WorldWideScience

Sample records for applied electrochemistry prikladnaya

  1. Electrochemistry

    International Nuclear Information System (INIS)

    In my view, Rieger's Electrochemistry falls in the category of excellent textbooks. It is very well written and presents the more challenging concepts of electrochemistry logically and lucidly. This book would be an excellent choice for use in an advanced undergraduate or first-year graduate-level course in general electrochemistry. The emphasis is on the physical aspects of electrochemistry, perhaps reflecting the author's primary interest in mechanistic studies. For a course emphasizing the analytical aspects of electrochemistry, considerable supplementation would be required and other, more appropriate textbooks are available

  2. Electrochemistry applied to biomass. Progress report, October 1980-September 1981

    Energy Technology Data Exchange (ETDEWEB)

    Chum, H. L. [ed.

    1982-04-01

    The electrochemical conversion of biomass-derived compounds, obtained through thermochemical pretreatments, into valuable organic chemicals, petrochemical substitutes, and energy-intensive chemicals is investigated. A hardwood-derived lignin obtained from ethanol extraction of the explosively depressurized aspen has been investigated. We have partially characterized this lignin material, and have also submitted it to electrolyses under controlled potential. The electrolytic conditions employed so far affect mainly the carbonyl groups of the ethanol-extracted steam-exploded aspen lignin. We have some evidence of demethoxylation and changed phenolic content after electrolysis. During product isolation, fractionation of the lignin occurs. The material with decreased methoxyl content may be suitable to replace phenol in phenol-formaldehyde-type resins. We are continuing these electrochemical and chemical investigations. Gel-permeation chromatography is being used to separate and characterize the several lignin fractions. In addition, we are carrying out electrolyses under more powerful reducing conditions which may lead to the cleavage of the main bonds in the lignin molecule (the ..beta..-0-4 ether linkages) producing monomeric and dimeric phenolic compounds. The electrochemistry and photoelectrochemistry of levulinic (4-oxo-pentanoic) acid, the major product of controlled degradation of cellulose by acids, have been investigated. This acid can be viewed as a major product of biomass thermochemical pretreatment or as a by-product of acid hydrolysis to fermentable sugars. Since this acid can be present in waste streams of biomass processing, we investigated the photoelectrochemical reactions of this acid on slurries composed of semiconductor/metal particles. The semiconductor investigated was undoped n-TiO/sub 2/, as anatase, anatase-rutile mixture, or rutile.

  3. Supramolecular Electrochemistry

    Science.gov (United States)

    Kaifer, Angel E.; Gomez-Kaifer, Marielle

    1999-12-01

    This book describes the electrochemical behavior of supramolecular systems. Special emphasis will be given to the electrochemistry of host-guest complexes, monolayer and multilayer assemblies, dendrimers, and other supramolecular assemblies. A fundamental theme throughout the book is to explore the effects that supramolecular structure exerts on the thermodynamics and kinetics of electrochemical reactions. Conversely, attention will be placed to the various ways in which electrochemical or redox conversions can be utilized to control or affect the structure or properties of supramolecular systems. This first book on this topic will be of value for graduate students and advanced researchers in both electrochemistry and supramolecular chemistry.

  4. Applied Electrochemistry of Aluminum

    DEFF Research Database (Denmark)

    Li, Qingfeng; Qiu, Zhuxian

    electrolytes. The book is an updated review of the technological advances in the fields of electrolytic production and refining of metals, electroplating, anodizing and other electrochemical surface treatments, primary and secondary batteries, electrolytic capacitors; corrosion and protection and others....

  5. Analytical and physical electrochemistry

    CERN Document Server

    Girault, Hubert H

    2004-01-01

    The study of electrochemistry is pertinent to a wide variety of fields, including bioenergetics, environmental sciences, and engineering sciences. In addition, electrochemistry plays a fundamental role in specific applications as diverse as the conversion and storage of energy and the sequencing of DNA.Intended both as a basic course for undergraduate students and as a reference work for graduates and researchers, Analytical and Physical Electrochemistry covers two fundamental aspects of electrochemistry: electrochemistry in solution and interfacial electrochemistry. By bringing these two subj

  6. Modern electrochemistry

    CERN Document Server

    Bockris, John O'M

    2007-01-01

    about the First Edition: `A superbly written teaching book which should become indispensable to every student of electrochemistry.' Journal of the American Chemical Society `A truly extraordinary achievement ... An enormous body of electrochemical knowledge and a wealth of stunningly penetrating detail.' Journal of the Electrochemical Society `A must.' Nature about the second edition: `These original, stimulating and informative volumes offer an unusual approach and inter alia provide an excellent entrée to the field for the non-specialist.' Emeritus Professor D

  7. Composite Electrodes in Electrochemistry

    Czech Academy of Sciences Publication Activity Database

    Šebková, Světlana; Navrátil, Tomáš; Kopanica, M.

    Galway : National University of Ireland , 2004. s. 72. [International Conference on Electroanalysis /10./. 06.06.2004-10.06.2004, Galway] Keywords : electrochemistry * modern electroanalytical sensors * silver composite electrode Subject RIV: CG - Electrochemistry

  8. Applications of electrochemistry and nanotechnology in biology and medicine II

    CERN Document Server

    Eliaz, Noam

    2011-01-01

    The study of electrochemical nanotechnology has emerged as researchers apply electrochemistry to nanoscience and nanotechnology. These two related volumes in the Modern Aspects of Electrochemistry Series review recent developments and breakthroughs in the specific application of electrochemistry and nanotechnology to biology and medicine. Internationally renowned experts contribute chapters that address both fundamental and practical aspects of several key emerging technologies in biomedicine, such as the processing of new biomaterials, biofunctionalization of surfaces, characterization of bio

  9. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    2001-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  10. Silicon: electrochemistry and luminescence

    OpenAIRE

    Kooij, Ernst Stefan

    2001-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescence from porous silicon is investigated. Both under cathodic and anodic polarization emission can be observed in the presence of oxidizing and reducing agents, respectively. Also in indifferent electrol...

  11. Instrumental methods in electrochemistry

    CERN Document Server

    Pletcher, D; Peat, R

    2010-01-01

    Using 372 references and 211 illustrations, this book underlines the fundamentals of electrochemistry essential to the understanding of laboratory experiments. It treats not only the fundamental concepts of electrode reactions, but also covers the methodology and practical application of the many versatile electrochemical techniques available.Underlines the fundamentals of electrochemistry essential to the understanding of laboratory experimentsTreats the fundamental concepts of electrode reactionsCovers the methodology and practical application of the many ve

  12. Electrochemistry in supercritical fluids

    OpenAIRE

    Branch, Jack A.; Bartlett, Philip N.

    2015-01-01

    A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ra...

  13. Electrochemistry of nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Bartošík, Martin

    2012-01-01

    Roč. 112, č. 6 (2012), s. 3427-3481. ISSN 0009-2665 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA MŠk(CZ) ME09038; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : nucleic acids electrochemistry * DNA biosensors * DNA damage Subject RIV: BO - Biophysics Impact factor: 41.298, year: 2012

  14. Applications of electrochemistry in medicine

    CERN Document Server

    Schlesinger, Mordechay

    2013-01-01

    Medical Applications of Electrochemistry, a volume of the series Modern Aspects of Electrochemistry, illustrates the interdisciplinary nature of modern science by indicating the many current issues in medicine that are susceptible to solution by electrochemical methods. This book also suggests how personalized medicine can develop.

  15. Electrochemistry and Storage

    Science.gov (United States)

    Thaller, L. H.

    1984-01-01

    The term electrochemistry implies the use of devices that convert chemical energy into electrical energy and sometimes vice versa. These devices are usually composed of some number of individual cells that are connected together to form a battery. In the cases where these devices cannot be electrically recharged they are usually referred to as primary batteries, whereas if these batteries can be charged and recharged repeatedly, they are called secondary batteries. The past and present uses of primary and secondary batteries in aerospace applications are discussed.

  16. Electrochemistry in supercritical fluids.

    Science.gov (United States)

    Branch, Jack A; Bartlett, Philip N

    2015-12-28

    A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide-acetonitrile and supercritical HFCs. PMID:26574527

  17. Dynamic Electrochemistry: Methodology and Applications.

    Science.gov (United States)

    Johnson, Dennis C.; And Others

    1984-01-01

    Reviews literature dealing with novel developments or important trends in electrochemistry. Areas examined include mass transfer, electrode kinetics, surface effects, chemically modified electrodes, coulostatic/galvanostatic methods, bioelectrochemistry, spectroelectrochemistry, and electrode instrumentation. Books, textbooks, and literature…

  18. Determination of Lead by Electrochemistry

    Institute of Scientific and Technical Information of China (English)

    HE YuFeng; ZHANG Zhang; MA YongJun; KANG JingWan

    2001-01-01

    @@ Lead is one of the poisonous trace element for human body. It is important to find a way for measuring content of lead. Deternination of lead by electrochemistry is one of a method[1]. In this paper, lead is determined by single-sweep polarography. The absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) complex with lead ion has also been studied.In Na2B4O7-NaOH solution with pH=l 0.5, the reduction peaks of the ligand are P1 (Ep1=-0.38V), P2 (Ep2=-1.04V), which potentials are obtained vs. S.C.E. When lead ion has been added into above solution. The peak current of P1 and P2 decrease, and a new reduction peak P3 (Ep3=-1.10 V) appears. It shows that the TPPS4-Pb(Ⅱ) complex forms,and this method can be applied to study the complex.

  19. Determination of Lead by Electrochemistry

    Institute of Scientific and Technical Information of China (English)

    HE; YuFeng

    2001-01-01

    Lead is one of the poisonous trace element for human body. It is important to find a way for measuring content of lead. Deternination of lead by electrochemistry is one of a method[1]. In this paper, lead is determined by single-sweep polarography. The absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) complex with lead ion has also been studied.In Na2B4O7-NaOH solution with pH=l 0.5, the reduction peaks of the ligand are P1 (Ep1=-0.38V), P2 (Ep2=-1.04V), which potentials are obtained vs. S.C.E. When lead ion has been added into above solution. The peak current of P1 and P2 decrease, and a new reduction peak P3 (Ep3=-1.10 V) appears. It shows that the TPPS4-Pb(Ⅱ) complex forms,and this method can be applied to study the complex.……

  20. Electrochemistry of organic, bioactive compounds and biopolymers

    Czech Academy of Sciences Publication Activity Database

    Fojta, Miroslav; Navrátil, Tomáš

    2015-01-01

    Roč. 146, č. 5 (2015), s. 721-721. ISSN 0026-9247 Institutional support: RVO:68081707 ; RVO:61388955 Keywords : electrochemistry * biopolymers Subject RIV: CG - Electrochemistry Impact factor: 1.222, year: 2014

  1. Corrosive electrochemistry of jamesonite

    Institute of Scientific and Technical Information of China (English)

    邱冠周; 余润兰; 胡岳华; 覃文庆

    2004-01-01

    The corrosive electrochemistry of jamesonite (Pb4 FeSb6 S14) was studied by the electrochemical methods of cyclic voltammetry, polarization, and AC impedance. The electrochemical processes of jamesonite were controlled by the corrosive reactions, growth of the metal-deficient and sulfur-riched layer, passivation and breakdown of elemental sulfur film on the electrode surface. The corrosive potential(ψcorr) moves negatively, its corrosive current increases, and hydroxyl action becomes stronger with the rising pH value. The charge transfer resistance increases and the capacitance decreases due to the gradual growth of the metal-deficient and sulfur-riched layer on the mineral surface from -378 to 122 mV (vs SHE). Element sulfur layer is formed at the potential of 122 mV. The charge transfer resistance increases and its capacitance rises slowly due to the gradual breakdown of sulfur film at voltage from 222 mV to 422 mV. S2O2-3 and SO2-4 ions occur when the electrode potential is over 422 mV. Under basic condition, the hydrophobic hydroxyl precipitate occurs on jamesonite surface, so that its collectorless floatability is poor. Under the condition of pH 6.86, it can be deduced that the potential range of collectorless floatability of jamesonite is from 22 to 422 mV due to the passive action of the hydrophilic sulfur on jamesonite surface, and its optimum range of floatable potential is between 122 and 322 mV.

  2. LCEC: The Combination of Liquid Chromatography and Electrochemistry.

    Science.gov (United States)

    Kissinger, Peter T.

    1983-01-01

    Use of combined liquid chromatography and finite-current electrochemistry (LCEC) procedures are discussed. Also discusses the relationship between electroactivity and molecular structure, selectivity in LCEC, and LCEC applications. Because of its selectivity and low detection limits, the procedures are most often applied in biomedical and…

  3. The Electrochemistry of Natural Pigments

    Czech Academy of Sciences Publication Activity Database

    Sokolová, Romana; Degano, I.; Hromadová, Magdaléna; Pospíšil, Lubomír

    Ústí nad Labem : Best Servis, 2009 - (Barek, J.; Navrátil, T.), s. 99-99 ISBN 978-80-254-3997-5. [Moderní elektrochemické metody /29./. Jetřichovice (CZ), 25.05.2009-29.05.2009] R&D Projects: GA ČR(CZ) GA203/09/1607; GA ČR GA203/08/1157; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * natural pigments Subject RIV: CG - Electrochemistry

  4. 7. International Frumkin Symposium. Basic electrochemistry for science and technology. Abstracts. Part 2

    International Nuclear Information System (INIS)

    Modern tendencies of development of electrochemistry as in regions of fundamental investigations so in applied directions are presented. Basic themes of reports presented are: electrocatalysis and electrosynthesis, batteries and supercapacitors, corrosion and electrodeposition, electrolytes and membranes, biosensors and electroanalysis, nanoelectrochemistry

  5. New achievements and methodologies of electrochemistry and electrochemical engineering in the environmental protection and pollution control

    OpenAIRE

    Rodrigo, Manuel Andrés Rodrigo

    2014-01-01

    During the last decades, many applications of Electrochemistry and Electrochemical Engineering have arisen for the characterization and remediation of environmental problems. As a result, now­adays this subject has become one of the most interesting areas of research in applied electrochemistry, with hundreds of papers published every year and many applications already ava­ilable in the market. This special issue contains sixteen very valuable contributions on these topics, written by highly ...

  6. Factors that Prevent Learning in Electrochemistry

    Science.gov (United States)

    Schmidt, Hans-Jurgen; Marohn, Annette; Harrison, Allan G.

    2007-01-01

    Electrochemistry plays an important role in curricula, textbooks, and in everyday life. The purpose of the present study was to identify and understand secondary-school students' problems in learning electrochemistry at an introductory chemistry level. The investigation covered four areas: (a) electrolytes, (b) transport of electric charges in…

  7. Modern Aspects of Electrochemistry 40

    CERN Document Server

    White, Ralph E

    2007-01-01

    This volume in the acclaimed series Modern Aspects of Electrochemistry starts with a dedication to the late Professor Brian Conway who for 50 years helped to guide this series to its current prominence. The remainder of the volume is then devoted to the following topics: PEM fuel cells; the use of graphs in electrochemical reaction newtworks; nanomaterials in Lithium-ion batteries; direct methanolf fuel cells (two chapters); fuel cell catalyst layers. The book is for electrochemists, electrochemical engineers, fuel cell workers and energy generation workers.

  8. An Effective Approach to Teaching Electrochemistry.

    Science.gov (United States)

    Birss, Viola I.; Truax, D. Rodney

    1990-01-01

    An approach which may be useful for teaching electrochemistry in freshman college chemistry courses is presented. Discussed are the potential problems with teaching this subject and solutions provided by this approach. (CW)

  9. New materials for solid state electrochemistry

    International Nuclear Information System (INIS)

    Solid state electrochemistry is an interdisciplinary area, undergoing nowadays a fast development. It is related on the one hand to chemistry, and on the other hand to crystallography, solid state physics and materials science. In this paper structural and electrical properties of some families of new materials interesting for solid state electrochemistry are reviewed. Attention is focused essentially on ceramic and crystalline materials, glasses and polymers, displaying high ionic conductivity and potentially suitable for various applications in solid state electrochemical devices. (orig.)

  10. Electrochemistry "Discovery" Course for Undergraduates

    Science.gov (United States)

    May, Michael Alan; Gupta, Vijay K.

    1997-07-01

    We developed a chemistry selected topics course at Central State University, "Introduction to Laboratory Techniques in Electrochemistry" to: (1) give undergraduates hands-on experience with electrochemical measurements, (2) prepare students for summer research in Fuel Cell and Battery technology. Since students "learn by doing", the course is suitable for undergraduates from sophomore to senior levels. Students complete 6 laboratories, based on a "less is more" philosophy which emphasizes analytic and creative process rather than mandatory topical coverage. Eight electrochemical experiments are available: Construction of Zinc-Copper battery stacks, Lead Acid Battery discharge-charge cycles, Conductimetric titration of aspirin with Ammonium Hydroxide, Ion Selective Electrode determination of Fluoride in water, Cyclic Voltammetry of Potassium Ferricyanide solution, Cyclic Voltammetry of Sulfuric acid on Platinum working electrode, Anodic Stripping Voltammetry of Lead ion in solution, Differential Pulse Polarography of Lead ion in solution. Topics discussed in lecture include: chemical definitions, electrical definitions, Oxidation-Reduction reactions, Electrochemical series, Electrodes, Electrochemical Cells, direct Coulometry, electrolysis, electrochemical process efficiency, equilibrium Potentiometry, real Cell Voltages, Ion Selective Electrode types and designs, reference electrode designs, working electrode materials, pH buffers, Cyclic Voltammetry, Anodic Stripping Voltammetry, Polarography, differential pulse Polarography, and simple electrochemical instrumentation circuits.

  11. Electrochemistry and spectro-electrochemistry of dithizonatophenylmercury(II)

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: → CV and spectroelectrochemistry of dithizone and PhHgHDz, 3, is presented. → CV shows 3 has stable metal thioether (Hg-S-C), 1 oxidation and two reductions. → 3 is photochromic (t1/2,relaxation = 1300 s). → Electrochemistry of ground and photo-activated 3 is identical. → Spectroelectrochemistry of 3 highlights electrochromism. - Abstract: The reactions between dithizone (H2Dz, (1)) or potassium dithizonate (K+HDz-, (2)) and phenylmercury(II) chloride gives PhHg(HDz), (3). Complex (3) is photochromic. In dichloromethane, the blue photo-exited state of (3) exhibits a first order relaxation process to regenerate the orange ground state with rate constant 0.00053 s-1. The half life of this relaxation is ca. 1300 s. Electrochemically, on cyclic voltammetry time scale, the oxidations of (1) and (3) are different. A comparative voltammetric and spectro-electrochemical study of (1) and (3) in CH2Cl2 containing 0.1 mol dm-3 [N(nBu)4][B(C6F5)4] revealed that the mercapto group of (1) can be oxidised in two one-electron transfer steps. A disulphide is first produced and then in a second oxidation step, HDz+ is formed. In contrast, complex (3) shows only one ligand-based oxidation step. Upon complexation with phenylmercury the free mercaptan group of (1) becomes a stable 'metal thioether', Hg-S-C, which effectively prevents disulphide formation in (3) upon electrochemical oxidation. Both (1) and (3) shows two reduction steps. The electrochemical fingerprint of blue photo-excited (3) is identical to that of the orange ground state as no new functional groups are introduced upon irradiation; only bond rotation occurs. The different electronic spectra for each of the redox states of (3), obtained from spectro-electrochemical measurements, revealed that only the (3)/(3-) couple exhibits electrochromic properties.

  12. Electrochemistry of molecules with two (or more) redox centers

    Czech Academy of Sciences Publication Activity Database

    Ludvík, Jiří

    Lisboa : Instituto Superior de Engenharia de Lisboa, 2010. s. 16. [Iberian Meeting of Electrochemistry /12./ & Meeting of the Portuguese Electrochemical Society /16./. 08.09.2010-11.09.2010, Lisboa] R&D Projects: GA AV ČR IAA400400813; GA MŠk ME09002 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * molecules Subject RIV: CG - Electrochemistry

  13. An Audio-Tutorial Approach to the Teaching of Physical Chemistry and Electrochemistry.

    Science.gov (United States)

    Lower, Stephen K.

    1981-01-01

    Demonstrates how audiotutorial techniques can be applied to the teaching of more advanced subjects (physical chemistry and electrochemistry), and how this can have significant affect on the overall quality of instruction and the mechanics of teaching the course. Includes a general description of audiotutorial instruction. (SK)

  14. 7. International Frumkin Symposium. Basic electrochemistry for science and technology. Abstracts. Part 1

    International Nuclear Information System (INIS)

    Modern tendencies of development of electrochemistry as in regions of fundamental investigations so in applied directions are presented. Basic themes of reports presented are: charge transport in condensed media, interface fenomena and electric properties at low soluble substances with electrolyte solutions, structure and properties of charged interfaces, transport in electrochemical systems, problems of bioelectrochemistry

  15. Electrochemistry and spectro-electrochemistry of dithizonatophenylmercury(II)

    Energy Technology Data Exchange (ETDEWEB)

    Eschwege, Karel G. von; As, Lydia van [Department of Chemistry, University of the Free State, Bloemfontein 9300 (South Africa); Swarts, Jannie C., E-mail: swartsjc@ufs.ac.za [Department of Chemistry, University of the Free State, Bloemfontein 9300 (South Africa)

    2011-11-30

    Graphical abstract: Display Omitted Highlights: > CV and spectroelectrochemistry of dithizone and PhHgHDz, 3, is presented. > CV shows 3 has stable metal thioether (Hg-S-C), 1 oxidation and two reductions. > 3 is photochromic (t{sub 1/2,} {sub relaxation} = 1300 s). > Electrochemistry of ground and photo-activated 3 is identical. > Spectroelectrochemistry of 3 highlights electrochromism. - Abstract: The reactions between dithizone (H{sub 2}Dz, (1)) or potassium dithizonate (K{sup +}HDz{sup -}, (2)) and phenylmercury(II) chloride gives PhHg(HDz), (3). Complex (3) is photochromic. In dichloromethane, the blue photo-exited state of (3) exhibits a first order relaxation process to regenerate the orange ground state with rate constant 0.00053 s{sup -1}. The half life of this relaxation is ca. 1300 s. Electrochemically, on cyclic voltammetry time scale, the oxidations of (1) and (3) are different. A comparative voltammetric and spectro-electrochemical study of (1) and (3) in CH{sub 2}Cl{sub 2} containing 0.1 mol dm{sup -3} [N({sup n}Bu){sub 4}][B(C{sub 6}F{sub 5}){sub 4}] revealed that the mercapto group of (1) can be oxidised in two one-electron transfer steps. A disulphide is first produced and then in a second oxidation step, HDz{sup +} is formed. In contrast, complex (3) shows only one ligand-based oxidation step. Upon complexation with phenylmercury the free mercaptan group of (1) becomes a stable 'metal thioether', Hg-S-C, which effectively prevents disulphide formation in (3) upon electrochemical oxidation. Both (1) and (3) shows two reduction steps. The electrochemical fingerprint of blue photo-excited (3) is identical to that of the orange ground state as no new functional groups are introduced upon irradiation; only bond rotation occurs. The different electronic spectra for each of the redox states of (3), obtained from spectro-electrochemical measurements, revealed that only the (3)/(3{sup -}) couple exhibits electrochromic properties.

  16. A Tape-Lecture Course in Electrochemistry.

    Science.gov (United States)

    Sheridan, P.

    1978-01-01

    Investigates the possibility of using audio-tapes for self-study courses in technical colleges. This article presents: (1) description of the electrochemistry course taught; (2) results of the assessment of student reaction to the course; and (3) conclusions. (HM)

  17. Electrochemistry in the General Chemistry Curriculum.

    Science.gov (United States)

    Chambers, James Q.

    1983-01-01

    Outlines several ideas on introductory electrochemistry material suitable for college-level general chemistry. These include discussions of conductivity in solids and electrolytes, electrical quantities/properties, electrode potentials, and membrane potentials. Indicates that whatever strategy is used to present this material, the presentation…

  18. Electrochemistry in Supercritical Fluids: A Mini Review

    OpenAIRE

    Toghill, Kathryn E.; Mendez, Manuel A.; Voyame, Patrick

    2014-01-01

    A brief overview of the literature relating to electrochemical studies and processes undertaken in supercritical fluids is presented. This review mostly concerns carbon dioxide and hydrofluorocarbons, given the accessibility of their supercritical states, and does not consider the emerging body of research in expanded phase electrochemistry.

  19. Bipolar electrochemistry for high throughput screening applications

    OpenAIRE

    Munktell, Sara

    2016-01-01

    Bipolar electrochemistry is an interesting concept for high throughput screening techniques due to the ability to induce gradients in a range of materials and their properties, such as composition, particle size, or dopant levels, among many others. One of the key advantages of the method is the ability to test, create or modify materials without the need for a direct electrical connection. In this thesis, the viability of this method has been explored for a range of possible applications, su...

  20. Computational electrochemistry: From small molecules to metalloproteins

    Czech Academy of Sciences Publication Activity Database

    Srnec, Martin; Kývala, Mojmír; Bím, Daniel; Ryde, U.; Rulíšek, Lubomír

    Praha: MATFYZPRESS, 2015 - (Burda, J.). s. 71 ISBN 978-80-7378-303-7. [Modeling Interactions in Biomolecules /7./. 14.09.2015-18.09.2015, Praha] R&D Projects: GA ČR(CZ) GA14-31419S; GA ČR(CZ) GJ15-10279Y Institutional support: RVO:61388963 ; RVO:61388955 Keywords : computational electrochemistry * metalloprotein structure * physico-chemical properties Subject RIV: CF - Physical ; Theoretical Chemistry

  1. Electrochemistry of Potential Eu MRI Complexes

    Czech Academy of Sciences Publication Activity Database

    Gál, Miroslav; Sokolová, Romana; Kielar, P.

    Ústí nad Labem : BEST servis, 2012 - (Navrátil, T.; Fojta, M.), s. 38-41 ISBN 978-80-905221-0-7. [Moderní elektrochemické metody /32./. Jetřichovice (CZ), 21.05.2012-25.05.2012] R&D Projects: GA ČR GA203/09/1607 Institutional support: RVO:61388955 Keywords : contrast agent * MRI * cyclic voltammetry Subject RIV: CG - Electrochemistry

  2. Annals of the 4. Brazilian Symposium on Electrochemistry and Electroanalytics

    International Nuclear Information System (INIS)

    Theoretical and experimental papers on electrochemistry and electroanalysis are presented. The techniques used are: voltametry, polarography, ellipsometry, coulometric titration, luminescence, potentiometry, electrodeposition and photoelectrochemistry. (C.L.B.)

  3. Development of a 3-electrode system for gas phase dynamic electrochemistry

    OpenAIRE

    Fowowe, T.

    2011-01-01

    The principles of potentiometry from liquid phase electrochemistry have already been applied to the gas phase by considering a flame as an ionised gaseous environment which can behave as a dilute electrolyte. This study focused on the design, construction and optimisation of a 3-electrode electrochemical cell for direct electron transfer in the gas phase. Three electrochemical cells were developed with the final design deemed satisfactory to conduct electrochemical measureme...

  4. Electrochemistry and Spectroelectrochemistry of Bioactive Hydroxyquinolines: A Mechanistic Study

    Czech Academy of Sciences Publication Activity Database

    Sokolová, Romana; Nycz, J. E.; Ramešová, Šárka; Fiedler, Jan; Degano, I.; Szala, M.; Kolivoška, Viliam; Gál, M.

    2015-01-01

    Roč. 119, č. 20 (2015), s. 6074-6080. ISSN 1520-6106 Grant ostatní: Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR M200401201 Institutional support: RVO:61388955 Keywords : electrochemistry * spectroelectrochemistry * Bioactive Hydroxyquinolines Subject RIV: CG - Electrochemistry Impact factor: 3.302, year: 2014

  5. Application and Utilization of Electrochemistry in Organic Chemistry

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Tomáš

    2011-01-01

    Roč. 15, č. 17 (2011), s. 2921-2922. ISSN 1385-2728 R&D Projects: GA AV ČR IAA400400806 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * organic chemistry * applications Subject RIV: CG - Electrochemistry Impact factor: 3.064, year: 2011

  6. Carbon Nanotube Electrodes for Hot-Wire Electrochemistry

    Czech Academy of Sciences Publication Activity Database

    Gründler, P.; Frank, Otakar; Kavan, Ladislav; Dunsch, L.

    2009-01-01

    Roč. 10, č. 3 (2009), s. 559-563. ISSN 1439-4235 R&D Projects: GA AV ČR IAA400400804; GA AV ČR KAN200100801 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * electrodes * nanotubes * Raman spectroscopy Subject RIV: CG - Electrochemistry Impact factor: 3.453, year: 2009

  7. Development of an Electrochemistry Teaching Sequence Using a Phenomenographic Approach

    Science.gov (United States)

    Rodriguez-Velazquez, Sorangel

    2013-01-01

    Electrochemistry is the area of chemistry that studies electron transfer reactions across an interface. Chemistry education researchers have acknowledged that difficulties in electrochemistry instruction arise due to the level of abstraction of the topic, lack of adequate explanations and representations found in textbooks, and a quantitative…

  8. Electrochemistry as a Tool for an Enzyme Characterization

    Czech Academy of Sciences Publication Activity Database

    Gál, M.; Krahulec, J.; Jiríčková, K.; Sokolová, Romana; Híveš, J.

    Ústí nad Labem: Best Servis, 2014 - (Navrátil, T.; Fojta, M.; Pecková, K.), s. 40-43 ISBN 978-80-905221-2-1. [Moderní Elektrochemické Metody /34./. Jetřichovice (CZ), 19.05.2014-23.05.2014] Institutional support: RVO:61388955 Keywords : electrochemistry * Enterokinase * Impedance spectroscopy Subject RIV: CG - Electrochemistry

  9. NASA Glenn Research Center Electrochemistry Branch Overview

    Science.gov (United States)

    Manzo, Michelle A.; Hoberecht, Mark; Reid, Concha

    2010-01-01

    This presentation covers an overview of NASA Glenn's history and heritage in the development of electrochemical systems for aerospace applications. Current programs related to batteries and fuel cells are addressed. Specific areas of focus are Li-ion batteries and Polymer Electrolyte Membrane Fuel cells systems and their development for future Exploration missions. The presentation covers details of current component development efforts for high energy and ultra high energy Li-ion batteries and non-flow-through fuel cell stack and balance of plant development. Electrochemistry Branch capabilities and facilities are also addressed.

  10. Electrochemistry of selected radiosenzitizer-etanidazole

    Czech Academy of Sciences Publication Activity Database

    Gál, Miroslav; Híveš, J.; Sokolová, Romana; Hromadová, Magdaléna; Kocábová, Jana; Kolivoška, Viliam; Pospíšil, Lubomír

    Ústí nad Labem: BEST servis, 2010 - (Navrátil, T.; Barek, J.), s. 55-59 ISBN 978-80-254-6710-7. [Modern Electroanalytical Methods /30./. Jetřichovice (CZ), 24.05.2010-28.05.2010] R&D Projects: GA ČR GP203/09/P502; GA MŠk LC510; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40400503 Keywords : etanidazole * cyclic voltammetry * radiosensitizers * electrochemical impendance spectroscopy Subject RIV: CG - Electrochemistry

  11. Ultra-micro-electrochemistry under irradiation

    International Nuclear Information System (INIS)

    In this work, are exposed volt-amperometric results recorded in situ during irradiation by electrons, protons or helium ions of homogeneous solutions and solid/deionized water interfaces where the solid can be: quartz, steel or uranium oxide. In a second part, the electrochemical answer is obtained in approaching the ultra-micro-electrode in close vicinity to the solid, at a distance inferior to those corresponding to the diffusion layer of this last ones. The last part deals with the results of an experiment which is until now unique: the in situ coupling of ultra-micro-electrochemistry with Raman micro-spectrometry in order to follow the UO2 corrosion during its irradiation by He2+ particles. (O.M.)

  12. Corrosive electrochemistry of jamesonite by cyclic voltammetry

    Institute of Scientific and Technical Information of China (English)

    余润兰; 胡岳华; 邱冠周; 覃文庆

    2004-01-01

    The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the strong adsorption of oxidation elemental sulfur on jamesonite. A deficient-metal and sulfur-rich compound is formed under the potential of 80 mV at pH 6.86. The passive action by elemental sulfur occurs from 80 to 470 mV and S2O23- , SO24- are produced at potential over 470 mV. The anodic peak producing SO24- is inhibited due to the deposition of PbSO4 at higher potential in Na2SO4 solution. The corrosive action of jamesonite becomes strong and the redox characterization similar to PbS, FeS and Sb2 S3 appears at pH 9.18.

  13. Electrochemistry-based Battery Modeling for Prognostics

    Science.gov (United States)

    Daigle, Matthew J.; Kulkarni, Chetan Shrikant

    2013-01-01

    Batteries are used in a wide variety of applications. In recent years, they have become popular as a source of power for electric vehicles such as cars, unmanned aerial vehicles, and commericial passenger aircraft. In such application domains, it becomes crucial to both monitor battery health and performance and to predict end of discharge (EOD) and end of useful life (EOL) events. To implement such technologies, it is crucial to understand how batteries work and to capture that knowledge in the form of models that can be used by monitoring, diagnosis, and prognosis algorithms. In this work, we develop electrochemistry-based models of lithium-ion batteries that capture the significant electrochemical processes, are computationally efficient, capture the effects of aging, and are of suitable accuracy for reliable EOD prediction in a variety of usage profiles. This paper reports on the progress of such a model, with results demonstrating the model validity and accurate EOD predictions.

  14. Electrochemistry of Flavonolignans in Acetonitrile and Dimethylsulfoxide

    Czech Academy of Sciences Publication Activity Database

    Sokolová, Romana; Kocábová, Jana; Fiedler, Jan; Vacek, J.; Marhol, Petr; Vavříková, Eva; Křen, Vladimír

    Ústí nad Labem : Best Servis, 2014 - (Navrátil, T.; Fojta, M.; Pecková, K.), s. 161-165 ISBN 978-80-905221-2-1. [Moderní Elektrochemické Metody /34./. Jetřichovice (CZ), 19.05.2014-23.05.2014] R&D Projects: GA ČR(CZ) GAP207/11/0629 Grant ostatní: Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR M200401201 Institutional support: RVO:61388955 ; RVO:61388971 Keywords : Silybin * 2,3-Dehydrosilybin * Electron transfer Subject RIV: CG - Electrochemistry ; CE - Biochemistry (MBU-M)

  15. Graphene and its electrochemistry - an update.

    Science.gov (United States)

    Ambrosi, Adriano; Chua, Chun Kiang; Latiff, Naziah Mohamad; Loo, Adeline Huiling; Wong, Colin Hong An; Eng, Alex Yong Sheng; Bonanni, Alessandra; Pumera, Martin

    2016-05-01

    The electrochemistry of graphene and its derivatives has been extensively researched in recent years. In the aspect of graphene preparation methods, the efficiencies of the top-down electrochemical exfoliation of graphite, the electrochemical reduction of graphene oxide and the electrochemical delamination of CVD grown graphene, are currently on par with conventional procedures. Electrochemical analysis of graphene oxide has revealed an unexpected inherent redox activity with, in some cases, an astonishing chemical reversibility. Furthermore, graphene modified with p-block elements has shown impressive electrocatalytic performances in processes which have been historically dominated by metal-based catalysts. Further progress has also been achieved in the practical usage of graphene in sensing and biosensing applications. This review is an update of our previous article in Chem. Soc. Rev. 2010, 39, 4146-4157, with special focus on the developments over the past two years. PMID:27052352

  16. Analytical Electrochemistry: Methodology and Applications of Dynamic Techniques.

    Science.gov (United States)

    Heineman, William R.; Kissinger, Peter T.

    1980-01-01

    Reports developments involving the experimental aspects of finite and current analytical electrochemistry including electrode materials (97 cited references), hydrodynamic techniques (56), spectroelectrochemistry (62), stripping voltammetry (70), voltammetric techniques (27), polarographic techniques (59), and miscellany (12). (CS)

  17. Analytical Electrochemistry: Theory and Instrumentation of Dynamic Techniques.

    Science.gov (United States)

    Johnson, Dennis C.

    1980-01-01

    Emphasizes trends in the development of six topics concerning analytical electrochemistry, including books and reviews (34 references cited), mass transfer (59), charge transfer (25), surface effects (33), homogeneous reactions (21), and instrumentation (31). (CS)

  18. Electrochemistry of proteins and nucleic acids. Tools for biomedicine

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Ostatná, Veronika; Masařík, Michal; Dorčák, Vlastimil; Trefulka, Mojmír; Havran, Luděk; Fojta, Miroslav

    Benediktbeuern, 2006. s. 1-1. [10th International Fischer Symposium. 23.07.2006-26.07.2006, Benediktbeuern] Institutional research plan: CEZ:AV0Z50040507 Keywords : electrochemistry of DNA * electroactivity of proteins Subject RIV: BO - Biophysics

  19. Proceedings of the ISEAC international symposium cum workshop on electrochemistry

    International Nuclear Information System (INIS)

    This symposium highlights the role of chemistry to find out the solution of some global problems. Among the leading branches of chemistry, the foot prints of electrochemistry can be seen in a variety of fields for both fundamental studies and methodological applications. Electrochemistry and allied science has already exhibited its potential to meet the world's need starting from health and medicine, environment, nanofabrication to alternate energy resources. Articles relevant to INIS are indexed separately

  20. Tungsten Oxides for Photocatalysis, Electrochemistry, and Phototherapy.

    Science.gov (United States)

    Huang, Zhen-Feng; Song, Jiajia; Pan, Lun; Zhang, Xiangwen; Wang, Li; Zou, Ji-Jun

    2015-09-23

    The conversion, storage, and utilization of renewable energy have all become more important than ever before as a response to ever-growing energy and environment concerns. The performance of energy-related technologies strongly relies on the structure and property of the material used. The earth-abundant family of tungsten oxides (WOx ≤3 ) receives considerable attention in photocatalysis, electrochemistry, and phototherapy due to their highly tunable structures and unique physicochemical properties. Great breakthroughs have been made in enhancing the optical absorption, charge separation, redox capability, and electrical conductivity of WOx ≤3 through control of the composition, crystal structure, morphology, and construction of composite structures with other materials, which significantly promotes the efficiency of processes and devices based on this material. Herein, the properties and synthesis of WOx ≤3 family are reviewed, and then their energy-related applications are highlighted, including solar-light-driven water splitting, CO2 reduction, and pollutant removal, electrochromism, supercapacitors, lithium batteries, solar and fuel cells, non-volatile memory devices, gas sensors, and cancer therapy, from the aspect of function-oriented structure design and control. PMID:26287959

  1. Pyrolytic 3D Carbon Microelectrodes for Electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Amato, Letizia;

    2016-01-01

    coated, SB at 50C for 6h and UV exposed (E2 – 149mJ cm-2) (figure 1.A.b). A second partial exposure E3 – 28mJ cm-2 is performed to obtain a suspended layer followed by a PEB at 50C for 8h (figure 1.A.c). The partial exposure dose at wavelength 365nm and the low temperature (50C) baking steps plays...... be fabricated (figure 1.B). Figure 1.C shows the electrochemical characterization of a three electrodes system, comparing planar and 3D carbon working electrodes. The cyclic voltammograms performed in 10mM ferri-ferrocyanide show higher peak current (2 folds higher) for the 3D microelectrodes compared to the 2D...... ones (figure 1.C). The 3D microelectrodes potentially increase the overall sensitivity in amperometric monitoring of cell response due to the increase surface area and enhanced interaction with cells [3]. Reference: [1] R. L. McCreery, “Advanced carbon electrode materials for molecular electrochemistry...

  2. ELECTROCHEMISTRY OF FISCHER AMINOCARBENE COMPLEXES: EFFECTS OF STRUCTURE ON REDOX PROPERTIES, ELECTRON DISTRIBUTION, AND REACTION MECHANISMS

    Czech Academy of Sciences Publication Activity Database

    Ludvík, Jiří; Hoskovcová, I.

    Hoboken : Wiley, 2014 - (Pombeiro, A.), s. 653-665 ISBN 978-1-118-51014-8 Institutional support: RVO:61388955 Keywords : electrochemistry * Fischer Aminocarbene Complexes * Redox Properties Subject RIV: CG - Electrochemistry

  3. Water as a Promoter and Catalyst for Dioxygen Electrochemistry in Aqueous and Organic Media

    Czech Academy of Sciences Publication Activity Database

    Staszak-Jirkovský, J.; Subbaraman, R.; Strmcnik, D.; Harrison, K. L.; Diesendruck, Ch. E.; Assary, R.; Frank, Otakar; Kobr, L.; Wiberg, G. K. H.; Genorio, B.; Connell, J. G.; Lopes, P. P.; Stamenkovic, V. R.; Curtiss, L.; Moore, J. S.; Zavadil, K. R.; Markovic, N. M.

    2015-01-01

    Roč. 5, č. 11 (2015), s. 6600-6607. ISSN 2155-5435 Institutional support: RVO:61388955 Keywords : electrochemistry * electrocatalysis * binding energy Subject RIV: CG - Electrochemistry Impact factor: 9.312, year: 2014

  4. Bimetallic alloys in action: dynamic atomistic motifs for electrochemistry and catalysis

    Czech Academy of Sciences Publication Activity Database

    Mueller, J. E.; Krtil, Petr; Kubler, L. A.; Jacob, T.

    2014-01-01

    Roč. 16, č. 29 (2014), s. 15029-15042. ISSN 1463-9076 Institutional support: RVO:61388955 Keywords : Bimetallic alloys * electrochemistry * catalysis Subject RIV: CG - Electrochemistry Impact factor: 4.493, year: 2014

  5. Conceptual Difficulties of Secondary School Students in Electrochemistry

    Directory of Open Access Journals (Sweden)

    Muzammila Akram

    2014-09-01

    Full Text Available This study designed primarily to explore conceptual difficulties of secondary school students to understand the basic features of the concept of electrochemistry like redox reactions, galvanic and electrolytic cells. Furthermore, the factors that cause the conceptual difficulties of secondary school students in electrochemistry also investigated. Mixed method research design adopted to achieve the objectives of the current study. Three (3 government secondary schools selected by using the cluster random sampling technique within Bahawalpur City of Pakistan. Then 144 chemistry students of IX class purposively selected as sample of the study. Conceptual difficulties of secondary school students in electrochemistry investigated by developing a special test instrument tagged as Test designed to measure the Conceptual Difficulties in Electrochemistry (TCDE. Eminent experts of chemistry education validated TCDE. A pilot test established to find its reliability by test re-tests method and the correlation coefficient (r was 0.96. The Cronbach alpha coefficient also calculated to measure the internal consistency of instrument through SPSS, and its value was 0.87. Thirty students selected purposively based on the result of TCDE for semi-structured interview. The result showed that 67% of the concept-based items designed in electrochemistry were difficult to understand by secondary school students. Poor background of knowledge, absence of teaching aids, and misunderstanding of language caused conceptual difficulty in comprehension. The findings suggested some recommendations to expedite better understanding of the chemistry students.

  6. Iron(0) Aminocarbene Complexes Bearing Heterocyclic Substituent on Carbene Carbon Atom: Electrochemistry and Reactivity

    Czech Academy of Sciences Publication Activity Database

    Hoskovcová, I.; Zvěřinová, R.; Dvořák, D.; Záliš, Stanislav; Ludvík, Jiří

    Lausanne: International Society of Electrochemistry, 2008, 080898-080898. [Annual Meeting of the International Society of Electrochemistry /59./. Seville (ES), 07.09.2008-12.09.2008] R&D Projects: GA AV ČR IAA400400813 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * reactivity * iron aminocarbene complexes Subject RIV: CG - Electrochemistry http://www.uco.es/electroquimica-rseq/Circular_Seville08.pdf

  7. Developments in electrochemistry science inspired by Martin Fleischmann

    CERN Document Server

    Pletcher, Derek; Williams, David

    2014-01-01

    Martin Fleischmann was truly one of the 'fathers' of modern electrochemistry having made major contributions to diverse topics within electrochemical science and technology. These include the theory and practice of voltammetry and in situ spectroscopic techniques, instrumentation, electrochemical phase formation, corrosion, electrochemical engineering, electrosynthesis and cold fusion.  While intended to honour the memory of Martin Fleischmann, Developments in Electrochemistry is neither a biography nor a history of his contributions. Rather, the book is a series of critical reviews of topic

  8. Understanding Electrochemistry Concepts Using the Predict-Observe-Explain Strategy

    Science.gov (United States)

    Karamustafaoglu, Sevilay; Mamlok-Naaman, Rachel

    2015-01-01

    The current study deals with freshman students who study at the Department of Science at the Faculty of Education. The aim of the study was to investigate the effect of teaching electrochemistry concepts using Predict-Observe-Explain (POE) strategy. The study was quasi-experimental design using 20 students each in the experimental group (EG) and…

  9. Using a Teaching Model To Correct Known Misconceptions in Electrochemistry.

    Science.gov (United States)

    Huddle, Penelope Ann; White, Margaret Dawn; Rogers, Fiona

    2000-01-01

    Describes a concrete teaching model designed to eliminate students' misconceptions about current flow in electrochemistry. The model uses a semi-permeable membrane rather than a salt bridge to complete the circuit and demonstrate the maintenance of cell neutrality. Concludes that use of the model led to improvement in students' understanding at…

  10. Facilitating Conceptual Change in Students' Understanding of Electrochemistry.

    Science.gov (United States)

    Niaz, Mansoor

    2002-01-01

    Constructs a teaching strategy to facilitate conceptual change in freshman students' understanding of electrochemistry. Provides students with the correct response along with alternative responses (teaching experiments), producing a conflicting situation that is conducive to an equilibration of their cognitive structures. Concludes that the…

  11. Alleviating the Common Confusion Caused by Polarity in Electrochemistry.

    Science.gov (United States)

    Moran, P. J.; Gileadi, E.

    1989-01-01

    Discussed is some of the confusion encountered in electrochemistry due to misunderstandings of sign conventions and simple mathematical errors. Clarified are issues involving emf series, IUPAC sign conventions, calculation of cell potentials, reference electrodes, the polarity of electrodes in electrochemical devices, and overpotential. (CW)

  12. (The latest developments of the physical aspects of electrochemistry)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, S.H.

    1990-09-24

    The author was one of 26 invited lecturers to discuss the latest developments of the physical aspects of electrochemistry. He interacted extensively with other lecturers and many participants from developing countries. He also visited with the Director of the Italian Synchrotron Radiation Source now under construction in Trieste, Italy.

  13. Application of ultrasound in electrochemistry - design of experimental arrangement

    Czech Academy of Sciences Publication Activity Database

    Klíma, Jiří

    Krakow: Department of Chemistry and Technology of Polymers, Krakow University of Technology , 2009, s. 43-44. ISBN 978-83-928784-0-7. [COST Action D32 Final Meeting "Chemistry in high-energy microenvironments". Krakow (PL), 30.03.2009-30.03.2009] Institutional research plan: CEZ:AV0Z40400503 Keywords : sonoelectrochemistry * sonication * sonochemistry Subject RIV: CG - Electrochemistry

  14. Common Student Misconceptions in Electrochemistry: Galvanic, Electrolytic, and Concentration Cells.

    Science.gov (United States)

    Sanger, Michael J.; Greenbowe, Thomas J.

    1997-01-01

    Investigates student (N=16) misconceptions concerning electrochemistry related to galvanic, electrolytic, and concentration cells. Findings indicate that most students demonstrating misconceptions were still able to calculate cell potentials correctly. Discusses common misconceptions and possible sources of these. Contains 33 references.…

  15. Au-Biocompatible metallic nanostructures in metalloprotein electrochemistry and electrocatalysis

    DEFF Research Database (Denmark)

    Jensen, Palle Skovhus; Engelbrekt, Christian; Sørensen, Karsten Holm;

    2012-01-01

    Molecular scale metallic nanoparticles coated by molecular monolayers and immobilized on single-crystal Au-electrode surfaces are efficient catalysts in metalloprotein voltammetry. Nanoparticles prepared by a new ‘‘green’’ method also exhibit strong electrocatalysis in both protein electrochemistry...

  16. Electrochemical Preparation of Oxide Materials for Electrochemistry and Electronics

    Czech Academy of Sciences Publication Activity Database

    Krtil, Petr; Yoshimura, M.

    1998-01-01

    Roč. 2, - (1998), s. 321-327. ISSN 1432-8488 Grant ostatní: Research for the Future(JP) 96R06901 Keywords : soft solution processing * EQCM * alkali earth metal tungstates Subject RIV: CG - Electrochemistry Impact factor: 1.097, year: 1998

  17. Corrosion of structural materials and electrochemistry in high temperature water of nuclear power systems

    International Nuclear Information System (INIS)

    The latest experiences with corrosion in the cooling systems of nuclear power plants are reviewed. High temperature cooling water causes corrosion of structural materials, which often leads to adverse effects in the plants, e.g., generating defects in materials of major components and fuel claddings, increasing shutdown radiation and increasing the volume of radwaste sources. Corrosion behaviors are much affected by water qualities and differ according to the values of water qualities and the materials themselves. In order to establish reliable operation, each plant requires its own unique optimal water chemistry control based on careful consideration of its system, materials and operational history. Electrochemistry is one of key issues that determine corrosion related problems but it is not the only issue. Most phenomena for corrosion related problems, e.g., flow-accelerated corrosion (FAC), intergranular stress corrosion cracking (IGSCC), primary water stress corrosion cracking (PWSCC) and thinning of fuel cladding materials, can be understood based on an electrochemical index, e.g., electrochemical corrosion potential (ECP), conductivities and pH. The most important electrochemical index, ECP, can be measured at elevated temperature and applied to in situ sensors of corrosion conditions to detect anomalous conditions of structural materials at their very early stages. In the paper, theoretical models based on electrochemistry to estimate wall thinning rate of carbon steel piping due to flow-accelerated corrosion and corrosive conditions determining IGSCC crack initiation and growth rate are introduced. (author)

  18. Scanning thermo-ionic microscopy for probing local electrochemistry at the nanoscale

    Science.gov (United States)

    Eshghinejad, Ahmadreza; Nasr Esfahani, Ehsan; Wang, Peiqi; Xie, Shuhong; Geary, Timothy C.; Adler, Stuart B.; Li, Jiangyu

    2016-05-01

    Conventional electrochemical characterization techniques based on voltage and current measurements only probe faradaic and capacitive rates in aggregate. In this work we develop a scanning thermo-ionic microscopy (STIM) to probe local electrochemistry at the nanoscale, based on imaging of Vegard strain induced by thermal oscillation. It is demonstrated from both theoretical analysis and experimental validation that the second harmonic response of thermally induced cantilever vibration, associated with thermal expansion, is present in all solids, whereas the fourth harmonic response, caused by local transport of mobile species, is only present in ionic materials. The origin of STIM response is further confirmed by its reduced amplitude with respect to increased contact force, due to the coupling of stress to concentration of ionic species and/or electronic defects. The technique has been applied to probe Sm-doped Ceria and LiFePO4, both of which exhibit higher concentrations of mobile species near grain boundaries. The STIM gives us a powerful method to study local electrochemistry with high sensitivity and spatial resolution for a wide range of ionic systems, as well as ability to map local thermomechanical response.

  19. Strain Engineering to Modify the Electrochemistry of Energy Storage Electrodes

    Science.gov (United States)

    Muralidharan, Nitin; Carter, Rachel; Oakes, Landon; Cohn, Adam P.; Pint, Cary L.

    2016-01-01

    Strain engineering has been a critical aspect of device design in semiconductor manufacturing for the past decade, but remains relatively unexplored for other applications, such as energy storage. Using mechanical strain as an input parameter to modulate electrochemical potentials of metal oxides opens new opportunities intersecting fields of electrochemistry and mechanics. Here we demonstrate that less than 0.1% strain on a Ni-Ti-O based metal-oxide formed on superelastic shape memory NiTi alloys leads to anodic and cathodic peak potential shifts by up to ~30 mV in an electrochemical cell. Moreover, using the superelastic properties of NiTi to enable strain recovery also recovers the electrochemical potential of the metal oxide, providing mechanistic evidence of strain-modified electrochemistry. These results indicate that mechanical energy can be coupled with electrochemical systems to efficiently design and optimize a new class of strain-modulated energy storage materials. PMID:27283872

  20. Strain Engineering to Modify the Electrochemistry of Energy Storage Electrodes

    Science.gov (United States)

    Muralidharan, Nitin; Carter, Rachel; Oakes, Landon; Cohn, Adam P.; Pint, Cary L.

    2016-06-01

    Strain engineering has been a critical aspect of device design in semiconductor manufacturing for the past decade, but remains relatively unexplored for other applications, such as energy storage. Using mechanical strain as an input parameter to modulate electrochemical potentials of metal oxides opens new opportunities intersecting fields of electrochemistry and mechanics. Here we demonstrate that less than 0.1% strain on a Ni-Ti-O based metal-oxide formed on superelastic shape memory NiTi alloys leads to anodic and cathodic peak potential shifts by up to ~30 mV in an electrochemical cell. Moreover, using the superelastic properties of NiTi to enable strain recovery also recovers the electrochemical potential of the metal oxide, providing mechanistic evidence of strain-modified electrochemistry. These results indicate that mechanical energy can be coupled with electrochemical systems to efficiently design and optimize a new class of strain-modulated energy storage materials.

  1. Electrochemistry of bile acids, cholesterol, and related compounds (an overview)

    OpenAIRE

    Pecková, Karolina; Nesměrák, Karel

    2012-01-01

    This review summarizes electrochemical methods used for the investigation, determination, and monitoring of bile acids and their conjugates, cholesterol, phytosterols, and related compounds. In electrochemistry-related research they do not belong among frequently studied compounds, because they are inactive under variety of conditions and electrode materials. The several examples of their redox activity include electrochemical reduction of bile acids at mercury electrodes and modified glassy ...

  2. Electrochemistry of Flavonolignans and their Interactions with DNA and Proteins

    Czech Academy of Sciences Publication Activity Database

    Pyszková, M.; Zatloukalová, M.; Biedermann, David; Křen, Vladimír; Ulrichová, J.; Ramešová, Šárka; Sokolová, Romana; Vacek, J.

    Ústí nad Labem : Best Servis, 2014 - (Navrátil, T.; Fojta, M.; Pecková, K.), s. 148-152 ISBN 978-80-905221-2-1. [Moderní Elektrochemické Metody /34./. Jetřichovice (CZ), 19.05.2014-23.05.2014] Institutional support: RVO:61388955 ; RVO:61388971 Keywords : Flavonolignan * Silymarin * Oxidation Subject RIV: CG - Electrochemistry; CE - Biochemistry (MBU-M)

  3. Synthesis, Electrochemistry, and Photophysics of Aza-BODIPY Porphyrin Dyes.

    Science.gov (United States)

    Pascal, Simon; Bucher, Léo; Desbois, Nicolas; Bucher, Christophe; Andraud, Chantal; Gros, Claude P

    2016-03-24

    The synthesis of dyad and triad aza-BODIPY-porphyrin systems in two steps starting from an aryl-substituted aza-BODIPY chromophore is described. The properties of the resulting aza-BODIPY-porphyrin conjugates have been extensively investigated by means of electrochemistry, spectroelectrochemistry, and absorption/emission spectroscopy. Fluorescence measurements have revealed a dramatic loss of luminescence intensity, mainly due to competitive energy transfer and photoinduced electron transfer involving charge separation followed by recombination. PMID:26938146

  4. Development of an Electrochemistry Teaching Sequence using a Phenomenographic Approach

    Science.gov (United States)

    Rodriguez-Velazquez, Sorangel

    Electrochemistry is the area of chemistry that studies electron transfer reactions across an interface. Chemistry education researchers have acknowledged that difficulties in electrochemistry instruction arise due to the level of abstraction of the topic, lack of adequate explanations and representations found in textbooks, and a quantitative emphasis in the application of concepts. Studies have identified conceptions (also referred to as misconceptions, alternative conceptions, etc.) about the electrochemical process that transcends academic and preparation levels (e.g., students and instructors) as well as cultural and educational settings. Furthermore, conceptual understanding of the electrochemical process requires comprehension of concepts usually studied in physics such as electric current, resistance and potential and often neglected in introductory chemistry courses. The lack of understanding of physical concepts leads to students. conceptions with regards to the relation between the concepts of redox reactions and electric circuits. The need for instructional materials to promote conceptual understanding of the electrochemical process motivated the development of the electrochemistry teaching sequence presented in this dissertation. Teaching sequences are educational tools that aim to bridge the gap between student conceptions and the scientific acceptable conceptions that instructors expect students to learn. This teaching sequence explicitly addresses known conceptions in electrochemistry and departs from traditional instruction in electrochemistry to reinforce students. previous knowledge in thermodynamics providing the foundation for the explicit relation of redox reactions and electric circuits during electrochemistry instruction. The scientific foundations of the electrochemical process are explained based on the Gibbs free energy (G) involved rather than on the standard redox potential values (E° ox/red) of redox half-reactions. Representations of

  5. Boron Doped Diamond Electrode: Spectro/Photo/Electrochemistry and Prospective Application in Dye-Sensitized Solar Cell

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Vlčková Živcová, Zuzana; Krýsová, Hana; Petrák, Václav; Bartoň, Jan; Cígler, Petr; Nesládek, M.

