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arXiv 2024年

作者： Callahan, William A. Egbo, Kingsley Lee, Cheng-Wei Ginley, David O'Hayre, Ryan Zakutayev, Andriy Materials Science Center National Renewable Energy Laboratory GoldenCO80401 United States Advanced Energy Systems Graduate Program Colorado School of Mines GoldenCO80401 United States Department of Metallurgical and Materials Engineering Colorado School of Mines GoldenCO80401 United States

β-Ga2O3-based semiconductor heterojunctions have recently demonstrated improved performance at high voltages and elevated temperatures and are thus promising for applications in power electronic devices and harsh-environment sensors. However, the long-term reliability of these ultra-wide band gap (UWBG) semiconductor devices remains barely addressed and may be strongly influenced by chemical reactions at the p-n heterojunction interface. Here, we experimentally demonstrate operation and evaluate the reliability of Cr2O3:Mg/β-Ga2O3 p-n heterojunction diodes at during extended operation at 600◦C, as well as after 30 repeated cycles between 25-550◦C. The calculated pO3-temperature phase stability diagram of the Ga-Cr-O material system predicts that Ga2O3 and Cr2O3 should remain thermodynamically stable in contact with each other over a wide range of oxygen pressures and operating temperatures. The fabricated Cr2O3:Mg/β-Ga2O3 p-n heterojunction diodes show room-temperature on/off ratios >104 at ±5V and a breakdown voltage (VBr) of -390V. The leakage current increases with increasing temperature up to 600◦C, which is attributed to Poole-Frenkel emission with a trap barrier height of 0.19 eV. Over the course of a 140-hour thermal soak at 600◦C, both the device turn-on voltage and on-state resistance increase from 1.08V and 5.34 mΩ-cm2 to 1.59V and 7.1 mΩ-cm2 respectively. This increase is attributed to the accumulation of Mg and MgO at the Cr2O3/Ga2O3 interface as observed from TOF-SIMS analysis. These findings inform future design strategies of UWBG semiconductor devices for harsh environment operation and underscore the need for further reliability assessments for β-Ga2O3 based devices. © 2024, CC BY.

关键词： Gallium compounds

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Design, Fabrication, and Characterization of 1-3 Piezoelectric Composite Air-Coupled Ultrasonic Transducers with Micro-Membrane Filter Matching Layer

SSRN

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SSRN 2024年

作者： Wang, Chuanmin Gao, Huayun Zhou, Xinyi Ma, Weigang Tan, Hua Samart, Chanatip Salamon, David Yan, Chunze Zhang, Haibo School of Materials Science and Engineering State Key Laboratory of Material Processing and Die & Mould Technology Huazhong University of Science and Technology Wuhan430074 China Engineering Research Center of Ceramic Materials for Additive Manufacturing Ministry of Education Wuhan430074 China Guangdong HUST Industrial Technology Research Institute Dongguan523808 China Department of Chemistry Faculty of Science and Technology Thammasat University Pathumthani12120 Thailand Central European Institute of Technology Brno University of Technology Brno Czech Republic Faculty of Chemical Engineering Industrial University of Ho Chi Minh City Ho Chi Minh City71420 Viet Nam

Air-coupled ultrasonic transducers are widely used in various fields of nondestructive material characterization. This paper presents the fabrication and performance characterization of 1-3 piezoelectric composite air-coupled ultrasonic transducers operating at frequencies ranging from 400 kHz to 600 kHz. The transducers are fabricated using a dice-and-fill method with PZT-5 as the active material. A double-layer matching strategy is employed, utilizing hollow glass microsphere filled epoxy resin as the first matching and bonding layer. Additionally, micro-membrane filters with different pore sizes are used as the second matching layer. Thermoplastic adhesive TPU is utilized to bind the micro-membrane filter and the first matching layer. Due to the low acoustic impedance of the hollow glass microsphere filled epoxy resin and micro-membrane filter, acoustic impedance mismatch is reduced. Finite element simulation is used to determine the optimal ceramic volume fraction and ceramic pillar height of the 1-3 piezoelectric composites. When the pore size of the micro-membrane filter is 0.8 μm, the transducer achieves the lowest two-way insertion loss of -56.86 dB and the highest -6 dB bandwidth of 15.6 %, making it feasible for pulse-echo mode applications. © 2024, The Authors. All rights reserved.

