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Effect of Temperature and Mischmetal Addition on the Microstructure, Mechanical Andcorrosion Behavior of Crn Hard Coatings Deposited Onto Zk60 Magnesium Alloys Using Hipims

SSRN

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SSRN 2023年

作者： Pereira da Silva, Erenilton Oliveira Junior, William Tavares Avila, Pedro Renato Lima Ribeiro, Josy Kelly Alves dos Santos, Marcos Junio Cortez Maciel, Natalia Mendes Rodrigues, Alisson Pinto, Haroldo Cavalcanti MG Janaúba39447-790 Brazil Department of Engineering Physics Polytechnique Montréal P.O. Box 6079 Station Centre-Ville MontréalQCH3C 3A7 Canada Graduate Program in Materials Science UnB Planaltina Faculty University of Brasilia DF Brasilia70904-910 Brazil SP São Carlos13566-590 Brazil

Magnesium alloys have recently gained popularity due to their low density and suitability for various applications requiring both lightweight and robust mechanical qualities. Nevertheless, their widespread utilization could be improved by their inadequate corrosion resistance. This study examines the deposition of ceramic films using chromium nitride (CrN) via High Power Impulse Magnetron Sputtering (HiPIMS) on ZK60 and ZK60 + 1.5 Mischmetal (MM) at 200°C and 300°C. The morphology and thickness of the CrN films was evaluated by Field Emission Gun-Scanning Electron Microscopy (FEG-SEM) and X-ray Diffraction (XRD), roughness by atomic force microscopy (AFM), and mechanical properties (hardness and elastic modulus) were measured by nanoindentation experiments. Furthermore, the electrochemical impedance spectroscopy (EIS) analysis was used to evaluate the corrosion resistance. Fractured cross-section SEM-FEG images of CrN coatings deposited at 200°C and 300°C revealed differences in thickness and morphology for all samples. ZK60 samples exhibited thicker coatings compared to ZK60+1.5MM, which can be attributed to the stability of intermetallic phases. Increasing temperature resulted in the formation of thinner coatings. Also, at 300°C samples presented different thickness. Surface roughness decreases with temperature, reflecting the formation of refined columnar structures. Hardness and elastic modulus increased with temperature, also presenting different behaviors at 300°C. Corrosion resistance also presented improvement at higher temperatures, with ZK60 outperforming ZK60+1.5MM, as EIS analysis confirmed the denser films enhance corrosion protection, while porous coatings exhibit lower resistance, as was observed for ZK60+1.5MM at 300°C. Results also showed the impact of the thermic stability of the samples on the coating formation, indicating that substrate temperature rises during deposition, leading to possible phase changes in the substrate and, consequently, affe

关键词： Corrosion resistance

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Direct insulator to relativistic quantum Hall transition in graphene

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Physical Review B 2023年第20期108卷 205304-205304页

作者： Ching-Chen Yeh Pin-Chi Liao Dinesh K. Patel Wei-Chen Lin Siang-Chi Wang Albert F. Rigosi Randolph E. Elmquist Chi-Te Liang Department of Physics National Taiwan University Taipei 106 Taiwan Physical Measurement Laboratory National Institute of Standards and Technology (NIST) Gaithersburg Maryland 20899 USA Physikalisch-Technische Bundesanstalt (PTB) Bundesallee 100 Braunschweig 38116 Germany Taiwan International Graduate Program Academia Sinica Taipei 115 Taiwan Department of Engineering and System Science National Tsing Hua University Hsinchu 300 Taiwan Center for Quantum Science and Engineering National Taiwan University Taipei 106 Taiwan Taiwan Consortium of Emergent Crystalline Materials (TCECM) Taipei 106 Taiwan

We present evidence of the direct insulator-quantum Hall transition in monolayer epitaxial graphene, a genuine two-dimensional (2D) system. We studied the transition from an insulating state to a quantum Hall state at a high Landau level filling factor ν=6>3 and the plateau-plateau transition from ν=6 to ν=2. Using scaling theory, the critical exponent κ was determined to be 0.41±0.02 for the direct insulator-quantum Hall transition. This closely aligns with κ=0.42±0.02 from the ν=6 to ν=2 quantum Hall plateau-plateau transition. These findings suggest that the two transitions may belong to the same universality class. While similar transitions have been explored in conventional two-dimensional charge systems, our study provides valuable insights into a truly 2D system, deepening our understanding of these transitions.

