No abstract

We report fully automated self-calibrating formaldehyde analyzers relying on a hybrid flow format and include operational scheme and design details. Long-term operation is made possible with the use of syringe pumps. Four identical analyzers were built and showed low LODs of 120 pptv or better (S/N = 3) and good linearity over 0-50 ppbv HCHO concentration range (r2 > 0.9960), all concentrations refer to 10 min averaging times. The analyzer can resume normal operation after shortterm power failure with at most two cycles of data loss following restart. Good agreement between analyzers was observed for either indoor or outdoor measurements. The use of an integrated HCHO calibration source and full control by the host computer via a graphical user interface program enables the instrument to switch between zero, calibration, and sampling modes in a programmed automated manner. Detailed field data from deployment in three urban Texas locations from the summer of 2006 are presented. Features of the data, including an episode in which the HCHO concentration exceeded 50 ppbv, the highest reported ambient HCHO concentration in North America to our knowledge, are discussed in some detail.

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The adoption of bi‐layered etch stop layer (BiESL) for oxide thin film transistor with high carrier mobility was proposed for the application to the large area high resolution AMOLED. A novel bi‐layered etch stop structure composed of Al2O3/SiO2, in which thin and dense Al2O3 film prepared by atomic layer deposition was deposited on the PECVD SiO2 layer. High mobility of In‐Ga‐Zn‐O TFT with the proposed BiESL showed no significant change in turn‐on voltage, even without passivation film. The field‐effect saturation mobility and sub‐threshold swing were measured as 29 cm2/V.s and 0.21 V/dec, respectively. Hydrogen doping during the PECVD SiNx passivation process can be effectively prevented by the introduction of Al2O3. Furthermore organic planarization film can be coated directly on top of the TFT array without causing any significant degradation of TFT performance.