bluuebunny/crossref_metadata_2025 huggingface dataset:
Wave farms grid code compliance in isolated small power systems
Authors: Villalba Isabel , Blanco Marcos , Pérez‐Díaz Juan I. , Fernández Daniel , Díaz Felipe , Lafoz Marcos
Published: October 2018

Wave energy is one of the electric generation options based on renewable energies, especially suitable for islands due to the energy resource availability and the higher energy cost of energy in its electric grids. The oscillating nature of the wave resource is prone to produce negative impacts in these electric grids when considering scenarios of high penetration of wave energy generation. This study analyses the impact of wave energy generation on the power system frequency for the particular case study of Tenerife Island (Spain). Then, hourly data related to sea states in Tenerife, during a whole year, will be provided to generate an electric power profile, based on a model of a wave energy farm with a specific wave converter type. A previously developed dynamic simulation model of the Tenerife transmission network will be fed with these power profiles and the hourly electric generation and consumption profiles to analyse the system frequency. A complete set of analysis during the whole year will be accomplished in order to determine the number of over‐frequency events according to the grid codes. Finally, some corrective measures will be proposed as conclusions, e.g. energy storage devices, as the most reliable solution to mitigate frequency deviations.
FEM-BEM Coupling for Electromagnetism with the Sparse Cardinal Sine Decomposition,
Authors: Alouges Francois , Aussal Matthieu , Parolin Emile
Published: October 2018

This paper presents a FEM-BEM coupling method suitable for the numerical simulation of the electromagnetic scattering of objects composed of dielectric materials and perfect electric conduc- tors. The originality of the approach lies in part in the use of the newly proposed Sparse Cardinal Sine Decomposition SCSD) method for the BEM part of the computation and the fact that the simulation software is almost entirely written in MATLAB.

The performance of the method is illustrated by the computation of the electromagnetic scattering by an UAV-like object with two RAM regions proposed in the workshop ISAE EM 2016.
Parallel Geothermal Numerical Model with Fractures and Multi-Branch Wells
Authors: Beaude Laurence , Beltzung Thibaud , Brenner Konstantin , Lopez Simon , Masson Roland , Smai Farid , Thebault Jean-frédéric , Xing Feng
Published: October 2018

To answer the need for an efficient and robust geothermal simulation tool going beyond existing code capabilities in terms of geological and physical complexity, we have started to develop a parallel geothermal simulator based on unstructured meshes. The model takes into account complex geology including fault and fracture networks acting as major heat and mass transfer corridors and complex physics coupling the mass and energy conservations to the thermodynamic equilibrium between the gas and liquid phases. The objective of this Cemracs project was to focus on well modeling which is a key missing ingredient in our current simulator in order to perform realistic geothermal studies both in terms of monitoring and in terms of history matching. The well is discretized by a set of edges of the mesh in order to represent efficiently slanted or multi-branch wells on unstructured meshes. The connection with the 3D matrix and the 2D fracture network at each node of the well is accounted for using Peaceman’s approach. The non-isothermal flow model inside the well is based on the usual single unknown approach assuming the hydrostatic and thermodynamical equilibrium inside the well. The parallelization of the well model is implemented in such a way that the assembly of the Jacobian at each Newton step and the computation of the pressure drops inside the well can be done locally on each process without MPI communications.
Fast Solution of Boundary Integral Equations for Elasticity Around a Crack Network: A Comparative Study
Authors: Ben Gharbia Ibtihel , Bonazzoli Marcella , Claeys Xavier , Marchand Pierre , Tournier Pierre-Henri
Published: October 2018

Because of the non-local nature of the integral kernels at play, the discretization of boundary integral equations leads to dense matrices, which would imply high computational complexity. Acceleration techniques, such as hierarchical matrix strategies combined with Adaptive Cross Approximation (ACA), are available in literature. Here we apply such a technique to the solution of an elastostatic problem, arising from industrial applications, posed at the surface of highly irregular cracks networks.
Targeting Realistic Geometry in Tokamak Code Gysela
Authors: Bouzat Nicolas , Bressan Camilla , Grandgirard Virginie , Latu Guillaume , Mehrenberger Michel
Published: October 2018

In magnetically confined plasmas used in Tokamak, turbulence is respon-sible for specific transport that limits the performance of this kind of reactors. Gyroki-netic simulations are able to capture ion and electron turbulence that give rise to heat losses, but require also state-of-the-art HPC techniques to handle computation costs. Such simulations are a major tool to establish good operating regime in Tokamak such as ITER, which is currently being built. Some of the key issues to address more re- alistic gyrokinetic simulations are: efficient and robust numerical schemes, accurate geometric description, good parallelization algorithms. The framework of this work is the Semi-Lagrangian setting for solving the gyrokinetic Vlasov equation and the Gy-sela code. In this paper, a new variant for the interpolation method is proposed that can handle the mesh singularity in the poloidal plane at r = 0 (polar system is used for the moment in Gysela). A non-uniform meshing of the poloidal plane is proposed instead of uniform one in order to save memory and computations. The interpolation method, the gyroaverage operator, and the Poisson solver are revised in order to cope with non-uniform meshes. A mapping that establish a bijection from polar coordinates to more realistic plasma shape is used to improve realism. Convergence studies are provided to establish the validity and robustness of our new approach.
Numerical Simulation of Wall-Bounded Flows using a Spectral Method with Volume Penalization
Authors: Sawamura Yoichi , Yoshimatsu Katsunori , Schneider Kai
Published: October 2018

