scholarly journals Polyester Fabric With Fluorescent Properties Using Microwave Technology For Anti-Counterfeiting Applications

2021 ◽  
Author(s):  
Fredj Saad ◽  
Ayda Baffoun ◽  
Boris Mahltig ◽  
Mohamed Hamdaoui
Keyword(s):  
Uv Light ◽  
Ultra Violet ◽  
Green Emission ◽  
Polyester Fabric ◽  
Fluorescent Properties ◽  
Microwave Technology ◽  
Uv Absorber ◽  
Yellow Coloration ◽  
Transmission Measurements ◽  
Light Resistance

Abstract The article presented concerns the application of fluorescein as a fluorescent material for anti-counterfeiting technology which will allow the labeling and identification of legitimate articles in the textile field. Fluorescein has been applied to polyester fabrics by microwave irradiation technique in the presence of a UV absorber. Thus, its presence in the textile substrate is detectable following an excitation at a specific wavelength belonging to the Ultra-violet zone, which makes this material very effective for tracking and detecting counterfeit articles. Fluorescent samples are characterized morphologically by scanning electron microscopy (SEM) and quantitatively by optical spectroscopy such as reflectance and transmission measurements. The treated samples show under UV light a yellowish green emission with a slight yellow coloration of the polyester fiber. The UV absorber applied to the fluorescent solution improves the light resistance of the treated samples by 25%. Their addition to the bath can also ensure the production of a protective fabric against UV.

scholarly journals Effect of Pre-Harvest Supplemental UV-A/Blue and Red/Blue LED Lighting on Lettuce Growth and Nutritional Quality

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 80
Author(s):  
Triston Hooks ◽  
Joseph Masabni ◽  
Ling Sun ◽  
Genhua Niu
Keyword(s):  
Blue Light ◽  
Nutritional Quality ◽  
Uv Light ◽  
Ultra Violet ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Daily Light Integral ◽  
Lettuce Growth ◽  
Supplemental Lighting

Blue light and ultra-violet (UV) light have been shown to influence plant growth, morphology, and quality. In this study, we investigated the effects of pre-harvest supplemental lighting using UV-A and blue (UV-A/Blue) light and red and blue (RB) light on growth and nutritional quality of lettuce grown hydroponically in two greenhouse experiments. The RB spectrum was applied pre-harvest for two days or nights, while the UV-A/Blue spectrum was applied pre-harvest for two or four days or nights. All pre-harvest supplemental lighting treatments had a same duration of 12 h with a photon flux density (PFD) of 171 μmol m−2 s−1. Results of both experiments showed that pre-harvest supplemental lighting using UV A/Blue or RB light can increase the growth and nutritional quality of lettuce grown hydroponically. The enhancement of lettuce growth and nutritional quality by the pre-harvest supplemental lighting was more effective under low daily light integral (DLI) compared to a high DLI and tended to be more effective when applied during the night, regardless of spectrum.

scholarly journals Research of Fluorescent Properties of a New Type of Phosphor with Mn2+-Doped Ca2SiO4

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2788
Author(s):  
Xiaozhou Fan ◽  
Wenqi Zhang ◽  
Fangcheng Lü ◽  
Yueyi Sui ◽  
Jiaxue Wang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Green Emission ◽  
Response Speed ◽  
Sintered Sample ◽  
Solid State Reaction Method ◽  
Average Lifetime ◽  
Diffraction Spectrum ◽  
Fluorescent Properties ◽  
Fluorescent Material ◽  
New Type

Fluorescent optical fiber temperature sensors have attracted extensive attention due to their strong anti-electromagnetic interference ability, good high-voltage insulation performance, and fast response speed. The fluorescent material of the sensor probe directly determines the temperature measurement effect. In this paper, a new type of fluorescent material with a Mn2+-doped Ca2SiO4 phosphor (CSO:Mn2+) is synthesized via the solid-state reaction method at 1450 °C. The X-ray diffraction spectrum shows that the sintered sample has a pure phase structure, although the diffraction peaks show a slight shift when dopants are added. The temperature dependence of the fluorescence intensity and lifetime in the range from 290 to 450 K is explored with the help of a fluorescence spectrometer. Green emission bands peaking at 475 and 550 nm from Mn2+ are observed in the fluorescence spectra, and the intensity of emitted light decreases as the temperature rises. The average lifetime of CSO:Mn2+ is 17 ms, which is much higher than the commonly used fluorescent materials on the market. The fluorescence lifetime decreases with increasing temperature and shows a good linear relationship within a certain temperature range. The research results are of great significance to the development of a new generation of fluorescence sensors.

