Douglas E. Wolfe

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Hard X-ray phase-contrast imaging characterizes the electron density distribution in an object without the need for radiation absorption. The power of phase contrast to resolve subtle changes, such as those in soft tissue structures, lies in its ability to detect minute refractive bending of X-rays. Here we report a far-field, two-arm interferometer based(More)
We introduce a new spectral method for the retrieval of optical thickness and effective radius from cloud transmittance that relies on the spectral slope of the normalized transmittance between 1565 nm and 1634 nm, and on cloud transmittance at a visible wavelength. The standard dual-wavelength technique, which is traditionally used in reflectance-based(More)
The shallow mixing depth and vertical stratifica-tion of the lowest levels of the atmosphere at night has implications for the chemistry of nitrogen oxides emitted from the surface. Here we report vertical profiles of NO 3 , N 2 O 5 and O 3 measured from in-situ instruments on a movable carriage on a 300 m tower. The study offers high-resolution (<1 m)(More)
The shallow mixing depth and vertical stratification of the lowest levels of the atmosphere at night has implications for the chemistry of nitrogen oxides emitted from the surface. Here we report vertical profiles of NO 3 , N 2 O 5 and O 3 measured from in-situ instruments on a movable carriage on a 300 m tower. The study offers high-resolution 5 (<1 m)(More)
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