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In this study, the concentration of thirteen non-volatile elements in coal fly ash samples obtained from the Kangal coal-fired thermal power plant located in Sivas province of Turkey was determined using an energy dispersive X-ray fluorescence (EDXRF) spectrometer. Non-volatile elements in coal fly ash samples were analysed in three groups: major (Al, Si, and Ca), rare earth (Y, La, Ce, Pr, and Nd), and other trace elements (Ga, Rb, Mo, Ba, and Hf). The average concentrations of Ca, Si and Al were found as 22.8, 10.9 and 5.4%, respectively. The average concentrations of Pr, Y and, Nd were found as 23.9, 19.1 and 78.2, respectively. La and Ce were observed below the detection limit of 2 mg/kg, except for two samples. The average concentrations of Ga, Rb, Mo, Ba and Hf were found as 18.6, 51.1, 177.3, 993.5 and 3.9 mg/kg, respectively. According to the average values of enrichment factor estimated for elements analysed in fly ash samples, Mo is found extremely enriched while Ca and Hf are significantly enriched. [ABSTRACT FROM AUTHOR]

High-energy photons in space environments, such as X-rays, thermal neutrons, and gamma rays, can cause ionization in polymer materials, leading to covalent bond breakage and degradation reactions. These reactions result in effects such as embrittlement, loss of elasticity, flaking, softening and stickiness, loss of mechanical strength, and gas emission, which can cause temporary damage or permanent failure of aerospace materials or devices. Rare earth elements have excellent radiation resistance to neutrons, high-energy photons and gamma rays due to their high absorption cross sections and atomic numbers. The photoelectric effect, Compton effect and electron pair effect of rare earth elements are firstly introduced in this paper. Next, the domestic and international research progress on the radiation resistance of rare earth elements in polymer materials, including fibers, plastics, rubber, epoxy resins, polyvinyl alcohol (PVA), and chitosan are reviewed. The discussion covers the incorporation of rare earth elements through doping, nanomaterial formation, and organic salts, utilizing preparation techniques such as co-precipitation synthesis, copolymerization, blending and extrusion, and molding. Testing methods include cobalt irradiation, neutron radiation, Monte Carlo simulations, and MCNP program calculations for neutron shielding. Comparative results with heavy metal lead demonstrate that rare earth elements significantly enhance the radiation resistance of polymer materials. Given their non-toxic and lightweight advantages, rare earth elements are expected to replace heavy metals like lead in applications within the medical, nuclear, and aerospace industries. The paper also provides a forward-looking perspective on the development of rare earth-based radiation-resistant polymer composite shielding materials in space environments. [ABSTRACT FROM AUTHOR]

This research aimed to explore the influence of the rare-earth element La on the interface microstructure and mechanical properties of Al/steel bimetallic composites produced through liquid–solid casting. The addition of the rare earth element La refined the morphology of eutectic silicon and ensured its uniform and continuous distribution. The interface structure of the Al/steel bimetallic composite exhibited distinct layering, primarily comprising two layers. The first layer, termed reaction layer I, comprised Al5Fe2 and τ1-Al2Fe3Si3 phases. While the second layer, termed reaction layer II, consisted of Al13Fe4, τ5-Al7Fe2Si, and τ6-Al9Fe2Si2 phases. The addition of La did not alter the types of intermetallic compounds present in the Al/steel reaction layer. As the La content increased to 0.3%, there was a notable reduction in the average thickness of both reaction layers I and II, reaching a minimum. The presence of La effectively restrained the growth of intermetallic compounds within the reaction layer. Consequently, the shear strength of the Al/steel bimetallic sample exhibited an initial increase followed by a subsequent decrease with increasing La content. With the addition of 0.3% La, the shear strength of the sample peaked at 30.1 MPa, representing a 66% increase. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Chinese Society of Rare Earths is the property of Editorial Department of Journal of the Chinese Society of Rare Earths and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the association between exposure to rare earth elements and metabolic syndrome and its components will not only help physicians better assess health risks but also help prevent and control the occurrence and development of metabolic syndrome. Objective: This study aimed to investigate the association between rare earth elements (REEs) and metabolic syndrome (MetS). Methods: We used a cross-sectional design based on the baseline data of the Prospective Cohort Study of Chronic Diseases in Ethnic Minority Natural Population in Guangxi in China. Logistic regression and BKMR models were employed to evaluate the association between REEs and risk of MetS. Results: Although REEs were not significantly associated with MetS, certain elements such as La, Pr, and Nd were negatively associated with abdominal obesity, whereas Ce, Pr, Nd, and Dy were positively associated with hypertension. BKMR models suggested a U-shaped relationship between mixed REEs and MetS, with varying effects on abdominal obesity and high blood pressure. Conclusions: This study suggests that exposure to REEs may be associated with a reduced risk of abdominal obesity and an increased risk of high blood pressure. [ABSTRACT FROM AUTHOR]

