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Catastrophic accidents caused by fatigue failures often occur in engineering structures. Thus, a fundamental understanding of cyclic-deformation and fatigue-failure mechanisms is critical for the development of fatigue-resistant structural materials. Here we report a high-entropy alloy with enhanced fatigue life by ductile-transformable multicomponent B2 precipitates. Its cyclic-deformation mechanisms are revealed by real-time in-situ neutron diffraction, transmission-electron microscopy, crystal-plasticity modeling, and Monte-Carlo simulations. Multiple cyclic-deformation mechanisms, including dislocation slips, precipitation strengthening, deformation twinning, and reversible martensitic phase transformation, are observed in the studied high-entropy alloy. Its improved fatigue performance at low strain amplitudes, i.e., the high fatigue-crack-initiation resistance, is attributed to the high elasticity, plastic deformability, and martensitic transformation of the B2-strengthening phase. This study shows that fatigue-resistant alloys can be developed by incorporating strengthening ductile-transformable multicomponent intermetallic phases. A fundamental understanding of fatigue-failure mechanisms is key to develop robust structural materials. Here the authors report a high entropy alloy with enhanced fatigue life by ductile transformable multicomponent B2 precipitates, as revealed by combined experimental and simulation methods.

Traditional calibration methods rely on the accurate localization of the chessboard points in images and their maximum likelihood estimation (MLE)-based optimization models implicitly require all detected points to have an identical uncertainty. The uncertainties of the detected control points are mainly determined by camera pose, the slant of the chessboard and the inconsistent imaging capabilities of the camera. The negative influence of the uncertainties that are induced by the two former factors can be eliminated by adequate data sampling. However, the last factor leads to the detected control points from some sensor areas having larger uncertainties than those from other sensor areas. This causes the final calibrated parameters to overfit the control points that are located at the poorer sensor areas. In this paper, we present a method for measuring the uncertainties of the detected control points and incorporating these measured uncertainties into the optimization model of the geometric calibration. The new model suppresses the influence from the control points with large uncertainties while amplifying the contributions from points with small uncertainties for the final convergence. We demonstrate the usability of the proposed method by first using eight cameras to collect a calibration dataset and then comparing our method to other recent works and the calibration module in OpenCV using that dataset.

Electrocatalysis provides a sustainable alternative route to produce nitrogen-containing molecules. However, poor carbon-nitrogen (C-N) coupling selectivity and limited current density pose challenges to its widespread adoption. Herein, we introduce a carbon-defect enhanced 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) mediated tandem process to tackle both problems. Our hetero-homogeneous system achieves a Faraday efficiency of ~99% with industrial-level current density of ~0.6 A·cm −2 for urotropine electrosynthesis. In situ near ambient pressure X-ray photoelectron spectroscopy and quasi in situ electron paramagnetic resonance reveal that the boosted activity originated from the oxidation of TEMPOH on the carbon defective sites, which accelerates the redox cycling of the molecular mediator for urotropine formation. This work highlights the catalytic effect of carbon defects on the redox cycling of TEMPO, improves both the selectivity and the rate of the electrocatalytic C-N coupling reaction, and offers insights for designing efficient electrochemical mediated oxidation processes and C-N coupling reactions. The authors demonstrate a TEMPO-mediated urotropine electrosynthesis that is accelerated by defective carbon, as the vacancy defects transfer the oxidation of TEMPOH from a sluggish outer sphere process into a rapid inner sphere mechanism via adsorption.

Atherosclerosis is characterized by the accumulation of lipids and deposition of fibrous elements in the vascular wall, which is the primary cause of cardiovascular diseases. Adenosine monophosphate-activated protein kinase (AMPK) is a metabolic sensor of energy metabolism that regulates multiple physiological processes, including lipid and glucose metabolism and the normalization of energy imbalances. Overwhelming evidence indicates that AMPK activation markedly attenuates atherosclerosis development. Autophagy inhibits cell apoptosis and inflammation and promotes cholesterol efflux and efferocytosis. Physiological autophagy is essential for maintaining normal cardiovascular function. Increasing evidence demonstrates that autophagy occurs in developing atherosclerotic plaques. Emerging evidence indicates that AMPK regulates autophagy via a downstream signaling pathway. The complex relationship between AMPK and autophagy has attracted the attention of many researchers because of this close relationship to atherosclerosis development. This review demonstrates the role of AMPK and autophagy in atherosclerosis. An improved understanding of this interrelationship will create novel preventive and therapeutic strategies for atherosclerosis.

Two-dimensional nanomaterials （2DNMs） have attracted increasing attention due to their unique properties and promising applications. Unlike 2DNMs with lamellar structures, metal ultrathin 2DNMs are difficult to synthesize and stabilize because they tend to form close-packed crystal structures. Most reported cases consist of monometallic and heterogeneous nanostructures. The synthesis of metal alloy 2DNMs has been rarely reported. Here, we report the synthesis of PdNi alloy wavy nanosheets （WNSs） using an enhanced CO-confinement strategy. This strategy is also suitable to the synthesis of other Pd-based alloy WNSs such as PdCu, PdFe, and even a trimetallic PdFeNi.

