bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimum break relay dependency set approach for coordination of directional relays in multi‐loop networks
Authors: Chen Ming , Shi Dongyuan , Duan Xianzhong
Published: January 2017

Opening all of the directional loops in the network is a key step during calculating protection setting values of directional over‐current or distance relays. The existing method based on minimum break point set leads to large amounts of broken relay dependency relations. A new method for coordination of directional relays based on minimum break relay dependency set (MBRDS) is proposed. First, a mathematical model for determining MBRDS is established, and a method based on self‐adaptive biogeography‐based optimisation (SaBBO) is proposed to effectively solve the model. Then case studies on various test systems verify the feasibility and efficiency of the proposed approach. Moreover, comparison with biogeography‐based optimisation, particle swarm optimisation, and genetic algorithm confirms that SaBBO has faster convergence speed, stronger robustness, and higher convergence precision in determining the MBRDS.
Phasor measurement unit based wide‐area monitoring and information sharing between micro‐grids
Authors: Samantaray Subhransu R. , Kamwa Innocent , Joos Geza
Published: January 2017

Micro‐grid (MG) monitoring and information sharing between them through a central monitoring unit is required in the present day operational environment. The proposed research focuses on developing wide‐area monitoring platform for multiple MGs running in parallel. This is achieved by using C37.118.1 complied phasor measurements units (PMUs) which provides accurate and reliable information monitoring at remote ends of the MGs and are further connected to the Phasor Data Concentrator which acts as the central monitoring unit. This process not only retrieves information at different nodes of the MGs equipped with PMUs, but the information can be exchanged between MGs for further action if required during contingencies. The PMUs are used to monitor phasors (amplitude and phases) and frequency of fundamentals which are further used to compute wide‐area functions at different operating nodes of the MGs at grid connected and islanded modes of operation including different operating conditions. The proposed PMU and MG models are developed on MATLAB/SIMULINK platform. Extensive test results indicate that the proposed monitoring process is highly essential to retrieve the operational status of the multiple MGs observed at the central monitoring unit.
Accuracy analysis and improvement of the state‐queuing model for the thermostatically controlled loads
Authors: Bao Yu‐Qing , Hu Minqiang , Hong Ying‐Yi , Chen Pei‐Pei , Ju Jia‐Qi , Ma Gang
Published: January 2017

The development of smart metering technologies makes it possible to apply the thermostatically controlled loads (TCLs) into the demand response programs such as direct load control. To characterise the dynamics of a large number of TCLs, the computationally efficient sate‐queuing (SQ) model is designed in some recent research works. However, very few attentions have been given to its accuracy. This study reviews the existing SQ modelling approach, and reveals its limitations in the accuracy by comprehensive comparison and analysis. To improve the accuracy of the SQ model, a modification method is specially designed based on the optimisation technique. Numerous simulation results verify the effectiveness of the proposed method.
Impact of phase‐locked loop on small‐signal dynamics of the line commutated converter‐based high‐voltage direct‐current station
Authors: Guo Chunyi , Zhao Chengyong , Iravani Reza , Ding Hui , Wang Xiaolin
Published: January 2017

This study investigates the impact of phase‐locked loop (PLL) and DC‐side voltage controller on small‐signal dynamics of the high‐voltage direct‐current (HVDC) inverter station system which utilises line commutated converter (LCC) technology. The studies are conducted based on eigenanalysis of a linearised model of a study system and verified by time‐domain simulation studies in the PSCAD platform. The studies show that under weak grid conditions, e.g. short‐circuit ratio (SCR) = 1, parameters of PLL and DC‐side voltage controller of the LCC‐HVDC station can highly impact the damping of the oscillatory modes and even cause instability. The studies also show that the voltage control parameters can be selected to prevent PLL‐induced instability. The studies also (i) show that maximum available power and critical SCR are highly affected by PLL and DC‐side voltage control and (ii) propose a procedure to systematically determine these indices.
Game‐theoretic dispatch control in microgrids considering network losses and renewable distributed energy resources integration
Authors: Mojica‐Nava Eduardo , Rivera Sergio , Quijano Nicanor
Published: January 2017

A distributed population games algorithm is proposed to solve the dispatch problem in microgrids to respond dynamically to the requirements of the system. This study extends the distributed replicator dynamics (RD) algorithm, it has four main contributions. First, the authors apply the distributed RD to a distributed generator dispatch over a communication topology in a microgrid test system. Second, they consider power losses of the networked microgrid on the distributed RD. Third, they propose an algorithm to estimate robust loss coefficients of the network considering different demand patterns through a combination of two heuristic optimisation algorithms. Finally, the uncertainties of wind power are considered as a renewable generation integration case. The simulation results show that the proposed distributed control algorithm of a microgrid is able to integrate the economic dispatch problem with frequency control considering the entire network topology.
Cylindrical near‐field assessment of wearable antennas for body‐centric communications
Authors: Paraskevopoulos Anastasios , Tsolis Aris , Vardaxoglou John C. , Alexandridis Antonis A.
Published: January 2017

