The shape of this crystal lattice is very unique.

This concept is difficult.

He showed his gratitude on his face.

He has difficulty expressing his emotions in words.

He was looking outside through the lattice window.

This machine has intense oscillations, so please use it with caution.

This machine oscillates at a constant frequency.

The theory of harmonic oscillators is a fundamental concept in physics.

A phonon is a physical concept that represents the vibration of a crystal lattice.

This crystal has a very beautiful shape.