Search Results (106)

The stele pavilion at the Jiezhou Guandi Temple in Shanxi Province is a significant Qing-dynasty architectural structure within one of China’s most renowned temple complexes dedicated to Guan Yu. However, its polychrome paintings have suffered severe deterioration due to prolonged weathering, and the composition, technological characteristics, and historical alterations of these paintings remain poorly understood. In this study, six polychrome pigment samples and one red oil-coating sample collected from different structural parts of the pavilion were systematically analyzed using laser Raman spectroscopy, scanning electron microscopy with energy-dispersive spectroscopy, X-ray diffraction, and pyrolysis-gas chromatography/mass spectrometry. The results show that the pigment layers primarily consist of mineral pigments including iron red, cinnabar, red lead, iron yellow, lavendulan, carbon black, and ultramarine, together with the organic pigment indigo. The oil coatings and polychrome paintings were restored in different periods. The initial oil coating, applied directly to the wood surface, has completely fallen off, whereas the later reapplication employed a single-layer ash ground with calcite aggregate and a binder of heat-bodied tung oil and rosin, indicating a simplified formula. The paint ground layer, dominated by kaolinite, contains pig blood, drying oil, and rosin, reflecting continuity with the Shanxi blood-based ground preparation tradition. These findings provide essential material evidence for conservation and offer a valuable case study for the technological history of Qing-dynasty regional architectural paintings in Shanxi. Full article

As global photovoltaic (PV) installation capacity grows rapidly, the environmental pollution and resource waste from the large-scale end-of-life (EOL) wave have drawn increasing attention. Traditional disposal methods such as landfilling and incineration are no longer viable, making green recycling a logical path for the PV industry. This paper reviews recent progress in the disassembly and recycling of EOL crystalline silicon (c-Si) PV modules. It first describes the structural material composition of c-Si PV modules and summarizes global recycling policies and regulatory frameworks. It then analyzes the mechanisms and process parameters of major delamination technologies, including mechanical crushing, pyrolysis, thermal cutting, high-voltage pulse fragmentation, solvent-based approaches, and laser peeling. Methods for purifying silicon and recovering precious metals such as silver and copper are also covered. Finally, key challenges in the recycling field and future development trends are discussed, with the aim of supporting the advancement of c-Si PV recycling technologies and the sustainable development of related industrial chains. Full article

Relatively low-cost titanium carbide (TiC) materials and metal matrix composites (MMC) are proposed for waste-to-hydrogen conversion. Two types of steels are used as bases prepared from EN 10088 flat products, namely X2CrTi12 (1.4512, AISI 409) and X5CrNi18-10 (1.4301, AISI 304). TiC is mixed with TRIBALOY^® T-800 alloy in powder form and applied via laser-directed energy deposition (DED-LB) over the substrates. For the powder mixture, Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) are performed. The raw materials are investigated for the processes that occur in them under heating. After the solidification of the molten mixture, grinding and polishing are performed to achieve a thin layer. The studies of the obtained MMC include interface zone assessment, hardness and Young’s modulus distribution, microstructural analysis, and visual defect evaluation. Advanced sensors for acoustic emission (AE) and Electrical Contact Resistance (ECR) provided characterization together with micro-scratch testing. The use of photoluminescence spectroscopy is proposed for the new composite materials. The electron transfer pathway can be studied with time-resolved spectroscopy. Renewable energy production by breaking down waste into hydrogen-rich syngas can be achieved through pyrolysis, followed by steam reforming and purification. The obtained novel materials show promising application solutions with increased durability, corrosion, and wear resistance. Full article

Detection of nanoplastics in drinking-water systems is only the first analytical step toward exposure interpretation; the next challenge is source attribution. This review examines molecular fingerprinting and transformation pathways that can link nanoscale polymer signals to source waters, drinking-water treatment, distribution infrastructure, packaging materials, laboratory background, or aging processes across the potable-water chain. Nanoplastics are treated here as operationally defined particles below 1 µm, including intentionally manufactured primary nanoplastics and secondary nanoplastics generated by fragmentation, abrasion, weathering, treatment, storage, or packaging stress. The synthesis evaluates how polymer identity, particle morphology, surface oxidation, additive and oligomer profiles, thermal degradation markers, matrix context, and quality assurance/quality control (QA/QC) can be combined into defensible source assignments. Analytical platforms considered include surface-enhanced Raman spectroscopy (SERS), atomic force microscopy–infrared spectroscopy (AFM-IR), optical photothermal infrared spectroscopy (O-PTIR), stimulated Raman scattering microscopy (SRS), pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS), asymmetric flow field-flow fractionation coupled to Py-GC/MS (AF4-Py-GC/MS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and chemometric workflows. The central conclusion is that source attribution cannot be inferred from polymer identity alone; robust interpretation requires convergent evidence from particle-level chemistry, polymer-specific mass, additive or marker-ion signatures, aging state, blanks, recovery, and contextual sampling design. Full article

