Selective annihilation

Dichlorophenoxyacetic acid (2,4-D) is a selective effect herbicide of widely applied for annihilation of bichromatic weeds in sowings of gramineous cultures. 

There is also the normal dipole selection rule in operation, as illustrated in Figure 5.48, due to Liith (1981). Any dipole at a surface induces an image charge within the surface. If the dipole orientation is normal to the surface, the effect is enhanced by the image dipole. If, however, the orientation is parallel to the surface, the effect is annihilated by the image dipole. This orientation selection rule thus strongly favours normally oriented dipoles. 

Fig. 2.5. Possible applications of a coupling parameter, A, in free energy calculations, (a) and (b) correspond, respectively, to simple and coupled modifications of torsional degrees of freedom, involved in the study of conformational equilibria (c) represents an intramolecular, end-to-end reaction coordinate that may be used, for instance, to model the folding of a short peptide (d) symbolizes the alteration of selected nonbonded interactions to estimate relative free energies, in the spirit of site-directed mutagenesis experiments (e) is a simple distance separating chemical species that can be employed in potential of mean force (PMF) calculations and (f) corresponds to the annihilation of selected nonbonded interactions for the estimation of e.g., free energies of solvation. In the examples (a), (b), and (e), the coupling parameter, A, is not independent of the Cartesian coordinates, x. Appropriate metric tensor correction should be considered through a relevant transformation into generalized coordinates...

The mechanism of control with multipulse excitation is likely due to dynamics of the carotenoid donor. The presumably incoherent EET process [1] would not support the observed dependence on the carrier phase via the parameter c. Furthermore, the control effect does not suffer from annihilation at higher excitation intensities [2], as would be characteristic for the delocalised excitons in the B850 ring [1], However, it is well known that femtosecond pulses populate higher ground state vibrational levels by impulsive Raman scattering (IRS) [4], and that the periodic phase modulation (Eq. 1) makes IRS selective for specific vibrations... 

In simulations [9] Sierpinski gaskets on the 12th stage, containing 177147 or 265722 sites, were used respectively. The number No of randomly distributed A or B particles was 10 percent of the total number of sites. The random mutual annihilation of dissimilar particles was simulated through a minimal process method [10] from all AB pairs at each reaction step one pair was selected randomly, according to its reaction rate (3.1.2) the time... 

Bom in early nineteenth century Homeopathy has its own concept about the etiology of a disease. It believes that a spiritual power or vital force animates the healthy organism and keeps it in a harmonious order. During illness the vital force is overwhelmed by a disease force. An artificial disease force, applied through the use of the right remedy, annihilates the original affection and restores health. Sometimes patients do not respond to well selected remedies due to their inherent conditions called miasms. The concept of miasms introduced by Hahnemann has been discussed in Chapter IV. 

This selection rule does not appear to exclude radiationless annihilation and annihilation into a single gamma-ray, but these modes of annihilation are nevertheless forbidden for free positronium. 

Coincidences due to positron annihilation at the foil were recorded for various values of e/p and at several pressures of molecular hydrogen in the range 10-200 torr. From these the data at 100 torr were selected for... 

The third input selected was molecular oxygen its paramagnetism allows it to be a powerful quencher of room temperature phosphorescence in fluid solution. 451 AND logic behavior was arranged in a phosphorescent system, by using p-cydodextrin as one input and Ca2+ as the second input. Room temperature phosphorescent systems such as 29 suffer triplet-triplet annihilations, hence quenching their phosphorescence unless the phosphors are sterically prevented from encountering one another. 

A discussion of the coincidence technique with some general applications has been published by Wahlgren, Wing and Hines 71>. Many of the early applications of the technique made use of the fact that 64Cu is one of the few radionuclides produced by thermal neutron irradiation for which the 0.511 MeV positron annihilation photopeak is a prominent feature of the spectrum. Copper has been determined in meteorites 72> and copper ores 73,74) ]-,y coincidence counting of 04Cu annihilation radiation. The rapid and selective nature of the determination may have important applications in the on-line sorting of copper ores. 

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