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arXiv 2024年

作者： Li, Yanfei Liu, Juejing Zhao, Xiaodong Liu, Wenjun Geng, Tong Li, Ang Zhang, Xin Pacific Northwest National Laboratory RichlandWA99354 United States Materials Science and Engineering Program Washington State University PullmanWA99164 United States Advanced Photon Source Argonne National Laboratory LemontIL60439 United States Department of Electrical and Computer Engineering University of Rochester New York14627 United States

Traditional analysis of highly distorted micro-X-ray diffraction (μ-XRD) patterns from hydrothermal fluid environments is a time-consuming process, often requiring substantial data preprocessing and labeled experimental data. This study demonstrates the potential of deep learning with a multitask learning (MTL) architecture to overcome these limitations. We trained MTL models to identify phase information in μ-XRD patterns, minimizing the need for labeled experimental data and masking preprocessing steps. Notably, MTL models showed superior accuracy compared to binary classification CNNs. Additionally, introducing a tailored cross-entropy loss function improved MTL model performance. Most significantly, MTL models tuned to analyze raw and unmasked XRD patterns achieved close performance to models analyzing preprocessed data, with minimal accuracy differences. This work indicates that advanced deep learning architectures like MTL can automate arduous data handling tasks, streamline the analysis of distorted XRD patterns, and reduce the reliance on labor-intensive experimental datasets. Copyright © 2024, The Authors. All rights reserved.

关键词： Deep learning

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Statistical Analysis of Polyester Resin Composite Reinforced with Miriti Fibers Braided Using Crochet Technique

SSRN

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SSRN 2023年

作者： Freires, Altairley M. de Corrêa, Alessandro C. Ribeiro, Mauricio M. Cardoso, Silmara M. da Rodrigues, Jean S. Silva, Douglas Santos Junio, Raí Felipe Pereira Monteiro, Sergio Neves Federal Institute of Education Science and Technology of Pará – IFPA Materials Engineering Program Avenida Almirante Barroso 1155 Marco PA BelémCEP 66093-020 Brazil Federal Institute of Education Science and Technology of Pará - IFPA Estrada do Icuí Guajará PA AnanindeuaCEP 67125-000 Brazil Military Institute of Engineering – IME Department of Materials Science Praça General Tibúrcio 80 Praia Vermelha Urca RJ Rio de JaneiroCEP 22290-270 Brazil

This work presents an experimental investigation of the mechanical properties of composites reinforced with crocheted fabrics of miriti fibers (Mauritia flexuosa) in a polyester matrix. The fabrics were manufactured under different grammages, with and without alkaline fiber treatment. The composites were produced using two different viscosity conditions of the polyester matrix and part of these underwent post-cure treatment at 60°C. In order to evaluate the effects of the input variables, the samples were produced by manual lamination with curing under vacuum, following a complete factorial experimental matrix type 24, tested according to the ASTM D 3039 standard. The results showed that the variables alkaline treatment of the fibers and viscosity of the matrix presented statistically significant effects on the responses limit of tensile strength and modulus of elasticity. The highest level of tensile strength (13.02 MPa) was obtained in composites with alkaline treatment of the fibers, fabric grammage 473.9 g/cm2, matrix with higher viscosity and post-cure application, while the modulus of elasticity obtained the best performance (1.59 GPa) in samples without alkaline treatment of the fibers, manufactured with the fabric of lower grammage, with a more viscous matrix and that underwent post-curing. © 2023, The Authors. All rights reserved.

关键词： Fibers

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Coupling between bulk thermal defects and surface segregation dynamics

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Physical Review B 2021年第8期104卷 085408-085408页

作者： Jonathan Li Siming Zhang Chaoran Li Yaguang Zhu Jorge Anibal Boscoboinik Xiao Tong Jerzy T. Sadowski Guofeng Wang Guangwen Zhou Department of Mechanical Engineering & Materials Science and Engineering Program State University of New York Binghamton New York 13902 USA Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh Pennsylvania 15261 USA Center for Functional Nanomaterials Brookhaven National Laboratory Upton New York 11973 USA

Surface segregation is a phenomenon that depends on the delicate interplay between thermodynamic driving forces and kinetic obstacles, for which elevated temperature is often needed to enhance the atom mobility and reach equilibrium. Using the classic system of Cu3Au(100) under nonisothermal conditions, herein, we show an adatom process underlying transient surface segregation dynamics through the temperature-change-driven creation and annihilation of thermal vacancies in the bulk and the resulting bulk-surface mass exchanges. This is demonstrated by monitoring the surface composition evolution of Cu3Au(100) with temperature changes between 250 and 500∘C, showing that the increase in temperature decreases monotonically the surface Au concentration as a result of the transfer of more Cu than Au from the bulk to the surface to form Cu-rich clusters of adatoms. Such a bulk thermal defect effect is expected to be universal in inducing the disparity in the bulk-surface mass exchanges of dissimilar atoms in multicomponent materials because of the inherent differences in the vacancy formation energies of the constituent atoms.

