bluuebunny/crossref_metadata_2025 huggingface dataset:
Vertically arrays of Si-LaNiO3/BiFeO3/Au core-shell nano-capacitors for prominent coupled electro-optic effect
Authors: Singh Kirandeep , Kaur Davinder
Published: March 2017

The current study delivers the first assessment of well-separated cone shaped n-type epitaxial BiFe0.9Mn0.1O3 (n-BFMO) shells integrated on LaNiO3 (LNO) buffered vertical arrays of p-type nanoporous Si nanowire cores as an absorber for high efficiency and sustainable all- oxide photovoltaic devices. The photovoltaic effect of the LNO/n-BFMO/Au radial heterojunction is investigated by registering the current-voltage curves under AM 1.5 (100 mW cm−2) illumination conditions at various ferroelectric polarization states of BFMO. The as-deposited LNO/BFMO/Au nanowire arrays fabricated by scalable Pulsed Laser deposition are completely self-polarized and produced a remarkably large open circuit photovoltage up to 0.53 V under zero poling condition. The direction of photocurrent and photovoltage is reversibly switchable in response to ferroelectric polarization switching. The short circuit photocurrent “ISC” and open circuit voltage “VOC” depict a hysteresis loop which is more or less identical to that of ferroelectric polarization and thus can be utilized as a nondestructive optical readout of the ferroelectric nonvolatile memories. By introducing special architecture for the BFO based photovoltaic device, a photoconversion efficiency ∼0.3% and External Quantum Efficiency ∼11% are achieved at zero polarization state, which can further be enhanced and modulated to ∼0.6% and 14%, respectively, at the negative poling state of BFMO.
Monolithic integration of individually addressable light-emitting diode color pixels
Authors: Chung Kunook , Sui Jingyang , Demory Brandon , Teng Chu-Hsiang , Ku Pei-Cheng
Published: March 2017

Monolithic integration of individually addressable light-emitting diode (LED) color pixels is reported. The integration is enabled by local strain engineering. The use of a nanostructured active region comprising one or more nanopillars allows color tuning across the visible spectrum. In the current work, integration of amber, green, and blue pixels is demonstrated. The nanopillar LEDs exhibit an electrical performance comparable to that of a conventional thin-film LED fabricated on the same wafer. The proposed platform uses only standard epitaxy and a similar process flow as a conventional LED. It is also shown that the emission intensity can be linearly tuned without shifting the color coordinate of individual pixels.
Absorption of the S-polarized short laser pulse in underdense plasma by considering the electrons ohmic heating and the laser pulse ponderomotive force effects
Authors: Panahi Naser , Ettehadi-Abari Mehdi , Hosseinnejad Mohammad-Taghi
Published: March 2017

With the advent of ultrashort high intensity laser pulses, laser absorption during laser-plasma interactions has received significant attention during the past two decades since it is related to a variety of applications of high intensity lasers, including the hot electron production for fast ignition of fusion targets, bright X-ray and gamma-ray sources, ion acceleration, compact neutron sources, and generally the creation of high energy density matters. Although some absorption mechanisms appear for short laser pulses with nanosecond duration time, they usually appear for some nonlinear phenomena as electron ohmic heating and laser pulse ponderomotive force are not considered. In this paper, the absorption of the S-polarized laser pulse through an interaction with an underdense plasma in attendance of electron ohmic heating and ponderomotive nonlinearities is analyzed. It is shown that, due to the effect of the ponderomotive force in both isothermal and non-isothermal plasmas, the increasing laser radiation angle leads to the increasing electric field wavelength. Also, since the ponderomotive force modifies the electron density and temperature distribution, it is shown that the decreasing radiation angle leads to the steepening of the electron density profile and the narrowing of electron bunching. Furthermore, by increasing the radiation angle, the absorption coefficient is decreased strongly. It is found that due to the heat of the plasma at the expanse of the wave energy in the case of a non-thermal plasma, the absorption coefficient is increased intensively in comparison to a collisional plasma.
Morphology of ion irradiation induced nano-porous structures in Ge and Si1−xGex alloys
Authors: Alkhaldi H. S. , Kremer F. , Mota-Santiago P. , Nadzri A. , Schauries D. , Kirby N. , Ridgway M. C. , Kluth P.
Published: March 2017

Crystalline Ge and Si1−xGex alloys (x = 0.83, 0.77) of (100) orientation were implanted with 140 keV Ge− ions at fluences between 5×1015 to 3×1017 ions/cm2, and at temperatures between 23 °C and 200 °C. The energy deposition of the ions leads to the formation of porous structures consisting of columnar pores separated by narrow sidewalls. Their sizes were characterized with transmission electron microscopy, scanning electron microscopy, and small angle x-ray scattering. We show that the pore radius does not depend significantly on the ion fluence above  5×1015 ions/cm2, i.e., when the pores have already developed, yet the pore depth increases from 31 to 516 nm with increasing fluence. The sidewall thickness increases slightly with increasing Si content, while both the pore radius and the sidewall thickness increase at elevated implantation temperatures.
Equation of state of Mo from shock compression experiments on preheated samples
Authors: Fat'yanov O. V. , Asimow P. D.
Published: March 2017

