Magnetic Study of α′′α^{\prime\prime} and γ′′γ^{\prime\prime}-Phases of Iron Nitride Thin Films

Most of the Fe-nitride phases have been studied in much detail. Nevertheless, there is still a debate about the most efficient, exact and controlled way of obtaining thin films of the desired iron nitride phases. Thin films of iron nitrides were deposited by Molecular Beam Epitaxy in Ultra High Vacuum. By changing the growth parameters we tried to obtain the α"-phase in its purest form. We worked also on iron mononitride, FeN (γ"-FeN) which is known to exist in different phases. The stoichiometry of the samples was determined by means of resonant Rutherford Backscattering Spectroscopy. The samples were studied by room temperature Conversion Electron Mössbauer Spectroscopy. We achieved as much as 24% of pure α"-phase and provide evidence of the existence of γ"-FeN with vacancies and of the transformation of nonmagnetic γ"-phase into magnetic ε-phase after time exposure

Denticles. A literature review

Denticles are pulp degenerations in the form of calcified deposits of mineral salts, usually found in molars and lower incisors, as well as in impacted teeth and deciduous molars. Denticles may come in various sizes, from microscopic particles to larger mass that almost obliterate the pulp chamber and are visible only on X-ray images. Denticles form as a result of chronic inflammatory lesions, but may also be caused by injuries and conservative treatment. They are most frequently found in necrotic foci. Denticles may cause problems for root canal treatment, as their presence might make it difficult to obtain proper access to the pulp chamber bottom and the canal orifices. There is also the increased risk of bending or breaking the endodontic instruments. Sometimes, denticles fill the entire space of the tooth chamber and pushing the pulp to the edges of the chamber. Denticles can cause pain due to the pressure on the nerves and blood vessels supplying the internal tissue of the tooth. The presence of large denticles might eventually lead to necrosis of the pulp. Denticles accompany certain diseases, such as dentin dysplasia, odontodysplasia or Albright hereditary dystrophy

Sputtering and Implantation of VV-6025X Surface with Slow Heavy Ions Monitored with PIXE

In this work the characteristic radiation, emitted during interaction of medium energy (200 keV) ambient heavy ions (Ar) with $Fe_{4}Co_{66}Si_{12}B_{14}Nb_{1}Mo_{2}Cu_{1}$ (VV-6025X) amorphous alloy, was measured in grazing incident-exit angle geometry and in time sequence, in order to determine dynamics of formation of subsurface region, damaged through implantation, sputtering and interface mixing. It was shown that structure and composition of surface is unstable against heavy ions irradiation due to preferential sputtering and implantation of ions, and recoils, and that the dynamics of such modification can be monitored in-situ with particle induced X-ray emission (PIXE) method

Aza-Peterson Olefinations: Rapid Synthesis of (E)-Alkenes

An aza-Peterson olefination methodology to access 1,3-dienes and stilbene derivatives from the corresponding allyl- or benzyl trimethylsilanes is described. Silanes can be deprotonated using Schlosser’s base and added into N-phenyl imines or ketones to directly give the desired products in high yields