TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Dimension: The diameter of the fiber is 30-90 nm. Preferred Material: The material has an electrical function from conductor, semiconductor, insulator, capacitor, electrode or a photoconductor. Preferred Component: The fiber further comprises an outer layer adjacent an outer circumference of the fiber. The fiber has a longitudinal axis. It further has first and/or second region along its longitudinal axis. Preferred Property: The fiber comprises a ductile material that is resistant to chemical corrosion, having a catalytic property and having resistance to 100-1250degreesC. The filter has a thickness of 25-1250 mum. It has pores capable of excluding particles of a minimum size of 1000 daltons to 1 mum and a bulk porosity of at least30%.    TECHNOLOGY FOCUS - METALLURGY - Preferred Material: The metallic fiber is made of stainless steel. The metallic fiber is made of gold, iron, nickel, platinum, silver and/or their alloy. The material is alloy, ceramic, catalyst, intermetallic or glass.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The fiber comprises a combination of a first metal with a second component to form a material. The second component is made from boron, carbon, nitrogen, oxygen, aluminum, silicon, phosphorus, sulfur, nickel, copper, zinc, gallium, germanium, palladium, silver, cadmium, indium, tin, platinum, gold, titanium, rhodium, zirconium, vanadium, titanium tetra-chloride, titanium ethoxide, aluminum sect-butoxide or tetra-carbonyl nickel. The outer layer is made from boron, carbon, nitrogen, oxygen, aluminum, silicon, phosphorus, sulfur, nickel, copper, zinc, gallium, germanium, platinum, silver, indium, titanium tetra-chloride, titanium ethoxide, aluminum sect.-butoxide or tetra-carbonyl nickel. The first metal can be stainless steel, gold, iron, nickel, platinum, silver, titanium, zirconium, niobium or vanadium. Preferred Component: The second component comprises an element from boron, carbon, nitrogen, oxygen, aluminum, silicon, phosphorus, sulfur, nickel, copper, zinc, gallium, germanium, palladium, silver, cadmium, indium, tin, platinum, indium, gold, titanium, rhodium, zirconium or vanadium.