturization. In this regard, the emergence of heteroepitaxial multilayer varactor structures should be noted. Such structures are made with molecular beam epitaxy and have all the advantages of a composite varactor, but at the same time have better thermal characteristics and good prospects for their applications in the terahertz range.

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Uleckas, Aurimas, Eugenijus Gaubas, Joan Marc Rafi, Jiahe Chen, De Ren Yang, Hidenori Ohyama, Eddy Simoen, and Jan Vanhellemont. "Carrier Lifetime Studies in Diode Structures on Si Substrates with and without Ge Doping." Solid State Phenomena 178-179 (August 2011): 347–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.178-179.347.

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Results are presented of a comparative study of diodes processed on n-type Cz grown Si substrates without and with Ge doping concentration of about 1019 cm-3 and 1020 cm-3. In order to investigate thermal donor formation, isothermal annealing at 450°C for 0.5 – 5 h was carried out. As processed diodes were also irradiated with 2 MeV electrons with fluences in the range between 1014 and 1017 e/cm2 to investigate the Ge doping influence on irradiation induced defect formation. Diodes after thermal and radiation treatments have been investigated by combining different techniques.

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Pfeifer, Kent B., Komandoor E. Achyuthan, Matthew Allen, Michele L. B. Denton, Michael P. Siegal, and Ronald P. Manginell. "Microfabrication of a gadolinium-derived solid-state sensor for thermal neutrons." Journal of Radiation Research 58, no. 4 (March 25, 2017): 464–73. http://dx.doi.org/10.1093/jrr/rrx010.

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Abstract Neutron sensing is critical in civilian and military applications. Conventional neutron sensors are limited by size, weight, cost, portability and helium supply. Here the microfabrication of gadolinium (Gd) conversion material–based heterojunction diodes for detecting thermal neutrons using electrical signals produced by internal conversion electrons (ICEs) is described. Films with negligible stress were produced at the tensile-compressive crossover point, enabling Gd coatings of any desired thickness by controlling the radiofrequency sputtering power and using the zero-point near p(Ar) of 50 mTorr at 100 W. Post-deposition Gd oxidation–induced spallation was eliminated by growing a residual stress-free 50 nm neodymium-doped aluminum cap layer atop Gd. The resultant coatings were stable for at least 6 years, demonstrating excellent stability and product shelf-life. Depositing Gd directly on the diode surface eliminated the air gap, leading to a 200-fold increase in electron capture efficiency and facilitating monolithic microfabrication. The conversion electron spectrum was dominated by ICEs with energies of 72, 132 and 174 keV. Results are reported for neutron reflection and moderation by polyethylene for enhanced sensitivity, and γ- and X-ray elimination for improved specificity. The optimal Gd thickness was 10.4 μm for a 300 μm-thick partially depleted diode of 300 mm2 active surface area. Fast detection (within 10 min) at a neutron source-to-diode distance of 11.7 cm was achieved with this configuration. All ICE energies along with γ-ray and Kα,β X-rays were modeled to emphasize correlations between experiment and theory. Semi-conductor thermal neutron detectors offer advantages for field-sensing of radioactive neutron sources.

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Górecki, Krzysztof, and Przemysław Ptak. "Thermal, Photometric and Radiometric Properties of Multi-Color LEDs Situated on the Common PCB." Electronics 9, no. 10 (October 13, 2020): 1672. http://dx.doi.org/10.3390/electronics9101672.

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This paper presents the results of experimental investigations illustrating the influence of the spectra of the light emitted by power LEDs on their thermal, photometric and radiometric parameters. The investigations were performed for six diodes emitting white or monochromatic light of different spectra. Each of these diodes was produced by the same manufacturer, mounted in the same package and the tested devices were soldered to the common PCB. In the paper, the manner and set-ups making possible measurements of self and transfer transient thermal impedances, illuminance and the surface power density of the light emitted by the tested devices are described. Selected results of measurements are shown and discussed. These results prove that the spectra of the emitted light influence self-transient thermal impedances of the considered devices and transfer transient thermal impedances between some pairs of these devices. Additionally, it is proved that thermal couplings between the tested diodes strongly influence their junction temperature and the surface power density of the emitted radiation.

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Fiorino, Anthony, Dakotah Thompson, Linxiao Zhu, Rohith Mittapally, Svend-Age Biehs, Odile Bezencenet, Nadia El-Bondry, et al. "A Thermal Diode Based on Nanoscale Thermal Radiation." ACS Nano 12, no. 6 (May 23, 2018): 5774–79. http://dx.doi.org/10.1021/acsnano.8b01645.

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Ivashko, A. M., V. E. Kisel, and N. V. Kuleshov. "POWER SCALING IN CONTINUOUS-WAVE YB:YAG MICROCHIP LASER FOR MEASURING APPLICATIONS." Devices and Methods of Measurements 8, no. 3 (September 27, 2017): 222–27. http://dx.doi.org/10.21122/2220-9506-2017-8-3-222-227.

