bluuebunny/crossref_metadata_2025 huggingface dataset:
Static analysis and simulation of piston coupled diaphragm for microelectromechanical systems based high sensitive sensors
Authors: Mahlooji Mohamad Reza , Koohsorkhi Javad
Published: March 2018

In this work, a new type of diaphragms called ‘piston coupled diaphragm’ is introduced to use as mechanical structure of sensors and micro‐electrostatic actuators. Using the static theory based on Kirchhoff–Love theory of plates, expression of deflection is derived. It is assumed that the connection bar area is rigid and simulation results show accuracy of deflection expression. In order to use piston coupled diaphragm as mechanical structure of sensors, electrical and mechanical sensitivity, dynamic range and linear behaviour of the diaphragm are studied. The results show that by choosing a proper dimension of piston coupled diaphragm, because of increased centre rigidity the mechanical sensitivity will decrease but because of realisation of piston‐like movement in mechanical structure electrical sensitivity improved by factor of about three in compression to conventional simple diaphragm with the same dimensions and also minimum detectable pressure is improved and linear behaviour of diaphragm degrades. An expression to describe linear behaviour of diaphragm up to 0.54% error from linear response is derived.
Dependence of Type Ia supernova luminosities on their local environment
Authors: Roman M. , Hardin D. , Betoule M. , Astier P. , Balland C. , Ellis R. S. , Fabbro S. , Guy J. , Hook I. , Howell D. A. , Lidman C. , Mitra A. , Möller A. , Mourão A. M. , Neveu J. , Palanque-Delabrouille N. , Pritchet C. J. , Regnault N. , Ruhlmann-Kleider V. , Saunders C. , Sullivan M.
Published: March 2018

We present a fully consistent catalog of local and global properties of host galaxies of 882 Type Ia supernovæ (SNIa) that were selected based on their light-curve properties, spanning the redshift range 0.01 < z < 1. This catalog corresponds to a preliminary version of the compilation sample and includes Supernova Legacy Survey (SNLS) 5-year data, Sloan Digital Sky Survey (SDSS), and low-redshift surveys. We measured low- and moderate-redshift host galaxy photometry in SDSS stacked and single-epoch images and used spectral energy distribution fitting techniques to derive host properties such as stellar mass and U − V rest-frame colors; the latter are an indicator of the luminosity-weighted age of the stellar population in a galaxy. We combined these results with high-redshift host photometry from the SNLS survey and thus obtained a consistent catalog of host stellar masses and colors across a wide redshift range. We also estimated the local observed fluxes at the supernova location within a proper distance radius of 3 kpc, corresponding to the SNLS imaging resolution, and transposed them into local U − V rest-frame colors. This is the first time that local environments surrounding SNIa have been measured at redshifts spanning the entire Hubble diagram. Selecting SNIa based on host photometry quality, we then performed cosmological fits using local color as a third standardization variable, for which we split the sample at the median value. We find a local color step significance of − 0.091 ± 0.013 mag (7σ), which effect is as significant as the maximum mass step effect. This indicates that the remaining luminosity variations in SNIa samples can be reduced with a third standardization variable that takes the environment into account. Correcting for the maximum mass step correction of − 0.094 ± 0.013 mag, we find a local color effect of − 0.057 ± 0.012 mag (5σ), which shows that additional information is provided by the close environment of SNIa. Departures from the initial choices were investigated and showed that the local color effect is still present, although less pronounced. We discuss the possible implications for cosmology and find that using the local color in place of the stellar mass results in a change in the measured value of the dark energy equation-of-state parameter of 0.6%. Standardization using local U − V color in addition to stretch and color reduces the total dispersion in the Hubble diagram from 0.15 to 0.14 mag. This will be of tremendous importance for the forthcoming SNIa surveys, and in particular for the Large Synoptic Survey Telescope (LSST), for which uncertainties on the dark energy equation of state will be comparable to the effects reported here.
Wavelet theory applied to the study of spectra of trans-Neptunian objects
Authors: Souza-Feliciano A. C. , Alvarez-Candal A. , Jiménez-Teja Y.
Published: March 2018

Context. Reflection spectroscopy in the near-infrared (NIR) is used to investigate the surface composition of trans-Neptunian objects (TNOs). In general, these spectra are difficult to interpret due to the low apparent brightness of the TNOs, causing low signal-to-noise ratio even in spectra obtained with the largest telescopes available on Earth, making it necessary to use filtering techniques to analyze and interpret them.

Aims. The purpose of this paper is to present a methodology to analyze the spectra of TNOs. Specifically, our aim was to filter these spectra in the best possible way: maximizing noise removal, while minimizing the loss of signal.

Methods. We used wavelets to filter the spectra. Wavelets are a mathematical tool that decompose the signal into its constituent parts, allowing us to analyze the data in different areas of frequencies with the resolution of each component tied to its scale. To check the reliability of our method, we compared the filtered spectra with the spectra of water and methanol ices to identify some common structures between them.

Results. Of the 50 TNOs in our sample, we identify traces of water ices and methanol in the spectra of several of them, some with previous reports, while for other objects there were no previous reports.

