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Effect of Cu content on microstructural evolution and mechanical behavior of Al–Cu–Mg–Ag alloys

Journal of materials Research and Technology 2025年 36卷 5222-5236页

作者： Lianzhou Li Wentao Liu Namin Xiao Xingwu Li Haoyan Meng Jingjing Ruan Liang Jiang Lilong Zhu Institute for Advanced Studies in Precision Materials Yantai University Yantai Shandong 264005 China School of Materials Science and Engineering Shandong University of Science and Technology Qingdao Shandong 266590 China AECC Beijing Institute of Aeronautical Materials Beijing 100095 China

This study systematically investigates the effect of Cu content (2.77–6.80 wt%) on the microstructural evolution and mechanical behavior of Al–Cu–Mg–Ag alloys through comprehensive characterization using scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The relationship between microstructure and yield strength (YS) was quantitatively analyzed using multiple strengthening models. Experimental results demonstrate that increasing Cu content promotes eutectic phase formation (θ-Al 2 Cu, T-Al 20 Cu 2 Mn 3 and Ag-containing S-Al 2 CuMg) in as-cast microstructures, accompanied by a transition from dendritic to cellular dendritic grain morphology. Coarse surplus phases (CSPPs) facilitate particle-stimulated nucleation (PSN), enhancing recrystallization to a maximum of 88.91 % at 6.80 wt% Cu. The number density of the Ω phase exhibits a non-monotonic dependence on Cu content, reaching a maximum of 6.72E+22 m −2 at 4.68 wt% Cu, while θ′ phase precipitation is significantly suppressed. Mechanical properties and grain boundary characteristics show strong Cu content dependence: increasing Cu content reduces precipitate-free zone (PFZ) width and transforms grain boundary precipitates (GBPs) from discontinuous to continuous distributions. Yield strength demonstrates a positive correlation with Cu content, while ductility follows an inverse trend. Strengthening mechanism analysis reveals that Ω phase precipitation dominates the yield strength enhancement.

关键词： Al–Cu–Mg–Ag alloys Microstructural evolution Precipitation Mechanical properties Strengthening mechanism

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Solid structure of Li2BeF4 (FLiBe) from room temperature to melting studied by neutron and X-ray diffraction

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Journal of Applied Crystallography 2025年 58卷 435-446页

作者： Gardner, D. Nathanael Williams, Haley Vogel, Sven C. Fayfar, Sean Khaykovich, Boris Srivastava, Shivani Hwang, Andrea Asta, Mark Sprouster, David Olds, Dan Vershbow, Gregory Neuefeind, Jörg C. Scarlat, Raluca O. Department of Nuclear Engineering University of California Berkeley BerkeleyCA94720 United States Los Alamos National Laboratory Los AlamosNM87545 United States Nuclear Reactor Laboratory Massachusetts Institute of Technology CambridgeMA02139 United States Department of Materials Science and Engineering University of California Berkeley BerkeleyCA94720 United States Department of Materials Science and Chemical Engineering Stony Brook University Stony BrookNY11784 United States National Synchrotron Light Source II Brookhaven National Laboratory UptonNY11973 United States Department of Visual Studies University of Pennsylvania PhiladelphiaPA19104 United States Neutron Sciences Directorate Oak Ridge National Laboratory Oak RidgeTN37831-6475 United States

Molten fluoride salts such as Li2BeF4 (FLiBe) are used in molten salt reactors fluoride-salt-cooled high-temperature reactors and fusion reactors as a fuel solvent, coolant and/or tritium breeding medium. In engineered systems that use molten salt, solid-state material will be present during melting and freezing scenarios, and therefore the temperature-dependent properties of the solid and solid/liquid phase transition merit investigation. To observe the behavior of the solid state of Li2BeF4 from room temperature to melting, this work used neutron and X-ray diffraction to measure the changes in the lattice parameters and volume of the crystalline unit cell and compared the results with prior low-temperature data for solid Li2BeF4. From neutron diffraction data it is also possible to identify anisotropy: centimetre-scaled crystals align preferentially with the a axes parallel to the direction of freezing front propagation, and the c axes expand 54% more than the a axes. This work provides the lattice constants as a function of temperature, quantifies the thermal expansion, and determines the equation describing the change in density for solid Li2BeF4 from room temperature to 459°C to be ρsolid (kg m-3) = 2182 (3) - 0.115 (2) T (°C) and the volume expansion upon melting to be less than 5%. This density changes depending on molecular weight and enrichment. © 2025 International Union of Crystallography. All rights reserved.