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Characteristics optimization of lasers used in different measuring systems is of great interest up to now. Diode-pumped microchip lasers is one of the most perspective ways for development of solid-state light sources with minimal size and weight together with low energy power consumption. Increasing of output power with good beam quality is rather difficult task for such type of lasers due to thermal effects in the gain crystal under high pump power.The investigation results of continuous-wave longitudinally diode-pumped Yb:YAG microchip laser are presented. In the presented laser radiation from multiple pump laser diodes were focused into the separate zone in one gain crystal that provides simultaneous generation of multiple laser beams. The energy and spatial laser beam characteristics were investigated.Influence of neighboring pumped regions on energy and spatial laser beams parameters both for separate and for sum laser output was observed. The dependences of laser output power from distance between neighboring pumped regions and their number were determined. Decreasing of laser output power was demonstrated with corresponding distance shortening between pumped regions and increasing their quantity with simultaneous improvement of laser beam quality.Demonstrated mutual influence of neighboring pumped regions in the longitudinally diode pumped Yb:YAG microchip laser allow as to generate diffraction limited Gaussian beam with 2W of continuous-wave output power that 30 % higher than in case of one pumped zone.

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Ott, Annika, Riccardo Messina, Philippe Ben-Abdallah, and Svend-Age Biehs. "Radiative thermal diode driven by nonreciprocal surface waves." Applied Physics Letters 114, no. 16 (April 22, 2019): 163105. http://dx.doi.org/10.1063/1.5093626.

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Davids, Paul S., Jared Kirsch, Andrew Starbuck, Robert Jarecki, Joshua Shank, and David Peters. "Electrical power generation from moderate-temperature radiative thermal sources." Science 367, no. 6484 (February 20, 2020): 1341–45. http://dx.doi.org/10.1126/science.aba2089.

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Moderate-temperature thermal sources (100° to 400°C) that radiate waste heat are often the by-product of mechanical work, chemical or nuclear reactions, or information processing. We demonstrate conversion of thermal radiation into electrical power using a bipolar grating-coupled complementary metal-oxide-silicon (CMOS) tunnel diode. A two-step photon-assisted tunneling charge pumping mechanism results in separation of charge carriers in pn-junction wells leading to a large open-circuit voltage developed across a load. Electrical power generation from a broadband blackbody thermal source has been experimentally demonstrated with converted power densities of 27 to 61 microwatts per square centimeter for thermal sources between 250° and 400°C. Scalable, efficient conversion of radiated waste heat into electrical power can be used to reduce energy consumption or to power electronics and sensors.

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Trivellin, Nicola, Matteo Meneghini, Matteo Buffolo, Gaudenzio Meneghesso, and Enrico Zanoni. "Analysis and Reliability Study of Luminescent Materials for White Lighting." Proceedings 2, no. 17 (May 15, 2018): 1158. http://dx.doi.org/10.3390/ecms2018-05233.

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In this work, we report on the characterization and reliability/stability study of phosphorescent materials for lighting applications. More specifically, we investigated (a) phosphors directly deposited over light-emitting diodes (LED) chip, (b) remote phosphor (RP) solutions encapsulated in plastic medium for LED lighting, and (c) phosphors without binder for extreme high-intensity laser diode white lighting. The optical and thermal properties of phosphors were studied to develop a sample based on a mix of phosphor compounds in order to achieve different correlated color temperatures (CCT) and high color rendering index (CRI) LEDs. Thermal properties of cerium-doped YAG (Yttrium Aluminum Garnet) phosphor materials were evaluated in order to study thermal quenching. A maximum phosphor operating temperature of 190–200 °C was found to cause a sensible efficiency degeneration. Reduced efficiency and Stokes shift also caused a localized temperature increase in the photoluminescent materials. In the case of remote phosphors, heat did not find a low thermal resistance path to the heatsink (as occurred through the GaN LED chip for direct phosphor-converted devices) and thermal analysis indicated that material temperature might therefore increase to values in excess of 60 °C when a radiation of 435 mW/cm2 hit the sample template. Reliability was also investigated for both plastic-encapsulated materials and binder-free depositions. Pure thermal reliability study indicated that phosphors encapsulated in polycarbonate material were stable up to temperature of approximately 100 °C, while binder-free phosphor did not show any sensible degradation up to temperatures of 525 °C.

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Radulović, Vladimir, Klemen Ambrožič, Ivana Capan, Robert Bernat, Zoran Ereš, Željko Pastuović, Adam Sarbutt, et al. "SILICON CARBIDE NEUTRON DETECTOR PROTOTYPE TESTING AT THE JSI TRIGA REACTOR FOR ENHANCED BORDER AND PORTS SECURITY." EPJ Web of Conferences 247 (2021): 16002. http://dx.doi.org/10.1051/epjconf/202124716002.

