bluuebunny/crossref_metadata_2025 huggingface dataset:
Boronate microparticle-supported nano-palladium and nano-gold catalysts for chemoselective hydrogenation of cinnamaldehyde in environmentally preferable solvents
Authors: Fujiwara Seika , Takanashi Naoto , Nishiyabu Ryuhei , Kubo Yuji
Published: April 2014

An efficient chemoselective hydrogenation of cinnamaldehyde over boronate microparticle-supported nano-palladium and nano-gold catalysts under environmentally benign conditions is reported.
Highly sensitive and multispectral responsive phototransistor using tungsten-doped VO2 nanowires
Authors: Lu Junpeng , Liu Hongwei , Deng Suzi , Zheng Minrui , Wang Yinghui , van Kan Jeroen A. , Tang Sing Hai , Zhang Xinhai , Sow Chorng Haur , Mhaisalkar Subodh G.
Published: April 2014

A superior phototransistor was fabricated from W-doped VO2 nanowires. The device exhibited ultrafast photoresponse, high responsivity and broadband response.
Palladium-catalyzed reductive cleavage of tosylated arenes using isopropanol as the mild reducing agent
Authors: Chow Wing Kin , So Chau Ming , Lau Chak Po , Kwong Fuk Yee
Published: April 2014

The reduction (deuteration) of oxygenated arenes can be achieved by Pd/CM-phos catalyst system via a tosylation pathway.
Time-resolved surface rearrangements of polymer films monitored by dynamic recovery contact angle (DRCA)
Authors: Esteves A. Catarina C. , Günbas I. Doğan , van Riel Jan M. , Noordover Bart A. J. , de With Gijsbertus , van Benthem Rolf A. T. M.
Published: April 2014

The time-frames involved in surface rearrangements of polymer films are investigated by Dynamic Recovery Contact Angle (DRCA) through a simple, non-invasive and reconstructive approach.
Construction of chiral quaternary carbon center via catalytic asymmetric aza-Henry reaction with α-substituted nitroacetates
Authors: Li Minghua , Ji Nan , Lan Ting , He Wei , Liu Rui
Published: April 2014

The catalytic enantioselective aza-Henry reaction of N-Boc aldimines 2 and 2-nitropropionic acid ethyl ester 3 in mixed solvents were catalyzed by cinchona quaternary ammonium salts to form a new quaternary carbon center. High yields (up to 90%), excellent enantioselectivities (up to 99% ee) and diastereoselectivities ratio (up to 22 : 1) were successfully obtained with mild conditions.
2,5-Dimethoxy 2,5-dihydrofuran crosslinked chitosan fibers enhance bone regeneration in rabbit femur defects
Authors: Ghosh Paulomi , Rameshbabu Arun Prabhu , Dogra Nantu , Dhara Santanu
Published: April 2014

Chitosan fibers were fabricated via pH induced neutralization and precipitation in a 5 w/v% NaOH bath.
Biocompatible graphene oxide as a folate receptor-targeting drug delivery system for the controlled release of anti-cancer drugs
Authors: Zhao Xubo , Liu Peng
Published: April 2014

A novel graphene oxide (GO)-based nanocarrier has been designed for the targeting and pH-responsive controlled release of anti-cancer drugs.
Polarization-selective excitation of plasmonic resonances in silver nanocube random arrays by optical fiber cladding mode evanescent fields
Authors: Ianoul Anatoli , Robson Mitchell , Pripotnev Vladislav , Albert Jacques
Published: April 2014

Silver nanocubes provide polarization resolved enhancement of the evanescent waves of optical fiber cladding modes.
Applications of ytterbium in inverted organic photovoltaic cells as high-performance and stable electron transport layers
Authors: Kim Gyu Min , Oh Il Soo , Lee Ae Na , Oh Se Young
Published: April 2014

The electron transport layer (ETL) increases the power conversion efficiency (PCE) in organic photovoltaic cells (OPVs) by promoting the formation of ohmic contact between the active layer and the cathode metal.
Large area multi-stacked lithium-ion batteries for flexible and rollable applications
Authors: Kim Joo-Seong , Lee Yong-Hee , Lee Inhwa , Kim Taek-Soo , Ryou Myung-Hyun , Choi Jang Wook
Published: April 2014

Large area multi-stacked lithium-ion battery modules are developed for flexible and rollable applications by employing conductive textiles.
Effects of the mesostructural order on the electrochemical performance of hierarchical micro–mesoporous carbons
Authors: Enterría M. , Castro-Muñiz A. , Suárez-García F. , Martínez-Alonso A. , Tascón J. M. D. , Kyotani T.
Published: April 2014

Hierarchical ordered porous carbons show a better behavior as electric double layer capacitors (EDLCs) than disordered carbons especially at high rates thanks to their unique architectural design.
Silicon/graphene based nanocomposite anode: large-scale production and stable high capacity for lithium ion batteries
Authors: Hu Renzong , Sun Wei , Chen Yulong , Zeng Meiqin , Zhu Min
Published: April 2014

Plasma-assisted milled Si/graphene nanocomposite anode delivers high capacity and good cycleability in half and full cells using a LiMn2O4 cathode.
Composites of boron-doped carbon nanosheets and iron oxide nanoneedles: fabrication and lithium ion storage performance
Authors: Yang Yongqiang , Zhang Jianan , Wu Xiaochen , Fu Yongsheng , Wu Haixia , Guo Shouwu
Published: April 2014

