Search Results (89)

Developing high-activity and high-durability Pd-based electrocatalysts is an important strategy to promote their commercial application. Herein, a smaller particle size and ultrathin sheet-like PdCu alloy metallene (PdCuene) were successfully prepared by using a one-pot wet chemistry method for FAOR. Experimental measurements indicated that the introduction Cu into Pd lattice induces a significant compressive strain effect through lattice mismatch between Pd and Cu, and the strain effect optimizes the electronic structure of Pd, as well as the high electrochemical surface area, increased exposure of active sites, and appropriate lattice strain have been demonstrated as factors that influence the enhancement of intrinsic activity and the acceleration of kinetics, thereby improving FAOR performance. Moreover, the stronger lattice strain of 0.85% would facilitate surface adsorption and dissociation of formic acid. Specifically, the optimized PdCuene exhibits enhanced mass activity and specific activity with current densities of 2.31 A mg_Pd⁻¹ and 4.09 mA cm⁻², respectively, which transcend the activities of Pd metallene (1.44 A mg_Pd⁻¹ and 2.73 mA cm⁻²) and commercial Pd/C (0.6 A mg_Pd⁻¹ and 1.53 mA cm⁻²). Meanwhile, PdCuene displayed obvious enhanced durability. The work provides an approach to modulate the lattice strain engineering, which represents a highly promising strategy for designing efficient FAOR electrocatalysts. Full article

The ice sheet and subglacial geological environment in Antarctica have become the focus of scientific exploration. The development of Antarctic drilling technology will serve as a crucial safeguard for scientific exploration. However, the extremely ultra-low temperatures and intricate geological conditions present substantial obstacles for drilling operations in Antarctica, and the existing drilling fluid technology cannot satisfy the requirements of efficient and safe drilling. To ameliorate the wettability and rheology of ultra-low-temperature drilling fluids, a new amide material (HAS) was prepared using dodecylamine polyoxyethylene ether, azelaic acid, and N-ethylethylenediamine as raw materials. Experiments using infrared spectroscopy, nuclear magnetic hydrogen spectroscopy, and contact angle indicated that the target product was successfully synthesized. Performance evaluation showed that 2% HAS could achieve a yield point of 2.5 Pa for drilling fluid at −55 °C, and it also gave the fluid superior shear-thinning characteristics and a large thixotropic loop area. This indicated that HAS significantly enhanced the rheological properties of the drilling fluid, ensuring that it can carry cuttings and ice debris. In addition, 2% HAS could also increase the colloidal rate from 8% to more than 76% at −55 °C in different base oils. Meanwhile, the colloid rate was maintained above 92.4% when the density was 0.92~0.95 g/cm³. Mechanism studies showed that HAS increased the zeta potential and decreased the particle size of organoclay. At the same time, it changed the organoclay state from a clustered state to a uniformly dispersed state, and the particle size decreased. It was found that HAS formed a weak gel grid structure through interactions between polar groups, such as amide and imino groups with organoclays particles, thus improving the rheology and wettability of drilling fluid. In addition, HAS is an environmentally friendly high-performance material. Full article

The design of photocatalysts capable of generating localized surface plasmon resonance (LSPR) effects represents a promising strategy for enhancing photocatalytic activity. However, the mechanistic role of plasmonic nanoparticles-induced interfacial electric fields in driving photocatalytic processes remains poorly understood. To produce a Schottky junction, varying amounts of Au nanoparticles widely utilized to broaden the light absorption were loaded onto ultrathin carbon nitride sheets (Au/UCN). The Au/UCN-20 Schottky junction exhibits exceptional photocatalytic activity, achieving a hydrogen evolution rate (14.2 mmol·g⁻¹ over a 4 h period) while maintaining robust stability through five consecutive photocatalytic cycles. The LSPR activity of Au nanoparticles are responsible for the broadened light absorption spectrum of Au/UCN nanocomposites. The interfacial electric field generated at the Au /UCN heterojunction is proposed to enhance charge-transfer efficiency through Schottky barrier penetration of photocarriers, mediated by electric field-driven carrier migration, according to surface potential and finite-difference time-domain (FDTD). These findings uncover a previously obscured photocatalytic mechanism driven by LSPR-induced interfacial electric fields, pioneering a quantum-dot-directed strategy to precisely engineer charge dynamics in advanced photocatalysts via targeted manipulation of nanoscale electric field effects. Full article

