bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulse reverse electrodeposition and characterization of nanocrystalline zinc coatings
Authors: Li Qingyang , Feng Zhongbao , Zhang Jinqiu , Yang Peixia , Li Fenghuan , An Maozhong
Published: October 2014

A nanocrystalline zinc coating is produced by pulse reverse electrodeposition in a sulfate bath with polyacrylamide as the only additive and the mechanical, wear and corrosion resistance properties are evaluated.
Oxidative coupling of 2-naphthol by zeolite-Y supported homo and heterometallic trinuclear acetate clusters
Authors: Das Sameeran Kr. , Mahanta Sanjeev P. , Bania Kusum K.
Published: October 2014

Trinuclear metal-oxo cluster supported on zeolite-Y is found to be efficient catalyst for oxidation of 2-naphthol to BINOL with high turn over frequency.
Hyperbranched polydendrons: a new nanomaterials platform with tuneable permeation through model gut epithelium
Authors: Hatton Fiona L. , Tatham Lee M. , Tidbury Louise R. , Chambon Pierre , He Tao , Owen Andrew , Rannard Steven P.
Published: October 2014

Highly branched vinyl polymers (hyperbranched polydendrons), displaying combinations of dendritic and PEG end groups, have been synthesised using a mixed initiator approach. Nanoprecipitated polydendron particles have exhibited controlled permeation through a gut epithelium model.
Scalable synthesis of a sulfur nanosponge cathode for a lithium–sulfur battery with improved cyclability
Authors: Niu Junjie , Kushima Akihiro , Li Mingda , Wang Ziqiang , Li Wenbin , Wang Chao , Li Ju
Published: October 2014

Here we report a liquid-based, low-cost and reliable synthesis method of a lithium–sulfur composite cathode with improved cyclability.
A novel strategy for the aqueous synthesis of down-/up-conversion nanocomposites for dual-modal cell imaging and drug delivery
Authors: Zhao Peng , Zhang Jing , Zhu Yihua , Yang Xiaoling , Jiang Xin , Yuan Yuan , Liu Changsheng , Li Chunzhong
Published: October 2014

A highly efficient multifunctional nanoplatform for dual-modal luminescence imaging and pH-responsive drug delivery has been developed on the basis of a facile and novel strategy by covalently binding up-conversion luminescent NaYF4:Yb,Er nanoparticles with down-conversion fluorescent AgInS2–ZnS quantum dots.
Quantum dynamical investigation of the simplest Criegee intermediate CH2OO and its O–O photodissociation channels
Authors: Samanta Kousik , Beames Joseph M. , Lester Marsha I. , Subotnik Joseph E.
Published: October 2014

The singlet electronic potential energy surfaces for the simplest Criegee intermediate CH2OO are computed over a two-dimensional reduced subspace of coordinates, and utilized to simulate the photo-initiated dynamics on the S2 (B) state leading to dissociation on multiple coupled excited electronic states. The adiabatic electronic potentials are evaluated using dynamically weighted state-averaged complete active space self-consistent field theory. Quasi-diabatic states are constructed from the adiabatic states by maximizing the charge separation between the states. The dissociation dynamics are then simulated on the diabatically coupled excited electronic states. The B ← X electronic transition with large oscillator strength was used to initiate dynamics on the S2 (B) excited singlet state. Diabatic coupling of the B state with other dissociative singlet states results in about 5% of the population evolving to the lowest spin-allowed asymptote, generating H2CO (X 1A1) and O (1D) fragments. The remaining ∼95% of the population remains on repulsive B state and dissociates to H2CO (a 3A″) and O (3P) products associated with a higher asymptotic limit. Due to the dissociative nature of the B state, the simulated electronic absorption spectrum is found to be broad and devoid of any vibrational structure.
A new feature in the internal heavy isotope distribution in ozone
Authors: Bhattacharya S. K. , Savarino Joel , Michalski G. , Liang Mao-Chang
Published: October 2014

Ozone produced by discharge or photolysis of oxygen has unusually heavy isotopic composition (18O/16O and 17O/16O ratio) which does not follow normal mass fractionation rule: δ17O ∼ 0.52*δ18O, expressed as an anomaly Δ17O = δ17O − 0.52*δ18O. Ozone molecule being an open isosceles triangle can have the heavy isotope located either in its apex or symmetric (s) position or the base or asymmetric (as) position. Correspondingly, one can define positional isotopic enrichment, written as δ18O (s) or δ18O (as) (and similarly for δ17O) as well as position dependent isotope anomaly Δ17O (s) and Δ17O (as). Marcus and co-workers have proposed a semi-empirical model based in principle on the RRKM model of uni-molecular dissociation but with slight modification (departure from statistical randomness assumption for symmetrical molecules) which explains many features of ozone isotopic enrichment. This model predicts that the bulk isotope anomaly is contained wholly in the asymmetric position and the Δ17O (s) is zero. Consequently, Δ17O (as) = 1.5 * Δ17O (bulk) (named here simply as the “1.5 rule”) which has been experimentally confirmed over a range of isotopic enrichment. We now show that a critical re-analysis of the earlier experimental data demonstrates a small but significant departure from this 1.5 rule at the highest and lowest levels of enrichments. This departure provides the first experimental proof that the dynamics of ozone formation differs from a statistical model constrained only by restriction of symmetry. We speculate over some possible causes for the departure.
Microwave characterization of tunable interdigitated capacitances on BaTiSnO3 thin films deposited by sol-gel
Authors: Waldhoff Nicolas , Fasquelle Didier , Blary Karine
Published: October 2014

