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Radiative energy and exergy analyses of spectrally-selective surfaces for CSP systems
摘要： This work presents a new methodology for calculations of spectral radiative energy and radiative exergy to evaluate the performances of concentrated solar power (CSP) systems. Spectral radiative properties and the operating temperature of selective surfaces, along with the temperature of the environment, are taken into account in analyses. The fundamental expressions needed for the spectral radiative energy and exergy analyses are introduced first. Then, the two approaches are used to assess the spectral performance of five selective coatings. The spectral analysis is performed in the wavelength range of 250 nm to 20,000 nm, while thermal analysis is carried out for the temperature range of 325 K to 800 K. NREL 6A coating was found to result in the highest radiative energy and radiative exergy for both efficiencies and gains, and for the best thermal stability compared to the other coatings.
关键词： selective coating,spectral radiative energy analysis,concentrating solar power systems,spectral radiative exergy analysis
更新于2025-09-23 15:23:52
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Effects of Metal Dopings on CuCr <sub/>2</sub> O <sub/>4</sub> Pigment for Use in Concentrated Solar Power Solar Selective Coatings
摘要： The process of fabricating the solar absorbing spinel-structured CuCr2O4 black oxide pigment doped with different metals (Mn, Ni, Co, Al, Zn, and Sn) was discovered to improve the solar selective property. Manganese stands out as an ideal dopant to Copper Chromite (CuCr2O4) for highly solar absorptive pigments compared to the other metal dopings. XRD analysis confirmed that various molar ratio of CuCr(2-x)MnxO4 spinel black oxides were successfully fabricated. Mn-doped black oxide has the highest absorptivity (the lowest band gap value of 1.35 eV) among other metal doping black oxides produced by the hydrothermal synthesis. Manganese is the only dopant that suppresses reflectance peaks exhibited by the copper chromium oxide at 1 μm and 1.5 μm in the light spectrum, raising the solar absorptivity of the pigment. Different manganese doping compositions are introduced to CuCr(2-x)MnxO4 where x = 0.1, 0.25, 0.5, 1, 1.5, 1.75, and 1.9. The high selective solar absorptivity appears after 100% (x=1) manganese doping with solar absorbance 0.9874 and a Figure of Merit (FOM) value of 0.9284.
关键词： Concentrated Solar Power,Solar selective coating,Solar-absorbing pigment,Black paint,Spinel black oxide.
更新于2025-09-23 15:23:52
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Anti-reflection high-index metasurfaces combining Mie and Fabry-Pérot resonances
摘要： Minimizing reflection losses is required for the efficient operation of a wide range of optical components. Anti-reflection coatings supporting Fabry-Pérot resonances are commonly used to solve this problem and can be applied on an industrial scale. Recent work has shown that reflections can also be reduced by placing an array of high-index nanostructures on a surface. In such coatings, anti-reflection is achieved by tailoring the scattering by optical Mie resonances. Here, we design and fabricate Si metasurfaces that combine both Fabry-Pérot and Mie resonances in a single metasurface to realize a multi-resonant broadband anti-reflection response. We optically characterize the metasurfaces demonstrating 4.1% AM1.5–averaged reflectance across the visible spectrum (425–900 nm). Our metasurface design strategy is generally applicable to different materials and frequency ranges, making our approach relevant for a broad variety of applications.
关键词： Mie resonators,Metasurface,Effective Medium,Anti-Reflection Coating (ARC),Fabry-Pérot resonances
更新于2025-09-23 15:23:52
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Realization of effective laser blanking process by heat zone spread resistance coating and optimization methods
摘要： Laser blanking process is widely used for the ability to cut complex profiles on sheet metal without Die.Laser blanking process needs optimization methods to reduce wastage of raw material and cutting time. The work entails optimization of sheet metal nesting allocation to reduce wastage and also optimizes cutting time by reducing ideal travel distance. The laser irradiation induces heat affected zone in the cutting surface leading to poor service life of the components in the cutting edges. The development of AlN heat zone spread resistance coating over steel substrate through a reactive sputtering process is presented. The thin film preparation is carried out in two different combinations of Argon and Nitrogen ratio namely 1:1 and 2:1, respectively. The coating over the steel substrate is exposed to laser to analyze the micro-structural change induced by the laser in the cutting edges. The coating is observed to mitigate the spreading of heat zone. The coatings are further subjected to tafel polarization to analyze the corrosion resistance of the steel substrate.In this paper, an approach has been made to obtain an optimal allocation based on the selection of different dimensions of the AlN coated sheet and also to calculate the utilization and cutting time. The proposed method provides an optimal layout for parts using a software and to obtain minimum travel ideal distance a heuristic algorithm is used. Since the sheet is coated there is also an add-on advantage in minimizing cutting time. Finally, an Optimal Pareto front is developed between wastage and ideal cutting distance, in order to provide choices for the user to select the requirement in both cases.
