Photo-thermal effect

We conclude that the cfs-planar isomer is the dominating 84 species in equilibrium sulfur vapor and the trans-planar isomer is generated by photo-thermal effects during laser irradiation [23] or by the microwave discharge applied to the sulfur vapor before matrix isolation [43]. 

Polyimides, chlorinated poly(methylstyrene) and novolac resins are all crosslinking polymers under ordinary UV light irradiation, whereas PMMA and PMGI are main-chain scission-type polymers under deep UV irradiation (23). Even for such scission-type polymers, photo-thermal effects cannot be neglected. For crosslinking-type polymers, photo-thermal effects become more important and are the predominant mechanism for photo-ablation. 

In a passive mode, such devices function like thermocouple probes described above. These can be used (for example) to map the temperature distribution in energised electronic devices simultaneously with their topography [38,39]. If the surface is illuminated with infrared radiation, the photo-thermal effect arising from the absorption of energy specific to the infra-red (IR) active modes of the specimen may be used to obtain the sample s IR spectrum [40-47]. In the active mode, the heat flow from the tip can be used to detect surface and subsurface defects of different thermal conductivity than the matrix [48,49]. 

Upon absorption of an intense laser pulse by a solid sample, temperature is known to rise [112] however, the cooling time should be a microsecond-order event. In the present study, the authors eliminated the possibility of thermal effects contributing to the photo-coloration by simply splitting the laser pulse and delaying the two pulses by up to a few nanoseconds. In this case, the overall two-... 

In general, there is a paucity of information on the relationship between polymer structure and degradation kinetics. This becomes especially critical in multiphase polymers like heterophasic copolymers, thermoplastic elastomers and blends. This review should stimulate research in this important area, which could ultimately lead to polymers with better photo-thermal and radiation resistance as well as more effective stabilizers. 

Photo-Induced and Thermal Effects on Biological Material... 

In another example, a mixed monolayer composed of a photoisomerizabie component and an electrochemical catalyst was applied to switch the electrocatalytic properties of a modified eleetrode between ON and OFF states. A Au-electrode surface functionalized with a nitrospiropyran mono-layer and PQQ moieties incorporated into the monolayer was applied to control the electrocatalytic oxidation of 1,4-dihydri-P-nicotinamide adenine dinucleotide (NADH) by light. The positively charged nitromerocyanine-state interface resulted in the repulsion of Ca cations, which are promoters for the NADH oxidation by the PQQ, thus resulting in the inhibition of the electrocatalytic process. In the nitrospiropyran state, the monolayer does not prevent the association of the PQQ catalyst and promoter thus it provides efficient electrocatalytic oxidation of NADH. Similar outcomes have been achieved using a combination of the photo- and thermal effects resulting... 

High quality IR spectra of different carbon surfaces were obtained by photo-thermal beam deflection spectroscopy (IR-PBDS) [123,124]. This technique was developed with the intention of providing an IR technique that could be used to study the surface properties of materials that are difficult or impossible to examine by conventional means. Recently, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) has been successfully applied to study the effect of different pretreatments on the surface functional groups of carbon materials [101,125-128]. Several studies aiming to improve the characterization of the carbon electrode surface and the electrode-electrolyte interface have been carried out using various in situ IR techniques [14,128-132]. The development of in situ spec-troelectrochemical methods has made it possible to detect changes in the surface oxides in electrolyte solutions during electrochemical actions. 

Recent careful work has shown, once associated thermal effects are eliminated, that photo-effects are absent from H2 adsorption or from H2/D2 exchange rate, at least over the wavelength range 200—800 nm. 

The SiH4/02 and SiH4/N20 routes to Si02 thin films are perhaps the most widely studied photochemical CVD of dielectrics [21], mainly due to their importance in VLSI technology. Photo-CVD of Si02 provides a suitable route to deposition at low substrate temperatures, thereby avoiding potential thermal effects of wafer warpage and deleterious dopant redistribution. In addition, other low temperature methods, such as APCVD and PECVD, often provide poor purity of films. 

---