The volume penalization method, which allows to impose no-slip boundary conditions, is assessed for wall-bounded flows. For the numerical solution of the penalized equations a spectral method is used. Considering a two-dimensional Poiseuille flow, the solution of the Navier-Stokes penalized equation is computed analytically and the convergence of the numerical solution is studied. To illustrate the properties of the approach we compute a three-dimensional turbulent channel flow imposing a constant flow rate. The obtained results are compared with reference data of Kim et al. [10].
Ambulante Cochlea-Implantation: was führt zur stationären Aufnahme?
Authors: Issing Peter R.
Published: October 2018

Patel TA et al. Clinical Indicators of Admission for Pediatric Cochlear Implant Procedures. Ann Otol Rhinol Laryngol 2018; 127: 470–474

Eine ambulante Cochlea-Implantation bei Kindern gilt als sicher. Allerdings wird eine Minderheit über Nacht stationär aufgenommen. In Studien wird nahezu
ausschließlich über postoperative Komplikationen und Behandlungsergebnisse und kaum über prognostische Indikatoren des Outcomes berichtet. Daher suchten
amerikanische HNO-Ärzte nach Parametern, die mit der stationären Aufnahme korrelieren und prüften die Auswirkungen auf das klinische Ergebnis.
Larynxpapillomatose
Authors: Nawka Tadeus
Published: October 2018

Humane Papillomviren verursachen den gutartigen Epitheltumor, der bei Kehlkopfbefall zu Heiserkeit und Atemnot führt. Die Larynxpapillomatose ist nicht
heilbar, gegenwärtig ist die phonochirurgische Behandlung das Mittel der Wahl.
Diagnostik und operative Therapie der Otosklerose
Authors: Plontke Stefan K. , Metasch Marie-Luise , Zirkler Jonas , Zahnert Thomas
Published: October 2018

Für die – oft in Diagnostik und Therapie anspruchsvolle – Otosklerose kann bei richtiger Diagnosestellung eine operative oder apparative Hörrehabilitation mit
sehr hohen Erfolgschancen in Aussicht gestellt werden. Der erste Teil des Fortbildungsbeitrags umfasste Grundlagen, Diagnostik und Differenzialdiagnostik, im
zweiten Teil soll auf therapeutische Aspekte und Nachsorge eingegangen werden.
Bessere Lifebalance durch Bildung
Authors: Hasebrook Joachim , Hingst Peter , Hoffmann Wolfgang , Hahnenkamp Klaus
Published: October 2018

Seit Jahren gibt es eine deutliche Tendenz im OP: mehr Fälle, mehr Arbeit, weniger Personal, schlechte Bezahlung, kaum Aufstiegschancen. Haben Sie sich deshalb
auch schon mal gefragt, warum Sie eigentlich tagtäglich am OP-Tisch stehen? Unsere Autoren zeigen auf, welche neuen Modelle in der Pflegebildung erforderlich
sind, um für zukünftige Anforderungen gerüstet zu sein, die Arbeitsbedingungen zu verbessern und so die Lifebalance zu steigern.
Anmerkungen zur Minimal-invasiven Otoplastik (MIO)
Authors: Benedict Martin
Published: October 2018

Die minimal-invasive Otoplastik (MIO) ist nach unseren inzwischen sehr umfangreichen Erfahrungen eine zuverlässige Technik zur Korrektur abstehender Ohren. Sie
bringt bei richtiger Indikation ästhetisch ansprechende natürliche und dauerhafte Ergebnisse. Die Grenzen der minimalinvasiven Technik müssen allerdings erkannt
und berücksichtigt werden. Neue Instrumente erleichtern den Eingriff und verringern Komplikationsraten. V. a. Keloide und große hypertrophe Narben infolge
ausgedehnter Hautinzisionen und -resektionen auf der Ohrmuschelrückseite sind mit der MIO fast ausgeschlossen.

Wir stellen unser über zwei Jahrzehnte gewachsenes operatives Konzept vor.
Die Sterilisierung von Medizinprodukten
Authors: Mewis Dirk
Published: October 2018

Bei Problemen in der Zentralen Sterilgutaufbereitung und im Kampf gegen Krankenhausinfektionen unterstützen externe Dienstleister die Kliniken.
Gestational Diabetes – Major New Clinically Relevant Aspects
Authors: Schäfer-Graf Ute
Published: October 2018

The implementation of screening for gestational diabetes (GDM) in the German Prenatal Care guidelines of 2012 and the publication of numerous new studies have led to clinically relevant changes in the care of pregnant women with GDM to whom consideration was given in the new S3 Guideline on the Diagnosis, Management and Follow-up of Gestational Diabetes (AWMF 057/008) published in March this year. Certain aspects are addressed and discussed on the basis of additional background information.
Phantom Nodules Detected by Ultrasound Examination of the Neck: The Possibility of Ectopic Cervical Thymic Tissue in Adults
Authors: Ota Hisashi , Hirokawa Mitsuyoshi , Suzuki Ayana , Oshita Maki , Ito Aki , Fukushima Mitsuhiro , Kobayashi Kaoru , Miyauchi Akira
Published: October 2018

The aim of this study was to investigate the ultrasound characteristics and clinical significance of slightly hyperechoic lesions, referred to as phantom nodules, in the perithyroidal area in patients.

