bluuebunny/crossref_metadata_2025 huggingface dataset:
Classification of Hamiltonians in neighborhoods of band crossings in terms of the theory of singularities
Authors: Teramoto Hiroshi , Kondo Kenji , Izumiya Shyūichi , Toda Mikito , Komatsuzaki Tamiki
Published: July 2017

We classify two-by-two traceless Hamiltonians depending smoothly on a three-dimensional Bloch wavenumber and having a band crossing at the origin of the wavenumber space. Recently these Hamiltonians attract much interest among researchers in the condensed matter field since they are found to be effective Hamiltonians describing the band structure of the exotic materials such as Weyl semimetals. In this classification, we regard two such Hamiltonians as equivalent if there are appropriate special unitary transformation of degree 2 and diffeomorphism in the wavenumber space fixing the origin such that one of the Hamiltonians transforms to the other. Based on the equivalence relation, we obtain a complete list of classes up to codimension 7. For each Hamiltonian in the list, we calculate multiplicity and Chern number [D. J. Thouless et al., Phys. Rev. Lett. 49, 405 (1982); M. V. Berry, Proc. R. Soc. A 392, 45 (1983); and B. Simon, Phys. Rev. Lett. 51, 2167 (1983)], which are invariant under an arbitrary smooth deformation of the Hamiltonian. We also construct a universal unfolding for each Hamiltonian and demonstrate how they can be used for bifurcation analysis of band crossings.
NanoRocks: Design and performance of an experiment studying planet formation on the International Space Station
Authors: Brisset Julie , Colwell Joshua , Dove Adrienne , Maukonen Doug
Published: July 2017

In an effort to better understand the early stages of planet formation, we have developed a 1.5U payload that flew on the International Space Station (ISS) in the NanoRacks NanoLab facility between September 2014 and March 2016. This payload, named NanoRocks, ran a particle collision experiment under long-term microgravity conditions. The objectives of the experiment were (a) to observe collisions between mm-sized particles at relative velocities of < 1 cm/s and (b) to study the formation and disruption of particle clusters for different particle types and collision velocities. Four types of particles were used: mm-sized acrylic, glass, and copper beads and 0.75 mm-sized JSC-1 lunar regolith simulant grains. The particles were placed in sample cells carved out of an aluminum tray. This tray was attached to one side of the payload casing with three springs. Every 60 s, the tray was agitated, and the resulting collisions between the particles in the sample cells were recorded by the experiment camera. During the 18 months the payload stayed on ISS, we obtained 158 videos, thus recording a great number of collisions. The average particle velocities in the sample cells after each shaking event were around 1 cm/s. After shaking stopped, the inter-particle collisions damped the particle kinetic energy in less than 20 s, reducing the average particle velocity to below 1 mm/s, and eventually slowing them to below our detection threshold. As the particle velocity decreased, we observed the transition from bouncing to sticking collisions. We recorded the formation of particle clusters at the end of each experiment run. This paper describes the design and performance of the NanoRocks ISS payload.
Local factorisation of the dynamics of quantum spin systems
Authors: Bachmann Sven , Bluhm Andreas
Published: July 2017

Motivated by the study of area laws for the entanglement entropy of gapped ground states of quantum spin systems and their stability, we prove that the unitary cocycle generated by a local time-dependent Hamiltonian can be approximated, for any finite set X, by a tensor product of the corresponding unitaries in X and its complement, multiplied by a dynamics strictly supported in the neighbourhood of the surface ∂X. The error decays almost exponentially in the size of the neighbourhood and grows with the square of the area |∂X|2.
Partial wave decomposition in Friedrichs model with self-interacting continua
Authors: Xiao Zhiguang , Zhou Zhi-Yong
Published: July 2017

We consider the nonrelativistic model of coupling bare discrete states with continuum states in which the continuum states can have interactions among themselves. By partial-wave decomposition and constraint to the conserved angular momentum eigenstates, the model can be reduced to Friedrichs-like model with additional interactions between the continua. If a kind of factorizable form factor is chosen, the model can be exactly solvable, that is, the generalized discrete eigenstates including bound states, virtual states, and resonances can all be represented using the original bare states, and so do the in-state and out-state. The exact S matrix is thus obtained. We then discuss the behaviors of the dynamically generated S-wave and P-wave discrete states as the coupling is varying when there is only one self-interacting bare continuum state. We find that even when the potential is repulsive there could also be resonances and virtual states. In the P-wave cases with attractive interaction, we find that when there is a near-threshold bound state, there will always be an accompanying virtual state and we also give a more general argument of this effect.
On the representation theory of the Bondi–Metzner–Sachs group and its variants in three space–time dimensions
Authors: Melas Evangelos
Published: July 2017

The original Bondi–Metzner–Sachs (BMS) group B is the common asymptotic symmetry group of all asymptotically flat Lorentzian radiating 4-dim space–times. As such, B is the best candidate for the universal symmetry group of General Relativity (G.R.). In 1973, with this motivation, McCarthy classified all relativistic B-invariant systems in terms of strongly continuous irreducible unitary representations (IRS) of B. Here we introduce the analogue B(2, 1) of the BMS group B in 3 space–time dimensions. B(2, 1) itself admits thirty-four analogues both real in all signatures and in complex space–times. In order to find the IRS of both B(2, 1) and its analogues, we need to extend Wigner–Mackey’s theory of induced representations. The necessary extension is described and is reduced to the solution of three problems. These problems are solved in the case where B(2, 1) and its analogues are equipped with the Hilbert topology. The extended theory is necessary in order to construct the IRS of both B and its analogues in any number d of space–time dimensions, d≥3, and also in order to construct the IRS of their supersymmetric counterparts. We use the extended theory to obtain the necessary data in order to construct the IRS of B(2, 1). The main results of the representation theory are as follows: The IRS are induced from “little groups” which are compact. The finite “little groups” are cyclic groups of even order. The inducing construction is exhaustive notwithstanding the fact that B(2, 1) is not locally compact in the employed Hilbert topology.
Toward chemical accuracy in the description of ion–water interactions through many-body representations. Alkali-water dimer potential energy surfaces
Authors: Riera Marc , Mardirossian Narbe , Bajaj Pushp , Götz Andreas W. , Paesani Francesco
Published: July 2017

This study presents the extension of the MB-nrg (Many-Body energy) theoretical/computational framework of transferable potential energy functions (PEFs) for molecular simulations of alkali metal ion-water systems. The MB-nrg PEFs are built upon the many-body expansion of the total energy and include the explicit treatment of one-body, two-body, and three-body interactions, with all higher-order contributions described by classical induction. This study focuses on the MB-nrg two-body terms describing the full-dimensional potential energy surfaces of the M+(H2O) dimers, where M+ = Li+, Na+, K+, Rb+, and Cs+. The MB-nrg PEFs are derived entirely from “first principles” calculations carried out at the explicitly correlated coupled-cluster level including single, double, and perturbative triple excitations [CCSD(T)-F12b] for Li+ and Na+ and at the CCSD(T) level for K+, Rb+, and Cs+. The accuracy of the MB-nrg PEFs is systematically assessed through an extensive analysis of interaction energies, structures, and harmonic frequencies for all five M+(H2O) dimers. In all cases, the MB-nrg PEFs are shown to be superior to both polarizable force fields and ab initio models based on density functional theory. As previously demonstrated for halide-water dimers, the MB-nrg PEFs achieve higher accuracy by correctly describing short-range quantum-mechanical effects associated with electron density overlap as well as long-range electrostatic many-body interactions.
Spin-up flow in non-small magnetic fields: Numerical evaluation of the predictions of the common magnetization relaxation equations
Authors: Chaves-Guerrero Arlex , Peña-Cruz Víctor A. , Rinaldi Carlos , Fuentes-Díaz David
Published: July 2017

The flow of a ferrofluid between two parallel infinitely long plates generated by a rotating magnetic field has been studied analytically and numerically using spin diffusion theory for a broad range of frequencies and intensities of the magnetic field. This work was motivated by interest in obtaining better agreement between the theoretical predictions and the experimental observations of the dependence of the flow magnitude on the amplitude and frequency of the magnetic field. These discrepancies have been attributed to the use of asymptotic solutions to assess velocity profiles obtained to moderate magnetic field strength and to the need to use a more accurate magnetization equation to high amplitudes and frequencies of the magnetic field. For such reasons, the objective of this work was to evaluate the effect of the magnetization equations derived by Shliomis [Sov. Phys. JETP 34, 1291 (1972)] (Sh-72) and by Martsenyuk, Raikher, and Shliomis [Sov. Phys. JETP 38, 413 (1974)] (MRSh-74) on the flow predictions of the spin diffusion theory using a simple geometry. It was found that the flow predictions for the two cases studied match with an asymptotic solution in the limit of low field strength when the Langevin parameter α is less than 0.1, for any value of the dimensionless frequency (Ω̃). Marked differences were found in the predictions of flow magnitude dependence on the amplitude and frequency of the magnetic field when Sh-72 or MRSh-74 was used for α>1. Results also show that there is a critical value of frequency above which the velocity of the ferrofluid decreases with increasing magnetic field amplitude. Whereas the value of the critical frequency predicted by the Sh-72 magnetization equation is approximately unity for any value of the magnetic field amplitude, the MRSh-74 equation predicts that the critical frequency increases with increasing magnetic field amplitude. Predictions of the MRSh-74 equation are in qualitative agreement with previously reported experimental velocity profiles in other geometries.
Valence electronic structure of cobalt phthalocyanine from an optimally tuned range-separated hybrid functional
Authors: Brumboiu Iulia Emilia , Prokopiou Georgia , Kronik Leeor , Brena Barbara
Published: July 2017

