6701
Processing with powder resulted in lower laser energy absorption within the substrate than without powder , due to the “ shadowing ” effect of the powder stream within the beam and loss of energy representing unfused powder .
 powder, laser energy, absorption, substrate, powder, powder, beam, powder
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:
 powder, laser energy, absorption, substrate, powder, powder, beam, powder