bluuebunny/crossref_metadata_2025 huggingface dataset:
Jean-Paul Sartre
Authors: Baldwin Thomas
Published: February 2012

Jean-Paul Sartre (1905–1980), nephew of the Alsatian theologian, Albert Schweitzer, was born in Paris, passed his agrégation at the Ecole Normale Superieure in 1929, and was a lycée teacher between 1931 and 1945. He was called up to the French Army in 1939, captured by the Germans in 1940 and released after the armistice. In 1938 he published a novel, La Nausée, translated by Robert Baldick as Nausea (Harmondsworth: Penguin, 1965), and in 1940, L'Imaginaire: Psychologie phénoménologique de l'imagination, translated by Bernard Frechtman as The Psychology of Imagination (London: Methuen, 1972). His major philosophical work, L'Etre et le Neant, was published in 1943, and translated by Hazel E. Barnes as Being and Nothingness (London: Methuen, 1957). As a novelist he is best known for a trilogy, Chemins de la Liberté (Roads to Freedom), comprising L'Age de raison (1945) translated by E. Sutton as The Age of Reason (Harmondsworth: Penguin, 1961), Le Sursis (1945), translated by E. Sutton as The Reprieve (Harmondsworth: Penguin, 1963) and La Mort dans l'āme (1949), translated by G. Hopkins as Iron in the Soul (Harmondsworth: Penguin, 1965). His main work of literary criticism is Qu'est-ce que la littérature? (1947), translated by B. Frechtman as What is Literature? (London: Methuen, 1950). Plays includeLes Mouches (1943) and Huis Clos (1944), both translated by S. Gilbert and published in one volume, as The Flies and In Camera (London: Hamish Hamilton, 1965).
Spatial quantum search in a triangular network
Authors: ABAL G. , DONANGELO R. , FORETS M. , PORTUGAL R.
Published: February 2012

The spatial search problem consists of minimising the number of steps required to find a given site in a network, with the restriction that only an oracle query or a translation to a neighbouring site is allowed at each step. We propose a quantum algorithm for the spatial search problem on a triangular lattice with N sites and torus-like boundary conditions. The proposed algorithm is a special case of the general framework for abstract search proposed by Ambainis, Kempe and Rivosh (AKR) in Ambainis et al. (2005) and Tulsi in Tulsi (2008) applied to a triangular network. The AKR–Tulsi formalism was employed to show that the time complexity of the quantum search on the triangular lattice is $O(\sqrt{N \log N})$.
HYPERBOLIC DISCOUNTING AND POSITIVE OPTIMAL INFLATION
Authors: Graham Liam , Snower Dennis J.
Published: February 2012

The Friedman rule states that steady-state welfare is maximized when there is deflation at the real rate of interest. Recent work by Khan, King, and Wolman [Review of Economic Studies10 (4), 825–860] uses a richer model but still finds deflation optimal. In an otherwise standard New Keynesian model we show that, if households have hyperbolic discounting, small positive rates of inflation can be optimal. In our baseline calibration, the optimal rate of inflation is 2.1% and remains positive across a wide range of calibrations.
Cognitive mechanisms of word learning in bilingual and monolingual adults: The role of phonological memory
Authors: KAUSHANSKAYA MARGARITA
Published: February 2012

Previous studies have indicated that bilingualism may facilitate lexical learning in adults. The goals of this research were (i) to examine whether bilingual influences on word learning diverge for phonologically-familiar and phonologically-unfamiliar novel words, and (ii) to examine whether increased phonological memory capacity can account for bilingual effects on word learning. In Experiment 1, participants learned phonologically-familiar novel words that were constructed using the phonemes of English – the native language for all participants. In Experiment 2, participants learned phonologically-unfamiliar novel words that included non-English phonemes. In each experiment, bilingual adults were contrasted with two groups of monolingual adults: a high memory-span monolingual group (that matched bilinguals on phonological memory performance) and a low-span monolingual group. Results showed that bilingual participants in both experiments outperformed monolingual participants, both high-span and low-span. High-span monolinguals outperformed low-span monolinguals when learning phonologically-unfamiliar novel words, but not when learning phonologically-familiar novel words. The findings suggest that the bilingual advantage for novel word learning is not contingent on the phonological properties of novel words, and that phonological memory capacity as measured here cannot account for the bilingual effects on learning.
Gezielte Zusatzförderung im Modellprojekt „Schulreifes Kind“
Authors: Hasselhorn Marcus , Schöler Hermann , Schneider Wolfgang , Ehm Jan-Henning , Johnson Miriam , Keppler Isabelle , Krebs Katja , Niklas Frank , Randhawa Eva , Schmiedeler Sandra , Segerer Robin , Wagner Hanna
Published: February 2012

