Intensity of light emission

The quality of the polymer, its photo-oxidation and thermo-oxidation history expressed in concentration of hydroperoxides, carbonyl groups or of other oxidized structures and terminal groups. The rate of an oxidative attack may then be related to the average molar mass and to its distribution, and to the ratio of amorphous/crystalline structures. Polymers cannot be simply ordered according to the intensity of light emission at a given temperature. The chemiluminescence-time patterns are related with the rate of sample oxidation, but they may differ from one to the next polymer. 

For the mechanism of chemiluminescence in which the intensity of light emission I is proportional to the rate of oxidation w and, therefore, to the concentration of hydroperoxides, the following function of time f may be deduced ... 

Among other factors, the quantum yield of fluorescence determines the intensity of light emission in a CL. This, as well as the position in the spectrum occupied by the fluorescence band, is largely a function of the molecular structure. 

We are discovering exciting parallels between man s experiments on earth and events in distant stars. For example, one of the heavy transuranium isotopes—californium-254, which decays by spontaneous fission with a half-life of 55 days —is now thought to account for the huge energy production in certain types of super-novae (exploding stars) whose intensity of light emission decays with a half-life of 55 days. 

Chemiluminescence is the production of electromagnetic radiation (UV, VIS, or IR) by a chemical reaction between at least two reagents, A and B, in which an electronically excited intermediate or product C is obtained and subsequently relaxes to the ground state with emission of a photon or by donating its energy to another molecule that then luminesces. The intensity of light emission depends on the rate of the chemical reaction, the yield of excited state and the efficiency of light emission from the excited states. 

The absorbance of a substance at a particular wavelength is proportional to the concentration of that substance - a relationship Ccdled the Beer-Lambert law (see p. 392). Similarly, the intensity of light emission by a substance increases with the concentration of emitter. These relationships are useful in finding out the concentration of compounds or elements in mixtures (quantitative analysis). 

Figure 5. Current density and intensity of light emission vs. voltage in Al/MEH-PPV+TBATS/ITOdevice.

Luminescence or fluorescence A wide variety of microorganisms is naturally bioluminescent and/or has been genetically manipulated to incorporate genes encoding for proteins that bring about bioluminescence. In the simplest cases, the intensity of light emission is measured in cuvettes in a conventional luminometer. In other cases, the microorganisms may be attached to fiber optic cables. 

Figure 5. Normalized electroluminescence intensities of light emission (at 580nm) vs. time fox Alll2-doped MEH-PPV/ITO device operated at 12V and 16V in the forward bias mode respectively. Reproduced widi permission from reference 12. Copyright 1997 Society of Photo-Optical Instrumentation Engineers.

The number of photons and the intensity of light emissions (/) are easily measured by CL and BL (Figure 5). The CL-amplitude is proportional to the quantum (dN/dt) or the excited production (dP/dt) rates. 

Provides intensity of light emission Shows peaks of excitation [39]... 

The intensity of light emission in most luminescent marine bacteria and in other bacteria harboring the cloned luxA and luxB genes depends on a number of parameters, including the cAMP system and, in particular, the density of the cell suspension (43). In fact, it is not the cell density per se that directly influences... 

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