关键词： Self-diffusion Surface & interfacial phenomena Transition metal alloys Density functional calculations Ion beam analysis Mass spectrometry Scanning tunneling microscopy X-ray photoelectron spectroscopy

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Potential of caffeic acid as an effective natural antioxidant for polypropylene-polyethylene copolymers: A DFT and experimental study

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Current Research in Green and Sustainable Chemistry 2024年 9卷

作者： Hernández Fernández, Joaquín Alejandro Ortiz Paternina, Katherine Liset López Martínez, Juan Chemistry Program Department of Natural and Exact Sciences University of Cartagena Chemical Engineering Program School of Engineering Universidad Tecnológica de Bolivar Parque Industrial y Tecnológico Carlos Velez Pombo Department of Natural and Exact Science Universidad de la Costa Polytechnical University of Valencia (UPV) Institute of Materials Technology (ITM)

Caffeic acid (CAF) i is a polyphenolic compound commonly found in plants, valued for its ability to act as an antioxidant. This study focused on investigating the impact of a natural antioxidant, specifically caffeic acid (CAF), compared to two synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), on the thermal stability of propylene/ethylene copolymer (C-PP/PE), Aiming to establish a theoretical framework for the advancement of novel polymeric antioxidant compounds. Theoretical calculations were conducted to determine each compound's thermodynamic properties and antioxidant activity. The phenolic hydroxyl bond dissociation enthalpy (BDE) values revealed that BHA had the lowest value (325.6 kJ mol⁻¹), trailed by CAF (328.2 kJ mol⁻¹) and BHT (341.3 kJ mol⁻¹), indicating a higher electron-donating capacity of BHA. Transition energy (TS) calculations indicated that BHA had the lowest TS energy (49.29 kJ mol⁻¹), succeeded by CAF (57.61 kJ mol⁻¹) and then BHT (75.57 kJ mol⁻¹), suggesting greater efficiency in radical scavenging. Additionally, the obtained rate constants showed that CAF had the highest hydrogen abstraction rate (k = 1.05 × 10⁵ M⁻¹ s⁻¹), followed by BHA (k = 1.17 × 10⁴ M⁻¹ s⁻¹), and then BHT (k = 4.2 × 10³ M⁻¹ s⁻¹). These results support the effectiveness of CAF as a potentially more active antioxidant. In the experimental part of this study, it was observed that C-PP/PE with BHA showed a lower melt flow index (MFI) (8.51), indicating more excellent thermal stability. On the other hand, samples containing natural caffeic acid extracts exhibited a gradual decrease in MFI with increasing CAF concentration (MFI of 9.4, 8.82, 7.59, 6.44, and 5.98 for concentrations of 0.025, 0.05, 0.075, 0.1, and 0.125 ppm, respectively), suggesting a progressive improvement in the thermal stability of C-PP/PE

关键词： Activation energy Antioxidant Bond dissociation energy Caffeic acid MFI Stability

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Effect of Polyisoprene Microstructure on the Thermodynamics, Viscoelastic, and Dielectric Properties in the Bulk and during Flow in Nanopores

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Macromolecules 2025年第12期58卷 6052-6065页

作者： Panagiotis Kardasis Michail Danikas Nikolaos Patelis Konstantinos Ntetsikas Nikos Hadjichristidis George Floudas Department of Physics University of Ioannina 45110 Ioannina Greece Polymer Synthesis Laboratory Chemistry Program KAUST Catalysis Center Physical Sciences and Engineering Division King Abdullah University of Science and Technology (KAUST) Thuwal 23955 Saudi Arabia Department of Physics University of Ioannina 45110 Ioannina Greece；Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany；University Research Center of Ioannina (URCI)─Institute of Materials Science and Computing 45110 Ioannina Greece

We report the effect of polyisoprene (PI) microstructure on the thermodynamics, viscoelasticity, and molecular dynamics, the latter via dielectric spectroscopy in bulk and during flow in cylindrical nanopores. A series of monodisperse PIs with microstructurescis-1,4,trans-1,4, 3,4, and 1,2 are synthesized via anionic polymerization using high-vacuum techniques using polar additives. In thermodynamics, we show that the liquid-to-glass temperature (Tg) decreases linearly with 1,4 units content asTg[K] = (289 ± 4)–0.9 ×w1,4%, whereas it increases quadratically with 3,4-units content asTg=Tg0%+(w3,4%)250[K]. Scaling of specific heats,cpglass,cpliquid,Tg, and the increment in specific heat atTg(Δcp) are established as a function of microstructure. In rheology, the zero-shear viscosity scales as η0= η0%×w1,4%–u, whereu= 5.4 ± 0.3. Despite this, the plateau modulus is independent of microstructure. All dielectrically active processes are strongly affected by microstructure. The dielectric strength of the β- and α-processes increases strongly with increasing 3,4-unit content, whereas that of the chain mode decreases precipitously. The calculated component of dipole moment along the polymer backbone scales with microstructure as μcis–1,4> μtrans–1,4> μ1,2> μ3,4≈ 0. The β-process shifts withTgand has characteristics of a Johari–Goldstein process with activation energies predicted by the coupling model. Lastly, we show that it is possible to separate blend components comprising different microstructures by the way of penetration within cylindrical nanopores, giving another example of what is known as “topology sorting.”

