Search Results (1,255)

Local pier scour remains one of the leading causes of bridge failure, calling for predictions that are both accurate and uncertainty-aware. This study develops an interpretable data-driven framework that couples CatBoost (Categorial Gradient Boosting) for deterministic point prediction with NGBoost (Natural Gradient Boosting) for probabilistic prediction. Both models are trained on a laboratory dataset of 552 measurements of local scour at bridge piers using non-dimensional inputs (y/b, V/V_c, b/d₅₀, Fr). Model performance was quantitatively evaluated using standard regression metrics, and interpretability was provided through SHAP (Shapley Additive Explanations) analysis. Monte Carlo–based reliability analysis linked the predicted scour depths to a reliability index β and exceedance probability through a simple multiplicative correction factor. On the held-out test set, CatBoost offers slightly higher point-prediction accuracy, while NGBoost yields well-calibrated prediction intervals with empirical coverages close to the nominal 68% and 95% levels. This framework delivers accurate, interpretable, and uncertainty-aware scour estimates for target-reliability, risk-informed bridge design. Full article

Magmatic zircon trace element compositions and their variation trends provide valuable insights into the nature and evolutionary processes of magmatic rocks. The Himalayan orogen contains widespread leucogranites. Despite extensive studies on these granites, the features and petrogenetic implications of trace element composition of zircons from the leucogranites remain poorly constrained. In this study, we present a comprehensive dataset comprising new cathodoluminescence (CL) images, U-Pb ages, and trace element compositions of zircons from the Himalayan leucogranites, and compare them to the previously reported trace element data of zircon from I-type granites. Our results show that zircons from the Himalayan leucogranites have high Hf, U, Y, P, Th, Sc, and heavy rare earth element contents (HREE), and low Nb, Ta, Ti, and light rare earth element contents (LREE), and can be divided into two types. Type I (low-U) zircons exhibit well-developed oscillatory zoning, and the U concentrations are mostly <5000 ppm. Type II (high-U) zircons display mottled or spongy textures and possess elevated U contents that are mostly >5000 ppm. Zircons from the Himalayan leucogranites have higher contents of U, Hf, Nb, Ta, and elevated U/Yb ratios, but lower Th/U, Eu/Eu*, Ce/Ce*, LREE/HREE, and Ce/U values than those from I-type granitic zircons. Furthermore, zircons in the Himalayan leucogranites have gradually decreasing Th, Ti, Th/U, Eu/Eu*, and Ce/Ce*, and increasing U, Nb, Ta, and (Yb/Gd)_N with increasing Hf. These geochemical features suggest the magmas involved in the genesis of leucogranites originated from the partial melting of metasedimentary sources under relatively reduced conditions, and underwent a high degree of magmatic fractionation. Full article

In order to meet the demand for new optical temperature-sensing materials with high sensitivity and a wide application temperature range, Yb³⁺/Er³⁺: CaYAlO₄ phosphor with excellent physical and chemical stability and thermal conductivity was studied for the first time. Yb³⁺/Er³⁺: CaYAlO₄ phosphors have been synthesized by the high-temperature solid-state method. Under 980 nm excitation, three characteristic emission bands peaking at 528, 549 and 665 nm were observed which are attributed to the transitions ²H_11/2, ⁴S_3/2 and ⁴F_9/2 to ⁴I_15/2, respectively. The temperature-sensing behaviors of the phosphor were investigated using the luminescence intensity ratio technique based on both the TCL (²H_11/2/⁴S_3/2) and NTCL (⁴F_9/2/⁴S_3/2, ²H_11/2/⁴F_9/2) model over a wide temperature range of 163–700 K. The maximum relative sensitivities of TCLs (²H_11/2/⁴S_3/2), NTCLs (⁴F_9/2/⁴S_3/2) and NTCLs (²H_11/2/⁴F_9/2) were 3.69% K⁻¹, 0.443% K⁻¹ and 3.86% K⁻¹ at 163 K, 275 K and 163 K, while the maximum absolute sensitivities were 4.04 × 10⁻³ K⁻¹, 15.2 × 10⁻³ K⁻¹ and 7.81 × 10⁻⁴ K⁻¹ at 499 K, 499 K and 247 K, respectively. Results suggest that Yb³⁺/Er³⁺: CaYAlO₄ phosphor is a promising temperature-measuring material with advanced optical sensing capabilities over a wide temperature range. Full article

