bluuebunny/crossref_metadata_2025 huggingface dataset:
High resolution FTIR imaging provides automated discrimination and detection of single malaria parasite infected erythrocytes on glass
Authors: Perez-Guaita David , Andrew Dean , Heraud Philip , Beeson James , Anderson David , Richards Jack , Wood Bayden R.
Published: December 2015

New highly sensitive tools for malaria diagnostics are urgently needed to enable the detection of infection in asymptomatic carriers and patients with low parasitemia. In pursuit of a highly sensitive diagnostic tool that can identify parasite infections at the single cell level, we have been exploring Fourier transform infrared (FTIR) microscopy using a Focal Plane Array (FPA) imaging detector. Here we report for the first time the application of a new optic configuration developed by Agilent that incorporates 25× condenser and objective Cassegrain optics with a high numerical aperture (NA = 0.81) along with additional high magnification optics within the microscope to provide 0.66 micron pixel resolution (total IR system magnification of 61×) to diagnose malaria parasites at the single cell level on a conventional glass microscope slide. The high quality images clearly resolve the parasite's digestive vacuole demonstrating sub-cellular resolution using this approach. Moreover, we have developed an algorithm that first detects the cells in the infrared image, and secondly extracts the average spectrum. The average spectrum is then run through a model based on Partial Least Squares-Discriminant Analysis (PLS-DA), which diagnoses unequivocally the infected from normal cells. The high quality images, and the fact this measurement can be achieved without a synchrotron source on a conventional glass slide, shows promise as a potential gold standard for malaria detection at the single cell level.
High-precision in situ analysis of Pb isotopes in glasses using 1013 Ω resistor high gain amplifiers with ultraviolet femtosecond laser ablation multiple Faraday collector inductively coupled plasma mass spectrometry
Authors: Kimura Jun-Ichi , Chang Qing , Kanazawa Nobuyuki , Sasaki Satoshi , Vaglarov Bogdan Stefanov
Published: December 2015

The use of 1013 Ω amplifiers enabled high precision Pb isotope analysis in situ using UV femtosecond MFC-ICPMS.
Microfabricated reciprocating micropump for intracochlear drug delivery with integrated drug/fluid storage and electronically controlled dosing
Authors: Tandon Vishal , Kang Woo Seok , Robbins Tremaan A. , Spencer Abigail J. , Kim Ernest S. , McKenna Michael J. , Kujawa Sharon G. , Fiering Jason , Pararas Erin E. L. , Mescher Mark J. , Sewell William F. , Borenstein Jeffrey T.
Published: December 2015

We fabricated a micropump for reciprocating, zero-net-volume intracochlear drug delivery.
A systematic molecular dynamics approach to the structural characterization of amyloid aggregation propensity of β2-microglobulin mutant D76N
Authors: P Chandrasekaran , R Rajasekaran
Published: December 2015

Beta-2 microglobulin (β2m) is an amyloidogenic protein belonging to the immunoglobulin superfamily, responsible for the dialysis-related amyloidosis (DRA).
Understanding the chemically-reactive proteome
Authors: Jones Lyn H.
Published: December 2015

The reactivity of amino acid residues in proteins is context-dependent and difficult to predict.
Facile one-pot electrosynthesis of Al(OH)3– kinetics and equilibrium modeling for adsorption of 2,4,5-trichlorophenoxyacetic acid from aqueous solution
Authors: Kamaraj Ramakrishnan , Vasudevan Subramanyan
Published: December 2015

Nanosized Al(OH)3was prepared by a simple, cheap, and eco-friendly method. The electrocoagulant is active for the adsorption of herbicides from water.
Self-assembly of ultrathin mesoporous CoMoO4 nanosheet networks on flexible carbon fabric as a binder-free anode for lithium-ion batteries
Authors: Wang Bo , Li Songmei , Wu Xiaoyu , Liu Jianhua , Tian Wenming , Chen Jing
Published: December 2015

Novel hierarchical CoMoO4 networks assembled by ultrathin mesoporous nanosheets are directly grown on flexible carbon fabric as integrated anodes for highly efficient and reversible lithium storage.
The chemistry and biology of guanidine natural products
Authors: Berlinck Roberto G. S. , Romminger Stelamar
Published: December 2015

The present review discusses the isolation, structure determination, synthesis, biosynthesis and biological activities of secondary metabolites bearing a guanidine group.
Fast and large-area growth of uniform MoS2 monolayers on molybdenum foils
Authors: Tai Guoan , Zeng Tian , Yu Jin , Zhou Jianxin , You Yuncheng , Wang Xufeng , Wu Hongrong , Sun Xu , Hu Tingsong , Guo Wanlin
Published: December 2015

Uniform MoS2 monolayers are controllably grown by sulfurizing molybdenum foil surfaces in sulfur vapor at 600 °C within 1 min.
A SERS-active sensor based on heterogeneous gold nanostar core–silver nanoparticle satellite assemblies for ultrasensitive detection of aflatoxinB1
Authors: Li Aike , Tang Lijuan , Song Dan , Song Shanshan , Ma Wei , Xu Liguang , Kuang Hua , Wu Xiaoling , Liu Liqiang , Chen Xin , Xu Chuanlai
Published: December 2015

