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Sample records for voltage measurement electrodes

  1. Electrode voltage fall and total voltage of a transient arc

    Science.gov (United States)

    Valensi, F.; Ratovoson, L.; Razafinimanana, M.; Masquère, M.; Freton, P.; Gleizes, A.

    2016-06-01

    This paper deals with an experimental study of the components of a transient arc total voltage with duration of a few tens of ms and a current peak close to 1000 A. The cathode tip is made of graphite whereas the flat anode is made either of copper or of graphite; the electrodes gap is a few mm. The analysis of the electrical parameters is supported and validated by fast imaging and by two models: the first one is a 2D physical model of the arc allowing to calculate both the plasma temperature field and the arc voltage; the second model is able to estimate the transient heating of the graphite electrode. The main aim of the study was to detect the possible change of the cathode voltage fall (CVF) during the first instants of the arc. Indeed it is expected that during the first ms the graphite cathode is rather cool and the main mechanism of the electron emission should be the field effect emission, whereas after several tens of ms the cathode is strongly heated and thermionic emission should be predominant. We have observed some change in the apparent CVF but we have shown that this apparent change can be attributed to the variation of the solid cathode resistance. On the other hand, the possible change of CVF corresponding to the transition between a ‘cold’ and a ‘hot’ cathode should be weak and could not be characterized considering our measurement uncertainty of about 2 V. The arc column voltage (ACV) was estimated by subtracting the electrode voltage fall from the total arc voltage. The experimental transient evolution of the ACV is in very good agreement with the theoretical variation predicted by the model, showing the good ability of the model to study this kind of transient arc.

  2. Current–voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution

    Directory of Open Access Journals (Sweden)

    Bernd M. Briechle

    2012-11-01

    Full Text Available We report on an experimental analysis of the charge transport through sulfur-free photochromic molecular junctions. The conductance of individual molecules contacted with gold electrodes and the current–voltage characteristics of these junctions are measured in a mechanically controlled break-junction system at room temperature and in liquid environment. We compare the transport properties of a series of molecules, labeled TSC, MN, and 4Py, with the same switching core but varying side-arms and end-groups designed for providing the mechanical and electrical contact to the gold electrodes. We perform a detailed analysis of the transport properties of TSC in its open and closed states. We find rather broad distributions of conductance values in both states. The analysis, based on the assumption that the current is carried by a single dominating molecular orbital, reveals distinct differences between both states. We discuss the appearance of diode-like behavior for the particular species 4Py that features end-groups, which preferentially couple to the metal electrode by physisorption. We show that the energetic position of the molecular orbital varies as a function of the transmission. Finally, we show for the species MN that the use of two cyano end-groups on each side considerably enhances the coupling strength compared to the typical behavior of a single cyano group.

  3. Current-voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution.

    Science.gov (United States)

    Briechle, Bernd M; Kim, Youngsang; Ehrenreich, Philipp; Erbe, Artur; Sysoiev, Dmytro; Huhn, Thomas; Groth, Ulrich; Scheer, Elke

    2012-01-01

    We report on an experimental analysis of the charge transport through sulfur-free photochromic molecular junctions. The conductance of individual molecules contacted with gold electrodes and the current-voltage characteristics of these junctions are measured in a mechanically controlled break-junction system at room temperature and in liquid environment. We compare the transport properties of a series of molecules, labeled TSC, MN, and 4Py, with the same switching core but varying side-arms and end-groups designed for providing the mechanical and electrical contact to the gold electrodes. We perform a detailed analysis of the transport properties of TSC in its open and closed states. We find rather broad distributions of conductance values in both states. The analysis, based on the assumption that the current is carried by a single dominating molecular orbital, reveals distinct differences between both states. We discuss the appearance of diode-like behavior for the particular species 4Py that features end-groups, which preferentially couple to the metal electrode by physisorption. We show that the energetic position of the molecular orbital varies as a function of the transmission. Finally, we show for the species MN that the use of two cyano end-groups on each side considerably enhances the coupling strength compared to the typical behavior of a single cyano group.

  4. Calculation and measurement of a neutral air flow velocity impacting a high voltage capacitor with asymmetrical electrodes

    Directory of Open Access Journals (Sweden)

    M. Malík

    2014-01-01

    Full Text Available This paper deals with the effects surrounding phenomenon of a mechanical force generated on a high voltage asymmetrical capacitor (the so called Biefeld-Brown effect. A method to measure this force is described and a formula to calculate its value is also given. Based on this the authors derive a formula characterising the neutral air flow velocity impacting an asymmetrical capacitor connected to high voltage. This air flow under normal circumstances lessens the generated force. In the following part this velocity is measured using Particle Image Velocimetry measuring technique and the results of the theoretically calculated velocity and the experimentally measured value are compared. The authors found a good agreement between the results of both approaches.

  5. Evidence for electronic and ionic limitations at the origin of the second voltage plateau in nickel electrodes, as deduced from impedance spectroscopy measurements

    Energy Technology Data Exchange (ETDEWEB)

    Barde, F.; Tarascon, J.M. [Laboratoire de Reactivite et de Chimie des Solides, Universite de Picardie Jules Verne, CNRS UMR 6007, F-80039 Amiens (France); Taberna, P.L. [CIRIMAT, CNRS UMR 5085, Universite Paul Sabatier, F-31062 Toulouse (France); Palacin, M.R. [Institut de Ciencia de Materials de Barcelona (CSIC), Campus UAB, E-08193 Bellaterra, Catalonia (Spain)

    2008-05-01

    The second plateau occurring during the reduction of the nickel oxyhydroxide electrode (NOE) was studied by impedance spectroscopy on a cell with a pasted electrode prepared from commercial undoped {beta}-Ni(OH){sub 2}. Measurements were performed at diverse states of reduction and a large variation of impedance upon the transition from the first to the second plateau was observed. This variation mainly takes place at low frequencies and is hence related to ionic diffusion. We observed that the impedance becomes more capacitive on the second plateau meaning that the proton diffusion is limited. These results would be consistent with the gradual formation of an insulating layer of nickel hydroxide at the interface between the NOE and the electrolyte upon reduction. Once this layer becomes compact the ionic diffusion would be hindered and forced to occur through this layer, which could explain the voltage drop observed. (author)

  6. Novel Approach to Evaluation of Charging on Semiconductor Surface by Noncontact, Electrode-Free Capacitance/Voltage Measurement

    Science.gov (United States)

    Hirae, Sadao; Kohno, Motohiro; Okada, Hiroshi; Matsubara, Hideaki; Nakatani, Ikuyoshi; Kusuda, Tatsufumi; Sakai, Takamasa

    1994-04-01

    This paper describes a novel approach to the quantitative characterization of semiconductor surface charging caused by plasma exposures and ion implantations. The problems in conventional evaluation of charging are also discussed. Following the discussions above, the necessity of unified criteria is suggested for efficient development of systems or processes without charging damage. Hence, the charging saturation voltage between a top oxide surface and substrate, V s, and the charging density per unit area per second, ρ0, should be taken as criteria of charging behavior, which effectively represent the charging characteristics of both processes. The unified criteria can be obtained from the exposure time dependence of a net charging density on the thick field oxide. In order to determine V s and ρ0, the analysis using the C-V curve measured in a noncontact method with the metal-air-insulator-semiconductor (MAIS) technique is employed. The total space-charge density in oxide and its centroid can be determined at the same time by analyzing the flat-band voltage (V fb) of the MAIS capacitor as a function of the air gap. The net charge density can be obtained by analyzing the difference between the total space-charge density in oxide before and after charging. Finally, it is shown that charge damage of the large area metal-oxide-semiconductor (MOS) capacitor can be estimated from both V s and ρ0 which are obtained from results for a thick field oxide implanted with As+ and exposed to oxygen plasma.

  7. Effects of Electrode Material on the Voltage of a Tree-Based Energy Generator.

    Directory of Open Access Journals (Sweden)

    Zhibin Hao

    Full Text Available The voltage between a standing tree and its surrounding soil is regarded as an innovative renewable energy source. This source is expected to provide a new power generation system for the low-power electrical equipment used in forestry. However, the voltage is weak, which has caused great difficulty in application. Consequently, the development of a method to increase the voltage is a key issue that must be addressed in this area of applied research. As the front-end component for energy harvesting, a metal electrode has a material effect on the level and stability of the voltage obtained. This study aimed to preliminarily ascertain the rules and mechanisms that underlie the effects of electrode material on voltage. Electrodes of different materials were used to measure the tree-source voltage, and the data were employed in a comparative analysis. The results indicate that the conductivity of the metal electrode significantly affects the contact resistance of the electrode-soil and electrode-trunk contact surfaces, thereby influencing the voltage level. The metal reactivity of the electrode has no significant effect on the voltage. However, passivation of the electrode materials markedly reduces the voltage. Suitable electrode materials are demonstrated and recommended.

  8. Evaluation of Niobium as Candidate Electrode Material for DC High Voltage Photoelectron Guns

    Science.gov (United States)

    BastaniNejad, M.; Mohamed, Abdullah; Elmustafa, A. A.; Adderley, P.; Clark, J.; Covert, S.; Hansknecht, J.; Hernandez-Garcia, C.; Poelker, M.; Mammei, R.; hide

    2012-01-01

    The field emission characteristics of niobium electrodes were compared to those of stainless steel electrodes using a DC high voltage field emission test apparatus. A total of eight electrodes were evaluated: two 304 stainless steel electrodes polished to mirror-like finish with diamond grit and six niobium electrodes (two single-crystal, two large-grain, and two fine-grain) that were chemically polished using a buffered-chemical acid solution. Upon the first application of high voltage, the best large-grain and single-crystal niobium electrodes performed better than the best stainless steel electrodes, exhibiting less field emission at comparable voltage and field strength. In all cases, field emission from electrodes (stainless steel and/or niobium) could be significantly reduced and sometimes completely eliminated, by introducing krypton gas into the vacuum chamber while the electrode was biased at high voltage. Of all the electrodes tested, a large-grain niobium electrode performed the best, exhibiting no measurable field emission (< 10 pA) at 225 kV with 20 mm cathode/anode gap, corresponding to a field strength of 18:7 MV/m.

  9. High-voltage electrode optimization towards uniform surface treatment by a pulsed volume discharge

    Science.gov (United States)

    Ponomarev, A. V.; Pedos, M. S.; Scherbinin, S. V.; Mamontov, Y. I.; Ponomarev, S. V.

    2015-11-01

    In this study, the shape and material of the high-voltage electrode of an atmospheric pressure plasma generation system were optimised. The research was performed with the goal of achieving maximum uniformity of plasma treatment of the surface of the low-voltage electrode with a diameter of 100 mm. In order to generate low-temperature plasma with the volume of roughly 1 cubic decimetre, a pulsed volume discharge was used initiated with a corona discharge. The uniformity of the plasma in the region of the low-voltage electrode was assessed using a system for measuring the distribution of discharge current density. The system's low-voltage electrode - collector - was a disc of 100 mm in diameter, the conducting surface of which was divided into 64 radially located segments of equal surface area. The current at each segment was registered by a high-speed measuring system controlled by an ARM™-based 32-bit microcontroller. To facilitate the interpretation of results obtained, a computer program was developed to visualise the results. The program provides a 3D image of the current density distribution on the surface of the low-voltage electrode. Based on the results obtained an optimum shape for a high-voltage electrode was determined. Uniformity of the distribution of discharge current density in relation to distance between electrodes was studied. It was proven that the level of non-uniformity of current density distribution depends on the size of the gap between electrodes. Experiments indicated that it is advantageous to use graphite felt VGN-6 (Russian abbreviation) as the material of the high-voltage electrode's emitting surface.

  10. Improved Lifetime High Voltage Switch Electrode.

    Science.gov (United States)

    2014-09-26

    capabilities of spark switches (e.g., saturable magnetic reactors, ignitions, and high power vacuum tubes), none has the combined high voltage, high...series impedance of the switch . Additionally, the eroded material may be deposited on internal insulators , thereby inducing pretriggering and erratic...of dry air, a typical spark switch insulating gas. -7- ENERGETIC IONS FROM ION IMPLANTER 0 0 0 0 -0 0 00000 0 0 oSUBSTRATE 0 - 0 o 0 SAMPLE= ’ 0• 0 U 0

  11. Cell voltage versus electrode potential range in aqueous supercapacitors

    Science.gov (United States)

    Dai, Zengxin; Peng, Chuang; Chae, Jung Hoon; Ng, Kok Chiang; Chen, George Z.

    2015-04-01

    Supercapacitors with aqueous electrolytes and nanostructured composite electrodes are attractive because of their high charging-discharging speed, long cycle life, low environmental impact and wide commercial affordability. However, the energy capacity of aqueous supercapacitors is limited by the electrochemical window of water. In this paper, a recently reported engineering strategy is further developed and demonstrated to correlate the maximum charging voltage of a supercapacitor with the capacitive potential ranges and the capacitance ratio of the two electrodes. Beyond the maximum charging voltage, a supercapacitor may still operate, but at the expense of a reduced cycle life. In addition, it is shown that the supercapacitor performance is strongly affected by the initial and zero charge potentials of the electrodes. Further, the differences are highlighted and elaborated between freshly prepared, aged under open circuit conditions, and cycled electrodes of composites of conducting polymers and carbon nanotubes. The first voltammetric charging-discharging cycle has an electrode conditioning effect to change the electrodes from their initial potentials to the potential of zero voltage, and reduce the irreversibility.

  12. Electrode fall voltage of arc between deion plates during direct-current interruption period

    Science.gov (United States)

    Yokomizu, Y.; Ueda, Y.; Matsumura, T.; Ichikawa, T.; Niwa, Y.; Sakaguchi, W.

    2017-07-01

    A direct-current low-voltage circuit breaker has an arc chute that consists of a stack of several metallic deion plates. The deion plate is also called a splitter plate. The function of the deion plates is to split the arc into several series short-gap arcs. This phenomenon leads to the emergence of electrode fall voltages in the arc chute, eventually contributing to rise in the total arc-voltage in the circuit breaker and to successful current-interruption. The electrode fall voltage therefore plays an important role for successful current-interruption. The present paper describes the estimation result for the electrode fall voltage {{v}\\text{ele}} of the arc between steel deion plates. The estimation is performed by using a newly devised method. This method utilizes the voltage {{v}\\text{chute}} measured across the arc chute and eventually derives {{v}\\text{ele}} on the basis of the statistics: a correlation coefficient between an arc-column electric-field strength {{E}\\text{col}} and an arc current i. Adopting the devised method enabled us to derive 19 V as {{v}\\text{ele}} . Verification is furthermore made to show the validity of the determined electrode-fall voltage, 19 V.

  13. Voltage-Induced Buckling of Dielectric Films using Fluid Electrodes

    CERN Document Server

    Tavakol, Behrouz

    2016-01-01

    Accurate and integrable control of different flows within microfluidic channels is crucial to further development of lab-on-a-chip and fully integrated adaptable structures. Here we introduce a flexible microactuator that buckles at a high deformation rate and alters the downstream fluid flow. The microactuator consists of a confined, thin, dielectric film that buckles into the microfluidic channel when exposed to voltage supplied through conductive fluid electrodes. We estimate the critical buckling voltage, and characterize the buckled shape of the actuator. Finally, we investigate the effects of frequency, flow rate, and the pressure differences on the behavior of the buckling structure and the resulting fluid flow. These results demonstrate that the voltage--induced buckling of embedded microstructures using fluid electrodes provides a means for high speed attenuation of microfluidic flow.

  14. Determination of set potential voltages for cucumber mosaic virus detection using screen printed carbon electrode

    Science.gov (United States)

    Uda, M. N. A.; Hasfalina, C. M.; Samsuzana, A. A.; Faridah, S.; Rafidah A., R.; Hashim, U.; Ariffin, Shahrul A. B.; Gopinath, Subash C. B.

    2017-03-01

    Cucumber Mosaic Virus (CMV) is a most dangerous pathogen among the cucurbit plant which it striking cucumbers, zucchinis, squashes, watermelons but it also striking to non-cucurbit such as peppers, tobaccos, celeries, beans and tomatoes. Symptoms shown by this virus when they starting to strike are very significant and at the end can kill the hosts they infected. In order to detect these viruses, biosensor such as screen-printed carbon electrode (SPCE) is developed and fixes a set potential voltage is defined using Chronoamperometry (CM) immunosensor technique. For short introduction, CM is a process which is a constant applied potential voltage between the working and reference electrode is maintained in order to create an electrons transfer for the oxidation or reduction species taking place at the surface of working electrode is measured and in this manuscript, complete details about measurement were used to finding the stable set potential voltages will be pointed out.

  15. Electrode Response in Seismo-Electric Measurements

    Science.gov (United States)

    Dietrich, M.; Devi, M. S.; Cougoulat, G.; Garambois, S.

    2014-12-01

    Seismo-electric measurements consist in recording the transient electric fields generated by seismic waves propagating in fluid-filled porous or fractured media. These electric fields are usually measured by voltage differences between two electrodes. Unfortunately, the electrode spacing and their locations on the ground surface have a direct influence on the signal-to-noise ratio of the measurements, on the recorded waveforms and on their arrival times. Using a filter theory approach and full waveform numerical simulations of the coupled seismic and electromagnetic (EM) wave propagation in porous media, we show that the co-seismic electric arrivals and the small-amplitude EM interface response can be severely distorted and/or attenuated by conventional surface electrode layouts. To this end, we have computed synthetic electrograms providing the electric potential, to allow us to determine voltage differences between two arbitrary locations of electrodes. Unlike the low-pass filter obtained by connecting two geophones in series, the filter associated with a voltage difference is shown to be a band-pass filter. As a result, not only horizontally and obliquely propagating waves but also vertically propagating waves undergo selective frequency attenuation in the 0-150 Hz frequency band used in field measurements. It also turns out that electrode spacing cannot be optimized to enhance the electric signature of typical seismic reflections and EM interface response, neither with horizontal dipoles nor with reasonably sized vertical dipoles. To circumvent this problem, we consider arrangements of 3 and 5 electrodes analogous to multilayer capacitors in electronics. We show that such arrangements are ideally described by low-pass filters preserving the quasi-plane waves corresponding to the EM interface response. However, in reality, these benefits are challenged by the imperfect coupling between the electrodes and the ground, represented by an electrode contact resistance

  16. Performance Measurement of AMTEC Electrode

    Institute of Scientific and Technical Information of China (English)

    MA; Jun-ping; HE; Hu; LI; Si-jie; TANG; Xian; LUO; Zhi-fu

    2015-01-01

    Alkali metal thermal to electric converter(AMTEC)is a direct energy conversion device capable of near-Carnot efficiencies,and has demonstrated the performance of high power density,high current low voltage.Electrode is a key component of achieving high efficiency in an AMTEC device.A RhW alloy target was used for deposition

  17. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum

    CERN Document Server

    West, Adam; DeMille, David; West, Elizabeth; Panda, Cristian; Doyle, John; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2016-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung X-rays; indeed, this is the basic principle behind the operation of standard X-ray sources. However, in laboratory setups where X-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce X-rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. We present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. We describe the characterisation of the observed X-ray radiation, its relation to the observed leakage current in the device, the steps taken to contai...

  18. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum.

    Science.gov (United States)

    West, Adam D; Lasner, Zack; DeMille, David; West, Elizabeth P; Panda, Cristian D; Doyle, John M; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2017-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung x rays; indeed, this is the basic principle behind the operation of standard x-ray sources. However, in laboratory setups where x-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce x rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. The authors present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. They describe the characterization of the observed x-ray radiation, its relation to the observed leakage current in the device, the steps taken to contain and mitigate the radiation hazard, and suggested safety guidelines.

  19. Field Emission Measurements from Niobium Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    M. BastaniNejad, P.A. Adderley, J. Clark, S. Covert, J. Hansknecht, C. Hernandez-Garcia, R. Mammei, M. Poelker

    2011-03-01

    Increasing the operating voltage of a DC high voltage photogun serves to minimize space charge induced emittance growth and thereby preserve electron beam brightness, however, field emission from the photogun cathode electrode can pose significant problems: constant low level field emission degrades vacuum via electron stimulated desorption which in turn reduces photocathode yield through chemical poisoning and/or ion bombardment and high levels of field emission can damage the ceramic insulator. Niobium electrodes (single crystal, large grain and fine grain) were characterized using a DC high voltage field emission test stand at maximum voltage -225kV and electric field gradient > 10MV/m. Niobium electrodes appear to be superior to diamond-paste polished stainless steel electrodes.

  20. Electrodic voltages accompanying stimulated bioremediation of a uranium-contaminated aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K.H.; N' Guessan, A.L.; Druhan, J.; Long, P.E.; Hubbard, S.S.; Lovley, D.R.; Banfield, J.F.

    2009-11-15

    The inability to track the products of subsurface microbial activity during stimulated bioremediation has limited its implementation. We used spatiotemporal changes in electrodic potentials (EP) to track the onset and persistence of stimulated sulfate-reducing bacteria in a uranium-contaminated aquifer undergoing acetate amendment. Following acetate injection, anomalous voltages approaching -900 mV were measured between copper electrodes within the aquifer sediments and a single reference electrode at the ground surface. Onset of EP anomalies correlated in time with both the accumulation of dissolved sulfide and the removal of uranium from groundwater. The anomalies persisted for 45 days after halting acetate injection. Current-voltage and current-power relationships between measurement and reference electrodes exhibited a galvanic response, with a maximum power density of 10 mW/m{sup 2} during sulfate reduction. We infer that the EP anomalies resulted from electrochemical differences between geochemically reduced regions and areas having higher oxidation potential. Following the period of sulfate reduction, EP values ranged from -500 to -600 mV and were associated with elevated concentrations of ferrous iron. Within 10 days of the voltage decrease, uranium concentrations rebounded from 0.2 to 0.8 {mu}M, a level still below the background value of 1.5 {mu}M. These findings demonstrate that EP measurements provide an inexpensive and minimally invasive means for monitoring the products of stimulated microbial activity within aquifer sediments and are capable of verifying maintenance of redox conditions favorable for the stability of bioreduced contaminants, such as uranium.

  1. Measurements of Plasma Potential Distribution in Segmented Electrode Hall Thruster

    Energy Technology Data Exchange (ETDEWEB)

    Y. Raitses; D. Staack; N.J. Fisch

    2001-10-16

    Use of a segmented electrode placed at the Hall thruster exit can substantially reduce the voltage potential drop in the fringing magnetic field outside the thruster channel. In this paper, we investigate the dependence of this effect on thruster operating conditions and segmented electrode configuration. A fast movable emissive probe is used to measure plasma potential in a 1 kW laboratory Hall thruster with semented electrodes made of a graphite material. Relatively small probe-induced perturbations of the thruster discharge in the vicinity of the thruster exit allow a reasonable comparison of the measured results for different thruster configurations. It is shown that the plasma potential distribution is almost not sensitive to changes of the electrode potential, but depends on the magnetic field distribution and the electrode placement.

  2. High voltage and high specific capacity dual intercalating electrode Li-ion batteries

    Science.gov (United States)

    West, William C. (Inventor); Blanco, Mario (Inventor)

    2010-01-01

    The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

  3. Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations

    National Research Council Canada - National Science Library

    E. Ramdan; N. M. Nor; K. Ramar

    2009-01-01

    Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode...

  4. TiN coated aluminum electrodes for DC high voltage electron guns

    Energy Technology Data Exchange (ETDEWEB)

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A., E-mail: aelmusta@odu.edu [Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529 and The Applied Research Center, Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Taus, Rhys [Department of Physics, Loyola Marymount University, Los Angeles, California 90045 (United States); Forman, Eric; Poelker, Matthew [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

    2015-05-15

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6Al-4V). Following gas conditioning, each TiN-coated aluminum electrode reached −225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ∼22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes.

  5. Study of the plasma interference with high voltage electrode array for space power application

    OpenAIRE

    Iwasa, Minoru; TANAKA, KOJI; Sasaki, Susumu; ODAWARA, OSAMU; 岩佐 稔; 田中 孝治; 佐々木 進; 小田原 修

    2005-01-01

    We are studying the problems associated with high voltage power systems in space. Especially we are interested in the potential distribution of the solar array that is resistant to the electrical discharge. We have carried out experiments on the interaction between the high voltage solar array and the ambient plasma. In the experiment, an array of electrodes distributed on the insulation panel was used to simulate the inter-connectors of the solar array. An electrode array without the insulat...

  6. Novel high-voltage power lateral MOSFET with adaptive buried electrodes

    Institute of Scientific and Technical Information of China (English)

    Zhang Wen-Tong; Wu Li-Juan; Qiao Ming; Luo Xiao-Rong; Zhang Bo; Li Zhao-Ji

    2012-01-01

    A new high-voltage and low-specific on-resistance (Ron,sp) adaptive buried electrode (ABE) silicon-on-insulator (SOI) power lateral MOSFET and its analytical model of the electric fields are proposed.The MOSFET features are that the electrodes are in the buried oxide (BOX) layer,the negative drain voltage Vd is divided into many partial voltages and the output to the electrodes is in the buried oxide layer and the potentials on the electrodes change linearly from the drain to the source.Because the interface silicon layer potentials are lower than the neighboring electrode potentials,the electronic potential wells are formed above the electrode regions,and the hole poteutial wells are formed in the spacing of two neighbouring electrode regions.The interface hole concentration is much higher than the electron concentration through designing the buried layer electrode potentials.Based on the interface charge enhanced dielectric layer field theory,the electric field strength in the buried layer is enhanced.The vertical electric field EI and the breakdown voltage (BV) of ABE SOI are 545 V/μm and -587 V in the 50 μm long drift region and the 1 tm thick dielectric layer,and a low Ron,sp is obtained.Furthermore,the structure also alleviates the self-heating effect (SHE).The analytical model matches the simulation results.

  7. High-voltage electrode optimization towards uniform surfacetreatment by a pulsed volume discharge

    OpenAIRE

    Ponomarev, A. V.; Pedos, M. S.; Scherbinin, S. V.; Mamontov, Y. I.; Ponomarev, Sergey Viktorovich

    2015-01-01

    In this study, the shape and material of the high-voltage electrode of an atmospheric pressure plasma generation system were optimised. The research was performed with the goal of achieving maximum uniformity of plasma treatment of the surface of the low-voltage electrode with a diameter of 100 mm. In order to generate low-temperature plasma with the volume of roughly 1 cubic decimetre, a pulsed volume discharge was used initiated with a corona discharge. The uniformity of the plasma in the r...

  8. Capacitor Voltages Measurement and Balancing in Flying Capacitor Multilevel Converters Utilizing a Single Voltage Sensor

    DEFF Research Database (Denmark)

    Farivar, Glen; Ghias, Amer M. Y. M.; Hredzak, Branislav

    2017-01-01

    This paper proposes a new method for measuring capacitor voltages in multilevel flying capacitor (FC) converters that requires only one voltage sensor per phase leg. Multiple dc voltage sensors traditionally used to measure the capacitor voltages are replaced with a single voltage sensor at the ac...... side of the phase leg. The proposed method is subsequently used to balance the capacitor voltages using only the measured ac voltage. The operation of the proposed measurement and balancing method is independent of the number of the converter levels. Experimental results presented for a five-level FC...

  9. High-voltage test and measuring techniques

    CERN Document Server

    Hauschild, Wolfgang

    2014-01-01

    It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  10. Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes

    KAUST Repository

    Wu, Kunlin

    2014-07-07

    The transition voltage of vacuum-spaced and molecular junctions constructed with Ag and Pt electrodes is investigated by non-equilibrium Green\\'s function formalism combined with density functional theory. Our calculations show that, similarly to the case of Au-vacuum-Au previously studied, the transition voltages of Ag and Pt metal-vacuum-metal junctions with atomic protrusions on the electrode surface are determined by the local density of states of the p-type atomic orbitals of the protrusion. Since the energy position of the Pt 6p atomic orbitals is higher than that of the 5p/6p of Ag and Au, the transition voltage of Pt-vacuum-Pt junctions is larger than that of both Ag-vacuum-Ag and Au-vacuum-Au junctions. When one moves to analyzing asymmetric molecular junctions constructed with biphenyl thiol as central molecule, then the transition voltage is found to depend on the specific bonding site for the sulfur atom in the thiol group. In particular agreement with experiments, where the largest transition voltage is found for Ag and the smallest for Pt, is obtained when one assumes S binding at the hollow-bridge site on the Ag/Au(111) surface and at the adatom site on the Pt(111) one. This demonstrates the critical role played by the linker-electrode binding geometry in determining the transition voltage of devices made of conjugated thiol molecules. © 2014 AIP Publishing LLC.

  11. Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes

    Science.gov (United States)

    Wu, Kunlin; Bai, Meilin; Sanvito, Stefano; Hou, Shimin

    2014-07-01

    The transition voltage of vacuum-spaced and molecular junctions constructed with Ag and Pt electrodes is investigated by non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that, similarly to the case of Au-vacuum-Au previously studied, the transition voltages of Ag and Pt metal-vacuum-metal junctions with atomic protrusions on the electrode surface are determined by the local density of states of the p-type atomic orbitals of the protrusion. Since the energy position of the Pt 6p atomic orbitals is higher than that of the 5p/6p of Ag and Au, the transition voltage of Pt-vacuum-Pt junctions is larger than that of both Ag-vacuum-Ag and Au-vacuum-Au junctions. When one moves to analyzing asymmetric molecular junctions constructed with biphenyl thiol as central molecule, then the transition voltage is found to depend on the specific bonding site for the sulfur atom in the thiol group. In particular agreement with experiments, where the largest transition voltage is found for Ag and the smallest for Pt, is obtained when one assumes S binding at the hollow-bridge site on the Ag/Au(111) surface and at the adatom site on the Pt(111) one. This demonstrates the critical role played by the linker-electrode binding geometry in determining the transition voltage of devices made of conjugated thiol molecules.

  12. Microphonics in biopotential measurements with capacitive electrodes.

    Science.gov (United States)

    Luna-Lozano, Pablo S; Pallas-Areny, Ramon

    2010-01-01

    Biopotential measurements with capacitive electrodes do not need any direct contact between electrode and skin, which saves the time devoted to expose and prepare the contact area when measuring with conductive electrodes. However, mechanical vibrations resulting from physiological functions such as respiration and cardiac contraction can change the capacitance of the electrode and affect the recordings. This transformation of mechanical vibrations into undesired electric signals is termed microphonics. We have evaluated microphonics in capacitive ECG recordings obtained from a dressed subject seated on a common chair with electrodes placed on the front side of the backrest of the chair. Depending on the softness of the backrest, the recordings may be clearly affected by the displacement of the thorax back wall due to the respiration and to the heart's mechanical activity.

  13. High-voltage test and measuring techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hauschild, Wolfgang; Lemke, Eberhard

    2014-04-01

    Reflects the unit of both HV testing and measuring technique. Intended as an ''application guide'' for the relevant IEC standards. Refers also to future trends in HV testing and measuring technique. With numerous illustrations. It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  14. Achievable peak electrode voltage reduction by neurostimulators using descending staircase currents to deliver charge.

    Science.gov (United States)

    Halpern, Mark

    2011-01-01

    This paper considers the achievable reduction in peak voltage across two driving terminals of an RC circuit when delivering charge using a stepped current waveform, comprising a chosen number of steps of equal duration, compared with using a constant current over the total duration. This work has application to the design of neurostimulators giving reduced peak electrode voltage when delivering a given electric charge over a given time duration. Exact solutions for the greatest possible peak voltage reduction using two and three steps are given. Furthermore, it is shown that the achievable peak voltage reduction, for any given number of steps is identical for simple series RC circuits and parallel RC circuits, for appropriate different values of RC. It is conjectured that the maximum peak voltage reduction cannot be improved using a more complicated RC circuit.

  15. Methods for specific electrode resistance measurement during transcranial direct current stimulation.

    Science.gov (United States)

    Khadka, Niranjan; Rahman, Asif; Sarantos, Chris; Truong, Dennis Q; Bikson, Marom

    2015-01-01

    Monitoring of electrode resistance during tDCS is considered important for tolerability and safety. Conventional resistance measurement methods do not isolate individual electrode resistance and for HD-tDCS devices, cross talk across electrodes makes concurrent resistance monitoring unreliable. We propose a novel method to monitor individual electrode resistance during tDCS, using a super-position of direct current with a test-signal (low intensity and low frequency sinusoids with electrode-specific frequencies) and a sentinel electrode (not used for DC). We developed and solved lumped-parameter models of tDCS electrodes with or without a sentinel electrode to validate this methodology. Assumptions were tested and parameterized in participants using forearm stimulation combining tDCS (2 mA) and test-signals (38 and 76 μA pk-pk at 1 Hz, 10 Hz, & 100 Hz) and an in vitro test (creating electrode failure modes). DC and AC component voltages across the electrodes were compared and participants were asked to rate subjective pain. A sentinel electrode is required to isolate electrode resistance in a two-electrode tDCS system. Cross talk aggravated with electrode proximity and resistance mismatch in multi-electrode resistance tracking could be corrected using proposed approaches. Average voltage and pain scores were not significantly different across test current intensities and frequencies. Using our developed method, a test signal can predict DC electrode resistance. Since unique test frequencies can be used at each tDCS electrode, specific electrode resistance can be resolved for any number of stimulating channels - a process made still more robust by the use of a sentinel electrode. Published by Elsevier Inc.

  16. Flexible viologen electrochromic devices with low operational voltages using reduced graphene oxide electrodes.

    Science.gov (United States)

    Palenzuela, Jesús; Viñuales, Ana; Odriozola, Ibon; Cabañero, Germán; Grande, Hans J; Ruiz, Virginia

    2014-08-27

    Reduced graphene oxide (RGO) films have been electrodeposited on indium tin oxide-coated polyethylene terephthalate (ITO-PET) substrates from graphene oxide (GO) solutions, and the resulting flexible transparent electrodes have been used in electrochromic devices of ethyl viologen (EtV(2+)). The electrochromic performance of devices with bare ITO-PET electrodes and ITO-PET coated with RGO has been compared. Under continuous cycling tests up to large voltages, the RGO film was oxidized and dispersed in the electrochromic mixture. The resulting devices, which contained GO and RGO in the electrochromic mixture, showed lower switching voltages between the colored and bleached states. This electrocatalytic activity of the solution-phase GO/RGO pair toward the electrochemical reaction of the electrochromic redox couple (the dication EtV(2+) and the radical cation EtV(+•)) allowed devices with an optical contrast higher than the contrast of those free of GO at the same applied voltage.

  17. Driving Pressure Influence in Voltage Maps Measurement Process Using Advanced Pneumatic Mapping Probe

    Directory of Open Access Journals (Sweden)

    Marek Kukucka

    2016-01-01

    Full Text Available Our paper deals with the method of the voltage-impedance map measurement process as a method useful for the electric mapping of human skin. The area of research extends from the basic research to its practical application in acupuncture skin mapping and acupuncture point localization and visualization. The problem of sufficient skin coverage and electrical contact with measuring electrodes is solved by the conventional mechanical telescopic electrodes and by the pneumatic matrix electrode probe. A 2D or 3D voltage-impedance map of skin is an output of the measuring, interpretation and evaluation process. New pneumatic construction of measuring probe was implemented to achieve a better coverage of specified skin area and get a reduced force range of the touching electrodes allowing the steady contact of the skin-electrode. A skin contact is related to the driving pressure of touching electrodes. Our paper offers experimentally measured results, voltage maps of skin on specific areas, selected measured and described acupuncture points and their applications in electro-acupuncture.

