bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative end-group functionalization of PNIPAM from aqueous SET-LRP via in situ reduction of Cu(ii) with NaBH4
Authors: Gavrilov Mikhail , Jia Zhongfan , Percec Virgil , Monteiro Michael J.
Published: June 2016

Rapid in situ azidation and CuAAC ‘click’ reaction demonstrating very high chain-end functionality.
Synthesis of end-functionalized hydrogen-bonding poly(lactic acid)s and preferential stereocomplex crystallization of their enantiomeric blends
Authors: Bao Jianna , Chang Xiaohua , Shan Guorong , Bao Yongzhong , Pan Pengju
Published: June 2016

A novel UPy-functionalized alcohol was synthesized and used to initiate the solvent-free ROP of lactide to attain UPy-functionalized PLLA and PDLA. The crystallization rate and stereocomplexation ability of UPy-functionalized PLLA/PDLA blends were promoted.
Learning lessons from directed evolution of stereoselective enzymes
Authors: Li Guangyue , Reetz Manfred T.
Published: June 2016

With the advent of directed evolution of stereoselective enzymes almost 20 years ago and the rapid development of this exciting area of research, the traditional limitations of biocatalysts in organic chemistry have been eliminated.
Removal of heavy metal ions using functionalized graphene membranes: a molecular dynamics study
Authors: Kommu Anitha , Namsani Sadanandam , Singh Jayant K.
Published: June 2016

Comparison of water permeability and salt rejection of functionalized NPG sheets with existing technologies.
Sequential alcohol oxidation/putative homo Claisen–Tishchenko-type reaction to give esters: a key process in accessing novel biologically active lactone macrocycles
Authors: Viana Hugo , Carreiro Elisabete P. , Goth Albertino , Bacalhau Patrícia , Caldeira Ana Teresa , Martins Maria do Rosário , Burke Anthony Joseph
Published: June 2016

We report an efficient methodology for the direct oxidative esterification of primary alcohols to diether-esters using pyridinium chlorochromate (PCC).
Magnetic hyperthermia-induced drug release from ureasil-PEO-γ-Fe2O3 nanocomposites
Authors: Caetano B. L. , Guibert C. , Fini R. , Fresnais J. , Pulcinelli S. H. , Ménager C. , Santilli C. V.
Published: June 2016

A multifunctional hybrid material suitable for cancer therapy, combining stimuli-responsive properties for drug delivery and magnetic hyperthermia.
Nitrile N-oxides in programmable one-pot functionalization of multi-wall carbon nanotubes via 1,3-dipolar cycloaddition
Authors: Herman A. P. , Boncel S.
Published: June 2016

Multi-wall carbon nanotubes (MWCNTs) were one-pot functionalized with a series of nitrile N-oxides as 1,3-dipoles carrying diverse functional groups.
Synthesis of a cardanol-based phosphorus-containing polyurethane prepolymer and its application in phenolic foams
Authors: Bo Caiying , Wei Shikang , Hu Lihong , Jia Puyou , Liang Bingchuang , Zhou Jing , Zhou Yonghong
Published: June 2016

A cardanol-based P-containing polyurethane prepolymer (PPUP), a novel cardanol derivative, was synthesized.
Corrosion resistance of layer-by-layer assembled polyvinylpyrrolidone/polyacrylic acid and amorphous silica films on AZ31 magnesium alloys
Authors: Cui Lan-Yue , Zeng Rong-Chang , Li Shuo-Qi , Zhang Fen , Han En-Hou
Published: June 2016

A layer-by-layer (LbL)-assembled composite coating containing SiO2 and a biocompatible polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) multi-layer, designated as SiO2/(PVP/PAA)5, was prepared on AZ31 Mg alloy via dip-coating.
Conducting collagen-polypyrrole hybrid aerogels made from animal skin waste
Authors: Mekonnen Berhanu Telay , Ragothaman Murali , Kalirajan Cheirmadurai , Palanisamy Thanikaivelan
Published: June 2016

Animal skin wastes were converted into a biocompatible and conducting collagen-polypyrrole hybrid aerogels through in situ oxidative polymerization for a wide range of applications.
Multifunctional β-NaGdF4:Ln3+ (Ln = Yb, Er, Dy) nanoparticles with NIR to visible upconversion and high transverse relaxivity: a potential bimodal contrast agent for high-field MRI and optical imaging
Authors: Biju Silvanose , Harris Michael , Elst Luce Vander , Wolberg Marike , Kirschhock Christine , Parac-Vogt Tatjana N.
Published: June 2016

Developed nano β-NaGdF4 doped with Yb3+/Er3+ in the core and Yb3+/Dy3+ in the shell with favorable properties for combined magnetic resonance and optical imaging.
Synthesis of 2-oxophosphorindolines via the copper-catalyzed intramolecular aromatic C–H insertion of diazophosphonamidates
Authors: Huang Peipei , Xu Jiaxi
Published: June 2016

2-Ethoxy-2-oxophosphorindolines, benzo-γ-phospholactams, were synthesized efficiently with up to 97% yield through the copper-catalyzed intramolecular aromatic C–H insertion of diazophosphonamidates.
Hierarchical γ-BaB2O4 hollow microspheres: surfactant-assisted hydrothermal formation, phase conversion, optical properties and application as adsorbents
Authors: Chen Xiuping , Zhai Peiyan , Li Jie , Zhang Heng , Zhu Wancheng
Published: June 2016

A facile EDTA-2Na assisted hydrothermal route was developed for hierarchical γ-BaB2O4 hollow microspheres self-assembled from nanorods, with excellent thermostability and satisfactory performance for the removal of Pb2+ ions from mimic waste water.
Design of a hierarchically structured hybrid material via in situ assembly of a silica aerogel into a wood cellular structure
Authors: Sedighi Gilani M. , Zhao S. , Gaan S. , Koebel M. M. , Zimmermann T.
Published: June 2016

We present a route for incorporation of silica aerogel into wood cellular structure. Modification results in an improved dimensional stability and reduced water retention of the material, with lower thermal conductivity and total heat of combustion.
Design of a core–shell support to improve lipase features by immobilization
Authors: Manoel Evelin A. , Pinto Martina , dos Santos José C. S. , Tacias-Pascacio Veymar G. , Freire Denise M. G. , Pinto José Carlos , Fernandez-Lafuente Roberto
Published: June 2016

Different core–shell polymeric supports, exhbiting different featured, were produced and utilized in the immobilization and tuning of different lipases.
Fabrication of TiO2 nanosheets via Ti3+ doping and Ag3PO4 QD sensitization for highly efficient visible-light photocatalysis
Authors: Ma Lu , Han Hong , Pan Lun , Tahir Muhammad , Wang Li , Zhang Xiangwen , Zou Ji-Jun
Published: June 2016

Ag3PO4 QDs sensitized and Ti3+-doped TiO2 nanosheets were fabricated, and exhibit high charge-separation efficiency and high photocatalytic activity.
Adsorption of natural surface active compounds obtained from corn on human hair
Authors: Rincón-Fontán M. , Rodríguez-López L. , Vecino X. , Cruz J. M. , Moldes A. B.
Published: June 2016

In this work, an aqueous solution containing surface-active compounds, extracted from corn steep liquor (CSL), was added to human hair and its adsorption was studied by applying an incomplete factorial design.
Measuring the oxygen content of a single oil droplet
Authors: Feng Ann , Cheng Wei , Compton Richard G.
Published: June 2016

Using toluene droplets as a model for artificial oxygen carriers, the real-time measurement of attomole oxygen contents at the individual droplet level is reported for the first time.
Conducting polymer PPy nanowire-based triboelectric nanogenerator and its application for self-powered electrochemical cathodic protection
Authors: Cui Siwen , Zheng Youbin , Liang Jun , Wang Daoai
Published: June 2016

A novel triboelectric nanogenerator (TENG) was constructed with PPy nanowires (PPy NWs). By harvesting the energies in the ambient environment, the PPy NW-based TENG can act as a power supplier and provide extra electrons to the surface of the connected metals, forming effective impressed current cathodic protection.
Electrodeposited SiO2 film: a promising interlayer of a highly active Ti electrode for the oxygen evolution reaction
Authors: Wu Lian-Kui , Liu Xin-Yu , Hu Ji-Ming
Published: June 2016

A Ti-supported IrO2 or RuO2 coated electrode with significantly improved electrocatalytic activity for the OER was fabricated using a highly porous electrodeposited silica film as the interlayer. The highly porous morphology ensures its high activity. The “inter-locking” structure between the active oxide layer and SiO2 film prolongs its life.
Novel three-dimensional flower-like porous Al2O3 nanosheets anchoring hollow NiO nanoparticles for high-efficiency lithium ion batteries
Authors: Feng Yangyang , Zhang Huijuan , Fang Ling , Li Wenxiang , Wang Yu
Published: June 2016

We report novel 3D flower-like Al2O3 anchoring hollow NiO nanoparticles, which exhibits outstanding electrochemical performances in LIBs.
The effects of a series of carbon dots on fibrillation and cytotoxicity of human islet amyloid polypeptide
Authors: Wang Li , Zhu Shoujun , Lu Tong , Zhang Guangji , Xu Jia , Song Yubin , Li Yang , Wang Liping , Yang Bai , Li Fei
Published: June 2016

Carbon dots can change hIAPP aggregation kinetics and have a potential to reduce the cytotoxicity of the polypeptide.
Aqueous graphene oxide-dispersed carbon nanotubes as inks for the scalable production of all-carbon transparent conductive films
Authors: He Linxiang , Tjong Sie Chin
Published: June 2016

Aqueous graphene oxide-dispersed multi-walled carbon nanotubes were used as inks for the simple, fast, and industrially scalable fabrication of hybrid transparent conductive films by rod coating.
A naked eye colorimetric sensor for alcohol vapor discrimination and amplified spontaneous emission (ASE) from a highly fluorescent excited-state intramolecular proton transfer (ESIPT) molecule
Authors: Chen Ling , Yin Shao-Yun , Pan Mei , Wu Kai , Wang Hai-Ping , Fan Ya-Nan , Su Cheng-Yong
Published: June 2016

The special four-energy level of ESIPT molecule H2hpi2cf results in both naked-eye colorimetric discrimination of common alcohols and ASE photophysical properties.
Repairing sulfur vacancies in the MoS2 monolayer by using CO, NO and NO2 molecules
Authors: Ma Dongwei , Wang Qinggao , Li Tingxian , He Chaozheng , Ma Benyuan , Tang Yanan , Lu Zhansheng , Yang Zongxian
Published: June 2016

The repairing process of the MoS2 monolayer containing single S vacancies has been theoretically investigated by using CO, NO and NO2 molecules. The results show that repairing the S vacancy with CO, NO and NO2 molecules can be used to realize the C, N and O-doped MoS2 monolayers, respectively.
Hydrophobic coating over a CH3NH3PbI3 absorbing layer towards air stable perovskite solar cells
Authors: Xiong Hao , Rui Yichuan , Li Yaogang , Zhang Qinghong , Wang Hongzhi
Published: June 2016

Using a hydrophobic coating over a CH3NH3PbI3 absorbing layer can prevent perovskite solar cells from erosion due to humidity in the air.
Light-responsive hybrid material based on luminescent core–shell quantum dots and steroidal organogel
Authors: Schmidt L. C. , Edelsztein V. C. , Spagnuolo C. C. , Di Chenna P. H. , Galian R. E.
Published: June 2016

An integrated multifunctional QD–organogel hybrid with reversible photoswitchable luminescence properties is reported, combining the intrinsic properties of CdSe/ZnS core–shell QDs, a non-cholesteryl steroid organogel and a photochromic diarylethene.
Predictive hierarchical human augmented map generation for itinerary perception
Authors: Kaur B. , Bhattacharya J.
Published: June 2016

A new class of augmented map application is introduced which can provide detailed knowledge about any area, to a user. This brief particularly focuses on obtaining itinerary perception subject to different environmental conditions. This refers to extraction of traffic related information from an augmented map. The problem is modelled as a machine learning technique where the traffic distribution at different times (including same days, different days and different weather) are observed continuously using a service robot. This data is posed as a Gaussian process for post‐estimation. Our system consists of a vision sensor which will acquire the region of interest input, queried to a database of traffic density distributions, learned from the scenes at different points of time. The user interacting with the system will obtain an information pertaining to the region conditioned on environmental and timing events.
Screen‐printed mechanical switch based on stretchable PU‐foam film
Authors: Tolvanen J. , Hannu J. , Palosaari J. , Nelo M. , Jantunen H.
Published: June 2016

A screen‐printed mechanical switch based on an electrode structure on stretchable polyurethane (PU)‐foam film, Platilon U 4021, combined with a piezoelectric actuator, Smart Material MFC M‐4010‐P1, is proposed. The minimum actuation voltage of the prepared component is 300 V. The measured resistance was 2 Ω while closed and >0.5 TΩ when open. The electrode structure endured on average of up to 15.5 M cycles with movement ≥100 times greater than the ≤1 µm required for actuation. The results suggest that the switch could be advantageous for various e‐textile applications.
Breakdown voltage walkout resulting from hot‐carrier‐induced interface states in n‐type LDMOS transistors
Authors: Chen J.F. , Feng Y.‐S.
Published: June 2016

The mechanism of hot‐carrier‐induced drain breakdown voltage walkout in an n‐type lateral diffused MOS transistor is investigated. On the basis of the data of charge pumping measurement, hot‐carrier‐induced interface states created at the accumulation region is proposed to be responsible for the breakdown walkout. Further technology computer‐aided‐design simulations also support the before‐mentioned mechanism.
Estimating the frequency of trains approaching red signals: a case study for improving the understanding of SPAD risk
Authors: Zhao Yunshi , Stow Julian , Harrison Chris
Published: June 2016

This study describes a novel technique for estimating the frequency with which trains approach signals showing a red aspect. This knowledge is potentially important for understanding the likelihood of a signal being passed at danger (SPAD) at individual signals and also for normalisation of SPAD data, both locally and nationally, for trending and benchmarking. The industry currently uses estimates for the number of red aspect approaches based on driver surveys which are considered to have significant shortcomings. Data for this analysis is sourced from publicly available live feeds provided by Network Rail which give information on train movements and signal states. The development of the analysis model and supporting software are described and some sample results from case studies are presented. An initial study of seven signalling areas showed that approximately 3.3% of all signal approaches are to red signals. However, it also highlighted that there is a large variation in the red approach rates between signalling areas and between individual signals. SPAD risk assessment at individual signals may be significantly enhanced by the ability to estimate red approach rates for individual signals using the techniques described.
Path loss models with distance‐dependent weighted fitting and estimation of censored path loss data
Authors: Karttunen Aki , Gustafson Carl , Molisch Andreas F. , Wang Rui , Hur Sooyoung , Zhang Jianzhong , Park Jeongho
Published: June 2016

Path loss models are the most fundamental part of wireless propagation channel models. Path loss is typically modelled as a (single‐slope or multi‐slope) power‐law dependency on distance plus a log‐normally distributed shadowing attenuation. Determination of the parameters of this model is usually done by fitting the model to results from measurements or ray tracing. The authors show that the typical least‐square fitting to those data points is inherently biased to give the best fitting to the link distances that happen to have more evaluation points. A weighted fitting method is developed that emphasises the accuracy at the distance range that is consciously chosen by the user as most important for a system simulation. As a further important point that is typically not taken into account for path loss parameter extraction, the authors show that typically measurement data (but also ray tracing) is censored, i.e. path loss values above a certain threshold cannot be measured. The authors present examples of weighted fitting models, and models with and without the censored data, for 28 GHz channels in urban macrocells, and show that these effects have a significant impact on the extracted parameters and that the fitting accuracy can be improved with the presented methods.
Proposal for 4‐to‐2 optical encoder based on photonic crystals
Authors: Mehdizadeh Farhad , Soroosh Mohammad , Alipour‐Banaei Hamed
Published: June 2016

In this study, an all optical 4‐to‐2 encoder have been proposed which has four input and three output ports. The proposed structure can generate a 2‐bit binary code considering which input port is active. For realising the proposed structure first the authors proposed and designed a BUFFER and an OR gate. Then combined these basic gates to realise the proposed encoder. The maximum switching delay and footprint for the proposed structure are about 200 fs and 880 μm2, respectively.
Metal‐mesh based transparent electrodes using roll‐to‐sheet ultraviolet soft imprinting
Authors: Chuang Cheng‐Hsin , Chang Bo‐Hsiang , Chen Jian‐Ming , Lu Deng‐Maw
Published: June 2016

Transparent conductive electrodes (TCEs) possessing a combination of high optical transmission and good electrical conductivity find applications in numerous optoelectronic devices. A low cost fabrication of a fine metal‐mesh structure on rigid (glass) and flexible (polyethylene terephthalate – PET) substrates as a promising and feasible approach for fulfilling large size TCE requirements is proposed. A roll‐to‐sheet ultraviolet imprinting protocol to transfer microtrench structures using a flexible Polydimethylsiloxane stamp is utilised. The conductive silver ink is filled into the microtrench structures by controlling the processing parameters which include pressure, scraping angle and speed. The metal‐mesh based glass and PET substrates show a transmission of about 90%, while the electrical resistance is as low as 6 Ω/□. Thus, this method can be utilised as an economically viable alternative to doped indium oxide in TCE applications.
Atypical Evolutions of Idiopathic Focal Epilepsies in Childhood
Authors: Caraballo Roberto , Flesler Santiago , Fejerman Natalio
Published: June 2016

Clinical and electroencephalographic (EEG) features of the three well-defined idiopathic focal epilepsies in childhood (IFEC)—benign childhood epilepsy with centrotemporal spikes (BCECTS), Panayiotopoulos syndrome, and the Gastaut type of idiopathic occipital epilepsy of childhood (IOEC-G)—have been clearly described and reported. It is also known that a significant percentage of children with IFEC present what were named atypical features in seizures and EEG abnormalities. We are studying here the small number of patients with IFEC who not only present atypical features, but also evolve into the spectrum of epileptic encephalopathies related with continuous spike-and-wave during sleep (CSWSS) or electrical status epilepticus during sleep (ESES), which includes atypical benign focal epilepsy of childhood, status of BCECTS, Landau-Kleffner syndrome, and CSWSS or ESES syndrome. We also emphasize that some patients with these encephalopathic course of IFEC present a mix or a sequence in time of the four mentioned subsyndromes.
Exits in order: How crowding affects particle lifetimes
Authors: Penington Catherine J. , Baker Ruth E. , Simpson Matthew J.
Published: June 2016

Diffusive processes are often represented using stochastic random walk frameworks. The amount of time taken for an individual in a random walk to intersect with an absorbing boundary is a fundamental property that is often referred to as the particle lifetime, or the first passage time. The mean lifetime of particles in a random walk model of diffusion is related to the amount of time required for the diffusive process to reach a steady state. Mathematical analysis describing the mean lifetime of particles in a standard model of diffusion without crowding is well known. However, the lifetime of agents in a random walk with crowding has received much less attention. Since many applications of diffusion in biology and biophysics include crowding effects, here we study a discrete model of diffusion that incorporates crowding. Using simulations, we show that crowding has a dramatic effect on agent lifetimes, and we derive an approximate expression for the mean agent lifetime that includes crowding effects. Our expression matches simulation results very well, and highlights the importance of crowding effects that are sometimes overlooked.
On the properties of a bundle of flexible actin filaments in an optical trap
Authors: Perilli Alessia , Pierleoni Carlo , Ciccotti Giovanni , Ryckaert Jean-Paul
Published: June 2016

