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By exploiting the configuration of an alternate-current thin-film electroluminescent device, we observe the emission of light from a close-packed spin-cast layer of manganese-doped zinc sulfide nanoparticles (NPs), sandwiched between two dielectric layers, induced by the application of an AC voltage. By means of a microwave-assisted polyol synthesis, we are able to obtain high-crystalline surfactant-free NPs, which can be closely packed in the emitting layer, allowing an emission mechanism due to local charge creation and transport, instead of the typical impact-excitation process. This synthesis route allows us to get rid of a bulk semiconductor layer, implying that far less expensive routes for the active layer deposition such as spin coating, inkjet printing, or spray coating can be used. Our work allows us to get a deeper insight into the role played by the NP structure on the charge-transfer mechanism behind light emission and paves the way to a new generation of non-toxic quantum-dot-based displays. [ABSTRACT FROM AUTHOR]

We quantitatively analyze the thermal emission by anisothermal structures. By comparing the heat flux radiated by simple multilayered systems calculated using the classical Kirchhoff's law to the exact flux derived from a fluctuational-electrodynamics theory, we highlight the limits of validity of the radiometric theory to predict the thermal emission with respect to the geometric configuration, the temperature gradient, and the type of materials and also highlight discrepancies as high as 50%. [ABSTRACT FROM AUTHOR]

A salient effect of strong confinement, especially when quasi one-dimensional, is to drastically alter the phase behavior and concomitantly the physico-chemical properties of a substance encountered in the bulk. The ground state phase diagram of dipolar hard spheres of diameter d as a function of the pore opening , with D being the cylinder diameter of the confining pore, is investigated theoretically. Whereas finding the densest configurations with hard spheres would be a purely geometrical problem, the situation becomes much more intricate with long-ranged anisotropic interactions. As a major finding, long pores prohibit chain undulation (helicity) and wall-contact–free (floating) linear chain bundles emerge. These results shed light on recent experimental observations with magnetic colloids in microtubes. Applications in other fields are discussed as well. [ABSTRACT FROM AUTHOR]

A facility in which a 62 MeV proton beam is employed in the radiotherapeutic treatment of several ocular disease has been active since March 2002 at Laboratori Nazionali del Sud. A fast and accurate quality control system of such beam has been designed and tested. The system consists of a scintillating screen mounted perpendicularly to the beam axis at a fixed distance and observed by a highly sensitive charge-coupled device camera. The basic idea is the possibility to obtain real time information about the relative spatial dose distribution delivered to tissue through the measurement of the light emission in the scintillating screen. A comparison with the presently used dosimetric system (a motorized silicon diode) that, in the future, will be replaced by the device introduced in this paper (if its experimental performance will be successful) has been carried out. The good capabilities of the system make it worthy of further investigations into its applicability in proton beams monitoring for radiotherapeutic treatments (i.e., reconstruction of depth dose distribution and beam monitoring during patient irradiation). Index Terms--Charge-coupled device (CCD), monitoring, proton, scintillator, therapy.

Raman spectroscopy was used in the determination of A1-bearing species that were accountable for the electrodeposition of aluminum in dimethylsulfone solutions of various AlCl3 and LiCl amounts. Raman spectra determined the prevalent presence of AlCl4(super -) ion as the major aluminum chloride species in the dimethylsulfone mixtures even in solutions with no LiCl. The Al2Cl7(super -) was never detected and the Al(DMSO2)3(super 3+) was observed in greater than one AlCl3/LiCl molar ratios.