bluuebunny/crossref_metadata_2025 huggingface dataset:
Active/reactive power control of photovoltaic grid‐tied inverters with peak current limitation and zero active power oscillation during unbalanced voltage sags
Authors: Dehghani Tafti Hossein , Maswood Ali Iftekhar , Konstantinou Georgios , Pou Josep , Acuna Pablo
Published: January 2018

This paper proposes an analytical expression for the calculation of active and reactive power references of a grid‐tied inverter, which limits the peak current of the inverter during voltage sags. The key novelty is that the active/reactive power references are analytically calculated based on the dc‐link voltage and grid codes, while they do not depend on the implemented current reference calculation algorithm and, as a general formulation, can be implemented in combination with various current reference calculation algorithms. Furthermore, based on the inverter nominal current and the injected reactive power to the grid during voltage sags, an analytical algorithm is introduced for the calculation of the active power reference, which can be extracted from PV strings. The proposed algorithm ensures that the maximum current capability of the inverter is used for the enhancement of the grid voltages during voltage sags, while it always complies with the reactive power injection requirement of grid codes and avoids increasing the dc‐link voltage excessively. An unbalanced current injection algorithm is also applied for the grid‐tied inverter which results in zero active power oscillation. Experimental results of a grid‐connected 3.3‐kVA, three‐level, neutral‐point‐clamped inverter laboratory prototype are presented to demonstrate the effectiveness of the proposed controller.
Phase angle‐based PC technique for islanding detection of distributed generations
Authors: Muda Harikrishna , Jena Premalata
Published: January 2018

The phase angle‐based principal component (PC) technique for islanding detection of distributed generations (DGs) is proposed. The phase angle between the positive‐sequence components of voltage and current is derived at the DG terminal and used as an input feature vector for the PC technique to identify the islanding situation (IS). The change in phase angle is prominent for both ISs and non‐ISs (NISs). By exploiting this change in phase angle, PCs are computed to discriminate between ISs and NISs. The proposed technique is evaluated using data simulated with a real‐time digital simulator for IEEE 13‐bus microgrids. Critical issues such as a perfect power match IS, different scenarios of microgrids having a synchronous generator, doubly fed induction wind generator, photovoltaic with various control strategies and battery energy storage systems are addressed during performance evaluation of the proposed technique. It is found that the technique identifies the IS under low active and reactive power mismatches and hence overcomes the non‐detection zone problem. All NISs such as the fault type, DG tripping and feeder disconnection in the presence of multiple DGs are considered. It is noteworthy to mention that the proposed technique discriminates ISs and NISs within a cycle from the inception point.
Semidiurnal thermal tides in asynchronously rotating hot Jupiters
Authors: Auclair-Desrotour P. , Leconte J.
Published: January 2018

Context. Thermal tides can torque the atmosphere of hot Jupiters into asynchronous rotation, while these planets are usually assumed to be locked into spin-orbit synchronization with their host star.

Aims. In this work, our goal is to characterize the tidal response of a rotating hot Jupiter to the tidal semidiurnal thermal forcing of its host star by identifying the structure of tidal waves responsible for variation of mass distribution, their dependence on the tidal frequency, and their ability to generate strong zonal flows.

Methods. We develop an ab initio global modelling that generalizes the early approach of Arras & Socrates (2010, ApJ, 714, 1) to rotating and non-adiabatic planets. We analytically derive the torque exerted on the body and the associated timescales of evolution, as well as the equilibrium tidal response of the atmosphere in the zero-frequency limit. Finally, we numerically integrate the equations of thermal tides for three cases, including dissipation and rotation step by step.

Results. The resonances associated with tidally generated gravito-inertial waves significantly amplify the resulting tidal torque in the range 1–30 days. This torque can globally drive the atmosphere into asynchronous rotation, as its sign depends on the tidal frequency. The resonant behaviour of the tidal response is enhanced by rotation, which couples the forcing to several Hough modes in the general case, while the radiative cooling tends to regularize it and diminish its amplitude.
The VLT/MUSE view of the central galaxy in Abell 2052
Authors: Balmaverde Barbara , Capetti Alessandro , Marconi Alessandro , Venturi Giacomo
Published: January 2018

We report observations of the radio galaxy 3C 317 (at z = 0.0345) located at the center of the Abell cluster A2052, obtained with the VLT/MUSE integral field spectrograph. The Chandra images of this cluster show cavities in the X-ray emitting gas, which were produced by the expansion of the radio lobes inflated by the active galactic nucleus (AGN). Our exquisite MUSE data show with unprecedented detail the complex network of line emitting filaments enshrouding the northern X-ray cavity. We do not detect any emission lines from the southern cavity, with a luminosity asymmetry between the two regions higher than ~75. The emission lines produced by the warm phase of the interstellar medium (WIM) enable us to obtain unique information on the properties of the emitting gas. We find dense gas (up to 270 cm−3) that makes up part of a global quasi spherical outflow that is driven by the radio source, and obtain a direct estimate of the expansion velocity of the cavities (265 km s−1). The emission lines diagnostic rules out ionization from the AGN or from star-forming regions, suggesting instead ionization from slow shocks or from cosmic rays. The striking asymmetric line emission observed between the two cavities contrasts with the less pronounced differences between the north and south sides in the hot gas; this represents a significant new ingredient for our understanding of the process of the exchange of energy between the relativistic plasma and the external medium. We conclude that the expanding radio lobes displace the hot tenuous phase of the interstellar medium (ISM), but also impact the colder and denser ISM phases. These results show the effects of the AGN on its host and the importance of radio mode feedback.
The effects of cathode electrodeposited polymer film on the long vacuum gap breakdown
Authors: Zhang Yu , Su Jiancang , Qiu Xudong , Li Rui , Zhao Liang , Yu Binxiong , Cheng Jie , Zeng Bo , Xu Xiudong
Published: January 2018

