FIG 3 (IMAGE) Compuscript Ltd Caption Fig. 3 Schematic diagram of the C2H2 sensor. (a) The sketch of the QEPAS system based on the four-prong QTF. (b) The sketch of the LITES system based on the four-prong QTF. (c) The picture of the four-prong QTF and the standard QTF. Credit OEA Usage Restrictions Credit must be given to the creator. License CC BY Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.