This work describes the impact of trivalent samarium (Sm3+) ions concentrations on the thermal, structural, physical, optical and photoluminescence (PL) characteristics in Zinc Sodium Lead Borate ...(ZnNaPbB) glasses with configuration (70-x) B2O3–10PbO–10ZnO–10Na2CO3-xSm2O3, (where x = 0.1–2.0 mol%). The glass samples were synthesized using a traditional melt-quench technique and characterized by various spectroscopic methods such as X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared (FT-IR), UV–Vis–NIR spectra, Differential scanning calorimetry (DSC) and PL emission-excitation spectra to illuminate their photonic applications. The broad band perceived in the XRD diffractogram confirmed the amorphous nature of an un-doped ZnNaPbB glass. The physical properties including thickness, density, molar volume, dielectric constant, rare earth (RE) ion concentration, field strength and molecular electronic polarizability, etc. were calculated from the standard formulae. The FT-IR spectra identify the presence of stretching vibration in BO3 and BO4 units with some additional structural and functional groups with their bond nature. The observed DSC data was used to estimate the glass transition temperature (Tg). The absorption spectra presented all the probable transitions of Sm3+ ion-doped ZnNaPbB glass and the optical band gaps were computed using Tauc's method. All the glass samples depicted band gap values over 3 eV, proving that the material is insulating. The absorption spectra were utilized to evaluate Judd-Ofelt (J-O) parameters which were further used in different radiative parameters calculations to find the luminous levels of Sm3+ ions doped ZnNaPbB glasses. The PL emission spectra of the present ZnNaPbBSm glasses parade four bands parallel to the transitions 4G5/2 to 6H5/2 (563 nm), 6H7/2 (599 nm), 6H9/2 (646 nm) and 6H11/2 (706 nm), respectively. Additionally, the evaluated values of the emission cross-section and branching ratios describe the suitability of the present ZnNaPbBSm glasses for optoelectronic applications. Further, the colorimetric parameters such as CIE coordinates (x, y) and correlated color temperature (CCT) were evaluated using PL emission data and the measured CIE coordinates are found in the reddish-orange region for the present glasses. The time decay profiles of as-prepared glasses were used to evaluate the experimental lifetime, energy transfer parameter and type of donor-acceptor interaction. The Dexter theory and Inokuti-Hirayama (I–H) fitting are used to recognize the type of interaction in non-radiative energy transfer which is responsible for the concentration quenching. The result demonstrates that the as-prepared ZnNaPbBSm glasses are applicable for optoelectronics device applications.
•ZnNaPbB glasses doped with Sm3+ ions were prepared by melt quench method.•XRD recorded for ZnNaPbB glass reveals its amorphous nature.•The J-O parameters for all the as-prepared ZnNaPbBSm glasses possess an identical order (Ω2>Ω4>Ω6).•PL spectra reveal most intense transition at 599 nm and emit reddish-orange luminescence.•I–H model and Dexter theory reveal dipole-dipole type interaction responsible for quenching.
The structure of Ge20Sb x Se80–x (x = 5, 15, 20) glasses was investigated by neutron diffraction, X-ray diffraction, and extended X-ray fine structure measurements at the Ge, Sb, and Se K-edges. For ...each composition, large-scale structural models were obtained by fitting simultaneously the experimental data sets in the framework of the reverse Monte Carlo simulation technique. It was found that the structures of these glasses can be described mostly by the chemically ordered network model. Ge–Se and Sb–Se bonds are preferred; Se–Se bonds in the Se-poor composition (x = 20) and M–M (M = Ge, Sb) bonds in strongly Se-rich glass (x = 5) are not needed. The quality of the fits was significantly improved by introducing Ge–Ge bonding in the nearly stoichiometric composition (x = 15), showing a violation of chemical ordering. The structure of Ge20Sb x Se80–x was compared to that of several glasses from the three analogous systems (Ge–As–Se, Ge–As–Te, Ge–Sb–Te), and it was found that chemical short-range order becomes more pronounced upon substituting As with Sb and Se with Te. Ge–As–Se glasses behave as random covalent networks over a very broad composition range. Chemical short-range order and disorder coexist in both Te-rich and Te-poor Ge–As–Te glasses, whereas amorphous Ge14Sb29Te57 and Ge22Sb22Te56 are governed by strict chemical preferences.
Abstract
The experimental data for the nuclear fusion of
27
Al with
74
Ge are examined within the context of symmetric-asymmetric Gaussian barrier distribution (SAGBD) model in sub-barrier domain. ...For bombarding energies smaller than the Coulomb barrier, predictions owing to simple Wong formula are found to be much smaller with reference to experimental outcomes. On other side, the SAGBD method is used, wherein impacts of inherent channels as a result of its multidimensional aspect of quantum mechanical tunneling arises because of weighted Gaussian function, to get desired outcomes. Larger fusion enhancement appears at lower energy region, which signifies the effective participation of inherent channels originated due to structure of participants. In present approach, the impacts of various inherent channels are cumulatively determined by calculating values of channel couplings parameter (
λ
) &
V
CBRED
. Present calculations due to the SAGBD method suggests that the theoretical fusion excitation functions for
27
Al +
74
Ge reaction are in close resemblance with experimental findings around the nominal barrier.
