We investigate the equation of states of the $beta$-polymorph of cyclotetramethylene tetranitramine (HMX) energetic molecular crystal using DFT-D2, a first-principles calculation based on density functional theory (DFT) with van der Waals (vdW) corre
ctions. The atomic structures and equation of states under hydrostatic compressions are studied for pressures up to 100 GPa. We found that the N-N bonds along the minor axis of the ring are more sensitive to the variation of pressure, which indicates that they are potential weak spots in atomic level within a single molecule of $beta$-HMX. Our study suggested that the van der Waals interactions are critically important in modeling this molecular crystal.
We introduced a method to obtain the continuum description of the elastic properties of mono- layer h-BN through ab initio density functional theory. This thermodynamically rigorous contin- uum description of the elastic response is formulated by exp
anding the elastic strain energy density in a Taylor series in strain truncated after the fifth-order term. we obtained a total of fourteen nonzero independent elastic constants for the up to tenth-order tensor. We predicted the pressure dependent second-order elastic moduli. This continuum formulation is suitable for incorporation into the finite element method.
Recently hybridized monolayers consisting of hexagonal boron nitride (h-BN) phases inside graphene layer have been synthesized and shown to be an effective way of opening band gap in graphene monolayers [1]. In this letter, we report an ab initio den
sity functional theory (DFT)- based study of h-BN domain size effect on the elastic properties of graphene/boron nitride hybrid monolayers (h-BNC). We found both inplane stiffness and longitudinal sound velocity of h-BNC linearly decrease with h-BN concentration.
Bandgap engineering by substituting C with B and N atoms in graphene has been shown to be a promising way to improve semiconducting properties of graphene. Such hybridized monolayers consisting of hexagonal BN phases in graphene (h-BNC) have been rec
ently synthesized and char- acterized. In this paper, we present an ab initio density functional theory (DFT)-based study of h-BN domain size effect on band gap of mono-layer h-BNC heterostructures. The atomic structures, electronic band structures, density of states and electron localization functions of five h-BNC config- urations are examined as h-BN concentration ranged from 0 to 100%. We report that the band gap energy of h-BNC can be continuously and quadratically tuned as a function of h-BN concentration.
In our work: 0903.2612, we calculate the production rate of single top-Higgs boson in the TC2 model which is a modified version of the original top-technicolor model. The similar process was discussed in arXiv:hep-ph/9905347v2. The TC2 model, as we d
iscussed in the introduction part remedies some shortcomings and loophole of the old version. The top-Higgs in the TC2 model is a mixture of the top-Higgs of the toptechnicolor model and that of the ETC model, thus a parameter $epsilon$ is introduced to denote the mixture. Moreover, we vary the mass range of the top-Higgs within 300 to 800 GeV while in arXiv:hep-ph/9905347v2, the mass range was taken as 200 to 400 GeV. In the work, our numerical results show that the production rate of single top-Higgs in the TC2 model is very close to that in the toptecnicolor model within the mass range of 200 to 400 GeV. This manifests that change from the original toptechnicolor model to the new TC2 version does not much affect the production rate of the top-Higgs even though the two top-Higgs in the two models are different. Beyond the 400 GeV, even the TC2 model predicts a negligible production rate at LHC. Since the phenomenological change is indeed not obvious, there is not much new to report. Even though the two models are somehow different, we believe that the result is not worth publishing. Therefore we decide to withdraw our manuscript.
As well known, if the Higgs boson were not observed at LHC, the technicolor model would be the most favorable candidate responsible for the symmetry breaking. To overcome some defects in the previous model, some extende
