WorldWideScience

Sample records for electrode work function

  1. Systems and methods for producing low work function electrodes

    Science.gov (United States)

    Kippelen, Bernard; Fuentes-Hernandez, Canek; Zhou, Yinhua; Kahn, Antoine; Meyer, Jens; Shim, Jae Won; Marder, Seth R.

    2015-07-07

    According to an exemplary embodiment of the invention, systems and methods are provided for producing low work function electrodes. According to an exemplary embodiment, a method is provided for reducing a work function of an electrode. The method includes applying, to at least a portion of the electrode, a solution comprising a Lewis basic oligomer or polymer; and based at least in part on applying the solution, forming an ultra-thin layer on a surface of the electrode, wherein the ultra-thin layer reduces the work function associated with the electrode by greater than 0.5 eV. According to another exemplary embodiment of the invention, a device is provided. The device includes a semiconductor; at least one electrode disposed adjacent to the semiconductor and configured to transport electrons in or out of the semiconductor.

  2. High work function transparent middle electrode for organic tandem solar cells

    NARCIS (Netherlands)

    Moet, D. J. D.; de Bruyn, P.; Blom, P. W. M.

    2010-01-01

    The use of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) in combination with ZnO as middle electrode in solution-processed organic tandem solar cells requires a pH modification of the PEDOT:PSS dispersion. We demonstrate that this neutralization leads to a reduced work function

  3. Determination of work function of graphene under a metal electrode and its role in contact resistance.

    Science.gov (United States)

    Song, Seung Min; Park, Jong Kyung; Sul, One Jae; Cho, Byung Jin

    2012-08-08

    Although the work function of graphene under a given metal electrode is critical information for the realization of high-performance graphene-based electronic devices, relatively little relevant research has been carried out to date. In this work, the work function values of graphene under various metals are accurately measured for the first time through a detailed analysis of the capacitance-voltage (C-V) characteristics of a metal-graphene-oxide-semiconductor (MGOS) capacitor structure. In contrast to the high work function of exposed graphene of 4.89-5.16 eV, the work function of graphene under a metal electrode varies depending on the metal species. With a Cr/Au or Ni contact, the work function of graphene is pinned to that of the contacted metal, whereas with a Pd or Au contact the work function assumes a value of ∼4.62 eV regardless of the work function of the contact metal. A study of the gate voltage dependence on the contact resistance shows that the latter case provides lower contact resistance.

  4. Temperature dependence of the work function of ruthenium-based gate electrodes

    International Nuclear Information System (INIS)

    Alshareef, H.N.; Wen, H.C.; Luan, H.F.; Choi, K.; Harris, H.R.; Senzaki, Y.; Majhi, P.; Lee, B.H.; Foran, B.; Lian, G.

    2006-01-01

    The effect of device fabrication temperature on the work function of ruthenium (Ru) metal gate and its bilayers was investigated. The work function shows strong temperature dependence when Ru electrodes are deposited on silicon oxide, SiO 2 , but not on hafnium silicates (HfSiO x ). Specifically, the work function of Ru on SiO 2 increased from 4.5 eV at 500 deg. C to 5.0 eV at 700 deg. C. On further annealing to 900 deg. C or higher, the work function dropped to about 4.4 eV. In the case of HfSiO x , the work function of Ru changed by less than 100 mV over the same temperature range. Identical temperature dependence was observed using hafnium (Hf)/Ru and tantalum (Ta)/Ru bilayers. However, the peak values of the work function decreased with increasing Hf/Ru and Ta/Ru thickness ratios. Materials analysis suggests that these trends are driven by interactions at the Ru metal gate-dielectric interface

  5. Noise analysis of gate electrode work function engineered recessed channel (GEWE-RC) MOSFET

    International Nuclear Information System (INIS)

    Agarwala, Ajita; Chaujar, Rishu

    2012-01-01

    This paper discusses the noise assessment, using ATLAS device simulation software, of a gate electrode work function engineered recessed channel (GEWE-RC) MOSFET involving an RC and GEWE design integrated onto a conventional MOSFET. Furthermore, the behaviour of GEWE-RC MOSFET is compared with that of a conventional MOSFET having the same device parameters. This paper thus optimizes and predicts the feasibility of a novel design, i.e., GEWE-RC MOSFET for high-performance applications where device and noise reduction is a major concern. The noise metrics taken into consideration are: minimum noise figure and optimum source impedance. The statistical tools auto correlation and cross correlation are also analysed owing to the random nature of noise.

  6. Large-area functionalized CVD graphene for work function matched transparent electrodes

    Science.gov (United States)

    Bointon, Thomas H.; Jones, Gareth F.; de Sanctis, Adolfo; Hill-Pearce, Ruth; Craciun, Monica F.; Russo, Saverio

    2015-11-01

    The efficiency of flexible photovoltaic and organic light emitting devices is heavily dependent on the availability of flexible and transparent conductors with at least a similar workfunction to that of Indium Tin Oxide. Here we present the first study of the work function of large area (up to 9 cm2) FeCl3 intercalated graphene grown by chemical vapour deposition on Nickel, and demonstrate values as large as 5.1 eV. Upon intercalation, a charge density per graphene layer of 5 ṡ 1013 ± 5 ṡ 1012 cm-2 is attained, making this material an attractive platform for the study of plasmonic excitations in the infrared wavelength spectrum of interest to the telecommunication industry. Finally, we demonstrate the potential of this material for flexible electronics in a transparent circuit on a polyethylene naphthalate substrate.

  7. Electronic structure of low work function electrodes modified by C{sub 16}H{sub 33}SH

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyunbok [Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA, 01003 (United States); Cho, Sang Wan, E-mail: dio8027@yonsei.ac.kr [Department of Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do, 220-710 (Korea, Republic of); Park, Sang Han; Cho, Mann-Ho; Yi, Yeonjin [Institute of Physics and Applied Physics, Yonsei University, 50 Yonsei-ro, Seodaemoon-Gu, Seoul, 120-749 (Korea, Republic of)

    2014-10-15

    Highlights: • The electronic structure of pentacene/C{sub 16}H{sub 33}SH/Au is investigated. • The work function of Au is significantly decreased with C{sub 16}H{sub 33}SH treatment. • The reduced work function is attributed to its permanent dipole moment. - Abstract: Organic and printed electronics technologies require electrodes with low work functions to facilitate the transport of electrons in and out of various optoelectronic devices. We show that the surface modifier of 1-hexadecanethiol reduces the work function of conductors using in situ ultraviolet photoemission spectroscopy, and we combine experimental and theoretical methods to investigate the origin of the work function changes. The interfacial electronic structures of pentacene/1-hexadecanethiol/Au were investigated via in situ ultraviolet photoemission spectroscopy and X-ray photoemission spectroscopy in order to understand the change in the carrier injection barrier and chemical reactions upon surface modification. Theoretical calculations using density functional theory were also performed to understand the charge distribution of 1-hexadecanethiol, which affects the reduction of the work function. The 1-hexadecanethiol surface modifier is processed in air from solution, providing an appealing alternative to chemically-reactive low-work-function metals.

  8. The effects of electron and hole transport layer with the electrode work function on perovskite solar cells

    Science.gov (United States)

    Deng, Quanrong; Li, Yiqi; Chen, Lian; Wang, Shenggao; Wang, Geming; Sheng, Yonglong; Shao, Guosheng

    2016-09-01

    The effects of electron and hole transport layer with the electrode work function on perovskite solar cells with the interface defects were simulated by using analysis of microelectronic and photonic structures-one-dimensional (AMPS-1D) software. The simulation results suggest that TiO2 electron transport layer provides best device performance with conversion efficiency of 25.9% compared with ZnO and CdS. The threshold value of back electrode work function for Spiro-OMeTAD, NiO, CuI and Cu2O hole transport layer are calculated to be 4.9, 4.8, 4.7 and 4.9 eV, respectively, to reach the highest conversion efficiency. The mechanisms of device physics with various electron and hole transport materials are discussed in details. The device performance deteriorates gradually as the increased density of interface defects located at ETM/absorber or absorber/HTM. This research results can provide helpful guidance for materials and metal electrode choice for perovskite solar cells.

  9. Work function tuning of tin-doped indium oxide electrodes with solution-processed lithium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Ow-Yang, C.W., E-mail: cleva@sabanciuniv.edu [Materials Science and Engineering Program, Sabanci University, Orhanli, Tuzla, 34956 Istanbul (Turkey); Nanotechnology Application Center, Sabanci University, Orhanli, Tuzla, 34956 Istanbul (Turkey); Jia, J. [Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258 (Japan); Aytun, T. [Materials Science and Engineering Program, Sabanci University, Orhanli, Tuzla, 34956 Istanbul (Turkey); Zamboni, M.; Turak, A. [Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4L8 (Canada); Saritas, K. [Materials Science and Engineering Program, Sabanci University, Orhanli, Tuzla, 34956 Istanbul (Turkey); Shigesato, Y. [Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258 (Japan)

    2014-05-30

    Solution-processed lithium fluoride (sol-LiF) nanoparticles synthesized in polymeric micelle nanoreactors enabled tuning of the surface work function of tin-doped indium oxide (ITO) films. The micelle reactors provided the means for controlling surface coverage by progressively building up the interlayer through alternating deposition and plasma etch removal of the polymer. In order to determine the surface coverage and average interparticle distance, spatial point pattern analysis was applied to scanning electron microscope images of the nanoparticle dispersions. The work function of the sol-LiF modified ITO, obtained from photoelectron emission yield spectroscopy analysis, was shown to increase with surface coverage of the sol-LiF particles, suggesting a lateral depolarization effect. Analysis of the photoelectron emission energy distribution in the near threshold region revealed the contribution of surface states for surface coverage in excess of 14.1%. Optimization of the interfacial barrier was achieved through contributions from both work function modification and surface states. - Highlights: • Work function of indium tin oxide increased with LiF nanoparticle coverage. • Work function was analyzed via photoelectron emission yield (PEYS). • At higher surface coverage, the energy distribution of PEYS increased. • Pre-threshold increase in PEYS consistent with emission from surface states.

  10. Two-dimensional threshold voltage model and design considerations for gate electrode work function engineered recessed channel nanoscale MOSFET: I

    International Nuclear Information System (INIS)

    Chaujar, Rishu; Kaur, Ravneet; Gupta, Mridula; Gupta, R S; Saxena, Manoj

    2009-01-01

    This paper discusses a threshold voltage model for novel device structure: gate electrode work function engineered recessed channel (GEWE-RC) nanoscale MOSFET, which combines the advantages of both RC and GEWE structures. In part I, the model accurately predicts (a) surface potential, (b) threshold voltage and (c) sub-threshold slope for single material gate recessed channel (SMG-RC) and GEWE-RC structures. Part II focuses on the development of compact analytical drain current model taking into account the transition regimes from sub-threshold to saturation. Furthermore, the drain conductance evaluation has also been obtained, reflecting relevance of the proposed device for analogue design. The analysis takes into account the effect of gate length and groove depth in order to develop a compact model suitable for device design. The analytical results predicted by the model confirm well with the simulated results. Results in part I also provide valuable design insights in the performance of nanoscale GEWE-RC MOSFET with optimum threshold voltage and negative junction depth (NJD), and hence serves as a tool to optimize important device and technological parameters for 40 nm technology

  11. Improved open-circuit voltage in Cu(In,Ga)Se2 solar cells with high work function transparent electrodes

    International Nuclear Information System (INIS)

    Jäger, Timo; Romanyuk, Yaroslav E.; Bissig, Benjamin; Pianezzi, Fabian; Nishiwaki, Shiro; Reinhard, Patrick; Steinhauser, Jérôme; Tiwari, Ayodhya N.; Schwenk, Johannes

    2015-01-01

    Hydrogenated indium oxide (IOH) is implemented as transparent front contact in Cu(In,Ga)Se 2 (CIGS) solar cells, leading to an open circuit voltage V OC enhanced by ∼20 mV as compared to reference devices with ZnO:Al (AZO) electrodes. This effect is reproducible in a wide range of contact sheet resistances corresponding to various IOH thicknesses. We present the detailed electrical characterization of glass/Mo/CIGS/CdS/intrinsic ZnO (i-ZnO)/transparent conductive oxide (TCO) with different IOH/AZO ratios in the front TCO contact in order to identify possible reasons for the enhanced V OC . Temperature and illumination intensity-dependent current-voltage measurements indicate that the dominant recombination path does not change when AZO is replaced by IOH, and it is mainly limited to recombination in the space charge region and at the junction interface of the solar cell. The main finding is that the introduction of even a 5 nm-thin IOH layer at the i-ZnO/TCO interface already results in a step-like increase in V OC . Two possible explanations are proposed and verified by one-dimensional simulations using the SCAPS software. First, a higher work function of IOH as compared to AZO is simulated to yield an V OC increase by 21 mV. Second, a lower defect density in the i-ZnO layer as a result of the reduced sputter damage during milder sputter-deposition of IOH can also add to a maximum enhanced V OC of 25 mV. Our results demonstrate that the proper choice of the front TCO contact can reduce the parasitic recombination and boost the efficiency of CIGS cells with improved corrosion stability

  12. Discharge amplified photo-emission from ultra-thin films applied to tuning work function of transparent electrodes in organic opto-electronic devices

    International Nuclear Information System (INIS)

    Gentle, A.R.; Smith, G.B.; Watkins, S.E.

    2013-01-01

    A novel photoemission technique utilising localised discharge amplification of photo-yield is reported. It enables fast, accurate measurement of work function and ionisation potential for ultra-thin buffer layers vacuum deposited onto single and multilayer transparent conducting electrodes for organic solar cells and OLED's. Work function in most traditional transparent electrodes has to be raised to maximise charge transfer while high transmittance and high conductance must be retained. Results are presented for a range of metal oxide buffers, which achieve this goal. This compact photo-yield spectroscopy tool with its fast turn-around has been a valuable development aid since ionisation potential can vary significantly as deposition conditions change slightly, and as ultra-thin films grow. It has also been useful in tracking the impact of different post deposition cleaning treatments along with some storage and transport protocols, which can adversely reduce ionisation potential and hence subsequent device performance.

  13. Quantum conductance of 4,4-bipyridine molecular junctions: Role of electrode work function and local d band

    DEFF Research Database (Denmark)

    Rauba, J.M.C.; Strange, Mikkel; Thygesen, Kristian Sommer

    2008-01-01

    conductance than the Pt-BPD junction due to the smaller work function of Au as compared to Pt. On the other hand, coupling to the local d band is stronger in the case of Pt and this broadens the LUMO resonance. We find that these effects largely outbalance each other leading to conductances of 0.01G(0) and 0......-principles results within a simple single-level model....

  14. Improved open-circuit voltage in Cu(In,Ga)Se{sub 2} solar cells with high work function transparent electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Jäger, Timo, E-mail: timo.jaeger@empa.ch; Romanyuk, Yaroslav E.; Bissig, Benjamin; Pianezzi, Fabian; Nishiwaki, Shiro; Reinhard, Patrick; Steinhauser, Jérôme; Tiwari, Ayodhya N. [Empa—Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Thin Films and Photovoltaics, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Schwenk, Johannes [Empa—Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Nanoscale Materials Science, Überlandstrasse 129, 8600 Dübendorf (Switzerland)

    2015-06-14

    Hydrogenated indium oxide (IOH) is implemented as transparent front contact in Cu(In,Ga)Se{sub 2} (CIGS) solar cells, leading to an open circuit voltage V{sub OC} enhanced by ∼20 mV as compared to reference devices with ZnO:Al (AZO) electrodes. This effect is reproducible in a wide range of contact sheet resistances corresponding to various IOH thicknesses. We present the detailed electrical characterization of glass/Mo/CIGS/CdS/intrinsic ZnO (i-ZnO)/transparent conductive oxide (TCO) with different IOH/AZO ratios in the front TCO contact in order to identify possible reasons for the enhanced V{sub OC}. Temperature and illumination intensity-dependent current-voltage measurements indicate that the dominant recombination path does not change when AZO is replaced by IOH, and it is mainly limited to recombination in the space charge region and at the junction interface of the solar cell. The main finding is that the introduction of even a 5 nm-thin IOH layer at the i-ZnO/TCO interface already results in a step-like increase in V{sub OC}. Two possible explanations are proposed and verified by one-dimensional simulations using the SCAPS software. First, a higher work function of IOH as compared to AZO is simulated to yield an V{sub OC} increase by 21 mV. Second, a lower defect density in the i-ZnO layer as a result of the reduced sputter damage during milder sputter-deposition of IOH can also add to a maximum enhanced V{sub OC} of 25 mV. Our results demonstrate that the proper choice of the front TCO contact can reduce the parasitic recombination and boost the efficiency of CIGS cells with improved corrosion stability.

  15. Ferrocene-functionalized graphene electrode for biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Rabti, Amal [Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona (Spain); Université de Tunis El–Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie (LR99ES15), Campus universitaire de Tunis El–Manar, 2092, Tunis (Tunisia); Mayorga-Martinez, Carmen C.; Baptista-Pires, Luis [Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona (Spain); Raouafi, Noureddine, E-mail: n.raouafi@fst.rnu.tn [Université de Tunis El–Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie (LR99ES15), Campus universitaire de Tunis El–Manar, 2092, Tunis (Tunisia); Merkoçi, Arben, E-mail: arben.merkoci@icn2.cat [Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona (Spain); ICREA, Barcelona, Catalonia (Spain)

    2016-07-05

    A novel ferrocene-functionalized reduced graphene oxide (rGO)-based electrode is proposed. It was fabricated by the drop casting of ferrocene-functionalized graphene onto polyester substrate as the working electrode integrated within screen-printed reference and counter electrodes. The ferrocene-functionalized rGO has been fully characterized using FTIR, XPS, contact angle measurements, SEM and TEM microscopy, and cyclic voltammetry. The XPS and EDX analysis showed the presence of Fe element related to the introduced ferrocene groups, which is confirmed by a clear CV signal at ca. 0.25 V vs. Ag/AgCl (0.1 KCl). Mediated redox catalysis of H{sub 2}O{sub 2} and bio-functionalization with glucose oxidase for glucose detection were achieved by the bioelectrode providing a proof for potential biosensing applications. - Graphical abstract: An easy-to-prepare standalone graphene electrode was obtained by the drop-casting ferrocene-functionalized rGO on PET polymer. This electrode can be used as an enzymeless electrochemical sensor for the detection of hydrogen peroxide or as an amperometric enzyme-based biosensor for sensitive glucose detection. - Highlights: • A novel ferrocene-functionalized reduced graphene oxide based electrode. • Ease of preparation by drop-casting of Fc-modified graphene and chitosan mixture. • Well-defined and exploitable ferrocene CV signal for sensing purposes. • Sensitive enzymeless detection of hydrogen peroxide at low potentials. • Enzymatic Sensitive detection of glucose on GOx-modified graphene electrode.

  16. Ferrocene-functionalized graphene electrode for biosensing applications

    International Nuclear Information System (INIS)

    Rabti, Amal; Mayorga-Martinez, Carmen C.; Baptista-Pires, Luis; Raouafi, Noureddine; Merkoçi, Arben

    2016-01-01

    A novel ferrocene-functionalized reduced graphene oxide (rGO)-based electrode is proposed. It was fabricated by the drop casting of ferrocene-functionalized graphene onto polyester substrate as the working electrode integrated within screen-printed reference and counter electrodes. The ferrocene-functionalized rGO has been fully characterized using FTIR, XPS, contact angle measurements, SEM and TEM microscopy, and cyclic voltammetry. The XPS and EDX analysis showed the presence of Fe element related to the introduced ferrocene groups, which is confirmed by a clear CV signal at ca. 0.25 V vs. Ag/AgCl (0.1 KCl). Mediated redox catalysis of H_2O_2 and bio-functionalization with glucose oxidase for glucose detection were achieved by the bioelectrode providing a proof for potential biosensing applications. - Graphical abstract: An easy-to-prepare standalone graphene electrode was obtained by the drop-casting ferrocene-functionalized rGO on PET polymer. This electrode can be used as an enzymeless electrochemical sensor for the detection of hydrogen peroxide or as an amperometric enzyme-based biosensor for sensitive glucose detection. - Highlights: • A novel ferrocene-functionalized reduced graphene oxide based electrode. • Ease of preparation by drop-casting of Fc-modified graphene and chitosan mixture. • Well-defined and exploitable ferrocene CV signal for sensing purposes. • Sensitive enzymeless detection of hydrogen peroxide at low potentials. • Enzymatic Sensitive detection of glucose on GOx-modified graphene electrode.

  17. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker electrode function tester. 870.3720... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is...

  18. Silver-functionalized carbon nanofiber composite electrodes for ibuprofen detection

    NARCIS (Netherlands)

    Manea, F.; Motoc, S.; Pop, A.; Remes, A.; Schoonman, J.

    2012-01-01

    The aim of this study is to prepare and characterize two types of silver-functionalized carbon nanofiber (CNF) composite electrodes, i.e., silver-decorated CNF-epoxy and silver-modified natural zeolite-CNF-epoxy composite electrodes suitable for ibuprofen detection in aqueous solution. Ag carbon

  19. Surface functional groups in capacitive deionization with porous carbon electrodes

    Science.gov (United States)

    Hemmatifar, Ali; Oyarzun, Diego I.; Palko, James W.; Hawks, Steven A.; Stadermann, Michael; Santiago, Juan G.; Stanford Microfluidics Lab Team; Lawrence Livermore National Lab Team

    2017-11-01

    Capacitive deionization (CDI) is a promising technology for removal of toxic ions and salt from water. In CDI, an applied potential of about 1 V to pairs of porous electrodes (e.g. activated carbon) induces ion electromigration and electrostatic adsorption at electrode surfaces. Immobile surface functional groups play a critical role in the type and capacity of ion adsorption, and this can dramatically change desalination performance. We here use models and experiments to study weak electrolyte surface groups which protonate and/or depropotante based on their acid/base dissociation constants and local pore pH. Net chemical surface charge and differential capacitance can thus vary during CDI operation. In this work, we present a CDI model based on weak electrolyte acid/base equilibria theory. Our model incorporates preferential cation (anion) adsorption for activated carbon with acidic (basic) surface groups. We validated our model with experiments on custom built CDI cells with a variety of functionalizations. To this end, we varied electrolyte pH and measured adsorption of individual anionic and cationic ions using inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography (IC) techniques. Our model shows good agreement with experiments and provides a framework useful in the design of CDI control schemes.

  20. Comparison of unusual carbon-based working electrodes for electrochemiluminescence sensors.

    Science.gov (United States)

    Noman, Muhammad; Sanginario, Alessandro; Jagadale, Pravin; Demarchi, Danilo; Tagliaferro, Alberto

    2017-06-01

    In this work, unconventional carbon-based materials were investigated for use in electrochemiluminescence (ECL) working electrodes. Precursors such as bamboo, pistachio shells, kevlar ® fibers and camphor were differently treated and used as working electrodes in ECL experiments. After a proper process they were assembled as electrodes and tested in an electrochemical cell. Comparison among them and with a commercial glassy carbon electrode (GCE) shows a very good response for all of them thus demonstrating their potential use as disposable low-cost electrodes for early detection electrochemical analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Work function of carburized rhenium

    International Nuclear Information System (INIS)

    Pallmer, P.G. Jr.; Gordon, R.L.; Dresser, M.J.

    1980-01-01

    Variations of the electronic work function of carburized rhenium foils containing approximately 5 at.% carbon have been observed using the contact potential difference technique. Surface work function was observed to vary between 5.25 and 4.1 eV, with the work function of pure rhenium taken as 5.0 eV. Decrease in work function has been ascribed to the formation of graphitic layers on the surface at temperatures below the temperature of saturated solubility. The high work function surface was observed with all carbon in solution and has been ascribed to the presence of amorphous carbon near the surface

  2. Renewing functionalized graphene as electrodes for high-performance supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yan [National Center for Nanoscience and Technology, Zhongguancun, Beiyitiao No.11, Beijing, 100190 (China); Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Luo, Bin; Jia, Yuying; Li, Xianglong; Wang, Bin; Song, Qi [National Center for Nanoscience and Technology, Zhongguancun, Beiyitiao No.11, Beijing, 100190 (China); Kang, Feiyu [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Zhi, Linjie [National Center for Nanoscience and Technology, Zhongguancun, Beiyitiao No.11, Beijing, 100190 (China); School of Materials Science and Engineering, University of Shanghai for Science and Technology, Jungong Road 516, 200093, Shanghai (China)

    2012-12-11

    An acid-assisted ultrarapid thermal strategy is developed for constructing specifically functionalized graphene. The electrochemical performance of functionalized graphene can be boosted via elaborate coupling between the pseudocapacitance and the electronic double layer capacitance through rationally tailoring the structure of graphene sheets. This presents an opportunity for developing further high-performance graphene-based electrodes to bridge the performance gap between traditional capacitors and batteries. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Renewing functionalized graphene as electrodes for high-performance supercapacitors.

    Science.gov (United States)

    Fang, Yan; Luo, Bin; Jia, Yuying; Li, Xianglong; Wang, Bin; Song, Qi; Kang, Feiyu; Zhi, Linjie

    2012-12-11

    An acid-assisted ultrarapid thermal strategy is developed for constructing specifically functionalized graphene. The electrochemical performance of functionalized graphene can be boosted via elaborate coupling between the pseudocapacitance and the electronic double layer capacitance through rationally tailoring the structure of graphene sheets. This presents an opportunity for developing further high-performance graphene-based electrodes to bridge the performance gap between traditional capacitors and batteries. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Characterisation of work function fluctuations for high-precision experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kahlenberg, Jan; Bickmann, Edward; Heil, Werner; Otten, Ernst W.; Schmidt, Christian; Wunderle, Alexander [Johannes Gutenberg-Universitaet Mainz (Germany); Babutzka, Martin; Schoenung, Kerstin [Karlsruher Institut fuer Technologie (Germany); Beck, Marcus [Johannes Gutenberg-Universitaet Mainz (Germany); Helmholtz-Institut Mainz (Germany)

    2016-07-01

    For a wide range of high-precision experiments in physics, well-defined electric potentials for achieving high measurement accuracies are required. An accurate determination of the electric potential is crucial for the measurement of the neutrino mass (KATRIN) as well as the measurement of the e{sup -} anti ν{sub e} correlation coefficient a in free neutron decay (aSPECT). Work function fluctuations on the electrodes lead to uncertainties in the distribution of the electric potential. For aSPECT, the electric potential has to be known at an accuracy of 10 mV. However, due to the patch effect of gold, work function fluctuations of several 100 meV can occur. Therefore, the work function distributions of the gold-plated electrodes have been measured using a Kelvin probe. Furthermore, the change of work function distributions over time as well as the influence of relative humidity on the work function measurement have been investigated. For aSPECT, the work function distributions of the gold-plated electrodes have been measured using a Kelvin probe. Due to the patch effect of gold, work function fluctuations of up to 160 meV occur. This would lead to a significant uncertainty of the potential barrier, which should be known at an accuracy of 10 mV. Furthermore, the change of work function distributions over time as well as the influence of relative humidity on the work function measurement have been investigated.

  5. Carbon nanotubes functionalized by salts containing stereogenic heteroatoms as electrodes in their battery cells

    OpenAIRE

    Zdanowska Sandra; Pyzalska Magdalena; Drabowicz Józef; Kulawik Damian; Pavlyuk Volodymyr; Girek Tomasz; Ciesielski Wojciech

    2016-01-01

    This paper concentrates on electrochemical properties of groups of multi-walled carbon nanotubes (MWCNT) functionalized with substituents containing a stereogenic heteroatom bonded covalently to the surface of the carbon nanotube. This system was tested in Swagelok-type cells. The cells comprised a system (functionalized CNT with salts containing S and P atoms) with a working electrode, microfiber separators soaked with electrolyte solution, and a lithium foil counter/reference (commercial Li...

  6. Working electrodes from amalgam paste for electrochemical measurements

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Bohdan; Šestáková, Ivana

    2008-01-01

    Roč. 20, č. 4 (2008), s. 426-433 ISSN 1040-0397 R&D Projects: GA ČR GA203/07/1195; GA ČR GA521/06/0496 Institutional research plan: CEZ:AV0Z40400503 Keywords : voltammetry * paste amalgam * silver amalgam * paste electrode Subject RIV: CG - Electrochemistry Impact factor: 2.901, year: 2008

  7. Carbon nanotubes functionalized by salts containing stereogenic heteroatoms as electrodes in their battery cells

    Directory of Open Access Journals (Sweden)

    Zdanowska Sandra

    2016-12-01

    Full Text Available This paper concentrates on electrochemical properties of groups of multi-walled carbon nanotubes (MWCNT functionalized with substituents containing a stereogenic heteroatom bonded covalently to the surface of the carbon nanotube. This system was tested in Swagelok-type cells. The cells comprised a system (functionalized CNT with salts containing S and P atoms with a working electrode, microfiber separators soaked with electrolyte solution, and a lithium foil counter/reference (commercial LiCoO2 electrode. The electrolyte solution was 1 M LiPF6 in propylene carbonate. Using standard techniques (cyclic voltammetry/chronopotentiometry, galvanostatic cycling was performed on the cells at room temperature with a CH Instruments Model 600E potentiostat/galvanostat electrochemical measurements. Methods of functionalization CNT were compared in terms of the electrochemical properties of the studied systems. In all systems, the process of charge/discharge was observed.

  8. Tuning of metal work functions with self-assembled monolayers

    NARCIS (Netherlands)

    de Boer, B; Hadipour, A; Mandoc, MM; van Woudenbergh, T; Blom, PWM

    2005-01-01

    Work functions of gold and silver are varied by over 1.4 and 1.7 eV, respectively, by using self-assembled monolayers. Using these modified electrodes, the hole current in a poly(2-methoxy-5-(2'-ethylhexyloxy)- 1,4-phenylene vinylene) light-emitting diode is tuned by more than six orders of

  9. In-situ thermoelectrochemistry working with heated electrodes

    CERN Document Server

    Gründler, Peter

    2015-01-01

    This book represents the first rigorous treatment of thermoelectrochemistry, providing an overview that will stimulate electrochemists to develop and apply modern thermoelectrochemical methods. While classical static approaches are also covered, the emphasis lies on methods that make it possible to independently vary temperature such as in-situ heating of electrodes by means of electric current, microwaves or lasers. For the first time, "hot-wire electrochemistry" is examined in detail. The theoretical background presented addresses all aspects of temperature impacts in the context of electroc

  10. Near-Electrode Imager

    Energy Technology Data Exchange (ETDEWEB)

    Rathke, Jerome W.; Klingler, Robert J.; Woelk, Klaus; Gerald, Rex E.,II

    1999-05-01

    An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager use the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.

  11. Nickel electrodes as a cheap and versatile platform for studying structure and function of immobilized redox proteins

    Energy Technology Data Exchange (ETDEWEB)

    Han, Xiao Xia [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Li, Junbo [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Öner, Ibrahim Halil [Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Zhao, Bing [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Leimkühler, Silke [Institut für Biochemie und Biologie, Universität Potsdam, Karl-Liebknecht Straße 24-25, H. 25, Golm D-14476 (Germany); Hildebrandt, Peter [Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany); Weidinger, Inez M., E-mail: i.weidinger@mailbox.tu-berlin.de [Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin (Germany)

    2016-10-19

    Practical use of many bioelectronic and bioanalytical devices is limited by the need of expensive materials and time consuming fabrication. Here we demonstrate the use of nickel electrodes as a simple and cheap solid support material for bioelectronic applications. The naturally nanostructured electrodes showed a surprisingly high electromagnetic surface enhancement upon light illumination such that immobilization and electron transfer reactions of the model redox proteins cytochrome b{sub 5} (Cyt b{sub 5}) and cytochrome c (Cyt c) could be followed via surface enhanced resonance Raman spectroscopy. It could be shown that the nickel surface, when used as received, promotes a very efficient binding of the proteins upon preservation of their native structure. The immobilized redox proteins could efficiently exchange electrons with the electrode and could even act as an electron relay between the electrode and solubilized myoglobin. Our results open up new possibility for nickel electrodes as an exceptional good support for bioelectronic devices and biosensors on the one hand and for surface enhanced spectroscopic investigations on the other hand. - Highlights: • Nickel electrodes were used without further functionalization as supports for various redox proteins. • It was possible to monitor the immobilized proteins via surface enhanced Raman spectroscopy. • The native structure of the immobilized proteins was preserved and they could exchange electrons with the Ni electrode. • The immobilized redox proteins worked as an electron relay between electrode and solubilized myoglobin.

  12. Dithiocarbamate Self-Assembled Monolayers as Efficient Surface Modifiers for Low Work Function Noble Metals

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Dominik; Schäfer, Tobias; Schulz, Philip; Jung, Sebastian; Rittich, Julia; Mokros, Daniel; Segger, Ingolf; Maercks, Franziska; Effertz, Christian; Mazzarello, Riccardo; Wuttig, Matthias

    2016-09-06

    Tuning the work function of the electrode is one of the crucial steps to improve charge extraction in organic electronic devices. Here, we show that N,N-dialkyl dithiocarbamates (DTC) can be effectively employed to produce low work function noble metal electrodes. Work functions between 3.1 and 3.5 eV are observed for all metals investigated (Cu, Ag, and Au). Ultraviolet photoemission spectroscopy (UPS) reveals a maximum decrease in work function by 2.1 eV as compared to the bare metal surface. Electronic structure calculations elucidate how the complex interplay between intrinsic dipoles and dipoles induced by bond formation generates such large work function shifts. Subsequently, we quantify the improvement in contact resistance of organic thin film transistor devices with DTC coated source and drain electrodes. These findings demonstrate that DTC molecules can be employed as universal surface modifiers to produce stable electrodes for electron injection in high performance hybrid organic optoelectronics.

  13. Potentiometric detection of silver (I) ion based on carbon paste electrode modified with diazo-thiophenol-functionalized nanoporous silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ting; Chai Yaqin, E-mail: yqchai@swu.edu.cn; Yuan Ruo; Guo Junxiang

    2012-07-01

    For the first time, triazene compound functionalized silica gel was incorporated into carbon paste electrode for the potentiometric detection of silver (I) ion. A novel diazo-thiophenol-functionalized silica gel (DTPSG) was synthesized, and the presence of DTPSG acted as not only a paste binder, but also a reactive material. The electrode with optimum composition, exhibited an excellent Nernstian response to Ag{sup +} ion ranging from 1.0 Multiplication-Sign 10{sup -6} to 1.0 Multiplication-Sign 10{sup -1} M with a detection limit of 9.5 Multiplication-Sign 10{sup -7} M and a slope of 60.4 {+-} 0.2 mV dec{sup -1} over a wide pH range (4.0-9.0) with a fast response time (50 s) at 25 Degree-Sign C. The electrode also showed a long-time stability, high selectivity and reproducibility. The response mechanism of the proposed electrode was investigated by using AC impedance. Moreover, the electrode was successfully applied for the determination of silver ions in radiology films, and for potentiometric titration of the mixture solution of Cl{sup -} and Br{sup -} ions. - Highlights: Black-Right-Pointing-Pointer Functionalized silica gels have become promising materials. Black-Right-Pointing-Pointer This work is the first attempt to apply triazene functionalized silica gel. Black-Right-Pointing-Pointer The Functionalized silica gels were used to detect silver. Black-Right-Pointing-Pointer The response of the previously reported papers are compared with this work. Black-Right-Pointing-Pointer The result indicates the proposed electrode is better than reported Ag{sup +} electrodes.

  14. Potentiometric detection of silver (I) ion based on carbon paste electrode modified with diazo-thiophenol-functionalized nanoporous silica gel

    International Nuclear Information System (INIS)

    Zhang Ting; Chai Yaqin; Yuan Ruo; Guo Junxiang

    2012-01-01

    For the first time, triazene compound functionalized silica gel was incorporated into carbon paste electrode for the potentiometric detection of silver (I) ion. A novel diazo-thiophenol-functionalized silica gel (DTPSG) was synthesized, and the presence of DTPSG acted as not only a paste binder, but also a reactive material. The electrode with optimum composition, exhibited an excellent Nernstian response to Ag + ion ranging from 1.0 × 10 −6 to 1.0 × 10 −1 M with a detection limit of 9.5 × 10 −7 M and a slope of 60.4 ± 0.2 mV dec −1 over a wide pH range (4.0–9.0) with a fast response time (50 s) at 25 °C. The electrode also showed a long-time stability, high selectivity and reproducibility. The response mechanism of the proposed electrode was investigated by using AC impedance. Moreover, the electrode was successfully applied for the determination of silver ions in radiology films, and for potentiometric titration of the mixture solution of Cl − and Br − ions. - Highlights: ► Functionalized silica gels have become promising materials. ► This work is the first attempt to apply triazene functionalized silica gel. ► The Functionalized silica gels were used to detect silver. ► The response of the previously reported papers are compared with this work. ► The result indicates the proposed electrode is better than reported Ag + electrodes.

  15. Standard hydrogen electrode and potential of zero charge in density functional calculations

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Björketun, Mårten; Skúlason, Egill

    2011-01-01

    standard hydrogen electrode potential (ASHEP) from the calculated work function. Although conceptually correct, this procedure introduces two sources of errors: (i) the experimental estimate of the ASHEP varies from 4.28 to 4.85 V and, as has been previously shown and is reconfirmed here, (ii...... possess in order for its computed ASHEP to closely match the experimental benchmark. We capture and quantify these three effects by calculating trends in the ASHEP and PZC on eight close-packed transition metals, considering the four most simple and representative water models. Finally, it is also...

  16. Nanostructured membranes and electrodes with sulfonic acid functionalized carbon nanotubes

    KAUST Repository

    Tripathi, Bijay Prakash; Schieda, Mauricio; Shahi, Vinod Kumar; Nunes, Suzana Pereira

    2011-01-01

    Herein we report the covalent functionalization of multiwall carbon nanotubes by grafting sulfanilic acid and their dispersion into sulfonated poly(ether ether ketone). The nanocomposites were explored as an option for tuning the proton and electron conductivity, swelling, water and alcohol permeability aiming at nanostructured membranes and electrodes for application in alcohol or hydrogen fuel cells and other electrochemical devices. The nanocomposites were extensively characterized, by studying their physicochemical and electrochemical properties. They were processed as self-supporting films with high mechanical stability, proton conductivity of 4.47 × 10 -2 S cm-1 at 30 °C and 16.8 × 10-2 S cm-1 at 80 °C and 100% humidity level, electron conductivity much higher than for the plain polymer. The methanol permeability could be reduced to 1/20, keeping water permeability at reasonable values. The ratio of bound water also increases with increasing content of sulfonated filler, helping in keeping water in the polymer in conditions of low external humidity level. © 2010 Elsevier B.V.

  17. Nanostructured membranes and electrodes with sulfonic acid functionalized carbon nanotubes

    KAUST Repository

    Tripathi, Bijay Prakash

    2011-02-01

    Herein we report the covalent functionalization of multiwall carbon nanotubes by grafting sulfanilic acid and their dispersion into sulfonated poly(ether ether ketone). The nanocomposites were explored as an option for tuning the proton and electron conductivity, swelling, water and alcohol permeability aiming at nanostructured membranes and electrodes for application in alcohol or hydrogen fuel cells and other electrochemical devices. The nanocomposites were extensively characterized, by studying their physicochemical and electrochemical properties. They were processed as self-supporting films with high mechanical stability, proton conductivity of 4.47 × 10 -2 S cm-1 at 30 °C and 16.8 × 10-2 S cm-1 at 80 °C and 100% humidity level, electron conductivity much higher than for the plain polymer. The methanol permeability could be reduced to 1/20, keeping water permeability at reasonable values. The ratio of bound water also increases with increasing content of sulfonated filler, helping in keeping water in the polymer in conditions of low external humidity level. © 2010 Elsevier B.V.

  18. Functional fusion of living systems with synthetic electrode interfaces

    Directory of Open Access Journals (Sweden)

    Oskar Staufer

    2016-02-01

    Full Text Available The functional fusion of “living” biomaterial (such as cells with synthetic systems has developed into a principal ambition for various scientific disciplines. In particular, emerging fields such as bionics and nanomedicine integrate advanced nanomaterials with biomolecules, cells and organisms in order to develop novel strategies for applications, including energy production or real-time diagnostics utilizing biomolecular machineries “perfected” during billion years of evolution. To date, hardware–wetware interfaces that sample or modulate bioelectric potentials, such as neuroprostheses or implantable energy harvesters, are mostly based on microelectrodes brought into the closest possible contact with the targeted cells. Recently, the possibility of using electrochemical gradients of the inner ear for technical applications was demonstrated using implanted electrodes, where 1.12 nW of electrical power was harvested from the guinea pig endocochlear potential for up to 5 h (Mercier, P.; Lysaght, A.; Bandyopadhyay, S.; Chandrakasan, A.; Stankovic, K. Nat. Biotech. 2012, 30, 1240–1243. More recent approaches employ nanowires (NWs able to penetrate the cellular membrane and to record extra- and intracellular electrical signals, in some cases with subcellular resolution (Spira, M.; Hai, A. Nat. Nano. 2013, 8, 83–94. Such techniques include nanoelectric scaffolds containing free-standing silicon NWs (Robinson, J. T.; Jorgolli, M.; Shalek, A. K.; Yoon, M. H.; Gertner, R. S.; Park, H. Nat Nanotechnol. 2012, 10, 180–184 or NW field-effect transistors (Qing, Q.; Jiang, Z.; Xu, L.; Gao, R.; Mai, L.; Lieber, C. Nat. Nano. 2013, 9, 142–147, vertically aligned gallium phosphide NWs (Hällström, W.; Mårtensson, T.; Prinz, C.; Gustavsson, P.; Montelius, L.; Samuelson, L.; Kanje, M. Nano Lett. 2007, 7, 2960–2965 or individually contacted, electrically active carbon nanofibers. The latter of these approaches is capable of recording

  19. Functions of chalcogenide electrodes in solutions of complexing reagents and interfering ions

    International Nuclear Information System (INIS)

    Kiyanskij, V.V.

    1990-01-01

    The possibility to modify chalcogenide electrodes and their behaviour in solutions of complexing reagents for the development of new methods of potentiometric titration has been studied. It is shown that complexing reagents (EDTA, cupferron, 8-hydroxyquinoline, sodium dithiocarbaminate) and Cu(2), Hg(2) produce a strong effect on the functions of Ag, Cu, Cd, Pb - selective electrodes, which is used for titration of potential-determining and non-potential-determining ions ions (Sr 2+ , La 3+ etc.) and also for modification of sulfide-selecting electrode. A method of potentiometric titration of sulfates and chlorides with modified Cd- and Ag-selective electrodes is suggested

  20. Electrochemical studies of Pu on prussian blue (PB)-gold nanoparticles (AuNPs) functionalized glassy carbon (GC) electrode

    International Nuclear Information System (INIS)

    Sharma, Manoj K.; Ambolikar, Arvind S.; Aggarwal, Suresh K.

    2011-01-01

    In electrochemical processes, electron transfer across the solid-liquid interface is the elementary step and electron transfer kinetics is significantly influenced by the interfacial properties. Therefore, preparation of well-defined electrochemical interface with highly controllable properties - larger effective surface area, increased mass transport, and better electronic interaction between the analyte and electrode - is significant for both fundamental and applied studies in electrochemistry. In the present work electrochemistry of Pu(IV)/Pu(III) is studied on multilayered AuNPs-PB-AuNPs functionalized electrode

  1. Functionalization of niobium electrodes for the construction of impedimetric biosensors

    International Nuclear Information System (INIS)

    Helali, S.; Abdelghani, A.; Hafaiedh, I.; Martelet, C.; Prodromidis, M.I.; Albanis, T.; Jaffrezic-Renault, N.

    2008-01-01

    This paper describes the development of an impedimetric immunosensor, based on niobium/niobium oxide (Nb/NbOxHy) electrodes, for the detection of atrazine. Niobium oxide was anodically formed onto niobium electrodes at 25 V in 1 M H 2 SO 4 . Hydrous oxide layers were then silanized with APTES, and using glutaraldehyde as a cross linker, Fab fragment k47 antibody was covalently immobilized onto the surface of the electrodes. Electrochemical impedance spectroscopy (EIS) was used to characterize the building-up of the immunosensors as well as the binding of atrazine to its specific antibody. In presence of ferricyanide redox species and under a cathodic polarization voltage (- 1.2 V versus SCE), the relationship between the concentration of atrazine and the change of the electron transfer resistance value was studied

  2. A multi-pad electrode based functional electrical stimulation system for restoration of grasp

    Directory of Open Access Journals (Sweden)

    Malešević Nebojša M

    2012-09-01

    Full Text Available Abstract Background Functional electrical stimulation (FES applied via transcutaneous electrodes is a common rehabilitation technique for assisting grasp in patients with central nervous system lesions. To improve the stimulation effectiveness of conventional FES, we introduce multi-pad electrodes and a new stimulation paradigm. Methods The new FES system comprises an electrode composed of small pads that can be activated individually. This electrode allows the targeting of motoneurons that activate synergistic muscles and produce a functional movement. The new stimulation paradigm allows asynchronous activation of motoneurons and provides controlled spatial distribution of the electrical charge that is delivered to the motoneurons. We developed an automated technique for the determination of the preferred electrode based on a cost function that considers the required movement of the fingers and the stabilization of the wrist joint. The data used within the cost function come from a sensorized garment that is easy to implement and does not require calibration. The design of the system also includes the possibility for fine-tuning and adaptation with a manually controllable interface. Results The device was tested on three stroke patients. The results show that the multi-pad electrodes provide the desired level of selectivity and can be used for generating a functional grasp. The results also show that the procedure, when performed on a specific user, results in the preferred electrode configuration characteristics for that patient. The findings from this study are of importance for the application of transcutaneous stimulation in the clinical and home environments.

  3. Ion-selective electrodes in organic elemental and functional group analysis: a review

    International Nuclear Information System (INIS)

    Selig, W.

    1977-01-01

    The literature on the use of ion-selective electrodes in organic elemental and functional group analysis is surveyed in some detail. The survey is complete through Chemical Abstracts, Vol. 83 (1975). 40 figures, 52 tables, 236 references

  4. Ion-selective electrodes in organic elemental and functional group analysis: a review

    Energy Technology Data Exchange (ETDEWEB)

    Selig, W.

    1977-11-08

    The literature on the use of ion-selective electrodes in organic elemental and functional group analysis is surveyed in some detail. The survey is complete through Chemical Abstracts, Vol. 83 (1975). 40 figures, 52 tables, 236 references.

  5. A selective iodide ion sensor electrode based on functionalized ZnO nanotubes.

    Science.gov (United States)

    Ibupoto, Zafar Hussain; Khun, Kimleang; Willander, Magnus

    2013-02-04

    In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF) was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10-6 to 1 × 10-1 M) and excellent sensitivity of -62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10-7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

  6. A Selective Iodide Ion Sensor Electrode Based on Functionalized ZnO Nanotubes

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2013-02-01

    Full Text Available In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10−6 to 1 × 10−1 M and excellent sensitivity of –62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10−7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

  7. Sample preparation and electrochemical data of Co3O4 working electrode for seawater splitting

    Directory of Open Access Journals (Sweden)

    Malkeshkumar Patel

    2017-10-01

    Full Text Available In this data article, we presented the electrochemical data of the working electrode made of Co3O4 semi-transparent film. Electrochemically stable, porous nature of Kirkendall-diffusion grown Co3O4 films were applied to generate hydrogen from the seawater splitting (Patel et al., 2017 [1]. The data presented in this article includes the photograph of prepared samples, polarization curves for water oxidation and Tafel plot, linear sweep voltammetry measurements under the pulsed light condition in 0.1 M Na2S2O3 electrolyte, and transient photoresponses with natural sea water. Moreover, seawater splitting using the Co3O4 working electrode is demonstrated.

  8. Mahlburg's Work on Crank Functions

    Indian Academy of Sciences (India)

    IAS Admin

    640–651, 2006. [8]. G N Watson, Ramanujan's Vermutung uber zerfallungsanzahlen, J. Reine Angew Math., Vol.179, pp.97–128, 1938. [9]. J Lehner, Ramanujan identities involving the partition function for the moduli 11α, Amer. J. Math.

  9. Enhanced luminol electrochemiluminescence triggered by an electrode functionalized with dendrimers modified with titanate nanotubes

    International Nuclear Information System (INIS)

    Lin, Yanyu; Yang, Yusheng; Dai, Hong; Xu, Guifang; Yang, Ting; Tong, Yuejin; Yang, Caiping; Chen, Guonan

    2013-01-01

    We have constructed a novel electro chemiluminescence (ECL) platform by functionalizing a poly(amidoamine) dendrimer (PAAD) with titanate nanotubes (TiNTs). The PAAD has an open spherical structure that possesses a high density of active groups and thus favors mass transport, while the TiNTs possess excellent electronic conductivity and thus can promote electron transfer on the surface of a glassy carbon electrode (GCE). A study on the intensity and stability of the ECL of luminol on the modified GCE revealed a substantial improvement compared to that of a bare GCE. The effects of the concentration of TiNTs, the pH value of the solution, and of electrochemical parameters on the intensity of the ECL of luminol were studied and resulted in a sensitive ECL sensor for hydrogen peroxide (H 2 O 2 ) that works in the concentration range of 1 nM to 0.9 μM. The scavenging effect of superoxide dismutase (SOD) on the H 2 O 2 electrode ECL was then exploited to design a biosensor for the determination of SOD in concentrations between 50 and 500 nM. (author)

  10. Direct chronopotentiometric analysis of riboflavin using a glassy carbon vessel as the working electrode

    Directory of Open Access Journals (Sweden)

    Brezo Tanja Ž.

    2016-01-01

    Full Text Available A new method for the determination of riboflavin (vitamin B2 was developed based on chronopotentiometry with a glassy carbon process vessel macroelectrode. The method optimisation included investigation of the most important experimental parameters: type and concentration of the supporting electrolyte, initial potential, reduction current, and the working electrode surface area. The reduction signal of riboflavin appeared at about -0.12 V vs. Ag/AgCl (3.5 mol/dm3 KCl electrode in 0.025 mol/dm3 HCl as the supporting electrolyte. A linear response was obtained in the the range of 0.05-4 mg/dm3. The limit of detection and limit of quantitation were 0.018 mg/dm3 and 0.054 mg/dm3, respectively. Due to the use of specific working electrode, a significant enhancement of the method relative sensitivity of about 10 times was achieved. The accuracy of the defined method was confirmed by HPLC analyses. The developed method was successfully applied for the quantitation of riboflavin in various pharmaceutical multivitamin preparations. [Projekat Ministarstva nauke Republike Srbije, br. III 46009

  11. Functional materials in amperometric sensing polymeric, inorganic, and nanocomposite materials for modified electrodes

    CERN Document Server

    Seeber, Renato; Zanardi, Chiara

    2014-01-01

    Amperometric sensors, biosensors included, particularly rely on suitable electrode materials. Progress in material science has led to a wide variety of options that are available today. For the first time, these novel functional electrode coating materials are reviewed in this monograph, written by and for electroanalytical chemists. This includes intrinsically conducting, redox and ion-exchange polymers, metal and carbon nanostructures, silica based materials. Monolayers and relatively thick films are considered. The authors critically discuss preparation methods, in addition to chemical and

  12. Analytical expression for the tunnel current through the redox-mediated tunneling contact in the case of the adiabatic electron transfer at one of the working electrodes and any possible type of the electron transfer at the other electrode.

    Science.gov (United States)

    Medvedev, Igor G

    2017-11-21

    We study the tunnel current through a one-level redox molecule immersed into the electrolyte solution for the case when the coupling of the molecule to one of the working electrodes is strong while it is arbitrary to the other electrode. Using the Feynman-Vernon influence functional theory and the perturbation expansion of the effective action of the classical oscillator coupled both to the valence level of the redox molecule and to the thermal bath representing the classical fluctuations of the polarization of the solvent, we obtain, following the canonical way, the Langevin equation for the oscillator. It is found that for the aqueous electrolyte solution, the damping and the stochastic forces which arise due to the tunnel current are much smaller than those due to the thermal bath and therefore can be neglected. We estimate the higher-order corrections to the effective action and show that the Langevin dynamics takes place in this case for arbitrary parameters of the tunneling junction under the condition of the strong coupling of the redox molecule to one of the working electrodes. Then the steady-state coordinate distribution function of the oscillator resulting from the corresponding Fokker-Planck equation is the Boltzmann distribution function which is determined by the adiabatic free energy surface arising from the mean current-induced force. It enables us to obtain the expression for the tunnel current in the case when the coupling of the redox molecule to one of the working electrodes is strong while it is arbitrary to the other electrode.

  13. Influence of thin film thickness of working electrodes on photovoltaic characteristics of dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Lai Yeong-Lin

    2017-01-01

    Full Text Available This paper presents the study of the influence of thin film thickness of working electrodes on the photovoltaic characteristics of dye-sensitized solar cells. Titanium dioxide (TiO2 thin films, with the thickness from 7.67 to 24.3 μm, were used to fabricate the working electrodes of dye-sensitized solar cells (DSSCs. A TiO2 film was coated on a fluorine-doped tin oxide (FTO conductive glass substrate and then sintered in a high-temperature furnace. On the other hand, platinum (Pt solution was coated onto an FTO substrate for the fabrication of the counter electrode of a DSSC. The working electrode immersed in a dye, the counter electrode, and the electrolyte were assembled to complete a sandwich-structure DSSC. The material analysis of the TiO2 films of DSSCs was carried out by scanning electron microscopy (SEM and ultraviolet-visible (UV-Vis spectroscopy, while the photovoltaic characteristics of DSSCs were measured by an AM-1.5 sunlight simulator. The light transmittance characteristics of the TiO2 working electrode depend on the TiO2 film thickness. The thin film thickness of the working electrode also affects the light absorption of a dye and results in the photovoltaic characteristics of the DSSC, including open-circuited voltage (VOC, short-circuited current density (JSC, fill factor, and photovoltaic conversion efficiency.

  14. Vestibular Function After Cochlear Implantation: A Comparison of Three Types of Electrodes.

    Science.gov (United States)

    Frodlund, Jonas; Harder, Henrik; Mäki-Torkko, Elina; Ledin, Torbjörn

    2016-12-01

    To investigate the vestibular function after cochlear implantation with different types of electrode arrays. Retrospective cohort study. Academic tertiary referral center. Forty three adults underwent first cochlear implantation. Three consecutive series of patients: Group 1 (n = 13) implanted with a precurved electrode, Group 2 (n = 15) implanted with a straight electrode, Group 3 (n = 15) implanted with a flexible electrode. Patient's vestibular functions were assessed with pre- and postoperative caloric testing using videonystagmography (VNG). The postoperative reduction of the maximum slow phase velocity (MSPV) in the implanted ear was evaluated. Medical charts were reviewed to evaluate the occurrence of late onset of postoperative vestibular symptoms. Mean reduction of MSPV was 7.6/s (standard deviation [SD] 8.0) in Group 1, 23.1/s (SD 16.6) in Group 2, and 0.1/s (SD 18.5) in Group 3. Significant difference was found between Group 1 and 2 (p < 0.030) and between Group 2 and 3 (p < 0.001). Group 2 showed a higher prevalence of late onset of clinical vertigo (28.6%) than Group 1 (7.7%) and 3 (6.7%). In this prospective study, significantly larger reductions of caloric responses were found in subjects implanted with a straight electrode compared with subjects implanted with a precurved or flexible electrode. These findings seem to correlate to a higher prevalence of postoperative vertigo.

  15. Intrinsic work function of molecular films

    International Nuclear Information System (INIS)

    Ivančo, Ján

    2012-01-01

    The electronic properties of molecular films are analysed with the consideration of the molecular orientation. The study demonstrates that surfaces of electroactive oligomeric molecular films can be classified—analogously to the elemental surfaces—by their intrinsic work functions. The intrinsic work function of molecular films is correlated with their ionisation energies; again, the behaviour is analogous to the correlation existing between the first ionisation energy of elements and the work function of the corresponding elemental surfaces. The proposed intrinsic work-function concept suggests that the mechanism for the energy-level alignment at the interfaces associated with molecular films is virtually controlled by work functions of materials brought into the contact. - Highlights: ► Molecular films exhibit their own (intrinsic) work function. ► Intrinsic work function is correlated with ionisation energy of molecular films. ► Intrinsic work function determines dipole at interface with a particular surface. ► Surface vacuum-level change upon film growth does not relate to interfacial dipole.

  16. Functionalized Nanoporous Track Etched {beta}-PVDF Membrane Electrodes for Lead (II) Determination by Square Wave Anodic Stripping Voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Bessbousse, H [Laboratoire des Solides Irradies, CEA-CNRS-Ecole Polytechnique, 91128 Palaiseau (France); Nadhakumar, I [School of Chemistry, University of Southampton, University Road, Southampton S017 1BJ (United Kingdom); Decker, M; Clochard, M -C; Wade, T L [Laboratoire des Solides Irradies, CEA-CNRS-Ecole Polytechnique, 91128 Palaiseau (France); Barsbay, M [Hacettepe University, Department of Chemistry, Polymer Chemistry Division, 06800 Beytepe Ankara (Turkey)

    2012-09-15

    Track etched functionalized nanoporous {beta}-PVDF membrane electrodes, or functionalized membrane electrodes (FME), are thin-layer cells made from poly(acrylic acid) (PAA) functionalized nanoporous {beta}-poly(vinylidene fluoride) ({beta}-PVDF) membranes with thin Au films sputtered on each side as electrodes. The Au film is thin enough that the pores of the membranes are not completely covered. The PAA functionalization is specifically localised in the walls of the nanoporous {beta}-PVDF membrane by grafting. The PAA is a cation exchange polymer that adsorbs metal ions, such as Pb{sup 2+}, from aqueous solutions concentrating the ions into the membrane. After a time the FME is transferred to an electrochemical cell for analysis. A negative potential is applied to the Au film of the FME for a set time to reduce the adsorbed ions onto the Au film working electrode. The other metalized side of the FME functions as a counter electrode. Finally, square-wave anodic stripping voltammetry (SW-ASV) is performed on the FME to determine the metal ion concentrations in the original solution. The calibration curve of charge versus log concentration has a Temkin isotherm form. The FME membranes are 9 {mu}m thick and have 40 nm diameter pores with a density of 10{sup 10} pores/cm{sup 2}. This high pore density provides a large capacity for ion adsorption. Au ingress in the pores during sputtering forms a random array of nanoelectrodes. Like surface modified electrodes for adsorptive stripping voltammetry, the pre-concentration step for the FME is performed at open circuit. The zero current intercept of the calibration for Pb{sup 2+} is 0.13 ppb ({mu}g/L) and a detection limit of 0.050 ppb based on 3S/N from blank measurements. Voltammetry (CV) and chronoapmerometry (CA) were used to characterize the system. The apparent diffusion coefficient (D) for Pb{sup 2+} in the PAA functionalized pores was determined to be 2.44 x 10{sup -7} cm{sup 2}/s and the partition coefficient (p

  17. Chemical attachment of functionalized multiwalled carbon nanotubes on glassy carbon electrode for electrocatalytic application

    International Nuclear Information System (INIS)

    Rajalakshmi, K.; Abraham John, S.

    2015-01-01

    Highlights: • FMWCNTs were covalently attached on GC surface with the aid of alkyldiamine. • The attached FMWCNTs were stable for a wide potential window due to the robust C−N bond. • The composite electrode was prepared by electropolymerizing thiadiazole on FMWCNTs. • The detection limit of 0.27 μM (S/N = 3) of GMP was achieved using composite modified electrode. - Abstract: The covalent attachment of acid functionalized multiwalled carbon nanotubes (FMWCNTs) on glassy carbon (GC) electrode using 1,8-octanediamine (OD) as a linker via carbodiimide chemistry was described. The attachment of FMWCNTs on GC electrode were confirmed by attenuated total reflectance Fourier transform infra-red (ATR-FT-IR) spectroscopy, Raman, scanning electron microscopy (SEM) and electrochemical impedance studies. Raman spectrum of FMWCNTs modified surface shows the characteristic G and D bands at 1563 cm −1 and 1340 cm −1 , respectively. This confirmed the successful attachment of FMWCNTs on the OD modified GC surface. Further, the attachment of FMWCNTs on OD modified surface via amide linkage was confirmed from the observed characteristic peak at 1681 cm −1 in the ATR-FT-IR spectrum. The SEM images showed that the covalently attached FMWCNTs retained their morphology similar to powder and the average diameter of them was found to be 58 nm. Unlike modification of FMWCNTs on gold substrates with the aid of conventional thiol linkers (Au−S bond), modification of them by the present method was stable for a wide positive potential window due to the robust C−N bond. To demonstrate the electrochemical stability of the MWCNTs modified electrode at more positive potential, guanosine 5′-monophosphate (GMP) was selected as a representative probe because its oxidation occurs at more than 1 V. It was found that the FMWCNTs modified electrode not only showed a stable signal for GMP but also enhanced its oxidation current when compared to bare GC electrode. Further, the

  18. Electrochemical functionalization of glassy carbon electrode by reduction of diazonium cations in protic ionic liquid

    International Nuclear Information System (INIS)

    Shul, Galyna; Ruiz, Carlos Alberto Castro; Rochefort, Dominic; Brooksby, Paula A.; Bélanger, Daniel

    2013-01-01

    Protic ionic liquid based on 2-methoxypyridine and trifluoroacetic acid was used as electrolyte for the functionalization of a glassy carbon electrode surface by electrochemical reduction of in situ generated 4-chlorobenzene diazonium and 4-nitrobenzene diazonium cations. The diazonium cations were synthesized in an electrochemical cell by reaction of the corresponding amines with NaNO 2 dissolved in protic ionic liquid. The resulting electrografted organic layers exhibit similar properties to those layers obtained by the derivatization from isolated diazonium salts dissolved in protic ionic liquid. Functionalized glassy carbon electrode surfaces were characterized by cyclic voltammetry, Fourier transform infrared and X-ray photoelectron spectroscopies. Atomic force microscopy thickness measurements revealed that, in our experimental conditions, the use of protic ionic liquid led to the formation of film with a thickness of about 1.5 nm. It is also demonstrated that the nitrobenzene chemisorbed on glassy carbon electrode or dissolved in protic ionic liquid undergoes electrochemical conversion to hydroxyaminobenzene

  19. Fabrication, characterization, and functionalization of dual carbon electrodes as probes for scanning electrochemical microscopy (SECM).

    Science.gov (United States)

    McKelvey, Kim; Nadappuram, Binoy Paulose; Actis, Paolo; Takahashi, Yasufumi; Korchev, Yuri E; Matsue, Tomokazu; Robinson, Colin; Unwin, Patrick R

    2013-08-06

    Dual carbon electrodes (DCEs) are quickly, easily, and cheaply fabricated by depositing pyrolytic carbon into a quartz theta nanopipet. The size of DCEs can be controlled by adjusting the pulling parameters used to make the nanopipet. When operated in generation/collection (G/C) mode, the small separation between the electrodes leads to reasonable collection efficiencies of ca. 30%. A three-dimensional finite element method (FEM) simulation is developed to predict the current response of these electrodes as a means of estimating the probe geometry. Voltammetric measurements at individual electrodes combined with generation/collection measurements provide a reasonable guide to the electrode size. DCEs are employed in a scanning electrochemical microscopy (SECM) configuration, and their use for both approach curves and imaging is considered. G/C approach curve measurements are shown to be particularly sensitive to the nature of the substrate, with insulating surfaces leading to enhanced collection efficiencies, whereas conducting surfaces lead to a decrease of collection efficiency. As a proof-of-concept, DCEs are further used to locally generate an artificial electron acceptor and to follow the flux of this species and its reduced form during photosynthesis at isolated thylakoid membranes. In addition, 2-dimensional images of a single thylakoid membrane are reported and analyzed to demonstrate the high sensitivity of G/C measurements to localized surface processes. It is finally shown that individual nanometer-size electrodes can be functionalized through the selective deposition of platinum on one of the two electrodes in a DCE while leaving the other one unmodified. This provides an indication of the future versatility of this type of probe for nanoscale measurements and imaging.

  20. Wearable Solid-State Supercapacitors Operating at High Working Voltage with a Flexible Nanocomposite Electrode.

    Science.gov (United States)

    Li, Xiaoyan; Wang, Jun; Zhao, Yaping; Ge, Fengyan; Komarneni, Sridhar; Cai, Zaisheng

    2016-10-05

    The proposed approach for fabricating ultralight self-sustained electrodes facilitates the structural integration of highly flexible carbon nanofibers, amino-modified multiwalled carbon nanotubes (AM-MWNT), and MnO 2 nanoflakes for potential use in wearable supercapacitors. Because of the higher orientation of AM-MWNT and the sublimation of terephthalic acid (PTA) in the carbonization process, freestanding electrodes could be realized with high porosity and flexibility and could possess remarkable electrochemical properties without using polymer substrates. Wearable symmetric solid-state supercapacitors were further assembled using a LiCl/PVA gel electrolyte, which exhibit a maximum energy density of 44.57 Wh/kg (at a power density of 337.1 W/kg) and a power density of 13330 W/kg (at an energy density of 19.64 Wh/kg) with a working voltage as high as 1.8 V. Due to the combination of several favorable traits such as flexibility, high energy density, and excellent electrochemical cyclability, the presently developed wearable supercapacitors with wide potential windows are expected to be useful for new kinds of portable electric devices.

  1. Oriented Polyaniline Nanowire Arrays Grown on Dendrimer (PAMAM) Functionalized Multiwalled Carbon Nanotubes as Supercapacitor Electrode Materials.

    Science.gov (United States)

    Jin, Lin; Jiang, Yu; Zhang, Mengjie; Li, Honglong; Xiao, Linghan; Li, Ming; Ao, Yuhui

    2018-04-19

    At present, PANI/MWNT composites have been paid more attention as promising electrode materials in supercapacitors. Yet some shortcomings still limit the widely application of PANI/MWNT electrolytes. In this work, in order to improve capacitance ability and long-term stability of electrode, a multi-amino dendrimer (PAMAM) had been covalently linked onto multi-walled carbon nanotubes (MWNT) as a bridge to facilitating covalent graft of polyaniline (PANI), affording P-MWNT/PANI electrode composites for supercapacitor. Surprisingly, ordered arrays of PANI nanowires on MWNT (setaria-like morphology) had been observed by scanning electron microscopy (SEM). Electrochemical properties of P-MWNT/PANI electrode had been characterized by cyclic voltammetry (CV) and galvanostatic charge-discharge technique. The specific capacitance and long cycle life of P-MWNT-PANI electrode material were both much higher than MWNT/PANI. These interesting results indicate that multi-amino dendrimer, PAMAM, covalently linked on MWNT provides more reaction sites for in-situ polymerization of ordered PANI, which could efficiently shorten the ion diffusion length in electrolytes and lead to making fully use of conducting materials.

  2. Reusable urine glucose sensor based on functionalized graphene oxide conjugated Au electrode with protective layers

    Directory of Open Access Journals (Sweden)

    Hye Youn Kim

    2014-09-01

    Full Text Available An electrochemical based system with multiple layers coated on a functionalized graphene oxide Au electrode was developed to measure glucose concentration in urine in a more stable way. Two types of gold printed circuit boards were fabricated and graphene oxide was immobilized on their surface by chemical adsorption. Multiple layers, composed of a couple of polymers, were uniformly coated on the surface electrode. This device exhibited higher electrochemical responses against glucose, a greater resistivity in the presence of interferential substances in urine, and durable stabilities for longer periods of time than conventional units. The efficiency in current level according to the order and ratio of solution was evaluated during the immobilization of the layer. The fabricated electrodes were then also evaluated using hyperglycemic clinical samples and compared with the patterns of blood glucose measured with commercially available glucose meters. Our findings show that not only was their pattern similar but this similarity is well correlated.

