The underhand cut-and-fill mining method is widely employed in underground mines, especially when the quality of surrounding rock mass or ore body is inferior or subjected to high stresses. Such a method typically requires the construction of sill mats with cemented backfill to provide operators with safe artificial roofs. Accurate estimation of the minimum required strength of the sill mat is crucial to minimize binder consumption and ensure its stability upon base exposure. Over the years, only a few publications were devoted to determining the minimum required cohesion (c_min) of sill mats. None of them considered rock wall closure to be associated with the creep of surrounding rock mass. Moreover, the effect of rock wall closure associated with rock creep on the c_min of the sill mat remains unknown. Thus, a series of numerical simulations was performed to fill this gap. The influence of rock creep on the c_min of base-exposed sill mat was investigated for the first time. The numerical results indicate that Mitchell’s models could be suitable for sill mats subjected to negligible wall closure. However, this scenario is rare, especially when mine depth is large. In general, the c_min of sill mats increases as mine depth increases. Neglecting rock creep would significantly underestimate the c_min of sill mats. When mine depth is large and the rock mass exhibits severe creep, cemented backfill with ductile behavior (i.e., with low stiffness but enough strength) should be considered to reduce binder consumption and prevent crushing failure. In all cases, promptly filling the mined-out stope below the sill mat can improve its stability and reduce its c_min value.

Investigation techniques, such as uniaxial compression tests, acoustic emission, digital image correlation monitoring, and scanning electron microscopy, were used from macroscopic and microscopic perspectives to investigate the effects of gangue particle-size gradation on the damage characteristics of cemented backfill. The peak strength, acoustic emission characteristics, and failure modes of cemented backfills with different gangue size gradations were examined. Test results indicated that with an increase in the gradation coefficient, the compressive strength of the gangue-cemented backfill first increased and then decreased. When the gradation coefficient is 0.5, the maximum compressive strength of the backfill is 4.28 MPa. The acoustic emission counts during the loading of gangue-cemented fills with different gradation coefficients passed through three phases: rising, active, and significantly active. The number of internal pores and cracks, as well as the uneven distribution of their locations, cause differences in acoustic emission characteristics at the same stage and variations in the strength of the backfill due to the different gangue particle-size gradations in the filler sample.

Growing concerns about greenhouse gas emissions from underground mining have intensified the need for carbon reduction strategies at every stage. Shotcrete used in tunnel support presents a promising opportunity for carbon emission reduction. This study investigates the carbon absorption capacity, mechanical strength, and underlying mechanisms of shotcrete when exposed to varying CO₂ concentrations during the mine support process. Findings reveal that higher CO₂ concentrations during the initial stages of carbonation curing enhance early strength but may impede long-term strength development. Shotcrete samples exposed to 2vol% CO₂ for 14 d exhibited a carbonation degree approximately three times higher than those exposed to 0.03vol% CO₂. A carbonation layer formed in the shotcrete, sequestering CO₂ as solid carbonates. In practical terms, shotcrete in an underground return-air tunnel absorbed 1.1 kg·m² of CO₂ over 14 d, equivalent to treating 33 m³ of contaminated air. Thus, using shotcrete for CO₂ curing in return-air tunnels can significantly reduce carbon emissions, contributing to greener and more sustainable mining practices.

Large-scale underground projects need accurate in-situ stress information, and the acoustic emission (AE) Kaiser effect method currently offers lower costs and streamlined procedures. In this method, the accuracy and speed of Kaiser point identification are important. Thus, this study aims to integrate chaos theory and machine learning for accurately and quickly identifying Kaiser points. An intelligent model of the identification of AE partitioned areas was established by phase space reconstruction (PSR), genetic algorithm (GA), and support vector machine (SVM). Then, the plots of model classification results were made to identify Kaiser points. We refer to this method of identifying Kaiser points as the partitioning plot method based on PSR–GA–SVM (PPPGS). The PSR–GA–SVM model demonstrated outstanding performance, which achieved a 94.37% accuracy rate on the test set, with other evaluation metrics also indicating exceptional performance. The PPPGS identified Kaiser points similar to the tangent-intersection method with greater accuracy. Furthermore, in the feature importance score of the classification model, the fractal dimension extracted by PSR ranked second after accumulated AE count, which confirmed its importance and reliability as a classification feature. The PPPGS was applied to in-situ stress measurement at a phosphate mine in Guizhou Weng’an, China, to validate its practicability, where it demonstrated good performance.

