bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of injection beam emittance on beam transmission efficiency in a cyclotron
Authors: Kurashima Satoshi , Kashiwagi Hirotsugu , Miyawaki Nobumasa , Yoshida Ken-Ichi , Okumura Susumu
Published: December 2013

The JAEA AVF cyclotron accelerates various kinds of high-energy ion beams for research in biotechnology and materials science. Beam intensities of an ion species of the order of 10−9–10−6 ampere are often required for various experiments performed sequentially over a day. To provide ion beams with sufficient intensity and stability, an operator has to retune an ion source in a short time. However, the beam intensity downstream of the cyclotron rarely increases in proportion to the intensity at the ion source. To understand the cause of this beam behavior, transmission efficiencies of a 12C5+ beam from an electron cyclotron resonance ion source to the cyclotron were measured for various conditions of the ion source. Moreover, a feasible region for acceleration in the emittance of the injection beam was clarified using a transverse-acceptance measuring system. We confirmed that the beam emittance and profile were changed depending on the condition of the ion source and that matching between the beam emittance and the acceptance of the cyclotron was degraded. However, after fine-tuning to improve the matching, beam intensity downstream of the cyclotron increased.
Identification of structure in condensed matter with the topological cluster classification
Authors: Malins Alex , Williams Stephen R. , Eggers Jens , Royall C. Patrick
Published: December 2013

We describe the topological cluster classification (TCC) algorithm. The TCC detects local structures with bond topologies similar to isolated clusters which minimise the potential energy for a number of monatomic and binary simple liquids with m ⩽ 13 particles. We detail a modified Voronoi bond detection method that optimizes the cluster detection. The method to identify each cluster is outlined, and a test example of Lennard-Jones liquid and crystal phases is considered and critically examined.
Schottky barrier source-gated ZnO thin film transistors by low temperature atomic layer deposition
Authors: Ma Alex M. , Gupta Manisha , Afshar Amir , Shoute Gem , Tsui Ying Y. , Cadien Kenneth C. , Barlage Douglas W.
Published: December 2013

We have fabricated ZnO source-gated thin film transistors (SGTFTs) with a buried TiW source Schottky barrier and a top gate contact. The ZnO active channel and thin high-κ HfO2 dielectric utilized are both grown by atomic layer deposition at temperatures less than 130 °C, and their material and electronic properties are characterized. These SGTFTs demonstrate enhancement-mode operation with a threshold voltage of 0.91 V, electron mobility of 3.9 cm2 V−1 s−1, and low subthreshold swing of 192 mV/decade. The devices also exhibit a unique combination of high breakdown voltages (>20 V) with low output conductances.
Optimal system size for complex dynamics in random neural networks near criticality
Authors: Wainrib Gilles , del Molino Luis Carlos García
Published: December 2013

In this article, we consider a model of dynamical agents coupled through a random connectivity matrix, as introduced by Sompolinsky et al. [Phys. Rev. Lett. 61(3), 259–262 (1988)] in the context of random neural networks. When system size is infinite, it is known that increasing the disorder parameter induces a phase transition leading to chaotic dynamics. We observe and investigate here a novel phenomenon in the sub-critical regime for finite size systems: the probability of observing complex dynamics is maximal for an intermediate system size when the disorder is close enough to criticality. We give a more general explanation of this type of system size resonance in the framework of extreme values theory for eigenvalues of random matrices.
Integral momentum balance on a growing bubble
Authors: Siedel S. , Cioulachtjian S. , Robinson A. J. , Bonjour J.
Published: December 2013

The integral momentum balance on a growing boiling bubble is investigated. All forces acting on the bubble are detailed, and the methods and assumptions used to calculate their integral resultants are discussed. The momentum balance computation is then performed using experimental data of bubbles growing on an artificial nucleation site in a controlled environment. The relative magnitude of each force component is compared, showing negligible dynamic forces, upwards forces composed mainly of the buoyancy and contact pressure components, and downwards forces being exclusively due to surface tension and adhesion. The difficulty encountered in measuring the apparent contact angle due to mirage effects has been highlighted; a new method, fitting numerically simulated bubble profile to the contour measurements has been proposed and used to correct the effects of refraction on the bubble profile determination. As all forces acting on the bubble were measured, it was possible to estimate the residuals of the momentum balance. Their small value validated both the expressions used for the forces and the methodology to evaluate their value.
Symmetrical windowing for quantum states in quasi-classical trajectory simulations: Application to electronically non-adiabatic processes
Authors: Cotton Stephen J. , Miller William H.
Published: December 2013

A recently described symmetrical windowing methodology [S. J. Cotton and W. H. Miller, J. Phys. Chem. A 117, 7190 (2013)] for quasi-classical trajectory simulations is applied here to the Meyer-Miller [H.-D. Meyer and W. H. Miller, J. Chem. Phys. 70, 3214 (1979)] model for the electronic degrees of freedom in electronically non-adiabatic dynamics. Results generated using this classical approach are observed to be in very good agreement with accurate quantum mechanical results for a variety of test applications, including problems where coherence effects are significant such as the challenging asymmetric spin-boson system.
Agent-based station for on-line diagnostics by self-adaptive laser Doppler vibrometry
Authors: Serafini S. , Paone N. , Castellini P.
Published: December 2013

