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arXiv 2025年

作者： Allison, Katherine Kelly, Jonathan Hatton, Benjamin STARS Laboratory University of Toronto Institute for Aerospace Studies University of Toronto ON Canada Bio-Inspired Materials & Design Laboratory Department of Materials Science & Engineering University of Toronto ON Canada

Grip surfaces with tunable friction can actively modify contact conditions, enabling transitions between higher- and lower-friction states for grasp adjustment. Friction can be increased to grip securely and then decreased to gently release (e.g., for handovers) or manipulate in-hand. Recent friction-tuning surface designs using soft pneumatic chambers show good control over grip friction;however, most require complex fabrication processes and/or custom gripper hardware. We present a practical structured fingerpad design for friction tuning that uses less than $1 USD of materials, takes only seconds to repair, and is easily adapted to existing grippers. Our design uses surface morphology changes to tune friction. The fingerpad is actuated by pressurizing its internal chambers, thereby deflecting its flexible grip surface out from or into these chambers. We characterize the friction-tuning capabilities of our design by measuring the shear force required to pull an object from a gripper equipped with two independently actuated fingerpads. Our results show that varying actuation pressure and timing changes the magnitude of friction forces on a gripped object by up to a factor of 2.8. We demonstrate additional features including macro-scale interlocking behaviour and pressure-based object detection. Copyright © 2025, The Authors. All rights reserved.

关键词： Grippers

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High-Strength D2 tool steel via material extrusion additive manufacturing and post-heat treatment

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materials and Design 2025年 254卷

作者： Jeon, Min-Su Park, So-Yeon Cho, Yong-Hoon Baek, Michelle Kim, Hyoung Seop Lee, Kee-Ahn Department of materials Science and engineering Inha University Incheon22212 Cuba Program in Semiconductor Convergence Inha University Incheon22212 Cuba Markforged Seongnam-si13201 Cuba Department of Materials Science and Engineering Pohang University of Science and Technology Pohang-si 37673 Cuba

AISI D2 tool steel was fabricated using metal-materials extrusion additive manufacturing (M−MEX), followed by heat treatment to optimize its microstructure and mechanical properties. These were compared with conventional wrought D2 materials. The as-sintered M−MEX D2 showed a pearlite matrix with a higher fraction of low-angle boundaries and developed substructures, in contrast to the fully ferrite matrix of the as-fabricated wrought D2. MEX D2 also retained near-spherical carbides (2–5 μm), evenly distributed as in the starting powder, whereas wrought D2 contained coarse carbides exceeding 5 μm, often reaching tens of μm. After heat treatment, both materials transformed into fully lath martensite with sub-micron carbide precipitation. Heat-treated MEX D2 achieved a tensile strength of ∼ 2.09 GPa and elongation of 1.27 %, representing a 15.5 % increase in strength and 170 % increase in elongation compared to heat-treated wrought D2 (1.81 GPa and 0.47 %). Fractography revealed extensive carbide fracture in wrought D2, whereas MEX D2 exhibited limited carbide cracking, with matrix substructure dominating the fracture surface. These results demonstrate that the M−MEX process, combined with heat treatment, yields finer carbides, reduced carbide cracking, and significantly improved mechanical performance, highlighting its potential as a superior manufacturing route for high-strength D2 tool steel. © 2025 The Authors

关键词： Tensile strength

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Resolving Contradictory Estimates of Band Gaps of Bulk PdSe2: A Wannier-Localized Optimally-Tuned Screened Range-Separated Hybrid Density Functional Theory Study

arXiv

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arXiv 2025年

作者： Florio, Fred Camarasa-Gómez, María Ohad, Guy Naveh, Doron Kronik, Leeor Ramasubramaniam, Ashwin Department of Mechanical and Industrial Engineering University of Massachusetts Amherst AmherstMA01003 United States Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovoth7610001 Israel Institute for Nanotechnology and Advanced Materials Bar-Ilan University Ramat Gan52900 Israel Materials Science and Engineering Graduate Program University of Massachusetts Amherst AmherstMA01003 United States

