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Photochromic yttrium oxyhydride (YHO) shows a very attractive color-neutral darkening upon photoactivation. However, the exact defect or state responsible for the visible light absorption or the mechanism for its creation is not fully understood. This makes it challenging to optimize and modify the material. In this work, we have investigated the relationship between photon absorption and darkening profile into a YHO film. The extinction coefficient k(λ) is obtained from spectroscopic ellipsometry, and the expected photon absorption profile is calculated. This is then compared to transmittance data during photodarkening by short-wavelength UV (254 nm). Our results show that the darkening is not homogeneous through the film, showing that photon absorption and darkening are positionally correlated, yet we show that the darkening stretches further into the film than the calculated photon absorption. A homogeneously darkened sample cannot always be assumed when assessing optical transmittance, absorbance, and ellipsometry data. [ABSTRACT FROM AUTHOR]

The ultra-low thermal expansion coefficient α makes the Fe-Ni Invar alloys useful in various applications. Their low strength and low Curie temperature Tc are, however, limiting factors. Interestingly, some Fe-based bulk metallic glasses (BMGs), with inherent high strength, exhibit the clear Invar effect. In particular, the (Fe71.2B24Y4.8)96Nb4 BMG has the lowest α among Fe-based BMGs, but it unfortunately also has the lowest Tc. In this work, silicon was added into this alloy with the aim to elevate Tc while maintaining a low α. It was found that when silicon partially substituted boron, Tc did not increase significantly but α did, which is not ideal. On the other hand, when silicon partially substituted yttrium and niobium and especially niobium, Tc increased significantly while α did not, which is close to the ideal scenario. When 3% of niobium was substituted by silicon, Tc reached the maximum value of 296 °C while α remained a low value of 7.4 × 10−6/°C. Comparing to the Fe-Ni Invar alloy, although this BMG has an inferior α, it has much higher Tc (+115 °C) and strength (∼9 times), presenting a potential for application as a new Invar material with moderate (low) thermal expansion, high operating temperature, and high strength. [ABSTRACT FROM AUTHOR]

Ultrafine WC-Co cemented carbide has superior performance of high strength and high hardness, which is widely used in industrial fields. In the traditional process, high temperature carburization method is used to prepare tungsten carbide, and solid-phase mechanical milling method is used to mix grain growth inhibitor (Cr 3 C 2) and tungsten carbide, which easily lead to large WC particle size and uneven WC grain size distribution in WC-Co cemented carbide, thus affecting mechanical properties of the alloy. In the new process, based on the genetic relationship between the particle size of ammonium paratungstate and tungsten carbide, ultrafine ammonium paratungstate uniformly doped with yttrium was firstly obtained by adding a certain amount of ammonia and yttrium oxide into the ammonium metatungstate solution. Then the ammonium paratungstate was calcined to obtain yttrium-doped tungsten trioxide, which was then converted into yttrium-doped ultrafine tungsten carbide powders by introducing carbon monoxide at a low temperature. Finally, the ultrafine WC-Co cemented carbide was prepared by pressure sintering. During the neutralization and crystallization process of ammonium metatungstate solution, the yttrium-doped ultrafine ammonium paratungstate (Fischer particle size 8.4 μm) with narrow particle size distribution and regular morphology was prepared. The yttrium-doped ammonium paratungstate was calcined at 500 °C for 90 min in air atmosphere to obtain yttrium-doped tungsten trioxide powder with a Fischer particle size of 4.5 μm and narrow size distribution. Then the yttrium-doped tungsten trioxide and carbon monoxide gas were reacted at 920 °C for 3h to obtain yttrium-doped ultrafine tungsten carbide powder with a Fischer particle size of 0.32 μm and a specific surface area of 4.44 m2/g, and ultrafine WC-Co cemented carbide with tungsten carbide grain size of 0.28 μm was obtained by pressure sintering. The yttrium uniform distributed effectively inhibited the abnormal growth of tungsten carbide grains. Compared with the WC-Co cemented carbide prepared by solid-phase mechanically mixing tungsten carbide powder and chromium carbide, the yttrium-doped WC-Co cemented carbide had a smaller average tungsten carbide grain size and a more homogeneous microstructure. The prepared yttrium-doped WC-Co cemented carbide had a hardness (HRA) of 94.6, a bending strength of 4841 M, and a coercive force of 42.3 KA/c. [ABSTRACT FROM AUTHOR]

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In the semiconductor industry, the long "seasoning" time required after the installation of new ceramic components in etching equipment restricts the wafer production efficiency. This study proposes a novel and practical method for the fabrication of pre-seasoned ceramics through surface modification of Y 2 O 3 ceramics. Fluorine-containing reactive vapors were produced by utilizing NH 4 F as the source. Further, the formation of yttrium oxyfluoride layers on the surfaces of Y 2 O 3 ceramics was demonstrated. The modified surface comprises a single-crystalline phase near the interface with the Y 2 O 3 substrate. The change in the composition, crystalline nature of the modified layer, and orientation relationship with the substrate were examined via transmission electron microscopy. The kinetics of the surface modification were studied for the sintered Y 2 O 3 bulk as well as for practical coatings such as plasma-sprayed or PVD coatings. The proposed surface modification approach can be used to fabricate pre-seasoned Y 2 O 3 coatings, which can significantly benefit the semiconductor industry. [ABSTRACT FROM AUTHOR]

