An ion-exchange process was developed for the separation of spectrographically pure praseodymium salts in kilogram amounts from commercially available concentrates. The application of either 0.5% or 0.1% citrate solutions as eluting agents was show to result in excellent separations of praseodymium from samarium, neodymium, and lanthanum when the mixed rare earths were eluted from Amberlite IR-...

This paper reviews our recent experimental work on erbium incorporated into gallium arsenide during MBE growth. The electrical behaviour of the erbium is considered in relation to its interaction with intentionally added dopants (silicon, selenium and berylium) and the effect of the erbium on the deep state population is discussed. At higher concentrations the morphology of phase separation is ...

The preparation and the optical properties of lanthanum fluoride (LaF3) nanoparticles doped with erbium and neodymium will be discussed. Organic and inorganic materials in the form of polymers and sol-gels were used to serve as the hosts for the inorganic nanoparticles, respectively. The organic host material has been synthesized such that it is photo-crosslinkable to facilitate straightforward...

Hot super-Earths are exoplanets with masses ≤ 10M⊕ and orbital periods≤ 20 days. Around 8 hot super-Earths have been discovered in the neighborhood of solar system. In this lecture, we review the mechanisms for the formation of hot super-Earths, dynamical effects that play important roles in sculpting the architecture of the multiple planetary systems. Two example systems (HD 40307 and GJ 436) ...