bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-assembly of ultrathin gold nanowires and single walled carbon nanotubes as a highly sensitive substrate for surface enhanced Raman spectroscopy
Authors: Zhang Yuanchao , Liu Jingquan , Li Da , Yan Fuhua , Wang Xin , Yang Wenrong
Published: July 2016

Self-assembly of ultrathin gold nanowires and single-walled carbon nanotubes as highly sensitive substrates for surface enhanced Raman spectroscopy.
Synthesis, structure and NMR studies of trinuclear Mo3S4 clusters coordinated with dithiophosphate and chiral carboxylate ligands
Authors: Gushchin Artem L. , Hernandez-Molina Rita , Anyushin Alexander V. , Gallyamov Marsel R. , Gonzalez-Platas Javier , Moroz Nikolay K. , Sokolov Maxim N.
Published: July 2016

Introducing chirality into the Mo3S4 cluster has been achieved through coordination of (S)-mandelate and (S)-phenyllactate ligands affording new complexes as a pair of diastereoisomers, (PS) and (MS), represented in the scheme.
One-pot synthesis of gold nanodimers and their use as surface-enhanced Raman scattering tags
Authors: Vilar-Vidal Noelia , Bonhommeau Sébastien , Talaga David , Ravaine Serge
Published: July 2016

Gold dimers consisting of 40 nm-diameter nanospheres show enhancement factors as high as ∼1.8 × 107at the hot-spot level.
Novel non-spherical deltahedra in trirhenaborane structures
Authors: Attia Amr A. A. , Lupan Alexandru , King R. Bruce
Published: July 2016

Low-energy Cp3Re3Bn−3Hn−3 (7 ≤ n ≤ 12) structures are found to be Re3Bn−3 deltahedra with internally bonded Re3 triangles. The rhenium atoms are generally located at degree 6 to 8 vertices and the boron atoms at degree 3 to 5 vertices. Low-energy Cp3Re3B2H2 and Cp3Re3B3H3 structures are found to be trigonal bipyramids and bicapped tetrahedra, respectively.
Palladium-catalysed direct C-2 methylation of indoles
Authors: Tu Daoquan , Cheng Xiuzhi , Gao Yadong , Yang Panpan , Ding Yousong , Jiang Chao
Published: July 2016

A direct C-2 methylation reaction of indoles bearing an N-2-pyrimidyl directing group has been developed with a palladium catalyst.
Functionalized microporous organic nanotube networks as a new platform for highly efficient heterogeneous catalysis
Authors: Zhang Hui , Xiong Linfeng , He Zidong , Zhong Aiqing , Wang Tianqi , Xu Yang , Zhou Minghong , Huang Kun
Published: July 2016

A novel amino-functionalized microporous organic nanotube networks (NH2-MONNs) as heterogeneous base catalyst was successfully synthesized by combination of hyper-cross-linking and molecular templating of multicomponent bottlebrush copolymers.
Aggregation and surface behavior of aqueous solutions of cis-bis(1,3-diaminopropane)bis(dodecylamine)cobalt(iii) nitrate. A double-chained metallosurfactant
Authors: Wagay T. A. , Dey J. , Kumar S. , Aswal V. K. , Ismail K.
Published: July 2016

Metallosurfactants or amphiphilic metal complexes are emerging as a new class of material with a range of properties inherent to both metal complexes and surfactants.
Mn and As doping of β-FeSi2via a chemical method
Authors: Sen S. , Guha P. K. , Banerji P. , Pramanik P.
Published: July 2016

β-FeSi2 has been doped with Mn and As by chemical reduction which results in uniform doping and hence cost-effectiveness.
Biological behavior of bioactive glasses and their composites
Authors: Zahid Saba , Shah Asma Tufail , Jamal Arshad , Chaudhry Aqif Anwar , Khan Abdul Samad , Khan Ather Farooq , Muhammad Nawshad , Rehman Ihtesham ur
Published: July 2016

This review summarizes current developments in improving the biological behavior of bioactive glasse and their composites.
Effect of RGO deposition on chemical and mechanical reliability of Ag nanowire flexible transparent electrode
Authors: Hwang B. , Park M. , Kim T. , Han S. M.
Published: July 2016

The role of RGO in chemical and mechanical reliability was studied for Ag nanowire/RGO hybrid electrode. RGO deposition can be effective in reducing the oxidation while maintaining the superior mechanical reliability under cyclic bendings.
One-pot synthesis of uniform and monodisperse superparamagnetic molecularly imprinted polymer nanospheres through a sol–gel process for selective recognition of bisphenol A in aqueous media
Authors: Chang Tingting , Liu Yuxin , Yan Xiangyang , Liu Shaomin , Zheng Haisong
Published: July 2016

Uniform and monodisperse Fe3O4@MIP nanospheres were directly synthesized using a sol–gel method on the surface of Fe3O4–COOH spheres.
Dielectric properties of pyridine–ethanol mixtures: density functional theory and experiments
Authors: Wu Zhiyan , Huang Kama , Kuang Xiaoyu
Published: July 2016

The schematic of the experimental system.
Surface adsorption of triblock copolymer (PEO–PPO–PEO) on cellulose nanocrystals and their melt extrusion with polyethylene
Authors: Nagalakshmaiah Malladi , Pignon Frédéric , El Kissi Nadia , Dufresne Alain
Published: July 2016

