Comparison of optical reflectance spectrum at blade and vein parts of cabbage and kale leaves

Abstract Explorations on a mixed metal phosphatoantimonate system led to the discovery of two new anhydrous phosphatoantimonates, namely, Cs4MSb6P4O28 (M=Mg, Zn), which represent the first examples of quinary AI – MII –SbV – PV– O systems. Single-crystal structure analysis reveals that the two title compounds crystallize in the tetragonal space group I41/a (No. 88). Their structures feature complicated 3D frameworks with interesting tunnel structures comprised of corner sharing MO4 tetrahedra, SbO6 octahedra and PO4 tetrahedra, with the Cs+ cations sitting in the tunnels to balance the valence. Optical reflectance spectrum measurements show that these two compounds are insulators with band gaps of about 4.5 eV.

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Optical Properties of Random Multilayers of Amorphous A-Si:H/A-Si3N4+x:H and the Classical Localization

MRS Proceedings ◽

10.1557/proc-219-831 ◽

1991 ◽

Vol 219 ◽

Cited By ~ 1

Author(s):

Shoji Nitta ◽

Kohji Ogawa ◽

Takehiro Furukawa ◽

Takashi Itoh ◽

Shuichi Nonomura

Keyword(s):

Light Propagation ◽

Reflectance Spectrum ◽

Localization Length ◽

The Other ◽

Absorption Coefficients ◽

Anomalous Peak ◽

Classical Localization ◽

Optical Reflectance Spectrum ◽

Reflectance Peak ◽

Average Layer Thickness

ABSTRACTIn the optical reflectance spectrum of the random multilayers of a-Si:H/a-Si3N4+x:H, it is observed an anomalous peak which is explained by the classical localization of light propagation. The following two subjects are discussed in this report; (a). The Kramers-Kronig transformation is done including the anomalous disorder-related reflectance peak. Extra absorption coefficients Δα are obtained by this analysis. Energy dependence of the localization length 1(hv) of light propagation are obtained by 1(hv)=1/Δα(hv). (b). The other is the experiment on scaling where the ratio of the disorder and the average layer thickness is kept constant but the size of each layer is changed in each experiment

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Study on the Low-Emissive Camouflage Pigment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.624.303 ◽

2012 ◽

Vol 624 ◽

pp. 303-306

Author(s):

Feng Chuan Shen ◽

Xin Xing Feng ◽

Tian Ma ◽

Jian Chun Zhang ◽

Hua Zhang ◽

...

Keyword(s):

Reflectance Spectrum ◽

Chemical Deposition ◽

Thermal Infrared ◽

Pure Metal ◽

Natural Grass ◽

Infrared Imager ◽

Coated Fabric ◽

Optical Reflectance Spectrum ◽

Chemical Deposition Method ◽

Thermal Infrared Imager

A low-emissive pigment of Al/SiO2/Fe2O3/FeO/Fe4[Fe(CN)6]3/Cr2O3/Cr (MAS) was prepared by chemical deposition method. The camouflage characteristics of the coated fabric with paint mixed with MAS, binder and other auxiliary in the thermal infrared (IR 8~14 um) and the optical (0.38~1.2 um) region, was studied by emissivity tester, visible light camera and thermal infrared imager. The results show that the MAS pigment has low emissivity and optical camouflage effectiveness compared with the Al/SiO2 pigment. Particularly, the MAS pigment is in green by depositing metal oxide, ferrocyanide and pure metal on the surface of Al/SiO2. The optical reflectance spectrum of coated fabric was similar to the natural grass. Furthermore, the surface emissivity of the coated fabric reached 0.51 in the IR region. The thermography of the coated fabric with 4 wt% MAS was similar to the natural grass. It can conclude that the coated fabric can perfectly imitate grass background.

