171 research outputs found
Оценка экологической опасности рассеивания газопылевого облака при массовых взрывах в карьерах
Heteroanion
(HA) moieties have a key role in templating of heteropolyoxometalate
(HPA) architectures, but clusters templated by two different templates
are rarely reported. Herein, we show how a cross-shaped HPA-based
architecture can self-sort the HA templates by pairing two different
guests into a divacant {XYW<sub>15</sub>O<sub>54</sub>} building block,
with four of these building block units being linked together to complete
the cross-shaped architecture. We exploited this observation to incorporate
HA templates into well-defined positions within the clusters, leading
to the isolation of a collection of mixed-HA templated cross-shaped
polyanions [(XYW<sub>15</sub>O<sub>54</sub>)<sub>4</sub>(WO<sub>2</sub>)<sub>4</sub>]<sup>32–/36–</sup> (X = H–P, Y
= Se, Te, As). The template positions have been unambiguously determined
by single crystal X-ray diffraction, NMR spectroscopy, and high-resolution
electrospray ionization mass spectrometry; these studies demonstrated
that the mixed template containing HPA clusters are the preferred
products which crystallize from the solution. Theoretical studies
using DFT calculations suggest that the selective self-sorting originates
from the coordination of the template in solution. The cross-shaped
polyoxometalate clusters are redox-active, and the ability of molecules
to accept electrons is slightly modulated by the HA incorporated as
shown by differential pulse voltammetry experiments. These results
indicate that the cross-shaped HPAs can be used to select templates
from solution, and themselves have interesting geometries, which will
be useful in developing functional molecular architectures based upon
HPAs with well-defined structures and electronic properties
From chemical gardens to chemobrionics
Chemical gardens are perhaps the best example in chemistry of a
self-organizing nonequilibrium process that creates complex
structures. Many different chemical systems and materials can
form these self-assembling structures, which span at least 8
orders of magnitude in size, from nanometers to meters. Key to
this marvel is the self-propagation under fluid advection of
reaction zones forming semipermeable precipitation membranes
that maintain steep concentration gradients, with osmosis and
buoyancy as the driving forces for fluid flow. Chemical gardens
have been studied from the alchemists onward, but now in the
21st century we are beginning to understand how they can lead
us to a new domain of self-organized structures of semipermeable
membranes and amorphous as well as polycrystalline solids
produced at the interface of chemistry, fluid dynamics, and
materials science. We propose to call this emerging field
chemobrionics
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtubes
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtube
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtubes
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtube
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtubes
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtube
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtubes
Real-Time Direction Control of Self Fabricating Polyoxometalate-Based Microtube
An Accelerated Method for Investigating Spectral Properties of Dynamically Evolving Nanostructures
The discrete-dipole approximation (DDA) is widely applied
to study
the spectral properties of plasmonic nanostructures. However, the
high computational cost limits the application of DDA in static geometries,
making it impractical for investigating spectral properties during
structural transformations. Here we developed an efficient method
to simulate spectra of dynamically evolving structures by formulating
an iterative calculation process based on the rank-one decomposition
of matrices and DDA. By representing structural transformation as
the change of dipoles and their properties, the updated polarizations
can be computed efficiently. The improvement in computational efficiency
was benchmarked, demonstrating up to several hundred times acceleration
for a system comprising ca. 4000 dipoles. The rank-one decomposition
accelerated DDA method (RD-DDA) can be used directly to investigate
the optical properties of nanostructural transformations defined by
atomic- or continuum-scale processes, which is essential for understanding
the growth mechanisms of nanoparticles and algorithm-driven structural
optimization toward enhanced optical properties
A Bio-Inspired, Small Molecule Electron-Coupled-Proton Buffer for Decoupling the Half-Reactions of Electrolytic Water Splitting
Electron-coupled-proton buffers (ECPBs)
allow H2 and
O2 evolution to be separated from each other in time during
the electrolysis of water. Natural photosynthetic systems achieve
an analogous feat during water splitting and employ a range of intermediate
redox mediators such as quinone derivatives to aid this process. Drawing
on this natural example, we show that a low molecular weight quinone
derivative is capable of decoupling H2 evolution from O2 evolution at scale during electrochemical water splitting.
This work could significantly lower the cost of ECPBs, paving the
way for their more widespread adoption in water splitting
An Accelerated Method for Investigating Spectral Properties of Dynamically Evolving Nanostructures
The discrete-dipole approximation (DDA) is widely applied
to study
the spectral properties of plasmonic nanostructures. However, the
high computational cost limits the application of DDA in static geometries,
making it impractical for investigating spectral properties during
structural transformations. Here we developed an efficient method
to simulate spectra of dynamically evolving structures by formulating
an iterative calculation process based on the rank-one decomposition
of matrices and DDA. By representing structural transformation as
the change of dipoles and their properties, the updated polarizations
can be computed efficiently. The improvement in computational efficiency
was benchmarked, demonstrating up to several hundred times acceleration
for a system comprising ca. 4000 dipoles. The rank-one decomposition
accelerated DDA method (RD-DDA) can be used directly to investigate
the optical properties of nanostructural transformations defined by
atomic- or continuum-scale processes, which is essential for understanding
the growth mechanisms of nanoparticles and algorithm-driven structural
optimization toward enhanced optical properties
An Accelerated Method for Investigating Spectral Properties of Dynamically Evolving Nanostructures
The discrete-dipole approximation (DDA) is widely applied
to study
the spectral properties of plasmonic nanostructures. However, the
high computational cost limits the application of DDA in static geometries,
making it impractical for investigating spectral properties during
structural transformations. Here we developed an efficient method
to simulate spectra of dynamically evolving structures by formulating
an iterative calculation process based on the rank-one decomposition
of matrices and DDA. By representing structural transformation as
the change of dipoles and their properties, the updated polarizations
can be computed efficiently. The improvement in computational efficiency
was benchmarked, demonstrating up to several hundred times acceleration
for a system comprising ca. 4000 dipoles. The rank-one decomposition
accelerated DDA method (RD-DDA) can be used directly to investigate
the optical properties of nanostructural transformations defined by
atomic- or continuum-scale processes, which is essential for understanding
the growth mechanisms of nanoparticles and algorithm-driven structural
optimization toward enhanced optical properties
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