In this study, a measurement methodology is proposed for characterising wearable antennas on different locations of the human body. With the conventional roll‐over‐azimuth far‐field system, it is impractical to capture the full spherical radiation pattern. A cylindrical near‐field (CNF) technique is employed here which facilitates wearable antenna measurements on a solid full‐body anthropomorphic phantom and readily produces the antenna radiation efficiency. The installed antenna efficiency is an important parameter for optimising a wearable system design and improving channel performance. The procedure of the CNF measurement is validated using a printed dipole antenna as a reference in horizontal and vertical polarisation parallel to body surface. Two textile wearable antennas with distinct radiation characteristics are designed, fabricated and assessed on the body phantom to operate at 2.4 GHz ISM band. Near‐field and transformed far‐field measurement results are presented and compared with electromagnetic simulations in order to demonstrate the benefits of the proposed measurement method.
Capacity analysis of an IEEE 802.11n system in a residential house based on estimated specular and dense multipath components
Authors: Tanghe Emmeric , Gaillot Davy P. , Plets David , Joseph Wout , Liénard Martine , De Ketelaere Wim , Martens Luc
Published: January 2017

This study analyses the multiple‐input multiple‐output (MIMO) capacity in a residential house. The capacity calculation is based on physical radio channels estimated from channel sounding measurements. Both specular and dense multipath components are estimated from the channel sounding data with the RiMAX maximum‐likelihood algorithm. In particular, the capacity analysis is made for a 2 × 2 IEEE 802.11n MIMO system that conforms to the legacy mode of the standard and operates in the 2.4 GHz ISM band. The contribution of dense multipath to the channel capacity is quantified by calculating the capacity of radio channels for which the dense multipath is ignored and only the specular multipath is retained. It is found that ignoring dense multipath underestimates the capacity on average by 1.1, 9.1, and 37.8% for line‐of‐sight, obstructed line‐of‐sight, and non‐line‐of‐sight situations, respectively.
Design of a compact dual‐polarised slot antenna with enhanced gain
Authors: Liu Hu , Liu Ying , Gong Shuxi
Published: January 2017

A compact dual‐polarised slot antenna with improved gain is presented in this study. A cross‐shaped slot antenna fed by two orthogonal microstrip feed lines is proposed to achieve dual polarisations. A symmetrical feeding structure is employed to realise high isolation between the two ports by utilising a one‐to‐two divider. The working principles of the slot antenna fed by a fork‐like microstrip are investigated in detail for the first time. In addition, a parasitic cross‐shaped slot is added to improve the impedance matching and directivity of the proposed antenna. The measured results show that the proposed antenna can cover the whole WiMAX band ranging from 3.27 to 3.68 GHz. The cross‐polarisation levels are less than −30 dB in the boresight direction and lower than −25 dB within 3‐dB beamwidth in both E‐ and H‐planes. The gain of the antenna is 9.15 dBi ± 0.25 dB and the port isolation is greater than 27 dB across the operating band.
Small antenna design for very compact devices and wearables
Authors: Gonçalves Ricardo , Carvalho Nuno B. , Pinho Pedro
Published: January 2017

In this study the authors present a possible solution for a compact printed folded dipole antenna, designed to match an nRF51822 Bluetooth Smart device. The use of a differential design avoids the need for a balun and the matching network between the IC and the antenna, therefore, reducing the power loss in these components. The performance of the proposed printed dipole is compared with the standard application of a quarter‐wave monopole antenna as proposed by the manufacturer and a commercial ceramic antenna. It is shown that the proposed design presents better radiation properties than the other two approaches, which resulted in an increased communication range of the system by 50%. Measurements are compared with simulation to attest the validity of the authors’ proposal.
Zinc oxide–tungsten‐based pyramids in construction of ultra‐broadband metamaterial absorber for solar energy harvesting
Authors: Ünal Emin , Bağmancı Mehmet , Karaaslan Muharrem , Akgol Oguzhan , Arat Hüseyin Turan , Sabah Cumali
Published: January 2017

A new broadband absorber is investigated for the entire frequency domain of solar light (infrared, visible light and ultraviolet). While current absorbers in the literature have limited operation frequencies, investigated structure has a wide bandwidth and a perfect absorptivity (99% at nearly all operation frequencies). The proposed metamaterial absorber has ultra‐broadband, angle‐insensitive, polarisation‐independent characteristics with a different conventional pyramid shape. Whereas other pyramid or truncate pyramid‐shaped multi‐layered metamaterial absorber (MA) are composed of multi‐layered dielectrics and metal combinations, the proposed structure has only three layers. As a result of exhibiting perfect absorption characteristic, the proposed structure is a new candidate for energy harvesting applications in solar energy collection.
The ALMA Redshift 4 Survey (AR4S)
Authors: Schreiber C. , Pannella M. , Leiton R. , Elbaz D. , Wang T. , Okumura K. , Labbé I.
Published: January 2017