Microplastic monitoring needs methods that operate directly in water with minimal sample handling. Conventional techniques such as infrared and Raman spectroscopy and pyrolysis–GC/MS provide polymer-specific information but require sample preparation and delayed laboratory analysis. We propose an optical sensor concept for real-time, in situ microplastic assessment, based on multispectral pulsed transmission in the visible range using synchronized laser-diode lines and the directly transmitted signal through an active sensor volume. After calibration on particle-free water, each particle event reduces to a water-normalized transmission whose deficit is set by geometrical beam–particle overlap and the wavelength-dependent extinction efficiency. The weak polymer absorption is represented by the Urbach-tail formalism, the refractive-index-related redirection of light by a Fresnel-based, surface- and orientation-averaged probability of direct transmission, and particle size and shape are decoupled through an effective optical length. The coupled nonlinear system is solved for the bounds of the polymer absorption coefficient per candidate geometry. Because each polymer occupies a bounded region in multi-wavelength absorption space fixed by its band gap and structural state, the method can, in principle, separate structural modifications of identical composition, such as low- and high-density polyethylene. This is a sensor concept with a model-based proof of concept, not full environmental validation. Experimental verification on real reference particles is reported separately; the present article establishes the measurement model and inversion scheme that this verification builds on. Full article

Increasing environmental pollution has intensified the focus on sustainability, encouraging the development of eco-friendly materials. This study reports the synthesis of binary (ZnO–TiO₂) and ternary (SnO₂–ZnO–TiO₂) compounds and their loading with Au/Ag/Pt/P noble metals (NMs) to enhance photodegradation efficiency under visible light compared to pristine TiO₂. The compounds were synthesized in a single step via laser pyrolysis, and then noble metal deposition through chemical impregnation and reduction was performed. Structural and morphological analyses revealed TiO₂-based nanoparticles with varied morphologies decorated with noble metal nanoparticles with sizes between 2 and 6 nm (for Pt and Pd). Photocatalytic tests demonstrated a significant improvement in Methyl Orange (MO) degradation under visible light, especially for Ag-loaded samples. The degradation rate increased from 1.03 × 10⁻³ min⁻¹ (TZ) to 22.65 × 10⁻³ min⁻¹ (TZS_Ag), while it was 0.09 × 10⁻³ min⁻¹ for the commercial P25 sample. Biocompatibility assays indicated lower cytotoxicity than Degussa P25, with Au- and Pd-loaded samples showing improved compatibility with HaCaT and HEK293 cells. Overall, these findings demonstrate that the developed TiO₂-based nanocomposites, designed through a novel and sustainable strategy combining binary/ternary heterostructures with noble metal loading, are promising candidates for efficient visible light-driven photocatalytic environmental decontamination with enhanced biological compatibility. Full article

Fly ash (FA) from Zhundong coal combustion features high alkali/calcium content and a low Si/Al ratio, limiting its potential for conventional utilization. To enable its high-value application, six size-fractionated samples (FA1–FA6) were characterized via laser particle sizing, SEM-EDS, XRF, XRD, FT-IR, and TGA, to elucidate particle-size-dependent physicochemical and thermal properties. The results show that the size distribution centered at 48–150 μm (~71%). With decreasing size, the morphology shifted from irregular aggregates to smooth vitreous spheres. The chemical composition exhibits significant elemental segregation; the SiO₂ content decreases with decreasing particle size, while active components such as CaO, MgO, and Fe₂O₃ are significantly enriched in fine particles. The thermal conversion behavior is regulated by particle size: The combustion reaction under an air atmosphere conforms to the second-order kinetic model, with the activation energy decreasing from 192.73 kJ·mol⁻¹ for coarse particles (>150 μm) to 63.53 kJ·mol⁻¹ for fine particles (<43 μm); under a nitrogen atmosphere, the weight loss originates from the removal of structural water and the decomposition of carbonates, and fine particles exhibit a higher pyrolysis activation energy (504.15 kJ·mol⁻¹) in the high-temperature stage (850–940 °C) due to being rich in high-crystallinity carbonates. The results of this study elucidate the structure–activity relationship of “particle size-composition-activity” for Zhundong coal fly ash and propose a graded utilization scheme where coarse fractions are suitable for low-grade building fillers, while fine fractions can be used as feedstocks for coal pyrolysis catalysts and functional adsorbents, providing a theoretical basis for its targeted resource utilization based on particle size fractionation. Full article