As a refractory iron ore, the clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal. In this study, the microwave fluidization magnetization roasting of limonite was explored. The micromorphology, microstructure, and mineral phase transformation of the roasted products were analyzed using a scanning electron microscope, an automatic surface area and porosity analyzer, an X-ray diffractometer, and a vibrating sample magnetometer. Kinetic analysis was also conducted to identify the factors limiting the roasting reaction rate. Microwave fluidization roasting significantly increased the specific surface area of limonite, increased the opportunity of contact between CO and limonite, and accelerated the transformation from FeO(OH) to α-Fe₂O₃ and then to Fe₃O₄. In addition, the water in the limonite ore and the newly formed magnetite exhibited a strong microwave absorption capacity, which has a certain activation effect on the reduction roasting of limonite. The saturation magnetization and maximum specific magnetization coefficient increased to 23.08 A·m²·kg⁻¹ and 2.50 × 10⁻⁴ m³·kg⁻¹, respectively. The subsequent magnetic separation of the reconstructed limonite yielded an iron concentrate with an Fe grade of 59.26wt% and a recovery of 90.07wt%. Kinetic analysis revealed that the reaction mechanism function model was consistent with the diffusion model (G(α) = α²), with the mechanism function described as k = 0.08208exp[−20.3441/(R_gT)]. Therefore, microwave fluidization roasting shows significant potential in the beneficiation of limonite, offering a promising approach for the exploitation of refractory iron ores.

The effective reuse of iron phosphate residue (IPR) is the key issue in the recycling of spent LiFePO₄ batteries. Therefore, in this study, the reduction leaching of IPR in H₂SO₄ solution by adding iron powder as reducing agent was investigated and compared with direct leaching. The results show that the leaching rate of IPR reached 97% under the optimum reduction leaching conditions. Kinetic studies show that the activation energy for reduction leaching is 12.71 kJ/mol, while that of direct leaching is 21.57 kJ/mol. Moreover, the reduction leaching time is reduced by half and the acid consumption is reduced by 30% compared to direct leaching with the same leaching rate. This work provides a scientific guidance to the treatment of iron phosphate residue from the recycling of spent LiFePO₄ batteries.

Al₂O₃ and MgO serve as the primary gangue components in sintered ores, and they are critical for the formation of CaO–Fe₂O₃–xAl₂O₃ (wt%, C–F–xA) and CaO–Fe₂O₃–xMgO (wt%, C–F–xM) systems, respectively. In this study, a nonisothermal crystallization thermodynamics behavior of C–F–xA and C–F–xM systems was examined using differential scanning calorimetry, and a phase identification and microstructure analysis for C–F–xA and C–F–xM systems were carried out by X-ray diffraction and scanning electron microscopy. Results showed that in C–F–2A and C–F–2M systems, the increased cooling rates promoted the precipitation of CaFe₂O₄ (CF) but inhibited the formation of Ca₂Fe₂O₅ (C₂F). In addition, C–F–2A system exhibited a lower theoretical initial crystallization temperature (1566 K) compared to the C–F system (1578 K). This temperature further decreases to 1554 K and 1528 K in the C–F–4A and C–F–8A systems, respectively. However, in C–F–xM system, the increased MgO content raised the crystallization temperature. This is because that the enhanced precipitation of MF (a spinel phase mainly comprised Fe₃O₄ and MgFe₂O₄) and C₂F phases suppressed the CF precipitation reaction. In kinetic calculations, the Ozawa method revealed the apparent activation energies of the C–F–2A and C–F–2M systems. Malek’s method revealed that the crystallization process in C–F–2A system initially followed a logarithmic law (ln α or ln α²), later transitioning to a reaction order law ((1−α)⁻¹ or (1−α)^−1/2, n = 2/3) or the ln α² function of the exponential law. In C–F–2M system, it consistently followed the sequence f(α) = (1−α)² (α is the crystallization conversion rate; n is the Avrami constant; f(α) is the differential equations for the model function of C₂F and CF crystallization processes).

