bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarizable molecular interactions in condensed phase and their equivalent nonpolarizable models
Authors: Leontyev Igor V. , Stuchebrukhov Alexei A.
Published: July 2014

Earlier, using phenomenological approach, we showed that in some cases polarizable models of condensed phase systems can be reduced to nonpolarizable equivalent models with scaled charges. Examples of such systems include ionic liquids, TIPnP-type models of water, protein force fields, and others, where interactions and dynamics of inherently polarizable species can be accurately described by nonpolarizable models. To describe electrostatic interactions, the effective charges of simple ionic liquids are obtained by scaling the actual charges of ions by a factor of $1/\sqrt {\varepsilon _{el} }$1/ɛel, which is due to electronic polarization screening effect; the scaling factor of neutral species is more complicated. Here, using several theoretical models, we examine how exactly the scaling factors appear in theory, and how, and under what conditions, polarizable Hamiltonians are reduced to nonpolarizable ones. These models allow one to trace the origin of the scaling factors, determine their values, and obtain important insights on the nature of polarizable interactions in condensed matter systems.
In-situ neutron diffraction of LaCoO3 perovskite under uniaxial compression. I. Crystal structure analysis and texture development
Authors: Aman Amjad , Chen Yan , Lugovy Mykola , Orlovskaya Nina , Reece Michael J. , Ma Dong , Stoica Alexandru D. , An Ke
Published: July 2014

The dynamics of texture formation, changes in crystal structure, and stress accommodation mechanisms have been studied in perovskite-type R3¯c rhombohedral LaCoO3 during uniaxial compression using in-situ neutron diffraction. The in-situ neutron diffraction revealed the complex crystallographic changes causing the texture formation and significant straining along certain crystallographic directions during compression, which are responsible for the appearance of hysteresis and non-linear ferroelastic deformation in the LaCoO3 perovskite. The irreversible strain after the first loading was connected with the appearance of non-recoverable changes in the intensity ratio of certain crystallographic peaks, causing non-reversible texture formation. However, in the second loading/unloading cycle, the hysteresis loop was closed and no further irrecoverable strain appeared after deformation. The significant texture formation is responsible for an increase in the Young's modulus of LaCoO3 at high compressive stresses, ranging from 76 GPa at the very beginning of the loading to 194 GPa at 900 MPa at the beginning of the unloading curve.
High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness
Authors: Vivek A. , Hansen S. R. , Daehn Glenn S.
Published: July 2014

Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-based analytical model was developed and found to have reasonable agreement with experiment.
Rectification induced in N2AA-doped armchair graphene nanoribbon device
Authors: Chen Tong , Li Xiao-Fei , Wang Ling-Ling , Luo Kai-Wu , Xu Liang
Published: July 2014

By using non-equilibrium Green function formalism in combination with density functional theory, we investigated the electronic transport properties of armchair graphene nanoribbon devices in which one lead is undoped and the other is N2AA-doped with two quasi-adjacent substitutional nitrogen atoms incorporating pairs of neighboring carbon atoms in the same sublattice A. Two kinds of N2AA-doped style are considered, for N dopants substitute the center or the edge carbon atoms. Our results show that the rectification behavior with a large rectifying ratio can be found in these devices and the rectifying characteristics can be modulated by changing the width of graphene nanoribbons or the position of the N2AA dopant. The mechanisms are revealed to explain the rectifying behaviors.
Continuous ultra-thin MoS2 films grown by low-temperature physical vapor deposition
Authors: Muratore C. , Hu J. J. , Wang B. , Haque M. A. , Bultman J. E. , Jespersen M. L. , Shamberger P. J. , McConney M. E. , Naguy R. D. , Voevodin A. A.
Published: July 2014

Uniform growth of pristine two dimensional (2D) materials over large areas at lower temperatures without sacrifice of their unique physical properties is a critical pre-requisite for seamless integration of next-generation van der Waals heterostructures into functional devices. This Letter describes a vapor phase growth technique for precisely controlled synthesis of continuous, uniform molecular layers of MoS2 on silicon dioxide and highly oriented pyrolitic graphite substrates of over several square centimeters at 350 °C. Synthesis of few-layer MoS2 in this ultra-high vacuum physical vapor deposition process yields materials with key optical and electronic properties identical to exfoliated layers. The films are composed of nano-scale domains with strong chemical binding between domain boundaries, allowing lift-off from the substrate and electronic transport measurements from contacts with separation on the order of centimeters.
Experimental study on the oxide trap coupling effect in metal oxide semiconductor field effect transistors with HfO2 gate dielectrics
Authors: Ren Pengpeng , Wang Runsheng , Jiang Xiaobo , Qiu Yingxin , Liu Changze , Huang Ru
Published: July 2014

In this Letter, the coupling effect between multi-traps in HfO2 gate dielectrics is experimentally studied in scaled high-κ/metal-gate metal oxide semiconductor field effect transistors (MOSFETs). Deviated from conventional understanding, mechanism that affects trap coupling is found, which is originated from local carrier density perturbation due to random dopant fluctuation (RDF) in the channel. The competition of conventional Coulomb repulsion effect and RDF induced local carrier density perturbation effect results in the nonmonotonic voltage dependence of trap coupling intensity.
On geometric factors for neutral particle analyzers
Authors: Stagner L. , Heidbrink W. W.
Published: July 2014

