The value of the boron radii of influence is bigger than the 10% for the atoms that are at less than 5 Å from the B impurities.
The boron radii of influence coincide with the approximate boron effect observed in the PSiHB RDFs and with the contractions of the first and second Si nearest neighbors toward the substitutional impurity calculated by [13, 16] and observed by [17].
(b) Boron radii of influence of the PSiHB models (in blue) compared with the atomic coordinate change produced in a p-type silicon crystal structure due to the presence of a boron impurity (red line).
In Figure 5b, we present the superposition of the PSiHB boron radii of influence (rB) defined in the previous section, and we compare it with the effect of one B atom in a p-type silicon crystal.
However, the most optimized schemes exist only within a small range of boron particle radius, i.e. around 120 μm.
It is calculated that the optimized design of the bundles is set as follows: the absorbent rods number is 19, the cladding thickness is 0.6 mm, the boron carbide pellets radius is 11.84 mm, the air gap thickness is 0.4 mm and the gas plenum length is 1010 mm.
In the 'Results and discussion' section, we report the total radial distribution functions (RDFs), topological radius influence of boron atoms, plane angle distributions, and relative electronic densities (RelD(E s) along planes which contain the first Si neighbors of the B impurities.
The parametric analysis upon two important parameters, i.e. the radius and the volumetric fraction of boron particles, is performed to optimize the OTTO schemes.
We choose atoms of elements Boron (B) and Nitrogen (N) because of their similar atomic radii to that of carbon.
The optical properties of small radius (<1 nm) single wall carbon nanotubes (SWCNTs) alloyed with boron were examined using relaxed C C bond length ab initio calculations in the long wavelength limit.
