Physical and optical properties of the SLS glass doped with low Cr2O3 concentrations

AbstractThe aim of this work is to study the physical properties of Cr2O3 -doped soda lime silicate glass in batch of 25Na2O: 10CaO: (65-x)SiO2: xCr2O3 where 0.00 ≤ x ≤ 0.05 mol%. The glass samples were prepared by normal meltquenching technique with 1500°C melting-temperature. The amorphous structure of glass samples were confirmed by X-Ray Diffractrometer (XRD) analysis. The density of glass samples were increased with increasing of Cr2O3 concentration due to the higher molecular weight of Cr2O3 (Mw.=151.9904g/mol) than SiO2 (Mw.=60.0843g/mol). On the other hand, the molar volumes were decreased. It means that network of glasses were compressed because of the substitution of Cr2O3 in the place of SiO2. The refractive index of glass samples was increased. The optical spectra of glass samples were also investigated

Luminescence Property of Rare-Earth Doped Bismuth-Borate Glasses

AbstractWe fabricated rare-earth doped bismuth borate glasses by using melt-quench technique. Two different types glass samples of xBi2O3: (100-x)B2O3 (x=30 and 50) were made to compare the luminescence properties. We measured x-ray luminescence of Bi-glass by using a x-ray tube. Several dopants were doped into the Bi-glass to measure the x-ray luminescence such as CeO2, Nd2O3, Er2O3, Dy2O3, Pr2O3, Sm2O3, Ho2O3, Gd2O3 and CeF3. Among them, Dy2O3, Nd2O3 and Sm2O3 doped Bi-glass emitted luminescence. We measured emission spectrum of each samples. Dy2O3 doped bi-glass has emission band at 482nm, 575nm, 662nm and 765nm. Nd2O3 doped bi-glass have emission band at 895nm and Sm2O3 doped Bi-glass has emission band at 569nm, 598nm, 641nm and 705nm. Moreover, Bi-glass scintillators with high light yield with good radiation hardness and low cost can be applied in high energy and nuclear physics, medical imaging, homeland security and radiation detection

The Effect of Heat Treatment on Crystal Structure in Zircon Monitored by ESR and XRD

AbstractX-band ESR spectra of zircon before and after heat treatment under oxygen rich atmosphere were measured with directions of the magnetic field applied in parallel and perpendicular to c-axis [001]. Seven peaks of Zeeman interaction were generated from the microwave energy absorptions due to the transitions between the spin states of natural impurity, gadolinium ions (Gd3+, S = 7/2). Angular variation of peak positions reflects that the symmetry surrounding of Gd3+ is D2d, signifying the replacement of Zr4+ by Gd3+ in the lattice. From XRD patterns, the unheated and after heated zircon are the same phase i.e. tetragonal phase of the space group I41/amd. The Rietveld refinement method was employed for derivation of the bond distance and bond angles of zirconium, silicon and oxygen atoms

Irradiation effect on natural quartz from Zambia

AbstractThe effects of high gamma-irradiation doses (50-300 kGy) on natural quartz crystals have been investigated by ESR technique. The ESR spectrum carried out at low temperature (120K) displayed lines group of Al center. The higher amount of gamma doses affected ESR spectra by increasing of intensity, especially the increasing intensity in the range of the Al center. The complex ESR spectra of Al center observed to contain 9 peaks that did not reach saturation even though the level of gamma-irradiation dose was as high as 300 kGy. The total area under ESR spectra of Al center was increased as a polynomial function of irradiated dose. The overlapping of ESR signal from defects in the range of Al center was also investigated

Quantification of the antimalarial drug pyronaridine in whole blood using LC–MS/MS — increased sensitivity resulting from reduced non-specific binding

