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Journal articles on the topic 'Secondary reflector'

Author: Grafiati

Published: 4 June 2025

Last updated: 14 July 2025

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Domingos, Gonçalo, José Carlos Garcia Pereira, Pedro Alexandre Rodrigues Rosa, José Rodríguez, and Luís Guerra Rosa. "Experimental Validation of Double Paraboloid Reflection for Obtaining Quasi-Homogeneous Distribution of Concentrated Solar Flux." Energies 16, no. 9 (2023): 3927. http://dx.doi.org/10.3390/en16093927.

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This work demonstrates that the quasi-homogeneous distribution of concentrated solar flux is achievable by using double paraboloid reflection, with a primary reflector to concentrate the sunlight, and a secondary reflector to homogenise the radiation flux. For that, three slightly different secondary reflectors were designed and manufactured, matching the specifications of the paraboloid concentrator of the SF60 solar furnace located in PSA—Plataforma Solar de Almería, which was used as primary reflector. Starting from preliminary simulations of the optical apparatus, the secondary geometries were selected and then the reflectors were manufactured from 7075-T6 aluminium alloy, using conventional and CNC machining technologies, with further processing to achieve a mirror-like finish. The results obtained from solar irradiation tests corroborate that the “double paraboloid reflection” methodology proposed in previous theoretical works seems to be technically feasible and can be a solution for obtaining homogeneously distributed fluxes of highly concentrated solar radiation.

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Ahmed Abd-Eltawab Altaher, Mohamed Salama Abd-Elhady, Mohamed Nagiub El-Sheikh, and Seif Alnasr Ahmed. "The Effect of Using Secondary Reflectors on the Thermal Performance of Solar Collectors with Evacuated Tubes." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 99, no. 2 (2022): 187–96. http://dx.doi.org/10.37934/arfmts.99.2.187196.

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The aim of this paper is to improve the thermal performance of the evacuated tube solar collectors by using secondary reflectors and covering the collector surface area with an aluminum foil. Adding a secondary reflecting surface in the form of a parabola fixed on the end of the parabolic trough, acts as an additional reflective surface, which increases the input energy to the solar collector and consequently improves the thermal output of the collector. Two solar collectors were manufactured, one with modifications and the other without modifications, which is taken as a reference for the sake of comparison. Four experiments were performed; the first and second experiments reported the influence of adding a horizontal and a vertical secondary reflector on the solar collector efficiency. In the third and fourth experiment the effect of covering the collector surface area with aluminum foil together with a secondary vertical reflector on the heat gained by the bulb is examined. It is found that the average temperature of the heat pipe bulb in case of a secondary reflector installed horizontally is about 2.5% greater than the average temperature of the reference collector, while in case of the secondary reflector installed vertically is 7% greater than the reference collector. Adding the secondary reflecting surface in the vertical position, and covering the surface area of main parabola and the secondary reflector with aluminum foil, has increased the temperature of the heat pipe bulb by 11%. Finally, adding a secondary vertical reflector to the parabolic trough collector and covering both reflectors, i.e. the primary and the secondary reflectors, with aluminum foil improve the heating capability of the solar collector.

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Chinnasamy, Subramaniyan, Subramani Jothirathinam, Kalidasan Balasubramanian, et al. "Investigation on the Optical Design and Performance of a Single-Axis-Tracking Solar Parabolic trough Collector with a Secondary Reflector." Sustainability 13, no. 17 (2021): 9918. http://dx.doi.org/10.3390/su13179918.

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The design of solar concentrating collectors for the effective utilization of solar energy is a challenging condition due to tracking errors leading to different divergences of the solar incidence angle. To enhance the optical performance of solar parabolic trough collectors (SPTC) under a diverged solar incidence angle, an additional compound parabolic concentrator (CPC) is introduced as a secondary reflector. SPTC with CPC is designed and modeled for a single axis-tracking concentrating collector based on the local ambient conditions. In this work, the optical performance of the novel SPTC system with and without a secondary reflector is investigated using MATLAB and TRACEPRO software simulations for various tracking errors. The significance parameters such as the solar incidence angle, aperture length, receiver tube diameter, rim angle, concentration ratio, solar radiation, and absorbed flux are analyzed. The simulation results show that the rate of the absorbed flux on the receiver tube is significantly improved by providing the secondary reflector, which enhances the optical efficiency of the collector. It is found that the optical efficiency of the SPTC with a secondary reflector is 20% higher than the conventional collector system for a solar incidence angle of 2°. This work can effectively direct the choice of optimal secondary reflectors for SPTC under different design and operating conditions.

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Feuermann, D., and J. M. Gordon. "Analysis of a Two-Stage Linear Fresnel Reflector Solar Concentrator." Journal of Solar Energy Engineering 113, no. 4 (1991): 272–79. http://dx.doi.org/10.1115/1.2929973.

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The two-stage linear Fresnel reflector solar concentrator is analyzed via an in-depth study of an installed, nominally 220 KWt system. The concentrator includes: (1) a primary linear Fresnel reflector comprised of curved mirrors and (2) a secondary nonimaging CPC-type trough with a tubular receiver. The principal practical design options for the secondary concentrator are evaluated. Via a computer simulation which includes ray-tracing of the primary reflector, we evaluate the sensitivity of energy output to: concentrator optical errors, system geometry, tracking mode, and the option of using flat versus curved primary mirrors. The two-stage Fresnel concentrator can be considerably less expensive than the corresponding parabolic trough collector, but is found to deliver about one-fourth less yearly energy. However, much of this difference could be eliminated through the use of higher-quality CPC reflectors.

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Veremachi, Amos, Boaventura Chongo Cuamba, Azher Zia, Jorgen Lovseth, and Ole Jorgen Nydal. "PCM Heat Storage Charged with a Double-Reflector Solar System." Journal of Solar Energy 2016 (August 2, 2016): 1–8. http://dx.doi.org/10.1155/2016/9075349.

