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Accession Number
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DE2012-1052160
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Title
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High-Pressure Atomic Force Microscope for Imaging in Supercritical Carbon Dioxide.
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Publication Date
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2011
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Media Count
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8p
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Personal Author
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A. S. Lea K. G. Knauss K. M. Rosso S. R. Higgines
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Abstract
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A high-pressure atomic force microscope (AFM) that enables in situ, atomic scale measurements of topography of solid surfaces in contact with supercritical CO2 (scCO2) fluids has been developed. This apparatus overcomes the pressure limitations of the hydrothermal AFM and is designed to handle pressures up to 100 atm at temperatures up to approx. 350 K. A standard optically-based cantilever deflection detection system was chosen. When imaging in compressible supercritical fluids such as scCO2, precise control of pressure and temperature in the fluid cell is the primary technical challenge. Noise levels and imaging resolution depend on minimization of fluid density fluctuations that change the fluid refractive index and hence the laser path. We demonstrate with our apparatus in situ atomic scale imaging of a calcite (CaC03) mineral surface in scCO2; both single, monatomic steps and dynamic processes occurring on the (101 approx. 4) surface are presented. This new AFM provides unprecedented in situ access to interfacial phenomena at solid-fluid interfaces under pressure.
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Keywords
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Calcites
Carbon dioxide
Deflection
Detection
Fluid density
High pressure
Imaging resolution
Lasers
Microscopy
Minerals
Noise levels
Topography
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Source Agency
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Technical Information Center Oak Ridge Tennessee
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NTIS Subject Category
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48F - Geology & Geophysics
48A - Mineral Industries
99F - Physical & Theoretical Chemistry
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Corporate Author
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Wright State Univ., Dayton, OH. Dept. of Chemistry.
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Document Type
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Technical report
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Title Note
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N/A
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NTIS Issue Number
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1306
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Contract Number
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DE-AC02-05CH11231
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