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24 pages, 2830 KiB  
Article
Nutritional, Phytochemical, and Biological Characterization of Peel, Pulp, and Seed Powder from the Fruits of Berberis mikuna and Berberis burruyacuensis: Potential as a Functional Ingredient
by Enzo Agustín Matteucci, María Eugenia Orqueda, Mariana Leal, María Inés Isla, Mario Simirgiotis, Iris Catiana Zampini, Oscar R. Dantur and María Alejandra Moreno
Plants 2025, 14(10), 1418; https://doi.org/10.3390/plants14101418 - 9 May 2025
Viewed by 584
Abstract
Berberis mikuna Job. (common name “mikuna”) and Berberis burruyacuensis O.R. Dantur, S. Radice, E. Giordani and Papini (common name “sacha mikuna”) are endemic native plant species from northwestern Argentina. The aim of this work was to evaluate, for the first time, the potential [...] Read more.
Berberis mikuna Job. (common name “mikuna”) and Berberis burruyacuensis O.R. Dantur, S. Radice, E. Giordani and Papini (common name “sacha mikuna”) are endemic native plant species from northwestern Argentina. The aim of this work was to evaluate, for the first time, the potential of the pulp, seed, and peel powders from B. mikuna and B. burruyacuensis fruits as functional food ingredients, with the purpose of adding value to these native resources and promoting their sustainable use. All powders exhibited nutritional value due to their protein, lipid, fiber, and ash content, especially the seed powder. Phenolic compounds (including xanthone, phenolic esters, coumarins, flavonoids, tannins, and anthocyanins), alkaloids, amino acids, lipids, and vitamins, totaling 33 compounds, were identified in the pulp, seed, and peel of both Berberis fruits through UHPLC-PDA-ESI-QT-MS/MS. High anthocyanin content was observed in the pulp and peel, mainly in B. mikuna (195.55 ± 7.75 and 283.49 ± 6.55 g C3GE/100 g of powder, respectively), while tannins were abundant in the seeds (3.64 ± 0.11 and 6.09 ± 0.06 mg PB2/100 g of powder for B. mikuna and B. burruyacuensis, respectively). The powders exhibited antioxidant activity (ABTS•+; H2O2) and the capacity to inhibit enzymes related to metabolic syndrome, such as α-glucosidase, α-amylase, and lipase. These findings suggest the potential of B. mikuna and B. burruyacuensis fruit powders as functional food ingredients, dietary supplements, or natural functional colorants for foods and beverages. Full article
(This article belongs to the Section Phytochemistry)
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14 pages, 13945 KiB  
Article
S-Bend and Y Waveguide Architectures in Germanate Glasses Irradiated by Femtosecond Laser
by Thiago Vecchi Fernandes, Camila Dias da Silva Bordon, Niklaus Ursus Wetter, Wagner de Rossi and Luciana Reyes Pires Kassab
Micromachines 2025, 16(2), 171; https://doi.org/10.3390/mi16020171 - 31 Jan 2025
Cited by 1 | Viewed by 1030
Abstract
This study is focused on the fabrication and characterization of various dual waveguides through femtosecond (fs) laser irradiation of GeO2-based glass samples. The objective of the present work is to develop diverse waveguide configurations, namely straight, S-bend and Y-shaped waveguides within [...] Read more.
