Search Results (7,588)

The Xiaoyinuogaigou (XYN) gold deposit is located in the central Erguna Metallogenic Belt, northeastern China, and represents a characteristic example of Mesozoic gold mineralization in the Mongol–Okhotsk orogenic province. Despite its economic significance, the timing of mineralization and the nature of the ore-forming fluid system have not been well constrained. To address these questions, a systematic investigation of fluid inclusions, isotopes, geochemistry, and geochronology was conducted. The study reveals that: (i) four types of fluid inclusions are identified in auriferous quartz veins, with co-existing aqueous liquid-vapor and NaCl daughter-mineral three-phase inclusions, indicating the involvement of at least two chemically distinct fluids; (ii) the ore-forming fluids are characterized by moderate temperatures (163.2–357.6 °C), low to moderate salinities (3.06–11.34 wt% NaCleqv.), and H–O isotope compositions (δD = −133.3 to −112.3‰; δ¹⁸O fluid (SMOW) = +1.74 to +4.06‰) consistent with a hydrothermal system incorporating a substantial non-magmatic water component; and (iii) REE geochemistry and sulfur isotopes (δ³⁴S = +4.47 to +11.75‰, mean +8.29‰, n = 4) indicate that ore-forming materials were derived at least in part from the ore-hosting granite porphyry. Zircon U–Pb geochronology constrains the granite porphyry crystallization to 180 ± 3 Ma, and hydrothermal monazite U–Pb dating yields an age of 162.3 ± 3.6 Ma (MSWD = 0.95), for a Middle Jurassic hydrothermal event. We therefore conclude that XYN is an epizonal orogenic gold deposit formed during the late compressional to post-collisional transition of the Mongol–Okhotsk orogeny. Full article

Serial femtosecond crystallography (SFX) using X-ray free-electron lasers (XFELs) enables the determination of macromolecular and chemical structures along with minimizing radiation damage. Sample delivery using the fixed-target (FT) scanning method minimizes both sample consumption and physical damage during delivery. When XFELs penetrate the FT sample holder, background scattering generated from the holder material can interfere with data processing, which consequently indicates the importance of selecting an appropriate FT sample holder material according to specific experimental conditions. We introduce a polyethylene terephthalate (PET) film-based sample holder that can be applied to data collection for both small-molecule and macromolecule XFEL diffraction studies. Background scattering analysis revealed that the PET film-based sample holder produced relatively low X-ray scattering in the high-resolution range (<10 Å) compared with a nylon mesh-based sample holder composed of polyimide and nylon mesh. Conversely, background scattering generated from the PET film was relatively higher in the low-resolution range (>10 Å) than that with the polyimide film; however, this low-resolution background was negligible for data processing. Thin PET films were manually perforated to promote the deposition of microcrystals in random orientations. The crystal samples were then deposited onto the films and sealed with an additional PET film to prevent dehydration. Using the PET film-based sample holder, we successfully collected diffraction data from barium titanate without unwanted background scattering from the sample holder. Furthermore, the room-temperature structure of glucose isomerase was determined using the PET film-based sample holder. Therefore, PET film-based sample holders can be applied to both small-molecule and macromolecular SFX data collection. Full article

Metallurgical slags produced in the zinc–lead, copper, iron and steel metallurgical industries are characterized by a variety of technical parameters and varying chemical and mineral compositions, which depend on the type of raw material and the technological process selected and its workflow. These slags are characterized by a high content of valuable elements, including Cu, Pb, Zn, and Fe, which form complex multiphase conglomerates. In the chemical composition of Zn-Pb smelting slags, the contents of the dominant elements, i.e., Fe, Zn, and Pb, range from a few to several dozen %. These elements occur mainly in the form of polyphase oxides and silicates. The chemical composition of Cu smelting slag contains up to a few % Cu and up to several dozen % Fe, with these elements mainly forming silicates and sulphides. Iron and steel metallurgy slag contains up to several dozen % Fe, which occurs mainly in the form of silicates, oxides, and spinels. Due to their phase composition, metallurgical slags stored in landfills can have a negative impact on the environment. The phase composition of slags is one of the main factors determining their behavior in a weathering environment, i.e., their ability to release metals when exposed to atmospheric factors such as precipitation or temperature. On the other hand, such high concentrations of elements in metallurgical slags mean that they become anthropogenic deposits, and the phase composition of the slags determines how the deposited slags are processed. The aim of this article is to present the mineralogical and chemical characteristics of Zn, Pb, Cu and steel metallurgical slags deposited in landfills, along with an assessment of these materials as a source of secondary raw materials. Full article

