The Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign was designed to improve understanding of orographic cloud life cycles in relation to surrounding atmospheric thermodynamic, flow, and aerosol conditions. The deployment to the Sierras de Córdoba range in north-central Argentina was chosen because of very frequent cumulus congestus, deep convection initiation, and mesoscale convective organization uniquely observable from a fixed site. The C-band Scanning Atmospheric Radiation Measurement (ARM) Precipitation Radar was deployed for the first time with over 50 ARM Mobile Facility atmospheric state, surface, aerosol, radiation, cloud, and precipitation instruments between October 2018 and April 2019. An intensive observing period (IOP) coincident with the RELAMPAGO field campaign was held between 1 November and 15 December during which 22 flights were performed by the ARM Gulfstream-1 aircraft.A multitude of atmospheric processes and cloud conditions were observed over the 7-month campaign, including: numerous orographic cumulus and stratocumulus events; new particle formation and growth producing high aerosol concentrations; drizzle formation in fog and shallow liquid clouds; very low aerosol conditions following wet deposition in heavy rainfall; initiation of ice in congestus clouds across a range of temperatures; extreme deep convection reaching 21-km altitudes; and organization of intense, hail-containing supercells and mesoscale convective systems. These comprehensive datasets include many of the first ever collected in this region and provide new opportunities to study orographic cloud evolution and interactions with meteorological conditions, aerosols, surface conditions, and radiation in mountainous terrain.
Transition-metal
selenides (TMSs) as electrode materials for supercapacitors
(SCs) are suffering from low rate capacities and poor cyclic stability
due to their easy aggregation and structural instability over charge/discharge
cycles. Herein, reduced graphene oxide (rGO) nanosheet-wrapped hollow
cobalt selenide (CoSe2) nanocubes are synthesized using
a sacrificial-template method combined with a selenization treatment.
In such nanocomposites, hollow CoSe2 nanocubes with porous
shells are featured by abundant electroactive sites, easy ion diffusion,
and enough buffering space. More importantly, the wrapping of rGO
nanosheets around hollow CoSe2 nanocubes not only endows
the nanocomposites with higher electrical conductivity but also restrains
the aggregation of hollow CoSe2 nanocubes as well as maintains
the structural stability during cycles. Consequently, the synthesized
hollow CoSe2@rGO nanocomposites demonstrate a specific
capacity of up to 856 C g–1 at 2 A g–1, 76% capacity retention at 20 A g–1, and 95% capacity
retention over 5000 cycles at 10 A g–1. Moreover,
an asymmetric supercapacitor cell with hollow CoSe2@rGO
nanocomposites as the positive electrode achieves an energy density
of 53.0 W h kg–1 at a power density of 800 W kg–1, suggesting a great potential for their practical
applications. This work showcases a feasible approach to engineer
hollow TMS–graphene nanocomposites as electrode materials for
SCs.
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