The mechanical properties of core–shell bimetallic composite nanowires, forming the bases of nanoporous metallic foams, have been investigated and compared with pure metal nanowires using molecular dynamics simulations. In the current study, pure copper and gold nanowires under uniaxial loading were tested at room temperature and compared to composite nanowires of the same materials (core) with a nickel coating (shell). The core radius ranged from 1 to 15 nm, and the shell thickness ranged from 0.1 to 5 nm. The tension strain was performed along the [001] direction under room temperature. Both coherent and semi-coherent composite nanowires were studied, and the effect of coating layer thickness was investigated. The strengthening mechanisms of the core–shell structures due to the presence of the two different types of interfaces were investigated for various nickel thicknesses. The atomistic simulation results revealed that the addition of the nickel shell strengthens the structure when the layer thickness exceeds a critical value.
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Intra-Data Center 120Gbaud/DP-16QAM Self-Homodyne Coherent Links with Simplified Coherent DSP
Abstract:
The first 120Gbaud-based C-band self-homodyne 800Gb/s coherent links using low-latency FEC are experimentally demonstrated. A minimum coherent DSP is proposed to compensate fiber dispersion, phase mismatch between signal and local oscillator, and transceiver I-Q impairments.
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- Award ID(s):
- 1821819
- NSF-PAR ID:
- 10378726
- Date Published:
- Journal Name:
- 2022 Optical Fiber Communications Conference and Exhibition (OFC).
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract: The first 120Gbaud-based C-band self-homodyne 800Gb/s coherent links using lowlatency FEC are experimentally demonstrated. A minimum coherent DSP is proposed to compensate fiber dispersion, phase mismatch between signal and local oscillator, and transceiver I-Q impairments. © 2022 The Author(s)more » « less
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Abstract Integrated quadrant analysis is a novel technique to identify and to characterize the trajectory and strength of turbulent coherent structures in the atmospheric surface layer. By integrating the three-dimensional velocity field characterized by traditional quadrant analysis with respect to time, the trajectory history of individual coherent structures can be preserved with Eulerian turbulence measurements. We develop a method to identify the ejection phase of coherent structures based on turbulence kinetic energy (TKE). Identifying coherent structures within a time series using TKE performs better than identifying them with the streamwise and vertical velocity components because some coherent structures are dominated by the cross-stream velocity component as they pass the sensor. By combining this identification method with the integrated quadrant analysis, one can animate or plot the trajectory of individual coherent structures from high-frequency velocity measurements. This procedure links a coherent ejection with the subsequent sweep and quiescent period in time to visualize and quantify the strength and the duration of a coherent structure. We develop and verify the method of integrated quadrant analysis with data from two field studies: the Eclipse Boundary Layer Experiment (EBLE) in Corvallis, Oregon in August 2017 (grass field) and the Vertical Cherry Array Experiment (VACE) in Linden, California in November 2019 (cherry orchard). The combined TKE identification method and integrated quadrant analysis are promising additions to conditional sampling techniques and coherent structure characterization because the identify coherent structures and couple the sweep and ejection components in space. In an orchard (VACE), integrated quadrant analysis verifies each coherent structure is dominated by a sweep. Conversely, above the roughness sublayer (EBLE), each coherent structure is dominated by an ejection.
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Turbulent wakes are often characterized by dominant coherent structures over disparate scales. Dynamics of their behaviour can be attributed to interscale energy dynamics and triadic interactions. We develop a methodology to quantify the dynamics of kinetic energy of specific scales. Coherent motions are characterized by the triple decomposition and used to define mean, coherent and random velocity. Specific scales of coherent structures are identified through dynamic mode decomposition, whereby the total coherent velocity is separated into a set of velocities classified by frequency. The coherent kinetic energy of a specific scale is defined by a frequency triad of scale-specific velocities. Equations for the balance of scale-specific coherent kinetic energy are derived to interpret interscale dynamics. The methodology is demonstrated on three wake flows: (i)
${Re}=175$ ${Re}=3900$
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