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In 2016, the “E-SiCure” project (standing for “Engineering Silicon Carbide for Border and Port Security”), funded by the NATO Science for Peace and Security Programme was launched. The main objective is to combine theoretical, experimental and applied research towards the development of radiation-hard SiC-based detectors of special nuclear materials (SNM), with the end goal to enhance border and port security barriers. Prototype neutron detectors, configured as 4H-SiC-based Schottky barrier diodes, were developed for the detection of secondary charged particles (tritons, alphas and lithium atoms) which are the result of thermal neutron reactions on 10B and 6LiF layers above the surface of the 4H-SiC diodes. We designed a stand-alone prototype detection system, consisting of a preamplifier, shaping amplifier and a multichannel analyser operated by a laptop computer, for testing of neutron detector prototypes at the Jožef Stefan Institute (JSI) TRIGA reactor using a broad beam of reactor neutrons. The reverse bias for the detector diode and the power to electronic system were provided by a standalone battery-powered voltage source. The detector functionality was established through measurements using an 241Am alpha particle source. Two dedicated experimental campaigns were performed at the JSI TRIGA reactor. The registered pulse height spectra from the detectors, using both 10B and 6LiF neutron converting layers, clearly demonstrated the neutron detection abilities of the SiC detector prototypes. The computed neutron detection sensitivity of the single prototype detectors demonstrates that scaling SiC detectors into larger arrays, of dimensions relevant for border and port radiation detectors, could enable neutron sensitivity levels matching gas-based detector technology.

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Dumitrescu, Anca Laura, Marius Paulescu, and Aurel Ercuta. "A Solid State Pyranometer." Annals of West University of Timisoara - Physics 58, no. 1 (December 1, 2015): 56–63. http://dx.doi.org/10.1515/awutp-2015-0207.

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Abstract The construction of a solid state device-based pyranometer designated to broadband irradiance measurements is presented in this paper. The device is built on the physical basis that the temperature difference between two bodies of identical shape and external surface area, identically exposed to the incident radiation, but having different absorption and heat transfer coefficients (e.g. one body is painted white and the other is painted black), is proportional to the incident irradiance. This proportionality may be put in evidence if the two bodies consisting of identical arrays of correspondingly painted semiconductor diodes, due to the thermal behaviour of their p-n junction. It is theoretically predicted and experimentally confirmed that the voltage drop across a diode passed through a constant forward current linearly decreases with the temperature of the junction. In other words, a signal proportional to the irradiance of the light source may be obtained via conventional analog electronics. The calibration of the apparatus, as performed by means of a professional device (LP PYRA 03), indicates a good linearity.

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Bliznyuk, V. V., V. A. Parshin, N. S. Savinov, A. A. Selivanov, and A. E. Tarasov. "Features of measurements the IR radiation power of a laser diode used in active optoelectronic systems for studying flows." Journal of Physics: Conference Series 2127, no. 1 (November 1, 2021): 012047. http://dx.doi.org/10.1088/1742-6596/2127/1/012047.

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Abstract In active optical-electronic systems for stream research that regulate thermal-physical parameters of diagnosed stream volume, the controlled source of the heat flow can be acquired by radiation of high-power IR laser diodes into the void. In the current work the peculiarities of measurement of this radiation are considered, specified by its strong divergence. It is shown that the measurements can involve laser wattmeters IMO-4M with planar thermoelectric primary measuring transformers of the laser radiation with a flat receiving site provided.

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Lv, Ling, Peixian Li, Xiaohua Ma, Linyue Liu, Ling Yang, Xiaowei Zhou, Jincheng Zhang, et al. "Fast and Thermal Neutron Radiation Effects on GaN PIN Diodes." IEEE Transactions on Nuclear Science 64, no. 1 (January 2017): 643–47. http://dx.doi.org/10.1109/tns.2016.2630061.

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Radulović, Vladimir, Klemen Ambrožič, Luka Snoj, Ivana Capan, Tomislav Brodar, Zoran Ereš, Željko Pastuović, et al. "E-SiCure Collaboration Project: Silicon Carbide Material Studies and Detector Prototype Testing at the JSI TRIGA Reactor." EPJ Web of Conferences 225 (2020): 07007. http://dx.doi.org/10.1051/epjconf/202022507007.

