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SSRN 2024年

作者： Balica, Naasson Matheus Pereira Almeida, Larissa Solano Rossino, Luciana Sgarbi Pupim, Denise Monção, Renan Matos Costa, Thércio Henrique de Carvalho Santos, Rafaela Luiz Pereira Sousa, Rômulo Ribeiro Magalhães Nunes, Lívio César Cunha Federal University of Piauí Technology Center Graduate Program in Materials Science and Engineering Avenida Universitária s/n Ininga PI Teresina Brazil Federal University of São Carlos Graduate Program in Materials Science SP Sorocaba Brazil University of São Paulo Ribeirão Preto School of Dentistry Avenida do Café SP Ribeirão Preto Brazil Federal University of Rio Grande do Norte Technology Center Department of Mechanical Engineering University Campus Natal RN Lagoa Nova Brazil

Cobalt-chromium and nickel-chromium metal alloys have been widely used as biomaterials in the dental field due to their excellent physical-mechanical properties and biocompatibility, as well as the low cost of the material. However, in unfavorable environments, such as the oral cavity, these dental prostheses composed of these alloys can suffer alterations in their structure where they can undergo rapid changes with the surface corrosion process, which can vary with pH and temperature, typically related to changes in the patient's diet. The aim of this work is to carry out a comparative study between the cathodic cage (CC) and hollow cathode (HC) methods, in which a plasma deposition treatment of titanium nitride (TiN) thin films was carried out on CoCr and NiCr samples, in order to subsequently evaluate their surface characteristics and tribological properties in relation to each method. The samples were characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM/EDS) and micro abrasive wear tests on each sample from the three groups of alloys mentioned. It was observed that the TiN films provided greater resistance to the wear mechanism of all the samples, where through the characterizations, it can be inferred that the two types of treatments carried out on the samples are suitable for dental applications. © 2024, The Authors. All rights reserved.

关键词： Chromium alloys

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Phase Transitions of the CU6Sn5 Phase Under Electric Currents

Phase Transitions of the CU6Sn5 Phase Under Electric Current...

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International Conference on Electronics Packaging (ICEP)

作者： Shubhayan Mukherjee Yu-Chen Liu Shih-Kang Lin Department of Materials Science and Engineering National Cheng Kung University Tainan Taiwan Hierarchical Green-Energy Materials (Hi-GEM) Research Centre National Cheng Kung University Tainan Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan Taiwan Department of Mechanical Engineering National Cheng Kung University Tainan Taiwan

ISBN: (数字)9784991191190

ISBN: (纸本)9798331514747

The performance and reliability of interfacial regions in electronic solder joints are critical for the durability of lead-free solder systems. The intermetallic compound $\text{Cu}_{6}\text{Sn}_{5}$ , which forms at the interface between Sn-based solders and Cu substrates, exists in two crystal structures: the low-temperature monoclinic phase $(\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5})$ and the high-temperature hexagonal phase $(\eta-\text{Cu}_{6}\text{Sn}_{5})$ . Although the thermal behavior of these phases is well-documented, the effects of electric current on the stability and mechanical properties of $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ remain less understood. This study investigates the impact of electric current on the microstructural evolution of $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ through high-resolution transmission electron microscopy (HR-TEM) following the synchrotron radiation-based X-ray diffraction (SR-XRD). Single-phase $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ samples were subjected to a current density of 1.5 x 10 3 A/cm 2 for 5 hours. Microstructural observations from HR-TEM, following SR-XRD, reveal significant insights into the behavior of monoclinic $\eta^{\prime}-\text{Cu}_{6}\text{Sn}_{5}$ under electric current stressing. These findings offer insights into the relationship between electric current and phase stability in interfacial compounds, which could enhance the reliability of solder joints in advanced electronic systems.

关键词： X-ray scattering Synchrotrons High-resolution transmission electron microscopy materials reliability X-ray diffraction Stability analysis Compounds Current Soldering Thermal stability

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Interfacial thermal transport in spin caloritronic material systems

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Physical Review materials 2021年第11期5卷 114403-114403页

作者： Frank Angeles Qiyang Sun Victor H. Ortiz Jing Shi Chen Li Richard B. Wilson Department of Mechanical Engineering and Materials Science and Engineering Program University of CaliforniaRiverside California 92521 USA Department of Physics and Astronomy Program University of California Riverside California 92521 USA

Interfaces often govern the thermal performance of nanoscale devices and nanostructured materials. As a result, accurate knowledge of thermal interface conductance is necessary to model the temperature response of nanoscale devices or nanostructured materials to heating. Here, we report the thermal boundary conductance between metals and insulators that are commonly used in spin-caloritronic experiments. We use time-domain thermoreflectance to measure the interface conductance between metals such as Au, Pt, Ta, Cu, and Al with garnet and oxide substrates, e.g., NiO, yttrium iron garnet (YIG), thulium iron garnet (TmIG), Cr2O3, and sapphire. We find that, at room temperature, the interface conductance in these types of material systems range from 50 to 300MWm−2K−1. We also measure the interface conductance between Pt and YIG at temperatures between 80 and 350 K. At room temperature, the interface conductance of Pt/YIG is 170MWm−2K−1 and the Kapitza length is ∼40 nm. A Kapitza length of 40 nm means that, in the presence of a steady-state heat current, the temperature drop at the Pt/YIG interface is equal to the temperature drop across a 40-nm-thick layer of YIG. At 80 K, the interface conductance of Pt/YIG is 60MWm−2K−1, corresponding to a Kapitza length of ∼300 nm.

