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2020 IEEE Nuclear science Symposium and Medical Imaging Conference, NSS/MIC 2020

作者： Woldegiorgis, Surafel Nimmagadda, Jyothier Baciak, James The Nuclear Engineering Program The Department of Materials Science and Engineering The University of Florida GainesvilleFL32603 United States

ISBN: (纸本)9781728176932

The energy spectrum and spatial distribution of the neutron beam from a reactor is an essential component of designing experimentations utilizing the reactor as a radiation source. Obtaining such information requires the use of detailed MCNP model of the reactor and experimental validation procedures. After updating the MCNP model of the University of Florida Training Reactor (UFTR) to align it with the current core arrangement that uses low enriched uranium (LEU), both the radial neutron flux toward the beam ports and the energy spectrum at the reactor core were generated using the model. This was followed by experimental validations based on neutron activation analysis (NAA) by irradiating multiple activation foils. A constant ratio between MCNP and measured neutron flux values was obtained at multiple locations along the reactor's beam ports, showing that the model captures the spatial distribution of neutron flux profiles without a significant systematic error. The energy spectrum at the core was extracted using the Unfolding with MAXED and GRAVEL (UMG) software. The spectrum unfolded by both MAXED and GRAVEL algorithms display features expected in thermal reactor neutron energy distribution, i.e., thermal, fast or fission, and intermediate or slowing down regions. The thermal and epithermal neutron fluxes at the reactor core calculated from the spectrum unfolded by the MAXED n algorithm are 1. 56 ± 0. 12 × 1012 cm2s and 1. 98 ± 0. 01 × 1012 n sm2s, whereas the corresponding values calculated from the spectrum unfolded by the GRAVEL algorithm are 1. 50 ± 0. 12 × n 1012 n and 3. 74 ± 0. 21 × 1012. Following the cm2s cm2s experimental validation, the full geometry MCNP model of the reactor has been utilized for a neutron tomography research project and it will continue to benefit future projects using the reactor facility. © 2020 IEEE

关键词： Neutron flux

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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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Digital Twin and Digital Game-Based Training in Integrated Photonics and Semiconductor Resource-Efficiency

Digital Twin and Digital Game-Based Training in Integrated P...

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Education and Training in Optics and Photonics (ETOP), IEEE Conference on

作者： S. Saini I. Fay T. Morrisey J. Krambeck A. Gupta M. Hall A. Agarwal P. O’Brien E.A. Unger G. Norris R. Kirchain L.C. Kimerling IKIM Initiative Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge Comparative Media Studies Program Massachusetts Institute of Technology Cambridge USA Materials Research Laboratory Massachusetts Institute of Technology Cambridge USA Lee Maltings Dyke Parade Tyndall National Institute Cork Ireland SHINE Enterprise Massachusetts Institute of Technology Cambridge USA

ISBN: (数字)9798331543013

ISBN: (纸本)9798331543020

As Co-Packaged Optics drives advanced packaging solutions for data centers, AI computing, and sensing/imaging systems, digital twins and digital games offer just-in-time training support for rapid reskill/upskill of engineers and technicians. Recent advances in digital twins of select packaging tools for CPO (fiber-attach, die saw, die bonder) will be presented with early results on learner experience within a bootcamp based setting. In addition, learner results will be presented for a digital game that trains in Life Cycle Thinking for resource-efficient manufacturing. This new photonics education frontier expands CPO curricula to emphasize broad training in the resource flows of the semiconductor manufacturing supply chain, to assess enabling integrated photonics solutions for systems, and in fabrication or packaging.

关键词： Training Dies Supply chains Games Tutorials Packaging Optics Digital twins Standards Photonics

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Efficient Predictions of Formation Energies and Convex Hulls from Density Functional Tight Binding Calculations

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SSRN 2022年

作者： Kumar, Anshuman Ali, Zulfikhar A. Wong, Bryan M. Materials Science & Engineering Program University of California Riverside RiversideCA92521 United States Department of Physics & Astronomy University of California Riverside RiversideCA92521 United States Materials Science & Engineering Program Department of Chemical & Environmental Engineering Department of Physics & Astronomy Department of Chemistry University of California Riverside RiversideCA92521 United States

Defects in materials significantly alter their electronic and structural properties, which affect the performance of electronic devices, structural alloys, and functional materials. However, calculating all the possible defects in complex materials with conventional Density Functional Theory (DFT) can be computationally prohibitive. To enhance the efficiency of these calculations, we interfaced Density Functional Tight Binding (DFTB) with the Clusters Approach to Statistical Mechanics (CASM) software package for the first time to calculate formation energies and convex hulls. Using SiC and ZnO as representative examples, we show that DFTB gives accurate results and can be a computationally cheaper alternative to DFT. Our DFTB+CASM implementation allows for an efficient exploration (up to an order of magnitude faster than DFT) of formation energies and convex hulls, which researchers can use to probe other complex systems. © 2022, The Authors. All rights reserved.

