Hydrothermal synthesis of α-MnO<inf>2</inf> and β-MnO <inf>2</inf> nanorods as high capacity cathode materials for sodium ion batteries

Two types of MnO2 polymorphs, α-MnO2 and β-MnO2 nanorods, have been synthesized by a hydrothermal method. Their crystallographic phases, morphologies, and crystal structures were characterized by XRD, FESEM and TEM analysis. Different exposed crystal planes have been identified by TEM. The electrochemical properties of α-MnO 2 and β-MnO2 nanorods as cathode materials in Na-ion batteries were evaluated by galvanostatic charge/discharge testing. Both α-MnO2 and β-MnO2 nanorods achieved high initial sodium ion storage capacities of 278 mA h g-1 and 298 mA h g-1, respectively. β-MnO2 nanorods exhibited a better electrochemical performance such as good rate capability and cyclability than that of α-MnO2 nanorods, which could be ascribed to a more compact tunnel structure of β-MnO2 nanorods. Furthermore, the one-dimensional architecture of nanorods could also contribute to facile sodium ion diffusion in the charge and discharge process. © The Royal Society of Chemistry 2013

SnO<inf>2</inf>@graphene nanocomposites as anode materials for Na-ion batteries with superior electrochemical performance

An in situ hydrothermal synthesis approach has been developed to prepare SnO2@graphene nanocomposites. The nanocomposites exhibited a high reversible sodium storage capacity of above 700 mA h g-1 and excellent cyclability for Na-ion batteries. In particular, they also demonstrated a good high rate capability for reversible sodium storage. © 2013 The Royal Society of Chemistry

Hydrothermal synthesis of I?-MnO2 and I?-MnO2 nanorods as high capacity cathode materials for sodium ion batteries

Two types of MnO2 polymorphs, I?-MnO2 and I?-MnO2 nanorods, have been synthesized by a hydrothermal method. Their crystallographic phases, morphologies, and crystal structures were characterized by XRD, FESEM and TEM analysis. Different exposed crystal planes have been identified by TEM. The electrochemical properties of I?-MnO2 and I?-MnO2 nanorods as cathode materials in Na-ion batteries were evaluated by galvanostatic charge/discharge testing. Both I?-MnO2 and I?-MnO2 nanorods achieved high initial sodium ion storage capacities of 278 mA h ga??1 and 298 mA h ga??1, respectively. I?-MnO2 nanorods exhibited a better electrochemical performance such as good rate capability and cyclability than that of I?-MnO2 nanorods, which could be ascribed to a more compact tunnel structure of I?-MnO2 nanorods. Furthermore, the one-dimensional architecture of nanorods could also contribute to facile sodium ion diffusion in the charge and discharge process

Effects of shear connectors on plate-reinforced composite coupling beams of short and medium-length spans

Experimental studies on the newly proposed design of plate-reinforced composite (PRC) coupling beams have been carried out. Previous results have demonstrated the useful application of this design in coupling beams of medium span-to-depth ratios (l/h) under both inelastic seismic and elastic wind loading. This paper presents further experimental studies on five PRC coupling beams, which investigated the importance of shear connectors on plate/reinforced concrete composite action. Three medium-length (l/h=2.5) and two short (l/h=1.17) PRC coupling beams, each containing a vertically embedded steel plate, were tested under reversed cyclic loading. While one short beam was welded with expanded metal meshes on the plate surfaces, others were welded with shear studs on the plates in the wall regions and/or the beam spans. Results showed that the expanded metal meshes did not work effectively, and while the shear studs in the beam span only slightly increased the beam capacity, those in the wall regions contributed considerably in improving inelastic beam performance. © 2005 Elsevier Ltd. All rights reserved.postprin

Behaviour of plate anchorage in plate-reinforced composite coupling beams

As a new alternative design, plate-reinforced composite (PRC) coupling beam achieves enhanced strength and ductility by embedding a vertical steel plate into a conventionally reinforced concrete (RC) coupling beam. Based on a non-linear finite element model developed in the authors’ previous study, a parametric study presented in this paper has been carried out to investigate the influence of several key parameters on the overall performance of PRC coupling beams. The effects of steel plate geometry, span-to-depth ratio of beams and steel reinforcement ratios at beam spans and in wall regions are quantified. It is found that the anchorage length of the steel plate is primarily controlled by the span-to-depth ratio of the beam. Based on the numerical results, a design curve is proposed for determining the anchorage length of the steel plate. The load-carrying capacity of short PRC coupling beams with high steel ratio is found to be controlled by the steel ratio of wall piers. The maximum shear stress of PRC coupling beams should be limited to 15 MPa.published_or_final_versio

