8644
Nanostructure of the films was studied using Doppler broadening of annihilation radiation ( DBAR ) , positron annihilation lifetime ( PAL ) , X - ray photoelectron spectroscopy ( XPS ) , an atomic force microscope ( AFM ) and contact angle measurements .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None