We propose a theoretical study of the optimization of one dimensional metal-dielectric metamaterials in order to approach -1 effective optical index. Taking into account actual values of dielectric constants of metal (silver) and dielectrics (HfO(2), GaP), and taking advantage of the dispersion relation of Bloch modes, we get a silver/HfO(2)metamaterial with suitable parameters that possesses a...

This paper presents a simple approach for forming anti-reflective film stacks on plastic substrates employing aqueous colloidal dispersions of metal oxide nanoparticles. Results demonstrate that it is possible to fabricate a polymeric thin film of continuously tunable refractive index over a wide range by loading the film with varying concentrations of metal oxide nanoparticles. Specifically, t...

The objective of the study was to determine whether long-term metal pollution affects communities of epigeal spiders (Aranea), studied at three taxonomic levels: species, genera, and families. Biodiversity was defined by three indices: the Hierarchical Richness Index (HRI), Margalef index (D(M)) and Pielou evenness index (J). In different ways the indices describe taxa richness and the distribu...

BACKGROUND Following the reintroduction of metal-on-metal articulating surfaces for total hip arthroplasty in Europe in 1988, we developed a surface arthroplasty prosthetic system using a metal-on-metal articulation. The present study describes the clinical and radiographic results of the first 400 hips treated with metal-on-metal hybrid surface arthroplasties at an average follow-up of three a...

the aim of this study was to compare the shear bond strength (sbs) of resin modified glass ionomer (rmgi) and composite resin for bonding metal and ceramic brackets.eighty-eight human premolars extracted for orthodontic purposes were divided into 4 groups (n=22). in groups 1 and 2, 22 metal and ceramic brackets were bonded using composite resin (transbond xt), respectively. twenty-two metal and...

background: heavy metal pollution in the sediment of the yellow river draws wide attention in the recent years. the yellow river wetland nature reserve of zhengzhou is one of the major wetlands of the river and located at the beginning of the lower reach. in this article, we aimed to investigate the degree and the sources of the metal pollution in the reserve. methods: metals as cu, pb, cr, cd ...

The collapse voltage of micromachined capacitive ultrasonic transducers (CMUT) depends on the size, thickness, type, and position of the metal electrode within the membrane. This paper reports the result of a finite element study of this effect. The program (ANSYS 5.7) is used to model a circular membrane on top of a Si substrate covered by a Si3N4 insulation layer. We find that the collapse vo...

Aquatic environmental deterioration is becoming a serious problem due to rapid urbanization and economic development, particularly in developing countries. As two important components of the aquatic environment, water quality and sediment pollution are widely considered to be concerns; however, they are considered separately in most cases. The relationship between water quality and sediment pol...

Waveguide-coupled silicon ring or disk resonators have been used for optical signal processing and sensing. Large-scale integration of optical devices demands continuous reduction in their footprints, and ultimately they need to be replaced by silicon-based plasmonic resonators. However, few waveguide-coupled silicon-based plasmonic resonators have been realized until now. Moreover, fluid canno...

Soil pollution by metal(loid)s resulting from rapid economic development is a major concern. Accurately estimating the spatial distribution of soil metal(loid) pollution has great significance in preventing and controlling soil pollution. In this study, 126 topsoil samples were collected in Kunshan City and the geo-accumulation index was selected as a pollution index. We used Kriging interpolat...