We introduce the ALMA Redshift 4 Survey (AR4S), a systematic ALMA survey of all the known galaxies with stellar mass (M∗) larger than 5 × 1010M⊙ at 3.5 <z< 4.7 in the GOODS–south, UDS and COSMOS CANDELS fields. The sample we have analyzed in this paper is composed of 96 galaxies observed with ALMA at 890 μm (180 μm rest-frame) with an on-source integration time of 1.3 min per galaxy. We detected 32% of the sample at more than 3σ significance. Using the stacked ALMA and Herschel photometry, we derived an average dust temperature of 40 ± 2 K for the whole sample, and extrapolate the LIR and SFR for all our galaxies based on their ALMA flux. We then used a forward modeling approach to estimate their intrinsic sSFR distribution, deconvolved of measurement errors and selection effects: we find a linear relation between SFR and M∗, with a median sSFR = 2.8 ± 0.8 Gyr and a dispersion around that relation of 0.28 ± 0.13 dex. This latter value is consistent with that measured at lower redshifts, which is proof that the main sequence of star-forming galaxies was already in place at z = 4, at least among massive galaxies. These new constraints on the properties of the main sequence are in good agreement with the latest predictions from numerical simulations, and suggest that the bulk of star formation in galaxies is driven by the same mechanism from z = 4 to the present day, that is, over at least 90% of the cosmic history. We also discuss the consequences of our results on the population of early quiescent galaxies. This paper is part of a series that will employ these new ALMA observations to explore the star formation and dust properties of the massive end of the z = 4 galaxy population.
HMGB1 in the Pathogenesis of Nasal Inflammatory Diseases and its Inhibition as New Therapeutic Approach: A Review from the Literature
Authors: Bellussi Luisa , Cocca Serena , Passali Giulio , Passali Desideri
Published: January 2017

Introduction This study is a systematic review on recent developments about the importance of HMGB1 protein in the pathogenesis of rhino-sinusal inflammatory diseases. We also report data on the use of 18-β-glycyrrhetic acid (GA), which has been shown able to inhibit the pro-inflammatory activities of HMGB1, in young patients affected by allergic rhinitis and complaining of nasal obstruction as main symptom.

Objectives The objective of this study was to review the literature to demonstrate the importance of HMGB1 in the pathogenesis of nasal inflammatory disorders and understand whether the inhibition of this protein may be an efficacious and innovative therapeutic strategy for patients with rhino-sinusal inflammation.

Data Synthesis Authors searched for pertinent articles indexed in PubMed, Scopus, and other health journals between 2004 and 2015.

In total, the authors gathered 258 articles: 219 articles through Pubmed and 39 articles from other search engines. The search terms used were as follows: HMGB1 AND “respiratory epithelium,” “airway inflammation,” “rhinitis,” “allergic rhinitis,” “rhinosinusitis,” “nasal polyposis,” “glycyrrhetic acid,” “children.”

Conclusions Patients with severe symptoms have the highest serum levels and the highest extracellular expression of HMGB1. GA inhibits HMGB1 chemotactic and mitogenic function by a scavenger mechanism on extracellular HMGB1 accumulation stimulated by lipopolysaccharides in vitro. Treatment of allergic rhinitis with GA is not associated with local or systemic side effects in children and adults.
Modeling linear Rayleigh wave sound fields generated by angle beam wedge transducers
Authors: Zhang Shuzeng , Li Xiongbing , Jeong Hyunjo , Hu Hongwei
Published: January 2017

In this study, the reciprocity theorem for elastodynamics is transformed into integral representations, and the fundamental solutions of wave motion equations are obtained using Green’s function method that yields the integral expressions of sound beams of both bulk and Rayleigh waves. In addition to this, a novel surface integral expression for propagating Rayleigh waves generated by angle beam wedge transducers along the surface is developed. Simulation results show that the magnitudes of Rayleigh wave displacements predicted by this model are not dependent on the frequencies and sizes of transducers. Moreover, they are more numerically stable than those obtained by the 3-D Rayleigh wave model. This model is also applicable to calculation of Rayleigh wave beams under the wedge when sound sources are assumed to radiate waves in the forward direction. Because the proposed model takes into account the actual calculated sound sources under the wedge, it can be applied to Rayleigh wave transducers with different wedge geometries. This work provides an effective and general tool to calculate linear Rayleigh sound fields generated by angle beam wedge transducers.
Impact of Fe site Co substitution on superconductivity of Fe1-xCoxSe0.5Te0.5 (x = 0.0 to 0.10): A flux free single crystal study
Authors: Maheshwari P. K. , Gahtori Bhasker , Gupta Anurag , Awana V. P. S.
Published: January 2017

We report synthesis of Co substitution at Fe site in Fe1-xCoxSe0.5Te0.5 (x=0.0 to 0.10) single crystals via vacuum shield solid state reaction route using flux free method. Single crystal XRD results showed that these crystals grow in (00l) plane i.e., orientation in c-direction. All the crystals possess tetragonal structure having P4/nmm space group. Detailed scanning electron microscopy (SEM) images show that the crystals are grown in slab-like morphology. The EDAX results revealed the final elemental composition to be near stoichiometric. Powder X-Ray diffraction (PXRD) Rietveld analysis results show that (00l) peaks are shifted towards higher angle with increasing Co concentration. Both a and c lattice parameters decrease with increasing Co concentration in Fe1-xCoxSe0.5Te0.5 (x=0.0 to 0.10) single crystals. Low temperature transport and magnetic measurements show that the superconducting transition temperature (Tc), decreases from around 12K to 10K and 4K for x=0.03 and x=0.05 respectively. For x=0.10 crystal superconductivity is not observed down to 2K. Electrical resistivity measurement of Fe0.97Co0.03Se0.5Te0.5 single crystal under magnetic field up to 14Tesla for H//ab and H//c clearly showed the anisotropy nature of superconductivity in these crystals. The upper critical field Hc2(0), being calculated using conventional one band Werthamer–Helfand–Hohenberg (WHH) equation, for x=0.03 crystal comes around 70Tesla, 45Tesla and 35Tesla for normal state resistivity criterion ρn=90%, 50% and 10% criterion respectively for H//c and around 100Tesla, 75Tesla and 60Tesla respectively for H//ab. The activation energy of Fe0.97Co0.03Se0.5Te0.5 single crystal is calculated with the help of TAFF model for both H//c and H//ab direction. In conclusion, Co substitution at Fe site in Fe1-xCoxSe0.5Te0.5 suppresses superconductivity.
High-resolution quasi-monochromatic X-ray imaging using a Fresnel phase zone plate and a multilayer mirror
Authors: Do A. , Troussel Ph. , Baton S. D. , Dervieux V. , Gontier D. , Lecherbourg L. , Loupias B. , Obst L. , Pérez F. , Renaudin P. , Reverdin Ch. , Rubbelynck C. , Stemmler Ph. , Soullié G.
Published: January 2017

