bluuebunny/crossref_metadata_2025 huggingface dataset:
A compact, versatile low-energy electron beam ion source
Authors: Zschornack G. , König J. , Schmidt M. , Thorn A.
Published: November 2013

A new compact Electron Beam Ion Source, the Dresden EBIT-LE, is introduced as an ion source working at low electron beam energies. The EBIT-LE operates at an electron energy ranging from 100 eV to some keV and can easily be modified to an EBIT also working at higher electron beam energies of up to 15 keV. We show that, depending on the electron beam energy, electron beam currents from a few mA in the low-energy regime up to about 40 mA in the high-energy regime are possible. Technical solutions as well as first experimental results of the EBIT-LE are presented. In ion extraction experiments, a stable production of low and intermediate charged ions at electron beam energies below 2 keV is demonstrated. Furthermore, X-ray spectroscopy measurements confirm the possibility of using the machine as a source of X-rays from ions excited at low electron energies.
A comparison of geometric parameters from PBE-based doubly hybrid density functionals PBE0-DH, PBE0-2, and xDH-PBE0
Authors: Su Neil Qiang , Adamo Carlo , Xu Xin
Published: November 2013

We present a systematic investigation on the optimized geometric parameters for covalently bonded molecules, nonbonded intermolecular complexes, and transition state structures from three PBE (Perdew-Burke-Ernzerhof)-based doubly hybrid (DH) density functionals, namely PBE0-DH, PBE0-2, and xDH-PBE0. While the former two are the B2PLYP-type of DH functionals with no fit parameters, the latter is the XYG3-type of DH functional (xDH for short) with three fit parameters, whose energy expression is constructed by using density and orbital information from another standard (general) Kohn-Sham functional (i.e., PBE0) for doing the self-consistent field calculations. Generally good performances have been obtained with all three DH functionals, in particular, with xDH-PBE0.
Dynamic coupling in Cooker's sloshing experiment with baffles
Authors: Turner M. R. , Bridges T. J. , Ardakani H. Alemi
Published: November 2013

This paper investigates the dynamic coupling between fluid sloshing and the motion of the vessel containing the fluid, for the case when the vessel is partitioned using non-porous baffles. The vessel is modelled using Cooker's sloshing configuration [M. J. Cooker, “Water waves in a suspended container,” Wave Motion 20, 385–395 (1994)]. Cooker's configuration is extended to include n − 1 non-porous baffles which divide the vessel into n separate fluid compartments each with a characteristic length scale. The problem is analysed for arbitrary fill depth in each compartment, and it is found that a multitude of resonance situations can occur in the system, from 1 : 1 resonances to (n + 1)−fold 1 : 1: ⋯ : 1 resonances, as well as ℓ: m: ⋯ : n for natural numbers ℓ, m, n, depending upon the system parameter values. The conventional wisdom is that the principle role of baffles is to damp the fluid motion. Our results show that in fact without special consideration, the baffles can lead to enhancement of the fluid motion through resonance.
Reversibility of a quantum channel: General conditions and their applications to Bosonic linear channels
Authors: Shirokov M. E.
Published: November 2013

The method of complementary channel for analysis of reversibility (sufficiency) of a quantum channel with respect to families of input states (pure states for the most part) are considered and applied to Bosonic linear (quasi-free) channels, in particular, to Bosonic Gaussian channels. The obtained reversibility conditions for Bosonic linear channels have clear physical interpretation and their sufficiency is also shown by explicit construction of reversing channels. The method of complementary channel gives possibility to prove necessity of these conditions and to describe all reversed families of pure states in the Schrodinger representation. Some applications in quantum information theory are considered. Conditions for existence of discrete classical-quantum subchannels and of completely depolarizing subchannels of a Bosonic linear channel are presented.
Analyzing milestoning networks for molecular kinetics: Definitions, algorithms, and examples
Authors: Viswanath Shruthi , Kreuzer Steven M. , Cardenas Alfredo E. , Elber Ron
Published: November 2013

Network representations are becoming increasingly popular for analyzing kinetic data from techniques like Milestoning, Markov State Models, and Transition Path Theory. Mapping continuous phase space trajectories into a relatively small number of discrete states helps in visualization of the data and in dissecting complex dynamics to concrete mechanisms. However, not only are molecular networks derived from molecular dynamics simulations growing in number, they are also getting increasingly complex, owing partly to the growth in computer power that allows us to generate longer and better converged trajectories. The increased complexity of the networks makes simple interpretation and qualitative insight of the molecular systems more difficult to achieve. In this paper, we focus on various network representations of kinetic data and algorithms to identify important edges and pathways in these networks. The kinetic data can be local and partial (such as the value of rate coefficients between states) or an exact solution to kinetic equations for the entire system (such as the stationary flux between vertices). In particular, we focus on the Milestoning method that provides fluxes as the main output. We proposed Global Maximum Weight Pathways as a useful tool for analyzing molecular mechanism in Milestoning networks. A closely related definition was made in the context of Transition Path Theory. We consider three algorithms to find Global Maximum Weight Pathways: Recursive Dijkstra's, Edge-Elimination, and Edge-List Bisection. The asymptotic efficiency of the algorithms is analyzed and numerical tests on finite networks show that Edge-List Bisection and Recursive Dijkstra's algorithms are most efficient for sparse and dense networks, respectively. Pathways are illustrated for two examples: helix unfolding and membrane permeation. Finally, we illustrate that networks based on local kinetic information can lead to incorrect interpretation of molecular mechanisms.
International Fusion Materials Irradiation Facility injector acceptance tests at CEA/Saclay: 140 mA/100 keV deuteron beam characterization
Authors: Gobin R. , Bogard D. , Cara P. , Chauvin N. , Chel S. , Delferrière O. , Harrault F. , Mattei P. , Mosnier A. , Senée F. , Shidara H. , Okumura Y.
Published: November 2013