A total of 128 patients who underwent thyroidectomy with central neck lymph node dissection at Kuma Hospital in Hyogo, Japan were included in the study. We detected 16 phantom nodules during preoperative ultrasound examinations, defined as slightly hyperechoic masses located in the perithyroidal areas, in 13 of these 128 patients (10.2%; mean age: 55.6 years, range: 36–75 years).

All phantom nodules were located in the caudal region of the thyroid gland, and the mean maximum dimension was 7.2 mm. 12 of the 16 nodules were round or oval, while the remaining 4 were fusiform and molded by the surrounding tissue. All nodules were well-defined, solid, homogeneous, hyperechoic masses. No speckled echo pattern, internal linear echo, or vascular flow signal was observed. All 4 nodules subjected to histological examination were composed of ectopic thymic tissue. In 2 of these 4, the parenchyma was severely involuted and almost entirely replaced by adipose tissue.

To the best of our knowledge, this is the first report wherein some of the detected hyperechoic perithyroidal masses were composed of ectopic thymic tissue, and some were primarily composed of adipose tissue that completely replaced involuted ectopic thymic tissue. The results of the study suggest that these so-called phantom nodules are clinically insignificant and do not require fine needle aspiration cytology or further investigation.
Performance measures for ERCP and endoscopic ultrasound: a European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative
Authors: Domagk Dirk , Oppong Kofi W. , Aabakken Lars , Czakó Laszlo , Gyökeres Tibor , Manes Gianpiero , Meier Peter , Poley Jan-Werner , Ponchon Thierry , Tringali Andrea , Bellisario Cristina , Minozzi Silvia , Senore Carlo , Bennett Cathy , Bretthauer Michael , Hassan Cesare , Kaminski Michal F. , Dinis-Ribeiro Mario , Rees Colin J. , Spada Cristiano , Valori Roland , Bisschops Raf , Rutter Matthew D.
Published: October 2018

The European Society of Gastrointestinal Endoscopy and United European Gastroenterology present a short list of key performance measures for endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP). We recommend that endoscopy services across Europe adopt the following seven key and one minor performance measures for EUS and ERCP, for measurement and evaluation in daily practice at center and endoscopist level:

1 Adequate antibiotic prophylaxis before ERCP (key performance measure, at least 90 %); 2 Antibiotic prophylaxis before EUS-guided puncture of cystic lesions (key performance measure, at least 95 %); 3 Bile duct cannulation rate (key performance measure, at least 90 %); 4 Tissue sampling during EUS (key performance measure, at least 85 %); 5 Appropriate stent placement in patients with biliary obstruction below the hilum (key performance measure, at least 95 %); 6 Bile duct stone extraction (key performance measure, at least 90 %); 7 Post-ERCP pancreatitis (key performance measure, less than 10 %). 8 Adequate documentation of EUS landmarks (minor performance measure, at least 90 %).

This present list of quality performance measures for ERCP and EUS recommended by ESGE should not be considered to be exhaustive: it might be extended in future to address further clinical and scientific issues.
Postmortem Analysis of Vitreous Humor For Detection of Antemortem Disorders in Glucose Metabolism. An Old Method Revisited
Authors: Holstein Andreas , Titze Ulf , Hess Cornelius
Published: October 2018

It has been estimated that 15% up to one third of cases of deaths due to diabetic ketoacidosis occur in individuals with so far unknown diabetes. Moreover, cardiac arrhythmias that occur during nocturnal hypoglycaemia include bradycardia and ectopics that may provoke lethal arrhythmias. As postmortem capillary glucose concentrations have no diagnostic value, the postmortem forensic proof of hyperglycaemia or hypoglycaemia remains a challenge. The established but rarely applied method of postmortem determination of glucose and lactate in vitreous humor with or without calculation of the sum formula of Traub could provide reliable exclusion or proof of severe antemortem disorders in glucose metabolism. To date, diagnostic puncture of vitreous humor is more established for the postmortem detection of diabetic ketoacidosis than for the exclusion or proof of lethal hypoglycaemia. Vitreous humor is protected from postmortem degradation and contamination due to its isolated localization. The autolytic process in vitreous humor is considerably delayed compared to blood or liquor. In vitreous humor also the triggering agent of hypoglycaemia (insulin, insulin analogues) is easier to be detected than in blood since insulins are very unstable in postmortem blood. Furthermore, parameters of long term glycaemic control such as 1,5-anhydroglucitol, HbA1c and fructosamine can be determined in vitreous humor. However, limitations and interference factors of this method should be carefully considered. So far, clinical diabetology has taken no broad notice of this useful forensic procedure.
The Relationship Between Bone Mineral Density and Type 2 Diabetes in Obese Children and Adolescents at the Time of Initial Diagnosis
Authors: Lee Hae , Yoon Jong , Park Kyu , Lim Jung , Hwang Jin
Published: October 2018