    Angra dos Reis: International Society of Electrochemistry , 2015. 97. [Topical Meeting of the International Society of Electrochemistry . Electrochemical Properties and Applications of Advanced Carbon Materials /16./. 22.03.2015-26.03.2015, Angra dos Reis] R&D Projects: GA ČR GA13-31783S Institutional support: RVO:61388955 ; RVO:68378271 ; RVO:61388963 Keywords : boron doped diamond electrode * electrochemistry * dye-sensitized solar cell Subject RIV: CG - Electrochemistry

  6. A Conceptual Change Teaching Strategy To Facilitate High School Students' Understanding of Electrochemistry.

    Science.gov (United States)

    Niaz, Mansoor; Chacon, Eleazar

    2003-01-01

    Describes a study that used a teaching strategy based on two teaching experiments which could facilitate students' conceptual understanding of electrochemistry. Involves two sections (n=29 and n=28) of 10th grade high school students in Venezuela. Concludes that the teaching experiments facilitated student understanding of electrochemistry.…

  7. The third century of electrochemistry: Lowering the horizon or raising it further?

    Directory of Open Access Journals (Sweden)

    Hadži-Jordanov Svetomir

    2013-01-01

    Full Text Available A survey is given of the development of electrochemistry with an author’s non-hidden wish for more advanced development in future. The survey is based on past achievements of electrochemistry listed shortly here. As far as the recent state is concerned, dissatisfaction is expressed with the acceptance of electrochemistry both as profession of graduated students, and a priority field in financing research, as well. For the sake of truth an alternative view is mentioned that takes the recent state of electrochemistry as normal and in accordance with the usual course of development, (i.e. birth, rise, achieving of maximum and then decay, fading, etc., that is common in the nature. This statement is based on a belief that today electrochemistry exists on a broader basis than before, and is mainly incorporated in other (new branches of chemistry and science. Examples are given where recent electrochemistry failed to fulfill the promises (e.g., production of cheap hydrogen by means of electrocatalysts with high performance for H2 evolution, economical use of large scale fuel cells, etc.. In summarizing the recent fields of interest that covers electrochemistry, it is stressed out their diversification, specialization, complexness and interdisciplinary nature. A list of desirable highlights that could possibly help electrochemistry to improve its rating among other science branches is composed. Also, a list of author’s personal preferences is given.

  8. Electrospray ion source with reduced analyte electrochemistry

    Science.gov (United States)

    Kertesz, Vilmos [Knoxville, TN; Van Berkel, Gary [Clinton, TN

    2011-08-23

    An electrospray ion (ESI) source and method capable of ionizing an analyte molecule without oxidizing or reducing the analyte of interest. The ESI source can include an emitter having a liquid conduit, a working electrode having a liquid contacting surface, a spray tip, a secondary working electrode, and a charge storage coating covering partially or fully the liquid contacting surface of the working electrode. The liquid conduit, the working electrode and the secondary working electrode can be in liquid communication. The electrospray ion source can also include a counter electrode proximate to, but separated from, said spray tip. The electrospray ion source can also include a power system for applying a voltage difference between the working electrodes and a counter-electrode. The power system can deliver pulsed voltage changes to the working electrodes during operation of said electrospray ion source to minimize the surface potential of the charge storage coating.

  9. Electrospray ion source with reduced analyte electrochemistry

    Science.gov (United States)

    Kertesz, Vilmos; Van Berkel, Gary J

    2013-07-30

    An electrospray ion (ESI) source and method capable of ionizing an analyte molecule without oxidizing or reducing the analyte of interest. The ESI source can include an emitter having a liquid conduit, a working electrode having a liquid contacting surface, a spray tip, a secondary working electrode, and a charge storage coating covering partially or fully the liquid contacting surface of the working electrode. The liquid conduit, the working electrode and the secondary working electrode can be in liquid communication. The electrospray ion source can also include a counter electrode proximate to, but separated from, said spray tip. The electrospray ion source can also include a power system for applying a voltage difference between the working electrodes and a counter-electrode. The power system can deliver pulsed voltage changes to the working electrodes during operation of said electrospray ion source to minimize the surface potential of the charge storage coating.

  10. New applications of electrochemistry to ICF target preparation

    International Nuclear Information System (INIS)

    Electrochemistry plays a very important role in inertial confinement fusion (ICF) target preparation. This paper reports the preparation of metal foil with theoretical density by electrical chemical machining and metal nanowire array by electrodeposition on anodized aluminum oxide (AAO) template. Ti foils with surface roughness less than 30 nm and Au nanowire arrays with length about 10 μm, diameter about 300 nm were prepared. The choices of electrolyte composition and electrochemical parameters, and diameter and length control of nanowires were investigated. (authors)

  11. Mediated electrochemistry of dimethyl sulfoxide reductase promoted by carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    BERNHARDT; Paul; V

    2010-01-01

    Mediated electrochemistry of dimethyl sulfoxide reductase from Rhodobacter capsulatus (DMSOR) which is immobilized on a bare glassy carbon (GC) electrode and a carbon nanotube (CNT)-modified GC electrode was studied using the Co complex (trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)cobalt(III) ([Co(trans-diammac)] +) as a mediator.The cyclic voltammograms of different electrodes were carried out at different substrate (DMSO) concentrations.The results demonstrated that the catalytic current was increased by employing CNT as a promoter.

  12. Electrochemistry and green chemical processes: electrochemical ozone production

    Directory of Open Access Journals (Sweden)

    Leonardo M. da Silva

    2003-12-01

    Full Text Available After an introductory discussion emphasising the importance of electrochemistry for the so-called Green Chemical Processes, the article presents a short discussion of the classical ozone generation technologies. Next a revision of the electrochemical ozone production technology focusing on such aspects as: fundamentals, latest advances, advantages and limitations of this technology is presented. Recent results about fundamentals of electrochemical ozone production obtained in our laboratory, using different electrode materials (e.g. boron doped diamond electrodes, lead dioxide and DSAÒ-based electrodes also are presented. Different chemical processes of interest to the solution of environmental problems involving ozone are discussed.

  13. Electrochemistry of Inorganic Nanocrystalline Electrode Materials for Lithium Batteries

    OpenAIRE

    Vijayamohanan, K.; Kale, B. B.; A. Vadivel Murugan; C. Labrugère; Delville, M. H.; Hwang, S J; Kwon, C. W.; Campet, G.

    2003-01-01

    Traditional electrode materials are based on the redox potential difference of the electrode in the course of intercalation/deintercalation reactions. They are generally well-crystalline host compounds either with layered structure such as LiCoO2 and LiNiO2, or with tunnel structure like LiMn2O4 Nanocrystalline materials are, however, being re-evaluated recently as ‘nanoscience’ advances. The electrochemistry of this kind of materials is much different from that of traditional crystalline one...

  14. Shape Evolution of Platinum Nanocrystals by Electrochemistry

    International Nuclear Information System (INIS)

    Graphical abstract: Shape evolution of Pt nanocrystals was achieved by using square-wave-potential (SWP) method that provides driving force to separate precisely nucleation and growth stages of Pt nanocrystals in shape-controlled synthesis of Pt nanocrystals. Through careful control of the growth rate of Pt nanocrystals and the depth of oxygen adsorption, a series of Pt nanoparticles were synthesized by the SWP approach through changing the concentration of precursors and the growth potential. Abscissa and ordinate of a-i represent respectively the concentration of precursor and the applied potential. Shapes of nanoparticles of A-I were chosen under the specific precursor concentration and applied potential shown in a-i. - Abstract: The high-index facets of face-centered cubic metal have high surface energy, and the thermodynamics of crystal growth makes the high-index facets disappear during the crystal growth. The surface energy of high-index facets can be reduced through adsorption of molecules during crystal growth, and metal nanoparticles with high-index facets are thus formed. The shape-controlled synthesis of metal nanocrystals remains a big challenge even today. The shape evolution mechanism of metal nanocrystals with different facets has not yet been well elucidated. In this work, platinum nanocrystals of different shapes, octahedra with low-index facets, tetrahexahedra and concave hexoctahedron enclosed with high-index facets, were synthesized by the square-wave-potential method (SWP). The same precursor and the same adsorption molecules were used to synthesize Pt nanocrystals, but a series of parameter were varied, such as precursor concentration, growth potential, oxidative etching potential, with/without electrolyte in solution, and frequency of the SWP. This paper discusses the details about shape-controlled synthesis and proposes the preliminary mechanism of formation of Pt nanocrystals. The current study has illustrated that the electrochemical

  15. Mesomorphism and electrochemistry of thienoviologen liquid crystals.

    Science.gov (United States)

    Cospito, S; Beneduci, A; Veltri, L; Salamonczyk, M; Chidichimo, G

    2015-07-21

    The thienoviologen series 4,4'-(2,2'-bithiophene-5,5'-diyl)bis(1-alkylpridinium)X2, with = counterion is a new class of electron acceptor materials which show very interesting electrochromic and electrofluorescence properties. Depending on the length, m, of the promesogenic alkyl chains, and on the counterion, thienoviologens might become liquid crystals. Here, we present the mesomorphic behaviour, and the electrochemical and spectroelectrochemical properties in solution of new thienoviologens of the series and (I = iodide; NTf2(-) = bis(tri-fuoromethylsulfonyl)imide) with m = 8, 12. Interestingly, we found that only the compounds are liquid crystals, exhibiting a calamitic behaviour in contrast to the homologous compounds of the series with m = 9-11 and X = NTf2(-), which showed columnar rectangular mesophases. The electrochemical study here reported allowed us to explain for the first time the anomalous behaviour of these thienoviologens already observed in cyclic voltammetry, where two apparently irreversible redox processes occur. This can be explained by a comproportionation reaction in which the neutral species rapidly reduces the dication to the radical-cation, due to its strong reducing power. Electrochemical reduction of the thienoviologens causes electrochromism since a new absorption band, occurring at 660 nm in the electronic spectra, appears with the negative potential bias applied. With a LUMO level of 3.64 eV, similar to those of the C60 and of other n-type materials, these compounds can find applications in several electronics devices, where their liquid crystalline properties can be used to control film morphology and geometry, provided they have good electron mobility. PMID:26082287

  16. A Review on Direct Electrochemistry of Catalase for Electrochemical Sensors

    Directory of Open Access Journals (Sweden)

    Periasamy Arun Prakash

    2009-03-01

    Full Text Available Catalase (CAT is a heme enzyme with a Fe(III/II prosthetic group at its redox centre. CAT is present in almost all aerobic living organisms, where it catalyzes the disproportionation of H2O2 into oxygen and water without forming free radicals. In order to study this catalytic mechanism in detail, the direct electrochemistry of CAT has been investigated at various modified electrode surfaces with and without nanomaterials. The results show that CAT immobilized on nanomaterial modified electrodes shows excellent catalytic activity, high sensitivity and the lowest detection limit for H2O2 determination. In the presence of nanomaterials, the direct electron transfer between the heme group of the enzyme and the electrode surface improved significantly. Moreover, the immobilized CAT is highly biocompatible and remains extremely stable within the nanomaterial matrices. This review discusses about the versatile approaches carried out in CAT immobilization for direct electrochemistry and electrochemical sensor development aimed as efficient H2O2 determination. The benefits of immobilizing CAT in nanomaterial matrices have also been highlighted.

  17. Construction and direct electrochemistry of orientation controlled laccase electrode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [Key Laboratory of Colloid and Interface Chemistry of the Education Ministry of China, Shandong University, Jinan 250100 (China); Zhang, Jiwei [State Key Laboratory of Microbial Technology of China, Shandong University, Jinan 250100 (China); Huang, Xirong, E-mail: xrhuang@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry of the Education Ministry of China, Shandong University, Jinan 250100 (China); State Key Laboratory of Microbial Technology of China, Shandong University, Jinan 250100 (China); Wang, Tianhong, E-mail: wangtianhong@sdu.edu.cn [State Key Laboratory of Microbial Technology of China, Shandong University, Jinan 250100 (China)

    2014-03-28

    Highlights: • A recombinant laccase with Cys-6×His tag at the N or C terminus was generated. • Orientation controlled laccase electrodes were constructed via self assembly. • The electrochemical behavior of laccase electrodes was orientation dependent. • The C terminus tagged laccase was better for bioelectrocatalytic reduction of O{sub 2}. - Abstract: A laccase has multiple redox centres. Chemisorption of laccases on a gold electrode through a polypeptide tag introduced at the protein surface provides an isotropic orientation of laccases on the Au surface, which allows the orientation dependent study of the direct electrochemistry of laccase. In this paper, using genetic engineering technology, two forms of recombinant laccase which has Cys-6×His tag at the N or C terminus were generated. Via the Au-S linkage, the recombinant laccase was assembled orientationally on gold electrode. A direct electron transfer and a bioelectrocatalytic activity toward oxygen reduction were observed on the two orientation controlled laccase electrodes, but their electrochemical behaviors were found to be quite different. The orientation of laccase on the gold electrode affects both the electron transfer pathway and the electron transfer efficiency of O{sub 2} reduction. The present study is helpful not only to the in-depth understanding of the direct electrochemistry of laccase, but also to the development of laccase-based biofuel cells.

  18. Construction and direct electrochemistry of orientation controlled laccase electrode

    International Nuclear Information System (INIS)

    Highlights: • A recombinant laccase with Cys-6×His tag at the N or C terminus was generated. • Orientation controlled laccase electrodes were constructed via self assembly. • The electrochemical behavior of laccase electrodes was orientation dependent. • The C terminus tagged laccase was better for bioelectrocatalytic reduction of O2. - Abstract: A laccase has multiple redox centres. Chemisorption of laccases on a gold electrode through a polypeptide tag introduced at the protein surface provides an isotropic orientation of laccases on the Au surface, which allows the orientation dependent study of the direct electrochemistry of laccase. In this paper, using genetic engineering technology, two forms of recombinant laccase which has Cys-6×His tag at the N or C terminus were generated. Via the Au-S linkage, the recombinant laccase was assembled orientationally on gold electrode. A direct electron transfer and a bioelectrocatalytic activity toward oxygen reduction were observed on the two orientation controlled laccase electrodes, but their electrochemical behaviors were found to be quite different. The orientation of laccase on the gold electrode affects both the electron transfer pathway and the electron transfer efficiency of O2 reduction. The present study is helpful not only to the in-depth understanding of the direct electrochemistry of laccase, but also to the development of laccase-based biofuel cells

  19. Single-crystal-like NiO colloidal nanocrystal-aggregated microspheres with mesoporous structure: Synthesis and enhanced electrochemistry, photocatalysis and water treatment properties

    International Nuclear Information System (INIS)

    A new microwave-assisted hydrothermal synthetic route based on the self-assembly and subsequently controlled thermal decomposition process is proposed to fabricate nickel oxide colloidal nanocrystal aggregated microspheres (CNAMs) with mesoporous structure. XRD, EDS, SEM, TEM. FTIR, and N2 adsorption and desorption isotherm techniques are employed for morphology and structure characterizations. The as-prepared nickel oxide CNAMs, which has a high surface area (234 m2/g) with narrow pore distribution at around 3.25 nm, are composed of numerous hexagonal mesoporous nanocrystals of approximately 50–60 nm in size, and present a single-crystal-like characteristic. The experimental results also demonstrated that the CNAMs showed outstanding performance in electrochemistry, photocatalysis and waste water treatment due to their special hierarchical and mesoporous structure, presenting the promising candidate for catalysis and catalysis support materials. - Graphical abstract: CNAMs with mesoporous structure synthesized via a simple microwave-assisted hydrothermal method was applied in electrochemistry and catalysis and exhibited enhanced performance. Display Omitted - Highlights: • CNAMs with mesoporous structure are achieved via a simple microwave-assisted hydrothermal method. • Morphology, structure and pore distribution of sample particles is specifically controlled. • The samples show enhanced properties in electrochemistry and catalysis due to hierarchical structure

  20. Selenium electrochemistry. Applications in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Modern state of selenium electrochemistry is reviewed in respect of the application of electrochemical methods for the study of the behavior of this element and its quantitative analysis in the solutions of nuclear fuel cycle. The review includes the data on the redox potentials of Se in aqueous solutions, and the data on Se redox reactions, occurring at mercury and solid electrodes. Analysis of the available literature data shows that the inverse stripping voltammetry technique for trace Se concentration and determination seems to be the most promising in application for the Se determination in PUREX solutions and in radioactive wastes. The adaptation of the ISV technique for the trace Se concentration and determination in the solutions of the nuclear fuel cycle is indicated as the most prospective goal of the future experimental study. (author)

  1. Selenium electrochemistry. Applications in the nuclear fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Maslennikov, A.; Peretroukhine, V. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Physical Chemistry; David, F. [Centre National de la Recherche Scientifique (CNRS), 91 - Orsay (France); Lecomte, M. [CEA Centre d' Etudes de la Valle du Rhone, 30 - Marcoule (France). Direction du Cycle du Combustible

    1999-07-01

    Modern state of selenium electrochemistry is reviewed in respect of the application of electrochemical methods for the study of the behavior of this element and its quantitative analysis in the solutions of nuclear fuel cycle. The review includes the data on the redox potentials of Se in aqueous solutions, and the data on Se redox reactions, occurring at mercury and solid electrodes. Analysis of the available literature data shows that the inverse stripping voltammetry technique for trace Se concentration and determination seems to be the most promising in application for the Se determination in PUREX solutions and in radioactive wastes. The adaptation of the ISV technique for the trace Se concentration and determination in the solutions of the nuclear fuel cycle is indicated as the most prospective goal of the future experimental study. (author)

  2. Oxygen electrochemistry as a cornerstone for sustainable energy conversion.

    Science.gov (United States)

    Katsounaros, Ioannis; Cherevko, Serhiy; Zeradjanin, Aleksandar R; Mayrhofer, Karl J J

    2014-01-01

    Electrochemistry will play a vital role in creating sustainable energy solutions in the future, particularly for the conversion and storage of electrical into chemical energy in electrolysis cells, and the reverse conversion and utilization of the stored energy in galvanic cells. The common challenge in both processes is the development of-preferably abundant-nanostructured materials that can catalyze the electrochemical reactions of interest with a high rate over a sufficiently long period of time. An overall understanding of the related processes and mechanisms occurring under the operation conditions is a necessity for the rational design of materials that meet these requirements. A promising strategy to develop such an understanding is the investigation of the impact of material properties on reaction activity/selectivity and on catalyst stability under the conditions of operation, as well as the application of complementary in situ techniques for the investigation of catalyst structure and composition. PMID:24339359

  3. Ultra-micro-electrochemistry under irradiation; Ultramicroelectrochimie sous irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Perdicakis, M. [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement, UMR 7564 CNRS - Nancy-Univ., 54 - Villers-les-Nancy (France); Corbel, C.; Leoni, E. [Ecole Polytechnique, 91 - Palaiseau (France). Lab. CEA d' Etudes des Solides Irradies; Simon, P. [Centre National de la Recherche Scientifique (CNRS), Centre de Recherches sur les Materiaux a Hautes Temperatures, 45 - Orleans-la-Source (France)

    2007-07-01

    In this work, are exposed volt-amperometric results recorded in situ during irradiation by electrons, protons or helium ions of homogeneous solutions and solid/deionized water interfaces where the solid can be: quartz, steel or uranium oxide. In a second part, the electrochemical answer is obtained in approaching the ultra-micro-electrode in close vicinity to the solid, at a distance inferior to those corresponding to the diffusion layer of this last ones. The last part deals with the results of an experiment which is until now unique: the in situ coupling of ultra-micro-electrochemistry with Raman micro-spectrometry in order to follow the UO{sub 2} corrosion during its irradiation by He{sup 2+} particles. (O.M.)

  4. Comparative electrochemistry of technetium (V) and rhenium (V) dioxo complexes

    International Nuclear Information System (INIS)

    The heavy use of 99mTc in nuclear medicine and the recent development of 188Re radiopharmaceuticals have encouraged the comparative study of Tc and Re coordination compounds. In this work, the electrochemistry of [MvO2(amine)2]+(M = Tc, Re; amine = ethylenediamine, 1,3-diaminopropane, diethylenetriamine, triethylenetetramine) complexes is studied by cyclic voltammetry and the results are compared. The voltammograms of these compounds, obtained at different pH values, show that [ReO2(amine)2+ cations are thermodynamically stable even when protonated. On the other hand, analogous Tc compounds are not so stable and easily decompose if existing as [TcO (OH) (amine)2]2+. (author). 17 refs., 3 figs., 1 tab

  5. The electrochemistry of 13% chromium stainless steel in oilfield brines

    Energy Technology Data Exchange (ETDEWEB)

    Sidorin, Dmitry; Pletcher, Derek [Department of Chemistry, The University of Southampton, Southampton SO17 1BJ (United Kingdom); Hedges, Bill [BP Trinidad Ltd., P.O. Box 714, Port of Spain (Trinidad and Tobago)

    2005-07-25

    The electrochemistry of a 13% Cr stainless steel (API5CT L80-13Cr) in 3% NaCl containing acetate and either acetic acid or carbon dioxide at 333 K is explored using RDE voltammetry. The reduction of proton, carbonic acid and acetic acid occur simultaneously, immediately negative to the corrosion potential. Acetic acid gives a well formed reduction wave and the current densities increase with the equilibrium concentration of acetic acid in the medium; in the plateau region, the reduction is mass transport controlled. Despite this reduction process, the corrosion resistance and passivation current density are independent of the acetic acid concentration. It is confirmed that the 13% Cr stainless steel is much more resistant to corrosion that X65 carbon steel and, unlike the carbon steel, its rate of corrosion does not vary with acetic acid concentration. The properties of the passivating film appear to dominate the behaviour of the 13% Cr stainless steel. (author)

  6. The electrochemistry of 13% chromium stainless steel in oilfield brines

    International Nuclear Information System (INIS)

    The electrochemistry of a 13% Cr stainless steel (API5CT L80-13Cr) in 3% NaCl containing acetate and either acetic acid or carbon dioxide at 333 K is explored using RDE voltammetry. The reduction of proton, carbonic acid and acetic acid occur simultaneously, immediately negative to the corrosion potential. Acetic acid gives a well formed reduction wave and the current densities increase with the equilibrium concentration of acetic acid in the medium; in the plateau region, the reduction is mass transport controlled. Despite this reduction process, the corrosion resistance and passivation current density are independent of the acetic acid concentration. It is confirmed that the 13% Cr stainless steel is much more resistant to corrosion that X65 carbon steel and, unlike the carbon steel, its rate of corrosion does not vary with acetic acid concentration. The properties of the passivating film appear to dominate the behaviour of the 13% Cr stainless steel

  7. Bacterial biofilms investigated by atomic force microscopy and electrochemistry

    DEFF Research Database (Denmark)

    Hu, Yifan

    Streptococcus mutans (dental caries). AFM was used to investigate the adhesion force on single live cell surfaces. Four different strains of Staphylococcus epidermidis in liquid aqueous environments were adressed. These strains were selected because of their special surface proteins related with the initial...... attachment on the surface. High-resolution AFM imaging showed no detectable differences among the four strains. Adhesion maps using hydrophobically modified tips compared with bare hydrophilic silicon nitride tips also showed small differences only. This indicates that hydrophobic effects are not the primary...... driving forces towards adhesion. Two chemical inhibitor compounds were found to have strong effects on the adhesion between the bare tips and the bacteria. Secondly, AFM and electrochemistry were combined to study bacterial biofilm formation on Au(111)-surfaces, to determine the surface charge and growth...

  8. Facile synthesis of cuprous oxide nanoparticles by plasma electrochemistry

    Science.gov (United States)

    Liu, Jiandi; Chen, Qiang; Li, Junshuai; Xiong, Qing; Yue, Guanghui; Zhang, Xianhui; Yang, Size; Huo Liu, Qing

    2016-07-01

    We report on a simple plasma electrochemistry method for synthesizing cuprous oxide (Cu2O) nanoparticles in the presence of glucose. In this system, Ar plasma in contact with a NaCl solution was used as one electrode, and a Cu plate was immersed in the solution as the counter electrode. The plasma-solution interaction produced many reducing and oxidizing species which can react with the Cu ions released from the Cu electrode. Cu2O nanoparticles, with an average diameter of 22 +/- 6 nm, were formed under the competition of reducing and oxidizing reactions in the solution. The results show that the glucose added in the electrolyte strongly influences the properties of the products. Corresponding to high, medium, and low concentrations of glucose, the products were nanoparticles from amorphous Cu2O, polycrystalline Cu2O, and a mixture of polycrystalline Cu2O and Cu2Cl(OH)3, respectively.

  9. Electrochemistry Corrosion Properties of Pulsed Laser Welding Hastelloy C-276

    Science.gov (United States)

    Ma, G.; Niu, F.; Wu, D.; Qu, Y.

    Based on the welding quality requirement of Hastelloy C276 in the extreme environment, the electrochemistry corrosion property of laser welding Hastelloy C276 was evaluated in the neutral, acid and alkaline solutions, and the corroded surface was observed by the co-focal laser scanning microscope to confirm the corrosion mechanism. The results indicated, the corrosion trend of the weld was weaker than that of base metal in the neutral and acid solutions, but in the alkaline solutions, the corrosion trend of the base metal was weaker. However, the corrosion rate of the weld was much slower than that of base metal in all solutions. At the point of corrosion mechanism, in the acid and alkaline solutions, the base metal and weld showed the uniform corrosion. However, in the neutral solution, the selective corrosion and intergranular corrosion occurred in the base metal and the weld, respectively.

  10. AERE Harwell Applied Chemistry Division unclassified progress report and bibliography for the period 1st April 1975 to 31st March 1976

    International Nuclear Information System (INIS)

    The Progress Report is under the headings: Analytical Chemistry Group, Actinide Analysis Group, Applied Electrochemistry Group, Nuclear Fuels Group, Solid State Chemistry Group, Separation Processes Group, list of unclassified publications. (U.K.)

  11. Covalent Dimers of 1,3-Diphenylisobenzofuran for Singlet Fission: Synthesis and Electrochemistry

    Czech Academy of Sciences Publication Activity Database

    Akdag, Akin; Wahab, Abdul; Beran, Pavel; Rulíšek, Lubomír; Dron, P. I.; Ludvík, Jiří; Michl, Josef

    2015-01-01

    Roč. 80, č. 1 (2015), s. 80-89. ISSN 0022-3263 R&D Projects: GA ČR GA13-21704S; GA ČR(CZ) GA14-31419S Institutional support: RVO:61388963 ; RVO:61388955 Keywords : singlet fission * reduction potentials * electrochemistry * theoretical calculations Subject RIV: CC - Organic Chemistry; CG - Electrochemistry (UFCH-W) Impact factor: 4.721, year: 2014

  12. KEY STRUCTURAL FEATURES IN ELECTROCHEMISTRY OF Cr(0) AND Fe(0) AMINOCARBENE COMPLEXES

    Czech Academy of Sciences Publication Activity Database

    Hoskovcová, I.; Dvořák, D.; Tobrman, T.; Záliš, Stanislav; Ludvík, Jiří

    Bratislava : Slovak University of Technology, 2011 - (Melník, M.; Segĺa, P.; Tatarko, M.), s. 155-169 ISBN 978-80-227-3509-4. [International Conference on Coordination and Bioinorganic Chemistry /23./. Smolenice (SK), 05.06.2011-10.06.2011] R&D Projects: GA AV ČR IAA400400813 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * aminocarbene complexes Subject RIV: CG - Electrochemistry

  13. Catalysis in electrochemistry from fundamental aspects to strategies for fuel cell development

    CERN Document Server

    Santos, Elizabeth

    2011-01-01

    Catalysis in Electrochemistry: From Fundamental Aspects to Strategies for Fuel Cell Development is a modern, comprehensive reference work on catalysis in electrochemistry, including principles, methods, strategies, and applications. It points out differences between catalysis at gas/surfaces and electrochemical interfaces, along with the future possibilities and impact of electrochemical science on energy problems. This book contributes both to fundamental science; experience in the design, preparation, and characterization of electrocatalytic materials; and the industrial application o

  14. Electrochemical analysis of nucleic acids and new trends in protein electrochemistry

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Ostatná, Veronika; Trefulka, Mojmír; Černocká, Hana; Bartošík, Martin

    Vienna, 2009. s. 1. ISSN 1091-8213. [216th ECS Meeting with EuroCVD 17 and SOFC XI - 11th International Symposium on Solid Oxide Fuel Cells. 04.10.2009-09.10.2009, Vienna] Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : nucleic acids electrochemistry * protein electrochemistry * chronopotentiometric stripping analysis Subject RIV: BO - Biophysics

  15. Electrochemistry of nucleic acids and proteins: Towards sensors for genomics and proteomics

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Ostatná, Veronika; Dorčák, Vlastimil; Havran, Luděk; Masařík, Michal; Trefulka, Mojmír; Cahová, Kateřina; Krstic, D.; Pechan, Zdeněk; Jelen, František; Fojta, Miroslav

    Ankara, 2006. s. 64-67. ISBN 975-482-715-X. [8th International Symposium on Pharmaceutical Sciences, ISOPS-8. 13.06.2006-16.06.2006, Ankara] R&D Projects: GA AV ČR(CZ) IAA500040513; GA ČR(CZ) GA203/06/1685; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507 Keywords : electrochemical DNA biosensors * DNA electrochemistry * electrochemistry of proteins Subject RIV: BO - Biophysics

  16. Role of Palladium in the Redox Electrochemistry of Ferrocene Monocarboxylic Acid Encapsulated Within ORMOSIL Networks

    OpenAIRE

    Upadhyay, B.; P Pandey

    2005-01-01

    We report herein the effect of palladium on the redox electrochemistry of ferrocene monocarboxylic acid encapsulated within an organically modified sol-gel glass network (ORMOSIL). It has been found that amount of palladium and its geometrical distribution significantly alter the redox electrochemistry of FcMCA. The geometrical distribution of palladium has been controlled by two methods: (i) palladium is allowed to link within nanostructured network of the ORMOSIL which was subsequently avai...

  17. Electrochemistry of a ferrocene-grafted cell-penetrating peptide

    International Nuclear Information System (INIS)

    A cationic cell-penetrating peptide (CPP) labeled with both a ferrocenyl (Fc) moiety and a biotin (B) was successfully synthesized and investigated by electrochemistry. This original CPP derivative noted as Fc-CPP-B could be electrochemically detected, at a micromolar concentration, at a naked gold bead electrode. The presence of a biotin tag in the Fc-CPP-B complex allowed its complexation with avidin, which was itself tethered to a thiolated self-assembled monolayer. Such an avidin-modified gold surface, characterized by atomic force microscopy (AFM), allowed the immobilization of Fc-CPP-B onto the electrode surface, which greatly enhanced its electrochemical detection. Nevertheless, under these conditions the electrogenerated ferrocenium cation could not be reduced during the backward scan, indicating its unexpected reactivity when tethered within the avidin environment. In terms of detection and redox probe regeneration the best results were obtained at a glassy carbon electrode modified with a cation-exchange polymer. Ion-exchange voltammetry, performed under these conditions, allowed the pre-concentration of the peptide at the electrode surface thanks to the net positive charge of the CPP derivative. Interestingly, the anionic character of the polymer contributed to retain the electrogenerated cation Fc+ in the film so that it could be reduced back to its original neutral form during the reverse voltammetric scans.

  18. Electrochemistry of magnesium electrolytes in ionic liquids for secondary batteries.

    Science.gov (United States)

    Vardar, Gulin; Sleightholme, Alice E S; Naruse, Junichi; Hiramatsu, Hidehiko; Siegel, Donald J; Monroe, Charles W

    2014-10-22

    The electrochemistry of Mg salts in room-temperature ionic liquids (ILs) was studied using plating/stripping voltammetry to assess the viability of IL solvents for applications in secondary Mg batteries. Borohydride (BH4(-)), trifluoromethanesulfonate (TfO(-)), and bis(trifluoromethanesulfonyl)imide (Tf2N(-)) salts of Mg were investigated. Three ILs were considered: l-n-butyl-3-methylimidazolium (BMIM)-Tf2N, N-methyl-N-propylpiperidinium (PP13)-Tf2N, and N,N-diethyl-N-methyl(2-methoxyethyl)ammonium (DEME(+)) tetrafluoroborate (BF4(-)). Salts and ILs were combined to produce binary solutions in which the anions were structurally similar or identical, if possible. Contrary to some prior reports, no salt/IL combination appeared to facilitate reversible Mg plating. In solutions containing BMIM(+), oxidative activity near 0.8 V vs Mg/Mg(2+) is likely associated with the BMIM cation, rather than Mg stripping. The absence of voltammetric signatures of Mg plating from ILs with Tf2N(-) and BF4(-) suggests that strong Mg/anion Coulombic attraction inhibits electrodeposition. Cosolvent additions to Mg(Tf2N)2/PP13-Tf2N were explored but did not result in enhanced plating/stripping activity. The results highlight the need for IL solvents or cosolvent systems that promote Mg(2+) dissociation. PMID:25248147

  19. Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate

    Directory of Open Access Journals (Sweden)

    Chanchal K. Mitra

    2009-02-01

    Full Text Available We have studied the direct electrochemistry of horseradish peroxidase (HRP coupled to gold nanoparticles (AuNP using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i glutathione and (ii lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP conjugate showed characteristic redox peaks at a gold electrode. It displayed good electrocatalytic response to the reduction of H2O2, with good sensitivity and without any electron mediator. The covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the different concentrations of H2O2 showed the characteristics of Michaelis Menten enzyme kinetics with an optimum pH between 7.0 to 8.0. The preparation of the sensor involves single layer of enzyme, which can be carried out efficiently and is also highly reproducible when compared to other systems involving the layer-by-layer assembly, adsorption or encapsulation of the enzyme. The immobilized AuNP-HRP can be used for immunosensor applications

  20. Electrochemistry of vitamin E hydro-alcoholic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Giacomelli, Cristiano; Giacomelli, Fernando Carlos; Alves, Luciano Ortigara; Timbola, Ana Karina; Spinelli, Almir [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Quimica]. E-mail: spin@qmc.ufsc.br

    2004-10-01

    The electrochemistry of vitamin E hydro-alcoholic solutions of pH 3.1 to 12.1 was studied by cyclic voltammetry, controlled potential electrolysis, thin layer chromatography and UV-Vis, IR and {sup 13}C NMR spectroscopy. The presence of water was found to have important implications on the chemical stability of electrogenerated species. Vitamin E exhibits three oxidation peaks in hydro-alcoholic solutions at glassy carbon electrodes in contrast to just a single peak in other solvents. Although the electrochemical reaction at the first peak was found to be the same in presence and in absence of water, which is a one-step two-electron transfer process, two heterogeneous electrochemical reactions and three homogeneous chemical reactions following this peak were established based on electrochemical evidences for the first time in alcohol aqueous conditions. This insight is considered to be very important provided the mediator character of vitamin E in the electron transfer between aqueous and lipid phase in the organism. (author)

  1. Electrochemistry of vitamin E hydro-alcoholic solutions

    International Nuclear Information System (INIS)

    The electrochemistry of vitamin E hydro-alcoholic solutions of pH 3.1 to 12.1 was studied by cyclic voltammetry, controlled potential electrolysis, thin layer chromatography and UV-Vis, IR and 13C NMR spectroscopy. The presence of water was found to have important implications on the chemical stability of electrogenerated species. Vitamin E exhibits three oxidation peaks in hydro-alcoholic solutions at glassy carbon electrodes in contrast to just a single peak in other solvents. Although the electrochemical reaction at the first peak was found to be the same in presence and in absence of water, which is a one-step two-electron transfer process, two heterogeneous electrochemical reactions and three homogeneous chemical reactions following this peak were established based on electrochemical evidences for the first time in alcohol aqueous conditions. This insight is considered to be very important provided the mediator character of vitamin E in the electron transfer between aqueous and lipid phase in the organism. (author)

  2. Predominating stable adsorption and direct electrochemistry of glucose oxidase on carbon nanotubes by oxygen-containing groups

    Institute of Scientific and Technical Information of China (English)

    Chun Hai Yang; Cheng Guo Hu; Sheng Shui Hu

    2007-01-01

    Stable adsorption and direct electrochemistry of glucose oxidase (GOx) occurred on nitric acid (HNO3)-treated multi-walled carbon nanotubes (MWNTs) instead of as-received MWNTs, demonstrating the critical roles of oxygen-containing groups in stable adsorption and direct electrochemistry of GOx on carbon nanotubes (CNTs).

  3. Mono and dinuclear iridium, rhodium and ruthenium complexes containing chelating carboxylato pyrazine ligands: Synthesis, molecular structure and electrochemistry

    Czech Academy of Sciences Publication Activity Database

    Govindaswamy, P.; Therrien, B.; Süss-Fink, G.; Štěpnička, P.; Ludvík, Jiří

    2007-01-01

    Roč. 692, č. 8 (2007), s. 1661-1671. ISSN 0022-328X R&D Projects: GA MŠk LC510; GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40400503 Keywords : dinuclear complexes * iridium * rhodium * ruthenium * electrochemistry Subject RIV: CG - Electrochemistry Impact factor: 2.168, year: 2007

  4. go to top Electrochemistry and Spectroscopy of an Energetic Material FOX-7. A molecular Approach to Degradation Mechanism

    Czech Academy of Sciences Publication Activity Database

    Šimková, Ludmila; Urban, Jiří; Klíma, Jiří; Ludvík, Jiří

    2012-01-01

    Roč. 4, č. 6 (2012), s. 554-560. ISSN 2035-1755 R&D Projects: GA MŠk ME09002 Institutional support: RVO:61388955 Keywords : 2,2-Dinitroethene-1,1-Diamine * Degradation Mechanism * Electrochemistry Subject RIV: CG - Electrochemistry

  5. Martian Dust Devil Electron Avalanche Process and Associated Electrochemistry

    Science.gov (United States)

    Jackson, Telana L.; Farrell, William M.; Delory, Gregory T.; Nithianandam, Jeyasingh

    2010-01-01

    Mars' dynamic atmosphere displays localized dust devils and larger, global dust storms. Based on terrestrial analog studies, electrostatic modeling, and laboratory work these features will contain large electrostatic fields formed via triboelectric processes. In the low-pressure Martian atmosphere, these fields may create an electron avalanche and collisional plasma due to an increase in electron density driven by the internal electrical forces. To test the hypothesis that an electron avalanche is sustained under these conditions, a self-consistent atmospheric process model is created including electron impact ionization sources and electron losses via dust absorption, electron dissociation attachment, and electron/ion recombination. This new model is called the Dust Devil Electron Avalanche Model (DDEAM). This model solves simultaneously nine continuity equations describing the evolution of the primary gaseous chemical species involved in the electrochemistry. DDEAM monitors the evolution of the electrons and primary gas constituents, including electron/water interactions. We especially focus on electron dynamics and follow the electrons as they evolve in the E field driven collisional gas. When sources and losses are self-consistently included in the electron continuity equation, the electron density grows exponentially with increasing electric field, reaching an equilibrium that forms a sustained time-stable collisional plasma. However, the character of this plasma differs depending upon the assumed growth rate saturation process (chemical saturation versus space charge). DDEAM also shows the possibility of the loss of atmospheric methane as a function of electric field due to electron dissociative attachment of the hydrocarbon. The methane destruction rates are presented and can be included in other larger atmospheric models.

  6. STM, SECPM, AFM and Electrochemistry on Single Crystalline Surfaces

    Directory of Open Access Journals (Sweden)

    Ulrich Stimming

    2010-08-01

    Full Text Available Scanning probe microscopy (SPM techniques have had a great impact on research fields of surface science and nanotechnology during the last decades. They are used to investigate surfaces with scanning ranges between several 100 mm down to atomic resolution. Depending on experimental conditions, and the interaction forces between probe and sample, different SPM techniques allow mapping of different surface properties. In this work, scanning tunneling microscopy (STM in air and under electrochemical conditions (EC-STM, atomic force microscopy (AFM in air and scanning electrochemical potential microscopy (SECPM under electrochemical conditions, were used to study different single crystalline surfaces in electrochemistry. Especially SECPM offers potentially new insights into the solid-liquid interface by providing the possibility to image the potential distribution of the surface, with a resolution that is comparable to STM. In electrocatalysis, nanostructured catalysts supported on different electrode materials often show behavior different from their bulk electrodes. This was experimentally and theoretically shown for several combinations and recently on Pt on Au(111 towards fuel cell relevant reactions. For these investigations single crystals often provide accurate and well defined reference and support systems. We will show heteroepitaxially grown Ru, Ir and Rh single crystalline surface films and bulk Au single crystals with different orientations under electrochemical conditions. Image studies from all three different SPM methods will be presented and compared to electrochemical data obtained by cyclic voltammetry in acidic media. The quality of the single crystalline supports will be verified by the SPM images and the cyclic voltammograms. Furthermore, an outlook will be presented on how such supports can be used in electrocatalytic studies.

  7. LIGA-based microsystem manufacturing:the electrochemistry of through-mold depostion and material properties.

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, James J. (Sandia National Laboratories, Livermore, CA); Goods, Steven Howard (Sandia National Laboratories, Livermore, CA)

    2005-06-01

    The report presented below is to appear in ''Electrochemistry at the Nanoscale'', Patrik Schmuki, Ed. Springer-Verlag, (ca. 2005). The history of the LIGA process, used for fabricating dimensional precise structures for microsystem applications, is briefly reviewed, as are the basic elements of the technology. The principal focus however, is on the unique aspects of the electrochemistry of LIGA through-mask metal deposition and the generation of the fine and uniform microstructures necessary to ensure proper functionality of LIGA components. We draw from both previously published work by external researchers in the field as well as from published and unpublished studies from within Sandia.

  8. Electrochemistry of Single Metalloprotein and DNA‐Based Molecules at Au(111) Electrode Surfaces

    DEFF Research Database (Denmark)

    Salvatore, Princia; Zeng, Dongdong; Karlsen, Kasper Kannegård;

    2013-01-01

    We have briefly overviewed recent efforts in the electrochemistry of single transition metal complex, redox metalloprotein, and redox‐marked oligonucleotide (ON) molecules. We have particularly studied self‐assembled molecular monolayers (SAMs) of several 5′‐C6‐SH single‐ (ss) and double‐strand (ds......) ONs immobilized on Au(111) electrode surfaces via AuS bond formation, using a combination of nucleic acid chemistry, electrochemistry and electrochemically controlled scanning tunnelling microscopy (in situ STM). Ds ONs stabilized by multiply charged cations and locked nucleic acid (LNA) monomers...

  9. Electrochemically modulated liquid chromatography: Theoretical investigations and applications from the perspectives of chromatography and interfacial electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Keller, David W.

    2005-05-01

    Electrochemically modulated liquid chromatography (EMLC) employs a conductive material as both a stationary phase for chromatographic separations and as a working electrode for performing electrochemistry experiments. This dual functionality gives EMLC the capacity to manipulate chromatographic separations by changing the potential applied (E{sub app}) to the stationary phase with respect to an external reference. The ability to monitor retention as a function of E{sub app} provides a means to chromatographically monitor electrosorption processes at solid-liquid interfaces. In this dissertation, the retention mechanism for EMLC is examined from the perspective of electrical double layer theory and interfacial thermodynamics. From the chromatographic data, it is possible to determine the interfacial excess ({Lambda}) of a solute and changes in interfacial tension (d{gamma}) as a function of both E{sub app} and the supporting electrolyte concentration. Taken together, these two experimentally manipulated parameters can be examined within the context of the Gibbs adsorption equation to delineate the contribution of a variety of interfacial properties, including the charge of solute on the stationary phase and the potential of zero charge (PZC), to the mechanism behind EMLC-based retention. The chromatographic probing of interfacial phenomena is complemented by electroanalytical experiments that exploit the ability to monitor the electronic current flowing through an EMLC column. Cyclic voltammetry and chronoamperometry of an EMLC column are used to determine the electronic performance characteristics of an EMLC column. An electrochemical flow injection analysis of a column is provided in which the current required to maintain a constant E{sub app} is monitored and provides a way to examine the influence that acetonitrile and supporting electrolyte composition, flow rate, column backpressure, and ionic strength have on the structure of electrified interfaces.

  10. SOME RECENT STUDIES IN RUGHENIUM ELECTROCHEMISTRY AND ELECTROCATALYSIS.

    Energy Technology Data Exchange (ETDEWEB)

    MARINKOVIC, N.S.; VUKMIROVIC, M.B.; ADZIC, R.R.

    2006-08-01

    Ruthenium is a metal of a considerable importance in electrochemical science and technology. It is a catalyst or co-catalyst material in Pt-Ru alloys for methanol- and reformate hydrogen-oxidation in fuel cells, while ruthenium oxide, a component in chlorine-evolution catalysts, represents an attractive material for electrochemical supercapacitors. Its facile surface oxidation generates an oxygen-containing species that provides active oxygen in some reactions. Ru sites in Pt-Ru catalysts increase the ''CO tolerance'' of Pt in the catalytic oxidation-reaction in direct methanol fuel cells (DMFC) and in reformate hydrogen-oxidation in proton exchange membrane fuel cells (PEMFC). The mechanism of Ru action is not completely understood, although current consensus revolves around the so-called ''bifunctional mechanism'' wherein Ru provides oxygenated species to oxidize CO that blocks Pt sites, and has an electronic effect on Pt-CO interaction. While various studies of polycrystalline Ru go back several decades those involving single crystal surfaces and the structural sensitivity of reactions on Ru surfaces emerged only recently. Using well-ordered single crystalline surfaces brings useful information as the processes on realistic catalysts are far too complex to allow identification of the microscopic reaction steps. In this article, we focus on progress in model systems and conditions, such as electrochemistry and electrocatalysis on bare and Pt-modified well-ordered Ru(0001) and Ru(10{bar 1}0) single-crystal surfaces. We also review current understanding of the mechanistic principles of Pt-Ru systems and a new development of a Pt submonolayer on Ru support electrocatalyst. Ruthenium crystallizes in a hexagonal close-packed structure, (hcp). Figure 1.1 shows the two single crystal surfaces of Ru. The Ru(0001) surface possesses the densest, i.e. hexagonal arrangement of atoms, Fig. 1.1a. The other plane, Ru(10{bar 1}0), can have

  11. Effect of Cooperative Learning Strategies on Students' Understanding of Concepts in Electrochemistry

    Science.gov (United States)

    Acar, Burcin; Tarhan, Leman

    2007-01-01

    The present study was conducted to investigate the degree of effectiveness of cooperative learning instruction over a traditional approach on 11th grade students' understanding of electrochemistry. The study involved forty-one 11th grade students from two science classes with the same teacher. To determine students' misconceptions concerning…

  12. Effects of Jigsaw and Animation Techniques on Students' Understanding of Concepts and Subjects in Electrochemistry

    Science.gov (United States)

    Doymus, Kemal; Karacop, Ataman; Simsek, Umit

    2010-01-01

    This study investigated the effect of jigsaw cooperative learning and animation versus traditional teaching methods on students' understanding of electrochemistry in a first-year general chemistry course. This study was carried out in three different classes in the department of primary science education during the 2007-2008 academic year. The…

  13. 电化学学术会议年历%Electrochemistry Calendar

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    International Symposium in Buenos Aires: Challenges on Rechargeable Lithium Oxygen Batteries Date: 17-19 September, 2012 Location: Buenos Aires, Argentina Sponsored by : Consejo Nacional de Investigaciones Cientificas y T6cnicas & International Society of Electro-chemistry (ISE)

  14. A novel BF2-chelated azadipyrromethene-fullerene dyad: synthesis, electrochemistry and photodynamics.

    Science.gov (United States)

    Amin, Anu N; El-Khouly, Mohamed E; Subbaiyan, Navaneetha K; Zandler, Melvin E; Fukuzumi, Shunichi; D'Souza, Francis

    2012-01-01

    The synthesis, structure, electrochemistry and photodynamics of a BF(2)-chelated azadipyrromethene-fullerene dyad are reported in comparison with BF(2)-chelated azadipyrromethene without fullerene. The attachment of fullerene resulted in efficient generation of the triplet excited state of the azadipyrromethene via photoinduced electron transfer. PMID:22083226

  15. A detailed approach to model transport, heterogeneous chemistry, and electrochemistry in solid-oxide fuel cells

    OpenAIRE

    Janardhanan, Vinod

    2007-01-01

    This book lays out a numerical framework for the detailed description of heterogeneous chemistry, electrochemistry and porous media transport in solid-oxide fuel cells (SOFC). Assuming hydrogen as the only electrochemically active species, a modified Butler-Volmer equation is used to model the electrochemical charge transfer.

  16. Conceptual Difficulties Experienced by Senior High School Students of Electrochemistry: Electrochemical (Galvanic) and Electrolytic Cells.

    Science.gov (United States)

    Garnett, Pamela J.; Treagust, David F.

    1992-01-01

    This research used semistructured interviews to investigate students' (n=32) understanding of electrochemistry following a 7-9 week course of instruction. Three misconceptions were identified and incorporated with five previously reported into an alternative framework about electric current involving drifting electrons. Also noted was the tendency…

  17. Inquiry-Based Laboratory Activities in Electrochemistry: High School Students' Achievements and Attitudes

    Science.gov (United States)

    Sesen, Burcin Acar; Tarhan, Leman

    2013-01-01

    This study aimed to investigate the effects of inquiry-based laboratory activities on high school students' understanding of electrochemistry and attitudes towards chemistry and laboratory work. The participants were 62 high school students (average age 17 years) in an urban public high school in Turkey. Students were assigned to experimental (N =…

  18. Synthesis, Molecular Structure, and Electrochemistry of 1-Ferrocenyl-1,2-dicarba-closo-dodecaboranes

    Czech Academy of Sciences Publication Activity Database

    Korotvička, A.; Šnajdr, I.; Štěpnička, P.; Císařová, I.; Janoušek, Zbyněk; Kotora, M.

    -, č. 15 (2013), s. 2789-2798. ISSN 1434-1948 Grant ostatní: GA ČR(CZ) GAP207/11/0338; GAČR(CZ) GAP207/11/0705 Institutional support: RVO:61388963 Keywords : carboranes * metallocenes * structure elucidation * electrochemistry * addition Subject RIV: CA - Inorganic Chemistry Impact factor: 2.965, year: 2013

  19. Isoflurane as a solvent for electrochemistry. Electrooxidation study of icosahedral carborane anions in four different solvents

    Czech Academy of Sciences Publication Activity Database

    Wahab, Abdul; Kvapilová, Hana; Klíma, Jiří; Michl, Josef; Ludvík, Jiří

    2013-01-01

    Roč. 689, JAN 2013 (2013), s. 257-261. ISSN 1572-6657 R&D Projects: GA MŠk ME09002; GA ČR GC203/09/J058 Institutional support: RVO:61388955 ; RVO:61388963 Keywords : isoflurane * relative permitivity * icosahedral carborane anions Subject RIV: CG - Electrochemistry Impact factor: 2.871, year: 2013

  20. Electrochemistry at the edge of a single graphene layer in a nanopore

    DEFF Research Database (Denmark)

    Banerjee, Sutanuka; Shim, Jeong; Rivera, J.;

    2013-01-01

    We study the electrochemistry of single layer graphene edges using a nanopore-based structure consisting of stacked graphene and AlO dielectric layers. Nanopores, with diameters ranging from 5 to 20 nm, are formed by an electron beam sculpting process on the stacked layers. This leads to a unique...

  1. Electrochemistry as a Tool for Study, Delvelopment and Promotion of Catalytic Reactions

    DEFF Research Database (Denmark)

    Petrushina, Irina

    of Fermi level by electrochemical production of promoters, reducing or oxidizing current carriers of the catalyst support (O2-, H+, Na+). This type1 was abbreviated as EEPP. In Capters 4-7, the results of my research are given as examples of use of electrochemistry as a tool for study, promotion and...

  2. In-situ Liquid Electron Microscopy Setups for Investigation of Nanoscale Electrochemistry

    DEFF Research Database (Denmark)

    Jensen, Eric; Møller-Nilsen, Rolf Erling Robberstad; Canepa, Silvia;

    2014-01-01

    -situ electrochemistry and has achieved ~10 nm resolution. Such systems are important tools for developing sustainable technology and for understanding nanoscale phenomena. However, both systems suffer from interacting with theelectron beam, which is a high-voltage radiation source, and therefore initial experiments...

  3. Semiconductor electrochemistry of coal pyrite. Final technical report, September 1990--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    Osseo-Asare, K.; Wei, D.

    1996-01-01

    This project is concerned with the physiochemical processes occuring at the pyrite/aqueous interface, in the context of coal cleaning, desulfurization, and acid mine drainage. The use of synthetic particles of pyrite as model electrodes to investigate the semiconductor electrochemistry of pyrite is employed.

  4. Three-Electrode Analytical and Preparative Electrochemistry in Micro-Volume Hanging Droplets

    OpenAIRE

    Perez Jimenez, Ana Isabel; Challier, Lylian; Di Pisa, Margherita; Guille-Collignon, Manon; Lemaître, Frédéric; Lavielle, Solange; Mansuy, Christelle; Amatore, Christian; Labbé, Eric; Buriez, Olivier

    2015-01-01

    Three-electrode micro-cells equipped with a conventional reference electrode (SCE) were easily constructed based on micro-volume droplets suspended by capillary forces to the fritted glass of the SCE bridge. Working and counter electrodes were simply inserted through the droplet surface, allowing classical electrochemistry to be readily performed in minute samples.

  5. Functionalizing Arrays of Transferred Monolayer Graphene on Insulating Surfaces by Bipolar Electrochemistry

    DEFF Research Database (Denmark)

    Koefoed, Line; Pedersen, Emil Bjerglund; Thyssen, Lena;

    2016-01-01

    Development of versatile methods for graphene functionalization is necessary before use in applications such as composites or as catalyst support. In this study, bipolar electrochemistry is used as a wireless functionalization method to graft 4-bromobenzenediazonium on large (10 × 10 mm2) monolayer...

  6. Electrochemistry of 1-X-12-Y-CB11-Me10 - carborane anions in liquid CO2

    Czech Academy of Sciences Publication Activity Database

    Wahab, Abdul; Stepp, Brian R.; Klíma, Jiří; Michl, Josef; Ludvík, Jiří

    Prague: J. Heyrovský Instotute of Physical Chemistry, v.v.i, 2010 - (Hudská, V.; Ludvík, J.). s. 42 ISBN 978-80-87351-06-2. [The Heyrovský Discussion. Electrochemistry of Organic Molecules and Coordination Compounds /43./. 30.05.2010-03.06.2010, Třešť] R&D Projects: GA MŠk LC510; GA AV ČR IAA400550708 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : electrochemistry * carborane anions Subject RIV: CG - Electrochemistry

  7. Microbial Electrochemistry and its Application to Energy and Environmental Issues

    Science.gov (United States)

    Hastings, Jason Thomas

    Microbial electrochemistry forms the basis of a wide range of topics from microbial fuel cells to fermentation of carbon food sources. The ability to harness microbial electron transfer processes can lead to a greener and cleaner future. This study focuses on microbial electron transfer for liquid fuel production, novel electrode materials, subsurface environments and removal of unwanted byproducts. In the first chapter, exocellular electron transfer through direct contact utilizing passive electrodes for the enhancement of bio-fuel production was tested. Through the application of microbial growth in a 2-cell apparatus on an electrode surface ethanol production was enhanced by 22.7% over traditional fermentation. Ethanol production efficiencies of close to 95% were achieved in a fraction of the time required by traditional fermentation. Also, in this chapter, the effect of exogenous electron shuttles, electrode material selection and resistance was investigated. Power generation was observed using the 2-cell passive electrode system. An encapsulation method, which would also utilize exocellular transfer of electrons through direct contact, was hypothesized for the suspension of viable cells in a conductive polymer substrate. This conductive polymer substrate could have applications in bio-fuel production. Carbon black was added to a polymer solution to test electrospun polymer conductivity and cell viability. Polymer morphology and cell viability were imaged using electron and optical microscopy. Through proper encapsulation, higher fuel production efficiencies would be achievable. Electron transfer through endogenous exocellular protein shuttles was observed in this study. Secretion of a soluble redox active exocellular protein by Clostridium sp. have been shown utilizing a 2-cell apparatus. Cyclic voltammetry and gel electrophoresis were used to show the presence of the protein. The exocellular protein is capable of reducing ferrous iron in a membrane separated

  8. Serendipity: Genesis of the Electrochemical Instrumentation at Princeton Applied Research Corporation

    Science.gov (United States)

    Flato, J. B.

    2007-01-01

    Princeton Applied Research Corporation (PAR) was a small electronic instrument company in early 1960s but once they entered electrochemistry they were very successful. Since then they have developed and designed successful instruments with their tremendous knowledge and have made great contribution to the field of analytical chemistry.