Composites of boron-doped carbon nanosheets/Fe3O4 nanoneedles show a large specific capacity, high rate capability, and excellent cycling stability as an anode for lithium ion batteries.
An aqueous electrolyte rechargeable Li-ion/polysulfide battery
Authors: Demir-Cakan Rezan , Morcrette Mathieu , Leriche Jean-Bernard , Tarascon Jean-Marie
Published: April 2014

In spite of great research efforts on Li–S batteries in aprotic organic electrolytes, there have been very few studies showing the potential application of this system in aqueous electrolyte. Herein, we explore this option and report on a cheaper and safer new aqueous system coupling a well-known cathode material in Li-ion batteries (i.e. LiMn2O4) with a dissolved polysulfide anode.
Facile preparation of hierarchical Nb2O5 microspheres with photocatalytic activities and electrochemical properties
Authors: Guo Sheng-qi , Zhang Xiao , Zhou Zhen , Gao Guan-dao , Liu Lu
Published: April 2014

Hierarchical flower-like Nb2O5 microspheres have been prepared via a facile hydrothermal approach without any additives.
Fe2O3/Cu2O heterostructured nanocrystals
Authors: Mirtchev Peter , Liao Kristine , Jaluague Elizabeth , Qiao Qiao , Tian Yao , Varela Maria , Burch Kenneth S. , Pennycook Stephen J. , Perovic Doug D. , Ozin Geoffrey
Published: April 2014

We report the synthesis of colloidal γ-Fe2O3/Cu2O hetero-nanocrystals (HNCs) using a solution-phase seeded-growth approach. The structural and electronic properties of these materials are investigated by HRTEM and photoelectron spectroscopy. A type II band alignment was found between the p-Cu2O and n-Fe2O3 domains making the particles potentially attractive candidates for applications in solar energy conversion.
Aggregation inhibition for graphene oxide nanosheets in polyelectrolyte solutions and assembly of nanocapsules with graphene oxide nanosheets as template
Authors: Xin Jing , Zhang Renjie , Hou Wanguo
Published: April 2014

A strategy for inhibiting aggregation of graphene oxide (GO) nanosheets is proposed in this work, which is important to understand the physical chemistry of the stability of GO and related factors.
Enhanced light–matter interaction of graphene–gold nanoparticle hybrid films for high-performance SERS detection
Authors: Du Yuanxin , Zhao Yuan , Qu Yan , Chen Chia-Hao , Chen Chieh-Ming , Chuang Cheng-Hao , Zhu Yanwu
Published: April 2014

We demonstrate enhanced light–matter interactions in graphene–Au nanoparticle hybrid films and the application for high-quality SERS detection.
Role of AMACR (α-methylacyl-CoA racemase) and MFE-1 (peroxisomal multifunctional enzyme-1) in bile acid synthesis in mice
Authors: Autio Kaija J. , Schmitz Werner , Nair Remya R. , Selkälä Eija M. , Sormunen Raija T. , Miinalainen Ilkka J. , Crick Peter J. , Wang Yuqin , Griffiths William J. , Reddy Janardan K. , Baes Myriam , Hiltunen J. Kalervo
Published: April 2014

Cholesterol is catabolized to bile acids by peroxisomal β-oxidation in which the side chain of C27-bile acid intermediates is shortened by three carbon atoms to form mature C24-bile acids. Knockout mouse models deficient in AMACR (α-methylacyl-CoA racemase) or MFE-2 (peroxisomal multifunctional enzyme type 2), in which this β-oxidation pathway is prevented, display a residual C24-bile acid pool which, although greatly reduced, implies the existence of alternative pathways of bile acid synthesis. One alternative pathway could involve Mfe-1 (peroxisomal multifunctional enzyme type 1) either with or without Amacr. To test this hypothesis, we generated a double knockout mouse model lacking both Amacr and Mfe-1 activities and studied the bile acid profiles in wild-type, Mfe-1 and Amacr single knockout mouse line and Mfe-1 and Amacr double knockout mouse lines. The total bile acid pool was decreased in Mfe-1−/− mice compared with wild-type and the levels of mature C24-bile acids were reduced in the double knockout mice when compared with Amacr-deficient mice. These results indicate that Mfe-1 can contribute to the synthesis of mature bile acids in both Amacr-dependent and Amacr-independent pathways.
Design, development, and acceleration trials of radio-frequency quadrupole
Authors: Rao S. V. L. S. , Jain Piyush , Pande Rajni , Roy Shweta , Mathew Jose V. , Kumar Rajesh , Pande Manjiri , Krishnagopal S. , Gupta S. K. , Singh P.
Published: April 2014

