检索结果-内蒙古大学图书馆

Enhancing mechanical properties and corrosion performance of AA6063 aluminum alloys through constrained groove pressing technique

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2020年第7期30卷 1790-1802页

作者： Ren-jie FAN Shokouh ATTARILAR Mahmoud SHAMSBORHAN Mahmoud EBRAHIMI Ceren GODE Hatice VarolOZKAVAK Department of Mechanical Engineering Tongling Vocational and Technical CollegeTongling 244061China School of Metallurgy and Materials Engineering Iran University of Science and TechnologyTehranIran Department of Engineering Mahabad BranchIslamic Azad UniversityMahabadIran Department of Mechanical Engineering University of ZakhoZakhoKurdistan RegionIraq Department of Mechanical Engineering Faculty of EngineeringUniversity of MaraghehMaraghehIran School of Denizli Vocational Technology Program of MachinePamukkale UniversityDenizliTurkey Department of Mechanical and Metal Technology Technical Sciences Vocational SchoolIsparta University of Applied SciencesIspartaTurkey

The use of a constrained groove pressing(CGP) method to plastically deform AA6063 aluminum alloy led to the improved surface properties. It was found that hardness magnitude is dramatically improved and its uniformity is considerably decreased after the first pass, while subsequent passes result in better hardness behavior for the processed material. Also, the elongated grains formed in the first pass of the CGP are gradually converted to the equiaxed counterparts by adding pass numbers. Eventually, higher corrosion resistance of the sample by imposing the CGP process is related to the quick formation of passivation film and the change in the morphology of the second phase and precipitates which hinder their electrochemical reactions and decrease the potential localized attack sites.

关键词： mechanical properties corrosion resistance aluminum alloy constrained groove pressing technique grain refinement hardness distribution homogeneity

Breakdown of Conventional Winding Number Calculation in One-Dimensional Lattices with Interactions Beyond Nearest Neighbors

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Alisepahi, Amir Rajabpoor Sarkar, Siddhartha Sun, Kai Ma, Jihong Department of Mechanical Engineering University of Vermont 33 Colchester Ave BurlingtonVT05405 United States Department of Physics University of Michigan 450 Church St. Ann ArborMI48109 United States Department of Physics University of Vermont 33 Colchester Ave BurlingtonVT05405 United States Materials Science Program University of Vermont 33 Colchester Ave BurlingtonVT05405 United States

Topological insulators hold promises to realize exotic quantum phenomena in electronic, photonic, and phononic systems. Conventionally, topological indices, such as winding numbers, have been used to predict the number of topologically protected domain-wall states (TPDWSs) in topological insulators, a signature of the topological phenomenon called bulk-edge correspondence. Here, we demonstrate theoretically and experimentally that the number of TPDWSs in a mechanical Su-Schrieffer-Heeger (SSH) model can be higher than the winding number depending on the strengths of beyond-nearest-neighbor interactions, revealing the breakdown of the winding number prediction. Alternatively, we resort to the Berry connection to accurately characterize the number and spatial features of TPDWSs in SSH systems, further confirmed by the Jackiw-Rebbi theory proving that the multiple TPDWSs correspond to the bulk Dirac cones. Our findings deepen the understanding of complex network dynamics and offer a generalized paradigm for precise TPDWS prediction in potential applications involving localized vibrations, such as drug delivery and quantum computing. © 2023, CC BY.

关键词： Topology

Saturable intercalation doping enables scalable and selective graphene gas sensors on plastic

学校读者我要写书评

暂无评论

Chemical engineering Journal 2025年 515卷

作者： Kwon, Bitnuri Lee, Jung Hun Jo, Sae Byeok Hwang, Jinhyun Lee, Donggeun Cha, Jonghyun Lim, Soomook Suk, Ji Won Lee, Wi Hyoung Department of Organic and Nano System Engineering Konkuk University Seoul05029 Cuba Department of Materials Science and Engineering and the Materials Research Center Northwestern University 2220 Campus Drive EvanstonIL60208-3108 United States School of Chemical Engineering Sungkyunkwan University Suwon16419 Cuba Sungkyunkwan University Suwon16419 Cuba Advanced Materials Program Department of Materials Science and Engineering Konkuk University Seoul05029 Cuba School of Mechanical Engineering Sungkyunkwan University Suwon16419 Cuba Department of Smart-Fab. Technology Sungkyunkwan University Suwon16419 Cuba Department of Materials Science and Engineering Konkuk University Seoul05029 Cuba

