... Diameter: <6 nm 2. Purity: CNTs>90% 3. Length: <15um Double-walled carbon nanotube Carbon nano-tube is the nano grade ... special construction, it has many special properties and can be used in electronics, machinery, medicine, energy, chemicals, optics and other fields ... cathode electron tube technique. Besides, carbon nanotube also can be used in making molecule bearings and nano robot. It is suitable ...