Magnetic surface polariton (MSP) is a surface electromagnetic mode which is the dual of surface plasmon polaritons and has some peculiar properties. In the present paper, based on this surface mode, we design a 2D Luneburg lens for the manipulation of magnetic surface polariton. MSP-based devices may be realized using magnetic metamaterials or composite magnetic materials.
The family Miridae is one of the most species-rich families of insects.To better understand the diversity and evolution of mirids, we determined the mitogenome of Lygus pratenszs and re-sequenced the mitogenomes of four mirids (i.e.Apolygus lucorum, Adelphocoris suturalis, Ade.fasciaticollis and Ade.lineolatus).We performed a comparative analysis for 15 mitogenomic sequences representing 11 species of five genera within Miridae and evaluated the potential of these mitochondrial genes as molecular markers.Our results showed that the general mitogenomic features (gene content, gene arrangement, base composition and codon usage) were well conserved among these mirids.Four proteincoding genes (PCGs) (cox1, cox3, nad1 and nad3) had no length variability, where nad5 showed the largest size variation; no intraspecific length variation was found in PCGs.Two PCGs (nad4 and nad5) showed relatively high substitution rates at the nucleotide and amino acid levels, where cox1 had the lowest substitution rate.The Ka/Ks values for all PCGs were far lower than one (< 0.59), but the Ka/Ks values of cox1-barcode sequences were always larger than 1 (1.34 -15.20), indicating that the 658 bp sequences of cox1 may be not the appropriate marker due to positive selection or selection relaxation.Phylogenetic analyses based on two concatenated mitogenomic datasets consistently supported the relationship of Nesidiocoris + (Trigonotylus + (Adelphocoris + (Apolygus + Lygus))), as revealed by nad4, nad5, rrnL and the combined 22 transfer RNA genes (tRNAs), respectively.Taken sequence length, substitution rate and phylogenetic signal together, the individual genes (nad4, nad5 and rrnL) and the combined 22 tRNAs could been used as potential molecular markers for Miridae at various taxonomic levels.Our results suggest that it is essential to evaluate and select suitable markers for different taxa groups when performing phylogenetic, population genetic and species identification studies.
Hypopterygium obstusum is described and illustrated as a new moss species from Guizhou, southwest China. The new species is mainly characterized by its medium to large size, irregularly pinnate to bipinnate branching, absence of axial cavities, octostichous phyllotaxis, and isophyllous foliation in stipe and basal rachis, indistinct border in all leaves and amphigastria, acute to obtuse leaf apex in lateral frond leaves, and presence of gemmae. Phylogenetic analysis resolved H. obstusum sister to H. flavolimbatum based on plastid rps4, trnG, trnL–F, and nuclear internal transcribed spacer (ITS) sequences. A detailed morphological description, an illustration of the new species, and a key to all Chinese species of this genus are provided.
A series of model probes with different sizes and polarity, such as ammonia, pyridine, and thiophene, have been used to gain insight into the influence mechanisms of extraframework aluminum (EFAl) species on the properties of Bro̷nsted acid sites (BASs) in HY zeolites by periodic DFT calculation. EFAl species enhance the intrinsic strength of BAS in HY zeolites similar to the generally accepted results. However, the presence of EFAl species induces a significant deviation of a correlation between the adsorption energies of the probe molecules and the changes in intrinsic acidity characterized by DPE. These results demonstrate that EFAl species exert the additional forces (dispersion forces) on the probe molecules adsorbed on the BAS. In this work, a principal finding is by using a weaker polarity and right fit size molecule (that of thiophene in this work) as a probe can reveal the synergistic mechanisms between the EFAl species and the BAS.
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