Im Rahmen einer längsschnittlichen Evaluation des Baden-Württemberger Modellprojektes „Schulreifes Kind“ wurden mehr als 900 Kinder des Einschulungsjahrgangs 2009 zu drei Messzeitpunkten vor Schuleintritt und zwei weiteren nach Schuleintritt untersucht. Die hier vorgelegten Datenanalysen wurden zur Klärung der folgenden drei Fragen genutzt: (1) Führen die kompensatorischen Fördermaßnahmen zur Verbesserung schulrelevanter Fertigkeiten bis zum Ende der Kindergartenzeit? (2) Kommt es infolge des Projektes zu einer höheren Einschulungswahrscheinlichkeit? (3) Zeigen sich mittelfristige Wirkungen auf den Erwerb schulischer Fertigkeiten? Die Analysen zeigen, dass die ersten zwei Fragen mit „ja“ beantwortet werden können. Die Frage nach mittelfristigen Transferwirkungen auf den Erwerb schulischer Fertigkeiten muss dagegen zunächst unbeantwortet bleiben. Insgesamt zeigt sich ein vergleichsweise positives Wirkungsmuster der Zusatzförderung im letzten Kindergartenjahr.
„Runde Tische“ im Projekt „Schulreifes Kind“
Authors: Krebs Katja , Ehm Jan-Henning , Hasselhorn Marcus
Published: February 2012

Als eine Form der Zusammenarbeit zwischen pädagogischen Fachkräften und Eltern wurden im Rahmen des Projekts „Schulreifes Kind“ sogenannte „Runde Tische“ eingeführt. Hierbei handelt es sich um Treffen, bei denen gemeinsam die Entwicklung einzelner Kinder betrachtet und mögliche Förderinhalte besprochen werden. In der vorliegenden Arbeit wird anhand einer Fragebogenuntersuchung von N = 516 beteiligten Personen eine Evaluation der „Runden Tische“ vorgenommen. Die Ergebnisse weisen auf eine gute Zusammenarbeit zwischen pädagogischen Fachkräften und Eltern hin, wobei vor allem seitens der pädagogischen Fachkräfte der Wunsch eines noch intensiveren Austauschs deutlich wird. Weiterhin besteht Einigkeit darüber, dass die „Runden Tische“ eine gute Möglichkeit darstellen die Eltern enger in vorschulische Förderentscheidungen einzubinden. Als besonders positiv wird herausgestellt, dass es bei den Treffen zu einem gezielten Austausch über die Kinder aus den unterschiedlichsten Blickwinkeln kommt.
Effekte einer systemisch ausgerichteten Prozessbegleitung auf die Wirksamkeit der Zusatzförderungen im Projekt „Schulreifes Kind“
Authors: Randhawa Eva , Keppler Isabelle , Johnson Miriam , Schöler Hermann
Published: February 2012

Zur Qualitätssicherung wurden die zur Implementierung des Projekts „Schulreifes Kind“ erforderlichen Veränderungsprozesse in Kindergarten und Grundschule professionell durch ein Coaching begleitet. In den Leistungen von über 700 untersuchten Kinder zeigen sich Wechselwirkungen von Förderung und Coaching, d. h., bei den im letzten Kindergartenjahr geförderten Kindern in den gecoachten Einrichtungen lässt sich eine höhere Fördereffektivität im Sinne von Leistungszuwächsen im Wortschatz, in der allgemeinen Sprachleistung und in den mathematischen Vorläuferfertigkeiten im Gegensatz zu jenen in nicht gecoachten Einrichtungen feststellen. Auch bei Berücksichtigung der variablen Gruppengröße in der Einrichtung, Gesamtförderzeit des einzelnen Kindes im Rahmen des Projekts sowie zusätzliche Förderung außerhalb der Einrichtung als Kovariaten bleibt der Effekt bestehen. Die Ergebnisse der vorliegenden Arbeit betonen die Bedeutsamkeit einer Prozessbegleitung von Projektimplementierungen in der frühen Bildung.
The influence of deformation history on the interpretation of seismic anisotropy
Authors: Skemer Philip , Warren Jessica M. , Hirth Greg
Published: February 2012

Seismic anisotropy in the mantle is primarily caused by the lattice‐preferred orientation (LPO) of olivine, which forms and evolves in response to progressive plastic deformation. The style of LPO and its rate of evolution depend on the effects of physiochemical conditions on the microphysics of deformation and recovery. Here, we integrate results from laboratory experiments and naturally deformed shear zones to evaluate how variability in the evolution of olivine LPO modifies existing strategies for interpreting seismic anisotropy. We concentrate on two particular effects. First, we show that olivine A‐ and E‐type LPOs evolve with opposite senses of rotation, producing a wide spectrum of angular relationships between the orientation of fast seismic wave propagation and the direction of flow. Second, we show that the presence of a pre‐existing LPO introduces a lag between changes in deformation kinematics and alignment of the seismic fast direction with the shear direction. The combination of these two factors affects the inference of deformation kinematics from seismic anisotropy and the interpretation of shear wave splitting parameters.
Experiments on upward migration of a liquid‐rich layer in a granular medium: Implications for a crystalline magma chamber
Authors: Shibano Yasuko , Namiki Atsuko , Sumita Ikuro
Published: February 2012

We perform a series of experiments to investigate the situation in which a melt‐rich layer formed by a magma intrusion ascends through a crystalline magma chamber. The initial condition is such that a heavier granular layer overlies a liquid layer. The particles consisting the upper granular layer are in a jammed state, and only the particles near the interface can move to form a dilated boundary layer. The dilated layer detaches from the upper granular layer, and forms downwelling plumes which drive a cellular convection within the liquid‐rich layer. The convection erodes the upper granular layer, and the liquid‐rich layer migrates upwards with time. This upward migration of the liquid‐rich layer differs from the previously known mechanisms of liquid transport; permeable flow in which the liquid migrates at the Darcy velocity, the Stokes settling in which the individual particle settles, and diapirs formed by the Rayleigh‐Taylor instability. We find that the velocity of the upward migration of the liquid‐rich layer can be scaled by the volumetric flux of the liquid ascending through the narrow channel between the particles. The upward migration of the liquid‐rich layer is faster than the Darcy velocity. In a mushy magma chamber whose crystals are in a jammed state, neither the Stokes settling nor the Rayleigh‐Taylor instability can occur. We propose that the upward migration of the melt‐rich layer observed in our experiments can become an efficient mechanism of melt transport in a crystalline magma chamber.
Radiative transfer in ocean turbulence and its effect on underwater light field
Authors: Xu Zao , Guo Xin , Shen Lian , Yue Dick K. P.
Published: February 2012