In the framework of the ITER broader approach, the International Fusion Materials Irradiation Facility (IFMIF) deuteron accelerator (2 × 125 mA at 40 MeV) is an irradiation tool dedicated to high neutron flux production for future nuclear plant material studies. During the validation phase, the Linear IFMIF Prototype Accelerator (LIPAc) machine will be tested on the Rokkasho site in Japan. This demonstrator aims to produce 125 mA/9 MeV deuteron beam. Involved in the LIPAc project for several years, specialists from CEA/Saclay designed the injector based on a SILHI type ECR source operating at 2.45 GHz and a 2 solenoid low energy beam line to produce such high intensity beam. The whole injector, equipped with its dedicated diagnostics, has been then installed and tested on the Saclay site. Before shipment from Europe to Japan, acceptance tests have been performed in November 2012 with 100 keV deuteron beam and intensity as high as 140 mA in continuous and pulsed mode. In this paper, the emittance measurements done for different duty cycles and different beam intensities will be presented as well as beam species fraction analysis. Then the reinstallation in Japan and commissioning plan on site will be reported.
Phase diagrams of Janus fluids with up-down constrained orientations
Authors: Fantoni Riccardo , Giacometti Achille , Maestre Miguel Ángel G. , Santos Andrés
Published: November 2013

A class of binary mixtures of Janus fluids formed by colloidal spheres with the hydrophobic hemispheres constrained to point either up or down are studied by means of Gibbs ensemble Monte Carlo simulations and simple analytical approximations. These fluids can be experimentally realized by the application of an external static electrical field. The gas-liquid and demixing phase transitions in five specific models with different patch-patch affinities are analyzed. It is found that a gas-liquid transition is present in all the models, even if only one of the four possible patch-patch interactions is attractive. Moreover, provided the attraction between like particles is stronger than between unlike particles, the system demixes into two subsystems with different composition at sufficiently low temperatures and high densities.
Phase separation in antisymmetric films: A molecular dynamics study
Authors: Krishnan Raishma , Jaiswal Prabhat K. , Puri Sanjay
Published: November 2013

We have used molecular dynamics (MD) simulations to study phase-separation kinetics in a binary fluid mixture (AB) confined in an antisymmetric thin film. One surface of the film (located at z = 0) attracts the A-atoms, and the other surface (located at z = D) attracts the B-atoms. We study the kinetic processes which lead to the formation of equilibrium morphologies subsequent to a deep quench below the miscibility gap. In the initial stages, one observes the formation of a layered structure, consisting of an A-rich layer followed by a B-rich layer at z = 0; and an analogous structure at z = D. This multi-layered morphology is time-dependent and propagates into the bulk, though it may break up into a laterally inhomogeneous structure at a later stage. We characterize the evolution morphologies via laterally averaged order parameter profiles; the growth laws for wetting-layer kinetics and layer-wise length scales; and the scaling properties of layer-wise correlation functions.
A portable, stable and precise laser differential refractometer
Authors: Gong Xiangjun , Ngai To , Wu Chi
Published: November 2013

In this work, we present a portable laser differential refractometer with real-time detection and high precision based on the Snell's law and a 2f-2f optical design. The 2f-2f configuration solves a traditional position drifting problem of the laser beam and enhances the signal stability, where a small pinhole is illuminated by the laser light and imaged to the detector by lens placed in the middle between the detector and the pinhole. However, it also leads to a larger dimension of the instrument, limiting its applications and its sensitivity that is proportional to the optical path. Therefore, for a portable device on the basis of the 2f-2f design, a combination of a mirror and a lens was developed to minimize the optical path without affecting the 2f-2f design. Our simple and compact design reaches a resolution of 10−6 refractive index units (RIU). Moreover, the dimension of such a modified differential refractometer is significantly reduced to be portable. Owing to its real-time detection speed and high precision, this newly developed refractometer is particularly attractive when it is used as an independent and ultra-sensitive detector in many research and industrial applications wherein there is a time-dependent concentration change, e.g., the concentration determination, quality control, and study of kinetic processes in solution, including adsorption, sedimentation, and dissolution, to name few but not limited.
Solion ion source for high-efficiency, high-throughput solar cell manufacturing
Authors: Koo John (Bon-Woong) , Binns Brant , Miller Timothy , Krause Stephen , Skinner Wesley , Mullin James
Published: November 2013

In this paper, we introduce the Solion ion source for high-throughput solar cell doping. As the source power is increased to enable higher throughput, negative effects degrade the lifetime of the plasma chamber and the extraction electrodes. In order to improve efficiency, we have explored a wide range of electron energies and determined the conditions which best suit production. To extend the lifetime of the source we have developed an in situ cleaning method using only existing hardware. With these combinations, source life-times of >200 h for phosphorous and >100 h for boron ion beams have been achieved while maintaining 1100 cell-per-hour production.
Future carbon beams at SPIRAL1 facility: Which method is the most efficient?
Authors: Maunoury L. , Delahaye P. , Angot J. , Dubois M. , Dupuis M. , Frigot R. , Grinyer J. , Jardin P. , Leboucher C. , Lamy T.
Published: November 2013