Following a series of successful applications to the neighboring isotopic chains of the rare-earth region, a mean-field-derived IBM-1 Hamiltonian with an intrinsic triaxial deformation derived from fermionic proxy-SU(3) irreducible representations (irreps) is employed for the study of energies and $B\left(E2\right)$ transition strengths in the low-lying quadrupole bands of the even–even ^162–182Yb. Proxy-SU(3) next-highest-weight irreps are incorporated in the calculations for the first time, leading to a significantly improved agreement with experimental data, where available, compared to axially symmetric calculations, as well as to triaxial calculations considering only highest-weight irreps. Full article

The superconducting transition temperature, $T_c$, of the graphite intercalation compound, Ca${\mathrm{C}}_6$, was calculated using the Roeser–Huber (RH) formalism. This method was adapted to alloys with complex crystal structures by identifying symmetric paths for the superconducting charge carriers (Cooper pairs) and incorporating interactions with neighboring atoms through phonon coupling. The evaluation of the lowest energy levels, ${\Delta }_{\left(0\right)}$, along all relevant crystallographic directions reveals a slight anisotropy between the in-plane and out-of-plane directions, consistent with the experimental observation of the gap anisotropy by point contact spectroscopy. The $T_c$ values obtained for Ca${\mathrm{C}}_6$, Ca${\mathrm{C}}_6$ with applied high pressure, and Yb${\mathrm{C}}_6$ show good agreement with experimental data, thereby supporting both the validity of the RH approach and its predictive capability in describing superconductivity within complex crystal structures. Full article

The tectonic evolution of the Paleo-Asian Ocean during the Early to Middle Permian remains a key issue in understanding the geodynamic history of the Central Asian Orogenic Belt. To address this, we conducted petrological, whole-rock geochemical, zircon U–Pb geochronological, and Hf isotopic analyses of Early Permian biotite granodiorite and Middle Permian porphyritic granite from the south-central Great Xing’an Range. Zircon U–Pb dating yields ages of 273.2 ± 1.4 Ma and 264.4 ± 1.5 Ma, indicating that these intrusions emplaced during Early and Middle Permian. Geochemical analyses show that the rocks are characterized by high SiO₂ and Al₂O₃ contents, and low MgO and CaO contents and belong to the metaluminous to weakly peraluminous series, typical of I-type granites. The rocks are enriched in light rare earth elements and large-ion lithophile elements (e.g., Rb, Ba, K), but depleted in heavy rare earth elements and high field strength elements (e.g., Nb, Ta, P, Ti), with weakly negative Eu anomalies. The Early Permian pluton exhibits low-Sr and high-Yb characteristics and thus fall in the plagioclase stability field. In contrast, Middle Permian pluton was derived from magmas generated by partial melting under high-pressure conditions and that, underwent crystal fractionation during ascent to the mid-upper crust, ultimately forming low-Sr and low-Yb type granites. All zircon ε_Hf(t) values are positive (+4.84 to +14.87), with the corresponding two-stage Hf model ages ranging from 345 Ma to 980 Ma, indicating that the magmas were predominantly derived from juvenile crustal materials accreted during the Neoproterozoic to Phanerozoic. Considering these results, we propose that the Paleo-Asian Oceanic plate continued to subduct beneath the Songliao–Xilinhot block to the north during the Early to Middle Permian, with intense subduction and crustal thickening occurring in the Middle Permian. This suggests that the south-central segment of the Great Xing’an Range was situated in an active continental marginal setting during the Early-Middle Permian. Full article

