bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigation of edge-to-center density ratio in E-H mode transition of an inductively coupled plasma
Authors: Park Il-seo , Kang Hyun-Ju , Kim Kyung-Hyun , Chung Chin-Wook
Published: December 2017

The edge-to-center density ratio is investigated in an inductively coupled plasma which has two discharge modes depending on the rf power: the E- and H-mode. The power dependence of the edge-to-center density ratio is obtained from the ion flux at the wall and the electron flux at the center. The transitions of the density ratio of edge-to-center are observed during the E-H mode transition at various pressures, which has different trends depending on the pressure. These can be understood by the changes in the plasma characteristics due to the heating mode transition and electron kinetics by pressures. The theoretical edge-to-center density ratio is similar to the measured ratio at low pressures where the electrons are in non-local kinetics. However, at high pressures where the electrons are in local kinetics, the theoretical edge-to-center density ratio has a large discrepancy with the measured value in the E-mode due to local heating of electrons near the antenna. The density ratio of edge-to-center measured in the E-mode is larger than the theoretical ratio because the electron flux at the center is lower than that near the antenna. When the E-H mode transition occurs, the electron flux at the center is increased by the skin depth, which causes the decreased edge-to-center density ratio.
Orbital angular momentum of a π-pulse emission by dense relativistic cold electron beam
Authors: Arteaga J. A. , Serbeto A. , Mendonça J. T. , Tsui K. H. , Monteiro L. F.
Published: December 2017

Using a quantum fluid model, a set of three paraxial coupled equations to describe the free-electron laser instability is derived. These equations are solved numerically considering Laguerre-Gaussian modes as the initial conditions to study the transfer of orbital angular momentum between them, which satisfies the total angular momentum conservation as matching condition. The amplification and compression of the output radiation is observed. Using the method of separation of variables, the set of coupled equations, which describes a π-pulse solution, is obtained in such a way that a transverse overlapping factor, R, governs the energy exchange efficiency of the process.
Manipulation and simulations of thermal field profiles in laser heat-mode lithography
Authors: Wei Tao , Wei Jingsong , Wang Yang , Zhang Long
Published: December 2017

Laser heat-mode lithography is a very useful method for high-speed fabrication of large-area micro/nanostructures. To obtain nanoscale pattern structures, one needs to manipulate the thermal diffusion channels. This work reports the manipulation of the thermal diffusion in laser heat-mode lithography and provides methods to restrain the in-plane thermal diffusion and improve the out-of-plane thermal diffusion. The thermal field profiles in heat-mode resist thin films have been given. It is found that the size of the heat-spot can be decreased by decreasing the thickness of the heat-mode resist thin films, inserting the thermal conduction layers, and shortening the laser irradiation time. The optimized laser writing strategy is also given, where the in-plane thermal diffusion is completely restrained and the out-of-plane thermal diffusion is improved. The heat-spot size is almost equal to that of the laser spot, accordingly. This work provides a very important guide to laser heat-mode lithography.
A theoretical model for effect of electron radial diffusion on breakdown characteristics of DC Townsend discharge in uniform axial magnetic field
Authors: Noori H. , Rahmanipour R. , Ranjbar A. H.
Published: December 2017

The breakdown characteristics of gas discharge between two parallel disks including the electron losses in the discharge process due to radial diffusion have been discussed. A theoretical approach was established to determine the fraction of electrons lost from the discharge cell due to radial diffusion. Then, the dependency of the effective secondary electron emission coefficient on the inter-electrode spacing d, the electrode radius R, and the axial magnetic field B was studied. A particle-in-cell, Monte Carlo collision technique was employed to obtain the values of electron loss coefficient, δ, for d from 1 cm to 10 cm, R between 1 and 10 cm, B up to 300 G, and the gas pressures from 50 mTorr to 250 mTorr. The results show that the loss of the electrons increases exponentially with the distance d, while it decreases by increasing R. Based on the model, the applied magnetic field lowers the Paschen curve that is in agreement with the experimental data.
Electrical transport crossovers and thermopower in doped polyaniline conducting polymer
Authors: Brault D. , Lepinoy M. , Limelette P. , Schmaltz B. , Tran Van F.
Published: December 2017

We report on both the electrical and thermoelectric transport properties as a function of temperature in polyaniline doped with camphor sulfonic acid (CSA) for a wide range of CSA doping. A transport crossovers diagram illustrating metallic and insulating like behaviors is proposed and seems to result from the interplay between charge doping and disorder. In particular, the one half doping not only leads to an optimal electrical conductivity reaching 120 S/cm at 300 K but also the lowest thermopower slope. The measured thermopower appears closely related to the metallic onset in agreement with a metallic origin of its linear temperature dependence.
The magnetic transition temperature tuned by strain in YMn0.9Ru0.1O3 thin films
Authors: Yang L. P. , Zhang A. M. , Wang K. , Wu X. S. , Zhai Z. Y.
Published: December 2017