A deuteron radio frequency quadrupole (RFQ) accelerator has been designed, fabricated, and tested at BARC, which will be used for neutron generation. The RFQ operates at a frequency of 350 MHz and needs an inter-vane voltage of 44 kV to accelerate the deuteron beam to 400 keV within a length of 1.03 m. The error analysis shows that the offset of two opposite vanes in the same direction by 100 μm leads to a change in resonant frequency by 1.3 MHz and a significant change of fields in the quadrants (∼±40% with respect to average field). From the 3D analysis, we have observed that the unwanted dipole mode frequencies are very near to the quadrupole mode frequency which will make structure sensitive to the perturbations. In order to move the dipole modes away from the quadrupole modes, we have used the dipole stabilizer rods. The 5 wire transmission line theory was used to study the perturbative analysis of the RFQ and based on this a computer program has been written to tune the cavity to get required field distribution. Based on these studies, a 1.03 m long RFQ made of OFE copper has been fabricated and tested. Even though the RFQ was designed for deuteron (D+) beam, we tested it by accelerating both the proton (H+) and D+ beams. The RFQ was operated in pulsed mode and accelerated both H+ and D+ beams to designed values of 200 and 400 keV, respectively. The measured parameters are in good agreement with the designed values validating our simulations and fabrication processes. In this paper, simulations, RF measurements, and beam commissioning results are presented.
Fabrication of highly spin-polarized Co2FeAl0.5Si0.5 thin-films
Authors: Vahidi M. , Gifford J. A. , Zhang S. K. , Krishnamurthy S. , Yu Z. G. , Yu L. , Huang M. , Youngbull C. , Chen T. Y. , Newman N.
Published: April 2014

Ferromagnetic Heusler Co2FeAl0.5Si0.5 epitaxial thin-films have been fabricated in the L21 structure with saturation magnetizations over 1200 emu/cm3. Andreev reflection measurements show that the spin polarization is as high as 80% in samples sputtered on unheated MgO (100) substrates and annealed at high temperatures. However, the spin polarization is considerably smaller in samples deposited on heated substrates.
A comparison of four direct geometry time-of-flight spectrometers at the Spallation Neutron Source
Authors: Stone M. B. , Niedziela J. L. , Abernathy D. L. , DeBeer-Schmitt L. , Ehlers G. , Garlea O. , Granroth G. E. , Graves-Brook M. , Kolesnikov A. I. , Podlesnyak A. , Winn B.
Published: April 2014

The Spallation Neutron Source at Oak Ridge National Laboratory now hosts four direct geometry time-of-flight chopper spectrometers. These instruments cover a range of wave-vector and energy transfer space with varying degrees of neutron flux and resolution. The regions of reciprocal and energy space available to measure at these instruments are not exclusive and overlap significantly. We present a direct comparison of the capabilities of this instrumentation, conducted by data mining the instrument usage histories, and specific scanning regimes. In addition, one of the common science missions for these instruments is the study of magnetic excitations in condensed matter systems. We have measured the powder averaged spin wave spectra in one particular sample using each of these instruments, and use these data in our comparisons.
Electroforming-free resistive switching memory effect in transparent p-type tin monoxide
Authors: Hota M. K. , Caraveo-Frescas J. A. , McLachlan M. A. , Alshareef H. N.
Published: April 2014

We report reproducible low bias bipolar resistive switching behavior in p-type SnO thin film devices without extra electroforming steps. The experimental results show a stable resistance ratio of more than 100 times, switching cycling performance up to 180 cycles, and data retention of more than 103 s. The conduction mechanism varied depending on the applied voltage range and resistance state of the device. The memristive switching is shown to originate from a redox phenomenon at the Al/SnO interface, and subsequent formation/rupture of conducting filaments in the bulk of the SnO layer, likely involving oxygen vacancies and Sn interstitials.
Optical and phonon properties of ZnO:CuO mixed nanocomposite
Authors: Udayabhaskar R. , Karthikeyan B.
Published: April 2014

Optical and phonon properties of ZnO:CuO nanocrystals which are prepared through sol-gel method are reported here. From X-ray diffraction studies, observed that Cu doping replaces the Zn and also forms secondary phase. Optical absorption spectral studies shows that the exciton and plasmon related bands of ZnO and CuO phase, respectively. Fluorescence studies of the prepared samples shows that green emission from ZnO is completely depleted and the same is attributed to CuO Plasmon. Raman spectral studies reveal that secondary phase (impurity) induced profile changes in 1LO and E2High modes. Asymmetry in peak shape is analyzed using Fano profile with the combination of Lorentzian profile. Moreover, the monotonic increase of Fano factor and full width at half maxima is hopefully attributed to the continuum arises by the plasmons of Cu-O phase in ZnO nanosystem.
Spin transfer torque generated magnetic droplet solitons (invited)
Authors: Chung S. , Mohseni S. M. , Sani S. R. , Iacocca E. , Dumas R. K. , Anh Nguyen T. N. , Pogoryelov Ye. , Muduli P. K. , Eklund A. , Hoefer M. , Åkerman J.
Published: April 2014

We present recent experimental and numerical advancements in the understanding of spin transfer torque generated magnetic droplet solitons. The experimental work focuses on nano-contact spin torque oscillators (NC-STOs) based on orthogonal (pseudo) spin valves where the Co fixed layer has an easy-plane anisotropy, and the [Co/Ni] free layer has a strong perpendicular magnetic anisotropy. The NC-STO resistance and microwave signal generation are measured simultaneously as a function of drive current and applied perpendicular magnetic field. Both exhibit dramatic transitions at a certain current dependent critical field value, where the microwave frequency drops 10 GHz, modulation sidebands appear, and the resistance exhibits a jump, while the magnetoresistance changes sign. We interpret these observations as the nucleation of a magnetic droplet soliton with a large fraction of its magnetization processing with an angle greater than 90°, i.e., around a direction opposite that of the applied field. This interpretation is corroborated by numerical simulations. When the field is further increased, we find that the droplet eventually collapses under the pressure from the Zeeman energy.
Can the ring polymer molecular dynamics method be interpreted as real time quantum dynamics?
Authors: Jang Seogjoo , Sinitskiy Anton V. , Voth Gregory A.
Published: April 2014