Compared to in-flight facilities, Isotope Separator On-Line ones can in principle produce significantly higher radioactive ion beam intensities. On the other hand, they have to cope with delays for the release and ionization which make the production of short-lived isotopes ion beams of reactive and refractory elements particularly difficult. Many efforts are focused on extending the capabilities of ISOL facilities to those challenging beams. In this context, the development of carbon beams is triggering interest [H. Frånberg, M. Ammann, H. W. Gäggeler, and U. Köster, Rev. Sci. Instrum. 77, 03A708 (2006); M. Kronberger, A. Gottberg, T. M. Mendonca, J. P. Ramos, C. Seiffert, P. Suominen, and T. Stora, in Proceedings of the EMIS 2012 [Nucl. Instrum. Methods Phys. Res. B Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source (to be published)]: despite its refractory nature, radioactive carbon beams can be produced from molecules (CO or CO2), which can subsequently be broken up and multi-ionized to the required charge state in charge breeders or ECR sources. This contribution will present results of experiments conducted at LPSC with the Phoenix charge breeder and at GANIL with the Nanogan ECR ion source for the ionization of carbon beams in the frame of the ENSAR and EMILIE projects. Carbon is to date the lightest condensable element charge bred with an ECR ion source. Charge breeding efficiencies will be compared with those obtained using Nanogan ECRIS and charge breeding times will be presented as well.
How to induce multiple delays in coupled chaotic oscillators?
Authors: Bhowmick Sourav K. , Ghosh Dibakar , Roy Prodyot K. , Kurths Jürgen , Dana Syamal K.
Published: November 2013

Lag synchronization is a basic phenomenon in mismatched coupled systems, delay coupled systems, and time-delayed systems. It is characterized by a lag configuration that identifies a unique time shift between all pairs of similar state variables of the coupled systems. In this report, an attempt is made how to induce multiple lag configurations in coupled systems when different pairs of state variables attain different time shift. A design of coupling is presented to realize this multiple lag synchronization. Numerical illustration is given using examples of the Rössler system and the slow-fast Hindmarsh-Rose neuron model. The multiple lag scenario is physically realized in an electronic circuit of two Sprott systems.
On the role of electron energy distribution function in double frequency heating of electron cyclotron resonance ion source plasmas
Authors: Schachter L. , Stiebing K. E. , Dobrescu S.
Published: November 2013

Double frequency heating (DFH) is a tool to improve the output of highly charged ions particularly from modern electron cyclotron resonance ion source installations with very high RF-frequencies. In order to gain information on the DFH-mechanism and on the role of the lower injected frequency we have carried out a series of dedicated experiments where we have put emphasis on the creation of a discrete resonance surface also for this lower frequency. Our well-established method of inserting an emissive MD (metal-dielectric) liner into the plasma chamber of the source is used in these experiments as a tool of investigation. In this way, the electron temperature and density for both ECR zones is increased in a controlled manner, allowing conclusions on the role of the change of the electron-energy-distribution function with and without DFH.
Production of fullerene ions by combining of plasma sputtering with laser ablation
Authors: Yamada K. , Saitoh Y. , Yokota W.
Published: November 2013

We have produced C60 ion beams by combining plasma sputtering and laser ablation. A C60 sample was placed in an electron cyclotron resonance type ion source, negatively biased and sputtered by argon plasma. The beam current of C60+ decreased rapidly, but it was transiently recovered by a single laser shot that ablates the thin sample surface on the sputtered area. Temporal variations in beam current are reported in response to laser shots repeated at intervals of a few minutes.
High-k shallow traps observed by charge pumping with varying discharging times
Authors: Ho Szu-Han , Chang Ting-Chang , Lu Ying-Hsin , Wang Bin-Wei , Lo Wen-Hung , Chen Ching-En , Tsai Jyun-Yu , Chen Hua-Mao , Liu Kuan-Ju , Tseng Tseung-Yuen , Cheng Osbert , Huang Cheng-Tung , Chen Tsai-Fu , Cao Xi-Xin
Published: November 2013

In this paper, we investigate the influence of falling time and base level time on high-k bulk shallow traps measured by charge pumping technique in n-channel metal-oxide-semiconductor field-effect transistors with HfO2/metal gate stacks. NT-Vhigh level characteristic curves with different duty ratios indicate that the electron detrapping time dominates the value of NT for extra contribution of Icp traps. NT is the number of traps, and Icp is charge pumping current. By fitting discharge formula at different temperatures, the results show that extra contribution of Icp traps at high voltage are in fact high-k bulk shallow traps. This is also verified through a comparison of different interlayer thicknesses and different TixN1−x metal gate concentrations. Next, NT-Vhigh level characteristic curves with different falling times (tfalling time) and base level times (tbase level) show that extra contribution of Icp traps decrease with an increase in tfalling time. By fitting discharge formula for different tfalling time, the results show that electrons trapped in high-k bulk shallow traps first discharge to the channel and then to source and drain during tfalling time. This current cannot be measured by the charge pumping technique. Subsequent measurements of NT by charge pumping technique at tbase level reveal a remainder of electrons trapped in high-k bulk shallow traps.
Improved value for the silicon free exciton binding energy
Authors: Green Martin A.
Published: November 2013

