bluuebunny/crossref_metadata_2025 huggingface dataset:
Becoming Brazilian to Be Japanese: Emigrant Assimilation, Cultural Anthropology, and National Identity
Authors: Kingsberg Miriam
Published: December 2013

Assimilation makes new members of a group by changing particular characteristics of non-members to reflect the fundamentals of collective belonging. Gaining the qualities for inclusion in one community typically involves losing at least some features that confer acceptance in another. However, scholars have generally not acknowledged assimilation as a process of loss. In part, this gap bespeaks a larger tendency to overlook the influence of emigration on national identity in population-exporting states (compared to the vast literature on immigration and national identity in population-receiving countries). This article analyzes discourses of assimilation concerning Japanese emigrants as a case study of how the ways in which members are understood to leave the national community delimits the bases of belonging for those who remain. Historically, Japanese ideologies of assimilation have been most contested in Brazil, where the largest Japanese diaspora in the West sought to reconcile patriotism and the expectations of the Japanese government with local nation-building agendas. After World War II, many emigrants and their descendants in Brazil refused to acknowledge Japan's surrender. This crisis inspired the first study of the Japanese diaspora ever conducted by a Japan-based social scientist. Izumi Seiichi's work in cultural anthropology helped to build Japan's new identity as a “peace state.” Subsequent generations of Japanese scholars continued to study the assimilation of the diaspora, recategorized as “Nikkei,” as a foil for “Japaneseness.” Their ethnic conception of national membership remains influential today, even as Japan transitions from a population exporter to a land of immigrants, including the Nikkei.
Two “Waves” of Guerrilla-Movement Organizing in Latin America, 1956–1990
Authors: Wickham-Crowley Timothy
Published: December 2013

The organization of revolutionary guerrilla movements by the Latin American left came in two largely discrete waves. The first was occasioned by the success of the Cuban 26th of July movement against the late 1950s regime of Fulgencio Batista. Within less than a year it was triggering imitative efforts across Latin America via the cultural diffusion of its “focomodel” both indirectly and directly, as indicated by the timing, internal movement evidence, direct training, and other sources concerning the 1960s guerrilla movements. A clear dampening of such efforts followed upon the multiple failures of the imitators, the late 1967 death of Che Guevara in Bolivia, the withdrawal of Soviet-line communists in Latin America from their previous support for insurgency, and finally Cuba's own rapprochement with the USSR. At this juncture, “surviving” movements from the earlier period were few—notably in Colombia, less true in Guatemala and Nicaragua—but a second, narrower cluster of far larger, more intensive and active movements developed by the later 1970s. Such strong survivors or newcomers can be best understood, not as imitations of Cuba 1959, but via their new strategies of long-term patient organizing and by the types of “closed regimes” they were confronting in the 1970s–1980s. They, too, then mostly faded away in the face of national-level experiences of massive military repression or ever-more-competitive electoral democracies.
Semi-Normal Log Centres and Deformations of Pairs
Authors: Kollár János
Published: December 2013

We show that some of the properties of log canonical centres of a log canonical pair also hold for certain subvarieties that are close to being a log canonical centre. As a consequence, we obtain that, in working with deformations of pairs where all the coefficients of the boundary divisor are bigger than ½, embedded points never appear on the boundary divisor.
“We Act as Their Agents” and the Prohibition of Judgment by Laymen: A Discussion of Babylonian Talmud Gittin 88b
Authors: Radzyner Amihai
Published: December 2013

A sugya just a few lines long in the Babylonian Talmud, Gittin 88b, had enormous influence on the development of Jewish law in the area of the authority to pass judgment given to rabbinical courts in our day. According to the simple, commonly accepted understanding of this sugya, the Tannaim ruled that the Torah forbade men who had not received ordination to act as judges, and as a result, the judges in Babylonia were permitted to adjudicate, of necessity, only as agents of the judges of Palestine (שליחותייהו קא עבדינן, we act as their agents). The article reexamines these positions. The first part suggests two new ways to understand the essence of the agency of which R. Joseph spoke in the sugya. The second part of the article reexamines the source of the prohibition, to the extent that it exists, against adjudication by laymen.
Literary Canonization at Work: The Authority of Aggadic Midrash and the Evolution of Havdalah Poetry in the Genizah
Authors: Lavee Moshe
Published: December 2013

Applying a social interaction approach to the study of the reception of different literary genres, this article focuses on an unnoticed Judeo-Arabic Genizah fragment whose contents deal with the relative cultural value of midrash andpiyyutin medieval Mediterranean society. The fragment describes a debate concerning the identity of Elijah and his connection to the zealous act of Phineas. The debate, which probably took place in the early thirteenth century in Fustat, occurred in reaction to a synagogue performance of Havdalah liturgical poetry. The arguments for and against the poems were based on aggadic traditions. A survey of relevantpiyyutimreveals that this debated motif was indeed subject to variations and alterations. A similar development can be traced in the evolution of another Havdalahpiyyutcomposed by Rabbi Yehudah Ha-Levi. The fluidity of the poetic texts likely reflects the same literary hierarchy presented in the events recorded in the Genizah fragment (and at the same time reinforced by them): a growing appreciation of the authority of aggadic midrash, alongside the perception of the Havdalahpiyyutas creative performance, and not as an authoritative source of knowledge.
Renaissance in the Graveyard: The Hebrew Tombstones of Padua and Ashkenazic Acculturation in Sixteenth-Century Italy
Authors: Malkiel David
Published: December 2013

