Toward Perovskite-Related Scintillators with Necessary Stokes Shift and Thickness for Hard X-Ray Radiography and Gamma Spectroscopy

2022 ◽  
pp. 1-34
Author(s):  
Weronika W. Wolszczak ◽  
David L. Carroll ◽  
Richard T. Williams
Keyword(s):  
Gamma Spectroscopy ◽  
Stokes Shift ◽  
X Ray

scholarly journals Synthesis of Exosome-Based Fluorescent Gold Nanoclusters for Cellular Imaging Applications

2021 ◽  
Vol 22 (9) ◽  
pp. 4433
Author(s):  
Eun Sung Lee ◽  
Byung Seok Cha ◽  
Seokjoon Kim ◽  
Ki Soo Park
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Stokes Shift ◽  
Gold Nanoclusters ◽  
Human Colon ◽  
Cellular Imaging ◽  
Metal Nanoclusters ◽  
Human Colon Cancer ◽  
X Ray ◽  
High Concentrations

In recent years, fluorescent metal nanoclusters have been used to develop bioimaging and sensing technology. Notably, protein-templated fluorescent gold nanoclusters (AuNCs) are attracting interest due to their excellent fluorescence properties and biocompatibility. Herein, we used an exosome template to synthesize AuNCs in an eco-friendly manner that required neither harsh conditions nor toxic chemicals. Specifically, we used a neutral (pH 7) and alkaline (pH 11.5) pH to synthesize two different exosome-based AuNCs (exo-AuNCs) with independent blue and red emission. Using field-emission scanning electron microscopy, energy dispersive X-ray microanalysis, nanoparticle tracking analysis, and X-ray photoelectron spectroscopy, we demonstrated that AuNCs were successfully formed in the exosomes. Red-emitting exo-AuNCs were found to have a larger Stokes shift and a stronger fluorescence intensity than the blue-emitting exo-AuNCs. Both exo-AuNCs were compatible with MCF-7 (human breast cancer), HeLa (human cervical cancer), and HT29 (human colon cancer) cells, although blue-emitting exo-AuNCs were cytotoxic at high concentrations (≥5 mg/mL). Red-emitting exo-AuNCs successfully stained the nucleus and were compatible with membrane-staining dyes. This is the first study to use exosomes to synthesize fluorescent nanomaterials for cellular imaging applications. As exosomes are naturally produced via secretion from almost all types of cell, the proposed method could serve as a strategy for low-cost production of versatile nanomaterials.

Al-rich industrial residues for mineral binders in ESEE region

2020 ◽  
Author(s):  
Katarina Šter ◽  
Sabina Kramar
Keyword(s):  
Power Plants ◽  
Raw Materials ◽  
Gamma Spectroscopy ◽  
Thermal Power ◽  
Raw Material ◽  
Recycling Rate ◽  
Low Carbon ◽  
X Ray ◽  
Industrial Residues ◽  
Essential Components

<p>Al-rich mineral resources are one of the essential components for the production of the novel sustainable mineral binders. Belite-sulfoaluminate (BCSA) cements, which are considered as low-carbon and low-energy, allows the substitution of natural raw materials with secondary ones. In East-Southeast European countries (ESEE) there are huge amounts of various industrial and mine residues that are either landfilled or currently have a low recycling rate. These residues are generated from mining activities (mine waste) and as a by product of different types of industry, such as thermal power plants, steel plants or the aluminium industry (slags, ashes, red mud, etc.). Within the framework of the RIS-ALiCE project, in cooperation with 15 project partners from Slovenia, Austria, France, Hungary, Serbia, Bosnia and Herzegovina and Macedonia, a network of relevant stakeholders has been established in the field of currently unused aluminium-containing mine and industrial residues. Inside the created network mine and industrial residues have been mapped and valorised in order to evaluate their suitability for the use in innovative and sustainable low CO<sub>2</sub>-mineral binder production. Aluminium-containing residues are characterized with respect to their chemical, physical and radiological composition using different analytical methods such as X ray fluorescence spectroscopy, ICP optical emission spectrophotometry, gravimetry, X ray powder diffraction, gamma spectroscopy, etc. The long-term activity of network between wastes holders/producers and mineral end users will be enabled via developed Al-rich residues registry, including a study of the potential technological, economic and environmental impacts of applying the innovative methodology of the sustainable secondary raw materials management in ESEE region. Developed registry with the data valuable for both, waste providers as waste users in ESEE region, can be later-on upscaled also to other regions of Europe. It will provide the data on the available and appropriate Al-rich secondary resources, which will enablethe production of innovative low-CO<sub>2 </sub>cements.</p><p><strong>Keywords:</strong> secondary raw material, alternative binders, Al-rich residues, networking, mapping, valorisation, registry.</p>