This study is focused on the fabrication and characterization of various dual waveguides through femtosecond (fs) laser irradiation of GeO2-based glass samples. The objective of the present work is to develop diverse waveguide configurations, namely straight, S-bend and Y-shaped waveguides within GeO2–PbO glasses embedded with silver nanoparticles, utilizing a double-guide platform, for photonic applications such as resonant rings and beam splitters. Enhanced guidance was observed with a larger radius of curvature (80 mm) among the two distinct S-bend waveguides produced. The maximum relative propagation loss was recorded for the S-bend waveguide with a 40 mm radius, while the minimum loss was noted for the Y-shaped waveguide. In the latter configuration, with an opening angle of 5° and a separation of 300 µm between the two arms, an output power ratio of 50.5/49.5 between the left and right arms indicated promising potential for beam splitter applications. During the study, the quality factor (M2) of the proposed architectures was measured and the 80 mm S-bend configuration presented the best symmetry between the x and y axes; in the case of the Y configuration the similarity between the M2 values in both axes, for the first and second arms, indicates comparable light guidance. Full article
(This article belongs to the Special Issue Laser Micro/Nano Fabrication, Second Edition)
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30 pages, 13193 KiB  
Article
Revisiting the Concealed Zn-Pb±(Ag,Ge) VMS-Style Ore Deposit, Molai, Southeastern Peloponnese, Greece
by Elias Kevrekidis, Stavros Savvas Triantafyllidis, Stylianos Fotios Tombros, Sotirios Kokkalas, Joan Papavasiliou, Konstantinos Kappis, Konstantinos Papageorgiou, Ioannis Koukouvelas, Michalis Fitros, Dimitrios Zouzias, Panagiotis Voudouris, Degao Zhai and Karen St Seymour
Minerals 2024, 14(9), 885; https://doi.org/10.3390/min14090885 - 30 Aug 2024
Viewed by 2416
Abstract
The concealed Molai Zn-Pb±(Ag,Ge) stratiform deposit in southeastern Peloponnese is hosted in Triassic intermediate tuffs, ignimbrites and subaerial andesitic flows. The host rocks display trace element signatures of a Supra-Subduction Zone (SSZ) setting. Three ore-forming stages are recognized, with stages I and II [...] Read more.
The concealed Molai Zn-Pb±(Ag,Ge) stratiform deposit in southeastern Peloponnese is hosted in Triassic intermediate tuffs, ignimbrites and subaerial andesitic flows. The host rocks display trace element signatures of a Supra-Subduction Zone (SSZ) setting. Three ore-forming stages are recognized, with stages I and II related to formation of the epigenetic, stratiform, massive-to-semi-massive ore and a late stage III associated with vein-type mineralization. The O and D isotope geochemistry of gangue chlorite and epidote reveal mixing with fresh meteoric water during the weaning stages of the hydrothermal activity of the late stage II due to uplifting of the hydrothermal system. Sphalerite is the major ore phase, with three different varieties formed during stages I (Sp-I) and II (Sp-II and Sp-III). All sphalerite varieties coexist, depicting gradual change in the chemistry of the ore-forming fluids. Molai ores are characterized by elevated Ag and Ge contents. Tetrahedrite is the major Ag carrier, while among the three sphalerite varieties, early Sp-I comprises the highest Ge contents. The Molai Zn-Pb±(Ag,Ge) deposit is characterized by intermediate features between bimodal felsic massive sulfides and subaerial epithermal systems based on the shallow formation depth, the presence of hydraulic breccias associated with phase separation, the ore formation along high-angle faults, the relatively low ore-forming temperatures below 250 °C obtained from geothermometry, and the absence of the typical structure of bimodal felsic type ores. Full article
(This article belongs to the Special Issue Mineralization and Geochemistry of VMS Deposits)
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16 pages, 1934 KiB  
Article
Nickel Ions Activated PbO–GeO2 Glasses for the Application of Electrolytes and Photonic Devices
by L. Vijayalakshmi, Shaik Meera Saheb, R. Vijay, Kishor Palle, P. Ramesh Babu, Seong-Jin Kwon and G. Naga Raju
Inorganics 2024, 12(8), 215; https://doi.org/10.3390/inorganics12080215 - 8 Aug 2024
Viewed by 1298
Abstract
In this study, PbO–GeO2 glasses were melt-quenched at different nickel oxide concentrations. XRD and DSC techniques were characterized whether the samples are glass or crystalline materials. IR, Raman, and optical absorption techniques are used to obtain structural details. The IR spectra have [...] Read more.