  9. Direct electrochemistry of glucose oxidase on the hydroxyapatite/Nafion composite film modified electrode and its application for glucose biosensing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A novel glucose biosensor was constructed by immobilizing the glucose oxidase(GOD) on a hydroxyapatite(HAp)/Nafion composite film modified glassy carbon electrode(GCE) and applied to the highly selective and sensitive determination of glucose.With the cooperation of HAp and Nafion,the composite film played an important role in enhancing the stability and sensitivity of the biosensor.The results demonstrate that the GOD adsorbed onto the HAp/Nafion composite film exhibits a pair of welldefined nearly reversible redox peaks and fine catalysis to the oxidation of glucose companied with the consumption of dissolved oxygen.On the basis of the decrease of the reduction current of dissolved oxygen at the applied potential of -0.80 V(vs.SCE) upon the addition of glucose,the concentration of glucose could be detected sensitively and selectively.The decreased reduction current was linear with the concentration of glucose in the range of 0.12―2.16 mM.The detection limit and sensitivity were 0.02 mM(S/N=3) and 6.75 mA·M-1,respectively.All the results demonstrate that HAp/Nafion composite film provides a novel and efficient platform for the immobilization of enzymes and realizes the direct electrochemistry.The composite materials should have potential applications in the fabrication of third-generation biosensors.

  10. Direct electrochemistry of glucose oxidase on the hydroxyapatite/Nafion composite film modified electrode and its application for glucose biosensing

    Institute of Scientific and Technical Information of China (English)

    MA RongNa; WANG Bin; LIU Yan; LI Jing; ZHAO Qian; WANG GuoTao; JIA WenLi; WANG HuaiSheng

    2009-01-01

    A novel glucose biosensor was constructed by immobilizing the glucose oxidase (GOD) on a hydroxyapatite (Hap)/Nafion composite film modified glassy carbon electrode (GCE) and applied to the highly selective and sensitive determination of glucose.With the cooperation of Hap and Nation,the composite film played an important role in enhancing the stability and sensitivity of the biosensor.The results demonstrate that the GOD adsorbed onto the Hap/Nation composite film exhibits a pair of welldefined nearly reversible redox peaks and fine catalysis to the oxidation of glucose companied with the consumption of dissolved oxygen.On the basis of the decrease of the reduction current of dissolved oxygen at the applied potential of-0.80 V (vs.SCE) upon the addition of glucose,the concentration of glucose could be detected sensitively and selectively.The decreased reduction current was linear with the concentration of glucose in the range of 0.12-2.16 mM.The detection limit and sensitivity were 0.02 mM (S/N=3) and 6.75 mA·M~(-1),respectively.All the results demonstrate that Hap/Nafion composite film provides a novel and efficient platform for the immobilization of enzymes end realizes the direct electrochemistry.The composite materials should have potential applications in the fabrication of third-generation biosensors.

  11. A Preliminary Study of Some of the Learning and Assessment Difficulties in Connection with O-Level Electrochemistry.

    Science.gov (United States)

    Hillman, R. A. H.; And Others

    1981-01-01

    Describes a study which explored some difficulties related to technical and nontechnical vocabulary and the structure of the examination questions in electrochemistry. Includes results from a sample of 1,500 students in the fourth forms. (DS)

  12. Electrochemistry and in situ Raman spectroelectrochemistry of low and high quality boron doped diamond layers in aqueous electrolyte solution

    Czech Academy of Sciences Publication Activity Database

    Vlčková Živcová, Zuzana; Frank, Otakar; Petrák, Václav; Tarábková, Hana; Vacík, Jiří; Nesládek, M.; Kavan, Ladislav

    2013-01-01

    Roč. 87, JAN 2013 (2013), s. 518-525. ISSN 0013-4686 R&D Projects: GA AV ČR IAA400400804; GA AV ČR KAN200100801 Grant ostatní: European Commission CORDIS(XE) FP7-ENERGY-2010-FET, projekt 256617 Institutional support: RVO:61389005 ; RVO:61388955 ; RVO:68378271 Keywords : boron doped diamond * electrochemistry * aqueous electrolyte solution Subject RIV: CG - Electrochemistry Impact factor: 4.086, year: 2013

  13. Nanoplasmonic biosensor: coupling electrochemistry to localized surface plasmon resonance spectroscopy on nanocup arrays.

    Science.gov (United States)

    Zhang, Diming; Lu, Yanli; Jiang, Jing; Zhang, Qian; Yao, Yao; Wang, Ping; Chen, Bilian; Cheng, Qiaoyuan; Liu, Gang Logan; Liu, Qingjun

    2015-05-15

    The nanoscale Lycurgus cup arrays were hybrid structures of nanocups and nanoparticles with ultrasensitivity to refractive index change. In this study, an electrochemical localized surface plasmon resonance (LSPR) sensor was developed by coupling electrochemistry to LSPR spectroscopy measurement on the nanoscale cup arrays (nanoCA). Based on the combination of electrochemistry and LSPR measurement, the electrochemical LSPR on nanoCA was observed with significant resonance wavelength shifts in electrochemical modulation. The synchronous implementation of cyclic voltammetry and optical transmission spectrum can be used to obtain multiply sensing information and investigate the enhancement for LSPR from electrochemical scanning. The electrochemical enhanced LSPR was utilized as biosensor to detect biomolecules. The electrochemical LSPR biosensor with synchronous electrochemical and optical implement showed higher sensitivity than that of conventional optical LSPR measurement. Detecting with multi-transducer parameters and high sensitivity, the electrochemical LSPR provided a promising approach for chemical and biological detection. PMID:25172029

  14. Modeling the Electrochemistry of an SOFC through the Electrodes and Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Emily M.; Recknagle, Kurtis P.; Khaleel, Mohammad A.

    2011-12-01

    This paper describes a distributed electrochemistry model of the solid oxide fuel cell (SOFC) electrodes and electrolyte. The distributed electrochemistry (DEC) model solves the transport, reactions, and electric potential through the thickness of the SOFC electrodes. The DEC model allows the local conditions within the electrodes to be studied and allows for a better understanding of how electrochemical and microstructural parameters affect the electrodes. In this paper the governing equations and implementation of the DEC model are presented along with several case studies which are used to investigate the sensitivity of the cathode to the microstructural and electrochemical parameters of the model and to explore methods of improving the electrochemical performance of the SOFC cathode.

  15. Proceedings of the conference on electrochemistry of carbon allotropes: Graphite, fullerenes and diamond

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, K. [ed.] [Lawrence Berkeley National Lab., CA (United States); Scherson, D. [ed.] [Case Western Reserve Univ., Cleveland, OH (United States)

    1998-02-01

    This conference provided an opportunity for electrochemists, physicists, materials scientists and engineers to meet and exchange information on different carbon allotropes. The presentations and discussion among the participants provided a forum to develop recommendations on research and development which are relevant to the electrochemistry of carbon allotropes. The following topics which are relevant to the electrochemistry of carbon allotropes were addressed: Graphitized and disordered carbons, as Li-ion intercalation anodes for high-energy-density, high-power-density Li-based secondary batteries; Carbons as substrate materials for catalysis and electrocatalysis; Boron-doped diamond film electrodes; and Electrochemical characterization and electrosynthesis of fullerenes and fullerene-type materials. Abstracts of the presentations are presented.

  16. Development of a controlled-distance electrochemistry arrangement to be used in power plant environments

    International Nuclear Information System (INIS)

    This publication presents the state-of-the-art of the controlled-distance electrochemistry (CDE) arrangement developed at VTT. Due to the possibility to control accurately the distance between two electrodes, the CDE arrangement makes possible electrochemical measurements in poorly-conductive media such as simulated coolants of light water reactor systems. This experimental arrangement has now been developed into a versatile electrochemical tool, which can be used for thin-layer electrochemistry (TLEC), wall-jet ring-disc and contact electric impedance (CEI) as well as contact electric resistance (CER) measurements. This report comprises results from the years 1997-1999 and summarises the different possible TLEC configurations and electrode locations as well as the development of a bellows-driven CDE system. (orig.)

  17. Application of Nuclear Microprobes towards Understanding Complex Ore Geo-electrochemistry

    Directory of Open Access Journals (Sweden)

    Szymanski R.

    2012-10-01

    Full Text Available We report on recent development on the CSIRO Nuclear Microprobe (NMP towards catering for long exposure mapping required for large area scanning. A new data collection system based on Labview FPGA highly co-ordinated with beam transport sits at the heart of the upgrade. These upgrades are discussed and an example of the systems use for μ-Particle Induced X-ray Emission (PIXE analysis in the area of complex ore geo-electrochemistry is briefly described.

  18. Lithium insertion into TiO2 (anatase): electrochemistry, Raman spectroscopy, and isotope labeling

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav

    2014-01-01

    Roč. 18, č. 8 (2014), s. 2297-2306. ISSN 1432-8488 R&D Projects: GA ČR GA13-07724S Grant ostatní: COST(XE) CM1104 Institutional support: RVO:61388955 Keywords : TITANIUM-DIOXIDE ANATASE * LI-INSERTION * NANOCRYSTALLINE TiO2 Subject RIV: CG - Electrochemistry Impact factor: 2.446, year: 2014

  19. Electrochemistry of 3,5-dihalogeno-4-hydroxybenzonitriles (ionixyl and bromoxynil) in non-aqueous media

    Czech Academy of Sciences Publication Activity Database

    Sokolová, Romana; Machníková, Eva; Hromadová, Magdaléna; Pospíšil, Lubomír

    2005-01-01

    Roč. 1, č. 1 (2005), s. 153-153. ISSN 1336-7242. [Zjazd chemických spoločností /57./. 04.09.2005-08.09.2005, Tatranské Matliare] R&D Projects: GA ČR GA203/03/0821; GA AV ČR IAA400400505; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : electron transfer reactions * electrodes * pesticides Subject RIV: CG - Electrochemistry

  20. Electrochemistry-Assisted Top-Down Characterization of Disulfide-Containing Proteins

    OpenAIRE

    Zhang, Yun; Cui, Weidong; Zhang, Hao; Dewald, Howard D.; Chen, Hao

    2012-01-01

    Covalent disulfide bond linkage in a protein represents an important challenge for mass spectrometry (MS)-based top-down protein structure analysis as it reduces the backbone cleavage efficiency for MS/MS dissociation. This study presents a strategy for solving this critical issue via integrating electrochemistry (EC) online with top-down MS approach. In this approach, proteins undergo electrolytic reduction in an electrochemical cell to break disulfide bonds and then online ionized into gase...

  1. Power Ultrasound in Electrochemistry From Versatile Laboratory Tool to Engineering Solution

    CERN Document Server

    Pollet, Bruno

    2012-01-01

    The use of power ultrasound to promote industrial electrochemical processes, or sonoelectrochemistry, was first discovered over 70 years ago, but recently there has been a revived interest in this field. Sonoelectrochemistry is a technology that is safe, cost-effective, environmentally friendly and energy efficient compared to other conventional methods.? The book contains chapters on the following topics, contributed from leading researchers in academia and industry:?Use of electrochemistry as a tool to investigate Cavitation Bubble DynamicsSonoelectroanalysisSonoelectrochemistry in environme

  2. Application of N-doped graphene modified carbon ionic liquid electrode for direct electrochemistry of hemoglobin

    International Nuclear Information System (INIS)

    Nitrogen-doped graphene (NG) was synthesized and used for the investigation on direct electrochemistry of hemoglobin (Hb) with a carbon ionic liquid electrode as the substrate electrode. Due to specific characteristics of NG such as excellent electrocatalytic property and large surface area, direct electron transfer of Hb was realized with enhanced electrochemical responses appearing. Electrochemical behaviors of Hb on the NG modified electrode were carefully investigated with the electrochemical parameters calculated. The Hb modified electrode exhibited excellent electrocatalytic reduction activity toward different substrates, such as trichloroacetic acid and H2O2, with wider dynamic range and lower detection limit. These findings show that NG can be used for the preparation of chemically modified electrodes with improved performance and has potential applications in electrochemical sensing. - Graphical abstract: The utilization of N-doped graphene enables direct electrochemistry of hemoglobin with a pair of well-defined redox peaks appearing. - Highlights: • Nitrogen-doped graphene (NG) was synthesized by a solvothermal method. • NG was used for the investigation on direct electrochemistry of hemoglobin with carbon ionic liquid electrode. • The Hb modified electrode exhibited excellent electrocatalytic activity toward different substrates

  3. Application of N-doped graphene modified carbon ionic liquid electrode for direct electrochemistry of hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei, E-mail: swyy26@hotmail.com [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); Dong, Lifeng, E-mail: donglifeng@qust.edu.cn [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Department of Physics, Astronomy, and Materials Science, Missouri State University, Springfield, MO 65897 (United States); Deng, Ying; Yu, Jianhua [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Wang, Wencheng [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); Zhu, Qianqian [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China)

    2014-06-01

    Nitrogen-doped graphene (NG) was synthesized and used for the investigation on direct electrochemistry of hemoglobin (Hb) with a carbon ionic liquid electrode as the substrate electrode. Due to specific characteristics of NG such as excellent electrocatalytic property and large surface area, direct electron transfer of Hb was realized with enhanced electrochemical responses appearing. Electrochemical behaviors of Hb on the NG modified electrode were carefully investigated with the electrochemical parameters calculated. The Hb modified electrode exhibited excellent electrocatalytic reduction activity toward different substrates, such as trichloroacetic acid and H{sub 2}O{sub 2}, with wider dynamic range and lower detection limit. These findings show that NG can be used for the preparation of chemically modified electrodes with improved performance and has potential applications in electrochemical sensing. - Graphical abstract: The utilization of N-doped graphene enables direct electrochemistry of hemoglobin with a pair of well-defined redox peaks appearing. - Highlights: • Nitrogen-doped graphene (NG) was synthesized by a solvothermal method. • NG was used for the investigation on direct electrochemistry of hemoglobin with carbon ionic liquid electrode. • The Hb modified electrode exhibited excellent electrocatalytic activity toward different substrates.

  4. Achieving direct electrochemistry of glucose oxidase by one step electrochemical reduction of graphene oxide and its use in glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Shamsipur, Mojtaba; Amouzadeh Tabrizi, Mahmoud, E-mail: mahmoud.tabrizi@gmail.com

    2014-12-01

    In this paper, the direct electrochemistry of glucose oxidase (GOD) was accomplished at a glassy carbon electrode modified with electrochemically reduced graphene oxide/sodium dodecyl sulfate (GCE/ERGO/SDS). A pair of reversible peaks is exhibited on GCE/ERGO/SDS/GOD by cyclic voltammetry. The peak-to-peak potential separation of immobilized GOD is 28 mV in 0.1 M phosphate buffer solution (pH 7.0) with a scan rate of 50 mV/s. The average surface coverage is 2.62 × 10{sup −10} mol cm{sup −2}. The resulting biosensor exhibited a good response to glucose with linear range from 1 to 8 mM (R{sup 2} = 0.9878), good reproducibility and detection limit of 40.8 μM. The results from the biosensor were similar (± 5%) to those obtained from the clinical analyzer. - Highlights: • A direct electron transfer reaction of glucose oxidase was observed on GCE/ERGO/SDS. • This composite film was successfully applied in preparation of glucose biosensor. • The detection limit of the biosensor was estimated to be 40.8 μM. • The results from the sensor were similar to those obtained from the clinical analyzer.

  5. Correlation of stoichiometries for Rb+ extraction determined by mass spectrometry and electrochemistry at liquid|liquid interfaces.

    Science.gov (United States)

    Stockmann, Tom J; Montgomery, Anne-Marie; Ding, Zhifeng

    2012-07-17

    The electrochemical extraction of rubidium at micro water|1,2-dichloroethane (w|DCE) and water|room-temperature ionic liquid (w|RTIL) interfaces housed at the tip of a 25-μm capillary using octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in the TRans Uranic EXtraction (TRUEX) process, was examined. Rubidium is of great interest in a modern spent nuclear fuel cycle as well as toward myocardial perfusion imaging utilizing (82)Sr/(82)Rb isotopic generators. The ligand-to-metal stoichiometry (n:1) and overall complexation constant (β) for interfacial complexation reactions induced by an applied potential were determined by the interfacial electrochemistry. One stoichiometry, n = 2, was observed at the w|DCE interface with β = 3.3 × 10(4). In the w|RTIL system, two rubidium salt solutions were employed: RbNO(3) and RbNO(3) plus Rb(2)SO(4). The former demonstrated a stoichiometry of n = 2 and β = 2.4 × 10(6), while the latter showed n = 4 and β = 3.3 × 10(12). These stoichiometries of the reaction were confirmed by electrospray ionization mass spectrometry, using an emulsion generated by shaking water and DCE phases containing the dissolved metal and ligand, respectively. Both RbCMPO(+) and RbCMPO(2)(+) complexes were observed. The influence of ion pair interactions in this system will be discussed. PMID:22816784

  6. Flavonoid electrochemistry: a review on the electroanalytical applications

    Directory of Open Access Journals (Sweden)

    Eric S. Gil

    2013-06-01

    Full Text Available Flavonoids are polyphenolic compounds widespread in vegetal kingdom. They present a C-15 skeleton, which is divided into three units A, B and C. Unit C is an oxygen containing heterocyclic, whose oxidation state and saturation level define major subclasses. Units A and B are aromatic rings, in which four major types of substituents, i. e. hydroxyl, methoxyl, prenyl and glycosides, lead to over 8000 different flavonoids. The great healthy-protecting value of these phytochemical biomarkers has attracted the attention of scientific community. Their main biological actions include anticancer and anti-inflammatory properties, which are strictly linked to antioxidant activities. So that, electroanalysis have been extensively applied on mechanistic studies and also for analytical determinations. This review presents the state of the art regarding the main applications of electroanalysis on the flavonoid research. The approaches on redox behavior characterization leading to a better understanding of structure antioxidant activity relationships are highlighted.

  7. Improvement of capabilities of the Distributed Electrochemistry Modeling Tool for investigating SOFC long term performance

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Galdamez, Rinaldo A.; Recknagle, Kurtis P.

    2012-04-30

    This report provides an overview of the work performed for Solid Oxide Fuel Cell (SOFC) modeling during the 2012 Winter/Spring Science Undergraduate Laboratory Internship at Pacific Northwest National Laboratory (PNNL). A brief introduction on the concept, operation basics and applications of fuel cells is given for the general audience. Further details are given regarding the modifications and improvements of the Distributed Electrochemistry (DEC) Modeling tool developed by PNNL engineers to model SOFC long term performance. Within this analysis, a literature review on anode degradation mechanisms is explained and future plans of implementing these into the DEC modeling tool are also proposed.

  8. Chrono-potentiometry by chemical re-dissolution - Electrochemistry in two phase medium

    International Nuclear Information System (INIS)

    In this document which comprises two research thesis, the first one addresses the technique of chrono-potentiometry by chemical re-dissolution (or potentiometric stripping analysis). The author, after a presentation of this technique, reports the search for relationships which govern this analytical technique with respect to diffusion transport regimes imposed to species involved in the pre-concentration and chemical re-dissolution stages. The second research thesis addresses dispersed media like emulsions, micro-emulsions and micellar solutions which are interesting potential applications in organic electrochemistry. The author recalls some properties of tensio-active compounds, and then describes electrochemical investigations and electro-synthesis performed within these media

  9. Electrochemistry of NiTi wires/springs subjected to static/cyclicloadings

    Czech Academy of Sciences Publication Activity Database

    Racek, Jan; Šittner, Petr; Heller, Luděk; Pilch, Jan; Sedlák, Petr; Kadeřávek, Lukáš

    Amsterdam: Elsevier Ltd, 2015 - (San Juan, J.; López-Echarri, A.; Nó, M.; López, G.), s. 965-969. (2). ISSN 2214-7853. [International Conference on Martensitic Transformations ICOMAT 2014. Bilbao (ES), 06.07.2014-11.07.2014] R&D Projects: GA ČR GA14-15264S; GA ČR GB14-36566G Institutional support: RVO:68378271 ; RVO:61388998 Keywords : shape memory alloy * NiTi wires/springs * corrosion fatigue * cyclic loading * electrochemistry Subject RIV: BM - Solid Matter Physics ; Magnetism

  10. Teaching Students to Use Electrochemistry as a Probe of Molecular Behavior

    Science.gov (United States)

    Holder, Grant N.

    1999-11-01

    Undergraduate instruction in electrochemistry is often not as exhaustive as given in spectroscopic or chromatographic techniques. In particular, it is not typical to expose students to experiments highlighting the qualitative aspects of electrochemical methods. We have addressed this opportunity by incorporating into upper-level undergraduate laboratories experiments utilizing modern, computer-controlled electrochemical workstations to probe molecular behavior. To this end, exercises of appropriate difficulty are described for calculating rate constants, surface coverage, and deducing electron-transfer mechanisms. These have been observed to be challenging and stimulating for student investigators.

  11. Hydrogen Peroxide Biosensor Based on the Direct Electrochemistry of Myoglobin Immobilized in Poly-3-Hydroxybutyrate Film

    Directory of Open Access Journals (Sweden)

    Xiang Ma

    2005-01-01

    Full Text Available Direct electrochemistry of myoglobin (Mb was observed in a stable film composed of a natural lipid polymer (poly-3-hydroxybutyrate and Mb, the film of which was modified on a pyrolytic graphite electrode. The apparent formal potential of Mb was at about -260 mV in an acetate buffer solution with pH 5.0. Moreover, Mb in the polymer film exhibited catalytic activity towards the reduction of hydrogen peroxide (H2O2. Consequently, an unmediated biosensor for H2O2 was prepared with a linear range from 1.0×10-7 to 4.0×10-4 M.

  12. In situ STM imaging and direct electrochemistry of Pyrococcus furiosus ferredoxin assembled on thiolate-modified Au(111) surfaces

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Christensen, Hans Erik Mølager; Ooi, Bee Lean; Ulstrup, Jens

    2004-01-01

    We have addressed here electron transfer (ET) of Pyrococcus furiosus ferredoxin (PfFd, 7.5 kDa) in both homogeneous solution using edge plane graphite (EPG) electrodes and in the adsorbed state by electrochemistry on surface-modified single-crystal Au(111) electrodes, This has been supported by...... electrode surface modified by the same functional group monolayer and to address diffusionless direct electrochemistry, as well as surface microstructures of the protein monolayer. PfFd molecules were found to assemble on either mercaptopropionic acid (MPA) or cysteine-modified Au(111) surfaces in stable...

  13. Nanoflake-like SnS₂ matrix for glucose biosensing based on direct electrochemistry of glucose oxidase.

    Science.gov (United States)

    Yang, Zhanjun; Ren, Yanyan; Zhang, Yongcai; Li, Juan; Li, Hongbo; Hu, Xiaochun Huang Xiaoya; Xu, Qin

    2011-07-15

    A novel biosensor is developed based on immobilization of proteins on nanoflake-like SnS₂ modified glass carbon electrode (GCE). With glucose oxidase (GOD) as a model, direct electrochemistry of the GOD/nanoflake-like SnS₂ is studied. The prepared SnS₂ has large surface area and can offer favorable microenvironment for facilitating the electron transfer between protein and electrode surface. The properties of GOD/SnS₂ are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV), respectively. The immobilized enzyme on nanoflake-like SnS₂ retains its native structure and bioactivity and exhibits a surface-controlled, reversible two-proton and two-electron transfer reaction with the apparent electron transfer rate constant (k(s)) of 3.68 s⁻¹. The proposed biosensor shows fast amperometric response (8s) to glucose with a wide linear range from 2.5 × 10⁻⁵ M to 1.1 × 10⁻³ M, a low detection limit of 1.0 × 10⁻⁵ M at signal-to-noise of 3 and good sensitivity (7.6 ± 0.5 mA M⁻¹ cm⁻²). The resulting biosensor has acceptable operational stability, good reproducibility and excellent selectivity and can be successfully applied in the reagentless glucose sensing at -0.45 V. It should be worthwhile noting that it opens a new avenue for fabricating excellent electrochemical biosensor. PMID:21592767

  14. High temperature electrochemistry related to light water reactor corrosion

    International Nuclear Information System (INIS)

    The present work deals with corrosion problems related to conditions which prevail in a WWER primary circuit. We had a two-fold aim: (A) electrochemical methods were applied to characterise the hydrothermally produced oxides of the cladding material (Zr-1%Nb) of nuclear fuel elements used in Russian made power reactors of WWER type, and (B) a number of possible reference electrodes were investigated with a view to high temperature applications. (A) Test specimens made of the cladding material, Zr-1%Nb, were immersed into an autoclave, filled with an aqueous solution typical to a WWER primary circuit, and were treated for different periods of time up to 28 weeks. The electrode potentials were measured and electrochemical impedance spectra (EIS) were taken regularly both as a function of oxidation time and temperature. This rendered information on the overall kinetics of oxide growth. By combining in situ and ex situ impedance measurements, with a particular view of the temperature dependence of EIS, we concluded that the high frequency region of impedance spectra is relevant to the presence of oxide layer on the alloy. This part of the spectra was treated in terms of a parallel CPE||Rox equivalent circuit (CPE denoting constant phase element, Rox ohmic resistor). The CPE element was understood as a dispersive resistance in terms of the continuous time random walk theory by Scher and Lax. This enabled us to tell apart electrical conductance and oxide growth with a model of charge transfer and recombination within the oxide layer as rate determining steps. (B) Three types of reference electrodes were tested within the framework of the LIRES EU5 project: (i) external Ag/AgCl, (ii) Pt/Ir alloy and (iii) Pd(Pt) double polarised active electrode. The most stable of the electrodes was found to be the Pt/Ir one. The Ag/AgCl electrode showed good stability after an initial period of some days, while substantial drifts were found for the Pd(Pt) electrode. EIS spectra of the

  15. Direct electrochemistry behavior of Cytochrome c on silicon dioxide nanoparticles-modified electrode

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A newfangled direct electrochemistry behavior of Cytochrome c (Cyt c) was found on glassy carbon (GC) electrode modified with the silicon dioxide (SiO2) nanoparticles by physical adsorption. A pair of stable and well-defined redox peaks of Cyt c′ quasi-reversible electrochemical reaction were obtained with a heterogeneous electron transfer rate constant of 1.66×10-3 cm/s and a formal potential of 0.069 V (vs. Ag/AgCl) (0.263 V versus NHE) in 0.1 mol/L pH 6.8 PBS. Both the size and the amount of SiO2 nanoparticles could influence the electron transfer between Cyt c and the electrode. Electrostatic interaction which is between the negative nanoparticle surface and positively charged amino acid residues on the Cyt c surface is of importance for the stability and reproducibility toward the direct electron transfer of Cyt c. It is suggested that the modification of SiO2 nanoparticles proposes a novel approach to realize the direct electrochemistry of proteins.

  16. Fabrication of graphene–platinum nanocomposite for the direct electrochemistry and electrocatalysis of myoglobin

    International Nuclear Information System (INIS)

    In this paper a platinum (Pt) nanoparticle decorated graphene (GR) nanosheet was synthesized and used for the investigation on direct electrochemistry of myoglobin (Mb). By integrating GR–Pt nanocomposite with Mb on the surface of carbon ionic liquid electrode (CILE), a new electrochemical biosensor was fabricated. UV-Vis absorption and FT-IR spectra indicated that Mb remained its native structure in the nanocomposite film. Electrochemical behaviors of Nafion/Mb–GR–Pt/CILE were investigated with a pair of well-defined redox peak appeared, which indicated that direct electron transfer of Mb was realized on the underlying electrode with the usage of the GR–Pt nanocomposite. The fabricated electrode showed good electrocatalytic activity to the reduction of trichloroacetic acid in the linear range from 0.9 to 9.0 mmol/L with the detection limit as 0.32 mmol/L (3σ), which showed potential application for fabricating novel electrochemical biosensors and bioelectronic devices. - Highlights: ► The GR–Pt nanocomposite was synthesized and employed for the fabrication of electrochemical biosensor. ► Direct electrochemistry of Mb in the nanocomposite was realized. ► The prepared biosensor exhibited excellent electrochemical response to the reduction of TCA

  17. Fabrication of graphene–platinum nanocomposite for the direct electrochemistry and electrocatalysis of myoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei, E-mail: swyy26@hotmail.com [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Li, Linfang [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Lei, Bingxin [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); Li, Tongtong; Ju, Xiaomei; Wang, Xiuzheng; Li, Guangjiu [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Sun, Zhenfan [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China)

    2013-05-01

    In this paper a platinum (Pt) nanoparticle decorated graphene (GR) nanosheet was synthesized and used for the investigation on direct electrochemistry of myoglobin (Mb). By integrating GR–Pt nanocomposite with Mb on the surface of carbon ionic liquid electrode (CILE), a new electrochemical biosensor was fabricated. UV-Vis absorption and FT-IR spectra indicated that Mb remained its native structure in the nanocomposite film. Electrochemical behaviors of Nafion/Mb–GR–Pt/CILE were investigated with a pair of well-defined redox peak appeared, which indicated that direct electron transfer of Mb was realized on the underlying electrode with the usage of the GR–Pt nanocomposite. The fabricated electrode showed good electrocatalytic activity to the reduction of trichloroacetic acid in the linear range from 0.9 to 9.0 mmol/L with the detection limit as 0.32 mmol/L (3σ), which showed potential application for fabricating novel electrochemical biosensors and bioelectronic devices. - Highlights: ► The GR–Pt nanocomposite was synthesized and employed for the fabrication of electrochemical biosensor. ► Direct electrochemistry of Mb in the nanocomposite was realized. ► The prepared biosensor exhibited excellent electrochemical response to the reduction of TCA.

  18. Merits of online electrochemistry liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS).

    Science.gov (United States)

    Looi, Wen Donq; Brown, Blake; Chamand, Laura; Brajter-Toth, Anna

    2016-03-01

    A new online electrochemistry/liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS) system with a simple electrochemical thin-layer flow-through cell was developed and tested using N,N-dimethyl-p-phenylenediamine (DMPA) as a model probe. Although oxidation of DMPA is observed as a result of ionization of LS in positive ion mode LS DESI, application of voltage to the online electrochemical (EC) cell in EC/LS DESI MS increases yields of oxidation products. An advantage of LS DESI MS is its sensitivity in aqueous electrolyte solutions, which improves efficiency of electrochemical reactions in EC/LS DESI MS. In highly conductive low pH aqueous buffer solutions, oxidation efficiency is close to 100 %. EC/ESI MS typically requires mixed aqueous/organic solvents and low electrolyte concentrations for efficient ionization in MS, limiting efficiency of electrochemistry online with MS. Independently, the results verify higher electrochemical oxidation efficiency during positive mode ESI than during LS DESI. Graphical abstract Detection of DMPA oxidation in online electrochemical cell with EC/LS DESI MS. PMID:26886744

  19. Na-Ion Battery Anodes: Materials and Electrochemistry.

    Science.gov (United States)

    Luo, Wei; Shen, Fei; Bommier, Clement; Zhu, Hongli; Ji, Xiulei; Hu, Liangbing

    2016-02-16

    also outlined, where graphene oxide was employed as dehydration agent and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) was used to unzip wood fiber. Furthermore, surface modification by atomic layer deposition technology is introduced, where we discover that a thin layer of Al2O3 can function to encapsulate Sn nanoparticles, leading to a much enhanced cycling performance. We also highlight recent work about the phosphorene/graphene anode, which outperformed other anodes in terms of capacity. The aromatic organic anode is also studied as anode with very high initial sodiation capacity. Furthermore, electrochemical intercalation of Na ions into reduced graphene oxide is applied for fabricating transparent conductors, demonstrating the great feasibility of Na ion intercalation for optical applications. PMID:26783764

  20. Relative Effect of Lecture Method Supplemented with Music and Computer Animation on Senior Secondary School Students' Retention in Electrochemistry

    Science.gov (United States)

    Akpoghol, T. V.; Ezeudu, F. O.; Adzape, J. N.; Otor, E. E.

    2016-01-01

    The study investigated the effects of Lecture Method Supplemented with Music (LMM) and Computer Animation (LMC) on senior secondary school students' retention in electrochemistry in Makurdi metropolis. Three research questions and three hypotheses guided the study. The design of the study was quasi experimental, specifically the pre-test,…

  1. Impact of Interactive Multimedia Module with Pedagogical Agents on Students' Understanding and Motivation in the Learning of Electrochemistry

    Science.gov (United States)

    Osman, Kamisah; Lee, Tien Tien

    2014-01-01

    The Electrochemistry topic is found to be difficult to learn due to its abstract concepts involving macroscopic, microscopic, and symbolic representation levels. Studies have shown that animation and simulation using information and communication technology (ICT) can help students to visualize and hence enhance their understanding in learning…

  2. Effectiveness of Interactive Multimedia Module with Pedagogical Agent (IMMPA) in the Learning of Electrochemistry: A Preliminary Investigation

    Science.gov (United States)

    Lee, Tien Tien; Osman, Kamisah

    2011-01-01

    Electrochemistry is found to be a difficult topic to learn due to its abstract concepts that involve the macroscopic, microscopic and symbolic representation levels. Research showed that animation and simulation using Information and Communication Technology (ICT) can help students to visualize and hence enhance students' understanding in learning…

  3. Hydrogenated graphenes by birch reduction: influence of electron and proton sources on hydrogenation efficiency, magnetism, and electrochemistry

    Czech Academy of Sciences Publication Activity Database

    Eng, A.Y.S.; Sofer, Z.; Huber, Š.; Bouša, D.; Maryško, Miroslav; Pumera, M.

    2015-01-01

    Roč. 21, č. 7 (2015), 16828-16838. ISSN 0947-6539 Institutional support: RVO:68378271 Keywords : hydrogen ated graphenes * birch reduction * magnetism * electrochemistry * hydrogen ation efficiency Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.731, year: 2014

  4. Effects of Lecture Method Supplemented with Music and Computer Animation on Senior Secondary School Students' Academic Achievement in Electrochemistry

    Science.gov (United States)

    Akpoghol, T. V.; Ezeudu, F. O.; Adzape, J. N.; Otor, E. E.

    2016-01-01

    The study investigated the effects of Lecture Method Supplemented with Music (LMM) and Computer Animation (LMC) on senior secondary school students' academic achievement in electrochemistry in Makurdi metropolis. Six research questions and six hypotheses guided the study. The design of the study was quasi experimental, specifically the pre-test,…

  5. Structural investigation of oxovanadium(IV) Schiff base complexes: X-ray crystallography, electrochemistry and kinetic of thermal decomposition

    Czech Academy of Sciences Publication Activity Database

    Asadi, M.; Asadi, Z.; Savaripoor, N.; Dušek, Michal; Eigner, Václav; Shorkaei, M.R.; Sedaghat, M.

    2015-01-01

    Roč. 136, Feb (2015), 625-634. ISSN 1386-1425 R&D Projects: GA ČR(CZ) GAP204/11/0809 Institutional support: RVO:68378271 Keywords : Oxovanadium(IV) complexes * Schiff base * Kinetics of thermal decomposition * Electrochemistry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.353, year: 2014

  6. In situ generation of copper cations and complexation with tebuconazole in a hyphenation of electrochemistry with mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Schröder, Detlef; Norková, Renáta

    2013-01-01

    Roč. 338, 15 MAR (2013), s. 45-49. ISSN 1387-3806 R&D Projects: GA ČR GP13-21409P Institutional support: RVO:61388963 Keywords : electrochemical ion generation * ESI-MS * coupling * fungicide * tebuconazole * soil solution Subject RIV: CG - Electrochemistry Impact factor: 2.227, year: 2013

  7. Scanning electrochemical cell microscopy: a versatile technique for nanoscale electrochemistry and functional imaging.

    Science.gov (United States)

    Ebejer, Neil; Güell, Aleix G; Lai, Stanley C S; McKelvey, Kim; Snowden, Michael E; Unwin, Patrick R

    2013-01-01

    Scanning electrochemical cell microscopy (SECCM) is a new pipette-based imaging technique purposely designed to allow simultaneous electrochemical, conductance, and topographical visualization of surfaces and interfaces. SECCM uses a tiny meniscus or droplet, at the end of a double-barreled (theta) pipette, for high-resolution functional imaging and nanoscale electrochemical measurements. Here we introduce this technique and provide an overview of its principles, instrumentation, and theory. We discuss the power of SECCM in resolving complex structure-activity problems and provide considerable new information on electrode processes by referring to key example systems, including graphene, graphite, carbon nanotubes, nanoparticles, and conducting diamond. The many longstanding questions that SECCM has been able to answer during its short existence demonstrate its potential to become a major technique in electrochemistry and interfacial science. PMID:23560932

  8. Immobilization and direct electrochemistry of copper-containing enzymes on active carbon

    Institute of Scientific and Technical Information of China (English)

    SUN Dongmei; CAI Chenxin; XING Wei; LU Tianhong

    2004-01-01

    Two typical and important copper-containing enzymes, laccase (Lac) and tyrosinase (Tyr), have been immobilized on the surface of active carbon with simple adsorption method. The cyclic voltammetric results indicated that the active carbon could promote the direct electron transfer of both Lac and Tyr and a pair of well-defined and nearly symmetric redox peaks appeared on the cyclic voltammograms of Lac or Tyr with the formal potential, E0′, independent on the scan rate. The further experimental results showed that the immobilized copper-containing oxidase displayed an excellent electrocatalytic activity to the electrochemical reduction of O2. The immobilization method presented here has several advantages, such as simplicity, easy to operation and keeping good activity of enzyme etc., and could be further used to study the direct electrochemistry of other redox proteins and enzymes and fabricate the catalysts for biofuel cell.

  9. Electrochemistry Modeling of Proton Exchange Membrane (PEM) Water Electrolysis for Hydrogen Production

    International Nuclear Information System (INIS)

    An electrochemistry model was developed to analyse the J-V characteristics of a Proton Exchange Membrane (PEM) water electrolyzer for hydrogen production. The Butler-Volmer equation and water transport characteristics through electrolyte membrane were employed to simulate the electrode activation over-potential and membrane ohmic over-potential, respectively. The modeling results are found to agree reasonably well with experimental data published in the literature. The parametric simulations show that the ohmic over-potential is relatively small with typical water content in the membrane. Compared with the cathode over-potential, the anode over-potential is more significant and constitutes the major source of voltage loss. The high anode over-potential is due to the relatively slow oxidation kinetics, which is related to anode material property and microstructure. This model can be integrated with a photovoltaic or wind turbine model to predict the performance of sustainable hydrogen production systems and optimise their designs. (authors)

  10. Two-Step Bipolar Electrochemistry: Generation of Composition Gradient and Visual Screening of Electrocatalytic Activity.

    Science.gov (United States)

    Termebaf, Hajar; Shayan, Mohsen; Kiani, Abolfazl

    2015-12-01

    Bipolar electrochemistry (BE) is employed for both creating electrocatalysts composition gradient and visual screening of the prepared composition on a single substrate in just two experiment runs. In a series of proof-of-principle experiments, we demonstrate gradient electrodeposition of Ni-Cu using BE; then the electrocatalytic activity of the prepared composition gradient toward the hydrogen evolution reaction (HER) is visually screened in the BE system using array of BPEs. Moreover, the morphology and the chemical composition of the Ni-Cu gradient are screened along the length of the bipolar electrode (BPE). By measuring the potential gradient over the BPE, it is also demonstrated that by controlling the concentration of the metals precursor and the supporting electrolyte, the length of the bipolar electrodeposited gradient can be controlled. PMID:26595192

  11. Direct Electrochemistry of Glucose Oxidase at a Gold Electrode Modified with Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yuan Zhuobin

    2003-12-01

    Full Text Available The direct electrochemistry of glucose oxidase (GOD was accomplished at a gold electrode modified with single-wall carbon nanotubes (SWNTs. A pair of welldefined redox peaks was obtained for GOD with the reduction peak potential at –0.465 V and a peak potential separation of 23 mV at pH 7.0. Both FT-IR spectra and the dependence of the reduction peak current on the scan rate revealed that GOD adsorbed onto the SWNT surfaces. The redox wave corresponds to the redox center of the flavin adenine dinucleotide(FAD of the GOD adsorbate. The electron transfer rate of GOD redox reaction was greatly enhanced at the SWNT-modified electrode. The peak potential was shown to be pH dependent. Verified by spectral methods, the specific enzyme activity of GOD adsorbates at the SWNTs appears to be retained.

  12. Direct electrochemistry and electrocatalysis of myoglobin in dodecyltrimethylammonium bromide film modified carbon ceramic electrode

    Institute of Scientific and Technical Information of China (English)

    Yuan Zhen Zhou; Hui Wang; She Ying Dong; An Xiang Tian; Zhi Xian He; Bin Chen

    2011-01-01

    Direct electrochemistry and electrocatalysis of myoglobin (Mb) were studied with Mb immobilized on dodecyltrimethylammonium bromide (DTAB) film modified carbon ceramic (CC) electrode. Cyclic voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb (FeⅡ/FeⅢ) at about -0.3 V vs. SCE (pH = 6.98). The currents of the redox peak were linear to scan rate, and rate constant (Ks) was estimated to be 3.03 s-1. The formal potential (E01) of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of-36.44 mV/pH, implying that the electron transfer between DTAB and CC electrodes is accompanied by proton transportation. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide (H2O2).

  13. Mechanistic studies of pyridinium electrochemistry: alternative chemical pathways in the presence of CO2.

    Science.gov (United States)

    Peroff, A G; Weitz, E; Van Duyne, R P

    2016-01-21

    Protonated heterocyclic amines, such as pyridinium, have been utilized as catalysts in the electrocatalytic reduction of carbon dioxide. While these represent a new and exciting class of electrocatalysts, the details of the mechanism and faradaic processes occurring in solution are unclear. We report a series of cyclic voltammetry experiments involving Pt, Ag, Au, and Cu electrodes, under both aqueous and nonaqueous conditions, directed towards gaining an improved mechanistic understanding of pyridinium electrochemistry. Surface-enhanced Raman (SER) spectroelectrochemistry was also performed on Cu film-over-nanosphere electrodes in order to identify adsorbed species. It was found that the reduction potential of pyridinium (-0.58 V vs. SCE) and its electrochemical reversibility are unique features of platinum electrodes. In contrast, the reduction potentials on Ag, Au, and Cu electrodes are ∼400 mV more negative than Pt in both the presence and the absence of CO2. SER spectroelectrochemistry of pyridinium solutions shows no evidence for a pyridinium radical or a pyridinium ion. Increased cathodic current in the presence of CO2 is only detected at scan rates less than 10 mV s(-1) in aqueous solutions. The addition of CO2 resulted in a shift in the potential for the hydrogen evolution reaction. Pyridinium electrochemistry was observed under nonaqueous conditions; however no increase in cathodic current was observed when CO2 was added to the solution. Based on this set of results it is concluded that the reduction potential of pyridinium is surface dependent, CO2 acts as a pseudo-reserve of H(+), and pyridinium and CO2 create an alternative mechanism for hydrogen evolution. PMID:26670579

  14. Applied Electromagnetics

    International Nuclear Information System (INIS)

    These proceedings contain papers relating to the 3rd Japanese-Bulgarian-Macedonian Joint Seminar on Applied Electromagnetics. Included are the following groups: Numerical Methods I; Electrical and Mechanical System Analysis and Simulations; Inverse Problems and Optimizations; Software Methodology; Numerical Methods II; Applied Electromagnetics

  15. Application of Carbon-Microsphere-Modified Electrodes for Electrochemistry of Hemoglobin and Electrocatalytic Sensing of Trichloroacetic Acid

    OpenAIRE

    Wen-Cheng Wang; Li-Jun Yan; Fan Shi; Xue-Liang Niu; Guo-Lei Huang; Cai-Juan Zheng; Wei Sun

    2015-01-01

    By using the hydrothermal method, carbon microspheres (CMS) were fabricated and used for electrode modification. The characteristics of CMS were investigated using various techniques. The biocompatible sensing platform was built by immobilizing hemoglobin (Hb) on the micrometer-sized CMS-modified electrode with a layer of chitosan membrane. On the cyclic voltammogram, a couple of quasi-reversible cathodic and anodic peaks appeared, showing that direct electrochemistry of Hb with the working e...

  16. Carrier concentration profiling in magnetic GaMnSb/GaSb investigated by electrochemistry capacitance-voltage profiler

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Depth profiles of carrier concentrations in Ga- MnSb/GaSb are investigated by electrochemistry capacitance-voltage profiler and electrolyte of Tiron. The carrier concentration in GaMnSb/GaSb measured by this method is coincident with the results of Hall and X-ray diffraction measurements. It is indicated that most of the Mn atoms in GaMnSb take the site of Ga, play a role of acceptors, and provide shallow acceptor level(s).

  17. Anthraquinone as a Redox Label for DNA: Synthesis, Enzymatic Incorporation, and Electrochemistry of Anthraquinone-Modified Nucleosides, Nucleotides, and DNA

    Czech Academy of Sciences Publication Activity Database

    Balintová, Jana; Pohl, Radek; Horáková Brázdilová, Petra; Vidláková, Pavlína; Havran, Luděk; Fojta, Miroslav; Hocek, Michal

    2011-01-01

    Roč. 17, č. 50 (2011), s. 14063-14073. ISSN 0947-6539 R&D Projects: GA MŠk(CZ) LC06035; GA MŠk LC512; GA AV ČR(CZ) IAA400040901 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : anthraquinone * DNA * electrochemistry * nucleosides * oligonucleotides Subject RIV: CC - Organic Chemistry Impact factor: 5.925, year: 2011

  18. The mechanism of the nano-CeO{sub 2} films deposition by electrochemistry method as coated conductor buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yuming; Cai, Shuang [Department of Physics, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of High Temperature Superconductors, Shanghai 200444 (China); Liang, Ying, E-mail: yliang@ecust.edu.cn [Institute of Nuclear Technology and Application, School of Science, East China University of Science and Technology, Shanghai 200237 (China); Bai, Chuanyi; Liu, Zhiyong; Guo, Yanqun; Cai, Chuanbing [Department of Physics, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of High Temperature Superconductors, Shanghai 200444 (China)

    2015-05-15

    Highlights: • Crack-free CeO{sub 2} film thicker than 200 nm was prepared on NiW substrate by ED method. • Different electrochemical processes as hydroxide/metal mechanisms were identified. • The CeO{sub 2} precursor films deposited by ED method were in nano-scales. - Abstract: Comparing with conventional physical vapor deposition methods, electrochemistry deposition technique shows a crack suppression effect by which the thickness of CeO{sub 2} films on Ni–5 at.%W substrate can reach a high value up to 200 nm without any cracks, make it a potential single buffer layer for coated conductor. In the present work, the processes of CeO{sub 2} film deposited by electrochemistry method are detailed investigated. A hydroxide reactive mechanism and an oxide reactive mechanism are distinguished for dimethyl sulfoxide and aqueous solution, respectively. Before heat treatment to achieve the required bi-axial texture performance of buffer layers, the precursor CeO{sub 2} films are identified in nanometer scales. The crack suppression for electrochemistry deposited CeO{sub 2} films is believed to be attributed to the nano-effects of the precursors.

  19. The mechanism of the nano-CeO2 films deposition by electrochemistry method as coated conductor buffer layers

    International Nuclear Information System (INIS)

    Highlights: • Crack-free CeO2 film thicker than 200 nm was prepared on NiW substrate by ED method. • Different electrochemical processes as hydroxide/metal mechanisms were identified. • The CeO2 precursor films deposited by ED method were in nano-scales. - Abstract: Comparing with conventional physical vapor deposition methods, electrochemistry deposition technique shows a crack suppression effect by which the thickness of CeO2 films on Ni–5 at.%W substrate can reach a high value up to 200 nm without any cracks, make it a potential single buffer layer for coated conductor. In the present work, the processes of CeO2 film deposited by electrochemistry method are detailed investigated. A hydroxide reactive mechanism and an oxide reactive mechanism are distinguished for dimethyl sulfoxide and aqueous solution, respectively. Before heat treatment to achieve the required bi-axial texture performance of buffer layers, the precursor CeO2 films are identified in nanometer scales. The crack suppression for electrochemistry deposited CeO2 films is believed to be attributed to the nano-effects of the precursors

  20. 2D Cross Sectional Analysis and Associated Electrochemistry of Composite Electrodes Containing Dispersed Agglomerates of Nanocrystalline Magnetite, Fe₃O₄.

    Science.gov (United States)

    Bock, David C; Kirshenbaum, Kevin C; Wang, Jiajun; Zhang, Wei; Wang, Feng; Wang, Jun; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

    2015-06-24

    When electroactive nanomaterials are fully incorporated into an electrode structure, characterization of the crystallite sizes, agglomerate sizes, and dispersion of the electroactive materials can lend insight into the complex electrochemistry associated with composite electrodes. In this study, composite magnetite electrodes were sectioned using ultramicrotome techniques, which facilitated the direct observation of crystallites and agglomerates of magnetite (Fe3O4) as well as their dispersal patterns in large representative sections of electrode, via 2D cross sectional analysis by Transmission Electron Microscopy (TEM). Further, the electrochemistry of these electrodes were recorded, and Transmission X-ray Microscopy (TXM) was used to determine the distribution of oxidation states of the reduced magnetite. Unexpectedly, while two crystallite sizes of magnetite were employed in the production of the composite electrodes, the magnetite agglomerate sizes and degrees of dispersion in the two composite electrodes were similar to each other. This observation illustrates the necessity for careful characterization of composite electrodes, in order to understand the effects of crystallite size, agglomerate size, and level of dispersion on electrochemistry. PMID:26024206

  1. Applied superconductivity

    CERN Document Server

    Newhouse, Vernon L

    1975-01-01

    Applied Superconductivity, Volume II, is part of a two-volume series on applied superconductivity. The first volume dealt with electronic applications and radiation detection, and contains a chapter on liquid helium refrigeration. The present volume discusses magnets, electromechanical applications, accelerators, and microwave and rf devices. The book opens with a chapter on high-field superconducting magnets, covering applications and magnet design. Subsequent chapters discuss superconductive machinery such as superconductive bearings and motors; rf superconducting devices; and future prospec

  2. Applied Stratigraphy

    Science.gov (United States)

    Lucas, Spencer G.

    Stratigraphy is a cornerstone of the Earth sciences. The study of layered rocks, especially their age determination and correlation, which are integral parts of stratigraphy, are key to fields as diverse as geoarchaeology and tectonics. In the Anglophile history of geology, in the early 1800s, the untutored English surveyor William Smith was the first practical stratigrapher, constructing a geological map of England based on his own applied stratigraphy. Smith has, thus, been seen as the first “industrial stratigrapher,” and practical applications of stratigraphy have since been essential to most of the extractive industries from mining to petroleum. Indeed, gasoline is in your automobile because of a tremendous use of applied stratigraphy in oil exploration, especially during the latter half of the twentieth century. Applied stratigraphy, thus, is a subject of broad interest to Earth scientists.

  3. Applied mathematics

    CERN Document Server

    Logan, J David

    2013-01-01

    Praise for the Third Edition"Future mathematicians, scientists, and engineers should find the book to be an excellent introductory text for coursework or self-study as well as worth its shelf space for reference." -MAA Reviews Applied Mathematics, Fourth Edition is a thoroughly updated and revised edition on the applications of modeling and analyzing natural, social, and technological processes. The book covers a wide range of key topics in mathematical methods and modeling and highlights the connections between mathematics and the applied and nat

  4. Water as a promoter and catalyst for dioxygen electrochemistry in aqueous and organic media.

    Energy Technology Data Exchange (ETDEWEB)

    Staszak-Jirkovsky, Jakub; Subbaraman, Ram; Strmcnik, Dusan; Harrison, Katherine L.; Diesendruck, Charles E.; Assary, Rajeev; Frank, Otakar; Kobr, Lukas; Wiberg, Gustav K.H; Genorio, Bostjan; Connell, Justin G.; Lopes, Pietro P.; Stamenkovic, Vojislav R.; Curtiss, Larry; Moore, Jeffrey S.; Zavadil, Kevin R.; Markovic, Nenad M.

    2015-11-01

    Water and oxygen electrochemistry lies at the heart of interfacial processes controlling energy transformations in fuel cells, electrolyzers, and batteries. Here, by comparing results for the ORR obtained in alkaline aqueous media to those obtained in ultradry organic electrolytes with known amounts of H2O added intentionally, we propose a new rationale in which water itself plays an important role in determining the reaction kinetics. This effect derives from the formation of HOad center dot center dot center dot H2O (aqueous solutions) and LiO2 center dot center dot center dot H2O (organic solvents) complexes that place water in a configurationally favorable position for proton transfer to weakly adsorbed intermediates. We also find that, even at low concentrations (<10 ppm), water acts simultaneously as a promoter and as a catalyst in the production of Li2O2, regenerating itself through a sequence of steps that include the formation and recombination of H+ and OH-. We conclude that, although the binding energy between metal surfaces and oxygen intermediates is an important descriptor in electrocatalysis, understanding the role of water as a proton-donor reactant may explain many anomalous features in electrocatalysis at metal-liquid interfaces.

  5. Actinide, lanthanide and fission product speciation and electrochemistry in high and low temperature ionic melts

    International Nuclear Information System (INIS)

    There is currently a great deal of research interest in the development of molten salt technology, both classical high temperature melts and low temperature ionic liquids, for the electrochemical separation of the actinides from spent nuclear fuel. We are interested in gaining a better understanding of actinide and key fission product speciation and electrochemical properties in a range of melts. Our studies in high temperature alkali metal melts (including LiCl and LiCl-KCl and CsCl-NaCl eutectics) have focussed on in-situ species of U, Th, Tc and Ru using X-ray absorption spectroscopy (XAS, both EXAFS and XANES) and electronic absorption spectroscopy (EAS). We report unusual actinide speciation in high temperature melts and an evaluation of the likelihood of Ru or Tc volatilization during plant operation. Our studies in lower temperature melts (ionic liquids) have focussed on salts containing tertiary alkyl group 15 cations and the bis(tri-fluor-methyl)sulfonyl)imide anion, melts which we have shown to have exceptionally wide electrochemical windows. We report Ln, Th, U and Np speciation (XAS, EAS and vibrational spectroscopy) and electrochemistry in these melts and relate the solution studies to crystallographic characterised benchmark species. (authors)

  6. Glucose oxidase-graphene-chitosan modified electrode for direct electrochemistry and glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Xinhuang; Wang, Jun; Wu, Hong; Aksay, Ilhan A.; Liu, Jun; Lin, Yuehe

    2009-11-01

    Direct electrochemistry of a glucose oxidase (GOD)/graphene/chitosan nanocomposite was studied. The immobilized enzyme retains its bioactivity, exhibits a surface confined, reversible two-proton and two-electron transfer reaction, and has good stability, activity and a fast heterogeneous electron transfer rate with the rate constant (ks) of 2.83 s-1. A much higher enzyme loading (1.12 × 10-9 mol/cm2) is obtained as compared to the bare glass carbon surface. This GOD/graphene/chitosan nanocomposite film can be used for sensitive detection of glucose. The biosensor exhibits a wider linearity range from 0.08 mM to 12 mM glucose with a detection limit of 0.02 mM and much higher sensitivity (37.93 μA mM-1 cm-2) as compared with other nanostructured supports. The excellent performance of the biosensor is attributed to large surface-to-volume ratio and high conductivity of graphene, and good biocompatibility of chitosan, which enhances the enzyme absorption and promotes direct electron transfer between redox enzymes and the surface of electrodes.

  7. Direct Electrochemistry of Hemoglobin at a Graphene Gold Nanoparticle Composite Film for Nitric Oxide Biosensing

    Directory of Open Access Journals (Sweden)

    Guang-Chao Zhao

    2013-06-01

    Full Text Available A simple two-step method was employed for preparing nano-sized gold nanoparticles-graphene composite to construct a GNPs-GR-SDS modified electrode. Hemoglobin (Hb was successfully immobilized on the surface of a basal plane graphite (BPG electrode through a simple dropping technique. Direct electrochemistry and electrocatalysis of the hemoglobin-modified electrode was investigated. The as-prepared composites showed an obvious promotion of the direct electro-transfer between hemoglobin and the electrode. A couple of well-defined and quasi-reversible Hb CV peaks can be observed in a phosphate buffer solution (pH 7.0. The separation of anodic and cathodic peak potentials is 81 mV, indicating a fast electron transfer reaction. The experimental results also clarified that the immobilized Hb retained its biological activity for the catalysis toward NO. The biosensor showed high sensitivity and fast response upon the addition of NO, under the conditions of pH 7.0, potential ‒0.82 V. The time to reach the stable-state current was less than 3 s, and the linear response range of NO was 0.72–7.92 μM, with a correlation coefficient of 0.9991.

  8. Direct electrochemistry and electrocatalysis of myoglobin immobilized on zirconia/multi-walled carbon nanotube nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Ruping; Deng, Minqiang; Cui, Sanguan; Chen, Hong [Department of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031 (China); Qiu, Jianding, E-mail: jdqiu@ncu.edu.cn [Department of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031 (China)

    2010-12-15

    Zirconia/multi-walled carbon nanotube (ZrO{sub 2}/MWCNT) nanocomposite was prepared by hydrothermal treatment of MWCNTs in ZrOCl{sub 2}.8H{sub 2}O aqueous solution. The morphology and structure of the synthesized ZrO{sub 2}/MWCNT nanocomposite were characterized by transmission electron microscopy and X-ray diffraction analysis. It was found that ZrO{sub 2} nanoparticles homogeneously distributed on the sidewall of MWCNTs. Myoglobin (Mb), as a model protein to investigate the nanocomposite, was immobilized on ZrO{sub 2}/MWCNT nanocomposite. Ultraviolet-visible spectroscopy and electrochemical measurements showed that the nanocomposite could retain the bioactivity of the immobilized Mb to a large extent. The Mb immobilized in the composite showed excellent direct electrochemistry and electrocatalytic activity to the reduction of hydrogen peroxide (H{sub 2}O{sub 2}). The linear response range of the biosensor to H{sub 2}O{sub 2} concentration was from 1.0 to 116.0 {mu}M with the limit of detection of 0.53 {mu}M (S/N = 3). The ZrO{sub 2}/MWCNT nanocomposite provided a good biocompatible matrix for protein immobilization and biosensors preparation.

  9. Immobilization, direct electrochemistry and electrocatalysis of hemoglobin on colloidal silver nanoparticles-chitosan film

    International Nuclear Information System (INIS)

    This paper reports on the fabrication and characterization of hemoglobin (Hb)-colloidal silver nanoparticles (CSNs)-chitosan film on the glassy carbon electrode and its application on electrochemical biosensing. CSNs could greatly enhance the electron transfer reactivity of Hb as a bridge. In the phosphate buffer solution with pH value of 7.0, Hb showed a pair of well-defined redox peaks with the formal potential (E0') of -0.325 V (vs. SCE). The immobilized Hb in the film maintained its biological activity, showing a surface-controlled process with the heterogeneous electron transfer rate constant (ks) of 1.83 s-1 and displayed the same features of a peroxidase in the electrocatalytic reduction of oxygen and hydrogen peroxide (H2O2). The linear range for the determination of H2O2 was from 0.75 μM to 0.216 mM with a detection limit of 0.5 μM (S/N = 3). Such a simple assemble method could offer a promising platform for further study on the direct electrochemistry of other redox proteins and the development of the third-generation electrochemical biosensors.

  10. Electrohydrodynamic jet printing and a preliminary electrochemistry test of graphene micro-scale electrodes

    Science.gov (United States)

    Wang, Dazhi; Zha, Wen; Feng, Li; Ma, Qian; Liu, Xianming; Yang, Ning; Xu, Zheng; Zhao, Xiaojun; Liang, Junsheng; Ren, Tongqun; Wang, Xiaodong

    2016-04-01

    This paper reports the use of electrohydrodynamic jet (E-jet) printing technique for producing a wide range of graphene micro-scale structures. Ethyl cellulose-dispersed graphene ink and Nafion-dispersed graphene ink were prepared and used for E-Jet printing. A glass slide and PDMS substrate were used for E-Jet printing of graphene ink. The E-jet printed graphene micro-scale structures using ethyl cellulose-dispersed graphene ink presented a feature of center arrayed graphene surrounded by the track of evaporated solution. However, the E-Jet printed graphene structures using Nafion-dispersed graphene ink exhibited uniform arranged features. It was observed that the resistivity of the graphene structures printed from the ethyl cellulose-dispersed graphene ink was much lower than that from the Nafion-dispersed graphene ink. In addition, the graphene micro-scale electrodes were E-Jet printed for preliminary electrochemical applications. The results showed that the graphene micro-scale electrodes had a distinct response for the lead ion. Furthermore, a Pt/graphene composite electrode was formed and an electrochemistry test was conducted. It was found that the Pt /graphene composite electrode had a more sensitive response compared with the pure Pt electrode for electrochemical sensing.

  11. Direct electrochemistry of hemoglobin entrapped in dextran film on carbon ionic liquid electrode

    Indian Academy of Sciences (India)

    Xiaoqing Li; Yan Wang; Xiaoying Sun; Tianrong Zhan; Wei Sun

    2010-03-01

    Direct electrochemistry of hemoglobin (Hb) entrapped in the dextran (De) film on the surface of a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) modified carbon paste electrode (CILE) has been investigated. UV-Vis and FT-IR spectroscopy showed that Hb retained its native structure in the De film. Scanning electron microscopy (SEM) indicated an uniform film was formed on the electrode surface. Cyclic voltammetric experiments indicated that the electron transfer efficiency between Hb and the electrode was greatly improved due to the presence of the De film and ionic liquid, which provided a biocompatible and higher conductive interface. A pair of well-defined and quasi-reversible redox peak was obtained with the anodic and cathodic peaks located at -0.195 V and -0.355 V in pH 7.0 phosphate buffer solution, respectively. The electrochemical parameters were calculated by investigating the relationship of the peak potential with the scan rate. The fabricated De/Hb/CILE showed good electrocatalytic ability to the reduction of H2O2 with the linear concentration range from 4.0 × 10-6 to 1.5 × 10-5 mol/L and the apparent Michaelis-Menten constant ($K_{M}^{\\text{app}}$) for the electrocatalytic reaction was calculated as 0.17 M.

  12. Detailed H2 and CO Electrochemistry for a MEA Model Fueled by Syngas

    KAUST Repository

    Lee, W. Y.

    2015-07-17

    © The Electrochemical Society. SOFCs can directly oxidize CO in addition to H2, which allows them to be coupled to a gasifier. Many membrane-electrode-assembly (MEA) models neglect CO electrochemistry due to sluggish kinetics and the water-gas-shift reaction, but CO oxidation may be important for high CO-content syngas. The 1D-MEA model presented here incorporates detailed mechanisms for both H2 and CO oxidation, individually fitted to experimental data. These mechanisms are then combined into a single model, which provides a good fit to experimental data for H2/CO mixtures. Furthermore, the model fits H2/CO data best when a single chargetransfer step in the H2 mechanism is assumed to be rate-limiting for all current densities. This differs from the result for H2/H2O mixtures, where H2 adsorption becomes rate-limiting at high current densities. These results indicate that CO oxidation cannot be neglected in MEA models running on CO-rich syngas, and that CO oxidation can alter the H2 oxidation mechanism.

  13. Combinatorial electrochemistry using metal nanoparticles: from proof-of-concept to practical realisation for bromide detection.

    Science.gov (United States)

    Sljukić, Biljana; Baron, Ronan; Salter, Chris; Crossley, Alison; Compton, Richard G

    2007-05-01

    Principles and practical application of combinatorial electrochemistry in search for new electroactive materials in electroanalysis have been explored. Nanoparticles of three different metals: silver, gold and palladium have been independently synthesized on the glassy carbon spherical powder surface by electroless deposition process and characterized using both spectroscopic and electrochemical techniques. These three materials were then combined together onto basal plane pyrolytic graphite electrode surface and the application of the combinatorial approach to find the electrode material for bromide detection as model target analyte was demonstrated. The component electroactive for bromide detection was next identified and it was found that silver nanoparticles were the active ones. A composite electrode based on silver nanoparticle modified glassy carbon powder and epoxy resin was then fabricated and it was found to allow accurate determination of bromide. The electroactivity for the bromide determination of the composite electrode was compared with that of a bulk silver electrode and it was shown that the composite electrode is very efficient with a comparable electroactivity with only a portion of precious metals being used for its construction. PMID:17416224

  14. Metallic nanoparticles deposited on carbon microspheres: novel materials for combinatorial electrochemistry and electroanalysis.

    Science.gov (United States)

    Baron, Ronan; Wildgoose, Gregory G; Compton, Richard G

    2009-04-01

    This review deals with the preparation of metallic nanoparticles on glassy carbon microspheres and the use of these new hybrid materials for combinatorial electrochemistry and electroanalysis. First, the preparation of gold, silver and palladium nanoparticles on glassy carbon microspheres by a simple electroless procedure is described. Then, different types of electrodes modified with glassy carbon microspheres are described. These are: (i) glassy carbon electrodes modified by a composite film of glassy carbon microspheres and multi-walled carbon nanotubes, (ii) basal plane pyrolylic graphite electrodes modified by the abrasive attachment of glassy carbon microspheres and (iii) carbon-epoxy composite electrodes loaded with glassy carbon microspheres. The three types of electrode architectures described consist of metallic nanoparticles embedded in a carbon matrix and each of the electrode macrodisc surfaces actually correspond to a random metallic nanoelectrode array. Carbon-epoxy composite electrodes have good characteristics for their use as practical sensors. Furthermore, the use of several kinds of metallic nanoparticles allows the construction of a multi-analyte electrode and the screening of electroactive materials by following a combinatorial approach. PMID:19437964

  15. The electrochemistry of zirconium in aqueous solutions at elevated temperatures and pressures

    Science.gov (United States)

    Chen, Yingzi; Urquidi-Macdonald, Mirna; Macdonald, Digby D.

    2006-01-01

    The electrochemistry of zirconium has been explored in borate buffer solution of pH = 6.94 at 250 °C with and without hydrogen by measuring the current, impedance, and capacitance as a function of potential. Data are interpreted in terms of modified point defect models (PDM) that recognize the existence of a thick oxide outer layer over a thin barrier layer. From thermodynamic analysis, it is postulated that a hydride barrier layer forms under PWR coolant conditions whereas an oxide barrier layer forms under BWR primary coolant conditions. Thus, the introduction of hydrogen into the solution lowers the corrosion potential of zirconium to the extent that the formation of ZrH 2 is predicted to be spontaneous rather than the ZrO 2. Mott-Schottky analysis shows that the passive film formed on zirconium is n-type, which is consistent with the PDM, corresponding to a preponderance of oxygen/hydrogen vacancies and/or zirconium interstitials in the barrier layer.

  16. Dispersion of Nanocrystalline Fe3O4 within Composite Electrodes: Insights on Battery-Related Electrochemistry.

    Science.gov (United States)

    Bock, David C; Pelliccione, Christopher J; Zhang, Wei; Wang, Jiajun; Knehr, K W; Wang, Jun; Wang, Feng; West, Alan C; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

    2016-05-11

    Aggregation of nanosized materials in composite lithium-ion-battery electrodes can be a significant factor influencing electrochemical behavior. In this study, aggregation was controlled in magnetite, Fe3O4, composite electrodes via oleic acid capping and subsequent dispersion in a carbon black matrix. A heat treatment process was effective in the removal of the oleic acid capping agent while preserving a high degree of Fe3O4 dispersion. Electrochemical testing showed that Fe3O4 dispersion is initially beneficial in delivering a higher functional capacity, in agreement with continuum model simulations. However, increased capacity fade upon extended cycling was observed for the dispersed Fe3O4 composites relative to the aggregated Fe3O4 composites. X-ray absorption spectroscopy measurements of electrodes post cycling indicated that the dispersed Fe3O4 electrodes are more oxidized in the discharged state, consistent with reduced reversibility compared with the aggregated sample. Higher charge-transfer resistance for the dispersed sample after cycling suggests increased surface-film formation on the dispersed, high-surface-area nanocrystalline Fe3O4 compared to the aggregated materials. This study provides insight into the specific effects of aggregation on electrochemistry through a multiscale view of mechanisms for magnetite composite electrodes. PMID:27096464

  17. Reduced Graphene Oxide Thin Film on Conductive Substrates by Bipolar Electrochemistry

    Science.gov (United States)

    Anis, Allagui; Mohammad, Ali Abdelkareem; Hussain, Alawadhi; Ahmed, S. Elwakil

    2016-01-01

    Recent years have shown an increased interest in developing manufacturing processes for graphene and its derivatives that consider the environmental impact and large scale cost-effectiveness. However, today’s most commonly used synthesis routes still suffer from their excessive use of harsh chemicals and/or the complexity and financial cost of the process. Furthermore, the subsequent transfer of the material onto a substrate makes the overall process even more intricate and time-consuming. Here we describe a single-step, single-cell preparation procedure of metal-supported reduced graphene oxide (rGO) using the principle of bipolar electrochemistry of graphite in deionized water. Under the effect of an electric field between two stainless steel feeder electrodes, grapheme layers at the anodic pole of the wireless graphite were oxidized into colloidal dispersion of GO, which migrated electrophoretically towards the anodic side of the cell, and deposited in the form of rGO (d(002) = 0.395 nm) by van der Waals forces. For substrates chemically more susceptible to the high anodic voltage, we show that the electrochemical setup can be adapted by placing the latter between the wireless graphite and the stainless steel feeder anode. This method is straightforward, inexpensive, environmentally-friendly, and could be easily scaled up for high yield and large area production of rGO thin films. PMID:26883173

  18. Parameter estimation of an electrochemistry-based lithium-ion battery model

    Science.gov (United States)

    Masoudi, Ramin; Uchida, Thomas; McPhee, John

    2015-09-01

    Parameters for an electrochemistry-based Lithium-ion battery model are estimated using the homotopy optimization approach. A high-fidelity model of the battery is presented based on chemical and electrical phenomena. Equations expressing the conservation of species and charge for the solid and electrolyte phases are combined with the kinetics of the electrodes to obtain a system of differential-algebraic equations (DAEs) governing the dynamic behavior of the battery. The presence of algebraic constraints in the governing dynamic equations makes the optimization problem challenging: a simulation is performed in each iteration of the optimization procedure to evaluate the objective function, and the initial conditions must be updated to satisfy the constraints as the parameter values change. The ε-embedding method is employed to convert the original DAEs into a singularly perturbed system of ordinary differential equations, which are then used to simulate the system efficiently. The proposed numerical procedure demonstrates excellent performance in the estimation of parameters for the Lithium-ion battery model, compared to direct methods that are either unstable or incapable of converging. The obtained results and estimated parameters demonstrate the efficacy of the proposed simulation approach and homotopy optimization procedure.

  19. Reduced Graphene Oxide Thin Film on Conductive Substrates by Bipolar Electrochemistry

    Science.gov (United States)

    Anis, Allagui; Mohammad, Ali Abdelkareem; Hussain, Alawadhi; Ahmed, S. Elwakil

    2016-02-01

    Recent years have shown an increased interest in developing manufacturing processes for graphene and its derivatives that consider the environmental impact and large scale cost-effectiveness. However, today’s most commonly used synthesis routes still suffer from their excessive use of harsh chemicals and/or the complexity and financial cost of the process. Furthermore, the subsequent transfer of the material onto a substrate makes the overall process even more intricate and time-consuming. Here we describe a single-step, single-cell preparation procedure of metal-supported reduced graphene oxide (rGO) using the principle of bipolar electrochemistry of graphite in deionized water. Under the effect of an electric field between two stainless steel feeder electrodes, grapheme layers at the anodic pole of the wireless graphite were oxidized into colloidal dispersion of GO, which migrated electrophoretically towards the anodic side of the cell, and deposited in the form of rGO (d(002) = 0.395 nm) by van der Waals forces. For substrates chemically more susceptible to the high anodic voltage, we show that the electrochemical setup can be adapted by placing the latter between the wireless graphite and the stainless steel feeder anode. This method is straightforward, inexpensive, environmentally-friendly, and could be easily scaled up for high yield and large area production of rGO thin films.

  20. Electrochemistry of surface wired cytochrome c and bioelectrocatalytic sensing of superoxide

    Indian Academy of Sciences (India)

    Susmita Behera; Ramendra Sundar Dey; Manas Kumar Rana; C Retna Raj

    2013-03-01

    Electrochemistry of cytochrome c (Cyt-c) wired on an electrode modified with the self-assemblies of 4,4'-dithio-dibutyric acid (DTB) and 2-pyrazineethane thiol (PET) by covalent and electrostatic binding and the amperometric sensing of superoxide (O$^{−}_{2}$) are described. Cyt-c wired on the mixed self-assembly of DTB and PET displays well-defined voltammetric response at 0.025V with a peak-to-peak separation ( ) of 5mV. Pyrazine unit in the mixed self-assembly promotes the electron transfer in the redox reaction of surface wired Cyt-c. Cyt-c wired on the mixed self-assembly has been used for the amperometric sensing of superoxide. The enzymatically generated superoxide has been successfully detected using the Cyt-c wired electrode. High sensitivity and fast response for superoxide have been achieved. Uric acid does not interfere in the amperometric measurement of superoxide. The interference due to H2O2 has been eliminated by using enzyme catalase.

  1. Applied mineralogy

    Energy Technology Data Exchange (ETDEWEB)

    Park, W.C.; Hausen, D.M.; Hagni, R.D. (eds.)

    1985-01-01

    A conference on applied mineralogy was held and figures were presented under the following headings: methodology (including image analysis); ore genesis; exploration; beneficiations (including precious metals); process mineralogy - low and high temperatures; and medical science applications. Two papers have been abstracted separately.

  2. Applied dynamics

    CERN Document Server

    Schiehlen, Werner

    2014-01-01

    Applied Dynamics is an important branch of engineering mechanics widely applied to mechanical and automotive engineering, aerospace and biomechanics as well as control engineering and mechatronics. The computational methods presented are based on common fundamentals. For this purpose analytical mechanics turns out to be very useful where D’Alembert’s principle in the Lagrangian formulation proves to be most efficient. The method of multibody systems, finite element systems and continuous systems are treated consistently. Thus, students get a much better understanding of dynamical phenomena, and engineers in design and development departments using computer codes may check the results more easily by choosing models of different complexity for vibration and stress analysis.

  3. Applied optics

    International Nuclear Information System (INIS)

    The 1988 progress report, of the Applied Optics laboratory, of the (Polytechnic School, France), is presented. The optical fiber activities are focused on the development of an optical gyrometer, containing a resonance cavity. The following domains are included, in the research program: the infrared laser physics, the laser sources, the semiconductor physics, the multiple-photon ionization and the nonlinear optics. Investigations on the biomedical, the biological and biophysical domains are carried out. The published papers and the congress communications are listed

  4. Electrochemistry and electrocatalysis of a Pt@poly(neutral red) hybrid nanocomposite

    International Nuclear Information System (INIS)

    Highlights: • Pt nanoparticles are electrodeposited on poly(neutral red) film • Composite was studied by Vis-NIR spectroelectrogravimetry and ac-electrogravimetry • Pt stabilizes polarons of inter-monomer bonds of film • Polarons are the electrocatalytic sites • Poly(neutral red) acts as a proton and electron reservoir for H2O2 reduction. -- Abstract: Platinum nanoparticles have been deposited on a scaffold of electrosynthetized phenazine-type polymer, the poly(neutral red). This work discusses the role of poly(neutral red) in the electrochemistry and electrocatalysis properties of the hybrid nanocomposite. In situ combination of electrochemical quartz crystal microbalance and visible-near infrared spectroscopy (cyclic Vis-NIR spectroelectrogravimetry) and a combination of electrochemical impedance spectroscopy and mass impedance spectroscopy (ac-electrogravimetry) were employed. Two electrochemical processes have been identified in our experimental conditions. On the one hand, the radical cations (polarons) localized in the inter-monomer bonds of poly(neutral red) are identities stabilized by platinum nanoparticles. The polaron charge is balanced by the relative slow transfer of anions between the hybrid nanocomposite and solution. On the other hand, a relative fast transfer of cation (but not H3O+) is involved in the second electrochemical process. H2O2 was used as the target analyteto study the electrocatalytic reaction. The hybrid nanocomposite catalyzes the H2O2 reduction in phosphate buffer solutions at neutral pH. Polarons have been identified as the electrocatalytic sites. Poly(neutral red) would act as a proton reservoir used during the H2O2 reduction. The excellent electrocatalytic response and the knowledge of its electrochemical mechanism can help to developbiosensors for other analytes which react with radical species

  5. Electrochemistry of Iodide, Iodine, and Iodine Monochloride in Chloride Containing Nonhaloaluminate Ionic Liquids.

    Science.gov (United States)

    Bentley, Cameron L; Bond, Alan M; Hollenkamp, Anthony F; Mahon, Peter J; Zhang, Jie

    2016-02-01

    The electrochemical behavior of iodine remains a contemporary research interest due to the integral role of the I(-)/I3(-) couple in dye-sensitized solar cell technology. The neutral (I2) and positive (I(+)) oxidation states of iodine are known to be strongly electrophilic, and thus the I(-)/I2/I(+) redox processes are sensitive to the presence of nucleophilic chloride or bromide, which are both commonly present as impurities in nonhaloaluminate room temperature ionic liquids (ILs). In this study, the electrochemistry of I(-), I2, and ICl has been investigated by cyclic voltammetry at a platinum macrodisk electrode in a binary IL mixture composed of 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C2mim][NTf2]). In the absence of chloride (e.g., in neat [C2mim][NTf2]), I(-) is oxidized in an overall one electron per iodide ion process to I2 via an I3(-) intermediate, giving rise to two resolved I(-)/I3(-) and I3(-)/I2 processes, as per previous reports. In the presence of low concentrations of chloride ([Cl(-)] and [I(-)] are both complex anion [ICl2](-), in an overall two electron per iodide ion process. In the presence of a large excess of Cl(-) ([I(-)] ≈ 10 mM and [Cl(-)] ≈ 3.7 M), I(-) is oxidized in an overall two electron per iodide ion process to [ICl2](-) via an [I2Cl](-) intermediate (confirmed by investigating the voltammetric response of ICl and I2 under these conditions). In summary, the I(-)/I2/I(+) processes in nonhaloaluminate ILs involve a complicated interplay between multiple electron transfer pathways and homogeneous chemical reactions which may not be at equilibrium on the voltammetric time scale. PMID:26708364

  6. Direct electrochemistry and electrocatalysis of hemoglobin in graphene oxide and ionic liquid composite film

    International Nuclear Information System (INIS)

    In this paper a novel sensing platform based on graphene oxide (GO), ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate and Nafion for the immobilization of hemoglobin (Hb) was adopted with a carbon ionic liquid electrode (CILE) as the substrate electrode, which was denoted as Nafion/Hb–GO–IL/CILE. Spectroscopic results suggested that Hb molecules were not denatured in the composite. A pair of well-defined redox peaks appeared on the cyclic voltammogram, which was attributed to the realization of direct electron transfer of Hb on the electrode. Electrochemical behaviors of Hb entrapped in the film were carefully investigated by cyclic voltammetry with the electrochemical parameters calculated. Based on the catalytic ability of the immobilized Hb, Nafion/Hb–GO–IL/CILE exhibited excellent electrocatalytic behavior towards the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.01 to 40.0 mM with the detection limit as 3.12 μM (3σ), H2O2 in the concentration range from 0.08 to 635.0 μM with the detection limit as 0.0137 μM (3σ) and NaNO2 in the concentration range from 0.5 to 800.0 μM with the detection limit as 0.0104 μM (3σ). So the proposed bioelectrode could be served as a new third-generation electrochemical sensor without mediator. - Highlights: • A graphene oxide, 1-ethyl-3-methylimidazolium tetrafluoroborate and hemoglobin composite were prepared. • Composite modified carbon ionic liquid electrode was fabricated. • Direct electrochemistry of hemoglobin was realized on the modified electrode. • Bioelectrocatalytic reduction of the modified electrode to different substrates was studied

  7. Direct electrochemistry and electrocatalysis of hemoglobin in graphene oxide and ionic liquid composite film

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei, E-mail: swyy26@hotmail.com [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); Gong, Shixing [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Shi, Fan [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); Cao, Lili; Ling, Luyang [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zheng, Weizhe; Wang, Wencheng [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China)

    2014-07-01

    In this paper a novel sensing platform based on graphene oxide (GO), ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate and Nafion for the immobilization of hemoglobin (Hb) was adopted with a carbon ionic liquid electrode (CILE) as the substrate electrode, which was denoted as Nafion/Hb–GO–IL/CILE. Spectroscopic results suggested that Hb molecules were not denatured in the composite. A pair of well-defined redox peaks appeared on the cyclic voltammogram, which was attributed to the realization of direct electron transfer of Hb on the electrode. Electrochemical behaviors of Hb entrapped in the film were carefully investigated by cyclic voltammetry with the electrochemical parameters calculated. Based on the catalytic ability of the immobilized Hb, Nafion/Hb–GO–IL/CILE exhibited excellent electrocatalytic behavior towards the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.01 to 40.0 mM with the detection limit as 3.12 μM (3σ), H{sub 2}O{sub 2} in the concentration range from 0.08 to 635.0 μM with the detection limit as 0.0137 μM (3σ) and NaNO{sub 2} in the concentration range from 0.5 to 800.0 μM with the detection limit as 0.0104 μM (3σ). So the proposed bioelectrode could be served as a new third-generation electrochemical sensor without mediator. - Highlights: • A graphene oxide, 1-ethyl-3-methylimidazolium tetrafluoroborate and hemoglobin composite were prepared. • Composite modified carbon ionic liquid electrode was fabricated. • Direct electrochemistry of hemoglobin was realized on the modified electrode. • Bioelectrocatalytic reduction of the modified electrode to different substrates was studied.

  8. Semiconductor electrochemistry of coal pyrite. Final technical report, September 1990--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    Osseo-Asare, K.; Wei, Dawei

    1996-01-01

    This project seeks to advance the fundamental understanding of the physico-chemical processes occurring at the pyrite/aqueous interface, in the context of coal cleaning, coal desulfurization, and acid mine drainage. Central to this research is the use of synthetic microsize particles of pyrite as model microelectrodes to investigate the semiconductor electrochemistry of pyrite. The research focuses on: (a) the synthesis of microsize particles of pyrite in aqueous solution at room temperature, (b) the formation of iron sulfide complex, the precursor of FeS or FeS{sub 2}, and (c) the relationship between the semiconductor properties of pyrite and its interfacial electrochemical behavior in the dissolution process. In Chapter 2, 3 and 4, a suitable protocol for preparing microsize particles of pyrite in aqueous solution is given, and the essential roles of the precursors elemental sulfur and ``FeS`` in pyrite formation are investigated. In Chapter 5, the formation of iron sulfide complex prior to the precipitation of FeS or FeS{sub 2} is investigated using a fast kinetics technique based on a stopped-flow spectrophotometer. The stoichiometry of the iron sulfide complex is determined, and the rate and formation constants are also evaluated. Chapter 6 provides a summary of the semiconductor properties of pyrite relevant to the present study. In Chapters 7 and 8, the effects of the semiconductor properties on pyrite dissolution are investigated experimentally and the mechanism of pyrite dissolution in acidic aqueous solution is examined. Finally, a summary of the conclusions from this study and suggestions for future research are presented in Chapter 9.

  9. Integrating bipolar electrochemistry and electrochemiluminescence imaging with microdroplets for chemical analysis.

    Science.gov (United States)

    Wu, Suozhu; Zhou, Zhenyu; Xu, Linru; Su, Bin; Fang, Qun

    2014-03-15

    Here we develop a microdroplet sensor based on bipolar electrochemistry and electrochemiluminescence (ECL) imaging. The sensor was constructed with a closed bipolar cell on a hybrid poly(dimethylsioxane) (PDMS)-indium tin oxide (ITO) glass microchip. The ITO microband functions as the bipolar electrode and its two poles are placed in two spatially separate micro-reservoirs predrilled on the PDMS cover. After loading microliter-sized liquid droplets of tris(2,2'-bipyridyl) ruthenium (II)/2-(dibutylamino) ethanol (Ru(bpy)3(2+)/DBAE) and the analyte to the micro-reservoirs, an appropriate external voltage imposed on the driving electrodes could induce the oxidation of Ru(bpy)3(2+)/DBAE and simultaneous reduction of the analyte at the anodic and cathodic poles, respectively. ECL images generated by Ru(bpy)3(2+)/DBAE oxidation at the anodic pole and the electrical current flowing through the bipolar electrode can be recorded for quantitative analyte detection. Several types of quinones were selected as model analytes to demonstrate the sensor performance. Furthermore, the cathodic pole of bipolar electrode can be modified with (3-aminopropyl)triethoxysilane-gold nanoparticles-horseradish peroxidase composites for hydrogen peroxide detection. This microdroplet sensor with a closed bipolar cell can avoid the interference and cross-contamination between analyte solutions and ECL reporting reagents. It is also well adapted for chemical analysis in the incompatible system, e.g., detection of organic compounds insoluble in water by aqueous ECL generation. Moreover, this microdroplet sensor has advantages of simple structure, high sensitivity, fast response and wide dynamic response, providing great promise for chemical and biological analysis. PMID:24140829

  10. Direct Electrochemistry of Redox Proteins and Enzymes Promoted by Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Chenxin Cai

    2005-04-01

    Full Text Available The redox protein and enzyme, such as hemoglobin (Hb, horseradish peroxidase(HRP and glucose oxidase (GOx, was immobilized on the surface of the carbon nanotubemodified glassy carbon (CNT/GC electrode, respectively. The cyclic voltammetric resultsindicated that the redox protein and enzyme underwent effective and stable direct electrontransfer reaction with a pair of nearly symmetrical redox peaks. The formal redox potential,E0’, was almost independent on the scan rates, the average value of E0’ for Hb, HRP andGOx was –0.343 ± 0.001, –0.319 ± 0.002 and –0.456 ± 0.0008 V (vs. SCE,pH 6.9,respectively. The dependence of E0’ on the pH solution indicated that the direct electrontransfer of Hb and HRP was a one-electron-transfer reaction process coupled with oneproton-transfer, while the GOx was a two-electron-transfer coupled with two-protontransfer.The apparent heterogeneous electron transfer rate constant (ks was 1.25 ± 0.25,2.07 ± 0.69 and 1.74 ± 0.42 s-1 for Hb, HRP and GOx, respectively. The method presentedhere can be easily extended to immobilize other redox enzymes or proteins and obtain theirdirect electrochemistry.

  11. Endogenous minerals have influences on surface electrochemistry and ion exchange properties of biochar.

    Science.gov (United States)

    Zhao, Ling; Cao, Xinde; Zheng, Wei; Wang, Qun; Yang, Fan

    2015-10-01

    The feedstocks for biochar production are diverse and many of them contain various minerals in addition to being rich in carbon. Twelve types of biomass classified into 2 categories: plant-based and municipal waste, were employed to produce biochars under 350 °C and 500 °C. Their pH, point of zero net charge (PZNC), zeta potential, cation and anion exchange capacity (CEC and AEC) were analyzed. The municipal waste-based biochars (MW-BC) had higher mineral levels than the plant-based biochars (PB-BC). However, the water soluble mineral levels were lower in the MW-BCs due to the dominant presence of less soluble minerals, such as CaCO3 and (Ca,Mg)3(PO4)2. The higher total minerals in MW-BCs accounted for the higher PZNC (5.47-9.95) than in PB-BCs (1.91-8.18), though the PZNCs of the PB-BCs increased more than that of the MW-BCs as the production temperature rose. The minerals had influence on the zeta potentials via affecting the negative charges of biochars and the ionic strength of solution. The organic functional groups in PB-BCs such as -COOH and -OH had a greater effect on the CEC and AEC, while the minerals had a greater effect on that of MW-BCs. The measured CEC and AEC values had a strong positive correlation with the total amount of soluble cations and anions, respectively. Results indicated that biochar surface charges depend not only on the organic functional groups, but also on the minerals present and to some extent, minerals have more influences on the surface electrochemistry and ion exchange properties of biochar. PMID:25974107

  12. Electrochemistry, a technique to prepare redox nano-structured composite materials (polymer/nano-particles) - Characterizations - Applications

    International Nuclear Information System (INIS)

    In this work is presented at first the preparation by an electrochemical way of bi functional nano-structured composite materials. It is shown that with the pulsed electrolysis techniques, it is possible to obtain metallic particles whose size and organization are controlled at the nano-scopic scale in redox matrices. Then, are presented the physico-chemical characterizations of these nano-objects (coupled in situ or ex situ at the electrochemistry). The first results relative to the catalytic activation of CO2 with these materials used as composite cathodes are indicated. (O.M.)

  13. Applied geodesy

    International Nuclear Information System (INIS)

    This volume is based on the proceedings of the CERN Accelerator School's course on Applied Geodesy for Particle Accelerators held in April 1986. The purpose was to record and disseminate the knowledge gained in recent years on the geodesy of accelerators and other large systems. The latest methods for positioning equipment to sub-millimetric accuracy in deep underground tunnels several tens of kilometers long are described, as well as such sophisticated techniques as the Navstar Global Positioning System and the Terrameter. Automation of better known instruments such as the gyroscope and Distinvar is also treated along with the highly evolved treatment of components in a modern accelerator. Use of the methods described can be of great benefit in many areas of research and industrial geodesy such as surveying, nautical and aeronautical engineering, astronomical radio-interferometry, metrology of large components, deformation studies, etc

  14. Applied mathematics

    International Nuclear Information System (INIS)

    The 1988 progress report of the Applied Mathematics center (Polytechnic School, France), is presented. The research fields of the Center are the scientific calculus, the probabilities and statistics and the video image synthesis. The research topics developed are: the analysis of numerical methods, the mathematical analysis of the physics and mechanics fundamental models, the numerical solution of complex models related to the industrial problems, the stochastic calculus and the brownian movement, the stochastic partial differential equations, the identification of the adaptive filtering parameters, the discrete element systems, statistics, the stochastic control and the development, the image synthesis techniques for education and research programs. The published papers, the congress communications and the thesis are listed

  15. Applying radiation

    International Nuclear Information System (INIS)

    The invention discloses a method and apparatus for applying radiation by producing X-rays of a selected spectrum and intensity and directing them to a desired location. Radiant energy is directed from a laser onto a target to produce such X-rays at the target, which is so positioned adjacent to the desired location as to emit the X-rays toward the desired location; or such X-rays are produced in a region away from the desired location, and are channeled to the desired location. The radiant energy directing means may be shaped (as with bends; adjustable, if desired) to circumvent any obstruction between the laser and the target. Similarly, the X-ray channeling means may be shaped (as with fixed or adjustable bends) to circumvent any obstruction between the region where the X-rays are produced and the desired location. For producing a radiograph in a living organism the X-rays are provided in a short pulse to avoid any blurring of the radiograph from movement of or in the organism. For altering tissue in a living organism the selected spectrum and intensity are such as to affect substantially the tissue in a preselected volume without injuring nearby tissue. Typically, the selected spectrum comprises the range of about 0.1 to 100 keV, and the intensity is selected to provide about 100 to 1000 rads at the desired location. The X-rays may be produced by stimulated emission thereof, typically in a single direction

  16. Immobilization of horseradish peroxidase on self-assembled (3-mercaptopropyl)trimethoxysilane film: Characterization, direct electrochemistry, redox thermodynamics and biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Wu Fanghua [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials (Huaiyin Teachers College), Huaian 223300 (China); Hu Zhichao; Xu Jingjing [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Tian Yuan [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials (Huaiyin Teachers College), Huaian 223300 (China); Wang Liwei [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Xian Yuezhong [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials (Huaiyin Teachers College), Huaian 223300 (China)], E-mail: yzxian@chem.ecnu.edu.cn; Jin Litong [Department of Chemistry, East China Normal University, Shanghai 200062 (China)], E-mail: ltjin@chem.ecnu.edu.cn

    2008-11-30

    Highly organized (3-mercaptopropyl)trimethoxysilane (3-MPT) films have been prepared via self-assembled coupled with sol-gel linking technology. Horseradish peroxidase (HRP) is successfully immobilized onto the densely packed three-dimensional (3D) 3-MPT network and the direct electrochemistry of HRP is achieved without any electron mediators or promoters. Redox thermodynamics of HRP on the 3-MPT films, which is obtained from the temperature dependence of the reduction potential, suggests that the positive shift of redox potentials of HRP at the interface of 3-MPT originates from the solvent reorganization effects and conformational change of the polypeptide chain of HRP. Based on the direct electrochemistry and electrocatalytic ability of HRP, a sensitive third-generation amperometric H{sub 2}O{sub 2} biosensor is developed with two linear dependence ranges of 5.0 x 10{sup -7} to 1.0 x 10{sup -4} and 1.0 x 10{sup -4} to 2.0 x 10{sup -2} mol L{sup -1}.

  17. The direct electrochemistry of glucose oxidase based on the synergic effect of amino acid ionic liquid and carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Amino acid ionic liquids(AAILs) have attracted much attention due to their special chemical and physical properties,especially their outstanding biocompatibility and truly green aspect.In this work,a novel electrochemical biosensing platform based on AAILs/carbon nanotubes(CNTs) composite was fabricated.AAILs were used as a novel solvent for glucose oxidase(GOD) and the GOD-AAILs/CNTs/GC electrode was conveniently prepared by immersing the carbon nanotubes(CNTs) modified glassy carbon(GC) electrode into AAILs containing GOD.The direct electrochemistry of GOD on the GOD-AAILs/CNTs/GC electrode has been investigated and a pair of reversible peaks was obtained by cyclic voltammetry.The immobilized glucose oxidase could retain bioactivity and catalyze the reduction of dissolved oxygen.Due to the synergic effect of AAILs and CNTs,the GOD-AAILs/CNTs/GC electrode shows excellent electrocatalytic activity towards glucose with a linear range from 0.05 to 0.8 mM and a detection limit of 5.5 μM(S/N = 3).Furthermore,the biosensor exhibits good stability and ability to exclude the interference of commonly coexisting uric and ascorbic acid.Therefore,AAILs/CNTs composite can be a good candidate biocompatible material for the direct electrochemistry of the redox-active enzyme and the construction of third-generation enzyme sensors.

  18. The direct electrochemistry of glucose oxidase based on the synergic effect of amino acid ionic liquid and carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    WANG MengDong; DENG ChunYan; NIE Zhou; XU XiaHong; YAO ShouZhuo

    2009-01-01

    Amino acid ionic liquids (AAILs) have attracted much attention due to their special chemical and physical properties,especially their outstanding biocompatibility and truly green aspect.In this work,a novel electrochemical biosensing platform based on AAILs/carbon nanotubes (CNTs) composite was fabricated.AAILs were used as a novel solvent for glucose oxidase (GOD) and the GOD-AAILs/CNTs/GC electrode was conveniently prepared by immersing the carbon nanotubes (CNTs) modified glassy carbon (GC) electrode into AAILs containing GOD.The direct electrochemistry of GOD on the GOD-AAILs/CNTs/GC electrode has been investigated and a pair of reversible peaks was obtained by cyclic voltammetry.The immobilized glucose oxidase could retain bioactivity and catalyze the reduction of dissolved oxygen.Due to the synergic effect of AAILs and CNTs,the GOD-AAILs/CNTs/GC electrode shows excellent electrocatalytic activity towards glucose with a linear range from 0.05 to 0.8 mM and a detection limit of 5.5 μM (S/N=3).Furthermore,the biosensor exhibits good stability and ability to exclude the interference of commonly coexisting uric and ascorbic acid.Therefore,AAILs/CNTs composite can be a good candidate biocompatible material for the direct electrochemistry of the redox-active enzyme and the construction of third-generation enzyme sensors.

  19. Conceptual difficulties experienced by senior high school students of electrochemistry: Electric circuits and oxidation-reduction equations

    Science.gov (United States)

    Garnett, Pamela J.; Treagust, David F.

    The purpose of this research was to investigate students' understanding of electrochemistry following a course of instruction. A list of conceptual and propositional knowledge statements was formulated to identify the knowledge base necessary for students to understand electric circuits and oxidation-reduction equations. The conceptual and propositional knowledge statements provided the framework for the development of a semistructured interview protocol which was administered to 32 students in their final year of high school chemistry. The interview questions about electric circuits revealed that several students in the sample were confused about the nature of electric current both in metallic conductors and in electrolytes. Students studying both physics and chemistry were more confused about current flow in metallic conductors than students who were only studying chemistry. In the section of the interview which focused on oxidation and reduction, many students experienced problems in identifying oxidation-reduction equations. Several misconceptions relating to the inappropriate use of definitions of oxidation and reduction were identified. The data illustrate how students attempted to make sense of the concepts of electrochemistry with the knowledge they had already developed or constructed. The implications of the research are that teachers, curriculum developers, and textbook writers, if they are to minimize potential misconceptions, need to be cognizant of the relationship between physics and chemistry teaching, of the need to test for erroneous preconceptions about current before teaching about electrochemical (galvanic) and electrolytic cells, and of the difficulties experienced by students when using more than one model to explain scientific phenomena.

  20. Core-perfluoroalkylated perylene diimides and naphthalene diimides: versatile synthesis, solubility, electrochemistry, and optical properties.

    Science.gov (United States)

    Yuan, Zhongyi; Li, Jing; Xiao, Yi; Li, Zheng; Qian, Xuhong

    2010-05-01

    By a strategy featuring perfluoroalkylation of the highly soluble intermediates and their further efficient transformations to target compounds, a versatile synthesis of core-perfluoroalkylated perylene diimides (PDIs) and naphthalene diimides (NDIs) was developed, and PDIs perfluoroalkylated at 1-position or 1,6-positions and core-perfluoroalkylated NDIs were first obtained. By esterification, perfluoroalkylation, hydrolysis, and condensation with amine, 1-perfluorooctyl-PDIs (7b, 7c, and 7e), 1,7-bis(perfluorooctyl)-PDIs (8a-c and 8e-g), 1,6-bis(perfluorooctyl)-PDIs (8'e), a mixture of 1,7-bis(trifluoromethyl)-PDIs and 1,6-bis(trifluoromethyl)-PDIs (11b and 11'b, 11d and 11'd, in a ratio of 19:1), 2-perfluorooctyl-NDIs (20a-d), and 2,6-bis(perfluorooctyl)-NDIs (21a-21d) were efficiently synthesized. Five valuable intermediates--1-perfluorooctylperylene dianhydride (5), 1,7-bis(perfluorooctyl)perylene dianhydride (6) 1,6-bis(perfluorooctyl)perylene dianhydride (6'), 2-perfluorooctylnaphthalene dianhydride (18), and 2,6-bis(perfluorooctyl) naphthalene dianhydride (19)--were also obtained, and they can condense with many amines to produce PDIs containing different functional side chains on the imide nitrogen atoms. Solubility, electrochemistry, and optical properties of the above core-perfluoroalkylated PDIs and NDIs were investigated. Core-perfluoroalkylated 8e, 8f, 8'e, mixture of 11d and 11'd, 20b, and 20d with excellent solubility in common organic solvents are competitive as candidates as solution processable semiconductors. Core-perfluoroalkylated PDIs and NDIs with experimental LUMO energy of 4.04-4.34 eV demonstrate strong electron accepting ability. For core-perfluoroalkylated PDIs, the maximum absorptions display blue shifts of 6-18 nm and the maximum molar extinction coefficients decrease obviously relative to those of unsubstituted PDIs, and they inherit the strong fluorescence from the PDIs family, which makes them promising fluorescent dyes. PMID

  1. Electrochemistry of Chromium(0) – Aminocarbene Complexes. The use of intramolecular interaction LFER for characterization of the oxidation and reduction centre of the complex

    Czech Academy of Sciences Publication Activity Database

    Hoskovcová, I.; Roháčová, J.; Meca, L.; Tobrman, T.; Dvořák, D.; Ludvík, Jiří

    2005-01-01

    Roč. 50, - (2005), s. 4911-4915. ISSN 0013-4686 R&D Projects: GA ČR(CZ) GA203/04/0487 Institutional research plan: CEZ:AV0Z40400503 Keywords : electroreduction * electrooxidation * cyclic voltammetry Subject RIV: CG - Electrochemistry Impact factor: 2.453, year: 2005

  2. Conceptual Difficulties Experienced by Prospective Teachers in Electrochemistry: Half-Cell Potential, Cell Potential, and Chemical and Electrochemical Equilibrium in Galvanic Cells.

    Science.gov (United States)

    Ozkaya, Ali Riza

    2002-01-01

    A previous study of prospective teachers found that students from different countries and different levels of electrochemistry hold common misconceptions, indicating that concepts were presented to them poorly. Reports on how prospective teachers' scientifically incorrect ideas were used to form assertion-reason-type questions and how these…

  3. High Performance Liquid Chromatography-Electrochemistry-Electrospray Ionization Mass Spectrometry (HPLC/EC/ESI-MS) for Detection and Characterization of Roscovitine Oxidation Products

    Czech Academy of Sciences Publication Activity Database

    Karady, Michal; Novák, Ondřej; Horna, A.; Strnad, Miroslav; Doležal, Karel

    2011-01-01

    Roč. 23, č. 12 (2011), s. 2898-2905. ISSN 1040-0397 R&D Projects: GA MŠk ED0007/01/01; GA ČR GA301/08/1649 Keywords : Electrochemistry * Mass spectrometry * R-roscovitine Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.872, year: 2011

  4. Understanding the mechanism of direct electrochemistry of mitochondria-modified electrodes from yeast, potato and bovine sources at carbon paper electrodes

    International Nuclear Information System (INIS)

    Although mitochondria have been used for bio-electrochemistry for over 5 years, little is known about their direct electrochemistry mechanism. This paper focuses on developing a better understanding of the electron transfer mechanism of mitochondria from three different organisms at carbon electrodes. Yeast, potato and bovine mitochondria have been successfully isolated and immobilized onto Toray paper electrodes via vapor deposited silica. Organelle-modified electrodes were first characterized using cyclic voltammetry. Similar electrochemical signals were obtained for all organisms. Direct electron transfer was observed when a metabolite of the Krebs cycle was present in the buffer solution. Control experiments based on the immobilization of two electron carriers contained in mitochondria, cytochrome c and a quinone (coenzyme Q10), tend to show the electron transfer mechanism to the carbon material comes from the quinone pool of the organelles. As quinones are known to be pH-dependent, we further investigated the response of the electrochemical signal of the three isolated mitochondria and the two electron carriers separately. The half wave potentials obtained from the organelles appeared to be pH-dependent and their variations are comparable to coenzyme Q10 rather than cytochrome c. Finally, extraction of both the cytochrome c and the quinone pool from intact mitochondria was performed to validate our hypothesis that direct electrochemistry of mitochondria happens via the quinone pool. Electrochemistry of immobilized quinone-depleted mitochondria validated the hypothesis that the mitochondria are communicating with the electrodes through the quinone pool

  5. High Performance Liquid Chromatography/Electrochemistry/High Resolution Electrospray Ionization-Mass Spectrometry (HPLC/EC/HR ESI-MS) Characterization of Selected Cytokinins Oxidation Products

    Czech Academy of Sciences Publication Activity Database

    Karady, Michal; Novák, Ondřej; Horna, A.; Strnad, Miroslav; Doležal, Karel

    2015-01-01

    Roč. 27, č. 2 (2015), s. 406-414. ISSN 1040-0397 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Electrochemistry * Cytokinin * Oxidative metabolism Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.138, year: 2014

  6. Stereoisomeric products of electrochemical reduction of heterocyclic Fischer aminocarbene Cr(0) complexes. Development of the electrochemistry-mass spectrometry tandem approach using biphasic (acetonitrile-hexane) preparative electrolysis

    Czech Academy of Sciences Publication Activity Database

    Metelková, R.; Hoskovcová, I.; Polášek, Miroslav; Urban, Jiří; David, T.; Ludvík, Jiří

    2015-01-01

    Roč. 162, APR 2015 (2015), s. 17-23. ISSN 0013-4686 R&D Projects: GA ČR GAP206/11/0727 Institutional support: RVO:61388955 Keywords : Fischer aminocarbene complexes biphasic electrolysis * EC-MS * HPLC-NMR Subject RIV: CG - Electrochemistry Impact factor: 4.504, year: 2014

  7. Guiding Principles of Hydrogenase Catalysis Instigated and Clarified by Protein Film Electrochemistry.

    Science.gov (United States)

    Armstrong, Fraser A; Evans, Rhiannon M; Hexter, Suzannah V; Murphy, Bonnie J; Roessler, Maxie M; Wulff, Philip

    2016-05-17

    Protein film electrochemistry (PFE) is providing cutting-edge insight into the chemical principles underpinning biological hydrogen. Attached to an electrode, many enzymes exhibit "reversible" electrocatalytic behavior, meaning that a catalyzed redox reaction appears reversible or quasi-reversible when viewed by cyclic voltammetry. This efficiency is most relevant for enzymes that are inspiring advances in renewable energy, such as hydrogen-activating and CO2-reducing enzymes. Exploiting the rich repertoire of available instrumental methods, PFE experiments yield both a general snapshot and fine detail, all from tiny samples of enzyme. The dynamic electrochemical investigations blaze new trails and add exquisite detail to the information gained from structural and spectroscopic studies. This Account describes recent investigations of hydrogenases carried out in Oxford, including ideas initiated with PFE and followed through with complementary techniques, all contributing to an eventual complete picture of fast and efficient H2 activation without Pt. By immobilization of an enzyme on an electrode, catalytic electron flow and the chemistry controlling it can be addressed at the touch of a button. The buried nature of the active site means that structures that have been determined by crystallography or spectroscopy are likely to be protected, retained, and fully relevant in a PFE experiment. An electrocatalysis model formulated for the PFE of immobilized enzymes predicts interesting behavior and gives insight into why some hydrogenases are H2 producers and others are H2 oxidizers. Immobilization also allows for easy addition and removal of inhibitors along with precise potential control, one interesting outcome being that formaldehyde forms a reversible complex with reduced [FeFe]-hydrogenases, thereby providing insight into the order of electron and proton transfers. Experiments on O2-tolerant [NiFe]-hydrogenases show that O2 behaves like a reversible inhibitor: it

  8. Achieving direct electrochemistry of glucose oxidase by one step electrochemical reduction of graphene oxide and its use in glucose sensing.

    Science.gov (United States)

    Shamsipur, Mojtaba; Tabrizi, Mahmoud Amouzadeh

    2014-12-01

    In this paper, the direct electrochemistry of glucose oxidase (GOD) was accomplished at a glassy carbon electrode modified with electrochemically reduced graphene oxide/sodium dodecyl sulfate (GCE/ERGO/SDS). A pair of reversible peaks is exhibited on GCE/ERGO/SDS/GOD by cyclic voltammetry. The peak-to-peak potential separation of immobilized GOD is 28 mV in 0.1 M phosphate buffer solution (pH7.0) with a scan rate of 50 mV/s. The average surface coverage is 2.62×10(-10) mol cm(-2). The resulting biosensor exhibited a good response to glucose with linear range from 1 to 8 mM (R(2)=0.9878), good reproducibility and detection limit of 40.8 μM. The results from the biosensor were similar (±5%) to those obtained from the clinical analyzer. PMID:25491807

  9. In situ STM imaging and direct electrochemistry of Pyrococcus furiosus ferredoxin assembled on thiolate-modified Au(111) surfaces

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Christensen, Hans Erik Mølager; Ooi, Bee Lean;

    2004-01-01

    surface microscopic structures of PfFd monolayers, as revealed by scanning tunneling microscopy under potential control (in situ STM). Direct ET between PfFd in phosphate buffer solution, pH 7.9, and EPG electrodes is observed in the presence of promoters. Neomycin gives rise to a pair of redox peaks with...... electrode surface modified by the same functional group monolayer and to address diffusionless direct electrochemistry, as well as surface microstructures of the protein monolayer. PfFd molecules were found to assemble on either mercaptopropionic acid (MPA) or cysteine-modified Au(111) surfaces in stable...... monolayers or submonolayers. Highly ordered (2root3 x 5)R30degrees cluster structures with six MPA molecules in each cluster were found by in situ STM. Individual PfFd molecules on the MPA layer are well resolved by in situ STM. Under Ar protection reversible cyclic voltammograms were obtained on Pf...

  10. Combined optical and electrochemical methods for studying electrochemistry at the single molecule and single particle level: recent progress and perspectives.

    Science.gov (United States)

    Hill, Caleb M; Clayton, Daniel A; Pan, Shanlin

    2013-12-28

    We present a review of recent efforts aimed at understanding interfacial charge transfer at the single molecule and single nanoparticle level using the combined methods of traditional electrochemistry and optical spectroscopy with high spatial, spectral, and temporal resolution. Elastic light scattering, surface enhanced Raman scattering (SERS), fluorescence, and electrogenerated chemiluminescence (ECL) techniques have been demonstrated to be powerful tools for the study of interfacial charge transfer events involving a single molecule or nanoparticle and for the characterization of nanostructured electrodes. It is shown that these optical methods enable the exploration of electrochemical events with improved temporal and spatial resolution which are usually obstructed by the ensemble averaging inherent in conventional electrochemical methods. In this report, the current status of the field is reviewed and challenges for future work are discussed. PMID:24196825

  11. A história, evolução e crescimento da Eletroquímica: Eletroanalítica nestes últimos 25 anos The history, evolution and growth of Electrochemistry: Electroanalytical chemistry in the past 25 years

    OpenAIRE

    Luis Alberto Avaca; Roberto Tokoro

    2002-01-01

    This text describes the development of Electrochemistry and Electroanalytical Chemistry in Brazil from the pioneers at the IQ/USP in the 70's to the present day status. It explains how the members of the scientific community organized themselves before the establishment in 1993 of a specific division within the Brazilian Chemical Society (SBQ) through bi-ennial meetings (Brazilian Symposium of Electrochemistry and Electroanalytical Chemistry - SIBEE). Those SIBEE meetings, in a present number...

  12. Experimental and theoretical study of possible correlation between the electrochemistry of canthin-6-one and the anti-proliferative activity against human cancer stem cells

    Science.gov (United States)

    Cebrián-Torrejón, G.; Doménech-Carbó, A.; Scotti, M. T.; Fournet, A.; Figadère, B.; Poupon, E.

    2015-12-01

    This work presents an approach to study the performance of novel targets able to overcome cancer stem cell chemoresistance, based on the voltammetric data for microparticulate films of natural or synthetic alkaloids from the canthin-6-one series. A comparison of this voltammetric technique with conventional solution phase electrochemistry suggests the differences in the anti-proliferative activity of canthin-6-ones could be tentatively correlated to their different capacity to generate semiquinone radical anions. These data also match theoretical calculations.

  13. 99Tc and Re incorporated into metal oxide polyoxometalates: oxidation state stability elucidated by electrochemistry and theory.

    Science.gov (United States)

    McGregor, Donna; Burton-Pye, Benjamin P; Mbomekalle, Israel M; Aparicio, Pablo A; Romo, Susanna; López, Xavier; Poblet, Josep M; Francesconi, Lynn C

    2012-08-20

    The radioactive element technetium-99 ((99)Tc, half-life = 2.1 × 10(5) years, β(-) of 253 keV), is a major byproduct of (235)U fission in the nuclear fuel cycle. (99)Tc is also found in radioactive waste tanks and in the environment at National Lab sites and fuel reprocessing centers. Separation and storage of the long-lived (99)Tc in an appropriate and stable waste-form is an important issue that needs to be addressed. Considering metal oxide solid-state materials as potential storage matrixes for Tc, we are examining the redox speciation of Tc on the molecular level using polyoxometalates (POMs) as models. In this study we investigate the electrochemistry of Tc complexes of the monovacant Wells-Dawson isomers, α(1)-P(2)W(17)O(61)(10-) (α1) and α(2)-P(2)W(17)O(61)(10-) (α2) to identify features of metal oxide materials that can stabilize the immobile Tc(IV) oxidation state accessed from the synthesized Tc(V)O species and to interrogate other possible oxidation states available to Tc within these materials. The experimental results are consistent with density functional theory (DFT) calculations. Electrochemistry of K(7-n)H(n)[Tc(V)O(α(1)-P(2)W(17)O(61))] (Tc(V)O-α1), K(7-n)H(n)[Tc(V)O(α(2)-P(2)W(17)O(61))] (Tc(V)O-α2) and their rhenium analogues as a function of pH show that the Tc-containing derivatives are always more readily reduced than their Re analogues. Both Tc and Re are reduced more readily in the lacunary α1 site as compared to the α2 site. The DFT calculations elucidate that the highest oxidation state attainable for Re is VII while, under the same electrochemistry conditions, the highest oxidation state for Tc is VI. The M(V)→ M(IV) reduction processes for Tc(V)O-α1 are not pH dependent or only slightly pH dependent suggesting that protonation does not accompany reduction of this species unlike the M(V)O-α2 (M = (99)Tc, Re) and Re(V)O-α1 where M(V/IV) reduction process must occur hand in hand with protonation of the terminal M═O to

  14. Direct electrochemistry and electrocatalysis of horseradish peroxidase with hyaluronic acid-ionic liquid-cadmium sulfide nanorod composite material

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhihong [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Li Xia; Wang Yan [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zeng Yan [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Sun Wei, E-mail: sunwei@qust.edu.cn [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Huang Xintang [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China)

    2010-06-18

    A new composite material consisted of hyaluronic acid (HA), ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF{sub 4}) and cadmium sulfide (CdS) nanorod was fabricated and used for the immobilization of horseradish peroxidase (HRP) on the surface of a carbon ionic liquid electrode (CILE), which was prepared with 1-ethyl-3-methyl-imidazolium ethylsulphate ([EMIM]EtOSO{sub 3}) as modifier. Spectroscopic results indicated that HRP remained its native structure in the composite film. Based on the synergistic effect of the materials used, an obvious promotion to the direct electron transfer efficient between HRP and CILE was achieved with a pair of well-defined redox peaks appeared in 0.1 mol L{sup -1} phosphate buffer solution, indicating the realization of the direct electrochemistry of HRP. The immobilized HRP showed good electrocatalytic activity towards the reduction of trichloroacetic acid and H{sub 2}O{sub 2} with the electrochemical parameters calculated. Based on the fabricated electrode, a new third-generation electrochemical biosensor was constructed with good stability and reproducibility.

  15. Direct electrochemistry and electrocatalysis of horseradish peroxidase with hyaluronic acid-ionic liquid-cadmium sulfide nanorod composite material

    International Nuclear Information System (INIS)

    A new composite material consisted of hyaluronic acid (HA), ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) and cadmium sulfide (CdS) nanorod was fabricated and used for the immobilization of horseradish peroxidase (HRP) on the surface of a carbon ionic liquid electrode (CILE), which was prepared with 1-ethyl-3-methyl-imidazolium ethylsulphate ([EMIM]EtOSO3) as modifier. Spectroscopic results indicated that HRP remained its native structure in the composite film. Based on the synergistic effect of the materials used, an obvious promotion to the direct electron transfer efficient between HRP and CILE was achieved with a pair of well-defined redox peaks appeared in 0.1 mol L-1 phosphate buffer solution, indicating the realization of the direct electrochemistry of HRP. The immobilized HRP showed good electrocatalytic activity towards the reduction of trichloroacetic acid and H2O2 with the electrochemical parameters calculated. Based on the fabricated electrode, a new third-generation electrochemical biosensor was constructed with good stability and reproducibility.

