Radiation, mercury

The application of classical Raman spectroscopy, using the mercury radiation at A 253.6 nm as the excitation source, permitted recording20 of more than 20 peaks for sucrose below 500 cm-1. The observed frequencies below 100 cm"1 were interpreted as due to inter-ring oscillations, which was also the conclusion reached from a far-infrared study84 of glucose and sucrose. 

Figure 5d. Depth Profile of Polyethylene Surface - Mercury Radiation Induced Photoelectron Neutralization...

The intensity and penetrating power of the mercury radiation projected in the direction of motion of the electrons and also perpendicular to it have been measured by means of the ionizing effects produced inside of the ionization chamber. These experiments have been made in order to determine whether or not the beams of rays are homogeneous, and, also, to compare the penetration with that to be expected according to certain theoretical distributions of energy in the spectrum of radiation due to the impacts of electrons of given velocity. The material used to de-... 

The mercury radiation through the window, if, appeared to be slightly more penetrating than that through the window, G. This, however, is due to the fact that the mica in window, Hy was somewhat thinner than that in window, G, as will be seen later. 

The intensity of the mercury radiation coming through the window, Hy appeared to be five or six times as great as that coming through the window, G. It would be difficult to estimate accurately how much of this difference may be due to the fact that the beams came from different thicknesses of mercury vapor. We may conclude, however, that the intensities per mercmy atom in the direction of motion of the electron and perpendicular to it are of the same order of magnitude. Further experiments on this point are in progress. 

An attempt to obtain a spectrum of the mercury radiation is being made by means of a small spectrometer inside the tube. 

Early Raman spectroscopy instruments saw little forensic use. Illumination sources were mercury vapor lamps with filters that isolated specific mercury radiation wavelengths. Sample sizes were rather large and Raman spectra were captured on photographic film. The detection of weak spectral lines sometimes required days of operation and film exposure. Today s instruments use of laser... 

Sources of radiation are all of lower than ideal intensity. One of the most commonly used is a mercury discharge in a quartz envelope, most of the higher-wavenumber radiation coming from the quartz rather than from the discharge plasma. 

Laser radiation is very much more intense, and the line width much smaller, than that from, for example, a mercury arc, which was commonly used as a Raman source before 1960. As a result, weaker Raman scattering can now be observed and higher resolution is obtainable. 

In practice, o2one concentrations obtained by commercial uv devices ate low. This is because the low intensity, low pressure mercury lamps employed produce not only the 185-nm radiation responsible for o2one formation, but also the 254-nm radiation that destroys o2one, resulting in a quantum yield of - 0.5 compared to the theoretical yield of 2.0. Furthermore, the low efficiency (- 1%) of these lamps results in a low o2one production rate of 2 g/kWh (100). 

Ultraviolet light sources are based on the mercury vapor arc. The mercury is enclosed ia a quart2 tube and a potential is appHed to electrodes at either end of the tube. The electrodes can be of iron, tungsten, or other metals and the pressure ia a mercury vapor lamp may range from less than 0.1 to >1 MPa (<1 to >10 atm). As the mercury pressure and lamp operating temperatures are iacreased, the radiation becomes more iatense and the width of the emission lines iacreases (17). 

The effective absorption of radiation by a gas can be increased by the addition of a sensitizer. For example, when mercuty vapour is added to silane gas, the mercury vapour absorbs radiation to form an excited atom Hg which collides with a silane molecule to lead to partial dissociation... 

One way of implementing the UV disinfection process at existing activated sludge plants involves suspending the UV lights (in the form of low-pressure mercury arc UV lamps with associated reflectors) above the secondary clarifiers. The effluent is exposed to the UV radiation as it rises over the wire in a thin film. 

Mercury line radiators are normally employed these are readily available as... 

A continuous source has to be employed to record absorption spectra. Fluorescence is usually excited with mercury vapor lamps in the region of their major bands they radiate more powerfully than do xenon lamps (Fig. 14). 

However, the optical train illustrated in Figure 22B allows the determination of fluorescence quenching. The interfering effect described above now becomes the major effect and determines the result obtained. For this purpose the deuterium lamp is replaced by a mercury vapor lamp, whose short-wavelength emission line (2 = 254 nm) excites the luminescence indicator in the layer. Since the radiation intensity is now much greater than was the case for the deuterium lamp, the fluorescence emitted by the indicator is also much more intense and is, thus, readily measured. 

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