The acculturation Ashkenazic Jews in Italy is the focus of the present discussion. By 1500 Jews had been living in Padua for centuries, but their cemeteries were destroyed in the 1509. Four cemeteries remained with over 1200 inscriptions between 1530–1860. The literary features of the inscriptions indicate a shift from a preference for epitaphs written in prose, like those of medieval Germany, to epitaphs in the form of Italian Jewry's occasional poetry. The art and architecture of the tombstones are part and parcel of the Renaissance ambient, with the portals and heraldry characteristic of Palladian edifices. The lettering, too, presents a shift from the constituency's medieval Ashkenazic origins to its Italian setting. These developments are situated in the broader context of Italian Jewish art and architecture, while the literary innovations are shown to reflect the revival of the epigram among poets of the Italian Renaissance.
Assessment of heart rate variability in breath holding children by 24 hour Holter monitoring
Authors: Yilmaz Osman , Ciftel Murat , Ozturk Kezban , Kilic Omer , Kahveci Hasan , Laloğlu Fuat , Ceylan Ozben
Published: December 2013

Purpose:Previous studies have shown that the underlying pathophysiologic mechanism in children with breath holding may be generalised autonomic dysregulation. Thus, we performed cardiac rhythm and heart rate variability analyses using 24-hour Holter monitoring to evaluate the cardiac effects of autonomic dysregulation in children with breath-holding spells.Methods:We performed cardiac rhythm and heart rate analyses using 24-hour Holter monitors to evaluate the cardiac effects of autonomic dysregulation in children during a breath-holding spell. Our study group consisted of 68 children with breath-holding spells – 56 cyanotic type and 12 pallid type – and 39 healthy controls.Results:Clinical and heart rate variability results were compared between each spell type – cyanotic or pallid – and the control group; significant differences (p<0.05) in standard deviation of all NN intervals, mean of the standard deviations of all NN intervals for all 5-minute segments, percentage of differences between adjacent RR intervals >50 ms, and square root of the mean of the sum of squares of the differences between adjacent NN intervals values were found between the pallid and cyanotic groups.Conclusions:Holter monitoring for 24 hours and heart rate variability parameters, particularly in children with pallid spells, are crucial for evaluation of cardiac rhythm changes.
Monotheism the Zoroastrian Way
Authors: HINTZE ALMUT
Published: December 2013

This article examines seemingly monotheistic, polytheistic and dualistic features of Zoroastrianism from the point of view of the Zoroastrian creation myth. Exploring the personality of the principal deity, Ahura Mazdā, the origin of the spiritual and material worlds and the worship of the Yazatas, it is argued that Zoroastrianism has its own particular form of monotheism.
INFLATION IN THE G7: MIND THE GAP(S)?
Authors: Morley James , Piger Jeremy , Rasche Robert
Published: December 2013

We investigate the importance of trend inflation and the real-activity gap in explaining inflation in G7 countries since 1960. Our analysis is based on a bivariate unobserved components model of inflation and unemployment in which inflation is decomposed into a stochastic trend and a transitory component. As in recent implementations of the New Keynesian Phillips Curve, it is the transitory component of inflation, or “inflation gap,” that is driven by the real-activity gap, which we measure as the deviation of unemployment from its natural rate. We find that both trend inflation and the inflation gap have been consistent and substantial determinants of inflation at business cycle horizons for all G7 countries since 1960. Also, the real-activity gap explains a large fraction of the variation in the inflation gap for each country. These results provide empirical support for the New Keynesian Phillips Curve augmented with trend inflation.
Zusammenhänge zwischen Ekelempfindlichkeit, Ekelsensitivität und hypochondrischen Merkmalen
Authors: Schwind Julia , Rohrmann Sonja , Bechtoldt Myriam , Weck Florian
Published: December 2013