In this study, PbO–GeO2 glasses were melt-quenched at different nickel oxide concentrations. XRD and DSC techniques were characterized whether the samples are glass or crystalline materials. IR, Raman, and optical absorption techniques are used to obtain structural details. The IR spectra have revealed that the glass network contained conventional structural units GeO4 and GeO6. The Ni2+ ion octahedral transition exhibited luminescence spectra in the region of 1200–1500 nm; it is due to 3T2 (3F) → 3A2(3F) transition. The glasses containing the highest concentration of NiO have been found to have high values of luminescence efficiency and the cross-section. The dielectric characteristics, such as the dielectric constant, loss, and a.c. conductivity (σac), were analyzed across extensive frequency and temperature ranges, with a specific emphasis on the nickel oxide concentration. Analyzing optical absorption and dielectric properties of the samples, it has been found that nickel ions’ majority occur in tetrahedral sites. It is proved that the dielectric constant and loss values are highest for the sample N10 and ac conductivity due to dipoles being lowest for the sample N10. It is revealed that the glasses are highly conducting due to the modifying action of Ni2+ ions so these glasses are suitable for solid electrolyte uses besides their optical applications in NLO devices. Full article
(This article belongs to the Special Issue Recent Research and Application of Amorphous Materials)
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31 pages, 4894 KiB  
Review
Advancements and Prospects in Perovskite Solar Cells: From Hybrid to All-Inorganic Materials
by Fernando Velcic Maziviero, Dulce M. A. Melo, Rodolfo L. B. A. Medeiros, Ângelo A. S. Oliveira, Heloísa P. Macedo, Renata M. Braga and Edisson Morgado
Nanomaterials 2024, 14(4), 332; https://doi.org/10.3390/nano14040332 - 8 Feb 2024
Cited by 21 | Viewed by 6250
Abstract
Hybrid perovskites, materials composed of metals and organic substances in their structure, have emerged as potential materials for the new generation of photovoltaic cells due to a unique combination of optical, excitonic and electrical properties. Inspired by sensitization techniques on TiO2 substrates [...] Read more.
Hybrid perovskites, materials composed of metals and organic substances in their structure, have emerged as potential materials for the new generation of photovoltaic cells due to a unique combination of optical, excitonic and electrical properties. Inspired by sensitization techniques on TiO2 substrates (DSSC), CH3NH3PbBr3 and CH3NH3PbI3 perovskites were studied as a light-absorbing layer as well as an electron–hole pair generator. Photovoltaic cells based on per-ovskites have electron and hole transport layers (ETL and HTL, respectively), separated by an ac-tive layer composed of perovskite itself. Major advances subsequently came in the preparation methods of these devices and the development of different architectures, which resulted in an efficiency exceeding 23% in less than 10 years. Problems with stability are the main barrier to the large-scale production of hybrid perovskites. Partially or fully inorganic perovskites appear promising to circumvent the instability problem, among which the black perovskite phase CsPbI3 (α-CsPbI3) can be highlighted. In more advanced studies, a partial or total substitution of Pb by Ge, Sn, Sb, Bi, Cu or Ti is proposed to mitigate potential toxicity problems and maintain device efficiency. Full article
(This article belongs to the Topic Thin-Film Photovoltaics: Constituents and Devices)
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14 pages, 3300 KiB  
Article
Tunable Visible Light and Energy Transfer Mechanism in Tm3+ and Silver Nanoclusters within Co-Doped GeO2-PbO Glasses
by Marcos Vinicius de Morais Nishimura, Augusto Anselmo Amaro, Camila Dias da Silva Bordon, Jessica Dipold, Niklaus Ursus Wetter and Luciana Reyes Pires Kassab
Micromachines 2023, 14(11), 2078; https://doi.org/10.3390/mi14112078 - 9 Nov 2023
Cited by 1 | Viewed by 1752
Abstract
This study introduces a novel method for producing Ag nanoclusters (NCs) within GeO2-PbO glasses doped with Tm3+ ions. Sample preparation involved the melt-quenching method, employing adequate heat treatment to facilitate Ag NC formation. Absorption spectroscopy confirmed trivalent rare-earth ion incorporation. [...] Read more.