Epitaxial orthorhombic YMn0.9Ru0.1O3 films with different thickness have been grown on (001)-SrTiO3 substrates by pulsed laser deposition (PLD). The crystal structure is well investigated by X-ray Diffraction. It is found that the out-of-plane parameter c slowly increases with decreasing thickness of samples because of the tensile strain between the films and substrates along c axis. The lengths of in-plane Mn-O bonds expand with the enhancement of strains, which is proved by Raman scatting. The magnetic measurements reveal that there exist two magnetic transition temperatures TN1 and TN2. The TN1 is close to that of orthorhombic YMnO3 bulk. With decreasing thickness of the films, TN1 keeps almost constant because of the small stain along c-axis. TN2, however, obviously increases from 117 K to 134 K, which could be related to the expansion of in-plane Mn-O bonds. Results show that the magnetic transition temperature of YMn0.9Ru0.1O3 films can be sensitively manipulated by the strain of the films.
Shear-induced aggregation or disaggregation in edible oils: Models, computer simulation, and USAXS measurements
Authors: Townsend B. , Peyronel F. , Callaghan-Patrachar N. , Quinn B. , Marangoni A. G. , Pink D. A.
Published: December 2017

The effects of shear upon the aggregation of solid objects formed from solid triacylglycerols (TAGs) immersed in liquid TAG oils were modeled using Dissipative Particle Dynamics (DPD) and the predictions compared to experimental data using Ultra-Small Angle X-ray Scattering (USAXS). The solid components were represented by spheres interacting via attractive van der Waals forces and short range repulsive forces. A velocity was applied to the liquid particles nearest to the boundary, and Lees-Edwards boundary conditions were used to transmit this motion to non-boundary layers via dissipative interactions. The shear was created through the dissipative forces acting between liquid particles. Translational diffusion was simulated, and the Stokes-Einstein equation was used to relate DPD length and time scales to SI units for comparison with USAXS results. The SI values depended on how large the spherical particles were (250 nm vs. 25 nm). Aggregation was studied by (a) computing the Structure Function and (b) quantifying the number of pairs of solid spheres formed. Solid aggregation was found to be enhanced by low shear rates. As the shear rate was increased, a transition shear region was manifested in which aggregation was inhibited and shear banding was observed. Aggregation was inhibited, and eventually eliminated, by further increases in the shear rate. The magnitude of the transition region shear, γ̇t, depended on the size of the solid particles, which was confirmed experimentally.
First-order martensitic transformation in Heusler-type glass-coated microwires
Authors: Zhukov A. , Ipatov M. , del Val J. J. , Taskaev S. , Churyukanova M. , Zhukova V.
Published: December 2017

Properly annealed Ni-Mn-Ga glass-covered microwires exhibit a hysteretic anomaly on the temperature dependence of magnetization attributed to the first order martensitic transformation. The temperatures of the structural and magnetic transitions are drastically affected by annealing conditions. Annealed glass-coated Ni-Mn-Ga microwires show a Curie temperature shift close to room temperature. The temperature and magnetic field dependences of magnetization are discussed in terms of atomic disorder, the release of internal stresses, and recrystallization after annealing.
Test-electron analysis of the magnetic reconnection topology
Authors: Borgogno D. , Perona A. , Grasso D.
Published: December 2017

Three-dimensional (3D) investigations of the magnetic reconnection field topology in space and laboratory plasmas have identified the abidance of magnetic coherent structures in the stochastic region, which develop during the nonlinear stage of the reconnection process. Further analytical and numerical analyses highlighted the efficacy of some of these structures in limiting the magnetic transport. The question then arises as to what is the possible role played by these patterns in the dynamics of the plasma particles populating the chaotic region. In order to explore this aspect, we provide a detailed description of the nonlinear 3D magnetic field topology in a collisionless magnetic reconnection event with a strong guide field. In parallel, we study the evolution of a population of test electrons in the guiding-center approximation all along the reconnection process. In particular, we focus on the nonlinear spatial redistribution of the initially thermal electrons and show how the electron dynamics in the stochastic region depends on the sign and on the value of their velocities. While the particles with the highest positive speed populate the coherent current structures that survive in the chaotic sea, the presence of the manifolds calculated in the stochastic region defines the confinement area for the electrons with the largest negative velocity. These results stress the link between the magnetic topology and the electron motion and contribute to the overall picture of a non-stationary fluid magnetic reconnection description in a geometry proper to physical systems where the effects of the curvature can be neglected.
Empirical expression for DC magnetization curve of immobilized magnetic nanoparticles for use in biomedical applications
Authors: Elrefai Ahmed L. , Sasayama Teruyoshi , Yoshida Takashi , Enpuku Keiji
Published: December 2017

We studied the magnetization (M-H) curve of immobilized magnetic nanoparticles (MNPs) used for biomedical applications. First, we performed numerical simulation on the DC M-H curve over a wide range of MNPs parameters. Based on the simulation results, we obtained an empirical expression for DC M-H curve. The empirical expression was compared with the measured M-H curves of various MNP samples, and quantitative agreements were obtained between them. We can also estimate the basic parameters of MNP from the comparison. Therefore, the empirical expression is useful for analyzing the M-H curve of immobilized MNPs for specific biomedical applications.
Path-integral isomorphic Hamiltonian for including nuclear quantum effects in non-adiabatic dynamics
Authors: Tao Xuecheng , Shushkov Philip , Miller Thomas F.
Published: December 2017