The effects of rare earth elements (REEs) on the corrosion behavior of weathering steels under a simulated immersion environment and a real atmospheric environment have been investigated in this paper. Although the corrosion rate of the indoor accelerated corrosion experiment (0.01 mol/L NaHSO3) is much higher than that of the real atmospheric exposure experiment, the addition of REEs can highly improve the corrosion resistance of test steels under both conditions. The improvement of the corrosion resistance can be attributed to the quick transformation of γ‐FeOOH into α‐FeOOH and the accelerated formation of a stable rust layer by REEs. Furthermore, the segregation of the REE inner rust layer increases the density of the rust layer and prevents corrosive particles from eroding the matrix. REEs can also promote the segregation of Cu, Cr, and other alloying elements in the rust layer, thus blocking the cracks and holes and enabling the formation of a continuous rust layer with good adhesion. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Geoscientica Sinica is the property of Acta Geoscientica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Both lanthanide-containing and fluorine-containing nanomaterials present challenging targets for microbial biosynthesis because these elements are toxic to most bacteria. Here, we overcome these challenges by using an Antarctic Shewanella baltica strain that tolerates these elements and report the first biosynthesis of lanthanide-doped fluoride nanoparticles (NPs) from them. NaYF4 NPs doped with Er3+/Yb3+ are prototypical lanthanide-based upconverting nanoparticles (UCNPs) with upconverted luminescence at visible wavelengths under infrared excitation. However, their synthesis employs high precursor concentrations, organic solvents, and elevated temperatures. Microbial biosynthesis offers a greener alternative but has not been explored for these materials. Here, we harness an extremophile S. baltica strain to biosynthesize UCNPs at room temperature, based upon its high tolerance for fluoride and lanthanide ions and the observation that tolerance of lanthanides increased in the presence of fluoride. Our biosynthesis produces electron-dense nanostructures composed of Na, Y, F, Yb, and Er in the bacterial periplasm, adhered to the outer cell membrane, and dispersed extracellularly, which exhibited up-converted emission under 980 nm excitation. This suggests that extracellular or periplasmic mineralization of lanthanides as fluorides protects the bacteria from lanthanide toxicity. Subsequent heating both enhanced upconverted emission from UCNPs and allowed observation of their crystallinity in transmission electron microscopy (TEM). This work establishes the first biosynthesis of NaYF4:Yb: Er UCNPs, advancing both nanotechnology and biotechnology. Graphical Abstract

Taking TiCp/Al-5Cu-1.9Mg-0.9Mn composite materials reinforced with 0.27%（volume fraction）TiC particles as the matrix， the effects of different Sm element contents on the microstructure and mechanical properties of the composite material were investigated. The results show that the addition of the Sm element significantly refines the dendritic microstructure and facilitates the dissolution of the second phase during the solid solution treatment. Consequently， an increase in the density of precipitated phases， including T-Al20Cu2Mn3 and S'-Al2CuMg， was observed in the aged microstructure. When the Sm element content is high （0.3%， mass fraction， the same below）， the microstructure exhibits blocky insoluble rare earth-containing compounds. With the addition of the Sm， the composite materials show a gradual increase in yield strength at both room temperature and 250 ℃. However， it will cause a decrease in plasticity. When the Sm element content is 0.3%， the yield strength at room temperature increases from 246 MPa to 310 MPa， and the yield strength at 250 ℃ increases from 191 MPa to 220 MPa. The analysis suggests that the increase in strength is attributed to the microstructural refinement and the increased density of precipitated phases induced by Sm. Conversely， the reduction in plasticity is attributed to the presence of coarse blocky insoluble rare earth compounds cutting through the matrix， leading to the easy generation of crack sources.

Abstract Background Gadolinium (Gd) is an increasingly found lanthanide element in soil; thus, understanding its impact on plant physiology, biochemistry, and molecular responses is crucial. Here, we aimed to provide a comprehensive understanding of Gd (150 mg kg− 1) impacts on guar (Cyamopsis tetragonoloba L.) plant yield and metabolism and whether the symbiotic relationship with arbuscular mycorrhizal fungi (AMF) can mitigate Gd toxicity of soil contamination. Results AMF treatment improved mineral nutrient uptake and seed yield by 38–41% under Gd stress compared to non-inoculated stressed plants. Metabolic analysis unveiled the defense mechanisms adopted by AMF-treated plants, revealing carbon and nitrogen metabolism adaptations to withstand Gd contamination. This included an increase in the synthesis of primary metabolites, such as total sugar (+ 39% compared to control), soluble sugars (+ 29%), starch (+ 30%), and some main amino acids like proline (+ 57%) and phenylalanine (+ 87%) in the seeds of AMF-treated plants grown under Gd contamination. Furthermore, fatty acid and organic acid profile changes were accompanied by the production of secondary metabolites, including tocopherols, polyamines, phenolic acids, flavones, and anthocyanins. Conclusions Overall, the coordinated synthesis of these compounds underscores the intricate regulatory mechanisms underlying plant-AMF interactions and highlights the potential of AMF to modulate plant secondary metabolism for enhanced Gd stress tolerance.