Malaria is one of the most important parasitic diseases of man. The development of drug resistance in malaria parasites is an inevitable consequence of their widespread and often unregulated use. There is an urgent need for new and effective drugs. Pyronaridine is a known antimalarial drug that has received renewed interest as a partner drug in artemisinin-based combination therapy. To study its pharmacokinetic properties, particularly in field settings, it is necessary to develop and validate a robust, highly sensitive and accurate bioanalytical method for drug measurements in biological samples. We have developed a sensitive quantification method that covers a wide range of clinically relevant concentrations (1.5 ng/mL to 882 ng/mL) using a relatively low volume sample of 100 μL of whole blood. Total run time is 5 min and precision is within ±15% at all concentration levels. Pyronaridine was extracted on a weak cation exchange solid-phase column (SPE) and separated on a HALO RP amide fused-core column using a gradient mobile phase of acetonitrile–ammonium formate and acetonitrile-methanol. Detection was performed using electrospray ionization and tandem mass spectrometry (positive ion mode with selected reaction monitoring). The developed method is suitable for implementation in high-throughput routine drug analysis, and was used to quantify pyronaridine accurately for up to 42 days after a single oral dose in a drug-drug interaction study in healthy volunteers

The influence of CeF₃ on radiation hardness and luminescence properties of Gd₂O₃–B₂O₃ glass scintillator

The effect of CeF3 concentration and γ-irradiation on the physical, optical and luminescence properties of Gd2O3–B2O3–CeF3 glasses were studied in this work. Before irradiation, the addition of CeF3 in glass degraded the network connectivity observed from FTIR and possibly created the non-bridging oxygen (NBO) in glass structure. This NBO caused the reduction of Ce3+/Ce4+ ratio in XANES, the red-shift in transmission spectra and the raise of refractive index with addition of CeF3 content. Such red-shift also was influenced by 4f–5d transition of Ce3+ dopant. This ion generated the strongest photoluminescence (PL) and radioluminescence (RL) in 0.3 mol% CeF3-doped glass with nanoseconds decay time. The irradiation with γ-rays damaged the glass structure, broke the chemical bonds, and created color center in the glass network. The non-bridging oxygen hole center (NBOHC), that absorbed photons in the visible light region, caused the darkening, color change and increment of refractive index. These irradiation effects on glass were mitigated by the addition of CeF3 that the electron donation of Ce3+ decreased the number of NBOHC. The Ce3+/Ce4+ ratio in most glasses after irradiation then reduced compared to them before irradiation, resulting to the decrease in PL and RL intensity. Our results confirm that CeF3 can enhance the radiation hardness of glass and the 0.3 mol% CeF3-doped glass is a promising glass scintillator.Kaewnuam E., Wantana N., Ruangtaweep Y., et al. The influence of CeF₃ on radiation hardness and luminescence properties of Gd₂O₃–B₂O₃ glass scintillator. Scientific Reports 12, 11059 (2022); https://doi.org/10.1038/s41598-022-14833-3

First Results from the AMoRE-Pilot neutrinoless double beta decay experiment

The Advanced Molybdenum-based Rare process Experiment (AMoRE) aims to search for neutrinoless double beta decay (0$\nu\beta\beta$) of $^{100}$Mo with $\sim$100 kg of $^{100}$Mo-enriched molybdenum embedded in cryogenic detectors with a dual heat and light readout. At the current, pilot stage of the AMoRE project we employ six calcium molybdate crystals with a total mass of 1.9 kg, produced from $^{48}$Ca-depleted calcium and $^{100}$Mo-enriched molybdenum ($^{48\textrm{depl}}$Ca$^{100}$MoO$_4$). The simultaneous detection of heat(phonon) and scintillation (photon) signals is realized with high resolution metallic magnetic calorimeter sensors that operate at milli-Kelvin temperatures. This stage of the project is carried out in the Yangyang underground laboratory at a depth of 700 m. We report first results from the AMoRE-Pilot $0\nu\beta\beta$ search with a 111 kg$\cdot$d live exposure of $^{48\textrm{depl}}$Ca$^{100}$MoO$_4$ crystals. No evidence for $0\nu\beta\beta$ decay of $^{100}$Mo is found, and a upper limit is set for the half-life of 0$\nu\beta\beta$ of $^{100}$Mo of $T^{0\nu}_{1/2} > 9.5\times10^{22}$ y at 90% C.L.. This limit corresponds to an effective Majorana neutrino mass limit in the range $\langle m_{\beta\beta}\rangle\le(1.2-2.1)$ eV

On stationary points of nonexpansive set-valued mappings

In this paper we deal with stationary points (also known as endpoints) of nonexpansive set-valued mappings and show that the existence of such points under certain conditions follows as a consequence of the existence of approximate stationary sequences. In particular we provide abstract extensions of well-known fixed point theorems.Dirección General de Enseñanza SuperiorJunta de Andalucí