Palladium diselenide (PdSe2)—a layered van der Waals material—is attracting significant attention for optoelectronics due to the wide tunability of its band gap from the infrared through the visible range as a function of the number of layers. However, there continues to be disagreement over the precise nature and value of the optical band gap of bulk PdSe2, owing to the rather small value of this gap that complicates experimental measurements and their interpretation. Here, we design and employ a Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional to investigate the electronic bandstructures and optical absorption spectra of bulk and monolayer PdSe2. In particular, we account carefully for the finite exciton center-of-mass momentum within a time-dependent WOT-SRSH framework to calculate the indirect optical gap and absorption onset accurately. Our results agree well with the best available photoconductivity measurements, as well as with state-of-the-art many-body perturbation theory calculations, confirming that bulk PdSe2 has an optical gap in the mid-infrared (upper-bound of 0.44 eV). More generally, this work further bolsters the utility of the WOT-SRSH approach for predictive modeling of layered semiconductors. Copyright © 2025, The Authors. All rights reserved.

关键词： Layered semiconductors

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High-performance UV polarization sensitive photodetector for a graphene(2D)/GaN(3D) junction with a non-centrosymmetric electric field

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Photonics Research 2025年第6期13卷 1544-1553页

作者： Can Zou Qing Liu Lu Zhang Xiao Tang Xiaohang Li Shuti Li Fangliang Gao Guangdong Engineering Research Center of Optoelectronic Functional Materials and Devices School of Electronic Science and Engineering (School of Microelectronics) South China Normal University Guangzhou 510631 China Advanced Semiconductor Laboratory Electrical and Computer Engineering Program CEMSE Division King Abdullah University of Science and Technology Thuwal 239556900 Saudi Arabia e-mail: lishuti@*** e-mail: gaofl@m.***

This study pioneers a high-performance UV polarization-sensitive photodetector by ingeniously integrating non-centrosymmetric metal nanostructures into a graphene ( Gr ) / Al 2 O 3 / GaN heterojunction. Unlike conventional approaches constrained by graphene’s intrinsic isotropy or complex nanoscale patterning, our design introduces asymmetric metal architectures (E-/T-type) to artificially create directional anisotropy. These structures generate plasmon-enhanced localized electric fields that selectively amplify photogenerated carrier momentum under polarized UV light (325 nm), synergized with Fowler-Nordheim tunneling (FNT) across an atomically thin Al 2 O 3 barrier. The result is a breakthrough in performance: a record anisotropy ratio of 115.5 (E-type, − 2 V ) and exceptional responsivity (97.7 A/W), surpassing existing graphene-based detectors by over an order of magnitude. Crucially, by systematically modulating metal geometry and density, we demonstrate a universal platform adaptable to diverse 2D/3D systems. This study provides a valuable reference for developing and practically applying photodetectors with higher anisotropy than ultraviolet polarization sensitivity.

关键词： Chemical vapor deposition Metals Nanostructures Quantum efficiency Surface plasmon resonance X-ray diffraction

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A novel approach to fabricating SUS 316L steel foam using material extrusion additive manufacturing technology

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Journal of materials Research and Technology 2025年 36卷 8219-8229页

作者： Noh-Geon Song So-Yeon Park Jung-Yeul Yun Ju-Yong Kim Kee-Ahn Lee Department of Materials Science and Engineering Inha University Incheon 22212 Republic of Korea Program in Semiconductor Convergence Inha University Incheon 22212 Republic of Korea Metal Powder Department Korea Institute of Materials Science Changwon 51508 Republic of Korea Reprotech Suwon-si 16229 Gyeonggi-do Republic of Korea