Cellulose nanocrystals (CNC) have gained a lot of interest in recent years in the field of composites due to their unique mechanical properties and also because cellulose is the most abundant and renewable polymer in nature.
A new more atom-efficient multi-component approach to tetrasubstituted imidazoles: one-pot condensation of nitriles, amines and benzoin
Authors: Khalafi-Nezhad Ali , Shekouhy Mohsen , Sharghi Hashem , Aboonajmi Jasem , Zare Abdolkarim
Published: July 2016

A new more atom-efficient multi-component approach for the synthesis of tetrasubstituted imidazoles via the one-pot condensation of nitriles, primary amines and benzoin has been described.
Theoretical studies of the function switch and mechanism of AceK as a highly active ATPase
Authors: Qin Jiajia , Tan Hongwei , Li Xichen , Chen Guangju , Zheng Jimin , Wang Ye , Ma Jianqiu , Jia Zongchao
Published: July 2016

As a multi-function enzyme, AceK integrates kinase, phosphatase and ATPase activities in a single active site and these functions are delicately regulated..
Thermogravimetric study of sequential carbonation and decarbonation processes over Na2ZrO3at low temperatures (30–80 °C): relative humidity effect
Authors: Mendoza-Nieto J. Arturo , Pfeiffer Heriberto
Published: July 2016

Na2ZrO3was synthetizedviasolid-state and tested in a low temperature range (30–80 °C) for carbonation and decarbonation processes using RH values between 0 and 80%. Results confirm that it is possible to accomplish successively at least 8 cycles.
Hierarchical self-assembled nanoclay derived mesoporous CNT/polyindole electrode for supercapacitors
Authors: Oraon Ramesh , De Adhikari Amrita , Tiwari Santosh Kumar , Bhattacharyya Srijit , Chandra Nayak Ganesh
Published: July 2016

A series of self-assembled and open interconnected mesoporous CNT/polyindole (Pind) electrodes were synthesized by a facile in situ & ex situ approach in the presence of layered silicate material for energy storage application.
The electronic structure and spin–orbit-induced spin splitting in antimonene with vacancy defects
Authors: Yang Lifang , Song Yan , Mi Wenbo , Wang Xiaocha
Published: July 2016

We study the geometric, electronic properties, and spin splitting in monovacancy (MV) and divacancy (DV) antimonene with five different models using first-principles calculations.
Multiple overlap extension PCR (MOE-PCR): an effective technical shortcut to high throughput synthetic biology
Authors: Kadkhodaei Saeid , Memari Hamid Rajabi , Abbasiliasi Sahar , Rezaei Morvarid Akhavan , Movahedi Ali , Shun Tan Joo , Ariff Arbakariya Bin
Published: July 2016

The current study describes multiple-overlap-extension PCR (MOE-PCR) as a simple and effective approach to assembling multiple DNA fragments with various sizes and features in a single in vitro reaction.
Dual-band photodetector with a hybrid Au-nanoparticles/β-Ga2O3 structure
Authors: An Y. H. , Guo D. Y. , Li Z. M. , Wu Z. P. , Zhi Y. S. , Cui W. , Zhao X. L. , Li P. G. , Tang W. H.
Published: July 2016

Lower dark current, higher photoresponse and faster switching time under a 254 nm light illumination and dual-band are obtained for a photodetector through the introduction of Au-NPs.
High performance planar perovskite solar cells with a perovskite of mixed organic cations and mixed halides, MA1−xFAxPbI3−yCly
Authors: Isikgor Furkan H. , Li Bichen , Zhu Hai , Xu Qinghua , Ouyang Jianyong
Published: July 2016

Planar heterojunction perovskite solar cells with MA1−xFAxPbI3−yCly can exhibit a high power conversion efficiency (PCE) of up to 18.14%.
Rational synthesis of a novel 3,3,5-c polyhedral metal–organic framework with high thermal stability and hydrogen storage capability
Authors: Liu Jianqiang , Liu Guoliang , Gu Chuying , Liu Weicong , Xu Jingwen , Li Baohong , Wang Wenjing
Published: July 2016

By using a functionalized ligand strategy, an uncommon (3,3,5)-c polyhedron-based metal–organic framework named GDMU-2 has been constructed, which has a high H2 uptake of 240.7 cm3 g−1 (2.16 wt%) at 77 K and 1 bar.
Water dispersible siloxane nanogels: a novel technique to control surface characteristics and drug release kinetics
Authors: Saraswathy Manju , Stansbury Jeffrey , Nair Devatha
Published: July 2016

Amphiphilic, water-dispersible, crosslinked siloxane nanogels were synthesized and applied as optically clear, functional coatings on the surface of lens substrates to demonstrate the feasibility of siloxane-nanogels to generate covalently tethered coatings and modify the surface properties of intraocular lens substrates.
Acoustic–Phonetic Versus Lexical Processing in Nonnative Listeners Differing in Their Dominant Language
Authors: Shi Lu-Feng , Koenig Laura L.
Published: July 2016

Purpose

Nonnative listeners have difficulty recognizing English words due to underdeveloped acoustic–phonetic and/or lexical skills. The present study used Boothroyd and Nittrouer's (1988)
j
factor to tease apart these two components of word recognition.

Method

Participants included 15 native English and 29 native Russian listeners. Fourteen and 15 of the Russian listeners reported English (ED) and Russian (RD) to be their dominant language, respectively. Listeners were presented 119 consonant–vowel–consonant real and nonsense words in speech-spectrum noise at +6 dB SNR. Responses were scored for word and phoneme recognition, the logarithmic quotient of which yielded
j
.

Results

Word and phoneme recognition was comparable between native and ED listeners but poorer in RD listeners. Analysis of
j
indicated less effective use of lexical information in RD than in native and ED listeners. Lexical processing was strongly correlated with the length of residence in the United States.

