bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of a nanodroplet under a transmission electron microscope
Authors: Leong Fong Yew , Mirsaidov Utkur M. , Matsudaira Paul , Mahadevan L.
Published: January 2014

We investigate the cyclical stick-slip motion of water nanodroplets on a hydrophilic substrate viewed with and stimulated by a transmission electron microscope. Using a continuum long wave theory, we show how the electrostatic stress imposed by non-uniform charge distribution causes a pinned convex drop to deform into a toroidal shape, with the shape characterized by the competition between the electrostatic stress and the surface tension of the drop, as well as the charge density distribution which follows a Poisson equation. A horizontal gradient in the charge density creates a lateral driving force, which when sufficiently large, overcomes the pinning induced by surface heterogeneities in the substrate disjoining pressure, causing the drop to slide on the substrate via a cyclical stick-slip motion. Our model predicts step-like dynamics in drop displacement and surface area jumps, qualitatively consistent with experimental observations.
Noncontact determination of thin films conductance by SH plate acoustic waves
Authors: Kuznetsova I. E. , Zaitsev B. D. , Anisimkin V. I. , Teplykh A. A. , Shikhabudinov A. M. , Kolesov V. V. , Yakunin V. G.
Published: January 2014

The paper is devoted to the development of noncontact acoustic method of the determination of thin film conductance by using shear-horizontal zero order (SH0) acoustic waves in thin piezoelectric plates. The method is based on the registration of changes in velocity and attenuation of acoustic waves in a piezoelectric plate due to placing the structure “film under study–dielectric substrate” on the certain distance from the plate. The limits of measured values by the suggested method are determined. The theoretical data are compared with the experimental results.
Pressure induced ionic-superionic transition in silver iodide at ambient temperature
Authors: Han Y. H. , Wang H. B. , Troyan I. A. , Gao C. X. , Eremets M. I.
Published: January 2014

Silver iodide (AgI-V) is an archetypical ionic compound for studying the formation mechanism of a superionic state. Previous studies have proven that superionic AgI with high ionic conductivity greater than 0.1 Ω−1cm−1 could only be obtained at high temperatures. We show in this paper that high pressure could also induce the superionic state in AgI even at ambient temperature. Using electrochemical impedance spectroscopy, we investigated Ag+ ions diffusing in rock-salt structured AgI-III and KOH-type AgI-V under high pressures and directly observed the superionic state in AgI-V. The diffusion coefficient of AgI-V is ∼3.4 × 10−4-8.6 × 10−4 cm2/s in the investigated pressure range of 12-17 GPa, comparable with those of superionic α-AgI and AgI-III′. By analyzing the half infinite length Warburg diffusion process, two parameters α and β, which closely relate to the disordered state of Ag+ ions, have been determined and it was suggested that Ag+ ions in AgI-V become disordered. The ionic conductivity of AgI-V is three orders of magnitude higher than that of AgI-III, and has reached around 0.1 Ω−1cm−1. Evidence for all three, the diffusion coefficient, α and β, and conductivity have proven that AgI-V is a superionic conductor at ambient temperature.
Nonuniform magnetic stresses in high temperature superconducting thin films
Authors: Zhang Xingyi , Liu Cong , Zhou Jun , Zhou Youhe
Published: January 2014

We provide an experimental measurement of the magnetic stresses in high temperature superconducting thin films based on the Coherent Gradient Sensor which has many merits such as real time, non-destructive, full field, vibration insensitivity, etc. As an example, the radial stress, hoop stress of the YBa2Cu3O7-x (YBCO) film, and shear stress between the film and the (00l) SrTiO3 substrate subjected to various magnetic fields at 40 K are obtained. For the interfacial shear stress in radial direction between the film and substrate, it is found that the magnitude order of which is at GPa at somewhere under a small magnetic field.
Evolution and effects of surface degradation layer of Sm2Co17 magnets at high temperatures
Authors: Mao Shoudong , Yan Minsheng , Nie Xia , Sun Keqing , Jiang Jianjun , Song Zhenlun
Published: January 2014

The long-term application of SmCo-based magnets at high temperatures has been restricted by the irreversible loss of magnetic properties. In this work, degradation behavior of Sm2Co17 magnets was studied at 500 °C in air and vacuum by being focused on the surface degradation layer. The structure and the composition of the degradation layer were studied experimentally, and the magnetization was calculated to certify the deduction of the irreversible loss. The soft magnetic phases in the degradation layer can result in the decline of the magnetization and the irreversible loss of magnetic properties. Furthermore, the controversial formation reason of the degradation layer was also studied. It was found that the diffusion of the oxygen, but not the sublimation of Sm, could be the dominant formation reason of the degradation layers.
Energy harvesting from ambient low-frequency magnetic field using magneto-mechano-electric composite cantilever
Authors: Liu Guoxi , Ci Penghong , Dong Shuxiang
Published: January 2014

A magneto-mechano-electric (MME) composite cantilever for energy harvesting from ambient low-frequency magnetic field has been investigated in this study. The MME composite cantilever is made of a piezoelectric bimorph with NdFeB magnets attached at its tip. The properties of the MME composite cantilever based energy harvester were theoretically predicted by using the equivalent circuit model. The experimental results show that the maximum power density for excitations at the short- and open-circuit resonance frequencies (<100 Hz) is 11.73 μW/Oe2 cm3, which is one order of magnitude higher than that of previously reported magnetoelectric energy harvester. The research has proved the potential application of the composite cantilever for harvesting ambient low-frequency magnetic field energy.
Communication: Overcoming the root search problem in complex quantum trajectory calculations
Authors: Zamstein Noa , Tannor David J.
Published: January 2014