A self-adaptive diagnostic system based on laser vibrometry is proposed for quality control of mechanical defects by vibration testing; it is developed for appliances at the end of an assembly line, but its characteristics are generally suited for testing most types of electromechanical products. It consists of a laser Doppler vibrometer, equipped with scanning mirrors and a camera, which implements self-adaptive bahaviour for optimizing the measurement. The system is conceived as a Quality Control Agent (QCA) and it is part of a Multi Agent System that supervises all the production line. The QCA behaviour is defined so to minimize measurement uncertainty during the on-line tests and to compensate target mis-positioning under guidance of a vision system. Best measurement conditions are reached by maximizing the amplitude of the optical Doppler beat signal (signal quality) and consequently minimize uncertainty. In this paper, the optimization strategy for measurement enhancement achieved by the down-hill algorithm (Nelder-Mead algorithm) and its effect on signal quality improvement is discussed. Tests on a washing machine in controlled operating conditions allow to evaluate the efficacy of the method; significant reduction of noise on vibration velocity spectra is observed. Results from on-line tests are presented, which demonstrate the potential of the system for industrial quality control.
A simplified model for thermal-wave cavity self-consistent measurement of thermal diffusivity
Authors: Shen Jun , Zhou Jianqin , Gu Caikang , Neill Stuart , Michaelian Kirk H. , Fairbridge Craig , Astrath Nelson G. C. , Baesso Mauro L.
Published: December 2013

A simplified theoretical model was developed for the thermal-wave cavity (TWC) technique in this study. This model takes thermal radiation into account and can be employed for absolute measurements of the thermal diffusivity of gas and liquid samples without any knowledge of geometrical and thermal parameters of the components of the TWC. Using this model and cavity-length scans, thermal diffusivities of air and distilled water were accurately and precisely measured as (2.191 ± 0.004) × 10−5 and (1.427 ± 0.009) × 10−7 m2 s−1, respectively, in very good agreement with accepted literature values.
Self-consistent mean-field theory of size distribution narrowing during ramped temperature ion beam synthesis
Authors: Mastandrea J. P. , Sherburne M. P. , Boswell-Koller C. N. , Sawyer C. A. , Guzman J. , Bustillo K. C. , Ager J. W. , Haller E. E. , Chrzan D. C.
Published: December 2013

A simple mathematical argument explains a recently identified route for the ion beam synthesis of nanoclusters with a narrowed size distribution. The key idea is that growth conditions for which the average nanocluster size is increasing rapidly can lead to narrowed size distributions. Modeling candidate processes using a self-consistent, mean-field theory shows that normalized nanocluster size distributions with full-width at half-maximum of 17% of the average can be attained.
High-gain X-ray free electron laser by beat-wave terahertz undulator
Authors: Chang Chao , Hei DongWei , Pellegrin Claudio , Tantawi Sami
Published: December 2013

The THz undulator has a higher gain to realize a much brighter X-ray at saturation, compared with the optical undulator under the same undulator strength and beam quality. In order to fill the high-power THz gap and realize the THz undulator, two superimposed laser pulses at normal incidence to the electron-beam moving direction form an equivalent high-field THz undulator by the frequency difference to realize the high-gain X-ray Free electron laser. The pulse front tilt of lateral fed lasers is used to realize the electron-laser synchronic interaction. By PIC simulation, a higher gain and a larger X-ray radiation power by the beat wave THz undulator could be realized, compared with the optical undulator for the same electron beam parameters.
Momentum imaging spectrometer for molecular fragmentation dynamics induced by pulsed electron beam
Authors: Wang EnLiang , Shan Xu , Shi YuFeng , Tang YaGuo , Chen XiangJun
Published: December 2013

A momentum imaging spectrometer has been built for studying the electron impact molecular fragmentation dynamics. The setup consists of a pulsed electron gun and a time of flight system as well as a two-dimensional time and position sensitive multi-hit detector. The charged fragments with kinetic energy up to 10 eV can be detected in 4π solid angles and their three-dimensional momentum vectors can be reconstructed. The apparatus is tested by electron impact ionization of Ar and dissociative ionization of CO2. By analyzing the ion-ion coincidence spectra, the complete and incomplete Coulomb fragmentation channels for \documentclass[12pt]{minimal}\begin{document}${\rm CO}_2^{2+}$\end{document} CO 22+ and \documentclass[12pt]{minimal}\begin{document}${\rm CO}_2^{3+}$\end{document} CO 23+ are identified. The kinetic energy release (KER) and angular correlation for the two-body breakup channel \documentclass[12pt]{minimal}\begin{document}${\rm CO}_2^{2+*}$\end{document} CO 22+* → O+ + CO+ are reported. The peak value of total KER is found to be 6.8 eV which is consistent with the previous photoion-photoion coincidence studies, and the correlation angle of O+ and CO+ is also explicitly determined to be 172.5°.
Edible oil structures at low and intermediate concentrations. II. Ultra-small angle X-ray scattering of in situ tristearin solids in triolein
Authors: Peyronel Fernanda , Ilavsky Jan , Mazzanti Gianfranco , Marangoni Alejandro G. , Pink David A.
Published: December 2013