The ring polymer molecular dynamics (RPMD) method has gained popularity in recent years as a simple approximation for calculating real time quantum correlation functions in condensed media. However, the extent to which RPMD captures real dynamical quantum effects and why it fails under certain situations have not been clearly understood. Addressing this issue has been difficult in the absence of a genuine justification for the RPMD algorithm starting from the quantum Liouville equation. To this end, a new and exact path integral formalism for the calculation of real time quantum correlation functions is presented in this work, which can serve as a rigorous foundation for the analysis of the RPMD method as well as providing an alternative derivation of the well established centroid molecular dynamics method. The new formalism utilizes the cyclic symmetry of the imaginary time path integral in the most general sense and enables the expression of Kubo-transformed quantum time correlation functions as that of physical observables pre-averaged over the imaginary time path. Upon filtering with a centroid constraint function, the formulation results in the centroid dynamics formalism. Upon filtering with the position representation of the imaginary time path integral, we obtain an exact quantum dynamics formalism involving the same variables as the RPMD method. The analysis of the RPMD approximation based on this approach clarifies that an explicit quantum dynamical justification does not exist for the use of the ring polymer harmonic potential term (imaginary time kinetic energy) as implemented in the RPMD method. It is analyzed why this can cause substantial errors in nonlinear correlation functions of harmonic oscillators. Such errors can be significant for general correlation functions of anharmonic systems. We also demonstrate that the short time accuracy of the exact path integral limit of RPMD is of lower order than those for finite discretization of path. The present quantum dynamics formulation also serves as the basis for developing new quantum dynamical methods that utilize the cyclic nature of the imaginary time path integral.
Fusion-neutron-yield, activation measurements at the Z accelerator: Design, analysis, and sensitivity
Authors: Hahn K. D. , Cooper G. W. , Ruiz C. L. , Fehl D. L. , Chandler G. A. , Knapp P. F. , Leeper R. J. , Nelson A. J. , Smelser R. M. , Torres J. A.
Published: April 2014

We present a general methodology to determine the diagnostic sensitivity that is directly applicable to neutron-activation diagnostics fielded on a wide variety of neutron-producing experiments, which include inertial-confinement fusion (ICF), dense plasma focus, and ion beam-driven concepts. This approach includes a combination of several effects: (1) non-isotropic neutron emission; (2) the 1/r2 decrease in neutron fluence in the activation material; (3) the spatially distributed neutron scattering, attenuation, and energy losses due to the fielding environment and activation material itself; and (4) temporally varying neutron emission. As an example, we describe the copper-activation diagnostic used to measure secondary deuterium-tritium fusion-neutron yields on ICF experiments conducted on the pulsed-power Z Accelerator at Sandia National Laboratories. Using this methodology along with results from absolute calibrations and Monte Carlo simulations, we find that for the diagnostic configuration on Z, the diagnostic sensitivity is 0.037% ± 17% counts/neutron per cm2 and is ∼ 40% less sensitive than it would be in an ideal geometry due to neutron attenuation, scattering, and energy-loss effects.
A tunable line optical tweezers instrument with nanometer spatial resolution
Authors: Rogers W. Benjamin , Crocker John C.
Published: April 2014

We describe a simple scanning-line optical tweezers instrument for measuring pair interactions between micrometer-sized colloidal particles. Our instrument combines a resonant scanning mirror and an acousto-optic modulator. The resonant scanning mirror creates a time-averaged line trap whose effective one-dimensional intensity profile, and corresponding trapping potential energy landscape can be programmed using the acousto-optic modulator. We demonstrate control over the confining potential by designing and measuring a family of one-dimensional harmonic traps. By adjusting the spring constant, we balance scattering-induced repulsive forces between a pair of trapped particles, creating a flat potential near contact that facilitates interaction measurements. We also develop a simple method for extracting the out-of-plane motion of trapped particles from their relative brightness, allowing us to resolve their relative separation to roughly 1 nm.
Improved spectral data unfolding for radiochromic film imaging spectroscopy of laser-accelerated proton beams
Authors: Schollmeier M. , Geissel M. , Sefkow A. B. , Flippo K. A.
Published: April 2014

An improved method to unfold the space-resolved proton energy distribution function of laser-accelerated proton beams using a layered, radiochromic film (RCF) detector stack has been developed. The method takes into account the reduced RCF response near the Bragg peak due to a high linear energy transfer (LET). This LET dependence of the active RCF layer has been measured, and published data have been re-interpreted to find a nonlinear saturation scaling of the RCF response with stopping power. Accounting for the LET effect increased the integrated particle yield by 25% after data unfolding. An iterative, analytical, space-resolved deconvolution of the RCF response functions from the measured dose was developed that does not rely on fitting. After the particle number unfold, three-dimensional interpolation is performed to determine the spatial proton beam distribution for proton energies in-between the RCF data points. Here, image morphing has been implemented as a novel interpolation method that takes into account the energy-dependent, changing beam topology.
A field-programmable-gate-array based time digitizer for the time-of-flight mass spectrometry
Authors: Ye Chunfeng , Zhao Lei , Zhou Zhongyue , Liu Shubin , An Qi
Published: April 2014

