bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultra high performance N-doped carbon catalysts for the ORR derived from the reaction between organic-nitrate anions inside a layered nanoreactor
Authors: Yeganeh Ghotbi Mohammad , Feli Behzad , Azadfalah Marziyeh , Javaheri Masoumeh
Published: October 2015

A layered organic–inorganic nanohybrid was used to produce porous N-doped carbon nanosheets as highly efficient active material in a PEFC cathode.
Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy
Authors: Hemmann Felix , Agirrezabal-Telleria Iker , Jaeger Christian , Kemnitz Erhard
Published: October 2015

A new method is described for the calculation of molar extinction coefficients for quantitative FTIR measurements of acidic surface sites.
A facile hydrothermal synthesis of MnO2 nanorod–reduced graphene oxide nanocomposites possessing excellent microwave absorption properties
Authors: Wang Yan , Guan Hongtao , Du Shangfeng , Wang Yude
Published: October 2015

MnO2 nanorod/reduced graphene oxide nanocomposites synthesized by a simple one-step hydrothermal method significantly improved the electromagnetic wave absorption performance and widened the effective absorption bandwidth.
N-3-Oxo-octanoyl-homoserine lactone as a promotor to improve the microbial flocculant production by an exopolysaccharide bioflocculant-producing bacterium Agrobacterium tumefaciens F2
Authors: Wu Dan , Li Ang , Yang Jixian , Ma Fang , Chen Han , Pi Shanshan , Wei Wei
Published: October 2015

This study showed thatAgrobacterium tumefaciensF2 can produceN-3-oxo-octanoyl-homoserine lactone (3-oxo-C8HSL), one of theN-acyl-homoserine lactone (AHL) class of microbial quorum-sensing signaling molecules.
Centrifugo-thermopneumatic fluid control for valving and aliquoting applied to multiplex real-time PCR on off-the-shelf centrifugal thermocycler
Authors: Keller M. , Wadle S. , Paust N. , Dreesen L. , Nuese C. , Strohmeier O. , Zengerle R. , von Stetten F.
Published: October 2015

Microfluidic App for automation of geometrically multiplexed real-time PCR on off-the-shelf PCR thermocycler.
Study of mean diameter and drop size distribution of emulsion drops in a modified rotating disc contactor for an emulsion liquid membrane system
Authors: Zeng Lelin , Zhang Yi , Bukirwa Caroline , Li Wensong , Yang Yunquan
Published: October 2015

Mean diameter and drop size distribution of emulsion drops in a modified rotating disc contactor for an emulsion liquid membrane system.
Ab initio study of strained wurtzite InAs nanowires: engineering an indirect–direct band gap transition through size and uniaxial strain
Authors: Dabhi Shweta D. , Jha Prafulla K.
Published: October 2015

Size and strain dependent electronic properties of wurtzite InAs nanowires are investigated using density functional theory.
Efficient binary white light-emitting polymers grafted with iridium complexes as side groups
Authors: Guo Ting , Zhong Wenkai , Zou Jianhua , Ying Lei , Yang Wei , Peng Junbiao
Published: October 2015

Efficient binary white-light-emitting electrophosphorescent copolymers were designed and synthesized via Suzuki polymerization.
Microbead silica decorated with polyhedral silver nanoparticles as a versatile component of sacrificial gel films for SERS applications
Authors: Sarycheva Asia S. , Ivanov Vladimir K. , Baranchikov Alexander E. , Savilov Sergey V. , Sidorov Alexander V. , Goodilin Eugene A.
Published: October 2015

A new method of microbead silica preparation with polyhedral 20–50 nm silver nanoparticles encrusting silica surface. Such microengineered building blocks are stored safely in a sacrificial biopolymer (ethylcellulose) film.
Self assembled nanocages from DNA–protoporphyrin hybrid molecules
Authors: Singh Vandana , Monisha Mohan , Anindya Roy , Das Prolay
Published: October 2015

DNA–organic hybrid molecular building blocks are generated by covalent conjugation of the carboxyl groups of protoporphyrin IX with the amine functional groups of modified DNA oligomers.
The direct synthesis of symmetrical disulfides and diselenides by metal–organic framework MOF-199 as an efficient heterogenous catalyst
Authors: Soleiman-Beigi Mohammad , Yavari Issa , Sadeghizadeh Fatemeh
Published: October 2015

The MOF-199 was used as an efficient heterogeneous catalyst for the one-pot synthesis of organic disulfides/diselenides from aryl halides and elemental S/Se in polyethylene glycol (PEG) with good to excellent yields.
The real active sites over Zn–Cr catalysts for direct synthesis of isobutanol from syngas: structure-activity relationship
Authors: Tian Shaopeng , Wang Sichen , Wu Yingquan , Gao Junwen , Xie Hongjuan , Li Xiaoli , Yang Guohui , Han Yizhuo , Tan Yisheng
Published: October 2015

The isobutanol productivity is closely related to the cation disorder distribution.
The effect of zinc oxide (ZnO) addition on the physical and morphological properties of cellulose aerogel beads
Authors: Kamal Mohamed Seeni Meera , Ganesan Kathirvel , Milow Barbara , Ratke Lorenz
Published: October 2015

Microsized open porous cellulose aerogel beads were made using mixtures of NaOH and urea and its properties tuned by varying ZnO.
Methanol tolerant, high performance, noble metal free electrocatalyst developed from polyaniline and ferric chloride for the oxygen reduction reaction
Authors: Mutyala Sankararao , Mathiyarasu Jayaraman , Mulchandani Ashok
Published: October 2015

