bluuebunny/crossref_metadata_2025 huggingface dataset:
Area‐delay‐power‐efficient architecture for folded two‐dimensional discrete wavelet transform by multiple lifting computation
Authors: Mohanty Basant Kumar , Meher Pramod K.
Published: June 2014

Multiple lifting computation could be performed for block processing of two‐dimensional (2D) discrete wavelet transform (DWT) by combined‐lifting (CLF) or separated‐lifting (SLF) approaches. CLF and SLF have the same computational complexities but they differ by their register requirements. In this study, the authors have chosen CLF for row processing and SLF for column processing, and suggested an efficient scheduling scheme for the computation of block‐based lifting 2D DWT. Based on this approach, the authors have derived a parallel‐pipeline structure for high‐throughput implementation of one‐level lifting 2D DWT. The authors have partitioned the multilevel 2D DWT computation appropriately and mapped that to a folded structure where the frame‐buffer size is independent of input block size. The proposed structure requires 3N on‐chip memory words, which is the lowest among all the existing similar structures. Compared with the best of the existing block‐based structures for the one‐level DWT, the proposed structure involves less on‐chip memory words, requires the same number of multipliers and adders and offers the same throughput rate. The application specific integrated circuit (ASIC) synthesis result shows that the proposed structure involves significantly less area‐delay‐product and less energy per image than those of the best of the available designs.
Three to single‐phase high‐power quality switch‐mode cycloconverter
Authors: Azam Ali
Published: June 2014

A new switch mode power supply‐based cycloconverter circuit has been presented. Proposed circuit configuration offers conspicuous advantages over traditional 12‐SCR (silicon controlled rectifier) cycloconverter. It facilitates output voltage and output frequency to be either greater or smaller than the input voltage and input frequency. The circuit operates with reduced total harmonic distortion (below 15%), improved efficiency (above 80%) and highly improved power factor (above 95%) for both resistive and inductive load. Moreover, only 4 insulated gate bipolar transistors (IGBTs) are required instead of 12 SCR. Reduced number of switches increases circuit longevity while reducing pulse generation complexity. As voltage driven switch is being used, it can be operated easily using digital IC or microcontrollers. In contrary to traditional cycloconverter, input AC voltage is made unidirectional by employing a full bridge three phase uncontrolled diode bridge rectifier. One positive and one negative converter differentially connected across load ensure proper output voltage and frequency by utilising appropriate switching pulse. As SMPS topology has been incorporated, the circuit can operate in four quadrant mode at voltage–frequency plane. Integration of fuzzy logic control provides better stability and grip over output voltage and frequency. Meticulous details of operation and circuit performance are presented in this study.
Extended switching algorithms based space vector control for five‐level quasi‐Z‐source inverter with coupled inductors
Authors: Banaei Mohamad Reza , Oskouei Aida Baghbany , Dehghanzadeh Alireza
Published: June 2014

This study combines quasi‐Z‐source into the five‐level inverter using coupled inductors. The suggested circuit consists of only one dc voltage source, one quasi‐Z‐network, six power switches and only one set of coupled inductors. In this topology, the output voltage amplitude is not limited to dc voltage source and it is reliable and higher efficiency because of quasi‐Z‐network presence. This study also proposes new switching algorithms for the inverter based on pulse width modulation (PWM) and space vector control (SVC) algorithms, which cause boosting capability of output voltage with low total harmonic distortion (THD). This PWM algorithm is particular one, which calculates dwelling time for each switch in every sample time. The proposed SVC algorithm generates a voltage vector with very low harmonic distortion and reduced switching frequency. The performance of proposed inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI‐1716 data acquisition system. These results demonstrate the proposed inverter with suggested algorithm can generate a wide range of load voltage.
Impedance network design and its critical value prediction of tapped‐inductor single‐stage boost inverter
Authors: Zhou Yufei , Huang Wenxin , Zhao Jianwu , Zhao Ping
Published: June 2014

This study proposes a high inversion gain single‐stage boost inverter, which introduces a tapped inductor impedance network, including one tapped inductor and two diodes, to add to the front end of traditional voltage‐source inverter, called tapped‐inductor single‐stage boost inverter (TISSBI). The TISSBI has the merits of high inversion gain, common ground of input and dc‐bus, continuous input current and reduced capacitor voltage stress. This study also presents all the possible steady states of the TISSBI proposed. It is shown that, in addition to the desired three steady states, an operating cycle can contain another four abnormal states that do not contribute to the power conversion process. These four states can be avoided by selecting suitable value of capacitance and inductance. By using the equations derived in the steady‐state analysis, this study presents guidelines to design the impedance network accurately. Experimental results are provided to verify the effectiveness of the proposed circuit, the design method of impedance network and demonstrate the appearance of the four states when the capacitors and inductors are smaller than their critical values.
Particle filter based on the lifting scheme of observations
Authors: Hu Zhentao , Liu Xianxing , Hu Yumei
Published: June 2014

Recently, particle filter (PF) has been introduced as an effective means to solve the state estimation problems of non‐linear and non‐Gaussian system. If the observation sensor accuracy is lower, the measurement of importance weights according to the observation likelihood degree will result in the performance degeneration of general PF. Aiming at this problem, the authors propose a novel scheme of observations to enhance the reliability and stability of importance weights. In realisation of algorithm, firstly, a set of virtual observations are constructed on the basis of the current observation and the priori information of observation noise, also known as the accuracy of sensor. Secondly, combining with the distribution characteristics of virtual observations, the importance weights of particle are calculated by the weight fusion. From the derivation, it is easy to know that the variance of particles importance weights is decreased, and the adverse effect on importance weights from the randomness of observation noise is improved. The theoretical analysis and experimental results show that the proposed method outperforms the general PF.
Ambulatory Spine Surgery: A Survey Study
Authors: Baird Evan O. , Brietzke Sasha C. , Weinberg Alan D. , McAnany Steven J. , Qureshi Sheeraz A. , Cho Samuel K. , Hecht Andrew C.
Published: June 2014

Study Design

Cross-sectional study.