Three new developments are presented regarding the semiclassical coherent state propagator. First, we present a conceptually different derivation of Huber and Heller's method for identifying complex root trajectories and their equations of motion [D. Huber and E. J. Heller, J. Chem. Phys. 87, 5302 (1987)]. Our method proceeds directly from the time-dependent Schrödinger equation and therefore allows various generalizations of the formalism. Second, we obtain an analytic expression for the semiclassical coherent state propagator. We show that the prefactor can be expressed in a form that requires solving significantly fewer equations of motion than in alternative expressions. Third, the semiclassical coherent state propagator is used to formulate a final value representation of the time-dependent wavefunction that avoids the root search, eliminates problems with caustics and automatically includes interference. We present numerical results for the 1D Morse oscillator showing that the method may become an attractive alternative to existing semiclassical approaches.
Note: Charge transfer in a hydrated peptide group is determined mainly by its intrinsic hydrogen-bond energetics
Authors: Mirkin Noemi G. , Krimm Samuel
Published: January 2014

Charge transfer in a hydrogen-bonded N-methylacetamide(H2O)3 system is obtained from ωB97X-D/6-31++G** and CHelpG atomic charge calculations of individual peptide-water interactions as well as that of the entire complex. In the latter, the electron transfer to water is 0.19 e, influenced primarily by the hydrogen bonds to the C=O group. The values of such charge transfer are paralleled by the corresponding intrinsic hydrogen-bond energies. These results support the desirability of incorporating charge transfer in molecular mechanics energy functions.
Optimum surface condition for plasmonic Ag nanoparticles in polycrystalline silicon thin film solar cells
Authors: Park Jongsung , Park Nochang , Varlamov Sergey
Published: January 2014

Excitation of surface plasmons in silver nanoparticles is a promising method for increasing the light absorption in solar cells and hence, the cell photocurrent. The optical environment is an important key factor to consider when designing plasmonic solar cells because it affects the surface plasmon characteristics. In this paper, we applied the silver nanoparticles on the rear side of polycrystalline silicon thin film solar cells and systematically investigated the optimum surface condition for maximising plasmonic enhanced light absorption in the cells. Three different environments, thermal silicon dioxide (SiO2), native SiO2, and oxide-free silicon surface were investigated. We found that the existence of the SiO2 layer between Si and nanoparticles has a major effect on Qscat and therefore, the absorption in the cells. We also found that nanoparticles on the thermal SiO2 layer showed that the peak of Qscat is located at the visible light wavelengths <700 nm, nanoparticles on the native SiO2 layer and directly on Si sample showed that their peaks of Qscat are positioned at the longer wavelengths >700 nm. The sample with nanoparticles on the native SiO2 layer showed the highest potential short circuit current density (Jsc) enhancement, 62.5%, and absolute Jsc enhancement, 32.3%. On the other hand, the sample with nanoparticles on the thermal SiO2 layer indicated 19.6% enhancement of Jsc.
Sapphire decomposition and inversion domains in N-polar aluminum nitride
Authors: Hussey Lindsay , White Ryan M. , Kirste Ronny , Mita Seiji , Bryan Isaac , Guo Wei , Osterman Katherine , Haidet Brian , Bryan Zachary , Bobea Milena , Collazo Ramón , Sitar Zlatko
Published: January 2014

Transmission electron microscopy (TEM) techniques and potassium hydroxide (KOH) etching confirmed that inversion domains in the N-polar AlN grown on c-plane sapphire were due to the decomposition of sapphire in the presence of hydrogen. The inversion domains were found to correspond to voids at the AlN and sapphire interface, and transmission electron microscopy results showed a V-shaped, columnar inversion domain with staggered domain boundary sidewalls. Voids were also observed in the simultaneously grown Al-polar AlN, however no inversion domains were present. The polarity of AlN grown above the decomposed regions of the sapphire substrate was confirmed to be Al-polar by KOH etching and TEM.
Ordering recombinant silk-elastin-like nanofibers on the microscale
Authors: Zeng Like , Teng Weibing , Jiang Linan , Cappello Joseph , Wu Xiaoyi
Published: January 2014

Self-assembled peptide/polypeptide nanofibers are appealing building blocks for creating complex three-dimensional structures. However, ordering assembled peptide/polypeptide nanofibers into three-dimensional structures on the microscale remains challenging and often requires the employment of top-down approaches. We report that silk-elastin-like protein polymers self-assemble into nanofibers in physiologically relevant conditions, the assembled nanofibers further form fiber clusters on the microscale, and the nanofiber clusters eventually coalesce into three-dimensional structures with distinct nanoscale and microscale features. It is believed that the interplay between fiber growth and molecular diffusion leads to the ordering of the assembled silk-elastin-like nanofibers at the microscale.
Current induced perpendicular-magnetic-anisotropy racetrack memory with magnetic field assistance
Authors: Zhang Y. , Zhao W. S. , Klein J.-O. , Chappert C. , Ravelosona D.
Published: January 2014

