Search Results (7,671)

6063 aluminum alloy has broad application prospects in aerospace and microelectronic thermal management systems due to its good thermal conductivity and moderate strength. However, its extremely high hot cracking susceptibility during the laser powder bed fusion (LPBF) process limits the direct manufacturing of complex components. This study proposes a strategy combining material composition modification with advanced structural design. By introducing TiH₂ nanoparticles (1.0~4.5 wt.%) to modify the 6063 aluminum alloy powder, Diamond-type porous structures based on triply periodic minimal surfaces (TPMS) were successfully fabricated using LPBF technology. The results show that the introduction of TiH₂ significantly suppresses the solidification cracking of the aluminum alloy. The underlying mechanism is that the L1₂-structured Al₃Ti particles, generated by the in situ decomposition of TiH₂ in the melt pool, provide high-density heterogeneous nucleation sites. This leads to a drastic decrease in the average grain size from 30.46 μm to 0.75 μm (a reduction of 97.5%), achieving a remarkable columnar-to-equiaxed transition (CET). In terms of mechanical properties, the 3.0 wt.% TiH₂ addition group exhibits excellent plateau stress (28.5 MPa) and energy absorption capacity, which is mainly attributed to the synergistic effect of fine-grain strengthening and Orowan dispersion strengthening. Thermal tests reveal that the thermal conductivity of the 3.0 wt.% group reaches 123 W/(m·K) at 100 °C. The healing of cracks reconstructs the macroscopic heat conduction paths, resulting in a significant improvement in thermal conductivity compared with the unmodified group. This work provides a theoretical reference for the development of high-performance, crack-free, and multi-functional integrated aluminum alloy components via additive manufacturing. Full article

Metal–polymer hybrid composites blend the high strength and stiffness of metals with the low weight and corrosion resistance of polymers. This synergy is expected to provide better crashworthiness, energy absorption, and design flexibility compared to traditional single-material structures. The present research intended to examine the crashworthiness features of an aluminium/CFRP structure under various operating conditions by optimizing process parameters through Design Expert software and experimental investigation. The design of the experiment was carried out using Design Expert software version 13 with response surface methodology (RSM) where working temperature, isothermal holding time, and crushing speed are taken as process variables. The test results demonstrate that the peak load, energy absorption (EA), and specific energy absorption (SEA) are significantly higher for the sample with working temperature, isothermal holding time, and crushing speed set at 25 °C, 13 h, and 5 mm/min, respectively. Moreover, EA and SEA are also relatively higher for this sample compared to the other samples. The test results showcased that temperature is a decisive factor for the mechanical properties of the tube, which is clearly reflected in experimental results. The higher peak force and EA indicate greater strength and a more energy-dissipative system. Moreover, a close correlation was observed between the experimentally measured and RSM-based optimization. Hence, RSM was found to be suitable for designing the experiments and for understanding the failure modes of the CFRP/aluminium structure. Full article

Laser lift-off (LLO) is a critical process for separating ultra-thin polyimide (PI) films in flexible electronics manufacturing, yet traditional methods often induce thermal and mechanical damage due to high laser energy processing. To address this, we propose a low-threshold LLO method by integrating carbon nanotubes (CNTs) at the interface between a 500 nm PI film and a glass substrate. The interfacial thermal dynamics and separation quality were evaluated through finite element simulations and experimental validations using a 355 nm ultraviolet nanosecond laser. Results demonstrate that CNTs significantly enhance interfacial ultraviolet absorption and promote lateral heat diffusion due to their high axial thermal conductivity. This mechanism broadens the thermal decomposition zone and suppresses vertical heat transfer, thereby reducing the required LLO threshold from 180 mJ/cm² to 120 mJ/cm². Furthermore, the integration of CNTs reduces interfacial adhesion and alters the separation dynamics, resulting in the formation of smoother blisters with increased diameters and reduced heights compared to conventional LLO. These effects effectively minimize thermal and mechanical damage to the ultra-thin PI film and its integrated devices. This CNT-assisted LLO approach provides an efficient, low-damage solution for ultra-thin film separation, showing strong potential for advancing high-performance flexible electronics. Full article

