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Distinguishing between closely related species of Allium and of Brassicaceae by narrowband hyperspectral imagery
摘要： Classification of crop species is an actively studied topic in remote sensing using multi-spectral image sensors. Unfortunately, the spectral bands available in the multispectral imagery are broad and limited in number to classify the crop species. In this paper, we propose optimal spectral bands to classify Allium (garlic and onion) and Brassicaceae (Chinese cabbage and radish) by using higher-dimensional data from hyperspectral imagery. A decision-tree classifier was used to determine the optimal method to use the high-dimensional data. The high-dimensional data were analysed for all growth stages and considering bandwidths with different full width at half maximum (FWHM) values at 25, 40, 50 and 80 nm. The spectral bands selected for Allium were differentiated into green, blue, and NIR bands for each growth stage. The results show that Allium can be classified clearly as overall accuracy (OA) 1 and kappa coefficient 1 for all FWHM based on March 22 data. For each April 19 and May 12 data, the decision-tree classifier with each 80 nm FWHM and 50 nm FWHM yielded a better classification accuracy of more than OA 0.921 and kappa coefficient 0.839 than other FWHM. The spectral bands selected for Brassicaceae were found to be similar to blue band for all growth stages. Brassicaceae was classified clearly for all FWHM based on October 27 data. Also, Brassicaceae was classified clearly for 25 nm FWHM based on November 25 data and OA, kappa coefficient for 40 nm FWHM and 50 nm FWHM are high as 0.974, 0.947 respectively.
关键词： Decision-tree classifier,Hyperspectral imagery,Classification,Full width at half maximum,Spectral band
更新于2025-09-23 15:23:52
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Acid(g)/base(g)-controlled reversible ????1/2 of absorption spectrum of a functional dye film
摘要： UV–Vis absorption full width at half maximum (FWHM) plays a significant role not only in describing spectral shapes but also in determining the use of organic dyes for a particular application. For example, organic dyes with a relatively wide absorption FWHM are beneficial with respect to enhancing photon absorption efficiency of solar cells, whereas, for improving color purity in optical filters, narrow FWHM is desirable. Despite such a critical role, studies examining the modulation of absorption FWHM from an organic dye in the solid state are relatively lacking. In this work, we suggest rapid, simple, and effective method to control the absorption FWHM of a squarylium-based dye (SQ) film using an organic solvent vapor. Alternative treatments of base/acid gas to the SQ film (2.0 s for each gas) resulted in reversible absorption FWHM (D FWHM: 121 nm). From the systematic optical and morphology characterizations, it was revealed that changes in FWHM originated from reversible molecular arrangements between monomer-type and H-aggregate-type of SQ by efficient base/acid vapor diffusion into the SQ film. Moreover, the modulation exhibited high fatigue resistance against repeated gas treatments, which secures its practical applications. These results suggest that the proposed simple gas-treatment process in this work is beneficial for the efficient modulation of absorption FWHM of various organic dyes.
关键词： gas treatment,aggregation,organic dyes,full width at half maximum,monomer,absorption spectrum
更新于2025-09-23 15:19:57
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Zinc Oxo Clusters Improve the Optoelectronic Properties on Indium Phosphide Quantum Dots
摘要： This study explored the effect of zinc precursors on the optical properties of InP quantum dots (QDs) by controlling the reactivity of zinc carboxylates via a simple thermal treatment. The formation of zinc oxo clusters, Zn4O(oleate)6 and Zn7O2(oleate)10, during the thermal decomposition of zinc oleate was confirmed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. By using the zinc oxo clusters as reaction precursors, high-quality InP QDs with high photoluminescence quantum yield (PLQY) and narrow full width at half maximum (FWHM) were synthesized. (Green QDs: PLQY=95%, FWHM=37 nm. Red QDs: PLQY=84%, FWHM=40 nm) The analysis results showed that the improved optoelectronic properties were achieved by two important functions of the zinc oxo clusters: 1) suppressing the rapid depletion of the highly reactive phosphorus source and inducing size uniformity of the In(Zn)P core, and 2) facilitating the formation of an oxidized buffer layer, which effectively controls defects. Likewise, the use of reactivity-controlled species is an effective strategy for the synthesis of well-designed QDs.
关键词： full width at half maximum,InP quantum dots,optoelectronic properties,photoluminescence quantum yield,zinc oxo clusters
更新于2025-09-23 15:19:57
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Enhanced performance of SnSe-Graphene hybrid photonic surface plasmon refractive sensor for biosensing applications
摘要： In this study, we developed a simple hybrid structure and an appropriate numerical analysis method for a prism-based surface plasmon refractive index biosensor by using an angular interrogation domain technique. The performance parameters were determined in terms of the sensitivity, detection accuracy (DA), and quality factor (QF). The results demonstrated the improved overall performance of the proposed method. The proposed sensor comprised a prism filled with a hybrid of gold (Au), alpha tin selenide (α-SnSe), and graphene, and a sensing medium. Monolayers of α-SnSe with a similar structure to graphene and phosphorene have exceptional optoelectronic properties and they have attracted much attention as two-dimensional (2D) materials in a similar manner to other 2D material family members. and its sensitivity was higher than those of previously reported sensors. All of the performance parameters were enhanced for this hybrid sensor, which is not possible with sensors based only on graphene. Increasing the number of graphene-only layers improved the sensitivity but decreased the DA and QF. The effect of the electric field distribution on the inserted graphene layers was analyzed with the finite difference time domain (FDTD) technique using Lumerical FDTD solution commercial software. The proposed biosensor may facilitate novel sensing applications.
关键词： full width at half maximum,sensitivity,SnSe,surface plasmon refractive sensor,graphene
更新于2025-09-19 17:13:59