Biomedical subjects

E Landree

Publications and source records attributed to E Landree.

4 recordsLinked to original sources

PubMed1999

Heterostructures of single-walled carbon nanotubes and carbide nanorods

A method based on a controlled solid-solid reaction was used to fabricate heterostructures between single-walled carbon nanotubes (SWCNTs) and nanorods or particles of silicon carbide and transition metal carbides. Characterization by high-resolution transmission electron microscopy and electron diffraction indicates that the heterostructures have well-defined crystalline interfaces. The SWCNT/carbide interface, with a nanometer-scale area defined by the cross section of a SWCNT bundle or of a single nanotube, represents the smallest heterojunction that can be achieved using carbon nanotubes, and it can be expected to play an important role in the future fabrication of hybrid nanodevices.

Journal Article↗

PubMed1999

Electron crystallography in surface structure analysis.

Surface structure analysis is an important area of research, and in recent years notable advances have been made in this field, both in improved techniques for studying surfaces and in methods of analyzing them. This review aims to summarize the techniques available, particularly those relating to electron microscopy, and also to outline one of the newest areas of development, the application of direct methods to surface structure analysis.

Algorithms↗

PubMed1999

A feasible set approach to the crystallographic phase problem.

The connection between the crystallographic phase problem and the feasible set approach is explored. It is argued that solving the crystallographic phase problem is formally equivalent to a feasible set problem using a statistical operator interpretable via a log-likelihood functional, projection onto the non-convex set of experimental structure factors coupled with a phase-extension constraint and mapping onto atomic positions. In no way does this disagree with or dispute any of the existing statistical relationships available in the literature; instead it expands understanding of how the algorithms work. Making this connection opens the door to the application of a number of well developed mathematical tools in functional analysis. Furthermore, a number of known results in image recovery can be exploited both to optimize existing algorithms and to develop new and improved algorithms.

Journal Article↗

PubMed1998

In situ growth and characterization of ultrahard thin films.

Results concerning the operation of a new ultrahigh vacuum (UHV) ion-beam assisted deposition system for in situ investigation of ultrahard thin films are reported. A molecular beam epitaxy (MBE) chamber attached to a surface science system (SPEAR) has been redesigned for deposition of cubic-boron nitride thin films. In situ thin film processing capability of the overall system is demonstrated in preliminary studies on deposition of boron nitride films on clean Si (001) substrates, combining thin film growth with electron microscopy and surface characterization, all in situ.

Boron Compounds↗