Fusion dynamics of 12C + 46,48,50Ti reactions are examined by considering EDWSP and coupled channel (CC) formalism. The coupled channel outputs point out that there are significant contributions of ...the vibrational states of the Ti-isotopes and without taking into account of these states one cannot explain the behavior of the fusion outcomes of given reactions. The EDWSP based outputs govern barrier modifications and subsequently decreases effective fusion barrier between the participants. Because of it, EDWSP based computations consistently retrieve the fusion data of studied systems. Aforementioned models decently explored fusion behavior of given systems, which clearly reflects that barrier changing effects are appeared due to energy dependency in Woods-Saxon potential are quite similar to that of dominant channel couplings in CC approach.
Fusion excitation functions of stable odd-A targets 147,149Sm with 16O projectile are theoretically analyzed within view of the symmetric-asymmetric Gaussian barrier distribution (SAGBD) formalism. ...For the purposes of this study, we assumed that bombardment energies of the 16O + 147,149Sm reactions would be around nominal barrier. For these reactions, Wong based computations fails to retrace the fusion data whereas SAGBD predictions fairly retrace the fusion data in entire bombarding energy range. The evaluated values of channel coupling parameter (λ) and VCBRED from SAGBD outcomes are found larger for heavier (16O + 149Sm) over lighter (16O + 149Sm) system, which suggests that heavier system possess extra fusion enhancement in sub-barrier domain. Present theoretical investigation highlights the significant contributions of intrinsic channels that emerges due to structure of reacting nuclei and such effects are empirically included in SAGBD method.
Abstract
Fusion dynamics of
12
C +
46,48,50
Ti reactions are examined by considering EDWSP and coupled channel (CC) formalism. The coupled channel outputs point out that there are significant ...contributions of the vibrational states of the Ti-isotopes and without taking into account of these states one cannot explain the behavior of the fusion outcomes of given reactions. The EDWSP based outputs govern barrier modifications and subsequently decreases effective fusion barrier between the participants. Because of it, EDWSP based computations consistently retrieve the fusion data of studied systems. Aforementioned models decently explored fusion behavior of given systems, which clearly reflects that barrier changing effects are appeared due to energy dependency in Woods-Saxon potential are quite similar to that of dominant channel couplings in CC approach.
Abstract
Fusion excitation functions of stable odd-A targets
147,149
Sm with
16
O projectile are theoretically analyzed within view of the symmetric-asymmetric Gaussian barrier distribution (SAGBD) ...formalism. For the purposes of this study, we assumed that bombardment energies of the
16
O +
147,149
Sm reactions would be around nominal barrier. For these reactions, Wong based computations fails to retrace the fusion data whereas SAGBD predictions fairly retrace the fusion data in entire bombarding energy range. The evaluated values of channel coupling parameter (λ) and V
CBRED
from SAGBD outcomes are found larger for heavier (
16
O +
149
Sm) over lighter (
16
O +
149
Sm) system, which suggests that heavier system possess extra fusion enhancement in sub-barrier domain. Present theoretical investigation highlights the significant contributions of intrinsic channels that emerges due to structure of reacting nuclei and such effects are empirically included in SAGBD method.
The experimental data for the nuclear fusion of 27Al with 74Ge are examined within the context of symmetric-asymmetric Gaussian barrier distribution (SAGBD) model in sub-barrier domain. For ...bombarding energies smaller than the Coulomb barrier, predictions owing to simple Wong formula are found to be much smaller with reference to experimental outcomes. On other side, the SAGBD method is used, wherein impacts of inherent channels as a result of its multidimensional aspect of quantum mechanical tunneling arises because of weighted Gaussian function, to get desired outcomes. Larger fusion enhancement appears at lower energy region, which signifies the effective participation of inherent channels originated due to structure of participants. In present approach, the impacts of various inherent channels are cumulatively determined by calculating values of channel couplings parameter (λ) & VCBRED. Present calculations due to the SAGBD method suggests that the theoretical fusion excitation functions for 27Al + 74Ge reaction are in close resemblance with experimental findings around the nominal barrier.
We assessed the potential of magnetic resonance urography (MRU) in the evaluation of hydronephrosis not explained by standard investigation in patients at high risk for upper tract urothelial cancer.
...A total of 23 consecutive patients in a specialist urological unit with unexplained hydronephrosis prospectively underwent MRU which comprised overview heavily T2-weighted MR urographic images followed by focused high resolution turbo spin echo T2-weighted sequences obtained in an axial and coronal oblique plane through the level of urinary obstruction. All were at high risk for urothelial cancer and had either contraindications to or problems with standard investigations including poor contrast excretion due to obstruction or renal failure, failed ureteral cannulation or contrast allergy. Clinical events and imaging followup, subsequent endoscopic/surgical findings and histopathology validated MR findings.
In 23 patients with a high clinical suspicion of upper tract transitional cell tumors (TCC), 8 ureteral and 5 renal pelvic TCCs (2 bilateral) were diagnosed by MR, and confirmed histologically. In a further 5 patients benign causes for the hydronephrosis were found. No intrinsic or extrinsic pathology was demonstrable in 5 patients whose imaging findings were stable during 1 year of followup.
MRU is a valuable noninvasive investigation for evaluating hydronephrosis in this group of patients with suspected urothelial cancer in which routine investigation had failed to provide clinically important information. Focused high resolution T2-weighted images were reliable in the diagnosis of ureteral and renal pelvic TCCs, and were valuable in excluding these and other mass lesions as the cause of hydronephrosis.
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