Search Results (564)

The induced polarisation (IP) technique is a geophysical method used to measure chargeability and resistivity, providing crucial insights into subsurface geological structures. Traditionally, IP measurements have been instrumental in exploring disseminated sulphide deposits, leveraging the strong polarisation response of metallic particles. It provides valuable insights about rock mineralisation, matrix composition, and formation polarizability by analysing electrical parameters. However, their potential to predict metallurgical performance remains largely unexplored. This study evaluates whether IP parameters—chargeability and resistivity—can serve as geometallurgical indicators for copper sulphide ores. The evaluation integrates IP measurements with mineralogical and flotation data. Artificial pyrite–sand mixtures and five real ore samples from Mount Isa were analysed using the sample core IP tester and mineral liberation analysis, followed by collectorless flotation tests. Statistical analysis demonstrated a strong correlation between resistivity and chalcopyrite recovery (R² = 0.90, p = 0.99), as well as a moderate correlation between chargeability and chalcopyrite selectivity (R² = 0.72, p = 0.93). These findings demonstrate that IP captures key textural and electrochemical features governing flotation behaviour, including pyrite abundance, mineral liberation, and galvanic interactions. The results highlight IP as a promising rapid-assessment tool for identifying ore variability and forecasting flotation response, with potential integration into geometallurgical models and mine-to-mill optimisation. Further validation across broader ore domains is recommended to refine the predictive capability of IP-based indicators. Full article

The interpretation of geophysical multi-attribute surveys is often subjective and complicated by large datasets, prompting the need for automated fusion methods that preserve structures and enhance anomalies. This study introduces an image fusion approach that combines the non-subsampled contourlet transform (NSCT) with the New Metric Parameter (NMP) rule to integrate multi-source polarizability and resistivity data for copper–nickel exploration. Using NSCT, source images are decomposed into multi-scale, multi-directional low- and high-frequency sub-bands. Low-frequency components are fused through dynamic weighting, while high-frequency components are merged using the NMP rule. The sensitivity to key parameters—such as low-frequency weight, grid size, and grid angle—was assessed using field data. Results indicate that NSCT + NMP fusion enhances spatial resolution and boundary definition of anomalies, effectively merging low resistivity with high polarizability signals. Quantitative field validation shows that 82.43% of the gabbroic mineralization zone has a judging coefficient below 0.45, confirming the fusion accuracy. Optimal parameter choices include dynamically adjusted low-frequency weights, a grid size that balances detail and noise suppression, and a 45° square grid for directional neutrality. This method offers a practical strategy for joint multi-physical data analysis and improved spatial recognition of mineralized bodies in exploration. Full article

Oxide perovskites with simultaneously large band gaps and high-static dielectric constants are of considerable interest for advanced microelectronics, dielectric devices, and energy storage applications, yet their discovery remains challenging because electronic insulation, lattice polarizability, and thermodynamic accessibility are strongly coupled and often mutually competitive. Here, we develop a physics-guided multitask learning framework for the joint prediction of the band gap and static dielectric response in chemically constrained single-perovskite oxide ABO₃ compounds. To ensure data fidelity and physical comparability, the learning space is strictly restricted to simple oxide ABO₃ perovskites from the Materials Project, while mixed-fidelity band gaps, heterogeneous dielectric definitions, and chemically inconsistent samples are excluded. The model integrates role-aware A-/B-site descriptors, perovskite-specific geometric and structural features, multitask prediction of Eg, εtotal, εelectronic, and εionic, explicit physical consistency constraints, auxiliary candidate classification, ranking learning, and reliability-aware screening with uncertainty and out-of-distribution control. Under B-site-grouped cross-validation, the framework achieves 97.4% accuracy, Recall of 96.5%, and an F1 score of 96.1%, while maintaining robust transferability on the independent JARVIS validation set. The results show that high-gap/high-k candidates occupy a chemically non-random subspace governed by B-site-centered electronic–lattice coupling, and that physically consistent multitask learning substantially improves both predictive coherence and candidate enrichment. More broadly, this study establishes a data-consistent, physics-constrained, and transferable paradigm for the intelligent discovery of functional oxide dielectrics. Full article