The time-of-flight (TOF) mass spectrometry is one of the most widely used techniques to get information about the composition and structure of compounds. The time digitizer, based on time-to-digital conversion, is one of the important parts in modern TOF mass spectrometry, which is often implemented with analog circuitry or application-specific-integrated-circuit (ASIC) devices. However, it is difficult to achieve a high density with the analog approach. Furthermore, ASIC requires a long design cycle and the function cannot be easily revised for different applications. In this work, we present a highly flexible, accurate, yet low-costing design of time digitizer which is based on a field-programmable-gate-array (FPGA) and time interpolation method. Test results indicate that the bin size of this time digitizer is 390 ps with an average standard deviation (about 150 ps). The differential nonlinearity is in the range of −0.10 to +0.05 LSB (least significant bit), and the measurement time range is larger than 107 s. Compared with other techniques, it reduces the system complexity while providing a good flexibility. In addition, this technique can also accommodate one or more STOP pulse measurements for each START pulse reference, enabling measurement of multiple times-of-flight with a common start trigger. Besides, a time stamp is recorded for each input pulse, rendering this time digitizer versatile in other applications. Moreover, because of the programmable characteristic of a FPGA, more functions can be integrated in the time digitizer, such as a trigger function, data transfer interface; the parameters such as the number of the channels. The measurement range can also be modified according to different requirements.
Dual-polarity GaN micropillars grown by metalorganic vapour phase epitaxy: Cross-correlation between structural and optical properties
Authors: Coulon P. M. , Mexis M. , Teisseire M. , Jublot M. , Vennéguès P. , Leroux M. , Zuniga-Perez J.
Published: April 2014

Self-assembled catalyst-free GaN micropillars grown on (0001) sapphire substrates by metal organic vapor phase epitaxy are investigated. Transmission electron microscopy, as well as KOH etching, shows the systematic presence of two domains of opposite polarity within each single micropillar. The analysis of the initial growth stages indicates that such double polarity originates at the micropillar/substrate interface, i.e., during the micropillar nucleation, and it propagates along the micropillar. Furthermore, dislocations are also generated at the wire/substrate interface, but bend after several hundreds of nanometers. This leads to micropillars several tens of micrometers in length that are dislocation-free. Spatially resolved cathodoluminescence and microphotoluminescence show large differences in the optical properties of each polarity domain, suggesting unequal impurity/dopant/vacancy incorporation depending on the polarity.
A diabatic representation of the two lowest electronic states of Li3
Authors: Ghassemi Elham Nour , Larson Jonas , Larson Åsa
Published: April 2014

Using the Multi-Reference Configuration Interaction method, the adiabatic potential energy surfaces of Li3 are computed. The two lowest electronic states are bound and exhibit a conical intersection. By fitting the calculated potential energy surfaces to the cubic E ⊗ ɛ Jahn-Teller model we extract the effective Jahn-Teller parameters corresponding to Li3. These are used to set up the transformation matrix which transforms from the adiabatic to a diabatic representation. This diabatization method gives a Hamiltonian for Li3 which is free from singular non-adiabatic couplings and should be accurate for large internuclear distances, and it thereby allows for bound dynamics in the vicinity of the conical intersection to be explored.
Vorticity amplification near the stagnation point of landing gear wheels
Authors: Feltham G. , Ekmekci A.
Published: April 2014

The vicinity near the forward stagnation point of landing-gear wheels has been found to support a mechanism for oncoming streams of weak vorticity to collect, grow, and amplify into discrete large-scale vortical structures that then shed with a distinct periodicity. To the authors’ knowledge, such a flow phenomenon has never been reported before for landing gear wheels, which are in essence finite (three-dimensional) cylinders. To gain further insight into this phenomenon, a detailed experimental study has been undertaken employing the hydrogen bubble visualization and Particle Image Velocimetry techniques. A very thin platinum wire, similar to those used in hydrogen bubble visualization applications, was placed upstream of the wheel model to produce two streams of weak vorticity (with opposite sign) that convected toward the model. As the vorticity streams enter the stagnation region of the wheels, significant flow deceleration and vorticity stretching act to collect, grow, and amplify the incoming vorticity streams into large-scale vortical structures. Experiments were performed at a fixed Reynolds number, with a value of 32 500 when defined based on the diameter of the wheel and a value of 21 based on the diameter of the vorticity-generating upstream wire. First, to establish a baseline, the natural flow field (without the presence of an upstream wire) was characterized, where experimentally determined values for the stagnation boundary-layer thickness and the velocity profile along the stagnation streamline were both found to agree with the values provided in the literature for two-dimensional cylinders. Subsequently, the dynamics of vorticity collection, growth, amplification, and shedding were studied. The size, stand-off distance and the shedding frequency of the vortical structures forming near the stagnation region were all found to strongly depend on the impingement location of the inbound vorticity on the wheel. A simple relationship between the non-dimensional characteristic size and the non-dimensional shedding frequency was found to hold over the entire range of locations where vorticity amplification and shedding were observed. Penetration of the vortical structures into the stagnation boundary layer was observed for specific locations of inbound vorticity impingement.
Note: Application of a pixel-array area detector to simultaneous single crystal x-ray diffraction and x-ray absorption spectroscopy measurements
Authors: Sun Cheng-Jun , Zhang Bangmin , Brewe Dale L. , Chen Jing-Sheng , Chow G. M. , Venkatesan T. , Heald Steve M.
Published: April 2014