Turbulence in the upper ocean generates fluctuations in temperature and salinity, which result in variations in inherent optical properties (IOPs) and further change the underwater light field. A simulation‐based study is performed for the radiative transfer (RT) of natural light in the turbulent flows in the upper ocean. For a canonical problem of turbulent shear flow interacting with the sea surface with and without surface waves, large‐eddy simulations are performed for fluid motions and the transport of temperature and salinity. Based on the resolved turbulence temperature and salinity fields, IOP variations are quantified, and the inhomogeneous RT equation is then simulated using a Monte Carlo method. Through the simulations of a variety of cases with different flow, temperature, and salinity conditions, the statistics of downwelling irradiance are quantified and analyzed. It is found that the vertical profile of the mean downwelling irradiance is mainly determined by the vertical structure of the mean values of the IOPs; and turbulence effect is manifested in the horizontal variations of the downwelling irradiance. The magnitude of the irradiance variation is governed by the differences in the temperature and salinity between their values at the surface and in the deep region. In the presence of surface waves, the irradiance variation is enhanced due to the surface deformation, which is also largely affected by wave–turbulence interaction. The LES and inhomogeneous RT simulation may provide a useful tool for the characterization of upper‐ocean turbulence processes based on underwater RT measurements.
Relationships between lightning flash rates and radar reflectivity vertical structures in thunderstorms over the tropics and subtropics
Authors: Liu Chuntao , Cecil Daniel J. , Zipser Edward J. , Kronfeld Kevin , Robertson Roy
Published: February 2012

Relationships between the vertical profile of radar reflectivity and lightning flash rates are investigated using 13 years of Tropical Rainfall Measuring Mission (TRMM) observations during 1998–2010. First the Radar Precipitation Features (RPFs) are defined by grouping raining areas detected by the TRMM Precipitation Radar (PR). Then the characteristics of radar reflectivity and lightning flash rate are calculated in each RPF using PR and Lightning Imaging Sensor (LIS) observations. Using these RPFs, temperatures at 20, 30, and 40 dBZ radar echo tops, used as proxies of the maximum convective intensity of precipitation systems, are examined as indicators of the probability of lightning. Although 30 and 40 dBZ echo top temperatures are better indicators of the probability of lightning than the 20 dBZ echo top temperature, there is a large regional variation in the temperature thresholds, especially between land and ocean. In general, oceanic thunderstorms have higher 20 dBZ echo top and larger horizontal extent than those over land. However, radar reflectivity is more likely to exceed 30 and 40 dBZ at cold temperatures over land than over ocean. The correlations between flash rates and radar echo top temperatures, areas and volumes of radar reflectivity, and ice water contents in the mixed phase region are analyzed using RPFs with at least one flash. In agreement with previous studies, the correlations with the echo top temperatures are low, but the correlations between flash rates and areas and volumes of high radar reflectivity in the mixed phase region are much higher. There is a high correlation between the flash rates and the volumes with radar reflectivity greater than 30, 35, or 40 dBZ in the mixed phase region, but the correlation coefficient varies significantly between thunderstorms over different regions, especially between land and ocean. These results are confirmed by repeating the analysis for regions of the storms defined as convective, thus eliminating the contribution from large areas of stratiform radar echo that have much less lightning.
Escalating Coverage of Obesity in UK Newspapers: The Evolution and Framing of the “Obesity Epidemic” From 1996 to 2010
Authors: Hilton Shona , Patterson Chris , Teyhan Alison
Published: February 2012

Obesity is one of the fastest growing and most serious public health challenges facing the world in the 21st century. Correspondingly, over the past decade there has been increased interest in how the obesity epidemic has been framed by the media. This study offers the first large‐scale examination of the evolution and framing of the obesity epidemic in UK newspapers, identifying shifts in news coverage about the causal drivers of and potential solutions to the obesity epidemic. Seven UK newspapers were selected and 2,414 articles published between 1 January 1996 and 31 December 2010 were retrieved from electronic databases using keyword searches. The thematic content of articles was examined using manifest content analysis. Over the 15‐year period there was an increase in media reporting on obesity and in particular on childhood obesity. There was evidence of a trend away from a focus on individuals towards a greater level of reporting on societal solutions such as regulatory change, with the greatest shift in reporting occurring in mid‐market and serious newspapers. Given that the media have a huge influence in shaping public opinion, this shift in reporting might be an early indicator to policymakers of a growing public discourse around a need for regulatory change to tackle the obesogenic environment.
Development of compact linear accelerator in KBSI
Authors: Yoon Jang-Hee , Lee Byoung-Seob , Choi Seyong , Park Jin Yong , Ok Jung-Woo , Won Mi-Sook
Published: February 2012