Theoretischer Hintergrund: Es gibt Hinweise, dass Ekelempfindlichkeit (Neigung, mit Ekel zu reagieren) und Ekelsensitivität (Neigung, Ekelempfindungen negativ zu bewerten) eine Rolle bei der Entstehung und Aufrechterhaltung der Hypochondrie spielen. Fragestellung: Besteht ein Zusammenhang zwischen Ekelempfindlichkeit bzw. Ekelsensitivität und hypochondrischen Merkmalen? Bleiben diese Zusammenhänge bei statistischer Kontrolle anderer Persönlichkeitseigenschaften bestehen? Methodik: Sechsundvierzig Probandinnen bearbeiteten folgende Fragebögen: Whiteley-Index (hypochondrische Merkmale), Fragebogen zur Erfassung der Ekelempfindlichkeit, Skala zur Erfassung der Ekelsensitivität, Angst-Sensitivitäts-Index, State-Trait-Angst-Depressions-Inventar (Ängstlichkeit). Ergebnisse: Es zeigten sich jeweils positive Zusammenhänge zwischen Ekelempfindlichkeit bzw. Ekelsensitivität und Krankheitsängsten. Auch nach Kontrolle des Lebensalters, Angstsensitivität und Ängstlichkeit konnten beide Ekeldomänen zusätzlich 12 % der Varianz von Krankheitsängsten aufklären. Schlussfolgerung: Die Bedeutung von Ekel für hypochondrische Merkmale erscheint größer als bisher angenommen.
Alltag des Krieges und Transzendenz von Liebe und Ehe
Authors: Becker-Glauch Wulf
Published: December 2013

In eine künstlerisch orientierte Lebensgeschichte kam der 2. Weltkrieg. Das gilt für viele Lebensgeschichten. Bei Reinhard durften wir erfahren, daß er daraus eine „Landschaft der Herzen” schuf, hinter der Elternhaus und Schule und vor allem aber seine Persönlichkeit standen, der es in den Wirren des Krieges um inneren und äußeren Frieden aus religiöser Quelle und in transzendentaler („himmelwärtiger”) Ausrichtung ging. Im Schutz und Dienst der Kunst führte ihn der Weg seit 1937 vom Ich zum Du seiner Partnerin und Frau Irmgard, wie der hier in zwei Gedichten von 1940 und 1943 seinen Ausdruck findet. „Für Irmgard zum Geburtstag” (Nov. 43) leitet mit 6 Teilen zu 4 Strophen aus dem „Lichtkreis” einer Kerze durch die Nacht der Trennung und mündet in den „festlichen Anfang” eines Sonnenaufgangs. „Nicht fehle, / Gewinnt nun der Tag die Gewalt!”.
Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation
Authors: Yakimov Michail M. , La Cono Violetta , Slepak Vladlen Z. , La Spada Gina , Arcadi Erika , Messina Enzo , Borghini Mireno , Monticelli Luis S. , Rojo David , Barbas Coral , Golyshina Olga V. , Ferrer Manuel , Golyshin Peter N. , Giuliano Laura
Published: December 2013

Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [14C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life.
Simultaneous quantitative determination of major plant hormones in pear flowers and fruit by UPLC/ESI-MS/MS
Authors: Niu Qingfeng , Zong Yu , Qian Minjie , Yang Fengxia , Teng Yuanwen
Published: December 2013

We have developed and established a novel method to quantify four distinct endogenous hormones through UPLC/ESI-MS/MS, which achieves higher throughput screening and improved resolution than HPLC or HPLC/ESI-MS/MS.
Template-free synthesis of uniform mesoporous SnO2 nanospheres for efficient phosphopeptide enrichment
Authors: Li Liping , Chen Shuai , Xu Linnan , Bai Yu , Nie Zongxiu , Liu Huwei , Qi Limin
Published: December 2013

Mesoporous SnO2 nanospheres were prepared via a one-step and template-free method and excellent enrichment performance was achieved in their applications for phosphopeptide enrichment.
Ionospheric effects on synthetic aperture radar (SAR) clutter statistics
Authors: Belcher David P. , Cannon Paul S.
Published: December 2013

Low‐frequency space‐based synthetic aperture radar (SAR) is an ideal sensor for measuring forest biomass, but can suffer from ionospheric effects. The variation in total electron content (TEC), originating from ionospheric turbulence, causes the along track point spread function (PSF) to degrade in a manner which depends on ionospheric conditions. In this study, the effect of this PSF on the single point statistics (probability density function) and two point statistics (autocorrelation function (ACF)) is derived. It is shown that the K‐distribution order parameter is directly proportional to the ionospheric turbulence, as quantified by CkL. The complex ACF is a measure of amplitude scintillation, and the intensity ACF is a measure of both the order parameter and the terrain correlation length. A simulation is performed which clearly shows that measuring the order parameter ratio between ionospherically disturbed and undisturbed images is a measure of CkL. This measure can be used two orders of magnitude below the point where the ionosphere causes defocusing of the SAR image. It is concluded that the usefulness of this new measure can only be verified by experimental data since the temporal stability of the underlying order parameter is unknown.
Coherent structures and the k−1 spectral behaviour
Authors: Calaf M. , Hultmark M. , Oldroyd H. J. , Simeonov V. , Parlange M. B.
Published: December 2013

