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SSRN 2022年

作者： Ibrahim, Nura Ahmed, Ridwan A. Adri, Huda Reisya, Ichwani Department of Physics Ahmadu Bello University Zaria Nigeria Materials Science and Engineering Program Department of Mechanical Engineering Worcester Polytechnic Institute WorcesterMA01609 United States

We present a theoretical investigation on the electronic structures and the thermoelectric properties of doped ZrCoBi half-Heusler compound using a combination of density functional theory calculations, semi classical Boltzmann transport theory and deformation potential theory. The effect of doping is described by a combination of rigid band approximation (RBA) and a model that explicitly includes the dopant atom within the lattice of ZrCoBi. The results demonstrate a high power factor with considerable n- and p-doping concentrations at high temperatures. Our findings further reveal that the electronic transport coefficients of ZrCo0.75M0.25Bi (M = Ni, Pd, Pt) are comparable because of their identical electronic structures. At 900 K, a high figure of merit (ZT) of ~ 0.35, ~ 0.38, and ~ 0.40 are obtained for ZrCo0.75Ni0.25Bi, ZrCo0.75Pd0.25Bi and ZrCo0.75Pt0.25Bi respectively. © 2022, The Authors. All rights reserved.

关键词： Electronic structure

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Bridging scales with Machine Learning: From first principles statistical mechanics to continuum phase field computations to study order-disorder transitions in LixCoO2

arXiv

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arXiv 2023年

作者： Teichert, G.H. Das, S. Shojaei, M. Faghih Holber, J. Mueller, T. Hung, L. Gavini, V. Garikipati, K. Department of Mechanical Engineering University of Michigan United States Toyota Research Institute Los AltosCA United States Department of Materials Science & Engineering University of Michigan United States Department of Mathematics University of Michigan United States Michigan Institute for Computational Discovery & Engineering University of Michigan United States Applied Physics Program University of Michigan United States Materials Science & Engineering Johns Hopkins University United States

LixTMO2 (TM=Ni, Co, Mn) forms an important family of cathode materials for Li-ion batteries, whose performance is strongly governed by Li composition-dependent crystal structure and phase stability. Here, we use LixCoO2 (LCO) as a model system to benchmark a machine learning-enabled framework for bridging scales in materials physics. We focus on two scales: (a) assemblies of thousands of atoms described by density functional theory-informed statistical mechanics, and (b) continuum phase field models to study the dynamics of order-disorder transitions in LCO. Central to the scale bridging is the rigorous, quantitatively accurate, representation of the free energy density and chemical potentials of this material system by coarsegraining formation energies for specific atomic configurations. We develop active learning workflows to train recently developed integrable deep neural networks for such high-dimensional free energy density and chemical potential functions. The resulting, first principles-informed, machine learning-enabled, phase-field computations allow us to study LCO cathodes’ phase evolution in terms of temperature, morphology, charge cycling and particle size. © 2023, CC BY-NC-SA.

关键词： Cathodes

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Microstructural analysis and electro-optic properties of thick epitaxial BaTiO3 films integrated on silicon (001)

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Physical Review materials 2022年第9期6卷 095201-095201页

作者： Marc Reynaud Zuoming Dong Hyoju Park Wente Li Agham B. Posadas Jamie H. Warner Daniel Wasserman Alexander A. Demkov Department of Physics University of Texas at Austin Austin Texas 78712 USA Department of Electrical and Computer Engineering University of Texas at Austin Austin Texas 78758 USA Walker Department of Mechanical Engineering University of Texas at Austin Austin Texas 78712 USA Materials Science and Engineering Program and Texas Materials Institute The University of Texas at Austin Texas 78712 USA

Recent advances in epitaxial oxide deposition have enabled the fabrication of thick films of ferroelectric perovskite BaTiO3 capable of providing a robust electro-optic response via the Pockels effect in silicon photonic devices. We report a microstructure analysis of such films integrated on Si(001) by molecular beam epitaxy, showing how the crystallographic and polarization orientation change as a function of thickness. The measured electro-optic properties of the film correlate well with the microstructural analysis and demonstrate the potential of Si-integrated BaTiO3 for silicon photonics. An effective Pockels coefficient of up to 268 pm/V has been demonstrated in 110-nm-thick films in transmission measurements and 352 pm/V in waveguide measurements.