High current density is indispensable to shift domain walls (DWs) in magnetic nanowires, which limits the using of racetrack memory (RM) for low power and high density purposes. In this paper, we present perpendicular-magnetic-anisotropy (PMA) Co/Ni RM with global magnetic field assistance, which lowers the current density for DW motion. By using a compact model of PMA RM and 40 nm design kit, we perform mixed simulation to validate the functionality of this structure and analyze its density potential. Stochastic DW motion behavior has been taken into account and statistical Monte-Carlo simulations are carried out to evaluate its reliability performance.
Self-purification construction of interstitial O in the neighbor of Eu3+ ions to act as energy transfer bridge
Authors: Yang Lei , Dong Jiazhang , She Yajuan , Jiang Zhongcheng , Zhang Lide , Yu Hongbin
Published: January 2014

We develop a strategy to investigate bridge role of O-related defects in the neighbor of Eu3+ in energy transfer (ET). By solvothermal reactions and following annealing process, Eu3+ doped ZnO nanocrystal is synthesized. After low-temperature annealing, Eu3+ ions occupy substituted sites of ZnO. High temperature annealing results in self-purification process—the separation of Eu3+ ions from ZnO lattice and generation of Eu2O3 precipitate phases. However, in this case, the proportion of individual Eu2O3 particles is extremely low if they are separated. The precipitate phases have paralleled edges and parallel to (011¯1¯) plane of ZnO. By self-purification separation, these O-terminated planes are easy to couple with Eu3+ ions, and form Eu3+ trap state. In order to maintain hexa-coordinate of Eu3+ ions, many O-related vacancies and interstitial defects are generated in the interface of ZnO/Eu2O3, among which interstitial O (Oi) in the neighbor of Eu3+ ions plays an important role in balance charge and ET. Thus, it is not strange to observe enhanced luminescence peak in self-purified samples.
Resonant spin and valley polarization in ferromagnetic silicene quantum well
Authors: Wang Yu
Published: January 2014

We propose a silicene-based lateral resonant tunneling device by placing silicene under the modulation of top nonmagnetic/ferromagnetic/nonmagnetic sandwich nanogates. Following the electric-tunable bandgap of silicene, lateral double-barrier structure is formed by imposing the flexible electrostatic modulation on top gates. By aligning the spin and valley-resolved confined states in magnetic well, remarkable spin/valley polarization can be accessed through spinor-relying resonant tunneling mechanism. Under the electrostatic, magnetic, and size manipulation, the confined well state can be efficiently engineered, and the observed spin and valley polarization can be further flexibly tuned, offering some helpful strategies to construct spinor-electronic logic atomically.
Thermoelectric properties in the series Ti1-xTaxS2
Authors: Beaumale M. , Barbier T. , Bréard Y. , Hébert S. , Kinemuchi Y. , Guilmeau E.
Published: January 2014

Polycrystalline samples in the series Ti1-xTaxS2 with x varying from 0 to 1 were prepared using solid-liquid-vapor reaction and spark plasma sintering. Rietveld refinements of X-ray diffraction data are consistent with the existence of a full solid solution for x ≤ 0.4. Transport measurements reveal that tantalum can act as electron donor when substituted in the Ti sites. As a consequence, the electrical resistivity and the absolute value of the Seebeck coefficient decrease with Ta content due to an increase in the carrier concentration. The lattice thermal conductivity being reduced due to mass fluctuation effect, the ZT values in Ti0.95Ta0.05S2 is slightly increased as compared to TiS2.
Ferroelectric control of in-plane to out-of-plane magnetization switching at poly(vinylidene fluoride)/iron interface
Authors: Wang Rui-Qi , Zhu Wan-Jiao , Ding Hang-Chen , Gong Shi-Jing , Duan Chun-Gang
Published: January 2014

Using relativistic density-functional theory calculations, we investigate magnetocrystalline anisotropy energy (MAE) of the poly(vinylidene fluoride)(PVDF)/Fe/Cu/Ag heterostructure. We find that MAE of this heterostructure can be flexibly manipulated by the ferroelectric polarization of PVDF. In particular, by carefully designing the interface structure, we demonstrate that the ferroelectric polarization reversal can switch the easy axis of the Fe layer from in-plane to out-of-plane, due to the surface/interface magnetoelectric effect. We expect such strategy would be beneficial to electric-field controlled magnetic data storage.
Enhanced x-ray emissions from Au-Gd mixture targets ablated by a high-power nanosecond laser
Authors: Dong Yunsong , Shang Wanli , Yang Jiamin , Zhang Lu , Zhang Wenhai , Li Zhichao , Guo Liang , Zhan Xiayu , Du Huabing , Deng Bo , Pu Yikang
Published: January 2014

As an important x-ray source, enhancement of x-ray emissions from laser-produced plasmas is imperative for various applications. High-Z Au-Gd mixture targets are proposed to enhance the laser to x-ray conversion efficiency compared to pure Au target. In the experiments, a 1 ns frequency-tripled (351 nm wavelength) laser light was used to obtain an intensity of 3×1014 W/cm2 on the targets. The x-ray spectra, total absolute x-ray emissions of all space, M-band fraction and backscattering from pure Au and Au-Gd mixture have been measured, respectively. It is shown that the absolute laser to x-ray conversion efficiency for the Au-Gd mixture containing 60% gold by atom is 47.7%, which has a 15% enhancement compared with that of the pure Au target. The experimental results are consistent with the radiation hydrodynamic simulations.
Anisotropic manipulation of ferroelectric polarization in SrTiO3/(Co0.9Zn0.1)Fe2O4 heterostructural films by magnetic field
Authors: Chen Bo , Li Yong-Chao , Wang Jun-Yong , Wan Jian-Guo , Liu Jun-Ming
Published: January 2014