We establish the statistical mechanics framework for a bundle of Nf living and uncrosslinked actin filaments in a supercritical solution of free monomers pressing against a mobile wall. The filaments are anchored normally to a fixed planar surface at one of their ends and, because of their limited flexibility, they grow almost parallel to each other. Their growing ends hit a moving obstacle, depicted as a second planar wall, parallel to the previous one and subjected to a harmonic compressive force. The force constant is denoted as the trap strength while the distance between the two walls as the trap length to make contact with the experimental optical trap apparatus. For an ideal solution of reactive filaments and free monomers at fixed free monomer chemical potential μ1, we obtain the general expression for the grand potential from which we derive averages and distributions of relevant physical quantities, namely, the obstacle position, the bundle polymerization force, and the number of filaments in direct contact with the wall. The grafted living filaments are modeled as discrete Wormlike chains, with F-actin persistence length ℓp, subject to discrete contour length variations ±d (the monomer size) to model single monomer (de)polymerization steps. Rigid filaments (ℓp = ∞), either isolated or in bundles, all provide average values of the stalling force in agreement with Hill’s predictions FsH=NfkBTln(ρ1/ρ1c)/d, independent of the average trap length. Here ρ1 is the density of free monomers in the solution and ρ1c its critical value at which the filament does not grow nor shrink in the absence of external forces. Flexible filaments (ℓp < ∞) instead, for values of the trap strength suitable to prevent their lateral escape, provide an average bundle force and an average trap length slightly larger than the corresponding rigid cases (few percents). Still the stalling force remains nearly independent on the average trap length, but results from the product of two strongly L-dependent contributions: the fraction of touching filaments ∝〈L〉O.T.2 and the single filament buckling force ∝〈L〉O.T.−2.
Accelerating ring-polymer molecular dynamics with parallel-replica dynamics
Authors: Lu Chun-Yaung , Perez Danny , Voter Arthur F.
Published: June 2016

Nuclear quantum effects are important for systems containing light elements, and the effects are more prominent in the low temperature regime where the dynamics also becomes sluggish. We show that parallel replica (ParRep) dynamics, an accelerated molecular dynamics approach for infrequent-event systems, can be effectively combined with ring-polymer molecular dynamics, a semiclassical trajectory approach that gives a good approximation to zero-point and tunneling effects in activated escape processes. The resulting RP-ParRep method is a powerful tool for reaching long time scales in complex infrequent-event systems where quantum dynamics are important. Two illustrative examples, symmetric Eckart barrier crossing and interstitial helium diffusion in Fe and Fe–Cr alloy, are presented to demonstrate the accuracy and long-time scale capability of this approach.
Numerical linearized MHD model of flapping oscillations
Authors: Korovinskiy D. B. , Ivanov I. B. , Semenov V. S. , Erkaev N. V. , Kiehas S. A.
Published: June 2016

Kink-like magnetotail flapping oscillations in a Harris-like current sheet with earthward growing normal magnetic field component Bz are studied by means of time-dependent 2D linearized MHD numerical simulations. The dispersion relation and two-dimensional eigenfunctions are obtained. The results are compared with analytical estimates of the double-gradient model, which are found to be reliable for configurations with small Bz up to values ∼0.05 of the lobe magnetic field. Coupled with previous results, present simulations confirm that the earthward/tailward growth direction of the Bz component acts as a switch between stable/unstable regimes of the flapping mode, while the mode dispersion curve is the same in both cases. It is confirmed that flapping oscillations may be triggered by a simple Gaussian initial perturbation of the Vz velocity.
Optical spectroscopy and band gap analysis of hybrid improper ferroelectric Ca3Ti2O7
Authors: Cherian Judy G. , Birol Turan , Harms Nathan C. , Gao Bin , Cheong Sang-Wook , Vanderbilt David , Musfeldt Janice L.
Published: June 2016

We bring together optical absorption spectroscopy, photoconductivity, and first principles calculations to reveal the electronic structure of the room temperature ferroelectric Ca3Ti2O7. The 3.94 eV direct gap in Ca3Ti2O7 is charge transfer in nature and noticeably higher than that in CaTiO3 (3.4 eV), a finding that we attribute to dimensional confinement in the n = 2 member of the Ruddlesden-Popper series. While Sr substitution introduces disorder and broadens the gap edge slightly, oxygen deficiency reduces the gap to 3.7 eV and gives rise to a broad tail that persists to much lower energies.
Deformation of a super-elastic NiTiNb alloy with controllable stress hysteresis
Authors: Cai S. , Schaffer J. E. , Ren Y. , Wang L.
Published: June 2016

Room temperature deformation of a Ni46.7Ti42.8Nb10.5 alloy was studied by in-situ synchrotron X-ray diffraction. Compared to binary NiTi alloy, the Nb dissolved in the matrix significantly increased the onset stress for Stress-Induced Martensite Transformation (SIMT). The secondary phase, effectively a Nb-nanowire dispersion in a NiTi-Nb matrix, increased the elastic stiffness of the bulk material, reduced the strain anisotropy in austenite families by load sharing during SIMT, and increased the stress hysteresis by resisting reverse phase transformation during unloading. The stress hysteresis can be controlled over a wide range by heat treatment through its influences on the residual stress of the Nb-nanowire dispersion and the stability of the austenite.
Optofluidic distributed feedback lasers with evanescent pumping: Reduced threshold and angular dispersion analysis
Authors: Karl Markus , Whitworth Guy L. , Schubert Marcel , Dietrich Christof P. , Samuel Ifor D. W. , Turnbull Graham A. , Gather Malte C.
Published: June 2016

We demonstrate an evanescently pumped water-based optofluidic distributed feedback (DFB) laser with a record low pump threshold of ETH=520 nJ. The low threshold results from an optimized mode shape, which is achieved by a low refractive index substrate, and from the use of a mixed-order DFB grating. Investigating the photonic band structure via angular dispersion analysis both above and below lasing threshold allows us to measure the refractive index of the liquid gain layer and to determine the device parameters such as the waveguide core layer thickness. We show that it is possible to tailor the divergence of the lasing emission by varying the number of second order grating periods used for outcoupling.
Sputtering of silicon membranes with nanoscale thickness
Authors: Hobler Gerhard , Nietiadi Maureen L. , Bradley R. Mark , Urbassek Herbert M.
Published: June 2016