Here, we report a low-cost, noble metal free Fe–N–C catalyst prepared using carbonized polyaniline (PANI) and ferric chloride as precursors in an inert atmosphere for oxygen reduction reaction.
Bubble template synthesis of CdLa2S4 hollow spheres/reduced graphene oxide nanocomposites as efficient and sustainable visible-light driven photocatalysts
Authors: Zhu Lei , Oh Won-Chun
Published: October 2015

A hollow sphere CdLa2S4/reduced graphene oxide composite was successfully synthesized for the first time via a simple microwave assisted hydrothermal approach using bubbles generated from the decomposition of NH3H2O and Na2S2O3 in a domestic microwave within several minutes.
Microwave-assisted organic syntheses: microwave effect on intramolecular reactions – the Claisen rearrangement of allylphenyl ether and 1-allyloxy-4-methoxybenzene
Authors: Horikoshi Satoshi , Watanabe Tomoki , Kamata Momoko , Suzuki Yumiko , Serpone Nick
Published: October 2015

We examined the possible effect microwaves may have on intramolecular reactions such as the Claisen-type rearrangement process carried out in DMSO solvent and in solvent-free microwave irradiation conditions.
New insights into the phosphine-free synthesis of ultrasmall Cu2−xSe nanocrystals at the liquid–liquid interface
Authors: She Xing-jin , Zhang Qiang , Wang Cai-Feng , Chen Su
Published: October 2015

A liquid–liquid interfacial strategy to prepare ultra small (<5 nm) colloidal Cu2−​xSe NCs with blue-fluorescence, noncaustic and environmentally friendly NH4SCN replaces the long-chain organic ligands for fabrication of NC-sensitized solar.
Toward a robust porous coordination polymer: the inhibition of mutual movement between interpenetrating sub-networks by introduction of multiple C–H⋯π interactions
Authors: Jiang Xiang , Kou Hui-Zhong
Published: October 2015

We demonstrate that a robust porous coordination polymer can be achieved by introduction of multiple C–H⋯π interactions between diamonded sub-networks.
Sulfonated Schiff base copper(ii) complexes as efficient and selective catalysts in alcohol oxidation: syntheses and crystal structures
Authors: Hazra Susanta , Martins Luísa M. D. R. S. , Guedes da Silva M. Fátima C. , Pombeiro Armando J. L.
Published: October 2015

Alcohol oxidation properties of four copper complexes (2–5) derived from the sulfonated Schiff base H2L·3H2O (1) are described. A quantitative conversion of 1-phenylethanol was obtained with4within 20 min of low power MW irradiation.
Stability of zeolitic imidazolate frameworks: effect of forced water intrusion and framework flexibility dynamics
Authors: Grosu Yaroslav , Gomes Sandrine , Renaudin Guillaume , Grolier Jean-Pierre E. , Eroshenko Valentine , Nedelec Jean-Marie
Published: October 2015

Synergistic effect of temperature and pressure upon forced water intrusion strongly affects metal–organic frameworks stability.
Atomically dispersed Cu on Ce1−xRExO2−δ nanocubes (RE = La and Pr) for water gas shift: influence of OSC on catalysis
Authors: Ridwan Muhammad , Tamarany Rizcky , Han Jonghee , Nam Suk Woo , Ham Hyung Chul , Kim Jin Young , Choi Sun Hee , Jang Seong Cheol , Yoon Chang Won
Published: October 2015

To elucidate the effect of CeO2 shape and doping on WGS activity, Cu0.02Ce0.98O2−δ and Cu0.02Ce0.86RE0.12O2−δ (RE = La and Pr) were synthesized by a molecular precursor approach.
An improved catalytic effect of nitrogen-doped TiO2 nanofibers for rechargeable Li–O2 batteries; the role of oxidation states and vacancies on the surface
Authors: Agyeman Daniel Adjei , Song Kyeongse , Kang Seung Ho , Jo Mi Ru , Cho Eunbi , Kang Yong-Mook
Published: October 2015

This work demonstrates higher catalytic activity of nitrogen-doped TiO2 nanofibers for lithium-air cells compared to pristine TiO2. Its electrochemical superiority could be ascribed to electronic property changes on the surface.
Monodispersed PtNi nanoparticles deposited on diamine-alkalized graphene for highly efficient dehydrogenation of hydrous hydrazine at room temperature
Authors: Song Fu-Zhan , Zhu Qi-Long , Xu Qiang
Published: October 2015

Monodispersed PtNi nanoparticles (diameter ≤ 2.5 nm) were successfully immobilized on diamine-alkalized reduced graphene oxide, which exhibited a high activity (turnover frequency, 903 h−1at 303 K) for the catalytic dehydrogenation of hydrous hydrazine.
Copper substituted P2-type Na0.67CuxMn1−xO2: a stable high-power sodium-ion battery cathode
Authors: Kang Wenpei , Zhang Zhenyu , Lee Pui-Kit , Ng Tsz-Wai , Li Wenyue , Tang Yongbing , Zhang Wenjun , Lee Chun-Sing , Wai Yu Denis Yau
Published: October 2015