The electronic structure and the photoluminescence property of the photocatalyst BaZn1/3Nb2/3O3

2007 ◽  
Vol 22 (8) ◽  
pp. 2185-2188 ◽  
Author(s):  
B. Xu ◽  
W.F. Zhang ◽  
X.Y. Liu ◽  
J. Yin ◽  
Z.G. Liu
Keyword(s):  
Electronic Structure ◽  
Conduction Band ◽  
Function Theory ◽  
Stokes Shift ◽  
Photoluminescence Property ◽  
X Ray Diffraction ◽  
Phonon Interaction ◽  
Strong Electron ◽  
X Ray ◽  
Electron Phonon Interaction

The photocatalyst BaZn1/3Nb2/3O3 with ABO3 perovskite structure has been synthesized by using a solid-state reaction process. It was characterized by x-ray diffraction and photoluminescence spectroscopy. The luminescence band centers around 285 nm and shows a large Stokes shift compared with the excitation spectrum, indicating a strong electron–phonon interaction in the photocatalyst BaZn1/3Nb2/3O3. The electronic structure of BaZn1/3Nb2/3O3 was calculated by using the pseudopotential method of the density function theory. It shows that the conduction band should be mainly composed of the Nb 4d states, and the valence band should be mainly composed of the O 2p state. The densities of the O 2p states and the Zn 4s states at the bottom of the conduction band are very low. The Zn 4s states show an expanded structure, which was proposed to be helpful for the migration of the photoexcited carriers, thus favoring the photocatalytic activity of BaZn1/3Nb2/3O3.

scholarly journals Evaluation of Ionizing Radiation in Five Private Radiology Centers in Khuzestan

2020 ◽  
Author(s):  
Behzad Fouladi Dehaghi ◽  
Jamileh Deris ◽  
Maryam Mosavi Qahfarokhi ◽  
Ameneh Golbaghi ◽  
Leila Nematpour
Keyword(s):  
Radiation Dose ◽  
Ionizing Radiation ◽  
Gamma Spectroscopy ◽  
Surface Radiation ◽  
Annual Dose ◽  
Waiting Room ◽  
X Ray ◽  
Medicine Research ◽  
Ionization Radiation ◽  
Diagnostic Radiography

Background: Nowadays ionizing radiation is widely used in medicine, research and industry. In medicine, ionizing radiation is used to diagnose diseases and in high doses to treat diseases such as cancer. Undoubtedly, most exposure to artificial sources is in the field of medical and diagnostic radiology. Therefore, practitioners in the field of diagnostic radiography and patients are exposed to ionizing radiation and its risks. On the other hand, despite the advantages and efficacy of diagnostic radiation in the medical field, overall less attention is paid to optimizing and controlling protection in medical radiation. Therefore, the aim of this study was to evaluate the background ionizing radiation in Ahwaz diagnostic radiography centers. Methods: Ionization radiation levels were measured in and out of each center using gamma spectroscopy (Radiation Alert Inspector-EXP 15109) at a, b, c, d and e radiographic centers within one meter above the Earth's surface. Radiation levels within each center were measured at four locations (outside of center, secretary desk, and patient waiting room and behind the radiology room) both in X-ray machine operating and non-operating condition. The obtained data were analyzed by SPSS software.  Results: The inside ionization radiation dose in a, b, c, d and e radiographic centers were 0.121, 0.119, 0.126, 0132 and 0.128 μSv/h respectively. The outside ionization radiation dose in a, b, c, d and e radiographic centers were 0.094, 0.092, 0.093, 0.112 and 0.101 μSv/h respectively. Equivalent annual dose within and outside selected radiology centers were lower than the threshold (1 mSv / year). Conclusion: The results show that the ionizing radiation dose of the X-ray equipment examined in the radiology centers of Ahwaz is lower than the global standard.

