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Microstructural evolution in 3D: An existence result

Nonlinear Analysis, Theory, Methods and Applications 2025年 258卷

作者： Kinderlehrer, David Yun, KiHyun Center for Nonlinear Analysis Department of Mathematical Sciences and Materials Research Science and Engineering Center Carnegie Mellon University PittsburghPA15213 United States Department of Mathematics Hankuk University of Foreign Studies Youngin-si Gyeonggi-do449-791 Korea Republic of

Microstructural coarsening is a network of grains separated by interfaces, facets, that evolve by generalized curvature. The facets meet along curves that come together at points. Systems of this nature consist of many nonlinear PDEs with their boundary conditions. Here we explore the local in time existence for a configuration, perhaps the simplest, close to a known equilibrium configuration. © 2025 The Authors

关键词： Microstructural evolution

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Stability and activity of nickel catalysts supported on diatomite for dry reforming of methane: Role of cerium and boron promoters

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Journal of the Energy Institute 2025年 120卷

作者： Azevedo, Amanda L. Melo, Dulce M.A. Silva, Yuri K.R.O. Oliveira, Ângelo A.S. Favacho, Vanessa S.S. Souza, Lalyson M.L.R. Rocha, Amanda R.C.C. Braga, Renata M. Postgraduate Program in Chemistry Federal University of Rio Grande do Norte Natal Brazil Postgraduate Program in Materials Science and Engineering Federal University of Rio Grande do Norte Natal Brazil Postgraduate Program in Petroleum Science and Engineering Federal University of Rio Grande Do Norte Natal Brazil Agricultural School of Jundiaí Federal University of Rio Grande do Norte RN Macaíba Brazil

This study evaluates the activity and stability of nickel-based catalysts supported on diatomite and promoted with 1 or 2 wt% of cerium or boron for the dry reforming of methane (DRM). Diatomite, a naturally abundant and low-cost support, requires no complex synthesis procedures and remains relatively underexplored in DRM applications. Given the economic viability of using this material, the incorporation of promoters such as cerium and boron can enhance its catalytic properties, including resistance to coke formation, thermal stability, and activity at both low and high temperatures, thereby increasing its potential for industrial application. The support composition was analyzed by X-ray fluorescence (XRF), and its morphology was examined using scanning electron microscopy (SEM). The catalysts were characterized by SEM, X-ray diffraction (XRD), nitrogen physisorption, H2 temperature-programmed reduction (H2-TPR), thermogravimetric analysis (TGA), and Raman spectroscopy. The catalytic performance results indicated that cerium addition enhanced CO2 and CH4 conversion, with 2 wt% Ce-promoted catalyst stands out due to its significantly higher conversion rates and lower coke formation, as observed in TGA. The 2 wt% boron-promoted catalyst exhibited greater stability, with significant resistance to coke formation, despite showing lower CH4 conversion. SEM analysis revealed the presence of carbon filaments, particularly in the catalysts without boron, whereas boron-promoted catalysts showed reduced filamentous carbon formation. The activation energies derived from the Arrhenius plot further corroborate these findings, demonstrating that boron-promoted catalysts exhibited satisfactory performance at high temperatures (>800 °C), where the reaction is thermodynamically controlled. In turn, cerium-promoted catalysts achieved superior catalytic performance at ≤ 700 °C and performed similarly to boron-containing catalysts at higher temperatures. Therefore, both promoters impa

关键词： Thermogravimetric analysis

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High-Performance Silicon Anodes Enabled by Multifunctional Ultrafine Silica Nanoparticle-Embedded Carbon Coatings for Lithium-Ion Batteries

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Advanced Energy materials 2025年第0期

作者： Sun, Zhefei Yin, Quanzhi Zhou, Shenghui Chen, Haoyu Wen, Sifan Yang, Huiping Wu, Xiaoyu Pan, Jianhai Han, Jiajia Yang, Hui Zhuang, Zilong Feng, Shijie Zhang, Li Peng, Dong-Liang Zhang, Qiaobao State Key Laboratory of Physical Chemistry of Solid Surfaces College of Materials Xiamen University Xiamen361005 China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Tan Kah Kee Innovation Laboratory Collaborative Innovation Center of Chemistry for Energy Materials Xiamen University Fujian Xiamen361005 China State Key Laboratory of Material Processing and Die & Mould Technology Department of Mechanics School of Aerospace Engineering Huazhong University of Science and Technology Hubei Wuhan430074 China Department of Mechanical Engineering University of Wisconsin-Madison MadisonWI53706 United States Materials Science and Engineering Program University of California San Diego La JollaCA92093 United States Longmen Laboratory Henan Luoyang471023 China

