quenching method
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2022 ◽  
Vol 14 (2) ◽  
pp. 937
Author(s):  
Thair Hussein Khazaalah ◽  
Iskandar Shahrim Mustafa ◽  
M. I. Sayyed ◽  
Azhar Abdul Rahman ◽  
Mohd Hafiz Mohd Zaid ◽  
...  

In the current study, BaO was doped in Bi2O3-ZnO-B2O3-SLS glass to develop lead-free radiation shielding glasses and to solve the dark brown of bismuth glass. The melt-quenching method was utilized to fabricate (x) BaO (1 − x)[0.3 ZnO 0.2 Bi2O3 0.2 B2O3 0.3 SLS] (where x are 0.01, 0.02, 0.03, 0.04, and 0.05 mol) at 1200 °C. Soda lime silica glass waste (SLS), which is mostly composed of 74.1% SiO2, was used to obtain SiO2. The mass attenuation coefficient (μm) was investigated utilizing X-ray fluorescence (XRF) at 16.61, 17.74, 21.17, and 25.27 keV and narrow beam geometry at 59.54, 662, and 1333 keV. Moreover, the other parameters related to gamma ray shielding properties such as half-value layer (HVL), mean free path (MFP), and effective atomic number (Zeff) were computed depending on μm values. The results indicated that HVL and MFP decreased, whereas μm increased with an increase in BaO concentration. According to these results, it can be concluded that BaO doped in Bi2O3-ZnO-B2O3-SLS glass is a nontoxic, transparent to visible light, and a good shielding material against radiation.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Hideki Hashimoto ◽  
Yohei Onodera ◽  
Shuta Tahara ◽  
Shinji Kohara ◽  
Koji Yazawa ◽  
...  

AbstractThe fabrication of novel oxide glass is a challenging topic in glass science. Alumina (Al2O3) glass cannot be fabricated by a conventional melt–quenching method, since Al2O3 is not a glass former. We found that amorphous Al2O3 synthesized by the electrochemical anodization of aluminum metal shows a glass transition. The neutron diffraction pattern of the glass exhibits an extremely sharp diffraction peak owing to the significantly dense packing of oxygen atoms. Structural modeling based on X-ray/neutron diffraction and NMR data suggests that the average Al–O coordination number is 4.66 and confirms the formation of OAl3 triclusters associated with the large contribution of edge-sharing Al–O polyhedra. The formation of edge-sharing AlO5 and AlO6 polyhedra is completely outside of the corner-sharing tetrahedra motif in Zachariasen’s conventional glass formation concept. We show that the electrochemical anodization method leads to a new path for fabricating novel single-component oxide glasses.


Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 343
Author(s):  
Huihui Song ◽  
Yuhu Hu ◽  
Jiale Zhang ◽  
Jinyu Fang ◽  
Xueling Hou

The melt-spun ribbons of LaFe11.5Si1.5Cx (x = 0, 0.1, 0.2, 0.3) compounds are prepared by the melt fast-quenching method. The doping of C is beneficial to the nucleation and precipitation of the La (Fe, Si)13 phase, which is indicated by the microstructure observation and the elemental analysis. Subsequently, the ribbons of LaFe11.5Si1.5C0.2 are annealed at different times, and the phase composition, the microstructures, and the magnetic properties are investigated. The LaFe11.5Si1.5C0.2 ribbons annealed at 1273 K for 2 h achieved the best magnetic properties, and the maximum isothermal magnetic entropy change with a value of 9.45 J/(kg·K) upon an applied field of 1.5 T at an increased Curie temperature 255 K.


Author(s):  
S. L. Meena

Abstract: Zinc lithium lead calcium borophosphate glasses containing Er3+ in (40- x):P2O5:10ZnO:10Li2O:10PbO:10CaO:20B2O3:xEr2O3 (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. The amorphous nature of the glasses was confirmed by x-ray diffraction studies. Optical absorption, Excitation, fluorescence and Transmittance spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross–section of various emission lines have been evaluated. Keywords: ZLLCBP Glasses, Optical Properties, Judd-OfeltTheory, Transmittance Properties.


Optik ◽  
2021 ◽  
Vol 247 ◽  
pp. 168014
Author(s):  
Chu Fenghong ◽  
Feng Shi ◽  
Bian Zhenglan ◽  
Zhao Chunpeng ◽  
Xue Liang ◽  
...  

2021 ◽  
Author(s):  
A. Amat ◽  
M. K. Halimah ◽  
M. Ishak ◽  
S. N. Nazrin ◽  
N. N. Syamimi ◽  
...  

