Fluorescence Spectral Imaging as a Tool for Locating Uranium Deposited on Surfaces

2009 ◽  
Author(s):  
David L. Monts ◽  
Guangjun Wang ◽  
Yi Su ◽  
Ping-Rey Jang ◽  
Charles A. Waggoner
Keyword(s):  
Bandpass Filter ◽  
Uv Light ◽  
Visible Region ◽  
Spectral Imaging ◽  
Spectral Information ◽  
Uranyl Compounds ◽  
Uranium Compounds ◽  
Field Samples ◽  
Quantitative Fluorescence ◽  
Metallic Uranium

In the environment, metallic uranium readily oxidizes to form uranium compounds that contain the uranyl (UO2+2) moiety. For more than a hundred and fifty years, it has been known that when illuminated with ultraviolet (UV) light, uranyl compounds exhibit characteristic fluorescence in the visible region (450–650 nm). We report our efforts to develop a transportable, quantitative Fluorescence Spectral Imaging (FSI) system as a tool for locating and quantifying uranyl compounds dispersed in soils and on other surfaces. A project is underway to develop a set of sensors to locate expended depleted uranium (DU) rounds and to process soil and debris to recover the material from domestic firing ranges. The FSI system can also be utilized to monitor excavation of DU munitions and separation of uranyl compounds from soils. FSI images are acquired by illuminating a surface with a UV light and using a narrow bandpass filter on a camera, recording an image of the resulting fluorescence. The FSI image provides both spatial and spectral information. The FSI system is described and its performance characterized using field samples.

scholarly journals Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms

2019 ◽  
Vol 15 ◽  
pp. 2344-2354 ◽  
Author(s):  
A Lennart Schleper ◽  
Mariano L Bossi ◽  
Vladimir N Belov ◽  
Stefan W Hell
Keyword(s):  
Visible Light ◽  
Single Molecule ◽  
Ring Opening ◽  
Uv Light ◽  
Visible Region ◽  
Super Resolution ◽  
Ring Closure ◽  
Low Emission ◽  
Fluorescence Modulation ◽  
High Degree

We present a new series of photochromic 1,2-bis(2-ethylbenzo[b]thiophen-3-yl)perfluorocyclopentenes with an oxidized benzothiophene core (O) or a nonoxidized one, decorated with mono- (Th1) and bithiophene (Th2) units attached to positions 6 and 6′ (Sy = symmetric) or only to position 6 (As = asymmetric). “Oxidized” compounds have highly fluorescent closed forms emitting in the visible region (yellow to red). The dyes with nonoxidized benzothiophenes possess fluorescent open forms with rather low emission efficiency. The photoswitching kinetics was studied at several wavelengths with UV and visible light. New diarylethenes underwent ring-closure reactions by irradiation with UV light (365 nm, 405 nm), and the reversible ring-opening by irradiation with visible light (470 nm, 530 nm). The on-switching of fluorescence due to the ring-closure reaction was observed also with visible light of 470 nm (to an extent of 10% for compound SyOTh 1 ) and attributed to the Urbach tail effect. Due to a high degree of fluorescence modulation (>270), good fatigue resistance and large fluorescence quantum yield, compound SyOTh 1 emerged as a candidate for single-molecule based super-resolution fluorescence microscopy.

K3Eu5(PO4)6: hydrothermal synthesis, crystal structure and photoluminescence properties

2019 ◽  
Vol 75 (7) ◽  
pp. 883-890 ◽  
Author(s):  
Ya-Li Xue ◽  
Ai-Yun Zhang ◽  
Xiao-Yang Han ◽  
Xiao-Qi Cui ◽  
Ling Deng ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Uv Light ◽  
Three Dimensional ◽  
Visible Region ◽  
Monoclinic Space Group ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Strong Luminescence ◽  
Light Excitation

An anhydrous orthophosphate, K3Eu5(PO4)6 (tripotassium pentaeuropium hexaphosphate), has been prepared by a high-temperature solid-state reaction combined with hydrothermal synthesis, and its crystal structure was determined by single-crystal X-ray diffraction analysis (SC-XRD). The results show that the compound crystallizes in the monoclinic space group C2/c and the structure features a three-dimensional framework of [Eu5(PO4)6]∞, with the tunnel filled by K+ ions. The IR spectrum, UV–Vis spectrum and luminescence properties of polycrystalline samples of K3Eu5(PO4)6, annealed at temperatures of 650, 700, 750, 800 and 850 °C, were investigated. Although with a full Eu3+ concentration (9.96 × 1021 ions cm−3), the self-activated phosphor K3Eu5(PO4)6 shows s strong luminescence emission intensity with a quantum yield of 37%. Under near-UV light excitation (393 nm), the series of samples shows the characteristic emissions of Eu3+ ions in the visible region from 575 to 715 nm. The sample sintered at 800 °C gives the strongest emission and its lifetime sintered at 800 °C (1.88 ms) is also the longest of all.

