The invention is a sensing method and an oxygen sensor for detecting a change of oxygen partial pressure in an ambient atmosphere. The sensor includes a sensing material selected from metal or its oxides which, when at an elevated temperature and exposed to a gas containing E a changing partial...http://www.google.com.tw/patents/US5798269?utm_source=gb-gplus-share專利 US5798269 - Method for detecting change in oxygen partial pressure based on metal/metal oxide phase transformations 