This study introduces a novel method for manufacturing porous SUS316L using the metal material extrusion (MEX) process and examines the effects of the powder particle size on the pore structure, gas flowability, and mechanical properties. SUS316L foams were fabricated using powders with average sizes of 50 μm and 8 μm. Open pore diameters were approximately 10 μm for the 50 μm foam and 2 μm for the 8 μm foam. Gas flowability measurements revealed that the 50 μm foam exhibited slope values suitable for filtration applications, whereas the 8 μm foam showed lower flowability due to a reduced pore fraction and size. Compressive testing indicated yield strengths of 82.57 MPa and 141.33 MPa for the 50 μm and 8 μm foams, respectively, demonstrating superior strength-to-weight ratios compared to SUS316L foams fabricated by conventional methods and surpassing the mechanical performance of commercial 316L filters manufactured by powder metallurgy process. These findings highlight the capability of MEX in producing porous SUS316L structures with tunable pores and mechanical properties for various applications.

关键词： Material extrusion additive manufacturing 316L stainless steel Foam Compressive property Gas flowability

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Synergetic effects of multiple junction and surface hydroxyl in Cu/CuO/Cu2O/TiO2 heterostructures towards highly efficient photocatalysts for hydrogen generation

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materials science for Energy Technologies 2025年 8卷 131-142页

作者： Subagyo, Riki Anindika, Garcelina Rizky Aufkani, Afif Akmal Zhang, Lei Ardhyananta, Hosta Burhan, R.Y. Perry Nugraheni, Zjahra Vianita Akhlus, Syafsir Bahruji, Hasliza Prasetyoko, Didik Wellia, Diana Vanda Ivansyah, Atthar Luqman Arramel Kusumawati, Yuly Department of Chemistry Faculty of Science and Analytic Data Institut Teknologi Sepuluh Nopember Surabaya60111 Indonesia Center of Excellence Applied Physics and Chemistry Nano Center Indonesia Jl PUSPIPTEK South Tangerang Banten15314 Indonesia Department of Physics National University of Singapore Singapore117551 Singapore Department of Materials and Metallurgical Engineering Faculty of Industrial Technology and Systems Engineering Institut Teknologi Sepuluh Nopember Surabaya60111 Indonesia Centre of Advanced Material and Energy Science Universiti Brunei Darussalam Jalan Tungku Link BE 1410 Brunei Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Andalas Padang25163 Indonesia Master Program in Computational Science Faculty of Mathematics and Natural Science Institut Teknologi Bandung Jalan Ganesha No. 10 Bandung40132 Indonesia Instrumentation and Computational Physics Research Group Department of Physics Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha No.10 West Java Bandung40132 Indonesia

The implementation of titanium dioxide (TiO2) as a photocatalyst material in hydrogen (H2) evolution reaction (HER) has embarked renewed interest in the past decade. Rapid electron-hole pairs recombination and wide band gap of a photo-sensitive material of TiO2 are detrimental toward the targeted catalytical reaction. In this study, we present the rational design, fabrication, photocatalytic performance of TiO2-Cu/CuO/Cu2O heterostructures (CuTi) using viable chemical reduction method. The Z-scheme and S-scheme are succesfully generated across the TiO2/CuO/Cu2O interfaces, while the Schottky junction arises on the Cu perimeters. This is evidenced from the blue shifted about 0.3 eV of Cu 2p core level determined by using X-ray photoemission spectroscopy (XPS), in combination with the formation of inverse V-shape of the Mott-Schottky plots. In addition, we find that Cu/CuO/Cu2O facilitates photon absorption range up to the visible region. The multiple heterojunction and the large number of OHsurface enhanced charge carrier transfer are associated to the suppression of photoluminescence (PL) intensity, high surface hydroxyl (OHsurface) density in CuTi probed by XPS, and fast electron transfer based on the electrochemical measurements. The presence of OHsurface inhibits the recombination of electron. A significant H2 photogeneration rate enhancement is achieved when an optimized 5 wt% Cu/CuO/Cu2O concentration is used on TiO2 to achieve 7,157.19 μmol·g−1 (1,789.30 μmol·g−1·h−1). Based on this finding, zero emission energy innitiative could be materialized under multiple heterojunctions in photocatalytic process is beneficial for enhancing the H2 production. © 2025 The Authors