Developing highly sensitive and selective gas sensors for nitrogen dioxide (NO2) detection remains crucial for environmental monitoring and public health protection. Graphene-based chemiresistive sensors show promise due to their exceptional electronic properties and high surface area, which enhance gas adsorption. However, they face persistent challenges in selectivity, stability, and sensitivity characteristics. This study presents a facile one-step molecular intercalation doping approach that can effectively overcome these limitations. By intercalating carefully selected dopant molecules between graphene and flexible substrates during the wet-transfer process, we achieve uniform doping distribution while maintaining intrinsic carrier mobility. The resulting sensors demonstrate remarkable NO2 detection capabilities with a limit of detection of 1 ppb at room temperature. Importantly, the intercalated devices exhibit exceptional stability over extended periods of time and show minimal cross-sensitivity to common interfering gases. Moreover, the sensors retain their sensing characteristics under mechanical deformation, including fully transparent gas sensors with a dogbone structure, thereby enabling seamless integration into wearable monitoring systems. Our scalable fabrication process and comprehensive understanding of the intercalation doping mechanism provide a practical pathway for the development of reliable, flexible gas sensors capable of addressing real-world environmental and healthcare challenges. © 2025 Elsevier B.V.

关键词： pH sensors

Mid-wave to near-IR optoelectronic properties and epsilon-near-zero behavior in indium-doped cadmium oxide

学校读者我要写书评

暂无评论

Physical Review materials 2021年第3期5卷 035202-035202页

作者： Angela Cleri John Tomko Kathleen Quiambao-Tomko Mario V. Imperatore Yanglin Zhu J. Ryan Nolen Joshua Nordlander Joshua D. Caldwell Zhiqiang Mao Noel C. Giebink Kyle P. Kelley Evan L. Runnerstrom Patrick E. Hopkins Jon-Paul Maria Penn State University Department of Materials Science and Engineering University Park Pennsylvania 16802 USA University of Virginia Department of Materials Science and Engineering Charlottesville Virginia 22904 USA Penn State University Department of Electrical Engineering University Park Pennsylvania 16802 USA Penn State University Department of Physics University Park Pennsylvania 16802 USA Vanderbilt University Interdisciplinary Materials Science Program Nashville Tennessee 37235 USA Oak Ridge National Laboratory Center for Nanophase Materials Science Oak Ridge Tennessee 37830 USA Army Research Office DEVCOM US Army Research Laboratory Research Triangle Park North Carolina 27709 USA University of Virginia Department of Mechanical and Aerospace Engineering Charlottesville Virginia 22904 USA University of Virginia Department of Physics Charlottesville Virginia 22904 USA

Indium-doped cadmium oxide (In:CdO) thin films exhibit tunable epsilon-near-zero (ENZ) modal frequencies across a wide spectral range, bridging the mid-wave and near-infrared (IR). In:CdO thin films are prepared by reactive cosputtering from metallic Cd and In targets using high-power impulse magnetron sputtering (HiPIMS) and radio frequency sputtering, respectively. Using this approach, CdO thin films with carrier concentrations ranging from 2.3×1019 to 4.0×1020cm–3 and mobilities ranging from 300 to 400cm2/Vs are readily achieved. UV-VIS absorption spectra are used to measure optical bandgap, revealing a Burstein-Moss shift of 0.58 eV across the doping range investigated. Optical measurements demonstrate the tunability of near-perfect plasmonic ENZ absorption across the mid-wave and into the near-IR spectral ranges by controlling the carrier concentration through doping, while tuning the film thickness for impedance matching. In comparison to other dopants that can be introduced to HiPIMS-deposited CdO, In offers the largest range of carrier concentrations while maintaining high mobility, thus allowing for the widest accessibility of the IR spectrum of a single plasmonic material grown by sputtering.

