Calculations of Rydberg energy levels for Ni ⅩⅧ using the weakest bound electron potential model theory

Martin expression about the quantum defect of single-valence atoms is extended to many-valence atoms by identifying the weakest bound electron (WBE) under the weakest bound electron potential model(WBEPM) theory. Six Rydberg series energy levels of 2p6np2P°1/2 (n ≥ 3), 2p6np2P°3/2 (n ≥ 3), 2p6nd2D3/2(n ≥ 3), 2p6nd2D5/2 (n ≥ 3), 2p6nf2F°5/2 (n≥4), and 2p6nf2F°7/2 (n ≥ 4) for Ni ⅩⅧ are calculated by this method. The calculated results are in good agreement with the experimental results.     

Measurement of underground motion at the SSRF site

For the Shanghai Synchrotron Radiation Facility (SSRF) and future Shanghai Free‐Electron Laser projects, ground vibration is an important factor and, in order to attenuate it, the construction of a deep tunnel is under consideration. This paper concentrates on the investigation of ground vibration at different underground levels down to 60 m below surface, in order to understand the effect of vibration attenuation with depth. The effect of traffic is also studied using a 10 ton truck, with ground motion compared in different directions. Finally, a summary and some suggestions on these two projects are given.     

Fabrication of oxide base nanostructures using pulsed laser ablation in aqueous solutions

Nanoparticles of TiO₂ and SnO₂ were obtained by laser ablation of Ti and Sn targets in both deionized water and sodium dodecyl sulfate (SDS) solutions. The crystallinity of the nanoparticles strongly depended on the SDS concentration in the solution. Well-crystallized oxide nanoparticles were most abundantly fabricated in SDS solution with around the critical micelle concentration. An inorganic/organic layered nanocomposite consisting of a zinc hydroxide layer and a SDS lamellar interlayer was obtained by the ablation of Zn in SDS solutions. The oxide and/or hydroxide can be formed by the rapid reactive quenching with water in the liquid–plasma interface, where ablated species can be oxidized by aqueous oxidation. The surfactant in the liquid medium could affect the aggregation and growth of nuclei after the oxidation. The preparation of Pt/TiO₂ nanocomposite particles by PLA of the bi-combinant target of Pt and TiO₂ is also reported. PACS 81.16.Mk; 81.10.Dn; 81.07.Bc     

Improvement of intelligibility of ideal binary-masked noisy speech by adding background noise

When a target-speech/masker mixture is processed with the signal-separation technique, ideal binary mask (IBM), intelligibility of target speech is remarkably improved in both normal-hearing listeners and hearing-impaired listeners. Intelligibility of speech can also be improved by filling in speech gaps with un-modulated broadband noise. This study investigated whether intelligibility of target speech in the IBM-treated target-speech/masker mixture can be further improved by adding a broadband-noise background. The results of this study show that following the IBM manipulation, which remarkably released target speech from speech-spectrum noise, foreign-speech, or native-speech masking (experiment 1), adding a broadband-noise background with the signal-to-noise ratio no less than 4 dB significantly improved intelligibility of target speech when the masker was either noise (experiment 2) or speech (experiment 3). The results suggest that since adding the noise background shallows the areas of silence in the time-frequency domain of the IBM-treated target-speech/masker mixture, the abruption of transient changes in the mixture is smoothed and the perceived continuity of target-speech components becomes enhanced, leading to improved target-speech intelligibility. The findings are useful for advancing computational auditory scene analysis, hearing-aid/cochlear-implant designs, and understanding of speech perception under "cocktail-party" conditions.     