关键词： Acoustic impedance

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Computing grain boundary diagrams of thermodynamic and mechanical properties

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npj Computational materials 2021年第1期7卷 1442-1453页

作者： Chongze Hu Yanwen Li Zhiyang Yu Jian Luo Department of Nanoengineering University of California San DiegoLa JollaCA 92093USA Program of Materials Science and Engineering University of California San DiegoLa JollaCA 92093USA State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou University350002 FuzhouFujianP.R.China Department of Physics Southern University of Science and TechnologyShenzhenGuangdong 518055P.R.China

Computing the grain boundary(GB)counterparts to bulk phase diagrams represents an emerging research *** a classical embrittlement model system Ga-doped Al alloy,this study demonstrates the feasibility of computing temperature-and composition-dependent GB diagrams to represent not only equilibrium thermodynamic and structural characters,but also mechanical ***,hybrid Monte Carlo and molecular dynamics(MC/MD)simulations are used to obtain the equilibrium GB structure as a function of temperature and *** GB structures are validated by aberrationcorrected scanning transmission electron ***,MD tensile tests are performed on the simulated equilibrium GB *** diagrams are computed for not only GB adsorption and structural disorder,but also interfacial structural and chemical widths,MD ultimate tensile strength,and MD tensile *** study suggests a research direction to investigate GB composition–structure–property relationships via computing GB diagrams of thermodynamic,structural,and mechanical(or potentially other)properties.

关键词： grain toughness alloy

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Quantitative Analysis of Sodium Metal Deposition and Interphase in Na Metal Batteries

arXiv

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arXiv 2023年

作者： Sayahpour, Baharak Li, Weikang Bai, Shuang Lu, Bingyu Han, Bing Chen, Yu-Ting Deysher, Grayson Parab, Saurabh Ridley, Phillip Raghavendran, Ganesh Nguyen, Long Hoang Bao Zhang, Minghao Meng, Ying Shirley Materials Science and Engineering Program University of California San DiegoCA92093 United States Department of NanoEngineering University of California San DiegoCA92093 United States Pritzker School of Molecular Engineering University of Chicago ChicagoIL60637 United States

Sodium-ion batteries exhibit significant promise as a viable alternative to current lithium-ion technologies owing to their sustainability, low cost per energy density, reliability, and safety. Despite recent advancements in cathode materials for this category of energy storage systems, the primary challenge in realizing practical applications of sodium-ion systems is the absence of an anode system with high energy density and durability. Although Na metal is the ultimate anode that can facilitate high-energy sodium-ion batteries, its use remains limited due to safety concerns and the high-capacity loss associated with the high reactivity of Na metal. In this study, titration gas chromatography is employed to accurately quantify the sodium inventory loss in ether- and carbonate-based electrolytes. Uniaxial pressure is developed as a powerful tool to control the deposition of sodium metal with dense morphology, thereby enabling high initial coulombic efficiencies. In ether-based electrolytes, the Na metal surface exhibits the presence of a uniform solid electrolyte interphase layer, primarily characterized by favorable inorganic chemical components with close-packed structures. The full cell, utilizing a controlled electroplated sodium metal in ether-based electrolyte, provides capacity retention of 91.84% after 500 cycles at 2C current rate and delivers 86 mAh/g discharge capacity at 45C current rate, suggesting the potential to enable Na metal in the next generation of sodium-ion technologies with specifications close to practical requirements. © 2023, CC BY-NC-ND.