  18. Wearable Textile Electrodes for ECG Measurement

    Directory of Open Access Journals (Sweden)

    Lukas Vojtech

    2013-01-01

    Full Text Available The electrocardiogram (ECG is one of the most important parameters for monitoring of the physiological state of a person. Currently available systems for ECG monitoring are both stationary and wearable, but the comfort of the monitored person is not at a satisfactory level because these systems are not part of standard clothing. This article is therefore devoted to the development and measurement of wearable textile electrodes for ECG measurement device with high comfort for the user. The electrode material is made of electrically conductive textile. This creates a textile composite that guarantees high comfort for the user while ensuring good quality of ECG measurements. The composite is implemented by a carrier (a T-shirt with flame retardant and sensing electrodes embroidered with yarn based on a mixture of polyester coated with silver nanoparticles and cotton. The electrodes not only provide great comfort but are also antibacterial and antiallergic due to silver nanoparticles.

  19. Electrooptic Methods for Measurement of Small DC Currents at High Voltage Level

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Beatty, Neville; Skilbreid, Asbjørn Ottar

    1989-01-01

    . The measuring methods can be used both for development and supervision of electrical insulating systems. For DC measurements a system wherein the voltage is applied (across the Pockels cell) not directly but via an electrooptic circuit was developed. This circuit periodically inverts the polarity of the voltage...... fibre to an electrooptic converter. Second, by use of an electronic circuit the measured signal can be converted into a modulated frequency form for transmission along an optical fibre. These systems are described, measurement results are presented and improvements to be made in the future are outlined...... across the cell, effectively applying a square wave voltage with amplitude equal to the DC voltage to be measured. The switching circuit is based around two high voltage transistors TA, TB, with the Pockels cell electrodes being each connected to one of the transistor collectors. The transistor...

  20. Programming voltage reduction in phase change memory cells with tungsten trioxide bottom heating layer/electrode.

    Science.gov (United States)

    Rao, Feng; Song, Zhitang; Gong, Yuefeng; Wu, Liangcai; Feng, Songlin; Chen, Bomy

    2008-11-05

    A phase change memory cell with tungsten trioxide bottom heating layer/electrode is investigated. The crystalline tungsten trioxide heating layer promotes the temperature rise in the Ge(2)Sb(2)Te(5) layer which causes the reduction in the reset voltage compared to a conventional phase change memory cell. Theoretical thermal simulation and calculation for the reset process are applied to understand the thermal effect of the tungsten trioxide heating layer/electrode. The improvement in thermal efficiency of the PCM cell mainly originates from the low thermal conductivity of the crystalline tungsten trioxide material.

  1. General method to predict voltage-dependent ionic conduction in a solid electrolyte coating on electrodes

    Science.gov (United States)

    Pan, Jie; Cheng, Yang-Tse; Qi, Yue

    2015-04-01

    Understanding the ionic conduction in solid electrolytes in contact with electrodes is vitally important to many applications, such as lithium ion batteries. The problem is complex because both the internal properties of the materials (e.g., electronic structure) and the characteristics of the externally contacting phases (e.g., voltage of the electrode) affect defect formation and transport. In this paper, we developed a method based on density functional theory to study the physics of defects in a solid electrolyte in equilibrium with an external environment. This method was then applied to predict the ionic conduction in lithium fluoride (LiF), in contact with different electrodes which serve as reservoirs with adjustable Li chemical potential (μLi) for defect formation. LiF was chosen because it is a major component in the solid electrolyte interphase (SEI) formed on lithium ion battery electrodes. Seventeen possible native defects with their relevant charge states in LiF were investigated to determine the dominant defect types on various electrodes. The diffusion barrier of dominant defects was calculated by the climbed nudged elastic band method. The ionic conductivity was then obtained from the concentration and mobility of defects using the Nernst-Einstein relationship. Three regions for defect formation were identified as a function of μLi: (1) intrinsic, (2) transitional, and (3) p -type region. In the intrinsic region (high μLi, typical for LiF on the negative electrode), the main defects are Schottky pairs and in the p -type region (low μLi, typical for LiF on the positive electrode) are Li ion vacancies. The ionic conductivity is calculated to be approximately 10-31Scm-1 when LiF is in contact with a negative electrode but it can increase to 10-12Scm-1 on a positive electrode. This insight suggests that divalent cation (e.g., Mg2+) doping is necessary to improve Li ion transport through the engineered LiF coating, especially for LiF on negative

  2. Experimental validation of a high voltage pulse measurement method.

    Energy Technology Data Exchange (ETDEWEB)

    Cular, Stefan; Patel, Nishant Bhupendra; Branch, Darren W.

    2013-09-01

    This report describes X-cut lithium niobates (LiNbO3) utilization for voltage sensing by monitoring the acoustic wave propagation changes through LiNbO3 resulting from applied voltage. Direct current (DC), alternating current (AC) and pulsed voltage signals were applied to the crystal. Voltage induced shift in acoustic wave propagation time scaled quadratically for DC and AC voltages and linearly for pulsed voltages. The measured values ranged from 10 - 273 ps and 189 ps 2 ns for DC and non-DC voltages, respectively. Data suggests LiNbO3 has a frequency sensitive response to voltage. If voltage source error is eliminated through physical modeling from the uncertainty budget, the sensors U95 estimated combined uncertainty could decrease to ~0.025% for DC, AC, and pulsed voltage measurements.

  3. dc step response of induced-charge electro-osmosis between parallel electrodes at large voltages

    Science.gov (United States)

    Sugioka, Hideyuki

    2014-07-01

    Induced-charge electro-osmosis (ICEO) is important since it can be used for realizing high performance microfluidic devices. Here, we analyze the simplest problem of ion relaxation around a circular polarizable cylinder between parallel blocking electrodes in a closed cell by using a multiphysics coupled simulation technique. This technique is based on a combination of the finite-element method and finite-volume method for the Poisson-Nernst-Planck (PNP) equations having a flow term and the Stokes equation having an electric stress term. Through this analysis, we successfully demonstrate that on application of dc voltages, quadorapolar ICEO vortex flows grow during the charging time of the cylinder for both unbounded and bounded problems and decay during the charging time of the parallel electrodes only for the bounded problem using blocking electrodes. Further, by proposing a simple model that considers the two-dimensional (2D) PNP equations analytically, we successfully explain the step response time of the ICEO flow for the both unbounded and bounded problems. Furthermore, at low applied voltages, we find analytical formulations on steady diffused-ion problems and steady ICEO-flow problems and examine that our numerical results agree well with the analytical results. Moreover, by considering an ion-conserving condition with 2D Poisson-Boltzmann equations, we explain significant decrease of the maximum slip velocity at large applied voltages fairly well. We believe that our analysis will contribute greatly to the realistic designs of prospective high-performance microfluidic devices.

  4. Voltage-induced formation of accumulation layers at electrode interfaces in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Stelzl, Felix F.; Wuerfel, Uli [Freiburg Material Research Center (FMF), University of Freiburg (Germany); Fraunhofer Institute for Solar Energy Systems (ISE), Freiburg (Germany); Schulz-Gericke, Jan [Fraunhofer Institute for Solar Energy Systems (ISE), Freiburg (Germany); Crossland, Ed [Freiburg Institute of Advanced Studies (FRIAS), University of Freiburg (Germany); Ludwigs, Sabine [Freiburg Institute of Advanced Studies (FRIAS), University of Freiburg (Germany); Institute of Polymer Chemistry, University of Stuttgart (Germany)

    2012-08-15

    This work reports on organic bulk heterojunction solar cells based on poly(3-hexylthiophene) (P3HT) blended with [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) in a configuration with so-called interdigital nanoelectrodes, i.e., vertical electrodes on substrates structured in the submicrometer range. In this setup, both electrodes are in place prior to the deposition of the photoactive blend solution and therefore allow for the application of a voltage during drying of the blend. A strong correlation is observed between the photovoltaic performance of these devices and the voltage that is applied during film formation. Even the polarity of the solar cells can be controlled with this method. It is suggested that this is a consequence of a strong segregation of donor and acceptor phases at the electrode interfaces induced by the applied voltage. Further experiments on planar solar cell geometries, including a solvent-vapor treatment and the introduction of an additional layer of pure P3HT, as well as numerical simulations, are presented. All results obtained are consistent with the suggested hypothesis. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Pulsed voltage deposited lead selenide thin film as efficient counter electrode for quantum-dot-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Bin Bin [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Department of Chemical Engineering, Institute of Chemical Industry, Shaanxi Institute of Technology, Xi’an 710300 (China); Wang, Ye Feng [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Wang, Xue Qing [Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024 (China); Zeng, Jing Hui, E-mail: jhzeng@ustc.edu [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China)

    2016-04-30

    Highlights: • PbSe thin film is deposited on FTO glass by a pulse voltage electrodeposition method. • The thin film is used as counter electrode (CE) in quantum dot-sensitized solar cell. • Superior electrocatalytic activity and stability in the polysulfide electrolyte is received. • The narrow band gap characteristics and p-type conductivity enhances the cell efficiency. • An efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells. - Abstract: Lead selenide (PbSe) thin films were deposited on fluorine doped tin oxide (FTO) glass by a facile one-step pulse voltage electrodeposition method, and used as counter electrode (CE) in CdS/CdSe quantum dot-sensitized solar cells (QDSSCs). A power conversion efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells, which is much better than that of 2.39% received using Pt CEs. The enhanced performance is attributed to the extended absorption in the near infrared region, superior electrocatalytic activity and p-type conductivity with a reflection of the incident light at the back electrode in addition. The physical and chemical properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), reflectance spectra, electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The present work provides a facile pathway to an efficient CE in the QDSSCs.

  6. A consistent approach to estimate the breakdown voltage of high voltage electrodes under positive switching impulses

    Science.gov (United States)

    Arevalo, L.; Wu, D.; Jacobson, B.

    2013-08-01

    The main propose of this paper is to present a physical model of long air gap electrical discharges under positive switching impulses. The development and progression of discharges in long air gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. Experimental studies have been used to develop empirical and physical models capable to represent the streamer zone and the leader channel. The empirical ones have led to improvements in the electrical design of high voltage apparatus and insulation distances, but they cannot take into account factors associated with fundamental physics and/or the behavior of materials. The physical models have been used to describe and understand the discharge phenomena of laboratory and lightning discharges. However, because of the complex simulations necessary to reproduce real cases, they are not in widespread use in the engineering of practical applications. Hence, the aim of the work presented here is to develop a model based on physics of the discharge capable to validate and complement the existing engineering models. The model presented here proposes a new geometrical approximation for the representation of the streamer and the calculation of the accumulated electrical charge. The model considers a variable streamer region that changes with the temporal and spatial variations of the electric field. The leader channel is modeled using the non local thermo-equilibrium equations. Furthermore, statistical delays before the inception of the first corona, and random distributions to represent the tortuous nature of the path taken by the leader channel were included based on the behavior observed in experimental tests, with the intention of ensuring the discharge behaved in a realistic manner. For comparison purposes, two different gap configurations were simulated. A reasonable agreement was found between the physical model and the experimental test results.

  7. A Study on Measurement of Relative Humidity of Atmosphere Based on Dark Current from DC High-Voltage Corona Discharge of a Needle-Needle Electrode%基于针-针电极直流高压电晕放电暗电流测量大气相对湿度的研究

    Institute of Scientific and Technical Information of China (English)

    姚德新; 邹应全; 蒋沛

    2014-01-01

    To examine relationships between dark current from DC high-voltage corona discharge and relative humid-ity of atmosphere and make new methods available for measuring atmospheric humidity,a high-voltage DC needle-needle electrode was applied for discharging electricity. Meanwhile,theoretical relationships between dark current and humidity were deduced according to gas discharge theory. Then,an experimental model was built for measuring dark current,so as to measure the dark current discharged from the circuit outside the electrode in case of different input high voltage and humidity. Consistent with the rules of theoretical calculation,the results provided theoretical and experimental evidences for examining the measurement of atmospheric humidity based on the dark current from corona discharge. The results of experiment and calculation suggested that dark current from corona discharge de-clined with the decrease of input voltage and relative humidity. Under conditions of high relative humidity,dark cur-rent from corona discharge drastically increased with the rise of relative humidity.%为了研究直流高压电晕放电暗电流与大气相对湿度的关系,为大气湿度的测量提供新的方法。采用针-针电极结构的直流高压放电模型,通过气体放电理论推导了暗电流与湿度的理论关系;建立暗电流测量的实验模型,测量不同输入高压和不同湿度下电极外回路放电暗电流。实验结果与理论计算的规律一致,为电晕放电暗电流测量大气湿度的研究提供了理论和实验依据。实验和计算结果表明:电晕放电暗电流随着输入电压的降低和相对湿度的降低而减小;高相对湿度环境中,电晕放电暗电流随着相对湿度的升高而剧烈增大。

  8. THREE-ELECTRODE AIR SWITCHBOARD WITH THE GRAPHITE ELECTRODES OF KATG-50 ON VOLTAGE TO ±50 KV AND IMPULSE CURRENT BY AMPLITUDE TO ±220 KA

    Directory of Open Access Journals (Sweden)

    M. I. Baranov

    2015-04-01

    Full Text Available Purpose. Development and creation of the simplified construction of a high-voltage heavy-current air three-electrode switchboard with graphite electrodes, intended for operation in composition the powerful generator of large impulsive current of artificial of linear lightning. Methodology. Electrophysics bases of technique of high-voltage and scientific and technical bases of planning of devices of high-voltage impulsive technique. Results. Developed and made a new construction of a high-voltage heavy-current air three-electrode switchboard with the graphite electrodes of KATG-50 on nominal voltage ±50 kV. This construction of switchboard KATG-50 has been passed experimental approbation in composition the heavy-current bit chain of powerful high-voltage generator of the аperiodic impulses of current of artificial linear lightning rationed on operating foreign standards with amplitude of Im=±(200±20 кА at their duration τP=(350±35 μs at level 0,5∙Im. Originality. First in domestic practice of development and creation of high-voltage heavy-current switchboards for the generators of large impulse currents of artificial lightning the ground of necessity of the use for their basic and managing electrodes of electrical engineering graphite is carried out. Practical value. The developed and made high-voltage heavy-current switchboard of cascade-tray KATG-50 from application in its composition of graphite electrodes possesses an enhanceable working resource and enhanceable stability of wearing-out at the use of similar switchboard in the bit chain of powerful pulsed current of the imitated linear lightning.

  9. Measurement of noise and impedance of dry and wet textile electrodes, and textile electrodes with hydrogel.

    Science.gov (United States)

    Puurtinen, Merja M; Komulainen, Satu M; Kauppinen, Pasi K; Malmivuo, Jaakko A V; Hyttinen, Jari A K

    2006-01-01

    Textile sensors, when embedded into clothing, can provide new ways of monitoring physiological signals, and improve the usability and comfort of such monitoring systems in the areas of medical, occupational health and sports. However, good electrical and mechanical contact between the electrode and the skin is very important, as it often determines the quality of the signal. This paper introduces a study where the properties of dry textile electrodes, textile electrodes moistened with water, and textile electrodes covered with hydrogel were studied with five different electrode sizes. The aim was to study how the electrode size and preparation of the electrode (dry electrode/wet electrode/electrode covered with hydrogel membrane) affect the measurement noise, and the skin-electrode impedance. The measurement noise and skin-electrode impedance were determined from surface biopotential measurements. These preliminary results indicate that noise level increases as the electrode size decreases. The noise level is high in dry textile electrodes, as expected. Yet, the noise level of wet textile electrodes is quite low and similar to that of textile electrodes covered with hydrogel. Hydrogel does not seem to improve noise properties, however it may have effects on movement artifacts. Thus, it is feasible to use textile embedded sensors in physiological monitoring applications when moistening or hydrogel is applied.

  10. Atomic layer deposition encapsulated activated carbon electrodes for high voltage stable supercapacitors.

    Science.gov (United States)

    Hong, Kijoo; Cho, Moonkyu; Kim, Sang Ouk

    2015-01-28

    Operating voltage enhancement is an effective route for high energy density supercapacitors. Unfortunately, widely used activated carbon electrode generally suffers from poor electrochemical stability over 2.5 V. Here we present atomic layer deposition (ALD) encapsulation of activated carbons for high voltage stable supercapacitors. Two-nanometer-thick Al2O3 dielectric layers are conformally coated at activated carbon surface by ALD, well-maintaining microporous morphology. Resultant electrodes exhibit excellent stability at 3 V operation with 39% energy density enhancement from 2.5 V operation. Because of the protection of surface functional groups and reduction of electrolyte degradation, 74% of initial voltage was maintained 50 h after full charge, and 88% of capacitance was retained after 5000 cycles at 70 °C accelerated test, which correspond to 31 and 17% improvements from bare activated carbon, respectively. This ALD-based surface modification offers a general method to enhance electrochemical stability of carbon materials for diverse energy and environmental applications.

  11. Electrodic voltages in the presence of dissolved sulfide: Implications for monitoring natural microbial activity

    Energy Technology Data Exchange (ETDEWEB)

    Slater, L.; Ntarlagiannis, D.; Yee, N.; O' Brien, M.; Zhang, C.; Williams, K. H.

    2008-10-01

    There is growing interest in the development of new monitoring strategies for obtaining spatially extensive data diagnostic of microbial processes occurring in the earth. Open-circuit potentials arising from variable redox conditions in the fluid local-to-electrode surfaces (electrodic potentials) were recorded for a pair of silver-silver chloride electrodes in a column experiment, whereby a natural wetland soil containing a known community of sulfate reducers was continuously fed with a sulfate-rich nutrient medium. Measurements were made between five electrodes equally spaced along the column and a reference electrode placed on the column inflow. The presence of a sulfate reducing microbial population, coupled with observations of decreasing sulfate levels, formation of black precipitate (likely iron sulfide),elevated solid phase sulfide, and a characteristic sulfurous smell, suggest microbial-driven sulfate reduction (sulfide generation) in our column. Based on the known sensitivity of a silver electrode to dissolved sulfide concentration, we interpret the electrodic potentials approaching 700 mV recorded in this experiment as an indicator of the bisulfide (HS-) concentration gradients in the column. The measurement of the spatial and temporal variation in these electrodic potentials provides a simple and rapid method for monitoring patterns of relative HS- concentration that are indicative of the activity of sulfate-reducing bacteria. Our measurements have implications both for the autonomous monitoring of anaerobic microbial processes in the subsurface and the performance of self-potential electrodes, where it is critical to isolate, and perhaps quantify, electrochemical interfaces contributing to observed potentials.

  12. Semiconductor Surface Characterization Using Transverse Acoustoelectric Voltage versus Voltage Measurements.

    Science.gov (United States)

    1982-10-01

    Das, R. T. Webster and B. Davari, "SAW Characterization of Photo- Voltaic Solar Cell", Electrochemical Society Extended Abstracts, Vol. 79-1, Spring...Measurement of Carrier Generation Rate in Semiconductors", presented at the 153rd Meeting of the Electrochemical Society , Seattle, Washington, May 21-26...Ion-implanted Silicon by Surface Acoustic Waves", presented at the Electrochemical Society Meeting, May 6-11, 1979, Boston, Massachusetts. 6. P. Das, M

  13. Wall-shaped electrodes for reducing the operation voltage of polymer-stabilized blue phase liquid crystal displays

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Miyoung; Kim, Min Su; Kang, Byeong Gyun; Kim, Mi-Kyung; Yoon, Sukin; Lee, Seung Hee [Polymer BIN Fusion Research Center, Department of Polymer Nano-Science and Technology, Chonbuk National University, Chonju, Chonbuk 561-756 (Korea, Republic of); Ge Zhibing; Rao Linghui; Gauza, Sebastian; Wu, Shin-Tson, E-mail: lsh1@chonbuk.ac.k, E-mail: swu@creol.ucf.ed [College of Optics and Photonics, University of Central Florida, Orlando, FL 32816 (United States)

    2009-12-07

    Polymer-stabilized blue phase liquid crystal displays based on the Kerr effect are emerging due to their submillisecond response time, wide view and simple fabrication process. However, the conventional in-plane switching device exhibits a relatively high operating voltage because the electric fields are restricted in the vicinity of the electrode surface. To overcome this technical barrier, we propose a partitioned wall-shaped electrode configuration so that the induced birefringence is uniform between electrodes throughout the entire cell gap. Consequently, the operating voltage is reduced by {approx} 2.8x with two transistors. The responsible physical mechanisms are explained.

  14. Development of a compact neutron source by a high voltage ring electrode discharge

    Science.gov (United States)

    Watanabe, Masayuki; Shuhei Nezu Team; Akihiro Takeuchi Team

    2016-10-01

    Neutron is one of the particles in atomic nucleus. Neutron beam has many physical characteristics as follows; (a) the transmittance in a matter is high and (b) the interaction with atomic nuclei is dominant. For these reasons, the development of the neutron beam source is expected in many engineering and medical applications. However, it is still under development, because there is no compact neutron beam source. The purpose of this research is to develop the compact neutron beam source. The neutron is generated by using the inertial electrostatic confinement fusion. In this experiment, a ring-shaped electrode (cathode) is used for the convergence of the deuterium nucleus. To product the neutron by a D-D nuclear reaction, it is necessary to apply a high voltage into the glow discharge plasma. The neutron production rate is approximately 105 n/s under the condition that the cathode voltage is -15kV and discharge current is 10 mA. The neutron production rate increases with increasing the ring cathode voltage or discharge current. It will be possible to increase the number of neutrons by the stabilizing of the high voltage and high current discharge.

  15. Can undersea voltage measurements detect tsunamis?

    Digital Repository Service at National Institute of Oceanography (India)

    Manoj, C.; Kuvshinov, A.; Neetu, S.; Harinarayana, T.

    The movement of electrically conducting ocean water in the ambient geomagnetic field induces secondary electric and magnetic fields in the oceans. Ocean water transport is now routinely inferred from undersea cable voltage data. We try to answer...

  16. Scalloped electrodes for highly sensitive electrical measurements

    DEFF Research Database (Denmark)

    Vazquez Rodriguez, Patricia; Dimaki, Maria; Svendsen, Winnie Edith

    2011-01-01

    In this work we introduce a novel out-of-plane electrode with pronounced scalloped surface and high aspect ratio for electrical recordings of brain tissue in vitro, with the aim to reduce significantly the impedance of the measuring system. The profile and height of the structures is tailored...... by means of silicon fabrication techniques that sharpen them progressively and in a controlled manner. We will show that the use of the scalloped area achieves a great decrease in impedance, which is very significant for a reduction of noise in electrical measurements. The measured impedance reflects...

  17. Nanowire-Modified Three-Dimensional Electrode Enabling Low-Voltage Electroporation for Water Disinfection.

    Science.gov (United States)

    Huo, Zheng-Yang; Xie, Xing; Yu, Tong; Lu, Yun; Feng, Chao; Hu, Hong-Ying

    2016-07-19

    More than 10% of the people in the world still suffer from inadequate access to clean water. Traditional water disinfection methods (e.g., chlorination and ultraviolet radiation) include concerns about the formation of carcinogenic disinfection byproducts (DBPs), pathogen reactivation, and/or excessive energy consumption. Recently, a nanowire-assisted electroporation-disinfection method was introduced as an alternative. Here, we develop a new copper oxide nanowire (CuONW)-modified three-dimensional copper foam electrode using a facile thermal oxidation approach. An electroporation-disinfection cell (EDC) equipped with two such electrodes has achieved superior disinfection performance (>7 log removal and no detectable bacteria in the effluent). The disinfection mechanism of electroporation guarantees an exceedingly low operation voltage (1 V) and level of energy consumption (25 J L(-1)) with a short contact time (7 s). The low operation voltage avoids chlorine generation and thus reduces the potential of DBP formation. Because of irreversible electroporation damage on cell membranes, no regrowth and/or reactivation of bacteria occurs during storage after EDC treatment. Water disinfection using EDCs has great potential for practical applications.

  18. Origins of Large Voltage Hysteresis in High-Energy-Density Metal Fluoride Lithium-Ion Battery Conversion Electrodes.

    Science.gov (United States)

    Li, Linsen; Jacobs, Ryan; Gao, Peng; Gan, Liyang; Wang, Feng; Morgan, Dane; Jin, Song

    2016-03-02

    Metal fluorides and oxides can store multiple lithium ions through conversion chemistry to enable high-energy-density lithium-ion batteries. However, their practical applications have been hindered by an unusually large voltage hysteresis between charge and discharge voltage profiles and the consequent low-energy efficiency (hysteresis are rarely studied and poorly understood. Here we employ in situ X-ray absorption spectroscopy, transmission electron microscopy, density functional theory calculations, and galvanostatic intermittent titration technique to first correlate the voltage profile of iron fluoride (FeF3), a representative conversion electrode material, with evolution and spatial distribution of intermediate phases in the electrode. The results reveal that, contrary to conventional belief, the phase evolution in the electrode is symmetrical during discharge and charge. However, the spatial evolution of the electrochemically active phases, which is controlled by reaction kinetics, is different. We further propose that the voltage hysteresis in the FeF3 electrode is kinetic in nature. It is the result of ohmic voltage drop, reaction overpotential, and different spatial distributions of electrochemically active phases (i.e., compositional inhomogeneity). Therefore, the large hysteresis can be expected to be mitigated by rational design and optimization of material microstructure and electrode architecture to improve the energy efficiency of lithium-ion batteries based on conversion chemistry.

  19. Experimental Study of the Course of Threshold Current, Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

    NARCIS (Netherlands)

    Szelenyi, Andrea; Journee, Henricus Louis; Herrlich, Simon; Galistu, Gianni M.; van den Berg, Joris; van Dijk, J. Marc C.

    Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances. Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the

  20. Experimental Study of the Course of Threshold Current, Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

    NARCIS (Netherlands)

    Szelenyi, Andrea; Journee, Henricus Louis; Herrlich, Simon; Galistu, Gianni M.; van den Berg, Joris; van Dijk, J. Marc C.

    2013-01-01

    Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances. Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the cer

  1. An Optoelectronic High-voltage Probe for Measuring Impulse Voltage Distribution of HVDC Converter Valve

    Institute of Scientific and Technical Information of China (English)

    方志; 邱毓昌

    2007-01-01

    A high-voltage optoelectronic probe is developed for measuring impulse voltage distribution along thyristor units in the HVDC converter valve. The dimension of the resistive voltage divider is optimized by means of numerical compttation of electric field. A pulse frequency modulation (PFM) mode is adopted for the data transmission link because of its immunity to high-intensity electromagnetic interference. Experimental results indicate that the linearity deviation for the whole measuring system is within ± 0.15 %, and therefore it can meet requirements specified by IEC60700-1.

  2. Investigation of voltage gradient and electrode type effects on processing time, energy consumption and product quality in production of Tomato Paste by ohmic heating

    Directory of Open Access Journals (Sweden)

    M Torkian Boldaji

    2017-05-01

    Full Text Available Introduction Thermal processing has a huge impact on the textural attribute of the final food product and texture is a major factor contributing the overall quality of food. Ohmic heating is an advanced thermal processing method in which heat is internally generated within foods by passing an alternating electric current through them. Ohmic heating can volumetrically heat the entire mass of a food system, resulting in faster heating, better quality and less energy consumption than conventional thermal processing. Gradient voltage and electrode type have high effect on ohmic heating system. Materials and Methods In this study, the effect of voltage gradient and electrode type on moisture reduction time, a/b, ΔE color indexes and energy consumption were studied. For this purpose, four levels of voltage gradients (5, 7, 9 and 11 V cm-1 and four electrode types (Aluminum, Stainless steel, Brass and Graphite was investigated by ohmic heating in tomato paste processing. Tomato used in this study was purchased from a local market. The whole tomatoes were washed, crushed and mixed in a way that a red less-viscous liquid obtained (Fig. 1. This liquid was considered as tomato samples in the remainder of the article. Ohmic cooking experiments were conducted in laboratory scale ohmic heating system consists of a power supply, a variable transformer, power analyzer, a microcomputer, digital scale (GF-6000 and thermometer (Dual inpur RTD 804U (Fig. 3. The ohmic cell had a PTF cylinder with an inner diameter of 0.05 m, a length of 0.10 m and two electrodes on both side of the cell. A hole with 3 mm diameter to insert the thermocouple was created and two holes with 5 mm diameter was created on surface of cell. One of them was used for pouring tomato puree and other for exiting steam from cell. Temperature uniformity was checked during previous heating experiments by measuring the temperatures at different locations in the test cell. Ohmic heating was

  3. Time of Flight Electrochemistry: Diffusion Coefficient Measurements Using Interdigitated Array (IDA) Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fei; Kolesov, Grigory; Parkinson, Bruce A.

    2014-09-26

    A simple and straightforward method for measuring diffusion coefficients using interdigitated array (IDA) electrodes is reported. The method does not require that the exact electrode area be known but depends only the size of the gap between the IDA electrode pairs. Electroactive molecules produced at the generator electrode of the IDA by a voltage step or scan can diffuse to the collector electrode and the time delay before the current for the reverse electrochemical reaction is detected at the collector is used to calculate the diffusion coefficient. The measurement of the diffusion rate of Ru(NH3)6+2 in aqueous solution has been used as an example measuring diffusion coefficients using this method. Additionally, a digital simulation of the electrochemical response of the IDA electrodes was used to simulate the entire current/voltage/time behavior of the system and verify the experimentally measured diffusion coefficients. This work was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the Department of Energy, Office of Science, Office of Basic Energy Sciences.

  4. Energy from CO2 using capacitive electrodes--theoretical outline and calculation of open circuit voltage.

    Science.gov (United States)

    Paz-Garcia, J M; Schaetzle, O; Biesheuvel, P M; Hamelers, H V M

    2014-03-15

    Recently, a new technology has been proposed for the utilization of energy from CO2 emissions (Hamelers et al., 2014). The principle consists of controlling the dilution process of CO2-concentrated gas (e.g., exhaust gas) into CO2-dilute gas (e.g., air) thereby extracting a fraction of the released mixing energy. In this paper, we describe the theoretical fundamentals of this technology when using a pair of charge-selective capacitive electrodes. We focus on the behavior of the chemical system consisting of CO2 gas dissolved in water or monoethanolamine solution. The maximum voltage given for the capacitive cell is theoretically calculated, based on the membrane potential. The different aspects that affect this theoretical maximum value are discussed.

  5. 2-Scale topography dry electrode for biopotential measurements.

    Science.gov (United States)

    Vanlerberghe, F; De Volder, M; de Beeck, M Op; Penders, J; Reynaerts, D; Puers, R; Van Hoof, C

    2011-01-01

    The design and fabrication of a novel 2-scale topography dry electrode using macro and micro needles is presented. The macro needles enable biopotential measurements on hairy skin, the function of the micro needles is to decrease the electrode impedance even further by penetrating the outer skin layer. Also, a fast and reliable impedance characterization protocol is described. Based on this impedance measurement protocol, a comparison study is made between our dry electrode, 3 other commercial dry electrodes and a standard wet gel electrode. Promising results are already obtained with our electrodes which do not have skin piercing micro needles. For the proposed electrodes, three different conductive coatings (Ag/AgCl/Au) are compared. AgCl is found to be slightly better than Ag as coating material, while our Au coated electrodes have the highest impedance.

  6. Measuring Electrolyte Impedance and Noise Simultaneously by Triangular Waveform Voltage and Principal Component Analysis.

    Science.gov (United States)

    Xu, Shanzhi; Wang, Peng; Dong, Yonggui

    2016-04-22

    In order to measure the impedance variation process in electrolyte solutions, a method of triangular waveform voltage excitation is investigated together with principal component analysis (PCA). Using triangular waveform voltage as the excitation signal, the response current during one duty cycle is sampled to construct a measurement vector. The measurement matrix is then constructed by the measurement vectors obtained from different measurements. After being processed by PCA, the changing information of solution impedance is contained in the loading vectors while the response current and noise information is contained in the score vectors. The measurement results of impedance variation by the proposed signal processing method are independent of the equivalent impedance model. The noise-induced problems encountered during equivalent impedance calculation are therefore avoided, and the real-time variation information of noise in the electrode-electrolyte interface can be extracted at the same time. Planar-interdigitated electrodes are experimentally tested for monitoring the KCl concentration variation process. Experimental results indicate that the measured impedance variation curve reflects the changing process of solution conductivity, and the amplitude distribution of the noise during one duty cycle can be utilized to analyze the contact conditions of the electrode and electrolyte interface.

  7. Measuring Electrolyte Impedance and Noise Simultaneously by Triangular Waveform Voltage and Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    Shanzhi Xu

    2016-04-01

    Full Text Available In order to measure the impedance variation process in electrolyte solutions, a method of triangular waveform voltage excitation is investigated together with principal component analysis (PCA. Using triangular waveform voltage as the excitation signal, the response current during one duty cycle is sampled to construct a measurement vector. The measurement matrix is then constructed by the measurement vectors obtained from different measurements. After being processed by PCA, the changing information of solution impedance is contained in the loading vectors while the response current and noise information is contained in the score vectors. The measurement results of impedance variation by the proposed signal processing method are independent of the equivalent impedance model. The noise-induced problems encountered during equivalent impedance calculation are therefore avoided, and the real-time variation information of noise in the electrode-electrolyte interface can be extracted at the same time. Planar-interdigitated electrodes are experimentally tested for monitoring the KCl concentration variation process. Experimental results indicate that the measured impedance variation curve reflects the changing process of solution conductivity, and the amplitude distribution of the noise during one duty cycle can be utilized to analyze the contact conditions of the electrode and electrolyte interface.

  8. Low-voltage FIB/SEM Tomography for 3D Microstructure Evolution of LiFePO4/C Electrode

    DEFF Research Database (Denmark)

    Scipioni, Roberto; Jørgensen, Peter Stanley; Ngo, Duc-The

    2015-01-01

    This work presents an investigation of the degradation mechanisms that occur in LiFePO4/C battery electrodes during charge/discharge cycling. Impedance spectra were measured on a fresh electrode and an electrode aged by cycling. The spectra were modeled with an equivalent circuit which indicates...

  9. On-Line Voltage Stability Assessment based on PMU Measurements

    DEFF Research Database (Denmark)

    Garcia-Valle, Rodrigo; P. Da Silva, Luiz C.; Nielsen, Arne Hejde

    2009-01-01

    through statistic analysis. During the off-line analysis, a memory of high-risk situations following a pre-defined voltage stability criterion is obtained. Thereafter, basic statistics analyses are applied resulting in the definition of voltage regions. During on-line operation, voltage magnitudes......This paper presents a method for on-line monitoring of risk voltage collapse based on synchronised phasor measurement. As there is no room for intensive computation and analysis in real-time, the method is based on the combination of off-line computation and on-line monitoring, which are correlated...... of critical buses obtained by phasor measurements are monitored in relation to the risk regions. Comprehensive studies demonstrate that the proposed method could assist operators to avoid voltage collapse events, by taking preventive or emergency actions....

  10. A new low-voltage-driven GRIN liquid crystal lens with multiple ring electrodes in unequal widths.

    Science.gov (United States)

    Kao, Yung-Yuan; Chao, Paul C-P; Hsueh, Chieh-Wen

    2010-08-30

    This work is dedicated to design a novel liquid crystal (LC) lens device with multiple ring electrodes in unequal widths, in order to offer tunability on focusing quality and to lower the level of applied voltage. The number and widths of the multiple ring electrodes are pre-designed and optimized to offer the on-line tunability on individual electrode voltages to render a better refraction index distribution for focusing, as compared to the past hole-type LC lenses. The resulted refractive index distribution is expected to offer similar focusing effects based on the theory of the gradient refraction index (GRIN) lens. The transparent electrodes of this new LC lens are placed at the inner surface of the LC cell to minimize the driving voltages, in results, less than 10 V, for the same level of focusing power and an easy practical operation. A new fabrication process in the wafer level to bury bus lines is developed for generating smooth electrical fields over the lens aperture. In addition, a dielectric layer is coated between electrodes and the LC layer.

  11. A LabVIEW based experiment system for the efficient collection and analysis of cyclic voltametry and electrode charge capacity measurements.