High-resolution, high-sensitivity X-ray imaging is a real challenge in laser plasma diagnostic to attain reliable data in high-energy density plasma experiments. In this context, ultra-high-intensity lasers generate hot and dense plasma but only in a small volume. An experiment has been performed at the LULI2000 laser facility to diagnose such plasma conditions from thermal spectroscopic data. To image the emission zone plasma’s Al Heβ, a Fresnel-lens-based X-ray imager has been developed. It features a 846 μm-diameter Fresnel Phase Zone Plate (FPZP) and a Pd/B4C multilayer mirror (thickness d = 5.1 nm). This association can be used between 1500 eV and 2100 eV. The FPZP’s efficiency was measured on a synchrotron facility (SOLEIL) and its spatial resolution in a laser facility (EQUINOX). The mirror reflectivity was measured on the synchrotron facility BESSY II. With experimental conditions, the system resolution reaches 3.8 ± 0.6 μm with an adequate efficiency in the 1800 eV–1900 eV energy range with a solid angle of 9 × 10−6 sr. Consequently, a FPZP is an excellent optics setup for high-resolution quasi-monochromatic X-ray imaging and provides a good collection angle. Bragg-Fresnel lenses, based on the principle of FPZP and mirrors, are currently designed for an X-ray imager at the Laser MégaJoule facility.
Microwave modulation characteristics of twisted liquid crystals with chiral dopant
Authors: Yuan Rui , Xing Hongyu , Ye Wenjiang
Published: January 2017

Adding a chiral dopant in twisted nematic (TN) liquid crystal cell can stabilize the orientation of liquid crystal molecules, particularly in high TN (HTN) or super TN (STN) liquid crystal cells. The difference in pitches in liquid crystal is induced by the chiral dopant, and these different pitches affect the orientation of liquid crystal director under an external applied voltage and influence the characteristics of microwave modulation. To illustrate this point, the microwave phase shift per unit length (MPSL) versus voltage is calculated on the basis of the elastic theory of liquid crystal and the finite-difference iterative method. Enhancing the pitch induced by the chiral dopant in liquid crystal increases the MPSLs, but the stability of the twisted structures is decreased. Thus, appropriate pitches of 100d, 4d, and 2d can be applied in TN, HTN, and STN cells with cell gap d to enhance the characteristics of microwave modulation and stabilize the structures in twisted cell. This method can improve the characteristics of liquid crystal microwave modulators such that the operating voltage and the size of such phase shifters can be decreased.
Thermal conductivity of liquid/carbon nanotube core-shell nanocomposites
Authors: Yamada Yutaka , Askounis Alexandros , Ikuta Tatsuya , Takahashi Koji , Takata Yasuyuki , Sefiane Khellil
Published: January 2017

Hollow carbon nanotubes (CNTs) were impregnated with an ionic liquid, resulting in a composite core-shell nanostructure. Liquid infusion was verified by transmission electron microscopy and rigorous observations unveiled that the nanocomposite is stable, i.e., liquid did not evaporate owing to its low vapor pressure. A series of individual nanostructures were attached on T-type heat sensors and their thermal behavior was evaluated. The liquid core was found to reduce the thermal conductivity of the base structure, CNT, from ca. 28 W/mK to ca. 15 W/mK. These findings could contribute to a better understanding of nanoscale thermal science and potentially to applications such as nanodevice thermal management and thermoelectric devices.
Investigation of the light-extraction efficiency in 280 nm AlGaN-based light-emitting diodes having a highly transparent p-AlGaN layer
Authors: Yun Joosun , Hirayama Hideki
Published: January 2017

