bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffraction response of photorefractive polymers over nine orders of magnitude of pulse duration
Authors: Blanche Pierre-Alexandre , Lynn Brittany , Churin Dmitriy , Kieu Khanh , Norwood Robert A. , Peyghambarian Nasser
Published: July 2016

The development of a single mode fiber-based pulsed laser with variable pulse duration, energy and repetition rate has enabled the characterization of photorefractive polymer (PRP) in a previously inaccessible regime located between millisecond and microsecond single pulse illumination. With the addition of CW and nanosecond pulse lasers, four wave mixing measurements covering 9 orders of magnitudes in pulse duration are reported. Reciprocity failure of the diffraction efficiency according to the pulse duration for a constant energy density is observed and attributed to multiple excitation, transport and trapping events of the charge carriers. However, for pulses shorter than 30 μs, the efficiency reaches a plateau where an increase in energy density no longer affects the efficiency. This plateau is due to the saturation of the charge generation at high peak power given the limited number of sensitizer sites. The same behavior is observed in two different types of devices composed of the same material but with or without a buffer layer covering one electrode, which confirm the origin of these mechanisms. This new type of measurement is especially important to optimize PRP for applications using short pulse duration.
Organelle acidification negatively regulates vacuole membrane fusion in vivo
Authors: Desfougères Yann , Vavassori Stefano , Rompf Maria , Gerasimaite Ruta , Mayer Andreas
Published: July 2016

The V-ATPase is a proton pump consisting of a membrane-integral V0 sector and a peripheral V1 sector, which carries the ATPase activity. In vitro studies of yeast vacuole fusion and evidence from worms, flies, zebrafish and mice suggested that V0 interacts with the SNARE machinery for membrane fusion, that it promotes the induction of hemifusion and that this activity requires physical presence of V0 rather than its proton pump activity. A recent in vivo study in yeast has challenged these interpretations, concluding that fusion required solely lumenal acidification but not the V0 sector itself. Here, we identify the reasons for this discrepancy and reconcile it. We find that acute pharmacological or physiological inhibition of V-ATPase pump activity de-acidifies the vacuole lumen in living yeast cells within minutes. Time-lapse microscopy revealed that de-acidification induces vacuole fusion rather than inhibiting it. Cells expressing mutated V0 subunits that maintain vacuolar acidity were blocked in this fusion. Thus, proton pump activity of the V-ATPase negatively regulates vacuole fusion in vivo. Vacuole fusion in vivo does, however, require physical presence of a fusion-competent V0 sector.
Beyond the brain-Peripheral kisspeptin signaling is essential for promoting endometrial gland development and function
Authors: León Silvia , Fernandois Daniela , Sull Alexandra , Sull Judith , Calder Michele , Hayashi Kanako , Bhattacharya Moshmi , Power Stephen , Vilos George A. , Vilos Angelos G. , Tena-Sempere Manuel , Babwah Andy V.
Published: July 2016

Uterine growth and endometrial gland formation (adenogenesis) and function, are essential for fertility and are controlled by estrogens and other regulators, whose nature and physiological relevance are yet to be elucidated. Kisspeptin, which signals via Kiss1r, is essential for fertility, primarily through its central control of the hypothalamic-pituitary-ovarian axis, but also likely through peripheral actions. Using genetically modified mice, we addressed the contributions of central and peripheral kisspeptin signaling in regulating uterine growth and adenogenesis. Global ablation of Kiss1 or Kiss1r dramatically suppressed uterine growth and almost fully prevented adenogenesis. However, while uterine growth was fully rescued by E2 treatment of Kiss1−/− mice and by genetic restoration of kisspeptin signaling in GnRH neurons in Kiss1r−/− mice, functional adenogenesis was only marginally restored. Thus, while uterine growth is largely dependent on ovarian E2-output via central kisspeptin signaling, peripheral kisspeptin signaling is indispensable for endometrial adenogenesis and function, essential aspects of reproductive competence.
Synthesis and fluxional behaviour of novel chloroborole dimers
Authors: Zhang Zuolun , Wang Zheng , Haehnel Martin , Eichhorn Antonius , Edkins Robert M. , Steffen Andreas , Krueger Anke , Lin Zhenyang , Marder Todd B.
Published: July 2016

Two (B-Cl)-chloroboroles form unsymmetric dimers which are highly fluxional in solutionviareversible enantiomerisation through an intermediate with mirror symmetry.
The rich phase behavior of the thermopolarization of water: from a reversal in the polarization, to enhancement near criticality conditions
Authors: Iriarte-Carretero Irene , Gonzalez Miguel A. , Armstrong Jeff , Fernandez-Alonso Felix , Bresme Fernando
Published: July 2016

Non-equilibrium molecular dynamics simulations show that the polarization of water induced by thermal gradients depends strongly on the thermodynamic conditions, with a large enhancement near the critical point.
In quest of cathode materials for Ca ion batteries: the CaMO3 perovskites (M = Mo, Cr, Mn, Fe, Co, and Ni)
Authors: Arroyo-de Dompablo M. E. , Krich C. , Nava-Avendaño J. , Palacín M. R. , Bardé F.
Published: July 2016

The basic electrochemical characteristics of various CaMO3 perovskites as cathode materials for Ca ion batteries are investigated using first principles calculations; CaMoO3 is identified as the most promising material.
Light stability tests of CH3NH3PbI3 perovskite solar cells using porous carbon counter electrodes
Authors: Ito Seigo , Mizuta Gai , Kanaya Shusaku , Kanda Hiroyuki , Nishina Tomoya , Nakashima Seiji , Fujisawa Hironori , Shimizu Masaru , Haruyama Yuichi , Nishino Hitoshi
Published: July 2016