Plate-like copper-substituted P2-type Na0.67CuxMn1−xO2 is able to rapidly charge and discharge within 5 minutes while still giving a capacity of about 90 mA h g−1 at a current of 1000 mA g−1.
Tetraaryl pyrenes: photophysical properties, computational studies, crystal structures, and application in OLEDs
Authors: El-Assaad Tarek H. , Auer Manuel , Castañeda Raul , Hallal Kassem M. , Jradi Fadi M. , Mosca Lorenzo , Khnayzer Rony S. , Patra Digambara , Timofeeva Tatiana V. , Brédas Jean-Luc , List-Kratochvil Emil J. W. , Wex Brigitte , Kaafarani Bilal R.
Published: October 2015

Nine 1,3,6,8-tetraarylpyrenes were prepared and characterized for OLED-based blue-light emission.
HOXB5 induces invasion and migration through direct transcriptional up-regulation of β-catenin in human gastric carcinoma
Authors: Hong Chang-Soo , Jeong Oh , Piao Zhengri , Guo Chen , Jung Mi-Ran , Choi Chan , Park Young-Kyu
Published: October 2015

HOX (homeobox) genes encode a family of transcriptional regulators, which have an important role in morphogenesis and differentiation during embryonic development. Their deregulated expression is involved in the carcinogenesis of many human solid tumours. In the present study, we show that HOXB5 mRNA was significantly overexpressed in gastric cancer tissues compared with adjacent normal tissues. HOXB5-up-regulated cancer cells showed increased invasion and migration activity, but no change in proliferation activity, whereas HOXB5-down-regulated cells showed decreased invasion and migration activity. Up-regulation of HOXB5 resulted in up-regulation of β-catenin, whereas inhibition of HOXB5 expression by siRNA led to the down-regulation of β-catenin. Moreover, a significant correlation between HOXB5 and CTNNB1 (β-catenin) mRNA expression was detected in gastric cancer tissues. Furthermore, we found that HOXB5 binds directly to the CTNNB1 promoter region and activates the transcriptional expression of β-catenin, as well as its downstream target genes, encoding cyclin D1 and c-Myc, leading to an increase in the invasion and migration activity of human gastric cancer cells. Thus HOXB5 may be an important regulator of the Wnt/β-catenin signalling pathway, thereby contributing to gastric cancer progression and metastasis.
Fast Doppler rate estimation based on fourth‐order moment spectrum
Authors: Zhang Wei‐Qiang
Published: October 2015

A fast Doppler rate estimation method based on fourth‐order moment spectrum is presented. Without simultaneously estimating time delay, Doppler shift and Doppler rate, which is often time consuming, this method directly estimates the Doppler rate through maximisation the spectrum of the ratio of fourth‐order moments between the echo and source signals. Detailed computational implementation is given and the parameter is optimised via theoretical derivation. Computer simulations show the effectiveness of the proposed method.
Iterative detection supported by extrinsic information for holographic data storage systems
Authors: Nguyen C.D. , Lee J.
Published: October 2015

A new model in which an iterative detection is supported by extrinsic information from equalisers is proposed. Furthermore, the system performance involving extrinsic information from an opposite direction one‐dimensional soft output Viterbi algorithm is examined. The work is applied to holographic data storage (HDS) systems. The HDS systems are well known as a future storage system because of their extremely large storage capacity and high data transfer rates. However, the system faces two‐dimensional interference challenges. The results show that the proposed model vastly improves the performance of the HDS system under severe interference.
Hybrid OFDM experimentation based on arrayed waveguide grating for all‐optical FFT implementation in PON architecture
Authors: Morosi J. , Boffi P. , Martelli P. , Parolari P. , Cincotti G. , Shimizu S. , Wada N.
Published: October 2015

A hybrid optical frequency division multiplexing (OFDM) system based on the electrical generation of the OFDM signal at the transmitter and on the all‐optical demultiplexing of the OFDM subcarriers is experimentally demonstrated by exploiting a purposely designed arrayed waveguide grating (AWG) with 12.5 GHz frequency spacing. The AWG passively and all‐optically processes a 3‐subcarrier OFDM signal with fast Fourier transform functionalities, demultiplexing it into three 12.5 Gbit/s on–off keyed data at the corresponding output ports, which are then connected to the optical network users. Transmission over a 40 km feeder link is experimentally demonstrated. Taking into account the AWG's available 16 ports and four 3‐subcarrier OFDM signal generators modulating independent wavelength carriers, a passive optical network (PON) architecture can be realised serving 12 optical network units with 150 Gbit/s total aggregate downstream capacity.
Prediction of unplanned islanding using an energy based strategy
Authors: Kamali Sadegh , Amraee Turaj , Bathaee Seyed Mohammad Taghi
Published: October 2015

In this study a new index is proposed for power system islanding prediction. The total energy absorbed by coherent synchronous generators during unplanned islanding conditions is formulated as an islanding predictor. Decision tree (DT) algorithm is utilised to extract the information gain of the proposed predictor over the input training samples. A comprehensive list of input scenarios, including island and non‐island conditions is constructed. The rotor angles of synchronous generators are estimated by phasor measurements at generators’ terminals and used for calculating the predictor over the input samples. The results of DT algorithm are rearranged as a set of if–then rules for practical applications. The proposed method is implemented in the 10‐machine 39‐bus New‐England test system.
Recurrent multi‐objective differential evolution approach for reactive power management
Authors: Singh Himmat , Srivastava Laxmi
Published: October 2015