Objective

To assess the current practices of spine surgeons performing ambulatory surgery in the United States.

Methods

An electronic survey was distributed to members of the International Society for the Advancement of Spine Surgery. Data were initially examined in a univariate manner; variables with a p value < 0.25 were entered into a multiple logistic regression model. All statistical analyses were performed using the SAS System software Version 9.2 (SAS Institute, Inc., Cary, North Carolina, United States).

Results

Overall, 84.2% of respondents performed some manner of ambulatory spine surgery, and 49.1% were investors in an ambulatory surgery center. Surgeon investors in ambulatory surgery centers were more likely to perform procedures of increased complexity than noninvestors, though limited data precluded a statistical correlation. Surgeons in private practice were more likely to perform ambulatory surgery (94.3%; p = 0.0176), and nonacademic surgeons were both more likely to invest in ambulatory surgery centers ( p = 0.0024) and perform surgery at least part of the time in a surgery center ( p = 0.0039).

Conclusions

Though the numbers were too few to calculate statistical significance, there was a trend toward the performance of high-risk procedures on an ambulatory basis being undertaken by those with investment status in an ambulatory center. It is possible that this plays a role in the decision to perform these procedures in this setting versus that of a hospital, where a patient may have better access to care should a complication arise requiring emergent assessment and treatment by a physician. This decision should divest itself of financial incentives and focus entirely on patient safety.
Response to “Comment on ‘Stationary self-focusing of Gaussian laser beam in relativistic thermal quantum plasma’” [Phys. Plasmas 21, 064701 (2014)]
Authors: Patil S. D. , Takale M. V.
Published: June 2014

Habibi and Ghamari have presented a Comment on our paper [Phys. Plasmas 20, 072703 (2013)] by examining quantum dielectric response in thermal quantum plasma. They have modeled the relativistic self-focusing of Gaussian laser beam in cold and warm quantum plasmas and reported that self-focusing length does not change in both situations. In this response, we have reached the following important conclusions about the comment itself.
Controllable elastocapillary folding of three-dimensional micro-objects by through-wafer filling
Authors: Legrain A. , Janson T. G. , Berenschot J. W. , Abelmann L. , Tas N. R.
Published: June 2014

We present a technique for the controllable capillary folding of planar silicon nitride templates into 3D micro-structures by means of through-wafer liquid application. We demonstrate for the first time hydro-mechanical, repeatable, actuation of capillary folded structures via the addition or retraction of water on demand. Silicon nitride objects with a central through-wafer tube are connected to a dedicated pumping system to enable assembly. When remaining wetted, structures can be assembled and reopened up to several dozens of times and still reach the same final folding angle. Objects were actuated up to 60 times without signs of wear. Extracted curves from our self-folding experiments are in agreement with our two-dimensional elastocapillary folding model. When structures are allowed to dry in between foldings, we observe an increase in the bending stiffness of the hinges, by a factor 50% after first folding and subsequent drying. This stiffening causes a decrease of the finally achieved angle. Residue from the fabrication process found on the structures after folding is suspected to be the cause of the stiffening.
Dust kinetic Alfvén waves and streaming instability in a non-Maxwellian magnetoplasma
Authors: Rubab N. , Ali S. , Jaffer G.
Published: June 2014

The dust kinetic Alfvén wave (DKAW) instability is studied in a uniform dusty magnetoplasma by incorporating the superthermality effects of the electrons and perpendicularly streaming κ-distributed ions. The dispersion relation of the DKAW instability is investigated in the low-βd Lorentzian plasma limit. The solutions are analyzed for various scenarios of dusty and dusty-free plasmas. It is shown that the presence of dust particles and the cross-field superthermal ions sensibly modify the dispersion characteristics of the low-frequency DKAW. The present results are only valid for a frequency regime well below the dust cyclotron frequency. Numerical calculations are carried out for the growth rates by taking different dust parameters into account. It is found that the nonthermality is more effective for the dust kinetic Alfvén waves in the perpendicular direction as compared to the parallel one. The relevance of the results to the low-βd regions of space and astrophysical plasmas is highlighted.
Improvement of the quality of graphene-capped InAs/GaAs quantum dots
Authors: Othmen Riadh , Rezgui Kamel , Cavanna Antonella , Arezki Hakim , Gunes Fethullah , Ajlani Hosni , Madouri Ali , Oueslati Meherzi
Published: June 2014