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A “Solar Salt” (NaNO3–KNO3 60 : 40 molar mixture) latent heat storage has been charged by direct solar illumination. Solar Salt as a Phase Change Material (PCM) can be an attractive small scale heat storage solution, as the melting temperature of about 220°C can be suitable for cooking purposes. The tests were made with a double-reflector setup. In this setup a secondary reflector positioned above the focal point of the primary reflector directs the rays onto a heat storage positioned below a hole in the primary reflector. The reflectors are tracking the sun, but the storage is stationary. The direct illumination of the absorber top plate during the tracking of the sun melted the salt in the storage through conducting fins. This is a system where portable heat batteries can be charged, during sunshine hours, and then provide heat for cooking during evening times.

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Kumar, Arun, Santanu Dwari, Ganga Prasad Pandey, Binod Kumar Kanaujia, and Dinesh Kumar Singh. "A high gain wideband circularly polarized microstrip antenna." International Journal of Microwave and Wireless Technologies 12, no. 7 (2020): 678–87. http://dx.doi.org/10.1017/s1759078719001612.

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AbstractIn this paper, a high gain wideband circularly polarized (CP) microstrip antenna is presented for broadband operation. The proposed structure comprised of a partially grounded printed monopole antenna loaded with a split ring resonator and a metallic reflector. By using the metallic reflector surface underneath the patch radiator results in the reflected waves in the same phase with main lobe radiation, thereby improving the gain and it also acts like a secondary radiator to generate wideband CP behavior in the proposed design. A gain enhancement of 4.3 dBi is achieved in the operating frequency band as compared with the design without a metallic reflector. The maximum gain achieved in the presented method is 8.6 dBic over the entire operating range. The proposed design shows a wideband behavior ranging from 4.30 to 9.10 GHz with the 10-dB impedance bandwidth of 71.64%. In addition, the proposed design yielded a broadside right hand CP radiation with a 3-dB axial ratio bandwidth of 33.88% from 4.98 to 7.01 GHz. The proposed antenna is fabricated and experimental results on reflection coefficient, gain, axial ratio, and radiation patterns concede well with simulation results.

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Yershov, V. N. "A Giant Meridian Circle - Reflector." Symposium - International Astronomical Union 166 (1995): 360. http://dx.doi.org/10.1017/s007418090022843x.

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A 1.5 m reflector is proposed for infrared and optical meridian observations in order to extend the fundamental coordinate system to faintest objects and to the K-infrared waveband. Classical meridian circles are unfit for the infrared observations because their lens objectives do not give good images in the infrared. But reflectors are almost never used as meridian circles due to uncertainties in their optical axis position. The main problem is that the secondary mirror is not connected with the micrometer and the circle reading system. In order to overcome this difficulty the author proposes to use an intermediary focal plane between the primary and the secondary mirrors where a luminous reference grid of wires might be placed. The Gregory optical scheme has such a focal plane, and its secondary mirror forms images of a star and the grid at the micrometer's detecting area. At the same time a special champher around the primary's central hole forms anautocollimated image of the grid near the grid itself. The micrometer measures the star image coordinates relative to two images of the reference grid. So, observations will not be affected by displacements of the secondary mirror and by those of the micrometer. The telescope's equivalent focal length has been chosen as 3 m, and the optical system has been transformed into an aplanatic Mersenne combined with an aplanatic focal reducer corrector (Popov, 1988). A new autocollimated circle reading system is chosen for the instrument (Yershov and Nemiro, 1994). The observations will be linked to the fixed optical axis of two long-focus collimators placed at the prime vertical plane.

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WANG, ChengLong, Jun MA, and YangJun XIA. "Research progress on secondary concentrator for linear Fresnel reflector." SCIENTIA SINICA Technologica 50, no. 8 (2020): 997–1008. http://dx.doi.org/10.1360/sst-2020-0190.

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Zhang, Dongliang, Tong W. Fei, Constantine Tsingas, and Yi Luo. "Efficient wave-equation-based diffraction imaging." GEOPHYSICS 84, no. 5 (2019): S389—S399. http://dx.doi.org/10.1190/geo2018-0568.1.

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We have developed an efficient and practical wave-equation-based technique to image subsurface geologic features such as isolated scatterers, reflector edges, fault, fracture zones, and erosion whose information is mainly contained in diffracted waves. This technique has the ability to directly reveal and differentiate important geologic features compared with results obtained using reflected seismic waves. This new technique comprises three steps. First, the source and receiver wavefields are decomposed into left- and right-downgoing propagating waves, respectively. Second, applying the imaging condition to the right-downgoing source and receiver wavefields to generate the so-called right-right image. Similarly, a left-left image is generated. Third, the left-left and right-right images are multiplied sample-by-sample to form the final diffraction-based image. The key idea of this method is based on the fact that any dipping reflector exhibits a particular dip direction, so its subsurface image can exist either in the left-left or the right-right image, but not in both. As a result, the sample-by-sample multiplication of the two images eliminates the reflector images. Alternatively, because diffractions are generated by subsurface geologic features, which act as secondary sources and radiate in all directions, ranging from [Formula: see text] to 90°, their energy can exist in both images. After multiplication of both images, only the diffractors remain, whereas the reflectors are suppressed. Our method is applicable only for diffracting objects that radiate in all directions. An exception occurs when reflectors exhibit zero dip. In such a case, zero-dip reflectors could be present in both images and leak into the final diffractor image. We mitigate this problem in several ways, such as omitting near zero-offset input data, muting vertical-propagation components, or applying an [Formula: see text]-[Formula: see text] filter on the final diffraction image.

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Cho, Hyelim, Jaeyeon Kim, Seran Park, et al. "Demonstration of Solar Cell on a Graphite Sheet with Carbon Diffusion Barrier Evaluation." Molecules 25, no. 4 (2020): 785. http://dx.doi.org/10.3390/molecules25040785.