A surface-enhanced Raman scattering (SERS) sensor based on gold nanostar (Au NS) core–silver nanoparticle (Ag NP) satellites was fabricated for the first time to detect aflatoxinB1 (AFB1).
Comparison of strategies for non-perturbing labeling of α-synuclein to study amyloidogenesis
Authors: Haney Conor M. , Wissner Rebecca F. , Warner John B. , Wang Yanxin J. , Ferrie John J. , J. Covell Dustin , Karpowicz Richard J. , Lee Virginia M.-Y. , James Petersson E.
Published: December 2015

Complementary methods for site-specific protein labeling are used to introduce fluorescent probes into the Parkinson's Disease protein α-synuclein to examine fibril formation and cellular uptake.
Catalytic cycloaddition of 2-hydroxy ketones with 1,1-dicyanoalkenes
Authors: Tsunoi Shinji , Seo Yuta , Takano Yugo , Suzuki Itaru , Shibata Ikuya
Published: December 2015

The catalytic conversion of 2-hydroxy ketones to 2-amino-3-cyano-4-acyl-4,5-dihydrofurans was established via a 1,3-dipolar cycloaddition catalysed by Sn(Oct)2/MeOH.
Photo-reduction assisted synthesis of MnO2/reduced graphene oxide/P25 for electrochemical detection of hydrogen peroxide
Authors: Cui Shoufang , Li Yu , Deng Dongmei , Zeng Lilan , Yan Xiaoxia , Qian Jun , Luo Liqiang
Published: December 2015

MnO2/RGO/P25 nanocomposites were synthesized with a photo-reduction approach for electrochemical detection of H2O2.
Modeling of thermal conductivity of nanofluids considering aggregation and interfacial thermal resistance
Authors: Liu Meng , Ding Chen , Wang Jun
Published: December 2015

Interfacial thermal resistance was modeled and found to have a relationship to the equivalent particle size, in terms of keeping thermal resistance constant.
Unusual crystalline morphology of Poly Aryl Ether Ketones (PAEKs)
Authors: Wang Yuan , Beard James D. , Evans K. E. , Ghita Oana
Published: December 2015

SEM image showing the granular crystal blocks in the spherulite of laser sintered PEEK.
Zirconium-promoted hydrothermal synthesis of hierarchical porous carbons with ordered cubic mesostructures under acidic aqueous conditions
Authors: Zhang Anfeng , Hou Keke , Duan Haiyang , Tan Wei , Song Chunshan , Guo Xinwen
Published: December 2015

Hierarchical porous carbons with ordered cubic mesostructure (Im3m) were synthesized under acidic aqueous conditions by a zirconium-promoted hydrothermal method, F127 as template, pre-synthesized resol as precursor, and hydrochloric acid as catalyst.
Ultradrawing properties of ultrahigh molecular weight polyethylenes/functionalized activated nanocarbon as-prepared fibers
Authors: Fan Wang-xi , Wang Chuen-kai , Tsai Chih-chen , Ding Yi , Tu Zhong-dan , Huang Chao-Ming , Huang Kuo-Shien , Yeh Jen-taut
Published: December 2015

Tensile strength and modulus values of UHMWPE, UHMWPE/ANC, UHMWPE/ATANC and UHMWPE/FANCmx fibers with varying draw ratios.
Modulated multiferroic properties of MnWO4via chemical doping
Authors: Yang J. , Chen J. , Fang Y. , Han Z. D. , Yan S. M. , Qian B. , Jiang X. F. , Wang D. H. , Du Y. W.
Published: December 2015

Here we prepare polycrystalline Mn1−xNixWO4 ceramics with x = 0, 0.02, 0.04, 0.06 for investigating their magnetic, ferroelectric, and multiferroic properties.
A silica-based gel electrolyte system for improving the cycle performance of LiFePO4 batteries in an aqueous medium
Authors: Pan J. L. , Yin Y. , Wen Y. H. , Bai S. L. , Cheng J. , Cao G. P. , Yang Y. S.
Published: December 2015

Cycling performance of LiFePO4 electrodes in aqueous and gel electrolytes at a 0.5C rate.
Novel synthesis process for solar-light-active porous carbon-doped CuO nanoribbon and its photocatalytic application for the degradation of an organic dye
Authors: Hossain M. M. , Shima H. , Islam Md. A. , Hasan M. , Lee M.
Published: December 2015

A simple, one-step novel solution process was developed for the synthesis of carbon-doped CuO (C-CuO) nanoribbons without the use of a catalyst, template, substrate, or costly instrumentation at room temperature.
Sensitive and selective detection of mercury ions based on papain and 2,6-pyridinedicarboxylic acid functionalized gold nanoparticles
Authors: Lai Cui , Qin Lei , Zeng Guangming , Liu Yunguo , Huang Danlian , Zhang Chen , Xu Piao , Cheng Min , Qin Xiangbin , Wang Manman
Published: December 2015

Here we demonstrate the rational design of a sensitive and selective colorimetric method for mercury ion (Hg2+) detection by using papain and 2,6-pyridinedicarboxylic acid (PDCA) functionalized gold nanoparticles (AuNPs).
Synthesis of copolymer derived from tamarind kernel polysaccharide (TKP) and poly(methacrylic acid) via SI-ATRP with enhanced pH triggered dye removal
Authors: Pal Aniruddha , Pal Sagar
Published: December 2015

A novel copolymer derived from tamarind kernel polysaccharide (TKP) and poly(methacrylic) acid (g-TKP/pMA) has been successfully synthesised through surface initiated atom transfer radical polymerization (SI-ATRP).
A new strategy to directly construct hybrid luminescence–photothermal–magnetism multifunctional nanocomposites for cancer up-conversion imaging and photothermal therapy
Authors: Liu Wenjia , Liu Guixia , Wang Jinxian , Dong Xiangting , Yu Wensheng
Published: December 2015

Novel hybrid Ag/NaGdF4:Yb3+,Er3+ multifunctional nanocomposites with luminescence–photothermal–magnetism properties have great promise in future up-conversion luminescence imaging and photothermal therapy of tumors.
Functionalized porous carbon with appropriate pore size distribution and open hole texture prepared by H2O2 and EDTA-2Na treatment of loofa sponge and its excellent performance for supercapacitors
Authors: Yang Xiaoxiang , Li Min , Guo Nannan , Yan Ming , Yang Ru , Wang Feng
Published: December 2015

Functionalized porous carbon with an appropriate pore size distribution and open hole texture was prepared via the H2O2 and EDTA-2Na treatment of loofa sponge followed by carbonization and KOH-activation. The product was employed as a supercapacitor electrode.
Mg-modified ultra-stable Y type zeolite for the rapid catalytic co-pyrolysis of low-rank coal and biomass
Authors: Rizkiana J. , Guan G. , Widayatno W. B. , Yang J. , Hao X. , Matsuoka K. , Abudula A.
Published: December 2015

To improve the quality of oil derived from the fast co-pyrolysis of low-rank coal with biomass, various metal-modified ultra-stable Y type (USY) zeolites are mixed with the samples for the co-pyrolysis process.
Dense inter-particle interaction mediated spontaneous exchange bias in NiO nanoparticles
Authors: Gandhi Ashish Chhaganalal , Pant Jayashree , Wu Sheng Yun
Published: December 2015

The observed spontaneous exchange bias in NiO nanoparticles is induced by the dense inter-particle interactions.
Controlled synthesis of CaTiO3:Ln3+ nanocrystals for luminescence and photocatalytic hydrogen production
Authors: Meng Ling , Zhang Kaifu , Pan Kai , Qu Yang , Wang Guofeng
Published: December 2015

Bifunctional CaTiO3:Ln3+ nanocrystals not only can show very stable luminescence properties and a much higher quenching concentration due to the scheelite related structure of CaTiO3, but also can exhibit a higher activity for hydrogen production.
Utilizing modeling, experiments, and statistics for the analysis of water-splitting photoelectrodes
Authors: Gaudy Yannick K. , Haussener Sophia
Published: December 2015

A multi-physics model of a planar water-splitting photoelectrode was developed, validated, and used to identify and quantify the most significant materials-related bottlenecks in photoelectrochemical device performance.
Plasmonic silver incorporated silver halides for efficient photocatalysis
Authors: An Changhua , Wang Shutao , Sun Yugang , Zhang Qinhui , Zhang Jun , Wang Chenyu , Fang Jiye
Published: December 2015

The review provides an overall survey on the state-of-the-art silver–silver halide-based photocatalysts, fundamental understanding of their plasmonically induced photo-reactions and their major environmental applications.
Template-free synthesis of boron nitride foam-like porous monoliths and their high-end applications in water purification
Authors: Xue Yanming , Dai Pengcheng , Jiang Xiangfen , Wang Xuebin , Zhang Chao , Tang Daiming , Weng Qunhong , Wang Xi , Pakdel Amir , Tang Chengchun , Bando Yoshio , Golberg Dmitri
Published: December 2015

New boron nitride porous monoliths with high efficiency and excellent adsorption applications were successfully fabricated by a brand-new and template-free method.
The hierarchical nanowires array of iron phosphide integrated on a carbon fiber paper as an effective electrocatalyst for hydrogen generation
Authors: Lv Cuncai , Peng Zhen , Zhao Yaoxing , Huang Zhipeng , Zhang Chi
Published: December 2015

A hierarchical nanowires array of iron phosphide on a carbon fiber paper was constructed, which exhibited remarkable catalytic activity in hydrogen evolution reaction.
Beyond graphene foam, a new form of three-dimensional graphene for supercapacitor electrodes
Authors: Zhang Lu , DeArmond Derek , Alvarez Noe T. , Zhao Daoli , Wang Tingting , Hou Guangfeng , Malik Rachit , Heineman William R. , Shanov Vesselin
Published: December 2015

Graphene foam (GF) is a three-dimensional (3D) graphene structure that has been intensively studied as an electrode material for energy storage applications. Here we report a new design and fabrication process of an electrode material called graphene pellet (GP) for energy storage applications.
Hollow ZrO2/PPy nanoplatform for improved drug delivery and real-time CT monitoring in synergistic photothermal-chemo cancer therapy
Authors: Tan Longfei , Liu Tianlong , Fu Changhui , Wang Shengping , Fu Shiyan , Ren Jun , Meng Xianwei
Published: December 2015

