bluuebunny/crossref_metadata_2025 huggingface dataset:
A highly selective synthesis of new alkenylsilsesquioxanes by hydrosilylation of alkynes
Authors: Franczyk A. , Stefanowska K. , Dutkiewicz M. , Frąckowiak D. , Marciniec B.
Published: November 2016

In this study a selective synthesis of a series of new di- and trisubstituted ethenes with a POSS moiety was performed.
Correction: Solar thermal decomposition of desalination reject brine for carbon dioxide removal and neutralisation of ocean acidity
Authors: Davies P. A.
Published: November 2016

Correction for ‘Solar thermal decomposition of desalination reject brine for carbon dioxide removal and neutralisation of ocean acidity’ by P. A. Davies, Environ. Sci.: Water Res. Technol., 2015, 1, 131–137.
Screening of deep eutectic solvents (DESs) as green CO2 sorbents: from solubility to viscosity
Authors: Sarmad Shokat , Xie Yujiao , Mikkola Jyri-Pekka , Ji Xiaoyan
Published: November 2016

35 novel DESs are synthesized and screened in terms of their CO2 solubility and viscosity.
Layer-by-layer assembly of porphyrin-based metal–organic frameworks on solids decorated with graphene oxide
Authors: Zvyagina Alexandra I. , Shiryaev Andrey A. , Baranchikov Alexander E. , Chernyshev Vladimir V. , Enakieva Yulia Yu. , Raitman Oleg A. , Ezhov Alexander A. , Meshkov Ivan N. , Grishanov Dmitry A. , Ivanova Olga S. , Gorbunova Yulia G. , Arslanov Vladimir V. , Kalinina Maria A.
Published: November 2016

Planar MOFs grow on graphene oxide templates.
One-pot synthesis of a ceria–graphene oxide composite for the efficient removal of arsenic species
Authors: Sakthivel Tamil S. , Das Soumen , Pratt Cameron J. , Seal Sudipta
Published: November 2016

Removal of arsenic contamination from water using a ceria–GO composite material prepared by a one-pot hydrothermal synthesis process.
The requirements at the C-3 position of alkylquinolones for signalling in Pseudomonas aeruginosa
Authors: Shanahan Rachel , Reen F. Jerry , Cano Rafael , O'Gara Fergal , McGlacken Gerard P.
Published: November 2016

The ‘perfect storm’ of increasing bacterial antibiotic resistance and a decline in the discovery of new antibiotics, has made it necessary to search for new and innovative strategies to treat bacterial infections.
Access to functionalized thienopyridines via a reagent-capsule-assisted coupling, thiolation and cyclization cascade sequence
Authors: Cai Jialing , Huang Shuo , He Ruenfa , Chen Lu , Chen Donghan , Jiang Shaohua , Li Bin , Li Yibiao
Published: November 2016

Thienopyridines and related heterocycles were prepared by a reagent-capsule-assisted palladium-catalyzed cross-coupling, thiolation and cyclization process in moderate to good yields.
Carbonylation as a novel method for the assembly of pyrazine based oligoamide alpha-helix mimetics
Authors: Van Mileghem Seger , Egle Brecht , Gilles Philippe , Veryser Cedrick , Van Meervelt Luc , De Borggraeve Wim M.
Published: November 2016

Carbonylative assembly of pyrazine based oligoamide alpha-helix mimetics.
Metal- and base-free reductive coupling reaction of P(O)–H with aryl/alkyl sulfonyl chlorides: a novel protocol for the construction of P–S–C bonds
Authors: Wang Dungai , Zhao Jinlong , Xu Weigang , Shao Changwei , Shi Zheng , Li Liang , Zhang Xinghua
Published: November 2016

Novel and efficient synthesis of S-aryl/alkyl phosphinothioates from P(O)–H and aryl/alkyl sulfonyl chlorides under metal- and base-free conditions is described.
π-Stacked poly(vinyl ketone)s with accumulated push–pull triphenylamine moieties in the side chain
Authors: Wang Heng , Wang Yue , Ye Xichong , Hayama Haruka , Sugino Hiroyoshi , Nakano Hideyuki , Nakano Tamaki
Published: November 2016

Poly(vinyl ketone)s bearing push–pull triphenyamine moiety indicated remarkable absorption hypochromism, reduced redox potentials, and emission red shifts due to a π-stacked conformation.
Liquid metal soft electrode triggered discharge plasma in aqueous solution
Authors: Yu Y. , Wang Q. , Wang X. L. , Wu Y. H. , Liu J.
Published: November 2016

This paper reports a fundamental phenomenon whereby discharge plasma can be easily triggered in aqueous solution under a low voltage via a liquid metal electrode that is either static or a jetting stream.
Raw product of rare-earth ore works as a high-k gate insulator for low-voltage operable organic field-effect transistors
Authors: She Xue-feng , Wang Jingsong , Xue Qingguo , Xu Wentao
Published: November 2016

Raw product of rare-earth ore was found to be good candidate for fabricating high-k gate insulator in field-effect transistors.
Effect of Mn doping on the activity and stability of Cu–SiO2catalysts for the hydrogenation of methyl acetate to ethanol
Authors: Ye Chenliang , Guo Cuili , Sun Chengwei , Zhang Yu
Published: November 2016

A series ofxMn–Cu–SiO2catalysts with different manganese contents were prepared by an ammonia-evaporation method for methyl acetate hydrogenation.
Correction: Structures, preparation and applications of titanium suboxides
Authors: Xu Baoqiang , Sohn Hong Yong , Mohassab Yousef , Lan Yuanpei
Published: November 2016