Syntheses, crystal structures and photoluminescence properties of two rare-earth molybdates CsLn(MoO4)2 (Ln=Eu, Tb)

2018 ◽  
Vol 233 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Dan Zhao ◽  
Fa-Xue Ma ◽  
Bao-Zhong Liu ◽  
Yun-Chang Fan ◽  
Xue-Feng Han ◽  
...  
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Layer Structure ◽  
Green Emission ◽  
Salt Flux ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Light Excitation ◽  
Rare Earth Molybdates

AbstractSingle crystals of two cesium rare-earth molybdates CsLn(MoO4)2(Ln=Eu, Tb) have been prepared using the high temperature molten salt (flux) method. Single-crystal X-ray diffraction analyses reveal that they crystallize in the orthorhombic space groupPccm(No. 49) and features a 2D layer structure that is composed of [Ln(MoO4)2]∞and [Cs]∞layers. Under near-UV light excitation, emission spectrum of CsEu(MoO4)2consists of several sharp lines due to the characteristic electronic transitions of Eu3+ions, whereas CsTb(MoO4)2exhibits characteristic green emission of Tb3+ions.

Study on the Visual Response of Frankliniella occidentalis to Ultra Violet-Visible Spectroscopy with Different Wavelength Ranges

2021 ◽  
Vol 15 (4) ◽  
pp. 497-503
Author(s):  
Qihang Liu ◽  
Yueli Jiang ◽  
Mingqian Zhao ◽  
Jin Miao ◽  
Zhongjun Gong ◽  
...  
Keyword(s):  
White Light ◽  
Frankliniella Occidentalis ◽  
Uv Light ◽  
Ultra Violet ◽  
Western Flower Thrips ◽  
Selection Response ◽  
Visual Sensitivity ◽  
Light Energy ◽  
Visual Response ◽  
Response Effect

To understand the visual sensitivity of western flower thrips to 350–450 nm light, we examined thrips selective response effect and the effect of white light on thrips visual response effect. The results showed that the visual selection response to Ultra Violet (UV) light at 360–365 nm, the approach sensitivity to 380–385 nm light with 6000 lx was respectively the best (15.59, 7.26%), while under light energy, both of them to 360–365 nm light with 60 mW/cm2 were the best (20.04, 11.13%). Under contrast white light, the most sensitive UV spectra of thrips respectively caused by illumination, light energy was 380–385, 360–365 nm, and white light enhanced thrips visual response effect to UV light, which further increased by the increasing intensity, showing that under illumination, the visual response effect to 380–385 nm light with 6000 lx was the best (51.21,69.78%), while that to 360–365 nm light with 60 mW/cm2 were the best (43.98, 65.68%), originated from the different intensity spread by light energy and illumination. These results indicate that the change of photo-stimulus intensity property can regulated thrips visual sensitivity to enhance the phototactic effect.

scholarly journals Multifunctional Ionogels Incorporated with Lanthanide (Eu3+, Tb3+) Complexes Covalently Modified Multi-Walled Carbon Nanotubes

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1099 ◽  
Author(s):  
Qiuping Li
Keyword(s):  
Carbon Nanotubes ◽  
Ionic Liquids ◽  
Uv Light ◽  
Green Emission ◽  
Sem Images ◽  
Hybrid Gels ◽  
Multi Walled Carbon Nanotubes ◽  
Electric Materials ◽  
Walled Carbon Nanotubes ◽  
Functionalized Mwcnts

Ionogels refer to an emerging composite material made from the confinement of ionic liquids within some specific cross-linked network matrices. They have potential applications in areas such as electrochemical and optical-electric materials. Incorporation of lanthanide (Eu3+, Tb3+) complexes covalently functionalized multi-walled carbon nanotubes (MWCNTs) in ionogels provide new ideas to design and synthesize novel luminescent hybrid materials that have excellent characteristics of luminescence and ionic conductivity. Here, the multifunctional ionogels were synthesized by confining an ionic liquid and the rare earth functionalized MWCNTs in the cross-linked polymethyl methacrylate (PMMA) networks, resulting in a novel optical/electric multifunctional hybrid material. The SEM images and digital photographs suggest that the lanthanide functionalized MWCNTs are evenly dispersed in the hybrid matrices, thus leading to a certain transparency bulky gel. The resulting ionogels exhibit certain viscosity and flexibility, and display an intense red/green emission under UV-light irradiation. The intrinsic conductibility of the embedded ionic liquids and carbon nanotubes in conjunction with the outstanding photoluminescent properties of lanthanide complexes makes the soft hybrid gels a material with great potential and valuable application in the field of optical-electric materials.

Observations of TiO2 Surfaces Using Totally Reflected X-ray In-plane Diffraction Under UV Irradiation

2002 ◽  
Vol 751 ◽  
Author(s):  
T. Horiuchi ◽  
H. Ochi ◽  
K. Kaisei ◽  
K. Ishida ◽  
K. Matsushige
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Plane Surface ◽  
Signal To Noise Ratio ◽  
High Surface ◽  
Ultra Violet ◽  
High Signal ◽  
X Ray ◽  
Force Microscopy ◽  
Catalytic Activities

ABSTRACTSurface lattice displacements of titanium dioxide (TiO2: rutile) during ultra-violet (UV) light irradiation have been investigated using a total reflection x-ray diffraction, which provides a high signal to noise ratio (S/N) and superior in-plane surface diffraction. Under the environments in vapors of H2O, CH3OH, C2H5OH and C3H6OH, the photo-catalytic activities of TiO2 (110), (100) and (001) surfaces subject to UV irradiation have been measured. It is found that the diffraction peaks and their full width half maxima (FWHMs) show some peculiarities with respect to the photo-catalytic activities in both surface lattices and adsorbed molecules in vapors. Furthermore, Kelvin force microscopy (KFM) has showed that there exists a very high surface potential, probably due to surface atom displacements induced by UV irradiation. With regard to the origin of the photo-catalytic activities, the induced surface potentials are discussed.