scholarly journals Preparation of ternary ZnO/Ag/cellulose and its enhanced photocatalytic degradation property on phenol and benzene in VOCs

2019 ◽  
Vol 17 (1) ◽  
pp. 779-787 ◽  
Author(s):  
Xiao-Hang Zou ◽  
Si-Wei Zhao ◽  
Ji-Guo Zhang ◽  
Hui-Liang Sun ◽  
Qing-Jiang Pan ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Separation Efficiency ◽  
Uv Light ◽  
Low Cost ◽  
Visible Region ◽  
X Ray Diffraction ◽  
Ternary Composite ◽  
Photogenerated Electrons ◽  
Excellent Photocatalytic Activity ◽  
Diffraction Patterns

AbstractThe ZnO/Ag/cellulose composite (ZAC) with excellent photocatalytic activity of degrading benzene and phenol in VOCs has been successfully synthesized. EDS, TEM, XPS and UV-vis analyses show that the ZAC is a ternary composite. It is composed of Ag, ZnO and cellulose, where the cellulose works as the substrate to anchor the other two components. The X-ray diffraction patterns find well-crystallized ZnO nanoparticles. Multiple PL peaks in the visible region measured for ZAC, imply rich defects on ZnO. It is observed that Ag nanoparticles are mainly attached on ZnO in the composite, which would raise the separation efficiency of photogenerated electrons and holes. Photocatalytic degradation shows that ZAC is able to decompose almost 100% phenol and 19% benzene in VOCs under UV light irradiation (6 W) which is almost no harm to human body. Due to the renewable cellulose, our ternary composite ZAC imparts low-cost, easily recycled and flexible merits, which might be applied in the indoor VOCs treatment.

The Optical Properties of Ammonia Treated TiO2 Nanostructure Prepared by Liquid Phase Deposition Method

2011 ◽  
Vol 364 ◽  
pp. 470-474
Author(s):  
Siti Khatijah Md Saad ◽  
Akrajas Ali Umar ◽  
Mohd Yusri Abd Rahman ◽  
Muhamad Mat Salleh
Keyword(s):  
Optical Properties ◽  
Solar Cell ◽  
Liquid Phase ◽  
Nitrogen Doping ◽  
Uv Light ◽  
Visible Region ◽  
Liquid Phase Deposition ◽  
Paper Report ◽  
Solar Cell Application ◽  
Percentage Concentration

. TiO2 was known for its potential in solar cell and photocatalyst application. However the usage of anatase TiO2 in solar cell application has its own disadvantage as TiO2 spectrum was limited to ultraviolet (UV) light limiting its application. It was found that the broader optical absorption of TiO2 can be obtained by nitrogen doping. This paper report the optical properties study of ammonia treated TiO2 nanostructures with various percentage concentration of ammonia. The TiO2 nanostructures was prepared by liquid phase deposition (LPD) method using on ITO substrate and annealed at 450 °C for 1h. The TiO2 nanostructures were characterized with rod-like morphology with length and diameter of ca. 100 nm and ca. 100 nm respectively that vertically oriented on the surface. The optical properties of the samples exhibit strong band near the UV region. The optical properties drastically changed if the samples treated with ammonia, of which exhibit the present of broader absorption band in the visible region. The TiO2 treated ammonia should be find used in photoelectrochemical (PEC) solar cell application.

Probing the magnetic5fdensity of states above the Fermi level in metallic uranium compounds by x-ray magnetic circular dichroism

1999 ◽  
Vol 60 (15) ◽  
pp. 10606-10609 ◽  
Author(s):  
P. Dalmas de Réotier ◽  
A. Yaouanc ◽  
G. van der Laan ◽  
N. Kernavanois ◽  
J.-P. Sanchez ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Fermi Level ◽  
Magnetic Circular Dichroism ◽  
X Ray ◽  
Uranium Compounds ◽  
Circular Dichroïsm ◽  
Metallic Uranium

scholarly journals Photostabilization of rubberwood using cerium oxide nanoparticles. Part 1: Characterization and colour changes

Les/Wood ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 57-70
Author(s):  
Kavyashree Srinivasa ◽  
Krishna Kumar Pandey ◽  
Marko Petrič
Keyword(s):  
Cerium Oxide ◽  
Uv Light ◽  
Light Exposure ◽  
Visible Region ◽  
Accelerated Weathering ◽  
Uva Light ◽  
Nanoparticles Concentration ◽  
Colour Changes ◽  
Good Transparency ◽  
Harmful Radiation