This study introduces a novel method for producing Ag nanoclusters (NCs) within GeO2-PbO glasses doped with Tm3+ ions. Sample preparation involved the melt-quenching method, employing adequate heat treatment to facilitate Ag NC formation. Absorption spectroscopy confirmed trivalent rare-earth ion incorporation. Ag NC identification and the amorphous structure were observed using transmission electron microscopy. A tunable visible emission from blue to the yellow region was observed. The energy transfer mechanism from Ag NCs to Tm3+ ions was demonstrated by enhanced 800 nm emission under 380 and 400 nm excitations, mainly for samples with a higher concentration of Ag NCs; moreover, the long lifetime decrease of Ag NCs at 600 nm (excited at 380 and 400 nm) and the lifetime increase of Tm3+ ions at 800 nm (excitation of 405 nm) corroborated the energy transfer between those species. Therefore, we attribute this energy transfer mechanism to the decay processes from S1→T1 and T1→S0 levels of Ag NCs to the 3H4 level of Tm3+ ions serving as the primary path of energy transfer in this system. GeO2-PbO glasses demonstrated potential as materials to host Ag NCs with applications for photonics as solar cell coatings, wideband light sources, and continuous-wave tunable lasers in the visible spectrum, among others. Full article
(This article belongs to the Special Issue Nanomaterials Photonics)
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21 pages, 7286 KiB  
Article
Sphalerite and Pyrite Geochemistry from the Pusangguo Co-Rich Cu–Zn–Pb Skarn Deposit, Tibet: Implications for Element Occurrence and Mineralization
by Zhuang Li, Hao Tan, Feng Zhao, Zuopeng Xiang, Han Wu and Peng Zhang
Minerals 2023, 13(9), 1165; https://doi.org/10.3390/min13091165 - 1 Sep 2023
Cited by 1 | Viewed by 2882
Abstract
The Pusangguo deposit (1.42 Mt @ 1.42% Cu, 0.14 Mt @ 1.82% Zn, 0.08 Mt @ 1.01% Pb, and 285.8 t Co @ 140 g/t Co) is the first Co-rich Cu-Zn-Pb skarn deposit discovered in the Gangdese metallogenic belt. However, the trace and [...] Read more.
The Pusangguo deposit (1.42 Mt @ 1.42% Cu, 0.14 Mt @ 1.82% Zn, 0.08 Mt @ 1.01% Pb, and 285.8 t Co @ 140 g/t Co) is the first Co-rich Cu-Zn-Pb skarn deposit discovered in the Gangdese metallogenic belt. However, the trace and minor element geochemistry of the sulfides in this deposit has not been studied, limiting further understanding of elements’ occurrence and mineralization. Here, we identified four ore stages, and two types of sphalerites (SpI and SpII) and pyrites (PyI and PyII), in this deposit. In this study, LA-ICP-MS in-situ trace element analyses were conducted on sphalerite and pyrite, to obtain their chemical compositions, elemental substitution mechanisms, and mineralization physicochemical conditions. The results indicate that two types of sphalerites are generally more enriched with Co than pyrite. SpI has higher concentrations of Co, Cr, Cu, Ag, and As compared to SpII. Both types of sphalerite have very low contents of Sn, Ge, and Ga. PyII has higher contents of most trace elements, such as Co, Ni, Mn, Zn, Cu, As, Sn, Se, Pb, Ag, and Bi, compared to PyI. Both types of pyrite are poor in Mn, Ga, Ge, and Cd, but enriched in As, Co, and Ni. The Mn, Fe, Co, and Cd in sphalerite, and Co, Ni, and Mn in pyrite are generally lattice-bound, while Cu, As, Ag, and Sb are usually present in both micro-inclusions and coupled substitution. Significant elemental correlations in sphalerite indicate the possible substitution mechanisms 2Fe2+ + Ga2+ ↔ 3Zn2+, 2Fe2+ + Ge4+ ↔ 4Zn2+, and (Sb3+, Sn3+) + (Cu+, Ag+) ↔ 2Zn2+. The correlation trends between trace elements in pyrite suggest the coupled substitution mechanisms of (Tl+ + Cu+ + Ag+) + (As3+ + Sb3+) ↔ 2Zn2+ and As3+ + Cu+ ↔ 2Zn2+. The mineralization temperature at Pusangguo, as determined by the GGIMFis sphalerite geothermometer, is 237–345 °C (avg. 307 °C), consistent with the high Zn/Cd ratio (avg. 203), low Ga/In (avg. 0.06), and high In/Ge (avg. 15.9) in sphalerite, and high Co/Ni ratio (avg. 24) in pyrite. These results indicate that the ore-forming fluid was high-temperature, with a low sulfur fugacity (fS2) (10−13.4 to 10−8.3) and low oxygen fugacity (fO2). The high temperature, and low sulfur fugacity and oxygen fugacity of the ore-forming fluid, and the fluid-mixing process, jointly controlled the sulfide precipitation, which caused the formation of the Pusangguo deposit. Full article
(This article belongs to the Special Issue Sulfide Mineralogy and Geochemistry)
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9 pages, 1446 KiB  
Article
A Study of PbF2 Nanoparticles Crystallization Mechanism in Mixed Oxyde-Fluoride Glasses
by Saule Dyussembekova, Ekaterina Trusova, Sergey Kichanov, Kiril Podbolotov and Denis Kozlenko
Ceramics 2023, 6(3), 1508-1516; https://doi.org/10.3390/ceramics6030093 - 11 Jul 2023
Cited by 2 | Viewed by 1660
Abstract
Samples of nanocrystalline PbF2 glass ceramics were obtained by heat-treating SiO2–GeO2–PbO–PbF2–CdF2 glasses. The Ho2O3 and Tm2O3 doping effects on the structural features of PbF2 nanoparticles were studied using [...] Read more.