In this study, we evaluated various density functional theory (DFT) methods to obtain thermodynamic parameters, such as enthalpy and Gibbs free energy, and compared them with experimental values obtained from conductometric analysis. As a model system, we chose the heptakis(2,6-di-O-methyl)-β-cyclodextrin (DIMEB) complex with the recently synthesized fluorinated compound, butane-1,4-diyl bis(2,2,2-trifluoroethane-1-sulfonate) (BFS). The analysis was carried out in the temperature range of 293.15–313.15 K. A conformational search was performed to identify the most stable complexes. The final stage of optimization was conducted at the ωB97X-D4/6-31G(d,p) level of theory in the presence of water, modeled using the conductor-like polarizable continuum model (CPCM). The thermodynamic analysis indicates that almost all theoretical methods overestimate the enthalpy and Gibbs free energy. This also applies to Minnesota functionals, which are commonly recommended for thermochemistry studies. The best agreement with experimental results was obtained for the composite methods r²SCAN-3c and PBEh-3c, with the coefficient of determination (R² = 0.9972) indicating excellent correlation between r²SCAN-3c and experiment. Full article

Dielectric elastomer actuators (DEAs) are attracting much attention as candidates for next-generation flexible actuation. Among various DE matrices, polyacrylate rubber (AR) is especially promising owing to their intrinsically high dielectric constant (ε_r) and good mechanical performance. In particular, its mechanical behavior is close to that of porcine bladder tissue, making it a potentially good material for soft biomedical actuators for artificial bladder constructs. To achieve high actuated strain, which requires high ε_r, high breakdown strength, and low elastic modulus, an AR DE composite filled with silane-functionalized TiO₂ was fabricated, exhibiting good electromechanical performance enabled by strengthened interfacial polarization. To improve compatibility between TiO₂ and AR matrix, TiO₂ was preferentially modified with a silane coupling agent (CA) that features a double bond as its functional group, which can be introduced on TiO₂ surface and participate in vulcanization with AR, thereby forming co-crosslinking bridges that strengthen interfacial bonding, improve filler dispersion, and increase interfacial polarizability within the matrix. As a result, at relatively low filler loadings, the composite exhibits a significantly increased ε_r, while maintaining low modulus, low dielectric loss and high elasticity. The 10 CA@TiO₂/AR composite exhibits a maximal actuated strain of 7.9% at 31.9 kV/mm without pre-stretch, which is 1.48 times that of pure AR and 1.32 times that of the 10 TiO₂/AR composite. Full article

Understanding the adsorption of organic pollutants onto microplastics in aqueous environments is crucial for assessing their environmental behavior and ecological risks. Herein, we used density functional theory (DFT) computations to simulate the aqueous adsorption of 54 organic compounds onto three representative microplastics, namely polyethylene (PE), polyoxymethylene (POM), and polyvinyl alcohol (PVA). Afterwards, based on theoretical molecular structural descriptors, we developed six quantitative structure activity relationship (QSAR) models based on datasets of 43 and 54 organic compounds, respectively. The results demonstrated that the oxygen-containing POM and PVA microplastics exhibited weaker adsorption in the aqueous phase compared to that in the gas phase. Furthermore, it revealed that the electron-rich atoms, van der Waals volumes and molecular polarizability exert substantial effects on the adsorption process on microplastics in water. These robust QSAR models can enable the prediction of adsorption energies for various organic pollutants on microplastics, which can offer a rapid approach for generating adsorption data. Moreover, the insights into adsorption mechanisms can provide a theoretical basis for designing modified or alternative plastics with lower environmental risks. Full article

