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- 摘要
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Ultraviolet patterns of flowers revealed in polymer replica – caused by surface architecture
摘要： Angiosperms and their pollinators are adapted in a close co-evolution. For both the plants and pollinators, the functioning of the visual signaling system is highly relevant for survival. As the frequency range of visual perception in many insects extends into the ultraviolet (UV) region, UV-patterns of plants play an important role in the flower–pollinator interaction. It is well known that many flowers contain UV-absorbing pigments in their petal cells, which are localized in vacuoles. However, the contribution of the petal surface microarchitecture to UV-reflection remains uncertain. The correlation between the surface structure and its reflective properties is also relevant for biomimetic applications, for example, in the field of photovoltaics. Based on previous work, we selected three model species with distinct UV-patterns to explore the possible contribution of the surface architecture to the UV-signaling. Using a replication technique, we transferred the petal surface structure onto a transparent polymer. Upon illumination with UV-light, we observed structural-based patterns in the replicas that were surprisingly comparable to those of the original petals. For the first time, this experiment has shown that the parameters of the surface structure lead to an enhancement in the amount of absorbed UV-radiation. Spectrophotometric measurements revealed up to 50% less reflection in the UV-absorbing regions than in the UV-reflecting areas. A comparative characterization of the micromorphology of the UV-reflecting and UV-absorbing areas showed that, in principle, a hierarchical surface structure results in more absorption. Therefore, the results of our experiments demonstrate the structural-based amplification of UV-reflection and provide a starting point for the design of bioinspired antireflective and respectively strongly absorbing surfaces.
关键词： hierarchical structures,biomimetics,light absorption,light harvesting,light reflection
更新于2025-10-22 19:40:53
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Effect of Co component in Co-Ag granular thin films on visible-light reflection applied by magnetic field
摘要： The reflection of visible light (wavelength from 350 to 800 nm) on magnetic granular thin films Cox-Ag1-x with x from 0 to 35 at % was studied. Dependence of reflection (R) is strong on magnetic and percentage of Co in the thin films, R strongly increase in wavelengths 560 and 660 nm. In this paper, some arguments relating to the spin-plasmon phenomenon were used to explain the results.
关键词： spin-plasmon,Granular magnetic thin films,visible light,reflection
更新于2025-09-23 15:23:52
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Anthocyanin synthesis and light utilisation can be enhanced by reflective mulch – visualisation of light penetration into a tree canopy
摘要： With the increasing use of hailnets and decrease in light availability in the ripening period of apple fruit, insufficient light exposure often causes poor colouration viz anthocyanin synthesis on certain parts of the fruit and on certain fruit within the tree. The aim of this study was to investigate the potential of improving anthocyanin synthesis, in terms of fruit colouration, the major incentive for a consumer. Therefore, the reflective ground cover Lumilys? was spread between ‘Braeburn Mariri Red’ apple rows under a crystalline hailnet seven weeks prior to harvest and colour measured on 240 attached apple fruit. The reflective ground cover increased the reflected light by 1.6 to 3.9 times 1.0 m above ground. The improved light utilization led to an improved peel colouration, especially on the shaded side of the apple fruit and fruit in the lower inner part of the canopy, A coloured visualization from orange (high light intensity), yellow (medium) to green (low light intensity) as a result of the individual PAR measurements every 20 cm inside the canopy showed how the reflective mulch influences the light penetration into the different parts of the tree canopy.
关键词： reflective mulch,light reflection,anthocyanin,fruit quality,fruit colour,Apple (Malus domestica Borkh.),LumilysTM,hail net,climate change
更新于2025-09-23 15:19:57
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[IEEE 2018 Australasian Universities Power Engineering Conference (AUPEC) - Auckland, New Zealand (2018.11.27-2018.11.30)] 2018 Australasian Universities Power Engineering Conference (AUPEC) - Nano-structured GaAs Solar Cell Design, Simulation and Analysis for Conversion Efficiency Improvement
摘要： This paper discusses nano-structured GaAs solar cell design and analysis for conversion efficiency improvement by increasing the light transmission and absorption, reducing the light reflection. The focus of this research is to construct different type of nano-grating shaped GaAs solar cells with various nano-grating heights and pitches, to compare the simulation results and find a suitable nano-structure that can provide higher conversion efficiency. Finite difference time domain (FDTD) simulation tool is used to simulate and calculate transmission and absorption for different nano-grating shapes, such as, parabolic, triangular, trapezoidal and rectangular. Based on the simulation results, it has been confirmed that the light reflection of parabolic shaped nano-grating structures is higher than triangular nano-grating structures, but it is lower than rectangular and trapezoidal shaped nano-grating structures. Moreover, the simulation results confirmed that the light transmission of parabolic shaped nano-grating structures is about 62.3% having a 200-nm grating height and an 810-nm grating pitch, which is about 22% higher than the rectangular (i.e., flat) type substrates.
关键词： Finite-difference time-domain method,transmission,GaAs solar cells,and absorption,Nano-grating structure,Light reflection,Conversion efficiency,Solar or renewable energy
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE XXVI International Conference on Electronics, Electrical Engineering and Computing (INTERCON) - Lima, Peru (2019.8.12-2019.8.14)] 2019 IEEE XXVI International Conference on Electronics, Electrical Engineering and Computing (INTERCON) - Sunlight controlled reflection for lighting up a dark room
摘要： This project is focused on taking advantage of the light reflection in order to illuminate a dark room. In order to achieve this objective, a prototype was developed, which consists of a mirror mounted on a base with capabilities of rotating in the X and Y axis, a sensor that allows to know in which direction the sun is located and the necessary program code to maintain the illumination spot in the same position in a room, despite the movement of the sun through the day. Data was obtained through measurements, which allows to conclude that the energy invested in the prototype is lower than the energy needed to illuminate that room.
关键词： energy efficiency,light reflection,microcontroller
更新于2025-09-16 10:30:52