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An amorphous Si (a-Si) solar cell with a back reflector composed of zinc oxide (ZnO) and silver (Ag) is potentially the most plausible and flexible solar cell if a graphite sheet is used as the substrate. Graphite supplies lightness, conductivity and flexibility to devices. When a graphite sheet is used as the substrate, carbon can diffuse into the Ag layer in the subsequent p-i-n process at 200–400 °C. To prevent this, we added an oxide layer as a carbon diffusion barrier between the carbon substrate and the back reflector. For the carbon diffusion barrier, silicon oxide (SiO2) or tin oxide (SnOx) was used. We evaluated the thermal stability of the back reflector of a carbon substrate using secondary-ion mass spectrometry (SIMS) to analyze the carbon diffusion barrier material. We confirmed the deposition characteristics, reflectance and prevention of carbon diffusion with and without the barrier. Finally, the structures were incorporated into the solar cell and their performances compared. The results showed that the back reflectors that were connected to a carbon diffusion barrier presented better performance, and the reflector with an SnOx layer presented the best performance.

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Tsai, Yu-Hung, Hoang-Yan Lin, Mao-Kai Huang, Yuan-Zhen Zhuang, Yu-Hsin Huang, and Kuan-Heng Lin. "52‐3: Enhancing Micro‐LED Display Efficiency with Reduced Ambient Light Reflectance." SID Symposium Digest of Technical Papers 55, no. 1 (2024): 713–16. http://dx.doi.org/10.1002/sdtp.17625.

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Shrinking LEDs reduces Internal Quantum Efficiency (IQE) and challenges light collection[1]. This study employs LightTools® for geometric optical simulations to create a secondary optical structure with reflector and a black matrix, enhancing Micro‐LED efficiency. This approach significantly reduces light emission loss from the original 40% to 4.54%. and ambient light reflection from the original 25% to 4.85%.

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Zhang, Li, Changcheng Guo, Yazhu Zhang, et al. "Exploring Options for the Application of Azobenzene for Molecular Solar Thermal Energy Storage: Integration with Parabolic Trough Solar Systems." Energies 18, no. 9 (2025): 2298. https://doi.org/10.3390/en18092298.

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Molecular solar thermal (MOST) energy systems can be utilized for the absorption, storage, and release of energy from the ultraviolet (UV) band of the solar spectrum. In this study, we designed a molecular solar thermal energy storage and release device based on the photoisomerization reaction of azobenzene. The device was integrated with a parabolic trough solar system, broadening the absorption range of the solar spectrum. By utilizing a coated secondary reflector, the system achieved efficient reflection of ultraviolet (UV) light in the 290–490 nm range, while solid-state azobenzene enabled the conversion of photon energy into chemical energy for storage and release. Experimental results under winter outdoor conditions demonstrated that: the secondary reflector significantly enhanced UV light concentration; the molecular solar thermal energy device exhibited remarkable thermal efficiency. Under an average solar irradiance of 302.23 W·m−2, the device demonstrated excellent thermal performance, with the azobenzene reaching a peak temperature of 42.07 °C. The maximum heat release capacity was measured at 10.89 kJ·kg−1·m−1, while achieving a remarkable heat release power of 29.31 W·kg−1·m−1.

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Chen, Yi Cheng, and Chia Chi You. "Design of Secondary Optical Element for a Two-Reflector Solar Concentrator." Applied Mechanics and Materials 479-480 (December 2013): 161–65. http://dx.doi.org/10.4028/www.scientific.net/amm.479-480.161.

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This study explores the optimum design of secondary optical element (SOE) for a non-coplanar two-reflector solar concentrator. The non-coplanar solar concentrator comprises a primary parabolic mirror and a secondary hyperbolic mirror. Ray tracing simulation is adopted to investigate the optical performance, including the acceptance angle and the optical efficiency, of the solar concentrator with various designs of SOE. Finally, preliminary optimum designs of SOE are presented and discussed.

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Abbas, R., A. Sebastián, M. J. Montes, and M. Valdés. "Optical features of linear Fresnel collectors with different secondary reflector technologies." Applied Energy 232 (December 2018): 386–97. http://dx.doi.org/10.1016/j.apenergy.2018.09.224.

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P, Sundaram, and Senthil R. "THERMAL PERFORMANCE ENHANCEMENT OF SOLAR PARABOLIC TROUGH COLLECTOR USING SECONDARY REFLECTOR." International Journal of Engineering and Technology 8, no. 6 (2016): 2964–69. http://dx.doi.org/10.21817/ijet/2016/v8i6/160806412.

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Beltagy, Hani. "A secondary reflector geometry optimization of a Fresnel type solar concentrator." Energy Conversion and Management 284 (May 2023): 116974. http://dx.doi.org/10.1016/j.enconman.2023.116974.

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Zhu, Jing, Yan Liu, Lanling Lan, Yulong Tang, Yuanyuan Zhang, and Xiuhua Ma. "Solar side-pumped Nd-doped fiber laser based on a doughnut-shaped hollow reflector." Laser Physics Letters 20, no. 12 (2023): 125101. http://dx.doi.org/10.1088/1612-202x/ad0a70.

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Abstract A high-power solar side-pumped Nd-doped fiber laser based on a doughnut-shaped hollow reflector (DHR) is proposed. The primary concentrator consists of twelve off-axis parabolic mirrors. The DHR coupled with an array of three-dimensional compound parabolic concentrators (3D-CPCs) functions as the secondary concentrator, inside which many cycles of Nd-doped fiber is coiled. After being reflected by the off-axis parabolic mirrors, the sunlight is launched into the DHR through the twelve 3D-CPCs, and experiences multiple-times reflection by the DHR, and finally is absorbed by the Nd-doped fiber for laser oscillation. Ray tracing shows that 173-W of solar power can be absorbed by the fiber. By solving the rate equations and power transmission equations, laser output power, slope efficiency and optical-to-optical conversion efficiency of 10.3 W, 6.12% and 5.94%, respectively, are realized. This kind of solar-pumped fiber laser thus offers a new route for achieving high-power solar-pumped laser sources.

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Sobirin, Farhan Fatwa, Satia Nugraha, Fauzia Haz, and Peberlin Sitompul. "Study of Cassegrain-type antenna for radio telescope." Journal of Physics: Conference Series 2214, no. 1 (2022): 012028. http://dx.doi.org/10.1088/1742-6596/2214/1/012028.

