| 1. |
- Ning, Yuping, et al.
(författare)
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Effects of substrates, film thickness and temperature on thermal emittance of Mo/substrate deposited by magnetron sputtering
- 2016
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Ingår i: Vacuum. - : Elsevier BV. - 0042-207X .- 1879-2715. ; 128, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- The thermal emittance of the Mo film, as an IR-refiector in solar selective absorbing coatings, is the most important property. The effects of the substrate material, the substrate surface roughness, the film thickness and the temperature on the thermal emittance of the Mo/substrate have been investigated. A series of Mo films with increasing film thickness were deposited on two types of substrate materials (glass and stainless steel). A saturated Mo thickness of 50 nm is found to produce the lowest thermal emittance. The thermal emittance of the Mo film is reduced by decreasing the substrate surface roughness. The emittance of the optimal Mo film remains 0.05 from 25 degrees C to 400 degrees C, which can meet the optical requirements for the IR-reflector.
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| 2. |
- Ning, Yuping, et al.
(författare)
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Investigation on low thermal emittance of Al films deposited by magnetron sputtering
- 2016
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Ingår i: Infrared physics & technology. - : Elsevier BV. - 1350-4495 .- 1879-0275. ; 75, s. 133-138
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Tidskriftsartikel (refereegranskat)abstract
- A series of Al films with different thicknesses were deposited on polished stainless steel by direct current (DC) magnetron sputtering as a metal IR-reflector layer in solar selective absorbing coating (SSAC). The effects of the film thickness and the temperature on the thermal emittance of the Al films are studied. An optimal thickness 78 nm of the Al film for the lowest total thermal emittance is obtained. The thermal emittance of the optimal Al film keeps close to 0.02 from 25 degrees C to 400 degrees C, which are low enough to satisfy the optical requirements in SSAC. The optical constants of the AI film are deduced by fitting the reflectance and transmission spectra using SCOUT software.
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| 3. |
- Ning, Yuping, et al.
(författare)
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Optical simulation and preparation of novel Mo/ZrSiN/ZrSiON/SiO2 solar selective absorbing coating
- 2017
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 167, s. 178-183
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Tidskriftsartikel (refereegranskat)abstract
- A novel Mo/ZrSiN/ZrSiON/SiO2 solar selective absorbing coating has been investigated, which was prepared by magnetron sputtering on stainless steel substrate. A high solar absorptance of 0.94 and a low thermal emittance of 0.06 at 25 degrees C were achieved. By proportionally decreasing the thicknesses of the ZrSiN, ZrSiON and SiO2 layers, the thermal emittance at 500 degrees C was decreased significantly from 0.19 to 0.12 (Delta epsilon = 0.07) while keeping the solar absorptance unchanged. The coating also showed high thermal stability at 500 degrees C in vacuum, implying that it is a promising candidate for high temperature concentrated solar power (CSP) applications.
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| 4. |
- Ning, Yuping, et al.
(författare)
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Tuning of reflectance transition position of Al-AlN cermet solar selective absorbing coating by simulating
- 2017
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Ingår i: Infrared physics & technology. - : Elsevier BV. - 1350-4495 .- 1879-0275. ; 80, s. 65-70
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Tidskriftsartikel (refereegranskat)abstract
- The reflectance spectra of the AI/double cermet Al-AIN/AIO(x)N(y) solar selective absorbing coating are simulated. Two methods have been found to effectively tune the position of reflectance transition of the Al-MN cermet solar selective absorbing coating, which is crucial to obtain a low emittance at elevated temperature. The position of reflectance transition is mainly determined by the high metal volume fraction (HMVF) cermet layer. It is effectively tuned to shift to lower wavelength by reducing the metal volume fraction or the thickness of the HMVF layer. This provides easy ways to tune the position of reflectance transition.
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| 5. |
- Sai, Hanna, et al.