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Surface Texturing of Si with Periodically Arrayed Oblique Nanopillars to Achieve Antireflection

Materials ◽

10.3390/ma14020380 ◽

2021 ◽

Vol 14 (2) ◽

pp. 380

Author(s):

Jun-Hyun Kim ◽

Sanghyun You ◽

Chang-Koo Kim

Keyword(s):

Aspect Ratio ◽

Plasma Etching ◽

Surface Texturing ◽

Light Reflection ◽

Si Substrate ◽

Weighted Mean ◽

Optical Reflectance ◽

Si Substrates ◽

Aspect Ratios ◽

Shadowing Effect

Si surfaces were texturized with periodically arrayed oblique nanopillars using slanted plasma etching, and their optical reflectance was measured. The weighted mean reflectance (Rw) of the nanopillar-arrayed Si substrate decreased monotonically with increasing angles of the nanopillars. This may have resulted from the increase in the aspect ratio of the trenches between the nanopillars at oblique angles due to the shadowing effect. When the aspect ratios of the trenches between the nanopillars at 0° (vertical) and 40° (oblique) were equal, the Rw of the Si substrates arrayed with nanopillars at 40° was lower than that at 0°. This study suggests that surface texturing of Si with oblique nanopillars reduces light reflection compared to using a conventional array of vertical nanopillars.

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Identification of pigments in artworks by inverse tangent derivative of spectrum and a new filtering method

Heritage Science ◽

10.1186/s40494-020-00438-4 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

F. Fazlali ◽

S. Gorji Kandi

Keyword(s):

Reflectance Spectrum ◽

Practical Method ◽

Chemical Methods ◽

Munk Function ◽

Absorption Of Light ◽

Spectrophotometric Data ◽

First Time ◽

Non Destructive ◽

Derivatives Of

Abstract Employing an economical and non-destructive method for identifying pigments utilized in artworks is a significant aspect for preserving their antiquity value. One of the non-destructive methods for this purpose is spectrophotometry, which is based on the selected absorption of light. Mathematical descriptive methods such as derivatives of the reflectance spectrum, the Kubelka–Munk function and logarithm have been employed for the characterization of the peak features corresponding to the spectrophotometric data. In the present study, the mentioned mathematical descriptive methods were investigated with the aim to characterize the constituents of an Iranian artwork but were not efficient for the samples. Therefore, inverse tangent derivative equation was developed on spectral data for the first time, providing considerable details in the profile of reflectance curves. In the next part, to have a simpler and more practical method it was suggested to use filters made up of pure pigments. By using these filters and placing them on the samples, imaging was done. Then, images of samples with and without filter were evaluated and pure pigments were distinguished. The mentioned methods were also used to identify pigments in a modern Iranian painting specimen. The results confirmed these methods with reliable answers indicating that physical methods (alongside chemical methods) can also be effective in determining the types of pigments.

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Optical Response Associated with the Orientation and Structure of Liquid Crystals with Respect to Phosphatidylcholine Concentration

Crystals ◽

10.3390/cryst11060678 ◽

2021 ◽

Vol 11 (6) ◽

pp. 678

Author(s):

Yuqi Han ◽

Yan Jiang ◽

Wei Guo ◽

Bing Li ◽

Lu Zhang ◽

...

Keyword(s):

Liquid Crystal ◽

Liquid Crystals ◽

Reflectance Spectrum ◽

Optical Response ◽

The Self ◽

Cholesteric Liquid Crystals ◽

Anchoring Effect ◽

Self Assembling ◽

Sensitization Effect ◽

Structure Of Liquid

Based on the anchoring effect due to the self-assembling behavior of the phospholipid molecules at the interface between the liquid crystal and water phases on the orientation of liquid crystals, the optical response associated with the orientation and structure of liquid crystals with respect to the concentration of 1,2-didodecanoyl-sn-glycero-3-phosphocholine solution has been investigated. The optical response owing to changes in the orientation and structure of the mixed cholesteric liquid crystals with respect to the change in the concentration of phosphatidylcholine has been obtained. Moreover, the feasibility of using as-prepared mixed cholesteric liquid crystals to measure the phosphatidylcholine concentration has been verified. A methodology to measure the reflectance spectrum by using mixed cholesteric liquid crystals to sensitize the phosphatidylcholine concentration has been further realized. The sensitization effect of the mixed cholesteric liquid crystals on the measurement of phosphatidylcholine concentration was also verified.

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