Here we present unique evidence of a k−1 scaling behaviour in the atmospheric boundary layer and its connection to large scale coherent structures within the boundary layer. Wind lidar measurements were conducted above a lake under cold atmospheric conditions. The large coherent structures could be visually observed over Lake Geneva in Switzerland when cold air met the relatively warm water. Proper orthogonal decomposition of the experimental data acquired with the wind lidar clearly reveals coherent oscillations of both the fluctuating velocity field and the water aerosol field over the surface of the lake. Precise identification of the large coherent structures propagating in the flow allows for detailed analysis of their contribution to the total spectral budget. Additionally, it is shown that the experimental data agree well with recent theoretical predictions.
Fabrication of nanopores in a graphene sheet with heavy ions: A molecular dynamics study
Authors: Li Weisen , Liang Li , Zhao Shijun , Zhang Shuo , Xue Jianming
Published: December 2013

Molecular dynamics simulations were performed to study the formation process of nanopores in a suspended graphene sheet irradiated by using energetic ions though a mask. By controlling the ion parameters including mass, energy, and incident angle, different kinds of topography were observed in the graphene sheet. Net-like defective structures with carbon atom chains can be formed at low ion fluences, which provide the possibility to functionalize the irradiated sample with subsequent chemical methods; finally a perfect nanopore with smooth edge appears when the ion fluence is high enough. We found that the dependence of ion damage efficiency on ion fluence, energy, and incident angle are different from that predicted by the semi-empirical model based on the binary-collision approximation, which results from the special structure of graphene. Our results demonstrate that it is feasible to fabricate controlled nanopores/nanostructures in graphene via heavy ion irradiation.
Combinatorial theory of the semiclassical evaluation of transport moments II: Algorithmic approach for moment generating functions
Authors: Berkolaiko G. , Kuipers J.
Published: December 2013

Electronic transport through chaotic quantum dots exhibits universal behaviour which can be understood through the semiclassical approximation. Within the approximation, calculation of transport moments reduces to codifying classical correlations between scattering trajectories. These can be represented as ribbon graphs and we develop an algorithmic combinatorial method to generate all such graphs with a given genus. This provides an expansion of the linear transport moments for systems both with and without time reversal symmetry. The computational implementation is then able to progress several orders further than previous semiclassical formulae as well as those derived from an asymptotic expansion of random matrix results. The patterns observed also suggest a general form for the higher orders.
Comparison of several classical density functional theories for the adsorption of flexible chain molecules into cylindrical nanopores
Authors: Hlushak S. P. , Cummings P. T. , McCabe C.
Published: December 2013

Adsorption of flexible oligomers into narrow cylindrical pores has been studied by means of several versions of classical density functional theory (CDFT) and Monte Carlo simulation. The adsorption process is interesting to study due to the competition between the entropic depletion of oligomers from the pores and the wall–oligomer attraction. It is also challenging to describe using current CDFTs, which tend to overestimate the amount of the adsorbed fluid. From a comparison of several different CDFT approaches, we find that this is due to the assumption of ideal or freely jointed chain conformations. Moreover, it is demonstrated that it is impossible to obtain a reasonable description of the adsorption isotherms without taking into account accurate contact values in the distribution functions describing the structure of the reference monomer fluid. At low densities, more accurate result are obtained in comparison with Monte Carlo simulation data when accurate contact values are incorporated into the theory rather than the more commonly used hard-sphere contact value. However, even the CDFT with accurate contact values still overestimates the amount of the adsorbed fluid due to the ideal or freely jointed chain approximation, used for the description of chain conformations in most CDFT approaches. We find that significant improvement can achieved by employing self-consistent field theory, which samples self-avoiding chain conformations and decreases the number of possible chain conformations, and, consequently, the amount of the adsorbed fluid.
Simulation optimization of spherical non-polar guest recognition by deep-cavity cavitands
Authors: Wanjari Piyush P. , Gibb Bruce C. , Ashbaugh Henry S.
Published: December 2013

Biomimetic deep-cavity cavitand hosts possess unique recognition and encapsulation properties that make them capable of selectively binding a range of non-polar guests within their hydrophobic pocket. Adamantane based derivatives which snuggly fit within the pocket of octa-acid deep cavity cavitands exhibit some of the strongest host binding. Here we explore the roles of guest size and attractiveness on optimizing guest binding to form 1:1 complexes with octa-acid cavitands in water. Specifically we simulate the water-mediated interactions of the cavitand with adamantane and a range of simple Lennard-Jones guests of varying diameter and attractive well-depth. Initial simulations performed with methane indicate hydrated methanes preferentially reside within the host pocket, although these guests frequently trade places with water and other methanes in bulk solution. The interaction strength of hydrophobic guests increases with increasing size from sizes slightly smaller than methane to Lennard-Jones guests comparable in size to adamantane. Over this guest size range the preferential guest binding location migrates from the bottom of the host pocket upwards. For guests larger than adamantane, however, binding becomes less favorable as the minimum in the potential-of-mean force shifts to the cavitand face around the portal. For a fixed guest diameter, the Lennard-Jones well-depth is found to systematically shift the guest-host potential-of-mean force to lower free energies, however, the optimal guest size is found to be insensitive to increasing well-depth. Ultimately our simulations show that adamantane lies within the optimal range of guest sizes with significant attractive interactions to match the most tightly bound Lennard-Jones guests studied.
Imaging photoelectron circular dichroism of chiral molecules by femtosecond multiphoton coincidence detection
Authors: Lehmann C. Stefan , Ram N. Bhargava , Powis Ivan , Janssen Maurice H. M.
Published: December 2013