Strong moisture-blocking effect by CH3NH3PbI3 perovskite-porous carbon layer has been found.
Steady-state reaction kinetics of CO oxidation catalyzed by uni-sized Pt30 clusters directly bound to Si surface
Authors: Yasumatsu H. , Fukui N.
Published: July 2016

Catalytic CO oxidation driven by uni-sized Pt30 bound to a Si substrate, at the interface of which electrons are accumulated. The low-temperature and anti-CO-poisoning performance has been evidenced with continuous and simultaneous supply of CO and O2.
Mapping the protein-binding sites for iridium(iii)-based CO-releasing molecules
Authors: Caterino Marco , Petruk Ariel A. , Vergara Alessandro , Ferraro Giarita , Marasco Daniela , Doctorovich Fabio , Estrin Dario A. , Merlino Antonello
Published: July 2016

Mass spectrometry, Raman microspectroscopy, circular dichroism and X-ray crystallography have been used to investigate the reaction of CO-releasing molecule Cs2IrCl5CO with the model protein RNase A.
Superstructure formation in SrBa8[BN2]6and EuBa8[BN2]6
Authors: Seidel Stefan , Dierkes Tobias , Jüstel Thomas , Benndorf Christopher , Eckert Hellmut , Pöttgen Rainer
Published: July 2016

X-ray pure samples of SrBa8[BN2]6and EuBa8[BN2]6were synthesized from appropriate amounts of binary nitrides (Sr3N2, Ba3N2and BN in sealed niobium ampoules and EuN, Ba3N2and BN in BN crucibles, respectively) at temperatures up to 1370 K.
Tris-ureas as transmembrane anion transporters
Authors: Olivari Martina , Montis Riccardo , Berry Stuart N. , Karagiannidis Louise E. , Coles Simon J. , Horton Peter N. , Mapp Lucy K. , Gale Philip A. , Caltagirone Claudia
Published: July 2016

Tris ureas can mediate the exchange of Cl−/NO3− and also Cl−/HCO3− across bilayer membranes.
Nitrogen oxides reduction by carbon monoxide over semi-coke supported catalysts in a simulated rotary reactor: reaction performance under dry conditions
Authors: Cheng Xingxing , Zhang Ming , Sun Peiliang , Wang Luyuan , Wang Zhiqiang , Ma Chunyuan
Published: July 2016

A novel rotary reactor was proposed for nitrogen oxides (NOx) reduction by carbon monoxide (CO) in order to avoid the oxygen inhibition effect.
Linearity testing and dead-time determination for MC-ICP-MS ion counters using the IRMM-072 series of uranium isotope reference materials
Authors: Richter S. , Konegger-Kappel S. , Boulyga S. F. , Stadelmann G. , Koepf A. , Siegmund H.
Published: July 2016

The IRMM-072 series of reference materials is applied to perform linearity testing and dead time determinations for the ion counters on two MC-ICP-MS mass spectrometers at the IAEA.
Combining pseudo dinucleotide composition with the Z curve method to improve the accuracy of predicting DNA elements: a case study in recombination spots
Authors: Dong Chuan , Yuan Ya-Zhou , Zhang Fa-Zhan , Hua Hong-Li , Ye Yuan-Nong , Labena Abraham Alemayehu , Lin Hao , Chen Wei , Guo Feng-Biao
Published: July 2016

Pseudo dinucleotide composition (PseDNC) and Z curve showed excellent performance in the classification issues of nucleotide sequences in bioinformatics.
Molecular dyad approaches to the detection and photosensitization of singlet oxygen for biological applications
Authors: You Youngmin
Published: July 2016

Molecular dyads enable the sensitization and visualization of singlet oxygen in biological systems.
Photocatalytic properties of Pd/TiO2 nanosheets for hydrogen evolution from water splitting
Authors: Wu Junjie , Lu Shuanglong , Ge Danhua , Zhang Longzhu , Chen Wei , Gu Hongwei
Published: July 2016

Pd/TiO2 nanosheet catalysts were successfully prepared and used in the photocatalytic water splitting reaction. The Pd/TiO2 nanosheet catalysts showed immensely improved photocatalytic activities compared to pure TiO2 nanosheets.
Non-covalent S⋯O interactions control conformation in a scaffold that disrupts islet amyloid polypeptide fibrillation
Authors: Peacock Hayden , Luo Jinghui , Yamashita Tohru , Luccarelli James , Thompson Sam , Hamilton Andrew D.
Published: July 2016

Rationally-designed peptidomimetics that selectively recognise protein surfaces have the potential to mediate protein-misfolding conditions.
Electrocatalytic amplification of DNA-modified nanoparticle collisions via enzymatic digestion
Authors: Castañeda Alma D. , Robinson Donald A. , Stevenson Keith J. , Crooks Richard M.
Published: July 2016

Np collisions electrochemically detected post-Exo I digestion.
Self-sorted photoconductive xerogels
Authors: Draper Emily R. , Lee Jonathan R. , Wallace Matthew , Jäckel Frank , Cowan Alexander J. , Adams Dave J.
Published: July 2016

Self-sorting between n-type and p-type gelators results in effective visible-active photoconductive xerogels.
Initial Stop Voicing in Bilingual Children With Cochlear Implants and Their Typically Developing Peers With Normal Hearing
Authors: Bunta Ferenc , Goodin-Mayeda C. Elizabeth , Procter Amanda , Hernandez Arturo
Published: July 2016

Purpose

This study focuses on stop voicing differentiation in bilingual children with normal hearing (NH) and their bilingual peers with hearing loss who use cochlear implants (CIs).