  3. Enzymatic electrodes nanostructured with functionalized carbon nanotubes for biofuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Nazaruk, E.; Bilewicz, R. [University of Warsaw, Faculty of Chemistry, Warsaw (Poland); Sadowska, K.; Biernat, J.F. [Gdansk University of Technology, Chemical Faculty, Gdansk (Poland); Rogalski, J. [Maria Curie Sklodowska University, Department of Biochemistry, Lublin (Poland); Ginalska, G. [Medical University of Lublin, Department of Biochemistry, Lublin (Poland)

    2010-10-15

    Nanostructured bioelectrodes were designed and assembled into a biofuel cell with no separating membrane. The glassy carbon electrodes were modified with mediator-functionalized carbon nanotubes. Ferrocene (Fc) and 2,2{sup '}-azino-bis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) bound chemically to the carbon nanotubes were found useful as mediators of the enzyme catalyzed electrode processes. Glucose oxidase from Aspergillus niger AM-11 and laccase from Cerrena unicolor C-139 were incorporated in a liquid-crystalline matrix-monoolein cubic phase. The carbon nanotubes-nanostructured electrode surface was covered with the cubic phase film containing the enzyme and acted as the catalytic surface for the oxidation of glucose and reduction of oxygen. Thanks to the mediating role of derivatized nanotubes the catalysis was almost ten times more efficient than on the GCE electrodes: catalytic current of glucose oxidation was 1 mA cm{sup -2} and oxygen reduction current exceeded 0.6 mA cm{sup -2}. The open circuit voltage of the biofuel cell was 0.43 V. Application of carbon nanotubes increased the maximum power output of the constructed biofuel cell to 100 {mu}W cm{sup -2} without stirring of the solution which was ca. 100 times more efficient than using the same bioelectrodes without nanotubes on the electrode surface. (orig.)

  4. Impedances of electrochemically impregnated nickel electrodes as functions of potential, KOH concentration, and impregnation method

    Science.gov (United States)

    Reid, Margaret A.

    1989-01-01

    Impedances of fifteen electrodes form each of the four U.S. manufactures were measured at 0.200 V vs. the Hg/HgO reference electrode. This corresponds to a voltage of 1.145 for a Ni/H2 cell. Measurements were also made of a representative sample of these at 0.44 V. At the higher voltage, the impedances were small and very similar, but at the lower voltage there were major differences between manufacturers. Electrodes from the same manufacturers showed only small differences. The impedances of electrodes from two manufacturers were considerably different in 26 percent KOH from those in 31 percent KOH. These preliminary results seen to correlate with the limited data from earlier life testing of cells from these manufacturers. The impedances of cells being tested for Space Station Freedom are being followed, and more impendance measurements of electrodes are being performed as functions of manufacturer, voltage, electrolyte concentration, and cycle history in hopes of finding better correlations of impedance with life.

  5. Ab initio work function of elemental metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Rosengaard, N. M.

    1992-01-01

    We have used a recently developed self-consistent Green’s-function technique based on tight-binding linear-muffin-tin-orbital theory to calculate the work function for the close-packed surfaces of 37 elemental metals. The results agree with the limited experimental data obtained from single cryst...

  6. Development of a 3D origami multiplex electrochemical immunodevice using a nanoporous silver-paper electrode and metal ion functionalized nanoporous gold-chitosan.

    Science.gov (United States)

    Li, Weiping; Li, Long; Li, Meng; Yu, Jinghua; Ge, Shenguang; Yan, Mei; Song, Xianrang

    2013-10-25

    A simple and sensitive 3D microfluidic origami multiplex electrochemical immunodevice was developed for the first time using a novel nanoporous silver modified paper working electrode as a sensor platform and different metal ion functionalized nanoporous gold-chitosan as a tracer.

  7. Efficient electrochemical regeneration of nicotinamide cofactors using a cyclopentadienyl-rhodium complex on functionalized indium tin oxide electrodes

    International Nuclear Information System (INIS)

    Kim, Soojin; Lee, Ga Ye; Lee, Jungha; Rajkumar, Eswaran; Baeg, Jin-Ook; Kim, Jinheung

    2013-01-01

    Functionalized ITO electrodes are used to regenerate NADH using [Cp*Rh(bpy)(H 2 O)] 2+ (Cp* = pentamethylcyclopentadienyl, bpy = 2,2′-bipyridine) electrochemically in a buffer solution. Amino- and mercapto-functionalized electrodes featured higher activity and stability for electrocatalytic generation of NADH than a bare ITO electrode. Effect of metal nanoparticles was also studied on modified ITO electrodes and the addition of platinum nanoparticles even resulted in improved activity. The electrochemical regeneration was somewhat affected in the presence of dioxygen, but not significantly. In addition, a conversion of carbon dioxide was carried out utilizing the electrochemically generated NADH and formate dehydrogenase to produce formic acid

  8. Work function modifications of graphite surface via oxygen plasma treatment

    Science.gov (United States)

    Duch, J.; Kubisiak, P.; Adolfsson, K. H.; Hakkarainen, M.; Golda-Cepa, M.; Kotarba, A.

    2017-10-01

    The surface modification of graphite by oxygen plasma was investigated experimentally (X-ray diffraction, nanoparticle tracking analysis, laser desorption ionization mass spectrometry, thermogravimetry, water contact angle) and by molecular modelling (Density Functional Theory). Generation of surface functional groups (mainly sbnd OHsurf) leads to substantial changes in electrodonor properties and wettability gauged by work function and water contact angle, respectively. The invoked modifications were analyzed in terms of Helmholtz model taking into account the theoretically determined surface dipole moment of graphite-OHsurf system (μ = 2.71 D) and experimentally measured work function increase (from 0.75 to 1.02 eV) to determine the sbnd OH surface coverage (from 0.70 to 1.03 × 1014 groups cm-2). Since the plasma treatment was confined to the surface, the high thermal stability of the graphite material was preserved as revealed by the thermogravimetric analysis. The obtained results provide a suitable quantitative background for tuning the key operating parameters of carbon electrodes: electronic properties, interaction with water and thermal stability.

  9. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    International Nuclear Information System (INIS)

    Verma, Pallavi; Maire, Pascal; Novak, Petr

    2011-01-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH 2 ) 3 OCO 2 Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C 6 H 4 NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C 6 H 4 CH 2 OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  10. Concatenation of electrochemical grafting with chemical or electrochemical modification for preparing electrodes with specific surface functionality

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Pallavi; Maire, Pascal [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland); Novak, Petr, E-mail: petr.novak@psi.c [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland)

    2011-04-01

    Surface modified electrodes are used in electro-analysis, electro-catalysis, sensors, biomedical applications, etc. and could also be used in batteries. The properties of modified electrodes are determined by the surface functionality. Therefore, the steps involved in the surface modification of the electrodes to obtain specific functionality are of prime importance. We illustrate here bridging of two routes of surface modifications namely electrochemical grafting, and chemical or electrochemical reduction. First, by electrochemical grafting an organic moiety is covalently immobilized on the surface. Then, either by chemical or by electrochemical route the terminal functional group of the grafted moiety is transformed. Using the former route we prepared lithium alkyl carbonate (-O(CH{sub 2}){sub 3}OCO{sub 2}Li) modified carbon with potential applications in batteries, and employing the latter we prepared phenyl hydroxyl amine (-C{sub 6}H{sub 4}NHOH) modified carbon which may find application in biosensors. Benzyl alcohol (-C{sub 6}H{sub 4}CH{sub 2}OH) modified carbon was prepared by both chemical as well as electrochemical route. We report combinations of conjugating the two steps of surface modifications and show how the optimal route of terminal functional group modification depends on the chemical nature of the moiety attached to the surface in the electrochemical grafting step.

  11. Capacitance, charge dynamics, and electrolyte-surface interactions in functionalized carbide-derived carbon electrodes

    Directory of Open Access Journals (Sweden)

    Boris Dyatkin

    2015-12-01

    Full Text Available This study analyzed the dynamics of ionic liquid electrolyte inside of defunctionalized, hydrogenated, and aminated pores of carbide-derived carbon supercapacitor electrodes. The approach tailors surface functionalities and tunes nanoporous structures to decouple the influence of pore wall composition on capacitance, ionic resistance, and long-term cyclability. Quasi-elastic neutron scattering probes the self-diffusion properties and electrode-ion interactions of electrolyte molecules confined in functionalized pores. Room-temperature ionic liquid interactions in confined pores are strongest when the hydrogen-containing groups are present on the surface. This property translates into higher capacitance and greater ion transport through pores during electrochemical cycling. Unlike hydrogenated pores, aminated pores do not favorably interact with ionic liquid ions and, subsequently, are outperformed by defunctionalized surfaces.

  12. Capacitance, charge dynamics, and electrolyte-surface interactions in functionalized carbide-derived carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Dyatkin, Boris; Mamontov, Eugene; Cook, Kevin M.; Gogotsi, Yury

    2015-12-01

    This study analyzed the dynamics of ionic liquid electrolyte inside of defunctionalized, hydrogenated, and aminated pores of carbide-derived carbon supercapacitor electrodes. The approach tailors surface functionalities and tunes nanoporous structures to decouple the influence of pore wall composition on capacitance, ionic resistance, and long-term cyclability. Quasi-elastic neutron scattering probes the self-diffusion properties and electrode-ion interactions of electrolyte molecules confined in functionalized pores. Room-temperature ionic liquid interactions in confined pores are strongest when the hydrogen-containing groups are present on the surface. This property translates into higher capacitance and greater ion transport through pores during electrochemical cycling. Unlike hydrogenated pores, aminated pores do not favorably interact with ionic liquid ions and, subsequently, are outperformed by defunctionalized surfaces.

  13. Work function of oxygen exposed lead and lead/indium alloy films

    International Nuclear Information System (INIS)

    Gundlach, K.H.; Hellemann, H.P.; Hoelzl, J.

    1982-01-01

    The effect of indium in superconducting tunnel junctions with lead/indium alloy base electrodes is investigated by measuring the vacuum work function of lead, indium, and lead/indium alloy films. It is found that the anomalous decrease of the work function of lead upon exposure to oxygen, explained by the penetration of oxygen into the inner surface of the lead film, is reversed into a slight increase in work function when some indium is added to the lead. This result indicates that the addition of indium provides a protection by suppressing the penetration of oxygen (and probably other gases) into the interior of the thin film

  14. Variability in EIT Images of Lung Ventilation as a Function of Electrode Planes and Body Positions.

    Science.gov (United States)

    Zhang, Jie; Patterson, Robert

    2014-01-01

    This study is aimed at investigating the variability in resistivity changes in the lung region as a function of air volume, electrode plane and body position. Six normal subjects (33.8 ± 4.7 years, range from 26 to 37 years) were studied using the Sheffield Electrical Impedance Tomography (EIT) portable system. Three transverse planes at the level of second intercostal space, the level of the xiphisternal joint, and midway between upper and lower locations were chosen for measurements. For each plane, sixteen electrodes were uniformly positioned around the thorax. Data were collected with the breath held at end expiration and after inspiring 0.5, 1.0, or 1.5 liters of air from end expiration, with the subject in both the supine and sitting position. The average resistivity change in five regions, two 8x8 pixel local regions in the right lung, entire right, entire left and total lung regions, were calculated. The results show the resistivity change averaged over electrode positions and subject positions was 7-9% per liter of air, with a slightly larger resistivity change of 10 % per liter air in the lower electrode plane. There was no significant difference (p>0.05) between supine and sitting. The two 8x8 regions show a larger inter individual variability (coefficient of variation, CV, is from 30% to 382%) compared to the entire left, entire right and total lung (CV is from 11% to 51%). The results for the global regions are more consistent. The large inter individual variability appears to be a problem for clinical applications of EIT, such as regional ventilation. The variability may be mitigated by choosing appropriate electrode plane, body position and region of interest for the analysis.

  15. Synthesis of hemin functionalized graphene and its application as a counter electrode in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Xu Chunhui; Li Jing; Wang Xianbao; Wang Jingchao; Wan Li; Li Yuanyao; Zhang Min; Shang Xiaopeng; Yang Yingkui

    2012-01-01

    Highlights: ► Hemin functionalized reduced graphene oxide (hemin–RGO) materials were synthesized by microwave irradiation. ► Hemin–RGO exhibits a homogeneous dispersion in water, dimethylformamide, and acetone. ► Hemin–RGO was used as a counter electrode in dye-sensitized solar cells and exhibited preferable electrocatalytic activity. - Abstract: This work reports a facile and rapid method assisted by microwave irradiation for the synthesis of hemin functionalized reduced graphene oxide (hemin–RGO) materials. Our investigation confirmed that the hemin molecules were covalently grafted to the surface of graphene by the amidation reaction of the -NH 2 groups on the edges of ethylenediamine functionalized graphene oxide with the -COOH groups of hemin. Hemin–RGO exhibits a homogeneous dispersion in water, dimethylformamide, and acetone after more than one month, indicating that hemin can effectively improve the dispersion and solubility of RGO in the solvent. Hemin–RGO was used as a counter electrode in dye-sensitized solar cells and exhibited preferable electrocatalytic activity for I 3 − to I − reduction compared with RGO.

  16. Synthesis of hemin functionalized graphene and its application as a counter electrode in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu Chunhui; Li Jing [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Wang Xianbao, E-mail: wangxb68@yahoo.com.cn [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062 (China); Wang Jingchao; Wan Li; Li Yuanyao; Zhang Min; Shang Xiaopeng; Yang Yingkui [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Hemin functionalized reduced graphene oxide (hemin-RGO) materials were synthesized by microwave irradiation. Black-Right-Pointing-Pointer Hemin-RGO exhibits a homogeneous dispersion in water, dimethylformamide, and acetone. Black-Right-Pointing-Pointer Hemin-RGO was used as a counter electrode in dye-sensitized solar cells and exhibited preferable electrocatalytic activity. - Abstract: This work reports a facile and rapid method assisted by microwave irradiation for the synthesis of hemin functionalized reduced graphene oxide (hemin-RGO) materials. Our investigation confirmed that the hemin molecules were covalently grafted to the surface of graphene by the amidation reaction of the -NH{sub 2} groups on the edges of ethylenediamine functionalized graphene oxide with the -COOH groups of hemin. Hemin-RGO exhibits a homogeneous dispersion in water, dimethylformamide, and acetone after more than one month, indicating that hemin can effectively improve the dispersion and solubility of RGO in the solvent. Hemin-RGO was used as a counter electrode in dye-sensitized solar cells and exhibited preferable electrocatalytic activity for I{sub 3}{sup -} to I{sup -} reduction compared with RGO.

  17. Electron work function of stepped tungsten surfaces

    International Nuclear Information System (INIS)

    Krahl-Urban, B.

    1976-03-01

    The electron work function of tungsten (110) vicinal faces was measured with the aid of thermionic emission, and its dependence on the crystallographic orientation and the surface structure was investigated. The thermionic measurements were evaluated with the aid of the Richardson plot. The real temperature of the emitting tungsten faces was determined with an accuracy of +- 0.5% in the range between 2,200 and 2,800 K. The vicinal faces under investigation have been prepared with an orientation exactness of +- 15'. In the tungsten (110) vicinal faces under investigation, a strong dependence of the temperature coefficient d PHI/dT of the work function on the crystallographic orientation was found. A strong influence of the edge structure as well as of the step density on the temperature coefficient was observed. (orig./HPOE) [de

  18. A general phenomenological model for work function

    Science.gov (United States)

    Brodie, I.; Chou, S. H.; Yuan, H.

    2014-07-01

    A general phenomenological model is presented for obtaining the zero Kelvin work function of any crystal facet of metals and semiconductors, both clean and covered with a monolayer of electropositive atoms. It utilizes the known physical structure of the crystal and the Fermi energy of the two-dimensional electron gas assumed to form on the surface. A key parameter is the number of electrons donated to the surface electron gas per surface lattice site or adsorbed atom, which is taken to be an integer. Initially this is found by trial and later justified by examining the state of the valence electrons of the relevant atoms. In the case of adsorbed monolayers of electropositive atoms a satisfactory justification could not always be found, particularly for cesium, but a trial value always predicted work functions close to the experimental values. The model can also predict the variation of work function with temperature for clean crystal facets. The model is applied to various crystal faces of tungsten, aluminium, silver, and select metal oxides, and most demonstrate good fits compared to available experimental values.

  19. Amperometric determination of 6-mercaptopurine on functionalized multi-wall carbon nanotubes modified electrode by liquid chromatography coupled with microdialysis and its application to pharmacokinetics in rabbit.

    Science.gov (United States)

    Cao, Xu-Ni; Lin, Li; Zhou, Yu-Yan; Shi, Guo-Yue; Zhang, Wen; Yamamoto, Katsunobu; Jin, Li-Tong

    2003-07-27

    In this paper, multi-wall carbon nanotubes functionalized with carboxylic groups modified electrode (MWNT-COOH CME) was fabricated. This chemically modified electrode (CME) can be used as the working electrode in the liquid chromatography for the determination of 6-mercaptopurine (6-MP). The results indicate that the CME exhibits efficiently electrocatalytic oxidation for 6-MP with relatively high sensitivity, stability and long-life. The peak currents of 6-MP are linear to its concentrations ranging from 4.0 x 10(-7) to 1.0 x 10(-4) mol l(-1) with the calculated detection limit (S/N=3) of 2.0 x 10(-7) mol l(-1). Coupled with microdialysis, the method has been successfully applied to the pharmacokinetic study of 6-MP in rabbit blood. This method provides a fast, sensible and simple technique for the pharmacokinetic study of 6-MP in vivo.

  20. Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

    International Nuclear Information System (INIS)

    Lee, So Hee; Lim, Sooman; Kim, Haekyoung

    2015-01-01

    Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □ −1 and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □ −1 after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐ −1 ) and high transmittance (87.6%)

  1. Smooth-surface silver nanowire electrode with high conductivity and transparency on functional layer coated flexible film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Hee; Lim, Sooman; Kim, Haekyoung, E-mail: hkkim@ynu.ac.kr

    2015-08-31

    Transparent conductive electrode (TCE) with silver nanowires has been widely studied as an alternative of indium tin oxide for flexible electronic or optical devices such as organic light-emitting diodes, and solar cells. However, it has an issue of surface roughness due to nanowire's intrinsic properties. Here, to achieve a smooth electrode with high conductivity and transmittance on polyethylene terephthalate (PET) substrates, a functional layer of poly(N-vinylpyrrolidone) (PVP) is utilized with a mechanical transfer process. The silver nanowire electrode on PVP-coated PET with low surface roughness of 9 nm exhibits the low sheet resistance of 18 Ω □{sup −1} and high transmittance of 87.6%. It is produced by transferring the silver nanowire electrode spin-coated on the glass to PVP-coated PET using a pressure of 10 MPa for 10 min. Silver nanowire electrode on PVP-coated PET demonstrates the stable sheet resistance of 18 Ω □{sup −1} after the mechanical taping test due to strong adhesion between PVP functional layer and silver nanowires. Smooth TCE with silver nanowires could be proposed as a transparent electrode for flexible electronic or optical devices, which consist of thin electrical active layers on TCE. - Highlights: • Silver nanowire (Ag NWs) transparent electrodes were fabricated on flexible film. • Flexible film was coated with poly N-vinylpyrrolidone (PVP). • PVP layer plays roles as an adhesive layer and matrix in electrode. • Ag NWs electrode exhibited with low surface roughness of 9 nm. • Ag NWs electrode has a low resistance (18 Ω ☐{sup −1}) and high transmittance (87.6%)

  2. The different electron transport of two nanotubes incorporated in working electrode of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaobo, E-mail: zhangxiaobo@chnu.edu.cn [School of Physics, Huaibei Normal University, Huaibei 235000, Anhui (China); Eco-Materials and Renewable Energy Research Centre (ERERC), Nanjing University, Nanjing 210093 (China); Tian, Hanmin; Wang, Xiangyan; Xue, Guogang; Tian, Zhipeng; Zhang, Jiyuan; Yuan, Shikui [Eco-Materials and Renewable Energy Research Centre (ERERC), Nanjing University, Nanjing 210093 (China); Yu, Tao; Zou, Zhigang [Eco-Materials and Renewable Energy Research Centre (ERERC), Nanjing University, Nanjing 210093 (China); National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China)

    2013-11-25

    Highlights: •Two TiO{sub 2} nanotubes are separately incorporated in working electrode of DSSCs. •The 6-μm-tubes incorporation improves electron transport in the cell. •The 1-μm-tubes incorporation impedes electron transport in the cell. •Both 1-D electron diffusion and nanotube percolation promote electron transport. •Electron residing at the end of 1-μm-tubes maybe impedes electron transport. -- Abstract: Two different-length (6 μm and 1 μm) TiO{sub 2} nanotubes were prepared and incorporated in working electrode of dye-sensitized solar cells (DSSCs). The analyses of the electrochemical impedance spectra of cells demonstrate that, the electron transport resistance R{sub w} decreases and increases separately to 0.3 Ω in 6-μm-tubes-cell and to 15.1 Ω in 1-μm-tubes-cell comparing with that 1.4 Ω in P25-cell, reflecting the improved electron transport in 6-μm-tubes-cell and impeded electron transport in 1-μm-tubes-cell. The reason is ascribed to the different electron transport in working electrode due to the incorporation of nanotubes. For the 6-μm-tubes incorporation, both 1-D electron diffusion along nanotubes and nanotube percolation improve electron transport in working electrode, but they cannot improve electron transport for the 1-μm-tubes incorporation. On the contrary, the 1-μm-tubes incorporation may impede electron transport because of electron residing occurring seriously at the end of 1-μm-tubes. The results of this work will help to understand the specific nature of electron transport in TiO{sub 2} nanotubes in DSSCs.

  3. Work function measurements of copper nanoparticle intercalated polyaniline nanocomposite thin films

    Science.gov (United States)

    Patil, U. V.; Ramgir, Niranjan S.; Bhogale, A.; Debnath, A. K.; Muthe, K. P.; Gadkari, S. C.; Kothari, D. C.

    2017-05-01

    The nature of contact between the electrode and the sensing material plays a crucial role in governing the sensing mechanism. Thin films of polyaniline (PANI) and copper-polyaniline nanocomposite (NC) have been deposited at room temperatures by in-situ oxidative polymerization of aniline in the presence of Cu nanoparticles. For sensing applications a thin film Au (gold) ˜100 nm is deposited and used as a conducting electrode. To understand the nature of contact (i.e., ohmic or Schottky) the work function of the conducting polyaniline and nanocomposite films were measured using Kelvin Probe method. I-V characteristics of PANI and NC films investigated at room temperatures further corroborates and confirms the formation of Ohmic contact as evident from work function measurements.

  4. The effect of surface depletion on the work function of arc-melted dilute solution tungsten-iridium alloys

    International Nuclear Information System (INIS)

    D'Cruz, L.A.; Bosch, D.R.; Jacobson, D.L.

    1991-01-01

    The requirements of thermionic electrode materials have emphasized the need for substantial improvements in microstructural stability, strength, and creep resistance at service temperature in excess of 2,500K. The present work extends an earlier study of the effective work function trends of a series of dilute solution tungsten, iridium alloys with iridium contents of 1, 3, and 5 wt%. Since the lifetime of candidate electrode materials is an important consideration, the present work attempts to evaluate the repeatability of the work function trends in these alloys. The effective work function was obtained from measurements of the current emitted from the electrode surface under UHV conditions in the temperature range of 1,800-2,500K using a Vacuum Emission Vehicle (VEV). The data generated in this work have been compared with data obtained in earlier studies performed on these alloys. It was found that the magnitude of the effective work function of these alloys was affected by changes in the subsurface iridium concentration. Furthermore, these alloys exhibited a dependence of the work function on temperature, after prolonged exposure to elevated temperatures. Such a temperature dependence can be explained by diffusion-controlled changes in the coverage of an iridium monolayer on the surface. It is proposed that the significant difference in effective work function trends obtained after prolonged exposure to elevated temperatures is a direct consequence of changes in the coverage of an iridium-rich monolayer on the electrode surface. The constitution of such a surface layer, however, would be governed by composition changes in the subsurface regions of the electrode caused thermally-activated transport processes

  5. Maleimide-activated aryl diazonium salts for electrode surface functionalization with biological and redox-active molecules.

    Science.gov (United States)

    Harper, Jason C; Polsky, Ronen; Wheeler, David R; Brozik, Susan M

    2008-03-04

    A versatile and simple method is introduced for formation of maleimide-functionalized surfaces using maleimide-activated aryl diazonium salts. We show for the first time electrodeposition of N-(4-diazophenyl)maleimide tetrafluoroborate on gold and carbon electrodes which was characterized via voltammetry, grazing angle FTIR, and ellipsometry. Electrodeposition conditions were used to control film thickness and yielded submonolayer-to-multilayer grafting. The resulting phenylmaleimide surfaces served as effective coupling agents for electrode functionalization with ferrocene and the redox-active protein cytochrome c. The utility of phenylmaleimide diazonium toward formation of a diazonium-activated conjugate, followed by direct electrodeposition of the diazonium-modified DNA onto the electrode surface, was also demonstrated. Effective electron transfer was obtained between immobilized molecules and the electrodes. This novel application of N-phenylmaleimide diazonium may facilitate the development of bioelectronic devices including biofuel cells, biosensors, and DNA and protein microarrays.

  6. Effect of the metal work function on the electrical properties of carbon nanotube network transistors

    International Nuclear Information System (INIS)

    Kim, Un Jeong; Ko, Dae Young; Kil, Joon Pyo; Lee, Jung Wha; Park, Wan Jun

    2012-01-01

    A nearly perfect semiconducting single-walled carbon nanotube random network thin film transistor array was fabricated, and its reproducible transport properties were investigated. The effects of the metal work function for both the source and the drain on the electrical properties of the transistors were systematically investigated. Three different metal electrodes, Al, Ti, and Pd, were employed. As the metal work function increased, p-type behavior became dominant, and the field effect hole mobility dramatically increased. Also, the Schottky barrier of the Ti-nanotube contact was invariant to the molecular adsorption of species in air.

  7. Effect of carbon nano tube working electrode thickness on charge transport kinetics and photo-electrochemical characteristics of dye-sensitized solar cells

    Science.gov (United States)

    Gacemi, Yahia; Cheknane, Ali; Hilal, Hikmat S.

    2018-02-01

    Physiochemical processes at the photo-electrode and the counter electrode of dye sensitized solar cells (DSSCs) involving having carbon nanotubes (CNTs) instead of the TiO2 layer, within the working electrode, are simulated in this work. Attention is paid to find the effect of CNT layer thickness on photo-electrochemical (PEC) characteristics of the CNT-DSSCs. Comparison with other conventional TiO2-DSSC systems, taking into account the working electrode film thickness, is also described here. To achieve these goals, a model is presented to explain charge transport and electron recombination which involve electron photo-excitation in dye molecules, injection of electrons from the excited dye to CNT working electrode conduction band, diffusion of electrons inside the CNT electrode, charge transfer between oxidized dye and (I-) and recombination of electrons. The simulation is based on solving non-linear equations using the Newton-Raphson numerical method. This concept is proposed for modelling numerical Faradaic impedance at the photo-electrode and the platinum counter electrode. It then simulates the cell impedance spectrum describing the locus of the three semicircles in the Nyquist diagram. The transient equivalent circuit model is also presented based on optimizing current-voltage curves of CNT-DSSCs so as to optimize the fill factor (FF) and conversion efficiency (η). The results show that the simulated characteristics of CNT-DSSCs, with different active CNT layer thicknesses, are superior to conventional TiO2-DSSCs.

  8. Plasma functionalization of powdery nanomaterials using porous filter electrode and sample circulation

    Science.gov (United States)

    Lee, Deuk Yeon; Choi, Jae Hong; Shin, Jung Chul; Jung, Man Ki; Song, Seok Kyun; Suh, Jung Ki; Lee, Chang Young

    2018-06-01

    Compared with wet processes, dry functionalization using plasma is fast, scalable, solvent-free, and thus presents a promising approach for grafting functional groups to powdery nanomaterials. Previous approaches, however, had difficulties in maintaining an intimate sample-plasma contact and achieving uniform functionalization. Here, we demonstrate a plasma reactor equipped with a porous filter electrode that increases both homogeneity and degree of functionalization by capturing and circulating powdery carbon nanotubes (CNTs) via vacuum and gas blowing. Spectroscopic measurements verify that treatment with O2/air plasma generates oxygen-containing groups on the surface of CNTs, with the degree of functionalization readily controlled by varying the circulation number. Gas sensors fabricated using the plasma-treated CNTs confirm alteration of molecular adsorption on the surface of CNTs. A sequential treatment with NH3 plasma following the oxidation pre-treatment results in the functionalization with nitrogen species of up to 3.2 wt%. Our approach requiring no organic solvents not only is cost-effective and environmentally friendly, but also serves as a versatile tool that applies to other powdery micro or nanoscale materials for controlled modification of their surfaces.

  9. Density Functional Theory Calculations of the Quantum Capacitance of Graphene Oxide as a Supercapacitor Electrode.

    Science.gov (United States)

    Song, Ce; Wang, Jinyan; Meng, Zhaoliang; Hu, Fangyuan; Jian, Xigao

    2018-03-31

    Graphene oxide has become an attractive electrode-material candidate for supercapacitors thanks to its higher specific capacitance compared to graphene. The quantum capacitance makes relative contributions to the specific capacitance, which is considered as the major limitation of graphene electrodes, while the quantum capacitance of graphene oxide is rarely concerned. This study explores the quantum capacitance of graphene oxide, which bears epoxy and hydroxyl groups on its basal plane, by employing density functional theory (DFT) calculations. The results demonstrate that the total density of states near the Fermi level is significantly enhanced by introducing oxygen-containing groups, which is beneficial for the improvement of the quantum capacitance. Moreover, the quantum capacitances of the graphene oxide with different concentrations of these two oxygen-containing groups are compared, revealing that more epoxy and hydroxyl groups result in a higher quantum capacitance. Notably, the hydroxyl concentration has a considerable effect on the capacitive behavior. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Charge transport in films of Geobacter sulfurreducens on graphite electrodes as a function of film thickness

    KAUST Repository

    Jana, Partha Sarathi; Katuri, Krishna; Kavanagh, Paul; Kumar, Amit Ravi Pradeep; Leech, Dó nal

    2014-01-01

    Harnessing, and understanding the mechanisms of growth and activity of, biofilms of electroactive bacteria (EAB) on solid electrodes is of increasing interest, for application to microbial fuel and electrolysis cells. Microbial electrochemical cell technology can be used to generate electricity, or higher value chemicals, from organic waste. The capability of biofilms of electroactive bacteria to transfer electrons to solid anodes is a key feature of this emerging technology, yet the electron transfer mechanism is not fully characterized as yet. Acetate oxidation current generated from biofilms of an EAB, Geobacter sulfurreducens, on graphite electrodes as a function of time does not correlate with film thickness. Values of film thickness, and the number and local concentration of electrically connected redox sites within Geobacter sulfurreducens biofilms as well as a charge transport diffusion co-efficient for the biofilm can be estimated from non-turnover voltammetry. The thicker biofilms, of 50 ± 9 μm, display higher charge transport diffusion co-efficient than that in thinner films, as increased film porosity of these films improves ion transport, required to maintain electro-neutrality upon electrolysis. This journal is © the Partner Organisations 2014.

  11. A density functional theory study of the carbon-coating effects on lithium iron borate battery electrodes

    DEFF Research Database (Denmark)

    Loftager, Simon; García Lastra, Juan Maria; Vegge, Tejs

    2017-01-01

    a density functional theory (DFT) study of the anchoring configurations of carbon coating on the LiFeBO3 electrode and its implications on the interfacial lithium diffusion. Due to large barriers associated with Li-ion diffusion through a parallel-oriented pristine graphene coating on the FeBO3 and LiFeBO3......Lithium iron borate (LiFeBO3) is a promising cathode material due to its high theoretical specific capacity, inexpensive components and a small volume change during operation. Yet, challenges relating to severe air- and moisture-induced degradation necessitate the application of a protective...... coating on the electrode which also improves the electronic conductivity. However, not much is known about the preferential geometries of the coating as well as how these coating–electrode interfaces influence the lithium diffusion between the coating and the electrode. Here, we therefore present...

  12. Efficacy of transgene expression in porcine skin as a function of electrode choice

    DEFF Research Database (Denmark)

    Gotholf, Anita; Mahmood, Faisad; Dagnæs-Hansen, Frederik

    2011-01-01

    , have mainly been performed in rodents and the body of evidence on electrode choice and optimal pulsing conditions is limited. We therefore tested plate and needle electrodes in vivo in porcine skin, which resembles human skin in structure. The luciferase (pCMV-Luc) gene was injected intradermally...... and subsequently electroporated. Simultaneously, studies with gene electrotransfer to porcine skin using plasmids coding for green fluorescent protein (GFP) and betagalactosidase were performed. Interestingly, we found needle electrodes to be more efficient than plate electrodes (p..., our data support that needle electrodes should be used in human clinical studies of gene electrotransfer to skin for improved expression....

  13. Gold Electrode Functionalized with Tridodecylamine for Impedimetric Detection of Acid Orange 10

    Directory of Open Access Journals (Sweden)

    Saida ZOUGAR

    2014-05-01

    Full Text Available In this work, we focus mainly characterize and develop a new type of impedimetric sensor for the detection of acid orange 10 (AO10: textile dye which is a toxic element in waters polluted by industrial waste. A siloprene based membrane was chosen, the used ionophore is the tridodecylamine (TDA. The results are interesting because the developed sensor gives a linear response range of concentrations 10-13 M - 10-3 M for acid orange 10 in aqueous medium with a good correlation coefficient of 0.9862 and a low detection limit of 10-13 M, indicating the sensitivity of the sensor overlooked the target element. Ion sensitivity of sensor has been tested for acid orange 10 via methyl blue (MB. A layer of tridodecylamine deposited on gold electrode has been characterized by impedance spectroscopy and cyclic voltammetry methods.

  14. S-functionalized MXenes as electrode materials for Li-ion batteries

    KAUST Repository

    Zhu, Jiajie

    2016-09-03

    MXenes are promising electrode materials for Li-ion batteries because of their high Li capacities and cycling rates. We use density functional theory to investigate the structural and energy storage properties of Li decorated Zr2C and Zr2CX2 (X = F, O and S). We find for Zr2C and Zr2CS2 high Li specific capacities and low diffusion barriers. To overcome the critical drawbacks of the OH, F, and O groups introduced during the synthesis we propose substitution by S groups and demonstrate that an exchange reaction is indeed possible. Zr2CS2 shows a similar Li specific capacity as Zr2CO2 but a substantially reduced diffusion barrier. © 2016 Elsevier Ltd

  15. Immobilization of flavin adenine dinucleotide (FAD) onto carbon cloth and its application as working electrode in an electroenzymatic bioreactor.

    Science.gov (United States)

    Jayabalan, R; Sathishkumar, M; Jeong, E S; Mun, S P; Yun, S E

    2012-11-01

    A high porosity carbon cloth with immobilized FAD was employed as working electrode in electrochemical NADH-regeneration procedure. Carbon cloth was oxidized with hot acids to create surface carboxyl group and then coupled by adenine amino group of FAD with carbodiimide in the presence of N-hydroxysulfosuccinimide. The bioelectrocatalytic NADH-regeneration was coupled to the conversion of achiral substrate pyruvate into chiral product l-lactate by l-lactate dehydrogenase (l-LDH) within the same reactor. The conversion was completed at 96h in bioreactor with FAD-modified carbon cloth, resulting in about 6mM of l-lactate from 10mM of pyruvate. While with bare carbon cloth, the yield at 120h was around 5mM. Immobilized FAD on the surface of carbon cloth electrode facilitated it to carry electrons from electrode to electron transfer enzymes; thereby NADH-regeneration was accelerated to drive the enzymatic reaction efficiently. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Classification of functional interactions from multi-electrodes data using conditional modularity analysis

    Science.gov (United States)

    Makhtar, Siti Noormiza; Senik, Mohd Harizal

    2018-02-01

    The availability of massive amount of neuronal signals are attracting widespread interest in functional connectivity analysis. Functional interactions estimated by multivariate partial coherence analysis in the frequency domain represent the connectivity strength in this study. Modularity is a network measure for the detection of community structure in network analysis. The discovery of community structure for the functional neuronal network was implemented on multi-electrode array (MEA) signals recorded from hippocampal regions in isoflurane-anaesthetized Lister-hooded rats. The analysis is expected to show modularity changes before and after local unilateral kainic acid (KA)-induced epileptiform activity. The result is presented using color-coded graphic of conditional modularity measure for 19 MEA nodes. This network is separated into four sub-regions to show the community detection within each sub-region. The results show that classification of neuronal signals into the inter- and intra-modular nodes is feasible using conditional modularity analysis. Estimation of segregation properties using conditional modularity analysis may provide further information about functional connectivity from MEA data.

  17. Electrochemical Characterization of O2 Plasma Functionalized Multi-Walled Carbon Nanotube Electrode for Legionella pneumophila DNA Sensor

    Science.gov (United States)

    Park, Eun Jin; Lee, Jun-Yong; Hyup Kim, Jun; Kug Kim, Sun; Lee, Cheol Jin; Min, Nam Ki

    2010-08-01

    An electrochemical DNA sensor for Legionella pneumophila detection was constructed using O2 plasma functionalized multi-walled carbon nanotube (MWCNT) film as a working electrode (WE). The cyclic voltammetry (CV) results revealed that the electrocatalytic activity of plasma functionalized MWCNT (pf-MWCNT) significantly changed depending on O2 plasma treatment time due to some oxygen containing functional groups on the pf-MWCNT surface. Scanning electron microscope (SEM) images and X-ray photoelectron spectroscopy (XPS) spectra were also presented the changes of their surface morphologies and oxygen composition before and after plasma treatment. From a comparison study, it was found that the pf-MWCNT WEs had higher electrocatalytic activity and more capability of probe DNA immobilization: therefore, electrochemical signal changes by probe DNA immobilization and hybridization on pf-MWCNT WEs were larger than on Au WEs. The pf-MWCNT based DNA sensor was able to detect a concentration range of 10 pM-100 nM of target DNA to detect L. pneumophila.

  18. Functionalization of indium-tin-oxide electrodes by laser-nanostructured gold thin films for biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Grochowska, Katarzyna, E-mail: kgrochowska@imp.gda.pl [Centre for Plasma and Laser Engineering, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland); Siuzdak, Katarzyna [Centre for Plasma and Laser Engineering, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland); Karczewski, Jakub [Solid State Physics Department, Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, 11/12 Narutowicza St, 80-233, Gdańsk (Poland); Śliwiński, Gerard [Centre for Plasma and Laser Engineering, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St, 80-231 Gdańsk (Poland)

    2015-12-01

    Graphical abstract: - Highlights: • ITO electrodes modified by NP arrays prepared by laser dewetting of thin Au films. • Enhanced activity, linear response and high sensitivity towards glucose. • Promising biosensor material AuNP-modified ITO of improved performance. - Abstract: The production and properties of the indium-tin-oxide (ITO) electrodes functionalized by Au nanoparticle (NP) arrays of a relatively large area formed by pulsed laser nanostructuring of thin gold films are reported and discussed. The SEM inspection of modified electrodes reveals the presence of the nearly spherical and disc-shaped particles of dimensions in the range of 40–120 nm. The NP-array geometry can be controlled by selection of the laser processing conditions. It is shown that particle size and packing density of the array are important factors which determine the electrode performance. In the case of NP-modified electrodes the peak current corresponding to the glucose direct oxidation process shows rise with increasing glucose concentration markedly higher comparing to the reference Au disc electrode. The detection limit reaches 12 μM and linear response of the sensor is observed from 0.1 to 47 mM that covers the normal physiological range of the blood sugar detection.

  19. A density functional theory study of the carbon-coating effects on lithium iron borate battery electrodes.

    Science.gov (United States)

    Loftager, Simon; García-Lastra, Juan María; Vegge, Tejs

    2017-01-18

    Lithium iron borate (LiFeBO 3 ) is a promising cathode material due to its high theoretical specific capacity, inexpensive components and small volume change during operation. Yet, challenges related to severe air- and moisture-induced degradation have prompted the utilization of a protective coating on the electrode which also improves the electronic conductivity. However, not much is known about the preferential geometries of the coating as well as how these coating-electrode interfaces influence the lithium diffusion between the coating and the electrode. Here, we therefore present a density functional theory (DFT) study of the anchoring configurations of carbon coating on the LiFeBO 3 electrode and its implications on the interfacial lithium diffusion. Due to large barriers associated with Li-ion diffusion through a parallel-oriented pristine graphene coating on the FeBO 3 and LiFeBO 3 electrode surfaces, large structural defects in the graphene coating are required for fast Li-ion diffusion. However, such defects are expected to exist only in small concentrations due to their high formation energies. Alternative coating geometries were therefore investigated, and the configuration in which the coating layers were anchored normal to the electrode surface at B and O atoms was found to be most stable. Nudged elastic band (NEB) calculations of the lithium diffusion barriers across the interface between the optimally oriented coating layers and the electrode show no kinetic limitations for lithium extraction and insertion. Additionally, this graphite-coating configuration showed partial blocking of electrode-degrading species.

  20. Ab initio joint density-functional theory of solvated electrodes, with model and explicit solvation

    Science.gov (United States)

    Arias, Tomas

    2015-03-01

    First-principles guided design of improved electrochemical systems has the potential for great societal impact by making non-fossil-fuel systems economically viable. Potential applications include improvements in fuel-cells, solar-fuel systems (``artificial photosynthesis''), supercapacitors and batteries. Economical fuel-cell systems would enable zero-carbon footprint transportation, solar-fuel systems would directly convert sunlight and water into hydrogen fuel for such fuel-cell vehicles, supercapacitors would enable nearly full recovery of energy lost during vehicle braking thus extending electric vehicle range and acceptance, and economical high-capacity batteries would be central to mitigating the indeterminacy of renewable resources such as wind and solar. Central to the operation of all of the above electrochemical systems is the electrode-electrolyte interface, whose underlying physics is quite rich, yet remains remarkably poorly understood. The essential underlying technical challenge to the first principles studies which could explore this physics is the need to properly represent simultaneously both the interaction between electron-transfer events at the electrode, which demand a quantum mechanical description, and multiscale phenomena in the liquid environment such as the electrochemical double layer (ECDL) and its associated shielding, which demand a statistical description. A direct ab initio approach to this challenge would, in principle, require statistical sampling and thousands of repetitions of already computationally demanding quantum mechanical calculations. This talk will begin with a brief review of a recent advance, joint density-functional theory (JDFT), which allows for a fully rigorous and, in principle, exact representation of the thermodynamic equilibrium between a system described at the quantum-mechanical level and a liquid environment, but without the need for costly sampling. We then shall demonstrate how this approach applies in

  1. A Multi-Functional Microelectrode Array Featuring 59760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement and Neurotransmitter Detection Channels.

    Science.gov (United States)

    Dragas, Jelena; Viswam, Vijay; Shadmani, Amir; Chen, Yihui; Bounik, Raziyeh; Stettler, Alexander; Radivojevic, Milos; Geissler, Sydney; Obien, Marie; Müller, Jan; Hierlemann, Andreas

    2017-06-01

    Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date (4.48×2.43 mm 2 ) to accommodate 59,760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5 μm electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2,048 action-potential (AP, bandwidth: 300 Hz to 10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz to 300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel.

  2. Efficacy of transgene expression in porcine skin as a function of electrode choice

    DEFF Research Database (Denmark)

    Gothelf, A; Mahmood, Faisal; Dagnaes-Hansen, Frederik

    2011-01-01

    , have mainly been performed in rodents and the body of evidence on electrode choice and optimal pulsing conditions is limited. We therefore tested plate and needle electrodes in vivo in porcine skin, which resembles human skin in structure. The luciferase (pCMV-Luc) gene was injected intradermally...... and subsequently electroporated. Simultaneously, studies with gene electrotransfer to porcine skin using plasmids coding for green fluorescent protein (GFP) and betagalactosidase were performed. Interestingly, we found needle electrodes to be more efficient than plate electrodes (p...

  3. Work functioning trajectories in cancer patients: Results from the longitudinal Work Life after Cancer (WOLICA) study.

    Science.gov (United States)

    Dorland, Heleen F; Abma, Femke I; Roelen, Corné A M; Stewart, Roy E; Amick, Benjamin C; Ranchor, Adelita V; Bültmann, Ute

    2017-11-01

    More than 60% of cancer patients are able to work after cancer diagnosis. However, little is known about their functioning at work. Therefore, the aims of this study were to (1) identify work functioning trajectories in the year following return to work (RTW) in cancer patients and (2) examine baseline sociodemographic, health-related and work-related variables associated with work functioning trajectories. This longitudinal cohort study included 384 cancer patients who have returned to work after cancer diagnosis. Work functioning was measured at baseline, 3, 6, 9 and 12 months follow-up. Latent class growth modeling (LCGM) was used to identify work functioning trajectories. Associations of baseline variables with work functioning trajectories were examined using univariate and multivariate analyses. LCGM analyses with cancer patients who completed on at least three time points the Work Role Functioning Questionnaire (n = 324) identified three work functioning trajectories: "persistently high" (16% of the sample), "moderate to high" (54%) and "persistently low" work functioning (32%). Cancer patients with persistently high work functioning had less time between diagnosis and RTW and had less often a changed meaning of work, while cancer patients with persistently low work functioning reported more baseline cognitive symptoms compared to cancer patients in the other trajectories. This knowledge has implications for cancer care and guidance of cancer patients at work. © 2017 UICC.

  4. New method for characterizing electron mediators in microbial systems using a thin-layer twin-working electrode cell.

    Science.gov (United States)

    Hassan, Md Mahamudul; Cheng, Ka Yu; Ho, Goen; Cord-Ruwisch, Ralf

    2017-01-15

    Microbial biofilms are significant ecosystems where the existence of redox gradients drive electron transfer often via soluble electron mediators. This study describes the use of two interfacing working electrodes (WEs) to simulate redox gradients within close proximity (250µm) for the detection and quantification of electron mediators. By using a common counter and reference electrode, the potentials of the two WEs were independently controlled to maintain a suitable "voltage window", which enabled simultaneous oxidation and reduction of electron mediators as evidenced by the concurrent anodic and cathodic currents, respectively. To validate the method, the electrochemical properties of different mediators (hexacyanoferrate, HCF, riboflavin, RF) were characterized by stepwise shifting the "voltage window" (ranging between 25 and 200mV) within a range of potentials after steady equilibrium current of both WEs was established. The resulting differences in electrical currents between the two WEs were recorded across a defined potential spectrum (between -1V and +0.5V vs. Ag/AgCl). Results indicated that the technique enabled identification (by the distinct peak locations at the potential scale) and quantification (by the peak of current) of the mediators for individual species as well as in an aqueous mixture. It enabled a precise determination of mid-potentials of the externally added mediators (HCF, RF) and mediators produced by pyocyanin-producing Pseudomonas aeruginosa (WACC 91) culture. The twin working electrode described is particularly suitable for studying mediator-dependent microbial electron transfer processes or simulating redox gradients as they exist in microbial biofilms. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Effect of Strong Acid Functional Groups on Electrode Rise Potential in Capacitive Mixing by Double Layer Expansion

    KAUST Repository

    Hatzell, Marta C.; Raju, Muralikrishna; Watson, Valerie J.; Stack, Andrew G.; van Duin, Adri C. T.; Logan, Bruce E.

    2014-01-01

    © 2014 American Chemical Society. The amount of salinity-gradient energy that can be obtained through capacitive mixing based on double layer expansion depends on the extent the electric double layer (EDL) is altered in a low salt concentration (LC) electrolyte (e.g., river water). We show that the electrode-rise potential, which is a measure of the EDL perturbation process, was significantly (P = 10-5) correlated to the concentration of strong acid surface functional groups using five types of activated carbon. Electrodes with the lowest concentration of strong acids (0.05 mmol g-1) had a positive rise potential of 59 ± 4 mV in the LC solution, whereas the carbon with the highest concentration (0.36 mmol g-1) had a negative rise potential (-31 ± 5 mV). Chemical oxidation of a carbon (YP50) using nitric acid decreased the electrode rise potential from 46 ± 2 mV (unaltered) to -6 ± 0.5 mV (oxidized), producing a whole cell potential (53 ± 1.7 mV) that was 4.4 times larger than that obtained with identical electrode materials (from 12 ± 1 mV). Changes in the EDL were linked to the behavior of specific ions in a LC solution using molecular dynamics and metadynamics simulations. The EDL expanded in the LC solution when a carbon surface (pristine graphene) lacked strong acid functional groups, producing a positive-rise potential at the electrode. In contrast, the EDL was compressed for an oxidized surface (graphene oxide), producing a negative-rise electrode potential. These results established the linkage between rise potentials and specific surface functional groups (strong acids) and demonstrated on a molecular scale changes in the EDL using oxidized or pristine carbons.

  6. Effect of Strong Acid Functional Groups on Electrode Rise Potential in Capacitive Mixing by Double Layer Expansion

    KAUST Repository

    Hatzell, Marta C.

    2014-12-02

    © 2014 American Chemical Society. The amount of salinity-gradient energy that can be obtained through capacitive mixing based on double layer expansion depends on the extent the electric double layer (EDL) is altered in a low salt concentration (LC) electrolyte (e.g., river water). We show that the electrode-rise potential, which is a measure of the EDL perturbation process, was significantly (P = 10-5) correlated to the concentration of strong acid surface functional groups using five types of activated carbon. Electrodes with the lowest concentration of strong acids (0.05 mmol g-1) had a positive rise potential of 59 ± 4 mV in the LC solution, whereas the carbon with the highest concentration (0.36 mmol g-1) had a negative rise potential (-31 ± 5 mV). Chemical oxidation of a carbon (YP50) using nitric acid decreased the electrode rise potential from 46 ± 2 mV (unaltered) to -6 ± 0.5 mV (oxidized), producing a whole cell potential (53 ± 1.7 mV) that was 4.4 times larger than that obtained with identical electrode materials (from 12 ± 1 mV). Changes in the EDL were linked to the behavior of specific ions in a LC solution using molecular dynamics and metadynamics simulations. The EDL expanded in the LC solution when a carbon surface (pristine graphene) lacked strong acid functional groups, producing a positive-rise potential at the electrode. In contrast, the EDL was compressed for an oxidized surface (graphene oxide), producing a negative-rise electrode potential. These results established the linkage between rise potentials and specific surface functional groups (strong acids) and demonstrated on a molecular scale changes in the EDL using oxidized or pristine carbons.

  7. An amperometric bienzymatic cholesterol biosensor based on functionalized graphene modified electrode and its electrocatalytic activity towards total cholesterol determination.

    Science.gov (United States)

    Manjunatha, Revanasiddappa; Shivappa Suresh, Gurukar; Melo, Jose Savio; D'Souza, Stanislaus F; Venkatesha, Thimmappa Venkatarangaiah

    2012-09-15

    Cholesterol oxidase (ChOx) and cholesterol esterase (ChEt) have been covalently immobilized onto functionalized graphene (FG) modified graphite electrode. Enzymes modified electrodes were characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). FG accelerates the electron transfer from electrode surface to the immobilized ChOx, achieving the direct electrochemistry of ChOx. A well defined redox peak was observed, corresponding to the direct electron transfer of the FAD/FADH(2) of ChOx. The electron transfer coefficient (α) and electron transfer rate constant (K(s)) were calculated and their values are found to be 0.31 and 0.78 s(-1), respectively. For the free cholesterol determination, ChOx-FG/Gr electrode exhibits a sensitive response from 50 to 350 μM (R=-0.9972) with a detection limit of 5 μM. For total cholesterol determination, co-immobilization of ChEt and ChOx on modified electrode, i.e. (ChEt/ChOx)-FG/Gr electrode showed linear range from 50 to 300 μM (R=-0.9982) with a detection limit of 15 μM. Some common interferents like glucose, ascorbic acid and uric acid did not cause any interference, due to the use of a low operating potential. The FG/Gr electrode exhibits good electrocatalytic activity towards hydrogen peroxide (H(2)O(2)). A wide linear response to H(2)O(2) ranging from 0.5 to 7 mM (R=-0.9967) with a sensitivity of 443.25 μA mM(-1) cm(-2) has been obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Electron emission and work function-Past, present and future

    International Nuclear Information System (INIS)

    Yamamoto, Shigehiko

    2005-01-01

    The history of electron emission is reviewed from a standpoint of the work function and the applications. For years, in the field of thermionic emission, a great deal of efforts have been devoted to search for low work function materials with a high melting temperature, while the reduction of the local change in time of the work function rather than the work function itself has been the main issue of field emission investigations. High brightness and long life are the central targets of the emission material investigations for the scientific instrument application, while high current density and low power consumption are the guiding principles for the display application. In both fields, field emission has recently become dominant in research and development. In all above cases, the main issue in the future research works will be to analyze the work function in atomic level and thereby to understand the mechanism of the work function reduction by atom adsorption, the change in time of the local work function leading to the current fluctuation, and the relationship between microscopic and macroscopic work functions. Our attempt is discussed, where the work function in atomic level is measured by utilizing the STM technique and it is made clear how far the work function in atomic level extends its influence over the neighboring sites. As a result, a simple relationship is established between microscopic and macroscopic work functions

  9. The role of iridium in the work-function behavior of dilute-solution tungsten, iridium alloys

    International Nuclear Information System (INIS)

    D'Cruz, L.A.

    1991-01-01

    Requirements of thermionic electrode materials have emphasized the need for substantial improvements in microstructural stability, strength and creep resistance at service temperatures in excess of 2,500K. This study utilized both chemical alloying and mechanical alloying procedures for the addition of iridium to submicron W powder followed by cold compaction and sintering. The shrinkage characteristics and microstructural development were studied in iridium-added tungsten compacts with a range of additive levels. An electron-emission study was subsequently carried out in order to evaluate the work-function behavior of the consolidated alloys. The work function was obtained from current-emission measurements from the electrode surface under UHV conditions in the temperature range of 1,800 to 2,500K using a Vacuum Emission Vehicle (VEV). The data show that the magnitude of the work function in these alloys varied with temperature and was sensitive to sub-surface iridium content

  10. Ionic liquid-functionalized graphene as modifier for electrochemical and electrocatalytic improvement: comparison of different carbon electrodes.

    Science.gov (United States)

    Du, Meng; Yang, Tao; Ma, Suyan; Zhao, Changzhi; Jiao, Kui

    2011-04-01

    Electrochemical activities of typically electrochemical targets at three kinds of modified carbon electrodes, i.e. carbon ionic liquid electrode (CILE), graphene/carbon paste electrode (CPE), and ionic liquid-functionalized graphene (IL-graphene)/CPE, were compared in detail. The redox processes of the probes at IL-graphene/CPE were faster than those at CILE and graphene/CPE from cyclic voltammetry. An electrochemical method for the simultaneous determination of guanine and adenine was described with detection limits of 6.5×10(-8) mol L(-1) (guanine) and 3.2×10(-8) mol L(-1) (adenine). Single A→G mutation of sequence-specific DNA could be discriminated by the IL-graphene/CPE. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Impaired work functioning due to common mental disorders in nurses and allied health professionals: the Nurses Work Functioning Questionnaire

    NARCIS (Netherlands)

    Gärtner, F. R.; Nieuwenhuijsen, K.; van Dijk, F. J. H.; Sluiter, J. K.

    2012-01-01

    Common mental disorders (CMD) negatively affect work functioning. In the health service sector not only the prevalence of CMDs is high, but work functioning problems are associated with a risk of serious consequences for patients and healthcare providers. If work functioning problems due to CMDs are

  12. Preparation of alanine and tyrosine functionalized graphene oxide nanoflakes and their modified carbon paste electrodes for the determination of dopamine

    International Nuclear Information System (INIS)

    Kumar, Mohan; Swamy, B.E. Kumara; Asif, M.H. Mohammed; Viswanath, C.C.

    2017-01-01

    Highlights: • The prepared graphene oxide was functionalized by alanine and tyrosine. • The prepared materials were used for sensor for dopamine. • The functionalized graphene oxide modified carbon paste electrodes shows good sensitivity, stability and repeatability. - Abstract: Herein, established the synthesis of graphene oxide (GO) by Hummers Method with addition of KMnO_4 followed by thermal heating at 80 °C. The obtained GO was further functionalized by alanine and tyrosine. The prepared GO, alanine functionalized GO nanoflakes (AGONF) and tyrosine functionalized GO nanoflakes (TGONF) were characterized by spectroscopic technique using energy-dispersive spectroscopy (EDS), quantitatively by scanning electron microscopy (SEM) and structural studies along with interlayer distance verified through X-ray diffraction technique. Afterwards, the prepared AGONF and TGONF were used as the modifier for the carbon paste electrode (CPE). The electrochemical behavior of the AGONF and TGONF modified carbon paste electrodes (MCPEs) towards dopamine (DA) in phosphate buffer solution (PBS) were examined by cyclic voltammetric (CV) technique and the obtained consequences showed good electrocatalytic activity of MCPEs by increasing the redox peak current with a lower potential difference compared to the bare CPE (BCPE). The AGONF and TGONF MCPEs were further used for the optimization studies. From the pH studies, it was found that the equal number of proton and electron transfer reaction involved in both the modified electrodes. The scan rate studies demonstrate the adsorption controlled electrode process at AGONF MCPE and diffusion controlled at TGONF MCPE. The oxidation peak current increased linearly with two concentration interval of DA at a range of 2–7 μM and 10–30 μM in presence of PBS (pH 7.4) at MCPEs and the limit of detection (LOD) were found to be 0.84 μM and 0.96 μM for first interval DA concentration range (2–7 μM) at AGONF and TGONF MCPE. The

  13. Preparation of alanine and tyrosine functionalized graphene oxide nanoflakes and their modified carbon paste electrodes for the determination of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mohan [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India); Swamy, B.E. Kumara, E-mail: kumaraswamy21@yahoo.com [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India); Asif, M.H. Mohammed [Nanoscience and Technology, Kuvempu University, Shankaraghatta, 577451, Shimoga, Karnataka (India); Viswanath, C.C. [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India)

    2017-03-31

    Highlights: • The prepared graphene oxide was functionalized by alanine and tyrosine. • The prepared materials were used for sensor for dopamine. • The functionalized graphene oxide modified carbon paste electrodes shows good sensitivity, stability and repeatability. - Abstract: Herein, established the synthesis of graphene oxide (GO) by Hummers Method with addition of KMnO{sub 4} followed by thermal heating at 80 °C. The obtained GO was further functionalized by alanine and tyrosine. The prepared GO, alanine functionalized GO nanoflakes (AGONF) and tyrosine functionalized GO nanoflakes (TGONF) were characterized by spectroscopic technique using energy-dispersive spectroscopy (EDS), quantitatively by scanning electron microscopy (SEM) and structural studies along with interlayer distance verified through X-ray diffraction technique. Afterwards, the prepared AGONF and TGONF were used as the modifier for the carbon paste electrode (CPE). The electrochemical behavior of the AGONF and TGONF modified carbon paste electrodes (MCPEs) towards dopamine (DA) in phosphate buffer solution (PBS) were examined by cyclic voltammetric (CV) technique and the obtained consequences showed good electrocatalytic activity of MCPEs by increasing the redox peak current with a lower potential difference compared to the bare CPE (BCPE). The AGONF and TGONF MCPEs were further used for the optimization studies. From the pH studies, it was found that the equal number of proton and electron transfer reaction involved in both the modified electrodes. The scan rate studies demonstrate the adsorption controlled electrode process at AGONF MCPE and diffusion controlled at TGONF MCPE. The oxidation peak current increased linearly with two concentration interval of DA at a range of 2–7 μM and 10–30 μM in presence of PBS (pH 7.4) at MCPEs and the limit of detection (LOD) were found to be 0.84 μM and 0.96 μM for first interval DA concentration range (2–7 μM) at AGONF and TGONF MCPE

  14. Barium Staminate as Semiconductor Working Electrodes for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Fu-an Guo

    2010-01-01

    Full Text Available Dye-sensitized solar cells (DSSCs are fabricated with perovskite-type BaSnO3 as the photoelectrode materials. Different preparation methods including coprecipitation, hydrothermal, and solid state reaction are employed to synthesize BaSnO3 particles to optimize the photoelectric activities of electrode materials. The photoelectric properties of BaSnO3 particles and the performances of DSSCs are investigated by surface photovoltage spectroscopy and current-voltage measurements. The light-to-electricity conversion of 1.1% is preliminarily reached on the DSSC made of the coprecipitation-derived BaSnO3 particles. Large current density of hole injection into the HOMO level of N719 dye from the valence band of BaSnO3 and reduced photogenerated charge recombination in BaSnO3 could be responsible for the observed solar cell performance of the DSSC fabricated from the coprecipitation-derived BaSnO3 particles.

  15. A new potentiometric electrode incorporating functionalized β-cyclodextrins for diclofenac determination.

    Science.gov (United States)

    Lenik, Joanna

    2014-12-01

    This paper reports the preparation of diclofenac-selective membrane electrodes incorporating β-cyclodextrins: (2-hydroxypropyl)-β-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, and heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin. Several plasticized poly(vinyl chloride) membranes of different compositions were tested with the best electrode being the one incorporating heptakis(2,3,6-tri-O-benzoyl)-β-cyclodextrin with the membrane plasticized with 2-nitrophenyloctyl ether. The electrode is characterized by a near-Nernstian response slope of -60.0 mV decade(-1) over the linear range of 5.0×10(-5)-1.0×10(-2) mol L(-1) and a limit of detection of 1.4×10(-5) mol L(-1). The proposed electrode can easily discriminate diclofenac ions from several inorganic and organic interferents and some common drug excipients. The electrode has a response time of 10s and can be used within a pH range of 6.2-8.5 over 10 months without any considerable deterioration. The electrical properties of the membrane electrode were studied by impedance spectroscopy. The notable advantages of the diclofenac-selective electrode include its high sensitivity, selectivity, cost-effectiveness, and comfortable application in drug and urine analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Reduction of the Work Function of Gold by N-Heterocyclic Carbenes

    KAUST Repository

    Kim, Hye Kyung

    2017-04-12

    N-Heterocyclic carbenes (NHCs) bind strongly to gold and other metals. This work experimentally probes the effect of NHCs on the work function (WF) of gold for the first time, theoretically analyzes the origin of this effect, and examines the effectiveness of NHC-modified gold as an electron-injecting electrode. UV photoelectron spectroscopy shows the WF of planar gold is reduced by nearly 2 eV to values of 3.3–3.5 eV. This effect is seen for NHCs with various heterocyclic cores, and with either small or large N,N′-substituents. DFT calculations indicate the WF reduction results from both the interface dipole formed between the NHC and the gold and from the NHC molecular dipole. For N,N′-diisopropyl-NHCs, an important contributor to the former is charge transfer associated with coordination of the carbene carbon atom to gold. In contrast, the carbene carbon of N,N′-2,6-diisopropylphenyl-NHCs is not covalently bound to gold, resulting in a lower interface dipole; however, a larger molecular dipole partially compensates for this. Single-layer C60 diodes with NHC-modified gold as the bottom electrode demonstrate high rectification ratios and show that these electrodes can act as effective electron-injecting contacts, suggesting they may be useful for a variety of materials applications.

  17. Reduction of the Work Function of Gold by N-Heterocyclic Carbenes

    KAUST Repository

    Kim, Hye Kyung; Hyla, Alexander; Winget, Paul; Li, Hong; Wyss, Chelsea M.; Jordan, Abraham J.; Larrain, Felipe A.; Sadighi, Joseph P.; Fuentes-Hernandez, Canek; Kippelen, Bernard; Bredas, Jean-Luc; Barlow, Stephen; Marder, Seth R.

    2017-01-01

    N-Heterocyclic carbenes (NHCs) bind strongly to gold and other metals. This work experimentally probes the effect of NHCs on the work function (WF) of gold for the first time, theoretically analyzes the origin of this effect, and examines the effectiveness of NHC-modified gold as an electron-injecting electrode. UV photoelectron spectroscopy shows the WF of planar gold is reduced by nearly 2 eV to values of 3.3–3.5 eV. This effect is seen for NHCs with various heterocyclic cores, and with either small or large N,N′-substituents. DFT calculations indicate the WF reduction results from both the interface dipole formed between the NHC and the gold and from the NHC molecular dipole. For N,N′-diisopropyl-NHCs, an important contributor to the former is charge transfer associated with coordination of the carbene carbon atom to gold. In contrast, the carbene carbon of N,N′-2,6-diisopropylphenyl-NHCs is not covalently bound to gold, resulting in a lower interface dipole; however, a larger molecular dipole partially compensates for this. Single-layer C60 diodes with NHC-modified gold as the bottom electrode demonstrate high rectification ratios and show that these electrodes can act as effective electron-injecting contacts, suggesting they may be useful for a variety of materials applications.

  18. Influence of Surface Adsorption on Work Function Measurements on Gold-Platinum Interface Using Scanning Kelvin Probe Microscopy

    International Nuclear Information System (INIS)

    Mugo, Simon; Yuan Jun

    2012-01-01

    Surface potential difference (SPD) on freshly coated gold and platinum electrodes have been found to be much smaller than bulk work functions consideration and to be dependent on time. We show these discrepancies arise due to formation of surface dipoles caused by adsorbed contaminants in ambient environments. The process is reversible by gentle annealing consistent with contaminant hypothesis. Examination of potential changes on individual electrodes suggest that the Pt surface is more sensitive to ambient conditions than the Au surface in accordance with their relative chemical activities. The result has great implication for interpretation of Kelvin probe measurements obtained on practical devices exposed to ambient environments.

  19. Electrochemical Sensor for Bilirubin Detection Using Screen Printed Electrodes Functionalized with Carbon Nanotubes and Graphene.

    Science.gov (United States)

    Thangamuthu, Madasamy; Gabriel, Willimann Eric; Santschi, Christian; Martin, Olivier J F

    2018-03-07

    Practice oriented point-of-care diagnostics require easy-to-handle, miniaturized, and low-cost analytical tools. In a novel approach, screen printed carbon electrodes (SPEs), which were functionalized with nanomaterials, are employed for selective measurements of bilirubin, which is an important biomarker for jaundice. Multi-walled carbon nanotubes (MWCNT) and graphene separately deposited on SPEs provide the core of an electrochemical sensor for bilirubin. The electrocatalytic activity towards bilirubin oxidation (bilirubin to biliverdin) was observed at +0.25 V. In addition, a further peak corresponding to the electrochemical conversion of biliverdin into purpurin appeared at +0.48 V. When compared to MWCNT, the graphene type shows a 3-fold lower detection limit (0.3 ± 0.022 nM and 0.1 ± 0.018 nM, respectively), moreover, the graphene type exhibits a larger linear range (0.1-600 µM) than MWCNT (0.5-500 µM) with a two-fold better sensitivity, i.e., 30 nA µM -1 cm -2 , and 15 nA µM -1 cm -2 , respectively. The viability is validated through measurements of bilirubin in blood serum samples and the selectivity is ensured by inhibiting common interfering biological substrates using an ionic nafion membrane. The presented approach enables the design and implementation of low cost and miniaturized electrochemical sensors.