Silicon (Si) holds immense promise as viable anode for next-generation high-energy-density Li-ion batteries (LIBs). However, its poor ionic/electronic conductivity and significant volumetric changes during cycling lead to rapidly deteriorated LIB performance. Here, a novel multifunctional coating featuring ultrafine SiO2 nanoparticles (2-C) to resolve these challenges is proposed. This unique uSiO2-C coating provides high-efficient electron and ion transport pathways, while also improves interfacial stability and mitigates volume changes during cycling, thereby enhancing the conductivity and structural integrity of Si@uSiO2-C, as corroborated by extensive experimental and computational studies. In addition, the abundant interfaces in uSiO2-C coating facilitate Li+ transport and the evenly distributed ultrafine SiO2 nanoparticles impart high electrochemical reactivity and mechanical robustness. Consequently, the Si@uSiO2-C anode achieves a high reversible capacity of 2093 mAh g−1 at 0.2 A g−1, with a high initial Coulombic efficiency of 88.3%, superior rate capability and durability (1000 cycles, 928 mAh g−1 at 1.0 A g−1, 75% capacity retention). Full cells paired with commercial LiFePO4 cathodes demonstrate high cyclability, maintaining 80% capacity retention over 500 cycles at 4 C. This work highlights the vital role of multifunctional coating in promoting the electrochemical performance of Si-based anodes for high-performance LIBs. © 2025 Wiley-VCH GmbH.

关键词： SiO2 nanoparticles

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Polarization switching in ferroelectric HfO2 from first-principles lattice mode analysis

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Physical Review B 2025年第13期111卷 134106-134106页

作者： Yubo Qi Sobhit Singh Karin M. Rabe Department of Physics University of Alabama at Birmingham Birmingham Alabama 35294 USA Department of Mechanical Engineering University of Rochester Rochester New York 14627 USA Materials Science Program University of Rochester Rochester New York 14627 USA Department of Physics and Astronomy Rutgers University Piscataway New Jersey 08854 USA

In this paper, we introduce a first-principles-based lattice mode analysis method to investigate the competition between different polarization switching paths in HfO2. Because the stability of the polar orthorhombic Pca21 phase of HfO2 arises from a trilinear coupling, polarization switching requires the flipping of not only the polar Γ15Z mode, but also at least one zone-boundary antipolar mode. This means that each polarization state has multiple variants, leading to multiple possible switching paths connecting up- and down-polarized states, which can be systemically enumerated within this framework for efficient identification of the optimal switching path. Our lattice mode analysis also explains why the activation energy of propagation of the most widely studied domain-wall structure in HfO2, which requires the reversal of the X2− mode, is much larger than that of propagation of domain-wall structures with a uniform sign for the X2− mode. This approach deepens our understanding of distinctive properties of ferroelectric HfO2 related to polarization switching and domain-wall motion, including sluggish domain-wall motion, robust ferroelectricity in thin films, and the observation that the antipolar Pbca phase can hardly be transformed to the ferroelectric Pca21 phase by an electric field. Our mode analysis method can be more generally applied to any improper or hybrid improper ferroelectric, in which polarization switching requires changes of nonpolar distortions, for systematic and efficient prediction of optimal switching paths and estimation of coercive fields.

关键词： Ferroelectricity

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Optimal sandwich panel's core design for an enhanced impact resistance

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Heliyon 2025年第1期11卷 e41211页

作者： Charkaoui, Assil Hassan, Noha M. Bahroun, Zied Materials Science and Engineering Program College of Arts and Sciences American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates Department of Industrial Engineering College of Engineering American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates

Despite the extensive literature revealing various core structures that can enhance the impact resistance of composite panels, a comparative study illustrating the difference in performance of the various cores under same loading conditions is missing. The aim of this study is to determine the optimal core structure and design in terms of energy absorption under low-velocity impact using both numerical simulations and experimental testing for validation. Response surface analysis was used to design the experiments and analyse the panel's behaviour. A total of 160 numerical simulations were conducted by varying the core shape, density, number of layers and panel's thickness. Drop tower tests were performed to experimentally validate the results. Additive manufacturing was used to 3D print the tested structures which simplified the manufacturing process. Results provided insights on time to perforation, stiffness of the panels showcasing an inverse relationship between recoverable strain energy and equivalent plastic strain. The number of layers within the panels were identified as a pivotal factor in the energy distribution and tendency for localized plastic deformation to occur. Both numerical and experimental results revealed the superior energy absorption capabilities of the X-frame core shaped structure. Regression models developed shed light on the relationships between core height, volume fraction, number of layers, and core topology revealing the extent of damage. Multi-objective optimization was used to yield optimal configuration for sandwich panels with highest impact resistance. © 2024

关键词： Additive manufacturing Core geometry Energy absorption Impact resistance Optimization Sandwich panels

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Unavoidable multilevel biaxial symmetry breaking in chiral hybrid liquid crystals