We describe a path-integral approach for including nuclear quantum effects in non-adiabatic chemical dynamics simulations. For a general physical system with multiple electronic energy levels, a corresponding isomorphic Hamiltonian is introduced such that Boltzmann sampling of the isomorphic Hamiltonian with classical nuclear degrees of freedom yields the exact quantum Boltzmann distribution for the original physical system. In the limit of a single electronic energy level, the isomorphic Hamiltonian reduces to the familiar cases of either ring polymer molecular dynamics (RPMD) or centroid molecular dynamics Hamiltonians, depending on the implementation. An advantage of the isomorphic Hamiltonian is that it can easily be combined with existing mixed quantum-classical dynamics methods, such as surface hopping or Ehrenfest dynamics, to enable the simulation of electronically non-adiabatic processes with nuclear quantum effects. We present numerical applications of the isomorphic Hamiltonian to model two- and three-level systems, with encouraging results that include improvement upon a previously reported combination of RPMD with surface hopping in the deep-tunneling regime.
Spectroscopy of N,N-dimethylformamide in the VUV and IR regions: Experimental and computational studies
Authors: Shastri Aparna , Das Asim Kumar , Krishnakumar Sunanda , Singh Param Jeet , Raja Sekhar B. N.
Published: December 2017

The electronic absorption spectrum of N,N-dimethylformamide (DMF) is studied in the 45 000–80 000 cm−1 (5.6–9.9 eV) region using synchrotron radiation. The vacuum ultraviolet (VUV) spectrum comprises mostly of Rydberg series of ns, np, and nd types converging to the first two ionization potentials (IPs). Quantum defect values obtained are consistent with excitation of an electron from the highest occupied molecular orbitals localized on nitrogen (4a″) and oxygen (16a′); in addition, the 3s Rydberg transition converging to the third IP (3a″) is observed at 8.95 eV. A reinvestigation of the infrared spectrum of DMF in the 500–4000 cm−1 region with the help of density functional theory (DFT) calculations establishes the planarity of the ground state and leads to revision of several vibrational assignments. Vertical excited state energies and their valence/Rydberg character are predicted using time dependent DFT calculations; excellent correlation is achieved between theoretical results and experimentally observed spectral features. Potential energy curves of the first few excited states give additional insights into the nature of the excited states and their role in photodissociation dynamics. The absorption spectrum of DMF in the region >63 400 cm−1 (7.85 eV) as well as a complete set of spectral assignments in the VUV region (45 000–80 000 cm−1) is reported for the first time. This work represents a comprehensive study of the absorption spectra of DMF in the VUV and infrared regions.
Oxygen vacancies mediated ferromagnetism in hydrogenated Zn0.9Co0.1O film
Authors: Zhang Huiyun , Wang Ji , Cao Yanqiang , Guo Xinli , Li Qi , Du Jun , Xu Qingyu
Published: December 2017

Zn0.9Co0.1O films were prepared by pulsed laser deposition and followed by annealing treatment in hydrogen atmosphere. Both samples show ferromagnetic behavior and saturated ferromagnetic magnetization was significantly increased by five times after the hydrogenation treatment. Co ions in both samples have been confirmed to be bivalent as substituents. Moreover, hydrogenation did not change the ZnO wurtzite structure and no segregation of Co, Co oxides or any other secondary phases were detected. Furthermore, the Co 2p3/2 peaks shift to lower energy level after hydrogenation, excluding the formation of Co-H-Co complexes. The structural characterizations clearly confirmed that the increment of oxygen vacancies was due to the hydrogenation treatment. These results indicate that the oxygen vacancies play a crucial role in mediating the ferromagnetism in Zn0.9Co0.1O film.
Analysis of X-ray adsorption edges: L2,3 edge of FeCl4−
Authors: Bagus Paul S. , Nelin Connie J. , Ilton Eugene S. , Sassi Michel J. , Rosso Kevin M.
Published: December 2017

We describe a detailed analysis of the features of the X-ray adsorption spectra at the Fe L2,3 edge of FeCl4−. The objective of this analysis is to explain the origin of the complex features in relation to properties of the wavefunctions, especially for the excited states. These properties include spin-orbit and ligand field splittings where a novel aspect of the dipole selection rules is applied to understand the influence of these splittings on the spectra. We also explicitly take account of the intermediate coupling of the open core and valence shell electrons. Our analysis also includes comparison of theory and experiment for the Fe L2,3 edge and comparison of theoretical predictions for the Fe3+ cation and FeCl4−. The electronic structure is obtained from theoretical wavefunctions for the ground and excited states.
Accelerated path-integral simulations using ring-polymer interpolation
Authors: Buxton Samuel J. , Habershon Scott
Published: December 2017