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In 2016, the ”E-SiCure” project (standing for Engineering Silicon Carbide for Border and Port Security), funded by the NATO Science for Peace and Security Programme, was launched. The main objective is to combine theoretical, experimental and applied research towards the development of radiation-hard SiC-based detectors of special nuclear materials (SNM), and by that way, to enhance border and port security barriers. Along the plan, material modification processes are employed firstly to study, and secondly to manipulate the most severe electrically active defects (which trap or annihilate free charge carriers), by specific ion implantation and defect engineering. This paper gives an overview of the experimental activities performed at the JSI TRIGA reactor in the framework of the E-SiCure project. Initial activities were aimed at obtaining information on the radiation hardness of SiC and at the study of the energy levels of the defects induced by neutron irradiation. Several Schottky barrier diodes were fabricated out of nitrogen-doped epitaxial grown 4H-SiC, and irradiated under Cd filters in the PT irradiation channel in the JSI TRIGA reactor with varying neutron fluence levels. Neutron-induced defects in the material were studied using temperature dependent current-voltage (I-V), capacitance-voltage (C-V) and Deep-Level Transient Spectroscopy (DLTS) measurements. Our prototype neutron detectors are configured as 4H-SiC-based Schottky barrier diodes for detection of secondary charged particles (tritons, alphas and lithium atoms) which are result of thermal neutron conversion process in 10B and 6LiF layers above the surface of the 4H-SiC diodes. For field testing of neutron detectors using a broad beam of reactor neutrons we designed a standalone prototype detection system consisting of a preamplifier, shaping amplifier and a multichannel analyser operated by a laptop computer. The reverse bias for the detector diode and the power to electronic system are provided by a standalone battery-powered voltage source. The detector functionality was established through measurements using an 241Am alpha particle source. Two dedicated experimental campaigns were performed at the JSI TRIGA reactor. The registered pulse height spectra from the detectors, using both 10B and 6LiF neutron converting layers, clearly demonstrated the neutron detection abilities of the SiC detector prototypes.

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Makarenko, L. F., F. P. Korshunov, S. B. Lastovski, Stanislav B. Lastovskii, N. M. Kazuchits, M. S. Rusetsky, Eckhart Fretwurst, et al. "Effect of Hydrogenation on Defect Reactions in Silicon Particle Detectors." Solid State Phenomena 108-109 (December 2005): 217–22. http://dx.doi.org/10.4028/www.scientific.net/ssp.108-109.217.

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The influence of preliminary treatment in hydrogen plasma on elimination of radiation defects and formation of thermal donors has been studied in detector structures made of standard and oxygenated float zone silicon has been studied. A new type of thermal donors has been found in as-treated diodes. These thermal donors are unstable and can be eliminated by heat-treatment at 200-250°C. After irradiation with 3.5 MeV electrons the detectors had been annealed at temperatures of 50-350 °C. It has been found that preliminary hydrogenation at 300 °C leads to disappearance of main vacancy-type radiation defects at lower annealing temperatures. The annealing of hydrogenated and irradiated crystals is accompanied by hydrogen redistribution and formation of hydrogen-related donors. Preliminary irradiation influences on both these processes.

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Mironovich, Lyudmila M., Pavel V. Afanas'yev, and Anna Yu Podol’nikova. "SYNTHESIS OF 3-TERT-BUTYL-9-R-PYRIMIDO[4,5:3,4]PYRAZOLO[5,1-C][1,2,4]TRIAZINE-4(6H),11(10H)- DIONES AT CONDITIONS OF MICROWAVE RADIATION." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 59, no. 3 (July 12, 2018): 74. http://dx.doi.org/10.6060/tcct.20165903.5252.

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3-tert-butyl-9-R-pyrimido[4’,5’:3,4]pyrazolo[5,1-c][1,2,4]triazine-4(6H),11(10H)-diones was synthesized at the conditions of microwave radiation. The reaction kinetic characteristics were obtained under conditions of thermal and microwave heating.

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Ganiyev, Sabuhi, M. Azim Khairi, D. Ahmad Fauzi, Yusof Abdullah, and N. F. Hasbullah. "The effects of electron irradiation and thermal dependence measurements on 4H-Sic Schottky diode." Физика и техника полупроводников 51, no. 12 (2017): 1721. http://dx.doi.org/10.21883/ftp.2017.12.45193.8646.

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In this paper the effects of high energy (3.0 MeV) electrons irradiation over a dose ranges from 6 to 15 MGy at elevated temperatures 298 to 448 K on the current-voltage characteristics of 4H-SiC Schottky diodes were investigated. The experiment results show that after irradiation with 3.0 MeV forward bias current of the tested diodes decreased, while reverse bias current increased. The degradation of ideality factor, n, saturation current, Is, and barrier height, Phib, were not noticeable after the irradiation. However, the series resistance, Rs, has increased significantly with increasing radiation dose. In addition, temperature dependence current-voltage measurements, were conducted for temperature in the range of 298 to 448 K. The Schottky barrier height, saturation current, and series resistance, are found to be temperature dependent, while ideality factor remained constant. DOI: 10.21883/FTP.2017.12.45193.8646

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Afanas’ev, A. V., V. A. Il’in, I. G. Kazarin, and A. A. Petrov. "Thermal stability and radiation hardness of SiC-based schottky-barrier diodes." Technical Physics 46, no. 5 (May 2001): 584–86. http://dx.doi.org/10.1134/1.1372950.

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Chen, Yenlung, Juikun Chang, Chun Huang, Changche Chiu, Wei Lai, Zhiting Ye, and Pin Han. "Development of Radiator with Thermoplastic Polymer and Insert-Molded Aluminum Alloy Parts for Light-Emitting Diode Headlights." Applied Sciences 12, no. 11 (May 26, 2022): 5385. http://dx.doi.org/10.3390/app12115385.