  20. Electrochemical Sensor for Bilirubin Detection Using Screen Printed Electrodes Functionalized with Carbon Nanotubes and Graphene

    Directory of Open Access Journals (Sweden)

    Madasamy Thangamuthu

    2018-03-01

    Full Text Available Practice oriented point-of-care diagnostics require easy-to-handle, miniaturized, and low-cost analytical tools. In a novel approach, screen printed carbon electrodes (SPEs, which were functionalized with nanomaterials, are employed for selective measurements of bilirubin, which is an important biomarker for jaundice. Multi-walled carbon nanotubes (MWCNT and graphene separately deposited on SPEs provide the core of an electrochemical sensor for bilirubin. The electrocatalytic activity towards bilirubin oxidation (bilirubin to biliverdin was observed at +0.25 V. In addition, a further peak corresponding to the electrochemical conversion of biliverdin into purpurin appeared at +0.48 V. When compared to MWCNT, the graphene type shows a 3-fold lower detection limit (0.3 ± 0.022 nM and 0.1 ± 0.018 nM, respectively, moreover, the graphene type exhibits a larger linear range (0.1–600 µM than MWCNT (0.5–500 µM with a two-fold better sensitivity, i.e., 30 nA µM−1 cm−2, and 15 nA µM−1 cm−2, respectively. The viability is validated through measurements of bilirubin in blood serum samples and the selectivity is ensured by inhibiting common interfering biological substrates using an ionic nafion membrane. The presented approach enables the design and implementation of low cost and miniaturized electrochemical sensors.

  1. Facilely prepared, N, O-codoped nanosheet derived from pre-functionalized polymer as supercapacitor electrodes

    Science.gov (United States)

    Wang, Jun; Yang, Ting; Zeng, Zheling; Deng, Shuguang

    2018-04-01

    Nitrogen and oxygen codoped carbon nanosheets derived from pre-functionalized polymer were prepared using a facile direct pyrolysis method. The carbon microstructures are tunable with micro- and mesopore size distribution and a large specific surface area (1628.9-2146.1 m2 g-1). Furthermore, a significant morphology change, from carbon granules to carbon nanosheets, occurred at an annealing temperature of 1273 K. The unique carbon sheet morphology guaranteed a good specific capacitance of 246.4 F g-1 at 0.5 A g-1 in 1 M H2SO4 aqueous solution and an excellent rate capability with a retention of 87.9% at 5 A g-1 as coin cell. The outstanding capacitance attributes to the combination of pseudocapacitance due to the N,O dual-doping and unique nanosheet morphology. Moreover, its outstanding cycling performance with 95% retention over 10,000 cycles at 10 A g-1 and an acceptable energy density of 8.6 Wh kg-1 at 0.2 A g-1 make the N,O-codoped carbon nanosheet potent and promising electrode material for high performance supercapacitors.

  2. Iminodiacetic acid functionalized polypyrrole modified electrode as Pb(II) sensor: Synthesis and DPASV studies

    International Nuclear Information System (INIS)

    Joseph, Alex; Subramanian, Sankaran; Ramamurthy, Praveen C.; Sampath, Srinivasan; Kumar, R. Vasant; Schwandt, Carsten

    2014-01-01

    Graphical abstract: - Abstract: An electrochemical lead ion sensor has been developed by modification of carbon paste electrode (CPE) using polypyrrole functionalized with iminodiacetic acid (IDA-PPy) containing carboxyl group. The electrochemical response of Pb 2+ ion on the IDA-PPy modified CPE has been evaluated and the controling parameters have been optimized using differential pulse anodic stripping voltammetry (DPASV). The IDA-PPy modified CPE shows a linear correlation for Pb 2+ concentrations in the range of 1 × 10 −6 to 5 × 10 −9 M and the lower detection limit of Pb 2+ has been found to be 9.6 × 10 −9 M concentration. Other tested metal ions, namely Cu 2+ , Cd 2+ , Co 2+ , Hg 2+ , Ni 2+ and Zn 2+ , do not exhibit any voltammetric stripping response below 1 × 10 −7 M concentration. However, the Pb 2+ response is affected in the presence of molar equivalents or higher concentrations of Cu 2+ , Cd 2+ and Co 2+ ions in binary systems with Pb 2+ , consequent to their ability to bind with iminodiacetic acid, while Hg 2+ , Ni 2+ and Zn 2+ do not interfere at all. A good correlation has been observed between the lead concentrations as analyzed by DPASV using IDA-PPy modified CPE and atomic absorption spectrophotometry for a lead containing industrial effluent sample

  3. A survey of reference electrodes for high temperature waters

    International Nuclear Information System (INIS)

    Molander, A.; Eriksson, Sture; Pein, K.

    2000-11-01

    In nuclear power plants, corrosion potential measurements are used to follow the conditions for different corrosion types in reactor systems, particularly IGSCC in BWRs. The goal of this work has been to give a survey of reference electrodes for high temperature water, both those that are used for nuclear environments and those that are judged to possible future development. The reference electrodes that are used today in nuclear power plants for corrosion potential measurements are of three types. Silver chloride electrodes, membrane electrodes and platinum electrodes (hydrogen electrodes). The principals for their function is described as well as the conversion of measured potentials to the SHE scale (Standard Hydrogen Electrode). Silver chloride electrodes consist of an inner reference system of silver chloride in equilibrium with a chloride solution. The silver chloride electrode is the most common reference electrode and can be used in several different systems. Platinum electrodes are usually more robust and are particularly suitable to use in BWR environment to follow the hydrogen dosage, but have limitations at low and no hydrogen dosage. Ceramic membrane electrodes can be with different types of internal reference system. They were originally developed for pH measurements in high temperature water. If pH is constant, the membrane electrode can be used as reference electrode. A survey of ceramic reference electrodes for high temperature water is given. A ceramic membrane of the type used works as an oxygen conductor, so the potential and pH in surrounding medium is in equilibrium with the internal reference system. A survey of the lately development of electrodes is presented in order to explain why the different types of electrodes are developed as well as to give a background to the possibilities and limitations with the different electrodes. Possibilities of future development of electrodes are also given. For measurements at low or no hydrogen dosage

  4. Polystyrene-block-Poly(ionic liquid) Copolymers as Work Function Modifiers in Inverted Organic Photovoltaic Cells.

    Science.gov (United States)

    Park, Jong Baek; Isik, Mehmet; Park, Hea Jung; Jung, In Hwan; Mecerreyes, David; Hwang, Do-Hoon

    2018-02-07

    Interfacial layers play a critical role in building up the Ohmic contact between electrodes and functional layers in organic photovoltaic (OPV) solar cells. These layers are based on either inorganic oxides (ZnO and TiO 2 ) or water-soluble organic polymers such as poly[(9,9-dioctyl-2,7-fluorene)-alt-(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)] and polyethylenimine ethoxylated (PEIE). In this work, we have developed a series of novel poly(ionic liquid) nonconjugated block copolymers for improving the performance of inverted OPV cells by using them as work function modifiers of the indium tin oxide (ITO) cathode. Four nonconjugated polyelectrolytes (n-CPEs) based on polystyrene and imidazolium poly(ionic liquid) (PSImCl) were synthesized by reversible addition-fragmentation chain transfer polymerization. The ratio of hydrophobic/hydrophilic block copolymers was varied depending on the ratio of polystyrene to the PSImCl block. The ionic density, which controls the work function of the electrode by forming an interfacial dipole between the electrode and the block copolymers, was easily tuned by simply changing the PSImCl molar ratio. The inverted OPV device with the ITO/PS 29 -b-PSImCl 60 cathode achieved the best power conversion efficiency (PCE) of 7.55% among the synthesized block copolymers, exhibiting an even higher PCE than that of the reference OPV device with PEIE (7.30%). Furthermore, the surface properties of the block copolymers films were investigated by contact angle measurements to explore the influence of the controlled hydrophobic/hydrophilic characters on the device performances.

  5. Functional Security Model: Managers Engineers Working Together

    Science.gov (United States)

    Guillen, Edward Paul; Quintero, Rulfo

    2008-05-01

    Information security has a wide variety of solutions including security policies, network architectures and technological applications, they are usually designed and implemented by security architects, but in its own complexity this solutions are difficult to understand by company managers and they are who finally fund the security project. The main goal of the functional security model is to achieve a solid security platform reliable and understandable in the whole company without leaving of side the rigor of the recommendations and the laws compliance in a single frame. This paper shows a general scheme of the model with the use of important standards and tries to give an integrated solution.

  6. Specific and reversible immobilization of proteins tagged to the affinity polypeptide C-LytA on functionalized graphite electrodes.

    Directory of Open Access Journals (Sweden)

    Daniel Bello-Gil

    Full Text Available We have developed a general method for the specific and reversible immobilization of proteins fused to the choline-binding module C-LytA on functionalized graphite electrodes. Graphite electrode surfaces were modified by diazonium chemistry to introduce carboxylic groups that were subsequently used to anchor mixed self-assembled monolayers consisting of N,N-diethylethylenediamine groups, acting as choline analogs, and ethanolamine groups as spacers. The ability of the prepared electrodes to specifically bind C-LytA-tagged recombinant proteins was tested with a C-LytA-β-galactosidase fusion protein. The binding, activity and stability of the immobilized protein was evaluated by electrochemically monitoring the formation of an electroactive product in the enzymatic hydrolysis of the synthetic substrate 4-aminophenyl β-D-galactopyranoside. The hybrid protein was immobilized in an specific and reversible way, while retaining the catalytic activity. Moreover, these functionalized electrodes were shown to be highly stable and reusable. The method developed here can be envisaged as a general, immobilization procedure on the protein biosensor field.

  7. Specific and Reversible Immobilization of Proteins Tagged to the Affinity Polypeptide C-LytA on Functionalized Graphite Electrodes

    Science.gov (United States)

    Bello-Gil, Daniel; Maestro, Beatriz; Fonseca, Jennifer; Feliu, Juan M.; Climent, Víctor; Sanz, Jesús M.

    2014-01-01

    We have developed a general method for the specific and reversible immobilization of proteins fused to the choline-binding module C-LytA on functionalized graphite electrodes. Graphite electrode surfaces were modified by diazonium chemistry to introduce carboxylic groups that were subsequently used to anchor mixed self-assembled monolayers consisting of N,N-diethylethylenediamine groups, acting as choline analogs, and ethanolamine groups as spacers. The ability of the prepared electrodes to specifically bind C-LytA-tagged recombinant proteins was tested with a C-LytA-β-galactosidase fusion protein. The binding, activity and stability of the immobilized protein was evaluated by electrochemically monitoring the formation of an electroactive product in the enzymatic hydrolysis of the synthetic substrate 4-aminophenyl β-D-galactopyranoside. The hybrid protein was immobilized in an specific and reversible way, while retaining the catalytic activity. Moreover, these functionalized electrodes were shown to be highly stable and reusable. The method developed here can be envisaged as a general, immobilization procedure on the protein biosensor field. PMID:24498237

  8. Electrochemical investigation of functionalized graphene aerogel with different amount of p-phenylenediamine as an advanced electrode material for supercapacitors

    Science.gov (United States)

    Gholipour-Ranjbar, Habib; Ganjali, Mohammad Reza; Norouzi, Parviz; Naderi, Hamid Reza

    2016-07-01

    Graphene aerogel has attracted great attention as a new and efficient electrode material for supercapacitors. It can be expected that functionalization of graphene aerogels can further improve their capability. In this study, graphene aerogel functionalized with different amount of p-phenylenediamine (PPD) and the effect of PPD amount on the supercapacitive performance of functionalized graphene aerogel (FGA) was investigated. Structural characterizations showed that PPD molecules initiated graphene aerogel sheets assembly into three-dimensional structures and also increasing PPD amount led to increase in surface area. Electrochemical investigations proved that the FGA with larger pore size showed enhanced supercapacitive performance compared with the FGA with smaller pore size. The optimized FGA-based electrode exhibited outstanding specific capacitance (SC) of 385 F g-1 at a discharge current density of 1 A g-1, good rate capability (215 F g-1 at 20 A g-1), and exceptionally high cyclic stability by displaying 25% increase in SC after 5000 cycle.

  9. Functionalized Solid Electrodes for Electrochemical Biosensing of Purine Nucleobases and Their Analogues: A Review

    Science.gov (United States)

    Sharma, Vimal Kumar; Jelen, Frantisek; Trnkova, Libuse

    2015-01-01

    Interest in electrochemical analysis of purine nucleobases and few other important purine derivatives has been growing rapidly. Over the period of the past decade, the design of electrochemical biosensors has been focused on achieving high sensitivity and efficiency. The range of existing electrochemical methods with carbon electrode displays the highest rate in the development of biosensors. Moreover, modification of electrode surfaces based on nanomaterials is frequently used due to their extraordinary conductivity and surface to volume ratio. Different strategies for modifying electrode surfaces facilitate electron transport between the electrode surface and biomolecules, including DNA, oligonucleotides and their components. This review aims to summarize recent developments in the electrochemical analysis of purine derivatives, as well as discuss different applications. PMID:25594595

  10. Functionalized Solid Electrodes for Electrochemical Biosensing of Purine Nucleobases and Their Analogues: A Review

    Czech Academy of Sciences Publication Activity Database

    Sharma, V.K.; Jelen, František; Trnková, L.

    2015-01-01

    Roč. 15, č. 1 (2015), s. 1564-1600 ISSN 1424-8220 Institutional support: RVO:68081707 Keywords : purine derivatives * electrochemistry of purines * carbon electrode Subject RIV: BO - Biophysics Impact factor: 2.033, year: 2015

  11. Functionalized Solid Electrodes for Electrochemical Biosensing of Purine Nucleobases and Their Analogues: A Review

    Directory of Open Access Journals (Sweden)

    Vimal Kumar Sharma

    2015-01-01

    Full Text Available Interest in electrochemical analysis of purine nucleobases and few other important purine derivatives has been growing rapidly. Over the period of the past decade, the design of electrochemical biosensors has been focused on achieving high sensitivity and efficiency. The range of existing electrochemical methods with carbon electrode displays the highest rate in the development of biosensors. Moreover, modification of electrode surfaces based on nanomaterials is frequently used due to their extraordinary conductivity and surface to volume ratio. Different strategies for modifying electrode surfaces facilitate electron transport between the electrode surface and biomolecules, including DNA, oligonucleotides and their components. This review aims to summarize recent developments in the electrochemical analysis of purine derivatives, as well as discuss different applications.

  12. Textile Electrodes Embedded in Clothing: A Practical Alternative to Traditional Surface Electromyography when Assessing Muscle Excitation during Functional Movements

    Directory of Open Access Journals (Sweden)

    Steffi L. Colyer, Polly M. McGuigan

    2018-03-01

    Full Text Available Textile electromyography (EMG electrodes embedded in clothing allow muscle excitation to be recorded in previously inaccessible settings; however, their ability to accurately and reliably measure EMG during dynamic tasks remains largely unexplored. To quantify the validity and reliability of textile electrodes, 16 recreationally active males completed two identical testing sessions, within which three functional movements (run, cycle and squat were performed twice: once wearing EMG shorts (measuring quadriceps, hamstrings and gluteals myoelectric activity and once with surface EMG electrodes attached to the vastus lateralis, biceps femoris and gluteus maximus. EMG signals were identically processed to provide average rectified EMG (normalized to walking and excitation length. Results were compared across measurement systems and demonstrated good agreement between the magnitude of muscle excitation when EMG activity was lower, but agreement was poorer when excitation was higher. The length of excitation bursts was consistently longer when measured using textile vs. surface EMG electrodes. Comparable between-session (day-to-day repeatability was found for average rectified EMG (mean coefficient of variation, CV: 42.6 and 41.2% and excitation length (CV: 12.9 and 9.8% when using textile and surface EMG, respectively. Additionally, similar within-session repeatability (CV was recorded for average rectified EMG (13.8 and 14.1% and excitation length (13.0 and 12.7% for textile and surface electrodes, respectively. Generally, textile EMG electrodes appear to be capable of providing comparable muscle excitation information and reproducibility to surface EMG during dynamic tasks. Textile EMG shorts could therefore be a practical alternative to traditional laboratory-based methods allowing muscle excitation information to be collected in more externally-valid training environments.

  13. Transparent Conducting Oxides for Photovoltaics: Manipulation of Fermi Level, Work Function and Energy Band Alignment

    Directory of Open Access Journals (Sweden)

    Diana E. Proffit

    2010-11-01

    Full Text Available Doping limits, band gaps, work functions and energy band alignments of undoped and donor-doped transparent conducting oxides Zn0, In2O3, and SnO2 as accessed by X-ray and ultraviolet photoelectron spectroscopy (XPS/UPS are summarized and compared. The presented collection provides an extensive data set of technologically relevant electronic properties of photovoltaic transparent electrode materials and illustrates how these relate to the underlying defect chemistry, the dependence of surface dipoles on crystallographic orientation and/or surface termination, and Fermi level pinning.

  14. Boron-doped diamond electrode: synthesis, characterization, functionalization and analytical applications.

    Science.gov (United States)

    Luong, John H T; Male, Keith B; Glennon, Jeremy D

    2009-10-01

    In recent years, conductive diamond electrodes for electrochemical applications have been a major focus of research and development. The impetus behind such endeavors could be attributed to their wide potential window, low background current, chemical inertness, and mechanical durability. Several analytes can be oxidized by conducting diamond compared to other carbon-based materials before the breakdown of water in aqueous electrolytes. This is important for detecting and/or identifying species in solution since oxygen and hydrogen evolution do not interfere with the analysis. Thus, conductive diamond electrodes take electrochemical detection into new areas and extend their usefulness to analytes which are not feasible with conventional electrode materials. Different types of diamond electrodes, polycrystalline, microcrystalline, nanocrystalline and ultrananocrystalline, have been synthesized and characterized. Of particular interest is the synthesis of boron-doped diamond (BDD) films by chemical vapor deposition on various substrates. In the tetrahedral diamond lattice, each carbon atom is covalently bonded to its neighbors forming an extremely robust crystalline structure. Some carbon atoms in the lattice are substituted with boron to provide electrical conductivity. Modification strategies of doped diamond electrodes with metallic nanoparticles and/or electropolymerized films are of importance to impart novel characteristics or to improve the performance of diamond electrodes. Biofunctionalization of diamond films is also feasible to foster several useful bioanalytical applications. A plethora of opportunities for nanoscale analytical devices based on conducting diamond is anticipated in the very near future.

  15. Accelerating the development of transparent graphene electrodes through basic science driven chemical functionalization.

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Calvin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Beechem, III, Thomas Edwin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ohta, Taisuke [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brumbach, Michael T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wheeler, David Roger [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Veneman, Alexander [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gearba, I. Raluca [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stevenson, Keith J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-09-01

    Chemical functionalization is required to adapt graphenes properties to many applications. However, most covalent functionalization schemes are spontaneous or defect driven and are not suitable for applications requiring directed assembly of molecules on graphene substrates. In this work, we demonstrated electrochemically driven covalent bonding of phenyl iodoniums onto epitaxial graphene. The amount of chemisorption was demonstrated by varying the duration of the electrochemical driving potential. Chemical, electronic, and defect states of phenyl-modified graphene were studied by photoemission spectroscopy, spatially resolved Raman spectroscopy, and water contact angle measurement. Covalent attachment rehybridized some of the delocalized graphene sp2 orbitals to localized sp3 states. Control over the relative spontaneity (reaction rate) of covalent graphene functionalization is an important first step to the practical realization of directed molecular assembly on graphene. More than 10 publications, conference presentations, and program highlights were produced (some invited), and follow-on funding was obtained to continue this work.

  16. Vertical electric field stimulated neural cell functionality on porous amorphous carbon electrodes.

    Science.gov (United States)

    Jain, Shilpee; Sharma, Ashutosh; Basu, Bikramjit

    2013-12-01

    We demonstrate the efficacy of amorphous macroporous carbon substrates as electrodes to support neuronal cell proliferation and differentiation in electric field mediated culture conditions. The electric field was applied perpendicular to carbon substrate electrode, while growing mouse neuroblastoma (N2a) cells in vitro. The placement of the second electrode outside of the cell culture medium allows the investigation of cell response to electric field without the concurrent complexities of submerged electrodes such as potentially toxic electrode reactions, electro-kinetic flows and charge transfer (electrical current) in the cell medium. The macroporous carbon electrodes are uniquely characterized by a higher specific charge storage capacity (0.2 mC/cm(2)) and low impedance (3.3 kΩ at 1 kHz). The optimal window of electric field stimulation for better cell viability and neurite outgrowth is established. When a uniform or a gradient electric field was applied perpendicular to the amorphous carbon substrate, it was found that the N2a cell viability and neurite length were higher at low electric field strengths (≤ 2.5 V/cm) compared to that measured without an applied field (0 V/cm). While the cell viability was assessed by two complementary biochemical assays (MTT and LDH), the differentiation was studied by indirect immunostaining. Overall, the results of the present study unambiguously establish the uniform/gradient vertical electric field based culture protocol to either enhance or to restrict neurite outgrowth respectively at lower or higher field strengths, when neuroblastoma cells are cultured on porous glassy carbon electrodes having a desired combination of electrochemical properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Executive Functions and Working Memory Behaviours in Children with a Poor Working Memory

    Science.gov (United States)

    St. Clair-Thompson, Helen L.

    2011-01-01

    Previous research has suggested that working memory difficulties play an integral role in children's underachievement at school. However, working memory is just one of several executive functions. The extent to which problems in working memory extend to other executive functions is not well understood. In the current study 38 children with a poor…

  18. Adsorptive stripping voltammetric determination of nitroimidazole derivative on multiwalled carbon nanotube modified electrodes: influence of size and functionalization of nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Jara-Ulloa, Paola; Canete-Rosales, Paulina; Nunez-Vergara, Luis J; Squella, Juan A., E-mail: asquella@ciq.uchile.c [University of Chile, Santiago (Chile). Chemical and Pharmaceutical Sciences Faculty. Bioelectrochemistry Lab.

    2011-07-01

    1-Methyl-4-nitro-2-bromine methylimidazole (4-NimMeBr), was electrochemically reduced on mercury, glassy carbon and multiwalled carbon nanotubes (MWCNT) modified electrodes. 4-NimMeBr was adsorbed on the MWCNT modified electrode thus permitting the implementation of an adsorptive stripping voltammetric (ASV) method. We have used 4-NimMeBr as a prototype electroactive nitro compound to study the effect of both the size of the nanotubes and its functionalization by oxidation. The oxidized MWCNT forms better dispersions than the non-oxidized, producing electrode surface with higher density of MWCNT as was determined by electrochemical mapping using scanning electrochemical microscopy (SECM). Under the optimized conditions, the peak current was proportional to the concentration of 4-NimMeBr in the range of 10{sup -6} mol L{sup -1} to 10{sup -4} mol L{sup -1} with detection and quantification limits of 4.41 x 10{sup -6} mol L{sup -1} and 6.21 x 10{sup -6} mol L{sup -1}, respectively. The sensibility of bare electrode was 0.01 {mu}A per mmol L{sup -1}, which was lower than the value of 5.34 and 6.97 mA per mmol L{sup -1} obtained using short and large oxidized MWCNT, respectively. (author)

  19. Protections of bovine serum albumin protein from damage on functionalized graphene-based electrodes by flavonoids.

    Science.gov (United States)

    Sun, Bolu; Gou, Yuqiang; Xue, Zhiyuan; Zheng, Xiaoping; Ma, Yuling; Hu, Fangdi; Zhao, Wanghong

    2016-05-01

    A sensitive electrochemical sensor based on bovine serum albumin (BSA)/poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene nanosheets (PDDA-G) composite film modified glassy carbon electrode (BSA/PDDA-G/GCE) had been developed to investigate the oxidative protein damage and protections of protein from damage by flavonoids. The performance of this sensor was remarkably improved due to excellent electrical conductivity, strong adsorptive ability, and large effective surface area of PDDA-G. The BSA/PDDA-G/GCE displayed the greatest degree of BSA oxidation damage at 40 min incubation time and in the pH 5.0 Fenton reagent system (12.5 mM FeSO4, 50 mM H2O2). The antioxidant activities of four flavonoids had been compared by fabricated sensor based on the relative peak current ratio of SWV, because flavonoids prevented BSA damage caused by Fenton reagent and affected the BSA signal in a solution containing Co(bpy)3(3+). The sensor was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). UV-vis spectrophotometry and FTIR were also used to investigate the generation of hydroxyl radical and BSA damage, respectively. On the basis of results from electrochemical methods, the order of the antioxidant activities of flavonoids is as follows: (+)-catechin>kaempferol>apigenin>naringenin. A novel, direct SWV analytical method for detection of BSA damage and assessment of the antioxidant activities of four flavonoids was developed and this electrochemical method provided a simple, inexpensive and rapid detection of BSA damage and evaluation of the antioxidant activities of samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Alizarin red S functionalized mesoporous silica modified glassy carbon electrode for electrochemical determination of anthracene

    International Nuclear Information System (INIS)

    Liu, Shan; Wei, Maochao; Zheng, Xiangli; Xu, Shuai; Xia, Fangquan; Zhou, Changli

    2015-01-01

    Highlights: • Alizarin red S-SBA15 composite was prepared and characterized. • A novel sensing platform was constructed for anthracene determination. • The proposed sensor exhibited high sensitivity and low detection limit for detecting anthracene. • This method can be applied to the practical detection of anthracene in waste water. - Abstract: In the paper, a novel and sensitive electrochemical sensor based on modification of electroactive alizarin red S functionalized mesoporous silica material SBA15 onto glassy carbon electrode (ARS-SBA15/GCE) was developed. Alizarin red S, called electrochemical probe that can selectively recognize polycyclic aromatic hydrocarbons (PAHs), as tools for the detection of tricyclic aromatic hydrocarbon anthracene. The morphology and interface property of ARS modified SBA15 (ARS-SBA15) were examined by transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR). Taking advantage of the π-π stacking force between alizarin red S and anthracene, the ARS-SBA15/GCE sensor could detect anthracene quantitatively in a wide range of 1.0 pM–10.0 nM and a low detection limit of 0.5 pM (S/N = 3). Other PAHs, such as naphthalene, phenanthrene, pyrene, and benzo[a]pyrene show little interference on the detection. Consequently, a simple and sensitive electrochemical method was proposed for the determination of anthracene, which can be used to determine anthracene in waste water samples. The electrochemical method provides a general tool that complements the commonly used spectroscopic methods and immune method for the detection of PAHs

  1. Protections of bovine serum albumin protein from damage on functionalized graphene-based electrodes by flavonoids

    International Nuclear Information System (INIS)

    Sun, Bolu; Gou, Yuqiang; Xue, Zhiyuan; Zheng, Xiaoping; Ma, Yuling; Hu, Fangdi; Zhao, Wanghong

    2016-01-01

    A sensitive electrochemical sensor based on bovine serum albumin (BSA)/poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene nanosheets (PDDA-G) composite film modified glassy carbon electrode (BSA/PDDA-G/GCE) had been developed to investigate the oxidative protein damage and protections of protein from damage by flavonoids. The performance of this sensor was remarkably improved due to excellent electrical conductivity, strong adsorptive ability, and large effective surface area of PDDA-G. The BSA/PDDA-G/GCE displayed the greatest degree of BSA oxidation damage at 40 min incubation time and in the pH 5.0 Fenton reagent system (12.5 mM FeSO_4, 50 mM H_2O_2). The antioxidant activities of four flavonoids had been compared by fabricated sensor based on the relative peak current ratio of SWV, because flavonoids prevented BSA damage caused by Fenton reagent and affected the BSA signal in a solution containing Co(bpy)_3"3"+. The sensor was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). UV–vis spectrophotometry and FTIR were also used to investigate the generation of hydroxyl radical and BSA damage, respectively. On the basis of results from electrochemical methods, the order of the antioxidant activities of flavonoids is as follows: (+)-catechin > kaempferol > apigenin > naringenin. A novel, direct SWV analytical method for detection of BSA damage and assessment of the antioxidant activities of four flavonoids was developed and this electrochemical method provided a simple, inexpensive and rapid detection of BSA damage and evaluation of the antioxidant activities of samples. - Highlights: • Hydroxyl radicals were produced by Fenton reagents. • An electrochemical bovine serum albumin (BSA) damage sensor was successfully fabricated. • The proposed biosensor can assess the antioxidant capacity of four flavonoids. • The order of antioxidant activities of flavonoids is

  2. Protections of bovine serum albumin protein from damage on functionalized graphene-based electrodes by flavonoids

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Bolu [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China); Gou, Yuqiang [Lanzhou Military Command Center for Disease Prevention and Control, Lanzhou 730000 (China); Xue, Zhiyuan; Zheng, Xiaoping; Ma, Yuling [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China); Hu, Fangdi, E-mail: hufd@lzu.edu.cn [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China); Zhao, Wanghong, E-mail: wanghongzhao@sina.com [Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou 51515 (China)

    2016-05-01

    A sensitive electrochemical sensor based on bovine serum albumin (BSA)/poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene nanosheets (PDDA-G) composite film modified glassy carbon electrode (BSA/PDDA-G/GCE) had been developed to investigate the oxidative protein damage and protections of protein from damage by flavonoids. The performance of this sensor was remarkably improved due to excellent electrical conductivity, strong adsorptive ability, and large effective surface area of PDDA-G. The BSA/PDDA-G/GCE displayed the greatest degree of BSA oxidation damage at 40 min incubation time and in the pH 5.0 Fenton reagent system (12.5 mM FeSO{sub 4}, 50 mM H{sub 2}O{sub 2}). The antioxidant activities of four flavonoids had been compared by fabricated sensor based on the relative peak current ratio of SWV, because flavonoids prevented BSA damage caused by Fenton reagent and affected the BSA signal in a solution containing Co(bpy){sub 3}{sup 3+}. The sensor was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). UV–vis spectrophotometry and FTIR were also used to investigate the generation of hydroxyl radical and BSA damage, respectively. On the basis of results from electrochemical methods, the order of the antioxidant activities of flavonoids is as follows: (+)-catechin > kaempferol > apigenin > naringenin. A novel, direct SWV analytical method for detection of BSA damage and assessment of the antioxidant activities of four flavonoids was developed and this electrochemical method provided a simple, inexpensive and rapid detection of BSA damage and evaluation of the antioxidant activities of samples. - Highlights: • Hydroxyl radicals were produced by Fenton reagents. • An electrochemical bovine serum albumin (BSA) damage sensor was successfully fabricated. • The proposed biosensor can assess the antioxidant capacity of four flavonoids. • The order of antioxidant

  3. Voltammetry and Electrocatalysis of Achrornobacter Xylosoxidans Copper Nitrite Reductase on Functionalized Au(111)-Electrode Surfaces

    DEFF Research Database (Denmark)

    Welinder, Anna C.; Zhang, Jingdong; Hansen, Allan G.

    2007-01-01

    A long-standing issue in protein film voltammetry (PFV), particularly electrocatalytic voltammetry of redox enzyme monolayers, is the variability of protein adsorption modes, reflected in distributions of catalytic activity of the adsorbed protein/enzyme molecules. Use of well-defined, atomically...... planar electrode surfaces is a step towards the resolution of this central issue. We report here the voltammetry of copper nitrite reductase (CNiR, Achromobacter xylosoxidons) on Au(111)-electrode surfaces modified by monolayers of a broad variety of thiol-based linker molecules. These represent......NiR thus shows highly efficient, close to ideal reversible electrocatalytic voltammetry on cysteamine-covered Au(111)-electrode surfaces, most likely due to two cysteamine orientations previously disclosed by in situ scanning tunnelling microscopy. Such a dual orientation exposes both a hydrophobic...

  4. Work function of elemental metals and its face dependence ...

    African Journals Online (AJOL)

    The calculated work functions for the flat surface of the metals were in perfect agreement with experimental values for metals in the low-density limit and the agreement with experimental values decreased towards the high-density limit. The calculated work functions for the body centred cubic metals were in good agreement ...

  5. Bulk-plasmon contribution to the work function of metals

    International Nuclear Information System (INIS)

    Gutierrez, F A; DIaz-Valdes, J; Jouin, H

    2007-01-01

    By consideration of the Koopmans theorem expression for the work function of a metal, we find that the total height of the surface barrier potential equals the value of the bulk-plasmon energy of pure metals. As a consequence a simple formula for the work function is obtained which shows better agreement with the experimental data than the most complete existent theories

  6. Work function in niobium, tantalum and vanadium hydrides

    International Nuclear Information System (INIS)

    Kucherov, Ya.R.; Markin, V.Ya.; Savin, V.I.; Topil'skij, N.D.

    1978-01-01

    The concentration dependences of the work function of electrons in hydrides of Nb, Ta and V are presented. The work function of electrons was studied at room temperature by the contact Kelvin potential difference method to an accuracy of +-0.02 eV. The effect of hydrogen on the work function variations in the systems investigated has been analyzed. It is shown that a higher hydrogen concentration in solid solutions based on the Nb-H and Ta-H systems increases the effective total positive dipole moment, whereby the work function decreases. The abnormal changes in the work function in the region of solid solutions of hydrogen in vanadium seem to be due to the specific electronic structure of vanadium and its interaction with hydrogen

  7. An improved method for direct estimation of free cyanide in drinking water by Ion Chromatography-Pulsed Amperometry Detection (IC-PAD) on gold working electrode.

    Science.gov (United States)

    Kumar Meher, Alok; Labhsetwar, Nitin; Bansiwal, Amit

    2018-02-01

    In the present work a fast, reliable and safe Ion Exchange Chromatography-Pulsed Amperometry Detection (IC-PAD) method for direct determination of free cyanide in drinking water has been reported. To the best of our knowledge for the first time we are reporting the application of Gold working electrode for detection of free cyanide in a chromatography system. The system shows a wide linear range up to 8000µg/L. The electrode was found to have improved sensitivity and selectivity in the presence of interfering ions. The detection limit of the system was calculated to be 2µg/L. Long term evaluation of the electrode was found to be stable. Reproducible results were obtained from analysis of drinking water samples with recoveries of 98.3-101.2% and Relative Standard Deviations (RSD) of cyanide in drinking water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A comparison study of electrodes for neonate electrical impedance tomography

    International Nuclear Information System (INIS)

    Rahal, Mohamad; Demosthenous, Andreas; Khor, Joo Moy; Tizzard, Andrew; Bayford, Richard

    2009-01-01

    Electrical impedance tomography (EIT) is an imaging technique that has the potential to be used for studying neonate lung function. The properties of the electrodes are very important in multi-frequency EIT (MFEIT) systems, particularly for neonates, as the skin cannot be abraded to reduce contact impedance. In this work, the impedance of various clinical electrodes as a function of frequency is investigated to identify the optimum electrode type for this application. Six different types of self-adhesive electrodes commonly used in general and neonatal cardiology have been investigated. These electrodes are Ag/AgCl electrodes from the Ambu® Cardiology Blue sensors range (BR, NF and BRS), Kendall (KittyCat(TM) and ARBO®) and Philips 13953D electrodes. In addition, a textile electrode without gel from Textronics was tested on two subjects to allow comparison with the hydrogel-based electrodes. Two- and four-electrode measurements were made to determine the electrode-interface and tissue impedances, respectively. The measurements were made on the back of the forearm of six healthy adult volunteers without skin preparation with 2.5 cm electrode spacing. Impedance measurements were carried out using a Solartron SI 1260 impedance/gain-phase analyser with a frequency range from 10 Hz to 1 MHz. For the electrode-interface impedance, the average magnitude decreased with frequency, with an average value of 5 kΩ at 10 kHz and 337 Ω at 1 MHz; for the tissue impedance, the respective values were 987 Ω and 29 Ω. Overall, the Ambu BRS, Kendall ARBO® and Textronics textile electrodes gave the lowest electrode contact impedance at 1 MHz. Based on the results of the two-electrode measurements, simple RC models for the Ambu BRS and Kendall-ARBO and Textronics textile electrodes have been derived for MFEIT applications

  9. Cyanide adsorption on gold electrodes : a combined surface enhanced Raman spectroscopy and density functional theory study

    NARCIS (Netherlands)

    Beltramo, G.L.; Shubina, T.E.; Mitchell, S.J.; Koper, M.T.M.

    2004-01-01

    A combined SERS and DFT study of cyanide adsorption on a gold electrode is presented. From our analysis, the high-frequency mode at 2100 cm-1 is ascribed to the C–N stretching frequency at (1 0 0) and (1 1 0) sites. The lower frequency modes at 370 and 300 cm-1 are ascribed to the Au–CN stretching

  10. Pseudocapacitive organic catechol derivative-functionalized three-dimensional graphene aerogel hybrid electrodes for high-performance supercapacitors

    Science.gov (United States)

    Choi, Jaewon; Yang, MinHo; Kim, Sung-Kon

    2017-11-01

    Bio-inspired and environmentally friendly chemical functionalization is a successful way to a new class of hybrid electrode materials for applications in energy storage. Quinone (Q)-hydroquinone (QH2) couples, a prototypical example of organic redox systems, provide fast and reversible proton-coupled electron-transfer reactions which lead to increased capacity. To achieve high capacitance and rate performance, constructing three-dimensional (3D) continuous porous structure is highly desirable. Here we report the hybrid electrodes (GA-C) consisting of 3D graphene aerogel (GA) functionalized with organic redox-active material, catechol derivative, for application to high-performance supercapacitors. The catechol derivative is adsorbed on the surface of GA through non-covalent interactions and promotes fast and reversible Q/QH2 faradaic reactions, providing large specific capacitance of 188 F g-1 at a current of 1 A g-1 and a specific energy of ∼25 Wh kg-1 at a specific power of ∼18,000 W kg-1. 3D continuous porous structure of GA electrode facilitates ion and electron transports, resulting in high rate performance (∼140 F g-1 at a current of 10 A g-1).

  11. Functionalized-graphene modified graphite electrode for the selective determination of dopamine in presence of uric acid and ascorbic acid.

    Science.gov (United States)

    Mallesha, Malledevaru; Manjunatha, Revanasiddappa; Nethravathi, C; Suresh, Gurukar Shivappa; Rajamathi, Michael; Melo, Jose Savio; Venkatesha, Thimmappa Venkatarangaiah

    2011-06-01

    Graphene is chemically synthesized by solvothermal reduction of colloidal dispersions of graphite oxide. Graphite electrode is modified with functionalized-graphene for electrochemical applications. Electrochemical characterization of functionalized-graphene modified graphite electrode (FGGE) is carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The behavior of FGGE towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) has been investigated by CV, differential pulse voltammetry (DPV) and chronoamperommetry (CA). The FGGE showed excellent catalytic activity towards electrochemical oxidation of AA, DA and UA compared to that of the bare graphite electrode. The electrochemical oxidation signals of AA, DA and UA are well separated into three distinct peaks with peak potential separation of 193mv, 172mv and 264mV between AA-DA, DA-UA and AA-UA respectively in CV studies and the corresponding peak potential separations in DPV mode are 204mv, 141mv and 345mv. The FGGE is successfully used for the simultaneous detection of AA, DA and UA in their ternary mixture and DA in serum and pharmaceutical samples. The excellent electrocatalytic behavior of FGGE may lead to new applications in electrochemical analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Enhancing the efficiency of dye-sensitized solar cells by adding diatom frustules into TiO{sub 2} working electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Der-Ray, E-mail: derray@mail.ndhu.edu.tw; Jiang, Yan-Jang; Liou, Run-Lin; Chen, Chih-Han; Chen, Yi-An; Tsai, Chih-Hung, E-mail: cht@mail.ndhu.edu.tw

    2015-08-30

    Graphical abstract: - Highlights: • High-speed centrifugal processing and sedimentation-rate separation techniques were used to obtain diatom frustules. • Diatom frustules were added into TiO{sub 2} paste to prepare a TiO{sub 2}-diatom paste mixture. • TiO{sub 2}-diatom paste mixture was used to fabricate working electrodes for DSSCs. • TiO{sub 2}-diatom electrodes improved the light-trapping effect and DSSC efficiency. • DSSCs with using the TiO{sub 2}-diatom electrode exhibited a 38% increase in efficiency. - Abstract: In this study, diatom frustules were added into TiO{sub 2} paste to prepare a TiO{sub 2}-diatom paste mixture. Spin-coating and high-temperature sintering techniques were then used to fabricate working electrodes for dye-sensitized solar cells (DSSCs). Mixing the diatom frustules with the TiO{sub 2} paste improved the light-trapping effect and scattering properties of the incident light in the TiO{sub 2}-diatom working electrodes, thereby enhancing the power conversion efficiency of the DSSCs. In this study, a high-speed centrifugal processing technology and sedimentation-rate separation techniques were first used to obtain the diatom frustules, which were then mixed with the TiO{sub 2} paste at a weight ratio of 1:50; a spin-coating technique was then used to fabricate the working electrodes. Finally, a high-temperature sintering process (500 °C) was performed. In this study, optical microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and a surface profiler and spectrometer were used to analyze the characteristics of the working electrodes. The TiO{sub 2} or TiO{sub 2}-diatom working electrodes were prepared under various spin-coating conditions for fabricating and analyzing the characteristics of the DSSCs. The results indicated that under identical conditions, the power conversion efficiency of the DSSCs was 3.81% when coated three times with a conventional TiO{sub 2

  13. Dye-sensitized solar cell with energy storage function through PVDF/ZnO nanocomposite counter electrode.

    Science.gov (United States)

    Zhang, Xi; Huang, Xuezhen; Li, Chensha; Jiang, Hongrui

    2013-08-14

    Dye-sensitized solar cells with an energy storage function are demonstrated by modifying its counter electrode with a poly (vinylidene fluoride)/ZnO nanowire array composite. This simplex device could still function as an ordinary solar cell with a steady photocurrent output even after being fully charged. An energy storage density of 2.14 C g(-1) is achieved, while simultaneously a 3.70% photo-to-electric conversion efficiency is maintained. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Impaired work functioning due to common mental disorders in nurses and allied health professionals: the Nurses Work Functioning Questionnaire.

    Science.gov (United States)

    Gärtner, F R; Nieuwenhuijsen, K; van Dijk, F J H; Sluiter, J K

    2012-02-01

    Common mental disorders (CMD) negatively affect work functioning. In the health service sector not only the prevalence of CMDs is high, but work functioning problems are associated with a risk of serious consequences for patients and healthcare providers. If work functioning problems due to CMDs are detected early, timely help can be provided. Therefore, the aim of this study is to develop a detection questionnaire for impaired work functioning due to CMDs in nurses and allied health professionals working in hospitals. First, an item pool was developed by a systematic literature study and five focus group interviews with employees and experts. To evaluate the content validity, additional interviews were held. Second, a cross-sectional assessment of the item pool in 314 nurses and allied health professionals was used for item selection and for identification and corroboration of subscales by explorative and confirmatory factor analysis. The study results in the Nurses Work Functioning Questionnaire (NWFQ), a 50-item self-report questionnaire consisting of seven subscales: cognitive aspects of task execution, impaired decision making, causing incidents at work, avoidance behavior, conflicts and irritations with colleagues, impaired contact with patients and their family, and lack of energy and motivation. The questionnaire has a proven high content validity. All subscales have good or acceptable internal consistency. The Nurses Work Functioning Questionnaire gives insight into precise and concrete aspects of impaired work functioning of nurses and allied health professionals. The scores can be used as a starting point for purposeful interventions.

  15. Surface energy and work function of elemental metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Rosengaard, N. M.

    1992-01-01

    and noble metals, as derived from the surface tension of liquid metals. In addition, they give work functions which agree with the limited experimental data obtained from single crystals to within 15%, and explain the smooth behavior of the experimental work functions of polycrystalline samples......We have performed an ab initio study of the surface energy and the work function for six close-packed surfaces of 40 elemental metals by means of a Green’s-function technique, based on the linear-muffin-tin-orbitals method within the tight-binding and atomic-sphere approximations. The results...... are in excellent agreement with a recent full-potential, all-electron, slab-supercell calculation of surface energies and work functions for the 4d metals. The present calculations explain the trend exhibited by the surface energies of the alkali, alkaline earth, divalent rare-earth, 3d, 4d, and 5d transition...

  16. Strain engineering the work function in monolayer metal dichalcogenides

    International Nuclear Information System (INIS)

    Lanzillo, Nicholas A; Simbeck, Adam J; Nayak, Saroj K

    2015-01-01

    We use first-principles density functional theory to investigate the effect of both tensile and compressive strain on the work functions of various metal dichalcogenide monolayers. We find that for all six species considered, including MoS 2 , WS 2 , SnS 2 , VS 2 , MoSe 2 and MoTe 2 , that compressive strain of up to 10% decreases the work function continuously by as much as 1.0 eV. Large enough tensile strain is also found to decrease the work function, although in some cases we observe an increase in the work function for intermediate values of tensile strain. This work function modulation is attributed to a weakening of the chalcogenide-metal bonds and an increase in total energy of each system as a function of strain. Values of strain which bring the metal atoms closer together lead to an increase in electrostatic potential energy, which in turn results in an increase in the vacuum potential level. The net effect on the work function can be explained in terms of the balance between the increases in the vacuum potential levels and Fermi energy. (paper)

  17. Towards a sustainable healthy working life : associations between chronological age, functional age and work outcomes

    NARCIS (Netherlands)

    Koolhaas, Wendy; van der Klink, Jac J. L.; Groothoff, Johan W.; Brouwer, Sandra

    Background: The aims of this study were: (i) to determine the relation between chronological and functional age; (ii) to examine the association between chronological age and work outcomes; and (iii) to examine the association between functional age and work outcomes. An overview of the most

  18. Lung function changes in wildland firefighters working at prescribed burns.

    Energy Technology Data Exchange (ETDEWEB)

    Adetona, Olorunfemi; Hall, Daniel, B.; Naeher, L,P.

    2011-10-01

    Although decline in lung function across workshift has been observed in wildland firefighters, measurements have been restricted to days when they worked at fires. Consequently, such results could have been confounded by normal circadian variation associated with lung function. We investigated the across-shift changes in lung function of wildland firefighters, and the effect of cumulative exposure on lung function during the burn season.

  19. Image-potential states and work function of graphene

    International Nuclear Information System (INIS)

    Niesner, Daniel; Fauster, Thomas

    2014-01-01

    Image-potential states of graphene on various substrates have been investigated by two-photon photoemission and scanning tunneling spectroscopy. They are used as a probe for the graphene-substrate interaction and resulting changes in the (local) work function. The latter is driven by the work function difference between graphene and the substrate. This results in a charge transfer which also contributes to core-level shifts in x-ray photoemission. In this review article, we give an overview over the theoretical models and the experimental data for image-potential states and work function of graphene on various substrates. (topical review)

  20. Photoelectric work function studies of carbonaceous films containing Ni nanocrystals

    International Nuclear Information System (INIS)

    Czerwosz, E.; Dluzewski, P.; Kutner, T.; Stacewicz, T.

    2003-01-01

    In this paper we present the results of photoelectric work function measurements for carbonaceous films containing Ni nanocrystals. The investigated films were obtained by thermal vacuum deposition method. The structure of films was studied by electron diffraction, transmission microscopy and Raman spectroscopy. Film structure depends on Ni contents in the film volume. Work function determined from photoelectric measurements for all investigated films are similar and lie in the range of 2.65-2.93 eV. The decrease of work function value with the cleaning of the film's surface with UV pulsed laser beam was observed

  1. Double functions of porous TiO2 electrodes on CH3NH3PbI3 perovskite solar cells: Enhancement of perovskite crystal transformation and prohibition of short circuiting

    Directory of Open Access Journals (Sweden)

    Govindhasamy Murugadoss

    2014-08-01

    Full Text Available In order to analyze the crystal transformation from hexagonal PbI2 to CH3NH3PbI3 by the sequential (two-step deposition process, perovskite CH3NH3PbI3 layers were deposited on flat and/or porous TiO2 layers. Although the narrower pores using small nanoparticles prohibited the effective transformation, the porous-TiO2 matrix was able to help the crystal transformation of PbI2 to CH3NH3PbI3 by sequential two-step deposition. The resulting PbI2 crystals in porous TiO2 electrodes did not deteriorate the photovoltaic effects. Moreover, it is confirmed that the porous TiO2 electrode had served the function of prohibiting short circuits between working and counter electrodes in perovskite solar cells.

  2. Multiple enhancement of luminol electrochemiluminescence using electrodes functionalized with titania nanotubes and platinum black: ultrasensitive determination of hydrogen peroxide, resveratrol, and dopamine

    International Nuclear Information System (INIS)

    Ming, Liang; Peng, Tingting; Tu, Yifeng

    2016-01-01

    We describe a substantial improvement of the electrochemiluminescence (ECL) of luminol which is widely used in flow injection analysis (FIA). It is based on synchronous dual sensitization of ECL by using titania nanotubes (TiNTs) and platinum black (PB). A piece of indium tin oxide (ITO) glass functionalized with TiNTs acts as the first working electrode, and a PB-modified platinum plate serves as the second one. By applying two constant potentials to the two electrodes, strong and consecutive ECL emission of luminol is obtained. The system works well in assays as shown for the successful quantitation of hydrogen peroxide (H 2 O 2 ), of the antioxidant resveratrol, and of the neutrotransmitter dopamine (DA) in spiked human serum samples. The detection limits for these three species (at a signal-to-noise ratio of 3) are as low as 66 pM (H 2 O 2 ), 22 nM (resveratrol), and 30 nM (DA). Recoveries in assays of DA in spiked serum range from 97.3 to 105.4 %. In our perception, the technique of dual sensitization represents a substantial improvement of the detection limits of ECL assays. (author)

  3. In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry

    Energy Technology Data Exchange (ETDEWEB)

    Young, Matthias J.; Bedford, Nicholas M.; Jiang, Naisheng; Lin, Deqing; Dai, Liming

    2017-05-26

    The ability to generate new electrochemically active materials for energy generation and storage with improved properties will likely be derived from an understanding of atomic-scale structure/function relationships during electrochemical events. Here, the design and implementation of a new capillary electrochemical cell designed specifically forin situhigh-energy X-ray diffraction measurements is described. By increasing the amount of electrochemically active material in the X-ray path while implementing low-Zcell materials with anisotropic scattering profiles, an order of magnitude enhancement in diffracted X-ray signal over traditional cell geometries for multiple electrochemically active materials is demonstrated. This signal improvement is crucial for high-energy X-ray diffraction measurements and subsequent Fourier transformation into atomic pair distribution functions for atomic-scale structural analysis. As an example, clear structural changes in LiCoO2under reductive and oxidative conditions using the capillary cell are demonstrated, which agree with prior studies. Accurate modeling of the LiCoO2diffraction data using reverse Monte Carlo simulations further verifies accurate background subtraction and strong signal from the electrochemically active material, enabled by the capillary working electrode geometry.

  4. Doped graphene electrodes for organic solar cells

    International Nuclear Information System (INIS)

    Park, Hyesung; Kim, Ki Kang; Bulovic, Vladimir; Kong, Jing; Rowehl, Jill A

    2010-01-01

    In this work graphene sheets grown by chemical vapor deposition (CVD) with controlled numbers of layers were used as transparent electrodes in organic photovoltaic (OPV) devices. It was found that for devices with pristine graphene electrodes, the power conversion efficiency (PCE) is comparable to their counterparts with indium tin oxide (ITO) electrodes. Nevertheless, the chances for failure in OPVs with pristine graphene electrodes are higher than for those with ITO electrodes, due to the surface wetting challenge between the hole-transporting layer and the graphene electrodes. Various alternative routes were investigated and it was found that AuCl 3 doping on graphene can alter the graphene surface wetting properties such that a uniform coating of the hole-transporting layer can be achieved and device success rate can be increased. Furthermore, the doping both improves the conductivity and shifts the work function of the graphene electrode, resulting in improved overall PCE performance of the OPV devices. This work brings us one step further toward the future use of graphene transparent electrodes as a replacement for ITO.

  5. Functional Biomass Carbons with Hierarchical Porous Structure for Supercapacitor Electrode Materials

    International Nuclear Information System (INIS)

    Chen, Hao; Liu, Duo; Shen, Zhehong; Bao, Binfu; Zhao, Shuyan; Wu, Limin

    2015-01-01

    Highlights: • We successfully prepared bamboo-derived porous carbon with B and N co-doping. • This novel carbon exhibits significantly enhanced specific capacitance and energy density. • The highest specific capacitance exceeds those of most similar carbon materials. • Asymmetric supercapacitor based on this carbon shows satisfactory capacitive performance. - Abstract: This paper presents nitrogen and boron co-doped KOH-activated bamboo-derived carbon as a porous biomass carbon with utility as a supercapacitor electrode material. Owing to the high electrochemical activity promoted by the hierarchical porous structure and further endowed by boron and nitrogen co-doping, electrodes based on the as-obtained material exhibit significantly enhanced specific capacitance and energy density relative to those based on most similar materials. An asymmetric supercapacitor based on this novel carbon material demonstrated satisfactory energy density and electrochemical cycling stability.

  6. Calibrated work function mapping by Kelvin probe force microscopy

    Science.gov (United States)

    Fernández Garrillo, Pablo A.; Grévin, Benjamin; Chevalier, Nicolas; Borowik, Łukasz

    2018-04-01

    We propose and demonstrate the implementation of an alternative work function tip calibration procedure for Kelvin probe force microscopy under ultrahigh vacuum, using monocrystalline metallic materials with known crystallographic orientation as reference samples, instead of the often used highly oriented pyrolytic graphite calibration sample. The implementation of this protocol allows the acquisition of absolute and reproducible work function values, with an improved uncertainty with respect to unprepared highly oriented pyrolytic graphite-based protocols. The developed protocol allows the local investigation of absolute work function values over nanostructured samples and can be implemented in electronic structures and devices characterization as demonstrated over a nanostructured semiconductor sample presenting Al0.7Ga0.3As and GaAs layers with variable thickness. Additionally, using our protocol we find that the work function of annealed highly oriented pyrolytic graphite is equal to 4.6 ± 0.03 eV.

  7. Polymer-Derived Ceramic Functionalized MoS2 Composite Paper as a Stable Lithium-Ion Battery Electrode

    Science.gov (United States)

    David, L.; Bhandavat, R.; Barrera, U.; Singh, G.

    2015-04-01

    A facile process is demonstrated for the synthesis of layered SiCN-MoS2 structure via pyrolysis of polysilazane functionalized MoS2 flakes. The layered morphology and polymer to ceramic transformation on MoS2 surfaces was confirmed by use of electron microscopy and spectroscopic techniques. Tested as thick film electrode in a Li-ion battery half-cell, SiCN-MoS2 showed the classical three-stage reaction with improved cycling stability and capacity retention than neat MoS2. Contribution of conversion reaction of Li/MoS2 system on overall capacity was marginally affected by the presence of SiCN while Li-irreversibility arising from electrolyte decomposition was greatly suppressed. This is understood as one of the reasons for decreased first cycle loss and increased capacity retention. SiCN-MoS2 in the form of self-supporting paper electrode (at 6 mg.cm-2) exhibited even better performance, regaining initial charge capacity of approximately 530 mAh.g-1 when the current density returned to 100 mA.g-1 after continuous cycling at 2400 mA.g-1 (192 mAh.g-1). MoS2 cycled electrode showed mud-cracks and film delamination whereas SiCN-MoS2 electrodes were intact and covered with a uniform solid electrolyte interphase coating. Taken together, our results suggest that molecular level interfacing with precursor-derived SiCN is an effective strategy for suppressing the metal-sulfide/electrolyte degradation reaction at low discharge potentials.

  8. Insights into the Influence of Work Functions of Cathodes on Efficiencies of Perovskite Solar Cells.

    Science.gov (United States)

    Yue, Shizhong; Lu, Shudi; Ren, Kuankuan; Liu, Kong; Azam, Muhammad; Cao, Dawei; Wang, Zhijie; Lei, Yong; Qu, Shengchun; Wang, Zhanguo

    2017-05-01

    Though various efforts on modification of electrodes are still undertaken to improve the efficiency of perovskite solar cells, attributing to the large scope of these methods, it is of significance to unveil the working principle systematically. Herein, inverted perovskite solar cells based on indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH 3 NH 3 PbI 3 /phenyl-C61-butyric acid methyl ester (PC 61 BM)/buffer metal/Al are constructed. Through the choice of different buffer metals to tune work function of the cathode, the contact nature of the active layer with the cathode could be manipulated well. In comparison with the device using Au/Al as the electrode that shows an unfavorable band bending for conducting the excited electrons to the cathode, the one with Ca/Al presents a dramatically improved efficiency over 17.1%, ascribed to the favorable band bending at the interface of the cathode with the active layer. Details for tuning the band bending and the corresponding charge transfer mechanism are given in a systematic manner. Thus, a general guideline for constructing perovskite photovoltaic devices efficiently is provided. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Statistical models of a gas diffusion electrode: II. Current resistent

    Energy Technology Data Exchange (ETDEWEB)

    Proksch, D B; Winsel, O W

    1965-07-01

    The authors describe an apparatus for measuring the flow resistance of gas diffusion electrodes which is a mechanical analog of the Wheatstone bridge for measuring electric resistance. The flow resistance of a circular DSK electrode sheet, consisting of two covering layers and a working layer between them, was measured as a function of the gas pressure. While the pressure first was increased and then decreased, a hysteresis occurred, which is discussed and explained by a statistical model of a porous electrode.

  10. Reduced work function of graphene by metal adatoms

    Energy Technology Data Exchange (ETDEWEB)

    Legesse, Merid; Mellouhi, Fedwa El; Bentria, El Tayeb; Madjet, Mohamed E. [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Doha (Qatar); Fisher, Timothy S. [School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907 (United States); Kais, Sabre [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Doha (Qatar); Department of Chemistry and Physics, Purdue University, West Lafayette, IN 46323 (United States); College of Science and Engineering, Hamad Bin Khalifa University, Doha (Qatar); Alharbi, Fahhad H., E-mail: falharbi@qf.org.qa [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Doha (Qatar); College of Science and Engineering, Hamad Bin Khalifa University, Doha (Qatar)

    2017-02-01

    Highlights: • Using DFT, the maximum reduction of graphene workfunction is investigated. This is important for many applications. • The calculations show that the adatoms prefer to relax at hollow sites. • The transfer of electrons from the adatoms to graphene shifts up the Fermi level. So, graphene becomes metallic. • For those dopants that have been used experimentally, the calculations agree with the experimental data. • We found that 8% doping by Cs reduces the work function to 2.05 eV. - Abstract: In this paper, the work function of graphene doped by different metal adatoms and at different concentrations is investigated. Density functional theory is used to maximize the reduction of the work function. In general, the work function drops significantly before reaching saturation. For example in the case of Cs doping, the work function saturates at 2.05 eV with a modest 8% doping. The adsorption of different concentrations on metal adatoms on graphene is also studied. Our calculations show that the adatoms prefer to relax at hollow sites. The transfer of electron from metallic dopants to the graphene for all the studied systems shifts the Fermi energy levels above the Dirac-point and the doped graphenes become metallic. The value of Fermi energy shifts depends on the type of metallic dopants and its concentrations. A detail analysis of the electronic structure in terms of band structure and density of states, absorption energy, and charge transfer for each adatom-graphene system is presented.

  11. Reduced work function of graphene by metal adatoms

    International Nuclear Information System (INIS)

    Legesse, Merid; Mellouhi, Fedwa El; Bentria, El Tayeb; Madjet, Mohamed E.; Fisher, Timothy S.; Kais, Sabre; Alharbi, Fahhad H.

    2017-01-01

    Highlights: • Using DFT, the maximum reduction of graphene workfunction is investigated. This is important for many applications. • The calculations show that the adatoms prefer to relax at hollow sites. • The transfer of electrons from the adatoms to graphene shifts up the Fermi level. So, graphene becomes metallic. • For those dopants that have been used experimentally, the calculations agree with the experimental data. • We found that 8% doping by Cs reduces the work function to 2.05 eV. - Abstract: In this paper, the work function of graphene doped by different metal adatoms and at different concentrations is investigated. Density functional theory is used to maximize the reduction of the work function. In general, the work function drops significantly before reaching saturation. For example in the case of Cs doping, the work function saturates at 2.05 eV with a modest 8% doping. The adsorption of different concentrations on metal adatoms on graphene is also studied. Our calculations show that the adatoms prefer to relax at hollow sites. The transfer of electron from metallic dopants to the graphene for all the studied systems shifts the Fermi energy levels above the Dirac-point and the doped graphenes become metallic. The value of Fermi energy shifts depends on the type of metallic dopants and its concentrations. A detail analysis of the electronic structure in terms of band structure and density of states, absorption energy, and charge transfer for each adatom-graphene system is presented.

  12. Emerging Novel Metal Electrodes for Photovoltaic Applications.

    Science.gov (United States)

    Lu, Haifei; Ren, Xingang; Ouyang, Dan; Choy, Wallace C H

    2018-04-01

    Emerging novel metal electrodes not only serve as the collector of free charge carriers, but also function as light trapping designs in photovoltaics. As a potential alternative to commercial indium tin oxide, transparent electrodes composed of metal nanowire, metal mesh, and ultrathin metal film are intensively investigated and developed for achieving high optical transmittance and electrical conductivity. Moreover, light trapping designs via patterning of the back thick metal electrode into different nanostructures, which can deliver a considerable efficiency improvement of photovoltaic devices, contribute by the plasmon-enhanced light-mattering interactions. Therefore, here the recent works of metal-based transparent electrodes and patterned back electrodes in photovoltaics are reviewed, which may push the future development of this exciting field. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Electrochemical detection of acetaminophen on the functionalized MWCNTs modified electrode using layer-by-layer technique

    International Nuclear Information System (INIS)

    Manjunatha, Revanasiddappa; Nagaraju, Dodahalli Hanumantharayudu; Suresh, Gurukar Shivappa; Melo, Jose Savio; D'Souza, Stanislaus F.; Venkatesha, Thimmappa Venkatarangaiah

    2011-01-01

    A selective electrochemical method is fabricated via layer-by-layer (LBL) method using both positively and negatively charged multi walled carbon nanotubes (MWCNTs) on poly (diallyldimetheylammonium chloride) (PDDA)/poly styrene sulfonate (PSS) modified graphite electrode, for the determination of acetaminophen (ACT) in the presence of dopamine (DA) and high concentration of ascorbic acid (AA). The modified electrode was characterized by cyclic voltammetry (CV) electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Experimental conditions such as pH, accumulation potential and time, effect of potential sweep rates and interferents were studied. In CV well defined peaks for AA, ACT and DA are obtained at 24, 186 and 374 mV, respectively. The separations of peaks were 210, 188 and 398 mV between AA and DA, DA and ACT and AA and ACT, respectively. The diffusion coefficient was calculated by chronocoulometric. Chronoamperometric studies showed the linear relationship between oxidation peak current and concentration of ACT in the range 25-400 μM (R = 0.9991). The detection limit was 5 x 10 -7 mol/L. The proposed method gave satisfactory results in the determination of ACT in pharmaceutical and human serum samples.

  14. Functional MR imaging of working memory in the human brain

    International Nuclear Information System (INIS)

    Na, Dong Gyu; Ryu, Jae Wook; Byun, Hong Sik; Lee, Eun Jeong; Chung, Woo In; Cho, Jae Min; Han, Boo Kyung; Choi, Dae Seob

    2000-01-01

    In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory

  15. Functional MR imaging of working memory in the human brain

    Energy Technology Data Exchange (ETDEWEB)

    Na, Dong Gyu; Ryu, Jae Wook; Byun, Hong Sik; Lee, Eun Jeong; Chung, Woo In; Cho, Jae Min; Han, Boo Kyung [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Choi, Dae Seob [Dongguk University College of Medicine, Seoul (Korea, Republic of)

    2000-03-01

    In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.

  16. The work ability index and functional capacity among older workers

    Directory of Open Access Journals (Sweden)

    Rosimeire S. Padula

    2013-08-01

    Full Text Available BACKGROUND: Decreases in functional ability due to aging can impair work capacity and productivity among older workers. OBJECTIVE: This study compares the sociodemographics, health conditions, and physical functioning abilities of young and old workers as well as correlates of physical functioning capacity with the work ability index (WAI. METHOD: This exploratory, cross-sectional study examined employees of a higher education institution (HEI and those of a metallurgical industry. Older workers (50 years old or above were matched for gender and occupation type with younger workers (less than 50 years old. The following evaluations were applied: the multidimensional assessment questionnaire (which included sociodemographic, clinical, health perception, and physical health indices, the WAI, and a battery of physical functional tests. RESULTS: Diseases and regularly used medications were more common among the group of aging workers. The WAI did not differ between groups (p=0.237. Both groups showed similar physical functional capacity performances with regard to walking speed, muscle strength, and lower limb physical functioning. Aging workers showed a poorer performance on a test of right-leg support (p=0.004. The WAI was moderately correlated with the sit-to-stand test among older female workers (r=0.573, p=0.051. CONCLUSIONS: Unfavorable general health conditions did not affect the assessment of work ability or most of the tests of physical functional capacity in the aging group.

  17. The electronic work function of the different faces of tungsten

    International Nuclear Information System (INIS)

    Modinos, A.

    1978-01-01

    A semi-empirical theory of the electronic work function of the different faces of tungsten is presented. All the parameters entering the theory, except one, are estimated independently. The one adjustable parameter relates to the isotropic contribution to the work function, and, can, in principle, be determined from a self-consistent calculation of the band-structure of the energy levels in the bulk of the metal. The calculated values for the work function are in reasonably good agreement with available experimental data for practically all of the crystallographic planes with the exception of the (100) plane. For the latter, the calculated value is 0.3 eV above the experimental value. It is suggested that a negative contribution to the surface dipole potential from surface states, that exist on this plane, may be the reason of this discrepancy. (Auth.)

  18. Recommended values of clean metal surface work functions

    International Nuclear Information System (INIS)

    Derry, Gregory N.; Kern, Megan E.; Worth, Eli H.

    2015-01-01

    A critical review of the experimental literature for measurements of the work functions of clean metal surfaces of single-crystals is presented. The tables presented include all results found for low-index crystal faces except cases that were known to be contaminated surfaces. These results are used to construct a recommended value of the work function for each surface examined, along with an uncertainty estimate for that value. The uncertainties are based in part on the error distribution for all measured work functions in the literature, which is included here. The metals included in this review are silver (Ag), aluminum (Al), gold (Au), copper (Cu), iron (Fe), iridium (Ir), molybdenum (Mo), niobium (Nb), nickel (Ni), palladium (Pd), platinum (Pt), rhodium (Rh), ruthenium (Ru), tantalum (Ta), and tungsten (W)

  19. Recommended values of clean metal surface work functions

    Energy Technology Data Exchange (ETDEWEB)

    Derry, Gregory N., E-mail: gderry@loyola.edu; Kern, Megan E.; Worth, Eli H. [Department of Physics, Loyola University Maryland, 4501 N. Charles St., Baltimore, Maryland 21210 (United States)

    2015-11-15

    A critical review of the experimental literature for measurements of the work functions of clean metal surfaces of single-crystals is presented. The tables presented include all results found for low-index crystal faces except cases that were known to be contaminated surfaces. These results are used to construct a recommended value of the work function for each surface examined, along with an uncertainty estimate for that value. The uncertainties are based in part on the error distribution for all measured work functions in the literature, which is included here. The metals included in this review are silver (Ag), aluminum (Al), gold (Au), copper (Cu), iron (Fe), iridium (Ir), molybdenum (Mo), niobium (Nb), nickel (Ni), palladium (Pd), platinum (Pt), rhodium (Rh), ruthenium (Ru), tantalum (Ta), and tungsten (W)

  20. Work functions and surface charges at metallic facet edges

    International Nuclear Information System (INIS)

    Fall, C.J.; Binggeli, N.; Baldereschi, A.

    2002-04-01

    The electronic charge densities and work functions at sharp metallic facet edges are determined from ab initio calculations, combined with macroscopic averaging techniques. In particular, we examine how two different work functions coexist at close range near edges between inequivalent facets. The surface ionic relaxation at facet edges is shown to influence appreciably the local electrostatic potential in the vacuum. Various edges between Al(100) and Al(111) facets are studied, as well as between Na(110) facets. We also develop a model of electronic surface dipoles, which accounts for the surface charge transfer between inequivalent facets, and which allows us to predict the influence of the shape and size of a macroscopic crystal on its work functions. (author)

  1. Hearing aid noise suppression and working memory function

    OpenAIRE

    Fischer, Rosa-Linde; Neher, Tobias; Wagener, Kirsten C.