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Elastocaloric effect in amorphous polymer networks undergoing mechanotropic phase transitions

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Physical Review materials 2021年第6期5卷 L062401-L062401页

作者： J. A. Koch J. A. Herman T. J. White Department of Chemical and Biological Engineering University of Colorado Boulder Boulder Colorado 80309 USA Materials Science and Engineering Program University of Colorado Boulder Boulder Colorado 80309 USA

Deformations of amorphous polymer networks prepared with significant concentrations of liquid crystalline mesogens have been recently reported to undergo mechanotropic phase transitions. Here, we report that mechanotropic phase transitions are accompanied by an elastocaloric response (ΔT=2.9 K). Applied uniaxial strain to the elastomeric polymer network transitions the organization of the material from a disordered, amorphous state (order parameter Q=0) to the nematic phase (Q=0.47). Both the magnitude of the elastocaloric temperature change and the mechanically induced order parameter are dependent on the concentration of liquid crystal mesogens in the material.

关键词： Elastic deformation Liquid crystal phase transitions Elastomers Liquid crystals

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The effects of selectively blocking the electron transport layer of n-i-p perovskite solar cells with polymer particles on device performance

RSC Applied Interfaces

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RSC Applied Interfaces 2024年第3期1卷 591-599页

作者： Altujjar, Amal Wang, Ran Wang, Xuelian Saunders, Jennifer M. Jia, Zhenyu Spencer, Ben Hodson, Nigel Jacobs, Janet Alkhudhari, Osama M. Thomas, Andrew Curry, Richard Saunders, Brian R. Department of Materials University of Manchester MECD Building A Manchester M1 7HL United Kingdom Basic Science Department Deanship of Preparatory Year and Supporting Studies Imam Abdulrahman Bin Faisal University Dammam 34221 Saudi Arabia Photon Science Institute and The Henry Royce Institute University of Manchester Manchester M13 9PL United Kingdom BioAFM Facility Faculty of Biology Medicine and Health University of Manchester Stopford Building Oxford Road Manchester M13 9PT United Kingdom Department of Electrical and Electronic Engineering University of Manchester Manchester M13 9PL United Kingdom

Perovskite solar cells (PSCs) continue to attract considerable academic and industrial interest due to their excellent potential to contribute to solar energy generation. The application of PSCs will benefit from improvements in the understanding of the roles of the interfaces present in charge transport and recombination. The buried perovskite/electron transport layer (ETL) interface in n-i-p PSCs is relatively difficult to study, particularly when molecular additives are used to target that region because they are not able to be visualized by electron microscopy. Here, we use sub-micrometer insulating polystyrene microgel particles (PS MGs) to partially cover the ETL of PSCs. The MGs provide well-defined colloidal additives for selectively covering the ETL because they are laterally constrained and the coverage is readily tuneable. We examine the effect of MG concentration on the device performance and find that the MGs passivate the SnO₂ ETL and obstruct charge transport. We then engineer gaps between the deposited MGs using UV/ozone treatment and achieve a maximum power conversion efficiency (PCE) of 20.09% compared to 19.60% for the control. Remarkably, the PSCs can still function efficiently even when the ETL is mostly covered by the MGs. We show that the most efficient devices have partially covered ETLs with a lateral blocking distance of ∼500 nm. This work demonstrates that mostly covering the ETL with insulating particles does not necessarily lead to a catastrophic decrease in performance. In contrast, this study provides a new scalable method for improving the PCE and for potentially enhancing light management for PSCs in the future. © 2024 RSC.