The free exciton binding energy is a key parameter in silicon material and device physics. In particular, it provides the necessary link between the energy threshold for valence to conduction band optical absorption and the bandgap determining electronic properties. The long accepted low temperature binding energy value of 14.7 ± 0.4 meV is reassessed taking advantage of developments subsequent to its original determination, leading to the conclusion that this value is definitely an underestimate. Using three largely independent experimental data sets, an improved low temperature value of 15.01 ± 0.06 meV is deduced, in good agreement with the most comprehensive theoretical calculations to date.
Large thermopower in the antiferromagnetic semiconductor BaMn2Bi2
Authors: Wang Kefeng , Petrovic C.
Published: November 2013

We report electrical and thermal transport properties of Mn-based material BaMn2Bi2 with ThCr2Si2 structure. The resistivity of the antiferromagnetic BaMn2Bi2 shows a metal-semiconductor transition at ∼80 K with decreasing temperature. Correspondingly, the thermopower S shows a peak at the same temperature, approaching 150 μV/K. With increasing temperature, S decreases to about 125 μV/K at the room temperature. The magnetic field enhances the peak value to 210 μV/K. The Hall resistivity reveals an abrupt change of the carrier density close to the metal-semiconductor transition temperature.
Growth and properties of crystalline barium oxide on the GaAs(100) substrate
Authors: Yasir M. , Dahl J. , Kuzmin M. , Lång J. , Tuominen M. , Punkkinen M. P. J. , Laukkanen P. , Kokko K. , Korpijärvi V.-M. , Polojärvi V. , Guina M.
Published: November 2013

Growing a crystalline oxide film on III-V semiconductor renders possible approaches to improve operation of electronics and optoelectronics heterostructures such as oxide/semiconductor junctions for transistors and window layers for solar cells. We demonstrate the growth of crystalline barium oxide (BaO) on GaAs(100) at low temperatures, even down to room temperature. Photoluminescence (PL) measurements reveal that the amount of interface defects is reduced for BaO/GaAs, compared to Al2O3/GaAs, suggesting that BaO is a useful buffer layer to passivate the surface of the III-V device material. PL and photoemission data show that the produced junction tolerates the post heating around 600 °C.
Gigawatt peak power generation in a relativistic klystron amplifier driven by 1 kW seed-power
Authors: Wu Y. , Xie H. Q. , Li Z. H. , Zhang Y. J. , Ma Q. S.
Published: November 2013

An S-band high gain relativistic klystron amplifier driven by kW-level RF power is proposed and studied experimentally. In the device, the RF lossy material is introduced to suppress higher mode excitation. An output power of 1.95 GW with a gain of 62.8 dB is obtained in the simulation. Under conditions of an input RF power of 1.38 kW, a microwave pulse with power of 1.9 GW, frequency of 2.86 GHz, and duration of 105 ns is generated in the experiment, and the corresponding gain is 61.4 dB.
Volume contribution of exchange-coupling-induced uniaxial anisotropy in Fe/CoO/MgO(001) system
Authors: Zhu J. , Li Q. , Li J. X. , Ding Z. , Won C. Y. , Wu Y. Z.
Published: November 2013

An unusual volume contribution of exchange-coupling-induced uniaxial anisotropy in a single-crystalline Fe/CoO/MgO(001) system was discovered and measured using the magneto-optical Kerr effect. The observed volume contribution emerges with the establishment of CoO antiferromagnetic order below the CoO blocking temperature or above a critical CoO thickness. It decays with decreasing exchange coupling strength tuned by inserting a MgO layer between the Fe and CoO layers. The volume anisotropy of the Fe layer is attributed to the strain transferred from the CoO layer induced by the magnetostriction effect through a field cooling process. Our results indicate that the strain in antiferromagnetic film can be applied to control the exchange coupling effect in the future spintronics devices.
Effects of Co layer thickness and annealing temperature on the magnetic properties of inverted [Pt/Co] multilayers
Authors: Lee Tae Young , Chan Won Young , Su Son Dong , Ho Lim Sang , Lee Seong-Rae
Published: November 2013

The effects of Co layer thickness and annealing temperature on the perpendicular magnetic anisotropy (PMA) properties of inverted [Pt (0.2 nm)/Co (tCo)]6 multilayers (where tCo indicates the thickness of the Co layer) have been investigated. The cross-sectional microstructure, as observed from the high-resolution transmission electron microscope images, shows a clear layered structure with atomically flat interfaces both in the as-deposited state as well as after annealing, indicating the interface effects for PMA. The effective PMA energy density (Keff) increases significantly with an increase in tCo from 0.2 to 0.28 nm and then becomes almost saturated with further increases in tCo, followed by a slight reduction at the highest Co thickness, tCo = 0.6 nm. In order to explain the tCo dependence on Keff, the intrinsic PMA energy density (Ki) is calculated by additionally measuring a similar set of results for the saturation magnetization. The Ki value increases nearly linearly with the increase in tCo from 0.2 to 0.5 nm, followed by saturation at a higher tCo value of 0.6 nm. Owing to a close relationship between Ki and the quality of the interfaces, these results indicate a similar tCo dependence on the quality of the interfaces. This is further supported from the magnetic measurements of the samples annealed at the highest temperature of 500 °C, where a second phase is formed, which show a similar tCo dependence on the amount of the second phase. The Ki value is nearly independent of the annealing temperature at tCo ≤ 0.4 nm, above which a substantial reduction is observed, when the annealing temperature exceeds 500 °C.
Two-dimensional excitons in three-dimensional hexagonal boron nitride
Authors: Cao X. K. , Clubine B. , Edgar J. H. , Lin J. Y. , Jiang H. X.
Published: November 2013