Imaginary-time path-integral (PI) molecular simulations can be used to calculate exact quantum statistical mechanical properties for complex systems containing many interacting atoms and molecules. The limiting computational factor in a PI simulation is typically the evaluation of the potential energy surface (PES) and forces at each ring-polymer “bead”; for an n-bead ring-polymer, a PI simulation is typically n times greater than the corresponding classical simulation. To address the increased computational effort of PI simulations, several approaches have been developed recently, most notably based on the idea of ring-polymer contraction which exploits either the separation of the PES into short-range and long-range contributions or the availability of a computationally inexpensive PES which can be incorporated to effectively smooth the ring-polymer PES; neither approach is satisfactory in applications to systems modeled by PESs given by on-the-fly ab initio calculations. In this article, we describe a new method, ring-polymer interpolation (RPI), which can be used to accelerate PI simulations without any prior assumptions about the PES. In simulations of liquid water modeled by an empirical PES (or force field) under ambient conditions, where quantum effects are known to play a subtle role in influencing experimental observables such as radial distribution functions, we find that RPI can accurately reproduce the results of fully-converged PI simulations, albeit with far fewer PES evaluations. This approach therefore opens the possibility of large-scale PI simulations using ab initio PESs evaluated on-the-fly without the drawbacks of current methods.
Coercivity enhancement of Nd-Fe-B hot-deformed magnets by the eutectic grain boundary diffusion process using Nd-Ga-Cu and Nd-Fe-Ga-Cu alloys
Authors: Liu Lihua , Sepehri-Amin H. , Sasaki T. T. , Ohkubo T. , Yano M. , Sakuma N. , Kato A. , Shoji T. , Hono K.
Published: December 2017

Nd80Ga15Cu5 and Nd62Fe14Ga20Cu4 alloys were used as diffusion sources for the eutectic grain boundary diffusion process, applying to 4 mm-thick Nd-Fe-B hot-deformed magnets. Both samples showed nearly same coercivity of 2.2 T, while the sample processed with Nd62Fe14Ga20Cu4 showed smaller remanence deterioration from 1.50 T to 1.30 T, in contrast to that of the sample processed with Nd80Ga15Cu5 to 1.08 T. Mr/Ms of the initial sample and the samples processed with Nd62Fe14Ga20Cu4 and Nd80Ga15Cu5 were 0.946, 0.934 and 0.917, respectively, suggesting that the sample processed with Nd62Fe14Ga20Cu4 retains stronger c-axis texture after the diffusion process. Nd-rich phases with Ia3¯ and fcc structures were observed in the sample processed with Nd80Ga15Cu5, while the Nd-rich phases with the Ia3¯ and hcp structures were found in the sample processed with Nd62Fe14Ga20Cu4, all of which are the phases commonly observed in Nd-Fe-B sintered magnets.
Comparison between spin-orbit torques measured by domain-wall motions and harmonic measurements
Authors: Kim Joo-Sung , Nam Yune-Seok , Kim Dae-Yun , Park Yong-Keun , Park Min-Ho , Choe Sug-Bong
Published: December 2017

Here we report the comparison of the spin torque efficiencies measured by three different experimental schemes for Pt/Co/X stacks with material X (= Pt, Ta, Ti, Al, Au, Pd, and Ru. 7 materials). The first two spin torque efficiencies εDW(1) and εDW(2) are quantified by the measurement of spin-torque-induced effective field for domain-wall depinning and creeping motions, respectively. The last one—longitudinal spin torque efficiency εL—is measured by harmonic signal measurement of the magnetization rotation with uniform magnetization configuration. The results confirm that, for all measured Pt/Co/X stacks, εDW(1) and εDW(2) are exactly consistent to each other and these two efficiencies are roughly proportional to εL with proportionality constant π/2, which comes from the integration over the domain-wall configuration.
Construction of diabatic energy surfaces for LiFH with artificial neural networks
Authors: Guan Yafu , Fu Bina , Zhang Dong H.
Published: December 2017

A new set of diabatic potential energy surfaces (PESs) for LiFH is constructed with artificial neural networks (NNs). The adiabatic PESs of the ground state and the first excited state are directly fitted with NNs. Meanwhile, the adiabatic-to-diabatic transformation (ADT) angles (mixing angles) are obtained by simultaneously fitting energy difference and interstate coupling gradients. No prior assumptions of the functional form of ADT angles are used before fitting, and the ab initio data including energy difference and interstate coupling gradients are well reproduced. Converged dynamical results show remarkable differences between adiabatic and diabatic PESs, which suggests the significance of non-adiabatic processes.
Spin Hall driven domain wall motion in magnetic bilayers coupled by a magnetic oxide interlayer
Authors: Liu Yang , Furuta Masaki , Zhu Jian-Gang (Jimmy)
Published: December 2017

mCell, previously proposed by our group, is a four-terminal magnetoresistive device with isolated write- and read-paths for all-spin logic and memory applications. A mCell requires an electric-insulating magnetic layer to couple the spin Hall driven write-path to the magnetic free layer of the read-path. Both paths are magnetic layers with perpendicular anisotropy and their perpendicularly oriented magnetization needs to be maintained with this insertion layer. We have developed a magnetic oxide (FeOx) insertion layer to serve for these purposes. We show that the FeOx insertion layer provides sufficient magnetic coupling between adjacent perpendicular magnetic layers. Resistance measurement shows that this magnetic oxide layer can act as an electric-insulating layer. In addition, spin Hall driven domain wall motion in magnetic bi-layers coupled by the FeOx insertion layer is significantly enhanced compared to that in magnetic single layer; it also requires low voltage threshold that poses possibility for power-efficient device applications.
Intrinsic stress response of low and high mobility solute additions to Cu thin films
Authors: Kaub Tyler , Anthony Ryan , Thompson Gregory B.
Published: December 2017