The compact linear accelerator using a 28 GHz ECRIS is under construction in KBSI, South Korea. The main capability of this facility is the production of fast neurons for the neutron radiography. The designing of a superconducting magnet, microwave transmission system, beam extraction, and plasma chamber of ECRIS were finished. The nominal axial design fields of the magnets are 3.6 T at injection and 2.2 T at extraction; the nominal radial design field strength at the plasma chamber wall is 2.1 T. We already installed 10 kW, 28 GHz gyrotron, and tested a microwave power from gyrotron using a dummy load. The current status will be discussed in this paper.
New laser setup for the selective isotope production and investigation in a laser ion source at the IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron) facility
Authors: Barzakh A. E. , Fedorov D. V. , Ivanov V. S. , Molkanov P. L. , Panteleev V. N. , Volkov Yu. M.
Published: February 2012

New laser installation for the resonance ionization spectroscopy in a laser ion source and for rare isotope production has been recently put into operation at the IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron) facility (Petersburg Nuclear Physics Institute, Gatchina). This is a significant improvement of a previous target-laser ion source device of the IRIS mass-separator, working on-line with 1 GeV proton beam of PNPI (Petersburg Nuclear Physics Institute) synchrocyclotron. It makes possible for us to get the isobarically clean radioactive isotope beams of a great number of chemical elements. New laser setup provides the two- or three-resonance step ionization in the range of wavelength of 265–850 nm. The first results obtained at the laser setup for Tl isotopes are presented.
Design and investigations of the superconducting magnet system for the multipurpose superconducting electron cyclotron resonance ion source
Authors: Tinschert K. , Lang R. , Mäder J. , Roßbach J. , Spädtke P. , Komorowski P. , Meyer-Reumers M. , Krischel D. , Fischer B. , Ciavola G. , Gammino S. , Celona L.
Published: February 2012

The production of intense beams of heavy ions with electron cyclotron resonance ion sources (ECRIS) is an important request at many accelerators. According to the ECR condition and considering semi-empirical scaling laws, it is essential to increase the microwave frequency together with the magnetic flux density of the ECRIS magnet system. A useful frequency of 28 GHz, therefore, requires magnetic flux densities above 2.2 T implying the use of superconducting magnets. A cooperation of European institutions initiated a project to build a multipurpose superconducting ECRIS (MS-ECRIS) in order to achieve an increase of the performances in the order of a factor of ten. After a first design of the superconducting magnet system for the MS-ECRIS, the respective cold testing of the built magnet system reveals a lack of mechanical performance due to the strong interaction of the magnetic field of the three solenoids with the sextupole field and the magnetization of the magnetic iron collar. Comprehensive structural analysis, magnetic field calculations, and calculations of the force pattern confirm thereafter these strong interactions, especially of the iron collar with the solenoidal fields. The investigations on the structural analysis as well as suggestions for a possible mechanical design solution are given.
Performance and operation of advanced superconducting electron cyclotron resonance ion source SECRAL at 24 GHz
Authors: Zhao H. W. , Lu W. , Zhang X. Z. , Feng Y. C. , Guo J. W. , Cao Y. , Li J. Y. , Guo X. H. , Sha S. , Sun L. T. , Xie D. Z.
Published: February 2012

SECRAL (superconducting ECR ion source with advanced design in Lanzhou) ion source has been in routine operation for Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex since May 2007. To further enhance the SECRAL performance in order to satisfy the increasing demand for intensive highly charged ion beams, 3–5 kW high power 24 GHz single frequency and 24 GHz +18 GHz double frequency with an aluminum plasma chamber were tested, and some exciting results were produced with quite a few new record highly charged ion beam intensities, such as 129Xe35+ of 64 eμA, 129Xe42+ of 3 eμA, 209Bi41+ of 50 eμA, 209Bi50+ of 4.3 eμA and 209Bi54+ of 0.2 eμA. In most cases SECRAL is operated at 18 GHz to deliver highly charged heavy ion beams for the HIRFL accelerator, only for those very high charge states and very heavy ion beams such as 209Bi36+ and 209Bi41+, SECRAL has been operated at 24 GHz. The total operation beam time provided by SECRAL up to July 2011 has exceeded 7720 hours. In this paper, the latest performance, development, and operation status of SECRAL ion source are presented. The latest results and reliable long-term operation for the HIRFL accelerator have demonstrated that SECRAL performance for production of highly charged heavy ion beams remains improving at higher RF power with optimized tuning.
Ion optics of RHIC electron beam ion source
Authors: Pikin A. , Alessi J. , Beebe E. , Kponou A. , Okamura M. , Raparia D. , Ritter J. , Tan Y. , Kuznetsov G.
Published: February 2012

RHIC electron beam ion source has been commissioned to operate as a versatile ion source on RHIC injection facility supplying ion species from He to Au for Booster. Except for light gaseous elements RHIC EBIS employs ion injection from several external primary ion sources. With electrostatic optics fast switching from one ion species to another can be done on a pulse to pulse mode. The design of an ion optical structure and the results of simulations for different ion species are presented. In the choice of optical elements special attention was paid to spherical aberrations for high-current space charge dominated ion beams. The combination of a gridded lens and a magnet lens in LEBT provides flexibility of optical control for a wide range of ion species to satisfy acceptance parameters of RFQ. The results of ion transmission measurements are presented.
Intense beams from gases generated by a permanent magnet ECR ion source at PKU
Authors: Ren H. T. , Peng S. X. , Lu P. N. , Yan S. , Zhou Q. F. , Zhao J. , Yuan Z. X. , Guo Z. Y. , Chen J. E.
Published: February 2012