Vacuum surface discharge is one of the most important issues for vacuum insulation. In this paper, a method for breakdown field strength enhancement of long vacuum gap is put forward, through depositing polymer dielectric coating on the electrode surface. The physical mechanism that the polymer film changes the electrode surface state is analyzed. After a layer of polymer film is deposited on the electrode surface, the decreased surface field strength and improved micro-surface state both help to suppress the field electron emission from the cathode. The technique of cathode electrodeposition for high polymers such as epoxy resin (ER), epoxy acrylate (EA), polyimide (PI) and poly(ether-ether-ketone) (PEEK) was explored, and the thickness of the electrodeposited coating can reach 20–50 µm. The effects of the electrodeposited polymer coatings of electrodes on the 2.5 cm vacuum gap breakdown were studied under a high-voltage vacuum experiment platform. Experimental results showed that when ER, EA and PEEK coatings with thickness of 25–45 µm were respectively electrodeposited on the 95 cm2 plate cathode, the initial-breakdown field strengths of the 2.5 cm vacuum gap were enhanced by 20.7%–22.4%. The enhancement of the initial-breakdown field strength was restricted by the coating defects, grain boundary defects on the cathode surface, and the micro-triple-point emission after the fusing of some local coating points due to the electron bombardments.
Future Measurements of the Nucleon Elastic Electromagnetic Form Factors at Jefferson Lab
Authors: Gilfoyle Gerard
Published: January 2018

The elastic, electromagnetic form factors are fundamental observables that describe the internal structure of protons, neutrons, and atomic nuclei. Jefferson Lab in the United States has completed the 12 GeV Upgrade that will open new opportunities to study the form factors. A campaign to measure all four nucleon form factors (electric and magnetic ones for both proton and neutron) has been approved consisting of seven experiments in Halls A, B, and C. The increased energy of the electron beam will extend the range of precision measurements to higher Q2 for all four form factors together. This combination of measurements will allow for the decomposition of the results into their quark components and guide the development of a QCD-based understanding of nuclei in the non-perturbative regime. I will present more details on the 12 GeV Upgrade, the methods used to measure the form factors, and what we may learn.
The Charm and Beauty of Strong Interactions
Authors: El-Bennich Bruno
Published: January 2018

We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.
Nucleon Spectroscopy with CLAS
Authors: Strauch Steffen
Published: January 2018

Meson photoproduction is an important tool in the study of nucleon resonances. The spectrum of broad and overlapping nucleon excitations can be greatly clarified by use of polarization observables. The N* program at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS) includes experimental studies with linearly- and circularly-polarized tagged-photon beams, longitudinally- and transversely-polarized nucleon targets, and recoil polarizations. Selected results from these experimental studies will be presented.
Experimental overview of correlations in small collision systems A brief history
Authors: Mohapatra Soumya
Published: January 2018

The azimuthal anisotropies of particle yields observed in relativistic heavy ion collisions have been traditionally considered as a strong evidence of the formation of a deconfined quark-gluon plasma in these collisions. However multiple recent measurements in pp and p/D/He+A collisions show similar features as those observed in heavy ion collisions, indicating the possibility of the production of such a deconfined medium in smaller collision systems. This paper presents a comprehensive summary of such measurements in small systems. It includes measurements of identified and inclusive two-particle correlations in ΔΦ and Δη, with different procedures used to subtract the dijet contributions, as well as measurements of multi-particle cumulants cn{2 - 8}. The traditional cumulant measurements confirm presence of collective phenomena in p+A collisions, but are biased by non-flow correlations and are not able to provide evidence for collectivity in pp collisions. To address this, a new subevent cumulant method that further suppresses the contribution non-flow effects was developed, whose measurements are also discussed.
Collectivity in small systems - Initial state vs. final state effects
Authors: Greif Moritz , Greiner Carsten , Schenke Björn , Schlichting Sören , Xu Zhe
Published: January 2018

Observations of long rang azimuthal correlations in small collision systems (p+p/A) have triggered an enormous excitement in the heavy-ion community. However, it is presently unclear to what extent the experimentally observed correlations should be attributed to initial state momentum correlations and/or the final state response to the initial state geometry. We discuss how a consistent theoretical description of the nonequilibrium dynamics is important to address both effects within a unified framework and present first results from weakly coupled non-equilibrium simulations in [1] to quantify the relative importance of initial state and final state effects based on theoretical calculations.
Retrospektiver Vergleich der Wirbelkörperaufrichtung nach Ballonkyphoplastie vs. Radiofrequenzkyphoplastie
Authors: Palm Hans-Georg , Steinbach Mario , Lang Patricia , Hackenbroch Carsten , Friemert Benedikt , Riesner Hans-Joachim
Published: January 2018

Hintergrund Neben schmerztherapeutischer Wirkung zielt die Kyphoplastie auf eine Aufrichtung osteoporotisch frakturierter Wirbelkörper (WK) ab. Ein neueres Verfahren ist die Radiofrequenzkyphoplastie (RFK). Unklar ist, wie gut sich mit dieser Methodik im Vergleich zur älteren Ballonkyphoplastie (BKP) wieder eine anatomische WK-Aufrichtung erreichen lässt. Ziel unserer retrospektiven Studie war daher der Vergleich beider Verfahren bez. der Grund-/Deckplattenwinkel post- vs. präoperativ.