In recent years, the demand for rare earth elements has surged due to their unique characteristics and diverse applications. This investigation focuses on utilizing the rare earth element dysprosium oxide (Dy2O3) for the photocatalytic oxidation of model pollutants under solar light irradiation. A novel RGO-Dy2O3 nanocomposite photocatalyst was developed using a solvothermal approach, Dy2O3 nanorods uniformly deposited onto reduced graphene oxide (RGO) nanosheets. Comprehensive characterization techniques, including Brunner-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, high resolution – transmittance electron microscopy (HR-TEM), field emission–electron scanning microscopy (FE-SEM), atomic force microscopy (AFM), electron paramagnetic resonance spectroscopy (EPR), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy EIS techniques. The UV–visible diffusive reflectance spectroscopy (UV–Vis-DRS) studies revealed a band gap energy of 3.18 eV and a specific surface area of 114 m2/g for the fabricated RGO-Dy2O3 nanocomposite. The RGO-Dy2O3 nanocomposite demonstrated a high photocatalytic degradation efficiency of 98.1% at neutral pH for methylene blue (MB) dye for the dye concentration of 10 ppm. The remarkable photocatalytic performance was achieved within 60 min under solar light irradiation. Reusability tests demonstrated stability, maintaining over 90% photocatalytic efficiency after three cycles. The EPR spectra and quenching experiments confirmed that photogenerated hydroxyl radicals significantly influence the photodegradation processes. The RGO-Dy2O3 nanocomposite photocatalyst, with its green, easy preparation process and recycling capabilities, presents an ideal choice for various applications. It offers a viable alternative for the photocatalytic degradation of organic dyes in real wastewater, contributing to sustainable environmental remediation. [ABSTRACT FROM AUTHOR]

Both lanthanide-containing and fluorine-containing nanomaterials present challenging targets for microbial biosynthesis because these elements are toxic to most bacteria. Here, we overcome these challenges by using an Antarctic Shewanella baltica strain that tolerates these elements and report the first biosynthesis of lanthanide-doped fluoride nanoparticles (NPs) from them. NaYF4 NPs doped with Er3+/Yb3+ are prototypical lanthanide-based upconverting nanoparticles (UCNPs) with upconverted luminescence at visible wavelengths under infrared excitation. However, their synthesis employs high precursor concentrations, organic solvents, and elevated temperatures. Microbial biosynthesis offers a greener alternative but has not been explored for these materials. Here, we harness an extremophile S. baltica strain to biosynthesize UCNPs at room temperature, based upon its high tolerance for fluoride and lanthanide ions and the observation that tolerance of lanthanides increased in the presence of fluoride. Our biosynthesis produces electron-dense nanostructures composed of Na, Y, F, Yb, and Er in the bacterial periplasm, adhered to the outer cell membrane, and dispersed extracellularly, which exhibited up-converted emission under 980 nm excitation. This suggests that extracellular or periplasmic mineralization of lanthanides as fluorides protects the bacteria from lanthanide toxicity. Subsequent heating both enhanced upconverted emission from UCNPs and allowed observation of their crystallinity in transmission electron microscopy (TEM). This work establishes the first biosynthesis of NaYF4:Yb: Er UCNPs, advancing both nanotechnology and biotechnology. [ABSTRACT FROM AUTHOR]

In this paper, the effect of doping silicon with dysprosium (Dy) on its structural and optical characteristics is investigated. Silicon n-Si was doped with dysprosium by thermal diffusion at 1473 K for 50 h. Raman spectroscopy and X-ray diffraction analysis were used for the analysis. The Raman spectroscopy results showed a main peak at 523.93 cm-1, corresponding to n-Si optical phonons, with an increase in the intensity and full width at half maximum (FWHM) in n-Si samples, indicating an improvement in the crystallinity of the structure. A decrease in the intensity of the peaks at 127.16 cm-1 and 196.24 cm-1, associated with amorphous structures, confirms a decrease in defects. The detection of a new peak at 307.94 cm-1 indicates successful deposition of dysprosium as nanocrystallites associated with the 2TA phonon mode in the cubic phase of Dy2O3. X-ray diffraction analysis revealed characteristic structural lines indicating the (111) crystalline orientation and the presence of microdistortions in the lattice. Heat treatment and rapid cooling lead to a change in the intensity of structural lines, an increase in the second- and third-order lines, which indicates microstrains and a change in the size of subcrystallites. Doping of silicon with dysprosium improves the crystallinity of the structure, reduces the number of defects and forms polycrystalline layers on the surface consisting of SiO2 and Dy2O3 nanocrystals. [ABSTRACT FROM AUTHOR]