This study proposes a novel recurrent multi‐objective differential evolution (RMODE) algorithm to solve the constrained reactive power management (RPM) problem, which is a non‐linear, multi‐objective optimisation problem. Minimisation of total active power loss and improvement of voltage profile are considered as the objectives of the RPM problem. For RPM, generator bus voltage magnitudes, transformer tap settings and reactive power of capacitor/reactor are taken as the decision variables. In the proposed RMODE algorithm, the multi‐objective differential evolution (MODE) algorithm has been applied repeatedly using the available Pareto‐optimal solutions and re‐initialising the remaining population. Thus, for each next cycle of the RMODE, the better values of best compromise solution have been obtained. Effectiveness of the proposed RMODE algorithm has been demonstrated for RPM in the standard IEEE‐30 bus system and a practical 75‐bus Indian system. Compared with multi‐objective particle swarm optimisation (PSO), genetic algorithm toolbox for multi‐objective optimisation, MODE and reported results using modified differential evolution and classical PSO, the proposed approach seems to be a promising alternative approach for solving RPM problem in practical power system.
Multiple targets direction‐of‐arrival estimation in frequency scanning array antennas
Authors: Tehrani Mona Akbarniai , Laurin Jean Jacques , Savaria Yvon
Published: October 2015

In this study, the authors address the problem of resolving angular position of multiple targets in the same range and separated by less than an antenna beamwidth using frequency scanning array (FSA) antennas. First, the frequency scanning antenna signal model is derived and then the necessary compensation methods to overcome antenna pattern variations with frequency during the scan in FSAs are presented. Two direction‐of‐arrival (DOA) estimation algorithms, the minimum variance beamforming and the maximum‐likelihood estimation are applied on the signal model. Simulation results show that both methods can separate targets with angular separations smaller than a beamwidth by selecting correct parameters. The performance of the two DOA estimation methods with respect to different system parameters are investigated based on the signal model through Monte Carlo simulations and compared with the Cramér–Rao lower bound. In addition, an FSA antenna is presented in this work and simulations of the DOA estimation algorithms are performed using the measured antenna pattern of this antenna. The performance and limitations of target DOA estimation methods for the measured antenna patterns are also discussed.
Measuring the spin polarization of alkali-metal atoms using nuclear magnetic resonance frequency shifts of noble gases
Authors: Liu X. H. , Luo H. , Qu T. L. , Yang K. Y. , Ding Z. C.
Published: October 2015

We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of 87Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the 87Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the 87Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system.
Contributed Review: Application of voice coil motors in high-precision positioning stages with large travel ranges
Authors: Shan Guanqiao , Li Yingzi , Zhang Liwen , Wang Zhenyu , Zhang Yingxu , Qian Jianqiang
Published: October 2015

Recent interest in high-precision positioning stages with large travel ranges has sparked renewed attention to the development of voice coil motors (VCMs). Due to their large output force, VCMs can actuate more complicated flexure structures, eliminate rail friction, and improve positioning speed. The VCM structure is both compact and flexible; hence, it is convenient to design VCMs for a variety of stage structures. Furthermore, VCMs combined with other actuators are able to achieve large travel ranges with high precision. In this paper, we summarize the principles and control methods of a typical VCM, and we analyze its properties, including thrust force, acceleration, and response time. We then present recent research on high-precision VCM positioning stages with large travel ranges.
Blowup results for the KGS system with higher order Yukawa coupling
Authors: Shi Qi-Hong , Li Wan-Tong , Wang Shu
Published: October 2015

In this paper, we investigate the Klein-Gordon-Schrödinger (KGS) system with higher order Yukawa coupling in spatial dimensions N ≥ 3. We establish a perturbed virial type identity and prove blowup results relied on Lyapunov functionals for KGS system with a negative energy level. Additionally, we give a result with respect to the blowup rate in finite time for the radial solution in 3 spatial dimensions.
A reactor for high-throughput high-pressure nuclear magnetic resonance spectroscopy
Authors: Beach N. J. , Knapp S. M. M. , Landis C. R.
Published: October 2015

The design of a reactor for operando nuclear magnetic resonance (NMR) monitoring of high-pressure gas-liquid reactions is described. The Wisconsin High Pressure NMR Reactor (WiHP-NMRR) design comprises four modules: a sapphire NMR tube with titanium tube holder rated for pressures as high as 1000 psig (68 atm) and temperatures ranging from −90 to 90 °C, a gas circulation system that maintains equilibrium concentrations of dissolved gases during gas-consuming or gas-releasing reactions, a liquid injection apparatus that is capable of adding measured amounts of solutions to the reactor under high pressure conditions, and a rapid wash system that enables the reactor to be cleaned without removal from the NMR instrument. The WiHP-NMRR is compatible with commercial 10 mm NMR probes. Reactions performed in the WiHP-NMRR yield high quality, information-rich, and multinuclear NMR data over the entire reaction time course with rapid experimental turnaround.
The Lorentz anomaly via operator product expansion
Authors: Fredenhagen Stefan , Hoppe Jens , Hynek Mariusz
Published: October 2015

The emergence of a critical dimension is one of the most striking features of string theory. One way to obtain it is by demanding closure of the Lorentz algebra in the light-cone gauge quantisation, as discovered for bosonic strings more than forty years ago. We give a detailed derivation of this classical result based on the operator product expansion on the Lorentzian world-sheet.
A novel flexure-based vertical nanopositioning stage with large travel range
Authors: Zhu Xiaobo , Xu Xiao , Wen Zhijie , Ren Jiaqi , Liu Pinkuan
Published: October 2015