Mesozoic granitic rocks are widely developed in the Great Xing’an Range, and determining their emplacement age and genesis is crucial for reconstructing the tectonic-magmatic evolution of Northeast China. This paper reports the petrographic, geochronological, geochemical and zircon Hf isotopic characteristics of granites in the Huolin Gol area of the southern Great Xing’an Range to determine the formation age, source nature and geodynamic background of the rocks in this area. Zircon U–Pb dating results show that the granites in the study area were formed in the Early Cretaceous (134–130 Ma), rather than the Late Jurassic as previously thought. The granites have SiO₂ contents ranging from 75.02 to 78.53 wt.%, Na₂O = 3.55–3.89 wt.%, K₂O = 3.98–5.11 wt.%, Na₂O/K₂O = 0.72–0.97, A/CNK = 1.04–1.14. Their rare earth element (REE) distribution patterns are all right-inclined, with LREE/HREE = 3.89–12.41, (La/Yb)_N = 2.39–18.86, Eu/Eu* = 0.02–0.17. Trace element spider diagrams show significant enrichment in Rb, Th, U, K, Pb and LREEs, and depletion in Ba, Nb, Ta, Sr, P, Ti and HREEs. The zircon εHf(t) values range from +6.4 to +15.0, and the two-stage Hf model ages (T_DM2) range from 773 to 226 Ma. These characteristics indicate that the granitic rocks belong to the weakly peraluminous high-K calc-alkaline I-type granite, derived from partial melting of newly generated juvenile continental crust materials. Combined with the coeval magmatic associations, spatial distribution patterns, and regional tectonic evolution, we propose that the Early Cretaceous granitic rocks in the study area formed in an active continental margin setting, with their geodynamic mechanism linked to the subduction of the Paleo-Pacific Plate beneath the East Asian continent. Full article

In this study, a surface treatment of Ti grade 1 was carried out in air with the use of a Yb-fiber laser to increase the friction-wear properties tested in dry contact with α-Al₂O₃. The laser surface treated specimens clearly differ in their surface roughness and wettability, coefficient of friction and resistance to wear, compared to untreated specimens. The microstructure changes induced by laser treatment were investigated using confocal scanning electron microscopy with chemical composition analysis by energy-dispersive spectroscopy, and phase composition by X-ray spectroscopy. It was found that laser surface treatment caused the formation of titanium oxide layers with TiO₂ (rutile, anatase and brookite) as the main constituent, while in the subsurface areas a partial transformation of α-Ti to β-Ti or α′-Ti was thermally induced. Specimens containing β-Ti or α′-Ti in the subsurface area and anatase or brookite in the top layer were characterized by two times lower friction coefficient values and 10 times lower volume wear index Wv in comparison to untreated Ti grade 1. Results clearly confirmed the beneficial effect of laser surface treatment on friction-wear properties of Ti grade 1, but the selection of laser processing parameters was crucial both for resistance to abrasive wear and wettability. Full article

We demonstrate a compact astro-comb with ~30 GHz line spacing covering the 560–900 nm range, seeded by a 1 GHz Yb:fiber laser frequency comb phase-locked to a rubidium clock for long-term frequency stability. The comb spacing is multiplied by a passively stabilized Fabry–Pérot cavity, which is vacuum-sealed (3.3 × 10⁻⁵ Pa) and temperature-controlled at 25 ± 0.05 °C, exhibiting a resonance linewidth of 80.56 MHz. Characterization using a high-resolution Fourier-transform spectrometer reveals sharp, evenly spaced comb lines with a maximum side-mode suppression ratio of 23.86 dB. The estimated radial velocity (RV) precision reaches ~63 cm/s, and further reduction in measurement noise is expected to achieve <10 cm/s precision, meeting the stringent requirements of next-generation astronomical spectrographs. Full article

