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Liquid phase epitaxial growth of InAsâ†0â†.â†9â†1Sbâ†0â†.â†0â†9 and fabrication of 4.2#mu#m light emitting diodes for carbon dioxide detectionMao, Youxin January 1995 (has links)
No description available.
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Studies of some metal phthalocyanines for gas sensor applicationsMohammed, K. A. January 1987 (has links)
No description available.
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An investigation into the production process controlling the manufacture and operation of thick-film tin (IV) oxide gas sensitive devicesSizeland, Eliot January 1994 (has links)
No description available.
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The development and characterisation of conducting polymer based sensors for use in an electronic noseBlair, Neil January 1994 (has links)
No description available.
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Modelling and characterisation of conducting polymer chemoresistorsIngleby, Paul January 1999 (has links)
No description available.
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The investigation of colloidal based conducting polymer films for chemical sensor applicationsEvans, Phillip January 1999 (has links)
No description available.
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The study of heats of adsorption of gases of thin organic films using a novel interferometric micro-calorimeterLione, Richard January 1993 (has links)
No description available.
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Studies of tin oxide gas sensors for gas chromatographic detectionAsh, Peter William January 1990 (has links)
Gas sensitive semiconductors have been known for many years and applied in static gas alarm systems for the monitoring of hazardous gases, however, their application has been limited by a lack of selectivity. In this work a semiconducting gas sensor has been configured for use as a gas chromatographic detector thus combining the sensitivity of semiconductor sensors with the selectivity of gas chromatography. The study has been confined to tin oxide devices, more specifically the Taguchi gas sensor (TGS) . The majority of this work has concentrated on the TGS 813 although the use of other TGS is described. The development of suitable instrumentation is described and rigorous optimisation of the operating parameters e.g. heater voltage and column temperature has been performed using the variable step size simplex technique. Attention was concentrated on the response of the TGS 813 to hydrogen which was used as a test gas. A novel figure of merit, response multiplied by retention time and divided by skew factor was designed so that optimum response was obtained whilst maintaining adequate chromatographic separation. Optimum conditions were verified by univariate searches and the response was observed to be most dependant upon heater voltage. A limit of detection of 20 ppb v/v of hydrogen in a 1 ml sample was obtained at optimal conditions. Illustrative analyses of hydrogen were performed in human breath and laboratory air with results found to be in close agreement with literature values. Calibration was found to be linear over at least three orders of magnitude. The response of the TGS 813 to low molecular weight alkanes has also been investigated. It was observed that different heater voltage optima existed for each of the C1-C5 alkanes and that the sensor was relatively more sensitive to the higher molecular weight compounds. As with hydrogen linear response was obtained over at least three orders of magnitude and an illustrative analysis of natural gas showed excellent agreement with known levels. A compromise optimum heater voltage was used to study the response of the TGS 813 to alcohols, aldehydes, ketones and some Cs hydrocarbons. Capillary columns were used in this investigation and it was noted that they had potentially wider application than packed columns due to the use of an inert carrier with an air make-up flow to the detector. This replaced the air carrier gas used previously which might degrade certain stationary phases. Three different types of TGS: the 813; 822 and 831 were used in a study of the response and skew factor for the detection of halogen-containing compounds. Very high skew factors were often observed, although, for some compounds it appeared that symmetrical peaks could be obtained within narrow heater voltage ranges. Skewed response was observed to be dependant upon sensor type, heater voltage and halogen proportion and type. Analysis of the three sensor types was performed and differences in potential surface area and tin oxide additives observed. The presence of additives was observed to adversely affect sensor recovery.
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Characterization of functionalized and unfuctionalized metal oxide nanoparticle interactions with gas mixtures on porous siliconLaminack, William I. 21 September 2015 (has links)
In order to create more sensitive and accurate gas sensors, we have
studied the interactions of gas mixtures on metal oxide nanoparticle
decorated porous silicon interfaces. The nanoparticles control the
magnitude and direction of electron transduction from the interaction of
analyte gases to an extrinsic porous silicon semiconductor. These
interactions can be predicted by the Inverse Hard Soft Acid Base (IHSAB)
principle. Moreover, the metal oxide nanoparticles can be functionalized
with nitrogen and sulfur, modifying the oxide’s band structure. These
modifications are demonstrated to change analyte interactions in line
with the IHSAB concept and allow for light enhanced sensors. Further we
looked at how the analyte gases interact with other analyte gases on the
surface of these sensors. Studying these systems does two things, first
the research will lead to cheaper, more accurate gas sensors, and second
it helps explore the role of nanoparticles in modifying the interactions
between bulk materials (porous silicon) and molecules (analyte gases).
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Microelectrodes in analysisHodgson, Alexia Wilgith Elsa January 1998 (has links)
No description available.
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