Large-scale and tunable transparent displays based on silver nanoparticles metasurface.

We report a transparent display based on a metasurface of silver nanoparticles (Ag NPs), consisting of a transparent substrate and a layer of Ag NPs deposited by a dielectric film. The Ag NPs metasurface is prepared by a simple and direct annealing process. It presents a deep transmission valley at the wavelength ofλ= 468 nm and enables desired transparent display by projecting the monochromatic image onto the metasurface. We also demonstrate that the formed Ag NPs can be approximated as truncated nanospheres, which have obvious directional scattering properties, and can radiate most of the scattered energy into the backward hemisphere with a relatively large angular beamwidth (the full width at half maximum of the scattered intensity) of ∼90°. Therefore, the fabricated displays possess wide viewing angles and high brightness characteristics. Additionally, the transmission modes can be red-shifted to the wavelength ofλ= 527 nm by controlling the thickness of the deposited dielectric film. This approach using traditional thin film deposition and moderate annealing processing techniques enables simple, low-cost, and scalable fabrication in large areas for transparent displays.

Comparison of Needle-Warming Moxibustion and Other Physical Therapies for Lumbar Disc Herniation: A Meta-analysis.

Background: Needle-warming moxibustion (NWM) demonstrates a controversial effect on lumbar disc herniation (LDH). This study is aimed at comparing the efficacy of NWM and conventional acupuncture or other physical therapies on LDH through a meta-analysis. Methods: Potentially eligible literatures were retrieved and screened from electronic databases. The subject of the literature was a comparison of NWM and conventional acupuncture or other physical therapies for LDH. The methodological quality was evaluated by the Jadad scale. The chi-square test was used for the heterogeneity test. Subgroup analysis was used to explore the source of heterogeneity. Risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI) was used to describe the effect size. The publication bias was evaluated by Egger's test. Results: The effective rate of NWM in the treatment of LDH was significantly higher than that of conventional acupuncture (RR = 1.27, 95%CI [1.18, 1.36], P < 0.00001) and lumbar traction (RR = 1.12, 95%CI [1.06, 1.18], P < 0.0001) There was no significant difference in the effective rate between NWM and electric acupuncture for LDH (RR = 1.06, 95%CI [0.98, 1.14], P = 0.17). VAS of LDH patients treated with NWM was lower than conventional acupuncture (MD = -1.51, 95%CI [-1.70, -1.31], P < 0.00001) and lumbar traction (MD = -2.64, 95%CI [-2.79, -2.49], P < 0.00001) but statistically insignificant with electric acupuncture (MD = -0.31, 95%CI [-0.72, 0.09], P = 0.13). JOA scores of LDH patients treated with NWM were higher than those with conventional acupuncture (MD = 2.24, 95%CI [1.04, 3.45], P = 0.0003) and lumbar traction (MD = 10.76, 95%CI [10.45, 11.07], P < 0.00001) but statistically insignificant with electric acupuncture (MD = 0.25, 95%CI [-0.95, 1.45], P = 0.69). The long-term effective rate of NWM on LDH was higher than that of conventional acupuncture (MD = 3.13, 95%CI[2.12, 4.61], P < 0.00001). In this study, no heterogeneity (P > 0.10, I 2 < 50%) and publication bias (P > 0.05) among the literature were noted. Conclusion: The effect of NWM on LDH was superior to traction therapy and conventional acupuncture therapy, but similar to electric acupuncture for LDH. High-quality randomized controlled trials were still needed to confirm the results.

Two-Dimensional Planar BGe Monolayer as an Anode Material for Sodium-Ion Batteries.

Using first-principles swarm intelligence structure prediction computations, we explore a fully planar BGe monolayer with unique mechanical and electrical properties. Theoretical calculations reveal that a free-standing BGe monolayer has excellent stability, which is confirmed by the cohesive energy (compared to experimentally synthetic borophene and germanene monolayers), phonon modes (no imaginary frequencies appeared in the phonon spectrum), ab initio molecular dynamics (AIMD) simulations (no broken bonds and geometric reconstructions), and mechanical stability criteria. The metallic feature of the BGe monolayer can be maintained after absorbing different numbers of Na atoms, ensuring good electronic conductivity during the charge/discharge process. The calculated migration energy barrier, open-circuit voltage, and theoretical specific capacity of the BGe monolayer are much better than those of some other two-dimensional (2D) materials. These findings render the BGe monolayer a potential candidate for reversible Na-ion battery anode materials with desirable performance.

Two-dimensional Ga2O2 monolayer with tunable band gap and high hole mobility.

By means of density functional theory and unbiased structure search computations, we systematically investigated the stability and electronic properties of a new Ga2O2 monolayer. The phonon spectra and ab initio molecular dynamics simulations show that the Ga2O2 monolayer is dynamically and thermally stable. Moreover, it also shows superior open-air stability. In particular, the Ga2O2 monolayer is an indirect semiconductor with a wide band gap of 2.752 eV and high hole mobility of 4720 cm2 V-1 s-1. Its band gap can be tuned flexibly in a large range by applied strain and layer control. It exhibits high absorption coefficients (>105 cm-1) in the ultraviolet region. The combined novel electronic properties of the Ga2O2 monolayer imply that it is a highly promising material for future applications in electronics and optoelectronics.

Guided mode caused by silicon nanopillar array for light emission enhancement in color-converting LED.

Plasmonic metallic nanostructures have been demonstrated an effective way to enhance the light emission efficiency in LEDs. Here, we propose a design of white LEDs that combining dielectric silicon nanopillar array in the color-converting layer. By investigating theoretically the guided mode caused by the nanopillar array-waveguide system, we demonstrate that the silicon nanopillar arrays enable larger near-field enhancement and more efficient photons emission property than the plasmonic counterparts. These performances make the silicon nanopillar arrays have potential application in light converter for efficient white LEDs. We also show that the guided mode can be controlled by changing the period of nanopillar grating and the thickness of polymer layer. More significant performance can be achieved by further optimizing the shape and size of the silicon nanoparticles. Compared with the square nanoparticle arrays, the hexagonal nanopillar arrays are demonstrated to have larger field enhancement and emission enhancement. Our research is expected to give insights into the design and optimization of the solid-state lighting systems by using silicon nanostructures, and the all-dielectric metamaterials for gaining or lasing devices.