In this study, a laboratory-precision four-high micro-rolling mill was employed to investigate the influence of grain size on the deformation behavior and fracture mechanism of a micro-rolled Cu/Al composite ultra-thin sheet. Analytical testing techniques including scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM+EDS), X-ray diffraction (XRD), and unidirectional tensile experiments were utilized. The experimental results indicate that the grain size of the Cu/Al composite ultra-thin sheet increases with increasing annealing temperature and extended holding time while undergoing the first and second micro-rolling processes. Under identical annealing conditions, secondary micro-rolling leads to an increase in the grain size of Cu, while the growth rate of Al grains is reduced. Tensile tests and fracture surface observations reveal that as the annealing temperature increases, the grain size of the once-micro-rolled Cu/Al composite ultra-thin sheet also increases. When annealing at 400 °C for 40 min, the elongation reaches a maximum of 25.6%, with a tensile strength of 106.3 MPa. For the second micro-rolled samples, a maximum tensile strength of 114.8 MPa is achieved after annealing at a temperature of 360 °C for an 80 min holding time, although the elongation is significantly lower at 3.4%. This indicates that the fracture mode of the once-micro-rolled ultra-thin Cu/Al composite sheet is ductile fracture, whereas that of the second micro-rolled sample is brittle fracture. Full article

This work investigates the role of friction in the numerical prediction of formability for ultra-thin aluminum sheets made of the EN AW 8006-O alloy. Nakazima-type hemispherical punch stretching tests were conducted under lubricated conditions to assess the influence of interface tribology on thickness distribution and failure behavior. The experimental activity included tensile testing for material parameter identification and coefficient of friction (COF) measurements according to ASTM D1894 to characterize interface friction. These parameters were then implemented into a finite element model developed in PAM-STAMP. The simulation results were compared with experimental thickness profiles, and showed good agreement when calibrated friction coefficients were used. The analysis highlights the sensitivity of sheet deformation to frictional conditions, and demonstrates that accurate tribological input significantly improves predictive accuracy. The proposed workflow offers a reliable and efficient methodology for simulating forming processes involving ultra-thin aluminum foils, with potential applications in the food packaging industry. Full article

Graphene oxide (GO) films have attracted significant attention due to their potential in separation and filtration applications. Based on their unique lamellar structure and ultrathin nature, GO films are difficult to maintain in a free-standing form and typically require substrate support. Consequently, understanding their film formation behavior and mechanisms on substrates is of paramount importance. This work employs commonly used nonwoven fibrous membranes as substrates and guided by the coffee-ring theory, systematically investigates the film formation behaviors, film morphology, and underlying mechanisms of GO films on fibrous membranes with varying wettability. Fibrous membranes with different wetting properties—hydrophilic, hydrophobic, and superhydrophobic—were prepared via electrospinning and initiated chemical vapor deposition (iCVD) surface modification techniques. The spreading behaviors, deposition dynamics, capillary effects, and evaporation-induced film formation mechanisms of GO suspensions on these substrates were thoroughly examined. The results showed that GO formed belt-like, ring-like, and circular patterns on the three fibrous membranes, respectively. GO films encapsulated more than the upper half, approximately the upper half, and the top portion of fibers, respectively. Pronounced wrinkling of GO films was observed except for those on the hydrophilic fibrous membrane. This work demonstrates that tuning the wettability of fibrous substrates enables precise control over GO film morphology, including fiber encapsulation, wrinkling, and coverage area. Furthermore, it deepens the understanding of the interactions between 1D nanofibers and 2D GO sheets at low-dimensional scales, laying a foundational basis for the optimized design of membrane engineering. Full article

This study presents the development of a deep drawing process under an indirect hot stamping method for manufacturing an automotive internal combustion engine oil pan from ultra-high-strength steel (UHSS) sheets, specifically 22MnB5. The forming process involves two stages—cold stamping followed by hot stamping—and is finalized with rapid quenching to achieve a martensitic microstructure. Finite element simulation using AutoForm R8 was conducted to determine optimal forming conditions. The simulation results guided the design of the forming tools and were validated through experimental trials. The final oil pan component exhibited no cracks or wrinkles, with maximum thinning below 18%, a hardness of 550.63 HV, and a fully martensitic phase. This research demonstrates a novel and effective solution for producing deep-drawn, high-strength components using indirect hot stamping, contributing to the advancement of automotive forming processes in Thailand. Full article

Jointing is inevitable for CFRTP (carbon fiber reinforced thermoplastic) component applications in the automotive industry. In this study, commonly used jointing methods were applied to fasten CFRTP components. Three types of jointing methods. Ultrasonic welding, bolted joints, and adhesive joining, and three types of CFRTP materials, conventional cross-ply, ultra-thin prepreg cross-ply, and sheet molding compounds, were selected. The influence of the jointing methods on mechanical properties and damage patterns under bending load has been investigated. The finite element models were developed to predict the hazardous area and structural stiffness of jointed structures; the simulation results showed good agreement with experimental ones. The results indicate that the ultrasonic welding could reach similar bending stiffness compared to adhesive joining, whereas the stiffness of bolt jointed structures is relatively lower due to the contact separation induced by the bending deformation. Overall, the finite element model results correlated well with the experimental data. Full article