An electron cyclotron resonance (ECR) ion source is designed for the production of high-current ion beams of various gaseous elements. At the Peking University (PKU), the primary study is focused on developing suitable permanent magnet ECR ion sources (PMECRs) for separated function radio frequency quadrupole (SFRFQ) accelerator and for Peking University Neutron Imaging Facility. Recently, other kinds of high-intensity ion beams are required for new acceleration structure demonstration, simulation of fusion reactor material irradiation, aviation bearing modification, and other applications. So we expanded the ion beam category from O+, H+, and D+ to N+, Ar+, and He+. Up to now, about 120 mA of H+, 83 mA of D+, 50 mA of O+, 63 mA of N+, 70 mA of Ar+, and 65 mA of He+ extracted at 50 kV through a ϕ 6 mm aperture were produced by the PMECRs at PKU. Their rms emittances are less than 0.2 π mm mrad. Tungsten samples were irradiated by H+ or He+ beam extracted from this ion source and H/He holes and bubbles have been observed on the samples. A method to produce a high intensity H/He mixed beam to study synergistic effect is developed for nuclear material irradiation. To design a He+ beam injector for coupled radio frequency quadruple and SFRFQ cavity, He+ beam transmission experiments were carried out on PKU low energy beam transport test bench and the transmission was less than 50%. It indicated that some electrode modifications must be done to decrease the divergence of He+ beam.
First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABS
Authors: Thomae R. , Conradie J. , Delsink H. , Du Plessis H. , Fourie D. , Hitz D. , Klopp M. , Kohler I. , Kuechler D. , Lussi C. , McAlister R. , Ntshangase S. , Sakildien M.
Published: February 2012

iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS.
Array of 12 coils to measure the position, alignment, and sensitivity of magnetic sensors over temperature
Authors: Husstedt Hendrik , Ausserlechner Udo , Kaltenbacher Manfred
Published: February 2012

A measurement setup is presented that allows one to determine the position, alignment, and sensitivity of magnetic sensors over temperature. To this end, an array of 12 coils is used where the number of coils is larger than the number of unknowns to increase accuracy, and to ensure an adequate measurement signal for an arbitrary orientation of the magnetic sensors. With this coil array, a 3D sensing system is analyzed which is used during the testing of automotive magnetic sensors. In particular, the influence of assembly tolerances, and the variation of temperature are examined.
Random magnetization dynamics at elevated temperatures
Authors: Mayergoyz I. , Bertotti G. , Serpico C. , Liu Z. , Lee A.
Published: February 2012

Generalization of the classical Landau-Lifshitz equation for the case of magnetization dynamics at elevated temperatures is discussed. This generalization is based on the description of thermal bath effects by a jump-noise process, and it results in equations that describe magnetization dynamics when magnetization magnitude is not conserved.
Structural studies of high-Ku metastable CoPt thin films with long-range order
Authors: Yuan Fu-Te , Hsu Jen-Hwa , Lin Yi-Hung , Hsiao S. N. , Lee H. Y.
Published: February 2012

The symmetries of CoPt thin films in different phases, including disordered A1, ordered L11, and L10 were examined by making measurements along the (10.1) diffraction rod. The films were deposited by sputtering on MgO(111) substrates at different temperatures (Ta). The stacking sequence of close-packed atomic planes in 50 nm-thick samples with Ta ≥ 200 °C was identified as ABCABC, indicating that the distribution of defects in the film was random, so the symmetry was preserved with increasing Ta. In the RT-prepared film, a considerable amount of (∼62.9 vol.%) disordered CoPt with hexagonal symmetry was detected, vanishing as Ta increased. Defect-induced modification of symmetry was observed in the L11 film as its thickness was reduced to 10 nm. A pseudo-hcp component of around 7.1 vol.% was present in the film, as a result of the periodic distribution of defects. The defects in the structure may also explain the broadened magnetic alignment.
Carbon nanotube-coated silicated soft magnetic carbonyl iron microspheres and their magnetorheology
Authors: Liu Y. D. , Choi H. J.
Published: February 2012

Core-shell structured magnetic microspheres were fabricated by coating the surface of silicated soft magnetic carbonyl iron particles with multi-walled carbon nanotubes using a facile layer-by-layer method involving an alternative sequential adsorption of positive and negative polyelectrolytes. The morphology of the fabricated particles was observed by scanning electron microscopy. The magnetorheological (MR) behavior affected by the non-magnetic coatings was examined using a rotational rheometer under a controlled magnetic field. The flow curves of typical MR characteristics with improved shear stresses were observed under a range of magnetic field strengths.
Influence of ferroelectric poling induced strain on magnetic and electric properties in tetravalent cation-doped La0.9Hf0.1MnO3 films
Authors: Wu Z. P. , Wang L. , Guo E. J. , Gao J.
Published: February 2012

Electron-doped manganites La0.9Hf0.1MnO3 (LHMO) films were epitaxially grown on 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-PT) substrates. The effects of the strain induced by ferroelectric poling on the magnetic and electric properties have been investigated. The polarization of the PMN-PT crystal reduces the biaxial tensile strain in the formed LHMO layer. It results in a significant decrease in resistance and an enhancement of the phase transition temperature as well as the magnetization of the grown LHMO films. Our study shows that the strain-induced distortion of MnO6 octahedron plays an important role in impacting the properties of LHMO films.
Revised self-consistent continuum solvation in electronic-structure calculations
Authors: Andreussi Oliviero , Dabo Ismaila , Marzari Nicola
Published: February 2012