关键词： Electrical properties Fermions Landau levels Graphene Hall bar Resistivity measurements

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Multiple degrees-of-freedom programmable soft-matter-photonics: Configuration, manipulation, and advanced applications

Responsive Materials

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Responsive materials 2024年第1期2卷

作者： Yuxian Zhang Zhi-Gang Zheng Quan Li School of Physics East China University of Science and Technology Shanghai China Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast University Nanjing China Materials Science Graduate Program Kent State University Kent Ohio USA Zhi-Gang Zheng and Quan Li.

For centuries, humans have never stopped exploring the nature of light and manipulating it, since light carries multiple information through its intrinsic wave-particle dualism, including wavelength, amplitude, phase, polarization, spin/orbital angular momentum, etc., which determines the physical language and basic manners we perceive the objective world. Conventional optical devices, such as lenses, prisms, and lasers, are composed of solid elements that are bulky, making it difficult to manipulate light dynamically with multiple degrees-of-freedom. Comparatively, some responsive soft matters, especially represented by liquid crystals (LCs), possess distinctive orientational order and spontaneous self-assembled superstructures, enabling the digital programming of microstructures and multiple degrees-of-freedom manipulation of their optical characteristics. The optical manipulation based on these soft superstructures, that is, the “soft-matter-photonics”, is playing an impressive role in integrated functional devices, especially in the present age of information explosion. Herein, we review the latest advances, respectively, in the microstructure configurations, multiple degrees-of-freedom manipulations, and the relevant prospective applications. Additionally, scientific issues and technical challenges that hinder the programing operation and optical manipulations are discussed. Toward a four-dimensional optical manipulation of soft condensed matter, this review may have wide implications on a variety of applications, including the integrated fabrication of compact elements, multi-channel information processing and high-capacity optical communications.

关键词： degree-of-freedom liquid crystal optical manipulation planar optics soft matter

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Terahertz Time-Domain Spectroscopy for Probing DC Conductivity of Single-Layer Graphene

Terahertz Time-Domain Spectroscopy for Probing DC Conductivi...

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Western New York Image Processing Workshop (WNYIPW)

作者： Debamitra Chakraborty Declan Walden Jing Cheng Julia Wallace Kiryl A. Niherysh Andrei V. Felsharuk Donats Erts Ivan Komissarov Roman Sobolewski Materials Science Graduate Program University of Rochester Rochester New York USA Laboratory for Laser Energetics Rochester New York USA Department of Physics and Astronomy University of Rochester Rochester New York USA Department of Biomedical Engineering University of Rochester Rochester New York USA Institute of Chemical Physics University of Latvia Riga Latvia Department of Microtechnology and Nanoscience Chalmers University of Technology Gothenburg Sweden Department of Electrical and Computer Engineering University of Rochester Rochester New York USA

We report preliminary results of extracting electrical parameters like DC conductivity, mobility, and carrier concentration of single-layer graphene using Terahertz time-domain spectroscopy (THz-TDS) in transmission geometry. We utilize a simple Drude model and its extension, the Drude-Smith model, capable of accommodating charge carrier scattering by optical and acoustic phonons to describe the complex conductivity in graphene. We observed that a significant area of the sample scanned followed the Drude-Smith behavior, while at a few locations, the simple Drude behavior prevailed. We identified possible reasons that might contribute to this observation, like defects, the presence of polymer residue on the sample, or the sample strain. This research sheds new light on our understanding of graphene's electrical properties and lays the foundation for future investigations addressing defects and contaminants in graphene samples.

