Designing for child resilience

This short case study describes the design and initial feedback of a color-changing “mood lamp” that allows children to make informed decisions about risk-taking behavior on the internet. Such a device is a case study of an attempt to improve resilience amongst unsupervised children on the internet: an important goal in child protection studies

Indium oxide diffusion barriers for Al/Si metallizations

Indium oxide (In2O3) films were prepared by reactive rf sputtering of an In target in O2/Ar plasma. We have investigated the application of these films as diffusion barriers in Si/In2O3/Al and Si/TiSi2.3/In2O3/Al metallizations. Scanning transmission electron microscopy together with energy dispersive analysis of x ray of cross-sectional Si/In2O3/Al specimens, and electrical measurements on shallow n + -p junction diodes were used to evaluate the diffusion barrier capability of In2O3 films. We find that 100-nm-thick In2O3 layers prevent the intermixing between Al and Si in Si/In2O3/Al contacts up to 650°C for 30 min, which makes this material one of the best thin-film diffusion barriers on record between Al and Si. (The Si-Al eutectic temperature is 577°C, Al melts at 660°C.) When a contacting layer of titanium silicide is incorporated to form a Si/TiSi2.3/In2O3/Al metallization structure, the thermal stability of the contact drops to 600°C for 30 min heat treatment

2017 Intern Experience [at] Neil A. Armstrong Flight Research Center

These detailed individual abstracts are being included in the summer 2017 abstract book, demonstrating the knowledge learned during the summer 2017 AFRC STEM program

Frequency-Dependent Sternheimer Linear-Response Formalism for Strongly Coupled Light–Matter Systems

The rapid progress in quantum-optical experiments, especially in the field of cavity quantum electrodynamics and nanoplasmonics, allows one to substantially modify and control chemical and physical properties of atoms, molecules, and solids by strongly coupling to the quantized field. Alongside such experimental advances has been the recent development of ab initio approaches such as quantum electrodynamical density-functional theory (QEDFT), which is capable of describing these strongly coupled systems from first principles. To investigate response properties of relatively large systems coupled to a wide range of photon modes, ab initio methods that scale well with system size become relevant. In light of this, we extend the linear-response Sternheimer approach within the framework of QEDFT to efficiently compute excited-state properties of strongly coupled light–matter systems. Using this method, we capture features of strong light–matter coupling both in the dispersion and absorption properties of a molecular system strongly coupled to the modes of a cavity. We exemplify the efficiency of the Sternheimer approach by coupling the matter system to the continuum of an electromagnetic field. We observe changes in the spectral features of the coupled system as Lorentzian line shapes turn into Fano resonances when the molecule interacts strongly with the continuum of modes. This work provides an alternative approach for computing efficiently excited-state properties of large molecular systems interacting with the quantized electromagnetic field

Spectral Characteristics of the 1960 Tsunami at Crescent City, CA

Spectral characteristics of sea level fluctuations during the May 1960 Chilean Earthquake tsunami are investigated using digitized strip chart recordings from two docks within Crescent City Harbor. Peaks in sea level spectra at the two docks near 10-3 Hz and near 2.1 x10-3 Hz correspond to the two lowest frequency harbor modes, occurring above the frequency band most strongly excited by the tsunami. Tidal modulation of harbor spectral structure at very short periods is observed. Theoretical estimates of shelf edge wave resonant modes fall within the frequency band strongly excited by the tsunami, in contrast to modeled edge waves from a seismic event near Cape Mendocino that show no evidence of the reflection necessary for a strong shelf resonance. This suggests that heightened susceptibility of sea level (but not necessarily currents) at Crescent City to tsunami is not due primarily to either harbor or shelf resonances