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arXiv 2024年

作者： Martin-Monier, Louis Pajovic, Simo Abebe, Muluneh G. Chen, Joshua Vaidya, Sachin Min, Seokhwan Choi, Seou Kooi, Steven E. Maes, Bjorn Hu, Juejun Soljačić, Marin Roques-Carmes, Charles Department of Materials Science and Engineering MIT CambridgeMA United States Department of Mechanical Engineering MIT CambridgeMA United States Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Micro- and Nanophotonic Materials Group Research Institute for Materials Science and Engineering University of Mons 20 Place du Parc MonsB-7000 Belgium Research Laboratory of Electronics MIT CambridgeMA United States Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology Daejeon34141 Korea Republic of Institute for Soldier Nanotechnologies MIT CambridgeMA United States E. L. Ginzton Laboratory Stanford University 348 Via Pueblo StanfordCA94305 United States

Scintillators are essential for converting X-ray energy into visible light in imaging technologies. Their widespread application in imaging technologies has been enabled by scalable, high-quality, and affordable manufacturing methods. Nanophotonic scintillators, which feature nanostructures at the scale of their emission wavelength, provide a promising approach to enhance emission properties like light yield, decay time, and directionality. However, scalable fabrication of such nanostructured scintillators has been a significant challenge, impeding their widespread adoption. Here, we present a scalable fabrication method for large-area nanophotonic scintillators based on the self-assembly of chalcogenide glass photonic crystals. This technique enables the production of nanophotonic scintillators over wafer-scale areas, achieving a six-fold enhancement in light yield compared to unpatterned scintillators. We demonstrate this approach using a conventional X-ray scintillator material, cerium-doped yttrium aluminum garnet (YAG:Ce). By analyzing the influence of surface nanofabrication disorder, we establish its effect on imaging performance and provide a route towards large-scale scintillation enhancements without decrease in spatial resolution. Finally, we demonstrate the practical applicability of our nanophotonic scintillators through X-ray imaging of biological and inorganic specimens. Our results indicate that this scalable fabrication technique could enable the industrial implementation of a new generation of nanophotonic-enhanced scintillators, with significant implications for advancements in medical imaging, security screening, and nondestructive testing. Copyright © 2024, The Authors. All rights reserved.

关键词： Scintillation counters

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High Cooling Rate Cells in Al-Ce Alloys: A Combined Experimental and Modelling Approach

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SSRN 2023年

作者： Baraldi, Rafael Bispo da Silva, Douglas de Gouveia, Guilherme Lisboa Garcia, Amauri Spinelli, José Eduardo Department of Materials Engineering Federal University of São Carlos UFSCar SP São Carlos13565-905 Brazil Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil Department of Manufacturing and Materials Engineering University of Campinas SP Campinas13083-860 Brazil

Microstructures are the strategic link between cast alloys processing and their properties. The investigation of α-Al morphologies is regarded as critical for broadening the potential applications of cast Al-Ce alloys. These alloys are anticipated to offer high-temperature strength. Moreover, Ce is the most abundant rare-earth element in the Earth’s crust. A central task is changing the Ce content (4.0, 6.0 and 10.1 wt.% Ce) and observing the morphologies, particularly when extremely high cooling rates - 102 to 103 K/s - are attained during cast-centrifugal Cu-mold operations. In the present contribution, rapid solidification of the Al-4wt.% Ce alloy led to generation of high cooling rate cells. A eutectic mixture of Al11Ce3 fibers and lamellae filled the intercellular spacings. Using the Hunt-Lu model, an experimental cell spacing of roughly 6.3 μm was obtained with a suitable equivalence to the modeling outcomes, corresponding to a solidification velocity of 3.1 mm/s and a cooling rate of approximately 155 K/s. © 2023, The Authors. All rights reserved.

关键词： Cells

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Evolution of 14-connected Zr₆ Secondary Building Units through Postsynthetic Linker Incorporation (Jun, 10.1021/acsami.1c07701, 2021)

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ACS APPLIED materials & INTERFACES 2021年第33期13卷 40155-40155页

作者： Hurlock, Matthew J. Hao, Leiduan Kriegsman, Kyle W. Guo, Xiaofeng O'Keeffe, Michael Zhang, Qiang Department of Chemistry Washington State University Pullman Washington 99164 United States Department of Chemistry Materials Science and Engineering Program Washington State University Pullman Washington 99164 United States School of Molecular Sciences Arizona State University Tempe Arizona 85287 United States

Two new zirconium MOFs, WSU-6 and WSU-7, were synthesized through postsynthetic modifications. In both cases, linker insertion was conducted on a MOF consisting of eight-connected (8-c) Zr6 cluster and four-connected (4-c) ETTC linker, WSU-5, which possesses the uncommon 4, 8-c scu-c topology. The insertion of 1, 4-benzenedicarboxylate into the MOF formed the new 4, 12-c mjh topology, WSU-6. Interestingly, when 2, 6-naphthalenedicarboxylate was inserted, WSU-7 can be formed, which possesses a new 4, 14-c jkz topology. WSU-7 contains very rare 14-c Zr6 secondary building units (SBUs) and is the first MOF to have a Zr6 SBUs with connectivity greater than 12. The three Zr-MOFs were structurally characterized, and the photoluminescence properties of the materials were also studied.