This paper presents the design of a novel flexure–based vertical (or Z–axis) nanopositioning stage driven by a piezoelectric actuator (PZT), which is capable of executing large travel range. The proposed stage consists mainly of a hybrid displacement amplification mechanism (DAM), a motion guiding mechanism, and a decoupling mechanism. The hybrid DAM with amplification ratio of 12.1 is developed to transfer the transverse motion of the PZT actuator into the vertical motion. The motion guiding mechanism is introduced to avoid cross coupling at the output end. The decoupling mechanism can significantly reduce the cross coupling at the driving end to protect the PZT. The stiffness and dynamics of the proposed stage are improved by these mechanisms. Analytical modeling and finite element analysis (FEA) are then adopted to optimize dimensions of the stage. Finally, a prototype of the stage is fabricated and tested for verification. The results of static and dynamic tests show that the proposed stage is capable of vertical travel range of 214 μm with resolution of 8 nm, and the first two resonance frequencies are 205 Hz and 1206 Hz, respectively. Cross coupling tests under various lateral loads (0 g–1000 g) show that the maximum variances of the lateral and angular cross couplings are less than 0.78 μm and 95 μrad, respectively, indicating good decoupling capability. In addition, the low–profile structure of the stage is well suited to be used in limited vertical space.
Effect of rotation and velocity shear on tearing layer stability in tokamak plasmas
Authors: White Ryan L. , Fitzpatrick Richard
Published: October 2015

Using a resistive generalization of the Frieman-Rotenberg formalism, the leading-order effects of velocity shear and rotation on linear tearing layer stability are studied for tokamak equilibria. The layer equations for resistive interchange modes are derived for arbitrary equilibrium rotation and velocity shear. The resulting layer equations do not conserve parity and are not simplified by Fourier transform. Thus, many standard numerical techniques cannot be implemented in a straightforward manner. Layer equations are also derived in the constant-Ψ limit. The constant-Ψ dispersion relation is obtained and is used to study the leading-order effects of rotation and velocity shear on the critical value of Δ′ required for tearing instability. It is found that rotation and velocity shear can couple with the parallel current and the current gradient in the layer to reduce Δ′crit. If parallel currents are sufficiently weak to compete with second-order effects, velocity shear can be stabilizing, while rotation is found to have a destabilizing effect. Second-order coupling of velocity shear and rotation can have either sign, and thus can affect stability in either direction.
Mechanism of cathode spot splitting in vacuum arcs in an oblique magnetic field
Authors: Beilis I. I.
Published: October 2015

Experiments in the last decade showed that for cathode spots in a magnetic field that obliquely intercepts the cathode surface, the current per spot increased with the transverse component of the magnetic field and decreased with the normal component. The present work analyzes the nature of cathode spot splitting in an oblique magnetic field. A physical model for cathode spot current splitting was developed, which considered the relation between the plasma kinetic pressure, self-magnetic pressure, and applied magnetic pressure in a current carrying cathode plasma jet. The current per spot was calculated, and it was found to increase with the tangential component of the magnetic field and to decrease with the normal component, which agrees well with the experimental dependence.
Self-aligned Ni/NiFe/Fe magnetic lateral heterostructures
Authors: Shimon G. , Ross C. A. , Adeyeye A. O.
Published: October 2015

The fabrication and magnetization reversal mechanism of a self-aligned Ni/Ni80Fe20/Fe lateral heterostructure (LH) are presented. Using a combination of angled deposition and multiple selective etching processes, high quality LHs are successfully fabricated consisting of an array of bi-component dots made of a lens and a crescent of two different materials surrounded by antidot of a third material. Three materials, Ni, NiFe, and Fe, are combined in different orders to make the lens, crescent, and antidot. In isolated bi-component dots without the antidot matrix, the region with lower MS first undergoes a single-domain reversal followed by the vortex nucleation-annihilation reversals of the region with higher MS. In the LH, the antidot matrix interacts magnetostatically with the bi-component dots and modifies the switching fields, with the reversal process depending on which material forms the antidot. The fabrication technique and the tunable reversal process presented in this work are useful for designing functional magnetoelectronic devices.
Optoelectronic properties of p-diamond/n-GaN nanowire heterojunctions
Authors: Schuster Fabian , Hetzl Martin , Weiszer Saskia , Wolfer Marco , Kato Hiromitsu , Nebel Christoph E. , Garrido Jose A. , Stutzmann Martin
Published: October 2015

In this work, nanodiodes comprised of n-GaN nanowires on p-diamond substrates are investigated. The electric transport properties are discussed on the basis of simulations and determined experimentally for individual p-diamond/n-GaN nanodiodes by applying conductive atomic force microscopy. For low doping concentrations, a high rectification ratio is observed. The fabrication of a prototype nanoLED device on the basis of ensemble nanowire contacts is presented, showing simultaneous electroluminescence in the UV and the green spectral range which can be ascribed to hole injection into the n-GaN nanowires and electron injection into the p-diamond, respectively. In addition, the operation and heat distribution of the nanoLED device are visualized by active thermographic imaging.
Thermal stability of deep level defects induced by high energy proton irradiation in n-type GaN
Authors: Zhang Z. , Farzana E. , Sun W. Y. , Chen J. , Zhang E. X. , Fleetwood D. M. , Schrimpf R. D. , McSkimming B. , Kyle E. C. H. , Speck J. S. , Arehart A. R. , Ringel S. A.
Published: October 2015

