The 6d electrons of Ac atom involved in excited transitions induce a strong CT-SERS enhancement which can be tuned by changing the conformation of pyridine-Ac@Au7 complexes.
We present a microfluidics system with Ag nanodot arrays as the enhancement substrate for multiplexed SERS detection of low-concentration mixtures of thiram and adenine.
A novel high-swirl reactor ANJEVOC-CP
(annular jet vortex chamber
for combustion pyrolysis) was designed for producing high-value chemicals
such as alkynes and olefins from natural gas. In such a single-stage
nonpremixed combustion pyrolysis process, methane and oxygen streams
are spirally conveyed into the ANJEVOC-CP burner creating high-swirl
annular jets around an internal recirculation zone, leading to a compact
nonpremixed fuel-rich flame for methane pyrolysis. Computational fluid
dynamics (CFD) simulations of this reactor concept indicate the potential
for high alkyne yield due to the rapid mixing of combustion products
with CH4 under a broad range of operating conditions; and
this was experimentally verified in a lab-scale reactor under a subset
of conditions (enriched oxygen concentration from 21% to 60% by volume
and equivalence ratio from 1.28 to 2.4). The experimental studies
showed 10.4 mol % carbon-based overall acetylene yield with up to
60% enriched oxygen molar concentration in the oxidizer stream in
the lab-scale experiment. The CFD simulation predictions of the fluid
flow and reactor performance are in reasonable agreement with the
experimental observations and provided complementary insights into
the respective roles of high swirl, species and thermal transport,
and reaction kinetics that contribute to the high performance. Using
a reduced GRI-Mech 3.0 and a modified GRI mechanism, the model predicted
20–25% overall acetylene yield at the same scale with higher
enriched oxygen concentration. Considering the fact that excessive
heat loss due to the high surface-area-to-volume ratio in the small
lab-scale prototype with inert gas dilution could degrade performance,
ANJEVOC-CP is a promising methane conversion technology for acetylene
production and deserves further investigation at larger scales.
In
the studies of surface-enhanced Raman scattering (SERS), it
is considered to be a key point to couple the surface plasmons of
metallic nanomaterials and structures to resonate, which can assist
higher SERS signal enhancement. This paper is to explore a strategy
for plasmon resonating based on the leaky mode resonance (LMR) of
a polyimide (PI) optical waveguide (OWG), for the purpose of achieving
the highly sensitive evanescent field-excited SERS. PI was chosen
to build the waveguide layer due to its merits of exhibiting small
extinction coefficients in the natural light frequency, low cost,
high flexibility, easy fabrication, and almost no Raman spectral interference.
The OWG configuration guarantees a high harvesting efficiency for
the incident light. Ag nanoparticles were assembled on top of the
OWG layer as plasmonic antennas to provide a large scattering cross
section based on the coupling of the LMR and metal plasmon resonance
(MPR), which supports highly efficient SERS radiation and being conducive
to the far-field collection. The LMR-MPR coupling can facilitate stronger
local electromagnetic field around the side surfaces of the Ag nanoparticles,
which is favorable to the adsorption of analytes. The PI OWG-coupled
MPR structure can realize the integration of SERS excitation light
paths and elements, which is not only a valuable SERS enhancement
configuration but also a promising technique for the surface and thin
film analysis.
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