Hollow ZrO2 nanospheres are fabricated to integrate polypyrrole and doxorubicin into one platform for synergistic photothermal-chemo therapy, and in vivo biodistribution is monitored by real-time CT imaging.
Effect of Fe-doping on the structure and magnetoelectric properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 synthesized by a chemical route
Authors: Venkata Ramana E. , Figueiras F. , Mahajan A. , Tobaldi David Maria , Costa Benilde F. O. , Graça M. P. F. , Valente M. A.
Published: December 2015

B-site Fe-doped (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 was synthesized by a facile chemical route to study the effect of doping on its physical properties.
A facile formulation and excellent electromagnetic absorption of room temperature curable polyaniline nanofiber based inks
Authors: Joseph Nina , Varghese Jobin , Sebastian Mailadil Thomas
Published: December 2015

Ultra low thickness EMI shielding inks.
A series of fluorinated phenylpyridine-based electron-transporters for blue phosphorescent OLEDs
Authors: Kamata Takahiro , Sasabe Hisahiro , Watanabe Yuichirio , Yokoyama Daisuke , Katagiri Hiroshi , Kido Junji
Published: December 2015

A series of fluorinated phenylpyridine-based electron-transport materials were developed and the influence of fluorine atom(s) on molecular orientation and mobility was investigated.
Who’s in charge? Corporations as institutions of global governance
Authors: May Christopher
Published: December 2015

In most accounts of global governance, where corporations are included, they are seen as either subject to various international organisations’ regulatory impact or are identified as having (benign or malign) influence over agenda setting around the scope and practices of global regulation. However, here I examine a third dimension that has hitherto been under recognised: this article starts to develop an analysis of the terrain that global corporations govern themselves, sometime singularly, sometimes collectively and sometimes collaborating with the more “normal” institutions of global governance. I seek to develop an account of how the corporation governs this terrain and the mechanisms that businesses have developed (or utilised) to maintain their authority. I suggest that it makes sense to understand global corporations as directly analogous to more “normal” institutions of global governance, and that discussion and analysis of global governance needs to integrate this third dimension if it is to examine the full spectrum of governance beyond the state. This article is published as part of a thematic collection dedicated to global governance.
Injection of auxiliary electrons for increasing the plasma density in highly charged and high intensity ion sources
Authors: Odorici F. , Malferrari L. , Montanari A. , Rizzoli R. , Mascali D. , Castro G. , Celona L. , Gammino S. , Neri L.
Published: December 2015

Different electron guns based on cold- or hot-cathode technologies have been developed since 2009 at INFN for operating within ECR plasma chambers as sources of auxiliary electrons, with the aim of boosting the source performances by means of a higher plasma lifetime and density. Their application to microwave discharge ion sources, where plasma is not confined, has required an improvement of the gun design, in order to “screen” the cathode from the plasma particles. Experimental tests carried out on a plasma reactor show a boost of the plasma density, ranging from 10% to 90% when the electron guns are used, as explained by plasma diffusion models.
Direct numerical simulation of supersonic turbulent flows around a tandem expansion-compression corner
Authors: Fang Jian , Yao Yufeng , Zheltovodov Alexandr A. , Li Zhaorui , Lu Lipeng
Published: December 2015

The M = 2.9 supersonic turbulent flows over a tandem expansion-compression corner configuration with a sharp deflection angle of 25° at three Reynolds numbers Reδ = 20 000, 40 000, and 80 000 were studied by using direct numerical simulation. The flow statistics were validated against available experimental measurements and other numerical predictions. The flow structures and turbulence statistics were detailed visualized and analysed for the Reδ = 40 000 case, especially in the interaction region where flow separation and reattachment occurred. It was found that during the expansion process, the boundary layer exhibited a characteristic two-layer structure also discovered in previous experimental studies, and the turbulence evolved differently within these two layers. In the outer layer, the turbulence was consistently suppressed along the ramp to a large extent, while in the inner layer, it was suppressed only in a small region around the expansion corner, and the near-wall quasi-streamwise vortices were well preserved. Flow patterns near the reattachment line have shown the existence of the Görtler-type vortices, which would largely amplify turbulence fluctuations in the near-wall region, thus promoting the regeneration of wall turbulence that in turn contributed to the redevelopment of a downstream turbulent boundary layer. The Reynolds number effects and the characteristics of coherent structures were also discussed. With the increase of the Reynolds number, the separation bubble size decreased, but the pattern and the characteristic size of wall streamlines near the reattachment line were preserved.
Vortex breakdown in closed containers with polygonal cross sections
Authors: Naumov I. V. , Dvoynishnikov S. V. , Kabardin I. K. , Tsoy M. A.
Published: December 2015

The vortex breakdown bubble in the confined flow generated by a rotating lid in closed containers with polygonal cross sections was analysed both experimentally and numerically for the height/radius aspect ratio equal to 2. The stagnation point locations of the breakdown bubble emergence and the corresponding Reynolds number were determined experimentally and in addition computed numerically by STAR-CCM+ CFD software for square, pentagonal, hexagonal, and octagonal cross section configurations. The flow pattern and the velocity were observed and measured by combining the seeding particle visualization and the temporal accuracy of laser Doppler anemometry. The vortex breakdown size and position on the container axis were determined for Reynolds numbers, ranging from 1450 to 2400. The obtained results were compared with the flow structure in the closed container of cubical and cylindrical configurations. It is shown that the measured evolution of steady vortex breakdown is in close agreement with the numerical results.
Flexible spin-orbit torque devices
Authors: Lee OukJae , You Long , Jang Jaewon , Subramanian Vivek , Salahuddin Sayeef
Published: December 2015

