Henry H. Wu

Learn More
How impurity atoms move through a crystal is a fundamental and recurrent question in materials. The previous models of oxygen diffusion in titanium relied on interstitial lattice sites that were recently found to be unstable--leaving no consistent picture of the diffusion pathways. Using first-principles quantum-mechanical methods, we find three oxygen(More)
Lattice mismatch of Cu on Ag͑111͒ produces fast diffusion for " magic sizes " of islands. A size-and shape-dependent reptation mechanism is responsible for low diffusion barriers. Initiating the reptation mechanism requires a suitable island shape, not just magic sizes. Shape determines the dominant diffusion mechanism and leads to multiple clearly(More)
Introduction: Acquiring a 3D volume in a short scan time is a high-priority goal of many MR imaging applications. This is especially true for time-sensitive studies, such as magnetization-prepared imaging and dynamic imaging, where the signal is in transition. Fast imaging trajectories, such as under-sampled 3DPR or 3D stack-of-spirals, can provide a great(More)
We present the results of a joint experimental and theoretical study on the absolute photoabsorption cross sections from the ground state leading to resonance structures between the Mg ϩ 3p 2 P and Mg ϩ 4s 2 S thresholds. The absolute cross sections are determined by measuring the light attenuation through a heatpipe using the synchrotron radiation. The(More)
We demonstrate automated generation of diffusion databases from high-throughput density functional theory (DFT) calculations. A total of more than 230 dilute solute diffusion systems in Mg, Al, Cu, Ni, Pd, and Pt host lattices have been determined using multi-frequency diffusion models. We apply a correction method for solute diffusion in alloys using(More)
A binary embedded-atom method (EAM) potential is optimized for Cu on Ag(1 1 1) by fitting to ab initio data. The fitting database consists of DFT calculations of Cu monomers and dimers on Ag(1 1 1), specifically their relative energies, adatom heights, and dimer separations. We start from the Mishin Cu–Ag EAM potential and first modify the Cu–Ag pair(More)
MEMS gyroscopes are used to detect rotation rates and have enabled a variety of motion-based technologies in a range of industries. They are composed of micro-machined poly-silicon structures that resonate and deflect when a rotation is experienced. The topic of this thesis surrounds a system architecture to optimize the performance of a gyroscope. The MEMS(More)
  • 1