Niobium is a strategic critical mineral that supports emerging energy and high-end manufacturing. The geophysical parameters of carbonatite-alkaline rock-type niobium deposits constitute essential baseline data for regional geophysical exploration and prospecting target delineation. To clarify the geophysical response characteristics and exploration the significance of the Dagele niobium deposit in the Eastern Kunlun Region (western China). This study focuses on drill hole ZK3202. Samples from ore bodies, mineralized zones, and wall rocks of different lithologies were continuously measured. Combined with 1001.8 m of full-hole core digital logging data, statistical methods, including box plots, histograms, multi-parameter cross-plots, and correlation coefficient analysis, were applied to quantitatively investigate the physical property responses of lithologies such as calcite-biotite rock (ore body), calcite-bearing pyroxenite (mineralized zone) and amphibolite in the vertical profile. Lithological identification thresholds were established to divide the drill-hole into lithological and mineralized ore layers. The results show that the ore-bearing lithofacies exhibit a distinctive geophysical signature characterized by high density, strong magnetism, medium-low resistivity, high polarizability, and slightly elevated natural radioactivity, which clearly distinguishes them from surrounding from wall rocks. Based on five key parameters—density, magnetic susceptibility, resistivity, polarizability, and natural gamma—a lithological identification model for amphibolite and mineralized altered rock assemblages was established. This study also summarizes the multi-parameter coupling mechanism of ore-bearing lithofacies, which can effectively delineate favorable niobium-bearing horizons. This work fills a gap in the geophysical property characterization of carbonatite-alkaline complex-type niobium deposits in the Eastern Kunlun region and provides data support and regional reference for integrated gravity-magnetic-electrical-radioactive geophysical exploration, prospecting target delineation, and the exploration of similar niobium deposits in western China. Full article

We investigated the influence of transition metal coordination on the optical dispersion and thermo-optic behavior of the ionic liquid 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]). Refractive index measurements in the visible–near-infrared range (400–1000 nm), combined with temperature-dependent characterization (298–323 K), demonstrate that coordination with Al³⁺, Cd²⁺, Zn²⁺, and Mn²⁺ consistently increases the refractive index relative to the neat ionic liquid. All systems exhibit normal dispersion, following the hierarchy n(Al) > n(Cd) ≳ n(Zn) > n(Mn) > n([BMIM][SCN]), which reflects cooperative contributions from metal-centerd polarizability and coordination-induced modifications to density and electronic structure. Negative thermo-optic coefficients are measured for all samples, with [BMIM]₃[Al(SCN)₆] displaying the highest temperature sensitivity. Abbe diagrams and group-velocity dispersion analyses confirm a predictable index–dispersion trade-off and show that dispersion-related transport parameters are less temperature dependent than n(T). Collectively, these findings establish a structure–property framework for tuning refractive index, chromatic dispersion, and thermo-optic response via coordination chemistry, supporting the targeted design of thiocyanate-based ionic liquids for photonic components, thermal lenses, and dispersion-managed optical devices. Full article

The utilization and chemical transformation of carbon dioxide remains a pressing problem in modern chemistry. Numerous experimental and theoretical studies have focused on the interaction of CO₂ with amines. In this work, quantum chemical density functional theory (DFT) calculations of equilibrium geometries, energies, electronic and vibrational characteristics of CO₂-sensitive mono-, di-, tris-hydroxyamidines and their associates were carried out by the B3LYP/6-31G(d, p) method. The harmonic vibrational frequencies were scaled and compared with the experimental FTIR spectra for supporting wavenumber assignments. Natural bond orbital (NBO) analysis of the atomic charges and charge delocalization was employed to investigate the nature of hydrogen bonding in hydroxyamidine associates. We also used the intrinsically polarizable continuum model (IEFPCM), and the DFT-D3 method was applied to account for dispersion effects during associate formation. Using the 6-311+G(2d, p) basis set for tris-hydroxyamidine, and its adducts, a comparative analysis of the experimental and calculated ¹H NMR spectra was performed. Here, we considered non-trivial sites of carbon dioxide absorption and hydroxyamidine protonation, which, to our knowledge, have hardly been considered by other authors. Present DFT results agree rather well with the experimental data and support new insight into the formation of the PIL structure. Full article