A theoretical study of forward and backward sputtering produced by the impact of single 20 keV Ar ions on freestanding amorphous Si membranes is carried out. We use three techniques: Monte Carlo (MC) and molecular dynamics (MD) simulations, as well as analytical theory based on the Sigmund model of sputtering. We find that the analytical model provides a fair description of the simulation results if the film thickness d exceeds about 10%–30% of the mean depth of energy deposition a. In this regime, backward sputtering is nearly independent of the membrane thickness and forward sputtering shows a maximum for thicknesses d≈a. The dependence of forward sputtering on the ion's incidence angle shows a qualitative change as a function of d: while for d≲a, the forward sputter yield has a maximum at oblique incidence angles, the maximum occurs at normal incidence for d≳a. As the membrane thickness is reduced below 0.1–0.3a, the theory's predictions increasingly deviate from the MC results. For example, the predicted forward sputter yield approaches a finite value but the MC result tends to zero. This behavior is interpreted in terms of energy deposition and sputtering efficiency. Near-perfect agreement is observed between the sputter yields calculated by MD and MC simulations even for the thinnest membranes studied (d = 5 Å).
Extracting flat-field images from scene-based image sequences using phase correlation
Authors: Caron James N. , Montes Marcos J. , Obermark Jerome L.
Published: June 2016

Flat-field image processing is an essential step in producing high-quality and radiometrically calibrated images. Flat-fielding corrects for variations in the gain of focal plane array electronics and unequal illumination from the system optics. Typically, a flat-field image is captured by imaging a radiometrically uniform surface. The flat-field image is normalized and removed from the images. There are circumstances, such as with remote sensing, where a flat-field image cannot be acquired in this manner. For these cases, we developed a phase-correlation method that allows the extraction of an effective flat-field image from a sequence of scene-based displaced images. The method uses sub-pixel phase correlation image registration to align the sequence to estimate the static scene. The scene is removed from sequence producing a sequence of misaligned flat-field images. An average flat-field image is derived from the realigned flat-field sequence.
Hybrid thermoelectric piezoelectric generator
Authors: Montgomery D. S. , Hewitt C. A. , Carroll D. L.
Published: June 2016

This work presents an integration of flexible thermoelectric and piezoelectric materials into a single device structure. This device architecture overcomes several prohibitive issues facing the combination of traditional thermoelectric and piezoelectric generators, while optimizing performance of the combined power output. The structure design uses a carbon nanotube/polymer thin film as a flexible thermoelectric generator that doubles as an electrode on a piezoelectric generator made of poly(vinylidene fluoride). An example 2 × 2 array of devices is shown to generate 89% of the maximum thermoelectric power, and provide 5.3 times more piezoelectric voltage when compared with a traditional device.
First-principles study of crystal and electronic structure of rare-earth cobaltites
Authors: Topsakal M. , Leighton C. , Wentzcovitch R. M.
Published: June 2016

Using density functional theory plus self-consistent Hubbard U (DFT + Usc) calculations, we have investigated the structural and electronic properties of the rare-earth cobaltites RCoO3 (R = Pr – Lu). Our calculations show the evolution of crystal and electronic structure of the insulating low-spin RCoO3 with increasing rare-earth atomic number (decreasing ionic radius), including the invariance of the Co-O bond distance (dCo–O), the decrease of the Co-O-Co bond angle (Θ), and the increase of the crystal field splitting (ΔCF) and band gap energy (Eg). Agreement with experiment for the latter improves considerably with the use of DFT + Usc and all trends are in good agreement with the experimental data. These trends enable a direct test of prior rationalizations of the trend in spin-gap associated with the spin crossover in this series, which is found to expose significant issues with simple band based arguments. We also examine the effect of placing the rare-earth f-electrons in the core region of the pseudopotential. The effect on lattice parameters and band structure is found to be small, but distinct for the special case of PrCoO3 where some f-states populate the middle of the gap, consistent with the recent reports of unique behavior in Pr-containing cobaltites. Overall, this study establishes a foundation for future predictive studies of thermally induced spin excitations in rare-earth cobaltites and similar systems.
ZnO nanolasers on graphene films
Authors: Baek Hyeonjun , Park Jun Beom , Park Jong-woo , Hyun Jerome K. , Yoon Hosang , Oh Hongseok , Yoon Jiyoung
Published: June 2016

We grew and characterized zinc oxide (ZnO) nanolasers on graphene films. By using graphene as a growth medium, we were able to prepare position-controlled and vertically aligned ZnO nanotube lasers. The ZnO nanolasers grown on graphene films showed good optical characteristics, evidenced by a low lasing threshold. Furthermore, the nanolaser/graphene system was easily lifted off the original substrate and transferred onto foreign substrates. The lasing performance was observed to be significantly enhanced by depositing a layer of silver on the back of the graphene film during this transfer process, which was quantitatively investigated using finite-difference time-domain simulations. Due to the wide selection of substrates enabled by the use of graphene films, our results suggest promising strategies for preparing practical nanolasers with improved performance.
Effect of low-temperature post-growth annealing on anisotropic strain in epitaxial Fe layers deposited on GaAs(001)
Authors: Tholapi R. , Liefeith L. , Ekindorf G. , Perumal K. , Slobodskyy T. , Hansen W.
Published: June 2016

