Philips

About: Philips is a company organization based out in Vantaa, Finland. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 68260 authors who have published 99663 publications receiving 1882329 citations. The organization is also known as: Koninklijke Philips Electronics N.V. & Royal Philips Electronics.

Temperature Dependence of Dielectric Constants of Cubic Ionic Compounds

Abstract: The temperature and pressure dependence of the dielectric constant of a number of cubic halides and oxides with a broad range of dielectric constants have been determined. For low-$\ensuremath{\epsilon}$ compounds the dielectric constant increases with increasing temperature, whereas for high-$\ensuremath{\epsilon}$ compounds the dielectric constant decreases with increasing temperature. Hydrostatic pressure lowers the value of the dielectric constant for all compounds measured. For ferroelectrics and antiferroelectrics a relation has been found between the Curie temperature and the Curie constant. Three effects contribute to the temperature dependence of a dielectric constant: the decrease in the number of polarizable particles per unit volume as the temperature increases, which is a direct result of the volume expansion ($A$), the increase of the macroscopic polarizability due to the volume expansion ($B$), and the temperature dependence of the macroscopic polarizability at constant volume ($C$). The experimental data have been used to calculate these different contributions. It is found that the volume-dependent contribution ($A+B$) is always positive and that the direct temperature contribution ($C$) can be either positive or negative. Where optical data were available in literature they were used to calculate the contributions of the optical and infrared parts of the polarizability to the temperature and volume dependence of the polarizability. The results are discussed with the use of a classical ionic model.

On the heat of formation of solid alloys. II

Abstract: In Part I of this paper [1] it has been shown that a relatively simple atomic model does account for the sign of the heat of formation, ΔH, in a wide variety of alloy systems. Here we consider numerical values of ΔH for solid alloys; a quite satisfactory agreement is obtained for the heat of formation of intermetallic compounds of transition metals, including their borides, carbides and nitrides. Transition metal suicides, germanides, carbides, and nitrides, can be treated in the same way as the other compounds if one allows for an additional positive energy contribution required to convert elementary Si, Ge, C or N2 into a metal (8, 6, 24 and 57 kcal per gram-atom of these four elements, respectively). As an example, predictions for heats of formation of binary intermetallic compounds containing a rare-earth element have been tabulated.

Multiclass linear dimension reduction by weighted pairwise Fisher criteria

Abstract: We derive a class of computationally inexpensive linear dimension reduction criteria by introducing a weighted variant of the well-known K-class Fisher criterion associated with linear discriminant analysis (LDA). It can be seen that LDA weights contributions of individual class pairs according to the Euclidean distance of the respective class means. We generalize upon LDA by introducing a different weighting function.

Technology-assisted training of arm-hand skills in stroke: concepts on reacquisition of motor control and therapist guidelines for rehabilitation technology design.

Abstract: Background It is the purpose of this article to identify and review criteria that rehabilitation technology should meet in order to offer arm-hand training to stroke patients, based on recent principles of motor learning.