Hydrogen displays the potential to partially replace pulverized coal injection (PCI) in the blast furnace, and it can reduce CO₂ emissions. In this paper, a three-dimensional mathematical model of hydrogen and pulverized coal co-injection in blast furnace tuyere was established through numerical simulation, and the effect of hydrogen injection and oxygen enrichment interaction on pulverized coal combustion and raceway smelting was investigated. The simulation results indicate that when the coal injection rate decreased from 36 to 30 t/h and the hydrogen injection increased from 0 to 3600 m³/h, the CO₂ emissions decreased from 1860 to 1551 kg/t, which represents a 16.6% reduction, and the pulverized coal burnout decreased from 70.1% to 63.7%. The heat released from hydrogen combustion can not only promote the volatilization of pulverized coal but also affect the combustion reaction between volatilization and oxygen, which resulted in a decrease in the temperature at the end of the raceway. Co-injection of hydrogen with PCI increased the wall temperature near the upper half part of the raceway and at the outlet of the tuyere, which required a high cooling efficiency to extend the service life of the blast furnace. The increase in oxygen level compensated for the decreased average temperature in the raceway due to hydrogen injection. The increase in the oxygen content by 3% while maintaining constant hydrogen and PCI injection rates increased the burnout and average raceway temperature by 4.2% and 43 K, respectively. The mole fraction of CO and H₂ production increased by 0.04 and 0.02, respectively. Burnout can be improved through optimization of the particle size distribution of pulverized coal.

The iron and steel industries generate large amounts of unavoidable CO₂ emissions as well as considerable quantities of slags. More than one-half of the emitted CO₂ is produced in blast furnaces during ironmaking, and thus it is meaningful to use blast furnace slags to capture CO₂ while addressing the byproducts and flue gas of ironmaking. Mineral carbonation of slags is a promising route to achieve carbon neutrality and effective slag utilization. To exploit slag more effectively and capture CO₂ in flue gas, an in-depth investigation into the carbonation of blast furnace slags generated with different cooling methods was conducted. The effects of the solid–liquid ratio and introduced CO₂ concentration on carbonation were determined. The CO₂ uptake capacity of air-cooled slag (0.04 g/g) was greater than that of water-quenched slag. The CO₂ uptake capacities of the two slags were comparable with those of slags in previous works, indicating the potential of the two slags for CO₂ sequestration and utilization even with low-energy input and this fact suggests that this process is feasible.

The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy, and its distribution characteristics were determined. Numerical simulations confirmed that the freezing–overflow mechanism is the primary cause of hook formation. They also revealed that the freezing event occurs unpredictably, while the overflow event takes place during the positive strip time. The average pitch of oscillation marks (OMs) on the slab surface was 8.693 mm, while the theoretical pitch was 8.889 mm, with a difference of approximately 2%. This discrepancy primarily results from varying degrees of overflow, which affects the morphology of the OMs and the positions of their deepest points. Notably, this result further confirmed that the freezing and overflow in the meniscus were indeed caused by the periodic oscillation of the mold. Higher superheat hindered hook formation, leading to a negative correlation between the hook depth distribution around the slab and the temperature distribution within the mold. Therefore, the depth of the corner hook was greater than that of other positions, which was caused by the intensified cooling effect of the corner. Moreover, key factors influencing hook development were analyzed, providing insights into transient fluid flow and heat transfer characteristics within the mold. Transient fluid flow and heat transfer contributed to the randomness and tendency of hook formation. This randomness was reflected in the varying angles of the hooks, whereas the tendency was evident in the negative correlation between superheat and hook length. Based on the randomness and tendency of hook formation and its profile characteristics, a new method for controlling hook depth based on “sine law” is proposed.