    Science.gov (United States)

    Detlefsen, D; Hu, Z; Troyk, P R

    2006-01-01

    Cyclic voltametry and recording of stimulation electrode voltage excursions are two critical methods of measurement for understanding the performance of implantable electrodes. Because implanted electrodes cannot easily be replaced, it is necessary to have an a-priori understanding of an electrode's implanted performance and capabilities. In-vitro exhaustive tests are often needed to quantify an electrodes performance. Using commonly available equipment, the human labor cost to conduct this work is immense. Presented is an automated experiment system that is highly configurable that can efficiently conduct a battery of repeatable CV and stimulation recording measurements. Results of preparing 96 electrodes prior to an animal implantation are also discussed.

  12. Design of an integrated thermoelectric generator power converter for ultra-low power and low voltage body energy harvesters aimed at ExG active electrodes

    Science.gov (United States)

    Ataei, Milad; Robert, Christian; Boegli, Alexis; Farine, Pierre-André

    2015-10-01

    This paper describes a detailed design procedure for an efficient thermal body energy harvesting integrated power converter. The procedure is based on the examination of power loss and power transfer in a converter for a self-powered medical device. The efficiency limit for the system is derived and the converter is optimized for the worst case scenario. All optimum system parameters are calculated respecting the transducer constraints and the application form factor. Circuit blocks including pulse generators are implemented based on the system specifications and optimized converter working frequency. At this working condition, it has been demonstrated that the wide area capacitor of the voltage doubler, which provides high voltage switch gating, can be eliminated at the expense of wider switches. With this method, measurements show that 54% efficiency is achieved for just a 20 mV transducer output voltage and 30% of the chip area is saved. The entire electronic board can fit in one EEG or ECG electrode, and the electronic system can convert the electrode to an active electrode.

  13. Measuring voltage transients with an ultrafast scanning tunneling microscope

    DEFF Research Database (Denmark)

    Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

    1997-01-01

    We use an ultrafast scanning tunneling microscope to resolve propagating voltage transients in space and time. We demonstrate that the previously observed dependence of the transient signal amplitude on the tunneling resistance was only caused by the electrical sampling circuit. With a modified...... circuit, where the tunneling tip is directly connected to the current amplifier of the scanning tunneling microscope, this dependence is eliminated. Ail results can be explained with coupling through the geometrical capacitance of the tip-electrode junction. By illuminating the current...

  14. Electrode models in electrical impedance tomography

    Institute of Scientific and Technical Information of China (English)

    WANG M.

    2005-01-01

    This paper presents different views on electrode modelling, which include electrode electrochemistry models for modelling the effects of electrode-electrolyte interface, electric field electrode models for modelling electrode geometry, and electrode models for modelling the effects of electrode common mode voltage and double layer capacitance. Taking the full electrode models into consideration .in electrical impedance tomography (EIT) will greatly help the optimised approach to a good solution and further understanding of the measurement principle.

  15. A Novel High-Frequency Voltage Standing-Wave Ratio-Based Grounding Electrode Line Fault Supervision in Ultra-High Voltage DC Transmission Systems

    Directory of Open Access Journals (Sweden)

    Yufei Teng

    2017-03-01

    Full Text Available In order to improve the fault monitoring performance of grounding electrode lines in ultra-high voltage DC (UHVDC transmission systems, a novel fault monitoring approach based on the high-frequency voltage standing-wave ratio (VSWR is proposed in this paper. The VSWR is defined considering a lossless transmission line, and the characteristics of the VSWR under different conditions are analyzed. It is shown that the VSWR equals 1 when the terminal resistance completely matches the characteristic impedance of the line, and when a short circuit fault occurs on the grounding electrode line, the VSWR will be greater than 1. The VSWR will approach positive infinity under metallic earth fault conditions, whereas the VSWR in non-metallic earth faults will be smaller. Based on these analytical results, a fault supervision criterion is formulated. The effectiveness of the proposed VSWR-based fault supervision technique is verified with a typical UHVDC project established in Power Systems Computer Aided Design/Electromagnetic Transients including DC(PSCAD/EMTDC. Simulation results indicate that the proposed strategy can reliably identify the grounding electrode line fault and has strong anti-fault resistance capability.

  16. Voltage- and space-clamp errors associated with the measurement of electrotonically remote synaptic events.

    Science.gov (United States)

    Spruston, N; Jaffe, D B; Williams, S H; Johnston, D

    1993-08-01

    1. The voltage- and space-clamp errors associated with the use of a somatic electrode to measure current from dendritic synapses are evaluated using both equivalent-cylinder and morphologically realistic models of neuronal dendritic trees. 2. As a first step toward understanding the properties of synaptic current distortion under voltage-clamp conditions, the attenuation of step and sinusoidal voltage changes are evaluated in equivalent cylinder models. Demonstration of the frequency-dependent attenuation of voltage in the cable is then used as a framework for understanding the distortion of synaptic currents generated at sites remote from the somatic recording electrode and measured in the voltage-clamp recording configuration. 3. Increases in specific membrane resistivity (Rm) are shown to reduce steady-state voltage attenuation, while producing only minimal reduction in attenuation of transient voltage changes. Experimental manipulations that increase Rm therefore improve the accuracy of estimates of reversal potential for electrotonically remote synapses, but do not significantly reduce the attenuation of peak current. In addition, increases in Rm have the effect of slowing the kinetics of poorly clamped synaptic currents. 4. The effects of the magnitude of the synaptic conductance and its kinetics on the measured synaptic currents are also examined and discussed. The error in estimating parameters from measured synaptic currents is greatest for synapses with fast kinetics and large conductances. 5. A morphologically realistic model of a CA3 pyramidal neuron is used to demonstrate the generality of the conclusions derived from equivalent cylinder models. The realistic model is also used to fit synaptic currents generated by stimulation of mossy fiber (MF) and commissural/associational (C/A) inputs to CA3 neurons and to estimate the amount of distortion of these measured currents. 6. Anatomic data from the CA3 pyramidal neuron model are used to construct a

  17. Digital measurement system for the LHC klystron high voltage modulator.

    CERN Document Server

    Mikkelsen, Anders

    Accelerating voltage in the Large Hadron Collider (LHC) is created by a means of 16 superconducting standing wave RF cavities, each fed by a 400MHz/300kW continuous wave klystron amplifier. Part of the upgrade program for the LHC long shutdown one is to replace the obsolete analogue current and voltage measurement circuitry located in the high voltage bunkers by a new, digital system, using ADCs and optical fibres. A digital measurement card is implemented and integrated into the current HV modulator oil tank (floating at -58kV) and interfaced to the existing digital VME boards collecting the data for several klystrons at the ground potential. Measured signals are stored for the logging, diagnostics and post-mortem analysis purposes.

  18. An electrode polarization impedance based flow sensor for low water flow measurement

    Science.gov (United States)

    Yan, Tinghu; Sabic, Darko

    2013-06-01

    This note describes an electrode polarization impedance based flow sensor for low water flow measurement. It consists of two pairs of stainless steel electrodes set apart and inserted into a non-conductive flow tube with each pair of electrodes placed diametrically at the opposite sides. The flow sensor is modeled as a typical four-electrode system of which two electrodes are current-carrying and the other two serve as output pick ups. The polarization impedances of the two current carrying electrodes are affected by water flows resulting in changes of differential potential between the two pick-up electrodes which are separated by the same fluid. The interrogation of the two excitation electrodes with dc biased ac signals offers significantly higher sensor sensitivities to flow. The prototype flow sensor constructed for a 20 mm diameter pipeline was able to measure water flow rate as low as tested at 1.06 l h-1 and remained sensitive at a flow rate of 25.18 l h-1 when it was driven with a sinusoidal voltage at 1000 Hz with a peak ac amplitude of 2 V and a dc offset of +8 V. The nonlinear characteristics of the sensor response indicate that the sensor is more sensitive at low flows and will not be able to measure at very high flows. Additional experiments are needed to evaluate the influences of impurities, chemical species, ions constituents, conductivity and temperature over a practical range of residential water conditions, the effects of fluctuating ground signals, measurement uncertainty, power consumption, compensation of effects and practical operations. The flow sensor (principle) presented may be used as (in) a secondary sensor in combination with an existing electronic water meter to extend the low end of measurement range in residential water metering.

  19. Beam based measurement of beam position monitor electrode gains

    Directory of Open Access Journals (Sweden)

    D. L. Rubin

    2010-09-01

    Full Text Available Low emittance tuning at the Cornell Electron Storage Ring (CESR test accelerator depends on precision measurement of vertical dispersion and transverse coupling. The CESR beam position monitors (BPMs consist of four button electrodes, instrumented with electronics that allow acquisition of turn-by-turn data. The response to the beam will vary among the four electrodes due to differences in electronic gain and/or misalignment. This variation in the response of the BPM electrodes will couple real horizontal offset to apparent vertical position, and introduce spurious measurements of coupling and vertical dispersion. To alleviate this systematic effect, a beam based technique to measure the relative response of the four electrodes has been developed. With typical CESR parameters, simulations show that turn-by-turn BPM data can be used to determine electrode gains to within ∼0.1%.

  20. Characterization of interdigitated electrode structures for water contaminant detection using a hybrid voltage divider and a vector network analyzer.

    Science.gov (United States)

    Rodríguez-Delgado, José Manuel; Rodríguez-Delgado, Melissa Marlene; Mendoza-Buenrostro, Christian; Dieck-Assad, Graciano; Omar Martínez-Chapa, Sergio

    2012-01-01

    Interdigitated capacitive electrode structures have been used to monitor or actuate over organic and electrochemical media in efforts to characterize biochemical properties. This article describes a method to perform a pre-characterization of interdigitated electrode structures using two methods: a hybrid voltage divider (HVD) and a vector network analyzer (VNA). Both methodologies develop some tests under two different conditions: free air and bi-distilled water media. Also, the HVD methodology is used for other two conditions: phosphate buffer with laccase (polyphenoloxidase; EC 1.10.3.2) and contaminated media composed by a mix of phosphate buffer and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The purpose of this study is to develop and validate a characterization methodology using both, a hybrid voltage divider and VNA T-# network impedance models of the interdigitated capacitive electrode structure that will provide a shunt RC network of particular interest in detecting the amount of contamination existing in the water solution for the media conditions. This methodology should provide us with the best possible sensitivity in monitoring water contaminant media characteristics. The results show that both methods, the hybrid voltage divider and the VNA methodology, are feasible in determining impedance modeling parameters. These parameters can be used to develop electric interrogation procedures and devices such as dielectric characteristics to identify contaminant substances in water solutions.

  1. Temperature and voltage measurement in quantum systems far from equilibrium

    Science.gov (United States)

    Shastry, Abhay; Stafford, Charles A.

    2016-10-01

    We show that a local measurement of temperature and voltage for a quantum system in steady state, arbitrarily far from equilibrium, with arbitrary interactions within the system, is unique when it exists. This is interpreted as a consequence of the second law of thermodynamics. We further derive a necessary and sufficient condition for the existence of a solution. In this regard, we find that a positive temperature solution exists whenever there is no net population inversion. However, when there is a net population inversion, we may characterize the system with a unique negative temperature. Voltage and temperature measurements are treated on an equal footing: They are simultaneously measured in a noninvasive manner, via a weakly coupled thermoelectric probe, defined by requiring vanishing charge and heat dissipation into the probe. Our results strongly suggest that a local temperature measurement without a simultaneous local voltage measurement, or vice versa, is a misleading characterization of the state of a nonequilibrium quantum electron system. These results provide a firm mathematical foundation for voltage and temperature measurements far from equilibrium.

  2. A torsional sensor for MEMS-based RMS voltage measurements

    Directory of Open Access Journals (Sweden)

    J. Dittmer

    2008-05-01

    Full Text Available RF voltage measurement based on electrostatic RMS voltage-to-force conversion is an alternative method in comparison to the conventional thermal power dissipation method. It is based on a mechanical force induced by an RF voltage applied to a micro-mechanical system. For a theoretically adequate resolution and high precision measurements, the necessary geometrical dimensions of the sensor require the application of micro machining. In this contribution, the dependence between electrical and geometrical properties of different sensor designs is investigated. Based on these results, problems related to practical micro-machining and solutions with respect to possible sensor realizations are discussed. The evolution of different sensor generations is shown.

  3. Electroencephalogram measurement using polymer-based dry microneedle electrode

    Science.gov (United States)

    Arai, Miyako; Nishinaka, Yuya; Miki, Norihisa

    2015-06-01

    In this paper, we report a successful electroencephalogram (EEG) measurement using polymer-based dry microneedle electrodes. The electrodes consist of needle-shaped substrates of SU-8, a silver film, and a nanoporous parylene protective film. Differently from conventional wet electrodes, microneedle electrodes do not require skin preparation and a conductive gel. SU-8 is superior as a structural material to poly(dimethylsiloxane) (PDMS; Dow Corning Toray Sylgard 184) in terms of hardness, which was used in our previous work, and facilitates the penetration of needles through the stratum corneum. SU-8 microneedles can be successfully inserted into the skin without breaking and could maintain a sufficiently low skin-electrode contact impedance for EEG measurement. The electrodes successfully measured EEG from the frontal pole, and the quality of acquired signals was verified to be as high as those obtained using commercially available wet electrodes without any skin preparation or a conductive gel. The electrodes are readily applicable to record brain activities for a long period with little stress involved in skin preparation to the users.

  4. A simple arc column model that accounts for the relationship between voltage, current and electrode gap during VAR

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, R.L. [Sandia National Labs., Albuquerque, NM (United States). Liquid Metal Processing Lab.

    1997-02-01

    Mean arc voltage is a process parameter commonly used in vacuum arc remelting (VAR) control schemes. The response of this parameter to changes in melting current (I) and electrode gap (g{sub e}) at constant pressure may be accurately described by an equation of the form V = V{sub 0} + c{sub 1}g{sub e}I + c{sub 2}g{sub e}{sup 2} + c{sub 3}I{sup 2}, where c{sub 1}, c{sub 2} and c{sub 3} are constants, and where the non-linear terms generally constitute a relatively small correction. If the non-linear terms are ignored, the equation has the form of Ohm`s law with a constant offset (V{sub 0}), c{sub 1}g{sub e} playing the role of resistance. This implies that the arc column may be treated approximately as a simple resistor during constant current VAR, the resistance changing linearly with g{sub e}. The VAR furnace arc is known to originate from multiple cathode spot clusters situated randomly on the electrode tip surface. Each cluster marks a point of exist for conduction electrons leaving the cathode surface and entering the electrode gap. Because the spot clusters re highly localized on the cathode surface, each gives rise to an arc column that may be considered to operate independently of other local arc columns. This approximation is used to develop a model that accounts for the observed arc voltage dependence on electrode gap at constant current. Local arc column resistivity is estimated from elementary plasma physics and used to test the model for consistency by using it to predict local column heavy particle density. Furthermore, it is shown that the local arc column resistance increases as particle density increases. This is used to account for the common observation that the arc stiffens with increasing current, i.e. the arc voltage becomes more sensitive to changes in electrode gap as the melting current is increased. This explains why arc voltage is an accurate electrode gap indicator for high current VAR processes but not low current VAR processes.

  5. High impulse voltage and current measurement techniques fundamentals, measuring instruments, measuring methods

    CERN Document Server

    Schon, Klaus

    2013-01-01

    Equipment to be installed in electric power-transmission and distribution systems must pass acceptance tests with standardized high-voltage or high-current test impulses which simulate the stress on the insulation caused by external lightning discharges and switching operations in the grid. High impulse voltages and currents are also used in many other fields of science and engineering for various applications. Therefore, precise impulse-measurement techniques are necessary, either to prevent an over- or understressing of the insulation or to guarantee the effectiveness and quality of the application. The book deals with: principal generator circuits for generating high-voltage and high-current impulses measuring systems and their calibration according to IEC 60060 and IEC 62475 methods of estimating uncertainties of measurement mathematical and experimental basis for characterizing the transfer behavior of spatially extended systems used for measuring fast transients. This book is intended for engineers and ...

  6. Generated Voltage Measurement of Poly(3-Hexylthiophene) LB Films

    Science.gov (United States)

    Kushida, Masahito; Koide, Tetsuya; Hino, Koji

    The electrical conductivity of a bulky polythiophene or a bulky gold has high value. If the electrical conductivity of nanometer scale films of polythiophene or gold has high value, it is very interesting that the molecular devices are combined with these polythiophene. The Langmuir-Blodgett (LB) films were synthesized from poly(3-hexylthiophene) (P3HT), and the LB films of P3HT were doped by the electrochemical method in present study. Samples of Al/P3HT LB films/Au generated the voltage. The time dependence of the voltage generated from the Al/P3HT LB films/Au was measured. The electrochemical doping caused the generated voltage of the samples to increase.

  7. VFT PHASE VOLTAGE MEASUREMENT IN THREE-PHASE ENCLOSED GIS

    Institute of Scientific and Technical Information of China (English)

    邹建华; 岳子丁; 李洋

    2002-01-01

    The measuring of VFT phase voltage in three-phase enclosed GIS is more complex and difficult than in single-phase ones. There are 3 capacitive sensors in the measuring system, the outputs of which are with a linear relation to the three phase voltages. This linear relation is presented with a factorial matrix. Because each capacitive sensor is coupled with the electric field of three phases (A, B, and C), the electric coupling coefficients are introduced. In order to determine the matrix of electric coupling coefficients, the numerical calculation method can be used. From the discussion on two types of three-phase enclosed GIS bus, i.e. standard arrangement and biased arrangement, the dominant electric coupling coefficients are named, which can be simply and approximately calculated by an analytic expression. Finally, as an example, the waveforms of VFT phase voltage generated on a three-phase enclosed GIS bus model are displayed. When a capacitive sensor is located at the 'shortest point' of phase A (or B, or C), the VFT phase voltage VA (or VB, or VC) can almost be measured by that capacitive sensor alone.

  8. Evaluation of measurement and stimulation patterns in open electrical impedance tomography with scanning electrode.

    Science.gov (United States)

    Liu, Jinzhen; Xiong, Hui; Lin, Ling; Li, Gang

    2015-07-01

    The reconstruction quality in electrical impedance tomography is limited by the current injection amplitude, the injection and measurement patterns, and the measurement accuracy as well as the number and placement of electrodes. This paper dedicates to increase the number of independent voltage measurements by scanning electrode (SE), and design an optimal measurement and stimulation pattern for open electrical impedance tomography (OEIT). Firstly, several measurement patterns are, performed in OEIT, aiming to evaluate the right number of the measurement points for the imaged target in a certain depth. The results indicate that the image quality gets higher with the number of measurement point increased to some extent. Thus, it can guide the optimum design for the electrode system in OEIT. Secondly, through the numerical calculation and salt water tank experiment, in contrast to adjacent current injection pattern, cross-current-injection pattern achieves better reconstruction with higher imaging quality and penetration depth, and is more robust against data noise in deep domain. Lastly, the experiments also indicate that the electrode contact area affects the reconstruction quality and investigation depth. Therefore, OEIT with SE can improve the application in clinic, such as the detection and monitoring of vascular, breast, and pulmonary diseases.

  9. Developing barbed microtip-based electrode arrays for biopotential measurement.

    Science.gov (United States)

    Hsu, Li-Sheng; Tung, Shu-Wei; Kuo, Che-Hsi; Yang, Yao-Joe

    2014-07-10

    This study involved fabricating barbed microtip-based electrode arrays by using silicon wet etching. KOH anisotropic wet etching was employed to form a standard pyramidal microtip array and HF/HNO3 isotropic etching was used to fabricate barbs on these microtips. To improve the electrical conductance between the tip array on the front side of the wafer and the electrical contact on the back side, a through-silicon via was created during the wet etching process. The experimental results show that the forces required to detach the barbed microtip arrays from human skin, a polydimethylsiloxane (PDMS) polymer, and a polyvinylchloride (PVC) film were larger compared with those required to detach microtip arrays that lacked barbs. The impedances of the skin-electrode interface were measured and the performance levels of the proposed dry electrode were characterized. Electrode prototypes that employed the proposed tip arrays were implemented. Electroencephalogram (EEG) and electrocardiography (ECG) recordings using these electrode prototypes were also demonstrated.

  10. Accuracy of Plantar Electrodes Compared with Hand and Foot Electrodes in Fat-free-mass Measurement

    Directory of Open Access Journals (Sweden)

    Michel Y. Jaffrin

    2014-01-01

    Full Text Available This paper investigates the measurement of fat-free mass (FFM by bioimpedance using foot-to-foot impedancemeters (FFI with plantar electrodes measuring the foot-to-foot resistance R34 and hand-to-foot medical impedancemeters. FFM measurements were compared with corresponding data using Dual X-ray absorptiometry (DXA. Equations giving FFM were established using linear multiple regression on DXA data in a first group of 170 subjects. For validation, these equations were used on a second group of 86 subjects, and FFM were compared with DXA data; no significant difference was observed. The same protocol was repeated, but using electrodes on the right hand and foot in standing position to measure the hand to-foot resistance R13. Mean differences with DXA were higher for R13 than for R34. Effect of electrode size and feet position on resistance was also investigated. R34 decreased when electrode area increased or if feet were moved forward. It decreased if feet were moved backward. A proper configuration of contact electrodes can improve measurement accuracy and reproducibility of FFI.

  11. Volume-surface barrier discharge in dried air in three-electrode system fed by impulse high voltage with nanosecond rise time

    Science.gov (United States)

    Malashin, Maxim; Rebrov, Igor; Nebogatkin, Sergey; Sokolova, Marina; Nikitin, Alexey; Voevodin, Vadim; Krivov, Sergey

    2016-08-01

    Results of experimental investigation of a volume-surface barrier discharge in a three-electrode system under periodic impulse voltage applied to the surface discharge (SD) electrodes and a d.c. potential applied to an additional third electrode are presented. It is shown that there is a strong influence of polarity and amplitude of the d.c. potential on the direct current "extracted" out of the surface discharge plasma layer by electric field of the third electrode. The amount of charged positive species that constitute the "extracted" current prevails under positive impulse voltage for low values of the negative d.c. potential of the third electrode. The amount of negative species prevails with higher values of the positive d.c. positive of the third electrode. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  12. Multifunctional shape memory electrodes for dielectric elastomer actuators enabling high holding force and low-voltage multisegment addressing

    Science.gov (United States)

    McCoul, David; Rosset, Samuel; Besse, Nadine; Shea, Herbert

    2017-02-01

    Dielectric elastomer actuators (DEAs) are an attractive form of electromechanical transducer, possessing high energy densities, an efficient design, mechanical flexibility, high speed, and noiseless operation. They have been incorporated into a variety of elegant devices, such as microfluidic devices, tunable optics, haptic displays, and minimum-energy grippers. Dielectric elastomer minimum energy structures (DEMESs) take advantage of the prestretch of the DEA to bend a non-stretchable but flexible component to perform mechanical work. The gripper is perhaps the most intuitive type of DEMES, capable of grasping objects but with only small to moderate forces. We present a novel configuration of a DEA using electrodes made of a conductive shape-memory polymer (SMP), incorporated into the design of a gripper. The SMP electrodes allow the DEA to be rigid in the cold state, offering greater holding force than a conventional gripper. Joule heating applied to the SMP electrodes softens them, allowing for electrostatic actuation. Cooling then locks in the actuated position without the need for continued power to be supplied. Additionally, the Joule heating voltage is at least one order of magnitude less than electrostatic actuation voltages, allowing for addressing of multiple actuator elements using commercially available transistors. The shape memory gripper incorporates this addressing into its design, enabling the three segments of each finger to be controlled independently.

  13. A novel method to measure the generated voltage of a ZnO nanogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Heever, Stanley T van den; Buettner, Ulrich; Perold, Willem J, E-mail: tsvdh@sun.ac.za [Department of Electrical and Electronic Engineering, Stellenbosch University, Cnr Banghoek Road and Joubert Street, 7600, Stellenbosch (South Africa)

    2011-09-30

    A novel method to measure the output voltage of a zinc oxide nanowire nanogenerator is proposed. Various tests are performed to verify that the output voltage does indeed originate from the nanogenerator and not from environmental noise. Although noise does influence the output voltage measurements, the output voltage is easily distinguishable from the measured noise. It is also shown that the method can be used to determine the internal resistance of the nanogenerator by measuring the output voltage over different output resistors.

  14. Measurements of Electrode Skin Impedances using Carbon Rubber Electrodes - First Results

    Science.gov (United States)

    Kaufmann, Steffen; Ardelt, Gunther; Ryschka, Martin

    2013-04-01

    Non-invasive bioimpedance measurement as a tool in biomedical engineering and life sciences allows conclusions about condition and composition of living tissue. For interfacing the electronic conduction of the instrumentation and the ionic conduction of the tissue, electrodes are needed. A crucial point is the uncertainty arising from the unknown, time-varying and current density depend Electrode Skin Impedance (ESI). This work presents ESI measurements using carbon rubber electrodes on different human test subjects. The measurements for this work are carried out by employing a high accuracy Bioimpedance Measurement System (BMS) developed by the authors group, which is based on a Field Programmable Gate Array (FPGA) System on Chip (SoC). The system is able to measure magnitude and phase of complex impedances using a two- or four-electrode setup, with excitation currents from 60 μA to 5 mA in a frequency range from about 10 kHz to 300 kHz. Achieved overall measurement uncertainties are below 1%.

  15. Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations

    Directory of Open Access Journals (Sweden)

    E. Ramdan

    2009-01-01

    Full Text Available Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode. The aim of this study is to measure and calculate the earth resistance of a combined grid-multiple rods electrode buried in a two-layer soil and to confirm the simplicity and accuracy of the used formula. Approach: Soil resistivity was measured using Wenner four point method. Advanced earth resistivity measurement interpretation techniques which include graphical curve matching based on master curves and an advanced computer program based on a genetic algorithm are used in this study. Results: Based on the resistivity data, the earth resistance value was calculated using the formulas obtained from the literature. Measurements of the earth resistance of the earthing system were also conducted using the fall of potential method. Conclusion/Recommendations: A very good agreement was obtained between the measured and calculated earth resistance values. This research is the first time ever conducted where the measured earth resistance values are compared directly with the calculated earth values.

  16. Voltage Dependence of Supercapacitor Capacitance

    Directory of Open Access Journals (Sweden)

    Szewczyk Arkadiusz

    2016-09-01

    Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.

  17. A Thorax Simulator for Complex Dynamic Bioimpedance Measurements With Textile Electrodes.

    Science.gov (United States)

    Ulbrich, Mark; Muhlsteff, Jens; Teichmann, Daniel; Leonhardt, Steffen; Walter, Marian

    2015-06-01

    Bioimpedance measurements on the human thorax are suitable for assessment of body composition or hemodynamic parameters, such as stroke volume; they are non-invasive, easy in application and inexpensive. When targeting personal healthcare scenarios, the technology can be integrated into textiles to increase ease, comfort and coverage of measurements. Bioimpedance is generally measured using two electrodes injecting low alternating currents (0.5-10 mA) and two additional electrodes to measure the corresponding voltage drop. The impedance is measured either spectroscopically (bioimpedance spectroscopy, BIS) between 5 kHz and 1 MHz or continuously at a fixed frequency around 100 kHz (impedance cardiography, ICG). A thorax simulator is being developed for testing and calibration of bioimpedance devices and other new developments. For the first time, it is possible to mimic the complete time-variant properties of the thorax during an impedance measurement. This includes the dynamic real part and dynamic imaginary part of the impedance with a peak-to-peak value of 0.2 Ω and an adjustable base impedance (24.6 Ω ≥ Z0 ≥ 51.6 Ω). Another novelty is adjustable complex electrode-skin contact impedances for up to 8 electrodes to evaluate bioimpedance devices in combination with textile electrodes. In addition, an electrocardiographic signal is provided for cardiographic measurements which is used in ICG devices. This provides the possibility to generate physiologic impedance changes, and in combination with an ECG, all parameters of interest such as stroke volume (SV), pre-ejection period (PEP) or extracellular resistance (Re) can be simulated. The speed of all dynamic signals can be altered. The simulator was successfully tested with commercially available BIS and ICG devices and the preset signals are measured with high correlation (r = 0.996).

  18. Means to remove electrode contamination effect of Langmuir probe measurement in space

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, K.-I.; Lee, C. H.; Fang, H. K.; Cheng, C. Z. [Plasma and Space Science Center, National Cheng Kung University, No.1 Ta-Hsueh Rd., Tainan 70101, Taiwan (China)

    2012-05-15

    Precaution to remove the serious effect of electrode contamination in Langmuir probe experiments has not been taken in many space measurements because the effect is either not understood or ignored. We stress here that one should pay extra attention to the electrode contamination effect to get accurate and reliable plasma measurements so that the long time effort for sounding rocket/satellite missions does not end in vain or becomes less fruitful. In this paper, we describe two main features of voltage-current characteristic curves associated with the contaminated Langmuir probe, which are predicted from the equivalent circuit model, which we proposed in 1970's. We then show that fast sweeping dc Langmuir probes can give reliable results in the steady state regime. The fast sweeping probe can also give reliable results in transient situations such as satellite moves through plasma bubble in the ionosphere where the electron density drastically changes. This fact was first confirmed in our laboratory experiment.

  19. Spatially resolved voltage, current and electrochemical impedance spectroscopy measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gerteisen, D.; Kurz, T.; Schwager, M.; Hebling, C. [Fraunhofer Institute for Solar Energy Systems ISE, Freiburg im Breisgau (Germany); Merida, W. [Clean Energy Research Centre, University of British Columbia, Vancouver, BC (Canada); Lupotto, P. [Materials Mates Italia, Milano (Italy)

    2011-04-15

    In this work a 50-channel characterisation system for PEMFCs is presented. The system is capable of traditional electrochemical measurements (e.g. staircase voltammetry, chronoamperometry and cyclic voltammetry), and concurrent EIS measurements. Unlike previous implementations, this system relies on dedicated potentiostats for current and voltage control, and independent frequency response analysers (FRAs) at each channel. Segmented fuel cell hardware is used to illustrate the system's flexibility and capabilities. The results here include steady-state data for cell characterisation under galvanostatic and potentiostatic control as well as spatially resolved impedance spectra. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Determination of Contact Potential Difference by the Kelvin Probe (Part II) 2. Measurement System by Involving the Composite Bucking Voltage

    Science.gov (United States)

    Vilitis, O.; Rutkis, M.; Busenbergs, J.; Merkulovs, D.

    2016-12-01

    The present research is devoted to creation of a new low-cost miniaturised measurement system for determination of potential difference in real time and with high measurement resolution. Furthermore, using the electrode of the reference probe, Kelvin method leads to both an indirect measurement of electronic work function or contact potential of the sample and measurement of a surface potential for insulator type samples. The bucking voltage in this system is composite and comprises a periodically variable component. The necessary steps for development of signal processing and tracking are described in detail.

  1. Numerical simulation of particle dynamics in an orifice-electrode system. Application to counting and sizing by impedance measurement.

    Science.gov (United States)

    Isèbe, Damien; Nérin, Philippe

    2013-04-01

    This paper describes how to numerically tackle the problem of counting and sizing particles by impedance measurement in an orifice-electrode system. The model allows to simulate the particle dynamics submitted to strong hydrodynamic stresses through a microorifice and to compute the voltage pulses generated by the modification of the inner dielectric medium. This approach gives important information about particles size distribution and allows to quantify the role of trajectory and orientation of particles on the size measurement.

  2. Measurement of microchannel fluidic resistance with a standard voltage meter.

    Science.gov (United States)

    Godwin, Leah A; Deal, Kennon S; Hoepfner, Lauren D; Jackson, Louis A; Easley, Christopher J

    2013-01-03

    A simplified method for measuring the fluidic resistance (R(fluidic)) of microfluidic channels is presented, in which the electrical resistance (R(elec)) of a channel filled with a conductivity standard solution can be measured and directly correlated to R(fluidic) using a simple equation. Although a slight correction factor could be applied in this system to improve accuracy, results showed that a standard voltage meter could be used without calibration to determine R(fluidic) to within 12% error. Results accurate to within 2% were obtained when a geometric correction factor was applied using these particular channels. When compared to standard flow rate measurements, such as meniscus tracking in outlet tubing, this approach provided a more straightforward alternative and resulted in lower measurement error. The method was validated using 9 different fluidic resistance values (from ∼40 to 600kPa smm(-3)) and over 30 separately fabricated microfluidic devices. Furthermore, since the method is analogous to resistance measurements with a voltage meter in electrical circuits, dynamic R(fluidic) measurements were possible in more complex microfluidic designs. Microchannel R(elec) was shown to dynamically mimic pressure waveforms applied to a membrane in a variable microfluidic resistor. The variable resistor was then used to dynamically control aqueous-in-oil droplet sizes and spacing, providing a unique and convenient control system for droplet-generating devices. This conductivity-based method for fluidic resistance measurement is thus a useful tool for static or real-time characterization of microfluidic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Thermo-voltage measurements of atomic contacts at low temperature

    Directory of Open Access Journals (Sweden)

    Ayelet Ofarim

    2016-05-01

    Full Text Available We report the development of a novel method to determine the thermopower of atomic-sized gold contacts at low temperature. For these measurements a mechanically controllable break junction (MCBJ system is used and a laser source generates a temperature difference of a few kelvins across the junction to create a thermo-voltage. Since the temperature difference enters directly into the Seebeck coefficient S = −ΔV/ΔT, the determination of the temperature plays an important role. We present a method for the determination of the temperature difference using a combination of a finite element simulation, which reveals the temperature distribution of the sample, and the measurement of the resistance change due to laser heating of sensor leads on both sides next to the junction. Our results for the measured thermopower are in agreement with recent reports in the literature.

  4. Measurement of a power system nominal voltage, frequency and voltage flicker parameters

    Energy Technology Data Exchange (ETDEWEB)

    Alkandari, A.M. [College of Technological Studies, Electrical Engineering Technology Department, Shwiekh (Kuwait); Soliman, S.A. [Electrical Power and Machines Department, Misr University for Science and Technology, Cairo (Egypt)

    2009-09-15

    We present, in this paper, an approach for identifying the frequency and amplitude of voltage flicker signal that imposed on the nominal voltage signal, as well as the amplitude and frequency of the nominal signal itself. The proposed algorithm performs the estimation in two steps; in the first step the original voltage signal is shifted forward and backward by an integer number of sample, one sample in this paper. The new generated signals from such a shift together with the original one is used to estimate the amplitude of the original signal voltage that composed of the nominal voltage and flicker voltage. The average of this amplitude gives the amplitude of the nominal voltage; this amplitude is subtracted from the original identified signal amplitude to obtain the samples of the flicker voltage. In the second step, the argument of the signal is calculated by simply dividing the magnitude of signal sample with the estimated amplitude in the first step. Calculating the arccosine of the argument, the frequency of the nominal signal as well as the phase angle can be computing using the least error square estimation algorithm. Simulation examples are given within the text to show the features of the proposed approach. (author)

  5. Lifetime of Ionic Vacancy Created in Redox Electrode Reaction Measured by Cyclotron MHD Electrode

    Science.gov (United States)

    Sugiyama, Atsushi; Morimoto, Ryoichi; Osaka, Tetsuya; Mogi, Iwao; Asanuma, Miki; Miura, Makoto; Oshikiri, Yoshinobu; Yamauchi, Yusuke; Aogaki, Ryoichi

    2016-01-01

    The lifetimes of ionic vacancies created in ferricyanide-ferrocyanide redox reaction have been first measured by means of cyclotron magnetohydrodynamic electrode, which is composed of coaxial cylinders partly exposed as electrodes and placed vertically in an electrolytic solution under a vertical magnetic field, so that induced Lorentz force makes ionic vacancies circulate together with the solution along the circumferences. At low magnetic fields, due to low velocities, ionic vacancies once created become extinct on the way of returning, whereas at high magnetic fields, in enhanced velocities, they can come back to their initial birthplaces. Detecting the difference between these two states, we can measure the lifetime of ionic vacancy. As a result, the lifetimes of ionic vacancies created in the oxidation and reduction are the same, and the intrinsic lifetime is 1.25 s, and the formation time of nanobubble from the collision of ionic vacancies is 6.5 ms. PMID:26791269

  6. Developing Barbed Microtip-Based Electrode Arrays for Biopotential Measurement

    Directory of Open Access Journals (Sweden)

    Li-Sheng Hsu

    2014-07-01

    Full Text Available This study involved fabricating barbed microtip-based electrode arrays by using silicon wet etching. KOH anisotropic wet etching was employed to form a standard pyramidal microtip array and HF/HNO3 isotropic etching was used to fabricate barbs on these microtips. To improve the electrical conductance between the tip array on the front side of the wafer and the electrical contact on the back side, a through-silicon via was created during the wet etching process. The experimental results show that the forces required to detach the barbed microtip arrays from human skin, a polydimethylsiloxane (PDMS polymer, and a polyvinylchloride (PVC film were larger compared with those required to detach microtip arrays that lacked barbs. The impedances of the skin-electrode interface were measured and the performance levels of the proposed dry electrode were characterized. Electrode prototypes that employed the proposed tip arrays were implemented. Electroencephalogram (EEG and electrocardiography (ECG recordings using these electrode prototypes were also demonstrated.

