Electron Density Of Particles Research Articles

The role of thermal noise on key parameters governing the improvement of tokamak fusion reactor efficiency using aneutronic fuel

This article examines the time evolution of energy, particle density, synchrotron radiation loss, plasma frequency, electron particle density, and the relationship between these parameters and blackbody radiation in the presence of thermal noise for the tokamak fusion reactor with aneutronic fuel. To achieve this goal, a suitable thermal noise term is added to the set of energy and particle balance equations. These nonlinear point kinetic coupled differential equations are simultaneously solved by numerical methods. The results of our calculations related to fusion power, particle density, fusion energy density, and quality factor in cases: (i) without and (ii) with noise show that in the conditions where thermal noise is considered, the mentioned parameters and quality factor are increased and in fact system performance improves. Also, our numerical results related to synchrotron radiation loss, plasma frequency, electron particle density, and energy intensity in cases (i) and (ii) show that in the conditions when blackbody radiation occurs (3.75 and 7.225 s respectively for (i) and (ii) cases), synchrotron radiation reaches the maximum values of and for (i) and (ii) cases, respectively.

Molecular-continuum model for the cyanide ion adsorption from aqueous solutions on copper metals

Quantum-chemical calculations of the cyanide ion adsorption from aqueous solutions on copper metals are performed for the first time in a combined molecular–continuum model of polar solvent. The calculations use the cluster model of the surface and are carried out by the density functional in the B3LYP version. The effect of the adsorption system's polar dielectric environment is considered in a self-consistent reactive field model, namely, the SCIPCM model. The dielectric cavity is built in SCIPCM self-consistently with the particle's electron density distribution in solution. Calculations show that the CN– adsorption energy decreases in the sequence Au > Cu > Ag. The calculated energy agrees best with the experimental data when the molecular–continuum model is used, rather than the simpler molecular and continuum models.

Comparison of X-ray structures of the nucleosome core particle in two different hydration states

The X-ray structure of the nucleosome core particle was determined at 7 Å resolution using crystals containing mixed-sequence DNA and 21% to 27% of 1,6-hexanediol (partially dehydrated crystals). The alcohol was added to the crystals after growth to overcome the non-isomorphism of the crystals and improve the quality of their X-ray diffraction. Here, we report the structure of the nucleosome core particle from these crystals in the absence of the alcohol 1,6-hexanediol at 9 Å resolution. The structure, under conditions of nearly full hydration, has been solved by multiple isomorphous replacement methods employing multiple heavy-atom compounds identical to those used for the partially dehydrated structure. The electron density of particles in the two crystal structures is well-correlated throughout the maps and structural elements of the DNA superhelix and histone proteins are generally similar, e.g. the DNA bends sharply at positions ±1 and ±4 double-helical turns from the DNA center. These results rule out the occurrence of gross structural changes in the 7 Å structure due to addition of alcohol. The parts of the nucleosome core particle structure, which are dissimilar between the two forms, can be attributed to differences in molecular packing induced by the addition of 1,6-hexanediol. In contrast to the structure seen in the partially dehydrated crystals, the fully hydrated crystals show a particle in which the H2A-H2B dimers are symmetrically related by the dyad axis found in the H3-H4 tetramer region. However, in the fully hydrated crystals, the first and last double-helical turns of DNA superhelix are not related by dyad symmetry, and one of these segments has reduced contact with the adjacent H2A-H2B dimer.

Inclusion of impurity equations in the 1-D diffusion code of F.A.R

The previous version of the Fontenay-aux-Roses one-dimensional toroidal transport code included four equations for: current density, electron particle density, ion and electron temperatures. In order to represent the impurity behaviour in Tokomak experiments, the authors have considered the presence of four species: carbon, oxygen, iron and molybdenum. As the energy equipartition between ions (light ions, denoted by H, as well as impurities) is much more efficient than equipartition with electrons, it is assumed that all the ions have the same temperature T. This assumption allows one to keep only one heat equation for all the ions.