Long-term effects of type 2 diabetes mellitus (T2D) on bone health remain unclear. The objective of this study was to assess the possible association of bone mineral density (BMD) at multiple sites with T2D after correcting for several potential confounders such as age, sex, Tanner stage, and BMI known to affect BMD in adolescents with newly developed T2D. In this cross-sectional study, 17 children and adolescents with T2D and 59 age, sex, and BMI-matched controls were included. All subjects underwent dual-energy X-ray absorptiometry to measure regional and whole-body composition with Lunar Prodigy at the time of initial diagnosis. A BMD Z-score was calculated using data from healthy Korean children and adolescents after adjusting for height-for-age. The mean age of all subjects was 12.9±2.4 years (range, 8.3–18.3 years). BMDht Z-scores for lumbar spine and total body after adjusted for age, sex, BMI SDS, and Tanner stage were not significantly different between patients and controls. However, BMDht Z-scores for femur neck and bone mineral apparent density (BMAD) Z-scores of lumbar spine were significantly lower in T2D patients than those in healthy controls. HOMA-IR or HbA1c was not associated with BMDht Z-scores at multiple sites. BMDht Z-scores at multiple sites except femur neck in adolescents with newly developed T2D were similar to those in obese controls after adjustment for potential confounders.
Elastografía hepática y otras secuencias avanzadas de RM (RM multiparamétrica)
Authors: Domínguez Andrés , Noceti Maximiliano , Fino Daniel , Ariza Pablo
Published: October 2018

La fibrosis es un destino donde convergen variados trastornos hepáticos. Al tratarse de un proceso dinámico y reversible, su detección temprana y una intervención terapéutica oportuna, pueden frenar su progresión. La elastografía por resonancia magnética (ERM), es un método no invasivo con notable eficacia para la valoración del grado de fibrosis hepática. La tendencia actual es combinar esa técnica con secuencias de cuantificación de lípidos y hierro, lo cual permite un abordaje multiparamétrico de los trastornos difusos del hígado.
Geographic smoothing of solar photovoltaic electric power production in the Western USA
Authors: Klima Kelly , Apt Jay , Bandi Mahesh , Happy Paul , Loutan Clyde , Young Russell
Published: October 2018

We examined the geographic smoothing of solar photovoltaic generation from 15 utility-scale plants in California, Nevada, and Arizona and from 19 commercial building installations in California. This is the first comparison of geographic smoothing from utility-scale and building-mounted PV and the first examination of solar PV smoothing in this region. Our research questions were (1) how does geographic smoothing of commercial building rooftop PV compare to that of utility scale PV?, (2) is the geographic smoothing found for utility-scale plants the same for the western US as in India?, and (3) how does the geographic smoothing for PV compare to that of wind? By examining the power output of these generators in the frequency domain, we quantified the smoothing obtained by combining the output of geographically separated plants. We found that utility-scale and commercial rooftop plants exhibited similar geographic smoothing, with 10 combined plants reducing the amplitude of fluctuations at 1 h to 18%–28% of those seen for a single plant. We find that combining a few PV sites together reduces fluctuations, but that the point of quickly diminishing returns is reached after ∼5 sites, and that for all the locations and plant sizes considered, PV does not exhibit as much geographic smoothing as is seen for combining wind plants. We present preliminary theoretical arguments for why geographic smoothing of PV plants is less effective than that for wind plants. The slope of the high-frequency part of the PV power spectrum can at best be geographically smoothed (steepen) to an asymptotic spectrum of f−2. This limit for PV has considerably less smoothing than that for wind's geographic smoothing, shown theoretically and from observed data to be f−2.33.
Radiation diagnostics for plasma current ramp-up and ramp-down research
Authors: Wang Binbin , Wang Shouzhi , Tan Yi , Gao Zhe
Published: October 2018

The plasma current ramp-up and ramp-down are the basic processes in the tokamak operation. In order to research these processes in SUNIST (Sino-UNIted Spherical Tokamak), some diagnostic systems that detect the plasma radiation ranging from hard X-rays to visible light are developed. CdZnTe and silicon drift detectors measure the energy spectrum of hard X-rays and soft X-rays coming from the plasma. A pinhole camera equipped with absolute extended ultraviolet array photodiodes has been installed on the top of SUNIST to observe the radiation power loss and the magneto-hydrodynamic activities with high temporal and spatial resolution. The spectrum of vacuum ultraviolet is acquired by using a CCD camera, and the intensity of the lines can be measured by using a photomultiplier tube with a scintillator. The full spectrum of the visible light can be acquired in every 3 ms, and the intensity of some lines, such as Hα, Hγ, can be measured by filter scopes with high time response. Additionally, a Doppler broadening measurement system is developed to measure the ion temperature of edge plasma.
Temperature and hydrogen diffusion length in hydrogenated amorphous silicon films on glass while scanning with a continuous wave laser at 532 nm wavelength
Authors: Beyer Wolfhard , Andrä Gudrun , Bergmann Joachim , Breuer Uwe , Finger Friedhelm , Gawlik Annett , Haas Stefan , Lambertz Andreas , Maier Florian C. , Nickel Norbert H. , Zastrow Uwe
Published: October 2018