X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr0.67Sr0.33MnO3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam.
Communication: A benchmark-quality, full-dimensional ab initio potential energy surface for Ar-HOCO
Authors: Conte Riccardo , Houston Paul L. , Bowman Joel M.
Published: April 2014

A full-dimensional, global ab initio potential energy surface (PES) for the Ar-HOCO system is presented. The PES consists of a previous intramolecular ab initio PES for HOCO [J. Li, C. Xie, J. Ma, Y. Wang, R. Dawes, D. Xie, J. M. Bowman, and H. Guo, J. Phys. Chem. A 116, 5057 (2012)], plus a new permutationally invariant interaction potential based on fitting 12 432 UCCSD(T)-F12a/aVDZ counterpoise-corrected energies. The latter has a total rms fitting error of about 25 cm−1 for fitted interaction energies up to roughly 12 000 cm−1. Two additional fits are presented. One is a novel very compact permutational invariant representation, which contains terms only involving the Ar-atom distances. The rms fitting error for this fit is 193 cm−1. The other fit is the widely used pairwise one. The pairwise fit to the entire data set has an rms fitting error of 427 cm−1. All of these potentials are used in preliminary classical trajectory calculations of energy transfer with a focus on comparisons with the results using the benchmark potential.
Using giant magneto resistance stripes to efficiently generate direct voltage signals from alternating current excitations
Authors: Kleinlein J. , Ocker B. , Schmidt G.
Published: April 2014

We have developed all metal spintronic devices which convert an alternating current (AC) in-plane current into a direct current (DC) voltage without using external magnetic fields. The devices are based on the modulation of the magnetization of the free magnetic layer in an exchange biased giant magneto resistance nanowire by the current-induced Oersted field. They can be operated at frequencies extending into the GHz range, and the resistance is easily tunable by changing the wire length. The devices can be operated on- or off-resonance. Even off-resonance we demonstrate an efficiency of 0.7 mV DC-output voltage per 1 mW input power. At ferromagnetic resonance, the efficiency is increased and can be as high as 1.8 VW in zero magnetic field. The efficiency of the devices can also be tuned by applying external magnetic fields. The device performance is dominated by the interplay of the Oersted field and the shape anisotropy of the free layer, and for narrow wires the output signal becomes smaller while the possible range of external magnetic fields is extended. The nanowires are easily scalable allowing for higher output voltages or fine tuning of the resistance to match the impedance for RF applications.
Scaling analysis of stock markets
Authors: Bu Luping , Shang Pengjian
Published: April 2014

In this paper, we apply the detrended fluctuation analysis (DFA), local scaling detrended fluctuation analysis (LSDFA), and detrended cross-correlation analysis (DCCA) to investigate correlations of several stock markets. DFA method is for the detection of long-range correlations used in time series. LSDFA method is to show more local properties by using local scale exponents. DCCA method is a developed method to quantify the cross-correlation of two non-stationary time series. We report the results of auto-correlation and cross-correlation behaviors in three western countries and three Chinese stock markets in periods 2004–2006 (before the global financial crisis), 2007–2009 (during the global financial crisis), and 2010–2012 (after the global financial crisis) by using DFA, LSDFA, and DCCA method. The findings are that correlations of stocks are influenced by the economic systems of different countries and the financial crisis. The results indicate that there are stronger auto-correlations in Chinese stocks than western stocks in any period and stronger auto-correlations after the global financial crisis for every stock except Shen Cheng; The LSDFA shows more comprehensive and detailed features than traditional DFA method and the integration of China and the world in economy after the global financial crisis; When it turns to cross-correlations, it shows different properties for six stock markets, while for three Chinese stocks, it reaches the weakest cross-correlations during the global financial crisis.
First principles calculation of the effect of Coulomb collisions in partially ionized gases
Authors: Donkó Z.
Published: April 2014

Coulomb collisions, at appreciable ratios (η) of the electron to the neutral particle density, influence significantly the electron kinetics in particle swarms and in plasmas of gas discharges. This paper introduces a combination of Molecular Dynamics and Monte Carlo simulation techniques, to provide a novel, approximation-free, first principles calculation method for the velocity distribution function of electrons, and related swarm characteristics, at arbitrary η. Simulation results are presented for electrons in argon gas, for density ratios between zero and 10−1, representing the limits of a negligible electron density and an almost complete Maxwellization of the velocity distribution function, respectively.
Kinetics of wet sodium vapor complex plasma
Authors: Mishra S. K. , Sodha M. S.
Published: April 2014

In this paper, we have investigated the kinetics of wet (partially condensed) Sodium vapor, which comprises of electrons, ions, neutral atoms, and Sodium droplets (i) in thermal equilibrium and (ii) when irradiated by light. The formulation includes the balance of charge over the droplets, number balance of the plasma constituents, and energy balance of the electrons. In order to evaluate the droplet charge, a phenomenon for de-charging of the droplets, viz., evaporation of positive Sodium ions from the surface has been considered in addition to electron emission and electron/ion accretion. The analysis has been utilized to evaluate the steady state parameters of such complex plasmas (i) in thermal equilibrium and (ii) when irradiated; the results have been graphically illustrated. As a significant outcome irradiated, Sodium droplets are seen to acquire large positive potential, with consequent enhancement in the electron density.
A microfluidic perfusion platform for cultivation and screening study of motile microalgal cells
Authors: Eu Young-Jae , Park Hye-Sun , Kim Dong-Pyo , Wook Hong Jong
Published: April 2014