The characteristics of silicon MIS structures with ytterbium impurity are studied using non-stationary capacitance spectroscopy of deep levels. It is established that the presence of ytterbium atoms in the bulk of the silicon substrate leads to a shift in the capacitance-voltage characteristics towards positive bias voltages and a decrease in the density Nss of the surface states of the MIS structures. It is shown that this effect depends on the concentration of ytterbium atoms in the silicon substrate of the studied structures. In MIS structures based on Si, one deep level with an ionization energy Ec-0.32 eV is detected. [ABSTRACT FROM AUTHOR]

The location of the investigation area is in Oben Village, Nekamese District, Kupang Regency, East Nusa Tenggara Province with coordinates 123° 40'40” E - 123° 41'20” E and 10° 16'0” S - 10° 16'40” S. The geology of the study area is generally occupied by mixed rocks dominated by a gray clay, blackish brown, reddish brown, with foreign chunks consisting of peridotite, sedimentary rock consisting of brown and reddish reddish limestone, silt, micaceous sandstones, metamorphic rock: chlorite schist, with quartzite veins. Of the five samples analyzed, namely four samples of soil matrix and one sample of Peridotite, the following results were obtained: six rare earth elements were contained in 4 samples of the soil matrix, namely Yttrium (Y): 3.63 – 68.75 ppm, Praseudymium (Pr): 7.38 – 38.38 ppm, Scandium (Sc): 4.83 – 4.93 ppm, Lanthanum (La): 21.48 – 91.03 ppm, Cerium (Ce): 32.48 – 184.85 ppm, and Neodymium (Nd): 9.4 – 57 ppm specifically for sample 1 also contains 3 rare earth elements, namely: Gadolinium (Gd): 3.48 ppm concentration the average is lower than its abundance in nature, Samarium Sm: 13.1 ppm, and Dysprosium: (Dy): 6.88 ppm. For rock samples only contain Praseudymium (Pr): 7.78 ppm and Cerium (Ce): 87.88 ppm. [ABSTRACT FROM AUTHOR]

Over 30 small, discontinuous, tabular carbonatite bodies are located in the Sheep Creek area, Ravalli County, southwest Montana. The age and origin of these REE-Nb-rich deposits are currently being investigated. The purpose of this paper is to document the occurrence of several rare minerals, including daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite, in two of the carbonatite bodies. These minerals are found in association with monazite, hydroxylbastnäsite, ferriallanite, calcite, dolomite, baryte, quartz, actinolite, apatite, celsian, and Sr-rich aragonite. Automated SEM-EDS was used to target the areas of interest in polished specimens for more detailed spot SEM-EDS and electron probe microanalysis. Raman spectra were also acquired for each of the rare minerals. The complex mineralogy of the Sheep Creek carbonatites is most likely due to several overlapping thermal events, including primary magmatic, overprinting hydrothermal, and supergene weathering stages. The rare minerals described in this study are believed to be hydrothermal and/or carbothermal in origin, although no estimates of temperature are available at this time. [ABSTRACT FROM AUTHOR]

(Pyridine-2,5-diylbis(azaneylylidene)) bis-(methaneylylidene)) bis(benzene-5,1,3-triyl) tetrakis (hydrogen phosphonate) (PZMB) was successfully synthesized for Th(IV) and Ce(IV) adsorption, the adsorption parameters evaluated and found to be pH 3.5, time 60 min, dose 0.15 g. Adsorption kinetics, isotherm, and thermodynamics studies. Adsorption kinetics studies show that adsorbent follow pseudo-second-order model while isotherm studies conclude that adsorption processes fitted Langmuir and D-R isotherm model. The maximum adsorption capacity of BZMB of Th(IV) and Ce(IV) are 366.4 and 244.53 mg/g respectively, Thermodynamic studies indicate both adsorption processes exhibited by the PZMB were endothermic, spontaneous and sorption occurs in a random manner. [ABSTRACT FROM AUTHOR]