A complete study of BaTi0.98Sn0.02O3 (BTS) thin films deposited on sapphire substrates by a sol-gel technique with physical and microwave dielectric properties up to 67 GHz is presented. A method derived from the techniques applied to silicon transistors and called de-embedding OPEN-SHORT is used for the extraction of interdigital capacitor features. The measurements allowing the calculations of tunability and loss tangent versus frequency are given from 500 MHz up to 67 GHz and bias points ranging from −20 to +20 V. Our results confirm that the BTS material is a very good candidate for microwave applications.
Dynamic topology and flux rope evolution during non-linear tearing of 3D null point current sheets
Authors: Wyper P. F. , Pontin D. I.
Published: October 2014

In this work, the dynamic magnetic field within a tearing-unstable three-dimensional current sheet about a magnetic null point is described in detail. We focus on the evolution of the magnetic null points and flux ropes that are formed during the tearing process. Generally, we find that both magnetic structures are created prolifically within the layer and are non-trivially related. We examine how nulls are created and annihilated during bifurcation processes, and describe how they evolve within the current layer. The type of null bifurcation first observed is associated with the formation of pairs of flux ropes within the current layer. We also find that new nulls form within these flux ropes, both following internal reconnection and as adjacent flux ropes interact. The flux ropes exhibit a complex evolution, driven by a combination of ideal kinking and their interaction with the outflow jets from the main layer. The finite size of the unstable layer also allows us to consider the wider effects of flux rope generation. We find that the unstable current layer acts as a source of torsional magnetohydrodynamic waves and dynamic braiding of magnetic fields. The implications of these results to several areas of heliophysics are discussed.
Light desorption from an yttrium neutralizer for Rb and Fr magneto-optical trap loading
Authors: Coppolaro V. , Papi N. , Khanbekyan A. , Marinelli C. , Mariotti E. , Marmugi L. , Moi L. , Corradi L. , Dainelli A. , Arikawa H. , Ishikawa T. , Sakemi Y. , Calabrese R. , Mazzocca G. , Tomassetti L. , Ricci L.
Published: October 2014

We present here the first evidence of photodesorption induced by low-intensity non-resonant light from an yttrium thin foil, which works as a neutralizer for Rb and Fr ions beam. Neutral atoms are suddenly ejected from the metal surface in a pulsed regime upon illumination with a broadband flash light and then released in the free volume of a pyrex cells. Here atoms are captured by a Magneto-Optical Trap (MOT), which is effectively loaded by the photodesorption. Loading times of the order of the flash rise time are measured. Desorption is also obtained in the continuous regime, by exploiting CW visible illumination of the metallic neutralizer surface. We demonstrate that at lower CW light intensities vacuum conditions are not perturbed by the photodesorption and hence the MOT dynamics remains unaffected, while the trap population increases thanks to the incoming desorbed atoms flux. Even with the Y foil at room temperature and hence with no trapped atoms, upon visible illumination, the number of trapped atoms reaches 105. The experimental data are then analyzed by means of an analytical rate equation model, which allows the analysis of this phenomenon and its dynamics and allows the determination of critical experimental parameters and the test of the procedure in the framework of radioactive Francium trapping. In this view, together with an extensive investigation of the phenomenon with 85Rb, the first demonstration of the photodesorption-aided loading of a 210Fr MOT is shown.
The mechanism of chemisorption of hydrogen atom on graphene: Insights from the reaction force and reaction electronic flux
Authors: Cortés-Arriagada Diego , Gutiérrez-Oliva Soledad , Herrera Bárbara , Soto Karla , Toro-Labbé Alejandro
Published: October 2014

At the PBE-D3/cc-pVDZ level of theory, the hydrogen chemisorption on graphene was analyzed using the reaction force and reaction electronic flux (REF) theories in combination with electron population analysis. It was found that chemisorption energy barrier is mainly dominated by structural work (∼73%) associated to the substrate reconstruction whereas the electronic work is the greatest contribution of the reverse energy barrier (∼67%) in the desorption process. Moreover, REF shows that hydrogen chemisorption is driven by charge transfer processes through four electronic events taking place as H approaches the adsorbent surface: (a) intramolecular charge transfer in the adsorbent surface; (b) surface reconstruction; (c) substrate magnetization and adsorbent carbon atom develops a sp3 hybridization to form the σC-H bond; and (d) spontaneous intermolecular charge transfer to reach the final chemisorbed state.
Extending DFT-based genetic algorithms by atom-to-place re-assignment via perturbation theory: A systematic and unbiased approach to structures of mixed-metallic clusters
Authors: Weigend Florian
Published: October 2014

