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Ab initio phonon transport across grain boundaries in graphene using machine learning based on small dataset

Physical Review materials 2022年第4期6卷 044004-044004页

作者： Amirreza Hashemi Ruiqiang Guo Keivan Esfarjani Sangyeop Lee Computational Modeling and Simulation Program University of Pittsburgh Pittsburgh Pennsylvania 15261 USA Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh Pennsylvania 15261 USA Department of Mechanical and Aerospace Engineering University of Virginia Charlottesville Virginia 22904 USA Department of Materials Science and Engineering University of Virginia Charlottesville Virginia 22904 USA Department of Physics University of Virginia Charlottesville Virginia 22904 USA Department of Physics and Astronomy University of Pittsburgh Pittsburgh Pennsylvania 15261 USA

Establishing the structure-property relationship for grain boundaries (GBs) is critical for developing next-generation functional materials but has been severely hampered due to its extremely large configurational space. Atomistic simulations with low computational cost and high predictive power are strongly desirable, but the conventional simulations using empirical interatomic potentials and density functional theory suffer from the lack of predictive power and high computational cost, respectively. A machine learning interatomic potential (MLIP) recently emerged but often requires extensive size of the training dataset, making it a less feasible approach. Here, we demonstrate that an MLIP trained with a rationally designed small training dataset can predict thermal transport across GBs in graphene with ab initio accuracy at an affordable computational cost. We employed a rational approach based on the structural unit model to find a small set of GBs that can represent the entire configurational space and thus can serve as a cost-effective training dataset for the MLIP. Only 5 GBs were found to be enough to represent the entire configurational space of graphene GBs. Using the atomistic Green's function approach and the MLIP, we revealed that the structure-thermal resistance relation in graphene does not follow the common understanding that large dislocation density causes larger thermal resistance. In fact, thermal resistance is nearly independent of dislocation density at room temperature and is higher when the dislocation density is small at sub-room temperature. We explain this intriguing behavior with the buckling near a GB causing a strong scattering of flexural phonon modes. In this paper, we show that a machine learning technique combined with conventional wisdom (e.g., structural unit model) can extend the recent success of ab initio thermal transport simulation, which has been mostly limited to single crystals, to complex yet practically important polycry

关键词： Phonons Graphene Landauer formula Machine learning

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Graphene-Like materials Supported on Sepiolite Clay Synthesized at Relatively Low Temperature

SSRN

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SSRN 2023年

作者： Ferreira, Paula Barra, Ana Lazăr, Oana Mihai, Geanina Bratu, Cătălina Ruiz-García, Cristina Darder, Margarita Aranda, Pilar Enăchescu, Marius Nunes, Cláudia Ruiz-Hitzky, Eduardo CICECO – Aveiro Institute of Materials Department of Materials and Ceramic Engineering University of Aveiro Aveiro3810-193 Portugal Materials Science Institute of Madrid CSIC c/Sor Juana Inés de la Cruz 3 Madrid28049 Spain Center for Surface Science and Nanotechnology University Politehnica of Bucharest Bucharest060042 Romania Chemical Engineering Department Faculty of Science Universidad Autónoma de Madrid Madrid28049 Spain Academy of Romanian Scientists Splaiul Independentei 54 Bucharest050094 Romania

The preparation of solids with graphitic structure usually requires synthesis procedures using very high temperatures. In this work, a comparative study involving different experimental strategies of synthesis at relatively low temperature was carried out to obtain graphene-like materials supported on microporous sepiolite clay. The final objective was the optimization of the development of new clay-graphitic nanostructured materials to achieve conductive and porous solids while saving energy and time during the preparation stages. The pyrolysis of sucrose, used as carbon precursor, was accomplished by microwave (MW) pyrolysis or tube furnace (TF) pyrolysis at 200 or 500 ºC followed by a hydrothermal carbonization (HTC) step. The resulting carbon-clay nanoarchitectures were characterized by Raman and Infrared spectroscopy, X-ray diffraction, elemental analysis, electron microscopy, and nitrogen adsorption-desorption isotherms. The MW200 and TF200 treatments caramelized sucrose and the post-HTC step was fundamental to obtain porous carbonaceous materials. The TF500 pyrolysis produced predominantly crystalline carbon, while the MW500 pyrolysis formed an amorphous material. Moreover, the high-resolution transmission electron microscopy observations of TF500 sample revealed a crystalline material with a d-spacing of 0.33 nm, matching the graphitic lattice. All the treatment conditions performed at 500 ºC i.e., MW or TF followed or not by HTC, resulted in mesoporous carbons with a specific surface area above 200 m2·g-1. The MW pyrolysis saved 100 min of the reaction time in comparison to TF pyrolysis to obtain the carbonaceous porous materials. © 2023, The Authors. All rights reserved.