  16. Direct electrochemistry of cytochrome c immobilized on titanium nitride/multi-walled carbon nanotube composite for amperometric nitrite biosensor.

    Science.gov (United States)

    Haldorai, Yuvaraj; Hwang, Seung-Kyu; Gopalan, Anantha-Iyengar; Huh, Yun Suk; Han, Young-Kyu; Voit, Walter; Sai-Anand, Gopalan; Lee, Kwang-Pill

    2016-05-15

    In this report, titanium nitride (TiN) nanoparticles decorated multi-walled carbon nanotube (MWCNTs) nanocomposite is fabricated via a two-step process. These two steps involve the decoration of titanium dioxide nanoparticles onto the MWCNTs surface and a subsequent thermal nitridation. Transmission electron microscopy shows that TiN nanoparticles with a mean diameter of ≤ 20 nm are homogeneously dispersed onto the MWCNTs surface. Direct electrochemistry and electrocatalysis of cytochrome c immobilized on the MWCNTs-TiN composite modified on a glassy carbon electrode for nitrite sensing are investigated. Under optimum conditions, the current response is linear to its concentration from 1 µM to 2000 µM with a sensitivity of 121.5 µA µM(-1)cm(-2) and a low detection limit of 0.0014 µM. The proposed electrode shows good reproducibility and long-term stability. The applicability of the as-prepared biosensor is validated by the successful detection of nitrite in tap and sea water samples. PMID:26748372

  17. Potassium-doped carbon nanotubes toward the direct electrochemistry of cholesterol oxidase and its application in highly sensitive cholesterol biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaorong [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Xu Jingjuan, E-mail: xujj@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Chen Hongyuan [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

    2011-10-30

    We demonstrate herein a newly developed serum total cholesterol biosensor by using the direct electron transfer of cholesterol oxidase (ChOx), which is based on the immobilization of cholesterol oxidase and cholesterol esterase (ChEt) on potassium-doped multi-walled carbon nanotubes (KMWNTs) modified electrodes. The KMWNTs accelerate the electron transfer from electrode surface to the immobilized ChOx, achieving the direct electrochemistry of ChOx and maintaining its bioactivity. As a new platform in cholesterol analysis, the resulting electrode (ChOx/KMWNTs/GCE) exhibits a sensitive response to free cholesterol, with a linear range of 0.050-16.0 {mu}mol L{sup -1} and a detection limit of 5.0 nmol L{sup -1} (S/N = 3). Coimmobilization of ChEt and ChOx (ChEt/ChOx/KMWNTs/GCE) allows the determination of both free cholesterol and esterified cholesterol. The resulting biosensor shows the same linear range of 0.050-16.0 {mu}mol L{sup -1} for free cholesterol and cholesteryl oleate, with the detection limit of 10.0 and 12.0 nmol L{sup -1} (S/N = 3), respectively. The concentrations of total (free and esterified) cholesterol in human serum samples, determined by using the techniques developed in the present study, are in good agreement with those determined by the well-established techniques using the spectrophotometry.

  18. Electrochemistry in aqueous solution at high temperature and under pressure: study of nickel in a highly alkaline environment

    International Nuclear Information System (INIS)

    This research thesis reports the study of the corrosion resistance and anodic behaviour of various metals and alloys used in conventional thermal or nuclear power stations, more particularly the case of nickel in a highly alkaline environment (KOH 5 N) which is widely used for hydrogen production by water electrolysis. The author studied the influence of temperature and pressure on the electrochemical behaviour of nickel, and more particularly the first-oxidation kinetics. The report discusses the physicochemical and thermodynamic properties of aqueous systems at high temperature and under pressure, presents the general techniques of high-temperature electrochemistry, describes the experimental installation, and reports the development of a reference electrode which can operate in those experimental conditions. The author reports the study of the electrochemical behaviour of nickel in alkaline environment and at high temperature, reports a surface analysis performed by Auger spectroscopy, electron spectroscopy for chemical analysis or ESCA, and scanning electronic microscopy, reports the study of the electrochemical behaviour of nickel in a potassium hydroxide solution under normal temperature and pressure, but also in acid environment. Results are interpreted with respect to temperature

  19. Forensic analyses of explosion debris from the January 2, 1992 Pd/D2O electrochemistry incident at SRI International

    International Nuclear Information System (INIS)

    The January 2, 1992 explosion in an electrochemistry laboratory at SRI International (SRI) resulted in the death of scientist Andrew Riley, and gained some notoriety due to its association with experimental work in the controversial field of cold fusion research. Selected components of explosion debris were subjected to forensic analyses at LLNL to elucidate potential causes of, or contributing factors to, the explosion. Interrogation of the debris by LLNL encompassed nuclear, chemical, physical, and materials investigations. Nuclear studies for the determination of tritium and neutron-activation products in stainless steel and brass were negative. No evidence of signature species indicative of orthodox nuclear events was detected. The inorganic and particulate analyses were likewise negative with respect to residues of unexpected chemical species. Such target compounds included conventional explosives, accelerants, propellants, or any exceptional industrial chemicals. The GC-MS analyses of trace organic components in the explosion debris provided perhaps the most interesting results obtained at LLNL. Although no evidence of organic explosives, oxidizers, or other unusual compounds was detected, the presence of a hydrocarbon oil in the interior of the electrochemical cell was established. It is likely that its source was lubricating fluid from the machining of the metal cell components. If residues of organic oils are present during electrolysis experiments, the potential exists for an explosive reaction in the increasingly enriched oxygen atmosphere within the headspace of a metal cell

  20. Lack of nano size effect on electrochemistry of dopamine at a gold nanoparticle modified indium tin oxide electrode

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Nanometer sized materials have been shown to possess excellent chemical and electrochemical catalytic properties.In this work,a gold nanoparticle (AuNP) modified indium tin oxide (ITO) electrode was employed for investigating its electro-catalytic property.AuNP was deposited on the 3-aminopropyltriethoxysilane (APTES) modified ITO electrode by self-assembly,and was characterized by scanning electron microscopy and cyclic voltammetry.Although the electrochemical reaction of dopamine was very sluggish on the ITO/APTES electrode,it was significantly enhanced after AuNP deposition.The cyclic voltammogram exhibited apparent dependence on the surface coverage of 11 nm AuNPs,which could be rationalized by different modes of mass diffusion.Among the different sizes of AuNP investigated,the lowest anodic peak potential was observed on 11 nm AuNP.However,the potential was still about 50 mV more positive than that obtained on a bulk gold electrode of similar geometry.It is therefore concluded that there is no nanometer size effect of AuNP modified ITO on the electrochemistry of dopamine.

  1. A quantitative assay for reductive metabolism of a pesticide in fish using electrochemistry coupled with liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Bussy, Ugo; Chung-Davidson, Yu-Wen; Li, Ke; Li, Weiming

    2015-04-01

    This is the first study to use electrochemistry to generate a nitro reduction metabolite as a standard for a liquid chromatography-mass spectrometry-based quantitative assay. This approach is further used to quantify 3-trifluoromethyl-4-nitrophenol (TFM) reductive metabolism. TFM is a widely used pesticide for the population control of sea lamprey (Petromyzon marinus), an invasive species of the Laurentian Great Lakes. Three animal models, sea lamprey, lake sturgeon (Acipenser fulvescens), and rainbow trout (Oncorhynchus mykiss), were selected to evaluate TFM reductive metabolism because they have been known to show differential susceptibilities to TFM toxicity. Amino-TFM (aTFM; 3-trifluoromethyl-4-aminophenol) was the only reductive metabolite identified through liquid chromatography-high-resolution mass spectrometry screening of liver extracts incubated with TFM and was targeted for electrochemical synthesis. After synthesis and purification, aTFM was used to develop a quantitative assay of the reductive metabolism of TFM through liquid chromatography and tandem mass spectrometry. The concentrations of aTFM were measured from TFM-treated cellular fractions, including cytosolic, nuclear, membrane, and mitochondrial protein extracts. Sea lamprey extracts produced the highest concentrations (500 ng/mL) of aTFM. In addition, sea lamprey and sturgeon cytosolic extracts showed concentrations of aTFM substantially higher than those of rainbow trout. However, other fractions of lake sturgeon extracts tend to show aTFM concentrations similar to those of rainbow trout but not with sea lamprey. These data suggest that the level of reductive metabolism of TFM may be associated with the sensitivities of the animals to this particular pesticide. PMID:25730707

  2. Sol–gel derived silica/chitosan/Fe3O4 nanocomposite for direct electrochemistry and hydrogen peroxide biosensing

    International Nuclear Information System (INIS)

    A novel strategy to fabricate hydrogen peroxide third generation biosensor has been developed from sol–gel of silica/chitosan (SC) organic–inorganic hybrid material assimilated with iron oxide magnetic nanoparticles (Fe3O4). The large surface area of Fe3O4 and porous morphology of the SC composite facilitates a high loading of horseradish peroxidase (HRP). Moreover, the entrapped enzyme preserves its conformation and biofunctionality. The fabrication of hydrogen peroxide biosensor has been carried out by drop casting of the SC/F/HRP nanocomposite on glassy carbon electrode (GCE) for study of direct electrochemistry. The x-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) confirms the phase purity and particle size of as-synthesized Fe3O4 nanoparticles, respectively. The nanocomposite was characterized by UV–vis spectroscopy, fluorescence spectroscopy and Fourier transform infrared (FTIR) for the characteristic structure and conformation of enzyme. The surface topographies of the nanocomposite thin films were investigated by scanning electron microscopy (SEM). Dynamic light scattering (DLS) was used to determine the particle size distribution. The electrostatic interactions of the SC composite with Fe3O4 nanoparticles were studied by the zeta potential measurement. Electrochemical impedance spectroscopy (EIS) of the SC/F/HRP/GCE electrode displays Fe3O4 nanoparticles as an excellent candidate for electron transfer. The SC/F/HRP/GCE exhibited a pair of well-defined quasi reversible cyclic voltammetry peaks due to the redox couple of HRP-heme Fe (III)/Fe (II) in pH 7.0 potassium phosphate buffer. The biosensor was employed to detect H2O2 with linear range of 5 μM to 40 μM and detection limit of 5 μM. The sensor displays excellent selectivity, sensitivity, good reproducibility and long term stability. (paper)

  3. Sol-gel derived silica/chitosan/Fe3O4 nanocomposite for direct electrochemistry and hydrogen peroxide biosensing

    Science.gov (United States)

    Satvekar, R. K.; Rohiwal, S. S.; Tiwari, A. P.; Raut, A. V.; Tiwale, B. M.; Pawar, S. H.

    2015-01-01

    A novel strategy to fabricate hydrogen peroxide third generation biosensor has been developed from sol-gel of silica/chitosan (SC) organic-inorganic hybrid material assimilated with iron oxide magnetic nanoparticles (Fe3O4). The large surface area of Fe3O4 and porous morphology of the SC composite facilitates a high loading of horseradish peroxidase (HRP). Moreover, the entrapped enzyme preserves its conformation and biofunctionality. The fabrication of hydrogen peroxide biosensor has been carried out by drop casting of the SC/F/HRP nanocomposite on glassy carbon electrode (GCE) for study of direct electrochemistry. The x-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) confirms the phase purity and particle size of as-synthesized Fe3O4 nanoparticles, respectively. The nanocomposite was characterized by UV-vis spectroscopy, fluorescence spectroscopy and Fourier transform infrared (FTIR) for the characteristic structure and conformation of enzyme. The surface topographies of the nanocomposite thin films were investigated by scanning electron microscopy (SEM). Dynamic light scattering (DLS) was used to determine the particle size distribution. The electrostatic interactions of the SC composite with Fe3O4 nanoparticles were studied by the zeta potential measurement. Electrochemical impedance spectroscopy (EIS) of the SC/F/HRP/GCE electrode displays Fe3O4 nanoparticles as an excellent candidate for electron transfer. The SC/F/HRP/GCE exhibited a pair of well-defined quasi reversible cyclic voltammetry peaks due to the redox couple of HRP-heme Fe (III)/Fe (II) in pH 7.0 potassium phosphate buffer. The biosensor was employed to detect H2O2 with linear range of 5 μM to 40 μM and detection limit of 5 μM. The sensor displays excellent selectivity, sensitivity, good reproducibility and long term stability.

  4. Advances in metal electrochemistry and coatings characterisation; Sviluppi nella elettrochimica dei metalli e nella caratterizzazione dei rivestimenti

    Energy Technology Data Exchange (ETDEWEB)

    Bozzini, B. [Lecce Univ. (Italy). Dipt. di Ingegneria dell' Innovazione; Giovannelli, G.; Magagnin, L.; Manara, D.; Negri, E.; Vallauri, R. [Politecnico di Milano, Milan (Italy). Dipt. di Chimica Fisica Applicata; Lecis, N. [Politecnico di Milano, Milan (Italy). Dipt. di Meccanica; Lenardi, C. [Commission of European Union, Joint Research Centre, Ispra, VA (Italy); Zangari, G. [Alabama Univ., AL (United States). Dept. of Metallurgical and Materials Engineering

    1999-08-01

    In the present paper recent results in the fields of metal electrochemistry and structural and functional characterisation of coatings are reported from laboratories co-ordinated by prof. Pietro Luigi Cavallotti. The reviewed material deals with: electrochemical and autocatalytic chemical deposition of material matrix particulate composites with ceramic dispersoids, simulation of nano indentation experiments using finite element method, giant magnetoresistance electrodeposited Cu/CoNi(Cu) multilayers, surface treatment for copper soldering in microelectronics, Co-Pt alloys for ultra-high density magnetic recording, electrodeposited Co-Pt thick layers for micro-magnets and hot corrosion resistance applications. Fundamental understanding of electro crystallization phenomena and perspective high-tech applications are stressed. Structural and functional properties of the electrodeposited materials are related to electrochemical kinetics data. [Italian] In questa raccolta di articoli sono presentati i risultati piu' recenti ottenuti nei campi dell'elettrochimica e della caratterizzazione funzionale e strutturale dei rivestimenti dai gruppi di ricerca coordinati dal prof. P.L. Cavallotti. Vengono qui rivisti argomenti quali: deposizione elettrochimica e chimica autocatalitica di materiali compositi con particelle ceramiche disperse in matrice metallico, simulazione di esperimenti di nanoindentazione applicando il metodo a elemento finito, multistrati elettrodepositati di Cu/CoNi(Cu) a magnetoresistenza gigante, trattamenti di superficie per saldatura di Cu nella microelettronica, leghe Co-Pt per registrazione magnetica ad alta densita', strati spessi di Co-Pt elettrodepositati per micromagneti e resistenza a corrosione ad alta temperatura. Sono evidenziate applicazioni ad alta tecnologia e la comprensione di base di fenomeni di elettrocristallizzazione . Proprita' strutturali e funzionali dei materialielettrodepositati sono messe in relazione con i

  5. Silver vanadium diphosphate Ag2VP2O8: Electrochemistry and characterization of reduced material providing mechanistic insights

    International Nuclear Information System (INIS)

    Silver vanadium phosphorous oxides (AgwVxPyOz) are notable battery cathode materials due to their high energy density and demonstrated ability to form in-situ Ag metal nanostructured electrically conductive networks within the cathode. While analogous silver vanadium diphosphate materials have been prepared, electrochemical evaluations of these diphosphate based materials have been limited. We report here the first electrochemical study of a silver vanadium diphosphate, Ag2VP2O8, where the structural differences associated with phosphorous oxides versus diphosphates profoundly affect the associated electrochemistry. Reminiscent of Ag2VO2PO4 reduction, in-situ formation of silver metal nanoparticles was observed with reduction of Ag2VP2O8. However, counter to Ag2VO2PO4 reduction, Ag2VP2O8 demonstrates a significant decrease in conductivity upon continued electrochemical reduction. Structural analysis contrasting the crystallography of the parent Ag2VP2O8 with that of the proposed Li2VP2O8 reduction product is employed to gain insight into the observed electrochemical reduction behavior, where the structural rigidity associated with the diphosphate anion may be associated with the observed particle fracturing upon deep electrochemical reduction. Further, the diphosphate anion structure may be associated with the high thermal stability of the partially reduced Ag2VP2O8 materials, which bodes well for enhanced safety of batteries incorporating this material. - Graphical abstract: Structure and galvanostatic intermittent titration-type test data for silver vanadium diphosphate, Ag2VP2O8. Highlights: ► First electrochemical study of a silver vanadium diphosphate, Ag2VP2O8. ► In-situ formation of Ag0 nanoparticles was observed upon electrochemical reduction. ► Structural analysis used to provide insight of the electrochemical behavior

  6. Probing Protein 3D Structures and Conformational Changes Using Electrochemistry-Assisted Isotope Labeling Cross-Linking Mass Spectrometry.

    Science.gov (United States)

    Zheng, Qiuling; Zhang, Hao; Wu, Shiyong; Chen, Hao

    2016-05-01

    This study presents a new chemical cross-linking mass spectrometry (MS) method in combination with electrochemistry and isotope labeling strategy for probing both protein three-dimensional (3D) structures and conformational changes. For the former purpose, the target protein/protein complex is cross-linked with equal mole of premixed light and heavy isotope labeled cross-linkers carrying electrochemically reducible disulfide bonds (i.e., DSP-d0 and DSP-d8 in this study, DSP = dithiobis[succinimidyl propionate]), digested and then electrochemically reduced followed with online MS analysis. Cross-links can be quickly identified because of their reduced intensities upon electrolysis and the presence of doublet isotopic peak characteristics. In addition, electroreduction converts cross-links into linear peptides, facilitating MS/MS analysis to gain increased information about their sequences and modification sites. For the latter purpose of probing protein conformational changes, an altered procedure is adopted, in which the protein in two different conformations is cross-linked using DSP-d0 and DSP-d8 separately, and then the two protein samples are mixed in 1:1 molar ratio. The merged sample is subjected to digestion and electrochemical mass spectrometric analysis. In such a comparative cross-linking experiment, cross-links could still be rapidly recognized based on their responses to electrolysis. More importantly, the ion intensity ratios of light and heavy isotope labeled cross-links reveal the conformational changes of the protein, as exemplified by examining the effect of Ca(2+) on calmodulin conformation alternation. This new cross-linking MS method is fast and would have high value in structural biology. Graphical Abstract ᅟ. PMID:26902947

  7. Probing Protein 3D Structures and Conformational Changes Using Electrochemistry-Assisted Isotope Labeling Cross-Linking Mass Spectrometry

    Science.gov (United States)

    Zheng, Qiuling; Zhang, Hao; Wu, Shiyong; Chen, Hao

    2016-05-01

    This study presents a new chemical cross-linking mass spectrometry (MS) method in combination with electrochemistry and isotope labeling strategy for probing both protein three-dimensional (3D) structures and conformational changes. For the former purpose, the target protein/protein complex is cross-linked with equal mole of premixed light and heavy isotope labeled cross-linkers carrying electrochemically reducible disulfide bonds (i.e., DSP-d0 and DSP-d8 in this study, DSP = dithiobis[succinimidyl propionate]), digested and then electrochemically reduced followed with online MS analysis. Cross-links can be quickly identified because of their reduced intensities upon electrolysis and the presence of doublet isotopic peak characteristics. In addition, electroreduction converts cross-links into linear peptides, facilitating MS/MS analysis to gain increased information about their sequences and modification sites. For the latter purpose of probing protein conformational changes, an altered procedure is adopted, in which the protein in two different conformations is cross-linked using DSP-d0 and DSP-d8 separately, and then the two protein samples are mixed in 1:1 molar ratio. The merged sample is subjected to digestion and electrochemical mass spectrometric analysis. In such a comparative cross-linking experiment, cross-links could still be rapidly recognized based on their responses to electrolysis. More importantly, the ion intensity ratios of light and heavy isotope labeled cross-links reveal the conformational changes of the protein, as exemplified by examining the effect of Ca2+ on calmodulin conformation alternation. This new cross-linking MS method is fast and would have high value in structural biology.

  8. Fully solar-driven thermo- and electrochemistry for advanced oxidation processes (STEP-AOPs) of 2-nitrophenol wastewater.

    Science.gov (United States)

    Nie, Chunhong; Shao, Nan; Wang, Baohui; Yuan, Dandan; Sui, Xin; Wu, Hongjun

    2016-07-01

    The STEP (Solar Thermal Electrochemical Process) for Advanced Oxidation Processes (AOPs, combined to STEP-AOPs), fully driven by solar energy without the input of any other forms of energy and chemicals, is introduced and demonstrated from the theory to experiments. Exemplified by the persistent organic pollutant 2-nitrophenol in water, the fundamental model and practical system are exhibited for the STEP-AOPs to efficiently transform 2-nitrophenol into carbon dioxide, water, and the other substances. The results show that the STEP-AOPs system performs more effectively than classical AOPs in terms of the thermodynamics and kinetics of pollutant oxidation. Due to the combination of solar thermochemical reactions with electrochemistry, the STEP-AOPs system allows the requisite electrolysis voltage of 2-nitrophenol to be experimentally decreased from 1.00 V to 0.84 V, and the response current increases from 18 mA to 40 mA. STEP-AOPs also greatly improve the kinetics of the oxidation at 30 °C and 80 °C. As a result, the removal rate of 2-nitrophenol after 1 h increased from 19.50% at 30 °C to 32.70% at 80 °C at constant 1.90 V. Mechanistic analysis reveals that the oxidation pathway is favorably changed because of thermal effects. The tracking of the reaction displayed that benzenediol and hydroquinone are initial products, with maleic acid and formic acid as sequential carboxylic acid products, and carbon dioxide as the final product. The theory and experiments on STEP-AOPs system exemplified by the oxidation of 2-nitrophenol provide a broad basis for extension of the STEP and AOPs for rapid and efficient treatment of organic wastewater. PMID:27093694

  9. Atomic-scale electrochemistry on the surface of a manganite by scanning tunneling microscopy

    International Nuclear Information System (INIS)

    The doped manganese oxides (manganites) have been widely studied for their colossal magnetoresistive effects, for potential applications in oxide spintronics, electroforming in resistive switching devices, and are materials of choice as cathodes in modern solid oxide fuel cells. However, little experimental knowledge of the dynamics of the surfaces of perovskite manganites at the atomic scale exists. Here, through in-situ scanning tunneling microscopy (STM), we demonstrate atomic resolution on samples of La0.625Ca0.375MnO3 grown on (001) SrTiO3 by pulsed laser deposition. Furthermore, by applying triangular DC waveforms of increasing amplitude to the STM tip, and measuring the tunneling current, we demonstrate the ability to both perform and monitor surface electrochemical processes at the atomic level, including formation of oxygen vacancies and removal and deposition of individual atomic units or clusters. Our work paves the way for better understanding of surface oxygen reactions in these systems

  10. Modeling the electrochemistry of the primary circuits of light water reactors

    International Nuclear Information System (INIS)

    To model the corrosion behaviors of the heat transport circuits of light water reactors, a mixed potential model (NTM) has been developed and applied to both boiling water reactors (BWRs) and pressurized water reactors (PWRs). Using the data generated by the GE/UKEA-Harwell radiolysis model, electrochemical potentials (ECPs) have been calculated for the heat transport circuits of eight BWRs operating under hydrogen water chemistry (HWC). By modeling the corrosion behaviors of these reactors, the effectiveness of HWC at limiting IGSCC and IASCC can be determined. For simulating PWR primary circuits, a chemical-radiolysis model (developed by the authors) was used to generate input parameters for the MPM. Corrosion potentials of Type 304 and 316 SSs in PWR primary environments were calculated using the NTM and were found to be in good agreement with the corrosion potentials measured in the laboratory for simulated PWR primary environments

  11. Reduced Graphene Oxide: Is it a promising catalyst for the electrochemistry of [UO2(CO3)3]4−/[UO2(CO3)3]5−?

    International Nuclear Information System (INIS)

    Highlights: • First report on aqueous electrochemistry of uranium on graphene materials. • Graphene(Nafion)/GC did not show applicability for the anionic analytes. • Electrochemically Reduced Graphene Oxide (ERGNO) was synthesised by cyclic voltammetry. • ERGNO catalysed the electrochemistry of [UVIO2(CO3)3]4-/[UVO2(CO3)3]5-. • Both the cathodic and anodic overpotentials of U(VI)/U(V) reaction decreased on ERGNO. - Abstract: The graphene has been emerging in the electrocatalysis and electroanalysis as the potent surface modifying agents for the working electrodes. However, the aqueous electrochemistry of the actinides on graphene (or graphene type materials) is yet unexplored. In this paper, the aqueous electrochemistry of [UVIO2(CO3)3]4−/[UVO2(CO3)3]5− redox couple was systematically investigated on electrochemically reduced graphene oxide (ERGNO) modified glassy carbon (GC) electrode in saturated Na2CO3 solution (pH ∼12.3). This is the first report on aqueous actinide electrochemistry on graphene materials. The results showed that ERGNO could catalyse the redox chemistry of [UVIO2(CO3)3]4−/[UVO2(CO3)3]5− by reducing both the cathodic and anodic overpotentials compared to bare GC electrode. However, no enhancement in the peak current was observed on ERGNO electrode for the same reaction. Therefore, the present study introduces an appeal for a systematic investigation on the electrochemistry of the actinides at graphene materials to gear up their applications in nuclear technology

  12. Atomic-scale electrochemistry on the surface of a manganite by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Rama K., E-mail: rvv@ornl.gov; Tselev, Alexander; Baddorf, Arthur P. [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); ORNL Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Gianfrancesco, Anthony G. [UT/ORNL Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996 (United States); Kalinin, Sergei V. [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); ORNL Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); UT/ORNL Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2015-04-06

    The doped manganese oxides (manganites) have been widely studied for their colossal magnetoresistive effects, for potential applications in oxide spintronics, electroforming in resistive switching devices, and are materials of choice as cathodes in modern solid oxide fuel cells. However, little experimental knowledge of the dynamics of the surfaces of perovskite manganites at the atomic scale exists. Here, through in-situ scanning tunneling microscopy (STM), we demonstrate atomic resolution on samples of La{sub 0.625}Ca{sub 0.375}MnO{sub 3} grown on (001) SrTiO{sub 3} by pulsed laser deposition. Furthermore, by applying triangular DC waveforms of increasing amplitude to the STM tip, and measuring the tunneling current, we demonstrate the ability to both perform and monitor surface electrochemical processes at the atomic level, including formation of oxygen vacancies and removal and deposition of individual atomic units or clusters. Our work paves the way for better understanding of surface oxygen reactions in these systems.

  13. Transport and electrochemistry based characterization of porous electrodes for CDI applications and comparison with desalination performance

    Science.gov (United States)

    Rios Perez, Carlos; Wilkes, Ellen; Guitierrez, Luis; Hidrovo, Carlos

    2014-11-01

    Development of carbon-based materials with high specific surface area at the end of last century has made researchers to look back at capacitive deionization as a potential desalination technique for brackish water. Several publications evaluate the adsorption capacity of electrode materials under different conditions. Many others present the development/characterization of new electrode materials using electrochemical analysis and other techniques. Although some work has been done to model the electro-adsorption process at the macro and micro-scale, there is still a gap to tie the characterization of the electrodes to their performance. Here a simplified one-dimensional model is used to estimate the characteristic net electro-adsorption velocities for fully-developed or developing regimes in a flow-by capacitive deionization system. This methodology is applied to three commercially available materials with very distinct structure topology to estimate electromigration velocities at a specific solution flow rate. The calculated electro-adsorption rates and other characterization parameters obtained using traditional electrochemical techniques were compared against important desalination performance parameters such as amount of salt adsorbed and desalination proficiency (amount of salt adsorbed per unit of energy). The results obtained show interesting correlations and sometimes-unexpected behavior under constant current and constant voltage operation.

  14. Modeling and experimental validation of CO heterogeneous chemistry and electrochemistry in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Yurkiv, Vitaly

    2010-12-17

    In the present work experimental and numerical modeling studies of the heterogeneously catalyzed and electrochemical oxidation of CO at Nickel/yttria-stabilized zirconia (YSZ) solid oxide fuel cell (SOFC) anode systems were performed to evaluate elementary charge-transfer reaction mechanisms taking place at the three-phase boundary of CO/CO{sub 2} gas-phase, Ni electrode, and YSZ electrolyte. Temperature-programmed desorption and reaction experiments along with density functional theory calculations were performed to determine adsorption/desorption and surface diffusion kinetics as well as thermodynamic data for the CO/CO{sub 2}/Ni and CO/CO{sub 2}/YSZ systems. Based on these data elementary reaction based models with four different charge transfer mechanisms for the electrochemical CO oxidation were developed and applied in numerical simulations of literature experimental electrochemical data such as polarization curves and impedance spectra. Comparison between simulation and experiment demonstrated that only one of the four charge transfer mechanisms can consistently reproduce the electrochemical data over a wide range of operating temperatures and CO/CO{sub 2} gas compositions. (orig.) [German] In der vorliegenden Arbeit wurden experimentelle und numerische Untersuchungen zur heterogen katalysierten und elektrochemischen Oxidation von CO an Anodensystemen (bestehend aus Nickel und yttriumdotiertem Zirkoniumdioxid, YSZ) von Festoxidbrennstoffzellen (engl. Solid Oxide Fuel Cells, SOFCs) ausgefuehrt, um den mikroskopischen Mechanismus der an der CO/CO{sub 2}-Gasphase/Ni-Elektrode/YSZ-Elektrolyt- Dreiphasen-Grenzflaeche ablaufenden Ladungsuebertragungsreaktion aufzuklaeren. Temperaturprogrammierte Desorptionsmessungen (TPD) und Temperaturprogrammierte Reaktionsmessungen (TPR) sowie Dichtefunktionaltheorierechnungen wurden ausgefuehrt, um adsorptions-, desorptions- und reaktionskinetische sowie thermodynamische Daten fuer die CO/CO{sub 2}/Ni- und CO/CO{sub 2}/YSZ

  15. An aptamer-based biosensing platform for highly sensitive detection of platelet-derived growth factor via enzyme-mediated direct electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Deng Kun; Xiang Yang; Zhang Liqun; Chen Qinghai [Laboratory of the Clinical Experimental Base of Biosensor and Microarray, Center of Molecule and Gene Diagnosis, Southwest Hospital, Third Military Medical University, Chongqing 400042 (China); Fu Weiling, E-mail: weilingfu@yahoo.com [Laboratory of the Clinical Experimental Base of Biosensor and Microarray, Center of Molecule and Gene Diagnosis, Southwest Hospital, Third Military Medical University, Chongqing 400042 (China)

    2013-01-08

    Highlights: Black-Right-Pointing-Pointer Direct electrochemistry of glucose oxidase used for signal generation in aptasensor. Black-Right-Pointing-Pointer Using novel nanocomposite for immobilization and signal amplification. Black-Right-Pointing-Pointer Sensitive electrochemical detection of platelet-derived growth factor. - Abstract: In this work, a new label-free electrochemical aptamer-based sensor (aptasensor) was constructed for detection of platelet-derived growth factor (PDGF) based on the direct electrochemistry of glucose oxidase (GOD). For this proposed aptasensor, poly(diallyldimethylammonium chloride) (PDDA)-protected graphene-gold nanoparticles (P-Gra-GNPs) composite was firstly coated on electrode surface to form the interface with biocompatibility and huge surface area for the adsorption of GOD layer. Subsequently, gold nanoclusters (GNCs) were deposited on the surface of GOD to capture PDGF binding aptamer (PBA). Finally, GOD as a blocking reagent was employed to block the remaining active sites of the GNCs and avoid the nonspecific adsorption. With the direct electron transfer of double layer GOD membranes, the aptasensor showed excellent electrochemical response and the peak current decreased linearly with increasing logarithm of PDGF concentration from 0.005 nM to 60 nM with a relatively low limit of detection of 1.7 pM. The proposed aptasensor exhibited high specificity, good reproducibility and long-term stability, which provided a new promising technique for aptamer-based protein detection.

  16. Mathematical modeling of synthesis gas fueled electrochemistry and transport including H2/CO co-oxidation and surface diffusion in solid oxide fuel cell

    Science.gov (United States)

    Bao, Cheng; Jiang, Zeyi; Zhang, Xinxin

    2015-10-01

    Fuel flexibility is a significant advantage of solid oxide fuel cell (SOFC). A comprehensive macroscopic framework is proposed for synthesis gas (syngas) fueled electrochemistry and transport in SOFC anode with two main novelties, i.e. analytical H2/CO electrochemical co-oxidation, and correction of gas species concentration at triple phase boundary considering competitive absorption and surface diffusion. Staring from analytical approximation of the decoupled charge and mass transfer, we present analytical solutions of two defined variables, i.e. hydrogen current fraction and enhancement factor. Giving explicit answer (rather than case-by-case numerical calculation) on how many percent of the current output contributed by H2 or CO and on how great the water gas shift reaction plays role on, this approach establishes at the first time an adaptive superposition mechanism of H2-fuel and CO-fuel electrochemistry for syngas fuel. Based on the diffusion equivalent circuit model, assuming series-connected resistances of surface diffusion and bulk diffusion, the model predicts well at high fuel utilization by keeping fixed porosity/tortuosity ratio. The model has been validated by experimental polarization behaviors in a wide range of operation on a button cell for H2-H2O-CO-CO2-N2 fuel systems. The framework could be helpful to narrow the gap between macro-scale and meso-scale SOFC modeling.

  17. Direct electrochemistry of glucose oxidase and sensing glucose using a screen-printed carbon electrode modified with graphite nanosheets and zinc oxide nanoparticles

    International Nuclear Information System (INIS)

    We have studied the direct electrochemistry of glucose oxidase (GOx) immobilized on electrochemically fabricated graphite nanosheets (GNs) and zinc oxide nanoparticles (ZnO) that were deposited on a screen printed carbon electrode (SPCE). The GNs/ZnO composite was characterized by using scanning electron microscopy and elemental analysis. The GOx immobilized on the modified electrode shows a well-defined redox couple at a formal potential of −0.4 V. The enhanced direct electrochemistry of GOx (compared to electrodes without ZnO or without GNs) indicates a fast electron transfer at this kind of electrode, with a heterogeneous electron transfer rate constant (Ks) of 3.75 s−1. The fast electron transfer is attributed to the high conductivity and large edge plane defects of GNs and good conductivity of ZnO-NPs. The modified electrode displays a linear response to glucose in concentrations from 0.3 to 4.5 mM, and the sensitivity is 30.07 μA mM−1 cm−2. The sensor exhibits a high selectivity, good repeatability and reproducibility, and long term stability. (author)

  18. Probing the nature of electron transfer in metalloproteins on graphene-family materials as nanobiocatalytic scaffold using electrochemistry

    Directory of Open Access Journals (Sweden)

    Sanju Gupta

    2015-03-01

    Full Text Available Graphene-based nanomaterials have shown great promise not only in nanoelectronics due to ultrahigh electron mobility but also as biocatalytic scaffolds owing to irreversible protein surface adsorption and facilitating direct electron transfer. In this work, we synthesized stable dispersions of graphene using liquid-phase exfoliation approach based on non-covalent interactions between graphene and 1-pyrenesulfonic acid sodium salt (Py–1SO3, 1-pyrenemethylamine salt (Py − Me-NH2 and Pluronic® P-123 surfactant using only water as solvent compatible with biomolecules. The resulting graphene nanoplatelets (Gr_LPE are characterized by a combination of analytical (microscopy and spectroscopy techniques revealing mono- to few-layer graphene displaying that the exfoliation efficiency strongly depends upon the type of pyrene-based salts and organic surfactants. Moreover being completely water-based approach, we build robust nanoscaffolds of graphene-family nanomaterials (GFNs namely, monolayer graphene, Gr_LPE (the one prepared with Pluronic® P-123, graphene oxide (GO and its reduced form (rGO on glassy carbon electrode surface with three important metalloproteins include cytochrome c (Cyt c [for electron transfer], myoglobin (Mb [for oxygen storage] and horseradish peroxidase (HRP [for catalyzing the biochemical reaction]. In order to demonstrate the nanobiocatalytical activity of these proteins, we used electrochemical interfacial direct electron transfer (DET kinetics and attempt to determine the rate constant (kET using two different analytical approaches namely, linear sweep voltammetry and Laviron’s theory. We elucidated that all of the metalloproteins retain their structural integrity (secondary structure upon forming mixtures with GFNs confirmed through optical and vibrational spectroscopy and biological activity using electrochemistry. Among the GFNs studied, Gr-LPE, GO and rGO support the efficient electrical wiring of the redox centers

  19. Probing the nature of electron transfer in metalloproteins on graphene-family materials as nanobiocatalytic scaffold using electrochemistry

    International Nuclear Information System (INIS)

    Graphene-based nanomaterials have shown great promise not only in nanoelectronics due to ultrahigh electron mobility but also as biocatalytic scaffolds owing to irreversible protein surface adsorption and facilitating direct electron transfer. In this work, we synthesized stable dispersions of graphene using liquid-phase exfoliation approach based on non-covalent interactions between graphene and 1-pyrenesulfonic acid sodium salt (Py–1SO3), 1-pyrenemethylamine salt (Py − Me-NH2) and Pluronic® P-123 surfactant using only water as solvent compatible with biomolecules. The resulting graphene nanoplatelets (Gr-LPE) are characterized by a combination of analytical (microscopy and spectroscopy) techniques revealing mono- to few-layer graphene displaying that the exfoliation efficiency strongly depends upon the type of pyrene-based salts and organic surfactants. Moreover being completely water-based approach, we build robust nanoscaffolds of graphene-family nanomaterials (GFNs) namely, monolayer graphene, Gr-LPE (the one prepared with Pluronic® P-123), graphene oxide (GO) and its reduced form (rGO) on glassy carbon electrode surface with three important metalloproteins include cytochrome c (Cyt c) [for electron transfer], myoglobin (Mb) [for oxygen storage] and horseradish peroxidase (HRP) [for catalyzing the biochemical reaction]. In order to demonstrate the nanobiocatalytical activity of these proteins, we used electrochemical interfacial direct electron transfer (DET) kinetics and attempt to determine the rate constant (kET) using two different analytical approaches namely, linear sweep voltammetry and Laviron’s theory. We elucidated that all of the metalloproteins retain their structural integrity (secondary structure) upon forming mixtures with GFNs confirmed through optical and vibrational spectroscopy and biological activity using electrochemistry. Among the GFNs studied, Gr-LPE, GO and rGO support the efficient electrical wiring of the redox centers (with

  20. Probing the nature of electron transfer in metalloproteins on graphene-family materials as nanobiocatalytic scaffold using electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sanju, E-mail: sanju.gupta@wku.edu [Department of Physics and Astronomy, Western Kentucky University, 1906 College Heights Blvd. Bowling Green, KY 42101-3576 (United States); Biotechnology Center, Western Kentucky University, 1906 College Heights Blvd. Bowling Green, KY 42101-3576 (United States); Irihamye, Aline [Gatton Academy of Mathematics and Science in Kentucky, Western Kentucky University, 1906 College Heights Blvd. Bowling Green, KY 42101-3576 (United States)

    2015-03-15

    Graphene-based nanomaterials have shown great promise not only in nanoelectronics due to ultrahigh electron mobility but also as biocatalytic scaffolds owing to irreversible protein surface adsorption and facilitating direct electron transfer. In this work, we synthesized stable dispersions of graphene using liquid-phase exfoliation approach based on non-covalent interactions between graphene and 1-pyrenesulfonic acid sodium salt (Py–1SO{sub 3}), 1-pyrenemethylamine salt (Py − Me-NH{sub 2}) and Pluronic{sup ®} P-123 surfactant using only water as solvent compatible with biomolecules. The resulting graphene nanoplatelets (Gr-LPE) are characterized by a combination of analytical (microscopy and spectroscopy) techniques revealing mono- to few-layer graphene displaying that the exfoliation efficiency strongly depends upon the type of pyrene-based salts and organic surfactants. Moreover being completely water-based approach, we build robust nanoscaffolds of graphene-family nanomaterials (GFNs) namely, monolayer graphene, Gr-LPE (the one prepared with Pluronic{sup ®} P-123), graphene oxide (GO) and its reduced form (rGO) on glassy carbon electrode surface with three important metalloproteins include cytochrome c (Cyt c) [for electron transfer], myoglobin (Mb) [for oxygen storage] and horseradish peroxidase (HRP) [for catalyzing the biochemical reaction]. In order to demonstrate the nanobiocatalytical activity of these proteins, we used electrochemical interfacial direct electron transfer (DET) kinetics and attempt to determine the rate constant (k{sub ET}) using two different analytical approaches namely, linear sweep voltammetry and Laviron’s theory. We elucidated that all of the metalloproteins retain their structural integrity (secondary structure) upon forming mixtures with GFNs confirmed through optical and vibrational spectroscopy and biological activity using electrochemistry. Among the GFNs studied, Gr-LPE, GO and rGO support the efficient electrical

  1. Advances in Applied Mechanics

    OpenAIRE

    2014-01-01

    Advances in Applied Mechanics draws together recent significant advances in various topics in applied mechanics. Published since 1948, Advances in Applied Mechanics aims to provide authoritative review articles on topics in the mechanical sciences, primarily of interest to scientists and engineers working in the various branches of mechanics, but also of interest to the many who use the results of investigations in mechanics in various application areas, such as aerospace, chemical, civil, en...

  2. Perspectives on Applied Ethics

    OpenAIRE

    2007-01-01

    Applied ethics is a growing, interdisciplinary field dealing with ethical problems in different areas of society. It includes for instance social and political ethics, computer ethics, medical ethics, bioethics, envi-ronmental ethics, business ethics, and it also relates to different forms of professional ethics. From the perspective of ethics, applied ethics is a specialisation in one area of ethics. From the perspective of social practice applying eth-ics is to focus on ethical aspects and ...

  3. Applied Neuroscience Laboratory Complex

    Data.gov (United States)

    Federal Laboratory Consortium — Located at WPAFB, Ohio, the Applied Neuroscience lab researches and develops technologies to optimize Airmen individual and team performance across all AF domains....

  4. Stochastic Processes in Electrochemistry.

    Science.gov (United States)

    Singh, Pradyumna S; Lemay, Serge G

    2016-05-17

    Stochastic behavior becomes an increasingly dominant characteristic of electrochemical systems as we probe them on the smallest scales. Advances in the tools and techniques of nanoelectrochemistry dictate that stochastic phenomena will become more widely manifest in the future. In this Perspective, we outline the conceptual tools that are required to analyze and understand this behavior. We draw on examples from several specific electrochemical systems where important information is encoded in, and can be derived from, apparently random signals. This Perspective attempts to serve as an accessible introduction to understanding stochastic phenomena in electrochemical systems and outlines why they cannot be understood with conventional macroscopic descriptions. PMID:27120701

  5. Electrochemistry of lunar rocks

    Science.gov (United States)

    Lindstrom, D. J.; Haskin, L. A.

    1979-01-01

    Electrolysis of silicate melts has been shown to be an effective means of producing metals from common silicate materials. No fluxing agents need be added to the melts. From solution in melts of diopside (CaMgSi2O6) composition, the elements Si, Ti, Ni, and Fe have been reduced to their metallic states. Platinum is a satisfactory anode material, but other cathode materials are needed. Electrolysis of compositional analogs of lunar rocks initially produces iron metal at the cathode and oxygen gas at the anode. Utilizing mainly heat and electricity which are readily available from sunlight, direct electrolysis is capable of producing useful metals from common feedstocks without the need for expendable chemicals. This simple process and the products obtained from it deserve further study for use in materials processing in space.

  6. Analysis of Electrochemistry Cells

    International Nuclear Information System (INIS)

    In previous work for SKB, an electrochemical cell was developed to measure pH, corrosion potential of steel and redox potential in artificial groundwater, in the presence of a mass of anaerobically corroding steel wires. Two cells were run for over 7,500 hours. At the end of the test period, the cells were dismantled and the solutions and specimens analysed, to provide a better understanding of the environment within the test cells and the reactions that had taken place on the surfaces of the test electrodes. A thorough visual examination of the electrodes and the cells was carried out and photographs were taken. The wires in the test cells were black, although the film formed in Cell 1 appeared to be thinner than in Cell 2. Some green slime was present in both cells, but not to the same extent. Microscopic examination indicated that the slime was microbial in origin. The solutions were analysed for silicon, iron, calcium, sodium, organic carbon and total inorganic carbon. Given the uncertainties in the analytical techniques, the analyses were within the range expected based on the weights added to make up the test solutions. The composition of the corrosion product on the steel wires was determined by Raman spectroscopy measurements. The corrosion product was shown to be predominantly magnetite (Fe3O4), but there was also an indication of goethite (FeOOH) on samples that were analysed while still wet. This supports the hypothesis of a dual layer oxide film being formed during the anaerobic corrosion of iron. The surfaces of the silver-silver chloride reference electrode and the gold redox electrode were examined by scanning electron microscopy and electron microprobe analysis. There was no evidence for loss of the porous chloride coating from the surface of the reference electrode. The potential of the silver-silver chloride electrode from Cell 1 was measured against a stored silver-silver chloride electrode to check the hypothesis that the silver chloride electrode used in the test cell had converted to a platinum hydrogen electrode. Initially this electrode showed a highly negative potential value, as was observed previously in the test cell, but approximately 14 hours after immersion the electrode assumed the correct potential. The reason for this behaviour is not clear. The effect of changing the pH on the potential of the reference electrode was examined and it was found that it was independent of pH, showing that the potential was not determined by the central platinum wire. The Calomel electrode from Cell 2 was found to have drifted by about 30 mV and the possible reasons for this are discussed in the report. The operation of the pH electrodes from the two cells was checked in solutions of known pH. They were found to be behaving normally and linearly. The calibration of the pH electrodes in various buffer solutions needs to be performed with care as the time to equilibrate to a change in pH can be several days. Due to an experimental difficulty, the test solutions in the electrochemical cells had been contaminated with di-butyl phthalate. The effect of di-butyl phthalate on the pH and composition of artificial groundwater was determined by carrying out a separate experiment in which a sample of groundwater was placed in contact with DBP for 56 days. The organic contaminants in the groundwater were analysed by GC-MS. The organic compounds were either di-butyl phthalate or related compounds. The larger molecules may have been residual contaminants from the manufacture of DBP; the smaller molecules may have been contamination in the original DBP or degradation products from DBP in the test cells. In general, analysis of the cell contents has contributed to a deeper understanding of the processes occurring in anoxic groundwater containing corroding steel and highlighted some of the experimental considerations that should be taken into account in making electrochemical measurements in simulated repository conditions

  7. Electrochemistry of fullerene films

    Energy Technology Data Exchange (ETDEWEB)

    Chlistunoff, J. [Texas Univ., Austin, TX (United States). Dept. of Chemistry and Biochemistry; Cliffel, D. [Texas Univ., Austin, TX (United States). Dept. of Chemistry and Biochemistry; Bard, A.J. [Texas Univ., Austin, TX (United States). Dept. of Chemistry and Biochemistry

    1995-03-01

    The preparation of C{sub 60} films on electrodes by drop coating, Langmuir-Blodgett and electrochemical techniques, and the electrochemical behavior of these films in acetonitrile solutions containing a variety of supporting electrolytes (e.g., quaternary ammonium, alkali metal, and alkaline earth salts) is reviewed. Reduction can form insoluble films with incorporated cations or lead to dissolution. The large splitting between cathodic and anodic waves is discussed in terms of structural rearrange- ments during the redox processes. Studies of C{sub 60} electrodes with the quartz crystal microbalance and with the scanning electrochemical microscope, and by laser-desorption mass spectrometry and surface-enhanced Raman scattering are also discussed. ((orig.))

  8. Electrochemistry of hexanitroazobenzene (HNAB)

    Energy Technology Data Exchange (ETDEWEB)

    Firsich, D.W.

    1985-01-01

    The electrochemical properties of HNAB are explored, including the characterization of its anion, dianion, protonated dianion and diprotonated dianion by cyclic voltammetry, controlled potential coulometry, and visible spectroscopy. The acid/base relationships of these species are defined. The chemistry demonstrated is shown to be useful in exploring the reactivity of HNAB with common metals, and is relevant to the synthesis of HNAB. 2 refs., 5 figs.

  9. Electrochemistry reveals archaeological materials

    OpenAIRE

    Costa, Virginia; Leyssens, Karen; Adriaens, Annemie; Richard, N.; Scholz, Fritz

    2010-01-01

    The characterization of materials constituting cultural artefacts is a challenging step in their conservation, due to the object’s uniqueness and the reduced number of conservation institutes able to supply non-destructive analysis. We propose an alternative analytical tool, which combines accessibility (low cost and portable) and high sensitivity, based on electrochemical linear sweep voltammetry (LSV) with paraffin impregnated graphite electrode (PIGE). To investigate the composition of “wh...

  10. Modern aspects of electrochemistry

    CERN Document Server

    Bockris, J O'M; Conway, B E

    1998-01-01

    This is the latest volume of the series praised by JACS for its ""high standards,"" and by Chemistry and Industry for rendering a ""valuable service."" Experts from academic and industrial laboratories worldwide present: -- Experimental results from the last decade of interfacial studies -- A surprising quantum mechanical treatment of electrode processes -- Recent work in molecular dynamic simulations, which confirms some earlier modelistic approaches and also breaks new ground -- An in-depth look at underpotential deposition on single crystal metals, and -- The practical matter of automated c

  11. DNA-Mediated Electrochemistry

    OpenAIRE

    Gorodetsky, Alon A.; Buzzeo, Marisa C.; Barton, Jacqueline K.

    2008-01-01

    The base pair stack of DNA has been demonstrated as a medium for long-range charge transport chemistry both in solution and at DNA-modified surfaces. This chemistry is exquisitely sensitive to structural perturbations in the base pair stack as occur with lesions, single base mismatches, and protein binding. We have exploited this sensitivity for the development of reliable electrochemical assays based on DNA charge transport at self-assembled DNA monolayers. Here, we discuss the characteristi...

  12. Applied Linguistics: Brazilian Perspectives

    Science.gov (United States)

    Cavalcanti, Marilda C.

    2004-01-01

    The aim of this paper is to present perspectives in Applied Linguistics (AL) against the background of a historical overview of the field in Brazil. I take the stance of looking at AL as a field of knowledge and as a professional area of research. This point of view directs my reflections towards research-based Applied Linguistics carried out from…

  13. Study of the Eu2+ and Eu3+ coexist in LiCl-KCl Eutectic Melt by Spectrophotometry and Electrochemistry Method

    International Nuclear Information System (INIS)

    In order to ensure the pyrochemical process, it is necessary to understand the chemical behavior of lanthanides in the molten salt. Through most of lanthanides in molten salts take trivalent states, Eu, Sm, and Yb are possible to take divalent states under reducing conditions, and Eu(II) is the most stable among them. Those reports suggest the existence of Eu in the chloride systems. In electrochemical analysis with molten salts, yttria stabilized zirconia membrane electrodes (YSZME) are largely used as an activity indicator of oxide anion, O2-. In the present study, the effect of the coexisted Eu2+ on the potentiometric titration of Eu3+ was examined. The spectrophotometry and electrochemistry method could b used to measure the ratio of [Eu2+]/[Eu3+]efficiently. The existence of the europium divalent in the LiCl-KCl-EuCl3 solution has been demonstrated by potentiometric titration method with YSZ electrode and Pt wire as a working electrode

  14. End-of-Discharge and End-of-Life Prediction in Lithium-Ion Batteries with Electrochemistry-Based Aging Models

    Science.gov (United States)

    Daigle, Matthew; Kulkarni, Chetan S.

    2016-01-01

    As batteries become increasingly prevalent in complex systems such as aircraft and electric cars, monitoring and predicting battery state of charge and state of health becomes critical. In order to accurately predict the remaining battery power to support system operations for informed operational decision-making, age-dependent changes in dynamics must be accounted for. Using an electrochemistry-based model, we investigate how key parameters of the battery change as aging occurs, and develop models to describe aging through these key parameters. Using these models, we demonstrate how we can (i) accurately predict end-of-discharge for aged batteries, and (ii) predict the end-of-life of a battery as a function of anticipated usage. The approach is validated through an experimental set of randomized discharge profiles.

  15. Electrochemistry of weakly adsorbed species: Voltammetric analysis of electron transfer between gold electrodes and Ru hexaamine electrostatically interacting with DNA duplexes

    International Nuclear Information System (INIS)

    Highlights: • Electron transfer between the electrode and Ru hexaamine electrostatically bound to DNA was studied. • It is shown that the Laviron theory underestimates the electron transfer rates for this case of weakly adsorbed species. • For such weakly adsorbed species as Ru hexaamine, its surface coverage affects the electron transfer rates. - Abstract: The Laviron formalism, developed for the case of strongly adsorbed species, is widely used for kinetic analysis of surface-confined electron transfer (ET) reactions and determination of ET rate constants ks. However, its applicability and reliability for analysis of ET between electrodes and weakly adsorbed species is unclear. Here, we studied electrochemistry of Ru hexamine (RuHex) electrostatically interacting with double-stranded (ds) DNA tethered to gold electrodes through the alkanethiol linker. Electrostatic interactions between positively charged RuHex and negatively charged sugar-phosphate backbone of DNA are not strong and depend both on the solution ionic strength and the presence of RuHex in the bulk solution. In this work, electrochemistry of RuHex electrostatically bound to dsDNA strands was studied in the presence of 50 μM RuHex by cyclic voltammetry and square wave voltammetry (SWV) and the values of ks were estimated by the Laviron and Komorsky-Lovrić–Lovrić methodologies, respectively. Direct comparative analysis of both procedures evidenced underestimation of the ks values obtained by the Laviron theory as compared to the Komorsky-Lovrić–Lovrić approach. Underestimation ranged between 40 and 50% and depended on the DNA surface coverage, being most pronounced at low surface concentrations of DNA, where the ks was maximal. The results evidence better suitability and reliability of SWV measurements in analysis of kinetics of ET reactions of weakly adsorbed species

  16. Mesothelioma Applied Research Foundation

    Science.gov (United States)

    ... Percentage Donations Tribute Wall Other Giving/Fundraising Opportunities Bitcoin Donation Form FAQs Help us raise awareness and ... Percentage Donations Tribute Wall Other Giving/Fundraising Opportunities Bitcoin Donation Form FAQs © 2013 Mesothelioma Applied Research Foundation, ...

  17. Applied Mathematics Seminar 1982

    International Nuclear Information System (INIS)

    This report contains the abstracts of the lectures delivered at 1982 Applied Mathematics Seminar of the DPD/LCC/CNPq and Colloquy on Applied Mathematics of LCC/CNPq. The Seminar comprised 36 conferences. Among these, 30 were presented by researchers associated to brazilian institutions, 9 of them to the LCC/CNPq, and the other 6 were given by visiting lecturers according to the following distribution: 4 from the USA, 1 from England and 1 from Venezuela. The 1981 Applied Mathematics Seminar was organized by Leon R. Sinay and Nelson do Valle Silva. The Colloquy on Applied Mathematics was held from october 1982 on, being organized by Ricardo S. Kubrusly and Leon R. Sinay. (Author)

  18. Handbook of Applied Analysis

    CERN Document Server

    Papageorgiou, Nikolaos S

    2009-01-01

    Offers an examination of important theoretical methods and procedures in applied analysis. This book details the important theoretical trends in nonlinear analysis and applications to different fields. It is suitable for those working on nonlinear analysis.

  19. Applying contemporary statistical techniques

    CERN Document Server

    Wilcox, Rand R

    2003-01-01

    Applying Contemporary Statistical Techniques explains why traditional statistical methods are often inadequate or outdated when applied to modern problems. Wilcox demonstrates how new and more powerful techniques address these problems far more effectively, making these modern robust methods understandable, practical, and easily accessible.* Assumes no previous training in statistics * Explains how and why modern statistical methods provide more accurate results than conventional methods* Covers the latest developments on multiple comparisons * Includes recent advanc

  20. Applied Literature for Healing,

    Directory of Open Access Journals (Sweden)

    Susanna Marie Anderson

    2014-11-01

    Full Text Available In this qualitative research study interviews conducted with elite participants serve to reveal the underlying elements that unite the richly diverse emerging field of Applied Literature. The basic interpretative qualitative method included a thematic analysis of data from the interviews yielding numerous common elements that were then distilled into key themes that elucidated the beneficial effects of engaging consciously with literature. These themes included developing a stronger sense of self in balance with an increasing connection with community; providing a safe container to engage challenging and potentially overwhelming issues from a stance of empowered action; and fostering a healing space for creativity. The findings provide grounds for uniting the work being done in a range of helping professions into a cohesive field of Applied Literature, which offers effective tools for healing, transformation and empowerment.Keywords: Applied Literature, Bibliotherapy, Poetry Therapy, Arts in Corrections, Arts in Medicine

  1. PSYCHOANALYSIS AS APPLIED AESTHETICS.

    Science.gov (United States)

    Richmond, Stephen H

    2016-07-01

    The question of how to place psychoanalysis in relation to science has been debated since the beginning of psychoanalysis and continues to this day. The author argues that psychoanalysis is best viewed as a form of applied art (also termed applied aesthetics) in parallel to medicine as applied science. This postulate draws on a functional definition of modernity as involving the differentiation of the value spheres of science, art, and religion. The validity criteria for each of the value spheres are discussed. Freud is examined, drawing on Habermas, and seen to have erred by claiming that the psychoanalytic method is a form of science. Implications for clinical and metapsychological issues in psychoanalysis are discussed. PMID:27428582

  2. Applied chemical engineering thermodynamics

    CERN Document Server

    Tassios, Dimitrios P

    1993-01-01

    Applied Chemical Engineering Thermodynamics provides the undergraduate and graduate student of chemical engineering with the basic knowledge, the methodology and the references he needs to apply it in industrial practice. Thus, in addition to the classical topics of the laws of thermodynamics,pure component and mixture thermodynamic properties as well as phase and chemical equilibria the reader will find: - history of thermodynamics - energy conservation - internmolecular forces and molecular thermodynamics - cubic equations of state - statistical mechanics. A great number of calculated problems with solutions and an appendix with numerous tables of numbers of practical importance are extremely helpful for applied calculations. The computer programs on the included disk help the student to become familiar with the typical methods used in industry for volumetric and vapor-liquid equilibria calculations.