Conclusions. We conclude that the wavelet technique is successful in filtering spectra of TNOs.
Timescales of starspot variability in slow rotators
Authors: Arkhypov O. V. , Khodachenko M. L. , Güdel M. , Johnstone C. , Lüftinger T. , Lammer H.
Published: March 2018

There is an intriguing proximity between the turnover time τMLT of the standard mixing length theory of the Sun and the timescale τlam of solar activity patterns at the space scale of giant laminar convection assumed in deep layers of the Sun. To verify the reliability of this correspondence, we analyzed the light curves of 637 slowly rotating stars, observed by the Kepler mission, with periods from 16 to 30 days. The proximity τMLT ≈ τlam is confirmed. The performed study also confirms the manifestation of large scale turbulence in the dynamics of surface activity such as that in the Sun. These results open a new way to measure the key astrophysical parameter τMLT and to study deep convection that has been undetected with asteroseismology.
Goal-oriented error estimation for parameter-dependent nonlinear problems
Authors: Janon Alexandre , Nodet Maëlle , Prieur Christophe , Prieur Clémentine
Published: March 2018

The main result of this paper gives a numerically efficient method to bound the error that is made when approximating the output of a nonlinear problem depending on an unknown parameter (described by a probability distribution). The class of nonlinear problems under consideration includes high-dimensional nonlinear problems with a nonlinear output function. A goal-oriented probabilistic bound is computed by considering two phases. An offline phase dedicated to the computation of a reduced model during which the full nonlinear problem needs to be solved only a small number of times. The second phase is an online phase which approximates the output. This approach is applied to a toy model and to a nonlinear partial differential equation, more precisely the Burgers equation with unknown initial condition given by two probabilistic parameters. The savings in computational cost are evaluated and presented.
Influence of roasting olive fruit on the chemical composition and polycyclic aromatic hydrocarbon content of olive oil
Authors: Gharby Said , Harhar Hicham , Farssi Mustapha , Ait Taleb Abdelaziz , Guillaume Dominique , Laknifli Abdellatif
Published: March 2018

Alwana olive oil is a special product of the people from the mountains of Morocco. To produce this oil, prior to the pressing procedure, olives are roasted at up to 130 °C, which leads to the formation of a typical roasty and nutty aroma. It can be expected that this process, which strongly differs from the usual production technic of virgin olive oil, impact the oil chemical composition. We observed that the roasting process has no influence on the fatty acid and sterol composition of Alwana olive. Concentration in α-tocopherol underwent a slight decrease (from 93 to 91%) whereas γ-tocopherol, polyphenol, and chlorophyll content were increased by the roasting process. Polycyclic aromatic hydrocarbon content was found to be 50 µg kg−1.
Deutschlandweite Umfrage zur Wertigkeit der Ultraschalldiagnostik im
Kopf-Hals-Bereich
Authors: Heyduck Adrienne , Jecker Peter , Bozzato Alessandro
Published: March 2018

2013–2014 wurde eine deutschlandweite Umfrage zur aktuellen Anwendung und Wertigkeit der Ultraschalldiagnostik
im Kopf-Hals-Bereich durchgeführt. Hier war das Augenmerk insbesondere auf die Integration der
Ultraschalldiagnostik im praktischen Alltag des HNO-Arztes im klinischen und im niedergelassenen Bereich
gerichtet. Analysiert wurden ferner die aktuell geltenden Standardisierungsprozesse und
Ausbildungsrichtlinien.
Mundgesundheitsbezogene Lebensqualität bei Krebspatienten
Authors: Gorges Johanna , Wehler Beatrice , Krüger Maximilian , Singer Susanne
Published: March 2018

Hintergrund Bis dato existieren wenige Studien über die mundgesundheitsbezogene Lebensqualität (MLQ) bei
Patienten mit Krebserkrankungen. Die European Organisation for Research and Treatment of Cancer (EORTC) hat
kürzlich einen Fragebogen zur Erfassung der MLQ erstellt, den Quality of Life Questionnaire – Oral Health
Module 15 (EORTC QLQ-OH15). Ziel dieser Arbeit war die Identifizierung möglicher Einschränkungen von MLQ bei
Krebspatienten im klinischen Alltag.

Patienten und Methoden Die MLQ wurde zu einem nicht näher definierten Zeitpunkt während der
Akutbehandlung (t1), 2 Wochen (t2) und 3 Monate (t3) nach dem ersten
Befragungszeitpunkt mit dem EORTC QLQ-OH15 gemessen. Als mögliche Prädiktoren der MLQ wurden zu t2
Alter, Geschlecht, Bildung, Krebsentität und Therapie explorativ untersucht.

Ergebnisse 40 Patienten nahmen initial an der Studie teil. Im Vergleich zu t1 litten die
Patienten zu t2 mehr an klebrigem Speichel und Empfindlichkeit bei Essen und Trinken. Außerdem
trugen weniger Patienten eine Zahnprothese. Zu t3 zeigte sich eine Verschlechterung hinsichtlich
der Zufriedenheit über die Aufklärung von Problemen im Mundbereich. Über 50-Jährige, Frauen, Patienten mit
geringer Bildung, Tumor im Kopf- und Halsbereich, palliativer Therapie, Operation oder zielgerichteter
Krebstherapie gaben eine schlechtere MLQ zu t2 an als andere Patienten.