Here, we provide a detailed account of novel experiments employing electron-ion coincidence imaging to discriminate chiral molecules. The full three-dimensional angular scattering distribution of electrons is measured after photoexcitation with either left or right circular polarized light. The experiment is performed using a simplified photoelectron-photoion coincidence imaging setup employing only a single particle imaging detector. Results are reported applying this technique to enantiomers of the chiral molecule camphor after three-photon ionization by circularly polarized femtosecond laser pulses at 400 nm and 380 nm. The electron-ion coincidence imaging provides the photoelectron spectrum of mass-selected ions that are observed in the time-of-flight mass spectra. The coincident photoelectron spectra of the parent camphor ion and the various fragment ions are the same, so it can be concluded that fragmentation of camphor happens after ionization. We discuss the forward-backward asymmetry in the photoelectron angular distribution which is expressed in Legendre polynomials with moments up to order six. Furthermore, we present a method, similar to one-photon electron circular dichroism, to quantify the strength of the chiral electron asymmetry in a single parameter. The circular dichroism in the photoelectron angular distribution of camphor is measured to be 8% at 400 nm. The electron circular dichroism using femtosecond multiphoton excitation is of opposite sign and about 60% larger than the electron dichroism observed before in near-threshold one-photon ionization with synchrotron excitation. We interpret our multiphoton ionization as being resonant at the two-photon level with the 3s and 3p Rydberg states of camphor. Theoretical calculations are presented that model the photoelectron angular distribution from a prealigned camphor molecule using density functional theory and continuum multiple scattering X alpha photoelectron scattering calculations. Qualitative agreement is observed between the experimental results and the theoretical calculations of the Legendre moments representing the angular distribution for the two enantiomers. The electron-ion coincidence technique using multiphoton ionization opens new directions in table-top analytical mass-spectrometric applications of mixtures of chiral molecules.
Reaction surface approach to multimode vibronic coupling problems: General framework and application to furan
Authors: Gromov E. V. , Reddy V. Sivaranjana , Gatti F. , Köppel H.
Published: December 2013

A new general framework for treating the dynamics on intersecting multidimensional potential energy surfaces is presented. It rests on a sub-division of the nuclear coordinates into different classes, one of primary importance with large-amplitude displacements during the process of interest and another one with smaller displacements, thus permitting a more approximate description. The latter are treated within the well-known linear + quadratic vibronic coupling scheme, where, however, the expansion “coefficients” are general functions of the “primary” coordinates. This may be augmented by an effective-mode approach for further degrees of freedom acting as an environment for the dynamics of the original modes. Following the general considerations, the approach is applied to the nonadiabatic photodynamics of furan and is shown to allow for an eight-dimensional quantum treatment, of higher dimension than was possible so far. The influence of the various degrees of freedom on the dynamics and lifetime of furan due to nonadiabatic ring-opening is discussed.
Chemical composition and temperature dependent performance of ZnO-thin film transistors deposited by pulsed and continuous spray pyrolysis
Authors: Ortel Marlis , Balster Torsten , Wagner Veit
Published: December 2013

Zinc oxide thin film transistors (TFTs) deposited by continuous and pulsed spray pyrolysis were investigated to analyze process kinetics which make reduction of process temperature possible. Thus, fluid mechanics, chemical composition, electrical performance, and deposition and annealing temperature were systematically analyzed. It was found that ZnO layers continuously deposited at 360 °C contained zinc oxynitrides, CO3, and hydro carbonate groups from pyrolysis of basic zinc acetate. Statistically, every second wurtzite ZnO unit cell contained an impurity atom. The purity and performance of the ZnO-TFTs increased systematically with increasing deposition temperature due to an improved oxidation processes. At 500 °C the zinc to oxygen ratio exceeded a high value of 0.96. Additionally, the ZnO film was not found to be in a stabilized state after deposition even at high temperatures. Introducing additional subsequent annealing steps stabilizes the film and allows the reduction of the overall thermal stress to the substrate. Further improvement of device characteristics was obtained by pulsed deposition which allowed a more effective transport of the by-products and oxygen. A significant reduction of the deposition temperature by 140 °C was achieved compared to the same performance as in continuous deposition mode. The trap density close to the Fermi energy could be reduced by a factor of two to 4 × 1017 eV−1 cm−3 due to the optimized combustion process on the surface. The optimization of the deposition processes made the fabrication of TFTs with excellent performance possible. The mobility was high and exceeded 12 cm2/V s, the subthreshold slope was 0.3 V dec−1, and an on-set close to the ideal value of 0 V was achieved.
Response of LaBr3(Ce) scintillators to 2.5 MeV fusion neutrons
Authors: Cazzaniga C. , Nocente M. , Tardocchi M. , Croci G. , Giacomelli L. , Angelone M. , Pillon M. , Villari S. , Weller A. , Petrizzi L. , Gorini G. ,   ASDEX Upgrade Team,   JET-EFDA Contributors
Published: December 2013