关键词： Lattice constants

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Basal and Edge Plane Activity of Two-Dimensional Dirac Semimetal Nite2 for Hydrogen Evolution Reaction

SSRN

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SSRN 2025年

作者： Cho, Suyeon Jeong, Seung Weon Kim, Jeong Hyo Lee, Seungyeon Yang, Heejun Lee, Sangheon Division of Chemical Engineering and Materials Science Graduate Program in System Health Science and Engineering Ewha Womans University Seoul03760 Korea Republic of Daejeon34141 Korea Republic of

. Nickel ditelluride (NiTe2), one of group-10 transition metal dichalcogenides, has shown intriguing surface states originating from its topological semi-metallicity. Here, we demonstrate abnormal catalytic activities at the NiTe2 surface for hydrogen evolution reaction (HER). We investigate the differences in catalytic activities at the basal and edge planes of NiTe2 using a micro-sized electrochemical reactor. The basal plane is found to be more active than the edge plane, resulting in a current density at the basal plane of NiTe2 exceeding 800 mA/cm2 with a small overpotential of -0.162 V. We conduct ab initio calculations to estimate the intrinsic catalytic activities of HER on the basal and edge planes of NiTe2. Interestingly, our calculation results suggest that the active sites at the edge plane are electrochemically more active than those at the basal plane. The discrepancy between the experimental measurements and theoretical predictions for the crystal-orientation-dependent HER activity highlights that the specialty of a topological semimetal plays a vital role in determining the HER rate for NiTe2 nanoparticle catalysts © 2025, The Authors. All rights reserved.

关键词： Hydrogen evolution reaction

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Highly Elliptic Circular Dichroism of Copper Aspartate One-Dimensional Nanostructures across the Ultraviolet to Terahertz Ranges

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Nano Letters 2025年第19期25卷 7699-7706页

作者： Choi, Won Jin Kim, Ji-Young Hwang, Myonghoo Lim, Chung Man Park, Bum Chul Emre, Ahmet Lee, Sang Hyun Kotov, Nicholas A. Department of Chemical Engineering University of Michigan Ann ArborMI48109 United States Biointerfaces Institute University of Michigan Ann ArborMI48109 United States Physical Life and Sciences Lawrence Livermore National Laboratory LivermoreCA94550 United States Department of Chemical and Biological Engineering Rensselaer Polytechnic Institute TroyNY12180 United States Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute TroyNY12180 United States Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States University of Michigan Ann ArborMI48109 United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States

Since the discovery of chirality, circular dichroism (CD) of mirror-asymmetric molecules has been studied across the ultraviolet, visible, and near-infrared ranges. Recently, chiroptical activity studies have expanded to the terahertz (THz) range, where resonance peaks originate from collective vibrations of tens and hundreds of atoms. In this study, we synthesized Cu2+ coordination complexes with L- and D-aspartic acid as nanowires and nanorods and characterized their chiroptical activity across multiple frequency ranges. Both chiral nanostructures exhibit strong electronic CD (ECD), primarily from Cu2+ d-d transitions, while vibrational CD (VCD) spectra show sharp C=O, C-H, and O-H vibronic peaks, indicating higher atomic defect densities in nanorods than nanowires. Although THz CD (TCD) spectra are broad, they exhibit ∼1000× greater ellipticity than ECD and VCD, perhaps warranting previous references to circular dichroism of nanostructures as giant. Comparative TCD analysis highlights strong chiral phonon sensitivity, underscoring its potential for probing defect densities and structural changes for various chiral nanostructures and (bio)crystals. © 2025 American Chemical Society.

