7717
The elastic wave focusing performance of lenses with different design parameters ( gradient coefficient and aperture size ) is simulated numerically under plane wave excitation .
 machanical property: elastic; concept or principle: performance; engineering feature: design; process characterization: excitation
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: elastic, performance, design, excitation 
Answer:
 machanical property: elastic; concept or principle: performance; engineering feature: design; process characterization: excitation