Abstract: Tropospheric chemistry and air quality are strongly influenced by source emissions. In the western US, much attention has been focused on the air quality impacts of wildland fires; and recently, changes in air quality associated with COVID-19 shelter-in-place restrictions. Fires emit high levels of trace gases, including semi-volatile and volatile organic compounds (S/VOCs); and primary (directly emitted) particulate matter (PM). During plume evolution, S/VOCs react to form ozone (O3) and secondary PM, thereby degrading air quality downwind.
Abstract: Ambient aerosol particles derived from environmental sources (e.g., sea spray aerosol) and biological sources (e.g., respiratory aerosol) are commonly complex, aqueous organic-inorganic mixtures. Accurately predicting the properties of these particles is important for understanding air quality, climate, and public health. Despite the importance of organic-inorganic aerosol, their physical properties remain uncertain.
X-ray science has undergone a revolution in the past decade. More than 50 years after the demonstration of the visible laser, it is finally possible to routinely generate laser-like beams spanning the extreme ultraviolet to the soft X-ray region. Large- and small-scale coherent X-ray sources, including high harmonic generation (HHG) and X-ray free electron lasers (XFELs) have enabled a broad range of applications.
Abstract: We review the concepts of temporal modes (TMs) in quantum optics, highlighting Roy Glauber's crucial and historic contributions to their development, and their growing importance in quantum information science. TMs are orthogonal sets of wave packets that can be used to represent a multimode light field. They are temporal counterparts to transverse spatial modes of light and play analogous roles - decomposing multimode light into the most natural basis for isolating statistically independent degrees of freedom.
Economic challenges continue to hamper the adoption of biobased polymers as alternatives to petroleum-based plastics. Generally, renewable polymers are too expensive due to the inherent variability in biobased feedstocks and the significant separation steps required to make purified monomer streams. Here, we demonstrate that materials with reproducible thermal and mechanical characteristics can be synthesized in a controlled and predictable manner from batches of monomers with complex and somewhat variable compositions, such as minimally processed bio-oils obtained from depolymerized lign
An electron that multiphoton ionizes in a gas is immediately subject to the light’s electric field that will control its short-term future. As a result of this control, we can use a gas of atoms or molecules to produce intense VUV or soft X-ray beams by forcing the electron to recollide and recombine with its parent ion. Since we can precisely control the infrared beam that creates the radiation, we can also synthesize attosecond soft X-ray pulses – pulses that are the shortest controlled events ever systematically produced (50-attoseconds). Such pulses, when applied to materials, allow