关键词： Graphene

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Electro-Polymerization Process with Double-Sided Electrodes for Supercapacitors

Electro-Polymerization Process with Double-Sided Electrodes ...

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International Flexible Electronics Technology Conference (IFETC)

作者： Nandu Koripally Lulu Yao Naresh Eedugurala Jason D. Azoulay Tse Nga Ng Department of Electrical and Computer Engineering University of California San Diego La Jolla CA USA Materials Science Engineering Program University of California San Diego La Jolla CA USA Chemisty Department Georgia Institute of Technology Atlanta GA USA

Supercapacitors are known for longer cycle life and faster charging rate compared to batteries. However, the energy density of supercapacitors requires improvement to expand their application space. To raise the energy density of redox supercapacitors, this work demonstrates electro-polymerization on both sides of electrodes to increase material loading, reduce overall device mass, and consequently increase the capacitance, power, and energy density of supercapacitors. We achieved an energy density of 1823 mWh kg -1 and a power density of 16.5 W kg -1 with a wide potential window of 3 V.

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Interfacial thermal transport in spin caloritronic material systems

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Physical Review materials 2021年第11期5卷 114403-114403页

作者： Frank Angeles Qiyang Sun Victor H. Ortiz Jing Shi Chen Li Richard B. Wilson Department of Mechanical Engineering and Materials Science and Engineering Program University of CaliforniaRiverside California 92521 USA Department of Physics and Astronomy Program University of California Riverside California 92521 USA

Interfaces often govern the thermal performance of nanoscale devices and nanostructured materials. As a result, accurate knowledge of thermal interface conductance is necessary to model the temperature response of nanoscale devices or nanostructured materials to heating. Here, we report the thermal boundary conductance between metals and insulators that are commonly used in spin-caloritronic experiments. We use time-domain thermoreflectance to measure the interface conductance between metals such as Au, Pt, Ta, Cu, and Al with garnet and oxide substrates, e.g., NiO, yttrium iron garnet (YIG), thulium iron garnet (TmIG), Cr2O3, and sapphire. We find that, at room temperature, the interface conductance in these types of material systems range from 50 to 300MWm−2K−1. We also measure the interface conductance between Pt and YIG at temperatures between 80 and 350 K. At room temperature, the interface conductance of Pt/YIG is 170MWm−2K−1 and the Kapitza length is ∼40 nm. A Kapitza length of 40 nm means that, in the presence of a steady-state heat current, the temperature drop at the Pt/YIG interface is equal to the temperature drop across a 40-nm-thick layer of YIG. At 80 K, the interface conductance of Pt/YIG is 60MWm−2K−1, corresponding to a Kapitza length of ∼300 nm.

关键词： Thermal conductivity

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Investigating the impact of metal ion variations in terephthalate metal–organic frameworks on the organic solvent nanofiltration performance of mixed matrix membranes

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Journal of Membrane science 2024年 700卷

作者： Ajebe, Eyasu Gebrie Hu, Chien Chieh Lugito, Graecia Hu, Chun-Po Hung, Wei-Song Lee, Kueir-Rarn Lai, Juin-Yih Graduate Institute of Applied Science and Technology Advanced Membrane Materials Research Center National Taiwan University of Science and Technology Taipei Taiwan Chemical Engineering Study Program Faculty of Industrial Technology Institut Teknologi Bandung West Java Indonesia Nanyang Technological University 1 Cleantech Loop Singapore R&D Center for Membrane Technology Chung Yuan University Chungli Taoyuan Taiwan Department of Chemical Engineering and Materials Science Yuan Ze University Chungli Taoyuan Taiwan

