What is a "carbon nanotube" material

In 1991, Japanese experts prepared a material called "nano-carbon tube", which is a tube made up of many hexagonal ring-shaped carbon atoms, or it can be made up of several coaxial tubes. Both ends of such single-layer and multi-layer tubes are often sealed, as shown in FIG. 1.
The diameter and length of the tube composed of carbon atoms are on the order of nanometers, so they are called carbon nanotubes. Its tensile strength is 100 times higher than that of steel, and its conductivity is higher than that of copper.
The carbon nanotubes are heated to about 700°C in the air, so that the carbon atoms at the top of the tube are destroyed by oxidation and become open carbon nanotubes. Then, the low melting point metal (such as lead) is evaporated by electron beam and condensed on the open carbon nanotube. Due to the siphon effect, the metal enters the hollow core of the carbon nanotube. Due to the extremely small diameter of carbon nanotubes, the metal wires formed in the tubes are also particularly thin, known as nanowires, and the size effect it produces is superconductivity. Therefore, carbon nanotubes plus nanowires may become a new type of superconductor.
Nanotechnology is still in its infancy in countries around the world. Although a few countries such as the United States, Japan, and Germany have begun to have a foundation, they are still under study, and the emergence of new theories and technologies is still in the ascendant. China has made efforts to catch up with the level of advanced countries, and the research team is also growing.