Yttrium-containing ceramics exhibit excellent resistance to water-oxygen corrosion, making them an attractive choice as the modified matrix for SiC f /SiC composites. However, the oxidation products of yttrium-containing ceramics are complex and vary widely in performance. In this study, YSOC ceramics, which are composed of yttrium silicate, SiO 2 , and SiC, were prepared using Y 2 O 3 , SiO 2 , SiC, and Li 2 CO 3. This research investigated the effects of high temperatures, air oxidation, and water-oxygen corrosion on the phase compositions of YSOC ceramics. The influence of environmental factors on the synthesis and decomposition of yttrium silicate was analyzed. Moreover, the study explored the compatibility of different oxidation products with SiC. The results suggest that Y 2 SiO 5 and Y 2 Si 2 O 7 are formed through the low eutectic of SiO 2 , Y 2 O 3 , and Li 2 CO 3. The high SiO 2 content likely contributes to the relatively low formation temperature of Y 2 Si 2 O 7. In the oxidizing environment, Y 2 SiO 5 reacts with SiO 2 to produce Y 2 Si 2 O 7. Conversely, in the water vapor-containing atmosphere, Y 2 Si 2 O 7 undergoes hydrolysis to form Y 2 SiO 5. Y 2 Si 2 O 7 displays a reduced elastic modulus in comparison to SiC fibers and exhibits favorable physical and chemical compatibility with SiC fibers. However, the hydrolysis of Y 2 Si 2 O 7 may potentially affect the water-oxygen corrosion resistance of the ceramics. These findings will significantly advance research and enhance understanding of the water-oxygen corrosion behaviors of yttrium-containing matrix-modified composites. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusions An organ‐specific Positron emission tomography (PET) scanner can achieve the same sensitivity with much fewer detectors as compared to a whole‐body PET scanner, thereby substantially reducing the system cost. It can also achieve much better spatial resolution as compared to a whole‐body PET scanner since the photon noncollinearity effect is reduced by using smaller detector ring diameter. Consequently, the development of organ‐specific PET scanners with high spatial resolution, high sensitivity, and low cost has been a major focus of international research in PET instrument development for many years.The focus of this work is to develop high‐resolution depth encoding PET detectors with high timing resolution and a reduced number of signal processing electronic channels. Consequently, PET scanners tailored for specific organs can be developed with high spatial and timing resolutions, enhanced sensitivity, and affordable cost.An 8 × 8 silicon photomultiplier (SiPM) array with a pixel size of 3 × 3 mm2 and a multiplexed signal readout circuit is coupled to one end of the lutetium yttrium orthosilicate (LYSO) array with a glass light guide between them to achieve a good crystal identification of small crystals by using only four position‐encoding energy signals. A 4 × 4 SiPM array with a pixel size of 6 × 6 mm2 and an individual readout circuit is coupled to the other end of the crystal array without a light guide to achieve a good coincidence timing resolution (CTR). The depth of interaction (DOI) of the detector is measured by ratio of the energies measured by the two SiPM arrays and can be used to correct the depth dependency of the timing. The flood histograms, energy resolutions (ERs), DOI resolutions, and CTRs of two detectors utilizing LYSO arrays with different crystal sizes were measured with each of the two SiPM arrays alternately placed at the front of the detectors.A better flood histogram was obtained by placing the 8 × 8 SiPM array in front of the detector. The depth dependency of timing was larger when the 4 × 4 SiPM array was placed at the front of the detector. A better CTR was obtained by placing the 4 × 4 SiPM array at the back of the detector as compared to placing it at the front of the detector if the depth‐dependent timing correction was not performed. If the depth‐dependent timing correction was performed, a better CTR can be obtained by placing the 4 × 4 SiPM array at the front of the detector. The first detector using a 12 × 12 LYSO crystal array with a crystal size of 1.95 × 1.95 × 20 mm3 provided a flood histogram with all crystals clearly resolved, an ER of 11.7%, a DOI resolution of 2.9 mm, and a CTR of 275 ps with the depth‐dependent timing correction. The second detector using a 23 × 23 LYSO crystal array with a crystal size of 0.95 × 0.95 × 20 mm3 provided a flood histogram with all but the edge crystals clearly resolved, an ER of 17.6%, a DOI resolution of 2.3 mm, and a CTR of 293 ps with the depth‐dependent timing correction.PET detectors with small crystal cross‐sectional sizes, good DOI and timing resolutions and a reduced number of electronics channels were developed. The detectors can be used to develop high performance organ‐specific PET scanners. [ABSTRACT FROM AUTHOR]

Reactions of the yttrium complex [AdNPPh2]3Y (1) with CoCl2 and FeCl2 led to the isolation of a heterobimetallic Y(III)–Co(II) complex and a diiron complex [AdNPPh2]3Fe2Cl (4), respectively. In the presence of KC8/18-c-6 as a reductant, the reaction of 1 with CoCl2 afforded a dicobalt complex [AdNPPh2]3Co2ClK(18-c-6) (3). These reactions proceeded via ligand redistributions caused by halide abstraction from the Lewis acidic and electropositive Y(III) center. Treatment of the β-diketiminato yttrium complex LnacnacY[PhNCH2PPh2]2 (5) with FeCl2 led to the formation of the complex [PhNCH2PPh2]2[PhN(Ph)NCH2PPh2]Fe2Cl (6), via ligand redistribution and P–C bond cleavage. All complexes are paramagnetic and are characterized by X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

For successful 3D printing based on stereolithography technologies, one of the most important factors influencing the success of printing is the dynamic viscosity of the prepared suspension. For the purposes of viscosity prediction at different volume fillings, two ZrO 2 powders with different yttrium content (CY3Z-RS and CY8Z-RS) with volume filling 0–40 % in two different dispersing mediums at two temperatures were investigated in this paper. The dependence of relative viscosity on volumetric filling was fitted by existing models and a new semi-empirical model based on experimental data was proposed and successfully plotted. Fitted data for all zirconia photosensitive suspensions showed a high correlation to the proposed model (R 2 from 97.02 % to 99.61 %). The model in addition to the possibilities of mathematical generalization of his prescription, introduces a fitting parameter C , which is thought to be thermodynamically influenceable and predictable. Furthermore, another key characteristic that is often neglected in rheological characterization, the stability of prepared ceramic suspensions, was verified either by rheological measurements but also by employing prospective technology based on analytical centrifuge. It was confirmed that all prepared suspensions were highly stable, and all instability indexes reached values less than 0.05. [ABSTRACT FROM AUTHOR]

This study investigated the influence of carbon source on the microstructure and water–oxygen corrosion behavior of Si–Y alloy modified SiC/SiC composites. The results indicated that incorporating a small-sized and diffusely distributed carbon source within the matrix not only facilitates the preparation of a highly dense matrix, but also enables a uniform dispersion of the reaction-generated SiC. Furthermore, with the assistance of residual Si–Y alloy, the dispersed SiC enhanced the matrix strength, leading to a stepwise fracture behavior of the composites. Yttrium silicate with a gradient structure formed around the dispersed SiC could effectively exert its water–oxygen corrosion resistance. After 100 h of water–oxygen corrosion test at 1300 °C, the flexural strength of the composites with this structure reached 416 MPa, with a retention rate of 85 %. Both bending strength and retention were found to be at a high level in the current research on matrix modification. [ABSTRACT FROM AUTHOR]

AbstractThis paper highlighted in preparation and their properties of Y3+ doped barium titanate (BaTiO3) nanocrystals using inverse miniemulsion. The yttrium (Y) element dopant as the earlier utilized rare earth was used for barium titanate (BaTiO3) modification. The cubic structure of Y3+ doped BaTiO3 nanocrystals were successfully incubated in stable droplets of inverse miniemulsion under the solvent-thermal treatment condition. The suitable Y3+ doping amount in nanocrystals had positively attributed to reduce the value of bandgap (Eg), to prolong the fluorescence lifetime, and to improve the photoelectric properties. The photodegradation mechanism and the schematic diagram of fluorescence emission and radical production were suggested for explanation the relation between photoelectric characteristics and photocatalytic properties. The selected 1.0% Y3+ doped nanocrystal provided an excellent photocatalysis candidate for organic compound photodegradation. [ABSTRACT FROM AUTHOR]