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Abstract There are many critical parameters in the design of a radio telescope, such as antenna gain and antenna resolution. In telecommunications, radar, and radio telescopes, an antenna is a very important component. There are many designs of the antenna, such as dipole array and parabolic antenna. Parabolic antennas also have many sub-reflector and antenna methods that control the radio wave, such as the Cassegrain type. A Cassegrain-type antenna is a parabolic antenna in which the feed antenna is mounted at or behind the surface of the main parabolic reflector dish. For the transmitter system, the beam of radio waves from the feed antenna illuminates the secondary reflector (sub-reflector), which reflects it back to the main reflector dish and then forward to space. The Cassegrain design is widely used in parabolic antennas, for large antennas in satellite ground stations, communication satellites, and radio telescopes. In this paper discusses the design of a Cassegrain-type antenna for radio telescope, basic calculation, diameter size of the main reflector of 20 meters, the diameter size of sub-reflector of 2.5 meters, and frequency of 22 GHz and 43 GHz.

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Hills, Benjamin H., Knut Christianson, and Nicholas Holschuh. "A framework for attenuation method selection evaluated with ice-penetrating radar data at South Pole Lake." Annals of Glaciology 61, no. 81 (2020): 176–87. http://dx.doi.org/10.1017/aog.2020.32.

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AbstractAll radar power interpretations require a correction for attenuative losses. Moreover, radar attenuation is a proxy for ice-column properties, such as temperature and chemistry. Prior studies use either paired thermodynamic and conductivity models or the radar data themselves to calculate attenuation, but there is no standard method to do so; and, before now, there has been no robust methodological comparison. Here, we develop a framework meant to guide the implementation of empirical attenuation methods based on survey design and regional glaciological conditions. We divide the methods into the three main groups: (1) those that infer attenuation from a single reflector across many traces; (2) those that infer attenuation from multiple reflectors within one trace; and (3) those that infer attenuation by contrasting the measured power from primary and secondary reflections. To assess our framework, we introduce a new ground-based radar survey from South Pole Lake, comparing selected empirical methods to the expected attenuation from a temperature- and chemistry-dependent Arrhenius model. Based on the small surveyed area, lack of a sufficient calibration surface and low reflector relief, the attenuation methods that use multiple reflectors are most suitable at South Pole Lake.

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Nielsen, Carl Johan G., and André Preumont. "Adaptive Petal Reflector: In-Lab Software Configurable Optical Testing System Metrology and Modal Wavefront Reconstruction." Sensors 23, no. 17 (2023): 7316. http://dx.doi.org/10.3390/s23177316.

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This paper addresses two aspects of the metrology of spherical, petal polymer reflectors which are part of an effort by the European Space Agency (ESA) to develop actively controlled foldable reflectors, enabling larger apertures on CubeSats and small satellites. The first problem is that of measuring the surface figure error of the spherical reflector alone during the development phase, and to assess the quality before assembling the telescope (large stroke, low accuracy). The SCOTS (Software Configurable Optical Testing System) appears to provide a fast and satisfactory solution to this problem. The second problem is the wavefront error reconstruction when the petal reflector is mounted on the telescope, because parts of the petals are obscured by the secondary mirror, in such a way that the petals appear completely disconnected, making the gradient-based metrology impossible. Using the fact that the petals have common mechanical boundary conditions at the central support ring, the problem is solved by using a set of orthogonal modes satisfying the same boundary conditions. The vibration modes are used for this purpose; the modal amplitudes are reconstructed from slope data outside the obstruction, allowing for wavefront error reconstruction over the entire surface.

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Gao, Tie Cheng, Yan Jin Ai, and Xiu Yan Li. "Secondary Optical Design of LED Road Lights." Advanced Materials Research 301-303 (July 2011): 223–28. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.223.

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Aiming to the application of high-power LEDs in road lights, this article discusses the requirements of optical properties of LED road lights. It carries out the reflector-based secondary optical design of the selected LEDs, which is simulated with ASAP. The results show that this design can take full advantage of the optical properties of LED light sources, greatly improve the efficiency of LED road lights, and improve the uniformity of road lighting, so as to achieve the effects with which those effects produced from the traditional lights cannot be compared.

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Barbón, Arsenio, Covadonga Bayón-Cueli, José A. Fernández Rubiera, and Luis Bayón. "Theoretical Deduction of the Optimum Tilt Angles for Small-Scale Linear Fresnel Reflectors." Energies 14, no. 10 (2021): 2883. http://dx.doi.org/10.3390/en14102883.

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A theoretical justification and computation of the optimum values of the two longitudinal tilt angles of a small-scale linear Fresnel reflector is provided. The optimum angle of the mobile structure is proved to be half the latitude of the geographic location, while the optimum angle of the secondary reflector system is proved to be equal to that latitude. Brute-force verification is carried out for five EU cities, each in one of the five European climate zones.

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Choi, Jae-Seop, Tae-Yong Park, Bong-Geon Chae, and Hyun-Ung Oh. "Development of Lightweight 6 m Deployable Mesh Reflector Antenna Mechanisms Based on a Superelastic Shape Memory Alloy." Aerospace 11, no. 9 (2024): 738. http://dx.doi.org/10.3390/aerospace11090738.

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This paper describes the design and experimental verification of a 6 m parabolic deployable mesh reflector antenna mechanism based on a superelastic shape memory alloy. This antenna mainly consists of a deployable primary reflector with a superelastic shape memory alloy-based hinge mechanism and a fixed-type secondary reflector mast, where a rotary-type holding and release mechanism and deployment speed control system are installed. The main feature of this antenna is the application of a superelastic shape memory alloy to the mechanism, which has the advantages of plastic deformation resistance, high damping, and fatigue resistance. A shape memory alloy is applied to the hinge mechanism of each primary reflector rib and to the rotary-type holding and release mechanism as a deployment mechanism. In addition, a superelastic shape memory alloy wire is applied to the antenna in the circumferential direction to maintain the curvature of the primary reflector. The effectiveness of the proposed mechanism design was verified through repeated deployment tests on models of the superelastic shape memory alloy-based hinge mechanism and the antenna system.

