The sensitivity and selectivity of gas sensors are related with not only sensing material,but also their operating temperatures.Applying this property,temperature modulation technique has been proposed to improve the ...The sensitivity and selectivity of gas sensors are related with not only sensing material,but also their operating temperatures.Applying this property,temperature modulation technique has been proposed to improve the selectivity of gas sensors.With a newly developed alumina based micro gas sensor,the sensitivity to CO and CH_4 at different operating temperatures was investigated.By modulating the temperature of the sensor at pulse and sine wave modes with different frequencies and amplitudes,the dynamic responses of the sensor were measured and processed.Results show that the modulating waveshape plays an important role in the improvement of selectivity,while the influence of frequency is small at the suitable sampling frequency in the range of 25 mHz～200 mHz.展开更多
A new silicon beam resonator design for a novel gas sensor based on simultaneous conductivity and mass change measurement is investigated. High selectivity and sensitivity in gas detection can be obtained by measuring...A new silicon beam resonator design for a novel gas sensor based on simultaneous conductivity and mass change measurement is investigated. High selectivity and sensitivity in gas detection can be obtained by measuring the charge-to-mass ratio of gas molecules. Structures of silicon beam resonators are designed, simulated, and optimized. This gas sensor is fabricated using sacrificial layer microelectronmechanical system technology, and the resonant frequency of the microbeam is measured.展开更多
We have directly investigated the chemical state of the Pd species in a real l-gas sensor device by examining the l-fluorescence X-ray absorption fine structure. The l-gas sensor device was heavily damaged by a heatin...We have directly investigated the chemical state of the Pd species in a real l-gas sensor device by examining the l-fluorescence X-ray absorption fine structure. The l-gas sensor device was heavily damaged by a heating process in which the temperature was ill-controlled, resulting in decrease of methane selectivity. We found that the Pd O in the fresh l-gas sensor was reduced to Pd metal particles as the methane selectivity decreased. Based on the investigation results, we modified the device structure so as to heat up homogeneously. The lifetime of the sensor was then successfully increased by more than 5 years.展开更多
文摘The sensitivity and selectivity of gas sensors are related with not only sensing material,but also their operating temperatures.Applying this property,temperature modulation technique has been proposed to improve the selectivity of gas sensors.With a newly developed alumina based micro gas sensor,the sensitivity to CO and CH_4 at different operating temperatures was investigated.By modulating the temperature of the sensor at pulse and sine wave modes with different frequencies and amplitudes,the dynamic responses of the sensor were measured and processed.Results show that the modulating waveshape plays an important role in the improvement of selectivity,while the influence of frequency is small at the suitable sampling frequency in the range of 25 mHz～200 mHz.
文摘A new silicon beam resonator design for a novel gas sensor based on simultaneous conductivity and mass change measurement is investigated. High selectivity and sensitivity in gas detection can be obtained by measuring the charge-to-mass ratio of gas molecules. Structures of silicon beam resonators are designed, simulated, and optimized. This gas sensor is fabricated using sacrificial layer microelectronmechanical system technology, and the resonant frequency of the microbeam is measured.
基金High Energy Accelerator Organization under Proposal Number 2012G680
文摘We have directly investigated the chemical state of the Pd species in a real l-gas sensor device by examining the l-fluorescence X-ray absorption fine structure. The l-gas sensor device was heavily damaged by a heating process in which the temperature was ill-controlled, resulting in decrease of methane selectivity. We found that the Pd O in the fresh l-gas sensor was reduced to Pd metal particles as the methane selectivity decreased. Based on the investigation results, we modified the device structure so as to heat up homogeneously. The lifetime of the sensor was then successfully increased by more than 5 years.