We analyse the valence electronic structure of cobalt phthalocyanine (CoPc) by means of optimally tuning a range-separated hybrid functional. The tuning is performed by modifying both the amount of short-range exact exchange (α) included in the hybrid functional and the range-separation parameter (γ), with two strategies employed for finding the optimal γ for each α. The influence of these two parameters on the structural, electronic, and magnetic properties of CoPc is thoroughly investigated. The electronic structure is found to be very sensitive to the amount and range in which the exact exchange is included. The electronic structure obtained using the optimal parameters is compared to gas-phase photo-electron data and GW calculations, with the unoccupied states additionally compared with inverse photo-electron spectroscopy measurements. The calculated spectrum with tuned γ, determined for the optimal value of α = 0.1, yields a very good agreement with both experimental results and with GW calculations that well-reproduce the experimental data.
Visualizing dispersive features in 2D image via minimum gradient method
Authors: He Yu , Wang Yan , Shen Zhi-Xun
Published: July 2017

We developed a minimum gradient based method to track ridge features in a 2D image plot, which is a typical data representation in many momentum resolved spectroscopy experiments. Through both analytic formulation and numerical simulation, we compare this new method with existing DC (distribution curve) based and higher order derivative based analyses. We find that the new method has good noise resilience and enhanced contrast especially for weak intensity features and meanwhile preserves the quantitative local maxima information from the raw image. An algorithm is proposed to extract 1D ridge dispersion from the 2D image plot, whose quantitative application to angle-resolved photoemission spectroscopy measurements on high temperature superconductors is demonstrated.
Derivatives of Horn hypergeometric functions with respect to their parameters
Authors: Ancarani L. U. , Del Punta J. A. , Gasaneo G.
Published: July 2017

The derivatives of eight Horn hypergeometric functions [four Appell F1, F2, F3, and F4, and four (degenerate) confluent Φ1, Φ2, Ψ1, and Ξ1] with respect to their parameters are studied. The first derivatives are expressed, systematically, as triple infinite summations or, alternatively, as single summations of two-variable Kampé de Fériet functions. Taking advantage of previously established expressions for the derivative of the confluent or Gaussian hypergeometric functions, the generalization to the nth derivative of Horn’s functions with respect to their parameters is rather straightforward in most cases; the results are expressed in terms of n + 2 infinite summations. Following a similar procedure, mixed derivatives are also treated. An illustration of the usefulness of the derivatives of F1, with respect to the first and third parameters, is given with the study of autoionization of atoms occurring as part of a post-collisional process. Their evaluation setting the Coulomb charge to zero provides the coefficients of a Born-like expansion of the interaction.
The solution structure of the O(3) sigma model in a Maxwell-Chern-Simons theory
Authors: Yang Sze-Guang , Chen Zhi-You , Chern Jann-Long
Published: July 2017

In this paper, a system of semilinear elliptic equations arising from a relativistic self-dual Maxwell-Chern-Simons O(3) sigma model is considered. We reveal the uniqueness aspect of the topological solutions for the model. The uniqueness result is associated with a clear solution structure of the equations of the radially symmetric case. We locate each solution set denoted by a planar diagram.
Local well-posedness of non-abelian Chern-Simons-Higgs system in the Lorenz gauge
Authors: Yuan Jianjun
Published: July 2017

In this paper, we consider the non-abelian Chern-Simons-Higgs system in the Lorenz gauge. By exploiting the null structure of the system and using the Xs,b type spaces, we give a local well-posedness result of it.
Time domain simulation of Gd3+–Gd3+ distance measurements by EPR
Authors: Manukovsky Nurit , Feintuch Akiva , Kuprov Ilya , Goldfarb Daniella
Published: July 2017

Gd3+-based spin labels are useful as an alternative to nitroxides for intramolecular distance measurements at high fields in biological systems. However, double electron-electron resonance (DEER) measurements using model Gd3+ complexes featured a low modulation depth and an unexpected broadening of the distance distribution for short Gd3+–Gd3+ distances, when analysed using the software designed for S = 1/2 pairs. It appears that these effects result from the different spectroscopic characteristics of Gd3+—the high spin, the zero field splitting (ZFS), and the flip-flop terms in the dipolar Hamiltonian that are often ignored for spin-1/2 systems. An understanding of the factors affecting the modulation frequency and amplitude is essential for the correct analysis of Gd3+–Gd3+ DEER data and for the educated choice of experimental settings, such as Gd3+ spin label type and the pulse parameters. This work uses time-domain simulations of Gd3+–Gd3+ DEER by explicit density matrix propagation to elucidate the factors shaping Gd3+ DEER traces. The simulations show that mixing between the |+½, −½〉 and |−½, +½〉 states of the two spins, caused by the flip-flop term in the dipolar Hamiltonian, leads to dampening of the dipolar modulation. This effect may be mitigated by a large ZFS or by pulse frequency settings allowing for a decreased contribution of the central transition and the one adjacent to it. The simulations reproduce both the experimental line shapes of the Fourier-transforms of the DEER time domain traces and the trends in the behaviour of the modulation depth, thus enabling a more systematic design and analysis of Gd3+ DEER experiments.
Cryopump development of the 5 MW neutral beam injector system on HL-2M tokamak
Authors: Yang Xianfu , Cao Jianyong , Liu He , Wei Huiling , Liu Weicheng , Ma Hong
Published: July 2017