Energy surfaces of metal clusters usually show a large variety of local minima. For homo-metallic species the energetically lowest can be found reliably with genetic algorithms, in combination with density functional theory without system-specific parameters. For mixed-metallic clusters this is much more difficult, as for a given arrangement of nuclei one has to find additionally the best of many possibilities of assigning different metal types to the individual positions. In the framework of electronic structure methods this second issue is treatable at comparably low cost at least for elements with similar atomic number by means of first-order perturbation theory, as shown previously [F. Weigend, C. Schrodt, and R. Ahlrichs, J. Chem. Phys. 121, 10380 (2004)]. In the present contribution the extension of a genetic algorithm with the re-assignment of atom types to atom sites is proposed and tested for the search of the global minima of PtHf12 and [LaPb7Bi7]4−. For both cases the (putative) global minimum is reliably found with the extended technique, which is not the case for the “pure” genetic algorithm.
Amorphous FeCoSiB for exchange bias coupled and decoupled magnetoelectric multilayer systems: Real-structure and magnetic properties
Authors: Hrkac V. , Lage E. , Köppel G. , Strobel J. , McCord J. , Quandt E. , Meyners D. , Kienle L.
Published: October 2014

The effect of field annealing for exchanged biased multilayer films is studied with respect to the resultant structural and magnetic film properties. The presented multilayer stacks comprise repeating sequences of Ta/Cu/{1 1 1} textured antiferromagnetic Mn70Ir30/amorphous ferromagnetic Fe70.2Co7.8Si12B10. Within the ferromagnetic layers crystalline filaments are observed. An additional Ta layer between the antiferromagnet and ferromagnet is used in order to investigate and separate the influence of the common Mn70Ir30/Fe70.2Co7.8Si12B10 interface on the occurring filaments and structural changes. In situ and ex situ transmission electron microscopy is used for a comprehensive structure characterization of multilayer stacks for selected temperature stages. Up to 250 °C, the multilayers are structurally unaltered and preserve the as-deposited condition. A deliberate increase to 350 °C exhibits different crystallization processes for the films, depending on the presence of crystal nuclei within the amorphous ferromagnetic layer. The influence of volume-to-surface ratio of the multilayer stacks to the crystallization process is emphasized by the comparison of in situ and ex situ investigations as the respective specimen thickness is changed. Complementary magnetic studies reveal a defined exchange bias obtained at the first annealing step and a decrease of total anisotropy field with partial crystallization after the subsequent annealing at 350 °C.
Streamers generation by small-scale drift-Alfvén waves
Authors: Zhao J. S. , Yu M. Y.
Published: October 2014

Excitation of streamers by modulationally unstable small-scale drift-Alfvén wave (SSDAW) is investigated. It is found that the excitation depends strongly on the propagation direction of the SSDAW, and the ion and electron diamagnetic drift waves are both unstable due to the generation of streamers. It is also shown that zonal flows can be effectively excited by the SSDAW with the propagation direction different from that for streamer excitation.
Ge1-ySny (y = 0.01-0.10) alloys on Ge-buffered Si: Synthesis, microstructure, and optical properties
Authors: Senaratne C. L. , Gallagher J. D. , Jiang Liying , Aoki Toshihiro , Smith D. J. , Menéndez J. , Kouvetakis J.
Published: October 2014

Novel hydride chemistries are employed to deposit light-emitting Ge1-ySny alloys with y ≤ 0.1 by Ultra-High Vacuum Chemical Vapor Deposition (UHV-CVD) on Ge-buffered Si wafers. The properties of the resultant materials are systematically compared with similar alloys grown directly on Si wafers. The fundamental difference between the two systems is a fivefold (and higher) decrease in lattice mismatch between film and virtual substrate, allowing direct integration of bulk-like crystals with planar surfaces and relatively low dislocation densities. For y ≤ 0.06, the CVD precursors used were digermane Ge2H6 and deuterated stannane SnD4. For y ≥ 0.06, the Ge precursor was changed to trigermane Ge3H8, whose higher reactivity enabled the fabrication of supersaturated samples with the target film parameters. In all cases, the Ge wafers were produced using tetragermane Ge4H10 as the Ge source. The photoluminescence intensity from Ge1−ySny/Ge films is expected to increase relative to Ge1−ySny/Si due to the less defected interface with the virtual substrate. However, while Ge1−ySny/Si films are largely relaxed, a significant amount of compressive strain may be present in the Ge1−ySny/Ge case. This compressive strain can reduce the emission intensity by increasing the separation between the direct and indirect edges. In this context, it is shown here that the proposed CVD approach to Ge1−ySny/Ge makes it possible to approach film thicknesses of about 1 μm, for which the strain is mostly relaxed and the photoluminescence intensity increases by one order of magnitude relative to Ge1−ySny/Si films. The observed strain relaxation is shown to be consistent with predictions from strain-relaxation models first developed for the Si1−xGex/Si system. The defect structure and atomic distributions in the films are studied in detail using advanced electron-microscopy techniques, including aberration corrected STEM imaging and EELS mapping of the average diamond–cubic lattice.
Vacancy-type defects induced by grinding of Si wafers studied by monoenergetic positron beams
Authors: Uedono Akira , Mizushima Yoriko , Kim Youngsuk , Nakamura Tomoji , Ohba Takayuki , Yoshihara Nakaaki , Oshima Nagayasu , Suzuki Ryoichi
Published: October 2014