In this paper, we study the transfer of graphene onto InAs/GaAs quantum dots (QDs). The graphene is first grown on Cu foils by chemical vapor deposition and then polymer Polymethyl Methacrylate (PMMA) is deposited on the top of graphene/Cu. High quality graphene sheet has been obtained by lowering the dissolving rate of PMMA using vapor processing. Uncapped as well as capped graphene InAs/GaAs QDs have been studied using optical microscopy, scanning electron microscopy, and Raman spectroscopy. We gather from this that the average shifts Δω of QDs Raman peaks are reduced compared to those previously observed in graphene and GaAs capped QDs. The encapsulation by graphene makes the indium atomic concentration intact in the QDs by the reduction of the strain effect of graphene on QDs and the migration of In atoms towards the surface. This gives us a new hetero-structure graphene–InAs/GaAs QDs wherein the graphene plays a key role as a cap layer.
High resolution analysis of three bands of the electronic transition A2Σ+-X2Π of N2O+ radical: 100-000, 000-001, and 001-001
Authors: Lessa L. L. , de Cândido S. D. , Fellows C. E.
Published: June 2014

In this article three vibrational bands of the electronic transition A2Σ+-X2Π of the N2O+ radical (100-000, 000-001, and 001-001) are analysed through high resolution Fourier transform spectroscopy. The N2O+ radical was produced by Penning ionization of N2O by colliding with metastable atoms of He(23S) in a reaction chamber. The spectra was recorded in a spectral range of 24 500–30 000 cm−1 and obtained from 200 coadded interferograms recorded at an apodized resolution of 0.08 cm−1. Through a recursive way, the wavenumbers of the correspondent rotational transitions were reduced into molecular constants, improving the values previously reported. New values for the first vibrational energies \documentclass[12pt]{minimal}\begin{document}$\nu ^{\prime }_1$\end{document}ν1′, \documentclass[12pt]{minimal}\begin{document}$\nu ^{\prime \prime } _3$\end{document}ν3″, and \documentclass[12pt]{minimal}\begin{document}$\nu ^{\prime }_3$\end{document}ν3′ are also obtained and compared with previous values reported in the literature.
The kinetics of mutarotation in L-fucose as monitored by dielectric and infrared spectroscopy
Authors: Kossack Wilhelm , Kipnusu Wycliffe Kiprop , Dulski Mateusz , Adrjanowicz Karolina , Madejczyk Olga , Kaminska Ewa , Mapesa Emmanuel Urandu , Tress Martin , Kaminski Kamil , Kremer Friedrich
Published: June 2014

Fourier Transform Infrared Spectroscopy and Broadband Dielectric Spectroscopy are combined to trace kinetics of mutarotation in L-fucose. After quenching molten samples down to temperatures between T = 313 K and 328 K, the concentrations of two anomeric species change according to a simple exponential time dependence, as seen by an increase in absorbance of specific IR-vibrations. In contrast, the dielectric spectra reveal a slowing down of the structural (α-) relaxation process according to a stretched exponential time dependence (stretching exponent of 1.5 ± 0.2). The rates of change in the IR absorption for α- and β-fucopyranose are (at T = 313 K) nearly one decade faster than that of the intermolecular interactions as measured by the shift of the α-relaxation. This reflects the fact that the α-relaxation monitors the equilibration at a mesoscopic length scale, resulting from fluctuations in the anomeric composition.
Structural anisotropic properties of a-plane GaN epilayers grown on r-plane sapphire by molecular beam epitaxy
Authors: Lotsari A. , Kehagias Th. , Tsiakatouras G. , Tsagaraki K. , Katsikini M. , Arvanitidis J. , Christofilos D. , Ves S. , Komninou Ph. , Georgakilas A. , Dimitrakopulos G. P.
Published: June 2014

Heteroepitaxial non-polar III-Nitride layers may exhibit extensive anisotropy in the surface morphology and the epilayer microstructure along distinct in-plane directions. The structural anisotropy, evidenced by the “M”-shape dependence of the (112¯0) x-ray rocking curve widths on the beam azimuth angle, was studied by combining transmission electron microscopy observations, Raman spectroscopy, high resolution x-ray diffraction, and atomic force microscopy in a-plane GaN epilayers grown on r-plane sapphire substrates by plasma-assisted molecular beam epitaxy (PAMBE). The structural anisotropic behavior was attributed quantitatively to the high dislocation densities, particularly the Frank-Shockley partial dislocations that delimit the I1 intrinsic basal stacking faults, and to the concomitant plastic strain relaxation. On the other hand, isotropic samples exhibited lower dislocation densities and a biaxial residual stress state. For PAMBE growth, the anisotropy was correlated to N-rich (or Ga-poor) conditions on the surface during growth, that result in formation of asymmetric a-plane GaN grains elongated along the c-axis. Such conditions enhance the anisotropy of gallium diffusion on the surface and reduce the GaN nucleation rate.
Broadband infrared emission of Pr3+-doped BaGd2(MoO4)4 for optical amplifier
Authors: Guan Ying , Tsuboi Taiju , Huang Yanlin , Huang Wei
Published: June 2014