  7. Nanostructured micro-electrode arrays for electrophysiological measurements

    DEFF Research Database (Denmark)

    Wierzbicki, Rafal Dominik

    -dimensional electrode arrays with features able to penetrate cell membrane are currently investigated by various groups. While a number of experimental setups have been recently developed, the question remains whether the nanostructure is in fact penetrating the cellular membrane, and if the measurements are indeed......Potential and electrochemical measurements of biological cell electroactivity is crucial in cell biology research. The traditional technique with a micrometer-sharp glass pipette equipped with a metal wire within its core or electrically conductive saline solution allows extracellular, ion......-channel and intracellular measurements. In applications that require multichannel measurements, this approach is, however, impractical and planar arrays of metal electrodes are usually employed. Yet, with planar geometry, they allow extracellular measurements only. Several approaches to developing functional three...

  8. Gate voltage and drain current stress instabilities in amorphous In–Ga–Zn–O thin-film transistors with an asymmetric graphene electrode

    Directory of Open Access Journals (Sweden)

    Joonwoo Kim

    2015-09-01

    Full Text Available The gate voltage and drain current stress instabilities in amorphous In–Ga–Zn–O thin-film transistors (a-IGZO TFTs having an asymmetric graphene electrode structure are studied. A large positive shift in the threshold voltage, which is well fitted to a stretched-exponential equation, and an increase in the subthreshold slope are observed when drain current stress is applied. This is due to an increase in temperature caused by power dissipation in the graphene/a-IGZO contact region, in addition to the channel region, which is different from the behavior in a-IGZO TFTs with a conventional transparent electrode.

  9. Enhanced Open-Circuit Voltage in Visible Quantum Dot Photovoltaics by Engineering of Carrier-Collecting Electrodes

    KAUST Repository

    Wang, Xihua

    2011-10-26

    Colloidal quantum dots (CQDs) enable multijunction solar cells using a single material programmed using the quantum size effect. Here we report the systematic engineering of 1.6 eV PbS CQD solar cells, optimal as the front cell responsible for visible-wavelength harvesting in tandem photovoltaics. We rationally optimize each of the device\\'s collecting electrodes-the heterointerface with electron-accepting TiO2 and the deep-work-function hole-collecting MoO3 for ohmic contact-for maximum efficiency. We report an open-circuit voltage of 0.70 V, the highest observed in a colloidal quantum dot solar cell operating at room temperature. We report an AM1.5 solar power conversion efficiency of 3.5%, the highest observed in >1.5 eV bandgap CQD PV device. © 2011 American Chemical Society.

  10. A Voltage Instability Predictor Using Local Area Measurements. VIP++

    Energy Technology Data Exchange (ETDEWEB)

    Warland, Leif

    2002-07-01

    There has been a pressure to operate power systems closer to their security limits. This has partially been due to financial imperatives following the deregulating of markets. Other practical difficulties have been obtaining authorization from regulatory bodies to build power plants and transmission lines. In this situation it is essential to monitor the system and to have tools that can predict the distance to the point of collapse (PoC). Much effort has been put into research of the phenomenon voltage collapse, and many approaches have been explored. Both dynamic and steady-state behavior have been studied thoroughly, though very few protection and control schemes have been implemented. In this dissertation the possibility of an index based on local area measurements have been explored. Voltage stability can be classified as either a transient or a long-term stability problem, and the index proposed in this dissertation is based on long-term dynamics. The VIP algorithm is a method that uses the maximum load ability of a transmission network as the PoC, thus by estimating a Thevenin equivalent the method can track the distance to the PoC as this occurs when the two impedances are equal in absolute value. The problem of the VIP algorithm is that it is based on a system with two equations and four unknowns, thus it is not observable. In order to make it observable the assumption of constant Thevenin equivalent between two sets of measurements is made. When this is not the case the method will estimate a Thevenin impedance of the same size as the measured load impedance, but with a negative sign. Changes in the Thevenin equivalent can be traced to both angle variation in a remote generator area or to variations in load impedances on nearby buses. The problem of angle variations can be mitigated by the selection of an appropriate reference bus. A method to solve the second problem, of variation in load admittances, has been proposed in this dissertation and given the

  11. Optimum electrode configuration selection for electrical resistance change based damage detection in composites using an effective independence measure

    Science.gov (United States)

    Escalona, Luis; Díaz-Montiel, Paulina; Venkataraman, Satchi

    2016-04-01

    Laminated carbon fiber reinforced polymer (CFRP) composite materials are increasingly used in aerospace structures due to their superior mechanical properties and reduced weight. Assessing the health and integrity of these structures requires non-destructive evaluation (NDE) techniques to detect and measure interlaminar delamination and intralaminar matrix cracking damage. The electrical resistance change (ERC) based NDE technique uses the inherent changes in conductive properties of the composite to characterize internal damage. Several works that have explored the ERC technique have been limited to thin cross-ply laminates with simple linear or circular electrode arrangements. This paper investigates a method of optimum selection of electrode configurations for delamination detection in thick cross-ply laminates using ERC. Inverse identification of damage requires numerical optimization of the measured response with a model predicted response. Here, the electrical voltage field in the CFRP composite laminate is calculated using finite element analysis (FEA) models for different specified delamination size and locations, and location of ground and current electrodes. Reducing the number of sensor locations and measurements is needed to reduce hardware requirements, and computational effort needed for inverse identification. This paper explores the use of effective independence (EI) measure originally proposed for sensor location optimization in experimental vibration modal analysis. The EI measure is used for selecting the minimum set of resistance measurements among all possible combinations of selecting a pair of electrodes among the n electrodes. To enable use of EI to ERC required, it is proposed in this research a singular value decomposition SVD to obtain a spectral representation of the resistance measurements in the laminate. The effectiveness of EI measure in eliminating redundant electrode pairs is demonstrated by performing inverse identification of

  12. A Robust Electrode Configuration for Bioimpedance Measurement of Respiration

    Directory of Open Access Journals (Sweden)

    Hong-bin Wang

    2014-01-01

    Full Text Available Electrode configuration is an important issue in the continuous measurement of respiration using impedance pneumography (IP. The robust configuration is usually confirmed by comparing the amplitude of the IP signals acquired with different electrode configurations, while the relative change in waveform and the effects of body posture and respiratory pattern are ignored. In this study, the IP signals and respiratory volume are simultaneously acquired from 8 healthy subjects in supine, left lying, right lying and prone postures, and the subjects are asked to perform four respiratory patterns including free breathing, thoracic breathing, abdominal breathing and apnea. The IP signals are acquired with four different chest electrode configurations, and the volume are measured using pneumotachograph (PNT. Differences in correlation and absolute deviation between the IP-derived and PNT-derived respiratory volume are assessed. The influences of noise, respiratory pattern and body posture on the IP signals of different configurations have significant difference (p < 0.05. The robust electrode configuration is found on the axillary midline, which is suitable for long term respiration monitoring.

  13. A robust electrode configuration for bioimpedance measurement of respiration.

    Science.gov (United States)

    Wang, Hong-Bin; Yen, Chen-Wen; Liang, Jing-Tao; Wang, Qian; Liu, Guan-Zheng; Song, Rong

    2014-01-01

    Electrode configuration is an important issue in the continuous measurement of respiration using impedance pneumography (IP). The robust configuration is usually confirmed by comparing the amplitude of the IP signals acquired with different electrode configurations, while the relative change in waveform and the effects of body posture and respiratory pattern are ignored. In this study, the IP signals and respiratory volume are simultaneously acquired from 8 healthy subjects in supine, left lying, right lying and prone postures, and the subjects are asked to perform four respiratory patterns including free breathing, thoracic breathing, abdominal breathing and apnea. The IP signals are acquired with four different chest electrode configurations, and the volume are measured using pneumotachograph (PNT). Differences in correlation and absolute deviation between the IP-derived and PNT-derived respiratory volume are assessed. The influences of noise, respiratory pattern and body posture on the IP signals of different configurations have significant difference (p < 0.05). The robust electrode configuration is found on the axillary midline, which is suitable for long term respiration monitoring.

  14. Adaptive Voltage Stability Protection Based on Load Identification Using Phasor Measurement Units

    DEFF Research Database (Denmark)

    Liu, Leo; Bak, Claus Leth; Chen, Zhe

    2011-01-01

    collapse. In this paper, the online load identification using measurement-based approach based on Phasor Measurement Units (PMU) was proposed to evaluate the proximity to voltage instability in order to prevent voltage collapse. In the scenarios of disturbances, the proximity to voltage collapse...

  15. High-Q AlN Contour Mode Resonators with Unattached, Voltage-Actuated Electrodes

    Science.gov (United States)

    Schneider, Robert Anthony

    High-Q narrowband filters at ultra-high frequencies hold promise for reducing noise and suppressing interferers in wireless transceivers, yet research efforts confront a daunting challenge. So far, no existing resonator technology can provide the simultaneous high-Q, high electromechanical coupling ( k2eff), frequency tunability, low motional resistance (Rx), stopband rejection, self-switchability, frequency accuracy, and power handling desired to select individual channels or small portions of a band over a wide RF range. Indeed, each technology provides only a subset of the desired properties. Recently introduced "capacitive-piezoelectric" resonators, i.e., piezoelectric resonators with non-contacting transduction electrodes, known for achieving very good Q's, have recently emerged (in the early 2010's) as a contender among existing technologies to address the needs of RF narrowband selection. Several reports of such devices, made from aluminum nitride (AlN), have demonstrated improved Q's over attached electrode counterparts at frequencies up to 1.2 GHz, albeit with reduced transduction efficiency due to the added capacitive gaps. Fabrication challenges, while still allowing for a glimpse of the promise of this technology, have, until now, hindered attempts at more complex devices than just simple resonators with improved Q's. This thesis project demonstrates several key improvements to capacitive-piezo technology, which, taken together, further bolster its case for deployment for frequency control applications. (Abstract shortened by ProQuest.).

  16. Investigation of low-voltage pulse parameters on electroporation and electrical lysis using a microfluidic device with interdigitated electrodes.

    Science.gov (United States)

    Morshed, Bashir I; Shams, Maitham; Mussivand, Tofy

    2014-03-01

    Electroporation (EP) of biological cells leads to the exchange of materials through the permeabilized cell membrane, while electrical lysis (EL) irreversibly disrupts the cell membrane. We report a microfluidic device to study these two phenomena with low-voltage excitation for lab-on-a-chip (LOC) applications. For systematic study of EP, we have employed a quantification metric: flow Index (FI) of EP. Simulation and experimental results with the microfluidic device containing interdigitated, coplanar, integrated electrodes to electroporate, and rapidly lyse biological cells are presented. H&E stained human buccal cells were subjected to various pulse magnitudes, pulsewidths, and number of pulses. Simulations show that an electric field of 25 kV/cm with a 20 V applied potential produced 1.3 (°)C temperature rise for a 5 s of excitation. For a 20 V pulse-excitation with pulse-widths between 0.5 to 5 s, EL was observed, whereas for lower excitations, only EP was observed. FI of EP is found to be a direct function of pulse magnitudes, pulsewidths, and numbers of pulses. To release DNA from nucleus, excitation-pulses of 5 s were required. Quantification of EP would be useful for systematic study of EP toward optimization with various excitation pulses, while low-voltage requirement and high yield of EP and EL are critical to develop LOC for drug delivery and cell-sample preparation, respectively.

  17. A flexible microneedle array as low-voltage electroporation electrodes for in vivo DNA and siRNA delivery.

    Science.gov (United States)

    Wei, Zewen; Zheng, Shuquan; Wang, Renxin; Bu, Xiangli; Ma, Huailei; Wu, Yidi; Zhu, Ling; Hu, Zhiyuan; Liang, Zicai; Li, Zhihong

    2014-10-21

    In vivo electroporation is an appealing method to deliver nucleic acid into living tissues, but the clinical application of such a method was limited due to severe tissue damage and poor coverage of the tissue surface. Here we present the validation of a novel flexible microneedle array electrode (MNAE) chip, in which the microneedle array and the flexible substrate are integrated together to simultaneously facilitate low-voltage electroporation and accomplish good coverage of the tissue surface. The efficient delivery of both DNA and siRNA was demonstrated on mice. Upon penetrating the high-resistance stratum corneum, the electroporation voltage was reduced to about 35 V, which was generally recognized safe for humans. Also, a pathological analysis of the microneedle-electroporated tissues was carried out to thoroughly assess the skin damage, which is an important consideration in pre-clinical studies of electroporation devices. This MNAE constitutes a novel way of in vivo delivery of siRNA and DNA to certain tissues or organs with satisfactory efficiency and good adaptation to the tissue surface profile as well as minimum tissue damage, thus avoiding the disadvantages of existing electroporation methods.

  18. Low-voltage FIB/SEM Tomography for 3D Microstructure Evolution of LiFePO4/C Electrode

    DEFF Research Database (Denmark)

    Scipioni, Roberto; Jørgensen, Peter Stanley; Ngo, Duc-The

    2015-01-01

    This work presents an investigation of the degradation mechanisms that occur in LiFePO4/C battery electrodes during charge/discharge cycling. Impedance spectra were measured on a fresh electrode and an electrode aged by cycling. The spectra were modeled with an equivalent circuit which indicates...

  19. A microbial fuel cell with the three-dimensional electrode applied an external voltage for synthesis of hydrogen peroxide from organic matter

    Science.gov (United States)

    Chen, Jia-yi; Zhao, Lin; Li, Nan; Liu, Hang

    2015-08-01

    The study experimentally investigates the changing performance of three-dimensional electrode H2O2-producting MFCs coupled with simultaneous wastewater treatment at various external cell voltages from 0.1 V to 0.8 V, in order to explore the optimal applied voltage and its reasons. The graphite particle electrodes made of graphite powders with polytetrafluoroethene (PTFE) as the binder are used as three-dimensional cathode. The results indicate that applied voltage is demonstrated to increase the productive rate and output of H2O2 and the efficiency of acetate degradation. Besides, a relatively high current density caused by a high applied voltage has a positive impact on anode performance in terms of organic degradation and coulombic efficiency. In addition, a relatively high voltage leads to the reduction of H2O2 and the evolution of H2. Considering H2O2 concentration, anodic COD removal and current efficiencies of MFCs at various voltages, the optimal voltage is chosen to be 0.4 V, achieving the H2O2 generation of 705.6 mg L-1 at a rate of 2.12 kg m-3 day-1 and 76% COD removal in 8 h, with energy input of 0.659 kWh per kg H2O2. Coulombic efficiency, faradic efficiency and COD conversion efficiency are 92%, 96%, and 88% respectively.

  20. Modelling of the measured longitudinal piezoelectric coefficient of single ceramic fibres with annular electrodes

    Science.gov (United States)

    Pientschke, Christoph; Steinhausen, Ralf; Kern, Sabine; Beige, Horst

    2011-05-01

    A method for the measurement of the longitudinal piezoelectric coefficient d33 of single ceramic fibres with diameters 100-500 µm was recently developed. The voltage was applied using annular electrodes and the resulting displacement was measured by a capacitive method. In this paper, a number of calculations regarding the field distribution and the resulting piezoelectric displacement are presented for a typical lead zirconate titanate (PZT) ceramic. Provided that the fibres are ideally poled in the longitudinal direction, they can be modelled using the finite element method taking into account linear constitutive equations. The deviation of the measured and the actual d33 was modelled for a broad range of heights and diameters of the fibres and different electrode dimensions. The electric field distribution was analysed for typical examples and the influence of the mechanical stress on the measured d33 was studied. For sufficiently long and thin fibres the field distribution of the electric field is quite uniform and the d33 can be measured with high accuracy. Moreover, it was shown that for such fibres the measured piezoelectric coefficient d33 is determined by no other material parameter of the ceramics. The found trends of preferable geometries for the measurement can apparently be transferred to other piezoceramics.

  1. Diffusion voltage in polymer light emitting diodes measured with electric field induced second harmonic generation

    Science.gov (United States)

    Kristensen, P. K.; Rafaelsen, J.; Pedersen, T. G.; Pedersen, K.

    2005-12-01

    We apply electric field induced second harmonic (EFISH) to polymer light emitting diodes (PLEDs) and demonstrate the ability to determine the diffusion voltage in PLED devices. The EFISH signal is proportional to the square of the effective field, which is the sum of the diffusion voltage and the applied voltage. By minimizing the EFISH-signal as a function of the applied voltage, the diffusion voltage is determined by measuring the applied voltage that cancels out the diffusion voltage. The PLEDs are fabricated with indium tin oxide (ITO) as the hole injecting contact and two different electron injecting contacts, namely aluminum and calcium. The diffusion voltage originates from the rearranged charges caused by the difference in Fermi levels in the materials in the PLEDs. Different contacts will thus cause different diffusion voltages. We demonstrate here that the EFISH signal is proportional to the square of the effective field in both reverse and forward bias, and discuss the dependence on contact materials.

  2. Monitoring and intelligent control of electrode wear based on a measured electrode displacement curve in resistance spot welding

    Science.gov (United States)

    Zhang, Y. S.; Wang, H.; Chen, G. L.; Zhang, X. Q.

    2007-03-01

    Advanced high strength steels are being increasingly used in the automotive industry to reduce weight and improve fuel economy. However, due to increased physical properties and chemistry of high strength steels, it is difficult to directly substitute these materials into production processes currently designed for mild steels. New process parameters and process-related issues must be developed and understood for high strength steels. Among all issues, endurance of the electrode cap is the most important. In this paper, electrode wear characteristics of hot-dipped galvanized dual-phase (DP600) steels and the effect on weld quality are firstly analysed. An electrode displacement curve which can monitor electrode wear was measured by a developing experimental system using a servo gun. A neuro-fuzzy inference system based on the electrode displacement curve is developed for minimizing the effect of a worn electrode on weld quality by adaptively adjusting input variables based on the measured electrode displacement curve when electrode wear occurs. A modified current curve is implemented to reduce the effects of electrode wear on weld quality using a developed neuro-fuzzy system.

  3. System for improving measurement accuracy of transducer by measuring transducer temperature and resistance change using thermoelectric voltages

    Science.gov (United States)

    Anderson, Karl F. (Inventor); Parker, Allen R., Jr. (Inventor)

    1993-01-01

    A constant current loop measuring system measures a property including the temperature of a sensor responsive to an external condition being measured. The measuring system includes thermocouple conductors connected to the sensor, sensing first and second induced voltages responsive to the external condition. In addition, the measuring system includes a current generator and reverser generating a constant current, and supplying the constant current to the thermocouple conductors in forward and reverse directions generating first and second measured voltages, and a determining unit receiving the first and second measured voltages from the current generator and reverser, and determining the temperature of the sensor responsive to the first and second measured voltages.

  4. Adaptive Voltage Stability Protection Based on Load Identification Using Phasor Measurement Units

    DEFF Research Database (Denmark)

    Liu, Leo; Bak, Claus Leth; Chen, Zhe

    2011-01-01

    collapse. In this paper, the online load identification using measurement-based approach based on Phasor Measurement Units (PMU) was proposed to evaluate the proximity to voltage instability in order to prevent voltage collapse. In the scenarios of disturbances, the proximity to voltage collapse...... with respect to load characteristics was evaluated. Based on different load characteristics, different control and protection schemes were implemented, i.e. shunt capacitor connection, on-load tap changer blocking and load shedding. The results showed that load-based adaptive voltage control and protection...... scheme based on PMUs is promising, as it prevented the voltage collapse and minimized the load shedding area....

  5. First high-voltage measurements using Ca{sup +} ions at the ALIVE experiment

    Energy Technology Data Exchange (ETDEWEB)

    König, K., E-mail: kkoenig@ikp.tu-darmstadt.de [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Geppert, Ch. [Universität Mainz, Institut für Kernchemie (Germany); Krämer, J.; Maaß, B. [Technische Universität Darmstadt, Institut für Kernphysik (Germany); Otten, E. W. [Universität Mainz, Institut für Physik (Germany); Ratajczyk, T.; Nörtershäuser, W. [Technische Universität Darmstadt, Institut für Kernphysik (Germany)

    2017-11-15

    Many physics experiments depend on accurate high-voltage measurements to determine for example the exact retardation potential of an electron spectrometer as in the KATRIN experiment or the acceleration voltage of the ions at ISOL facilities. Until now only precision high-voltage dividers can be used to measure voltages up to 65 kV with an accuracy of 1 ppm. However, these dividers need frequent calibration and cross-checking and the direct traceability is not given. In this article we will describe the status of an experiment which aims to measure high voltages using collinear laser spectroscopy and which has the potential to provide a high-voltage standard and hence, a calibration source for precision high-voltage dividers on the 1 ppm level.

  6. A comparative study for detection and measurement of voltage disturbance in online condition

    Directory of Open Access Journals (Sweden)

    Vijay Gajanan Neve

    2015-05-01

    Full Text Available Voltage disturbance is the most important power quality problem faced by many industrial customers. It includes voltage sag, swell, spikes and harmonics. Real time detection of these voltage disturbances posed various problems. This paper compares the various methods of detection of voltage sag and swells in real time on the basis of detection time, magnitude, effect of windowing and effect of sampling frequencies. The RMS, Peak, Fourier transform and Missing Voltage algorithm are introduced and discussed in them for real time implementation. Comparative analysis reveals that quantification of voltage sag and swell is possible using these measurements. The main focus is given on to these points and all the voltage sag and swell detection technique tested online with the help of advantech card data acquisition. The voltage sag and swell events are generated by using practical experimentation in laboratory.

  7. Sputtering TiO2 on LiCoO2 composite electrodes as a simple and effective coating to enhance high-voltage cathode performance

    Science.gov (United States)

    Zhou, Aijun; Lu, Yanting; Wang, Qingji; Xu, Jin; Wang, Weihang; Dai, Xinyi; Li, Jingze

    2017-04-01

    Surface coating is a key strategy in lithium-ion battery technologies to achieve a high and stable battery performance. Increasing the operation voltage is a direct way to increase the energy density of the battery. In this work, TiO2 is directly sputtered on as-fabricated LiCoO2 composite electrodes, enabling a controllable oxide coating on the topmost of the electrode. With an optimum coating, the discharge capacity is able to reach 160 mAh g-1 (86.5% retention) after 100 cycles within 3.0-4.5 V at 1 C, which is increased by 40% compared to that of the bare electrode. The high-voltage rate capability of LiCoO2 is also remarkably enhanced after TiO2-coating as reflected by the much larger capacity at 10 C (109 vs. 74 mAh g-1). The artificially introduced oxide coating is believed to make the LiCoO2 electrode more resistant to interfacial side reactions at high voltage and thus minimizes the irreversible loss of the active material upon long cycling. The TiO2 coating layer is also possible to partially react with the decomposition product of electrolyte (e.g. HF) and form a more stable and conductive interphase containing TiFx, which is responsible for the improvement of the rate capability.

  8. Modeling of the Partial Discharge Process in a Liquid Dielectric: Effect of Applied Voltage, Gap Distance, and Electrode Type

    Directory of Open Access Journals (Sweden)

    Tao Yuan

    2013-02-01

    Full Text Available The partial discharge (PD process in liquid dielectrics is influenced by several factors. Although the PD current contains the information representing the discharge process during the PD event, it is difficult to determine the detailed dynamics of what is happening in the bulk of the liquid. In this paper, a microscopic model describing the dynamics of the charge carriers is implemented. The model consists of drift-diffusion equations of electrons, positive and negative ions coupled with Poisson’s equation. The stochastic feature of PD events is included in the equation. First the model is validated through comparison between the calculated PD current and experimental data. Then experiments are conducted to study the effects of the amplitude of the applied voltage, gap distance and electrode type on the PD process. The PD currents under each condition are recorded. Simulations based on the model have been conducted to analyze the dynamics of the PD events under each condition, and thus explain the mechanism of how these factors influence the PD events. The space charge generated in the PD process is revealed as the main reason affecting the microscopic process of the PD events.

  9. Measurement of Mechatronic Property of Biological Gel with Micro-Vibrating Electrode at Ultrasonic Frequency

    Directory of Open Access Journals (Sweden)

    Shigehiro Hashimoto

    2008-10-01

    Full Text Available A measurement system has been designed with a micro-vibrating electrode at ultrasonic frequency to measure local impedance of biological gel in vitro. The designed system consists of two electrodes, where one of the electrodes vibrates with a piezoelectric actuator. The component of variation at impedance between two electrodes with vibration of one electrode is analyzed at the corresponding spectrum. The manufactured system was applied to measure impedance of a physiological saline solution, a potassium chloride solution, a dextran aqueous solution, and an egg. The experimental results show that the designed system is effective to measure local mechatronic property of biological gel.

  10. The use of virtual ground to control transmembrane voltages and measure bilayer currents in serial arrays of droplet interface bilayers

    Science.gov (United States)

    Sarles, Stephen A.

    2013-09-01

    The droplet interface bilayer (DIB) is a simple technique for constructing a stable lipid bilayer at the interface of two lipid-encased water droplets submerged in oil. Networks of DIBs formed by connecting more than two droplets constitute a new form of modular biomolecular smart material, where the transduction properties of a single lipid bilayer can affect the actions performed at other interface bilayers in the network via diffusion through the aqueous environments of shared droplet connections. The passive electrical properties of a lipid bilayer and the arrangement of droplets that determine the paths for transport in the network require specific electrical control to stimulate and interrogate each bilayer. Here, we explore the use of virtual ground for electrodes inserted into specific droplets in the network and employ a multichannel patch clamp amplifier to characterize bilayer formation and ion-channel activity in a serial DIB array. Analysis of serial connections of DIBs is discussed to understand how assigning electrode connections to the measurement device can be used to measure activity across all lipid membranes within a network. Serial arrays of DIBs are assembled using the regulated attachment method within a multi-compartment flexible substrate, and wire-type electrodes inserted into each droplet compartment of the substrate enable the application of voltage and measurement of current in each droplet in the array.

  11. Measurements for validation of high voltage underground cable modelling

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Gudmundsdottir, Unnur Stella; Wiechowski, Wojciech Tomasz

    2009-01-01

    This paper discusses studies concerning cable modelling for long high voltage AC cable lines. In investigating the possibilities of using long cables instead of overhead lines, the simulation results must be trustworthy. Therefore a model validation is of great importance. This paper describes...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-14

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

  13. Electrode-selective deposition/etching processes using an SiF4/H2/Ar plasma chemistry excited by sawtooth tailored voltage waveforms

    Science.gov (United States)

    Wang, J. K.; Johnson, E. V.

    2017-01-01

    We report on the electrode-selective deposition and etching of hydrogenated silicon thin films using a plasma enhanced chemical vapour deposition process excited by sawtooth-shaped tailored voltage waveforms (TVWs). The slope asymmetry of such waveforms leads to a different rate of sheath expansion and contraction at each electrode, and therefore different electron power absorption near each electrode. This effect was employed with an SiF4/H2/Ar plasma chemistry, as the surface processes that result from this gas mixture depend strongly on the local balance between multiple precursors. For a specific gas flow ratio, a deposition rate of 0.82 Å s-1 on one electrode and an etching rate of 1.2 Å s-1 on the other were achieved. Moreover, this deposition/etching balance is controlled by the H2 flow rate, which limits the deposition rate at low flows. When the H2 injection is sufficiently high, the processes are then limited by the dissociation of SiF4, and the relative rate of the surface processes on the two electrodes are reversed, i.e. a higher net deposition rate is observed on the electrode where the fast sheath contraction occurs due to the electronegative character of the plasma.

  14. Measuring Vitamin C Content of Commercial Orange Juice Using a Pencil Lead Electrode

    Science.gov (United States)

    King, David; Friend, Jeffrey; Kariuki, James

    2010-01-01

    A pencil lead successfully served as an electrode for the determination of ascorbic acid in commercial orange juice. Cyclic voltammetry was used as an electrochemical probe to measure the current produced from the oxidation of ascorbic acid with a variety of electrodes. The data demonstrate that the less expensive pencil lead electrode gives…

  15. Measuring Vitamin C Content of Commercial Orange Juice Using a Pencil Lead Electrode

    Science.gov (United States)

    King, David; Friend, Jeffrey; Kariuki, James

    2010-01-01

    A pencil lead successfully served as an electrode for the determination of ascorbic acid in commercial orange juice. Cyclic voltammetry was used as an electrochemical probe to measure the current produced from the oxidation of ascorbic acid with a variety of electrodes. The data demonstrate that the less expensive pencil lead electrode gives…

  16. The ECG measurement in the bathtub using the insulated electrodes.

    Science.gov (United States)

    Lim, Yong Kyu; Kim, Ko Keun; Park, Kwang Suk

    2004-01-01

    The ECG recording in the bathtub was studied using insulated electrode. Prior studies of the ECG recording in the bathtub used conductive electrodes having some problems such as the possibility of the electric shock and sensitivity to contamination of the electrode surfaces. The insulated electrodes were made of copper plate coated with PET film. The electrodes were attached on bathtub at both sides of the chest. High-input-impedance amplifier was designed to amplify ECG signal sensed by insulated electrodes of high impedance. The recorded signals in this study were noisier than those recorded with conventional conductive electrodes. But the R peaks in the recorded signals were large enough to be auto-detected. Further study will improve SNR by reducing of power line noise and common-mode noise.

  17. Schottky bipolar I-MOS: An I-MOS with Schottky electrodes and an open-base BJT configuration for reduced operating voltage

    Science.gov (United States)

    Kannan, N.; Kumar, M. Jagadesh

    2017-04-01

    In this paper, we have proposed a novel impact ionization MOS (I-MOS) structure, called the Schottky bipolar I-MOS, with Schottky source and drain electrodes and utilizing the open-base bipolar junction transistor (BJT) configuration for achieving reduction in the operating voltage of the I-MOS transistor. We report, using 2-D simulations, a low operating voltage (∼1.1 V) and a low subthreshold swing (∼3.6 mV/Decade). For the corresponding p-i-n I-MOS, the operating voltage is ∼5.5 V. The operating voltage of the Schottky bipolar I-MOS is the lowest reported operating voltage for silicon based I-MOS transistors. The nearly 80% reduction in the operating voltage of the Schottky bipolar I-MOS makes it suitable for applications requiring low operating voltages. The Schottky bipolar I-MOS is also expected to have an improved reliability over the p-i-n I-MOS since high energy carriers, induced by impact ionization near the drain, do not have to pass under the gate region in the channel. The use of Schottky contacts instead of heavily doped source and drain regions and the low channel doping level reduces the required thermal budget for device fabrication. The low operating voltage, low subthreshold swing and possibly improved reliability of the Schottky bipolar I-MOS, makes it a potential solution for applications where steep subthreshold slope transistors are being explored as alternative to the conventional MOS transistor.

  18. Air Flow Measurements During Medium-Voltage Load Current Interruptions

    OpenAIRE

    Aanensen, Nina Sasaki; Runde, Magne

    2015-01-01

    Air has been considered a good alternative to SF6 as arc quenching medium for load break switchgear at medium voltage ratings. In this work, the air flow characteristics and influence from the electric arc have been studied for typical currents and over-pressures. The cooling air velocity is typically in the range 150 - 200 m/s and thus well below supersonic speed. The arc and the surrounding hot air severely affect the air flow pattern by causing clogging in the contact and nozzle region.

  19. Time based measurement of the impedance of the skin-electrode interface for dry electrode ECG recording.

    Science.gov (United States)

    Dozio, Roberta; Baba, Adeshina; Assambo, Cedric; Burke, Martin J

    2007-01-01

    This paper reports the measurement of the properties of dry or pasteless conductive electrodes to be used for long-term recording of the human electrocardiogram (ECG). Knowledge of these properties is essential for the correct design of the input stage of associated recording amplifiers. Measurements were made on three commercially available conductive carbon based electrodes at pressures of 5 mmHg and 20 mmHg, located on the lower abdomen of the body on three subjects having different skin types. Parameter values were fitted to a two-time-constant based model of the electrode using data measured over a period of 10s. Values of resistance, ranging from 40kOmega to 1590kOmega and of capacitance ranging from 0.05 microF to 38 microF were obtained for the components, while the values of the time-constants varied from 0.07 s to 3.9s.

  20. Stark effect and photoconductivity of fullerene C70 measured on samples with a submicron electrode grating and sandwich geometry

    Science.gov (United States)

    Blinov, L. M.; Lazarev, V. V.; Yudin, S. G.

    2016-09-01

    The electroabsorption (Stark effect) and photoconductivity of polycrystalline fullerene C70 in thinfilm samples with radically different geometries (sample 1 with interdigital Cr electrodes and sandwichlike sample 2 with SnO2 and Al electrodes) have been investigated. It is noteworthy that sample 1 is a submicron grating with 0.88-µm gaps between electrodes. When measuring electroabsorption and photoconductivity, the external voltage does not exceed 4 V. It was assumed that the small gap size may significantly affect the polycrystalline film morphology and surface effects and, as a consequence, the electroabsorption and charge carrier mobility. However, the results of the Stark effect measurements on samples with different geometries differ by only 25%, whereas the spectral photoconductivity values differ by factors of 1-2.5. The increase in photoconductivity may be related to the decrease in the carrier mobility in the sandwich sample or the increase in the number of carriers under the influence of atmospheric oxygen in the surface layer of C70 sample with interdigital electrodes.

  1. Measurement and analysis of postsynaptic potentials using a novel voltage-deconvolution method.

    Science.gov (United States)

    Richardson, Magnus J E; Silberberg, Gilad

    2008-02-01

    Accurate measurement of postsynaptic potential amplitudes is a central requirement for the quantification of synaptic strength, dynamics of short-term and long-term plasticity, and vesicle-release statistics. However, the intracellular voltage is a filtered version of the underlying synaptic signal and so a method of accounting for the distortion caused by overlapping postsynaptic potentials must be used. Here a voltage-deconvolution technique is demonstrated that defilters the entire voltage trace to reveal an underlying signal of well-separated synaptic events. These isolated events can be cropped out and reconvolved to yield a set of isolated postsynaptic potentials from which voltage amplitudes may be measured directly-greatly simplifying this common task. The method also has the significant advantage of providing a higher temporal resolution of the dynamics of the underlying synaptic signal. The versatility of the method is demonstrated by a variety of experimental examples, including excitatory and inhibitory connections to neurons with passive membranes and those with activated voltage-gated currents. The deconvolved current-clamp voltage has many features in common with voltage-clamp current measurements. These similarities are analyzed using cable theory and a multicompartment cell reconstruction, as well as direct comparison to voltage-clamp experiments.