Patienten und Methoden Anhand prä- und postoperativer Stehend-Röntgenaufnahmen wurden bei 87 Probanden (46 BKP und 41 RFK) bzw. 142 kyphoplastierten WK (67 BKP und 75 RFK) die Winkel von Grund- zu Deckplatte bestimmt. Hauptzielgröße war der Grad der Aufrichtung (Δpost−prä) bei der BKP vs. RFK. Außerdem wurden für die Bestimmung des sagittalen Alignments die angrenzenden gesunden Segmente ausgemessen.

Ergebnisse Sowohl bei der BKP (BKPprä: 11,5 ± 6,0°, BKPpost: 6,2 ± 4,6°, p < 0,001) als auch RFK (RFKprä: 9,9 ± 6,2°, RFKpost: 6,3 ± 4,4°, p < 0,001) kam es zu einer signifikanten Aufrichtung. Es zeigte sich im Verfahrensvergleich aber eine bessere Aufrichtung in der Gruppe BKP im Vergleich zur RFK (Δpost−prä BKP: − 5,3 ± 4,4°, Δpost−prä RFK: − 3,6 ± 4,4°, p = 0,03). Kein Verfahren führte aber im umgebenden Wirbelsäulensegment zu einer signifikanten Änderung des Winkels (Segment BKPprä: 13,8 ± 8,0°, Segment BKPpost: 12,5 ± 9,2°, p = 0,638; Segment RFKprä: 18,8 ± 14,3°, Segment RFKpost: 15,0 ± 13,2°, p = 0,330).

Schlussfolgerung Es konnte eine signifikant bessere Aufrichtung des Kyphosewinkels durch die BKP erreicht werden, wobei beide Verfahren für sich betrachtet zu einer hochsignifikanten Verbesserung des Kyphosewinkels geführt haben. Im angrenzenden Wirbelsäulensegment ist die Auswirkung auf den messbaren Winkel nicht signifikant ausgeprägt, sodass das Alignment durch den Eingriff tendenziell weniger beeinflusst wird.
Tarsusknickung („Tarsal Kink“): Pathognomonische Präsentation und Therapie einer seltenen kongenitalen Oberlidfehlbildung
Authors: Schaudig Ulrich , Keserü Matthias
Published: January 2018

Hintergrund und Ziel Präsentation eines seltenen, aber typisch verlaufenden, kongenitalen Krankheitsbilds, das bei Kenntnis der pathognomonischen Zeichen unmittelbar erkannt und therapiert werden kann. Die angeborene Tarsusknickung führt zu einer Fehlstellung des Oberlids mit Entropium, die nicht übersehen werden darf, da sie unbehandelt zu einer ulzerierenden Keratitis führt.

Fall Nach Zangenentbindung bestand bei einem sonst gesunden Neugeborenen eine ausgeprägte einseitige eitrige Sekretion mit Blepharospasmus.

Differenzialdiagnose Dacryocystitis neonatorum, Neugeborenengonoblenorrhö, kongenitales Oberlidentropium mit Hornhautulkus, Tarsusknickung.

Untersuchung Bei wachem Zustand war eine vollständige Untersuchung nicht möglich. Es bestand das pathognomonische Zeichen „fehlender“ Wimpern durch die Inversion der Lidkante. Bei der Narkoseuntersuchung zeigte sich eine Tarsusknickung mit vollständigem Oberlidentropium sowie ein Hornhautulkus.

Behandlung In der Literatur werden verschiedene Methoden angegeben, um diese seltene Fehlanlage zu korrigieren. Allen gemeinsam ist die Stärkung der anterioren Lamelle, um den Knick auszugleichen. Nach Lidspaltung, Repositionierung des Tarsus und Sicherung durch Fixationsnähte heilte das Hornhautulkus rasch und folgenlos ab, Lidschluss und Lidkontur waren normal und seitengleich.

Fazit Das pathognomonische Zeichen des kongenitalen Oberlidentropiums mit Tarsusknickung ist die komplette Inversion des Lidrands, was den Eindruck „fehlender“ Wimpern vermittelt, begleitet von Blepharospasmus und im weiteren Verlauf eitriger Sekretion und Hornhautulkus. Das Krankheitsbild darf nicht übersehen werden, nur die sofortige Korrektur kann eine schwere Schädigung verhindern.
A theoretical and practical clarification on the calculation of reflection loss for microwave absorbing materials
Authors: Liu Ying , Zhao Kun , Drew Michael G. B. , Liu Yue
Published: January 2018

Reflection loss is usually calculated and reported as a function of the thickness of microwave absorption material. However, misleading results are often obtained since the principles imbedded in the popular methods contradict the fundamental facts that electromagnetic waves cannot be reflected in a uniform material except when there is an interface and that there are important differences between the concepts of characteristic impedance and input impedance. In this paper, these inconsistencies have been analyzed theoretically and corrections provided. The problems with the calculations indicate a gap between the background knowledge of material scientists and microwave engineers and for that reason a concise review of transmission line theory is provided along with the mathematical background needed for a deeper understanding of the theory of reflection loss. The expressions of gradient, divergence, Laplacian, and curl operators in a general orthogonal coordinate system have been presented including the concept of reciprocal vectors. Gauss’s and Stokes’s theorems have been related to Green’s theorem in a novel way.
Electrical characterization of ALD HfO2 high-k dielectrics on (2¯01) β-Ga2O3
Authors: Shahin David I. , Tadjer Marko J. , Wheeler Virginia D. , Koehler Andrew D. , Anderson Travis J. , Eddy Charles R. , Christou Aris
Published: January 2018