Correction for ‘Structures, preparation and applications of titanium suboxides’ by Baoqiang Xu et al., RSC Adv., 2016, 6, 79706–79722.
p-Type SnO thin layers on n-type SnS2 nanosheets with enriched surface defects and embedded charge transfer for lithium ion batteries
Authors: Zhang Yiqiong , Ma Zhaoling , Liu Dongdong , Dou Shuo , Ma Jianmin , Zhang Ming , Guo Zaiping , Chen Ru , Wang Shuangyin
Published: November 2016

We constructed defective heterointerfaces of p-SnO on n-SnS2 nanosheets by plasma treatment to improve the anode performance in Li-ion batteries.
Chiral nematic mesoporous magnetic ferrites
Authors: Meseck Georg R. , Terpstra Andrea S. , Marenco Armando J. , Trudel Simon , Hamad Wadood Y. , MacLachlan Mark J.
Published: November 2016

Hard templating of metal ferrites in the pores of a mesoporous silica yields nanomaterials with twisting magnetic structures. Using a variety of techniques, we demonstrate mesoporosity of the materials, the influence of calcination temperature on crystallinity and magnetic properties, and weak magnetic anisotropy.
Electronic transitions of the transparent delafossite-type CuGa1−xCrxO2 system: first-principles calculations and temperature-dependent spectral experiments
Authors: Wang Junyong , Zhang Peng , Deng Qinglin , Jiang Kai , Zhang Jinzhong , Hu Zhigao , Chu Junhao
Published: November 2016

The structure and optical properties of the CuGa1−xCrxO2 (CGCOx) system with 0 ≤ x ≤ 1 have been investigated by combining theoretical calculations and optical experiments.
A strategy to improve the thermoelectric performance of conducting polymer nanostructures
Authors: Zhao Jian , Tan Dongxing , Chen Guangming
Published: November 2016

The dependence of the PEDOT nanostructure’s thermoelectric performance on post-treatments with acid (H2SO4) and chemical reduction (Na2SO3) was reported.
Towards designing new nano-scale protein architectures
Authors: Aupič Jana , Lapenta Fabio , Strmšek Žiga , Jerala Roman
Published: November 2016

The complexity of designed bionano-scale architectures is rapidly increasing mainly due to the expanding field of DNA-origami technology and accurate protein design approaches. The major advantage offered by polypeptide nanostructures compared with most other polymers resides in their highly programmable complexity. Proteins allow in vivo formation of well-defined structures with a precise spatial arrangement of functional groups, providing extremely versatile nano-scale scaffolds. Extending beyond existing proteins that perform a wide range of functions in biological systems, it became possible in the last few decades to engineer and predict properties of completely novel protein folds, opening the field of protein nanostructure design. This review offers an overview on rational and computational design approaches focusing on the main achievements of novel protein nanostructure design.
Computationally efficient DOA estimation for monostatic MIMO radar based on covariance matrix reconstruction
Authors: Zhang Yu , Zhang Gong , Wang Xinhai
Published: November 2016

A computationally efficient direction‐of‐arrival (DOA) estimation algorithm for monostatic multiple‐input multiple‐output (MIMO) radar based on covariance matrix reconstruction is presented. By reduced‐dimension transformation, the transformed covariance matrix is reconstructed in the Toeplitz structure and then the DOAs are estimated by employing MUSIC. The proposed reduced‐complexity denosing covariance matrix reconstruction approach provides lower computational complexity compared with conventional two‐dimension multiple signal classification (2D‐MUSIC). Moreover, in contrast to the subspace‐based methods, the proposed method can be carried out without knowing the number of targets. Simulation results demonstrate the outperformance of the proposed method.
Modelling powder core inductors for passive filters in inverters using finite element analysis
Authors: Jayalath S. , Ongayo D. , Hanif M.
Published: November 2016

Properties of powder core based inductors when utilised in a passive filter of the voltage source inverter are investigated to highlight the importance of considering the soft‐saturation nature of powder materials in determining the inductance when subjected to varying load current. Simulations were carried out in ANSYS Maxwell and Simplorer to understand the magnetic behaviour of inductors under pulse width modulation in a three‐phase inverter. Variation of the effective inductance due to soft saturation nature of the powder cores is utilised to achieve the inductance demanded by the passive filter at the design stage.
Modification of the wireless power transfer system with Z‐source inverter
Authors: Wang Tianfeng , Liu Xin , Tang Houjun , Ali Muhammad
Published: November 2016

Adding the Z‐source inverter into wireless power transfer systems helps to offer more control strategies due to its extra state than the traditional inverter. However, the parameters of the system should be strictly designed, otherwise the system will malfunction. The malfunction issue and factor's causing it are described accordingly. Suggestions on the design parameters of the system are provided. To verify the analysis, simulation results of the proposed system are added.
Single‐layer single‐patch dual band antenna for satellite applications
Authors: Vijayvergiya Pushkar Lal , Panigrahi Rajib Kumar
Published: November 2016

A low profile, light weight, and low cost antenna for dual‐band operation in Ku‐band is presented for satellite applications. Antenna has broadside radiation pattern and it is a single‐layer and single‐patch antenna which has the added advantage of less complexity in realising the antenna. This dual‐band antenna meets the requirement of International Telecommunication Union for region 3. Lower and upper band of antenna include the frequency band for fixed satellite services (FSS) and direct broadcasting satellite for receive mode and FSS for transmit mode, respectively. The proposed design provide 10% and 8% bandwidth in lower and upper band, respectively, with a low frequency ratio of 1.2.
Effective supervised multiple‐feature learning for fused radar and optical data classification
Authors: karimi Danya , Akbarizadeh Gholamreza , Rangzan Kazem , Kabolizadeh Mostafa
Published: November 2016

