368 research outputs found
Prediction of triple point fermions in simple half-Heusler topological insulators
We predict the existence of triple point fermions in the band structure of
several half-Heusler topological insulators by calculations and the
Kane model. We find that many half-Heusler compounds exhibit multiple triple
points along four independent axes, through which the doubly degenerate
conduction bands and the nondegenerate valence band cross each other linearly
nearby the Fermi energy. When projected from the bulk to the (111) surface,
most of these triple points are located far away from the surface
point, as distinct from previously reported triple point fermion
candidates. These isolated triple points give rise to Fermi arcs on the
surface, that can be readily detected by photoemission spectroscopy or scanning
tunneling spectroscopy.Comment: 6 pages, 3 figures. The supplementary information is attached in the
latex packag
Exploring the Potential of Electrical Impedance Tomography for Tissue Engineering Applications
In tissue engineering, cells are generally cultured in biomaterials to generate three-dimensional artificial tissues to repair or replace damaged parts and re-establish normal functions of the body. Characterizing cell growth and viability in these bioscaffolds is challenging, and is currently achieved by destructive end-point biological assays. In this study, we explore the potential to use electrical impedance tomography (EIT) as a label-free and non-destructive technology to assess cell growth and viability. The key challenge in the tissue engineering application is to detect the small change of conductivity associated with sparse cell distributions in regards to the size of the hosting scaffold, i.e., low volume fraction, until they assemble into a larger tissue-like structure. We show proof-of-principle data, measure cells within both a hydrogel and a microporous scaffold with an ad-hoc EIT equipment, and introduce the frequency difference technique to improve the reconstruction
- …