Vacancy-type defects introduced by the grinding of Czochralski-grown Si wafers were studied using monoenergetic positron beams. Measurements of Doppler broadening spectra of the annihilation radiation and the lifetime spectra of positrons showed that vacancy-type defects were introduced in the surface region (<98 nm), and the major defect species were identified as (i) relatively small vacancies incorporated in dislocations and (ii) large vacancy clusters. Annealing experiments showed that the defect concentration decreased with increasing annealing temperature in the range between 100 and 500 °C. After 600–700 °C annealing, the defect-rich region expanded up to about 170 nm, which was attributed to rearrangements of dislocation networks, and a resultant emission of point defects toward the inside of the sample. Above 800 °C, the stability limit of those vacancies was reached and they started to disappear. After the vacancies were annealed out (900 °C), oxygen-related defects were the major point defects and they were located at <25 nm.
Raman scattering of rare earth sesquioxide Ho2O3: A pressure and temperature dependent study
Authors: Pandey Sugandha Dogra , Samanta K. , Singh Jasveer , Sharma Nita Dilawar , Bandyopadhyay A. K.
Published: October 2014

Pressure and temperature dependent Raman scattering studies on Ho2O3 have been carried out to investigate the structural transition and the anharmonic behavior of the phonons. Ho2O3 undergoes a transition from cubic to monoclinic phase above 15.5 GPa, which is partially reversible on decompression. The anharmonic behavior of the phonon modes of Ho2O3 from 80 K to 440 K has been investigated. We find an anomalous line-width change with temperature. The mode Grüneisen parameter of bulk Ho2O3 was estimated from high pressure Raman investigation up to 29 GPa. Furthermore, the anharmonic components were calculated from the temperature dependent Raman scattering.
Anomalous temperature dependence of field emission from W18O49 nanowires caused by surface states and field penetration
Authors: Chen W. Q. , Zhan R. Z. , Deng S. Z. , Xu N. S. , Chen Jun
Published: October 2014

In this paper, we studied how field emission from thermally evaporated W18O49 nanowires depended on temperature. As the temperature changed from 300 K to 723 K, we found anomalous changes in emission current. Below an applied field of ∼12.5 V μm−1, the emission current tended to increase with rising temperature, while above 12.5 V μm−1 the current depended less on temperature in the range of 573–723 K. Furthermore, at high temperatures, we found the Fowler-Nordheim plots of these nanowires to be nonlinear. We believe that the anomalous behavior is associated with surface states at low fields and field penetration at high fields.
Modeling platinum diffusion in silicon
Authors: Badr E. , Pichler P. , Schmidt G.
Published: October 2014

Simulations based on diffusion-limited reaction rates were able for the first time to reproduce platinum profiles in silicon for in-diffusion in a wide temperature range from 730 to 950 °C and out-diffusion associated with the ramping-down of the temperature at the end of an industrial diffusion process at 830 °C. A rigorous analysis of the out-diffusion and short-time in-diffusion profiles allowed narrowing down the parameter range for the intrinsic point defects in silicon.
Friction factor and heat transfer of nanofluids containing cylindrical nanoparticles in laminar pipe flow
Authors: Lin Jianzhong , Xia Yi , Ku Xiaoke
Published: October 2014

Numerical simulations of polyalphaolefins-Al2O3 nanofluids containing cylindrical nanoparticles in a laminar pipe flow are performed by solving the Navier-Stokes equation with term of cylindrical nanoparticles, the general dynamic equation for cylindrical nanoparticles, and equation for nanoparticle orientation. The distributions of particle number and volume concentration, the friction factor, and heat transfer are obtained and analyzed. The results show that distributions of nanoparticle number and volume concentration are non-uniform across the section, with larger and smaller values in the region near the pipe center and near the wall, respectively. The non-uniformity becomes significant with the increase in the axial distance from the inlet. The friction factor decreases with increasing Reynolds number. The relationships between the friction factor and the nanoparticle volume concentration as well as particle aspect ratio are dependent on the Reynolds number. The Nusselt number of nanofluids, directly proportional to the Reynolds number, particle volume concentration, and particle aspect ratio, is higher near the pipe entrance than at the downstream locations. The rate of increase in Nusselt number at lower particle volume concentration is more than that at higher concentration. Finally, the expressions of friction factor and Nusselt number as a function of particle volume concentration, particle aspect ratio, and Reynolds number are derived based on the numerical data.
The peculiarities of magnetization reversal process in magnetic nanotube with helical anisotropy
Authors: Usov N. A. , Serebryakova O. N.
Published: October 2014

The magnetization reversal process in a soft magnetic nanotube with a weak helical magnetic anisotropy is studied by means of numerical simulation. The origin of a helical anisotropy is a small off-diagonal correction to the magneto-elastic energy density. The change of the external magnetic field parallel to the nanotube axis is shown to initiate a magnetic hysteresis associated with the jumps of the circular magnetization component of the nanotube at a critical magnetic field Hs. For a uniform nanotube, the critical magnetic field Hs is investigated as a function of geometrical and magnetic parameters of the nanotube. Using 2D micromagnetic simulation, we study the behavior of a nanotube having magnetic defects in its middle part. In this case, the jump of the circular magnetization component starts at the defect. As a result, two bamboo domain walls appear near the defect and propagate to the nanotube ends. Similar effect may explain the appearance of the bamboo domain walls in a slightly non uniform amorphous ferromagnetic microwire with negative magnetostriction during magnetization reversal process.
Multiferroic CuCrO2 under high pressure: In situ X-ray diffraction and Raman spectroscopic studies
Authors: Garg Alka B. , Mishra A. K. , Pandey K. K. , Sharma Surinder M.
Published: October 2014

