Changes in structural and optical properties due to γ-irradiation of MgO nanoparticles

AbstractIn this research, the influence of γ-irradiation on the optical and structural properties of magnesium oxide (MgO) nanoparticles was studied. The MgO nanoparticles were irradiated with doses 100 Gy, 1 kGy, 10 kGy and 20 kGy from 60Co source. The as-synthesized samples of MgO nanoparticles prepared by the sol-gel technique were analyzed by XRD which suggested the double phase; cubic and hexagonal structures of the material. The crystal defects that produced in the cubic and hexagonal lattice were studied before and after 60Co γ-irradiation in a gamma cell by different dose rates in order to report the changes in structural properties of the MgO nanoparticles. The irradiated and un-irradiated samples were characterized by XRD and UV–Vis. The XRD pattern of MgO nanoparticles is showed that the crystal size of MgO nanoparticles being increased with increasing the γ-ray dose rate. For optical absorption, the UV–Visible absorption spectra of MgO nanoparticles are showed that when the dose rate is increased, the value of band gap is decreased. Also, the experimental values of the mass attenuation coefficient of MgO nanoparticles have been calculated before and after γ-irradiation by using the gamma spectroscopy method. Therefore, the results are showed that γ-ray irradiation has various effects on structural, morphological and optical properties.

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Effect of gamma irradiation on the structure characteristics and mass attenuation coefficient of MgO nanoparticles

Radiochimica Acta ◽

10.1515/ract-2018-2924 ◽

2018 ◽

Vol 106 (10) ◽

pp. 857-864 ◽

Cited By ~ 2

Author(s):

Maryam Amini ◽

Alireza Vejdani Noghreiyan ◽

Zahra Dehghani ◽

Mohammad Hossein Majles Ara

Keyword(s):

Gamma Irradiation ◽

Band Gap ◽

Attenuation Coefficient ◽

Hexagonal Lattice ◽

Mass Attenuation Coefficient ◽

Crystal Defects ◽

Mgo Nanoparticles ◽

Before And After ◽

Structure Properties ◽

Mass Attenuation

Abstract In this work, the structure properties and mass attenuation coefficient of MgO nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of MgO nanoparticles by sol–gel method were analyzed by XRD which suggested the double phase; cubic and hexagonal structures of the material. Crystal defects produced in the cubic and hexagonal lattice were studied before and after exposure to 20 kGy gamma irradiation in order to investigate the changes in the structure properties and mass attenuation coefficients of MgO nanoparticles. XRD data of gamma-irradiated and non-irradiated MgO nanoparticles show that the crystal size of MgO nanoparticles increases after radiation exposure. SEM images after irradiation indicated significant changes in the morphology. The UV-Visible absorption spectra of the nanoparticles were taken and the results of optical band gap of the MgO nanoparticles before and after irradiation show that the value of band gap has changed slightly due to gamma irradiation. The results of comparing experimental values of mass attenuation coefficient for non-irradiated MgO nanoparticles with theoretical values of mass attenuation coefficient for MgO microparticles calculated using the NIST XCOM show that the mass attenuation coefficient not only depends on the effective atomic number but also depends on the size of the particles. Also, it is observed that the mass attenuation coefficient of MgO nanoparticles decreases after the irradiation which shows that by increasing the size of the nanoparticles, the mass attenuation coefficient decreases. It could be because the cross-section of photon interaction with materials depends on the surface to volume ratio of nanoparticles. The experimental results also show that the linear and mass attenuation coefficient of MgO nanoparticles decrease with increasing the photon energy.

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Optical and structural properties of Li2O–Al2O3–B2O3 glasses before and after γ-irradiation effects

Journal of Applied Physics ◽

10.1063/1.3003070 ◽

2008 ◽

Vol 104 (10) ◽

pp. 103515 ◽

Cited By ~ 30

Author(s):

D. Singh ◽

K. Singh ◽

B. S. Bajwa ◽

G. S. Mudahar ◽

D. P. Singh ◽

...

Keyword(s):

Structural Properties ◽

Irradiation Effects ◽

Γ Irradiation ◽

Before And After

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Effect of Buffer on the Optical Properties of Irradiated Hydroxyethyl Methacrylate Copolymer

Journal of Materials Research ◽

10.1557/jmr.2002.0177 ◽

2002 ◽

Vol 17 (5) ◽

pp. 1199-1207

Author(s):

K. F. Chou ◽

C. C. Han ◽

Sanboh Lee

Keyword(s):