关键词： metal−organic frameworks postsynthetic ligand insertion new topology 14-connected Zr6 SBU luminescence

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Opto-thermoelectric microswimmers

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Light(science & Applications) 2020年第1期9卷 674-685页

作者： Xiaolei Peng Zhihan Chen Pavana Siddhartha Kollipara Yaoran Liu Jie Fang Linhan Lin Yuebing Zheng Materials Science&Engineering Program and Texas Materials Institute The University of Texas at AustinAustinTX 78712USA Walker Department of Mechanical Engineering The University of Texas at AustinAustinTX 78712USA State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084People’s Republic of China

Inspired by the“run-and-tumble”behaviours of Escherichia coli(***)cells,we develop opto-thermoelectric *** microswimmers are based on dielectric-Au Janus particles driven by a self-sustained electrical field that arises from the asymmetric optothermal response of the *** illumination by a defocused laser beam,the Janus particles exhibit an optically generated temperature gradient along the particle surfaces,leading to an opto-thermoelectrical field that propels the *** further discover that the swimming direction is determined by the particle *** enable navigation of the swimmers,we propose a new optomechanical approach to drive the in-plane rotation of Janus particles under a temperature-gradient-induced electrical field using a focused laser *** the rotation laser beam allows us to position the particles at any desired orientation and thus to actively control the swimming direction with high *** incorporating dark-field optical imaging and a feedback control algorithm,we achieve automated propelling and navigation of the *** optothermoelectric microswimmers could find applications in the study of opto-thermoelectrical coupling in dynamic colloidal systems,active matter,biomedical sensing,and targeted drug delivery.

关键词： rotation illumination beam

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Multiscale, Multimodal Characterization of Static Recrystallization in a Hot-Compressed Mg-3.2zn-0.1ca Wt.% Alloy

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SSRN 2023年

作者： Lee, Sangwon Berman, Tracy D. Yildirim, Can Detlefs, Carsten Allison, John E. Bucsek, Ashley Department of Mechanical Engineering University of Michigan Ann ArborMI United States Department of Materials Science and Engineering University of Michigan Ann ArborMI United States European Synchrotron Radiation Facility GrenobleCedex 9 France

We present a multiscale study on the recovery and recrystallization of an 80% hot-compressed Mg-3.2Zn-0.1Ca wt.% (ZX30) alloy using high-resolution X-ray diffraction (HR-XRD) statistical analysis and dark field X-ray microscopy (DFXM). Using HR-XRD statistical analysis, we track more than 8,000 sub-surface grains during the recovery and recrystallization processes during in-situ annealing. For each grain, the grain-specific change in relative volume is measured as a function of annealing time. The results show that the initial grain volume plays an important role in determining which grains from the as-deformed condition are likely to survive the annealing process (as opposed to being consumed by recrystallization). Finally, at several points during the annealing process, we "zoom in" to two individual grains using DFXM: one that is newly recrystallized and one that is pre-existing, i.e., exists from the as-deformed state. The results show small intragranular variations in elastic lattice strain and misorientation with a spatial resolution of ~100 nm. This combination of HR-XRD and DFXM enables multiscale, multimodal in-situ characterization that is particularly useful for small and/or highly deformed grains that are often difficult to resolve using more standard diffraction microstructure imaging techniques. © 2023, The Authors. All rights reserved.

关键词： Recovery

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Strongly Hybridized Phonons in One-Dimensional van der Waals Crystals

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Physical Review Letters 2025年第17期134卷 176101-176101页

作者： Shaoqi Sun Qingyun Lin Yihuan Li Daichi Kozawa Huizhen Wu Shigeo Maruyama Pilkyung Moon Toshikaze Kariyado Ryo Kitaura Sihan Zhao School of Physics Zhejiang Key Laboratory of Micro-Nano Quantum Chips and Quantum Control and State Key Laboratory of Silicon and Advanced Semiconductor Materials Zhejiang University Hangzhou 310058 China Center of Electron Microscopy School of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Research Center for Materials Nanoarchitectonics (MANA) National Institute for Materials Science (NIMS) 1-1 Namiki Tsukuba 305-0044 Japan Department of Mechanical Engineering The University of Tokyo Tokyo 113-8656 Japan Arts and Sciences NYU Shanghai Shanghai 200124 China NYU-ECNU Institute of Physics at NYU Shanghai Shanghai 200062 China

