Double-bowl state in photonic Dirac nodal line semimetal

The past decade has seen a proliferation of topological materials for both insulators and semimetals in electronic systems and classical waves. Topological semimetals exhibit topologically protected band degeneracies, such as nodal points and nodal lines. Dirac nodal line semimetals (DNLS), which own four-fold line degeneracy, have drawn particular attention. DNLSs have been studied in electronic systems but there is no photonic DNLS. Here in this work, we provide a new mechanism, which is unique for photonic systems to investigate a stringent photonic DNLS. When truncated, the photonic DNLS exhibits double-bowl states (DBS), which comprise two sets of perpendicularly polarized surface states. In sharp contrast to nondegenerate surface states in other photonic systems, here the two sets of surface states are almost degenerate over the whole-spectrum range. The DBS and the bulk Dirac nodal ring (DNR) dispersion along the relevant directions, are experimentally resolved.

Establishment of Raman Fingerprints and Localization of Main Components of Radix Angelicas sinensis from Different Origins

In this paper, confocal micro-Raman spectrum (CMR) was used to investigate the distribution of main components (ferulic acid and nicotinic acid) in Radix Angelicae sinensis (RAS). The ferulic acid and nicotinic acid were scanned to obtain their Raman spectra of single component; the RAS from different origins were scanned to obtain the Raman spectrum of RAS, and the Raman spectrum was compared with single component. The Raman spectrum of a single component was introduced into the map review to localize ferulic acid and nicotinic acid in RAS. In the results, the RAS from different origins showed strong similarity, with obvious characteristic peaks at 120 cm–1 140 cm–1210 cm–1,480 cm–1 and 1050 cm–1. The characteristic peaks of ferulic acid are mainly concentrated in the spectrum range of 100-1100 cm1 with obvious characteristic peaks around 160 cm150 cm–1 and 1800 cm–1 while the peaks of nicotinic acid mainly concentrated in the spectrum range of 100-1100 cm–1, with obvious characteristic peaks around 120 cm–1, 140 cm–1,810 cm–1and 1050 cm–1 The red and the green color represent the locations of ferulic acid and nicotinic acid, respectively. In conclusion, CMR can be used to establish the Raman fingerprint library of RAS for a quick and accurate identify, and locate the known active components.

Microstructure and Photothermal Conversion Performance of Ti/(Mo-TiAlN)/(Mo-TiAlON)/Al2O3 Selective Absorbing Film for Non-Vacuum High-Temperature Applications

This paper aims to clarify the phase composition in each sub-layer of tandem absorber TiMoAlON film and verify its thermal stability. The deposited multilayer Ti/(Mo-TiAlN)/(Mo-TiAlON)/Al2O3 films include an infrared reflectance layer, light interference absorptive layers with different metal doping amounts, and an anti-reflectance layer. The layer thicknesses of Ti, Mo-TiAlN, Mo-TiAlON, and Al2O3 are 100, 300, 200, and 80 nm, respectively. Al content increases to 12 at.% and the ratio of N/O is nearly 0.1, which means nitride continuously changes to oxide. According to X-ray Diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) results, the diffraction peak that appears at 2θ = 40° demonstrates that Mo element aggregates in the substitutional solid solution (Ti,Al)(O,N) columnar grain. TiMoAlON films have low reflectivity in the spectrum range of 300–900 nm. When Al content is more than 10 at.%, absorptivity is almost in the spectrum range from visible to infrared, but absorptivity decreases in the ultraviolet spectrum range. When Al content is increased to 12 at.%, absorptivity α decreases by 0.05 in the experimental conditions. After baking in atmosphere at 500 °C for 8 h, the film has the highest absorptivity when doped with 2 at.% Mo. In the visible-light range, α = 0.97, and in the whole ultraviolet-visible-light near-infrared spectrum range, α = 0.94, and emissivity ε = 0.02 at room temperature and ε = 0.10 at 500 °C.

Service for determining forest taxational indicators based on automated processing of multispectral remote sensing data

The article considers a service for providing consumers with various levels of information about forest taxing indicators based on the processing of multispectral data recorded by modern domestic remote sensing spacecraft in the optical spectrum range.