scholarly journals Green Chemical Synthesis of N-Cholyl-L-Cysteine Encapsulated Gold Nanoclusters For Fluorometric Detection of Mercury Ions

2021 ◽  
Author(s):  
Kasthuri Jayapalan ◽  
Sivasamy Arumugam ◽  
Rajendiran Nagappan
Keyword(s):  
Uv Light ◽  
Stokes Shift ◽  
Gold Nanoclusters ◽  
Green Emission ◽  
Fluorescence Analysis ◽  
Cost Effective ◽  
Single Step ◽  
Fluorometric Detection ◽  
Transmission Electron ◽  
Green Chemical Synthesis

Abstract Here we report a simple, single-step, cost-effective, environmentally friendly, and biocompatible approach using sodium salt of N-cholyl-L-cysteine (NaCysC) capped gold nanoclusters (AuNCs) with green emission properties at above the CMC in aqueous medium under UV-light irradiation. The primary and secondary CMC of NaCysC was found to be 4.6 and 10.7 mM respectively using pyrene as fluorescent probe. The synthesized AuNCs exhibit strong emission maxima at 520 nm upon excitation of 375 nm with a large Stokes shift of 145 nm. The surface functionality and morphology of NCs are studied by Fourier transform infrared spectroscopy, dymanic light scattering studies and transmission electron microscopy. The formation of AuNCs was completed within 5 h and exhibit high stability for more than 6 months. The NaCysC templated AuNCs selectively quenches the Hg2+ ions with higher sensitivity in aqueous solution over the other metal ions. The fluorescence analysis of Hg2+ showed a wide linear range from 15 to 120 µM and a detection limit was found to be 15 nM.

scholarly journals DAYA PATOGENESITAS Helicoverpa armigera Nuclear Polyhedrosis Virus HaNPV SETELAH TERKENA RADIASI SINAR ULTRAVIOLET

2000 ◽  
Vol 6 (1) ◽  
pp. 65-70
Author(s):  
Mahanani Tri Asri ◽  
Isnawati Isnawati
Keyword(s):  
Biological Control ◽  
Helicoverpa Armigera ◽  
Nuclear Polyhedrosis Virus ◽  
Uv Light ◽  
Ultra Violet ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Helicoverpa Armígera ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis

This research is about pathogen capacity of the Helicoverpa armigera nuclear Polyhedrosis Virus (HaNPV) after irradiation by ultra violet (UV) light. The HaNPV is the one kind of the virus which attack the insect Helicoverpa armigera-attacker the some species of the crop life tobacco, cotton, potato, tomato. Because of that the HaNPV can be used as the biological control of the pest. Some researcher stated that the pathogen capacity of the HaNPV is decrease if the virus was expose in the ultra violet (UV) light. Because of the fact the virus in not useful as the biological control of the pest in the land corp. This research to test the statement. Laboratory experimental was done to tested the pathogen capacity of the HaNPV after irradiation treatment by the ultra violet light. The intensity of the UV light in this experiment were 28.7 lux, 97.3 lux, and 127.4 lux with the lighting period were 0, 1, 3, 6, 9, 12, and 15. The result of the research stated that the pathogen capacity of the HaNPV was not influenced by ultra violet light. So the virus is still useful as the biological control of the pest in the land crop.

Study on Photochromic Materials with a Novel Photochromic Diarylethene use for Polarization Holographic Recording

2013 ◽  
Vol 763 ◽  
pp. 61-64 ◽  
Author(s):  
Shang Hua He ◽  
Gang Liu ◽  
Shi Qiang Cui
Keyword(s):  
Fluorescence Spectra ◽  
Uv Light ◽  
Amorphous Film ◽  
Quantum Yields ◽  
Holographic Recording ◽  
Pmma Film ◽  
Recording Medium ◽  
Fluorescent Properties ◽  
Image Recording ◽  
Photochromic Materials

A novel unsymmetrical photochromic diarylethene 1-(2, 5-dimethyl-3-thienyl)-2-[2-methyl-5-(2,2-dibutylfluorene)-3-thienyperfluorocyclo-pentene (1o) was synthesized and its photochromic and fluorescent properties were investigated. Diarylethene 1 changed the color from colorless to hyacinthine upon irradiation with 297 nm UV light, in which absorption maxima were observed at 554 nm in hexane and at 565 nm in PMMA amorphous film, respectively. This new photochromic system also exhibited remarkable fluorescence intensity both in solution and in PMMA film. The fluorescence spectra showed a systematic red-shift with the emission intensity of diarylethene 1 in a photo-stationary state was quenched to ca. 64%. The cyclization and cycloreversion quantum yields of 1 in hexane were determined to be 0.56 and 0.002. Polarization multiplexed image recording can be carried out in this diarylethene 1c/PMMA film as recording medium film.

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