Dense machinable α-SiAlON/BN composites were fabricated by hot-pressing using turbostratic boron nitride (tBN) obtained from nitridation of melamine diborate. The tBN was added to the starting powders, or introduced as a coating that formed in situ on α-Si3N4 carrier powders during nitridation, and was subsequently converted to hexagonal boron nitride (hBN) during hot pressing by solution repre...

Field emission cathodes are presently being developed as low-power space electric propulsion neutralizers and for spacecraft charge control and electrodynamic tether applications requiring no consumables. These cathodes effect cold electron emission by the application of a relatively high electric field across a small gap from some kind of electron emitting (cathode) surface. Various designs of...

We explore the generalization to the helical case of the classical Ewald method, the harbinger of all modern self-consistent treatments of waves in crystals, including ab initio electronic structure methods. Ewald-like formulas that do not rely on a unit cell with translational symmetry prove to be numerically tractable and able to provide the crucial component needed for coupling objective mol...

Electroporation in cancer therapy in which elongated micron-sized conductors are used to enhance an externally applied electric field is investigated. Such field enhancement was previously used in carbon and boron nitride nanotube electropermeabilization. It is envisaged that the micro-conductors would be injected together with therapeutic drugs into tumorous regions, and a pulsed or alternatin...

CVD graphene devices on stacked CVD hexagonal boron nitride (hBN) are demonstrated using a novel low-contamination transfer method, and their electrical performance is systematically compared to devices on SiO(2). An order of magnitude improvement in mobility, sheet resistivity, current density, and sustained power is reported when the oxide substrate is covered with five-layer CVD hBN.

Thermal transport and phonon-phonon coupling in monolayer hexagonal boron nitride (h-BN) under equibiaxial strains are investigated from first principles. Phonon spectra at elevated temperatures have been calculated from perturbation theory using the third-order anharmonic force constants. The stiffening of the out-of-plane transverse acoustic mode (ZA) near the Brillouin zone center and the in...