reflectance spectrum
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Author(s):  
Xiangxian Wang ◽  
Yaqian Ren ◽  
Tianxu Jia ◽  
Yingwen Su ◽  
Yunping Qi ◽  
...  

This paper presents a surface plasmon interference lithography technique based on the complementary grating, which comprises silicon gratings and complementary aluminum grating masks, for fabricating subwavelength structures. In this theoretical study, the optimal parameters of the complementary grating structure were determined using the reflectance spectrum. The optical field distributions of one- and two-dimensional subwavelength structures were obtained using the finite-difference time-domain method and rotation-related formulas. The results of numerical evaluations show that a one-dimensional periodic structure with a half-pitch resolution of 60.5 nm (approximately [Formula: see text]/6.7) can be fabricated. In addition, subwavelength structures can be diversified using different rotation methods to expose the photolithography samples, such as square dot arrays and quasi-hexagonal closely packed structures. The proposed method combines surface plasmon interference with sample rotation, thereby enabling fabrication of abundant subwavelength structures.


Author(s):  
Vladimir Ivanovski ◽  
Ireneusz Piwoński ◽  
Dariusz Guziejewski ◽  
Thomas G. Mayerhöfer

2021 ◽  
Author(s):  
Charlotte Brault ◽  
Juliette Lazerges ◽  
Agnès Doligez ◽  
Miguel Thomas ◽  
Martin Ecarnot ◽  
...  

Phenomic prediction has been defined as an alternative to genomic prediction by using spectra instead of molecular markers. A reflectance spectrum reflects the biochemical composition within a tissue, under genetic determinism. Thus, a relationship matrix built from spectra could potentially capture genetic signal. This new methodology has been successfully applied in several cereal species but little is known so far about its interest in perennial species. Besides, phenomic prediction has only been tested for a restricted set of traits, mainly related to yield or phenology. This study aims at applying phenomic prediction for the first time in grapevine, using spectra collected on two tissues and over two consecutive years, on two populations and for 15 traits. First, we characterized the genetic signal in spectra and under which condition it could be maximized, then phenomic predictive ability was compared to genomic predictive ability. We found that the co-inertia between spectra and genomic data was stable across tissues or years, but variable across populations, with co-inertia around 0.3 and 0.6 for diversity panel and half-diallel populations, respectively. Differences between populations were also observed for predictive ability of phenomic prediction, with an average of 0.27 for the diversity panel and 0.35 for the half-diallel. For both populations, there was a correlation across traits between predictive ability of genomic and phenomic prediction, with a slope around 1 and an intercept of -0.2, thus suggesting that phenomic prediction could be applied for any trait.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Benjamin N. L. Sharkey ◽  
Vishnu Reddy ◽  
Renu Malhotra ◽  
Audrey Thirouin ◽  
Olga Kuhn ◽  
...  

AbstractLittle is known about Earth quasi-satellites, a class of near-Earth small solar system bodies that orbit the sun but remain close to the Earth, because they are faint and difficult to observe. Here we use the Large Binocular Telescope (LBT) and the Lowell Discovery Telescope (LDT) to conduct a comprehensive physical characterization of quasi-satellite (469219) Kamoʻoalewa and assess its affinity with other groups of near-Earth objects. We find that (469219) Kamoʻoalewa rotates with a period of 28.3 (+1.8/−1.3) minutes and displays a reddened reflectance spectrum from 0.4–2.2 microns. This spectrum is indicative of a silicate-based composition, but with reddening beyond what is typically seen amongst asteroids in the inner solar system. We compare the spectrum to those of several material analogs and conclude that the best match is with lunar-like silicates. This interpretation implies extensive space weathering and raises the prospect that Kamo’oalewa could comprise lunar material.


Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6188
Author(s):  
Alexey Kokhanovskiy ◽  
Nikita Shabalov ◽  
Alexandr Dostovalov ◽  
Alexey Wolf

In this paper, we demonstrate the application of deep neural networks (DNNs) for processing the reflectance spectrum from a fiberoptic temperature sensor composed of densely inscribed fiber Bragg gratings (FBG). Such sensors are commonly avoided in practice since close arrangement of short FBGs results in distortion of the spectrum caused by mutual interference between gratings. In our work the temperature sensor contained 50 FBGs with the length of 0.95 mm, edge-to-edge distance of 0.05 mm and arranged in the 1500–1600 nm spectral range. Instead of solving the direct peak detection problem for distorted signal, we applied DNNs to predict temperature distribution from entire reflectance spectrum registered by the sensor. We propose an experimental calibration setup where the dense FBG sensor is located close to an array of sparse FBG sensors. The goal of DNNs is to predict the positions of the reflectance peaks of the reference sparse FBG sensors from the reflectance spectrum of the dense FBG sensor. We show that a convolution neural network is able to predict the positions of FBG reflectance peaks of sparse sensors with mean absolute error of 7.8 pm that is slightly higher than the hardware reused interrogator equal to 5 pm. We believe that dense FBG sensors assisted with DNNs have a high potential to increase spatial resolution and also extend the length of a fiber optical sensors.


Author(s):  
Sanjay B. Nagdeote

The Sr0.5Ba0.5Nb2O6 (SBN-50) is Synthesis by coprecipitation method in nanoscale. TG/DTA shows the reaction and tetragonal phase formation occur at low temperatures, due to which the good homogeneity and morphology of the particles is observed. The average size of the particles was found to be ~ 45 nm. The lattice parameters is found very close to the reported values of single crystals despite method of synthesis and size of the particles. A reflectance spectrum in UV and visible regions shows less reflectance for 337nm and 519nm respectively.


2021 ◽  
Vol 10 (3) ◽  
pp. xx-xx
Author(s):  
Mai Nguyen Thi Tuyet ◽  
Hue Dang Thi Minh ◽  
Huyen Tran Thi Thu ◽  
Lan Nguyen Thi ◽  
Nga Nguyen Kim ◽  
...  

The experiment had fabricated and studied the properties of ZnO and Cu doped ZnO nanoparticles with the change of the hexamethylene tetramine surfactant content (HMTA) with molar ratio Zn2 +: HMTA = 1: x; x = 1, 2 and 4. The methods were used to study the characteristics of materials such as: XRD, raman shift, SEM, reflection spectrum. The results show that, when the content of surfactant HMTA increased (1-4 mol versus the moles of Zn2+), the size of the nanorods crystals of fabricated materials had reduced from 64.5 to 21.7 nm. The reflectance spectrum of Cu doped ZnO materials samples was lower in the visible light region compared to pure ZnO samples. The photocatalytic properties for decomposition of methylene blue organic dye of the Cu doped ZnO sample (with the greatest concentration of HMTA surfactant of 4 mol versus the moles of Zn2+) reached 98% after 40 minutes of ultraviolet light irradiation, with the rate constant k= 0,13261 min-1.


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