  2. Effect of Voltage Measurement on the Quantitative Identification of Transverse Cracks by Electrical Measurements

    KAUST Repository

    Selvakumaran, Lakshmi

    2016-03-24

    Electrical tomography can be used as a structural health monitoring technique to identify different damage mechanisms in composite laminates. Previous work has established the link between transverse cracking density and mesoscale conductivity of the ply. Through the mesoscale relationship, the conductivity obtained from electrical tomography can be used as a measure of the transverse cracking density. Interpretation of this measure will be accurate provided the assumptions made during homogenization are valid. One main assumption of mesoscale homogenization is that the electric field is in the plane. Here, we test the validity of this assumption for laminates with varying anisotropy ratios and for different distances between the cracked ply and surface that is instrumented with electrodes. We also show the equivalence in electrical response between measurements from cracked laminates and their equivalent mesoscale counterparts. Finally, we propose some general guidelines on the measurement strategy for maximizing the accuracy of transverse cracks identification.

  3. Diffusion voltage in polymer light emitting diodes measured with electric field induced second harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, P.K.; Rafaelsen, J.; Pedersen, T.G.; Pedersen, K. [Department of Physics and Nanotechnology, Aalborg University, Pontoppidanstraede 103, 9220 Aalborg East (Denmark)

    2005-12-01

    We apply electric field induced second harmonic (EFISH) to polymer light emitting diodes (PLEDs) and demonstrate the ability to determine the diffusion voltage in PLED devices. The EFISH signal is proportional to the square of the effective field, which is the sum of the diffusion voltage and the applied voltage. By minimizing the EFISH-signal as a function of the applied voltage, the diffusion voltage is determined by measuring the applied voltage that cancels out the diffusion voltage. The PLEDs are fabricated with indium tin oxide (ITO) as the hole injecting contact and two different electron injecting contacts, namely aluminum and calcium. The diffusion voltage originates from the rearranged charges caused by the difference in Fermi levels in the materials in the PLEDs. Different contacts will thus cause different diffusion voltages. We demonstrate here that the EFISH signal is proportional to the square of the effective field in both reverse and forward bias, and discuss the dependence on contact materials. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Classification of methods for measuring current-voltage characteristics of semiconductor devices

    Directory of Open Access Journals (Sweden)

    Iermolenko Ia. O.

    2014-06-01

    Full Text Available It is shown that computer systems for measuring current-voltage characteristics are very important for semiconductor devices production. The main criteria of efficiency of such systems are defined. It is shown that efficiency of such systems significantly depends on the methods for measuring current-voltage characteristics of semiconductor devices. The aim of this work is to analyze existing methods for measuring current-voltage characteristics of semiconductor devices and to create the classification of these methods in order to specify the most effective solutions in terms of defined criteria. To achieve this aim, the most common classifications of methods for measuring current-voltage characteristics of semiconductor devices and their main disadvantages are considered. Automated and manual, continuous, pulse, mixed, isothermal and isodynamic methods for measuring current-voltage characteristics are analyzed. As a result of the analysis and generalization of existing methods the next classification criteria are defined: the level of automation, the form of measurement signals, the condition of semiconductor device during the measurements, and the use of mathematical processing of the measurement results. With the use of these criteria the classification scheme of methods for measuring current-voltage characteristics of semiconductor devices is composed and the most effective methods are specified.

  5. A fault-tolerant voltage measurement method for series connected battery packs

    Science.gov (United States)

    Xia, Bing; Mi, Chris

    2016-03-01

    This paper proposes a fault-tolerant voltage measurement method for battery management systems. Instead of measuring the voltage of individual cells, the proposed method measures the voltage sum of multiple battery cells without additional voltage sensors. A matrix interpretation is developed to demonstrate the viability of the proposed sensor topology to distinguish between sensor faults and cell faults. A methodology is introduced to isolate sensor and cell faults by locating abnormal signals. A measurement electronic circuit is proposed to implement the design concept. Simulation and experiment results support the mathematical analysis and validate the feasibility and robustness of the proposed method. In addition, the measurement problem is generalized and the condition for valid sensor topology is discovered. The tuning of design parameters are analyzed based on fault detection reliability and noise levels.

  6. Novel dry polymer foam electrodes for long-term EEG measurement.

    Science.gov (United States)

    Lin, Chin-Teng; Liao, Lun-De; Liu, Yu-Hang; Wang, I-Jan; Lin, Bor-Shyh; Chang, Jyh-Yeong

    2011-05-01

    A novel dry foam-based electrode for long-term EEG measurement was proposed in this study. In general, the conventional wet electrodes are most frequently used for EEG measurement. However, they require skin preparation and conduction gels to reduce the skin-electrode contact impedance. The aforementioned procedures when wet electrodes were used usually make trouble to users easily. In order to overcome the aforesaid issues, a novel dry foam electrode, fabricated by electrically conductive polymer foam covered by a conductive fabric, was proposed. By using conductive fabric, which provides partly polarizable electric characteristic, our dry foam electrode exhibits both polarization and conductivity, and can be used to measure biopotentials without skin preparation and conduction gel. In addition, the foam substrate of our dry electrode allows a high geometric conformity between the electrode and irregular scalp surface to maintain low skin-electrode interface impedance, even under motion. The experimental results presented that the dry foam electrode performs better for long-term EEG measurement, and is practicable for daily life applications.

  7. Concurrent two-phase downflow measurement with an induced voltage electro-magnetic flowmeter

    OpenAIRE

    Opara, Uroš; Bajsič, Ivan

    2015-01-01

    With a set of polynomial approximations a possibility is shown of the use of an induced voltage electromagnetic flowmeter in the area of measuring cocurrent two-phase downflow in tubes. The principle of the meter operation remains hereby unchanged

  8. Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

    Science.gov (United States)

    West, R. M.; Semancik, S.

    2016-11-01

    Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

  9. Selection of the Optimum Electrospray Voltage for Gradient Elution LC-MS Measurements

    Science.gov (United States)

    Marginean, Ioan; Kelly, Ryan T.; Moore, Ronald J.; Prior, David C.; LaMarche, Brian L.; Tang, Keqi; Smith, Richard D.

    2009-01-01

    Changes in liquid composition during gradient elution liquid chromatography (LC) coupled to mass spectrometry (MS) analyses affect the electrospray operation. To establish methodologies for judicious selection of the electrospray voltage, we monitored in real-time the effect of the LC gradient on the spray current. The optimum range of the electrospray voltage decreased as the concentration of organic solvent in the eluent increased during reversed-phase LC analyses. These results provided the means to rationally select the voltage so as to ensure effective electrospray operation throughout gradient-elution LC separations. For analyses in which the electrospray was operated at constant voltage, a small run-to-run variation in the spray current was observed, indicating a changing electric field due to fouling or degradation of the emitter. Algorithms using feedback from spray current measurements to maintain the electrospray voltage within the optimum operating range throughout gradient elution LC-MS were evaluated. The electrospray operation with voltage regulation and at a constant, judiciously selected voltage during gradient elution LC-MS measurements produced data with similar reproducibility. SYNOPSIS Electrospray current measurements during gradient elution liquid chromatography analyses provide reliable feedback for monitoring, understanding, and improving performance. PMID:19196520

  10. Measurement of effective piezoelectric coefficients of PZT thin films for energy harvesting application with interdigitated electrodes.

    Science.gov (United States)

    Chidambaram, Nachiappan; Mazzalai, Andrea; Muralt, Paul

    2012-08-01

    Interdigitated electrode (IDE) systems with lead zirconate titanate (PZT) thin films play an increasingly important role for two reasons: first, such a configuration generates higher voltages than parallel plate capacitor-type electrode (PPE) structures, and second, the application of an electric field leads to a compressive stress component in addition to the overall stress state, unlike a PPE structure, which results in tensile stress component. Because ceramics tend to crack at relatively moderate tensile stresses, this means that IDEs have a lower risk of cracking than PPEs. For these reasons, IDE systems are ideal for energy harvesting of vibration energy, and for actuators. Systematic investigations of PZT films with IDE systems have not yet been undertaken. In this work, we present results on the evaluation of the in-plane piezoelectric coefficients with IDE systems. Additionally, we also propose a simple and measurable figure of merit (FOM) to analyze and evaluate the relevant piezoelectric parameter for harvesting efficiency without the need to fabricate the energy harvesting device. Idealized effective coefficients e(IDE) and h(IDE) are derived, showing its composite nature with about one-third contribution of the transverse effect, and about two-thirds contribution of the longitudinal effect in the case of a PZT film deposited on a (100)-oriented silicon wafer with the in-plane electric field along one of the Si directions. Randomly oriented 1-μm-thick PZT 53/47 film deposited by a sol-gel technique, was evaluated and yielded an effective coefficient e(IDE) of 15 C·m(-2). Our FOM is the product between effective e and h coefficient representing twice the electrical energy density stored in the piezoelectric film per unit strain deformation (both for IDE and PPE systems). Assuming homogeneous fields between the fingers, and neglecting the contribution from below the electrode fingers, the FOM for IDE structures with larger electrode gap is derived to be

  11. Crystallographic origin of cycle decay of the high-voltage LiNi0.5Mn1.5O4 spinel lithium-ion battery electrode.

    Science.gov (United States)

    Pang, Wei Kong; Lu, Cheng-Zhang; Liu, Chia-Erh; Peterson, Vanessa K; Lin, Hsiu-Fen; Liao, Shih-Chieh; Chen, Jin-Ming

    2016-06-29

    High-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is considered a potential high-power-density positive electrode for lithium-ion batteries, however, it suffers from capacity decay after extended charge-discharge cycling, severely hindering commercial application. Capacity fade is thought to occur through the significant volume change of the LNMO electrode occurring on cycling, and in this work we use operando neutron powder diffraction to compare the structural evolution of the LNMO electrode in an as-assembled 18650-type battery containing a Li4Ti5O12 negative electrode with that in an identical battery following 1000 cycles at high-current. We reveal that the capacity reduction in the battery post cycling is directly proportional to the reduction in the maximum change of the LNMO lattice parameter during its evolution. This is correlated to a corresponding reduction in the MnO6 octahedral distortion in the spinel structure in the cycled battery. Further, we find that the rate of lattice evolution, which reflects the rate of lithium insertion and removal, is ∼9 and ∼10% slower in the cycled than in the as-assembled battery during the Ni(2+)/Ni(3+) and Ni(3+)/Ni(4+) transitions, respectively.

  12. Generation of large-scale, barrier-free diffuse plasmas in air at atmospheric pressure using array wire electrodes and nanosecond high-voltage pulses

    Science.gov (United States)

    Teng, Yun; Li, Lee; Liu, Yun-Long; Liu, Lun; Liu, Minghai

    2014-10-01

    This paper introduces a method to generate large-scale diffuse plasmas by using a repetition nanosecond pulse generator and a parallel array wire-electrode configuration. We investigated barrier-free diffuse plasmas produced in the open air in parallel and cross-parallel array line-line electrode configurations. We found that, when the distance between the wire-electrode pair is small, the discharges were almost extinguished. Also, glow-like diffuse plasmas with little discharge weakening were obtained in an appropriate range of line-line distances and with a cathode-grounding cross-electrode configuration. As an example, we produced a large-scale, stable diffuse plasma with volumes as large as 18 × 15 × 15 cm3, and this discharge region can be further expanded. Additionally, using optical and electrical measurements, we showed that the electron temperature was higher than the gas temperature, which was almost the same as room temperature. Also, an array of electrode configuration with more wire electrodes had helped to prevent the transition from diffuse discharge to arc discharge. Comparing the current waveforms of configurations with 1 cell and 9 cells, we found that adding cells significantly increased the conduction current and the electrical energy delivered in the electrode gaps.

  13. Selection of the Optimum Electrospray Voltage for Gradient Elution LC-MS Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Marginean, Ioan; Kelly, Ryan T.; Moore, Ronald J.; Prior, David C.; Lamarche, Brian L.; Tang, Keqi; Smith, Richard D.

    2009-04-01

    Changes in liquid composition during gradient elution liquid chromatography (LC) and mass spectrometry (MS) analyses affect the electrospray operation. To establish methodologies for judicious selection of the electrospray voltage, we monitored in real-time the effect of the LC gradient on the spray current. The optimum range of the electrospray voltage shifted to lower values as the concentration of organic solvent in the eluent increased during reversed-phase LC analyses. These results provided the means to rationally select the voltage that ensured successful electrospray operation throughout gradient elution LC-MS experiments. A small run-to-run drift in the spray current was observed for electrosprays operated at constant voltage. This could be the result of fouling or degradation of the electrospray emitter, which affected the electric field driving the electrospray. Algorithms using feedback from spray current measurements to maintain the electrospray voltage within the optimum operating range throughout gradient elution LC-MS were evaluated. The electrospray operation with voltage regulation and at constant, judiciously selected voltage during gradient elution LC-MS measurements produced data with similar reproducibility.

  14. Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7.

    Science.gov (United States)

    Nadzirah, Sh; Azizah, N; Hashim, Uda; Gopinath, Subash C B; Kashif, Mohd

    2015-01-01

    Nanoparticle-mediated bio-sensing promoted the development of novel sensors in the front of medical diagnosis. In the present study, we have generated and examined the potential of titanium dioxide (TiO2) crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA. The performance of this novel DNA biosensor was measured the electrical current response using a picoammeter. The sensor surface was chemically functionalized with (3-aminopropyl) triethoxysilane (APTES) to provide contact between the organic and inorganic surfaces of a single-stranded DNA probe and TiO2 nanoparticles while maintaining the sensing system's physical characteristics. The complement of the target DNA of E. coli O157:H7 to the carboxylate-probe DNA could be translated into electrical signals and confirmed by the increased conductivity in the current-to-voltage curves. The specificity experiments indicate that the biosensor can discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. After duplex formation, the complementary target sequence can be quantified over a wide range with a detection limit of 1.0 x 10(-13)M. With target DNA from the lysed E. coli O157:H7, we could attain similar sensitivity. Stability of DNA immobilized surface was calculated with the relative standard deviation (4.6%), displayed the retaining with 99% of its original response current until 6 months. This high-performance interdigitated DNA biosensor with high sensitivity, stability and non-fouling on a novel sensing platform is suitable for a wide range of biomolecular interactive analyses.

  15. Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7.

    Directory of Open Access Journals (Sweden)

    Sh Nadzirah

    Full Text Available Nanoparticle-mediated bio-sensing promoted the development of novel sensors in the front of medical diagnosis. In the present study, we have generated and examined the potential of titanium dioxide (TiO2 crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA. The performance of this novel DNA biosensor was measured the electrical current response using a picoammeter. The sensor surface was chemically functionalized with (3-aminopropyl triethoxysilane (APTES to provide contact between the organic and inorganic surfaces of a single-stranded DNA probe and TiO2 nanoparticles while maintaining the sensing system's physical characteristics. The complement of the target DNA of E. coli O157:H7 to the carboxylate-probe DNA could be translated into electrical signals and confirmed by the increased conductivity in the current-to-voltage curves. The specificity experiments indicate that the biosensor can discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. After duplex formation, the complementary target sequence can be quantified over a wide range with a detection limit of 1.0 x 10(-13M. With target DNA from the lysed E. coli O157:H7, we could attain similar sensitivity. Stability of DNA immobilized surface was calculated with the relative standard deviation (4.6%, displayed the retaining with 99% of its original response current until 6 months. This high-performance interdigitated DNA biosensor with high sensitivity, stability and non-fouling on a novel sensing platform is suitable for a wide range of biomolecular interactive analyses.

  16. Measurement of electrode-tissue interface impedance for improvement of a transcutaneous data transmission using human body as transmission medium.

    Science.gov (United States)

    Okamoto, Eiji; Kato, Yoshikuni; Kikuchi, Sakiko; Mitamura, Yoshinori

    2014-01-01

    The electrical property between an electrode and skin or tissue is one of the important issues for communication performance of the transcutaneous communication system (TCS) using a human body as a conductive medium.In this study, we used a simple method to measure interface resistance between the electrode and skin on the surface of the body. The electrode-electrode impedance was measured by a commercially available LCR meter with changes in the distance between two electrodes on an arm of a healthy male subject, and we obtained the tissue resistivity and electrode-skin interface resistance using the cross-sectional area of the arm.We also measured transmission gain of the TCS on the surface of the body, and we investigated the relationship between electrode-skin interface resistance and transmission gain. We examined four kinds of electrodes: a stainless steel electrode, a titanium electrode, an Ag-AgCl electrode and an Ag-AgCl paste electrode. The stainless steel electrode, which had lower electrode-skin resistance, had higher transmission gain.The results indicate that an electrode that has lower electrode-skin resistance will contribute to improvement of the performance of the TCS and that electrode-skin interface resistance is one of valuable evaluation parameters for selecting an optimum electrode for the TCS.

  17. The Applications of Current Comparators in the Measurements on High Voltage Insulation

    Directory of Open Access Journals (Sweden)

    Fei Yi-jun

    2016-01-01

    Full Text Available This paper describes the basic structure of the current comparator used for high voltage insulation measurements. Further applications for the current comparator in high voltage insulation are investigated and developed. A measuring system for the measurement of harmonics in the loss current of water tree aged insulation is described, as well as the principles to measure partial discharges with the current comparator bridge. A new system for the measurement of the DC component in the leakage current of insulation is de1veloped and presented. The results of experiments on XLPE cable insulation are also given.

  18. A thermoelectric voltage effect in polyethylene oxide

    CERN Document Server

    Martin, B; Kliem, H

    2003-01-01

    The conductivity of polyethylene oxide (PEO) is described with a three-dimensional hopping model considering electrostatic interactions between the ions. Ions fluctuate over energy-barriers in a multi-well potential. To decide whether positive or negative charges are responsible for this conductivity, the thermoelectric voltage is measured. The samples are embedded between two aluminium-electrodes. The oxide on the interface between the electrodes and the PEO serves as a blocking layer. The temperature of each electrode is controlled by a Peltier element. A temperature step is applied to one electrode by changing the temperature of one of the Peltier elements. Due to this temperature gradient, the mobile charges fluctuate thermally activated from the warmer side to the colder side of the sample. The direction of the measured thermoelectric voltage indicates the type of mobile charges. It is found that positive charges are mobile. Further, it is shown that the absolute value of the thermoelectric voltage depen...

  19. PD-Detection vs. Loss Measurements at High Voltages with variable frequencies

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Edin, Hans

    1999-01-01

    Partial discharge-activity (PD) in internal voids in epoxy plastic was measured at AC voltages from below inception to 3 times inception with variable frequencies in the range 0.1 to 100Hz.The results from phase/height analyses were compared to dielec-tric loss measurements and related to the app......Partial discharge-activity (PD) in internal voids in epoxy plastic was measured at AC voltages from below inception to 3 times inception with variable frequencies in the range 0.1 to 100Hz.The results from phase/height analyses were compared to dielec-tric loss measurements and related...

  20. Comparison of non-polarising electrode designs for measuring electrical properties in biogeophysics experiments

    Science.gov (United States)

    West, L. J.; Hubbard, C. G.; Morris, K.; Shaw, S.

    2009-12-01

    An increasing number of laboratory studies are investigating the link between microbial biogeochemical processes, such as the bioreduction of Fe(III) and sulfate, and geophysical responses. Self Potential (SP) and Induced Polarization (IP) studies both use non-polarisable electrodes to measure these responses. Commonly used electrodes include Ag with AgCl coating, in direct contact with the solution chemistry of the experiment being performed. However, this arrangement can lead to alteration and degradation of the AgCl coating, for example by formation of AgS, resulting in signals from a galvanic response. In this contribution, we directly compare the performance of two alternative electrode arrangements for monitoring SP and IP in laboratory column experiments. The first arrangement uses inexpensive, plastic-bodied, commercially available Ag/AgCl reference electrodes in a KCl gel, offering ease of use. The second arrangement uses miniaturized, laboratory-constructed Pb/PbCl2 “Petiau” electrodes. Petiau electrodes are commonly used in field SP investigations and their dimensions can be tailored for specific laboratory experiment requirements. The performance of these electrodes in aqueous solutions of known conductivity was compared. The measured SP between electrode pairs in the same conductive solution, which should theoretically be zero, was < 2 mV for Petiau electrodes and < 1.2 mV for Ag/AgCl electrodes. However, Petiau electrodes showed greater accuracy and reproducibility when used for conductivity (IP) measurements. The results from the use of both types of electrodes in column experiments with biologically active sediments will be reported.

  1. An Efficient approach for Shielding Effect of the Grounding Electrodes under Impulse-Current Voltage based on MATLAB

    Directory of Open Access Journals (Sweden)

    Kalyani Pole

    2012-06-01

    Full Text Available The lightning current waveform has a major influence on the dynamic performance of ground electrodes. While high lightning current intensity improves the dynamic grounding performance due to ionization of the soil, very fast fronted pulses might worsen the performance in case of inductive behaviour. The previous analysis has often been based on quasistatic approximation that is not applicable to very fast fronted pulses. Previous Research focused on analyzing the impulse current dispersal regularity of different branches when injecting at one point. Comparing with the leakage current distribution of a single ground electrode, it is found that the leakage currents along the branches increase with the distance to the current feed point, and the more conductors near the injection point, the more uneven the leakage current distribution is. In this paper by simulation result we indicate that shielding effect should be taken into account when analyzing the impulse characteristics of grounding electrodes. Based on the simulation results, new empirical formulas applicable for slow and very fast fronted lightning current pulses are proposed. The effects of the ionization of the soil are disregarded; therefore, the new formulas are applicable for a conservative estimate of the upper bound of the impulse impedance of ground electrodes. In this paper we also analyze and compare by the MATLAB. We also provide dynamic behavior of ground electrodes.

  2. Relationship between Work Function of Hole Collection Electrode and Temperature Dependence of Open-Circuit Voltage in Multilayered Organic Solar Cells

    Science.gov (United States)

    Itoh, Eiji; Shirotori, Toshiki

    2012-02-01

    We have investigated the photovoltaic properties of multilayered organic photovoltaic devices consisting of indium tin oxide (ITO)/(NiO)/donor/C60/bathocuproine (BCP)/Al structures. Open circuit voltage (VOC) increases with the decrease in temperature between 40 and 350 K. The VOC was, however, pinned at approximately 0.6 V for the device without NiO, probably owing to the insufficient work-function difference between ITO and Al electrodes. The hole injection was also markedly suppressed at the ITO/donor interface in the device with large IP donor materials without the buffer layer and abnormal S-shaped current density-voltage (J-V) characteristics were observed. On the other hand, the value of VOC increases with the increase in ionization potential (IP) of donor materials in the device with NiO buffer layers owing to the enhanced work-function difference of about 1 eV, and the S-shaped curves disappeared at the high temperatures above 200 K. The VOC is further improved to nearly 1.2 V by the UV-ozone treatment of the NiO surface. We have therefore concluded that the increment of work function of the anode caused by the insertion of an oxide buffer layer and the surface treatment of the electrode by UV-ozone treatment are essentially important for the improvement of VOC and charge transport/injection properties in the multilayered organic solar cell applications.

  3. The Coefficient of the Voltage Induced Frequency Shift Measurement on a Quartz Tuning Fork

    Directory of Open Access Journals (Sweden)

    Yubin Hou

    2014-11-01

    Full Text Available We have measured the coefficient of the voltage induced frequency shift (VIFS of a 32.768 KHz quartz tuning fork. Three vibration modes were studied: one prong oscillating, two prongs oscillating in the same direction, and two prongs oscillating in opposite directions. They all showed a parabolic dependence of the eigen-frequency shift on the bias voltage applied across the fork, due to the voltage-induced internal stress, which varies as the fork oscillates. The average coefficient of the VIFS effect is as low as several hundred nano-Hz per millivolt, implying that fast-response voltage-controlled oscillators and phase-locked loops with nano-Hz resolution can be built.

  4. A Grid Voltage Measurement Method for Wind Power Systems during Grid Fault Conditions

    Directory of Open Access Journals (Sweden)

    Cheol-Hee Yoo

    2014-11-01

    Full Text Available Grid codes in many countries require low-voltage ride-through (LVRT capability to maintain power system stability and reliability during grid fault conditions. To meet the LVRT requirement, wind power systems must stay connected to the grid and also supply reactive currents to the grid to support the recovery from fault voltages. This paper presents a new fault detection method and inverter control scheme to improve the LVRT capability for full-scale permanent magnet synchronous generator (PMSG wind power systems. Fast fault detection can help the wind power systems maintain the DC-link voltage in a safe region. The proposed fault detection method is based on on-line adaptive parameter estimation. The performance of the proposed method is verified in comparison to the conventional voltage measurement method defined in the IEC 61400-21 standard.

  5. Novel active comb-shaped dry electrode for EEG measurement in hairy site.

    Science.gov (United States)

    Huang, Yan-Jun; Wu, Chung-Yu; Wong, Alice May-Kuen; Lin, Bor-Shyh

    2015-01-01

    Electroencephalography (EEG) is an important biopotential, and has been widely applied in clinical applications. The conventional EEG electrode with conductive gels is usually used for measuring EEG. However, the use of conductive gel also encounters with the issue of drying and hardening. Recently, many dry EEG electrodes based on different conductive materials and techniques were proposed to solve the previous issue. However, measuring EEG in the hairy site is still a difficult challenge. In this study, a novel active comb-shaped dry electrode was proposed to measure EEG in hairy site. Different form other comb-shaped or spike-shaped dry electrodes, it can provide more excellent performance of avoiding the signal attenuation, phase distortion, and the reduction of common mode rejection ratio. Even under walking motion, it can effectively acquire EEG in hairy site. Finally, the experiments for alpha rhythm and steady-state visually evoked potential were also tested to validate the proposed electrode.

  6. A Study on Measurement Error during Alternating Current Induced Voltage Tests on Large Transformers

    Institute of Scientific and Technical Information of China (English)

    WANG Xuan; LI Yun-ge; CAO Xiao-long; LIU Ying

    2006-01-01

    The large transformer is pivotal equipment in an electric power supply system; Its partial discharge test and the induced voltage withstand test on large transformers are carried out at a frequency about twice the working frequency. If the magnetizing inductance cannot compensate for the stray capacitance, the test sample turns into a capacitive load and a capacitive rise exhibits in the testing circuit. For self-restoring insulation, a method has been recommended in IEC60-1 that an unapproved measuring system be calibrated by an approved system at a voltage not less than 50% of the rated testing voltage, and the result then be extrapolated linearly. It has been found that this method leads to great error due to the capacitive rise if it is not correctly used during a withstand voltage test under certain testing conditions, especially for a test on high voltage transformers with large capacity. Since the withstand voltage test is the most important means to examine the operation reliability of a transformer, and it can be destructive to the insulation, a precise measurement must be guaranteed. In this paper a factor, named as the capacitive rise factor, is introduced to assess the rise. The voltage measurement error during the calibration is determined by the parameters of the test sample and the testing facilities, as well as the measuring point. Based on theoretical analysis in this paper, a novel method is suggested and demonstrated to estimate the error by using the capacitive rise factor and other known parameters of the testing circuit.

  7. Comparison of dry-textile electrodes for electrical bioimpedance spectroscopy measurements

    Science.gov (United States)

    Márquez, J. C.; Seoane, F.; Välimäki, E.; Lindecrantz, K.

    2010-04-01

    Textile Electrodes have been widely studied for biopotentials recordings, specially for monitoring the cardiac activity. Commercially available applications, such as Adistar T-shirt and Textronics Cardioshirt, have proved a good performance for heart rate monitoring and are available worldwide. Textile technology can also be used for Electrical Bioimpedance Spectroscopy measurements enabling home and personalized health monitoring applications however solid ground research about the measurement performance of the electrodes must be done prior to the development of any textile-enabled EBI application. In this work a comparison of the measurement performance of two different types of dry-textile electrodes and manufacturers has been performed against standardized RedDot 3M Ag/AgCl electrolytic electrodes. 4-Electrode, whole body, Ankle-to-Wrist EBI measurements have been taken with the Impedimed spectrometer SFB7 from healthy subjects in the frequency range of 3kHz to 500kHz. Measurements have been taken with dry electrodes at different times to study the influence of the interaction skin-electrode interface on the EBI measurements. The analysis of the obtained complex EBI spectra shows that the measurements performed with textile electrodes produce constant and reliable EBI spectra. Certain deviation can be observed at higher frequencies and the measurements obtained with Textronics and Ag/AgCl electrodes present a better resemblance. Textile technology, if successfully integrated it, may enable the performance of EBI measurements in new scenarios allowing the rising of novel wearable monitoring applications for home and personal care as well as car safety.

  8. Measurement of Spin Pumping Voltage Separated from Extrinsic Microwave Effects

    Science.gov (United States)

    Iguchi, Ryo; Saitoh, Eiji

    2017-01-01

    Conversions between spin and charge currents are core technologies in recent spintronics. In this article, we provide methods for estimating inverse spin Hall effects (ISHEs) induced by using microwave-driven spin pumping (SP) as a spin-current generator. ISHE and SP induce an electromotive force at the ferromagnetic or spin-wave resonance, which offers a valuable electric method of studying spin physics in materials. At the resonance, a microwave for exciting the magnetization dynamics induces an additional electromotive force via rf-current rectification and thermoelectric effects. We discuss methods of separating the signals generated from such extrinsic microwave effects by controlling sample structures and configurations. These methods are helpful in performing accurate measurements on ISHE induced by SP, enabling quantitative studies on the conversion between spin and charge currents on various kinds of materials.

  9. An Efficient approach for Shielding Effect of the Grounding Electrodes under Impulse-Current Voltage based on Matlab

    Directory of Open Access Journals (Sweden)

    Ms. Kalyani Pole

    2012-06-01

    Full Text Available The lightning current waveform has a majorinfluence on the dynamic performance of groundelectrodes. While high lightning current intensityimproves the dynamic grounding performance dueto ionization of the soil, very fast fronted pulsesmight worsen the performance in case of inductivebehaviour. The previous analysis has often beenbased on quasistatic approximation that is notapplicable to very fast fronted pulses. PreviousResearch focused on analyzing the impulse currentdispersal regularity of different branches wheninjecting at one point. Comparing with the leakagecurrent distribution of a single ground electrode, itis found that the leakage currents along thebranches increase with the distance to the currentfeed point, and the more conductors near theinjection point, the more uneven the leakagecurrent distribution is. In this paper by simulationresult we indicate that shielding effect should betaken into account when analyzing the impulsecharacteristics of grounding electrodes. Based onthe simulation results, new empirical formulasapplicable for slow and very fast fronted lightningcurrent pulses are proposed. The effects of theionization of the soil are disregarded; therefore, thenew formulas are applicable for a conservativeestimate of the upper bound of the impulseimpedance of ground electrodes. In this paper wealso analyze and compare by the MATLAB. We alsoprovide dynamic behavior of ground electrodes.

  10. The PPTN-02 new-generation current-voltage transducers for measuring of photosignals

    Directory of Open Access Journals (Sweden)

    Butenko V. K.

    2008-02-01

    Full Text Available The measurement results of technical characteristics of new-generation current-voltage transducers which have low input resistance (<10 Оhm and providing ptotodiodes photocurrent measurement from 1·10-12 to 1·10-3 A are presented.

  11. Measurement system for determination of current-voltage characteristics of PV modules

    Science.gov (United States)

    Idzkowski, Adam; Walendziuk, Wojciech; Borawski, Mateusz; Sawicki, Aleksander

    2015-09-01

    The realization of a laboratory stand for testing photovoltaic panels is presented here. The project of the laboratory stand was designed in SolidWorks software. The aim of the project was to control the electrical parameters of a PV panel. For this purpose a meter that measures electrical parameters i.e. voltage, current and power, was realized. The meter was created with the use of LabJack DAQ device and LabVIEW software. The presented results of measurements were obtained in different conditions (variable distance from the source of light, variable tilt angle of the panel). Current voltage characteristics of photovoltaic panel were created and all parameters could be detected in different conditions. The standard uncertainties of sample voltage, current, power measurements were calculated. The paper also gives basic information about power characteristics and efficiency of a solar cell.

  12. Skin-electrode impedance measurement during ECG acquisition: method’s validation

    Science.gov (United States)

    Casal, Leonardo; La Mura, Guillermo

    2016-04-01

    Skm-electrode impedance measurement can provide valuable information prior. dunng and post electrocardiographic (ECG) or electroencephalographs (EEG) acquisitions. In this work we validate a method for skm-electrode impedance measurement using test circuits with known resistance and capacitor values, at different frequencies for injected excitation current. Finally the method is successfully used for impedance measurement during ECG acquisition on a subject usmg 125 Hz and 6 nA square wave excitation signal at instrumentation amplifier mput. The method can be used for many electrodes configuration.

  13. Studying the Performance of Conductive Polymer Films as Textile Electrodes for Electrical Bioimpedance Measurements

    Science.gov (United States)

    Cunico, F. J.; Marquez, J. C.; Hilke, H.; Skrifvars, M.; Seoane, F.

    2013-04-01

    With the goal of finding novel biocompatible materials suitable to replace silver in the manufacturing of textile electrodes for medical applications of electrical bioimpedance spectroscopy, three different polymeric materials have been investigated. Films have been prepared from different polymeric materials and custom bracelets have been confectioned with them. Tetrapolar total right side electrical bioimpedance spectroscopy (EBIS) measurements have been performed with polymer and with standard gel electrodes. The performance of the polymer films was compared against the performance of the gel electrodes. The results indicated that only the polypropylene 1380 could produce EBIS measurements but remarkably tainted with high frequency artefacts. The influence of the electrode mismatch, stray capacitances and large electrode polarization impedance are unclear and they need to be clarified with further studies. If sensorized garments could be made with such biocompatible polymeric materials the burden of considering textrodes class III devices could be avoided.

  14. Evaluation of a novel correction procedure to remove electrode impedance effects from broadband SIP measurements

    Science.gov (United States)

    Huisman, Johan Alexander; Zimmermann, Egon; Esser, Odilia; Haegel, Franz-Hubert; Treichel, Andrea; Vereecken, Harry

    2016-12-01

    Broadband spectral induced polarization (SIP) measurements of the complex electrical resistivity can be affected by the contact impedance of the potential electrodes above 100 Hz. In this study, we present a correction procedure to remove electrode impedance effects from SIP measurements to improve the accuracy of broadband complex electrical resistivity measurements. The first step in this correction procedure is to estimate the electrode impedance using a measurement with reversed current and potential electrodes. In a second step, this estimated electrode impedance is used to correct SIP measurements based on a simplified electrical model of the SIP measurement system. We evaluated this new correction procedure using SIP measurements on water because of the well-defined dielectric properties. It was found that the difference between the corrected and expected phase of the complex electrical resistivity of water was below 0.1 mrad at 1 kHz for a wide range of electrode impedances. In addition, SIP measurements on a saturated unconsolidated sediment sample with two types of potential electrodes showed that the measured phase of the electrical resistivity was very similar (difference resistivity was improved for frequencies up to 1 kHz, but errors remained for higher frequencies due to the approximate nature of the electrode impedance estimates and some remaining unknown parasitic capacitances that led to current leakage. It was concluded that the proposed correction procedure for SIP measurements improved the accuracy of the phase measurements by an order of magnitude in the kHz frequency range. Further improvement of this accuracy requires a method to accurately estimate parasitic capacitances in situ.

  15. A test technique for measuring lightning-induced voltages on aircraft electrical circuits

    Science.gov (United States)

    Walko, L. C.

    1974-01-01

    The development of a test technique used for the measurement of lightning-induced voltages in the electrical circuits of a complete aircraft is described. The resultant technique utilizes a portable device known as a transient analyzer capable of generating unidirectional current impulses similar to lightning current surges, but at a lower current level. A linear relationship between the magnitude of lightning current and the magnitude of induced voltage permitted the scaling up of measured induced values to full threat levels. The test technique was found to be practical when used on a complete aircraft.