Multiferroic SrTiO3/(Co0.9Zn0.1)Fe2O4 (STO/CZFO) films with preferential crystallographic orientations were prepared by a sol-gel process. The films exhibited evident ferroelectricity and well-defined ferromagnetic characteristics with certain magnetic anisotropy. Remarkable suppression of ferroelectric polarization by in-plane magnetic field and great enhancement under out-of-plane magnetic field were realized, and large anisotropic magnetodielectric effect was observed. We showed that the ferroelectric polarization of the whole film was closely related to the defect dipoles in the STO layer. Based on the model where the dissociation or formation of defect dipoles is associated with the volume change of STO unit cells, we elucidated the mechanism of anisotropic magnetic-manipulation of ferroelectric polarization for the films, and attributed it to the rearrangement of oxygen vacancies in the STO layer, which was controlled by the ferromagnetic CZFO layer through interface coupling under external magnetic field.
Unusual magnetic hysteresis and the weakened transition behavior induced by Sn substitution in Mn3SbN
Authors: Sun Ying , Guo Yanfeng , Tsujimoto Yoshihiro , Wang Cong , Li Jun , Wang Xia , Feng Hai L. , Sathish Clastin I. , Matsushita Yoshitaka , Yamaura Kazunari
Published: January 2014

Substitution of Sb with Sn was achieved in ferrimagnetic antiperovskite Mn3SbN. The experimental results indicate that with an increase in Sn concentration, the magnetization continuously decreases and the crystal structure of Mn3Sb1-xSnxN changes from tetragonal to cubic phase at around x of 0.8. In the doping series, step-like anomaly in the isothermal magnetization was found and this behavior was highlighted at x = 0.4. The anomaly could be attributed to the magnetic frustration, resulting from competition between the multiple spin configurations in the antiperovskite lattice. Meantime, Hc of 18 kOe was observed at x = 0.3, which is probably the highest among those of manganese antiperovskite materials reported so far. With increasing Sn content, the abrupt change of resistivity and the sharp peak of heat capacity in Mn3SbN were gradually weakened. The crystal structure refinements indicate the weakened change at the magnetic transition is close related to the change of c/a ratio variation from tetragonal to cubic with Sn content. The results derived from this study indicate that the behavior of Mn3Sb1-xSnxN could potentially enhance its scientific and technical applications, such as spin torque transfer and hard magnets.
Electronic structure calculations of PbS quantum rods and tubes
Authors: Pimachev Artem , Dahnovsky Yuri
Published: January 2014

We study absorption spectra, optical and HOMO-LUMO gaps, and the density of states for PbS quantum rods (QRs) and tubes (QTs). We find some similarities and also differences in QR and QT properties. For both QRs and QTs, the optical and HOMO-LUMO gaps reach the plateaus for small lengths. We find that tubes are as stable as rods. The optical spectra exhibit a peak that can be due to the electron-hole interaction or be a prototype of an Se–Sh transition in the effective mass approximation. We also calculate the density of states by the density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The TDDFT density of states function is shifted towards the red side by 0.5 eV indicating the strong e-h interaction.
First-principles study of the effect of phosphorus on nickel grain boundary
Authors: Liu Wenguan , Ren Cuilan , Han Han , Tan Jie , Zou Yang , Zhou Xingtai , Huai Ping , Xu Hongjie
Published: January 2014

Based on first-principles quantum-mechanical calculations, the impurity-dopant effects of phosphorus on Σ5(012) symmetrical tilt grain boundary in nickel have been studied. The calculated binding energy suggests that phosphorus has a strong tendency to segregate to the grain boundary. Phosphorus forms strong and covalent-like bonding with nickel, which is beneficial to the grain boundary cohesion. However, a too high phosphorus content can result in a thin and fragile zone in the grain boundary, due to the repulsion between phosphorus atoms. As the concentration of phosphorus increases, the strength of the grain boundary increases first and then decreases. Obviously, there exists an optimum concentration for phosphorus segregation, which is consistent with observed segregation behaviors of phosphorus in the grain boundary of nickel. This work is very helpful to understand the comprehensive effects of phosphorus.
Investigation on transition behavior and electrical properties of (K0.5Na0.5)1-xLixNb0.84Ta0.1Sb0.06O3 around polymorphic phase transition region
Authors: Zhu Chen , Wang Wenchao , Huang Jiquan , Tang Fei , Liu Yang , Shi Honglin , Wang Fangyu , Wang Chong , Cao Yongge , Yuan Xuanyi
Published: January 2014

(K0.5Na0.5)1-xLixNb0.84Ta0.1Sb0.06O3 (KNLNTS) lead free ceramics with different Li concentration were fabricated by conventional solid-state reaction method. By increasing Li ions in KNLNTS, the grains grow up and the crystal structure changes from orthorhombic to tetragonal. When 0.03 ≤ x ≤ 0.05, the ceramics structure lays in PPT region. Polarization versus electric field (P-E) hysteresis loops at room temperature show good ferroelectric properties and the remnant polarization decreases by increasing Li content while coercive electric keeps almost unchanged. In PPT region, taking x = 0.04 as an example, the sample shows excellent dielectric properties: the dielectric constant is 1159 and loss tangent is 0.04, while the piezoelectric constant d33 is 245 pC/N and kp is 0.44 at room temperature, it is promising for (K0.5Na0.5)1-xLixNb0.84Ta0.1Sb0.06O3 with 4 at. % Li to substitute PZT.
Stable organic field-effect-transistors with high mobilities unaffected by supporting dielectric based on phenylene-bridged thienobenzothiophene
Authors: Mathis T. , Liu Y. , Ai L. , Ge Z. , Lumpi D. , Horkel E. , Holzer B. , Froehlich J. , Batlogg B.
Published: January 2014