The recombination processes of excitons in hexagonal boron nitride (hBN) have been probed using time-resolved photoluminescence. It was found that the theory for two-dimensional (2D) exciton recombination describes well the exciton dynamics in three-dimensional hBN. The exciton Bohr radius and binding energy deduced from the temperature dependent exciton recombination lifetime is around 8 Å and 740 meV, respectively. The effective masses of electrons and holes in 2D hBN deduced from the generalized relativistic dispersion relation of 2D systems are 0.54mo, which are remarkably consistent with the exciton reduced mass deduced from the experimental data. Our results illustrate that hBN represents an ideal platform to study the 2D optical properties as well as the relativistic properties of particles in a condensed matter system.
Dielectric breakdown properties of hot SF6/He mixtures predicted from basic data
Authors: Wang Weizong , Tu Xin , Mei Danhua , Rong Mingzhe
Published: November 2013

Sulfur hexafluoride (SF6) gas has a quite high global warming potential and hence it is required that applying any substitute for SF6 gas. Much interest in the use of a mixture of helium and SF6 as arc quenching medium was investigated indicating a higher recovery performance of arc interruption than that of pure SF6. It is known that the electrical breakdown in a circuit breaker after arc interruption occurs in a hot gas environment, with a complicated species composition because of the occurrence of dissociation and other reactions. The likelihood of breakdown relies on the electron interactions with all these species. The critical reduced electric field strength (the field at which breakdown can occur, relative to the number density) of hot SF6/He mixtures related to the dielectric recovery phase of a high voltage circuit breaker is calculated in the temperature range from 300 K to 3500 K. The critically reduced electric field strength of these mixtures was obtained by balancing electron generation and loss mechanisms. These were evaluated using the electron energy distribution function derived from the Boltzmann transport equation under the two-term approximation. Good agreement was found between calculations for pure hot SF6 and pure hot He and experimental results and previous calculations. The addition of He to SF6 was found to decrease the critical reduced electric field strength in the whole temperature range due to a lack of electron impact attachment process for helium regardless its high ionization potential. This indicates that not the behaviour of dielectric strength but possibly the higher energy dissipation capability caused mainly by light mass and high specific heat as well as thermal conductivity of atomic helium contributes most to a higher dielectric recovery performance of arc interruption for SF6/He mixtures.
The influence of dual-carrier recombination and release on electrical characteristics of pentacene-based ambipolar transistors
Authors: Chiu Liang-Yun , Cheng Horng-Long , Chou Wei-Yang , Tang Fu-Ching
Published: November 2013

Electrical characteristics of pentacene-based ambipolar organic field-effect transistors (OFETs) are examined and are shown to significantly differ from those of unipolar OFETs. The electrical and hysteresis characteristics of the ambipolar OFETs depend on the applied source-drain bias and sweeping gate voltage range. The ambipolar OFET characteristics, such as charge mobility, subthreshold swing, threshold voltage, and off-current level, are controlled by the dual-carrier recombination and release process, through which opposite-sign charges can capture and release majority charges. This study contributes to advancing the development of more applications based on ambipolar OFETs.
The interface inter-diffusion induced enhancement of the charge-trapping capability in HfO2/Al2O3 multilayered memory devices
Authors: Lan Xuexin , Ou Xin , Lei Yan , Gong Changjie , Yin Qiaonan , Xu Bo , Xia Yidong , Yin Jiang , Liu Zhiguo
Published: November 2013

An effective method to generate traps at the interface was developed to enhance the charge trapping capability of HfO2/Al2O3 multilayered memory devices. A high charge density was obtained in the inter-diffusion layer in which additional trap sites could be created by thermal-treatment induced inter-diffusion. By keeping the consistent thickness of the charge trapping layer and increasing the number of the inter-diffusion layers, more traps can be introduced in the charge trapping layer. So, creating more trap sites by enhancing the inter-diffusion at the interface of different high-k dielectrics could be a potential choice for future memory applications.
Effect of injected spins with different polarized orientations on the superconductivity of La0.7Sr0.3MnO3/La1.85Sr0.15CuO4 thin films
Authors: Zhang M. J. , Yin Y. W. , Su T. S. , Teng M. L. , Zhang D. L. , Li X. G. , Zou L. J.
Published: November 2013

The influence of spin-polarized quasi-particle injection on the superconductivity of epitaxial La0.7Sr0.3MnO3/La1.85Sr0.15CuO4 composite thin films is systematically investigated. Different electrode configurations on the same specimen are designed to study the role of spin injection. It is found that the upper critical field and flux pinning potential are reduced by the spin injection, especially for the field parallel to ab-plane. The manipulation of superconductivity by the spin polarization orientations of injected quasi-particles possibly originates from the different suppressions on the superconducting pairing strength, which is considered to be related to the local antiferromagnetic spin fluctuations in La1.85Sr0.15CuO4.
Fatigue-free unipolar strain behavior in CaZrO3 and MnO2 co-modified (K,Na)NbO3-based lead-free piezoceramics
Authors: Yao Fang-Zhou , Glaum Julia , Wang Ke , Jo Wook , Rödel Jürgen , Li Jing-Feng
Published: November 2013