关键词： Thermal conductivity

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Formation and Oer Properties of Nano-Porous Concentrated Tivzrnbcofe Alloy

SSRN

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SSRN 2024年

作者： Jorge, Alberto M. Chatenet, Marian Roche, Virginie Berthomé, Gregory Champion, Yannick LEPMI Grenoble38000 France Univ. Grenoble Alpes CNRS Grenoble INP SIMaP Grenoble38000 France Federal University of Sao Carlos Graduate Program of Materials Science and Engineering DEMa Sao Carlos13565-905 Brazil

A nano-porous Ti25 V0.5Zr13Nb51Co6Fe4 metallic alloy was produced by de-alloying (Ti31V26Zr12Nb26Co5)50Fe50. The material was characterized using X-ray diffraction and SEM imaging showing complex concentrated solid solution and interesting OER properties were revealed from cyclic voltammetry. X-ray photoelectron spectroscopy shows a significant content of Fe-doped Co(OH)2 at the surface of the nanoporous alloy that explains the high OER activity. Nanoporous structure in particular nanosized ligaments and surface curvature are identified in connexion to the OER properties. © 2024, The Authors. All rights reserved.

关键词： Cyclic voltammetry

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Electronic and Optical Excitations in van der Waals materials from a Non-Empirical Wannier-Localized Optimally-Tuned Screened Range-Separated Hybrid Functional

arXiv

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arXiv 2024年

作者： Camarasa-Gómez, María Gant, Stephen E. Ohad, Guy Neaton, Jeffrey B. Ramasubramaniam, Ashwin Kronik, Leeor Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovoth7610001 Israel Department of Physics University of California BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute at Berkeley University of California BerkeleyCA94720 United States Department of Mechanical and Industrial Engineering University of Massachusetts Amherst AmherstMA01003 United States Materials Science and Engineering Graduate Program University of Massachusetts AmherstMA01003 United States

Accurate prediction of electronic and optical excitations in van der Waals (vdW) materials is a long-standing challenge for density functional theory. The recently proposed Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional has proven successful in non-empirical determination of electronic band gaps and optical absorption spectra for various covalent and ionic crystals. However, for vdW materials the tuning of the material- and structure-dependent functional parameters has, until now, only been attained semi-empirically. Here, we present a non-empirical WOT-SRSH approach applicable to vdW materials, with the optimal functional parameters transferable between monolayer and bulk. We apply this methodology to prototypical vdW materials: black phosphrous, moldybdenum disulfide, and hexagonal boron nitride (in the latter case including zero-point renormalization). We show that the WOT-SRSH approach consistently achieves accuracy levels comparable to experiments and ab initio many-body perturbation theory (MBPT) calculations for band structures and optical absorption spectra, both on its own and as an optimal starting point for MBPT calculations. Copyright © 2024, The Authors. All rights reserved.

关键词： Energy gap

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Bacterial Mobility and Motility in Porous Media Mimicked By Microspheres

SSRN

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SSRN 2022年

作者： Shrestha, Diksha Ou, Jun Rogers, Ariel Jereb, Amani Wang, Yong Department of Physics Cell and Molecular Graduate Program Materials Science and Engineering Program University of Arkansas FayettevilleAR72701 United States Department of Environmental Resources Engineering Mechanical Engineering Program California State Polytechnic University Humboldt ArcataCA95521 United States

Bacterial motion in porous media are essential for their survival, proper functioning, and variousapplications. Here we investigated the motion of Escherichia coli bacteria in microsphere-mimicked porousmedia. We observed reduced bacterial velocity and enhanced directional changes of bacteria as the densityof microspheres increased, while such changes happened mostly around the microspheres and due to thecollisions with the microspheres. More importantly, we established and quantified the correlation betweenthe bacterial trapping in porous media and the geometric confinement imposed by the microspheres. In addition,numerical simulations showed that the active Brownian motion model in the presence of microspheresresulted in bacterial motion that are consistent with the experimental observations. Our study suggested thatit is important to distinguish the ability of bacteria to move easily – bacterial mobility – from the abilityof bacteria to move independently – bacteria motility. Our results showed that bacterial motility remainssimilar in porous media, but bacterial mobility was significantly affected by the pore-scale confinement. © 2022, The Authors. All rights reserved.