An Examination of Neutron Induced Autoradiography and Gamma Spectroscopy for the Study of Paintings

1988 ◽  
Vol 123 ◽  
Author(s):  
J.S. Olin ◽  
D.W. Von Endt ◽  
Y.T. Cheng ◽  
M. Ligeza
Keyword(s):  
Gamma Rays ◽  
Gamma Spectroscopy ◽  
Close Contact ◽  
Charged Particles ◽  
Distribution Patterns ◽  
X Rays ◽  
Radiographic Film ◽  
X Ray ◽  
Radioactive Nuclides ◽  
The Subject

Neutron-induced autoradiography is a further step in the development of techniques for the examination of paintings that complements x-ray radiography and often yields unique information that cannot be obtained by other means. After exposure to a field of thermal neutrons (<0.3eV), selected elements in the painting form radioactive nuclides that in turn decay at known half-lives with the emission of gamma rays and charged particles. The charged particles, mainly electrons, expose radiographic film that is held in close contact with the painting by a very slight vacuum. Unlike x-ray radiography, which involves detecting x-rays that have passed through the painting to expose a film, autoradiography uses one activation with neutrons followed by sequential film exposures to capture the images of activated elements that have different half-lives. The autoradiographs show the distribution patterns of the pigments in which the elements occur. These pigments may be on the surface and visible in the painting or they may be beneath the surface. Often autoradiography uncovers the preliminary sketch or underpainting preceding the rough blocking in of the subject and the subsequent paint layers that create the final image. X-rays reveal almost exclusively the presence of pigments containing heavy elements such as lead and barium; autoradiography identifies the presence of activated pigments and distinguishes the fine details of paint application as well as changes in composition.

High solid-state luminescence in propeller-shaped AIE-active pyridine–ketoiminate–boron complexes

2015 ◽  
Vol 13 (20) ◽  
pp. 5775-5782 ◽  
Author(s):  
Yanping Wu ◽  
Zhenyu Li ◽  
Qingsong Liu ◽  
Xiaoqing Wang ◽  
Hui Yan ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Solid State ◽  
Quantum Yield ◽  
Stokes Shift ◽  
Electronic Structure Calculations ◽  
High Quantum Yield ◽  
X Ray ◽  
Boron Complexes ◽  
Structure Calculations ◽  
State Luminescence

Two pyridine-ketoiminate-based organoboron complexes were demonstrated to possess aggregation-induced emission, large Stokes shift and high quantum yield in the solid-state, which were rationalized through X-ray crystal analysis and electronic structure calculations.

scholarly journals Gamma signatures of the C-BORD Tagged Neutron Inspection System

2018 ◽  
Vol 170 ◽  
pp. 07011 ◽  
Author(s):  
A. Sardet ◽  
B. Pérot ◽  
C. Carasco ◽  
G. Sannié ◽  
S. Moretto ◽  
...  
Keyword(s):  
Energy Spectrum ◽  
Gamma Spectroscopy ◽  
Fast Neutrons ◽  
Inspection System ◽  
Pure Element ◽  
Material Identification ◽  
X Ray ◽  
Chemical Threats ◽  
The Eu ◽  
Cargo Containers

In the frame of C-BORD project (H2020 program of the EU), a Rapidly relocatable Tagged Neutron Inspection System (RRTNIS) is being developed to non-intrusively detect explosives, chemical threats, and other illicit goods in cargo containers. Material identification is performed through gamma spectroscopy, using twenty NaI detectors and four LaBr3 detectors, to determine the different elements composing the inspected item from their specific gamma signatures induced by fast neutrons. This is performed using an unfolding algorithm to decompose the energy spectrum of a suspect item, selected by X-ray radiography and on which the RRTNIS inspection is focused, on a database of pure element gamma signatures. This paper reports on simulated signatures for the NaI and LaBr3 detectors, constructed using the MCNP6 code. First experimental spectra of a few elements of interest are also presented.

