Mesoscopic clusters function

The field of clusters and fullerenes represents areas of modern science where the properties are determined by the reduced coordination. This will modify the functional properties when clusters are used in disperse forms or as units in cluster assembled materials. Examples of applications can be catalysts, sensor materials, units in nanophase/nanocrystalline materials with improved mechanical, electrical, magnetic or optical properties, of cluster based materials for sun protection, solar energy conversion, as an alternative to quantum dots produced with traditional techniques, fabrication of mesoscopic systems etc. The hope is to tune the properties with cluster size, making cluster based materials with characteristics more advanced than those of conventional materials. Production of these types of cluster and exploration of their properties of free as well as deposited clusters are a challenging task of basic and applied science which will be covered in the following sections of this article. 

Scale matters. We have seen that scale may be used to facilitate reconstruction of structures with nano-components, but it has also shown that scale is important when simulation takes place. When calculated correctly, properly, or if you like, usefully, transport effective coefficients can be determined and even compared to experimental data. However, in some cases new approaches may need to be considered. Here, approaches like mesoscopic physics, or a model of multiple scattering with effective media approximation (EMA) for condensed matter, based on the approach of atomic cluster, may play important roles. Recently, a review (Debe, 2012) was discussed on the different approaches that scientists and fuel cell developers in general, are using in order to have better and cheaper catalysts. Many have made a great impact on CL structures. Some approaches included supporting material but others considered unsupported catalysts too. The aspect ratio of particles has been recognized as a relevant factor. Metallic membranes, meshes, and bulk materials have also been considered of which the structural features will impact on the final structure and functionality of fuel cell technology. Local structures and at different levels of scale are still subjects of interest in many scientific works (Soboleva et al, 2010). 

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