We present a reanalysis of reported Hugoniot data for Mo, including both experiments shocked from ambient temperature (T) and those preheated to 1673 K, using the most general methods of least-squares fitting to constrain the Grüneisen model. This updated Mie-Grüneisen equation of state (EOS) is used to construct a family of maximum likelihood Hugoniots of Mo from initial temperatures of 298 to 2350 K and a parameterization valid over this range. We adopted a single linear function at each initial temperature over the entire range of particle velocities considered. Total uncertainties of all the EOS parameters and correlation coefficients for these uncertainties are given. The improved predictive capabilities of our EOS for Mo are confirmed by (1) better agreement between calculated bulk sound speeds and published measurements along the principal Hugoniot, (2) good agreement between our Grüneisen data and three reported high-pressure γ(V) functions obtained from shock-compression of porous samples, and (3) very good agreement between our 1 bar Grüneisen values and γ(T) at ambient pressure recalculated from reported experimental data on the adiabatic bulk modulus Ks(T). Our analysis shows that an EOS constructed from shock compression data allows a much more accurate prediction of γ(T) values at 1 bar than those based on static compression measurements or first-principles calculations. Published calibrations of the Mie-Grüneisen EOS for Mo using static compression measurements only do not reproduce even low-pressure asymptotic values of γ(T) at 1 bar, where the most accurate experimental data are available.
Atomic clusters triggering nucleation and solidification of the metallic glass melt
Authors: Li Gong , Zhang Lijun , Zhan Zaiji , Yu Pengfei , Liaw Peter K. , Liu Riping
Published: March 2017

The Zr41Ti14Cu12.5Ni10Be22.5 (atomic percent, at. %) melts embedded in a flux of the dehydrated B2O3 were under cooled by the repeated treatment of melting. The maximum melt undercooling of ΔT = 145 K achieved for this melt corresponds to a comparatively large relative undercooling of 0.15 times the melting-point temperature of Tm∼ about 953 K(ΔT/Tm = 0.15). The solidification and nucleation behaviors of the Zr41Ti14Cu12.5Ni10Be22.5 undercooled melts triggered by Ni, Ti, Cu, and Zr clusters introduced by sputtering these pure metal targets are studied. An anomalous solidification triggered by Zr-atomic clusters above the Zr41Ti14Cu12.5Ni10Be22.5 melting temperature of 140 K is observed. The instability of a metallic-glass (MG) liquid near the thermodynamic critical temperature is present. The nucleation in the undercooled Zr41Ti14Cu12.5Ni10Be22.5 is investigated by Monte Carlo simulations and analyzed by the classical nucleation theory. This letter reveals an effective research method on investigating the instability of a MG liquid near the thermodynamic critical temperature.
Synthesis of second-order nonlinearities in dielectric-semiconductor-dielectric metamaterials
Authors: Lin Hung-Hsi , Yang Mu-Han , Sharma Rajat , Puckett Matthew W. , Montoya Sergio , Wurm Christian D. , Vallini Felipe , Fullerton Eric E. , Fainman Yeshaiahu
Published: March 2017

We demonstrate a large effective second-order nonlinear optical susceptibility in electronic optical metamaterials based on sputtered dielectric-semiconductor-dielectric multilayers of silicon dioxide/amorphous silicon (a-Si)/aluminum oxide. The interfacial fixed charges (Qf) with opposite signs on either side of dielectric-semiconductor interfaces result in a non-zero built-in electric field within the a-Si layer, which couples to the large third-order nonlinear susceptibility tensor of a-Si and induces an effective second-order nonlinear susceptibility tensor χeff(2). The value of the largest components of the effective χeff(2) tensor, i.e., χ(2)zzz, is determined experimentally to be 2 pm/V for the as-fabricated metamaterials and increases to 8.5 pm/V after the post-thermal annealing process. The constituents and fabrication methods make these metamaterials CMOS compatible, enabling efficient nonlinear devices for chip-scale silicon photonic integrated circuits.
Nanotwins soften boron-rich boron carbide (B13C2)
Authors: An Qi , Goddard William A.
Published: March 2017

Extensive studies of metals and alloys have observed that nanotwins lead to strengthening, but the role of nanotwins in ceramics is not well established. We compare here the shear strength and the deformation mechanism of nanotwinned boron-rich boron carbide (B13C2) with the perfect crystal under both pure shear and biaxial shear deformations. We find that the intrinsic shear strength of crystalline B13C2 is higher than that of crystalline boron carbide (B4C). But nanotwins in B13C2 lower the strength, making it softer than crystalline B4C. This reduction in strength of nanotwinned B13C2 arises from the interaction of the twin boundary with the C-B-C chains that connect the B12 icosahedra.
Characterization of Au/PbTi0.5Fe0.5O3/Si structure for possible multiferroic based non-volatile memory applications
Authors: Nawaz S. , Roy S. , Tulapurkar A. A. , Palkar V. R.
Published: March 2017

Magnetoelectric multiferroic PbTi0.5Fe0.5O3 films are deposited on a ⟨100⟩ conducting p-Si substrate without any buffer layer by using pulsed laser deposition and characterized for possible non-volatile memory applications. Their crystalline structure and surface morphology were characterized by using x-ray diffraction and AFM techniques. HRTEM was employed to determine the film–substrate interface. The electronic structure of the film was investigated by XPS, and no signature of metal was found for all the elements. The chemical shift of the Ti 2p XPS peak is attributed to the replacement of Ti with Fe in the PbTiO3 matrix. Piezoelectric force microscopy (PFM) results indicate the 180° phase shift of ferroelectric polarization. The upward self-polarization phenomenon is also observed in the PFM study. Magnetic and magneto-electric coupling measurements were carried out to confirm the magnetic nature and electro-magnetic coupling characteristics. C–V measurements exhibit clock-wise hysteresis loops with a maximum memory window of 1.2 V and a sweep voltage of ±7 V. This study could influence the fabrication of silicon compatible multiple memory device structures.
Refractive index and phase transformation of sapphire under shock pressures up to 210 GPa
Authors: Cao Xiuxia , Wang Yuan , Li Xuhai , Xu Liang , Liu Lixin , Yu Yin , Qin Rui , Zhu Wenjun , Tang Shihui , He Lin , Meng Chuanmin , Zhang Botao , Peng Xusheng
Published: March 2017