Samples of nanocrystalline PbF2 glass ceramics were obtained by heat-treating SiO2–GeO2–PbO–PbF2–CdF2 glasses. The Ho2O3 and Tm2O3 doping effects on the structural features of PbF2 nanoparticles were studied using small-angle X-ray scattering and X-ray diffraction methods. The enlargements of the average sizes of nanoparticles and the sizes of local areas of density fluctuations have been found to be correlated with an increase in concentrations of Ho2O3 and Tm2O3 in initial glasses. A variation in the concentrations of Ho2O3 and Tm2O3 does not affect the morphology and fractal dimension of the formed PbF2 nanoparticles. Full article
(This article belongs to the Special Issue Advanced Glasses and Glass-Ceramics)
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11 pages, 934 KiB  
Article
Highly Luminescent Rb-Doped Cs4PbBr6 Nanocrystals in Borogermanate Glass
by Damir Valiev, Rufina Kharisova, Anastasiia Babkina, Ksenia Zyryanova, Natalia Kuzmenko, Yevgeniy Sgibnev, Artem Shelaev and Alexander V. Baryshev
Photonics 2023, 10(7), 729; https://doi.org/10.3390/photonics10070729 - 26 Jun 2023
Cited by 3 | Viewed by 1795
Abstract
For the first time, the synthesis, luminescent and structural properties of stable perovskite-type (Cs1−xRbx)4PbBr6 (R = Cs, Rb) nanocrystals are shown. In the absence of rubidium, Cs4PbBr6 and CsPbBr3 perovskite crystals precipitate [...] Read more.
For the first time, the synthesis, luminescent and structural properties of stable perovskite-type (Cs1−xRbx)4PbBr6 (R = Cs, Rb) nanocrystals are shown. In the absence of rubidium, Cs4PbBr6 and CsPbBr3 perovskite crystals precipitate in the ZnO–Na2O–B2O3–GeO2 glass matrix. With ascending rubidium content, the precipitation of (Cs,Rb)4PbBr6 nanocrystals is replaced by the Rb4PbBr6 nanocrystals nucleation. Nucleated nanocrystals exhibit an intense green luminescence. With an increase of the rubidium content, the luminescence maximum shifts to the blue region, the luminescence quantum yield increases from 28 to 51%, and the average decay time increases from 2 to 8 ns. Several assumptions have been made about the nature of the green luminescence of perovskite-like Cs4PbBr6 and (Cs,Rb)4PbBr6 crystals in glasses. It is concluded that the most probable cause is the impurity inclusions of CsPbBr3 and (Cs,Rb)PbBr3 crystals. Full article
(This article belongs to the Special Issue Women’s Special Issue Series: Photonics)
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11 pages, 2232 KiB  
Article
Germanium Complexes with ONO Tridentate Ligands: O-H Bond Activation Control According to DFT Calculations
by Kirill V. Zaitsev, Andrey D. Trubachev and Oleg Kh. Poleshchuk
Int. J. Mol. Sci. 2023, 24(12), 10218; https://doi.org/10.3390/ijms241210218 - 16 Jun 2023
Cited by 3 | Viewed by 1871
Abstract
Polydentate ligands are used for thermodynamic stabilization of tetrylenes—low-valent derivatives of Group 14 elements (E = Si, Ge, Sn, Pb). This work shows by DFT calculations how the structure (the presence or absence of substituents) and type (alcoholic, Alk, or phenolic, Ar) of [...] Read more.
