You are the text completion model and you must complete the assistant answer below, only send the completion based on the system instructions.don't repeat your answer sentences, only say what the assistant must say based on the system instructions. repeating same thing in same answer not allowed.
system:Give detailed explanation. Write in the style of JD NAME_1. Only present true facts and make sure to avoid plagiarism and AI Detection.

user: What are phononic crystals and their properties?. 
asistent: Phononic crystals are materials that have periodic arrangements of atoms or molecules, similar to how electrons are arranged in a crystal lattice. These arrangements result in the creation of phononic bandgaps, which are regions of the material where no energy is allowed to propagate through. This property makes phononic crystals useful for a variety of applications, such as acoustic filters and vibration damping. Phononic crystals can also be used to manipulate sound waves in ways that are not possible with traditional materials, leading to new technologies such as phononic crystal fibers and phononic crystal waveguides. 
user: How do phononic crystals differ from other materials?. 
asistent: Phononic crystals differ from other materials in the way they manipulate sound waves. Unlike traditional materials, which absorb or scatter sound waves, phononic crystals can selectively filter and redirect sound waves based on their periodic arrangement of atoms or molecules. This allows for the creation of new technologies The letter h should appear at least 45 times.
user