The authors report the direct observation of a single asperity tungsten tip sliding on graphite by in situ transmission electron microscopy TEM nanomanipulation. The in situ TEM studies have confirmed that graphitic flakes transfer to a sliding tungsten probe, validating proposed friction mechanisms explaining the unique tribological properties of graphite. Wear of graphite was observed, typica...

We calculate and compare the transition paths from graphite to two types of diamond using the variable cell nudged elastic band method. For the phase transition from graphite to cubic diamond, we analyze in detail how the π bonds transit to the σ bonds in an electronic structure. Meanwhile, a new transition path with a lower energy barrier for the transformation from graphite to hexagonal diamo...

Delocalized π electrons in aromatic ring structures generally induce diamagnetism. In graphite oxide, however, π electrons develop ferromagnetism due to the unique structure of the material. The π electrons are only mobile in the graphitic regions of graphite oxide, which are dispersed and surrounded by sp3-hybridized carbon atoms. The spin-glass behavior of graphite oxide is corroborated by th...

Cubic diamond was synthesized with two systems, (1) graphite with pure magnesium carbonate (magnesite) and (2) graphite with mixed potassium and magnesium carbonate at pressures and temperatures above 9.5 GPa, 1600 ±C and 9 GPa, 1650 ±C, respectively. At these conditions (1) the pure magnesite is solid, whereas (2) the mixed carbonate exists as a melt. In this pressure range, graphite seems to ...

The feasibility of edge-functionalization of graphite was tested via the model reaction between pyrene and 4-(2,4,6-trimethylphenyloxy)benzamide (TMPBA) in poly(phosphoric acid) (PPA)/phosphorous pentoxide (P(2)O(5)) medium. The functionalization was confirmed by various characterization techniques. On the basis of the model study, the reaction condition could be extended to the edge-functional...

51) Int. Cl. (57) A mechanochemical oxidation process that allows relatively benign oxidizers to be used for the production of at least partially oxidized graphite, and a method of preparing a carbon fiber using oxidized graphite and a fiber component. Partially oxidized graphite is fully dispersible in water and can be used to prepare thin films with conductivities rivaling pure graphite. This...

Graphite furnace techniques are characterized by excellent analytical sensitivity. They are methods of choice for the determination of trace elements in various environmental, biological, and clinical samples. However, they can be plagued by chemical and background interferences which complicate methods development and sample analysis. Using the graphite platform technique, these interferences ...

A catalytic technique to enhance graphite formation in nongraphitizing carbons was adapted to work with three-dimensional wood-derived scaffolds. Unlike many synthetic graphite precursors, wood and other cellulosic carbons remain largely disordered after high temperature pyrolysis. Using a nickel nitrate liquid catalyst and controlled pyrolysis conditions, wood-derived scaffolds were produced s...

This study demonstrates a facile, mild and environmentally-friendly sustainable (soft processing) approach for the efficient electrochemical exfoliation of graphite using a sodium hydroxide/hydrogen peroxide/water (NaOH/H2O2/H2O) system that can produce high-quality, anodic few-layer graphene nanosheets in 95% yield at ambient reaction conditions. The control experiment conducted using NaOH/H2O...

The MCNP5 Monte Carlo code has been frequently used to model HTGRs with explicit geometric representation of fuel compacts or pebbles, including the microscopic fuel kernels within them. The random locations of fuel kernels within each fuel compact or pebble, and of pebbles within the core, however, present difficulties. A new, on-the-fly, stochastic geometry model for MCNP5 has been developed ...