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.

A simulation study on the resolution and sensitivity of magnetic particle imaging

Abstract: This paper presents the first detailed simulation approach to evaluate the proposed imaging method called 'magnetic particle imaging' with respect to resolution and sensitivity. The simulated scanner is large enough to accept human bodies. Together with the choice of field strength and noise the setup is representative for clinical applications. Good resolution, fast image acquisition and high sensitivity are demonstrated for various tracer concentrations, acquisition times, tracer properties and fields of view. Scaling laws for the simple prediction of image quality under the variation of these parameters are derived.

Digitally controlled luminaire system

Abstract: The present invention provides a luminaire system capable of generating light of a desired chromaticity and luminous flux output during continuous operation with varying ambient operating temperature. The luminaire system can be further capable of maintaining a desired correlated colour temperature during dimming of the luminaire. The luminaire system comprises one or more arrays of light-emitting elements for generating light with a current driver system coupled thereto for selectively supplying electrical drive current to each of the arrays, wherein the current driver system is responsive to drive signals received from a controller. The luminaire system further comprises an optical sensor system for generating optical signals representative of chromaticity and luminous flux output of the light. A heat sensing system is operatively coupled to the one or more arrays for generating signals representative of the junction temperatures of arrays of light-emitting elements during operation. The luminaire system further comprises a controller that is operatively connected to the current driver system, the optical sensor system and the heat sensing system for receiving the signals generated by each of these systems and is configured to generate one or more drive signals for transmission to the current driver system in response to the optical signals and thermal signals received from the optical system and the heat sensing system, respectively, thereby enabling a desired level of control of the output light.

Influence of Retardation on the London–van der Waals Forces

Abstract: IN the course of his work on the stability of colloidal solutions, in which the attraction between the particles is ascribed exclusively to London—van der Waals forces, the repulsion being due to the interaction of electric double layers, Overbeek arrived at the conclusion that in order to account for the stability of suspensions of comparatively large particles, it is necessary to assume that for long distances the London—van der Waals energy decreases more rapidly than R-6; and he pointed out that as soon as the distance becomes comparable to the wave-length corresponding to the excitation energies of the interacting atoms, the retardation of the electrostatic interaction between these atoms can no longer be neglected and will presumably lead to a decrease of the attractive force. Following Overbeek's suggestion, we have studied in detail the influence of retardation on the mutual attraction of two neutral atoms. As is well known, the usual expression for the London force is found by calculating the second order perturbation energy due to the interaction: