bluuebunny/crossref_metadata_2025 huggingface dataset:
Remarkably stable amorphous metal oxide grown on Zr-Cu-Be metallic glass
Authors: Lim Ka Ram , Kim Chang Eun , Yun Young Su , Kim Won Tae , Soon Aloysius , Kim Do Hyang
Published: December 2015

In the present study, we investigated the role of an aliovalent dopant upon stabilizing the amorphous oxide film. We added beryllium into the Zr50Cu50 metallic glass system and found that the amorphous oxide layer of Be-rich phase can be stabilized even at elevated temperature above Tg of the glass matrix. The thermal stability of the amorphous oxide layer is substantially enhanced due to Be addition. As confirmed by high-temperature cross-section HR-TEM, fully disordered Be-added amorphous layer is observed, while the rapid crystallization is observed without Be. To understand the role of Be, we employed ab-initio molecular dynamics to compare the mobility of ions with/without Be dopant and propose a disordered model where Be dopant occupies Zr vacancy and induces structural disorder to the amorphous phase. We find that the oxygen mobility is slightly suppressed due to Be dopant and Be mobility is unexpectedly lower than that of oxygen, which we attribute to the aliovalent nature of Be dopant whose diffusion always accompany multiple counter-diffusion of other ions. Here, we explain the origin of superior thermal stability of amorphous oxide film in terms of enhanced structural disorder and suppressed ionic mobility due to the aliovalent dopant.
PEGylated silica-enzyme nanoconjugates: a new frontier in large scale separation of α-amylase
Authors: Mohsen Dehnavi Seyed , Pazuki Gholamreza , Vossoughi Manouchehr
Published: December 2015

High resolution is nearly lost at the expense of throughput in most conventional bioseparation methods. Nanoparticles, due to their high surface to volume ratio, are attractiveenzyme carriers, which can boost the performance of extraction manifold. Here, wereport design and application ofa method highly capable of improving the partitioning of α-amylase in aqueous two-phase system of polymer and salt. Silica nanoparticle introduced to the system acts as a bridge that connects the enzyme and polymer. Theconjugated nanoparticles form the major part of the upper phase and thus significantly enhance the protein recovery. A thorough investigation was performed on the structure of the nanoconjugatesas well as analyzing the conformational structure of the enzyme after conjugationto explore anypossible denaturation.
Applications of gradient index metamaterials in waveguides
Authors: Fu Yangyang , Xu Yadong , Chen Huanyang
Published: December 2015

In this letter, we find that gradient index metamaterials (GIMs) could be utilized to manipulate wave propagation in waveguides. Through manipulating the conversion between propagating wave and surface wave, we can design some interesting applications in waveguides, such as controlling transmission effect, realizing bending waveguide and achieving waveguide splitting effect. These devices not only work for both transverse electric and magnetic polarized waves, but also function for a broadband of spectra. Numerical simulations are performed to verify our findings.
Ultrafast degradation of azo dyes catalyzed by cobalt-based metallic glass
Authors: Qin X. D. , Zhu Z. W. , Liu G. , Fu H. M. , Zhang H. W. , Wang A. M. , Li H. , Zhang H. F.
Published: December 2015

Reactivity and mass loss are considered mutually exclusive in conventional zero-valent metal (ZVM) technology to treat environmental contaminants. Here, we report the outstanding performance of Co-based metallic glass (MG) in degrading an aqueous solution of azo dye, thus eliminating this trade-off. Ball-milled Co-based MG powders completely degrade Acid Orange II at an ultrafast rate. The surface-area-normalized rate constant of Co-based MG powders was one order of magnitude higher than that of Co-based crystalline counterparts and three orders of magnitude higher than that of the widely studied Fe0 powders. The coordinatively unsaturated local structure in Co-based MG responds to the catalysis for degradation, resulting in very low mass loss. Wide applicability and good reusability were also present. Co-based MG is the most efficient material for azo dye degradation reported thus far and will promote the practical application of MGs as functional materials.
Anomalous Dynamics of a Lipid Recognition Protein on a Membrane Surface
Authors: Yamamoto Eiji , Kalli Antreas C. , Akimoto Takuma , Yasuoka Kenji , Sansom Mark S. P.
Published: December 2015

Pleckstrin homology (PH) domains are lipid-binding modules present in peripheral membrane proteins which interact with phosphatidyl-inositol phosphates (PIPs) in cell membranes. We use multiscale molecular dynamics simulations to characterize the localization and anomalous dynamics of the DAPP1 PH domain on the surface of a PIP-containing lipid bilayer. Both translational and rotational diffusion of the PH domain on the lipid membrane surface exhibit transient subdiffusion, with an exponent α ≈ 0.5 for times of less than 10 ns. In addition to a PIP3 molecule at the canonical binding site of the PH domain, we observe additional PIP molecules in contact with the protein. Fluctuations in the number of PIPs associated with the PH domain exhibit 1/f noise. We suggest that the anomalous diffusion and long-term correlated interaction of the PH domain with the membrane may contribute to an enhanced probability of encounter with target complexes on cell membrane surfaces.
Condensation and dissolution of nematic droplets in dispersions of colloidal rods with thermo–sensitive depletants
Authors: Modlińska Anna , Alsayed Ahmed M. , Gibaud Thomas
Published: December 2015

Nematic droplets are droplets composed of elongated molecules that tend to point in the same direction but do not have any positional order. Such droplets are well known to adopt a spindle shape called tactoid. How such droplets condensate or melt and how the orientational symmetry is broken remains however unclear. Here we use a colloidal system composed of filamentous viruses as model rod–like colloids and pnipam microgel particles to induce thermo–sensitive depletion attraction between the rods. Microscopy experiments coupled to particle tracking reveal that the condensation of a nematic droplet is preceded by the formation of a new phase, an isotropic droplet. As the viruses constitute an excellent experimental realization of hard rods, it follows that the phenomenology we describe should be relevant to diverse micro- and nano-sized rods that interact through excluded volume interactions. This transition between isotropic and nematic droplets provides a new and reversible pathway to break the symmetry and order colloidal rods within a droplet with an external stimulus and could constitute a benchmark experiment for a variety of technologies relying on reconfigurable control of rods.
Amide-assisted intramolecular [3+2] annulation of cyclopropane ring-opening: a facile and diastereoselective access to the tricyclic core of (±)-scandine
Authors: Xiao Jun-An , Xia Peng-Ju , Zhang Xing-Yu , Chen Xiao-Qing , Ou Guang-Chuan , Yang Hua
Published: December 2015

The amide-linked intramolecular [3+2] annulation of cyclopropane ring-opening has been developed to rapidly and diastereoselectively install the tricyclic dihydroquinolinone core of (±)-scandine.
Nickel-catalyzed synthesis of (E)-olefins from benzylic alcohol derivatives and arylacetonitriles via C–O activation
Authors: Xiao Jing , Yang Jia , Chen Tieqiao , Han Li-Biao
Published: December 2015

An efficient Ni-catalyzed synthesis of (E)-olefins using the readily available benzylic alcohol derivatives and arylacetonitriles is described. This transformation should proceed via a tandem process involving nickel-catalyzed cross coupling via C–O activation and subsequent stereoselective E2 elimination.
Recent development of carbon electrode materials and their bioanalytical and environmental applications
Authors: Zhang Wei , Zhu Shuyun , Luque Rafael , Han Shuang , Hu Lianzhe , Xu Guobao
Published: December 2015

New synthetic approaches, materials, properties, electroanalytical applications and perspectives of carbon materials are presented.
Highly efficient nonprecious metal catalysts towards oxygen reduction reaction based on three-dimensional porous carbon nanostructures
Authors: Zhu Chengzhou , Li He , Fu Shaofang , Du Dan , Lin Yuehe
Published: December 2015

This Tutorial Review focuses on the rational design and synthesis of 3D porous carbon nanostructure-based nonprecious metal catalysts and exploration of them in a highly efficient oxygen reduction reaction.
Complex organic corona formation on carbon nanotubes reduces microbial toxicity by suppressing reactive oxygen species production
Authors: Lawrence J. R. , Swerhone G. D. W. , Dynes J. J. , Hitchcock A. P. , Korber D. R.
Published: December 2015

Interactions of carbon nanotubes with organic matter and microbes creates a corona which reduces toxicity.
Infrared imaging of small molecules in living cells: from in vitro metabolic analysis to cytopathology
Authors: Quaroni Luca , Zlateva Theodora , Wehbe Katia , Cinque Gianfelice
Published: December 2015

A major topic in InfraRed (IR) spectroscopic studies of living cells is the complexity of the vibrational spectra, involving hundreds of overlapping absorption bands from all the cellular components present at detectable concentrations. We focus on the relative contribution of both small-molecule metabolites and macromolecules, while defining the spectroscopic properties of cells and tissue in the middle IR (midIR) region. As a consequence, we show the limitations of current interpretative schemes that rely on a small number of macromolecules for IR band assignment. The discussion is framed specifically around the glycolytic metabolism of cancer cells because of the potential pharmacological applications. Several metabolites involved in glycolysis by A549 lung cancer cells can be identified by this approach, which we refer to as Correlated Cellular Spectro-Microscopy (CSM). It is noteworthy that the rate of formation or consumption of specific molecules could be quantitatively assessed by this approach. We now extend this analysis to the two-dimensional case by performing IR imaging on single cells and cell clusters, detecting variations of metabolite concentration in time and space across the sample. The molecular detail obtained from this analysis allows its use in evaluating the pharmacological effect of inhibitors of glycolytic enzymes with potential consequences for in vitro drug testing. Finally we highlight the implications of the spectral contribution from cellular metabolites on applications in IR spectral cytopathology (SCP).
Ammonia decomposition catalysis using lithium–calcium imide
Authors: Makepeace Joshua W. , Hunter Hazel M. A. , Wood Thomas J. , Smith Ronald I. , Murray Claire A. , David William I. F.
Published: December 2015

Lithium–calcium imide is explored as a catalyst for the decomposition of ammonia. It shows the highest ammonia decomposition activity yet reported for a pure light metal amide or imide, comparable to lithium imide–amide at high temperature, with superior conversion observed at lower temperatures. Importantly, the post-reaction mass recovery of lithium–calcium imide is almost complete, indicating that it may be easier to contain than the other amide–imide catalysts reported to date. The basis of this improved recovery is that the catalyst is, at least partially, solid across the temperature range studied under ammonia flow. However, lithium–calcium imide itself is only stable at low and high temperatures under ammonia, with in situ powder diffraction showing the decomposition of the catalyst to lithium amide–imide and calcium imide at intermediate temperatures of 200–460 °C.
Determination of 22 trace elements in high-purity copper including Se and Te by ETV-ICP OES using SF6, NF3, CF4and H2as chemical modifiers
Authors: Hassler J. , Matschat R. , Richter S. , Barth P. , Detcheva A. K. , Waarlo H.-J.
Published: December 2015