Rapid thermal annealing by, e.g., laser scanning of hydrogenated amorphous silicon (a-Si:H) films is of interest for device improvement and for development of new device structures for solar cell and large area display application. For well controlled annealing of such multilayers, precise knowledge of temperature and/or hydrogen diffusion length in the heated material is required but unavailable so far. In this study, we explore the use of deuterium (D) and hydrogen (H) interdiffusion during laser scanning (employing a continuous wave laser at 532 nm wavelength) to characterize both quantities. The evaluation of temperature from hydrogen diffusion data requires knowledge of the high temperature (T > 500 °C) deuterium-hydrogen (D-H) interdiffusion Arrhenius parameters for which, however, no experimental data exist. Using data based on recent model considerations, we find for laser scanning of single films on glass substrates a broad scale agreement with experimental temperature data obtained by measuring the silicon melting point and with calculated data using a physical model as well as published work. Since D-H interdiffusion measures hydrogen diffusion length and temperature within the silicon films by a memory effect, the method is capable of determining both quantities precisely also in multilayer structures, as is demonstrated for films underneath metal contacts. Several applications are discussed. Employing literature data of laser-induced temperature rise, laser scanning is used to measure the H diffusion coefficient at T > 500 °C in a-Si:H. The model-based high temperature hydrogen diffusion parameters are confirmed with important implications for the understanding of hydrogen diffusion in the amorphous silicon material.
In-plane thermal diffusivity measurement of thin plates by the transient fin method
Authors: Jannot Yves , Degiovanni Alain , Aubert Arthur , Lechleiter François
Published: October 2018

The transient fin method has mainly been used for the measurement of in-plane thermal diffusivity of rather highly diffusive materials available under the form of thin plates. This paper presents an extension of the method to low diffusivity materials such as plastics. A new analytical model is used in the real space, avoiding to make a Laplace transform of experimental temperatures recordings that may be inaccurate. Experiments carried on two materials under gas pressure varying from 10−2 mbar to 1 bar show the great influence of heat conduction in the air surrounding the sample, leading to estimation errors that can reach 30% at atmospheric pressure. The experimental results also show that accurate measurements can be achieved if the pressure is lower than 10−2 mbar.
Performance of fast-ion loss diagnostic on EAST
Authors: Wu C. R. , Huang J. , Chang J. F. , Zhang J. , Zhou R. J. , Xu Z. , Gao W. , Isobe M. , Ogawa K. , Lin S. Y. , Hu L. Q. , Li J. G. ,   EAST Team
Published: October 2018

The scintillator-based detector for fast-ion loss measurements has been installed on EAST. To obtain high temporal resolution for fast-ion loss diagnostics, fast photomultiplier tube systems have been developed which can supply the complementary measurements to the previous image system with good energy and pitch resolution by using a CCD camera. By applying the rotatable platform, the prompt losses of beam-ions can be measured in normal and reverse magnetic field. The thick-target bremsstrahlung occurring in the stainless steel shield with energetic electrons can produce X-rays, which will strike on the scintillator based detector. To understand this interference on fast-ion loss signals, the effects of energetic electrons on the scintillator-based detector are studied, including runaway electrons in the plasma ramping-up phase and fast electrons accelerated by the lower hybrid wave.
Response to “Comment on ‘Soliton solutions and chaotic motion of the extended Zakharov-Kuznetsov equations in a magnetized two-ion-temperature dusty plasma’” [Phys. Plasmas 25, 104701 (2018)]
Authors: Zhen Hui-Ling , Tian Bo , Wang Yu-Feng , Sun Wen-Rong , Liu Li-Cai
Published: October 2018

On our previous soliton solutions [H. L. Zhen et al., Phys. Plasmas 21, 073709 (2014)] of an extended Zakharov-Kuznetsov equation, El-Tantawy and Wazwaz [Phys. Plasmas 25, 104701 (2018)] have commented that there exists another soliton solution without any constraint for the parameters. In this Reply, we first state the correctness of our previous solutions, and then, we point out the difference between the two solutions: one is from our previous paper [H. L. Zhen et al., Phys. Plasmas 21, 073709 (2014)] and the other is from the comment by El-Tantawy and Wazwaz [Phys. Plasmas 25, 104701 (2018)]. Meanwhile, we also investigate the connections between our work and some recent literature studies.
Time-resolved and multiple-angle Thomson scattering on gas-puff Z-Pinch plasmas at pinch time
Authors: Rocco Sophia V. R. , Banasek Jacob T. , Potter William M. , Hammer David A.
Published: October 2018

A 526.5 nm Thomson scattering diagnostic laser enables probing of the plasma conditions of neon gas-puff z-pinch implosions with temporal resolution. Splitting the laser into two 2.5 J pulses, both 2.3 ns in duration and separated by 4 ns, allows observation of sub-nanosecond time-resolved spectra for a total time of 7 ns. Collection optics were set at 90° and 30° to the laser, observing the same on-axis scattering volume with a radial extent of 0.4 mm. The spectra from both angles were collected by using the same streak camera, using a coupling system that allowed us to obtain temporal, spectral, and angular resolution in the same image. By comparing the ion-acoustic spectra from the two angles, we determined electron temperature and a range of possible electron densities. Measurements made in the 1-3 ns period before pinch time show best fit (determined by a least-squares method) electron densities of around 2 × 1019 cm−3, increasing to 1.5 × 1020 cm−3 in the 3 ns following the start of the x-ray burst (t = 0 ns) from the pinch. The electron temperature increases from 300 eV to 500 eV at t = 0 ns before decreasing to below 300 eV after pinch time. With the present parameters (probe beam, collection angles, and electron temperature and density), this diagnostic method is too insensitive to electron density to provide more than a constraint on that parameter. Plasma regimes in which this technique could determine electron density with some precision are calculated.
Demonstration of confocal laser induced fluorescence at long focal lengths
Authors: Henriquez Miguel F. , Thompson Derek S. , Jemiolo Andrew J. , Scime Earl E.
Published: October 2018

