Wikipedia
CoNTub is a software project written in Java which runs on Windows, Mac OS X, Linux and Unix Operating systems through any Java-enabled web browser. It is the first implementation of an algorithm for generating 3D structures of arbitrary carbon nanotube connections by means of the placement of non-hexagonal (pentagonal or heptagonal) rings, also referred as defects or disclinations.
The software is a set of tools dedicated to the construction of complex carbon nanotube structures for use in computational chemistry. CoNTub 1.0 was the first implementation for building these complex structures and included nanotube heterojunctions, while CoNTub 2.0 is mainly devoted to three-nanotube junctions. Its aim is to help in the design and research about new nanotube-based devices. CoNTub is based on the strip algebra, and is able to find the unique structure for connecting two specific and arbitrary carbon nanotubes and many of the possible three-tube junctions.
CoNTub generates the geometry of various types of nanotube junctions, i.e., nanotube heterojunctions and three-nanotube junctions, including also single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs).
Although the current version of CoNTub is v2.0, this version does not supersedes v1.0, as v2.0 is dedicated currently to only three-nanotube junctions, although the incorporation of v1.0 functionality into v.2.0 is planned. Nanotube heterojunctions can be generated only with v1.0.
CoNTub v1.0 is organized in five Tabbed panels CoNTub, the first three being dedicated to structure generation, the fourth to the output in PDB format, and the fifth contains a short help section.
CoNTub v2.0 has experimented a major redesign, and the panes have been removed, instead, a conventional menubar has been added where the type of structure to be generated can be chosen. Although the menu item for heterojunction generation appears in the menu, the button is disabled, so NTHJ's can be only generated with v1.0