We study the effect of low-temperature post growth annealing on the Fe layer in an epitaxial Fe/GaAs(001) heterojunction. High resolution X-ray diffraction and X-ray reflectivity were used to probe the Fe layer before and after annealing. No change in morphological features like annealing induced intermixing and thickness variation of the Fe layer are observed. However, annealing leads to increase in the compressive strain and improves isotropy of the ferromagnetic layer as revealed by measuring both lateral and out-of-plane lattice components.
Nanoslit design for ion conductivity gradient enhanced dielectrophoresis for ultrafast biomarker enrichment in physiological media
Authors: Rohani Ali , Varhue Walter , Liao Kuo-Tang , Chou Chia-Fu , Swami Nathan S.
Published: June 2016

Selective and rapid enrichment of biomolecules is of great interest for biomarker discovery, protein crystallization, and in biosensing for speeding assay kinetics and reducing signal interferences. The current state of the art is based on DC electrokinetics, wherein localized ion depletion at the microchannel to nanochannel interface is used to enhance electric fields, and the resulting biomarker electromigration is balanced against electro-osmosis in the microchannel to cause high degrees of biomarker enrichment. However, biomarker enrichment is not selective, and the levels fall off within physiological media of high conductivity, due to a reduction in ion concentration polarization and electro-osmosis effects. Herein, we present a methodology for coupling AC electrokinetics with ion concentration polarization effects in nanoslits under DC fields, for enabling ultrafast biomarker enrichment in physiological media. Using AC fields at the critical frequency necessary for negative dielectrophoresis of the biomarker of interest, along with a critical offset DC field to create proximal ion accumulation and depletion regions along the perm-selective region inside a nanoslit, we enhance the localized field and field gradient to enable biomarker enrichment over a wide spatial extent along the nanoslit length. While enrichment under DC electrokinetics relies solely on ion depletion to enhance fields, this AC electrokinetic mechanism utilizes ion depletion as well as ion accumulation regions to enhance the field and its gradient. Hence, biomarker enrichment continues to be substantial in spite of the steady drop in nanostructure perm-selectivity within physiological media.
Acoustic energy harvesting based on a planar acoustic metamaterial
Authors: Qi Shuibao , Oudich Mourad , Li Yong , Assouar Badreddine
Published: June 2016

We theoretically report on an innovative and practical acoustic energy harvester based on a defected acoustic metamaterial (AMM) with piezoelectric material. The idea is to create suitable resonant defects in an AMM to confine the strain energy originating from an acoustic incidence. This scavenged energy is converted into electrical energy by attaching a structured piezoelectric material into the defect area of the AMM. We show an acoustic energy harvester based on a meta-structure capable of producing electrical power from an acoustic pressure. Numerical simulations are provided to analyze and elucidate the principles and the performances of the proposed system. A maximum output voltage of 1.3 V and a power density of 0.54 μW/cm3 are obtained at a frequency of 2257.5 Hz. The proposed concept should have broad applications on energy harvesting as well as on low-frequency sound isolation, since this system acts as both acoustic insulator and energy harvester.
Development and characterization of monolithic multilayer Laue lens nanofocusing optics
Authors: Nazaretski E. , Xu W. , Bouet N. , Zhou J. , Yan H. , Huang X. , Chu Y. S.
Published: June 2016

We have developed an experimental approach to bond two independent linear Multilayer Laue Lenses (MLLs) together. A monolithic MLL structure was characterized using ptychography at 12 keV photon energy, and we demonstrated 12 nm and 24 nm focusing in horizontal and vertical directions, respectively. Fabrication of 2D MLL optics allows installation of these focusing elements in more conventional microscopes suitable for x-ray imaging using zone plates, and opens easier access to 2D imaging with high spatial resolution in the hard x-ray regime.
Electrochemical kinetics and dimensional considerations, at the nanoscale
Authors: Yamada H. , Bandaru P. R.
Published: June 2016

It is shown that the consideration of the density of states variation in nanoscale electrochemical systems yields modulations in the rate constant and concomitant electrical currents. The proposed models extend the utility of Marcus-Hush-Chidsey (MHC) kinetics to a larger class of materials and could be used as a test of dimensional character. The implications of the study are of much significance to an understanding and modulation of charge transfer nanostructured electrodes.
Phonocatalysis. An ab initio simulation experiment
Authors: Kim Kwangnam , Kaviany Massoud
Published: June 2016

