Semiconductor nano-particles, due to their specific physical properties, can be used as reversible photo-bleachable materials for a wide spectrum, from far infrared to deep UV. Slots are allocated by assigning a first data rate to each remote station for communication using the first frequency reuse zone. An outer covering, such as a thermally conductive thermoplastic material, encapsulates at least a substantial portion of the armature assembly. A separate source retaining leaf may be provided having holding means for retaining the original source from which the images displayed on the album leaf originated. The method also enables the conference to automatically terminate after all conference participants leave the conference.