Adaptive mutation parameter toggling genetic algorithm for phase-only array synthesis

A genetic algorithm that speeds convergence for phased array phase-only synthesis by adaptively toggling between nine mutation parameter pairs is illustrated. This adaptive algorithm outperforms any of the corresponding nine static cases where these same mutation parameters are held constant throughout the optimisation process.     

Study of processes of self-catalyzed growth of gaas crystal nanowires by molecular-beam epitaxy on modified Si (111) surfaces

The processes of growth of self-catalyzed GaAs crystal nanowires on Si (111) surfaces modified by three different methods are studied. For the technology of production of the GaAs nanowires, molecular-beam epitaxy is used. It is found that, in the range of substrate temperatures between 610 and 630°C, the surface density of nanowires and their diameter sharply increases, whereas the temperature dependence of the nanowire length exhibits a maximum at 610°C. An increase in the temperature to 640°C suppresses the formation of nanowires. The method that provides a means for the fabrication of purely cubic GaAs nanowires is described. A theoretical justification of the formation of the cubic phase in self-catalyzed GaAs nanowires is presented.     

LG飞利浦已研制出用于手机的TFT-LCD

LG. Philips LCD （LPL） announced at Sept. 13th 2006, it has developed the industry＇s fastest TFT-LCD panel for mobile phones, which will permit next-generation handsets to display TV and video content with less motion blur.     

An overview of state of the art and research in the fields of sensible, latent and thermo-chemical thermal energy storage

Due to the increase in volatile renewable power and heat generation (wind or solar), thermal energy storage (TES) has obtained growing importance and interest. The technology can be distinguished into three main types: sensible, latent and thermochemical storage. Apart from low and medium temperature heat applications, high temperature TES also is an attractive means to store power in the form of heat (before the thermodynamic transformation process). Thermochemical storage allows for long duration seasonal storage of energy.     

Comparative characterization of chip to epoxy interfaces by molecular modeling and contact angle determination

An investigation of interfacial interaction has been performed between three epoxy molding compound materials and a native silicon dioxide layer (SiO₂) usually found at chip surfaces. The epoxy materials were an industry oriented epoxy molding compound Epoxy Phenol Novolac (EPN), its filled variety EPN^F (with silica particles) and a model aromatic epoxy¹ (2 1 2). All systems are described in full in [1] and [2]. The free surfaces of the solid materials were experimentally analyzed by contact angle measurements of three different liquids (water, methylene-iodide (MI) and glycerol). Results are compared to interfacial energies obtained by analysis of the interfaces in bimaterial molecular models, yielding reasonable agreement. A qualitative prediction regarding the influence of water on the interfacial strength between chip and molding compound is attempted.     

Reliability of ultrathin nitrided oxides grown in low pressure N2O ambient

The influence of N₂O oxynitridation and oxidation pressure on reliability of ultrathin gate oxides from 4 down to 2.5 nm thickness was investigated. A set of different oxidation parameters was applied during oxide growth which comprised oxidation pressure and N₂O partial pressure during rapid thermal oxidation. The reliability of the oxides was tested by constant voltage stress. Evaluation of the resulting times to soft breakdown (t_sbd) for different stress voltages allows to predict a supply (gate) voltage V^10y,max providing an oxide lifetime of 10 years. For this extrapolation, t_sbd was assumed to increase exponentially as stress voltage is reduced. The slope of the extrapolation is found to become steeper as oxides become thinner, which implies higher V^10y,max and thus higher reliability for thinner oxides as under an assumption of a uniform slope for all thicknesses. Further, the results of this extrapolation demonstrate that oxidation in N₂O containing ambient can improve oxide reliability for ultrathin gate oxides.     

Influence of anisotropic strain on excitonic transitions in a-plane GaN films

Hexagonal a-plane GaN films with -orientation were grown by metalorganic vapour phase epitaxy on r-plane sapphire substrates. Spectroscopic ellipsometry in the photon energy range from 1.2 up to 5 eV was applied in order to determine the ordinary and extraordinary complex dielectric function of GaN. A distinct optical anisotropy is found over the whole energy range which is emphasized by reflectance anisotropy studies. The polarization dependent shift of the absorption edges is confirmed by photoreflectance measurements and compared to band structure calculations for which the in-plane strain is taken into account.