关键词： Laser Blanking,Pareto Front,Coating,Optimization
更新于2025-09-23 15:23:52
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Influence of the precursor concentration on the morphological and structural properties of zinc oxide (ZnO)
摘要： Three precursor concentrations were used for synthesizing zinc oxide nanoparticules by sol-gel via spin-coating method. The final products were synthesized at calcination temperatures of 550 °C during 2 hours. X-ray diffraction (XRD) analysis showed that ZnO thin films were preferentially oriented along the (002) c-axis direction perpendicular to the substrate surface and had crystalline structure with a hexagonal wurtzite phase. EDX microanalysis and morphological investigations using SEM indicated respectively that the products consist of zinc (Zn) and oxygen (O) elements and the stoichiometric atomic ratio of Zn:O ? 1:1, and surface of nanoparticles is homogeneous. Comparing the XRD report of three samples, it has been concluded that samples prepared at 0.75M condition give high intensity of fine peaks and better improved properties with potential applications as transparent electrodes in optoelectronic devices such as solar cells. Therefore, this deposition condition can be used for further deposition condition for reproductivity in other research laboratories.
关键词： Spin-coating,properties,ZnO,influence of concentration
更新于2025-09-23 15:23:52
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[IEEE 2018 International Symposium on Electromagnetic Compatibility (EMC EUROPE) - Amsterdam (2018.8.27-2018.8.30)] 2018 International Symposium on Electromagnetic Compatibility (EMC EUROPE) - Terahertz Shielding Prediction of Id-Periodic N Anolayered Coatings by an Effective Homogeneous Model
摘要： An innovative effective-medium model of 1D-periodic multilayer coatings is developed by applying the transmission line method. Each period consisting of several layers with subwavelength thickness in the nanometer range is modelled as a homogeneous medium characterized by an effective complex conductivity and unit relative permeability. The resulting effective single layer (ESL), having the same total thickness of the multilayer laminate, is represented by a transfer matrix given by the product of the transmission matrices of the periods composing the structure. The effective homogeneous model is used to compute the shielding effectiveness of 1D-periodic photonic-band-gap transparent coatings made by alternating layers of silver and zinc oxide films in the frequency range up to 10 THz. The good accuracy of the results obtained using the ESL is demonstrated by comparison with the results computed by means of the rigorous multilayer formulation.
关键词： THz shielding effectiveness,1D-periodic multilayer coating,effective homogeneous model
更新于2025-09-23 15:23:52
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Synthesis and characterization of nickel free titanium–hydroxyapatite composite coating over Nitinol surface through in-situ laser cladding and alloying
摘要： In this study, a high power fibre laser was used to synthesize titanium hydroxyapatite composite coating over biomedical-grade Nitinol surface through laser in-situ formation, cladding and alloying processes. The laser fluence is varied in the range of 2 kJ/cm2 to 8 kJ/cm2 in view of establishing a relationship between various in-situ phase-formation characteristics along with the rate of diffusion of the base material in the cladding zone with molten pool temperature. The alloying with base Nitinol material and subsequent diffusion of titanium to the in-situ formed calcium phosphate cladding layer are observed in the samples treated with laser fluence of 4 kJ/cm2 or above. Double layer configuration of the solidified molten pool is mostly found in all the cladding samples. At the fluence of 6 kJ/cm2 or above, the top layer primarily comprises segregated titanium-hydroxyapatite phase along with diffusion of titanium from the base material. Whereas, the bottom part of the molten pool is dominated with titanium-rich nickel–titanium intermetallic reinforced with nano particles. The steady-state variations of calcium and elemental presence of titanium through the cladding cross-section along with no nickel or oxide presence are confirmed through EDS line scans. The spherical and lamellar structures of formation of titanium-hydroxyapatite on the top surface also help to improve the overall corrosion resistance properties as compared to the bare surface. The modulus of elasticity is controlled by the variation of the top layer and intermediate layer composition and thickness, which varies with laser fluence. It falls in the range of 6–30 GPa which is similar to natural bone. Thus this nickel-free alloying and cladding layer of titanium-hydroxyapatite can serve as one of the potential candidates for use as a coating over the load bearing Nitinol implants to arrest the nickel release phenomena.