In multi‐sensor data fusion based on multiple features, the high dimensionality of feature space increases the runtime and computational complexity. The present study proposes a new algorithm based on the combination of random subspace (RS), linear discriminant analysis and sparse regularisation (LDASR), namely RS–LDASR for feature space dimensionality reduction, supervised feature selection, and learning. The use of RSs can effectively solve the problem of high dimensionality and high feature‐to‐instance ratio. The extraction of multiple features from the images raises the possibility of a correlation between features which reduce classification accuracy. In this study, after the construction of several RSs, supervised feature selection and learning based on LDASR were applied with very high accuracy. Classification and image fusion for remote sensing data analysis were tested by the implementation of feature‐based fusion on two pairs of fused synthetic aperture radar and optical data. Four feature matrices were constructed using attribute profiles (APs), multi‐APs (MAPs), non‐negative matrix factorisation (NMF), and textural features. Support vector machine and rotation forest were applied as the base classifiers. The results show that use of RS–LDASR significantly improved the classification accuracy based on NMF plus texture features and even NMF alone.
Temperature-Controlled Continuous Cold Flow Device after Total Knee Arthroplasty: A Randomized Controlled Trial Study
Authors: Ruffilli Alberto , Traina Francesco , Corneti Isabella , Fenga Domenico , Giannini Sandro , Faldini Cesare , Castagnini Francesco
Published: November 2016

Total knee arthroplasty (TKA) is a widely accepted and successful procedure for end-stage arthritis. Nevertheless, fast-track may be compromised by many factors, such as pain, edema, and blood loss. Cryotherapy has been advocated as a safe and effective strategy to improve the postoperative results, acting on pain, edema, and blood loss. This study is a prospective randomized controlled study, involving 50 patients after primary TKA. A power analysis was performed preoperatively. Twenty-four patients were addressed to a postoperative treatment with a continuous cold flow device (Hilotherm, Hilotherm GmbH, Germany). Twenty-six patients represented the control group, treated with crushed ice packs. All the patients shared the same analgesic strategy and the same rehabilitation protocol. Pain, analgesic consumption, active knee range of motion, drain output, transfusion requirement, and total blood loss were evaluated at different follow-ups (postoperative first, third, and seventh days). The two groups were homogenous for preoperative and intraoperative features. The groups showed no statistically significant differences in all the evaluated parameters. A modest reduction of knee volume was evident after 7 days from surgery (trend). No differences in blood loss were noticed. Continuous cold flow device in the acute postoperative setting after TKA did not show superiority in reducing edema, pain, and blood loss, compared with traditional icing regimen. Thus, due to the costs, it should be reserved to selected cases.
Isoflurane-Associated Mydriasis Mimicking Blown Pupils in a Patient Treated in a Neurointensive Care Unit
Authors: Korf Eva , Tronnier Volker , Gliemroth Jan , Küchler Jan
Published: November 2016

We report a misinterpretation of bilateral mydriasis as blown pupils related to elevated intracranial pressure (ICP) under volatile sedation with isoflurane (Anesthetic Conserving Device [AnaConDa], Hudson RCI, Uppland Vasby, Sweden) in a 59-year-old patient with a severe traumatic brain injury with frontal contusion. The patient showed bilateral mydriasis and a missing light reflex 8 hours after changing sedation from intravenous treatment with midazolam and esketamine to volatile administration of isoflurane. Because cranial computed tomography ruled out signs of cerebral herniation, we assumed the bilateral mydriasis was caused by isoflurane and reduced the isoflurane supply. Upon this reduction the mydriasis regressed, suggesting the observed mydriasis was related to an overdose of isoflurane. Intensivists should be aware of the reported phenomenon to avoid unnecessary diagnostic investigations that might harm the patient. We recommend careful control of the isoflurane dose when fixed and dilated pupils appear in patients without other signs of elevated ICP.
Large piezoelectricity in electric-field modified single crystals of SrTiO3
Authors: Khanbabaee B. , Mehner E. , Richter C. , Hanzig J. , Zschornak M. , Pietsch U. , Stöcker H. , Leisegang T. , Meyer D. C. , Gorfman S.
Published: November 2016

Defect engineering is an effective and powerful tool to control the existing material properties and produce completely new ones, which are symmetry-forbidden in a defect-free crystal. For example, the application of a static electric field to a single crystal of SrTiO3 forms a strained near-surface layer through the migration of oxygen vacancies out of the area beneath the positively charged electrode. While it was previously shown that this near-surface phase holds pyroelectric properties, which are symmetry-forbidden in centrosymmetric bulk SrTiO3, this paper reports that the same phase is strongly piezoelectric. We demonstrate the piezoelectricity of this phase through stroboscopic time-resolved X-ray diffraction under alternating electric field and show that the effective piezoelectric coefficient d33 ranges between 60 and 100 pC/N. The possible atomistic origins of the piezoelectric activity are discussed as a coupling between the electrostrictive effect and spontaneous polarization of this near-surface phase.
Strong coupling effects on the relationship between internal energy and pressure for two-dimensional liquid dusty plasmas
Authors: Feng Yan , Li Wei , Wang Qiaoling , Lin Wei
Published: November 2016