Conclusions

Language background is important for nonnative word recognition. Lexical skills can be regarded as nativelike in ED nonnative listeners. Compromised word recognition in ED listeners is unlikely a result of poor lexical processing. Performance should be interpreted with caution for listeners dominant in their first language, whose word recognition is affected by both lexical and acoustic–phonetic factors.
The Client's Perspective on Voluntary Stuttering
Authors: Byrd Courtney T. , Gkalitsiou Zoi , Donaher Joe , Stergiou Erin
Published: July 2016

Purpose

Voluntary stuttering is a strategy that has been suggested for use in the clinical literature but has minimal empirical data regarding treatment outcomes. The purpose of the present study is to explore client perspectives regarding the impact of the use of this strategy on the affective, behavioral, and cognitive components of stuttering.

Method

The present study used an original survey designed to explore the intended purpose. A total of 206 adults who stutter were included in the final data corpus. Responses were considered with respect to the type of voluntary stuttering the participants reportedly produced and the location of use.

Results

A client perceives significantly greater affective, behavioral, and cognitive benefits from voluntary stuttering when the production is closely matched to the client's actual stutter and when it is used outside the clinical environment.

Conclusions

To enhance client perception of associated benefits, clinicians should encourage use of voluntary stuttering that closely matches the client's own stuttering. Clinicians should also facilitate practice of voluntary stuttering outside of the therapy room. Finally, clinicians should be aware that clients, at least initially, may not perceive any benefits from the use of this strategy.
Current sensor fault detection and isolation method for PMSM drives, using average normalised currents
Authors: Khojet El Khil S. , Jlassi I. , Estima J.O. , Mrabet‐Bellaaj N. , Marques Cardoso A.J.
Published: July 2016

A new approach for current sensor fault detection and isolation (FDI) for permanent magnet synchronous motor (PMSM) drives is presented. Contrary to the classical approaches for sensors fault diagnosis, based on residual generation through observers or parity equations, the proposed technique uses the average normalised machine‐phase currents. The main advantages of this approach are that it does not need any information about the PMSM or inverter models, and it involves low tuning efforts, that make it suitable for real‐time implementation with good reliability. The good performance and the robustness of the proposed FDI approach are illustrated through experimental results.
Fully automatic figure‐ground segmentation algorithm based on deep convolutional neural network and GrabCut
Authors: Fu Ruigang , Li Biao , Gao Yinghui , Wang Ping
Published: July 2016

Figure‐ground segmentation is used to extract the foreground from the background, where the foreground is usually defined as the region containing the most meaningful object of the image. In fact, the algorithms that take advantage of human–computer interaction often attain better performance and they are based on the ‘one‐to‐one’ model. In this study, the authors present a novel algorithm for figure‐ground segmentation based on the GrabCut algorithm, which is a common segmentation algorithm that is user interactive. However, instead of a real user, they attempt to use a pre‐trained deep convolutional neural network to interact with GrabCut for completing its job successfully. Weizmann's segmentation evaluation database is used as the test dataset and the results show that their algorithm works well for figure‐ground segmentation. While the previous automatic segmentation algorithms are required to rank their segments empirically in order to find the position of the foreground after the segmentation, their algorithm is fully automatic.
Design of a high efficiency relativistic backward wave oscillator with low guiding magnetic field
Authors: Li Xiaoze , Song Wei , Tan Weibing , Zhang Ligang , Su Jiancang , Zhu Xiaoxin , Hu Xianggang , Shen Zhiyuan , Liang Xu , Ning Qi
Published: July 2016

A high efficiency relativistic backward wave oscillator working at a low guiding magnetic field is designed and simulated. A trapezoidal resonant reflector is used to reduce the modulation field in the resonant reflector to avoid overmodulation of the electron beam which will lead to a large momentum spread and then low conversion efficiency. The envelope of the inner radius of the slow wave structure (SWS) increases stepwise to keep conformal to the trajectory of the electron beam which will alleviate the bombardment of the electron on the surface of the SWS. The length of period of the SWS is reduced gradually to make a better match between phase velocity and electron beam, which decelerates continually and improves the RF current distribution. Meanwhile the modulation field is reduced by the introduction of nonuniform SWS also. The particle in cell simulation results reveal that a microwave with a power of 1.8 GW and a frequency of 14.7 GHz is generated with an efficiency of 47% when the diode voltage is 620 kV, the beam current 6.1 kA, and the guiding magnetic field 0.95 T.
Characteristic length scale of the magnon accumulation in Fe3O4/Pt bilayer structures by incoherent thermal excitation
Authors: Anadón A. , Ramos R. , Lucas I. , Algarabel P. A. , Morellón L. , Ibarra M. R. , Aguirre M. H.
Published: July 2016

The dependence of Spin Seebeck effect (SSE) with the thickness of the magnetic materials is studied by means of incoherent thermal excitation. The SSE voltage signal in Fe3O4/Pt bilayer structure increases with the magnetic material thickness up to 100 nm, approximately, showing signs of saturation for larger thickness. This dependence is well described in terms of a spin current pumped in the platinum film by the magnon accumulation in the magnetic material. The spin current is generated by a gradient of temperature in the system and detected by the Pt top contact by means of inverse spin Hall effect. Calculations in the frame of the linear response theory adjust with a high degree of accuracy the experimental data, giving a thermal length scale of the magnon accumulation (Λ) of 17 ± 3 nm at 300 K and Λ = 40 ± 10 nm at 70 K.
Thermal transport in porous Si nanowires from approach-to-equilibrium molecular dynamics calculations
Authors: Cartoixà Xavier , Dettori Riccardo , Melis Claudio , Colombo Luciano , Rurali Riccardo
Published: July 2016