[Objective] The aims of this study are to investigate the sediment sources of slope erosion in production and construction projects, and to implement the targeted soil and water conservation measures to mitigate soil and water loss caused by human disturbance. [Methods] Indoor simulated rainfall tests combined with REE tracer technique were conducted to examine the erosion characteristics and contributions from different areas of engineering deposits with varying gravel contents [0 (pure soil), 10%, 20%, 30%] under the rainfall intensity of 90 mm/h. [Results (1) The amount of soil erosion of all areas of different gravel-containing engineering deposits was the largest in the down slope area, while the average erosion contribution of the down slope area (57.40%) was larger than that of the upper slope area and the middle slope area, which indicated that the down slope area was the main source of sediment. (2) The erosion contribution of the middle and down slope areas of the gravel-containing engineering deposits was significantly smaller than that of the pure soil deposits. The erosion contribution of the upper and middle slope areas of the gravel-containing engineering deposits was significantly greater than that of the pure soil deposits, and the erosion contribution of the down slope area of the gravel-containing engineering deposits was significantly less than that of the pure soil deposits. (3) The effect of gravel content on the amount and contribution of erosion at the down slope area was more significant (p<0.05). In the gravel-containing engineering deposits, the amount of erosion at the upper and down slope areas of the 20% gravel content engineering deposits was significantly greater than that of engineering deposits with 10% and 30% gravel contents. The contribution of erosion at the upper slope area of the engineering deposit with 10% gravel content was significantly greater than that engineering deposits with 20% and 30% gravel contents, and the contribution of erosion at the down slope area was significantly less than that engineering deposits with 20% and 30% gravel contents. [Conclusion] Among all the engineering deposits with gravel content, the erosion contribution rate of the down slope area is the largest, which indicates that the down slope area is the main source of sediment on the slope of the engineering deposits, and the protection and treatment of the down slope area should be strengthened. [ABSTRACT FROM AUTHOR]

Glass-based materials are renowned for their application prospects in neutron and gamma-ray shielding, focusing on their dual functionality of offering radiation protection while permitting visual monitoring. These materials stand out for their excellent chemical durability, resilience against radiation-induced deterioration, high refractive indices, and superior light transmission characteristics. In this paper, the initial sections are delved into the shielding mechanisms for neutron and gamma-ray radiation, employing Monte Carlo simulations to elucidate the design principles and development strategies of these shielding materials. It is complemented by a comprehensive review of the current state of research in glass-based shielding materials. Given the environmental and health concerns associated with lead-based glasses, lead glass is being abandoned. The paper highlights the predominance of silicate, borate, and borosilicate glasses in the industry. It is demonstrated that the addition of heavy metal oxides (such as Bi2O3 and BaO) and rare earth elements (like La and Gd) to the glass matrix can significantly increase the mass attenuation coefficient (MAC), reduce the half-value layer (HLV), and thereby enhance shielding effectiveness. Notably, the integration of these dopants may negatively impact the mechanical properties of materials. This paper also includes a comparison of glass-based shielding materials with alternative shielding solutions. Enhancing the multifaceted performance of glass-based shielding materials, alongside the advancement of ecofriendly and smart shielding solutions, will constitute a pivotal area of future research. [ABSTRACT FROM AUTHOR]

The small muddy areas developed in the southern Shandong Peninsula have attracted increasing attention from researchers because of complex changes in sediment sources driven by sea-level fluctuations and land-sea interactions since the late Pleistocene. This study investigates the evolution of sediment sources and their responses to environmental changes since the late Pleistocene, using core WHZK01 collected from the nearshore muddy area in southern Weihai for rare earth element (REE) analysis. In doing so, this work highlights the changing patterns of material sources and the primary control factors. The results reveal that the sedimentary deposits in core WHZK01 exhibit distinct terrestrial characteristics. Discriminant function analysis (FD) and source discrimination diagrams both suggest that the primary sources of these deposits are the Yellow River and adjacent small and medium-sized rivers, although the sources vary among different sedimentary units. Furthermore, the DU3 layer (17.82–25.10 m) displays typical riverine sedimentation, dominated by terrestrial detrital input, primarily from the local rivers, namely the Huanglei and Muzhu Rivers. The material in the DU2 layer (14.91–17.82 m) is mainly influenced by a mixture of the Qinglong and Yellow Rivers. The DU1 layer (0–14.91 m) is influenced by sea-level changes during the Holocene, with the Yellow River being the primary source, although there is also some input from local rivers. The changes in sea level during the Holocene and the input of Yellow River material carried by the coastal currents of the Yellow Sea are identified as the main controlling factors for the changes in material sources in the study area since the late Pleistocene, with small and medium-sized rivers also exerting some influence on the material sources. The above mentioned findings not only contribute to a better understanding of the source-sink systems of the Yellow River and adjacent small and medium-sized rivers but also deepen our understanding of the late Quaternary land-sea interactions in the Shandong Peninsula. [ABSTRACT FROM AUTHOR]