Using simulations, we postulate and show that heterocatalysis on large-bandgap semiconductors can be controlled by substrate phonons, i.e., phonocatalysis. With ab initio calculations, including molecular dynamic simulations, the chemisorbed dissociation of XeF6 on h-BN surface leads to formation of XeF4 and two surface F/h-BN bonds. The reaction pathway and energies are evaluated, and the sorption and reaction emitted/absorbed phonons are identified through spectral analysis of the surface atomic motion. Due to large bandgap, the atomic vibration (phonon) energy transfer channels dominate and among them is the match between the F/h-BN covalent bond stretching and the optical phonons. We show that the chemisorbed dissociation (the pathway activation ascent) requires absorption of large-energy optical phonons. Then using progressively heavier isotopes of B and N atoms, we show that limiting these high-energy optical phonons inhibits the chemisorbed dissociation, i.e., controllable phonocatalysis.
Evaluating the Sharing Stories youth theatre program: an interactive theatre and drama‐based strategy for sexual health promotion among multicultural youth
Authors: Roberts Meagan , Lobo Roanna , Sorenson Anne
Published: June 2016

Issue addressed

Rates of sexually transmissible infections among young people are high, and there is a need for innovative, youth‐focused sexual health promotion programs. This study evaluated the effectiveness of the Sharing Stories youth theatre program, which uses interactive theatre and drama‐based strategies to engage and educate multicultural youth on sexual health issues. The effectiveness of using drama‐based evaluation methods is also discussed.

Methods

The youth theatre program participants were 18 multicultural youth from South East Asian, African and Middle Eastern backgrounds aged between 14 and 21 years. Four sexual health drama scenarios and a sexual health questionnaire were used to measure changes in knowledge and attitudes.

Results

Participants reported being confident talking to and supporting their friends with regards to safe sex messages, improved their sexual health knowledge and demonstrated a positive shift in their attitudes towards sexual health. Drama‐based evaluation methods were effective in engaging multicultural youth and worked well across the cultures and age groups.

Conclusions

Theatre and drama‐based sexual health promotion strategies are an effective method for up‐skilling young people from multicultural backgrounds to be peer educators and good communicators of sexual health information. Dramabased evaluation methods are engaging for young people and an effective way of collecting data from culturally diverse youth.

So what?

This study recommends incorporating interactive and arts‐based strategies into sexual health promotion programs for multicultural youth. It also provides guidance for health promotion practitioners evaluating an arts‐based health promotion program using arts‐based data collection methods.
The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols
Authors: Schwenke G. D. , Haigh B. M.
Published: June 2016

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate.
Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate.
Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment.
Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.
Setting the standard
Authors: Delarue Steven , Ghyselen Anne-Sophie
Published: June 2016

In this paper, Grondelaers and Van Hout’s statement that “the highest nonvirtual stratum of Belgian Dutch is documented by the speech of Belgian teachers” (2011, p. 219) is put to the test. Using production data from two corpora of contemporary spoken Dutch, mixed models binary logistic regression was carried out, focussing on 11 phonological and morpho-syntactic variables. The results show that teachers indeed use significantly less non-standard variants than other highly educated professionals. Moreover, there is also a difference between teachers of Dutch and teachers of other school subjects. By means of an exploratory content analysis of the sociolinguistic interviews, a few possible explanatory factors are discussed: teacher training, hypocorrection, and a difference in linguistic expectations. Especially the latter factor seems to be in play: teachers feel more pressured to adhere to the standard norm than the informants from the ‘laymen’ corpus.
Reflexive paradigms in Khaling
Authors: Jacques Guillaume , Lahaussois Aimée , Rai Dhan Bahadur
Published: June 2016

Khaling, like other Kiranti languages, has a Reflexive / Middle suﬃx-si, the main function of which is to reduce the valence of verbs. The present paper describes the complex morphological alternations observed in the reflexive paradigms, and provides a detailed account of the various meanings of the -si derivation in Khaling.
Reflexive derivations in Thulung
Authors: Lahaussois Aimée
Published: June 2016

Thulung Rai, an endangered Tibeto-Burman language spoken in Eastern Nepal, presents two derivational suffixes associated with reflexivization: -siand -s. The first, -si, is quite productive, found in complete paradigms, and derives reflexives, reciprocals, antipassives and anticausatives from transitive verbs (and occasionally from intransitive verbs). The second marker, -s, is more difficult to analyze: it has a limited distribution in verb paradigms, only appearing with 1pi and 3sg forms, and appears in a number of different contexts: it is found with the same types of derivations as -sibut also — in some cases obligatorily, in others optionally — with verbs that do not have reflexive (or related) functions. It is even found with some transitive verbs. In this presentation, I will propose an analysis of the phenomena above based on elicited and narrative data I have collected in the field. The -sin fact has multiple, albeit related, origins: it is a phonological reduction of -siin certain circumstances, while in others it appears to be an older reflexivizing suffix which has been integrated, to different degrees, into verb morphology. With transitives, it appears to be a trace reflecting the complex derivational history of verbs which are derived from intransitives.
Applying Cognitive Linguistics
Authors: Piquer-Píriz Ana María , Alejo-González Rafael
Published: June 2016

In recent years, Cognitive Linguistics (CL) has established itself not only as a solid theoretical approach but also as an important source from which different applications to other fields have emerged. In this introductory article, we explore some of the current, most relevant topics in applied CL-oriented studies grouped into three main strands: Analyses of figurative language (both metaphor and metonymy) in use, constructions and typology. An outline of the contents of the eight chapters included in this special issue is provided, explaining their contributions to these research areas and highlighting their methodological rigour.