Radiation yield

Wang W, Becker D, Sevilla MD (1993) The influence of hydration on the absolute yields of primary ionic free radicals in y-irradiated DNA at 77 K. Radiat Res 136 146-154 Wang W, Yan M, Becker D, Sevilla MD (1994) The influence of hydration on the absolute yields of primary free radicals in gamma-irradiated DNA at 77 K. II. Individual radical yields. Radiat Res 137 2-10... 

The isotopes of a particular element have the same number of protons in the nucleus but a different number of neutrons, giving them the same proton number (atomic number) but a different nucleon number (mass number, i.e. number of protons + number of neutrons). Isotopes may be stable or radioactive. Radioactive isotopes (radioisotopes) disintegrate spontaneously at random to yield radiation and a decay product. 

The ability of high-temperature ionic solvents to dissolve various substances (e.g. metals or their oxides) is considered among their most important characteristics. In the case of scintillation, single crystals based on alkali-metal halides, some halides-dopants (Til, CeX3, etc.), are available as admixtures since they create levels in the forbidden zone which are responsible for the scintillation. In contrast, oxygen-containing admixtures are harmful since their existence in the crystals causes a considerable reduction in their light-yield, radiation resistance, etc. 

Doses of 150pCi/g (5.5MBq/g) typically yield radiation doses of 12000cGy to the thyroid (Graham and Burman, 1986). Following treatment, radiation exposures to the stomach, marrow, liver and gonads are about 14, 6.8, 4.8 and 2.5 cGy per organ, respectively. The total... 

The reaction mixture is contained in a droplet which is placed on a parafilm-lined glass petri dish the dish in turn is floated on an ice bath. The mixture is then irradiated for varying periods with two 15-watt mercury lamps (General Electric) at a distance of about 7 cm. The lamp yields radiation predominantly at 253 7 nm. Short wavelengths (<210 nm) can be cut off with a 2 mm-thick Vycor glass filter however, in our... 

Huang, S. S. S., Gee, N., and Freeman, G. R., Ionization of liquid argon by X-rays effect of density on electron thermalization and free ion yields, Radiat, Phys, Chem, 37, 417, 1991. 

The effect is related to chain flexibility. Accordingly, miscible blends of rigid with flexible backbone polymers improve the radiation resistance, namely, blending two fluoro-co-polymers or PMMA with PEG or with PVDF yields radiation-resistant blends. 

Mosshauer effect The resonance fluorescence by y-radiation of an atomic nucleus, returning from an excited state to the ground state. The resonance energy is characteristic of the chemical environment of the nucleus and Mossbauer spectroscopy may be used to yield information about this chemical environment. Used particularly in the study of Fe. Sn and Sb compounds. 

This is known as the Planck radiation law. Figure A2.2.3 shows this spectral density fiinction. The surface temperature of a hot body such as a star can be estimated by approximating it by a black body and measuring the frequency at which the maximum emission of radiant energy occurs. It can be shown that the maximum of the Planck spectral density occurs at 2.82. So a measurement of yields an estimate of the... 

The intensity of fluorescence. If, is proportional to the amount of the radiation from the excitation source that is absorbed and the quantum yield for fluorescence... 

Lasers are used to deliver a focused, high density of monochromatic radiation to a sample target, which is vaporized and ionized. The ions are detected in the usual way by any suitable mass spectrometer to produce a mass spectrum. The yield of ions is often increased by using a secondary ion source or a matrix. 

Ra.dia.tlon. Use of radiation to affect fixation of some flame retardants is being investigated (110). Electron-beam fixation requires the selection of compounds that can be insolubilized inside or outside of the fiber with high yield in a short time. Polyunsaturated compounds, eg, Fyrol 76, have shown promise (see Radiation curing). 

Octafluoronaphthalene [313-72-4] is prepared in 53% yield by defluorination of perfluorodecahydronaphthalene [306-94-5] over iron or nickel at 500°C. Exchange fluorination of octachloronaphthalene with KE in sulfolane (235°C) gave 60% yield of octafluoronaphthalene. This product exhibits good StabiHty to ionizing radiation (274). 

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