Light induced darkening and deterioration of wood used outdoors is undesirable. Photoprotection of wood could be achieved by using additives that reflect or absorb harmful radiation responsible for degradation. Nano metal oxides have strong absorption in the UV range of solar radiation and good transparency in the visible region. They offer unique benefits in protecting coatings and coated substrates from being degraded by UV radiation. However, to exploit the properties of nanoparticles, homogenous dispersion without agglomeration is necessary. In the present work, the photostabilization of rubberwood surfaces coated with cerium oxide (CeO2) was studied. The nanoparticles were surface functionalized with an organic alkoxy silane (3-glycidyloxypropyltrimethoxy silane) to improve the homogenous distribution in coatings, and the modified nanoparticles were dispersed in isopropanol and polyurethane (PU) coating. Rubberwood surfaces coated with dispersed nanoparticles (concentration 0.5 % to 6 % w/v) were exposed to a fluorescent UVA light source (λ=340 nm) at 60 °C in an accelerated weathering tester for 500 h and 1000 h. Colour changes due to UV light exposure were monitored using a spectrocolourimeter. Dispersion of CeO2 nanoparticles in PU coatings (concentration >2 %) restricted the photoyellowing of wood polymers.

Physically unclonable security patterns created by electrospinning, and authenticated by two-step validation method

2021 ◽  
Author(s):  
Didem Taşcıoğlu ◽  
Arda Atçı ◽  
Seçil SEVİM ÜNLÜTÜRK ◽  
Serdar Ozcelik
Keyword(s):  
Social Problem ◽  
Uv Light ◽  
Spectral Information ◽  
Second Step ◽  
Spectral Signature ◽  
Fiber Network ◽  
Security Patterns ◽  
Electrospinning Method ◽  
Security Pattern ◽  
Random Patterns

Abstract Counterfeiting is a growing economic and social problem. For anticounterfeiting, random and inimitable droplet/fiber patterns were created by the electrospinning method as security tags that are detectable under UV light but invisible in daylight. To check the authenticity of the original security patterns created; images were collected with a simple smartphone microscope and a database of the recorded original patterns was created. The originality of the random patterns was checked by comparing them with the patterns recorded in the database. In addition, the spectral signature of the patterns in the droplet/fiber network was obtained with a simple and hand-held spectrometer. Thus, by reading the spectral signature from the pattern, the spectral information of the photoluminescent nanoparticles was verified and thus a second-step verification was established. In this way, anticounterfeiting technology that combines ink formula, unclonable security pattern creation and two-level verification is developed.

scholarly journals p-n Based Photoelectrochemical Device for Water Splitting Application Alpha-Hematite (α-Fe2O3)-Titanium Dioxide (tio2) as N-Electrode & Polyhexylthiophene (rrphth) - Nanodiamond (ND) as P-Electrode

MRS Advances ◽  
2018 ◽  
Vol 3 (13) ◽  
pp. 697-706
Author(s):  
Hussein Alrobei ◽  
Hye Young Lee ◽  
Ashok Kumar ◽  
Manoj K. Ram
Keyword(s):  
Titanium Dioxide ◽  
Water Splitting ◽  
Uv Light ◽  
Visible Region ◽  
Visible Spectrum ◽  
Clean Energy ◽  
Weight Percentage ◽  
Production Of Hydrogen ◽  
Electron Hole Pair ◽  
Physical And Chemical

ABSTRACTRecently, photoelectrochemical (PEC) water splitting using semiconductor photoanode has received great attention due production of hydrogen through clean energy. The alpha hematite (α Fe2O3) is one of the candidate amongst photoanodic materials, which is chemically stable, abundant in nature with a band gap of 2.0-2. 2eV allowing to be harvesting in the visible light. However, it has also drawn back due to high recombination rate of electron–hole pair revealing the low concentration of charges and lower device performance. In common with α-Fe2O3, the titanium dioxide (TiO2) has been known as one of the most explored photoanode electrode material due to its physical and chemical stability in aqueous and non-toxicity. However, TiO2 has large bandgap (3.0-3.2 eV) that results in absorbing UV light and very small part of visible region. Incorporation of TiO2 in α-Fe2O3 could achieve better efficiencies as photoanode materials by enhancing the electric conductivity, limited hole diffusion length, and both materials can absorb light in both UV and visible spectrum range. However, the photoanodic properties of α-Fe2O3 with different concentrations of TiO2 are mostly unknown. Under this work, α-Fe2O3-TiO2 nanomaterial was synthesized using a hydrothermal method. The α-Fe2O3-TiO2 nanomaterials containing different weight percentage (2.5, 5, 16, 25, and 50) of TiO2 to α-Fe2O3 were characterized using SEM, XRD, UV-Vis, FTIR and Raman techniques, respectively. The electrochemical properties of α-Fe2O3-TiO2 nanomaterials were investigated by cyclic voltammetry and chronoamperometry techniques, respectively.

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