While carbon fiber-reinforced polymer (CFRP) composites are widely utilized in aerospace applications due to their exceptional specific strength and stiffness, they are inevitably subjected to impact loads during service, which can easily induce internal damage such as delamination. To mitigate these issues, this study investigates the low-velocity impact behavior of an SMA-reinforced CFRP U-shaped structure, emphasizing the critical role of curing-induced residual stresses. A numerical model incorporating the thermal-mechanical manufacturing history was developed and validated against experimental data. Results indicate that while embedded superelastic SMA wires effectively suppress crack propagation and enhance energy absorption, neglecting residual stresses leads to a significant overestimation of structural rigidity and peak loads. Due to the coefficient of thermal expansion mismatch between the SMA wires and the resin matrix, the SMA-CFRP system exhibits higher sensitivity to initial internal stresses than pure CFRP. By accounting for the residual stress field, the relative error in predicted peak force and absorbed energy for the SMA-CFRP model was reduced from 9.3% to 3.5% and 18.9% to 7.8%, respectively. These findings demonstrate that residual stress lowers the failure threshold and is essential for capturing the synergistic effects of SMA phase transformation and matrix damage, providing a more accurate reconstruction of the structural energy balance. Full article

Against the backdrop of global energy landscape restructuring, the advancement of the “dual-carbon” goals, and escalating external uncertainties, coal, as the “ballast stone” of China’s new energy system, faces new challenges in terms of supply chain stability and security. Therefore, scientifically assessing China’s coal supply chain resilience (CSCR) is of significant theoretical and practical importance for systematically identifying its supply vulnerabilities and ensuring energy supply security under extreme conditions. In the paper, we construct a composite evaluation indicator system using national statistical data from 2010 to 2024. We operationalize resilience across the following four capacities: resistance, absorption, recovery, and adaptive capacity. Annual resilience levels are measured using an integrated framework. This framework combines an improved entropy weight method, TOPSIS, and gray relational analysis (GRA). We then use the indicator contribution degree and obstacle degree models to identify the most influential factors. The results indicate that China’s CSCR followed a fluctuating upward, W-shaped trajectory during 2010–2024, with a marked acceleration after 2020. Resistance and absorption capacities display pronounced volatility. Recovery and adaptation capacities improve steadily. The dominant obstacle factors include the share of intelligent coal production capacity, labor productivity per employee, the scale of workforce security, and the working-capital turnover ratio. These findings provide empirical evidence and policy-relevant insights for strengthening China’s CSCR and reinforcing national energy security. Full article

Clay-based composite materials offer a low-carbon pathway for improving the environmental performance of the construction sector while maintaining relevance for architectural and heritage applications. A structured qualitative literature review was conducted, supported by thematic classification and exploratory bibliometric mapping (VOSviewer), based on peer-reviewed studies published between 2015 and 2025 relevant to the topic of clay minerals, stabilization, fibers, polymers, alkali activation, properties, performance, and applicability in architecture. According to the results obtained from the synthesized literature, it is seen that clay-based composites achieve performance improvement through complementary mechanisms: fiber reinforcement improves ductility, crack behavior, and energy absorption, polymer modification helps improve cohesion and water resistance and alkali activation transforms calcined aluminosilicate precursors into high-strength binding systems. The synthesis identifies three dominant performance mechanisms governing clay-based composites. Selected alkali-activated clay composite materials are reported to exhibit compression strengths higher than 60 MPa, and certain optimized systems may be able to provide lower thermal conductivity and lower levels of carbon emission in comparison with ordinary cement-based materials. The contribution of this paper lies in the synthesis of these material modification techniques and resulting performance aspects for their applicability in architecture, clarifying the potential of clay-based composites for sustainable construction, heritage compatible interventions, and future material development. By integrating material science with architectural applications, this study identifies the potential of clay-based composites for sustainable and heritage-compatible approaches to contribute to sustainable and circular construction practices, while also outlining key challenges and future research directions focused on optimization, large-scale implementation, and heritage-compatible innovation. Full article

