1,353 research outputs found
Design and analysis of electrothermal metasurfaces
Electrothermal metasurfaces have attracted extensive attention due to their
ability to dynamically control thermal infrared radiation. Although previous
studies were mainly focused on the metasurfaces with infinite unit cells, the
finite-size effect can be a critical design factor for developing thermal
metasurfaces with fast response and broad temperature uniformity in practice.
Here, we study the thermal metasurfaces consisting of gold nanorods with a
finite array size, which, with only several periods, can achieve a resonance
close to that of the infinite case. More importantly, such a small footprint
due to the finite array size results in the response time down to a nanosecond
level. Furthermore, the number of the unit cells in the direction perpendicular
to the axis of the nanorods is found to be insensitive to the resonance and
response time, thus providing a tunability in aspect ratio that can boost the
temperature uniformity in the sub-Kelvin level.Comment: 14 pages, 5 figure
Role of long non-coding RNA in the pathogenesis of diabetic retinopathy
Long non-coding RNA(LncRNA)is a class of transcript(>200 nucleotides)that do not encode proteins. It plays an important role in epigenetic regulation and gene expression at transcriptional or post transcriptional level. The abnormal expression of LncRNA may lead to various pathological processes. Diabetic retinopathy(DR)is a multifactorial disease. Recent studies have shown that many specific expressions of LncRNAs are closely related to the genesis of DR. In this review, we summarized the recent advances in the function of LncRNA, the regulatory mechanisms of LncRNA involved in the development of DR, and the related therapies
Accurate Direct Measurements of Far-Field Thermal Infrared Emission and its Dynamics
Accurate direct measurements of far-field thermal infrared emission become
increasingly important because conventional methods, relying on indirect
assessments, such as reflectance/transmittance, are inaccurate or even
unfeasible to characterize state-of-art devices with novel spectra,
directionalities, and polarizations. The direct collection of the far-field
emission from these tiny devices is also challenging because of their shrinking
footprints and uncontrollable radiation noises from their surroundings. Here,
we demonstrate a microscopic lock-in FTIR system that realizes significant
improvement in signal-to-noise ratio (SNR) by combining a microscope and a
lock-in amplifier with an FTIR. The lock-in FTIR is ultrasensitive, with a
specific detectivity 10^6 times higher than commercial ones, to overcome the
optical loss and background noise during the emission light collection. Based
on an analytical model of the signal detection process, we also explore the
combination of modulated Joule heating and global heating to fulfill the
potential of our system for noise reduction. Our findings show that, compared
to previous studies, more than 3 times lower temperatures are sufficient to
generate a measurable signal. Under a heating temperature of around 125
{\deg}C, we can achieve an SNR of about 23.7, which is far above the
true-signal-threshold (SNR of about 3.0). Furthermore, the system can respond
fast enough (up to 175kHz) to record spectral-resolved dynamics of microdevices
in the frequency domain. The measurable frequency range can be extended up to
MHz or even GHz level by a high-speed circuit model. We believe the system
together with the analytical signal processing can be beneficial for
next-generation thermal infrared material and device exploration, boosting the
applications in lighting, sensing, imaging, and energy harvesting on a small
scale.Comment: 19 pages, 4 figure
Preliminary Trial to Establish Artificial Grassland in Tibet, China
Tibet Autonomous Region with an average altitude of more than 4,000 m above sea level, altogether cover an area of 1.22 million km2, equivalent to one-eight of the total area of China. High mountains along with forests and rivers in Tibet consist of an important ecological barrier for protecting parts of inland ecosystems. Tibet is also one of the five major pastoral areas in China. The grassland in Tibet covers 0.83 million km2, but the grass is sparse and low, and with low yield in this area. There are nearly 2.8 million people in this region, while the area of arable land is less than 2.533 thousand km2. Nearly 40.5 million tons of hay are needed for about 45 million sheep units in Tibet (Yu et al., 2010), while the actual amount is less than 20 million tons (including 15 million tons per year from natural grassland, and 2~3 million tons per year from the straw of naked barley). It exacerbating the degradation of natural grassland for the contradiction between livestock and grass. Research shows that the most effective measure to maintain local economic growth, coordinated development of ecological security and curb the further degradation of the grassland in Tibet is by planting high yielding and high quality forage crops, changing the traditional way of free grazing and implementing captive feeding gradually
N,N,N′,N′-TetraÂkis(2-hyÂdroxy-5-methylÂbenzÂyl)ethane-1,2-diamine dimethylÂformamide disolvate
The title compound, C34H40N2O4·2C3H7NO, was synthesized by the Mannich condensation of ethaneÂdiamine, formaldehyde and p-cresol. In the crystal, the tetraÂphenol molÂecule is arranged around an inversion center. The molÂecule and the dimethylÂformamide solvate are linked through an O—H⋯O hydrogen bond. An intraÂmolecular O—H⋯N hydrogen bond occurs in the tetraÂphenol molÂecule, which may influence the molÂecular confomation. Futhermore, C—H⋯O and π–π stacking interÂactions [centroid–centroid distance = 3.7081 (14) Å] stabilize the crystal packing, building a three-dimensional network
Dichlorido(10,11,12,13-tetraÂhydro-4,5,9,14-tetraÂazabenzo[b]triphenylÂene)cadmium(II) hemihydrate
In the title compound, [CdCl2(C18H14N4)2]·0.5H2O, the Cd atom assumes a distorted octaÂhedral trans-CdCl2N4 geometry arising from its coordination by two N,N′-bidentate 10,11,12,13-tetraÂhydro-4,5,9,14-tetraÂazabenzo[b]triphenylÂene (TBBT) molÂecules and two chloride ions. In the crystal, π–π aromatic stacking interÂactions between adjacent TTBT rings are seen, with a centroid–centroid distance of 3.604 (3) Å. An O—H⋯Cl hydrogen bond between the half-occupied water molecule and one chloride ion also occurs
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