Thin film stress is frequently controlled through adjustments applied to the processing parameters used during film deposition. In this work, we explore how the use of solutes with different intrinsic growth properties influences the residual growth stress development for a common solvent Cu film. The findings demonstrated that the addition of a high atomic mobility solute, Ag, or a low atomic mobility solute, V, results in both alloy films undergoing grain refinement that scaled with increases in the solute content. This grain refinement was associated with solute segregation and was more pronounced in the Cu(Ag) system. The grain size reduction was also associated with an increase in the tensile stresses observed in both alloy sets. These findings indicate that solutes can be used to control the grain size under the same deposition conditions, as well as alter the stress evolution of a growing thin film.
Mechanics modelling of fern cavitation catapult
Authors: Kang Jingtian , Li Kai , Tan Huifeng , Wang Changguo , Cai Shengqiang
Published: December 2017

Cavitation is often regarded as a failure mode in soft materials. An intriguing phenomenon has been recently discovered that fern sporangium can take advantage of drying-induced cavitation instability in annulus cells to disperse spores at an extraordinarily high acceleration. Briefly, the decrease of environmental humidity causes continuous bending of the sporangium and growth of cavities inside the annulus cells, with the elastic energy accumulated in sporangium walls. When the humidity is lower than a critical value, the cavities suddenly expand dramatically inside the cells, causing a quick release of the elastic energy stored in the annular structure. As a result, like a catapult, the sporangium snaps back and ejects the seeds at a high speed. Motivated by the observation, in this article, we study cavitation instability in a similar structure as the sporangium. To simplify the problem, in our model, the mechanics of cells in the sporangium are described by the polymer gel model, while the sporangium wall is modelled as a hyperelastic material. When the environmental humidity is lower than a critical value, through energetic analyses, we can predict the cavitation catapult phenomenon using the model. We hope that our study in this article can provide useful insights into the bio-inspired design of structures which can take advantage of cavitation instability in soft materials.
Partial ablation of Ti/Al nano-layer thin film by single femtosecond laser pulse
Authors: Gaković B. , Tsibidis G. D. , Skoulas E. , Petrović S. M. , Vasić B. , Stratakis E.
Published: December 2017

The interaction of ultra-short laser pulses with Titanium/Aluminium (Ti/Al) nano-layered thin film was investigated. The sample composed of alternating Ti and Al layers of a few nanometres thick was deposited by ion-sputtering. A single pulse irradiation experiment was conducted in an ambient air environment using focused and linearly polarized femtosecond laser pulses for the investigation of the ablation effects. The laser induced morphological changes and the composition were characterized using several microscopy techniques and energy dispersive X-ray spectroscopy. The following results were obtained: (i) at low values of pulse energy/fluence, ablation of the upper Ti layer only was observed; (ii) at higher laser fluence, a two-step ablation of Ti and Al layers takes place, followed by partial removal of the nano-layered film. The experimental observations were supported by a theoretical model accounting for the thermal response of the multiple layered structure upon irradiation with ultra-short laser pulses.
Single-user MIMO system, Painlevé transcendents, and double scaling
Authors: Chen Hongmei , Chen Min , Blower Gordon , Chen Yang
Published: December 2017

In this paper, we study a particular Painlevé V (denoted PV) that arises from multi-input-multi-output wireless communication systems. Such PV appears through its intimate relation with the Hankel determinant that describes the moment generating function (MGF) of the Shannon capacity. This originates through the multiplication of the Laguerre weight or the gamma density xαe−x, x > 0, for α > −1 by (1 + x/t)λ with t > 0 a scaling parameter. Here the λ parameter “generates” the Shannon capacity; see Chen, Y. and McKay, M. R. [IEEE Trans. Inf. Theory 58, 4594–4634 (2012)]. It was found that the MGF has an integral representation as a functional of y(t) and y′(t), where y(t) satisfies the “classical form” of PV. In this paper, we consider the situation where n, the number of transmit antennas, (or the size of the random matrix), tends to infinity and the signal-to-noise ratio, P, tends to infinity such that s = 4n2/P is finite. Under such double scaling, the MGF, effectively an infinite determinant, has an integral representation in terms of a “lesser” PIII. We also consider the situations where α=k+1/2,k∈N, and α ∈ {0, 1, 2, …}, λ ∈ {1, 2, …}, linking the relevant quantity to a solution of the two-dimensional sine-Gordon equation in radial coordinates and a certain discrete Painlevé-II. From the large n asymptotic of the orthogonal polynomials, which appears naturally, we obtain the double scaled MGF for small and large s, together with the constant term in the large s expansion. With the aid of these, we derive a number of cumulants and find that the capacity distribution function is non-Gaussian.
Dynamic stabilization of filamentation instability
Authors: Kawata S. , Gu Y. J. , Li X. F. , Karino T. , Katoh H. , Limpouch J. , Klimo O. , Margarone D. , Yu Q. , Kong Q. , Weber S. , Bulanov S. , Andreev A.
Published: December 2017

