Second radiation

Since the energy for one photon at this wavelength is 3.6 x 10- J, then the number of photons represented by 1 lumen is approximately 4 X 10i per second, radiated or received. Thus, the luminous flux (lumens, Im) gives the power radiating from an object or the power received by an object. 

Hasegawa and Sato analyzed motion pictures and radiation measurements at a distance of 15 m from the center of the glass vessel. They then correlated, first, fireball duration and maximum diameter to initial fuel mass and, second, radiation to initial vapor pressure. 

Double-resonance spectroscopy involves the use of two different sources of radiation. In the context of EPR, these usually are a microwave and a radiowave or (less common) a microwave and another microwave. The two combinations were originally called ENDOR (electron nuclear double resonance) and ELDOR (electron electron double resonance), but the development of many variations on this theme has led to a wide spectrum of derived techniques and associated acronyms, such as ESEEM (electron spin echo envelope modulation), which is a pulsed variant of ENDOR, or DEER (double electron electron spin resonance), which is a pulsed variant of ELDOR. The basic principle involves the saturation (partially or wholly) of an EPR absorption and the subsequent transfer of spin energy to a different absorption by means of the second radiation, leading to the detection of the difference signal. The requirement of saturability implies operation at close to liquid helium, or even lower, temperatures, which, combined with long experimentation times, produces a... 

G(—COOH), G(CO), and G(Ho) decrease with increase of dose up to 5000 Mrad, but G(COL>) appears to pick up again after an initial decrease (Figure 3). The latter effect might be attributed to second radiation hits on carboxyl end groups, on the grounds that COo is known to be the predominant gaseous product on gamma-irradiation of solid benzoic acid (19). 

Besides the double beam instrument that eliminates background due to light fluctuations from the source by measuring the background radiation from the flame, a second radiation source can be used to determine the absorption of the matrix. 

Emission of cool flame radiation is associated with an early stage in the preflame reactions of most hydrocarbons, as evidenced by the fact that the appearance of cool flames occurs at the same time as the initial pressure development. At a later time in the cycle a second radiation phenomena, described as a blue flame, has been observed under certain conditions (36, 124). A second cool flame also occurring late in the cycle may be the same phenomenon (81, 103, 131). While the importance of cool flame and blue flame phenomena in the over-all reaction mechanism is not fully understood, their occurrences can be used to mark certain stages in the course of the preflame reactions. This principle has been used extensively in studying the effect of hydrocarbon structure, physical variables, and additives on engine preknock reactions. 

This value is inverse of the second radiation constant C2 (hc/k)... 

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