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The increasing popularity of electric vehicles has increased the demand for lightweight auto parts. However, the excessive weight of traditional metal heat sinks has remained a concern. Metal has excellent thermal conductivity but low radiation efficiency. Conversely, thermoplastic polymers have excellent heat radiation efficiency but poor thermal conductivity. In this study, we propose a radiator constructed using thermoplastic polymer and insert-molded aluminum alloy parts to maintain the low junction temperature of light-emitting diodes (LEDs); the radiator’s weight is reduced through a combination of aluminum alloy and a thermally conductive polymer designed for automotive headlights. At an LED thermal load of 11.48 W, the measured temperature on the LED pad is 60.8 °C. The weight of the proposed radiator is 23.37% lighter than that of a pure metal radiator. When the lightweight radiator is used in high-power LED headlights, it effectively dissipates heat within a limited space.

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Фомин, А. В., С. Р. Усманов, А. Н. Игнатьев, and Е. В. Кадигроб. "Лазерный модуль с волоконным выводом излучения яркостью более 10 MW/(cm-=SUP=-2-=/SUP=-·sr)." Журнал технической физики 92, no. 4 (2022): 616. http://dx.doi.org/10.21883/jtf.2022.04.52250.305-21.

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The work was dedicated to the laser modules for the spectral range of 975 nm based on single laser diodes with fiber output to be designed and manufactured. The installation of an optical system for the seven laser diodes radiation input into a silica-silica fiber with a core diameter of 105 μm and a numerical aperture of 0.15 has been carried out while investigating their power and spectral characteristics. The maximum output power of the laser module was 65 W in CW operation at a nominal current of 12 A and a thermal stabilization temperature of 25 ° C, the total efficiency of the laser module was 43%, and the brightness of the laser module amounted to 10.6 MW / cm2•sr.

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Zhao, Weixian, Zhan Zhu, Yiwen Fan, Wang Xi, Run Hu, and Xiaobing Luo. "Temporally-adjustable radiative thermal diode based on metal-insulator phase change." International Journal of Heat and Mass Transfer 185 (April 2022): 122443. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2021.122443.

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34

YANG Lian-qiao, 杨连乔, 付美娟 FU Mei-juan, 魏斌 WEI Bin, 张建华 ZHANG Jian-hua, and 曹进 CAO Jin. "Thermal Analysis and Thermal Design of Organic Light-emitting Diode." Chinese Journal of Luminescence 33, no. 6 (2012): 624–27. http://dx.doi.org/10.3788/fgxb20123306.0624.

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35

Lisiecki, Aleksander. "Study of Optical Properties of Surface Layers Produced by Laser Surface Melting and Laser Surface Nitriding of Titanium Alloy." Materials 12, no. 19 (September 24, 2019): 3112. http://dx.doi.org/10.3390/ma12193112.

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This study measured optical properties, such as specular, diffuse, and total reflection for 808 nm wavelength, characteristic for high power diode lasers radiation, from the surface of titanium alloy Ti6Al4V at delivery conditions, polished, and oxidized. Moreover, the optical properties of surface layers produced by high power direct diode laser (HPDDL) melting and nitriding were determined. Additionally, a methodology for determining the value of absorption for 808 nm wavelength of the HPDDL radiation on the surface of a melt pool during laser surface melting and nitriding of titanium alloy was proposed. The results show that the distinct differences in absorption affect the heat transfer, thermal conditions of laser heating and thereby the penetration depth during laser melting and nitriding of the titanium alloy.

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36

Ahmad Fauzi, Dhiyauddin, Nahrul Khair Alang Md Rashid, Muhammad Rawi Mohamed Zin, and Nurul Fadzlin Hasbullah. "RADIATION PERFORMANCE OF GAN AND INAS/GAAS QUANTUM DOT BASED DEVICES SUBJECTED TO NEUTRON RADIATION." IIUM Engineering Journal 18, no. 1 (May 30, 2017): 101–9. http://dx.doi.org/10.31436/iiumej.v18i1.653.

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In addition to their useful optoelectronics functions, gallium nitride (GaN) and quantum dots (QDs) based structures are also known for their radiation hardness properties. With demands on such semiconductor material structures, it is important to investigate the differences in reliability and radiation hardness properties of these two devices. For this purpose, three sets of GaN light-emitting diode (LED) and InAs/GaAs dot-in-a well (DWELL) samples were irradiated with thermal neutron of fluence ranging from 3Ã—1013 to 6Ã—1014 neutron/cm2 in PUSPATI TRIGA research reactor. The radiation performances for each device were evaluated based on the current-voltage (I-V) and capacitance-voltage (C-V) electrical characterisation method. Results suggested that the GaN based sample is less susceptible to electrical changes due to the thermal neutron radiation effects compared to the QD based sample.