We report on the electrical properties of organic field-effect transistors (OFET) based on a new class of organic semiconductors. The molecules consist of the same thieno[2,3-b][1]benzothiophene building blocks, connected by different π-bridge spacers (ethylene, phenylene, and fluorophenylene). Molecular orbitals and highest occupied molecular orbital/lowest unoccupied molecular orbital energies were calculated and compared with results from cyclic voltammetric and UV-vis absorption measurements. In order to study the influence of the bridge groups on the molecular arrangement and surface interaction, the transistor performance on a wide range of dielectrics has been investigated in detail. These include as grown SiO2 and Al2O3 and also treated with octadecyltrichrolosilane and octadecylphosphonic acid, as well as Cytop and Parylene C. An extended study of the multitude of combinations of these materials revealed mobilities up to ∼1 cm2/Vs, measured for devices made of the phenylene-bridged compound. Surprisingly, the mobility was quite independent of the supporting gate dielectric. Stability over time has been observed with no degradation after 5 months. By eliminating the hysteresis using Cytop, we were able to show that some of the molecules form films without long-term charge carrier trapping. These are interesting features for practical industrial processing of organic electronics.
Structural, electronic, and optical properties of GaInO3: A hybrid density functional study
Authors: Wang V. , Xiao W. , Ma D.-M. , Liu R.-J. , Yang C.-M.
Published: January 2014

The structural, electronic, and optical properties of GaInO3 have been studied by first-principles calculations based on Heyd-Scuseria-Ernzerhof hybrid functional theory. The optical properties, including the optical reflectivity, refractive index, extinction coefficient, absorption coefficient, and electron energy loss are discussed for radiation up to 60 eV together with the calculated electronic structure. Our results predicted that GaInO3 displays good transparency over the whole vision region, which is in good agreement with the experimental data available in the literature.
Effects of neutron irradiation of ultra-thin HfO2 films
Authors: Hsu K.-W. , Ren H. , Agasie R. J. , Bian S. , Nishi Y. , Shohet J. L.
Published: January 2014

Neutron irradiation at low fluence decreases the Pb-type and E′ defect levels in ultra-thin hafnium dioxide films because electrons can fill existing states. These electrons come from electron-hole pairs generated by neutron interactions with silicon and oxygen. Thus, a low fluence of neutrons “anneals” the sample. However, when neutron fluence increases, more neutrons collide with oxygen atoms and cause them to leave the lattice or to transmute into different atoms. This causes the E′ states to increase. As defect-state concentrations increase, leakage currents increase, but since the E′ is much lower than the Pb concentration, this is not a dominant factor.
Relaxation of vacancy depth profiles in silicon wafers: A low apparent diffusivity of vacancy species
Authors: Voronkov V. V. , Falster R. , Pichler P.
Published: January 2014

Vacancy depth profiles in silicon wafers—installed by Rapid Thermal Annealing and monitored by Pt diffusion—show, upon subsequent annealing at 975 or 950 °C, a peculiar evolution: the concentration profile goes down without any trace of vacancy out-diffusion. The estimated apparent diffusivity is less than 10−7 cm2/s at 975 °C. The monitored vacancy species is tentatively identified as a “slow vacancy” that was recently concluded to exist along with other (highly mobile) vacancy species.
Dual-band polarization angle independent 90° polarization rotator using twisted electric-field-coupled resonators
Authors: Shi Hongyu , Zhang Anxue , Zheng Shi , Li Jianxing , Jiang Yansheng
Published: January 2014

A bilayered chiral metamaterial is proposed to realize a dual band polarization angle insensitive 90° polarization rotator. The unit cell of the chiral metamaterial is composed by twisted electric field coupled resonators in four-fold rotation symmetry. The simulation and measured results show that this device can work in dual band with an extremely low loss and polarization conversion ratio of more than 99%. The study of the current and electric fields distribution indicates that the cross-polarization transmission is due to both the electric coupling and the magnetic coupling.
Room-temperature vibrational properties of multiferroic MnWO4 under quasi-hydrostatic compression up to 39 GPa
Authors: Ruiz-Fuertes J. , Errandonea D. , Gomis O. , Friedrich A. , Manjón F. J.
Published: January 2014

The multiferroic manganese tungstate (MnWO4) has been studied by high-pressure Raman spectroscopy at room temperature under quasi-hydrostatic conditions up to 39.3 GPa. The low-pressure wolframite phase undergoes a phase transition at 25.7 GPa, a pressure around 8 GPa higher than that found in previous works, which used less hydrostatic pressure-transmitting media. The pressure dependence of the Raman active modes of both the low- and high-pressure phases is reported and discussed comparing with the results available in the literature for MnWO4 and related wolframites. A gradual pressure-induced phase transition from the low- to the high-pressure phase is suggested on the basis of the linear intensity decrease of the Raman mode with the lowest frequency up to the end of the phase transition.
Equation of state of rhenium and application for ultra high pressure calibration
Authors: Anzellini Simone , Dewaele Agnès , Occelli Florent , Loubeyre Paul , Mezouar Mohamed
Published: January 2014