Die MLQ ist bei Krebspatienten von klinischer Relevanz. Sie scheint vor allem nach Ende der Therapie
eingeschränkt zu sein, und dies nicht nur bei Patienten mit Kopf-Hals-Tumoren. Der EORTC QLQ-OH15 ist trotz
seiner Kürze in der Lage, diese Unterschiede abzubilden und wird von den Patienten gut akzeptiert, sodass er
für zukünftige Studien in dem Bereich empfohlen werden kann.
Mikrobielle Keratitis, Teil 1: allgemeine Aspekte und bakterielle Keratitiden
Authors: Schmack Ingo , Müller Michael , Kohnen Thomas
Published: March 2018

Infektiöse Entzündungen der Hornhaut (mikrobielle Keratitiden) stellen potenziell visusbedrohende Erkrankungen dar. Je nach Schweregrad und Verlauf können sie bis zum Verlust des Auges führen. Entscheidend für das Sehvermögen ist, dass die Erreger schnell erkannt und zielgerichtet therapiert werden. Dieser Beitrag behandelt zunächst generelle klinische, diagnostische und therapeutische Aspekte mikrobieller Keratitiden und geht anschließend auf die Besonderheiten bakterieller Keratitiden ein. In einem zweiten Teil werden klinische, methodische und therapeutische Besonderheiten von Keratomykosen und Akanthamöbenkeratitiden besprochen [1].
Schlafstörungen und Beeinträchtigungen des Schlafs als Nebenwirkungen von Psychopharmaka: eine Bewertung der Daten aus Fachinformationen
Authors: Gahr Maximilian , Connemann Bernhard J. , Zeiss René , Fröhlich Albrecht
Published: March 2018

Gegenstand und Ziel Psychopharmakotherapie hat bei der Behandlung zahlreicher psychischer Störungen einen großen Stellenwert. Unerwünschte Arzneimittelwirkungen (UAW) beeinflussen dabei die Compliance und Verträglichkeit. Auch Beeinträchtigungen des Schlafs können als UAW einer Psychopharmakotherapie auftreten. Schlafstörungen sind mit einem erhöhten Risiko für körperliche und psychische Erkrankungen assoziiert und beeinträchtigen Kognition, Impulskontrolle, Emotionsregulation und Stimmung. Ziel der vorliegenden Arbeit ist die systematische Darstellung der Art und des Risikos für Schlafstörungen/Beeinträchtigungen des Schlafs durch häufig verordnete Psychopharmaka.

Methodik Auf der Basis des Arzneiverordnungs-Reports 2016 wurden die in Deutschland verordnungsstärksten Psychopharmaka identifiziert. Die Fachinformationen (FI) der zugehörigen Originalpräparate wurden im Hinblick auf Nennung und Häufigkeitsangaben von Schlafstörungen/Beeinträchtigungen des Schlafs gemäß der International Classification of Sleep Disorders 3 (ICSD-3) untersucht.

Ergebnisse Es wurden n = 64 FI untersucht. Bei der überwiegenden Zahl wurde mindestens eine Schlafstörung aufgeführt (50/64; 78 %). In den Kategorien Insomnien (52 %), Parasomnien (33 %) und schlafbezogene Bewegungsstörungen (20 %) wurde am häufigsten mindestens eine FI mit entsprechender UAW gefunden; schlafbezogene Atmungsstörungen (6 %) und Hypersomnien zentralnervösen Ursprungs (5 %) waren selten aufgeführt; zirkadiane Schlaf-Wach-Rhythmusstörungen wurden nicht gefunden. In den FI der vier verordnungsstärksten Wirkstoffe (Citalopram > Venlafaxin > Mirtazapin > Sertralin) war Insomnie aufgeführt. Nahezu alle untersuchten Hypnotika (Ausnahme: Chlorahlydrat) waren mit Albträumen assoziiert.

Schlussfolgerung(en) Die meisten der in Deutschland häufig verordneten Psychopharmaka können Schlafstörungen/Beeinträchtigungen des Schlafs induzieren. Bei den vier verordnungsstärksten Wirkstoffen handelte es sich um Antidepressiva und in den zugehörigen FI war jeweils Insomnie aufgeführt. Bei der Behandlung mit Psychopharmaka sollte auf das Auftreten von Schlafstörungen als eine mögliche Nebenwirkung geachtet werden.
Nicht organische Sehstörungen
Authors: Steffen Heimo
Published: March 2018

Nicht organische Sehstörungen sind in der augenärztlichen Praxis eine häufige Herausforderung. Im Kindesalter ist die häufigste Störung eine beidseits unklare Visusreduktion, im Erwachsenenalter eher eine einseitige Sehstörung. Dieser Beitrag soll den Augenarzt für Patienten mit nicht organischer Sehstörung sensibilisieren und einen Überblick über diagnostische Strategien bei Patienten mit dieser vermuteten Diagnose geben.
Mikrobielle Keratitis – Teil 2: mykotische und Akanthamöbenkeratitiden
Authors: Schmack Ingo , Müller Michael , Kohnen Thomas
Published: March 2018

Pilze und Akanthamöben stellen neben Bakterien wesentliche Ursachen für die Entstehung infektiöser Hornhauterkrankungen (mikrobielle Keratitis) und möglicher nachfolgender Erblindung des betroffenen Auges dar. Aufgrund weitgehend unspezifischer Gewebereaktionen, vor allem in den Frühstadien der Entzündung, wird die Diagnose infektiöser Hornhauterkrankungen oftmals erst verspätet gestellt. Insbesondere bei Akanthamöben sind Verwechslungen mit viralen (herpetischen) Keratitiden leicht möglich. Der behandelnde Augenarzt ist daher vor hohe diagnostische Herausforderungen gestellt.
Alternsforschung – Die Biologie des Alterns
Authors: Bidder Julia
Published: March 2018

Die Alternsforschung steckt noch in den Kinderschuhen, hat aber nach gerade einmal zwei Jahrzehnten schon bahnbrechende Erfolge zu verzeichnen. So stie-ßen Forscher vor einiger Zeit auf das erste Altersgen, das manche Fadenwürmer, Fruchtfliegen und Mäuse doppelt so lange leben lässt wie andere. Auch wir Menschen besitzen das Gen, das sich Foxo3a nennt.
Präoperative Strahlentherapie bei therapeutischer Neck Dissection
vielversprechend
Authors: Issing Peter R.
Published: March 2018

