Effective low energy Hamiltonians and unconventional Landau level spectrum of monolayer C3_3N

We derive a low-energy effective $\mathbf{k}\cdot\mathbf{p}$ Hamiltonians for monolayer C$_{3}$N at the $\Gamma$ and $M$ points of the Brillouin zone where the band edge in the conduction and valence band can be found. Our analysis of the electronic band symmetries helps to better understand several results of recent ab-initio calculations[1,2] for the optical properties of this material. We also calculate the Landau level spectrum. We find that the Landau level spectrum in the degenerate conduction bands at the $\Gamma$ point acquires properties that are reminiscent of the corresponding results in bilayer graphene, but there are important differences as well. Moreover, because of the heavy effective mass, $n$-doped samples may host interesting electron-electron interaction effects.Comment: 10 pages, 5 figure

Molecular dynamics simulation of phase transition of boron nitride single walled nanotube

The melting of zigzag, armchair and chiral single walled boron nitride nanotubes (SWBNs) investigated using molecular dynamics (MD) simulation based on Tersoff-like many body potential. The MD simulation has been employed in the constant pressure, constant temperature (NPT) ensemble. The temperature and pressure of the system were controlled by Nose-Hoover thermostat and Berendsen barostat, respectively. We have computed the variation of the melting temperature with the radius of BN nanotube. The results show that the melting temperature of nanotubes increase with increasing in the size of radii, but this dependence is not the same for the various chiral angle of nanotubes. The relation of the melting point with radius for three types of nanotubes i.e. zigzag, armchair and chiral obtained. Moreover, our results show that the melting temperature of nanotubes approach a constant value at larger radii

Nontrivial tensile behavior of rutile TiO

In this paper, we study the tensile behavior of cylindrical rutile TiO2 nanowires, employing molecular dynamics (MD) simulation technique. The third-generation charge optimized many-body (COMB3) has been used for interatomic potential modeling. The influence of temperature and nanowire diameter on Young’s modulus is investigated. Our simulations exhibit the anisotropic behavior of Young’s modulus as a function of diameter for different crystallographic orientations. Although our results are in good accord with the existing results in [1 0 0] direction, Young’s modulus adds up monotonically with increasing the cross-sectional diameter of nanowire in [0 0 1] direction. It is found that Young’s modulus of the nanowires are lower (higher) than the bulk value for [0 0 1] ([1 0 0]) direction. Furthermore, simulation results also indicate that Young’s modulus of rutile TiO2 nanowire increases as a function of temperature for a given diameter, unexpectedly. The obtained results may be useful in the field of nanotechnology for optimizing mechanical performance to gain specific applications

Stability and thermal behavior of molybdenum disulfide nanotubes: Nonequilibrium molecular dynamics simulation using REBO potential

This study is an attempt to perform equilibrium molecular dynamics and non-equilibrium molecular dynamics (NEMD) to evaluate the stability and thermal behavior of molybdenum disulfide nanotubes (MoS2NTs) by reactive empirical bond order potential. The stability of nanotubes, cohesive energy, isobaric heat capacity, and enthalpies of fusion in armchair and zigzag structures with different radii were calculated. The observed results illustrate that SWMoS2NTs, which have larger diameters, are more stable with more negative energy than the smaller ones. Moreover, it was found that the melting point is increased with an increase in the nanotube\u27s radius. During the melting process, the structural transformation of nanotubes was investigated using a mean-square displacement and radial distribution function diagrams. Afterwards, using a NEMD simulation, the thermal conductivity of nanotubes with various diameters was calculated at a constant nanotube length. The obtained results show that the thermal conductivity coefficient increases with increasing nanotube diameters when the nanotube length is constant

and Epigenetic Dysregulation in Diabetes-prone Bicongenic B6.NODC11bxC1tb Mice

In Type 1 diabetic (T1D) human monocytes, STAT5 aberrantly binds to epigenetic regulatory sites of two proinflammatory genes, CSF2 (encoding granulocyte–macrophage colony-stimulating factor) and PTGS2 (encoding prostaglandin synthase 2/cyclooxygenase 2). Bicongenic B6.NOD C11bxC1tb mice re-create this phenotype of T1D monocytes with only two nonobese diabetic (NOD) Idd subloci (130.8 Mb–149.7 Mb, of Idd5 on Chr 1 and 32.08–53.85 Mb of Idd4.3 on Chr11 ) on C57BL/6 genetic background. These two Idd loci interact through STAT5 binding at upstream regulatory regions affecting Csf2 ( Chr 11 ) and Ptgs2 ( Chr 1 ) expression. B6.NODC11bxC1tb mice exhibited hyperglycemia and immune destruction of pancreatic islets between 8 and 30 weeks of age, with 12%–22% penetrance. Thus, B6.NODC11bxC1tb mice embody NOD epigenetic dysregulation of gene expression in myeloid cells, and this defect appears to be sufficient to impart genetic susceptibility to diabetes in an otherwise genetically nonautoimmune mouse