We study thermal transport in porous Si nanowires (SiNWs) by means of approach-to-equilibrium molecular dynamics simulations. We show that the presence of pores greatly reduces the thermal conductivity, κ, of the SiNWs as long mean free path phonons are suppressed. We address explicitly the dependence of κ on different features of the pore topology—such as the porosity and the pore diameter—and on the nanowire (NW) geometry—diameter and length. We use the results of the molecular dynamics calculations to tune an effective model, which is capable of capturing the dependence of κ on porosity and NW diameter. The model illustrates the failure of Matthiessen's rule to describe the coupling between boundary and pore scattering, which we account for by the inclusion of an additional empirical term.
Determination of absolute value of quantum efficiency of radiation in high quality GaN single crystals using an integrating sphere
Authors: Kojima Kazunobu , Ohtomo Tomomi , Ikemura Ken-ichiro , Yamazaki Yoshiki , Saito Makoto , Ikeda Hirotaka , Fujito Kenji , Chichibu Shigefusa F.
Published: July 2016

Omnidirectional photoluminescence (ODPL) measurement using an integrating sphere was carried out to absolutely quantify the quantum efficiency of radiation (η) in high quality GaN single crystals. The total numbers of photons belonging to photoluminescence (PL photons) and photons belonging to an excitation source (excitation photons) were simultaneously counted in the measurement, and η was defined as a ratio of the number of PL photons to the number of absorbed excitation photons. The ODPL spectra near the band edge commonly showed a two-peak structure, which originates from the sharp absorption edge of GaN. A methodology for quantifying internal quantum efficiency (ηint) from such experimentally obtained η is derived. A record high ηint of typically 15% is obtained for a freestanding GaN crystal grown by hydride vapor phase epitaxy on a GaN seed crystal synthesized by the ammonothermal method using an acidic mineralizer, when the excitation photon energy and power density were 3.81 eV and 60 W/cm2, respectively.
Thermal conductivity measurement of amorphous dielectric multilayers for phase-change memory power reduction
Authors: Fong S. W. , Sood A. , Chen L. , Kumari N. , Asheghi M. , Goodson K. E. , Gibson G. A. , Wong H.-S. P.
Published: July 2016

In this work, we investigate the temperature-dependent thermal conductivities of few nanometer thick alternating stacks of amorphous dielectrics, specifically SiO2/Al2O3 and SiO2/Si3N4. Experiments using steady-state Joule-heating and electrical thermometry, while using a micro-miniature refrigerator over a wide temperature range (100–500 K), show that amorphous thin-film multilayer SiO2/Si3N4 and SiO2/Al2O3 exhibit through-plane room temperature effective thermal conductivities of about 1.14 and 0.48 W/(m × K), respectively. In the case of SiO2/Al2O3, the reduced conductivity is attributed to lowered film density (7.03 → 5.44 × 1028 m–3 for SiO2 and 10.2 → 8.27 × 1028 m–3 for Al2O3) caused by atomic layer deposition of thin-films as well as a small, finite, and repeating thermal boundary resistance (TBR) of 1.5 m2 K/GW between dielectric layers. Molecular dynamics simulations reveal that vibrational mismatch between amorphous oxide layers is small, and that the TBR between layers is largely due to imperfect interfaces. Finally, the impact of using this multilayer dielectric in a dash-type phase-change memory device is studied using finite-element simulations.
Ultrarelativistic bound states in the spherical well
Authors: Żaba Mariusz , Garbaczewski Piotr
Published: July 2016

We address an eigenvalue problem for the ultrarelativistic (Cauchy) operator (−Δ)1/2, whose action is restricted to functions that vanish beyond the interior of a unit sphere in three spatial dimensions. We provide high accuracy spectral data for lowest eigenvalues and eigenfunctions of this infinite spherical well problem. Our focus is on radial and orbital shapes of eigenfunctions. The spectrum consists of an ordered set of strictly positive eigenvalues which naturally splits into non-overlapping, orbitally labelled E(k,l) series. For each orbital label l = 0, 1, 2, …, the label k = 1, 2, … enumerates consecutive lth series eigenvalues. Each of them is 2l + 1-degenerate. The l = 0 eigenvalues series E(k,0) are identical with the set of even labeled eigenvalues for the d = 1 Cauchy well: E(k,0)(d = 3) = E2k(d = 1). Likewise, the eigenfunctions ψ(k,0)(d = 3) and ψ2k(d = 1) show affinity. We have identified the generic functional form of eigenfunctions of the spherical well which appear to be composed of a product of a solid harmonic and of a suitable purely radial function. The method to evaluate (approximately) the latter has been found to follow the universal pattern which effectively allows to skip all, sometimes involved, intermediate calculations (those were in usage, while computing the eigenvalues for l ≤ 3).
Four-dimensional (4D) tracking of high-temperature microparticles
Authors: Wang Zhehui , Liu Q. , Waganaar W. , Fontanese J. , James D. , Munsat T.
Published: July 2016

High-speed tracking of hot and molten microparticles in motion provides rich information about burning plasmas in magnetic fusion. An exploding-wire apparatus is used to produce moving high-temperature metallic microparticles and to develop four-dimensional (4D) or time-resolved 3D particle tracking techniques. The pinhole camera model and algorithms developed for computer vision are used for scene calibration and 4D reconstructions. 3D positions and velocities are then derived for different microparticles. Velocity resolution approaches 0.1 m/s by using the local constant velocity approximation.
Impurity effects on trapped electron mode in tokamak plasmas
Authors: Du Huarong , Wang Zheng-Xiong , Dong J. Q.
Published: July 2016