Method

Twenty-two bilingual children participated in our study (11 with NH,
M
age = 5;1 [years;months], and 11 with CIs,
M
hearing age = 5;1). The groups were matched on hearing age and a range of demographic variables. Single-word picture elicitation was used with word-initial singleton stop consonants. Repeated measures analyses of variance with three within-subject factors (language, stop voicing, and stop place of articulation) and one between-subjects factor (NH vs. CI user) were conducted with voice onset time and percentage of prevoiced stops as dependent variables.

Results

Main effects were statistically significant for language, stop voicing, and stop place of articulation on both voice onset time and prevoicing. There were no significant main effects for NH versus CI groups. Both children with NH and with CIs differentiated stop voicing in their languages and by stop place of articulation. Stop voicing differentiation was commensurate across the groups of children with NH versus CIs.

Conclusions

Stop voicing differentiation is accomplished in a similar fashion by bilingual children with NH and CIs, and both groups differentiate stop voicing in a language-specific fashion.
Development of an Electronic Documentation System for Voice Therapy: A New Teaching and Clinical Research Tool
Authors: Heller Murray Elizabeth S. , Girouard Katherine L. , Cler Gabriel J. , Stepp Cara E.
Published: July 2016

Although research on the outcomes of the treatment of voice disorders is widely discussed, there is a lack of information regarding the specifics of the methods and tasks undertaken during the therapy sessions. One reason may be a lack of a clear, standardized method of documentation for the voice therapy. Therefore, this article discusses the development of a new electronic documentation system for voice therapy. The goals of this documentation system are to create a user-friendly, flexible system that implements the standard terminology and structure proposed in the recent voice therapy taxonomy (Van Stan, Roy, Awan, Stemple, & Hillman, 2015). This documentation system stores all the information from the therapy session in a local database, which is accessible for analysis within or between patients. This allows large-scale datasets to be compiled for future clinical research. This documentation system includes definitions for all terminology and includes hierarchies, which are not required, but can be followed for additional structure. This documentation system can be used as a teaching tool, with the ability to accommodate the needs of both the novice and expert clinician.
Development of a MEMS‐based electrochemical aptasensor for norovirus detection
Authors: Kitajima Masaaki , Wang Nan , Tay Martin Q.X. , Miao Jianmin , Whittle Andrew J.
Published: July 2016

Noroviruses (NoVs) are a major cause of acute gastroenteritis worldwide and spread through person‐to‐person transmission and contaminated food or water. A miniaturised microelectromechanical systems (MEMS)‐based electrochemical aptasensor, a biosensor using aptamer as the recognition element for simple, sensitive and rapid detection of NoV has been developed. The novelty of this work is integration of MEMS technology with aptamer to develop a miniaturised and portable electrochemical sensor for environmental pathogen monitoring. An MEMS electrochemical aptasensor device was prepared by immobilising a thiolated DNA aptamer on an on‐chip gold (Au) working electrode through the affinity between thiol and Au, and formation of a DNA aptamer monolayer was confirmed by means of cyclic voltammetry as well as visual observation of a fluorescent‐labelled aptamer. The MEMS electrochemical aptasensor exhibited rapid and clear square wave voltammetry response against different titres of murine norovirus, an experimental model of human NoV. The possibility of developing a handheld aptasensor platform using a portable electrochemical measurement device is also demonstrated. This research forms initial basis for the development of an electrochemical MEMS‐aptasensor platform and its application for virus detection.
Correlation of Third Molar Status with Incidence of Condylar and Angle Fractures
Authors: Menon Suresh , Kumar Veerendra , Srihari V. , Priyadarshini Yogitha
Published: July 2016

The mandibular angle and condylar regions are most prone to fractures and this has been attributed to the presence/absence or the position of the third molars. This retrospective study was undertaken to analyze the correlation between the third molars and incidence of condylar and angle fractures in 104 patients treated for these fractures during the period from June 2009 to December 2013. Clinical and radiographic records of these patients were studied to look for the presence and position of third molars and their relation to incidence of condylar or angle fractures. There was a definite positive relation to impacted third molars and increased incidence of angle fractures. The condylar fractures were more commonly seen when the third molars were fully erupted or missing. Third molar impactions predispose to angle fractures and missing or fully erupted third molars predispose to condylar fractures.
Global robust dissipativity of interval recurrent neural networks with time-varying delay and discontinuous activations
Authors: Duan Lian , Huang Lihong , Guo Zhenyuan
Published: July 2016

In this paper, the problems of robust dissipativity and robust exponential dissipativity are discussed for a class of recurrent neural networks with time-varying delay and discontinuous activations. We extend an invariance principle for the study of the dissipativity problem of delay systems to the discontinuous case. Based on the developed theory, some novel criteria for checking the global robust dissipativity and global robust exponential dissipativity of the addressed neural network model are established by constructing appropriate Lyapunov functionals and employing the theory of Filippov systems and matrix inequality techniques. The effectiveness of the theoretical results is shown by two examples with numerical simulations.
Parametric experimental studies on mixing characteristics within a low area ratio rectangular supersonic gaseous ejector
Authors: Karthick S. K. , Rao Srisha M. V. , Jagadeesh G. , Reddy K. P. J.
Published: July 2016