Nano-fillers integrated into mixed matrix membranes (MMMs) present promising alternatives for organic solvent nanofiltration (OSN). In this work, our objective is to enhance OSN performance by incorporating terephthalate metal-organic frameworks (M-BDC, where M = Zr or Cu) into a P84 matrix to fabricate M-BDC/P84 composite MMMs. This work focuses on the influence of metal cluster variation on particle size, pore size distribution, and specific surface area of M-BDC, while systematically investigating the impact of M-BDC addition on OSN performance and underlying separation mechanisms. The synthesized membranes underwent comprehensive characterization using SEM, XRD, ATR-FTIR, contact angle, zeta potential, and thermogravimetric analysis. Significantly, all MMMs exhibited superior permeance and methyl blue (MB) rejection compared to P84 membranes. This enhancement is attributed to the improved interfacial contact between M-BDC and P84, as well as their effective dispersion within the membrane matrix. Interestingly, comparative analysis between Cu-BDC/P84 and Zr-BDC/P84 MMMs revealed the latter's superior permeance, attributed to its larger pore size and surface area. The resulting MMMs demonstrated outstanding MB rejection (>96.7%) with ethanol permeance of 21.5 and 19.0 LMH/Bar for Zr-BDC/P84 and Cu-BDC/P84 MMMs, respectively. Furthermore, the stable performance of M-BDC-based MMMs during prolonged MB/ethanol operation underscores their potential significance in the field of OSN, providing valuable insights for future membrane design and application. © 2024 Elsevier B.V.

关键词： Organometallics

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Preparation and Characterization of Nanopatterned Polycaprolactone/Cellulose Nanocrystal Composite Membranes for Cardiovascular Tissue engineering 15

Preparation and Characterization of Nanopatterned Polycaprol...

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15th IEEE International Conference on Nano/Molecular Medicine and engineering, NANOMED 2021

作者： Batta-Mpouma, Joseph Kandhola, Gurshagan Kuczwara, Patrick Chivers, Cody Kim, Woochan Jensen, Hanna Kim, Jangho Jensen, Morten Kim, Jin-Woo Materials Science & Engineering Program Institute For Nanoscience & Engineering University of Arkansas Department of Biological & Agricultural Engineering FayettevilleAR United States Engineering And Institute For Nanoscience & Engineering University of Arkansas Department of Biological & Agricultural FayettevilleAR United States Institute For Nanoscience & Engineering University of Arkansas FayettevilleAR United States Chonnam National University Department of Rural & Biosystems Engineering Gwangju Korea Republic of University of Arkansas Department of Biomedical Engineering FayettevilleAR United States

ISBN: (纸本)9781665458566

Cardiac tissue exhibits very low regenerative capacity. Polymeric tissue scaffolds designed for repair of damaged cardiac tissue need to have the right balance of mechanical and biological characteristics that are necessary to withstand inherent stresses generated by cyclic contraction of cardiomyocytes and to promote cell attachment and growth. Polycaprolactone (PCL), a biocompatible polymer with low biodegradability, is a promising material to develop scaffolds for tissue engineering (TE). However, its high stiffness limits its use as a matrix for cardiovascular TE. In this work, we evaluated the physical, mechanical and surface properties of PCL and cellulose nanocrystal (CNC) composite membranes, imprinted with a three-dimensional groove-ridge pattern, and their potential for cardiomyocyte adhesion and growth. This work demonstrates the impact of (a) incorporating CNCs within the PCL matrix and (b) patterning the membrane, on the surface roughness, wettability, and mechanical properties of composites, with an aim to alleviate the limitations of pure PCL scaffolds for cardiac TE applications. © 2021 IEEE.