  3. Introduction to applied thermodynamics

    CERN Document Server

    Helsdon, R M; Walker, G E

    1965-01-01

    Introduction to Applied Thermodynamics is an introductory text on applied thermodynamics and covers topics ranging from energy and temperature to reversibility and entropy, the first and second laws of thermodynamics, and the properties of ideal gases. Standard air cycles and the thermodynamic properties of pure substances are also discussed, together with gas compressors, combustion, and psychrometry. This volume is comprised of 16 chapters and begins with an overview of the concept of energy as well as the macroscopic and molecular approaches to thermodynamics. The following chapters focus o

  4. Applied statistics with SPSS

    CERN Document Server

    Huizingh, Eelko K R E

    2007-01-01

    Accessibly written and easy to use, Applied Statistics Using SPSS is an all-in-one self-study guide to SPSS and do-it-yourself guide to statistics. Based around the needs of undergraduate students embarking on their own research project, the text's self-help style is designed to boost the skills and confidence of those that will need to use SPSS in the course of doing their research project. The book is pedagogically well developed and contains many screen dumps and exercises, glossary terms and worked examples. Divided into two parts, Applied Statistics Using SPSS covers :

  5. Applied mathematics made simple

    CERN Document Server

    Murphy, Patrick

    1982-01-01

    Applied Mathematics: Made Simple provides an elementary study of the three main branches of classical applied mathematics: statics, hydrostatics, and dynamics. The book begins with discussion of the concepts of mechanics, parallel forces and rigid bodies, kinematics, motion with uniform acceleration in a straight line, and Newton's law of motion. Separate chapters cover vector algebra and coplanar motion, relative motion, projectiles, friction, and rigid bodies in equilibrium under the action of coplanar forces. The final chapters deal with machines and hydrostatics. The standard and conte

  6. Retransmission Steganography Applied

    CERN Document Server

    Mazurczyk, Wojciech; Szczypiorski, Krzysztof

    2010-01-01

    This paper presents experimental results of the implementation of network steganography method called RSTEG (Retransmission Steganography). The main idea of RSTEG is to not acknowledge a successfully received packet to intentionally invoke retransmission. The retransmitted packet carries a steganogram instead of user data in the payload field. RSTEG can be applied to many network protocols that utilize retransmissions. We present experimental results for RSTEG applied to TCP (Transmission Control Protocol) as TCP is the most popular network protocol which ensures reliable data transfer. The main aim of the performed experiments was to estimate RSTEG steganographic bandwidth and detectability by observing its influence on the network retransmission level.

  7. Estudio comparativo de la resolución de problemas en el rendimiento estudiantil en el contenido de electroquímica (COMPARATIVE STUDY OF THE RESOLUTION OF PROBLEMS IN THE STUDENT YIELD ON THE CONTENT OF ELECTROCHEMISTRY

    Directory of Open Access Journals (Sweden)

    Di’ Bacco Vera Lucia

    2009-04-01

    Full Text Available Resumen:Este estudio comparó las metodologías de resolución de problemas de: Reif, Durán y García, a través del rendimiento estudiantil en el contenido de electroquímica. La muestra estuvo representada por 73 estudiantes del Primer Año de Ciencias de la Unidad Educativa Nacional "El Eneal" del Municipio Crespo, Estado Lara-Venezuela, año escolar 2006-2007. Veinticinco (25 aprendices pertenecen al grupo experimental uno (GE1 y los grupos experimentales dos (GE2 y tres (GE3 están conformados por veinticuatro (24 estudiantes cada uno. Antes de la aplicación de las metodologías, se administró una prueba de conocimientos previos a los tres grupos experimentales; determinándose que los grupos son homogéneos. Al finalizar las tres metodologías, se les aplicó a los tres grupos una post-prueba. Los resultados permitieron concluir que no existe diferencia, estadísticamente significativa, entre el rendimiento estudiantil, en términos del promedio de calificaciones, por los tres grupos que recibieron los tratamientos con las tres estrategias de resolución de problemas utilizadas.Abstract:This study compared the methodologies of resolution of problems: Reif, and García Durán, through student performance on the content of electrochemistry. The sample was represented by 73 students from the First Year of Science Education National Unity "The Eneal" Crespo Municipio Crespo, Estado Lara-Venezuela, 2006-2007 school year. Twenty-five (25 trainees belong to an experimental group (GE1 and two experimental groups (GE2 and three (GE3 are composed of twenty-four (24 students each. Before the application of methodologies, were administered a test of knowledge prior to the three experimental groups, determined that the groups are homogeneous. At the end of the three methodologies were applied to all three groups a post-test.The results allowed concluding that statistically significant difference between the student yields in terms of the average of

  8. Applying Mathematical Processes (AMP)

    Science.gov (United States)

    Kathotia, Vinay

    2011-01-01

    This article provides insights into the "Applying Mathematical Processes" resources, developed by the Nuffield Foundation. It features Nuffield AMP activities--and related ones from Bowland Maths--that were designed to support the teaching and assessment of key processes in mathematics--representing a situation mathematically, analysing,…

  9. Applied Behavior Analysis

    Science.gov (United States)

    Szapacs, Cindy

    2006-01-01

    Teaching strategies that work for typically developing children often do not work for those diagnosed with an autism spectrum disorder. However, teaching strategies that work for children with autism do work for typically developing children. In this article, the author explains how the principles and concepts of Applied Behavior Analysis can be…

  10. Essays on Applied Microeconomics

    Science.gov (United States)

    Mejia Mantilla, Carolina

    2013-01-01

    Each chapter of this dissertation studies a different question within the field of Applied Microeconomics. The first chapter examines the mid- and long-term effects of the 1998 Asian Crisis on the educational attainment of Indonesian children ages 6 to 18, at the time of the crisis. The effects are identified as deviations from a linear trend for…

  11. Applied singular integral equations

    CERN Document Server

    Mandal, B N

    2011-01-01

    The book is devoted to varieties of linear singular integral equations, with special emphasis on their methods of solution. It introduces the singular integral equations and their applications to researchers as well as graduate students of this fascinating and growing branch of applied mathematics.

  12. Applied Statistics with SPSS

    Science.gov (United States)

    Huizingh, Eelko K. R. E.

    2007-01-01

    Accessibly written and easy to use, "Applied Statistics Using SPSS" is an all-in-one self-study guide to SPSS and do-it-yourself guide to statistics. What is unique about Eelko Huizingh's approach is that this book is based around the needs of undergraduate students embarking on their own research project, and its self-help style is designed to…

  13. Applied Control Systems Design

    CERN Document Server

    Mahmoud, Magdi S

    2012-01-01

    Applied Control System Design examines several methods for building up systems models based on real experimental data from typical industrial processes and incorporating system identification techniques. The text takes a comparative approach to the models derived in this way judging their suitability for use in different systems and under different operational circumstances. A broad spectrum of control methods including various forms of filtering, feedback and feedforward control is applied to the models and the guidelines derived from the closed-loop responses are then composed into a concrete self-tested recipe to serve as a check-list for industrial engineers or control designers. System identification and control design are given equal weight in model derivation and testing to reflect their equality of importance in the proper design and optimization of high-performance control systems. Readers’ assimilation of the material discussed is assisted by the provision of problems and examples. Most of these e...

  14. Essays in Applied Econometrics

    OpenAIRE

    Michèle A. Weynandt

    2014-01-01

    This thesis includes three essays in applied econometrics. The first and third chapters focus on labor market outcomes of minority group members, while the second focuses on education. Chapter 1 deals with the relationship between sexual orientation, gender, partnership, and labor outcomes. I suggest that if there are compensating differentials and a gender gap in potential wages, an income effect can lead partnered gay men to jobs with lower wages and higher amenities than partnered straight...

  15. Applied Economics in Teaching

    Institute of Scientific and Technical Information of China (English)

    朱红萍

    2009-01-01

    This paper explains some plain phenomena in teaching and class management with an economic view. Some basic economic principles mentioned therein are: everything has its opportunity cost; the marginal utility of consumption of any kind is diminishing; Game theory is everywhere. By applying the economic theories to teaching, it is of great help for teachers to understand the students' behavior and thus improve the teaching effectiveness and efficiency.

  16. Methods of applied mathematics

    CERN Document Server

    Hildebrand, Francis B

    1992-01-01

    This invaluable book offers engineers and physicists working knowledge of a number of mathematical facts and techniques not commonly treated in courses in advanced calculus, but nevertheless extremely useful when applied to typical problems in many different fields. It deals principally with linear algebraic equations, quadratic and Hermitian forms, operations with vectors and matrices, the calculus of variations, and the formulations and theory of linear integral equations. Annotated problems and exercises accompany each chapter.

  17. Applied Logic in Engineering

    OpenAIRE

    Spichkova, Maria

    2016-01-01

    Logic not only helps to solve complicated and safety-critical problems, but also disciplines the mind and helps to develop abstract thinking, which is very important for any area of Engineering. In this technical report, we present an overview of common challenges in teaching of formal methods and discuss our experiences from the course Applied Logic in Engineering. This course was taught at TU Munich, Germany, in Winter Semester 2012/2013.

  18. Applied longitudinal analysis

    CERN Document Server

    Fitzmaurice, Garrett M; Ware, James H

    2012-01-01

    Praise for the First Edition "". . . [this book] should be on the shelf of everyone interested in . . . longitudinal data analysis.""-Journal of the American Statistical Association   Features newly developed topics and applications of the analysis of longitudinal data Applied Longitudinal Analysis, Second Edition presents modern methods for analyzing data from longitudinal studies and now features the latest state-of-the-art techniques. The book emphasizes practical, rather than theoretical, aspects of methods for the analysis of diverse types of lo

  19. Essays on Applied Microeconomics

    OpenAIRE

    Lee, Hoan Soo

    2013-01-01

    Empirical and theoretical topics in applied microeconomics are discussed in this dissertation. The first essay identifies and measures managerial advantages from access to high-quality deals in venture capital investments. The underlying social network of Harvard Business School MBA venture capitalists and entrepreneurs is used to proxy availability of deal access. Random section assignment of HBS MBA graduates provides a key exogenous variation for identification. Being socially connected to...

  20. Applied statistics for economists

    CERN Document Server

    Lewis, Margaret

    2012-01-01

    This book is an undergraduate text that introduces students to commonly-used statistical methods in economics. Using examples based on contemporary economic issues and readily-available data, it not only explains the mechanics of the various methods, it also guides students to connect statistical results to detailed economic interpretations. Because the goal is for students to be able to apply the statistical methods presented, online sources for economic data and directions for performing each task in Excel are also included.

  1. Coupled optical absorption, charge carrier separation, and surface electrochemistry in surface disordered/hydrogenated TiO2 for enhanced PEC water splitting reaction.

    Science.gov (United States)

    Behara, Dilip Kumar; Ummireddi, Ashok Kumar; Aragonda, Vidyasagar; Gupta, Prashant Kumar; Pala, Raj Ganesh S; Sivakumar, Sri

    2016-03-28

    The central governing factors that influence the efficiency of photoelectrochemical (PEC) water splitting reaction are photon absorption, effective charge-carrier separation, and surface electrochemistry. Attempts to improve one of the three factors may debilitate other factors and we explore such issues in hydrogenated TiO2, wherein a significant increase in optical absorption has not resulted in a significant increase in PEC performance, which we attribute to the enhanced recombination rate due to the formation of amorphization/disorderness in the bulk during the hydrogenation process. To this end, we report a methodology to increase the charge-carrier separation with enhanced optical absorption of hydrogenated TiO2. Current methodology involves hydrogenation of non-metal (N and S) doped TiO2 which comprises (1) lowering of the band gap through shifting of the valence band via less electronegative non-metal N, S-doping, (2) lowering of the conduction band level and the band gap via formation of the Ti(3+) state and oxygen vacancies by hydrogenation, and (3) material processing to obtain a disordered surface structure which favors higher electrocatalytic (EC) activity. This design strategy yields enhanced PEC activity (%ABPE = 0.38) for the N-S co-doped TiO2 sample hydrogenated at 800 °C for 24 h over possible combinations of N-S co-doped TiO2 samples hydrogenated at 500 °C/24 h, 650 °C/24 h and 800 °C/72 h. This suggests that hydrogenation at lower temperatures does not result in much increase in optical absorption and prolonged hydrogenation results in an increase in optical absorption but a decrease in charge carrier separation by forming disorderness/oxygen vacancies in the bulk. Furthermore, the difference in double layer capacitance (C(dl)) calculated from electrochemical impedance spectroscopy (EIS) measurements of these samples reflects the change in the electrochemical surface area (ECSA) and facilitates assessing the key role of surface

  2. Applied ALARA techniques

    International Nuclear Information System (INIS)

    The presentation focuses on some of the time-proven and new technologies being used to accomplish radiological work. These techniques can be applied at nuclear facilities to reduce radiation doses and protect the environment. The last reactor plants and processing facilities were shutdown and Hanford was given a new mission to put the facilities in a safe condition, decontaminate, and prepare them for decommissioning. The skills that were necessary to operate these facilities were different than the skills needed today to clean up Hanford. Workers were not familiar with many of the tools, equipment, and materials needed to accomplish:the new mission, which includes clean up of contaminated areas in and around all the facilities, recovery of reactor fuel from spent fuel pools, and the removal of millions of gallons of highly radioactive waste from 177 underground tanks. In addition, this work has to be done with a reduced number of workers and a smaller budget. At Hanford, facilities contain a myriad of radioactive isotopes that are 2048 located inside plant systems, underground tanks, and the soil. As cleanup work at Hanford began, it became obvious early that in order to get workers to apply ALARA and use hew tools and equipment to accomplish the radiological work it was necessary to plan the work in advance and get radiological control and/or ALARA committee personnel involved early in the planning process. Emphasis was placed on applying,ALARA techniques to reduce dose, limit contamination spread and minimize the amount of radioactive waste generated. Progress on the cleanup has,b6en steady and Hanford workers have learned to use different types of engineered controls and ALARA techniques to perform radiological work. The purpose of this presentation is to share the lessons learned on how Hanford is accomplishing radiological work

  3. Applied linear regression

    CERN Document Server

    Weisberg, Sanford

    2005-01-01

    Master linear regression techniques with a new edition of a classic text Reviews of the Second Edition: ""I found it enjoyable reading and so full of interesting material that even the well-informed reader will probably find something new . . . a necessity for all of those who do linear regression."" -Technometrics, February 1987 ""Overall, I feel that the book is a valuable addition to the now considerable list of texts on applied linear regression. It should be a strong contender as the leading text for a first serious course in regression analysis."" -American Scientist, May-June 1987

  4. Applied impulsive mathematical models

    CERN Document Server

    Stamova, Ivanka

    2016-01-01

    Using the theory of impulsive differential equations, this book focuses on mathematical models which reflect current research in biology, population dynamics, neural networks and economics. The authors provide the basic background from the fundamental theory and give a systematic exposition of recent results related to the qualitative analysis of impulsive mathematical models. Consisting of six chapters, the book presents many applicable techniques, making them available in a single source easily accessible to researchers interested in mathematical models and their applications. Serving as a valuable reference, this text is addressed to a wide audience of professionals, including mathematicians, applied researchers and practitioners.

  5. Applied logistic regression

    CERN Document Server

    Hosmer, David W; Sturdivant, Rodney X

    2013-01-01

     A new edition of the definitive guide to logistic regression modeling for health science and other applications This thoroughly expanded Third Edition provides an easily accessible introduction to the logistic regression (LR) model and highlights the power of this model by examining the relationship between a dichotomous outcome and a set of covariables. Applied Logistic Regression, Third Edition emphasizes applications in the health sciences and handpicks topics that best suit the use of modern statistical software. The book provides readers with state-of-

  6. SIFT applied to CBIR

    Directory of Open Access Journals (Sweden)

    ALMEIDA, J.

    2009-12-01

    Full Text Available Content-Based Image Retrieval (CBIR is a challenging task. Common approaches use only low-level features. Notwithstanding, such CBIR solutions fail on capturing some local features representing the details and nuances of scenes. Many techniques in image processing and computer vision can capture these scene semantics. Among them, the Scale Invariant Features Transform~(SIFT has been widely used in a lot of applications. This approach relies on the choice of several parameters which directly impact its effectiveness when applied to retrieve images. In this paper, we discuss the results obtained in several experiments proposed to evaluate the application of the SIFT in CBIR tasks.

  7. Applied linear regression

    CERN Document Server

    Weisberg, Sanford

    2013-01-01

    Praise for the Third Edition ""...this is an excellent book which could easily be used as a course text...""-International Statistical Institute The Fourth Edition of Applied Linear Regression provides a thorough update of the basic theory and methodology of linear regression modeling. Demonstrating the practical applications of linear regression analysis techniques, the Fourth Edition uses interesting, real-world exercises and examples. Stressing central concepts such as model building, understanding parameters, assessing fit and reliability, and drawing conclusions, the new edition illus

  8. Applied energy an introduction

    CERN Document Server

    Abdullah, Mohammad Omar

    2012-01-01

    Introduction to Applied EnergyGeneral IntroductionEnergy and Power BasicsEnergy EquationEnergy Generation SystemsEnergy Storage and MethodsEnergy Efficiencies and LossesEnergy industry and Energy Applications in Small -Medium Enterprises (SME) industriesEnergy IndustryEnergy-Intensive industryEnergy Applications in SME Energy industriesEnergy Sources and SupplyEnergy SourcesEnergy Supply and Energy DemandEnergy Flow Visualization and Sankey DiagramEnergy Management and AnalysisEnergy AuditsEnergy Use and Fuel Consumption StudyEnergy Life-Cycle AnalysisEnergy and EnvironmentEnergy Pollutants, S

  9. Applied nonparametric statistical methods

    CERN Document Server

    Sprent, Peter

    2007-01-01

    While preserving the clear, accessible style of previous editions, Applied Nonparametric Statistical Methods, Fourth Edition reflects the latest developments in computer-intensive methods that deal with intractable analytical problems and unwieldy data sets. Reorganized and with additional material, this edition begins with a brief summary of some relevant general statistical concepts and an introduction to basic ideas of nonparametric or distribution-free methods. Designed experiments, including those with factorial treatment structures, are now the focus of an entire chapter. The text also e

  10. Applied Semantic Web Technologies

    CERN Document Server

    Sugumaran, Vijayan

    2011-01-01

    The rapid advancement of semantic web technologies, along with the fact that they are at various levels of maturity, has left many practitioners confused about the current state of these technologies. Focusing on the most mature technologies, Applied Semantic Web Technologies integrates theory with case studies to illustrate the history, current state, and future direction of the semantic web. It maintains an emphasis on real-world applications and examines the technical and practical issues related to the use of semantic technologies in intelligent information management. The book starts with

  11. Applied complex variables

    CERN Document Server

    Dettman, John W

    1965-01-01

    Analytic function theory is a traditional subject going back to Cauchy and Riemann in the 19th century. Once the exclusive province of advanced mathematics students, its applications have proven vital to today's physicists and engineers. In this highly regarded work, Professor John W. Dettman offers a clear, well-organized overview of the subject and various applications - making the often-perplexing study of analytic functions of complex variables more accessible to a wider audience. The first half of Applied Complex Variables, designed for sequential study, is a step-by-step treatment of fun

  12. Investigations of thiosulfate accumulation on 304 stainless steel in neutral solutions by radioactive labeling, electrochemistry, Auger electron and X-ray photoelectron spectroscopy methods

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, A.E.; Kolics, A.; Wieckowski, A. [Univ. of Illinois, Urbana, IL (United States)

    1997-02-01

    Thiosulfate accumulation on 304 stainless steel in near neutral solutions (pH {approximately}5.6) was studied using in situ techniques: electrochemistry and radiochemistry, as well as by Auger electron spectroscopy depth profiling and angle-resolved x-ray photoelectron spectroscopy in ultrahigh vacuum. It was found that thiosulfate accumulation is an irreversible process and occurs over a broad electrode potential range. Thiosulfate surface concentration is very small, below {minus}1.0 V vs. Ag/AgCl reference. In the potential range from {minus}1.0 to 0.50 V the surface concentration increases linearly with potential, reaches a maximum at {minus}0.30 V, and at even more positive potentials, decreases to a slightly lower level. Ultrahigh vacuum spectroscopic measurements indicate that the irreversible surface behavior can be attributed to thiosulfate incorporation into the substrate passive film. The present data obtained with 304 stainless steel are compared to previous results published from this laboratory on thiosulfate adsorption on 316 stainless steel, and the role of molybdenum surface enrichment in the thiosulfate accumulation reversibility is discussed. The effect of chloride on thiosulfate accumulation was also investigated. At high concentration of chloride, thiosulfate is desorbed from the surface due to chloride-induced dissolution of the stainless steel. At very negative potentials, the thiosulfate surface concentration increases upon chloride addition, most probably due to the surface microroughening caused by chloride adsorption.

  13. Nanocrystalline TiO2 films containing sulfur and gold: Synthesis, characterization and application to immobilize and direct electrochemistry of cytochrome c

    Science.gov (United States)

    Rafiee-Pour, Hossain-Ali; Hamadanian, Masood; Koushali, Samaneh Katebi

    2016-02-01

    In this paper, nanoporous titanium dioxide (TiO2) film was used for cytochrome c (cyt c) immobilization as an electrode substrate for electrochemical redox activity of the adsorbed cyt c. The result of cyclic voltammetry exhibited a pair of well-defined and quasi-reversible peaks for direct electron transfer of cyt c (formal potential [E0‧ = (Epa + Epc)/2] of 53 mV versus Ag/AgCl). In addition the effect of metal and nonmetal ions (Au, S) co-doping on the efficiency of TiO2 nanoparticles (prepared by combining sol-gel and photo-deposition methods) on the cyt c immobilization process was investigated. The results exhibited that the Au, S-co-doped TiO2 (Au/S-TiO2) with a spheroidal shape demonstrates a smaller grain size than the pure TiO2. Meanwhile, the UV-vis DRS of Au/S-TiO2 showed a considerable red shift to the visible region. As a result, it was found that 4% Au/0.1% S-TiO2 had the highest efficiency for cytochrome c immobilization. The results showed that the peak currents were higher after the annealing of the TiO2 film. This observation suggests that the use of TiO2 films may be advantageous for the development of nanoporous biosensors employing reductive electrochemistry.

  14. Direct Electrochemistry of Glucose Oxidase Immobilized on Chitosan-gold Nanoparticle Composite Film on Glassy Carbon Electrodes and Its Biosensing Application

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The direct electrochemistry of glucose oxidase (Gox) immobilized on a composite matrix based on chitosan (CHIT) and Au nanoparticles (Au NP) underlying on a glassy carbon electrode was achieved. The cyclic voltam-metry and electrochemical impedance spectroscopy were used to characterize the modified electrode. In deaerated buffer solutions, the cyclic voltammetry of the composite films of Gox-Au NP-CHIT showed a pair of well-behaved redox peaks that were assigned to the redox reaction of Gox, confirming the effective immobilization of Gox on the composite film. The electron transfer rate constant was estimated to be 15.6 s-1, indicating a high electron transfer between the Gox redox center and electrode. The combination of CHIT and Au NP also promoted the stability of Gox in the composite film and retained its bioactivity, which might have the potential application to glucose determination. The calculated apparent Michaelis-Menten constant was 10.1 mmol·L-1. Furthermore, the proposed biosensor could be used for the determination of glucose in human plasma samples.

  15. A Novel Hydrogen Peroxide Sensor via the Direct Electrochemistry of Horseradish Peroxidase Immobilized on Colloidal Gold Modified Screen-printed Electrode

    Directory of Open Access Journals (Sweden)

    Huangxian Ju

    2003-09-01

    Full Text Available The direct electrochemistry of horseradish peroxidase (HRP immobilized on a colloidal gold modified screen-printed carbon electrode (HRP-Au-SPCE and its application as a disposable sensor were studied. The immobilized HRP displayed a couple of stable and well-defined redox peaks with a formal potential of –0.338 V (vs. SCE and a heterogeneous electron transfer rate constant of (0.75±0.04 s-1 in 0.1 M pH 7.0 PBS. It showed a highly thermal stability, fast amperometric response and an electrocatalytic activity to the reduction of hydrogen peroxide (H2O2 without the aid of an electron mediator. The biosensor exhibited high sensitivity, good reproducibility, and long-term stability for the determination of H2O2 with a linear range from 0.8 μM to 1.0 mM and a detection limit of 0. 4 μM at 3σ. The variation coefficients are 2.7 % and 2.3 % for over 10 successive assays at the H2O2 concentrations of 8.0 and 20 μM, respectively. The K M app for H2O2 sensor was determined to be 1.3 mM.

  16. Synthesis, structure, and electrochemistry and magnetic properties of a novel 1D homochiral MnIII(5-Brsalen) coordination polymer with left-handed helical character

    Science.gov (United States)

    Dong, Dapeng; Yu, Naisen; Zhao, Haiyan; Liu, Dedi; Liu, Jia; Li, Zhenghua; Liu, Dongping

    2016-01-01

    A novel homochiral manganese (III) Mn(5-Brsalen) coordination polymer with left-handed helical character by spontaneous resolution on crystallization by using Mn(5-Brsalen) and 4,4-bipyridine, [MnIII(5-Brsalen)(4,4-bipy)]·ClO4·CH3OH (1) (4,4-bipy = 4,4-bipyridine) has been synthesized and structurally characterized by X-ray single-crystal diffraction, elemental analysis and infrared spectroscopy. In compound 1, each manganese(III) anion is six-coordinate octahedral being bonded to four atoms of 5-Brsalen ligand in an equatorial plane and two nitrogen atoms from a 4,4-bipyridine ligand in axial positions. The structure of compound 1 can be described a supramolecular 2D-like structure which was formed by the intermolecular π-stacking interactions between the neighboring chains of the aromatic rings of 4,4-bipyridine and 5-Brsalen molecules. UV-vis absorption spectrum, electrochemistry and magnetic properties of the compound 1 have also been studied.

  17. Pseudo-single-crystal electrochemistry on polycrystalline electrodes: visualizing activity at grains and grain boundaries on platinum for the Fe2+/Fe3+ redox reaction.

    Science.gov (United States)

    Aaronson, Barak D B; Chen, Chang-Hui; Li, Hongjiao; Koper, Marc T M; Lai, Stanley C S; Unwin, Patrick R

    2013-03-13

    The influence of electrode surface structure on electrochemical reaction rates and mechanisms is a major theme in electrochemical research, especially as electrodes with inherent structural heterogeneities are used ubiquitously. Yet, probing local electrochemistry and surface structure at complex surfaces is challenging. In this paper, high spatial resolution scanning electrochemical cell microscopy (SECCM) complemented with electron backscatter diffraction (EBSD) is demonstrated as a means of performing 'pseudo-single-crystal' electrochemical measurements at individual grains of a polycrystalline platinum electrode, while also allowing grain boundaries to be probed. Using the Fe(2+/3+) couple as an illustrative case, a strong correlation is found between local surface structure and electrochemical activity. Variations in electrochemical activity for individual high index grains, visualized in a weakly adsorbing perchlorate medium, show that there is higher activity on grains with a significant (101) orientation contribution, compared to those with (001) and (111) contribution, consistent with findings on single-crystal electrodes. Interestingly, for Fe(2+) oxidation in a sulfate medium a different pattern of activity emerges. Here, SECCM reveals only minor variations in activity between individual grains, again consistent with single-crystal studies, with a greatly enhanced activity at grain boundaries. This suggests that these sites may contribute significantly to the overall electrochemical behavior measured on the macroscale. PMID:23405963

  18. The Microscale Synthesis and Electrochemistry of Low-Valent Mononuclear Complexes (h3-C3H5)Fe(CO)3 X (X = I, Br, Cl)

    Science.gov (United States)

    Mocellin, Enrico; Russell, Richard; Ravera, Mauro

    1998-06-01

    The experimental content of this paper will appeal to pedagogues and students who might be looking for new ideas that have an element of challenge. By combining experimental procedures which place microscale, chemical synthesis, and an inclusive, unified, product characterization in perspective, we have afforded the student the scope to obtain progressive, disciplined results and the opportunity to discuss these in the subsequent reporting. By this process, it is our experience that the students often identify with the practical work that is being undertaken, and they develop considerable empathy during their contribution to the "discovery" process that this laboratory program offers. The experimental work can be abbreviated to a single compound, subdivided into synthesis or electrochemistry, or extended to macroscale and other instrumental techniques of characterization, thus offering opportunities to accommodate time constraints, class results combination and discussion, and individual student enthusiasm. We believe that having to accept and/or constructively criticize sequential experimental results, collected by fellow students, mimics more realistically the practice of chemistry at the workplace and can build enthusiasm and elicit contagious fellowship from the class. All of these aspects can simply be achieved by utilizing the listed journals and references therein. Most importantly, it affords the students the opportunity to extricate themselves as innocent bystanders from the conventional "single experiment" practical laboratory to a path of practice and achievement in the scientific method.

  19. Applied plasma physics

    International Nuclear Information System (INIS)

    Applied Plasma Physics is a major sub-organizational unit of the MFE Program. It includes Fusion Plasma Theory and Experimental Plasma Research. The Fusion Plasma Theory group has the responsibility for developing theoretical-computational models in the general areas of plasma properties, equilibrium, stability, transport, and atomic physics. This group has responsibility for giving guidance to the mirror experimental program. There is a formal division of the group into theory and computational; however, in this report the efforts of the two areas are not separated since many projects have contributions from members of both. Under the Experimental Plasma Research Program, we are developing the intense, pulsed neutral-beam source (IPINS) for the generation of a reversed-field configuration on 2XIIB. We are also studying the feasibility of utilizing certain neutron-detection techniques as plasma diagnostics in the next generation of thermonuclear experiments

  20. Contributions to Applied Cartography

    Directory of Open Access Journals (Sweden)

    Radovan Pavić

    2012-12-01

    Full Text Available According to the increasing awareness of the importance, advantagesand feasibility of representing/visualizing spatial relations and spatial content through corresponding cartography –maps are becoming increasingly more frequent and elaborate when one needs to represent some aspect of reality from various standpoints: economical, natural scientific or politological. Some contents practically impose the need for applied cartography which is especially true of international-political, military, geopolitical and transport issues. Therefore, mass communication media have been increasingly accepting and adopting specific cartography as significant content which successfully compete with the importance of the text itself – this is the case everywhere, including in Croatia. The French geographical-political-cartographic school is the model and exceptional accomplishment. It also has predecessors in the German/Nazi geopolitical school from the first half of the 20th century.

  1. Applied number theory

    CERN Document Server

    Niederreiter, Harald

    2015-01-01

    This textbook effectively builds a bridge from basic number theory to recent advances in applied number theory. It presents the first unified account of the four major areas of application where number theory plays a fundamental role, namely cryptography, coding theory, quasi-Monte Carlo methods, and pseudorandom number generation, allowing the authors to delineate the manifold links and interrelations between these areas.  Number theory, which Carl-Friedrich Gauss famously dubbed the queen of mathematics, has always been considered a very beautiful field of mathematics, producing lovely results and elegant proofs. While only very few real-life applications were known in the past, today number theory can be found in everyday life: in supermarket bar code scanners, in our cars’ GPS systems, in online banking, etc.  Starting with a brief introductory course on number theory in Chapter 1, which makes the book more accessible for undergraduates, the authors describe the four main application areas in Chapters...

  2. Applied mechanics of solids

    CERN Document Server

    Bower, Allan F

    2009-01-01

    Modern computer simulations make stress analysis easy. As they continue to replace classical mathematical methods of analysis, these software programs require users to have a solid understanding of the fundamental principles on which they are based. Develop Intuitive Ability to Identify and Avoid Physically Meaningless Predictions Applied Mechanics of Solids is a powerful tool for understanding how to take advantage of these revolutionary computer advances in the field of solid mechanics. Beginning with a description of the physical and mathematical laws that govern deformation in solids, the text presents modern constitutive equations, as well as analytical and computational methods of stress analysis and fracture mechanics. It also addresses the nonlinear theory of deformable rods, membranes, plates, and shells, and solutions to important boundary and initial value problems in solid mechanics. The author uses the step-by-step manner of a blackboard lecture to explain problem solving methods, often providing...

  3. Applied plasma physics

    International Nuclear Information System (INIS)

    Applied Plasma Physics is a major sub-organizational unit of the MFE Porgram. It includes Fusion Plasma Theory and Experimental Plasma Research. Fusion Plasma Theory has the responsibility for developing theoretical-computational models in the general areas of plasma properties, equilibrium, stability, transport, and atomic physics. This group has responsibility for giving guidance to the mirror experimental program. There is a formal division of the group into theory and computational; however, in this report the efforts of the two areas are not separated since many projects have contributions from members of both. Under Experimental Plasma Research, we are developing the intense, pulsed ion-neutral source (IPINS) for the generation of a reversed-field configuration on 2XIIB. We are also studying the feasibility of utilizing certain neutron-detection techniques as plasma diagnostics in the next generation of thermonuclear experiments

  4. Applied multivariate statistical analysis

    CERN Document Server

    Härdle, Wolfgang Karl

    2015-01-01

    Focusing on high-dimensional applications, this 4th edition presents the tools and concepts used in multivariate data analysis in a style that is also accessible for non-mathematicians and practitioners.  It surveys the basic principles and emphasizes both exploratory and inferential statistics; a new chapter on Variable Selection (Lasso, SCAD and Elastic Net) has also been added.  All chapters include practical exercises that highlight applications in different multivariate data analysis fields: in quantitative financial studies, where the joint dynamics of assets are observed; in medicine, where recorded observations of subjects in different locations form the basis for reliable diagnoses and medication; and in quantitative marketing, where consumers’ preferences are collected in order to construct models of consumer behavior.  All of these examples involve high to ultra-high dimensions and represent a number of major fields in big data analysis. The fourth edition of this book on Applied Multivariate ...

  5. Applied partial differential equations

    CERN Document Server

    Logan, J David

    2015-01-01

    This text presents the standard material usually covered in a one-semester, undergraduate course on boundary value problems and PDEs.  Emphasis is placed on motivation, concepts, methods, and interpretation, rather than on formal theory. The concise treatment of the subject is maintained in this third edition covering all the major ideas: the wave equation, the diffusion equation, the Laplace equation, and the advection equation on bounded and unbounded domains. Methods include eigenfunction expansions, integral transforms, and characteristics. In this third edition, text remains intimately tied to applications in heat transfer, wave motion, biological systems, and a variety other topics in pure and applied science. The text offers flexibility to instructors who, for example, may wish to insert topics from biology or numerical methods at any time in the course. The exposition is presented in a friendly, easy-to-read, style, with mathematical ideas motivated from physical problems. Many exercises and worked e...

  6. Applied plasma physics

    International Nuclear Information System (INIS)

    Applied Plasma Physics is a major sub-organizational unit of the Magnetic Fusion Energy (MFE) Program. It includes Fusion Plasma Theory and Experimental Plasma Research. The Fusion Plasma Theory group has the responsibility for developing theoretical-computational models in the general areas of plasma properties, equilibrium, stability, transport, and atomic physics. This group has responsibility for giving guidance to the mirror experimental program. There is a formal division of the group into theory and computational; however, in this report the efforts of the two areas are not separated since many projects have contributions from members of both. Under the Experimental Plasma Research Program we are developing a neutral-beam source, the intense, pulsed ion-neutral source (IPINS), for the generation of a reversed-field configuration on 2XIIB. We are also studying the feasibility of using certain neutron-detection techniques as plasma diagnostics in the next generation of thermonuclear experiments

  7. Applied statistical thermodynamics

    CERN Document Server

    Lucas, Klaus

    1991-01-01

    The book guides the reader from the foundations of statisti- cal thermodynamics including the theory of intermolecular forces to modern computer-aided applications in chemical en- gineering and physical chemistry. The approach is new. The foundations of quantum and statistical mechanics are presen- ted in a simple way and their applications to the prediction of fluid phase behavior of real systems are demonstrated. A particular effort is made to introduce the reader to expli- cit formulations of intermolecular interaction models and to show how these models influence the properties of fluid sy- stems. The established methods of statistical mechanics - computer simulation, perturbation theory, and numerical in- tegration - are discussed in a style appropriate for newcom- ers and are extensively applied. Numerous worked examples illustrate how practical calculations should be carried out.

  8. Academic training: Applied superconductivity

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 17, 18, 19 January from 11.00 to 12.00 hrs Council Room, Bldg 503 Applied Superconductivity : Theory, superconducting Materials and applications E. PALMIERI/INFN, Padova, Italy When hearing about persistent currents recirculating for several years in a superconducting loop without any appreciable decay, one realizes that we are dealing with a phenomenon which in nature is the closest known to the perpetual motion. Zero resistivity and perfect diamagnetism in Mercury at 4.2 K, the breakthrough during 75 years of several hundreds of superconducting materials, the revolution of the "liquid Nitrogen superconductivity"; the discovery of still a binary compound becoming superconducting at 40 K and the subsequent re-exploration of the already known superconducting materials: Nature discloses drop by drop its intimate secrets and nobody can exclude that the last final surprise must still come. After an overview of phenomenology and basic theory of superconductivity, the lectures for this a...

  9. Applied hydraulic transients

    CERN Document Server

    Chaudhry, M Hanif

    2014-01-01

    This book covers hydraulic transients in a comprehensive and systematic manner from introduction to advanced level and presents various methods of analysis for computer solution. The field of application of the book is very broad and diverse and covers areas such as hydroelectric projects, pumped storage schemes, water-supply systems, cooling-water systems, oil pipelines and industrial piping systems. Strong emphasis is given to practical applications, including several case studies, problems of applied nature, and design criteria. This will help design engineers and introduce students to real-life projects. This book also: ·         Presents modern methods of analysis suitable for computer analysis, such as the method of characteristics, explicit and implicit finite-difference methods and matrix methods ·         Includes case studies of actual projects ·         Provides extensive and complete treatment of governed hydraulic turbines ·         Presents design charts, desi...

  10. Essays in applied microeconomics

    Science.gov (United States)

    Wang, Xiaoting

    In this dissertation I use Microeconomic theory to study firms' behavior. Chapter One introduces the motivations and main findings of this dissertation. Chapter Two studies the issue of information provision through advertisement when markets are segmented and consumers' price information is incomplete. Firms compete in prices and advertising strategies for consumers with transportation costs. High advertising costs contribute to market segmentation. Low advertising costs promote price competition among firms and improves consumer welfare. Chapter Three also investigates market power as a result of consumers' switching costs. A potential entrant can offer a new product bundled with an existing product to compensate consumers for their switching cost. If the primary market is competitive, bundling simply plays the role of price discrimination, and it does not dominate unbundled sales in the process of entry. If the entrant has market power in the primary market, then bundling also plays the role of leveraging market power and it dominates unbundled sales. The market for electric power generation has been opened to competition in recent years. Chapter Four looks at issues involved in the deregulated electricity market. By comparing the performance of the competitive market with the social optimum, we identify the conditions under which market equilibrium generates socially efficient levels of electric power. Chapter Two to Four investigate the strategic behavior among firms. Chapter Five studies the interaction between firms and unemployed workers in a frictional labor market. We set up an asymmetric job auction model, where two types of workers apply for two types of job openings by bidding in auctions and firms hire the applicant offering them the most profits. The job auction model internalizes the determination of the share of surplus from a match, therefore endogenously generates incentives for an efficient division of the matching surplus. Microeconomic

  11. Applied large eddy simulation.

    Science.gov (United States)

    Tucker, Paul G; Lardeau, Sylvain

    2009-07-28

    Large eddy simulation (LES) is now seen more and more as a viable alternative to current industrial practice, usually based on problem-specific Reynolds-averaged Navier-Stokes (RANS) methods. Access to detailed flow physics is attractive to industry, especially in an environment in which computer modelling is bound to play an ever increasing role. However, the improvement in accuracy and flow detail has substantial cost. This has so far prevented wider industrial use of LES. The purpose of the applied LES discussion meeting was to address questions regarding what is achievable and what is not, given the current technology and knowledge, for an industrial practitioner who is interested in using LES. The use of LES was explored in an application-centred context between diverse fields. The general flow-governing equation form was explored along with various LES models. The errors occurring in LES were analysed. Also, the hybridization of RANS and LES was considered. The importance of modelling relative to boundary conditions, problem definition and other more mundane aspects were examined. It was to an extent concluded that for LES to make most rapid industrial impact, pragmatic hybrid use of LES, implicit LES and RANS elements will probably be needed. Added to this further, highly industrial sector model parametrizations will be required with clear thought on the key target design parameter(s). The combination of good numerical modelling expertise, a sound understanding of turbulence, along with artistry, pragmatism and the use of recent developments in computer science should dramatically add impetus to the industrial uptake of LES. In the light of the numerous technical challenges that remain it appears that for some time to come LES will have echoes of the high levels of technical knowledge required for safe use of RANS but with much greater fidelity. PMID:19531503

  12. Essays in applied economics

    Science.gov (United States)

    Arano, Kathleen

    Three independent studies in applied economics are presented. The first essay looks at the US natural gas industrial sector and estimates welfare effects associated with the changes in natural gas regulatory policy over the past three decades. Using a disequilibrium model suited to the natural gas industry, welfare transfers and deadweight losses are calculated. Results indicate that deregulation policies, beginning with the NGPA of 1978, have caused the industry to become more responsive to market conditions. Over time, regulated prices converge toward the estimated equilibrium prices. As a result of this convergence, deadweight losses associated with regulation are also diminished. The second essay examines the discounted utility model (DU), the standard model used for intertemporal decision-making. Prior empirical studies challenge the descriptive validity of the model. This essay addresses the four main inconsistencies that have been raised: domain dependence, magnitude effects, time effects, and gain/loss asymmetries. These inconsistencies, however, may be the result of the implicit assumption of linear utility and not a failure of the DU model itself. In order to test this hypothesis, data was collected from in-class surveys of economics classes at Mississippi State University. A random effects model for panel data estimation which accounts for individual specific effects was then used to impute discount rates measured in terms of dollars and utility. All four inconsistencies were found to be present when the dollar measures were used. Using utility measures of the discount rate resolved the inconsistencies in some cases. The third essay brings together two perspectives in the study of religion and economics: modeling religious behavior using economic tools and variables, and modeling economic behavior using religious variables. A system of ordered probit equations is developed to simultaneously model religious activities and economic outcomes. Using data

  13. Nuclear power plant conference 2010 (NPC 2010): International conference on water chemistry of nuclear reactor systems and 8th International radiolysis, electrochemistry and materials performance workshop

    International Nuclear Information System (INIS)

    The Nuclear Plant Chemistry Conference was held in Quebec City, Quebec, Canada on October 3-7, 2010. It was hosted by the Canadian Nuclear Society and was held in Canada for the first time. This international event hosted over 300 attendees, two thirds from outside of Canada, mostly from Europe and and Far East. The conference is formally known as the International Conference on Water Chemistry of Nuclear Reactor Systems and is the 15th of a series that began in 1977 in Bournemouth, UK. The conference focussed on the latest developments in the science and technology of water chemistry control in nuclear reactor systems. Utility scientists, engineers and operations people met their counterparts from research institutes, service organizations and universities to address the challenges of chemistry control and degradation management of their complex and costly plants for the many decades that they are expected to operate. Following the four day conference, the 8th International Radiolysis, Electrochemistry and Materials Performance Workshop was held as associated, but otherwise free-standing event on Friday, October 8, 2010. It was also well attended and the primary focus was the effect of radiation on corrosion. When asked about the importance of chemistry in operating nuclear power plants, the primary organizers summarized it in the following statement: 'Once a nuclear plant is in operation, chemistry improvement is the only way to increase the longevity of the plant and its equipment'. The organisers of the 2010 Workshop and the NPC 2010 conference decided that these two events would be held consecutively, as previous, but for the first time the organization and registration would be shared, which proved to be a winning combination by the attendance.

  14. Electrochemistry of glucose oxidase on modified carbon nanotubes%葡萄糖氧化酶在修饰碳纳米管上的电化学

    Institute of Scientific and Technical Information of China (English)

    王佳; 李俊华; 周健

    2014-01-01

    Glucose oxidase (GOx) was immobilized on the electrode surface of multi-walled carbon nanotubes, amino functionalized carbon nanotubes (AMWNTs)and carboxyl functionalized carbon nanotubes (MWNTs-COOH). Electrochemical measurements indicated that the formal potentials of GOx immobilized on AMWNTs and MWNTs-COOH did not change, but their peak currents were improved. The peak current of GOx immobilized on AMWNTs was four times larger than that immobilized on MWNTs. The electrochemistry behavior of Nafion/GOx-AMWNTs/GC electrode were further characterized. The results indicated that GOx immobilized on AMWNTs could undergo a direct quasi-reversible electrochemical reaction and show good stability. Amino-functionalized electrodes could significantly improve the performance of GOx-based biofuel cells.%将葡萄糖氧化酶(GOx)分别固定在多壁碳纳米管(MWNT)、氨基化碳纳米管(AMWNTs)和羧基化碳纳米管(MWNTs-COOH)修饰的电极表面,电化学测量表明固定在羧基和氨基碳纳米管上的 GOx 式量电位基本没变,而峰电流得到了很大提高。尤其是氨基化碳纳米管上的GOx的峰电流是未功能化碳管上GOx的4倍多。进一步研究Nafion/GOx-AMWNTs/GC电极的电化学行为,发现固定在AMWNTs上的GOx可进行直接准可逆的氧化还原反应,而且固定在 AMWNTs 上的 GOx 有良好的稳定性。氨基改性碳纳米管电极载体材料有望显著提高 GOx生物燃料电池性能。

  15. Synthesis of 1,3-di(4-amino-1-pyridinium)propane ionic liquid functionalized graphene nanosheets and its application in direct electrochemistry of hemoglobin

    International Nuclear Information System (INIS)

    Highlights: ► 1,3-Di(4-amino-1-pyridinium)propane tetrafluoroborate ionic liquid was successfully synthesized. ► Ionic liquid modified graphene nanosheets were successfully prepared and fully characterized. ► Hb was immobilized on the as-prepared graphene–ionic liquid nanosheets. ► Direct electrochemistry of Hb was succeeded. ► Biocatalysis of Hb towards H2O2 was demonstrated, and was used in H2O2 determination. -- Abstract: 1,3-Di(4-amino-1-pyridinium)propane tetrafluoroborate (DAPPT) ionic liquid was successfully synthesized, and was used as a modifier to functionalize graphene nanosheets through covalent binding of amino groups and epoxy groups in an alkaline solution. The as-prepared graphene-DAPPT nanosheets (Gr-DAPPT) were confirmed with transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/vis and FTIR spectroscopy. A biocompatible platform based on Gr-DAPPT was constructed for the immobilization of hemoglobin (Hb) through a cross-linking step with chitosan and glutaraldehyde. The direct electron transfer and bioelectrocatalytic reaction of Hb immobilized on Gr-DAPPT surface were achieved. A pair of reversible redox peaks of hemoglobin was observed, and bioelectrocatalytic activity toward the reduction of H2O2 was also demonstrated, displaying a potential application for the fabrication of novel biosensors to sense H2O2. Such results indicated that Gr-DAPPT based interface would be a promising platform for biomacromolecular immobilization and biosensor preparation

  16. Free-polymer controlling morphology of {alpha}-MoO{sub 3} nanobelts by a facile hydrothermal synthesis, their electrochemistry for hydrogen evolution reactions and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Sinaim, Hathai [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Ham, Dong Jin; Lee, Jae Sung [Eco-friendly Catalysis and Energy Laboratory (NRL), Department of Chemical Engineering, School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); Phuruangrat, Anukorn, E-mail: phuruangrat@hotmail.com [Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thongtem, Somchai [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun, E-mail: ttpthongtem@yahoo.com [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2012-03-05

    Highlights: Black-Right-Pointing-Pointer MoO{sub 3} nanobelts as an n-type semiconducting material. Black-Right-Pointing-Pointer It was successfully synthesized by a facile hydrothermal reaction. Black-Right-Pointing-Pointer A promising material with 3.75 eV band gap for hydrogen evolution reaction (HER). - Abstract: Orthorhombic molybdenum oxide ({alpha}-MoO{sub 3}) nanobelts were successfully synthesized by the 100-180 Degree-Sign C and 2-20 h hydrothermal reactions of (NH{sub 4}){sub 6}Mo{sub 7}O{sub 24}{center_dot}4H{sub 2}O solutions containing 15 ml 2 M acid (HNO{sub 3}, H{sub 2}SO{sub 4} or HCl) with no surfactant and template adding. These products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, and electron microscopy (EM). In the present research, the product synthesized by the 180 Degree-Sign C and 20 h hydrothermal reaction of the solution containing HNO{sub 3} was {alpha}-MoO{sub 3} nanobelts with >10 {mu}m long and <200 nm wide. Electrochemistry for hydrogen evolution reactions (HER) and optical properties of the as-synthesized {alpha}-MoO{sub 3} nanobelts were characterized by linear sweep voltammetry (LSV) and Tafel plot, including UV-vis and photoluminescence (PL) spectroscopy. These imply that {alpha}-MoO{sub 3} nanobelts show satisfied performance for HER, with the 3.75 eV direct allowed band gap (E{sub g}) due to the charged transition of O{sub 2p} {yields} Mo{sub 4d}, including the emission of 437 nm wavelength at room temperature.

  17. Imidazoline derivative templated synthesis of broccoli-like Bi2S3 and its electrocatalysis towards the direct electrochemistry of hemoglobin.

    Science.gov (United States)

    Chen, Xiaoqian; Wang, Qingxiang; Wang, Liheng; Gao, Feng; Wang, Wei; Hu, Zhengshui

    2015-04-15

    A broccoli-like bismuth sulfide (bBi2S3) was synthesized via a solvothermal method using a self-made imidazoline derivative of 2-undecyl-1-dithioureido-ethyl-imidazoline as the soft template. The morphology and chemical constitution of the product were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Electrochemical characterization experiments show that the bBi2S3 has the higher specific surface area and standard heterogeneous electron transfer rate constant than the rod-like Bi2S3 (rBi2S3). Hemoglobin (Hb) was then chosen as a protein model to investigate the electrocatalytic property of the synthesized bBi2S3. The results show that Hb entrapped in the composite film of chitosan and bBi2S3 displays an excellent direct electrochemistry, and retains its biocatalytic activity toward the electro-reduction of hydrogen peroxide. The current response in the amperometry shows a linear response to H2O2 concentrations in the range from 0.4 to 4.8µM with high sensitivity (444µAmM(-1)) and low detection limit (0.096µM). The Michaelis-Menten constant (KM(app)) of the fabricated bioelectrode for H2O2 was determined as low as 1µM. These results demonstrate that the synthesized bBi2S3 offers a new path for the immobilization of redox-active protein and the construction of the third-generation biosensors. PMID:25437355

  18. Designer electrode interfaces simultaneously comprising three different metal nanoparticle (Au, Ag, Pd)/carbon microsphere/carbon nanotube composites: progress towards combinatorial electrochemistry.

    Science.gov (United States)

    Dai, Xuan; Wildgoose, Gregory G; Compton, Richard G

    2006-11-01

    In this report gold, silver and palladium metal nanoparticles are separately supported on glassy carbon microspheres (GCM) using bulk electroless deposition techniques to produce three different materials labelled as GCM-Au, GCM-Ag and GCM-Pd respectively. These three materials are then combined together into a composite film on a glassy carbon (GC) electrode surface using multiwalled carbon nanotubes (MWCNTs). The MWCNTs serve to not only mechanically support this composite film as a "binder" but they also help to "wire up" each modified GCM to the underlying substrate. The intelligently designed structure of this electrode interface allows this single modified electrode to simultaneously behave as if it were a macrodisc electrode constructed of gold, silver or palladium, whilst using only a fraction of the equivalent amount of these precious metals. Furthermore this unique structure allows the possibility of combinatorial electrochemistry to be realised using a relatively facile electrode construction which avoids the problems of alloy formation, co-deposition and the formation of bimetallic species. For instance a mixture of several different analytes, which can each only be detected on a different specific substrate, can simultaneously be determined using one electrode in a single voltammetric experiment! Alternatively a substrate could undergo electrocatalytic reactions on one substrate, whilst the products, and hence the progress of this reaction, can be studied at a different substrate simultaneously at the same electrode surface. Proof-of-concept examples are presented herein and the designer electrode interface is shown to produce analytical responses to model target analytes such as hydrazine, bromide and thallium(I) ions that are comparable, if not better, than those obtained at metal macrodisc electrodes and even at other state-of-the-art nanoparticle modified electrodes. PMID:17066193

  19. Amperometric carbohydrate antigen 19-9 immunosensor based on three dimensional ordered macroporous magnetic Au film coupling direct electrochemistry of horseradish peroxidase

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Three dimensional ordered macroporous magnetic electrode was newly used in electrochemical immunosensor. • The large surface area of macroporous magnetic electrode could improve the immobilized amount of antibody. • Au nanoparticles functionalized SBA-15 was used to immobilize enzyme labeled Ab2 and enzyme. • Macroporous magnetic electrode and Au nanoparticles composite facilitated the direct electron transfer of enzyme. • The immunoassay avoided adding electron transfer mediator, simplifying the procedure. - Abstract: A sandwich-type electrochemical immunosensor for the detection of carbohydrate antigen 19-9 (CA 19-9) antigen based on the immobilization of primary antibody (Ab1) on three dimensional ordered macroporous magnetic (3DOMM) electrode, and the direct electrochemistry of horseradish peroxidase (HRP) that was used as both the label of secondary antibody (Ab2) and the blocking reagent. The 3DOMM electrode was fabricated by introducing core–shell Au–SiO2@Fe3O4 nanospheres onto the surface of three dimensional ordered macroporous (3DOM) Au electrode via the application of an external magnet. Au nanoparticles functionalized SBA-15 (Au@SBA-15) was conjugated to the HRP labeled secondary antibody (HRP-Ab2) through the Au–SH or Au–NH3+ interaction, and HRP was also used as the block reagent. The formation of antigen–antibody complex made the combination of Au@SBA-15 and 3DOMM exhibit remarkable synergistic effects for accelerating direct electron transfer (DET) between HRP and the electrode. Under the optimal conditions, the DET current signal increased proportionally to CA 19-9 concentration in the range of 0.05 to 15.65 U mL−1 with a detection limit of 0.01 U mL−1. Moreover, the immunosensor showed high selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained

  20. Amperometric carbohydrate antigen 19-9 immunosensor based on three dimensional ordered macroporous magnetic Au film coupling direct electrochemistry of horseradish peroxidase

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qi [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Chen, Xiaojun, E-mail: chenxj_njut@126.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); Tang, Yin [Zhangjiagang Hospital of Traditional Chinese Medicine, Zhangjiagang 215600 (China); Ge, Lingna; Guo, Buhua [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Yao, Cheng, E-mail: yaochengnjut@163.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China)

    2014-03-01

    Highlights: • Three dimensional ordered macroporous magnetic electrode was newly used in electrochemical immunosensor. • The large surface area of macroporous magnetic electrode could improve the immobilized amount of antibody. • Au nanoparticles functionalized SBA-15 was used to immobilize enzyme labeled Ab₂ and enzyme. • Macroporous magnetic electrode and Au nanoparticles composite facilitated the direct electron transfer of enzyme. • The immunoassay avoided adding electron transfer mediator, simplifying the procedure. Abstract: A sandwich-type electrochemical immunosensor for the detection of carbohydrate antigen 19-9 (CA 19-9) antigen based on the immobilization of primary antibody (Ab₁) on three dimensional ordered macroporous magnetic (3DOMM) electrode, and the direct electrochemistry of horseradish peroxidase (HRP) that was used as both the label of secondary antibody (Ab₂) and the blocking reagent. The 3DOMM electrode was fabricated by introducing core–shell Au–SiO₂@Fe₃O₄ nanospheres onto the surface of three dimensional ordered macroporous (3DOM) Au electrode via the application of an external magnet. Au nanoparticles functionalized SBA-15 (Au@SBA-15) was conjugated to the HRP labeled secondary antibody (HRP-Ab₂) through the Au–SH or Au–NH₃⁺ interaction, and HRP was also used as the block reagent. The formation of antigen–antibody complex made the combination of Au@SBA-15 and 3DOMM exhibit remarkable synergistic effects for accelerating direct electron transfer (DET) between HRP and the electrode. Under the optimal conditions, the DET current signal increased proportionally to CA 19-9 concentration in the range of 0.05 to 15.65 U mL⁻¹ with a detection limit of 0.01 U mL⁻¹. Moreover, the immunosensor showed high selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained from

  1. Electrochemistry, a technique to prepare redox nano-structured composite materials (polymer/nano-particles) - Characterizations - Applications; L'electrochimie, un outil pour elaborer des materiaux composites redox nanostructures (polymere/nanoparticules) - Caracterisations - Applications

    Energy Technology Data Exchange (ETDEWEB)

    Chardon-Noblat, S. [Grenoble-1 Univ. Joseph Fourier, Lab. d' Electrochimie Organique et de Photochimie Redox, UMR 5630, Institut de Chimie Moleculaire de Grenoble, FR CNRS 2607, 38 - Grenoble (France)

    2006-07-01

    In this work is presented at first the preparation by an electrochemical way of bi functional nano-structured composite materials. It is shown that with the pulsed electrolysis techniques, it is possible to obtain metallic particles whose size and organization are controlled at the nano-scopic scale in redox matrices. Then, are presented the physico-chemical characterizations of these nano-objects (coupled in situ or ex situ at the electrochemistry). The first results relative to the catalytic activation of CO{sub 2} with these materials used as composite cathodes are indicated. (O.M.)

