Sensitivity chemical sensors

In recent years further concepts have been developed for the construction of polymer-based diodes, requiring either two conjugated polymers (PA and poly(A-methyl-pyrrole) 2 > or poly(A-methylpyrrole in a p-type silicon wafer solid-state field-effect transistor By modifying the transistor switching, these electronic devices can also be employed as pH-sensitive chemical sensors or as hydrogen or oxygen sensors 221) in aqueous solutions. Recently a PPy alcohol sensor has also been reported 222). 

In another study, Darrach et al. [2] reported that samples collected near intact UUXO targets contained traces of explosives at up to parts per billion (ppb) concentration levels. The samples were analyzed in the laboratory, using solid-phase microextraction (SPME) to extract target analytes from the samples. The samples were then processed using a reversal electron attachment detection (READ) technique. If the levels of contamination found in these studies are representative of that emanating from most UUXO, the implication is that sensitive chemical sensors such as the SeaDog may be useful for detecting UUXO. 

Cusano A, ladicicco A, Campopiano S, Ciordano M, Cutolo A (2005) Thinned and micro-structured fiber bragg gratings towards new all fiber high sensitivity chemical sensors. J Opt A Pure Appl Opt 7 734-741... 

Shu X, Huang D (1999) Highly sensitive chemical sensor based on the measurement of the separation of dual resonant peaks in a 100-pm period fiber grating. Opt Commun 171 65-69... 

Photoluminescence. Luminescence phenomena introduced previously are the basis of extremely sensitive chemical sensors. They measure the intensity of light emitted when molecules return from excited to ground state. In lumines-... 

Both propagation modes of acoustic waves may be utilized to construct mass-sensitive chemical sensors. Wave propagation through the bulk is the basis of so-called bulk acoustic wave (BAW) devices. Propagation along the surface is used in surface acoustic wave (SAW) sensors. 

Table 4.1. Examples of adsorptive layers which can be used in mass sensitive chemical sensors...

Porous Silicon for Environmental Monitoring. While the exact mechanism of the SO2 interaction is still under investigation, the utility of p-PS as a sensitive chemical sensor of SO2 is illustrated in Figure 6. Low concentrations of SO2 (less than 5%) in At produce a large decrease in PL intensity of about 20-30%. For S02/Ar mixtures between 28 and 194 ppm, a change in PL intensity of 2% was obtained. These changes were near the limit of detection for the fluorimeter employed due to a poor signal to noise response. In 100% SO2 the PL of p-PS is reduced to -70% of the initial... 

Rahman MM, Jamal A, Faisal M (2011) CuO codoped ZnO based nanostructured materials for sensitive chemical sensor applications. App Mater Interf 3 1346-1353... 

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