The tubulization process of amorphous carbon nanopillars was observed in situ by transmis-sion electron microscopy. Amorphous carbon nanopillars were transformed into graphitic tubules by annealing at 650-900 degrees C in the presence of iron nanoparticles. A molten catalyst nanoparticle penetrated an amorphous carbon nanopillar, dissolving it, and leaving a graphite track behind. An iron nanop...

Introduction: Nanodiamonds are present in several primitives chondrites [1], from petrologic type 1 to 3.8, together with presolar SiC. They originate from several sources and mechanisms, as shocks in supernovae or condensation in different environments. It is generally believed that they are homogeneously distributed in the nebular gas. Nevertheless, in ordinary chondrites, [2] found a correla...

a r t i c l e i n f o The amorphization and graphitization of single-crystal diamond by ion implantation were explored using transmission electron microscopy (TEM). The effect of ion implantation and annealing on the microstructure was studied in (100) diamond substrates Si + implanted at 1 MeV. At a dose of 1 × 10 15 cm − 2, implants done at 77 K showed a damage layer that evolves into amorpho...

Porous graphitic carbon is an exciting candidate for energy storage applications; by understanding the decomposition of metal precursors used to promote graphitization porosity and bonding structure can be controlled optimised.

it to 680•Ž in flowing nitrogen (PV-7). Four samples having different pre-heat-treatment conditions were selected; the original coke PV-7 , the second one prepared from PV-7 by the heat treatment at 1500•Ž for 60 min (PV-15) , the third also from PV-7 by the treatment at 2060•Ž for 60 min (PV-7-20) , and the fourth by the heat treatment of PV-15 at 2060•Ž for 60 min (PV-15-20). Each sample was ...

Results based on ab initio density functional calculations indicate that cubic diamond, boron nitride, and many other cubic structures including rocksalt share a general graphitization tendency in ultrathin films terminated by close-packed (111) surfaces. Whereas such compounds often show an energy preference for cubic rather than layered atomic arrangements in the bulk, the surface energy of l...

A nitrogen-vacancy (NV(-)) centre in a nanodiamond, levitated in high vacuum, has recently been proposed as a probe for demonstrating mesoscopic centre-of-mass superpositions and for testing quantum gravity. Here, we study the behaviour of optically levitated nanodiamonds containing NV(-) centres at sub-atmospheric pressures and show that while they burn in air, this can be prevented by replaci...

A comprehensive study on the effects of energetic protons on carbon fiber composites and compounds under consideration for use as low-Z pion production targets in future high power accelerators and lowimpedance collimating elements for intercepting TeV-level protons at the Large Hadron Collider has been undertaken addressing two key areas namely thermal shock absorption and resistance to irradi...