Rare earth elements (REEs) are crucial additives in the iron and steel industry. The accurate determination of thermodynamic data is fundamental for applying REEs in steel production; however, this has proven challenging due to their strong reactivity with refractory materials. This study assessed the thermodynamic data for the yttrium–oxygen equilibrium in liquid iron, using high‐temperature experiments with high‐purity Y2O3 crucibles as the smelting container. More reliable equilibrium constants and first‐order interaction coefficients are obtained by minimizing the reactions between yttrium and the crucible while ensuring favorable kinetic conditions. The results confirm that the deoxidation product of yttrium in liquid iron is Y2O3, and the equilibrium constant for the reaction Y2O3(s) = 2[Y] + 3[O] can be expressed as follows: logKY(KYO=aY2aO3/aY2O3)=−63585/T+20.18, 1600−1700 °C$$ \mathrm{log}{K}_{\text{Y}}({K}_{\text{Y}}^{\text{O}}={a}_{\text{Y}}^{2}{a}_{\text{O}}^{3}/{a}_{{\text{Y}}_{2}{\text{O}}_{3}})=-63585/T&amp;amp;amp;amp;amp;amp;amp;amp;plus;20.18,&amp;amp;amp;amp;amp;amp;amp;amp;nbsp;1600-1700&amp;amp;amp;amp;amp;amp;amp;amp;nbsp;&amp;amp;amp;amp;amp;amp;amp;amp;deg;\mathrm{C}$$. K′Y=([%Y]2[%O]3)$K &amp;amp;amp;amp;amp;amp;amp;amp;aposx;_{\text{Y}} &amp;amp;amp;amp;amp;amp;amp;amp;equals; \left(\right. \left(\left[\right. \% \text{Y} \left]\right.\right)^{2} \left(\left[\right. \% \text{O} \left]\right.\right)^{3} \left.\right)$ can be expressed as: logK′Y=logKY−(−31028/T+8.06)(3[%Y]+11.1[%O]), 0.003 wt%<[Y]<0.23 wt%$$ \mathrm{log}K{\prime }_{\text{Y}}=\mathrm{log}{K}_{\text{Y}}-(-31028/T&amp;amp;amp;amp;amp;amp;amp;amp;plus;8.06)(3[\%\text{Y}]&amp;amp;amp;amp;amp;amp;amp;amp;plus;11.1[\%\text{O}]),&amp;amp;amp;amp;amp;amp;amp;amp;nbsp;0.003&amp;amp;amp;amp;amp;amp;amp;amp;nbsp;\text{wt\%}&amp;amp;amp;amp;amp;amp;amp;lt;[\text{Y}]&amp;amp;amp;amp;amp;amp;amp;lt;0.23&amp;amp;amp;amp;amp;amp;amp;amp;nbsp;\text{wt\%}$$. The first‐order interaction coefficient can be presented as: eOY=−31028/T+8.06$e_{\text{O}}^{\text{Y}} &amp;amp;amp;amp;amp;amp;amp;amp;equals; - 31028 / T &amp;amp;amp;amp;amp;amp;amp;amp;plus; 8.06$. [ABSTRACT FROM AUTHOR]

Using Y(NO3)3 • 6H2 O as yttrium source, nano-sized Y2 O3 powder was obtained by calcining the precursor prepared by Pechini method. This Y2O3 powder was then used as a sintering additive to fabricate transparent AlON ceramics via pressureless sintering at 1 880 °C for 2. 5 h. The effects of precursor calcination temperature on the composition, morphology and particle size of Y2O3 powder, as well as on the transparency of AlON ceramics were thoroughly studied. The results indicate that increasing calcination temperature of the precursor can promote the decomposition of organic compounds, but it also leads to the growth of Y2 O3 particles. Residual organic compounds and excessive growth of Y2 O3 powders are unfavorable for fabrication of AlON ceramics with high transmittance and high relative density. The nano-sized Y2 O3 powder prepared by calcining the precursor at 900 °C for 2 h is favorable for the fabrication of highly transparent AlON ceramics via rapid pressureless sintering. The infrared transmittance of the obtained AlON ceramics reaches up to 83.4% at ~ 3 750 nm. [ABSTRACT FROM AUTHOR]

The development direction of advanced solid-state lasers is higher output power and better beam quality. Rare earth ion doped yttrium aluminum garnet transparent ceramics are preferred materials for solid-state laser gain media, but thermal effects during the pumping process deteriorate the beam quality and hinder further increase in output power. The heat generation and dissipation of laser ceramics with complex configurations are more uniform during the pumping process, which can significantly reduce thermal effects. Compared with traditional preparation methods, 3D printing is able to form more complex design structures, suppress thermal effects, and achieve integration and miniaturisation of multi-module devices, driving lasers towards a wider range of applications. In this paper, several traditional methods for the preparation of laser ceramics with complex configurations are introduced firstly, and the advantages and limitations are analyzed. Then, the research status and problems in 3D printing yttrium aluminum garnet-based laser ceramics are systematically reviewed. Common 3D printing methods include direct ink writing, stereolithography, digital light processing, material jet printing, two-photon polymerization and micro-continuous liquid interface printing. Among them, there are interlayer defects in the samples printed by stereolithography and digital light processing, resulting in severe scattering losses. Material jetting printing combined with dry pressing can be used to manufacture planar waveguides. Two-photon polymerization and micro-continuous liquid interface printing are suitable for the fabrication of highly complex structures at micrometer scales. Direct ink writing not only enables the fabrication of laser ceramics for the first time, but also has the most extensive relevant research and is still the most promising method for the preparation of laser ceramics with complex configuration. At the end of this paper, the current problems and research prospects of yttrium aluminum garnet-based laser ceramics prepared by 3D printing are summarized. [ABSTRACT FROM AUTHOR]

STACK family borates are promising compounds for optical applications. Synthesis and luminescence of Sr3Y(BO3)3 borate belonging to the STACK family is described. Trivalent activators Tb3+ and Gd3+ occupy yttrium sites. Owing to fixed, well-separated positions (Y–Y distance 7.396 Å), a large concentration of Gd3+, as much as 50% relative to Y, could be accommodated without causing concentration quenching. In the case of Gd3+, both excitation and emission lines arise in f–f transitions. Photoluminescence emission is obtained in UV regions. In the case of Tb3+, concentration quenching was observed above 2%. Prominent excitation of Tb3+ is in the form of a band arising in the f–d-type transition, while emission comes from f–f transitions. Emission lifetimes are of the order of milliseconds, typically forbidden f–f transitions. [ABSTRACT FROM AUTHOR]

We compare trends in experimental observations reported by Zhou et al. to relevant results from numerous previously published studies. Based on these comparisons, we question the reliability of the gibbsite titration data and consider the cation uptake curves to be incomplete and questionable as well. The adsorption edges in Zhou et al. are too flat compared to the typical adsorption edges reported in hundreds of studies. Finally, we are convinced that trends of cation adsorption with NaNO3 content not only disagree with relevant, previously published results, but are even opposite to trends expected with increasing ionic strength, whenever such effects are observed. Finally, we discuss other inconsistencies in the experimental data. [ABSTRACT FROM AUTHOR]