Experiments with SF6, NF3, CF4and H2as new modifier gases for the matrix studied were performed. Pre-treatment steps of sub-samples (e.g., roasting) can now be omitted; the scope of application was enlarged to Au and hydride forming elements (such as Se, Te).
An exothermic chip for point-of-care testing using a forehead thermometer as a readout
Authors: Gao Bingbing , Liu Hong , Gu Zhongze
Published: December 2015

We report an exothermic chip for quantitative point-of-care testing using a forehead thermometer as a readout.
Facile formulation of starch–silver-nanoparticle encapsulated dichlorvos and chlorpyrifos for enhanced insecticide delivery
Authors: Ihegwuagu Nnemeka Edith , Sha'Ato Rufus , Tor-Anyiin Terrumun Amom , Nnamonu Lami Angela , Buekes Philip , Sone Bertrand , Maaza Malik
Published: December 2015

The facile formulation of starch–silver nanoparticle encapsulated dichlorvos and chlorpyrifos, respectively, was explored in this study with the view to develop a safer and more economical insecticide delivery system.
Investigation of the surface passivation mechanism through an Ag-doped Al-rich film using a solution process
Authors: Khan Firoz , Baek Seong-Ho , Kim Jae Hyun
Published: December 2015

A cost effective, hydrogen annealed Ag-doped Al-rich zinc oxide film for excellent passivation of silicon surfaces via a solution process.
Dual-enhanced photothermal conversion properties of reduced graphene oxide-coated gold superparticles for light-triggered acoustic and thermal theranostics
Authors: Lin Li-Sen , Yang Xiangyu , Niu Gang , Song Jibin , Yang Huang-Hao , Chen Xiaoyuan
Published: December 2015

A facile method was developed for the fabrication of reduced graphene oxide-coated gold superparticles with dual-enhanced photothermal conversion properties.
Co-delivery of doxorubicin and arsenite with reduction and pH dual-sensitive vesicle for synergistic cancer therapy
Authors: Zhang Lu , Xiao Hong , Li Jingguo , Cheng Du , Shuai Xintao
Published: December 2015

A reduction and pH dual-sensitive nanovesicle co-delivers doxorubicin and arsenite for synergistic anticancer therapy.
Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future
Authors: Kärkäs Markus D. , Matsuura Bryan S. , Monos Timothy M. , Magallanes Gabriel , Stephenson Corey R. J.
Published: December 2015

Recent advances in transition-metal catalyzed depolymerization of lignin to value-added products are discussed in this review.
Titania modification with a ruthenium(ii) complex and gold nanoparticles for photocatalytic degradation of organic compounds
Authors: Zheng Shuaizhi , Wei Zhishun , Yoshiiri Kenta , Braumüller Markus , Ohtani Bunsho , Rau Sven , Kowalska Ewa
Published: December 2015

Titania of fine anatase nanoparticles (ST01) was modified successively with two components, i.e., a ruthenium(ii) complex with phosphonic anchoring groups [Ru(bpy)2(4,4′-(CH2PO3H2)2bpy)]2+ bpy = 2,2′-bipyridine (RuIICP) and gold nanoparticles (Au). Various compositions of two titania modifiers were investigated, i.e., Au, Au + RuIICP, Au + 0.5RuIICP, RuIICP, 0.5RuIICP and 0.25RuIICP, where Au and RuIICP correspond to 0.81 mol% and 0.34 mol% (with respect to titania), respectively. In the case of hybrid photocatalysts, the sequence of modification (ruthenium(ii) complex adsorption or gold deposition) was investigated to check its influence on the resultant properties and thus photocatalytic performance. Diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM) were applied to characterize the structural properties of the prepared photocatalysts, which confirmed the successful introduction of modifiers of the ruthenium(ii) complex and/or gold NPs. Different distributions of gold particle sizes and chemical compositions were obtained for the hybrid photocatalysts prepared with an opposite sequence. It was found that photocatalytic activities depended on the range of used irradiation (UV/vis or vis) and the kind of modifier in different ways. Gold NPs improved the photocatalytic activities, while RuIICP inhibited the reactions under UV/vis irradiation, i.e., methanol dehydrogenation and acetic acid degradation. Oppositely, RuIICP greatly enhanced the photocatalytic activities for 2-propanol oxidation under visible light irradiation.
Incorporation of SnO2 nanoparticles in PMMA for performance enhancement of a transparent organic resistive memory device
Authors: Sarkar Pranab Kumar , Bhattacharjee Snigdha , Prajapat Manoj , Roy Asim
Published: December 2015

Various sizes of SnO2 NPs have been successfully synthesized and embedded into the insulating PMMA layer sandwiched between ITO and Al electrodes.
CdS sensitized TiO2 photoanodes for quantum dot-sensitized solar cells by hydrothermal assisted chemical bath deposition and post-annealing treatment
Authors: Zhang Quanxin , Cao Jiamei , Li Hongguang
Published: December 2015

A hydrothermal assisted chemical bath deposition method was adopted to directly deposit CdS quantum dots on TiO2 photoanodes in QDSCs for the first time. An efficiency of 1.78% is achieved with appropriate post-annealing treatment.
Fabrication of earth-abundant Cu2ZnSn(S,Se)4 light absorbers by a sol–gel and selenization route for thin film solar cells
Authors: Zeng Fang Qin , Lai Yan Qing , Han Zi Li , Ng Boon K. , Zhang Zhi An , Zhang Hong Liang , Jiang Liang Xing , Liu Fang Yang
Published: December 2015

A CZTSSe thin film solar cell was fabricated by a sol–gel method with an efficiency of 8.08%.
Colourimetric assay for β-estradiol based on the peroxidase-like activity of Fe3O4@mSiO2@HP-β-CD nanoparticles
Authors: Wei Shoulian , Li Jianwen , Liu Yong
Published: December 2015

Schematic illustration of the colourimetric detection of β-E2 by using a Fe3O4@mSiO2@HP-β-CD nanoparticle catalyzed color reaction.
Development of a julolidine-based interfacial modifier for efficient inverted polymer solar cells
Authors: Choi Eun Young , Nam So Youn , Song Chang Eun , Kong Ki-jeong , Lee Changjin , Jung In Hwan , Yoon Sung Cheol
Published: December 2015

We demonstrate the julolidine moiety is an excellent electron donating building block for developing interfacial modifiers to improve the ZnO surface properties in inverted polymer solar cells.
Properties and sodium salicylate induced aggregation behavior of a tail-branched cationic surfactant with a hydroxyl-containing hydrophilic head
Authors: Zhang Yongjie , Li Yunling , Song Yongbo , Li Jun
Published: December 2015

This paper introduced a cationic amphiphile with remarkable surface activity, whose aggregation behavior could be modulated by salt addition.
Copper(ii) quinolinonato-7-carboxamido complexes as potent antitumor agents with broad spectra and selective effects
Authors: Křikavová Radka , Vančo Ján , Trávníček Zdeněk , Buchtík Roman , Dvořák Zdeněk
Published: December 2015

[Cu(quix)(phen)]NO3·yH2O (quix = 2-(4-amino-3,5-dichlorophenyl)-3-hydroxy-4(1H)-quinolinone-7-carboxamides) showed potent cytotoxicity against human cancer cells, lower toxicity on non-malignant cells, and ability to interact with biomolecules.
The degradation of mechanical properties in polymer nano-composites exposed to liquid media – a review
Authors: Saharudin Mohd Shahneel , Atif Rasheed , Shyha Islam , Inam Fawad
Published: December 2015

The advancement of polymer nano-composites has been motivated by the need for materials with a specific combination of mechanical properties beyond those achieved from only one material.
Iodine-mediated synthesis of benzopyridothiazines via tandem C–H thiolation and amination
Authors: Wei Liang , Xu Li , Tang Ri-Yuan
Published: December 2015

Tandem C–H thiolation/amination for benzopyridothiazines.
Preparation and characterization of an expanded perlite/paraffin/graphene oxide composite with enhanced thermal conductivity and leakage-bearing properties
Authors: Lu Zeyu , Hou Dongshuai , Xu Biwan , Li Zongjin
Published: December 2015

A novel phase change material (PCMs) of expanded perlite/paraffin/graphene oxide (EP/PA/GO) with enhanced thermal conductivity and leakage-bearing properties was fabricated by depositing GO films on the surface of the EP/PA composite.
Surface PEGylation on PLA membranes via micro-swelling and crosslinking for improved biocompatibility/hemocompatibility
Authors: Yu Xuemin , Xiong Zhu , Li Jinglong , Wu Ziyang , Wang Yunze , Liu Fu
Published: December 2015

A feasible and efficient strategy was developed to enable persistent PEGylation on a PLA membrane surface via micro-swelling and subsequent UV-initiated crosslinking of poly(ethylene glycol) diacrylate.
Microbial mediated synthesis, characterization, antibacterial and synergistic effect of gold nanoparticles using Klebsiella pneumoniae (MTCC-4030)
Authors: Prema P. , Iniya P. A. , Immanuel G.
Published: December 2015

Herein, the microbial mediated synthesis of gold nanoparticles (GNPs) was achievedviaan easy biological protocol usingKlebsiella pneumoniae(MTCC-4030).
Enhanced encapsulation of superparamagnetic Fe3O4 in acidic core-containing micelles for magnetic resonance imaging
Authors: Biswas Depannita , Li Puzhen , Liu Dapeng , Oh Jung Kwon
Published: December 2015

Block copolymer-based magnetic nanoassembled structures with acidic cores exhibiting enhanced loading level of superparamagnetic iron oxide nanoparticles, thus having great potential for theranostics based on MRI.
Upgrading of bio-oil and subsequent co-processing under FCC conditions for fuel production
Authors: Huynh Thuan Minh , Armbruster Udo , Atia Hanan , Bentrup Ursula , Phan Binh Minh Quoc , Eckelt Reinhard , Nguyen Luong Huu , Nguyen Duc Anh , Martin Andreas
Published: December 2015

NiCo/ZSM-5 revealed a bio-oil HDO deoxygenation degree of 39% and increase of the heating value of product oil to 33.3 MJ kg−1.
Aminofluorination: transition-metal-free N–F bond insertion into diazocarbonyl compounds
Authors: Chen Gui , Song Jinshuai , Yu Yinghua , Luo Xuesong , Li Chunsen , Huang Xueliang
Published: December 2015

Gem-aminofluorination of diazocarbonyl compounds has been achieved for the first time.
Rational design of a nested pore structure sulfur host for fast Li/S batteries with a long cycle life
Authors: Wang Meiri , Zhang Hongzhang , Zhou Wei , Yang Xiaofei , Li Xianfeng , Zhang Huamin
Published: December 2015

Quad-modal nested pore structure carbon with ordered hierarchical pores for fast Li/S batteries with a long cycle life.
A one-step electrodeposition of homogeneous and vertically aligned nanotubes with parahydrophobic properties (high water adhesion)
Authors: Darmanin Thierry , Guittard Frédéric
Published: December 2015

Nanotubes of various dimensions displaying parahydrophobic properties are obtained by a one-step electropolymerization of naphtho[2,3-b]thieno[3,4-e][1,4]dioxine (NaphDOT) without surfactants or hard templates.
Directing immunomodulation using biomaterials for endogenous regeneration
Authors: Yu Yang , Wu Rui-Xin , Yin Yuan , Chen Fa-Ming
Published: December 2015

Biomaterials recreated an artificial biochemical and mechanical niche at the implanted site that coaxed polarized macrophages to display a spectrum of functional phenotypes that are required for stem cell homing and endogenous regeneration.
Monodisperse macromolecules based on benzodithiophene and diketopyrrolopyrrole with strong NIR absorption and high mobility
Authors: Wang Jiayu , Shi Keli , Suo Yue , Lin Yuze , Yu Gui , Zhan Xiaowei
Published: December 2015

A series of monodisperse macromolecules based on benzodithiophene and diketopyrrolopyrrole were designed, theoretically calculated, synthesized and compared, and they exhibited strong NIR absorption and high mobility.
Operational experiences with inertial response provided by type 4 wind turbines
Authors: Fischer Markus , Engelken Soenke , Mihov Nikolay , Mendonca Angelo
Published: December 2015

The need for inertial response provided by wind turbines (WTs) has been discussed in the industry for more than five years now. Yet, as of today only very few grid codes include specific requirements. Hence, the number of wind farms in commercial operation using such frequency control features is low, and knowledge of the real capabilities and limitations of inertial response from WTs is limited. The objective of this article was to summarise and to assess two years of operational experience with inertial response provided by type 4 WTs installed in a 138 MW wind farm in the Canadian province of Québec. In order to put the topic into context, existing and anticipated future grid code requirements in respect to inertial response as well as related performance criteria were summarised. Data from high‐frequency measurement devices recorded at various operating conditions and grid situations was downloaded and processed. The actual performance was compared with the expected characteristics for each of the measurements, which allowed identifying areas for further development. Results of dynamic simulations demonstrated that the methodology and the models used for frequency control studies need to be improved.
A facility for X-ray diffraction in magnetic fields up to 25 T and temperatures between 15 and 295 K
Authors: Wang S. , Kovalev A. E. , Suslov A. V. , Siegrist T.
Published: December 2015

A facility for X-ray diffraction has been developed at the National High Magnetic Field Laboratory. It brings diffraction capability to the 25 T Florida split coil magnet and implements temperature control in a range of 15–295 K using a cold finger helium cryostat. This instrument represents an alternative to pulsed magnetic field systems, and it exceeds the static magnetic fields currently available at synchrotron facilities. Magnetic field compatibility of an X-ray source and detectors with the sizable magnetic fringe fields emanating from the magnet constrained the design of the diffractometer.
Temperature-dependent magnetization reversal process and coercivity mechanism in Nd-Fe-B hot-deformed magnets
Authors: Okamoto Satoshi , Goto Ryota , Kikuchi Nobuaki , Kitakami Osamu , Akiya Takahiro , Sepehri-Amin Hossein , Ohkubo Tadakatsu , Hono Kazuhiro , Hioki Keiko , Hattori Atsushi
Published: December 2015

Low coercivity and its large temperature dependence of a Nd2Fe14B magnet with respect to its magnetic anisotropy field have been addressed as the coercivity problem. To elucidate the physical origin of this problem, we have investigated the temperature dependence of the magnetization reversal behavior in the Nd-Fe-B hot-deformed magnet. Based on the analysis of the energy barrier evaluated from magnetic viscosity measurements, the coercivity problem is discussed in terms of the following three aspects: magnetization reversal process, intrinsic coercivity without thermal demagnetization effect, and energy barrier height. The analyses lead us to conclude that domain wall pinning is dominant in the magnetization reversal in the Nd-Fe-B hot-deformed magnet. The temperature dependences of the intrinsic coercivity and the energy barrier height are explained by the grain boundary model with an intermediate layer. These analyses would be utilized to discuss the detailed structure and magnetic properties of the grain boundary, which gives a new insight to overcome the coercivity problem.
In situ investigations of laser and thermally modified As2S3 nanolayers: Synchrotron radiation photoelectron spectroscopy and density functional theory calculations
Authors: Kondrat O. , Holomb R. , Popovich N. , Mitsa V. , Veres M. , Csik A. , Feher A. , Tsud N. , Vondráček M. , Matolín V. , Prince K. C.
Published: December 2015

As-deposited, annealed, and in situ As2S3 nanolayers, illuminated by blue (405 nm) and red (650 nm) laser light, were studied using synchrotron radiation photoelectron spectroscopy and DFT electronic structure calculations. Changes in composition and local atomic coordination occurring in the irradiated region of As2S3 films were monitored by analysis of As 3d and S 2p core levels. These studies show that both the thermal treatment and the red laser illumination of As2S3 nanolayers decrease the concentration of homopolar (As-As and S-S) bonds. From the other hand, an increasing concentration of As-rich structural units (s.u.) with a homopolar As-As bond was observed under in situ blue laser illumination of As2S3 nanolayers. Molecular orbital energies were calculated for different As- and S-centered s.u. and used for the interpretation of the core levels and valence band spectra. The surface local structure of the As2S3 nanolayers and its photoinduced transformation are discussed in detail.
Generation of arbitrary vector beams with liquid crystal polarization converters and vector-photoaligned q-plates
Authors: Chen Peng , Ji Wei , Wei Bing-Yan , Hu Wei , Chigrinov Vladimir , Lu Yan-Qing
Published: December 2015

