Interstitial N diffusion under low energy (approximately 700 eV) Ar+ bombardment at 673 K in ion beam nitrided austenitic stainless steel is investigated. Ar+ ion bombardment increases the N mobility in depths far beyond the ion penetration depth, resulting in an increased broadening of the N depth profile as a function of Ar+ flux. This effect cannot be explained by any established mechanism o...

human activities in the fields of agriculture, municipal and industry introduce significant amounts of nutrients and organic materials into the rivers and streams resulting in their contamination. computer models such as qual2kw are used extensively for water quality management of rivers and streams. the qual2kw model is a one dimensional, non-uniform, steady water quality model, which has been...

Ammonia (NH3) nitridation on an Fe surface was studied by combining density functional theory (DFT) and kinetic Monte Carlo (kMC) calculations. A DFT calculation was performed to obtain the energy barriers (Eb) of the relevant elementary processes. The full mechanism of the exact reaction path was divided into five steps (adsorption, dissociation, surface migration, penetration, and diffusion) ...

Nitrogen-doped graphene oxides (GO:Nx) were synthesized by a partial reduction of graphene oxide (GO) using urea [CO(NH2)2]. Their electronic/bonding structures were investigated using X-ray absorption near-edge structure (XANES), valence-band photoemission spectroscopy (VB-PES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). During GO:Nx synthesis, different ...

Microporous manganese formate shows temperature-triggered gate opening for nitrogen and argon adsorption, which is not due to a structural change of the framework but due to dynamic opening of the pore aperture and/or sufficient kinetic energy of the adsorbates to overcome a diffusion barrier above a critical temperature.

Two L-proline based homochiral frameworks synthesised via diffusion and solvothermal methods display distinct L-proline bonding modes, one N,O chelating and one O,O bridging with amine nitrogen not bound to the metal, with binding mode dependent upon the degree of protonation of the amino acid.

1. Introduction In this work, we utilized molecular dynamics simulations to investigate gas diffusion in realistic nanoporous carbon models. We will focused on how the structure of the porous medium affects the gas diffusion. The porous structural features of interests include topological defects, dangling bonds, size and connectivity of the pores. Through a mimetic virtual synthesis routine, p...

We report the observation of stable optical transitions in nitrogen-vacancy (NV) centers created by ion implantation. Using a combination of high temperature annealing and subsequent surface treatment, we reproducibly create NV centers with zero-phonon lines (ZPL) exhibiting spectral diffusion that is close to the lifetime-limited optical line width. The residual spectral diffusion is further r...

The technologically useful properties of a crystalline solid depend upon the concentration of defects it contains. Here we show that defect concentrations as deep as 0.5 microm within a semiconductor can be profoundly influenced by gas adsorption. Self-diffusion rates within silicon show that nitrogen atoms adsorbed at less than 1% of a monolayer lead to defect concentrations that vary controll...

Niobium superconducting radiofrequency cavities enable applications in modern accelerators and quantum computers. However, the surface resistance significantly deteriorates cavities’ performance. Nitrogen doping treatment can consistently increase cavity performance by reducing resistance, but improvement mechanism is not fully understood. Herein, we employed transmission electron microscopy sp...