Abstract [(TeO2)0.7(B2O3)0.3]1-x (BaO)x, x = 0.00, 0.05, 0.10, 0.20, 0.25, 0.30 and 0.35 mol fraction glass series were successfully synthesized by conventional melt quenching method. Amorphous phase of all samples was confirmed through X-ray diffraction while optical properties were determined using UV-VIS spectrophotometer. Fourier Transform Infrared (FTIR) analysis showed that the glass structure consisted of TeO3, TeO4, TeO6, BO3 and BO4 structural units. The optical band gap energy, Eopt which was calculated from Tauc’ plots decreased as the amount of BaO increases, whereas, the Urbach energy value increased. The increase in Urbach energy value was attributed to the increase of defects in glass structure. The refractive indices of glass were found to increase along with the increased amount of BaO, due to the high polarization and high density of host material and glass modifier. The molar polarizability, αm, oxide ion polarizability, αo2- and optical basicity, Λ of the glasses are calculated by Lorentz-Lorenz equation. The glasses were found to possess αm values between 8.106 – 8.489 Å3, and αo2- values between 3.303 to 4.772. Meanwhile, optical basicity increases from 0.115 to 0.893.


Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6901
Author(s):  
Rajesh Dagupati ◽  
Robert Klement ◽  
Ramaraghavulu Rajavaram ◽  
José J. Velázquez ◽  
Dušan Galusek

Transparent oxyfluoride glass-ceramics (GCs) with embedded β-Na1.5Y1.5F6 crystals doped with Er3+ ions were fabricated by a melt-quenching method with subsequent heat-treatment. The structural characterizations and spectroscopic techniques were performed to verify the precipitation of β-Na1.5Y1.5F6 crystals and partition of the Er3+ dopant into the crystals. Bright green up-conversion (UC) emission was achieved in Er3+-doped glass-ceramic (Er-GC). Furthermore, the temperature-dependent visible UC behavior based on thermally coupled energy levels (TCLs) and non-thermally coupled energy levels (NTCLs) was also examined in the temperature range 298 k to 823 K with maximum relative sensitivity (Sr) of 1.1% K−1 at 298 K for TCLs in Er-G and Er-GC samples.


2021 ◽  
Vol 2070 (1) ◽  
pp. 012050
Author(s):  
G Chandrashekaraiah ◽  
V C Veeranna Gowda ◽  
A Jayasheelan ◽  
C Narayana Reddy ◽  
K J Mallikarjunaiah

Abstract A borate glasses doped with rare earth Gd3+ ion in the system [6OB2O3 + 30 L12O + x Gd2O3 + (10-x) BiCl3] is prepared by the conventional melt quenching method and their optical properties have been studied. The oxide ion polarizability parameter is calculating by using refractive index of glass materials, which is obtained from UV-Vis spectra. The borate glasses are known to possess high oxide ion polarizability, high refractive index, high basicity and low interaction parameter values. In this present study, theoretical calculation of basicity and interaction parameter, using oxide ion polarization, of the glass network has been addressed. A good linear correlation between the interaction parameter and basicity is observed.


2021 ◽  
Vol 2076 (1) ◽  
pp. 012048
Author(s):  
Ning Zhang ◽  
Shiqing Man

Abstract The transition metal Mn2+ ions doped materials have been widely reported for the luminescent properties for its broad emission band from green to red due to the spin-forbidden 4T1→6A1 transitions. To investigate the luminescent properties of Mn2+ ions in cuspidine glass, the 3CaO-CaF2-2SiO2 glasses doped with different Mn2+ concentration were prepared with traditional melt-quenching method. The luminescence emission spectra, excitation spectra and luminescence decay curves were recorded and analyzed. The tunable broadband emission from orange to red was obtained. The luminescence intensity and lifetime of Mn2+: 4T1 level showed different quenching points with the increasing of Mn2+ concentration. All these results indicate that Mn2+ doped 3CaO-CaF2-2SiO2 glass could be applied as light conversion material for solid-state lighting applications.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hong-Hsiang Guan ◽  
Yen-Hua Huang ◽  
En-Shyh Lin ◽  
Chun-Jung Chen ◽  
Cheng-Yang Huang

Dihydroorotase (DHOase) possesses a binuclear metal center in which two Zn ions are bridged by a posttranslationally carbamylated lysine. DHOase catalyzes the reversible cyclization of N-carbamoyl aspartate (CA-asp) to dihydroorotate (DHO) in the third step of the pathway for the biosynthesis of pyrimidine nucleotides and is an attractive target for potential anticancer and antimalarial chemotherapy. Crystal structures of ligand-bound DHOase show that the flexible loop extends toward the active site when CA-asp is bound (loop-in mode) or moves away from the active site, facilitating the product DHO release (loop-out mode). DHOase binds the product-like inhibitor 5-fluoroorotate (5-FOA) in a similar mode to DHO. In the present study, we report the crystal structure of DHOase from Saccharomyces cerevisiae (ScDHOase) complexed with 5-FOA at 2.5 Å resolution (PDB entry 7CA0). ScDHOase shares structural similarity with Escherichia coli DHOase (EcDHOase). However, our complexed structure revealed that ScDHOase bound 5-FOA differently from EcDHOase. 5-FOA ligated the Zn atoms in the active site of ScDHOase. In addition, 5-FOA bound to ScDHOase through the loop-in mode. We also characterized the binding of 5-FOA to ScDHOase by using the site-directed mutagenesis and fluorescence quenching method. Based on these lines of molecular evidence, we discussed whether these different binding modes are species- or crystallography-dependent.


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