The unipolar fatigue behavior of CaZrO3 and MnO2 co-modified (K,Na,Li)(Nb,Ta)O3 lead-free piezoceramics was investigated systematically. The well-known charge agglomeration model is shown to explain the overall changes observed during unipolar fatigue, such as the development of bias field as well as the anisotropy in bipolar strain hysteresis and field-dependent dielectric permittivity. In addition, it is found that the unipolar strain exhibits only small degradation within 3% at the field amplitude of 2 kV/mm up to 107 cycles. This exceptionally good fatigue resistance is identified due to the presence of additional process, assigned as a “softening” effect that competes against the usual fatigue effect.
A ferroelectric polarization contribution from defect dipoles in acceptor Aurivillius oxide, (Na,Bi)0.47(Li,Ce)0.03Bi2Ta1.97Sc0.03O8.97
Authors: Long Changbai , Fan Huiqing , Li Mengmeng
Published: November 2013

Double-loop-like characteristic was detected in acceptor Aurivillius ceramic, (Na,Bi)0.47(Li,Ce)0.03Bi2Ta1.97Sc0.03O8.97 (NBTO-LiCeSc-0.03) due to the restoring force provided by defect polarization (PD). The PD was associated with non-centric distributing defect dipoles [(ScTa″-VO••)×], which was verified by impedance spectroscopy measures. Interestingly, the PD could be reoriented with high external electric field at very low frequency, which contributed to the significant enhancement of the polarization of NBTO-LiCeSc-0.03. Air or O2 annealing led to the degradation of the polarization owing to high leakage current and the strong “pinning” effects of space charge and charged defect complexes [e.g., (ScTa″-OO•)′].
Optical diode based on exciton-polaritons
Authors: Espinosa-Ortega T. , Liew T. C. H. , Shelykh I. A.
Published: November 2013

We propose theoretically an optical diode based on exciton-polaritons in semiconductor microcavities. A flow of polaritons in the bistable regime is used to send signals through an asymmetric fixed potential that favours the bridging of particles in one direction. Through dynamic modelling of the coherent polariton field, we demonstrate the characteristics of an ideal diode, namely, that the forward signal is fully transmitted while the transmission in the reverse direction tends to zero, without any additional external control. Moreover, the system proves to be robust to the presence of disorder, intrinsic to microcavities, and can function at gigahertz repetition rates.
Effect of non-diffusive processes on transport and its interpretation in the tokamak plasma edge
Authors: Stacey Weston M.
Published: November 2013

An interpretive methodology improved to account for two non-diffusive transport mechanisms—particle pinch and ion orbit loss—was applied to interpret the difference in transport (i) between a discharge with Resonance Magnetic Perturbations and a High confinement mode discharge with otherwise identical operating parameters and (ii) between the Low confinement and High confinement phases of a discharge free of Edge Localized Modes. Differences in particle and energy diffusion coefficients and in the particle pinch were inferred from the experimental data, and the inferred experiment thermal diffusion coefficients were compared with various theoretical predictions. The effect of taking ion orbit loss into account in the interpretation was quantified, and the possible relation of ion orbit loss to the observed transport “edge shortfall” is discussed.
Remote sensor response study in the regime of the microwave radiation-induced magnetoresistance oscillations
Authors: Ye Tianyu , Mani R. G. , Wegscheider W.
Published: November 2013

A concurrent remote sensing and magneto-transport study of the microwave excited two dimensional electron system (2DES) at liquid helium temperatures has been carried out using a carbon detector to remotely sense the microwave activity of the 2D electron system in the GaAs/AlGaAs heterostructure during conventional magneto-transport measurements. Various correlations are observed and reported between the oscillatory magnetotransport and the remotely sensed reflection. In addition, the oscillatory remotely sensed signal is shown to exhibit a power law type variation in its amplitude, similar to the radiation-induced magnetoresistance oscillations.
Anisotropy of the crossover between electrostatic attraction and repulsion of biological cells
Authors: Murovec T. , Brosseau C.
Published: November 2013

By applying an ac electric field to a pair of layered concentric shells, a prototypical model of biological cells, we demonstrate that the sign and magnitude of the time averaged electrostatic force (EF) are strongly dependent on the field frequency. Crossover frequencies (CFs) occur when EFs vanish. Unique physical features of CF bands are studied as function of field frequency and gap distance between cells. The distance between cells corresponding to the CF shows both anisotropic and universal features. The ability to control the long-range EFs and CFs opens up exciting prospective applications including the deposition of biological cells under field excitation in an architecture that could create functional tissue.
Optical tuning of dielectric properties of Ba0.6Sr0.4TiO3-La(Mg0.5Ti0.5)O3 ceramics in the terahertz range
Authors: Wu Liang , Jiang Linkun , Xu Yebin , Ding Xin , Yao Jianquan
Published: November 2013