  2. Direct electrochemistry of hemoglobin and biosensing for hydrogen peroxide using a film containing silver nanoparticles and poly(amidoamine) dendrimer.

    Science.gov (United States)

    Baccarin, Marina; Janegitz, Bruno C; Berté, Rodrigo; Vicentini, Fernando Campanhã; Banks, Craig E; Fatibello-Filho, Orlando; Zucolotto, Valtencir

    2016-01-01

    A new architecture for a biosensor is proposed using a glassy carbon electrode (GCE) modified with hemoglobin (Hb) and silver nanoparticles (AgNPs) encapsulated in poly(amidoamine) dendrimer (PAMAM). The biosensors were characterized using ultraviolet-visible spectroscopy, ζ-potential and cyclic voltammetry to investigate the interactions between Hb, AgNPs and the PAMAM film. The biosensor exhibited a well-defined cathodic peak attributed to reduction of the Fe(3+) present in the heme group in Hb, as revealed by cyclic voltammetry in the presence of O2. An apparent heterogeneous electron transfer rate of 4.1s(-1) was obtained. The Hb-AgNPs-PAMAM/GCE third generation biosensor was applied in the amperometric determination of hydrogen peroxide over the linear range from 6.0 × 10(-6) to 9.1 × 10(-5)mol L(-1) with a detection limit of 4.9 × 1 0(-6)mol L(-1). The proposed method can be extended to immobilize and evaluate the direct electron transfer of other redox enzymes. PMID:26478291

  3. Applied Ethics in Nowadays Society

    OpenAIRE

    Tomita CIULEI

    2013-01-01

    This special issue is dedicated to Nowadays Applied Ethics in Society, and falls in the field of social sciences and humanities, being hosted both theoretical approaches and empirical research in various areas of applied ethics. Applied ethics analyzes of a series of morally concrete situations of social or professional practice in order to make / adopt decisions. In the field of applied ethics are integrated medical ethics, legal ethics, media ethics, professional ethics, environmental ethic...

  4. The Routledge Applied Linguistics Reader

    Science.gov (United States)

    Wei, Li, Ed.

    2011-01-01

    "The Routledge Applied Linguistics Reader" is an essential collection of readings for students of Applied Linguistics. Divided into five sections: Language Teaching and Learning, Second Language Acquisition, Applied Linguistics, Identity and Power and Language Use in Professional Contexts, the "Reader" takes a broad interpretation of the subject…

  5. Direct electrochemistry with enhanced electrocatalytic activity of hemoglobin in hybrid modified electrodes composed of graphene and multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •A graphene and multi-walled carbon nanotubes nanocomposite was prepared. •Hemoglobin and nanocomposite modified carbon ionic liquid electrode was fabricated. •Direct electrochemistry of hemoglobin was realized on the modified electrode. •Bioelectrocatalysis towards the reduction of different substrates was enhanced. -- Abstract: A graphene (GR) and multi-walled carbon nanotubes (MWCNT) hybrid was prepared and modified on a 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on GR-MWCNT/CILE surface with Nafion as the film forming material and the modified electrode was denoted as Nafion/Hb-GR-MWCNT/CILE. Spectroscopic results revealed that Hb molecules retained its native structure in the GR-MWCNT hybird. Electrochemical behaviors of Hb were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks obtained, which indicated that direct electron transfer of Hb was realized in the hybrid modified electrode. The result could be attributed to the synergistic effects of GR-MWCNT hybrid with enlarged surface area and improved conductivity through the formation of a three-dimensional network. Electrochemical parameters of the immobilized Hb on the electrode surface were further calculated with the results of the electron transfer number (n) as 1.03, the charge transfer coefficient (a) as 0.58 and the electron-transfer rate constant (ks) as 0.97 s−1. The Hb modified electrode showed good electrocatalytic ability toward the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.05 to 38.0 mmol L−1 with a detection limit of 0.0153 mmol L−1 (3σ), H2O2 in the concentration range from 0.1 to 516.0 mmol L−1 with a detection limit of 34.9 nmol/L (3σ) and NaNO2 in the concentration range from 0.5 to 650.0 mmol L−1 with a detection limit of 0.282 μmol L−1 (3σ). So the proposed electrode had the

  6. Direct electrochemistry with enhanced electrocatalytic activity of hemoglobin in hybrid modified electrodes composed of graphene and multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei, E-mail: swyy26@hotmail.com [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 China (China); College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Cao, Lili; Deng, Ying; Gong, Shixing [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Shi, Fan; Li, Gaonan; Sun, Zhenfan [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 China (China)

    2013-06-05

    Graphical abstract: -- Highlights: •A graphene and multi-walled carbon nanotubes nanocomposite was prepared. •Hemoglobin and nanocomposite modified carbon ionic liquid electrode was fabricated. •Direct electrochemistry of hemoglobin was realized on the modified electrode. •Bioelectrocatalysis towards the reduction of different substrates was enhanced. -- Abstract: A graphene (GR) and multi-walled carbon nanotubes (MWCNT) hybrid was prepared and modified on a 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on GR-MWCNT/CILE surface with Nafion as the film forming material and the modified electrode was denoted as Nafion/Hb-GR-MWCNT/CILE. Spectroscopic results revealed that Hb molecules retained its native structure in the GR-MWCNT hybird. Electrochemical behaviors of Hb were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks obtained, which indicated that direct electron transfer of Hb was realized in the hybrid modified electrode. The result could be attributed to the synergistic effects of GR-MWCNT hybrid with enlarged surface area and improved conductivity through the formation of a three-dimensional network. Electrochemical parameters of the immobilized Hb on the electrode surface were further calculated with the results of the electron transfer number (n) as 1.03, the charge transfer coefficient (a) as 0.58 and the electron-transfer rate constant (k{sub s}) as 0.97 s{sup −1}. The Hb modified electrode showed good electrocatalytic ability toward the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.05 to 38.0 mmol L{sup −1} with a detection limit of 0.0153 mmol L{sup −1} (3σ), H{sub 2}O{sub 2} in the concentration range from 0.1 to 516.0 mmol L{sup −1} with a detection limit of 34.9 nmol/L (3σ) and NaNO{sub 2} in the concentration range from 0.5 to 650.0 mmol L{sup −1} with a detection limit of 0

  7. Applied Academics. Applied Mathematics: Drafting. Curriculum Bulletin VE-53.

    Science.gov (United States)

    Cincinnati Public Schools, OH. Div. of Student Services.

    This publication contains the Applied Mathematics Curriculum (Drafting) for grades 11 and 12 for the Cincinnati (Ohio) Public Schools. The curriculum is part of a larger program (the Applied Academics Program), which emphasizes the integration of mathematics and the language arts with vocational content. Included in the document is a description…

  8. A Review of Applied Mathematics

    OpenAIRE

    Ó Náraigh, Lennon; Ní Shúilleabháin, Aoibhinn

    2015-01-01

    Applied Mahtematics is a subject which deals with problmes arising inthe physical, life, and social sciences as well as in engineering and provides a broad body of knowledge for use in a wide spectrum of research and insdustry. Applied Mathematics is an important school subject which builds students' mathematical and problem solving skills. The subject has remained on the periphery of school time-tables and, without the commitment and enthusiasm of Applied Maths teachers, would likely be omit...

  9. Applied Ethics in Nowadays Society

    Directory of Open Access Journals (Sweden)

    Tomita CIULEI

    2013-12-01

    Full Text Available This special issue is dedicated to Nowadays Applied Ethics in Society, and falls in the field of social sciences and humanities, being hosted both theoretical approaches and empirical research in various areas of applied ethics. Applied ethics analyzes of a series of morally concrete situations of social or professional practice in order to make / adopt decisions. In the field of applied ethics are integrated medical ethics, legal ethics, media ethics, professional ethics, environmental ethics, business ethics etc. Classification-JEL: A23

  10. Applied probability and stochastic processes

    CERN Document Server

    Sumita, Ushio

    1999-01-01

    Applied Probability and Stochastic Processes is an edited work written in honor of Julien Keilson. This volume has attracted a host of scholars in applied probability, who have made major contributions to the field, and have written survey and state-of-the-art papers on a variety of applied probability topics, including, but not limited to: perturbation method, time reversible Markov chains, Poisson processes, Brownian techniques, Bayesian probability, optimal quality control, Markov decision processes, random matrices, queueing theory and a variety of applications of stochastic processes. The book has a mixture of theoretical, algorithmic, and application chapters providing examples of the cutting-edge work that Professor Keilson has done or influenced over the course of his highly-productive and energetic career in applied probability and stochastic processes. The book will be of interest to academic researchers, students, and industrial practitioners who seek to use the mathematics of applied probability i...

  11. Distributed computing applied applied to the identification of new drugs

    OpenAIRE

    Isea, Raul; Mayo, Rafael

    2010-01-01

    This work emphasizes the assets of implementing the distributed computing for the intensive use in computational science devoted to the search of new medicines that could be applied in public healthy problems.

  12. Principles for system level electrochemistry

    Science.gov (United States)

    Thaller, L. H.

    1986-01-01

    The higher power and higher voltage levels anticipated for future space missions have required a careful review of the techniques currently in use to preclude battery problems that are related to the dispersion characteristics of the individual cells. Not only are the out-of-balance problems accentuated in these larger systems, but the thermal management considerations also require a greater degree of accurate design. Newer concepts which employ active cooling techniques are being developed which permit higher rates of discharge and tighter packing densities for the electrochemical components. This paper will put forward six semi-independent principles relating to battery systems. These principles will progressively address cell, battery and finally system related aspects of large electrochemical storage systems.

  13. Electrochemistry and Storage Panel Report

    Science.gov (United States)

    Stedman, J. K.; Halpert, G.

    1984-01-01

    Design and performance requirements for electrochemical power storage systems are discussed and some of the approaches towards satisfying these constraints are described. Geosynchronous and low Earth orbit applications, radar type load constraints, and high voltage systems requirements are addressed. In addition, flywheel energy storage is discussed.

  14. Electrochemistry of Q-Graphene

    Science.gov (United States)

    Randviir, Edward P.; Brownson, Dale A. C.; Gómez-Mingot, Maria; Kampouris, Dimitrios K.; Iniesta, Jesús; Banks, Craig E.

    2012-09-01

    A newly synthesised type of graphene, Q-Graphene, has been physically and electrochemically characterised with Scanning and Transmission Electron Microscopy (SEM, TEM), X-ray Photoelectron Spectroscopy (XPS) and Cyclic Voltammetry (CV). Interpretation of SEM, TEM and XPS data reveal the material to consist of hollow carbon nanospheres of multi-layer graphene (viz. graphite), which exhibit a total oxygen content of ca. 36.0% (atomic weight via XPS). In addition to the carbon structures present, spherical magnesium oxide particles of ruthenium(iii) chloride and hexachloroiridate(iii), in addition to the biologically relevant and electroactive analytes, norepinephrine, β-nicotinamide adenine dinucleotide (NADH) and l-ascorbic acid. The electrochemical response of Q-Graphene is benchmarked against edge plane- and basal plane-pyrolytic graphite (EPPG and BPPG respectively), pristine graphene and graphite alternatives. Q-Graphene is found to exhibit fast electron transfer kinetics, likely due to its high proportion of folded edges and surface defects, exhibiting a response similar to that of EPPG - which exhibits fast electron transfer rates due to the high proportion of edge plane sites it possesses. Furthermore, we demonstrate that the specific oxygen content plays a pivotal role in dictating the observed electrochemical response, which is analyte dependant. Consequently there is potential for this new member of the graphene family to be beneficially utilised in various electrochemical applications.A newly synthesised type of graphene, Q-Graphene, has been physically and electrochemically characterised with Scanning and Transmission Electron Microscopy (SEM, TEM), X-ray Photoelectron Spectroscopy (XPS) and Cyclic Voltammetry (CV). Interpretation of SEM, TEM and XPS data reveal the material to consist of hollow carbon nanospheres of multi-layer graphene (viz. graphite), which exhibit a total oxygen content of ca. 36.0% (atomic weight via XPS). In addition to the carbon structures present, spherical magnesium oxide particles of ruthenium(iii) chloride and hexachloroiridate(iii), in addition to the biologically relevant and electroactive analytes, norepinephrine, β-nicotinamide adenine dinucleotide (NADH) and l-ascorbic acid. The electrochemical response of Q-Graphene is benchmarked against edge plane- and basal plane-pyrolytic graphite (EPPG and BPPG respectively), pristine graphene and graphite alternatives. Q-Graphene is found to exhibit fast electron transfer kinetics, likely due to its high proportion of folded edges and surface defects, exhibiting a response similar to that of EPPG - which exhibits fast electron transfer rates due to the high proportion of edge plane sites it possesses. Furthermore, we demonstrate that the specific oxygen content plays a pivotal role in dictating the observed electrochemical response, which is analyte dependant. Consequently there is potential for this new member of the graphene family to be beneficially utilised in various electrochemical applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr31823g

  15. CHEMISTRY, ELECTROCHEMISTRY, AND ELECTROCHEMICAL APPLICATIONS

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf; Bjerrum, Niels

    2009-01-01

    About 350 Papers Covering: Basics of Electrodes, Electrolytes, Cells, Batteries and Stacks, Measurement Techniques, Synthesis of Materials, Primary Batteries, Secondary Batteries, Supercapacitors, and Fuel Cells, Hydrogen Production and Storage, Photoelectrochemical Cells, Safety, Recycling, Port...

  16. Applications of ultrasound in electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Silva Martinez, Susana

    1997-10-01

    The effect of the ultrasound on electrochemical processes has been investigated employing a microelectrode within the cavitating media. Transient mass transport was strongly enhanced in the presence of ultrasound. High rates of mass transfer of up to 1.5 cm s-1 were observed. These high rates of mass transfer were attributed to two cavitation processes. First, bubble collapse at or near the solid-liquid interface with the consequent formation of a high speed liquid microjet directed at the electrode surface. Second, bubble motion near or within the diffusion layer or the electrode. Single current transients were also recorded at high time resolution. These single current transients were attributed to the short-time perturbation of the diffusion field of the microelectrode due to impacts of cavitation bubble collapse followed by a long time relaxation of the diffusion field back to the steady state. The influence of the ultrasonic source to electrode separation, temperature of the bulk solution, electrode potential and electrode size on the magnitude of current transients was also studied. All of these parameters affected markedly the magnitude of the current transients recorded at microelectrode in the presence of ultrasound. An alternative approach is presented to characterise fast heterogeneous electron transfer reactions employing ultrasound as a mass transport enhancement tool. Two innovative techniques, sampled-current voltammetry and sampled-mean current voltammetry, were developed during the course of this thesis. The technique of sample-current voltammetry reported values of the standard rate constant of heterogeneous electron transfer of up to 1.2 cm s-1 in the presence of ultrasound. This technique focuses on the electrochemical phenomena under investigation at the point of impact of the ultrasonic event, produced by asymmetric cavitation bubble collapse near the electrode surface. Bubble dynamics were also examined under the experimental conditions employed in the present study. The bubble behaviour was observed from the numerical solution of the RPNNP equation that describes the motion of a gas filled bubble in a homogeneous phase. This equation was solved numerically employing the Fourorder Runge-Kutta method. Finally, a preliminary study of surface process in the presence of ultrasound is presented. Erosion current events were recorded at high time solution. These current events were attributed to the reoxidation of the exposed metal as a result of cavitation events. This study shows that surface erosion can be electrochemically investigated in-situ withing a cavitating media. [Espanol] El efecto del ultrasonido en procesos electroquimicos ha sido investigado empleando un micro-electrodo dentro de un medio cavitante. El transporte de masa transitorio fue realzado fuertemente en la presencia de ultrasonido. Altos indices de la transferencia de masa de hasta 1.5 cm s-1 fueron observados. Estos altos indices de la transferencia de masa fueron atribuidos a dos procesos de la cavitacion. Primero, el colapso de la burbuja en/o cerca de la interfase solido-liquido con la formacion consiguiente de un microjet liquido de alta velocidad dirigido hacia la superficie del electrodo. En segundo lugar, movimiento de la burbuja cerca o dentro de la capa de difusion o del electrodo. Tambien se registraron los simples transitorios de corriente a una alta resolucion de tiempo. Estos transitorios simples de corriente fueron atribuidos a la perturbacion a corto plazo del campo de difusion del micro-electrodo debido a los impactos de cavitacion del colapso de la burbuja seguido por una relajacion de largo tiempo del campo de la difusion de nuevo al estado estable. La influencia de la fuente ultrasonica a la separacion del electrodo, la temperatura total de la solucion, el potencial del electrodo y el tamano del electrodo sobre la magnitud de transitorios de corriente tambien fue estudiada. Todos estos parametros afectaron marcadamente la magnitud de los transitorios de corriente registrados en el micro-electrodo en presencia del ultrasonido. Se presenta una opcion alternativa para caracterizar reacciones heterogeneas rapidas de transferencia del electron que empleando el ultrasonido como herramienta, de realce del transporte de masa. Dos tecnicas innovadoras, la voltametria corriente muestreada y la voltametria corriente-media muestreada, se desarrollaron durante el curso de esta tesis. La tecnica del voltammetria corriente de muestra senalo los valores del regimen estandar constante de la transferencia heterogenea del electron de hasta 1.2 centimetros s-1 en la presencia del ultrasonido. Esta tecnica se centra en los fenomenos electroquimicos bajo investigacion en el punto de impacto del acontecimiento ultrasonico, producido por colapso asimetrico de la burbuja de cavitacion cerca de la superficie del electrodo. Las dinamicas de la burbuja tambien fueron examinadas bajo las condiciones experimentales empleadas en el presente estudio. El comportamiento de la burbuja fue observado desde la solucion numerica de la ecuacion de RPNNP que describe el movimiento de una burbuja llena gas en una fase homogenea. Esta ecuacion fue resuelta numericamente empleando el metodo de cuarto orden de Runge-Kutta. Finalmente se presenta un estudio preliminar del proceso superficial en presencia del ultrasonido. Los eventos de erosion por corriente fueron registrados a una alta resolucion de tiempo. Estos eventos de corriente fueron atribuidos a la re-oxidacion del metal expuesto como resultado de eventos de cavitacion. Este estudio muestra que la erosion superficial puede ser investigada electroquimicamente in situ dentro del medio de cavitacion.

  17. Conversation Analysis in Applied Linguistics

    DEFF Research Database (Denmark)

    Kasper, Gabriele; Wagner, Johannes

    2014-01-01

    For the last decade, conversation analysis (CA) has increasingly contributed to several established fields in applied linguistics. In this article, we will discuss its methodological contributions. The article distinguishes between basic and applied CA. Basic CA is a sociological endeavor concerned...... been driven by applied work. After laying out CA's standard practices of data treatment and analysis, this article takes up the role of comparison as a fundamental analytical strategy and reviews recent developments into cross-linguistic and cross-cultural directions. The remaining article focuses...... on learning and development. In conclusion, we address some emerging themes in the relationship of CA and applied linguistics, including the role of multilingualism, standard social science methods as research objects, CA's potential for direct social intervention, and increasing efforts to complement CA...

  18. Shock Thermodynamic Applied Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Shock Thermodynamic Applied Research Facility (STAR) facility, within Sandia’s Solid Dynamic Physics Department, is one of a few institutions in the world with...

  19. Women in applied behavior analysis

    OpenAIRE

    McSweeney, Frances K.; Donahoe, Patricia; Swindell, Samantha

    2000-01-01

    The status of women in applied behavior analysis was examined by comparing the participation of women in the Journal of Applied Behavior Analysis (JABA) to their participation in three similar journals. For all journals, the percentage of articles with at least one female author, the percentage of authors who are female, and the percentage of articles with a female first author increased from 1978 to 1997. Participation by women in JABA was equal to or greater than participation by women in t...

  20. Applied statistical inference with MINITAB

    CERN Document Server

    Lesik, Sally

    2009-01-01

    Through clear, step-by-step mathematical calculations, Applied Statistical Inference with MINITAB enables students to gain a solid understanding of how to apply statistical techniques using a statistical software program. It focuses on the concepts of confidence intervals, hypothesis testing, validating model assumptions, and power analysis.Illustrates the techniques and methods using MINITABAfter introducing some common terminology, the author explains how to create simple graphs using MINITAB and how to calculate descriptive statistics using both traditional hand computations and MINITAB. Sh

  1. Applied medical statistics using SAS

    CERN Document Server

    Der, Geoff

    2012-01-01

    ""Each chapter in the book is well laid out, contains examples with SAS code, and ends with a concise summary. The chapters in the book contain the right level of information to use SAS to apply different statistical methods. … a good overview of how to apply in SAS 9.3 the many possible statistical analysis methods.""-Caroline Kennedy, Takeda Development Centre Europe Ltd., Statistical Methods for Medical Research, 2015""… a well-organized and thorough exploration of broad coverage in medical statistics. The book is an excellent reference of statistical methods

  2. Applied mathematics reviews, v.1

    CERN Document Server

    Anastassiou, George A

    2000-01-01

    Applied mathematics connects the mathematical theory to the reality by solving real world problems and shows the power of the science of mathematics, greatly improving our lives. Therefore it plays a very active and central role in the scientific world.This volume contains 14 high quality survey articles - incorporating original results and describing the main research activities of contemporary applied mathematics - written by top people in the field. The articles have been written in review style, so that the researcher can have a quick and thorough view of what is happening in the main subf

  3. Applied analysis and differential equations

    CERN Document Server

    Cârj, Ovidiu

    2007-01-01

    This volume contains refereed research articles written by experts in the field of applied analysis, differential equations and related topics. Well-known leading mathematicians worldwide and prominent young scientists cover a diverse range of topics, including the most exciting recent developments. A broad range of topics of recent interest are treated: existence, uniqueness, viability, asymptotic stability, viscosity solutions, controllability and numerical analysis for ODE, PDE and stochastic equations. The scope of the book is wide, ranging from pure mathematics to various applied fields such as classical mechanics, biomedicine, and population dynamics.

  4. Applying and extending Oracle Spatial

    CERN Document Server

    Simon Gerard Greener, Siva Ravada

    2013-01-01

    This book is an advanced practical guide to applying and extending Oracle Spatial.This book is for existing users of Oracle and Oracle Spatial who have, at a minimum, basic operational experience of using Oracle or an equivalent database. Advanced skills are not required.

  5. Toward an Applied Administrative Science.

    Science.gov (United States)

    Dunbar, Roger L. M.

    1983-01-01

    A study of 65 articles from the 1981 volumes of "Administrative Science Quarterly" and "Harvard Business Review," using smallest space analysis, found that the few studies adopting subjective (instead of objective) approaches to analyzing organizational change were most likely to provide a basis for an applied administrative science. (Author/RW)

  6. SEM in applied marketing research

    DEFF Research Database (Denmark)

    Sørensen, Bjarne Taulo; Tudoran, Ana Alina

    In this paper we discuss two SEM approaches: an exploratory structural equation modelling based on a more liberalised and inductive philosophy versus the classical SEM based on the traditional hypothetical-deductive approach. We apply these two modelling techniques to data from a consumer survey ...

  7. Applied Linguistics Research on Asianness

    Science.gov (United States)

    Kobayashi, Yoko

    2011-01-01

    As China is increasingly occupying the world's attention, its explosively expanding economical and political clout has also been felt in the applied linguistics domain, with the discussion on China's/Chinese language issues growing by leaps and bounds (e.g. China's English education policies, Chinese language classes in the West). Amid the world's…

  8. Modern applied U-statistics

    CERN Document Server

    Kowalski, Jeanne

    2008-01-01

    A timely and applied approach to the newly discovered methods and applications of U-statisticsBuilt on years of collaborative research and academic experience, Modern Applied U-Statistics successfully presents a thorough introduction to the theory of U-statistics using in-depth examples and applications that address contemporary areas of study including biomedical and psychosocial research. Utilizing a "learn by example" approach, this book provides an accessible, yet in-depth, treatment of U-statistics, as well as addresses key concepts in asymptotic theory by integrating translational and cross-disciplinary research.The authors begin with an introduction of the essential and theoretical foundations of U-statistics such as the notion of convergence in probability and distribution, basic convergence results, stochastic Os, inference theory, generalized estimating equations, as well as the definition and asymptotic properties of U-statistics. With an emphasis on nonparametric applications when and where applic...

  9. Applied survival analysis using R

    CERN Document Server

    Moore, Dirk F

    2016-01-01

    Applied Survival Analysis Using R covers the main principles of survival analysis, gives examples of how it is applied, and teaches how to put those principles to use to analyze data using R as a vehicle. Survival data, where the primary outcome is time to a specific event, arise in many areas of biomedical research, including clinical trials, epidemiological studies, and studies of animals. Many survival methods are extensions of techniques used in linear regression and categorical data, while other aspects of this field are unique to survival data. This text employs numerous actual examples to illustrate survival curve estimation, comparison of survivals of different groups, proper accounting for censoring and truncation, model variable selection, and residual analysis. Because explaining survival analysis requires more advanced mathematics than many other statistical topics, this book is organized with basic concepts and most frequently used procedures covered in earlier chapters, with more advanced topics...

  10. The MRC Applied Psychology Unit

    OpenAIRE

    2003-01-01

    This transcript considers the origins and impact of the MRC Applied Psychology Unit’s work from 1944 to 1998. Psychologists, clinicians, and industrial, ergonomic and occupational psychologists discuss the evolution of work from quite narrow postwar industrial and military concerns to more recent applications in, for example, ageing, dyslexia, depression, form design, information and semantics. Those who contributed included Professor Alan Baddeley, Dr Philip Barnard, Dr Ivan Brown, Professor...

  11. Geostatistics applied to uranium mineral

    International Nuclear Information System (INIS)

    The concepts of geostatistics are particularly introduced in the field of regionalized variables theory in order to apply them to the reserves estimation problem, since through this theory we can study the structural characteristics of the variable under consideration. So, before the starting of mine works we might suggest the geostatistic study of the deposit, in order to obtain an estimation of the reserves. Finally, a geostatistic study of the sedimentary type uranium deposit, called ''La Coma'', is realized

  12. Three essays on applied economics

    OpenAIRE

    Li, Yunrong

    2014-01-01

    This thesis focuses on the application of empirical research methods to different economic topics. The first chapter examines production effects of subsidies with different characteristics. The second chapter evaluates the impact of an oldage pension program on the welfare of the recipient’s family members. The third chapter applies an income inequality model to study the influence of differences in citation practices across scientific fields on the overall citation inequality. ...

  13. Applied Estimation of Mobile Environments

    OpenAIRE

    Weekly, Kevin Pu

    2014-01-01

    For many research problems, controlling and estimating the position of the mobile elements within an environment is desired. Realistic mobile environments are unstructured, but share a set of common features, such as position, speed, and constraints on mobility. To estimate within these real-world environments requires careful selection of the best-suited estimation tools and software and hardware technologies. This dissertation discusses the design and implementation of applied estimation...

  14. Three Essays on Applied Microeconomics

    OpenAIRE

    Cao, Yang

    2016-01-01

    In these essays, I study the following three topics in Applied Microeconomics using datasets of China: (1) The impact of political movements in the first thirty years of People's Republic of China on the intergenerational and multigenerational transmission of education; (2) The relationship between health insurance and households' consumption; (3) The effect of health insurance on out-of-pocket medical expenditures. The first chapter investigates the effect of family class origin on education...

  15. Matrix methods applied linear algebra

    CERN Document Server

    Bronson, Richard

    2008-01-01

    Matrix Methods: Applied Linear Algebra, 3e, as a textbook, provides a unique and comprehensive balance between the theory and computation of matrices. The application of matrices is not just for mathematicians. The use by other disciplines has grown dramatically over the years in response to the rapid changes in technology. Matrix methods is the essence of linear algebra and is what is used to help physical scientists; chemists, physicists, engineers, statisticians, and economists solve real world problems.* Applications like Markov chains, graph theory and Leontief Models are placed i

  16. Statistical tests applied in tourism

    Directory of Open Access Journals (Sweden)

    Petcu, N.

    2011-01-01

    Full Text Available Being given the conditions of an ever increasing competition between the offerers of touristic products at internal and international level, an important factor is represented by the formation of stable customers who should also ensure the promotion of the touristic product among the possible clients on different markets. This supposes the achievement of some high quality touristic services which should generate favorable and long-lasting impressions. The paper is meant to build an analysis model of the data resulted from sounding research based by applying statistical tests.

  17. Applying quantum principles to psychology

    International Nuclear Information System (INIS)

    This article starts out with a detailed example illustrating the utility of applying quantum probability to psychology. Then it describes several alternative mathematical methods for mapping fundamental quantum concepts (such as state preparation, measurement, state evolution) to fundamental psychological concepts (such as stimulus, response, information processing). For state preparation, we consider both pure states and densities with mixtures. For measurement, we consider projective measurements and positive operator valued measurements. The advantages and disadvantages of each method with respect to applications in psychology are discussed. (paper)

  18. Epidemiology applied to health physics

    International Nuclear Information System (INIS)

    The technical program of the mid-year meeting of the Health Physics Society, entitled Epidemiology Applied to Health physics, was developed to meet three objectives: (1) give health physicists a deeper understanding of the basics of epidemiological methods and their use in developing standards, regulations, and criteria and in risk assessment; (2) present current reports on recently completed or on-going epidemiology studies; and (3) encourage greater interaction between the health physics and epidemiology disciplines. Included are studies relating methods in epidemiology to radiation protection standards, risk assessment from exposure to bone-seekers, from occupational exposures in mines, mills and nuclear facilities, and from radioactivity in building materials

  19. Workshop applied antineutrino physics 2007

    International Nuclear Information System (INIS)

    The 'Applied Antineutrino Physics 2007' workshop is the fourth international meeting devoted to the opening of the neutrino physics to more applied fields, such as geophysics and geochemistry, nuclear industry, as well as the nonproliferation. This meeting highlights the world efforts already engaged to exploit the single characteristics of the neutrinos for the control of the production of plutonium in the civil nuclear power reactor. The potential industrial application of the measurement of the thermal power of the nuclear plants by the neutrinos is also approached. earth neutrinos were for the first time highlighted in 2002 by the KamLAND experiment. Several international efforts are currently underway to use earth neutrinos to reveal the interior of the Earth. This meeting is an opportunity to adapt the efforts of detection to the real needs of geophysicists and geochemists (sources of radiogenic heat, potassium in the court, feathers.) Finally more futuristic topics such as the detection of nuclear explosions, of low powers, are also discussed. This document gathers only the slides of the presentations

  20. Workshop applied antineutrino physics 2007

    Energy Technology Data Exchange (ETDEWEB)

    Akiri, T.; Andrieu, B.; Anjos, J.; Argyriades, J.; Barouch, G.; Bernstein, A.; Bersillon, O.; Besida, O.; Bowden, N.; Cabrera, A.; Calmet, D.; Collar, J.; Cribier, M.; Kerret, H. de; Meijer, R. de; Dudziak, F.; Enomoto, S.; Fallot, M.; Fioni, G.; Fiorentini, G.; Gale, Ph.; Georgadze, A.; Giot, L.; Gonin, M.; Guillon, B.; Henson, C.; Jonkmans, G.; Kanamaru, S.; Kawasaki, T.; Kornoukhov, V.; Lasserre, Th.; Learned, J.G.; Lefebvre, J.; Letourneau, A.; Lhillier, D.; Lindner, M.; Lund, J.; Mantovani, F.; Mcdonough, B.; Mention, G.; Monteith, A.; Motta, D.; Mueller, Th.; Oberauer, L.; Obolensky, M.; Odrzywolek, A.; Petcov, S.; Porta, A.; Queval, R.; Reinhold, B.; Reyna, D.; Ridikas, D.; Sadler, L.; Schoenert, St.; Sida, J.L.; Sinev, V.; Suekane, F.; Suvorov, Y.; Svoboda, R.; Tang, A.; Tolich, N.; Tolich, K.; Vanka, S.; Vignaud, D.; Volpe, Ch.; Wong, H

    2007-07-01

    The 'Applied Antineutrino Physics 2007' workshop is the fourth international meeting devoted to the opening of the neutrino physics to more applied fields, such as geophysics and geochemistry, nuclear industry, as well as the nonproliferation. This meeting highlights the world efforts already engaged to exploit the single characteristics of the neutrinos for the control of the production of plutonium in the civil nuclear power reactor. The potential industrial application of the measurement of the thermal power of the nuclear plants by the neutrinos is also approached. earth neutrinos were for the first time highlighted in 2002 by the KamLAND experiment. Several international efforts are currently underway to use earth neutrinos to reveal the interior of the Earth. This meeting is an opportunity to adapt the efforts of detection to the real needs of geophysicists and geochemists (sources of radiogenic heat, potassium in the court, feathers.) Finally more futuristic topics such as the detection of nuclear explosions, of low powers, are also discussed. This document gathers only the slides of the presentations.

  1. Taxonomic Evidence Applying Intelligent Information Taxonomic Evidence Applying Intelligent Information

    Directory of Open Access Journals (Sweden)

    Félix Anibal Vallejos

    2005-12-01

    Full Text Available The Numeric Taxonomy aims to group operational taxonomic units in clusters (OTUs or taxons or taxa, using the denominated structure analysis by means of numeric methods. These clusters that constitute families are the purpose of this series of projects and they emerge of the structural analysis, of their phenotypical characteristic, exhibiting the relationships in terms of grades of similarity of the OTUs, employing tools such as i the Euclidean distance and ii nearest neighbor techniques. Thus taxonomic evidence is gathered so as to quantify the similarity for each pair of OTUs (pair-group method obtained from the basic data matrix and in this way the significant concept of spectrum of the OTUs is introduced, being based the same one on the state of their characters. A new taxonomic criterion is thereby formulated and a new approach to Computational Taxonomy is presented, that has been already employed with reference to Data Mining, when apply of Machine Learning techniques, in particular to the C4.5 algorithms, created by Quinlan, the degree of efficiency achieved by the TDIDT family's algorithms when are generating valid models of the data in classification problems with the Gain of Entropy through Maximum Entropy Principle. The Numeric Taxonomy aims to group operational taxonomic units in clusters (OTUs or taxons or taxa, using the denominated structure analysis by means of numeric methods. These clusters that constitute families are the purpose of this series of projects and they emerge of the structural analysis, of their phenotypical characteristic, exhibiting the relationships in terms of grades of similarity of the OTUs, employing tools such as i the Euclidean distance and ii nearest neighbor techniques. Thus taxonomic evidence is gathered so as to quantify the similarity for each pair of OTUs (pair-group method obtained from the basic data matrix and in this way the significant concept of spectrum of the OTUs is introduced, being based

  2. An Introduction to Applied Biogeography

    Science.gov (United States)

    Spellerberg, Ian F.; Sawyer, John W. D.

    1999-03-01

    Biogeography is about the geographical distribution, both past and present, of plants, animals and other organisms. In this undergraduate textbook, Spellerberg and Sawyer bring a modern approach to a developing subject, writing in a lively and sometimes provocative manner. Throughout the text, the authors emphasize the applications of biogeography to conservation management, economic production, environmental assessment, sustainable use of resources, landscape planning, and public health. They discuss applications of island biogeography in conservation, the concept of wildlife corridors, the analysis of biogeographical data, and the role of humans and their cultures in biogeography. The applied approach of this textbook, along with its numerous illustrative examples and figures, make it a unique introduction to the field for many geography, biology and environmental science students.

  3. Radioisotope-applied measuring instruments

    International Nuclear Information System (INIS)

    Fuji Electric developed a new type detector for gamma thickness gauges, inner-mill housing gamma thickness gauges at hot plate mills and tube-wall thickness gauges at hot seamless tube mills. This detector attained much higher gamma counting and much lower drift than our former detectors. We plan to apply this detector to our new type thickness gauges and also renewal of now working thickness gauges at customer's site. In addition, we developed a soil mass measuring instrument for on-line measurement of cutting soil mass in a waste water tube in shield tunneling. This instrument is free from legal control and can be used in every field of civil engineering. (author)

  4. Implementing an Applied Science Program

    Science.gov (United States)

    Rickman, Doug; Presson, Joan

    2007-01-01

    The work implied in the NASA Applied Science Program requires a delicate balancing act for the those doing it. At the implementation level there are multiple tensions intrinsic to the program. For example each application of an existing product to a decision support process requires deep knowledge about the data and deep knowledge about the decision making process. It is highly probable no one person has this range of knowledge. Otherwise the decision making process would already be using the data. Therefore, a team is required. But building a team usually requires time, especially across agencies. Yet the program mandates efforts of relatively short duration. Further, those who know the data are scientists, which makes them essential to the program. But scientists are evaluated on their publication record. Anything which diverts a scientist from the research for his next publication is an anathema to him and potential death to their career. Trying to get another agency to use NASA data does not strike most scientists as material inherently suitable for publication. Also, NASA wishes to rapidly implement often substantial changes to another agency's process. For many reasons, such as budget and program constraints, speed is important. But the owner of a decision making process is tightly constrained, usually by law, regulation, organization and custom. Changes when made are slow, cautious, even hesitant, and always done according a process specific to the situation. To manage this work MSFC must balance these and other tensions. Some things we have relatively little control over, such as budget. These we try to handle by structural techniques. For example by insisting all of our people work on multiple projects simultaneously we inherently have diversification of funding for all of our people. In many cases we explicitly use some elements of tension to be productive. For example the need for the scientists to constantly publish is motivation to keep tasks short and

  5. [Basic science and applied science].

    Science.gov (United States)

    Pérez-Tamayo, R

    2001-01-01

    A lecture was presented by the author at the Democratic Opinion Forum on Health Teaching and Research, organized by Mexico's National Health Institutes Coordinating Office, at National Cardiology Institute "Ignacio Chavez", where he presented a critical review of the conventional classification of basic and applied science, as well as his personal view on health science teaching and research. According to the author, "well-conducted science" is that "generating reality-checked knowledge" and "mis-conducted science" is that "unproductive or producing 'just lies' and 'non-fundable'. To support his views, the author reviews utilitarian and pejorative definitions of science, as well as those of committed and pure science, useful and useless science, and practical and esoterical science, as synonyms of applied and basic science. He also asserts that, in Mexico, "this classification has been used in the past to justify federal funding cutbacks to basic science, allegedly because it is not targeted at solving 'national problems' or because it was not relevant to priorities set in a given six-year political administration period". Regarding health education and research, the author asserts that the current academic programs are inefficient and ineffective; his proposal to tackle these problems is to carry out a solid scientific study, conducted by a multidisciplinary team of experts, "to design the scientific researcher curricula from recruitment of intelligent young people to retirement or death". Performance assessment of researchers would not be restricted to publication of papers, since "the quality of scientific work and contribution to the development of science is not reflected by the number of published papers". The English version of this paper is available at: http://www.insp.mx/salud/index.html PMID:11547597

  6. Applied extreme-value statistics

    Energy Technology Data Exchange (ETDEWEB)

    Kinnison, R.R.

    1983-05-01

    The statistical theory of extreme values is a well established part of theoretical statistics. Unfortunately, it is seldom part of applied statistics and is infrequently a part of statistical curricula except in advanced studies programs. This has resulted in the impression that it is difficult to understand and not of practical value. In recent environmental and pollution literature, several short articles have appeared with the purpose of documenting all that is necessary for the practical application of extreme value theory to field problems (for example, Roberts, 1979). These articles are so concise that only a statistician can recognise all the subtleties and assumptions necessary for the correct use of the material presented. The intent of this text is to expand upon several recent articles, and to provide the necessary statistical background so that the non-statistician scientist can recognize and extreme value problem when it occurs in his work, be confident in handling simple extreme value problems himself, and know when the problem is statistically beyond his capabilities and requires consultation.

  7. Computer simulations applied in materials

    International Nuclear Information System (INIS)

    This workshop takes stock of the simulation methods applied to nuclear materials and discusses the conditions in which these methods can predict physical results when no experimental data are available. The main topic concerns the radiation effects in oxides and includes also the behaviour of fission products in ceramics, the diffusion and segregation phenomena and the thermodynamical properties under irradiation. This document brings together a report of the previous 2002 workshop and the transparencies of 12 presentations among the 15 given at the workshop: accommodation of uranium and plutonium in pyrochlores; radiation effects in La2Zr2O7 pyrochlores; first principle calculations of defects formation energies in the Y2(Ti,Sn,Zr)2O7 pyrochlore system; an approximate approach to predicting radiation tolerant materials; molecular dynamics study of the structural effects of displacement cascades in UO2; composition defect maps for A3+B3+O3 perovskites; NMR characterization of radiation damaged materials: using simulation to interpret the data; local structure in damaged zircon: a first principle study; simulation studies on SiC; insertion and diffusion of He in 3C-SiC; a review of helium in silica; self-trapped holes in amorphous silicon dioxide: their short-range structure revealed from electron spin resonance and optical measurements and opportunities for inferring intermediate range structure by theoretical modelling. (J.S.)

  8. Applied discrete-time queues

    CERN Document Server

    Alfa, Attahiru S

    2016-01-01

    This book introduces the theoretical fundamentals for modeling queues in discrete-time, and the basic procedures for developing queuing models in discrete-time. There is a focus on applications in modern telecommunication systems. It presents how most queueing models in discrete-time can be set up as discrete-time Markov chains. Techniques such as matrix-analytic methods (MAM) that can used to analyze the resulting Markov chains are included. This book covers single node systems, tandem system and queueing networks. It shows how queues with time-varying parameters can be analyzed, and illustrates numerical issues associated with computations for the discrete-time queueing systems. Optimal control of queues is also covered. Applied Discrete-Time Queues targets researchers, advanced-level students and analysts in the field of telecommunication networks. It is suitable as a reference book and can also be used as a secondary text book in computer engineering and computer science. Examples and exercises are includ...

  9. Computer simulations applied in materials

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This workshop takes stock of the simulation methods applied to nuclear materials and discusses the conditions in which these methods can predict physical results when no experimental data are available. The main topic concerns the radiation effects in oxides and includes also the behaviour of fission products in ceramics, the diffusion and segregation phenomena and the thermodynamical properties under irradiation. This document brings together a report of the previous 2002 workshop and the transparencies of 12 presentations among the 15 given at the workshop: accommodation of uranium and plutonium in pyrochlores; radiation effects in La{sub 2}Zr{sub 2}O{sub 7} pyrochlores; first principle calculations of defects formation energies in the Y{sub 2}(Ti,Sn,Zr){sub 2}O{sub 7} pyrochlore system; an approximate approach to predicting radiation tolerant materials; molecular dynamics study of the structural effects of displacement cascades in UO{sub 2}; composition defect maps for A{sup 3+}B{sup 3+}O{sub 3} perovskites; NMR characterization of radiation damaged materials: using simulation to interpret the data; local structure in damaged zircon: a first principle study; simulation studies on SiC; insertion and diffusion of He in 3C-SiC; a review of helium in silica; self-trapped holes in amorphous silicon dioxide: their short-range structure revealed from electron spin resonance and optical measurements and opportunities for inferring intermediate range structure by theoretical modelling. (J.S.)

  10. Applied computation and security systems

    CERN Document Server

    Saeed, Khalid; Choudhury, Sankhayan; Chaki, Nabendu

    2015-01-01

    This book contains the extended version of the works that have been presented and discussed in the First International Doctoral Symposium on Applied Computation and Security Systems (ACSS 2014) held during April 18-20, 2014 in Kolkata, India. The symposium has been jointly organized by the AGH University of Science & Technology, Cracow, Poland and University of Calcutta, India. The Volume I of this double-volume book contains fourteen high quality book chapters in three different parts. Part 1 is on Pattern Recognition and it presents four chapters. Part 2 is on Imaging and Healthcare Applications contains four more book chapters. The Part 3 of this volume is on Wireless Sensor Networking and it includes as many as six chapters. Volume II of the book has three Parts presenting a total of eleven chapters in it. Part 4 consists of five excellent chapters on Software Engineering ranging from cloud service design to transactional memory. Part 5 in Volume II is on Cryptography with two book...

  11. Sensitivity of positive ion mode electrospray ionization mass spectrometry (ESI MS) in the analysis of purine bases in ESI MS and on-line electrochemistry ESI MS (EC/ESI MS)

    Energy Technology Data Exchange (ETDEWEB)

    Mautjana, Nare Alpheus; Looi, Donq Wen; Eyler, John R. [Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL, 32611-7200 (United States); Brajter-Toth, Anna, E-mail: atoth@chem.ufl.ed [Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL, 32611-7200 (United States)

    2009-12-15

    A cone-shaped MS inlet and on-line electrochemistry (EC) were used to enhance the ionization efficiency in electrospray ionization mass spectrometry (ESI MS) of purine bases. A pathway of positive ion mode ESI may involve oxidation of purine bases, guanine, adenine, xanthine and hypoxanthine, by 1e{sup -}, 1H{sup +} processes. The electrospray process generates dimers of purine bases that are detected in ESI MS as protonated ions, except for xanthine, for which a protonated radical dimer is detected. Thus electrochemical oxidation of purine bases during ESI may generate reactive radicals that can subsequently dimerize. Dimer formation is facilitated in ESI MS when the carrier solution pH is high. The positive ion mode ESI MS ionization is consistent with the reactivity of the bases toward oxidation. Furthermore, the formation of the protonated ions, and Na{sup +} and K{sup +} adducts of the bases, expected in positive ion ESI MS, are observed. In addition, unusual H-bonding of purine bases guanine and xanthine is confirmed by ESI MS. Application of low EC voltage to the on-line EC cell in EC/ESI MS improves the sensitivity and correlates with the decrease of the intensity of the dimers, possibly as a result of their further oxidation.

  12. THE OUTLOOK FOR APPLIED ENTOMOLOGY.

    Science.gov (United States)

    1891-01-16

    I have thus touched, gentlemen, upon a few of the many subjects that crowd upon the mind for consideration on an occasion like this, - a few gleanings from a field which is passing rich in promise and possibility. It is a field that some of us have cultivated for many years, and yet have only scratched the surface ; and, if I have ventured to suggest or admonish, it is with the feeling that my own labors in this field are ere long about to end, and that I may not have another occasion. At no time in the history of the world has there, I trow, been gathered together such a body of devoted and capable workers in applied entomology. It marks an era in our calling, and, looking back at the progress of the past fifteen years, we may well ponder the possibilities of the next fifteen. They will be fruitful of grand results in proportion as we persistently and combinedly pursue the yet unsolved problems, and are not tempted to the immediate presentation of separate facts, which are so innumerable and so easily observed that their very wealth becomes an element of weakness. Epoch-making discoveries result only from this power of following up unswervingly any given problem or any fixed ideal. The kerosene emulsion ; the cyclone nozzle ; the history of Phylloxera vastatrix, of Phorodon humuli, of Vedalia cardinalis,- are illustrations in point: and, while we may not expect frequent results as striking or of as wide application as these, there is no end of important problems yet to be solved, and from the solution of which we may look for similar beneficial results. Applied entomology is often considered a sordid pursuit ; but it only becomes so when the object is sordid. When pursued with unselfish enthusiasm born of the love of investigation and the delight in benefiting our fellow-men, it is inspiring ; and there are few pursuits more deservedly so, considering the vast losses to our farmers from insect injury and the pressing need that the distressed husbandman has for

  13. Counterforce applied to prevent spalling

    International Nuclear Information System (INIS)

    The field experiment within CAPS (Counterforce Applied to Prevent Spalling) was initiated to determine if the application of dry bentonite pellets is sufficient to suppress thermally-induced spalling in KBS-3 deposition holes. The experience gained from Aespoe Pillar Stability Experiment, conducted between 2002 and 2006, indicated that spalling could be controlled by the application of a small confining pressure in the deposition holes. The CAPS field experiment that included four pairs of boreholes with a diameter of approximately 0.5 m, was carried out as a series of demonstration experiments in the TASQ-tunnel. The first and second heating tests were performed in open holes, without any confining pressure on the borehole wall and the third and fourth heating tests with a confining pressure created by expanded clay pellets (LECA). The first heating test was initiated at the end of August 2008 and the final test was finished at the end of May 2009. The trials suggest that the small confining pressure offered by the LECA pellets was adequate to control spalling and prevent the formation of a highly conductive zone of fractured rock in the 500-mm-diameter holes. It is recommended that a full-scale test be carried out to assess if the findings are applicable to 1,750-mm-diameter deposition holes. Should the full scale tests support the findings from these initial trials, filling the gap between the bentonite blocks and rock wall with dry bentonite pellets will provide a viable engineered solution for controlling the effects of thermally induced spalling in the KBS-3 deposition holes

  14. Counterforce applied to prevent spalling

    Energy Technology Data Exchange (ETDEWEB)

    Glamheden, Rune; Bergkvist, Lars (Golder Associates AB (Sweden)); Faelth, Billy (Clay Technology AB, Lund (Sweden)); Jacobsson, Lars (SP Technical Research Institute of Sweden, Boraas (Sweden)); Harrstroem, Johan (Geosigma AB, Uppsala (Sweden)); Berglund, Johan (Vattenfall Power Consultant AB, Stockholm (Sweden))

    2010-04-15

    The field experiment within CAPS (Counterforce Applied to Prevent Spalling) was initiated to determine if the application of dry bentonite pellets is sufficient to suppress thermally-induced spalling in KBS-3 deposition holes. The experience gained from Aespoe Pillar Stability Experiment, conducted between 2002 and 2006, indicated that spalling could be controlled by the application of a small confining pressure in the deposition holes. The CAPS field experiment that included four pairs of boreholes with a diameter of approximately 0.5 m, was carried out as a series of demonstration experiments in the TASQ-tunnel. The first and second heating tests were performed in open holes, without any confining pressure on the borehole wall and the third and fourth heating tests with a confining pressure created by expanded clay pellets (LECA). The first heating test was initiated at the end of August 2008 and the final test was finished at the end of May 2009. The trials suggest that the small confining pressure offered by the LECA pellets was adequate to control spalling and prevent the formation of a highly conductive zone of fractured rock in the 500-mm-diameter holes. It is recommended that a full-scale test be carried out to assess if the findings are applicable to 1,750-mm-diameter deposition holes. Should the full scale tests support the findings from these initial trials, filling the gap between the bentonite blocks and rock wall with dry bentonite pellets will provide a viable engineered solution for controlling the effects of thermally induced spalling in the KBS-3 deposition holes

  15. Electrochemistry and application of a novel monosubstituted squarate electron-transfer mediator in a glucose oxidase-doped poly(phenol) sensor

    OpenAIRE

    Iwuoha, Emmanuel I.; Williams-Dottin, Avril R.; Hall, Lincoln A.; Morrin, Aoife; Mathebe, Gretta N.; Smyth, Malcolm R.; Killard, Anthony J.

    2004-01-01

    Electrosynthetic poly(phenol) nanofilms were deposited in situ on platinum electrodes in the presence and absence of glucose oxidase. The synthesis charges and currents of the nonconducting polymer films were recorded at various applied potentials for films grown from 25–100 mM phenol concentrations. Film parameters such as the standard rate constant for film deposition, film thickness, and surface concentration of the poly(phenol) films were evaluated from the cyclic and step ...

  16. Distinguishing between applied research and practice

    OpenAIRE

    James M. Johnston

    1996-01-01

    Behavior-analytic research is often viewed along a basic—applied continuum of research goals and methods. The applied portion of this continuum has evolved in ways that combine applied research and service delivery. Although these two facets of applied behavior analysis should be closely related, more clearly distinguishing between them, particularly in how we conceptualize and conduct applied research, may enhance the continuing development of each. This differentiation may improve the recru...

  17. Direct electrochemistry of glucose oxidase on hydroxyapatite/Nafion composite film modified electrode and its application for glucose biosensing%葡萄糖氧化酶在羟基磷灰石/Nafion复合膜修饰电极上的直接电化学及其对葡萄糖的生物传感

    Institute of Scientific and Technical Information of China (English)

    马荣娜; 王斌; 刘燕; 李静; 赵倩; 王国涛; 贾文丽; 王怀生

    2009-01-01

    将葡萄糖氧化酶固定于羟基磷灰石(HAp)-Nafion复合膜,构建了高灵敏、高选择性的葡萄糖传感器.羟基磷灰石和Nafion良好的协同作用,可以有效地提高传感器的稳定性与灵敏度.实验结果表明:固定在复合膜修饰电极上的葡萄糖氧化酶呈现出一对较好的近乎可逆的氧化还原峰,并且对葡萄糖的氧化有良好的催化作用,同时消耗溶解氧,从而导致溶解氧还原峰的降低.在-0.8 V处,随葡萄糖浓度的增加,葡萄糖氧化酶催化葡萄糖氧化时消耗溶解氧的量增加,溶解氧还原电流逐渐降低,因此该修饰电极可以作为葡萄糖传感器实现对葡萄糖的高灵敏检测.在0.12~2.16 mmol·L~(-1)浓度范围内,溶解氧还原电流的降低与葡萄糖的浓度成正比,据此可以测定出溶液中葡萄糖的浓度,该传感器的检出限和灵敏度分别为0.02 mmol·L~(-1)(S/N=3)和6.75 mA·L·mol~(-1).因此,HAp-Nafion复合膜为酶的固定和直接电化学研究提供了一个新的有效平台,在构建新型无试剂葡萄糖传感器方面具有较大的应用前景.%A novel glucose biosensor was constructed by immobilizing the glucose oxidase (GOD) on a hydroxyapa-tite (Hap)/Nafion composite film modified glassy carbon electrode (GCE) and applied to the highly selective and sensitive determination of glucose.With the cooperation of Hap and Nafion,the composite film played an important role in enhancing the stability and sensitivity of the biosensor.The results demonstrated that the GOD adsorbed onto the Hap/Nafion composite film exhibits a pair of well-defined nearly reversible redox peaks and fine catalysis to the oxidation of glucose companied with the consumption of dissolved oxygen.Based on the decrease of the reduction current of dissolved oxygen at the applied potential of -0.80 V (vs.SCE) upon the addition of glucose,the concentration of glucose could be detected sensitively and selectively.The decreased reduction current

  18. Applied Psycholinguistics--Amphibian or Phantom?

    Science.gov (United States)

    Titone, Renzo

    1975-01-01

    A tentative classification of internal departments of psycholinguistics is suggested and a list of applied fields is presented. Applied psycholinguistics is not seen here to have a right to scientific independence. (SCC)

  19. Applied Parallel Computing Industrial Computation and Optimization

    DEFF Research Database (Denmark)

    Madsen, Kaj; NA NA NA Olesen, Dorte

    Proceedings and the Third International Workshop on Applied Parallel Computing in Industrial Problems and Optimization (PARA96)......Proceedings and the Third International Workshop on Applied Parallel Computing in Industrial Problems and Optimization (PARA96)...

  20. Applied Materials taas investorite huviorbiidis / Erlend Zirk

    Index Scriptorium Estoniae

    Zirk, Erlend

    2006-01-01

    Ilmunud ka: Delovõje Vedomosti 29. nov. lk. 33. Protsessorite tootmisseadmete tootja Applied Materials on pärast 2000. aasta börsikrahhi taas investorite huviorbiiti jõudmas. Diagramm: Applied Materialsi aktsia

  1. Research on the treatment of fracturing flow-back fluid by coagulation-magnet separation-electrochemistry combined technology%混凝-磁分离-电化学技术处理压裂返排液研究

    Institute of Scientific and Technical Information of China (English)

    张太亮; 欧阳铖; 郭威; 张芳捷; 范开鑫

    2016-01-01

    The components,characteristics and treatment actuality of fracturing flow-back fluid from shale gas explo-ration are analyzed. It is put forward that the gel-breaking coagulation-magnetic separation-electrochemistry catalysis oxidation technology is used for treating fracturing flow-back fluid. The optimized technology of every treatment unit is obtained through researches,among which gel-breaker K2FeO4 is used in the gel-breaking coagulation process. The conditions needed are as follows:the dosage of K2FeO4 is 2 500 mg/L,PAFC dosage 2 000 mg/L, reacting pH 11.0 and reaction time 40 min. Nano-magnet powder 4 000 mg/L and polymer flocculant HPAM 20 mg/L are needed for the magnetic separation process. Ti/TiO2 plate is used as anode,while stainless steel plate as cathode, oxidation voltage 10.0 V,current density1.6×10-2 A/cm2,reaction pH of the system 11.0 and reaction time 30 min are needed for the electrochemistry catalysis oxidation process. The research results show that after the above technology and optimized processes have been used for the treatment of fracturing flow-back fluid,all of the main factors,such as COD,SS,oil content,chroma,pH,etc. meet the requirements specified in the first class of the Integrated Wastewater Discharge Standard(GB 8978—2002).%对页岩气开采中压裂返排液的组成、特性及处理现状进行分析,提出采用破胶混凝—磁分离—电化学催化氧化技术处理压裂返排液。研究得到各处理单元优化工艺,其中破胶混凝工艺采用高铁酸钾破胶剂、投加量2500 mg/L,混凝剂聚合氯化铝铁投加量为2000 mg/L,反应pH为11.0,反应时间40 min;磁分离工艺采用纳米磁铁粉,投加量4000 mg/L,高分子絮凝剂阴离子聚丙烯酰胺投加量为20 mg/L;电化学催化氧化工艺采用Ti/TiO2作阳极,不锈钢作阴极,氧化电压10.0 V,电流密度1.6×10-2 A/cm2,体系pH为11.0,反应时间30 min。研究结果表明,采用上述技术及优

  2. The technical drift of applied behavior analysis

    OpenAIRE

    Hayes, Steven C.; Rincover, Arnold; Solnick, Jay V.

