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arXiv 2024年

作者： McDevitt, Christopher J. Tang, Xian-Zhu Nuclear Engineering Program Department of Materials Science and Engineering University of Florida GainesvilleFL32611 United States Theoretical Division Los Alamos National Laboratory Los Alamos NM87545 United States

A physics-informed neural network (PINN) is used to evaluate the fast ion distribution in the hot spot of an inertial confinement fusion target. The use of tailored input and output layers to the neural network is shown to enable a PINN to learn the parametric solution to the Vlasov-Fokker-Planck equation in the absence of any synthetic or experimental data. As an explicit demonstration of the approach, the specific problem of Knudsen layer fusion yield reduction is treated. Here, predictions from the Vlasov-Fokker-Planck PINN are used to provide a non-perturbative solution of the fast ion tail in the vicinity of the hot spot thus allowing the spatial profile of the fusion reactivity to be evaluated for a range of collisionalities and hot spot conditions. Excellent agreement is found between the predictions of the Vlasov-Fokker-Planck PINN and results from traditional numerical solvers with respect to both the energy and spatial distribution of fast ions and the fusion reactivity profile demonstrating that the Vlasov-Fokker-Planck PINN provides an accurate and efficient means of determining the impact of Knudsen layer yield reduction across a broad range of plasma conditions. © 2024, CC BY.

关键词： Deep learning

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Lost-Core Injection Molding of Fluidic Elastomer Actuators for the Fabrication of a Modular Eel-Inspired Soft Robot

Lost-Core Injection Molding of Fluidic Elastomer Actuators f...

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IEEE International Conference on Soft Robotics (RoboSoft)

作者： Jacobo Cervera-Torralba Yuxiang Kang Eesa M. Khan Iman Adibnazari Michael T. Tolley Department of Mechanical and Aerospace Engineering University of California San Diego (UCSD) La Jolla CA USA Materials Science and Engineering Program University of California San Diego (UCSD) La Jolla CA USA

Biologically inspired soft anguilliform swimming robots show great promise in underwater exploration. Their soft bodies promise to reduce the chance of harming humans or wildlife with which they come into contact, and also to reduce their chance of becoming stuck in complex environments. Furthermore, the efficiency of anguilliform swimming may enable long duration operation. However, the design and fabrication of soft anguilliform swimming robots remain challenging. Here we present a design concept for a modular soft anguilliform robot. To address the challenge of consistently fabricating modules for this design, we also present a new fabrication method that combines injection molding and lost-core molding for the consistent fabrication of bi-directional fluidic elastomer actuator modules. We evaluate the consistency of the fabrication method through visual inspection, weight measurements, bending angle measurements and the measurement of force output of the actuator. This work represents a step towards an autonomous eel-inspired soft robot, as well as a new fabrication approach that may enable a number of other new soft robotic systems.

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Correlation between Composition and Work Function Through Kelvin Probe Force Microscopy – Pure Magnesium Single Crystals

SSRN

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SSRN 2023年

作者： Türe, Yiğit Kaya, Ali Arslan Shin, Kwang Seon Turan, Servet Eskisehir Technical University Porsuk Vocational School Electronics and Automation Department Program of Mechatronics Eskisehir Turkey Mugla Sıtkı Kocman University Engineering Faculty Metallurgy and Materials Engineering Department Mugla Turkey Seoul National University Materials Science and Engineering Department Seoul Korea Republic of Eskisehir Technical University Engineering Faculty Materials Science and Engineering Department Eskisehir Turkey

The aim of this work was to investigate the feasibility of observing the effect of impurities in pure magnesium (Mg) on the work function (WF) measurements by using Kelvin Probe Force Microscopy (KPFM). In essence, the pure Mg samples used in this study can be regarded as extremely dilute solid solutions of Mg with some impurity atoms. This investigation further considers the measured WF differences within a crystal as figures that are directly affected by the free electron density distribution, which essentially refers to the nature of the interatomic bonding. A corollary of this view is that stacking fault energy (SFE) changes in a solid solution system can also be revealed via KPFM measurements, as SFE also depends on the free electron density distribution. Since the atomic density would affect the WF and SFE levels, the crystal orientations of the single crystal Mg samples had to be determined via electron diffraction patterns obtained via TEM. It has been shown that WF differences as measured via KPFM, offer a technique that can be at least qualitatively correlated with the interatomic bond strength levels, and therefore be also interpreted as an indicator of SFE levels. This practical measurement approach appears to be a reliable way of understanding the effect of individual elemental changes in multi-element solid-solution systems which currently do not lend themselves to computational techniques due to the number of elements involved. It should be borne in mind that the computed SFE values in the literature are not treated as absolute values but rather become useful when assessing the properties of alloys at a fundamental level, i.e., free electron density distributions. Therefore, it seems possible to use the principles of ‘electronic metallurgy’ in developing multi-element alloy systems. © 2023, The Authors. All rights reserved.

