Modification of terminating species and band alignment at the interface between alumina films and metal single crystals

Thin epitaxial alumina films were grown on Cu(111), Cu–9 at.%Al(111), Ni(111) and NiAl(110) single crystals. The alumina films grew in such a manner that hexagonal or pseudo-hexagonal oxygen lattices were parallel to the surface of the substrates. Photoelectron spectra were obtained either with synchrotron or Al K-alpha radiation. We measured Al 2p spectra and determined the atomic species that terminated the interface between the alumina films and the substrates. The influence of Al in the substrates on the species that terminated the interface has been discussed based on thermodynamics. From valence band spectra, p-type Schottky barrier height (energy difference between the Fermi level of the metallic substrates and the valence band maximum of the alumina films, band offset) was determined. Differences in interface terminating species resulted in variations in p-type Schottky barrier height, or band alignment.     

Q values of the Ge and Mo double-beta decays

Penning trap measurements using mixed beams of ⁷⁶Ge–⁷⁶Se and ¹⁰⁰Mo–¹⁰⁰Ru have been utilized to determine the double-beta decay Q-values of ⁷⁶Ge and ¹⁰⁰Mo with uncertainties less than 200 eV. The value for ⁷⁶Ge, 2039.04(16) keV is in agreement with the published SMILETRAP value, 2039.006(50) keV. The new value for ¹⁰⁰Mo, 3034.40(17) keV is 30 times more precise than the previous literature value, sufficient for the ongoing neutrinoless double-beta decay searches in ¹⁰⁰Mo. Moreover, the precise Q-value is used to calculate the phase-space integrals and the experimental nuclear matrix element of double-beta decay.     

Bioactive borate glass scaffold for bone tissue engineering

Borate glass particles and microspheres with size distributions in the range of approximately 100–400 μm, were loosely compacted and sintered for 10 min at 600 °C to form a porous, three-dimensional construct (porosity 25–40%). Conversion of the borate glass to hydroxyapatite was investigated by soaking the constructs in a solution of K₂HPO₄ (0.25 M) at 37 °C and with a pH value of 9.0, and measuring the weight loss of the constructs as a function of time. Almost full conversion of the borate glass to hydroxyapatite was achieved in less than 6 days. X-ray diffraction revealed an initially amorphous product that subsequently crystallized to hydroxyapatite. The biocompatibility of the porous constructs was investigated by in vitro cell culture with human mesenchymal stem cells derived from bone marrow (bMSC) and human mesenchymal stem cell derived osteoblasts (MSC-Ob). The cells adhered to the scaffolds and the MSC-Obs produced alkaline phosphatase which is an indication of osteogenic differentiation. The data suggest strong bioactive characteristics for the borate glass constructs and the potential use of the constructs as scaffolds for tissue engineering of bone.     

Structure oftrans-methyl 2-phenylhexahydro-2H-isoxazolo (2,3-a)-pyridine-3-carboxylate

The title compound, a 1,3-dipolar cycloaddition product, crystallizes in the monoclinic space groupP2₁/c, witha=8.199(3),b=16.908(1),c=10.248(2)Å,=93.58(2)° andZ=4. The structure was solved by direct methods and refined by full matrix least squares methods toR=0.038 for 1687 observed reflections. The stereochemistry of this compound was found to have the ee conformation in the solid state as well as in solution. The piperidine ring in the molecule is in the chair form and the isoxazolidine ring adopts an envelope conformation.     

The electronic structure and adsorption geometry of L-histidine on Cu(110)

The adsorption of L-histidine on clean and oxygen-covered Cu(110) surfaces has been studied by soft X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The valence band spectra, carbon, nitrogen and oxygen 1 s XPS and N K edge absorption spectra were measured for submonolayer, monolayer, and multilayer films. The spectra provide a detailed picture of the electronic structure and adsorption geometry at each coverage. In the monolayer, the histidine molecules are randomly oriented, in contrast to the submonolayer regime, where the molecules are coordinated to the copper surface with the imidazole functional group nearly parallel to, and strongly interacting with, the surface. The pi*/sigma* intensity ratio in NEXAFS spectra at the nitrogen edge varies strongly with angle, showing the imidazole ring is oriented. Adsorption models are proposed.     

Bounds for Eigenvalues of Matrix Polynomials Over Quaternion Division Algebra

Localization theorems are discussed for the left and right eigenvalues of block quaternionic matrices. Basic definitions of the left and right eigenvalues of quaternionic matrices are extended to quaternionic matrix polynomials. Furthermore, bounds on the absolute values of the left and right eigenvalues of quaternionic matrix polynomials are devised and illustrated for the matrix p norm, where \({p = 1, 2, \infty, F}\). The above generalizes the bounds on the absolute values of the eigenvalues of complex matrix polynomials, which give sharper bounds to the bounds developed in [LAA, 358, pp. 5–22 2003] for the case of 1, 2, and \({\infty}\) matrix norms.     

Prompt gamma-ray analysis (PGA) of meteorite samples, with emphasis on the determination of Si

Neutron-induced prompt gamma-ray analysis (PGA) was applied to seven meteorite samples (Allende, Zagami, Acfer 209, ALH77005, ALH84001, EET79001 and Neagari). Samples were irradiated in both the thermal neutron and the cold neutron guided beams of JRR-3M at JAERI. Multiple samples of an Allende standard powder were analyzed for Si using two different methods: (1) the comparison method, using a Si standard, and (2) the mono-standard method, using Fe as an internal reference element. The Si concentrations determined by these two methods are in good agreement with literature values. The analytical sensitivity for Si using the cold neutron guided beam is∼14.3× higher than that for the thermal neutron guided beam. Other elements determined (B, Ca, Ti and S) also showed higher sensitivities using the cold neutron beam. The other meteorites studied showed some anomalous B and S values likely due to the effects of terrestrial weathering/contamination.     

Exact interior solutions in 2+1-dimensional spacetime

An exact formulation of two-dimensional chiral hydrodynamics with diffeomorphism and conformal anomalies is provided. The constitutive relation involving the stress tensor is computed. It reveals a one parameter class of solutions which is a new result. For a particular value of this parameter, the results found in the gradient expansion scheme are reproduced. Moreover, the constitutive relation is analogous to the corresponding relation for an ideal fluid, appropriately modified to include the chirality property, which has also been derived here.     

Exact Solution of a(2+1)-Dimensional Anisotropic Star in Finch and Skea Spacetime

We provide a new class of interior solution of a(2+1)-dimensional anisotropic star in Finch and Skea spacetime corresponding to the BTZ black hole. We develop the model by considering the MIT bag model EOS and a particular ansatz for the metric function grrproposed by Finch and Skea [M.R. Finch and J.E.F. Skea, Class. Quantum.Grav. 6(1989) 467]. Our model is free from central singularity and satisfies all the physical requirements for the acceptability of the model.