Magnesium alloys, being the lightest structural metals, have garnered significant attention in various fields. The characterization of inelastic behavior has been extensively investigated by researchers due to its impact on structural component performance. However, the occurrence of twinning in the absence of any applied driving force during unloading has lacked reasonable explanations. Moreover, the influence of deformation mechanisms other than twinning on inelastic behavior remains unclear. In this study, uniaxial tension and compression tests were conducted on hot-rolled magnesium alloy plates, and neutron diffraction experiments were employed to characterize the evolution of macroscopic mechanical response and microscopic mechanisms. Additionally, a twinning and detwinning (TDT) model based on the elastic visco-plastic self-consistent (EVPSC) model has been proposed, incorporating back stress to describe the deformation behavior during stress relaxation. This approach provides a comprehensive understanding of the inelastic behavior of magnesium alloys from multiple perspectives and captures the influence of microscale mechanisms. A thorough understanding of the inelastic behavior of magnesium alloys and a reasonable explanation for the occurrence of twinning under zero-stress conditions offer valuable insights for the precise design of magnesium alloy structures.

Within the lifecycle of a ship’s hull structure, damage due to collisions has been a focal point of research for researchers both domestically and internationally. To enhance the predictive accuracy of failure criteria in the simulation of ship hull collisions, this paper focuses on the modified Mohr–Coulomb (MMC) failure criterion for metals, utilizing a hybrid experimental–numerical method for parameter calibration. Consideration of stress-state-dependent mesh size sensitivity has been amended, and the approach is integrated into the comprehensive nonlinear finite element software Abaqus 2020. Finite element tensile simulations were conducted to validate the effectiveness of the MMC criterion. Simulation analyses were conducted based on drop hammer collision experiments with various failure criteria and grid sizes. The comparative validation highlighted the superiority of the mesh size sensitivity-corrected MMC failure criterion. The outcomes of this research provide a foundation for assessing the structural safety of ship hulls.

Tuning the crystal phase of alloy nanocrystals (NCs) offers an alternative way to improve their electrocatalytic performance, but, how heterometals diffuse and form ordered‐phase remains unclear. Herein, for the first time, the mechanism for forming tetrametallic ordered‐phase nanoplates (NPLs) is unraveled. The observations reveal that the intermetallic ordered‐phase nucleates through crystallinity alteration of the seeds and then propagates by reentrant grooves. Notably, the reentrant grooves act as intermediate NCs for ordered‐phase, eventually forming intermetallic PdCuIrCo NPLs. These NPLs substantially outperform for oxygen evolution reaction (221 mV at 10 mA cm−2) and hydrogen evolution reaction (19 mV at 10 mA cm−2) compared to commercial Ir/C and Pd/C catalysts in acidic media. For OER at 1.53 V versus RHE, the PdCuIrCo/C exhibits an enhanced mass activity of 9.8 A mg−1Pd+Ir (about ten times higher) than Ir/C. For HER at ‐0. 2 V versus RHE, PdCuIrCo/C shows a remarkable mass activity of 1.06 A mg−1Pd+Ir, which is three‐fold relative to Pd/C. These improvements can be ascribed to the intermetallic ordered‐structure with high‐valence Ir sites and tensile‐strain. This approach enabled the realization of a previously unobserved mechanism for ordered‐phase NCs. Therefore, this strategy of making ordered‐phase NPLs can be used in diverse heterogeneous catalysis. By the utilization of crystallinity of the seeds and intermediate nanocrystals, ordered phase PdCuIr and PdCuIrCo nanoplates are obtained. These nanoplates outperform for oxygen evolution reaction and hydrogen evolution reaction compared to Ir/C and Pd/C catalysts in acidic media.

Chlorine (Cl 2 ) is one of the most important chemicals produced by the electrolysis of brine solutions and is a key raw material for many areas of industrial chemistry. For nearly half a century, dimensionally stable anode (DSA) made from a mixture of RuO 2 and TiO 2 solid oxides coated on Ti substrate has been the most widely used electrode for chlorine evolution reaction (CER). In harsh operating environments, the stability of DSAs remains a major challenge greatly affecting their lifetime. The deactivation of DSAs significantly increases the cost of the chlor-alkali industry due to the corrosion of Ru and the formation of the passivation layer TiO 2 . Therefore, it is urgent to develop catalysts with higher activity and stability, which requires a thorough understanding of the deactivation mechanism of DSA catalysts. This paper reviews existing references on the deactivation mechanisms of DSA catalysts, including both experimental and theoretical studies. Studies on how CER selectivity affects electrode stability are also discussed. Furthermore, studies on the effects of the preparation process, elemental composition, and surface/interface structures on the DSA stability and corresponding improvement strategies are summarized. The development of other non-DSA-type catalysts with comparable stability is also reviewed, and future opportunities in this exciting field are also outlined.

Electrolytic water splitting by renewable energy is a technology with great potential for producing hydrogen (H 2 ) without carbon emission, but this technical route is hindered by its huge energy (electricity) cost, which is mainly wasted by the anode oxygen evolution reaction (OER) while the value of the anode product (oxygen) is very limited. Replacing the high-energy-cost OER with a selective organic compound electrooxidation carried out at a relatively lower potential can reduce the electricity cost while producing value-added chemicals. Currently, H 2 generation coupled with synthesis of value-added organic compounds faces the challenge of low selectivity and slow generation rate of the anodic products. One-dimensional (1-D) nanocatalysts with a unique morphology, well-defined active sites, and good electron conductivity have shown excellent performance in many electrocatalytic reactions. The rational design and regulation of 1-D nanocatalysts through surface engineering can optimize the adsorption energy of intermediate molecules and improve the selectivity of organic electrooxidation reactions. Herein, we summarized the recent research progress of 1-D nanocatalysts applied in different organic electrooxidation reactions and introduced several different fabrication strategies for surface engineering of 1-D nanocatalysts. Then, we focused on the relationship between surface engineering and the selectivity of organic electrooxidation reaction products. Finally, future challenges and development prospects of 1-D nanocatalysts in the coupled system consisting of organic electrooxidation and hydrogen evolution reactions are briefly outlined.