Neutral particle analyzers (NPA) detect neutralized energetic particles that escape from plasmas. Geometric factors relate the counting rate of the detectors to the intensity of the particle source. Accurate geometric factors enable quick simulation of geometric effects without the need to resort to slower Monte Carlo methods. Previously derived expressions [G. R. Thomas and D. M. Willis, “Analytical derivation of the geometric factor of a particle detector having circular or rectangular geometry,” J. Phys. E: Sci. Instrum. 5(3), 260 (1972); J. D. Sullivan, “Geometric factor and directional response of single and multi-element particle telescopes,” Nucl. Instrum. Methods 95(1), 5–11 (1971)] for the geometric factor implicitly assume that the particle source is very far away from the detector (far-field); this excludes applications close to the detector (near-field). The far-field assumption does not hold in most fusion applications of NPA detectors. We derive, from probability theory, a generalized framework for deriving geometric factors that are valid for both near and far-field applications as well as for non-isotropic sources and nonlinear particle trajectories.
Design and operation of a fast electromagnetic inductive massive gas injection valve for NSTX-U
Authors: Raman R. , Jarboe T. R. , Nelson B. A. , Gerhardt S. P. , Lay W.-S. , Plunkett G. J.
Published: July 2014

Results from the operation of an electromagnetic valve, that does not incorporate ferromagnetic materials, are presented. Image currents induced on a conducting disc placed near a pancake solenoid cause it to move away from the solenoid and open the vacuum seal. A new and important design feature is the use of Lip Seals for the sliding piston. The pressure rise in the test chamber is measured directly using a fast time response Baratron gauge. The valve injects over 200 Torr l of nitrogen in less than 3 ms, which remains unchanged at moderate magnetic fields.
Single-component single-partial acoustic surface waves in cubic crystals with surface distortion taken into account
Authors: Klochko M. S.
Published: July 2014

The surface waves and bulk acoustic bands were studied taking into account the interaction between the nearest and next-nearest neighbors in a cubic crystal. Expressions for the dispersion relations, the frequencies at which the surface waves split off the bulk spectrum, and the parameters of the amplitude attenuation have been obtained for the crystalline systems in which the surface waves are single-component and single-partial. The calculations were conducted taking into account the discrete nature of crystal lattice for arbitrary values of the two-dimensional wave vector. The analysis has demonstrated that the results obtained in the long-wavelength limit are in full agreement with those calculated in the framework of linear nonlocal elasticity theory. The influence of an adsorbed surface monolayer on the characteristics of the surface waves was studied.
Quantum paraelectric glass state in SrCu3Ti4O12
Authors: Kumar Jitender , Choudhary Ram Janay , Awasthi A. M.
Published: July 2014

Magnetic and dielectric studies of SrCu3Ti4O12 carried out over 5–300 K confirm antiferromagnetic (AFM) ordering of Cu-spins at TN = 23 K. Dielectric constant ε′ measured across 1 Hz-1 MHz signifies quantum paraelectric character, Barrett-fittable almost down to TN. Competition of athermal fluctuations and the literature-reported magneto-phonon-softening near TN manifest a quantum paraelectric glass (QPG) state. Emergent AFM-field tunes the otherwise quantum ordering (at absolute-zero) of the dipoles to finite-temperature kinetic glass transition; spectral dispersion of dielectric constant was unambiguously manifested and characterized. Vogel-Fulcher glass-kinetics parameterization sets the almost relaxation-free QPG state in SrCu3Ti4O12 apart from an emergent scaling-class, to which typical ferroelectric relaxors belong.
Collisionless Weibel shocks: Full formation mechanism and timing
Authors: Bret A. , Stockem A. , Narayan R. , Silva L. O.
Published: July 2014

Collisionless shocks in plasmas play an important role in space physics (Earth's bow shock) and astrophysics (supernova remnants, relativistic jets, gamma-ray bursts, high energy cosmic rays). While the formation of a fluid shock through the steepening of a large amplitude sound wave has been understood for long, there is currently no detailed picture of the mechanism responsible for the formation of a collisionless shock. We unravel the physical mechanism at work and show that an electromagnetic Weibel shock always forms when two relativistic collisionless, initially unmagnetized, plasma shells encounter. The predicted shock formation time is in good agreement with 2D and 3D particle-in-cell simulations of counterstreaming pair plasmas. By predicting the shock formation time, experimental setups aiming at producing such shocks can be optimised to favourable conditions.
Quasi-bound states and continuum absorption background of polar Al0.5Ga0.5N/GaN quantum dots
Authors: Elmaghraoui D. , Triki M. , Jaziri S. , Leroux M. , Brault J.
Published: July 2014