关键词： Titanium dioxide

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Phase coherence and electron-electron interactions in epitaxial strained SrTiO3 films on Si(001)

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Physical Review B 2025年第15期111卷 155307-155307页

作者： Ryan J. Cottier Barry D. Koehne John T. Miracle Daniel A. Currie Craig H. Swartz Nikoleta Theodoropoulou Department of Physics Texas State University San Marcos Texas 78666 USA Materials Science Engineering and Commercialization Program Texas State University San Marcos Texas 78666 USA

Oxide heterostructures based on SrTiO3 have emerged as a rich platform for exploring physical phenomena, most notably conductivity at interfaces between insulators. In this study, we investigate the electronic properties of an oxide-semiconductor heterostructure—SrTiO3 films grown epitaxially on Si(001). The lattice mismatch induces epitaxial strain, breaking the cubic symmetry of SrTiO3 and resulting in tetragonal distortion. Magnetotransport measurements reveal that the temperature and magnetic field dependence of the conductivity are dominated by two-dimensional quantum effects, weak localization, and electron-electron interactions. The low-temperature electronic properties indicate quantum confinement, strong electron correlations, exchange interactions, and Zeeman spin splitting. These findings underscore the potential of the SrTiO3/Si heterostructure for designing oxide-based quantum devices.

关键词： Lattice mismatch

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Mo-terminated edges in two-dimensional molybdenum disulfide for site-specific hydrolysis and DNA cleavage

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materials Today 2025年 86卷 162-171页

作者： Wang, Cong Wu, Menghan Li, Muqing Zhao, Yingcan Zhao, Mingchuang Zhang, Yunhao Bai, Yichao Gao, Jianxiang Wang, Xiaoxia Tian, Xilin Zhang, Han Chang, Liang Zou, Xiaolong Liu, Bilu Kang, Feiyu Terrones, Mauricio Lei, Yu Institute of Materials Research Shenzhen Key Laboratory of Advanced Layered Materials for Value-added Applications Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials & Center of Double Helix Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Institute of Materials Research & Shenzhen Geim Graphene Center Shenzhen Key Laboratory of Advanced Layered Materials for Value-added Applications Tsinghua-Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Environmental Science Program Department of Life Sciences Beijing Normal University-Hong Kong Baptist University United International College Guangdong519087 China Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Department of Physics Department of Chemistry Department of Materials Sciences Center for 2-Dimensional and Layered Materials The Pennsylvania State University University ParkPA16802 United States International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale Optoelectronics Shenzhen University Shenzhen518060 China

The hydrolysis of DNA serves as the foundational principle for gene engineering that enable precise gene cleavage at the molecular level. This process typically occurs in biological nucleases, which exhibit nucleobase-selective and catalytic hydrolysis capabilities rarely replicated in abiotic nanomaterials. Here, we demonstrate that molybdenum-terminated (Mo-terminated) edges of molybdenum disulfide (MoS2) possess the unique ability to abstract a proton (H+) from water molecules, thereby facilitating catalytic hydrolysis reactions that cleave the phosphodiester bonds in DNA through the action of hydroxide ions. The enhanced proton absorption at Mo-terminated edges of MoS2 significantly reduces the activation energy required for the DNA hydrolysis reaction. Furthermore, the favorable interaction between the Mo-terminated edges and thymine nucleobases promotes both charge transfer and P-O bond cleavage, enabling targeted DNA hydrolysis at 'TTTTTTT' sequences under dark conditions. This discovery underscores the potential of MoS2 as a stable, efficient nanosystem for precise genetic editing, heralding advanced applications in the field of gene engineering. © 2025 The Author(s)

关键词： Activation energy

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Improving energy conversion efficiency of ion-driven artificial muscles based on carbon nanotube yarn

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Journal of Power Sources 2025年 646卷