We report the synthesis of Fe/N/C ORR electrocatalysts by an original collinear CO₂ laser pyrolysis of liquid aerosol droplets in various configurations and compared them to a catalyst synthesized in the classical perpendicular one. While the precursors were always injected at the bottom side of the reactor, two collinear configurations of the laser entry into the reactor are considered: by the Top Side (T.S.) or by the Bottom Side (B.S.). The two corresponding catalysts sets show significant different ORR performances. An in-depth XPS analysis and fitting of the N1s spectra allowed for drawing the ORR performance as a function of FeN_x sites components. An original approach considering the energy delivered to a quantity of precursors in J.g⁻¹, linked to the flame temperature feature, evidenced very different conditions for perpendicular CO₂ laser pyrolysis and each of the two collinear configurations. This mass-weighted energy delivered in the classical perpendicular configuration is too low to allow for the formation of FeN_x sites and the resulting ORR performance is extremely poor, suggesting a marginal role of nitrogen species without interaction with iron atoms. In contrast, the delivered mass-weighted energies are sufficient in both collinear configurations to produce FeN_x sites. The ORR performance for catalysts produced in these both configurations is positively correlated with the amount of energy deposited on the precursors. The ORR performance in the T.S. laser configuration is positively correlated to the amount of FeN_x sites. The best performing catalysts obtained in the B.S. configuration show an opposite variation. These trends, and the ORR performance degradation of B.S. catalysts under prolonged chronoamperometry are discussed in light of the effect of temperature on the formation of the various kind of FeN_x sites. A tentative explanation is given, considering that N1s XPS fitting with a single FeN_x component may hinder the fact that Pyridinic sites components may contain a part of FeN_x sites, as suggested by theoretical calculation from the literature. The best catalysts obtained in this work by collinear configuration show similar performances to those obtained by double stage perpendicular pyrolysis previously reported with an ORR onset potential of ~860 mV. Full article

Titanium carbonitride (TiCN) has emerged as a significant material, bridging the gap between traditional binary carbides and nitrides to offer a comprehensive combination of superior mechanical strength, exceptional wear resistance, and excellent chemical stability. This review comprehensively surveys the research progress in TiCN materials, tracing their evolution from coating technologies to the forefront of nanoparticle synthesis and application. We begin by examining conventional physical vapor deposition (PVD) and chemical vapor deposition (CVD) techniques for producing TiCN coatings, highlighting their roles in extending the service life of cutting tools, forming tools, and components subjected to abrasive and corrosive environments. The discussion then shifts to the synthesis of TiCN nanoparticles, covering advanced methods such as laser ablation, solvothermal processes, and precursor pyrolysis, with a critical analysis of their advantages and limitations in controlling particle size, morphology, and stoichiometry. The enhancement in the nanoscale formulation of TiCN on mechanical properties including hardness, fracture toughness, and load-bearing capacity is through grain refinement and nanocomposite strengthening mechanisms. Furthermore, the review delves into the corrosion protection mechanisms imparted by TiCN, whether as a dense coating/film or as a reinforcing nanophase in composite matrices. Finally, we identify current challenges in scalable synthesis and phase stability, and propose future directions, such as the development of multi-functional TiCN-based nanocomposites and hybrid coating architectures for next-generation applications in extreme environments. This work aims to provide a structured reference that connects fundamental material properties with applied technological advancements across the micro- to nanoscale. Full article