The light-extraction efficiency (LEE) of 280 nm AlGaN-based ultraviolet light-emitting diodes (UV-LEDs) with a highly transparent p-AlGaN layer was investigated using a three-dimensional (3D) finite-difference time-domain method. This investigation clearly demonstrated that two major problems need to be solved to obtain an LED structure that guarantees the high LEE for both TE and TM polarized light emissions. The first problem was shown to be light confined in quantum wells (QW) and the n-AlGaN layer. By analyzing a conventional LED structure with a highly transparent p-AlGaN layer and an AlN/sapphire template, the major cause of the light confinement was confirmed as the total internal reflection (TIR) at the interfaces between the EBL, QW, n-AlGaN, and AlN layers. Especially, light confined in the QWs is severe due to TIR at the interfaces adjacent to them. This light diminishes with time due to absorption. By removing the AlN/sapphire layer beneath the n-AlGaN layer, adopting an Al electrode, introducing cone-shaped pillars on the n-AlGaN layer and having cylindrical holes through the Al electrode, LEEs of 54.3% and 49.3% were attained for the TE and TM polarized emissions, respectively. This result demonstrates that just by offering proper light escape angles directly to the light confining layers, attainment of LEEs of more than 50% is possible. The second problem is severe light absorption by the metal electrode. LEE vs. the reflectivity of the metal electrode was analyzed for several LED structures. In the extracted results, an exponential increase in LEE as the metal reflectivity increases was shown, which means reflection at the interface between the p-AlGaN layer and the metal electrode is repeated several times until the light escapes from the LED. Also, it was shown that once the reflectivity of the metal electrode is more than 90%, any additional small increase in reflectivity increases LEE significantly. These results emphasize that without high reflectivity of the metal electrode and without releasing the light confined in several of the epitaxial layers, attaining LEEs of over 70% is difficult for AlGaN-based LEDs operating at 280 nm.
High positive magnetoresistance in Ge films at low temperatures
Authors: Mitin V. F. , Kholevchuk V. V. , Soloviev E. A.
Published: January 2017

High positive magnetoresistance is found and investigated in p-Ge films on GaAs at low temperatures (1.4–4.2 K) and in magnetic fields up to 14 T. The film resistance grows exponentially with magnetic field. At a temperature of 1.4 K and in a magnetic field of 14 T, the film resistance is increased by a factor of 3.8. The magnetoresistance also grows exponentially as temperature is reduced. The Mott variable-range hopping conduction is observed in the films studied in the 1.4–21 K temperature range. It is shown that experimentally observed magnetoresistance agrees well with the theory of compression of wave functions of the localized states in the plane normal to magnetic field. This results in reduction of their overlapping, decrease of electron tunneling probability, and consequently, considerable growth of film resistance. Based on experimental resistance dependences on temperature and magnetic field, the parameters of hopping resistivity in Ge films on GaAs are determined. A possibility of transition to interference effects in conduction leading to localization of charge carriers and negative magnetoresistance at temperature decrease is also discussed.
Three-point bending setup for piezoresistive gauge factor measurement of thin-film samples at high temperatures
Authors: Madsen Nis Dam , Kjelstrup-Hansen Jakob
Published: January 2017

We present a new method for measuring the piezoresistive gauge factor of a thin-film resistor based on three-point bending. A ceramic fixture has been designed and manufactured to fit a state-of-the-art mechanical testing apparatus (TA Instruments Q800). The method has been developed to test thin-film samples deposited on silicon substrates with an insulating layer of SiO2. The electrical connections to the resistor are achieved through contacts in the support points. This insures that the influence of the electrical contacts is reduced to a minimum and eliminates wire-bonding or connectors attached to the sample. During measurement, both force and deflection of the sample are recorded simultaneously with the electrical data. The data analysis extracts a precise measurement of the sample thickness (<1% error) in addition to the gauge factor and the temperature coefficient of resistivity. The sample thickness is a critical parameter for an accurate calculation of the strain in the thin-film resistor. This method provides a faster sample evaluation by eliminating an additional sample thickness measurement or alternatively an option for cross checking data. Furthermore, the method implements a full compensation of thermoelectrical effects, which could otherwise lead to significant errors at high temperature. We also discuss the magnitude of the error sources in the setup. The performance of the setup is demonstrated using a titanium nitride thin-film, which is tested up to 400 °C revealing the gauge factor behavior in this temperature span and the temperature coefficient of resistivity.
Accelerating two-dimensional nuclear magnetic resonance correlation spectroscopy via selective coherence transfer
Authors: Ye Qimiao , Chen Lin , Qiu Wenqi , Lin Liangjie , Sun Huijun , Cai Shuhui , Wei Zhiliang , Chen Zhong
Published: January 2017

Nuclear magnetic resonance (NMR) spectroscopy serves as an important tool for both qualitative and quantitative analyses of various systems in chemistry, biology, and medicine. However, applications of one-dimensional 1H NMR are often restrained by the presence of severe overlap among different resonances. The advent of two-dimensional (2D) 1H NMR constitutes a promising alternative by extending the crowded resonances into a plane and thereby alleviating the spectral congestions. However, the enhanced ability in discriminating resonances is achieved at the cost of extended experimental duration due to necessity of various scans with progressive delays to construct the indirect dimension. Therefore, in this study, we propose a selective coherence transfer (SECOT) method to accelerate acquisitions of 2D correlation spectroscopy by converting chemical shifts into spatial positions within the effective sample length and then performing an echo planar spectroscopic imaging module to record the spatial and spectral information, which generates 2D correlation spectrum after 2D Fourier transformation. The feasibility and effectiveness of SECOT have been verified by a set of experiments under both homogeneous and inhomogeneous magnetic fields. Moreover, evaluations of SECOT for quantitative analyses are carried out on samples with a series of different concentrations. Based on these experimental results, the SECOT may open important perspectives for fast, accurate, and stable investigations of various chemical systems both qualitatively and quantitatively.
Experimental and theoretical study of an atmospheric air plasma-jet
Authors: Xaubet M. , Giuliani L. , Grondona D. , Minotti F.
Published: January 2017