关键词： Single crystals

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Flexible organic solar cells for biomedical devices

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Nano Research 2021年第9期14卷 2891-2903页

作者： Bin Kan Faheem Ershad Zhoulyu Rao Cunjiang Yu Department of Mechanical Engineering University of HoustonHoustonTX 77204USA Department of Biomedical Engineering University of HoustonHoustonTX 77204USA Materials Science and Engineering Program University of HoustonHoustonTX 77204USA Department of Electrical and Computer Engineering University of HoustonHoustonTX 77204USA Texas Center for Superconductivity University of HoustonHoustonTX 77204USA

Organic solar cells(OSCs),particularly made based on solution processing methods,have made significant progress over the past decades through the concurrent evolution of organic photovoltaic materials and device ***,high power conversion efficiencies around 18%and over 16%have been demonstrated in both rigid and flexible OSCs,*** most of the OSC research has centered on efficiency and cost,their emerging and potential usages in many critical applications,particularly in biomedical fields have been *** this mini-review,we will briefly discuss the high-performance organic photovoltaic materials and the representative flexible OSCs to give a scope on the recent rapid development of ***,we will review some progress on the applications of OSCs in biomedical devices and integrated *** potential challenges associated with integrating OSCs for biomedical devices will be put forward.

关键词： organic solar cells photovoltaic flexible biomedical bioelectronics

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Epitaxial Growth and Characterization of Copper Gallate (CuGa2O4) Thin Films by Pulsed Laser Deposition

SSRN

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SSRN 2024年

作者： Emu, Injamamul Hoque Samuels, Brian C. Karmakar, Subrata Hamid, Md. Abdul Shiam, Istiaq Firoz Sarkar, Pallab Kumar Tasnim, Ayesha Haque, Ariful Droopad, Ravi Ingram School of Engineering Texas State University San MarcosTX78666 United States Materials Science Engineering & Commercialization Program Texas State University San MarcosTX78666 United States

High-quality crystalline copper gallate (CuGa2O4) thin films were grown on c-plane sapphire substrates using the pulsed laser deposition (PLD) technique by optimizing the growth parameters (i.e., temperature, oxygen chamber pressure, and laser energy density). The obtained XRD patterns validated that the preferred orientation of the crystalline CuGa2O4 thin film is along the [111] direction, and the crystallinity of the films improved with increasing substrate temperature while maintaining a constant O2 pressure, as assessed by measuring the full width at half maximum (FWHM) of the prominent (222) plane. Reducing the oxygen pressure leads to the emergence of β-Ga2O3 peaks rather than the CuGa2O4 peaks due to the incomplete oxidation of copper (Cu). Subsequent XRD phi (φ) scans revealed a sixfold rotational symmetry of CuGa2O4 and a 30º epitaxial relationship between the film and the sapphire substrate. X-ray photoelectron spectroscopy (XPS) spectra confirmed the presence of Cu1+, Cu2+, and Ga3+ oxidation states in the films. Increasing laser energy density resulted in the complete oxidation of Cu and an increase in the film thickness from 51.8 nm to 183.4 nm. The direct bandgap of CuGa2O4 films was determined to be approximately 4.51±0.01 eV by analyzing the UV-Vis absorbance spectra using the Tauc equation. The refractive index was found to be approximately 2.05±0.01 based on the spectroscopic ellipsometry data. While the impact of increasing laser energy density was negligible on the parameters such as crystal structure, rotational symmetry, oxidation states of gallium (Ga), oxygen (O), bandgap, and refractive index of CuGa2O4 thin film, notable alterations in the oxidation state of Cu and film thickness were observed. © 2024, The Authors. All rights reserved.