This paper systematically studied the structural, mechanical, electronic, and optical characteristics of cubic KZnX₃ (X = F, Cl, Br, and I) perovskites through the density functional theory (DFT) in the Quantum Espresso framework. Structural optimization and stability analyses confirm that all compounds crystallize in the cubic Pm-3m phase and are thermodynamically, mechanically, and dynamically stable. Elastic constants indicate that the materials are anisotropic and ductile in nature. Calculations of Debye temperatures show a systematic decrease of 402 K (KZnF₃) to 158 K (KZnI₃), which is related to the increasing mass of halogen and its impact on the rigidity of the lattice. Electronic structure calculations show that all compounds are indirect bandgap semiconductors, with bandgaps systematically decreasing from 4.24 eV (KZnF₃) to 0.86 eV (KZnI₃) at the HSE06 level, enabling tunable semiconducting characteristics for optoelectronic applications. The analysis of the density of states and charge density indicates that the bonding between Zn and X is mixed ionic and covalent and that the bonding between K and X is mostly ionic. Calculations of optical properties show an increase in polarizability, absorption, refractive index and plasmonic response when heavier halogen is used, highlighting the potential of KZnX₃ perovskites for photovoltaic and optoelectronic devices. Overall, halogen substitution in KZnX₃ provides an effective strategy for tailoring electronic and optical properties. Full article

Organic solar cells require molecular materials with broad absorption and proper energy-level alignment to maximize photon harvesting and charge transport; in this context, this work focuses on the computational design and characterization of π-conjugated push–pull chromophores, providing an integrated evaluation of their electronic, thermodynamic, and optoelectronic properties for photovoltaic applications. The chromophores were optimized using DFT/ b3lyp/6-31g+(d,p) in Gaussian16, incorporating solvation effects through the CPCM model. Electronic, thermodynamic, and optical properties were investigated using DFT and TD-DFT/CAM-B3LYP/6-311+G(d,p), including the calculation of absorption and emission spectra, first hyperpolarizability, and two-photon absorption. The STQ-PP chromophores exhibit differentiated optoelectronic responses, with DTTQ-DPP-1 showing an energy gap of 0.82–0.86 eV, stabilized LUMO levels between −2.50 and −2.61 eV, high electronic polarizability, and optical absorption extended beyond 800 nm, favoring the harvesting of low-energy photons, whereas DTTQ-DPP displays a gap close to 2.70 eV and absorption predominantly localized in the UV region, associated with potentially inferior photovoltaic performance. Compared with commercial donor materials, DTTQ-DPP-1 exhibits a red-shifted absorption into the NIR and a smaller gap, indicating enhanced low-energy photon capture; its structural stability and increased rigidity further support its photovoltaic viability. Full article

The separation of xenon (Xe) and krypton (Kr) is very important for industrial applications and environmental protection. However, the lack of permanent dipoles, low polarizabilities arising from their spherical nature, and similar kinetic diameters make their efficient separation by porous adsorbents exceptionally challenging. This study explored the effects of pore geometry and surface polarity of a series of aluminum-based metal–organic frameworks (CAU-10-H, MIL-160, KMF-1, CAU-23) on Xe/Kr separation performance using a heteroatom engineering strategy. These MOFs are composed of AlO₆ clusters and bent dicarboxylic acid linkers, enabling us to systematically investigate the effects of pore size and heteroatom types on Xe/Kr separation performance. Among them, MIL-160 has a polar linker based on furan, showing the best balance performance. At 298 K and 1.0 bar, the uptake of Xe is 4.12 mmol g⁻¹ and the IAST selectivity is 7.63 for a Xe/Kr (20/80) mixture. The practical performance was verified by dynamic breakthrough experiments, which yielded a long Xe breakthrough time of 42.9 min g⁻¹. Grand Canonical Monte Carlo (GCMC) simulations and first-principles density functional theory (DFT) calculations revealed that the enhanced performance originates from cooperative confinement and polarization effects, with the furanyl oxygen atoms providing optimal Xe-binding sites. This work clarifies the structure–property relationships governing Xe/Kr separation in aluminum-based MOFs (Al-MOFs), highlighting the potential of heteroatom engineering for designing efficient noble gas adsorbents. Full article