In this work, we present an experimental and theoretical study of a low frequency, atmospheric plasma-jet discharge in air. Voltage-current characteristics and spectroscopic data were experimentally obtained, and a theoretical model developed to gain information of different aspects of the discharge. The discharge is modeled as a cathode layer with different mechanisms of electron emission and a main discharge channel that includes the most important kinetic reactions and species. From the electric measurements, it is determined that high electric field magnitudes are attained in the main channel, depending on the gas flow rate. Using the voltage-current characteristics as an input, the model allows to determine the plasma state in the discharge, including electron, gas, and molecular nitrogen vibrational temperatures. The model also allows to infer the mechanisms of secondary electron emission that sustain the discharge.
Sigmoidal current collector for lithium-ion battery
Authors: Wang Meng , Le Anh V. , Shi Yang , Noelle Daniel J. , Wu Dengguo , Fan Jiang , Lu Weiyi , Qiao Yu
Published: January 2017

In the current study, we investigated sigmoidal current collector in lithium-ion battery (LIB). Traditionally, the active material in an LIB electrode is coated on a flat current collector. By rendering the current collector sigmoidal-shaped, cracking and debonding of active material layer could be promoted, which would considerably increase the internal impedance, as the LIB is mechanically abused, beneficial to thermal-runaway mitigation. The energy absorption capacity is also improved, enabling multifunctional LIB cell design. This technique has important relevance to large-sized LIB systems, for which cell robustness and fire safety are prioritized.
Enhancement of 𝜷-phase in PVDF films embedded with ferromagnetic Gd5Si4 nanoparticles for piezoelectric energy harvesting
Authors: Harstad Shane , D’Souza Noel , Soin Navneet , El-Gendy Ahmed A. , Gupta Shalabh , Pecharsky Vitalij K. , Shah Tahir , Siores Elias , Hadimani Ravi L.
Published: January 2017

Self-polarized Gd5Si4-polyvinylidene fluoride (PVDF) nanocomposite films have been synthesized via a facile phase-inversion technique. For the 5 wt% Gd5Si4-PVDF films, the enhancement of the piezoelectric β-phase and crystallinity are confirmed using Fourier transform infrared (FTIR) spectroscopy (phase fraction, Fβ, of 81% as compared to 49% for pristine PVDF) and differential scanning calorimetry (crystallinity, ΔXc, of 58% as compared to 46% for pristine PVDF), respectively. The Gd5Si4 magnetic nanoparticles, prepared using high-energy ball milling were characterized using Dynamic Light Scattering and Vibrating Sample Magnetometry (VSM) to reveal a particle size of ∼470 nm with a high magnetization of 11 emu/g. The VSM analysis of free-standing Gd5Si4-PVDF films revealed that while the pristine PVDF membrane shows weak diamagnetic behavior, the Gd5Si4-PVDF films loaded at 2.5 wt% and 5 wt% Gd5Si4 show enhanced ferromagnetic behavior with paramagnetic contribution from Gd5Si3 phase. The interfacial interactions between Gd5Si4 and PVDF results in the preferential crystallization of the β-phase as confirmed via the shift in the CH2 asymmetric and symmetric stretching vibrations in the FTIR. These results confirm the magnetic Gd5Si4 nanoparticles embedded in the PVDF membrane lead to an increased β-phase fraction, which paves the way for future efficient energy harvesting applications using a combination of magnetic and piezoelectric effects.
Investigation of tunable terahertz metamaterial perfect absorber with anisotropic dielectric liquid crystal
Authors: Hokmabadi Mohammad P. , Tareki Abubaker , Rivera Elmer , Kung Patrick , Lindquist Robert G. , Kim Seongsin M.
Published: January 2017

In this letter, we report the unique design, simulation and experimental verification of an electrically tunable THz metamaterial perfect absorber consisting of complementary split ring resonator (CSRR) arrays integrated with liquid crystal as the subwavelength spacer in between. We observe a shift in resonance frequency of about 5.0 GHz at 0.567 THz with a 5 V bias voltage at 1KHz between the CSRR and the metal backplane, while the absorbance and full width at half maximum bandwidth are maintained at 90% and 0.025 THz, respectively. Simulated absorption spectrum by using a uniaxial model of LC matches perfectly the experiment data and demonstrates that the effective refractive index of LC changes between 1.5 and 1.7 by sweeping a 1 kHz bias voltage from 0 V to 5 V. By matching simulation and experiment for different bias voltages, we also estimate the angle of LC molecules versus the bias voltage. Additionally, we study the created THz fields inside the spacer to gain a better insight of the characteristics of tunable response of this device. This structure and associated study can support the design of liquid crystal based tunable terahertz detectors and sensors for various applications.
Magnetic particles detection by using spin valve sensors and magnetic traps
Authors: Jitariu Andrei , Ghemes Crina , Lupu Nicoleta , Chiriac Horia
Published: January 2017

In this paper, a spin-valve sensor with integrated current lines for concentration and detection of magnetic particles is presented. This device has the advantage of not requiring an external magnetic field source such as permanent magnet to magnetize the particles or to bias the spin-valve sensor. Due to the device design, the magnetic field created by the current lines allows the control of the sensor operating point, to magnetize the particles and also to concentrate the particles in the sensor active area in order to be detected by the spin valve sensor. Detection experiments using FeCrNbB magnetic particles show that the device is capable to detect and quantify the particles in a linear scale over a concentration range of 0.1 to 1 mg/ml.
The first-principles investigations on magnetic ground-state in Sm-doped phenanthrene
Authors: Han Jia-Xing , Zhong Guo-Hua , Wang Xiao-Hui , Chen Xiao-Jia , Lin Hai-Qing
Published: January 2017