关键词： Terahertz spectroscopy

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Fluorescent Sodium Alginate Hydrogel-Carbon Dots Sensor for Detecting Perfluorooctanoic Acid in Potable Water

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Analytical Chemistry 2025年第18期97卷 10075-10084页

作者： Mohammadi, Somayeh Sandoval-Pauker, Christian Dorado, Zayra N. Senftle, Thomas P. Pankow, Robert Sharifan, Hamidreza Department of Chemistry and Biochemistry University of Texas at El Paso El PasoTX79968 United States Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Metallurgical & Materials Engineering The University of Texas at El Paso 500 West University Avenue El PasoTX79902 United States Department of Chemical and Biomolecular Engineering Rice University HoustonTX77005 United States Environmental Science and Engineering Program University of Texas at El Paso El PasoTX79968 United States

Per- and polyfluoroalkyl substances (PFASs), especially perfluorooctanoic acid (PFOA), are emerging environmental and health concerns due to their persistence, resistance to degradation, and bioaccumulation. In this study, we developed a sensitive and selective detection platform based on a sodium alginate (SA) hydrogel modified with nitrogen and fluorinated carbon dots (N,F-CDs) to enhance the detection of PFOA in natural and engineered water systems. The SA hydrogel-N,F-CD composite exhibited strong fluorescence at 480 nm after optimization, achieving a detection limit as low as 0.001 ppt. The sensor was characterized by using Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FT-IR), Powder X-ray Diffraction (PXRD), X-ray Photoelectron Spectroscopy (XPS), and zeta potential spectroscopy, revealing its structural integrity, functional groups, and the surface charge of the SA hydrogel-N,F-CDs network. Sensitivity assessments demonstrated a linear fluorescence response to PFOA concentrations ranging from 1 to 66 ppq. Selectivity tests confirmed the sensor’s ability to distinguish PFOA from other perfluorinated compounds, with minimal interference from other substances. The practical applicability of the sensor was validated using spiked recovery experiments with tap water samples from various locations, achieving recovery rates between 94% and 106.6%. This sensor offers a reliable, efficient, and highly sensitive platform for the detection of PFAS, demonstrating its potential for real-world PFAS-monitoring applications. © 2025 American Chemical Society.

关键词： Fourier transform infrared spectroscopy

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Porous Poly(vinylidene fluoride-co-hexafluoropropylene)/copper oxide nanocomposite membranes for piezoelectric strain sensing

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Discover Applied sciences 2025年第5期7卷 1-17页

作者： Al-Ejji, Maryam Promi, Tamanna Sangor, Farah Al-Awa, Zinab Bonthula, Sumalatha Radhika, V. Ponnamma, Deepalekshmi Center for Advanced Materials Qatar University P O Box 2713 Doha Qatar Department of Biological and Environmental Sciences Qatar University P O Box 2713 Doha Qatar Department of Chemical Engineering University of Calicut Kerala Thenhipallam India Materials Science and Technology Program Department of Mathematics Statistics and Physics College of Arts and Sciences Qatar University Doha2713 Qatar

The emerging field of porous piezoelectric strain sensors attracted a wide range of applications in healthcare monitoring, wearable electronics, and other dynamic applications due to their durability, high sensitivity, and real-time monitoring. This study presents the development of porous poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/copper oxide (CuO) nanocomposite membranes for piezoelectric strain sensing. The morphology and the dispersion of CuO nanoparticles and nanofibers in PVDF piezoelectric films with different nano-CuO contents are studied by X-ray diffraction, Fourier transform infrared spectrum, scanning electron microscopy and dielectric studies. The PVDF-HFP acts as a scaffold, allowing ions to flow within the porous percolated channels, resulting in a highly robust membrane with desired dielectric properties. The DMA studies enhanced the strain sensing performance of the 3.5 and 7 wt.% CuO nanofibers loaded with PVDF-HFP membranes compared with the 3.5 and 7 wt.% CuO nanoparticles and pristine membranes. The dielectric properties of the composites also showed high storage values for the CuO/PVDF-HFP samples compared to the pristine polymer. Moreover, the surface water contact angles of the membranes have slightly increased after loading the nanomaterial into the PVDF-HFP matrix, which strongly influenced the surface energies, indicating hydrophobicity. The current study, thus, demonstrates the piezoelectric strain sensing devices made from PVDF-HFP/CuO nanofibers for humid atmospheres. © The Author(s) 2025.

关键词： Fourier transform infrared spectroscopy

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Comparative Study of Testing Indigenous Air Filters for Fine PM Removal 1st

Comparative Study of Testing Indigenous Air Filters for Fine...