The dielectric properties of 0.4Ba0.6Sr0.4TiO3-0.6La(Mg0.5Ti0.5)O3 ceramics and their tunability under external optical fields are investigated at room temperature by means of terahertz time-domain spectroscopy. Application of the optical field leads to an appreciable tuning of the permittivity, which reaches up to 16%. Meanwhile, the dielectric loss changes about 21%. From the results, we find that the change of refractive index has a linear relationship on scale with the applied light power. These findings are attributed to the internal space charge field in the ceramic caused by the excited free carriers.
Microfluidics-enabled method to identify modes of Caenorhabditis elegans paralysis in four anthelmintics
Authors: Lycke Roy , Parashar Archana , Pandey Santosh
Published: November 2013

The discovery of new drugs is often propelled by the increasing resistance of parasites to existing drugs and the availability of better technology platforms. The area of microfluidics has provided devices for faster screening of compounds, controlled sampling/sorting of whole animals, and automated behavioral pattern recognition. In most microfluidic devices, drug effects on small animals (e.g., Caenorhabditis elegans) are quantified by an end-point, dose response curve representing a single parameter (such as worm velocity or stroke frequency). Here, we present a multi-parameter extraction method to characterize modes of paralysis in C. elegans over an extended time period. A microfluidic device with real-time imaging is used to expose C. elegans to four anthelmintic drugs (i.e., pyrantel, levamisole, tribendimidine, and methyridine). We quantified worm behavior with parameters such as curls per second, types of paralyzation, mode frequency, and number/duration of active/immobilization periods. Each drug was chosen at EC75 where 75% of the worm population is responsive to the drug. At equipotent concentrations, we observed differences in the manner with which worms paralyzed in drug environments. Our study highlights the need for assaying drug effects on small animal models with multiple parameters quantified at regular time points over an extended period to adequately capture the resistance and adaptability in chemical environments.
Retention of Gap Length in Normal-Hearing Listeners
Authors: Ries Dennis T , Woods Audra , Smith Meghan
Published: November 2013

Listener retention of silent, gap-length duration was studied. Just noticeable differences (JNDs) for gap length within standard and comparison stimuli were obtained for intervals with and without intervening noise bursts, including a condition with gapped intervening bursts. Outcomes indicate that gap duration itself can be determinant. Also, JNDs were similar whether intervening stimuli were present or absent, differing from results reported for pitch, loudness, and timbre retention. The latter suggests additional/alternative cortical resources might be employed for retention of auditory–temporal information.
Using Acoustic Information to Perceive Room Size: Effects of Blindness, Room Reverberation Time, and Stimulus
Authors: Kolarik Andrew J , Pardhan Shahina , Cirstea Silvia , Moore Brian C J
Published: November 2013

Blind participants greatly rely on sound for spatial information regarding the surrounding environment. It is not yet established whether lack of vision to calibrate audition in far space affects blind participants' internal spatial representation of acoustic room size. Furthermore, blind participants may rely more on farthest distance estimates to sound sources compared with sighted participants when perceiving room size. Here we show that judgments of apparent room size and sound distance are correlated, more so for blind than for sighted participants. Sighted participants judged a reverberant virtual room to be larger for speech than for music or noise stimuli, whereas blind participants did not. The results suggest that blindness affects the use of room reverberation for distance and room-size judgments.
Structure, Thermal Behaviour, and Energetic Properties of 4-Amino-1,2,4-triazole Dinitroguanidine Salt
Authors: Jin Xinghui , Hu Bingcheng , Jia Huanqing , Liu Zuliang , Lu Chunxu
Published: November 2013

A novel nitrogen-rich energetic compound 4-amino-1,2,4-triazole dinitroguanidine salt (4-ATDNG) was synthesized and fully characterized. Its crystal, thermal behaviour, and detonation properties were investigated by X-ray diffraction, thermogravimetry-derivative thermogravimetry-differential scanning calorimetry (TG-DTG-DSC) coupling system, and the Kamlet–Jacobs equation. In view of the obtained values such as the critical temperature of thermal explosion (Tb, 186.36°C), entropy of activation (ΔS≠, 60.22 J mol–1 k–1), enthalpy of activation (ΔH≠, 143.24 kJ mol–1), free energy of activation (ΔG≠, 116.34 kJ mol–1), detonation pressure (P, 29.78 GPa), detonation velocity (V, 8.28 km s–1), and impact sensitivity (h50 = 135 cm), it is proposed that 4-ATDNG possesses excellent thermal stability and has the potential to be a useful energetic material in the future.
Field-scale variability of soil test phosphorus and other nutrients in grasslands under long-term agricultural managements
Authors: Fu Weijun , Zhao Keli , Jiang Peikun , Ye Zhengqian , Tunney Hubert , Zhang Chaosheng
Published: November 2013

