Equilibrium faceting formation in vicinal Al2O3 (0001) surface caused by annealing

We report on a heat-induced transformation of the surface of α-alumina (0001) crystals which have an off-cut in the [1$\overline{2}$10] direction. Annealing the crystal causes the surface to transform into a regular array of (0001) and (1$\overline{2}$16) facets. The resultant faceted morphology represents the equilibrium state of the system. It is demonstrated that the average terrace periodicity is determined by the annealing temperature. Possible causes for the surface rearrangement are also discussed. This method could be used for producing templates with controlled periodicity for growth of nanostructure arrays.     

Temperature effects in five-dimensional Kaluza-Klein theory

We examine the combined effectsof thermal and quantum-mechanical fluctuations in a Kaluza-Klein universe with a single compact spatial dimension of length ${\overline{L}}_5$. From the one-loop effective potential for ${\overline{L}}_5$ two types of instability are evident. If initially ${\overline{L}}_5$ is less than a temperature-dependent critical length, ${\overline{L}}_5$ will shrink at least down to a length comparable to the Planck length. This instability has been noted by Appelquist and Chodos in the zero-temperature limit. If, on the other hand, ${\overline{L}}_5$ starts out larger than the critical length, it will tend to increase. This result suggests that temperature effects may play an important role in Kaluza-Klein cosmological models.     

Orientation relationship between α-Fe precipitate and α-Al2O3 matrix in iron-implanted sapphire

Fe ions were implanted into α-Al₂O₃ single crystals (sapphire) at room temperature and annealed in a reducing atmosphere. The orientation relationships (ORs) between α-Fe particles and sapphire matrix were investigated using transmission electron microscopy (TEM). All the α-Fe particles have the orientation relationship (OR) of (1 1 1)_α-Fe || (0 0 0 1)_sapphire and ${[1\overline{1}0]}_{\alpha \text{-Fe}}\left|\right|{[11\overline{2}0]}_{\text{sapphire}}$ with sapphire. This OR is predicted precisely by the coincidence of reciprocal lattice points (CRLP) method. The other OR of (1 1 0)_α-Fe || (0 0 0 1)_sapphire and ${[111]}_{\alpha \text{-Fe}}\left|\right|{[5\overline{1}\overline{4}0]}_{\text{sapphire}}$ reported before is confirmed by the same method to be one of the secondary preferred orientation relationships in the α-Fe/sapphire system.     

Investigation of structural and electronic properties of β- HgS: Molecular dynamics simulations

The pressure induced phase transition of β-HgS is studied using an ab initio molecular dynamics simulation. The structural phase transformation from the zinc-blende structure to the NaCl-type structure (space group $Fm\overline{3}m$) and from this structure to CsCl-type structure ($Pm\overline{3}m$) with the application of hydrostatic pressure is predicted. Additionally, the electronic properties of HgS and various physical properties such as the lattice constants, the bulk modulus and the pressure derivative of the bulk modulus are revealed. Furthermore, these phase transitions are obtained using the total energy and enthalpy calculations. According to these calculations these transformations are occurring at about 20?GPa and 28?GPa for $F\overline{4}3m$ →$Fm\overline{3}m$ and $Fm\overline{3}m$ →$Pm\overline{3}m$, respectively.     

Measurement of the top quark pair production cross section in pp collisions at s=7TeV in dilepton final states with ATLAS

A measurement of the production cross section of top quark pairs ($t\overline{t}$) in proton–proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider is reported. Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. Using a data sample corresponding to an integrated luminosity of $35{\mathrm{pb}}^{?1}$, a $t\overline{t}$ production cross section ${\sigma }_{t\overline{t}}=177\pm 20(\text{stat.})\pm 14(\text{syst.})\pm 7(\text{lum.})\text{pb}$ is measured for an assumed top quark mass of $m_t=172.5\text{GeV}$. A second measurement requiring at least one jet identified as coming from a b quark yields a comparable result, demonstrating that the dilepton final states are consistent with being accompanied by b-quark jets. These measurements are in good agreement with Standard Model predictions.     

Electron energy-loss spectroscopy from polar ZnO surfaces

Reflection electron energy-loss spectra (ELS) in the 2–30-eV range were obtained from ZnO ($000\overline{1}$)O and (0001)Zn faces. Measurements were performed on atomically clean surfaces and on surfaces subjected to different treatments, including exposures to atomic hydrogen and molecular oxygen. The spectra were compared with ELS, UPS, XPS and UV reflection results obtained by other investigators. An identification of the observed electronic transitions is attempted.     

Primordial quantum chromodynamics: QCD of a Fermi-Bose couple of coloured preons

We consider QCD of a massive Fermi-Bose couple of two colour triplets δ and χ of spin 1/2 and 0, respectively, and of equal charge ? 1/3, interacting with a colour octet of gluons. We conjecture that leptons and quarks of the lowest generation are bound states ${\nu }_e=\delta \overline{\chi },e=\delta (\chi \chi )P$ and $u=\overline{\delta }\overline{\chi },d=\overline{\delta }(\chi \chi )P$.