The solvation model proposed by Fattebert and Gygi [J. Comput. Chem. 23, 662 (2002)10.1002/jcc.10069] and Scherlis et al. [J. Chem. Phys. 124, 074103 (2006)10.1063/1.2168456] is reformulated, overcoming some of the numerical limitations encountered and extending its range of applicability. We first recast the problem in terms of induced polarization charges that act as a direct mapping of the self-consistent continuum dielectric; this allows to define a functional form for the dielectric that is well behaved both in the high-density region of the nuclear charges and in the low-density region where the electronic wavefunctions decay into the solvent. Second, we outline an iterative procedure to solve the Poisson equation for the quantum fragment embedded in the solvent that does not require multigrid algorithms, is trivially parallel, and can be applied to any Bravais crystallographic system. Last, we capture some of the non-electrostatic or cavitation terms via a combined use of the quantum volume and quantum surface [M. Cococcioni, F. Mauri, G. Ceder, and N. Marzari, Phys. Rev. Lett. 94, 145501 (2005)10.1103/PhysRevLett.94.145501] of the solute. The resulting self-consistent continuum solvation model provides a very effective and compact fit of computational and experimental data, whereby the static dielectric constant of the solvent and one parameter allow to fit the electrostatic energy provided by the polarizable continuum model with a mean absolute error of 0.3 kcal/mol on a set of 240 neutral solutes. Two parameters allow to fit experimental solvation energies on the same set with a mean absolute error of 1.3 kcal/mol. A detailed analysis of these results, broken down along different classes of chemical compounds, shows that several classes of organic compounds display very high accuracy, with solvation energies in error of 0.3-0.4 kcal/mol, whereby larger discrepancies are mostly limited to self-dissociating species and strong hydrogen-bond-forming compounds.
Structure and properties of metal-exchanged zeolites studied using gradient-corrected and hybrid functionals. I. Structure and energetics
Authors: Göltl Florian , Hafner Jürgen
Published: February 2012

The structural and energetic properties of purely siliceous, proton-, and Cu- and Co-exchanged chabazite have been studied using periodic density-functional (DFT) calculations with both conventional gradient-corrected exchange-correlation functionals and hybrid functionals mixing exact (i.e., Hartree-Fock) and DFT exchange. Spin-polarized and fixed-moment calculations have been performed to determine the equilibrium and excited spin-configurations of the metal-exchanged chabazites. For the purely siliceous chabazite, hybrid functionals predict a slightly more accurate cell volume and lattice geometry. For isolated Al/Si substitution sites, gradient-corrected functionals predict that the lattice distortion induced by the substitution preserves the local tetrahedral symmetry, whereas hybrid functionals lead to a distorted Al coordination with two short and two long Al-O bonds. Hybrid functionals yield a stronger cation-framework binding that conventional functionals in metal-exchanged zeolites, they favor shorter cation-oxygen bonds and eventually also a higher coordination of the cation. Both types of functionals predict the same spin in the ground-state. The structural optimization of the excited spin-states shows that the formation of a high-spin configuration leads to a strong lattice relaxation and a weaker cation-framework bonding. For both Cu- and Co-exchanged chabazite, the prediction of a preferred location of the cation in a six-membered ring of the zeolite agrees with experiment, but the energy differences between possible cation locations and the lattice distortion induced by the Al/Si substitution and the bonding of the cation depends quite significantly on the choice of the functional. All functionals predict similar energy differences for excited spin states. Spin-excitations are shown to be accompanied by significant changes in the cation coordination, which are more pronounced with hybrid functionals. The consequences of electronic spectra and chemical reactivity are analyzed in the following papers.
Channeling dynamics of relativistic-intensity laser pulses
Authors: Friou A. , Lefebvre E. , Gremillet L.
Published: February 2012

Two-dimensional particle-in-cell simulations were performed to study the channeling in long (>500μm) underdense plasmas of long duration (>10 ps), relativistic-intensity (I=1018-20 W/cm2) laser pulses. We describe five different types of channeling behaviors, and the corresponding ranges of plasmas and laser parameters are given. In all of these cases, self-corrective mechanisms come into play, which help straighten the channel provided that the laser pulse is long enough to push the plasma ahead. High-quality channels are observed when ξ=(nnc(1+a02/2)-0.5)1.22πW0λa0<0.2, where nc is the critical density, a0 is the vacuum vector potential, W0 is the waist of the laser pulse, and λ is its wavelength. We also define a method to measure the channeling velocity without ambiguity, and we establish scaling laws. It is then possible to use them to predict the channel front position in an inhomogeneous plasma, such as the coronal plasma of a fast ignition target, and to deduce the energy needed to reach the critical density. Our scaling laws indicate that the required laser energy is 50 times higher when using a laser with I=1020 W/cm2 than with I=1018 W/cm2. Our predictions are compared with a simulation of the laser propagation through a mm-long exponential plasma.
Development of tilted hexagonal platelet ZnO using atmospheric pressure chemical vapor deposition and investigation of its growth mechanism
Authors: Yoo Y. Z. , Kim S. H. , Yoon G. S. , Choi E. H. , Park J.-W. , Park J. H. , Kim B.-G. , Jung S. C. , Park B. M.
Published: February 2012

