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Showing 1 to 20 of 33 for “"Hexagonal Close-Packed"”.
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Combined X-Ray and Thermal Conductivity Study of Hexagonal-Close-Packed Helium-4
Made available in DSpace on 2015-05-12T21:41:54Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 7013302.PDF: 2755643 bytes, checksum: 5c70d685e133a8e1a642b5e8cf648376 (MD5) Previous issue date: 1969
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Combined x-ray and thermal conductivity study of hexagonal-close packed helium-4
Thermal conductivity measurements made on hexagonal-close-packed helium-4 are reported for specimens whose quality and orientation were determined directly by an x-ray method. The specimens, 2.2mmin diameter by 23 mm long, were held in a nylon container. They were obtained by unidirectional growth …
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The influence of mixed hexagonal close-packed and face-centered cubic ordering on precipitation pathways and kinetics in sputtered superalloys
… (FCC) and, unexpectedly, significant amounts of hexagonal close-packed (HCP) domains. This mixed close-packed crystal structure caused the Ni-Mo-Cr alloy Haynes® 242™ to directly precipitate the stable HCP-based DOa-type Ni3Mo phase during a standard aging heat treatment. This precipitation …
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Selective Oxidation of Aluminum-Bearing Iii-V Semiconductors: Properties and Applications to Small-Volume Quantum Well Heterostructure Lasers
… lasers that are arranged in a triangular (hexagonal close-packed) lattice arrangement. The disks are closely spaced (11-$\mu$m center-to-center spacing) such that they are strongly coupled. As a result of the coupling of the disks, the photonic lattice exhibits laser operation in bands of …
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Scanning Probe Microscopy Study of Molecular Self Assembly Behavior on Graphene Two-dimensional Material
… planar sheet of carbon atoms densely packed in a honeycomb crystal lattice, has grabbed appreciable attention due to its exceptional electronic, mechanical and optical properties. Chemical functionalization schemes are needed to integrate graphene with the different materials required …
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The State-Based Peridynamic Lattice Model
… number of particles that are arranged by a hexagonal close-packed lattice. We present a SPLM linear-elasticity and plasticity model that has been derived from the classical model. We then conclude this thesis with several benchmark examples and a look forward to future research.
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Development of novel bio/nano interfaces for materials science and biomedical applications
… types of nanomaterials, including self-assembled hexagonal close-packed arrays and nanoparticles with greatly enhanced surface plasmonic properties. Multivalent peptide display on MS2 VLPs greatly enhances their affinity for target cells (e.g. hepatocellular carcinoma), providing the specificity …
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Changes in the cation ordering of layered O3 Lix̳Ni₀.₅Mn₀.₅O₂ during electrochemical cycling to high voltages
… reflections consistent with the 01 phase with hexagonal-close-packed oxygen array were detected in the 5.3 V but not in the 4.5 V charged sample. Therefore, electron diffraction evidence was found to support the concept of Ni migration from the Li to the transition metal layer, and to confirm …
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Fabrication of Organized Anisotropic Materials via Evaporative Self-Assembly
… of gold nanotriangles (AuNTs) into hexagonal close-packed superlattices by slow evaporation and includes a morphological comparison of the crystallization habits of gold nanorods (AuNRs) and AuNTs. Chapter 3 discusses the use of a passive foaming system constructed from commercially …
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Overcoming the limits of strain-induced martensitic transformation in metastable face-centered cubic alloys
… of strain-induced face-centered cubic (FCC) to hexagonal close-packed (HCP) martensitic transformation, a plastic deformation-driven stacking fault formation concept is also assessed, which contributes to latent strain hardening while mitigating the formation of blocky HCP-martensite. Future …
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Heat transfer model for the ignition of metal powder on a heated filament
… heated filament. The coating is modeled using a hexagonal close packed geometry and the heat transfer equations are derived for one dimensional heat flow. An Arrhenius type expression is used to describe the chemical reaction leading to ignition with the pre-exponent as an adjustable parameter. …
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Solute transport in magnesium and their uncertainty quantification using density functional theory and green function approach
… and vacancy-mediated solute transport in the hexagonal close-packed Mg. We utilize density functional theory calculations to determine the energies of interstitials and solute-vacancy configurations, which inform our diffusion model. The diffusion of light elemental solutes B, C, N, and O is …
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Magnesium nanoplasmonics: synthesis, characterisation, and applications
… Mg nanoarrays sustaining LSPRs. Next, Mg’s hexagonal close packed crystal structure, unique among plasmonic metals, leads to various Mg crystal shapes, including twinned structures, cubes, and spheroids, which are probed for their near-field optical properties both experimentally and …
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The Mossbauer effect in iron under very high pressure
… transformation of part of the iron source to the hexagonal-close-packed high pressure phase. With increasing pressure this line becomes more intense and the split spectrum disappears although the transformation is sluggish. From the absence of splitting and from the observed linewidth we conclude …
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Stress Corrosion Cracking of a Transformation Induced Plasticity Fe39Mn20CO20Cr15Si5Al1 High Entropy Alloy
… from γ (face-centered cubic) to ɛ (hexagonal closed pack) phase. The TRIP Fe39Mn20Co20Cr15Si5Al1 (at. %) HEA consists of two phases: the ɛ – martensite phase (hexagonal close-packed structure) and the γ – austenite phase (face-centered cubic), with phase fractions of ~97% and ~3%, …
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Study of the training effect in exchange bias using the domain state model
… structures such as body-centered cubic and hexagonal-close packed, were investigated as in these structures the coupling between the ferromagnet and the antiferromagnet increases. In these structures, in addition to the interface roughness, the enhance coupling is shown to give rise to …
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Physically based multiscale-viscoplastic model for metals and steel alloys: theory and computation
… (body centered cubic, face centered cubic and hexagonal close-packed) and steel alloys are derived in this work for this purpose. We adopt a multi-scale, hierarchical thermodynamic consistent framework to construct the material constitutive relations for the rate-dependent behavior. The concept …
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Phase Transformation and Mechanical Behavior of Laser Powder Bed Fusion (LPBF) Manufactured Co-28Cr-6Mo
… face-centered-cubic (FCC) structure to ϵ-phase hexagonal-close packed (HCP) structure varies in speed and sensitivity to phase transformation aging temperature depending on the print setting. Phase transition time reached a minimum for all the samples at around a Tp = 850 or 860◦C. The …
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The second and third order elastic constants of magnesium
… Because magnesium exists in the non-primitive hexagonal close-packed structure, a macroscopic strain gives rise to inter1attice displacements, i.e., internal strains. The internal strain parameter has been calculated by requiring the energy density of the strained state to be a minimum. It was …
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Three Dimensional Characterization of Deformation Twins Using Synchrotron X-Ray Diffraction
Hexagonal closed-packed (HCP) metals have been extensively used in various industrial sectors, eg, zirconium in nuclear industry, magnesium in transportation industry, and titanium in aerospace industry. Understanding deformation mechanisms of HCP metals is crucial for developing predictive models …
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