Polydentate ligands are used for thermodynamic stabilization of tetrylenes—low-valent derivatives of Group 14 elements (E = Si, Ge, Sn, Pb). This work shows by DFT calculations how the structure (the presence or absence of substituents) and type (alcoholic, Alk, or phenolic, Ar) of tridentate ligands 2,6-pyridinobis(1,2-ethanols) [AlkONOR]H2 and 2,6-pyridinobis(1,2-phenols) [ArONOR]H2 (R = H, Me) may affect the reactivity or stabilization of tetrylene, indicating the unprecedented behavior of Main Group elements. This enables the unique control of the type of the occurring reaction. We found that unhindered [ONOH]H2 ligands predominantly led to hypercoordinated bis-liganded {[ONOH]}2Ge complexes, where an E(+2) intermediate was inserted into the ArO-H bond with subsequent H2 evolution. In contrast, substituted [ONOMe]H2 ligands gave [ONOMe]Ge: germylenes, which may be regarded as kinetic stabilized products; their transformation into E(+4) species is also thermodynamically favorable. The latter reaction is more probable for phenolic [ArONO]H2 ligands than for alcoholic [AlkONO]H2. The thermodynamics and possible intermediates of the reactions were also investigated. Full article
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21 pages, 9086 KiB  
Article
Metallogenesis and Formation of the Maliping Pb-Zn Deposit in Northeastern Yunnan: Constraints from H-O Isotopes, Fluid Inclusions, and Trace Elements
by Yongsheng Yao, Hongsheng Gong, Runsheng Han, Changqing Zhang, Peng Wu and Gang Chen
Minerals 2023, 13(6), 780; https://doi.org/10.3390/min13060780 - 7 Jun 2023
Cited by 2 | Viewed by 2014
Abstract
The Maliping large-scale Pb-Zn deposit is located in the Sichuan-Yunnan-Guizhou Pb-Zn polymetallic metallogenic triangle area (SYGT), where the Pb-Zn ore body is hosted in the interlayer fracture zone at the interface between siliceous cataclastic dolomite and clastic rocks in the Lower Cambrian Yuhucun [...] Read more.
The Maliping large-scale Pb-Zn deposit is located in the Sichuan-Yunnan-Guizhou Pb-Zn polymetallic metallogenic triangle area (SYGT), where the Pb-Zn ore body is hosted in the interlayer fracture zone at the interface between siliceous cataclastic dolomite and clastic rocks in the Lower Cambrian Yuhucun Formation and is tectonically driven. Unlike other Pb-Zn deposits hosted in the Sinian and Carboniferous carbonate rocks in the area, the metallogenic mechanism and deep and peripheral ore prospecting prediction research require further exploration. In this study, representative samples of a typical orebody profile were systematically collected, and microthermometry of fluid inclusions and H-O isotopes and metal sulfide trace element analyses were performed. The main findings were as follows: (1) The fluid inclusion study showed that the ore-forming fluids have vapor-rich phase reduction characteristics of medium-low temperature, salinity, and density. (2) H-O isotopic studies showed that the ore-forming fluids are derived from the mixing of deep-source fluids flowing through the deep fold basement (Kunyang Group) and organic containing basin brine. (3) Rare earth element (REE) characteristics indicate that the ore-forming materials were primarily derived from the folded basement (Kunyang Group). (4) The trace element study showed that sphalerite is relatively enriched in Cu, Cd, Ga, and Ge, while depleted in Fe, Mn, Sn, and Co, similar to the typical Huize-type (HZT) Pb-Zn deposit in the area. Therefore, it is suitable to explore the deposit using a large-scale “four step style” ore prospecting method for ore prospecting and prediction. Moreover, the results provide a reference for the study of Pb-Zn metallogenic systems and new ideas for the deep and peripheral prospecting of Pb-Zn deposits in this area. Full article
(This article belongs to the Special Issue Genesis and Evolution of Pb-Zn-Ag Polymetallic Deposits)
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13 pages, 858 KiB  
Article
New Inogranic Scintillators’ Application in the Electromagnetic Calorimetry in High-Energy Physics
by Dmitry Averyanov and Dmitry Blau
Appl. Sci. 2023, 13(10), 6189; https://doi.org/10.3390/app13106189 - 18 May 2023
Cited by 1 | Viewed by 1532
Abstract
Scintillation crystals Gd3Al2Ga3O12 (GAGG) are an excellent candidate for application in ionizing-radiation detectors because of their high radiation resistance, density and light yield. These crystals can be used in combination with lead tungstate (PbWO4 or [...] Read more.