Large area ZnO films (25 × 25 cm2) grown via atmospheric pressure chemical vapor deposition (APCVD) showed unique surface morphologies of tilted hexagonal platelets. In response to the tilt angle change from 50° to 75°, haze values increased from 7% to 25%, indicating that tilt angles directly affected the light-trapping capabilities of films. These unique surfaces were created when H2O oxidizers were used, while powder-like ZnO formed when O2 or O3 oxidizers were used. Based on experimental results, corresponding density function theory, and thermodynamic calculations, the initial growth and property of APCVD for ZnO on glass were elucidated.
A pancake-shaped nano-aggregate for focusing surface plasmons
Authors: Ying Huang Shao , Cho Chew Weng , Liu Yang G. , Wu Bae-Ian , Choi H. W.
Published: February 2012

We proposed a pancake-shaped nano-aggregate that highly focuses surface plasmons. The structure is a superposition of bowtie-shaped dimers, where surface plasmons are excited, resonated with the structure, and coupled. Surface integral equation method (Poggio-Miller-Chang-Harrington-Wu-Tsai method) is used to predict the performance of the proposed structure. It is a method which can accurately calculate the near-fields of nanoparticles. Based on the numerical prediction, the proposed structure shows an electric field (E-field) enhancement of more than 400 times, which is equivalent to a Raman enhancement factor of more than 2.5e10 times. It is promising for single molecule detections using surface-enhanced Raman scattering. The physics of the proposed structure are revealed. It is useful to design nanostructures for high E-field enhancement.
Phase field simulations of stress controlling the vortex domain structures in ferroelectric nanosheets
Authors: Chen W. J. , Zheng Yue , Wang Biao
Published: February 2012

Effect of stress loads on the vortex domain structures (VDSs) in ferroelectric nanosheet has been investigated. Results of phase field simulations show that the different vortex domain structures can form in free-standing nanosheet from random perturbations. Applying stress loads on nanosheet, it is found that the domain morphology, especially the size and number of vortices, can be regularly controlled. These results indicate promising controlling the vortex domain structures in ferroelectric nanostructures by the mechanical loads.
A third-order complementary metal–oxide–semiconductor sigma-delta modulator operating between 4.2 K and 300 K
Authors: Okcan Burak , Gielen Georges , Van Hoof Chris
Published: February 2012

This paper presents a third-order switched-capacitor sigma-delta modulator implemented in a standard 0.35-μm CMOS process. It operates from 300 K down to 4.2 K, achieving 70.8 dB signal-to-noise-plus-distortion ratio (SNDR) in a signal bandwidth of 5 kHz with a sampling frequency of 500 kHz at 300 K. The modulator utilizes an operational transconductance amplifier in its loop filter, whose architecture has been optimized in order to eliminate the cryogenic anomalies below the freeze-out temperature. At 4.2 K, the modulator achieves 67.7 dB SNDR consuming 21.17 μA current from a 3.3 V supply.
3D mechanical measurements with an atomic force microscope on 1D structures
Authors: Kallesøe Christian , Larsen Martin B. , Bøggild Peter , Mølhave Kristian
Published: February 2012

We have developed a simple method to characterize the mechanical properties of three dimensional nanostructures, such as nanorods standing up from a substrate. With an atomic force microscope the cantilever probe is used to deflect a horizontally aligned nanorod at different positions along the nanorod, using the apex of the cantilever itself rather than the tip normally used for probing surfaces. This enables accurate determination of nanostructures’ spring constant. From these measurements, Young's modulus is found on many individual nanorods with different geometrical and material structures in a short time. Based on this method Young's modulus of carbon nanofibers and epitaxial grown III-V nanowires has been determined.
Asymmetric switching behavior in perpendicularly magnetized spin-valve nanopillars due to the polarizer dipole field
Authors: Gopman D. B. , Bedau D. , Mangin S. , Lambert C. H. , Fullerton E. E. , Katine J. A. , Kent A. D.
Published: February 2012

We report the free layer switching field distributions of spin-valve nanopillars with perpendicular magnetization. While the distributions are consistent with a thermal activation model, they show a strong asymmetry between the parallel to antiparallel and the reverse transition, with energy barriers more than 50% higher for the parallel to antiparallel transitions. The inhomogeneous dipolar field from the polarizer is demonstrated to be at the origin of this symmetry breaking. Interestingly, the symmetry is restored for devices with a lithographically defined notch pair removed from the midpoint of the pillar cross-section along the ellipse long axis. These results have important implications for the thermal stability of perpendicular magnetized magnetic random access memory bit cells.
High temperature annealing of n-type 4H-SiC: Impact on intrinsic defects and carrier lifetime
Authors: Zippelius Bernd , Suda Jun , Kimoto Tsunenobu
Published: February 2012