The electrical quality of HfO2 dielectrics grown by thermal atomic layer deposition at 175 °C on n-type (2¯01) β-Ga2O3 has been studied through capacitance- and current-voltage measurements on metal-oxide-semiconductor capacitors. These capacitors exhibited excellent electrical characteristics, including dual-sweep capacitance-voltage curves with low hysteresis and stretch-out and a frequency-stable dielectric constant of k∼14 when measured between 10 kHz and 1 MHz. The C-V curves exhibited a uniform and repeatable +1.05 V shift relative to the ideal case when swept from 3.5 to −5 V, yielding positively measured flatband (+2.15 V) and threshold (+1.05 V) voltages that may be useful for normally off n-channel Ga2O3 devices. Using the Terman method, an average interface trap density of 1.3 × 1011 cm−2·eV−1 was obtained between 0.2 and 0.6 eV below the conduction band edge. The forward bias current-voltage characteristic was successfully fitted to the Fowler-Nordheim tunneling model at a field strength of 5 MV/cm, allowing an extraction of a 1.3 eV conduction band offset between HfO2 and Ga2O3, which matches the value previously determined from x-ray photoelectron spectroscopy. However, a temperature dependence in the leakage current was observed. These results suggest that HfO2 is an appealing dielectric for Ga2O3 device applications.
General-purpose readout electronics for white neutron source at China Spallation Neutron Source
Authors: Wang Q. , Cao P. , Qi X. , Yu T. , Ji X. , Xie L. , An Q.
Published: January 2018

The under-construction White Neutron Source (WNS) at China Spallation Neutron Source is a facility for accurate measurements of neutron-induced cross section. Seven spectrometers are planned at WNS. As the physical objectives of each spectrometer are different, the requirements for readout electronics are not the same. In order to simplify the development of the readout electronics, this paper presents a general method for detector signal readout. This method has advantages of expansibility and flexibility, which makes it adaptable to most detectors at WNS. In the WNS general-purpose readout electronics, signals from any kinds of detectors are conditioned by a dedicated signal conditioning module corresponding to this detector, and then digitized by a common waveform digitizer with high speed and high precision (1 GSPS at 12-bit) to obtain the full waveform data. The waveform digitizer uses a field programmable gate array chip to process the data stream and trigger information in real time. PXI Express platform is used to support the functionalities of data readout, clock distribution, and trigger information exchange between digitizers and trigger modules. Test results show that the performance of the WNS general-purpose readout electronics can meet the requirements of the WNS spectrometers.
Optical functions and critical points of dilute bismide alloys studied by spectroscopic ellipsometry
Authors: Bushell Z. L. , Joseph R. M. , Nattermann L. , Ludewig P. , Volz K. , Keddie J. L. , Sweeney S. J.
Published: January 2018

Critical point transition energies and optical functions of the novel GaAs-based dilute bismide alloys GaAsBi, GaNAsBi, and GaPAsBi were determined using spectroscopic ellipsometry. The ellipsometry data were analyzed using a parameterized semiconductor model to represent the dielectric function of the alloys as the sum of Gaussian oscillators centered on critical points in the band structure, and from this extracting the energies of those critical points. The band gap and spin-orbit splitting were measured for samples for a range of alloy compositions. The first experimental measurements of the spin-orbit splitting in the GaNAsBi quaternary alloy were obtained, which showed that it is approximately independent of N content, in agreement with theory. The real component of the refractive index in the transparent region below the band gap was found to decrease as the band gap increased for all of the alloys studied, following the usual relations for conventional semiconductors. This work provides key electronic and optical parameters for the development of photonic devices based on these novel alloys.
Theoretical investigation into negative differential resistance characteristics of resonant tunneling diodes based on lattice-matched and polarization-matched AlInN/GaN heterostructures
Authors: Rong Taotao , Yang Lin-An , Yang Lin , Hao Yue
Published: January 2018

In this work, we report an investigation of resonant tunneling diodes (RTDs) with lattice-matched and polarization-matched AlInN/GaN heterostructures using the numerical simulation. Compared with the lattice-matched AlInN/GaN RTDs, the RTDs based on polarization-matched AlInN/GaN hetero-structures exhibit symmetrical conduction band profiles due to eliminating the polarization charge discontinuity, which achieve the equivalence of double barrier transmission coefficients, thereby the relatively high driving current, the high symmetry of current density, and the high peak-to-valley current ratio (PVCR) under the condition of the positive and the negative sweeping voltages. Simulations show that the peak current density approaches 1.2 × 107 A/cm2 at the bias voltage of 0.72 V and the PVCR approaches 1.37 at both sweeping voltages. It also shows that under the condition of the same shallow energy level, when the trap density reaches 1 × 1019 cm−3, the polarization-matched RTDs still have acceptable negative differential resistance (NDR) characteristics, while the NDR characteristics of lattice-matched RTDs become irregular. After introducing the deeper energy level of 1 eV into the polarization-matched and lattice-matched RTDs, 60 scans are performed under the same trap density. Simulation results show that the degradation of the polarization-matched RTDs is 22%, while lattice-matched RTDs have a degradation of 55%. It can be found that the polarization-matched RTDs have a greater defect tolerance than the lattice-matched RTDs, which is beneficial to the available manufacture of actual terahertz RTD devices.
Atomistic simulation of femtosecond laser pulse interactions with a copper film: Effect of dependency of penetration depth and reflectivity on electron temperature
Authors: Amouye Foumani A. , Niknam A. R.
Published: January 2018