The benefits of additive manufacturing (AM, i.e., 3D printing) have made it one of the most widely used and favored production techniques across a variety of industries. In the current study, the influence of geometry and thermal aging on the mechanical strength of AMed parts has been investigated. In this context, specimens based on fused deposition modeling were printed using polylactic acid material. The specimens with three distinct geometries were created and analyzed since the geometry of AMed parts affects their mechanical performance. In this study, tensile tests were conducted under static loading circumstances, specifically on dumbbell-shaped, smooth, and V-notched test coupons. Furthermore, we conducted accelerated thermal aging between $-5 °$C and 35 °C, which is below the glass temperature of the material under investigation, to assess the impact of the thermal environment. In addition, a series of finite element models were developed to study the stress distribution and deformation in the examined components. According to the results, for unaged specimens, smooth samples demonstrated the highest fracture load at 1980.5 N, while dumbbell-shaped samples recorded the lowest at 1173.9 N. Moreover, the V-notched specimens sustained higher fracture loads compared to dumbbell-shaped samples across both aged and unaged conditions. This study’s findings demonstrate that in designing 3D-printed parts, consideration must be given to their geometric appearance and environmental operating circumstances. Full article

Metal parts produced by directed energy deposition go through a complex thermal history during the deposition stage, which can result in heterogeneous microstructures and the accumulation of residual stress. While individual post-processing heat treatments are widely used to address these issues, the industrial logistics of manufacturing large components often demand specific sequences of combined treatments (e.g., applying stress relief prior to substrate detachment to prevent distortion, followed by high-temperature solubilization, or vice versa). The microstructural and mechanical consequences of altering this sequence remain underexplored. Therefore, this study aimed to investigate the effects of different post-processing heat treatment sequences on the mechanical properties of AISI 316L deposited through laser-directed energy deposition. Tensile and Charpy impact tests were carried out on the specimens under five conditions: (i) as-built; (ii) stress relief; (iii) solubilization; (iv) stress relief and solubilization; and (v) solubilization and stress relief. A statistical analysis of variance supported a comparison between each treatment’s influence on the mechanical properties under each condition. Furthermore, the typical microstructures were assessed by optical microscopy, scanning electron microscopy (SEM) equipped with electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). The solubilization treatment reduced the ultimate tensile strength (from ~618 MPa to ~576 MPa) and the yield stress (from ~424 MPa to ~299 MPa), while no significant change was observed in elongation (ranging from 27% to 38%) due to high data dispersion. The stress relief, however, did not significantly change these mechanical properties. Considering the heat treatment combinations, the solubilization had a stronger impact on tensile stress than the stress relief, regardless of the treatment order. Impact resistance was not significantly affected by any of the heat treatments, maintaining an average of ~114 J. The solubilization treatment fully recrystallized the microstructure, while the stress relief did not promote any significant changes at an optical microscopy level. Ultimately, this study demonstrates that the microstructural transformations induced by the solubilization step dominate the final mechanical baseline, indicating that the sequence order is not a determining factor. This finding grants critical flexibility for industrial manufacturing logistics, allowing stress relief to be strategically applied when most convenient for dimensional stability without compromising final part performance. Full article

A novel low-temperature method to synthesize a hybrid carbon material (HCM) is reported. The synthesis relies on a chemical vapor deposition (CVD) approach, using zeolite NaY as a scaffold structure and acetone as the carbon source. The deposition temperature was 500 °C at a pressure of 46 ± 1 kPa. Following the growth of the HCM, the material was treated with HF to remove the scaffold, and the resultant materials were characterized by high-resolution scanning electron microscopy (HR-SEM), energy-dispersive X-ray spectroscopy (EDS) mapping, transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman microscopy, and Brunauer–Emmett–Teller (BET) surface area analysis, showing heterogeneous morphology. The results demonstrate that synthesis at low temperatures produces a robust hybrid material that can adopt different configurations and/or morphologies by modifying the scaffold structure. Full article

