Spectral radiant intensity

Spectral radiant intensity (lx) The radiant intensity, I, at wavelength X per unit wavelength interval. The SI unit is W m sr , hut a commonly used unit is W... 

The spectral overlap integral J can be expressed in terms of either wavenumbers or wavelengths (Equation 2.36). The area covered by the emission spectrum of D is normalized by definition and the quantities / and lx are the normalized spectral radiant intensities of the donor D expressed in wavenumbers and wavelengths, respectively. Note that the spectral overlap integrals J defined here differ from those relevant for radiative energy transfer (Equation 2.33). Only the spectral distributions of the emission by D /,P and, are normalized, whereas the transition moment for excitation of A enters explicitly by way of the molar absorption coefficient sA. The integrals J" and Jx are equal, because the emission spectrum of D is normalized to unit area and the absorption coefficients sA are equal on both scales. 

How does energy transfer affect the decay kinetics and overall intensity of donor fluorescence In rigid media or highly viscous solvents, where the position of the molecules may be considered as stationary during the lifetime of1D (apart from, possibly, Brownian rotation), the spectral radiant intensity / D due to the fluorescence of 1D decays non-exponentially with time t after excitation of D by a short light pulse, as predicted by Forster67,68 (Equation 2.42) 63... 

When the spectral radiant intensity I within the solid angle of one steradian is incident on the entrance slit of area A, a spectrometer with an acceptance angle n transmits the radiant flux within the spectral interval dA,... 

Nonblack or nongrey bodies are characterized by wavelength dependence of their spectral emissivity. Let be defined as the temperature of the body corresponding to the temperature of a black body. If the ratio of its radiant intensities at the wavelengths Xi, and Xo equals... 

The term intensity is commonly used but is imprecise. According to IUPAC recommendations (see Pure 6[ Appl. Chem. 68, 2223-2286 (1996)), this term should be replaced by the spectral radiant power Ph i.e. the radiant power at wavelength X per unit wavelength... 

I. In reference to a spectral feature, the scalar or magnitude of that feature. 2. Chromatic purity. 3. The magnitude of a particular force or energy per unit (e.g., surface, charge, mass, time, volume, etc.). 4. Synonym for photon irradiance. 5. Synonym for fluence rate. 6. Synonym for irradiance illuminance. 7. Synonym for radiant power. 8. Symbohzed by /, synonym for radiant intensity. 9. See Magnetic Field Strength. 10. See Electric Field Strength. 

Figure 8.3 Spectral radiant power (per unit time per unit area) distribution of a blackbody at various temperatures. Note that the maximum intensity, even at 3500 K, is still in the infrared region of the spectrum. The displacement of the maximum of the radiant energy shifts linearly with absolute temperature (dotted lines) in accordance with Wein s displacement law.

The Planck theory of blackbody radiation provides a first approximation to the spectral distribution, or intensity as a function of wavelength, for the sun. The black-body theory is based upon a "perfect" radiator with a uniform composition, and states that the spectral distribution of energy is a strong function of wavelength and is pro portional to the temperature (in units of absolute temperature, or Kelvin), and several fundamental constants. Spectral radiant exitance (radiant flux per unit area) is de fined as ... 

Spectral irradiance values are based on a total radiant intensity (250-460 nm) of 4,600 uW/cm, a typical light flux for the operating reactor as determined by the trifluralin actinometer. The FS 40 lamp has negligable output at 253.7 nm and several minor emission bands above 500 nm in a region trifluralin does not absorb. 

The angular divergence of the output from a 1-W argon laser is assumed to be 4 X 10 rad. Calculate the radiance L and the radiant intensity / of the laser beam and the irradiance I (intensity) at a surface 1 m away from the output mirror, when the laser beam diameter at the mirror is 2 mm. What is the spectral power density p v) if the laser bandwidth is 1 MHz ... 

The radiant intensity profile for equal amounts of standard MTV decoy flare mix with the above composition is depicted in Figure 10.23. The spectral efficiency for the latter is about twice ( 2.03) in the 2-2.6 pm band. This is due to the much higher Mg content in MTTP formulation (66 vs 54wt% Mg). However, despite the high Mg content, the latter formulation shows a very slow rise in intensity, indicating a slower burn rate. Thus this material would require a different grain geometry to meet with operational rise time specifications. 

Binder (vrt%) Softening agent (wt%) PTFE (wt%) Mg (wt%) Modifier (wt%) Normalized burn rate (mm ) Radiant intensity (Wsr- ) Spectral efficiency Og- sr-i)... 

At sonic velocities, the radiant intensity of MTV barely reaches 10% of the near-static conditions. Hence the spectral efficiency of MTV at increased windspeed is significantly lower and has to be taken into account when designing decoys. Table 10.15 gives the spectral efficiencies for MTV at 150 kts in four different bands. 

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