The isothermal equation of state of rhenium has been measured by powder X-ray diffraction experiments up to 144 GPa at room temperature in a diamond anvil cell. A helium pressure transmitting medium was used to minimize the non-hydrostatic stress on the sample. The fit of pressure-volume data yields a bulk modulus K0 = 352.6 GPa and a pressure derivative of the bulk modulus K′0=4.56. This equation of state differs significantly from a recent determination [Dubrovinsky et al., Nat. Commun. 3, 1163 (2012)], giving here a lower pressure at a given volume. The possibility of using rhenium gasket X-ray diffraction signal, with the present equation of state, to evaluate multi-Mbar pressures in the chamber of diamond anvil cells is discussed.
Investigation of orthorhombic-to-tetragonal structural phase transition in (Ba1−xCax)(Zr0.05Ti0.95)O3 ferroelectric ceramics using micro-Raman scattering
Authors: Singh Gurvinderjit , Sathe Vasant , Tiwari V. S.
Published: January 2014

Ferroelectric phase transition from orthorhombic-to-tetragonal phase was investigated in (Ba1−xCax)(Zr0.05Ti0.95)O3 ceramics [x = 0.05, 0.08, 0.10] by micro-Raman scattering. The room temperature Raman scattering reveals the presence of orthorhombic-tetragonal phase co-existence by emergence of tetragonal phase with increase in calcium content. The temperature dependent Raman spectra also show similar cross-over with hardening of A(TO2) mode and disappearance of A(LO1) mode as system moves from orthorhombic-to-tetragonal phase. A thermal hysteresis of ∼10 K was observed in orthorhombic-to-tetragonal transition.
Enhancement of exchange bias and training effect in ion-beam sputtered Fe46Mn54/Ni81Fe19 bilayers
Authors: Fulara Himanshu , Chaudhary Sujeet , Kashyap Subhash C. , Granville Simon
Published: January 2014

We present a remarkable enhancement by 300% of the exchange-bias field at room temperature, without affecting the coercivity value, via optimum magnetic annealing (250 °C/3 kOe) in ion-beam sputtered FeMn(30 nm)/NiFe(10 nm) bilayers. This specific behavior has been attributed to a higher degree of γ-FeMn(111) orientation that offers more interfacial FeMn moments to get pinned with the moments of the adjacent NiFe layer. Unlike the absence of training effect at room temperature, a pronounced training effect and an accompanying magnetization reversal asymmetry are evidenced upon field cooling below 50 K due to the presence of biaxial exchange induced anisotropy across the interdiffused FeMn/NiFe interface. The present findings not only have technological significance but also are of relevance to the understanding of interfacial spin disorder and frustration in these exchange-biased systems.
Gamma ray irradiated silicon nanowires: An effective model to investigate defects at the interface of Si/SiOx
Authors: Yin Kui , Zhao Yi , Wang Xiaoliang , Liu Liangbin , Xue Gi , Lee Shuit-Tong , Shao Mingwang
Published: January 2014

The effect of gamma ray irradiation on silicon nanowires was investigated. Here, an additional defect emerged in the gamma-ray-irradiated silicon nanowires and was confirmed with electron spin resonance spectra. 29Si nuclear magnetic resonance spectroscopy showed that irradiation doses had influence on the Q4 unit structure. This phenomenon indicated that the unique core/shell structure of silicon nanowires might contribute to induce metastable defects under gamma ray irradiation, which served as a satisfactory model to investigate defects at the interface of Si/SiOx.
Band-gap engineering in fluorographene nanoribbons under uniaxial strain
Authors: Zhang Yan , Li Qunxiang
Published: January 2014

Based on extensive first-principles calculations, we report the structural and electronic properties of fluorinated graphene, i.e., fluorographene nanoribbons (FGNRs) under uniaxial strain. Our results indicate that the FGNRs are semiconductors with wide direct band gaps regardless of their edge structures. Moreover, the band gap of FGNR can be effectively modulated nonlinearly with the applied uniaxial elastic strain, where the band gap value increases first and then reduces when the applied strain changes from −10.0% to 10.0%. This abnormal behavior mainly originates from the electronic structures of valence and conduction band edges, which is quite different from previously reported linear behavior on graphene nanoribbon. Our results imply the great potential applications of FGNRs in the optical electronics.
Ab initio prediction of SiC nanotubes with negative strain energy
Authors: Alfieri G. , Kimoto T.
Published: January 2014

Single-layer SiC nanotubes (SiCNTs) are known to be metastable structures that is why only nanotubular fibers or polygrained nanotubes have been obtained experimentally. In this study, we report on how hydrogen helps to overcome the metastability of SiCNTs. Starting from SiC graphitic sheets, we analyzed the impact of either partial or full hydrogenation on the electronic properties and structural stability of SiCNTs. It is shown that, in general, hydrogenation widens the band gap of both SiC graphitic sheets and nanotubes and, irrespective of the difference in chirality and diameter, leads to the formation of energetically stable SiCNTs.
Do We Need Another Neural Correlate of Contour Integration?
Authors: de-Wit Lee , Schwarzkopf Dietrich Samuel
Published: January 2014