关键词： Ferroelectricity Photonics Epitaxy

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Sample Preconcentration Through Airjet-Induced Liquid Phase Enrichment

SSRN

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SSRN 2023年

作者： Wang, Edward Laurent, Louise C. Hall, Drew A. Lo, Yu-Hwa Department of Aerospace and Mechanical Engineering Materials Science and Engineering Program University of California La Jolla San DiegoCA United States Sanford Consortium of Regenerative Medicine United States Department of Electrical and Computer Engineering University of California La Jolla San DiegoCA United States Department of Bioengineering

Sample preparation is essential for nucleic acid assays, affecting their sensitivity and reliability. However, this process often results in a significant loss or dilution of the analyte, which becomes a bottleneck that limits downstream assay performance, particularly for assays that accept a limited input sample volume. To overcome this challenge, we present an evaporative-based sample enrichment method that uses an airjet to concentrate analytes within a small, defined volume by reversing the coffee-ring effect. A small, concentrated sample can then be collected for analysis to increase the initial sample load. The effectiveness of the reported airjet enrichment was quantified using qPCR of λ-DNA, HeLa-S3 RNA, and heat-inactivated SARS-CoV-2 samples. Comparisons between airjet enrichment and conventional evaporative concentration methods demonstrated significant advantages of airjet enrichment, including the ability to concentrate a high percentage of analyte within a 1 µL volume. The enrichment method was then integrated and adapted for various fluid volumes commonly found in nucleic acid sample preparation procedures. Here, airjet enrichment reduced the overall [[EQUATION]] by an average of 9.27 cycles for each analyte, resulting in a 600-fold enrichment from the initial concentration. In addition, to perform selective enrichment and prevent salt-based interference in downstream analysis, PEG was added to reduce the co-enrichment of salt. These studies show how airjet enrichment technology can be easily integrated into existing laboratory protocols with minimal modification and significantly improve the performance of nucleic acid amplification assays. © 2023, The Authors. All rights reserved.

关键词： Biomolecules

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Effect of serrated grain boundary on tensile and creep properties of a precipitation strengthened high entropy alloy

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science and Technology of Advanced materials 2023年第1期24卷 Article: 2158043页

作者： Lee, Jhuo-Lun Wang, Pei-Te Lo, Kai-Chi Shen, Pai-Keng Tsou, Nien-Ti Kakehi, Koji Murakami, Hideyuki Tsai, Che-Wei Gorsse, Stéphane Yeh, An-Chou High Entropy Materials Center National Tsing Hua University Hsinchu Taiwan Program in Prospective Functional Materials Industry National Tsing Hua University Hsinchu Taiwan Department of Materials Science and Engineering National Tsing Hua University Hsinchu Taiwan Department of Materials Science and Engineering National Yang Ming Chiao Tung University Hsinchu Taiwan Department of Mechanical Engineering Tokyo Metropolitan University Tokyo Hachiojishi Japan Research Center for Structural Materials National Institute for Materials Science Tsukuba Japan Department of Nanoscience and Nanoengineering Waseda University Tokyo Shinjuku Japan CNRS University of Bordeaux Bordeaux INP ICMCB UMR 5026 Pessac France