The impact of annealing of proton irradiation-induced defects in n-type GaN devices has been systematically investigated using deep level transient and optical spectroscopies. Moderate temperature annealing (>200–250 °C) causes significant reduction in the concentration of nearly all irradiation-induced traps. While the decreased concentration of previously identified N and Ga vacancy related levels at EC − 0.13 eV, 0.16 eV, and 2.50 eV generally followed a first-order reaction model with activation energies matching theoretical values for NI and VGa diffusion, irradiation-induced traps at EC − 0.72 eV, 1.25 eV, and 3.28 eV all decrease in concentration in a gradual manner, suggesting a more complex reduction mechanism. Slight increases in concentration are observed for the N-vacancy related levels at EC − 0.20 eV and 0.25 eV, which may be due to the reconfiguration of other N-vacancy related defects. Finally, the observed reduction in concentrations of the states at EC − 1.25 and EC − 3.28 eV as a function of annealing temperature closely tracks the detailed recovery behavior of the background carrier concentration as a function of annealing temperature. As a result, it is suggested that these two levels are likely to be responsible for the underlying carrier compensation effect that causes the observation of carrier removal in proton-irradiated n-GaN.
Analysis of local frequency response of flow to actuation: Application to the dielectric barrier discharge plasma actuator
Authors: Pereira Ricardo , Kotsonis Marios , de Oliveira Gaël , Ragni Daniele
Published: October 2015

The present study provides a methodology to derive the local frequency response of flow under actuation, in terms of the magnitude of actuator induced perturbations. The method is applied to a dielectric barrier discharge (DBD) plasma actuator but can be extended to other kinds of pulsed actuation. The actuator body force term is introduced in the Navier-Stokes equations, from which the flow is locally approximated with a linear-time-invariant system. The proposed semi-phenomenological model includes the effect of both viscosity and external flow velocity, providing a system response in the frequency domain. A validity criterium is additionally devised for the estimation of the threshold frequency below which the developed approach can be applied. Analytical results are compared with experimental data for a typical DBD plasma actuator operating in quiescent flow and in a laminar boundary layer. Good agreement is obtained between analytical and experimental results for cases below the model validity threshold frequency. Results demonstrate an efficient and simple approach towards prediction of the response of a convective flow to pulsed actuation.
Resonant energy transfer between Eu luminescent sites and their local geometry in GaN
Authors: Timmerman Dolf , Wakamatsu Ryuta , Tanaka Kazuteru , Lee Dong-gun , Koizumi Atsushi , Fujiwara Yasufumi
Published: October 2015

Eu-doped GaN is a solid state material with promising features for quantum manipulation. In this study, we investigate the population dynamics of Eu in ions in this system by resonant excitation. From differences in the emission related to transitions between the 5D0 and 7F2 manifold in the Eu ions, we can distinguish different luminescence sites and observe that a resonant energy transfer takes place between two of these sites which are in proximity of each other. The time constants related to this energy transfer are on the order of 100 μs. By using different substrates, the energy transfer efficiency could be strongly altered, and it is demonstrated that the coupling between ions has an out-of-plane character. Based on these results, a microscopic model of this combined center is presented.
Evidence and modeling of mechanoluminescence in a transparent glass particulate composite
Authors: Dubernet Marion , Gueguen Yann , Houizot Patrick , Célarié Fabrice , Sangleboeuf Jean-Christophe , Orain Hervé , Rouxel Tanguy
Published: October 2015

Mechanoluminescence (ML) of a transparent alkali-phosphate glass composite with SrAl2O4:Eu, Dy particles is reported. Uniaxial compression experiments show the linear dependence of the mechanoluminescence intensity with the mechanical power. A theoretical model, based on the physics of delayed processes (in analogy of viscoelasticity), is proposed. This model accurately predicts the ML intensity changes induced by a complex mechanical loading and provides a convincing description of the mechanoluminescence response.
Short channel field-effect transistors from ultrathin GaTe nanosheets
Authors: Xu Kai , Zhang Zhangyuan , Wang Zhenxing , Wang Feng , Huang Yun , Liao Lei , He Jun
Published: October 2015

The emergence of 2D layered materials provides a route for MOSFETs limited by short channel effects (SCEs). In this work, we investigate short channel transport behavior in ultrathin GaTe-based MOSFETs with channel lengths ranging from 1 μm down to 50 nm and then reveal the onset of SCEs in GaTe MOSFETs. Moreover, electrical transport measurements as a function of temperature dependence and gas absorption were conducted to modulate the SCEs. In addition, the behavior of GaTe MOSFETs was suppressed, evidently, by decreasing dielectric thickness. Our research provides the experimental groundwork for future applications of MOSFETs based on layered materials.
Ferroelectric control of anisotropic damping in multiferroic tunnel junctions
Authors: Wang Yan , Zhang Ning , Berakdar Jamal , Jia Chenglong
Published: October 2015

The magnetoelectric effect on nonlocal magnetization dynamics is theoretically investigated in normal-metal/ferroelectric-insulator/ferromagnetic tunnel junctions. In addition to the Rashba spin-orbit interaction (SOI) originating from loss of parity symmetry at the interfaces, the topology of interfacial spiral spins triggered by ferroelectric polarization acts with an effective SOI that is electrically controllable. These spin-dependent interactions result in an anisotropic Gilbert damping with C2v symmetry. The findings are of a direct relevance for the utilization of composite multiferroics for devices that rely on electrically controlled magnetic switching.
Enhanced inverse spin Hall contribution at high microwave power levels in La0.67Sr0.33MnO3/SrRuO3 epitaxial bilayers
Authors: Haidar S. M. , Shiomi Y. , Lustikova J. , Saitoh E.
Published: October 2015

