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Microwave and Antenna Symposium (IMAS), International

作者： Josef Frankhouse Evans Addo-Mensah Uche Wejinya Department of Mechanical Engineering University of Arkansas - Fayetteville Materials Science and Engineering Graduate Program University of Arkansas - Fayetteville

ISBN: (数字)9798350356359

ISBN: (纸本)9798350356366

In this study, a Terahertz (THz) band antenna which can regulate its own resonant frequency without the requirement of manual adjustment is simulated. A polyvinylidene fluoride (PVDF) substrate is applied onto a rectangular graphene patch antenna. With a voltage potential applied onto the PVDF, the patch antenna can attenuate its frequency by physically changing the shape of the antenna, and in turn its resonant frequency. These antennas are within a 0.1 THz band between 1.32 THz to 1.22 THz measured from a radial bend of a flat surface to r = 75 μm, fitting into a return loss (S11) above -30 dB. Although the return loss did not show consistency, the resonating frequency shifted at a linear rate relative to the cylindrical bending.

关键词： Microwave antennas Patch antennas Graphene Resonant frequency Prototypes Bandwidth Bending Loss measurement Substrates Terahertz communications

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High-quality Mid-infrared Chalcogenide Ring Resonator

High-quality Mid-infrared Chalcogenide Ring Resonator

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CLEO: science and Innovations in CLEO 2024, CLEO: S and I 2024 - Part of Conference on Lasers and Electro-Optics

作者： Lu, Bright Xu, Bo Krueper, Greg Zohrabi, Mo Gopinath, Juliet T. Park, Wounjhang Department of Electrical Computer and Energy Engineering University of Colorado BoulderCO80309 United States Department of Physics University of Colorado BoulderCO80309 United States Materials Science and Engineering Program University of Colorado BoulderCO80309 United States

We report Ge23Sb7S70 chalcogenide ring resonators with up to 8 × 104 quality factors operating around 3.6 µm wavelength fabricated through e-beam lithography. Their rib waveguide geometry can be engineered to support close-to-zero dispersion modes needed for mid-infrared microcomb generation. © Optica Publishing Group 2024

关键词： Infrared devices

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Density Functional Theory Study of Surface Stability and Phase Diagram of Orthorhombic CsPbI3

arXiv

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arXiv 2024年

作者： Li, Kejia Wang, Mengen Department of Electrical and Computer Engineering and Materials Science and Engineering Program SUNY BinghamtonNY13902 United States

CsPbI3 has been recognized as a promising candidate for optoelectronic device applications. To further improve the efficiency of the devices, it is imperative to better understand the surface properties of CsPbI3, which affect charge carrier transport and defect formation properties. In this study, we perform density functional theory calculations to explore the stability of the (001), (110), and (100) surfaces of orthorhombic CsPbI3, considering different stoichiometries and surface reconstructions. Our results show that, under the chemical potentials confined by the thermodynamically stable region of bulk CsPbI3, the CsI-terminated surfaces of (001) and (110) and the stoichiometric surface of (100) are stable. Among these three surfaces, the CsI-terminated (110) surface has the lowest surface energy and no mid-gap states, which benefits the transport properties of the material. © 2024, CC BY-NC-SA.

关键词： Stoichiometry

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Surface modification techniques of membranes to improve their antifouling characteristics:recent advancements and developments

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Frontiers of Chemical science and engineering 2023年第12期17卷 1837-1865页

作者： Muhammad Tawalbeh Haya Aljaghoub Muhammad Qasim Amani Al-Othman Sustainable and Renewable Energy Engineering Department University of SharjahSharjah 27272United Arab Emirates Sustainable Energy&Power Systems Research Centre RISEUniversity of SharjahSharjah 27272United Arab Emirates Industrial Engineering and Engineering Management Department University of SharjahSharjah 27272United Arab Emirates Department of Chemical and Biological Engineering American University of SharjahSharjah 26666United Arab Emirates Materials Science and Engineering Program College of Arts and SciencesAmerican University of SharjahSharjah 26666United Arab Emirates

Extensive research efforts are currently devoted to developing and improving conventional technologies for water treatment. Membrane-based water treatment technologies are among the most preferred options due to their commercial success, simple operation, low energy and space requirements, and high separation efficiency. Despite the advances made in membrane-based technologies, fouling remains a critical challenge. Fouling occurs upon the accumulation of unwanted impurities on the membrane surface and within the membrane pores which results in a significant decline in the membrane permeate flux. To alleviate the operational challenges from fouling, surface modification to develop antifouling membranes appears to be an effective technique. A comprehensive review of the surface modification techniques for the development of antifouling membranes is provided in this paper. Chemical surface modification techniques (grafting and plasma treatment), physical modification techniques (blending, coating, adsorption, and thermal treatment), and combined physical and chemical modification techniques have been discussed. Moreover, the challenges related to surface modification and the future research directions are addressed.

关键词： fouling antifouling membrane surface modification membrane pretreatment

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INTER- AND INTRA-LAMINAR PROPERTIES OF AN AFP POST-PROCESSED THERMOPLASTIC COMPOSITE

INTER- AND INTRA-LAMINAR PROPERTIES OF AN AFP POST-PROCESSED...