In this study, tensile and creep deformation of a high-entropy alloy processed by selective laser melting (SLM) has been investigated;hot ductility drop was identified at first, and the loss of ductility at elevated temperature was associated with intergranular fracture. By modifying the grain boundary morphology from straight to serration, the hot ductility drop issue has been resolved successfully. The serrated grain boundary could be achieved by reducing the cooling rate of solution heat treatment, which allowed the coarsening of L12 structured γ′ precipitates to interfere with mobile grain boundaries, resulting in undulation of the grain boundary morphology. Tensile and creep tests at 650°C were conducted, and serrated grain boundary could render a significant increase in tensile fracture strain and creep rupture life by a factor of 3.5 and 400, respectively. Detailed microstructure analysis has indicated that serrated grain boundary could distribute strains more evenly than that of straight morphology. The underlying mechanism of deformation with grain boundary serration was further demonstrated by molecular dynamic simulation, which has indicated that serrated grain boundaries could reduce local strain concentration and provide resistance against intergranular cracking. This is the first study to tackle the hot ductility drop issue in a high-entropy alloy fabricated by SLM;it can provide a guideline to develop future high-entropy alloys and design post heat treatment for elevated temperature applications. © 2023 The Author(s). Published by National Institute for materials science in partnership with Taylor & Francis Group.

关键词： Grain boundaries

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Optimizing dispersion of torrefied spent coffee grounds for enhanced biochar-EVA composite properties through sodium percarbonate-assisted treatment

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Journal of Industrial and engineering Chemistry 2025年

作者： Lee, Kuan-Ting Gabriela, Situmorang Chen, Wei-Hsin Rajendran, Saravanan Selvarajoo, Anurita Department of Chemical and Materials Engineering Tunghai University Taichung407 Taiwan International Master Degree Program on Energy Engineering National Cheng Kung University Tainan701 Taiwan Department of Aeronautics and Astronautics National Cheng Kung University Tainan701 Taiwan Research Center for Smart Sustainable Circular Economy Tunghai University Taichung407 Taiwan Department of Mechanical Engineering National Chin-Yi University of Technology Taichung411 Taiwan Instituto de Alta Investigación Universidad de Tarapacá Arica1000000 Chile Department of Civil Engineering Faculty of Science and Engineering University of Nottingham Malaysia

This study aims to optimize biochar by combining 10 % sodium percarbonate with 90 % spent coffee grounds and torrefying at 300 °C for 30 min. Biochar enhances black color dispersion in a composite when blending the optimal biochar and ethylene vinyl acetate. The maximum carbon content of the optimal biochar is 59.97 %, exhibiting similar dispersion, packing density, pore size, and contact angle to carbon black. The optimal biochar's specific surface area and total pore volume are 7.12 m2·g−1 and 0.0018 cm3·g−1, respectively, 2.9 times and 1.2 times that of untreated torrefied spent coffee grounds with SP treated. The mechanical properties of the composite, which is blended with 15 wt% of the optimal biochar to ethylene vinyl acetate through trade-off analysis, indicate a tensile strength and Young's modulus of 1.03 MPa and 9.69 MPa, respectively. As the amount of blended optimal biochar increases, the tensile strength decreases while Young's modulus increases. Compared with a composite blended with the same 15 wt% of carbon black, the tensile strength and Young's modulus are 0.77 MPa and 9.55 MPa, respectively. In conclusion, the optimal biochar is a potential alternative material that could replace carbon black. This finding aligns with the developmental direction of achieving negative carbon emissions, promoting a circular economy and valorizing waste. © 2025 The Korean Society of Industrial and engineering Chemistry

关键词： Tensile strength

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Deep Brain Optoacoustic Stimulation Enabled by a Multifunctional Fiber-based Optoacoustic Emitter

Deep Brain Optoacoustic Stimulation Enabled by a Multifuncti...