The effects of impurity ions on the trapped electron mode (TEM) in tokamak plasmas are numerically investigated with the gyrokinetic integral eigenmode equation. It is shown that in the case of large electron temperature gradient (ηe), the impurity ions have stabilizing effects on the TEM, regardless of peaking directions of their density profiles for all normalized electron density gradient R/Lne. Here, R is the major radius and Lne is the electron density gradient scale length. In the case of intermediate and/or small ηe, the light impurity ions with conventional inwardly (outwardly) peaked density profiles have stabilizing effects on the TEM for large (small) R/Lne, while the light impurity ions with steep inwardly (outwardly) peaked density profiles can destabilize the TEM for small (large) R/Lne. Besides, the TEM driven by density gradient is stabilized (destabilized) by the light carbon or oxygen ions with inwardly (outwardly) peaked density profiles. In particular, for flat and/or moderate R/Lne, two independent unstable modes, corresponding respectively to the TEM and impurity mode, are found to coexist in plasmas with impurity ions of outwardly peaked density profiles. The high Z tungsten impurity ions play a stronger stabilizing role in the TEM than the low Z impurity ions (such as carbon and oxygen) do. In addition, the effects of magnetic shear and collision on the TEM instability are analyzed. It is shown that the collisionality considered in this work weakens the trapped electron response, leading to a more stable TEM instability, and that the stabilizing effects of the negative magnetic shear on the TEM are more significant when the impurity ions with outwardly peaked density profile are taken into account.
Influence of a falling edge on high power microwave pulse combination
Authors: Li Jiawei , Huang Wenhua , Zhu Qi , Xiao Renzhen , Shao Hao
Published: July 2016

This paper presents an explanation of the influence of a microwave falling edge on high-power microwave pulse combination. Through particle-in-cell simulations, we discover that the falling edge is the driving factor that limits the output power of the combined pulses. We demonstrate that the space charge field, which accumulates to become comparable to the E-field at the falling edge of the former pulse, will trap the electrons in the gas layer and decrease its energy to attain a high ionization rate. Hence, avalanche discharge, caused by trapped electrons, makes the plasma density to approach the critical density and cuts off the latter microwave pulse. An X-band combination experiment is conducted with different pulse intervals. This experiment confirms that the high density plasma induced by the falling edge can cut off the latter pulse, and that the time required for plasma recombination in the transmission channel is several microseconds. To ensure a high output power for combined pulses, the latter pulse should be moved ahead of the falling edge of the former one, and consequently, a beat wave with high peak power becomes the output by adding two pulses with normal amplitudes.
Hydraulic jumps in inhomogeneous strongly coupled toroidal dust flows
Authors: Piel Alexander , Wilms Jochen
Published: July 2016

The inhomogeneous flow of strongly coupled dust particles in a toroidal particle trap with harmonic radial confinement is analyzed in the incompressible fluid limit. It is shown that the flow can spontaneously generate shock-like events, which are similar to the hydraulic jump in open channel flows. A definition of the Froude number for this model is given and the critical speed is recovered as the group velocity of surface waves. This hydraulic model is compared with molecular-dynamics simulations, which show that a sudden bifurcation of the flow lines and a localized temperature peak appear just at the point where the critical condition for the hydraulic jump is located.
GHz spurious mode free AlN lamb wave resonator with high figure of merit using one dimensional phononic crystal tethers
Authors: Wu Guoqiang , Zhu Yao , Merugu Srinivas , Wang Nan , Sun Chengliang , Gu Yuandong
Published: July 2016

This letter reports a spurious mode free GHz aluminum nitride (AlN) lamb wave resonator (LWR) towards high figure of merit (FOM). One dimensional gourd-shape phononic crystal (PnC) tether with large phononic bandgaps is employed to reduce the acoustic energy dissipation into the substrate. The periodic PnC tethers are based on a 1 μm-thick AlN layer with 0.26 μm-thick Mo layer on top. A clean spectrum over a wide frequency range is obtained from the measurement, which indicates a wide-band suppression of spurious modes. Experimental results demonstrate that the fabricated AlN LWR has an insertion loss of 5.2 dB and a loaded quality factor (Q) of 1893 at 1.02 GHz measured in air. An impressive ratio of the resistance at parallel resonance (Rp) to the resistance at series resonance (Rs) of 49.8 dB is obtained, which is an indication of high FOM for LWR. The high Rp to Rs ratio is one of the most important parameters to design a radio frequency filter with steep roll-off.
Symmetry-based coding method and synthesis topology optimization design of ultra-wideband polarization conversion metasurfaces
Authors: Sui Sai , Ma Hua , Wang Jiafu , Feng Mingde , Pang Yongqiang , Xia Song , Xu Zhuo , Qu Shaobo
Published: July 2016

In this letter, we propose the synthesis topology optimization method of designing ultra-wideband polarization conversion metasurface for linearly polarized waves. The general design principle of polarization conversion metasurfaces is derived theoretically. Symmetry-based coding, with shorter coding length and better optimization efficiency, is then proposed. As an example, a topological metasurface is demonstrated with an ultra-wideband polarization conversion property. The results of both simulations and experiments show that the metasurface can convert linearly polarized waves into cross-polarized waves in 8.0–30.0 GHz, obtaining the property of ultra-wideband polarization conversion based on metasurfaces, and hence validating the synthesis design method. The proposed method combines the merits of topology optimization and symmetry-based coding method, which provides an efficient tool for the design of high-performance polarization conversion metasurfaces.
The influence of projectile ion induced chemistry on surface pattern formation
Authors: Karmakar Prasanta , Satpati Biswarup
Published: July 2016