    1980-01-01

    Four dimensions (applied, analytic, general, conceptual) were selected from Baer, Wolf, and Risley's (1968) seminal article on the nature of applied behavior analysis and were monitored throughout the first 10 volumes of the Journal of Applied Behavior Analysis. Each of the experimental articles in Volumes 1 through 6 and the first half of Volumes 7 through 10 was rated on each of these dimensions. The trends showed that applied behavior analysis is becoming a more purely technical effort, wi...

  3. 无定形介孔磷酸锆固定葡萄糖氧化酶的直接电化学%Direct electrochemistry of immobilized glucose oxidase on amorphous mesoporous zirconium phosphate

    Institute of Scientific and Technical Information of China (English)

    于志辉; 黄鹏飞; 汪夏燕

    2016-01-01

    Glucose oxidase (GOD)/zirconium phosphate(ZrP)/glassy carbon(GC) electrode was prepared by adsorbing GOD on the amorphous mesoporous zirconium phosphate. The electrocatalytic properties of GOD/ZrP/GC electrode were characterized by cyclic voltammetric method at the medium of phosphate buffer (0.1 mol·L?1). The results showed that there were quicker electron transfer rate and larger surface coverage when GOD was supported on zirconium phosphate. At the same time, the electrochemical device with this electrode showed faster current response and higher sensitivity in detection of glucose, indicating that zirconium phosphate could be more suitable support for immobilization of GOD and achieve better performance of direct electrochemistry.%利用无定形介孔磷酸锆(ZrP)为载体,通过吸附法固定葡萄糖氧化酶(GOD),修饰玻碳(GC)电极得到GOD/ZrP/GC电极.在0.1 mol·L?1磷酸盐缓冲溶液中,利用循环伏安法研究了GOD/ZrP/GC电极的直接电化学行为和对葡萄糖的催化性能.结果表明,无定形磷酸锆ZrP为载体修饰的电极GOD/ZrP/GC其电化学反应电子转移速率快、表观覆盖量大;对葡萄糖的检测表现出较快的电流响应和较高的灵敏度,说明无定形磷酸锆更有利于GOD的固定和酶电极的直接电化学.

  4. Critical and Alternative Directions in Applied Linguistics

    Science.gov (United States)

    Pennycook, Alastair

    2010-01-01

    Critical directions in applied linguistics can be understood in various ways. The term "critical" as it has been used in "critical applied linguistics," "critical discourse analysis," "critical literacy" and so forth, is now embedded as part of applied linguistic work, adding an overt focus on questions of power and inequality to discourse…

  5. Western Perspectives in Applied Linguistics in Africa

    Science.gov (United States)

    Makoni, Sinfree; Meinhof, Ulrike H.

    2004-01-01

    The aim of this article is to analyze the nature of the historical and contemporary social contexts within which applied linguistics in Africa emerged, and is currently practiced. The article examines the challenges "local" applied Linguistics in Africa is confronted with as it tries to amplify applied linguistic programs emanating from…

  6. Towards quantitative measures in applied ontology

    CERN Document Server

    Hoehndorf, Robert; Gkoutos, Georgios V

    2012-01-01

    Applied ontology is a relatively new field which aims to apply theories and methods from diverse disciplines such as philosophy, cognitive science, linguistics and formal logics to perform or improve domain-specific tasks. To support the development of effective research methodologies for applied ontology, we critically discuss the question how its research results should be evaluated. We propose that results in applied ontology must be evaluated within their domain of application, based on some ontology-based task within the domain, and discuss quantitative measures which would facilitate the objective evaluation and comparison of research results in applied ontology.

  7. A Highly Efficient Mixed-culture Biofilm as Anodic Catalyst and Insights into Its Enhancement through Electrochemistry by Comparison with G. sulfurreducens

    International Nuclear Information System (INIS)

    Highlights: • A mixed-culture biofilm with 68.6% higher current than Geobacter sulfurreducens was firstly reported, while G. sulfurreducens biofilm showed five-time higher apparent affinity than the mixed-culture. • The mixed-culture biofilm showed surface-controlled process, while diffusion-controlled process was obtained for G. sulfurreducens as at certain accelerating scan rates. • When the used medium was replaced with the fresh, decrease percentage of currents for both kinds of biofilms is similar (50%). • A suitable community will be an alternative for improving MFC performance. - Abstract: In this paper an efficient mixed-culture microbial biofilm with increased current density by 68.6% (1020.9 ± 47 μA cm−2) than that on typical culture of Geobacter sulfurreducens biofilm was firstly reported. The insights into the enhanced electricity-producing ability was investigated through evaluating the dependence of limiting current density on electroactive biomass coverage, replacing used growth medium, applying stirring and electron transfer kinetics. It was shown that the enhanced electricity generation ability of the mixed-culture biofilm is from population superiority of active molecules or electron shuttles from the biofilm. This work suggested that the optimized synergistic effect between interspecies in community could significantly improve electricity-producing performance than single strain. This study highlighted the potential synergistic role in special community on electricity generation capability

  8. Electrochemistry of bilirubin oxidase and its use in preparation of a low cost enzymatic biofuel cell based on a renewable composite binder chitosan

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: Spherical carbon nanoparticles KetjenBlack (KB) with a high sorption capacity together with conductivity increasing single walled carbon nanotubes (CNTs) were “glued” together by chitosan for the preparation of a composite. A biocathode with bilirubin oxidase (BOD) adsorbed within the composite was characterised and its composition optimised. A renewable biopolymer chitosan present in the composite offered (1) pre-concentration of BOD within the matrix via electrostatic interactions, (2) favourable orientation of BOD for a direct electron transfer (DET) between BOD and the composite, (3) electrochemical visibility of 3 redox sites present in BOD, (4) low charge transfer resistance, (5) high proton conductivity and (6) low overpotential for oxygen reduction. Electrochemical investigation of BOD revealed interesting internal redox communication within the enzyme with some novel insights provided. At least one of tyrosines present in BOD seems to be involved in electron transfer route, as well. The composite used for the biocathode was directly applied for the preparation of a bioanode with fructose dehydrogenase immobilised, working in a DET mode of operation. Finally, integration of the biocathode and the bioanode into a biofuel cell operated in a reagentless and membraneless mode offered a power density of 50 μW cm−2 at 300 mV.

  9. In-situ SERS spectroscopic electrochemistry of N-(4,6-dimethoxypyrimidin-2-y1-N′-nicotinoylthioureon the silver electrode

    Directory of Open Access Journals (Sweden)

    JIN Qiao

    2014-06-01

    Full Text Available Surface Enhanced Raman Scattering (SERS is a surface analysis technique with high sensitivity,which is widely applied in the study of the behavior of interface adsorption,molecular interface orientation,and the change of the adsorption.Self-assembled monolayers (SAMs technique is regarded as a reasonable method to controllably construct an orderly uniform layers that can provide a simple interfacial model for surface analysis.N-(4,6-di-methoxypyrimidin-2-y1-N′-nicotinoylthioure(DMPNTis a newly synthesized functional molecule,which will hopefully become the special herbicide for the lawns.However,no spectroscopic characteristic of this molecule has been reported.In this work,the adsorption and desorption behavior of DMPNT monolayer on an Ag electrode was observed by in-situ SERS.The experimental results showed that DMPNT was self-assembled on Ag surface through thiol group with its pyridine ring close to the surface.The adsorption behavior of DMPNT changed along with the negative-shifting of the potential:the pyridine ring turned over,and the amido and the methoxy group became closer to the surface.When the potential negatively shifted to -1.2 V vs.SCE,the DMPNT completely detached from the surface.

  10. Direct Electrochemistry of Hemoglobin Immobilized on a Functionalized Multi-Walled Carbon Nanotubes and Gold Nanoparticles Nanocomplex-Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Nader Sheibani

    2013-07-01

    Full Text Available Direct electron transfer of hemoglobin (Hb was realized by immobilizing Hb on a carboxyl functionalized multi-walled carbon nanotubes (FMWCNTs and gold nanoparticles (AuNPs nanocomplex-modified glassy carbon electrode. The ultraviolet-visible absorption spectrometry (UV-Vis, transmission electron microscopy (TEM and Fourier transform infrared (FTIR methods were utilized for additional characterization of the AuNPs and FMWCNTs. The cyclic voltammogram of the modified electrode has a pair of well-defined quasi-reversible redox peaks with a formal potential of −0.270 ± 0.002 V (vs. Ag/AgCl at a scan rate of 0.05 V/s. The heterogeneous electron transfer constant (ks was evaluated to be 4.0 ± 0.2 s−1. The average surface concentration of electro-active Hb on the surface of the modified glassy carbon electrode was calculated to be 6.8 ± 0.3 × 10−10 mol cm−2. The cathodic peak current of the modified electrode increased linearly with increasing concentration of hydrogen peroxide (from 0.05 nM to 1 nM with a detection limit of 0.05 ± 0.01 nM. The apparent Michaelis-Menten constant (Kmapp was calculated to be 0.85 ± 0.1 nM. Thus, the modified electrode could be applied as a third generation biosensor with high sensitivity, long-term stability and low detection limit.

  11. Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized in a DNA/Chitosan-Fe3O4 Magnetic Nanoparticle Bio-Complex Film

    Directory of Open Access Journals (Sweden)

    Tingting Gu

    2014-02-01

    Full Text Available A DNA/chitosan-Fe3O4 magnetic nanoparticle bio-complex film was constructed for the immobilization of horseradish peroxidase (HRP on a glassy carbon electrode. HRP was simply mixed with DNA, chitosan and Fe3O4 nanoparticles, and then applied to the electrode surface to form an enzyme-incorporated polyion complex film. Scanning electron microscopy (SEM was used to study the surface features of DNA/chitosan/Fe3O4/HRP layer. The results of electrochemical impedance spectroscopy (EIS show that Fe3O4 and enzyme were successfully immobilized on the electrode surface by the DNA/chitosan bio-polyion complex membrane. Direct electron transfer (DET and bioelectrocatalysis of HRP in the DNA/chitosan/Fe3O4 film were investigated by cyclic voltammetry (CV and constant potential amperometry. The HRP-immobilized electrode was found to undergo DET and exhibited a fast electron transfer rate constant of 3.7 s−1. The CV results showed that the modified electrode gave rise to well-defined peaks in phosphate buffer, corresponding to the electrochemical redox reaction between HRP(Fe(III and HRP(Fe(II. The obtained electrode also displayed an electrocatalytic reduction behavior towards H2O2. The resulting DNA/chitosan/Fe3O4/HRP/glassy carbon electrode (GCE shows a high sensitivity (20.8 A·cm−2·M−1 toward H2O2. A linear response to H2O2 measurement was obtained over the range from 2 µM to 100 µM (R2 = 0.99 and an amperometric detection limit of 1 µM (S/N = 3. The apparent Michaelis-Menten constant of HRP immobilized on the electrode was 0.28 mM. Furthermore, the electrode exhibits both good operational stability and storage stability.

  12. Electrochemistry and Near-infrared Electrochromism of Electropolymerized Polydithiophenes with β, β′-Positions Bridged by Carbonyl or Dicarbonyl Substitute

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Polydithiophenes bridged by carbonyl or dicarbonyl substitute as two electron-acceptors were electrosynthesized from Lewis acidic electrolyte;. • The growth of the two polymers were monitored by in situ spectroelectrochemical and microgravimetric methods;. • The enhanced NIR electrochromics of the two polymers were found;. • The two polymers are of comparable intermolecular spacings but different electrochemical and thermal stability. - Abstract: The β, β′-positions carbonyl or dicarbonyl bridged dithiophenes were prepared and electrochemically polymerized into corresponding polymers, polycyclopenta[2,1-b;3,4-b′]dithiophen-4-one (PCDK) or polybenzo[1,2-b:6,5-b′]dithiophene-4,5-dione (PCD2K), in boron trifluoride diethyl etherate based electrolyte. Potentiostatic and potentiodynamic methods confirmed that the PCDK and PCD2K films can be successfully electrodeposited in high quality with comparable intermolecular spacings at around 3.1 Å-3.2 Å. The mass changes and ion transport of the two polymers during redox processes were studied by electrochemical quartz crystal microbalance and in situ spectroelectrochemical methods, to investigate the formation of the two polymers. In situ UV-visible spectroscopy evidenced the PCDK and PCD2K evolved into polarons in the near infrared region under applied potentials. Electrochromic behaviors showed that the PCDK film appeared reddish brown in neutral state and cyan or green in oxidized state while the PCD2K showed green to dark green from neutral to oxidized states. Potential switching between oxidized and neutral states of the two films revealed that maxima transmittance changes were 38.23% and 36.64% for the PCDK and PCD2K. Thermal degradation of the two polymers showed their robust stability that allows for the application in a wide temperature scale

  13. The basic importance of applied behavior analysis

    OpenAIRE

    Epling, W. Frank; Pierce, W. David

    1986-01-01

    We argue that applied behavior analysis is relevant to basic research. Modification studies, and a broad range of investigations that focus on the precipitating and maintaining conditions of socially significant human behavior, have basic importance. Applied behavior analysis may aid basic researchers in the design of externally valid experiments and thereby enhance the theoretical significance of basic research for understanding human behavior. Applied research with humans, directed at cultu...

  14. Applied behavior analysis and statistical process control?

    OpenAIRE

    Hopkins, B. L.

    1995-01-01

    This paper examines Pfadt and Wheeler's (1995) suggestions that the methods of statistical process control (SPC) be incorporated into applied behavior analysis. The research strategies of SPC are examined and compared to those of applied behavior analysis. I argue that the statistical methods that are a part of SPC would likely reduce applied behavior analysts' intimate contacts with the problems with which they deal and would, therefore, likely yield poor treatment and research decisions. Ex...

  15. Applied Implications of Reinforcement History Effects

    OpenAIRE

    Pipkin, Claire St. Peter; Vollmer, Timothy R

    2009-01-01

    Although the influence of reinforcement history is a theoretical focus of behavior analysis, the specific behavioral effects of reinforcement history have received relatively little attention in applied research and practice. We examined the potential effects of reinforcement history by reviewing nonhuman, human operant, and applied research and interpreted the findings in relation to possible applied significance. The focus is on reinforcement history effects in the context of reinforcement ...

  16. Applied linguistics - a science of culture?

    OpenAIRE

    Benke, Gertraud

    2003-01-01

    In this article, the status of applied linguistics as discipline is questioned and problems of establishing it - and other newly formed scientific enterprises like cultural science - as disciplines are discussed. This discussion is contextualized using the author's own experience as applied linguist working in (the institutional structure of) Austria. Secondly, applied linguistics is presented as complementing cultural science, with both exploring at times the same phenomena albeit under diff...

  17. Perspectives in biotechnology and applied microbiology

    Energy Technology Data Exchange (ETDEWEB)

    Alani, D.I.

    1986-01-01

    Upon an invitation from Arab Burea of Education for the Gulf States 'ABEGS', an International Converence on Biotechnology and Applied Microbiology was held in Riyadh, Saudi Arabia. The conference was sponsored by ABEGS and organised through cooperation with Saudi Biological Society (SEBS). The main topics were grouped into sections representing seven themes of Biotechnology and Applied Microbiology-production of microbial proteins; utilization of microorganisms for the production of chemicals; microbial treatment and utilization of waste; continuous culture; application of biotechnology in plant science; applied microbiology and environment and applied microbiology and biotechnology; international cooperation between developed and developing countries.

  18. Applied Indigenous Studies at Northern Arizona University.

    Science.gov (United States)

    Trosper, Ronald L.

    2001-01-01

    The Applied Indigenous Studies program at Northern Arizona University aims to prepare American Indian students to assume tribal leadership roles. Its location in the College of Ecosystem Science and Management emphasizes its land-oriented and applied focus. The program's development, core courses, and academic requirements for bachelors degrees…

  19. Applied Behavior Analysis and Statistical Process Control?

    Science.gov (United States)

    Hopkins, B. L.

    1995-01-01

    Incorporating statistical process control (SPC) methods into applied behavior analysis is discussed. It is claimed that SPC methods would likely reduce applied behavior analysts' intimate contacts with problems and would likely yield poor treatment and research decisions. Cases and data presented by Pfadt and Wheeler (1995) are cited as examples.…

  20. Applying Psychological Theories to Educational Practice

    Science.gov (United States)

    Sternberg, Robert

    2008-01-01

    Two approaches to the application of psychological theories to education might be referred to as domain-general and domain-specific. The domain-general approach seeks a general theory of cognitive and other skills that apply across subject-matter areas. The domain-specific approach seeks to apply specific theories within given domains, such as…

  1. Complexity of Stakeholder Interaction in Applied Research

    OpenAIRE

    Caroline Pade-Khene; Rebecca Luton; Tarina Jordaan; Sandra Hildbrand; Cecile Gerwel Proches; Andile Sitshaluza; James Dominy; Wonga Ntshinga; Nosipho Moloto

    2013-01-01

    Applied research in complex integrated settings should be recognized as an endeavor that requires transdisciplinary and multisectoral stakeholder interactions. The problems faced in society are quite complex, requiring participation and knowledge from diverse aspects of society, including different disciplines (academia), communities, civil society, and government. Successful applied research relies on nurturing these key stakeholder relationships and interactions. This paper explores the key...

  2. Child Participant Roles in Applied Linguistics Research

    Science.gov (United States)

    Pinter, Annamaria

    2014-01-01

    Children's status as research participants in applied linguistics has been largely overlooked even though unique methodological and ethical concerns arise in projects where children, rather than adults, are involved. This article examines the role of children as research participants in applied linguistics and discusses the limitations of…

  3. 32 CFR 37.1220 - Applied research.

    Science.gov (United States)

    2010-07-01

    ... REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Definitions of Terms Used in This Part § 37.1220 Applied research. Efforts that attempt to determine and exploit the potential of scientific discoveries or improvements in... 32 National Defense 1 2010-07-01 2010-07-01 false Applied research. 37.1220 Section...

  4. ISAE- The International Society for Applied Ethology

    Science.gov (United States)

    The International Society for Applied Ethology (ISAE) was created in 1966 as the Society for Veterinary Ethology, with a primary membership of U.K.-based veterinarians. It quickly expanded to encompass researchers and clinicians working in all areas of applied animal behavior and all over the world....

  5. Recent Developments in Applied Probability and Statistics

    CERN Document Server

    Devroye, Luc; Kohler, Michael; Korn, Ralf

    2010-01-01

    This book presents surveys on recent developments in applied probability and statistics. The contributions include topics such as nonparametric regression and density estimation, option pricing, probabilistic methods for multivariate interpolation, robust graphical modelling and stochastic differential equations. Due to its broad coverage of different topics the book offers an excellent overview of recent developments in applied probability and statistics.

  6. Applied Linguistics: The Challenge of Theory

    Science.gov (United States)

    McNamara, Tim

    2015-01-01

    Language has featured prominently in contemporary social theory, but the relevance of this fact to the concerns of Applied Linguistics, with its necessary orientation to practical issues of language in context, represents an ongoing challenge. This article supports the need for a greater engagement with theory in Applied Linguistics. It considers…

  7. Applied Linguistics in Its Disciplinary Context

    Science.gov (United States)

    Liddicoat, Anthony J.

    2010-01-01

    Australia's current attempt to develop a process to evaluate the quality of research (Excellence in Research for Australia--ERA) places a central emphasis on the disciplinary organisation of academic work. This disciplinary focus poses particular problems for Applied Linguistics in Australia. This paper will examine Applied Linguistics in relation…

  8. Autobiographic Narratives as Data in Applied Linguistics

    Science.gov (United States)

    Pavlenko, Aneta

    2007-01-01

    In the past decade, language memoirs, linguistic autobiographies, and learners' journals and diaries have become a popular means of data collection in applied linguistics. It is not always clear however how one should go about analyzing these data. The aim of this paper is to offer a critical review of analytical frameworks applied to second…

  9. Applied Implications of Reinforcement History Effects

    Science.gov (United States)

    Pipkin, Claire St. Peter; Vollmer, Timothy R.

    2009-01-01

    Although the influence of reinforcement history is a theoretical focus of behavior analysis, the specific behavioral effects of reinforcement history have received relatively little attention in applied research and practice. We examined the potential effects of reinforcement history by reviewing nonhuman, human operant, and applied research and…

  10. Active system monitoring applied on wind turbines

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad; Parbo, Henrik;

    2009-01-01

    A concept for active system monitoring (ASM) applied on wind turbines is presented in this paper. The concept is based on an injection of a small periodic auxiliary signal in the system. An investigation of the signature from the auxiliary input in residual (error) signals can then be applied for...

  11. Electrochemistry study of the influence of local hydrogen generation in carbon steel bio-corrosion mechanisms in presence of iron reducing bacteria (Shewanella oneidensis)

    International Nuclear Information System (INIS)

    electrochemical techniques were applied in order to locally generate hydrogen and to observe the influence of the increase of the availability of electron's donors. A polarized platinum tip, of 100 μm of diameter, was placed 50 μm distant from the carbon steel electrode surface. A specifically electrochemical cell was developed for this study aiming to perform local electrochemical measurements in anaerobic conditions. A biological medium (called as M1) was used as a reaction solution where only corrosion products were used as electron donor (hydrogen) and accepters (iron III oxides). The carbon steel electrode was polarized at open circuit potential (OCP) and the current variation over time was monitored. A different corrosion kinetic was observed in presence of bacteria when the hydrogen was locally generated by the tip, suggesting a reaction's acceleration. The study of this phenomenon is now under progress. (authors)

  12. Direct Electrochemistry of Hemoglobin on TiO2 Cavities Array%血红蛋白在二氧化钛球腔阵列上的直接电化学研究

    Institute of Scientific and Technical Information of China (English)

    周宇; 周丽娟; 孙磊; 尹凡

    2011-01-01

    采用Langmuir—Blodgett术和溶胶-凝胶(sol—gel)法在氧化铟锡(ITO)表面制备了TiO2球腔阵列.研究了TiO2球腔阵列的电化学性质,结果表明:所制备的TiO2球腔阵列具有微电极阵列特性.将血红蛋白(Hb)直接吸附在TiO2球腔阵列内部,制备过氧化氢(H2O2)生物传感器.修饰电极对过氧化氢(H2O2)的电流响应快速稳定、重现性和选择性较好,在9.00×10^-7~4.44×10^-4mol/L范围内H2O2浓度与响应电流呈现良好的线性关系,其检出限为3.12×10^-7mol/L,米氏常数为0.138mmol/L.%The TiO2 cavities array was fabricated on indium-tin oxide electrode surface by using Lang-muir-Blodgett technique and sol-gel technique. The electrochemistry property of TiO2 cavities array was investigated. The result showed that TiO2 cavities array had the property of microelectrode arrays. An amperometric biosensor for detection of H202 was prepared by adsorbing hemoglobin(Hb) in TiO2 cavities directly. In pH 7.0 phosphate buffer, the CV curve of Hb/TiO2 cavities array electrode showed a pair of reversible redox peaks, the catholic and anodic peak appeared at 0.042 and 0.127V, its direct electron transfer rate was 2.95s^-1. The amperometric response of the biosensor possessed properties of speediness, good stability, reproducibility, and selectivity. Under the optimal conditions, the calibration curve was linear in the range of 9.00×10^-7-4.44×10^-4 mol/L for H2O2 concentration with a detection limit of 3.12×10^-7 mol/L and the apparent Michaelis-Menten constant for HRP modified electrode was 0.138 mmol/L.

  13. Direct Electrochemistry of Glucose Oxidase on A Nano Complex Modified Glassy Carbon Electrode%葡萄糖氧化酶在修饰玻碳电极上的直接电化学

    Institute of Scientific and Technical Information of China (English)

    耿方勇; 李迪; 张钰帅; 杨晓璐; 肖宝林; 洪军

    2016-01-01

    Direct electrochemistry of glucose oxidase was realized when it was immobilized on a nano-complex modified glassy carbon electrode, and the nano-complex was composed of graphene and multi-walled carbon nanotubes. The outermost layer covered with chitosan. Using cyclic voltammetry ( CV ) to measure electrochemical and electro-catalyzed reaction of glucose oxidase that modified electrode, the electron transfer rate constant (ks) was evaluated to be 0. 87 s-1, and electroactive surface density was 1. 54í10-10 mol/cm-2. The apparent Michaelis-Menten constant (Kappm ) was 1. 32í103 μmol/L, linear detection range was 40 ~1000 μmol/L, and the modified electrode had better stability, and modified electrode had good anti-interference ability when detected the substrate. Therefore, the modified electrode can be used to detect glucose, as the third generation biosensors.%将葡萄糖氧化酶( Glucose oxidase, GOD)固定在由多壁碳纳米管( MWCNTS)和石墨烯( Graphene)构成的纳米复合材料修饰的玻碳电极上,最外层用壳聚糖( Chitosan)进行覆盖,利用循环伏安法( Cyclic Voltammetry, CV)来测量葡萄糖氧化酶在修饰电极上的电化学和电催化反应,测得电子传递速率常数ks 为0.87 s-1,电活性物质表面密度Г为1.54×10-10 mol/cm-2,动力学表观米氏常数Km 为1.32×103μmol/L,线性检测范围为:40~1000μmol/L,修饰电极有较好的稳定性,而且修饰电极在检测底物时有较好的抗干扰能力,因此,该体系修饰的电极有希望构建第三代葡萄糖生物传感器。

  14. Proceedings of the workshop on applied mathematics

    International Nuclear Information System (INIS)

    The Workshop on Applied Mathematics was held at the Cockcroft Centre, Deep River, Ontario, 1992 February 7-8. The purpose of the workshop was to provide a forum for applied mathematicians to survey the use and to discuss the future of applied mathematics at AECL Research. There were 57 participants at the workshop A total of eight 30-minute and 25 15-minute talks were presented describing mathematical techniques used in the whole range of activities at AECL Research, from numerical simulation of fluid flow through eddy current testing to quantum algebra and accelerator physics

  15. Applied linguistics - a science of culture?

    Directory of Open Access Journals (Sweden)

    Benke, Gertraud

    2003-01-01

    Full Text Available In this article, the status of applied linguistics as discipline is questioned and problems of establishing it - and other newly formed scientific enterprises like cultural science - as disciplines are discussed. This discussion is contextualized using the author's own experience as applied linguist working in (the institutional structure of Austria. Secondly, applied linguistics is presented as complementing cultural science, with both exploring at times the same phenomena albeit under different perspectives and focussing on different levels of experience. Two examples of research involving such a joint interest with different foci are discussed.

  16. ON THE EVOLUTION OF APPLIED MATHEMATICS

    Institute of Scientific and Technical Information of China (English)

    林家翘

    2003-01-01

    The recent trend in the application of mathematics to biological sciences is discussed in historical perspective. It is suggested that this new development should be regarded as a natural evolution of applied mathematics in the expansion of its scope. The mathematical concepts and methods to be used are not expected to be substantially different from those used in traditional applied mathematics. For illustration, we sketch an application of the kinetic theory of the study of dissipative systems to the study of the structure and function of protein molecules. The traditional concepts and methods of statistical physics can be successfully applied to yield predictions for comparison with empirical data.

  17. Encyclopedia of applied and computational mathematics

    CERN Document Server

    2015-01-01

    EACM is a comprehensive reference work covering the vast field of applied and computational mathematics. Applied mathematics itself accounts for at least 60 per cent of mathematics, and the emphasis on computation reflects the current and constantly growing importance of computational methods in all areas of applications. EACM emphasizes the strong links of applied mathematics with major areas of science, such as physics, chemistry, biology, and computer science, as well as specific fields like atmospheric ocean science. In addition, the mathematical input to modern engineering and technology form another core component of EACM.

  18. Applied Aeroscience and CFD Branch Overview

    Science.gov (United States)

    LeBeau, Gerald J.; Kirk, Benjamin S.

    2014-01-01

    The principal mission of NASA Johnson Space Center is Human Spaceflight. In support of the mission the Applied Aeroscience and CFD Branch has several technical competencies that include aerodynamic characterization, aerothermodynamic heating, rarefied gas dynamics, and decelerator (parachute) systems.

  19. Computational optimization techniques applied to microgrids planning

    DEFF Research Database (Denmark)

    Gamarra, Carlos; Guerrero, Josep M.

    2015-01-01

    appear along the planning process. In this context, technical literature about optimization techniques applied to microgrid planning have been reviewed and the guidelines for innovative planning methodologies focused on economic feasibility can be defined. Finally, some trending techniques and new...

  20. H-methods in applied sciences

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    2008-01-01

    The author has developed a framework for mathematical modelling within applied sciences. It is characteristic for data from 'nature and industry' that they have reduced rank for inference. It means that full rank solutions normally do not give satisfactory solutions. The basic idea of H-methods is...... cannot be improved. H-methods have been applied to wide range of fields within applied sciences. In each case, the H-methods provide with superior solutions compared to the traditional ones. A background for the H-methods is presented. The H-principle of mathematical modelling is explained. It is shown...... how the principle leads to well-defined optimisation procedures. This is illustrated in the case of linear regression. The H-methods have been applied in different areas: general linear models, nonlinear models, multi-block methods, path modelling, multi-way data analysis, growth models, dynamic...

  1. Improving Forest Operations Management through Applied Research

    Directory of Open Access Journals (Sweden)

    Mark Brown

    2011-09-01

    Full Text Available A great challenge of applied research is translating results into industry innovation. Increasingly, forest managers do not have the capacity to interpret research results but prefer to be presented with tools based on the research results that can be readily implemented. The Cooperative Research Centre (CRC for Forestry, based in Australia, has focused on delivering research results to industry partners in novel ways that can be easily applied in the field. This paper discusses six approaches taken by the CRC to help transfer applied research results to industry, including basic benchmarking curves for feller-bunchers, a toolbox for operational machine evaluation, a productivity model, a method to predict productivity with existing data, a guide for effective use of onboard computers and an optimised transportation planning tool. For each approach the paper will discuss how these approaches were developed and applied with industry collaboration.

  2. 1st Applied Electromagnetic International Conference

    CERN Document Server

    Othman, Mohd; Aziz, Mohamad; Malek, Mohd

    2015-01-01

    In this book, experts from academia and industry present the latest advances in scientific theory relating to applied electromagnetics and examine current and emerging applications particularly within the fields of electronics, communications, and computer technology. The book is based on presentations delivered at APPEIC 2014, the 1st Applied Electromagnetic International Conference, held in Bandung, Indonesia in December 2014. The conference provided an ideal platform for researchers and specialists to deliver both theoretically and practically oriented contributions on a wide range of topics relevant to the theme of nurturing applied electromagnetics for human technology. Many novel aspects were addressed, and the contributions selected for this book highlight the relevance of advances in applied electromagnetics to a variety of industrial engineering problems and identify exciting future directions for research.

  3. Applying Change of Variable to Calculus Problems

    Science.gov (United States)

    Kachapova, Farida; Kachapov, Ilias

    2011-01-01

    This article describes the technique of introducing a new variable in some calculus problems to help students master the skills of integration and evaluation of limits. This technique is algorithmic and easy to apply.

  4. ICT for AQA applied as single award

    CERN Document Server

    Wilson, Barbara

    2007-01-01

    This book has been written specifically for teachers and students following AQA's Applied AS ICT specification and covers the key elements of the units of the course, including the coursework requirements.

  5. Applied analysis mathematical methods in natural science

    CERN Document Server

    Senba, Takasi

    2004-01-01

    This book provides a general introduction to applied analysis; vectoranalysis with physical motivation, calculus of variation, Fourieranalysis, eigenfunction expansion, distribution, and so forth,including a catalogue of mathematical theories, such as basicanalysis, topological spaces, complex function theory, real analysis,and abstract analysis. This book also gives fundamental ideas ofapplied mathematics to discuss recent developments in nonlinearscience, such as mathematical modeling of reinforced random motion ofparticles, semi-conductor device equation in applied physics, andchemotaxis in

  6. The Bakhtin Circle and Applied Linguistics

    Directory of Open Access Journals (Sweden)

    Newton Duarte Molon

    2012-11-01

    Full Text Available This article aims at presenting the relations between the theoretical formulations of the Bakhtin Circle and the current discussion on the scope of the so called Applied Linguistics (AL. In order to do that, we will briefly outline the history of AL, present the main conceptions of the Bakhtin Circle‟s thought, and build possible dialogues between the theoretical formulations of the Russian thinkers and the main issues of the current debate in Applied Linguistics.

  7. [What did bachelard mean by "applied rationalism" ?].

    Science.gov (United States)

    Tiles, Mary

    2013-01-01

    Bachelard was concerned with the processes whereby scientific knowledge is acquired, including the activity of knowing subjects. He did not equate reasoning with logic but rather argued that reasoning resulted from the use of mathematics in organizing both thought and experimental practices, which is why he conceived science as applied mathematics. This had material and technical implications, for Bachelard was concerned with the element of reason inherent in technical materialism as well as the concrete reality inherent in applied rationalism. PMID:24091650

  8. Adaptive Control Applied to Financial Market Data

    Czech Academy of Sciences Publication Activity Database

    Šindelář, Jan; Kárný, Miroslav

    Strasbourg cedex: European Science Foundation, 2007, s. 1-6. [Advanced Mathematical Methods for Finance. Vídeň (AT), 17.09.2007-22.09.2007] R&D Projects: GA MŠk(CZ) 2C06001 Institutional research plan: CEZ:AV0Z10750506 Keywords : bayesian statistics * portfolio optimization * finance * adaptive control Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2007/si/sindelar-adaptive control applied to financial market data.pdf

  9. A View from Agricultural and Applied Economics

    OpenAIRE

    Henry, Mark

    2000-01-01

    Is regional science too focused on abstract models, theorizing, and methodology with weak links to policy and practice? Not from the perspective of the land grant university, where many applied economists with a regional science interest reside. The job of these applied economists is, in part, to translate the models and methods into tools for the use in understanding regional development processes and for undertaking policy analysis at the regional level.

  10. FEEDBACK LINEARISATION APPLIED ON A HYDRAULIC

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Hansen, Michael Rygaard; Pedersen, Henrik C.;

    2005-01-01

    Generally most hydraulic systems are intrensically non-linear, why applying linear control techniques typically results in conservatively dimensioned controllers to obtain stable performance. Non-linear control techniques have the potential of overcoming these problems, and in this paper the focus...... is on developing and applying several different feedback linearisation (FL) controllers to the individual servo actuators in a hydraulically driven servo robot to evaluate and compare their possiblities and limitations. This is done based on both simulation and experimental results....

  11. Computers in Some Branches of Applied Physiology .

    Directory of Open Access Journals (Sweden)

    S.S. Verma

    1994-04-01

    Full Text Available This paper reviews the applications of computers in the evaluation of different types of problems occuring in some branches of applied physiology. The recent applications of computers to perform advanced multivariate regression analysis for developing regression models in applied physiology are also highlighted. The regression models are practical significance for screening personnel in defence services, mines, industrial works, sports and the like.

  12. FEEDBACK LINEARISATION APPLIED ON A HYDRAULIC

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Hansen, Michael Rygaard; Pedersen, Henrik C.; Conrad, Finn

    Generally most hydraulic systems are intrensically non-linear, why applying linear control techniques typically results in conservatively dimensioned controllers to obtain stable performance. Non-linear control techniques have the potential of overcoming these problems, and in this paper the focus...... is on developing and applying several different feedback linearisation (FL) controllers to the individual servo actuators in a hydraulically driven servo robot to evaluate and compare their possiblities and limitations. This is done based on both simulation and experimental results....

  13. ECONOMIC ETHICS: APPLIED AND PROFESSIONAL CHARACTER

    OpenAIRE

    Ella Gordova

    2012-01-01

    In given article economic ethics are considered as set of norms of behavior of the businessman, the requirements shown by a cultural society to its style of work, to character of dialogue between participants of business, to their social shape. The conclusion becomes that economic ethics have applied character in relation to theoretical, to obschenormativnoy ethics, hence, represent section of applied ethics. On the other hand, the specific standard maintenance characteriz...

  14. Introducing the Centre for Applied Archaeology

    OpenAIRE

    Dominic Perring

    2008-01-01

    The Centre for Applied Archaeology (CAA) is a new research centre within the Institute of Archaeology, established in 2006 to develop the work of the Institute’s Field Archaeology Unit, Archaeology South-East (ASE), through the creation of a productive research environment and the building of links with academic staff members of the Institute. In this article the Director of CAA defines “applied archaeology” and describes the aims and work of the Centre.

  15. Industrial and Applied Mathematics in China

    CERN Document Server

    Li, Ta-Tsien

    2009-01-01

    This new volume introduces readers to the current topics of industrial and applied mathematics in China, with applications to material science, information science, mathematical finance and engineering. The authors utilize mathematics for the solution of problems. The purposes of the volume are to promote research in applied mathematics and computational science; further the application of mathematics to new methods and techniques useful in industry and science; and provide for the exchange of information between the mathematical, industrial, and scientific communities.

  16. The Bakhtin Circle and Applied Linguistics

    OpenAIRE

    Newton Duarte Molon; Rodolfo Vianna

    2012-01-01

    This article aims at presenting the relations between the theoretical formulations of the Bakhtin Circle and the current discussion on the scope of the so called Applied Linguistics (AL). In order to do that, we will briefly outline the history of AL, present the main conceptions of the Bakhtin Circle‟s thought, and build possible dialogues between the theoretical formulations of the Russian thinkers and the main issues of the current debate in Applied Linguistics.

  17. ECONOMIC ETHICS: APPLIED AND PROFESSIONAL CHARACTER

    Directory of Open Access Journals (Sweden)

    Ella Gordova

    2012-01-01

    Full Text Available In given article economic ethics are considered as set of norms of behavior of the businessman, the requirements shown by a cultural society to its style of work, to character of dialogue between participants of business, to their social shape. The conclusion becomes that economic ethics have applied character in relation to theoretical, to obschenormativnoy ethics, hence, represent section of applied ethics. On the other hand, the specific standard maintenance characterizes economic ethics as ethics professional.

  18. Ten years of applied labour market research at the Hanze University of Applied Sciences Groningen

    OpenAIRE

    Lieshout, Harm van

    2014-01-01

    Opening chapter of the English version of the book 'Energieke Arbeid' published by the Centre of Applied Labour Market Research and Innovation (durch abbreviation: KCA) to celebrate the 10th anniversary of applied labour market research at Hanze University of Applied Sciences. This first chapter takes a brief look back at the development of KCA over the past ten years.

  19. Applied Physics. Course Materials: Physics 111, 112, 113. Seattle Tech Prep Applied Academics Project.

    Science.gov (United States)

    South Seattle Community Coll., Washington.

    This publication contains materials for three courses in Applied Physics in the Applied Academics program at South Seattle Community College. It begins with the article, "Community College Applied Academics: The State of the Art?" (George B. Neff), which describes the characteristics, model, courses, and coordination activity that make up this…

  20. Can ILP Be Applied to Large Datasets?

    Science.gov (United States)

    Watanabe, Hiroaki; Muggleton, Stephen

    There exist large data in science and business. Existing ILP systems cannot be applied effectively for data sets with 10000 data points. In this paper, we consider a technique which can be used to apply for more than 10000 data by simplifying it. Our approach is called Approximative Generalisation and can compress several data points into one example. In case that the original examples are mixture of positive and negative examples, the resulting example is ascribed in probability values representing proportion of positiveness. Our longer term aim is to apply on large Chess endgame database to allow well controlled evaluations of the technique. In this paper we start by choosing a simple game of Noughts and Crosses and we apply mini-max backup algorithm to obtain database of examples. These outcomes are compacted using our approach and empirical results show this has advantage both in accuracy and speed. In further work we hope to apply the approach to large database of both natural and artificial domains.

  1. Eigenstress model for electrochemistry of solid surfaces.

    Science.gov (United States)

    Ma, Hongxin; Xiong, Xilin; Gao, Panpan; Li, Xi; Yan, Yu; Volinsky, Alex A; Su, Yanjing

    2016-01-01

    Thermodynamic analysis and molecular dynamics simulations were conducted to systematically study the size-dependent electrochemical response of solids. By combining the generalized Young-Laplace equation with the popular Butler-Volmer formulation, the direct influence of surface stress on solid film electrochemical reactions was isolated. A series of thermodynamic formulas were developed to describe the size-dependent electrochemical properties of the solid surface. These formulas include intrinsic surface elastic parameters, such as surface eigenstress and surface elastic modulus. Metallic films of Au, Pt, Ni, Cu and Fe were studied as examples. The anodic current density of the metal film increased, while the equilibrium potential decreased with increasing solid film thickness. PMID:27256492

  2. Electrochemistry at Nanometer-Scaled Electrodes

    Science.gov (United States)

    Watkins, John J.; Bo Zhang; White, Henry S.

    2005-01-01

    Electrochemical studies using nanometer-scaled electrodes are leading to better insights into electrochemical kinetics, interfacial structure, and chemical analysis. Various methods of preparing electrodes of nanometer dimensions are discussed and a few examples of their behavior and applications in relatively simple electrochemical experiments…

  3. Nano-scale effects in electrochemistry

    DEFF Research Database (Denmark)

    Meier, J.; Schiøtz, Jakob; Liu, Ping;

    2004-01-01

    We report combined scanning tunneling microscopy and electrochemical reactivity measurements on individual palladium nanoparticles supported on a gold surface. It is shown that the catalytic activity towards electrochemical proton reduction is enhanced by more than two orders of magnitude as the ...

  4. Electrochemistry in an acoustically levitated drop.

    Science.gov (United States)

    Chainani, Edward T; Ngo, Khanh T; Scheeline, Alexander

    2013-02-19

    Levitated drops show potential as microreactors, especially when radicals are present as reactants or products. Solid/liquid interfaces are absent or minimized, avoiding adsorption and interfacial reaction of conventional microfluidics. We report amperometric detection in an acoustically levitated drop with simultaneous ballistic addition of reactant. A gold microelectrode sensor was fabricated with a lithographic process; active electrode area was defined by a photosensitive polyimide mask. The microdisk gold working electrode of radius 19 μm was characterized using ferrocenemethanol in aqueous buffer. Using cyclic voltammetry, the electrochemically active surface area was estimated by combining a recessed microdisk electrode model with the Randles-Sevcik equation. Computer-controlled ballistic introduction of reactant droplets into the levitated drop was developed. Chronoamperometric measurements of ferrocyanide added ballistically demonstrate electrochemical monitoring using the microfabricated electrode in a levitated drop. Although concentration increases with time due to drop evaporation, the extent of concentration is predictable with a linear evaporation model. Comparison of diffusion-limited currents in pendant and levitated drops show that convection arising from acoustic levitation causes an enhancement of diffusion-limited current on the order of 16%. PMID:23351154

  5. Electrochemistry of Water-Cooled Nuclear Reactors

    International Nuclear Information System (INIS)

    This project developed a comprehensive mathematical and simulation model for calculating thermal hydraulic, electrochemical, and corrosion parameters, viz. temperature, fluid flow velocity, pH, corrosion potential, hydrogen injection, oxygen contamination, stress corrosion cracking, crack growth rate, and other important quantities in the coolant circuits of water-cooled nuclear power plants, including both Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). The model is being used to assess the three major operational problems in Pressurized Water Reactors (PWR), which include mass transport, activity transport, and the axial offset anomaly, and provide a powerful tool for predicting the accumulation of SCC damage in BWR primary coolant circuits as a function of operating history. Another achievement of the project is the development of a simulation tool to serve both as a training tool for plant operators and as an engineering test-bed to evaluate new equipment and operating strategies (normal operation, cold shut down and others). The development and implementation of the model allows us to estimate the activity transport or ''radiation fields'' around the primary loop and the vessel, as a function of the operating parameters and the water chemistry

  6. Electrochemistry of Water-Cooled Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, Dgiby; Urquidi-Macdonald, Mirna; Pitt, Jonathan

    2006-08-08

    This project developed a comprehensive mathematical and simulation model for calculating thermal hydraulic, electrochemical, and corrosion parameters, viz. temperature, fluid flow velocity, pH, corrosion potential, hydrogen injection, oxygen contamination, stress corrosion cracking, crack growth rate, and other important quantities in the coolant circuits of water-cooled nuclear power plants, including both Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). The model is being used to assess the three major operational problems in Pressurized Water Reactors (PWR), which include mass transport, activity transport, and the axial offset anomaly, and provide a powerful tool for predicting the accumulation of SCC damage in BWR primary coolant circuits as a function of operating history. Another achievement of the project is the development of a simulation tool to serve both as a training tool for plant operators and as an engineering test-bed to evaluate new equipment and operating strategies (normal operation, cold shut down and others). The development and implementation of the model allows us to estimate the activity transport or "radiation fields" around the primary loop and the vessel, as a function of the operating parameters and the water chemistry.

  7. Electrochemistry at three-phase electrodes

    OpenAIRE

    Gulaboski, Rubin

    2005-01-01

    Three-phase electrodes are seen as a powerful tool for the determination of thermodynamic and kinetic parameters of ion transfer across biomimetic membranes. In this lecture, their application and the phenomena occuring at them are described and discussed.

  8. Fundamental Material Properties Underlying Solid Oxide Electrochemistry

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Hansen, Karin Vels; Holtappels, Peter;

    2012-01-01

    electrochemical reactions take place at elevated temperatures from 300 and up to 1000 C. This has as consequence that the region around the threephase- boundary (TPB), where the electron conducting electrode, the electrolyte and the gas phase reactants meet, is the region where the electrochemical processes take...... place. The length of the TPB is a key factor even though the width and depth of the zone, in which the rate limiting reactions take place, may vary depending of the degree of the electrode materials ability to conduct both electrons and ions, i.e. the TPB zone volume depends on how good a mixed ionic...... materials in the TPB region. Also, segregations to the surfaces and interfaces of the electrode materials, which may affect the electrode reaction mechanism, are very dependent on the exact history of fabrication and operation. The positive effects of even small concentrations of nanoparticles in the...

  9. Impact Electrochemistry of Layered Transition Metal Dichalcogenides.

    Science.gov (United States)

    Lim, Chee Shan; Tan, Shu Min; Sofer, Zdeněk; Pumera, Martin

    2015-08-25

    Layered transition metal dichalcogenides (TMDs) exhibit paramount importance in the electrocatalysis of the hydrogen evolution reaction. It is crucial to determine the size of the electrocatalytic particles as well as to establish their electrocatalytic activity, which occurs at the edges of these particles. Here, we show that individual TMD (MoS2, MoSe2, WS2, or WSe2; in general MX2) nanoparticles impacting an electrode surface provide well-defined current "spikes" in both the cathodic and anodic regions. These spikes originate from direct oxidation of the nanoparticles (from M(4+) to M(6+)) at the anodic region and from the electrocatalytic currents generated upon hydrogen evolution in the cathodic region. The positive correlation between the frequency of the impacts and the concentration of TMD nanoparticles is also demonstrated here, enabling determination of the concentration of TMD nanoparticles in colloidal form. In addition, the size of individual TMD nanoparticles can be evaluated using the charge passed during every spike. The capability of detecting both the "indirect" catalytic effect of an impacting TMD nanoparticle as well as "direct" oxidation indicates that the frequency of impacts in both the "indirect" and "direct" scenarios are comparable. This suggests that all TMD nanoparticles, which are electrochemically oxidizable (thus capable of donating electrons to electrodes), are also capable of catalyzing the hydrogen reduction reaction. PMID:26241193

  10. Biomimetic electrochemistry from conducting polymers. A review

    International Nuclear Information System (INIS)

    Highlights: ► Composition and properties of conducting polymers change during reactions. ► These properties are being exploited to develop biomimetic reactive and soft devices. ► The state of the art for artificial muscles sensing working conditions was reviewed. ► Smart membranes, drug delivery devices and nervous interfaces were also reviewed. - Abstract: Films of conducting polymers in the presence of electrolytes can be oxidized or reduced by the flow of anodic or cathodic currents. Ions and solvent are exchanged during a reaction for charge and osmotic pressure balance. A reactive conducting polymer contains ions and solvent. Such variation of composition during a reaction is reminiscent of the biological processes in cells. Along changes to the composition of the material during a reaction, there are also changes to other properties, including: volume (electrochemomechanical), colour (electrochromic), stored charge (electrical storage), porosity or permselectivity (electroporosity), stored chemicals, wettability and so on. Most of those properties mimic similar property changes in organs during their functioning. These properties are being exploited to develop biomimetic reactive and soft devices: artificial muscles and polymeric actuators; supercapacitors and all organic batteries; smart membranes; electron-ion transducers; nervous interfaces and artificial synapses, or drug delivery devices. In this review we focus on the state of the art for artificial muscles, smart membranes and electron-ion transducers. The reactive nature of those devices provide them with a unique advantage related to the present days technologies: any changes in the surrounding physical or chemical variable acting on the electrochemical reaction rate will be sensed by the device while working. Working under constant current (driving signal), the evolution of the device potential or the evolution of the consumed electrical energy (sensing signals) senses and quantifies the variable increment. Driving and sensing signals are present, simultaneously, in the same two connecting wires. It is possible to prepare electrochemical devices based on conducting polymers in which there are several kinds of different sensors and one actuator embedded in one device. Examples of the tools and products, start-up companies, increasing evolution of scientific literature and patents are also presented. Scientific and technological challenges are also considered.

  11. Electrochemistry of silicon and its oxide

    CERN Document Server

    Zhang, Xiaoge Gregory

    2007-01-01

    `Dr. Zhang provides an encyclopedic compilation of the literature on the many electrochemical effects that impact the processing of silicon and its native oxide. This book will be an important reference for the silicon specialist and may have within its pages that key detail which will explain process anomalies to the MEMS practitioner.' Steve Senturia, Weller Professor of Electrical Engineering, Massachusetts Institute of Technology `This book is a must for every laboratory where semiconductor electrochemsitry is actively pursued. It is a welcome and recommended addition to ever

  12. Electrochemistry of complex combinations with organic ligands

    International Nuclear Information System (INIS)

    The electrochemical behaviour of Cd(2), Ni(2), Fe(2), Fe(3), In(3), Pb(2) complexes with organic bi-and polydentate ligands have been studied by methods of classical and alternating current polarography. Cadmium and indium complexing depending on pH value and the nature of the ligands (bipyridyl isomers, phosphoric acid esters) is discussed

  13. Electrochemistry of polyamidoamine dendrimers ester gel electrolytes

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong; MO Zunli

    2004-01-01

    This paper described the first example of polyamidoamine dendrimers ester (PAMAM) used as a gel electrolyte with a short-chain polyethylene glycol (MPEG-400) as a plasticizer. The polymer films are solid and sticky. Background cyclic voltammetry (CV) shows a potential window between +0.7 and -0.7 V vs. Ag/AgCl. The voltammetry of ferrocene and 7,7,8,8-tetracyanoquinodimethane (TCNQ) indicates that diffusion coefficients are in the range of 10-a-10-9 cm2/s.Ionic conductivities are approximately 10-6 S/cm. Similar films using dimethyl sulfoxide (DMSO) as a plasticizer instead of MPEG-400 have demonstrated ionic conductivities of 10-4 S/cra and reversible voltammetry. However, UV spectrophotometry shows that 70% of the DMSO is lost under vacuum, indicating the difficulty in quantifying the DMSO content when exposed to vacuum.

  14. Electrochemistry at Nanometer-Scaled Electrodes

    Science.gov (United States)

    Watkins, John J.; Zhang, Bo; White, Henry S.

    2005-05-01

    Advances in the fabrication of nanometer-scaled electrodes during the past decade have created a number of exciting opportunities in both physical chemistry and analytical measurements. This article describes how Pt electrodes of nanometer dimensions are synthesized and characterized in a chemical laboratory. A few examples of their applications in fundamental studies of electron-transfer mechanisms and in analytical chemistry are presented. Examples include investigations of the dependence of electron-transfer kinetics and molecular diffusion on interfacial electric fields and electrochemical detection of very small quantities of a redox-active species (zeptomole detection). The concept of comparing the electrode size to the length scales of various microscopic structures (e.g., the double layer) and chemical steps that define electrochemical reactions is emphasized. This approach allows students to understand why new phenomena appear as the electrode size is reduced to the nanometer scale. A brief overview of literature describing electrochemical experimentation with nanometer-scaled electrodes is also included.

  15. Applying a potential across a biomembrane

    DEFF Research Database (Denmark)

    Ambjörnsson, Tobias; Lomholt, Michael A; Hansen, Per Lyngs

    2007-01-01

    -tensor we find (1) in the small screening length limit, where the Debye screening length is smaller than the distance between the electrodes, the screening certifies that all electrostatic interactions are short range and the major effect of the applied potential is to decrease the membrane tension and...... increase the bending rigidity; explicit expressions for electrostatic contribution to the tension and bending rigidity are derived as a function of the applied potential, the Debye screening lengths, and the dielectric constants of the membrane and the solvents. For sufficiently large voltages the negative...... contribution to the tension is expected to cause a membrane stretching instability. (2) For the dielectric limit, i.e., no salt (and small wave vectors compared to the distance between the electrodes), when the dielectric constant on the two sides are different the applied potential induces an effective...

  16. Applied regression analysis a research tool

    CERN Document Server

    Pantula, Sastry; Dickey, David

    1998-01-01

    Least squares estimation, when used appropriately, is a powerful research tool. A deeper understanding of the regression concepts is essential for achieving optimal benefits from a least squares analysis. This book builds on the fundamentals of statistical methods and provides appropriate concepts that will allow a scientist to use least squares as an effective research tool. Applied Regression Analysis is aimed at the scientist who wishes to gain a working knowledge of regression analysis. The basic purpose of this book is to develop an understanding of least squares and related statistical methods without becoming excessively mathematical. It is the outgrowth of more than 30 years of consulting experience with scientists and many years of teaching an applied regression course to graduate students. Applied Regression Analysis serves as an excellent text for a service course on regression for non-statisticians and as a reference for researchers. It also provides a bridge between a two-semester introduction to...

  17. A First Course in Applied Mathematics

    CERN Document Server

    Rebaza, Jorge

    2012-01-01

    Explore real-world applications of selected mathematical theory, concepts, and methods Exploring related methods that can be utilized in various fields of practice from science and engineering to business, A First Course in Applied Mathematics details how applied mathematics involves predictions, interpretations, analysis, and mathematical modeling to solve real-world problems. Written at a level that is accessible to readers from a wide range of scientific and engineering fields, the book masterfully blends standard topics with modern areas of application and provides the needed foundation

  18. Functional Data Analysis Applied in Chemometrics

    DEFF Research Database (Denmark)

    Muller, Martha

    nutritional status and metabolic phenotype. We want to understand how metabolomic spectra can be analysed using functional data analysis to detect the in uence of dierent factors on specic metabolites. These factors can include, for example, gender, diet culture or dietary intervention. In Paper I we apply...... novelty of heart plots for spectral data. The important aspect of registration, also called warping or alignment, emerges from both the chemometric and statistical perspectives. In Paper III we apply functional registration in the context of biomechanics, specically to data from a juggling experiment. The...

  19. System Applies Polymer Powder To Filament Tow

    Science.gov (United States)

    Baucom, Robert M.; Snoha, John J.; Marchello, Joseph M.

    1993-01-01

    Polymer powder applied uniformly and in continuous manner. Powder-coating system applies dry polymer powder to continuous fiber tow. Unique filament-spreading technique, combined with precise control of tension on fibers in system, ensures uniform application of polymer powder to web of spread filaments. Fiber tows impregnated with dry polymer powders ("towpregs") produced for preform-weaving and composite-material-molding applications. System and process valuable to prepreg industry, for production of flexible filament-windable tows and high-temperature polymer prepregs.

  20. Belbin's Team role theory applied to musicgroups

    OpenAIRE

    Qvick, Erik Robert, 1973-

    2015-01-01

    Can R Meredith Belbin´s team role theory be applied to applied to music groups? Could team role behavior have a impact on team work and group dynamic, and also on the success and productivity of a music group? This research analyzes the application of Belbin team role theory on three music groups consisting of Icelandic professional musicians to shed light on the possibilities of such relationships. The research examine the possibilities of relationships between team role behavior and it´s im...