Field-scale variation of soil nutrients in grassland is becoming important because of the use of soil-nutrient information as a basis for policies such as the recently introduced EU Nitrates Directive. This study investigates the field-scale variability of soil-test phosphorus (STP) and other nutrients in two grasslands with a long-term history of poultry litter application. Two fields (field 1 for silage and field 2 for grazing pasture) were selected, and soil samples were collected based on 12 m by 12 m (field 1) and 15 m by 15 m (field 2) grids. Data were analysed using conventional statistics, geostatistics, and a geographic information system (GIS). In field 1, STP values ranged from 12.4 to 90 mg L–1 (average 38.5 mg L–1). In field 2, STP values ranged from 4.3 to 130.0 mg L–1 (average 21.4 mg L–1). Attention should be paid to long-term poultry application, as the average STP values in both fields were much greater than the recommended agronomic optimum STP status in Ireland of 8 mg L–1. Coefficient of variation values of soil nutrients in field 2 were much higher than those in field 1. Log-transformation and Box–Cox transformation were applied to achieve normality. Statistically significant (P < 0.01), positive correlations between P and other nutrients were found in both fields. Exponential and spherical models were fitted to the experimental variograms of STP in fields 1 and 2, respectively. Compared with the counterparts in field 1, soil nutrients in field 2 had larger ‘nugget-to-sill’ values, revealing that sheep grazing could weaken the spatial auto-correlation of soil nutrients. A grid of 60 m by 60 m was recommended for soil sampling in grassland, based on this study. High STP concentrations in field 1 were in the north-eastern side, which was related to uneven poultry litter application. Strong spatial similarity of low STP, magnesium, and pH values in their spatial distribution were found in field 2, confirming their strong statistical correlation.
Abundance and composition of ammonia-oxidising bacteria and archaea of a degraded lake wetland, Inner Mongolian Plateau, China
Authors: Wu Linhui , Hui Lihua , Wang Xiaoyi , Li Jingyu , Yu Jingli , Zhao Ji
Published: November 2013

Wetlands are one of the most highly threatened ecosystems on Earth, and their loss and degradation are regarded as major environmental problems. The degradation rate of lake wetlands of the Huitengxile grassland, Inner Mongolia, has increased over recent years. In this study, soil samples were collected in a degraded lake wetland of the Huitengxile grassland. The abundance and composition of soil ammonia-oxidising bacteria (AOB) and ammonia-oxidising archaea (AOA) were assessed by quantitative real-time PCR, cloning, and sequencing approaches. Four sampling sites were selected according to the order of water withdrawal. The lakeshore sample appeared to have the highest copy numbers of AOB amoA genes, and the lowest AOB population size was found in the lakebed sample. Similar to AOB, the AOA were most abundant in the lakeshore sample, and the population size in the lake centre sample was the lowest. Ex2cept in one lakebed sample, AOB were more abundant than AOA in all other samples, with AOB to AOA ratios ranging from 11 to 13. Phylogenetic analysis of the amoA gene fragments showed that all AOB sequences from different sites were affiliated to class β-Proteobacteria, order Nitrosomonadales, family Nitrosomonadaceae and can be grouped into two clusters. Little difference was found in AOB community composition among different samples, which indicated that AOB community composition was stable during the drying process of the degraded lake. However, the AOA community compositions were very different between samples. All AOA sequences fell into four clusters. Cluster 1 was dominant in the sample from the centre of the lake, and cluster 2 was dominant in the lakeshore sample, indicating a difference in the community composition of AOA in response to the drying up of the lake. No clear relationship was found between the AOA and AOB community populations and soil physio-chemical properties. This study suggested that the AOA community in wetland systems is more sensitive than the AOB community to the drying process of the wetland ecosystem.
X-linked microtubule-associated protein, Mid1, regulates axon development
Authors: Lu Tingjia , Chen Renchao , Cox Timothy C. , Moldrich Randal X. , Kurniawan Nyoman , Tan Guohe , Perry Jo K. , Ashworth Alan , Bartlett Perry F. , Xu Li , Zhang Jing , Lu Bin , Wu Mingyue , Shen Qi , Liu Yuanyuan , Richards Linda J. , Xiong Zhiqi
Published: November 2013

Significance

The gene responsible for the X-linked form of Opitz syndrome (OS),
Midline-1
(
MID1
), encodes an E3 ubiquitin ligase and was reported to guide the degradation of the catalytic subunit of protein phosphatase 2A (PP2Ac). But whether and how it is involved in neural development is unclear. We demonstrate here that Mid1-dependent PP2Ac turnover is involved in axon development. Knocking down or knocking out Mid1 not only promotes axon growth and branching in vitro, but also accelerates axon elongation and disrupts the pattern of callosal projection in mouse cortex. These defects can be reversed by down-regulating the accumulated PP2Ac in Mid1-depleted cells. Dysfunction of this Mid1–PP2Ac pathway may underlie neural symptoms of OS patients.
The SUMO proteases SENP1 and SENP2 play a critical role in nucleoporin homeostasis and nuclear pore complex function
Authors: Chow Kin-Hoe , Elgort Suzanne , Dasso Mary , Powers Maureen A. , Ullman Katharine S.
Published: November 2013

Nuclear pore complexes are composed of ∼30 different proteins, each present at the pore in multiple copies. Together these proteins create specialized channels that convey cargo between the cytoplasm and the nuclear interior. With the building blocks of nuclear pores identified, one challenge is to decipher how these proteins are coordinately produced and assembled into macromolecular pore structures with each cell division. Specific individual pore proteins and protein cofactors have been probed for their role in the assembly process, as well as certain kinases that add a layer of regulation via the phosphorylation status of nucleoporins. Other posttranslational modifications are candidates for coordinating events of pore assembly as well. In this study of two pore-associated small ubiquitin-like modifier (SUMO) proteases, sentrin/SUMO-specific protease 1 (SENP1) and SENP2, we observe that many nucleoporins are mislocalized and, in some cases, reduced in level when SENP1 and SENP2 are codepleted. The pore complexes present under these conditions are still capable of transport, although the kinetics of specific cargo is altered. These results reveal a new role for the pore-associated SENPs in nucleoporin homeostasis and in achieving proper configuration of the nuclear pore complex.