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1st International Conference on Pollution Control for Clean Environment, ICPCCE 2023

作者： Nawale, Prashant Sahu, Manoranjan Aerosol and Nanoparticle Technology Laboratory Environmental Science and Engineering Department Indian Institute of Technology Bombay Mumbai400076 India Interdisciplinary Program in Climate Studies Indian Institute of Technology Bombay Mumbai400076 India Centre for Machine Intelligence and Data Science Indian Institute of Technology Bombay Mumbai400076 India

ISBN: (纸本)9789819778454

Air pollution has become a serious global issue, which has significant impacts on both human health and the environment. Over the past decade, air quality has deteriorated due to various anthropogenic activities including construction, urbanization and industrialization. These activities release hazardous particles and harmful gases into the atmosphere, contributing to poor air quality. Developing countries such as India have been particularly affected, with some of their cities among the most polluted worldwide. To address this serious concern, it is imperative to develop and implement air pollution control technologies for both indoor and outdoor environments. This study focuses on the structured investigation of the performance of locally available air filter media in terms of their removal efficiency for submicron and micron-size particles. Various indigenous air filter media are subjected to rigorous testing to evaluate their overall and size-specific filtration efficiency and corresponding differential pressure drop. The results of these performance evaluations are then compared to their effectiveness in removing coarse and fine particles from the air. This research aims to provide valuable insights into the development of effective air filtration systems to combat air pollution. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Air filters Air pollution control technology Air purification Coarse PM Fine PM

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Osteogenic Potential of 3D-Printed Porous Poly(lactide-co-trimethylene carbonate) Scaffolds Coated with Mg-Doped Hydroxyapatite

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ACS Applied materials and Interfaces 2025年第21期17卷 31411-31433页

作者： Aydin, Mehmet Serhat Nicolae, Carmen-Valentina Campodoni, Elisabetta Mohamed-Ahmed, Samih Kadousaraei, Masoumeh Jahani Yassin, Mohammed Ahmed Gjerde, Cecilie Sandri, Monica Stancu, Izabela-Cristina Rashad, Ahmad Mustafa, Kamal Center of Translational Oral Research (TOR) Department of Clinical Dentistry University of Bergen Bergen 5009 Norway Advanced Polymer Materials Group Faculty of Chemical Engineering and Biotechnologies National University of Science and Technology Politehnica Bucharest Bucharest 011061 Romania Institute of Science Technology and Sustainability for Ceramics (ISSMC-CNR) Ravenna Faenza 48018 Italy Faculty of Medical Engineering National University of Science and Technology Politehnica Bucharest Bucharest 011061 Romania Bioengineering Graduate Program University of Notre Dame Notre Dame 46556 IN United States

Extrusion-based 3D printing of thermoplastic polymers presents significant potential for bone tissue engineering. However, a key limitation is the frequent absence of filament porosity and the inherent osteoconductive properties. This study addresses these challenges by fabricating poly(lactide-co-trimethylene carbonate) (PLATMC) scaffolds with dual-scale porosity: macroporosity achieved through controlled filament spacing and microporosity introduced via NaCl leaching. The inclusion of NaCl generated rough, porous surfaces that were well-suited for dip-coating with magnesium-carbonate-doped hydroxyapatite (MgCHA), thereby imparting osteoconductive functionality. Thermal analysis revealed that salt incorporation had minimal impact on the polymer’s thermal stability. Rheological studies and computational modeling indicated that NaCl reduced the viscosity under shear, leading to enhanced printability and faster extrusion speeds. After leaching, the scaffolds exhibited approximately 34% microporosity, which significantly increased water uptake and swelling capacity, despite the roughened surfaces slightly elevating hydrophobicity. The mechanical properties of PLATMC (with nonporous filaments) and p-PLATMC (with porous filaments) scaffolds showed a modulus of elasticity of 566 ± 118 and 101 ± 20 MPa, respectively, with strain values of 178 ± 54% and 84 ± 28%. Biological evaluations highlighted the compatibility of the p-PLATMC scaffolds. Cell viability and proliferation assays confirmed sustained cellular interaction over a 14 day period. Notably, alkaline phosphatase (ALP) activity was elevated in the porous scaffolds, and the MgCHA coating significantly enhanced mineral deposition by day 28, suggesting improved osteogenic potential. In conclusion, this study presents a robust strategy for fabricating 3D-printed PLATMC scaffolds with integrated filament porosity, offering a viable platform for osteoconductive coatings in bone tissue engineering applications. © 2025 The