The compression behavior of delafossite compound CuCrO2 has been investigated by in situ x-ray diffraction (XRD) and Raman spectroscopic measurements up to 23.2 and 34 GPa, respectively. X-ray diffraction data show the stability of ambient rhombohedral structure up to ∼23 GPa. Material shows large anisotropy in axial compression with c-axis compressibility, κc = 1.26 × 10−3(1) GPa−1 and a-axis compressibility, κa = 8.90 × 10−3(6) GPa−1. Our XRD data show an irreversible broadening of diffraction peaks. Pressure volume data when fitted to 3rd order Birch-Murnaghan equation of state give the value of bulk modulus, B0 = 156.7(2.8) GPa with its pressure derivative, B0′ as 5.3(0.5). All the observed vibrational modes in Raman measurements show hardening with pressure. Appearance of a new mode at ∼24 GPa indicates the structural phase transition in the compound. Our XRD and Raman results indicate that CuCrO2 may be transforming to an ordered rocksalt type structure under compression.
Capping layer growth rate and the optical and structural properties of GaAsSbN-capped InAs/GaAs quantum dots
Authors: Ulloa J. M. , Reyes D. F. , Utrilla A. D. , Guzman A. , Hierro A. , Ben T. , González D.
Published: October 2014

Changing the growth rate during the heteroepitaxial capping of InAs/GaAs quantum dots (QDs) with a 5 nm-thick GaAsSbN capping layer (CL) strongly modifies the QD structural and optical properties. A size and shape transition from taller pyramids to flatter lens-shaped QDs is observed when the CL growth rate is decreased from 1.5 to 0.5 ML/s. This indicates that the QD dissolution processes taking place during capping can be controlled to some extent by the GaAsSbN CL growth rate, with high growth rates allowing a complete preservation of the QDs. However, the dissolution processes are shown to have a leveling effect on the QD height, giving rise to a narrower size distribution for lower growth rates. Contrary to what could be expected, these effects are opposite to the strong blue-shift and improvement of the photoluminescence (PL) observed for higher growth rates. Nevertheless, the PL results can be understood in terms of the strong impact of the growth rate on the Sb and N incorporation into the CL, which results in lower Sb and N contents at higher growth rates. Besides the QD-CL band offsets and QD strain, the different CL composition alters the band alignment of the system, which can be transformed to type-II at low growth rates. These results show the key role of the alloyed CL growth parameters on the resulting QD properties and demonstrate an intricate correlation between the PL spectra and the sample morphology in complex QD-CL structures.
Nanosheet controlled epitaxial growth of PbZr0.52Ti0.48O3 thin films on glass substrates
Authors: Bayraktar M. , Chopra A. , Bijkerk F. , Rijnders G.
Published: October 2014

Integration of PbZr0.52Ti0.48O3 (PZT) films on glass substrates is of high importance for device applications. However, to make use of the superior ferro- and piezoelectric properties of PZT, well-oriented crystalline or epitaxial growth with control of the crystal orientation is a prerequisite. In this article, we report on epitaxial growth of PZT films with (100)- and (110)-orientation achieved by utilizing Ca2Nb3O10 (CNO) and Ti0.87O2 (TO) nanosheets as crystalline buffer layers. Fatigue measurements demonstrated stable ferroelectric properties of these films up to 5 × 109 cycles. (100)-oriented PZT films on CNO nanosheets show a large remnant polarization of 21 μC/cm2 that is the highest remnant polarization value compared to (110)-oriented and polycrystalline films reported in this work. A piezoelectric response of 98 pm/V is observed for (100)-oriented PZT film which is higher than the values reported in the literature on Si substrates.
Surface and sub-surface thermal oxidation of thin ruthenium films
Authors: Coloma Ribera R. , van de Kruijs R. W. E. , Kokke S. , Zoethout E. , Yakshin A. E. , Bijkerk F.
Published: October 2014

A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low density and high density oxides. Nano-columns grow at the surface of the low density oxide layer, with the growth rate being limited by diffusion of ruthenium through the formed oxide film. Simultaneously, with the growth of the columns, sub-surface high density oxide continues to grow limited by diffusion of oxygen or ruthenium through the oxide film.
Influence of interface on structure and magnetic properties of Fe50B50 nanoglass
Authors: Stoesser A. , Ghafari M. , Kilmametov A. , Gleiter H. , Sakurai Y. , Itou M. , Kohara S. , Hahn H. , Kamali S.
Published: October 2014

In contrast to rapidly quenched metallic glasses, nanoglasses consist of two components, namely amorphous nanograins and interfacial regions with distinctively different properties. Various physical methods have been employed to obtain information on the atomistic and magnetic properties of such materials. For the case of a Fe50B50 nanoglass, using high-energy X-ray diffraction, it was found that the short-range order of the nanograins is similar to that of a crystalline FeB alloy. Magnetic Compton scattering shows that the total magnetic moment is the sum of the magnetic moment of the nanograins and the weak magnetic moment of the interfacial regions (μInterface = +0.08 μB). The measured moment of boron agrees (μBoron = −0.08 μB) with linear Muffin-Tin calculations. From the results of Mössbauer and magnetic Compton scattering, it can be concluded that the boron atoms segregate in the interfacial regions, resulting in a reduced boron concentration in the nanograins.
Electromagnetically induced transparency with large group index induced by simultaneously exciting the electric and the magnetic resonance
Authors: Li Hai-ming , Liu Shao-bin , Liu Si-yuan , Zhang Hai-feng
Published: October 2014