KY₃F₁₀:Yb³⁺, Tm³⁺ upconversion microparticles (UCMPs) with varying Mn²⁺ doping concentrations were synthesized via a hydrothermal method. Under 980 nm laser excitation, the sample with 3 mol% Mn²⁺ doping demonstrated markedly enhanced luminescence performance, exhibiting a significant intensity increase compared to undoped samples. The as-synthesized UCMPs were successfully incorporated into an anti-counterfeiting ink. Target information was encrypted using a hash function to generate a QR code, which was then screen-printed onto substrate materials. Under 980 nm laser irradiation, the printed QR code exhibited visible blue fluorescence with high stability, confirming its anti-counterfeiting capability. Furthermore, an image recognition system for anti-counterfeiting, based on a hybrid Convolutional Neural Network-Bidirectional Long Short-Term Memory (CNN-BiLSTM) architecture, was developed on the Matlab platform. The system achieved 100% recognition accuracy for the luminescent QR code patterns, providing valuable insights for the development of deep learning-based image anti-counterfeiting technologies. Full article

Zero-dimensional (0D) rare-earth-based metal halides show great potential in photonic and optoelectronic applications owing to their high stability, strong exciton confinement, and tunable energy levels. However, the weak absorption and narrow 4f-4f transitions of rare-earth ions limit their performance. To address this, a series of Sb³⁺-doped Cs₃LnCl₆ (Ln: Yb, La, Eu, Ho, Ce, Er, Tb, Sm, Y) nanocrystals were synthesized via a hot-injection method to study the role of Sb³⁺ doping. Sb³⁺ incorporation induces strong broadband self-trapped exciton (STE) emission from Jahn–Teller-distorted [SbCl₆]³⁻ units and enables efficient energy transfer from STEs to rare-earth ions. As a result, the photoluminescence intensity and spectral tunability are improved, accompanied by bandgap narrowing and enhanced light absorption. Different lanthanide hosts exhibit distinct luminescence behaviors: La-based materials show dominant STE emission, while Tb-, Er-, Yb-, Ho-, and Sm-based systems display STE-mediated energy transfer and enhanced f-f emission. In Eu- and Ce-based hosts, unique mechanisms involving Eu²⁺/Eu³⁺ conversion and Ce³⁺ → STE energy transfer are observed. Moreover, composition-dependent emissions in Sb³⁺-doped Cs₃Tb/EuCl₆ enable a dual-mode color and spectral encoding strategy for optical anti-counterfeiting. This study highlights the versatile role of Sb³⁺ in tuning electronic structures and energy transfer, offering new insights for designing high-performance rare-earth halide materials for advanced optoelectronic applications. Full article

Fossil fuel overuse drives excessive CO₂ emissions, exacerbating environmental degradation and climate change. Coupling electrochemistry with microbial fermentation provides a promising route to convert CO₂ into fuels and chemicals. However, microbial electrolytic solution tolerance remains a critical bottleneck, as observed in model organisms like Saccharomyces cerevisiae (S. cerevisiae). To address this, we engineered S. cerevisiae to utilize electrochemically derived formate, thereby boosting free fatty acids (FFAs) production. By optimizing culture conditions and heterologously expressing formate dehydrogenase (FDH), we improved formate assimilation efficiency. Additionally, we introduced stress-resistant genes for a better electrolytic solution tolerance to sustain growth and FFAs synthesis under harsh electrolytic conditions (e.g., high formate/salt ion concentrations), eliminating the need to separate formate from the electrolyte post-electrolysis. In the presence of 4 g/L formate electrolytic medium, the engineered strain YB061 achieved a 41.9% increase in biomass and a formate conversion rate exceeding 97.0%. Compared to the parental strain, YB061 enhanced FFAs production by 92.8% by utilizing formate-containing electrolytes, demonstrating great potential for bio-electrochemical manufacturing. However, further work is needed to improve yeast tolerance to high formate concentrations and to enable direct coupling of CO₂ electroreduction with microbial cultivation. Full article

The NV center in diamonds has been widely employed in quantum sensing, quantum computing, and bioimaging due to its controllable ground-state spin, detectable magnetic resonance, excellent photostability, favorable biocompatibility, and chemical inertness. However, conventional excitation using 532 nm green light still exhibits certain limitations in practical applications. To address this, we propose a novel NV center excitation method based on the upconversion of near-infrared light to green emission. Through the synthesis of molybdenum-doped NaYF₄: 20% Yb³⁺, 1.5% Er³⁺ upconversion materials, efficient excitation of NV centers has been achieved. Both UC-LED luminescence spectroscopy and ODMR measurements confirm that the green light generated via the upconversion process exhibits sufficient intensity to effectively excite NV centers. Meanwhile, the characteristic sharp emission peaks of rare-earth upconversion materials eliminate the need for optical filters, facilitating device miniaturization, and a miniaturized UC-LED sensor has been developed. Full article