    2017-01-01

    OBJECTIVE: Research findings concerning the relation between benefit from hearing aid (HA) noise suppression and working memory function are inconsistent. The current study thus investigated the effects of three noise suppression algorithms on auditory working memory and the relation with reading span.DESIGN: Using a computer simulation of bilaterally fitted HAs, four settings were tested: (1) unprocessed, (2) directional microphones, (3) single-channel noise reduction and (4) binaural cohere...

  2. Method for finding the distribution function of the ions formed in an electrode sheath in a plasma

    International Nuclear Information System (INIS)

    Chumenkov, V.

    1981-01-01

    A steady-state one-dimensional kinetic equation is studied for the ions formed in an electrode sheath in a discharge in a transverse magnetic field and also in the ionization--acceleration zone of Hall accelerators. Only single ionization of atoms by electron impact is considered in the collision term on the right side of the equation. The variables which appear on the right side are grouped into an expression which is a measure of the ion energy distribution. The problem is solved through the use of an empirical expression for the integrated ion energy distribution. This approach for finding the ion distribution function makes it a comparatively simple matter to trace the evolution of the distribution function due to changes in the external parameters (the magnetic field, the discharge voltage, and the pressure) or in the geometric characteristics of the discharge apparatus

  3. 3D Graphene Functionalized by Covalent Organic Framework Thin Film as Capacitive Electrode in Alkaline Media.

    Science.gov (United States)

    Zha, Zeqi; Xu, Lirong; Wang, Zhikui; Li, Xiaoguang; Pan, Qinmin; Hu, Pingan; Lei, Shengbin

    2015-08-19

    To harness the electroactivity of anthraquinone as an electrode material, a great recent effort have been invested to composite anthraquinone with carbon materials to improve the conductivity. Here we report on a noncovalent way to modify three-dimensional graphene with anthraquinone moieties through on-surface synthesis of two-dimensional covalent organic frameworks. We incorporate 2,6-diamino-anthraquinone moieties into COF through Schiff-base reaction with benzene-1,3,5-tricarbaldehyde. The synthesized COF -graphene composite exhibits large specific capacitance of 31.7 mF/cm(2). Long-term galvanostatic charge/discharge cycling experiments revealed a decrease of capacitance, which was attributed to the loss of COF materials and electrostatic repulsion accumulated during charge-discharge circles which result in the poor electrical conductivity between 2D COF layers.

  4. Bike Desks in the Office: Physical Health, Cognitive Function, Work Engagement, and Work Performance.

    Science.gov (United States)

    Torbeyns, Tine; de Geus, Bas; Bailey, Stephen; De Pauw, Kevin; Decroix, Lieselot; Van Cutsem, Jeroen; Meeusen, Romain

    2016-12-01

    The aim of this study was to examine the longitudinal effect of implementing bike desks in an office setting on physical health, cognition, and work parameters. Physical health, cognitive function, work engagement, and work performance measured before (T0) and after (T2) the intervention period were compared between office workers who used the bike desk (IG, n = 22) and those who did not (CG, n = 16). The IG cycled approximately 98 minutes/week. The IG showed a significantly lower fat percentage and a trend toward a higher work engagement at T2 relative to T0, while this was not different for the CG. No effects on other parameters of health, cognition, or work performance were found. Providing bike desks in the office positively influences employees' fat percentage and could positively influence work engagement without compromising work performance.

  5. Hearing aid noise suppression and working memory function

    DEFF Research Database (Denmark)

    Neher, Tobias; Wagener, Kirsten C.; Fischer, Rosa-Linde

    2018-01-01

    OBJECTIVE: Research findings concerning the relation between benefit from hearing aid (HA) noise suppression and working memory function are inconsistent. The current study thus investigated the effects of three noise suppression algorithms on auditory working memory and the relation with reading......-to-noise ratio (SNR) improvement. Auditory working memory was assessed at +6 dB SNR using listening span and N-back paradigms. STUDY SAMPLE: Twenty experienced HA users ages 55-80 with large differences in reading span. RESULTS: For the listening span measurements, there was an influence of HA setting....... CONCLUSIONS: HA noise suppression may affect the recognition and recall of speech at positive SNRs, irrespective of individual reading span. Future work should improve the reliability of the auditory working memory measurements....

  6. Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2015-07-01

    Full Text Available Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes.

  7. Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation

    Science.gov (United States)

    Zhou, Hui; Lu, Yi; Chen, Wanzhen; Wu, Zhen; Zou, Haiqing; Krundel, Ludovic; Li, Guanglin

    2015-01-01

    Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes. PMID:26193273

  8. The Work Function Associated with Ultra-relativistic Electron ...

    Indian Academy of Sciences (India)

    The energy required to liberate an electron in the Fermi level is the work function and is ... potential difference will be developed across a thin gap, called the polar gap. This ... The emission of electrons from the polar region of neutron stars is.

  9. Functional Requirements for an Electronic Work Package System

    Energy Technology Data Exchange (ETDEWEB)

    Oxstrand, Johanna H. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-12-01

    This document provides a set of high level functional requirements for a generic electronic work package (eWP) system. The requirements have been identified by the U.S. nuclear industry as a part of the Nuclear Electronic Work Packages - Enterprise Requirements (NEWPER) initiative. The functional requirements are mainly applied to eWP system supporting Basic and Moderate types of smart documents, i.e., documents that have fields for recording input such as text, dates, numbers, and equipment status, and documents which incorporate additional functionalities such as form field data “type“ validation (e.g. date, text, number, and signature) of data entered and/or self-populate basic document information (usually from existing host application meta data) on the form when the user first opens it. All the requirements are categorized by the roles; Planner, Supervisor, Craft, Work Package Approval Reviewer, Operations, Scheduling/Work Control, and Supporting Functions. The categories Statistics, Records, Information Technology are also included used to group the requirements. All requirements are presented in Section 2 through Section 11. Examples of more detailed requirements are provided for the majority of high level requirements. These examples are meant as an inspiration to be used as each utility goes through the process of identifying their specific requirements. The report’s table of contents provides a summary of the high level requirements.

  10. Engineering the work function of buckled boron α-sheet by lithium adsorption: a first-principles investigation.

    Science.gov (United States)

    Zheng, Bing; Yu, Hai-tao; Xie, Ying; Lian, Yong-fu

    2014-11-26

    First-principles density functional theory calculations were performed to study the effect of Li adsorption on the structural and electronic properties, particularly the work function, of boron α-sheet. The calculated binding energies indicated that boron α-sheet could be well stabilized by the adsorption of Li atoms. Furthermore, the work functions of Li-adsorbed boron α-sheets were observed to decrease drastically with increasing Li coverage. The work functions are lower than that of Mg and even, for some of them, lower than that of Ca, indicating a considerable potential application of Li-adsorbed boron α-sheets as field-emission and electrode materials. Based on the calculated geometric and electronic structures, we discuss in details some possible aspects affecting the work function. The Li coverage dependence of the work functions of Li-adsorbed boron α-sheets was further confirmed by electrostatic potential analyses. The relationship between the work function variation and the Fermi and vacuum energy level shifts was also discussed, and we observed that the variation of the work function is primarily associated with the shift of the Fermi energy level. It is the surface dipole formed by the interaction between adatoms and substrate that should be responsible for the observed variation of the work function, whereas the increasing negative charge and rumpling for boron α-sheet only play minor roles. Additionally, the effect of Li adatoms on the work function of boron α-sheet was confirmed to be much stronger than that of graphene or a graphene double layer.

  11. Working memory overload: fronto-limbic interactions and effects on subsequent working memory function.

    Science.gov (United States)

    Yun, Richard J; Krystal, John H; Mathalon, Daniel H

    2010-03-01

    The human working memory system provides an experimentally useful model for examination of neural overload effects on subsequent functioning of the overloaded system. This study employed functional magnetic resonance imaging in conjunction with a parametric working memory task to characterize the behavioral and neural effects of cognitive overload on subsequent cognitive performance, with particular attention to cognitive-limbic interactions. Overloading the working memory system was associated with varying degrees of subsequent decline in performance accuracy and reduced activation of brain regions central to both task performance and suppression of negative affect. The degree of performance decline was independently predicted by three separate factors operating during the overload condition: the degree of task failure, the degree of amygdala activation, and the degree of inverse coupling between the amygdala and dorsolateral prefrontal cortex. These findings suggest that vulnerability to overload effects in cognitive functioning may be mediated by reduced amygdala suppression and subsequent amygdala-prefrontal interaction.

  12. Lung function studies before and after a work shift

    Energy Technology Data Exchange (ETDEWEB)

    Love, R G

    1983-05-01

    The lung function of 23 underground coal workers and eight surface workers at a Scottish colliery was measured immediately before and after a work shift. Changes in lung function were assessed in relation to the measured respirable dust exposure and the time of day in which the shift was worked. Large, and statistically significant, decrements of lung function during the shift were found in night-shift workers compared with workers on other shifts. Measurements derived from the forced expiratory manoeuvre, particularly FEV1, Vmax50, and Vmax25, after three vital capacity breaths of an 80% He/20% O2 mixture, showed large reductions in night-shift men, smaller reductions in afternoon-shift men, and small increases or decreases in morning-shift underground and surface workers. Within-shift changes for other tests, such as closing volume, N2 index, and volume of isoflow, did not differ significantly between shifts. No significant relationship was found between dust exposure and functional changes during a shift for any test. Lung function changes in a control group of 25 female workers not exposed to dust (hospital nurses) did not show the same large variations between day and night shifts. Examination of a further control group of 16 office workers did not show any difference in diurnal changes between smokers and non-smokers. It is concluded that these coal miners, even on permanent shift patterns, had widely different changes in their lung function cycle depending on which shift they were working. These changes did not appear to be related to dust exposure or cigarette smoking and were not consistent with other biological adaptations known to result from regular night-shift working.

  13. A survey of reference electrodes for high temperature waters; Oeversikt av referenselektroder i hoegtemperaturvatten

    Energy Technology Data Exchange (ETDEWEB)

    Molander, A.; Eriksson, Sture; Pein, K. [Studsvik Nuclear, Nykoeping (Sweden)

    2000-11-01

    In nuclear power plants, corrosion potential measurements are used to follow the conditions for different corrosion types in reactor systems, particularly IGSCC in BWRs. The goal of this work has been to give a survey of reference electrodes for high temperature water, both those that are used for nuclear environments and those that are judged to possible future development. The reference electrodes that are used today in nuclear power plants for corrosion potential measurements are of three types. Silver chloride electrodes, membrane electrodes and platinum electrodes (hydrogen electrodes). The principals for their function is described as well as the conversion of measured potentials to the SHE scale (Standard Hydrogen Electrode). Silver chloride electrodes consist of an inner reference system of silver chloride in equilibrium with a chloride solution. The silver chloride electrode is the most common reference electrode and can be used in several different systems. Platinum electrodes are usually more robust and are particularly suitable to use in BWR environment to follow the hydrogen dosage, but have limitations at low and no hydrogen dosage. Ceramic membrane electrodes can be with different types of internal reference system. They were originally developed for pH measurements in high temperature water. If pH is constant, the membrane electrode can be used as reference electrode. A survey of ceramic reference electrodes for high temperature water is given. A ceramic membrane of the type used works as an oxygen conductor, so the potential and pH in surrounding medium is in equilibrium with the internal reference system. A survey of the lately development of electrodes is presented in order to explain why the different types of electrodes are developed as well as to give a background to the possibilities and limitations with the different electrodes. Possibilities of future development of electrodes are also given. For measurements at low or no hydrogen dosage

  14. Functional MR imaging of working memory before neurosurgery

    International Nuclear Information System (INIS)

    Wunderlich, A.P.; Groen, G.; Braun, V.

    2007-01-01

    Information concerning the tissue adjacent to a brain tumour is crucial for planning and performing a neurosurgical intervention. In this study, we evaluated the usefulness of functional imaging of working memory in terms of working memory preservation. Working memory performance of 14 patients with prefrontal tumours was tested preoperatively by means of a standardized neuropsychological test battery. Also, functional magnetic resonance imaging (fMRI) using a so-called two-back paradigm was performed to visualize brain areas related to that task. Working memory areas were reliably detected in all patients. Surgery was then planned on the basis of this information, and the data were used for intra-operative cranial neuronavigation. Three to twelve months after surgery, patients were tested again with the test battery in order to detect possible changes in working memory performance. In 13 cases the memory performance was unchanged, only one female patient had a slight impairment of working memory compared to the pre-operative status. (orig.)

  15. Flexible transparent electrode

    Science.gov (United States)

    Demiryont, Hulya; Shannon, Kenneth C., III; Moorehead, David; Bratcher, Matthew

    2011-06-01

    This paper presents the properties of the EclipseTECTM transparent conductor. EclipseTECTM is a room temperature deposited nanostructured thin film coating system comprised of metal-oxide semiconductor elements. The system possesses metal-like conductivity and glass-like transparency in the visible region. These highly conductive TEC films exhibit high shielding efficiency (35dB at 1 to 100GHz). EclipseTECTM can be deposited on rigid or flexible substrates. For example, EclipseTECTM deposited on polyethylene terephthalate (PET) is extremely flexible that can be rolled around a 9mm diameter cylinder with little or no reduction in electrical conductivity and that can assume pre-extension states after an applied stress is relieved. The TEC is colorless and has been tailored to have high visible transmittance which matches the eye sensitivity curve and allows the viewing of true background colors through the coating. EclipseTECTM is flexible, durable and can be tailored at the interface for applications such as electron- or hole-injecting OLED electrodes as well as electrodes in flexible displays. Tunable work function and optical design flexibility also make EclipseTECTM well-suited as a candidate for grid electrode replacement in next-generation photovoltaic cells.

  16. A short executive function training program improves preschoolers’ working memory

    Directory of Open Access Journals (Sweden)

    Emma eBlakey

    2015-11-01

    Full Text Available Cognitive training has been shown to improve executive functions in middle childhood and adulthood. However, fewer studies have targeted the preschool years – a time when executive functions undergo rapid development. The present study tested the effects of a short four session executive function training program in 54 four-year-olds. The training group significantly improved their working memory from pre-training relative to an active control group. Notably, this effect extended to a task sharing few surface features with the trained tasks, and continued to be apparent three months later. In addition, the benefits of training extended to a measure of mathematical reasoning three months later, indicating that training executive functions during the preschool years has the potential to convey benefits that are both long-lasting and wide-ranging.

  17. Chronic implantation of cuff electrodes on the pelvic nerve in rats is well tolerated and does not compromise afferent or efferent fibre functionality

    Science.gov (United States)

    Crook, J. J.; Brouillard, C. B. J.; Irazoqui, P. P.; Lovick, T. A.

    2018-04-01

    Objective. Neuromodulation of autonomic nerve activity to regulate physiological processes is an emerging field. Vagal stimulation has received most attention whereas the potential of modulate visceral function by targeting autonomic nerves within the abdominal cavity remains under-exploited. Surgery to locate intra-abdominal targets is inherently more stressful than for peripheral nerves. Electrode leads risk becoming entrapped by intestines and loss of functionality in the nerve-target organ connection could result from electrode migration or twisting. Since nociceptor afferents are intermingled with similar-sized visceral autonomic fibres, stimulation may induce pain. In anaesthetised rats high frequency stimulation of the pelvic nerve can suppress urinary voiding but it is not known how conscious animals would react to this procedure. Our objective therefore was to determine how rats tolerated chronic implantation of cuff electrodes on the pelvic nerve, whether nerve stimulation would be aversive and whether nerve-bladder functionality would be compromised. Approach. We carried out a preliminary de-risking study to investigate how conscious rats tolerated chronic implantation of electrodes on the pelvic nerve, their responsiveness to intermittent high frequency stimulation and whether functionality of the nerve-bladder connection became compromised. Main results. Implantation of cuff electrodes was well-tolerated. The normal diurnal pattern of urinary voiding was not disrupted. Pelvic nerve stimulation (up to 4 mA, 3 kHz) for 30 min periods evoked mild alerting at stimulus onset but no signs of pain. Stimulation evoked a modest (nerve temperature but the functional integrity of the nerve-bladder connection, reflected by contraction of the detrusor muscle in response to 10 Hz nerve stimulation, was not compromised. Significance. Chronic implantation of cuff electrodes on the pelvic nerve was found to be a well-tolerated procedure in rats and high frequency

  18. Carbon Paste Electrode Modified with Carbamoylphosphonic Acid Functionalized Mesoporous Silica: A New Mercury-Free Sensor for Uranium Detection

    International Nuclear Information System (INIS)

    Yantasee, Wassana; Lin, Yuehe; Fryxell, Glen E.; Wang, Zheming

    2004-01-01

    This study reports a new approach for developing a uranium (U(VI)) electrochemical sensor that is mercury-free, solid-state, and has less chance for ligand depletion than existing sensors. A carbon-paste electrode modified with carbamoylphosphonic acid self-assembled monolayer on mesoporous silica was developed for uranium detection based on an adsorptive square-wave stripping voltammetry technique. Voltammetric responses for U(VI) detection are reported as a function of pH, preconcentration time, and aqueous phase U(VI) concentration. The uranium detection limit is 25 ppb after 5 minutes preconcentration and improved to 1 ppb after 20 minutes preconcentration. The relative standard deviations are normally less than 5%

  19. Electroanalysis of formetanate hydrochloride by a cobalt phthalocyanine functionalized multiwalled carbon nanotubes modified electrode: characterization and application in fruits

    International Nuclear Information System (INIS)

    Ribeiro, Francisco Wirley Paulino; Souza Lucas, Francisco Willian de; Mascaro, Lucia H.; Morais, Simone; Naftali da Silva Casciano, Paulo; Lima-Neto, Pedro de; Correia, Adriana N.

    2016-01-01

    Highlights: • A Co-phthalocyanine functionalized MWCNT modified carbon electrode was developed. • Formetanate (FMT) electroanalytical behavior is consistent with an ECE mechanism. • CoPc-fMWCNT/GCE exhibited good analytical performance to quantify FMT. • CoPc-fMWCNT/GCE was successfully applied to fruits (recoveries ≥ 94.2%). - Abstract: This study characterizes the electroanalytical behavior of the carbamate pesticide formetanate hydrochloride (FMT) at a cobalt phthalocyanine (CoPc) functionalized multiwalled carbon nanotubes (fMWCNT) modified glassy carbon electrode (CoPc-fMWCNT/GCE). Nafion ® was used to improve solubility and dispersibility of fMWCNT. The construction of the developed electrode was characterized by high-resolution field-emission gun scanning electron microscopy, Raman spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. FMT exhibited a behavior consistent with a three-step reaction of the electrochemical-chemical-electrochemical mechanistic type at CoPc-fMWCNT/GCE (three anodic peaks at 0.26, 0.55 and 1.2 V, and two cathodic peaks at 0.35 and 0.50 V vs. Ag/AgCl/3 M KCl). Highly reproducible and well-defined peaks were obtained at the optimum experimental conditions (Britton-Robinson buffer at pH 5.0, accumulation potential 1.55 V, accumulation time 5 s, frequency 100 s −1 , amplitude 30 mV, and scan increment 3 mV). Peak currents were found to be proportional to the FMT concentrations in the range of 9.80 × 10 −8 to 3.92 × 10 −6 mol dm −3 with a detection limit (LOD) of 9.7 × 10 −8 mol dm −3 . The modification of GCE with CoPc-fMWCNT enhanced the electrocatalytic activity and provided high sensitivity (3.51 A mol −1 dm 3 ). The developed electroanalytical methodology was successfully applied to FMT residue analysis in mango and grape samples with recoveries in the range of 94.2 ± 4.5 to 105.7 ± 1.8%. The proposed electroanalytical approach represents a reliable, sensitive and environmental

  20. Simultaneous detection of metronidazole and chloramphenicol by differential pulse stripping voltammetry using a silver nanoparticles/sulfonate functionalized graphene modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Zhai, Haiyun; Liang, Zhixian; Chen, Zuanguang; Wang, Haihang; Liu, Zhenping; Su, Zihao; Zhou, Qing

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: • A novel and reliable AgNPs/SF-GR modified glassy carbon electrode was constructed and characterized. • The AgNPs/SF-GR/GCE was successfully applied in the shrimp for simultaneous determination of MTZ and CAP. • Under optimized conditions, common substances such as UA, AA, DA and ion did not interfered in the electrode performance. • The modified electrode exhibited considerable sensitivity, stability and reproducibility. • This fabricated electrode achieved a satisfactory level compared with other electrodes toward MTZ and CAP. -- Abstract: A novel silver nanoparticles/sulfonated functionalized graphene modified glassy carbon electrode (AgNPs/SF-GR/GCE) was fabricated to determine chloramphenicol and metronidazole simultaneously. Taking advantage of sulfonic group, AgNPs were successfully electrodeposited on functionalized GR immobilized on the surface of a GCE. Scanning electron microscopy and energy spectrum analysis results confirmed that AgNPs were deposited on the functionalized GR film. Compared to the bare GCE or the pristine SF-GR modified electrode, AgNPs/SF-GR/GCE exhibited excellent electroreduction towards chloramphenicol and metronidazole. In addition, the two antibacterial drugs were separated completely in 0.10 M citric acid-sodium citrate buffer (pH 4.0) by differential pulse stripping voltammetry under optimum conditions. The cathodic current was linearly related with 0.02∼20.0 μM chloramphenicol and 0.10∼20.0 μM metronidazole, with the detection limits of 0.01 μM and 0.05 μM respectively. Furthermore, AgNPs/SF-GR/GCE was applied to the simultaneous determination of chloramphenicol and metronidazole in an aquatic product

  1. Microwave-assisted preparation of carbon nanofiber-functionalized graphite felts as electrodes for polymer-based redox-flow batteries

    Science.gov (United States)

    Schwenke, A. M.; Janoschka, T.; Stolze, C.; Martin, N.; Hoeppener, S.; Schubert, U. S.

    2016-12-01

    A simple and fast microwave-assisted protocol to functionalize commercially available graphite felts (GFs) with carbon nanofibers (CNFs) for the application as electrode materials in redox-flow batteries (RFB) is demonstrated. As catalyst for the CNF synthesis nickel acetate is applied and ethanol serves as the carbon source. By the in-situ growth of CNFs, the active surface of the electrodes is increased by a factor of 50, which is determined by the electrochemical double layer capacities of the obtained materials. Furthermore, the morphology of the CNF-coating is investigated by scanning electron microscopy. Subsequently, the functionalized electrodes are applied in a polymer-based redox-flow battery (pRFB) using a TEMPO- and a viologen polymer as active materials. Due to the increased surface area as compared to an untreated graphite felt electrode, the current rating is improved by about 45% at 80 mA cm-2 and, furthermore, a decrease in overpotentials is observed. Thus, using this microwave-assisted synthesis approach, CNF-functionalized composite electrodes are prepared with a very simple protocol suitable for real life applications and an improvement of the overall performance of the polymer-based redox-flow battery is demonstrated.

  2. Career Development and Personal Functioning Differences between Work-Bound and Non-Work Bound Students

    Science.gov (United States)

    Creed, Peter A.; Patton, Wendy; Hood, Michelle

    2010-01-01

    We surveyed 506 Australian high school students on career development (exploration, planning, job-knowledge, decision-making, indecision), personal functioning (well-being, self-esteem, life satisfaction, school satisfaction) and control variables (parent education, school achievement), and tested differences among work-bound, college-bound and…

  3. Highly active, bi-functional and metal-free B4C-nanoparticle-modified graphite felt electrodes for vanadium redox flow batteries

    Science.gov (United States)

    Jiang, H. R.; Shyy, W.; Wu, M. C.; Wei, L.; Zhao, T. S.

    2017-10-01

    The potential of B4C as a metal-free catalyst for vanadium redox reactions is investigated by first-principles calculations. Results show that the central carbon atom of B4C can act as a highly active reaction site for redox reactions, due primarily to the abundant unpaired electrons around it. The catalytic effect is then verified experimentally by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests, both of which demonstrate that B4C nanoparticles can enhance the kinetics for both V2+/V3+ and VO2+/VO2+ redox reactions, indicating a bi-functional effect. The B4C-nanoparticle-modified graphite felt electrodes are finally prepared and tested in vanadium redox flow batteries (VRFBs). It is shown that the batteries with the prepared electrodes exhibit energy efficiencies of 88.9% and 80.0% at the current densities of 80 and 160 mA cm-2, which are 16.6% and 18.8% higher than those with the original graphite felt electrodes. With a further increase in current densities to 240 and 320 mA cm-2, the batteries can still maintain energy efficiencies of 72.0% and 63.8%, respectively. All these results show that the B4C-nanoparticle-modified graphite felt electrode outperforms existing metal-free catalyst modified electrodes, and thus can be promising electrodes for VRFBs.

  4. Understanding the corrosion behavior of isomorphous Cu–Ni alloy from its electron work function

    Energy Technology Data Exchange (ETDEWEB)

    Huang, X.C.; Lu, H.; Li, D.Y., E-mail: dongyang.li@ualberta.ca

    2016-04-15

    The electrode potential or galvanic series is usually used to reflect the nobility of metals and semi-metals. However, this potential is environment-dependent and the intrinsic nobility of a metal is ultimately governed by its electron stability, which can be represented by the electron work function (EWF). This article reports our studies on the corrosion behavior of isomorphous Cu–Ni alloy in HCl and NaCl solutions, respectively. It was demonstrated that the EWF of the alloy increased as the Ni concentration was increased, so did the corrosion resistance in the acidic solution. In the sodium chloride solution, however, the trend was reversed due to adsorption, hydrolysis and the formation of oxide scale on Cu-rich samples, which more or less prevented them from further corrosion in this solution. In order to confirm this, corrosive wear tests were performed to analyze the performance of the alloy when the effect of oxide scale was eliminated or minimized by the mechanical action. - Highlights: • Increasing %Ni resulted in higher overall electron work function of Cu–Ni alloy. • Higher EWF corresponded to higher resistance to corrosion in a HCl solution. • Trend was reversed in a NaCl solution due to the formation of oxide scale. • During slurry-jet tests, alloys with higher EWFs performed better.

  5. Understanding the corrosion behavior of isomorphous Cu–Ni alloy from its electron work function

    International Nuclear Information System (INIS)

    Huang, X.C.; Lu, H.; Li, D.Y.

    2016-01-01

    The electrode potential or galvanic series is usually used to reflect the nobility of metals and semi-metals. However, this potential is environment-dependent and the intrinsic nobility of a metal is ultimately governed by its electron stability, which can be represented by the electron work function (EWF). This article reports our studies on the corrosion behavior of isomorphous Cu–Ni alloy in HCl and NaCl solutions, respectively. It was demonstrated that the EWF of the alloy increased as the Ni concentration was increased, so did the corrosion resistance in the acidic solution. In the sodium chloride solution, however, the trend was reversed due to adsorption, hydrolysis and the formation of oxide scale on Cu-rich samples, which more or less prevented them from further corrosion in this solution. In order to confirm this, corrosive wear tests were performed to analyze the performance of the alloy when the effect of oxide scale was eliminated or minimized by the mechanical action. - Highlights: • Increasing %Ni resulted in higher overall electron work function of Cu–Ni alloy. • Higher EWF corresponded to higher resistance to corrosion in a HCl solution. • Trend was reversed in a NaCl solution due to the formation of oxide scale. • During slurry-jet tests, alloys with higher EWFs performed better.

  6. Ion pressure and work function in an effusion experiment

    International Nuclear Information System (INIS)

    Nikitin, M.I.

    1986-01-01

    The relationship between ion flow and ion pressure is examined from the point of view of the existence of a plasma in an effusion chamber. It is shown that this relationship is nonlinear, and a method is described to calculate it for specific experimental conditions. An analysis is made of the dependence of ion pressure and the work function of the inside surface of the effusion chamber on the composition of the condensed or gas phase

  7. Improving Assessment of Work Related Mental Health Function Using the Work Disability Functional Assessment Battery (WD-FAB).

    Science.gov (United States)

    Marfeo, Elizabeth E; Ni, Pengsheng; McDonough, Christine; Peterik, Kara; Marino, Molly; Meterko, Mark; Rasch, Elizabeth K; Chan, Leighton; Brandt, Diane; Jette, Alan M

    2018-03-01

    Purpose To improve the mental health component of the Work Disability Functional Assessment Battery (WD-FAB), developed for the US Social Security Administration's (SSA) disability determination process. Specifically our goal was to expand the WD-FAB scales of mood & emotions, resilience, social interactions, and behavioral control to improve the depth and breadth of the current scales and expand the content coverage to include aspects of cognition & communication function. Methods Data were collected from a random, stratified sample of 1695 claimants applying for the SSA work disability benefits, and a general population sample of 2025 working age adults. 169 new items were developed to replenish the WD-FAB scales and analyzed using factor analysis and item response theory (IRT) analysis to construct unidimensional scales. We conducted computer adaptive test (CAT) simulations to examine the psychometric properties of the WD-FAB. Results Analyses supported the inclusion of four mental health subdomains: Cognition & Communication (68 items), Self-Regulation (34 items), Resilience & Sociability (29 items) and Mood & Emotions (34 items). All scales yielded acceptable psychometric properties. Conclusions IRT methods were effective in expanding the WD-FAB to assess mental health function. The WD-FAB has the potential to enhance work disability assessment both within the context of the SSA disability programs as well as other clinical and vocational rehabilitation settings.

  8. Hearing aid noise suppression and working memory function

    DEFF Research Database (Denmark)

    Neher, Tobias; Wagener, Kirsten C.; Fischer, Rosa-Linde

    2018-01-01

    OBJECTIVE: Research findings concerning the relation between benefit from hearing aid (HA) noise suppression and working memory function are inconsistent. The current study thus investigated the effects of three noise suppression algorithms on auditory working memory and the relation with reading......-to-noise ratio (SNR) improvement. Auditory working memory was assessed at +6 dB SNR using listening span and N-back paradigms. STUDY SAMPLE: Twenty experienced HA users ages 55-80 with large differences in reading span. RESULTS: For the listening span measurements, there was an influence of HA setting...... on sentence-final word recognition and recall, with the directional microphones leading to ~6% better performance than the single-channel noise reduction. For the N-back measurements, there was substantial test-retest variability and no influence of HA setting. No interactions with reading span were found...

  9. Hearing aid noise suppression and working memory function

    DEFF Research Database (Denmark)

    Fischer, Rosa-Linde; Neher, Tobias; Wagener, Kirsten C.

    Research findings concerning the relation between outcome from hearing aid (HA) noise suppression and working memory function are unclear. The current study thus investigated the effects of three noise suppression algorithms on auditory working memory as well as the relation with reading span......) improvement. Auditory working memory was assessed at +6 dB SNR using a listening span and an N-back paradigm. Twenty experienced HA users aged 55-80 yr with large differences in reading span took part. For the listening span measurements, there was an influence of HA setting on final word recognition...... and recall, with the directional microphone setting leading to approx. 6% better performance than the single-channel noise reduction setting. For the N-back measurements, there was substantial test-retest variability and no influence of HA setting. No interactions with reading span were found. These results...

  10. Working Memory in the Service of Executive Control Functions.

    Science.gov (United States)

    Mansouri, Farshad A; Rosa, Marcello G P; Atapour, Nafiseh

    2015-01-01

    Working memory is a type of short-term memory which has a crucial cognitive function that supports ongoing and upcoming behaviors, allowing storage of information across delay periods. The content of this memory may typically include tangible information about features such as the shape, color or texture of an object, and its location and motion relative to the body, as well as phonological information. The neural correlate of working memory has been found in different brain areas that are involved in organizing perceptual or motor functions. In particular, neuronal activity in prefrontal areas encodes task-related information corresponding to working memory across delay periods, and lesions in the prefrontal cortex severely affect the ability to retain this type of memory. Recent studies have further expanded the scope and possible role of working memory by showing that information of a more abstract nature (including a behavior-guiding rule, or the occurrence of a conflict in information processing) can also be maintained in short-term memory, and used for adjusting the allocation of executive control in dynamic environments. It has also been shown that neuronal activity in the prefrontal cortex encodes and maintains information about such abstract entities. These findings suggest that the prefrontal cortex plays crucial roles in the organization of goal-directed behavior by supporting many different mnemonic processes, which maintain a wide range of information required for the executive control of ongoing and upcoming behaviors.

  11. Functional Imaging of Working Memory and Peripheral Endothelial Function in Middle-Aged Adults

    Science.gov (United States)

    Gonzales, Mitzi M.; Tarumi, Takashi; Tanaka, Hirofumi; Sugawara, Jun; Swann-Sternberg, Tali; Goudarzi, Katayoon; Haley, Andreana P.

    2010-01-01

    The current study examined the relationship between a prognostic indicator of vascular health, flow-mediated dilation (FMD), and working memory-related brain activation in healthy middle-aged adults. Forty-two participants underwent functional magnetic resonance imaging while completing a 2-Back working memory task. Brachial artery…

  12. Selection of Mother Wavelet Functions for Multi-Channel EEG Signal Analysis during a Working Memory Task

    Directory of Open Access Journals (Sweden)

    Noor Kamal Al-Qazzaz

    2015-11-01

    Full Text Available We performed a comparative study to select the efficient mother wavelet (MWT basis functions that optimally represent the signal characteristics of the electrical activity of the human brain during a working memory (WM task recorded through electro-encephalography (EEG. Nineteen EEG electrodes were placed on the scalp following the 10–20 system. These electrodes were then grouped into five recording regions corresponding to the scalp area of the cerebral cortex. Sixty-second WM task data were recorded from ten control subjects. Forty-five MWT basis functions from orthogonal families were investigated. These functions included Daubechies (db1–db20, Symlets (sym1–sym20, and Coiflets (coif1–coif5. Using ANOVA, we determined the MWT basis functions with the most significant differences in the ability of the five scalp regions to maximize their cross-correlation with the EEG signals. The best results were obtained using “sym9” across the five scalp regions. Therefore, the most compatible MWT with the EEG signals should be selected to achieve wavelet denoising, decomposition, reconstruction, and sub-band feature extraction. This study provides a reference of the selection of efficient MWT basis functions.

  13. Glassy carbon electrode modified with horse radish peroxidase/organic nucleophilic-functionalized carbon nanotube composite for enhanced electrocatalytic oxidation and efficient voltammetric sensing of levodopa

    Energy Technology Data Exchange (ETDEWEB)

    Shoja, Yalda; Rafati, Amir Abbas, E-mail: aa_rafati@basu.ac.ir; Ghodsi, Javad

    2016-01-01

    A novel and selective enzymatic biosensor was designed and constructed for voltammetric determination of levodopa (L-Dopa) in aqueous media (phosphate buffer solution, pH = 7). Biosensor development was on the basis of to physically immobilizing of horse radish peroxidase (HRP) as electrochemical catalyst by sol–gel on glassy carbon electrode modified with organic nucleophilic carbon nanotube composite which in this composite p-phenylenediamine (pPDA) as organic nucleophile chemically bonded with functionalized MWCNT (MWCNT-COOH). The results of this study suggest that prepared bioorganic nucleophilic carbon nanotube composite (HRP/MWCNT-pPDA) shows fast electron transfer rate for electro oxidation of L-Dopa because of its high electrochemical catalytic activity toward the oxidation of L-Dopa, more −NH{sub 2} reactive sites and large effective surface area. Also in this work we measured L-Dopa in the presence of folic acid and uric acid as interferences. The proposed biosensor was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), FT-IR spectroscopy and cyclic voltammetry (CV). The differential pulse voltammetry (DPV) was used for determination of L-Dopa from 0.1 μM to 1.9 μM with a low detection limit of 40 nM (for S/N = 3) and sensitivity was about 35.5 μA/μM. Also this biosensor has several advantages such as rapid response, high stability and reproducibility. - Highlights: • Glassy carbon electrode modified by a novel composite in which pPDA as nucleophile is chemically attached to MWCNTs. • The developed biosensor exhibited excellent electrocatalytic activity in electrochemically determination of L-Dopa. • The biosensor showed acceptable sensitivity, reproducibility, detection limit, selectivity and stability. • MWCNT-pPDA provides a good electrical conductivity and large effective surface area for enzyme immobilization.

  14. Phosphomolybdic acid functionalized graphene loading copper nanoparticles modified electrodes for non-enzymatic electrochemical sensing of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jiaoyan; Cao, Xiyue [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Xia, Jianfei, E-mail: xiajianfei@126.com [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Gong, Shida [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Wang, Zonghua, E-mail: wangzonghua@qdu.edu.cn [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Lu, Lin [College of Chemistry and Chemical Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles, Laboratory of Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Zibo Normal College, Zibo, Shandong 255100 (China)

    2016-08-31

    A sensitive non-enzymatic glucose electrochemical biosensor (Cu/PMo{sub 12}-GR/GCE) was developed based on the combination of copper nanoparticles (CuNPs) and phosphomolybdic acid functionalized graphene (PMo{sub 12}-GR). PMo{sub 12}-GR films were modified on the surface of glassy carbon electrode (GCE) through electrostatic self-assembly with the aid of poly diallyl dimethyl ammonium chloride (PDDA). Then CuNPs were successfully decorated onto the PMo{sub 12}-GR modified GCE through electrodeposition. The morphology of Cu/PMo{sub 12}-GR/GCE was characterized by scanning electron microscope (SEM). Cyclic voltammetry (CV) and chronoamperometry were used to investigate the electrochemical performances of the biosensor. The results indicated that the modified electrode displayed a synergistic effect of PMo{sub 12}-GR sheets and CuNPs towards the electro-oxidation of glucose in the alkaline solution. At the optimal detection potential of 0.50 V, the response towards glucose presented a linear response ranging from 0.10 μM to 1.0 mM with a detection limit of 3.0 × 10{sup −2} μM (S/N = 3). In addition, Cu/PMo{sub 12}-GR/GCE possessed a high selectivity, good reproducibility, excellent stability and acceptable recovery, which indicating the potential application in clinical field. - Highlights: • Cu/PMo{sub 12}-GR/GCE as a non-enzymatic glucose electrochemical sensor. • PMo{sub 12} is efficient for the uniform growth of Cu-NPs and electron transport. • The sensor exhibits good sensitivity and specificity towards glucose.

  15. A sensitive electrochemical sensor for paracetamole based on a glassy carbon electrode modified with multiwalled carbon nanotubes and dopamine nanospheres functionalized with gold nanoparticles

    International Nuclear Information System (INIS)

    Liu, Xue; Wang, Ling-Ling; Wang, Ya-Ya; Zhang, Xiao-Yan

    2014-01-01

    We describe an electrochemical sensor for paracetamole that is based on a glassy carbon electrode modified with multiwalled carbon nanotubes and dopamine nanospheres functionalized with gold nanoparticles. The functionalized nanospheres were prepared by a chemical route and characterized by scanning electron microscopy. The well-dispersed gold nanoparticles were anchored on the dopamine nanosphere via a chemical reduction of the gold precursor. The stepwise fabrication of the modified electrode and its electrochemical response to paracetamole were evaluated using electrochemical impedance spectroscopy and cyclic voltammetry. The modified electrode displayed improved electrocatalytic activity towards paracetamole, a lower oxidation potential (371 mV), and a larger peak current when compared to a bare electrode or other modified electrodes. The kinetic parameters governing the electro-oxidation of paracetamole were studied, and the analytical conditions were optimized. The peak current was linearly related to the concentration of paracetamole in 0.8–400 μM range, and the detection limit was 50 nM (at an SNR of 3). The method was successfully applied to the determination of paracetamole in spiked human urine samples and gave recoveries between 95.3 and 105.2 %. (author)

  16. Radiologic and functional evaluation of electrode dislocation from the scala tympani to the scala vestibuli in patients with cochlear implants.

    Science.gov (United States)

    Fischer, N; Pinggera, L; Weichbold, V; Dejaco, D; Schmutzhard, J; Widmann, G

    2015-02-01

    Localization of the electrode after cochlear implantation seems to have an impact on auditory outcome, and conebeam CT has emerged as a reliable method for visualizing the electrode array position within the cochlea. The aim of this retrospective study was to evaluate the frequency and clinical impact of scalar dislocation of various electrodes and surgical approaches and to evaluate its influence on auditory outcome. This retrospective single-center study analyzed a consecutive series of 63 cochlear implantations with various straight electrodes. The placement of the electrode array was evaluated by using multiplanar reconstructed conebeam CT images. For the auditory outcome, we compared the aided hearing thresholds and the charge units of maximum comfortable loudness level at weeks 6, 12, and 24 after implantation. In 7.9% of the cases, the electrode array showed scalar dislocation. In all cases, the electrode array penetrated the basal membrane within 45° of the electrode insertion. All 3 cases of cochleostomy were dislocated in the first 45° segment. No hearing differences were noted, but the charge units of maximum comfortable loudness level seemed to increase with time in patients with dislocations. The intracochlear dislocation rate of various straight electrodes detected by conebeam CT images is relatively low. Scalar dislocation may not negatively influence the hearing threshold but may require an increase of the necessary stimulus charge and should be reported by the radiologist. © 2015 by American Journal of Neuroradiology.

  17. On the impacts of working memory training on executive functioning

    Directory of Open Access Journals (Sweden)

    Tiina eSalminen

    2012-06-01

    Full Text Available Recent studies have reported improvements in a variety of cognitive functions following sole working memory (WM training. In spite of the emergence of several successful training paradigms, the scope of transfer effects has remained mixed. This is most likely due to the heterogeneity of cognitive functions that have been measured and tasks that have been applied. In the present study, we approached this issue systematically by investigating transfer effects from WM training to different aspects of executive functioning. Our training task was a demanding WM task that requires simultaneous performance of a visual and an auditory n-back task, while the transfer tasks tapped WM updating, coordination of the performance of multiple simultaneous tasks (i.e., dual-tasks and sequential tasks (i.e., task switching, and the temporal distribution of attentional processing. Additionally, we examined whether WM training improves reasoning abilities; a hypothesis that has so far gained mixed support. Following training, participants showed improvements in the trained task as well as in the transfer WM updating task. As for the other executive functions, trained participants improved in a task switching situation and in attentional processing. There was no transfer to the dual-task situation or to reasoning skills. These results therefore confirm previous findings that WM can be trained, and additionally, they show that the training effects can generalize to various other tasks tapping on executive functions.

  18. Fabrication of a three-electrode battery using hydrogen-storage materials

    Science.gov (United States)

    Roh, Chi-Woo; Seo, Jung-Yong; Moon, Hyung-Seok; Park, Hyun-Young; Nam, Na-Yun; Cho, Sung Min; Yoo, Pil J.; Chung, Chan-Hwa

    2015-04-01

    In this study, an energy storage device using a three-electrode battery is fabricated. The charging process takes place during electrolysis of the alkaline electrolyte where hydrogen is stored at the palladium bifunctional electrode. Upon discharging, power is generated by operating the alkaline fuel cell using hydrogen which is accumulated in the palladium hydride bifunctional electrode during the charging process. The bifunctional palladium electrode is prepared by electrodeposition using a hydrogen bubble template followed by a galvanic displacement reaction of platinum in order to functionalize the electrode to work not only as a hydrogen storage material but also as an anode in a fuel cell. This bifunctional electrode has a sufficiently high surface area and the platinum catalyst populates at the surface of electrode to operate the fuel cell. The charging and discharging performance of the three-electrode battery are characterized. In addition, the cycle stability is investigated.

  19. Comparing two methods to record maximal voluntary contractions and different electrode positions in recordings of forearm extensor muscle activity: Refining risk assessments for work-related wrist disorders.

    Science.gov (United States)

    Dahlqvist, Camilla; Nordander, Catarina; Granqvist, Lothy; Forsman, Mikael; Hansson, Gert-Åke

    2018-01-01

    Wrist disorders are common in force demanding industrial repetitive work. Visual assessment of force demands have a low reliability, instead surface electromyography (EMG) may be used as part of a risk assessment for work-related wrist disorders. For normalization of EMG recordings, a power grip (hand grip) is often used as maximal voluntary contraction (MVC) of the forearm extensor muscles. However, the test-retest reproducibility is poor and EMG amplitudes exceeding 100% have occasionally been recorded during work. An alternative MVC is resisted wrist extension, which may be more reliable. To compare hand grip and resisted wrist extension MVCs, in terms of amplitude and reproducibility, and to examine the effect of electrode positioning. Twelve subjects participated. EMG from right forearm extensors, from four electrode pairs, was recorded during MVCs, on three separate occasions. The group mean EMG amplitudes for resisted wrist extension were 1.2-1.7 times greater than those for hand grip. Resisted wrist extension showed better reproducibility than hand grip. The results indicate that the use of resisted wrist extension is a more accurate measurement of maximal effort of wrist extensor contractions than using hand grip and should increase the precision in EMG recordings from forearm extensor muscles, which in turn will increase the quality of risk assessments that are based on these.

  20. Fabrication and Measurement of Low Work Function Cesiated Dispenser Photocathodes

    CERN Document Server

    Moody, Nathan A; Jensen, Kevin

    2005-01-01

    Photoinjector performance is a limiting factor in the continued development of high powered FELs and electron beam-based accelerators. Presently available photocathodes are plagued with limited efficiency and short lifetime in an RF-gun environment, due to contamination or evaporation of a photosensitive surface layer. An ideal photocathode should have high efficiency at long wavelengths, long lifetime in practical vacuum environments, and prompt emission. Cathodes with high efficiency typically have limited lifetime, and vice versa, and the needs of the photocathode are generally at odds with those of the drive laser. A potential solution is the low work function dispenser cathode, where lifetime issues are overcome by periodic in situ regeneration that restores the photosensitive surface layer, analogous to those used in the microwave power tube industry. This work reports on the fabrication techniques and performance of cesiated metal photocathodes and cesiated dispenser cathodes, with a focus on understan...

  1. Preparation of catechol-linked chitosan/carbon nanocomposite-modified electrode and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Jirimali, Harishchandra Digambar; Saravanakumar, Duraisamy; Shin, Woon Sup [Dept. of Chemistry and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul (Korea, Republic of)

    2015-04-15

    In this study, we report the synthesis of 2,3-dihydroxybenzaldehyde (catechol)-linked chitosan (cat-chitosan) and the preparation of its composite with carbon (cat-chitosan/carbon) to construct a catechol-modified electrode. The synthesis is similar to our previous work on hydroquinone–chitosan/carbon composite electrode. We synthesized catechol-linked chitosan polymer and prepared the its composite electrode with carbon. The catchitosan/carbon composite electrode shows a reversible confined redox behavior by the catechol functional group. The electrode catalyzes the oxidation of NADH. It has Cu{sup 2+} ion-binding capability and its binding constant 8.7 μM.

  2. Preparation of catechol-linked chitosan/carbon nanocomposite-modified electrode and its applications

    International Nuclear Information System (INIS)

    Jirimali, Harishchandra Digambar; Saravanakumar, Duraisamy; Shin, Woon Sup

    2015-01-01

    In this study, we report the synthesis of 2,3-dihydroxybenzaldehyde (catechol)-linked chitosan (cat-chitosan) and the preparation of its composite with carbon (cat-chitosan/carbon) to construct a catechol-modified electrode. The synthesis is similar to our previous work on hydroquinone–chitosan/carbon composite electrode. We synthesized catechol-linked chitosan polymer and prepared the its composite electrode with carbon. The catchitosan/carbon composite electrode shows a reversible confined redox behavior by the catechol functional group. The electrode catalyzes the oxidation of NADH. It has Cu"2"+ ion-binding capability and its binding constant 8.7 μM.

  3. Functionalized graphene oxide-reinforced electrospun carbon nanofibers as ultrathin supercapacitor electrode

    Institute of Scientific and Technical Information of China (English)

    W.K.Chee; H.N.Lim; Y.Andou; Z.Zainal; A.A.B.Hamra; I.Harrison; M.Altarawneh; Z.T.Jiang; N.M.Huang

    2017-01-01

    Graphene oxide has been used widely as a starting precursor for applications that cater to the needs of tunable graphene. However, the hydrophilic characteristic limits their application, especially in a hydrophobic condition. Herein, a novel non-covalent surface modification approach towards graphene oxide was conducted via a UV-induced photo-polymerization technique that involves two major routes; a UV-sensitive initiator embedded via pi-pi interactions on the graphene planar rings, and the polymerization of hydrophobic polymeric chains along the surface. The functionalized graphene oxide successfully achieved the desired hydrophobicity as it displayed the characteristic of being readily dissolved in organic solvent. Upon its addition into a polymeric solution and subjected to an electrospinning process,non-woven random nanofibers embedded with graphene oxide sheets were obtained. The prepared polymeric nanofibers were subjected to two-step thermal treatments that eventually converted the polymeric chains into a carbon-rich conductive structure. A unique morphology was observed upon the addition of the functionalized graphene oxide, whereby the sheets were embedded and intercalated within the carbon nanofibers and formed a continuous structure. This reinforcement effectively enhanced the electrochemical performance of the carbon nanofibers by recording a specific capacitance of up to 140.10 F/g at the current density of 1 A/g, which was approximately three folds more than that of pristine nanofibers.It also retained the capacitance up to 96.2% after 1000 vigorous charge/discharge cycles. This functionalization technique opens up a new pathway in tuning the solubility nature of graphene oxide towards the synthesis of a graphene oxide-reinforced polymeric structure.

  4. Ultrasonic-electrodeposition of PtPd alloy nanoparticles on ionic liquid-functionalized graphene paper: towards a flexible and versatile nanohybrid electrode

    Science.gov (United States)

    Sun, Yimin; Zheng, Huaming; Wang, Chenxu; Yang, Mengmeng; Zhou, Aijun; Duan, Hongwei

    2016-01-01

    Here we fabricate a new type of flexible and versatile nanohybrid paper electrode by ultrasonic-electrodeposition of PtPd alloy nanoparticles on freestanding ionic liquid (IL)-functionalized graphene paper, and explore its multifunctional applications in electrochemical catalysis and sensing systems. The graphene-based paper materials demonstrate intrinsic flexibility, exceptional mechanical strength and high electrical conductivity, and therefore can serve as an ideal freestanding flexible electrode for electrochemical devices. Furthermore, the functionalization of graphene with IL (i.e., 1-butyl-3-methylimidazolium tetrafluoroborate) not only increases the electroactive surface area of a graphene-based nanohybrid paper electrode, but also improves the adhesion and dispersion of metal nanoparticles on the paper surface. These unique attributes, combined with the merits of an ultrasonic-electrodeposition method, lead to the formation of PtPd alloy nanoparticles on IL-graphene paper with high loading, uniform distribution, controlled morphology and favourable size. Consequently, the resultant nanohybrid paper electrode exhibits remarkable catalytic activity as well as excellent cycle stability and improved anti-poisoning ability towards electrooxidation of fuel molecules such as methanol and ethanol. Furthermore, for nonenzymatic electrochemical sensing of some specific biomarkers such as glucose and reactive oxygen species, the nanohybrid paper electrode shows high selectivity, sensitivity and biocompatibility in these bio-catalytic processes, and can be used for real-time tracking hydrogen peroxide secretion by living human cells. All these features demonstrate its promising application as a versatile nanohybrid electrode material in flexible and lightweight electrochemical energy conversion and biosensing systems such as bendable on-chip power sources, wearable/implantable detectors and in vivo micro-biosensors.Here we fabricate a new type of flexible and

  5. Electropolymerization of a poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes counter electrode for dye-sensitized solar cells and characterization of its performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jun, E-mail: zhangjundoc@sina.co [School of Chemistry and Chemical Engineering, Inner Mongolia University, 235 West University Road, Hohhot 010021 (China); Li Xiaoxue [School of Chemistry and Chemical Engineering, Inner Mongolia University, 235 West University Road, Hohhot 010021 (China); Guo Wei [College of Environmental and Resource Sciences, Inner Mongolia University, 235 West University Road, Hohhot 010021 (China); Hreid Tubshin [School of Chemistry and Chemical Engineering, Inner Mongolia University, 235 West University Road, Hohhot 010021 (China); Hou Jinfeng [Test Center, Inner Mongolia University of Technology, 49 Aimin Street, Xincheng District, Hohhot 010051 (China); Su Haiquan [School of Chemistry and Chemical Engineering, Inner Mongolia University, 235 West University Road, Hohhot 010021 (China); Yuan Zhuobin [College of Chemistry and Chemical Engineering, Graduate University of the Chinese Academy of Sciences, 19(A) Yuquan Road, Beijing 100049 (China)

    2011-03-30

    Graphical abstract: Display Omitted Research highlights: PEDOT-MWCNT and PEDOT as the counter electrodes of DSSCs. The counter electrodes fabricated by a electropolymerization method. PEDOT-MWCNT films were more porous than PEDOT films. The energy conversion efficiency with PEDOT-MWCNT was 13.0% higher than with PEDOT. - Abstract: Composite films of poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes (PEDOT-MWCNT) were fabricated by a simple oxidative electropolymerization method. These films were formed on fluorine-doped, tin oxide, glass substrates as counter electrodes (CEs) of platinum-free, dye-sensitized solar cells (DSSCs). The surface morphology, formation mechanism and electrochemical nature of PEDOT-MWCNT films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV) and alternating current (AC) impedance spectroscopy. The SEM and AFM images showed that PEDOT-MWCNT films were more porous than PEDOT films. CV and AC impedance spectroscopy revealed that the PEDOT-MWCNT electrode had higher electrocatalytic activity for the I{sub 3}{sup -}/I{sup -} redox reaction and a smaller charge transfer resistance than the PEDOT electrodes. The energy conversion efficiency of the DSSC with a PEDOT-MWCNT CE was 13.0% higher than with a PEDOT CE using the same conditions with a ruthenium sensitizer.

  6. Electropolymerization of a poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes counter electrode for dye-sensitized solar cells and characterization of its performance

    International Nuclear Information System (INIS)

    Zhang Jun; Li Xiaoxue; Guo Wei; Hreid Tubshin; Hou Jinfeng; Su Haiquan; Yuan Zhuobin

    2011-01-01

    Graphical abstract: Display Omitted Research highlights: → PEDOT-MWCNT and PEDOT as the counter electrodes of DSSCs. → The counter electrodes fabricated by a electropolymerization method. → PEDOT-MWCNT films were more porous than PEDOT films. → The energy conversion efficiency with PEDOT-MWCNT was 13.0% higher than with PEDOT. - Abstract: Composite films of poly(3,4-ethylenedioxythiophene) and functionalized, multi-walled, carbon nanotubes (PEDOT-MWCNT) were fabricated by a simple oxidative electropolymerization method. These films were formed on fluorine-doped, tin oxide, glass substrates as counter electrodes (CEs) of platinum-free, dye-sensitized solar cells (DSSCs). The surface morphology, formation mechanism and electrochemical nature of PEDOT-MWCNT films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV) and alternating current (AC) impedance spectroscopy. The SEM and AFM images showed that PEDOT-MWCNT films were more porous than PEDOT films. CV and AC impedance spectroscopy revealed that the PEDOT-MWCNT electrode had higher electrocatalytic activity for the I 3 - /I - redox reaction and a smaller charge transfer resistance than the PEDOT electrodes. The energy conversion efficiency of the DSSC with a PEDOT-MWCNT CE was 13.0% higher than with a PEDOT CE using the same conditions with a ruthenium sensitizer.

  7. Mobile Device Applications for the Visualization of Functional Connectivity Networks and EEG Electrodes: iBraiN and iBraiNEEG.

    Science.gov (United States)

    Rojas, Gonzalo M; Fuentes, Jorge A; Gálvez, Marcelo

    2016-01-01

    Multiple functional MRI (fMRI)-based functional connectivity networks were obtained by Yeo et al. (2011), and the visualization of these complex networks is a difficult task. Also, the combination of functional connectivity networks determined by fMRI with electroencephalography (EEG) data could be a very useful tool. Mobile devices are becoming increasingly common among users, and for this reason, we describe here two applications for Android and iOS mobile devices: one that shows in an interactive way the seven Yeo functional connectivity networks, and another application that shows the relative position of 10-20 EEG electrodes with Yeo's seven functional connectivity networks.

  8. Measuring current emission and work functions of large thermionic cathodes

    International Nuclear Information System (INIS)

    Fortgang, C.M.

    2001-01-01

    As one component of the nations Stockpile Stewardship program, Los Alamos National Laboratory is constructing a 20 MeV, 2 kA (with a 4 kA upgrade capability), 3ps induction linac for doing x-ray radiography of explosive devices. The linac is one leg of a facility called the Dual-Axis Radiography Hydrodynamic Test Facility (DARHT). The electron gun is designed to operate at 3.2 MV. The gun is a Pierce type design and uses a 6.5' cathode for 2 kA operation and an 8' cathode for 4 kA operation. We have constructed a small facility called the Cathode Test Stand (CTS) to investigate engineering and physics issues regarding large thermionic dispenser-cathodes. In particular, we have looked at the issues of temperature uniformity on the cathode surface and cathode quality as measured by its work function. We have done thermal imaging of both 8' and 6.5' cathodes. Here we report on measurements of the cathode work function, both the average value and how it vanes across the face of the cathode.

  9. Physical and chemical characterization of adsorbed protein onto gold electrode functionalized with Tunisian coral and nacre

    International Nuclear Information System (INIS)

    Hamza, Samir; Bouchemi, Meryem; Slimane, Noureddine; Azari, Zitouni

    2013-01-01

    Bone substitutes are more and more used in bone surgery because of their biologic safety, clinic efficiency and facility to synthesize. Bone substitutes with active osteogenic properties, associating biomaterials with organic macromolecule components of the extracellular matrix (protein, GAG) are recommended. Nevertheless, we should have a simple technique to control interactions between proteins and the material. Natural coral and nacre have been found to be impressive bone graft substitutes. In this work, we characterize nacre and coral powder using energy dispersive X-ray analysis (EDX). We used electrochemical impedance spectroscopy (EIS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to evaluate bovine serum albumin (BSA) as model protein, adsorbed to these biomaterial surfaces. In order to understand the nacre/coral-protein interfacial compatibility, it is necessary to investigate the wettability. - Highlights: ► The structural and physico-chemical properties of material operated as a bone substitute. ► This study investigated the adsorption of BSA onto coral and nacre. ► X-ray diffraction analysis of coral and nacre. ► Simple technique to control interactions between proteins and the biomaterial.

  10. Physical and chemical characterization of adsorbed protein onto gold electrode functionalized with Tunisian coral and nacre

    Energy Technology Data Exchange (ETDEWEB)

    Hamza, Samir, E-mail: samir.hamza@insat.rnu.tn [Biomaterials and Biomechanics Laboratory, National Institute M.T. Kassab of Orthopedic, 2010 La Manouba, Tunis (Tunisia); National Institute of Applied Sciences and Technology, Centre Urbain Nord, Box 676, 1080 Tunis cedex (Tunisia); Bouchemi, Meryem, E-mail: bouchemimeryem@yahoo.fr [National Institute of Applied Sciences and Technology, Centre Urbain Nord, Box 676, 1080 Tunis cedex (Tunisia); Slimane, Noureddine, E-mail: labiomecanique@yahoo.fr [Biomaterials and Biomechanics Laboratory, National Institute M.T. Kassab of Orthopedic, 2010 La Manouba, Tunis (Tunisia); Azari, Zitouni, E-mail: azari@univ-metz.fr [Laboratory of Biomechanics, Polymer and Structures Mechanics, National School of Engineers of Metz, France, 1 route d' Ars Laquenexy, CS 65820 57078 Metz cedex 03 (France)

    2013-01-01

    Bone substitutes are more and more used in bone surgery because of their biologic safety, clinic efficiency and facility to synthesize. Bone substitutes with active osteogenic properties, associating biomaterials with organic macromolecule components of the extracellular matrix (protein, GAG) are recommended. Nevertheless, we should have a simple technique to control interactions between proteins and the material. Natural coral and nacre have been found to be impressive bone graft substitutes. In this work, we characterize nacre and coral powder using energy dispersive X-ray analysis (EDX). We used electrochemical impedance spectroscopy (EIS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to evaluate bovine serum albumin (BSA) as model protein, adsorbed to these biomaterial surfaces. In order to understand the nacre/coral-protein interfacial compatibility, it is necessary to investigate the wettability. - Highlights: Black-Right-Pointing-Pointer The structural and physico-chemical properties of material operated as a bone substitute. Black-Right-Pointing-Pointer This study investigated the adsorption of BSA onto coral and nacre. Black-Right-Pointing-Pointer X-ray diffraction analysis of coral and nacre. Black-Right-Pointing-Pointer Simple technique to control interactions between proteins and the biomaterial.

  11. Highly Conductive Aromatic Functionalized Multi-Walled Carbon Nanotube for Inkjet Printable High Performance Supercapacitor Electrodes.

    Directory of Open Access Journals (Sweden)

    Sanjeev K Ujjain

    Full Text Available We report the functionalization of multiwalled carbon nanotubes (MWCNT via the 1,3-dipolar [3+2] cycloaddition of aromatic azides, which resulted in a detangled CNT as shown by transmission electron microscopy (TEM. Carboxylic moieties (-COOH on aromatic azide result in highly stable aqueous dispersion (max. conc. ~ 10 mg/mL H2O, making the suitable for inkjet printing. Printed patterns on polyethylene terephthalate (PET flexible substrate exhibit low sheet resistivity ~65 Ω. cm, which is attributed to enhanced conductivity. Fabricated Supercapacitors (SC assembled using these printed substrates exhibit good electrochemical performance in organic as well as aqueous electrolytes. High energy and power density (57.8 Wh/kg and 0.85 kW/kg in 1M H2SO4 aqueous electrolyte demonstrate the excellent performance of the proposed supercapacitor. Capacitive retention varies from ~85-94% with columbic efficiency ~95% after 1000 charge/discharge cycles in different electrolytes, demonstrating the excellent potential of the device for futuristic power applications.

  12. Asymmetric supercapacitors based on functional electrospun carbon nanofiber/manganese oxide electrodes with high power density and energy density

    Science.gov (United States)

    Lin, Sheng-Chi; Lu, Yi-Ting; Chien, Yu-An; Wang, Jeng-An; You, Ting-Hsuan; Wang, Yu-Sheng; Lin, Chih-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

    2017-09-01

    Carbon nanofibers modified with carboxyl groups (CNF-COOH) possessing good wettability and high porosity are homogeneously deposited with amorphous manganese dioxide (amorphous MnO2) by potentiodynamic deposition for asymmetric super-capacitors (ASCs). The potential-cycling in 1 M H2SO4 successfully enhances the hydrophilicity of carbonized polymer nanofibers and facilitates the access of electrolytes within the CNF-COOH matrix. This modification favors the deposition of amorphous MnO2 and improves its electrochemical utilization. In this composite, MnO2 homogeneously dispersed onto CNF-COOH provides desirable pseudocapacitance and the CNF-COOH network works as the electron conductor. The composite of CNF-COOH@MnO2-20 shows a high specific capacitance of 415 F g-1 at 5 mV s-1. The capacitance retention of this composite is 94% in a 10,000-cycle test. An ASC cell consisting of this composite and activated carbon as positive and negative electrodes can be reversibly charged/discharged to a cell voltage of 2.0 V in 1 M Na2SO4 and 4 mM NaHCO3 with specific energy and power of 36.7 Wh kg-1 and 354.9 W kg-1, respectively. This ASC also shows excellent cell capacitance retention (8% decay) in the 2V, 10,000-cycle stability test, revealing superior performance.

  13. Pulse-reversal electropolymerization of polypyrrole on functionalized carbon nanotubes as composite counter electrodes in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Wang, Wei-Yan; Ting, Pan-Ning; Luo, Shu-Hui; Lin, Jeng-Yu

    2014-01-01

    Highlights: • MWCNT/PPy composite was incorporated in Pt-free DSCs. • Evenly coating of PPy on MWCNT was achieved by using pulse-reversal technique. • The DSC with theMWCNT/PPy composite reached an efficiency of 6.21%. - Abstract: In this current work, we proposed a modified two-step method to prepare multiwalled carbon nanotube/polypyrrol (MWCNT/PPy) composite counter electrodes (CEs) toward triiodide reduction in dye-sensitized solar cells (DSCs). MWCNTs were deposited onto the surface of fluorinated tin oxide (FTO) glass substrates by electrophoretic deposition, and then subjected to the PPy electropolymerization by using a pulse-reversal technique. With regard to the electropolymerization of PPy on the MWCNTs-coated FTO substrate by conventional cyclic voltammetry (CV) method (designated as MWCNT/PPy-CV CE), the MWCNT/PPy-PR CE still retrained the mesoporous morphology originating from the MWCNT conductive framework and the PPy thin film was found to be evenly coated on the MWCNT surface. According to the extensive electrochemical analyses, the mesoporous nanostructure of the MWCNT/PPy-PR CE provided increased active surface area for I 3 - reduction and facilitated the electron transport at the interface of CE/electrolyte and the redox electrolyte penetration within the CE. As a result, the DSC assembled with the MWCNT/PPy-PR CE reaches a comparable photovoltaic efficiency of 6.21% to that of the DSC based on the Pt CE (6.66%)

  14. Straightforward grafting approach for cyclam-functionalized screen-printed electrodes for selective Cu(II) determination

    International Nuclear Information System (INIS)

    Jasmin, Jean-Philippe; Ouhenia-Ouadahi, Karima; Miserque, Frédéric; Dumas, Eddy; Cannizzo, Caroline; Chaussé, Annie

    2016-01-01

    We report in this paper an original way to covalently bind the macrocyclic ligand, 1,4,8,11-tetraazacyclotetradecane (cyclam), through diazonium salt chemistry, on the surface of carbon screen-printed electrodes (SPEs). The in situ synthesis of the diazonium salt obtained from the amine precursor derived from the cyclam and its electrografting are described. X-ray Photoelectron Spectroscopy was used to characterize this functionalized surface. Owing to the strong cyclam–Cu(II) affinity, the so called SPE-cyclam can be used as electrochemical sensors for Cu(II) determination at trace levels. The influence of electroanalysis parameters such as the accumulation time and the pH of the medium were investigated. An interference study was carried out with numerous metallic cations and few interference was found for Cu(II) quantification. The described method provided a limit of detection and a limit of quantification of 1.3 × 10"−"8 M and 4.0 × 10"−"8 M, respectively. Interference study and performances show that SPE-cyclam could be considered as efficient sensors for environmental analysis.