The response of copper films to irradiation with laser pulses of fluences in the range of 100–6000 J/m2 is simulated by using a modified combination of a two-temperature model (TTM) and molecular dynamics (MD). In this model, the dependency of the pulse penetration depth and the reflectivity of the target on electron temperature are taken into account. Also, the temperature-dependent electron-phonon coupling factor, electron thermal conductivity, and electron heat capacity are used in the simulations. Based on this model, the dependence of the integral reflectivity on pulse fluence, the changes in the film thickness, and the evolution of density and electron and lattice temperatures are obtained. Moreover, snapshots that show the melting and disintegration processes are presented. The disintegration starts at a fluence of 4200 J/m2, which corresponds with an absorbed fluence of 616 J/m2. The calculated values of integral reflectivity are in good agreement with the experimental data. The inclusion of such temperature-dependent absorption models in the TTM-MD method would facilitate the comparison of experimental data with simulation results.
AlGaN-based deep UV LEDs grown on sputtered and high temperature annealed AlN/sapphire
Authors: Susilo Norman , Hagedorn Sylvia , Jaeger Dominik , Miyake Hideto , Zeimer Ute , Reich Christoph , Neuschulz Bettina , Sulmoni Luca , Guttmann Martin , Mehnke Frank , Kuhn Christian , Wernicke Tim , Weyers Markus , Kneissl Michael
Published: January 2018

The performance characteristics of AlGaN-based deep ultraviolet light emitting diodes (UV-LEDs) grown by metalorganic vapor phase epitaxy on sputtered and high temperature annealed AlN/sapphire templates are investigated and compared with LEDs grown on epitaxially laterally overgrown (ELO) AlN/sapphire. The structural and electro-optical properties of the devices on 350 nm sputtered and high temperature annealed AlN/sapphire show similar defect densities and output power levels as LEDs grown on low defect density ELO AlN/sapphire templates. After high temperature annealing of the 350 nm sputtered AlN, the full widths at half maximum of the (0002) and (101¯2) reflections of the high resolution x-ray diffraction rocking curves decrease by one order of magnitude to 65 arc sec and 240 arc sec, respectively. The curvature of the sputtered and HTA AlN/sapphire templates after regrowth with 400 nm MOVPE AlN is with −80 km−1 much lower than the curvature of the ELO AlN/sapphire template of −160 km−1. The on-wafer measured output powers of 268 nm LEDs grown on 350 nm sputtered and high temperature annealed AlN/sapphire templates and ELO AlN/sapphire templates were 0.70 mW and 0.72 mW at 20 mA, respectively (corresponding to an external quantum efficiency of 0.75% and 0.78%). These results show that sputtered and high temperature annealed AlN/sapphire provide a viable approach for the fabrication of efficient UVC-LEDs with reduced complexity and thus reduced costs.
Accurate Hugoniots and sound velocities of bismuth under shock compression in the 38-100 GPa range
Authors: Xi Feng , Jin Ke , Geng Huayun , Li Yinghua , Tan Ye , Li Jun , Zhang Yi , Zhang Lin , Cai Lingcang , Sun Yi
Published: January 2018

Dynamic compression experiments of bismuth (Bi) in a shock pressure range of 38-100 GPa were conducted using an explosive drive. The time-resolved particle velocity profiles at the Bi/LiF (lithium fluoride) interface and the impact velocities were recorded with a displacement interferometer system for any reflector (DISAR). Shock velocities of Bi were measured based on the shorted-pin technique. Sound velocities of Bi were obtained from the peak state time duration measurements with the overtake method. Uncertainties in the measured Hugoniots and sound velocities were analyzed carefully. The new Hugoniot relation, Us = (1.666 ± 0.057) km/s + (1.596 ± 0.037)Up (1.13 km/s ≤Up≤2.05 km/s), was determined by fitting the measured shock velocity and particle velocity to a line. The relation between the Grüneisen coefficient and the density, γρ=const., is found to be a good approximation to describe the sound velocities of Bi above the shock-induced melting pressure, by carefully analysis of the sound velocity data.
Guiding of charged particle beams in curved capillary-discharge waveguides
Authors: Pompili R. , Castorina G. , Ferrario M. , Marocchino A. , Zigler A.
Published: January 2018

A new method able to transport charged particle beams along a curved path is presented. It is based on curved capillary-discharge waveguides where the induced azimuthal magnetic field is used to focus the beam and, at the same time, keep it close to the capillary axis. We show that such a solution is highly tunable, it allows to develop compact structures providing large deflecting angles and, unlike conventional solutions based on bending magnets, preserves the beam longitudinal phase space. Such a feature, in particular, is very promising when dealing with ultra-short bunches for which non-trivial manipulations on the longitudinal phase spaces are usually required when employing conventional deflecting devices.
Potassium-doped n-type bilayer graphene
Authors: Yamada Takatoshi , Okigawa Yuki , Hasegawa Masataka
Published: January 2018

