Earth field

In conclusion I should like to consider a few of the chemical investigations which might be accomplished in the rare earth field by Mossbauer spectroscopy. The study of nonstoichiometric oxides has been discussed earlier, but there is the problem of finding an appropriate doping nuclide for the praseodymium oxide system. The element most capable of following the changes in oxidation state of the praseodymium is terbium-159, which does have a Mossbauer state, however, with a rather broad resonance (58,0 k.e.v., = 0.13 nsec.). Nevertheless, with a sufiiciently... 

AMBIENT 1 4.0 Oe PLUS EARTH FIELD 4.0 0e MINUS I AMBIENT EARTH FIELD ... 

A reasonably convincing case has been made that the longer-term Holocene trend is a consequence of changes in the Earth s magnetic field which also diverts incoming cosmic rays. This case rests on measurements designed to reconstruct the strength of the Earth field at times in the past. The first such attempt was by... 

Fig. 3-7. Interpretation of the equipotential lines and ionic current flow lines around a singlephase sulphide ore body in a uniform redox field, after the model of Sato and Mooney (1960). Equipotential lines are labelled to depict an upward increasing gradient and are not intended to be an actual representation of the Earth field (from Hamilton, 1998).

Earth field NMR with conventional size coils... 

This volume is a departure from our goal to combine and integrate as far as practical the physics and chemistry of the rare earth elements, in that there is a strong emphasis on the physical aspects, especially of intermetallic compounds. Integration is still our overall goal, but there are times when a particular volume by itself will have a strong emphasis on one aspect of the rare earth field - which is the case here. 

In the comprehensive studies of the radioactive species produced in the fission of uranium it has been found that over thirty are members of the rare earth family (isotopes of yttrium and the group lanthanum through europium). The chemical and physical identification of these was an important part of the research program of the Manhattan Project. Standard oxidative separations and fractional precipitations and the use of radiochemical methods based on chain relations served to distinguish the activities of yttrium, lanthanum, cerium, and some of praseodymium, and those of samarium and europium. The characterization of the sequence praseodymium, neodymium, and element 61 presented very difficult problems that were solved only with the intensification of ion exchange methods originally developed by Boyd and co-workers and applied to the rare earth field by Cohn and co-workers. (Marinsky et al. 1947)... 

The objective in preparing this book is to provide a complete understanding of the background and utilization of ionic liquids in rare earth field - from introductiOTi (Part I) and chemistry of ionic liquids with rare earth (Part II) to ionic liquids for the extraction and separation of rare earth (Part III) and electrodeposition of rare earth metal in ionic liquids (Part IV) and further to the utilization of ionic liquids on rare earth materials (Part V). The order of 9 chapters reflects a logical journey from... 

Lower limit of the evolution field When the evolution field approaches the earth field, i.e. the field when the magnet is switched off, a compensation of this zero-field with the aid of correction coils becomes necessary. In this way, flux densities less than 5 X 10 T can reliably be reached. Another limit is due to the local field within the sample. The local field arises because of secular spin interactions. It can therefore not be compensated by external correction coils. If the local field exceeds the external evolution field, two situations can arise. Firstly, the local field is approached by adiabatically switching off the polarization field. That is, the local magnetization vectors follow the instantaneous field direction which is finally given by the local field. In this case, dipolar or, in the case of quadrupole nuclei, quadru-polar order is produced. The relaxation time measured under such circumstances is the dipolar-order spin-lattice relaxation time. In the opposite case, the... 

Depending on the state of charge of the batteries. Accuracy of the earth field compensation. 

B6n6 GJ (1980) Nuclear magnetism of liquid systems in the Earth field range. Phys Rep 58 213-267... 

---