Henry H Wu

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We calculate first-principles interaction energies between substitutional solutes and oxygen interstitials in a-titanium and predict the effect of solutes on oxygen diffusion from those interactions. Interaction between 45 solutes across the periodic table and three oxygen interstitial sites are calculated with density-functional theory. The interaction(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 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)
Data-dependent jitter (DDJ) caused by lossy channels is a limiting factor in the bit rates that can be achieved reliably over serial links. This thesis explains the causes of DDJ and existing equalization techniques, then develops an asynchronous (clock-agnostic) architecture for DDJ compensation. The compensation circuit alters the transition times of a(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)
A family of local segmentation vector filters for color image noise suppression and detail preservation is proposed. Most state-of-the-art filters alleviate impulse noise well but tend to destroy thin lines, edges and fine image details. The proposed filters facilitate local segmentation to preserve image structures and noise suppression. First the K-VMF is(More)