Self-assembled metallic nanoparticle template --- a new approach of surface nanostructuring at nanometer scale

In the present work, the formation of silver and copper nanostructures on highly oriented pyrolytic graphite (HOPG) modified with self-assembled gold nanoparticles (Au NPs) is demonstrated. Surface patterning with nanometer resolution was achieved. Different methods such as field emission scanning electron microscopy (FEGSEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) were used to illustrate a selective deposition of silver and copper on Au NPs. The mechanism of silver and copper ions reduction on Au NP with $n$-dodecanethiol coating is discussed.Comment: 6 pages, 3 figure

Effective index approximations of photonic crystal slabs: a 2-to-1-D assessment

The optical properties of slab-like photonic crystals are often discussed on the basis of effective index (EI) approximations, where a 2-D effective refractive index profile replaces the actual 3-D structure. Our aim is to assess this approximation by analogous steps that reduce finite 2-D waveguide Bragg-gratings (to be seen as sections through 3-D PC slabs and membranes) to 1-D problems, which are tractable by common transfer matrix methods. Application of the EI method is disputable in particular in cases where locally no guided modes are supported, as in the holes of a PC membrane. A variational procedure permits to derive suitable effective permittivities even in these cases. Depending on the structural properties, these values can well turn out to be lower than one, or even be negative. Both the “standard” and the variational procedures are compared with reference data, generated by a rigorous 2-D Helmholtz solver, for a series of example structures.\u

Estimate of the possibility of conducting mass spectrometric measurements of the matter of lunar surface

Electron beams studied for use in lunar soil spectrometric analysi

Did DR-CAFTA Affect the Exports of the Dominican Republic to the United States?

This article evaluates the impact the Dominican Republic and Central America Free Trade Agreement (DR-CAFTA) had on the exports of the Dominican Republic (DR) to the United States. We estimate a gravity model for the DR exports to the 109 trade partners of the country from 1990 to 2014. This model quantifies the effect of the DR-CAFTA since 2007, when the agreement was ratified, and finds that the DR-CAFTA negatively affected DR exports to the US. We conduct further analysis of factors that could explain the decline in exports, in spite of the ratification of the agreement. We find that the 2008–09 crisis was not the driver of the slowdown of DR exports to the US. The increasing competition with Central American countries and other export oriented economies, like China, in the US market seem to have the leading role in the export contraction that we find in our study

Strength diagrams of fibrous composites with unidirectional structure

The dependence of the composite strength on the volume proportion of fiber and the transfer factor is analyzed. Four types of diagrams are constructed for the strength of composites as a function of the volume proportion of fibers and the transfer factor