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Regue, Hanane Maria, Belkacem Bouali, Toufik Benchatti, and Ahmed Benchatti. "Numerical Simulation of Conjugate Heat Transfer in a PTC with Secondary Reflector." International Journal of Heat and Technology 38, no. 1 (2020): 9–16. http://dx.doi.org/10.18280/ijht.380102.

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Zhu, Guangdong. "New adaptive method to optimize the secondary reflector of linear Fresnel collectors." Solar Energy 144 (March 2017): 117–26. http://dx.doi.org/10.1016/j.solener.2017.01.005.

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Bellos, Evangelos, Christos Tzivanidis, and Angelos Papadopoulos. "Secondary concentrator optimization of a linear Fresnel reflector using Bezier polynomial parametrization." Solar Energy 171 (September 2018): 716–27. http://dx.doi.org/10.1016/j.solener.2018.07.025.

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Bellos, Evangelos, and Christos Tzivanidis. "Investigation of a booster secondary reflector for a parabolic trough solar collector." Solar Energy 179 (February 2019): 174–85. http://dx.doi.org/10.1016/j.solener.2018.12.071.

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Inagaki, Akiya, Hiraku Sakamoto, Hiroaki Tanaka, Kosei Ishimura, and Masaaki Okuma. "P06 Shape control experiment using a prototype of smart reconfigurable secondary reflector." Proceedings of the Space Engineering Conference 2013.22 (2013): _P06–1_—_P06–2_. http://dx.doi.org/10.1299/jsmesec.2013.22._p06-1_.

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Fernández-García, Aránzazu, M. Elena Cantos-Soto, Marc Röger, Christian Wieckert, Christian Hutter, and Lucía Martínez-Arcos. "Durability of solar reflector materials for secondary concentrators used in CSP systems." Solar Energy Materials and Solar Cells 130 (November 2014): 51–63. http://dx.doi.org/10.1016/j.solmat.2014.06.043.

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Moran, Mark L., Roy J. Greenfield, and Steve A. Arcone. "Modeling GPR radiation and reflection characteristics for a complex temperate glacier bed." GEOPHYSICS 68, no. 2 (2003): 559–65. http://dx.doi.org/10.1190/1.1567225.

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We demonstrate that ground penetrating radar (GPR) reflection data from a temperate glacier are accurately modeled using a Helmholtz‐Kirchhoff diffraction integration technique that incorporates the radiation characteristics of point dipoles on a half‐space interface. This is accomplished by comparing field data to simulated data. Our 40‐MHz field data are from a 100 × 340 m (x‐ and y‐dimensions, respectively) survey grid containing 51 parallel survey lines. The field data were collected with the dipole oriented perpendicular to the survey line (x‐dipole). The synthetic data used isotropic, x‐dipole, and y‐dipole antennas, and reflections were calculated using a bed topography previously defined by 3D Kirchhoff migration. The comparisons between the real and synthetic waveforms show excellent agreement, including reflection arrival times, amplitude trends, interference patterns, and false layering from out‐of‐plane reflections. The location of reflectors determined from exploding reflector rays explains that bed reflections rapidly sink below background noise levels when reflections originate in the antenna's E‐plane. This occurs in both the simulated data and field data. Our results are of general importance for radio‐glaciology because they demonstrate that inappropriate dipole orientation with respect to the specular reflection point can lead to more than 12‐dB reduction in bottom reflection strength. Furthermore, a complicated bottom topography readily generates secondary, out‐of‐plane reflections that are easily confused with basal till layers.

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Ma, Jun, Cheng-Long Wang, Yuan Zhou, and Rui-Dong Wang. "Optimized design of a linear Fresnel collector with a compound parabolic secondary reflector." Renewable Energy 171 (June 2021): 141–48. http://dx.doi.org/10.1016/j.renene.2021.02.100.

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R. Senthil, R. Senthil. "Effect of Secondary Reflector on Thermal Performance of Linear Fresnel Concentrated Solar Collector." International Journal of Mechanical and Production Engineering Research and Development 8, no. 4 (2018): 943–50. http://dx.doi.org/10.24247/ijmperdaug201898.

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Zhu, Zhongyao, Ailing Tian, Bingcai Liu, Xin Du, and Suotao Dong. "Lightweight Design and Evaluation of Square Reflector." Applied Sciences 13, no. 16 (2023): 9160. http://dx.doi.org/10.3390/app13169160.

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In order to reduce the weight of optical elements in space remote sensors while increasing their stiffness, this paper takes an off-axis system secondary mirror as an example to design a square mirror with a size of 500 mm × 500 mm. The mirror adopts ultra-low expansion glass as the raw material. The paper proposed a lightweight form of gradual reinforcement and conducted the mirror assembly simulation analysis. The analysis results show that the weight of the lightweight mirror is 13.6 kg, and the surface density can reach 54.4 kg/m2. Under the circumstances of 1 g gravity and the temperature change of 15 °C~25 °C, the surface shape accuracy of the mirror assembly can reach 1/90λ (λ = 632.8 nm). Through the final testing, the first-order intrinsic frequency of the reflex mirror components is 167.8 Hz. The gap between the test results and the theoretical simulation results is less than 3%, which proves that the mirror assembly in the lightweight form of gradual reinforcement fully meets the index requirements and can provide a theoretical reference for the assembly of a mirror of similar size and type.

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Chen, Yi-Cheng, and Chia-Chi You. "Optimal Design of a Secondary Optical Element for a Noncoplanar Two-Reflector Solar Concentrator." International Journal of Photoenergy 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/861353.

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This paper presents the results of a parametric design process used to achieve an optimal secondary optical element (SOE) in a noncoplanar solar concentrator composed of two reflectors. The noncoplanar solar concentrator comprises a primary parabolic mirror (M1) and a secondary hyperbolic mirror (M2). The optical performance (i.e., acceptance angle, optical efficiency, and irradiance distribution) of concentrators with various SOEs was compared using ray-tracing simulation. The parametric design process for the SOE was divided into two phases, and an optimal SOE was obtained. The sensitivity to assembly errors of the solar concentrator when using the optimal SOE was studied and the findings are discussed.