The paper presents a study on dynamic stabilization of filamentation instability driven by an electron beam introduced into a plasma. The results presented in the paper demonstrate that the filamentation instability is successfully stabilized by the dynamic stabilization mechanism, in which the electron beam axis oscillates. The dynamic stabilization mechanism for plasma instability was proposed in the paper [Kawata, Phys. Plasmas 19, 024503 (2012)]. In general, instabilities emerge from the perturbations of the physical quantity. Normally the perturbation phase is unknown so that the instability growth rate is discussed. However, if the perturbation phase is known, the instability growth can be controlled by a superimposition of perturbations imposed actively: if the perturbation is introduced by, for example, a driving beam axis oscillation or so, the perturbation phase can be controlled and the instability growth is mitigated by the superimposition of the growing perturbations.
Influence of the social determinants of health on access to healthcare services among refugees in Australia
Authors: Taylor Jessica , Lamaro Haintz Greer
Published: December 2017

Refugees in Australia are not fully utilising the healthcare system for several reasons and this may be affecting their overall health outcomes. This qualitative systematic review examined the influence of the social determinants of health on refugees’ access to healthcare services in Australia. Electronic databases were searched using terms relating to refugees, social determinants, healthcare services, barriers, enablers and Australia. Only peer-reviewed studies published in English since 2006, which focused on refugees and specifically discussed social determinants influencing refugees’ access to healthcare services in Australia, were included. The studies were critically analysed using standard Critical Appraisal Skills Programme Tools. Eight studies were included in the review. Findings reveal multiple factors influence refugees’ access to healthcare in Australia, and these can be conceptualised within a social-ecological model of health; that is, they operate across individual, interpersonal, environmental, organisational and policy levels. The novel finding of this review was the re-occurrence of similar influences across multiple healthcare service settings in Australia. The prevalence and re-occurring nature of the social determinants of health suggests that refugees are experiencing multilayered barriers to accessing Australian healthcare. All levels of a social-ecological model must be addressed in any attempt to break down these barriers.
Ethylene promotes root hair growth through coordinated EIN3/EIL1 and RHD6/RSL1 activity in
Arabidopsis
Authors: Feng Ying , Xu Ping , Li Bosheng , Li Pengpeng , Wen Xing , An Fengying , Gong Yan , Xin Yi , Zhu Ziqiang , Wang Yichuan , Guo Hongwei
Published: December 2017

Significance

Root hairs are unicellular extensions of root epidermal cells that help plants increase water and nutrient uptake and improve soil anchorage, both of which are crucial for the globally recognized goal of yield improvement with reduced fertilizer use. Previous studies have implicated numerous genes and phytohormones in the control of root hair development. This work uncovers the molecular mechanism of ethylene (ET)-promoted root hair growth and identifies a transcriptional complex consisting of EIN3/EIL1 and RHD6/RSL1 as the key regulator of root hair initiation and elongation. As ET mediates the effects of various root hair stimuli, this work also elucidates a convergent signaling network that integrates diverse environmental cues and intrinsic signals to modulate plant organ development.
Transient receptor potential channel 6 regulates abnormal cardiac S-nitrosylation in Duchenne muscular dystrophy
Authors: Chung Heaseung Sophia , Kim Grace E. , Holewinski Ronald J. , Venkatraman Vidya , Zhu Guangshuo , Bedja Djahida , Kass David A. , Van Eyk Jennifer E.
Published: December 2017

Significance

The pathological Duchenne muscular dystrophy (DMD) muscles show increased stretch-induced intracellular Ca
2+
and nitrosative stress. Whether there is a link between the two, and how the former impacts the nitrosylated proteome, is unknown. Here, we report that transient receptor potential channel 6 (Trpc6) modulates increased nitrosative stress in dmd
mdx
:utrn
+/−
mice, as reflected by an increase in protein S-nitrosylation, and provide a broad high-throughput analysis of S-nitrosylation in this model. We found that S-nitrosothiol targets are conserved in dmd
mdx
:utrn
+/−
myocardium, but intensified in a Trpc6-dependent manner. Restoration of more normal S-nitrosylation profiles in dmd
mdx
:utrn
+/−
mouse hearts lacking Trpc6 corresponds to improved cardiac function and reduced fibrosis. These findings link Trpc6-mediated Ca
2+
signaling and nitrosative stress in the redox pathobiology of DMD.
Making two-photon processes dominate one-photon processes using mid-IR phonon polaritons
Authors: Rivera Nicholas , Rosolen Gilles , Joannopoulos John D. , Kaminer Ido , Soljačić Marin
Published: December 2017

Significance

The recent discovery of nanoscale-confined phonon polaritons in polar dielectric materials has generated vigorous interest because it provides a path to low-loss nanoscale photonics at technologically important mid-IR and terahertz frequencies. In this work, we show that these polar dielectrics can be used to develop a bright and efficient spontaneous emitter of photon pairs. The two-photon emission can completely dominate the total emission for realistic electronic systems, even when competing single-photon emission channels exist. We believe this work acts as a starting point for the development of sources of entangled nano-confined photons at frequency ranges where photon sources are generally considered lacking. Additionally, we believe that these results add a dimension to the great promise of phonon polaritonics.
Bulk magnetic domain stability controls paleointensity fidelity
Authors: Paterson Greig A. , Muxworthy Adrian R. , Yamamoto Yuhji , Pan Yongxin
Published: December 2017

