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We exploit the inherent resonant frequency dependence on cavity geometry , using a number of TM cavity modes , to determine the thermal expansion coefficient over the temperature range 6–450 K. Our results compare well with literature values and show that the material under test exhibits lower thermal expansion when compared with a bulk aluminium alloy alternative ( 6063 ) .
 concept or principle: geometry; machanical property: thermal expansion coefficient; process parameter: temperature range; material: material; concept or principle: thermal expansion; material: aluminium alloy
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: geometry, thermal expansion coefficient, temperature range, material, thermal expansion, aluminium alloy 
Answer:
 concept or principle: geometry; machanical property: thermal expansion coefficient; process parameter: temperature range; material: material; concept or principle: thermal expansion; material: aluminium alloy