1003
However , there is a lack of similar work for improving thermal properties such as thermal conductivity .
 concept or principle: thermal properties; material: as; machanical property: conductivity
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: thermal properties, as, conductivity 
Answer:
 concept or principle: thermal properties; material: as; machanical property: conductivity