  15. Visual working memory load-related changes in neural activity and functional connectivity.

    Directory of Open Access Journals (Sweden)

    Ling Li

    Full Text Available BACKGROUND: Visual working memory (VWM helps us store visual information to prepare for subsequent behavior. The neuronal mechanisms for sustaining coherent visual information and the mechanisms for limited VWM capacity have remained uncharacterized. Although numerous studies have utilized behavioral accuracy, neural activity, and connectivity to explore the mechanism of VWM retention, little is known about the load-related changes in functional connectivity for hemi-field VWM retention. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we recorded electroencephalography (EEG from 14 normal young adults while they performed a bilateral visual field memory task. Subjects had more rapid and accurate responses to the left visual field (LVF memory condition. The difference in mean amplitude between the ipsilateral and contralateral event-related potential (ERP at parietal-occipital electrodes in retention interval period was obtained with six different memory loads. Functional connectivity between 128 scalp regions was measured by EEG phase synchronization in the theta- (4-8 Hz, alpha- (8-12 Hz, beta- (12-32 Hz, and gamma- (32-40 Hz frequency bands. The resulting matrices were converted to graphs, and mean degree, clustering coefficient and shortest path length was computed as a function of memory load. The results showed that brain networks of theta-, alpha-, beta-, and gamma- frequency bands were load-dependent and visual-field dependent. The networks of theta- and alpha- bands phase synchrony were most predominant in retention period for right visual field (RVF WM than for LVF WM. Furthermore, only for RVF memory condition, brain network density of theta-band during the retention interval were linked to the delay of behavior reaction time, and the topological property of alpha-band network was negative correlation with behavior accuracy. CONCLUSIONS/SIGNIFICANCE: We suggest that the differences in theta- and alpha- bands between LVF and RVF

  16. Visual Working Memory Load-Related Changes in Neural Activity and Functional Connectivity

    Science.gov (United States)

    Li, Ling; Zhang, Jin-Xiang; Jiang, Tao

    2011-01-01

    Background Visual working memory (VWM) helps us store visual information to prepare for subsequent behavior. The neuronal mechanisms for sustaining coherent visual information and the mechanisms for limited VWM capacity have remained uncharacterized. Although numerous studies have utilized behavioral accuracy, neural activity, and connectivity to explore the mechanism of VWM retention, little is known about the load-related changes in functional connectivity for hemi-field VWM retention. Methodology/Principal Findings In this study, we recorded electroencephalography (EEG) from 14 normal young adults while they performed a bilateral visual field memory task. Subjects had more rapid and accurate responses to the left visual field (LVF) memory condition. The difference in mean amplitude between the ipsilateral and contralateral event-related potential (ERP) at parietal-occipital electrodes in retention interval period was obtained with six different memory loads. Functional connectivity between 128 scalp regions was measured by EEG phase synchronization in the theta- (4–8 Hz), alpha- (8–12 Hz), beta- (12–32 Hz), and gamma- (32–40 Hz) frequency bands. The resulting matrices were converted to graphs, and mean degree, clustering coefficient and shortest path length was computed as a function of memory load. The results showed that brain networks of theta-, alpha-, beta-, and gamma- frequency bands were load-dependent and visual-field dependent. The networks of theta- and alpha- bands phase synchrony were most predominant in retention period for right visual field (RVF) WM than for LVF WM. Furthermore, only for RVF memory condition, brain network density of theta-band during the retention interval were linked to the delay of behavior reaction time, and the topological property of alpha-band network was negative correlation with behavior accuracy. Conclusions/Significance We suggest that the differences in theta- and alpha- bands between LVF and RVF conditions in

  17. Functional magnetic resonance imaging in the activation of working memory

    International Nuclear Information System (INIS)

    Spitzer, M.; Kammer, T.; Bellemann, M.E.; Gueckel, F.; Georgi, M.; Gass, A.; Brix, G.

    1996-01-01

    Functional magnetic resonance imaging was used in conjunction with a letter detection task for the study of working memory in 16 normal subjects. Because of movement artifacts, data from only 9 subjects were analysed. In the activation taks, subjects responded by pressing a button whenever any presented letter was the same as the second last in the sequence. In the control condition, the subjects had to respond to a fixed letter. Hence, the activation condition and the control condition differend only subjectively, i.e., regarding the task demand, whereas the stimuli and the type and frequency of response were identical. The activation condition produced significant activation in the dorsolateral prefrontal cortex (Brodmann's areas 10, 46, and 9). In contrast to experimental tasks previsouly used rather extensively to study the prefrontal cortex, the present paradigm is characterized by its simplicity, interpretability, and its ties to known neurophysiology of the frontal cortex. (orig.) [de

  18. Mobile Device Applications for the Visualization of Functional Connectivity Networks and EEG electrodes: iBraiN and iBraiNEEG.

    Directory of Open Access Journals (Sweden)

    Gonzalo Mauricio Rojas

    2016-10-01

    Full Text Available Multiple fMRI-based functional connectivity networks were obtained by Yeo et al., and the visualization of these complex networks is a difficult task. Also, the combination of functional connectivity networks determined by fMRI with EEG data could be a very useful tool. Mobile devices are becoming increasingly common among users, and for this reason, we describe here two applications for Android and iOS mobile devices: one that shows in an interactive way the seven Yeo functional connectivity networks, and another application that shows the relative position of 10-20 EEG electrodes with Yeo’s seven functional connectivity networks.

  19. Dual functional reduced graphene oxide as photoanode and counter electrode in dye-sensitized solar cells and its exceptional efficiency enhancement

    Science.gov (United States)

    Jumeri, F. A.; Lim, H. N.; Zainal, Z.; Huang, N. M.; Pandikumar, A.; Lim, S. P.

    2015-10-01

    The dual functionalities of reduced graphene oxide (rGO) as photoanode and counter electrode in dye-sensitized solar cells (DSSCs) is explored. A titanium dioxide (TiO2) film is deposited on an indium tin oxide (ITO) glass using an in-house aerosol-assisted chemical vapor deposition method. Graphene oxide (GO) is then introduced onto the TiO2-ITO substrate, and the GO layer is successively thermally treated to rGO. The TiO2-rGO film is used as a compact layer for the photoanode of the DSSC. A layer of zinc oxide-silver (ZnO-Ag) is introduced on top of the compact layer as an active material. Its highly porous flower-shaped morphology is advantageous for the adsorption of dye. The in-situ electrochemical polymerization method used for the fabrication of polypyrrole incorporated with rGO and p-toluenesulfonate (pTS) (Ppy-rGO-pTS) on an ITO glass is used as a counter electrode for the DSSC. The DSSC assembled with the Ppy-rGO-1.0pTS counter electrode exhibites an enhanced conversion efficiency of 1.99% under solar illumination, which is better than that using conventional Pt as a counter electrode (0.08%). This is attributed to the increased contact area between the Ppy-rGO-pTS counter electrode and electrolyte, which subsequently improves the conductivity and high electrocatalytic activities of the Ppy-rGO-pTS counter electrode.

  20. Strain effects on the work function of an organic semiconductor

    KAUST Repository

    Wu, Yanfei

    2016-02-01

    Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional theory calculations. An elastic-to-plastic transition, characterized by a steep rise of the WF, occurs at ~0.05% tensile strain along the rubrene π-stacking direction. The results provide the first concrete link between mechanical strain and WF of an organic semiconductor and have important implications for understanding the connection between structural and electronic disorder in soft organic electronic materials.

  1. Strain effects on the work function of an organic semiconductor

    Science.gov (United States)

    Wu, Yanfei; Chew, Annabel R.; Rojas, Geoffrey A.; Sini, Gjergji; Haugstad, Greg; Belianinov, Alex; Kalinin, Sergei V.; Li, Hong; Risko, Chad; Brédas, Jean-Luc; Salleo, Alberto; Frisbie, C. Daniel

    2016-01-01

    Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional theory calculations. An elastic-to-plastic transition, characterized by a steep rise of the WF, occurs at ∼0.05% tensile strain along the rubrene π-stacking direction. The results provide the first concrete link between mechanical strain and WF of an organic semiconductor and have important implications for understanding the connection between structural and electronic disorder in soft organic electronic materials. PMID:26831362

  2. Cross Functional Working and Concurrent Engineering – a UK Study

    Directory of Open Access Journals (Sweden)

    H. Williams

    2000-01-01

    Full Text Available This paper reports on the preliminary results of an investigative study into the implementation of concurrent engineering applied to new product development. Concurrent (or Simultaneous engineering is the term commonly given to creating new products using multi-disciplined teams of marketing, design, manufacturing and support functions together with supplier and customers. Such techniques have produced robust, low cost quality products in short concept to market times compared to traditional ones. The research investigated design management practice and performance in a number of organisations across a range of industrial sectors in the UK by means of a questionnaire survey. The results identify the current use of a variety of design practices and methodologies such as different organisational structures, the extent of cross-functional working, the use of design and phase reviews and the use of different technologies. They indicate that companies implementing CE are more successful in time to market performance than those who don’t implement CE. Factors most influencing the successful adoption of CE are design and phase reviews, and, to a lesser extent, the use of multifunctional teams and supplier partnerships.

  3. Piperidine adsorption on two different silver electrodes: A combined surface enhanced Raman spectroscopy and density functional theory study

    International Nuclear Information System (INIS)

    Hao Yanling; Fang Yan

    2007-01-01

    The surface enhanced Raman scattering (SERS) spectra of piperidine in silver colloid solution, on roughened silver electrode and on roughened silver electrode modified with silver nanoparticles were studied, and the high-quality SERS spectra of piperidine on roughened silver electrode modified with silver nanoparticles were obtained for the first time. Surface selection rules derived from the EM enhancement model were employed to deduce piperidine orientations on the different surfaces. On the basis of this, two models of piperidine adsorbed on the surface of the silver nanoparticles were built, and DFT-B3PW91/LanL2dz was applied to calculate the Raman frequencies. It proves that, at higher potential values, the piperidine is perpendicularly standing on the roughened silver electrode surface though its lone-electron pair, but in silver colloid solution and on the silver nanoparticles modified silver electrode the piperidine molecular lies flat on the silver surface. In the meantime, the potential dependent SERS of piperidine on the modified electrode were studied

  4. Determination of total mercury in seafood by ion-selective electrodes based on a thiol functionalized ionic liquid

    Directory of Open Access Journals (Sweden)

    Juan Miao

    2018-04-01

    Full Text Available A mercury(II ion-selective electrode with an ionic liquid (IL, 1-methyl-2-butylthioimidazolium bis(trifluoromethanesulphonylimide ([C1C4Sim]NTf2 as active material was constructed. Parameters affecting the performance of the electrodes such as the dosages of the IL and carbon nanotubes and the aqueous pH values were investigated. Experimental results indicated that the optimal composition of the electrode filling material was 47.6% [C1C4Sim]NTf2, 47.6% tetrabutylphosphonium bis(trifluoromethanesulphonylimide (TBPNTf2 and 4.8% carboxylic multi-walled carbon nanotubes (MWCNTs-COOH. Under the selected conditions, the proposed electrodes showed a good linear response in the concentration range of 10−10–10−5 mol L−1 and had a detection limit of 4.1 × 10−11 mol L−1. No great interference from common metal ions was found. The proposed electrodes were applied to determine Hg2+ in seafood samples; the results were comparable to those of the direct mercury analyzer. Keywords: Ionic liquids (ILs, Mercury, Ion-selective electrodes, Carbon nanotubes, Seafood

  5. The use of regression analysis in determining reference intervals for low hematocrit and thrombocyte count in multiple electrode aggregometry and platelet function analyzer 100 testing of platelet function.

    Science.gov (United States)

    Kuiper, Gerhardus J A J M; Houben, Rik; Wetzels, Rick J H; Verhezen, Paul W M; Oerle, Rene van; Ten Cate, Hugo; Henskens, Yvonne M C; Lancé, Marcus D

    2017-11-01

    Low platelet counts and hematocrit levels hinder whole blood point-of-care testing of platelet function. Thus far, no reference ranges for MEA (multiple electrode aggregometry) and PFA-100 (platelet function analyzer 100) devices exist for low ranges. Through dilution methods of volunteer whole blood, platelet function at low ranges of platelet count and hematocrit levels was assessed on MEA for four agonists and for PFA-100 in two cartridges. Using (multiple) regression analysis, 95% reference intervals were computed for these low ranges. Low platelet counts affected MEA in a positive correlation (all agonists showed r 2 ≥ 0.75) and PFA-100 in an inverse correlation (closure times were prolonged with lower platelet counts). Lowered hematocrit did not affect MEA testing, except for arachidonic acid activation (ASPI), which showed a weak positive correlation (r 2 = 0.14). Closure time on PFA-100 testing was inversely correlated with hematocrit for both cartridges. Regression analysis revealed different 95% reference intervals in comparison with originally established intervals for both MEA and PFA-100 in low platelet or hematocrit conditions. Multiple regression analysis of ASPI and both tests on the PFA-100 for combined low platelet and hematocrit conditions revealed that only PFA-100 testing should be adjusted for both thrombocytopenia and anemia. 95% reference intervals were calculated using multiple regression analysis. However, coefficients of determination of PFA-100 were poor, and some variance remained unexplained. Thus, in this pilot study using (multiple) regression analysis, we could establish reference intervals of platelet function in anemia and thrombocytopenia conditions on PFA-100 and in thrombocytopenia conditions on MEA.

  6. A stability comparison of redox-active layers produced by chemical coupling of an osmium redox complex to pre-functionalized gold and carbon electrodes

    International Nuclear Information System (INIS)

    Boland, Susan; Foster, Kevin; Leech, Donal

    2009-01-01

    The production of stable redox active layers on electrode surfaces is a key factor for the development of practical electronic and electrochemical devices. Here, we report on a comparison of the stability of redox layers formed by covalently coupling an osmium redox complex to pre-functionalized gold and graphite electrode surfaces. Pre-treatment of gold and graphite electrodes to provide surface carboxylic acid groups is achieved via classical thiolate self-assembled monolayer formation on gold surfaces and the electro-reduction of an in situ generated aryldiazonium salt from 4-aminobenzoic acid on gold, glassy carbon and graphite surfaces. These surfaces have been characterized by AFM and electrochemical blocking studies. The surface carboxylate is then used to tether an osmium complex, [Os(2,2'-bipyridyl) 2 (4-aminomethylpyridine)Cl]PF 6 , to provide a covalently bound redox active layer, E 0 '' of 0.29 V (vs. Ag/AgCl in phosphate buffer, pH 7.4), on the pre-treated electrodes. The aryldiazonium salt-treated carbon-based surfaces showed the greatest stability, represented by a decrease of <5% in the peak current for the Os(II/III) redox transition of the immobilized complex over a 3-day period, compared to a decrease of 19% and 14% for the aryldiazonium salt treated and thiolate treated gold surfaces, respectively, over the same period

  7. Classical density functional theory and Monte Carlo simulation study of electric double layer in the vicinity of a cylindrical electrode

    Science.gov (United States)

    Zhou, Shiqi; Lamperski, Stanisław; Sokołowska, Marta

    2017-07-01

    We have performed extensive Monte-Carlo simulations and classical density functional theory (DFT) calculations of the electrical double layer (EDL) near a cylindrical electrode in a primitive model (PM) modified by incorporating interionic dispersion interactions. It is concluded that (i) in general, an unsophisticated use of the mean field (MF) approximation for the interionic dispersion interactions does not distinctly worsen the classical DFT performance, even if the salt ions considered are highly asymmetrical in size (3:1) and charge (5:1), the bulk molar concentration considered is high up to a total bulk ion packing fraction of 0.314, and the surface charge density of up to 0.5 C m-2. (ii) More specifically, considering the possible noises in the simulation, the local volume charge density profiles are the most accurately predicted by the classical DFT in all situations, and the co- and counter-ion singlet distributions are also rather accurately predicted; whereas the mean electrostatic potential profile is relatively less accurately predicted due to an integral amplification of minor inaccuracy of the singlet distributions. (iii) It is found that the layered structure of the co-ion distribution is abnormally possible only if the surface charge density is high enough (for example 0.5 C m-2) moreover, the co-ion valence abnormally influences the peak height of the first counter-ion layer, which decreases with the former. (iv) Even if both the simulation and DFT indicate an insignificant contribution of the interionic dispersion interaction to the above three ‘local’ quantities, it is clearly shown by the classical DFT that the interionic dispersion interaction does significantly influence a ‘global’ quantity like the cylinder surface-aqueous electrolyte interfacial tension, and this may imply the role of the interionic dispersion interaction in explaining the specific Hofmeister effects. We elucidate all of the above observations based on the

  8. Functional brain activation associated with working memory training and transfer.

    Science.gov (United States)

    Clark, Cameron M; Lawlor-Savage, Linette; Goghari, Vina M

    2017-09-15

    While behavioural trials of working memory (WM) training have received much attention in recent years, a lesser explored parallel approach is functional neuroimaging. A small literature has suggested a complex time course for functional activation pattern changes following WM training (i.e. not simply increasing or decreasing due to training); however, no study to date has examined such neuroplastic effects in both the training task (dual n-back) and the fluid intelligence transfer task to which the training is purported to transfer (Raven's Matrices). This study investigated neural correlates of WM training in healthy young adults randomized to six weeks of WM training, or an active control condition (processing speed training) with a pre- and post-training fMRI design. Results indicated significant reductions in activation for the WM trained group in key WM-task related areas for trained WM tasks after training compared to the processing speed active control group. The same pattern of training related decreases in activation for the WM trained group was not observed for the transfer task, which is consistent with null results for all cognitive outcomes of the present trial. The observed pattern of results suggests that repetitive practice with a complex task does indeed lead to neuroplastic processes that very likely represent the reduced demand for attentional control while sub-components of the task become more routinized with practice. We suggest that future research investigate neural correlates of WM training in populations for which WM itself is impaired and/or behavioural trials of WM training have returned more promising results. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Modeling the Lithium Ion/Electrode Battery Interface Using Fick’s Second Law of Diffusion, the Laplace Transform, Charge Transfer Functions, and a [4, 4] Padé Approximant

    Directory of Open Access Journals (Sweden)

    John H. Summerfield

    2015-01-01

    Full Text Available This work investigates a one-dimensional model for the solid-state diffusion in a LiC6/LiMnO2 rechargeable cell. This cell is used in hybrid electric vehicles. In this environment the cell experiences low frequency electrical pulses that degrade the electrodes. The model’s starting point is Fick’s second law of diffusion. The Laplace transform is used to move from time as the independent variable to frequency as the independent variable. To better understand the effect of frequency changes on the cell, a transfer function is constructed. The transfer function is a transcendental function so a Padé approximant is found to better describe the model at the origin. Consider ∂c(r,t/∂t=D∂2c(r/∂2r+(2/r(∂c(r/∂r.

  10. Effect of tDCS with an extracephalic reference electrode on cardio-respiratory and autonomic functions

    Directory of Open Access Journals (Sweden)

    Jamart Jacques

    2010-03-01

    Full Text Available Abstract Background Transcranial direct current stimulation (tDCS is used in human physiological studies and for therapeutic trials in patients with abnormalities of cortical excitability. Its safety profile places tDCS in the pole-position for translating in real-world therapeutic application. However, an episode of transient respiratory depression in a subject receiving tDCS with an extracephalic electrode led to the suggestion that such an electrode montage could modulate the brainstem autonomic centres. We investigated whether tDCS applied over the midline frontal cortex in 30 healthy volunteers (sham n = 10, cathodal n = 10, anodal n = 10 with an extracephalic reference electrode would modulate brainstem activity as reflected by the monitoring and stringent analysis of vital parameters: heart rate (variability, respiratory rate, blood pressure and sympatho-vagal balance. We reasoned that this study could lead to two opposite but equally interesting outcomes: 1 If tDCS with an extracephalic electrode modulated vital parameters, it could be used as a new tool to explore the autonomic nervous system and, even, to modulate its activity for therapeutic purposes. 2 On the opposite, if applying tDCS with an extracephalic electrode had no effect, it could thus be used safely in healthy human subjects. This outcome would significantly impact the field of non-invasive brain stimulation with tDCS. Indeed, on the one hand, using an extracephalic electrode as a genuine neutral reference (as opposed to the classical "bi-cephalic" tDCS montages which deliver bi-polar stimulation of the brain would help to comfort the conclusions of several modern studies regarding the spatial location and polarity of tDCS. On the other hand, using an extracephalic reference electrode may impact differently on a given cortical target due to the change of direct current flow direction; this may enlarge the potential interventions with tDCS. Results Whereas the respiratory

  11. The Effect of a Short-term Glucose Deprivation on Neuron Net Functioning of Hippocampus Primary Culture on a Multi-electrode Matrix

    OpenAIRE

    Vedunova M.V.; Korotchenko S.A.; Balashova A.N.; Isakova A.O.; Khaspekov L.G.; Kazantsev V.B.; Mukhina I.V.

    2011-01-01

    There has been studied the effect of a short-term glucose deprivation on neuron net functioning of hippocampus primary culture developing within 32 days on a multi-electrode matrix MED64 (Alpha MED Sciences Company, Japan) in an early and remote periods after deprivation. A short-term glucose deprivation (20 min) has been shown to result in the increase of electrobiological activity of neuron net of hippocampus primary culture, with the cascade of metabolic reactions being activated leading t...

  12. Sandwich-structured nanohybrid paper based on controllable growth of nanostructured MnO2 on ionic liquid functionalized graphene paper as a flexible supercapacitor electrode.

    Science.gov (United States)

    Sun, Yimin; Fang, Zheng; Wang, Chenxu; Ariyawansha, K R Rakhitha Malinga; Zhou, Aijun; Duan, Hongwei

    2015-05-07

    A sandwich-structured flexible supercapacitor electrode has been developed based on MnO2 nanonest (MNN) modified ionic liquid (IL) functionalized graphene paper (GP), which is fabricated by functionalizing graphene nanosheets with an amine-terminated IL (i.e., 1-(3-aminopropyl)-3-methylimidazolium bromide) to form freestanding IL functionalized GP (IL-GP), and then modifying IL-GP with a unique MNN structure via controllable template-free ultrasonic electrodeposition. The as-obtained MNN modified IL-GP (MNN/IL-GP) inherits the excellent pseudocapacity of the metal oxide, the high conductivity and electric double layer charging/discharging of IL-graphene composites, and therefore shows an enhanced supercapacitor performance. The maximum specific capacitance of 411 F g(-1) can be achieved by chronopotentiometry at a current density of 1 A g(-1). Meanwhile, the MNN/IL-GP electrode exhibits excellent rate capability and cycling stability, its specific capacitance is maintained at 70% as the current densities increase from 1 to 20 A g(-1) and 85% at a current density of 10 A g(-1) after 10 000 cycles. More importantly, the MNN/IL-GP displays distinguished mechanical stability and flexibility for device packaging, although its thickness is merely 8 μm. These features collectively demonstrate the potential of MNN/IL-GP as a high-performance paper electrode for flexible and lightweight and highly efficient electrochemical capacitor applications.

  13. Single-Layer Pentacene Field-Effect Transistors Using Electrodes Modified With Self-assembled Monolayers

    NARCIS (Netherlands)

    Asadi, Kamal; Wu, Yu; Gholamrezaie, Fatemeh; Rudolf, Petra; Blom, Paul W. M.

    2009-01-01

    Pentacene field-effect transistor performance can be improved by modifying metal electrodes with self-assembled monolayers. The dominant role in performance is played by pentacene morphology rather than the work function of the modified electrodes. With optimized processing conditions,

  14. Effects of electrode material and configuration on the characteristics of planar resistive switching devices

    KAUST Repository

    Peng, H.Y.; Pu, L.; Wu, J.C.; Cha, Dong Kyu; Hong, J.H.; Lin, W.N.; Li, Yangyang; Ding, Junfeng; David, A.; Li, K.; Wu, Tao

    2013-01-01

    We report that electrode engineering, particularly tailoring the metal work function, measurement configuration and geometric shape, has significant effects on the bipolar resistive switching (RS) in lateral memory devices based on self-doped SrTiO3

  15. When two worlds collude: working from home and family functioning

    OpenAIRE

    Alfred Michael Dockery; Sherry Bawa

    2015-01-01

    Whether or not working from home or ‘telecommuting’ helps workers to balance work and family commitments, as opposed to providing an avenue for work to intrude on family life remains a contentious issue. On balance it seems the flexibility to work some hours from home is a positive for workers. This was confirmed for a representative sample of Australian employees drawn from the Household, Income and Labour Dynamics in Australia Survey (HILDA) from 2001 to 2011, but with the reservation that ...

  16. Mindfulness, Authentic Functioning, and Work Engagement: A Growth Modeling Approach

    Science.gov (United States)

    Leroy, Hannes; Anseel, Frederik; Dimitrova, Nicoletta G.; Sels, Luc

    2013-01-01

    Previous research has demonstrated that mindfulness helps reduce symptoms of work stress but research has yet to clarify "whether" and "how" mindfulness is linked to work engagement. Using self-determination theory we hypothesize that mindfulness is positively related to work engagement and that this relationship can be better understood through…

  17. Mindfulness, authentic functioning, and work engagement: A growth modeling approach

    NARCIS (Netherlands)

    Leroy, H.; Anseel, F.; Dimitrova, N.G.; Sels, L.

    2013-01-01

    Previous research has demonstrated that mindfulness helps reduce symptoms of work stress but research has yet to clarify whether and how mindfulness is linked to work engagement. Using self-determination theory we hypothesize that mindfulness is positively related to work engagement and that this

  18. Bioethanol in Biofuels Checked by an Amperometric Organic Phase Enzyme Electrode (OPEE Working in “Substrate Antagonism” Format

    Directory of Open Access Journals (Sweden)

    Mauro Tomassetti

    2016-08-01

    Full Text Available The bioethanol content of two samples of biofuels was determined directly, after simple dilution in decane, by means of an amperometric catalase enzyme biosensor working in the organic phase, based on substrate antagonisms format. The results were good from the point of view of accuracy, and satisfactory for what concerns the recovery test by the standard addition method. Limit of detection (LOD was on the order of 2.5 × 10−5 M.

  19. Voltammetry at micro-mesh electrodes

    Directory of Open Access Journals (Sweden)

    Wadhawan Jay D.

    2003-01-01

    Full Text Available The voltammetry at three micro-mesh electrodes is explored. It is found that at sufficiently short experimental durations, the micro-mesh working electrode first behaves as an ensemble of microband electrodes, then follows the behaviour anticipated for an array of diffusion-independent micro-ring electrodes of the same perimeter as individual grid-squares within the mesh. During prolonged electrolysis, the micro-mesh electrode follows that behaviour anticipated theoretically for a cubically-packed partially-blocked electrode. Application of the micro-mesh electrode for the electrochemical determination of carbon dioxide in DMSO electrolyte solutions is further illustrated.

  20. The kinetics of porous insertion electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Atlung, S; West, K [British Columbia Univ., Vancouver (Canada)

    1989-05-01

    The principles of porous electrodes are discussed as well as the discharge of the insertion compound, the working potential, transport in the electrolyte, the time dependence of the electrolyte concentration, and modeling of the porous electrode. The simulation of a TiS2 porous electrode and the composite insertion electrode are considered as well. The influence of electrode thickness and porosity in a typical porous TiS2 electrode is revealed. It is shown that the use of insertion compounds as battery electrodes is limited by the requirement that the inserted ion must be distributed in the interior of the insertion compound particle. 15 refs.

  1. Sensitive and selective determination of Cu2+ at D-penicillamine functionalized nano-cellulose modified pencil graphite electrode

    Science.gov (United States)

    Taheri, M.; Ahour, F.; Keshipour, S.

    2018-06-01

    A novel electrochemical sensor based on D-penicillamine anchored nano-cellulose (DPA-NC) modified pencil graphite electrode was fabricated and used for highly selective and sensitive determination of copper (II) ions in the picomolar concentration by square wave adsorptive stripping voltammetric (SWV) method. The modified electrode showed better and increased SWV response compared to the bare and NC modified electrodes which may be related to the porous structure of modifier along with formation of complex between Cu2+ ions and nitrogen or oxygen containing groups in DPA-NC. Optimization of various experimental parameters influence the performance of the sensor, were investigated. Under optimized condition, DPA-NC modified electrode was used for the analysis of Cu2+ in the concentration range from 0.2 to 50 pM, and a lower detection limit of 0.048 pM with good stability, repeatability, and selectivity. Finally, the practical applicability of DPA-NC-PGE was confirmed via measuring trace amount of Cu (II) in tap and river water samples.

  2. Liquid electrode

    Science.gov (United States)

    Ekechukwu, A.A.

    1994-07-05

    A dropping electrolyte electrode is described for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions. 2 figures.

  3. The Work Role Functioning Questionnaire v2.0 Showed Consistent Factor Structure Across Six Working Samples

    NARCIS (Netherlands)

    Abma, F.I.; Bultmann, U.; Amick III, B.C.; Arends, I.; Dorland, P.A.; Flach, P.A.; Klink, J.J.L van der; Ven H.A., van de; Bjørner, J.B.

    2017-01-01

    Objective The Work Role Functioning Questionnaire v2.0 (WRFQ) is an outcome measure linking a persons’ health to the ability to meet work demands in the twenty-first century. We aimed to examine the construct validity of the WRFQ in a heterogeneous set of working samples in the Netherlands with

  4. The Work Role Functioning Questionnaire v2.0 Showed Consistent Factor Structure Across Six Working Samples

    DEFF Research Database (Denmark)

    Abma, Femke I.; Bültmann, Ute; Amick, Benjamin C.

    2017-01-01

    Objective: The Work Role Functioning Questionnaire v2.0 (WRFQ) is an outcome measure linking a persons’ health to the ability to meet work demands in the twenty-first century. We aimed to examine the construct validity of the WRFQ in a heterogeneous set of working samples in the Netherlands...

  5. Stimulation and recording electrodes for neural prostheses

    CERN Document Server

    Pour Aryan, Naser; Rothermel, Albrecht

    2015-01-01

    This book provides readers with basic principles of the electrochemistry of the electrodes used in modern, implantable neural prostheses. The authors discuss the boundaries and conditions in which the electrodes continue to function properly for long time spans, which are required when designing neural stimulator devices for long-term in vivo applications. Two kinds of electrode materials, titanium nitride and iridium are discussed extensively, both qualitatively and quantitatively. The influence of the counter electrode on the safety margins and electrode lifetime in a two electrode system is explained. Electrode modeling is handled in a final chapter.

  6. The investigation of movement dynamics of an AC electric arc attachment along the working surface of a hollow cylindrical electrode under the action of gas-dynamic and electromagnetic forces

    International Nuclear Information System (INIS)

    Surov, A V; Popov, S D; Serba, E O; Nakonechny, G V; Spodobin, V A; Ovchinnikov, R V; Kumkova, I I; Shabalin, S A

    2012-01-01

    Stationary electric arc alternating current plasma torches are used today for realization of plasma chemical technologies requiring relatively high energy input. Waste treatment is one these directions. The paper reports on experiment results directed towards the increase in the lifetime characteristics of electrode units of the powerful high-voltage electric-arc AC plasma torches. The solution to the problem of obtainment the uniform wear of a copper hollow cylindrical electrode achieved by the controlled movement of the arc attachment along the working surface was offered. Organization of gas supply in the near electrode area and application of alternating magnetic field ensured movement of arc attachment along the surface with average speed from 2 to 14 m/s. Arc current was about 47 A and 84 A, gas flow rate in near electrode area was about 5 and 4.5 g/s. Due to researches on the experimental prototype of a hollow cylindrical electrode, the erosion of its material reached only 3 μg/C, that enables production of the electrode assembly with life time above 1000 hours at currents in the arc up to 100–200 A.

  7. electrode array

    African Journals Online (AJOL)

    PROF EKWUEME

    A geoelectric investigation employing vertical electrical soundings (VES) using the Ajayi - Makinde Two-Electrode array and the ... arrangements used in electrical D.C. resistivity survey. These include ..... Refraction Tomography to Study the.

  8. Transparent Electrodes for Efficient Optoelectronics

    KAUST Repository

    Morales-Masis, Monica

    2017-03-30

    With the development of new generations of optoelectronic devices that combine high performance and novel functionalities (e.g., flexibility/bendability, adaptability, semi or full transparency), several classes of transparent electrodes have been developed in recent years. These range from optimized transparent conductive oxides (TCOs), which are historically the most commonly used transparent electrodes, to new electrodes made from nano- and 2D materials (e.g., metal nanowire networks and graphene), and to hybrid electrodes that integrate TCOs or dielectrics with nanowires, metal grids, or ultrathin metal films. Here, the most relevant transparent electrodes developed to date are introduced, their fundamental properties are described, and their materials are classified according to specific application requirements in high efficiency solar cells and flexible organic light-emitting diodes (OLEDs). This information serves as a guideline for selecting and developing appropriate transparent electrodes according to intended application requirements and functionality.

  9. Transparent Electrodes for Efficient Optoelectronics

    KAUST Repository

    Morales-Masis, Monica; De Wolf, Stefaan; Woods-Robinson, Rachel; Ager, Joel W.; Ballif, Christophe

    2017-01-01

    With the development of new generations of optoelectronic devices that combine high performance and novel functionalities (e.g., flexibility/bendability, adaptability, semi or full transparency), several classes of transparent electrodes have been developed in recent years. These range from optimized transparent conductive oxides (TCOs), which are historically the most commonly used transparent electrodes, to new electrodes made from nano- and 2D materials (e.g., metal nanowire networks and graphene), and to hybrid electrodes that integrate TCOs or dielectrics with nanowires, metal grids, or ultrathin metal films. Here, the most relevant transparent electrodes developed to date are introduced, their fundamental properties are described, and their materials are classified according to specific application requirements in high efficiency solar cells and flexible organic light-emitting diodes (OLEDs). This information serves as a guideline for selecting and developing appropriate transparent electrodes according to intended application requirements and functionality.

  10. Evaluating the performance of graphene with structural defect and functionalized by –C6H4 as an electrode active material for supercapacitors

    Directory of Open Access Journals (Sweden)

    S M Mousavi-Khoshdel

    2017-02-01

    Full Text Available In this study, quantum capacitance of graphene-based electrodes is evaluated using Density Functional Theory (DFT calculations. The obtained results showed that quantum capacitance of graphene-based supercapacitors could be significantly improved by existence of structural defects on the graphene sheets at sufficiently high concentrations because of creating impure states resulted from carbon pz orbitals involved in defect. In another section of calculations, quantum capacitance of functionalized graphene with –C6H4, is evaluated. The obtained results of calculations showed that functionalized graphene with this functional group have a very good capacitance in comparison with pristine graphene, especially at smaller voltages of less than -1.0 V or greater than 1.0 V. Hybrid configurations between structural defects and functional group of –C6H4 was also studied. In general, the results indicated that the combined configuration shows higher capacity than pristine graphene

  11. The Role of Work Function and Band Gap in Resistive Switching Behaviour of ZnTe Thin Films

    Science.gov (United States)

    Rowtu, Srinu; Sangani, L. D. Varma; Krishna, M. Ghanashyam

    2018-02-01

    Resistive switching behavior by engineering the electrode work function and band gap of ZnTe thin films is demonstrated. The device structures Au/ZnTe/Au, Au/ZnTe/Ag, Al/ZnTe/Ag and Pt/ZnTe/Ag were fabricated. ZnTe was deposited by thermal evaporation and the stoichiometry and band gap were controlled by varying the source-substrate distance. Band gap could be varied between 1.0 eV to approximately 4.0 eV with the larger band gap being attributed to the partial oxidation of ZnTe. The transport characteristics reveal that the low-resistance state is ohmic in nature which makes a transition to Poole-Frenkel defect-mediated conductivity in the high-resistance states. The highest R off-to- R on ratio achieved is 109. Interestingly, depending on stoichiometry, both unipolar and bipolar switching can be realized.

  12. Development of a modified electrode with amine-functionalized TiO{sub 2}/multi-walled carbon nanotubes nanocomposite for electrochemical sensing of the atypical neuroleptic drug olanzapine

    Energy Technology Data Exchange (ETDEWEB)

    Arvand, Majid, E-mail: arvand@guilan.ac.ir; Palizkar, Bahareh

    2013-12-01

    In this work, using of amine-functionalized TiO{sub 2}/multi-walled carbon nanotubes (NH{sub 2}-TiO{sub 2}-MWCNTs) nanocomposite for modification of glassy carbon electrode (GCE) was investigated. The nanocomposite was characterized by Fourier transformed infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. The efficiency of modified electrode for electrocatalytic the oxidation of olanzapine was studied by cyclic voltammetry, square wave voltammetry and chronoamperometry. The electrochemical measurements were carried out in phosphate-buffered solution (PBS, pH 5.0). The NH{sub 2}-TiO{sub 2}-MWCNTs/GCE provided high surface area and more sensitive performance. The charge transfer coefficient (α) and the apparent charge transfer rate constant (k{sub s}) were calculated to be equal to 0.42 and 0.173 s{sup −1}, respectively. The square wave voltammetry exhibited two linear dynamic ranges and a detection limit of 0.09 μM of olanzapine. In addition, the modified electrode was employed for the determination of olanzapine in pharmaceutical and human blood serum samples in order to illustrate the applicability of proposed method. - Highlights: • A simple and rapid sensor for determination of olanzapine in tablet and serum was prepared. • The amine-functionalized TiO{sub 2}-MWCNTs/GCE showed an obvious increase in surface area. • The presence of NH{sub 2}-TiO{sub 2} nanoparticles showed good ability to distinguish the response of olanzapine.

  13. Research and development of tungsten electrodes added with rare earth oxides

    International Nuclear Information System (INIS)

    Zuoren Nie; Ying Chen; Meiling Zhou; Tieyong Zuo

    2001-01-01

    The recent research and development of tungsten electrodes used in TIG and Plasma technologies are introduced, and the tungsten materials as well as the effects of rare earth oxides are specially discussed. in W-La 2 O 3 , W-CeO 2 , W-Y 2 O 3 and W-ThO 2 electrode materials, the W-2.2mass%La 2 O 3 electrode exhibited the best properties when the current is of little or middle volume, and when the electrodes are used in large current, the W-Y 2 O 3 electrode is the best. By a comparative study between the tungsten electrodes activated with single metal oxides, as above-mentioned, and those containing two or three rare earth oxides, namely La 2 O 3 , CeO 2 and Y 2 O 3 , it was indicated that the welding arc properties of the tungsten electrodes activated with combined rare earth oxides additions is superior than that of the electrodes containing single oxides as above mentioned. It was also shown that the operating properties of tungsten electrodes depend intensively on the rare earth oxides contained in the electrodes, and the actions of rare earth oxides during arcing are the most important factors to the electrodes' operating properties, temperature, work function as well as the arc stability. (author)

  14. Study of the interaction of 6-mercaptopurine with protein by microdialysis coupled with LC and electrochemical detection based on functionalized multi-wall carbon nanotubes modified electrode.

    Science.gov (United States)

    Cao, Xu-Ni; Lin, Li; Zhou, Yu-Yan; Zhang, Wen; Shi, Guo-Yue; Yamamoto, Katsunobu; Jin, Li-Tong

    2003-07-14

    Microdialysis sampling coupled with liquid chromatography and electrochemical detection (LC-ECD) was developed and applied to study the interaction of 6-Mercaptopurine (6-MP) with bovine serum albumin (BSA). In the LC-ECD, the multi-wall carbon nanotubes fuctionalized with carboxylic groups modified electrode (MWNT-COOH CME) was used as the working electrode for the determination of 6-MP. The results indicated that this chemically modified electrode (CME) exhibited efficiently electrocatalytic oxidation for 6-MP with relatively high sensitivity, stability and long-life. The peak currents of 6-MP were linear to its concentrations ranging from 4.0 x 10(-7) to 1.0 x 10(-4) mol l(-1) with the calculated detection limit (S/N = 3) of 2.0 x 10(-7) mol l(-1). The method had been successfully applied to assess the association constant (K) and the number of the binding sites (n) on a BSA molecular, which calculated by Scatchard equation, were 3.97 x 10(3) mol(-1) l and 1.51, respectively. This method provided a fast, sensible and simple technique for the study of drug-protein interactions.

  15. Strain effects on the work function of an organic semiconductor

    KAUST Repository

    Wu, Yanfei; Chew, Annabel R.; Rojas, Geoffrey A.; Sini, Gjergji; Haugstad, Greg; Belianinov, Alex; Kalinin, Sergei V.; Li, Hong; Risko, Chad; Bredas, Jean-Luc; Salleo, Alberto; Frisbie, C. Daniel

    2016-01-01

    by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional

  16. Bibliographic update work. Dental pulp sensory function. Pain.

    OpenAIRE

    Gomez, Natanael

    2011-01-01

    Dental pulp is a soft connective tissue type that thanks to its components can fulfill a number of vital functions to the tooth. Within these, the sensory function is of great interest since there is a close relationship between histomolecular tissue changes and clinical manifestations of odontogenic pain. To think about the painful history that the patient reports, knowing the tissue level events, helps to arrive to a correct diagnosis, treatment plan and prognosis. The aim of thi...

  17. Working memory training in congenitally blind individuals results in an integration of occipital cortex in functional networks.

    Science.gov (United States)

    Gudi-Mindermann, Helene; Rimmele, Johanna M; Nolte, Guido; Bruns, Patrick; Engel, Andreas K; Röder, Brigitte

    2018-08-01

    The functional relevance of crossmodal activation (e.g. auditory activation of occipital brain regions) in congenitally blind individuals is still not fully understood. The present study tested whether the occipital cortex of blind individuals is integrated into a challenged functional network. A working memory (WM) training over four sessions was implemented. Congenitally blind and matched sighted participants were adaptively trained with an n-back task employing either voices (auditory training) or tactile stimuli (tactile training). In addition, a minimally demanding 1-back task served as an active control condition. Power and functional connectivity of EEG activity evolving during the maintenance period of an auditory 2-back task were analyzed, run prior to and after the WM training. Modality-specific (following auditory training) and modality-independent WM training effects (following both auditory and tactile training) were assessed. Improvements in auditory WM were observed in all groups, and blind and sighted individuals did not differ in training gains. Auditory and tactile training of sighted participants led, relative to the active control group, to an increase in fronto-parietal theta-band power, suggesting a training-induced strengthening of the existing modality-independent WM network. No power effects were observed in the blind. Rather, after auditory training the blind showed a decrease in theta-band connectivity between central, parietal, and occipital electrodes compared to the blind tactile training and active control groups. Furthermore, in the blind auditory training increased beta-band connectivity between fronto-parietal, central and occipital electrodes. In the congenitally blind, these findings suggest a stronger integration of occipital areas into the auditory WM network. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. The impact of precancerous cervical lesions on functioning at work and work productivity.

    Science.gov (United States)

    Lerner, Debra; Parsons, Susan K; Justicia-Linde, Faye; Chelmow, David; Chang, Hong; Rogers, William H; Greenhill, Annabel M; Perch, Katherine; Kruzikas, Denise

    2010-09-01

    To assess the work performance and productivity impact of human papillomavirus (HPV). A cross-sectional study compared 94 employed women with clinically significant HPV-related cervical lesions with 118 healthy controls. Data were collected by self-administered web-based questionnaire. At-work performance limitations and productivity loss (presenteeism) and absenteeism were measured. Univariate and multivariate case-control group and clinical subgroup differences were tested. Based on adjusted mean scores, the HPV group had significantly more at-work limitations and productivity loss than controls (P = 0.009), higher absence rates (P = 0.002), and significantly more productivity loss because of absences (P = 0.007). At-work limitations varied in association with martial status (P = 0.025); at-work productivity loss was associated with years of education (P = 0.039). HPV is costly for working women, their employers, and the economy.

  19. Functional work breaks in a high-demanding work environment: an experimental field study.

    Science.gov (United States)

    Scholz, André; Ghadiri, Argang; Singh, Usha; Wendsche, Johannes; Peters, Theo; Schneider, Stefan

    2018-02-01

    Work breaks are known to have positive effects on employees' health, performance and safety. Using a sample of twelve employees working in a stressful and cognitively demanding working environment, this experimental field study examined how different types of work breaks (boxing, deep relaxation and usual breaks) affect participants' mood, cognitive performance and neurophysiological state compared to a control condition without any break. In a repeated measures experimental design, cognitive performance was assessed using an auditory oddball test and a Movement Detection Test. Brain cortical activity was recorded using electroencephalography. Individual's mood was analysed using a profile of mood state. Although neurophysiological data showed improved relaxation of cortical state after boxing (vs. 'no break' and 'deep relaxation'), neither performance nor mood assessment showed similar results. It remains questionable whether there is a universal work break type that has beneficial effects for all individuals. Practitioner Summary: Research on work breaks and their positive effects on employees' health and performance often disregards break activities. This experimental field study in a stressful working environment investigated the effect of different work break activities. A universal work break type that is beneficial for this workplace could not be identified.

  20. Momentary Work Happiness as a Function of Enduring Burnout and Work Engagement.

    Science.gov (United States)

    Bakker, Arnold B; Oerlemans, Wido G M

    2016-08-17

    The present study (N = 136) combined global measures with specific, experience-based measures to investigate how enduring job burnout and engagement influence the impact of daily work activities on momentary need satisfaction and happiness. We used the day reconstruction method (DRM) to ask employees from various occupations to reconstruct their working days. On the basis of employee work engagement and self-determination theories, we hypothesized that time spent on (a) core work tasks; (b) administrative work tasks; (c) client interactions; (d) interactions with colleagues; and (e) meetings would be negatively related to need satisfaction on the task level for employees high (vs. low) in enduring burnout; and positively related to need satisfaction on the task level for employees high (vs. low) in enduring work engagement. In addition, we predicted that psychological need satisfaction would mediate the relationships between time spent on work tasks and happiness during the tasks. The results of multilevel analyses largely supported these hypotheses. Our findings contribute to the literature by showing how those with high levels of burnout do not manage to satisfy their basic needs through their work, whereas those with high levels of work engagement satisfy their daily needs and stay happy.

  1. Work Functioning Among Firefighters: A Comparison Between Self-Reported Limitations and Functional Task Performance.

    Science.gov (United States)

    MacDermid, Joy C; Tang, Kenneth; Sinden, Kathryn E; D'Amico, Robert

    2018-05-25

    Purpose Performance-based and disease indicators have been widely studied in firefighters; self-reported work role limitations have not. The aim of this study was to describe the distributions and correlations of a generic self-reported Work Limitations Questionnaire (WLQ-26) and firefighting-specific task performance-based tests. Methods Active firefighters from the City of Hamilton Fire Services (n = 293) were recruited. Participants completed the WLQ-26 to quantify on-the-job difficulties over five work domains: work scheduling (4 items), output demands (7 items), physical demands (8 items), mental demands (4 items), and social demands (3 items). A subset of participants (n = 149) were also assessed on hose drag and stair climb with a high-rise pack performance-based tests. Descriptive statistics and correlations were used to compare item/subscale performance; and to describe the inter-relationships between tests. Results The mean WLQ-26 item scores (/5) ranged from 4.1 to 4.4 (median = 5 for all items); most firefighters (54.5-80.5%) selected "difficult none of the time" response option on all items. A substantial ceiling effect was observed across all five WLQ-26 subscales as 44.0-55.6% were in the highest category. Subscale means ranged from 61.8 (social demands) to 78.7 (output demands and physical demands). Internal consistency exceeded 0.90 on all subscales. For the hose drag task, the mean time-to-completion was 48.0 s (SD = 14.5; range 20.4-95.0). For the stair climb task, the mean time-to-completion was 76.7 s (SD = 37.2; range 21.0-218.0). There were no significant correlations between self-report work limitations and performance of firefighting tasks. Conclusions The WLQ-26 measured five domains, but had ceiling effects in firefighters. Performance-based testing showed wider score range, lacked ceiling effects and did not correlate to the WLQ-26. A firefighter-specific, self-report role functioning scale may be needed to identify

  2. Amorphous transparent conducting oxides in context: Work function survey, trends, and facile modification

    Science.gov (United States)

    Yeh, T. C.; Zhu, Q.; Buchholz, D. B.; Martinson, A. B.; Chang, R. P. H.; Mason, T. O.

    2015-03-01

    The work functions of various amorphous and crystalline transparent conducting oxides (TCOs) were measured using Kelvin probe. The films, made by pulsed laser deposition, exhibited varying work functions dependent on the composition and deposition parameters. Tin oxide showed the largest work functions of the oxides measured, while zinc oxide showed the lowest. Binary and ternary combinations of the basis TCOs showed intermediate work functions dependent on the endpoint components. Amorphous TCOs, important in OPV and other technological applications, exhibited similar work functions to their crystalline counterparts. UV/ozone treatment of TCOs temporarily increased the work function, consistent with proposed defect mechanisms associated with near-surface changes in carrier content and Fermi level. Finally, a method for facile adjustment of the work function of commercial TCOs by atomic layer deposition (ALD) capping layers was presented, illustrated by the growth of zinc oxide layers on commercial crystalline ITO films.

  3. Beyond Conflict: Functional Facets of the Work-Family Interplay

    Science.gov (United States)

    Wiese, Bettina S.; Seiger, Christine P.; Schmid, Christian M.; Freund, Alexandra M.

    2010-01-01

    The present paper deals with three positive facets of the work-family interplay, i.e., transfer of competencies, transfer of positive mood, and cross-domain compensation. The latter refers to the experience that engagement in one domain helps dealing with failures in the other domain. In two correlational studies (N[subscript 1] = 107 working…

  4. Executive Functions as Moderators of the Worked Example Effect: When Shifting Is More Important than Working Memory Capacity

    Science.gov (United States)

    Schwaighofer, Matthias; Bühner, Markus; Fischer, Frank

    2016-01-01

    Worked examples have proven to be effective for knowledge acquisition compared with problem solving, particularly when prior knowledge is low (e.g., Kalyuga, 2007). However, in addition to prior knowledge, executive functions and fluid intelligence might be potential moderators of the effectiveness of worked examples. The present study examines…

  5. Functional Competencies for Adapting to the World of Work.

    Science.gov (United States)

    Selz, Nina; And Others

    A study was conducted to determine who has the responsibility for teaching general occupational and consumer competencies--the home, the school, or the workplace. To answer this question, two national surveys on functional competencies in occupational adaptability and consumer economics were conducted. Competencies were first identified and then…

  6. Cermet electrode

    Science.gov (United States)

    Maskalick, Nicholas J.

    1988-08-30

    Disclosed is a cermet electrode consisting of metal particles of nickel, cobalt, iron, or alloys or mixtures thereof immobilized by zirconia stabilized in cubic form which contains discrete deposits of about 0.1 to about 5% by weight of praseodymium, dysprosium, terbium, or a mixture thereof. The solid oxide electrode can be made by covering a substrate with particles of nickel, cobalt, iron, or mixtures thereof, growing a stabilized zirconia solid oxide skeleton around the particles thereby immobilizing them, contacting the skeleton with a compound of praseodymium, dysprosium, terbium, or a mixture thereof, and heating the skeleton to a temperature of at least 500.degree. C. The electrode can also be made by preparing a slurry of nickel, cobalt, iron, or mixture and a compound of praseodymium, dysprosium, terbium, or a mixture thereof, depositing the slurry on a substrate, heating the slurry to dryness, and growing a stabilized zirconia skeleton around the metal particles.

  7. Engineering the work function of armchair graphene nanoribbons using strain and functional species: a first principles study

    International Nuclear Information System (INIS)

    Peng Xihong; Tang Fu; Copple, Andrew

    2012-01-01

    First principles density functional theory calculations were performed to study the effects of strain, edge passivation, and surface functional species on the structural and electronic properties of armchair graphene nanoribbons (AGNRs), with a particular focus on the work function. The work function was found to increase with uniaxial tensile strain and decrease with compression. The variation of the work function under strain is primarily due to the shift of the Fermi energy with strain. In addition, the relationship between the work function variation and the core level shift with strain is discussed. Distinct trends of the core level shift under tensile and compressive strain were discovered. For AGNRs with the edge carbon atoms passivated by oxygen, the work function is higher than for nanoribbons with the edge passivated by hydrogen under a moderate strain. The difference between the work functions in these two edge passivations is enlarged (reduced) under a sufficient tensile (compressive) strain. This has been correlated to a direct-indirect bandgap transition for tensile strains of about 4% and to a structural transformation for large compressive strains at about - 12%. Furthermore, the effect of the surface species decoration, such as H, F, or OH with different covering density, was investigated. It was found that the work function varies with the type and coverage of surface functional species. Decoration with F and OH increases the work function while H decreases it. The surface functional species were decorated on either one side or both sides of AGNRs. The difference in the work functions between one-sided and two-sided decorations was found to be relatively small, which may suggest an introduced surface dipole plays a minor role. (paper)

  8. Electrochemical detection of copper ions leached from CuO nanoparticles in saline buffers and biological media using a gold wire working electrode

    Energy Technology Data Exchange (ETDEWEB)

    Baldisserri, Carlo, E-mail: carlo.baldisserri@istec.cnr.it; Costa, Anna Luisa [ISTEC-CNR (Italy)

    2016-04-15

    We performed explorative cyclic voltammetry in phosphate-buffered saline buffers, Dulbecco’s modified Eagle’s medium (DMEM), and fetal bovine serum-added DMEM using Au wire as working electrode, both in the absence and in the presence of known nominal concentrations of Cu{sup 2+} ions or 15 nm CuO nanoparticles. Addition of either Cu{sup 2+} ions or aqueous suspension of CuO nanoparticles caused a single anodic peak to appear in the double-layer region of all three pristine media. The height of the anodic peak was found to increase in a monotonic fashion vs. Cu{sup 2+} concentration in Cu{sup 2+}-added media, and versus time since CuO addition in CuO-added media. Stepwise addition of glycine to Cu{sup 2+}-added phosphate-buffered saline buffer caused an increasing cathodic shift of the anodic peak accompanied by decreasing peak currents. Results indicate that preparing Cu{sup 2+}-free suspensions of CuO nanoparticles in such media is difficult, owing to the presence of leached copper ions. The implications on results of experiments in which CuO nanoparticle-added biological media are used as cell culture substrates are discussed. Literature data on the interactions between Cu{sup 2+} ions, dissolved carbon dioxide in aqueous CuO suspensions, and amino acids present in such media are compared to our results.

  9. Electrochemical detection of copper ions leached from CuO nanoparticles in saline buffers and biological media using a gold wire working electrode

    Science.gov (United States)

    Baldisserri, Carlo; Costa, Anna Luisa

    2016-04-01

    We performed explorative cyclic voltammetry in phosphate-buffered saline buffers, Dulbecco's modified Eagle's medium (DMEM), and fetal bovine serum-added DMEM using Au wire as working electrode, both in the absence and in the presence of known nominal concentrations of Cu2+ ions or 15 nm CuO nanoparticles. Addition of either Cu2+ ions or aqueous suspension of CuO nanoparticles caused a single anodic peak to appear in the double-layer region of all three pristine media. The height of the anodic peak was found to increase in a monotonic fashion vs. Cu2+ concentration in Cu2+-added media, and versus time since CuO addition in CuO-added media. Stepwise addition of glycine to Cu2+-added phosphate-buffered saline buffer caused an increasing cathodic shift of the anodic peak accompanied by decreasing peak currents. Results indicate that preparing Cu2+-free suspensions of CuO nanoparticles in such media is difficult, owing to the presence of leached copper ions. The implications on results of experiments in which CuO nanoparticle-added biological media are used as cell culture substrates are discussed. Literature data on the interactions between Cu2+ ions, dissolved carbon dioxide in aqueous CuO suspensions, and amino acids present in such media are compared to our results.

  10. 20 CFR 220.126 - Relationship of ability to do work and residual functional capacity.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Relationship of ability to do work and... Relationship of ability to do work and residual functional capacity. (a) If the claimant can do his or her previous work (his or her usual work or other applicable past work), the Board will determine he or she is...

  11. Functional heterogeneity within Broca's area during verbal working memory.

    Science.gov (United States)

    Chein, J M; Fissell, K; Jacobs, S; Fiez, J A

    2002-12-01

    In previous fMRI research, we found that two subregions of the left inferior frontal cortex showed distinct patterns of activity during a verbal working memory task. Specifically, a more dorsal region tracked with performance, while a more ventral region was sensitive to lexical status. To test the veracity of this finding, we developed a new method for meta-analysis of neuroimaging results. In this method, Gaussian probability distributions are formed around stereotaxic coordinates obtained from published neuroimaging studies. These probability distributions are then combined to identify regions of convergence across studies. When this method was applied to prior studies of working memory, the results largely paralleled those from earlier reviews of the literature on working memory, but also confirmed our empirical findings showing distinct foci within Broca's area. Further application of this meta-analytic technique substantiated the dissociation in these regions for performance and sublexical processing. These results help to validate a novel approach for meta-analysis of neuroimaging findings that avoids many of the subjective assumptions involved in alternative approaches.

  12. Brain injury impairs working memory and prefrontal circuit function

    Directory of Open Access Journals (Sweden)

    Colin James Smith

    2015-11-01

    Full Text Available More than 2.5 million Americans suffer a traumatic brain injury (TBI each year. Even mild to moderate traumatic brain injury causes long-lasting neurological effects. Despite its prevalence, no therapy currently exists to treat the underlying cause of cognitive impairment suffered by TBI patients. Following lateral fluid percussion injury (LFPI, the most widely used experimental model of TBI, we investigated alterations in working memory and excitatory/inhibitory synaptic balance in the prefrontal cortex. LFPI impaired working memory as assessed with a T-maze behavioral task. Field excitatory postsynaptic potentials recorded in the prefrontal cortex were reduced in slices derived from brain-injured mice. Spontaneous and miniature excitatory postsynaptic currents onto layer 2/3 neurons were more frequent in slices derived from LFPI mice while inhibitory currents onto layer 2/3 neurons were smaller after LFPI. Additionally, an increase in action potential threshold and concomitant decrease in firing rate was observed in layer 2/3 neurons in slices from injured animals. Conversely, no differences in excitatory or inhibitory synaptic transmission onto layer 5 neurons were observed; however, layer 5 neurons demonstrated a decrease in input resistance and action potential duration after LFPI. These results demonstrate synaptic and intrinsic alterations in prefrontal circuitry that may underlie working memory impairment caused by TBI.

  13. Study on surface defect structures of ZrO2 and some doped ZrO2 by means of work function measurement

    International Nuclear Information System (INIS)

    Yamawaki, M.; Suzuki, A.; Ono, F.; Yamaguchi, K.

    1997-01-01

    The work function change of the ZrO 2 +2%Y 2 O 3 sintered pellet, caused by a change of the composition of the sweep gas, was measured using a high temperature Kelvin probe. The Pt reference electrode was calibrated by using ZrO 2 +2%Y 2 O 3 as a standard material. Work function changes of undoped ZrO 2 and Nb-doped ZrO 2 (2%Nb 2 O 5 ) were measured as a function of equilibrium oxygen partial pressure, P O 2 . The thus obtained exponents of P O 2 , 1/n, were 1/6.2 and 1/33.6 for ZrO 2 and ZrO 2 +2%Nb 2 O 5 , respectively. These exponent values were discussed in terms of defect chemistry of the surface layer. (orig.)

  14. Single Electrode Heat Effects

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Broers, G. H. J.

    1977-01-01

    The heat evolution at a single irreversibly working electrode is treated onthe basis of the Brønsted heat principle. The resulting equation is analogous to the expression for the total heat evolution in a galvanic cellwith the exception that –DeltaS is substituted by the Peltier entropy, Delta......SP, of theelectrode reaction. eta is the overvoltage at the electrode. This equation is appliedto a high temperature carbonate fuel cell. It is shown that the Peltier entropyterm by far exceeds the heat production due to the irreversible losses, and thatthe main part of heat evolved at the cathode is reabsorbed...

  15. Mixtures of functionalized aromatic groups generated from diazonium chemistry as templates towards bimetallic species supported on carbon electrode surfaces

    International Nuclear Information System (INIS)

    Vilà, Neus; Bélanger, Daniel

    2012-01-01

    Mixtures of 4-sulfophenyl and 4-aminophenyl groups were grafted onto carbon electrodes by electrochemical reduction of their corresponding diazonium cations. Two experimental methodologies were tested in order to control primarily the composition of the binary organic films and subsequently the composition of the bimetallic Cu/Pt layers. The composition of the organic layers was controlled either by changing the ratio of the two components in solution and applying a cathodic potential at which both diazonium cations are electrochemically reduced. The organic layers were characterized by cyclic voltammetry, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy. These binary organic films were subsequently used as templates to load bimetallic species to the carbon surface based on electrostatic interactions of 4-sulfophenyl and 4-aminophenyl groups with Cu 2+ and PtCl 6 2− ionic species dissolved in solution, respectively. The metal complexes, electrostatically bounded to the ionic sites of the grafted groups, were reduced by using NaBH 4 as reducing agent. The amount of Cu was estimated by stripping voltammetry in a sulfuric acid aqueous solution whereas adsorption/desorption of hydrogen was used to quantify the platinum present on the carbon surface. XPS analysis of the metallic surfaces was also performed to confirm the presence of the metals on the electrode surface. The results indicate that the composition of the bimetallic layers is controlled by the ratio of the 4-sulfophenyl and 4-aminophenyl grafted groups.

  16. Predictors of impaired work functioning in employees with major depression in remission

    NARCIS (Netherlands)

    de Vries, Gabe; Koeter, Maarten W. J.; Nieuwenhuijsen, Karen; Hees, Hiske L.; Schene, Aart H.

    2015-01-01

    This study aims to (i) assess work functioning in employees returning to work with a major depression in remission, (ii) study the predictors of impaired work functioning. Participants diagnosed with major depressive disorder (MDD), on long term sick leave (mean 27 weeks) and treated in a

  17. Predictors of impaired work functioning in employees with major depression in remission

    NARCIS (Netherlands)

    Vries, G. de; Koeter, M.W.; Nieuwenhuijsen, K.; Hees, H.L.; Schene, A.H.

    2015-01-01

    OBJECTIVES: This study aims to (i) assess work functioning in employees returning to work with a major depression in remission, (ii) study the predictors of impaired work functioning. METHODS: Participants diagnosed with major depressive disorder (MDD), on long term sick leave (mean 27 weeks) and

  18. Work functioning in persons with depressive and anxiety disorders: The role of specific psychopathological characteristics

    NARCIS (Netherlands)

    Plaisier, I.; Beekman, A.T.F.; De Graaf, R.; Smit, J.H.; van Dyck, R.; Penninx, B.W.J.H.

    2010-01-01

    Background: Depressive and anxiety disorders affect work functioning and cause high labour costs. Aims: To examine and compare psychopathological characteristics of depressive and anxiety disorders in their effect on work functioning. Method: In 1876 working participants of the Netherlands Study of

  19. Robust high temperature oxygen sensor electrodes

    DEFF Research Database (Denmark)

    Lund, Anders

    Platinum is the most widely used material in high temperature oxygen sensor electrodes. However, platinum is expensive and the platinum electrode may, under certain conditions, suffer from poisoning, which is detrimental for an oxygen sensor. The objective of this thesis is to evaluate electrode...... materials as candidates for robust oxygen sensor electrodes. The present work focuses on characterising the electrochemical properties of a few electrode materials to understand which oxygen electrode processes are limiting for the response time of the sensor electrode. Three types of porous platinum......-Dansensor. The electrochemical properties of the electrodes were characterised by electrochemical impedance spectroscopy (EIS), and the structures were characterised by x-ray diffraction and electron microscopy. At an oxygen partial pressures of 0.2 bar, the response time of the sensor electrode was determined by oxygen...

  20. Magnetohydrodynamic electrode

    International Nuclear Information System (INIS)

    1980-01-01

    The object of the invention is the provision of a material capable of withstanding a high-temperature, corrosive and erosive environment for use as a ceramic-metal composite electrode current collector in the channel of a magnetohydrodynamic generator. (U.K.)

  1. Introducing trimming and function ranking to Solid Works based on function analysis

    NARCIS (Netherlands)

    Chechurin, Leonid S.; Wits, Wessel Willems; Bakker, Hans M.; Cascini, G.; Vaneker, Thomas H.J.

    2011-01-01

    TRIZ based Function Analysis models existing products based on functional interactions between product parts. Such a function model description is the ideal starting point for product innovation. Design engineers can apply (TRIZ) methods such as trimming and function ranking to this function model

  2. Introducing Trimming and Function Ranking to SolidWorks based on Function Analysis

    NARCIS (Netherlands)

    Chechurin, L.S.; Wits, Wessel Willems; Bakker, Hans M.; Vaneker, Thomas H.J.

    2015-01-01

    TRIZ based Function Analysis models existing products based on functional interactions between product parts. Such a function model description is the ideal starting point for product innovation. Design engineers can apply (TRIZ) methods such as trimming and function ranking to this function model

  3. [Functional mapping using subdural electrodes combined with monitoring during awake craniotomy enabled preservation of function and extensive resection of a glioma adjacent to the parietal lobe language sites: a case report].

    Science.gov (United States)

    Takebayashi, Kento; Saito, Taiichi; Nitta, Masayuki; Tamura, Manabu; Maruyama, Takashi; Muragaki, Yoshihiro; Okada, Yoshikazu

    2015-01-01

    Surgical resection of gliomas located in the dominant parietal lobe is difficult because this lesion is surrounded by multiple functional areas. Although functional mapping during awake craniotomy is very useful for resection of gliomas adjacent to eloquent areas, the limited time available makes it difficult to sufficiently evaluate multiple functions, such as language, calculative ability, distinction of right and left sides, and finger recognition. Here, we report a case of anaplastic oligodendroglioma, which was successfully treated with a combination of functional mapping using subdural electrodes and monitoring under awake craniotomy for glioma. A 32-year-old man presented with generalized seizure. Magnetic resonance imaging revealed a non-enhanced tumor in the left angular and supramarginal gyri. In addition, the tumor showed high accumulation on 11C-methionine positron emission tomography(PET)(tumor/normal brain tissue ratio=3.20). Preparatory mapping using subdural electrodes showed absence of brain function on the tumor lesion. Surgical removal was performed using cortical mapping during awake craniotomy with an updated navigation system using intraoperative magnetic resonance imaging(MRI). The tumor was resected until aphasia was detected by functional monitoring, and the extent of tumor resection was 93%. The patient showed transient transcortical aphasia and Gerstmann's syndrome after surgery but eventually recovered. The pathological diagnosis was anaplastic oligodendroglioma, and the patient was administered chemo-radiotherapy. The patient has been progression free for more than 2 years. The combination of subdural electrode mapping and monitoring during awake craniotomy is useful in order to achieve preservation of function and extensive resection for gliomas in the dominant parietal lobe.

  4. Momentary work happiness as a function of enduring burnout and work engagement

    NARCIS (Netherlands)

    Bakker, A.B.; Oerlemans, W.G.M.

    2016-01-01

    The present study (N = 136) combined global measures with specific, experience-based measures to investigate how enduring job burnout and engagement influence the impact of daily work activities on momentary need satisfaction and happiness. We used the day reconstruction method (DRM) to ask

  5. Improvements and artifact analysis in conductivity images using multiple internal electrodes

    International Nuclear Information System (INIS)

    Farooq, Adnan; McEwan, Alistair Lee; Woo, Eung Je; Oh, Tong In; Tehrani, Joubin Nasehi

    2014-01-01

    Electrical impedance tomography is an attractive functional imaging method. It is currently limited in resolution and sensitivity due to the complexity of the inverse problem and the safety limits of introducing current. Recently, internal electrodes have been proposed for some clinical situations such as intensive care or RF ablation. This paper addresses the research question related to the benefit of one or more internal electrodes usage since these are invasive. Internal electrodes would be able to reduce the effect of insulating boundaries such as fat and bone and provide improved internal sensitivity. We found there was a measurable benefit with increased numbers of internal electrodes in saline tanks of a cylindrical and complex shape with up to two insulating boundary gel layers modeling fat and muscle. The internal electrodes provide increased sensitivity to internal changes, thereby increasing the amplitude response and improving resolution. However, they also present an additional challenge of increasing sensitivity to position and modeling errors. In comparison with previous work that used point sources for the internal electrodes, we found that it is important to use a detailed mesh of the internal electrodes with these voxels assigned to the conductivity of the internal electrode and its associated holder. A study of different internal electrode materials found that it is optimal to use a conductivity similar to the background. In the tank with a complex shape, the additional internal electrodes provided more robustness in a ventilation model of the lungs via air filled balloons. (paper)

  6. Electron work function-a promising guiding parameter for material design.

    Science.gov (United States)

    Lu, Hao; Liu, Ziran; Yan, Xianguo; Li, Dongyang; Parent, Leo; Tian, Harry

    2016-04-14

    Using nickel added X70 steel as a sample material, we demonstrate that electron work function (EWF), which largely reflects the electron behavior of materials, could be used as a guide parameter for material modification or design. Adding Ni having a higher electron work function to X70 steel brings more "free" electrons to the steel, leading to increased overall work function, accompanied with enhanced e(-)-nuclei interactions or higher atomic bond strength. Young's modulus and hardness increase correspondingly. However, the free electron density and work function decrease as the Ni content is continuously increased, accompanied with the formation of a second phase, FeNi3, which is softer with a lower work function. The decrease in the overall work function corresponds to deterioration of the mechanical strength of the steel. It is expected that EWF, a simple but fundamental parameter, may lead to new methodologies or supplementary approaches for metallic materials design or tailoring on a feasible electronic base.

  7. Anisotropy of electron work function and reticular compacting of friable faces of metallic crystals

    International Nuclear Information System (INIS)

    Vladimirov, A.F.