Under shock pressures up to 210 GPa, we measured the refractive index of sapphire at a wavelength of 1550 nm by performing plate impact experiments in order to investigate its refractive-index change behaviors and phase transitions along the Hugoniot state. There were two discontinuities in the refractive index at ∼65 to 92 GPa and ∼144 to 163 GPa, respectively. Moreover, above the Hugoniot elastic limit, the pressure dependence of the refractive index was divided into three segments, and there were large differences in their pressure-change trends: the refractive index decreased evidently with pressure in the first segment (∼20 to 65 GPa), remained nearly constant from ∼92 to ∼144 GPa in the second segment, and obviously increased with pressure in the last segment (∼163 to 210 GPa). Our first-principles calculations suggest that the observed discontinuities were closely related to the corundum-Rh2O3(II) and Rh2O3(II)-CaIrO3 structural transitions, and the shock-induced vacancy point defects could be one factor causing these great discrepancies in pressure-change trends. This work provides sapphire refractive-index information in a megabar-pressure range and clear evidence of its shock structural transitions. This not only has a great significance for the velocity correction of laser interferometer experiments and the analysis of sapphire high-pressure properties but also indicates a possible approach to explore the shock transitions of transparent materials.
Electrical resistivity anomaly, valence shift of Pr ion, and magnetic behavior in epitaxial (Pr1-yYy)1-xCaxCoO3 thin films under compressive strain
Authors: Fujishiro H. , Noda Y. , Akuzawa K. , Naito T. , Ito A. , Goto T. , Marysko M. , Jirak Z. , Hejtmanek J. , Nitta K.
Published: March 2017

We have fabricated (Pr1−yYy)1-xCaxCoO3 (PYCCO) epitaxial films with various thicknesses by pulsed laser deposition on the SrLaAlO4 (SLAO) substrate that applied an in-plane compressive stress to the film, and investigated the temperature dependence of the electrical resistivity, ρ(T), of the films. An anomalous ρ(T) upturn with a broad hysteresis could be clearly observed only for the thinnest film (d = 50 nm), and the ρ(T) anomaly decreased by increasing film thickness, d. The temperature dependence of the X-ray absorption near-edge structure (XANES) spectra at Pr L2-edge was measured for the films, and the valence states of praseodymium (Pr) ion were determined using the analysis of the XANES spectra. As a result, the average valence of the Pr ion in the d = 50 nm film slightly increases with decreasing temperature from the common value of 3.0+ around room temperature to 3.15+ at 8 K. The valence shift of Pr is thus similar to what was observed on the PYCCO polycrystalline bulks with an abrupt metal-insulator transition, accompanied by a spin-state (SS) transition of Co ions. Furthermore, the low-temperature SQUID measurements evidenced a paramagnetic behavior down to the lowest temperature, which suggests that the dominant part of Co3+ ions in the film grown on the SLAO substrate tends to be in the low spin state characteristic for the insulating ground state. These results strongly suggest that the anomalous ρ(T) upturn in the thin films on the SrLaAlO4 (SLAO) substrate is closely related to the SS transition of Co ions. On the other hand, PYCCO films grown on the LaAlO3 (LAO) substrate that applied an in-plane tensile stress showed no valence shift of Pr ions and developed a long range ferromagnetic order, which points to a complete suppression of the low-temperature transition. The behaviors of the epitaxial films are discussed in terms of the in-plane stress exerted by different substrates and accumulated elastic energy.
Magnetic and microstructural properties of sputter deposited Cr-doped aluminum nitride thin films on silicon substrates
Authors: Wistrela E. , Bittner A. , Schneider M. , Reissner M. , Schmid U.
Published: March 2017

In this paper, we report on the microstructural and magnetic properties of CrxAl1−xN thin films with Cr concentrations ranging up to x = (8.5 ± 0.5) at. %. The thin films are sputter deposited on silicon substrates and exhibit a wurtzite type microstructure verified by X-ray diffraction measurements. A vibrating sample magnetometer based measurement equipment is used to investigate magnetic properties of the Cr doped thin films in a temperature range of T = 10 K–300 K, revealing a paramagnetic behavior. With increasing temperature, the temperature independent diamagnetic contribution of the substrate material dominates the overall response characteristics. No room temperature ferromagnetism is observed for all samples investigated.
Importance of composite parameters in enhanced power conversion efficiency of Terfenol-D/PZT magnetoelectric gyrators
Authors: Leung Chung Ming , Zhuang Xin , Xu Junran , Li Jiefang , Srinivasan G. , Viehland D.
Published: March 2017