We use the rectangular gaseous supersonic ejector as a platform to study the mixing characteristics of a confined supersonic jet. The entrainment ratio (ER) of the ejector, the non-mixed length (LNM), and potential core length (LPC) of the primary supersonic jet are measures to characterize mixing within the supersonic ejector. Experiments are carried out on a low area ratio rectangular supersonic ejector with air as the working fluid in both primary and secondary flows. The design Mach number of the nozzle (MPD = 1.5–3.0) and primary flow stagnation pressure (Pop = 4.89–9.89 bars) are the parameters that are varied during experimentation. Wall static pressure measurements are carried out to understand the performance of the ejector as well as to estimate the LNM (the spatial resolution is limited by the placement of pressure transducers). Well-resolved flow images (with a spatial resolution of 50 μm/pixel and temporal resolution of 1.25 ms) obtained through Planar Laser Mie Scattering (PLMS) show the flow dynamics within the ejector with clarity. The primary flow and secondary flow are seeded separately with acetone that makes the LNM and LPC clearly visible in the flow images. These parameters are extracted from the flow images using in-house image processing routines. A significant development in this work is the definition of new scaling parameters within the ejector. LNM, non-dimensionalized with respect to the fully expanded jet height hJ, is found to be a linear function of the Mach number ratio (Mach number ratio is defined as the ratio of design Mach number (MPD) and fully expanded Mach number (MPJ) of the primary jet). This definition also provides a clear demarcation of under-expanded and over-expanded regimes of operation according to [MPD/MPJ] > 1 and [MPD/MPJ] < 1, respectively. It is observed that the ER increased in over-expanded mode (to 120%) and decreased in under-expanded mode (to 68%). Similarly, LNM decreased (to 21.8%) in over-expanded mode and increased (to 20.4%) in under-expanded mode. Lengthening of LPC by 139% and a reduction of 50% in shock cell spacing have also been observed for specific flow conditions. The details regarding experimentation, analysis, and discussions are described in this article.
Phase reference in phase-sensitive sum-frequency vibrational spectroscopy
Authors: Sun Shumei , Liang Rongda , Xu Xiaofan , Zhu Heyuan , Shen Y. Ron , Tian Chuanshan
Published: July 2016

Phase-sensitive sum-frequency vibrational spectroscopy (PS-SFVS) has been established as a powerful technique for surface characterization, but for it to generate a reliable spectrum, accurate phase measurement with a well-defined phase reference is most important. Incorrect phase measurement can lead to significant distortion of a spectrum, as recently seen in the case for the air/water interface. In this work, we show theoretically and experimentally that a transparent, highly nonlinear crystal, such as quartz and barium borate, can be a good phase reference if the surface is clean and unstrained and the crystal is properly oriented to yield a strong SF output. In such cases, the reflected SF signal is dominated by the bulk electric dipole contribution and its phase is either +90° or −90°. On the other hand, materials with inversion symmetry, such as water, fused quartz, and CaF2 are not good phase references due to the quadrupole contribution and phase dispersion at the interface. Using a proper phase reference in PS-SFVS, we have found the most reliable OH stretching spectrum for the air/water interface. The positive band at low frequencies in the imaginary component of the spectrum, which has garnered much interest and been interpreted by many to be due to strongly hydrogen-bonded water species, is no longer present. A weak positive feature however still exists. Its magnitude approximately equals to that of air/D2O away from resonances, suggesting that this positive feature is unrelated to surface resonance of water.
Rate constants of chemical reactions from semiclassical transition state theory in full and one dimension
Authors: Greene Samuel M. , Shan Xiao , Clary David C.
Published: July 2016

Semiclassical Transition State Theory (SCTST), a method for calculating rate constants of chemical reactions, offers gains in computational efficiency relative to more accurate quantum scattering methods. In full-dimensional (FD) SCTST, reaction probabilities are calculated from third and fourth potential derivatives along all vibrational degrees of freedom. However, the computational cost of FD SCTST scales unfavorably with system size, which prohibits its application to larger systems. In this study, the accuracy and efficiency of 1-D SCTST, in which only third and fourth derivatives along the reaction mode are used, are investigated in comparison to those of FD SCTST. Potential derivatives are obtained from numerical ab initio Hessian matrix calculations at the MP2/cc-pVTZ level of theory, and Richardson extrapolation is applied to improve the accuracy of these derivatives. Reaction barriers are calculated at the CCSD(T)/cc-pVTZ level. Results from FD SCTST agree with results from previous theoretical and experimental studies when Richardson extrapolation is applied. Results from our implementation of 1-D SCTST, which uses only 4 single-point MP2/cc-pVTZ energy calculations in addition to those for conventional TST, agree with FD results to within a factor of 5 at 250 K. This degree of agreement and the efficiency of the 1-D method suggest its potential as a means of approximating rate constants for systems too large for existing quantum scattering methods.
Fifty years of dielectrophoretic cell separation technology
Authors: Hughes Michael P.
Published: July 2016