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Macromolecule-Enriched Solvation Enabling High-Voltage Sodium-Ion Batteries

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Angewandte Chemie 2025年

作者： Zhiming Zhao Chen Liu Tianxing Lai Zehao Cui Arumugam Manthiram Materials Science and Engineering Program and Walker Department of Mechanical Engineering The University of Texas at Austin Austin TX 78712 USA

Sodium-ion batteries (SIBs) are emerging as a viable alternative for sustainable and cost-effective energy storage, yet their energy density is curtailed by relatively low voltage outputs (< 4 V) due to the lack of high-voltage electrolytes. Here, for the first time, we describe a high-voltage Na + electrolyte featuring a macromolecule-enriched solvation architecture. The vulnerable small molecules in the Na + solvation shell are replaced by macro polyamide (PA) molecules with high thermodynamic resilience, ensuring a wide electrochemical stability window for the electrolytes with suppressed oxidative/reductive decomposition. Concomitantly, the anions engage in H-bonding with the amido groups of PA, which not only stabilizes the anions against hydrolysis, but also delivers a high Na + transference number of 0.93. Importantly, the nitrogen-rich composition of the macromolecule-enriched electrolyte (MEE) fosters the formation of robust nitride interphases that impart enduring stability to both the cathode and anode. As a result, the hard carbon (HC) || NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NFM) full cells demonstrate significant rechargeability even with an ultrahigh cutoff voltage of 4.4 V. Our approach distinctively avoids the use of fluorinated molecules typically found in (localized-) high-concentration electrolytes, presenting a novel principle that could revolutionize high-voltage electrolyte design.

关键词： Hard carbon anode High-voltage electrolyte Layered oxide cathode Sodium-ion batteries Solvation structure

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Three-dimensional construction of hyperuniform, nonhyperuniform, and antihyperuniform disordered heterogeneous materials and their transport properties via spectral density functions

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Physical Review E 2025年第3期111卷 035310-035310页

作者： Wenlong Shi Yang Jiao Salvatore Torquato Materials Science and Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Rigorous theories connecting physical properties of a heterogeneous material to its microstructure offer a promising avenue to guide the computational material design and optimization. The spectral density function χ̃V(k), which can be obtained experimentally from scattering data, enables accurate determination of various transport and wave propagation characteristics, including the time-dependent diffusion spreadability S(t) and effective dynamic dielectric constant εe for electromagnetic wave propagation. Moreover, χ̃V(k) determines rigorous upper bounds on the fluid permeability K. Given the importance of χ̃V(k), we present here an efficient Fourier-space based computational framework to construct three-dimensional (3D) statistically isotropic two-phase heterogeneous materials corresponding to targeted spectral density functions. In particular, we employ a variety of analytical functional forms for χ̃V(k) that satisfy all known necessary conditions to construct disordered stealthy hyperuniform, standard hyperuniform, nonhyperuniform, and antihyperuniform two-phase heterogeneous material systems at varying phase volume fractions. We show that by tuning the correlations in the system across length scales via the targeted functions, one can generate a rich spectrum of distinct structures within each of the above classes of materials. Importantly, we present the first realization of antihyperuniform two-phase heterogeneous materials in 3D, which are characterized by autocovariance function χV(r) with a power-law tail, resulting in microstructures that contain clusters of dramatically different sizes and morphologies. We also determine the diffusion spreadability S(t) and estimate the fluid permeability K associated with all of the constructed materials directly from the corresponding spectral densities. Although it is well established that the long-time asymptotic scaling behavior of S(t) only depends on the functional form of χ̃V(k), with the stealthy hyperuniform a

关键词： Spectral density

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Deciphering the Impact of Polysulfide Solvation Structure on Electrical Double Layer Chemistry in Sodium–Sulfur Batteries

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Angewandte Chemie 2025年

作者： Weiqi Yao Min-Hao Pai Arumugam Manthiram Materials Science and Engineering Program & Walker Department of Mechanical Engineering The University of Texas at Austin Austin Texas 78712 USA

Room-temperature sodium–sulfur (RT Na–S) batteries are garnering attention for large-scale energy storage. However, their practical application is hindered by challenges, such as the shuttle effect of sodium polysulfides (NaPS) and dendrite growth. The high solubility of NaPS in the electrolyte is particularly problematic. It disrupts electron transfer and obstructs mass transport in the electrical double layer (EDL) region. The EDL plays a pivotal role in governing the interfacial chemistry between the electrode and electrolyte, significantly impacting the overall electrochemical performance. Through simulations and experimental screening of various solvents, including 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), and tetrahydropyran (THP), along with ethyl 1,1,2,2-tetrafluoroethyl ether (ETFE) as a diluent, the relationship between NaPS solvation structure and EDL chemistry has been elucidated. Our findings reveal that THP-based localized high-concentration electrolyte (LHCE) not only reduces the solubility of NaPS by altering its solvation structure but also promotes the formation of a stable inorganic solid-electrolyte interphase (SEI) and improves compatibility with sodium metal. Consequently, Na–S batteries with LHCE-THP/ETFE exhibit long-term stability over 500 cycles at 1C rate with a capacity decay rate of only 0.07% per cycle. This study provides a methodology for designing electrolytes based on molecular structure, polysulfide solvation properties, and EDL interfacial chemistry.

关键词： Electrical double layer Electrolytes Polysulfide solvation structure Shuttle effect Sodium–sulfur batteries

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