Contrary to most Pr3+-doped materials, Pr3+-doped BaGd2(MoO4)4 crystals do not generate the 1320 nm photoluminescence, which is used as an amplifier for O-band optical communications. However, it is found to generate a broad emission band in the wavelength region of 1400–1550 nm with full-width at half-maximum of 130 nm. Pr3+-doped BaGd2(MoO4)4 with broadband near-infrared emission is expected to be useful as an amplifier material in the E- and S-band optical communication systems. Disappearance of the 1320 nm emission in BaGd2(MoO4)4 is explained by the energy gap law with high maximum phonon energy (944 cm−1) of BaGd2(MoO4)4. The 1400–1550 nm emission has the maximum intensity at 1 mol. % Pr3+ concentration. The concentration quenching is understood by cross-relaxation process.
Influence of step morphology on the structural phase transition of the α-Al2O3(0001) surface
Authors: Tosaka Aki , Kitamura Tatsuya , Sugiyama Takuhiro , Koyama Koji , Shigeta Yukichi
Published: June 2014

The structural phase transition from the 1 × 1 to the √31 × √31 ± R9° structure of two types of α-Al2O3(0001) surfaces has been investigated using reflection high-energy electron diffraction. One of the α-Al2O3(0001) surfaces was composed of regularly arranged monolayer steps (M-surface), and the other surface was composed of multiples of bilayer high steps (B-surface). The surface transition from the 1 × 1 to the √31 × √31 ± R9° structure starts at 1200 °C on the M-surface, but the transition occurs at 1600 °C on the B-surface. We discuss the difference in the stability of these surfaces at high temperature from the viewpoint of the stoichiometry near the step edge and conclude that the B-surface is more stable than the M-surface.
First-principles calculations of the indigo encapsulation and adsorption by MgO nanotubes
Authors: Sánchez-Ochoa F. , Cocoletzi Gregorio H. , Canto Gabriel I. , Takeuchi Noboru
Published: June 2014

We have performed ab-initio calculations to investigate the structural and electronic properties of (m,m) chiral magnesium oxide nanotubes, (m,m)MgONTs, to explore the encapsulation, inclusion, and adsorption of dyes (organic molecules) such as Indigo (IND). Studies start by determining the structural parameters of the MgO nanotubes with different diameters and the IND. The indigo encapsulation into the MgONT is studied considering four (m,m) chiralities which yield 4 different NT diameters. In the endohedral functionalization, the indigo is within the NT at a tilt angle as in previous theoretical studies of organic molecules inside carbon and boron-nitride nanotubes. Results show that the encapsulation is a strong exothermic process with the m = 6 case exhibiting the largest encapsulation energy. It is also explored the indigo adsorption on the NT surface in the parallel and perpendicular configurations. The perpendicular configuration of the IND adsorption on the (8,8)MgONT exhibits the largest energy. The indigo inclusion within the NTs meets a potential barrier when m < 6, however this barrier diminishes as the index increases. Additionally, we have determined the total density of states (DOS), partial DOS, electron charge redistributions, and the highest occupied molecular orbital–lowest unoccupied molecular orbital levels for the NTs with m = 6. Very strong binding energies and electron charge transfer from the IND to NTs is present in the atomic structures.
Effects of temperature on intergranular exchange coupling in L1 FePt thin films
Authors: Huang Efrem Y. , Kryder Mark H.
Published: June 2014

The effects of temperature on intergranular exchange coupling for FePt:X:FePt (X = TaOx, SiOx, Cr) sputtered thin film stacks were investigated. In-plane FePt layers separated by a thin layer of segregant were used as an experimental model for the intergranular region in perpendicular recording media. Magnetic hysteresis was measured for varying segregant thicknesses (0.5 nm–1.5 nm) at varying temperatures (300 K–700 K). Exchange coupling energies were calculated using the reversal field, saturation magnetization, and coercivity. The intergranular exchange coupling energy was observed to be well-behaved, decreasing linearly with increasing temperature to 600 K. TaOx resulted in the lowest exchange coupling energy at any given temperature, while SiOx and Cr showed similar decoupling capabilities. At 600 K and beyond, antiferromagnetic behavior was observed. Exchange coupling was found to be negligible at operating temperatures above 600 K even with as little as 0.5 nm of TaOx segregant or 1 nm of SiOx segregant.
Direct writing of continuous and discontinuous sub-wavelength periodic surface structures on single-crystalline silicon using femtosecond laser
Authors: Kuladeep Rajamudili , Sahoo Chakradhar , Narayana Rao Desai
Published: June 2014

Laser-induced ripples or uniform arrays of continuous near sub-wavelength or discontinuous deep sub-wavelength structures are formed on single-crystalline silicon (Si) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Si wafers at normal incidence in air and by immersing them in dimethyl sulfoxide using linearly polarized Ti:sapphire fs laser pulses of ∼110 fs pulse duration and ∼800 nm wavelength. Morphology studies of laser written surfaces reveal that sub-wavelength features are oriented perpendicular to laser polarization, while their morphology and spatial periodicity depend on the surrounding dielectric medium. The formation mechanism of the sub-wavelength features is explained by interference of incident laser with surface plasmon polaritons. This work proves the feasibility of fs laser direct writing technique for the fabrication of sub-wavelength features, which could help in fabrication of advanced electro-optic devices.
Double-stage genetic algorithm for wind farm layout optimization on complex terrains
Authors: Dobrić Goran , Đurišić Željko
Published: June 2014