Lippert D et al. Lymph Node Yield in Therapeutic Neck Dissection: Impact of Dissection Levels and Prior
Radiotherapy. Ann Otol Rhinol Laryngol 2017; 126: 762–767
Gesetzliche Krankenversicherung – Welche Faktoren beeinflussen die
Krankenkassenwahl?
Authors: Thiem Helena
Published: March 2018

Pendzialek J et al. Measuring customer preferences in the German statutory health insurance. Eur J Health Econ
2017; 18: 831–845

Mit dem Gesundheitsstrukturgesetz von 1992 wurde u. a. die freie Krankenkassenwahl eingeführt. Diesem
Gesetzesentwurf folgten in den letzten Jahren verschiedene weitere, die den Wettbewerb innerhalb der
gesetzlichen Krankenversicherung (GKV) in Deutschland stärken und so langfristig deren Effizienz und
Qualität steigern sollten. Pendzialek et al. untersuchten aus Perspektive der Versicherten, welche
Attribute die freie Krankenkassenwahl beeinflussen.
Potenziale und Limitationen der Detektion von zirkulierenden Melanomzellen
Authors: Lüke Julia , Grisanti S. , Tura A.
Published: March 2018

Die Bestimmung und Charakterisierung zirkulierender Melanomzellen ist ein nicht invasives und komplikationsarmes Verfahren mit dem Potenzial, einen choroidalen Nävus von einem choroidalen Melanom abzugrenzen und frühzeitig einer Therapie zuführen zu können. Zukünftig bietet es die Chance, das therapeutische Ansprechen zu überwachen und bei der Therapieauswahl zu helfen. Es besteht die Hoffnung, weitere Erkenntnisse hinsichtlich des Metastasierungsprozesses zu gewinnen und damit Ansatzpunkte für die Entwicklung zielgerichteter Therapien. In diesem Artikel werden die verschiedenen Techniken der Bestimmung zirkulierender Tumorzellen vorgestellt und ihr Potenzial bzw. Limitationen diskutiert.
Präzisionsonkologie und molekulare Tumorboards – Konzepte, Chancen und Herausforderungen
Authors: Holch Julian , Westphalen Christoph , Hiddemann Wolfgang , Heinemann Volker , Jung Andreas , Metzeler Klaus
Published: March 2018

Die immer umfassendere molekulare Charakterisierung von Tumoren ermöglicht eine „Präzisionsonkologie“ mit besonders effektiven und nebenwirkungsarmen Therapien. „Targeted Therapies“ erzielen bei bestimmten Tumorentitäten große Erfolge. Jedoch bestehen Schwierigkeiten in der praktischen Umsetzung und Nutzenbewertung zunehmend individualisierter Behandlungsansätze.
Versorgungsforschung – Leitliniengerechte Spastiktherapie als versorgungspolitische
Herausforderung
Authors: Katzenmeyer Martin , Ebke Markus
Published: March 2018

Patienten mit spastischem Syndrom sind – verglichen mit den therapeutischen Best-practice-Standards –
definitiv unterversorgt. Gründe dafür liegen u. a. in strukturellen Defiziten wie Sektorengrenzen, einer
fehlenden adäquaten Patientenunterstützung und Erstattungsproblemen. Hier müssen Verbesserungsvorschläge
ansetzen, um die Versorgungssituation zu verbessern.
Bildkarten und Buch im Test – Kinderängste bewältigen
Authors: Thiede Berenike
Published: March 2018

In der Pädiatrie begegnen wir häufig Kindern, die unsicher und ängstlich sind. Für die Arbeit mit ihnen testete Berenike Thiede das Bildkartenset „Kinderängste bewältigen“ in Kombination mit dem Buch „Training mit sozial unsicheren Kindern“ aus dem Beltz Verlag. Beides hält sie für geeignet, um Kinder dabei zu unterstützen, selbstbewusster zu werden.
Infotag für Patienten und Angehörige – Angehörige brauchen Unterstützung
Authors: Barucchieri Lisa , Nicola Stelz
Published: March 2018

Zu einer teilhabeorientierten Therapie gehört die regelmäßige Einbindung des persönlichen Umfelds. Aus diesem Grund hat sich im Neuro Reha Team Pasing der Infotag etabliert. Er bietet Angehörigen wertvolle Informationen sowie Austauschmöglichkeiten mit Therapeuten und anderen Mitbetroffenen.
Detecting topology change via correlations and entanglement from gauge/gravity correspondence
Authors: Lin Hai , Zeng Keyou
Published: March 2018

We compute a momentum space version of the entanglement spectrum and entanglement entropy of general Young tableau states and one-point functions on Young tableau states. These physical quantities are used to measure the topology of the dual spacetime geometries in the context of gauge/gravity correspondence. The idea that Young tableau states can be obtained by superposing coherent states is explicitly verified. In this quantum superposition, a topologically distinct geometry is produced by superposing states dual to geometries with a trivial topology. Furthermore, we have a refined bound for the overlap between coherent states and the rectangular Young tableau state, by using the techniques of symmetric groups and representations. This bound is exponentially suppressed by the total edge length of the Young tableau. It is also found that the norm squared of the overlaps is bounded above by inverse powers of the exponential of the entanglement entropies. We also compute the overlaps between Young tableau states and other states including squeezed states and multi-mode entangled states which have similarities with those appeared in quantum information theory.
Complex contagions with timers
Authors: Oh Se-Wook , Porter Mason A.
Published: March 2018

