Search

Efforts to map atomic-scale chemistry at low doses with minimal noise using electron microscopes are fundamentally limited by inelastic interactions. Here, fused multi-modal electron microscopy offers high signal-to-noise ratio (SNR) recovery of material chemistry at nano- and atomic-resolution by coupling correlated information encoded within both elastic scattering (high-angle annular dark-field (HAADF)) and inelastic spectroscopic signals (electron energy loss (EELS) or energy-dispersive x-ray (EDX)). By linking these simultaneously acquired signals, or modalities, the chemical distribution within nanomaterials can be imaged at significantly lower doses with existing detector hardware. In many cases, the dose requirements can be reduced by over one order of magnitude. This high SNR recovery of chemistry is tested against simulated and experimental atomic resolution data of heterogeneous nanomaterials.

Efforts to map atomic-scale chemistry at low doses with minimal noise using electron microscopes are fundamentally limited by inelastic interactions. Here, fused multi-modal electron microscopy offers high signal-to-noise ratio (SNR) recovery of material chemistry at nano- and atomic-resolution by coupling correlated information encoded within both elastic scattering (high-angle annular dark-field (HAADF)) and inelastic spectroscopic signals (electron energy loss (EELS) or energy-dispersive x-ray (EDX)). By linking these simultaneously acquired signals, or modalities, the chemical distribution within nanomaterials can be imaged at significantly lower doses with existing detector hardware. In many cases, the dose requirements can be reduced by over one order of magnitude. This high SNR recovery of chemistry is tested against simulated and experimental atomic resolution data of heterogeneous nanomaterials.

Ultraviolet spectra obtained with the Hubble Space Telescope of the carbon star TX Piscium (HR 9004) are presented, along with analysis providing information on its outer atmosphere, including flow and turbulent velocities, line formation mechanisms, and, Addresses: Carpenter KG, NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, CODE 681, GREENBELT, MD 20771. NASA, GODDARD SPACE FLIGHT CTR, ASTRON PROGRAMS, COMP SCI CORP, GREENBELT, MD 20771. INDIANA UNIV, DEPT ASTRON, BLOOMINGTON, IN 47405. UNIV CO

To advance our understanding of the relationship between stellar chromospheres and mass loss, which is a common property of carbon stars and other asymptotic giant branch stars, we have obtained ultraviolet spectra of the nearby N-type carbon star UU Aur, Addresses: JOHNSON HR, INDIANA UNIV, DEPT ASTRON, SWAIN W 319, BLOOMINGTON, IN 47405. WICHITA STATE UNIV, DEPT PHYS, WICHITA, KS 67208. SMITHSONIAN ASTROPHYS OBSERV, CTR ASTROPHYS, CAMBRIDGE, MA 02138. UNIV COLORADO, JILA, BOULDER, CO 80309. NASA, GODDARD