Mechanical properties of carbon nanotubes Mechanical properties of carbon nanotubes The mechanical properties of carbon nanotubes reveal them as one of the strongest materials in nature. Carbon nanotubes (CNTs) are long hollow cylinders of graphene. Although graphene sheets have 2D symmetry, carbon nanotubes by geometry have different properties in axial and radial directions. It has been shown that CNTs are very strong in the axial direction. Young's modulus on the order of and tensile strength of were obtained. Carbon nanotubes are the strongest and stiffest materials yet discovered in terms of tensile strength and elastic modulus respectively. This strength results from the covalent sp bonds
Vector model of the atom Vector model of the atom In physics, in particular quantum mechanics, the vector model of the atom is a model of the atom in terms of angular momentum. It can be considered as the extension of the Rutherford-Bohr-Sommerfeld atom model to multi-electron atoms. The model is a convenient representation of the angular momenta of the electrons in the atom. Angular momentum is always split into orbital L, spin S and total J: Given that in quantum mechanics, angular momentum is quantized and there is an uncertainty relation for the components of each vector, the representation turns out to be quite