There has been a great deal of effort to try to model social influence—including the spread of behavior, norms, and ideas—on networks. Most models of social influence tend to assume that individuals react to changes in the states of their neighbors without any time delay, but this is often not true in social contexts, where (for various reasons) different agents can have different response times. To examine such situations, we introduce the idea of a timer into threshold models of social influence. The presence of timers on nodes delays adoptions—i.e., changes of state—by the agents, which in turn delays the adoptions of their neighbors. With a homogeneously-distributed timer, in which all nodes have the same amount of delay, the adoption order of nodes remains the same. However, heterogeneously-distributed timers can change the adoption order of nodes and hence the “adoption paths” through which state changes spread in a network. Using a threshold model of social contagions, we illustrate that heterogeneous timers can either accelerate or decelerate the spread of adoptions compared to an analogous situation with homogeneous timers, and we investigate the relationship of such acceleration or deceleration with respect to the timer distribution and network structure. We derive an analytical approximation for the temporal evolution of the fraction of adopters by modifying a pair approximation for the Watts threshold model, and we find good agreement with numerical simulations. We also examine our new timer model on networks constructed from empirical data.
Theory of torsional control for G16-type molecules
Authors: Grohmann Thomas , Seideman Tamar , Leibscher Monika
Published: March 2018

We introduce a four-dimensional quantum model for describing the torsional control with moderately strong, non-resonant laser pulses of G16-type molecules in the electronic ground state, based on the symmetry-adapted variational method. We define conditions for which lower-dimensional models, commonly used to simulate the strong-field control of molecular torsions, are reliable approximations to a four-dimensional treatment. In particular, we study the role of different types of rotational-torsional couplings—the field-free coupling and the field-induced coupling—and show that the conclusions recently drawn on the role of rotational-torsional couplings in the process of torsional alignment are not correct in general. Furthermore, we demonstrate how important an adequate description of the molecular polarizability is for reliably predicting the torsional alignment.
A new perspective for analyzing complex band structures of phononic crystals
Authors: Meng Lingkai , Shi Zhifei , Cheng Zhibao
Published: March 2018

Rewriting the formulation of the Bloch waves, this paper presents a new perspective for analyzing the complex band structures of the in-plane waves in 2D phononic crystals. Using the proposed formulation, a new finite element based method is developed for analyzing 2D periodic systems. The results of the validation example prove that the proposed method can provide exact solutions for both the real and complex band structures of 2D periodic systems. Furthermore, using the proposed method, the complex band structures of a 2D periodic structure are calculated. The physical meanings of the obtained complex band structures are discussed by performing the wave mode analysis.
Effect of temperature on magnetic and impedance properties of Fe3BO6 of nanotubular structure with a bonded B2O3 surface layer
Authors: Kumari Kalpana , Ram S. , Kotnala R. K.
Published: March 2018

In this investigation, we explore a facile synthesis of Fe3BO6 in the form of small crystallites in the specific shape of nanotubes crystallized from a supercooled liquid Fe2O3-B2O3 precursor. This study includes high resolution transmission electron microscopy (HRTEM) images, magnetic, optical, and impedance properties of the sample. HRTEM images reveal small tubes of Fe3BO6 of 20 nm diameter. A well resolved hysteresis loop appears at 5 K in which the magnetization does not saturate even up to as high field as 50 kOe. It means that the Fe3BO6 nanotubes behave as highly antiferromagnetic in nature in which the surface spins do not align along the field so easily. The temperature dependent impedance describes an ionic Fe3BO6 conductor with a reasonably small activation energy Ea ∼ 0.33 eV. Impedance formalism in terms of a Cole-Cole plot shows a deviation from an ideal Debye-like behavior. We have also reported that electronic absorption spectra are over a spectral range 200–800 nm of wavelengths in order to find out how a bonded surface layer present on the Fe3BO6 crystallites tunes the 3d → 3d electronic transitions in Fe3+ ions.
Leaky-mode expansion of the electromagnetic field inside dispersive spherical cavity
Authors: Jakobsen P. , Mansuripur M. , Kolesik M.
Published: March 2018

Rigorous justification is presented for a recently introduced method to construct leaky-mode expansions of electromagnetic fields excited inside a spherical cavity filled with a dispersive, lossy medium. In a departure from the traditional approaches, our construction does not rely on Green’s functions, rather it starts from a judiciously chosen auxiliary meromorphic function. Convergence of both the series expansions and of the over-completeness relations for the leaky modes is proven for a realistic model of chromatic dispersion.
Development of a helicon ion source: Simulations and preliminary experiments
Authors: Afsharmanesh M. , Habibi M.
Published: March 2018

In the present context, the extraction system of a helicon ion source has been simulated and constructed. Results of the ion source commissioning at up to 20 kV are presented as well as simulations of an ion beam extraction system. Argon current of more than 200 μA at up to 20 kV is extracted and is characterized with a Faraday cup and beam profile monitoring grid. By changing different ion source parameters such as RF power, extraction voltage, and working pressure, an ion beam with current distribution exhibiting a central core has been detected. Jump transition of ion beam current emerges at the RF power near to 700 W, which reveals that the helicon mode excitation has reached this power. Furthermore, measuring the emission line intensity of Ar ii at 434.8 nm is the other way we have used for demonstrating the mode transition from inductively coupled plasma to helicon. Due to asymmetrical longitudinal power absorption of a half-helix helicon antenna, it is used for the ion source development. The modeling of the plasma part of the ion source has been carried out using a code, HELIC. Simulations are carried out by taking into account a Gaussian radial plasma density profile and for plasma densities in range of 1018–1019 m−3. Power absorption spectrum and the excited helicon mode number are obtained. Longitudinal RF power absorption for two different antenna positions is compared. Our results indicate that positioning the antenna near to the plasma electrode is desirable for the ion beam extraction. The simulation of the extraction system was performed with the ion optical code IBSimu, making it the first helicon ion source extraction designed with the code. Ion beam emittance and Twiss parameters of the ellipse emittance are calculated at different iterations and mesh sizes, and the best values of the mesh size and iteration number have been obtained for the calculations. The simulated ion beam extraction system has been evaluated using optimized parameters such as the gap distance between electrodes, electrodes aperture, and extraction voltage. The gap distance, ground electrode aperture, and extraction voltage have been changed between 3 and 9 mm, 2–6.5 mm, and 10–35 kV in the simulations, respectively.
Properties of coupled-cluster equations originating in excitation sub-algebras
Authors: Kowalski Karol
Published: March 2018