The need to create lightweight materials with better mechanical properties has led to the use of Fiber Reinforced Composites (FRCs)s in the aerospace and automotive industries. The mechanical behavior of FRCs is heterogeneous, especially in conditions of low-velocity impact (LVI). The impact events cause structural damage, where most of the available literature deals with mono- or bi-composites in controlled situations. This work will present the results of studying the behavior of mono, bi- and tri-hybrids with carbon, glass and Kevlar fiber-reinforced epoxy. The sequences of the laminate stacks, number of plies and laminate thickness in the drop weight testing were across velocities of 1.91 to 3.91 m/s at drop heights of 19 to 79 cm. The dominant pillars of LVI, such as peak load, energy absorption and the modes of damage, were analyzed. The glass-dominated laminates peaked at 5.67 kN, while the Kevlar-dominated laminates reached peak flow in ductile collapse with greater quantities of absorbed energy. The leaders in strength and energy were the hybrids of Kevlar–glass (KG) cross-ply at 8.08 kN and 47.28 J and quasi-isotropic Kevlar–carbon–glass (KCG) at 9.12 kN and 47.25 J, showcasing a balance of strength and toughness. The rest, holding a greater quantity of Kevlar, ranging in thickness and cross-plies, were shaped with a load center. The experimental conclusion is that hybridization improved impact resistance and ductility, which is best supported by the glass/carbon rigidity-layered laminates. Such understanding directs the design work of future composite materials for better impact control. Full article

In most amorphous materials, the concentration of Urbach tail states is larger than the concentration of dangling bond states. However, absorption accounting for the Urbach tail while disregarding the dangling bonds is commonly used or derived by spectroscopic characterizations of amorphous films from a single spectrum, mostly due to the insufficient accuracy of such characterizations. This paper proposes an advanced envelope method (AEM) for transmittance spectrum T(λ), aiming to resolve this problem. The novelties in AEM are: improved preprocessing of T(λ), extending the envelopes deeper into the region of strong absorption (RSA), enhanced determination of the refractive index n(λ) in the region of weak absorption, optimization of both n(λ) and the extinction coefficient k(λ) in RSA, as well as analysis of the types of electron transitions and calculation of their energy gaps. Three single magnetron sputtered a-Si films deposited on glass substrates are characterized by AEM, and three other relevant methods that disregard deep-levels. The best accuracy is achieved when these films are characterized by AEM. It is demonstrated that the absorption coefficient α(λ) of each of these films distinguishes electron transitions via dangling bond states from those via tails states, and the DOS corresponds to the Mott–Davis model of amorphous materials. Full article

The formation and size evolution of gas-phase nanoparticles (NPs) in laser ablation inductively coupled plasma mass spectrometry critically influence aerosol transport, plasma ionization efficiency, and ultimately analytical accuracy. Nevertheless, burst-mode laser ablation, as an efficient and versatile strategy for controlling gas-phase NP size, remains insufficiently explored. Here, we combine experimental investigations and theoretical analysis to elucidate the mechanisms of gas-phase nanoparticle formation and size control by tuning the interpulse interval in burst-mode femtosecond (fs) laser ablation. The mean nanoparticle size exhibits a non-monotonic dependence on interpulse spacing, decreasing with a narrowing size distribution as the interval increases from 0 to 300 ps, and then increasing with distribution broadening at longer delays up to 1000 ps, closely correlating with ablation-crater depth. A characteristic transition at ~300 ps is identified, where both nanoparticle size and crater depth reach a minimum, revealing a critical timescale in pulse–plume–surface interactions. Simulations show that the interpulse interval governs the redistribution of laser energy between the surface and plume, driving a transition from surface-dominated ablation to plume-dominated absorption and partial recovery of surface coupling. This delay-dependent framework provides a unified explanation for nanoparticle formation, where particle size is determined by the competition between plume-mediated fragmentation and surface-driven material supply, and offers a basis for tailoring NP size distributions via temporal pulse shaping. Full article