关键词： bone tissue engineering magnesium doped-hydroxyapatite microporosity polymeric scaffolds surface modification

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Contractive Difference-of-Convex Algorithms

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Journal of Optimization Theory and Applications 2025年第1期206卷 1-21页

作者： He, Songnian Dong, Qiao-Li Rassias, Michael Th. Tianjin Key Laboratory for Advanced Signal Processing and College of Science Civil Aviation University of China Tianjin300300 China Department of Mathematics and Engineering Sciences Hellenic Military Academy Vari Attikis16673 Greece Institute for Advanced Study Program in Interdisciplinary Studies 1 Einstein Dr Princeton08540 United States

The difference-of-convex algorithm (DCA) and its variants are the most popular methods to solve the difference-of-convex optimization problem. Each iteration of them is reduced to a convex optimization problem, which generally needs to be solved by iterative methods such as proximal gradient algorithm. However, these algorithms essentially belong to some iterative methods of fixed point problems of averaged mappings, and their convergence speed is generally slow. Furthermore, there is seldom research on the termination rule of these iterative algorithms solving the subproblem of DCA. To overcome these defects, we firstly show that the subproblem of the linearized proximal method (LPM) in each iteration is equal to the fixed point problem of a contraction. Secondly, by using Picard iteration to approximately solve the subproblem of LPM in each iteration, we propose a contractive difference-of-convex algorithm (cDCA) where an adaptive termination rule is presented. Both global subsequential convergence and global convergence of the whole sequence of cDCA are established. Finally, preliminary results from numerical experiments are promising. © The Author(s), under exclusive licence to Springer science+Business Media, LLC, part of Springer Nature 2025.

关键词： Conjugate gradient method

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Energy Gain Kernel for Climate Feedbacks. Part III: Reconciliation of the Apparent "Negative" Nature of Lapse-Rate Feedback

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Journal of the Atmospheric sciences 2025年第5期82卷 917-931页

作者： Sun, Jie Cai, Ming Hu, Xiaoming Feng, Jing Ding, Feng Department of Earth Ocean and Atmospheric Science Florida State University TallahasseeFL United States School of Atmospheric Sciences Sun Yat-sen University Southern Marine Science and Engineering Guangdong Laboratory Zhuhai China Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Zhuhai China Atmospheric and Oceanic Sciences Program Princeton University PrincetonNJ United States Department of Atmospheric and Oceanic Sciences Peking University Beijing China

In Part I of this three-part series, we derive the energy gain kernel (EGK) to represent energy amplification by temperature feedback. We here demonstrate that due to the amplification, the vertically integrated total energy perturbations from input energy at a single layer can be 2–15 times greater than the input energy. The lower the level where input energy is placed, the greater the total energy perturbations are. Temperature feedback alone amplifies the vertically integrated global mean anthropogenic radiative forcing nearly 14 times, compared to 5.2 times by nontemperature feedbacks. Such great amplification arises from the continuous back-and-forth relay of warming-induced thermal emissions from individual layers to absorption by other layers throughout the atmosphere–surface column until the system reaches a new equilibrium state. Outgoing longwave radiation reflects the vertically integrated net cooling rate and cannot capture the absorption/emission at individual layers. The lapse-rate feedback mainly reflects the level where input energy is placed, rather than the physical nature of air temperature feedback. Its sign changes from positive for input energy at lower levels to negative for input energy at upper levels. Because energy perturbations due to radiative processes tend to have vertically decreasing profiles, their lapse-rate feedback tends to be predominantly positive. When also considering nonradiative feedbacks, such as enhanced vertical convection, the net effect of nontemperature feedbacks tends to be weak or even negative at the surface but strongly positive in the upper atmosphere in the tropics. This explains why the lapse-rate feedback is predominantly negative in the tropics. © 2025 American Meteorological Society.

关键词： Global warming

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