A theoretical interpretation of the photoluminescence excitation spectra of self-organized polar GaN/(Al,Ga)N quantum dots is presented. A numerical method assuming a realistic shape of the dots and including the built-in electric field effects is developed to calculate their energy structure and hence their optical absorption. The electron and hole spectra show the existence of a set of quasi-bound states that does not originate from the wetting layer and plays a crucial role in the observed absorption spectrum of the GaN/(Al,Ga)N dots. Transitions involving these quasi-bound states and wetting layer states give a sufficient explanation for the observed continuum absorption background. The properties of this absorption band, especially its extension, depend strongly on the dot's size. Our simulation provides a natural explanation of the experimental luminescence excitation spectra of ensembles of dots of different heights. Our theoretical model can be convenient for future optical studies including systems with more complicated potentials.
Influence of composition and substrate miscut on the evolution of {105}-terminated in-plane Si1−xGex quantum wires on Si(001)
Authors: Watzinger H. , Glaser M. , Zhang J. J. , Daruka I. , Schäffler F.
Published: July 2014

Isolated in-plane wires on Si(001) are promising nanostructures for quantum transport applications. They can be fabricated in a catalyst-free process by thermal annealing of self-organized Si1−xGex hut clusters. Here, we report on the influence of composition and small substrate miscuts on the unilateral wire growth during annealing at 570 °C. The addition of up to 20% of Si mainly affects the growth kinetics in the presence of energetically favorable sinks for diffusing Ge atoms, but does not significantly change the wire base width. For the investigated substrate miscuts of <0.12°, we find geometry-induced wire tapering, but no strong influence on the wire lengths. Miscuts <0.02° lead to almost perfect quantum wires terminated by virtually step-free {105} and {001} facets over lengths of several 100 nm. Generally, the investigated Si1−xGex wires are metastable: Annealing at ≥600 °C under otherwise identical conditions leads to the well-known coexistence of Si1−xGex pyramids and domes.
Multi-channel composite spoof surface plasmon polaritons propagating along periodically corrugated metallic thin films
Authors: Liu Liangliang , Li Zhuo , Gu Changqing , Ning Pingping , Xu Bingzheng , Niu Zhenyi , Zhao Yongjiu
Published: July 2014

In this work, we demonstrate that composite spoof surface plasmon polaritons can be excited by coplanar waveguide, which are composed of two different spoof surface plasmon polaritons (SSPPs) modes propagating along a periodically corrugated metallic thin film simultaneously. These two SSPPs correspond to the dominant modes of one-dimensional (1D) periodical hole and groove arrays separately. We have designed and simulated a planar composite plasmonic waveguide in the microwave frequencies, and the simulation results show that the composite plasmonic waveguide can achieve multi-channel signal transmission with good propagation performance. The proposed planar composite plasmonic metamaterial can find potential applications in developing surface wave devices in integrated plasmonic circuits and multi-channel signal transmission systems in the microwave and terahertz frequencies.
Tunable surface anisotropy of synthetic antiferromagnetic free layer
Authors: Chang Jui-Hang , Chang Ching-Ray
Published: July 2014

We have studied the magnetostatic energies of three different kinds of ferromagnetic trilayer structures in which a nonmagnetic spacer inserts. It is shown that the surface roughness results in an additional effective perpendicular anisotropy. In the continuous and hybrid multilayer structures, the roughness-induced anisotropy is inversely proportional to the film thickness; however, the behavior disappears in discontinuous one. By considering the correlation between the surfaces, the effective perpendicular anisotropy can be further increased with increasing roughness and interlayer thickness.
Role of surface states and defects in the ultrafast nonlinear optical properties of CuS quantum dots
Authors: Mary K. A. Ann , Unnikrishnan N. V. , Philip Reji
Published: July 2014

We report facile preparation of water dispersible CuS quantum dots (2–4 nm) and nanoparticles (5–11 nm) through a nontoxic, green, one-pot synthesis method. Optical and microstructural studies indicate the presence of surface states and defects (dislocations, stacking faults, and twins) in the quantum dots. The smaller crystallite size and quantum dot formation have significant effects on the high energy excitonic and low energy plasmonic absorption bands. Effective two-photon absorption coefficients measured using 100 fs laser pulses employing open-aperture Z-scan in the plasmonic region of 800 nm reveal that CuS quantum dots are better ultrafast optical limiters compared to CuS nanoparticles.
Sheared and unsheared rotation of driven dust clusters
Authors: Schablinski Jan , Block Dietmar , Carstensen Jan , Greiner Franko , Piel Alexander
Published: July 2014

Finite size plasma crystals confined in an anisotropic potential well were studied under a rotating and radially unsheared drive in experiment and simulation at moderate rotational frequencies. A radially sheared rotation of these strongly coupled systems is observed for most cluster configurations with a low symmetry. The results show that a differential rotation can be effected by a non-sheared driving force.
Exciton localization and drift in tailored-potential quantum nanowires
Authors: Szeszko J. , Belykh V. V. , Rudra A. , Sibeldin N. N. , Kapon E.
Published: July 2014