关键词： Ethers

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Rejuvenating Mullite-Zirconia Composites from Investment-Casting Shell Waste and Investigation of Their Physicochemical and Theoretical Radiation Shielding Properties

SSRN

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SSRN 2023年

作者： Avcıoğlu, Celal Avcıoğlu, Suna Bekheet, Maged F. Artır, Recep Technische Universität Berlin Faculty III Process Sciences Institute of Material Science and Technology Fachgebiet Keramische Werkstoffe Advanced Ceramic Materials Straße des 17. Juni 135 Berlin10623 Germany Usak University Scientific Research Projects Coordinatorship Usak64000 Turkey Yıldız Technical University Faculty of Chemistry and Metallurgy Department of Metallurgical and Materials Engineering Davutpaşa Campus Istanbul34210 Turkey Marmara University Faculty of Engineering Department of Metallurgical and Materials Engineering Istanbul34722 Turkey Department of Analysis and Evaluation

The growing global production of high-precision metal products via investment casting increases the amount of ceramic shell wastes (CW) being produced. The disposal of CW causes significant environmental issues, including water and soil pollution. Although the exact chemical composition of the CW varies by the production facility, it is mainly composed of different amounts of mullite, zircon, and silica. This article assesses the feasibility of CW as a raw material in producing high-performance mullite-zirconia ceramics. In this regard, we prepared a mixture containing CW, Al2O3, and MgO and then sintered at 1500, 1550, and 1600 °C with 4h soaking time. Alumina is added to consume the free silica from CW to yield mullite, and MgO is added to obtain proper microstructure development as well as to promote zircon dissociation. The results showed that increasing sintering temperature promotes densification and enhances mechanical properties. The mullite-zirconia composite sintered at 1600 °C presented promising results, with considerable flexural and compressive strength values of 190.18 and 227.93 MPa, respectively, which are comparable to or even better than the mullite ceramics prepared from most other waste materials. Furthermore, the total atomic cross-sections, mass attenuation coefficients, linear attenuation coefficients, mean free paths, half-value layers, energy absorption buildup factors, exposure buildup factors, effective atomic numbers, effective electron densities computed using the EpiXS software, and the neutron removal cross-sections investigated using the PhyX/PSD software. Then the results were compared with the other commonly used radiation shielding materials. © 2023, The Authors. All rights reserved.

关键词： Aluminum oxide

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Effect of Heat Treatment on Improving Oer Activity of Nifeooh Based Aerogels: A Combined Experimental and Theoretical Study

SSRN

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SSRN 2024年

作者： Lakhanlal Rimon, Or Moschkowitsch, Wenjamin Elbaz, Lior Toroker, Maytal Caspary Department of Materials Science and Engineering Technion-Israel Institute of Technology Haifa3200003 Israel Bar Ilan University Ramat-Gan52900 Israel The Nancy and Stephen Grand Technion Energy Program Technion - Israel Institute of Technology Haifa3200003 Israel

Enhanced catalytic activity of oxygen evolution reaction (OER) catalysts can make water electrolysis more efficient. This study focuses on the use of a simple strategy of heat treatment to enhance the catalytic activity of NiFeOOH-based aerogels. The study shows that heat treatment of this aerogel at 150 °C leads to significant improvement in its catalytic activity, as evident in the staircase voltammetry results. To understand how heat treatment improves the catalytic activity, a DFT+U calculation was carried out on heat-treated and non-heat treated catalysts. The calculation shows that the overpotential for OER decreases with heat treatment, which is related to the relative stability of the intermediates in heat-treated and non-heat treated catalysts. Also, it has been found that heat treatment decreases work function, which might improve charge transfer and, thus, catalytic activity. Our calculations are in line with the experimental results that demonstrate the potential of controlling water content on catalytic efficiency. © 2024, The Authors. All rights reserved.

关键词： Heat treatment

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Active modulation of valley excitons in a monolayer WSe2 via chiral metamaterials

Active modulation of valley excitons in a monolayer WSe2 via...

引用

2020 Frontiers in Optics Conference, FiO 2020

作者： Wu, Zilong Zheng, Yuebing Walker Department of Mechanical Engineering Materials Science and Engineering Program Texas Materials Institute University of Texas at Austin AustinTX78712 United States

Active modulation of handedness-selective valley dynamics in a monolayer WSe2 is achieved using plasmonic moiré chiral metamaterials (MCMs) with strong and dynamically tunable optical chirality. © OSA 2020 &... 详细信息

ISBN: (纸本)9781943580804

关键词： Monolayers

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Microstructural Evolution and Stability During Strain-Controlled Fatigue in a Multiphase Microalloyed Steel