We report the critical role of projectile induced chemical inhomogeneity on surface nanostructure formation. Experimental inconsistency is common for low energy ion beam induced nanostructure formation in the presence of uncontrolled and complex contamination. To explore the precise role of contamination on such structure formation during low energy ion bombardment, a simple and clean experimental study is performed by selecting mono-element semiconductors as the target and chemically inert or reactive ion beams as the projectile as well as the source of controlled contamination. It is shown by Atomic Force Microscopy, Cross-sectional Transmission Electron Microscopy, and Electron Energy Loss Spectroscopy measurements that bombardment of nitrogen-like reactive ions on Silicon and Germanium surfaces forms a chemical compound at impact zones. Continuous bombardment of the same ions generates surface instability due to unequal sputtering and non-uniform re-arrangement of the elemental atom and compound. This instability leads to ripple formation during ion bombardment. For Argon-like chemically inert ion bombardment, the chemical inhomogeneity induced boost is absent; as a result, no ripples are observed in the same ion energy and fluence.
Electric field control of magnetic anisotropy in the easy cone state of Ta/Pt/CoFeB/MgO structures
Authors: Park Kyung-Woong , Park June-Young , Baek Seung-heon Chris , Kim Dae-Hoon , Seo Soo-Man , Chung Sung-Woong , Park Byong-Guk
Published: July 2016

The electric-field control of magnetic anisotropy is of particular interest because it allows the manipulation of the magnetization direction in spintronic devices with high performance and low power consumption. In this work, we investigate the effect of an electric field on the magnetic anisotropy in Ta/Pt/CoFeB/MgO structures, whose easy axis of magnetization is canted from the z-axis, forming a cone state. When an electric field is applied to the sample, its anisotropy constants change, thus modulating the cone state. It is demonstrated that the cone angle is controlled between 22° and 32° by a bias field of 4 MV/cm and that it can persist even after removing the bias. Moreover, it fully recovers to the original value when a bias voltage with an opposite polarity is applied. The non-volatile and reversible control of the cone state paves the way towards the utilization of the magnetic cone state in spintronic devices.
The Boersch effect in a picosecond pulsed electron beam emitted from a semiconductor photocathode
Authors: Kuwahara Makoto , Nambo Yoshito , Aoki Kota , Sameshima Kensuke , Jin Xiuguang , Ujihara Toru , Asano Hidefumi , Saitoh Koh , Takeda Yoshikazu , Tanaka Nobuo
Published: July 2016

The space charge effect has been clearly observed in the energy distributions of picosecond pulse beams from a spin-polarized electron microscope, and was found to depend upon the quantity of charge per pulse. The non-linear phenomena associated with this effect have also been replicated in beam simulations that take into account of a three-dimensional space charge. The results show that a charge of 500 aC/pulse provides the highest brightness with a 16-ps pulse duration, a 30-keV beam energy, and an emission spot of 1.8 μm. Furthermore, the degeneracy of the wave packet of the pulsed electron beam has been evaluated to be 1.6 × 10−5 with a charge of 100 aC/pulse, which is higher than that for a continuously emitted electron beam despite the low beam energy of 30 keV. The high degeneracy and high brightness contribute to the realization of high temporal and energy resolutions in low-voltage electron microscopy, which will serve to reduce radiolysis damage and enhance scattering contrast.
Carrier relaxation in (In,Ga)As quantum dots with magnetic field-induced anharmonic level structure
Authors: Kurtze H. , Bayer M.
Published: July 2016

Sophisticated models have been worked out to explain the fast relaxation of carriers into quantum dot ground states after non-resonant excitation, overcoming the originally proposed phonon bottleneck. We apply a magnetic field along the quantum dot heterostructure growth direction to transform the confined level structure, which can be approximated by a Fock–Darwin spectrum, from a nearly equidistant level spacing at zero field to strong anharmonicity in finite fields. This changeover leaves the ground state carrier population rise time unchanged suggesting that fast relaxation is maintained upon considerable changes of the level spacing. This corroborates recent models explaining the relaxation by polaron formation in combination with quantum kinetic effects.
Electric field-induced coexistence of nonvolatile resistive and magnetization switching in Pt/NiO/Nb:SrTiO3 heterostructure
Authors: Zhao Meng , Zhu Yongdan , Wang Qiangwen , Wei Maocai , Liu Xiaolian , Zhang Feng , Hu Cheng , Zhang Tingting , Qiu Da , Li Meiya , Xiong Rui
Published: July 2016

We report the coexistence of nonvolatile resistive and magnetization switching in Pt/NiO/Nb:SrTiO3 heterostructures. These structures exhibit bipolar resistive switching (RS) behavior with multilevel RS characteristics, a maximum RS ratio of 105, and stable endurance properties. Under simple application of voltage pulses, the saturation magnetization of the NiO layer increases by up to three times in the different resistance states. This electrical modulation of both the resistive and magnetization switching properties is attributed to the migration of oxygen vacancies and charge trapping and detrapping at the heterojunction interface. Our results provide a pathway towards the electrical switching of both resistance and magnetization, which is likely to be useful for RS and magnetic multifunctional device applications.
Laser pushing or pulling of absorbing airborne particles
Authors: Wang Chuji , Gong Zhiyong , Pan Yong-Le , Videen Gorden
Published: July 2016