PCN44 INCIDENCE AND COSTS OF TREATMENT-RELATED COMPLICATIONS AMONG PATIENTS WITH ADVANCED SQUAMOUS CELL CARCINOMA OF THE HEAD AND NECK

Núm. a Art Públic 9008Batlle, Enric; Roig, Joan; Ros Sabaté, Joaqui

Cavitation of Electrons Bubbles in Liquid Helium Below saturation Pressure

We have used a Hartree-type electron-helium potential together with a density functional description of liquid $^4$He and $^3$He to study the explosion of electron bubbles submitted to a negative pressure. The critical pressure at which bubbles explode has been determined as a function of temperature. It has been found that this critical pressure is very close to the pressure at which liquid helium becomes globally unstable in the presence of electrons. It is shown that at high temperatures the capillary model overestimates the critical pressures. We have checked that a commonly used and rather simple electron-helium interaction yields results very similar to those obtained using the more accurate Hartree-type interaction. We have estimated that the crossover temperature for thermal to quantum nucleation of electron bubbles is very low, of the order of 6 mK for $^4$He.Comment: 22 pages, 9 figure

Anyons in a weakly interacting system

We describe a theoretical proposal for a system whose excitations are anyons with the exchange phase pi/4 and charge -e/2, but, remarkably, can be built by filling a set of single-particle states of essentially noninteracting electrons. The system consists of an artificially structured type-II superconducting film adjacent to a 2D electron gas in the integer quantum Hall regime with unit filling fraction. The proposal rests on the observation that a vacancy in an otherwise periodic vortex lattice in the superconductor creates a bound state in the 2DEG with total charge -e/2. A composite of this fractionally charged hole and the missing flux due to the vacancy behaves as an anyon. The proposed setup allows for manipulation of these anyons and could prove useful in various schemes for fault-tolerant topological quantum computation.Comment: 7 pages with 3 figures. For related work and info visit http://www.physics.ubc.ca/~fran

Shigella sonnei genome sequencing and phylogenetic analysis indicate recent global dissemination from Europe

Shigella are human-adapted Escherichia coli that have gained the ability to invade the human gut mucosa and cause dysentery1,2, spreading efficiently via low-dose fecal-oral transmission3,4. Historically, S. sonnei has been predominantly responsible for dysentery in developed countries, but is now emerging as a problem in the developing world, apparently replacing the more diverse S. flexneri in areas undergoing economic development and improvements in water quality4-6. Classical approaches have shown S. sonnei is genetically conserved and clonal7. We report here whole-genome sequencing of 132 globally-distributed isolates. Our phylogenetic analysis shows that the current S. sonnei population descends from a common ancestor that existed less than 500 years ago and has diversified into several distinct lineages with unique characteristics. Our analysis suggests the majority of this diversification occurred in Europe, followed by more recent establishment of local pathogen populations in other continents predominantly due to the pandemic spread of a single, rapidly-evolving, multidrug resistant lineage

Entanglement of spin waves among four quantum memories

Quantum networks are composed of quantum nodes that interact coherently by way of quantum channels and open a broad frontier of scientific opportunities. For example, a quantum network can serve as a `web' for connecting quantum processors for computation and communication, as well as a `simulator' for enabling investigations of quantum critical phenomena arising from interactions among the nodes mediated by the channels. The physical realization of quantum networks generically requires dynamical systems capable of generating and storing entangled states among multiple quantum memories, and of efficiently transferring stored entanglement into quantum channels for distribution across the network. While such capabilities have been demonstrated for diverse bipartite systems (i.e., N=2 quantum systems), entangled states with N > 2 have heretofore not been achieved for quantum interconnects that coherently `clock' multipartite entanglement stored in quantum memories to quantum channels. Here, we demonstrate high-fidelity measurement-induced entanglement stored in four atomic memories; user-controlled, coherent transfer of atomic entanglement to four photonic quantum channels; and the characterization of the full quadripartite entanglement by way of quantum uncertainty relations. Our work thereby provides an important tool for the distribution of multipartite entanglement across quantum networks.Comment: 4 figure