Measurements of the response of LaBr3(Ce) to 2.5 MeV neutrons have been carried out at the Frascati Neutron Generator and at tokamak facilities with deuterium plasmas. The observed spectrum has been interpreted by means of a Monte Carlo model. It is found that the main contributor to the measured response is neutron inelastic scattering on 79Br, 81Br, and 139La. An extrapolation of the count rate response to 14 MeV neutrons from deuterium-tritium plasmas is also presented. The results are of relevance for the design of γ-ray diagnostics of fusion burning plasmas.
Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions
Authors: Valerio-Lizarraga Cristhian A. , Lallement Jean-Baptiste , Leon-Monzon Ildefonso , Lettry Jacques , Midttun Øystein , Scrivens Richard
Published: December 2013

The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H− beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.
Anomalous polarization in the antiferroelectric-ferroelectric phase coexistence state in PbZrO3-Bi(Mg1/2Ti1/2)O3
Authors: Vadlamani Bhaskar Sravan , V. Lalitha K. , Ranjan Rajeev
Published: December 2013

The ferroelectric system (1−x)PbZrO3-(x)Bi(Mg1/2Ti1/2)O3 has been investigated as a function of composition, temperature, and electric field by x-ray powder diffraction, dielectric, and ferroelectric measurements. Within the solubility limit (x ∼ 0.25), the system evolves from an orthorhombic-antiferroelectric to rhombohedral-ferroelectric state through a phase coexistence region. The highest polarization was found not for the composition exhibiting a pure ferroelectric state, but for a composition x = 0.15 exhibiting ferroelectric + antiferroelectric phase coexistence close to the rhombohedral phase boundary. Electric poling of the equilibrium two-phase state led to irreversible enhancement in the rhombohedral phase fraction suggesting that the enhanced polarization is related to the enhanced polarizability of the lattice due to first order criticality as in ferroelectric-ferroelectric morphotropic phase boundary systems.
Entangled polymer chain melts: Orientation and deformation dependent tube confinement and interchain entanglement elasticity
Authors: Sussman Daniel M. , Schweizer Kenneth S.
Published: December 2013

The phenomenological reptation-tube model is based on a single chain perspective and was originally proposed to explain the remarkable viscoelastic properties of dense entangled polymer liquids. However, simulations over the last two decades have revealed a fundamental tension in the model: it assumes that bonded, single-chain backbone stresses are the sole polymer contribution to the slowly relaxing component of stress storage and elasticity, but mounting evidence suggests that at the local level of forces it is interchain contributions that dominate, as in simple liquids. Here we show that based on a chain model constructed at the level of self-consistently determined primitive paths, an explicit force-level treatment of the correlated intermolecular contributions to stress that arise from chain uncrossability can essentially quantitatively predict the entanglement plateau modulus associated with the soft rubbery response of polymer liquids. Analogies to transient localization and elasticity in glass-forming liquids are identified. Predictions for the effect of macroscopic deformation and anisotropic orientational order on the tube diameter are also made. Based on the interchain stress perspective the theory reproduces some aspects of the rheological response to shear and extensional deformations associated with the single chain tube model.
Surface induced nucleation of a Lennard-Jones system on an implicit surface at sub-freezing temperatures: A comparison with the classical nucleation theory
Authors: Loeffler Troy D. , Chen Bin
Published: December 2013

The aggregation-volume-bias Monte Carlo method was employed to study surface-induced nucleation of Lennard-Jonesium on an implicit surface below the melting point. It was found that surfaces catalyze not only the formation of the droplets (where the nucleation free energy barriers were shown to decrease with increasing surface interaction strength), but also the transition of these droplets into crystal structures due to the surface-induced layering effects. However, this only occurs under suitable interaction strength. When surface attraction is too strong, crystallization is actually inhibited due to the spread of the particles across the surface and corresponding formation of two-dimensional clusters. The simulation results were also used to examine the bulk-droplet based classical nucleation theory for surface-induced nucleation, particularly the additional contact angle term used to describe both the nucleation free energy barrier heights and the critical cluster sizes compared to its homogeneous nucleation formalism. Similar to what has been found previously for homogeneous nucleation, the theory does poorly toward the high-supersaturation region when the critical clusters are small and fractal, but the theoretical predictions on both barrier heights and critical cluster sizes improve rapidly with the decrease of the supersaturation.
Plasma response to electron energy filter in large volume plasma device
Authors: Sanyasi A. K. , Awasthi L. M. , Mattoo S. K. , Srivastava P. K. , Singh S. K. , Singh R. , Kaw P. K.
Published: December 2013