Previously, the relationship between internal energy and pressure of two-dimensional (2D) strongly coupled liquid dusty plasmas was assumed to be approximately the same as that for the ideal gas [Oxtoby et al., Phys. Rev. Lett. 111, 015002 (2013)], which is a non-coupling system. To study the strong coupling effects on this relationship, the internal energy and pressure of 2D liquid dusty plasmas are obtained using equilibrium Yukawa molecular dynamics simulations. It is found that, for 2D Yukawa liquids, the internal energy and pressure follow a much more complicated relationship than that for the ideal gas. Especially at lower temperatures and for larger screening parameters, their relationship deviates from the ideal gas behavior much more. An analytical relationship between the internal energy and pressure for 2D Yukawa liquids has been obtained empirically by fitting.
Oscillating electric-field effects on adsorbed-water at rutile- and anatase-TiO2 surfaces
Authors: Futera Zdenek , English Niall J.
Published: November 2016

We have performed non-equilibrium molecular dynamics simulations of various TiO2/water interfaces at ambient temperature in presence of oscillating electric fields in frequency range 20–100 GHz and RMS intensities 0.05–0.25 V/Å. Although the externally applied fields are by one order of magnitude lower than the intrinsic electric field present on the interfaces (∼1.5–4.5 V/Å), significant non-thermal coupling of rotational and translational motion of water molecules was clearly observed. Enhancement of the motion, manifested by increase of diffusivity, was detected in the first hydration layer, which is known to be heavily confined by adsorption to the TiO2 surface. Interestingly, the diffusivity increases more rapidly on anatase than on rutile facets where the adsorbed water was found to be more organized and restrained. We observed that the applied oscillating field reduces number of hydrogen bonds on the interface. The remaining H-bonds are weaker than those detected under zero-field conditions; however, their lifetime increases on most of the surfaces when the low-frequency fields are applied. Reduction of adsorption interaction was observed also in IR spectra of interfacial water where the directional patterns are smeared as the intensities of applied fields increase.
Non-equilibrium dynamics from RPMD and CMD
Authors: Welsch Ralph , Song Kai , Shi Qiang , Althorpe Stuart C. , Miller Thomas F.
Published: November 2016

We investigate the calculation of approximate non-equilibrium quantum time correlation functions (TCFs) using two popular path-integral-based molecular dynamics methods, ring-polymer molecular dynamics (RPMD) and centroid molecular dynamics (CMD). It is shown that for the cases of a sudden vertical excitation and an initial momentum impulse, both RPMD and CMD yield non-equilibrium TCFs for linear operators that are exact for high temperatures, in the t = 0 limit, and for harmonic potentials; the subset of these conditions that are preserved for non-equilibrium TCFs of non-linear operators is also discussed. Furthermore, it is shown that for these non-equilibrium initial conditions, both methods retain the connection to Matsubara dynamics that has previously been established for equilibrium initial conditions. Comparison of non-equilibrium TCFs from RPMD and CMD to Matsubara dynamics at short times reveals the orders in time to which the methods agree. Specifically, for the position-autocorrelation function associated with sudden vertical excitation, RPMD and CMD agree with Matsubara dynamics up to O(t4) and O(t1), respectively; for the position-autocorrelation function associated with an initial momentum impulse, RPMD and CMD agree with Matsubara dynamics up to O(t5) and O(t2), respectively. Numerical tests using model potentials for a wide range of non-equilibrium initial conditions show that RPMD and CMD yield non-equilibrium TCFs with an accuracy that is comparable to that for equilibrium TCFs. RPMD is also used to investigate excited-state proton transfer in a system-bath model, and it is compared to numerically exact calculations performed using a recently developed version of the Liouville space hierarchical equation of motion approach; again, similar accuracy is observed for non-equilibrium and equilibrium initial conditions.
Self-consistent implementation of meta-GGA functionals for the ONETEP linear-scaling electronic structure package
Authors: Womack James C. , Mardirossian Narbe , Head-Gordon Martin , Skylaris Chris-Kriton
Published: November 2016

Accurate and computationally efficient exchange-correlation functionals are critical to the successful application of linear-scaling density functional theory (DFT). Local and semi-local functionals of the density are naturally compatible with linear-scaling approaches, having a general form which assumes the locality of electronic interactions and which can be efficiently evaluated by numerical quadrature. Presently, the most sophisticated and flexible semi-local functionals are members of the meta-generalized-gradient approximation (meta-GGA) family, and depend upon the kinetic energy density, τ, in addition to the charge density and its gradient. In order to extend the theoretical and computational advantages of τ-dependent meta-GGA functionals to large-scale DFT calculations on thousands of atoms, we have implemented support for τ-dependent meta-GGA functionals in the ONETEP program. In this paper we lay out the theoretical innovations necessary to implement τ-dependent meta-GGA functionals within ONETEP’s linear-scaling formalism. We present expressions for the gradient of the τ-dependent exchange-correlation energy, necessary for direct energy minimization. We also derive the forms of the τ-dependent exchange-correlation potential and kinetic energy density in terms of the strictly localized, self-consistently optimized orbitals used by ONETEP. To validate the numerical accuracy of our self-consistent meta-GGA implementation, we performed calculations using the B97M-V and PKZB meta-GGAs on a variety of small molecules. Using only a minimal basis set of self-consistently optimized local orbitals, we obtain energies in excellent agreement with large basis set calculations performed using other codes. Finally, to establish the linear-scaling computational cost and applicability of our approach to large-scale calculations, we present the outcome of self-consistent meta-GGA calculations on amyloid fibrils of increasing size, up to tens of thousands of atoms.
Minimum-exponents ansatz for molecular dynamics and quantum dissipation
Authors: Ding Jin-Jin , Zhang Hou-Dao , Wang Yao , Xu Rui-Xue , Zheng Xiao , Yan YiJing
Published: November 2016