We have investigated microwave power dependence of dc voltage generated upon ferromagnetic resonance in a La0.67Sr0.33MnO3/SrRuO3 epitaxial bilayer film at room temperature. With increasing microwave power above ∼75 mW, the magnitude of the voltage signal decreases as the sample temperature approaches the Curie temperature of La0.67Sr0.33MnO3 due to heating effects. By analyzing the dependence of the voltage signal on the direction of the magnetic field, we show that with increasing microwave power the contribution from the inverse spin Hall effect becomes more dominant than that from the anisotropic magnetoresistance effect.
Reversible adiabatic temperature changes at the magnetocaloric and barocaloric effects in Fe49Rh51
Authors: Stern-Taulats Enric , Gràcia-Condal Adrià , Planes Antoni , Lloveras Pol , Barrio Maria , Tamarit Josep-Lluís , Pramanick Sabyasachi , Majumdar Subham , Mañosa Lluís
Published: October 2015

We report on the adiabatic temperature changes (ΔT) associated with the magnetocaloric and barocaloric effects in a Fe49Rh51 alloy. For the magnetocaloric effect, data derived from entropy curves are compared to direct thermometry measurements. The agreement between the two sets of data provides support to the estimation of ΔT for the barocaloric effect, which are indirectly determined from entropy curves. Large ΔT values are obtained at relatively low values of magnetic field (2 T) and hydrostatic pressure (2.5 kbar). It is also shown that both magnetocaloric and barocaloric effects exhibit good reproducibility upon magnetic field and hydrostatic pressure cycling, over a considerable temperature range.
Low-temperature dynamics of ferroelectric domains in PbZr0.3Ti0.7O3 epitaxial thin films studied by piezoresponse force microscopy
Authors: Andreeva N. V. , Vakulenko A. F. , Petraru A. , Soni R. , Kohlstedt H. , Filimonov A. V. , Rudskoy A. I. , Vakhrushev S. B. , Pertsev N. A.
Published: October 2015

Dynamics of domain boundaries is expected to change drastically at low absolute temperatures but direct experimental information for this temperature range is still lacking. To clarify the mechanism of low-temperature domain dynamics, we studied the growth of ferroelectric domains in the temperature range 4.2–295 K using the out-of-plane piezoresponse mode of a cryogenic atomic force microscope (AFM). Nanoscale 180° domains were created in epitaxial PbZr0.3Ti0.7O3 films by applying short voltage pulses between the conductive AFM tip brought into contact with the bare film surface and the bottom LaSr0.7Mn0.3O3 electrode. A quantitative analysis of acquired piezoresponse images enabled us to determine the in-plane domain size as a function of the writing voltage and pulse duration. It is found that at all studied temperatures the dependence of this size on the pulse duration can be fitted by a logarithmic function, which indicates that the domain-wall velocity exponentially depends on the driving electric field. The theoretical analysis of experimental data shows that the observed low-temperature domain dynamics is consistent with the creep of domain boundaries occurring in the presence of defects and structural nanoheterogeneities.
Temperature dependent Raman spectroscopic study of mono-, bi-, and tri-layer molybdenum ditelluride
Authors: Park June , Kim Younghee , Jhon Young In , Jhon Young Min
Published: October 2015

We investigate the thermal properties of mono-, bi- and tri-layer MoTe2 by using temperature-dependent Raman spectroscopy ranging from 90 K to 300 K. The E2g1 and B2g1 modes of MoTe2 blueshift as the temperature decreases. The temperature dependence of the peak positions obtained from mono- to tri-layer MoTe2 is analyzed using the Grüneisen model. The first order temperature coefficients of E2g1 and B2g1 Raman modes of mono- to tri-layer MoTe2 are extracted. This study provides the fundamental information about the thermal properties of MoTe2 layers, which is crucial for developing thermal and electronic applications of MoTe2 based devices.
Dose‐Dependent, Therapeutic Potential of Angiotensin‐(1–7) for the Treatment of Pulmonary Arterial Hypertension
Authors: Breitling Siegfried , Krauszman Adrienn , Parihar Richa , Walther Thomas , Friedberg Mark K. , Kuebler Wolfgang M.
Published: October 2015

The effects of the heptapeptide angiotensin‐(1–7) (Ang‐(1–7)), via its receptor Mas, oppose many of the effects of the classic angiotensin II signaling pathway, and pharmacological exploitation of this effect is currently actively pursued for a wide range of cardiovascular, neoplastic, or immunological disorders. On the basis of its vasodilatory and antiproliferative properties, Ang‐(1–7) has consequentially also been proposed as a novel therapeutic strategy for the treatment of pulmonary arterial hypertension (PAH). In this study, we tested the effectiveness of Ang‐(1–7) and its stable, cyclic analog cAng‐(1–7) over a range of doses for their therapeutic potential in experimental PAH. In the monocrotaline (MCT) rat model of PAH, Ang‐(1–7) or cAng‐(1–7) were injected in doses of 30, 100, 300, or 900 μg kg–1 day–1, and effects on pulmonary hemodynamics and vascular remodeling were assessed. Five weeks after MCT injection, right ventricular systolic pressure (RVSP) was significantly reduced for 3 dose groups treated with Ang‐(1–7) (100, 300, and 900 μg kg–1 day–1) and for all dose groups treated with cAng‐(1–7), as compared to untreated controls, yet the total reduction of RVSP was >50% at best and thus markedly lower than that with a positive treatment control with ambrisentan. Medial‐wall thickness in pulmonary arterioles was only slightly reduced, without reaching significance, for any of the tested Ang‐(1–7) compounds and doses. The reported moderate attenuation of PAH does not confirm the previously postulated high promise of this strategy, and the therapeutic usefulness of Ang‐(1–7) may be limited in PAH relative to that in other cardiovascular diseases.
Modeling of fast neutral-beam-generated ions and rotation effects on RWM stability in DIII-D plasmas
Authors: Turco F. , Turnbull A. D. , Hanson J. M. , Navratil G. A.
Published: October 2015