The <001> orientation of the Goss texture aligned with the rolling direction is the most easily magnetized direction, effectively enhancing the magnetic properties of non-oriented silicon steel. In the present study, an ultra-thin high-silicon sheet of 0.2 mm with a strong Goss texture was successfully fabricated using a two-stage rolling method, achieving superior magnetic properties. The combination of suitable primary rolling reduction and intermediate annealing proved beneficial in promoting the formation of Goss texture. Electron back scatter diffraction (EBSD) was used to characterize micro-shear bands within deformed grains of secondary rolled sheets. Observations revealed that the recrystallized Goss nucleus originated from the Goss substructure of shear bands within deformed {111}<112> grains during the initial stages of recrystallization. The influence of stored energy and grain size on texture evolution was thoroughly investigated using quasi-in situ EBSD during recrystallization. In the initial stages, large deformed {111}<112> and near {111}<112> grains with high stored energy facilitated nucleation and growth of Goss and near-Goss grains within shear bands and reduced grain boundary nucleation. In the later stages, large deformed grains with low stored energy underwent a strain-induced grain boundary migration mechanism to nucleate. During the recrystallization, many recrystallized Goss and near-Goss grains clustered together, with Goss grains rotating towards near-Goss orientation. The resulting annealed ultra-thin 0.2 mm sheet with a pronounced Goss texture exhibited superior magnetic properties.

Through quenching and tempering (QT) and quenching and partitioning (Q&P) processes, this study aimed to investigate the effects of microstructural modifications on the corrosion behavior and corrosion-assisted mechanical degradation of medium Ni-bearing steel. The primary objective was the identification of strategies for the enhancement of the long-term lifespan and reliability of these alloys in neutral aqueous environments. Various electrochemical evaluations and microstructural characterizations were conducted to elucidate the relationship between heat treatment processes and corrosion behavior. The findings reveal that the conventional Q&P process formed partitioned austenite with a coarse size within the martensitic matrix, which led to an uneven distribution of Ni and high kernel average misorientation and resulted in an increased susceptibility to corrosion and corrosion-induced mechanical degradation. In addition, the corroded QT sample displayed preferential attacks around cementite clusters due to selective dissolution. By contrast, a slightly higher partitioning temperature, just above the martensite transformation start temperature, provided finely distributed austenite within bainite in the microstructure, which exhibited lower corrosion kinetics and reduced susceptibility to mechanical degradation in the corrosive environment. This study highlights the potential of microstructural optimization through the Q&P process with a high partitioning temperature as an effective technical strategy for achieving the superior durability and reliability of medium Ni-bearing steel alloys in neutral aqueous environments.

Amino acids have emerged as promising green alternatives to replace toxic inhibitors in corrosion protection applications. In this study, we present a one-step synthetic approach to get 4-(tert-butyl)benzoyl)methionine (P-Meth) and 4-(tert-butyl)benzoyl)cysteine (P-Cys) through the acylation reactions between methionine or cysteine and p-tert-butylbenzoic acid, respectively, which exhibit a super protective performance toward metals against corrosion. The corrosion rates of Q235 steel in 1 M HCl were reduced from 4.542 to 0.202 and 0.312 mg·h⁻¹·cm⁻² in the presence of 100 mg·L⁻¹ P-Meth and P-Cys, respectively. The surface structures of Q235 steel remained unbroken after 12 h in 1 M HCl medium. The charge transfer resistances of corrosion reactions were enhanced by 12 and 9 times in the presence of P-Meth and P-Cys, respectively. P-Meth and P-Cys were adsorbed onto the Q235 steel via chemical actions, which were accompanied by minimal physical action. Molecular dynamic simulations demonstrate the higher binding energy of P-Meth onto Q235 steel than P-Cys. The study contributes to the corrosion protection of metals with green and environmentally friendly methods.

Calcium–magnesium–alumina–silicate (CMAS) and/or molten salt corrosion have attracted increased attention, which is an important cause of thermal barrier coating (TBC) failure. In this study, the effect of CMAS and NaCl melting sequence on the corrosion mechanisms of yttria-stabilized zirconia (YSZ) TBCs was revealed through experiments and finite element simulations. The YSZ TBCs were prepared via atmospheric plasma spraying. Subsequently, the CMAS and NaCl corrosion experiments of the TBCs were conducted at 1250°C. Results indicated that the melting sequence of CMAS and NaCl could influence the TBC failure mode. The coating failure modes after CMAS + NaCl mixed corrosion and NaCl melting followed by CMAS melting were buckling failures. Conversely, the coating failure mode was observed to be spalling failures. This study provides data support for the optimization of TBC systems in complex corrosive environments.