Systematic screening of algal cells is getting huge interest due to their capability of producing lipid-based biodiesel. Here, we introduce a new microfluidic platform composed of an array of perfusion chambers designed for long-term cultivation and preliminary screening of motile microalgal cells through loading and releasing of cells to and from the chambers. The chemical environment in each perfusion chamber was independently controlled for 5 days. The effect of nitrogen-depletion on the lipid production, phototaxis behavior in the absence of Ca2+, and cytotoxic effect of herbicide on microalgal cells was successfully monitored and compared with simultaneous control experiments on the platform. The present methodology could be extended to effective screening of algal cells and various cell lines for the production of biodiesel and other useful chemicals.
Cascading metallic gratings for broadband absorption enhancement in ultrathin plasmonic solar cells
Authors: Wen Long , Sun Fuhe , Chen Qin
Published: April 2014

The incorporation of plasmonic nanostructures in the thin-film solar cells (TFSCs) is a promising route to harvest light into the nanoscale active layer. However, the light trapping scheme based on the plasmonic effects intrinsically presents narrow-band resonant enhancement of light absorption. Here we demonstrate that by cascading metal nanogratings with different sizes atop the TFSCs, broadband absorption enhancement can be realized by simultaneously exciting multiple localized surface plasmon resonances and inducing strong coupling between the plasmonic modes and photonic modes. As a proof of concept, we demonstrate of 66.5% in the photocurrent in an ultrathin amorphous silicon TFSC with two-dimensional cascaded gratings over the reference cell without gratings.
Probing the thiol-gold planar interface by spin polarized tunneling
Authors: Zhang Xiaohang , McGill Stephen A. , Xiong Peng , Wang Xiaolei , Zhao Jianhua
Published: April 2014

Reports of induced magnetism at thiol-gold interface have generated considerable recent interest. In these studies, the sample magnetization was generally measured by superconducting quantum interference device magnetometry which has limitation in determining surface and interface magnetism. In this work, we have fabricated planar tunnel junctions incorporating a thiol-gold interface. An observed room temperature humidity effect together with low temperature inelastic electron tunneling spectroscopy confirmed the existence of a thiol-gold interface in the organic-inorganic hybrid heterostructure. Spin polarized tunneling measurements were performed to probe the spin polarization at the thiol-gold interface; however, the obtained spin polarized tunneling spectra indicate no measurable spin polarization at the thiol-gold interface.
Investigation of ionized metal flux in enhanced high power impulse magnetron sputtering discharges
Authors: Stranak Vitezslav , Hubicka Zdenek , Cada Martin , Drache Steffen , Tichy Milan , Hippler Rainer
Published: April 2014

The metal ionized flux fraction and production of double charged metal ions Me2+ of different materials (Al, Cu, Fe, Ti) by High Power Impulse Magnetron Sputtering (HiPIMS) operated with and without a pre-ionization assistance is compared in the paper. The Electron Cyclotron Wave Resonance (ECWR) discharge was employed as the pre-ionization agent providing a seed of charge in the idle time of HiPIMS pulses. A modified grid-free biased quartz crystal microbalance was used to estimate the metal ionized flux fraction ξ. The energy-resolved mass spectrometry served as a complementary method to distinguish particular ion contributions to the total ionized flux onto the substrate. The ratio between densities of doubly Me2+ and singly Me+ charged metal ions was determined. It is shown that ECWR assistance enhances Me2+ production with respect of absorbed rf-power. The ECWR discharge also increases the metal ionized flux fraction of about 30% especially in the region of lower pressures. Further, the suppression of the gas rarefaction effect due to enhanced secondary electron emission of Me2+ was observed.
Band gap engineering strategy via polarization rotation in perovskite ferroelectrics
Authors: Wang Fenggong , Grinberg Ilya , Rappe Andrew M.
Published: April 2014

We propose a strategy to engineer the band gaps of perovskite oxide ferroelectrics, supported by first principles calculations. We find that the band gaps of perovskites can be substantially reduced by as much as 1.2 eV through local rhombohedral-to-tetragonal structural transition. Furthermore, the strong polarization of the rhombohedral perovskite is largely preserved by its tetragonal counterpart. The B-cation off-center displacements and the resulting enhancement of the antibonding character in the conduction band give rise to the wider band gaps of the rhombohedral perovskites. The correlation between the structure, polarization orientation, and electronic structure lays a good foundation for understanding the physics of more complex perovskite solid solutions and provides a route for the design of photovoltaic perovskite ferroelectrics.
High quality factor nanocrystalline diamond micromechanical resonators limited by thermoelastic damping
Authors: Najar Hadi , Chan Mei-Lin , Yang Hsueh-An , Lin Liwei , Cahill David G. , Horsley David A.
Published: April 2014