Arbitrary vector beams (VBs) are realized by the designed polarization converters and corresponding vector-photoaligned q-plates. The polarization converter is a specific twisted nematic cell with one substrate homogeneously aligned and the other space-variantly aligned. By combining a polarization-sensitive alignment agent with a dynamic micro-lithography system, various categories of liquid crystal polarization converters are demonstrated. Besides, traditional radially/azimuthally polarized light, high-order and multi-ringed VBs, and a VB array with different orders are generated. The obtained converters are further utilized as polarization masks to implement vector-photoaligning. The technique facilitates both the volume duplication of these converters and the generation of another promising optical element, the q-plate, which is suitable for the generation of VBs for coherent lasers. The combination of proposed polarization converters and correspondingly fabricated q-plates would drastically enhance the capability of polarization control and may bring more possibilities for the design of photonic devices.
High thermal stable and fast switching Ni-Ge-Te alloy for phase change memory applications
Authors: Cao Liangliang , Wu Liangcai , Zhu Wenqing , Ji Xinglong , Zheng Yonghui , Song Zhitang , Rao Feng , Song Sannian , Ma Zhongyuan , Xu Ling
Published: December 2015

Ni-Ge-Te phase change material is proposed and investigated for phase change memory (PCM) applications. With Ni addition, the crystallization temperature, the data retention ability, and the crystallization speed are remarkably improved. The Ni-Ge-Te material has a high crystallization temperature (250 °C) and good data retention ability (149 °C). A reversible switching between SET and RESET state can be achieved by an electrical pulse as short as 6 ns. Up to ∼3 × 104 SET/RESET cycles are obtained with a resistance ratio of about two orders of magnitude. All of these demonstrate that Ni-Ge-Te alloy is a promising material for high speed and high temperature PCM applications.
Controllable spiking patterns in long-wavelength vertical cavity surface emitting lasers for neuromorphic photonics systems
Authors: Hurtado Antonio , Javaloyes Julien
Published: December 2015

Multiple controllable spiking patterns are achieved in a 1310 nm Vertical-Cavity Surface Emitting Laser (VCSEL) in response to induced perturbations and for two different cases of polarized optical injection, namely, parallel and orthogonal. Furthermore, reproducible spiking responses are demonstrated experimentally at sub-nanosecond speed resolution and with a controlled number of spikes fired. This work opens therefore exciting research avenues for the use of VCSELs in ultrafast neuromorphic photonic systems for non-traditional computing applications, such as all-optical binary-to-spiking format conversion and spiking information encoding.
Highly sensitive microfluidic flow sensor based on aligned piezoelectric poly(vinylidene fluoride-trifluoroethylene) nanofibers
Authors: Zhang Lingling , Yu Xiaolei , You Sujian , Liu Huiqin , Zhang Cancan , Cai Bo , Xiao Liang , Liu Wei , Guo Shishang , Zhao Xingzhong
Published: December 2015

A microfluidic flow sensor based on aligned piezoelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] nanofibers has been developed. The flow sensor is able to linearly measure low flow rates ranging from 13 μl/h to 301 μl/h with a sensitivity of 0.36 mV per 1 μl/h, and the highest voltage difference of 120 mV at a flow rate of 451 μl/h. Moreover, the viscosity of the ethylene glycol aqueous solution ranging from 1 mPa·s to 16.1 mPa·s at 25 °C can be detected in dynamic flow with a stable output. These findings highlight the potential of piezoelectric P(VDF-TrFE) nanofibers in multiferroic applications.
The emission wavelength dependent photoluminescence lifetime of the N-doped graphene quantum dots
Authors: Deng Xingxia , Sun Jing , Yang Siwei , Shen Hao , Zhou Wei , Lu Jian , Ding Guqiao , Wang Zhongyang
Published: December 2015

Aromatic nitrogen doped graphene quantum dots were investigated by steady-state and time-resolved photoluminescence (PL) techniques. The PL lifetime was found to be dependent on the emission wavelength and coincident with the PL spectrum, which is different from most semiconductor quantum dots and fluorescent dyes. This result shows the synergy and competition between the quantum confinement effect and edge functional groups, which may have the potential to guide the synthesis and expand the applications of graphene quantum dots.
A miniaturized piezoelectric turbine with self-regulation for increased air speed range
Authors: Fu Hailing , Yeatman Eric M.
Published: December 2015

This paper presents the design and demonstration of a piezoelectric turbine with self-regulation for increased air speed range. The turbine's transduction is achieved by magnetic “plucking” of a piezoelectric beam by the passing rotor. The increased speed range is achieved by the self-regulating mechanism which can dynamically adjust the magnetic coupling between the magnets on the turbine rotor and the piezoelectric beam using a micro-spring. The spring is controlled passively by the centrifugal force of the magnet on the rotor. This mechanism automatically changes the relative position of the magnets at different rotational speeds, making the coupling weak at low airflow speeds and strong at high speeds. Hence, the device can start up with a low airflow speed, and the output power can be ensured when the airflow speed is high. A theoretical model was established to analyse the turbine's performance, advantages, and to optimize its design parameters. A prototype was fabricated and tested in a wind tunnel. The start-up airflow speed was 2.34 m/s, showing a 30% improvement against a harvester without the mechanism.
The Attentional Capacity of Visual Search under Flicker Conditions
Authors: Rensink R A
Published: December 2015

High-level allocation of attention is required for detecting changes in images under ‘flicker’ conditions, ie when an original and a modified image are repetitively alternated, with a blank field between each display (R A Rensink, J K O'Regan, J J Clark, 1995 Perception24 Supplement, 26). But how many items can attention ‘grab’ and compare during each display? To determine this capacity, search experiments were carried out under flicker conditions, with displays formed of arrays of rectangles. In half the trials, displays differed by the position of one of the rectangles; in the other half, displays remained the same. Subjects were asked to determine if a change was occurring between the two displays.

