An ultraviolet light absorber containing, as an active ingredient, a zinc oxide type solid solution %which is represented by the formula, 1xM3xO wherein M3 is a trivalent metal such as Al, Fe, Ce or Ti, x is a number in the range of 0<x<0. A system for treating water is also disclosed and comprises the water heater and a collector disposed in the housing for collecting solid precipitates deposited from the water. The user interface allows the user to describe the desired image, and the tool searches the repository for any images that satisfy the description. The fluid then may be exposed to the light output from the photonic crystals. When an organic coating is formed on an inside surface of the tunneling junction, transient bonds are formed between the electrode layer and the base. Each pixel includes a transistor having one end connected to a data line, and a gate electrode connected to a corresponding gate line, a liquid crystal layer disposed in a tunnel-shaped cavity, first and second electrodes for applying an electric field to the liquid crystal layer.