Exciton recombination dynamics in tailored-potential, site-controlled AlGaAs quantum wires (QWRs) are studied. Time-resolved photoluminescence spectra evidence exciton localization in weakly disordered “uniform” QWRs, whereas deterministic bandgap grading is shown to suppress localization and promote exciton drift along the potential gradient. Measured exciton transit times between two quantum dot probes placed at opposite ends of the potential gradient yield the effective 1D exciton mobility as >1300 cm2/(eVs).
Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation
Authors: Tang Jia-Jun , Yang Xiao-Bao , Chen Li-Juan , Zhao Yu-Jun
Published: July 2014

We have theoretically investigated the modeling and the structural stabilities of various Mg/MgH2 interfaces, i.e. Mg($10\bar 10$101¯0)/MgH2(210), Mg(0001)/MgH2(101) and Mg($10\bar 10$101¯0)/MgH2(101), and provided illuminating insights into Mg/MgH2 interface. Specifically, the main factors, which impact the interfacial energies, are fully considered, including surface energies of two phases, mutual lattice constants of interface model, and relative position of two phases. The surface energies of Mg and MgH2, on the one hand, are found to be greatly impacting the interfacial energies, reflected by the lowest interfacial energy of Mg(0001)/MgH2(101) which is comprised of two lowest energy surfaces. On the other hand, it is demonstrated that the mutual lattice constants and the relative position of two phases lead to variations of interfacial energies, thus influencing the interface stabilities dramatically. Moreover, the Mg-H bonding at interface is found to be the determinant of Mg/MgH2 interface stability. Lastly, interfacial and strain effects on defect formations are also studied, both of which are highly facilitating the defect formations. Our results provide a detailed insight into Mg/MgH2 interface structures and the corresponding stabilities.
Direct observation of the topological charge of a terahertz vortex beam generated by a Tsurupica spiral phase plate
Authors: Miyamoto K. , Suizu K. , Akiba T. , Omatsu T.
Published: July 2014

A terahertz (THz) spiral phase plate with high transmission (>90% after Fresnel correction) and low dispersion has been developed based on the Tsurupica olefin polymer. Direct observations of the topological charge (both magnitude and sign) of a THz vortex beam are performed by using a THz camera with tilted lens focusing and radial defect introduction. The vortex outputs with a topological charge of ±1 (or ±2) are obtained at a frequency of 2 (or 4) THz.
Potential-well depth at amorphous-LaAlO3/crystalline-SrTiO3 interfaces measured by optical second harmonic generation
Authors: De Luca Gabriele , Rubano Andrea , Gennaro Emiliano di , Khare Amit , Granozio Fabio Miletto , di Uccio Umberto Scotti , Marrucci Lorenzo , Paparo Domenico
Published: July 2014

By a combination of optical second harmonic generation and transport measurements, we have investigated interfaces formed by either crystalline or amorphous thin films of LaAlO3 grown on TiO2-terminated SrTiO3(001) substrates. Our approach aims at disentangling the relative role of intrinsic and extrinsic doping mechanisms in the formation of the two-dimensional electron gas. The different nature of the two mechanisms is revealed when comparing the sample response variation as a function of temperature during annealing in air. However, before the thermal treatment, the two types of interfaces show almost the same intensity of the second harmonic signal, provided the overlayer thickness is the same. As we will show, the second harmonic signal is proportional to the depth of the potential well confining the charges at the interface. Therefore, our result demonstrates that this depth is about the same for the two different material systems. This conclusion supports the idea that the electronic properties of the two-dimensional electron gas are almost independent of the doping mechanism of the quantum well.
Upconversion emission in Er-doped and Er/Yb-codoped ferroelectric Na0.5Bi0.5TiO3 and its temperature sensing application
Authors: Du Peng , Luo Laihui , Li Weiping , Yue Qingying
Published: July 2014

Upconversion emissions of Er-doped and Er/Yb-codoped Na0.5Bi0.5TiO3 have been studied. Under 980 nm excitation, all samples exhibit strong green and red upconversion emissions, which can be seen by naked eyes. The Er/Yb-codoped Na0.5Bi0.5TiO3 ceramic has stronger upconversion emission intensity than Er-doped Na0.5Bi0.5TiO3 ceramic. Additionally, the optical temperature sensing properties based on upconversion emissions of Er/Yb-codoped Na0.5Bi0.5TiO3 ceramic were also investigated. The results demonstrate that the maximum sensitivity and temperature sensing resolution were 0.0031 K−1 and 0.3 K respectively, suggesting that the Er/Yb-codoped Na0.5Bi0.5TiO3 has potential application as optical temperature sensing materials.
Substitution behavior of x(Na0.5K0.5)NbO3-(1 − x)BaTiO3 ceramics for multilayer ceramic capacitors by a near edge x-ray absorption fine structure analysis
Authors: Ha Jooyeon , Ryu Jiseung , Lee Heesoo
Published: July 2014