(författare)
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Observations of the very young Type Ia Supernova 2019np with early-excess emission
- 2022
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 514:3, s. 3541-3558
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Tidskriftsartikel (refereegranskat)abstract
- Early-time radiative signals from Type Ia supernovae (SNe Ia) can provide important constraints on the explosion mechanism and the progenitor system. We present observations and analysis of SN 2019np, a nearby SN Ia discovered within 1–2 days after the explosion. Follow-up observations were conducted in optical, ultraviolet, and near-infrared bands, covering the phases from ∼−16.7 d to ∼+ 367.8 d relative to its B-band peak luminosity. The photometric and spectral evolutions of SN 2019np resemble the average behaviour of normal SNe Ia. The absolute B-band peak magnitude and the post-peak decline rate are Mmax(B) = −19.52 ± 0.47 mag and Δm15(B) = 1.04 ± 0.04 mag, respectively. No Hydrogen line has been detected in the nebular-phase spectra of SN 2019np. Assuming that the 56Ni powering the light curve is centrally located, we find that the bolometric light curve of SN 2019np shows a flux excess up to 5.0 per cent in the early phase compared to the radiative diffusion model. Such an extra radiation perhaps suggests the presence of an additional energy source beyond the radioactive decay of central nickel. Comparing the observed colour evolution with that predicted by different models, such as interactions of SN ejecta with circumstellar matter (CSM)/companion star, a double-detonation explosion from a sub-Chandrasekhar mass white dwarf (WD) and surface 56Ni mixing, we propose that the nickel mixing is more favoured for SN 2019np.
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| 6. |
- Wu, Yongxin, et al.
(författare)
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Optical simulation and experimental optimization of Al/NbMoN/NbMoON/SiO2 solar selective absorbing coatings
- 2015
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 134, s. 373-380
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Tidskriftsartikel (refereegranskat)abstract
- For the applications in solar thermal power, the preparation and optimization of an Al/NbMoN/NbMoON/SiO2 multilayer solar selective absorbing coating are carried out by combining experiments with optical simulation. A series of NbMoN and NbMoON single layers are deposited by magnetron reactive sputtering method with different N-2/O-2 gas flowing rates. And then their optical constants are obtained by fitting their reflection (R) and transmission (T) spectra in the wavelength range of 300-2500 nm using SCOUT software. These optical constants are used to design the Al/NbMoN/NbMoON/SiO2 solar selective absorbing coating so as to get the ideal spectral selectivity, i.e. high alpha/epsilon ratio. According to the optical design of the coating structure, we prepared the all-layer coating, and the thickness of each layer was optimized until the best spectral selective properties are obtained. The experimental reflectance spectrum fits very well with the simulated result. The optimized solar absorbing coating deposited on stainless steel substrate exhibited high absorptance (alpha=0.948) and low emittance (epsilon=0.050) at 80 degrees C. It offers a good method to quickly reach the ideal spectral selectivity through optical simulation. The thermal stability of the coating is evaluated, and it exhibits a good thermal stability in vacuum at 400 degrees C.
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| 7. |
- Wu, Yongxin, et al.
(författare)
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Study on the thermal stability of Al/NbTiSiN/NbTiSiON/SiO2 solar selective absorbing coating
- 2015
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Ingår i: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 119, s. 18-28
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the NbTiSiN and NbTiSiON layers are used instead of NbTiN and NbTiON layers to further improve the thermal stability of Al/NbTiN/NbTiON/SiO2 multilayer solar selective absorbing coating. The thermal stability of Si-doped individual layers and multilayer coatings are investigated. The X-ray diffraction (XRD) results show that Si incorporation into NbTiN (NbTiSiN) layer does not change its preferred orientation, and the Si-doped NbTiON (NbTiSiON) layer remains in amorphous phase. On the other hand, by introducing Si into NbTiN and NbTiON layers induce significant improvement of the oxidation resistance at 500 degrees C in air. After ageing in air at 500 degrees C for 2 h, the absorptance and emittance (at 400 degrees C) of Al/NbTiN/NbTiON/SiO2 and Al/NbTiSiN/NbTiSiON/SiO2 multilayer coatings change from 0.934/0.13 and 0.931/0.12 to 0.538/0.14 and 0.922/0.13, respectively. Meanwhile the surface roughness increases from 18.3 and 7.9 to 41.5 and 14.7 respectively, as atomic force microscopy (AFM) shows. The Al/NbTiSiN/NbTiSiON/SiO2 coating still has a high absorptance (0.910) and low emittance (0.13, at 400 degrees C) after ageing at 550 degrees C in vacuum for 100 h. It displays that Si-doping play an important role in the improvement of the thermal stability.
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