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37

Szyszka, Jerzy, Piero Bevilacqua, and Roberto Bruno. "An Innovative Trombe Wall for Winter Use: The Thermo-Diode Trombe Wall." Energies 13, no. 9 (May 1, 2020): 2188. http://dx.doi.org/10.3390/en13092188.

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The use of passive solutions for building envelopes represents an important step toward the achievement of more efficient and zero-energy building targets. Trombe walls are an interesting and viable option for the reduction of building energy requirements for heating, especially in cold climates. This study presents the experimental analysis of an innovative Trombe wall configuration, named a thermo-diode Trombe wall, which was specifically designed to improve the energy efficiency by providing a proper level of insulation for the building envelope. Such a design is essential in cold climates to limit the thermal losses whilst increasing solar heat gains to the heated spaces. An experimental campaign was conducted from December to March that involved monitoring the external climatic conditions and the main thermal parameters to assess the thermal performance of the proposed solution. The results demonstrated that in the presence of solar radiation, the thermo-diode Trombe wall was able to generate significant natural convection inside the air cavity, with temperatures higher than 35 °C in the upper section, by providing consistent heat gains for the indoor environment, even on cold days and for hours after the end of the daylight. The efficiency, relative to the incident solar radiation, reached 15.3% during a well-insolated winter day.

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38

Esa, Mazlina, Mohd Khairul Hisham Ismail, Noor Asniza Murad, Nik Noordini Nik Abd. Malik, Mohd Fairus Mohd Yusoff, and Shipun Anuar Hamzah. "Effect of Electrical Field Resonances due to Perturbation Slit Tunnel Junction for a Potential Solar Energy Collector at 10 Micrometer Radiation." Applied Mechanics and Materials 781 (August 2015): 458–61. http://dx.doi.org/10.4028/www.scientific.net/amm.781.458.

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A potential solar energy collector is proposed. The design is a new rectangular antenna with perturbation slit tunnel junction that exhibits highly confined electrical-field at 10 micrometer radiation. The configuration operates at the centre resonant for thermal radiation spectrum. The vital idea behind this proposed design is to trap and guide out the electrical-field using slit tunnel into a convenient location for potential solar energy collector. The trapping electrical field achieved is enhanced up to 110 V/m with an excitation plane wave of 1 V/m. Meanwhile, a wider half-field strength bandwidth up to 13.5 THz is successfully excited to cover most of the thermal radiation spectrum. By the introduction of a tunnel junction of 0.1 micrometer for diode integration, the electrical field magnitude slightly decreased to 98.3 V/m with half-field strength bandwidth of 12 THz. Furthermore, the promising results generated by finite integration technique (FIT) method offers the proposed design to be a potential candidate for energy harvesting devices at 10 micrometer thermal radiation of the sun.

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Brown, E. R., A. C. Young, J. E. Bjarnason, J. D. Zimmerman, A. C. Gossard, and H. Kazemi. "MILLIMETER AND SUB-MILLIMETER WAVE PERFORMANCE OF AN ERAS:INALGAAS SCHOTTKY DIODE COUPLED TO A SINGLE-TURN SQUARE SPIRAL." International Journal of High Speed Electronics and Systems 17, no. 02 (June 2007): 383–94. http://dx.doi.org/10.1142/s0129156407004576.

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We report the first experimental results for noise-equivalent power (NEP) and noise-equivalent temperature difference (NETD) of single-crystal ErAs:InAlGaAs , zero-bias rectifier diodes coupled to free space quasi-optically in the THz region. At a frequency of 639 GHz, an optical NEP of 4.0×10−12 W / Hz 1/2 is measured with the rectifier coupled to a quasi-plane-wave coherent source through a single-turn square spiral antenna. With a broadband thermal (hot water) source, an NETD of 120 mK is measured from the same device. Antenna radiation patterns at 100 GHz and 639 GHz are also presented.

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40

Vernydub, R. M., O. I. Kyrylenko, O. V. Konoreva, D. P. Stratilat, V. P. Tartachnyk, M. M. Filonenko, and V. V. Shlapatska. "Spectral characteristics of initial and irradiated GaAsP LEDs." Nuclear Physics and Atomic Energy 22, no. 2 (June 25, 2021): 143–48. http://dx.doi.org/10.15407/jnpae2021.02.143.

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The optical characteristics of the GaAs1-хPх output LEDs and LEDs irradiated with electrons with Е = 2 MeV, Ф = 1015 ÷ 1016 cm-2 were studied. The width of the band gap of the GaAs1-хPх (х = 0.45) solid solution was estimated. Its growth is caused by the heating of carriers by the field of the p-n junction. The damage coefficients of the lifetime of minority charge carriers for irradiated GaAsP LEDs have been calculated and the consequences of exposure to radiation on the operational parameter Т1, which determines the thermal stability of the diodes, have been analyzed.

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41

Brown, Christopher S., Andrew C. Schuerger, and John C. Sager. "Growth and Photomorphogenesis of Pepper Plants under Red Light-emitting Diodes with Supplemental Blue or Far-red Lighting." Journal of the American Society for Horticultural Science 120, no. 5 (September 1995): 808–13. http://dx.doi.org/10.21273/jashs.120.5.808.

