Y-Capture

Y Capture antibody Colored product ol enzyme substrate... 

Geesey, G. G. and Morita, R. Y., Capture of arginine at low concentration by a marine psychrophilic bacterium, Appl. Environ. Microbiol., 38, 1092, 1979. 

Quite clearly, the neutron-deficiency of the p-nuclides forbids their production in neutron capture chains of the s- or r-types. In contrast, and as already proposed very early in the development of the theory of nucleosynthesis [29], they could well be synthesized from the destruction of pre-existing s- or r-nuclides by different combinations of (p,y) captures, (7,n), (y,p) or (7, a) reactions. Some /J-decays, electron captures or (11,7) reactions can possibly complete the nuclear flow. These reactions may lead directly to the production of a p-nuclide. In most cases, however, they are synthesized through an unstable progenitor that transforms into the stable p-isobar through... 

Anions derived from the aldimine of tiglaldehyde (14) react with carbonyl compounds preferentially at the a-position under conditions of kinetic control to give adducts (15), but products (16) derived from y-attack are obtained under equilibrating conditions (Scheme 4).14 Addition of HMPA to the reaction or adduct mixture is required to promote isomerization of the initially formed a-adduct to the y-product. There is also an increasing preference for y-capture of the unsaturated imine anion as the degree of substitution a to the carbonyl function increases as in a-branched aldehydes and ketones (Table 2). Efforts to isomerize the initial a-adduct formed from reaction of the aldimine derived from crotonaldehyde with cyclohexanecarbaldehyde gave complicated mixtures. 

Radionuclides of high specific activity are produced either through accelerator irradiation or through secondary reactions in the target ( 15.6) in a reactor. Maximum specific activity is obtained when the radioactive nuclide is the only isotope of the element. This is not possible to achieve in regular reactor irradiation through (n,y) capture processes. For example, reactor-produced Na may be obtained in specific activities of 2 X 10 Bq g while the specific activity of accelerator-produced Na may exceed 10 Bq g however, the total activities available are usually the inverse. 

There are a number of ways to reduce corrosion. One is to increase the pH of the water to 8 by adding alkali, e.g. LiOH or NH3 ( 10 ppm). While reactors of US type use LiOH in order to reduce the formation of tritium firom n,y-capture in Li, the VVER reactors normally use KOH. When ammonia is used, the radiolysis yields HNO2 and HNO3 it is necessary to add H2 gas to shift the equilibrium from the acidic products. At an H2 concentration of 2 ppm, the concentration of dissolved O2 is greatly reduced. Instead of NH3, hydrazine or N2 may be added to the water to increase the pH via the reactions... 

The absolute emission probabilities for specified transitions observed in [n y) capture reactions have been obtained by Kinsey [37 ] in certain favourable cases in which the resonance responsible for thermal neutron capture can be identified. The multipolarity is known from level characteristics in many cases. The data can then be compared with theoretical estimates of radiation widths (see Sect. 19). 

Radioactive and (n,y) sources with accurately known energies should be used for the determination of the nonlinearity, e.g., Eu, and ° Ag. The Cl(n,Y) capture lines extend the energy range up to 8.9 MeV (Krusche et al. 1982). Above this energy, there are no better data than those of N(n,y) (Jurney et al. 1997) however, the identification of prompt gamma peaks are not problematic in this energy range. A method has been developed by Fazekas et al. (1999) to fit an overall nonlinearity function with polynomials to separately measured data sets. 

The zirconium process tubes are sufficiently thick in the N Reactor to stop an appreciable fractionof gamma radiation from sources both inside the tube and outside the tube (n y capture in the graphite). Snergy losses due to neutron Interactions in the process tubes are negligible. 

Scintillators which have hydrogen as a constituent, such as organic liquids for example, may be used for fast neutron detection, since the protons produced by fast neutron collisions create the ionization required to operate the detector. In order to adapt a sodium iodide scintillator for the detection of slow neutrons, a small concentration of boron may be distributed in the crystal, giving a particles on neutron capture as discussed above. Alternatively, it is possible to add a neutron absorber which emits 7 rays following the (n, y) capture reaction. Another possibility is the use of lithium iodide (Lil) which, in addition to its own suitability as a scintillator, interacts with neutrons through the reaction... 

The objective function minimizes the total cost (fixed + variable) of setting up and operating the network. The constraint in Equation 5.1 requires that the demand at each regional market be satisfied. The constraint in Equation 5.2 states that no plant can supply more than its capacity. (Clearly, the capacity is 0 if the plant is closed and K( if it is open. The product of terms, A, y captures this effect.) The constraint in Equation 5.3 enforces that each plant is either open (y, = 1)... 

Azapentadienyl anion (31), readily prepared by deprotonation of the /V-allylimine, reacts with carbonyl compounds at either the a- or the 7-position (equation 10). The regioselectivity depends upon the reaction conditions. 1-Azapentadienyl anion (32 equation 11), prepared from the cyclohexylimine of ti-glaldehyde and LDA, reacts with aldehydes and ketones to give the y-capture products in the presence of HMPA or the a-capture products in the absence of HMPA. ... 

Radioactive decay in core Fission, n-y capture, and inelastic scattering in core n 7 capture in core vessel n capture in blanket... 

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