A unified theory for minimum exponential-term ansatzes on bath correlation functions is proposed for numerically efficient and physically insightful treatments of non-Markovian environment influence on quantum systems. For a general Brownian oscillator bath of frequency Ω and friction ζ, the minimum ansatz results in the correlation function a bi-exponential form, with the effective Ω¯ and friction ζ¯ being temperature dependent and satisfying Ω¯/Ω=(ζ¯/ζ)1/2=r¯BO/rBO≤ 1, where r¯BO=ζ¯/(2Ω¯) and rBO=ζ/(2Ω). The maximum value of r¯BO=rBO can effectively be reached when kBT≥ 0.8Ω. The bi-exponential correlation function can further reduce to single-exponential form, in both the diffusion (rBO≫1) limit and the pre-diffusion region that could occur when rBO≥ 2. These are remarkable results that could be tested experimentally. Moreover, the impact of the present work on the efficient and accuracy controllable evaluation of non-Markovian quantum dissipation dynamics is also demonstrated.
Observation of in situ oxidation dynamics of vanadium thin film with ambient pressure X-ray photoemission spectroscopy
Authors: Kim Geonhwa , Yoon Joonseok , Yang Hyukjun , Lim Hojoon , Lee Hyungcheol , Jeong Changkil , Yun Hyungjoong , Jeong Beomgyun , Crumlin Ethan , Lee Jouhahn , Lee Jaeyoung , Ju Honglyoul , Mun Bongjin Simon
Published: November 2016

The evolution of oxidation/reduction states of vanadium oxide thin film was monitored in situ as a function of oxygen pressure and temperature via ambient pressure X-ray photoemission spectroscopy. Spectra analysis showed that VO2 can be grown at a relatively low temperature, T ∼ 523 K, and that V2O5 oxide develops rapidly at elevated oxygen pressure. Raman spectroscopy was applied to confirm the formation of VO2 oxide inside of the film. In addition, the temperature-dependent resistivity measurement on the grown thin film, e.g., 20 nm exhibited a desirable metal-insulator transition of VO2 with a resistivity change of ∼1.5 × 103 times at 349.3 K, displaying typical characteristics of thick VO2 film, e.g., 100 nm thick. Our results not only provide important spectroscopic information for the fabrication of vanadium oxides, but also show that high quality VO2 films can be formed at relatively low temperature, which is highly critical for engineering oxide film for heat-sensitive electronic devices.
Real-time energy measurement of high repetition rate ultrashort laser pulses using pulse integration and FPGA processing
Authors: Tang Qi-jie , Yang Dong-xu , Wang Jian , Feng Yi , Zhang Hong-fei , Chen Teng-yun
Published: November 2016

Real-time energy measurement using pulse integration method for high repetition rate ultrashort laser pulses based on FPGA (Field-Programmable Gate Array) and high-speed pipeline ADC (Analog-to-Digital Convertor) is introduced in this paper. There are two parts contained in this method: pulse integration and real-time data processing. The pulse integration circuit will convert the pulse to the step type signals which are linear to the laser pulse energy. Through the real-time data processing part, the amplitude of the step signals will be obtained by ADC sampling and conducting calculation in real time in FPGA. The test result shows that the method with good linearity (4.770%) and without pulse measurement missing is suitable for ultrashort laser pulses with high repetition rate up to 100 MHz.
Understanding the microsolvation of radicals: Infrared spectroscopy of benzyl radical water clusters
Authors: Leicht Daniel , Kaufmann Matin , Schwan Raffael , Schäfer Jan , Schwaab Gerhard , Havenith Martina
Published: November 2016

The IR spectrum of benzyl radical:water clusters was recorded. Benzyl radicals were produced by vacuum flash pyrolysis and trapped in superfluid helium nanodroplets. The infrared spectrum of benzyl radical water aggregates in the range 2585-2820 cm−1 was recorded by subsequent addition of deuterated water. A total of seven peaks are observed at 2766, 2750, 2656, 2638, 2633, 2598, and 2593 cm−1. Based on pressure dependent measurements and comparison to accompanying ab initio calculations, five of these bands are assigned to distinct O-D stretch vibrations of benzyl:water clusters with one and two water molecules. In line with previous experiments on benzene:water clusters, we observe the formation of a water dimer-like motif that is attached to one face of the benzyl radical.
Stability characteristics of Rayleigh-Taylor instability in a strongly coupled incompressible dust fluid with finite shear flow
Authors: Garai Sudip
Published: November 2016

The stability characteristics of Rayleigh-Taylor instability (RTI) has been investigated in an unmagnetized, strongly coupled dusty plasma in the presence of velocity shear. The description of the dust has been made through the Generalized Hydrodynamic model, where a strong correlation between the dust grains comes via the Maxwell relaxation time parameter. It has been found that when the correlations become stronger, the shear vortices that are originating from the Rayleigh-Taylor (RT) dynamics tend to propagate through the medium, giving a lesser opportunity to the RT mode to grow. Physically, in the strongly coupled regime, viscosity contributes to the dispersive correction, instead of normal dissipation in the RT mode and reduces the gravitational energy which is the main factor responsible for the RTI. In this process, shear flow also helps to stabilize the RT mode by extracting energy from the gravitational energy. Due to this combined effect, the long wavelength modes grow first and the shorter ones get completely suppressed. The results, first, have been obtained by local approximation and thereafter via nonlocal analysis with numerical techniques. A cut-off value of the wave vector, for the RT mode, has also been obtained analytically, which closely matches with the numerical one in the shorter wavelength regime.
Surface scattering controlled heat conduction in semiconductor thin films
Authors: Malhotra Abhinav , Maldovan Martin
Published: November 2016