Ions of Gd³⁺ and Yb³⁺ have radii similar to those of Zr⁴⁺, enabling them to form limited solid solutions in the ZrO₂ lattice through substitution. After solid solution formation, oxygen vacancy defects and complex defect aggregates are generated, which are crucial for stabilizing the high-temperature phase structure and reducing thermal conductivity. Therefore, in this study, 8 wt% Y₂O₃ and 5 wt% Yb₂O₃ were doped with 5 wt%, 10 wt%, and 15 wt% Gd₂O₃, respectively, to stabilize zirconia powders. GYYZO thermal barrier coatings (TBCs) were fabricated via atmospheric plasma spraying (APS). Subsequently, the GYYZO coatings with different Gd₂O₃ addition amounts were subjected to continuous thermal shock cycling at 1100 °C for 10, 30, 60, 90, and 150 cycles. The results indicate that the incorporation of Gd₂O₃, Yb₂O₃, and Y₂O₃ leads to the formation of stable tetragonal ZrO₂ phase in the GYYZO coatings. Although increasing the Gd₂O₃ addition amount reduces the thermal conductivity of the coatings, excessive Gd₂O₃ addition causes coating spallation. The GYYZO coating with 10 wt% Gd₂O₃ exhibits the lowest thermal conductivity of 0.59 W/(m·K). Additionally, the GYYZO coating with 10 wt% Gd₂O₃ can withstand thermal cycling for 150 cycles, while the one with 5 wt% Gd₂O₃ can endure 90 of thermal cycles. In contrast, the 8YSZ coating cracks and spalls after 60 thermal cycles. These findings demonstrate that doping ZrO₂ with Gd₂O₃, Yb₂O₃, and Y₂O₃ can enhance the thermal cycling resistance of the coatings and effectively reduce their thermal conductivity, but excessive Gd₂O₃ addition will decrease the coating adhesion strength. Full article

Global climate change has profoundly affected agricultural ecosystems by altering the spatiotemporal patterns of temperature and precipitation, disrupting ecological equilibrium, and increasing environmental variability for crop growth, thereby posing significant challenges to food security. Based on 1 km-resolution gridded datasets of mean precipitation and temperature for Liaoning Province from 1950 to 2023, this study integrated the Miami and Thornthwaite Memorial models with climate tendency rate analysis, Mann–Kendall trend tests, and inverse distance weighting interpolation to assess spatiotemporal changes in climate potential productivity (CPP) and its relationship with grain yield dynamics. The results show that, from 1950 to 2023, annual precipitation exhibited a fluctuating downward trend (−8.5 mm/10a), while mean annual temperature increased significantly (0.3 °C/10a). Consequently, precipitation-based climatic production potential declined at a rate of 10.4 g·m⁻²·(10a)⁻¹, whereas temperature-based, evapotranspiration-based, and standard climate potential productivity (Yb) increased at rates of 23.3-, 6.6-, and 5.7 g·m⁻²·(10a)⁻¹, respectively. Spatially, CPP displayed a distinct gradient characterized by higher values in the southeast and lower values in the northwest, with a stronger correlation to precipitation than to temperature. Climate classification analysis indicated that warm-humid conditions enhanced CPP, whereas cold-dry, cold-humid, and warm-dry conditions reduced productivity. Although grain yield per unit area and climate resource utilization efficiency increased by 89.4 g·m⁻²·(10a)⁻¹ and 9.0% per decade, respectively, the yield-increasing potential declined by 84.1 g·m⁻²·(10a)⁻¹, indicating that while advances in agricultural technology have improved resource conversion efficiency, the potential for further yield gains through climate-dependent strategies alone is increasingly limited. Full article