We report on state-of-the-art spintronic devices synthesized and fabricated directly on a flexible organic substrate. Large perpendicular magnetic anisotropy was achieved in ultrathin ferromagnetic heterostructures of Pt/Co/MgO sputtered on a non-rigid plastic substrate at room temperature. Subsequently, a full magnetic reversal of the Co was observed by exploiting the spin orbit coupling in Pt that leads to a spin accumulation at the Pt/Co interface when an in-plane current is applied. Quasi-static measurements show the potential for operating these devices at nano-second speeds. Importantly, the behavior of the devices remained unchanged under varying bending conditions (up to a bending radius of ≈ ±20–30 mm). Furthermore, the devices showed robust operation even after application of 106 successive pulses, which is likely sufficient for many flexible applications. Thus, this work demonstrates the potential for integrating high performance spintronic devices on flexible substrates, which could lead to many applications ranging from flexible non-volatile magnetic memory to local magnetic resonance imaging.
Charge-dependent many-body exchange and dispersion interactions in combined QM/MM simulations
Authors: Kuechler Erich R. , Giese Timothy J. , York Darrin M.
Published: December 2015

Accurate modeling of the molecular environment is critical in condensed phase simulations of chemical reactions. Conventional quantum mechanical/molecular mechanical (QM/MM) simulations traditionally model non-electrostatic non-bonded interactions through an empirical Lennard-Jones (LJ) potential which, in violation of intuitive chemical principles, is bereft of any explicit coupling to an atom’s local electronic structure. This oversight results in a model whereby short-ranged exchange-repulsion and long-ranged dispersion interactions are invariant to changes in the local atomic charge, leading to accuracy limitations for chemical reactions where significant atomic charge transfer can occur along the reaction coordinate. The present work presents a variational, charge-dependent exchange-repulsion and dispersion model, referred to as the charge-dependent exchange and dispersion (QXD) model, for hybrid QM/MM simulations. Analytic expressions for the energy and gradients are provided, as well as a description of the integration of the model into existing QM/MM frameworks, allowing QXD to replace traditional LJ interactions in simulations of reactive condensed phase systems. After initial validation against QM data, the method is demonstrated by capturing the solvation free energies of a series of small, chlorine-containing compounds that have varying charge on the chlorine atom. The model is further tested on the SN2 attack of a chloride anion on methylchloride. Results suggest that the QXD model, unlike the traditional LJ model, is able to simultaneously obtain accurate solvation free energies for a range of compounds while at the same time closely reproducing the experimental reaction free energy barrier. The QXD interaction model allows explicit coupling of atomic charge with many-body exchange and dispersion interactions that are related to atomic size and provides a more accurate and robust representation of non-electrostatic non-bonded QM/MM interactions.
Ridge-based bias potentials to accelerate molecular dynamics
Authors: Xiao Penghao , Duncan Juliana , Zhang Liang , Henkelman Graeme
Published: December 2015

An effective way to accelerate rare events in molecular dynamics simulations is to apply a bias potential which destabilizes minima without biasing the transitions between stable states. This approach, called hyperdynamics, is limited by our ability to construct general bias potentials without having to understand the reaction mechanisms available to the system, a priori. Current bias potentials are typically constructed in terms of a metric which quantifies the distance that a trajectory deviates from the reactant state minimum. Such metrics include detection of negative curvatures of the potential, an energy increase, or deviations in bond lengths from the minimum. When one of these properties exceeds a critical value, the bias potentials are constructed to approach zero. A problem common to each of these schemes is that their effectiveness decreases rapidly with system size. We attribute this problem to a diminishing volume defined by the metrics around a reactant minimum as compared to the total volume of the reactant state basin. In this work, we mitigate the dimensionality scaling problem by constructing bias potentials that are based upon the distance to the boundary of the reactant basin. This distance is quantified in two ways: (i) by following the minimum mode direction to the reactant boundary and (ii) by training a machine learning algorithm to give an analytic expression for the boundary to which the distance can be calculated. Both of these ridge-based bias potentials are demonstrated to scale qualitatively better with dimensionality than the existing methods. We attribute this improvement to a greater filling fraction of the reactant state using the ridge-based bias potentials as compared to the standard potentials.
Shaping the spatial and spectral emissivity at the diffraction limit
Authors: Makhsiyan Mathilde , Bouchon Patrick , Jaeck Julien , Pelouard Jean-Luc , Haïdar Riad
Published: December 2015

Metasurfaces have attracted a growing interest for their ability to artificially tailor an electromagnetic response on various spectral ranges. In particular, thermal sources with unprecedented abilities, such as directionality or monochromaticity, have been achieved. However, these metasurfaces exhibit homogeneous optical properties whereas the spatial modulation of the emissivity up to the wavelength scale is at the crux of the design of original emitters. In this letter, we study an inhomogeneous metasurface made of a nonperiodic set of optical nano-antennas that spatially and spectrally control the emitted light up to the diffraction limit. Each antenna acts as an independent deep subwavelength emitter for given polarization and wavelength. Their juxtaposition at the subwavelength scale encodes far field multispectral and polarized images. This opens up promising breakthroughs for applications such as optical storage, anti-counterfeit devices, and multispectral emitters for biochemical sensing.
A nonlinear MEMS electrostatic kinetic energy harvester for human-powered biomedical devices
Authors: Lu Y. , Cottone F. , Boisseau S. , Marty F. , Galayko D. , Basset P.
Published: December 2015