关键词： Plasmonics Reflectivity X-ray diffraction

Weak-value amplification for the optical signature of topological phase transitions

学校读者我要写书评

暂无评论

Photonics Research 2020年第12期8卷 I0015-I0022页

作者： WEIJIE WU SHIZHEN CHEN WENHAO XU ZHENXING LIU RUNNAN LOU LIHUA SHEN HAILU LUO SHUANGCHUN WEN XIAOBO YIN Laboratory for Spin Photonics School of Physics and ElectronicsHunan UniversityChangsha 410082China Department of Mechanical Engineering University of ColoradoBoulderColorado 80309USA Materials Science and Engineering Program University of ColoradoBoulderColorado 80309USA

We show that weak measurements can be used to measure the tiny signature of topological phase *** signature is an in-plane photonic spin Hall effect,which can be described as a consequence of a Berry *** is also parallel to the propagation direction of a light *** imaginary part of the weak value can be used to analyze ultrasmall longitudinal phase shifts in different topological *** optical signatures are related to the Chern number and bandgaps;we also use a preselection and postselection technique on the spin state to enhance the original *** weak amplification technique offers a potential way to determine the spin and valley properties of charge carriers,Chern numbers,and topological phases by direct optical measurement.

关键词： signature topological transitions

The connection between polymer collapse and the onset of jamming

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Grigas, Alex T. Fisher, Aliza Shattuck, Mark D. O’Hern, Corey S. Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States

Previous studies have shown that the interiors of proteins are densely packed, reaching packing fractions that are as large as those found for static packings of individual amino-acid-shaped particles. How can the interiors of proteins take on such high packing fractions given that amino acids are connected by peptide bonds and many amino acids are hydrophobic with attractive interactions? We investigate this question by comparing the structural and mechanical properties of collapsed attractive disk-shaped bead-spring polymers to those of three reference systems: static packings of repulsive disks, of attractive disks, and of repulsive disk-shaped bead-spring polymers. We show that attractive systems quenched to temperatures below the glass transition T Tg and static packings of both repulsive disks and bead-spring polymers possess similar interior packing fractions. Previous studies have shown that static packings of repulsive disks are isostatic at jamming onset, i.e. the number of contacts Nc matches the number of degrees of freedom, which strongly influences their mechanical properties. We find that repulsive polymers are hypostatic at jamming onset, but effectively isostatic when including quartic modes. While attractive disk and polymer packings are hyperstatic, we identify a definition for interparticle contacts for which they can also be considered as effectively isostatic. As a result, we show that the mechanical properties (e.g. scaling of the potential energy with excess contact number and low-frequency contribution to the density of vibrational modes) of weakly attractive disk and polymer packings are similar to those of isostatic repulsive disk and polymer packings. Our results demonstrate that static packings generated via attractive collapse or compression of repulsive particles possess similar structural and mechanical properties. © 2023, CC BY.

关键词： Amino acids

Moiré exciton polaron engineering via twisted hBN

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Cho, Minhyun Datta, Biswajit Han, Kwanghee Chand, Saroj B. Adak, Pratap Chandra Yu, Sichao Li, Fengping Watanabe, Kenji Taniguchi, Takashi Hone, James Jung, Jeil Grosso, Gabriele Kim, Young Duck Menon, Vinod M. Department of Physics Kyung Hee University 26 Kyungheedae-ro Seoul02447 Korea Republic of Department of Physics City College of New York New YorkNY10031 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Physics Department of Smart Cities University of Seoul Seoul02504 Korea Republic of Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Department of Mechanical Engineering Columbia University New YorkNY10027 United States Physics Program Graduate Center City University of New York New YorkNY10016 United States Department of Information Display Kyung Hee University Seoul02447 Korea Republic of