关键词： Thin films

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Complex RNA-DNA hybrid nanoshapes from iterative mix-andmatch screening

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Nano Research 2021年第1期14卷 46-51页

作者： Shi Chen Zhiyuan Zhang Eugene Alforque Thomas Hermann Department of Chemistry and Biochemistry University of CaliforniaSan DiegoCA 92093USA Center for Drug Discovery Innovation University of CaliforniaSan DiegoCA 92093USA Materials Science and Engineering Program University of CaliforniaSan DiegoCA 92093USA

Hybrid nucleic acid nanostructures partition architectural and functional roles between ribonucleic acid(RNA)joints and deoxyribonucleic acid(DNA)*** self-assemble from nucleic acid modules through synergistic stabilization of marginally stable base pairing interactions within circularly closed ***,we report the development of hybrid nanoshapes that include multiple different RNA modules such as internal loop and three-way junction(3WJ)*** iterative mix-and-match screening approach was used to identify suitable DNA connectors that furnished stable nanoshapes for combinations of different RNA *** resulting complex multicomponent RNA-DNA hybrid nanoshapes were characterized by atomic force microscopy(AFM)*** research provides proof of concept for modular design,assembly and screening of RNA-DNA hybrid nanoshapes as building blocks for complex extended nucleic acid materials with features at the sub-10 nm scale.

关键词： nucleic acid nanotechnology nanoshapes ribonucleic acid(RNA)three-way junction(3WJ) RNA deoxyribonucleic acid(DNA) sub-10 nm features

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Local step-flow dynamics in thin film growth with desorption

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Physical Review materials 2024年第3期8卷 033403-033403页

作者： Xiaozhi Zhang Jeffrey G. Ulbrandt Peco Myint Andrei Fluerasu Lutz Wiegart Yugang Zhang Christie Nelson Karl F. Ludwig Randall L. Headrick Department of Physics and Materials Science Program University of Vermont Burlington Vermont 05405 USA Division of Materials Science and Engineering Boston University Boston Massachusetts 02215 USA X-ray Science Division Argonne National Laboratory Lemont Illinois 60439 USA National Synchrotron Light Source II Brookhaven National Lab Upton New York 11973 USA Department of Physics Boston University Boston Massachusetts 02215 USA

Desorption of deposited species plays a role in determining the evolution of surface morphology during crystal growth when the desorption time constant is short compared with the time to diffuse to a defect site, step edge, or kink. However, experiments to directly test the predictions of these effects are lacking. Novel techniques such as in situ coherent x-ray scattering can provide significant new information. Herein we present x-ray photon correlation spectroscopy (XPCS) measurements during diindenoperylene (DIP) vapor deposition on thermally oxidized silicon surfaces. DIP forms a nearly complete two-dimensional first layer over the range of temperatures studied (40–120∘C), followed by mounded growth during subsequent deposition. Local step flow within mounds was observed, and we find that there was a terrace-length-dependent behavior of the step edge dynamics. This led to unstable growth with rapid roughening (β>0.5) and deviation from a symmetric error-function-like height profile. At high temperatures, the grooves between the mounds tend to close up leading to nearly flat polycrystalline films. Numerical analysis based on a (1+1)-dimensional model suggests that terrace-length dependent desorption of deposited ad-molecules is an essential cause of the step dynamics, and it influences the morphology evolution.

关键词： Growth Surface diffusion Surface instabilities Atomic force microscopy Surface scattering X-ray techniques

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Inclusive STEAM education in diverse disciplines of sustainable energy and AI

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Energy and AI 2022年第1期7卷 43-47页

作者： Michelle Skowronek Renée M.Gilberti Michael Petro Christopher Sancomb Stacy Maddern Jasna Jankovic Urban and Community Studies University of ConnecticutStorrsUnited States McNair Scholars Program Center for Academic ProgramsInstitute for Student SuccessUniversity of ConnecticutStorrsUnited States Louis Stokes Alliance for Minority Participation Institute for Student SuccessUniversity of ConnecticutStorrsUnited States Industrial Design Department of Art and Art HistorySchool of Fine ArtsUniversity of ConnecticutStorrsUnited States Materials Science and Engineering Department Center for Clean Energy Engineering and Institute for Materials ScienceUniversity of ConnecticutStorrsUnited States