This paper deals with the problem of optimal wind turbine micro siting on complex terrains. A realistic wind farm terrain can be very complex not only for the topography of the terrain but also for other factors. Such factors are the environmental impact of the wind farm, the costs of land, the costs of access roads, wind turbine installation and maintenance costs, the costs of electrical infrastructure, etc. A grid-based wind farm model that takes all of these factors into consideration is proposed. For the purpose of an optimization algorithm, a double-stage genetic algorithm is proposed. In the first stage, the optimal micro-areas for wind turbine positioning are determined, whereas the second stage defines precise optimal positions of wind turbine foundations. The double-stage genetic algorithm increases the accuracy of wind turbine positioning and decreases the dimensionality of the problem. The algorithm has been tested on a realistic wind farm terrain in Serbia.
Study on the application of closed-loop lake water heat pump systems for lakefront buildings in south China climates
Authors: Chen Xiao , Zhang Guoqiang
Published: June 2014

The performance of closed-loop lake water heat pump (LWHP) systems is primarily influenced by lake area, lake depth, and local climate. In this study, a systemic model for closed-loop LWHP systems was developed for the system performance analysis. Field measurements of the heat transfer coefficient of submerged coils were conducted under various conditions for the purpose of model application. The model has been used for the dynamic simulations of a closed-loop LWHP system in Zhuzhou, a city in south China. The daily average coefficient of performance of the system was found to be within the range of 2.8 to 3.2 in 183 days of the 229-day cooling and heating seasons. The influences of lake area and depth on system performance were analyzed through the comparisons among the hourly entering fluid temperatures in three scenarios. The comparison results indicate that deep lakes are more favorable for cooling performance improvement than for heating performance improvement. For two lakes with identical volume, the deeper lake is more favorable for cooling performance improvement than the larger lake except in September.
Influence of quantum-confined Stark effect on optical properties within trench defects in InGaN quantum wells with different indium content
Authors: Vaitkevičius A. , Mickevičius J. , Dobrovolskas D. , Tuna Ö. , Giesen C. , Heuken M. , Tamulaitis G.
Published: June 2014

The trench defects in InGaN/GaN multiple quantum well structures are studied using confocal photoluminescence (PL) spectroscopy and atomic force microscopy. A strong blueshift (up to ∼280 meV) and an intensity increase (by up to a factor of 700) of the emission are demonstrated for regions enclosed by trench loops. The influence of the difference in the well width inside and outside the trench loops observed by transmission electron microscopy, the compositional pulling effect, the strain relaxation inside the loop, and corresponding reduction in the built-in field on the PL band peak position and intensity were estimated. The competition of these effects is mainly governed by the width of the quantum wells in the structure. It is shown that the PL band blueshift observed within the trench defect loops in the InGaN structures with wide quantum wells is mainly caused by the reduction in efficiency of the quantum-confined Stark effect due to strain relaxation.
Plasmonic terahertz detectors based on a high-electron mobility GaAs/AlGaAs heterostructure
Authors: Białek M. , Witowski A. M. , Orlita M. , Potemski M. , Czapkiewicz M. , Wróbel J. , Umansky V. , Grynberg M. , Łusakowski J.
Published: June 2014

In order to characterize magnetic field (B) tunable THz plasmonic detectors, spectroscopy experiments were carried out at liquid helium temperatures and high magnetic fields on devices fabricated on a high electron mobility GaAs/AlGaAs heterostructure. The samples were either gated (the gate of a meander shape) or ungated. Spectra of a photovoltage generated by THz radiation were obtained as a function of B at a fixed THz excitation from a THz laser or as a function of THz photon frequency at a fixed B with a Fourier spectrometer. In the first type of measurements, the wave vector of magnetoplasmons excited was defined by geometrical features of samples. It was also found that the magnetoplasmon spectrum depended on the gate geometry which gives an additional parameter to control plasma excitations in THz detectors. Fourier spectra showed a strong dependence of the magnetoplasmon resonance amplitude on the conduction-band electron filling factor which was explained within a model of the electron gas heating with THz radiation. The study allows to define both the advantages and limitations of plasmonic devices based on high-mobility GaAs/AlGaAs heterostructures for THz detection at low temperatures and high magnetic fields.
Molecular diffusion on surfaces in the weak friction limit
Authors: Li Chu , Huang Baoling , Cao Liang , Li Zhigang
Published: June 2014

We investigate the diffusion of molecules on solid surfaces and derive a theoretical formula for the diffusion coefficient in the weak friction limit. The formula clearly shows how the potential, friction, and temperature contribute to the diffusion coefficient. Molecular dynamics (MD) simulations of the diffusion of argon molecules on carbon nanotube surfaces are also performed and the theoretical diffusion coefficient formula is shown in good agreement with the MD simulations. Furthermore, by combining the theoretical results in the weak and strong friction limits, an empirical expression for the diffusion coefficient is proposed, which works well for the entire friction regimes.
Mutual phase-locking of planar nano-oscillators
Authors: Xu K. Y. , Li J. , Xiong J. W. , Wang G.
Published: June 2014