The phenomena of pronounced electron-electron and electron-phonon interactions in one-dimensional (1D) systems are ubiquitous, which are well described by frameworks of Luttinger liquid, Peierls instability, and concomitant charge density wave. However, the experimental observation of strongly hybridized phonons in 1D was not demonstrated. Herein we report the first observation of strongly hybridized phonons in 1D condensed matters by using double-walled carbon nanotubes (DWNTs), representative 1D van der Waals crystals, by combining the spectroscopic and microscopic tools as well as the ab initio density functional theory (DFT) calculations. We observe uncharted phonon modes in one commensurate and three incommensurate DWNT crystals, three of which concurrently exhibit strongly reconstructed electronic band structures. Our DFT calculations for the experimentally observed commensurate DWNT (7, 7) @ (12, 12) reveal that this new phonon mode originates from a (nearly) degenerate coupling between two transverse acoustic modes (ZA modes) of constituent inner and outer nanotubes having approximately trigonal and pentagonal rotational symmetry along the nanotube circumferences. Such coupling strongly hybridizes the two phonon modes in different shells and leads to the formation of a unique lattice motion featuring evenly distributed vibrational amplitudes over inner and outer nanotubes, distinct from any known phonon modes in 1D systems. All four DWNTs that exhibit the pronounced new phonon modes show small chiral angle twists, closely matched diameter ratios of 35 and decreased frequencies of new phonon modes with increased diameters, all supporting the uncovered coupling mechanism. Our discovery of strongly hybridized phonons in DWNTs opens new opportunities for engineering phonons and exploring novel phonon-related phenomena in 1D condensed matters.

关键词： Van der Waals forces

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Development of Linear Battery Model for Path Planning with Mixed Integer Linear programming: Simulated and Experimental Validation

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IFAC-PapersOnLine 2023年第3期56卷 7-12页

作者： Drew D. Scott Isaac E. Weintraub Satyanarayana G. Manyam David W. Casbeer Manish Kumar Michael J. Rothenberger Department of Mechanical and Materials Engineering University of Cincinnati Electronics Engineer Control Science Center Air Force Research Laboratory WPAFB OH 45433 Research Scientist Infoscitex corp. a DCS company Dayton OH 45431 Technical Area Lead Cooperative & Intelligent Control Control Science Center Air Force Research Laboratory WPAFB OH 45433 Professor in Department of Mechanical and Materials Engineering University of Cincinnati Mechanical Engineer Flight Systems Integration Branch Air Force Research Laboratory WPAFB OH 45433

Mixed Integer Linear programs (MILPs) are often used in the path planning of both ground and aerial vehicles. Such a formulation of the path planning problem requires a linear objective function and constraints, limiting the fidelity of the tracking of vehicle states. One such state often used is the charge level of the on board battery. High-fidelity battery state estimation requires nonlinear differential equations to be solved. This state estimation is vital in path planning to ensure flyable paths, however when using a linear path planning problem cannot implement these nonlinear models. Poor accuracy in battery estimation during the path planning runs the risk of the planned path being feasible by the estimation model but in reality will deplete the battery to a critical level, resulting in a dangerous planned path. To the end of higher accuracy battery estimation within a linear framework, we test a simple linear battery model which predicts the change in state-of-charge (SOC) of a battery given a power draw, time duration, and current SOC in the context of an a-priori path planning problem. This context differentiates itself from real-time estimation. In ahead-of-time path planning, the changes to battery draw are often assumed as a series of constant power draws as opposed to rapidly changing power draw which may occur in real-time battery tracking and estimation. The linear battery model is presented and then tested against alternate models in both numerical and in experimental tests. Further, the effect of the proposed linear model on the time-to-solve a resource constrained shortest path problem is also evaluated, where two different algorithms are used to solve the path planning problem. It is seen that the linear model performs well in battery state estimation while remaining implementable in a Linear program or MILP, with minimal effect on the time-to-solve. This provides what we consider to be a worthwhile trade-off in improved accuracy relative to in

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Coupled Creep and Enviroment-Induced Damage of Aluminum Alloy 2219: A Study

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SSRN 2024年

作者： Sun, Jingjue Zhang, Wei Lv, Shengli Srivatsan, T.S. College of Aeronautics Northwestern Polytechnical University Xi’an710072 China Innovation Group of Marine Engineering Materials and Corrosion Control Southern Marine Science and Engineering Guangdong Laboratory Zhuhai519080 China Department of Mechanical Engineering The University of Akron AkronOH44325 United States Northwestern Polytechnical University China