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Physical Review E 2025年第4期111卷 045410-045410页

作者： Jin-Sheng Wu Marina Torres Lázaro Souvik Ghosh Haridas Mundoor Henricus H. Wensink Ivan I. Smalyukh Department of Physics and Chemical Physics Program University of Colorado Boulder Colorado 80309 USA Laboratoire de Physique des Solides–UMR 8502 Université Paris-Saclay and CNRS 91405 Orsay France International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashihiroshima Japan Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado Boulder Colorado 80309 USA

Chiral nematic or cholesteric liquid crystals (LCs) are fluid mesophases with long-ranged orientational order featuring a quasilayered periodicity imparted by a helical director configuration but lacking long-range positional order. Doping molecular cholesteric LCs with strongly anisotropic uniaxial colloidal particles adds another level of complexity because of the interplay between weak surface-anchoring boundary conditions and bulk-based elastic distortions near the particle-LC interface. Using cylindrical colloidal disks and rods with different geometric shapes and surface conditions, we demonstrate that these colloidal inclusions generically exhibit biaxial orientational probability distributions which may impart anomalously strong local biaxiality onto the hybrid cholesteric LC structure. Unlike nonchiral hybrid molecular-colloidal LCs, where biaxial order emerges only at critical colloid volume fractions exceeding some uniaxial-biaxial transition value, the orientational probability of the colloidal inclusions immersed in chiral nematic hosts is unambiguously biaxial even at infinite dilution. We demonstrate that the colloids induce local biaxial perturbations within the molecular orientational order of the LC host medium which strongly enhances the weak but native biaxial order of chiral nematic LC induced by the chiral symmetry breaking of the director field. With the help of analytical modeling and computer simulations based on the Landau–de Gennes free energy of the host LC around the colloids, we rationalize the observed multilevel biaxial order and conclude that it is not only unavoidable but also strongly enhanced compared to both achiral hybrid LCs and purely molecular cholesteric LCs.

关键词： Cholesteric liquid crystals

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Dangling bonds and asymmetric charge redistribution triggered by grain boundary for improved photocatalytic CO2 reduction and ammonia synthesis

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Chemical engineering science 2025年 314卷

作者： Shao, Zhiwei Ye, Caichao Xiong, Jun Li, Ang Jiang, Wei Di, Jun School of Chemistry and Chemical Engineering National Special Superfine Powder Engineering Research Center Nanjing University of Science and Technology Nanjing210094 China Academy for Advanced Interdisciplinary Studies & Department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen518055 China Institute for Energy Research Jiangsu University Zhenjiang212013 China MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing Nanjing University of Science and Technology Jiangsu Nanjing210094 China

The role of grain boundaries in photocatalysis is still an open question. In this work, a generic crystal-induced re-growth strategy is developed to engineer grain boundaries into various 2D atomic layers to boost the photocatalytic activity. Take Bi24O31Br10(BOB) as an example, the engineered grain boundaries will lead to the generation of asymmetric charge redistributed interface, and work as quantum well to promote the oriented charge separation. Meantime, the grain boundaries will provide active electronic states with abundant dangling bonds to strengthen molecular interaction, and further optimize intermediate conversion. Benefiting from these advantages, the grain boundaries-rich BOB (BOB-GB) display a good CO2 photoreduction rate to yield CO (61.34 μmol g−1h−1), 5.4 and 95.9 times higher than BOB and bulk BOB, respectively. Moreover, it delivers an excellent NH3 generation rate of 13,620 μmol g−1h−1, with apparent quantum efficiencies of 43.0 %, 30.7 % at 380, 400 nm, respectively. © 2025 Elsevier Ltd

关键词： Photocatalytic activity

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Exploring the energy landscape of aluminas through machine learning interatomic potential

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Physical Review materials 2025年第2期9卷 023801-023801页

作者： Lei Zhang Wenhao Luo Renxi Liu Mohan Chen Zhongbo Yan Kun Cao Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices State Key Laboratory of Optoelectronic Materials and Technologies Center for Neutron Science and Technology School of Physics Sun Yat-Sen University Guangzhou 510275 China HEDPS CAPT College of Engineering Peking University Beijing 100871 China Academy for Advanced Interdisciplinary Studies Peking University Beijing 90871 China AI for Science Institute Beijing 100080 China