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Designing the pressure-dependent shear modulus using tessellated granular metamaterials

arXiv

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arXiv 2023年

作者： Zhang, Jerry Wang, Dong Jin, Weiwei Xia, Annie Pashine, Nidhi Kramer-Bottiglio, Rebecca Shattuck, Mark D. O’Hern, Corey S. Department of Mechanical Engineering & 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 Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States

Jammed packings of granular materials display complex mechanical response. For example, the ensemble-averaged shear modulus 〈G〉 increases as a power-law in pressure p for static packings of soft spherical particles that can rearrange during compression. We seek to design granular materials with shear moduli that can either increase or decrease with pressure without particle rearrangements even in the large-system limit. To do this, we construct tessellated granular metamaterials by joining multiple particle-filled cells together. We focus on cells that contain a small number of bidisperse disks in two dimensions. We first study the mechanical properties of individual disk-filled cells with three types of boundaries: periodic boundary conditions (PBC), fixed-length walls (FXW), and flexible walls (FLW). Hypostatic jammed packings are found for cells with FLW, but not in cells with PBC and FXW, and they are stabilized by quartic modes of the dynamical matrix. The shear modulus of a single cell depends linearly on p. We find that the slope of the shear modulus with pressure, λc c > 0, as well as λc © 2023, CC BY.

关键词： Elastic moduli

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Mechanical Plasticity of Cell Membranes Enhances Epithelial Wound Closure

arXiv

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arXiv 2023年

作者： Ton, Andrew T. MacKeith, Arthur K. Shattuck, Mark D. O'Hern, Corey S. Department of Physics Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Department of Mechanical Engineering & 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 Applied Physics Yale University New HavenCT06520 United States

During epithelial wound healing, cell morphology near the healed wound and the healing rate vary strongly among different developmental stages even for a single species like Drosophila. We develop deformable particle (DP) model simulations to understand how variations in cell mechanics give rise to distinct wound closure phenotypes in the Drosophila embryonic ectoderm and larval wing disc epithelium. We find that plastic deformation of the cell membrane can generate large changes in cell shape consistent with wound closure in the embryonic ectoderm. Our results show that the embryonic ectoderm is best described by cell membranes with an elasto-plastic response, whereas the larval wing disc is best described by cell membranes with an exclusively elastic response. By varying the mechanical response of cell membranes in DP simulations, we recapitulate the wound closure behavior of both the embryonic ectoderm and the larval wing disc. © 2023, CC BY-NC-ND.

关键词： Cytology

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Mosaic ballistic ceramics: A review

Journal of Alloys and Compounds Communications

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Journal of Alloys and Compounds Communications 2024年 3卷

作者： Alexander B. Dresch Fernando Otávio Pizzatto Janio Venturini Oscar R.K. Montedo Sabrina Arcaro Carlos P. Bergmann Graduate Program in Mining Metallurgical and Materials Engineering Universidade Federal do Rio Grande do Sul Porto Alegre Brazil Graduate Program in Materials Science and Engineering Universidade do Extremo Sul Catarinense Criciúma Brazil School of Natural Sciences Department of Chemistry Technical University of Munich Garching bei München Germany Department of Industrial Engineering Universidade Federal do Rio Grande do Sul Porto Alegre Brazil

The inherent fragility of ceramic materials is an obstacle to producing ceramics that are resistant and hard. Furthermore, the use of monolithic ceramic plate armour for ballistic applications is challenging because the protections need to resist multiple impacts. One of the solutions are mosaic ceramic armour systems, which consist of ceramic tiles arranged side by side. However, there is a wide variety of ceramic tile formats, as well as different dimensions. Unlike monolithic ceramics, mosaic systems present different behaviour when subjected to a ballistic event. As a result, their energy dissipation mechanisms and the properties necessary for this purpose are distinct. The main properties of ceramic tiles are hardness, modulus of elasticity, and fracture toughness, of which the latter, according to the analysis of figures of merit, must be as low as possible, as opposed to hardness and modulus of elasticity, which are desired to be as high as possible. We can efficiently take advantage of brittle fracture mechanisms to absorb the kinetic energy of the projectile during the tile fracture. Furthermore, the gap-filling material is extremely important, as it allows the confinement of the ceramic tiles and reduces the spread of damage. Numerical analysis is a great ally for the study of ballistic ceramics, and countless variables can be considered, enabling results very close to experimental ones at a low cost. Thus, it is possible to understand the key factors for producing more efficient ballistic ceramics as well as obtaining research data that can contribute to the evolution of the ballistic protection sector. In this context, this work presents a review of ceramic mosaics for ballistic amours.

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Giant Deep-Ultraviolet Circular Dichroism in Synthetic Architectures of Ordered Carbon Nanotubes

Giant Deep-Ultraviolet Circular Dichroism in Synthetic Archi...