scholarly journals Determining Excited-State Structures and Photophysical Properties in Phenylphosphine Rhenium(I) Diimine Biscarbonyl Complexes Using Time-Resolved Infrared and X-ray Absorption Spectroscopies

2021 ◽  
Author(s):  
Yuushi Shimoda ◽  
Kiyoshi Miyata ◽  
Masataka Funaki ◽  
Tatsuki Morimoto ◽  
Shunsuke Nozawa ◽  
...  
Keyword(s):  
Excited State ◽  
Photophysical Properties ◽  
Stokes Shift ◽  
Combination Method ◽  
Acetonitrile Solution ◽  
Structural Factors ◽  
Time Resolved ◽  
X Ray ◽  
Time Resolved Infrared Spectroscopy ◽  
X Ray Absorption

We have explored the structural factors on the photophysical properties in two rhenium(I) diimine complexes in acetonitrile solution, cis,trans-[Re(dmb)(CO)<sub>2</sub>(PPh<sub>2</sub>Et)<sub>2</sub>]+ (Et(2,2)) and cis,trans-[Re(dmb)(CO)<sub>2</sub>(PPh<sub>3</sub>)<sub>2</sub>]+ ((3,3)) (dmb = 4,4'-dimethyl-2,2'-bipyridine, Ph = phenyl, Et = ethyl) using the combination method of time-resolved infrared spectroscopy, time-resolved extended X-ray absorption fine structure, and quantum chemical calculations. The difference between these complexes is the number of phenyl groups in the phosphine ligand, and this only indirectly affects the central Re(I). Despite this minor difference, the complexes exhibit large differences in emission wavelength and excited-state lifetime. Upon photoexcitation, the bond length of Re-P and angle of P-Re-P are significantly changed in both complexes, while the phenyl groups are largely rotated by ~20º only in (3,3). We concluded that the instability from steric effects of phenyl groups and diimine leads to the smaller Stokes shift of the lowest excited triplet state (T<sub>1</sub>) in (3,3). The large structural change between the ground and excited states causes the longer lifetime of T<sub>1</sub> in (3,3).

A Study of the Photoluminescence and Reflectivity Spectra of MOCVD Grown MnSe

1994 ◽  
Vol 340 ◽  
Author(s):  
M. Di Blasio ◽  
L. Aigouy ◽  
M. Averous ◽  
J. Calas ◽  
P. Tomasini ◽  
...  
Keyword(s):  
Energy Gap ◽  
Stokes Shift ◽  
Thin Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zinc Blende ◽  
Reflectivity Spectra ◽  
Different Temperatures ◽  
First Time ◽  
Zinc Blende Structure

Photoluminescence (PL) experiments at 2K are performed on MOCVD grown MnSe. The precursors used in the growth stage are methylpentacarbonylmanganese and diethylselenide. Pyrolysis of the percursors is realized inside a gradient reactor under a constant H2 flux, between 280-55°TC. The compound is epitaxially grown on various substrates (Si, InP, GaSb, GaAs, ZnTe/GaAs, etc.). On some of these samples the compound presents a zinc blende structure, while in the other samples rock salt formation has been identified. The first substrate is used because of its interest in Si technology, while the others are used because MnSe can be grown in the zinc blende phase for very thin layers. For the first time x-ray diffraction data has allowed us to determine the lattice constant of zincblende MnSe (aMnse (oct)=5.818Å), confirming the close approximation (a ∼ 5.9Å) used from the Zn1-xMnxSe alloy. These compounds have visible Mn++ transitions at 2.12-5eV; other features are also visible at 2.3-4, 2.7, and 3.0eV. The energy gap transition of tetrahedral thin film layers of MnSe is seen for the first time in PL spectra. A temperature dependant PL study is performed on MnSe in the 2-200K range. Reflectivity experiments are used to attempt to identify the internal manganese transitions. A qualitative PL analysis of the samples grown at different temperatures and on different substrates is provided. A Stokes shift is encountered when the results are compared.

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