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Optics and the Brain, BRAIN 2022

作者： Zheng, Nan Jiang, Ying Jiang, Shan Li, Yueming Jia, Xiaoting Yang, Chen Cheng, Ji-Xin Division of Materials Science and Engineering Boston University BostonMA02215 United States Graduate Program for Neuroscience Boston University BostonMA02215 United States Photonics Center Boston University BostonMA02215 United States Department of Mechanical Engineering Boston University BostonMA02215 United States Department of Biomedical Engineering Boston University BostonMA02215 United States Department of Chemistry BostonMA02215 United States

Optoacoustic neurostimulation is a non-genetic light-mediated technique allows high precise control of neural activities. Here, we combined optoacoustic stimulation and electrophysiological recording to achieve bidire... 详细信息

ISBN: (纸本)9781957171036

关键词： Electrophysiology

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Influence of Treatment Time on the Synthesis of Copper Oxide Films by Cathode Cage Plasma Deposition

SSRN

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SSRN 2023年

作者： de Carvalho, Júlio F.S. Monção, Renan M. de Sousa, Ediones M. da Luz Lima, Cleânio Costa, Carla L.S.C. Garcia, Ramón R.P. Feitor, Michelle C. de Carvalho Costa, Thércio H. Libório, Maxwell S. de Sousa, Rômulo R.M. Federal University of Piauí Graduate Program in Materials Science and Engineering PI Teresina Brazil Federal University of Piauí Physics Postgraduate Program PI Teresina Brazil Federal university of Rio Grande do Norte Department of Materials Science and Engineering RN Natal Brazil Federal University of Rio Grande do Norte Department of Mechanical Engineering RN Natal Brazil Federal university of Rio Grande do Norte School of Science and Technology RN Natal Brazil

Copper oxide is a valuable p-type semiconductor for photovoltaic applications. In this work, plasma deposition with cathodic cage (CCPD) of copper oxide (CuO+Cu2O) films on glass was performed to evaluate the microstructural, morphological, chemical, and bandgap changes as a function of the treatment time variation (2, 3, 4, and 5 hours). The samples were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive System (EDS), X-ray Diffraction (XRD), and Raman Spectroscopy to identify morphologies, chemical composition, and crystalline phases of the deposited films, and the absorption spectrum optics was used to calculate the bandgap width. All films showed bandgap energies around 2.60 eV. However, the sample treated with a time of 3h presented a compact coating with 1.46 µm of thickness and bandgap energy equal to 2.57 eV, being the best result. © 2023, The Authors. All rights reserved.

关键词： Energy gap

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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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Phase Transitions of the CU6Sn5 Phase Under Electric Currents

Phase Transitions of the CU6Sn5 Phase Under Electric Current...

引用

International Conference on Electronics Packaging (ICEP)

作者： Shubhayan Mukherjee Yu-Chen Liu Shih-Kang Lin Department of Materials Science and Engineering National Cheng Kung University Tainan Taiwan Hierarchical Green-Energy Materials (Hi-GEM) Research Centre National Cheng Kung University Tainan Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan Taiwan Department of Mechanical Engineering National Cheng Kung University Tainan Taiwan

ISBN: (数字)9784991191190

ISBN: (纸本)9798331514747

The performance and reliability of interfacial regions in electronic solder joints are critical for the durability of lead-free solder systems. The intermetallic compound $\text{Cu}_{6}\text{Sn}_{5}$ , which forms at the interface between Sn-based solders and Cu substrates, exists in two crystal structures: the low-temperature monoclinic phase $(\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5})$ and the high-temperature hexagonal phase $(\eta-\text{Cu}_{6}\text{Sn}_{5})$ . Although the thermal behavior of these phases is well-documented, the effects of electric current on the stability and mechanical properties of $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ remain less understood. This study investigates the impact of electric current on the microstructural evolution of $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ through high-resolution transmission electron microscopy (HR-TEM) following the synchrotron radiation-based X-ray diffraction (SR-XRD). Single-phase $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ samples were subjected to a current density of 1.5 x 10 3 A/cm 2 for 5 hours. Microstructural observations from HR-TEM, following SR-XRD, reveal significant insights into the behavior of monoclinic $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ under electric current stressing. These findings offer insights into the relationship between electric current and phase stability in interfacial compounds, which could enhance the reliability of solder joints in advanced electronic systems.

关键词： X-ray scattering Synchrotrons High-resolution transmission electron microscopy materials reliability X-ray diffraction Stability analysis Compounds Current Soldering Thermal stability

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