In this paper, we numerically and experimentally demonstrate classical analogy of electromagnetically induced transparency (EIT) with simultaneously exciting the electric and the magnetic resonance. The cut wire and the split-ring resonator (SRR) are chosen as the bright and the quasi-dark EIT resonators, respectively. Under incident electromagnetic wave illumination, an EIT-like sharp transmission window can be observed. The group index exceeds 140, which can be applied for slow electromagnetic wave velocity. Furthermore, the underlying physics can be interpreted by the concept of hybridization model. The simultaneous excitation of the electric and the magnetic resonance can make up for the shortcomings of the other existing designs. More importantly, it can enrich metamaterial analogy of electromagnetically induced transparency.
Determination of magneto-optical constant of Fe films with weak measurements
Authors: Qiu Xiaodong , Zhou Xinxing , Hu Dejiao , Du Jinglei , Gao Fuhua , Zhang Zhiyou , Luo Hailu
Published: October 2014

In this letter, a detecting method for the magneto-optical constant is presented by using weak measurements. The photonic spin Hall effect (PSHE), which manifests itself as spin-dependent splitting, is introduced to characterize the magneto-optical constant, and a propagation model to describe the quantitative relation between the magneto-optical constant and the PSHE is established. According to the amplified shift of the PSHE detected by weak measurements, we determinate the magneto-optical constant of the Fe film sample. The Kerr rotation is measured via the standard polarimetry method to verify the rationality and feasibility of our method. These findings may provide possible applications in magnetic physics research.
Graphene in proximity to magnetic insulating LaMnO3
Authors: Cheng Guanghui , Wei Laiming , Cheng Long , Liang Haixing , Zhang Xiaoqiang , Li Hui , Yu Guolin , Zeng Changgan
Published: October 2014

Proximity to functional substrates may enhance the coupling between the quantum degrees of freedom and thus develop nontrivial quantum effects in graphene. Here, we demonstrate the successful fabrication of graphene in proximity to atomically flat magnetic insulating LaMnO3 films. The insulating nature of the LaMnO3 films not only ensures the electronic transport only occur in the graphene layers but also allow them to serve as dielectric layers for gating. Transport measurements reveal anomalous behaviors, including asymmetrical longitudinal magnetoresistivity and nonlinear Hall effect. This work may pave a way toward the realization of intriguing quantum phases in graphene.
Generation and focusing of electron beams with initial transverse-longitudinal correlation
Authors: Harris J. R. , Lewellen J. W. , Poole B. R.
Published: October 2014

In charged particle beams, one of the roles played by space charge is to couple the transverse and longitudinal dynamics of the beam. This can lead to very complex phenomena which are generally studied using computer simulations. However, in some cases models based on phenomenological or analytic approximations can provide valuable insight into the system behavior. In this paper, we employ such approximations to investigate the conditions under which all the slices of a space charge dominated electron beam with slowly varying current could be focused to a waist with the same radius and at the same location, independent of slice current, and show that this can be accomplished approximately if the initial transverse-longitudinal correlation introduced onto the beam by the electron gun is chosen to compensate for the transverse-longitudinal correlation introduced onto the beam in the drift section. The validity of our approximations is assessed by use of progressively more realistic calculations. We also consider several design elements of electron guns that affect the initial correlations in the beams they generate.
Regimes of external optical feedback in 5.6 μm distributed feedback mid-infrared quantum cascade lasers
Authors: Jumpertz L. , Carras M. , Schires K. , Grillot F.
Published: October 2014

External optical feedback is studied experimentally in mid-infrared quantum cascade lasers. These structures exhibit a dynamical response close to that observed in interband lasers, with threshold reduction and optical power enhancement when increasing the feedback ratio. The study of the optical spectrum proves that the laser undergoes five distinct regimes depending on the phase and amplitude of the reinjected field. These regimes are mapped in the plane of external cavity length and feedback strength, revealing unstable behavior only for a very narrow range of operation, making quantum cascade lasers much more stable than their interband counterparts.
Monolithic color-selective ultraviolet (266–315 nm) photodetector based on a wurtzite MgxZn1−xO film
Authors: Hou Y. N. , Mei Z. X. , Liang H. L. , Gu C. Z. , Du X. L.
Published: October 2014

A unique ultraviolet photodetector based on a metal-semiconductor-metal structure was fabricated from a wurtzite MgxZn1−xO film with gradually changing Mg content, homoepitaxially grown on a BeO-buffered ZnO substrate. The BeO layer filtered out the substrate photoresponse. The cutoff wavelength of the photodetector under zero bias was 266 nm with a UV/visible light rejection ratio of greater than 2 orders of magnitude in the deep UV region. Applying a bias, the cutoff wavelength exhibited a prominent continuous redshift from 266 (0 V) to 315 nm (3 V), indicating the capability for multi-band UV detection on a monolithic chip. The bias-controlled wavelength-selective UV photoresponse mechanism occurred in the optically active area in a compositionally distributed MgxZn1−xO alloy that was achieved by molecular epitaxial growth.
Anomalous spectral dependence of optical polarization and its impact on spin detection in InGaAs/GaAs quantum dots
Authors: Puttisong Y. , Huang Y. Q. , Buyanova I. A. , Yang X. J. , Subagyo A. , Sueoka K. , Murayama A. , Chen W. M.
Published: October 2014