In this paper, we discuss properties of single-reference coupled cluster (CC) equations associated with the existence of sub-algebras of excitations that allow one to represent CC equations in a hybrid fashion where the cluster amplitudes associated with these sub-algebras can be obtained by solving the corresponding eigenvalue problem. For closed-shell formulations analyzed in this paper, the hybrid representation of CC equations provides a natural way for extending active-space and seniority number concepts to provide an accurate description of electron correlation effects. Moreover, a new representation can be utilized to re-define iterative algorithms used to solve CC equations, especially for tough cases defined by the presence of strong static and dynamical correlation effects. We will also explore invariance properties associated with excitation sub-algebras to define a new class of CC approximations referred to in this paper as the sub-algebra-flow-based CC methods. We illustrate the performance of these methods on the example of ground- and excited-state calculations for commonly used small benchmark systems.
Free energy landscape of dissociative adsorption of methane on ideal and defected graphene from ab initio simulations
Authors: Wlazło M. , Majewski J. A.
Published: March 2018

We study the dissociative adsorption of methane at the surface of graphene. Free energy profiles, which include activation energies for different steps of the reaction, are computed from constrained ab initio molecular dynamics. At 300 K, the reaction barriers are much lower than experimental bond dissociation energies of gaseous methane, strongly indicating that the graphene surface acts as a catalyst of methane decomposition. On the other hand, the barriers are still much higher than on the nickel surface. Methane dissociation therefore occurs at a higher rate on nickel than on graphene. This reaction is a prerequisite for graphene growth from a precursor gas. Thus, the growth of the first monolayer should be a fast and efficient process while subsequent layers grow at a diminished rate and in a more controllable manner. Defects may also influence reaction energetics. This is evident from our results, in which simple defects (Stone-Wales defect and nitrogen substitution) lead to different free energy landscapes at both dissociation and adsorption steps of the process.
Nitride surface chemistry influence on band offsets at epitaxial oxide/GaN interfaces
Authors: Paisley Elizabeth A. , Brumbach Michael T. , Shelton Christopher T. , Allerman Andrew A. , Atcitty Stanley , Rost Christina M. , Ohlhausen James A. , Doyle Barney L. , Sitar Zlatko , Maria Jon-Paul , Ihlefeld Jon F.
Published: March 2018

GaN surface and near-surface chemistry influence on band offsets of oxide overlayers is demonstrated through X-ray photoelectron spectroscopy measurements using epitaxial (111)-oriented MgO films on (0001)-oriented Ga-polar GaN as a case study. For identical cleaning and MgO growth conditions, GaN subsurface oxygen impurities influence the GaN bare surface band bending and the ultimate band offset to MgO heterolayers. As the GaN surface oxygen concentration increases from an atomic concentration of 0.9% to 3.4%, the valence band offset to MgO decreases from 1.68 eV to 1.29 eV, respectively. This study highlights the sensitivity of the oxide/nitride interface electronic structure to GaN epilayer preparation and growth conditions.
Analytical investigation on domain of decentered parameter for self-focusing of Hermite-cosh-Gaussian laser beam in collisional plasma
Authors: Valkunde Amol T. , Patil Sandip D. , Vhanmore Bandopant D. , Urunkar Trupti U. , Gavade Kusum M. , Takale Mansing V. , Fulari Vijay J.
Published: March 2018

In the present paper, an analytically investigated domain of decentered parameter and its effect on the self-focusing of Hermit-cosh-Gaussian (HChG) laser beams in a collisional plasma have been studied theoretically. The nonlinearity in the dielectric constant of plasma arising due to the nonuniform heating of carriers along the wavefront of the laser beam has been employed in the present investigation. The nonlinear differential equation of beam width parameter for various laser modes of HChG beam is obtained by following the standard Akhamanov's parabolic equation approach under Wentzel-Kramers-Brillouin and paraxial approximations. The analytical treatment has enabled us to define three distinct regions: self-focusing, self-trapping and defocusing, which are presented graphically.
Proteins at the air-water interface in a lattice model
Authors: Zhao Yani , Cieplak Marek
Published: March 2018

We construct a lattice protein version of the hydrophobic-polar model to study the effects of the air-water interface on the protein and on an interfacial layer formed through aggregation of many proteins. The basic unit of the model is a 14-mer that is known to have a unique ground state in three dimensions. The equilibrium and kinetic properties of the systems with and without the interface are studied through a Monte Carlo process. We find that the proteins at high dilution can be pinned and depinned many times from the air-water interface. When pinned, the proteins undergo deformation. The staying time depends on the strength of the coupling to the interface. For dense protein systems, we observe glassy effects. Thus, the lattice model yields results which are similar to those obtained through molecular dynamics in off-lattice models. In addition, we study dynamical effects induced by local temperature gradients in protein films.
Optical performance of W/B4C multilayer mirror in the soft x-ray region
Authors: Pradhan P. C. , Majhi A. , Nayak M.
Published: March 2018