Significance

The strength of the ancient geomagnetic field (paleointensity) is a key tool to observe the evolution of early Earth’s geodynamo, which provided an essential protective barrier for the emergence of life. However, paleointensity data are fraught with difficulties that make understanding the evolution of our planet more challenging. We demonstrate a long-sought-after quantitative relationship between fundamental rock magnetic properties and the fidelity of paleointensity records. This relationship can be used to reject low-fidelity paleointensity records and help resolve controversy that surrounds key questions about the evolution of our planet, such as when did the geodynamo begin, when did the inner core solidify, or how early life may have interacted with the magnetic field.
Misorientation dependence of grain boundary migration in advanced ultra-supercritical Ni-based superalloy
Authors: Li Huifang , Ye Fei , Zhao Jie , Cao Tieshan , Xu Fanghong , Xu Qingshuang , Wang Yan , Cheng Congqian , Min Xiaohua
Published: December 2017

The microstructures of a Ni-based superalloy used in the advanced ultra-supercritical condition were investigated after creep deformation. The grain boundary migrated during tertiary creep. Accompanied by the migration of grain boundaries, the coarsened γ′ phase with rodlike shape was formed and the precipitate-free zones emerged around this coarsened γ′. The distributional misorientation angle of these grain boundaries was from 45° to 65°. After the examination of the distribution characteristics of the cracks, it was found that the intergranular cracks did not propagate through the precipitate-free zones with the coarsened γ′.
Effect of preheating on the deformation in cold spraying
Authors: Sun Chengchuan , Zhou Xianglin , Xu Lingling , Xie Chen
Published: December 2017

In this research, the Eulerian method was used to simulate the relationship between the preheating temperature and the critical velocity. The size and shape of the void (no-material-existence zone) and the thickness of the model were investigated. Various preheating temperatures were used throughout the whole model. The critical velocity was determined with jet's appearance. The simulation results demonstrated the void size and shape influenced the results, although the thickness did not. The critical velocity decreased as the preheating temperature rose. The relationship between critical velocity and minimum preheating temperature when the jet formed appeared to be a linear relationship. The experimental results confirmed the simulation results. The linear equation could be used to predict the preheating temperature at a certain velocity below the critical value. The corresponding steady maximum PEEQ (equivalent plastic strain) value at the minimum preheating temperature could be divided into a stable type and a fluctuation type.
Using Carbon Dioxide in Fisheries and Aquatic Invasive Species Management
Authors: Treanor Hilary B. , Ray Andrew M. , Layhee Megan , Watten Barnaby J. , Gross Jackson A. , Gresswell Robert E. , Webb Molly A. H.
Published: December 2017

To restore native fish populations, fisheries programs often depend on active removal of aquatic invasive species. Chemical removal can be an effective method of eliminating aquatic invasive species, but chemicals can induce mortality in nontarget organisms and persist in the environment. Carbon dioxide (CO2) is an emerging alternative to traditional chemical control agents because it has been demonstrated to be toxic to fish, but is naturally occurring and readily neutralized. In addition, CO2 is a commercially available gas, is highly soluble, and has high absorption efficiency. When these characteristics are paired with advances in modern, large-scale gas delivery technologies, opportunities to use CO2 in natural or artificial (e.g., canals) waters to manage fish become increasingly feasible. Our objective is to describe the history of CO2 use in fisheries and outline potential future applications of CO2 to suppress and manipulate aquatic species in field and aquaculture settings.
Promoting solutions and co-constructing problems – management consultancy and instrument constituencies
Authors: Sturdy Andrew
Published: December 2017

The concept of ‘instrument constituencies’ has recently emerged in policy research to reflect actors and practices focused primarily on articulating and promoting policy solutions. A central component of this is that, with such an emphasis on promotion, policy-maker decisions are subject to supply push rather than being demand-led. In particular, the ‘solutions’ of instrument constituencies come before, rather than after, the problems they are held to solve – solutions chasing problems. Key actors here are external consultants. However, the extent to which their activities match the problem chasing of the instrument constituency concept is untested. As a start in addressing such neglect, this article draws on data from secondary sources from research, outside the policy field, in organisation studies. In particular, it compares promotional practices in consulting with the supply push element of the instrument constituency model, finding that they correspond, but only partially. Consultants do not always construct problems for their clients to fit their prepared solutions, nor do they simply conform to the conventional, ‘rational’ model. Rather, it is shown that they also simultaneously co-produce both problems and solutions with clients, combining supply-push and demand-led approaches. Thus, it is argued that the model need not be so strongly associated with problem chasing (and non-rational decisions). Rather, the case of consultancy draws attention to how decision-making through instrument constituencies can occur along a continuum of three positions, from problems pre-dating solutions, being (co-) constructed at the same time, to their production after the ‘solution’.
The concept of instrument constituencies: accounting for dynamics and practices of knowing governance
Authors: Simons Arno , Voß Jan-Peter
Published: December 2017

As a new concept in policy analysis, instrument constituencies shed light on the ‘supply side’ of policy-making and thereby fill a gap in our understanding of national and transnational policy dynamics. Policy instruments are not only ‘active’ because they contain scripts for reordering society but also because they gather a constituency comprised of practices and actors oriented towards developing, maintaining and expanding a specific instrumental model of governing. Instrument constituencies account for a hitherto neglected form of agency and explain the often-observed paradox that policy solutions sometimes chase policy problems, although the former are meant to emerge as answers to the later. We give an outline of the concept as it has been developed so far, formulate propositions, and discuss linkages with established research traditions in policy studies.
DICER- and MMSET-catalyzed H4K20me2 recruits the nucleotide excision repair factor XPA to DNA damage sites
Authors: Chitale Shalaka , Richly Holger
Published: December 2017