A gyrator that is capable of current-to-voltage conversion can be realized with a magnetoelectric (ME) composite of ferromagnetic and ferroelectric phases placed in a coil. Here, we report the dependence of the power conversion efficiency (PE) on the relative thickness of the two ferroic phases in a gyrator of Terfenol-D and PZT. Both experimental and theoretical results on PE as a function of composite parameters, such as thickness ratio of the ferroic layers (n), magnetic field bias (HBias) and several gyrator parameters, such as the resistance load (RL), were discussed. By decreasing the thickness ratio of Terfenol-D to composite (n = 0.28) in coil-ME gyrators, a high power efficiency of 73.9% was found at a fundamental resonance frequency of 72.5 kHz under a HBias of 1000 Oe and RL = 2.6 kΩ in experiments. At the same time, the non-linear mechanical loss was reduced by decreasing the value of n which resulted in a flat response over a wide HBias range. This improved power efficiency promises ME gyrators for power transfer devices.
Model of self assembled monolayer based molecular diodes made of ferrocenyl-alkanethiols
Authors: Duche David , Planchoke Ujwol , Dang Florian-Xuan , Le Rouzo Judikael , Bescond Marc , Simon Jean-Jacques , Balaban Teodor Silviu , Escoubas Ludovic
Published: March 2017

There has been significant work investigating the use of self assembled monolayers (SAMs) made of ferrocenyl terminated alkanethiols for realizing molecular diodes, leading to remarkably large forward-to-reverse current rectification ratios. In this study, we use a multiband barrier tunneling model to examine the electrical properties of SAM-based molecular diodes made of HSC9Fc, HSC11Fc, and HSCiFcC13−i (0 ≤ i ≤ 13). Using our simple physical model, we reproduce the experimental data of charge transport across various ferrocenyl substituted alkanethiols performed by Nijhuis, Reus, and Whitesides [J. Am. Chem. Soc. 132, 18386–184016 (2010)] and Yuan et al. [Nat. Commun. 6, 6324 (2015)]. Especially, the model allows predicting the rectification direction in HSCiFcC13−i (0 ≤ i ≤ 13) based molecular diodes depending on the position of the ferrocenyl (Fc) moiety within the molecules. We show that the asymmetry of the barrier length at both sides of the Highest Occupied Molecular Orbital of the ferrocenyl moiety strongly contributes to the rectifying properties of ferrocenyl-alkanethiol based molecular junctions. Furthermore, our results reveal that bound and quasi-bound states play an important role in the charge transport.
Stochastic simulation of reaction-diffusion systems: A fluctuating-hydrodynamics approach
Authors: Kim Changho , Nonaka Andy , Bell John B. , Garcia Alejandro L. , Donev Aleksandar
Published: March 2017

We develop numerical methods for stochastic reaction-diffusion systems based on approaches used for fluctuating hydrodynamics (FHD). For hydrodynamic systems, the FHD formulation is formally described by stochastic partial differential equations (SPDEs). In the reaction-diffusion systems we consider, our model becomes similar to the reaction-diffusion master equation (RDME) description when our SPDEs are spatially discretized and reactions are modeled as a source term having Poisson fluctuations. However, unlike the RDME, which becomes prohibitively expensive for an increasing number of molecules, our FHD-based description naturally extends from the regime where fluctuations are strong, i.e., each mesoscopic cell has few (reactive) molecules, to regimes with moderate or weak fluctuations, and ultimately to the deterministic limit. By treating diffusion implicitly, we avoid the severe restriction on time step size that limits all methods based on explicit treatments of diffusion and construct numerical methods that are more efficient than RDME methods, without compromising accuracy. Guided by an analysis of the accuracy of the distribution of steady-state fluctuations for the linearized reaction-diffusion model, we construct several two-stage (predictor-corrector) schemes, where diffusion is treated using a stochastic Crank–Nicolson method, and reactions are handled by the stochastic simulation algorithm of Gillespie or a weakly second-order tau leaping method. We find that an implicit midpoint tau leaping scheme attains second-order weak accuracy in the linearized setting and gives an accurate and stable structure factor for a time step size of an order of magnitude larger than the hopping time scale of diffusing molecules. We study the numerical accuracy of our methods for the Schlögl reaction-diffusion model both in and out of thermodynamic equilibrium. We demonstrate and quantify the importance of thermodynamic fluctuations to the formation of a two-dimensional Turing-like pattern and examine the effect of fluctuations on three-dimensional chemical front propagation. By comparing stochastic simulations to deterministic reaction-diffusion simulations, we show that fluctuations accelerate pattern formation in spatially homogeneous systems and lead to a qualitatively different disordered pattern behind a traveling wave.
Molecular dynamics simulation of ion flows around microparticles
Authors: Piel Alexander
Published: March 2017

The interaction of an ion flow with charged microparticles is studied by simulations with the molecular asymmetric dynamics (MAD) code. This code treats positive ions as “Yukawa particles” that are shielded by thermal electrons while the microparticle is assumed unshielded. The code is described and critically compared with results from published particle-in-cell simulations of other authors. As an application, the MAD code is used for a systematic study of the repulsive and ion-wake induced attractive forces in a particle pair. It is shown that the combined wake charges of a vertically, flow-aligned particle pair do not lead to a net attractive force. When the lower particle is shifted sidewards, a horizontal restoring force is found, which gives harmonic confinement for small displacements and a decreasing attraction force for a large distance.
The variation of large-scale structure inclination angles in high Reynolds number atmospheric surface layers
Authors: Liu Hong-You , Bo Tian-Li , Liang Yi-Rui
Published: March 2017