We show that circularly polarized emission light from InGaAs/GaAs quantum dot (QD) ensembles under optical spin injection from an adjacent GaAs layer can switch its helicity depending on emission wavelengths and optical excitation density. We attribute this anomalous behavior to simultaneous contributions from both positive and negative trions and a lower number of photo-excited holes than electrons being injected into the QDs due to trapping of holes at ionized acceptors and a lower hole mobility. Our results call for caution in reading out electron spin polarization by optical polarization of the QD ensembles and also provide a guideline in improving efficiency of spin light emitting devices that utilize QDs.
Electro-hydrodynamic shooting phenomenon of liquid metal stream
Authors: Fang Wen-Qiang , He Zhi-Zhu , Liu Jing
Published: October 2014

We reported an electro-hydrodynamic shooting phenomenon of liquid metal stream. A small voltage direct current electric field would induce ejection of liquid metal inside capillary tube and then shooting into sodium hydroxide solution to form discrete droplets. The shooting velocity has positive relationship with the applied voltage, while the droplet size is dominated by the aperture diameter of the capillary nozzle. Further, the motion of the liquid metal droplets can be flexibly manipulated by the electrodes. This effect suggests an easy going way to generate metal droplets in large quantity, which is important from both fundamental and practical aspects.
Excitation of dust acoustic waves by an ion beam in a plasma cylinder with negatively charged dust grains
Authors: Sharma Suresh C. , Kaur Daljeet , Gahlot Ajay , Sharma Jyotsna
Published: October 2014

An ion beam propagating through a plasma cylinder having negatively charged dust grains drives a low frequency electrostatic dust acoustic wave (DAW) to instability via Cerenkov interaction. The unstable wave frequencies and the growth rate increase with the relative density of negatively charged dust grains. The growth rate of the unstable mode scales to the one-third power of the beam density. The real part of the frequency of the unstable mode increases with the beam energy and scales to almost one-half power of the beam energy. The phase velocity, frequency, and wavelength results of the unstable mode are in compliance with the experimental observations.
Activation of mitochondrial protease OMA1 by Bax and Bak promotes cytochrome c release during apoptosis
Authors: Jiang Xian , Jiang Hui , Shen Zhirong , Wang Xiaodong
Published: October 2014

Significance

The release of cytochrome
c
from its normal intermembrane space in mitochondria marks the initiation of apoptosis in mammalian cells. The process is triggered by the aggregation of B-cell leukemia/lymphoma 2 (BCL2)-associated X (Bax) and BCL2-antagonist/killer (Bak) proteins on the surface of mitochondria. We found that a mitochondrial inner membrane protease, OMA1 (overlapping activity with
m
-AAA protease), is specifically activated and is responsible for cleaving another inner membrane protein, optical nerve atrophy 1 (OPA1), upon Bax/Bak aggregation. The cleavage of OPA1 triggers the remodeling of mitochondrial cristae, allowing the majority of cytochrome
c
inside the cristae to be released. This finding provided a more comprehensive understanding of this critical molecular event during apoptosis.
Learning styles, motivation and cognitive flexibility in interpreter training
Authors: Timarová Šárka , Salaets Heidi
Published: October 2014

Admission testing for conference interpreter training programmes traditionally focuses on skills directly related to the interpreting skills, and while soft skills, such as motivation, are recognised as important, they are not systematically tested or researched. The present study attempts to address this gap by exploring three traits and abilities, namely learning styles, motivation and cognitive flexibility, and to relate them to students’ self-selection for interpreting and to their success on final exams. Three tests were used to compare a group of self-selected interpreting students and applicants (n = 32) and a subgroup of conference interpreting students (n = 14) to a control group of undergraduate students (n = 104), from among whom the majority of Lessius University College interpreting students are recruited: the Inventory of Learning Styles (Vermunt & Rijswijk 1987), the Achievement Motivation Test (Hermans 1968/2004) and the Wisconsin Card Sorting Test (Grant & Berg 1948). The results show that self-selected interpreting students are cognitively more flexible and are less negatively affected by anxiety. Compared to the control group, successful conference interpreting students, but not unsuccessful students, are cognitively more flexible and benefit more from some level of anxiety. Moreover, all conference interpreting students are less affected by stress than the control group and seem to have more clearly developed learning preferences.
Evaluating emotional stability as a predictor of interpreter competence and aptitude for interpreting
Authors: Bontempo Karen , Napier Jemina
Published: October 2014

This paper proposes that variance in interpreter performance is dependent on factors of both general cognitive ability and personality. Whilst there is no doubt of the interplay between individual personality traits and job performance across many occupations, the greatest interest lies in determining which traits play the most important role; and to what extent these variables impact on learning and achievement. The paper reports on a study of 110 accredited signed language interpreters in Australia. Psychological constructs of self-efficacy, goal orientation and negative affectivity were measured, as were interpreter ratings of self-perceived competence as practitioners. The most significant finding revealed the dimension of emotional stability (represented on the negative end of the continuum by traits of anxiety and neuroticism, and measured in this study by the negative affectivity scale) as a predictor of interpreter’s self-perceived competence. Based on these findings, recommendations for admission testing and interpreter education curricula are discussed.
Testing aptitude for interpreting
Authors: Russo Mariachiara
Published: October 2014