This article proposes a silicon-based electrostatic kinetic energy harvester with an ultra-wide operating frequency bandwidth from 1 Hz to 160 Hz. This large bandwidth is obtained, thanks to a miniature tungsten ball impacting with a movable proof mass of silicon. The motion of the silicon proof mass is confined by nonlinear elastic stoppers on the fixed part standing against two protrusions of the proof mass. The electrostatic transducer is made of interdigited-combs with a gap-closing variable capacitance that includes vertical electrets obtained by corona discharge. Below 10 Hz, the e-KEH offers 30.6 nJ per mechanical oscillation at 2 grms, which makes it suitable for powering biomedical devices from human motion. Above 10 Hz and up to 162 Hz, the harvested power is more than 0.5 μW with a maximum of 4.5 μW at 160 Hz. The highest power of 6.6 μW is obtained without the ball at 432 Hz, in accordance with a power density of 142 μW/cm3. We also demonstrate the charging of a 47-μF capacitor to 3.5 V used to power a battery-less wireless temperature sensor node.
Vacuum upgrade and enhanced performances of the double imaging electron/ion coincidence end-station at the vacuum ultraviolet beamline DESIRS
Authors: Tang Xiaofeng , Garcia Gustavo A. , Gil Jean-François , Nahon Laurent
Published: December 2015

We report here the recent upgrade of the SAPHIRS permanent photoionization end-station at the DESIRS vacuum ultraviolet beamline of synchrotron SOLEIL, whose performances have been enhanced by installing an additional double-skimmer differential chamber. The smaller molecular beam profile obtained at the interaction region has increased the mass resolution of the double imaging photoelectron photoion coincidence (i2PEPICO) spectrometer, DELICIOUS III, installed in the photoionization chamber of the SAPHIRS endstation, by a factor of two, to M/ΔM ∼ 1700 (FWHM). The electron kinetic energy resolution offered by the velocity map imaging (VMI) part of the spectrometer has been improved down to 2.8% (ΔE/E) as we show on the N2 photoionization case in the double skimmer configuration. As a representative example of the overall state-of-the-art i2PEPICO performances, experimental results of the dissociation of state-selected O2+ (B2∑g−, v+ = 0-6) molecular ions performed at the fixed photon energy of hν = 21.1 eV are presented.
Desynchronization of stochastically synchronized chemical oscillators
Authors: Snari Razan , Tinsley Mark R. , Wilson Dan , Faramarzi Sadegh , Netoff Theoden Ivan , Moehlis Jeff , Showalter Kenneth
Published: December 2015

Experimental and theoretical studies are presented on the design of perturbations that enhance desynchronization in populations of oscillators that are synchronized by periodic entrainment. A phase reduction approach is used to determine optimal perturbation timing based upon experimentally measured phase response curves. The effectiveness of the perturbation waveforms is tested experimentally in populations of periodically and stochastically synchronized chemical oscillators. The relevance of the approach to therapeutic methods for disrupting phase coherence in groups of stochastically synchronized neuronal oscillators is discussed.
A time-resolved imaging and electrical study on a high current atmospheric pressure spark discharge
Authors: Palomares J. M. , Kohut A. , Galbács G. , Engeln R. , Geretovszky Zs.
Published: December 2015

We present a time-resolved imaging and electrical study of an atmospheric pressure spark discharge. The conditions of the present study are those used for nanoparticle generation in spark discharge generator setups. The oscillatory bipolar spark discharge was generated between two identical Cu electrodes in different configurations (cylindrical flat-end or tipped-end geometries, electrode gap from 0.5 to 4 mm), in a controlled co-axial N2 flow, and was supplied by a high voltage capacitor. Imaging data with nanosecond time resolution were collected using an intensified CCD camera. This data were used to study the time evolution of plasma morphology, total light emission intensity, and the rate of plasma expansion. High voltage and high current probes were employed to collect electrical data about the discharge. The electrical data recorded allowed, among others, the calculation of the equivalent resistance and inductance of the circuit, estimations for the energy dissipated in the spark gap. By combining imaging and electrical data, observations could be made about the correlation of the evolution of total emitted light and the dissipated power. It was also observed that the distribution of light emission of the plasma in the spark gap is uneven, as it exhibits a “hot spot” with an oscillating position in the axial direction, in correlation with the high voltage waveform. The initial expansion rate of the cylindrical plasma front was found to be supersonic; thus, the discharge releases a strong shockwave. Finally, the results on equivalent resistance and channel expansion are comparable to those of unipolar arcs. This shows the spark discharge has a similar behavior to the arc regime during the conductive phase and until the current oscillations stop.
Irregular conformal blocks, with an application to the fifth and fourth Painlevé equations
Authors: Nagoya Hajime
Published: December 2015