In order to carry out the long pulse and high power neutral beam injector (NBI) heating experiment on the HL-2M tokamak and satisfy its high vacuum pumping speed in the NBI, two built-in cryopumps with large area and based on a three-stage adsorption structure have been developed. The design idea and size of the three stage structure, the manufacturing technique, and the test experiment for cryopumps have been described in this paper. The experimental result shows that the cooldown time of liquid nitrogen pipes and liquid helium pipes are 1.5 h and 10 min, respectively. With activated charcoal bonded on the condensation plates, the pumping speed reaches 1.13 × 106 l/s, and the consumption of liquid helium is 2.53 g/s and 3.11 g/s for the 4-component pump and the 5-component pump, respectively. The conductance probability of the pump inlet is 0.25 for hydrogen.
Power dissipation in fractal Feynman-Sierpinski AC circuits
Authors: Alonso Ruiz Patricia
Published: July 2017

This paper studies the concept of power dissipation in infinite graphs and fractals associated with passive linear networks consisting of non-dissipative elements. In particular, we analyze the so-called Feynman-Sierpinski ladder, a fractal AC circuit motivated by Feynman’s infinite ladder, that exhibits power dissipation and wave propagation for some frequencies. Power dissipation in this circuit is obtained as a limit of quadratic forms, and the corresponding power dissipation measure associated with harmonic potentials is constructed. The latter measure is proved to be continuous and singular with respect to an appropriate Hausdorff measure defined on the fractal dust of nodes of the network.
Shallow water dynamics on linear shear flows and plane beaches
Authors: Bjørnestad Maria , Kalisch Henrik
Published: July 2017

Long waves in shallow water propagating over a background shear flow towards a sloping beach are being investigated. The classical shallow-water equations are extended to incorporate both a background shear flow and a linear beach profile, resulting in a non-reducible hyperbolic system. Nevertheless, it is shown how several changes of variables based on the hodograph transform may be used to transform the system into a linear equation which may be solved exactly using the method of separation of variables. This method can be used to investigate the run-up of a long wave on a planar beach including the development of the waterline.
Diffractive refractometer for liquid characterization and transient processes monitoring
Authors: Barbosa E. A. , Dib L. F. G.
Published: July 2017

A simple refractometer using a reflective diffraction grating immersed in the test liquid is developed and its performance is studied. Due to the dependence of the light wavelength on the refractive index, determining the angle of the diffracted beam provides the refractive index of the liquid. The glass cell containing the test liquid is cylindrical, and the grating plane is parallel to the cylinder symmetry axis. The light beam normally impinges on the cell front wall and reaches the center of the grating so that the diffracted beam leaves the cell without being deviated by refraction. It is demonstrated that this characteristic of the optical setup minimizes important error sources due to undesired beam deviations and enables real-time refractive index measurement of liquids in transient processes. Moreover, the performances of the diffractive refractometer and of a commercial Abbe refractometer are compared in the measurement of the refractive indexes of aqueous NaCl solutions. A He–Ne laser at 632.8 nm is used as a light source, and the diffraction grating has 1200 lines/mm. Measurement precisions of the order of 8 × 10−4 are achieved.
Microcantilever array instrument based on optical fiber and performance analysis
Authors: Zhang Guangping , Wu Lin , Li Chao , Wu Shangquan , Zhang Qingchuan
Published: July 2017

We developed a microcantilever array biosensor instrument based on optical readout from a microcantilever array in fluid environment. The microcantilever signals were read out sequentially by laser beams emitted from eight optical fibers. The optical fibers were coupled to lasers, while the other ends of the fibers were embedded in eight V-grooves with 250 μm pitch microfabricated from a Si wafer. Aspherical lens was used to keep the distance between lasers. A programmable logic controller was used to make the system work stably. To make sure that the output of lasers was stable, a temperature controller was set up for each laser. When the deflection signal was collected, lasers used here were set to be on for at least 400 ms in each scanning cycle to get high signal-to-noise ratio deflection curves. A test was performed by changing the temperature of the liquid cell holding a microcantilever array to verify the consistent response of the instrument to the cantilever deflections. The stability and conformance of the instrument were demonstrated by quantitative detection of mercury ions in aqueous solution and comparison detection of clenbuterol by setting test and reference cantilevers. This microcantilever array detection instrument can be applied to highly sensitive detection of chemical and biological molecules in fluid environment.
Single shot ultrafast all optical magnetization switching of ferromagnetic Co/Pt multilayers
Authors: Gorchon Jon , Lambert Charles-Henri , Yang Yang , Pattabi Akshay , Wilson Richard B. , Salahuddin Sayeef , Bokor Jeffrey
Published: July 2017