Field observations were performed to explore the variation of large-scale structure inclination angles in the high Reynolds number atmospheric surface layer (ASL). The high Reynolds number flow measurements [Reτ ∼ Ο (106)] were acquired at the Qingtu Lake observation array site. The structure inclination angles inferred from two-point correlations of the fluctuating streamwise velocity were obtained for different friction velocities in the neutral regime and different thermal stability conditions. Results indicate that, in addition to the Monin− Obukhov stability parameter, the structure inclination angle varies systematically with the friction velocity in the neutral surface layer. An empirical model is proposed to parametrize the variation of the inclination angle with the normalized friction velocity. The empirical formula agrees well with both the current ASL results and the previously documented results. Further analysis suggests that the inclination angle is dominated by the vertical velocity gradient (vertical wind shear) for both neutral and non-neutral regimes. The present work contributes to a better understanding of the inclination angle for the large-scale structures and may be used to improve the existing wall-models in the large-eddy simulation of the ASL.
A transmitting and receiving structure for high power applications
Authors: Guo Letian , Li Jiawei , Huang Wenhua , Shao Hao , Song Zhimin , Jiang Yue , Deng Guangjian
Published: March 2017

A high-power-capacity transmitting and receiving structure (TRS) is proposed. It has the ability of transmitting the GW-level high power microwave from the microwave sources with the horizontal polarized TE11 mode and receiving the microwave signal from the target with the orthogonal polarized TE11 mode. It is realized by the cooperation of a polarization-isolation-structure (PIS) and a two-way circular TE11 mode to rectangular TE10 mode power divider. Simulation shows that from 9.65 to 9.71 GHz, its power capacity is more than 3 GW at the transmitting format. The transmitting and receiving channel have an isolation of 60 dB which can prevent the receivers connecting to the receiving channel suffering from breakdown. The insertion losses for the transmitting and receiving format are both less than 0.03 dB.
Two solitons oblique collision in anisotropic non-extensive dusty plasma
Authors: El-Labany S. K. , El-Taibany W. F. , Behery E. E. , Fouda S. M.
Published: March 2017

Using an extended Poincaré-Lighthill-Kue method, the oblique collision of two dust acoustic solitons (DASs) in a magnetized non-extensive plasma with the effect of dust pressure anisotropy is studied. The dust fluid is supposed to have an arbitrary charge. A couple of Korteweg-de Vries (KdV) equations are derived for the colliding DASs. The phase shift of each soliton is obtained. It is found that the dust pressure anisotropy, the non-extensive parameter for electrons and ions, plays an important role in determining the collision phase shifts. The present results show that, for the negative dust case, the phase shift of the first soliton decreases, while that of the second soliton increases as either the dust pressure ratio increases or the ion non-extensive parameter decreases. On the other hand, for the positive dust case, the phase shift of the first soliton decreases, while the phase shift of the second soliton increases as either the dust pressure ratio or the ion non-extensive parameter increases. The application of the present findings to some dusty plasma phenomena occurring in space and laboratory plasmas is briefly discussed.
Comparative investigation of ELM control based on toroidal modelling of plasma response to RMP fields
Authors: Liu Yueqiang , Kirk A. , Li Li , In Y. , Nazikian R. , Sun Youwen , Suttrop W. , Lyons B. , Ryan D. , Wang Shuo , Yang Xu , Zhou Lina ,   EUROfusion MST1 team
Published: March 2017

Extensive modelling efforts of the plasma response to the resonant magnetic perturbation fields, utilized for controlling the edge localized mode (ELM), help to identify the edge-peeling response as a key factor, which correlates to the observed ELM mitigation in several tokamak devices, including MAST, ASDEX Upgrade, EAST, and HL-2A. The recently observed edge safety factor window for ELM mitigation in HL-2A experiments is explained in terms of the edge-peeling response. The computed plasma response, based on toroidal single fluid resistive plasma model with different assumption of toroidal flows, is found generally larger in ELM suppressed cases as compared to that of the ELM mitigated cases, in ASDEX Upgrade and DIII-D. The plasma shaping, in particular, the plasma triangularity, contributes to the enhanced plasma response. But the shaping does not appear to be the sole factor—other factors such as the (higher) pedestal pressure and/or current can also lead to increased edge-peeling response.
Pedestal radial flux measuring method to prevent impurity accumulation
Authors: Espinosa Silvia , Catto Peter J.
Published: March 2017

The use of high-z wall materials attempts to shift the fusion challenge from heat handling to impurity removal. We demonstrate that not only the impurity density in-out asymmetry but also the poloidal flow has a major impact on the radial impurity flux direction. This realization provides the first method of measuring the flux from available diagnostics, without the need of a computationally demanding kinetic calculation of the full bulk ion response. Moreover, it affords insight into optimal tokamak operation to avoid impurity accumulation while allowing free fueling.
Observation and modeling of interspecies ion separation in inertial confinement fusion implosions via imaging x-ray spectroscopy
Authors: Joshi T. R. , Hakel P. , Hsu S. C. , Vold E. L. , Schmitt M. J. , Hoffman N. M. , Rauenzahn R. M. , Kagan G. , Tang X.-Z. , Mancini R. C. , Kim Y. , Herrmann H. W.
Published: March 2017