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SAMPE 2024 Conference and Exhibition

作者： Yap, Timothy S. Heathman, Nathaniel M. Kirchhoff, Joseph G. Tehrani, Mehran Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX United States Department of Structural Engineering University of California La Jolla San DiegoCA United States Program in Materials Science and Engineering University of California La Jolla San DiegoCA United States

ISBN: (纸本)9781934551455

Transitioning to high-performance thermoplastic composites (TPCs) carries great potential due to their enhanced toughness, ease of repairability, and the possibility of bypassing the need for autoclaves that are essential for curing thermosetting composites. Full consolidation of parts may be achieved in-situ using automated fiber placement (AFP) at slow rates;alternatively, with higher rates, consolidation may only occur following vacuum-bag oven processing (vacuum-bag only or VBO) or compression molding (CM) post-processing. This study investigates the CM of AFP carbon fiber LM-PAEK™ composites at a low pressure of 0.2 MPa to simulate VBO post-processing, focusing on their intra- and inter-laminar behavior. Short-beam strength, fracture toughness modes I and II, and transverse tensile and compressive samples were manufactured via AFP using a fast layup rate, followed by low-pressure CM. As compared to previous studies, post-processing resulted in greater interlaminar bonding. This study demonstrates the viability of TPCs for the next generation of aerospace structures with a relatively simple oven post-processing. © 2024 Soc. for the Advancement of Material and Process engineering. All rights reserved.

关键词： Compression molding

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Investigation of manufacturing conditions of single roll rapidly solidified ribbon for anode materials of magnesium rechargeable batteries

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Keikinzoku/Journal of Japan Institute of Light Metals 2023年第11期73卷 537-544页

作者： Kirimoto, Yuichi Fuke, Kousuke Tsukeda, Tadayoshi Aida, Tetsuo Nemoto, Yasunori Ikeda, Minoru Tabata, Hironobu Kurihara, Hideki Suzuki, Mayumi Department of Nano and Functional Material Science Graduate School of Science and Engineering for Education University of Toyama 3190 Gofuku Toyama-shi-shiToyama Toyama930-8555 Japan Program of Materials Science and Engineering Studies in Science and Engineering Graduate School of Science and Engineering University of Toyama Toyama-shi-shiToyama Toyama Japan Faculty of Sustainable Design Academic Assembly University of Toyama Toyama-shi Toyama-shi-shiToyama Toyama Japan FLOW Science JAPAN Shizuoka Hamamatsu-shi Japan CHUETSU METAL WORKS CO. LTD Nakaniikawa-gun Toyama Japan Saitama Industrial Technology Center Saitama Kawaguchi-shi Japan Department of Mechanical Systems Engineering Faculty of Engineering Toyama Prefectural University Imizu-shi Toyama Japan

Magnesium rechargeable batteries are attracting attention as next-generation rechargeable batteries because of their resource abundance, cost, safety, and high electrical capacity per volume compared to conventional lithium-ion rechargeable batteries. Our joint research team focused not only on the electrochemically active magnesium composition of ribbon for the negative electrode materials of magnesium rechargeable batteries but also on the production process, focused on the single roll type liquid quenching and rapid solidification method, which can be produced at a lower cost. In this study, the optimal processing conditions were examined by comparing CAE analysis with ribbon actually manufactured, with the aim of further improving manufacturing conditions using the same method, such as length discontinuities, thickness, and surface properties of ribbon. We specifically various process parameters such as injection pressure and roll peripheral speed for evaluation. As a result, several linear cracks were observed on the surface of the ribbon as the peripheral speed increased and as the Gap became wider, and the surface properties tended to deteriorate. Also, It was found that the dominant factor in the length of the ribbon was the peripheral speed. As the peripheral speed increased, the length of the ribbon tended to increase. © 2023 Japan Institute of Light Metals. All rights reserved.

关键词： Surface properties

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Enhancement of piezophototronic hydrogen evolution reaction through the polarization of ferroelectric Bi4Ti3O12 microplates

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International Journal of Hydrogen Energy 2024年 50卷 15-25页

作者： Chang, Shun Cheng Chen, Po-Han Chen, Yu-Ching Wu, Jyh Ming Department of Materials Science and Engineering National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan High Entropy Materials Center National Tsing Hua University Section 2 Kuang Fu Road 101 Hsinchu300 Taiwan Ph.D. Program in Prospective Functional Materials Industry National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan