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Minaeian, Ali, A. Alemrajabi, M. Chavoshi, A. Mostafaeipour, and Z. Seifi. "Effect of secondary reflector on solar flux intensity and uniformity of a Fresnel concentrator." Journal of Renewable and Sustainable Energy 12, no. 3 (2020): 033703. http://dx.doi.org/10.1063/5.0007604.

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Shaw, Dein, and Yan Ching Huang. "Design of a LED Module with Special Constraint." Applied Mechanics and Materials 284-287 (January 2013): 2704–10. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.2704.

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LED gradually replaces light source in many fields, it becomes more and more important. For the purpose of letting LED more effective, people usually use secondary optical lens to improve the optical quality. In this research, reflector and lens are used to compose a LED light module. In this study, a LED module is designed to meet the specific requirement of the illumination. It was found that changing lens thickness and lens position can improve the uniformity and the size of light patch. As a result, we found parameters about lens for best results. In the design process, we realized that uniformity can be increased by decreasing D10 value of the light. The best result of simulation was found (which are in the form of point data). We used polynomials to fit the contour of LED module of point data and used it to extend the reflector contour of calculated results. The size of light patch of LED contour with reflector-masked and point data is much smaller than with polynomials.

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Brix, Kolja, Yasemin Hafizogullari, and Andreas Platen. "Solving the Monge–Ampère equations for the inverse reflector problem." Mathematical Models and Methods in Applied Sciences 25, no. 05 (2015): 803–37. http://dx.doi.org/10.1142/s0218202515500190.

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The inverse reflector problem arises in geometrical nonimaging optics: given a light source and a target, the question is how to design a reflecting free-form surface such that a desired light density distribution is generated on the target, e.g. a projected image on a screen. This optical problem can mathematically be understood as a problem of optimal transport and equivalently be expressed by a secondary boundary value problem of the Monge–Ampère equation, which consists of a highly nonlinear partial differential equation of second order and constraints. In our approach the Monge–Ampère equation is numerically solved using a collocation method based on tensor-product B-splines, in which nested iteration techniques are applied to ensure the convergence of the nonlinear solver and to speed up the calculation. In the numerical method special care has to be taken for the constraint: it enters the discrete problem formulation via a Picard-type iteration. Numerical results are presented as well for benchmark problems for the standard Monge–Ampère equation as for the inverse reflector problem for various images. The designed reflector surfaces are validated by a forward simulation using ray tracing.

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Ying, Shang-Ping, Bing-Mau Chen, Han-Kuei Fu, and Chen-Yu Yeh. "Single Headlamp with Low- and High-Beam Light." Photonics 8, no. 2 (2021): 32. http://dx.doi.org/10.3390/photonics8020032.

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Generally, automobiles are typically equipped with separate headlamp lanterns for generating low- and high-beam light. Compared with separate headlamp lanterns, a single headlamp producing both low- and high-beam light can be more compact and have less mechanical complexity. The single headlamp structure has become a main emphasis of research that manufacturers will continue to focus great efforts on in the future. A novel design of a single headlamp generating both low- and high-beam light is proposed in this study. The proposed headlamp consists of a compound ellipsoidal reflector, a baffle plate, a condenser lens, and LED array devices generating low- and high-beam light. The compound ellipsoidal reflector comprises a primary ellipsoidal reflector for generating low-beam light and a secondary ellipsoidal reflector for generating high-beam light. Monte Carlo ray tracing simulations were performed to confirm the optical characteristics of the proposed design. A prototype of the proposed headlamp was also fabricated and assembled to verify the design’s effectiveness. The simulated and measured illuminance distributions of the low-beam and high-beam light had the desired light patterns. Moreover, all the simulated and measured illuminances of each point and line met the ECE R112 regulation for low-beam and high-beam light. The proposed headlamp in this study is feasible for the application of single headlamp generating both low- and high-beam light.

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García-Moreno, Jorge Moreno, Alaric Christian Montenon, Mihalis A. Nicolaou, Wojciech Lipiński, and Kypros Milidonis. "Artificial intelligence-aided generative design of non-imaging secondary reflector for linear Fresnel concentrating collector." Solar Energy 292 (May 2025): 113415. https://doi.org/10.1016/j.solener.2025.113415.

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Azarifar, Mohammad, Ceren Cengiz, and Mehmet Arik. "Optical and Thermal Analysis of Secondary Optics in Light Emitting Diodes’ Packaging: Analysis of MR16 Lamp." Journal of Physics: Conference Series 2116, no. 1 (2021): 012121. http://dx.doi.org/10.1088/1742-6596/2116/1/012121.

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Abstract Optical and thermal control are two main factors in package design process of lighting products, specifically light emitting diodes (LEDs). This research is aimed to study the role of secondary optics in opto-thermal characterization of LED packages. Novel thin total internal reflection (TIR) multifaceted reflector (MR) lens is modelled and optimized in Monte-Carlo ray-tracing simulations for MR16 package, regarded as one of the widely used LED lighting products. With criteria of designing an optical lens with 50% reduced thickness in comparison to commercially available lenses utilized in MR16 packages, nearly same light extraction efficiency and more uniform beam angles are achieved. Optical performance of the new lens is compared with the experimental results of the MR16 lamp with conventional lens. Only 2.3% reduction in maximum light intensity is obtained while lens size reduction was more than 25%. Based on the detailed CAD design, heat transfer simulations are performed comparing the lens thickness effect on heat dissipation of MR16 lamp. It was observed that using thinner lenses can reduce the lens and chip temperature, which can result in improved light quality and lifetime of both lens and light source.

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Banys-Paluchowski, Maggie, Steffi Hartmann, Jana de Boniface, et al. "Abstract PO3-23-03: Radar reflectors for marking of target lymph nodes in patients receiving neoadjuvant chemotherapy for breast cancer – a subgroup analysis of the prospective AXSANA (EUBREAST-03) trial." Cancer Research 84, no. 9_Supplement (2024): PO3–23–03—PO3–23–03. http://dx.doi.org/10.1158/1538-7445.sabcs23-po3-23-03.