作者： Hyeon, Jae Sang Wang, Qiong Tawfick, Sameh Lee, JeongA Smith, Kyle C. Zhang, Mengmeng Park, Jong Woo Song, Gyu Hyeon Wang, Zhong Fang, Shaoli Baughman, Ray H. Kim, Seon Jeong Department of Biomedical Engineering and Electronic Engineering Hanyang University Seoul04763 Korea Republic of Department of Mechanical Science and Engineering Grainger College of Engineering University of Illinois at Urbana-Champaign Urbana61801 United States Department of Materials Science and Engineering Grainger College of Engineering University of Illinois at Urbana-Champaign Urbana61801 United States Beckman Institute for Advanced Science and Technology Grainger College of Engineering University of Illinois at Urbana-Champaign Urbana61801 United States Computational Science and Engineering Program Grainger College of Engineering University of Illinois at Urbana-Champaign Urbana61801 United States Alan G. MacDiarmid NanoTech Institute University of Texas at Dallas Richardson75080 United States

While artificial muscles provide giant work and power densities compared to natural muscles, their reported energy conversion efficiencies have so far been low. We here demonstrate a tension optimization process (TOP) for fabricating coiled carbon nanotube artificial muscles having record efficiencies. These TOP muscles were made by applying about 20 times higher tensile stress during pre-coiling twist insertion than the tensile stress applied during coiling, resulting in high twist density and high spring index. The TOP muscles driven by the tetrabutylammonium cation provide 6.1 J/g contractile work, which is ∼152 times the maximum capability of human skeletal muscles, and 13.1 % contractile energy efficiency. In addition, the contractile energy efficiency of the TOP muscles driven by the bis(trifluoromethanesulfonyl)imide anion is maximized to 38.8 % by minimizing side redox reactions. In the case of full-cycle actuation, which considers the whole cycle of contraction and relaxation, we increased the full-cycle energy conversion efficiency of TOP muscles to 6.7 %, which is 4.5 times that previously reported for ion-driven artificial muscles. © 2025 Elsevier B.V.

关键词： Energy conversion efficiency

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Assessing the Microstructure of SnBiZn Alloys during Semisolid Treatment

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Advanced engineering materials 2025年

作者： de Siqueira Simioli, Carolina de Gouveia, Guilherme Lisboa Spinelli, José Eduardo Department of Materials Science and Engineering Federal University of São Carlos Rod. Washington Luis SP São CarlosCEP 13565–905 Brazil Graduate Program in Materials Science and Engineering Federal University of São Carlos Rod. Washington Luis Km 235 SP São CarlosCEP 13565-905 Brazil

The development of new alloys for semisolid processing is a key demand of Industry 4.0, driven by the limited knowledge in this area, particularly for Sn-based alloys. The primary goal is to design alloys suitable for thixocasting and semisolid additive manufacturing. While Zn is known to influence SnBi alloys by affecting their microstructure, wettability, and intermetallic compound formation, its impact on globule size, morphology, and microstructural coarsening/stability over aging remains largely unexplored, despite the potential implications for semisolid processability and final product reliability. In this research, stability in high-temperature experiments is verified for the Sn40Bi and Sn40Bi2Zn alloys (wt%). Five different heat treatment periods of 20, 40, 60, 90, and 120 min are applied to the samples, each subjected to its respective eutectic temperature according to CALPHAD computations. The microstructure of both alloys is characterized by Sn-rich globules for times higher than 90 min, which are noticeably finer and less elongated in the Sn40Bi2Zn alloy compared to the Sn40Bi. This globule refinement in Sn40Bi2Zn alloy can be attributed to the presence of Zn needles at the dendrite boundaries that pin the Sn-rich regions and prevent them from growing freely. Over time, while Bi saturates near its solubility limit in Sn matrix at 60 min and remains stable up to 120 min, the Sn40Bi2Zn alloy exhibits a progressive increase in Bi content between 60 and 120 min, reaching the saturation level at 120 min. The Sn40Bi2Zn alloy exhibits higher globule microhardness in the 90 min samples, primarily due to Zn hardening in solid solution. © 2025 The Author(s). Advanced engineering materials published by Wiley-VCH GmbH.

关键词： Niobium alloys

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