High positioning

A positive ion formed on such a tip held at a high positive potential is repelled and flies olf the tip almost immediately after formation and into the mass spectrometer, where its m/z value is measured. Similarly, negative ions can be mass measured. 

Therefore, the sample solution, which may or may not come from a liquid chromatographic column, is passed along a narrow capillary tube, the end of which is maintained at a high positive or negative potential. 

Cytodex 1 Pharmacia, Sweden 147-248 dextran, high positive charge... 

When the hydropathy indices are plotted against residue numbers, the resulting curves, called hydropathy plots, identify possible transmemhrane helices as broad peaks with high positive values. Such hydropathy plots are shown in Figure 12.23 for the L and M chains of the reaction center. 

Proper vessel designs should avoid discharges from high-positioned coolers directed down a pipe. This situation reduces pressure in coolers via siphon action. 

Tnflic acid is an excellent catalyst for the nitration of aromatic compounds [.S7]. In a mixture with nitnc acid, it forms the highly electrophilic nitronium inflate, which can be isolated as a white crystalline solid Nitronium inflate is a powerful nitrating reagent in inert organie solvents and in tnflic acid or sulfuric acid. It nitrates benzene, toluene, chlorobenzene, nitrobenzene, m-xylene, and benzotn-fluoride quantitatively in the temperature range of-110 to 30 °C with exeeptionally high positional selectivity [87],... 

In order to distinguish between kinetic and thermodynamic phenomena it is convenient to refer to the former as the 7tr/ i-effect and the latter as the tra/u-influence or static /ra/u-effect". though this nomenclature is by no means universally accepted. However, it appears that to account satisfactorily for the kinetic /rau.s-effect , both it (kinetic) and a (thermodynamic) effects must be invoked to greater or les.ser extents. Thus, for ligands which are low in the Trans series (e.g. halides), the order can be explained on the basis of a u effect whereas for ligands which arc high in the series the order is best interpreted on the basis of a jt effect. Even so, the relatively high position of H , which can have no rr-acceptor properties, seems to be a result of a a mechanism or some other interaction. 

These data have been obtained by anodic polarisation work and might therefore be more relevant when cathodic reduction of oxygen takes place that can increase the corrosion potential to high positive values. 

As shown by Frank and Evans 41 , solutions of apolar substances in water are characterized by a large entropy of mixing, leading to a high positive free energy of dissolving. 

Low substrate selectivity accompanying high positional selectivity was also found in isopropylation of a range of alkyl and halogenobenzenes by /-propyl bromide or propene in nitromethane, tetramethylene sulphone, sulphur dioxide, or carbon disulphide, as indicated by the relative rates in Table 86. The toluene benzene reactivity ratio was measured under a wide range of conditions, and varied with /-propyl bromide (at 25 °C) from 1.41 (aluminium chloride-sulphur... 

The impure copper from either process is refined electrolytically it is made into anodes and plated onto cathodes of pure copper. Other metals may be present in the impure copper and those with highly positive electrode potentials also are reduced. The rare metals—most notably, platinum, silver, and gold—obtained from the anode sludge are sold to recover much of the cost of the electricity used in the electrolysis. 

Hard Acids. The acceptor atoms are small, have high positive charge, and do not contain unshared pairs in their valence shells. They have low polarizability and high electronegativity. 

When an excited state is converted by ejection of an atomic electron, a high positive charge can be produced through subsequent Auger electron emission. Within the period of molecular vibration this charge is spread throughout the molecule to all atoms, and a Coulomb explosion results. This primary phenomenon occurs, of course, not only as a result of [ decay, but must be taken into account in all cases of nuclear reaction when deexcitation by inner electron conversion occurs... 

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