关键词： Biocompatibility

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Connecting polymer collapse and the onset of jamming

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Physical Review E 2024年第3期109卷 034406-034406页

作者： Alex T. Grigas Aliza Fisher Mark D. Shattuck Corey S. O'Hern Graduate Program in Computational Biology and Bioinformatics Yale University New Haven Connecticut 06520 USA Integrated Graduate Program in Physical and Engineering Biology Yale University New Haven Connecticut 06520 USA Department of Mechanical Engineering and Materials Science Yale University New Haven Connecticut 06520 USA Benjamin Levich Institute and Physics Department The City College of New York New York New York 10031 USA Department of Physics Yale University New Haven Connecticut 06520 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA

Previous studies have shown that the interiors of proteins are densely packed, reaching packing fractions that are as large as those found for static packings of individual amino-acid-shaped particles. How can the interiors of proteins take on such high packing fractions given that amino acids are connected by peptide bonds and many amino acids are hydrophobic with attractive interactions? We investigate this question by comparing the structural and mechanical properties of collapsed attractive disk-shaped bead-spring polymers to those of three reference systems: static packings of repulsive disks, of attractive disks, and of repulsive disk-shaped bead-spring polymers. We show that the attractive systems quenched to temperatures below the glass transition T≪Tg and static packings of both repulsive disks and bead-spring polymers possess similar interior packing fractions. Previous studies have shown that static packings of repulsive disks are isostatic at jamming onset, i.e., the number of interparticle contacts Nc matches the number of degrees of freedom, which strongly influences their mechanical properties. We find that repulsive polymer packings are hypostatic at jamming onset (i.e., with fewer contacts than degrees of freedom) but are effectively isostatic when including stabilizing quartic modes, which give rise to quartic scaling of the potential energy with displacements along these modes. While attractive disk and polymer packings are often considered hyperstatic with excess contacts over the isostatic number, we identify a definition for interparticle contacts for which they can also be considered as effectively isostatic. As a result, we show that the mechanical properties (e.g., scaling of the potential energy with excess contact number and low-frequency contribution to the density of vibrational modes) of weakly attractive disk and polymer packings are similar to those of isostatic repulsive disk and polymer packings. Our results demonstrate that static

关键词： Jamming Polymer folding Protein folding Single polymer chains

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Lithium-ion battery functionality over broad operating conditions via local high concentration fluorinated ester electrolytes

RSC Applied Interfaces

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RSC Applied Interfaces 2024年第5期1卷 1077-1092页

作者： Quilty, Calvin D. Marin Bernardez, Edelmy J. Nicoll, Andrew Hossain, MD Jamil Kingan, Arun Arnot, David J. Mohamed, Hafsa A. Tong, Xiao Jaye, Cherno Fischer, Daniel A. Wang, Lei Qi, Yue Takeuchi, Esther S. Marschilok, Amy C. Yan, Shan Bock, David C. Takeuchi, Kenneth J. Department of Chemistry Stony Brook University Stony Brook 11794 NY United States Institute of Energy: Sustainability Environment and Equity (I:SEE) Stony Brook University Stony Brook 11794 NY United States School of Engineering Brown University Providence 02912 RI United States Department of Materials Science and Chemical Engineering Stony Brook University Stony Brook 11794 NY United States Science Undergraduate Laboratory Internship (SULI) Program Brookhaven National Laboratory Upton 11973 NY United States Department of Chemistry University of Rochester Rochester 14627 NY United States Department of Chemistry The College of Wooster Wooster 44691 OH United States Center for Functional Nanomaterials Brookhaven National Laboratory Upton 11973 NY United States Material Measurement Laboratory National Institute of Standards and Technology Gaithersburg 20899 MD United States Interdisciplinary Science Department Brookhaven National Laboratory Upton 11973 NY United States

Facilitating widespread adoption of electric vehicles will require next-generation battery systems that can operate reliably over a large temperature range, at high operating voltage, and under fast charging rates. Herein, a novel class of nonflammable fluorinated ester-based local high concentration electrolytes (LHCEs) are described. When cycled in commercially relevant graphite/LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) pouch cells, these electrolytes demonstrate improved capacity retention compared to carbonate-based electrolytes under multiple usage conditions including high voltage (4.5 V), fast charge (4C, 15 minutes), and low temperature (−20 °C) without sacrificing capacity retention at elevated temperature (40 °C). Low carbon, high fluoride cathode electrolyte interphases formed by the LHCE system yield a significant reduction in charge transfer impedance during cycling and contribute to capacity retention. These results demonstrate that using fluorinated esters in a LHCE modality enables creation of a new class of nonflammable electrolytes that can successfully operate over broad operating conditions. © 2024 RSC.