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Light-emitting diodes (LEDs) are a potential irradiation source for intensive plant culture systems and photobiological research. They have small size, low mass, a long functional life, and narrow spectral output. In this study, we measured the growth and dry matter partitioning of `Hungarian Wax' pepper (Capsicum annum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation or under broad spectrum metal halide (MH) lamps. Additionally, we describe the thermal and spectra1 characteristics of these sources. The LEDs used in this study had a narrow bandwidth at half peak height (25 nm) and a focused maximum spectral output at 660 nm for the red and 735 nm for the far-red. Near infrared radiation (800 to 3000 nm) was below detection and thermal infrared radiation (3000 to 50,000 nm) was lower in the LEDs compared to the MH source. Although the red to far-red ratio varied considerably, the calculated phytochrome photostationary state (φ) was only slightly different between the radiation sources. Plant biomass was reduced when peppers were grown under red LEDs in the absence of blue wavelengths compared to plants grown under supplemental blue fluorescent lamps or MH lamps. The addition of far-red radiation resulted in taller plants with greater stem mass than red LEDs alone. There were fewer leaves under red or red plus far-red radiation than with lamps producing blue wavelengths. These results indicate that red LEDs may be suitable, in proper combination with other wavelengths of light, for the culture of plants in tightly controlled environments such as space-based plant culture systems.

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CHEN Huan-ting, 陈焕庭, 陈福昌 CHEN Fu-chang, 何. 洋. HE Yang, 林. 硕. LIN Shuo, 熊传兵 XIONG Chuan-bing, 周锦荣 ZHOU Jin-rong, and 陈赐海 CHEN Ci-hai. "Analysis of Thermal Characteristics of A Multichip Light-emitting Diodes Device." Chinese Journal of Luminescence 39, no. 5 (2018): 751–56. http://dx.doi.org/10.3788/fgxb20183905.0751.

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Taylor, Neil R., Yongchao Yu, Mihee Ji, Tolga Aytug, Shannon Mahurin, Richard Mayes, Sacit Cetiner, et al. "Thermal and radiation response of 4H–SiC Schottky diodes with direct-write electrical contacts." Applied Physics Letters 116, no. 25 (June 22, 2020): 252108. http://dx.doi.org/10.1063/5.0007496.

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Kuptsov, Gleb, Alexei Laptev, Vladimir Petrov, Victor Petrov, and Efim Pestryakov. "THE INVESTIGATION OF THERMAL LENS PROPERTIES IN THE ACTIVE ELEMENT OF LASER AMPLIFIER WITH HIGH POWER DIODE PUMP." Interexpo GEO-Siberia 8 (2019): 3–9. http://dx.doi.org/10.33764/2618-981x-2019-8-3-9.

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A femtosecond laser system with a pulse repetition rate up to 1 kHz is being developed at the Institute of Laser Physics of the SB RAS. The key component of the system is the channel of laser amplification based on media doped with Yb3+ ions. The designed average output power of the channel is 300 W. Thermal effects in high-power laser amplifiers are decisive for the parameters of the radiation at the output of system. In this paper the results of experimental measurements of thermal lens focal distance dependence in Yb:YAG active element on diode pump power using geometric method are given. Calculation of the dependence thermal lens focal distance on the power of pump power and a comparison with experimental data are given.

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Lin, Ah-Der, Sian Zheng Poon, Hong-Wei Tu, Cheng-Yi Chen, and Chao-Ming Hsu. "Study on Thermoelectric Conversion and Conjugate Heat Transfer for PCBA by Finite Element Analysis." Applied Sciences 10, no. 1 (December 25, 2019): 197. http://dx.doi.org/10.3390/app10010197.

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In this study, the optical sphere and the power analyzer were exploited to measure the optical and power parameters for the high-power LED lamps. The results, derived from the experimental data, were used as the power distribution inputs in the finite element analysis (FEA) for the determination of the temperature distribution for the printed circuit board assembly (PCBA) built in the LED lamp. In the finite element analysis, the conjugate heat transfer model was adapted for the calculation of the heat transfer, including thermal conductivity, convection and radiation. Applied on the power chips located on the PCBA, the graphene thermal interface material (TIMs) had been studied for its effects on the temperature distribution. For an accurate simulation about the LED lamp, the model with closed and compact space was built in the analysis. Compared to the experimental data, it showed that the simulation results had a deviation in the range of 3–5% around the main heating source, the light-emitting diodes. It proves the FEA model proposed in this study were well developed for the simulation of the temperature distribution for the high-power LED lamps which have mixed heat transfer mechanisms. The thermal radiation effects by TIMs with graphene were also investigated in this study and proven to be useful for the heat dissipation for the LED lamps.