Ultra-small angle X-ray scattering has been used for the first time to elucidate, in situ, the aggregation structure of a model edible oil system. The three-dimensional nano- to micro-structure of tristearin solid particles in triolein solvent was investigated using 5, 10, 15, and 20% solids. Three different sample preparation procedures were investigated: two slow cooling rates of 0.5°/min, case 1 (22 days of storage at room temperature) and case 2 (no storage), and one fast cooling of 30°/min, case 3 (no storage). The length scale investigated, by using the Bonse-Hart camera at beamline ID-15D at the Advanced Photon Source, Argonne National Laboratory, covered the range from 300 Å to 10 μm. The unified fit and the Guinier-Porod models in the Irena software were used to fit the data. The former was used to fit 3 structural levels. Level 1 structures showed that the primary scatterers were essentially 2-dimensional objects for the three cases. The scatterers possessed lateral dimensions between 1000 and 4300 Å. This is consistent with the sizes of crystalline nanoplatelets present which were observed using cryo-TEM. Level 2 structures were aggregates possessing radii of gyration, Rg2 between 1800 Å and 12000 Å and fractal dimensions of either D2=1 for case 3 or 1.8≤D2≤2.1 for case 1 and case 2. D2 = 1 is consistent with unaggregated 1-dimensional objects. 1.8 ≤ D2 ≤ 2.1 is consistent with these 1-dimensional objects (below) forming structures characteristic of diffusion or reaction limited cluster-cluster aggregation. Level 3 structures showed that the spatial distribution of the level 2 structures was uniform, on the average, for case 1, with fractal dimension D3≈3 while for case 2 and case 3 the fractal dimension was D3≈2.2, which suggested that the large-scale distribution had not come to equilibrium. The Guinier-Porod model showed that the structures giving rise to the aggregates with a fractal dimension given by D2 in the unified fit level 2 model were cylinders described by the parameter s≈1 in the Guinier-Porod model. The size of the base of these cylinders was in agreement with the cryo-TEM observations as well as with the results of the level 1 unified fit model. By estimating the size of the nanoplatelets and understanding the structures formed via their aggregation, it will be possible to engineer novel lipids systems that embody desired functional characteristics.
Linearized Jastrow-style fluctuations on spin-projected Hartree-Fock
Authors: Henderson Thomas M. , Scuseria Gustavo E.
Published: December 2013

The accurate and efficient description of strong electronic correlations remains an important objective in electronic structure theory. Projected Hartree-Fock theory, where symmetries of the Hamiltonian are deliberately broken and projectively restored, all with a mean-field computational scaling, shows considerable promise in this regard. However, the method is neither size extensive nor size consistent; in other words, the correlation energy per particle beyond broken-symmetry mean field vanishes in the thermodynamic limit, and the dissociation limit of a molecule is not the sum of the fragment energies. These two problems are closely related. Recently, Neuscamman [Phys. Rev. Lett. 109, 203001 (2012)] has proposed a method to cure the lack of size consistency in the context of the antisymmetrized geminal power wave function (equivalent to number-projected Hartree-Fock-Bogoliubov) by using a Jastrow-type correlator in Hilbert space. Here, we apply the basic idea in the context of projected Hartree-Fock theory, linearizing the correlator for computational simplicity but extending it to include spin fluctuations. Results are presented for the Hubbard Hamiltonian and for some simple molecular systems.
Measurement of temperature-dependent stress in copper-filled silicon vias using polarized Raman spectroscopy
Authors: Sugie Ryuichi , Kosaka Kenichi , Seki Hirofumi , Hashimoto Hideki , Yoshikawa Masanobu
Published: December 2013

An experimental method to determine the temperature dependence of residual stress in three-dimensional (3D) structures was developed using polarized Raman spectroscopy. Stresses of a copper-filled silicon via at three temperatures, 223, 298, and 413 K were derived by measuring the frequency shift of the optical phonons through the backscattering geometry from the cross-section of the structure and assuming non-isotropic biaxial (horizontal and depth) stresses on the cross-section. Both stress components changed from tensile to compressive in almost all areas as the temperature changed from 213 to 413 K. The absolute stress values increased at both low and high temperatures and were smallest at 298 K, which was nearest to the process temperature of copper filling by plating. The main cause of stress is considered to be the difference in the coefficient of thermal expansion between copper and silicon. These results indicate that the temperature dependence of stress of copper-filled vias is affected mainly by their fabrication temperature. Process temperature is one of the key factors for the reduction of thermal stress in 3D structures such as integrated circuits connected by through-silicon vias.
Interpretation of time-of-flight distributions for neutral particles under pulsed laser evaporation using direct Monte Carlo simulation
Authors: Morozov Alexey A.
Published: December 2013

A theoretical study of the time-of-flight (TOF) distributions under pulsed laser evaporation in vacuum has been performed. A database of TOF distributions has been calculated by the direct simulation Monte Carlo (DSMC) method. It is shown that describing experimental TOF signals through the use of the calculated TOF database combined with a simple analysis of evaporation allows determining the irradiated surface temperature and the rate of evaporation. Analysis of experimental TOF distributions under laser ablation of niobium, copper, and graphite has been performed, with the evaluated surface temperature being well agreed with results of the thermal model calculations. General empirical dependences are proposed, which allow indentifying the regime of the laser induced thermal ablation from the TOF distributions for neutral particles without invoking the DSMC-calculated database.
Strong shock generation by fast electron energy deposition
Authors: Fox T. E. , Robinson A. P. L. , Pasley J.
Published: December 2013