Characteristics of phase-locking between Gunn effect-based planar nano-oscillators are studied using an ensemble Monte Carlo (EMC) method. Directly connecting two oscillators in close proximity, e.g. with a channel distance of 200 nm, only results in incoherent oscillations. In order to achieve in-phase oscillations, additional considerations must be taken into account. Two coupling paths are shown to exist between oscillators. One coupling path results in synchronization and the other results in anti-phase locking. The coupling strength through these two paths can be adjusted by changing the connections between oscillators. When two identical oscillators are in the anti-phase locking regime, fundamental components of oscillations are cancelled. The resulting output consists of purely second harmonic oscillations with a frequency of about 0.66 THz. This type of second harmonic generation is desired for higher frequency applications since no additional filter system is required. This transient phase-locking process is further analyzed using Adler's theory. The locking range is extracted, and a criterion for the channel length difference required for realizing phased arrays is obtained. This work should aid in designing nano-oscillator arrays for high power applications and developing directional transmitters for wireless communications.
Substrate-dependent post-annealing effects on the strain state and electrical transport of epitaxial La5/8-yPryCa3/8MnO3 films
Authors: Hu Sixia , Huang Haoliang , Yang Yuanjun , Luo Zhenlin , Yang Mengmeng , Wang Haibo , Dong Yongqi , Hong Bing , He Hao , Bao Jun , Gao Chen
Published: June 2014

Large scale electronic phase separation (EPS) between ferromagnetic metallic and charge-ordered insulating phases in La5/8-yPryCa3/8MnO3 (y = 0.3) (LPCMO) is very sensitive to the structural changes. This work investigates the effects of post-annealing on the strain states and electrical transport properties of LPCMO films epitaxially grown on (001)pc SrTiO3 (tensile strain), LaAlO3 (compressive strain) and NdGaO3 (near-zero strain) substrates. Before annealing, all the films are coherent-epitaxial and insulating through the measured temperature range. Obvious change of film lattice is observed during the post-annealing: the in-plane strain in LPCMO/LAO varies from −1.5% to −0.1% while that in LPCMO/STO changes from 1.6% to 1.3%, and the lattice of LPCMO/NGO keeps constant because of the good lattice-match between LPCMO and NGO. Consequently, the varied film strain leads to the emergence of metal-insulator transitions (MIT) and shift of the critical transition temperature in the electrical transport. These results demonstrate that lattice-mismatch combined with post-annealing is an effective approach to tune strain in epitaxial LPCMO films, and thus to control the EPS and MIT in the films.
Heterogeneous delays making parents synchronized: A coupled maps on Cayley tree model
Authors: Singh Aradhana , Jalan Sarika
Published: June 2014

We study the phase synchronized clusters in the diffusively coupled maps on the Cayley tree networks for heterogeneous delay values. Cayley tree networks comprise of two parts: the inner nodes and the boundary nodes. We find that heterogeneous delays lead to various cluster states, such as; (a) cluster state consisting of inner nodes and boundary nodes, and (b) cluster state consisting of only boundary nodes. The former state may comprise of nodes from all the generations forming self-organized cluster or nodes from few generations yielding driven clusters depending upon on the parity of heterogeneous delay values. Furthermore, heterogeneity in delays leads to the lag synchronization between the siblings lying on the boundary by destroying the exact synchronization among them. The time lag being equal to the difference in the delay values. The Lyapunov function analysis sheds light on the destruction of the exact synchrony among the last generation nodes. To the end we discuss the relevance of our results with respect to their applications in the family business as well as in understanding the occurrence of genetic diseases.
Characterization of superconducting nanowire single-photon detector with artificial constrictions
Authors: Zhang Ling , You Lixing , Liu Dengkuan , Zhang Weijun , Zhang Lu , Liu Xiaoyu , Wu Junjie , He Yuhao , Lv Chaolin , Wang Zhen , Xie Xiaoming
Published: June 2014

Statistical studies on the performance of different superconducting nanowire single-photon detectors (SNSPDs) on one chip suggested that random constrictions existed in the nanowire that were barely registered by scanning electron microscopy. With the aid of advanced e-beam lithography, artificial geometric constrictions were fabricated on SNSPDs as well as single nanowires. In this way, we studied the influence of artificial constrictions on SNSPDs in a straight forward manner. By introducing artificial constrictions with different wire widths in single nanowires, we concluded that the dark counts of SNSPDs originate from a single constriction. Further introducing artificial constrictions in SNSPDs, we studied the relationship between detection efficiency and kinetic inductance and the bias current, confirming the hypothesis that constrictions exist in SNSPDs.
Use of External Radical Sources in Flash Vacuum Pyrolysis to Facilitate Cyclodehydrogenation Reactions in Polycyclic Aromatic Hydrocarbons
Authors: Amick Aaron W. , Martin Sara E.
Published: June 2014

A new process to facilitate the cyclodehydrogenation of polycyclic aromatic hydrocarbons (PAHs) in flash vacuum pyrolysis (FVP) using an external radical source is described. Using hexanes as an external radical source the conversion of various PAHs to their cyclodehydrogenated products is vastly increased. Various other volatile organic compounds were also examined to determine their ability to act as external radical sources in FVP.
Speciation mapping of environmental samples using XANES imaging
Authors: Etschmann Barbara E. , Donner Erica , Brugger Joël , Howard Daryl L. , de Jonge Martin D. , Paterson David , Naidu Ravi , Scheckel Kirk G. , Ryan Chris G. , Lombi Enzo
Published: June 2014

Environmental context
Recently developed fast fluorescence detectors have opened the way to the development of element speciation mapping, i.e. X-ray absorption near edge spectroscopy (XANES) imaging, of environmental samples. This technique is potentially very informative but is also highly data intensive. Here, we used XANES imaging to explore the distribution of Cu species in biosolid materials, destined for agricultural use, as this is of importance in relation to the bioavailability and potential toxicity of this metal.