STACK family borates are promising compounds for optical applications. Synthesis and luminescence of Sr3Y(BO3)3 borate belonging to the STACK family is described. Trivalent activators Tb3+ and Gd3+ occupy yttrium sites. Owing to fixed, well-separated positions (Y–Y distance 7.396 Å), a large concentration of Gd3+, as much as 50% relative to Y, could be accommodated without causing concentration quenching. In the case of Gd3+, both excitation and emission lines arise in f–f transitions. Photoluminescence emission is obtained in UV regions. In the case of Tb3+, concentration quenching was observed above 2%. Prominent excitation of Tb3+ is in the form of a band arising in the f–d-type transition, while emission comes from f–f transitions. Emission lifetimes are of the order of milliseconds, typically forbidden f–f transitions. [ABSTRACT FROM AUTHOR]

Yttrium oxyfluoride (YOF) coatings with different oxygen content were prepared using atmospheric plasma spraying (APS) technology. The etching resistance of the coatings in HBr/O2 plasma was investigated. Shifts in diffraction peaks of the X-ray diffraction, along with XPS analysis conducted before and after etching, demonstrated that Br ions could replace O and F ions and fill the oxygen vacancies after exposure to HBr/O2 plasma, which is supported by the first-principles calculations. Br ions formed a protective layer on the surface of the YOF coating, slowing down further etching by Br ions. By adjusting the oxygen mass fraction in YOF powder, the oxygen vacancy concentration and Br ion filling were regulated to enhance etching resistance. YOF coatings with 6% oxygen content exhibited improved etching resistance compared to YOF coatings with 3% and 9% oxygen content. This improvement was primarily due to the increased Br ion concentration. These findings provide a new approach for developing coatings with enhanced etching resistance. [ABSTRACT FROM AUTHOR]

The structural features and luminescent properties of heterometallic Tb–Gd, Tb–La, and Tb–Y terephthalate metal–organic frameworks, namely (TbxM1−x)2(1,4-bdc)3∙4H2O (M = Gd, La, Y), were studied in detail in a wide concentration range (x = 0.001–1). The crystalline phase of synthesized compounds corresponds to Ln2(1,4-bdc)3·4H2O. The lifetime of 5D4 decreased with increased Tb3+ concentration, but PLQY depends non-linearly on the Tb3+ concentration. The 50% substitution of Tb3+ for Y3+, Gd3+, or La3+ ions result in the significant enhancement of photoluminescence quantum yield, up to 1.6 times. The morphology, thermal stability, and vibrational structure of the selected homo- and bi-metallic materials is reported as well. [ABSTRACT FROM AUTHOR]

A new rare‐earth reduction system is described in which trivalent yttrium and dysprosium react as though present in their unstable divalent oxidation state. This masked divalent reactivity is achieved using the isocarbonyl‐bridged dimers [( Cp2ttt ${{{\rm { Cp}}}_{{\rm { 2}}}^{{\rm { ttt}}}}$ M)(μ‐Fp)]2 (M=Y, 1Y; M=Dy, 1Dy; Cpttt=1,2,4‐C5tBu3H2; Fp=CpFe(CO)2), where the reducing electrons originate from the bridging [Fp]− ligands. The reactivity of 1Y and 1Dy is showcased by reducing the N‐heterocycles 2,2′‐bipyridyl (bipy), phenazine (phnz) and hexaazatrinaphthylene (HAN) to give corresponding mono‐, di‐ and tri‐metallic rare‐earth complexes, respectively, with the heterocyclic ligands present in their singly, doubly and triply reduced forms, respectively. The dynamic magnetic properties of the dysprosium compounds are described. Compound 1Dy is a single‐molecule magnet (SMM) with an appreciable energy barrier of 449(17) cm−1, whereas [( Cp2ttt ${{{\rm { Cp}}}_{{\rm { 2}}}^{{\rm { ttt}}}}$ Dy)2(μ‐phnz)] (3Dy) is not an SMM because of a strong, competing equatorial crystal field. Surprisingly, [( Cp2ttt ${{{\rm { Cp}}}_{{\rm { 2}}}^{{\rm { ttt}}}}$ Dy)3(HAN)] (4Dy) is also not an SMM, the origins of which are traced to the impact of the tert‐butyl substituents on the dysprosium centre and its interaction with the radical [HAN]3− ligand. [ABSTRACT FROM AUTHOR]

The solid solution Ba 5 In 2– x Y x Al 2 ZrO 13 (0 ≤ х ≤0.50) with hexagonal structure (space group P 6 3 / mmc) was prepared by the solid-state reaction method. The effects of isovalent Y3+-substitution on the structure, hydration, bandgap and transport properties have been investigated. The introduction of yttrium was accompanied by lattice expansion, which led to an increase in the concentration of protons during hydration. The doping did not lead to a significant increase in oxygen-ion conductivity since there was no change in oxygen stoichiometry. At the same time, doping led to an increase in ionic transport numbers due to a decrease in hole conductivity. Proton conductivity contribution and the values of proton conductivity increase with the increase in yttrium concentration. The phases with yttrium content x > 0.2 were predominant proton conductors at the temperature below 600°С under wet air. [ABSTRACT FROM AUTHOR]

This paper systematically investigates the electronic structure and optical properties of zinc-blende ZnTe, ZnS systems, ZnTe/ZnS heterojunctions, and Y-doped ZnTe/ZnS heterostructions using the generalized gradient approximation (GGA) method under the density functional theory (DFT) framework. The results show that compared to the single-component ZnTe or ZnS systems, the ZnTe/ZnS heterojunction has a smaller bandgap width and undergoes a redshift in the absorption spectrum, which is favorable for more valence band electrons to be excited by light and transition to the conduction band, thereby enhancing the optoelectronic properties of the material. After Y-doping in the ZnTe/ZnS heterojunction system, when the doping concentration is between 1.56 at% and 4.69 at%, doping Y in the ZnS layer would result in the lowest energy formation of the system. Therefore, it can be inferred that in experiments, if the doping concentration is increased beyond this range, Y atoms are more likely to be arranged in the ZnS layer. Compared with the pure ZnTe/ZnS heterojunction system, increasing the Y doping concentration results in a wider bandgap and a more prominent blue shift in the absorption spectrum. Therefore, it is possible to adjust the bandgap of the heterojunction by changing the doping concentration to fabricate heterojunction device with different photoelectric effects and luminescence properties. [ABSTRACT FROM AUTHOR]

Fine powders of yttrium orthoniobate activated by Eu, Sm, Tb, Er have been synthesized by the sol-gel. The synthesized powders have been calcined at different temperatures (1000, 1100 and 1180 °C). Luminescent ceramics (Y 0.96 Еu 0.01 Sm 0.01 Tb 0.01 Er 0.01)NbO 4 were prepared from fine powders by uniaxial hot pressing (UHP) via various technological modes. For the first time, the crystal structure, microstructure, spectral composition, photoluminescence properties of (Y 0.96 Еu 0.01 Sm 0.01 Tb 0.01 Er 0.01)NbO 4 ceramics have been studied depending on the temperature conditions of the synthesis of powders and UHP conditions during sintering of ceramics. The mechanical properties of these ceramics (Young's modulus, microhardness and critical stress intensity factor for the mode I K IC) have been evaluated. [ABSTRACT FROM AUTHOR]