Owing to their small size and surface hydrophobicity, microplastics (MPs) tend to act as vectors for various organic pollutants. However, in contrast to well-studied pollutants like polycyclic aromatic hydrocarbons, the sorption of benzene-series compounds on MPs has been seldom studied. To investigate the sorption process, the isotherms were determined for the sorption of three benzene-series sorbates by three polymers with different physicochemical properties. The linear sorption isotherms observed for PE indicate that sorbate uptake was dominated by partitioning into the bulk polymer. In contrast, the non-linear isotherms of PP and PVC imply that adsorption onto surfaces was the dominant mechanism. Sorption capacity of m-xylene and ethylbenzene increased in the following order: polyvinyl chloride (PVC) < polyethylene (PE) < polypropylene (PP). This order does not reflect the polarity or the crystallinity of the investigated MPs, suggesting the influence of additional factors (e.g., glass transition temperature, specific surface area) on the sorption of BTEX by MPs. In addition, the particle size and morphology of MPs are also factors affecting sorption capacity. The strong correlation between the sorption coefficients and sorbate hydrophobicity indicates that the hydrophobic interactions played a crucial role. Meanwhile, specific sorbate properties, such as electronic structure and molecular polarizability, are also significant factors that affect the sorption behaviors. Full article

Three novel metal complexes of the tridentate ligand 4-nitro-2-(quinolin-8-yliminomethyl)phenol (NQP) were synthesized and fully characterized using elemental analysis, TGA, magnetic susceptibility, FT-IR, NMR, and UV–Vis spectroscopy. Stoichiometric studies and characterization data proposed square-planar Pd(II), tetrahedral Zn(II), and octahedral Fe(III) geometries. Density functional theory calculations (B3LYP and B3LYP/6-311G(d,p) with LANL2DZ for metals) showed good agreement with experimental findings and revealed enhanced nonlinear optical properties, as evidenced by increased polarizability and hyperpolarizability values. Biological studies demonstrated significant antimicrobial activity, with the Pd–NQP complex exhibiting superior efficacy against bacterial and fungal strains compared to ofloxacin and fluconazole, following the order NQP < Zn < Fe < Pd. Cytotoxicity assays against Hep-G2, MCF-7, and HCT-116 cell lines revealed strong anticancer activity, particularly for the Pd(II) complex (IC₅₀ = 6.35–12.95 μ_g/μL), comparable to cisplatin. All complexes showed higher DPPH radical scavenging activity than ascorbic acid and strong DNA-binding affinity. Antimicrobial activity was further validated experimentally, while molecular docking studies elucidated favorable binding interactions with microbial proteins and cancer-related targets. Full article

The accurate modeling of carbohydrates is challenged by conformational flexibility, hydration, and many-body electrostatics. In this work, a polarizable bond dipole potential for carbohydrates (PBDPC25) is presented, in which C–O, O–H, and C–H bonds are represented as intrinsically polarizable dipoles. Electrostatic interactions are described through bond dipole coupling, with an orbital overlap contribution introduced to account for hydrogen bonding. For carbohydrate monomers, PBDPC25 reproduces conformational energies with a root-mean-square error (RMSE) of 2.13 kcal/mol. This accuracy exceeds that of GLYCAM06 (2.87 kcal/mol) and CHARMM36 (3.74 kcal/mol). It is also slightly better than the polarizable AMOEBA force field (2.82 kcal/mol). Optimized geometries are maintained within 0.15 Å of benchmark reference structures. This level of agreement is comparable to GLYCAM06 (0.21 Å) and close to CHARMM36 and AMOEBA (both 0.14 Å). Molecular dipole moments show excellent agreement with the reference data. Correlation coefficients exceed R² > 0.98. For carbohydrate–water clusters, hydration energies, including many-body contributions, are predicted with an RMSE of 3.50 kcal/mol. This represents a substantial improvement over GLYCAM06, CHARMM36, and AMOEBA. These results demonstrate that PBDPC25 provides a reliable framework for modeling carbohydrate conformations and local hydration effects. Full article