Gilad and colleagues use an elegant combination of voltage-sensitive dyes and high temporal and spatial resolution optical imaging to visualize a differential response to collinear contour elements in monkey V1. This result adds to the literature on the neural correlates of contour integration, but does not yet tackle (or seek to tackle) the question as to whether contour integration is mediated by lateral connections within an area (e.g., V1), through pooling of feedfoward connections, or feedback mechanisms. Moreover, while Gilad et al. find that their differential response is correlated with the behavioral performance of each monkey, there are reasons to suspect that the correlation they observe is a consequence of processing in higher regions, and that the differential V1 response may not play a critical role in integrating contour elements, or in generating the monkey's response. Moreover, this differential V1 response was not observed in a monkey who was not trained on the task, a result that can only be reconciled, if one assumes that the monkey could not see the contour prior to training. If valid, this could raise doubts as to whether the study of contour integration really provides insights into the processes by which normal visual perception is achieved.
Identifying and mapping cell-type-specific chromatin programming of gene expression
Authors: Marstrand Troels T. , Storey John D.
Published: January 2014

Significance

In order for genes to be expressed in humans, the DNA corresponding to a gene and its regulatory elements must be accessible. It is hypothesized that this accessibility and its effect on gene expression plays a major role in defining the different cell types that make up a human. We have only recently been able to make the measurements necessary to model DNA accessibility and gene-expression variation in multiple human cell types at the genome-wide level. We develop and apply a new quantitative framework for identifying locations in the human genome whose DNA accessibility drives cell-type-specific gene expression.
RNA design rules from a massive open laboratory
Authors: Lee Jeehyung , Kladwang Wipapat , Lee Minjae , Cantu Daniel , Azizyan Martin , Kim Hanjoo , Limpaecher Alex , Gaikwad Snehal , Yoon Sungroh , Treuille Adrien , Das Rhiju ,   EteRNA Participants
Published: January 2014

Significance

Self-assembling RNA molecules play critical roles throughout biology and bioengineering. To accelerate progress in RNA design, we present EteRNA, the first internet-scale citizen science “game” scored by high-throughput experiments. A community of 37,000 nonexperts leveraged continuous remote laboratory feedback to learn new design rules that substantially improve the experimental accuracy of RNA structure designs. These rules, distilled by machine learning into a new automated algorithm EteRNABot, also significantly outperform prior algorithms in a gauntlet of independent tests. These results show that an online community can carry out large-scale experiments, hypothesis generation, and algorithm design to create practical advances in empirical science.
Tumor-specific IL-9–producing CD8+Tc9 cells are superior effector than type-I cytotoxic Tc1 cells for adoptive immunotherapy of cancers
Authors: Lu Yong , Hong Bangxing , Li Haiyan , Zheng Yuhuan , Zhang Mingjun , Wang Siqing , Qian Jianfei , Yi Qing
Published: January 2014

Significance

Our laboratory has identified a critical role of IL-9 in promoting endogenous tumor-specific cytotoxic T lymphocyte response. In this study, we found that differentiation of CD8+T cells under T helper 9-polarizing conditions induces the development of an IL-9–producing less cytolytic IL-9–skewed CD8+T (Tc9) cell subset. Noticeably, adoptive transfer of tumor-reactive Tc9 cells elicited greater antitumor responses against large established tumors than classic type-I CD8+cytotoxic T cells that are used in clinical protocols. Importantly, Tc9 cells have substantially enhanced persistence potential and possess the capacity to acquire/maintain effector function after transfer. Our results also revealed that Tc9-mediated therapeutic effect critically depended on IL-9 production in vivo. The ability of Tc9 cells to confer sustained antitumor responses might open an avenue for the advances of cancer immunotherapy.
Identification and characterization of the constituent human serum antibodies elicited by vaccination
Authors: Lavinder Jason J. , Wine Yariv , Giesecke Claudia , Ippolito Gregory C. , Horton Andrew P. , Lungu Oana I. , Hoi Kam Hon , DeKosky Brandon J. , Murrin Ellen M. , Wirth Megan M. , Ellington Andrew D. , Dörner Thomas , Marcotte Edward M. , Boutz Daniel R. , Georgiou George
Published: January 2014

Significance

Most vaccines confer immunity by eliciting long-term production of antibodies that bind to and neutralize the vaccine antigen. Remarkably, very little is known regarding the identities, sequence diversity, relative concentrations, or binding functionalities of the mAbs that comprise the serum repertoire elicited by vaccination. Here, we have delineated the constituent antibodies of the human serum IgG repertoire after vaccination and examined their relationship to the antibody V gene repertoire encoded by circulating B cells. The results detail the molecular composition and characteristics of the vaccine-specific serum antibody repertoire and demonstrate differences between the end-point response (the serum antibodies) and the peripheral B cells responding to the vaccine.
Separating endogenous ancient DNA from modern day contamination in a Siberian Neandertal
Authors: Skoglund Pontus , Northoff Bernd H. , Shunkov Michael V. , Derevianko Anatoli P. , Pääbo Svante , Krause Johannes , Jakobsson Mattias
Published: January 2014

Significance

Strict laboratory precautions against present day human DNA contamination are standard in ancient DNA studies, but contamination is already present inside many ancient human fossils from previous handling without specific precautions. We designed a statistical framework to isolate endogenous ancient DNA sequences from contaminating sequences using postmortem degradation patterns and were able to reduce high-contamination fractions to negligible levels. We captured DNA sequences from a contaminated Neandertal bone from Okladnikov Cave in Siberia and used our method to assemble its mitochondrial genome sequence, which we find to be from a lineage basal to five of six previously published complete Neandertal mitochondrial genomes. Our method paves the way for the large-scale genetic analysis of contaminated human remains.
Anomalous diffusion and multifractality enhance mating encounters in the ocean
Authors: Seuront Laurent , Stanley H. Eugene
Published: January 2014