  16. Electrode-Skin contact impedance: In vivo measurements on an ovine model

    Science.gov (United States)

    Nguyen, D. T.; Kosobrodov, R.; Barry, M. A.; Chik, W.; Jin, C.; Oh, T. I.; Thiagalingam, A.; McEwan, A.

    2013-04-01

    The problem of electrical impedance between the skin and the electrode is an on-going challenge in bio-electronics. This is particularly true in the case of Electrical Impedance Tomography (EIT), which uses a large number of skin-contact electrodes and is very sensitive to noise. In the present article, contact impedance is measured and compared for a range of electrodes placed on the thorax of an ovine model. The study has been approved by the Westmead Hospital Animal Ethics Committee. The electrode models that were employed in the research are Ag/AgCl electrodes (E1), commonly used for ECG and EIT measurements in both humans and animal models, stainless steel crocodile clips (E2), typically used on animal models, and novel multi-point dry electrodes in two modifications: bronze plated (E3) and nickel plated (E4). Further, since the contact impedance is mostly attributed to the acellular outer layer of the skin, in our experiment, we attempted to study the effect of this layer by comparing the results when the skin is intact and when electrodes are introduced underneath the skin through small cuts. This boundary effect was assessed by comparison of measurements obtained during E2 skin surface contact, and sub-cutaneous contact (E5). Twelve gauge intradermal needles were also tested as an electrode (E6). The full impedance spectrum, from 500 Hz to 300 kHz, was recorded, analysed and compared. As expected, the contact impedance in the more invasive cases, i.e the electrodes under the skin, is significantly lower than in the non-invasive cases. At the frequency of 50 kHz which is commonly used in lung EIT acquisition, electrodes E3, E4 and E6 demonstrated contact impedance of less than 200 Ω, compared to more than 400 Ω measured for electrodes E1, E2 and E5. In conclusion, the novel multipoint electrodes proved to be best suited for EIT purposes, because they are non-invasive and have lower contact impedance than Ag/AgCl and crocodile clips, in both invasive and

  17. Electrode placement in bioimpedance spectroscopy: evaluation of alternative positioning of electrodes when measuring relative dehydration in athletes.

    Science.gov (United States)

    Birkemose, M; Møller, A J; Madsen, M L; Brantlov, S; Sørensen, H; Overgaard, K; Johansen, P

    2013-01-01

    In order to maintain a homeostatic environment in human cells, the balance between absorption and separation of water must be retained. Imbalance will have consequences on both the cellular and organ levels. Studies performed on athletes have shown coherence between their hydration status and ability to perform. A dehydration of 2-7% of total body weight resulted in a marked decrease in performance. Measurement and monitoring of hydration status may be used to optimize athlete performance. Therefore, in this current study bioimpedance spectroscopy is used to determine the hydration status of athletes. Trials were made to investigate alternative ways of electrode placement when performing bioimpedance spectroscopy in order to measure relative dehydration. A total of 14 test subjects underwent measurements before, during, and after a cycle test of 3×25min. Electrodes where placed to measure body impedance in three different ways: wrist-ankle (recommended method), wrist-wrist, and transthoracic. Furthermore, the relative loss in weight of the subjects during the trial was registered. The study showed no relation between relative weight loss and the wrist-wrist and transthoracic placement method, using bioimpedance spectroscopy to measure relative dehydration. The inability of the method to detect such relative changes in hydration may be due to the bioimpedance spectroscopy technology being extremely sensitive to changes in skin temperature, movement artifacts, thoroughness in placing the electrodes, and the physiological impact on the human body when performing exercise. Therefore, further research into the area of bioimpedance spectroscopy is needed before this methodology can be applied in monitoring active athletes. Hence, a simple weight measurement still seems a more useful way of determining a relative change of hydration in an active setting.

  18. ZnO(CdS)/CIS/Mo solar cells characterized by modulation capacitance voltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sinh, N.D.; Scheer, R.; Kliefoth, K.; Fuessel, W.; Fuhs, W. [Hahn-Meitner-Inst., Berlin (Germany)

    1997-12-31

    From Modulation Capacitance Voltage (MCV) measurements the authors determined a voltage V{sub s} of several hundred mV at the depletion region in CuInS{sub 2} under PV generator and short circuit working conditions. In this solar cell type electron transport through shallow gap states in the CdS interlayer enhances interface recombination which increases the dark current. The CuInSe{sub 2} solar cells show a different behavior. In darkness, electron emission into the depletion region over a barrier of more than 500 mV was measured, and voltage losses while working as PV generator remain nearly constant below 60 mV. The authors interpret these results by a blocking CuInS{sub 2}/Mo contact and a band spike at the CdS/CuInSe{sub 2} junction.

  19. In Situ Measurement of Voltage-Induced Stress in Conducting Polymers with Redox-Active Dopants.

    Science.gov (United States)

    Sen, Sujat; Kim, Sung Yeol; Palmore, Lia R; Jin, Shenghua; Jadhav, Nitin; Chason, Eric; Palmore, G Tayhas R

    2016-09-14

    Minimization of stress-induced mechanical rupture and delamination of conducting polymer (CP) films is desirable to prevent failure of devices based on these materials. Thus, precise in situ measurement of voltage-induced stress within these films should provide insight into the cause of these failure mechanisms. The evolution of stress in films of polypyrrole (pPy), doped with indigo carmine (IC), was measured in different electrochemical environments using the multibeam optical stress sensor (MOSS) technique. The stress in these films gradually increases to a constant value during voltage cycling, revealing an initial break-in period for CP films. The nature of the ions involved in charge compensation of pPy[IC] during voltage cycling was determined from electrochemical quartz crystal microbalance (EQCM) data. The magnitude of the voltage-induced stress within pPy[IC] at neutral pH correlated with the radius of the hydrated mobile ion in the order Li(+) > Na(+) > K(+). At acidic pH, the IC dopant in pPy[IC] undergoes reversible oxidation and reduction within the range of potentials investigated, providing a secondary contribution to the observed voltage-induced stress. We report on the novel stress response of these polymers due to the presence of pH-dependent redox-active dopants and how it can affect material performance.

  20. Electrode size and boundary condition independent measurement of the effective piezoelectric coefficient of thin films

    Directory of Open Access Journals (Sweden)

    M. Stewart

    2015-02-01

    Full Text Available The determination of the piezoelectric coefficient of thin films using interferometry is hindered by bending contributions. Using finite element analysis (FEA simulations, we show that the Lefki and Dormans approximations using either single or double-beam measurements cannot be used with finite top electrode sizes. We introduce a novel method for characterising piezoelectric thin films which uses a differential measurement over the discontinuity at the electrode edge as an internal reference, thereby eliminating bending contributions. This step height is shown to be electrode size and boundary condition independent. An analytical expression is derived which gives good agreement with FEA predictions of the step height.

  1. Particle trapping and impedance measurement using bilayer electrodes integrated with microcavity structure

    Science.gov (United States)

    Chen, Guan-Ting; Liu, Chia-Feng; Jang, Ling-Sheng; Li, Shun-Lai; Wang, Min-Haw

    2017-03-01

    Traditional planar electrodes for single-particle impedance measurement have difficulty in trapping and positioning particles. This paper proposes a microfluidic device for single-particle trapping and impedance measurement with a microcavity configuration. A carbon dioxide (CO2) laser technique was used to fabricate the microcavity structure, which can capture 15 µm diameter particles without requiring additional trapping structures. The measurement electrodes on both sides of the microcavity were fabricated using electroplating and deposition techniques. The advantages of the microcavity structure and electrodes are discussed. The bottom electrode spreads into the microcavity to increase measurement sensitivity and shrink the exit aperture to around 10 µm for particle trapping. The experimental results show that the device successfully captured particles and distinguished the impedance of a particle from that of phosphate-buffered saline solution.

  2. A new measurement method of electrode gains for orthogonal symmetric type beam position monitor

    CERN Document Server

    Zou, J Y; Yang, Y L; Sun, B G; Zhou, Z R; Luo, Q; Lu, P; Xu, H L

    2014-01-01

    The new beam position monitor (BPM) system of the injector at the upgrade project of Hefei Light Source (HLS II) has 19 stripline beam position monitors. Most consist of four orthogonal symmetric stripline electrodes. The differences in electronic gain and mismachining tolerance can cause the change of the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions in order to bring the measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is irrelevant to the beam charge and the related coefficient can be theoretical calculated. The effect of electrodes coupling on this technique is analyzed. The calibration data is used to fit the gain for all 19 injector beam position monitors. The results show the standard deviation of the distribution of measured gains is about 5%.

  3. Focused ion beam processing to fabricate ohmic contact electrodes on a bismuth nanowire for Hall measurements

    OpenAIRE

    Murata, Masayuki; Hasegawa, Yasuhiro

    2013-01-01

    Ohmic contact electrodes for four-wire resistance and Hall measurements were fabricated on an individual single-crystal bismuth nanowire encapsulated in a cylindrical quartz template. Focused ion beam processing was utilized to expose the side surfaces of the bismuth nanowire in the template, and carbon and tungsten electrodes were deposited on the bismuth nanowire in situ to achieve electrical contacts. The temperature dependence of the four-wire resistance was successfully measured for the ...

  4. Spectroscopic measurements with a silicon drift detector having a continuous implanted drift cathode-voltage divider

    CERN Document Server

    Bonvicini, V; D'Acunto, L; Franck, D; Gregorio, A; Pihet, P; Rashevsky, A; Vacchi, A; Vinogradov, L I; Zampa, N

    2000-01-01

    A silicon drift detector (SDD) prototype where the drift electrode also plays the role of a high-voltage divider has been realised and characterised for spectroscopic applications at near-room temperatures. Among the advantages of this design, is the absence of metal on the sensitive surface which makes this detector interesting for soft X-rays. The detector prototype has a large sensitive area (2x130 mm sup 2) and the charge is collected by two anodes (butterfly-like detector). The energy resolution of a such a detector has been investigated at near-room temperatures using a commercial, hybrid, low-noise charge-sensitive preamplifier. The results obtained for the X-ray lines from sup 5 sup 5 Fe and sup 2 sup 4 sup 1 Am are presented.

  5. A new method for measuring the Faradic resistance of a single electrode-electrolyte interface.

    Science.gov (United States)

    Mayer, S; Geddes, L A; Bourland, J D; Ogborn, L

    1992-03-01

    A new method is described for measuring the Faradic resistance of a single electrode-electrolyte interface. The method employs a test (monopolar) electrode, a potential-sensing electrode and a large reference (indifferent) electrode, along with a constant-current source capable of providing a step function of current. The method was used to measure the Faradic resistance of a 0.1 cm2 platinum electrode in contact with saline (p = 150 ohm-cm) at room temperature. It was found that for both a positive and negative current pulse, the Faradic resistance decreased almost hyperbolically with increasing current density. When the reciprocal of the Faradic resistance (Gf) was plotted versus current density and the data were fit to a polynomial curve, the results showed that for the positive pulse Gf = 0.009 + 0.05J - 0.0001J2; (SEE = 0.117); for the negative pulse, Gf = 0.007 + 0.067J - 0.0001J2; (SEE = 0.028); where Gf is in millisiemens and J is in mA/cm2 for this 0.1 cm2 electrode. These relationships permit estimating the Faradic resistance (Rf) for zero current density. For the positive pulse, Rf = 111 kilohms and for the negative pulse Rf = 143 kilohms. The method is applicable to the measurement of the Faradic resistance of a wide variety of metal electrodes.

  6. Potentiometric measurement of polymer-membrane electrodes based on lanthanum

    Energy Technology Data Exchange (ETDEWEB)

    Saefurohman, Asep, E-mail: saefurohman.asep78@Gmail.com; Buchari,, E-mail: saefurohman.asep78@Gmail.com; Noviandri, Indra, E-mail: saefurohman.asep78@Gmail.com [Department of Chemistry, Bandung Institute of Technology (Indonesia); Syoni [Department of Metallurgy Engineering, Bandung Institute of Technology (Indonesia)

    2014-03-24

    Quantitative analysis of rare earth elements which are considered as the standard method that has a high accuracy, and detection limits achieved by the order of ppm is inductively coupled plasma atomic emission spectroscopy (ICPAES). But these tools are expensive and valuable analysis of the high cost of implementation. In this study be made and characterized selective electrode for the determination of rare earth ions is potentiometric. Membrane manufacturing techniques studied is based on immersion (liquid impregnated membrane) in PTFE 0.5 pore size. As ionophores to be used tri butyl phosphate (TBP) and bis(2-etylhexyl) hydrogen phosphate. There is no report previously that TBP used as ionophore in polymeric membrane based lanthanum. Some parameters that affect the performance of membrane electrode such as membrane composition, membrane thickness, and types of membrane materials studied in this research. Manufacturing of Ion Selective Electrodes (ISE) Lanthanum (La) by means of impregnation La membrane in TBP in kerosene solution has been done and showed performance for ISE-La. FTIR spectrum results for PTFE 0.5 pore size which impregnated in TBP and PTFE blank showed difference of spectra in the top 1257 cm{sup −1}, 1031 cm{sup −1} and 794.7 cm{sup −1} for P=O stretching and stretching POC from group −OP =O. The result showed shift wave number for P =O stretching of the cluster (−OP=O) in PTFE-TBP mixture that is at the peak of 1230 cm{sup −1} indicated that no interaction bond between hydroxyl group of molecules with molecular clusters fosforil of TBP or R{sub 3}P = O. The membrane had stable responses in pH range between 1 and 9. Good responses were obtained using 10{sup −3} M La(III) internal solution, which produced relatively high potential. ISE-La showed relatively good performances. The electrode had a response time of 29±4.5 second and could be use for 50 days. The linear range was between 10{sup −5} and 10{sup −1} M.

  7. Voltage measurements at the vacuum post-hole convolute of the Z pulsed-power accelerator

    Directory of Open Access Journals (Sweden)

    E. M. Waisman

    2014-12-01

    Full Text Available Presented are voltage measurements taken near the load region on the Z pulsed-power accelerator using an inductive voltage monitor (IVM. Specifically, the IVM was connected to, and thus monitored the voltage at, the bottom level of the accelerator’s vacuum double post-hole convolute. Additional voltage and current measurements were taken at the accelerator’s vacuum-insulator stack (at a radius of 1.6 m by using standard D-dot and B-dot probes, respectively. During postprocessing, the measurements taken at the stack were translated to the location of the IVM measurements by using a lossless propagation model of the Z accelerator’s magnetically insulated transmission lines (MITLs and a lumped inductor model of the vacuum post-hole convolute. Across a wide variety of experiments conducted on the Z accelerator, the voltage histories obtained from the IVM and the lossless propagation technique agree well in overall shape and magnitude. However, large-amplitude, high-frequency oscillations are more pronounced in the IVM records. It is unclear whether these larger oscillations represent true voltage oscillations at the convolute or if they are due to noise pickup and/or transit-time effects and other resonant modes in the IVM. Results using a transit-time-correction technique and Fourier analysis support the latter. Regardless of which interpretation is correct, both true voltage oscillations and the excitement of resonant modes could be the result of transient electrical breakdowns in the post-hole convolute, though more information is required to determine definitively if such breakdowns occurred. Despite the larger oscillations in the IVM records, the general agreement found between the lossless propagation results and the results of the IVM shows that large voltages are transmitted efficiently through the MITLs on Z. These results are complementary to previous studies [R. D. McBride et al., Phys. Rev. ST Accel. Beams 13, 120401 (2010

  8. Determination of perpendicular magnetic anisotropy in ultrathin ferromagnetic films by extraordinary Hall voltage measurement.

    Science.gov (United States)

    Moon, Kyoung-Woong; Lee, Jae-Chul; Choe, Sug-Bong; Shin, Kyung-Ho

    2009-11-01

    A magnetometric technique for detecting the magnetic anisotropy field of ferromagnetic films is described. The technique is based on the extraordinary Hall voltage measurement with rotating the film under an external magnetic field. By analyzing the angle-dependent Hall voltage based on the Stoner-Wohlfarth theory, the magnetic anisotropy field is uniquely determined. The present technique is pertinent especially for ultrathin films with strong intrinsic signal, in contrast to the conventional magnetometric techniques of which the signal is in proportion to the sample volume and geometry.

  9. Experimental Measurements of e-Cloud Mitigation Using Clearing Electrodes in the DAФNE Collider

    CERN Document Server

    Alesini, D; Gallo, A; Guiducci, S; Milardi, C; Zobov, M; De Santis, S; Demma, Theo; Raimondi, P

    2012-01-01

    Recently the DAФNE electron-positron collider has started delivering luminosity to the KLOE-2 experiment. For this run special metallic electrodes were installed in all the dipole and wiggler magnets of the positron ring to cope with the effects induced by the e-cloud formation. Experimental measurements have shown an impressive effectiveness of these devices in mitigating the e-cloud impact on the positron beam dynamics. The electrodes allow reducing the vertical beam size and the growth rate of transverse instabilities as well as the tune shifts induced by the electron cloud itself. Moreover frequency shift measurements of the vacuum chamber resonances, switching on and off the electrodes, indicate an evident reduction of the electron cloud density. This paper reports and analyses all the experimental observations and measurements done to suppress the e-cloud induced effects by using metallic electrodes.

  10. A detailed procedure for measuring turbulent velocity fluctuations using constant-voltage anemometry

    Science.gov (United States)

    Mohammed-Taifour, Abdelouahab; Weiss, Julien; Sadeghi, Atabak; Vétel, Jérôme; Jondeau, Emmanuel; Comte-Bellot, Geneviève

    2015-09-01

    A detailed procedure to use a constant-voltage anemometer (CVA) for the accurate measurement of turbulent flows is proposed. The procedure is based on the usual small-perturbation analysis of hot-wire signals. It consists in three steps: (1) the calibration of internal elements, required to estimate the two main electrical parameters of the CVA circuitry that are needed in the data analysis, (2) a flow calibration to relate the CVA output voltage and the hot-wire time constant to the flow velocity, and (3) a data-processing algorithm to recover the fluctuating flow quantities from the output voltage. The procedure is tested in two classical turbulent flows: a zero-pressure-gradient boundary layer and a round jet. In both cases, the CVA results are shown to be essentially indistinguishable from the results obtained with a research-grade constant-temperature anemometer.

  11. Assessing the high frequency behavior of non-polarizable electrodes for spectral induced polarization measurements

    Science.gov (United States)

    Abdulsamad, Feras; Florsch, Nicolas; Schmutz, Myriam; Camerlynck, Christian

    2016-12-01

    During the last decades, the usage of spectral induced polarization (SIP) measurements in hydrogeology and detecting environmental problems has been extensively increased. However, the physical mechanisms which are responsible for the induced polarization response over the usual frequency range (typically 1 mHz to 10-20 kHz) require better understanding. The phase shift observed at high frequencies is sometimes attributed to the so-called Maxwell-Wagner polarization which takes place when charges cross an interface. However, SIP measurements of tap water show a phase shift at frequencies higher than 1 kHz, where no Maxwell-Wagner polarization may occur. In this paper, we enlighten the possible origin of this phase shift and deduce its likely relationship with the types of the measuring electrodes. SIP Laboratory measurements of tap water using different types of measuring electrodes (polarizable and non-polarizable electrodes) are carried out to detect the origin of the phase shift at high frequencies and the influence of the measuring electrodes types on the observed complex resistivity. Sodium chloride is used to change the conductivity of the medium in order to quantify the solution conductivity role. The results of these measurements are clearly showing the impact of the measuring electrodes type on the measured phase spectrum while the influence on the amplitude spectrum is negligible. The phenomenon appearing on the phase spectrum at high frequency (> 1 kHz) whatever the electrode type is, the phase shows an increase compared to the theoretical response, and the discrepancy (at least in absolute value) increases with frequency, but it is less severe when medium conductivity is larger. Additionally, the frequency corner is shifted upward in frequency. The dependence of this phenomenon on the conductivity and the measuring electrodes type (electrode-electrolyte interface) seems to be due to some dielectric effects (as an electrical double layer of small

  12. Cochlear implant electrode localization in post-operative CT using a spherical measure

    DEFF Research Database (Denmark)

    Braithwaite, Benjamin Michael; Kjer, Hans Martin; Fagertun, Jens;

    2016-01-01

    the ordering of electrode contacts on implanted electrode arrays from post-operative CT images. Our method applies a specialized filter chain to the images based on a threshold and spherical measure, and selects contact positions at local maxima in the filtered image. Two datasets of 13 temporal bone specimens......When implanting cochlear implants the positions of electrodes have a large impact on the quality of the restored hearing. Due to metal artifacts it is difficult to estimate the precise location in post-operative scans. In this paper we present a method for automatically locating and determining...

  13. Closed Bipolar Electrodes for Spatial Separation of H2 and O2 Evolution during Water Electrolysis and the Development of High-Voltage Fuel Cells.

    Science.gov (United States)

    Goodwin, Sean; Walsh, Darren A

    2017-07-19

    Electrolytic water splitting could potentially provide clean H2 for a future "hydrogen economy". However, as H2 and O2 are produced in close proximity to each other in water electrolyzers, mixing of the gases can occur during electrolysis, with potentially dangerous consequences. Herein, we describe an electrochemical water-splitting cell, in which mixing of the electrogenerated gases is impossible. In our cell, separate H2- and O2-evolving cells are connected electrically by a bipolar electrode in contact with an inexpensive dissolved redox couple (K3Fe(CN)6/K4Fe(CN)6). Electrolytic water splitting occurs in tandem with oxidation/reduction of the K3Fe(CN)6/K4Fe(CN) redox couples in the separate compartments, affording completely spatially separated H2 and O2 evolution. We demonstrate operation of our prototype cell using conventional Pt electrodes for each gas-evolving reaction, as well as using earth-abundant Ni2P electrocatalysts for H2 evolution. Furthermore, we show that our cell can be run in reverse and operate as a H2 fuel cell, releasing the energy stored in the electrogenerated H2 and O2. We also describe how the absence of an ionically conducting electrolyte bridging the H2- and O2-electrode compartments makes it possible to develop H2 fuel cells in which the anode and cathode are at different pH values, thereby increasing the voltage above that of conventional fuel cells. The use of our cell design in electrolyzers could result in dramatically improved safety during operation and the generation of higher-purity H2 than available from conventional electrolysis systems. Our cell could also be readily modified for the electrosynthesis of other chemicals, where mixing of the electrochemical products is undesirable.

  14. Verification of a novel method for tube voltage constancy measurement of orthovoltage x-ray irradiators

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chu; Belley, Matthew D. [Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 and Duke Radiation Dosimetry Laboratory, Duke University Medical Center, Durham, North Carolina 27710 (United States); Chao, Nelson J. [Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710 and Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Dewhirst, Mark W. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Yoshizumi, Terry, E-mail: yoshi003@mc.duke.edu [Duke Radiation Dosimetry Laboratory, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2014-08-15

    Purpose: For orthovoltage x-ray irradiators, the tube voltage is one of the most fundamental system parameters as this directly relates to the dosimetry in radiation biology studies; however, to the best of our knowledge, there is no commercial portable quality assurance (QA) tool to directly test the constancy of the tube voltage greater than 160 kV. The purpose of this study is to establish the Beam Quality Index (BQI), a quantity strongly correlated to the tube voltage, as an alternative parameter for the verification of the tube voltage as part of the QA program of orthovoltage x-ray irradiators. Methods: A multipurpose QA meter and its associated data acquisition software were used to customize the measurement parameters to measure the BQI and collect its time-plot. BQI measurements were performed at 320 kV with four filtration levels on three orthovoltage x-ray irradiators of the same model, one of which had been recently energy-calibrated at the factory. Results: For each of the four filtration levels, the measured BQI values were in good agreement (<5%) between the three irradiators. BQI showed filtration-specificity, possibly due to the difference in beam quality. Conclusions: The BQI has been verified as a feasible alternative for monitoring the constancy of the tube voltage for orthovoltage irradiators. The time-plot of BQI offers information on the behavior of beam energy at different phases of the irradiation time line. In addition, this would provide power supply performance characteristics from initial ramp-up to plateau, and finally, the sharp drop-off at the end of the exposure.

  15. In vivo measurement of carbon dioxide tension with a miniature electrode.

    Science.gov (United States)

    Olievier, C N; Berkenbosch, A; Quanjer, P H

    1978-03-20

    A commercially available catheter type electrode with which PCO2 can be continuously measured in vivo and in vitro gave progressively less accurate results the longer the measuring period was extended. This proved to be due to temperature effects and a change in sensitivity with time. A correction procedure for these effects was developed which was based on two observations. 1. The relationship between temperature and the logarithm of the sensitivity of the electrode-amplifier combination was linear and virtually identical for 9 electrodes: 8% change in sensitivity for a deviation of 1 degree C from the temperature during calibration. 2. The change in sensitivity due to drift of the electrode output is approximately a logarithmic function of time: 1 h after calibration all electrodes exhibited a decreased sensitivity, varying between 0.3 and 16.7%. The drift effect can be dealt with by repeated calibrations, preferably at 1 1/2 h intervals. The adequacy of the correction procedure was assessed in in vivo measurements in cats and dogs. The mean PCO2 difference between the in vivo measurement, corrected for temperature and drift, and samples analyzed with a conventional electrode, was 0.005 kPa (0.04 mm Hg) with a standard deviation of 0.187 kPa (1.39 mm Hg).

  16. Assessment of Carbon/Salt/Adhesive Electrodes for Surface Electromyography Measurements.

    Science.gov (United States)

    Posada-Quintero, Hugo; Rood, Ryan; Burnham, Ken; Pennace, John; Chon, Ki

    2016-01-01

    This paper presents the evaluation of novel electrodes for surface electromyography (sEMG) measurements. The electrodes are based on the mixture of carbon powder, quaternary salt, and viscoelastic polymeric adhesive (carbon/salt/adhesive or simply CSA), which when combined, provide the unique advantages of having longer (theoretically infinite) shelf life and potentially lower cost than Ag/AgCl hydrogel electrodes, consistent with FLEXcon's Patent #8 673 184. The 20 subjects were recruited to collect simultaneous recordings of sEMG signals using Ag/AgCl and CSA electrodes, side-by-side on triceps brachii, tibial anterior muscles, biceps brachii, and quadriceps femoris. Although CSA sEMG electrodes showed higher electrode-skin contact impedance for the frequency range of 4 Hz-2 kHz, no significant differences were found in the signals' amplitude between the two electrodes either during relaxation or contraction stages. Furthermore, correlations of the computed linear envelopes (>0.91), rms value envelopes (>0.91), and power spectral densities (>0.95) of the signals were found to be high between the two media. Detected ON- and OFF-times of contraction were also highly correlated (>0.9) and interchangeable (ON-time: bias = -0.02, variance = 0.11; OFF-time: bias = -0.04, variance = 0.23) between the two media. However, CSA sEMG electrodes exhibited a significantly better response to noise (38.3 ± 10.6 dB versus 32.7 ± 15.6 dB) and motion artifacts (24.1 ± 12.1 dB versus 16.6 ± 8.52 dB), and a significantly lower spectral deformation (1.32 ± 0.2 versus 1.46 ± 0.4). Ag/AgCl electrodes showed a significantly more peaked and sensitive response to EMG amplitude (67.9 ± 13.9 dB versus 65.4 ± 14.6 dB). Given no significant differences in many of the measures described earlier and the fact that CSA electrodes have an infinite shelf-life are potentially lower cost, and are more resistant to motion artifacts, the new electrodes provide an attractive alternative to Ag

  17. A magnetically levitated electrode ionization chamber of the noncontact measurement type

    CERN Document Server

    Kawaguchi, T

    2002-01-01

    A new type of ionization chamber with levitated electrode has been developed. In this ionization chamber, an ion-collection electrode levitates in the air without getting any physical support from the insulator. The electrode is charged by an electrostatic charger without physical contact. The charge of the electrode is read out at a Faraday cage periodically at a given time interval without physical contact. Because its electrode levitates, the ionization chamber produces no background current caused by leaks or piezo current. In addition, as the charging of its electrode and the read-out of its charge are carried out without physical contact, no irregular charge or contact potential difference due to the chattering between electrode and contact point occurs. Through experiments, it was found that this ionization chamber was able to measure the gamma-ray dose such as the environmental radiation with a high degree of sensitivity. The minimum detectable value of ionization current when accumulated for 1 h is a...

  18. Spatial concentration distribution analysis of cells in electrode-multilayered microchannel by dielectric property measurement.

    Science.gov (United States)

    Yao, Jiafeng; Kodera, Tatsuya; Obara, Hiromichi; Sugawara, Michiko; Takei, Masahiro

    2015-07-01

    The spatial concentration distribution of cells in a microchannel is measured by combining the dielectric properties of cells with the specific structure of the electrode-multilayered microchannel. The dielectric properties of cells obtained with the impedance spectroscopy method includes the cell permittivity and dielectric relaxation, which corresponds to the cell concentration and structure. The electrode-multilayered microchannel is constructed by 5 cross-sections, and each cross-section contains 5 electrode-layers embedded with 16 micro electrodes. In the experiment, the dielectric properties of cell suspensions with different volume concentrations are measured with different electrode-combinations corresponding to different electric field distributions. The dielectric relaxations of different cell concentrations are compared and discussed with the Maxwell-Wagner dispersion theory, and the relaxation frequencies are analysed by a cell polarization model established based on the Hanai cell model. Moreover, a significant linear relationship with AC frequency dependency between relative permittivity and cell concentration was found, which provides a promising way to on-line estimate cell concentration in microchannel. Finally, cell distribution in 1 cross-section of the microchannel (X and Y directions) was measured with different electrode-combinations using the dielectric properties of cell suspensions, and cell concentration distribution along the microchannel (Z direction) was visualized at flowing state. The present cell spatial sensing study provides a new approach for 3 dimensional non-invasive online cell sensing for biological industry.

  19. Forward voltage short-pulse technique for measuring high power laser array junction temperature

    Science.gov (United States)

    Meadows, Byron L. (Inventor); Amzajerdian, Frazin (Inventor); Barnes, Bruce W. (Inventor); Baker, Nathaniel R. (Inventor)

    2012-01-01

    The present invention relates to a method of measuring the temperature of the P-N junction within the light-emitting region of a quasi-continuous-wave or pulsed semiconductor laser diode device. A series of relatively short and low current monitor pulses are applied to the laser diode in the period between the main drive current pulses necessary to cause the semiconductor to lase. At the sufficiently low current level of the monitor pulses, the laser diode device does not lase and behaves similar to an electronic diode. The voltage across the laser diode resulting from each of these low current monitor pulses is measured with a high degree of precision. The junction temperature is then determined from the measured junction voltage using their known linear relationship.

  20. Enhancing the performance of high-voltage LiCoMnO4 spinel electrodes by fluorination

    Science.gov (United States)

    Windmüller, Anna; Tsai, Chih-Long; Möller, Sören; Balski, Matthias; Sohn, Yoo Jung; Uhlenbruck, Sven; Guillon, Olivier

    2017-02-01

    With the aim of improving the electrochemical properties of the LiCoMnO4 high-voltage spinel for lithium ion battery applications, LiCoMnO4-yFy (y = 0, 0.05, 0.1) compounds were synthesized by a two-step solid-state reaction at 800 °C. The stoichiometry of the samples was verified by nuclear reaction analysis for the fluorine stoichiometry, inert gas fusion analysis for the oxygen stoichiometry, and inductively coupled plasma optical emission spectroscopy for the cation stoichiometry. X-ray diffraction analysis and scanning electron microscopy revealed increasing phase purity and changing microstructure upon fluorine incorporation. Electrochemical characterizations were carried out in battery test cells using a liquid electrolyte. The samples show poor coulombic efficiency, due to liquid electrolyte decomposition. However, fluorinated spinels demonstrated significantly improved capacities of up to 18% and improved cycling stability of up to 20%, compared to their non-fluorinated counterparts.

  1. Two-point concrete resistivity measurements: interfacial phenomena at the electrode-concrete contact zone

    Science.gov (United States)

    McCarter, W. J.; Taha, H. M.; Suryanto, B.; Starrs, G.

    2015-08-01

    Ac impedance spectroscopy measurements are used to critically examine the end-to-end (two-point) testing technique employed in evaluating the bulk electrical resistivity of concrete. In particular, this paper focusses on the interfacial contact region between the electrode and specimen and the influence of contacting medium and measurement frequency on the impedance response. Two-point and four-point electrode configurations were compared and modelling of the impedance response was undertaken to identify and quantify the contribution of the electrode-specimen contact region on the measured impedance. Measurements are presented in both Bode and Nyquist formats to aid interpretation. Concretes mixes conforming to BSEN206-1 and BS8500-1 were investigated which included concretes containing the supplementary cementitious materials fly ash and ground granulated blast-furnace slag. A measurement protocol is presented for the end-to-end technique in terms of test frequency and electrode-specimen contacting medium in order to minimize electrode-specimen interfacial effect and ensure correct measurement of bulk resistivity.

  2. Iridium Oxide Nanotube Electrodes for Highly Sensitive and Prolonged Intracellular Measurement of Action Potentials

    Science.gov (United States)

    Lin, Ziliang Carter; Xie, Chong; Osakada, Yasuko; Cui, Yi; Cui, Bianxiao

    2014-01-01

    Intracellular recording of action potentials is important to understand electrically-excitable cells. Recently, vertical nanoelectrodes have been developed to achieve highly sensitive, minimally invasive, and large scale intracellular recording. It has been demonstrated that the vertical geometry is crucial for the enhanced signal detection. Here we develop nanoelectrodes made up of nanotubes of iridium oxide. When cardiomyocytes are cultured upon those nanotubes, the cell membrane not only wraps around the vertical tubes but also protrudes deep into the hollow center. We show that this geometry enhances cell-electrode coupling and results in measuring much larger intracellular action potentials. The nanotube electrodes afford much longer intracellular access and are minimally invasive, making it possible to achieve stable recording up to an hour in a single session and more than 8 days of consecutive daily recording. This study suggests that the electrode performance can be significantly improved by optimizing the electrode geometry. PMID:24487777

  3. An easy way to measure accurately the direct magnetoelectric voltage coefficient of thin film devices

    Science.gov (United States)

    Poullain, Gilles; More-Chevalier, Joris; Cibert, Christophe; Bouregba, Rachid

    2017-01-01

    TbxDy1-xFe2/Pt/Pb(Zrx, Ti1-x)O3 thin films were grown on Pt/TiO2/SiO2/Si substrate by multi-target sputtering. The magnetoelectric voltage coefficient αΗΜΕ was determined at room temperature using a lock-in amplifier. By adding, in series in the circuit, a capacitor of the same value as that of the device under test, we were able to demonstrate that the magnetoelectric device behaves as a voltage source. Furthermore, a simple way to subtract the stray voltage arising from the flow of eddy currents in the measurement set-up, is proposed. This allows the easy and accurate determination of the true magnetoelectric voltage coefficient. A large αΗΜΕ of 8.3 V/cm. Oe was thus obtained for a Terfenol-D/Pt/PZT thin film device, without DC magnetic field nor mechanical resonance.

  4. A reference electrode based on polyvinyl butyral (PVB) polymer for decentralized chemical measurements.

    Science.gov (United States)

    Guinovart, Tomàs; Crespo, Gastón A; Rius, F Xavier; Andrade, Francisco J

    2014-04-22

    A new solid-state reference electrode using a polymeric membrane of polyvinyl butyral (PVB), Ag/AgCl and NaCl to be used in decentralized chemical measurements is presented. The electrode is made by drop-casting the membrane cocktail onto a glassy carbon (GC) substrate. A stable potential (less than 1 mV dec(-1)) over a wide range of concentrations for the several chemical species tested is obtained. No significant influence to changes in redox potential, light and pH are observed. The response of this novel electrode shows good correlation when compared with a conventional double-junction reference electrode. Also good long-term stability (90±33 μV/h) and a lifetime of approximately 4 months are obtained. Aspects related to the working mechanisms are discussed. Atomic Force Microscopy (AFM) studies reveal the presence of nanopores and channels on the surface, and electrochemical impedance spectroscopy (EIS) of optimized electrodes show low bulk resistances, usually in the kΩ range, suggesting that a nanoporous polymeric structure is formed in the interface with the solution. Future applications of this electrode as a disposable device for decentralized measurements are discussed. Examples of the utilization on wearable substrates (tattoos, fabrics, etc) are provided.