关键词： Density functional theory

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Piezo-Flexocatalysis of Single-Atom Pt-Loaded Graphitic Carbon Nitride

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Small Methods 2024年第7期8卷 e2301287页

作者： Wang, Yu Teng Lin, Hsun-Yen Chen, Yu-Ching Lin, Yan-Gu Wu, Jyh Ming Department of Materials Science and Engineering National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan Program in Prospective Functional Materials Industry National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan National Synchrotron Radiation Research Center 101 Hsin-Ann Road Hsinchu Science Park Hsinchu300092 Taiwan High Entropy Materials Center National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan

This study develops a single-atom Pt-loaded graphitic carbon nitride (SA-Pt/CN) and evaluates its piezo-flexocatalytic properties by conducting a hydrogen evolution reaction (HER) and Rhodamine B (RB) dye degradation test under ultrasonic vibration in the dark. SA-Pt/CN has a hydrogen gas yield of 1283.8 µmol g−1 h−1, which is 23.3 times higher than that of pristine g-C3N4. Moreover, SA-Pt/CN enhances the dye degradation reaction rate by ≈2.3 times compared with the pristine sample. SA-Pt/CN exhibits lattice distortion and strain gradient enlargement caused by the single atom Pt at the N sites of g-C3N4, which disrupts the symmetric structure and contributes to the enhancement of piezoelectric and flexoelectric polarization. As far as it is known, this is the first study to investigate the piezo-flexocatalytic reaction of SA-Pt/CN without light irradiation and provides new insights into single-atom piezocatalysts. © 2023 Wiley-VCH GmbH.

关键词： Degradation

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No external load measurement strategy for micro thermoelectric generator based on high-performance Si_(1-x-y)Ge_(x)Sn_(y) film

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Journal of Materiomics 2021年第4期7卷 665-671页

作者： Ying Peng Sijing Zhu Huajun Lai Jie Gao Masashi Kurosawa Osamu Nakatsuka Sakae Tanemura Biaolin Peng Lei Miao Guangxi Key Laboratory of Information Material School of Material Science and EngineeringGuilin University of Electronic TechnologyGuilin541004China Department of Materials Physics Graduate School of EngineeringNagoya UniversityNagoya464-8603Japan PRESTO Japan Science and Technology Agency4-1-8HonchoKawaguchiSaitama332-0012Japan Institute of Materials and Systems for Sustainability Nagoya UniversityNagoya464-8601Japan Japan Fine Ceramics Center 2-4-1 MutsunoAtsuta-kuNagoya456-8587Japan Center on Nanoenergy Research Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured MaterialsGuangxi Key Laboratory for Relativity AstrophysicsNanning530004China Department of Materials Science and Engineering SIT Research LaboratoriesInnovative Global ProgramFaculty of EngineeringShibaura Institute of TechnologyTokyo135-8548Japan

In this study,a micro in-plane p-type thermoelectric generator(TEG),which consists of thin-film Si_(1-x-y)Ge_(x)Sn_(y) ternary alloy semiconductor on insulator,is developed to make efficient use of waste heat such as human body.A power factor value as high as 1095 mWm^(-1) K^(-2) had been achieved using Bion implanted and short-term rapid thermal annealing(RTA)*** addition,a measuring scheme for micro TEG without external load resistance was *** one measuring session,multiple parameters can be *** micro single-arm TEG prepared by semiconductor process can output 0.29 nW power at a temperature difference of 15 K,and a cross-sectional power density has reached up to 0.58 mW/cm^(2),which is a superior value for wearable *** findings of this study have important reference value for wearable device performance improvement and output power measuring of micro TEG.

关键词： Si_(1-x-y)Ge_(x)Sn_(y) film P-type TEG No external load measurement Ambient power density

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Phase Equilibria and Thermodynamics Assessment of the Co-Fe-Nb Ternary System

SSRN

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SSRN 2023年

作者： Hutabalian, Yohanes Hermana, Gita Novian Laksono, Andromeda Dwi Chen, Sinn-Wen Department of Chemical Engineering National Tsing Hua University Hsinchu30013 Taiwan Research and Development Center PT. Gotion Indonesia Materials Jakarta12950 Indonesia Department of Advanced Materials Engineering Bandung Polytechnic for Manufacturing West Java Bandung40135 Indonesia Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei10672 Taiwan Study Program of Materials and Metallurgical Engineering Institut Teknologi Kalimantan Soekarno-Hatta Street Km. 15 Karang Joang Balikpapan East Kalimantan76127 Indonesia High Entropy Materials Center National Tsing Hua University Hsinchu30013 Taiwan

The Co-Fe-Nb materials system is a crucial material for magnetic applications. Despite its importance, the phase equilibria and thermodynamic characteristics of this ternary system have not been explored in detail. This study employs the Calphad method to model the phase equilibria of the Co-Fe-Nb ternary system. To obtain the ternary interaction parameters, the experimental data on the isothermal sections at temperatures ranging from 700°C to 1300°C was evaluated. These findings indicate that the Co-Fe-Nb system contains no ternary compound, and the (Co,Fe)7Nb6 phase exists as a single solid solution. Significant solubility of the third element in the binary compounds of Co2Nb (laves C14) and Fe2Nb (laves C15) is also observed. The results are in good agreement with the experimental data. Furthermore, a liquidus projection of the system is presented, for the first time, revealing seven primary solidification phases in the Co-Fe-Nb ternary system. © 2023, The Authors. All rights reserved.

