Expanding phenomena over matrix rings Karabulut, Y. Demi̇roğlu; Koh, Doowon; Pham, Thang ...
Forum mathematicum,
07/2019, Letnik:
31, Številka:
4
Journal Article
Recenzirano
Odprti dostop
In this paper, we study expanding phenomena in the setting of matrix rings.
More precisely, we will prove that
We also obtain similar results for the cases of
and
, where
are sets in
Background
Dermatology literature lacks a study investigating both histopathological and dermatoscopic features of dermatofibroma.
Objective
To analyse histopathological, dermatoscopic and digital ...microscopic features of dermatofibromas.
Methods
Two hundred dermatofibromas and 190 patients were included and retrospectively evaluated. Nine histopathological and ten dermatoscopic patterns were used to classify the lesions. We identified four different types of dermatofibroma in digital microscopy.
Results
The mean age of the patients was 42.18 ± 13.72 years. Dermatofibroma was more common in females (67%) and the male to female ratio was 1 : 1.97. The most common location was leg (41%). The most frequent histopathological variant was fibrocollagenous type (49%). Grenz zone was the most common histopathological finding (89%). The most frequent digital microscopic type was type 1 (63%).
Conclusions
We found that palisading variant displayed only pattern 6 in dermatoscopy and cellular variant showed type 3 significantly in digital microscopy.
Magnesium orthosilicate (Mg2SiO4) was synthesized via a traditional solid-state reaction and a wet chemical route. This study primarily reported the thermoluminescence (TL) behavior of Mg2SiO4 host. ...X-ray diffraction pattern revealed that Mg2SiO4 exhibits orthorhombic structure matched with JCPDS card 900-6398. Dose response, reproducibility and trap parameters of TL glow curves were evaluated to clearly reveal TL features. Two TL glow peaks situated at 81 °C and 192 °C were monitored at a heating rate of 2 °Cs−1. We observed anomalous heating rate effect for the peak centered at 192 °C whilst TL intensity of the peak at 81 °C decreases with elevating heating rate. Trap depths of the electrons within the trap centers were found to be 1.04 ± 0.01eV and 1.37 ± 0.01eV for both methods using peak shape (PS) method. Distribution of trap centers was examined using the Tmax−Tstop method and this case indicated that the glow curves consist of single TL peaks. The intensity of TL glow curves exhibited a good linear dose response under total area up to 20 Gy. A comparison of the two preparation techniques revealed that TL characteristics of this phosphor are partly dependent and Mg2SiO4 could be a promising material for dosimetric application.
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•Mg2SiO4 phosphors synthesized by a solid-state reaction and wet chemical processes.•TL glow curve recorded under beta excitation.•TL glow curve contains dual peak at 81 °C and 193 °C.•Anomalous heating rate was observed.•Phosphor exhibits dosimetric TL glow peak.
BaMgAl10O17 (BAM) is a highly suitable host lattice for various rare earth ions with excellent luminescence properties in different spectral regions, including a strong photoluminescence (PL) ...emission from the visible spectral region. A new Ce- and Tb-incorporated BaMgAl10O17 phase was synthesized successfully using a wet combustion method and it was studied as a function of the temperature and laser excitation power. We further characterize the obtained phosphors with X-ray diffraction at room temperature. Different fuel/oxidant (f/o) ratios were introduced to investigate the optimum synthesis conditions for the BAM phosphors and optimum ratio was found out to be 8. The photoluminescence (PL) spectra were collected under the excitation light generated by a Nd:YLF pulse laser at 349 nm as the temperature was increased from 10 K to 300 K. A strong green emission of Tb3+ was observed in the green region of the spectrum due to the 5D4→7FJ transition. We also observed a wide emission band from the Ce3+ ion in the wavelength range of 350–650 nm. The luminescence intensities of all phosphors exhibited different patterns with an increase in the temperature. We also evaluated how the PL spectrum of the rare earth-activated BAM host matrix shifts under various laser excitation powers. The PL intensity of Ce-activated BAM significantly shifted (~30 A) to the blue region of the spectrum with an increase in the laser excitation power, however we did observed no shift forTb3+ activated BAM. The present findings suggest that Tb-incorporated BaMgAl10O17 can be effective as a green phosphor candidate material with a wide range of applications.