Based on the density functional theory plus the effective Coulomb repulsion U, we have investigated the crystal structure, electronic properties and magnetic characteristics in Sm-doped phenanthrene, recently characterized as a superconductor with Tc∼5−6 Kelvin. Calculated total energies of different magnetic states indicate that Sm-doped phenanthrene is stable at the ferromagnetic ground-state. Considered the strong electronic correlations effect due to the intercalation of Sm-4f electrons, we found that the Sm-4f contributes to the Fermi surface together with C-2p, which is different from K-doped phenanthrene. Compared with alkali-metal-doped phenanthrene, Sm atom has larger local magnetic moment, which suppresses the superconductivity in conventional superconductors. Our results indicate that the electron-electron correlations play an important role in superconductivity of Sm-doped phenanthrene.
Micromagnetic analysis of geometrically controlled current-driven magnetization switching
Authors: Alejos O. , Raposo V. , Hernandez M. A. , Sanchez-Tejerina L. , Moretti S. , Martinez E.
Published: January 2017

The magnetization dynamics induced by current pulses in a pair of two “S-shaped” ferromagnetic elements, each one consisting on two oppositely tilted tapered spikes at the ends of a straight section, is theoretically studied by means of micromagnetic simulations. Our results indicate that the magnetization reversal is triggered by thermal activation, which assists the current-induced domain nucleation and the propagation of domain walls. The detailed analysis of the magnetization dynamics reveals that the magnetization switching is only achieved when a single domain wall is nucleated in the correct corner of the element. In agreement with recent experimental studies, the switching is purely dictated by the shape, being independent of the current polarity. The statistical study points out that successful switching is only achieved within a narrow range of the current pulse amplitudes.
Low-field switchable dynamic anisotropy in FeCoN thin film with weak stripe domain
Authors: Wu Y. P. , Yang Yong , Yang Z. H. , Zong Baoyu , Ding Jun
Published: January 2017

In this work, the static and dynamic magnetic properties of FeCoN films with various thickness have been studied. By controlling the deposition conditions, two-fold static anisotropies, namely a perpendicular anisotropy and an in-plane anisotropy, are introduced into the films, forming weak stripe domain. It is found that, for the films with the thickness between 130 nm and 240 nm, the anisotropy of FMR response is switchable. More importantly, the switching field of the dynamic anisotropy is only about 40-50 Oe, which is far below the value required to switch traditional rotatable anisotropy. Combined with high magnetic permeability and low-field switchable anisotropy, these films are promising for practical applications in the microwave devices.
In vivo mapping of current density distribution in brain tissues during deep brain stimulation (DBS)
Authors: Sajib Saurav Z. K. , Oh Tong In , Kim Hyung Joong , Kwon Oh In , Woo Eung Je
Published: January 2017

New methods for in vivo mapping of brain responses during deep brain stimulation (DBS) are indispensable to secure clinical applications. Assessment of current density distribution, induced by internally injected currents, may provide an alternative method for understanding the therapeutic effects of electrical stimulation. The current flow and pathway are affected by internal conductivity, and can be imaged using magnetic resonance-based conductivity imaging methods. Magnetic resonance electrical impedance tomography (MREIT) is an imaging method that can enable highly resolved mapping of electromagnetic tissue properties such as current density and conductivity of living tissues. In the current study, we experimentally imaged current density distribution of in vivo canine brains by applying MREIT to electrical stimulation. The current density maps of three canine brains were calculated from the measured magnetic flux density data. The absolute current density values of brain tissues, including gray matter, white matter, and cerebrospinal fluid were compared to assess the active regions during DBS. The resulting current density in different tissue types may provide useful information about current pathways and volume activation for adjusting surgical planning and understanding the therapeutic effects of DBS.
Classical precursor to turbulence observed in a superfluid
Authors: Wilson R. Mark
Published: January 2017

An obstacle dragged through a Bose–Einstein condensate can leave a well-known pattern of vortices in its wake.
Erratic helium prices create research havoc
Authors: Kramer David
Published: January 2017

Researchers report forgoing salaries and taking on fewer graduate students to cope with volatile prices for liquid helium.
The unfolding and control of network cascades
Authors: Motter Adilson E. , Yang Yang
Published: January 2017

The same connections that give a network its functionality can promote the spread of failures and innovations that would otherwise remain confined.
The image of scientists in The Big Bang Theory
Authors: Weitekamp Margaret A.
Published: January 2017

In some ways, the hit TV show reinforces popular stereotypes about scientists. In others, notably in its affectionate portrayals, it plays against type.
Active defence by an Australian native host, Lomandra longifolia, provides resistance against Phytophthora cinnamomi
Authors: Islam Md Tohidul , Rookes James E. , Cahill David M.
Published: January 2017