Interstitial oxygen (O) contamination remains a substantial challenge for metal injection molding (MIM) of titanium alloys. Herein, this critical problem is successfully addressed by regulating the thermal debinding temperature and incorporating the oxygen scavenger LaB₆. Results indicate that the surface oxide layer (with a thickness of (13.4 ± 0.5) nm) of Ti6Al4V powder begins to dissolve into the Ti matrix within the temperature range of 663–775°C. O contamination in MIM Ti alloys can be effectively mitigated by lowering the thermal debinding temperature and adding LaB₆ powder. As a result of reduced dissolved O content, the slips of mixed <a> and <c + a> dislocations are effectively accelerated, leading to improved ductility. Moreover, grain refinement, along with the in situ formation of TiB whiskers and second-phase La₂O₃ particles, enhances the strength of the material. The fabricated MIM Ti6Al4V sample exhibits excellent mechanical properties, achieving an ultimate tensile strength of (967 ± 5) MPa, a yield strength of (866 ± 8) MPa, and an elongation of 21.4% ± 0.7%. These tensile properties represent some of the best results reported in the literature for MIM Ti6Al4V alloys. This study offers valuable insights into the development of high-performance MIM Ti alloys and other metal materials.

The current study investigates the hot deformation behavior of Al–12Ce–0.4Sc alloy with an isothermal hot compression test at 300–450°C/0.001–1 s⁻¹. Results show that the flow curves exhibit typical dynamic recovery (DRV) and slight flow-softening behavior. Additionally, the flow curves overlap owing to the dynamic strain aging (DSA) phenomenon at 400–450°C/0.01–0.1 s⁻¹. Two different constitutive models were developed using the experimental data for hot deformation: (i) strain-compensated Arrhenius model (Method I) and (ii) logistic regression model (Method II). The average stress exponent (n) and apparent activation energy (Q) are 14.25 and 209.58 kJ·mol⁻¹, respectively. The hot-working processing map shows that the optimal processing condition is 400°C/1 s⁻¹, and the maximum power dissipation efficiency is 22%. Stable and unstable domains indicated by the processing map were correlated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD) characterization techniques. The unstable domains are primarily associated with pro-eutectic Al₁₁Ce₃ intermetallic fracture and interfacial cracks between α-Al and pro-eutectic Al₁₁Ce₃.

Strong and ductile Al alloys and their suitable design strategy have long been desired in selective laser melting (SLM). This work reports a non-equilibrium partitioning model and a correspondingly designed Al–7.5Mg–0.5Sc–0.3Zr–0.6Si alloy. This model effectively quantifies the influence of Mg and Si on hot cracking in aluminum alloy by considering the non-equilibrium partitioning under high cooling rates in SLM. The designed Al–7.5Mg–0.5Sc–0.3Zr–0.6Si alloy exhibits no hot cracks and achieves a remarkably enhanced strength–ductility synergy (a yield strength of (412 ± 8) MPa and a uniform elongation of (15.6 ± 0.6)%), superior to previously reported Al–Mg–Sc–Zr and Al–Mn alloys. A tensile cracking model is proposed to explore the origin of the improved ductility. Both the non-equilibrium partitioning model and the novel Al–7.5Mg–0.5Sc–0.3Zr–0.6Si alloy offers a promising opportunity for producing highly reliable aluminum parts through SLM.

The evolution of the microstructure and mechanical properties of WE43 magnesium alloy during multipass hot rolling was investigated. Results revealed that multipass hot rolling promoted the formation of small second phases, which was conducive to multiple dynamic recrystallization, consequently improving the microstructure homogeneity and refining the average grain size from 34.3 µm in the initial material to 8.83 µm. Meanwhile, the rolling deformation rotated abundant c-axis of the grains in the normal direction, resulting in a strong fiber texture. The yield strength in the rolling direction (RD) was improved from 164 MPa in the initial material to 324 MPa in the Pass 3 sheet due to fine-grained strengthening, second-phase strengthening, and texture modification. In addition, the distribution maps of the deformation mechanism indicated that the yield strength anisotropy between the RD and the transverse direction (TD) can be attributed to the effects of the texture component on the dominant mechanism. The dominant deformation mechanism during the tensile test was the prismatic slip caused by the strong basal texture of the RD, whereas it had a lesser proportion of prismatic slip under the influence of the weak basal texture of the TD. Compared to the basal slip, the higher critical resolved shear stress of the prismatic slip resulted in a higher increase in yield strength along the RD at approximately 51 MPa than that along the TD (RD: increase of 160 MPa; TD: increase of 109 MPa).