We add a collection path obscuration to a confocal telescope and confirm theoretical predictions of significant improvement in the longitudinal spatial localization. The improvements of spatial localization permitted an extension of the confocal telescope’s focal length from 150 mm to 500 mm. At this longer focal length, millimeter-scale spatial localization is confirmed by comparing radial profiles of metastable state density obtained via confocal and conventional optical arrangements in a helicon source. The long focal length arrangement enables the measurement of argon neutral velocity distribution functions in the conventionally inaccessible region under a helicon source antenna.
Fundamental understanding of chemical processes in extreme ultraviolet resist materials
Authors: Kostko Oleg , Xu Bo , Ahmed Musahid , Slaughter Daniel S. , Ogletree D. Frank , Closser Kristina D. , Prendergast David G. , Naulleau Patrick , Olynick Deirdre L. , Ashby Paul D. , Liu Yi , Hinsberg William D. , Wallraff Gregory M.
Published: October 2018

New photoresists are needed to advance extreme ultraviolet (EUV) lithography. The tailored design of efficient photoresists is enabled by a fundamental understanding of EUV induced chemistry. Processes that occur in the resist film after absorption of an EUV photon are discussed, and a new approach to study these processes on a fundamental level is described. The processes of photoabsorption, electron emission, and molecular fragmentation were studied experimentally in the gas-phase on analogs of the monomer units employed in chemically amplified EUV resists. To demonstrate the dependence of the EUV absorption cross section on selective light harvesting substituents, halogenated methylphenols were characterized employing the following techniques. Photoelectron spectroscopy was utilized to investigate kinetic energies and yield of electrons emitted by a molecule. The emission of Auger electrons was detected following photoionization in the case of iodo-methylphenol. Mass-spectrometry was used to deduce the molecular fragmentation pathways following electron emission and atomic relaxation. To gain insight on the interaction of emitted electrons with neutral molecules in a condensed film, the fragmentation pattern of neutral gas-phase molecules, interacting with an electron beam, was studied and observed to be similar to EUV photon fragmentation. Below the ionization threshold, electrons were confirmed to dissociate iodo-methylphenol by resonant electron attachment.
Energy transfer in elastic collisions between electrons and trapped ions
Authors: Kłosowski Łukasz , Piwiński Mariusz
Published: October 2018

Heating of trapped ion clouds by interactions with free electrons crossing the trapping potential was observed. A model describing such a process was proposed and discussed. The presented approach predicts two effects: pushing and heating of the ions' ensemble by electrons. The former was found to be too weak for observation; however, the latter was investigated experimentally. For comparison between experimental results and theoretical predictions, molecular dynamics simulations for various ion ensembles in various temperatures were performed to determine the dependence between ion cloud geometry and its temperature. A heating rate coefficient was defined and determined together with temperatures of ion clouds bombarded with electrons. Good correlation between the two quantities was found, which agrees with the proposed model.
Frequency measurements and self-broadening of sub-Doppler transitions in the v1 + v3 band of C2H2
Authors: Twagirayezu Sylvestre , Hall Gregory E. , Sears Trevor J.
Published: October 2018

Frequency comb-referenced measurements of sub-Doppler laser saturation dip absorption lines in the v1 + v3 band of acetylene near 1.5 μm are reported. These measurements include transitions involving higher rotational levels than previously frequency measured in this band. The accuracy of the measured frequencies is typically better than 10 kHz. Measurements of the observed sub-Doppler line widths as a function of pressure showed that the self-pressure-broadening coefficients are about 3.5 times larger than those derived from conventional pressure broadening of unsaturated Doppler-limited spectra. This is attributed to the contribution of velocity-changing collisions to the total dephasing rate in the low pressure sub-Doppler measurements. At higher pressures, when the homogeneous broadening becomes comparable to the typical Doppler shift per elastic collision, the velocity changing collisions cease to contribute significantly to the incremental pressure broadening. A time-dependent soft collision model is developed to illustrate the transition between low and high pressure regimes of sub-Doppler pressure-broadening.
Perpendicular magnetic anisotropy in bulk and thin-film CuMnAs for antiferromagnetic memory applications
Authors: Zhuravlev I. A. , Adhikari A. , Belashchenko K. D.
Published: October 2018

CuMnAs with perpendicular magnetic anisotropy is proposed as an active material for antiferromagnetic memory. Information can be stored in the antiferromagnetic domain state, while writing and readout can rely on the existence of surface magnetization. It is predicted, based on first-principles calculations, that easy-axis anisotropy can be achieved in bulk CuMnAs by substituting a few percent of As atoms by Ge, Si, Al, or B. This effect is attributed to the changing occupation of certain electronic bands near the Fermi level induced by hole doping. The calculated temperature dependence of the magnetic anisotropy does not exhibit any anomalies. Thin CuMnAs(001) films are also predicted to have perpendicular magnetic anisotropy.
Adhesion of carbon nanotubes on elastic substrates with finite thickness
Authors: Yuan Xuebo , Wang Youshan
Published: October 2018