This study presents a comprehensive investigation of the structural, morphological, and optical properties of aluminum phthalocyanine (AlPc) and silicon phthalocyanine (SiPc) thin films prepared by the close space sublimation (CSS) method, deposited at different evaporator temperatures of 350 °C, 400 °C, and 450 °C, including heterostructures incorporating an indium tin oxide (ITO) layer. Scanning electron microscopy revealed a clear temperature-dependent evolution of surface morphology, with both materials transitioning from isolated crystallites to dense, highly crystalline films. SiPc exhibited higher nucleation density and earlier film densification, while AlPc showed more pronounced grain growth at elevated temperatures, accompanied by crack formation due to internal stress. Optical absorption spectra indicated a red shift in absorption maxima with increasing deposition temperature, associated with improved crystallinity and reduced defect density. The presence of ITO significantly modified the optical response, introducing additional absorption features in the near-infrared region due to interference effects and free-carrier contributions. Fluorescence measurements revealed enhanced emission intensity with increasing temperature for AlPc, while SiPc showed weaker emission overall. The incorporation of ITO led to substantial fluorescence enhancement and the appearance of additional near-infrared emission bands, highlighting the importance of interface engineering. Transmittance spectra demonstrated that ITO-based heterostructures provide a balance between transparency and absorption, with selective attenuation in the 600–800 nm range, enabling band-stop filter behavior. Raman analysis revealed opposite temperature-dependent trends: increasing structural order in AlPc and gradual disorder in SiPc. X-ray diffraction confirmed the crystalline nature of both materials, showing temperature-induced improvements in crystallinity and crystallite size, as well as distinct differences in molecular packing and preferred orientation. These results demonstrate the potential of AlPc and SiPc thin films as functional optical materials with tunable structural and optical properties. Full article

Among the vast array of technologies available for surface modification of materials, sputtering emerges as one of the most versatile methods through coating deposition. Included in the family of physical vapor deposition (PVD) techniques, sputtering allows the production of coatings with a great variety of characteristics, based on a bottom-up approach that forms coatings from individual species (atoms or ions). This versatility is achieved by controlling: (i) the layer architecture, from monolithic to multilayers, (ii) the structures, from amorphous to nanocrystalline or nanocomposite, until highly crystallized, including epitaxial; (iii) the morphologies, from very porous through columnar or zig-zag to very dense and featureless; (iv) the chemical composition, allowing the deposition of metallic, polymeric, ceramic or composite materials types. In this paper, after a brief introduction of sputtering as a deposition technology, we will review the application of sputtering for depositing protective coatings to which an extra functionality is provided: (a) aesthetic color; (b) high-temperature lubrication; and (c) temperature sensing ability. Full article

Rapid corrosion and poor coating adhesion continue to limit the use of magnesium alloys as temporary orthopedic implants. The two-stage laser process was developed to separate the high-temperature melting of 45S5 bioactive glass (BG) from the low-melting-point AZ31 substrate. Femtosecond-laser grids with spacings of 100, 200, and 300 μm were first produced on AZ31 to provide anchoring sites. Then, the target 45S5 BG was suspended above the substrate, locally melted with CO₂ laser, and transported onto the textured surface by gas jet. The 200 μm grid texture for Mg substrate with lowest water contact angle could give the highest tape-test adhesion rating (4B). At the selected deposition conditions of 20 W and 20 L·min⁻¹, two coating cycles produced a continuous layer approximately 50.5 μm thick. Relative to bare Mg alloy, this double-layer coating increased polarization resistance from 1.20 × 103 to 1.39 × 10⁵ Ω·cm² and decreased corrosion current density from 8.70 × 10⁻⁴ to 5.33 × 10⁻⁶ A·cm⁻². It also limited alkalization and mass loss during 28 days in simulated body fluid. As such, the double-layer surface coating supported apatite formation and improved MC3T3-E1 proliferation and alkaline phosphatase activity. These findings indicated that suspended-target deposition was able to form adherent, bioactive glass coatings on magnesium while limiting direct thermal damage to the substrate. Full article

