Early Aspects at ICSE 2007: Workshop on Aspect-Oriented Requirements Engineering and Architecture Design

The “Early Aspects @ ICSE’07” is the 11th workshop in the series of Early Aspects workshops [1] which focuses on aspect identification during the requirements engineering and architecture derivation activities. The specific aim of the present workshop is twofold: (a) to initiate creation of an Early Aspects application demonstration and comparisons benchmark; and (b) to solicit submission of new research

Formation and structural characterization of Ni nanoparticles embedded in SiO₂

Face-centered cubic Ni nanoparticles were formed in SiO₂ by ion implantation and thermal annealing. Small-angle x-ray scattering in conjunction with transmission electron microscopy was used to determine the nanoparticle size as a function of annealing temperature, whereas the local atomic structure was measured with x-ray absorption spectroscopy. The influence of finite-size effects on the nanoparticle structural properties was readily apparent and included a decrease in coordination number and bond length and an increase in structural disorder for decreasing nanoparticle size. Such results are consistent with the non-negligible surface-to-volume ratio characteristic of nanoparticles. In addition, temperature-dependent x-ray absorption spectroscopy measurements showed the mean vibrational frequency (as obtained from the Einstein temperature) decreased with decreasing nanoparticle size. This reduction was attributed to the greater influence of the loosely bound, under-coordinated surface atoms prevailing over the effects of capillary pressure, the former enhancing the low frequency modes of the vibrational density of statesThis work was financially supported by the Australian Synchrotron and the Australian Research Council with access to equipment provided by the Australian Nanofabrication Facility

A exploração do melão.

A cultura do melão na região do Submédio São Francisco é praticada por todos os segmentos da produção, desde colonos pouco capitalizados até grandes empresários

Group Theory analysis of phonons in two-dimensional Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDCs) have emerged as a new two dimensional materials field since the monolayer and few-layer limits show different properties when compared to each other and to their respective bulk materials. For example, in some cases when the bulk material is exfoliated down to a monolayer, an indirect-to-direct band gap in the visible range is observed. The number of layers $N$ ($N$ even or odd) drives changes in space group symmetry that are reflected in the optical properties. The understanding of the space group symmetry as a function of the number of layers is therefore important for the correct interpretation of the experimental data. Here we present a thorough group theory study of the symmetry aspects relevant to optical and spectroscopic analysis, for the most common polytypes of TMDCs, i.e. $2Ha$, $2Hc$ and $1T$, as a function of the number of layers. Real space symmetries, the group of the wave vectors, the relevance of inversion symmetry, irreducible representations of the vibrational modes, optical selection rules and Raman tensors are discussed.Comment: 32 pages, 4 figure

A fruticultura como vetor de desenvolvimento: o caso dos municipios de Petrolina (PE) e Juazeiro (BA).

Para contrapor o fenomeno das secas, que frequentemente provocam perda da producao agricola na zona semi-arida do Nordeste, gerando grandes problemas sociais, o governo tem implantado diversos perimetros publicos irrigados e promovido outros estimulos governamentais para a iniciativa privada no setor agropecuario. Atraves dessas iniciativas, o governo tem criado importantes Polos de producao agricola no que diz respeito as pequenas, medias e grandes empresas de producao de frutas e hortalicas. A agricultura irrigada e, mais especificamente, a fruticultura irrigada, promoveu um grande dinamismo na economia do Polo na estrutura urbana tornando-se o aglomerado urbano mais prospero do Vale do Sao Francisco. As grandes mudancas dos sistemas produtivos de culturas anuais para fruteiras perenes, de exportacao, desencadeou no Polo de Petrolina (PE)/Juazeiro (BA) demanda de outros investimentos de apoio para a comercializacao de frutas, motivando o Governo Federal a financiar pesquisas, priorizando aquelas relacionadas com culturas de exportacao, promover cursos de especializacao em comercio exterior e melhorar a infra-estrutura logistica da regiao. A fruticultura irrigada e o principal vetor do desenvolvimento do Submedio Sao Francisco, notadamente das suas cidades Polo, Petrolin,a e Juazeiro, que se constituem em verdadeiros "paraisos"de desenvolvimento dentro do Semi-arido brasileiro. Isto porque com o crescimento da fruticultura se desencadeou uma sinergia de crescimento em praticamente todos os setores produtivos, como o industrial, comercio e turismo. O objetivo deste trabalho e analisar a evolucao do Polo e pontos de estrangulamentos para a ampliacao do desenvolvimento da regiao

Dynamical reentrance and geometry imposed quantization effects in Nb-AlOx-Nb Josephson junction arrays

In this paper, we report on different phenomena related to the magnetic properties of artificially prepared highly ordered (periodic) two-dimensional Josephson junction arrays (2D-JJA) of both shunted and unshunted Nb-AlOx-Nb tunnel junctions. By employing mutual-inductance measurements and using a high-sensitive bridge, we have thoroughly investigated (both experimentally and theoretically) the temperature and magnetic field dependence of complex AC susceptibility of 2D-JJA. We also demonstrate the use of the scanning SQUID microscope for imaging the local flux distribution within our unshunted arrays