Phonon-surface scattering is the fundamental mechanism behind thermal transport phenomena at the nanoscale. Despite its significance, typical approaches to describe the interaction of phonons with surfaces do not consider all relevant physical quantities involved in the phonon-surface interaction, namely, phonon momentum, incident angle, surface roughness, and correlation length. Here, we predict thermal conduction properties of thin films by considering an accurate description of phonon-surface scattering effects based on the rigorous Beckmann-Kirchhoff scattering theory extended with surface shadowing. We utilize a Boltzmann transport based reduced mean-free-path model for phonon transport in thin-films to predict the wavelength and mean-free-path heat spectra in Si and SiGe films for different surface conditions and show how the thermal energy distribution can be tailored by the surface properties. Using the predicted wavelength spectra, we also introduce a measure to quantify phonon-confinement effects and show an enhanced confinement in Ge alloyed Si thin films. The impact of surface roughness and correlation lengths on thermal conductivities is also studied, and our numerical predictions show excellent agreement with experimental measurements. The results allow to elucidate and quantitatively predict the amount of thermal energy carried by different phonons at the nanoscale, which can be used to design improved optoelectronic and thermoelectric devices.
Temperature dependent self-compensation in Al- and Ga-doped Mg0.05Zn0.95O thin films grown by pulsed laser deposition
Authors: Mavlonov Abdurashid , Richter Steffen , von Wenckstern Holger , Schmidt-Grund Rüdiger , Lorenz Michael , Grundmann Marius
Published: November 2016

We studied the doping efficiency of Al and Ga dopants in (Mg,Zn)O alloys as a function of the growth temperature and post growth annealing times. High-temperature growth results in the highest structural quality and highest electron mobility; the doping efficiency is limited by the dopant's solubility. It was investigated in detail that a low growth temperature is needed to achieve free carrier densities above the solubility limit of the dopants. Samples grown at temperatures of 300 °C and below have a free carrier density significantly above the solubility limit yielding the minimum resistivity of ρmin=4.8×10−4  Ω cm for Mg0.05Zn0.95O:Al thin films grown on glass at 300 °C. Annealing of these samples reduces the free carrier density and the absorption edge to values similar to those of samples grown at high temperatures. The saturation of the free carrier density and the optical bandgap at their high temperature growth/annealing values is explained by the thermal creation of acceptor-like compensating defects in thermodynamic equilibrium.
Symmetry restoring bifurcations and quasiperiodic chaos induced by a new intermittency in a vibro-impact system
Authors: Yue Yuan , Miao Pengcheng , Xie Jianhua , Celso Grebogi
Published: November 2016

Quasiperiodic chaos (QC), which is a combination of quasiperiodic sets and a chaotic set, is uncovered in the six dimensional Poincaré map of a symmetric three-degree of freedom vibro-impact system. Accompanied by symmetry restoring bifurcation, this QC is the consequence of a novel intermittency that occurs between two conjugate quasiperiodic sets and a chaotic set. The six dimensional Poincaré map P is the 2-fold composition of another virtual implicit map Q, yielding the symmetry of the system. Map Q can capture two conjugate attractors, which is at the core of the dynamics of the vibro-impact system. Three types of symmetry restoring bifurcations are analyzed in detail. First, if two conjugate chaotic attractors join together, the chaos-chaos intermittency induced by attractor-merging crisis takes place. Second, if two conjugate quasiperiodic sets are suddenly embedded in a chaotic one, QC is induced by a new intermittency between the three attractors. Third, if two conjugate quasiperiodic attractors connect with each other directly, they merge to form a single symmetric quasiperiodic one. For the second case, the new intermittency is caused by the collision of two conjugate quasiperiodic attractors with an unstable symmetric limit set. As the iteration number is increased, the largest finite-time Lyapunov exponent of the QC does not converge to a constant, but fluctuates in the positive region.
Reduction of cross-polarized reflection to enhance dual-band absorption
Authors: Kundu Debidas , Mohan Akhilesh , Chakrabarty Ajay
Published: November 2016

In this paper, cross-polarized reflection from a periodic array of metal-dielectric-metal resonator units is reduced to improve its absorbing performance. Through this simple and typical example, it is shown that some reported absorbers are actually poor absorbers but efficient polarization converters, when the cross-polarized reflection is considered. Using a frequency selective surface, sandwiched between the top layer and the ground plane, the cross-polarized reflection is reduced by 7.2 dB at 5.672 GHz and 8.5 dB at 9.56 GHz, while negligibly affecting the co-polarized reflection reduction performance. The polarization conversion ratio is reduced from 90. 74% to 34.12% and 98.51% to 27.2% and total absorption is improved up to 80% from 26% and 21% around the two resonant frequencies. The reflection characteristics of the proposed absorber are quantitatively analyzed using interference theory, where the near field coupling of the resonant geometries and ground is taken into account. Measurement results show good agreement with both the numerically simulated and theoretical results.
Understanding the atomic-scale friction in graphene: The distinction in behaviors of interlayer interactions during sliding
Authors: Wang Linfeng , Ma Tianbao , Hu Yuanzhong , Wang Hui
Published: November 2016