In view of the phenomenon that irregular inclusions are easy to use as crack sources, rare earth H13 steel with different gradients is designed. The results showed that ellipsoidal rare earth inclusions (Ce2O3, CeAlO3 and Ce2O2S) were formed from irregular Al2O3 inclusions with the assistance of rare earths. The carbides that precipitated from liquid phases were arranged in a network along the grain boundary, forming composite carbides that are rich in Mo and V. Along the grain boundary, the morphology of the composite carbides got finer, and MC-type carbides enclosed the modified inclusions into nuclei, facilitating their precipitation. After annealing, the microstructure revealed that the carbides were dispersed in black segregated patches along the grain boundary and were discontinuous. The average diameter of carbides decreased from 109.7 to 79.2 nm in the same region according to a statistical comparison of the number of carbides before and after the addition of rare earth elements. The carbides were distributed alongside primary carbides as tiny particles of M7C3 and M23C6 secondary carbides. Especially when the rare earth content was 0.032 wt-%, the impact toughness increased to 34%. This work offers a reference value for the practical application of rare earth in hot work die steel in addition to revealing the strengthening mechanism of ultra-high strength RE-13 steel. [ABSTRACT FROM AUTHOR]

Background: Gadolinium (Gd) is an increasingly found lanthanide element in soil; thus, understanding its impact on plant physiology, biochemistry, and molecular responses is crucial. Here, we aimed to provide a comprehensive understanding of Gd (150 mg kg− 1) impacts on guar (Cyamopsis tetragonoloba L.) plant yield and metabolism and whether the symbiotic relationship with arbuscular mycorrhizal fungi (AMF) can mitigate Gd toxicity of soil contamination. Results: AMF treatment improved mineral nutrient uptake and seed yield by 38–41% under Gd stress compared to non-inoculated stressed plants. Metabolic analysis unveiled the defense mechanisms adopted by AMF-treated plants, revealing carbon and nitrogen metabolism adaptations to withstand Gd contamination. This included an increase in the synthesis of primary metabolites, such as total sugar (+ 39% compared to control), soluble sugars (+ 29%), starch (+ 30%), and some main amino acids like proline (+ 57%) and phenylalanine (+ 87%) in the seeds of AMF-treated plants grown under Gd contamination. Furthermore, fatty acid and organic acid profile changes were accompanied by the production of secondary metabolites, including tocopherols, polyamines, phenolic acids, flavones, and anthocyanins. Conclusions: Overall, the coordinated synthesis of these compounds underscores the intricate regulatory mechanisms underlying plant-AMF interactions and highlights the potential of AMF to modulate plant secondary metabolism for enhanced Gd stress tolerance. [ABSTRACT FROM AUTHOR]

While rare earth elements (REEs) are essential for modern technology, their production methods raise concerns for agriculture. Researchers are now exploring ways to control and recycle REEs pollution, aiming to minimize agricultural impacts and potentially even develop methods to utilize these elements for improved crop yields. Regarding this issue, a new type of pillar[5]arene polymer (Pol‐P[5]‐BTZP) has been designed and synthesized by click reaction to enhance the efficiency of adsorption and recovery of rare earth metals. This polymer incorporates the unique structure of 2,6‐di‐1,2,3‐triazolyl‐pyridine. The results of various analyses revealed that Pol‐P[5]‐BTZP exhibits excellent thermal stability, a high specific surface area, and well‐distributed networks of micropores and mesoporous structures. The adsorption capacity of Pol‐P[5]‐BTZP for Tm3+, a representative REE, was evaluated using the Langmuir and Freundlich isothermal adsorption models with a maximum adsorption capacity (Qmax) of 127.71 mg/g. Furthermore, the versatility of Pol‐P[5]‐BTZP in adsorption and recovering various REEs was tested. In addition to its adsorption capabilities, the potential of Pol‐P[5]‐BTZP for rare earth recovery and reuse was assessed through experiments on the impact of Tm3+ and La3+ on seed germination. These experiments demonstrated the wide‐ranging applicability of Pol‐P[5]‐BTZP in recovering and reusing REEs for green agriculture. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The development of low‐cost transition metal compounds with high‐performance for efficient oxygen evolution reaction (OER) is of great significance in promoting the development of electrocatalysis. In this study, a Ce‐doped Ni3S4 catalyst (Ce0.2−Ni3S4) was synthesized through a one‐step solvothermal method, where the doped rare earth element Ce induced the transformation of NiS to Ni3S4. The Ce0.2−Ni3S4 catalyst exhibited excellent OER performance in 1 M KOH. At a current density of 10 mA cm−2, it showed a low overpotential of 230 mV and a low Tafel slope of 52.39 mV dec−1. Long‐term OER tests at the same potential lasted for 24 h without significant loss of current density. This work introduces a novel method of Ce element doping for modifying transition metal sulfides, providing new insights into the effective utilization of rare earth elements in the field of electrochemistry. It creates more chances for the progress of highly efficient catalysts for efficient OER, contributing to the advancement of electrocatalysis. [ABSTRACT FROM AUTHOR]