We develop the theory of irregular conformal blocks of the Virasoro algebra. In previous studies, expansions of irregular conformal blocks at regular singular points were obtained as degeneration limits of regular conformal blocks; however, such expansions at irregular singular points were not clearly understood. This is because precise definitions of irregular vertex operators had not been provided previously. In this paper, we present precise definitions of irregular vertex operators of two types and we prove that one of our vertex operators exists uniquely. Then, we define irregular conformal blocks with at most two irregular singular points as expectation values of given irregular vertex operators. Our definitions provide an understanding of expansions of irregular conformal blocks and enable us to obtain expansions at irregular singular points. As an application, we propose conjectural formulas of series expansions of the tau functions of the fifth and fourth Painlevé equations, using expansions of irregular conformal blocks at an irregular singular point.
Path optimization by a variational reaction coordinate method. I. Development of formalism and algorithms
Authors: Birkholz Adam B. , Schlegel H. Bernhard
Published: December 2015

The development of algorithms to optimize reaction pathways between reactants and products is an active area of study. Existing algorithms typically describe the path as a discrete series of images (chain of states) which are moved downhill toward the path, using various reparameterization schemes, constraints, or fictitious forces to maintain a uniform description of the reaction path. The Variational Reaction Coordinate (VRC) method is a novel approach that finds the reaction path by minimizing the variational reaction energy (VRE) of Quapp and Bofill. The VRE is the line integral of the gradient norm along a path between reactants and products and minimization of VRE has been shown to yield the steepest descent reaction path. In the VRC method, we represent the reaction path by a linear expansion in a set of continuous basis functions and find the optimized path by minimizing the VRE with respect to the linear expansion coefficients. Improved convergence is obtained by applying constraints to the spacing of the basis functions and coupling the minimization of the VRE to the minimization of one or more points along the path that correspond to intermediates and transition states. The VRC method is demonstrated by optimizing the reaction path for the Müller-Brown surface and by finding a reaction path passing through 5 transition states and 4 intermediates for a 10 atom Lennard-Jones cluster.
Calculation of the dynamic first electronic hyperpolarizability β(−ω
σ; ω1, ω2) of periodic systems. Theory, validation, and application to multi-layer MoS2
Authors: Maschio Lorenzo , Rérat Michel , Kirtman Bernard , Dovesi Roberto
Published: December 2015

We describe our implementation of a fully analytical scheme, based on the 2n + 1 rule, for computing the coupled perturbed Hartree Fock and Kohn-Sham dynamic first hyperpolarizability tensor β(−ωσ; ω1, ω2) of periodic 1D (polymer), 2D (slab), and 3D (crystal) systems in the CRYSTAL code [R. Dovesi et al., Int. J. Quantum Chem. 114, 1287 (2014)], which utilizes local Gaussian type basis sets. The dc-Pockels (dc-P) and second harmonic generation (SHG) tensors are included as special cases. It is verified that (i) symmetry requirements are satisfied; (ii) using LiF as an example, the infinite periodic polymer result agrees with extrapolated finite oligomer calculations and, likewise, for the build-up to a 2D slab and a 3D crystal; (iii) the values converge to the static case for low frequencies; and (iv) the Bishop-deKee dispersion formulas relating dc-P, SHG, and general processes are reproduced through quartic terms. Preliminary SHG calculations on multi-layer MoS2 satisfactorily reproduce experimental data.
Parameters for Martini sterols and hopanoids based on a virtual-site description
Authors: Melo M. N. , Ingólfsson H. I. , Marrink S. J.
Published: December 2015

Sterols play an essential role in modulating bilayer structure and dynamics. Coarse-grained molecular dynamics parameters for cholesterol and related molecules are available for the Martini force field and have been successfully used in multiple lipid bilayer studies. In this work, we focus on the use of virtual sites as a means of increasing the stability of cholesterol and cholesterol-like structures. We improve and extend the Martini parameterization of sterols in four different ways: 1—the cholesterol parameters were adapted to make use of virtual interaction sites, which markedly improves numerical stability; 2—cholesterol parameters were also modified to address reported shortcomings in reproducing correct lipid phase behavior in mixed membranes; 3—parameters for ergosterol were created and adapted from cholesterols; and 4—parameters for the hopanoid class of bacterial polycyclic molecules were created, namely, for hopane, diploptene, bacteriohopanetetrol, and for their polycyclic base structure.
Modification of transparent materials with ultrashort laser pulses: What is energetically and mechanically meaningful?
Authors: Bulgakova Nadezhda M. , Zhukov Vladimir P. , Sonina Svetlana V. , Meshcheryakov Yuri P.
Published: December 2015

A comprehensive analysis of laser-induced modification of bulk glass by single ultrashort laser pulses is presented which is based on combination of optical Maxwell-based modeling with thermoelastoplastic simulations of post-irradiation behavior of matter. A controversial question on free electron density generated inside bulk glass by ultrashort laser pulses in modification regimes is addressed on energy balance grounds. Spatiotemporal dynamics of laser beam propagation in fused silica have been elucidated for the regimes used for direct laser writing in bulk glass. 3D thermoelastoplastic modeling of material relocation dynamics under laser-induced stresses has been performed up to the microsecond timescale when all motions in the material decay. The final modification structure is found to be imprinted into material matrix already at sub-nanosecond timescale. Modeling results agree well with available experimental data on laser light transmission through the sample and the final modification structure.
Enhanced impurity-limited mobility in ultra-scaled Si nanowire junctionless field-effect transistors
Authors: Ueda Akiko , Luisier Mathieu , Sano Nobuyuki
Published: December 2015