Validation results for the MARS-K (Liu et al 2008 Phys. Plasmas
15 112503) code for DIII-D equilibria, predict that the absence of fast Neutral Beam (NB) generated ions leads to a plasma response ~40–60% higher than in NB-sustained H-mode plasmas when the no-wall β
N limit is reached. In a β
N scan, the MARS-K model with thermal and fast-ions, reproduces the experimental measurements above the no-wall limit, except at the highest β
N where the phase of the plasma response is overestimated. The dependencies extrapolate unfavourably to machines such as ITER with smaller fast ion fractions since elevated responses in the absence of fast ions indicate the potential onset of a resistive wall mode (RWM). The model was also tested for the effects of rotation at high β
N, and recovers the measured response even when fast-ions are neglected, reversing the effect found in lower β
N cases, but consistent with the higher β
N results above the no-wall limit. The agreement in the response amplitude and phase for the rotation scan is not as good, and additional work will be needed to reproduce the experimental trends. In the case of current-driven instabilities, the magnetohydrodynamic spectroscopy system used to measure the plasma response reacts differently from that for pressure driven instabilities: the response amplitude remains low up to ~93% of the current limit, showing an abrupt increase only in the last ~5% of the current ramp. This makes it much less effective as a diagnostic for the approach to an ideal limit. However, the mode structure of the current driven RWM extends radially inwards, consistent with that in the pressure driven case for plasmas with q
edge~2. This suggests that previously developed RWM feedback techniques together with the additional optimizations that enabled q
edge~2 operation, can be applied to control of both current-driven and pressure-driven modes at high β
N.
Target of rapamycin signaling mediates vacuolar fission caused by endoplasmic reticulum stress inSaccharomyces cerevisiae
Authors: Stauffer Bobbiejane , Powers Ted
Published: October 2015

The yeast vacuole is equivalent to the mammalian lysosome and, in response to diverse physiological and environmental stimuli, undergoes alterations both in size and number. Here we demonstrate that vacuoles fragment in response to stress within the endoplasmic reticulum (ER) caused by chemical or genetic perturbations. We establish that this response does not involve known signaling pathways linked previously to ER stress but instead requires the rapamycin-sensitive TOR Complex 1 (TORC1), a master regulator of cell growth, together with its downstream effectors, Tap42/Sit4 and Sch9. To identify additional factors required for ER stress–induced vacuolar fragmentation, we conducted a high-throughput, genome-wide visual screen for yeast mutants that are refractory to ER stress–induced changes in vacuolar morphology. We identified several genes shown previously to be required for vacuolar fusion and/or fission, validating the utility of this approach. We also identified a number of new components important for fragmentation, including a set of proteins involved in assembly of the V-ATPase. Remarkably, we find that one of these, Vph2, undergoes a change in intracellular localization in response to ER stress and, moreover, in a manner that requires TORC1 activity. Together these results reveal a new role for TORC1 in the regulation of vacuolar behavior.
FCGR2A and FCGR3A Genotypes in Human Immunodeficiency Virus Mother-to-Child Transmission
Authors: Milligan Caitlin , Richardson Barbra A. , John-Stewart Grace , Nduati Ruth , Overbaugh Julie
Published: October 2015

Background.  Fc-mediated effector functions have been suggested to influence human immunodeficiency virus (HIV) acquisition and disease progression. Analyzing the role of host Fc gamma receptor (FcγR) polymorphisms on HIV outcome in mother-to-child transmission (MTCT) will increase our understanding of how host genetics may alter immune responses in prevention, therapy, and disease. This study analyzed the impact of FCGR2A and FCGR3A genotypes on MTCT in a cohort in which Fc-mediated antibody functions are predictive of infant HIV outcome.

Methods.  Human immunodeficiency virus-positive mothers and their infants from a historical MTCT cohort were genotyped for FCGR2A and FCGR3A. We assessed the impact of these genotypes on transmission and acquisition of HIV and disease progression using χ2 tests, survival analyses, and logistic regression.

Results.  Among 379 mother-infant pairs, infant FCGR2A and FCGR3A genotypes were not associated with infant HIV infection or disease progression. Maternal FCGR2A was not associated with transmission, but there was a trend between maternal FCGR3A genotype and transmission (P = .07). When dichotomizing mothers into FCGR3A homozygotes and heterozygotes, heterozygotes had a 64.5% higher risk of transmission compared with homozygotes (P = .02). This risk was most evident in the early breastfeeding window, but a trend was only observed when restricting analyses to breastfeeding mothers (hazards ratio, 1.64; P = .064).

Conclusions.  Infant FCGR2A and FCGR3A genotypes were not associated with HIV infection or disease progression, and, thus, host FcγR genotype may not significantly impact vaccination or therapeutic regimens that depend on Fc-mediated antibody functions. Maternal FCGR3A genotype may influence early breastfeeding transmission risk, but more studies should be conducted to clarify this association and its mechanism.