69 research outputs found
Computational Study on the Microscopic Adsorption Characteristics of Linear Alkylbenzene Sulfonates with Different Chain Lengths on Anthracite Surface
In order to explore the influence of different lengths of hydrophobic carbon chains on the diffusion characteristics of surfactants on the surface of anthracite, six linear alkyl benzene sulfonates with different hydrophobic carbon chain lengths were selected (mC, m = 8, 10, 12, 14, 16, 18; m represents the numbers of carbon atoms in the hydrophobic carbon chain), and molecular dynamics (MD) simulations were adopted. Models of surfactant-anthracite, surfactant-graphite layer, and water-surfactant-anthracite were constructed. After analyzing a series of properties such as adsorption energy, diffusion coefficient, radial distribution function (RDF), and hydrophobic tail order parameters, it was found that 12C had the highest adsorption strength on the surface of anthracite; the reason was that 12C had the highest degree of aggregation near the oxygen-containing functional groups on the surface of anthracite. Further studies had found that the hydrophobic tail chain of 12C had the strongest isotropy. The study fills the gap in the systematic study of the diffusion characteristics of linear alkylbenzene sulfonates (LAS) with different chain lengths on the surface of anthracite, enriches and develops the basic theory of coal wettability, and also provides technical ideas for the design of new surfactants and new dust suppression agents
Structural Color 3D Printing By Shrinking Photonic Crystals
The rings, spots and stripes found on some butterflies, Pachyrhynchus
weevils, and many chameleons are notable examples of natural organisms
employing photonic crystals to produce colorful patterns. Despite advances in
nanotechnology, we still lack the ability to print arbitrary colors and shapes
in all three dimensions at this microscopic length scale. Commercial nanoscale
3D printers based on two-photon polymerization are incapable of patterning
photonic crystal structures with the requisite ~300 nm lattice constant to
achieve photonic stopbands/ bandgaps in the visible spectrum and generate
colors. Here, we introduce a means to produce 3D-printed photonic crystals with
a 5x reduction in lattice constants (periodicity as small as 280 nm), achieving
sub-100-nm features with a full range of colors. The reliability of this
process enables us to engineer the bandstructures of woodpile photonic crystals
that match experiments, showing that observed colors can be attributed to
either slow light modes or stopbands. With these lattice structures as 3D color
volumetric elements (voxels), we printed 3D microscopic scale objects,
including the first multi-color microscopic model of the Eiffel Tower measuring
only 39-microns tall with a color pixel size of 1.45 microns. The technology to
print 3D structures in color at the microscopic scale promises the direct
patterning and integration of spectrally selective devices, such as photonic
crystal-based color filters, onto free-form optical elements and curved
surfaces
Silicon Nanoantenna Mix Arrays for a Trifecta of Quantum Emitter Enhancements
Dielectric nanostructures have demonstrated optical antenna effects due to
Mie resonances. Preliminary investigations on dielectric nanoantennas have been
carried out for a trifecta of enhancements, i.e., simultaneous enhancements in
absorption, emission directionality and radiative decay rates of quantum
emitters. However, these investigations are limited by fragile substrates or
low Purcell factor, which is extremely important for exciting quantum emitters
electrically. In this paper, we present a Si mix antenna array to achieve the
trifecta enhancement of ~1200 fold with a Purcell factor of ~47. The antenna
design incorporates ~10 nm gaps within which fluorescent molecules strongly
absorb the pump laser energy through a resonant mode. In the emission process,
the antenna array increases the radiative decay rates of the fluorescence
molecules via Purcell effect and provides directional emission through a
separate mode. This work could lead to novel CMOS compatible platforms for
enhancing fluorescence for biological and chemical applications.Comment: 20 pages, 4 figure
Enhancing the functional output of transplanted islets in diabetic mice using a drug-eluting scaffold
Abstract Background Islet transplantation is increasingly used in the diabetic patients to control the blood glucose level. However, the functional output of transplanted islets remains hampered due to the local inflammation, loss of islets, etc. To that end, in this study we explored to enhance the functional output of transplanted islets in diabetic mice by employing a drug-eluting scaffold with a payload of interleukin 4 (IL-4). Results According to the in vitro studies, the scaffold showed no cytotoxicity, a rapid release of IL-4 within a week and the IL-4 retained its bioactivity. During the 4-week time window after the islet transplantation, in vivo studies showed that the levels of blood insulin and C-peptide 2 in diabetic mice in the drug-eluting scaffold group significantly increased since week 2, which effectively reduced the blood glucose level. In addition, these mice demonstrated a stronger capability to withstand a rapid glucose spike as evidenced by the tolerance of sudden oral glucose challenge test result. A further mechanistic study suggested that the enhanced functional output could be attributed to the M2 polarization of macrophages as evidenced by the increase of CD163+/CD68+ macrophages in the islet tissues. A M2 polarization of macrophages is widely believed to exert an anti-inflammatory influence on local tissues, which could accelerate the resolution of local inflammation following the islet transplantation. Conclusion Our study shed a new light on the hyperglycemia management of diabetic patients following the islet transplantation
Printing Beyond sRGB Color Gamut by Mimicking Silicon Nanostructures in Free-Space
Localized optical resonances in metallic
nanostructures have been
increasingly used in color printing, demonstrating unprecedented resolution
but limited in color gamut. Here, we introduce a new nanostructure
design, which broadens the gamut while retaining print resolution.
Instead of metals, silicon nanostructures that exhibit localized magnetic
and electric dipole resonances were fabricated on a silicon substrate
coated with a Si<sub>3</sub>N<sub>4</sub> index matching layer. Index
matching allows a suppression of substrate effects, thus enabling
Kerker’s conditions to be met, that is, sharpened transitions
in the reflectance spectra leading to saturated colors. This nanostructure
design achieves a color gamut superior to sRGB, and is compatible
with CMOS processes. The presented design could enable compact high-resolution
color displays and filters, and the use of a Si<sub>3</sub>N<sub>4</sub> antireflection coating can be readily extended to designs with nanostructures
fabricated using other high-index materials
Miniaturizing Color-Sensitive Photodetectors via Hybrid Nanoantennas towards Sub-micron Dimensions
Digital camera sensors utilize color filters on photodiodes to achieve color
selectivity. As color filters and photosensitive silicon layers are separate
elements, these sensors suffer from optical cross-talk, which sets limits to
the minimum pixel size. In this paper, we report hybrid silicon-aluminum
nanostructures in the extreme limit of zero distance between color filters and
sensors. This design could essentially achieve sub micron pixel dimensions and
minimize the optical cross-talk originated from tilt illuminations. The
designed hybrid silicon-aluminum nanostructure has dual functionalities.
Crucially, it supports a hybrid Mie-plasmon resonance of magnetic dipole to
achieve the color-selective light absorption, generating electron hole pairs.
Simultaneously, the silicon-aluminum interface forms a Schottky barrier for
charge separation and photodetection. This design could potentially replace the
traditional dye based filters for camera sensors at ultra-high pixel densities
with advanced functionalities in sensing polarization and directionality, as
well as UV selectivity via interband plasmons of silicon.Comment: 32 pages, 4 Figures (main text), 7 Figures (supplementary
Enhancing the functional output of transplanted islets in diabetic mice using a drug-eluting scaffold
Gene Expression Profiles Deciphering Leaf Senescence Variation between Early- and Late-Senescence Cotton Lines
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