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2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Doumani, Jacques Lou, Minhan Dewey, Oliver Hong, Nina Fan, Jichao Baydin, Andrey Pasquali, Matteo Yomogida, Yohei Yanagi, Kazuhiro Saito, Riichiro Kono, Junichiro Gao, Weilu Department of Electrical and Computer Engineering Rice University HoustonTX United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX United States Department of Electrical and Computer Engineering The University of Utah Salt Lake CityUT United States Carbon Hub Rice University HoustonTX United States Department of Chemical and Biomolecular Engineering Rice University HoustonTX United States J.A. Woollam Co. LincolnNE United States The Smalley-Curl Institute Rice University HoustonTX United States Department of Chemistry Rice University HoustonTX United States Department of Materials Science and NanoEngineering Rice University HoustonTX United States Department of Physics and Astronomy Tokyo Metropolitan University Tokyo Japan Department Physics Tohoku University Sendai Japan Department Physics and Astronomy Rice University HoustonTX United States

We demonstrate tunable, giant, and structure-induced deep-ultraviolet circular dichroism in macroscopically chiral assemblies of racemic carbon nanotubes prepared using two approaches: mechanical-rotation-assisted vac... 详细信息

ISBN: (纸本)9781957171258

关键词： Dichroism

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Nonclassical Hydrogen Bond-Based Efficient Solid-State Organic Emitters Enabled by a Synergistic Anion and Mechanical Bond Effect

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Angewandte Chemie 2025年第23期137卷

作者： Yi An Ru Zhou Ningjin Zhang Aocheng Chen Junfei Xing Shu Zhang Quan Li Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast University Nanjing 211189 China School of Ecological and Environmental Sciences East China Normal University Shanghai 200062 China Materials Science Graduate Program Kent State University Kent Ohio 44242 USA

Traditional fluorophores often face aggregation-caused quenching (ACQ), limiting their efficacy in high-concentration applications. We demonstrate that a combined effect of anion and mechanical bond can significantly increase fluorescence intensity, up to 14-fold, and a quantum yield of 97.0%. A large number of crystal analyses reveal that this enhancement is primarily driven by nonclassical hydrogen bonds, which stabilize the structure and restrict molecular motion. The versatility of this synergistic effect opens up new avenues for applications, including circularly polarized luminescence (CPL) facilitated by chiral anions and the development of a fluorescence switchable rotaxane shuttle-based stimuli-responsive material.

关键词： Anion Circularly polarized luminescence Mechanical bond Nonclassical hydrogen bond Stimuli-responsive materials

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Effect of Ammonium Formate Addition on Corrosion Behavior of Trivalent Chromium Coatings Electrodeposited in Deep Eutectic Solvents

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International Journal of Electrochemical science 2022年第7期17卷

作者： Sheu, Hung-Hua Lin, Tzu-Te Ger, Ming-Der Department of Chemical and Materials Engineering Chung Cheng Institute of Technology National Defense University Taoyuan Taiwan System Engineering and Technology Program National Yang Ming Chiao Tung University Hsin-Chu Taiwan Graduate School of National Defense Science Chung Cheng Institute of Technology National Defense University Taoyuan Taiwan

The Cr thin films were electrodeposited from trivalent chromium deep eutectic solvents. The conditions of deep eutectic solvents divided into without water (specimen C1), added 15 wt% water (specimen C2), added 15 wt% water with ammonium formate (specimen C3). The HR-TEM shows the structure of “C1” is amorphous structure, and both “C2” and “C3” belong to nano-crystalline structure. The best corrosion resistance of Cr thin film is “C3” which icorr value is approximately at 3.69×10^-7 A/cm², the worst corrosion resistance of Cr thin film is “C1” which icorr value is approximately at 3.05×10^-5 A/cm², it can be attributed to “C3” has a dense structure and “C1” has a loose structure. The EIS analysis also presents “C3” has the best corrosion resistance. The reason for the large difference in corrosion resistance can be attributed to the loose structure of the "C1" thin film and the gaps of film is perpendicular to substrate, the dense structure of the "C3" thin film can effectively protect the substrate. Moreover, the addition of ammonium formate into trivalent chromium deep eutectic solvents will promote the reduction reaction of Cr ions and form a dense film © 2022. The Authors. Published by ESG (***). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://***/licenses/by/4.0/)

关键词： Ammonium formate Deep eutectic solvents Eis analysis

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