Potassium-doped n-type bilayer graphene was obtained. Chemical vapor deposited bilayer and single layer graphene on copper (Cu) foils were used. After etching of Cu foils, graphene was dipped in potassium hydroxide aqueous solutions to dope potassium. Graphene on silicon oxide was characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and Raman spectroscopy. Both XPS and EDX spectra indicated potassium incorporation into the bilayer graphene via intercalation between the graphene sheets. The downward shift of the 2D peak position of bilayer graphene after the potassium hydroxide (KOH) treatment was confirmed in Raman spectra, indicating that the KOH-treated bilayer graphene was doped with electrons. Electrical properties were measured using Hall bar structures. The Dirac points of bilayer graphene were shifted from positive to negative by the KOH treatment, indicating that the KOH-treated bilayer graphene was n-type conduction. For single layer graphene after the KOH treatment, although electron doping was confirmed from Raman spectra, the peak of potassium in the X-ray photoelectron spectroscopy (XPS) spectrum was not detected. The Dirac points of single layer graphene with and without the KOH treatment showed positive.
Band offset and electron affinity of MBE-grown SnSe2
Authors: Zhang Qin , Li Mingda (Oscar) , Lochocki Edward B. , Vishwanath Suresh , Liu Xinyu , Yan Rusen , Lien Huai-Hsun , Dobrowolska Malgorzata , Furdyna Jacek , Shen Kyle M. , Cheng Guangjun , Hight Walker Angela R. , Gundlach David J. , Xing Huili G. , Nguyen N. V.
Published: January 2018

SnSe2 is currently considered a potential two-dimensional material that can form a near-broken gap heterojunction in a tunnel field-effect transistor due to its large electron affinity which is experimentally confirmed in this letter. With the results from internal photoemission and angle-resolved photoemission spectroscopy performed on Al/Al2O3/SnSe2/GaAs and SnSe2/GaAs test structures where SnSe2 is grown on GaAs by molecular beam epitaxy, we ascertain a (5.2 ± 0.1) eV electron affinity of SnSe2. The band offset from the SnSe2 Fermi level to the Al2O3 conduction band minimum is found to be (3.3 ± 0.05) eV and SnSe2 is seen to have a high level of intrinsic electron (n-type) doping with the Fermi level positioned at about 0.2 eV above its conduction band minimum. It is concluded that the electron affinity of SnSe2 is larger than that of most semiconductors and can be combined with other appropriate semiconductors to form near broken-gap heterojunctions for the tunnel field-effect transistor that can potentially achieve high on-currents.
Efficiency enhancement of ZnO/Cu2O solar cells with well oriented and micrometer grain sized Cu2O films
Authors: Zang Zhigang
Published: January 2018

Cu2O is one of the attractive photovoltaic materials for solar cells because of its low cost, nontoxicity, and good mobility. In this paper, an obvious enhancement of power conversion efficiency (PCE) for ZnO/Cu2O solar cells with perfectly oriented and micrometer grain sized Cu2O films was experimentally demonstrated. Cu2O was fabricated using radical oxidation of Cu foils at a low temperature of 500 °C. When followed by a rapid quenching and post annealing treatment, the perfectly oriented and micrometer sized Cu2O crystals (3∼4 μm) could be obtained. The crystal structure and optical properties of Cu2O were investigated in detail. Compared to conventional solar cells without any treatment, the PCE of the solar cells based on Cu2O with treatment was 3.18%, corresponding to a significant PCE improvement of 60.6%.
LaAlO3: A substrate material with unusual ferroelastic properties
Authors: Kustov S. , Liubimova Iu. , Salje E. K. H.
Published: January 2018

Twin boundary dynamics in LaAlO3 is associated with non-linear anelasticity. Ultrasonic studies of non-linear twin boundary dynamics between 80 and 520 K show that cooling substrates from temperatures near the ferroelastic transition at 813 K generate three characteristic thermal regimes with different non-linear dynamics. Twin boundaries are initially highly mobile. Anelastic strain amplitudes versus stress are power law distributed with an exponent of 2.5. No de-pinning was found down to elastic strain amplitudes of ε0 ∼ 10−7. The power law is gradually replaced between 370 K and 280 K by few large singularities (jerks) due to massive rearrangements of the domain structure for ε0 larger than ca. 5 × 10−5. At lower temperatures, the domain structure is pinned with well-defined thresholds for de-pinning. The de-pinning is not accompanied by global rearrangements of twin patterns below room temperature. Unexpectedly, the low-temperature critical de-pinning strain amplitude decreases with decreasing temperature, which may indicate an additional, so far unknown phase transition near 40 K.
Microscopic observation of lateral and vertical charge transportation in Si nanocrystals sandwiched by amorphous SiC layers
Authors: Xu Jie , Ji Yang , Lu Peng , Bai Gang , Ren Qingying , Xu Jun
Published: January 2018