A single femto-second optical pulse can fully reverse the magnetization of a film within picoseconds. Such fast operation hugely increases the range of application of magnetic devices. However, so far, this type of ultrafast switching has been restricted to ferri-magnetic GdFeCo films. In contrast, all optical switching of ferro-magnetic films require multiple pulses, thereby being slower and less energy efficient. Here, we demonstrate magnetization switching induced by a single laser pulse in various ferromagnetic Co/Pt multilayers grown on GdFeCo, by exploiting the exchange coupling between the two magnetic films. Table-top depth-sensitive time-resolved magneto-optical experiments show that the Co/Pt magnetization switches within 7 ps. This coupling approach will allow ultrafast control of a variety of magnetic films, which is critical for applications.
Ferromagnetism in graphene due to charge transfer from atomic Co to graphene
Authors: Hota Poulami , Akhtar Abu Jahid , Bhattacharya Shatabda , Miah Milon , Saha Shyamal K.
Published: July 2017

The charge transfer effect at the graphene/transition metal interface has been studied extensively during the last few years; however, the experimental results are very poor. In the present work, a Co atom capped with porphyrin is attached on the graphene surface to realize the induced magnetic properties arising due to the charge transfer effect at the interface. Ferromagnetic ordering with fairly large coercivity (516 Oe) is observed as a result of this induced magnetism in graphene due to the presence of a transition metal atom on the graphene surface. Temperature dependent magnetotransport has also been investigated to understand the effect of spin-orbit coupling arising due to the electric field generated at the interface as a result of this charge transfer effect.
Modeling of toroidal torques exerted by internal kink instability in a tokamak plasma
Authors: Zhang N. , Liu Y. Q. , Yu D. L. , Wang S. , Xia G. L. , Dong G. Q. , Bai X.
Published: July 2017

Toroidal modeling efforts are initiated to systematically compute and compare various toroidal torques, exerted by an unstable internal kink in a tokamak plasma, using the MARS-F/K/Q suite of codes. The torques considered here include the resonant electromagnetic torque due to the Maxwell stress (the EM or JXB torque), the neoclassical toroidal viscous (NTV) torque, and the torque associated with the Reynolds stress. Numerical results show that the relative magnitude of the net resonant electromagnetic and the Reynolds stress torques increases with the equilibrium flow speed of the plasma, whilst the net NTV torque follows the opposite trend. The global flow shear sensitively affects the Reynolds stress torque, but not the electromagnetic and the NTV torques. Detailed examinations reveal dominant contributions to the Maxwell and Reynolds stress torques, in terms of the poloidal harmonic numbers of various perturbation fields, as well as their relative toroidal phasing.
Intrinsic p-type W-based transition metal dichalcogenide by substitutional Ta-doping
Authors: Fu Yajun , Long Mingsheng , Gao Anyuan , Wang Yu , Pan Chen , Liu Xiaowei , Zeng Junwen , Xu Kang , Zhang Lili , Liu Erfu , Hu Weida , Wang Xiaomu , Miao Feng
Published: July 2017

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have recently emerged as promising candidates for future electronics and optoelectronics. While most of TMDs are intrinsic n-type semiconductors due to electron donating which originates from chalcogen vacancies, obtaining intrinsic high-quality p-type semiconducting TMDs has been challenging. Here, we report an experimental approach to obtain intrinsic p-type Tungsten (W)-based TMDs by substitutional Ta-doping. The obtained few-layer Ta-doped WSe2 (Ta0.01W0.99Se2) field-effect transistor devices exhibit competitive p-type performances, including ∼106 current on/off at room temperature. We also demonstrate high quality van der Waals (vdW) p-n heterojunctions based on Ta0.01W0.99Se2/MoS2 structure, which exhibit nearly ideal diode characteristics (with an ideality factor approaching 1 and a rectification ratio up to 1 × 105) and excellent photodetecting performance. Our study suggests that substitutional Ta-doping holds great promise to realize intrinsic p-type W-based TMDs for future electronic and photonic applications.
Thermal characterization of polycrystalline diamond thin film heat spreaders grown on GaN HEMTs
Authors: Zhou Yan , Ramaneti Rajesh , Anaya Julian , Korneychuk Svetlana , Derluyn Joff , Sun Huarui , Pomeroy James , Verbeeck Johan , Haenen Ken , Kuball Martin
Published: July 2017

Polycrystalline diamond (PCD) was grown onto high-k dielectric passivated AlGaN/GaN-on-Si high electron mobility transistor (HEMT) structures, with film thicknesses ranging from 155 to 1000 nm. Transient thermoreflectance results were combined with device thermal simulations to investigate the heat spreading benefit of the diamond layer. The observed thermal conductivity (κDia) of PCD films is one-to-two orders of magnitude lower than that of bulk PCD and exhibits a strong layer thickness dependence, which is attributed to the grain size evolution. The films exhibit a weak temperature dependence of κDia in the measured 25–225 °C range. Device simulation using the experimental κDia and thermal boundary resistance values predicts at best a 15% reduction in peak temperature when the source-drain opening of a passivated AlGaN/GaN-on-Si HEMT is overgrown with PCD.
“Feathered” fractal surfaces to minimize secondary electron emission for a wide range of incident angles
Authors: Swanson Charles , Kaganovich Igor D.
Published: July 2017