Performance was measured for several durations of displays and blank fields. In all cases, search showed a clear serial deployment of attention. Comparing the rate of this deployment against the rate of display alternation yielded the number of items compared at a time. Results indicate that, for display durations of less than 100 ms, average capacity is about 1.5 items. Capacity increases somewhat with longer display times, indicating that more items can be stored with increasing display time, or that more items are being grouped into each attentional ‘operand’.
Abrupt Transitions in the Perception of Illusory Contours Triggered by Specific Visual Stimuli
Authors: Rubin N , Grossetete A , Nakayama K , Shapley R
Published: December 2015

Two forms of learning have been identified in previous studies. Gradual improvement is observed for many perceptual tasks; it is often stimulus-specific and is consequently thought to involve synaptic modifications in early visual cortical areas. In contrast, sudden transitions, either cognitive (‘insight’) or perceptual (eg in the Dalmatian dog picture) are generally thought to occur more centrally.

Here we report that a sudden transition in the perception of illusory-contour stimuli can be triggered by specific visual stimuli, rather than by verbal instructions, leading to an abrupt improvement in psychophysical performance.

Subjects discriminated between two classes of Kanizsa-like shapes where the (illusory) edges were slightly curved into ‘thin’ or ‘fat’ figures (D L Ringach, R Shapley, 1993 Perception22 Supplement, 51). In the first (‘test’) block, only small amounts of curvature (1° – 3°) were given; subjects performed poorly in that block. In the second (‘training’) block, stimuli with larger curvature (4° – 6°) were added to the set. Performance for the 1° – 3° stimuli improved abruptly—often within seconds—compared to the first block: the pooled responses of eight naive subjects showed a marked jump, followed by maintained elevation, of the fraction-correct responses as a function of time. Good performance was retained in a third (re-test) block, with a stimulus set identical to that of the first block. Control experiments verified that the subjects understood the task from the beginning. Furthermore, the learned performance did not transfer to a different (smaller) retinal size. Thus the jump in performance is a perceptual, stimulus-specific phenomenon (rather than a cognitive one), although it exhibits characteristics of ‘insightful’ understanding.
Hierarchical Motion Organization in Random-Dot Configurations
Authors: Bertamini M , Proffitt D R
Published: December 2015

Motion fields differ in the degree to which they can serve as hierarchical frames of reference. To assess the strength of hierarchical motion organisation, we measured the ability of human observers to extract the motion of a target dot relative to a background of moving dots. The task was to discriminate circular from elliptical relative motions for the target dot (2AFC). Observers performed above chance for translational and divergence backgrounds, but were at chance level for rotational backgrounds. This finding, however, was based on random configurations of dots, where locations and trajectories were unrelated. When spatial constraints were introduced, observers used a different strategy and performed above chance also for rotational backgrounds. Both the effect of motion transformations and the effect of spatial information can be understood if we assume that the task is to find the most likely mechanical description of an object in a three-dimensional environment.
What are the Mechanisms of Rivalrous First-Order and Second-Order Motions?
Authors: Gellatly A , Blurton A
Published: December 2015

There have been many reports in the visual motion literature describing how patterns of contrast reversal in bar stimuli may yield rivalrous motions in opposing directions. One of these, usually termed first-order motion, is generally explained in terms of ‘short range’ matching of same polarity edges or of standard motion analysis of the distribution of energy in the Fourier transform of the stimulus. The opposite, second-order, motion is usually explained in terms either of ‘long range’ matching of whole forms/features or of luminance signal rectification followed by standard motion analysis. It is known that the mechanisms underlying the two motions show differential sensitivity to manipulations of spatial frequency and eccentricity (Mather, Cavanagh, and Anstis, 1985 Perception14 163 – 166; Chubb and Sperling, 1989 Proceedings of the National Academy of Sciences of the USA86 2985 – 2989), and this paper reports a number of studies intended to further specify them in terms of their sensitivities and the interactions between them. The experiments employ mainly stimulus sequences in which luminance changes are unaccompanied by displacement of forms/features, and are designed to investigate the effects of manipulations involving the spacing of luminance events, modulations of directional power, camouflage, and attention. The results obtained raise questions about how the underlying mechanisms are best to be characterised. We are greatly indebted to Professor Ted Evans for technical guidance and assistance.
Mislocalisation of Chromatic and Achromatic Stimuli during Saccadic Eye Movements
Authors: Sato M , Uchikawa K
Published: December 2015

It is well known that a brief flash of a small stationary target presented during saccades appears to be shifted from the actual position. The perceptual location of a visual target should be determined by the retinal information and the eye position signal. This mislocalisation seems to indicate that the change of the eye position signal is more sluggish than the actual eye movements. Delay of transmission of the retinal information may be a factor of mislocalisation. Here, we measured the perceptual location of chromatic stimuli which had different temporal characteristics from achromatic stimuli.