An electron energy filter (EEF) is embedded in the Large Volume Plasma Device plasma for carrying out studies on excitation of plasma turbulence by a gradient in electron temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the plasma to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in plasma regions with different characteristics, including a plasma region free from energetic electrons, suitable for the study of ETG turbulence. Specifically, we report that localized structures of plasma density, potential, electron temperature, and plasma turbulence are excited in the EEF plasma. It is shown that structures of electron temperature and potential are created due to energy dependence of the electron transport in the filter region. On the other hand, although structure of plasma density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF plasma.
Neutral depletion and the helicon density limit
Authors: Magee R. M. , Galante M. E. , Carr J. , Lusk G. , McCarren D. W. , Scime E. E.
Published: December 2013

It is straightforward to create fully ionized plasmas with modest rf power in a helicon. It is difficult, however, to create plasmas with density >1020 m−3, because neutral depletion leads to a lack of fuel. In order to address this density limit, we present fast (1 MHz), time-resolved measurements of the neutral density at and downstream from the rf antenna in krypton helicon plasmas. At the start of the discharge, the neutral density underneath the antenna is reduced to 1% of its initial value in 15 μs. The ionization rate inferred from these data implies that the electron temperature near the antenna is much higher than the electron temperature measured downstream. Neutral density measurements made downstream from the antenna show much slower depletion, requiring 14 ms to decrease by a factor of 1/e. Furthermore, the downstream depletion appears to be due to neutral pumping rather than ionization.
Note: Mechanical etching of atomic force microscope tip and microsphere attachment for thermal radiation scattering enhancement
Authors: Brissinger D. , Parent G. , Lacroix D.
Published: December 2013

This Note describes a mechanical etching technique which can be used to prepare silicon tips used in atomic force microscopy apparatus. For such devices, dedicated tips with specific shapes are now commonly used to probe surfaces. Yet, the control of the tip morphology where characteristic scales are lower than 1 μm remains a real challenge. Here, we detail a controlled etching process of AFM probes apex allowing micrometer-sized sphere attachment. The technique used and influent parameters are discussed and SEM images of the achieved tips are given. Deceptive problems and drawbacks that might occur during the process are also covered.
Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites
Authors: Tringe J. W. , Létant S. E. , Dugan L. C. , Levie H. W. , Kuhl A. L. , Murphy G. A. , Alves S. W. , Vandersall K. S. , Pantoya M. L.
Published: December 2013

Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300–2800 K were calculated to persist for nearly the full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%–1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.
Detailed photoluminescence studies of thin film Cu2S for determination of quasi-Fermi level splitting and defect levels
Authors: Sträter H. , Brüggemann R. , Siol S. , Klein A. , Jaegermann W. , Bauer G. H.
Published: December 2013

We have studied chalcocite (Cu2S) layers prepared by physical vapor deposition with varying deposition parameters by calibrated spectral photoluminescence (PL) and by confocal PL with lateral resolution of Δ x≈0.9 μm. Calibrated PL experiments as a function of temperature T and excitation fluxes were performed to obtain the absolute PL-yield and to calculate the splitting of the quasi-Fermi levels (QFLs) μ=Ef,n−Ef,p at an excitation flux equivalent to the AM 1.5 spectrum and the absorption coefficient α(ℏω), both in the temperature range of 20 K≤T≤400 K. The PL-spectra reveal two peaks at E#1=1.17 eV and E#2=1.3 eV. The samples show a QFL-splitting of μ>700 meV associated with a pseudo band gap of Eg=1.25 eV. The high-energy peak shows an unexpected temperature behavior, namely, an increase of PL-yield with rising temperature at variance with the behavior of QFL-splitting that decreases with rising T. Our observations indicate that, contrary to common believe, it is not the PL-yield, but rather the QFL-splitting that is the comprehensive indicator of the quality of the excited state in an illuminated semiconductor. A further examination of the lateral variation of opto-electronic properties by confocal PL and the surface contour shows no detectable correlation between Cu2S grains/grain boundaries and the PL-yield or QFL-splitting.
Ultrahigh strain-rate bending of copper nanopillars with laser-generated shock waves
Authors: Colorado H. A. , Navarro A. , Prikhodko S. V. , Yang J. M. , Ghoniem N. , Gupta V.
Published: December 2013