In 1966, Pohl and Hawk [Science 152, 647–649 (1966)] published the first demonstration of dielectrophoresis of living and dead yeast cells; their paper described how the different ways in which the cells responded to an applied nonuniform electric field could form the basis of a cell separation method. Fifty years later, the field of dielectrophoretic (DEP) cell separation has expanded, with myriad demonstrations of its ability to sort cells on the basis of differences in electrical properties without the need for chemical labelling. As DEP separation enters its second half-century, new approaches are being found to move the technique from laboratory prototypes to functional commercial devices; to gain widespread acceptance beyond the DEP community, it will be necessary to develop ways of separating cells with throughputs, purities, and cell recovery comparable to gold-standard techniques in life sciences, such as fluorescence- and magnetically activated cell sorting. In this paper, the history of DEP separation is charted, from a description of the work leading up to the first paper, to the current dual approaches of electrode-based and electrodeless DEP separation, and the path to future acceptance outside the DEP mainstream is considered.
The thermal history effect on shear band initiation in metallic glass
Authors: Wang S. , Ye Y. F. , Shi S. Q. , Yang Y.
Published: July 2016

The effect of thermal history on shear band initiation in metallic glass is investigated with spherical nanoindentation. Our results clearly show that the indentation size effect on the metallic-glass hardness varies systematically with the thermal history, which is in excellent agreement with the softening-induced shear-band initiation model we recently developed. On a fundamental level, the outcome of our research establishes a correlation between the shear modulus and the critical length scale for initiating an autocatalytic shear-band growth in metallic glasses.
Coherent interface structures and intergrain Josephson coupling in dense MgO/Mg2Si/MgB2 nanocomposites
Authors: Ueno Katsuya , Nagashima Yukihito , Seto Yusuke , Matsumoto Megumi , Sakurai Takahiro , Ohta Hitoshi , Takahashi Kazuyuki , Uchino Takashi
Published: July 2016

Many efforts are under way to control the structure of heterointerfaces in nanostructured composite materials for designing functionality and engineering application. However, the fabrication of high-quality heterointerfaces is challenging because the crystal/crystal interface is usually the most defective part of the nanocomposite materials. In this work, we show that fully dense insulator (MgO)/semiconductor(Mg2Si)/superconductor(MgB2) nanocomposites with atomically smooth and continuous interfaces, including epitaxial-like MgO/Mg2Si interfaces, are obtained by solid phase reaction between metallic magnesium and a borosilicate glass. The resulting nanocomposites exhibit a semiconductor-superconducting transition at 36 K owing to the MgB2 nanograins surrounded by the MgO/Mg2Si matrix. This transition is followed by the intergrain phase-lock transition at ∼24 K due to the construction of Josephson-coupled network, eventually leading to a near-zero resistance state at 17 K. The method not only provides a simple process to fabricate dense nanocomposites with high-quality interfaces, but also enables to investigate the electric and magnetic properties of embedded superconducting nanograins with good intergrain coupling.
Consecutive transitions from localized to delocalized transport states in the anharmonic chain of three coupled oscillators
Authors: Kislovsky V. , Kovaleva M. , Jayaprakash K. R. , Starosvetsky Y.
Published: July 2016

In the present paper, we study the mechanism of formation and bifurcations of highly nonstationary regimes manifested by different energy transport intensities, emerging in an anharmonic trimer model. The basic model under investigation comprises a chain of three coupled anharmonic oscillators subject to localized excitation, where the initial energy is imparted to the first oscillator only. We report the formation of three basic nonstationary transport states traversed by locally excited regimes. These states differ by spatial energy distribution, as well as by the intensity of energy transport along the chain. In the current study, we focus on numerical and analytical investigation of the intricate resonant mechanism governing the inter-state transitions of locally excited regimes. Results of the analytical study are in good agreement with the numerical simulations of the trimer model.
Critical phenomena at a first-order phase transition in a lattice of glow lamps: Experimental findings and analogy to neural activity
Authors: Minati Ludovico , de Candia Antonio , Scarpetta Silvia
Published: July 2016

Networks of non-linear electronic oscillators have shown potential as physical models of neural dynamics. However, two properties of brain activity, namely, criticality and metastability, remain under-investigated with this approach. Here, we present a simple circuit that exhibits both phenomena. The apparatus consists of a two-dimensional square lattice of capacitively coupled glow (neon) lamps. The dynamics of lamp breakdown (flash) events are controlled by a DC voltage globally connected to all nodes via fixed resistors. Depending on this parameter, two phases having distinct event rate and degree of spatiotemporal order are observed. The transition between them is hysteretic, thus a first-order one, and it is possible to enter a metastability region, wherein, approaching a spinodal point, critical phenomena emerge. Avalanches of events occur according to power-law distributions having exponents ≈3/2 for size and ≈2 for duration, and fractal structure is evident as power-law scaling of the Fano factor. These critical exponents overlap observations in biological neural networks; hence, this circuit may have value as building block to realize corresponding physical models.
Optimization of laser energy deposition for single-shot high aspect-ratio microstructuring of thick BK7 glass
Authors: Garzillo Valerio , Jukna Vytautas , Couairon Arnaud , Grigutis Robertas , Di Trapani Paolo , Jedrkiewicz Ottavia
Published: July 2016