In this study, we analyzed the properties of Bi4Ti3O12 microplates in the context of hydrogen evolution reaction. Piezoresponse force microscopy revealed a typical butterfly curve, indicating that as-synthesized Bi4Ti3O12 exhibits ferroelectric properties. Under ultrasonication, the amount of hydrogen produced by polarized (2000 V) Bi4Ti3O12 increased from 728 to 1349 μmol g−1, which was 1.85 times higher than that generated by unpolarized Bi4Ti3O12. The increase in hydrogen evolution rate may be attributed to the gradual alignment of polarization within the ferroelectric domains of Bi4Ti3O12. Moreover, with synergistic piezophototronic activity, the amount of hydrogen produced by Bi4Ti3O12 was further increased to 1478 μmol g−1, which was 200% higher than that generated by unpolarized Bi4Ti3O12. Theoretical calculations revealed that Bi4Ti3O12 microplates exhibit a high piezoelectric potential along the x-axis, which is consistent with the spontaneous polarization of the microplates. By applying an external polarization field, ferroelectric polarization was activated to effectively separate free charges and extend carrier lifetime (from 0.6 to 0.84 ns). The application of an external electric field to ferroelectric Bi4Ti3O12 appears to be a favorable strategy for enhancing its piezophototronic activity. Our findings may facilitate future studies in the fields of environmental science and renewable energy. © 2023 Hydrogen Energy Publications LLC

关键词： Bismuth compounds

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Using 4D-STEM to Map 3D Morphologies of 2D materials

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Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2023年第1期29卷 262-263页

作者： Mireles, Adan Shi, Chuqiao Park, Jeongwon Shin, Bongki Sung, Suk Hyun Ophus, Colin Hovden, Robert Kang, Kibum Han, Yimo Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX United States Department of Materials Science and NanoEngineering Rice University Houston TX United States Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Department of Materials Science and Engineering University of Michigan Ann Arbor MI United States National Center for Electron Microscopy Molecular Foundry Lawrence Berkeley National Laboratory Berkeley CA United States

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Temperature-Responsive and Passive Wireless Mechanical Metamaterial Sensors 14

Temperature-Responsive and Passive Wireless Mechanical Metam...

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14th International Workshop on Structural Health Monitoring: Designing SHM for Sustainability, Maintainability, and Reliability, IWSHM 2023

作者： Naidu, Vishnu R. Park, Yujin Loh, Kenneth J. Materials Science and Engineering Program University of California La Jolla San DiegoCA92093 United States Department of Structural Engineering University of California La Jolla San DiegoCA92093 United States

ISBN: (纸本)9781605956930

Knowing the location and environmental conditions of sailors that have fallen overboard can greatly facilitate open water search and rescue operations. Currently, active sensors that trigger an alarm when a sailor falls overboard exist, and it works by detecting a loss of signal from a transmitter. However, their applications have been limited because of the dependence on a working battery, as well as the fact that sailor location cannot be tracked beyond the one-time loss-of-signal event. In this study, a passive, person-overboard sensing concept is proposed, and the focus is to demonstrate monitoring of seawater conditions. The passive sensor was designed by incorporating a temperature-responsive hydrogel with an auxetic star pattern unit cell geometry, which transforms from a two- to three-dimensional geometry when immersed in low temperature liquid. First, the passive sensor was formed by incorporating a temperature-responsive hydrogel at opposite ends of the star pattern. The time-dependent swelling and de-swelling behavior of the copolymer hydrogel was characterized to understand the mechanical strains induced after exposure to low temperature water. Second, the design of the star pattern geometry was optimized, and artificial imperfections in the form of notches were employed to allow shape transformation to take place at appropriate and minimal applied strains. The vision is that these shape morphing structures with integrated antennas can serve as passive sensors, which, when interrogated by a remote reader, can be used to monitor how long overboard sailors have been in a low-temperature open sea environment. © 2023 by DEStech Publi cations, Inc. All rights reserved

关键词： Water temperature

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Specular inverse Faraday effect in transition metals

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Physical Review materials 2023年第12期7卷 125202-125202页

作者： Victor H. Ortiz Shashi B. Mishra Luat Vuong Sinisa Coh Richard B. Wilson Department of Mechanical Engineering and Materials Science and Engineering Program University of California Riverside 92521 CA United States

The inverse Faraday effect is an optomagnetic phenomenon that describes the ability of circularly polarized light to induce magnetism in solids. The capability of light to control magnetic order in solid state materials and devices is of interest for a variety of applications, such as magnetic recording, quantum computation, and spintronic technologies. However, significant gaps in understanding about the effect persist, such as what material properties govern the magnitude of the effect in metals. In this work, we report time-resolved measurements of the specular inverse Faraday effect in nonmagnetic metals, i.e., the magneto-optic Kerr effect induced by circularly polarized light. We measure this specular inverse Faraday effect in Cu, Pd, Pt, W, Ta, and Au at a laser wavelength of 783 nm. For Ta and W, we investigate both α and β phases. We observe that excitation of these metals with circularly polarized light induces significant circular dichroism. This nonlinear magneto-optical response to circularly polarized light is an order of magnitude larger in α-W than other metals, e.g., Pt or Au, and is greater than nearly all other reported values for the inverse Faraday effect in other materials. Our results benchmark the range of the inverse Faraday effect that can be observed in nonmagnetic metals and provide insight into what material properties govern the inverse Faraday effect in metals.

关键词： Light-induced magnetic effects Magneto-optics Ultrafast optics Magneto-optical Kerr effect Sputtering Ultrafast femtosecond pump probe

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