Türkiye is one of the most tectonically active regions in the world. Diyarbakır, which was chosen as the study area, is located in the south-eastern Anatolian region of Türkiye and also in the south of the Bitlis-Zagros Suture Zone (BZSZ). Some of the geothermal resources in Diyarbakır are actively exploited. The temperature of Çermik geothermal waters was recorded at 40–51 °C by MTA (General Directorate of Mineral Research and Exploration) between 2010 and 2014. However, subsequent measurements conducted following the Kahramanmaraş earthquake (Mw: 7.7 on 6 February 2023) revealed that the surface temperature of geothermal fluids had increased to between 52 and 56 °C. Previous studies have indicated that there are also many abandoned oil wells in the region where the wellhead temperatures are around 107 °C. As a result of hydrogeochemical analyses, deep circulating geothermal waters such as Çermik have Na-HCO3 composition, while shallow circulating and mixed cold surface waters such as Çınar, Bismil and Sur have Na-Ca-Cl-HCO3 composition. According to the chalcedony geothermometer results, the reservoir temperatures in the study area vary between 90 °C and 173 °C. REY (Rare Earth Elements and Yttrium) results show that geothermal fluids in the study area have negative cerium (Ce), europium (Eu) and yttrium (Y) anomalies. The negative Ce anomaly indicates that the colder aquifers are close to oxygen-rich surface waters and thermal fluids interact with Karacadağ volcanic rocks. Eu anomalies in groundwater are controlled by preferential mobilisation of Eu2+ during water-rock interaction compared to Eu3+, and negative Eu anomalies indicate leakage of geothermal fluids from granites. The Y/Ho values of the thermal fluids in the study area are between 30 and 40. This value is due to the active contribution of fluorine during the mobilisation of REY as a fluoride or fluorocarbonate ligand complex, causing Y to behave as a heavy pseudolanthanide. δ18O and δ2H isotope values show that the geothermal waters in the study area are of meteoric origin. The obtained results reveal that Diyarbakir province has a geothermal potential and usage potential can be increased by using the abandoned oil wells. [ABSTRACT FROM AUTHOR]

The Yili and Tuha Basins on the Tianshan Orogenic belt are important sandstone type uranium mineral areas in China. The Baxiankou area located in the Tuha Basin is an important area for uranium exploration in recent years, but uranium mineralization here is characterized by narrow ore belts, small thickness, low grade, and high calcium content. The study of trace element geochemical changes in Baxiankou area is weak, which restricts the analysis of the genesis of mineralization scale. Based on the study of the spatial zoning of oxidation fluid alteration, the quantitative migration and enrichment of trace element distribution patterns and characteristic elements in different alteration zones were carried out. Through comparison with the Mengqigur deposit in Yili Basin, the enrichment process and origin of uranium enrichment scale under the action of oxidation fluid in the Baxiankou area were revealed. The results show that the synchronous enrichment of variable valence elements such as U and Re within the mineralization zone indicates that oxidation-reduction is the main mineralization process. The enrichment of non volatile elements such as Sc, Co, Ni, Th, and REE in the oxidation zone and the depletion in the ore zone are related to the properties of groundwater. The hydrolysis and clay formation caused by high salinity groundwater enhance the adsorption of ions in the solution by debris particles in the oxidation zone. Since Pliocene, the rapid uplift of Tianshan Mountains caused the extreme arid climate in Tuha Basin, resulting in the redistribution of trace elements and rare earth elements in different alteration zones. In the analysis of the genesis of uranium mineralization, it is necessary to strengthen the characterization of the changes in valence and constant valence elements, and pay more attention to the ancient climate during the infiltration stage of the oxidation zone during the ore exploration process. [ABSTRACT FROM AUTHOR]

The rare metal and rare earth mineral resources in the eastern section of the north margin of North China Plate are distributed mainly in the plate margin or tectonic junction of different ages, controlled by regional major faults, such as Tancheng-Lujiang fault belt and Suolun-Xilamulun-Changchun-Yanji fault zone, and experienced mainly three stages of tectono-magmatic events including Lyuliangian, Indosinian and Yanshanian. The rare metal-rare earth minerals in the area are closely related to Mesoproterozoic and Mesozoic magmatic rocks. Over 10 rare metal-rare earth deposits or ore occurrences have been found so far, distributed mainly in Liaoning Province and eastern Inner Mongolia, dominated by metallogenesis of alkaline granite-alkali rock type, followed by pegmatite type. The mineralization of rare metal-rare earth elements is related to alkaline magmatism. The geochronology of ore-forming rock mass shows that the mineralization can be divided into three stages:Yanshanian (120-140 Ma), Indosinian (200-230 Ma) and Lyuliangian(2500-2510 Ma). The enrichment and mineralization process of rare metal-rare earth elements is closely related to the advanced evolution of alkaline magma. Under the action of water and volatiles, the magma experienced strong fractional crystallization, resulting in migration and accumulation of ore-forming elements. With the change of mineralization conditions such as temperature and pressure, the ore-bearing fluids were concentrated and mineralized in the late stage of magmatism with the crystallization of major rock-forming minerals. [ABSTRACT FROM AUTHOR]