In this paper, the impact of high-temperature annealing of 4H silicon carbide (SiC) on the formation of intrinsic defects, such as Z1/2 and EH6/7, and on carrier lifetimes was studied. Four nitrogen-doped epitaxial layers with various initial concentrations of the Z1/2- and EH6/7-centers (1011-1014cm-3) were investigated by means of deep level transient spectroscopy and microwave photoconductance decay. It turned out that the high-temperature annealing leads to a monotone increase of the Z1/2- and EH6/7-concentration starting at temperatures between 1600 °C and 1750 °C, depending on the initial defect concentration. In the case of samples with high initial defect concentration (1014cm-3) a distinct decrease in Z1/2- and EH6/7-concentration in the temperature range from 1600 °C to 1750 °C was observed, being consistent with previous reports. For higher annealing temperatures (Tanneal≥1750 ∘C), the defect concentration is independent of the samples’ initial values. As a consequence, beside the growth conditions, such as C/Si ratio, the thermal post-growth processing has a severe impact on carrier lifetimes, which are strongly reduced for samples annealed at high temperatures.
Rational solutions of the Noumi and Yamada system of type $A_4^{(1)}$A4(1)
Authors: Matsuda Kazuhide
Published: February 2012

We completely classify the rational solutions of the Noumi and Yamada system of type $A_4^{(1)}$A4(1), which is a generalization of the fourth Painlevé equation. The rational solutions are classified to three by the Bäcklund transformation group.
Electronic and magnetic properties of substitutionally Fe-, Co-, and Ni-doped BC3 honeycomb structure
Authors: Lin Xianqing , Ni Jun
Published: February 2012

First-principles calculations have been performed to investigate the electronic and magnetic properties of BC3 honeycomb structure (2D BC3) substitutionally doped with Fe, Co, and Ni. 2D BC3 is a semiconductor with a mediate bandgap. When substituting for B, the Fe, Co, and Ni impurity atoms exhibit distinct electronic and magnetic behavior. Substitution of Fe for B transforms 2D BC3 into a magnetic semiconductor with only localized bands of minority-spin in the bandgap. The system doped with Co is a nonmagnetic semiconductor. The doping of Ni introduces electrons into the conduction bands of 2D BC3 and thus leads to a semiconductor-metal transition. The substitutions of Fe, Co, and Ni for C maintain the semiconducting nature of 2D BC3 with only Co presenting a localized magnetic moment. The rich electronic and magnetic properties of 2D BC3 with substitutional doping of 3d transition metal atoms suggest potential applications of the system in electronic and spintronic devices.
Potential role of renewable energy in water desalination in Australia
Authors: Rowlinson Ben , Gunasekera Don , Troccoli Alberto
Published: February 2012

With projected increases in population and urbanisation in Australia, the sustainable supply of water and energy over the medium to long term will be an important challenge. In this context, meeting a part of the growing demand for urban water may involve reliance upon desalinated water in the future. Moreover, the feasibility and viability of renewable energy sources for water desalination will be of policy importance, particularly in a potentially low carbon Australian economy. In this article, we analyse the potential applicability of solar and wind energy to provide power for water desalination. In two illustrative examples, we assess the feasibility of supplying 3% of Sydney’s projected total water consumption (supplied at an average rate of 24.7 Gl/yr) and 5% of Sydney’s projected water consumption (supplied at an average rate of 32.7 Gl/yr) over a 15-yr period (2011–2025) using a photovoltaic (PV) solar powered (130 MW) and a hybrid (PV solar and wind energy) powered (205 MW) reverse osmosis (RO) desalination plants, respectively. In addition to supplying cleaner energy, the renewable energy sources considered in this article have additional cost advantages in the presence of a carbon penalty. For example, at hypothetical carbon penalty rates of $20/tCO2 and $30/tCO2, the estimated cost savings—in net present value (NPV) terms assuming a discount rate of 4.2%—of the PV solar (hybrid) plant will amount to around be $18.7 m ($25.2 m) and $28.0 m ($37.9 m), respectively, over the 15-yr period, relative to a situation where the desalination plant is instead being powered by black coal. Under a discount rate of 8.4%, the cost savings of the PV solar (hybrid) plant associated with carbon penalty rates of $20/tCO2 and $30/tCO2 are estimated to be around $12.8 m ($17.6 m) and $19.2 m ($26.4 m), respectively, in NPV terms. Our analysis also shows that in addition to providing the required power supply for the illustrative desalination plants, the renewable energy supply sources analysed here would produce excess electricity that could be sold to a nearby grid. Consequently, assuming a wholesale electricity price of $36.74/MWh, the PV solar plant and the hybrid renewable plant are estimated to have the capacity to earn around $63.9 million and $110.0 million in NPV terms, respectively, over the 15-yr period, through excess electricity sales. Under a discount rate of 8.4%, the value of the excess electricity sales of the PV solar plant and the hybrid renewable plant are estimated to be around $54.5 million and $91.7 million, respectively, in NPV terms.
Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced plasmas
Authors: Crank M. , Harilal S. S. , Hassan S. M. , Hassanein A.
Published: February 2012

We investigated the effects of laser excitation wavelength on water-window emission lines of laser-produced boron-nitride plasmas. Plasmas are produced by focusing 1064 nm and harmonically generated 532 and 266 nm radiation from a Nd:YAG laser on BN target in vacuum. Soft x-ray emission lines in the water-window region are recorded using a grazing-incidence spectrograph. Filtered photodiodes are used to obtain complementary data for water-window emission intensity and angular dependence. Spectral emission intensity changes in nitrogen Ly-α and He-α are used to show how laser wavelength affects emission. Our results show that the relative intensity of spectral lines is laser wavelength dependent, with the ratio of Ly-α to He-α emission intensity decreasing as laser wavelength is shortened. Filtered photodiode measurements of angular dependence showed that 266 and 532 nm laser wavelengths produce uniform emission.