An ultrafast laser system combined with an optical delay line allowed ablation and in-scription at 1 kHz and 1 GHz pulse burst within transparent polyimide films. The two-photon-induced absorption results in clean surface ablation, while inscription results in polymer decomposition, creating carbonised regions within the polymer. Three pulse bursts at 1 GHz increased the observed coupling to the material significantly. Modified regions (with linewidths down to a few microns) were investigated using optical microscopy, white light interferometry, SEM and Raman spectroscopy, supporting the increasing carbon density relative to the pristine polymer. As depth of field was only a few microns at high NA, 3D micro-structuring was achieved. Polymer decomposition produces gaseous products, resulting in internal stress and thus affecting inscription fidelity. An inscribed subsurface electrode with dimensions of 5 mm × 0.3 mm × 3 μm connected to conducting vias had a resistance of R = 10.6 ± 0.2 kΩ, along with resistivity of ρ ~ 0.19 Ω cm; hence, it had DC conductivity, σ ~ 5.3 Scm⁻¹. This conductivity is similar to that of bulk graphite and could well form the basis of future flexible sensors, demonstrating single-step 3D subsurface inscription of carbon or laser-induced graphene structures. Full article

The carved lacquer horse-hoof-shaped box excavated from Yulin, Shaanxi Province, represents a typical example of lacquerware preservation in the arid environment of northern China, exhibiting multiple deterioration phenomena, including substrate deformation, lacquer film peeling, and pigment fading. To systematically analyze its structural composition and craftsmanship features, this study employed multiple analytical techniques, including ultra-depth microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), confocal laser micro-Raman spectroscopy (Raman), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Based on these analyses, a targeted conservation protocol was developed. Results revealed that the carved lacquer horse-hoof-shaped box has a wooden substrate structure, with the lacquer ash layer composed of mixed materials, including calcium carbonate (CaCO₃), quartz (SiO₂), and hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂). The lacquer film layer contains Chinese lacquer and plant oils, with cinnabar applied as surface decoration. Based on these findings, a stratified reinforcement conservation strategy was proposed: under dynamic monitoring with optical fiber sensors and three-dimensional scanning, the wooden substrate was reinforced with moisture-curable polyurethane (MCPU), the lacquer ash layer was strengthened with acrylic emulsion (Primal AC33), aged areas were restored with nano calcium hydroxide (Ca(OH)₂) aqueous dispersion, and polyethylene glycol (PEG 400) poultice application was implemented to restore the flexibility of the lacquer film. This research significantly enhanced the integrity and stability of the carved lacquer horse-hoof-shaped box, providing practical evidence and technical references for the scientific conservation of lacquerware excavated from arid regions of northern China. Full article

The present study investigates the synthesis and dispersibility process of iron oxide nanoparticles using laser pyrolysis with isopropanol vapors as a sensitizer agent. Similar to previous experiments (iron oxide nanoparticles synthesized by laser pyrolysis using ethylene as sensitizer gas), iron pentacarbonyl (Fe(CO)₅) was employed as an iron precursor; however, instead of the classic ethylene, isopropanol was chosen as a sensitizer, which indicated beneficial features (especially enhanced dispersibility in water) in the as-synthesized nanoparticles. Structural and elemental analysis confirmed the size range of the nanoparticles (nanometric), with crystallite sizes under 10 nm. Both raw nanoparticles, as well as the oleic acid stabilized ones, exhibited excellent colloidal stability in both water and organic fluids (Toluene, Chloroform, and DMSO): around 100 nm hydrodynamic diameter and more than 40 mV for zeta potential. The study highlights the advantages of using isopropanol as a sensitizer in the production of high-purity iron oxide nanoparticles from laser pyrolysis, particles that showcase superior dispersibility and functionalization potential. Full article

Analysis of pyrobitumen in reservoirs can yield key information about hydrocarbon evolution, which may provide vital insights for deep- to ultra-deep hydrocarbon exploration in high- to over-mature petroliferous deep basins. The Ediacaran Dengying Formation in the Penglai area of the Sichuan Basin contains large-scale gas reservoirs, where pyrobitumen is extensively present. To understand the hydrocarbon accumulation and alteration processes in these reservoirs, in this study, we systematically investigated the characteristics of the reservoir pyrobitumen using detailed petrographic analysis and laser Raman spectroscopy. The results indicated that four types of reservoir pyrobitumen are present: pyrobitumen with isotropic (type I), mosaic (type II), fibrous (type III), and honeycomb (type IV) textures. Pyrobitumen in the dolomite reservoirs of the Deng 2 and Deng 4 members of the Dengying Formation often co-occurs with hydrothermal minerals, including saddle dolomite, quartz, and fluorite. The equivalent vitrinite reflectance (Rmc Ro%) calculated indicated that the pyrobitumen is over-mature, with Rmc Ro% values ranging from 3.46% to 3.89%. In addition, significant differences were observed in the Raman parameters between the four types of pyrobitumen: type IV shows the greatest degree of structural ordering, while type II exhibits the highest level of disordering, with types I and III exhibiting intermediate structural ordering. Finally, the spatial distribution of the four types of pyrobitumen indicated that hydrothermal pulses driven by the Emeishan Large Igneous Province toward the end of the Permian Period may be primarily responsible for the extensive cracking of paleo-oil pools, causing the development of types II–IV pyrobitumen and gas generation. Full article

