A5007661356- Astro and Planetary Science
- Planetary Science and Exploration
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Isotope Analysis in Ecology
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Graphene research and applications
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Spectroscopy and Laser Applications
- Geological and Geochemical Analysis
- Plasmonic and Surface Plasmon Research
- Space Exploration and Technology
- Catalytic Processes in Materials Science
- Spectroscopy Techniques in Biomedical and Chemical Research
- Geochemistry and Geologic Mapping
- Maritime Transport Emissions and Efficiency
- Near-Field Optical Microscopy
- Field-Flow Fractionation Techniques
- Hydrocarbon exploration and reservoir analysis
- Radioactive contamination and transfer
- Vehicle emissions and performance
- Nuclear reactor physics and engineering
California State University, San Marcos
2013-2025
University of Twente
2021
Benemérita Universidad Autónoma de Puebla
2009-2019
University of California, San Diego
2008-2015
Yale University
2011
Scripps Institution of Oceanography
2010
Universidad de Alcalá
2009
Lawrence Livermore National Laboratory
2006
The Open University
2006
University of Washington
2006
Nanoimaged Polaritons Engineered heterostructures consisting of thin, weakly bound layers can exhibit many attractive electronic properties. Dai et al. (p. 1125 ) used infrared nanoimaging on the surface hexagonal boron nitride crystals to detect phonon polaritons, collective modes that originate in coupling photons optical phonons. The findings reveal dependence polariton wavelength and dispersion thickness material down just a few atomic layers.
The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. preliminary examination these samples shows that the nonvolatile portion is an unequilibrated assortment materials have both presolar solar system origin. contains abundance silicate grains are much larger than predictions interstellar grain models, many high-temperature minerals appear formed in inner regions nebula. Their presence a proves formation included...
We report on infrared (IR) nanoscopy of 2D plasmon excitations Dirac fermions in graphene. This is achieved by confining mid-IR radiation at the apex a nanoscale tip: an approach yielding two orders magnitude increase value in-plane component incident wavevector q compared to free space propagation. At these high wavevectors, found dramatically enhance near-field interaction with surface phonons SiO2 substrate. Our data augmented detailed modeling establish graphene as new medium supporting...
Samples of the carbonaceous asteroid Ryugu were brought to Earth by Hayabusa2 spacecraft. We analyzed 17 samples measuring 1 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent formed in outer Solar System. The contain low abundances materials at high temperatures, such as chondrules and calcium- aluminum-rich inclusions. rich phyllosilicates carbonates, which through aqueous alteration reactions temperature, pH,...
Abstract Evaporation or freezing of water-rich fluids with dilute concentrations dissolved salts can produce brines, as observed in closed basins on Earth 1 and detected by remote sensing icy bodies the outer Solar System 2,3 . The mineralogical evolution these brines is well understood regard to terrestrial environments 4 , but poorly constrained for extraterrestrial systems owing a lack direct sampling. Here we report occurrence salt minerals samples asteroid (101955) Bennu returned...
Organic matter in meteorites reveals clues about early Solar System chemistry and the origin of molecules important to life, but terrestrial exposure complicates interpretation. Samples returned from B-type asteroid Bennu by Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer mission enabled us study pristine carbonaceous astromaterial without uncontrolled Earth's biosphere. Here we show that samples are volatile rich, with more carbon, nitrogen ammonia than...
Particles emanating from comet 81P/Wild 2 collided with the Stardust spacecraft at 6.1 kilometers per second, producing hypervelocity impact features on collector surfaces that were returned to Earth. The morphologies of these surprisingly diverse created by particles varying dense mineral grains loosely bound, polymineralic aggregates ranging tens nanometers hundreds micrometers in size. cumulative size distribution Wild dust is shallower than Halley, yet steeper Grigg-Skjellerup.
Ship emissions contribute significantly to gaseous and particulate pollution worldwide. To better understand the impact of ship on air quality, measurements size-resolved chemistry individual particles in were made at Port Los Angeles using real-time, single-particle mass spectrometry. plumes identified through a combination position information gases aerosol site 500 m from center main shipping channel Angeles. Single containing mixtures organic carbon, vanadium, sulfate (OC-V-sulfate)...
Near-field infrared spectroscopy by elastic scattering of light from a probe tip resolves optical contrasts in materials at dramatically subwavelength scales across broad energy range, with the demonstrated capacity for chemical identification nanoscale. However, current models probe-sample near-field interactions still cannot provide sufficiently quantitatively interpretation measured contrasts, especially case supporting strong surface phonons. We present model derived basic principles and...