It has been suggested that fast electrons may play a beneficial role in the formation of the ignitor shock in shock ignition owing to the high areal density of the fuel at the time of the ignitor pulse. In this paper, we extend previous studies which have focused on monoenergetic electron sources to populations with extended energy distributions. In good agreement with analytic scalings, we show that strong shocks can be produced with peak pressures of a few hundred Mbar to over 1 Gbar using fast electron intensities of 1–10 PW/cm2 in a uniform deuterium-tritium plasma at 10 g/cm3. However, the length required for shock formation increases with fast electron temperature. As this shock formation distance becomes comparable to the target size, the shock is not able to fully develop, and this implies a limit on the ability of fast electrons to aid shock formation.
Determination of transition probabilities for the 3p → 3s transition array in neon using laser induced breakdown spectroscopy
Authors: Asghar Haroon , Ali Raheel , Baig M. Aslam
Published: December 2013

We present here a study of the optical emission spectra of the laser produced neon plasma generated by a Nd:YAG laser at 1064 nm. The spectra were recorded using the laser induced breakdown spectroscopy 2000 detection system comprising of five spectrometers covering the entire visible region. The observed spectra yield all the optically allowed transitions between the 2p53p upper and 2p53s lower configurations based levels. The relative line strengths of all the dipole allowed transitions have been determined using the intensity ratios and compared with the J-file sum rule. The absolute transition probabilities have been calculated by using the lifetimes of the upper levels and the intensities of the observed spectral lines and show good agreement with the literature values.
Development of a high-temperature oven for the 28 GHz electron cyclotron resonance ion source
Authors: Ohnishi J. , Higurashi Y. , Kidera M. , Ozeki K. , Nakagawa T.
Published: December 2013

We have been developing the 28 GHz ECR ion source in order to accelerate high-intensity uranium beams at the RIKEN RI-beam Factory. Although we have generated U35+ beams by the sputtering method thus far, we began developing a high-temperature oven with the aim of increasing and stabilizing the beams. Because the oven method uses UO2, a crucible must be heated to a temperature higher than 2000 °C to supply an appropriate amount of UO2 vapor to the ECR plasma. Our high-temperature oven uses a tungsten crucible joule-heated with DC current of approximately 450 A. Its inside dimensions are ϕ11 mm × 13.5 mm. Since the crucible is placed in a magnetic field of approximately 3 T, it is subject to a magnetic force of approximately 40 N. Therefore, we used ANSYS to carefully design the crucible, which was manufactured by machining a tungsten rod. We could raise the oven up to 1900 °C in the first off-line test. Subsequently, UO2 was loaded into the crucible, and the oven was installed in the 28 GHz ECR ion source and was tested. As a result, a U35+ beam current of 150 μA was extracted successfully at a RF power of approximately 3 kW.
Subcutaneous oxidation of In0.53Ga0.47As(100) through ultra-thin atomic layer deposited Al2O3
Authors: Ahn Jaesoo , McIntyre Paul C.
Published: December 2013

Stability of oxide/semiconductor interfaces during device fabrication is critically important, particularly for adoption of new semiconductor channel materials, such as III-V compounds. Unintentional oxidation of an underlying In0.53Ga0.47As(100) surface through atomic layer deposited (ALD) Al2O3 layers of varying thickness is investigated. Oxygen annealing of 1 ∼ 2 nm thickness Al2O3 layers at 300 °C or higher and large-dose water vapor exposure during the ALD-Al2O3 process at 300 °C produces InGaAs surface oxidation. This subcutaneous oxidation of InGaAs increases the Al2O3/InGaAs interface defect density as observed in suppressed band-edge photoluminescence and in capacitance-voltage analysis, possibly by creating As dangling bonds at the InGaAs surface.
Light induced modulation instability of surfaces under intense illumination
Authors: Burlakov V. M. , Foulds I. , Goriely A.
Published: December 2013

We show that a flat surface of a polymer in rubber state illuminated with intense electromagnetic radiation is unstable with respect to periodic modulation. Initial periodic perturbation is amplified due to periodic thermal expansion of the material heated by radiation. Periodic heating is due to focusing-defocusing effects caused by the initial surface modulation. The surface modulation has a period longer than the excitation wavelength and does not require coherent light source. Therefore, it is not related to the well-known laser induced periodic structures on polymer surfaces but may contribute to their formation and to other phenomena of light-matter interaction.
Enhanced second-harmonic generation in Pr0.5Ca0.5MnO3/La0.5Sr0.5MnO3 superlattices
Authors: Lee J. S. , Nakamura M. , Kawasaki M. , Tokura Y.
Published: December 2013

We investigated second harmonic generation for manganite superlattices composed of Pr0.5Ca0.5MnO3 and La0.5Sr0.5MnO3. While the second harmonic intensity shows a strong variation as a function of the constituent layer thickness, it is dramatically enhanced when each layer has a same thickness of about 1.4 nm and endows its own ground state nature, i.e., a charge-orbital ordered antiferromagnetic insulator for Pr0.5Ca0.5MnO3 and a ferromagnetic metal for La0.5Sr0.5MnO3. From the detailed symmetry analysis, we discuss a possible role of the coexisting phases and their boundaries in the enhancement of the polar character in this manganese oxide superlattice.
Evidence for graphite-like hexagonal AlN nanosheets epitaxially grown on single crystal Ag(111)
Authors: Tsipas P. , Kassavetis S. , Tsoutsou D. , Xenogiannopoulou E. , Golias E. , Giamini S. A. , Grazianetti C. , Chiappe D. , Molle A. , Fanciulli M. , Dimoulas A.
Published: December 2013