The atomic-scale friction in the graphene system is investigated from the interlayer interaction perspective using the density functional theory calculation including the dispersion correction. The structural effect brings a huge difference in friction between the commensurate and incommensurate states, and the interlayer interactions behavior quite differently as well. The van der Waals and π electron interactions, which comprise the interlayer interactions in the graphene system, act synergistically for the commensurate state. The energy barrier and hence friction are dominated by the van der Waals interaction for the relatively lower load, while the π electron interaction plays a more important role for the higher load. For the incommensurate state, the van der Waals interaction does not vary much during sliding, and the energy barrier and friction are mainly induced by the interaction between π electrons from different layers. The study increases our understanding on the interlayer interaction and friction mechanism in graphene and other carbon-based materials.
Low-temperature photoluminescence behaviour of Ag decorated ZnO Nanorods
Authors: Amutha A. , Amirthapandian S. , Sundaravel B. , Panigrahi B. K. , Saravanan K. , Thangadurai P.
Published: November 2016

The Ag nanoparticles decorated ZnO nanorods (Ag:ZnO) were prepared by irradiating the precursor solution with ultra-violet radiation for two irradiation times (6 and 17 h). Structural and microstructural studies were done by X-ray diffraction and transmission electron microscopy, respectively. Optical properties were studied by UV-Vis spectroscopy at room temperature (300 K) and photoluminescence (PL) spectroscopy at low-temperature in the temperature range from 5 to 300 K. The Ag:ZnO nanorods possessed the wurtzite structure of ZnO along with the cubic fcc phase of Ag nanoparticles. Average size of Ag nanoparticles in Ag:ZnO nanorods prepared with 6 and 17 h of UV irradiation time was 4 and 16 nm, respectively. The 4 nm Ag nanoparticles had played a crucial role for enhanced PL emission (in the UV region) in the Ag:ZnO nanorods at 60 K. In the case of 16 nm sized Ag nanoparticles, violet emission has been enhanced about 3.5 times compared to that of pure ZnO nanorods and 4 nm-Ag:ZnO nanorods at 5 K. Thermal activation energy of 4 nm-Ag:ZnO and 16 nm-Ag:ZnO nanorods was found to be 0.6 and 0.7 meV, respectively, at low temperature region (5 to 60 K).
First-principles study on stability and magnetism of NdFe11M and NdFe11MN for M = Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn
Authors: Harashima Yosuke , Terakura Kiyoyuki , Kino Hiori , Ishibashi Shoji , Miyake Takashi
Published: November 2016

Recently synthesized NdFe12N has excellent magnetic properties, while it is thermodynamically unstable. Using the first-principles method, we study the effect of substitutional 3d transition metal elements to the mother compound NdFe12. We find that Co has a positive effect on the stability of the ThMn12 structure. In contrast to Ti substitution, Co substitution does not reduce the magnetization significantly. The crystal field parameter 〈r2〉A20 is nearly unchanged by Co substitution, and nitrogenation to NdFe11Co greatly enhances 〈r2〉A20. This suggests that Co is a good candidate as a substitutional element for NdFe12N.
Stimulated emission via electron-hole plasma recombination in fully strained single InGaN/GaN heterostructures
Authors: Minj A. , Romero M. F. , Wang Y. , Tuna Ö. , Feneberg M. , Goldhahn R. , Schmerber G. , Ruterana P. , Giesen C. , Heuken M.
Published: November 2016

The optical properties of fully coherently grown single InGaN/GaN heterostructures for 12<In%<17 were investigated under low and high density excitations. At lower density, S-shape temperature dependence of the main emission peak, associated with localized exciton recombination was observed. The activation energy of the localized excitons remains invariable in the given range of In-contents. Most interestingly, under high density pulse-excitations, stimulated emission by electron-hole plasma recombination was observed for temperatures up to 295 K.
Low-current, narrow-linewidth microwave signal generation in NiMnSb based single-layer nanocontact spin-torque oscillators
Authors: Dürrenfeld P. , Gerhard F. , Mohseni S. M. , Ranjbar M. , Sani S. R. , Chung S. , Gould C. , Molenkamp L. W. , Åkerman J.
Published: November 2016

We report on the fabrication of nano-contact spin-torque oscillators based on single layers of the epitaxially grown half-metal NiMnSb with ultralow spin wave damping. We demonstrate magnetization auto-oscillations at microwave frequencies in the 1–3 GHz range in out-of-plane magnetic fields. Threshold current densities as low as 3 × 1011 A m−2 are observed as well as minimum oscillation linewidths of 200 kHz, both of which are much lower than the values achieved in conventional metallic spin-valve-based devices of comparable dimensions. These results enable the fabrication of spin transfer torque driven magnonic devices with low current density requirements, improved signal linewidths, and in a simplified single-layer geometry.
Enhanced kinetic stability of a bulk metallic glass by high pressure
Authors: Xue R. J. , Zhao L. Z. , Shi C. L. , Ma T. , Xi X. K. , Gao M. , Zhu P. W. , Wen P. , Yu X. H. , Jin C. Q. , Pan M. X. , Wang W. H. , Bai H. Y.
Published: November 2016