How carbon nanotubes (CNTs) interact with substrates is fundamental for understanding their physical properties. In existing theoretical and modeling studies, the substrates are considered to be rigid with semi-infinite thickness. In this work, the effects of finite substrate thickness and elasticity are analyzed theoretically and numerically for free boundary conditions. Based on the energy-variational approach, considering the interfacial van der Waals interactions and bending strain energies stored in CNTs and substrates, the governing equations and boundary conditions are derived analytically. The theoretical predictions are in reasonable agreement with the results of molecular dynamics simulations. When the substrate is sufficiently thick, the results of the present theoretical model are entirely consistent with previous models for the infinite-thickness substrate. However, for relatively thin substrates, the effect of substrate thickness is significant due to the geometric large deformation. Three stable adhesive states (initial non-adhesive, partially adhesive, and fully wrapping states) can be achieved, dependent on the substrate thickness, the number of CNT walls, and the interfacial adhesion work. The stability of adhesive configurations is explored by analyzing the energy variations corresponding to the adhesive deformation. We show that there exist several modes of energy variations, depending on the adhesion work and the substrate-CNT bending stiffness ratio, which exhibit linear and nonlinear influences, respectively. Our results could serve as guidelines to design CNT-on-substrate systems.
Comparisons of dynamical characteristics of a 5 MW floating wind turbine supported by a spar-buoy and a semi-submersible using model testing methods
Authors: Chen Jiahao , Hu Zhiqiang , Duan Fei
Published: October 2018

Development of floating offshore wind turbine technology is in need of more scaled model tests to investigate its dynamical characteristics. This paper presents the model testing investigations of a spar-buoy and semi-submersible floating wind turbines, and conducts a series of comparisons on the experimental results of the two floating wind turbines. It is found that the spar-buoy floating wind turbine is more sensitive to wind loading and has larger amplitudes of platform motion in wind only cases, especially for the yaw motion. By contrast, the semi-submersible floating wind turbine is more sensitive to wave loading, especially for the second order difference-frequency wave loading. In addition, the dynamic responses of the two floating wind turbines are both influenced by the current flow. Compared to the semi-submersible floating wind turbine, the more regular “figure-eight” surge-sway trajectory is observed in the spar-buoy floating wind turbines, showing the influence from vortex-induced-motion. This paper provides more valuable experimental details and results to the scientific community with regard to the spar-buoy and semi-submersible floating wind turbines. Moreover, the comparison of the dynamic behaviours of the two floating wind turbines in various conditions helps to understand the characteristics and mechanism about the floating wind turbine technology.
Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework
Authors: Sowa Jakub K. , Mol Jan A. , Briggs G. Andrew D. , Gauger Erik M.
Published: October 2018

Charge transport through molecular junctions is often described either as a purely coherent or a purely classical phenomenon, and described using the Landauer–Büttiker formalism or Marcus theory (MT), respectively. Using a generalised quantum master equation, we here derive an expression for current through a molecular junction modelled as a single electronic level coupled with a collection of thermalised vibrational modes. We demonstrate that the aforementioned theoretical approaches can be viewed as two limiting cases of this more general expression and present a series of approximations of this result valid at higher temperatures. We find that MT is often insufficient in describing the molecular charge transport characteristics and gives rise to a number of artefacts, especially at lower temperatures. Alternative expressions, retaining its mathematical simplicity, but rectifying those shortcomings, are suggested. In particular, we show how lifetime broadening can be consistently incorporated into MT, and we derive a low-temperature correction to the semi-classical Marcus hopping rates. Our results are applied to examples building on phenomenological as well as microscopically motivated electron-vibrational coupling. We expect them to be particularly useful in experimental studies of charge transport through single-molecule junctions as well as self-assembled monolayers.
Direct observation of dislocation structure evolution in SRF cavity niobium using electron channeling contrast imaging
Authors: Wang M. , Kang D. , Bieler T. R.
Published: October 2018

Two major goals of superconducting radio frequency cavity research and development are achieving higher accelerating gradient and gaining the highest quality factor, a measure of efficiency. However, the consistent improvement of these performance metrics is restricted by many factors, one of which is microstructural defects, such as dislocation substructures within the material. In this work, dislocation evolution is compared in four samples extracted from a 2.8 mm thick large-grain niobium slice, with tensile axes chosen to generate specific dislocation structures during subsequent deformation. The four samples are (1) as-extracted, (2) extracted and annealed, (3) extracted and then deformed to 40% tensile strain, and (4) extracted, annealed at 800 °C 2 h, and then deformed to 40% strain. Electron channeling contrast imaging was performed on all samples to characterize initial dislocation density and dislocation structure evolution due to annealing and deformation, and related to the mechanical behavior observed in stress-strain curves. A fundamental understanding of dislocation evolution in niobium is necessary to develop computational models to simulate cavity forming, which could enable new processing methods for cavity fabrication to be identified that could lead to improved performance.
Manipulation and generation of the spatially ultra-compact and high quality THz beam
Authors: Zhang Xiao-Bo , Qiao Xin , Cheng Li-Hong , Zhang Ai-Xia , Xue Ju-Kui
Published: October 2018

