... composite-based gas sensors operated at
room temperature are still lacking.
The NH
3
gas sensors based on CNTs [25,26] and SnO
2
[27–31] have been extensively investigated. The SnO
2
-based gas
sensors ... p-type semiconductor [12–15,25–28]. Comparing
with the CNTs-based NH
3
sensor [27,29] and the SnO
2
-based
NH
3
sensor [29–31] reported previously, as-synthesized com-
posites...
... nanocomposite thin films.
3.4. Gas response and recovery characterization
Fig. 6 shows the gas response of the ZnO-based gas sen-
sors including a pure nano-crystalline ZnO film and the four
Fe
2
O
3
–ZnO ... of the gas sensors based on: (a) 2% and (b) 4% Fe
2
O
3
–ZnO
nanocomposites.
Table 1 summarizes the sensor signal (response magnitude),
response time and recovery time of...
... incorpo-
rated in gas sensors for the detection of ethanol gas [54], benzene,
xylene and toluene [55].
Other studies focused on ammonia gas sensors using polypyr-
role as sensitive layer. Thus, an ammonia ... NH
3
vapors and (b) schematic drawing of the ammonia gas sensor.
2. Experimental
2.1. Fabrication of gas sensors
The gas sensors were fabricated using microsyst...
... temperature
and 300 8C) in order to better relate structural and gas-
sensing properties.
Sensors and Actuators B 93 (2003) 475–485
*
Corresponding author. Tel.: þ3 4-9 3 4-0 2 1-1 46; fax: þ3 4-9 3 4-0 2 1-1 48.
E-mail ... understand the sensor
response to NO
2
and H
2
S of gas sensors based on differently
annealed WO
3
. Thick-film gas sensors based on differently...
... of operating temperature for as-deposited Al-
activated WO
3
films exposed to 10 ppm H
2
S (right-hand scale), 5 ppm NO
2
(left-hand scale), and 100 ppm CO (left-hand scale). The lines are guide ... response of an as-deposited Au-activated WO
3
sensor upon
CO (50 and 100 ppm) and NO
2
(5 and 10 ppm) exposures at 700 K operating
temperature.
132 L.F. Reyes et al. / Sensors and Actua...
... (which detects both DENV-1 and DENV-2)
were 2.0 and 0.9% for DENV-1 and DENV-2, respec-
tively, and 1, 1.8, 4.4 and 3.4% for groups 2 (2G2P5),
3 (1G3P6), 4 (1G4P217) and 5 (1G5P30), respectively,
with ... DENV and human RNA
Primers were further tested with total RNA extracted
from DENV-1 (Piura, Peru )-, DENV-2 (New Guinea C )-,
DENV-3 (Asuncion, Paraguay )- or DENV-4 (D...