Complex structures on a material surface can significantly reduce the total secondary electron emission from that surface. The reduction occurs due to the capture of low-energy, true secondary electrons emitted at one point of the structure and intersecting another. We performed Monte Carlo calculations to demonstrate that fractal surfaces can reduce net secondary electron emission produced by the surface as compared to the flat surface. Specifically, we describe one surface, a “feathered” surface, which reduces the secondary electron emission yield more effectively than other previously considered configurations. Specifically, feathers grown onto a surface suppress secondary electron emission from shallow angles of incidence more effectively than velvet. We find that, for the surface simulated, secondary electron emission yield remains below 20% of its un-suppressed value, even for shallow incident angles, where the velvet-only surface gives reduction factor of only 50%.
Color mixing from monolithically integrated InGaN-based light-emitting diodes by local strain engineering
Authors: Chung Kunook , Sui Jingyang , Demory Brandon , Ku Pei-Cheng
Published: July 2017

Additive color mixing across the visible spectrum was demonstrated from an InGaN based light-emitting diode (LED) pixel comprising red, green, and blue subpixels monolithically integrated and enabled by local strain engineering. The device was fabricated using a top-down approach on a metal-organic chemical vapor deposition-grown sample consisting of a typical LED epitaxial stack. The three color subpixels were defined in a single lithographic step. The device was characterized for its electrical properties and emission spectra under an uncooled condition, which is desirable in practical applications. The color mixing was controlled by pulse-width modulation, and the degree of color control was also characterized.
A capacitive ultrasonic transducer based on parametric resonance
Authors: Surappa Sushruta , Satir Sarp , Levent Degertekin F.
Published: July 2017

A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of fo. When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2fo with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at fo frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.
Space charge polarization modulated instability of low frequency permittivity in CaCu3Ti4O12 ceramics
Authors: Wu Kangning , Huang Yuwei , Li Jianying , Li Shengtao
Published: July 2017

A low frequency dielectric relaxation process of CaCu3Ti4O12 ceramics, which is generally overlapped by dc conduction in traditional dielectric spectra, is detected and clarified based on an improved analytical methodology in this letter. This relaxation process remarkably contributes to instability of low frequency permittivity and it clearly demonstrates the correlation between charge migration and space charge polarization. It is revealed that conduction will be achieved if carriers migrate and combine in the electrodes, while space charge polarization will be achieved if carriers migrate to the electrodes without combination.
Tunable electron affinity with electronic band alignment of solution processed dielectric
Authors: Mondal Sandip , Venkataraman V.
Published: July 2017

We report the tunability of the electronic band structure, especially the electron affinity, of an all-inorganic precursor processed sol-gel aluminium oxide phosphate dielectric by the influence of processing temperature. The dielectric offers tunable electron affinity ranging from 1.42 eV to 0.72 eV with the change in processing temperature from as-prepared to 1000 °C, respectively. The remarkable change in electron affinity is ascribed to the variation in the bulk oxygen concentration in solution processed oxide. As a result, the leakage current of the dielectric is affected significantly by a factor of ∼103.
Graphene membrane as a pressure gauge
Authors: Milovanović S. P. , Tadić M. Ž. , Peeters F. M.
Published: July 2017

Straining graphene results in the appearance of a pseudo-magnetic field which alters its local electronic properties. Applying a pressure difference between the two sides of the membrane causes it to bend/bulge resulting in a resistance change. We find that the resistance changes linearly with pressure for bubbles of small radius while the response becomes non-linear for bubbles that stretch almost to the edges of the sample. This is explained as due to the strong interference of propagating electronic modes inside the bubble. Our calculations show that high gauge factors can be obtained in this way which makes graphene a good candidate for pressure sensing.
Evolution of Korean honorifics
Authors: Sohn Ho-min
Published: July 2017

The aim of the present paper is to revisit earlier studies on the evolution of Korean honorifics and, following a brief survey of the contemporary system, (a) overview the historical development of Korean honorific patterns from Old Korean to Contemporary Korean and (b) propose to account, on a principled basis, for the evolutional processes in the framework of grammaticalization. I assume that Korean honorifics have evolved due essentially to the three interdependent language/culture-specific forces: structural, socio-cultural, and interactional, as directed by the language-universal principles and processes of grammaticalization. The essence of the structural forces is the agglutinative, predicate-final, and head-final morpho-syntactic nature of Korean. This typological salience is a crucial condition under which honorific affixes and particles may be germinated. Socio-cultural forces include the Korean people’s traditional and contemporary socio-cultural systems, values, and norms of hierarchism and collectivism, as language is regarded as reflecting culture and society. Koreans’ hierarchism and collectivism are sufficiently manifested in the structure and use of the language (e.g. H. Sohn 1986). The interactional forces are Koreans’ society/culture/context-bound interpersonal language use for communicative purposes. These three interlocking forces are assumed to have motivated and sustained a dynamic set of addressee and referent honorific contrasts in Korean, which have evolved as driven by the universal principles and processes of grammaticalization.
Expressive, social and gendered meanings of Korean honorifics
Authors: Brown Lucien
Published: July 2017

