7796
When the ultrasonic power is 180 W , the porosity reaches a minimum of 0.1±0.05 % and the relative density is 99.9±0.1 % .
 power, porosity, relative density
Please list all entity words in the text that fit the category. Output format is "word1, 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} 
Answer:
 power, porosity, relative density