We report the first direct experimental evidence of interspecies ion separation in direct-drive inertial confinement fusion experiments performed at the OMEGA laser facility via spectrally, temporally, and spatially resolved imaging x-ray-spectroscopy data [S. C. Hsu et al., Europhys. Lett. 115, 65001 (2016)]. These experiments were designed based on the expectation that interspecies ion thermo-diffusion would be the strongest for species with a large mass and charge difference. The targets were spherical plastic shells filled with D2 and a trace amount of Ar (0.1% or 1% by atom). Ar K-shell spectral features were observed primarily between the time of first-shock convergence and slightly before the neutron bang time, using a time- and space-integrated spectrometer, a streaked crystal spectrometer, and two gated multi-monochromatic x-ray imagers fielded along quasi-orthogonal lines of sight. Detailed spectroscopic analyses of spatially resolved Ar K-shell lines reveal the deviation from the initial 1% Ar gas fill and show both Ar-concentration enhancement and depletion at different times and radial positions of the implosion. The experimental results are interpreted using radiation-hydrodynamic simulations that include recently implemented, first-principles models of interspecies ion diffusion. The experimentally inferred Ar-atom fraction profiles agree reasonably with calculated profiles associated with the incoming and rebounding first shock.
Driving large magnetic Reynolds number flow in highly ionized, unmagnetized plasmas
Authors: Weisberg D. B. , Peterson E. , Milhone J. , Endrizzi D. , Cooper C. , Désangles V. , Khalzov I. , Siller R. , Forest C. B.
Published: March 2017

Electrically driven, unmagnetized plasma flows have been generated in the Madison plasma dynamo experiment with magnetic Reynolds numbers exceeding the predicted Rmcrit = 200 threshold for flow-driven MHD instability excitation. The plasma flow is driven using ten thermally emissive lanthanum hexaboride cathodes which generate a J×B torque in helium and argon plasmas. Detailed Mach probe measurements of plasma velocity for two flow topologies are presented: edge-localized drive using the multi-cusp boundary field and volumetric drive using an axial Helmholtz field. Radial velocity profiles show that the edge-driven flow is established via ion viscosity but is limited by a volumetric neutral drag force, and measurements of velocity shear compare favorably to the Braginskii transport theory. Volumetric flow drive is shown to produce larger velocity shear and has the correct flow profile for studying the magnetorotational instability.
Pulsed flying spot with the logarithmic parabolas method for the estimation of in-plane thermal diffusivity fields on heterogeneous and anisotropic materials
Authors: Gaverina L. , Batsale J. C. , Sommier A. , Pradere C.
Published: March 2017

A novel thermal non-destructive technique based on a Pulsed Flying Spot is presented here by considering in-plane logarithmic processing of the relaxing temperature field around the heat source spot. Recent progress made in optical control, lasers, and infrared cameras permits the acquisition of 2D temperature fields and localized thermal excitation on a small area instead of the entire recorded image. This study focuses on a new method based on spatial logarithm analysis of a temperature field to analyse and measure different parameters, such as the in-plane thermal diffusivity and localization of the spot. In this paper, this method is presented and the first results of heterogeneous anisotropic materials are depicted. The in-plane thermal diffusivity is estimated with an error lower than 4%, and the initial location of the heating spot is determined.
Investigation of a nitrogen post-discharge of an atmospheric-pressure microwave plasma torch by optical emission spectroscopy
Authors: Chen Chuan-Jie , Li Shou-Zhe
Published: March 2017

The species, N2(C), N2(B), and N2+(B), in the post-discharge of a nitrogen microwave induced discharge (2.45 GHz) at atmospheric pressure are investigated by means of optical emission diagnosis of the spatial distribution of emission intensities of N2(C-B), N2(B-A), and N2+(B-X) transitions. Correspondingly, the post-discharge can be divided into two distinct regimes, the early and late afterglows. It is found that not only atomic N survives in the late afterglow regime of the post-discharge but also the N2+ ions are produced even far from the microwave launcher. This is attributed to the fact that the vibrationally excited N2(X, υ) and ground state N(4S) with a long lifetime can be conveyed at far distance and act as the precursor for generating N2+ ions locally.
Droplet ejection and sliding on a flapping film
Authors: Chen Xi , Doughramaji Nicole , Betz Amy Rachel , Derby Melanie M.
Published: March 2017

Water recovery and subsequent reuse are required for human consumption as well as industrial, and agriculture applications. Moist air streams, such as cooling tower plumes and fog, represent opportunities for water harvesting. In this work, we investigate a flapping mechanism to increase droplet shedding on thin, hydrophobic films for two vibrational cases (e.g., ± 9 mm and 11 Hz; ± 2 mm and 100 Hz). Two main mechanisms removed water droplets from the flapping film: vibrational-induced coalescence/sliding and droplet ejection from the surface. Vibrations mobilized droplets on the flapping film, increasing the probability of coalescence with neighboring droplets leading to faster droplet growth. Droplet departure sizes of 1–2 mm were observed for flapping films, compared to 3–4 mm on stationary films, which solely relied on gravity for droplet removal. Additionally, flapping films exhibited lower percentage area coverage by water after a few seconds. The second removal mechanism, droplet ejection was analyzed with respect to surface wave formation and inertia. Smaller droplets (e.g., 1-mm diameter) were ejected at a higher frequency which is associated with a higher acceleration. Kinetic energy of the water was the largest contributor to energy required to flap the film, and low energy inputs (i.e., 3.3 W/m2) were possible. Additionally, self-flapping films could enable novel water collection and condensation with minimal energy input.
Examining the radiation drive asymmetries present in the high foot series of implosion experiments at the National Ignition Facility
Authors: Pak A. , Divol L. , Kritcher A. L. , Ma T. , Ralph J. E. , Bachmann B. , Benedetti L. R. , Casey D. T. , Celliers P. M. , Dewald E. L. , Döppner T. , Field J. E. , Fratanduono D. E. , Berzak Hopkins L. F. , Izumi N. , Khan S. F. , Landen O. L. , Kyrala G. A. , LePape S. , Millot M. , Milovich J. L. , Moore A. S. , Nagel S. R. , Park H.-S. , Rygg J. R. , Bradley D. K. , Callahan D. A. , Hinkel D. E. , Hsing W. W. , Hurricane O. A. , Meezan N. B. , Moody J. D. , Patel P. , Robey H. F. , Schneider M. B. , Town R. P. J. , Edwards M. J.
Published: March 2017