Morphology and elemental behaviour in the alteration layer of borosilicate glass in simulated groundwater

To understand the behaviour of nuclear waste glass in groundwater, borosilicate glasses were placed in simulated groundwater for more than 200 days. The composition of the simulated groundwater was similar to that of the groundwater in Beishan (a potential nuclear waste site). The pH value of groundwater was adjusted to 7.5, and the ratio of the surface area of glass to the volume of the solution (SA/V) was set to 10?m^?1. Solutions and bulk glasses were characterised to obtain the elemental behaviour and surface morphology of the glass/solution interface, which was named the alteration layer. The mean thicknesses of the alteration layer were 5.16?±?0.11?µm and 11.67?±?0.28?µm at 70°C and 90°C, respectively. A thicker alteration layer was attributed to the lower surface activation energy of the glass and a high ion exchange between K⁺ and Na⁺ in the interface between the glass surface and the solution. For the elemental behaviour, mobile species B and Na were depleted, while K and Ca from the solution were enriched in the alteration layer due to ion exchange. Network species Si decreased in the layer, leading to the corrosion of the backbone of the glass; however, species Al increased, which implied that some [SiO₄] units were partially replaced by [AlO₄] units. In this work, glass in groundwater suffered much more intense corrosion than that in de-ionised water.     

Insulator, semiclassical oscillations and quantum Hall liquids at low magnetic fields

Magneto-transport measurements are performed on two-dimensional GaAs electron systems to probe the quantum Hall (QH) effect at low magnetic fields. Oscillations following the Shubnikov-de Haas (SdH) formula are observed in the transition from the insulator to QH liquid when the observed almost temperature-independent Hall slope indicates insignificant interaction correction. Our study shows that the existence of SdH oscillations in such a transition can be understood based on the non-interacting model.     

Low‐temperature Extensions of the Virial Equation of State for Solar Modeling

Low‐order density expansions cannot adequately describe recombination reactions. Therefore, the usefulness of an exact quantum virial expansion truncated at the order of ?^5/2 is limited to the deeper interior of the Sun, where the plasma is nearly fully ionized. Here, intermediate steps towards full‐fledged solar modeling are presented. They are (i) a smooth numerical representation of the quantum virial expansion and (ii) the construction of a smooth transition to the low‐temperature regime (below 50,000 K), where the virial expansions breaks down due to H recombination. These technical steps are realized for a simplified H‐only plasma; the extension to He and heavier elements will be dealt with later. Ultimately, the outcome will be that solar observations can be used to test the accuracy of the virial equation of state and to compare it with current more phenomenological formalisms (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nonlinear optical switching matrix

We show that nonlinear directional couplers with variable coupling coefficients can be used to compose a special kind of switching matrix. The switching matrix can be controlled by the signal itself or by a strong pump. Light routing is realized by adjustment of the power of the signal or the pump. Because light routing is based on the optical Kerr effect, ultrafast routing is possible.     

Influence of interface roughness on reflectivity of tungsten/boron-carbide multilayers with variable hi-layer number by X-ray reflection and diffuse scattering

from layer to layer during multilayer growing. The variation of the reflectivity and interface roughness with bi-layer number is accurately explained by the presented real-structure model.     

Charge Hall effect generated by spin-polarized current injected into Rashba spin orbit coupling media

Using the Keldysh Green’s function method, we study theoretically the electron accumulation induced by the inverse spin Hall effect in a spin valve structure in which a clean quantum wire formed from a 2D electron gas (2DEG) with Rashba/Dresselahaus spin orbit interaction (SOI) is connected to two ferromagnet electrodes. In a nonequilibrium situation when a spin current with an out-of plane (the 2DEG plane) spin polarization is driven through the SOI region by an external voltage, non-equilibrium electron accumulation or a Hall voltage forms at the two lateral sides of the quantum wire and exhibits an oscillation along the wire like the Rashba spin precession; the magnetization directions of FMs affect the Hall voltage and their parallel or antiparallel alignment along the normal direction of the 2DEG plane is most favorable to the Hall voltage. In an equilibrium situation, two planar magnetizations which are not collinear can generate an electron accumulation/a Hall voltage too. When one of the FM electrodes is replaced by a normal metal (NM), the electron accumulation is still present along the wire and its magnitude remains nearly unchanged in the biased case, whereas in the unbiased case it is reduced significantly and even vanishes.