Ultrathin (sub-monolayer to 12 monolayers) AlN nanosheets are grown epitaxially by plasma assisted molecular beam epitaxy on Ag(111) single crystals. Electron diffraction and scanning tunneling microscopy provide evidence that AlN on Ag adopts a graphite-like hexagonal structure with a larger lattice constant compared to bulk-like wurtzite AlN. This claim is further supported by ultraviolet photoelectron spectroscopy indicating a reduced energy bandgap as expected for hexagonal AlN.
Spin-wave spectra and stability of the in-plane vortex state in two-dimensional magnetic nanorings
Authors: Mamica S.
Published: December 2013

We study theoretically two-dimensional nanorings assumed to have the in-plane vortex magnetic configuration. Using a discrete dipole model we examine the spectrum of normal spin-wave modes vs. the dipolar-to-exchange interaction ratio. We systematize the spin-wave excitations by their azimuthal and radial wave numbers. The lowest-frequency mode, the fundamental (quasiuniform) mode, and the mode hybridization are analyzed; the discussion of the influence of effective pinning at the ring boundaries is provided as well. We study the stability of the in-plane vortex state and discuss the role of the size of the ring and the type of lattice arrangement of the magnetic moments within it. To facilitate comparison with our results we provide the relationships between microscopic parameters, used in our model, and those used in the case of continuous medium.
Fast deterministic switching in orthogonal spin torque devices via the control of the relative spin polarizations
Authors: Park Junbo , Ralph D. C. , Buhrman R. A.
Published: December 2013

We model 100 ps pulse switching dynamics of orthogonal spin transfer (OST) devices that employ an out-of-plane polarizer and an in-plane polarizer. Simulation results indicate that increasing the spin polarization ratio, CP = PIPP/POPP, results in deterministic switching of the free layer without over-rotation (360° rotation). By using spin torque asymmetry to realize an enhanced effective PIPP, we experimentally demonstrate this behavior in OST devices in parallel to anti-parallel switching. Modeling predicts that decreasing the effective demagnetization field can substantially reduce the minimum CP required to attain deterministic switching, while retaining low critical switching current, Ip ∼ 500 μA.
Metal-semiconductor hybrid thin films in field-effect transistors
Authors: Okamura Koshi , Dehm Simone , Hahn Horst
Published: December 2013

Metal-semiconductor hybrid thin films consisting of an amorphous oxide semiconductor and a number of aluminum dots in different diameters and arrangements are formed by electron beam lithography and employed for thin-film transistors (TFTs). Experimental and computational demonstrations systematically reveal that the field-effect mobility of the TFTs enhances but levels off as the dot density increases, which originates from variations of the effective channel length that strongly depends on the electric field distribution in a transistor channel.
Evaluation of photovoltaic materials within the Cu-Sn-S family
Authors: Zawadzki Pawel , Baranowski Lauryn L. , Peng Haowei , Toberer Eric S. , Ginley David S. , Tumas W. , Zakutayev Andriy , Lany Stephan
Published: December 2013

Next-generation thin film solar cell technologies require earth abundant photovoltaic absorber materials. Here we demonstrate an alternative approach to design of such materials, evaluating candidates grouped by constituent elements rather than underlying crystal structures. As an example, we evaluate thermodynamic stability, electrical transport, electronic structure, optical and defect properties of Cu-Sn-S candidates using complementary theory and experiment. We conclude that Cu2SnS3 avoids many issues associated with the properties of Cu4SnS4, Cu4Sn7S16, and other Cu-Sn-S materials. This example demonstrates how this element-specific approach quickly identifies potential problems with less promising candidates and helps focusing on the more promising solar cell absorbers.
Binder-free Ge-three dimensional graphene electrodes for high-rate capacity Li-ion batteries
Authors: Wang C. D. , Chui Y. S. , Li Y. , Chen X. F. , Zhang W. J.
Published: December 2013

A binder-free, high-rate Ge-three dimensional (3D) graphene composite was synthesized by directly depositing Ge film atop 3D graphene grown by microwave plasma chemical vapor deposition on Ni substrate. The Ge-3D graphene structure demonstrates excellent electrochemical performance as a lithium ion battery (LIB) anode with a reversible capacity of 1140 mAh g−1 at 1/3C over 100 cycles and 835 mAh g−1 at 8C after 60 cycles, and significantly a discharge capacity of 186 mAh g−1 was still achieved at 32C. The high capacity and outstanding stability of the Ge-3D graphene composite propose it as a promising electrode in high-performance thin film LIBs.
Forming-free resistive switching characteristics of 15 nm-thick multicomponent oxide
Authors: Tulu Berhanu , Chang W. Z. , Chu Jinn P. , Wang S. F.
Published: December 2013

Resistive switching (RS) characteristics and mechanism of multicomponent oxide (MCO) memory device are studied. MCO based on an amorphous (ZrCuAlNi)Ox active layer with a thin thickness of ∼15 nm is sputter deposited without substrate heating or post-annealing. The device shows forming-free unipolar RS properties of low operation voltage (<1.7 V), long retention time, good endurance, and resistance ratio. The RS property is considered to be dominated by the filamentary conduction due to the presence of oxygen vacancies in the grain boundary-free structure.
Large area, low capacitance, GaAs nanowire photodetector with a transparent Schottky collecting junction
Authors: Seyedi M. A. , Yao M. , O'Brien J. , Wang S. Y. , Dapkus P. D.
Published: December 2013