Amidst the intensification of strategic mineral exploration, the discovery of concealed and deep-seated deposits within covered areas and the peripheries of existing mines has become a critical challenge and a central focus of contemporary research. “Dongchuan-type” (DCT) copper deposits represent a key mineralization style within the SW Yangtze Block. However, significant exploration breakthroughs have stagnated over the past three decades. Consequently, advanced exploration prediction research is urgently required to guide deep-resource evaluation. Using the Shizishan copper deposit in the Yimen area as a representative case, this study applies the theory of “metallogenic geological body prediction” to construct a tripartite model encompassing “metallogenic geological bodies, metallogenic structures and structural planes, and metallogenic characteristic markers”. The Shizishan deposit is classified as a sedimentary-reformed type, characterized by multi-episodic mineralization involving initial sedimentary processes, non-magmatic hydrothermal activity, and subsequent structural-magmatic hydrothermal overprinting. Key metallogenic geological bodies include ore-bearing stratigraphic associations, basin-margin faults, NE-trending fold–fault systems, and deep-seated concealed intrusions. Metallogenic structural planes comprise primary ore-controlling surfaces, secondary fold-related structures, and potential deep-seated magmatic intrusive interfaces. Alteration patterns display a distinct vertical zonation: shallower levels show medium-to-low temperature hydrothermal processes (silicification, carbonatization, sericitization, and chloritization), whereas deeper portions reveal high-temperature magmatic–hydrothermal indicators, specifically skarnization and intense silicification. This study proposes that the integration of “stratigraphy + structures + concealed intrusions” should serve as the primary criterion for target screening in deep exploration. By integrating geophysical and geochemical datasets into this model, three promising exploration targets were delineated within the Yimen area. These findings provide a refined theoretical framework for large-scale prospecting of DCT. Full article

Background: This study evaluates transdermal delivery of tamoxifen (TXN) as an alternative to the oral route of administration in treating breast cancer, which is the leading cause of cancer-related death in women globally. Oral TXN, a Class II drug, is associated with first-pass metabolism and serious side effects, including secondary cancers. Objectives: To enhance transdermal delivery, lipid-based transethosomes (TRS) were formulated using three different 2⁴ factorial designs with various non-ionic surfactants, including Tween 20^®, Span 20^®, and Span 80^®. Methods: Optimized TRS formulations were incorporated into HPMC-based gels and characterized for morphology, drug content, pH, viscosity, spreadability, ex vivo skin penetration, and deposition. Additionally, cytotoxicity and stability were assessed. Results: All TXN-TRS gels were suitable for transdermal use; however, Span 20^®-based TRS gel demonstrated the highest skin penetration (40.3 ± 1.5 µg/cm²), representing a 127-fold enhancement rate compared with the non-ethosomal TXN gel. In line with the enhanced penetration profile, cellular studies on MCF-7 cells showed concentration-dependent cytotoxicity, reaching 91.24 ± 1.01% inhibition at 2% w/w after 72 h, with an IC₅₀ value of 0.85 ± 0.02% w/w. Stability testing showed all formulations were more stable under refrigeration than at dry room temperature storage, supporting their potential as preclinical transdermal tamoxifen delivery platforms. Conclusions: Span 20^®-based TXN transethosomal gel markedly enhanced skin penetration while maintaining potent cytotoxic activity, supporting its further preclinical evaluation as a promising transdermal alternative to oral tamoxifen. Full article

Silver complexes are potential antimicrobial agents that trigger destructive processes in bacterial cells, leading to their death. Their ability to simultaneously stimulate tissue regenerative properties also makes them promising components in the development of medical materials. A common complication arising from the treatment of bone tissue damage is hospital-acquired infection, requiring repeated revision surgeries. The use of bone grafts with antibacterial properties can help solve this problem. New pyridine complexes of silver(I) with thiophenecarboxylic (Htph) and nitric acid anions have been synthesized: [Ag(tph)(py)₂]_n·nHtph (1, py—pyridine) and [Ag(bpy)]_n·nNO₃ (2, bpy—4,4′-bipyridine), the structures of which have been determined using X-ray analysis. Despite the fact that 2 is a known structure, we were able to obtain new cell parameters by conducting an X-ray diffraction analysis at a lower temperature of 100 K. According to X-ray diffraction data, both compounds are polymers in which the cationic part is formed by linear fragments (CN_Ag = 2) [Ag(py)₂]⁺ (1)/[Ag(bpy)₂]⁺ (2), and acid anions act as counterions. The presence of intermolecular and non-valent π-π interactions provides additional stabilization of supramolecular levels. Aqueous solutions 1 and 2 are stable for two weeks, according to UV-Vis data. Incubation of crosslinked resorbable polymer matrices functionalized separately with complex 1 or 2 in saline solution revealed a sustained, prolonged release of silver ions over 14 days. Evaluation of the antimicrobial potential of 1 and 2 against Gram-positive/Gram-negative species and fungi demonstrated moderate, controlled bacteriostatic growth inhibition broadly across tested strains, confirming the bifunctionality of the crosslinked hybrid matrix systems—moderate suppression of bacterial growth while simultaneously stimulating tissue regeneration. An increase in cell viability, expressed in their active proliferation under the influence of complexes 1 and 2 up to 156%, as well as calcium deposition, indicates the high cytocompatibility and pro-mineralization capacity of the new compounds. Full article

