Michael K. Crawford

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In this study we used pinfish (Lagodon rhomboides) in field experiments to examine linkages between intertidal saltmarsh and adjacent subtidal habitats. Pinfish are more than twice as abundant in intertidal marshes adjacent to seagrass beds than in those adjacent to the unvegetated subtidal bottom. Movement of pinfish between the marsh edge and the adjacent(More)
Relay systems in rigid endoscopes can compensate for aberrations in the objective and the eyepiece. Five classes of rigid relay systems are examined: conventional; glass Hopkins; plastic lens, glass-rod Hopkins; modified Hopkins; and gradient index. First-order theory, including achromatization, is developed for these systems. Design results are presented,(More)
Water-based immersion lithography using ArF illumination is able to provide optical solutions as far as the 45-nm node, but is not able to achieve the 38-or 32-nm nodes as currently defined. Achieving these lithographic nodes will require new, higher refractive index fluids to replace the water used in first-generation immersion systems. We have developed a(More)
The design ofan organic material satisfying all ofthe requirements for a single layer photolithography resist at 157 nm is a formidable challenge. All known resists used for optical lithography at 193 nm or longer wavelengths are too highly absorbing at 157 nm to be used at film thicknesses greater than-9O nm. Our goal has been to identify potential, new(More)
Photolithography at 157 nm requires development of new photoresists that are highly transparent at this wavelength. Transparent fluoropolymer platforms have been identified which also possess other materials properties required for chemically amplified imaging and aqueous development. Polymers of tetrafluoroethylene (TFE), a fluoroalcohol-substituted(More)
Twenty-two tricyclo[4.2.1.0 2,5 ]non-7-ene (TCN) or 3-oxatricyclononene monomers, having fluorinated or nonfluorinated substituents on the four-membered rings, were prepared by cycloaddition reactions of functionalized olefins with norbornadiene or quadricyclane. Radical polymerizations with tetrafluoroethylene (TFE) and/or TFE and acrylates provided(More)
The effect of nanoparticles (NP) on chain dimensions in polymer melts has been the source of considerable theoretical and experimental controversy. We exploit our ability to ensure a spatially uniform dispersion of 13 nm silica NPs miscible in polystyrene melts, together with neutron scattering, x-ray scattering, and transmission electron microscopy, to(More)
Implementation of 157 nm lithography using single-layer photoresists will require the development of resists with sufficiently high transparency in the vacuum ultraviolet to permit high resolution imaging using films approximately 200 nm thick. One of the more promising approaches to this objective involves the use of fluoropolymers as the base resins in(More)
The oxygen isotope effect on the superconducting transition temperature (alpha(o)) varies as a function of x in La2-xSrxCuO(4) and La2-xBaxCuO(4), with the maximum alpha(o) values (alpha(o) >/= 0.5) found for x near 0.12. This unusual x dependence implies that the isotope effect is influenced by proximity to the Abma --> P4(2)/ncm structural phase(More)
Novel norbornene and [4.2.1.0 2,5 ]tricyclononene monomers bearing two hexafluoro-2-propanol substituents are polymerized with tetrafluoroethylene in solution, giving amorphous, largely alternating copolymers. The norbornene copolymer shows excellent transparency at 157 nm and a dissolution rate in aqueous tetramethylammonium hydroxide that is 100 000 times(More)