Traditional research on Korean honorifics has tended to assume that these forms have fixed meanings such as deference and respect. In this paper, I argue that such meanings only represent the most prototypical and normative expressive meanings of honorific forms. By surveying recent pragmatics and sociolinguistic research, I show how honorifics can communicate a variety of context-specific affective meanings. Some of these meanings, such as sarcasm and factuality, are very distant from the presumption that honorifics are markers of deference. In addition to affective meanings, I also argue that honorifics have social meanings. In other words, when speakers use honorifics, these forms communicate something about the speaker’s own identity. Someone who uses honorifics well may be perceived as educated, well-bred and even as a “good” Korean. Finally, I discuss how honorifics are tied up with gendered meanings in Korean speech and how phonetics may be playing a role.
The role of analogy in Charles Dickens’ Pictures from Italy
Authors: Wales Katie
Published: July 2017

Pictures from Italy (1846) is one of Charles Dickens’ lesser known works. There has been very little critical interest in this travelogue, and no linguistic analysis. In this chapter, I focus on the significant role of analogy in this text: broadly covering similes (like, as); quasi-similes (as if) and comparisons; and defined in cognitive terms as overt “mapping” across conceptual domains. I argue for four kinds of analogies at work, each group having different functions, effects and, most importantly, degrees of reader-helpfulness. The overall result is the creation of an Italy that is a rich composition of possible worlds and sub-worlds, corresponding as much to Dickens’ beliefs and fantasies as to actual experience. The analogies are therefore a necessary and important part of the linguistic “texture” of the work overall. They raise interesting possibilities for the further exploration of related travelogues and the discourse of tourism more generally.
The blind tour
Authors: Bernaerts Lars
Published: July 2017

On the one hand, this chapter contributes to recent efforts in narrative theory which aim at specifying the cognitive and interpretive challenge of experimental fiction. On the other hand, it focuses on the unconventional textualisation of space in narrative. Drawing on stylistics and narrative theory, it analyses spatial abstraction as an effect of stylistic features in Orchis Militaris, an experimental narrative by Ivo Michiels. The motif of blindness is prominent in the novel and will be directly linked to the reader’s processing attempts. In that respect, it echoes the analogy of blindness used by Catherine Emmott (1997) to refer to the experience of a reader who is monitoring fictional contexts. The reader of Orchis Militaris is like a blind person, but one who is not provided with sufficient clues to construct the contextual configuration of the people and settings around him or her. Particular attention will be paid to the stylistic features of spatial abstraction, the cognitive demands made on readers and the interpretive opportunities emerging from their cognitive disorientation.
“How Others See …”
Authors: Zerkowitz Judit
Published: July 2017

Miklós Radnóti’s poem “How Others See …” is often recited in Hungary as a poetic expression of patriotism, a prayer for a victimised nation. Carrying out a stylistic analysis of one translation and comparing it to two others and the original, more textual evidence was found in favour of a humanistic pacifist interpretation than the standard patriotic reading, both at the level of structural patterns and of intertextual pointers. The poem contains a pattern of contrasts between the landscape as seen by the war pilot from above and the internal landscape viewed by the poet from below. The lexical choices of the translation analysed modify attitudes to the landscape and to the war in constructing identities, and argue for only individual innocence.
Reproductive Ecology, Spawning Behavior, and Juvenile Distribution of Mountain Whitefish in the Madison River, Montana
Authors: Boyer Jan K. , Guy Christopher S. , Webb Molly A. H. , Horton Travis B. , McMahon Thomas E.
Published: July 2017

Mountain Whitefish Prosopium williamsoni were historically common throughout much of the U.S. Intermountain West. However, within the last decade Mountain Whitefish have exhibited population‐level declines in some rivers. In the Madison River, Montana, anecdotal evidence indicates Mountain Whitefish abundance has declined and the population is skewed toward larger individuals, which is typically symptomatic of recruitment problems. Describing reproductive development, spawning behavior, and juvenile distribution will form a foundation for investigating mechanisms influencing recruitment. We collected otoliths and gonadal samples from fish of all size‐classes to characterize fecundity, age at maturity, and spawning periodicity. We implanted radio tags in mature Mountain Whitefish and relocated tagged fish in autumn 2012–2014. Timing of spawning was determined from spawning status of captured females and from density of eggs collected on egg mats. In spring 2014, we seined backwater and channel sites to describe age‐0 whitefish distribution. Mountain Whitefish were highly fecund (18,454 eggs/kg body weight) annual spawners, and age at 50% maturity was 2.0 years for males and 2.6 years for females. In 2013 and 2014, spawning occurred between the third week of October and first week of November. During spawning, spawning adults and collected embryos were concentrated in the downstream 26 km of the study site, a reach characterized by a complex, braided channel. This reach had the highest CPUE of age‐0 Mountain Whitefish, and the percentage of spawning adults in the 25 km upstream from a sampling site was positively associated with juvenile CPUE. Within this reach, age‐0 Mountain Whitefish were associated with silt‐laden backwater and eddy habitats. Future investigations on mechanisms influencing recruitment should be focused on the embryological phase and age‐0 fish.