The doping effect of (Na0.5K0.5)NbO3 (NKN) as alternatives for rare-earth elements on the electrical properties of BaTiO3 has been investigated, in terms of their substitution behavior. The dielectric constant of a specimen with x = 0.05 was about 79% higher than that of pure BaTiO3, and the temperature coefficient of capacitance was satisfied by the X7R specification. The specimen with x = 0.05 showed the lowest tetragonality among the four compositions and had a fine grain size of <2 μm. Although the addition of NKN decreased the specimen's tetragonality, the electrical properties were enhanced by the formation of defect dipoles and conduction electrons, which resulted from an acceptor and donor substitution behavior. Through O K-edge near edge x-ray absorption fine structure spectroscopy, the practical substitution behavior was defined by the change in Ti 3d orbital states. The energy separation of the Ti 3d orbitals was more apparent with the specimen of x = 0.05, which is related to the donor level from the donor substitution of Nb5+ ion for Ti-sites. Therefore, the simultaneous substitution of Na+/K+ and Nb5+ ions into BaTiO3 can improve dielectric properties, based on the charge-transfer process.
Localized states of a semi-infinite zigzag graphene sheet with impurity lines
Authors: Cunha A. M. C. , Ahmed Maher Z. , Cottam M. G. , Filho R. N. Costa
Published: July 2014

The localized states of a semi-infinite zigzag graphene sheet are studied using a tight-binding model that allows for the inclusion of either one or two lines of impurities. These impurity lines of atoms are placed in rows labeled as n (n = 1, 2, 3, …), where n = 1 is the free edge. The localized defect modes associated with these impurities are studied analytically and numerically within a tridiagonal matrix formalism. For one impurity line, the modes are analyzed according to the position of that line on the sheet, whereas the modes for two impurities are studied also according to their separation and their positions relative to the edge. When an impurity line is located at the edge (n = 1), it is found that the edge states are modified. When the impurities are positioned away from an edge (n > 1), additional localized modes are found to occur that may be relatively flat in their dispersion.
Influence of a Bi surfactant on Sb incorporation in InAsSb alloys
Authors: Anderson Evan M. , Lundquist Adam M. , Sarney Wendy L. , Svensson Stefan P. , Carrington Peter J. , Pearson Chris , Millunchick Joanna M.
Published: July 2014

The influence of using a Bi surfactant during the growth of InAsSb on the composition was examined, and it was found that increasing Bi flux on the surface during growth inhibits the incorporation of Sb. Analysis of the data via a kinetic model of anion incorporation shows that surface Bi acts as a catalyst for InAs formation, thus inhibiting Sb incorporation.
An active metallic nanomatryushka with two similar super-resonances
Authors: Wu D. J. , Cheng Y. , Wu X. W. , Liu X. J.
Published: July 2014

The optical properties of a simple metallic nanomatryushka (nanosphere-in-a-nanoshell) with gain have been investigated theoretically. The spaser (surface plasmon amplification by stimulated emission of radiation) phenomena can be observed at two critical wavelengths in the active metallic nanomatryushkas. With increasing the gain coefficient of the middle layer, a similar super surface plasmon (SP) resonance is first found at the ω−+|1 mode of the active nanoparticles and then breaks down. With further increasing the gain coefficient, another similar super-resonance occurs at the ω−−|1 mode. The near-field enhancements in the active nanomatryushkas also have been greatly amplified at the critical wavelengths for ω−+|1 and ω−−|1 modes. It is further found that the amplifications of SPs in the active Ag–SiO2–Au nanoshell are strongest in four kinds of nanoshells and hence the largest near fields. The giant near-field enhancement can greatly enhance the Raman excitation and emission.
Structural properties of relaxed thin film germanium layers grown by low temperature RF-PECVD epitaxy on Si and Ge (100) substrates
Authors: Cariou R. , Ruggeri R. , Tan X. , Mannino Giovanni , Nassar J. , Roca i Cabarrocas P.
Published: July 2014

We report on unusual low temperature (175 °C) heteroepitaxial growth of germanium thin films using a standard radio-frequency plasma process. Spectroscopic ellipsometry and transmission electron microscopy (TEM) reveal a perfect crystalline quality of epitaxial germanium layers on (100) c-Ge wafers. In addition direct germanium crystal growth is achieved on (100) c-Si, despite 4.2% lattice mismatch. Defects rising from Ge/Si interface are mostly located within the first tens of nanometers, and threading dislocation density (TDD) values as low as 106 cm−2 are obtained. Misfit stress is released fast: residual strain of −0.4% is calculated from Moiré pattern analysis. Moreover we demonstrate a striking feature of low temperature plasma epitaxy, namely the fact that crystalline quality improves with thickness without epitaxy breakdown, as shown by TEM and depth profiling of surface TDD.
The local structure and ferromagnetism in Fe-implanted SrTiO3 single crystals
Authors: Lobacheva O. , Chavarha M. , Yiu Y. M. , Sham T. K. , Goncharova L. V.
Published: July 2014