SSRN

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SSRN 2022年

作者： Shanmugam, Sankaran Madhavan, R. Suwas, Satyam Ray, R.K. Padmanabhan, K.A. Department of Metallurgical and Materials Engineering Indian Institute of Technology Madras Chennai600036 India Center for Agile and Adaptive Additive Manufacturing University of North Texas DentonTX76205 United States Department of Materials Engineering Indian Institute of Science Bangalore560012 India Indian Institute of Engineering Science and Technology Shibpur Howrah711103 India Materials Science & Engineering Program Department of Mech. Eng. Anna University Chennai600025 India

Multiphase ferrite-bainite-martensite (F-B-M) microstructure processed through rolling and two-step cooling in a V-microalloyed steel exhibited excellent stability under strain-controlled fatigue. The steel exhibited a steady state response and even cyclic hardening up to a total strain amplitude of 0.6% and displayed a cyclic softening response at total strain amplitudes > 0.7%. To understand and determine the degradation mechanisms, a detailed transmission electron microscopic investigation was carried out in fatigue tested samples as a function of total strain amplitude. At low strain amplitudes ( © 2022, The Authors. All rights reserved.

关键词： Martensite

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Periodic phase diagrams in micromagnetics with an eigenvalue solver

arXiv

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arXiv 2024年

作者： Ai, Fangzhou Lin, Zhuonan Duan, Jiawei Lomakin, Vitaliy Department of Electrical and Computer Engineering University of California La Jolla San DiegoCA92093 United States Center for Memory and Recording Research University of California La Jolla San DiegoCA92093 United States Program in Materials Science and Engineering University of California La Jolla San Diego92093 United States

This work introduces an approach to compute periodic phase diagram of micromagnetic systems by solving a periodic linearized Landau-Lifshitz-Gilbert (LLG) equation using an eigenvalue solver with the Finite Element Method formalism. The linear operator in the eigenvalue problem is defined as a function of the periodic phase shift wave vector. The dispersion diagrams are obtained by solving the eigenvalue problem for complex eigen frequencies and corresponding eigen states for a range of prescribed wave vectors. The presented approach incorporates a calculation of the periodic effective field, including the exchange and magnetostatic field components. The approach is general in that it allows handling 3D problems with any 1D, 2D, and 3D periodicities. The ability to calculated periodic diagrams provides insights into the spin wave propagation and localized resonances in complex micromagnetic structures. © 2024, CC BY-NC-ND.

关键词： Spin waves

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Effect of storage conditions on the dietary and pharmaceutical values of ginger oil, and modeling its dielectric properties

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Grasas y Aceites 2024年第4期75卷

作者： Abushal, S.A. Uguru, H. Akpomedaye, O. Kuzmin, A. Sami, R. Helal, M. Alsanei, W.A. Almehmadi, A.M. ALmasoudi, A.G. Program of Food Sciences and Nutrition Turabah University College Taif University Saudi Arabia Department of Agricultural Engineering Delta State University of Science and Technology Ozoro Nigeria Department of Electrical Engineering Delta State University of Science and Technology Ozoro Nigeria Department of Mechanization of Agricultural Products Processing National Research Mordovia State University Saransk Russia Scientific Laboratory of Advanced Composite Materials and Technologies Plekhanov Russian University of Economics Moscow Russia Department of Food Science and Nutrition College of Sciences Taif University Saudi Arabia Department of Mechanical Engineering Faculty of Engineering Taif University Saudi Arabia Department of Food and Nutrition Faculty of Human Sciences and Design King Abdulaziz University Jeddah Saudi Arabia Department of Clinical Nutrition Faculty of Applied Medical Sciences Umm Al-Qura University Makkah Saudi Arabia Program of Food Sciences and Nutrition Biology Department Branch of the College at Turbah Taif University Taif Saudi Arabia

This research was conducted to evaluate the impact of the storage conditions of ginger rhizomes on the nutritional and therapeutic properties of the ginger oil (GO). The physicochemical and phytochemical properties, fatty acid contents and dielectric constant (Ε′) of the GO were analyzed in accordance with standard guidelines. The findings revealed that the storage temperature significantly impacted the quality of GO (p ©2024 CSIC.

关键词： Polyunsaturated fatty acids

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