2140
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 ) .
 geometry, thermal expansion coefficient, temperature range, material, thermal expansion, aluminium alloy
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:
 geometry, thermal expansion coefficient, temperature range, material, thermal expansion, aluminium alloy