Cerium oxide (CeO2) and yttrium oxide (Y2O3) nanoparticles possess interesting surface properties and interfacial interactions that make them attractive candidates for various applications. This study presents a comprehensive investigation into the synthesis and toxicity assessment of yttrium-doped cerium oxide (Ce-Y) nanocomposite using a combination of analytical techniques and biological assays. The nanocomposite was characterized using UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), electron microscopy imaging, dynamic light scattering (DLS), and zeta potential measurements to elucidate their structural, optical and physicochemical properties. The synthesized nanocomposite exhibited distinctive absorption spectra and precise alignment of diffraction peaks, confirming the successful incorporation of yttrium ions into the cerium oxide lattice. Electron microscopy images revealed well-dispersed yttrium particles within the ceria matrix, indicating uniform distribution and morphology. DLS and zeta potential analysis provided insights into the size distribution and stability of the nanocomposite. Furthermore, in vivo toxicity assessment using Drosophila melanogaster model revealed no significant toxicity of Ce:Y nanocomposite, as evidenced by survival assay and behavioral assays. Superoxide dismutase (SOD) activity and reactive oxygen species (ROS) levels were also evaluated, demonstrating no discernible nanoparticle-induced toxicity. Overall, this study highlights the potential applications of Ce:Y nanocomposite and underscores the importance of comprehensive toxicity evaluation in nanomaterial development. [ABSTRACT FROM AUTHOR]

Exploring the surface organometallic chemistry on silica of highly electrophilic yttrium complexes is a relatively uncommon endeavor, particularly when focusing on tris‐alkyl complexes characterized by Y−C σ‐alkyl bonds. A drawback with this class of complexes once grafted on silica, is the frequent occurrence of alkyl transfer by ring opening of siloxane groups, resulting in a mixture of species. Herein, we employed a more stable homoleptic yttrium allyl complex bearing bulky η3‐1,3‐bis(trimethylsilyl)allyl ligand to limit this transfer reaction. This strategy has been validated by comparing the reactivity between [Y{ η3‐1,3‐C3H3(SiMe3)2}3] and [Y(o‐CH2PhNMe2)3] with SiO2–700, where the undesired alkyl transfer reaction occurred for [Y(o‐CH2PhNMe2)3] leading to a bipodal [(≡SiO)2Y(o‐CH2PhNMe2)] as major surface species, 2, while [Y{ η 3‐1,3‐C3H3(SiMe3)2}3] resulted selectively in a monopodal species, [(≡SiO)Y{η3‐1,3‐C3H3(SiMe3)2}2], 1. The materials obtained were characterized by DRIFT, solid state NMR, mass balance analysis and EXAFS. Catalyst 1 showed high activity compared to 2 in ethylene polymerization. The catalytic performance of this neutral catalyst 1 was extended to pre‐industrial scale in the presence of hydrogen and 1‐hexene. An unprecedented activity, up to 7400 gPE gcat−1 h−1 was obtained even with very low concentration of scavenger AliBu3 (TIBA/Y=1.2). The obtained HDPE exhibited desired spherical particle morphology with broad molar mass distribution. [ABSTRACT FROM AUTHOR]

Utilizing ternary mixtures [LnMe3]n/K(2,4‐dtbp)/GaMe3 (Ln=Lu, Y; 2,4‐dtbp=2,4‐di‐tert‐butyl‐pentadienyl), a series of metallacycles is accessible via tandem salt metathesis/deprotonation. Depending on the precursor molar ratio, both gallatabenzene and lutetacyclic moieties with fully planar metallacycles are obtained, which were further analyzed using DFT calculations. The precursor molar ratio affects the extent of pentadienyl C−H‐bond activation and oligomerization to tetra‐ and pentametallic arrays. Reacting a 1 : 2 : 2 mixture at −40 °C gave the open sandwich methyl complex (2,4‐dtbp)2Lu(CH3), displaying a vital intermediate for subsequent ring‐closure reactions. [ABSTRACT FROM AUTHOR]

The spectra of luminescence and magnetic circular polarization of a single crystal of thulium-yttrium garnet-aluminate Tm3+:YAG have been studied within the visible spectral range at a temperature of 90 and 300 K in a magnetic field of 10 kOe. Based on the analysis of optical and magneto-optical data, the presence of "quasi-degenerate" states of excited multiplets ¹D2, ³F4,³G4 and the ground multiplet ³H6 of the Tm3+ RE ion in garnet-aluminate YAG at the radiative transitions ¹G4→³H6, ¹D2→³F4 and ¹D2→3F3 has been determined. The effect of quantum mechanical "mixing" plays a significant role in the occurrence of magneto-optical effects on luminescence bands caused by "forbidden" 4f→4f transitions in the non-Kramers Tm3+ ion having a "quasi-doublet" structure in the energy spectra. [ABSTRACT FROM AUTHOR]

Nanotechnology has a significant impact on different fields such as medicine, information technology, energy, advanced materials, textiles, and many other new areas. In this study, the characterization of the green synthesized and chemically synthesized nanoparticle from Tribulis terrestris was studied. Yttrium nitrate hexahydrate was employed as a precursor material for the synthesis of nanoparticles. Characterization study was performed by using UV–Vis spectroscopy, FTIR, FE-SEM. For green synthesis, the peak was observed at 311 nm while for chemically synthesized nanoparticles the maximum peak absorption was seen at 239 nm. The FTIR analysis for green synthesized nanoparticles reveals the presence of three prominent peaks due to C–O stretching vibration, C–O bending vibration and Y–O vibration. Chemically synthesized nanoparticles show the presence of C–O stretching vibration, C–O bending vibration and OH-stretching. The results of SEM studies indicated the particle shape and size of chemically synthesized nanoparticles and green synthesized nanoparticles. Green synthesized Y2O3 NPs are an appropriate option for use in medicinal applications. Furthermore, detailed in vivo studies are needed to determine the safety and effectiveness of these green synthesized Y2O3 nanoparticles. [ABSTRACT FROM AUTHOR]

This study investigates the gamma-ray attenuation capabilities of ABS polymer reinforced with nano-sized yttrium particles. The analysis focuses on three key parameters: mass attenuation coefficient, half-value layer, and radiation protection efficiency. Utilizing a sol–gel process for polymer molding, various test samples were prepared and subjected to scanning electron microscopy (SEM) for surface structure examination. Then, experimental, theoretical, and simulation approaches are used to obtain gamma-ray shielding parameters. The base and additive materials are chosen as ABS polymer and yttrium nanoparticles, respectively, and the results revealed a consistent enhancement in gamma-ray attenuation characteristics with the incorporation of yttrium nanoparticles. These findings offer valuable perspectives for advancing the development of sophisticated radiation shielding materials, presenting potential applications across diverse fields including medical imaging, industrial processes, and nuclear technologies. [ABSTRACT FROM AUTHOR]

