Abstract: An elongate colored structure comprising: an electrically conductive wire; a dye layer surrounding a length of the conductive wire; and an electrically conductive, light transmissive layer surrounding the dye layer; wherein the dye layer is capable of changing its color when a voltage is applied between the conductive wire and the light transmissive layer.

Abstract: The invention is directed to developing a technique to estimate the remaining time for generating electrical power, which is applicable to small fuel cells used as a power supply in small electronic devices such as mobile phones or portable computers. In a fuel cell system including a fuel cell, a fuel used directly or indirectly for the fuel cell, and a module with internal electrical or physical properties that change as the fuel is used, the present invention is characterized by a method for estimating the remaining time in which the fuel or hydrogen created from the fuel can be provided to the fuel cell, where providing a plurality of electrodes inside the module, measuring electrical or physical properties of the space between at least two of said electrodes, and estimating the remaining time based on the measurement results.

Abstract: A kit comprising an inductive charger having a first coil and a portable device having an energy store and a second coil coupled to the energy store whereby the energy store can be charged from a varying electrical field applied across the first coil, the charger and the device being configured remotely from the coils for encouraging coupling between the first and second coils when the charger and the device are located against each other.

Abstract: An elongate coloured structure comprising: an electrically conductive wire; a dye layer surrounding a length of the conductive wire; and an electrically conductive, light transmissive layer surrounding the dye layer; wherein the dye layer is capable of changing its colour when a voltage is applied between the conductive wire and the light transmissive layer.