关键词： Titanium–calcium coating,Biocompatible functional coating,Hydroxyapatite,Nitinol surface modification,Laser cladding and alloying
更新于2025-09-23 15:22:29
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Effectiveness of phased array focused ultrasound and active infrared thermography methods as a nondestructive testing of Ni-WC coating adhesion
摘要： The substrate/coating adhesion is a crucial parameter conditioning the quality of coating and its durability in service. For this reason, an inspection of the coating integrity, in particular, the presence of adhesion defects will be of great importance. The adhesion inspection is usually ensured by destructive methods, such as traction, interfacial indentation, four-point bending, testing scratch, etc. However, it is currently hampered by the absence of a satisfactory non-destructive method. Among the non-destructive testing technologies widely used in the industrial field, there are X-ray diffraction, ultrasonic inspection, and infrared thermography. In this paper, two methods are investigated: ultrasonic inspection, which becoming more efficient, especially with the emergence of phased array systems that allow to investigate different inspection angles and focusing depths, and the active infrared thermography. Experiments were performed on metallic coatings deposited on a mild steel substrate. Coatings were containing artificial defects (flat bottom holes with different diameters) at the interface and others were exempts of defects. Longitudinal waves with specific delay laws were generated through a phased array contact transducer (5 MHz of central frequency). Experimental results show that the ultrasonic method allows detecting and sizing defects with a diameter of 1 mm located in thick coatings.
关键词： Substrate/coating adhesion,phased array,defects,detection,nondestructive testing,coating
更新于2025-09-23 15:22:29
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - A novel organic coating assisted laser drilling method for TSV fabrication
摘要： Through-silicon vias (TSVs) is a promising three-dimensional packaging solution in post-Moore's law era in the semiconductor industry. The fabrication of through silicon via plays an important role in three-dimensional packaging. Laser drilling is widely used in TSVs fabrication. However, the geometry quality of laser drilling is unsatisfied and heat affected zone (HAZ) is intrinsic. In this work, a novel organic coating assisted picosecond UV laser drilling method is proposed to obtain high-quality TSVs, the HAZ was noticeably eliminated and the TSVs quality was significantly improved. The effects of the organic thickness and laser power on the TSVs' quality were also studied in detail. It is found that the diameter of vias decreases with the increase of the organic thickness and decrease of the laser power. The minimum diameter of TSV obtained by this method is about 15 μm while the aspect ratio is beyond 30. Most importantly, by coating with the organic layer, the minimized via diameter can be decreased to about only 70% of the laser spot size which breaks the limit that the minimized via should be larger than or at least equal to the laser spot size. These findings will be helpful for TSV technology development in modern three-dimensional packaging.
关键词： ultraviolet picosecond laser drilling,through silicon via,heat affected zone elimination,organics coating method
更新于2025-09-23 15:22:29
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AIP Conference Proceedings [Author(s) ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2016: Proceedings of the International Conference on Advanced Materials with Hierarchical Structure for New Technologies and Reliable Structures 2016 - Tomsk, Russia (19–23 September 2016)] - Protection from high-velocity impact particles for quartz glass by coatings on the basis of Al-Si-N
摘要： The paper presents the results of the research of the phase composition and the mechanical properties of the coatings on the basis of Al-Si-N system produced by pulsed magnetron sputtering on the KV glass substrates. By the X-ray diffraction method, it has been discovered that the coatings contain AlN phase (hcp) with different thickness. The deposition of Al-Si-N coating system allows both increasing the microhardness of the surface layer of the quartz glass up to 29 GPa, and maintaining high elastic properties (We > 0.70). The laboratory tests have been carried out involving the impact of high-speed flows of iron particles on the Al-Si-N protective coating with different thicknesses produced by pulsed magnetron sputtering. The increase of Al-Si-N coating thickness from 1μm to 10μm decreases 4-fold the surface density of the craters on the samples caused by a high-speed flow of iron particles.
关键词： structure-phase state,microhardness,crater density,optical properties,protective coating,magnetron deposition
更新于2025-09-23 15:22:29