关键词： Microspheres

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Ultrafast measurements of the interfacial spin Seebeck effect in Au and rare-earth iron-garnet bilayers

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Physical Review materials 2021年第7期5卷 074401-074401页

作者： Víctor H. Ortiz Michael J. Gomez Yawen Liu Mohammed Aldosary Jing Shi Richard B. Wilson Department of Mechanical Engineering and Materials Science and Engineering Program University of California Riverside California 92521 USA Department of Physics and Astronomy Program University of California Riverside California 92521 USA

We investigate picosecond spin currents across Au/iron-garnet interfaces in response to ultrafast laser heating of the electrons in the Au film. In the picoseconds after optical heating, interfacial spin currents occur due to an interfacial temperature difference between electrons in the metal and magnons in the insulator. We report measurements of this interfacial longitudinal spin Seebeck effect between Au and rare-earth iron-garnet insulators, i.e., RE3Fe5O12, where RE is Y, Eu, Tb, Tm. By systematically varying the rare-earth element, we modify the total magnetic moment of the iron garnet. We use time-domain thermoreflectance measurements to characterize the thermal response of the bilayer to ultrafast optical heating. We use time-resolved magneto-optic Kerr effect measurements of the Au layer to measure the time evolution of spin accumulation in the Au film. Replacing Y with other rare earths enhances the electron-magnon conductance Ge−m at the Au iron-garnet interface by as much as a factor of 3. The electron-magnon conductance does not follow the trend of either the total magnetization of the iron garnet or the magnetic moment of the rare earth.

关键词： Magneto-optical Kerr effect Magnons Spin Seebeck effect Spin polarization Ultrafast magnetic effects

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Customizable wave tailoring materials enabled by nonlinear bilevel inverse design

arXiv

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arXiv 2024年

作者： MacNider, Brianna Xiu, Haning Qian, Kai Frankel, Ian Kim, Hyunsun Alicia Boechler, Nicholas Department of Mechanical and Aerospace Engineering University of California La Jolla San DiegoCA92093 United States Department of Structural Engineering University of California La Jolla San DiegoCA92093 United States Program in Materials Science and Engineering University of California La Jolla San DiegoCA92093 United States

Passive transformation of waves via nonlinear systems is ubiquitous in settings ranging from acoustics to optics and electromagnetics. Passivity is of particular importance for responding rapidly to stimuli and nonlinearity enormously expands signal transformability compared to linear systems due to the breaking of superposition. It is well known that different types of nonlinearity yield vastly different effects on propagating signals, which raises the question of "what precise nonlinearity is the best for a given wave tailoring application?" Considering a one-dimensional spring-mass chain as a testbed, we couple the shape optimization of structures for tailored nonlinear constitutive responses with reduced-order nonlinear dynamical inverse design. Using minimization of peak kinetic energy transmission from impact as a case study, we identify ideal nonlinear constitutive responses and the geometries needed to achieve them. As part of this, we show the large sensitivity of this metric to small changes in nonlinearity, and thus the need for high precision, free-form nonlinearity tailoring. We validate our predictions using impact experiments in a chain of nonlinear springs and masses. This work sets the foundation for broader passive nonlinear mechanical wave tailoring material design, with applications to computing, signal processing, shock mitigation, and autonomous materials. © 2024, CC BY-NC-ND.

关键词： Kinetic energy

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Subwavelength-Engineered Antislot Photonic Crystals in a Silicon Photonics Foundry for On-chip Communications

Subwavelength-Engineered Antislot Photonic Crystals in a Sil...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Kellen P. Arnold Joshua A. Allen Sami I. Halimi Landen D. Ryder Francis O. Afzal Yusheng Bian Abdelsalam Aboketaf Takako Hirokawa Kevin Dezfulian Michal Rakowski Rod Augur Karen Nummy Sharon M. Weiss Interdisciplinary Materials Science Program Vanderbilt University Nashville TN USA Department of Electrical and Computer Engineering Vanderbilt University Nashville TN USA NASA Goddard Space Flight Center Greenbelt MD US GlobalFoundries Malta NY USA

We report scalable foundry fabrication and characterization of photonic crystal nanobeam waveguides incorporating subwavelength-scale dielectric antislot unit cells. This work enables enhanced light-matter interaction... 详细信息

ISBN: (纸本)9798350369311

关键词： Mach-Zehnder interferometers Optical device fabrication Photonic crystals Waveguide lasers Lasers and electrooptics Electro-optic modulators Silicon photonics Foundries System-on-chip Electro-optical waveguides

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Flash Sintering of Rhenium at Ambient Temperature in < 1 Minute with Electrical Current

SSRN

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SSRN 2023年

作者： Bamidele, Emmanuel A. Weimer, Alan W. Raj, Rishi Materials Science and Engineering Program University of Colorado BoulderCO80309 United States Department of Mechanical Engineering University of Colorado BoulderCO80309-0427 United States Department Chemical and Biological Engineering University of Colorado BoulderCO80309 United States

We show that rhenium can be sintered from powders to nearly full density (99.96%) by the direct injection of dc current (without a furnace) into dogbone shaped specimens in Ar atmosphere ( © 2023, The Authors. Al... 详细信息

关键词： Sintering

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