  5. Advanced Ring-Shaped Microelectrode Assay Combined with Small Rectangular Electrode for Quasi-In vivo Measurement of Cell-to-Cell Conductance in Cardiomyocyte Network

    Science.gov (United States)

    Nomura, Fumimasa; Kaneko, Tomoyuki; Hamada, Tomoyo; Hattori, Akihiro; Yasuda, Kenji

    2013-06-01

    To predict the risk of fatal arrhythmia induced by cardiotoxicity in the highly complex human heart system, we have developed a novel quasi-in vivo electrophysiological measurement assay, which combines a ring-shaped human cardiomyocyte network and a set of two electrodes that form a large single ring-shaped electrode for the direct measurement of irregular cell-to-cell conductance occurrence in a cardiomyocyte network, and a small rectangular microelectrode for forced pacing of cardiomyocyte beating and for acquiring the field potential waveforms of cardiomyocytes. The advantages of this assay are as follows. The electrophysiological signals of cardiomyocytes in the ring-shaped network are superimposed directly on a single loop-shaped electrode, in which the information of asynchronous behavior of cell-to-cell conductance are included, without requiring a set of huge numbers of microelectrode arrays, a set of fast data conversion circuits, or a complex analysis in a computer. Another advantage is that the small rectangular electrode can control the position and timing of forced beating in a ring-shaped human induced pluripotent stem cell (hiPS)-derived cardiomyocyte network and can also acquire the field potentials of cardiomyocytes. First, we constructed the human iPS-derived cardiomyocyte ring-shaped network on the set of two electrodes, and acquired the field potential signals of particular cardiomyocytes in the ring-shaped cardiomyocyte network during simultaneous acquisition of the superimposed signals of whole-cardiomyocyte networks representing cell-to-cell conduction. Using the small rectangular electrode, we have also evaluated the response of the cell network to electrical stimulation. The mean and SD of the minimum stimulation voltage required for pacing (VMin) at the small rectangular electrode was 166+/-74 mV, which is the same as the magnitude of amplitude for the pacing using the ring-shaped electrode (179+/-33 mV). The results showed that the

  6. A high-precision network analyzer system for the measurement of the electrode impedance of both stationary and non-stationary electrode, with special attention to the dropping mercury electrode

    NARCIS (Netherlands)

    Bongenaar, C.P.M.; Sluyters-Rehbach, M.; Sluyters, J.H.

    1980-01-01

    A largely automatic instrument for the measurement of the admittance of a galvanic cell is described. During a measurement the frequency of the alternating voltage and the dc voltage are scanned stepwise in a programmed sequence. A high precision has been obtained by applying a programmed correction

  7. Time dependent capacitance voltage measurements on Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Adler, Tobias; Klein, Andreas [Darmstadt University of Technology, Institute of Materials Science, Petersenstrasse 32, D-64287 Darmstadt (Germany); Witte, Wolfram; Hariskos, Dimitrios [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Industriestrasse 6, D-70565 Stuttgart (Germany)

    2011-07-01

    Capacitance Voltage (C-V) measurements are widely used to determine the doping density of semiconductor interfaces in dependence on the width of the space charge layer. In Cu(In,Ga)Se{sub 2} (CIGS) solar cells we observe a time dependent capacitance signal, which can be explained by different models like filling and emptying of electronic (metastable) defect states or by the diffusion of copper ions. The observed capacitance transients are compared to the different models.

  8. An investigation of breakdown voltage in AMTECs

    Science.gov (United States)

    Momozaki, Yoichi; El-Genk, Mohamed S.

    2002-01-01

    Experiments are conducted to investigate the DC electrical breakdown voltage in cesium vapor between two planner molybdenum electrodes, 1.6 cm in diameter, separated by a 0.5 mm gap, and relate the results to the potential electrical breakdown on the cathode side of Alkali Metal Thermal-to-Electric Converters (AMTECs). In the first set of experiments, in which the electrodes are kept at 560 and 650 K, while varying the cesium pressure from 0.71 to 29 Pa, when the cooler electrode is positively biased, breakdown occurs at ~500 V, but at 700 V when the cooler electrode is negatively biased. In the second set of experiments, in which the electrodes are held at 625 and 1100 K and the cesium pressure varied from 1.7 to 235 Pa, when the cooler electrode is positively biased, breakdown voltage is <4 V, but in excess of 400 V when the cooler electrode is negatively biased. Since the first ionization potential and the ionization rate constant of cesium are lower and higher, respectively, than for the sodium (5.14 V) and potassium (4.34 V) vapors in AMTECs, the DC electrical breakdown voltage in an AMTEC is expected to be higher than measured in this work for cesium vapor. .

  9. ELABORATION OF HIGH-VOLTAGE PULSE INSTALLATIONS AND PROVIDING THEIR OPERATION PROTECTIVE MEASURES

    Directory of Open Access Journals (Sweden)

    А. М. Hashimov

    2016-01-01

    Full Text Available The article presents design engineering methods for the high-voltage pulse installations of technological purpose for disinfection of drinking water, sewage, and edible liquids by high field micro- and nanosecond pulsing exposure. Designing potentialities are considered of the principal elements of the high-voltage part and the discharge circuit of the installations towards assuring the best efficient on-load utilization of the source energy and safe operation of the high-voltage equipment. The study shows that for disinfection of drinking water and sewage it is expedient to apply microsecond pulse actions causing the electrohydraulic effect in aqueous media with associated complex of physical processes (ultraviolet emission, generation of ozone and atomic oxygen, mechanical compression waves, etc. having detrimental effect on life activity of the microorganisms. In case of disinfecting edible liquids it is recommended to use the nanosecond pulses capable of straight permeating the biological cell nucleus, inactivating it. Meanwhile, the nutritive and biological values of the foodstuffs are saved and their organoleptic properties are improved. It is noted that in elaboration process of high-frequency pulse installations special consideration should be given to issues of the operating personnel safety discipline and securing conditions for the entire installation uninterrupted performance. With this objective in view the necessary requirements should be fulfilled on shielding the high- and low-voltage installation parts against high-frequency electromagnetic emissions registered by special differential sensors. Simultaneously, the abatement measures should be applied on the high-voltage equipment operational noise level. The authors offer a technique for noise abatement to admissible levels (lower than 80 dB A by means of coating the inside surface with shielded enclosure of densely-packed abutting sheets of porous electro-acoustic insulating

  10. SPEAR-1: An experiment to measure current collection in the ionosphere by high voltage biased conductors

    Science.gov (United States)

    Raitt, W. John; Myers, Neil B.; Roberts, Jon A.; Thompson, D. C.

    1990-01-01

    An experiment is described in which a high electrical potential difference, up to 45 kV, was applied between deployed conducting spheres and a sounding rocket in the ionosphere. Measurements were made of the applied voltage and the resulting currents for each of 24 applications of different high potentials. In addition, diagnostic measurements of optical emissions in the vicinity of the spheres, energetic particle flow to the sounding rocket, dc electric field and wave data were made. The ambient plasma and neutral environments were measured by a Langmuir probe and a cold cathode neutral ionization gauge, respectively. The payload is described and examples of the measured current and voltage characteristics are presented. The characteristics of the measured currents are discussed in terms of the diagnostic measurements and the in-situ measurements of the vehicle environment. In general, it was found that the currents observed were at a level typical of magnetically limited currents from the ionospheric plasma for potentials less than 12 kV, and slightly higher for larger potentials. However, due to the failure to expose the plasma contactor, the vehicle sheath modified the sphere sheaths and made comparisons with the analytic models of Langmuir-Blodgett and Parker-Murphy less meaningful. Examples of localized enhancements of ambient gas density resulting from the operation of the attitude control system thrusters (cold nitrogen) were obtained. Current measurements and optical data indicated localized discharges due to enhanced gas density that reduced the vehicle-ionosphere impedance.

  11. Direct voltage measurements using bulk acoustic wave sensing in LiNbO3

    Science.gov (United States)

    Patel, Nishant Bhupendra

    Accurate (impedance effects that can distort the pulse shape, and pickup of extraneous signals resulting from electromagnetic interference effects. A piezoelectric crystal-based bulk acoustic wave sensor using lithium niobate (LiNbO3) that has applications to metrology, research, and power metering was developed to overcome these measurement issues with the factors of scalability, ease of use, and compactness in mind. A Y+36° cut LiNbO3crystal was coupled to two acoustic transducers, where direct current (DC) voltages ranging from 128--1100 V were applied transversely to the crystal. An acoustic wave was used to interrogate the crystal before, during, and after voltage application. Both single and multiple pass measurements were performed and compared to linear piezoelectric theory. A comparison study between Y+36° and 0° X-cut LiNbO3 was performed to evaluate the influence of crystal cut on acoustic propagation. The study was extended to applying alternating current (AC), and pulsed voltages. The measured DC data was compared to a 1-D impedance matrix model that was based on a three port circuit with voltage-induced strain effects inputted as a model parameter. An uncertainty budget was carried out for both crystal cuts and compared. Environmental effects such as pressure and temperature were also measured to determine their influence on the sensor under ambient conditions. Published literature regarding material constants, such as elastic constants and piezoelectric constants, for LiNbO3 do not account for the influence of an electric field. In light of this, measurements of the acoustic velocities and material constants under the presence of a DC electric field were performed up to 896 V. This information was used to develop an uncertainty analysis for the determination of stress-charge form piezoelectric constants e15 and e22. All measured and calculated values were input into a Monte Carlo simulation to determine the error of the strain-charge form

  12. Complete electrode model in EEG: relationship and differences to the point electrode model

    Science.gov (United States)

    Pursiainen, S.; Lucka, F.; Wolters, C. H.

    2012-02-01

    In electroencephalography (EEG) source analysis, a primary current density generated by the neural activity of the brain is reconstructed from external electrode voltage measurements. This paper focuses on accurate and effective simulations of EEG through the complete electrode model (CEM). The CEM allows for the incorporation of the electrode size, shape and effective contact impedance into the forward simulation. Both neural currents in the brain and shunting currents between the electrodes and the skin can affect the measured voltages in the CEM. The goal of this study was to investigate the CEM by comparing it with the point electrode model (PEM), which is the current standard electrode model for EEG. We used a three-dimensional, realistic and high-resolution finite element head model as the reference computational domain in the comparison. The PEM could be formulated as a limit of the CEM, in which the effective impedance of each electrode goes to infinity and the size tends to zero. Numerical results concerning the forward and inverse errors and electrode voltage strengths with different impedances and electrode sizes are presented. Based on the results obtained, limits for extremely high and low impedance values of the shunting currents are suggested.

  13. Simple light guide for measuring irradiance in an aqueous oxygen electrode chamber.

    Science.gov (United States)

    Vogtschaller, Jeff; Wise, Robert

    2004-01-01

    The light-dependent reactions of photosynthesis are often measured with Clark-type oxygen electrodes yet the irradiance level inside aqueous oxygen electrode reaction vessels is seldom reported due to the difficulty of measuring light inside a small volume chamber. We describe a simple light guide terminating in a 90 degrees prism that can be inserted into a reaction vessel. Incoming irradiation is directed to a commercially available quantum sensor positioned at the other end of the light guide. Both materials for and construction of the device are inexpensive.

  14. Analysis of SOFCs Using Reference Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Finklea, H.; Chen, X.; Gerdes, K.; Pakalapati, S.; Celik, I.

    2013-01-01

    Reference electrodes are frequently applied to isolate the performance of one electrode in a solid oxide fuel cell. However, reference electrode simulations raise doubt to veracity of data collected using reference electrodes. The simulations predict that the reported performance for the one electrode will frequently contain performance of both electrodes. Nonetheless, recent reports persistently treat data so collected as ideally isolated. This work confirms the predictions of the reference electrode simulations on two SOFC designs, and to provides a method of validating the data measured in the 3-electrode configuration. Validation is based on the assumption that a change in gas composition to one electrode does not affect the impedance of the other electrode at open circuit voltage. This assumption is supported by a full physics simulation of the SOFC. Three configurations of reference electrode and cell design are experimentally examined using various gas flows and two temperatures. Impedance data are subjected to deconvolution analysis and equivalent circuit fitting and approximate polarization resistances of the cathode and anode are determined. The results demonstrate that the utility of reference electrodes is limited and often wholly inappropriate. Reported impedances and single electrode polarization values must be scrutinized on this basis.

  15. Mathematical modeling and measurement of electric fields of electrode-based through-the-earth (TTE) communication

    Science.gov (United States)

    Yan, Lincan; Zhou, Chenming; Reyes, Miguel; Whisner, Bruce; Damiano, Nicholas

    2017-06-01

    There are two types of through-the-earth (TTE) wireless communication in the mining industry: magnetic loop TTE and electrode-based (or linear) TTE. While the magnetic loop systems send signal through magnetic fields, the transmitter of an electrode-based TTE system sends signal directly through the mine overburden by driving an extremely low frequency (ELF) or ultralow frequency (ULF) AC current into the earth. The receiver at the other end (underground or surface) detects the resultant current and receives it as a voltage. A wireless communication link between surface and underground is then established. For electrode-based TTE communications, the signal is transmitted through the established electric field and is received as a voltage detected at the receiver. It is important to understand the electric field distribution within the mine overburden for the purpose of designing and improving the performance of the electrode-based TTE systems. In this paper, a complete explicit solution for all three electric field components for the electrode-based TTE communication was developed. An experiment was conducted using a prototype electrode-based TTE system developed by National Institute for Occupational Safety and Health. The mathematical model was then compared and validated with test data. A reasonable agreement was found between them.

  16. A reference electrode based on polyvinyl butyral (PVB) polymer for decentralized chemical measurements

    Energy Technology Data Exchange (ETDEWEB)

    Guinovart, Tomàs [Departament de Química Orgànica i Química Analítica, Universitat Rovira i Virgili, Carrer Marcellí Domingo s/n 43007 Tarragona (Spain); Crespo, Gastón A. [Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva (Switzerland); Rius, F. Xavier [Departament de Química Orgànica i Química Analítica, Universitat Rovira i Virgili, Carrer Marcellí Domingo s/n 43007 Tarragona (Spain); Andrade, Francisco J., E-mail: franciscojavier.andrade@urv.cat [Departament de Química Orgànica i Química Analítica, Universitat Rovira i Virgili, Carrer Marcellí Domingo s/n 43007 Tarragona (Spain)

    2014-04-01

    Highlights: • A disposable solid-contact reference electrode for potentiometry is presented. • The device shows unsensitivity to most ions, redox potential and light. • Low-cost and good stability, ideal to build disposable potentiometric sensors. • Nanopores formed in the membrane control the flux of ions with the solution. Abstract: A new solid-state reference electrode using a polymeric membrane of polyvinyl butyral (PVB), Ag/AgCl and NaCl to be used in decentralized chemical measurements is presented. The electrode is made by drop-casting the membrane cocktail onto a glassy carbon (GC) substrate. A stable potential (less than 1 mV dec⁻¹ over a wide range of concentrations for the several chemical species tested is obtained. No significant influence to changes in redox potential, light and pH are observed. The response of this novel electrode shows good correlation when compared with a conventional double-junction reference electrode. Also good long-term stability (90 ± 33 μV/h) and a lifetime of approximately 4 months are obtained. Aspects related to the working mechanisms are discussed. Atomic Force Microscopy (AFM) studies reveal the presence of nanopores and channels on the surface, and electrochemical impedance spectroscopy (EIS) of optimized electrodes show low bulk resistances, usually in the kΩ range, suggesting that a nanoporous polymeric structure is formed in the interface with the solution. Future applications of this electrode as a disposable device for decentralized measurements are discussed. Examples of the utilization on wearable substrates (tattoos, fabrics, etc) are provided.

  17. Pressure and Arc Voltage Measurement in a 252 kV SF6 Puffer Circuit Breaker

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jianying; GUO Yujing; ZHANG Hao

    2016-01-01

    The pressure distribution in an arcing chamber is critically important for the SF6 puffer circuit breaker design.In this paper,the pressure variation of four locations in the nozzle was measured by piezoresistive and fiber optical pressure sensors at two current levels of 10 kA and 50 kA.An arc voltage measurement was also taken.The results demonstrate that using either type of sensor with a connecting tube is able to detect the fast pressure variation in circuit breakers,however the possible distortion and delay to the pressure transient caused by the tube need further study.

  18. Pressure and Arc Voltage Measurement in a 252 kV SF6 Puffer Circuit Breaker

    Science.gov (United States)

    Zhong, Jianying; Guo, Yujing; Zhang, Hao

    2016-05-01

    The pressure distribution in an arcing chamber is critically important for the SF6 puffer circuit breaker design. In this paper, the pressure variation of four locations in the nozzle was measured by piezoresistive and fiber optical pressure sensors at two current levels of 10 kA and 50 kA. An arc voltage measurement was also taken. The results demonstrate that using either type of sensor with a connecting tube is able to detect the fast pressure variation in circuit breakers, however the possible distortion and delay to the pressure transient caused by the tube need further study.

  19. Cooling of electrically insulated high voltage electrodes down to 30 mK Kühlung von elektrisch isolierten Hochspannungselektroden bis 30 mK

    CERN Document Server

    Eisel, Thomas; Bremer, J

    2011-01-01

    The Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEGIS) at the European Organization for Nuclear Research (CERN) is an experiment investigating the influence of earth’s gravitational force upon antimatter. To perform precise measurements the antimatter needs to be cooled to a temperature of 100 mK. This will be done in a Penning trap, formed by several electrodes, which are charged with several kV and have to be individually electrically insulated. The trap is thermally linked to a mixing chamber of a 3He-4He dilution refrigerator. Two link designs are examined, the Rod design and the Sandwich design. The Rod design electrically connects a single electrode with a heat exchanger, immersed in the helium of the mixing chamber, by a copper pin. An alumina ring and the helium electrically insulate the Rod design. The Sandwich uses an electrically insulating sapphire plate sandwiched between the electrode and the mixing chamber. Indium layers on the sapphire plate are applied to improve the ther...

  20. Development of a Compensation Scheme for a Measurement Voltage Transformer Using the Hysteresis Characteristics of a Core

    Directory of Open Access Journals (Sweden)

    Hyewon Lee

    2015-04-01

    Full Text Available This paper describes the design, evaluation, and implementation of a compensation scheme for a measurement voltage transformer (VT using the hysteresis characteristics of the core. The error of a VT is caused by the primary winding voltage and secondary winding voltage. The latter depends on the secondary current, whereas the former depends on the primary current, which is an aggregate of the exciting and secondary currents. The secondary current is obtained directly from the secondary voltage and is used to obtain the voltage across the secondary winding. For the primary current, the exciting current is decomposed into two components: core-loss and magnetizing currents. The magnetizing current is obtained by the flux-magnetizing current curve instead of the hysteresis loop to minimize the required loops for compensation. The core-loss current is obtained by dividing the primary induced voltage by the core-loss resistance. Finally, the estimated voltages across the primary and secondary windings are added to the measured secondary voltage for compensation. The scheme can significantly improve the accuracy of a VT. The results of the performance of compensator are shown in the experimental test. The accuracy of the measurement VT improves from 1.0C class to 0.1C class. The scheme can help to significantly reduce the required core cross section of a measurement VT in an electrical energy system.

  1. 18650 Li-ion cells with reference electrode and in situ characterization of electrodes

    Science.gov (United States)

    Nagasubramanian, G.; Doughty, D. H.

    At Sandia National Laboratories, we have built 18650 Li-ion cells with Li reference electrode for in situ characterization of electrodes including impedance and other electrochemical properties. At a 200 mA (˜C/5 rate) discharge, the cell gave ˜900 mAh. Impedance measurements indicate that the anode dominates the cell impedance. For example, at 0 °C, the anode and cathode impedances at 10 mHz were around 149 and 53 mΩ, respectively, and the total cell impedance at 10 mHz was ˜203 mΩ. The three-electrode configuration also permits measurement of individual electrode voltages during charge and discharge. During discharge, while the cell voltage drops from 4.1 to 3 V, the cathode and the anode voltages change from 4.1 to 3.7 and from ˜0 to 0.7 V, respectively. During charge, the cathode and anode voltages trace back to their initial values before discharging. The voltage swing for the anode is higher than that for the cathode. This also indicates that the impedance for the anode is higher than for the cathode. Pulse measurements on the cells indicate the voltage drop of the full-cell is equal to the sum of the anode and cathode voltage drops for a 2 A discharge pulse.

  2. Voltage biasing, cyclic voltammetry, & electrical impedance spectroscopy for neural interfaces.

    Science.gov (United States)

    Wilks, Seth J; Richner, Tom J; Brodnick, Sarah K; Kipke, Daryl R; Williams, Justin C; Otto, Kevin J

    2012-02-24

    Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measure properties of the electrode-tissue interface without additional invasive procedures, and can be used to monitor electrode performance over the long term. EIS measures electrical impedance at multiple frequencies, and increases in impedance indicate increased glial scar formation around the device, while cyclic voltammetry measures the charge carrying capacity of the electrode, and indicates how charge is transferred at different voltage levels. As implanted electrodes age, EIS and CV data change, and electrode sites that previously recorded spiking neurons often exhibit significantly lower efficacy for neural recording. The application of a brief voltage pulse to implanted electrode arrays, known as rejuvenation, can bring back spiking activity on otherwise silent electrode sites for a period of time. Rejuvenation alters EIS and CV, and can be monitored by these complementary methods. Typically, EIS is measured daily as an indication of the tissue response at the electrode site. If spikes are absent in a channel that previously had spikes, then CV is used to determine the charge carrying capacity of the electrode site, and rejuvenation can be applied to improve the interface efficacy. CV and EIS are then repeated to check the changes at the electrode-tissue interface, and neural recordings are collected. The overall goal of rejuvenation is to extend the functional lifetime of implanted arrays.

  3. An instrumentation amplifier as a front-end for a four-electrode bioimpedance measurement.

    Science.gov (United States)

    Zagar, T; Krizaj, D

    2007-08-01

    The performance of a monolithic instrumentation amplifier used as an interface for a four-electrode bioimpedance measurement is examined with a commercially available impedance meter based on an auto-balancing bridge. The errors due to particularities in the input stage of the impedance meter, when used without a front-end, were several orders of magnitude higher than the measured quantity. The analysis was performed on an electrical circuit model of the skin and electrodes over a frequency range of 20 Hz to 1 MHz. The achieved accuracy with balanced electrode impedances for the frequencies up to 100 kHz can be below 0.2% for impedance magnitude and 0.1 degrees for impedance phase, which is within the specified basic accuracy range of the LCR-meter used for the measurements. At frequencies above 100 kHz the errors are increasing and are higher than the LCR-meter's basic accuracy. This study indicates that use of an instrumentation amplifier as a front-end with the particular LCR-meter can significantly improve the measurement accuracy of the four-electrode bioimpedance measurement at low frequencies.

  4. Analysis of the match problem of a capacitive voltage divider with a long measurement cable

    Science.gov (United States)

    Yu, Bin-Xiong; Li, Rui; Su, Jian-Cang; Zhao, Liang; Zhang, Yu; Zheng, Lei; Zeng, Bo; Cheng, Jie; Gao, Peng-Cheng; Qiu, Xu-Dong; Xu, Xu-dong

    2017-09-01

    Research is carried out on the basis of the traditional two-end matched circuit of a capacitive voltage divider with a long measurement cable. Transmission progress in the circuit is analyzed theoretically. A match condition of the circuit is acquired, which requires that the circuit satisfies two conditions: (1) the measurement error should be small for a pulse with a duration of less than twice the delay time of the measurement cable; (2) the initial division ratio and the stable division ratio of the circuit are the same. Two matched methods of the circuit are acquired, including the first-order matched method and the second-order matched method. Numerical simulations are carried out. According to the simulation results, the relative errors of the circuits with a cable of 20 m are less than 1.5%, obtained by using both match methods for measurement of rectangular pulses with rise and fall times of 5 ns. An improved circuit is presented, which is suitable for any situation where the low-voltage capacitance of the capacitive divider is even smaller than the capaictance of the measurement cable. A verification experment is carried out, and the test result confirms the simulation result.

  5. Work function measurement of multilayer electrodes using Kelvin probe force microscopy

    Science.gov (United States)

    Peres, L.; Bou, A.; Cornille, C.; Barakel, D.; Torchio, P.

    2017-04-01

    The workfunction of dielectric|metal|dielectric transparent and conductive electrodes, promising candidates for replacing ITO in thin film solar cells, is measured by Kelvin probe force microscopy (KPFM). Measurement on commercial ITO gives a workfunction of 4.74 eV, which is in agreement with the values reported in the literature. Measurements are then performed on optically optimised multilayer electrodes fabricated on glass by e-beam evaporation, using three different dielectrics. For TiO2(37 nm)|Ag(13 nm)|TiO2(42 nm), SnO x (45 nm)|Ag(10 nm)|SnO x (45 nm), and ZnS(47 nm)|Ag(12 nm)|ZnS(42 nm), workfunctions of 4.83 eV, 4.75 eV, and 4.48 eV are measured respectively. These values suggest that these transparent and conductive electrodes are well adapted to extract photo-generated charge carriers in photovoltaic devices in which ITO is normally used. Furthermore, the KPFM technique proves to be an efficient and relatively fast way to determine the work function values of such electrodes.

  6. Secondary Ionization Coefficient of Dielectric Electrode

    Science.gov (United States)

    Kashiwagi, Yasuhide; Suzuki, Susumu; Itoh, Haruo

    Experiments for observations and stabilization of discharge paths in several electrode systems are carried out aiming at precise measurement of the secondary ionization coefficient γ of MgO film electrode. The discharge chamber is filled with Ar gas. The waveforms of the applied voltage between the electrodes and the discharge current are measured with visual observation of the discharge light. Two MgO coated electrodes are placed so that they are facing each other. For these MgO electrodes, the discharge paths take a detour, not the shortest distance. Smaller prebreakdown current pulses are observed before the breakdown. After breakdown, discontinuous discharge current is observed. Therefore, it is prepared a glass tube surrounding the discharge area. As the result, the discharge paths take a straight perpendicular for the electrode surface, and the discharge is stabilized.

  7. The improved interleaved voltage measurement method for series connected battery packs

    Science.gov (United States)

    Xia, Bing; Nguyen, Truong; Yang, Jufeng; Mi, Chris

    2016-12-01

    This paper proposes an improved interleaved voltage measurement method for battery packs in electric vehicles, which can distinguish between the sensor fault and cell fault without hardware or software redundancy. The coprime constraint in the basic interleaved measurement method is revisited with a new proof, and a graphical interpretation is introduced to visualize the constraint. Based on that, an improved measurement topology is developed to remove the coprime constraint which enables broader application. Moreover, the hardware implementation of the improved method is discussed based on cost and circuit design. The associated improvement in noise performance is mathematically formulated, and the noise limit and trend of the interleaved measurement method are derived. Simulation results match the noise analysis and experiments validate the broader application of the improved method.

  8. A Primary and Backup Protection Algorithm based on Voltage and Current Measurements for HVDC Grids

    OpenAIRE

    Abedrabbo, Mudar; Van Hertem, Dirk

    2016-01-01

    DC grids are susceptible to DC side faults, which lead to a rapid rise of the DC side currents. DC side faults should be detected in a very short time before fault currents cause damage to the system or equipment, e.g., exceed the maximum interruptible limits of DC circuit breaker. This paper presents a primary and backup protective data-based algorithm. The proposed algorithm depends on the local voltage and current measurements to detect and identify various kinds of faults in the HVDC grid...

  9. Curved Microneedle Array-Based sEMG Electrode for Robust Long-Term Measurements and High Selectivity.

    Science.gov (United States)

    Kim, Minjae; Kim, Taewan; Kim, Dong Sung; Chung, Wan Kyun

    2015-07-06

    Surface electromyography is widely used in many fields to infer human intention. However, conventional electrodes are not appropriate for long-term measurements and are easily influenced by the environment, so the range of applications of sEMG is limited. In this paper, we propose a flexible band-integrated, curved microneedle array electrode for robust long-term measurements, high selectivity, and easy applicability. Signal quality, in terms of long-term usability and sensitivity to perspiration, was investigated. Its motion-discriminating performance was also evaluated. The results show that the proposed electrode is robust to perspiration and can maintain a high-quality measuring ability for over 8 h. The proposed electrode also has high selectivity for motion compared with a commercial wet electrode and dry electrode.

  10. Curved Microneedle Array-Based sEMG Electrode for Robust Long-Term Measurements and High Selectivity

    Directory of Open Access Journals (Sweden)

    Minjae Kim

    2015-07-01

    Full Text Available Surface electromyography is widely used in many fields to infer human intention. However, conventional electrodes are not appropriate for long-term measurements and are easily influenced by the environment, so the range of applications of sEMG is limited. In this paper, we propose a flexible band-integrated, curved microneedle array electrode for robust long-term measurements, high selectivity, and easy applicability. Signal quality, in terms of long-term usability and sensitivity to perspiration, was investigated. Its motion-discriminating performance was also evaluated. The results show that the proposed electrode is robust to perspiration and can maintain a high-quality measuring ability for over 8 h. The proposed electrode also has high selectivity for motion compared with a commercial wet electrode and dry electrode.

  11. Radio frequency current-voltage probe for impedance and power measurements in multi-frequency unmatched loads

    Science.gov (United States)

    Lafleur, T.; Delattre, P. A.; Booth, J. P.; Johnson, E. V.; Dine, S.

    2013-01-01

    A broad-band, inline current-voltage probe, with a characteristic impedance of 50 Ω, is presented for the measurement of voltage and current waveforms, impedance, and power in rf systems. The probe, which uses capacitive and inductive sensors to determine the voltage and current, respectively, can be used for the measurement of single or multi-frequency signals into both matched and unmatched loads, over a frequency range of about 1-100 MHz. The probe calibration and impedance/power measurement technique are described in detail, and the calibrated probe results are compared with those obtained from a vector network analyzer and other commercial power meters. Use of the probe is demonstrated with the measurement of power into an unmatched capacitively coupled plasma excited by multi-frequency tailored voltage waveforms.

  12. Radio frequency current-voltage probe for impedance and power measurements in multi-frequency unmatched loads.

    Science.gov (United States)

    Lafleur, T; Delattre, P A; Booth, J P; Johnson, E V; Dine, S

    2013-01-01

    A broad-band, inline current-voltage probe, with a characteristic impedance of 50 Ω, is presented for the measurement of voltage and current waveforms, impedance, and power in rf systems. The probe, which uses capacitive and inductive sensors to determine the voltage and current, respectively, can be used for the measurement of single or multi-frequency signals into both matched and unmatched loads, over a frequency range of about 1-100 MHz. The probe calibration and impedance/power measurement technique are described in detail, and the calibrated probe results are compared with those obtained from a vector network analyzer and other commercial power meters. Use of the probe is demonstrated with the measurement of power into an unmatched capacitively coupled plasma excited by multi-frequency tailored voltage waveforms.

  13. Understanding Voltage Decay in Lithium-Rich Manganese-Based Layered Cathode Materials by Limiting Cutoff Voltage.

    Science.gov (United States)

    Yang, Jingsong; Xiao, Lifen; He, Wei; Fan, Jiangwei; Chen, Zhongxue; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-07-27

    The effect of the cutoff voltages on the working voltage decay and cyclability of the lithium-rich manganese-based layered cathode (LRMO) was investigated by electrochemical measurements, electrochemical impedance spectroscopy, ex situ X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy line scan technologies. It was found that both lower (2.0 V) and upper (4.8 V) cutoff voltages cause severe voltage decay with cycling due to formation of the spinel phase and migration of the transition metals inside the particles. Appropriate cutoff voltage between 2.8 and 4.4 V can effectively inhibit structural variation as the electrode demonstrates 92% capacity retention and indiscernible working voltage decay over 430 cycles. The results also show that phase transformation not only on high charge voltage but also on low discharge voltage should be addressed to obtain highly stable LRMO materials.

  14. Comparative study of electrostatic sensors with circular and probe electrodes for velocity measurement of pulverised coal

    Institute of Scientific and Technical Information of China (English)

    Shao Jiaqing; Krabicka Jan; Yah Yong

    2007-01-01

    This paper presents recent progress on the velocity measurement of pulverised coal in pneumatic pipelines using electrostatic sensors in combination with correlation signal processing techniques. A comparative study of electrostatic sensors with circular and probe electrodes was conducted on a 94 mm bore horizontal pipeline in a 4 MW furnace. The advantages and limitations of both sensors are discussed. Experimental results demonstrate that both sensors are capable of providing pulverised coal velocity measurement with excellent repeatability and dynamic response.

  15. In-situ pH Measurement at the Electrode/Solution Interface

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper a pH microprobe technique was developed to measure in-situ the pH value at the electrode/solution interface. Iridium oxide was used as a pH sensitive material with good response behavior in the measured solutions. The experimental results indicated that the interfacial pH increased with the applied potential, first jumped to a maximum, then slowly decreased at the controlled potential during the electrodeposition process of functional ceramics.

  16. Development of standard test methods for evaluating defibrillation recovery characteristics of disposable ECG electrodes.

    Science.gov (United States)

    Schoenberg, A A; Booth, H E; Lyon, P C

    1979-01-01

    A clinically relevant test for the measurement of defibrillation overload recovery of prefilled disposable ECG electrodes was developed and is proposed for use in an ECG electrode standard under development by AAMI. Defibrillation overload voltages and currents, as well as electrode polarization recovery voltages, were first measured in animal tests on 12 types of electrodes to allow correlation with various bench tests using a capacitor discharge at 10, 200, or 1000 V. Current overloads absorbed by the electrodes under worst conditions in animal tests were in the range of 2 percent of the defibrillation current flowing through the chest. These overloads were absorbed by most Ag-AgCl electrodes without excessive polarization. However, stainless steel, brass, and tin electrodes tended to polarize to levels that would saturate many ECG monitors. A standard bench test using a 200-V 10-muF capacitor was recommended for inclusion in the AAMI standard to determine whether electrodes are acceptable for use during defibrillation.

  17. Continuous and selective measurement of oxytocin and vasopressin using boron-doped diamond electrodes

    Science.gov (United States)

    Asai, Kai; Ivandini, Tribidasari A.; Einaga, Yasuaki

    2016-09-01

    The electrochemical detection of oxytocin using boron-doped diamond (BDD) electrodes was studied. Cyclic voltammetry of oxytocin in a phosphate buffer solution exhibits an oxidation peak at +0.7 V (vs. Ag/AgCl), which is attributable to oxidation of the phenolic group in the tyrosyl moiety. Furthermore, the linearity of the current peaks obtained in flow injection analysis (FIA) using BDD microelectrodes over the oxytocin concentration range from 0.1 to 10.0 μM with a detection limit of 50 nM (S/N = 3) was high (R2 = 0.995). Although the voltammograms of oxytocin and vasopressin observed with an as-deposited BDD electrode, as well as with a cathodically-reduced BDD electrode, were similar, a clear distinction was observed with anodically-oxidized BDD electrodes due to the attractive interaction between vasopressin and the oxidized BDD surface. By means of this distinction, selective measurements using chronoamperometry combined with flow injection analysis at an optimized potential were demonstrated, indicating the possibility of making selective in situ or in vivo measurements of oxytocin.