In the present work, thin TiO₂ films were obtained by the sol–gel spin-coating method on glass and ITO-covered glass substrates. The crystallization evolution of the thin films was studied by the X-ray Diffraction (XRD) technique. The results indicate that the films’ crystalline structure was greatly affected by substrate type. X-ray photoelectron spectroscopy (XPS) revealed the chemical states of the TiO₂ films and proved the formation of TiO₂ on ITO substrates. Field Emission Scanning Electron Microscopy (FESEM) showed that the TiO₂ films deposited on the ITO glass possessed a uniform and homogeneous surface morphology. The influence of optical properties (transmittance, reflectance, and optical band gap) on substrate type, the number of layers and annealing temperatures was determined. Spectroscopic data confirmed high transparency of the TiO₂ films obtained on ITO substrates as the transmittance in the visible spectral range was close to 85%. The obtained results reveal that thin TiO₂ films on ITO substrates can be an excellent candidate for photovoltaic and optoelectronic applications. Full article

Dry reforming of methane (DRM) represents a promising route for the valorization of CO₂ captured from industrial emissions through high-temperature catalytic conversion. In this work, a LaMn_1−xNi_xO₃ perovskite catalyst (x = 0.25, 6 wt% Ni) was synthesized as a powder by solution combustion synthesis and subsequently deposited onto γ-alumina supports to obtain a structured catalyst. X-ray diffraction confirmed the formation of the perovskite structure, characterized by corner-sharing BO₆ octahedra with Ni substitution at the B-site. H₂-temperature-programmed reduction (H₂-TPR) revealed the reduction of Mn⁴⁺ and Mn³⁺ species to MnO, accompanied by the complete reduction of oxidized Ni species to metallic Ni over the investigated temperature range. Raman spectroscopy of the spent catalyst indicated negligible carbon deposition after DRM. Moreover, the Mn–O stretching band shifted from 657 cm⁻¹ in the fresh catalyst to 643 cm⁻¹ after reaction, consistent with changes in the manganese oxidation state associated with the collapse of the perovskite structure and the formation of MnO. During a 25 h stability test at 700 °C, the powdered LaMn_1−xNi_xO₃ catalyst achieved a CH₄ conversion of 75% at a WHSV of 60 L g⁻¹ h⁻¹. DRM tests performed with the structured catalyst confirmed the catalytic performance under larger-scale operating conditions and different reaction parameters, including temperature, residence time, and CH₄/CO₂ feed ratio, reaching CH₄ conversions of up to 94% at 800 °C. Full article

After in situ leaching of weathered crust elution-deposited rare earth ore (WREO), large amounts of residual ammonium (RA) salts remain in the ore body and slowly release, causing persistent ammonia-nitrogen pollution in surrounding waters. This study proposes using magnesium chloride for in situ elution remediation of closed mines. Column experiments were conducted to evaluate the effects of eluent concentration, liquid–solid ratio, flow rate, pH, and temperature on residual ammonium removal, and a kinetic model was established based on the shrinking unreacted-core model. The results show that increasing Mg²⁺ concentration, temperature, or flow rate accelerates the eluting rate, with temperature being the most influential. A higher liquid–solid ratio in the tested range could enhance the elution efficiency of residual ammonium, but it will substantially raise the production cost. Weakly acidic pH 4–6 favors the reaction, while alkaline conditions inhibit it. Kinetic analysis indicates inner particle diffusion control, with an activation energy of 6.03 kJ/mol and a reaction order of 0.3009. Under optimal conditions of 0.1 mol/L Mg²⁺, 2:1 liquid–solid ratio, 0.6 mL/min, pH 4–6 and room temperature, elution efficiency reaches 95.45%. This work provides theoretical and technical support for green remediation of historical ammonium contamination in WREO. Full article