    1999-01-01

    The review and statistical estimate of experimental data on work functions for BCC-, FCC- and HCP - metals (W, Mo, Ta, Nb, Cr, V, Ni, Y) as well as the earlier developed quantum-mechanical statistical model of double electrical layer formation at metal surface and the calculation of an electron work function dipole constituent serve as a basis for the development of a semi-empirical theory of electron work function anisotropy. A coefficient of reticular compacting of friable crystal faces is introduced and statistically estimated. A coefficient of crystal emission anisotropy is also introduced and estimated both theoretically and empirically. The theory permits calculating work functions for all crystal faces and a volumetric constituent of the work function from the measured value of electron work function for a single face [ru

  8. Variations in erosive wear of metallic materials with temperature via the electron work function

    International Nuclear Information System (INIS)

    Huang, Xiaochen; Yu, Bin; Yan, X.G.; Li, D.Y.

    2016-01-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  9. Predictors of impaired work functioning in employees with major depression in remission.

    Science.gov (United States)

    de Vries, Gabe; Koeter, Maarten W J; Nieuwenhuijsen, Karen; Hees, Hiske L; Schene, Aart H

    2015-10-01

    This study aims to (i) assess work functioning in employees returning to work with a major depression in remission, (ii) study the predictors of impaired work functioning. Participants diagnosed with major depressive disorder (MDD), on long term sick leave (mean 27 weeks) and treated in a specialized mental healthcare setting, were selected from an intervention study sample. They were eligible for this study if they were remitted from their depression and had returned to work for at least 50% of their contract hours at 18 month follow-up. Work functioning was assessed with the Work Limitations Questionnaire (WLQ) and the Need For Recovery scale (NFR). Potential predictors of impaired work functioning were demographic characteristics (assessed at baseline), health characteristics (assessed at baseline, six and twelve month follow-up), and personality- and work characteristics (assessed at 18 month follow-up). After their return to work with MDD in remission, employees were on average still impaired in their work functioning. Personality characteristics were the strongest predictor of this impaired work functioning, followed by health and work characteristics. In the final prediction model, only a passive reaction coping style remained as predictor. We used self-report data with respect to work functioning and work characteristics and not an assessment by a supervisor. Personality trait, coping style, and ability to manage the work environment should be addressed in mental health and return-to-work interventions. Subsequent improved work functioning may be beneficial for mental health and may reduce societal costs. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO{sub 2} overlay coating on TiO{sub 2} nanoparticle working electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xueyang; Fang, Jian [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Gao, Mei [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Wang, Hongxia [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia); Yang, Weidong [CSIRO Materials Science and Engineering, Melbourne, VIC 3169 (Australia); Lin, Tong, E-mail: tong.lin@deakin.edu.au [Institute for Frontier Materials, Deakin University, VIC 3220 (Australia)

    2015-02-01

    Novel TiO{sub 2} single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO{sub 2} nanorods had lower dye loading than TiO{sub 2} nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO{sub 2} nanorods received less resistance than that in TiO{sub 2} nanoparticle aggregation. By just applying a thin layer of TiO{sub 2} nanorods on TiO{sub 2} nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO{sub 2} nanoparticle layer covered with 3 μm thick TiO{sub 2} nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs. - Highlights: • Single crystalline TiO{sub 2} nanorods were prepared for DSSC application. • TiO{sub 2} nanorods show effective light scattering performance. • TiO{sub 2} nanorods have higher electron transfer efficiency than TiO{sub 2} nanoparticles. • TiO{sub 2} nanorods on TiO{sub 2} nanoparticle electrode improve DSSC efficiency.

  11. Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO2 overlay coating on TiO2 nanoparticle working electrode

    International Nuclear Information System (INIS)

    Liu, Xueyang; Fang, Jian; Gao, Mei; Wang, Hongxia; Yang, Weidong; Lin, Tong

    2015-01-01

    Novel TiO 2 single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO 2 nanorods on TiO 2 nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO 2 nanorods had lower dye loading than TiO 2 nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO 2 nanorods received less resistance than that in TiO 2 nanoparticle aggregation. By just applying a thin layer of TiO 2 nanorods on TiO 2 nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO 2 nanoparticle layer covered with 3 μm thick TiO 2 nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs. - Highlights: • Single crystalline TiO 2 nanorods were prepared for DSSC application. • TiO 2 nanorods show effective light scattering performance. • TiO 2 nanorods have higher electron transfer efficiency than TiO 2 nanoparticles. • TiO 2 nanorods on TiO 2 nanoparticle electrode improve DSSC efficiency

  12. Functional capacity and work ability in patients with chronic musculoskeletal pain

    NARCIS (Netherlands)

    van der Meer, Suzan

    2014-01-01

    Patients suffering from chronic low back pain (CLBP) and whiplash associated disorders (WAD) may experience many problems, including in work. Work ability is considered a balance between work demands and personal resources. Functional Capacity Evaluations (FCE) can be used to measure aspects of work

  13. A low-power and miniaturized electrocardiograph data collection system with smart textile electrodes for monitoring of cardiac function.

    Science.gov (United States)

    Dai, Ming; Xiao, Xueliang; Chen, Xin; Lin, Haoming; Wu, Wanqing; Chen, Siping

    2016-12-01

    With the increasing aging population as well as health concerns, chronic heart disease has become the focus of public attention. A comfortable, low-powered, and wearable electrocardiogram (ECG) system for continuously monitoring the elderly's ECG signals over several hours is important for preventing cardiovascular diseases. Traditional ECG monitoring apparatus is often inconvenient to carry, has many electrodes to attach to the chest, and has a high-power consumption. There is also a challenge to design an electrocardiograph that satisfies requirements such as comfort, confinement, and compactness. Based on these considerations, this study presents a biosensor acquisition system for wearable, ubiquitous healthcare applications using three textile electrodes and a recording circuit specialized for ECG monitoring. In addition, several methods were adopted to reduce the power consumption of the device. The proposed system is composed of three parts: (1) an ECG analog front end (AFE), (2) digital signal processing and micro-control circuits, and (3) system software. Digital filter methods were used to eliminate the baseline wander, skin contact noise, and other interfering signals. A comparative study was conducted using this system to observe its performance with two commercial Holter monitors. The experimental results demonstrated that the total power consumption of this proposed system in a full round of ECG acquisition was only 29.74 mW. In addition, this low-power system performed well and stably measured the heart rate with an accuracy of 98.55 %. It can also contain a real-time dynamic display with organic light-emitting diodes (OLED) and wirelessly transmit information via a Bluetooth 4.0 module.

  14. Electrode Processes in Porous Electrodes.

    Science.gov (United States)

    1985-11-26

    F104470 2.0 MASS SPECTROMETRY One part of activity for this year is an investigation of the behavior of silver electrodes through the distribution of...al. (2)). These, in some cases, involve tedious and time comsuming procedures and discrepencies of as much as 15% have been observed in the results. As

  15. The photovoltaic performance of Ag2S quantum dots-sensitized solar cells using plasmonic Au nanoparticles/TiO2 working electrodes

    Science.gov (United States)

    Badawi, Ali; Mostafa, Nasser Y.; Al-Hosiny, Najm M.; Merazga, Amar; Albaradi, Ateyyah M.; Abdel-Wahab, F.; Atta, A. A.

    2018-06-01

    The photovoltaic performance of silver sulfide (Ag2S) quantum dots-sensitized solar cells (QDSSCs) using different concentrations (0, 0.05, 0.1, 0.3 and 0.5 wt.%) of plasmonic Au nanoparticles (NPs)/titania (TiO2) electrodes has been investigated. Ag2S quantum dots (QDs) were adsorbed onto the Au NPs/titania electrodes using the successive ionic layer adsorption and reaction (SILAR) deposition technique. The morphological properties of the Au NPs and the prepared titania electrodes were characterized using transmission electron microscope (TEM) and scanning electron microscope (SEM), respectively. The energy-dispersive X-ray (EDX) spectra of the bare titania and Ag2S QDs-sensitized titania electrodes were recorded. The optical properties of the prepared Ag2S QDs-sensitized titania electrodes were measured using a UV-visible spectrophotometer. The estimated energy band gap of Ag2S QDs-sensitized titania electrodes is 1.96 eV. The photovoltaic performance of the assembled Ag2S QDSSCs was measured under 100 mW/cm2 solar illumination. The optimal photovoltaic parameters were obtained as follows: open circuit voltage Voc = 0.50 V, current density Jsc = 3.18 mA/cm2, fill factor (FF) = 0.35 and energy conversion efficiency η = 0.55% for 0.3 wt.% of Au NPs/titania electrode. These results are attributed to the enhancement in the absorption and decrease in the electron-hole pairs recombination rate. The open circuit voltage decay (OCVD) measurements of the assembled Ag2S QDSSCs were measured. The calculated electron lifetime (τ) in Ag2S QDSSCs with Au NPs/titania electrodes is at least one order of magnitude more than that with bare titania electrode. The cut-on-cut-off cycles of the solar illumination measurements show the rapid sensitivity and good reproducibility of the assembled Ag2S QDSSCs.

  16. Diagnostic Accuracy of the Work Functioning Impairment Scale (WFun): A Method to Detect Workers Who Have Health Problems Affecting their Work and to Evaluate Fitness for Work.

    Science.gov (United States)

    Nagata, Tomohisa; Fujino, Yoshihisa; Saito, Kumi; Uehara, Masamichi; Oyama, Ichiro; Izumi, Hiroyuki; Kubo, Tatsuhiko

    2017-06-01

    This study evaluated the diagnostic accuracy of the Work Functioning Impairment Scale (WFun), a questionnaire to detect workers with health problems which affect their work, using an assessment by an occupational health nurse as objective standard. The WFun was completed by 294 employees. The nurse interviewed to assess 1) health problems; 2) effects of health on their work; necessity for 3) treatment, 4) health care instruction, and 5) consideration of job accommodation. The odds ratio in the high work functioning impairment group compared with the low was highly statistically significant with 9.05, 10.26, 5.77, 9.37, and 14.70, respectively. The WFun demonstrated the high detectability with an area under the receiver operating characteristic of 0.75, 0.81, 0.72, 0.79, and 0.83, respectively. This study suggests that the WFun is useful in detecting those who have health problems affecting their work.

  17. Charge Efficiency: A Functional Tool to Probe the Double-Layer Structure Inside of Porous Electrodes and Application in the Modeling of Capacitive Deionization

    NARCIS (Netherlands)

    Zhao, R.; Biesheuvel, P.M.; Miedema, H.; Bruning, H.; Wal, van der A.

    2010-01-01

    Porous electrodes are important in many physical-chemical processes including capacitive deionization (CDI), a desalination technology where ions are adsorbed from solution into the electrostatic double layers formed at the electrode/solution interface inside of two juxtaposed porous electrodes. A

  18. The reproductive function state of women working at the Smolensk nuclear power plant in shops with hazard working conditions

    International Nuclear Information System (INIS)

    Lyaginskaya, A.M.; Osipov, V.A.; Bugrova, T.I.; Kreusheva, I.F.; Plitkina, V.M.; Karepanova, L.A.; Afanas'eva, R.V.

    2001-01-01

    The reproductive function state of female workers at the Smolensk nuclear power plant in shops with hazardous working conditions is estimated. Female workers occupied in major shops of the Smolensk nuclear power plant are interviewed and subjected to a questionnaire. Individual medical care records of pregnant women and newborns are analyzed. Health statistics data for the town of Desnogorsk are used for comparison. Indicators of the reproductive function among female workers occupied from 1984 up to 1998 at the Smolensk nuclear power plant in workplaces with hazardous working conditions have not been shown to differ from those among the general female population in the town of Desnogorsk: neither these indicators deteriorated during the 14 year period of work as compared with the initial level [ru

  19. Tuning the work function of monolayer graphene on 4H-SiC (0001) with nitric acid

    International Nuclear Information System (INIS)

    Günes, Fethullah; Arezki, Hakim; Alamarguy, David; Alvarez, José; Kleider, Jean-Paul; Boutchich, Mohamed; Pierucci, Debora; Ouerghi, Abdelkarim; Dappe, Yannick J

    2015-01-01

    Chemical doping of graphene is a key process for the modulation of its electronic properties and the design and fabrication of graphene-based nanoelectronic devices. Here, we study the adsorption of diluted concentrations of nitric acid (HNO_3) onto monolayer graphene/4H-SiC (0001) to induce a variation of the graphene work function (WF). Raman spectroscopy indicates an increase in the defect density subsequent to the doping. Moreover, ultraviolet photoemission spectroscopy (UPS) was utilized to quantify the WF shift. UPS data show that the WF of the graphene layer decreased from 4.3 eV (pristine) down to 3.8 eV (30% HNO_3) and then increased to 4.4 eV at 100% HNO_3 concentration. These observations were confirmed using density functional theory (DFT) calculations. This straightforward process allows a large WF modulation, rendering the molecularly modified graphene/4H-SiC(0001) a highly suitable electron or hole injection electrode. (paper)

  20. Does polycystic ovary syndrome affect cognition? : A functional magnetic resonance imaging study exploring working memory

    NARCIS (Netherlands)

    Soleman, Remi S; Kreukels, Baudewijntje P C; Veltman, Dick J; Cohen-Kettenis, Peggy T; Hompes, Peter G A; Drent, Madeleine L; Lambalk, Cornelis B

    OBJECTIVE: To study effects of overexposure to androgens and subsequent antiandrogenic treatment on brain activity during working memory processes in women with polycystic ovary syndrome (PCOS). DESIGN: In this longitudinal study, working memory function was evaluated with the use of functional

  1. Relative work function of clean molybdenum single-crystal planes determined by field emission microscopy

    International Nuclear Information System (INIS)

    Bergeret, G.; Abon, M.; Tardy, B.; Teichner, S.J.

    1974-01-01

    A probe-hole field emission microscope was used to determine the work function of clean molybdenum single crystal planes relative to the average work function of the field emitter, assumed to be 4.20 eV. Results are compared with other available data

  2. Change in the work function of zirconium by oxidation at high temperatures and low oxygen pressures

    International Nuclear Information System (INIS)

    Maeno, Yutaka; Yamamoto, Masahiro; Naito, Shizuo; Mabuchi, Mahito; Hashino, Tomoyasu

    1991-01-01

    Changes in the work function of zirconium on oxidation are measured at oxygen pressures of 3.0 x 10 -6 - 3.0 x 10 -4 Pa and at temperatures in the range 426-775 K. The work function first decreases then increases until a final saturation stage is reached. Use of secondary-ion mass spectroscopy (SIMS) shows that the changes correspond to oxygen adsorption, oxide nucleation and oxide growth, respectively. The initial decrease in work function is interpreted by the incorporation of oxygen adatoms into the subsurface. The oxygen adsorption potential of zirconium is evaluated by an effective medium theory, and the physical origin of the incorporation of oxygen adatoms is discussed. The positive change in the work function caused by oxide formation and the temperature and pressure dependences of the change in the work function by oxidation are explained qualitatively. (author)

  3. Characterisation of nano-interdigitated electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Skjolding, L H D; Ribayrol, A; Montelius, L [Division of Solid State Physics, Lund University, Box 118, SE-221 00 Lund (Sweden); Spegel, C [Department of Analytical Chemistry Lund University, Box 124, SE-221 00 Lund (Sweden); Emneus, J [MIC - Department of Micro and Nanotechnology, DTU - Building 345 East, DK-2800 Kgs. Lyngby (Denmark)], E-mail: lars_henrik.daehli_skjolding@ftf.lth.se

    2008-03-15

    Interdigitated electrodes made up of two individually addressable interdigitated comb-like electrode structures have frequently been suggested as ultra sensitive electrochemical biosensors. Since the signal enhancement effects due to cycling of the reduced and oxidized species are strongly dependent on the inter electrode distances, since the nature of the enhancement is due to overlying diffusion layers, interdigitated electrodes with an electrode separation of less then one micrometer are desired for maximum signal amplification. Fabrication of submicron structures can only be made by advanced lithography techniques. By use of electron beam lithography we have fabricated arrays of interdigitated electrodes with an electrode separation distance of 200 nm and an electrode finger width of likewise 200 nm. The entire electrode structure is 100 micrometre times 100 micrometre, and the active electrode area is dictated by the opening in the passivation layer, that is defined by UV lithography. Here we report measurements of redox cycling of ferrocyanide by coupled cyclic voltammograms, where the potential at one of the working electrodes are varied and either an oxidising or reducing potential is applied to the complimentary interdigitated electrode. The measurements show fast conversion and high collection efficiency round 87% as expected for nano-interdigitated electrodes.

  4. Risk factors for poor work functioning of persons with schizophrenia in rural China.

    Science.gov (United States)

    Ran, Mao-Sheng; Chen, Sheying; Chen, Elaina Y; Ran, Bo-Yu; Tang, Cui-Ping; Lin, Fu-Rong; Li, Li; Li, Si-Gan; Mao, Wen-Jun; Hu, Shi-Hui

    2011-11-01

    The long-term work performance of persons with schizophrenia in the community is unclear. This study examined the status of long-term work functioning and the predictors of poor work status among patients with schizophrenia in a Chinese rural area. A 10-year follow-up investigation (1994-2004) of a cohort (n = 510) of persons with schizophrenia was conducted in Xinjin County, Chengdu, China. Compared with baseline data, work functioning of patients with schizophrenia deteriorated after 10 years. The rates of not working increased significantly from 12.0% in 1994 to 23.0% in 2004. Bivariate analyses showed that the poor work functioning in 2004 was significantly associated with male gender, older age, older age of first onset, higher level of education, longer duration of illness, lower family economic status, lack of caregivers, poor work status in 1994, living in shabby or unstable house, marked symptoms, and higher score on the Social Disability Screening Schedule (SDSS). In multiple logistic regression analyses, higher score of SDSS and poor work status in 1994 were identified as unique predictors of poor work status in 2004. The status of work functioning of persons with schizophrenia decreased over the course of the illness. The risk factors for poor work functioning and specific socio-cultural environment should be considered in planning community mental health services and rehabilitation for these patients.

  5. Work-related measures of physical and behavioral health function: Test-retest reliability.

    Science.gov (United States)

    Marino, Molly Elizabeth; Meterko, Mark; Marfeo, Elizabeth E; McDonough, Christine M; Jette, Alan M; Ni, Pengsheng; Bogusz, Kara; Rasch, Elizabeth K; Brandt, Diane E; Chan, Leighton

    2015-10-01

    The Work Disability Functional Assessment Battery (WD-FAB), developed for potential use by the US Social Security Administration to assess work-related function, currently consists of five multi-item scales assessing physical function and four multi-item scales assessing behavioral health function; the WD-FAB scales are administered as Computerized Adaptive Tests (CATs). The goal of this study was to evaluate the test-retest reliability of the WD-FAB Physical Function and Behavioral Health CATs. We administered the WD-FAB scales twice, 7-10 days apart, to a sample of 376 working age adults and 316 adults with work-disability. Intraclass correlation coefficients were calculated to measure the consistency of the scores between the two administrations. Standard error of measurement (SEM) and minimal detectable change (MDC90) were also calculated to measure the scales precision and sensitivity. For the Physical Function CAT scales, the ICCs ranged from 0.76 to 0.89 in the working age adult sample, and 0.77-0.86 in the sample of adults with work-disability. ICCs for the Behavioral Health CAT scales ranged from 0.66 to 0.70 in the working age adult sample, and 0.77-0.80 in the adults with work-disability. The SEM ranged from 3.25 to 4.55 for the Physical Function scales and 5.27-6.97 for the Behavioral Health function scales. For all scales in both samples, the MDC90 ranged from 7.58 to 16.27. Both the Physical Function and Behavioral Health CATs of the WD-FAB demonstrated good test-retest reliability in adults with work-disability and general adult samples, a critical requirement for assessing work related functioning in disability applicants and in other contexts. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Working Memory Functioning in Children with Learning Disorders and Specific Language Impairment

    Science.gov (United States)

    Schuchardt, Kirsten; Bockmann, Ann-Katrin; Bornemann, Galina; Maehler, Claudia

    2013-01-01

    Purpose: On the basis of Baddeley's working memory model (1986), we examined working memory functioning in children with learning disorders with and without specific language impairment (SLI). We pursued the question whether children with learning disorders exhibit similar working memory deficits as children with additional SLI. Method: In…

  7. Attentional and Executive Function Behaviours in Children with Poor Working Memory

    Science.gov (United States)

    Gathercole, Susan E.; Alloway, Tracy P.; Kirkwood, Hannah J.; Elliott, Julian G.; Holmes, Joni; Hilton, Kerry A.

    2008-01-01

    The purpose of this study was to explore the profiles of classroom behaviour relating to attention and executive functions in children with very poor working memory, and to test the hypothesis that inattentive behaviour and working memory problems co-occur. Teachers rated problem behaviours of 52 children with low working memory scores aged 5/6…

  8. Introducing Thermal Wave Transport Analysis (TWTA): A Thermal Technique for Dopamine Detection by Screen-Printed Electrodes Functionalized with Molecularly Imprinted Polymer (MIP) Particles.

    Science.gov (United States)

    Peeters, Marloes M; van Grinsven, Bart; Foster, Christopher W; Cleij, Thomas J; Banks, Craig E

    2016-04-26

    A novel procedure is developed for producing bulk modified Molecularly Imprinted Polymer (MIP) screen-printed electrodes (SPEs), which involves the direct mixing of the polymer particles within the screen-printed ink. This allowed reduction of the sample preparation time from 45 min to 1 min, and resulted in higher reproducibility of the electrodes. The samples are measured with a novel detection method, namely, thermal wave transport analysis (TWTA), relying on the analysis of thermal waves through a functional interface. As a first proof-of-principle, MIPs for dopamine are developed and successfully incorporated within a bulk modified MIP SPE. The detection limits of dopamine within buffer solutions for the MIP SPEs are determined via three independent techniques. With cyclic voltammetry this was determined to be 4.7 × 10(-6) M, whereas by using the heat-transfer method (HTM) 0.35 × 10(-6) M was obtained, and with the novel TWTA concept 0.26 × 10(-6) M is possible. This TWTA technique is measured simultaneously with HTM and has the benefits of reducing measurement time to less than 5 min and increasing effect size by nearly a factor of two. The two thermal methods are able to enhance dopamine detection by one order of magnitude compared to the electrochemical method. In previous research, it was not possible to measure neurotransmitters in complex samples with HTM, but with the improved signal-to-noise of TWTA for the first time, spiked dopamine concentrations were determined in a relevant food sample. In summary, novel concepts are presented for both the sensor functionalization side by employing screen-printing technology, and on the sensing side, the novel TWTA thermal technique is reported. The developed bio-sensing platform is cost-effective and suitable for mass-production due to the nature of screen-printing technology, which makes it very interesting for neurotransmitter detection in clinical diagnostic applications.

  9. Functional capacity evaluation of work performance among individuals with pelvic injuries following motor vehicle accidents.

    Science.gov (United States)

    Ratzon, Navah Z; Ari Shevil, Eynat Ben; Froom, Paul; Friedman, Sharon; Amit, Yehuda

    2013-01-01

    Pelvic injuries following motor vehicle accidents (MVA) cause disability and affect work capabilities. This study evaluated functional, self-report, and medical-based factors that could predict work capacity as was reflected in a functional capacity evaluation (FCE) among persons who sustained a pelvic injury. It was hypothesized that self-reported functional status and bio-demographic variables would predict work capacity. Sixty-one community-dwelling adults previously hospitalized following a MVA induced pelvic injury. FCE for work performance was conducted using the Physical Work Performance Evaluation (PWPE). Additional data was collected through a demographics questionnaire and the Functional Status Questionnaire. All participants underwent an orthopedic medical examination of the hip and lower extremities. Most participants self-reported that their work capacity post-injury were lower than their job required. PWPE scores indicated below-range functional performance. Regression models predicted 23% to 51% of PWPE subtests. Participants' self-report of functioning (instrumental activities of daily living and work) and bio-demographic variables (gender and age) were better predictors of PWPE scores than factors originating from the medical examination. Results support the inclusion of FCE, in addition to self-report of functioning and medical examination, to evaluate work capacity among individuals' post-pelvic injury and interventions and discharge planning.

  10. Factors predicting work outcome in Japanese patients with schizophrenia: role of multiple functioning levels

    Directory of Open Access Journals (Sweden)

    Chika Sumiyoshi

    2015-09-01

    Full Text Available Functional outcomes in individuals with schizophrenia suggest recovery of cognitive, everyday, and social functioning. Specifically improvement of work status is considered to be most important for their independent living and self-efficacy. The main purposes of the present study were 1 to identify which outcome factors predict occupational functioning, quantified as work hours, and 2 to provide cut-offs on the scales for those factors to attain better work status. Forty-five Japanese patients with schizophrenia and 111 healthy controls entered the study. Cognition, capacity for everyday activities, and social functioning were assessed by the Japanese versions of the MATRICS Cognitive Consensus Battery (MCCB, the UCSD Performance-based Skills Assessment-Brief (UPSA-B, and the Social Functioning Scale Individuals’ version modified for the MATRICS-PASS (Modified SFS for PASS, respectively. Potential factors for work outcome were estimated by multiple linear regression analyses (predicting work hours directly and a multiple logistic regression analyses (predicting dichotomized work status based on work hours. ROC curve analyses were performed to determine cut-off points for differentiating between the better- and poor work status. The results showed that a cognitive component, comprising visual/verbal learning and emotional management, and a social functioning component, comprising independent living and vocational functioning, were potential factors for predicting work hours/status. Cut-off points obtained in ROC analyses indicated that 60–70% achievements on the measures of those factors were expected to maintain the better work status. Our findings suggest that improvement on specific aspects of cognitive and social functioning are important for work outcome in patients with schizophrenia.

  11. Factors predicting work outcome in Japanese patients with schizophrenia: role of multiple functioning levels.

    Science.gov (United States)

    Sumiyoshi, Chika; Harvey, Philip D; Takaki, Manabu; Okahisa, Yuko; Sato, Taku; Sora, Ichiro; Nuechterlein, Keith H; Subotnik, Kenneth L; Sumiyoshi, Tomiki

    2015-09-01

    Functional outcomes in individuals with schizophrenia suggest recovery of cognitive, everyday, and social functioning. Specifically improvement of work status is considered to be most important for their independent living and self-efficacy. The main purposes of the present study were 1) to identify which outcome factors predict occupational functioning, quantified as work hours, and 2) to provide cut-offs on the scales for those factors to attain better work status. Forty-five Japanese patients with schizophrenia and 111 healthy controls entered the study. Cognition, capacity for everyday activities, and social functioning were assessed by the Japanese versions of the MATRICS Cognitive Consensus Battery (MCCB), the UCSD Performance-based Skills Assessment-Brief (UPSA-B), and the Social Functioning Scale Individuals' version modified for the MATRICS-PASS (Modified SFS for PASS), respectively. Potential factors for work outcome were estimated by multiple linear regression analyses (predicting work hours directly) and a multiple logistic regression analyses (predicting dichotomized work status based on work hours). ROC curve analyses were performed to determine cut-off points for differentiating between the better- and poor work status. The results showed that a cognitive component, comprising visual/verbal learning and emotional management, and a social functioning component, comprising independent living and vocational functioning, were potential factors for predicting work hours/status. Cut-off points obtained in ROC analyses indicated that 60-70% achievements on the measures of those factors were expected to maintain the better work status. Our findings suggest that improvement on specific aspects of cognitive and social functioning are important for work outcome in patients with schizophrenia.

  12. Complaint liquid metal electrodes for dielectric elastomer actuators

    Science.gov (United States)

    Finkenauer, Lauren R.; Majidi, Carmel

    2014-03-01

    This work presents a liquid-phase metal electrode to be used with poly(dimethylsiloxane) (PDMS) for a dielectric elastomer actuator (DEA). DEAs are favorable for soft-matter applications where high efficiency and response times are desirable. A consistent challenge faced during the fabrication of these devices is the selection and deposition of electrode material. While numerous designs have been demonstrated with a variety of conductive elastomers and greases, these materials have significant and often intrinsic shortcomings, e.g. low conductivity, hysteresis, incapability of large deformations, and complex fabrication requirements. The liquid metal alloy eutectic Gallium-Indium (EGaIn) is a promising alternative to existing compliant electrodes, having both high conductivity and complete soft-matter functionality. The liquid electrode shares almost the same electrical conductivity as conventional metal wiring and provides no mechanical resistance to bending or stretching of the DEA. This research establishes a straightforward and effective method for quickly depositing EGaIn electrodes, which can be adapted for batch fabrication, and demonstrates the successful actuation of sample curved cantilever elastomer actuators using these electrodes. As with the vast majority of electrostatically actuated elastomer devices, the voltage requirements for these curved DEAs are still quite significant, though modifications to the fabrication process show some improved electrical properties. The ease and speed with which this method can be implemented suggests that the development of a more electronically efficient device is realistic and worthwhile.

  13. A Conceptual Foundation for Measures of Physical Function and Behavioral Health Function for Social Security Work Disability Evaluation

    Science.gov (United States)

    Marfeo, Elizabeth E.; Haley, Stephen M.; Jette, Alan M.; Eisen, Susan V.; Ni, Pengsheng; Bogusz, Kara; Meterko, Mark; McDonough, Christine M.; Chan, Leighton; Brandt, Diane E.; Rasch, Elizabeth K.

    2014-01-01

    Physical and mental impairments represent the two largest health condition categories for which workers receive Social Security disability benefits. Comprehensive assessment of physical and mental impairments should include aspects beyond medical conditions such as a person’s underlying capabilities as well as activity demands relevant to the context of work. The objective of this paper is to describe the initial conceptual stages of developing new measurement instruments of behavioral health and physical functioning relevant for Social Security work disability evaluation purposes. To outline a clear conceptualization of the constructs to be measured, two content models were developed using structured and informal qualitative approaches. We performed a structured literature review focusing on work disability and incorporating aspects of the International Classification of Functioning, Disability, and Health (ICF) as a unifying taxonomy for framework development. Expert interviews provided advice and consultation to enhance face validity of the resulting content models. The content model for work-related behavioral health function identifies five major domains (1) Behavior Control, (2) Basic Interactions, (3) Temperament and Personality, (4) Adaptability, and (5) Workplace Behaviors. The content model describing physical functioning includes three domains (1) Changing and Maintaining Body Position, (2) Whole Body Mobility, and (3) Carrying, Moving and Handling Objects. These content models informed subsequent measurement properties including item development, measurement scale construction, and provided conceptual coherence guiding future empirical inquiry. The proposed measurement approaches show promise to comprehensively and systematically assess physical and behavioral health functioning relevant to work. PMID:23548543

  14. Subjective cognitive complaints, psychosocial factors and nursing work function in nurses providing direct patient care.

    Science.gov (United States)

    Barbe, Tammy; Kimble, Laura P; Rubenstein, Cynthia

    2018-04-01

    The aim of this study was to examine relationships among subjective cognitive complaints, psychosocial factors and nursing work function in nurses providing direct patient care. Cognitive functioning is a critical component for nurses in the assurance of error prevention, identification and correction when caring for patients. Negative changes in nurses' cognitive and psychosocial functioning can adversely affect nursing care and patient outcomes. A descriptive correlational design with stratified random sampling. The sample included 96 nurses from the major geographic regions of the United States. Over 9 months in 2016-2017, data were collected using a web-based survey. Stepwise multiple linear regression analyses were used to examine relationships among subjective cognitive complaints, psychosocial factors and nursing work function. Overall, participants reported minimal work function impairment and low levels of subjective cognitive complaints, depression and stress. In multivariate analyses, depression was not associated with nurses' work function. However, perceived stress and subjective concerns about cognitive function were associated with greater impairment of work function. Nurses experiencing subjective cognitive complaints should be encouraged to address personal and environmental factors that are associated with their cognitive status. Additionally, stress reduction in nurses should be a high priority as a potential intervention to promote optimal functioning of nurses providing direct patient care. Healthcare institutions should integrate individual and institutional strategies to reduce factors contributing to workplace stress. © 2017 John Wiley & Sons Ltd.

  15. Development of the work function monitoring method for a converter of a negative ion source

    International Nuclear Information System (INIS)

    Yamaoka, Hitoshi; Sasao, Mamiko; Wada, Motoi; Ramos, H.J.

    1988-07-01

    A method to monitor the change in the work function of the converter surface in a self-extraction negative ion source is developed. The photoelectron emission from the Cs-Mo surface in a plasma is detected by irradiating surface with laser lights. Negative ions produced at the surface shows a strong correlation with the photoelectron current from the surface in hydrogen and helium discharges. The photoelectron current induced by the Ar + laser is used to detect the change in the cesium coverage, or the work function, while that by the dye laser is found to be suitable to confirm the region of the work function minimum. (author)

  16. Influence of uranium dioxide nonstoichiometric oxygen on the work function of Mo(110) single crystal

    International Nuclear Information System (INIS)

    Bekmukhabetov, E.S.; Dzhajmurzin, A.A.; Imanbekov, Zh.Zh.

    1985-01-01

    The influence of the uranium dioxide nonstoichiometric oxygen on the work function of a Mo(110) single crystal has been studied. When the surface diffusion of oxygen on the tested surface takes place, the work function is shown to decrease and, subsequently, to increase until it becomes stable. The dependence of the work function on the temperature of the specimen in the range of 1600-1900 K with a minimum at 1730 K has been found. The minimum is attributed to the dipole layer formation

  17. Control of indium tin oxide anode work function modified using Langmuir-Blodgett monolayer for high-efficiency organic photovoltaics

    Directory of Open Access Journals (Sweden)

    Yuya Yokokura

    2017-08-01

    Full Text Available The use of Langmuir-Blodgett (LB monolayers to modify the indium tin oxide (ITO work function and thus improve the performance of zinc phthalocyanine (ZnPc/fullerene (C60-based and boron subphthalocyanine chloride (SubPc/C60-based small molecule organic photovoltaic devices (OPVs was examined. In general, LB precursor compounds contain one or more long alkyl chain substituents that can act as spacers to prevent electrical contact with adjoining electrode surfaces. As one example of such a compound, arachidic acid (CH3(CH218COOH was inserted in the forms of one-layer, three-layer or five-layer LB films between the anode ITO layer and the p-type layer in ZnPc-C60-based OPVs to investigate the effects of the long alkyl chain group when it acts as an electrically insulating spacer. The short-circuit current density (Jsc values of the OPVs with the three- and five-layer inserts (1.78 mA·cm−2 and 0.61 mA·cm−2, respectively were reduced dramatically, whereas the Jsc value for the OPV with the single-layer insertion (2.88 mA·cm−2 was comparable to that of the OPV without any insert (3.14 mA·cm-2. The ITO work function was shifted positively by LB deposition of a surfactant compound, C9F19C2H4-O-C2H4-COOH (PFECA, which contained a fluorinated head group. This positive effect was maintained even after formation of an upper p-type organic layer. The Jsc and open-circuit voltage (Voc of the SubPc-C60-based OPV with the LB-modified ITO layers were effectively enhanced. As a result, a 42% increase in device efficiency was achieved.

  18. Schiff Base modified on CPE electrode and PCB gold electrode for selective determination of silver ion

    Science.gov (United States)

    Leepheng, Piyawan; Suramitr, Songwut; Phromyothin, Darinee

    2017-09-01

    The schiff base was synthesized by 2,5-thiophenedicarboxaldehyde and 1,2,4-thiadiazole-3,5-diamine with condensation method. There was modified on carbon paste electrode (CPE) and Printed circuit board (PCB) gold electrode for determination silver ion. The schiff base modified electrodes was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The electrochemical study was reported by cyclic voltammetry method and impedance spectroscopy using modified electrode as working electrode, platinum wire and Ag/AgCl as counter electrode and reference electrode, respectively. The modified electrodes have suitable detection for Ag+. The determination of silver ions using the modified electrodes depended linearly on Ag+ concentration in the range 1×10-10 M to 1×10-7 M, with cyclic voltammetry sensitivity were 2.51×108 μAM-1 and 1.88×108 μAM-1 for PCB gold electrode and CPE electrode, respectively, limits of detection were 5.33×10-9 M and 1.99×10-8 M for PCB gold electrode and CPE electrode, respectively. The modified electrodes have high accuracy, inexpensive and can applied to detection Ag+ in real samples.

  19. Luigi Gatteschi's work on asymptotics of special functions and their zeros

    Science.gov (United States)

    Gautschi, Walter; Giordano, Carla

    2008-12-01

    A good portion of Gatteschi's research publications-about 65%-is devoted to asymptotics of special functions and their zeros. Most prominently among the special functions studied figure classical orthogonal polynomials, notably Jacobi polynomials and their special cases, Laguerre polynomials, and Hermite polynomials by implication. Other important classes of special functions dealt with are Bessel functions of the first and second kind, Airy functions, and confluent hypergeometric functions, both in Tricomi's and Whittaker's form. This work is reviewed here, and organized along methodological lines.

  20. A preparation of homogeneous distribution of palladium nanoparticle on poly (acrylic acid)-functionalized graphene oxide modified electrode for formalin oxidation

    International Nuclear Information System (INIS)

    Kongkaew, Supatinee; Kanatharana, Proespichaya; Thavarungkul, Panote; Limbut, Warakorn

    2017-01-01

    An excellent electrocatalytic activity, repeatability and stability of electrochemical sensor for formalin detection was fabricated based on a homogeneous distribution of ellipsoidal palladium nanoparticle (PdNPs) on poly (acrylic acid)-functionalized graphene oxide (PAA-GO) modified on a glassy carbon electrode (GCE) (PdNPs-PAA-GO/GCE) with incorporated flow injection amperometry (FI-Amp). Homogeneous distribution of ellipsoidal palladium nanoparticles (PdNPs) were dispersed on PAA-GO via an electroless deposition method. The surface morphology and electrochemical behavior of the PdNPs-PAA-GO/GCE were characterized by transmission electron microscopy, fourier transform infrared spectroscopy, cyclic voltammetry and amperometry. The PdNPs-PAA-GO/GCE exhibited excellent electrocatalytic activity toward formalin oxidation. Then this modified electrode was incorporated with FI-Amp for formalin sensor development. In order to obtain good analytical performances, many parameters such as the amount of PdNPs-PAA-GO, applied potential, flow rate and sample volume were optimized. Under optimal conditions, this sensor provided a wide linear range, 50-50,000 μmol L −1 , with high sensitivity (320 μA mmol L −1 cm −2 ). The limit of detection and limit of quantitation were 16 μmol L −1 and 53 μmol L −1 , respectively. This proposed sensor exhibited good repeatability (RSD < 3.5%), excellence stability (RSD = 1.5%, n = 500) and high sample throughput (60 samples h −1 ). This method was applied to the determination of formalin in soaked fresh food samples with satisfactory recovery.

  1. Functionalized Graphene–Polyoxometalate Nanodots Assembly as “Organic–Inorganic” Hybrid Supercapacitors and Insights into Electrode/Electrolyte Interfacial Processes

    Directory of Open Access Journals (Sweden)

    Sanju Gupta

    2017-07-01

    Full Text Available The stable high-performance electrochemical electrodes consisting of supercapacitive reduced graphene oxide (rGO nanosheets decorated with pseudocapacitive polyoxometalates (phosphomolybdate acid-H3PMo12O40 (POM and phosphotungstic acid-H3PW12O40 (POW nanodots/nanoclusters are hydrothermally synthesized. The interactions between rGO and POM (and POW components create emergent “organic–inorganic” hybrids with desirable physicochemical properties (specific surface area, mechanical strength, diffusion, facile electron and ion transport enabled by molecularly bridged (covalently and electrostatically tailored interfaces for electrical energy storage. The synergistic hybridization between two electrochemical energy storage mechanisms, electrochemical double-layer from rGO and redox activity (faradaic of nanoscale POM (and POW nanodots, and the superior operating voltage due to high overpotential yielded converge yielding a significantly improved electrochemical performance. They include increase in specific capacitance from 70 F·g−1 for rGO to 350 F·g−1 for hybrid material with aqueous electrolyte (0.4 M sodium sulfate, higher current carrying capacity (>10 A·g−1 and excellent retention (94% resulting higher specific energy and specific power density. We performed scanning electrochemical microscopy to gain insights into physicochemical processes and quantitatively determine associated parameters (diffusion coefficient (D and heterogeneous electron transfer rate (kET at electrode/electrolyte interface besides mapping electrochemical (reactivity and electro-active site distribution. The experimental findings are attributed to: (1 mesoporous network and topologically multiplexed conductive pathways; (2 higher density of graphene edge plane sites; and (3 localized pockets of re-hybridized orbital engineered modulated band structure provided by polyoxometalates anchored chemically on functionalized graphene nanosheets, contribute toward

  2. Changes in working conditions and physical health functioning among midlife and ageing employees.

    Science.gov (United States)

    Mänty, Minna; Kouvonen, Anne; Lallukka, Tea; Lahti, Jouni; Lahelma, Eero; Rahkonen, Ossi

    2015-11-01

    The aim this study was to examine the effect of changes in physical and psychosocial working conditions on physical health functioning among ageing municipal employees. Follow-up survey data were collected from midlife employees of the City of Helsinki, Finland, at three time points: wave 1 (2000-2002), wave 2 (2007), and wave 3 (2012). Changes in physical and psychosocial working conditions were assessed between waves 1 and 2. Physical health functioning was measured by the physical component summary (PCS) of the Short-Form 36 questionnaire at each of the three waves. In total, 2784 respondents (83% women) who remained employed over the follow-up were available for the analyses. Linear mixed-effect models were used to assess the associations and adjust for key covariates (age, gender, obesity, chronic diseases, and health behaviors). Repeated and increased exposure to adverse physical working conditions was associated with greater decline in physical health functioning over time. In contrast, decrease in exposures reduced the decline. Of the psychosocial working conditions, changes in job demands had no effects on physical health functioning. However, decreased job control was associated with greater decline and repeated high or increased job control reduced the decline in physical health functioning over time. Adverse changes in physical working conditions and job control were associated with greater decline in physical health functioning over time, whereas favorable changes in these exposures reduced the decline. Preventing deterioration and promoting improvement of working conditions are likely to help maintain better physical health functioning among ageing employees.

  3. Cognitive functioning, aging, and work: A review and recommendations for research and practice.

    Science.gov (United States)

    Fisher, Gwenith G; Chaffee, Dorey S; Tetrick, Lois E; Davalos, Deana B; Potter, Guy G

    2017-07-01

    There is a larger proportion and number of older adults in the labor force than ever before. Furthermore, older adults in the workforce are working until later ages. Although a great deal of research has examined physical health and well-being of working older adults, less research has focused on cognitive functioning. The purpose of this article is to provide a broad contemporary and multidisciplinary review of the intersection between cognitive functioning, aging, and work as a follow-up to a paper previously written by Fisher et al. (2014). We begin by providing definitions and background about cognitive functioning and how it changes over the life span. Next we discuss theories relevant to the intersection of cognitive functioning and work, including the use-it-or-lose-it hypothesis, the cognitive reserve hypothesis, hypotheses regarding environmental influences on intellectual functioning, and the job-demands-resources model. Then we summarize recent research about the effects of work on cognitive functioning, as well as ways that cognitive functioning may influence work motivation, learning, development, training, and safety. We conclude by emphasizing the importance of person-environment fit, suggesting avenues for future research, and discussing practical implications for the field of occupational health psychology. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  4. Improved functional capacity evaluation performance predicts successful return to work one year after completing a functional restoration rehabilitation program.

    Science.gov (United States)

    Fore, Lisa; Perez, Yoheli; Neblett, Randy; Asih, Sali; Mayer, Tom G; Gatchel, Robert J

    2015-04-01

    To evaluate whether functional capacity evaluation (FCE) scores are responsive to functional restoration treatment, and to assess the ability of FCEs at program discharge to predict work outcomes. An interdisciplinary cohort study of prospectively collected data. A functional restoration center. A consecutive sample of 354 patients with chronic disabling occupational musculoskeletal disorders (CDOMDs) completed a functional restoration program consisting of quantitatively directed exercise progression and multi-modal disability management with interdisciplinary medical supervision. Each patient participated in an FCE at admission and discharge from treatment. The results of each FCE yielded the physical demand level (PDL) at which patients were functioning. Patients were initially divided into 5 PDL groups, based on job-of-injury lifting, carrying, and pushing/pulling requirements, for the pre- to posttreatment responsiveness analyses. Patients were subsequently divided into 5 PDL groups, based on their performance on the FCE upon program completion. Outcome measures included admission-to-discharge changes in PDLs and 2 specific FCE lifting tasks: isokinetic lifting; and the Progressive Isoinertial Lifting Evaluation (PILE). Socioeconomic outcomes were also evaluated, including post-discharge work return and work retention 1-year after treatment completion. Overall, 96% of the patients demonstrated improvement in their PDLs from admission to discharge. A majority of patients (56%) were able to achieve a discharge PDL that was comparable to their estimated job-of-injury lifting requirement or higher (P work return (P work retention (P work return after treatment completion and work retention 1 year later. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  5. A functional magnetic resonance imaging study of working memory in youth after sports-related concussion: is it still working?

    Science.gov (United States)

    Keightley, Michelle L; Saluja, Rajeet Singh; Chen, Jen-Kai; Gagnon, Isabelle; Leonard, Gabriel; Petrides, Michael; Ptito, Alain

    2014-03-01

    Abstract In children, the importance of detecting deficits after mild traumatic brain injury (mTBI) or concussion has grown with the increasing popularity of leisure physical activities and contact sports. Whereas most postconcussive symptoms (PCS) are similar for children and adults, the breadth of consequences to children remains largely unknown. To investigate the effect of mTBI on brain function, we compared working memory performance and related brain activity using blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in 15 concussed youths and 15 healthy age-matched control subjects. Neuropsychological tests, self-perceived PCS, and levels of anxiety and depression were also assessed. Our results showed that, behaviorally, concussed youths had significantly worse performances on the working memory tasks, as well as on the Rey figure delayed recall and verbal fluency. fMRI results revealed that, compared to healthy children, concussed youths had significantly reduced task-related activity in bilateral dorsolateral prefrontal cortex, left premotor cortex, supplementary motor area, and left superior parietal lobule during performance of verbal and nonverbal working memory tasks. Additionally, concussed youths also showed less activation than healthy controls in the dorsal anterior cingulate cortex, left thalamus, and left caudate nucleus during the nonverbal task. Regression analysis indicated that BOLD signal changes in bilateral dorsolateral prefrontal cortex were significantly correlated with performance such that greater activities in these regions, relative to the control condition, were associated with greater accuracy. Our findings confirmed functional alterations in brain activity after concussion in youths, a result similar to that observed in adults. However, significant differences were noted. In particular, the observation of reduced working memory accuracy suggests that youths may be unable to engage compensatory

  6. Control of work function of graphene by plasma assisted nitrogen doping

    International Nuclear Information System (INIS)

    Akada, Keishi; Terasawa, Tomo-o; Imamura, Gaku; Obata, Seiji; Saiki, Koichiro

    2014-01-01

    Nitrogen doping is expected to provide several intriguing properties to graphene. Nitrogen plasma treatment to defect-free and defective highly oriented pyrolytic graphite (HOPG) samples causes doping of nitrogen atom into the graphene layer. Nitrogen atoms are initially doped at a graphitic site (inside the graphene) for the defect-free HOPG, while doping to a pyridinic or a pyrrolic site (edge of the graphene) is dominant for the defective HOPG. The work function of graphene correlates strongly with the site and amount of doped nitrogen. Nitrogen atoms doped at a graphitic site lower the work function, while nitrogen atoms at a pyridinic or a pyrrolic site increase the work function. Control of plasma treatment time and the amount of initial defect could change the work function of graphite from 4.3 eV to 5.4 eV, which would open a way to tailor the nature of graphene for various industrial applications

  7. The function of specialized organization in work safety engineering for nuclear installations

    International Nuclear Information System (INIS)

    Salvatore, J.E.L.

    1989-01-01

    The attributions of Brazilian CNEN in the licensing procedures of any nuclear installation are discussed. It is shown that the work safety engineering and industrial safety constitute important functions for nuclear safety. (M.C.K.) [pt

  8. The effect of work function changes on secondary ion energy spectra

    International Nuclear Information System (INIS)

    Wittmaack, K.

    1983-01-01

    The effect of work function changes on experimental secondary ion energy spectra is discussed. In agreement with theory the measured ion intensities frequently exhibit an exponential work function dependence. However, the predicted velocity dependence is only observed at fairly high secondary ion energies. In the absence of a velocity dependence of the degree of ionization measured shifts of energy spectra reflect work function changes directly. Various instrumental problems are shown to aggravate a detailed comparison between experiment and theory. Significant artefacts must be expected if the extraction field is of the order of or less than the lateral field induced by a work function difference between the bombarded spot and the surrounding sample surface. (Auth.)

  9. Measuring dynamic process of working memory training with functional brain networks

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2015-12-01

    Full Text Available In this paper, we proposed the functional brain networks and graphic theory method to measure the effect of working memory training on the neural activities. 12 subjects were recruited in this study, and they did the same working memory task before they had been trained and after training. We architected functional brain networks based on EEG coherence and calculated properties of brain networks to measure the neural co-activities and the working memory level of subjects. As the result, the internal connections in frontal region decreased after working memory training, but the connection between frontal region and top region increased. And the more small-world feature was observed after training. The features observed above were in alpha (8-13 Hz and beta (13-30 Hz bands. The functional brain networks based on EEG coherence proposed in this paper can be used as the indicator of working memory level.

  10. Improving arm function in chronic stroke: a pilot study of sensory amplitude electrical stimulation via glove electrode during task-specific training.

    Science.gov (United States)

    Sullivan, Jane; Girardi, Madeline; Hensley, Melissa; Rohaus, Jordan; Schewe, Clay; Whittey, Colby; Hansen, Piper; Muir, Kimberly

    2015-06-01

    To investigate the effects of sensory amplitude electrical stimulation (SES) delivered by glove electrode during task-specific exercise on arm movement, function, and sensation in chronic stroke. The design was an intervention pilot study, pre-test, post-test, follow-up design. The settings used were a university research laboratory and home-based intervention. Participants comprised of 11 individuals with chronic stroke (7.2 ± 4.1 years post onset) and moderate arm paresis, 10.82/20 ± 2.27 on the Stroke Rehabilitation Assessment of Movement (STREAM) - Arm Subscale. Participants were seven males and four females (mean age: 59 years). Participants were recruited from university-based database. Intervention- Participants engaged in task-specific training at home for 30 min, twice daily, for 5 weeks, while receiving SES via glove electrode. Participants received supervised task practice at least twice during intervention period for 1 hour. Main outcome measures- Jebsen-Taylor Hand Function Test (JTHFT), STREAM - Arm Subscale, Motor Activity Log-14 (MAL-14) - Amount and Quality Subscales, and Nottingham Stereognosis Assessment (NSA). Significant changes were found in group mean pre- and post-test comparisons on the NSA (P = 0.042), MAL amount subscale (P = 0.047), and JTHFT (with writing item 29 excluded) (P = 0.003) and in pre-test to follow-up comparisons on NSA (P = 0.027) and JTHFT (writing item excluded) (P = 0.009). There was no significant change on the STREAM (P = 1.0). Individuals with a greater baseline motor capacity determined by STREAM scores (P = 0.048) and more recent stroke (P = 0.014) had significantly greater improvements. Combining task-specific training with glove-based SES in chronic stroke resulted in changes in arm sensation and function that were maintained at 3-month follow-up.

  11. METHODS FOR LOCAL CHANGES IN THE PLASTIC DEFORMATION DIAGNOSTICS ON THE WORK FUNCTION

    Directory of Open Access Journals (Sweden)

    K. V. Panteleyev

    2015-01-01

    Full Text Available The paper describes the electronic work function measurements by the contact potential difference technique, and experimental demonstration of the possibility of these methods application for the stress-strain state of the surface layer of the metals and alloys. The techniques end examples of their application of localization of plastic deformation studies using the Kelvin probe are developed and present. The study topology of work function the deformed surface possible to determine the type of deformation and dynamics of

  12. Correlation of H- production and the work function of a surface in a hydrogen plasma

    International Nuclear Information System (INIS)

    Wada, M.

    1983-03-01

    Surface-plasma negative hydrogen ion sources are being developed as possible parts for future neutral beam systems. In these ion sources, negative hydrogen ions (H - ) are produced at low work function metal surfaces immersed in hydrogen plasmas. To investigate the correlation between the work function and the H - production at the surface with a condition similar to the one in the actual plasma ion source, these two parameters were simultaneously measured in the hydrogen plasma environment

  13. Storage and Processing Working Memory Functions in Alzheimer-Type Dementia

    OpenAIRE

    Vecchi, T.; Saveriano, V.; Paciaroni, L.

    1999-01-01

    A selective deterioration of working memory functions has been suggested as an explanation of the cognitive decay occurring in normal ageing as well as in Alzheimer-type dementia. Recent studies have highlighted that elderly people’s limitations in working memory functions may be better interpreted when analysing the specific characteristics of the cognitive process (i.e., passive storage or active manipulation of information). In the present study, we have adapted a procedure used to investi...

  14. Background reduction of the KATRIN spectrometers. Transmission function of the pre-spectrometer and systematic tests of the main-spectrometer wire electrode

    Energy Technology Data Exchange (ETDEWEB)

    Prall, Matthias

    2011-07-04

    precision). These measurements, together with the results of various quality assurance tests are stored in a database allowing to reconstruct the properties and history of each single electrode module. The UHV-compatible, fail-save, non-magnetic high voltage distribution, routing 46 voltages to the electrode modules inside the MS, was designed, tested systematically and its installation was started. The pre-spectrometer (PS), which has the same working principle as the MS is placed in front of it in the KATRIN experiment. It is foreseen to operate the MS at a potential of about 18.57 keV and the PS at about 18.3 keV reducing the rate of {beta}-decay electrons entering the MS to about 10{sup 3} s{sup -1}. This measure reduces the electron scattering probability in the MS and thus the background rate. Like this, however, electrons are confined longitudinally between the spectrometer potentials and radially by the strong magnetic field of a solenoid, placed between them. The electrons trapped in this Penning trap can also produce background. This work investigates the possibility to diminish this background source by reducing the PS potential by several keV worsening the trapping conditions. In this configuration, however, the PS transmission probability could be reduced as an adiabaticity requirement guaranteeing that electrons follow the magnetic field lines through the PS and are transmitted, is potentially violated. This phenomenon would introduce an additional systematic uncertainty for KATRIN. Therefore, the pre-spectrometer transmission at several magnetic fields settings. These investigations show that there are no non-adiabatic transmission losses for magnetic fields larger, or equal to 2.25 T (50% KATRIN design value).

  15. Theoretical studies of the work functions of Pd-based bimetallic surfaces

    International Nuclear Information System (INIS)

    Ding, Zhao-Bin; Wu, Feng; Wang, Yue-Chao; Jiang, Hong

    2015-01-01

    Work functions of Pd-based bimetallic surfaces, including mainly M/Pd(111), Pd/M, and Pd/M/Pd(111) (M = 4d transition metals, Cu, Au, and Pt), are studied using density functional theory. We find that the work function of these bimetallic surfaces is significantly different from that of parent metals. Careful analysis based on Bader charges and electron density difference indicates that the variation of the work function in bimetallic surfaces can be mainly attributed to two factors: (1) charge transfer between the two different metals as a result of their different intrinsic electronegativity, and (2) the charge redistribution induced by chemical bonding between the top two layers. The first factor can be related to the contact potential, i.e., the work function difference between two metals in direct contact, and the second factor can be well characterized by the change in the charge spilling out into vacuum. We also find that the variation in the work functions of Pd/M/Pd(111) surfaces correlates very well with the variation of the d-band center of the surface Pd atom. The findings in this work can be used to provide general guidelines to design new bimetallic surfaces with desired electronic properties

  16. Variations in erosive wear of metallic materials with temperature via the electron work function

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaochen; Yu, Bin [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Yan, X.G. [School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China); Li, D.Y., E-mail: dongyang.li@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China)

    2016-04-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  17. Effects of Marital Status and Shift Work on Family Function among Registered Nurses

    Science.gov (United States)

    TAI, Shu-Yu; LIN, Pei-Chen; CHEN, Yao-Mei; HUNG, Hsin-Chia; PAN, Chih-Hong; PAN, Shung-Mei; LEE, Chung-Yin; HUANG, Chia-Tsuan; WU, Ming-Tsang

    2014-01-01

    This study aims to assess the interactive effect of marital status and shift work on family function. A population-based sample of 1,438 nurses between the ages of 20–45 yr was recruited from Taiwan during the period from July 2005 to April 2006 using a mailed questionnaire. The self-administered questionnaire contained information about demographic data, work status, shift work schedule, and the Family APGAR (Adaptation, Partnership, Growth, Affection, and Resolve) Scale, to evaluate family function. Compared to day shift nurses, non-night and rotation shift nurses had 1.53- and 1.38-fold (95% CI=1.09–2.14 and 1.01–1.88) risk to have poor family function after adjusting for other covariates. Married nurses, by contrast, had a 0.44-fold (95% CI=0.29–0.66) risk to have poor family function compared to single nurses. In addition, married nurses who worked non-night or rotation shifts had a significantly higher percent of poor family function than those married nurses working day shifts; however, similar results were not replicated in single nurses. We concluded that shift work and marital status could influence family function. PMID:24909112

  18. Work function mediated by deposition of ultrathin polar FeO on Pt(111)

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shuangzan; Qin, Zhihui; Guo, Qinmin; Cao, Gengyu, E-mail: gycao@wipm.ac.cn

    2017-01-15

    Highlights: • Growth of FeO layers on Pt(111) is found to consecutively reduce the work function of the system. • The electrostatic compression effect and the structural relaxation make major contributions to the reductions. • Significant rectifying effect observed in the FeO layer is induced by band alignment shift as work function changing. - Abstract: Significant work function changes from bare Pt(111) surface to 1 monolayer and 2 monolayers of ultrathin iron oxide (FeO) films on it are investigated by means of scanning tunneling microscopy/spectroscopy (STM/STS). With FeO layer-by-layer growth, a continuous reduction of the work function along with the surface vacuum level (VL) shifting is observed. We found that the compression of the electron spill-out at the metal-oxide interface and the substantial reconstruction of 2 ML FeO film, respectively, make major contributions to the first and the second reductions of the work function. The rectifying effect in FeO films is also observed, which is attributed to the downward shift of band alignment imposed by the total change in surface dipole. Our work shows that the polar oxide films play an important role to adjust surface electronic structures for enhancing device functionality.

  19. Effects of marital status and shift work on family function among registered nurses.

    Science.gov (United States)

    Tai, Shu-Yu; Lin, Pei-Chen; Chen, Yao-Mei; Hung, Hsin-Chia; Pan, Chih-Hong; Pan, Shung-Mei; Lee, Chung-Yin; Huang, Chia-Tsuan; Wu, Ming-Tsang

    2014-01-01

    This study aims to assess the interactive effect of marital status and shift work on family function. A population-based sample of 1,438 nurses between the ages of 20-45 yr was recruited from Taiwan during the period from July 2005 to April 2006 using a mailed questionnaire. The self-administered questionnaire contained information about demographic data, work status, shift work schedule, and the Family APGAR (Adaptation, Partnership, Growth, Affection, and Resolve) Scale, to evaluate family function. Compared to day shift nurses, non-night and rotation shift nurses had 1.53- and 1.38-fold (95% CI=1.09-2.14 and 1.01-1.88) risk to have poor family function after adjusting for other covariates. Married nurses, by contrast, had a 0.44-fold (95% CI=0.29-0.66) risk to have poor family function compared to single nurses. In addition, married nurses who worked non-night or rotation shifts had a significantly higher percent of poor family function than those married nurses working day shifts; however, similar results were not replicated in single nurses. We concluded that shift work and marital status could influence family function.

  20. Work function mediated by deposition of ultrathin polar FeO on Pt(111)

    International Nuclear Information System (INIS)

    Lu, Shuangzan; Qin, Zhihui; Guo, Qinmin; Cao, Gengyu

    2017-01-01

    Highlights: • Growth of FeO layers on Pt(111) is found to consecutively reduce the work function of the system. • The electrostatic compression effect and the structural relaxation make major contributions to the reductions. • Significant rectifying effect observed in the FeO layer is induced by band alignment shift as work function changing. - Abstract: Significant work function changes from bare Pt(111) surface to 1 monolayer and 2 monolayers of ultrathin iron oxide (FeO) films on it are investigated by means of scanning tunneling microscopy/spectroscopy (STM/STS). With FeO layer-by-layer growth, a continuous reduction of the work function along with the surface vacuum level (VL) shifting is observed. We found that the compression of the electron spill-out at the metal-oxide interface and the substantial reconstruction of 2 ML FeO film, respectively, make major contributions to the first and the second reductions of the work function. The rectifying effect in FeO films is also observed, which is attributed to the downward shift of band alignment imposed by the total change in surface dipole. Our work shows that the polar oxide films play an important role to adjust surface electronic structures for enhancing device functionality.

  1. Performances of carbon-based screen-printed electrodes modified by diazonium salts with various carboxylic functions for trace metal sensors

    International Nuclear Information System (INIS)

    Bouden, Sarra; Bellakhal, Nizar; Chausse, Annie; Vautrin-Ul, Christine

    2014-01-01

    The electrochemically induced functionalization of carbon-based screen-printed-electrodes (SPEs) by phenyl groups, having one or two carboxylic functions, was achieved by reduction of in situ generated diazonium salts in aqueous media. The corresponding diazonium cations of 4-aminobenzoic acid, 4-aminophthalic acid, 3-(4-aminophenyl) propionic acid, 3-(4-aminophenyl)-2-propenoic acid and 5-aminoisophthalic acid were generated in situ with sodium nitrite in aqueous H_2SO_4. The electrochemical detection of Pb(II) with the grafted SPEs was investigated using Pb(II) 5 * 10"-"8 M solutions. The performances of the grafted SPEs were found to be dependent on the number of carboxylic groups, on their position on the phenyl ring, on the olefinic or the aliphatic character of the chain bearing the carboxylic group. The performances of mono-4-carboxyphenyl and 3,5-dicarboxyphenyl grafted SPEs for Cd(II) and Cu(II) trace detection were tested and compared. (authors)

  2. Vladimir I Arnold - Collected Works Representations of Functions, Celestial Mechanics, and KAM Theory 1957-1965

    CERN Document Server

    Arnold, Vladimir I; Khesin, Boris

    2010-01-01

    Vladimir Arnold is one of the great mathematical scientists of our time. He is famous for both the breadth and the depth of his work. At the same time he is one of the most prolific and outstanding mathematical authors. This first volume of his Collected Works focuses on representations of functions, celestial mechanics, and KAM theory.

  3. Test-retest reliability of the isernhagen work systems functional capacity evaluation in healthy adults

    NARCIS (Netherlands)

    Reneman, MF; Brouwer, S; Meinema, A; Dijkstra, PU; Geertzen, JHB; Groothoff, JW

    2004-01-01

    Aim of this study was to investigate test-retest reliability of the Isernhagen Work System Functional Capacity Evaluation (IWS FCE) in healthy subjects. The IWS FCE consists of 28 tests that reflect work-related activities such as lifting, carrying, bending, etc. A convenience sample of 26 healthy

  4. CRITIQUE OF FUNCTIONALISM IN THE WORKS OF ANTHONY GIDDENS AND NORBERT ELIAS: A COMPARISON

    OpenAIRE

    Šņitņikovs, Aleksejs

    2017-01-01

    The purpose of the paper is to assess the arguments of the critique of functionalism by Anthony Giddens and Norbert Elias. After being subject to severe criticism, terminology of functionalism is still a part of the lexicon of social scientists nowadays. Functionalist reasoning and concepts of functionalism are used in sociology, political science and economics, even though often without full awareness of its theoretical implications. Recent revival of interest in the works by Elias is connec...

  5. Working memory assessment in schizophrenia and its correlation with executive functions ability.

    Science.gov (United States)

    Berberian, Arthur A; Trevisan, Bruna T; Moriyama, Tais S; Montiel, José M; Oliveira, José Ari C; Seabra, Alessandra G

    2009-09-01

    Working memory impairment is common in schizophrenia and is possibly a cause of multiple features of the disorder. However few studies have replicated such findings of impairment patterns in Brazilian samples. The main target of this study was to assess auditory and visual working memory in patients with schizophrenia, to assess if they work as separate systems, and to correlate working memory deficits with executive functions. Twenty subjects with schizophrenia and twenty healthy subjects matched by gender, age, and schooling have participated. The abilities assessed were auditory and visual working memory, selective attention, inhibitory control, cognitive flexibility, and planning. Patients showed declines in all measures evaluated, except for a measure reaction time of inhibitory control. Auditory working memory was correlated to selective attention, inhibition, flexibility and planning while Visual working memory to planning and flexibility. The present study suggests that working memory and executive functions deficits are present in patients with schizophrenia in the Brazilian sample evaluated. Alterations in executive functions may lead to incapacity of operation of processes of working memory. These findings may contribute to delineate and develop new strategies of schizophrenia treatment in the Brazilian population.

  6. Primary role of electron work function for evaluation of nanostructured titania implant surface against bacterial infection

    Energy Technology Data Exchange (ETDEWEB)

    Golda-Cepa, M., E-mail: golda@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Syrek, K. [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Brzychczy-Wloch, M. [Department of Bacteriology, Microbial Ecology and Parasitology, Jagiellonian University Medical College, Czysta 18, 31-121 Krakow (Poland); Sulka, G.D. [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Kotarba, A., E-mail: kotarba@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland)

    2016-09-01

    The electron work function as an essential descriptor for the evaluation of metal implant surfaces against bacterial infection is identified for the first time. Its validity is demonstrated on Staphylococcus aureus adhesion to nanostructured titania surfaces. The established correlation: work function–bacteria adhesion is of general importance since it can be used for direct evaluation of any electrically conductive implant surfaces. - Highlights: • The correlation between work function and bacteria adhesion was discovered. • The discovered correlation is rationalized in terms of electrostatic bacteria–surface repulsion. • The results provide basis for the simple evaluation of implant surfaces against infection.

  7. Primary role of electron work function for evaluation of nanostructured titania implant surface against bacterial infection

    International Nuclear Information System (INIS)

    Golda-Cepa, M.; Syrek, K.; Brzychczy-Wloch, M.; Sulka, G.D.; Kotarba, A.

    2016-01-01

    The electron work function as an essential descriptor for the evaluation of metal implant surfaces against bacterial infection is identified for the first time. Its validity is demonstrated on Staphylococcus aureus adhesion to nanostructured titania surfaces. The established correlation: work function–bacteria adhesion is of general importance since it can be used for direct evaluation of any electrically conductive implant surfaces. - Highlights: • The correlation between work function and bacteria adhesion was discovered. • The discovered correlation is rationalized in terms of electrostatic bacteria–surface repulsion. • The results provide basis for the simple evaluation of implant surfaces against infection.

  8. Functional connectivity among multi-channel EEGs when working memory load reaches the capacity.

    Science.gov (United States)

    Zhang, Dan; Zhao, Huipo; Bai, Wenwen; Tian, Xin

    2016-01-15

    Evidence from behavioral studies has suggested a capacity existed in working memory. As the concept of functional connectivity has been introduced into neuroscience research in the recent years, the aim of this study is to investigate the functional connectivity in the brain when working memory load reaches the capacity. 32-channel electroencephalographs (EEGs) were recorded for 16 healthy subjects, while they performed a visual working memory task with load 1-6. Individual working memory capacity was calculated according to behavioral results. Short-time Fourier transform was used to determine the principal frequency band (theta band) related to working memory. The functional connectivity among EEGs was measured by the directed transform function (DTF) via spectral Granger causal analysis. The capacity was 4 calculated from the behavioral results. The power was focused in the frontal midline region. The strongest connectivity strengths of EEG theta components from load 1 to 6 distributed in the frontal midline region. The curve of DTF values vs load numbers showed that DTF increased from load 1 to 4, peaked at load 4, then decreased after load 4. This study finds that the functional connectivity between EEGs, described quantitatively by DTF, became less strong when working memory load exceeded the capacity. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Selective Attention, Working Memory, and Executive Function as Potential Independent Sources of Cognitive Dysfunction in Schizophrenia.

