Kevin G. Yager

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The change in shape inducible in some photo-reversible molecules using light can effect powerful changes to a variety of properties of a host material. This class of reversible light-switchable molecules includes molecules that photo-dimerize, such as coumarins and anthracenes; those that allow intra-molecular photo-induced bond formation, such as fulgides,(More)
Thin films of polymers containing non-linear optical chromophores based on azobenzene have been shown to respond mechanically to low power light interference, resulting in a transfer of an arbitrary optical pattern to surface relief in a single step, often well below the usual glass transition temperature. The timescale for this process is seconds to(More)
BACKGROUND Transgenesis using cardiac-specific expression has been valuable in exploring cardiac structure-function relationships. To date, cardiac-selective studies have been confined to the mouse. However, the utility of the mouse is limited in certain, possibly critical, aspects with respect to cardiovascular function. METHODS AND RESULTS To establish(More)
Organization of spherical particles into lattices is typically driven by packing considerations. Although the addition of directional binding can significantly broaden structural diversity, nanoscale implementation remains challenging. Here we investigate the assembly of clusters and lattices in which anisotropic polyhedral blocks coordinate isotropic(More)
Azobenzene polymer thin films exhibit reversible surface mass transport when irradiated with a light intensity and/or polarization gradient, although the exact mechanism remains unknown. In order to address the role of thermal effects in the surface relief grating formation process peculiar to azo polymers, a cellular automaton simulation was developed to(More)
Self-assembly of block copolymers is a powerful motif for spontaneously forming well-defined nanostructures over macroscopic areas. Yet, the inherent energy minimization criteria of self-assembly give rise to a limited library of structures; diblock copolymers naturally form spheres on a cubic lattice, hexagonally packed cylinders and alternating lamellae.(More)
Coherent X-ray scattering is an emerging technique for measuring structure at the nanoscale. Data management and analysis is becoming a bottleneck in this technique. We present an unsupervised method which can sort and cluster the scattering snapshots, uncovering patterns inherent in the data. Our algorithm operates without resorting to templates, specific(More)
Visual inspection of x-ray scattering images is a powerful technique for probing the physical structure of materials at the molecular scale. In this paper, we explore the use of deep learning to develop methods for automatically analyzing x-ray scattering images. In particular, we apply Convolutional Neural Networks and Convolutional Autoencoders for x-ray(More)
Directed self-assembly (DSA) of block copolymers is an emergent technique for nano-lithography, but is limited in the range of structures possible in a single fabrication step. Here we expand on traditional DSA chemical patterning. A blend of lamellar- and cylinder-forming block copolymers assembles on specially designed surface chemical line gratings,(More)