A new nanodevice based on gold nanoparticles (AuNPs) capped with poly(diethylvinylphosphonate) (PDEVP) has been synthesized, showing interesting photophysical and thermoresponsive properties. The synthesis involves a properly designed Yttriocene catalyst coordinating the vinyl-lutidine (VL) initiator active in diethyl vinyl phosphonate polymerization. The unsaturated PDEVP chain ending was thioacetylated, deacetylated, and reacted with tetrachloroauric acid and sodium borohydride to form PDEVP-VL-capped AuNPs. The NMR, UV–Vis, and ESI-MS characterization of the metal nanoparticles confirmed the formation of the synthetic intermediates and the expected colloidal systems. AuNPs of subnanometric size were determined by WAXD and UV–Vis analysis. UV–Vis and fluorescence analysis confirmed the effective anchoring of the thiolated PDEVP to AuNPs. The formation of 50–200 nm globular structures was assessed by SEM and AFM microscopy in solid state and confirmed by DLS in aqueous dispersion. Hydrodynamic radius studies showed colloidal contraction with temperature, demonstrating thermoresponsive behavior. These properties suggest potential biomedical applications for the photoablation of malignant cells or controlled drug delivery induced by light or heat for the novel PDEVP-capped AuNP systems. [ABSTRACT FROM AUTHOR]

In this study, D2 steel (Cr12Mo1V1) with different yttrium (Y) contents was designed, and the effects of Y on the inclusions and eutectic carbides of D2 steel after casting were analyzed by scanning electron microscopy, ASPEX, and electron probe microanalyzer. The results reveal that the inclusions in D2 steel without Y are mainly Al2O3 and MnS, while the inclusions with Y are mainly Y2S3, Y2O2S, and complex inclusions. When the Y content increased from 0 to 0.021%, the quantity of inclusions with an average grain size of 1–2 microns gradually increased from 47.6 to 64.7%. The chain eutectic carbides in D2 were broken and tend to be spheroidized after adding Y, which was attributed to the fact that the submicron Y-rich inclusions help to slow down the segregation of carbon and alloying elements. The inclusion is beneficial to the heterogeneous nucleation of M7C3 eutectic carbides and the decrease in eutectic reaction temperature. [ABSTRACT FROM AUTHOR]

It is imperative to enhance the mechanical properties and corrosion resistance of magnesium (Mg)-based metallic glasses for orthopedic implants to further their development. The addition of yttrium (Y) significantly improves both of these characteristics. The Mg52.5Zn40.5Ca5Y2 alloy was chosen for its optimal glass-forming capabilities, as evidenced by thermodynamic parameter, PHHS. This alloy demonstrates remarkable enhancements in both mechanical and corrosion properties, despite the presence of a stable Mg12YZn phase in the liquid, which precludes the complete formation of glass. The Mg52.5Zn40.5Ca5Y2 alloy exhibits a substantial increase in hardness, surpassing the Mg66Zn30Ca4 metallic glass by up to 30 HV. The compressive strength of this alloy is 690 MPa, which is approximately 138 MPa greater than that of the Mg66Zn30Ca4 alloy. The Mg52.5Zn40.5Ca5Y2 alloy exhibits a higher noble corrosion potential and a lower corrosion current density demonstrating a corrosion current density of 6.970 µA/cm2 and a corrosion potential of − 1.240 V. These values suggest a significant increase in corrosion resistance when contrasted with the baseline alloy, Mg66Zn30Ca4. The primary cause of this improvement in mechanical behavior and corrosion resistance is the formation of Mg12YZn long-period stacking ordered (LPSO) phases and Mg3YZn6 icosahedral phases. The material's overall strength and durability are enhanced by these phases, rendering it a promising candidate for applications that necessitate high performance in both mechanical and corrosive environments. As per the results, Mg52.5Zn40.5Ca5Y2 alloy is an exceptional choice for advanced material applications due to its distinctive phase composition, which results in superior properties. [ABSTRACT FROM AUTHOR]

The effects of yttrium on the microstructures and properties of Cu45.12Zr45.12Al5.76Nb4 bulk metallic glass composites were investigated. It was found that yttrium addition could effectively control the distribution and volume fraction of B2-CuZr precipitated phase in the composites by adjusting the glass-forming ability of the alloys, and suppress the eutectoid decomposition of B2-CuZr.Within 2 at.% yttrium addition, the volume fraction of B2-CuZr precipitation in the glassy matrix decreases significantly with the increase of yttrium content. For more than 2 at.% yttrium addition, the volume fraction of B2-CuZr precipitation increases as yttrium content increases. An optimal amount of yttrium (2–3 at.%) enhances glass-forming ability of the alloy, reduces B2-CuZr precipitation, and obviously improves the agglomeration and distribution uniformity of B2-CuZr in the amorphous matrix. The compressive properties of BMG composites with more than 1 at.% yttrium addition drop considerably, which should be mainly attributed to the abundant and various forms of Y2O3 brittle phase formed in the glassy matrix. [ABSTRACT FROM AUTHOR]

Yttrium barium copper oxide (YBCO) is used for special applications in linear generators because of its excitation loss, lower weight, and higher efficiency. These qualities enable the compound to operate better than the conventional copper wire coil in the stator unit of the linear generator. However, the continuous use of YBCO in linear generators has a fundamental challenge that affects industrial production and material stability after prolonged use. This paper seeks to sustain the adoption of YBCO by improving its quality for linear generator applications. The yttrium cuprates modification (YBYbCO) was synthesized using the solid-state reaction technique by doping YBCO with ytterbium. The crystalline structure, microstructural pattern, and stability of the new sample were adequately measured and found to be structurally stable to ensure durability. It was reported that applying YBYbCO in the linear generator would lead to a 200% increase in energy generation. The higher number of particles and lower individual particulate resistance enable it to withstand chemical pressure, thereby prolonging the lifespan of the linear generator. [ABSTRACT FROM AUTHOR]

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Nickel Aluminum Bronze (NAB) alloys display characteristics like superior strength and excellent wear resistance. In this work, NAB was reinforced using various volume fractions of yttrium (Y2O3) and/or carbon nanotube (CNT) particles prepared using the Powder Metallurgy (PM) method. General full factorial design was used in MiniTab19 software. The experimental results showed a significant influence of the Y2O3 and CNT particles on mechanical and physical properties. The optimal results were recorded for the sample having 6 vol.% of Y2O3 and 1.5 vol.% of CNT. This sample exhibited the highest effect on characteristics with hardness value of 288 Hv, porosity of 10.2%, surface roughness of 0.15 µm, average particle size of 37.55 µm, wear rate of 0.0000313 g/mm, and friction coefficient of 0.68. The results demonstrated that there is an improvement of 64% in microhardness in comparison with the base alloy. Porosity, surface roughness, wear rate, friction coefficient, and average grain size were reduced by 4%, 81%, 71%, 31%, and 24%, respectively. [ABSTRACT FROM AUTHOR]

