A Research On The Preparation Of Gas Sensors And Their Application In Preservation Of Fruits And Vegetables

The nano-material SnO₂ was prepared by Sol-Gel method and the side-heating and sintering gas sense was fabricated. Accurately controlling the PH value and proper sintering temperature made the nano-material SnO₂ have single crystal phase with good crystallinity. The structure and character of the solid solution SnO₂ were investigated by X-ray diffraction (XRD) method.The addition element added into SnO₂ is very important to the properties of the SnO₂ based sensor. So the kind and amount of the addition element are the important factorinfecting the sensor properties. In this paper, we add Pd element into SnO₂ materials to improve the sensing materials performance.Moreover, The sensitivity of the final element to 10 ppm ethylene reached 5 when 5% PdCl₂ was doped with the heating current was 120mA, and the selectivity, stability and response-recovery properties were excellent.In our experiments, Alcohol gas sensor based In₂O₃ and sensor for hydrogen sulphide gas based WO₃ also were made with good selectivity, stability and response-recovery properties. The sensitivity of the Alcohol gas sensor to 10 ppm Alcohol reached 6 when the heating current was 100mA and the sensor for hydrogen sulphide gas'to 10 ppm H2S reached 4.5 when the heating current was 100mAThis paper first test the effects of strawberry's storing situation with different humidity , temperature and atmosphere. It is found that hypoxia and CO₂ atmosphere were beneficial for storing and the strawberry lodged healthy for 7 days. Low humidity and C2H4 atmosphere go against the storage and the strawberry decay after 4 days. Then the released gases of strawberry , banana and tomato were tracking tested by the conditions mentioned above. It was found that the released gases was different when the fruits and vegetables from mature to decay. alcohol change greatly before the decay of the fruits and vegetables, the releasing of H2S had a peak in the decaying and ethylene released a lot when the fruits and vegetables decayed thoroughly.