A single absorbing particle formed by carbon nanotubes in the size range of 10–50 μm is trapped in air by a laser trapping beam and concurrently illuminated by another laser manipulating beam. When the trapping beam is terminated, the movement of the particle controlled by the manipulating beam is investigated. We report our observations of light-controlled pushing and pulling motions. We show that the movement direction has little relationship with the particle size and manipulating beam's parameters but is dominated by the particle's orientation and morphology. With this observation, the controllable optical manipulation is now able to be generalized to arbitrary particles, including irregularly shaped absorbing particles that are shown in this work.
The dielectric function of weakly ionized dusty plasmas
Authors: Li Hui , Wu Jian , Zhou Zhong-Xiang , Yuan Chengxun , Jia Jieshu
Published: July 2016

Using classical Boltzmann kinetic theory, the dielectric function of weakly ionized unmagnetized dusty plasma is derived. The elastic Coulomb collision and inelastic charging collision of electrons with charged dust particle as well as charge variation on dust surface are taken into account. The theoretical result is applied to analyze the propagation of electromagnetic wave in a dusty plasma. It is demonstrated that the additional collision mechanism provided by charged dust particle can significantly increase the absorbed power of electromagnetic wave. These increases are mainly determined by the dust radius, density, and the charge numbers on the dust surface. The obtained results will support an enhanced understanding of the wave propagation processes in space and laboratory dusty plasmas.
A high-efficiency relativistic magnetron with the filled dielectric
Authors: Wang Xiao-Yu , Fan Yu-Wei , Shi Di-fu , Shu Ting
Published: July 2016

Relativistic magnetron (RM) is a popular high power microwave device. Filling the resonant cavities with the low-loss dielectric is a well-proven technology that improves the performance of RM. In order to enhance the power efficiency, a dielectric-filled relativistic magnetron (DFRM) is presented and investigated numerically with KARAT code in this paper. The simulation results indicate that the maximum power efficiency is enhanced from 50.0% in the conventional RM to 56.0% in the DFRM when the applied voltage and the magnetic field are 280 kV and 0.5 T, respectively. Besides, the simulation results are analyzed and discussed.
Perpendicular magnetic anisotropy in Co2Fe0.4Mn0.6Si
Authors: Ludbrook B. M. , Ruck B. J. , Granville S.
Published: July 2016

We report perpendicular magnetic anisotropy (PMA) in the half-metallic ferromagnetic Heusler alloy Co2Fe0.4Mn0.6Si (CFMS) in a MgO/CFMS/Pd trilayer stack. PMA is found for CFMS thicknesses between 1 and 2 nm, with a magnetic anisotropy energy density of KU=1.5×106 erg/cm3 for tCFMS=1.5 nm. Both the MgO and Pd layer are necessary to induce the PMA. We measure a tunable anomalous Hall effect, where its sign and magnitude vary with both the CFMS and Pd thickness.
Effects of size and concentration on diffusion-induced stress in lithium-ion batteries
Authors: Ma Zengsheng , Gao Xiang , Wang Yan , Lu Chunsheng
Published: July 2016

Capacity fade of lithium-ion batteries induced by chemo-mechanical degradation during charge-discharge cycles is the bottleneck in design of high-performance batteries, especially high-capacity electrode materials. Stress generated due to diffusion-mechanical coupling in lithium-ion intercalation and deintercalation is accompanied by swelling, shrinking, and even micro-cracking. In this paper, we propose a theoretical model for a cylindrical nanowire electrode by combining the bond-order-length-strength and diffusion theories. It is shown that size and concentration have a significant influence on the stress fields in radial, hoop, and axial directions. This can explain why a smaller electrode with a huge volume change survives in the lithiation/delithiation process.
Radiation pressure acceleration of protons to 93 MeV with circularly polarized petawatt laser pulses
Authors: Kim I. Jong , Pae Ki Hong , Choi Il Woo , Lee Chang-Lyoul , Kim Hyung Taek , Singhal Himanshu , Sung Jae Hee , Lee Seong Ku , Lee Hwang Woon , Nickles Peter V. , Jeong Tae Moon , Kim Chul Min , Nam Chang Hee
Published: July 2016

The radiation pressure acceleration (RPA) of charged particles has been a challenging task in laser-driven proton/ion acceleration due to its stringent requirements in laser and target conditions. The realization of radiation-pressure-driven proton acceleration requires irradiating ultrathin targets with an ultrahigh contrast and ultraintense laser pulses. We report the generation of 93-MeV proton beams achieved by applying 800-nm 30-fs circularly polarized laser pulses with an intensity of 6.1×1020 W/cm2 to 15-nm-thick polymer targets. The radiation pressure acceleration was confirmed from the obtained optimal target thickness, quadratic energy scaling, polarization dependence, and three-dimensional particle-in-cell simulations. We expect this clear demonstration of RPA to facilitate the realization of laser-driven proton/ion sources delivering energetic and short-pulse particle beams for novel applications.
Mo(CO)6 as a Solid CO Source in the Synthesis of Aryl/Heteroaryl Weinreb Amides under Microwave-Enhanced Condition
Authors: Ningegowda Raghu , Bhaskaran Savitha , Sajith Ayyiliath M. , Aswathanarayanappa Chandrashekar , Padusha M. Syed Ali , Shivananju Nanjunda Swamy , Priya Babu Shubha
Published: July 2016

The facile transformation of aryl/heteroaryl nonaflates into corresponding amides via Pd-catalyzed aminocarbonylation using Mo(CO)6 as a solid CO source under microwave-enhanced condition is reported. The method was found to be tolerant with respect to a diverse range of electronically biased aryl/heteroaryl nonaflates, and exceptional yields were obtained. The optimized protocol was further extended to a diverse range of amines.
Composite 3D-printed metastructures for low-frequency and broadband vibration absorption
Authors: Matlack Kathryn H. , Bauhofer Anton , Krödel Sebastian , Palermo Antonio , Daraio Chiara
Published: July 2016

