473 research outputs found

    <saponifiable and nonsaponifiable soxlet and cold solvent extracts of a number of soils, recent sediment cores from the pacific ocean, and the orgueil carbonaceous meteorite< semiannual progress report, nov. 1964 - may 1965

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    Saponifiable and nonsaponifiable soxlet and cold solvent extracts of soil, carbonaceous meteorite, and sedimentary rocks studied by thin layer chromatography and spectroscop

    Space bandwidth product of conventional Fourier Transforming Systems

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    Cataloged from PDF version of article.It is shown that the space-bandwidth product of conventional "2f" Fourier transforming configurations can be increased without bound by increasing the diameter D and focal length fof the lens simultaneously to Docf 3/4. This results in spacebandwidth product growth ocf ~/2 and accompanying system linear extent growth ocf ~/4. These are derived by considering the validity of the Fresnel approximation, the thin lens approximation, and the effects of aberrations

    Scaling of diffractive and refractive lenses for optical computing and interconnections

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    Cataloged from PDF version of article.We discuss both numerically and analytically how the space-bandwidth product and the information density of lenses scale as functions of their diameter and f-number over many orders of magnitude. This information may be useful for the design of optical computing and interconnection systems. For diffractive lenses, cost is defined as the number of resolution elements the lithographic production system must have; the relationship of this quantity to the space-bandwidth product and information density is also given

    A review of evidence for biological material in meteorites

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    Carbonaceous chondrite - mineral and inorganic chemical composition and biological material in meteorite

    Learned holographic light transport: Invited

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    Computer-generated holography algorithms often fall short in matching simulations with results from a physical holographic display.Our work addresses this mismatch by learning the holographic light transport in holographic displays. Using a camera and a holographic display, we capture the image reconstructions of optimized holograms that rely on ideal simulations to generate a dataset. Inspired by the ideal simulations, we learn a complex-valued convolution kernel that can propagate given holograms to captured photographs in our dataset. Our method can dramatically improve simulation accuracy and image quality in holographic displays while paving the way for physically informed learning approaches

    The optics of an autostereoscopic multiview display

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    An autostereoscopic head-tracked back projection display that uses an RGB laser illumination source and a fast light engine is described. Images are horizontally scanned columns controlled by a spatial light modulator that directs two or more images in the directions of the apposite viewers’ eyes

    Hydrologic Transport of Dissolved Inorganic Carbon and Its Control on Chemical Weathering

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    Chemical weathering is one of the major processes interacting with climate and tectonics to form clays, supply nutrients to soil microorganisms and plants, and sequester atmospheric CO2. Hydrology and dissolution kinetics have been emphasized as factors controlling chemical weathering rates. However, the interaction between hydrology and transport of dissolved inorganic carbon (DIC) in controlling weathering has received less attention. In this paper, we present an analytical model that couples subsurface water and chemical molar balance equations to analyze the roles of hydrology and DIC transport on chemical weathering. The balance equations form a dynamical system that fully determines the dynamics of the weathering zone chemistry as forced by the transport of DIC. The model is formulated specifically for the silicate mineral albite, but it can be extended to other minerals, and is studied as a function of percolation rate and water transit time. Three weathering regimes are elucidated. For very small or large values of transit time, the weathering is limited by reaction kinetics or transport, respectively. For intermediate values, the system is transport controlled and is sensitive to transit time. We apply the model to a series of watersheds for which we estimate transit times and identify the type of weathering regime. The results suggest that hydrologic transport of DIC may be as important as reaction kinetics and dilution in determining chemical weathering rates

    Improvements in Mass Spectrometers for the Measurement of Small Differences in Isotope Abundance Ratios

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    A Nier-type mass spectrometer and its associated electronic units have been constructed for the purpose of measuring small variations in the abundances of oxygen of mass 18 and of carbon of mass 13 in carbon dioxide, and of oxygen of mass 18 in oxygen gas, to an accuracy of ±0.01 percent of the abundance of these isotopes.The electronic units of the necessary stability for this degree of accuracy are described. A gas feed system is described which permits fast alternate introduction of the sample of gas to be analyzed and a standard gas into the mass spectrometer. All measurements of the variation in the abundance of the oxygen and carbon isotopes are made with reference to a standard

    Laser Scanning 3D Display with Dynamic Exit Pupil

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    A novel auto-stereoscopic 3D display system that forms dynamic exit pupils with the aid of a head-tracker is described Different views are displayed using time-multiplexing. Visible lasers, beam combiner, shaping and scanning optics and exit pupil control optics are discussed. It is estimated that 100 fL display brightness is achievable with about 3W per color of R, G and, B lasers
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