RESUMO
OH* and CH* chemiluminescence in hydrocarbon flames are often applied to characterize flame structure, equivalence ratio, strain rate, heat release rate, etc. In this study, chemiluminescence images of OH*, CH*, and CO2* in the CH4/O2 diffusion flame were obtained using a CCD camera imaging system. The effect of CO2 dilution on the flame structure, strain rate, and other flame characteristics of CH4/O2 diffusion flame was discussed. The results show that CO2 dilution greatly affects flame morphology and chemiluminescence intensity. There are quantitative functions between the chemiluminescence peak intensity of OH* and CH* and the CO2 dilution level. The CO2* average intensity in the flame zone is better suited to characterize the dilution level than the CO2* peak intensity. Moreover, the strain rate of CO2-diluted laminar flame is defined. It is found that there is a linear relationship between the thickness of the OH* reaction zone and the square root of the strain rate.
RESUMO
A photo-responsive compound BINOL-LA (1) having a rigid backbone ending up with two 5-membered cyclic disulfide moieties was designed. BINOL-LA capped Ag nanoparticles (1@Ag NPs) with a network structure were synthesized in a green way by sunlight or UV lamp irradiation. 1@Ag NPs exhibit a selective recognition towards ClO- in aqueous solution with a switch-on fluorescence response and a visual color change, with detection limits of 0.17 µM and 1.54 µM, respectively. The sensing mechanism is based on the ClO--mediated oxidation of AgS bond, resulting in a disaggregation of 1@Ag NPs assembly. With the strategy demonstrated here, ClO- in tap water and lake water can be detected quantitatively in 5 s.