Significance

Architected material used to control elastic wave propagation has thus far relied on two mechanisms for forming band gaps, or frequency ranges that cannot propagate: (
i
) Phononic crystals rely on their structural periodicity to form Bragg band gaps, but are limited in the low-frequency ranges because their unit cell size scales with wavelength; and (
ii
) Metamaterials overcome this size dependence because they rely on local resonances, but the resulting band gaps are very narrow. Here, we introduce a class of materials, elastic metastructures, that exploit resonating elements to broaden and lower Bragg gaps while reducing the mass of the system. This approach to band-gap engineering can be used for low-frequency vibration absorption and wave guiding across length scales.
The depiction of size and shape in gestures accompanying object descriptions in Anyi (Côte d’Ivoire) and in Dutch (The Netherlands)
Authors: Nyst Victoria
Published: July 2016

A comparison of size gestures made during object descriptions by Anyi speakers from the Ivory Coast and Dutch speakers in the Netherlands reveals considerable formational differences. Firstly, whereas all Anyi speakers make use of body parts to depict size and shape, none of the Dutch speakers do. Secondly, Dutch gestures outlining a size and shape in space are more varied than their Anyi counterparts in the number and distribution of the different handshapes, orientations, and movements. In addition, we report comparisons among Anyi speakers in which body parts are used as a way of showing the size of objects with signs for sizes employed in the sign language used by deaf and hearing signers in Adamorobe, a village community in Ghana that is linguistically and culturally related to the Anyi communities in Côte d’Ivoire. This comparison reveals significant similarities as well as differences, suggesting how co-speech gestures may have been adapted for use in this sign language.
Intensifier actions in Israeli Sign Language (ISL) discourse
Authors: Fuks Orit
Published: July 2016

The study describes certain structural modifications employed on the citation forms of ISL during signing for intensification purposes. In Signed Languages, citation forms are considered relatively immune to modifications. Nine signers signed several scenarios describing some intense quality. The signers used conventional adverbs existing in ISL for intensification purposes. Yet, they also employed idiosyncratic modifications on the formational components of adjectives simultaneously to form realization. These optional modifications enriched the messages conveyed merely by the conventional forms. They show that signers can incorporate gradient modes of expressions directly into the production of the lexical items to communicate more diverse and explicit messages in context. Using a comparative semiotic approach allowed us to describe the synergetic cooperation manifested at the stage of utterance construction between formational elements which were more suited to convey gradient and analog meanings in context and those that were less suited and thus not modified.
Communication without language
Authors: Cissewski Julia , Boesch Christophe
Published: July 2016

Great apes do not possess language or any comparable system of symbolic communication. Yet they communicate intentionally and possess cognitive competencies like categorization and decontextualization. These provide the basis for mental concepts and the meaning side of linguistic symbols. The arbitrarily linked and conventionalized forms for expressing these meanings, however, seem to be largely missing. We propose two strategies that may allow great apes to communicate a wide array of meanings without creating numerous arbitrarily linked forms. First, we suggest the existence of ‘population-specific semantic shifts’: within a population a communicative signal’s meaning is modified without changing its form, resulting in a new ‘vocabulary item’. Second, we propose that great apes, in addition to possessing sophisticated inferential abilities, intentionally display behaviors without overt communicative intent to provide eavesdropping conspecifics with ‘natural meaning’ (in the Gricean sense) and thus to influence their behavior.
Visible movements of the orofacial area
Authors: Wacewicz Sławomir , Żywiczyński Przemysław , Orzechowski Sylwester
Published: July 2016

The age-old debate between the proponents of the gesture-first and speech-first positions has returned to occupy a central place in current language evolution theorizing. The gestural scenarios, suffering from the problem known as “modality transition” (why a gestural system would have changed into a predominantly spoken system), frequently appeal to the gestures of the orofacial area as a platform for this putative transition. Here, we review currently available evidence on the significance of the orofacial area in language evolution. While our review offers some support for orofacial movements as an evolutionary “bridge” between manual gesture and speech, we see the evidence as far more consistent with a multimodal approach. We also suggest that, more generally, the “gestural versus spoken” formulation is limiting and would be better expressed in terms of the relative input and interplay of the visual and vocal-auditory sensory modalities.
Biotechnological approaches to growing green energy from
Jatropha curcas
: challenges due to the undomesticated status of the species.
Authors: Maghuly F. , Haas B. , Laimer M.
Published: July 2016

Jatropha curcas
is one of the major tropical biofuel crops in the Euphorbiaceae family. The species is an attractive candidate for biofuel production at industrial scale, for medicinal purposes and for halting desertification due to its adaptability to diverse environmental conditions. However, major obstacles to these endeavours include limited genetic diversity of the species, limited information about its distribution and domestication, lack of experience with crop performance and agronomy, environmental effects, few and disconnected crop improvement programmes and toxin production, which slow down the realization of the full potential of
J. curcas
. This review presents how
Jatropha
was selected or domesticated by the Mesoamerican civilizations in tropical regions, how it arrived to the subtropical, humid and dry regions of Africa and Asia, and when its genetic improvement was started following different breeding goals. Further, the recent biotechnological advances and new breeding technologies - which improve performance and increase genetic diversity - are highlighted. Newly emerging strategies and technologies and their potential to significantly increase crop production are discussed.