Micron-sized, ultrathin metal–organic framework (MOF) sheet is a two-dimensional (2D) hybrid material with a large specific surface area, which can be used not only in the fields of energy and biomedicine, but also in electrode modification to improve the electrochemical detection effect. In this work, the 2D-structured Co-TCPP(Fe) MOF sheets were synthesized from porphyrin molecules and cobalt ions and then combined with reduced graphene oxide (rGO) and perfluorosulfonic acid polymer (Nafion) solution to construct Co-TCPP(Fe)/rGO/Nafion-modified electrodes capable of sensitively capturing dopamine (DA). The 2D ultrathin lamellar structure of this electrode-modified material is beneficial to the formation of π-π stacking effect with DA molecules, and the oxygen-containing groups carried on its surface can also form electrostatic attraction with the amino groups of DA molecules. Therefore, the Co-TCPP(Fe)/rGO/Nafion-modified electrode under the synergistic effect shows a specific adsorption effect on DA molecules, resulting in high anti-interference ability and a low detection limit of 0.014 µM in the concentration range of 0.1–100 µM. Furthermore, the Co-TCPP(Fe)/rGO/Nafion composite material composed of micron-sized, ultrathin lamellar structures also shows high reusability due to the stability of its coordination structure and can demonstrate good results when applied to the actual sample detection of human urine. Full article

In this paper, we design an ultra-thin broadband transparent absorber based on indium tin oxide (ITO) film, and we choose polymethyl methacrylate (PMMA) high-transmittance dielectric sheet instead of the traditional dielectric sheet and polyethylene glycol terephthalate (PET) as the ITO film substrate. Simulation results indicate that the absorber achieves more than 90% absorption for positively incident electromagnetic waves in the broadband range of 5–21.15 GHz with a fractional bandwidth (FBW) of 123.5% and a thickness of 6.3 mm (0.105 λ_L, where λ_L is the wavelength at the lowest frequency). Meanwhile, this paper introduces the interference theory to explain the broadband absorption mechanism of the absorber, which makes up for the defect that the equivalent circuit model (ECM) method cannot analyze the oblique incidence electromagnetic wave. This paper also compares the HFSS simulation results, ECM theoretical values, and interference theoretical values under positively incident electromagnetic waves to clarify the advantages of interference theory in the design of wave absorbers. Full article

The recent fast advances in consumer electronics, especially in cell phones and displays, have led to the development of ultra-thin, hence flexible, glasses. Once available, such flexible glasses have proven to be of great interest and usefulness in other fields, too. Flexible photonics, for instance, has quickly taken advantage of this new material. At first sight, “flexible glass” appears to be an oxymoron. Glass is, by definition, fragile and highly breakable; its structure has puzzled scientists for decades, but it is evident that in most conditions it is a rigid material, so how can it bend? This possibility, however, has aroused the interest of artists and craftsmen since ancient times; thus, in Roman times the myth of flexible glass was born. Furthermore, the myth appeared again in the Middle Age, connected to a religious miracle. Today, however, flexible glass is no more a myth but a reality due to the fact that current technology permits us to produce micron-thick glass sheets, and any ultra-thin material can be bent. Flexibility is coming from the present capability to manufacture glass sheets at a tens of microns thickness coupled with the development of strengthening methods; it is also worth highlighting that, on the micrometric and nanometric scales, silicate glass presents plastic behavior. The most significant application area of flexible glass is consumer electronics, for the displays of smartphones and tablets, and for wearables, where flexibility and durability are crucial. Automotive and medical sectors are also gaining importance. A very relevant field, both for the market and the technological progress, is solar photovoltaics; mechanical flexibility and lightweight have allowed solar cells to evolve toward devices that possess the advantages of conformability, bendability, wearability, and moldability. The mature roll-to-roll manufacturing technology also allows for high-performance devices at a low cost. Here, a brief overview of the history of flexible glass and some examples of its application in solar photovoltaics are presented. Full article