We demonstrate high quality factor thin-film nanocrystalline diamond micromechanical resonators with quality factors limited by thermoelastic damping. Cantilevers, single-anchored and double-anchored double-ended tuning forks, were fabricated from 2.5 μm thick in-situ boron doped nanocrystalline diamond films deposited using hot filament chemical vapor deposition. Thermal conductivity measured by time-domain thermoreflectance resulted in 24 ± 3 W m−1 K−1 for heat transport through the thickness of the diamond film. The resonant frequencies of the fabricated resonators were 46 kHz–8 MHz and showed a maximum measured Q ≈ 86 000 at fn = 46.849 kHz. The measured Q-factors are shown to be in good agreement with the limit imposed by thermoelastic dissipation calculated using the measured thermal conductivity. The mechanical properties extracted from resonant frequency measurements indicate a Young's elastic modulus of ≈788 GPa, close to that of microcrystalline diamond.
Urban design and health: progress to date and future challenges
Authors: Lowe Melanie , Boulange Claire , Giles‐Corti Billie
Published: April 2014

Over the last 15 years, a growing body of Australian and international evidence has demonstrated that urban design attributes are associated with a range of health outcomes. For example, the location of employment, shops and services, provision of public and active transport infrastructure and access to open space and recreational opportunities are associated with chronic disease risk factors such as physical activity levels, access to healthy food, social connectedness, and air quality. Despite the growing knowledge base, this evidence is not being consistently translated into urban planning policy and practice in Australia. Low‐density neighbourhoods with poor access to public transport, shops and services continue to be developed at a rapid rate in the sprawling outer suburbs of Australian cities. This paper provides an overview of the evidence of the association between the built environment and chronic diseases, highlighting progress and future challenges for health promotion. It argues that health promotion practitioners and researchers need to more closely engage with urban planning practitioners, policymakers and researchers to encourage the creation of healthy urban environments through integrated transport, land use and infrastructure planning. There is also a need for innovative research to evaluate the effectiveness of policy options. This would help evidence to be more effectively translated into policy and practice, making Australia a leader in planning healthy communities.
On the road to prevention: road injury and health promotion
Authors: Stevenson Mark , Thompson Jason
Published: April 2014

Road traffic injuries are already the leading cause of injury mortality and morbidity globally and by 2030 are predicted to be the fifth leading cause of mortality in the world. Australia has seen a dramatic reduction in road deaths and serious injuries since the 1970s and holds an international reputation for road traffic injury prevention due, in part, to its success in pioneering the multidisciplinary and intersectoral approach needed to address this significant issue and by applying an evidence‐led approach to policy development. The paper will discuss Australia's early success in road traffic injury prevention (road safety), particularly the achievements following the implementation of targeted programs that focussed on road user behaviours for which health promotion played a role. The most successful of these programs was the introduction of comprehensive seat belt laws, random breath testing and more recently, strategic speed enforcement programs. Amid an array of significant challenges faced by the transport system in the future, the rapid development in information and communication technologies applied to transport is likely to provide the next generation of road safety benefits. The potential for a semi‐autonomous transport system is likely to provide the next significant decline in road fatalities and serious injuries over the next 2 decades and the role of health promotion in relation to raising community engagement and building coalitions to increase uptake of new technologies will be discussed.
Mobilisation, politics, investment and constant adaptation: lessons from the Australian health‐promotion response to HIV
Authors: Brown Graham , O'Donnell Daryl , Crooks Levinia , Lake Rob
Published: April 2014

Issue addressed

The Australian response to HIV oversaw one of the most rapid and sustained changes in community behaviour in Australia's health‐promotion history. The combined action of communities of gay men, sex workers, people who inject drugs, people living with HIV and clinicians working in partnership with government, public health and research has been recognised for many years as highly successful in minimising the HIV epidemic.

Methods

This article will show how the Australian HIV partnership response moved from a crisis response to a constant and continuously adapting response, with challenges in sustaining the partnership. Drawing on key themes, lessons for broader health promotion are identified.

Results

The Australian HIV response has shown that a partnership that is engaged, politically active, adaptive and resourced to work across multiple social, structural, behavioural and health‐service levels can reduce the transmission and impact of HIV.

Conclusions

The experience of the response to HIV, including its successes and failures, has lessons applicable across health promotion. This includes the need to harness community mobilisation and action; sustain participation, investment and leadership across the partnership; commit to social, political and structural approaches; and build and use evidence from multiple sources to continuously adapt and evolve.

So what?

The Australian HIV response was one of the first health issues to have the Ottawa Charter embedded from the beginning, and has many lessons to offer broader health promotion and common challenges. As a profession and a movement, health promotion needs to engage with the interactions and synergies across the promotion of health, learn from our evidence, and resist the siloing of our responses.
Stable expression of a GFP-reporter gene in the red alga Cyanidioschyzon merolae
Authors: Watanabe Satoru , Sato Jun , Imamura Sousuke , Ohnuma Mio , Ohoba Yusaku , Chibazakura Taku , Tanaka Kan , Yoshikawa Hirofumi
Published: April 2014

The unicellular red alga Cyanidioschyzon merolae is used as a model organism to investigate the basic architecture of photosynthetic eukaryotes. We established a stable expression system for the green fluorescent protein fused with the phycocyanin-associated rod linker (APCC) protein in C. merolae, which was clearly localized on the plastid. This system should be useful in the genetic engineering of C. merolae.