Scintillation crystals Gd3Al2Ga3O12 (GAGG) are an excellent candidate for application in ionizing-radiation detectors because of their high radiation resistance, density and light yield. These crystals can be used in combination with lead tungstate (PbWO4 or PWO) crystals for the development of a new generation of electromagnetic calorimeter with advanced spatial and energy resolutions in a broad energy range. PWO crystals enable the accurate detection of high-energy photons, while GAGG crystals provide the possibility of precisely measuring photon energies, down to a few MeV. Different options for a composite electromagnetic calorimeter based on PWO and GAGG crystals are considered to optimize spatial and energy resolutions in a broad energy range (from 1 MeV to 100 GeV). In particular, different lengths of the GAGG section of the calorimeter are considered, from 0.5 to 10 cm. The separation of signals from photons and hadrons is also taken into consideration through the study of shower shape in the calorimeter. The optimization is based on Geant4 simulations, considering light collection as well as the use of different photodetectors and electronic noise. Simulations are verified with light yield measurements of GAGG samples obtained using radioactive sources and test beam measurements of the prototype of the PWO-based Photon Spectrometer of the ALICE experiment at CERN. Full article
(This article belongs to the Special Issue Inorganic Functional Materials: Synthesis and Application)
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15 pages, 4331 KiB  
Article
Silver Nanoclusters Tunable Visible Emission and Energy Transfer to Yb3+ Ions in Co-Doped GeO2-PbO Glasses for Photonic Applications
by Augusto Anselmo Amaro, Guilherme Rodrigues da Silva Mattos, Marcos Vinicius de Morais Nishimura, Jessica Dipold, Niklaus Ursus Wetter and Luciana Reyes Pires Kassab
Nanomaterials 2023, 13(7), 1177; https://doi.org/10.3390/nano13071177 - 25 Mar 2023
Cited by 6 | Viewed by 1818
Abstract
This work investigates the optical properties of Yb3+ ions doped GeO2-PbO glasses containing Ag nanoclusters (NCs), produced by the melt-quenching technique. The lack in the literature regarding the energy transfer (ET) between these species in these glasses motivated the present [...] Read more.
This work investigates the optical properties of Yb3+ ions doped GeO2-PbO glasses containing Ag nanoclusters (NCs), produced by the melt-quenching technique. The lack in the literature regarding the energy transfer (ET) between these species in these glasses motivated the present work. Tunable visible emission occurs from blue to orange depending on the Yb3+ concentration which affects the size of the Ag NCs, as observed by transmission electron microscopy. The ET mechanism from Ag NCs to Yb3+ ions (2F7/22F5/2) was attributed to the S1→T1 decay (spin-forbidden electronic transition between singlet–triplet states) and was corroborated by fast and slow lifetime decrease (at 550 nm) of Ag NCs and photoluminescence (PL) growth at 980 nm, for excitations at 355 and 405 nm. The sample with the highest Yb3+ concentration exhibits the highest PL growth under 355 nm excitation, whereas at 410 nm it is the sample with the lowest concentration. The restriction of Yb3+ ions to the growth of NCs is responsible for these effects. Thus, higher Yb3+ concentration forms smaller Ag NCs, whose excitation at 355 nm leads to more efficient ET to Yb3+ ions compared to 410 nm. These findings have potential applications in the visible to near-infrared regions, such as tunable CW laser sources and photovoltaic devices. Full article
(This article belongs to the Special Issue Advances in Photonic and Plasmonic Nanomaterials—Volume II)
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13 pages, 1976 KiB  
Article
Effect of Silver Nanoparticles on the Optical Properties of Double Line Waveguides Written by fs Laser in Nd3+-Doped GeO2-PbO Glasses
by Camila Dias da Silva Bordon, Jessica Dipold, Niklaus U. Wetter, Wagner de Rossi, Anderson Z. Freitas and Luciana R. P. Kassab
Nanomaterials 2023, 13(4), 743; https://doi.org/10.3390/nano13040743 - 16 Feb 2023
Cited by 10 | Viewed by 2268
Abstract
Nd3+-doped GeO2-PbO glass with silver (Ag) nanoparticles (NPs) are produced with double line waveguides through fs laser processing for photonic applications. A Ti:sapphire fs laser at 800 nm was used to write the waveguides directly into the glass 0.7 [...] Read more.