We report a connection between the local structure of low-level Fe impurities and vacancies as the cause of ferromagnetic behavior observed in strontium titanate single crystals (STO), which were implanted with Fe and Si ions at different doses then annealed in oxygen. The effects of Fe doping and post-implantation annealing of STO were studied by X-ray Absorption Near Edge Structure (XANES) spectroscopy and Superconducting Quantum Interference Device magnetometry. XANES spectra for Fe and Ti K- and L-edge reveal the changes in the local environment of Fe and Ti following the implantation and annealing steps. The annealing in oxygen atmosphere partially healed implantation damages and changed the oxidation state of the implanted iron from metallic Fe0 to Fe2+/Fe3+ oxide. The STO single crystals were weak ferromagnets prior to implantation. The maximum saturation moment was obtained after our highest implantation dose of 2 × 1016 Fe atom/cm2, which could be correlated with the metallic Fe0 phases in addition to the presence of O/Ti vacancies. After recrystallization annealing, the ferromagnetic response disappears. Iron oxide phases with Fe2+ and Fe3+ corresponding to this regime were identified and confirmed by calculations using Real Space Multiple Scattering program (FEFF9).
Lattice parameters and Raman-active phonon modes of (InxGa1–x)2O3 for x < 0.4
Authors: Kranert Christian , Lenzner Jörg , Jenderka Marcus , Lorenz Michael , von Wenckstern Holger , Schmidt-Grund Rüdiger , Grundmann Marius
Published: July 2014

We present X-ray diffraction and Raman spectroscopy investigations of (InxGa1–x)2O3 thin films and bulk-like ceramics in dependence of their composition. The thin films grown by pulsed laser deposition have a continuous lateral composition spread allowing the determination of phonon mode properties and lattice parameters with high sensitivity to the composition from a single 2-in. wafer. In the regime of low indium concentration, the phonon energies depend linearly on the composition and show a good agreement between both sample types. We determined the slopes of these dependencies for eight different Raman modes. While the lattice parameters of the ceramics follow Vegard's rule, deviations are observed for the thin films. Further, we found indications of the high-pressure phase InGaO3 II in the thin films above a critical indium concentration, its value depending on the type of substrate.
Helical filaments
Authors: Barbieri Nicholas , Hosseinimakarem Zahra , Lim Khan , Durand Magali , Baudelet Matthieu , Johnson Eric , Richardson Martin
Published: July 2014

The shaping of laser-induced filamenting plasma channels into helical structures by guiding the process with a non-diffracting beam is demonstrated. This was achieved using a Bessel beam superposition to control the phase of an ultrafast laser beam possessing intensities sufficient to induce Kerr effect driven non-linear self-focusing. Several experimental methods were used to characterize the resulting beams and confirm the observed structures are laser air filaments.
Ultrasonic effect on the bubble nucleation and heat transfer of oscillating nanofluid
Authors: Zhao Nannan , Fu Benwei , Ma H. B.
Published: July 2014

Ultrasonic sound effect on bubble nucleation, oscillating motion activated by bubble formation, and its heat transfer enhancement of nanofluid was experimentally investigated. Nanofluid consists of distilled water and dysprosium (III) oxide (Dy2O3) nanoparticles with an average size of 98 nm and a mass ratio of 0.5%. Visualization results demonstrate that when the nanoparticles are added in the fluid influenced by the ultrasonic sound, bubble nucleation can be significantly enhanced. The oscillating motion initiated by the bubble formation of nanofluid under the influence of ultrasonic sound can significantly enhance heat transfer of nanofluid in an interconnected capillary loop.
An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator
Authors: Anania M. P. , Brunetti E. , Wiggins S. M. , Grant D. W. , Welsh G. H. , Issac R. C. , Cipiccia S. , Shanks R. P. , Manahan G. G. , Aniculaesei C. , van der Geer S. B. , de Loos M. J. , Poole M. W. , Shepherd B. J. A. , Clarke J. A. , Gillespie W. A. , MacLeod A. M. , Jaroszynski D. A.
Published: July 2014

Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. The number of photons measured is up to 9 × 106 per shot for a 100 period undulator, with a mean peak brilliance of 1 × 1018 photons/s/mrad2/mm2/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130 MeV with the radiation pulse duration in the range of 50–100 fs.
Stabilizing a magnetic vortex/antivortex array in single crystalline Fe/Ag(001) microstructures
Authors: Li J. , Tan A. , Moon K. W. , Doran A. , Marcus M. A. , Young A. T. , Arenholz E. , Ma S. , Yang R. F. , Hwang C. , Qiu Z. Q.
Published: July 2014

While a magnetic antivortex state can be created in ring structures, much effort has been devoted to stabilizing a magnetic antivortex as the ground state in a single island. Among many proposals, less attention has been paid to the role of magnetocrystalline anisotropy because most magnetic microstructures are made of polycrystalline materials. By patterning epitaxial Fe/Ag(001) films along different in-plane directions, we show that the Fe magnetocrystalline anisotropy plays a very important role in stabilizing different types of vortex/antivortex states. In particular, we find that an Fe island in the shape of an elongated hexagon favors vortex array formation when the long edge is parallel to the Fe easy magnetization axis, and favors the vortex-antivortex array formation when the long edge is parallel to the Fe hard magnetization axis.
A snapshot of the limnology of eastern Australian water bodies spanning the tropics to Tasmania: the land-use, climate, limnology nexus
Authors: Chang Jie Christine , Woodward Craig , Shulmeister James
Published: July 2014