Charge injection and transportation process is a fundamental problem to Si nanocrystals (Si-ncs) based electric and photonic devices. In the manuscript, a single layer of Si-ncs sandwiched by amorphous Si carbide (a-SiC) was prepared by excimer laser annealing of a-SiC/a-Si/a-SiC multilayers, and the charging effect was then characterized by Kelvin probe force microscopy (KPFM) on the microscopic scale. Opposite charges were injected into Si-ncs through the biased tip and formed a core-ring or up-down shaped distribution. The decay characteristics showed that these opposite charges would not only vertically tunnel through the bottom a-SiC layer to substrate but also laterally transport and recombine with each other driven by the attractive Coulomb force. Besides, the charge retention time was also found dependent on the injection biases, which is tentatively ascribed to the charge trapping by the Si-ncs/a-SiC interface states under high bias scanning. The analysis was further supported by conductive atomic force microscopy (CAFM) measurement, in which the current-voltage curves gradually shifted during the repetition test, probably because of bias screening by the trapped charges at these interface states.
Implementation of a double-grating interferometer for phase-contrast computed tomography in a conventional system nanotom® m
Authors: Khimchenko Anna , Schulz Georg , Thalmann Peter , Müller Bert
Published: January 2018

Visualizing the internal architecture of large soft tissue specimens within the laboratory environment in a label-free manner is challenging, as the conventional absorption-contrast tomography yields a poor contrast. In this communication, we present the integration of an X-ray double-grating interferometer (XDGI) into an advanced, commercially available micro computed tomography system nanotom® m with a transmission X-ray source and a micrometer-sized focal spot. The performance of the interferometer is demonstrated by comparing the registered three-dimensional images of a human knee joint sample in phase- and conventional absorption-contrast modes. XDGI provides enough contrast (1.094 ± 0.152) to identify the cartilage layer, which is not recognized in the conventional mode (0.287 ± 0.003). Consequently, the two modes are complementary, as the present XDGI set-up only reaches a spatial resolution of (73 ± 6) μm, whereas the true micrometer resolution in the absorption-contrast mode has been proven. By providing complimentary information, XDGI is especially a supportive quantitative method for imaging soft tissues and visualizing weak X-ray absorbing species in the direct neighborhood of stronger absorbing components at the microscopic level.
Odd conditions
Authors: Blust Robert
Published: January 2018

Since the 19th century linguists have expected to find conditioned sound changes in environments that make phonetic sense: consonants palatalize adjacent to front vowels, back vowels front if a front vowel occurs in the next syllable, stops voice between voiced segments, and so forth. Most conditioned sound changes conform to this expectation, but a surprising number do not. Some of these are well known, as the palatalization of *s before most word-initial consonants in High German. Since there is no obvious explanation for them, such changes are generally ignored in discussions of historical phonology. The result of this practice has been to give the false impression that what appear to be phonetically unmotivated sound changes are rare abnormalities that probably would conform to expectation if we had more information about them. This paper draws attention to examples of conditioning in Austronesian languages in which the phonetic properties of the context appear unrelated to those of the change, and it questions why such changes should occur. Although finding a completely satisfactory explanation has proven difficult, one general conclusion suggested by the data is that native speakers have an intuitive recognition of natural classes that is independent of phonetic motivation.
The diachrony of Spanishhaber/hacer + time
Authors: Herce Borja
Published: January 2018

Using quantitative corpus evidence from different periods, the present article analyzes the emergence and diachronic development of the Spanish time constructions (clausal and adverbial) involving contemporaryhacer‘make’ and earlierhaber‘have’. The obtained data, as well as cross-linguistic evidence, suggest that the clausal construction must have been the source of the adverbial one. A proposal is presented that could explain that development. The data show, in addition, that the grammatical properties and usage patterns of the clausal and adverbial constructions were very similar until the 16th century but have been diverging ever since. This divergence coincides with an exponential increase in the textual raw frequency of the adverbial construction, where word order fixation, erosion of the inflectional morphology and a change in the possibilities for time adjunction among others are found to occur at around the same time. This points towards a desentencialization, loss of inner structure and grammaticalization of the adverbial construction in those periods.
Fallacies of game localization
Authors: Mandiberg Stephen
Published: January 2018

Using the Twitter hashtag #TorrentialDownpour, a vocal group of disgruntled, English-speaking gamers launched an attack in early 2016 protesting the localization changes made to the game Fire Emblem Fates. While dismissible as the latest “toxic technoculture” (Massanari 2015), the #TorrentialDownpour campaign’s claims are not unfounded; there are links between localization and censorship, in that both practices adapt texts moving between markets and cultures. This article draws from translation theory and observations of localization practice to problematize #TorrentialDownpour’s claims, and in the process address some of the most prevalent fallacies involving game localization: localization is not censorship; there is no better version; and one person is not ruining gamers’ fun.
On the omission of articles and copulae in German newspaper headlines
Authors: Reich Ingo
Published: January 2018

This paper argues based on a corpus-linguistic study that both omitted articles and copulae in German headlines are to be treated as null elements NA and NC. Both items need to be licensed by a specific (parsing) strategy known as discourse orientation (Huang, 1984), which is also applicable in the special register of headlines. It is shown that distinguishing between discourse and sentence orientation and correlating these two strategies with λ-binding and existential quantification, respectively, naturally accounts for an asymmetry in article omission observed in Stowell (1991).
MARCH1 protects the lipid raft and tetraspanin web from MHCII proteotoxicity in dendritic cells
Authors: Oh Jaehak , Perry Justin S.A. , Pua Heather , Irgens-Möller Nicole , Ishido Satoshi , Hsieh Chyi-Song , Shin Jeoung-Sook
Published: January 2018