This study successfully developed a series of carbon-sol-reinforced copper (Cu-CS) composite coatings by electrodeposition employing a superiorly dispersed carbon sol (CS) to avoid nanoparticle aggregation. The CS, characterized using transmission electron microscopy and zeta potential analysis, consisted of carbon particles with an approximate diameter of 300 nm uniformly distributed in the electrolytes. The characteristics of the composite coatings were examined via scanning electron microscopy to observe its microstructures, X-ray diffraction to detect its phase constituents, and durability testing to determine the wear and corrosion resistance. Results indicated a significant improvement in coating thickness, density, and uniformity achieved for the Cu-CS composite coating with the addition of 20 mL/L CS. Moreover, the Cu-CS composite coating exhibited a low wear volume (1.15 × 10⁻³ mm³), a high hardness (HV_0.5 137.1), and a low corrosion rate (0.191 mm/a). The significant contribution of carbon particles to the improvement of coating performance is mainly influenced by two factors, namely, the strengthening and lubricating effects resulting from the incorporated carbon particles. Nevertheless, overdosage of CS can compromise the microstructure of the Cu-CS composite coating, creating defects and undermining its functionality.

In-situ TiB₂/Al–Cu composite was processed by multidirectional forging (MDF) for six passes. The microstructure evolution of the forged workpiece was examined across various regions. The mechanical properties of the as-cast and MDFed composites were compared, and their strengthening mechanisms were analyzed. Results indicate that the grain refinement achieved through the MDF process is mainly due to the subdivision of the original grains through mechanical geometric fragmentation and the occurrence of dynamic recrystallization (DRX). DRX grains are formed through discontinuous DRX, continuous DRX, and recrystallization induced by particle-stimulated nucleation. A rise in accumulated equivalent strain (ΣΔε) results in finer α-Al grains and a more uniform distribution of TiB₂ particles, which enhance the Vickers hardness of the composite. In addition, the tensile properties of the MDFed composite significantly improve compared with those of the as-cast composites, with ultimate tensile strength and yield strength increasing by 51.2% and 54%, respectively. This enhancement is primarily due to grain refinement strengthening and dislocation strengthening achieved by the MDF process.

Aqueous zinc-ion batteries are regarded as promising electrochemical energy-storage systems for various applications because of their high safety, low costs, and high capacities. However, dendrite formation and side reactions during zinc plating or stripping greatly reduce the capacity and cycle life of a battery and subsequently limit its practical application. To address these issues, we modified the surface of a zinc anode with a functional bilayer composed of zincophilic Cu and flexible polymer layers. The zincophilic Cu interfacial layer was prepared through CuSO₄ solution pretreatment to serve as a nucleation site to facilitate uniform Zn deposition. Meanwhile, the polymer layer was coated onto the Cu interface layer to serve as a protective layer that would prevent side reactions between zinc and electrolytes. Benefiting from the synergistic effect of the zincophilic Cu and protective polymer layers, the symmetric battery exhibits an impressive cycle life, lasting over 2900 h at a current density of 1 mA·cm⁻² with a capacity of 1 mA·h·cm⁻². Moreover, a full battery paired with a vanadium oxide cathode achieves a remarkable capacity retention of 72% even after 500 cycles.

The advancement of wireless technologies has increased the global demand for ubiquitous connectivity. However, this surge has increased electromagnetic pollution. This study introduces a composite comprising a polymer matrix (polydimethylsiloxane, PDMS) and a magnetic filler (carbonyl iron powder, CIP) to effectively absorb electromagnetic waves (EMW) and suppress electromagnetic noise, while exhibiting good mechanical properties. Eutectic gallium–indium (EGaIn) liquid metal (LM) was introduced to improve the insulating properties of magnetic fillers. A core–shell structure was obtained by coating the CIP particles with EGaIn, thereby combining magnetic and dielectric materials to enhance EMW absorption. The fluid characteristics of the LM improved the mechanical properties, whereas its electrical conductivity enhanced interfacial polarization loss, thereby augmenting the dielectric loss value of the composites. Moreover, the application of mechanical strain enhanced the EMW absorption of the LM/CIP/PDMS composites due to the formation of a conductive LM network.