Ultraviolet (UV) irradiation triggers the recruitment of DNA repair factors to the lesion sites and the deposition of histone marks as part of the DNA damage response. The major DNA repair pathway removing DNA lesions caused by exposure to UV light is nucleotide excision repair (NER). We have previously demonstrated that the endoribonuclease DICER facilitates chromatin decondensation during lesion recognition in the global-genomic branch of NER. Here, we report that DICER mediates the recruitment of the methyltransferase MMSET to the DNA damage site. We show that MMSET is required for efficient NER and that it catalyzes the dimethylation of histone H4 at lysine 20 (H4K20me2). H4K20me2 at DNA damage sites facilitates the recruitment of the NER factor XPA. Our work thus provides evidence for an H4K20me2-dependent mechanism of XPA recruitment during lesion recognition in the global-genomic branch of NER.
DepHining membrane identity
Authors: Hammond Gerald R.V.
Published: December 2017

How do organelles coordinate their unique molecular identities between their cytosolic-facing surface membranes and their interior? In this issue, Naufer et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201702179) discover an intriguing link between phagosome acidification and lipid signposts on their outer membrane.
A perspective on Na and K channel inactivation
Authors: Armstrong Clay M. , Hollingworth Stephen
Published: December 2017

We are wired with conducting cables called axons that rapidly transmit electrical signals (e.g., “Ouch!”) from, for example, the toe to the spinal cord. Because of the high internal resistance of axons (salt water rather than copper), a signal must be reinforced after traveling a short distance. Reinforcement is accomplished by ion channels, Na channels for detecting the signal and reinforcing it by driving it further positive (to near 50 mV) and K channels for then restoring it to the resting level (near −70 mV). The signal is called an action potential and has a duration of roughly a millisecond. The return of membrane voltage (Vm) to the resting level after an action potential is facilitated by “inactivation” of the Na channels: i.e., an internal particle diffuses into the mouth of any open Na channel and temporarily blocks it. Some types of K channels also show inactivation after being open for a time. N-type inactivation of K channels has a relatively fast time course and involves diffusion of the N-terminal of one of the channel’s four identical subunits into the channel’s inner mouth, if it is open. This mechanism is similar to Na channel inactivation. Both Na and K channels also display slower inactivation processes. C inactivation in K channels involves changes in the channel’s outer mouth, the “selectivity filter,” whose normal function is to prevent Na+ ions from entering the K channel. C inactivation deforms the filter so that neither K+ nor Na+ can pass.
Revisiting multimodal activation and channel properties of Pannexin 1
Authors: Chiu Yu-Hsin , Schappe Michael S. , Desai Bimal N. , Bayliss Douglas A.
Published: December 2017

Pannexin 1 (Panx1) forms plasma membrane ion channels that are widely expressed throughout the body. Panx1 activation results in the release of nucleotides such as adenosine triphosphate and uridine triphosphate. Thus, these channels have been implicated in diverse physiological and pathological functions associated with purinergic signaling, such as apoptotic cell clearance, blood pressure regulation, neuropathic pain, and excitotoxicity. In light of this, substantial attention has been directed to understanding the mechanisms that regulate Panx1 channel expression and activation. Here we review accumulated evidence for the various activation mechanisms described for Panx1 channels and, where possible, the unitary channel properties associated with those forms of activation. We also emphasize current limitations in studying Panx1 channel function and propose potential directions to clarify the exciting and expanding roles of Panx1 channels.
Structural insights into the mechanisms of CNBD channel function
Authors: James Zachary M. , Zagotta William N.
Published: December 2017

Cyclic nucleotide-binding domain (CNBD) channels are a family of ion channels in the voltage-gated K+ channel superfamily that play crucial roles in many physiological processes. CNBD channels are structurally similar but functionally very diverse. This family includes three subfamilies: (1) the cyclic nucleotide-gated (CNG) channels, which are cation-nonselective, voltage-independent, and cyclic nucleotide-gated; (2) the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are weakly K+ selective, hyperpolarization-activated, and cyclic nucleotide-gated; and (3) the ether-à-go-go-type (KCNH) channels, which are strongly K+ selective, depolarization-activated, and cyclic nucleotide-independent. Recently, several high-resolution structures have been reported for intact CNBD channels, providing a structural framework to better understand their diverse function. In this review, we compare and contrast the recent structures and discuss how they inform our understanding of ion selectivity, voltage-dependent gating, and cyclic nucleotide–dependent gating within this channel family.
CFD Analysis in Subsea and Marine Technology
Authors: Jasak Hrvoje
Published: December 2017

Computational Fluid Dynamics (CFD) is established in design and analysis for a range of industries, but its use in Marine and Naval Hydrodynamics is behind the trend. This can be attributed to the complexity of modelling needs, including presence of free surface,
irregular transient flows, fluid-structure coupling and presence of established modelling tools based on potential theory.

In this paper, state-of-the-art of CFD in Naval Hydrodynamics, wave and offshore applications is given, with an update of recent advances, validation and computing requirements for typical simulation cases.