Resistance is rare against the oomycete plant pathogen Phytophthora cinnamomi Rands. Only a limited number of species have been recorded as field-resistant species in Australia. However, understanding the nature of resistance of those species when grown under controlled conditions is challenging because of their slow growth and the inherent difficulties of working with a root pathogen. We assessed the Australian native species, Lomandra longifolia Labill., as a resistant species by analysing in detail the response of roots to infection by P. cinnamomi in a series of comparative tests with Lupinus angustifolius L., a highly susceptible species. Following inoculation of L. longifolia roots, lesion length and colonisation percentage were significantly less than in roots of the susceptible species. Moreover, there was no statistical difference in root growth rate, whole-plant FW and leaf relative chlorophyll content between controls and inoculated L. longifolia. We then examined three key cellular responses that are related to resistance: the production of the reactive oxygen species, H2O2, callose formation and lignin deposition in L. longifolia roots following inoculation with P. cinnamomi. The upregulation of these resistance-related components in the early hours after inoculation suggested their involvement in resistance and that this is controlled by the coordinated response of multiple components. Resistance assessment and a detailed investigation of cellular resistance components along with gene expression analysis provides a platform for further understanding of the mechanisms of resistance against this generalist pathogen and presents opportunities for manipulating susceptible species for disease resistance.
Impact of short-chain galactooligosaccharides on the gut microbiome of lactose-intolerant individuals
Authors: Azcarate-Peril M. Andrea , Ritter Andrew J. , Savaiano Dennis , Monteagudo-Mera Andrea , Anderson Carlton , Magness Scott T. , Klaenhammer Todd R.
Published: January 2017

Significance

Approximately 75% of the global human population are lactose malabsorbers. In a previous clinical trial, it was shown that feeding a high-purity galactooligosaccharide (>95% GOS) could improve symptoms of lactose-intolerant subjects, attaining lactose tolerance in a majority of subjects. To investigate the mechanism, we examined the microbiome of human subjects before and after GOS feeding. The results show a significant shift in the microbiome of responsive individuals, including lactose-fermenting microbes in their stools. The high-purity prebiotic GOS resulted in adaptive shifts in the microbiome and correlated with improvement in clinical symptoms.
Aquaporin-3 mediates hydrogen peroxide-dependent responses to environmental stress in colonic epithelia
Authors: Thiagarajah Jay R. , Chang Jeffrey , Goettel Jeremy A. , Verkman Alan S. , Lencer Wayne I.
Published: January 2017

Significance

The extracellular production of hydrogen peroxide (H
2
O
2
) by membrane or secreted oxidases has been linked to epithelial wound repair, defense against infection, and inflammation. Here, we elucidate the pathway that explains how extracellular H
2
O
2
transduces a signal into the cell to induce these critical cell functions. Our study shows the central component of this pathway in the mammalian colon is the H
2
O
2
-conducting aquaglyceroporin AQP3 and implicates this channel in innate immune responses at mucosal surfaces.
Gpr132 sensing of lactate mediates tumor–macrophage interplay to promote breast cancer metastasis
Authors: Chen Peiwen , Zuo Hao , Xiong Hu , Kolar Matthew J. , Chu Qian , Saghatelian Alan , Siegwart Daniel J. , Wan Yihong
Published: January 2017

Significance

Metastasis is a major cause of cancer mortality. However, the regulation of this complex process remains poorly understood. Due to low oxygen supply and enhanced sugar metabolism, cancer cells releases lactate to create an acidic environment. We show that a membrane receptor on macrophages called G protein-coupled receptor 132 (Gpr132) can sense and respond to this lactate signal from cancer cells. As a result, macrophages alter their functions, which, in turn, stimulates cancer metastasis to distant organs. Consequently, loss of Gpr132 in mice inhibits breast cancer metastasis; lower Gpr132 expression in patients with breast cancer correlates with better metastasis-free survival. These findings uncover knowledge and potentially novel treatment for cancer metastasis.
Mobile zinc increases rapidly in the retina after optic nerve injury and regulates ganglion cell survival and optic nerve regeneration
Authors: Li Yiqing , Andereggen Lukas , Yuki Kenya , Omura Kumiko , Yin Yuqin , Gilbert Hui-Ya , Erdogan Burcu , Asdourian Maria S. , Shrock Christine , de Lima Silmara , Apfel Ulf-Peter , Zhuo Yehong , Hershfinkel Michal , Lippard Stephen J. , Rosenberg Paul A. , Benowitz Larry
Published: January 2017

Significance

The inability of CNS pathways to regenerate after injury can lead to devastating, life-long losses in sensory, motor, and other functions. We report that after injury to the optic nerve, a widely studied CNS pathway that normally cannot regenerate, mobile zinc (Zn
2+
) increases rapidly in the processes of retinal interneurons (amacrine cells) and then transfers via vesicular release to retinal ganglion cells (RGCs), the injured projection neurons. Eliminating Zn
2+
leads to both persistent RGC survival and substantial axon regeneration with a broad therapeutic window. These findings show that signaling between interneurons and RGCs contributes to regulating the fate of RGCs after optic nerve injury, and that Zn
2+
chelation may provide a potent therapeutic approach.
How Best to Engage Users of Forensic Services in Research: Literature Review and Recommendations
Authors: Völlm Birgit , Foster Sheena , Bates Peter , Huband Nick
Published: January 2017

This rapid review summarises the currently available information on how best to engage users of forensic mental health services in the research process. A search of six electronic databases and a general Internet search identified eleven peer-reviewed journal papers and twelve reports, the majority containing information derived using qualitative methods. Five areas of particular relevance to forensic settings were identified: power relations & vulnerability issues (including ethical treatment; informed consent; attitudes of staff and other service users); practical difficulties; confidentiality and transparency; language and communication and training issues. Recommendations on engaging service users in forensic mental health research are presented.