Neodymium-doped yttrium vanadate random lasers have presented exceptional efficiency and output power at the 1064 nm emission wavelength. However, emission at 1340 nm has not yet been observed for these random lasers, even though regular bulk lasers have presented many impressive properties in this infrared region. Here, we present a dual-emission Nd3+:YVO4 pellet random laser, which emits at both 1064 nm and 1340 nm using a 585 nm pump wavelength, showing a new property corresponding to a much lower laser threshold at 1340 nm than with 1064 nm. [ABSTRACT FROM AUTHOR]

The high creep strength and high radiation resistance of nanostructured ferritic alloys (NFAs) have been generally attributed to the high-density precipitation of (O, Y)-core nano-clusters and nano-oxides. In this work, the early-stage nucleation of (O, X)-core (X = La, Ce, and Hf) nano-clusters (NCs) with respect to (O, Y)-core NCs in multi-element micro-alloyed NFAs was investigated using first-principles calculations. Their competitive precipitation preference and possible growth sequence were predicted. The (O–O) pair was suggested as the most fundamental core of all types of NCs. Yttrium always has the strongest affinity with the (O–O) pairs to initiate the nucleation of NCs during the early-stage nucleation. Under the absence or depletion of yttrium, other types of (O, X)-core (X = La, Ce, Hf) structures could form, leading to different nucleation paths with the preference ordering of (O, La)-core > (O, Ce)-core > (O, Hf)-core. NC nucleation and composition in NFAs would, thus, strongly depend on the number availabilities of micro-alloying solute species in the neighborhood of the (O–O) pairs. [ABSTRACT FROM AUTHOR]

SiCf/SiC composites have emerged as one of the most promising materials for aero‐engine hot‐end structures. However, their performance is limited by their susceptibility to oxidation and corrosion reactions with oxygen and water vapor. To overcome this challenge, antioxidant‐modified phases are introduced into matrices of SiCf/SiC composites which improve their water and oxygen resistance. In this study, the resistance of SiCf/SiC composites modified by yttrium silicate matrix (SiCf/SiC‐YS composites) to air at 1000–1400°C and water‐oxygen environments at 1200°C was investigated. The diffusion paths of oxygen in SiCf/SiC‐YS composites and the antioxidant behavior of the yttrium silicate matrix were discussed. Additionally, the differences in oxygen and water‐oxygen corrosion resistance of SiCf/SiC‐YS composites at the same temperature were compared. The strength retention of SiCf/SiC‐YS composites after oxidation and water‐oxygen corrosion at 1200°C were 138.6% and 108.8%, respectively. This indicates that the addition of water vapor accelerated the degradation of SiCf/SiC‐YS composites. By comparing with SiCf/SiC composites, it can be concluded that the modification of the yttrium silicate matrix considerably improved the oxidation resistance of SiCf/SiC composites. [ABSTRACT FROM AUTHOR]

Materials are needed to preferentially remove heavy metal pollutants from waste streams. Here, atomic scale simulation, based on density functional theory, is used to predict encapsulation energies and electronic structures of the one-dimensional yttrium silicide electride (Y5Si3:e–) hosting the heavy metals such as zinc (Zn), cadmium (Cd), mercury (Hg), chromium (Cr), nickel (Ni), copper (Cu), or lead (Pb). Assuming that the metals are present as dimers in gaseous waste, encapsulation is highly exoergic for those metals with incomplete p or d electrons (Cr, Ni, Cu, and Pb). Of the heavy metals with complete d shells (Zn, Cd, and Hg), only Zn exhibits strong encapsulation. Differences in encapsulation behavior are analyzed in terms of electronic structures, electron affinities, atomic radii, and Bader charges. [ABSTRACT FROM AUTHOR]

Materials are needed to preferentially remove heavy metal pollutants from waste streams. Here, atomic scale simulation, based on density functional theory, is used to predict encapsulation energies and electronic structures of the one-dimensional yttrium silicide electride (Y5Si3:e–) hosting the heavy metals such as zinc (Zn), cadmium (Cd), mercury (Hg), chromium (Cr), nickel (Ni), copper (Cu), or lead (Pb). Assuming that the metals are present as dimers in gaseous waste, encapsulation is highly exoergic for those metals with incomplete p or d electrons (Cr, Ni, Cu, and Pb). Of the heavy metals with complete d shells (Zn, Cd, and Hg), only Zn exhibits strong encapsulation. Differences in encapsulation behavior are analyzed in terms of electronic structures, electron affinities, atomic radii, and Bader charges. [ABSTRACT FROM AUTHOR]

Niobium (Nb) is considered as candidate material for heat pipe in space nuclear reactors due to high melting point, low density, excellent compatibility with alkali liquid metals, irradiation resistance, workability and welding performance, but low strength restricts it's engineering application. In this work, yttrium (Y) was introduced into Nb matrix to achieve solution strengthening from Y atoms and dispersion strengthening from yttrium oxides. The latter one was realized by oxygen carrier route and vacuum electromagnetic levitation melting technique. Finally, one Nb521 (Nb-5.0 wt%W-1.7 wt%Mo-1.0 wt%Zr-0.07 wt%C) and four kinds of Nb521-xY (x = 0.1, 0.2 0.3 and 0.4 wt%) alloys were prepared. TEM characterization indicated that 80 nm Y2O3 particles were formed in Nb521-0.1Y, which exhibited the highest yield strength of 673 MPa, ultimate tensile strength of 740 MPa as well as larger elongation of 12.8%. Moreover, the solution strengthening of Y atoms and Orowan strengthening of yttrium oxides were evaluated quantitatively.

Mutual separation of Y(III) and Sr(II) from their waste solution has been an emerging research domain due to their various industrial applications. In this investigation, we emphasize the feasibility of selective separation of Y(III) from Sr(II) present in nitric acid medium using undiluted cyphos nitrate ionic liquid (IL): trihexyl(tetradecyl)phosphonium nitrate ([P66614][NO3]) as the ligating phase. The set experimental parameters were the feed phase acidity, initial nitrate ion concentration, initial feed metal ion concentration, equilibration time and temperature to unveil the efficacy of the proposed system. Efficient extraction of Y(III) selectively in presence of Sr(II) using only a salting agent in aqueous phase without additional extractant in IL phase was highlighted. A remarkable separation factor (SF) obtained for Y(III) over Sr(II) explored the efficacy of the proposed IL system. Y(III) loading in IL phase both in unirradiated and irradiated conditions was compared to evaluate the coordination behavior of irradiated moieties. In addition, a most important advantage of the proposed system is that it employs Milli‐Q water for the back extraction (stripping) of the loaded Y(III) from IL phase and does not demand any complexing agent (water soluble). This undoubtedly corroborates the economic and environmental benefits of the proposed IL system. [ABSTRACT FROM AUTHOR]