We investigate the generation of high aspect ratio microstructures across 0.7 mm thick glass by means of single shot Bessel beam laser direct writing. We study the effect on the photoinscription of the cone angle, as well as of the energy and duration of the ultrashort laser pulse. The aim of the study is to optimize the parameters for the writing of a regular microstructure due to index modification along the whole sample thickness. By using a spectrally resolved single pulse transmission diagnostics at the output surface of the glass, we correlate the single shot material modification with observations of the absorption in different portions of the retrieved spectra, and with the absence or presence of spectral modulation. Numerical simulations of the evolution of the Bessel pulse intensity and of the energy deposition inside the sample help us interpret the experimental results that suggest to use picosecond pulses for an efficient and more regular energy deposition. Picosecond pulses take advantage of nonlinear plasma absorption and avoid temporal dynamics effects which can compromise the stationarity of the Bessel beam propagation.
Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry
Authors: Coury M. , Guttenfelder W. , Mikkelsen D. R. , Canik J. M. , Canal G. P. , Diallo A. , Kaye S. , Kramer G. J. , Maingi R. ,   NSTX-U team
Published: July 2016

Linear (local) gyrokinetic predictions of edge microinstabilities in highly shaped, lithiated and non-lithiated NSTX discharges are reported using the gyrokinetic code GS2. Microtearing modes dominate the non-lithiated pedestal top. The stabilization of these modes at the lithiated pedestal top enables the electron temperature pedestal to extend further inwards, as observed experimentally. Kinetic ballooning modes are found to be unstable mainly at the mid-pedestal of both types of discharges, with unstable trapped electron modes nearer the separatrix region. At electron wavelengths, electron temperature gradient (ETG) modes are found to be unstable from mid-pedestal outwards for ηe, exp ∼2.2, with higher growth rates for the lithiated discharge. Near the separatrix, the critical temperature gradient for driving ETG modes is reduced in the presence of lithium, reflecting the reduction of the lithiated density gradients observed experimentally. A preliminary linear study in the edge of non-lithiated discharges shows that the equilibrium shaping alters the electrostatic modes stability, which was found more unstable at high plasma shaping.
Elastic airtight container for the compaction of air-sensitive materials
Authors: Shoulders W. Taylor , Locke Richard , Gaume Romain M.
Published: July 2016

We report on the design and fabrication of a simple and versatile elastic canister for the compaction and hot-pressing of air-sensitive materials. This device consists of a heated double-ended floating die assembly, enclosed in a compressible stainless steel bellows that allows the action of an external hydraulic press in a uniaxial motion. The enclosure is fitted with vacuum, gas, and electrical feedthroughs to allow for atmosphere control, heating, and in situ process monitoring. The overall chamber is compact enough to be portable and transferrable into and out of a standard laboratory glovebox, thus eliminating the problem of exposing samples to ambient atmosphere during loading and unloading. Our design has been tested up to 600 °C and 7500 kg-force applied load, conditions within which transparent ceramics of anhydrous halides can be produced.
Note: Application of a novel 2(3HUS+S) parallel manipulator for simulation of hip joint motion
Authors: Shan X. L. , Cheng G. , Liu X. Z.
Published: July 2016

In the paper, a novel 2(3HUS+S) parallel manipulator, which has two moving platforms, is proposed. The parallel manipulator is adopted to simulate hip joint motion and can conduct an experiment for two hip joints simultaneously. Motion experiments are conducted in the paper, and the recommended hip joint motion curves from ISO14242 and actual hip joint motions during jogging and walking are selected as the simulated motions. The experimental results indicate that the 2(3HUS+S) parallel manipulator can realize the simulation of many kinds of hip joint motions without changing the structure size.
Impact of mechanical stress on ferroelectricity in (Hf0.5Zr0.5)O2 thin films
Authors: Shiraishi Takahisa , Katayama Kiliha , Yokouchi Tatsuhiko , Shimizu Takao , Oikawa Takahiro , Sakata Osami , Uchida Hiroshi , Imai Yasuhiko , Kiguchi Takanori , Konno Toyohiko J. , Funakubo Hiroshi
Published: July 2016

To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf0.5Zr0.5)O2 thin films were deposited on (111)Pt-coated SiO2, Si, and CaF2 substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10−6/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf0.5Zr0.5)O2 thin films deposited on SiO2 and Si substrates were under in-plane tensile strain and that their volume fraction of monoclinic phase decreased as this strain increased. In contrast, films deposited on CaF2 substrates were under in-plane compressive strain, and their volume fraction of monoclinic phase was the largest among the three kinds of substrates. The maximum remanent polarization of 9.3 μC/cm2 was observed for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2, while ferroelectricity was barely observable for Pt/(Hf0.5Zr0.5)O2/Pt/TiO2/SiO2/CaF2. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf0.5Zr0.5)O2 thin films.
3D analysis of eddy current loss in the permanent magnet coupling
Authors: Zhu Zina , Meng Zhuo
Published: July 2016

This paper first presents a 3D analytical model for analyzing the radial air-gap magnetic field between the inner and outer magnetic rotors of the permanent magnet couplings by using the Amperian current model. Based on the air-gap field analysis, the eddy current loss in the isolation cover is predicted according to the Maxwell’s equations. A 3D finite element analysis model is constructed to analyze the magnetic field spatial distributions and vector eddy currents, and then the simulation results obtained are analyzed and compared with the analytical method. Finally, the current losses of two types of practical magnet couplings are measured in the experiment to compare with the theoretical results. It is concluded that the 3D analytical method of eddy current loss in the magnet coupling is viable and could be used for the eddy current loss prediction of magnet couplings.
Analog switching in the nanocolloids of ferroelectric liquid crystals
Authors: Kumar Pradeep , Kishore Avinash , Sinha Aloka
Published: July 2016