Burgeoning two-dimensional (2D) materials provide more opportunities to overcome the shortcomings of silicon-based photodetectors. However, the inevitable carrier loss in the 2D material/Si heterojunction has seriously hindered further improvement in responsivity and detection speed. Here, we propose a graphene/PtSe₂/ultra-thin SiO₂/Si photodetector (PD) with multiple optimization mechanisms. Due to the fact that photo-generated carriers can travel in the graphene plane toward the Au electrode, the introduction of a top graphene contact with low sheet resistance provides a carrier collection path in the vertical direction and further restricts the carrier recombination behavior at the lateral grain boundary of PtSe₂ film. The ultra-thin SiO₂ passivation layer reduces the defects at the PtSe₂/Si heterojunction interface. As compared to the counterpart device without the graphene top contact, the responsivity, specific detectivity, and response speed of graphene/PtSe₂/ultra-thin SiO₂/Si PD under 808 nm illumination are improved to 0.572 A/W, 1.50 × 10¹¹ Jones, and 17.3/38.8 µs, respectively. The device can detect broad-spectrum optical signals as measured from 375 nm to 1550 nm under zero bias. The PD line array with 16-pixel units shows good near-infrared imaging ability at room temperature. Our study will provide guiding significance for how to improve the comprehensive properties of PDs based on 2D/Si heterostructure for practical applications. Full article

The development of advanced detection systems for charged particles in laser-based accelerators and the need for precise time of flight measurements have led to the creation of detectors using ultra-thin plastic scintillators, indicating their use as transmission detectors with low energy loss and minimal dispersion for protons around a few MeV. This study introduces a new detection system designed by the Institute for Instrumentation in Molecular Imaging for time of flight and timing applications at the National Accelerator Center in Seville. The system includes an ultra-thin EJ-214 plastic scintillator coupled with a photomultiplier tube and shielded by aluminized mylar sheets. The prototype installation as an external trigger system at the ion beam nuclear microprobe of the aforementioned facility, along with its temporal performance and ion transmission, was thoroughly characterized. Additionally, the scintillator thickness and uniformity were analyzed using Rutherford backscattering spectrometry. Results showed that the experimental thickness of the EJ-214 sheet differs by approximately 46% from the supplier specifications. The detector response to MeV protons demonstrates a strong dependence on the impact position but remains mostly linear with the applied working bias. Finally, single ion detection was successfully achieved, demonstrating the applicability of this new system as a diagnostic tool. Full article

The Chang 8 oil group within the Luo 1 well area of Jiyuan Oilfield, situated in the Ordos Basin, exemplifies an ultra-low-permeability reservoir with an average permeability of 0.84 mD. Despite primary development efforts through acid fracturing, suboptimal recovery efficiency has been observed due to inadequate injection–production matching. To mitigate this issue and enhance reservoir utilization, a comprehensive understanding of sand body architecture is imperative. This study employs a detailed reservoir architecture element analysis approach, integrating core samples, thin-section petrography, and geophysical logging data. The objective is to elucidate the internal structure and heterogeneity of sand bodies, which significantly influence hydrocarbon recovery. Key findings reveal that the study area is characterized by a shallow-water deltaic depositional system, featuring three principal sedimentary microfacies: subaqueous distributary channels, sheet sands, and lacustrine muds. Notably, subaqueous distributary channel sand bodies dominate, forming composite units via lateral accretion or vertical stacking of 2–5 individual channels, with widths exceeding 2000 m. Individual distributary channels range from 83 to 535 m in width, exhibiting both isolated and stacked contact styles. Importantly, only 25.97% of channels demonstrate connectivity, underscoring the critical role of channel scale and continuity in ultra-low-permeability reservoir development. By addressing the previously identified gap in architectural configuration knowledge, this study contributes foundational data for future development improvements. In conclusion, the detailed characterization of reservoir architecture offers pivotal insights into tailoring development strategies that align with the specific characteristics of ultra-low-permeability reservoirs, thereby improving overall recovery rates. Full article

The metal bipolar plate is a critical component of the hydrogen fuel cell stack used in proton exchange membrane fuel cells. Bipolar plates must have high accuracy micro-channels with a high aspect ratio (AR) between the channel depth and the half periodic width to achieve optimal cell performance. Conventional forming methods, such as micro-stamping, hydroforming, and rubber pad forming, cannot achieve these high ARs given that in these processes, material deformation is dominated by stretch deformation. In micro-roll forming the major deformation mode is bending, and this enables production of channels with higher ARs than is currently possible. However, micro-roll forming uses multiple sets of forming roll stands to form the part and this leads to technological challenges related to tool alignment and roll tool precision that must be overcome before widespread application can be achieved. This study presents a new methodology to achieve tight tool tolerances when producing micro-roll tooling by utilizing wire-EDM and micro-turning techniques. This is combined with a new micro-roll former design that enables high-precision tool alignment across multiple roll stations. Proof of concept is provided through micro-roll forming trials performed on ultra-thin titanium sheets that show that the proposed technology can achieve tight dimensional tolerances in the sub-millimeter scale that suits bipolar plate applications. Full article