We present experimental results on a GaAs/Indium-Tin-Oxide Schottky-like heterojunction photodetector based on a nanowire device geometry. By distributing the active detecting area over an array of nanowires, it is possible to achieve large area detection with low capacitance. Devices with bare GaAs and passivated AlGaAs/GaAs nanowires are fabricated to compare the responsivity with and without surface passivation. We are able to achieve responsivity of >0.5A/W and Signal-Noise-Ratio in excess of 7 dB for 2 V applied reverse bias with passivated nanowire devices. Capacitance-voltage measurement yields <5 nF/cm2, which shows a strong possibility for high-speed applications with a broad area device.
Temperature-dependent quantum efficiency of Ga(N,As,P) quantum wells
Authors: Rosemann N. W. , Metzger B. , Kunert B. , Volz K. , Stolz W. , Chatterjee S.
Published: December 2013

The photoluminescence quantum efficiencies of a series of Ga(N,As,P)/GaP multiple quantum wells are analyzed. The external quantum efficiencies are derived from the absorbed and the emitted light intensities measured using an integrating sphere mounted inside a closed-cycle helium cryostat. By taking into account the device layer sequences as well as internal reflections and reabsorption, the internal quantum efficiencies yield values above 90% for all samples at cryogenic temperatures. The temperature-dependence of the quantum efficiencies as a function of active quantum well layer design reveal the internal interfaces as remaining growth challenge in these heterostructures.
First-cut design of an all-superconducting 100-T direct current magnet
Authors: Iwasa Yukikazu , Hahn Seungyong
Published: December 2013

A 100-T magnetic field has heretofore been available only in pulse mode. This first-cut design demonstrates that a 100-T DC magnet (100 T) is possible. We base our design on: Gadolinium-based coated superconductor; a nested-coil formation, each a stack of double-pancake coils with the no-insulation technique; a band of high-strength steel over each coil; and a 12-T radial-field limit. The 100 T, a 20 mm cold bore, 6-m diameter, 17-m height, with a total of 12 500-km long superconductor, stores an energy of 122 GJ at its 4.2-K operating current of 2400 A. It requires a 4.2-K cooling power of 300 W.
Growth mechanism of atomic layer deposition of zinc oxide: A density functional theory approach
Authors: Afshar Amir , Cadien Kenneth C.
Published: December 2013

Atomic layer deposition of zinc oxide (ZnO) using diethylzinc (DEZ) and water is studied using density functional theory. The reaction pathways between the precursors and ZnO surface sites are discussed. Both reactions proceed by the formation of intermediate complexes on the surface. The Gibbs free energy of the formation of these complexes is positive at temperatures above ∼120 °C and ∼200 °C for DEZ and water half-reactions, respectively. Spectroscopic ellipsometry results show that the growth per cycle changes at approximately the same temperatures.
An electron Talbot-Lau interferometer and magnetic field sensing
Authors: Bach Roger , Gronniger Glen , Batelaan Herman
Published: December 2013

We present a demonstration of a three grating Talbot-Lau interferometer for electrons. As a proof of principle, the interferometer is used to measure magnetic fields. The device is similar to the classical Moiré deflectometer. The possibility to extend this work to build a scaled-up electron deflectometer or interferometer for sensitive magnetic field sensing is discussed.
Negative group velocity propagation in a highly nonlinear fiber embedded in a stimulated Brillouin scattering laser ring cavity
Authors: Deng Dinghuan , Gao Weiqing , Liao Meisong , Duan Zhongchao , Cheng Tonglei , Suzuki Takenobu , Ohishi Yasutake
Published: December 2013

Superluminal propagation at negative group velocity was demonstrated in a highly nonlinear fiber embedded in a stimulated Brillouin scattering laser ring cavity. A maximum advancement of 369 ns and strong Stokes lasing power of 482 mW were observed when the cavity was pumped with a 1 MHz sinusoidal wave modulated signal at the power level of 1 W. The frequency dependence of fast light in this fiber ring cavity was examined with modulation frequencies of 1 kHz to 15 MHz, a maximum fractional advancement of 0.54 was achieved at 10 kHz, and a maximum negative group index of −9480 was demonstrated at 1 kHz.
Ordered multilayer silica-metal nanocomposites for second-order nonlinear optics
Authors: Zdanowicz Mariusz , Harra Juha , Mäkelä Jyrki M. , Heinonen Esa , Ning Tingyin , Kauranen Martti , Genty Goëry
Published: December 2013

We use aerosol synthesis to fabricate ordered metal-silica nanocomposites consisting of alternating layers of pure silica and silica nanoparticles decorated with silver nanodots. These multilayer structures preserve the narrow plasmon resonance of the nanodots even for high optical densities and allow second-harmonic generation due to spontaneous symmetry breaking arising from the interfaces between silica and nanoparticle layers. Our concept opens up perspectives for complex structures for advanced optical applications.
Magnetic-field annealing of inverted polymer:fullerene hybrid solar cells with FePt nanowires as additive
Authors: Chen Chiang-Ting , Hsu Fang-Chi , Li Cheng-Hung , Chen Chia-Chun , Chen Yang-Fang
Published: December 2013