Nanoparticle (NP) dispersion in liquid crystals (LCs) results in significant changes in the physical properties of the existing LC mixtures. Two ferroelectric liquid crystals (FLCs), 5F6T and 6F6T, have been studied for analog switching. The 5F6T sample is doped with titanium dioxide (TiO2) NPs of two different concentrations of the same average particle size and another FLC 6F6T is systematically doped with barium titanate (BaTiO3) NPs of two different average particle sizes at the same concentration. The frequency and temperature dependence of the coercive voltage of FLC nanocolloids has been studied. The V-shaped switching was observed in the case of nano-doped FLCs. The value of inversion frequency for the 5F6T+1.0 wt.% TiO2 doped sample is 30 Hz while it is 24 Hz for the 6F6T+0.5 wt.% BaTiO3 (particle size 5–10 nm) doped sample. The conductivity measurements show that the conductivity of doped samples is higher than the conductivity of their parental FLCs and can be considered the main reason for the V-shaped switching in the FLC nanocolloids, which was initially absent in their parental FLCs.
Fabrication and structural properties of AlN submicron periodic lateral polar structures and waveguides for UV-C applications
Authors: Alden D. , Guo W. , Kirste R. , Kaess F. , Bryan I. , Troha T. , Bagal A. , Reddy P. , Hernandez-Balderrama Luis H. , Franke A. , Mita S. , Chang C.-H. , Hoffmann A. , Zgonik M. , Collazo R. , Sitar Z.
Published: July 2016

Periodically poled AlN thin films with submicron domain widths were fabricated for nonlinear applications in the UV-VIS region. A procedure utilizing metalorganic chemical vapor deposition growth of AlN in combination with laser interference lithography was developed for making a nanoscale lateral polarity structure (LPS) with domain size down to 600 nm. The Al-polar and N-polar domains were identified by wet etching the periodic LPS in a potassium hydroxide solution and subsequent scanning electron microscopy (SEM) characterization. Fully coalesced and well-defined vertical interfaces between the adjacent domains were established by cross-sectional SEM. AlN LPSs were mechanically polished and surface roughness with a root mean square value of ∼10 nm over a 90 μm × 90 μm area was achieved. 3.8 μm wide and 650 nm thick AlN LPS waveguides were fabricated. The achieved domain sizes, surface roughness, and waveguides are suitable for second harmonic generation in the UVC spectrum.
Elastic constants of GaN between 10 and 305 K
Authors: Adachi K. , Ogi H. , Nagakubo A. , Nakamura N. , Hirao M. , Imade M. , Yoshimura M. , Mori Y.
Published: July 2016

Using the antenna-transmission resonant ultrasound spectroscopy, we measured the elastic constants of GaN between 10 and 305 K using 72 resonance frequencies. The mode Grüneisen parameter is determined from temperature dependence of each elastic constant, which is larger along the c axis than along the a axis, showing anisotropy in lattice anharmonicity. The zero-temperature elastic constants, determined using the Einstein-oscillator model, yield the Debye characteristic temperature of 636 K. The ab-initio calculation is carried out for deducing the elastic constants, and comparison between calculations and measurements at 0 K reveals that the local-density-approximation potential is preferable for theoretically evaluating characteristics of GaN. The theoretical calculation also supports the anisotropy in lattice anharmonicity.
Magnetostructural phase transitions and magnetocaloric effect in Tb-Dy-Ho-Co-Al alloys with a Laves phase structure
Authors: Tereshina I. S. , Chzhan V. B. , Tereshina E. A. , Khmelevskyi S. , Burkhanov G. S. , Ilyushin A. S. , Paukov M. A. , Havela L. , Karpenkov A. Yu. , Cwik J. , Koshkid'ko Yu. S. , Miller M. , Nenkov K. , Schultz L.
Published: July 2016

The influence of simultaneous substitution within the rare earth (R) and Co sublattices on the structural, magnetic, and magnetocaloric properties of the Laves phase RCo2-type compounds is studied. Main attention is devoted to the studies of the magnetostructural phase transitions and the transition types with respect to the alloy composition. Multicomponent alloys Tbx(Dy0.5Ho0.5)1−xCo2 and Tbx(Dy0.5Ho0.5)1−xCo1.75Al0.25 were prepared with the use of high purity metals. Majority of the Tbx(Dy0.5Ho0.5)1−xCo2 alloys exhibit magnetic transitions of the first-order type and a large magnetocaloric effect. The substitution of Al for Co in Tbx(Dy0.5Ho0.5)1−xCo2 increases the Curie temperature (TC) but changes the transition type from first-to the second-order. The discussion of the physical mechanisms behind the observed phenomena is given on the basis of the first principles electronic-structure calculations taking into account both the atomic disorder and the magnetic disorder effects at finite temperatures. The advantage of Al-containing materials is that sufficiently high magnetocaloric effect values are preserved at T > TC.
Electronic structure and metallization of cubic GdH3 under pressure: Ab initio many-body GW calculations
Authors: Kong Bo , Zhang Yachao
Published: July 2016