The metastable nature of metallic glasses (MGs) limits their applications. We report the formation of a stable Pd40.16Ni9.64Cu30.12P20.08 MG with bulk size under high pressure at room temperature. The stable MG shows remarkably enhanced thermal and kinetic stability with substantially increased glass transition temperature Tg, crystallization temperature Tx, density and mechanical properties. The unique stability can be further reinforced by higher pressure and maintained even above Tg. This result can advance the glass design and the understanding of the fundamental issues in MGs.
Morphology and crystalline-phase-dependent electrical insulating properties in tailored polypropylene for HVDC cables
Authors: Zha Jun-Wei , Yan Hong-Da , Li Wei-Kang , Dang Zhi-Min
Published: November 2016

Polypropylene (PP) has become one promising material to potentially replace the cross-link polyethylene used for high voltage direct current cables. Besides the isotactic polypropylene, the block polypropylene (b-PP) and random polypropylene (r-PP) can be synthesized through the copolymerization of ethylene and propylene molecules. In this letter, the effect of morphology and crystalline phases on the insulating electrical properties of PP was investigated. It was found that the introduction of polyethylene monomer resulted in the formation of β and γ phases in b-PP and r-PP. The results from the characteristic trap energy levels indicated that the β and γ phases could induce deep electron traps which enable to capture the carriers. And the space charge accumulation was obviously suppressed. Besides, the decreased electrical conductivity was observed in b-PP and r-PP. It is attributed to the existence of deep traps which can effectively reduce the carrier mobility and density in materials.
Giant third-order nonlinearity from low-loss electrochemical graphene oxide film with a high power stability
Authors: Ren Jun , Zheng Xiaorui , Tian Zhiming , Li Dan , Wang Pu , Jia Baohua
Published: November 2016

Giant third-order nonlinear absorption and refraction of electrochemical graphene oxide (EGO) film were investigated in the femtosecond regime using the single beam Z-scan technique. The excellent chemical stability of the EGO film under high-power illumination up to 400 mJ/cm2 is demonstrated, which can be attributed to the low oxidation degree revealed by the optical and Raman spectroscopies. High and broadband linear transmission over 70% has been observed from the visible to the infrared range. The low-loss EGO film with giant third-order nonlinearity, excellent chemical stability, large-scale preparation and flexible integration has a great potential for high-power nonlinear optical applications.
Out-of-plane polarization induced in magnetically-doped topological insulator Bi1.37V0.03Sb0.6Te2Se by circularly polarized synchrotron radiation above a Curie temperature
Authors: Shikin A. M. , Rybkina A. A. , Klimovskikh I. I. , Filianina M. V. , Kokh K. A. , Tereshchenko O. E. , Skirdkov P. N. , Zvezdin K. A. , Zvezdin A. K.
Published: November 2016

By means of angle- and spin-resolved photoemission, we demonstrate a possibility of the out-of-plane spin polarization of topological surface states and corresponding lifting of the Kramers degeneracy at the Dirac point induced in magnetically-doped topological insulator Bi1.37V0.03Sb0.6Te2Se by circularly polarized synchrotron radiation (SR) at room temperature. It has been shown that the induced out-of-plane polarization is created due to an “optically”-generated uncompensated spin accumulation with transferring the induced torque to the diluted V 3d ions. We have found theoretically a relation between the imbalance in depopulation of the Dirac cone states under photoexcitation, the generation of steady-state uncompensated spin accumulation and the induced magnetization that can be managed by the polarization of SR.
Stomatal behaviour under terminal drought affects post-anthesis water use in wheat
Authors: Saradadevi Renu , Bramley Helen , Palta Jairo A. , Siddique Kadambot H. M.
Published: November 2016

Post-anthesis water use is important for grain yield in wheat under drought because this water is immediately used for grain filling. The aim of this study was to determine whether root capacity for water uptake from deeper layers in the soil profile differed between two genotypes with contrasting stomatal behaviour under terminal drought. The wheat cultivar Drysdale and the breeding line IGW-3262 were grown in 1 m deep pots in a glasshouse under well-watered conditions until anthesis, when three watering treatments were imposed: (i) watering maintained at 90% pot soil water capacity (WW), (ii) watering withheld but supplementary watering supplied to the bottom 30 cm of the pot to keep this layer of the soil profile wet until physiological maturity (WB) and (iii) watering completely withheld (WS). Stomatal conductance, post-anthesis water use and water use efficiency, and grain yield were measured. Post-anthesis water use in Drysdale was similar in the WB and WW treatments, while in IGW-3262 it was 30% less in the WB treatment than in the WW treatment. In the WB treatment as the top soil dried, stomatal closure was faster in IGW-3262 than in Drysdale, which may have affected the capacity of roots to uptake available water at depth. The reduction in post-anthesis water use in IGW-3262 resulted in a decline in grain yield.
Stability, folding dynamics, and long-range conformational transition of the synaptic t-SNARE complex
Authors: Zhang Xinming , Rebane Aleksander A. , Ma Lu , Li Feng , Jiao Junyi , Qu Hong , Pincet Frederic , Rothman James E. , Zhang Yongli
Published: November 2016

Significance

Intracellular membrane fusion is mediated by coupled folding and assembly of three or four soluble
N
-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) proteins into a four-helix bundle. A rate-limiting step is the formation of a partial complex containing three helixes called the target (t)-SNARE complex on the target plasma membrane. The t-SNARE complex then serves as a template to guide stepwise zippering of the fourth helix, a process that is further regulated by other proteins. The synaptic t-SNARE complex readily misfolds. Consequently, its conformation, stability, and dynamics have not been well understood. Using optical tweezers and theoretical modeling, we elucidated the folding intermediates and kinetics of the t-SNARE complex and discovered a long-range conformational switch of t-SNAREs during SNARE zippering, which is essential for regulated SNARE assembly during synaptic vesicle fusion.