We demonstrate a facile annealing method to improve the polymer chain ordering of poly(3-hexythiophene) (P3HT):fullerene blend triggered by a small amount of FePt nanowires (FePt NWs). By applying a magnetic field perpendicular to the substrate during the solvent drying process, the resulting P3HT:fullerene:FePt NWs film becomes highly optical anisotropy and exhibits a much stronger X-ray diffraction intensity of P3HT. We hypothesize that the coupling force between the FePt NWs and P3HT can assist the polymer chain alignment leading to an improved device performance. The proposed approach is simple and can be applied to other polymer blend systems as well.
Scalar Politics and Local Sustainability: Rethinking Governance and Justice in an Era of Political and Environmental Change
Authors: Lawhon Mary , Patel Zarina
Published: December 2013

The local was institutionalised as a key scale for environmental action at the Earth Summit, and remains salient in discourse, policy, and action. However, given both real changes and geographical insights into the politics of scale in the past twenty years, we suggest it is time to (re)consider this focus. We assess local sustainability through the lens of scalar politics, arguing for the need to consider what challenges particular scale frames foreground and which they silence. We focus on three changes which have occurred in the last twenty years—the growing salience of the Global South, shifts from environmentalism to sustainability, and new governance patterns—and reflect on the significance of these changes for local sustainability. We suggest the local frame occludes questions of international responsibility and justice, and that the changes since Rio require that we reconsider the scalar frame of local sustainability. We conclude by questioning who benefits from the local frame, and when, where, and for whom a focus on local sustainability may be relevant and ethical.
A reassessment of the type locality of the giant rat Solomys salamonis (Rodentia : Muridae) from the Solomon Islands
Authors: Lavery Tyrone H.
Published: December 2013

The Solomon Islands support a diverse and highly endemic rodent fauna. Most species are poorly known and rarely encountered. Solomys salamonis is one such endemic species known only from the holotype collected in 1881. The type locality for the species has been repeatedly confused in the literature, and this uncertainty has hampered attempts to evaluate the status of the species. I reassessed the type locality based on review of the published literature and records and archives of the Australian Museum, Sydney. My review indicates that the type locality is Ugi Island, not Florida Island as widely reported in the recent literature. A subsequent, preliminary survey on Ugi Island failed to confirm the presence of the species; however, the occurrence of some original forest on Ugi Island encourages further detailed surveys to determine whether S. salamonis is still extant.
Synthesis and Phase Transfer of Monodisperse Iron Oxide (Fe3O4) Nanocubes
Authors: Dewi Melissa R. , Skinner William M. , Nann Thomas
Published: December 2013

Cube-shaped magnetic iron oxide nanoparticles were synthesised and studied with the aim to achieve superior magnetic properties. This study describes a straightforward and simple synthesis method for preparing monodisperse 11–14-nm superparamagnetic iron oxide nanocubes via an ‘effective monomer’ growth mechanism. The as-synthesised nanoparticles are insoluble in water. However, substitution of the non-polar ligands of the particles using a new method that involved an ionic compound generated colloidally stable and water dispersible cube-shaped particles with a very small hydrodynamic diameter. The cubes displayed superior magnetic properties over spherical particles.
Organic fluorine content in aqueous film forming foams (AFFFs) and biodegradation of the foam component 6 : 2 fluorotelomermercaptoalkylamido sulfonate (6 : 2 FTSAS)
Authors: Weiner Barbara , Yeung Leo W. Y. , Marchington Erin B. , D'Agostino Lisa A. , Mabury Scott A.
Published: December 2013

Environmental context
Total organofluorine and known fluorosurfactants were quantified in 11 aqueous film forming foams (AFFFs) used to extinguish fires in Ontario, Canada, and one commercial AFFF product. By comparing the concentrations of known fluorosurfactants with the total organofluorine, less than 10% of the fluorosurfactants were identified in half of the samples. Our biodegradation experiment with one of the fluorosurfactants using waste-water treatment plant sludge showed that it was a potential source of perfluoroalkyl carboxylates, which are persistent in the environment.

Abstract
Eleven aqueous film forming foam (AFFF) samples that were used to extinguish fires in Ontario, Canada, and one commercial product, were analysed using a variety of analytical techniques to obtain structural information and quantities of organofluorine and known perfluoroalkyl and polyfluoroalkyl substances (PFASs). The NMR spectra of the foams distinguished the fluorosurfactants that were synthesised by either electrochemical fluorination or telomerisation. Total organofluorine content was quantified using total organofluorine–combustion ion chromatography (TOF-CIC), which revealed that the samples contained from 475 to 18 000µgFmL–1. The common AFFF component 6 : 2 fluorotelomermercaptoalkylamido sulfonate (FTSAS) was quantified by liquid chromatography tandem mass spectrometry (LC-MS/MS) together with perfluoroalkane sulfonates (PFSAs), perfluoroalkyl carboxylates (PFCAs) and fluorotelomer sulfonates (FTSAs); in five samples, 6 : 2 FTSAS was present in concentrations greater than 1000µgmL–1. By comparing the concentrations of these quantifiable fluorochemicals with the total organofluorine content, it was evident that in half of the AFFF samples, less than 10% of the fluorochemicals were identified; in two of the samples, perfluorooctane sulfonate (PFOS) accounted for ~50% of the total organofluorine content. Our degradation experiment with 6 : 2 FTSAS using waste-water treatment plant sludge showed that 6 : 2 FTSAS was a potential source of FTSAs, fluorotelomer alcohols and PFCAs in the environment.
Young adult perceptions of Australia's physical activity recommendations for adults
Authors: Jose Kim A. , Cleland Verity J. , Venn Alison J. , Hansen Emily
Published: December 2013

Issues addressed

Physical activity recommendations for adults worldwide advise participation in moderate‐intensity physical activity, such as walking, on most days of the week. Younger adults report the lowest prevalence of walking. This mixed‐methods study explores the salience of Australia's activity recommendations around moderate‐intensity physical activity, particularly walking, for young Australian adults.