Nd3+-doped GeO2-PbO glass with silver (Ag) nanoparticles (NPs) are produced with double line waveguides through fs laser processing for photonic applications. A Ti:sapphire fs laser at 800 nm was used to write the waveguides directly into the glass 0.7 mm beneath the surface. This platform is based on pairs of parallel lines with spacing of 10 µm, each pair being formed by two identical written lines but in two different configurations of 4 or 8 separately processed lines, which are coincident. The results of optical microscopy, absorbance measurements, refractive index change, beam quality factor (at 632 and 1064 nm), photoluminescence, propagation losses, and relative gain at 1064 nm are presented. The structural changes in the glass due to the presence of Ag NPs were investigated by Raman spectroscopy. At 632 and 1064 nm, x,y-symmetrical guiding was observed, and for both kinds of overlapping pulses, a refractive index alteration of 10−3 was found in both directions. Photoluminescence growth of ~47% at 1064 nm was observed due to the plasmonic effect of Ag NPs. In dual waveguides containing Ag NPs, the relative gain obtained increased by 40% and 30% for four and eight overlapping lines, respectively, at 600 mW of 808 nm pump power, when compared to waveguides without those metallic NPs. We highlight the resultant positive internal gains of 5.11 and 7.12 dB/cm that showed a growth of ~40% and ~30%, respectively, with respect to the samples without Ag NPs. The increase in photoluminescence and relative gain were related to the local field growth produced by Ag NPs. The present results show that the addition of Ag NPs impacts positively on the optical performance at 1064 nm of double line waveguides processed by fs laser writing in Nd3+-doped GeO2-PbO glass, opening news perspectives for photonics. Full article
(This article belongs to the Special Issue Advances in Photonic and Plasmonic Nanomaterials—Volume II)
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17 pages, 5571 KiB  
Article
Modeling Adsorption of CO2 in Rutile Metallic Oxide Surfaces: Implications in CO2 Catalysis
by Rogelio Chávez-Rocha, Itzel Mercado-Sánchez, Ismael Vargas-Rodriguez, Joseelyne Hernández-Lima, Adán Bazán-Jiménez, Juvencio Robles and Marco A. García-Revilla
Molecules 2023, 28(4), 1776; https://doi.org/10.3390/molecules28041776 - 13 Feb 2023
Cited by 8 | Viewed by 3680
Abstract
CO2 is the most abundant greenhouse gas, and for this reason, it is the main target for finding solutions to climatic change. A strategy of environmental remediation is the transformation of CO2 to an aggregated value product to generate a carbon-neutral [...] Read more.
CO2 is the most abundant greenhouse gas, and for this reason, it is the main target for finding solutions to climatic change. A strategy of environmental remediation is the transformation of CO2 to an aggregated value product to generate a carbon-neutral cycle. CO2 reduction is a great challenge because of the large C=O dissociation energy, ~179 kcal/mol. Heterogeneous photocatalysis is a strategy to address this issue, where the adsorption process is the fundamental step. The focus of this work is the role of adsorption in CO2 reduction by means of modeling the CO2 adsorption in rutile metallic oxides (TiO2, GeO2, SnO2, IrO2 and PbO2) using Density Functional Theory (DFT) and periodic DFT methods. The comparison of adsorption on different metal oxides forming the same type of crystal structure allowed us to observe the influence of the metal in the adsorption process. In the same way, we performed a comparison of the adsorption capability between two different surface planes, (001) and (110). Two CO2 configurations were observed, linear and folded: the folded conformations were observed in TiO2, GeO2 and SnO2, while the linear conformations were present in IrO2 and PbO2. The largest adsorption efficiency was displayed by the (001) surface planes. The CO2 linear and folded configurations were related to the interaction of the oxygen on the metallic surface with the adsorbate carbon, and the linear conformations were associated with the physisorption and folded configurations with chemisorption. TiO2 was the material with the best performance for CO2 interactions during the adsorption. Full article
(This article belongs to the Special Issue Advances in the Theoretical and Computational Chemistry)
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