Although amine-based post-combustion carbon capture is among the most established routes for CO₂ capture, it suffers from the high energy demand associated with amine regeneration. Recent research proposals suggest that microwave or frequency-tuned infrared heating may lead to more efficient amine regeneration processes. However, such approaches inherently introduce oscillating electromagnetic fields whose non-thermal effects on reaction pathways and energetics remain poorly understood. In this series paper, we employ high-accuracy quantum computational chemistry calculations to quantify the non-thermal effects of external electric fields on CO₂ absorption and desorption in monoethanolamine (MEA) and triethanolamine (TEA) under both aqueous and non-aqueous conditions. In this first part, we focus on static electric fields in order to establish a mechanistic reference framework helpful for interpreting non-thermal effects arising from frequency-tuned infrared laser excitation, which are addressed in Part II of this series. Our results show that static electric fields stabilize CO₂–amine reaction products, lowering absorption barriers, while consistently increasing both activation energies and reaction enthalpies associated with the amine regeneration process. This effect is particularly pronounced for MEA, where carbamate species become progressively more resistant to conversion to zwitterion as the field strength increases. These findings demonstrate that non-thermal static electric field effects counter the fundamental requirement for low-energy amine regeneration. By defining this intrinsic mechanistic limitation, the present study provides a useful baseline for assessing infrared laser-assisted carbon capture and underscores the importance of carefully selecting excitation frequencies to avoid adverse non-thermal stabilization effects. Full article

Crude glycerin (CG) is an energy-dense ingredient capable of partially or fully replacing corn in high-concentrate diets for ruminants. Its rapid ruminal absorption, favorable fermentative profile, and absence of lactic acid production may support safer adaptation to intensive feeding systems. The aim of this study was to evaluate the effects of replacing corn with CG (300 g/kg DM) on growth performance, feeding behavior, rumen morphometry, and proteomic responses of ruminal papillae in feedlot lambs. Sixty-five Santa Inês × Dorper lambs were assigned to either a control diet or a diet containing CG and were evaluated during pre-adaptation, adaptation, and finishing phases. Replacing corn with CG slightly reduced average daily gain (p = 0.02), without affecting final body weight, dry matter intake, or carcass yield (p > 0.05). Lambs fed CG exhibited lower subcutaneous fat thickness (p = 0.04) and reduced neutral detergent fiber intake during feeding behavior assessments (p < 0.05). Rumen papillae showed higher mitotic index and greater epithelial activity throughout the feedlot period, regardless of treatment. Proteomic analysis revealed upregulation of proteins involved in epithelial integrity (Claudin-1, Occludin) and mitochondrial energy metabolism (ATP synthase β, glycerol kinase) in CG-fed lambs, alongside downregulation of proteins related to oxidative stress and inflammation (HSP70, Annexin A1, SOD1, Peroxiredoxin-6). These findings demonstrate that CG promotes beneficial molecular adaptations in the ruminal epithelium without compromising carcass traits, supporting its use as a safe, functional, and sustainable alternative to corn in lamb finishing systems. Full article

Conventional uniform-thickness expansion-tube energy-absorbing structures suffer from excessively high initial peak crushing forces (IPCFs) and sub-optimal energy absorption efficiency. Inspired by the gradient stiffness characteristics of the inter node-to-node structure in Buddha’s Belly Bamboo, this study proposed an expansion-tube energy-absorbing structure design featuring a gradient stiffness. An LS-DYNA finite element simulation model was first established, validated through experimental results, and subsequently subjected to multi-objective optimization. The analysis results demonstrate that the stiffness-gradient expansion-type energy-absorbing structure designed in this study not only effectively reduces the IPCF during energy absorption but also further enhances its buffering and specific energy absorption (SEA). Full article