Abstract— The cometary tray of the NASA Stardust spacecraft's aerogel collector was examined to study dust captured during 2004 flyby comet 81P/Wild 2. An optical scan entire surface revealed 256 impact features in (width >100 μm). Twenty blocks (out a total 132) were removed from for higher resolution and 186 tracks observed (track length >50 μm width >8 classified into three types based on their morphology. Laboratory calibrations conducted that reproduced all types. This work...
Pump-probe spectroscopy is central for exploring ultrafast dynamics of fundamental excitations, collective modes and energy transfer processes. Typically carried out using conventional diffraction-limited optics, pump-probe experiments inherently average over local chemical, compositional, electronic inhomogeneities. Here we circumvent this deficiency introduce infrared with ~20 nm spatial resolution, far below the diffraction limit, which accomplished a scattering scanning near-field...
Historically, the physical chemistry of isotope effects and precise measurements in samples from nature have provided information on processes that could not been obtained otherwise. With discovery a mass-independent isotopic fractionation during formation ozone, new chemical basis for required development. Combined theoretical experimental developments broadened this understanding extended range systems where these unique occur. Simultaneously, application to an extensive both terrestrial...
Abstract— The capture of 81P/Wild 2 cometary particles in aerogel with a well‐defined impact velocity (6.1 km s −1 ) has provided wealth data concerning the composition Jupiter‐family comets. To interpret this we must understand processes aerogel. A major category tracks are those bulbous cavities lined particle fragments. We present new model to account for production these “turnip”‐shaped cavities. uses thermodynamic approach order likely expansion vapors from rich volatile species. Volume...
Sulfate (SO 4 ) and its precursors are significant components of the atmosphere, with both natural anthropogenic sources. Recently, our triple-isotope ( 16 O, 17 18 O) measurements atmospheric sulfate have provided specific insights into oxidation pathways leading to sulfate, important implications for models sulfur cycle global climate change. Using similar isotopic aerosol in a polluted marine boundary layer (MBL) primary p -SO sampled directly from ship stack, we quantify amount found...
A recent earthquake and the subsequent tsunami have extensively damaged Fukushima nuclear power plant, releasing harmful radiation into environment. Despite obvious implication for human health surrounding ecology, there are no quantitative estimates of neutron flux leakage during weeks following earthquake. Here, using measurements radioactive (35)S contained in sulfate aerosols SO(2) gas at a coastal site La Jolla, California, we show that nearly 4 × 10(11) neutrons per m(2) leaked plant...
The debate of life on Mars centers around the source globular, micrometer-sized mineral carbonates in ALH84001 meteorite; consequently, identification Martian processes that form is critical. This paper reports a previously undescribed carbonate formation process occurs Earth and, likely, Mars. We identified terrestrial aerosols possess excess 17 O (0.4–3.9‰). unique O-isotopic composition mechanistically describes atmospheric heterogeneous chemical reaction aerosol surfaces. Concomitant...
To clarify the presence of lymphocytic choriomeningitis virus (LCMV) in Spain, we examined blood and tissue specimens from 866 small mammals. LCMV RNA was detected 3 694 wood mice (Apodemus sylvaticus). Phylogenetic analyses suggest that strains constitute a new evolutionary lineage. antibodies were 4 10 rodent species tested.
Abstract We analyzed an asteroid Ryugu sample returned to Earth by JAXA's Hayabusa2 mission using nanoIR, SEM, and TEM microscopy. identified multiple distinct carbon reservoirs within the phyllosilicate matrix demonstrate infrared spectral affinities for some of insoluble organic matter (IOM). studies samples have allowed us better understand interrelationship between crystallographic orientations phyllosilicates secondary minerals such as carbonate, sulfide, apatite. Transport elements...
Anthropogenic activities, dominated by emissions of sulfur dioxide (SO 2 ), have perturbed the global (S) cycle. Uncertainties in timescales S transport and chemistry atmosphere lead to uncertainties predicted impact emissions. Measurements cosmogenic 35 may potentially be used resolve existing photochemical chemical transformation environment. The lack a simple, effective, highly sensitive technique measure activity samples with low activities explain scarcity published measurements. We...
The oldest solids formed in the solar system, calcium–aluminum inclusions, are 16O-enriched compared to chondrules, asteroids, Earth, and Mars. Based on preliminary measurements of wind by Genesis, Sun also appears be 16O-enriched. This distribution oxygen isotopes system cannot reconciled via conventional mass-dependent isotopic fractionation processes instead require existence and/or production distinct 16O-depleted reservoirs early system. origin these is unknown, although several...