A liquid crystal display device of the present invention includes: a liquid crystal display panel; and first and second light diffusing layers, each of which has a first major surface and a second major surface and each of which is arranged such that the first major surface opposes a viewer side surface of the liquid crystal display panel. Such bias voltage circuit may be used with chromatographic ionization detectors as well other devices. Electronic circuitry for processing such response signals has a phase conjugator submitting each received signal to phase conjugation, and the phase-conjugated signals are back transmitted to the passive tags. The substrate can be of gallium arsenide. The or each individual container comprises a cylindrical body of composite material, two end plates closing the axial ends of the cylindrical body, and at least one belt passing around the container substantially in a longitudinal direction and bearing against portions of the outside faces of the end plates. These heating arrangements are connected by electric circuitry to control apparatus so as to permit selection of a cooking temperature in the electric stove.