This paper details and examines the origins of radiation drive asymmetries present during the initial High Foot implosion experiments. Such asymmetries are expected to reduce the stagnation pressure and the resulting yield of these experiments by several times. Analysis of reemission and dual axis shock timing experiments indicates that a flux asymmetry, with a P2/P0 amplitude that varies from −10% to −5%, is present during the first shock of the implosion. This first shock asymmetry can be corrected through adjustments to the laser cone fraction. A thin shell model and more detailed radiation hydrodynamic calculations indicate that an additional negative P2/P0 asymmetry during the second or portions of the third shock is required to reach the observed amount of asymmetry in the shape of the ablator at peak implosion velocity. In conjunction with symmetry data from the x-ray self emission produced at stagnation, these models also indicate that after the initially negative P2/P0 flux asymmetry, the capsule experiences a positive P2/P0 flux asymmetry that develops at or before ∼2 ns into the peak of the laser power. Here, direct evidence for this inference, using measurements of the x-ray emission produced by the lasers irradiating the hohlraum, is presented. These data indicate that the reduction in the transmitted inner laser cone energy results from impeded propagation through the plasma associated with the ablation of the capsule target. This paper also correlates measurements of the outer cone laser deposition location with variations in the observed x-ray self emission shape from experiments conducted with nominally the same input conditions.
Cyclosis-mediated long distance communications of chloroplasts in giant cells of Characeae
Authors: Komarova Anna V. , Sukhov Vladimir S. , Bulychev Alexander A.
Published: March 2017

Long-distance communications in giant characean internodal cells involve cytoplasmic streaming as an effective means for transportation of regulatory substances. The local illumination of Chara corallina Klein ex C.L.Willdenow internodal cells with an intense 30 s pulse of white light caused a transient increase of modulated chlorophyll fluorescence in cell regions positioned downstream the cytoplasmic flow after a delay whose duration increased with the axial distance from the light source. No changes in fluorescence were observed in cell regions residing upstream of the light spot. The transient increase in actual fluorescence Fʹ in cell areas exposed to constant dim illumination at large distances from the brightly lit area indicates the transmission of photosynthetically active metabolite between chloroplasts separated by 1–5 mm distances. The shapes of fluorescence transients were sensitive to retardation of cytoplasmic streaming by cytochalasin D and to variations in cyclosis velocity during gradual recovery of streaming after an instant arrest of cyclosis by elicitation of the action potential. Furthermore, the analysed fluorescence transients were skewed on the ascending or descending fronts depending on the position of light-modulated cytoplasmic package at the moment of streaming cessation with respect to the point of measurements. The observations are simulated in qualitative terms with a simplified streaming–diffusion model.
Clans and clanlectal contact
Authors: Suokhrie Kelhouvinuo
Published: March 2017

This is the first variationist study of clan intermarriage and intergenerational change in Nagaland (India). The study investigates clan as a sociolinguistic variable by drawing data from the Angami (belonging to the Kuki-Chin-Naga sub-group of Tibeto-Burman languages) community of Kohima village in Nagaland. The linguistic variables examined include two alveolar fricatives and three affricates showing variable palatalization. Like many other clan-based communities (cf. Stanford, 2007, 2008, 2009), Angamis practice exogamy. Women settle down in their husband’s clans in the same village after marriage, but continue to maintain their original clanlects despite being in contact with their husband’s clanlects for many years. Exogamy practices are however weakening in Kohima, resulting in intra-clan marriages. The study examines the linguistic implications of the inter-clan and intra-clan marriages, illustrating the patterns that young learners acquire under such circumstances and the way they respond to the new changes. Labov finds evidence for an “outward orientation of the language learning faculty” (2012, 2014). The Nagaland results build on this notion but provide a new perspective: In Nagaland, children’s language learning is inwardly oriented with respect to stable variation and outwardly oriented in the case of change in progress.
Formalizing contemporary conceptual metaphor theory
Authors: Stickles Elise , David Oana , Dodge Ellen K. , Hong Jisup
Published: March 2017

This paper describes an innovative formalization of Conceptual Metaphor Theory and its implementation in a structured metaphor repository. Central to metaphor analysis is the development of an internal structure of frames and relations between frames, based on an Embodied Construction Grammar framework, which then informs the structure of metaphors and relationships between metaphors. The hierarchical nature of metaphors and frames is made explicit, such that inferential information originating in embodied conceptual primitives is inherited throughout the network. The present analysis takes a data-driven approach, where lexical differences in linguistic expressions attested in naturally-occurring discourse lead to a continued refinement and expansion of our analyses.
La femme, le chien et le clerc
Authors: Le Saux Françoise
Published: March 2017