The generation of a spatially ultra-compact and high quality terahertz (THz) beam has been a challenging issue at present for advancing the THz technology. Here, we demonstrate an efficient scheme from the laser-plasma interaction in a spatially modulated magnetized plasma to control the THz beam. An analytical THz radiation field and the two-dimensional particle-in-cell simulations based on the scheme are carried out. The spatial distribution, the intensity, and the polarization of the THz beam are highly modulated and controlled by the laser field, external magnetic field, and self-generated plasma channel. A spatially modulated ultra-compact and high-brightness THz beam with the multiple THz field distribution patterns is generated. This scheme opens a practical and economical path to develop the THz technology in various fields.
Ion acoustic turbulence driven by return current leads to hot electrons in laser-produced plasma
Authors: Bychenkov V. Yu.
Published: October 2018

The instability of ion acoustic waves due to the return current driven by an electron heat flux is a source of ion acoustic turbulence (IAT), which provides electromagnetic wave conversion into Langmuir waves at a near-critical density in inertial confinement fusion plasmas. The Langmuir waves triggered by IAT produce hot electrons. We formulate a theoretical model of hot-electron generation by these Langmuir waves and analyze it qualitatively. We show that IAT-driven hot electrons are generated in the backward direction and, therefore, preheat the target core because of the electron refluxing in the coronal plasma back toward the solid target.
Existence of vortices in nonlinear optics
Authors: Chen Xiao , Chen Shouxin , Wang Shu
Published: October 2018

Optical propagation in nonlinear media and the formation of optical vortices as dark holes have been intensively studied in modern optical physics. In this paper, we prove the existence of different types of stationary vortex wave solutions of a general class for nonlinear Schrödinger equations. First, we prove the existence of positive radially symmetric solutions by solving a constrained minimization problem and give some lower estimate of the wave propagation constant. We then use a min-max technique to prove the existence of additional non-trivial solutions which arise as saddle-points of a corresponding indefinite action functional.

At the request of the Editor-in-Chief and the authors this articles has been retracted. Due to an irreparable error in the arguments, the main results are not correct.
Pervasive tertiary structure in the dengue virus RNA genome
Authors: Dethoff Elizabeth A. , Boerneke Mark A. , Gokhale Nandan S. , Muhire Brejnev M. , Martin Darren P. , Sacco Matthew T. , McFadden Michael J. , Weinstein Jules B. , Messer William B. , Horner Stacy M. , Weeks Kevin M.
Published: October 2018

Significance

RNA viruses usurp and reprogram host cells using short RNA genomes. RNA viruses encode the information required for their replication in both their primary sequences and higher-order structures formed when the RNA genome strand folds back on itself, but the extent of higher-order structure has remained unclear. We use a new high-throughput RNA structure probing technology to identify RNA regions with tertiary folds and discover that roughly one-third of the dengue virus RNA genome forms higher-order interactions, many in regions functionally important for replication. This work suggests that tertiary structure elements might be common in large RNAs, and that these regions might contain pockets targetable by small molecules in the design of antiviral therapeutics.
Specificity landscapes unmask submaximal binding site preferences of transcription factors
Authors: Bhimsaria Devesh , Rodríguez-Martínez José A. , Pan Junkun , Roston Daniel , Korkmaz Elif Nihal , Cui Qiang , Ramanathan Parameswaran , Ansari Aseem Z.
Published: October 2018

Significance

Several experimental platforms and computational methods have been developed to identify DNA binding sites of over 1,000 transcription factors. Often, high-affinity (maximal) binding sites are reported as consensus motifs. Differences between experimental platforms contribute to uncertainty in ascribing binding to submaximal sites. However, biological studies emphasize the importance of submaximal binding sites in shaping regulatory functions of transcription factors. To bridge this gap, we developed Differential Specificity and Energy Landscapes to unmask differences between experimental and computational methods as well as capture distinct submaximal binding site preferences of transcription factors. Our results suggest that subtle variation in protein structure can allosterically confer homolog-specific differences in binding to submaximal affinity sites.
Contexts of use of a rotated palms gesture among Syuba (Kagate) speakers in Nepal
Authors: Gawne Lauren
Published: October 2018

In this paper I examine the use of the ‘rotated palms’ gesture family among speakers of Syuba (Tibeto-Burman, Nepal), as recorded in a video corpus documenting this language. In this family of gestures one or both forearms are rotated to a supine (‘palm up’) position, each hand with thumb and forefinger extended and the other fingers, in varying degrees, flexed toward the palm. When used independently from speech this gesture tends to be performed in a relatively consistent manner, and is recognised as an interrogative gesture throughout India and Nepal. In this use it can be considered an emblem. When used with speech it shows more variation, but can still be used to indicate the interrogative nature of what is said, even when the speech may not indicate interrogativity in its linguistic construction. I analyse the form and function of this gesture in Syuba and argue that there are a number distinct functions relating to interrogativity. These can therefore be considered as a family of gestures. This research lays the groundwork for a better understanding of this common family of gestures across the South Asian area, and beyond.