    Science.gov (United States)

    Gold, James M; Robinson, Benjamin; Leonard, Carly J; Hahn, Britta; Chen, Shuo; McMahon, Robert P; Luck, Steven J

    2017-11-11

    People with schizophrenia demonstrate impairments in selective attention, working memory, and executive function. Given the overlap in these constructs, it is unclear if these represent distinct impairments or different manifestations of one higher-order impairment. To examine this question, we administered tasks from the basic cognitive neuroscience literature to measure visual selective attention, working memory capacity, and executive function in 126 people with schizophrenia and 122 healthy volunteers. Patients demonstrated deficits on all tasks with the exception of selective attention guided by strong bottom-up inputs. Although the measures of top-down control of selective attention, working memory, and executive function were all intercorrelated, several sources of evidence indicate that working memory and executive function are separate sources of variance. Specifically, both working memory and executive function independently contributed to the discrimination of group status and independently accounted for variance in overall general cognitive ability as assessed by the MATRICS battery. These two cognitive functions appear to be separable features of the cognitive impairments observed in schizophrenia. © The Author 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. Does polycystic ovary syndrome affect cognition? A functional magnetic resonance imaging study exploring working memory.

    Science.gov (United States)

    Soleman, Remi S; Kreukels, Baudewijntje P C; Veltman, Dick J; Cohen-Kettenis, Peggy T; Hompes, Peter G A; Drent, Madeleine L; Lambalk, Cornelis B

    2016-05-01

    To study effects of overexposure to androgens and subsequent antiandrogenic treatment on brain activity during working memory processes in women with polycystic ovary syndrome (PCOS). In this longitudinal study, working memory function was evaluated with the use of functional magnetic resonance imaging (MRI) in women with PCOS before and after antiandrogenic treatment. Department of reproductive medicine, university medical center. Fourteen women with PCOS and with hyperandrogenism and 20 healthy control women without any features of PCOS or other hormonal disorders. Antiandrogenic hormone treatment. Functional MRI response during a working memory task. At baseline women with PCOS showed more activation than the control group within the right superior parietal lobe and the inferior parietal lobe during task (all memory conditions). Task performance (speed and accuracy) did not differ between the groups. After antiandrogenic treatment the difference in overall brain activity between the groups disappeared and accuracy in the high memory load condition of the working memory task increased in women with PCOS. Women with PCOS may need additional neural resources during a working memory task compared with women without PCOS, suggesting less efficient executive functioning. This inefficiency may have effects on daily life functioning of women with PCOS. Antiandrogenic treatment appears to have a beneficial effect on this area of cognitive functioning. NTR2493. Copyright © 2016. Published by Elsevier Inc.

  11. Microscopic work function anisotropy and surface chemistry of 316L stainless steel using photoelectron emission microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, N., E-mail: nick.barrett@cea.fr [CEA, IRAMIS, SPEC, LENSIS, F-91191 Gif-sur-Yvette (France); Renault, O. [CEA, LETI, Minatec Campus, F-38054 Grenoble Cedex 09 (France); Lemaître, H. [Université de Cergy-Pontoise, Rue d’Eragny, Neuville sur Oise, 95 031 Cergy-Pontoise (France); Surface Dynamics Laboratory, Institut for Fysik og Astronomi Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C (Denmark); Bonnaillie, P. [CEA, DEN, DANS, DMN, SRMP, F-91191 Gif-sur-Yvette (France); Barcelo, F. [CEA, DEN, DANS, DMN, SRMA, LA2M, F-91191 Gif-sur-Yvette (France); Miserque, F. [CEA, DEN, DANS, DPC, SCCME, LECA, F-91191 Gif-sur-Yvette (France); Wang, M.; Corbel, C. [Laboratoire des Solides Irradis, Ecole Polytechnique, route de Saclay, F-91128 Palaiseau (France)

    2014-08-15

    Highlights: • PEEM and EBSD study of spatial variations in local work function of 316L steel. • Correlation between work function and crystal grain orientation at the surface of 316L steel. • Spatially resolved chemistry of residual oxide layer. - Abstract: We have studied the variation in the work function of the surface of sputtered cleaned 316L stainless steel with only a very thin residual oxide surface layer as a function of grain orientation using X-ray photoelectron emission microscopy (XPEEM) and Electron Backscattering Diffraction. The grains are mainly oriented [1 1 1] and [1 0 1]. Four distinct work function values spanning a 150 meV energy window are measured. Grains oriented [1 1 1] have a higher work function than those oriented [1 0 1]. From core level XPEEM we deduce that all grain surfaces are Cr enriched and Ni depleted whereas the Cr/Fe ratio is similar for all grains. The [1 1 1] oriented grains show evidence for a Cr{sub 2}O{sub 3} surface oxide and a higher concentration of defective oxygen sites.

  12. Conceptual foundation for measures of physical function and behavioral health function for Social Security work disability evaluation.

    Science.gov (United States)

    Marfeo, Elizabeth E; Haley, Stephen M; Jette, Alan M; Eisen, Susan V; Ni, Pengsheng; Bogusz, Kara; Meterko, Mark; McDonough, Christine M; Chan, Leighton; Brandt, Diane E; Rasch, Elizabeth K

    2013-09-01

    Physical and mental impairments represent the 2 largest health condition categories for which workers receive Social Security disability benefits. Comprehensive assessment of physical and mental impairments should include aspects beyond medical conditions such as a person's underlying capabilities as well as activity demands relevant to the context of work. The objective of this article is to describe the initial conceptual stages of developing new measurement instruments of behavioral health and physical functioning relevant for Social Security work disability evaluation purposes. To outline a clear conceptualization of the constructs to be measured, 2 content models were developed using structured and informal qualitative approaches. We performed a structured literature review focusing on work disability and incorporating aspects of the International Classification of Functioning, Disability and Health as a unifying taxonomy for framework development. Expert interviews provided advice and consultation to enhance face validity of the resulting content models. The content model for work-related behavioral health function identifies 5 major domains: (1) behavior control, (2) basic interactions, (3) temperament and personality, (4) adaptability, and (5) workplace behaviors. The content model describing physical functioning includes 3 domains: (1) changing and maintaining body position, (2) whole-body mobility, and (3) carrying, moving, and handling objects. These content models informed subsequent measurement properties including item development and measurement scale construction, and provided conceptual coherence guiding future empirical inquiry. The proposed measurement approaches show promise to comprehensively and systematically assess physical and behavioral health functioning relevant to work. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  13. Adsorption of nitrogen on W(100): effect of surface disorder on the work function change

    International Nuclear Information System (INIS)

    Singh-Bofarai, S.P.; King, D.A.

    1976-01-01

    At room temperature nitrogen adsorption causes the work function of the (100) plane of tungsten to decrease by approximately 0.6 eV, while on all other planes the work function is increased, albeit by as little as 0.03 eV on the (110) plane. Surface disorder can readily be created by the vapour deposition of W onto a clean, annealed W single crystal surface, and in the present work this technique was used to shadow a W field emission tip with disordered W atoms so as to observe the effect of surface disorder on the work function change due to nitrogen adsorption, particularly at the (100) poles of the tip. (Auth.)

  14. Is functional integration of resting state brain networks an unspecific biomarker for working memory performance?

    Science.gov (United States)

    Alavash, Mohsen; Doebler, Philipp; Holling, Heinz; Thiel, Christiane M; Gießing, Carsten

    2015-03-01

    Is there one optimal topology of functional brain networks at rest from which our cognitive performance would profit? Previous studies suggest that functional integration of resting state brain networks is an important biomarker for cognitive performance. However, it is still unknown whether higher network integration is an unspecific predictor for good cognitive performance or, alternatively, whether specific network organization during rest predicts only specific cognitive abilities. Here, we investigated the relationship between network integration at rest and cognitive performance using two tasks that measured different aspects of working memory; one task assessed visual-spatial and the other numerical working memory. Network clustering, modularity and efficiency were computed to capture network integration on different levels of network organization, and to statistically compare their correlations with the performance in each working memory test. The results revealed that each working memory aspect profits from a different resting state topology, and the tests showed significantly different correlations with each of the measures of network integration. While higher global network integration and modularity predicted significantly better performance in visual-spatial working memory, both measures showed no significant correlation with numerical working memory performance. In contrast, numerical working memory was superior in subjects with highly clustered brain networks, predominantly in the intraparietal sulcus, a core brain region of the working memory network. Our findings suggest that a specific balance between local and global functional integration of resting state brain networks facilitates special aspects of cognitive performance. In the context of working memory, while visual-spatial performance is facilitated by globally integrated functional resting state brain networks, numerical working memory profits from increased capacities for local processing

  15. Work function reduction by a redox-active organometallic sandwich complex

    KAUST Repository

    Hyla, Alexander; Winget, Paul; Li, Hong; Risko, Chad; Bredas, Jean-Luc

    2016-01-01

    We have investigated, at the density functional theory level, the geometric and electronic structures of the pentamethyliridocene (IrCpCp*) monomer and dimer adsorbed on the Au(111) and indium tin oxide (ITO) (222) surfaces, as well as their impact on the work functions. Our calculations show that the adsorption of a monomer lowers the work function of ITO(222) by 1.2 eV and Au(111) by 1.2–1.3 eV. The main origin for this reduction is the formation of an interface dipole between the monomer and the substrate via charge transfer. Dimer adsorption as well as adsorption of possible byproducts formed from dimer bond-cleavage in solution, show a lesser ability to lower the work function. © 2016 Elsevier B.V.

  16. An orbital-overlap model for minimal work functions of cesiated metal surfaces

    International Nuclear Information System (INIS)

    Chou, Sharon H; Bargatin, Igor; Howe, Roger T; Voss, Johannes; Vojvodic, Aleksandra; Abild-Pedersen, Frank

    2012-01-01

    We introduce a model for the effect of cesium adsorbates on the work function of transition metal surfaces. The model builds on the classical point-dipole equation by adding exponential terms that characterize the degree of orbital overlap between the 6s states of neighboring cesium adsorbates and its effect on the strength and orientation of electric dipoles along the adsorbate-substrate interface. The new model improves upon earlier models in terms of agreement with the work function-coverage curves obtained via first-principles calculations based on density functional theory. All the cesiated metal surfaces have optimal coverages between 0.6 and 0.8 monolayers, in accordance with experimental data. Of all the cesiated metal surfaces that we have considered, tungsten has the lowest minimum work function, also in accordance with experiments.

  17. Work function reduction by a redox-active organometallic sandwich complex

    KAUST Repository

    Hyla, Alexander

    2016-07-14

    We have investigated, at the density functional theory level, the geometric and electronic structures of the pentamethyliridocene (IrCpCp*) monomer and dimer adsorbed on the Au(111) and indium tin oxide (ITO) (222) surfaces, as well as their impact on the work functions. Our calculations show that the adsorption of a monomer lowers the work function of ITO(222) by 1.2 eV and Au(111) by 1.2–1.3 eV. The main origin for this reduction is the formation of an interface dipole between the monomer and the substrate via charge transfer. Dimer adsorption as well as adsorption of possible byproducts formed from dimer bond-cleavage in solution, show a lesser ability to lower the work function. © 2016 Elsevier B.V.

  18. Electrochemical treatment of tannery wastewater using DSA electrodes

    International Nuclear Information System (INIS)

    Costa, Carla Regina; Botta, Clarice M.R.; Espindola, Evaldo L.G.; Olivi, Paulo

    2008-01-01

    In this work we studied the electrochemical treatment of a tannery wastewater using dimensionally stable anodes (DSA) containing tin, iridium, ruthenium, and titanium. The electrodes were prepared by thermal decomposition of the polymeric precursors. The electrolyses were performed under galvanostatic conditions, at room temperature. Effects of the oxide composition, current density, and effluent conductivity were investigated, and the current efficiency was calculated as a function of the time for the performed electrolyses. Results showed that all the studied electrodes led to a decrease in the content of both total phenolic compounds and total organic carbon (TOC), as well as lower absorbance in the UV-vis region. Toxicity tests using Daphnia similis demonstrated that the electrochemical treatment reduced the wastewater toxicity. The use of DSA type electrodes in the electrochemical treatment of tannery wastewater proved to be useful since it can promote a decrease in total phenolic compounds, TOC, absorbance, and toxicity

  19. Electrochemical treatment of tannery wastewater using DSA electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Carla Regina [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, CEP 14049-901 Ribeirao Preto, SP (Brazil); Botta, Clarice M.R.; Espindola, Evaldo L.G. [Nucleo de Estudos em Ecossistemas Aquaticos, Centro de Recursos Hidricos e Ecologia Aplicada, Escola de Engenharia de Sao Carlos, Universidade de Sao Paulo, CP 292, CEP 13560-970 Sao Carlos, SP (Brazil); Olivi, Paulo [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, CEP 14049-901 Ribeirao Preto, SP (Brazil)], E-mail: olivip@ffclrp.usp.br

    2008-05-01

    In this work we studied the electrochemical treatment of a tannery wastewater using dimensionally stable anodes (DSA) containing tin, iridium, ruthenium, and titanium. The electrodes were prepared by thermal decomposition of the polymeric precursors. The electrolyses were performed under galvanostatic conditions, at room temperature. Effects of the oxide composition, current density, and effluent conductivity were investigated, and the current efficiency was calculated as a function of the time for the performed electrolyses. Results showed that all the studied electrodes led to a decrease in the content of both total phenolic compounds and total organic carbon (TOC), as well as lower absorbance in the UV-vis region. Toxicity tests using Daphnia similis demonstrated that the electrochemical treatment reduced the wastewater toxicity. The use of DSA type electrodes in the electrochemical treatment of tannery wastewater proved to be useful since it can promote a decrease in total phenolic compounds, TOC, absorbance, and toxicity.

  20. Effects of Flexible Dry Electrode Design on Electrodermal Activity Stimulus Response Detection.

    Science.gov (United States)

    Haddad, Peter A; Servati, Amir; Soltanian, Saeid; Ko, Frank; Servati, Peyman

    2017-12-01

    The focus of this research is to evaluate the effects of design parameters including surface area, distance between and geometry of dry flexible electrodes on electrodermal activity (EDA) stimulus response detection. EDA is a result of the autonomic nervous system being stimulated, which causes sweat and changes the electrical characteristics of the skin. Standard silver/silver chloride (Ag/AgCl) EDA electrodes are rigid and lack conformability in contact with skin. In this study, flexible dry Ag/AgCl EDA electrodes were fabricated on a compliant substrate, used to monitor EDA stimulus responses and compared to results simultaneously collected by rigid dry Ag/AgCl electrodes. A repeatable fabrication process for flexible Ag/AgCl electrodes has been established. Surface area, distance between and geometry of electrodes are shown to affect the detectability of the EDA response and the minimum number of sweat glands to be covered by the electrodes has been estimated at 140, or more, in order to maintain functionality. The optimal flexible EDA electrode is a serpentine design with a 0.15 cm 2 surface area and a 0.20 cm distance with an average Pearson correlation coefficient of . Fabrication of flexible electrodes is described and an understanding of the effects of electrode designs on the EDA stimulus response detection has been established and is potentially related to the coverage of sweat glands. This work presents a novel systematic approach to understand the effects of electrode designs on monitoring EDA which is of importance for the design of wearable EDA monitoring devices.

  1. Cyclovoltammetric acetylcholinesterase activity assay after inhibition and subsequent reactivation by using a glassy carbon electrode modified with palladium nanorods composited with functionalized C60 fullerene

    International Nuclear Information System (INIS)

    Ye, Cui; Zhong, Xia; Chai, Yaqin; Yuan, Ruo; Wang, Min-Qiang

    2016-01-01

    A glassy carbon electrode (GCE) was modified with a nanocomposite consisting of tetraoctylammonium bromide (TOAB), C 60 fullerene, and palladium nanorods (PdNRs). The PdNRs were hydrothermally prepared and had a typical width of 20 ± 2 nm. The nanocomposite forms stable films on the GCE and exhibits a reversible redox pair for the C 60 /C 60 − system while rendering the surface to be positively charged. The modified GCE was applied to fabricate an electrochemical biosensor for detecting acetylcholinesterase (AChE) by measurement of the amount of thiocholine formed from acetylthiocholine, best at a working voltage of −0.19 V (vs. SCE). The detection scheme is based on (a) measurement of the activity of ethyl paraoxon-inhibited AChE, and (b) measurement of AChE activity after reactivation with pralidoxime (2-PAM). Compared to the conventional methods using acetylthiocholine as a substrate, the dual method presented here provides data on the AChE activity after inhibition and subsequent reactivation, thereby yielding credible data on reactivated enzyme activity. The linear analytical range for AChE activity extends from 2.5 U L −1 to 250 kU·L −1 , and the detection limit is 0.83 U L −1 . (author)

  2. Concept and Development of an Electronic Framework Intended for Electrode and Surrounding Environment Characterization In Vivo

    Directory of Open Access Journals (Sweden)

    Stefan B. Rieger

    2016-12-01

    Full Text Available There has been substantial progress over the last decade towards miniaturizing implantable microelectrodes for use in Active Implantable Medical Devices (AIMD. Compared to the rapid development and complexity of electrode miniaturization, methods to monitor and assess functional integrity and electrical functionality of these electrodes, particularly during long term stimulation, have not progressed to the same extent. Evaluation methods that form the gold standard, such as stimulus pulse testing, cyclic voltammetry and electrochemical impedance spectroscopy, are either still bound to laboratory infrastructure (impractical for long term in vivo experiments or deliver no comprehensive insight into the material’s behaviour. As there is a lack of cost effective and practical predictive measures to understand long term electrode behaviour in vivo, material investigations need to be performed after explantation of the electrodes. We propose the analysis of the electrode and its environment in situ, to better understand and correlate the effects leading to electrode failure. The derived knowledge shall eventually lead to improved electrode designs, increased electrode functionality and safety in clinical applications. In this paper, the concept, design and prototyping of a sensor framework used to analyse the electrode’s behaviour and to monitor diverse electrode failure mechanisms, even during stimulation pulses, is presented. We focused on the electronic circuitry and data acquisition techniques required for a conceptual multi-sensor system. Functionality of single modules and a prototype framework have been demonstrated, but further work is needed to convert the prototype system into an implantable device. In vitro studies will be conducted first to verify sensor performance and reliability.

  3. Biomass-derived functional porous carbons as novel electrode material for the practical detection of biomolecules in human serum and snail hemolymph

    Science.gov (United States)

    Veeramani, Vediyappan; Madhu, Rajesh; Chen, Shen-Ming; Lou, Bih-Show; Palanisamy, Jayabal; Vasantha, Vairathevar Sivasamy

    2015-05-01

    The biomass-derived activated carbons (ACs) have been prepared with high surface areas up to 793 m2 g-1 is by ZnCl2 activation at three different temperatures, viz. AC700, AC800, and AC900. The AC samples were characterized by a variety of analytical and spectroscopy techniques. The as-synthesized ACs were adopted for the simultaneous electrochemical detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). For comparison, reduced graphene oxide (RGO) was employed for the proposed sensor. The high surface area, modulated pore size and the presence of oxygen surface functional groups like heteroatoms (83.427% C, 1.085% N, 0.383% S, and 0.861% H) in the biomass-derived AC is found to be responsible for the excellent catalytic activities of biomolecules. Fascinatingly, the facile sensor further used to detect biomolecules levels in the snail hemolymph and human blood serum. Notably, the obtained analytical parameters for the biomolecules detection over the AC modified GCE, outperforming several carbon-based modified electrodes in literatures.

  4. All-phosphorus flexible devices with non-collinear electrodes: a first principles study.

    Science.gov (United States)

    Li, Junjun; Ruan, Lufeng; Wu, Zewen; Zhang, Guiling; Wang, Yin

    2018-03-07

    With the continuous expansion of the family of two-dimensional (2D) materials, flexible electronics based on 2D materials have quickly emerged. Theoretically, predicting the transport properties of the flexible devices made up of 2D materials using first principles is of great importance. Using density functional theory combined with the non-equilibrium Green's function formalism, we calculated the transport properties of all-phosphorus flexible devices with non-collinear electrodes, and the results predicted that the device with compressed metallic phosphorene electrodes sandwiching a P-type semiconducting phosphorene shows a better and robust conducting behavior against the bending of the semiconducting region when the angle between the two electrodes is less than 45°, which indicates that this system is very promising for flexible electronics. The calculation of a quantum transport system with non-collinear electrodes demonstrated in this work will provide more interesting information on mesoscopic material systems and related devices.

  5. Drawing a dog: The role of working memory and executive function.

    Science.gov (United States)

    Panesi, Sabrina; Morra, Sergio

    2016-12-01

    Previous research suggests that young children draw animals by adapting their scheme for the human figure. This can be considered an early form of drawing flexibility. This study investigated preschoolers' ability to draw a dog that is different from the human figure. The role of working memory capacity and executive function was examined. The participants were 123 children (36-73 months old) who were required to draw both a person and a dog. The dog figure was scored on a list of features that could render it different from the human figure. Regression analyses showed that both working memory capacity and executive function predicted development in the dog drawing; the dog drawing score correlated with working memory capacity and executive function, even partialling out age, motor coordination, and drawing ability (measured with Goodenough's Draw-a-Man test). These results suggest that both working memory capacity and executive function play an important role in the early development of drawing flexibility. The implications regarding executive functions and working memory are also discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Predictive value and construct validity of the work functioning screener-healthcare (WFS-H)

    Science.gov (United States)

    Boezeman, Edwin J.; Nieuwenhuijsen, Karen; Sluiter, Judith K.

    2016-01-01

    Objectives: To test the predictive value and convergent construct validity of a 6-item work functioning screener (WFS-H). Methods: Healthcare workers (249 nurses) completed a questionnaire containing the work functioning screener (WFS-H) and a work functioning instrument (NWFQ) measuring the following: cognitive aspects of task execution and general incidents, avoidance behavior, conflicts and irritation with colleagues, impaired contact with patients and their family, and level of energy and motivation. Productivity and mental health were also measured. Negative and positive predictive values, AUC values, and sensitivity and specificity were calculated to examine the predictive value of the screener. Correlation analysis was used to examine the construct validity. Results: The screener had good predictive value, since the results showed that a negative screener score is a strong indicator of work functioning not hindered by mental health problems (negative predictive values: 94%-98%; positive predictive values: 21%-36%; AUC:.64-.82; sensitivity: 42%-76%; and specificity 85%-87%). The screener has good construct validity due to moderate, but significant (pvalue and good construct validity. Its score offers occupational health professionals a helpful preliminary insight into the work functioning of healthcare workers. PMID:27010085

  7. Correlation of H- production and the work function of a surface in a hydrogen plasma

    International Nuclear Information System (INIS)

    Wada, M.

    1983-01-01

    Surface-plasma negative hydrogen ion sources are being developed as possible parts for future netural beam systems. In these ion sources, negative hydrogen ions (H - ) are produced at low work function metal surfaces immersed in hydrogen plasmas. To investigate the correlation between the work function and the H-production at the surface with a condition similar to the one in the actual plasma ion source, these two parameters were simultaneously measured in the hydrogen plasma environment. The photoelectron emission currents from Mo and Cu surfaces in a cesiated hydrogen discharge were measured in the photon energy range from 1.45 to 4.14 eV, to determine the work function based on Fowler's theory. A small magnetic line cusp plasma container was specially designed to minimize the plasma noise and to realize the efficient collection of incident light onto the target. The photelectron current was detected phase sensitively and could be measured with reasonable accuracy up to about 5 x 10 11 cm -3 of the plasma electron density. As Cs density was increased in the hydrogen discharge, the work function decreased until it reached a minimum value. This value of the lowest work function was approximately 1.4 eV for both Mo and Cu surfaces, and the detected total H - current was a maximum at this condition

  8. Predictive value and construct validity of the work functioning screener-healthcare (WFS-H).

    Science.gov (United States)

    Boezeman, Edwin J; Nieuwenhuijsen, Karen; Sluiter, Judith K

    2016-05-25

    To test the predictive value and convergent construct validity of a 6-item work functioning screener (WFS-H). Healthcare workers (249 nurses) completed a questionnaire containing the work functioning screener (WFS-H) and a work functioning instrument (NWFQ) measuring the following: cognitive aspects of task execution and general incidents, avoidance behavior, conflicts and irritation with colleagues, impaired contact with patients and their family, and level of energy and motivation. Productivity and mental health were also measured. Negative and positive predictive values, AUC values, and sensitivity and specificity were calculated to examine the predictive value of the screener. Correlation analysis was used to examine the construct validity. The screener had good predictive value, since the results showed that a negative screener score is a strong indicator of work functioning not hindered by mental health problems (negative predictive values: 94%-98%; positive predictive values: 21%-36%; AUC:.64-.82; sensitivity: 42%-76%; and specificity 85%-87%). The screener has good construct validity due to moderate, but significant (ppredictive value and good construct validity. Its score offers occupational health professionals a helpful preliminary insight into the work functioning of healthcare workers.

  9. Work function and surface stability of tungsten-based thermionic electron emission cathodes

    Science.gov (United States)

    Jacobs, Ryan; Morgan, Dane; Booske, John

    2017-11-01

    Materials that exhibit a low work function and therefore easily emit electrons into vacuum form the basis of electronic devices used in applications ranging from satellite communications to thermionic energy conversion. W-Ba-O is the canonical materials system that functions as the thermionic electron emitter commercially used in a range of high-power electron devices. However, the work functions, surface stability, and kinetic characteristics of a polycrystalline W emitter surface are still not well understood or characterized. In this study, we examined the work function and surface stability of the eight lowest index surfaces of the W-Ba-O system using density functional theory methods. We found that under the typical thermionic cathode operating conditions of high temperature and low oxygen partial pressure, the most stable surface adsorbates are Ba-O species with compositions in the range of Ba0.125O-Ba0.25O per surface W atom, with O passivating all dangling W bonds and Ba creating work function-lowering surface dipoles. Wulff construction analysis reveals that the presence of O and Ba significantly alters the surface energetics and changes the proportions of surface facets present under equilibrium conditions. Analysis of previously published data on W sintering kinetics suggests that fine W particles in the size range of 100-500 nm may be at or near equilibrium during cathode synthesis and thus may exhibit surface orientation fractions well described by the calculated Wulff construction.

  10. Sleep disturbances and reduced work functioning in depressive or anxiety disorders.

    Science.gov (United States)

    van Mill, Josine G; Vogelzangs, Nicole; Hoogendijk, Witte J G; Penninx, Brenda W J H

    2013-11-01

    We aimed to examine the associations between sleep disturbances and work functioning in an epidemiologic cohort study in subjects with or without depressive or anxiety disorders. There were 707 subjects included in our analyses with depressive or anxiety disorders and 728 subjects without current depressive or anxiety disorders. Insomnia was defined as a score ≥9 using the Insomnia Rating Scale. Self-reported sleep duration was categorized in short, normal, and long (≤6, 7-9, and ≥10 h, respectively). Work absenteeism was defined as none, short (≤2 weeks), or long (>2 weeks). Work performance was defined as not impaired, reduced, or impaired. Logistic regression analyses were performed to examine the associations of sleep disturbances with work functioning. In subjects with psychopathology, insomnia and short sleep duration were significantly associated with impaired work performance (odds ratio [OR] for insomnia, 2.20; [95% confidence interval {CI}, 1.50-3.22]; OR for short sleep, 2.54 [95% CI, 1.66-3.88] compared to normal sleep duration). Insomnia (OR, 2.48 [95% CI, 1.67-3.69]) and short sleep duration (OR, 1.85 [95% CI, 1.23-2.78]) also were associated with long-term absenteeism. These findings remained the same after considering clinical characteristics including medication use and symptom severity. In subjects without psychopathology, no significant associations were found between insomnia and short sleep duration on work functioning after considering subthreshold depression symptoms. In subjects with psychopathology, sleep disturbances were negatively associated with work functioning, independent of disorder severity and use of psychotropic medication. Further research is needed to determine if treatment of sleep disturbances in subjects with psychopathology improves work functioning. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. The impact of night-shift work on platelet function in healthy medical staff.

    Science.gov (United States)

    Nakao, Tomoko; Yasumoto, Atsushi; Tokuoka, Suzumi; Kita, Yoshihiro; Kawahara, Takuya; Daimon, Masao; Yatomi, Yutaka

    2018-04-18

    Rotating shift work has been reported to increase the risk of cardiovascular diseases. Vascular endothelial dysfunction and platelet activation are among the leading causes of thrombus formation in patients with myocardial infarction or stroke. Endothelial function has been shown to be impaired immediately after night-shift work; however, it is not known whether platelets are also activated. The aim of this study was to investigate the acute impact of night-shift work on platelet function. This observational study included 11 healthy medical staff members (seven women, median age 32 years). We examined each subject's platelet aggregation rates and the serum concentrations of eicosanoid mediators after night-shift work and on day-shift work without preceding night-shift work (baseline). Platelet aggregation did not differ from baseline levels after night-shift work. However, serum cyclooxygenase (COX)-metabolized eicosanoid mediators, particularly thromboxane (Tx) B 2 (a stable metabolite of TxA 2 and the most important marker of platelet activation), were significantly higher after the night-shift than at baseline (median 65.3 vs 180.4 ng/ml). Although platelet aggregation did not increase, there was an increase in serum COX-metabolized eicosanoid mediators such as TxB 2 in healthy medical staff after night-shift work. This platelet hypersensitivity may be one of the mechanisms underlying the significant association between night-shift work and adverse cardiovascular outcomes.

  12. Adsorption mechanisms of lithium oxides (Li{sub x}O{sub 2}) on a graphene-based electrode: A density functional theory approach

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hye [Department of Organic Material Science and Engineering, Pusan National University, 2, Busandaehak-ro 63beon gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Kang, Sung Gu [Office of Strategic Foresight, Korea Institute of S& T Evaluation and Planning (KISTEP), 68, Mabang-ro, Seocho-gu, Seoul 137-717 (Korea, Republic of); Moon, Hye Sook [Department of Organic Material Science and Engineering, Pusan National University, 2, Busandaehak-ro 63beon gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Park, Hyun [Global Core Research Center for Ships and Offshore Plants (GCRC-SOP), Pusan National University, 2 Busandaehak-ro 63beon gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Kim, Il Tae, E-mail: itkim@gachon.ac.kr [Department of Chemical and Biological Engineering, Gachon University, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of); Lee, Seung Geol, E-mail: seunggeol.lee@pusan.ac.kr [Department of Organic Material Science and Engineering, Pusan National University, 2, Busandaehak-ro 63beon gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

    2015-10-01

    Highlights: • Lithium oxide (Li{sub x}O{sub 2}) adsorption mechanisms onto a graphene-based electrode. • The adsorption energy of LiO{sub 2} on graphene (−0.450 eV). • Li{sub 2}O{sub 2} revealed that the parallel configurations (−0.630 to −0.611 eV) were more stable. • The energy bands in the Li{sub 2}O{sub 2}@graphene system were shifted down. - Abstract: We computationally modeled the adsorptive behavior of O{sub 2}, Li, LiO{sub 2}, and Li{sub 2}O{sub 2} on graphene using density functional theory (DFT) in an effort to understand the mechanisms by which lithium oxides (Li{sub x}O{sub 2}) and oxygen reduction reaction (ORR) products adsorb onto graphene-based electrodes during lithium–air battery operation. O{sub 2} weakly adsorbed onto graphene with a binding energy of −0.111 to −0.089 eV, whereas Li strongly adsorbed onto graphene with relatively large binding energy of −1.079 to −0.774 eV. The LiO{sub 2} formation energy (−2.453 eV) was much lower than the LiO{sub 2} adsorption energy (−0.450 eV) on graphene, indicating that after Li and O{sub 2} had associated, LiO{sub 2} adsorbed onto the graphene surface. Among the various Li{sub 2}O{sub 2} adsorption configurations, the parallel configurations in which Li{sub 2}O{sub 2} was oriented along the graphene axis (−0.630 to −0.611 eV) were more favorable than the perpendicular configurations (−0.513 to −0.475 eV). Consequently, more charges were transferred from Li to graphene in a parallel orientation.

  13. Genetic predictor of working memory and prefrontal function in women with HIV.

    Science.gov (United States)

    Sundermann, Erin E; Bishop, Jeffrey R; Rubin, Leah H; Little, Deborah M; Meyer, Vanessa J; Martin, Eileen; Weber, Kathleen; Cohen, Mardge; Maki, Pauline M

    2015-02-01

    The Val158Met (rs4680) single-nucleotide polymorphism (SNP) of the catechol-O-methyltransferase gene (COMT) influences executive function and prefrontal function through its effect on dopamine (DA) metabolism. Both HIV and the Val allele of the Val158Met SNP are associated with compromised executive function and inefficient prefrontal function. The present study used behavioral and neuroimaging techniques to determine independent and interactive associations between HIV serostatus and COMT genotype on working memory and prefrontal function in women. For the behavioral study, 54 HIV-infected and 33 HIV-uninfected women completed the 0-, 1-, and 2-back conditions of the verbal N-back, a working memory test. For the imaging study, 36 women (23 HIV-infected, 13 HIV-uninfected) underwent functional magnetic resonance imaging (fMRI) assessments while completing the N-back task. HIV-infected women demonstrated significantly worse N-back performance compared with HIV-uninfected women (p women performed significantly worse than HIV-uninfected controls across N-back conditions (p working memory deficits and altered prefrontal function in HIV-infected individuals.

  14. Work stress, anthropometry, lung function, blood pressure, and blood-based biomarkers

    DEFF Research Database (Denmark)

    Magnusson Hanson, Linda L.; Westerlund, Hugo; Goldberg, Marcel

    2017-01-01

    -based biomarkers. Linear regression analyses before and after multivariable adjustment for age, socioeconomic status, depressive symptoms, health-related behaviours, and chronic conditions showed that work stress was associated with higher BMI, waist circumference, waist-hip ratio, alanine transaminase, white......Work stress is a risk factor for cardio-metabolic diseases, but few large-scale studies have examined the clinical profile of individuals with work stress. To address this limitation, we conducted a cross-sectional study including 43,593 working adults from a French population-based sample aged 18......–72 years (the CONSTANCES cohort). According to the Effort-Reward Imbalance model, work stress was defined as an imbalance between perceived high efforts and low rewards at work. A standardized health examination included measures of anthropometry, lung function, blood pressure and standard blood...

  15. Fabrication and Characterisation of Membrane-Based Gold Electrodes

    DEFF Research Database (Denmark)

    Bakmand, Tanya; Kwasny, Dorota; Dimaki, Maria

    2015-01-01

    This work presents a versatile, membrane based electrochemical sensor with thin film electrodes fabricated through Ebeam evaporation directly on porous materials (membranes). Here, the fabrication of the electrodes is described along with possible methods for integration in fluidic systems...

  16. Unique battery with a multi-functional, physicochemically active membrane separator/electrolyte-electrode monolith and a method making the same

    Science.gov (United States)

    Gerald II, Rex E.; Ruscic, Katarina J.; Sears, Devin N.; Smith, Luis J.; Klingler, Robert J.; Rathke, Jerome W.

    2012-07-24

    The invention relates to a unique battery having a physicochemically active membrane separator/electrolyte-electrode monolith and method of making the same. The Applicant's invented battery employs a physicochemically active membrane separator/electrolyte-electrode that acts as a separator, electrolyte, and electrode, within the same monolithic structure. The chemical composition, physical arrangement of molecules, and physical geometry of the pores play a role in the sequestration and conduction of ions. In one preferred embodiment, ions are transported via the ion-hoping mechanism where the oxygens of the Al2O3 wall are available for positive ion coordination (i.e. Li+). This active membrane-electrode composite can be adjusted to a desired level of ion conductivity by manipulating the chemical composition and structure of the pore wall to either increase or decrease ion conduction.

  17. Is Work-related Rumination Associated with deficits in Executive Functioning?

    Directory of Open Access Journals (Sweden)

    Mark Cropley

    2016-09-01

    Full Text Available AbstractWork-related rumination, that is, perseverative thinking about work during leisure time, has been associated with a range of negative health and wellbeing issues. The present paper examined the association between work-related rumination and cognitive processes centred around the theoretical construct of executive functioning. Executive functioning is an umbrella term for high level cognitive processes such as planning, working memory, inhibition, mental flexibility; and it underlies how people manage and regulate their goal directed behaviour. Three studies are reported. Study I, reports the results of a cross-sectional study of 240 employees, and demonstrates significant correlations between work-related rumination and three proxy measures of executive functioning: cognitive failures (.33, cognitive flexibility (-.24 and situational awareness at work (-.28. Study II (n = 939, expands on the findings from study 1 and demonstrates that workers reporting medium and high work-related rumination were 2.8 and 5 times, respectively, more likely to report cognitive failures relative to low ruminators. High ruminators also demonstrated greater difficulties with ‘lapses of attention’ (OR = 4.8, ‘lack of focus of attention’ (OR = 3.4, and ‘absent mindedness’ (OR = 4.3. The final study, examined the association between work-related rumination and executive functioning using interview data from 2460 full time workers. Workers were divided into tertiles low, medium and high. The findings showed that high work-related rumination was associated with deficits in starting (OR = 2.3 and finishing projects (OR = 2.4, fidgeting (OR = 1.9, memory (OR = 2.2, pursuing tasks in order (OR = 1.8, and feeling compelled to do things (OR = 2.0. It was argued that work-related rumination may not be related to work demands per se, but appears to be an executive functioning/control issue. Such findings are important for the design and delivery of

  18. Is Work-Related Rumination Associated with Deficits in Executive Functioning?

    Science.gov (United States)

    Cropley, Mark; Zijlstra, Fred R H; Querstret, Dawn; Beck, Sarah

    2016-01-01

    Work-related rumination, that is, perseverative thinking about work during leisure time, has been associated with a range of negative health and wellbeing issues. The present paper examined the association between work-related rumination and cognitive processes centerd around the theoretical construct of executive functioning. Executive functioning is an umbrella term for high level cognitive processes such as planning, working memory, inhibition, mental flexibility; and it underlies how people manage and regulate their goal directed behavior. Three studies are reported. Study I, reports the results of a cross-sectional study of 240 employees, and demonstrates significant correlations between work-related rumination and three proxy measures of executive functioning: cognitive failures (0.33), cognitive flexibility (-0.24), and situational awareness at work (-0.28). Study II ( n = 939), expands on the findings from study 1 and demonstrates that workers reporting medium and high work-related rumination were 2.8 and 5 times, respectively, more likely to report cognitive failures relative to low ruminators. High ruminators also demonstrated greater difficulties with 'lapses of attention' (OR = 4.8), 'lack of focus of attention' (OR = 3.4), and 'absent mindedness' (OR = 4.3). The final study, examined the association between work-related rumination and executive functioning using interview data from 2460 full time workers. Workers were divided into tertiles low, medium, and high. The findings showed that high work-related rumination was associated with deficits in starting (OR = 2.3) and finishing projects (OR = 2.4), fidgeting (OR = 1.9), memory (OR = 2.2), pursuing tasks in order (OR = 1.8), and feeling compelled to do things (OR = 2.0). It was argued that work-related rumination may not be related to work demands per se , but appears to be an executive functioning/control issue. Such findings are important for the design and delivery of intervention programes aimed

  19. Simultaneous measurements of work function and H‒ density including caesiation of a converter surface

    Science.gov (United States)

    Cristofaro, S.; Friedl, R.; Fantz, U.

    2017-08-01

    Negative hydrogen ion sources rely on the surface conversion of neutral atomic hydrogen and positive hydrogen ions to H-. The efficiency of this process depends on the actual work function of the converter surface. By introducing caesium into the source the work function decreases, enhancing the negative ion yield. In order to study the impact of the work function on the H- surface production at similar conditions to the ones in ion sources for fusion devices like ITER and DEMO, fundamental investigations are performed in a flexible laboratory experiment. The work function of the converter surface can be absolutely measured by photoelectric effect, while a newly installed cavity ring-down spectroscopy system (CRDS) measures the H- density. The CRDS is firstly tested and characterized by investigations on H- volume production. Caesiation of a stainless steel sample is then performed in vacuum and the plasma effect on the Cs layer is investigated also for long plasma-on times. A minimum work function of (1.9±0.1) eV is reached after some minutes of plasma treatment, resulting in a reduction by a value of 0.8 eV compared to vacuum measurements. The H- density above the surface is (2.1±0.5)×1015 m-3. With further plasma exposure of the caesiated surface, the work function increases up to 3.75 eV, due to the impinging plasma particles which gradually remove the Cs layer. As a result, the H- density decreases by a factor of at least 2.

  20. Electron work function of metallic surfaces, covered with by metal adatoms, and two-dimensional structure of adlayer

    International Nuclear Information System (INIS)

    Rudnitskij, L.A.

    1986-01-01

    Change in electron work function during metal adatom (Ti, W, Ag, Au) adsorption on different tungsten surfaces in ''polycrystalline'' and epitaxial types of adsorpted layers is studied. Calculational and experimental dependences of work function change on coating thickness are built

  1. The impact of bipolar disorder upon work functioning: a qualitative analysis.

    Science.gov (United States)

    Michalak, Erin E; Yatham, Lakshmi N; Maxwell, Victoria; Hale, Sandra; Lam, Raymond W

    2007-01-01

    One important but sometimes poorly-captured area of functioning concerns an individual's ability to work. Several quantitative studies have now indicated that bipolar disorder (BD) can have a severe, and often enduring, negative impact upon occupational functioning. While this data indicates that employment rates are relatively low in this patient population, it throws little light on the specific ways in which this complex psychiatric condition can affect work, or upon how these effects are subjectively interpreted by individuals with BD. In order to further elucidate the relationship between BD and work, we report here on a series of exploratory qualitative interviews undertaken to develop a disease-specific measure of quality of life in BD. We conducted 52 interviews with people with BD (n = 35), their caregivers (n = 5) and healthcare professionals (n = 12) identified by both convenience and purposive sampling. The affected sample came from a variety of employment situations, ranging between people with no employment history through to those in highly skilled, stable professional positions. Interviews were tape recorded, transcribed verbatim and analysed thematically. Respondents described the different ways in which the symptoms of depression and hypo/mania presented in the workplace. Five main themes emerged from the data: lack of continuity in work history, loss, illness management strategies in the workplace, stigma and disclosure in the workplace, and interpersonal problems at work. Patient outcome in BD has traditionally been determined by the assessment of clinical characteristics such as rates of relapse, hospitalization, or degree of symptom reduction. More recently, however, there has been increasing interest in expanding the assessment of outcome to include the measurement of indices such as functioning, a key facet of which relates to an individual's ability to work. The qualitative data obtained here highlights the often complex, varied and

  2. Working memory deficits in high-functioning adolescents with autism spectrum disorders: neuropsychological and neuroimaging correlates.

    Science.gov (United States)

    Barendse, Evelien M; Hendriks, Marc Ph; Jansen, Jacobus Fa; Backes, Walter H; Hofman, Paul Am; Thoonen, Geert; Kessels, Roy Pc; Aldenkamp, Albert P

    2013-06-04

    Working memory is a temporary storage system under attentional control. It is believed to play a central role in online processing of complex cognitive information and may also play a role in social cognition and interpersonal interactions. Adolescents with a disorder on the autism spectrum display problems in precisely these domains. Social impairments, communication difficulties, and repetitive interests and activities are core domains of autism spectrum disorders (ASD), and executive function problems are often seen throughout the spectrum. As the main cognitive theories of ASD, including the theory of mind deficit hypotheses, weak central coherence account, and the executive dysfunction theory, still fail to explain the broad spectrum of symptoms, a new perspective on the etiology of ASD is needed. Deficits in working memory are central to many theories of psychopathology, and are generally linked to frontal-lobe dysfunction. This article will review neuropsychological and (functional) brain imaging studies on working memory in adolescents with ASD. Although still disputed, it is concluded that within the working memory system specific problems of spatial working memory are often seen in adolescents with ASD. These problems increase when information is more complex and greater demands on working memory are made. Neuroimaging studies indicate a more global working memory processing or connectivity deficiency, rather than a focused deficit in the prefrontal cortex. More research is needed to relate these working memory difficulties and neuroimaging results in ASD to the behavioral difficulties as seen in individuals with a disorder on the autism spectrum.

  3. Emotion perception and executive functioning predict work status in euthymic bipolar disorder.

    Science.gov (United States)

    Ryan, Kelly A; Vederman, Aaron C; Kamali, Masoud; Marshall, David; Weldon, Anne L; McInnis, Melvin G; Langenecker, Scott A

    2013-12-15

    Functional recovery, including return to work, in Bipolar Disorder (BD) lags behind clinical recovery and may be incomplete when acute mood symptoms have subsided. We examined impact of cognition on work status and underemployment in a sample of 156 Euthymic-BD and 143 controls (HC) who were divided into working/not working groups. Clinical, health, social support, and personality data were collected, and eight cognitive factors were derived from a battery of neuropsychological tests. The HC groups outperformed the BD groups on seven of eight cognitive factors. The working-BD group outperformed the not working-BD group on 4 cognitive factors composed of tasks of emotion processing and executive functioning including processing speed and set shifting. Emotion processing and executive tasks were predictive of BD unemployment, after accounting for number of mood episodes. Four cognitive factors accounted for a significant amount of the variance in work status among the BD participants. Results indicate that patients with BD who are unemployed/unable to work exhibit greater difficulties processing emotional information and on executive tasks that comprise a set shifting or interference resolution component as compared to those who are employed, independent of other factors. These cognitive and affective factors are suggested as targets for treatment and/or accommodations. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. Work function of few layer graphene covered nickel thin films measured with Kelvin probe force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eren, B. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Material Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Gysin, U.; Marot, L., E-mail: Laurent.marot@unibas.ch; Glatzel, Th.; Steiner, R.; Meyer, E. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

    2016-01-25

    Few layer graphene and graphite are simultaneously grown on a ∼100 nm thick polycrystalline nickel film. The work function of few layer graphene/Ni is found to be 4.15 eV with a variation of 50 meV by local measurements with Kelvin probe force microscopy. This value is lower than the work function of free standing graphene due to peculiar electronic structure resulting from metal 3d-carbon 2p(π) hybridization.

  5. Improving the work function of the niobium surface of SRF cavities by plasma processing

    Science.gov (United States)

    Tyagi, P. V.; Doleans, M.; Hannah, B.; Afanador, R.; McMahan, C.; Stewart, S.; Mammosser, J.; Howell, M.; Saunders, J.; Degraff, B.; Kim, S.-H.

    2016-04-01

    An in situ plasma processing technique using chemically reactive oxygen plasma to remove hydrocarbons from superconducting radio frequency cavity surfaces at room temperature has been developed at the spallation neutron source, at Oak Ridge National Laboratory. To understand better the interaction between the plasma and niobium surface, surface studies on small samples were performed. In this article, we report the results from those surface studies. The results show that plasma processing removes hydrocarbons from top surface and improves the surface work function by 0.5-1.0 eV. Improving the work function of RF surface of cavities can help to improve their operational performance.

  6. The cost of misremembering: Inferring the loss function in visual working memory.

    Science.gov (United States)

    Sims, Chris R

    2015-03-04

    Visual working memory (VWM) is a highly limited storage system. A basic consequence of this fact is that visual memories cannot perfectly encode or represent the veridical structure of the world. However, in natural tasks, some memory errors might be more costly than others. This raises the intriguing possibility that the nature of memory error reflects the costs of committing different kinds of errors. Many existing theories assume that visual memories are noise-corrupted versions of afferent perceptual signals. However, this additive noise assumption oversimplifies the problem. Implicit in the behavioral phenomena of visual working memory is the concept of a loss function: a mathematical entity that describes the relative cost to the organism of making different types of memory errors. An optimally efficient memory system is one that minimizes the expected loss according to a particular loss function, while subject to a constraint on memory capacity. This paper describes a novel theoretical framework for characterizing visual working memory in terms of its implicit loss function. Using inverse decision theory, the empirical loss function is estimated from the results of a standard delayed recall visual memory experiment. These results are compared to the predicted behavior of a visual working memory system that is optimally efficient for a previously identified natural task, gaze correction following saccadic error. Finally, the approach is compared to alternative models of visual working memory, and shown to offer a superior account of the empirical data across a range of experimental datasets. © 2015 ARVO.

  7. Long-term symptomatic, functional, and work outcomes of carpal tunnel syndrome among construction workers.

    Science.gov (United States)

    Evanoff, Bradley; Gardner, Bethany T; Strickland, Jaime R; Buckner-Petty, Skye; Franzblau, Alfred; Dale, Ann Marie

    2016-05-01

    The long-term outcomes of carpal tunnel syndrome (CTS) including symptoms, functional status, work disability, and economic impact are unknown. We conducted a retrospective study of 234 active construction workers with medical claims for CTS and 249 workers without CTS claims; non-cases were matched on age, trade, and insurance eligibility. We conducted telephone interviews with cases and non-cases and collected administrative data on work hours. Compared to non-cases, CTS cases were more likely to report recurrent hand symptoms, decreased work productivity/quality, decreased performance of physical work demands, and greater functional limitations. Surgical cases showed larger improvements on multiple outcomes than non-surgical cases. Minimal differences in paid work hours were seen between cases and non-cases in the years preceding and following CTS claims. Persistent symptoms and functional impairments were present several years after CTS diagnosis. Long-term functional limitations shown by this and other studies indicate the need for improved prevention and treatment. © 2016 Wiley Periodicals, Inc.

  8. Variation in the thermionic work function of semiconductor powders exposed to electromagnetic radiation

    Science.gov (United States)

    Bourasseau, S.; Martin, J. R.; Juillet, F.; Teichner, S. J.

    1977-01-01

    The study of the variation of thermoelectronic work function potential of TiO2 in the presence of isobutane shows that this gas is not adsorbed on this solid, in either the presence or the absence of ultraviolet radiation. These results, as well as those obtained in a previous work, lead to the mechanism of the photo-oxidation of isobutane at room temperature, in which excited atomic oxygen is the active species.

  9. Mediating pathways and gender differences between shift work and subjective cognitive function.

    Science.gov (United States)

    Wong, Imelda S; Smith, Peter M; Ibrahim, Selahadin; Mustard, Cameron A; Gignac, Monique A M

    2016-11-01

    Increased injury risk among shift workers is often attributed to cognitive function deficits that come about as a result of sleep disruptions. However, little is known about the intermediate influences of other factors (eg, work stress, health) which may affect this relationship. In addition, gender differences in these the complex relationships have not been fully explored. The purpose of this study is to (1) identify the extent to which work and non-work factors mediate the relationship between shift work, sleep and subsequent subjective cognitive function; and (2) determine if the mediating pathways differ for men and women. Data from the 2010 National Population Health Survey was used to create a cross-sectional sample of 4255 employed Canadians. Using path modelling, we examined the direct and indirect relationships between shift work, sleep duration, sleep quality and subjective cognitive function. Multigroup analyses tested for significantly different pathways between men and women. Potential confounding effects of age and self-reported health and potential mediating effects of work stress were simultaneously examined. Work stress and sleep quality significantly mediated the effects of shift work on cognition. Age and health confounded the relationship between sleep quality and subjective cognition. No differences were found between men and women. Occupational health and safety programmes are needed to address stress and health factors, in addition to sleep hygiene, to effectively address cognitive function among shift workers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  10. Alternating Dynamics of Segregation and Integration in Human EEG Functional Networks During Working-memory Task.

    Science.gov (United States)

    Zippo, Antonio G; Della Rosa, Pasquale A; Castiglioni, Isabella; Biella, Gabriele E M

    2018-02-10

    Brain functional networks show high variability in short time windows but mechanisms governing these transient dynamics remain unknown. In this work, we studied the temporal evolution of functional brain networks involved in a working memory (WM) task while recording high-density electroencephalography (EEG) in human normal subjects. We found that functional brain networks showed an initial phase characterized by an increase of the functional segregation index followed by a second phase where the functional segregation faded after the prevailing the functional integration. Notably, wrong trials were associated with different or disrupted sequences of the segregation-integration profiles and measures of network centrality and modularity were able to identify crucial aspects of the oscillatory network dynamics. Additionally, computational investigations further supported the experimental results. The brain functional organization may respond to the information processing demand of a WM task following a 2-step atomic scheme wherein segregation and integration alternately dominate the functional configurations. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  11. Method for determining the work hardening function to describe plasticity of metals

    International Nuclear Information System (INIS)

    Wilkins, M.L.

    1978-01-01

    A method for obtaining a constitutive relation that relates the flow stress to the equivalent plastic strain is developed. The method uses simple tension test data to suggest a functional form. This form is then used as a constitutive model in a computer program that simulates the tension test. The calculated results are compared with the experimental results and the functional form is refined until agreement is obtained between calculations and experiments. The importance of knowing the relationship between the flow stress and the plastic strain is discussed. A work hardening function is calibrated for 6061 T6 aluminum

  12. Synthesis of carbon nanotubes bridging metal electrodes

    International Nuclear Information System (INIS)

    Kotlar, M.; Vojs, M.; Marton, M.; Vesel, M.; Redhammer, R.

    2012-01-01

    In our work we demonstrate growth of carbon nanotubes that can conductively bridge the metal electrodes. The role of different catalysts was examined. Interdigitated metal electrodes are made from copper and we are using bimetal Al/Ni as catalyst for growth of carbon nanotubes. We are using this catalyst composition for growth of the single-walled carbon nanotube network. (authors)

  13. Are intrinsic motivational factors of work associated with functional incapacity similarly regardless of the country?

    Science.gov (United States)

    Väänänen, A; Pahkin, K; Huuhtanen, P; Kivimäki, M; Vahtera, J; Theorell, T; Kalimo, R

    2005-10-01

    Many psychosocial models of wellbeing at work emphasise the role of intrinsic motivational factors such as job autonomy, job complexity, and innovativeness. However, little is known about whether the employees of multinational enterprises differ from country to country with regard to intrinsic motivational factors, and whether these factors are associated with wellbeing similarly in the different countries. The purpose of this study was to examine the level of intrinsic motivational factors and their impact on functional incapacity in different countries in a multinational corporation. In 2000, data were collected from a globally operating corporation with a questionnaire survey. The participants were 13 795 employees (response rate 59%; 56% under age 45; 80% men; 61% blue collar employees), who worked in similar industrial occupations in five countries (Canada, China, Finland, France, and Sweden). The Chinese employees reported higher autonomy and lower complexity at work than the employees from the other countries. After adjustment for age, sex, socioeconomic status, and physical work environment, job autonomy, and job complexity at work were associated with functional incapacity in most countries, whereas in China the impact was significantly stronger. In Finland and in China employees with low innovativeness at work were more prone to functional incapacity than corresponding employees in other countries. The level of intrinsic motivational factors varied between the Chinese employees and those in other countries. In line with theoretical notions, the relation between intrinsic motivational factors of work and functional incapacity followed a similar pattern in the different countries. However, these country specific results show that a culture specific approach to employee wellbeing should also be applied.

  14. Factors influencing work functioning after cancer diagnosis : a focus group study with cancer survivors and occupational health professionals

    NARCIS (Netherlands)

    Dorland, H. F.; Abma, F. I.; Roelen, C. A. M.; Smink, J. G.; Ranchor, A. V.; Bultmann, U.

    Cancer survivors (CSs) frequently return to work, but little is known about work functioning after return to work (RTW). We aimed to identify barriers and facilitators of work functioning among CSs. Three focus groups were conducted with CSs (n = 6, n = 8 and n = 8) and one focus group with

  15. Does Working Memory Impact Functional Outcomes in Individuals With ADHD: A Qualitative and Comprehensive Literature Review.

    Science.gov (United States)

    Fried, Ronna; Abrams, Jessica; Hall, Anna; Feinberg, Leah; Pope, Amanda; Biederman, Joseph

    2017-09-01

    Working Memory (WM) is a domain of executive functioning often impaired in individuals with ADHD. Although assumed to cause difficulties across functioning, the scope of impairments from WM deficits in ADHD has not been investigated. The aim of this study was to examine outcomes associated with WM deficits in ADHD. We conducted a search of the scientific literature on WM deficits, and Freedom From Distractibility (FFD), in ADHD using PubMed and PsycInfo databases. The final sample included 11 controlled studies of WM/FFD deficits in ADHD with operationalized assessment of outcomes in academic, social, and emotional areas. WM assessment was divided into auditory-verbal memory (AVM) and spatial-visual memory (SWM). Seven studies examined WM deficits in academic functioning, eight studies assessed WM deficits in social functioning, and three assessed WM deficits in psychopathology. The majority of the literature suggests that WM deficits affect primarily academic functioning.

  16. Rodent model for assessing the long term safety and performance of peripheral nerve recording electrodes

    Science.gov (United States)

    Vasudevan, Srikanth; Patel, Kunal; Welle, Cristin

    2017-02-01

    Objective. In the US alone, there are approximately 185 000 cases of limb amputation annually, which can reduce the quality of life for those individuals. Current prosthesis technology could be improved by access to signals from the nervous system for intuitive prosthesis control. After amputation, residual peripheral nerves continue to convey motor signals and electrical stimulation of these nerves can elicit sensory percepts. However, current technology for extracting information directly from peripheral nerves has limited chronic reliability, and novel approaches must be vetted to ensure safe long-term use. The present study aims to optimize methods to establish a test platform using rodent model to assess the long term safety and performance of electrode interfaces implanted in the peripheral nerves. Approach. Floating Microelectrode Arrays (FMA, Microprobes for Life Sciences) were implanted into the rodent sciatic nerve. Weekly in vivo recordings and impedance measurements were performed in animals to assess performance and physical integrity of electrodes. Motor (walking track analysis) and sensory (Von Frey) function tests were used to assess change in nerve function due to the implant. Following the terminal recording session, the nerve was explanted and the health of axons, myelin and surrounding tissues were assessed using immunohistochemistry (IHC). The explanted electrodes were visualized under high magnification using scanning electrode microscopy (SEM) to observe any physical damage. Main results. Recordings of axonal action potentials demonstrated notable session-to-session variability. Impedance of the electrodes increased upon implantation and displayed relative stability until electrode failure. Initial deficits in motor function recovered by 2 weeks, while sensory deficits persisted through 6 weeks of assessment. The primary cause of failure was identified as lead wire breakage in all of animals. IHC indicated myelinated and unmyelinated axons

  17. Influence of organic and functional dyspepsia on work productivity: the HEROES-DIP study.

    Science.gov (United States)

    Sander, Guilherme Becker; Mazzoleni, Luiz Edmundo; Francesconi, Carlos Ferrnando de Magalhães; Balbinotto, Giácomo; Mazzoleni, Felipe; Wortmann, Andre Castagna; Cardoso, Israel de Quadros; Klamt, Alexandre Luis; Milbradt, Tobias Cancian

    2011-01-01

    Dyspepsia is defined as persistent or recurrent abdominal pain or discomfort centered in the upper abdomen. Dyspepsia represents up to 8.3% of all primary care physician visits and causes huge economic costs to patients and to the economy as a whole. The aim of this study was to measure the influence of dyspepsia on work productivity of people within the Brazilian workforce. Adult patients were enrolled if they met the Roma III criteria for uninvestigated dyspepsia. All patients answered a demographic questionnaire. Productivity impairment was measured by the Work Productivity and Activity Impairment questionnaire. Subjects underwent upper gastrointestinal endoscopy and were classified as having functional or organic dyspepsia. The study protocol was approved by the Ethics Committee of Hospital de Clínicas de Porto Alegre, Brazil. Eight hundred fifty patients with dyspepsia were evaluated: 628 were women (73.9%); mean age was 46.4 ± 12.9 years; 387 (45.5%) were active workers. Among active workers, 32.2% mentioned that dyspepsia had caused absenteeism from work during the preceding week and 78% reported a reduction of the work productivity (presenteeism). The lost work productivity score was 35.7% among all employed patients. The affect on work productivity was similar between patients with functional or organic dyspepsia. Our study showed an important influence of dyspepsia on work productivity. We did not find any statistically significant difference on the influence on work between patients with organic dyspepsia and functional dyspepsia. The social impact of these findings is underscored by taking into account the prevalence (up to 40%) of this condition in Brazil. Copyright © 2011 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  18. Factors influencing work functioning after cancer diagnosis: a focus group study with cancer survivors and occupational health professionals.

    Science.gov (United States)

    Dorland, H F; Abma, F I; Roelen, C A M; Smink, J G; Ranchor, A V; Bültmann, U

    2016-01-01

    Cancer survivors (CSs) frequently return to work, but little is known about work functioning after return to work (RTW). We aimed to identify barriers and facilitators of work functioning among CSs. Three focus groups were conducted with CSs (n = 6, n = 8 and n = 8) and one focus group with occupational health professionals (n = 7). Concepts were identified by thematic analysis, using the Cancer and Work model as theoretical framework to structure the results. Long-lasting symptoms (e.g. fatigue), poor adaptation, high work ethics, negative attitude to work, ambiguous communication, lack of support and changes in the work environment were mentioned as barriers of work functioning. In contrast, staying at work during treatment, open dialogue, high social support, appropriate work accommodations and high work autonomy facilitated work functioning. Not only cancer-related symptoms affect work functioning of CSs after RTW but also psychosocial and work-related factors. The barriers and facilitators of work functioning should be further investigated in studies with a longitudinal design to examine work functioning over time.

  19. Functional specialization of the left ventral parietal cortex in working memory

    Directory of Open Access Journals (Sweden)

    Jennifer Lou Langel

    2014-06-01

    Full Text Available The function of the ventral parietal cortex (VPC is subject to much debate. Many studies suggest a lateralization of function in the VPC, with the left hemisphere facilitating verbal working memory and the right subserving stimulus-driven attention. However, many attentional tasks elicit activity in the VPC bilaterally. To elucidate the potential divides across the VPC in function, we assessed the pattern of activity in the VPC bilaterally across two tasks that require different demands, an oddball attentional task with low working memory demands and a working memory task. An anterior region of the VPC was bilaterally active during novel targets in the oddball task and during retrieval in WM, while more posterior regions of the VPC displayed dissociable functions in the left and right hemisphere, with the left being active during the encoding and retrieval of WM, but not during the oddball task and the right showing the reverse pattern. These results suggest that bilateral regions of the anterior VPC subserve non-mnemonic processes, such as stimulus-driven attention during WM retrieval and oddball detection. The left posterior VPC may be important for speech-related processing important for both working memory and perception, while the right hemisphere is more lateralized for attention.

  20. Intellectual Growth in Children as a Function of Domain Specific and Domain General Working Memory Subgroups

    Science.gov (United States)

    Swanson, H. Lee

    2011-01-01

    This study examined whether children's growth on measures of fluid (Raven Colored Progressive Matrices) and crystallized (reading and math achievement) intelligence was attributable to domain-specific or domain-general functions of working memory (WM). A sample of 290 elementary school children was tested on measures of intelligence across three…

  1. Channel length scaling and the impact of metal gate work function ...

    Indian Academy of Sciences (India)

    Further- more, quantum effects on the performance of DG-MOSFETs are addressed and discussed. We also study the influence of metal gate work function on the performance of nanoscale MOSFETs. We use a self-consistent Poisson–Schrödinger solver in two dimensions over the entire device. A good agreement with ...

  2. Large work function difference driven electron transfer from electrides to single-walled carbon nanotubes

    KAUST Repository

    Menamparambath, Mini Mol; Park, Jong Ho; Yoo, Ho Sung; Patole, Shashikant P.; Yoo, Ji Beom; Kim, Sung Wng; Baik, Seunghyun

    2014-01-01

    V. Here we investigated charge transfer between two different types of electrides, [Ca2N]+·e- and [Ca 24Al28O64]4+·4e-, and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca2N]+·e- with open 2-dimensional electron layers

  3. Preparing Transition-Age Students with High-Functioning Autism Spectrum Disorders for Meaningful Work

    Science.gov (United States)

    Lee, Gloria K.; Carter, Erik W.

    2012-01-01

    This article provides an overview of promising essential elements for fostering vocational success among students with high-functioning autism spectrum disorders (HFASDs) by drawing literature from the fields of school-to-work transition for post-secondary students and vocational rehabilitation for individuals with disabilities. We highlight seven…

  4. Functional Deficits in Phonological Working Memory in Children with Intellectual Disabilities

    Science.gov (United States)

    Schuchardt, Kirsten; Maehler, Claudia; Hasselhorn, Marcus

    2011-01-01

    Recent studies indicate that children with intellectual disabilities have functional limitations primarily in the phonological loop of working memory (Baddeley, 1986). These findings are indicative of a specific structural deficit. Building on this research, the present study examines whether it is possible to identify specific phonological…

  5. Large Work Function Modulation of Monolayer MoS2 by Ambient Gases.

    Science.gov (United States)

    Lee, Si Young; Kim, Un Jeong; Chung, JaeGwan; Nam, Honggi; Jeong, Hye Yun; Han, Gang Hee; Kim, Hyun; Oh, Hye Min; Lee, Hyangsook; Kim, Hyochul; Roh, Young-Geun; Kim, Jineun; Hwang, Sung Woo; Park, Yeonsang; Lee, Young Hee

    2016-06-28

    Although two-dimensional monolayer transition-metal dichalcogenides reveal numerous unique features that are inaccessible in bulk materials, their intrinsic properties are often obscured by environmental effects. Among them, work function, which is the energy required to extract an electron from a material to vacuum, is one critical parameter in electronic/optoelectronic devices. Here, we report a large work function modulation in MoS2 via ambient gases. The work function was measured by an in situ Kelvin probe technique and further confirmed by ultraviolet photoemission spectroscopy and theoretical calculations. A measured work function of 4.04 eV in vacuum was converted to 4.47 eV with O2 exposure, which is comparable with a large variation in graphene. The homojunction diode by partially passivating a transistor reveals an ideal junction with an ideality factor of almost one and perfect electrical reversibility. The estimated depletion width obtained from photocurrent mapping was ∼200 nm, which is much narrower than bulk semiconductors.

  6. Recovery to Preinterventional Functioning, Return-to-Work, and Life Satisfaction After Treatment of Unruptured Aneurysms

    NARCIS (Netherlands)

    Backes, Daan; Rinkel, Gabriel J. E.; van der Schaaf, Irene C.; Bijvank, Jenny A. Nij; Verweij, Bon H.; Visser-Meily, Johanna M. A.; Post, Marcel W.; Algra, Ale; Vergouwen, Mervyn D. I.

    Background and Purpose-The eventual goal of preventive treatment of unruptured intracranial aneurysms is to increase the number of life years with high life satisfaction. Insight in the time with reduced functioning, working capacity, and life satisfaction after aneurysm treatment is pivotal to

  7. Recovery to Preinterventional Functioning, Return-to-Work, and Life Satisfaction After Treatment of Unruptured Aneurysms

    NARCIS (Netherlands)

    Backes, D.; Rinkel, G.J.; Van der Schaaf, I.C.; Bijvank, J.A.; Verweij, B.H.; Visser-Meily, J.M.A.; Post, Marcel W.M.; Algra, A.; Vergouwen, M.D.

    Background and Purpose—The eventual goal of preventive treatment of unruptured intracranial aneurysms is to increase the number of life years with high life satisfaction. Insight in the time with reduced functioning, working capacity, and life satisfaction after aneurysm treatment is pivotal to

  8. Ab initio and work function and surface energy anisotropy of LaB6

    NARCIS (Netherlands)

    Uijttewaal, M. A.; de Wijs, G. A.; de Groot, R. A.

    2006-01-01

    Lanthanum hexaboride is one of the cathode materials most used in high-power electronics technology, but the many experimental results do not provide a consistent picture of the surface properties. Therefore, we report the first ab initio calculations of the work functions and surface energies of

  9. The role of neuropsychological functioning in cancer survivors' return to work one year after diagnosis

    NARCIS (Netherlands)

    Nieuwenhuijsen, Karen; de Boer, Angela; Spelten, Evelien; Sprangers, Mirjam A. G.; Verbeek, Jos H. A. M.