The chromatic stimulus was a small red spot which replaced the green field for 10 ms. The green field subtended 5 deg × 24 deg and its luminance was 78.6 cd m−2. The luminance of the chromatic stimulus was adjusted to be the same as the green field by the minimum flicker method. The luminance of the achromatic stimulus was 234 cd m−2. Our results show that the chromatic and the achromatic stimuli presented at the beginning of saccades are mislocalised in the same direction as the saccades. We also found that the mislocalisation of the chromatic stimulus began slightly earlier than the achromatic stimulus. Also the chromatic stimulus presented during saccades was mislocalised in the opposite direction to the saccades whereas the achromatic stimulus was localised approximately at the actual position. These results suggest that the chromatic response is transmitted more slowly before saccades but faster during saccades than the achromatic response.
Control of Fixation Duration and Saccade Direction during Search
Authors: Hooge I T C , Erkelens C J
Published: December 2015

To investigate the interaction between saccade preparation and foveal analysis on multi-fixation search, we designed an experiment in which the result of the foveal analysis is relevant for programming the direction of the next saccade. We examined whether fixation duration is adjusted to the duration of the analysis process or not.

Subjects were asked to find a circle (diameter 2.1 deg) among 35 circles (gap size 0.3 deg, diameter 2.1 deg) that were placed on an invisible hexagonal grid (35 deg × 35 deg). Eye movements of the right eye were measured. The gaps of the circles indicated the direction in which the circle could be found. Subjects were instructed to make eye movements in the direction that was indicated by the gap of the fixated circle.

The proportion of eye movements made in the indicated directions ranged from 0.54 to 0.72 (0.25 is chance level). Thus direction information is indeed, but improperly, used for the programming of eye movements. Durations of fixations preceding eye movements made in non-indicated directions were smaller than durations of fixations preceding eye movements made in indicated directions. From these results we conclude that saccade preparation only uses the result of the analysis if it is available in time and that there is no direct control of fixation duration by a mechanism that monitors the analysis process.
Long-Term Changes in Colour Matching Functions after Exposure to Artificial Sunlight
Authors: Jordan G , Mollon J D
Published: December 2015

We have previously reported that relatively short exposures (30 to 60 min) to either sunlight or artificial sunlight are sufficient to shift Rayleigh matches for several hours in the protan direction (1995 Investigative Ophthalmology and Visual Science36 392). We have subsequently found that this effect cannot be explained by either an alteration in (i) the orientation of photoreceptors, ie no change was found in Stiles — Crawford I before and after adaptation (1995 Perception24 Supplement, 11), or by an alteration in (ii) the density of an observer's macular pigment. In order to distinguish more generally between a change in a pre-receptoral filter and a change in the spectral sensitivity of M or L cones, we are currently obtaining colour matching functions between 570 and 620 nm. Measurements are made before and after 45-min exposure to a white field receiving an illumination of about 40 000 lux from an arc lamp. The mixture primaries are 550 and 690 nm set at 100 td. The stimulus field subtends 2 deg. Matches are made by a temporal substitution method and two staircases are randomly interleaved. The standard wavelengths are randomised.
Spectral Bandwidths of Colour Detection Mechanisms
Authors: D'Zmura M , Knoblauch K
Published: December 2015

We measured the spectral properties of human colour detection mechanisms with a noise masking paradigm, using two new methods to overcome a potential artefact of previous procedures. Estimation of the spectral bandwidth mediating detection of binary colour signals (eg orange) would be misleadingly narrow if the observer changes strategy as a function of the colour of the masking noise (eg detecting the red component of an orange signal in yellow noise and vice versa). We induce observers to use a single detection mechanism throughout an experiment by adding either biaxial noise or sectored noise to the signal. With biaxial noise, one can eliminate detectability of an orange signal by a red-sensitive mechanism, for instance, by adding a steady source of noise along a red axis. We then measure the remaining (yellow) sensitivity by adding noise along a second, variable axis. Sectored noise consists of noise samples from sectors of variable width in the colour plane, centred around the signal axis. Detection with the use of off-axis mechanisms is a less optimal strategy with such noise. A decline in the potency of such noise with increasing sector width would suggest that the spectral bandwidth is narrow and nonlinear rather than broad and more nearly linear.
Colour Constancy in Goldfish—The Role of Surround Reflectance
Authors: Fritsch J , Neumeyer C
Published: December 2015

Simultaneous colour contrast as well as colour constancy have been shown quantitatively for the goldfish. In behavioural experiments we investigated colour constancy in goldfish for green and purple colours. Two fish were trained with food rewards to select one of ten test-fields in hues ranging, in small steps of saturation, from deep green, through grey, to deep purple. In the training situation the whole disk was illuminated by white light, whereas in the test situation it was changed to green and purple light, respectively.

The role of surround reflectance was investigated by presenting the test fields either on a black or on a white surround. With a black surround (low reflectance) in purple illumination the fish chose test fields that were more green than the training field indicating imperfect colour constancy. With a white surround (high reflectance), however, the fish chose testfields that were more purple. This ‘overcompensation’ indicates that a white surround induces a hue complementary to that of the illumination. A similar phenomenon is known as the Helson — Judd effect in human colour vision. For green illumination the phenomenon was similar. The effect could be decreased by reducing the white surround to small white annuli around the test fields. A decrease was also achieved by separating the white surround from the test fields by black annuli. Perfect colour constancy could thus be obtained with a certain size of a white surround as well as with a certain size of separation. We therefore assume that lateral interactions play an important role in colour constancy.