This perspective article explores challenges of traditional education in science,technology,engineering and math(STEM)as it relates to emerging sustainable energy and artificial intelligence development.A special perspective is given for education of underrepresented and minority students in *** discuss the existing issues and suggest that,for an equitable sustainable education in the area of energy,artificial intelligence and sustainable society in general,science and technology knowledge should be acquired in conjunction with humanities and arts,through a multidisciplinary STEM+Art(STEAM)approach and special programming that supports inclusion of diverse professional,socio-economical,racial and gender *** underscore that infusing technical training with social sciences,arts,ethics,and business prepares future leaders to creatively participate in solving identifiable barriers towards a sustainable *** these are challenges caused by climate change,social tensions,or systematic inequalities,such holistic and sustainable education has the power to ease complex global crises,empower and dignify all people,as well as interrupt environmental degradation.

关键词： STEM STEAM Sustainability Energy AI

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Problems With Solutions: engineering Alkylammonium Additive Reactivity for Durable High-Quality Perovskite Films

Problems With Solutions: Engineering Alkylammonium Additive ...

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IEEE Conference Photovoltaic Specialists (PVSC)

作者： Jack R. Palmer Soichiro Iwamoto Clark Han Connor J. Dolan Hendrik M. Vossler Sean P. Dunfield David P. Fenning Materials Science and Engineering Program UC San Diego La Jolla CA United States Department of NanoEngineering UC San Diego La Jolla CA United States

ISBN: (数字)9781665464260

ISBN: (纸本)9781665475822

Methylammonium chloride (MACl) is used as a volatile additive in most high-efficiency formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs). However, MA is known to irreversibly react with FA to form n-methyl formamidinium (nMFA), which is detrimental to the absorber quality. In this work, we explore a series of alternative primary alkylammonium chlorides (RACls) in an antisolvent-free deposition. We analyze ink reactivity toward FA, film crystallinity, photoluminescence quantum yield (PLQY), and durability under light and heat. We find that the alkyl chain has a significant effect on reaction rate with FA, with isopropylammonium (iPA) showing a 10 times slower reaction rate than MA. Diffraction intensity of the (001) perovskite peak is maximized with ethylammonium (EA) and iPA, then decreases with the increasing alkyl chain length of n-propyl (nPA) and n-butyl (nBA) ammonium. Importantly, films cast from aged solutions containing the alternative RACl additives all formed majority black perovskite α-phase, while the MACl controls did not, highlighting the negative impact of nMFA. PLQY of alternative additives were comparable to pristine MACl and was retained in films made after solution aging. Durability tests of unencapsulated films in inert atmosphere under 0.6-sun illumination and 85°C heating revealed increased stability of the black perovskite α-phase by replacing MA, with iPA and nBA offering the best phase stability. Unoptimized devices prepared with fresh inks containing iPACl deliver performance on par with the MACl control. The results presented herein demonstrate promising alternative volatile additives to replace MACl in FAPbI3-based perovskite solar cells.

关键词： Heating systems Photovoltaic systems Performance evaluation Additives Photovoltaic cells Ink Photoluminescence Aging Perovskites Stability analysis

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Computational inverse design of acoustoplasmonic metasurfaces

arXiv

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arXiv 2025年

作者： Holland, Julia E. Boechler, Nicholas Poulikakos, Lisa V. Department of Mechanical & Aerospace Engineering UC La Jolla San DiegoCA92093-0021 United States Program in Materials Science & Engineering UC La Jolla San DiegoCA92093-0021 United States

Optical and acoustic metasurfaces are two-dimensional arrays of subwavelength elements that locally modulate or phase shift incident waves. Acoustoplasmonic metasurfaces combine the physics of light and sound, producing acoustic wavefronts in response to optical stimuli. Herein, we present a computational inverse acoustoplasmonic metasurface design algorithm for desired optically-generated acoustic wave fields. We consider gold nanoparticles producing spherical acoustic waves in water, and the resulting acoustic wave propagation along the plane containing the nanoparticle array. We demonstrate how our algorithm can be used to design metasurfaces that can be used to achieve complex acoustic wave fields. This includes the design of a single metasurface that produces acoustic wave fields mimicking two different Morse code patterns upon stimulation with two orthogonal polarization states of light. This work provides a new tool for the design of complex optically generated acoustic wavefronts, enabling functionality beyond what would be achievable with off-optical-resonance optoacoustic excitation. Copyright © 2025, The Authors. All rights reserved.

关键词： Acoustic wave propagation

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