Dendritic cells (DCs) produce major histocompatibility complex II (MHCII) in large amounts to function as professional antigen presenting cells. Paradoxically, DCs also ubiquitinate and degrade MHCII in a constitutive manner. Mice deficient in the MHCII-ubiquitinating enzyme membrane-anchored RING-CH1, or the ubiquitin-acceptor lysine of MHCII, exhibit a substantial reduction in the number of regulatory T (Treg) cells, but the underlying mechanism was unclear. Here we report that ubiquitin-dependent MHCII turnover is critical to maintain homeostasis of lipid rafts and the tetraspanin web in DCs. Lack of MHCII ubiquitination results in the accumulation of excessive quantities of MHCII in the plasma membrane, and the resulting disruption to lipid rafts and the tetraspanin web leads to significant impairment in the ability of DCs to engage and activate thymocytes for Treg cell differentiation. Thus, ubiquitin-dependent MHCII turnover represents a novel quality-control mechanism by which DCs maintain homeostasis of membrane domains that support DC’s Treg cell–selecting function.
Homeomorphisms of Čech–Stone remainders: the zero-dimensional case
Authors: Farah Ilijas , McKenney Paul
Published: January 2018

We prove, using a weakening of the Proper Forcing Axiom, that any homemomorphism between Čech–Stone remainders of any two locally compact, zero-dimensional Polish spaces is induced by a homeomorphism between their cocompact subspaces.
A Randomized Clinical Trial Showing Persisting Reductions in Depressive Symptoms in HIV-Infected Rural Adults Following Brief Telephone-Administered Interpersonal Psychotherapy
Authors: Heckman Timothy G , Markowitz John C , Heckman Bernadette D , Woldu Henok , Anderson Timothy , Lovejoy Travis I , Shen Ye , Sutton Mark , Yarber William
Published: January 2018

Depressed HIV-infected rural persons who received 9 sessions of telephone-delivered interpersonal psychotherapy (IPT) reported significantly fewer depressive symptoms than non-intervention participants at long-term follow-up.
American Nuclear Literature on Hiroshima and Nagasaki
Authors: Itoh Shoko
Published: January 2018

Literature on Hiroshima and Nagasaki cannot be limited to works on the atomic bomb or fiction referring specifically to these locations. Rather, in the nuclear age, it must include a variety of literary works that are conscious of the destiny of the earth, given the danger of nuclear pollution, and engage with the terrible fantasy of the end of the world. As John W. Treat states in his influential critical work, Writing Ground Zero: Japanese Literature and the Atomic Bomb, “The concept of hibakusha now has to extend to everyone alive today in any region of the planet” (x–xi).

The range of nuclear-themed works that symbolically invoke Hiroshima or Nagasaki is enormous. Nuclear literature as a creation of survivors, or spiritual survivors, focuses on an awareness of the planetary catastrophe concerning Los Alamos, Trinity Site, the ground zeroes of Hiroshima and Nagasaki, and other global nuclear zones. The two nuclear sites in Japan (Hiroshima and Nagasaki) and in the United States (Los Alamos and Trinity Site) are historically connected. The authors and protagonists of nuclear literature have literal and affective transpacific and cross-cultural experiences that when considered together seek to overcome the tragic experience of the first nuclear bomb and bombing, including the Japanese acceptance of American nuclear fictions during the Cold War.
Landscape and Environment in British Fiction and Nonfiction Prose since 1945
Authors: Weston Daniel
Published: January 2018

The creative writing of landscape and environment is riding high on the research agendas of a number of scholarly fields. In literary studies, ecocriticism has seen attempts to map a set of characteristics that constitute an environmentally oriented text, often with the result that nonfiction writing (or, less often, poetry) is the form prioritized. By contrast, fiction has been seen as less capable of embracing landscape and environment because it is concerned first and foremost with human affairs and has taken the narrative shapes that typically accompany this emphasis. However, the postwar and contemporary period has seen extensive formal experimentation running counter to this set of assumptions. First, novelists concerned with landscape and environment have found ways to demonstrate the implication of human history in natural history. Second, nonfiction writers have recognized that they might profitably deploy literary forms and techniques usually associated with fiction in their writing of landscape and environment. The upshot has been a generic coalescence and the emergence of landscape writing as a category that straddles habitual divisions in the way that literary forms are conceived. The plasticity of the environment—for better or worse—has registered in urban and rural settings, as well as those that fall somewhere between this (perhaps outmoded) binary. The increasingly unavoidable knowledge of the consequences of human actions upon the environment form an important context for the falling away of older forms such as the nature novel and act as a spur to re-conceptualize both places and ways to write about them.
Women in the Upper Echelons: Women on Corporate Boards and in Top Management Teams
Authors: You Jihae , Terjesen Siri , Bilimoria Diana
Published: January 2018

In light of the growing number of women in the upper echelons, it is necessary to integrate and synthesize research on women at the top of corporations. The extant literature occurs in several disciplines—appearing in the fields of management, strategy, finance, economics, organizational behavior, ethics, sociology, and industrial relations—and is disparate and fragmented. A large and growing set of scholars provide various theoretical perspectives and empirical findings addressing organizational demographics, supply side factors, and outcomes. A number of theories are employed to understand the issue of women in the upper echelons, including resource dependence, tokenism and critical mass, glass cliff, social identity, human capital, social capital, and signaling theories. Most articles use U.S. data and tend to deal with the effect of female CEOs or that of female representation on corporate boards and top management teams (TMTs) on various firm-level outcomes. The majority of the studies investigate a potential relationship between gender diversity and financial performance. Research on this topic can guide policy and practice, improving the performance of organizations and the individuals who work within them.