Significance

In the ocean, chemoreception plays a crucial role in increasing mate encounter rates in millimeter-scale crustaceans through pheromone trails that can be followed over hundreds of body lengths. Empirical evidence of trail following behavior is, however, limited to laboratory experiments conducted in still water. An important open question concerns what happens in the turbulent waters of the surface ocean where crustaceans instead experience background pheromone concentration. We show that both males and females of two key species react to background pheromone concentration, and their emerging behaviors depend on pheromone concentration, sex, species, and the level of reproductive experience of the individual tested, and are consistent with an adaptation to increase mate encounter rates.
Nanowire nanocomputer as a finite-state machine
Authors: Yao Jun , Yan Hao , Das Shamik , Klemic James F. , Ellenbogen James C. , Lieber Charles M.
Published: January 2014

Significance

Fundamental limits soon may end the decades-long trend in microelectronic computer circuit miniaturization that has led to much technological and economic progress. Nanoelectronic circuits using new materials, devices, and/or fabrication methods face formidable challenges to provide alternatives for future microelectronics. A key advance toward overcoming these hurdles is achieved in this work through the construction of a nanoelectronic finite-state machine (nanoFSM) computer using “bottom–up” methods. The nanoFSM integrates both computing and memory elements, which are organized from individually addressable and functionally identical nanodevices, to perform clocked, multistage logic. Furthermore, the device density is the highest reported to date for any nanoelectronic system. Advances in logic and design in the nanoFSM are scalable and should enable more extensive nanocomputers.
The Texture of Discourse
Authors: Renkema Jan
Published: January 2014

The aim of this monograph is to give impetus to research into one of the central questions in discourse studies: what makes a sequence of sentences or utterances a discourse?

The theoretical framework for describing the possibilities of discourse continuation is delineated by two principles: the discursive and the dialogic principle. The ‘chord’ of discourse is unfolded in a tripartite ‘wire’: Conjunction, Adjunction and Interjunction, each containing three aspects, leading to a Connectivity Model. This new three-by-three taxonomy of discourse relations incorporates findings from several theories and approaches that have evolved over the last three decades, including Systemic Functional Linguistics and Rhetorical Structure Theory. In comparing this model to other models, this book presents a state-of-the-art of discourse relation analysis combined with detailed accounts of many examples. This monograph furthermore proposes a new way of presenting discourse structures—in ‘connectivity graphs’—followed by eleven commandments for the segmentation and labeling of discourse, and three procedures for disambiguation if more labels are applicable. This study can provide a base for corpus linguistic analysis on discourse structures, computational approaches to discourse generation and cognitive experimental research of discourse competence.
English Prepositions Explained
Authors: Lindstromberg Seth
Published: January 2014

This completely revised and expanded edition of English Prepositions Explained (EPE), originally published in 1998, covers approximately 100 simple, compound, and phrasal English prepositions of space and time – with the focus being on short prepositions such as at, by, in, and on. Its target readership includes teachers of ESOL, pre-service translators and interpreters, undergraduates in English linguistics programs, studious advanced learners and users of English, and anyone who is inquisitive about the English language. The overall aim is to explain how and why meaning changes when one preposition is swapped for another in the same context. While retaining most of the structure of the original, this edition says more about more prepositions. It includes many more figures – virtually all new. The exposition draws on recent research, and is substantially founded on evidence from digitalized corpora, including frequency data. EPE gives information and insights that will not be found in dictionaries and grammar handbooks.
Introduction to Healthcare for Interpreters and Translators
Authors: Crezee Ineke H.M.
Published: January 2014

“Getting information off the internet is like taking a drink from a fire hydrant.” (Mitchell Kapor, n.d.). Medical concepts and terminology can be very confusing for the uninitiated interpreter or translator. This book will allow interpreters and translators to quickly read up on healthcare settings, familiarizing themselves with anatomy, physiology, medical terminology and frequently encountered conditions, investigations and treatment options. Health translators working on medical reports will be able to find commonly used abbreviations. Those who have been asked to translate health information material into community languages will be able to gain a good basic overview of related background information and crosscultural issues. Those who teach health interpreters or translators will find this book helpful for structuring their curriculum. Information is presented in a consistent, logical and informative manner, intended to support, rather than overwhelm.

Crezee was appointed an Officer of the New Zealand Order of Merit for services to interpreter and translator education in the 2020 New Year Honours list.
New Perspectives on English as a European Lingua Franca
Authors: Motschenbacher Heiko
Published: January 2014

This volume complements earlier work on English as a lingua franca (ELF) by providing an in-depth study of the phenomenon from a decidedly European perspective. Distancing itself from more traditional approaches to the study of English in Europe (linguistic imperialism and “Euro-English”), the study is theoretically grounded in more recent approaches, namely the ELF paradigm and the postmodernist conceptualisation of “English”. Methodologically speaking, the study analyses language use in Eurovision Song Contest press conferences as a community of practice of European salience. The ethnographically based analyses focus on various linguistic levels, thereby producing a comprehensive picture of European ELF as a discursive formation. Various qualitative and quantitative methods are used to shed light on the following aspects: code-choice practices in ELF talk, participants’ metalinguistic comments on the use of ELF, complimenting behaviour via ELF and relativisation patterns. On the basis of this data, the concluding section advances discussions revolving around the conceptualisation of ELF in general, the connection between ELF and Europeanness, and implications for European language policies.