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Abstract Background: Surgical staging procedures of the axilla in breast cancer patients converting from a clinically positive (cN+) to a clinically negative (ycN0) lymph node status during neoadjuvant chemotherapy (NACT) vary across countries and within individual countries. The international prospective AXSANA (EUBREAST-03) study aims at comparatively evaluating long-term outcomes of different staging procedures such as axillary lymph node dissection (ALND), sentinel lymph node biopsy (SLNB), target lymph node biopsy (TLNB) and targeted axillary dissection (TAD). The comparison of marking techniques for the target lymph node (TLN) is a secondary endpoint. In this subgroup analysis, we report on the largest yet prospective cohort of patients receiving a radar reflector for marking of the TLN prior to NACT. Methods: The AXSANA study is an international prospective cohort study including cN+ patients converting to ycN0 status and treated with different axillary staging techniques according to the standard at their treating institution. The study was initiated by the EUBREAST network and started enrollment in August 2020. Eligible patients have cT1-4c tumors, initially present with axillary lymph node metastasis and receive neoadjuvant chemotherapy. Patients converting to ycN0 status are followed up for 5 years irrespectively of the ypN status. In the present subgroup analysis, only patients with a TLN marked by a radar reflector were included. We prospectively examined the retrieval rate of radar reflectors and the identification rate of the TLN (defined as unequivocal removal of the lymph node, i.e., the presence of lymphatic tissue in the TLN specimen and/or pathological confirmation of post-NACT changes typical for metastatic lymph nodes responding to treatment). Results: A TLN was marked using a radar reflector in 74 patients prior to NACT. The median age was 52 years (range: 32-77). The most common subtype was no special type in 68 (92%) patients and invasive lobular cancer in 7 (7%) patients. Most patients (n = 44, 59%) had one suspicious node at time of diagnosis, followed by two (n = 15, 20%), three (n = 10, 14%) or ≥ four suspicious nodes (n = 5, 5%). Only one TLN was marked in 73 (99%) patients and two nodes were marked in one patient (1%). Fifteen patients (20%) had a MRI between marker placement and surgery. In 4 out of 15 cases (27%), MRI artifacts were described. However, the assessment of MRI was limited due to artifacts only in one out of these four patients (25%). Out of the 74 patients with radar reflector marked TLN, 45 (61%) had undergone final surgery at the time of analysis and 29 (39%) are still under NACT. 36 out of 45 patients (80%) who received final surgery converted to ycN0. Most patients had undergone a TAD (n = 41, 91%), followed by TLNB in 7% (n = 3) and upfront ALND in 2% of cases (n = 1). All radar reflectors were successfully removed. In 44 out of 45 patients (98%) the TLN was unequivocally identified and removed. In one patient the tissue specimen containing radar reflector consisted of fat tissue and no lymphatic tissue was identifiable, so it remains unclear whether the TLN was excised, or the reflector might have dislocated. 29 patients (65%) had converted to ypN0 status. Conclusion: To the best of our knowledge this is the largest prospective series of patients receiving a radar reflector for the marking of TLN prior to NACT for breast cancer. The removal rate of the marker and the detection rate of the target node were very high. Our data demonstrate that radar reflectors are a reliable tool for marking of target lymph nodes before neoadjuvant treatment. Citation Format: Maggie Banys-Paluchowski, Steffi Hartmann, Jana de Boniface, Oreste Davide Gentilini, Timo Basali, Elmar Stickeler, Michael Untch, Franziska Ruf, Sarah Fröhlich, Marc Thill, Michael P. Lux, Florentia Peintinger, Guldeniz Karadeniz Cakmak, Isabel Rubio, Michalis Kontos, Rosa Di Micco, Dawid Murawa, Ellen Schlichting, Bilge Aktas Sezen, Achim Rody, Dagmar Langanke, Nana Bündgen, Jose Ignacio Sanchez-Mendez, Renu Buss-Steidle, Christine Mau, Nana Buchmann, Sabine Riemer, Marit Helene Hansen, Nina Ditsch, Thorsten Kühn. Radar reflectors for marking of target lymph nodes in patients receiving neoadjuvant chemotherapy for breast cancer – a subgroup analysis of the prospective AXSANA (EUBREAST-03) trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-23-03.

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Kalidoss, P., S. Venkatachalapathy, and S. Suresh. "Optical and Thermal Properties of Therminol 55-TiO2 Nanofluids for Solar Energy Storage." International Journal of Photoenergy 2020 (January 22, 2020): 1–9. http://dx.doi.org/10.1155/2020/7085497.

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The present experimental study focuses on the energy storage performance of Therminol 55-TiO2 nanofluids for the absorption of solar energy. Photothermal conversion efficiency is enhanced using Fresnel lens and secondary reflectors with a glass-type evacuated absorber tube. The focal length of the Fresnel lens is 150 mm, and that of the secondary reflector is 70 mm. The optical absorbance, extinction coefficient, and thermal conductivity of nanofluids at 100, 250, 350, and 500 ppm are reported. The optical path length of the energy storage medium is 1 cm. The optical performance of the nanofluids is analyzed in the range of 400 to 800 nm. Compared to base fluid, the prepared concentrations show higher absorbance in the measured range of wavelength. The optimum concentration is found to be 250 ppm, and its specific heat is measured in the temperature range of 27 to 117°C and is found to vary from 1.85 to 2.19 J/g °C. The thermal conductivity of the maximum concentration of nanofluid is 0.134 W/mK. The optical absorbance test confirms the stability of nanofluids. Maximum temperature and photothermal conversion efficiency are obtained.

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de Wild, Jessica, Gizem Birant, Guy Brammertz, Marc Meuris, Jef Poortmans, and Bart Vermang. "Ultrathin Cu(In,Ga)Se2 Solar Cells with Ag/AlOx Passivating Back Reflector." Energies 14, no. 14 (2021): 4268. http://dx.doi.org/10.3390/en14144268.