The present study investigates 45 natural and artificial water bodies extending across the whole of eastern Australia from the tropics to Tasmania. A broad variety of physio-chemical, land-use and climatic parameters were measured. Reservoirs and other artificial water bodies responded to stressors in their catchments in a similar fashion to natural lakes, but tended to be less nutrient rich, possibly because of shorter residence times and active management. Salinity and pH were strongly correlated in the dataset. Bedrock had a strong influence on pH in freshwater lakes, whereas all highly saline lakes were alkaline, irrespective of bedrock. High concentrations of anions in saline lakes precluded the existence of acid conditions by binding available hydrogen ions. Almost all lakes fell on salinity axes that indicated marine origin for their salts. An assessment of the total nitrogen to total phosphorus molar ratios from the lakes in the present dataset indicated that productivity in Australian lakes could be limited by both nitrogen and phosphorus. Future research using macro-nutrient enrichment experiments should be pursued to confirm this preliminary observation. There was a strong positive correlation between regional aridity and lake eutrophication. This is typical of semi-arid and seasonally arid environments and reflects the concentration of nutrients owing to evaporative flux in shallow basins with high residence times.
Does coastal topography constrain marine biogeography at an oceanographic interface?
Authors: Waters Jonathan M. , Condie Scott A. , Beheregaray Luciano B.
Published: July 2014

Our understanding of the physical factors driving fine-scale structuring of marine biodiversity remains incomplete. Recent studies have hypothesised that oceanography and coastal geometry interact to influence marine biogeographic structure on small spatial scales. The coastal waters of eastern Tasmania, located at the oceanographic interface between two major boundary current systems (the East Australia Current (EAC) and the Leeuwin Current (LC)) represent an informative system for assessing this hypothesis. Parallel biogeographic and oceanographic analyses, focusing on the relative abundance of two widespread, larval-dispersed Nerita gastropods, suggest that the relative influences of the EAC and LC at this interface are modulated by coastal topographical variation. Specifically, east-facing coastal sites are dominated by the EAC-derived N. melanotragus, whereas south-facing bays are dominated by LC-derived N. atramentosa. These combined oceanographic and biological data imply that coastal topography and hydrodynamics can combine to influence the local distributions and abundances of planktotrophic-developing taxa at coastal convergence zones.
Argumentation and informed consent in the doctor–patient relationship
Authors: Bickenbach Jerome
Published: July 2014

Argumentation theory has much to offer our understanding of the doctor–patient relationship as it plays out in the context of seeking and obtaining consent to treatment. In order to harness the power of argumentation theory in this regard, I argue, it is necessary to take into account insights from the legal and bioethical dimensions of informed consent, and in particular to account for features of the interaction that make it psychologically complex: that there is a fundamental asymmetry of authority, power and expertise between doctor and patient; that, given the potential for coercion, it is a challenge to preserve the interactive balance presumed by the requirement of informed consent; and finally that the necessary condition that patients be ‘competent to consent’ may undermine the requirement of respecting patient autonomy. I argue argumentation theory has the resources to deal with these challenges and expand our knowledge, and appreciation, of the informed consent interaction in health care.
Institutional constraints on strategic maneuvering in shared medical decision-making
Authors: Snoeck Henkemans Francisca , Mohammed Dima
Published: July 2014

In this chapter it is first investigated to what extent the institutional goal and basic principles of shared decision making are compatible with the aim and rules for critical discussion. Next, some techniques that doctors may use to present their own treatment preferences strategically in a shared decision making process are discussed and evaluated both from the perspective of the ideal of shared decision making and from that of critical discussion.
Direct-to-consumer advertisements for prescription drugs as an argumentative activity type
Authors: Wierda Renske , Visser Jacky
Published: July 2014

With direct-to-consumer advertisements (DTCA), pharmaceutical companies can market their prescription drugs directly to consumers. In order to properly study the argumentative aspects of these advertisements from a pragma-dialectical perspective, it is necessary to characterize DTCA as an ‘argumentative activity type’. This characterization shows that in DTCA, the advertiser combines two genres of communicative activity: promotion and consultation. The use of promotion stems from the advertiser’s commercial objective of selling products, while the use of consultation is a result of the legal obligation to present a fair balance between arguments for and against the use of a drug.
The strategic function of variants of pragmatic argumentation in health brochures
Authors: van Poppel Lotte
Published: July 2014

In this chapter, I examine the strategic function of four variants of pragmatic argumentation in the context of advisory health brochures. I argue that each variant functions as a strategic maneuver that deals with potential countermoves: with variant I and II writers can address anticipated doubt with respect to the standpoint and with variants III and IV they can strategically erase potential criticism of or possible alternatives to the proposed action.
“It is about our body, our own body!”
Authors: Schulz Peter J. , Meuffels Bert
Published: July 2014

