Two-layer model for photopyroelectric spectroscopy

Photopyroelectric detection of organic vapors

The photopyroelectric (PPE) detection of vapors under ambient conditions is demonstrated. A polymer film coated on the transducer is used as sensitive layer. Sorption within this layer binds and concentrates the vapor molecules at the detector surface. Monochromatic IR-radiation selectively excites the sorbed molecules and, therefore, the detected heat is a function of vapor concentration. Prel...

Absolute nonradiative energy-conversion-efficiency spectra in Ti3+:Al2O3 crystals measured by noncontact quadrature photopyroelectric spectroscopy.

Photopyroelectric Spectroscopic Studies of ZnO-MnO2-Co3O4-V2O5 Ceramics

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV f...

Fabrication, characterization, and thermal property evaluation of silver nanofluids

Silver nanoparticles were successfully prepared in two different solvents using a microwave heating technique, with various irradiation times. The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP). The optical properties, thermal properties, and morphology of t...

Adaptive Spectral Separation Two Layer Coding with Error Concealment for Cell Loss Resilience

This paper addresses the issue of cell loss and its consequent effect on video quality in a packet video system, and examines possible compensative measures. In the system's enconder, adaptive spectral separation is used to develop a two-layer coding scheme comprising a high priority layer to carry essential video data and a low priority layer with data to enhance the video image. A two-step er...