W/B4C x-ray multilayers (MLs) with 300 layer pairs and a period in the range of d = 2–1.6 nm are fabricated and investigated for the x-ray optical element in the soft x-ray regime. The structural analyses of the MLs are carried out by using hard x-ray reflectivity (HXR) measurements at 8.047 keV. Well-defined successive higher order Bragg peaks (up to 3rd order) in HXR data collected up to glancing incidence angles of ∼9° reveal a good quality of the periodic structure. The ML mirrors have an average interface width of ∼0.35 nm and have a compressive residual stress of ∼0.183 GPa and 0. 827 GPa for d = 1.62 nm and d = 1.98 nm, respectively. MLs maintain structural stability over a long time, with a slight increase in interface widths of the W layers by 0.1 nm due to self-diffusion. Soft x-ray reflectivity (SXR) performances are evaluated in the energy range of 650 to 1500 eV. At energy ∼ 1489 eV, measured reflectivities (energy resolution, ΔE) are ∼ 10% (19 eV) and 4.5% (13 eV) at glancing incident angles of 12.07° and 15° for MLs having periods of 1.98 nm and 1.62 nm, respectively. The optical performance from 1600 eV to 4500 eV is theoretically analysed by considering the measured structural parameters. The structure-stress-optical performance is correlated on the basis of the mechanism of film growth. The implications of W/B4C MLs are discussed, particularly with respect to the development of ML optics with high spectral selectivity and reflectance for soft x-ray instruments.
Spatial-decomposition analysis of viscosity with application to Lennard-Jones fluid
Authors: Tu Kai-Min , Kim Kang , Matubayasi Nobuyuki
Published: March 2018

A spatial-decomposition formula is presented for viscosity. In this formula, a time correlation function conditioned by the distance between a pair of particles is introduced for the stresses exerted on the pair and is integrated over the whole region of the pair distance to determine the pair-correlation effect on the viscosity. The spatial-decomposition formula is then applied to the Lennard-Jones fluid at three thermodynamic states. The extent of spatial localization of the stress-stress correlation of pairs of Lennard-Jones particles is analyzed, and it is found that the contribution from neighboring pairs to the viscosity is large at high densities. The presence of long-range components is further pointed out and is shown to arise due to the periodicity of a simulated cell.
Oblique propagation of solitary waves in weakly relativistic magnetized plasma with kappa distributed electrons in the presence of negative ions
Authors: Salmanpoor H. , Sharifian M. , Gholipour S. , Borhani Zarandi M. , Shokri B.
Published: March 2018

The oblique propagation of nonlinear ion acoustic solitary waves (solitons) in magnetized collisionless and weakly relativistic plasma with positive and negative ions and super thermal electrons has been examined by using reduced perturbation method to obtain the Korteweg-de Vries equation that admits an obliquely propagating soliton solution. We have investigated the effects of plasma parameters like negative ion density, electrons temperature, angle between wave vector and magnetic field, ions velocity, and k (spectral index in kappa distribution) on the amplitude and width of solitary waves. It has been found out that four modes exist in our plasma model, but the analysis of the results showed that only two types of ion acoustic modes (fast and slow) exist in the plasma and in special cases only one mode could be propagated. The parameters of plasma for these two modes (or one mode) determine which one is rarefactive and which one is compressive. The main parameter is negative ions density (β) indicating which mode is compressive or rarefactive. The effects of the other plasma parameters on amplitude and width of the ion acoustic solitary waves have been studied. The main conclusion is that the effects of the plasma parameters on amplitude and width of the solitary wave strongly depend on the value of the negative ion density.
Exchange coupling effects in Co-Pt nanochessboards
Authors: Geng Liwei D. , Soffa William A. , Floro Jerrold A. , Jin Yongmei M.
Published: March 2018

To complement recent experimental findings [Vetter et al., APL Mater. 4, 096103 (2016)] on strong exchange coupling effects in Co-Pt nanochessboards featuring a single peak in the first-order reversal curve density plot and associated magnetic hardening as the characteristic structural dimension is reduced below the critical correlation length, the effects of the strong exchange coupling on the underlying magnetic domains and their evolutions are investigated using micromagnetic simulations. The nanochessboard consists of regularly distributed aligned nanorods of a magnetically hard tetragonal L10 phase and a magnetically soft cubic L12 phase, representing a unique type of exchange-coupled magnetic nanocomposites. The simulations reveal detailed magnetic domain processes specific to the nanochessboard structure and uncover an unusual dependence of the coercivity on the length scale, where an expected magnetic hardening is followed by an unexpected magnetic softening with decreasing characteristic dimension. The length scale-dependent exchange coupling effects, effective magnetic anisotropy, and magnetic domain structures and evolution pathways are analyzed to provide insights into the peculiar magnetic behaviors of Co-Pt nanochessboards.
Radial-based tail methods for Monte Carlo simulations of cylindrical interfaces
Authors: Goujon Florent , Bêche Bruno , Malfreyt Patrice , Ghoufi Aziz
Published: March 2018