Received June 19, 2016; accepted March 28, 2017 Published online July 24, 2017
Framed Memories: The Politics of Recollection in Mana Neyestani’s An Iranian Metamorphosis
Authors: Khadem Amir
Published: July 2017

This essay examines the graphic memoir An Iranian Metamorphosis, by the acclaimed cartoonist Mana Neyestani, in the context of Iranian diaspora literature, particularly the genre of comics. Neyestani’s book is analyzed for its engagement with the politics of exile literature, and its attempt at challenging a two-dimensional view of the political discourse, in which the ethical boundaries of pro- and anti-government are overtly simple. The essay focuses on the book’s narrative techniques that exhibit a complex awareness of what is anticipated from a representative work of Iranian exile memoir, and the way it negotiates its own narrative politics. To clarify the arguments, several comparative examples are drawn from two well-known graphic narratives by Iranian diaspora authors, Marjane Satrapi’s Persepolis, and Amir and Khalil’s Zahra’s Paradise.
Evidence that Marine Temperatures Influence Growth and Maturation of Western Alaskan Chinook Salmon
Authors: Siegel Jared E. , McPhee Megan V. , Adkison Milo D.
Published: July 2017

Chinook Salmon Oncorhynchus tshawytscha from western Alaska have experienced recent declines in abundance, size, and age at maturity. Declines have led to hardships for the region's subsistence and commercial salmon harvesters, prompting calls to better understand factors affecting the life history of these populations. Western Alaskan Chinook Salmon are thought to spend their entire marine residency in the Bering Sea. The Bering Sea ecosystem demonstrates high interannual variability that is largely driven by the annual extent of sea ice. However, warming is expected to supersede interannual variability in the next several decades as a consequence of climate change. We investigated the influence of sea surface temperatures (SSTs) on the life history of western Alaskan Chinook Salmon by using information from two regional populations subject to long-term monitoring. We found strong correlations between early marine growth and SSTs. Warmer SSTs appeared to lead to a younger age at maturity, largely through the vector of augmented growth. However, we also present evidence that warmer SSTs may additionally decrease the average age of male recruits through reduced growth thresholds for early male maturation. Our results suggest that the anticipated warming of the Bering Sea will lead to higher early marine growth and a younger average age of maturation for western Alaskan Chinook Salmon.
Two populations of cytoplasmic dynein contribute to spindle
positioning in C. elegans embryos
Authors: Schmidt Ruben , Fielmich Lars-Eric , Grigoriev Ilya , Katrukha Eugene A. , Akhmanova Anna , van den Heuvel Sander
Published: July 2017

The position of the mitotic spindle is tightly controlled in animal cells as it determines the plane and orientation of cell division. Contacts between cytoplasmic dynein and astral microtubules (MTs) at the cell cortex generate pulling forces that position the spindle. An evolutionarily conserved Gα-GPR-1/2Pins/LGN–LIN-5Mud/NuMA cortical complex interacts with dynein and is required for pulling force generation, but the dynamics of this process remain unclear. In this study, by fluorescently labeling endogenous proteins in Caenorhabditis elegans embryos, we show that dynein exists in two distinct cortical populations. One population directly depends on LIN-5, whereas the other is concentrated at MT plus ends and depends on end-binding (EB) proteins. Knockout mutants lacking all EBs are viable and fertile and display normal pulling forces and spindle positioning. However, EB protein–dependent dynein plus end tracking was found to contribute to force generation in embryos with a partially perturbed dynein function, indicating the existence of two mechanisms that together create a highly robust force-generating system.
Foodservice Composting Crowds Out Consumer Food Waste Reduction Behavior in a Dining Experiment
Authors: Qi Danyi , Roe Brian E.
Published: July 2017

Many countries strive to reduce food waste, which deprives hungry people of nutrition, depletes resources, and accounts for substantial greenhouse gas emissions. Composting and other food waste recycling technologies that divert food waste from landfills mitigate the environmental damages of food waste disposal and have grown in popularity. We explore whether consumer knowledge that the environmental damage created by their food waste will be mitigated by recycling technologies undermines personal food waste reduction behavior. Subjects in a dining situation are randomly assigned whether or not they receive information about the negative effects of landfilling food waste and whether they are told that uneaten food from the study will be composted or landfilled. We find that providing information about the negative effects of food waste in landfills significantly reduces the total amount of solid food waste created when compared to a control situation that features neither a food waste reduction nor a food waste recycling policy. However, if subjects are also informed that food waste from the study will be composted, the amount of solid food waste generated is significantly greater than if only the food waste reduction policy were implemented. This suggests a crowding out effect or informational rebound effect in which promoting policies that mitigate the environmental damages of food waste may unintentionally undermine policies meant to encourage individual consumer food waste reduction. We discuss key policy implications as well as several limitations of our experimental setting and analysis.