Abstract
Fast X-ray detectors with large solid angles and high dynamic ranges open the door to XANES imaging, in which millions of spectra are collected to image the speciation of metals at micrometre resolution, over areas up to several square centimetres. This paper explores how such multispectral datasets can be analysed in order to provide further insights into the distribution of Cu species in fresh and stockpiled biosolids. The approach demonstrated uses Principal Components Analysis to extract the ‘significant’ spectral information from the XANES maps, followed by cluster analysis to locate regions of contrasting spectral signatures. Following this model-free analysis, pixel-by-pixel linear combination fits are used to provide a direct link between bulk and imaging XANES spectroscopy. The results indicate that both the speciation and distribution of Cu species are significantly affected by ageing. The majority of heterogeneously distributed micrometre-sized Cu sulfide particles present in fresh biosolids disappear during the oxidative stockpiling process. In aged biosolids most of the Cu is homogeneously redistributed on organic matter suggesting that Cu mobility is temporarily increased during this redistribution process. This manuscript demonstrates how large XANES imaging datasets could be analysed and used to gain a deep understanding of metal speciation in environmental samples.
Nanoparticle core properties affect attachment of macromolecule-coated nanoparticles to silica surfaces
Authors: Hotze Ernest M. , Louie Stacey M. , Lin Shihong , Wiesner Mark R. , Lowry Gregory V.
Published: June 2014

Environmental context
The increasing use of engineered nanoparticles has led to concerns over potential exposure to these novel materials. Predictions of nanoparticle transport in the environment and exposure risks could be simplified if all nanoparticles showed similar deposition behaviour when coated with macromolecules used in production or encountered in the environment. We show, however, that each nanoparticle in this study exhibited distinct deposition behaviour even when coated, and hence risk assessments may need to be specifically tailored to each type of nanoparticle.

Abstract
Transport, toxicity, and therefore risks of engineered nanoparticles (ENPs) are unquestionably tied to interactions between those particles and surfaces. In this study, we proposed the simple and untested hypothesis that coating type can be the predominant factor affecting attachment of ENPs to silica surfaces across a range of ENP and coating types, effectively masking the contribution of the particle core to deposition behaviour. To test this hypothesis, TiO2, Ag0 and C60 nanoparticles with either no coating or one of three types of adsorbed macromolecules (poly(acrylic acid), humic acid and bovine serum albumin) were prepared. The particle size and adsorbed layer thicknesses were characterised using dynamic light scattering and soft particle electrokinetic modelling. The attachment efficiencies of the nanoparticles to silica surfaces (glass beads) were measured in column experiments and compared with predictions from a semi-empirical correlation between attachment efficiency and coated particle properties that included particle size and layer thickness. For the nanoparticles and adsorbed macromolecules in this study, the attachment efficiencies could not be explained solely by the coating type. Therefore, the hypothesis that adsorbed macromolecules will mask the particle core and control attachment was disproved, and information on the properties of both the nanoparticle surface (e.g. charge and hydrophobicity) and adsorbed macromolecule (e.g. molecular weight, charge density extended layer thickness) will be required to explain or predict interactions of coated nanoparticles with surfaces in the environment.
Development and validation of a shipboard system for measuring high-resolution vertical profiles of aqueous dimethylsulfide concentrations using chemical ionisation mass spectrometry
Authors: Royer Sarah-Jeanne , Galí Martí , Saltzman Eric S. , McCormick Cyril A. , Bell Thomas G. , Simó Rafel
Published: June 2014

Environmental context
Dimethylsulfide, a trace gas produced by oceanic plankton, is a key chemical species in the global cycles of sulfur and aerosols, with implications that span marine ecology to climate regulation. Knowledge of what governs dimethylsulfide production in the surface ocean depends on our ability to measure concentration changes over time and depth. We describe a sampling and analytical system that provides continuous shipboard measurements of dimethylsulfide concentrations in high-resolution vertical profiles.

Abstract
A sampling and analytical system has been developed for shipboard measurements of high-resolution vertical profiles of the marine trace gas dimethylsulfide (DMS). The system consists of a tube attached to a conductivity–temperature–depth (CTD) probe with a peristaltic pump on deck that delivers seawater to a membrane equilibrator and atmospheric pressure chemical ionisation mass spectrometer (Eq-APCIMS). This allows profiling of DMS concentrations to a depth of 50m, with a depth resolution of 1.3–2m and a detection limit of nearly 0.1nmolL–1. The seawater is also plumbed to allow parallel operation of additional continuous instruments, and simultaneous collection of discrete samples for complementary analyses. A valve alternates delivery of seawater from the vertical profiler and the ship’s underway intake, thereby providing high-resolution measurements in both the vertical and horizontal dimensions. Tests conducted on various cruises in the Mediterranean Sea, Atlantic, Indian, and Pacific Oceans show good agreement between the Eq-APCIMS measurements and purge and trap gas chromatography with flame photometric detection (GC-FPD) and demonstrate that the delivery of seawater from the underway pump did not significantly affect endogenous DMS concentrations. Combining the continuous flow DMS analysis with high-frequency hydrographic, optical, biological and meteorological measurements will greatly improve the spatial–temporal resolution of seagoing measurements and improve our understanding of DMS cycling.
Evaluating the prevention of premature cessation of exclusive breastfeeding in the general practice setting during the scheduled child immunisation consultation: a pilot study
Authors: Ayton Jennifer , Howes Faline , Hansen Emily , Nelson Mark
Published: June 2014

