Waveguide effective plasmonics with structure dispersion

Plasmonic phenomena on the surface between metal and dielectric have received extensive attention, and have boosted a series of exciting techniques. Plasmonics describes the interaction between light and electronics and shows great potential in nanophotonics, optoelectronic devices, quantum physics, and surface-enhanced spectroscopy, etc. However, plasmonic phenomena are always suffering from the inherent loss issue of plasmonic materials at optical frequency, which has restricted further applications of plasmonics. In this review, we focus on the technique of waveguide effective plasmonics, which is a feasible low-loss realization of plasmonic metamaterials in lower frequency based on the structural dispersion. This review provides the underlying physics of the waveguide effective plasmonics and its applications varying from classical plasmonic concepts to novel effective plasmonic devices. Finally, we make a brief discussion on the direction of future researches and a prospect of the potential applications.

Preparation and characterization of self-cleaning cotton fabric loaded with self-dispersive and reactive biphasic TiO2

In this article, amino functionalized TiO2 (TiO2/KH550) was obtained in a mild reaction between 3-aminopropyltriethoxysilane and TiO2 with the aid of concentrated ammonia solution. 4-(4,6-dichloro-1,3,5-triazine-2-yl) amino) sodium benzenesulfonate (SAT) was synthesized and characterized by 1H NMR and fourier transform infrared spectroscopy (FT-IR). Self-dispersive and reactive TiO2 (TiO2/KH550/SAT) was prepared by nucleophile substitution reaction between TiO2/KH550 and SAT. Finally, cotton fabrics loaded with different amounts of TiO2/KH550/SAT were achieved by pad-dry-cure method. The chemical structure, dispersion and thermal performance of TiO2, TiO2/KH550 and TiO2/KH550/SAT were investigated by FT-IR, zeta potential and thermogravimetric analysis (TG). The crystalline phase, morphology, chemical composition and optical absorption property of cotton fabrics were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Moreover, the anti-ultraviolet, self-cleaning and washing fastness properties of cotton fabrics were investigated. It has been found that TiO2/KH550/SAT demonstrated excellent dispersion stability in aqueous even after standing for a month. Cotton fabrics loaded with TiO2/KH550/SAT possessed adorable anti-ultraviolet performance, highly efficient and durable self-cleaning activity as well as appreciable washing fastness property. The mechanism and possible reactions for the preparation of self-cleaning cotton fabrics loaded with TiO2/KH550/SAT were proposed.

IMPACT OF INDENTOR SLIDING VELOCITY AND LOADING REPETITION FACTOR ON SHEAR STRAIN AND STRUCTURE DISPERSION IN NANOSTRUCTURING BURNISHING

The article probes into a relationship of the shear strain intensity and the shear strain rate in the surface layer and the sliding velocity of a spherical indentor and its loading repetition factor. It brings forward an experimental procedure to evaluate the shear strain intensity and rate by analyzing the geometrical parameters of the bulge of plastically edged metal and the thickness of the shifted layer relative to different sliding velocities and feed rates.

New Findings on Multilayer Silicene on Si(111)√3×√3R30°–Ag Template

We report new findings on multilayer silicene grown on Si(111)√3 × √3 R30°–Ag template, after the recent first compelling experimental evidence of its synthesis. Low-energy electron diffraction, reflection high-energy electron diffraction, and energy-dispersive grazing incidence X-ray diffraction measurements were performed to show up the fingerprints of √3 × √3 multilayer silicene. Angle-resolved photoemission spectroscopy displayed new features in the second surface Brillouin zone, attributed to the multilayer silicene on Si(111)√3 × √3 R30°–Ag. Band-structure dispersion theoretical calculations performed on a model of three honeycomb stacked layers, silicene grown on Si(111)√3 × √3 R30°-Ag surface confirm the experimental results.

Floristic and structure of the arboral community of a regenerating fragment of Atlantic Forest, Igarassu, Pernambuco, Brazil

Understanding secondary forest structure and functioning is essential for future planning of effective use and/or recompositioning of such areas. The secondary succession process is influenced by the characteristics of componente species, their interaction with other species and with abiotic components. Thus, the objective of the current study was to evaluate the vegetation structure, dispersion syndromes and pollination of a secondary forest fragment with 5 years of regeneration in the Atlantic Forest landscape of Pernambuco, northern Brazil. A total of 30 permanent 10 x 10 m plots with 10 m separations were used for canopy sampling (i.e., all woody individuals with stem diameter at 1.30 m (DBH) greater than 5 cm. Floristic composition analysis recorded 32 species from 21 families. Absolute density was 150 individuals with basal area of 4.787 m² ha-1, and the Shannon-Weaver index (H ‘) was 2.960. The family with the highest number of species was Melastomataceae, while those with greatest abundance were Malpighiaceae (26) and Cecropiaceae (14). Species with the highest Importance Values included Byrsonima sericea (49.28%), Cecropia pachystachya (38.49%) and Bowdichia virgilioides (37.19%). The predominant tree species dispersal syndrome was zoochory (72 species), and the predominant pollination syndrome was melitophilia. Arboreal individuals were mostly recorded in the initial diameter and height classes, indicating that the study area is in the initial stage of succession.

EXCITON INSULATOR STATES IN MATERIALS WITH ‘MEXICAN HAT’ BAND STRUCTURE DISPERSION AND IN GRAPHENE

In the paper a theoretical study the both the quantized energies of excitonic states and their wave functions in grapheneand in materials with "Mexican hat" band structure dispersion as well as in zinc-blende GaN is presented. An integral twodimensionalSchrödinger equation of the electron-hole pairing for a particles with electron-hole symmetry of reflection isexactly solved. The solutions of Schrödinger equation in momentum space in studied materials by projection the twodimensionalspace of momentum on the three-dimensional sphere are found exactly. We analytically solve an integral twodimensionalSchrödinger equation of the electron-hole pairing for particles with electron-hole symmetry of reflection. Instudied materials the electron-hole pairing leads to the exciton insulator states. Quantized spectral series and lightabsorption rates of the excitonic states which distribute in valence cone are found exactly. If the electron and hole areseparated, their energy is higher than if they are paired. The particle-hole symmetry of Dirac equation of layered materialsallows perfect pairing between electron Fermi sphere and hole Fermi sphere in the valence cone and conduction cone andhence driving the Cooper instability. The solutions of Coulomb problem of electron-hole pair does not depend from a widthof band gap of graphene. It means the absolute compliance with the cyclic geometry of diagrams at justification of theequation of motion for a microscopic dipole of graphene where >1 s r . The absorption spectrums for the zinc-blendeGaN/(Al,Ga)N quantum well as well as for the zinc-blende bulk GaN are presented. Comparison with availableexperimental data shows good agreement.