Twisted hexagonal boron nitride (thBN) exhibits emergent ferroelectricity due to the formation of moiré superlattices with alternating AB and BA domains. These domains possess electric dipoles, leading to a periodic electrostatic potential that can be imprinted onto other 2D materials placed in its proximity. Here we demonstrate the remote imprinting of moiré patterns from twisted hexagonal boron nitride (thBN) onto monolayer MoSe2 and investigate the resulting changes in the exciton properties. We confirm the imprinting of moiré patterns on monolayer MoSe2 via proximity using Kelvin probe force microscopy (KPFM) and hyperspectral photoluminescence (PL) mapping. By developing a technique to create large ferroelectric domain sizes ranging from 1 µm to 8.7 µm, we achieve unprecedented potential modulation of ∼ 387±52 meV. We observe the formation of exciton polarons due to charge redistribution caused by the antiferroelectric moiré domains and investigate the optical property changes induced by the moiré pattern in monolayer MoSe2 by varying the moiré pattern size down to ∼110 nm. Our findings highlight the potential of twisted hBN as a platform for controlling the optical and electronic properties of 2D materials for optoelectronic and valleytronic applications. © 2024, CC BY-NC-ND.

关键词： Boron nitride

Quantifying thermo-electro-mechanics for manipulation and rotation of single dielectric particles under laser illumination

学校读者我要写书评

暂无评论

Quantifying thermo-electro-mechanics for manipulation and ro...

2020 Frontiers in Optics Conference, FiO 2020

作者： Kollipara, Pavana Siddhartha Lin, Linhan Chen, Zhihan Peng, Xiaolei Liu, Yaoran Zheng, Yuebing Walker Department of Mechanical Engineering The University of Texas at Austin TX78751 United States Materials Science and Engineering Program Texas Materials Institute The University of Texas at Austin TX78751 United States State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision Instrument Tsinghua University Beijing100084 China

Spatially varying thermoelectric field around nanoparticles in laser-induced thermal gradients is derived for the first time. The proposed theory is experimentally validated for optical trapping, rotation, and pulling... 详细信息

ISBN: (纸本)9781943580804

关键词： Nanoparticles

Experimental Investigation of Lord Kelvin’s Isentropic Cooling and Heating Expression in Tensile Bars for Two engineering Alloys

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Burns, S.J. Pratt, Christine E. Carrock, Joseph Gagnon, Jean-Philippe Sefkow, A.B. Materials Science Program College of Arts Science and Engineering University of Rochester RochesterNY14627 United States Department of Mechanical Engineering University of Rochester 236 Hopeman Hall RochesterNY14627 United States Field Application Engineering Telops GenevaNY14456 United States Systems Engineering Telops 100-2600 St-Jean-Baptiste Ave. QuébecQCG2E 6J5 Canada Laboratory for Laser Energetics University of Rochester 250 E. River Rd. RochesterNY14623 United States Department of Physics and Astronomy University of Rochester 206 Bausch and Lomb Hall RochesterNY14627 United States Department of Computer Science University of Rochester 2513 Wegmans Hall RochesterNY14627 United States

Solids when rapidly and elastically stressed change temperature, the effect proposed by Lord Kelvin is adiabatic thermo-elastic cooling or heating depending on the sign of the stress. A fast sensitive IR camera has measured temperature both decreasing and increasing. Temperature measurements made from the reversible, elastic part of the stress-strain curve during fast uniaxial tensile loading have been investigated. The isentropic temperature cooling from the loading curve is recovered by heating after the specimen fractures when the load is released. These measurements establish for the first time isentropic thermal recovery in two engineering alloys. The materials tested are an AISI 4340 steel and an aluminum 2024 alloy. Measurements of the isentropic thermo-elastic stress cooling are -0.61 K/GPa for steel and -1.7 K/GPa for aluminum alloy. The isentropic thermo-elastic stress heating is -1.16 K/GPa for steel and -1.6 K/GPa for aluminum alloy. These values are compared to Lord Kelvin’s theoretical thermodynamic prediction. Comparisons are also to equations of state tables. The experimental values are slightly below theoretical predictions. The isentropic, elastic part of the temperature is fully recoverable even after extensive plastic deformation upon fracture. Copyright © 2023, The Authors. All rights reserved.

关键词： Cooling