[en] An algorithm for evaluating Slater integrals in a B-spline basis is introduced. Based on the piecewise property of the B-splines, the algorithm divides the two-dimensional (r₁, r₂) region into a number of rectangular cells according to the chosen grid and implements the two-dimensional integration over each individual cell using Gaussian quadrature. Over the off-diagonal cells, the integrands are separable so that each two-dimensional cell-integral is reduced to a product of two one-dimensional integrals. Furthermore, the scaling invariance of the B-splines in the logarithmic region of the chosen grid is fully exploited such that only some of the cell integrations need to be implemented. The values of given Slater integrals are obtained by assembling the cell integrals. This algorithm significantly improves the efficiency and accuracy of the traditional method that relies on the solution of differential equations and renders the B-spline method more effective when applied to multi-electron atomic systems

[en] Inelastic neutron scattering is used to characterize spin fluctuations in the d -electron heavy fermion spinel LiV₂O ₄ . The spin-relaxation rate, Γ_Q , for Q=0.6 {angstrom}^-1 is 1.4(2)meV at low temperatures and increases linearly with temperature at a rate of 0.46(8)k_B . There is antiferromagnetic short-range order at low temperatures with a characteristic wave vector Q_c=0.64(2) {angstrom}^-1 and a correlation length of 6(1) {angstrom} . While warming shifts intensity towards lower Q , the staggered susceptibility peaks at a finite wave vector for T<80 K . The data are compared with conventional heavy fermion systems, geometrically frustrated insulating magnets, and recent theories for LiV₂O ₄

[en] The modulation in Pendellosung fringe visibility in perfect crystal is due to the interference between σ and π polarization states of X-ray wave. It is stimulated by superposition of two polarization states by computer based on spherical X-ray wave dynamical theory and compared with fringe pattern on X-ray diffraction section topograph. It is found that the agreement between experimental result and theoretical calculation is satisfactory

[en] A SHRIMP U-Pb in zircon age of a syn- to late- gold mineralization pegmatite dyke from a granulite-hosted lode-gold deposit at Griffin's Find Western Australia, provides a minimum age constraint on gold mineralization of 2632±3 Ma. A nearby syenogranite has an indistinguishable SHRIMP U-Pb in zircon age of 2636±10 Ma. These age constraints are within error of a previously published age of 2636±3 Ma for gold mineralization and peak metamorphism at Griffin's Find, determined by a Pb-Pb isochron for ore and alteration minerals, and similar to a U-Pb in zircon age of 2640±1 Ma for peak metamorphism. This age is also compatible with that of other age determinations on gold mineralization from lower metamorphic-grade settings elsewhere in the Yilgarn Craton. A minimum age of 2669±36 (σ) Ma, determined by a concordant analysis on an inherited zircon core by SHRIMP II, is suggested for the source rock of the pegmatite dykes. Two other analyses, which yield ²⁰⁷Pb/²⁰⁶Pb ages of 2676±20 and 2660±20 Ma with 77-92% concordance, support the presence of an old inherited component in the source of the pegmatite magma A Pb-Pb isochron, comprising two whole-rock and two K-feldspar analyses for samples from the granite, gives a precise age of 2680±6 Ma, which is tentatively interpreted to reflect an old inherited component in a ca. 2636 Ma felsic intrusion. The geochronological results detailed in this study, together with previous data, suggest the emplacement of a regional granitic batholith in high-grade metamorphic settings at the time of fold mineralization. (authors)

[en] We report here the first use of ion beams in the electronic stopping region to improve the adhesion of insulators to other materials. In particular, we have dramatically improved the bonding of Au films to teflon, ferrite, and SiO₂ by bombarding them with He and Cl, respectively. Improvements in bonding have also been observed for Au on glass, Au and Cu on sapphire, and Si₃N₄ on Si. The mechanism is apparently associated with sputtering and track-forming processes occuring in the electronic stopping region. Numerous applications are discussed. (orig.)

[en] Ta/Al periodic multilayer films with a modulation wavelength of 4.54 nm are fabricated by magnetron sputtering. The structural change and the thermal stability of the films after annealing at different temperatures up to 1000 ⁰C are studied by X-ray diffraction. From the X-ray diffraction results, a new modulation period is found after the annealing, which is larger than original one by 25% at least. During the initial stage of annealing, the new and the original periods coexist in the same sample. As the annealing temperature is raised to 600 ⁰C, a stable sandwich structure only with the new modulation period is formed, the reflectivity of which is as strong as the original one. This anomalous phenomenon is believed to arise from the formation of a TaAl₃ β-phase in the interface regions due to the solid state reaction. (author)

[en] Because of recent interest in the role played by the thermal properties of materials that exhibit high energy sputtering, we have sputtered Al₂O₃ and LiNbO₃ with chlorine ions at energies between 3 MeV and 25 MeV. To detect the sputtered Al and Nb we employ thin carbon catcher foils, which are analyzed with Rutherford scattering in the forward direction. Al surface densities of 10¹⁴/cm² and Nb surface densities of 10¹³/cm² are easily measured. The sputtering yields for both Al₂O₃ and LiNbO₃ increase rapidly with increasing chlorine energy, and the Al and Nb yields are both approximately 0.2 at 20 MeV. Tests for dose, beam current, and contamination effects will be discussed. (author)

[en] The atmospheric pressure glow discharge (APGD) is more promising in industrial applications compared with glow discharges in a gas other than air or in low-pressure air, which needs an expensive vacuum system. In this paper, the APGD and dielectric barrier discharge (DBD) are generated in atmospheric air using a power-frequency voltage source, and the transition from DBD to APGD is achieved by varying the electrode arrangement. The differences between their discharge characteristics are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena. The effects of APGD and DBD on polytetrafluoroethylene (PTFE) surface modification are studied. The surface properties are characterized by contact angle measurement, x-ray photoelectron spectroscopy and scanning electron microscopy. It is found that the APGD and DBD treatments modify the PTFE surface in both morphology and composition. APGD is more effective in PTFE surface modification than DBD as it can modify the surface more uniformly, implant more oxygen atoms into the surface and make the contact angle decline to a lower level. The experimental results are discussed

[en] Monte Carlo simulations containing a large number of tallies generally suffer severe performance penalties due to a significant amount of run time spent in searching for and scoring individual tally bins. This paper describes the improved methods of handling large numbers of tallies, which have been implemented in the RMC Monte Carlo code. The calculation results demonstrate that the proposed methods can considerably improve the tally performance when massive tallies are treated. In the calculated case with 6 million of tally regions, only 10% of run time is increased in each active cycle against each inactive cycle. (authors)

[en] We have sputtered silicon, silicon dioxide, and silicon nitride with chlorine ions at 5 MeV and 20 MeV. While the yield from the silicon target was unmeasurably low, the insulating compounds exhibited the enhanced yields observed in other insulating targets. The yield follows the electronic stopping power and seems to be independent of the target's thermal properties. Some of the data suggest that the enhanced sputtering mechanism may be active in extremely thin films (=> 3 mono-layers). (author)