Aluminum oxide (alumina, Al2O3) exists in various structures and has broad industrial applications. While the crystal structure of α−Al2O3 is well-established, those of transitional aluminas remain highly debated. In this study, we propose a universal machine learning interatomic potential (MLIP) for aluminas, trained using the neuroevolution potential (NEP) approach. The dataset is constructed through iterative training and farthest point sampling, ensuring the generation of the most representative configurations for an exhaustive sampling of the potential energy surface. The accuracy and generality of the potential are validated through simulations under a wide range of conditions, including high temperatures and pressures. A phase diagram is presented that includes both transitional aluminas and α−Al2O3 based on the NEP. We also successfully extrapolate the phase diagram of aluminas under extreme conditions ([0, 4000] K and [0, 200] GPa ranges of temperature and pressure, respectively), while maintaining high accuracy in describing their properties under more moderate conditions. Furthermore, combined with our developed structure search workflow, the NEP provides an evaluation of existing γ−Al2O3 structure models. The NEP developed in this work enables highly accurate dynamic simulations of various aluminas on larger scales and longer timescales, while also offering new insights into the study of transitional aluminas structures.

关键词： Aluminum oxide

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Enhancing Power Factor in n-type Chalcopyrite CdSnAs₂ Thermoelectrics via Supercooled Solidification

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ACS Applied Energy materials 2025年

作者： Kishida, Shoki Okamoto, Norihiko L. Katsube, Ryoji Nagaoka, Akira Sumiyoshi, Isshin Nishioka, Kensuke Ichitsubo, Tetsu Nose, Yoshitaro Department of Materials Science and Engineering Kyoto University Kyoto 606-8501 Japan Institute for Materials Research Tohoku University Sendai 980-8577 Japan Department of Materials Process Engineering Nagoya University Nagoya 464-8603 Japan Electrical and Electronic Engineering Program University of Miyazaki Miyazaki 889-2192 Japan GX Research Center University of Miyazaki Miyazaki 889-2192 Japan

The practical application of thermoelectric (TE) materials is often limited by the relatively underdeveloped performance of n-type materials compared to their p-type counterparts. Chalcopyrite CdSnAs₂ is a promising n-type semiconductor for thermoelectric applications owing to its narrow bandgap around 0.3 eV and exceptionally high electron mobility of 10³-10⁴ cm² V^-1 s^-1. In this study, we investigated the crystal growth, microstructure, and thermoelectric properties of CdSnAs₂. Contrary to conventional understanding of unidirectional melt growth, CdSnAs₂ samples grown at higher cooling rates exhibited better crystallinity, whereas some cracks were observed in those cooled more slowly. Thermal analyses revealed that a phase transition from sphalerite to chalcopyrite occurred after solidification in slowly cooled samples, resulting in the formation of dislocations and cracks due to lattice mismatch between the phases. In contrast, rapid cooling induced supercooling, which lowered the solidification temperature and enabled the phase transition to occur in the presence of a residual liquid phase, thereby leading to a more favorable microstructure. As a result, the sample grown at the highest cooling rate (7.6 K min^-1) achieved an ultrahigh power factor of 3180 μW m^-1 K^-2 at 600 K and a peak ZT of 0.59 at 682 K. The power factor of CdSnAs₂ surpasses that of conventional binary n-type TE materials such as SnSe and PbTe, underscoring its strong potential for intermediate-temperature thermoelectric applications. © 2025 American Chemical Society.

关键词： energy harvesting n-type thermoelectrics solid−solid phase transition supercooling thermal analysis ultrahigh mobility

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The effects of dynamic dwell time systems on the usability of eye-tracking technology: a systematic review and meta-analyses

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Human-Computer Interaction 2025年

作者： Burnham, Seamus P. L. Bonar, Sonja Collins, Mackenzie Davies, T. Claire Department of Mechanical and Materials Engineering Faculty of Engineering and Applied Science Queen’s University Kingston Canada The Centre for Neuroscience Studies Queen’s University Kingston Canada School of Medicine Faculty of Health Sciences Queen’s University Kingston Canada

Eye-tracking can be used by individuals with severe motor impairments as a hands-free access method to computer systems. The traditional eye-tracking selection method employs static dwell times that are held constant throughout a task. The value of this parameter has an inherent speed-accuracy trade-off, with long dwell times being accurate but slow, and short dwell times being efficient but error-prone. To address this usability flaw, emerging research has introduced dynamic dwell time systems that employ either the user or a computer algorithm to vary the dwell time parameter throughout the task. A systematic review was undertaken to determine the modes and mechanisms of dwell time manipulation employed by these dynamic systems and the computer-based tasks they support. From six academic databases, 2765 relevant studies were identified. After removal of duplicates, title and abstract screening, and full text screening, four journal articles and eight conference proceedings evaluated dynamic dwell time systems. A series of fixed elements meta-analyses showed that the dynamic dwell time systems were significantly more usable than their static dwell time comparators. Dynamic systems may mitigate the speed-accuracy trade-offs associated with static dwell times. Future research required to further increase the usability of these systems is discussed. © 2025 The Author(s). Published with license by Taylor & Francis Group, LLC.

关键词： Usability engineering

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