This longitudinal study on the predictive value of ‘simultaneous’ Italian-to-Italian oral paraphrasing as an aptitude test for interpreting was conducted on 64 conference interpreting students at the University of Bologna (Forlì). All students completed their course with Italian as their ‘A’ language, having passed the entrance examination (which included a paraphrase test, recorded for evaluation) during the period 2004–2006. Using paraphrase as a pre-interpreting aptitude test in a smaller sample, Russo and Pippa (2004) found a significant correlation between course outcome measures (average interpreting exam mark and number of exam sessions needed to pass all interpreting exams) and two of the evaluation parameters for paraphrasing: ‘synonymic substitution’ (use of synonyms and equivalent expressions) and ‘loss of coherence’. The present study examined whether, in a different setting, these two parameters and the students’ actual admission test mark for paraphrase/recall testing correlated with the same outcome measures. Ability to use synonyms showed the highest validity in relation to the number of interpreting exam sessions, correctly classifying 48 out of 64 students (75%) as ‘slow’ (> 6 sessions: test sensitivity = 80%) or ‘fast’ (≤ 6 sessions: test specificity = 71%). Results thus indicate that an oral ‘real time’ paraphrasing test can help identify such prerequisites of effective interpreting as mental flexibility and expressive ability.
More than a feeling
Authors: Elizondo E. Sonny
Published: October 2014

According to rationalist conceptions of moral agency, the constitutive capacities of moral agency are rational capacities. So understood, rationalists are often thought to have a problem with feeling. For example, many believe that rationalists must reject the attractive Aristotelian thought that moral activity is by nature pleasant. I disagree. It is easy to go wrong here because it is easy to assume that pleasure is empirical rather than rational and so extrinsic rather than intrinsic to moral agency, rationalistically conceived. Drawing on underappreciated elements of Kant’s moral psychology, I sketch an alternative form of rationalism, according to which moral activity is by nature pleasant because at least some pleasures are by nature rational.
Essential surfaces of non-negative Euler characteristic in genus two handlebody exteriors
Authors: Koda Yuya , Ozawa Makoto
Published: October 2014

We provide a classification of the essential surfaces of non-negative Euler characteristic in the exteriors of genus two handlebodies embedded in the 3-sphere.
Genes: A Very Short Introduction
Authors: Slack Jonathan
Published: October 2014

What are genes? What do they say about us? Genes: A Very Short Introduction explores the concept of the gene and looks at the discovery, nature, and role of genes in both evolution and development. Explaining the nature of genetic variation in the human population, how hereditary factors were identified as molecules of DNA, and how certain specific mutations can lead to disease, it highlights how DNA variants are used to trace human ancestry and migration, and can also be used by forensic scientists to identify individuals in crime. It also explores issues such as genetic heritability and IQ.
Chops and Trademarks: Asian Trading Ports and Textile Branding, 1840–1920
Authors: Zangger Andreas P.
Published: October 2014

This article is a contribution to the prehistory of modern branding, presenting a case study of the textile trade in colonial Southeast Asia. The visual appearance of brands as well as their social meaning were altered in the cultural encounter of colonial trade. Through these encounters, trademarks were modernized: the reputation of a producer became less important than the distinctiveness of the product.
Commemorating 100 years since Hjort's 1914 treatise on fluctuations in the great fisheries of northern Europe: where we have been, where we are, and where we are going
Authors: Browman Howard I.
Published: October 2014

The year 2014 marks the 100th anniversary of Johan Hjort's seminal treatise, Fluctuations in the great fisheries of northern Europe, viewed in the light of biological research. This special issue of the ICES Journal of Marine Science commemorates this anniversary. The thirty-two articles that appear herein demonstrate the deep influence that Johan Hjort's work has had, and continues to have, on fisheries and marine science.
A comparison of theCaulobacterNA1000 and K31 genomes reveals extensive genome rearrangements and differences in metabolic potential
Authors: Ash Kurt , Brown Theta , Watford Tynetta , Scott LaTia E. , Stephens Craig , Ely Bert
Published: October 2014

The genusCaulobacteris found in a variety of habitats and is known for its ability to thrive in low-nutrient conditions. K31 is a novelCaulobacterisolate that has the ability to tolerate copper and chlorophenols, and can grow at 4°C with a doubling time of 40 h. K31 contains a 5.5 Mb chromosome that codes for more than 5500 proteins and two large plasmids (234 and 178 kb) that code for 438 additional proteins. A comparison of the K31 and theCaulobacter crescentusNA1000 genomes revealed extensive rearrangements of gene order, suggesting that the genomes had been randomly scrambled. However, a careful analysis revealed that the distance from the origin of replication was conserved for the majority of the genes and that many of the rearrangements involved inversions that included the origin of replication. On a finer scale, numerous small indels were observed. K31 proteins involved in essential functions shared 80–95% amino acid sequence identity with theirC. crescentushomologues, while other homologue pairs tended to have lower levels of identity. In addition, the K31 chromosome contains more than 1600 genes with no homologue in NA1000.