•BaMgAl10O17 (BAM) phosphors have been prepared via a gel combustion method.•The phosphors exhibit different emissions due to Ce3+ and Tb3+.•The effect of laser excitation power on luminescence properties was discussed.•Tb-incorporated BaMgAl10O17 can be effective as a green phosphor candidate material.
A series of MoO3:Dy3+ phosphors have been synthesized via the gel-combustion method. The X-ray and photoluminescence (PL) emission spectra were employed to characterize the obtained phosphors. The ...prepared samples were characterized through XRD measurements and exhibited that Dy3+ ions can be successfully incorporated into the host material. The PL emission bands of Dy3+ doped MoO3 were observed at 486 nm, 574 nm and 666 nm which are assigned to the transitions of 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 and 4F9/2 → 6H11/2, respectively. Concentration quenching were largely taken into consideration as one of the crucial aspects limiting the application range of phosphors in today's modern world. An abnormal thermal quenching dependence was reported when Dy3+ ions were incorporated into MoO3 host matrix. In order to understand the origin of this beneficial behaviour, energy transfer processes occurring via radiative and nonradiative mechanisms were investigated to elucidate this suppression of the concentration quenching.
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•MoO3 phosphors doped with Dy were synthesized by a gel-combustion method.•Photoluminescence of undoped, and Dy doped MoO3 phosphors are reported.•Concentration quenching was suppressed.
La2MoO6 orange-red phosphors with high efficiency incorporated with Eu, Dy and Sm have been synthesized through a gel combustion method. The influences of rare earth doping in synthesized samples ...were analysed by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and cathodoluminescence. Rare earth doped La2MoO6 samples show strong emission bands in the range of 400–750 nm and optimal doping concentration for all samples was 2 mol%. La2MoO6 host doped Eu ion showed intense and predominant emission peaks in 450–750 nm range. The electrical multipolar interaction contributed to the non-radiative energy transfer between Eu3+ ions in La2MoO6 host matrix. Sm doped La2MoO6 host exhibited orange-red CL emission peaks at 564, 608, 652 and 708 nm La2MoO6:Dy3+ phosphor displayed emissions at 484, 574 and 670 nm, respectively. The observed intense and sharp emission peaks indicate that La2MoO6 is promising host for lanthanides doped phosphor materials in the applications of optoelectronic.
•Eu3+, Sm3+ and Dy3+ activated La2MoO6 phosphors are synthesized by gel combustion method.•Optimal doping concentration for all samples was 2 mol%.•Cathodoluminescence properties of Eu3+, Sm3+ and Dy3+ activated La2MoO6 phosphors are discussed.
Laser powder bed fusion process is one of the most widely used Additive Manufacturing techniques for fabricating metal components, however the surface quality of such components still remains a ...challenge and fails to meet the user expectations. Thus, this study presents a systematic investigation on the effect of post‐processing operations including finish milling and drag finishing on the surface integrity and resulting mechanical properties of Inconel 718 specimens fabricated by laser powder bed fusion additive manufacturing technique. The influence of post‐processing operations on the surface and subsurface microstructure, microhardness and tensile strength on the Inconel 718 specimens are carefully examined and presented in this study. Finally, this work also contributes to understanding the critical wall (part) thickness that is notably induced from the post‐processing operations. It is revealed that the surface integrity and resulting mechanical properties of specimens significantly improved as compared to as‐built specimens once milling and drag finishing post‐processing are deployed. However, the degree of impact depends on the thickness of parts subjected to post‐processing.
In this study, the effect of post‐processing operations including milling and drag finishing on the surface integrity and resulting mechanical properties of Inconel 718 produced in various wall thicknesses by the laser powder bed fusion is investigated. After the post‐processing operations, the surface integrity and resulting mechanical properties of specimens significantly improved.
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