Optical Properties ◽

Irradiation Dose ◽

Ph Value ◽

Bathochromic Shift ◽

Cutoff Wavelength ◽

Hydroxyethyl Methacrylate ◽

Γ Irradiation ◽

Incident Wavelength ◽

Γ Ray ◽

Methacrylate Copolymer

The effect of buffer and γ irradiation on the optical properties of hydroxyethyl methacrylate (HEMA) copolymer was investigated. The transmission of HEMA copolymer decreased with the increase of irradiation dose and/or pH value of the buffer. The cutoff wavelength of HEMA copolymer exhibits a bathochromic shift as the γ-ray dose and/or pH value of buffer increases. The influence of atmosphere during γ-ray irradiation on the optical properties of HEMA copolymer was investigated. The change of optical properties of HEMA copolymer irradiated in air was more pronounced than that irradiated in vacuum. Light was scattered by holes in the polymer. The relationship between scattering intensity (Is) and incident wavelength (λ) can be described by the formula Is ∝ λ−n. The span of holes increases with the irradiation dose regardless of radiation atmosphere and pH value in the range of 4.1–6.5. A boundary between the inner and outer layers of HEMA copolymer irradiated in air was observed, separating two differential morphologies of holes.

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Effects of Different Irradiation Treatments on Total Saponins Content of Sapindus mukorossi

Dose-Response ◽

10.1177/15593258211062781 ◽

2022 ◽

Vol 20 (1) ◽

pp. 155932582110627

Author(s):

Yu-Min Shi ◽

Heng Yan ◽

Lin-Sen Wu ◽

Jia-Jia Xie ◽

Hong-Guo Chen

Keyword(s):

Crude Extract ◽

Low Dose ◽

Reference Data ◽

Biological Activities ◽

Radical Scavenging ◽

Ionic Surfactant ◽

Γ Irradiation ◽

Before And After ◽

Γ Ray ◽

Further Development

Sapindus mukorossi Gaertn is also known as Mu Huanzi, You Huanzi, soap tree, etc. The pericarp of Sapindus mukorossi contains many saponins, which is a type of natural non-ionic surfactant. Its extract has vigorous surface activity and biological activities such as bacteriostasis, oxidation resistance, and free radical scavenging. The Sapindus mukorossi extract is an environmentally friendly washing product that microorganisms can be rapidly decompose in nature without any environmental pollution.This study aims to investigate the effects of E-beam and Co60-γ irradiation on the total saponins content in the crude extract of the S mukorossi. The S mukorossi powder is irradiated with E-beam and Co60-γ ray at doses of 0, 4, 6, 8, 10, and 12 kGy for E-beam and 0, 50, 100, 150, and 200 Gy, respectively, for Co60-γ ray. The changes in the content of total saponins in the crude extract, total detergency, and the bacteriostatic abilities before and after the irradiation were analyzed. The results showed that the content of total saponins in samples irradiated by E-beam was significantly higher than that in non-irradiated samples. The saponins yield was the highest at a radiation dose of 6 kGy, and the detergency and bacteriostatic ability were also the strongest. After low-dose Co6-γ irradiation, the total saponins in the S mukorossi crude extract, and detergency and bacteriostatic ability had no apparent change. Conclusion: E-beam irradiation at a dose of 6 kGy can effectively improve the content of total saponins in the crude extract of S mukorossi powder. In addition, its effects on detergency and bacteriostatic abilities are relatively significant. The findings provide sufficient reference data for the further development of S mukorossi commodities.

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Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200201 ◽

2020 ◽

Vol 92 (2) ◽

pp. 20402

Author(s):

Kaoutar Benthami ◽

Mai ME. Barakat ◽

Samir A. Nouh

Keyword(s):

Refractive Index ◽

Optical Properties ◽

Band Gap ◽

Color Difference ◽

Band Gap Energy ◽

Polybutylene Terephthalate ◽

Γ Irradiation ◽

Gap Energy ◽

Vis Spectroscopy ◽

Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

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Photolytic and thermal annealing of radical anions gamma-irradiated monocarboxylic acids

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19793632 ◽

1979 ◽

Vol 44 (12) ◽

pp. 3632-3643 ◽

Cited By ~ 7

Author(s):

Karel Mach ◽

Igor Janovský ◽

Karel Vacek

Keyword(s):

Thermal Annealing ◽

Pivalic Acid ◽

Esr Spectra ◽

Paramagnetic Species ◽

Radical Anions ◽

Γ Irradiation ◽

Before And After ◽

Optical Bleaching ◽

The Difference ◽

Gamma Irradiated

Total yields of paramagnetic species, their optical bleaching and thermal annealing in acetic, propionic, a-butyric, isobutyric, and pivalic acid γ-irradiated at 77 K were followed by ESR spectroscopy. Radical anions, always found after irradiation, disappear during optical bleaching without formation of any paramagnetic product. During thermal annealing they are converted almost quantitatively into the α-radicals of the respective acid, with the exception of pivalic acid. Amounts of radical anions were estimated from the difference of integrated ESR spectra taken before and after optical bleaching. The results show that approximately equal amounts of the reduction and oxidation paramagnetic products of the γ-irradiation can be detected.

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