We examine the transport properties of heavily doped ultra-scaled Si junctionless nanowire field-effect transistors, by means of atomistic quantum transport simulations based on the sp3d5s∗ tight-binding model, the nonequilibrium Green's function formalism, and including electron-phonon scattering. Each individual doping atom is treated explicitly and its potential is determined by solving the Poisson equation. The impurity atoms are assumed to be aligned along a single line or to slightly vary from this well-ordered configuration. We find that the impurity-limited mobility enhances as the carrier concentration increases due to the screening effect. The mobility also improves with the doping concentration because closely placed impurities induce resonant tunneling states that positively affect the current magnitude. This behavior is found to persist even in the case of slight disorder.
Thermal evolution behavior and fluid dynamics during laser additive manufacturing of Al-based nanocomposites: Underlying role of reinforcement weight fraction
Authors: Gu Dongdong , Yuan Pengpeng
Published: December 2015

In this study, a three-dimensional transient computational fluid dynamics model was established to investigate the influence of reinforcement weight fraction on thermal evolution behavior and fluid dynamics during selective laser melting (SLM) additive manufacturing of TiC/AlSi10Mg nanocomposites. The powder-to-solid transition and nonlinear variation of thermal physical properties of as-used materials were considered in the numerical model, using the Gaussian distributed volumetric heat source. The simulation results showed that the increase of operating temperature and the resultant formation of larger melt pool were caused by the increase of weight fraction of reinforcement. The Marangoni convection was intensified using a larger reinforcement content, accelerating the coupled motion of fluid and solid particles. The circular flows appeared when the TiC content reached 5.0 wt. % and the larger-sized circular flows were present as the reinforcement content increased to 7.5 wt. %. The experimental study on surface morphologies and microstructures on the polished sections of SLM-processed TiC/AlSi10Mg nanocomposite parts was performed. A considerably dense and smooth surface free of any balling effect and pore formation was obtained when the reinforcement content was optimized at 5.0 wt. %, due to the sufficient liquid formation and moderate Marangoni flow. Novel ring-structured reinforcing particulates were tailored because of the combined action of the attractive effect of centripetal force and repulsive force, which was consistent with the simulation results.
Stability of standing spin wave in permalloy thin film studied by anisotropic magnetoresistance effect
Authors: Yamanoi K. , Yokotani Y. , Cui X. , Yakata S. , Kimura T.
Published: December 2015

We have investigated the stability for the resonant spin precession under the strong microwave magnetic field by a specially developed detection method using the anisotropic magnetoresistance effect. The electrically separated excitation and detection circuits enable us to investigate the influence of the heating effect and the nonuniform spin dynamics independently. The large detecting current is found to induce the field shift of the resonant spectra because of the Joule heating. From the microwave power dependence, we found that the linear response regime for the standing spin wave is larger than that for the ferromagnetic resonance. This robust characteristic of the standing spin wave is an important advantage for the high power operation of the spin-wave device.
Minimal moment equations for stochastic models of biochemical reaction networks with partially finite state space
Authors: Ruess Jakob
Published: December 2015

Many stochastic models of biochemical reaction networks contain some chemical species for which the number of molecules that are present in the system can only be finite (for instance due to conservation laws), but also other species that can be present in arbitrarily large amounts. The prime example of such networks are models of gene expression, which typically contain a small and finite number of possible states for the promoter but an infinite number of possible states for the amount of mRNA and protein. One of the main approaches to analyze such models is through the use of equations for the time evolution of moments of the chemical species. Recently, a new approach based on conditional moments of the species with infinite state space given all the different possible states of the finite species has been proposed. It was argued that this approach allows one to capture more details about the full underlying probability distribution with a smaller number of equations. Here, I show that the result that less moments provide more information can only stem from an unnecessarily complicated description of the system in the classical formulation. The foundation of this argument will be the derivation of moment equations that describe the complete probability distribution over the finite state space but only low-order moments over the infinite state space. I will show that the number of equations that is needed is always less than what was previously claimed and always less than the number of conditional moment equations up to the same order. To support these arguments, a symbolic algorithm is provided that can be used to derive minimal systems of unconditional moment equations for models with partially finite state space.
A perturbative solution to metadynamics ordinary differential equation
Authors: Tiwary Pratyush , Dama James F. , Parrinello Michele
Published: December 2015

Metadynamics is a popular enhanced sampling scheme wherein by periodic application of a repulsive bias, one can surmount high free energy barriers and explore complex landscapes. Recently, metadynamics was shown to be mathematically well founded, in the sense that the biasing procedure is guaranteed to converge to the true free energy surface in the long time limit irrespective of the precise choice of biasing parameters. A differential equation governing the post-transient convergence behavior of metadynamics was also derived. In this short communication, we revisit this differential equation, expressing it in a convenient and elegant Riccati-like form. A perturbative solution scheme is then developed for solving this differential equation, which is valid for any generic biasing kernel. The solution clearly demonstrates the robustness of metadynamics to choice of biasing parameters and gives further confidence in the widely used method.