关键词： Ternary systems

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

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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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Phonon dynamics and magnetodielectric relaxation in distorted honeycomb ferrimagnet Ni4Nb2O9: Experiment and first-principles study

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Physical Review materials 2025年第4期9卷 045202-045202页

作者： Harshita Singh Sobhit Singh Sayandeep Ghosh Prativa Pramanik Vasant Sathe Roland Mathieu Wilfrid Prellier Subhash Thota Department of Physics Indian Institute of Technology Guwahati Assam 781039 India Department of Mechanical Engineering University of Rochester Rochester New York 14627 USA Materials Science Program University of Rochester Rochester New York 14627 USA Department of Physics Chungnam National University Daejeon 34134 Republic of Korea Department of Physics Kunsan National University Gunsan 54150 Republic of Korea Department of Materials Science and Engineering Uppsala University Uppsala SE-75103 Sweden UGC DAE Consortium for Scientific Research Indore 452 001 India Laboratoire CRISMAT ENSICAEN CNRS Université de Caen Normandie Université Caen France

We present the experimental and theoretical studies of lattice dynamics, electronic structure, and magnetodielectric relaxation in the ferrimagnetic (FiM) Ni4Nb2O9. This system exhibits a distorted honeycomb lattice with the space group Pbcn (no. 60) and undergoes FiM ordering below 76 K (TFN), accompanied by a magnetic compensation at 33 K (TCOM). By employing density-functional theory (DFT+U) calculations and vibrational spectroscopy, we study all the allowed Raman and infrared phonon modes in Ni4Nb2O9. Temperature-dependent analysis of Raman-active phonon frequencies provides evidence of spin-phonon coupling in Ni4Nb2O9. Interestingly, we observe a nonlinear mode softening phenomenon in both frequencies ω(T) and their linewidths δωF(T), which can be described using three-phonon anharmonic processes. Contrary to the behavior of the remaining modes, 510 cm−1 mode shows a blue shift and effectively acts as a breathing mode for Ni atoms of two sublattices, and hence plays a crucial role in stabilizing the FiM ground state, thus explaining the strong sensitivity of this Ag mode to temperature. Our investigation of the temperature- and field-dependent relative dielectric permittivity and loss-tangent data reveals the absence of magnetodielectric coupling and the presence of dipole relaxation behavior in Ni4Nb2O9. Additionally, the theoretically determined indirect band gap is about 2.7 eV. Overall, our study helps to fill the existing knowledge gap and provides valuable insights into the electronic, vibrational, and magnetodielectric properties of Ni4Nb2O9, shedding light on its potential applications in dielectric-ceramic resonators and electrochemical sensors.

关键词： Local density approximation

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Large negative magnetoresistance in the off-stoichiometric topological semimetal PrSbxTe2−x

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Physical Review B 2025年第2期111卷 024421-024421页

作者： Gokul Acharya Krishna Pandey M. M. Sharma Jian Wang Santosh Karki Chhetri Md Rafique Un Nabi Dinesh Upreti Rabindra Basnet Josh Sakon Department of Physics University of Arkansas Fayetteville Arkansas 72701 USA Materials Science and Engineering Program Institute for Nanoscience and Engineering University of Arkansas Fayetteville Arkansas 72701 USA Department of Chemistry and Biochemistry Wichita State University Wichita Kansas 67260 USA Department of Chemistry & Physics University of Arkansas at Pine Bluff Pine Bluff Arkansas 71603 USA Department of Chemistry and Biochemistry University of Arkansas Fayetteville Arkansas 72701 USA

Magnetic topological materials LnSbTe (Ln = lanthanide) have attracted intensive attention because of the presence of interplay between magnetism, topological, and electron correlations depending on the choices of magnetic Ln elements. Varying Sb and Te composition is an efficient approach to control structural, magnetic, and electronic properties. Here, we report on the composition-dependent properties in PrSbxTe2−x. We identified the tetragonal-to-orthorhombic structure transitions in this material system and very large negative magnetoresistance in the x=0.3 composition, which might be ascribed to the coupling between magnetism and transport. Such unusual magnetotransport enables PrSbxTe2−x topological materials as a promising platform for device applications.

关键词： Magnetoresistance

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