In this work, we implement for the first time the radial-based tail methods for Monte Carlo simulations of cylindrical interfaces. The efficiency of this method is then evaluated through the calculation of surface tension and coexisting properties. We show that the inclusion of tail corrections during the course of the Monte Carlo simulation impacts the coexisting and the interfacial properties. We establish that the long range corrections to the surface tension are the same order of magnitude as those obtained from planar interface. We show that the slab-based tail method does not amend the localization of the Gibbs equimolar dividing surface. Additionally, a non-monotonic behavior of surface tension is exhibited as a function of the radius of the equimolar dividing surface.
The physical foundation of the reconnection electric field
Authors: Hesse M. , Liu Y.-H. , Chen L.-J. , Bessho N. , Wang S. , Burch J. L. , Moretto T. , Norgren C. , Genestreti K. J. , Phan T. D. , Tenfjord P.
Published: March 2018

Magnetic reconnection is a key charged particle transport and energy conversion process in environments ranging from astrophysical systems to laboratory plasmas [Yamada et al., Rev. Mod. Phys. 82, 603–664 (2010)]. Magnetic reconnection facilitates plasma transport by establishing new connections of magnetic flux tubes, and it converts, often explosively, energy stored in the magnetic field to kinetic energy of charged particles [J. L. Burch and J. F. Drake, Am. Sci. 97, 392–299 (2009)]. The intensity of the magnetic reconnection process is measured by the reconnection electric field, which regulates the rate of flux tube connectivity changes. The change of magnetic connectivity occurs in the current layer of the diffusion zone, where the plasma transport is decoupled from the transport of magnetic flux. Here we report on computer simulations and analytic theory to provide a self-consistent understanding of the role of the reconnection electric field, which extends substantially beyond the simple change of magnetic connections. Rather, we find that the reconnection electric field is essential to maintain the current density in the diffusion region, which would otherwise be dissipated by a set of processes. Natural candidates for current dissipation are the average convection of current carriers away from the reconnection region by the outflow of accelerated particles, or the average rotation of the current density by the magnetic field reversal in the vicinity. Instead, we show here that the current dissipation is the result of thermal effects, underlying the statistical interaction of current-carrying particles with the adjacent magnetic field. We find that this interaction serves to redirect the directed acceleration of the reconnection electric field to thermal motion. This thermalization manifests itself in form of quasi-viscous terms in the thermal energy balance of the current layer. This collisionless viscosity, found in the pressure evolution equation, dominates near the x-line. These quasi-viscous terms act to increase the average thermal energy. Our predictions regarding current and thermal energy balance are readily amenable to exploration in the laboratory or by satellite missions, in particular, by NASA's Magnetospheric Multiscale mission.
Simulation study of depositing the carbon film on nanoparticles in the magnetized methane plasma
Authors: Mohammadzadeh Hosein , Pourali Nima , Ebadi Zahra
Published: March 2018

Plasma coating of nanoparticles in low-temperature magnetized methane plasma is studied by a simulation approach. To this end, by using the global model, the electron temperature and concentration of different species considered in this plasma are determined in the center of a capacitively coupled discharge. Then, the plasma-wall transition region in the presence of an oblique magnetic field is simulated by the multi-component fluid description. Nanoparticles with different radii are injected into the transition region and surface deposition and heating models, as well as dynamics and charging models, are employed to examine the coating process. The results of the simulation show that the non-spherical growth of nanoparticles is affected by the presence of the magnetic field, as with passing time, an oscillating increase is seen in the thickness of the film deposited on nanoparticles. Also, it is shown that the uniformity of the deposited film is dependent on the rotation velocity of nanoparticles. Generally, the obtained results imply that the sphericity of nanoparticles and uniformity of the film coated on them are controllable by the magnitude and orientation of the magnetic field.
Synchrotron-based ambient pressure X-ray photoelectron spectroscopy of hydrogen and helium
Authors: Zhong Jian-Qiang , Wang Mengen , Hoffmann William H. , van Spronsen Matthijs A. , Lu Deyu , Boscoboinik J. Anibal
Published: March 2018

Contrary to popular belief, it is possible to obtain X-ray photoelectron spectra for elements lighter than lithium, namely hydrogen and helium. The literature is plagued with claims of this impossibility, which holds true for lab-based X-ray sources. However, this limitation is merely technical and is related mostly to the low X-ray photoionization cross-sections of the 1s orbitals of hydrogen and helium. In this letter, we show that, using ambient pressure X-ray photoelectron spectroscopy (XPS), a bright-enough X-ray source allows the study of these elusive elements. This has important implications in the understanding of the limitations of one of the most useful techniques in materials science, and moreover, it potentially opens the possibility of using XPS to directly study the most abundant element in the universe.
The power of talk and power in talk: a systematic review of Indigenous narratives of culturally safe healthcare communication
Authors: Jennings Warren , Bond Chelsea , Hill Peter S.
Published: March 2018

The study aimed to explore Indigenous narrative accounts of healthcare access within qualitative research papers, to better understand Indigenous views on culturally safe healthcare and health communication represented in that literature. A systematic literature review of peer-reviewed academic qualitative studies identified 65 papers containing Indigenous respondents’ views on accessing healthcare. Analysis included all Indigenous voice (primary quotations) and author findings describing healthcare access across these studies. Healthcare communication, or ‘talk’, emerged as a key theme. Indigenous clients valued talk within healthcare interactions; it was essential to their experience of care, having the power to foster relationships of trust, strengthen engagement and produce positive outcomes. By mediating the power differentials between health professionals and Indigenous clients, talk could either reinforce powerlessness, through judgmental down-talk, medical jargon or withholding of talk, or empower patients with good talk, delivered on the client’s level. Good talk is a critical ingredient to improving Indigenous accessibility and engagement with healthcare services, having the ability to minimise the power differentials between Indigenous clients and the healthcare system.