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Barsukov, D. P., A. A. Matevosyan, I. K. Morozov, A. N. Popov, and M. V. Vorontsov. "The influence of small-scale magnetic field on the heating of J0250+5854 polar cap." Journal of Physics: Conference Series 2103, no. 1 (November 1, 2021): 012034. http://dx.doi.org/10.1088/1742-6596/2103/1/012034.

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Abstract The influence of surface small-scale magnetic field on the heating of PSR J0250+5854 polar cap is considered. It is assumed that the polar cap is heated only by reverse positrons accelerated in pulsar diode. It is supposed that pulsar diode is located near the star surface (polar cap model) and operates in the steady state space charge-limited flow regime. The reverse positron current is calculated in the framework of two models: rapid and gradually screening. To calculate the production rate of electron-positron pairs we take into account only the curvature radiation of primary electrons and its absorption in magnetic field. It is assumed that some fraction of electron-positron pairs may be created in bound state that can later be photoionized by thermal photons from star surface.

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Et.al, DalievKhojiakbarSultanovich. "Increasing the Thermostability of Optoelectronic Devices on Semiconductor Radiators." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 3 (April 10, 2021): 3112–19. http://dx.doi.org/10.17762/turcomat.v12i3.1535.

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The article proposes a scheme for thermal stabilization of the radiation flux of mid-IR LEDs in the temperature range + 20 ° C + 80 ° C. It is shown that the relevance of mid-IR LEDs for solving problems of gas analysis, environmental monitoring, moisture measurement and medical diagnostics. It was revealed that the guarantee of the measurement accuracy and sensitivity of optoelectronic devices is the correct spectral matching of the photodetector, LED and absorption of the investigated substance. The disadvantages of emitting diodes associated with time and temperature instability during operation are considered. A study of the spectral characteristics of mid-IR LEDs at various temperatures showed that the wavelength at the maximum the emission spectrum increases almost linearly with increasing temperature, which leads to additional errors and lowers the measurement accuracy of optoelectronic devices. A schematic diagram is proposed for stabilizing the radiation flux of mid-IR LEDs in the temperature range + 20 ° C + 80 ° C..

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Ohyama, H., K. Takakura, T. Nagano, M. Hanada, S. Kuboyama, Eddy Simoen, and Cor Claeys. "Degradation and their Recovery Behavior of Irradiated GaAlAs LEDs." Solid State Phenomena 131-133 (October 2007): 119–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.131-133.119.

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The degradation and recovery behavior of device performance on GaAlAs LEDs (Light emitting diodes) irradiated by 2-MeV electrons and 70-MeV protons are investigated. The reverse current increases after irradiation, while the capacitance decreases. The device performance degradation is proportional with fluence. For electron irradiation, fluence rate is also effective for degradation. Low fluence rate shows more large degradation compared to high fluence rate resulting from heat impact in bulk. DLTS measurement reveals the DX center in epitaxial substrate, and this spectrum increases with fluence. The radiation damage of proton is larger than that of electron irradiation, which is caused by the difference of mass and possibility of nuclear collision for the formation of lattice defects. After irradiation, the device performance recovers by thermal annealing.

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Kim, Hansol, Ah Hyun Jung, Sung Hee Park, Yohan Yoon, and Beob Gyun Kim. "In Vitro Protein Disappearance of Raw Chicken as Dog Foods Decreased by Thermal Processing, but Was Unaffected by Non-Thermal Processing." Animals 11, no. 5 (April 27, 2021): 1256. http://dx.doi.org/10.3390/ani11051256.

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The objectives of the present study were to determine the influence of thermal and non-thermal processing procedures on in vitro ileal disappearance (IVID) of dry matter (DM) and crude protein (CP) in chicken meat as dog foods using 2-step in vitro assays. In thermal processing experiments, IVID of DM and CP in chicken meat thermally processed at 70, 90, and 121 °C, respectively, with increasing processing time was determined. For non-thermal processing experiments, IVID of DM and CP in chicken meat processed by high-pressure, ultraviolet-light emitting diode (UV-LED), electron-beam, and gamma-ray was determined. Thermal processing of chicken meat at 70, 90, and 121 °C resulted in decreased IVID of CP (p < 0.05) as heating time increased. In non-thermal processing experiment, IVID of CP in chicken meat was not affected by high-pressure processing or UV-LED radiation. In vitro ileal disappearance of CP in electron-beam- or gamma-ray-irradiated chicken meat was not affected by the irradiation intensity. Taken together, ileal protein digestibility of chicken meat for dogs is decreased by thermal processing, but is minimally affected by non-thermal processing methods.

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Liu, Yang, Yanpei Tian, Fangqi Chen, Andrew Caratenuto, Xiaojie Liu, Mauro Antezza, and Yi Zheng. "Ultrahigh-rectification near-field radiative thermal diode using infrared-transparent film backsided phase-transition metasurface." Applied Physics Letters 119, no. 12 (September 20, 2021): 123101. http://dx.doi.org/10.1063/5.0058779.

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Journal articles on the topic 'Radiative thermal diodes'

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