17 research outputs found
A plea for extension of the anatomical nomenclature. Part 1: Nervous system and senses
A correct, exact, concise and detailed anatomical nomenclature is a cornerstone of communication not only in anatomy and related subjects but also in other medical branches and in the whole medical education. Terminologia Anatomica fulfils this task but some important structures are still missing there. The authors have collected and present here a list of terms including their definitions or explanations to provoke discussion about possible extension of the Terminologia Anatomica. The first part of this contribution, presented in this article, comprises 113 terms concerning the regulation systems of the human body: endocrine glands, central and peripheral nervous system, and senses. It also contains some corrections of anatomical mistakes, systemic inconsistencies and grammar changes
Antiferrodistortive phase transition in EuTiO3
X-ray diffraction, dynamical mechanical analysis and infrared reflectivity
studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics.
Near 300K the perovskite structure changes from cubic Pm-3m to tetragonal
I4/mcm due to antiphase tilting of oxygen octahedra along the c axis (a0a0c- in
Glazer notation). The phase transition is analogous to SrTiO3. However, some
ceramics as well as single crystals of EuTiO3 show different infrared
reflectivity spectra bringing evidence of a different crystal structure. In
such samples electron diffraction revealed an incommensurate tetragonal
structure with modulation wavevector q ~ 0.38 a*. Extra phonons in samples with
modulated structure are activated in the IR spectra due to folding of the
Brillouin zone. We propose that defects like Eu3+ and oxygen vacancies strongly
influence the temperature of the phase transition to antiferrodistortive phase
as well as the tendency to incommensurate modulation in EuTiO3.Comment: PRB, in pres