The electronic structures of the cubic GdH3 are extensively investigated using the ab initio many-body GW calculations treating the Gd 4f electrons either in the core (4f-core) or in the valence states (4f-val). Different degrees of quasiparticle (QP) self-consistent calculations with the different starting points are used to correct the failures of the GGA/GGA + U/HSE03 calculations. In the 4f-core case, GGA + G0W0 calculations give a fundamental band gap of 1.72 eV, while GGA+ GW0 or GGA + GW calculations present a larger band gap. In the 4f-val case, the nonlocal exchange-correlation (xc) functional HSE03 can account much better for the strong localization of the 4f states than the semilocal or Hubbard U corrected xc functional in the Kohn–Sham equation. We show that the fundamental gap of the antiferromagnetic (AFM) or ferromagnetic (FM) GdH3 can be opened up by solving the QP equation with improved starting point of eigenvalues and wave functions given by HSE03. The HSE03 + G0W0 calculations present a fundamental band gap of 2.73 eV in the AFM configuration, and the results of the corresponding GW0 and GW calculations are 2.89 and 3.03 eV, respectively. In general, for the cubic structure, the fundamental gap from G0W0 calculations in the 4f-core case is the closest to the real result. By G0W0 calculations in the 4f-core case, we find that H or Gd defects can strongly affect the band structure, especially the H defects. We explain the mechanism in terms of the possible electron correlation on the hydrogen site. Under compression, the insulator-to-metal transition in the cubic GdH3 occurs around 40 GPa, which might be a satisfied prediction.
Detection of special nuclear material from delayed neutron emission induced by a dual-particle monoenergetic source
Authors: Mayer M. , Nattress J. , Jovanovic I.
Published: July 2016

Detection of unique signatures of special nuclear materials is critical for their interdiction in a variety of nuclear security and nonproliferation scenarios. We report on the observation of delayed neutrons from fission of uranium induced in dual-particle active interrogation based on the 11B(d,n γ)12C nuclear reaction. Majority of the fissions are attributed to fast fission induced by the incident quasi-monoenergetic neutrons. A Li-doped glass–polymer composite scintillation neutron detector, which displays excellent neutron/γ discrimination at low energies, was used in the measurements, along with a recoil-based liquid scintillation detector. Time-dependent buildup and decay of delayed neutron emission from 238U were measured between the interrogating beam pulses and after the interrogating beam was turned off, respectively. Characteristic buildup and decay time profiles were compared to the common parametrization into six delayed neutron groups, finding a good agreement between the measurement and nuclear data. This method is promising for detecting fissile and fissionable materials in cargo scanning applications and can be readily integrated with transmission radiography using low-energy nuclear reaction sources.
High thermal stability and sluggish crystallization kinetics of high-entropy bulk metallic glasses
Authors: Yang M. , Liu X. J. , Ruan H. H. , Wu Y. , Wang H. , Lu Z. P.
Published: July 2016

Metallic glasses are metastable and their thermal stability is critical for practical applications, particularly at elevated temperatures. The conventional bulk metallic glasses (BMGs), though exhibiting high glass-forming ability (GFA), crystallize quickly when being heated to a temperature higher than their glass transition temperature. This problem may potentially be alleviated due to the recent developments of high-entropy (or multi-principle-element) bulk metallic glasses (HE-BMGs). In this work, we demonstrate that typical HE-BMGs, i.e., ZrTiHfCuNiBe and ZrTiCuNiBe, have higher kinetic stability, as compared with the benchmark glass Vitreoy1 (Zr41.2Ti13.8Cu12.5Ni10Be22.5) with a similar chemical composition. The measured activation energy for glass transition and crystallization of the HE-BMGs is nearly twice that of Vitreloy 1. Moreover, the sluggish crystallization region ΔTpl-pf, defined as the temperature span between the last exothermic crystallization peak temperature Tpl and the first crystallization exothermic peak temperature Tpf, of all the HE-BMGs is much wider than that of Vitreloy 1. In addition, high-resolution transmission electron microscopy characterization of the crystallized products at different temperatures and the continuous heating transformation diagram which is proposed to estimate the lifetime at any temperature below the melting point further confirm high thermal stability of the HE-BMGs. Surprisingly, all the HE-BMGs show a small fragility value, which contradicts with their low GFA, suggesting that the underlying diffusion mechanism in the liquid and the solid of HE-BMGs is different.
Magnetic-field-free thermoelectronic power conversion based on graphene and related two-dimensional materials
Authors: Wanke R. , Hassink G. W. J. , Stephanos C. , Rastegar I. , Braun W. , Mannhart J.
Published: July 2016

Mobile energy converters require, in addition to high conversion efficiency and low cost, a low mass. We propose to utilize thermoelectronic converters that use 2D-materials such as graphene for their gate electrodes. Deriving the ultimate limit for their specific energy output, we show that the positive energy output is likely close to the fundamental limit for any conversion of heat into electric power. These converters may be valuable as electric power sources of spacecraft, and with the addition of vacuum enclosures, for power generation in electric planes and cars.
Impact of charge carrier injection on single-chain photophysics of conjugated polymers
Authors: Hofmann Felix J. , Vogelsang Jan , Lupton John M.
Published: July 2016

Charges in conjugated polymer materials have a strong impact on the photophysics and their interaction with the primary excited state species has to be taken into account in understanding device properties. Here, we employ single-molecule spectroscopy to unravel the influence of charges on several photoluminescence (PL) observables. The charges are injected either stochastically by a photochemical process or deterministically in a hole-injection sandwich device configuration. We find that upon charge injection, besides a blue-shift of the PL emission and a shortening of the PL lifetime due to quenching and blocking of the lowest-energy chromophores, the non-classical photon arrival time distribution of the multichromophoric chain is modified towards a more classical distribution. Surprisingly, the fidelity of photon antibunching deteriorates upon charging, whereas one would actually expect the opposite: the number of chromophores to be reduced. A qualitative model is presented to explain the observed PL changes. The results are of interest to developing a microscopic understanding of the intrinsic charge-exciton quenching interaction in devices.