    2009-01-01

    Objective: The objective of this study was to investigate the relationship between neuropsychological functioning and the ability to work in cancer survivors. Methods: The study involved a consecutive cohort of 45 patients who had received a primary diagnosis of cancer, were gainfully employed at

  10. Mental disorders and personality traits as determinants of impaired work functioning

    NARCIS (Netherlands)

    Michon, H. W. C.; ten Have, M.; Kroon, H.; van Weeghel, J.; de Graaf, R.; Schene, A. H.

    2008-01-01

    Background. Both mental disorders and personality characteristics are associated with impaired work functioning, but these determinants have not yet been studied together. The aim of this paper is to examine the impairing effects that mental disorders and personality characteristics (i.e.

  11. Sleep disturbances and reduced work functioning in depressive or anxiety disorders

    NARCIS (Netherlands)

    van Mill, J.G.; Vogelzangs, N.; Hoogendijk, W.J.G.; Penninx, B.W.J.H.

    2013-01-01

    Objectives: We aimed to examine the associations between sleep disturbances and work functioning in an epidemiologic cohort study in subjects with or without depressive or anxiety disorders. Methods: There were 707 subjects included in our analyses with depressive or anxiety disorders and 728

  12. Sleep disturbances and reduced work functioning in depressive or anxiety disorders

    NARCIS (Netherlands)

    van Mill, Josine G.; Vogelzangs, Nicole; Hoogendijk, Witte J. G.; Penninx, Brenda W. J. H.

    Objectives: We aimed to examine the associations between sleep disturbances and work functioning in an epidemiologic cohort study in subjects with or without depressive or anxiety disorders. Methods: There were 707 subjects included in our analyses with depressive or anxiety disorders and 728

  13. Arithmetic difficulties in children with cerebral palsy are related to executive function and working memory.

    Science.gov (United States)

    Jenks, Kathleen M; de Moor, Jan; van Lieshout, Ernest C D M

    2009-07-01

    Although it is believed that children with cerebral palsy are at high risk for learning difficulties and arithmetic difficulties in particular, few studies have investigated this issue. Arithmetic ability was longitudinally assessed in children with cerebral palsy in special (n = 41) and mainstream education (n = 16) and controls in mainstream education (n = 16). Second grade executive function and working memory scores were used to predict third grade arithmetic accuracy and response time. Children with cerebral palsy in special education were less accurate and slower than their peers on all arithmetic tests, even after controlling for IQ, whereas children with cerebral palsy in mainstream education performed as well as controls. Although the performance gap became smaller over time, it did not disappear. Children with cerebral palsy in special education showed evidence of executive function and working memory deficits in shifting, updating, visuospatial sketchpad and phonological loop (for digits, not words) whereas children with cerebral palsy in mainstream education only had a deficit in visuospatial sketchpad. Hierarchical regression revealed that, after controlling for intelligence, components of executive function and working memory explained large proportions of unique variance in arithmetic accuracy and response time and these variables were sufficient to explain group differences in simple, but not complex, arithmetic. Children with cerebral palsy are at risk for specific executive function and working memory deficits that, when present, increase the risk for arithmetic difficulties in these children.

  14. HVDC Ground Electrodes and Tectonic Setting

    Science.gov (United States)

    Freire, P. F.; Pereira, S. Y.

    2017-12-01

    Ground electrodes in HVDC transmission are huge grounding systems for the DC part of the converter substation, about 1 km wide, sized to inject in the ground DC currents up to 3.5 kA. This work presents an analysis of how the tectonic setting at converter substation location is determinant for the search of the best electrode location (Site Selection) and on its design and performance. It will briefly present the author experience on HVDC electrode design, summarized as follows: Itaipu - Foz do Iguaçu electrodes (transmitter side) located in the middle of Paraná Sedimentary Basin, and Ibiúna electrodes (receiving side) on the border of the basin, 6 km from the geological strike, where the crystalline basement outcrops in São Paulo state; Madeira River - North electrodes (transmitting side) located on the Northwest border of South Amazon Craton, where the crystalline basement is below a shallow sediments layer, and South electrodes (receiving side) located within Paraná Sedimentary Basin; Chile - electrodes located on the Andean forearc, where the Nazca Plate plunges under the South American Plate; Kenya - Ethiopia - electrodes located in the African Rift; Belo Monte - North electrodes (transmitter side) located within the Amazonian Sedimentary Basin, about 35 km of its South border, and South electrodes (receiving side) within Paraná Sedimentary Basin (bipole 1) and on crystalline metamorphic terrain "Brasília Belt" (bipole 2). This diversity of geological conditions results on ground electrodes of different topologies and dimensions, with quite different electrical and thermal performances. A brief study of the geology of the converter stations regions, the so-called Desktop Study, allows for the preview of several important parameters for the site selection and design of the electrodes, such as localization, type, size and estimate of the interference area, which are important predictors of the investment to be made and indications of the design to be

  15. Labor supply functions of working male and female pharmacists: In search of the backward bend.

    Science.gov (United States)

    Carvajal, Manuel J; Deziel, Lisa; Armayor, Graciela M

    2012-01-01

    Previous research has shown that U.S. pharmacists experience negative elasticities along a backward-bending labor supply function. The presence of a backward bend in the labor supply curve may cause a decrease in the amount of work at a time of labor shortage. Therefore, the determinants of pharmacists' labor supply functions should be explored to assess the impact of this backward bend. To determine whether female and male pharmacist work inputs are influenced by the same factors and estimate where the backward bend occurs, if at all, in their labor supply functions. Data were collected using a survey questionnaire mailed to registered pharmacists in South Florida. Labor supply functions were formulated and tested separately for 558 men and 498 women. The wage rate, other household income, human capital stock, job-related preferences, and opinion variables were hypothesized to explain labor supply differentials. Human capital stock variables included professional experience, holding a specialty board certification, and number of children; job-related preference variables included urban-rural location of work site and main role as a practitioner; and opinion variables included stress, autonomy, fairness in the workplace, flexibility, and job security. Men and women responded differently to identical stimuli, and their supply functions were influenced in different ways by the explanatory variables. Both genders exhibited positive labor supply elasticities greater than those reported in other studies. Both genders' backward bend in their labor supply functions occurred several standard deviations to the right of the mean. The backward bend in the labor supply functions of male and female pharmacists is not likely to affect in the near future the labor market's ability to regulate shortages of practitioners via increases in the wage rate. A more thorough understanding of pharmacists' labor supply functions must address gender issues and differences in response to

  16. Strain Effect on Electronic Structure and Work Function in α-Fe2O3 Films

    Directory of Open Access Journals (Sweden)

    Li Chen

    2017-03-01

    Full Text Available We investigate the electronic structure and work function modulation of α-Fe2O3 films by strain based on the density functional method. We find that the band gap of clean α-Fe2O3 films is a function of the strain and is influenced significantly by the element termination on the surface. The px and py orbitals keep close to Fermi level and account for a pronounced narrowing band gap under compressive strain, while unoccupied dz2 orbitals from conduction band minimum draw nearer to Fermi level and are responsible for the pronounced narrowing band gap under tensile strain. The spin polarized surface state, arising from localized dangling-bond states, is insensitive to strain, while the bulk band, especially for pz orbital, arising from extended Bloch states, is very sensitive to strain, which plays an important role for work function decreasing (increasing under compressive (tensile strain in Fe termination films. In particular, the work function in O terminated films is insensitive to strain because pz orbitals are less sensitive to strain than that of Fe termination films. Our findings confirm that the strain is an effective means to manipulate electronic structures and corrosion potential.

  17. Understanding of the correlation between work function and surface morphology of metals and alloys

    International Nuclear Information System (INIS)

    Xue, Mingshan; Wang, Wenfeng; Wang, Fajun; Ou, Junfei; Li, Changquan; Li, Wen

    2013-01-01

    Highlights: •The inherent correlation between the work function and surface morphology was focused on. •The change of the work function of metals and alloys as a function of surface roughness was investigated by scanning Kelvin probe. •The lightning rod effect was used to describe the electron transport at a rough surface. -- Abstract: The relationships between material behaviors and its structures are extremely complicated, and the understanding of these relationships is of much significance for revealing the physical, chemical and mechanical properties of various materials. In this study, the change of the work function (WF) of metals and alloys as a function of surface roughness was investigated by scanning Kelvin probe, with the aim of understanding the inherent correlation between the WF and surface morphology using a simple and intuitive way. It was demonstrated that at the rough surface of Cu and Ag, the sharp micro/nanostructures induced a lower WF, just as the lightning rod effect providing a direct and fast path for electron transport. While for Al and Mg alloys, the rough surface resulted in an increase of the WF owing to the effect of surface oxide layers, just as the anti-lightning rod effect providing a protected layer to confine the electron transport

  18. Extremely environment-hard and low work function transfer-mold field emitter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Masayuki, E-mail: m-nakamoto@rie.shizuoka.ac.jp [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8011 (Japan); Moon, Jonghyun [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8011 (Japan)

    2013-06-15

    Extremely environment-hard and low work function field-emitter arrays (FEAs) were fabricated by a transfer-mold emitter fabrication method to produce highly reliable vacuum nanoelectronic devices able to operate stably at low voltage in highly oxidizing atmospheres. Amorphous carbon (a-C) having a work function of 3.6 eV and sp{sup 3} fraction of 85.6% prepared by plasma-enhanced chemical vapor deposition was used as the emitter material. The field-emission characteristics of the obtained transfer-mold FEAs strongly depended on their work function and morphology. The environment-hard characteristics of the transfer-mold a-C FEAs were compared with those of the transfer-mold titanium nitride FEAs and nickel FEAs. X-ray photoelectron spectroscopy was used to confirm the stable chemical states of the FEAs after oxygen radical treatment. The small amount of material oxidized (6.3%) at the surface of the a-C FEAs compared with 11.8% for the TiN-FEAs and 39.0% for Ni FEAs after oxygen radical treatment explained their almost constant work function in oxidizing atmospheres. The emission fluctuation rates of transfer-mold a-C FEAs without resistive layers under in situ radical treatment were as low as ±5.0%, compared with 5–100% for conventional FEAs with resistive layers not under highly oxidizing atmospheres. Therefore, the present environment-hard and low work function transfer-mold a-C FEAs are expected to be useful for reliable vacuum nanoelectronic devices.

  19. High performance cermet electrodes

    Science.gov (United States)

    Isenberg, Arnold O.; Zymboly, Gregory E.

    1986-01-01

    Disclosed is a method of increasing the operating cell voltage of a solid oxide electrochemical cell having metal electrode particles in contact with an oxygen-transporting ceramic electrolyte. The metal electrode is heated with the cell, and oxygen is passed through the oxygen-transporting ceramic electrolyte to the surface of the metal electrode particles so that the metal electrode particles are oxidized to form a metal oxide layer between the metal electrode particles and the electrolyte. The metal oxide layer is then reduced to form porous metal between the metal electrode particles and the ceramic electrolyte.

  20. Organophosphonate biofunctionalization of diamond electrodes.

    Science.gov (United States)

    Caterino, R; Csiki, R; Wiesinger, M; Sachsenhauser, M; Stutzmann, M; Garrido, J A; Cattani-Scholz, A; Speranza, Giorgio; Janssens, S D; Haenen, K

    2014-08-27

    The modification of the diamond surface with organic molecules is a crucial aspect to be considered for any bioapplication of this material. There is great interest in broadening the range of linker molecules that can be covalently bound to the diamond surface. In the case of protein immobilization, the hydropathicity of the surface has a major influence on the protein conformation and, thus, on the functionality of proteins immobilized at surfaces. For electrochemical applications, particular attention has to be devoted to avoid that the charge transfer between the electrode and the redox center embedded in the protein is hindered by a thick insulating linker layer. This paper reports on the grafting of 6-phosphonohexanoic acid on OH-terminated diamond surfaces, serving as linkers to tether electroactive proteins onto diamond surfaces. X-ray photoelectron spectroscopy (XPS) confirms the formation of a stable layer on the surface. The charge transfer between electroactive molecules and the substrate is studied by electrochemical characterization of the redox activity of aminomethylferrocene and cytochrome c covalently bound to the substrate through this linker. Our work demonstrates that OH-terminated diamond functionalized with 6-phosphonohexanoic acid is a suitable platform to interface redox-proteins, which are fundamental building blocks for many bioelectronics applications.

  1. Work performance evaluation and QoL of adults with High Functioning Autism Spectrum Disorders (HFASD).

    Science.gov (United States)

    Katz, Noomi; Dejak, Ifat; Gal, Eynat

    2015-01-01

    Studies suggest that adults with High Functioning Autism Spectrum Disorders (HFASD) are reliant on others for support in functioning in everyday life and employment. This study followed a work placement program for people with HFASD over a nine months period. It aimed to measure the trajectory of their work performance and Quality of life on jobs in the open market. Twenty-six participants with HFASD ages 18-40 underwent extensive evaluation and based on it were placed in various jobs on the open market. Participants were followed for nine months at their work place at four different time points. QoL was self-assessed in addition to work performance (WPE) which was assessed both by first-hand and team member's accounts. Team members are health professional who accompany and support the participants in the transition to their jobs. All 26 participants were able to maintain their jobs during the nine months of follow-up. WPE was perceived as high to start with, and its scores slightly improved by both people with HFASD and team members. Self-report suggests a significant change in the quality of life of the participants, specifically in their evaluations of self-competency. This study enhances the importance of providing people with HFASD with work placing programs and following up during actual work performance.

  2. Effects of work stress and home stress on autonomic nervous function in Japanese male workers.

    Science.gov (United States)

    Maeda, Eri; Iwata, Toyoto; Murata, Katsuyuki

    2015-01-01

    Autonomic imbalance is one of the important pathways through which psychological stress contributes to cardiovascular diseases/sudden death. Although previous studies have focused mainly on stress at work (work stress), the association between autonomic function and stress at home (home stress) is still poorly understood. The purpose was to clarify the effect of work/home stress on autonomic function in 1,809 Japanese male workers. We measured corrected QT (QTc) interval and QT index on the electrocardiogram along with blood pressure and heart rate. Participants provided self-reported information about the presence/absence of work/home stress and the possible confounders affecting QT indicators. Home stress was related positively to QT index (p=0.040) after adjusting for the possible confounders, though work stress did not show a significant relation to QTc interval or QT index. The odds ratio of home stress to elevated QT index (≥105) was 2.677 (95% CI, 1.050 to 6.822). Work/home stress showed no significant relation to blood pressure or heart rate. These findings suggest that autonomic imbalance, readily assessed by QT indicators, can be induced by home stress in Japanese workers. Additional research is needed to identify different types of home stress that are strongly associated with autonomic imbalance.

  3. Determination of picomolar silver concentrations by differential pulse anodic stripping voltammetry at a carbon paste electrode modified with phenylthiourea-functionalized high ordered nanoporous silica gel

    International Nuclear Information System (INIS)

    Javanbakht, Mehran; Divsar, Faten; Badiei, Alireza; Fatollahi, Fatemeh; Khaniani, Yeganeh; Ganjali, Mohammad Reza; Norouzi, Parviz; Chaloosi, Marzieh; Ziarani, Ghodsi Mohammadi

    2009-01-01

    This study introduces the design of an anodic stripping voltammetric (ASV) method for the silver ion determination at a carbon paste electrode (CPE), chemically modified with phenylthiourea-nanoporous silica gel (Tu-SBA-15-CPE). The electroanalytical pro includes two steps: preconcentration of metal ions at an electrode surface, followed by quantification of the accumulated species by differential pulse anodic stripping voltammetric methods. Factors affecting the performance of the anodic stripping were investigated, including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The most sensitive and reliable electrode contained 10% Tu-SBA-15 and 90% carbon paste. The accumulation potential and time were set at, -200 mV and 300 s, respectively, and the scan rate at 50 mV s -1 in the scan range of -200 to 700 mV. The resulting electrode demonstrated a linear response over range of silver ion concentration of 8.0-80 pmol/L with detection limit (S/N = 3) of 5 pmol/L. The prepared electrodes were used for the silver determination in sea and tap water samples and very good recovery results were obtained. The accuracy was assessed through recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry.

  4. Determination of picomolar silver concentrations by differential pulse anodic stripping voltammetry at a carbon paste electrode modified with phenylthiourea-functionalized high ordered nanoporous silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Javanbakht, Mehran [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Nano Science and Technology Research Center, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)], E-mail: mehranjavanbakht@gmail.com; Divsar, Faten [Department of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of); Badiei, Alireza [School of Chemistry, University College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Fatollahi, Fatemeh [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Khaniani, Yeganeh [School of Chemistry, University College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza; Norouzi, Parviz [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Chaloosi, Marzieh [Department of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of); Ziarani, Ghodsi Mohammadi [Department of Chemistry, University of Alzahra, Tehran (Iran, Islamic Republic of)

    2009-09-30

    This study introduces the design of an anodic stripping voltammetric (ASV) method for the silver ion determination at a carbon paste electrode (CPE), chemically modified with phenylthiourea-nanoporous silica gel (Tu-SBA-15-CPE). The electroanalytical pro includes two steps: preconcentration of metal ions at an electrode surface, followed by quantification of the accumulated species by differential pulse anodic stripping voltammetric methods. Factors affecting the performance of the anodic stripping were investigated, including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The most sensitive and reliable electrode contained 10% Tu-SBA-15 and 90% carbon paste. The accumulation potential and time were set at, -200 mV and 300 s, respectively, and the scan rate at 50 mV s{sup -1} in the scan range of -200 to 700 mV. The resulting electrode demonstrated a linear response over range of silver ion concentration of 8.0-80 pmol/L with detection limit (S/N = 3) of 5 pmol/L. The prepared electrodes were used for the silver determination in sea and tap water samples and very good recovery results were obtained. The accuracy was assessed through recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry.

  5. Risk and Work Configuration Management as a Function of Integrated Safety Management

    International Nuclear Information System (INIS)

    Lana Buehrer; Michele Kelly; Fran Lemieux; Fred Williams

    2007-01-01

    National Security Technologies, LLC (NSTec), has established a work management program and corresponding electronic Facilities and Operations Management Information System (e-FOM) to implement Integrated Safety Management (ISM). The management of work scopes, the identification of hazards, and the establishment of implementing controls are reviewed and approved through electronic signatures. Through the execution of the program and the implementation of the electronic system, NSTec staff work within controls and utilize feedback and improvement process. The Integrated Work Control Manual further implements the five functions of ISM at the Activity level. By adding the Risk and Work Configuration Management program, NSTec establishes risk acceptance (business and physical) for liabilities within the performance direction and work management processes. Requirements, roles, and responsibilities are specifically identified in the program while e-FOM provides the interface and establishes the flowdown from the Safety Chain to work and facilities management processes to company work-related directives, and finally to Subject Matter Expert concurrence. The Program establishes, within the defined management structure, management levels for risk identification, risk mitigation (controls), and risk acceptance (business and physical) within the Safety Chain of Responsibility. The Program also implements Integrated Safeguards and Security Management within the NSTec Safety Chain of Responsibility. Once all information has been entered into e-FOM, approved, and captured as data, the information becomes searchable and sortable by hazard, location, organization, mitigating controls, etc

  6. Spatial and verbal working memory: A functional magnetic resonance imaging study

    Directory of Open Access Journals (Sweden)

    Blaž Koritnik

    2004-08-01

    Full Text Available According to numerous studies, working memory is not a unitary system. Baddeley's model of working memory includes besides central executive also two separate systems for verbal and visuo-spatial information processing. A modality- and process-specific specialization presumably exists in working memory system of the frontal lobes. In our preliminary study, we have used functional magnetic resonance imaging to study the pattern of cortical activation during spatial and verbal n-back task in six healthy subjects. A bilateral fronto-parietal cortical network was activated in both tasks. There was larger activation of right parietal and bilateral occipital areas in spatial than in vebal task. Activation of left sensorimotor area was larger in verbal compared to spatial task. No task-specific differences were found in the prefrontal cortex. Our results support the assumption that modality-specific processes exist within the working-memory system.

  7. Functional and environmental factors affecting work status in individuals with longstanding poliomyelitis.

    Science.gov (United States)

    Zeilig, Gabi; Weingarden, Harold; Shemesh, Yeheskel; Herman, Amir; Heim, Michael; Zeweker, Manual; Dudkiewicz, Israel

    2012-01-01

    Remunerative employment is a major concern of individuals with chronic disabilities, among them, those with longstanding poliomyelitis (LSP). Although LSP is not rare there are almost no data related to work participation. The aims of the current study were to determine the effects of a number of social and functional variables as barriers or facilitators to work participation in persons with LSP. Charts of 123 LSP patients of working age that were seen in the post-polio outpatient clinic, between the years 2000 and 2005 were reviewed for the study. Data on age, gender, family status, level of function in activities of daily living, basic, and extended (B-ADL and E-ADL), and mobility were then analyzed for correlation to the vocational status. Seventy-two people (58.5%) were employed at the time of the survey. Gender and marital status were not found to significantly differ as regard to employment. Using assistive devices for mobility or being dependent for basic ADL were associated with lower levels of employment. Driving was positively associated with the employment status of the LSP individuals. Persons with LSP encounter important barriers to work participation, particularly on the International Classification of Functioning, Disability, and Health (ICF) components of activity and environment.

  8. [Functional childhood gastrointestinal disorders. III. Constipation and solitary encopresis; diagnostic work-up and therapy].

    Science.gov (United States)

    van Ginkel, R; Büller, H A; Heymans, H S; Taminiau, J A; Boeckxstaens, G E; Benninga, M A

    2003-06-28

    A detailed medical history in combination with a thorough physical examination, including rectal examination, form the cornerstone in the diagnostic work-up for children with functional defecation disorders. Additional investigations are often not informative and have only minor diagnostic or therapeutic implications. Medical therapy in children with functional constipation and solitary encopresis is primarily based on clinical experience. In both patient groups, the role of education, the use of diary cards and toilet training is important. In some patients behaviour interventions are important. Oral laxatives are the basis of treatment of children with functional constipation, whereas they are contra-indicated in children with solitary encopresis. In both groups, biofeedback training appears to be of little additional benefit. Long-term follow-up of children with functional defecation disorders shows that complaints continue far beyond puberty in many children.

  9. Effectiveness of computerized cognitive rehabilitation training on symptomatological, neuropsychological and work function in patients with schizophrenia.

    Science.gov (United States)

    Lee, Woo Kyeong

    2013-06-01

    There has been plenty of interest in cognitive rehabilitation for schizophrenia here in Korea since the year 2000. But the efficacy studies of cognitive remediation intervention are still deficient. The primary purpose of this study was to develop a computer-assisted cognitive remediation program and conduct a clinical trial in a group of schizophrenic patients. Sixty patients with schizophrenia were randomly assigned to a computerized cognitive rehabilitation (Cog-trainer) group plus usual rehabilitation (UR) or to a usual rehabilitation (UR) group only. Clinical, neuropsychological and functional outcome variables were assessed at baseline and after intervention. The Cog-trainer group received 20 sessions of computerized cognitive remediation training over 3 months. This training program consists of 10 units, with each unit being divided into three stages: (i) practice; (ii) application; and (iii) advanced. Compared to the UR group, the Cog-trainer exhibited a significant improvement in attention, concentration and working memory. The Cog-trainer group also showed improvement in the work quality subscale of the work behavior inventory. However, there were no significant benefits of computerized cognitive remediation where symptoms were concerned. These results indicate that computerized cognitive rehabilitation training can contribute to an improvement in the cognitive function of people with schizophrenia. The changes in cognitive outcomes can also contribute to improvement in job functioning. Further study of generalization to other functional outcome measures will be necessary. Long-term follow-up studies are needed to confirm the maintenance of such improvements. Copyright © 2013 Wiley Publishing Asia Pty Ltd.

  10. Work Function of Oxide Ultrathin Films on the Ag(100) Surface.

    Science.gov (United States)

    Sementa, Luca; Barcaro, Giovanni; Negreiros, Fabio R; Thomas, Iorwerth O; Netzer, Falko P; Ferrari, Anna Maria; Fortunelli, Alessandro

    2012-02-14

    Theoretical calculations of the work function of monolayer (ML) and bilayer (BL) oxide films on the Ag(100) surface are reported and analyzed as a function of the nature of the oxide for first-row transition metals. The contributions due to charge compression, charge transfer and rumpling are singled out. It is found that the presence of empty d-orbitals in the oxide metal can entail a charge flow from the Ag(100) surface to the oxide film which counteracts the decrease in the work function due to charge compression. This flow can also depend on the thickness of the film and be reduced in passing from ML to BL systems. A regular trend is observed along first-row transition metals, exhibiting a maximum for CuO, in which the charge flow to the oxide is so strong as to reverse the direction of rumpling. A simple protocol to estimate separately the contribution due to charge compression is discussed, and the difference between the work function of the bare metal surface and a Pauling-like electronegativity of the free oxide slabs is used as a descriptor quantity to predict the direction of charge transfer.

  11. Carbon Paste Electrodes Made from Different Carbonaceous Materials: Application in the Study of Antioxidants

    Science.gov (United States)

    Apetrei, Constantin; Apetrei, Irina Mirela; De Saja, Jose Antonio; Rodriguez-Mendez, Maria Luz

    2011-01-01

    This work describes the sensing properties of carbon paste electrodes (CPEs) prepared from three different types of carbonaceous materials: graphite, carbon microspheres and carbon nanotubes. The electrochemical responses towards antioxidants including vanillic acid, catechol, gallic acid, l-ascorbic acid and l-glutathione have been analyzed and compared. It has been demonstrated that the electrodes based on carbon microspheres show the best performances in terms of kinetics and stability, whereas G-CPEs presented the smallest detection limit for all the antioxidants analyzed. An array of electrodes has been constructed using the three types of electrodes. As demonstrated by means of Principal Component Analysis, the system is able to discriminate among antioxidants as a function of their chemical structure and reactivity. PMID:22319354

  12. Post-retirement voluntary work and psychological functioning among older Chinese in Hong Kong.

    Science.gov (United States)

    Wu, Anise M S; Tang, Catherine S K; Yan, Elsie C W

    2005-03-01

    This study examined demographic and psychosocial differences between older Chinese volunteers and non-volunteers. The influences of work-related factors on older Chinese volunteers' post-retirement psychological functioning and life satisfaction were also explored. A total of 501 older Chinese in Hong Kong were individually interviewed. About 65% of them were involved in community voluntary work since their retirement, with an average of four hours per week. Compared to those without voluntary work experiences, older Chinese volunteers had higher educational attainment and reported better physical health, higher self-efficacy, greater life satisfaction, and less psychological distress. Results from hierarchical regression analyses showed that salient correlates of a low level of psychological distress in older Chinese volunteers were high educational attainment, high self-efficacy, perceived good physical health, and high levels of perceived rewards and satisfaction from voluntary work. Self-efficacy and perceived rewards from voluntary work were also salient correlates of life satisfaction for older Chinese volunteers. As hypothesized, work-related factors of perceived rewards and work satisfaction remained significant correlates of older volunteers' psychological well-being, even after controlling for demographic and individual psychosocial factors. Limitations and implications of the study were also discussed.

  13. Fluoxetine improves functional work capacity in women with premenstrual dysphoric disorder.

    Science.gov (United States)

    Steiner, M; Brown, E; Trzepacz, P; Dillon, J; Berger, C; Carter, D; Reid, R; Stewart, D

    2003-02-01

    Interference with social and occupational functioning is a key criterion for premenstrual dysphoric disorder (PMDD) and distinguishes it from the less severe premenstrual syndrome (PMS). We conducted a post hoc analysis of the results of a previously reported study evaluating the efficacy of fluoxetine in the management of PMDD, to determine the extent to which women with PMDD perceived impairment in their functional work capacity during the luteal phase of their menstrual cycle. The effects of two doses of fluoxetine vs placebo in alleviating PMDD symptoms and restoring normal work capacity during this period were assessed. We measured baseline follicular vs luteal phase presence of 8 patient-rated functional work capacity-related symptoms on the Premenstrual Tension Scale-Self Rated in 320 women who met diagnostic criteria for late luteal phase dysphoric disorder, now known as PMDD. Women were then randomized to double-blind treatment with either fluoxetine 20 mg/d, fluoxetine 60 mg/d, or placebo daily for 6 menstrual cycles. All 8 work capacity-related symptoms were more likely to be present in the baseline luteal phase than in the baseline follicular phase. A statistically significant improvement from baseline to the average treatment score for the work capacity subscale was detected for both fluoxetine groups compared to the placebo group. This beneficial response to fluoxetine was evident by the first cycle of treatment. Our results demonstrate that fluoxetine at a relatively low dose of 20 mg/d quickly reduced symptoms that negatively affect work capacity and was well tolerated.

  14. Functional capacity associated with work ability in older university staff employed by the state

    Directory of Open Access Journals (Sweden)

    Juleimar Soares Coelho de Amorim

    Full Text Available Abstract Introduction: The increase in numbers of older adults in the workplace and in the number of years they spend in work prior to retiring has challenged health professionals to provide enable health conditions such that they may undertake occupational activity. Objective: To analyze the variables for functional ability, associated with work ability, in older adults who were government employees at a university. Methods: A cross-sectional design, with older workers aged 60 years old or over, located in different university centers and departments. A structured sociodemographic questionnaire was used to characterize the sample, and the Work Ability Index was used as an outcome variable for the associations, using the Timed Up and Go test, the handgrip strength test, the walking speed test and the chair sit to stand test. The Chi-squared test and Pearson correlation coefficient were used in the statistical analysis. The association of the factors of functional capacity was based on the odds ratio and 95% confidence interval, calculated using the Logistic Regression Model, as part of the SPSS statistical package for Windows. Results: A total of 258 staff participated in the investigation, with men (57.7% and a lower age range (60 to 62 years old predominating. Women differed in relation to falls after the age of 60 (p = 0.007 and in the last 12 months (p = 0.017. The mean Work Ability Index was 39.70 ± 5.64 points and a statistical association was ascertained between performance in the chair sit to stand test (OR = 2.26; p = 0.043. Muscle strength (r = 0.72; p < 0.000 and the chair sit to stand test (r = 0.73; p < 0.000 showed excellent correlation with work ability. Conclusion: The variables for functional capacity were associated with work ability.

  15. CFD analysis of a symmetrical planar SOFC with heterogeneous electrode properties

    International Nuclear Information System (INIS)

    Shi Junxiang; Xue Xingjian

    2010-01-01

    A comprehensive 2-D CFD model is developed to investigate bi-electrode supported cell (BSC) performance. The model takes into account the coupled complex transport phenomena of mass/heat transfer, charge (electron/ion) transport, and electrochemical reactions. The uniqueness of this modeling work is that heterogeneous electrode properties are taken into account, which includes not only linear functionally graded porosity distribution but also various nonlinear distributions in a general sense according to porous electrode features in BSC design. Extensive numerical analysis is performed to elucidate various heterogeneous porous electrode property effects on cell performance. Results indicate that cell performance is strongly dependent on porous microstructure distributions of electrodes. Among the various porosity distributions, inverse parabolic porosity distribution shows promising effects on cell performance. For a given porosity distribution of electrodes, cell performance is also dependent on operating conditions, typically fuel/gas pressure losses across the electrodes. The mathematical model developed in this paper can be utilized for high performance BSC SOFC design and optimization.

  16. High-performance NiO/Ag/NiO transparent electrodes for flexible organic photovoltaic cells.

    Science.gov (United States)

    Xue, Zhichao; Liu, Xingyuan; Zhang, Nan; Chen, Hong; Zheng, Xuanming; Wang, Haiyu; Guo, Xiaoyang

    2014-09-24

    Transparent electrodes with a dielectric-metal-dielectric (DMD) structure can be implemented in a simple manufacturing process and have good optical and electrical properties. In this study, nickel oxide (NiO) is introduced into the DMD structure as a more appropriate dielectric material that has a high conduction band for electron blocking and a low valence band for efficient hole transport. The indium-free NiO/Ag/NiO (NAN) transparent electrode exhibits an adjustable high transmittance of ∼82% combined with a low sheet resistance of ∼7.6 Ω·s·q(-1) and a work function of 5.3 eV after UVO treatment. The NAN electrode shows excellent surface morphology and good thermal, humidity, and environmental stabilities. Only a small change in sheet resistance can be found after NAN electrode is preserved in air for 1 year. The power conversion efficiencies of organic photovoltaic cells with NAN electrodes deposited on glass and polyethylene terephthalate (PET) substrates are 6.07 and 5.55%, respectively, which are competitive with those of indium tin oxide (ITO)-based devices. Good photoelectric properties, the low-cost material, and the room-temperature deposition process imply that NAN electrode is a striking candidate for low-cost and flexible transparent electrode for efficient flexible optoelectronic devices.

  17. Functional MRI study of verbal working memory in children with attention deficit hyperactivity disorder

    International Nuclear Information System (INIS)

    Lu Youran; Geng Daoying; Feng Xiaoyuan; Du Yasong; Zhao Zhimin

    2006-01-01

    Objective: To study the verbal working memory of children with attention deficit hyperactivity disorder (ADHD) as well as to explore the characteristics of functional areas of verbal working memory with blood oxygenation level dependent functional magnetic resonance imaging (fMRI). Method: Eighteen children were selected in the study. There were 9 ADHD children with inattention subtype and 9 healthy subjects. All patients and healthy subjects completed the cognitive examination and the block- designed N-block verbal working memory task using a GE 3.0 T MR. Data were analyzed by AFNI software. Result: The neural activations of ADHD's children are lower than that of control under verbal working memory. Especially in the areas of bilateral middle frontal gyri and inferior frontal gyri, bilateral superior parietal lobules and inferior parietal lobules, right basal ganglia in the 1-BACK task. And bilateral middle frontal gyri and inferior frontal gyri, bilateral superior parietal lobules, left cortex inferior parietallobule, right basal ganglia, anterior cingulatecortex in the 2-BACK task. Conclusion: The hypofunctional areas of verbal working memory (including bilateral dorsolateral prefrontal cortex and parietal cortex) can be seen in the ADHD children especially who also has lower activation of anterior cingulate cortex under 2-BACK task. (authors)

  18. Reaction Times to Consecutive Automation Failures: A Function of Working Memory and Sustained Attention.

    Science.gov (United States)

    Jipp, Meike

    2016-12-01

    This study explored whether working memory and sustained attention influence cognitive lock-up, which is a delay in the response to consecutive automation failures. Previous research has demonstrated that the information that automation provides about failures and the time pressure that is associated with a task influence cognitive lock-up. Previous research has also demonstrated considerable variability in cognitive lock-up between participants. This is why individual differences might influence cognitive lock-up. The present study tested whether working memory-including flexibility in executive functioning-and sustained attention might be crucial in this regard. Eighty-five participants were asked to monitor automated aircraft functions. The experimental manipulation consisted of whether or not an initial automation failure was followed by a consecutive failure. Reaction times to the failures were recorded. Participants' working-memory and sustained-attention abilities were assessed with standardized tests. As expected, participants' reactions to consecutive failures were slower than their reactions to initial failures. In addition, working-memory and sustained-attention abilities enhanced the speed with which participants reacted to failures, more so with regard to consecutive than to initial failures. The findings highlight that operators with better working memory and sustained attention have small advantages when initial failures occur, but their advantages increase across consecutive failures. The results stress the need to consider personnel selection strategies to mitigate cognitive lock-up in general and training procedures to enhance the performance of low ability operators. © 2016, Human Factors and Ergonomics Society.

  19. Development of utility generic functional requirements for electronic work packages and computer-based procedures

    Energy Technology Data Exchange (ETDEWEB)

    Oxstrand, Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-01

    The Nuclear Electronic Work Packages - Enterprise Requirements (NEWPER) initiative is a step toward a vision of implementing an eWP framework that includes many types of eWPs. This will enable immediate paper-related cost savings in work management and provide a path to future labor efficiency gains through enhanced integration and process improvement in support of the Nuclear Promise (Nuclear Energy Institute 2016). The NEWPER initiative was organized by the Nuclear Information Technology Strategic Leadership (NITSL) group, which is an organization that brings together leaders from the nuclear utility industry and regulatory agencies to address issues involved with information technology used in nuclear-power utilities. NITSL strives to maintain awareness of industry information technology-related initiatives and events and communicates those events to its membership. NITSL and LWRS Program researchers have been coordinating activities, including joint organization of NEWPER-related meetings and report development. The main goal of the NEWPER initiative was to develop a set of utility generic functional requirements for eWP systems. This set of requirements will support each utility in their process of identifying plant-specific functional and non-functional requirements. The NEWPER initiative has 140 members where the largest group of members consists of 19 commercial U.S. nuclear utilities and eleven of the most prominent vendors of eWP solutions. Through the NEWPER initiative two sets of functional requirements were developed; functional requirements for electronic work packages and functional requirements for computer-based procedures. This paper will describe the development process as well as a summary of the requirements.

  20. Effects of electrode material and configuration on the characteristics of planar resistive switching devices

    KAUST Repository

    Peng, H.Y.

    2013-11-13

    We report that electrode engineering, particularly tailoring the metal work function, measurement configuration and geometric shape, has significant effects on the bipolar resistive switching (RS) in lateral memory devices based on self-doped SrTiO3 (STO) single crystals. Metals with different work functions (Ti and Pt) and their combinations are used to control the junction transport (either ohmic or Schottky-like). We find that the electric bias is effective in manipulating the concentration of oxygen vacancies at the metal/STO interface, influencing the RS characteristics. Furthermore, we show that the geometric shapes of electrodes (e.g., rectangular, circular, or triangular) affect the electric field distribution at the metal/oxide interface, thus plays an important role in RS. These systematic results suggest that electrode engineering should be deemed as a powerful approach toward controlling and improving the characteristics of RS memories. 2013 Author(s).

  1. The CRINE initiative -- Producing the engineering tools (functional specifications and common working practices)

    International Nuclear Information System (INIS)

    Tuft, V.

    1995-01-01

    Alongside culture change, CRINE's other challenge is producing the right tools for the North Sea industry to change its traditional method of operation. CRINE, an acronym for Cost Reduction Initiative for the New Era, is an industry-wide program now underway in the UK Continental Shelf whose main objective is to achieve thirty percent or more savings in capital costs and to half operating costs over the next few years. These tools cover functional specifications, common working practices and quality. Turning these tools into deliverables, and on time, was a mixture of painstaking work and willingness by people to adapt to the needs of the task

  2. A COGNITIVE-BEHAVIOURAL GROUP TREATMENT IMPROVED WORK ABILITY IN PATIENTS WITH SEVERE FUNCTIONAL SOMATIC SYNDROMES

    DEFF Research Database (Denmark)

    Schröder, Andreas; Ørnbøl, Eva; Jensen, Jens Søndergaard

    2014-01-01

    Objective: Functional somatic syndromes (FSS) such as fibromyalgia, irritable bowel and chronic fatigue syndrome often disrupt employment and may lead to long-term dependence on social benefits and permanently reduced work ability. Cognitive-behavioural treatments (CBT) relief symptoms and improve...... before to 3 years after treatment by means of random effects modelling allowing individual levels and slopes. Results: Compared with the general population, FSS patients showed a continuous decline in self-support, leading to markedly reduced work ability at trial entry. In the following years, EUC...

  3. Dynamic links between theta executive functions and alpha storage buffers in auditory and visual working memory.

    Science.gov (United States)

    Kawasaki, Masahiro; Kitajo, Keiichi; Yamaguchi, Yoko

    2010-05-01

    Working memory (WM) tasks require not only distinct functions such as a storage buffer and central executive functions, but also coordination among these functions. Neuroimaging studies have revealed the contributions of different brain regions to different functional roles in WM tasks; however, little is known about the neural mechanism governing their coordination. Electroencephalographic (EEG) rhythms, especially theta and alpha, are known to appear over distributed brain regions during WM tasks, but the rhythms associated with task-relevant regional coupling have not been obtained thus far. In this study, we conducted time-frequency analyses for EEG data in WM tasks that include manipulation periods and memory storage buffer periods. We used both auditory WM tasks and visual WM tasks. The results successfully demonstrated function-specific EEG activities. The frontal theta amplitudes increased during the manipulation periods of both tasks. The alpha amplitudes increased during not only the manipulation but also the maintenance periods in the temporal area for the auditory WM and the parietal area for the visual WM. The phase synchronization analyses indicated that, under the relevant task conditions, the temporal and parietal regions show enhanced phase synchronization in the theta bands with the frontal region, whereas phase synchronization between theta and alpha is significantly enhanced only within the individual areas. Our results suggest that WM task-relevant brain regions are coordinated by distant theta synchronization for central executive functions, by local alpha synchronization for the memory storage buffer, and by theta-alpha coupling for inter-functional integration.

  4. Characterizing Cognitive Aging of Working Memory and Executive Function in Animal Models

    Directory of Open Access Journals (Sweden)

    Jennifer Lynn Bizon

    2012-09-01

    Full Text Available Executive functions supported by prefrontal cortical systems provide essential control and planning mechanisms to guide goal-directed behavior. As such, age-related alterations in executive functions can mediate profound and widespread deficits on a diverse array of neurocognitive processes. Many of the critical neuroanatomical and functional characteristics of prefrontal cortex are preserved in rodents, allowing for meaningful cross-species comparisons relevant to the study of cognitive aging. In particular, as rodents lend themselves to genetic, cellular and biochemical approaches, rodent models of executive function stand to significantly contribute to our understanding of the critical neurobiological mechanisms that mediate decline of executive processes across the lifespan. Moreover, rodent analogues of executive functions that decline in human aging represent an essential component of a targeted, rational approach for developing and testing effective treatment and prevention therapies for age-related cognitive decline. This paper reviews behavioral approaches used to study executive function in rodents, with a focus on those assays that share a foundation in the psychological and neuroanatomical constructs important for human aging. A particular emphasis is placed on behavioral approaches used to assess working memory and cognitive flexibility, which are sensitive to decline with age across species and for which strong rodent models currently exist. In addition, other approaches in rodent behavior that have potential for providing analogues to functions that reliably decline to human aging (e.g., information processing speed are discussed.

  5. A Simple Hydrogen Electrode

    Science.gov (United States)

    Eggen, Per-Odd

    2009-01-01

    This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements…

  6. The Composite Insertion Electrode

    DEFF Research Database (Denmark)

    Atlung, Sven; Zachau-Christiansen, Birgit; West, Keld

    1984-01-01

    The specific energy obtainable by discharge of porous insertion electrodes is limited by electrolyte depletion in thepores. This can be overcome using a solid ion conductor as electrolyte. The term "composite" is used to distinguishthese electrodes from porous electrodes with liquid electrolyte...

  7. Lithium alloy negative electrodes

    Science.gov (United States)

    Huggins, Robert A.

    The 1996 announcement by Fuji Photo Film of the development of lithium batteries containing convertible metal oxides has caused a great deal of renewed interest in lithium alloys as alternative materials for use in the negative electrode of rechargeable lithium cells. The earlier work on lithium alloys, both at elevated and ambient temperatures is briefly reviewed. Basic principles relating thermodynamics, phase diagrams and electrochemical properties under near-equilibrium conditions are discussed, with the Li-Sn system as an example. Second-phase nucleation, and its hindrance under dynamic conditions plays an important role in determining deviations from equilibrium behavior. Two general types of composite microstructure electrodes, those with a mixed-conducting matrix, and those with a solid electrolyte matrix, are discussed. The Li-Sn-Si system at elevated temperatures, and the Li-Sn-Cd at ambient temperatures are shown to be examples of mixed-conducting matrix microstructures. The convertible oxides are an example of the solid electrolyte matrix type. Although the reversible capacity can be very large in this case, the first cycle irreversible capacity required to convert the oxides to alloys may be a significant handicap.

  8. Study of clean and ion bombardment damaged silver single crystal surfaces by work function measurements

    International Nuclear Information System (INIS)

    Chelvayohan, N.

    1982-06-01

    Work function values of the (110), (100) and (111) faces of silver single crystal were measured by the photoelectric emission method and found to be 4.14 +- 0.04 eV, 4.22 +-0.04 eV and 4.46 +- 0.02 eV respectively. Oxygen adsorption on the faces were studied by surface potential measurement. Strong oxygen adsorption was observed on (110) and (100) faces, whereas the (111) face was found to be inert for oxygen adsorption. Oxygen adsorption on the (111) face damaged by argon ion bombardment was also investigated. The above results were compared with those of early reported work function and oxygen adsorption values. (U.K.)

  9. Oscillatory lower body negative pressure impairs working memory task-related functional hyperemia in healthy volunteers.

    Science.gov (United States)

    Merchant, Sana; Medow, Marvin S; Visintainer, Paul; Terilli, Courtney; Stewart, Julian M

    2017-04-01

    Neurovascular coupling (NVC) describes the link between an increase in task-related neural activity and increased cerebral blood flow denoted "functional hyperemia." We previously showed induced cerebral blood flow oscillations suppressed functional hyperemia; conversely functional hyperemia also suppressed cerebral blood flow oscillations. We used lower body negative pressure (OLBNP) oscillations to force oscillations in middle cerebral artery cerebral blood flow velocity (CBFv). Here, we used N-back testing, an intellectual memory challenge as a neural activation task, to test the hypothesis that OLBNP-induced oscillatory cerebral blood flow can reduce functional hyperemia and NVC produced by a working memory task and can interfere with working memory. We used OLBNP (-30 mmHg) at 0.03, 0.05, and 0.10 Hz and measured spectral power of CBFv at all frequencies. Neither OLBNP nor N-back, alone or combined, affected hemodynamic parameters. 2-Back power and OLBNP individually were compared with 2-back power during OLBNP. 2-Back alone produced a narrow band increase in oscillatory arterial pressure (OAP) and oscillatory cerebral blood flow power centered at 0.0083 Hz. Functional hyperemia in response to 2-back was reduced to near baseline and 2-back memory performance was decreased by 0.03-, 0.05-, and 0.10-Hz OLBNP. OLBNP alone produced increased oscillatory power at frequencies of oscillation not suppressed by added 2-back. However, 2-back preceding OLBNP suppressed OLBNP power. OLBNP-driven oscillatory CBFv blunts NVC and memory performance, while memory task reciprocally interfered with forced CBFv oscillations. This shows that induced cerebral blood flow oscillations suppress functional hyperemia and functional hyperemia suppresses cerebral blood flow oscillations. NEW & NOTEWORTHY We show that induced cerebral blood flow oscillations suppress functional hyperemia produced by a working memory task as well as memory task performance. We conclude that oscillatory

  10. Highly transparent vanadium oxide-graded indium zinc oxide electrodes for flexible organic solar cells

    International Nuclear Information System (INIS)

    Ko, Eun-Hye; Kim, Han-Ki

    2016-01-01

    We investigated characteristics of amorphous V_2O_5-graded InZnO (IZO) films to use as a flexible anode for flexible organic solar cells (FOSCs). Graded sputtering of the V_2O_5 layer on the IZO layer produced V_2O_5-graded IZO anodes (VGIZO) with a sheet resistance of 42.14 Ω/square, a resistivity of 6.32 × 10"−"4 Ω cm, and an optical transmittance of 82.15%, as well as good mechanical flexibility. In addition, the VGIZO electrode showed a greater work function of 5.2 eV than that (4.9 eV) of an IZO anode, which is beneficial for hole extraction from an organic active layer. Due to the higher work function of the VGIZO electrodes, FOSCs fabricated on the flexible VGIZO anode exhibited a higher power conversion efficiency 2.753% than that of FOSCs on the IZO anode. This indicates that the V_2O_5 graded sputtering is a promising technique to increase the work function of the IZO anode without change in sheet resistance and transmittance. - Highlights: • Transparent and flexible V_2O_5 graded IZO (VGIZO) electrodes. • High work function of VGIZO electrodes • The VGIZO film is a promising flexible anode for flexible organic solar cells.

  11. Long Life Nickel Electrodes for Nickel-Hydrogen Cells: Fiber Substrates Nickel Electrodes

    Science.gov (United States)

    Rogers, Howard H.

    2000-01-01

    Samples of nickel fiber mat electrodes were investigated over a wide range of fiber diameters, electrode thickness, porosity and active material loading levels. Thickness' were 0.040, 0.060 and 0.080 inches for the plaque: fiber diameters were primarily 2, 4, and 8 micron and porosity was 85, 90, and 95%. Capacities of 3.5 in. diameter electrodes were determined in the flooded condition with both 26 and 31% potassium hydroxide solution. These capacity tests indicated that the highest capacities per unit weight were obtained at the 90% porosity level with a 4 micron diameter fiber plaque. It appeared that the thinner electrodes had somewhat better performance, consistent with sintered electrode history. Limited testing with two-positive-electrode boiler plate cells was also carried out. Considerable difficulty with constructing the cells was encountered with short circuits the major problem. Nevertheless, four cells were tested. The cell with 95% porosity electrodes failed during conditioning cycling due to high voltage during charge. Discharge showed that this cell had lost nearly all of its capacity. The other three cells after 20 conditioning cycles showed capacities consistent with the flooded capacities of the electrodes. Positive electrodes made from fiber substrates may well show a weight advantage of standard sintered electrodes, but need considerably more work to prove this statement. A major problem to be investigated is the lower strength of the substrate compared to standard sintered electrodes. Problems with welding of leads were significant and implications that the electrodes would expand more than sintered electrodes need to be investigated. Loading levels were lower than had been expected based on sintered electrode experiences and the lower loading led to lower capacity values. However, lower loading causes less expansion and contraction during cycling so that stress on the substrate is reduced.

  12. More precise determination of work function based on Fermi–Dirac distribution and Fowler formula

    International Nuclear Information System (INIS)

    Changshi, Liu

    2014-01-01

    More precise numerical method to simulate current–voltage of metal at fixed temperature is presented in this paper. The new algorithm for the simulation has been developed via Fermi–Dirac distribution step by step. These calculated characteristics are shown to remain in excellent agreement with the experimental ones, taken for a range of different metals, which strong supports the validity of the model. It is also shown that based on the Fowler formula, higher precise work function can be determined.

  13. Microfabrication process for patterning metallic lithium encapsulated electrodes

    International Nuclear Information System (INIS)

    Oukassi, Sami; Dunoyer, Nicolas; Salot, Raphael; Martin, Steve

    2009-01-01

    This work presents recent achievements concerning thin film encapsulation of metallic lithium negative electrode. In the context of this study, the encapsulation stack includes polymer and dielectric layers combined in such way to optimize barrier performances of the whole structure towards oxygen and water vapor permeation. The first part of this work is dedicated to the description of the barrier stack architecture and properties. A second part presents the application of a microfabrication process to the metallic lithium negative electrode and barrier stack so as to have very small features (100 μm x 100 μm patterns). The microfabrication process includes several steps of photolithography and etching (dry and wet) blocks, which allows us to reach the target critical dimensions. These results show a method of patterning functional metallic lithium. It demonstrates the feasibility of energy sources miniaturization which is an important issue in the field of autonomous and wireless sensor networks.

  14. Functional challenges among late effects cancer survivors: a preliminary report on work engagement issues.

    Science.gov (United States)

    Crist, Patricia

    2013-01-01

    While the cancer survivor rate is nearly 68% now, intervention regimens may leave residual conditions that impact engagement in work and various life tasks. Survivors are underemployed and report stigmatizing attitudes among co-workers. When late effects from cancer arise over 10 years later, the impact on individuals in the prime of their productive employment life is evident. Assisting these individuals begins with awareness of late effects in order to create work-related, adaptive strategies. Sixteen adult cancer survivors experiencing late effects completed the Occupational Self Assessment (Version 2.2) and the Quality of Life-Cancer Survivors (QOL-CS). Knowledge of functional problems secondary to recognized late effects medical conditions reported in the literature was utilized to sort items according to professional definitions of work, performance skills and performance patterns. Late effects survivors reported that cancer illness and treatment has negatively impacted their employment. Individual response to the impact of late effects is highly variant. "Getting things done" and physical energy limitations are most pronounced. Cancer survivors report lower competence in significant work-related skills and patterns. Quality of life associated with the aftereffects of fatigue, aches and pain, and sleep changes are the lowest. Responses range across the 16 survivors to both performance skills and performance patterns. Cancer survivorship has clearly interfered with employment. An interdisciplinary focus on meaningful engagement in life activities, particularly work is crucial to support survivors through advocacy, adaptation and positive change to focus on engaging the work talents and gifts for all cancer survivors.

  15. Improving the work function of the niobium surface of SRF cavities by plasma processing

    International Nuclear Information System (INIS)

    Tyagi, P.V.; Doleans, M.; Hannah, B.; Afanador, R.; McMahan, C.; Stewart, S.; Mammosser, J.; Howell, M.; Saunders, J.; Degraff, B.; Kim, S.-H.

    2016-01-01

    Highlights: • An in situ plasma processing for SNS SRF cavities has been developed to remove hydrocarbons from cavity surface. • Reactive oxygen plasma is very effective to remove hydrocarbons from niobium top surface. • Reactive oxygen plasma processing increases the work function of niobium surface in the range of 0.5–1.0 eV. • It was observed that hydrocarbons can migrate at plasma cleaned top surface from near surface regions when waiting in vacuum at room temperature. • Multiple cycles of plasma processing with waiting periods in between was found beneficial to mitigate such hydrocarbons migration at plasma cleaned surface. - Abstract: An in situ plasma processing technique using chemically reactive oxygen plasma to remove hydrocarbons from superconducting radio frequency cavity surfaces at room temperature has been developed at the spallation neutron source, at Oak Ridge National Laboratory. To understand better the interaction between the plasma and niobium surface, surface studies on small samples were performed. In this article, we report the results from those surface studies. The results show that plasma processing removes hydrocarbons from top surface and improves the surface work function by 0.5–1.0 eV. Improving the work function of RF surface of cavities can help to improve their operational performance.

  16. Large work function difference driven electron transfer from electrides to single-walled carbon nanotubes

    KAUST Repository

    Menamparambath, Mini Mol

    2014-06-23

    A difference in work function plays a key role in charge transfer between two materials. Inorganic electrides provide a unique opportunity for electron transfer since interstitial anionic electrons result in a very low work function of 2.4-2.6 eV. Here we investigated charge transfer between two different types of electrides, [Ca2N]+·e- and [Ca 24Al28O64]4+·4e-, and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca2N]+·e- with open 2-dimensional electron layers was more effective in donating electrons to SWNTs than closed cage structured [Ca24Al28O64] 4+·4e- due to the higher electron concentration (1.3 × 1022 cm-3) and mobility (∼200 cm 2 V-1 s-1 at RT). A non-covalent conjugation enhanced near-infrared fluorescence of SWNTs as high as 52%. The field emission current density of electride-SWNT-silver paste dramatically increased by a factor of 46000 (14.8 mA cm-2) at 2 V μm-1 (3.5 wt% [Ca2N]+·e-) with a turn-on voltage of 0.85 V μm-1. This journal is © the Partner Organisations 2014.

  17. Layer-dependent band alignment and work function of few-layer phosphorene.

    Science.gov (United States)

    Cai, Yongqing; Zhang, Gang; Zhang, Yong-Wei

    2014-10-20

    Using first-principles calculations, we study the electronic properties of few-layer phosphorene focusing on layer-dependent behavior of band gap, work function band alignment and carrier effective mass. It is found that few-layer phosphorene shows a robust direct band gap character, and its band gap decreases with the number of layers following a power law. The work function decreases rapidly from monolayer (5.16 eV) to trilayer (4.56 eV), and then slowly upon further increasing the layer number. Compared to monolayer phosphorene, there is a drastic decrease of hole effective mass along the ridge (zigzag) direction for bilayer phosphorene, indicating a strong interlayer coupling and screening effect. Our study suggests that 1). Few-layer phosphorene with a layer-dependent band gap and a robust direct band gap character is promising for efficient solar energy harvest. 2). Few-layer phosphorene outperforms monolayer counterpart in terms of a lighter carrier effective mass, a higher carrier density and a weaker scattering due to enhanced screening. 3). The layer-dependent band edges and work functions of few-layer phosphorene allow for modification of Schottky barrier with enhanced carrier injection efficiency. It is expected that few-layer phosphorene will present abundant opportunities for a plethora of new electronic applications.

  18. Water on TiO2 studied by work function change: adsorption in cycles

    International Nuclear Information System (INIS)

    Bundaleski, Nenad; Silva, Ana G; Jean-Shaw, Bobbie; Teodoro, Orlando; Moutinho, Augusto

    2013-01-01

    The nature of water adsorption on TiO 2 (110) rutile surface attracts a lot of attention for quite some time. In spite of the considerable experimental and theoretical efforts a lot of details remain unclear. We have been using work function study to follow the adsorption of water on TiO 2 at room temperature, and interpreted the results in terms of fast dissociative adsorption on bridging oxygen vacancies (BOV) and much slower non-dissociative adsorption on Ti 5f rows. Additionally, we concluded that water from Ti 5f rows efficiently desorbs at room temperature which is not the case for BOV adsorption sites. Here we propose a novel experimental approach which consists of monitoring in real-time the work function change during cycles of water adsorption. Since desorption at BOVs does not take place at room temperature, this method allows us to resolve the adsorption dynamics on the two adsorption sites. The first results changed our understanding of the phenomenon: we show that both, adsorption on BOVs and Ti 5f are both very fast. Additionally, slow exponential decay of the work function is observed, which is not directly related to water adsorption. The possible explanation of the third slow contribution could be related to the migration of hydrogen atoms along the bridging oxygen rows.

  19. `Sex' – It's not only Women's Work: A Case for Refocusing on the Functional Role that Sex Plays in Work for both Women and Men

    OpenAIRE

    Uretsky, Elanah

    2014-01-01

    Mention of the term sex work often invokes images of marginalized women at risk for HIV infection. Such images, however, are counterintuitive to the functional role intended by the movement that spawned use of the terms `sex work' and `sex worker'. This article looks at the sexual practices of men in urban China to argue for a return to a functional definition of `sex work', which was originally meant to legitimize the role sex plays in work. The progenitors of this movement intended to use `...

  20. Spanish adaptation of the internal functioning of the Work Teams Scale (QFI-22).

    Science.gov (United States)

    Ficapal-Cusí, Pilar; Boada-Grau, Joan; Torrent-Sellens, Joan; Vigil-Colet, Andreu

    2014-05-01

    The aim of this article is to develop the Spanish adaptation of the internal functioning of Work Teams Scale (QFI-22). The scale was adapted from the French version, and was applied to a sample of 1,055 employees working for firms operating in Spain. The article analyses the internal structure (exploratory and confirmatory factor analysis) and internal consistency, and provides convergent validity evidence of the scale. The QFI-22 scale shows the same internal structure as the original. Factor analysis confirmed the existence of two factors: interpersonal support and team work management, with good internal consistency coefficients (α1 = .93, α2 = .92). Regarding validity evidence, the QFI-22 scale has significant correlations with other correlates and alternative scales used for comparison purposes. The two factors correlated positively with team vision, participation safety, task orientation and support for innovation (Team Climate Inventory, TCI scale), with progressive culture (Organisational Culture, X-Y scale), and with creating change, customer focus and organisational learning (Denison Organizational Culture Survey, DOCS scale). In contrast, the two factors correlated negatively with traditional culture (X-Y scale). The QFI-22 scale is a useful instrument for assessing the internal functioning of work teams.

  1. Constructing a working taxonomy of functional Ada software components for real-time embedded system applications

    Science.gov (United States)

    Wallace, Robert

    1986-01-01

    A major impediment to a systematic attack on Ada software reusability is the lack of an effective taxonomy for software component functions. The scope of all possible applications of Ada software is considered too great to allow the practical development of a working taxonomy. Instead, for the purposes herein, the scope of Ada software application is limited to device and subsystem control in real-time embedded systems. A functional approach is taken in constructing the taxonomy tree for identified Ada domain. The use of modular software functions as a starting point fits well with the object oriented programming philosophy of Ada. Examples of the types of functions represented within the working taxonomy are real time kernels, interrupt service routines, synchronization and message passing, data conversion, digital filtering and signal conditioning, and device control. The constructed taxonomy is proposed as a framework from which a need analysis can be performed to reveal voids in current Ada real-time embedded programming efforts for Space Station.

  2. Dependence of Au- production upon the target work function in a plasma-sputter-type negative ion source

    International Nuclear Information System (INIS)

    Okabe, Yushirou; Sasao, Mamiko; Fujita, Junji; Yamaoka, Hitoshi; Wada, Motoi.

    1991-01-01

    A method to measure the work function of the target surface in a plasma-sputter-type negative ion source has been developed. The method can determine the work function by measuring the photoelectric current induced by two lasers (He-Ne, Ar + laser). The dependence of Au - production upon the work function of the target surface in the ion source was studied using this method. The time variation of the target work function and Au - production rate were measured during the cesium coverage decrease due to the plasma ion sputtering. The observed minimum work function of a cesiated gold surface in an Ar plasma was 1.3 eV. At the same time, the negative ion production rate (Au - current/target current) took the maximum value. The negative ion production rate indicated the same dependence on the incident ion energy as that of the sputtering rate when the work function was constant. (author)

  3. Local work function analysis of Pt/TiO2 photocatalyst by a Kelvin probe force microscope

    International Nuclear Information System (INIS)

    Hiehata, K; Sasahara, A; Onishi, H

    2007-01-01

    Nanometre-sized Pt clusters were prepared on a TiO 2 (110)-(1 x 1) surface, and the lateral distribution of work function was examined by using a Kelvin probe force microscope. Local work function on the Pt clusters was smaller than that on the surrounding TiO 2 surface. Assuming that the dipole moments which perturb the work function are produced by uneven electron distribution, the decrease of the work function indicates electron transfer from the clusters to the TiO 2 surface. After decomposition of pivalate anions on the surfaces by UV irradiation, the work function increased on some Pt clusters. It is known that holes photoexcited in TiO 2 attach to pivalate anions to cause a decomposition reaction. Hence the increase of the observed work function by UV irradiation can be ascribed to the trapping of the accompanying electrons to the Pt clusters

  4. Numerical Characterization of Intraoperative and Chronic Electrodes in Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Alessandra ePaffi

    2015-02-01

    Full Text Available Intraoperative electrode is used in the Deep Brain stimulation (DBS technique to pinpoint the brain target and to choose the best parameters for the stimulating signal. However, when the intraoperative electrode is replaced with the chronic one, the observed effects do not always coincide with predictions.To investigate the causes of such discrepancies, in this work, a 3D model of the basal ganglia has been considered and realistic models of both intraoperative and chronic electrodes have been developed and numerically solved.Results of simulations on the electric potential and the activating function along neuronal fibers show that the different geometries and sizes of the two electrodes do not change shapes and polarities of these functions, but only the amplitudes. A similar effect is caused by the presence of different tissue layers (edema or glial tissue in the peri-electrode space. On the contrary, a not accurate positioning of the chronic electrode with respect to the intraoperative one (electric centers not coincident may induce a complete different electric stimulation on some groups of fibers.

  5. Multi electrode semiconductors detectors

    CERN Document Server

    Amendolia, S R; Bertolucci, Ennio; Bosisio, L; Bradaschia, C; Budinich, M; Fidecaro, F; Foà, L; Focardi, E; Giazotto, A; Giorgi, M A; Marrocchesi, P S; Menzione, A; Ristori, L; Rolandi, Luigi; Scribano, A; Stefanini, A; Vincelli, M L

    1981-01-01

    Detectors with very high space resolution have been built in this laboratory and tested at CERN in order to investigate their possible use in high energy physics experiments. These detectors consist of thin layers of silicon crystals acting as ionization chambers. Thin electrodes, structured in strips or in more fancy shapes are applied to their surfaces by metal coating. The space resolution which could be reached is of the order of a few microns. An interesting feature of these solid state detectors is that they can work under very high or low external pressure or at very low temperature. The use of these detectors would strongly reduce the dimensions and the cost of high energy experiments. (3 refs).

  6. Multi electrode semiconductor detectors

    International Nuclear Information System (INIS)

    Amendolia, S.R.; Batignani, G.; Bertolucci, E.; Bosisio, L.; Budinich, M.; Bradaschia, C.; Fidecaro, F.; Foa, L.; Focardi, E.; Giazotto, A.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Rolandi, L.; Scribano, A.; Stefanini, A.; Vincelli, M.L.

    1981-01-01

    Detectors with very high space resolution have been built in the laboratory and tested at CERN in order to investigate their possible use in high energy physics experiments. These detectors consist of thin layers of silicon crystals acting as ionization chambers. Thin electrodes, structured in strips or in more fancy shapes are applied to their surfaces by metal coating. The space resolution which could be reached is of the order of a few microns. An interesting feature of these solid state detectors is that they can work under very high or low external pressure or at very low temperature. The use of these detectors would strongly reduce the dimensions and the cost of high energy experiments. (Auth.)

  7. Insulating electrodes: a review on biopotential front ends for dielectric skin–electrode interfaces

    International Nuclear Information System (INIS)

    Spinelli, Enrique; Haberman, Marcelo

    2010-01-01

    Insulating electrodes, also known as capacitive electrodes, allow acquiring biopotentials without galvanic contact with the body. They operate with displacement currents instead of real charge currents, and the electrolytic electrode–skin interface is replaced by a dielectric film. The use of insulating electrodes is not the end of electrode interface problems but the beginning of new ones: coupling capacitances are of the order of pF calling for ultra-high input impedance amplifiers and careful biasing, guarding and shielding techniques. In this work, the general requirements of front ends for capacitive electrodes are presented and the different contributions to the overall noise are discussed and estimated. This analysis yields that noise bounds depend on features of the available devices as current and voltage noise, but the final noise level also depends on parasitic capacitances, requiring a careful shield and printed circuit design. When the dielectric layer is placed on the skin, the present-day amplifiers allow achieving noise levels similar to those provided by wet electrodes. Furthermore, capacitive electrode technology allows acquiring high quality ECG signals through thin clothes. A prototype front end for capacitive electrodes was built and tested. ECG signals were acquired with these electrodes in direct contact with the skin and also through cotton clothes 350 µm thick. They were compared with simultaneously acquired signals by means of wet electrodes and no significant differences were observed between both output signals

  8. Sex differences in physical and mental functioning of Japanese civil servants: explanations from work and family characteristics.

    Science.gov (United States)

    Sekine, Michikazu; Chandola, Tarani; Martikainen, Pekka; Marmot, Michael; Kagamimori, Sadanobu

    2010-12-01

    Poor physical and mental functioning are more common among women than men and those with disadvantaged work and family characteristics. This study aims to clarify whether sex differences in health functioning can be explained by sex differences in work and family characteristics. The subjects were 3787 civil servants (2525 men and 1262 women), aged 20-65, working in a local government on the west coast of Japan. A questionnaire survey was conducted in January 2003. Low employment grade, high demands, long work hours, shift work, being unmarried, having no young children, high family-to-work conflict and high work-to-family conflict were more common among women than men and were independently associated with poor physical and mental functioning. The age-adjusted odds ratios (ORs) of women for poor health functioning were 1.80 for poor physical functioning and 1.77 for poor mental functioning. When adjusted for employment grade and work characteristics (control, demand, support, work hours, and shift work), the sex differences in health functioning attenuated. When adjusted for family characteristics (family structure and work-family conflicts), the sex differences in health functioning further attenuated and were no longer statistically significant. Sex differences in family characteristics contributed more to sex difference in mental functioning than sex differences in work characteristics. Japan belongs to conservative welfare regimes. In such countries, men are able to concentrate on their work with relative freedom from their family tasks and responsibilities, whereas women feel difficulties in maintaining their work-life balances. Such sex differences in work- and family-related stresses may contribute to sex difference in health. Longitudinal research is necessary to clarify the causal nature of these associations. Copyright © 2010 Elsevier Ltd. All rights reserved.