Aluminum powder is the most commonly used metal fuel in the industry of explosives and propellants. The research progress in preparation technology, reactivity and application of nano-aluminum in explosives and propellants is systematically reviewed in this paper. The preparation technology of nano-aluminum powder includes mechanical pulverization technology (such as the ball milling method and ultrasonic ablation method, etc.), evaporation condensation technology (such as the laser induction composite heating method, high-frequency induction method, arc method, pulsed laser ablation method, resistance heating condensation method, gas-phase pyrolysis method, wire explosion pulverization method, etc.), chemical reduction technology (such as the solid-phase reduction method, solution reduction method, etc.) and the ionic liquid electrodeposition method, each of which has its own advantages. Some new preparation methods have emerged, providing important reference value for the large-scale production of high-purity, high-quality nano-aluminum powder. The reactivity differences between nano-aluminum powder and micro-aluminum powder are compared in the thesis. It is clear that the reactivity of nano-aluminum powder is much higher than that of micro-aluminum powder in terms of ignition performance, combustion performance and reaction completeness, and it has a stronger influence on the detonation performance of mixed explosives and the combustion performance of propellants. Nano-aluminum powder is highly prone to oxidation, which seriously affects its application efficiency. In addition, when aluminum powder oxidizes or burns, a surface oxide layer will be formed, which hinders the continued reaction of internal aluminum powder. In addition, nano-aluminum powder may deteriorate the preparation process of explosives or propellants. To improve these shortcomings, appropriate coating or modification treatment is required. The application of nano-aluminum powder in mixed explosives can improve many properties of mixed explosives, such as detonation velocity, detonation heat, peak value of shock wave overpressure, etc. Applying nano-aluminum powder to propellants can significantly increase the burning rate and improve the properties of combustion products. It is pointed out that the high reactivity of nano-aluminum powder makes the preparation and storage of high-purity nano-aluminum powder extremely difficult. It is recommended to increase research on the preparation and storage technology of high-purity nano-aluminum powder. Full article

Nanocrystals of Eu-doped GaN powders are produced via pyrolysis of a viscous compound made from europium and gallium nitrates. Furthermore, carbohydrazide is used as a fuel and toluene as a solvent; subsequently, a crucial nitridation process is carried out at 1000 °C for one hour. A slight shift of 0.04 degrees toward larger angles was observed for the X-ray diffraction patterns in the Eu-doped GaN powders regarding the undoped GaN powders, while Raman scattering also displayed a slight shift of 10.03 cm⁻¹ toward lower frequencies regarding the undoped GaN powders for the vibration mode, E₂(H), in both cases indicating the incorporation of europium atoms into the GaN crystal lattice. A scanning electron microscope micrograph demonstrated a surface morphology for the Eu-doped GaN with a shape similar to elongated platelets with a size of 3.77 µm in length. Energy-dispersive spectroscopy and X-ray photoelectron spectroscopy studies demonstrated the europium elemental contribution in the GaN. The X-ray photoelectron spectroscopy spectrum for gallium demonstrated the binding energies for Ga 2P_3/2, Ga 2P_1/2, and Eu 3d_5/2, which could indicate the incorporation of europium into the GaN and the bonding between gallium and europium atoms. The transmission electron microscope micrograph showed the presence of nanocrystals with an average size of 9.03 nm in length. The photoluminescence spectrum showed the main Eu³⁺ transition at 2.02 eV (611.69 nm) for europium emission energy, corresponding to the ⁵D₀ ⟶ ⁷F₂ transition of the f shell, which is known as a laser transition. Full article