Radiation spectrum

Figure 1-1 The Blackbody Radiation Spectrum. The short curve on the left is a Rayleigh function of frequency.

Analysis of the electromagnetic radiation spectrum emanating from the star Sirius shows that = 260 nm. Estimate the surface temperature of Sirius. 

Quasi-resonant and resonant transition switching power supplies have a much more attractive radiated spectral shape. This is because the transitions are forced to be at a lower frequency by the resonant elements, hence only the low frequency spectral components are exhibited (below 30MHz). The lower rate of change during the transitions are responsible for behavior. The higher frequency spectral components are almost non existent. The near-held radiated spectrum of a quasi-resonant, hyback converter are shown in Figure E-2. The quasi-resonant and soft switching families of converters are much quieter and easier to hlter. 

Figure E-1 The radiated spectrum of a typical off-line PWM flyback converter.

Figure E-2 The radiated spectrum of a ZVS QR off-line flyback converter.

Apart from a few applications, such as UV disinfection and lacquer hardening, the intensity of UV radiation is well below that of visible light in ambient daylight or indoor lighting. A UV sensor must therefore be insensitive to visible light, otherwise the detection signal would easily be drowned out by the visible fraction of the radiation spectrum. Sensors that fulfill this requirement have a selective spectral sensitivity in the UV range. There are two important selectivities, known as visible-blindness and solar-blindness. 

The heated body emits light with a spectral composition that depends on the material s composition. That observation is not the case for an ideal radiator or absorber ideal objects will absorb and thence re-emit radiation of all frequencies equally and fully. A radiator/absorber of this kind is called a black body, and its radiation spectrum is referred to as black-body radiation, which depends on only one parameter, its temperature, so a hotter body absorbs more light and emits more light. 

The excitation spectrum of a fluorescent material, i.e., the incident radiation spectrum required for the induction of fluorescence, is determined by the absorption spectrum of the fluorescent material, which it often closely resembles, and by the efficiency with which the absorbed energy is transformed into fluorescence. Normally, the excitation spectrum is of higher photon energy (shorter wavelength) than that of the corresponding fluorescence emission, and in sensor schemes this has an effect in the choice of preferred fluorescent agent, compatible with appropriate optical detection devices. 

Figure 2.3 Synchrotron radiation spectrum spectra for various beamlines at the Photon Factory...

Figure 10.1 (a) Distribution of emitted radiation from an electron travelling at relativistic speeds in a circular orbit, (b) The universal, vertically integrated, synchrotron radiation spectrum as a function of reduced wavelength. The axes are calibrated for the SRS at Daresbury Laboratory... 

The phosphor has the following characteristics which are suitable to obtain a high-quality image with a low X-ray dose 1) the absorption coefficient for X-rays is high, 2) PSL radiation is efficiently released under such visible-light stimulation as a He Ne laser beam, 3) the PSL-radiation spectrum falls within the range of... 

Walden, V. P., S. G. Warren, and F. J. Murcray, Measurements of the Downward Longwave Radiation Spectrum over the Antarctic Plateau and Comparisons with a Line-by-Line Radiative Transfer Model for Clear Skies, J. Geophys. Res., 103, 3825-3846 (1998). 

In stellar astronomy, spectroscopic studies are indirectly revealing the structure deep down in stars where one could not see otherwise. An internal structure shows up in the emergent radiation spectrum both kinematically and through abundance anomalies. The solution of the solar corona line problem in 1942 may serve as a typical example of astrophysical applications of atomic spectroscopy [256]. 

It is convenient to employ the shift of mean energy instead of the average energy of the radiation spectrum (32.43), excluding from E(K —K ) the term equal to the difference of two large numbers (energies of final and initial configurations), i.e. 

Having explicit formulas for a number of first moments we can approximately restore the envelope line of the radiation spectrum without its detailed calculations. If lines in the spectrum have one symmetric maximum, then its envelope line is approximated by a normal function whose reconstruction requires only the mean energy and variance of the spectrum. Such an approach is useful for the case of complex spectra consisting of many lines, which, due to low resolutions as well as Doppler and collisional broadening or large natural width, form continuous or quasi-continuous bands. Studies of variation of these statistical characteristics along isoelectronic sequences give a wealth of information on intra-atomic interactions. 

Lines, corresponding to different transitions from initial states with vacancy in the shells with the same n, compose a series of spectra, e.g. K-, L-, M-series etc. Main diagram lines correspond to electric dipole ( 1) transitions between shells with different n. The lines of 2-transitions also belong to diagram lines. Selection rules of 1-radiation as well as the one-particle character of the energy levels of atoms with closed shells and one inner vacancy cause, as a rule, a doublet nature of the spectra, similar to optical spectra of alkaline elements. X-ray spectra are even simpler than optical spectra because their series consist of small numbers of lines, smaller than the number of shells in an atom. The main lines of the X-ray radiation spectrum, corresponding to transitions in inner shells, preserve their character also for the case of an atom with open outer shells, because the outer shells hardly influence the properties of inner shells. 

Radiation spectrum lines, which cannot be explained by the model of one vacancy, historically were also called satellite lines. There are cases, particularly in the long-wavelengths region, when the intensities of satellite lines become comparable to those of diagram lines, or even exceed them. Then the division of X-ray radiation into diagram and satellite lines becomes senseless. 

The presence of an outer open shell in an atom, even if this shell does not participate in the transitions under consideration, influences the X-ray radiation spectrum. Interaction of the vacancy with the open shell, particularly in the final state when the vacancy is not in a deep shell, splits the levels of the core. Depending on level widths and relative strength of various intra-atomic interactions, this multiplet splitting leads to broadening of diagram lines, their asymmetry, the occurrence of satellites, or splitting of the spectrum into large numbers of lines. 

By tuning the potential difference, the device can emit a certain radiation spectrum by varying the incident radiation, the device can generate various electrical currents. In this instance, it is important to concentrate on the electron flux N, just as we did on the heat flux Q in photothermal energy... 

Electromagnetic radiation spectrum from the audible frequency up to that of the cosmic rays. 

Infrared spectroscopy (IR) exploits the absorption of infrared radiation in the 400-4000-cm 1 segment of the radiation spectrum. IR is a generally useful method to help elucidate organic chemical structures (Barker et al., 1956), including the identification of ionizable groups. Thus, IR spectroscopy is an indirect means of detecting charge. Polysaccharides are best examined... 

Bob, says Miss Muxdroozol, hold on a minute. I understand how the Sun can produce a radiation spectrum, like you showed us before, but what s this about dark lines How can the Sun absorb its own light ... 

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