The purpose of this study was to test and evaluate the feasibility and clinical acceptability of the use of an infant feeding data collection tool during the scheduled childhood immunisation consultation, and to explore the appropriateness of this consultation as a site for a future intervention aiming to increase exclusive breastfeeding through the provision of advice and support to mothers. This descriptive exploratory (quantitative and qualitative) study used purposeful sampling to enrol five general practices in Hobart, Tasmania. General practitioners (GPs) and practice nurses (PNs) trialled and evaluated a paper-based data collection tool over a 6-week period from May through to June 2011. Twenty-two (13 GPs; 2 GP registrars and 7 PNs) participants trialled and evaluated the data collection tool (n = 54). From the evaluation questionnaire, field notes and informal interviews (n = 7), six conceptual headings emerged: setting; time pressures; resources and collaboration; mothers need to talk; professional exclusion; and lack of collaboration. The scheduled childhood immunisation consultation provides an opportunity for mothers and primary health practitioners to talk briefly about infant feeding and for the collection of infant feeding data. However, the immunisation consultation is not well suited to a breastfeeding support intervention as it is already very busy focusing on immunisation issues. Consideration should be given to the evaluation of a dedicated general practice/primary health ‘infant feeding’ consultation.
Effects of salts on the interaction of 8-anilinonaphthalene 1-sulphonate and thermolysin
Authors: Samukange Vimbai , Kamo Masayuki , Yasukawa Kiyoshi , Inouye Kuniyo
Published: June 2014

Neutral salts activate and stabilize thermolysin. In this study, to explore the mechanism, we analyzed the interaction of 8-anilinonaphthalene 1-sulphonate (ANS) and thermolysin by ANS fluorescence. At pH 7.5, the fluorescence of ANS increased and blue-shifted with increasing concentrations (0–2.0 μM) of thermolysin, indicating that the anilinonaphthalene group of ANS binds with thermolysin through hydrophobic interaction. ANS did not alter thermolysin activity. The dissociation constants (Kd) of the complex between ANS and thermolysin was 33 ± 2 μM at 0 M NaCl at pH 7.5, decreased with increasing NaCl concentrations, and reached 9 ± 3 μM at 4 M NaCl. The Kd values were not varied (31−34 μM) in a pH range of 5.5−8.5. This suggests that at high NaCl concentrations, Na+ and/or Cl– ions bind with thermolysin and affect the binding of ANS with thermolysin. Our results also suggest that the activation and stabilization of thermolysin by NaCl are partially brought about by the binding of Na+ and/or Cl– ions with thermolysin.
Cartography as a Tool of Colonization: Sir Humphrey Gilbert’s 1583 Voyage to North America*
Authors: Probasco Nate
Published: June 2014

An analysis of Sir Humphrey Gilbert’s 1583 expedition to North America, which was England’s first attempt at colonization beyond Britain, shows that the nation’s earliest expansionists perceived the significance of maps in supporting colonization. Gilbert recruited several specialists, including John Dee and Richard Hakluyt, who expended considerable time and resources conducting research for their maps and drawing up plans to survey the colony. A thorough examination of Gilbert’s sea chart and terrestrial maps clarifies how his circle used them to promote the expedition, to guide it to North America, and to assert their control over the territory. Scholars often depict early modern English colonizers as having little interest in cartographic materials, but Gilbert and his supporters proved that maps served a number of vital functions in preparing and executing a colonizing expedition.
A stably contractible 𝐶*-algebra which is not contractible
Authors: Dadarlat Marius
Published: June 2014

We exhibit a separable commutative

C
∗

C^\ast

-algebra

A
A

such that

A
⊗

K

A\otimes \mathcal {K}

is homotopy equivalent to zero, without

M
n

(
A
)

M_n(A)

being so for any

n
≥
1

n\geq 1

.
Osmotic induction improves batch marking of larval fish otoliths with enriched stable isotopes
Authors: de Braux Emmanuel , Warren-Myers Fletcher , Dempster Tim , Fjelldal Per Gunnar , Hansen Tom , Swearer Stephen E.
Published: June 2014

Otolith marking with enriched stable isotopes via immersion is a recent method of batch marking larval fish for a range of research and industrial applications. However, current immersion times and isotope concentrations required to successfully mark an otolith limit the utility of this technique. Osmotic induction improves incorporation and reduces immersion time for some chemical markers, but its effects on isotope incorporation into otoliths are unknown. Here, we tested the effects of osmotic induction over a range of different isotope concentrations and immersion times on relative mark success and strength for 26Mg:24Mg, 86Sr:88Sr and 137Ba:138Ba on Atlantic salmon (Salmo salar) larvae. 71% and 100% mark success were achieved after 1 h of immersion for 86Sr (75 µg L−1) and 137Ba (30 µg L−1) isotopes, respectively. Compared with conventional immersion, osmotic induction improved overall mark strength for 86Sr and 137Ba isotopes by 26–116%, although this effect was only observed after 12 h of immersion and predominately for 86Sr. The results demonstrate that osmotic induction reduces immersion times and the concentrations of isotope required to achieve successful marks. Osmotically induced isotope labels via larval immersion may prove a rapid and cost-effective way of batch marking fish larvae across a range of potential applications.