This study systematically investigated the influence of varying yttrium(Y) additions on the interfacial reaction mechanism between the DD5 superalloy melt and Al 2 O 3 -based ceramic molds during directional solidification. The analysis revealed the formation of a complex multilayer reaction layer at the alloy-ceramic interface. The interfacial products changed from CaO·6Al 2 O 3 to a mixture of various yttrium oxides after Y was added. As the reaction time increased, the sequence of interfacial reaction products observed on the surface of Y-containing alloys progressed as follows: Y 2 O 3 , Y 4 Al 2 O 9 , YAlO 3 , and ultimately Y 3 Al 5 O 12. Increasing the Y additions promoted the formation of a reaction layer with a higher atomic percentage of Y. The interfacial reaction process between the DD5 superalloy and Al 2 O 3 -based ceramic molds involved ceramic decomposition and diffusion, Y element diffusion and displacement reactions, Al 2 O 3 dissolution and further diffusion of the Al element. This process resulted in the formation of different yttrium-aluminum oxides and related to the bidirectional erosion of the Y 2 O 3. These interfacial reactions significantly contributed to the consumption of Y element within the alloy. • Components of multilayer interfacial reaction layer varied with the Y additions. • The phases and microstructures of Y 2 O 3 , Y 4 Al 2 O 9 , YAlO 3 , and Y 3 Al 5 O 12 , were determined. • Four oxidation reaction products formed sequentially with extended reaction time. • The reaction involved dissolution, diffusion, displacement and dual erosion. [ABSTRACT FROM AUTHOR]

Rare earth elements are an essential critical raw material in the development of modern technologies and are highly sensitive to both supply chain disruptions and market turbulence. The presented study examines the characteristics of fuel, fly ash, and bottom ash from lignite combustion in power plant units. Also, we attempted to determine the amount of amorphous glass in the ashes and whether and to what extent the glass from the ash samples is bound to REY. The suitability of the ash was assessed as an alternative source of REY. The fuel and ash samples were acquired from power plants in Poland. The tests determined the fuel quality parameters, including the chemical and phase composition, of amorphous glass using ICP-MS and XRD methods, respectively. The study showed that all ash samples dissolved in 4% HF were enriched in REY. The efficiency of REY enrichment varied, and its presence in the residue samples was found to be in similar proportions compared to the raw sample. All ash residue samples were enriched in critical elements. The obtained values of the Coutl prospective coefficient allowed for the classification of some of the analyzed ashes and their residues after dissolution in 4% HF as prospective REY raw materials. [ABSTRACT FROM AUTHOR]

The aim of the work was to study the effect of the YAG: Cr ceramics' stoichiometry deviation on the optical properties and efficiency of valence conversion of Cr cations. YAG: Cr ceramic powders with deviations from stoichiometry ranging from 0.225 to −0.35 at % excess yttrium were synthesized by chemical precipitation. The optical and luminescent properties of YAG: Cr4+ ceramics, as well as the microstructure of the ceramics, were studied. It has been shown that small deviations from the stoichiometry of YAG: Cr (within 0.35 at %) do not have a significant effect on the optical transmission and microstructure of YAG: Cr3+ ceramics, but strongly affect some characteristics of YAG: Cr4+ ceramics. It was found that the presence of excess aluminum or yttrium cations in YAG: Cr4+ ceramics leads to a decrease in the concentration of Cr4+ and a deterioration in the conversion from Cr3+ to Cr4+. [ABSTRACT FROM AUTHOR]

AbstractA new ion-pairing HPLC method has been developed for the analytical separation of rare earth elements (REEs), utilizing the unique “diad-effect” of the lanthanides. A chemometric approach was used to optimize the separation process, examining the impact of mobile phase pH and ion-pairing reagent concentration on resolution and elution time. A triple gradient elution program was proposed, involving changes in the pH of the mobile phase from 3.5 to 4.5, the ion-pairing reagent concentration from 25 mM to 0.05 M, and the mobile phase complexing additive (hydroxyisobutyric acid) concentration from 0.05 M to 0.5 M. With the proposed method, all REEs, including pairs that are typically difficult to separate (Pr–Nd, Eu–Gd, and Dy–Y), were effectively separated in less than eight minutes. The method validation conducted following ICH guidelines showed accurate results, with an accuracy of 99–108% across a concentration range of 50–150% of the target concentration for REEs. It also exhibited good linearity (0.9998–0.9992) across a concentration range of 5–15 µg/mL for REEs and a detection limit of 0.27–0.98 µg/mL for the various species. The proposed HPLC method proved reliable and successfully separated a commercial sample of yttrium-group oxides. [ABSTRACT FROM AUTHOR]

The yttrium-doped Ni-Zn ferrite of Ni0.4Zn0.6YxFe2-xO4 (x = 0.0, 0.03, 0.06, 0.09 and 0.12) nanoparticles was routed through sol-gel to examine the structural and magnetic. XRD authorized the establishment of a single-phase spinal structure and it was noticed that crystallite size (20.14 nm - 35.18 nm), lattice constant (8.369 °A - 8.424 °A), jump lengths (LA is from 3.635 °A - 3.651 °A and LB is from 2.963 °A - 2.976 °A) and unit cell volume (591.86 °A3 to 599.29 °A3) were increased with yttrium substitution. The density and porosity of the samples considerably varied with yttrium substitution. FESEM confirmed the morphology of the samples and EDX spectrographs were estimated the elemental compositions. The saturation magnetization (29.19 - 19.89 emu/g), remanence (16.79 - 11.63 emu/g), coercivity (206 - 56 Oe) and magnetic moment (1.24 - 0.86 A-m²) were maintained the decrease trend with yttrium substitution. [ABSTRACT FROM AUTHOR]

We present an analysis of the relative abundance features of a number of chemical elements in the atmospheres of metal-rich () Galactic-field RR Lyrae variable stars and the kinematic characteristics of these stars. We have previously shown that the relative abundances of some elements: magnesium, silicon, calcium, and to a greater extent of titanium, as well as yttrium and scandium in such stars are lower than in most other types of stars bearing similar metallicity. It is found here that some of these metal-rich RR Lyrae stars also have very low relative abundances of sodium, aluminum, and nickel. The orbital parameters of all the metal-rich RR Lyrae variables studied in this paper are typical of the Galactic thin or thick disk objects, however, the unusual chemical composition let us to suggest a possible extragalactic origin for some of them. [ABSTRACT FROM AUTHOR]

Tetrahedral oxygenated groups with large highest occupied molecular orbital‐lowest unoccupied molecular orbital (H gaps such as [SO4] are beneficial for deep ultraviolet (DUV) transmission but usually make against generating sufficient birefringence due to the small polarizability anisotropy. Thus, it is extremely difficult to obtain DUV transmission and large birefringence simultaneously in the search for DUV birefringent materials in sulfates. Herein, two new ammonium‐rare earth metal sulfates, NH4Y(SO4)2·H2O and NH4YSO4F2, with DUV transmission are presented. Meanwhile, both exhibit greatly elevated birefringence through the involvement of NH4+ units, compared to Y2(SO4)3·8H2O. Their optical properties are further investigated by theoretical calculations, and the effect of the introduction of NH4+ into yttrium sulfate on optimizing the structures and properties is discussed. This work may provide a new perspective for further exploration of DUV birefringent materials in tetrahedral oxygenated group sulfates. [ABSTRACT FROM AUTHOR]