Manipulation of optically fabricated particle arrays using broadband radiation

Consideration is given to methods of manipulating optically fabricated particle arrays using broadband radiation and a superposition of optical fields. Specifically, the changes that the optical binding energy experiences, when part of the spectrum of this light is filtered, are analyzed. It is then shown that these optically induced arrays can be reordered by the introduction of additional fields with transverse Poynting vectors. Subsequently, it is shown how pairs of particles can be reordered on a surface by modifying the form of the optical binding interaction. Finally, the effect of particle size on these methods is briefly discussed

Alternative resonance energy transfer mechanisms in polymer light harvesting

Dendrimeric polymers are a subject of considerable interest, particularly for their applications in energy harvesting devices, but also in organic light-emitting diodes, photosensitizers, quantum logic devices and low-threshold lasers. The distinctive light harvesting characteristics of these materials owe their origin to the speed, efficiency and highly directed nature of the multi-step processes that deliver captured light energy to the core. Recently it has been shown how iterative calculations, based on a matrix representation of the connectivity and propensity for energy transfer between different chromophores, effectively model the time-dependent flux of energy within dendrimer materials. This paper reports the formulation and results of an extended approach, accommodating additional mechanisms by means of which excitations of energy higher than the incoming photons can be generated and propagated towards a trap. It is also shown how the structure of the dendrimer and the operation of a spectroscopic gradient affect this energy flow. These mechanisms explain experimental observations in which energy coupling of four photons or more is observed in large aryl ether azodendrimers, at relatively low levels of irradiance

London force and energy transportation between interfacial surfaces

With appropriately selected optical frequencies, pulses of radiation propagating through a system of chemically distinct and organized components can produce areas of spatially selective excitation. This paper focuses on a system in which there are two absorptive components, each one represented by surface adsorbates arrayed on a pair of juxtaposed interfaces. The adsorbates are chosen to be chemically distinct from the material of the underlying surface. On promotion of any adsorbate molecule to an electronic excited state, its local electronic environment is duly modified, and its London interaction with nearest neighbor molecules becomes accommodated to the new potential energy landscape. If the absorbed energy then transfers to a neighboring adsorbate of another species, so that the latter acquires the excitation, the local electronic environment changes and compensating motion can be expected to occur. Physically, this is achieved through a mechanism of photon absorption and emission by molecular pairs, and by the engagement of resonance transfer of energy between them. This paper presents a detailed analysis of the possibility of optically effecting such modifications to the London force between neutral adsorbates, based on quantum electrodynamics (QED). Thus, a precise link is established between the transfer of excitation and ensuing mechanical effects

Dos mil congressos en un: l'odisea de la diversitat i la igualtat

Abstract not availabl

Sustainable Construction Model for Rehabilitation and Protection of environmentally fragile and degraded areas: Laciana Valley

Coal mining activity was the main source of income in the Laciana Valley region (León,Spain) from the 1950s to the 1980s. This mining activity has left fingerprints in the Laciana landscape, along with completely abandoned buildings and infrastructures. Within the framework of the R&D Spanish National Plan Program (2004-2007) and the Sustainable Construction principles, a research project has been addressed, aiming protection, management, and landscape and built environment planning for this area, as main targets. At the same time, the establishment of guidelines for suitable and sustainable management of future constructions, by promoting activities adapted to the economic development and the social revitalization of the territory, is another aim. By applying sustainable principles for regional planning to new activities, the region?s identity and culture will be reinforced. In other words, a model of sustainable construction for an environmentally deteriorated and fragile area is to be pursued in Laciana Valley