Cette étude explore le réseau symbolique entre femme et animal dans le fabliau moyen-anglais Dame Sirith and the Weeping Bitch, et offre une réinterprétation du personnage de Margery à la lumière du Liber vaccae. Cet ouvrage (pseudo-)scientifique bien connu dans les milieux universitaires dès le début du XIIIe siècle atteste une croyance en la possibilité de transformer un être humain en animal: la crédulité de la jeune femme relèverait ainsi d’un trait de société, tout autant que d’une faiblesse personnelle. Les changements apportés par Caxton à sa version du fabliau – en particulier, sa substitution d’une chienne par une chatte dans son récit de la ruse de l’entremetteuse, et un retour au context païen de l’histoire telle que la relate Petrus Alfonsi – sont révélateurs d’un désir de distanciation par rapport à une thématique plus dérangeante que ne l’aurait soupçonné le lecteur du XXIe siècle.
Modes of transition and the timing of separatist war onset: a comparative analysis of South Ossetia and Kosovo
Authors: Dell'Aguzzo Loretta
Published: March 2017

This paper compares the escalation of civil war in South Ossetia and Kosovo and shows how different modes of transition deeply influenced the timing and type of conflict in these two cases. It argues that regimes resulting from a transition from above – when the elite in power leads the process of regime change and imposes its political agenda on other social actors – are more likely to ensure political stability in the short term, since governments are more cohesive internally, enjoy the support of the military, and can rely on a loyal bureaucracy. In contrast, regimes that emerge from transitions from below are more likely to experience civil war with an ethnic minority in the short term because of an intrinsic weakness of the elite in power. Under these circumstances, the newcomers need to win the loyalty of the military and of the bureaucracy, and separatist groups can take advantage of the incumbents’ weaknesses and try to build resources to militarily challenge the state.
Mozambican economic porosity and the role of Brazilian capital: a political economy analysis
Authors: Nogueira Isabela , Ollinaho Ossi , Pinto Eduardo Costa , Baruco Grasiela , Saludjian Alexis , Pinto José Paulo Guedes , Balanco Paulo , Schonerwald Carlos
Published: March 2017

After two decades of high growth and increased levels of foreign investment, Mozambique continues to face serious problems in reducing poverty. This article investigates the characteristics of Brazilian aid to and investment in Mozambique and scrutinises how these activities relate to the Mozambican growth. Combining the literature on the porosity of Mozambican growth with an analysis of the class dynamics of Brazilian accumulation, this article identifies the class fractions that sustained the Brazilian neo-developmental attempt and their capital internationalisation into Africa. Moreover, it empirically details their role in giving form to porosity in the Mozambique economy and promoting private gains at the expense of social losses.
Assessment of leg muscles mechanical capacities: Which jump, loading, and variable type provide the most reliable outcomes?
Authors: García‐Ramos Amador , Feriche Belén , Pérez‐Castilla Alejandro , Padial Paulino , Jaric Slobodan
Published: March 2017

This study aimed to explore the strength of the force–velocity (F–V) relationship of lower limb muscles and the reliability of its parameters (maximum force [F0], slope [a], maximum velocity [V0], and maximum power [P0]). Twenty‐three men were tested in two different jump types (squat and countermovement jump: SJ and CMJ), performed under two different loading conditions (free weight and Smith machine: Free and Smith) with 0, 17, 30, 45, 60, and 75 kg loads. The maximum and averaged values of F and V were obtained for the F–V relationship modelling. All F–V relationships were strong and linear independently whether observed from the averaged across the participants (r ≥ 0.98) or individual data (r = 0.94–0.98), while their parameters were generally highly reliable (F0 [CV: 4.85%, ICC: 0.87], V0 [CV: 6.10%, ICC: 0.82], a [CV: 10.5%, ICC: 0.81], and P0 [CV: 3.5%, ICC: 0.93]). Both the strength of the F–V relationships and the reliability of their parameters were significantly higher for (1) the CMJ over the SJ, (2) the Free over the Smith loading type, and (3) the maximum over the averaged F and V variables. In conclusion, although the F–V relationships obtained from all the jumps tested were linear and generally highly reliable, the less appropriate choice for testing the F–V relationship could be through the averaged F and V data obtained from the SJ performed either in a Free weight or in a Smith machine. Insubstantial differences exist among the other combinations tested.
Public Private partnerships in education and health in the global South:
a literature review
Authors: Languille Sonia
Published: March 2017

This paper presents the findings of a literature review on public
private partnerships (PPPs) in two sectors – education and health – in
Africa, Asia and Latin America. It highlights the heterogeneity of the
category within and across sectors and shows that the key predictions of the
PPP doctrine – cost-efficiency for improved social service delivery to the
poor – are hardly fulfilled in practice. Moreover, PPPs – both as policy
model and practical arrangements – are underpinned by a narrow conception of
education and health, which denies their broader embeddedness within the
economy and society. The paper identifies theoretical and methodological
limitations of the existing scholarship. It underlines the scarcity of data
on the corporate sector and, more broadly, about the economics of education
and health PPPs. It also stresses the little attention paid to the
beneficiaries. The paper finally calls for further research to open up the
‘black box’ of PPPs.
ELKS1 helps neuronal synapses diversify
Authors: Short Ben
Published: March 2017

Study reveals how neurons vary the properties of individual synapses by recruiting different Munc13 proteins to presynaptic active zones.