The metal Gadolinium (Gd) is a member of the lanthanide (Ln) group and is recognized as an emerging pollutant due to its widespread application in modern technology. Its acute toxicity depends on its free ion concentrations (Gd3 +), which is directly related to chemical speciation. The Biotic Ligand Model (BLM) is a valuable tool for risk assessment which predicts the metal bioavailability and toxicity to specific organisms. However, studies developing BLM for any Ln species are rare. Consequently, this study aimed to develop a kinetic BLM to predict the acute toxicity of Gd to the freshwater crustacean Daphnia magna. A series of 48-hour toxicity tests were conducted using different major cation concentrations, in order to estimate their affinity constants for the biotic ligand (BL). The model was then validated, first in the presence of dissolved organic matter (DOM), and then with water samples collected from lakes, rivers, and estuaries in France and Germany. The outcome revealed that three major cations (potassium, magnesium, and calcium) act as strong competitors. The model was successfully validated in the presence of organic matter and in the majority of surface freshwater samples (9 out of 13 samples). In this case, the predicted survival had a strong fit with the observed data. However, this was reduced when applying the model to samples of elevated electroconductivity and a pH below 6.8, when survival was consistently overestimated, potentially a multistressor effect. The kinetic BLM predicted 48 h measured EC50 ranging from 4 to 30 mg L−1 which agreed with the data from the literature. The model could also predict chronic effect of Gd by estimating the no-effect concentration (NEC) under prolonged exposure time ranging from 0.1 to 1 mg L−1.

In this paper, the effect of doping silicon with dysprosium (Dy) on its structural and optical characteristics is investigated. Silicon n-Si was doped with dysprosium by thermal diffusion at 1473 K for 50 h. Raman spectroscopy and X-ray diffraction analysis were used for the analysis. The Raman spectroscopy results showed a main peak at 523.93 cm⁻¹, corresponding to n-Si optical phonons, with an increase in the intensity and full width at half maximum (FWHM) in n-Si samples, indicating an improvement in the crystallinity of the structure. A decrease in the intensity of the peaks at 127.16 cm⁻¹ and 196.24 cm⁻¹, associated with amorphous structures, confirms a decrease in defects. The detection of a new peak at 307.94 cm⁻¹ indicates successful deposition of dysprosium as nanocrystallites associated with the 2TA phonon mode in the cubic phase of Dy2O3. X-ray diffraction analysis revealed characteristic structural lines indicating the (111) crystalline orientation and the presence of microdistortions in the lattice. Heat treatment and rapid cooling lead to a change in the intensity of structural lines, an increase in the second- and third-order lines, which indicates microstrains and a change in the size of subcrystallites. Doping of silicon with dysprosium improves the crystallinity of the structure, reduces the number of defects and forms polycrystalline layers on the surface consisting of SiO2 and Dy2O3 nanocrystals.

The characteristics of silicon MIS structures with ytterbium impurity are studied using non-stationary capacitance spectroscopy of deep levels. It is established that the presence of ytterbium atoms in the bulk of the silicon substrate leads to a shift in the capacitance-voltage characteristics towards positive bias voltages and a decrease in the density Nss of the surface states of the MIS structures. It is shown that this effect depends on the concentration of ytterbium atoms in the silicon substrate of the studied structures. In MIS structures based on Si, one deep level with an ionization energy Ec-0.32 eV is detected.

With the increasing global demand for rare earth elements and the depletion of traditional mineral resources, recycling rare earth elements from industrial solid waste has become an important direction of sustainable resource utilization. Phosphogypsum is a kind of industrial by-product with huge output and trace rare earth elements, its effective treatment and resource utilization are of great significance for environmental protection and economic development. Based on the occurrence state of rare earth elements in phosphogypsum, the research progress of leaching of rare earth elements in phosphogypsum was reviewed in this paper. The leaching mechanism and influencing factors of different leaching agents were summarized and analyzed.

Abstract This research delves into the intricate nexus of particle size, mineralogical composition, surface attributes, elemental mapping, and rare earth element (REE) adsorption mechanisms within an ion-adsorption clay sample from South America. The investigation entails the fractionation of the ion-adsorption clay into three size categories: S1 (