This chapter is concerned with the reasons why sometimes good arguments in health communication leaflets fail to convince the targeted audience. As an illustrative example it uses the age-dependent eligibility of women in the Netherlands to receive routine breast cancer screening examinations: according to Dutch regulations women under 50 are ineligible for them. The present qualitative study rests on and complements three experimental studies on the persuasiveness of mammography information leaflets; it uses interviews to elucidate reasons why the arguments in the health communication leaflets for the exclusion of women under 50 from routine mammographic screenings do not work.
Plurilingualism and the challenges  of education
Authors: Coste Daniel
Published: July 2014

The purpose of this contribution is to retrace a movement of extension and integration from foreign language teaching to plurilingual education. Extension in so far as foreign language learning is more and more seen as one of the most important goals for school systems. Integration in so far as foreign language learning may be acknowledged today as a fundamental part of a more general plurilingual education serving several aims well beyond developing communicative competence in different languages. Within the Modern languages projects of the Council of Europe focus has shifted onto the place and function of languages in the whole curriculum and their key role in the educational process. This is largely due to a reinterpretation of the notion of plurilingual (and pluricultural) competence and to the inclusion of the language of schooling in the analyses and proposals regarding languages in/for education.
Australian Language Policy and the design of a national curriculum for languages
Authors: Möllering Martina
Published: July 2014

Australia’s efforts at valuing its multilingualism through the development of national language policy have been acclaimed by international scholars on bilingualism, but all is not well with Australia’s state as a multilingual society. A significant proportion of the population is bi- or multilingual, but this is not the norm, which is particularly obvious in the education sector where Australia-wide less than 15% of students in year 12, the final year of schooling, take a language other than English. In 2011, a national language curriculum Shape of the Australian Curriculum: Languages was drafted, which is discussed in this contribution against the background of Australian language policy and with a particular focus on the distinction between different pathways of language learning.
Effects of biliteracy on third language reading proficiency, the example of Turkish-German bilinguals
Authors: Rauch Dominique
Published: July 2014

The paper at hand compares the effects of bilingual language use and biliteracy on third language reading comprehension. Data of 280 9th-graders from 14 schools in Hamburg, Germany, were analyzed for the research. Using a questionnaire on language use at home, 142 students were identified as monolingual speakers of German and 138 students as bilingual speakers of Turkish and German. All students were tested in reading comprehension in German (GRC) and English (ERC), which is the third language of the bilinguals. Students with a background in Turkish were tested in Turkish reading comprehension (TRC), too. On the basis of the TRC and GRC test the bilingual students were grouped into fully biliterate students and partially biliterate. Controlling for a set of comprehensive cognitive and socio-economic variables, multivariate regression analysis revealed a negative association between the oral use of Turkish and German in daily life and English reading comprehension but a positive association of biliteracy in Turkish and German and English reading comprehension. In contrast to a bilingualism, which is related to spoken language only, biliteracy seems to be positively associated with third language acquisition.
Developing a written lexicon in a multilingual environment
Authors: Llaurado Anna , Tolchinsky Liliana
Published: July 2014

Children educated in Catalonia are growing in a multilingual environment. Catalan is their school language but not necessarily their home or social language. Our goal was to track the presence of such multilingual input in the written lexicon of 2,436 students throughout compulsory schooling. Participants were asked to write down as many names as they remembered of five semantic fields and to produce 6 types of text. The two corpora were tapped for the presence of non-Catalan and hybrid constructions. Unexpectedly, these accounted for only 3% of the total number of lexical forms in the corpora. The imperviousness of the corpora to multilingual influence is discussed in terms of the constraints placed by the written modality and by the school-situated conditions of task production.
The extrinsic plural marker in Korean
Authors: Kim Chae Eun , O’Grady William , Deen Kamil
Published: July 2014

This paper presents a series of experiments designed to shed light on some aspects of the use and interpretation of so-called ‘extrinsic -tul’ by child and adult native speakers of Korean. Our findings indicate that this morpheme occurs far less frequently than the intrinsic plural marker in both speech and writing, and that it is most likely to appear on an adverb. An experiment designed to confirm its oft-claimed status as a distributive marker reveals that whereas adults systematically interpret it in this way, children under the age of 8 rarely do, even when appropriate contextual support is provided.
The ambiguity and alternative construals of the [X-ko iss-ta] construction in Korean
Authors: Park Chongwon
Published: July 2014

This article analyzes the Korean [X-ko iss-ta] construction from the perspective of construal-based semantics, where the speaker’s choice and the grammatical context play an important role. The [X-ko iss-ta] construction exhibits ambiguity between the Progressive and the Resultant meanings. I argue that the Progressive reading is associated with the accomplishment construal of the construction, while the Resultant reading is associated with the achievement construal. I further argue that this type of alternative construal is motivated by the granularity observed ubiquitously in our everyday language. In terms of the function of -ko iss-, I argue that it segments out a smaller portion of the profiled semantic contour for focused viewing — an advantageous perspective from which to analyze stative verbs. My construal-based semantic analysis overcomes difficulties left by the previous proposals on the same topic.