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The effect of the addition of alumina on the viscosity, surface tension, and foaming efficiency of 2.5(CaO/SiO2)-xAl2O3-yFeO-MgO melts

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ceramics International 2023年第13期49卷 21994-22003页

作者： Chang, Yu-En Lin, Chi-Ming Shen, Jyun-Ming Luo, Shao-Feng Yu, Kai-Wen Wu, Weite Department of Materials Science and Engineering National Chung Hsing University 145 Xingda Rd South Dist Taichung City40227 Taiwan WEI CHIH STEEL INDUSTRIAL CO. LTD No.123 Nanbu Guantian Dist. Tainan City720006 Taiwan Academy of Circular Economy Industrial and Intelligent Technology Program National Chung Hsing University No. 15 Guangming Rd. Nantou County 540 Taiwan

Viscosity and surface tension strongly influence the efficiency of slag foam in metallurgical processes. An excellent foaming slag preserves heat and lowers the cost of smelting in an electric furnace. In this study, we investigated the viscosity, surface tension, and foaming efficiency of a 2.5CaO/SiO2-xAl2O3-yFeO-MgO slag. We also investigated the different valence oxygen ions by X-ray photoelectron spectroscopy (XPS). The results showed that with a gradual increase in the content of Al2O3, the viscosity initially increased and then decreased, and the changes in surface tension followed a similar pattern. The change in viscosity was caused by the increase in the degree of polymerization of the slag, which was determined by the competitive relationship between polymerization and the reduction in the stability of the overall network structure. Adding a small amount of Al2O3 to the slag slightly increased the number of Al–O–Al structures, whereas adding a large amount of the Al2O3 led to the formation of low-strength Al–O–Si structures, which reduced the stability of the network structure, thus reducing the viscosity. Because the surface tension is related to the concentration of non-bridging oxygens (NBOs), when the NBO content increased, the instability of the surface structure caused an increase in energy, thus increasing the surface tension. In addition, the CaO–SiO2–5MgO-xAl2O3-yFeO five-element oxide in this study had the lowest surface tension at the same NBO concentration, which positively contributed to slag foaming. Finally, When the Al2O3 content in the system increased from 5.1 to 15.7 wt%, the foaming efficiency increased from 24.2 to 69.2 (minute‧centimeters), an increase of 286%. © 2023 Elsevier Ltd and Techna Group S.r.l.

关键词： Silica

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Ultrafast measurements of the interfacial spin Seebeck effect in Au and rare-earth iron-garnet bilayers

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Physical Review materials 2021年第7期5卷 074401-074401页

作者： Víctor H. Ortiz Michael J. Gomez Yawen Liu Mohammed Aldosary Jing Shi Richard B. Wilson Department of Mechanical Engineering and Materials Science and Engineering Program University of California Riverside California 92521 USA Department of Physics and Astronomy Program University of California Riverside California 92521 USA

We investigate picosecond spin currents across Au/iron-garnet interfaces in response to ultrafast laser heating of the electrons in the Au film. In the picoseconds after optical heating, interfacial spin currents occur due to an interfacial temperature difference between electrons in the metal and magnons in the insulator. We report measurements of this interfacial longitudinal spin Seebeck effect between Au and rare-earth iron-garnet insulators, i.e., RE3Fe5O12, where RE is Y, Eu, Tb, Tm. By systematically varying the rare-earth element, we modify the total magnetic moment of the iron garnet. We use time-domain thermoreflectance measurements to characterize the thermal response of the bilayer to ultrafast optical heating. We use time-resolved magneto-optic Kerr effect measurements of the Au layer to measure the time evolution of spin accumulation in the Au film. Replacing Y with other rare earths enhances the electron-magnon conductance Ge−m at the Au iron-garnet interface by as much as a factor of 3. The electron-magnon conductance does not follow the trend of either the total magnetization of the iron garnet or the magnetic moment of the rare earth.

关键词： Magneto-optical Kerr effect Magnons Spin Seebeck effect Spin polarization Ultrafast magnetic effects

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