Aluminum alloys have over the years grown both in stature and strength so as to be a prime of ‘preferred’ candidate for use in a spectrum of applications in the industries spanning aerospace and automotive. However, the aluminum alloys are often susceptible to failure due to creep during use. This then did necessitate the need for a careful, cautious and complete study of their safety and durability. At present, research into understanding the creep behavior of aluminum alloys is focused on high-temperatures with little attention being given to creep upon exposure to aggressive aqueous environments. In this study, aluminum alloy 2219 was subjected to uniaxial tensile creep tests very much in accordance with the creep test standard for the purpose of investigating the room temperature creep behavior of the alloy under constant load and at room temperature. Based on the Norton-Bailey creep model, the relevant parameters in the room temperature creep constitutive model of aluminum alloy 2219 were determined. The creep was coupled with environment-induced damage and a corresponding creep – environment induced damage model was first established and then simulated to predict the creep behavior of aluminum alloy structures in actual service environments, thereby enabling in providing a basis for the life prediction of aerospace structures made from an aluminum alloy. © 2024, The Authors. All rights reserved.

关键词： Aluminum alloys

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Correlation versus dissipation in a non-Hermitian Anderson impurity model

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Physical Review B 2025年第12期111卷 125157-125157页

作者： Kazuki Yamamoto Masaya Nakagawa Norio Kawakami Department of Physics Tokyo Institute of Technology Meguro Tokyo 152-8551 Japan Department of Physics University of Tokyo Hongo Tokyo 113-0033 Japan Fundamental Quantum Science Program TRIP Headquarters RIKEN Wako 351-0198 Japan Department of Physics Ritsumeikan University Kusatsu Shiga 525-8577 Japan Department of Materials Engineering Science Osaka University Toyonaka Osaka 560-8531 Japan

We analyze the competition between strong correlations and dissipation in quantum impurity systems from the Kondo regime to the valence fluctuation regime by developing a slave-boson theory for a non-Hermitian Anderson impurity model with one-body loss. Notably, in the non-Hermitian Kondo regime, strong correlations qualitatively change the nature of dissipation through renormalization effects, where the effective one-body loss is suppressed and emergent many-body dissipation characterized by the complex-valued hybridization is generated. We unveil the mechanism of a dissipative quantum phase transition of the Kondo state on the basis of this renormalization effect, which counterintuitively enhances the lifetime of the impurity against loss. We also find a crossover from the non-Hermitian Kondo regime to the valence fluctuation regime dominated by one-body dissipation. Our results can be tested in a wide variety of setups such as quantum dots coupled to electronic leads and quantum point contacts in ultracold Fermi gases.

关键词： Bosons

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A review and a statistical analysis of porosity in metals additively manufactured by laser powder bed fusion

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Opto-Electronic Advances 2022年第10期5卷 35-68页

作者： Dawei Wang Huili Han Bo Sa Kelin Li Jujie Yan Jiazhen Zhang Jianguang Liu Zhengdi He Ning Wang Ming Yan Department of Materials Science and Engineering and Shenzhen Key Laboratory for Additive Manufacturing of High Performance MaterialsSouthern University of Science and TechnologyShenzhen 518055China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China COMAC Beijing Aircraft Technology Research Institute Beijing 102211China Shenzhen Technology University Shenzhen 518118China Jiaxing Research Institute Southern University of Science and TechnologyJiaxing 314031China

Additive manufacturing(AM), or 3D printing, is an emerging technology that “adds” materials up and constructs products through a layer-by-layer procedure. Laser powder bed fusion(LPBF) is a powder-bed-based AM technology that can fabricate a large variety of metallic materials with excellent quality and accuracy. However, various defects such as porosity,cracks, and incursions can be generated during the printing process. As the most universal and a near-inevitable defect,porosity plays a substantial role in determining the mechanical performance of as-printed products. This work presents a comprehensive review of literatures that focused on the porosity in LPBF printed metals. The formation mechanisms,evaluation methods, effects on mechanical performance with corresponding models, and controlling methods of porosity have been illustrated and discussed in-depth. Achievements in four representative metals, namely Ti-6Al-4V, 316L, Inconel 718, and Al Si10Mg, have been critically reviewed with a statistical analysis on the correlation between porosity fraction and tensile properties. Ductility has been determined as the most sensitive property to porosity among several key tensile properties. This review also provides potential directions and opportunities to address the current porosity-related challenges.

关键词： additive manufacturing laser powder bed fusion selective laser melting porosity defects mechanical performance metallic materials perspectives

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