The complete mitochondrial genome (mitogenome) of Cerura menciana (Lepidoptera: Notodontidae) was sequenced and analyzed in this study. The mitogenome is a circular molecule of 15,369 bp, containing 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes and a -rich region. The positive skew (0.031) indicated that more As than Ts were present. All PCGs were initiated by ATN codons, except for the cytochrome c oxidase subunit 1 (cox1) gene, which was initiated by . Two of the 13 PCGs contained the incomplete termination codon or , while the others were terminated with the stop codon . The -rich region was 372 bp in length and consisted of an ‘’ motif followed by an 18 bp poly- stretch, a microsatellite-like ()8 and a poly- element upstream of the trnM gene. Results examining codon usage indicated that Asn, Ile, Leu2, Lys, Tyr and Phe were the six most frequently occurring amino acids, while Cys was the rarest. Phylogenetic relationships, analyzed based on the nucleotide sequences of the 13 PCGs from other insect mitogenomes, confirmed that C. menciana belongs to the Notodontidae family.

A simple metamaterial absorber is proposed to achieve near-perfect absorption in visible and near-infrared wavelengths. The absorber is composed of metal-dielectric-metal (MIM) three-layer structure. The materials of these three-layer structures are Au, SiO 2 , and Au. The top metal structure of the absorber is composed of hollow three-dimensional metal rings regularly arranged periodically. The results show that the high absorption efficiency at a specific wavelength is mainly due to the resonance of the Fabry-Perot effect (FP) in the intermediate layer of the dielectric medium, resulting in the resonance light being trapped in the middle layer, thus improving the absorption efficiency. The almost perfect multiband absorption, which is independent of polarization angle and insensitivity of incident angle, lends the absorber great application prospects for filtering and optoelectronics.Nanomaterials 2020, 10, 488 2 of 10 to their absorption band, absorption capacity, absorption principle, and absorption spectrum [8][9][10][11][12][13][14]. For example, the Salisbury screen is mainly used in the military to reduce the reflection of radar detectors by canceling the interference of reflected microwaves by the reflection layer [15]. The same principle can be used in optical frequencies to design an anti-reflective film on a camera lens or glass. For another example, a pyramid-shaped structure can increase the number of reflections and scatter in the structure by matching the impedance of free space, thus increasing the absorption efficiency [16].Since the concept of the perfect absorber was introduced in 2008, the research on superstructure electromagnetic material absorbers has shown exponential growth year by year [17][18][19][20]. From the initial microwave frequency band to terahertz [20,21], infrared [22,23], and visible frequency band [24][25][26][27], a large number of studies have been conducted, and absorption bandwidth also includes single-frequency absorption, dual-frequency absorption, multi-frequency absorption, and broadband absorption [28][29][30][31][32][33]. Compared with the traditional absorption materials, the advantage of the superstructure material absorber lies in the structure size, arrangement, and different materials selected to form the dual-frequency, multi-frequency, or dual-band absorber [34][35][36]. The structure size is small and the processing method is simple, which is conducive to the integration in the period surface [37][38][39]. The structure or quantity can be flexibly adjusted to achieve different absorption purposes. Due to the variety of absorbers, the absorbers have a different applicable wavelengths, bandwidths, structure characteristics, adjustable abilities, and absorption principles. In this paper, a multi-band metamaterial absorber in the visible light range is designed from the perspective of the absorption frequency band. By changing the structure size of the absorber and the metal structure on the surface, the absorber can achieve a broader tolerance range for polar...

The combination of critical coupling and coupled mode theory in this study elevated the absorption performance of a graphene-based absorber in the near-infrared band, achieving perfect absorption in the double bands (98.96% and 98.22%), owing to the guided mode resonance (the coupling of the leak mode and guided mode under the condition of phase matching, which revealed 100% transmission or reflection efficiency in the wavelet band), and a third high-efficiency absorption (91.34%) emerged. During the evaluation of the single-structure, cross-circle-shaped absorber via simulation and theoretical analysis, the cross-circle shaped absorber assumed a conspicuous preponderance through exploring the correlation between absorption and tunable parameters (period, geometric measure, and incident angle of the cross-circle absorber), and by briefly analyzing the quality factors and universal applicability. Hence, the cross-circle resonance structure provides novel potential for the design of a dual-band unpatterned graphene perfect absorber in the near-infrared band, and possesses practical application significance in photoelectric detectors, modulators, optical switching, and numerous other photoelectric devices.

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In this paper, a theoretical simulation based on a finite-difference time-domain method (FDTD) shows that the solar absorber can reach ultra-broadband and high-efficiency by refractory metals titanium (Ti) and titanium nitride (TiN). In the absorption spectrum of double-size cross-shaped absorber, the absorption bandwidth of more than 90% is 1182 nm (415.648-1597.39 nm). Through the analysis of the field distribution, we know the physical mechanism is the combined action of propagating plasmon resonance and local surface plasmon resonance. After that, the paper has a discussion about the influence of different structure parameters, polarization angle and angle of incident light on the absorptivity of the absorber. At last, the absorption spectrum of the absorber under the standard spectrum of solar radiance Air Mass 1.5 (AM1.5) is studied. The absorber we proposed can be used in solar energy absorber, thermal photovoltaics, hot-electron devices and so on.