Multispectral LiDAR can simultaneously obtain distance and spectral information and shows great potential for underwater detection. However, absorption and scattering caused by suspended particles in water lead to energy attenuation and multiple scattering, which affect echo intensity and ranging accuracy, while the propagation characteristics under multi-wavelength conditions remain insufficiently studied. In this study, a simplified underwater propagation simulation model for multispectral LiDAR is established based on the equivalent spherical-particle assumption, combining Mie scattering theory with a semi-analytical Monte Carlo method. The effects of particle size on echo intensity and ranging error are analyzed under fixed concentration conditions. Based on this model, a detection-threshold-constrained optimal wavelength selection criterion is formulated. Multi-distance analysis (3, 5, 8, and 15 m) confirms that the preferred wavelength is primarily governed by particle size and remains stable across depths. The results show that the optimal detection wavelength shifts with particle size, being about 560 nm for fine particles and gradually moving toward the 400–480 nm blue–green band for larger particles. Experimental validation shows that the simulation-based ranging correction reduces RMSE by 9.4–25.9% (average 18.1%) and MAE by 11.8–29.7% (average 22.0%) across five experimental distances. The results provide a preliminary reference for wavelength selection in multispectral LiDAR systems under simplified conditions. Full article

Rare-earth elements including the fifteen lanthanides, from lanthanum (La) to lutetium (Lu), together with scandium (Sc) and yttrium (Y), can act either as matrix cations or as active luminescent centers when incorporated into host lattices. Owing to their relatively large ionic radii, high coordination numbers, and structural stability, ions such as La, Lu, Sc, Y, and gadolinium (Gd) typically serve as matrix cations in rare-earth vanadate (REVO₄)-based phosphors, while other trivalent lanthanide (Ln³⁺) ions act as active luminescent centers. These REVO₄ phosphors have proved to be good host lattices for optically active Ln³⁺ ions giving strong luminescence assigned to absorption of the vanadate (VO₄³⁻) groups, and the efficient energy transfer between host lattice and Ln³⁺ ions. The unique electronic configuration of Ln³⁺ ions, particularly their unpaired 4f electrons, makes them ideal for applications in luminescence, magnetism, electronic and magnetic relaxation, and catalysis. Due to their complementary luminescent characteristics, Ln³⁺-doped REVO₄ phosphors have attracted significant attention in recent years. Their unique optical properties make them highly valuable across a broad spectrum of applications. This paper provides a comprehensive review of the state of the art in Ln³⁺ (Eu³⁺, Sm³⁺, Tm³⁺, Er³⁺, Ho³⁺, Tb³⁺, Nd³⁺, and Yb³⁺)-doped REVO₄ (RE = Y, Gd, Lu, La) phosphors. It examines current synthesis approaches, alongside the development of advanced strategies, and explores structural characteristics, innovative designs, and luminescent behavior, including both downconversion and upconversion processes and sensing applications, of the Ln³⁺-doped REVO₄ phosphors. Full article

Two-dimensional (2D) materials are promising candidates for nanoscale wear-protective coatings. The mechanisms governing their tribological behaviour (i.e., friction and wear) are material-dependent. In this work, we use atomistic molecular dynamics simulations to investigate nanoscale sliding, friction, and lithographic tracks in two 2D materials, graphene and MoS${}_2$, both placed on a SiO${}_2$ substrate. Our results reveal fundamentally different deformation mechanisms in the two materials, where deformation comes as a consequence of applied normal load. MoS${}_2$ deforms via the formation of a stable out-of-plane pucker beneath the contact, enabling efficient absorption and elastic redistribution of mechanical energy within the coating as well as simultaneous reduction of plastic deformation of the underlying material. Wear prevention in the substrate comes at the cost of localised damage to the MoS${}_2$ layer along the sliding path once it reaches the rupture point. On the contrary, graphene exhibits strongly localised deformation due to its high in-plane stiffness and atomic thickness, leading to plastic deformation of the underlying material and mitigating layer damage. These findings provide clear design guidelines for 2D coatings in nanotribological applications, and highlight layered materials, such as MoS${}_2$, as particularly effective for wear protection. Full article