Methods

Semistructured interviews were conducted with 24 young Australians aged 17–25 years. During interviews, Australia's physical activity recommendations for adults were explained to participants, highlighting the inclusion of moderate‐intensity physical activity such as walking. Participants were asked to comment on the recommendations and walking for physical activity and exercise. Data from interviews underwent an iterative thematic form of analysis. Participants also completed the International Physical Activity Questionnaire (IPAQ) and were asked to complete a pedometer diary.

Results

No participant was classified as sedentary; twenty three participants reported walking for transport and nine for leisure (IPAQ). During interviews, the majority of participants (n = 20) did not identify walking as physical activity or exercise. Participants focussed on the cardiorespiratory (fitness) benefits associated with physical activity and believed walking was of insufficient intensity to achieve these benefits at their age.

Conclusions

Walking was considered an everyday activity and of insufficient intensity to achieve any health or fitness benefits.

So what?

The belief that only vigorous physical activity conveys any fitness benefits may act as a barrier to participation in moderateintensity physical activity such as walking, particularly among sedentary young people.
Cryptic speciation and species diversity among Australian and New Zealand hornwort taxa of Megaceros (Dendrocerotaceae)
Authors: Cargill D. Christine , Vella Nicole G. F. , Sharma Ish , Miller Joseph T.
Published: December 2013

Recent molecular studies have redefined families and genera within the anthocerotes, but species boundaries are only now being revised. Monophyly of Australian and New Zealand taxa within the genus Megaceros Campb., which share the same spore and similar gametophyte morphology, was assessed. On the basis of sequence data, mainland Australian lineages are not monophyletic but are interspersed with New Zealand lineages. There are three species present in Australia, including the common and widespread M. gracilis (Reichardt) Steph., the widespread tropical M. flagellaris (Mitt.) Steph., recognised by its tesselated spores, and a new species, M. austronesophilus, found only in Tasmania and Macquarie Island. None of the currently recognised New Zealand taxa is conspecific with any of the Australian taxa. However, New Zealand lineages were found to be genetically and morphologically more diverse than is currently recognised.
DIRECT MEASUREMENT OF INTERSTELLAR EXTINCTION TOWARD YOUNG STARS USING ATOMIC HYDROGEN Lyα ABSORPTION
Authors: McJunkin Matthew , France Kevin , Schneider P. C. , Herczeg Gregory J. , Brown Alexander , Hillenbrand Lynne , Schindhelm Rebecca N. , Edwards Suzan
Published: December 2013

Interstellar reddening corrections are necessary to reconstruct the intrinsic spectral energy distributions (SEDs) of accreting protostellar systems. The stellar SED determines the heating and chemical processes that can occur in circumstellar disks. Measurement of neutral hydrogen absorption against broad Lyα emission profiles in young stars can be used to obtain the total H i column density (N(H i)) along the line of sight. We measure N(H i) with new and archival ultraviolet observations from the Hubble Space Telescope (HST) of 31 classical T Tauri and Herbig Ae/Be stars. The H i column densities range from log10(N(H i)) ≈19.6–21.1, with corresponding visual extinctions of AV
=0.02–0.72 mag, assuming an RV
of 3.1. We find that the majority of the H i absorption along the line of sight likely comes from interstellar rather than circumstellar material. Extinctions derived from new HST blue-optical spectral analyses, previous IR and optical measurements, and new X-ray column densities on average overestimate the interstellar extinction toward young stars compared to the N(H i) values by ∼0.6 mag. We discuss possible explanations for this discrepancy in the context of a protoplanetary disk geometry.
Ottowia beijingensis sp. nov., isolated from coking wastewater activated sludge, and emended description of the genus Ottowia
Authors: Cao Junwei , Lai Qiliang , Liu Yang , Li Guizhen , Shao Zongze
Published: December 2013

A taxonomic study was carried out on strain GCS-AN-3T, which was isolated from a phenol-degrading consortium enriched from coking wastewater activated sludge of Beijing Shougang Company Limited during the screening of phenol-degrading bacteria. Cells of strain GCS-AN-3T were Gram-stain-negative, short rods, and oxidase-/catalase-positive. Growth was observed at salinities from 0 to 2.5 % and at temperatures from 10 to 37 °C. 16S rRNA gene sequence analysis showed that strain GCS-AN-3T was most closely related to

Ottowia pentelensis

DSM 21699T (96.2 %). The principal fatty acids were summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), C16 : 0, summed feature 8 (C18 : 1ω7c/C18 : 1ω6c) and cyclo C17 : 0. The major respiratory quinone was Q-8. The polar lipids comprised phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and an unknown phospholipid. The G+C content of the genomic DNA was 67.6 mol%. Thiosulfate could be utilized as co-substrate for aerobic growth and was oxidized to sulfate. On the basis of phenotypic, chemotaxonomic and molecular data, strain GCS-AN-3T is considered to represent a novel species of the genus

Ottowia

, for which the name Ottowia beijingensis sp. nov. is proposed (type strain GCS-AN-3T = LMG 27179T = CGMCC 1.12324T = MCCC 1A01410T). An emended description of the genus

Ottowia

is also proposed.