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Ultrathin Cu(In,Ga)Se2 (CIGS) absorber layers of 550 nm were grown on Ag/AlOx stacks. The addition of the stack resulted in solar cells with improved fill factor, open circuit voltage and short circuit current density. The efficiency was increased from 7% to almost 12%. Photoluminescence (PL) and time resolved PL were improved, which was attributed to the passivating properties of AlOx. A current increase of almost 2 mA/cm2 was measured, due to increased light scattering and surface roughness. With time of flight—secondary ion mass spectroscopy, the elemental profiles were measured. It was found that the Ag is incorporated through the whole CIGS layer. Secondary electron microscopic images of the Mo back revealed residuals of the Ag/AlOx stack, which was confirmed by energy dispersive X-ray spectroscopy measurements. It is assumed to induce the increased surface roughness and scattering properties. At the front, large stains are visible for the cells with the Ag/AlOx back contact. An ammonia sulfide etching step was therefore applied on the bare absorber improving the efficiency further to 11.7%. It shows the potential of utilizing an Ag/AlOx stack at the back to improve both electrical and optical properties of ultrathin CIGS solar cells.

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Reda, Haddouche Mohammed, and Benazza Abdelylah. "Numerical Investigation and Solar Flux Distribution Analysis of Parabolic Trough Solar Collector by Adding Secondary Reflector." Instrumentation Mesure Métrologie 18, no. 3 (2019): 275–80. http://dx.doi.org/10.18280/i2m.180307.

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Rahbari, Meraj, Pouya Esfanjani, Ali Mahmoudi, and Mohammad Sadegh Valipour. "Performance enhancement of a parabolic dish collector with a novel receiver assisted with a secondary reflector." Solar Energy Materials and Solar Cells 283 (May 2025): 113464. https://doi.org/10.1016/j.solmat.2025.113464.

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Buendía-Martínez, Francisco, Florian Sutter, Sophie Gledhill, David Argüelles-Arízcun, Inmaculada Cañadas, and Aránzazu Fernández-García. "Innovative lifetime testing protocol for high-temperature secondary reflector materials used in concentrated solar thermal energies." Solar Energy Materials and Solar Cells 254 (June 2023): 112238. http://dx.doi.org/10.1016/j.solmat.2023.112238.

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Li, Hui, Xin Tan, Qingbin Jiao, et al. "Design and Study of a Reflector-Separated Light Dispersion-Compensated 3D Microscopy System." Sensors 23, no. 9 (2023): 4516. http://dx.doi.org/10.3390/s23094516.

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The secondary-phase grating-based tomographic microscopy system, which is widely used in the biological and life sciences, can observe all the sample multilayer image information simultaneously because it has multifocal points. However, chromatic aberration exists in the grating diffraction, which seriously affects the observation of the image. To correct the chromatic aberration of the tomographic microscope system, this paper proposes a system that adopts blazed gratings and angle-variable reflectors as chromatic aberration correction devices according to the principle of dispersion compensation and Fourier phase-shift theory. A reflector-separated light dispersion-compensated 3D microscopy system is presented to achieve chromatic aberration correction while solving the problem of multilayer image overlap. The theoretical verification and optical design of the system were completed using ZEMAX software. The results show that the proposed system reduced the chromatic aberration of ordinary tomographic microscopy systems by more than 90%, retaining more wavelengths of light information. In addition, the system had a relatively wide range in the color difference compensation element installation position, reducing the difficulty of dispersion compensation element installation. Overall, the results indicate that the proposed system is effective in reducing chromatic aberration in grating diffraction.

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Gledhill, Sophie, Kevin Steyer, Charlotte Weiss, and Christina Hildebrandt. "HiPIMS and DC Magnetron Sputter-Coated Silver Films for High-Temperature Durable Reflectors." Coatings 9, no. 10 (2019): 593. https://doi.org/10.3390/coatings9100593.

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High-temperature durable mirrors based on a protected silver sputter coating are attractive for secondary reflector applications in concentrated solar thermal power plants. In this paper, silver films are deposited by high-power impulse magnetron sputtering (HiPIMS) and standard direct current (DC) magnetron sputtering, either as exposed discretely deposited films or in-sequence-deposited thin film systems, where the silver is protected and embedded between adhesion and barrier layers. The unprotected silver films and equivalent protected silver thin film systems are compared and characterized as deposited and after 400 ºC oven temperature exposure. The reflectance is measured and grazing incident X-ray di raction (GIXRD) and scanning electron microscopy (SEM) pictures were taken. The HiPIMS silver film, sputtered with a peak current of 200 A and an approximately equivalent average power density to the DC magnetron sputtered silver, exhibits higher reflectance (and conductivity). Increasing the power density further, yields silver films with lower reflectance, correlating to a reduced grain size. In the protected silver film system, the reflectance does not improve, due to the presence of a less reflective top adhesion layer. The protected film system, with the 200 A HiPIMS, is, however, more durable at 400 C than the DC magnetron sputtered equivalent.

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Chun-Lin, Lu, and Li Dong-Ming. "Research on the Errors in Determination of Precise Optical Positions of Radio Sources." Symposium - International Astronomical Union 141 (1990): 499–500. http://dx.doi.org/10.1017/s0074180900087441.

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To link the optical reference frame to extragalactic radio frame, an observation program is in progress in Purple Mountain Observatory (PMO) and Shanghai Observatory. In this program, 70 extragalactic sources will be observed with the 1.56 m astrometric reflector in Shanghai. The secondary reference stars are determined with the twin astrograph (D = 40 cm, f = 300 cm) in PMO, and about 50 radio stars and some bright extragalactic sources will be observed with the twin astrograph.

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Chaitanya Prasad, G. S., K. S. Reddy, and T. Sundararajan. "Optimization of solar linear Fresnel reflector system with secondary concentrator for uniform flux distribution over absorber tube." Solar Energy 150 (July 2017): 1–12. http://dx.doi.org/10.1016/j.solener.2017.04.026.

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