Doping small amounts at the A-site or B-site of SmCrO₃ ceramics is a promising approach for modifying their microstructure, as well as their magnetic and dielectric properties. In this study, polycrystalline ceramics of Sm_1−xNi_xCrO₃ (x = 0, 0.05, and 0.20) and SmCr_1−yNi_yO₃ (y = 0.05 and 0.20) were synthesized via a conventional solid-state reaction. X-ray diffraction validated that all the doped ceramics maintained an orthorhombic crystalline structure consistent with the Pbnm space group. Furthermore, X-ray photoelectron spectroscopy demonstrated the presence of Ni²⁺ ions in the doped specimens. Notably, doping resulted in significant enhancement of low-temperature magnetic properties, particularly in samples doped at the A-site, such as Sm_0.80Ni_0.20CrO₃. Compared with the pristine sample, the maximum magnetization of Sm_0.80Ni_0.20CrO₃ increased by approximately 60.9% and 93.5% in the zero-field cooling and field-cooling modes, respectively, in an external magnetic field of 100 Oe. Furthermore, the dielectric constants of the Ni-doped ceramics initially exceeded that of the pristine sample as the temperature increased. At equivalent doping ratios, A-site doping demonstrated superior performance over B-site doping, including higher magnetization, lower dielectric loss, and enhanced electrical quality factors.

Up to now, “Turn-on” fluorescence sensor exhibits promising potential toward the detection of heavy metal ions, anions, drugs, organic dyes, DNA, pesticides, and other amino acids due to their simple, quick detection, and high sensitivity and selectivity. Herein, a novel fluorescence method of detecting Cr³⁺ in an aqueous solution was described based on the fluorescence resonance energy transfer between rhodamine B (RhB) and gold nanoparticles (AuNPs). The fluorescence of RhB solution could be obviously quenched (“off” state) with the presence of citrate-stabilized AuNPs. However, upon addition of Cr³⁺ to AuNPs@RhB system, the fluorescence of AuNPs was recovered owing to the strong interaction between Cr³⁺ and the specific groups on the surface of citrate-stabilized AuNPs, which will lead to the aggregation of AuNPs (“on” state). At this point, the color of the reaction solution turned to black. Under optimal conditions, the limit of detection (LOD) for Cr³⁺ was 0.95 nM (signal-to-noise ratio, S/N = 3) with a linear range of 0.164 nM to 3.270 µM. Furthermore, the proposed method exhibits excellent performances, such as rapid analysis, high sensitivity, extraordinary selectivity, easy preparation, switch-on fluorescence response, and non-time consuming.

Traditional resistive semiconductor gas sensors suffer from high operating temperatures and poor selectivity. Thus, to address these issues, a highly selective nitrogen dioxide (NO₂) sensor based on lead sulfide (PbS) quantum dots (QDs)–lead molybdate (PbMoO₄)–molybdenum disulfide (MoS₂) ternary nanocomposites operating at room temperature was fabricated herein. The ternary nanocomposites were synthesized using an in situ method, yielding PbS QDs with an average size of ∼10 nm and PbMoO₄ nanoparticles in the 10- to 20-nm range, uniformly distributed on ultrathin MoS₂ nanosheets with an average thickness of ∼7 nm. The optimized sensor demonstrated a significant improvement in response to 1 ppm NO₂ at 25°C, achieving a response of 44.5%, which was approximately five times higher than that of the pure MoS₂-based sensor (8.5%). The sensor also achieved relatively short response/recovery times and full recovery properties. Notably, the optimal sensor displayed extraordinary selectivity toward NO₂, showing negligible responses to different interfering gases. Density functional theory (DFT) calculations were conducted to elucidate the underlying sensing mechanism, which was attributed to the enhanced specific surface area, the receptor function of both PbS QDs and PbMoO₄ nanoparticles, and the transducer function of MoS₂ nanosheets.