An experimental study to bend FIB-prepared cantilevered single crystal Cu nanopillars of several hundred nanometers in diameter and length at ultrahigh strain rate is presented. The deformation is induced by laser-generated stress waves, resulting in local strain rates exceeding 107 s−1. Loading of nano-scale Cu structures at these extremely short loading times shows unique deformation characteristics. At a nominal stress value of 297 MPa, TEM examination along with selected area electron diffraction characterization revealed that twins within the unshocked Cu pillars interacted with dislocations that nucleated from free surfaces of the pillars to form new subgrain boundaries. MD simulation results were found to be consistent with the very low values of the stress required for dislocation activation and nucleation because of the extremely high surface area to volume ratio of the nanopillars. Specifically, simulations show that the stress required to nucleate dislocations at these ultrahigh strain rates is about one order of magnitude smaller than typical values required for homogeneous nucleation of dislocation loops in bulk copper single crystals under quasi-static conditions.
Magneto-optical spectrum and the effective excitonic Zeeman splitting energies of Mn and Co-doped CdSe nanowires
Authors: Xiong Wen , Chen Wensuo
Published: December 2013

The electronic structure of Mn and Co-doped CdSe nanowires are calculated based on the six-band k·p effective-mass theory. Through the calculation, it is found that the splitting energies of the degenerate hole states in Mn-doped CdSe nanowires are larger than that in Co-doped CdSe nanowires when the concentration of these two kinds of magnetic ions is the same. In order to analysis the magneto-optical spectrum of Mn and Co-doped CdSe nanowires, the four lowest electron states and the four highest hole states are sorted when the magnetic field is applied, and the 10 lowest optical transitions between the conduction subbands and the valence subbands at the Γ point in Mn and Co-doped CdSe nanowires are shown in the paper, it is found that the order of the optical transitions at the Γ point almost do not change although two different kinds of magnetic ions are doped in CdSe nanowires. Finally, the effective excitonic Zeeman splitting energies at the Γ point are found to increase almost linearly with the increase of the concentration of the magnetic ions and the magnetic field; meanwhile, the giant positive effective excitonic g factors in Mn and Co-doped CdSe nanowires are predicted based on our theoretical calculation.
Hetero-structured lumpy nanoparticle conformal structure for high absorbance of ultrathin film amorphous silicon solar cells
Authors: Cai Boyuan , Jia Baohua , Gu Min
Published: December 2013

We present a concept for enhancing the absorbance of amorphous-silicon solar cells by using hetero-structured nanoparticles consisting of dielectric core particles combined with small metallic surface nanoparticles half embedded in the core to harness both the scattering effect and the near field light concentration. Through optimising key parameters, including the relative distance of the nanoparticles to the solar cell, the radius ratio of the core to the surface nanoparticles, and the refractive index of the core particles, the short circuit current density in a 20 nm nanoparticle-integrated active layer is equivalent to that in a 300 nm flat active layer.
Anisotropic strain relaxation and the resulting degree of polarization by one- and two-step growth in nonpolar a-plane GaN grown on r-sapphire substrate
Authors: Feng Shih-Wei , Chen Yu-Yu , Lai Chih-Ming , Tu Li-Wei , Han Jung
Published: December 2013

Anisotropic strain relaxation and the resulting degree of polarization of the electronic transition in nonpolar a-plane GaN using one- and two-step growth are studied. By using two-step growth, a slower coalescence and a longer roughening-recovery process lead to larger anisotropic strain relaxation, a less striated surface, and lower densities of basal stacking fault (BSF) and prismatic stacking fault (PSF). It is suggested that anisotropic in-plane strains, surface striation, and BSF and PSF densities in nonpolar a-GaN are consequences of the rate of coalescence, the period of roughening-recovery process, and the degree of anisotropic strain relaxation. In addition, the two-step growth mode can enhance the degree of polarization of the electronic transition. The simulation results of the k⋅p perturbation approach show that the oscillator strength and degree of polarization of the electronic transition strongly depend on the in-plane strains upon anisotropic in-plane strain relaxation. The research results provide important information for optimized growth of nonpolar III-nitrides. By using two-step growth and by fabricating the devices on the high-quality nonpolar free-standing GaN substrates, high-efficiency nonpolar a-plane InGaN LEDs can be realized. Nonpolar a-plane InGaN/GaN LEDs can exhibit a strongly polarized light to improve the contrast, glare, eye discomfort and eye strain, and efficiency in display application.
Negative magnetodielectric effect in CaCu3Ti4O12
Authors: Chen Kai , Huang Chenxi , Zhang Xirui , Yu Yuanlie , Lau Kenny , Hu Wanbiao , Li Qian , Wang Jian , Lin Weiwei , Liu Junming , Qiu Li , Zhu Jinsong , Withers Ray L.
Published: December 2013

Real part of complex relative dielectric value is relatively decreased as large as  ∼5 % from 50 K to 200 K in CaCu3Ti4O12, by applying a 6-T static magnetic field. CaCu3Ti4O12 is thus implied primarily by the negative magnetodielectric effect, as a unified dielectric system in which 1-D finite dipole chains of B-site titanium ions, coexist with a collective of polaron-like 3d-electrons of A-site copper ions: the dipole chains are thermally activated for lattice ionic polarization above 50 K, and suppressed by the short-range hop of these quasi-particles, while their long-range movement are for bulk electronic polarization above 151 K.