  18. Continuous and selective measurement of oxytocin and vasopressin using boron-doped diamond electrodes

    Science.gov (United States)

    Asai, Kai; Ivandini, Tribidasari A.; Einaga, Yasuaki

    2016-01-01

    The electrochemical detection of oxytocin using boron-doped diamond (BDD) electrodes was studied. Cyclic voltammetry of oxytocin in a phosphate buffer solution exhibits an oxidation peak at +0.7 V (vs. Ag/AgCl), which is attributable to oxidation of the phenolic group in the tyrosyl moiety. Furthermore, the linearity of the current peaks obtained in flow injection analysis (FIA) using BDD microelectrodes over the oxytocin concentration range from 0.1 to 10.0 μM with a detection limit of 50 nM (S/N = 3) was high (R2 = 0.995). Although the voltammograms of oxytocin and vasopressin observed with an as-deposited BDD electrode, as well as with a cathodically-reduced BDD electrode, were similar, a clear distinction was observed with anodically-oxidized BDD electrodes due to the attractive interaction between vasopressin and the oxidized BDD surface. By means of this distinction, selective measurements using chronoamperometry combined with flow injection analysis at an optimized potential were demonstrated, indicating the possibility of making selective in situ or in vivo measurements of oxytocin. PMID:27599852

  19. Membrane potential measurements of isolated neurons using a voltage-sensitive dye.

    Directory of Open Access Journals (Sweden)

    Richard Fairless

    Full Text Available The ability to monitor changes in membrane potential is a useful tool for studying neuronal function, but there are only limited options available at present. Here, we have investigated the potential of a commercially available FLIPR membrane potential (FMP dye, developed originally for high throughput screening using a plate reader, for imaging the membrane potential of cultured cells using an epifluorescence-based single cell imaging system. We found that the properties of the FMP dye make it highly suitable for such imaging since 1 its fluorescence displayed a high signal-to-noise ratio, 2 robust signals meant only minimal exposure times of around 5 ms were necessary, and 3 bidirectional changes in fluorescence were detectable resulting from hyper- or depolarising conditions, reaching equilibrium with a time constant of 4-8 s. Measurements were possible independently of whether membrane potential changes were induced by voltage clamping, or manipulating the ionic distribution of either Na(+ or K(+. Since FMP behaves as a charged molecule which accumulates in the cytosol, equations based on the Boltzmann distribution were developed determining that the apparent charge of FMP which represents a measure of the voltage sensitivity of the dye, is between -0.62 and -0.72. Finally, we demonstrated that FMP is suitable for use in a variety of neuronal cell types and detects membrane potential changes arising from spontaneous firing of action potentials and through stimulation with a variety of excitatory and inhibitory neurotransmitters.

  20. The effect of electrode contact resistance and capacitive coupling on Complex Resistivity measurements

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas

    2006-01-01

    The effect of electrode contact resistance and capacitive coupling on complex resistivity (CR) measurements is studied in this paper. An equivalent circuit model for the receiver is developed to describe the effects. The model shows that CR measurements are severely affected even at relatively low...... contact resistances. The model suggests proportionality between the error in the phase measurements and the product of the wire-to-ground capacitance, the contact resistance, the dipole size and the frequency of the measurement. The model behavior is illustrated and confirmed by field data collected...... with the contact resistance artificially increased by resistors. The results emphasize the importance of keeping contact resistance low in CR measurements....

  1. Numerical Electric Field Analysis of Power Status Sensor Observing Power Distribution System Taking into Account Voltage Divider Measurement Circuit

    Science.gov (United States)

    Kubo, Takuro; Furukawa, Tatsuya; Itoh, Hideaki; Fukumoto, Hisao; Wakuya, Hiroshi; Ohchi, Masashi

    We have proposed and preproducted the voltage-current waveform sensor of resin molded type for measuring the power factor and harmonics in power distribution systems. We have executed numerical electromagnetic analyses using the finite element method to estimate the characteristics and behaviours of the sensor. Although the magnetic field analyses for the current sensor have involved the measurement circuit, the electric field analyses have not included the measurement circuit for measuring voltage waveforms of power lines. In this paper, we describe the electric field analyses with the measurement circuit and prove the insulating strength of the proposed sensor permissible to the use in 22kV power distribution systems.

  2. Evaluation study of an ion selective field effect transistor electrode for measuring quality parameters of fuel ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Gonzaga, Fabiano B.; Sobral, Sidney P.; Ribeiro, Carla M.; Goncalves, Mary A., E-mail: fbgonzaga@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia(INMETRO), Duque de Caxias, RJ (Brazil). Div. de Metrologia Quimica

    2013-01-15

    An ion selective field effect transistor (ISFET) electrode was evaluated for measuring pH and acid number (AN) of fuel ethanol and compared to two glass electrodes with different reference filling solutions: KCl aqueous solution (glass-KCl electrode)and LiCl ethanolic solution (glass-LiCl electrode). pH was determined at different measurement times and AN was determined using automatic potentiometric titration. For pH, the glass-KCl electrode showed the best precision and stability, with an average repeatability about four times better when compared to the ISFET electrode for the measurement time of 30 s (as indicated in the ASTM D6423 standard). For AN, the glass-KCl and glass-LiCl electrodes showed similar repeatabilities, which were about three times better than that of the ISFET electrode. In addition, the results from a recovery study demonstrated better accuracy of the glass-LiCl electrode, with a recovery value of 100.1% (author)

  3. Measurements of lithium-ion concentration equilibration processes inside graphite electrodes

    Science.gov (United States)

    Kindermann, Frank M.; Osswald, Patrick J.; Klink, Stefan; Ehlert, Günter; Schuster, Jörg; Noel, Andreas; Erhard, Simon V.; Schuhmann, Wolfgang; Jossen, Andreas

    2017-02-01

    Methods for estimating inner states in a lithium-ion cell require steady state conditions or accurate models of the dynamic processes. Besides often used inner states such as state-of-charge, state-of-health or state-of-function, relaxation processes strongly influence the mentioned states. Inhomogeneous utilization of electrodes and consequent limitations in the operating conditions have recently been brought to attention. Relaxation measurements after an inhomogeneous current distribution through the thickness of an electrode have not been addressed so far. By using a previously developed laboratory cell, we are able to show an inhomogeneous retrieval of lithium-ions from a graphite electrode through the layer with spatial resolution. After this inhomogeneity caused by a constant current operation, equilibration processes are recorded and can be assigned to two different effects. One effect is an equilibration inside the particles (intra-particle) from surface to bulk and vice versa. The other effect is an assimilation between the particles (inter-particle) to reach a homogeneous state-of-charge in each particle throughout the electrode layer. While intra-particle relaxation is observed to be finished within 4 h, inter-particle relaxation through the layer takes more than 40 h. The overall time for both equilibration processes shows to be in the order of 48 h.

  4. Degradation studies of transparent conductive electrodes on electroactive poly(vinylidene fluoride for uric acid measurements

    Directory of Open Access Journals (Sweden)

    Vanessa F Cardoso, Pedro Martins, Gabriela Botelho, Luis Rebouta, Senentxu Lanceros-Méndez and Graca Minas

    2010-01-01

    Full Text Available Biochemical analysis of physiological fluids using, for example, lab-on-a-chip devices requires accurate mixing of two or more fluids. This mixing can be assisted by acoustic microagitation using a piezoelectric material, such as the β-phase of poly(vinylidene fluoride (β-PVDF. If the analysis is performed using optical absorption spectroscopy and β-PVDF is located in the optical path, the material and its conductive electrodes must be transparent. Moreover, if, to improve the transmission of the ultrasonic waves to the fluids, the piezoelectric transducer is placed inside the fluidic structures, its degradation must be assessed. In this paper, we report on the degradation properties of transparent conductive oxides, namely, indium tin oxide (ITO and aluminum-doped zinc oxide, when they are used as electrodes for providing acoustic microagitation. The latter promotes mixing of chemicals involved in the measurement of uric acid concentration in physiological fluids. The results are compared with those for aluminum electrodes. We find that β-PVDF samples with ITO electrodes do not degrade either with or without acoustic microagitation.

  5. Variable Temperature Current-Voltage Measurements of CdTe Solar Cells

    Science.gov (United States)

    Smith, A. D.

    2000-03-01

    We have used a 2" x 2" Peltier heat pump chip powered with 24 V from a computer power supply to build a variable temperature stage for current voltage measurements of solar cells. A voltage divider was used to achieve several different set point temperatures from 25 oC to -24 oC. This system was used with a halogen lamp to study the electrical performance of polycrystalline thin-film solar cells fabricated in our group. These cells have the superstrate structure glass/SnO2:F/CdS/CdTe/metal.(1) The I-V characteristic shows evidence of a blocking back-diode which sets in below room temperature. This behavior will be related to the diffusion into the CdTe of the metals used for our back contact.(2) 1. M. Shao, A. Fischer, D. Grecu, U. Jayamaha, E. Bykov, G. Contreras-Puente, R.G. Bohn, and A.D. Compaan, Appl. Phys. Lett. 69, 3045-3047 (1996). 2. D. Grecu and A.D. Compaan, Appl. Phys. Lett. 75, 361-363 (1999).

  6. Transient Response of Organo-Metal-Halide Solar Cells Analyzed by Time-Resolved Current-Voltage Measurements

    Directory of Open Access Journals (Sweden)

    M. Greyson Christoforo

    2015-11-01

    Full Text Available The determination of the power conversion efficiency of solar cells based on organo-metal-halides is subject to an ongoing debate. As solar cell devices may exhibit very slow transient response, current-voltage scans in different directions may not be congruent, which is an effect often referred to as hysteresis. We here discuss time-resolved current-voltage measurements as a means to evaluate appropriate delay times (voltage settling times to be used in current-voltage measurements of solar cells. Furthermore, this method allows the analysis of transient current response to extract time constants that can be used to compare characteristic differences between devices of varying architecture types, selective contacts and changes in devices due to storage or degradation conditions.

  7. Cold wire constant voltage anemometry to measure temperature fluctuations and its application in a thermoacoustic system

    Science.gov (United States)

    Cleve, Sarah; Jondeau, Emmanuel; Blanc-Benon, Philippe; Comte-Bellot, Geneviève

    2017-04-01

    The knowledge of temperature fluctuations is essential for most thermoacoustic systems. In the present paper, cold wire constant-voltage anemometry (CVA) to measure temperature fluctuations is presented. Corrections for the thermal inertia and for the end losses of the wire are applied during the post-processing. The correction for the thermal inertia of the cold wire is achieved by applying a time dependent thermal lag as proposed originally for a constant-current anemometry (CCA) system. This thermal lag is measured in parallel by a hot wire. The thermal end losses of the wires to their supports are also considered and approximate corrections are proposed. The procedure for the cold wire CVA is validated in the acoustic field of an acoustic resonator with wires of different lengths. A comparison between a CVA and a CCA measurement also confirms the CVA measurement. Furthermore, the proposed measurement procedure is applied close to the stack of a thermoacoustic refrigerator. Supposing a two-dimensional flow, the simultaneous measurement of velocity and temperature fluctuations is possible. This allows a detailed examination of the acoustic field close to the stack, including the study of the correlation between temperature and velocity.

  8. Note: Adhesive stamp electrodes using spider silk masks for electronic transport measurements of supra-micron sized samples

    Science.gov (United States)

    Steven, E.; Jobiliong, E.; Eugenio, P. M.; Brooks, J. S.

    2012-04-01

    A procedure for fabricating adhesive stamp electrodes based on gold coated adhesive tape used to measure electronic transport properties of supra-micron samples in the lateral range 10-100 μm and thickness >1 μm is described. The electrodes can be patterned with a ˜4 μm separation by metal deposition through a mask using Nephila clavipes spider dragline silk fibers. Ohmic contact is made by adhesive lamination of a sample onto the patterned electrodes. The performance of the electrodes with temperature and magnetic field is demonstrated for the quasi-one-dimensional organic conductor (TMTSF)2PF6 and single crystal graphite, respectively.

  9. Mechanical measurements on lithium phosphorous oxynitride coated silicon thin film electrodes for lithium-ion batteries during lithiation and delithiation

    Science.gov (United States)

    Al-Obeidi, Ahmed; Kramer, Dominik; Boles, Steven T.; Mönig, Reiner; Thompson, Carl V.

    2016-08-01

    The development of large stresses during lithiation and delithiation drives mechanical and chemical degradation processes (cracking and electrolyte decomposition) in thin film silicon anodes that complicate the study of normal electrochemical and mechanical processes. To reduce these effects, lithium phosphorous oxynitride (LiPON) coatings were applied to silicon thin film electrodes. Applying a LiPON coating has two purposes. First, the coating acts as a stable artificial solid electrolyte interphase. Second, it limits mechanical degradation by retaining the electrode's planar morphology during cycling. The development of stress in LiPON-coated electrodes was monitored using substrate curvature measurements. LiPON-coated electrodes displayed highly reproducible cycle-to-cycle behavior, unlike uncoated electrodes which had poorer coulombic efficiency and exhibited a continual loss in stress magnitude with continued cycling due to film fracture. The improved mechanical stability of the coated silicon electrodes allowed for a better investigation of rate effects and variations of mechanical properties during electrochemical cycling.

  10. End loss analyzer system for measurements of plasma flux at the C-2U divertor electrode

    Science.gov (United States)

    Griswold, M. E.; Korepanov, S.; Thompson, M. C.

    2016-11-01

    An end loss analyzer system consisting of electrostatic, gridded retarding-potential analyzers and pyroelectric crystal bolometers was developed to characterize the plasma loss along open field lines to the divertors of C-2U. The system measures the current and energy distribution of escaping ions as well as the total power flux to enable calculation of the energy lost per escaping electron/ion pair. Special care was taken in the construction of the analyzer elements so that they can be directly mounted to the divertor electrode. An attenuation plate at the entrance to the gridded retarding-potential analyzer reduces plasma density by a factor of 60 to prevent space charge limitations inside the device, without sacrificing its angular acceptance of ions. In addition, all of the electronics for the measurement are isolated from ground so that they can float to the bias potential of the electrode, 2 kV below ground.

  11. Measurement and Modeling of Personal Exposure to the Electric and Magnetic Fields in the Vicinity of High Voltage Power Lines

    OpenAIRE

    Tourab, Wafa; Babouri, Abdesselam

    2015-01-01

    Background This work presents an experimental and modeling study of the electromagnetic environment in the vicinity of a high voltage substation located in eastern Algeria (Annaba city) specified with a very high population density. The effects of electromagnetic fields emanating from the coupled multi-lines high voltage power systems (MLHV) on the health of the workers and people living in proximity of substations has been analyzed. Methods Experimental Measurements for the Multi-lines power...

  12. Gold Electrodes Modified with Self-Assembled Monolayers for Measuring L-Ascorbic Acid: An Undergraduate Analytical Chemistry Laboratory Experiment

    Science.gov (United States)

    Ito, Takashi; Perera, D. M. Neluni T.; Nagasaka, Shinobu

    2008-01-01

    This article describes an undergraduate electrochemistry laboratory experiment in which the students measure the L-ascorbic acid content of a real sample. Gold electrodes modified with self-assembled monolayers (SAMs) of thioctic acid and cysteamine are prepared to study the effects of surface modification on the electrode reaction of L-ascorbic…

  13. In Situ Spatially and Temporally Resolved Measurements of Salt Concentration between Charging Porous Electrodes for Desalination by Capacitive Deionization

    NARCIS (Netherlands)

    Suss, M.E.; Biesheuvel, P.M.; Baumann, T.E.; Stadermann, M.; Santiago, J.G.

    2014-01-01

    Capacitive deionization (CDI) is an emerging water desalination technique. In CDI, pairs of porous electrode capacitors are electrically charged to remove salt from brackish water present between the electrodes. We here present a novel experimental technique allowing measurement of spatially and tem

  14. The construction of a magnetite electrode for measurement of the electrochemical property

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myongjin; Kim, Hong Pyo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Flow accelerated corrosion (FAC) causes severe damage to secondary piping systems. An accident from FAC occurred at the Oyster Creek nuclear power plant (NPP) in 1978. Other NPPs such as Surry 2 and Mihama 3 have also experienced an FAC that induced damage to the carbon steel piping. FAC is influenced by many factors such as the water chemistry (temperature, pH, dissolved oxygen (D. O.) in a solution, and etc.), chemical composition of carbon steel, and fluid dynamics. Magnetite is formed at the inner surface of carbon steel, and protects the integrity of pipes from damage. The magnetite has a stable state at each equilibrium condition, so that it can be dissolved into the fluid under conditions that satisfy the equilibrium state. The iron solubility can be calculated by considering the reaction equilibrium constants for prediction of the change in the magnetite layer. On the other hand, it is necessary to measure the experimental solubility to compare the theoretical data and the experimental data. In addition, the solubility of magnetite can be predicted by measuring the electrochemical experiments. However, there are few studies related to the electrochemical property of magnetite owing to the difficulty of the electrode fabrication. In the present work, a magnetite electrode was prepared using a dipping method, and the electrochemical property of the magnetite electrode was measured in an alkaline solution.

  15. Normalization of voltage-sensitive dye signal with functional activity measures.

    Directory of Open Access Journals (Sweden)

    Kentaroh Takagaki

    Full Text Available In general, signal amplitude in optical imaging is normalized using the well-established DeltaF/F method, where functional activity is divided by the total fluorescent light flux. This measure is used both directly, as a measure of population activity, and indirectly, to quantify spatial and spatiotemporal activity patterns. Despite its ubiquitous use, the stability and accuracy of this measure has not been validated for voltage-sensitive dye imaging of mammalian neocortex in vivo. In this report, we find that this normalization can introduce dynamic biases. In particular, the DeltaF/F is influenced by dye staining quality, and the ratio is also unstable over the course of experiments. As methods to record and analyze optical imaging signals become more precise, such biases can have an increasingly pernicious impact on the accuracy of findings, especially in the comparison of cytoarchitechtonic areas, in area-of-activation measurements, and in plasticity or developmental experiments. These dynamic biases of the DeltaF/F method may, to an extent, be mitigated by a novel method of normalization, DeltaF/DeltaF(epileptiform. This normalization uses as a reference the measured activity of epileptiform spikes elicited by global disinhibition with bicuculline methiodide. Since this normalization is based on a functional measure, i.e. the signal amplitude of "hypersynchronized" bursts of activity in the cortical network, it is less influenced by staining of non-functional elements. We demonstrate that such a functional measure can better represent the amplitude of population mass action, and discuss alternative functional normalizations based on the amplitude of synchronized spontaneous sleep-like activity. These findings demonstrate that the traditional DeltaF/F normalization of voltage-sensitive dye signals can introduce pernicious inaccuracies in the quantification of neural population activity. They further suggest that normalization

  16. Derivation of armature displacement and movement disturbances from current and voltage measurements on solenoid operated valves

    Energy Technology Data Exchange (ETDEWEB)

    Louati, Iskander Alexandre [AREVA NP GmbH (Germany). Service Sector Germany

    2009-07-01

    As part of the electric drive mechanisms of the safety system in nuclear power plants safety related solenoid operated valves (SOVs) are subject to design control, commissioning tests and periodical in-service inspections. AREVA has developed and qualified many methods and tools that have been embedded into as software tools called DAM for diagnosis and evaluation of the valve performance according to the KTA requirements. In the special case of COVs tracing the electric measurements with ADAM helps to detect anomalies at the SOVs and esp. those related to disturbances of the armature moved. The disturbances to be tested are divided into electrical and mechanical disturbances: voltage insufficiency, switch chattering; degradation of spring load, friction collaterally to armature displacement, partial or total obstruction of the armature.

  17. Measurement ot the switching over-voltages at the disconnection of the high voltage shunt reactors in the Romanian power system

    Energy Technology Data Exchange (ETDEWEB)

    Stroica, Paul Constantin; Merfu, Ion; Stroica, Mihail; Merfu, Marius; Cojocaru, Florian; Stefan, Dinu; Cojocaru, Mihai

    2010-09-15

    The paper presents the measurements of the switching over-voltages made in the Romanian Power System, at the 400/220/110 kV Urechesti substation at the disconnection of a 400 kV, 100 MVAr shunt reactor type DFAL, Siemens, Germany, in 3 consecutive versions. The first one is for shunt reactor controlled by live-tank oil circuit breaker, the second one is for shunt reactor controlled by SF6 circuit breaker, and the third one is for shunt reactor controlled by SF6 circuit breaker and synchronize device.

  18. Online Partial Discharge Measurement of a High-voltage Direct Current Converter Wall-bushing%Online Partial Discharge Measurement of a High-voltage Direct Current Converter Wall-bushing

    Institute of Scientific and Technical Information of China (English)

    Nathan D. Jacob; William M. McDermid; Behzad Kordi

    2011-01-01

    An online partial discharge (PD) measurement performed on a high voltage direct current (HVDC) wall bushing successfully identified the presence of internal discharges. The wall bushing is a sulfur hexafluoride gas-insu- lated bushing, rated for 500 kV dc and terminated on a thyristor-controlled HVDC converter bridge. The measure- ment of PD within the HVDC station environment is particularly challenging due to the high levels of electromagnetic noise caused by thyristor switching events and external air-corona from the neighboring high-voltage equipment. An additional challenge is the "mixed" voltage stress on the bushing insulation, which has both ac and dc high-voltage components. There are also fast transients during the firing of thyristors in the HVDC conversion process that cause added stress to the insulation. As a result, the analysis and interpretation of PD data for HVDC equipment is more complex; PD pulses may occur in response to the ac, dc, or switching transient voltage stresses. In this paper, an on- line PD measurement strategy for noise filtering and isolation of PD sources within the bushing are discussed. The PD measurement data is plotted on a phase-resolved diagram where the line supply power cord voltage was used as a reference. The phase-resolved diagram appears to suggest that the fast transients, caused during switching, trigger some PD events. Measurements were also performed with the aid of a modern PD measurement instrument having noise separation capabilities. The findings from the online PD measurements are verified with physical evidence, found after the bushing was removed from service, suggested internal PD had occurred inside the bushing.

  19. Polysulfide transport through separators measured by a linear voltage sweep method

    Science.gov (United States)

    Cui, Yi; Fu, Yongzhu

    2015-07-01

    Shuttle of polysulfide from the sulfur cathode to lithium metal anode in rechargeable lithium-sulfur batteries is a critical issue hindering cycling efficiency and life. Several approaches have been developed to minimize it including polysulfide-blocking separators; there is a need for measuring polysulfide transport through separators. We here show a linear voltage sweep method to measure anodic (oxidization) current of polysulfide crossed separators, which can be used as a quantitative measurement of the polysulfide transport. The electrochemical oxidation of polysulfide is diffusion controlled. The electrical charge in Coulombs produced by the oxidation of polysulfide is linearly related to the concentration of polysulfide within a certain range (≤0.5 M). Separators with a high porosity (large pore size) show high anodic currents, resulting in fast capacity degradation and low Coulombic efficiencies in Li-S cells. These results demonstrate this method can be used to correlate the polysulfide transport through separators with the separator structure and battery performance, therefore provide guidance for developing new separators for lithium-sulfur batteries.

  20. Fabrication of interdigitated electrodes (IDEs) using basic conventional lithography for pH measurement

    Science.gov (United States)

    Farehanim, M. A.; Hashim, U.; Azizah, N.; Fatin, M. F.; Azman, A. H.

    2017-03-01

    Interdigitated electrode (IDEs) can be created by straightforward procedure utilizing essential routine lithography process. Besides, IDEs based biosensors have an incredible potential to serve as ultra-high sensitive and mark free bio detecting application. These biosensors are reasonable in recognizing DNA biomolecules, pH solution, proteins and even single virus infections. In this test, we report the geometrical components and execution of IDEs for pH solution. The electrodes were intended for 10micron sizes utilizing top-down approach was used in the development of resist mask and electrode from silicon oxide (SiO2) wafer including checking on scanning electron magnifying instrument (SEM) based UV exposure using mask aligner. The pH level detection was performed in based on several types of aqueous pH buffer solutions (pH 4, pH 7and pH 10) to test the electrical reaction of the sensor. The Morphology and electrical reactions have been directed to demonstrate the qualities of the IDEs sensor on pH measurement.

  1. Static Electrode DC Resistivity Measurement at Surface Water for Pond Subsurface Layer Imaging

    Science.gov (United States)

    Sumintadireja, P.; Irawan, D.

    2016-01-01

    Resistivity methods in marine applications show slightly different processing techniques from land based resistivity surveys. Special DC resistivity instruments need to overcome difficulties in arranging the electrode with straight array lines and position. Some geoelectrical instrument manufacturers developed equipment which is able to measure resistivity values and positions in real time. In this paper we demonstrate an application of ordinary geoelectrical instruments for resistivity acquisition in water environment. This study is motivated by the inability to apply conventional DC resistivity instruments in water environment. Land resistivity survey array is arranged on the surface of water using static electrode mode. The method has been tested in various environments, such as ponds/lakes with quiet until rough waves and also measurements at coastal environments. Measurement at the ponds/lakes water environment resulted in data that are almost identic to the measurements obtained using standard land DC resistivity method. On the other hand the measurement in coastal environment does not work properly, possibly due to the lack of power source.

  2. Construction and in vitro test of a new electrode for dentin resistance measurement.

    Science.gov (United States)

    Stein, Steffen; Gente, Michael

    2013-10-01

    It is necessary to reduce the tooth substance before treating a tooth with a dental crown. The preparation often requires reduction of the dentin. This results in a dentin wound and a thinner substance over the pulp, increases the risk of inflammation, and could result in necrosis of the pulp. To give the dentist information about the amount of dentin over the pulp during preparation, the Prepometer was developed. The function of this device is based on the measurement of the electric resistance of the tooth substance. The measuring behavior of the first-generation Prepometer is characterized by smaller values of electric resistance before reaching full contact of the measuring head to the dentin surface and the actual value RT. This measuring behavior can mislead inexperienced therapists with inaccurate values that suggest thinner dentin than the reality. In this study, a new electrode based on the technology of active guard drive was constructed to overcome this issue. The results show that improvement in the measuring behavior of the new electrode could be achieved, eliminating the earlier disadvantage of the Prepometer.

  3. The first results of electrode biasing experiments in the IR-T1 tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Ghoranneviss, M; Salar Elahi, A; Mohammadi, S; Arvin, R, E-mail: salari_phy@yahoo.co [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, PO Box 14665-678, Tehran (Iran, Islamic Republic of)

    2010-09-15

    We report here the first results of our movable electrode biasing experiments performed in the IR-T1 tokamak. For this study, a movable electrode biasing system was designed, constructed and installed on the IR-T1 tokamak. A positive voltage was applied to an electrode inserted in the tokamak limiter. The plasma current, poloidal and radial components of the magnetic fields, loop voltage and diamagnetic flux in the absence and presence of the biased electrode were measured. Results of the improvement done to plasma equilibrium behaviour are compared and discussed in this paper.

  4. Dual Band Electrodes in Generator-Collector Mode: Simultaneous Measurement of Two Species

    CERN Document Server

    Barnes, Edward O; Dale, Sara E C; Marken, Frank; Compton, Richard G

    2013-01-01

    A computational model for the simulation of a double band collector-generator experiment is applied to the situation where two electrochemical reactions occur concurrently. It is shown that chronoamperometric measurements can be used to take advantage of differences in diffusion coefficients to measure the concentrations of both electroactive species simultaneously, by measuring the time at which the collection efficiency reaches a specific value. The separation of the electrodes is shown to not affect the sensitivity of the method (in terms of percentage changes in the measured time to reach the specified collection efficiency), but wider gaps can provide a greater range of (larger) absolute values of this characteristic time. It is also shown that measuring the time taken to reach smaller collection efficiencies can allow for the detection of smaller amounts of whichever species diffuses faster. The case of a system containing both ascorbic acid and opamine in water is used to exemplify the method, and it i...

  5. Evaluation of the electrode performance for PAFC by using acid absorption, acceleration and ac-impedance measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang-Soo; Song, Rak-Hyun; Choi, Byung-Woo [Korea Institute of Energy Research, Taejon (Korea, Republic of)] [and others

    1996-12-31

    In PAFC, the degradation on cathode electrode caused by carbon corrosion, platinum dissolution and growth is especially severe. An acceleration test is a good technique for evaluating the degradation of electrode performance, because it does not need long time. Coleman et al used thermal cycling and on-off cycling as an acceleration test. Song et al showed that hydrogen shortage decreased the electrode performance more rapidly than that of air shortage in gas shortage test. Honji et al reported that the rate of coarsening of Pt particle is rapid in open circuit potential and this is one of major causes on the performance degradation of electrode. The cathode performance has been studied by using acid absorption, acceleration and ac-impedance measurements as functions of the polytetrafluoroethylene (PTFE) contents and sintering temperatures of the electrode.

  6. Electrodeposited Porous Mn1.5Co1.5O4/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors

    Directory of Open Access Journals (Sweden)

    Guan-Ting Pan

    2017-03-01

    Full Text Available Mesoporous Mn1.5Co1.5O4 (MCO spinel films were prepared directly on a conductive nickel (Ni foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni-15 min electrode (electrodeposition time: 15 min exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively. Further, an asymmetric supercapacitor that utilizes (MCO/Ni-15 min as a positive electrode, a plasma-treated activated carbon (PAC/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO3 gel electrolyte (denoted as (PAC/Ni//(MCO/Ni-15 min was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg−1 and a power density of 1.01 kW·kg−1 at 1 A·g−1. After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni//(MCO/Ni-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling.

  7. Focused ion beam processing to fabricate ohmic contact electrodes on a bismuth nanowire for Hall measurements.

    Science.gov (United States)

    Murata, Masayuki; Hasegawa, Yasuhiro

    2013-09-26

    Ohmic contact electrodes for four-wire resistance and Hall measurements were fabricated on an individual single-crystal bismuth nanowire encapsulated in a cylindrical quartz template. Focused ion beam processing was utilized to expose the side surfaces of the bismuth nanowire in the template, and carbon and tungsten electrodes were deposited on the bismuth nanowire in situ to achieve electrical contacts. The temperature dependence of the four-wire resistance was successfully measured for the bismuth nanowire, and a difference between the resistivities of the two-wire and four-wire methods was observed. It was concluded that the two-wire method was unsuitable for estimation of the resistivity due to the influence of contact resistance, even if the magnitude of the bismuth nanowire resistance was greater than the kilo-ohm order. Furthermore, Hall measurement of a 4-μm-diameter bismuth microwire was also performed as a trial, and the evaluated temperature dependence of the carrier mobility was in agreement with that for bulk bismuth, which indicates that the carrier mobility was successfully measured using this technique. PACS: 81.07.Gf.

  8. Radio frequency cavity analysis, measurement, and calibration of absolute Dee voltage for K-500 superconducting cyclotron at VECC, Kolkata

    Science.gov (United States)

    Som, Sumit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Duttagupta, Anjan

    2013-02-01

    Variable Energy Cyclotron Centre has commissioned a K-500 superconducting cyclotron for various types of nuclear physics experiments. The 3-phase radio-frequency system of superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.20, respectively. The analysis of the RF cavity has been carried out using 3D Computer Simulation Technology (CST) Microwave Studio code and various RF parameters and accelerating voltages ("Dee" voltage) are calculated from simulation. During the RF system commissioning, measurement of different RF parameters has been done and absolute Dee voltage has been calibrated using a CdTe X-ray detector along with its accessories and known X-ray source. The present paper discusses about the measured data and the simulation result.

  9. Investigation Of The EMF Versus State Of Charge Behavior Of Individual Electrodes In New And Cycled Sony 18650 HC Cells

    Science.gov (United States)

    Dudley, G.; Mattle, T.

    2011-10-01

    Individual electrode EMFs of new and cycled Sony 18650 HC cells have been measured with the help of a lithium reference electrode inserted into complete cells. Results have revealed the relative contribution of each electrode to voltage hysteresis (the difference in cell EMF between charge and discharge at the same state of charge).They have also shown changes to the shape of the positive electrode EMF versus state of charge in cycled compared to beginning of life cells.

  10. Measurement system of high voltage and high current measurements at INMETRO - Brazilian Institute for Metrology, Standardization and Industrial Quality; Sistema de medicao de alta tensao e alta corrente do INMETRO - Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Vitorio, Patricia Cals de O.; Franca, Ademir Martins de; Soares, Marco Aurelio; Pereira, Luiz Napoleao; Costa, Danielli Guimaraes; Moreira, Giselle Cobica; Nascimento, Paulo Roberto Mesquita [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (DIMCI/INMETRO), Duque de Caxias, RJ (Brazil). Diretoria de Metrologia Cientifica e Industrial], E-mail: latra@inmetro.gov.br

    2009-07-01

    This work presents the basic characteristics and uncertainties of the calibration equipment in high voltage and high current available at the INMETRO: system of measurement in alternating high voltage up to 200 kV, system of measurement in alternating current up to 2 k A, and system of measurement in continuous high voltage up to 150 kV.

  11. Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7: e0139766

    National Research Council Canada - National Science Library

    Sh Nadzirah; N Azizah; Uda Hashim; Subash C B Gopinath; Mohd Kashif

    2015-01-01

    .... In the present study, we have generated and examined the potential of titanium dioxide (TiO2) crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA...

  12. Electrode thickness measurement of a Si(Li) detector for the SIXA array

    OpenAIRE

    Tikkanen, T. (Tiia); Hamalainen, K.; Huotari, S.

    1997-01-01

    Cathode electrodes of the Si(Li) detector elements of the SIXA X-ray spectrometer array are formed by gold-palladium alloy contact layers. The equivalent thickness of gold in one element was measured by observing the characteristic L-shell X-rays of gold excited by monochromatised synchrotron radiation with photon energies above the L3 absorption edge of gold. The results obtained at 4 different photon energies below the L2 edge yield an average value of 22.4(35) nm which is consistent with t...

  13. Two-Point Stretchable Electrode Array for Endoluminal Electrochemical Impedance Spectroscopy Measurements of Lipid-Laden Atherosclerotic Plaques.

    Science.gov (United States)

    Packard, René R Sevag; Zhang, XiaoXiao; Luo, Yuan; Ma, Teng; Jen, Nelson; Ma, Jianguo; Demer, Linda L; Zhou, Qifa; Sayre, James W; Li, Rongsong; Tai, Yu-Chong; Hsiai, Tzung K

    2016-09-01

    Four-point electrode systems are commonly used for electric impedance measurements of biomaterials and tissues. We introduce a 2-point system to reduce electrode polarization for heterogeneous measurements of vascular wall. Presence of endoluminal oxidized low density lipoprotein (oxLDL) and lipids alters the electrochemical impedance that can be measured by electrochemical impedance spectroscopy (EIS). We developed a catheter-based 2-point micro-electrode configuration for intravascular deployment in New Zealand White rabbits. An array of 2 flexible round electrodes, 240 µm in diameter and separated by 400 µm was microfabricated and mounted on an inflatable balloon catheter for EIS measurement of the oxLDL-rich lesions developed as a result of high-fat diet-induced hyperlipidemia. Upon balloon inflation, the 2-point electrode array conformed to the arterial wall to allow deep intraplaque penetration via alternating current (AC). The frequency sweep from 10 to 300 kHz generated an increase in capacitance, providing distinct changes in both impedance (Ω) and phase (ϕ) in relation to varying degrees of intraplaque lipid burden in the aorta. Aortic endoluminal EIS measurements were compared with epicardial fat tissue and validated by intravascular ultrasound and immunohistochemistry for plaque lipids and foam cells. Thus, we demonstrate a new approach to quantify endoluminal EIS via a 2-point stretchable electrode strategy.

  14. Non-invasive measurement of hepatic oxygenation by an oxygen electrode in human orthotopic liver transplantation.

    Science.gov (United States)

    Seifalian, A M; Mallett, S; Piasecki, C; Rolles, K; Davidson, B R

    2000-06-01

    Precise evaluation of graft reperfusion is difficult in clinical liver transplantation. The oxygen electrode (OE) is a novel technique to detect blood flow indirectly by measuring the quantity of oxygen which can diffuse from the hepatic tissue to the surface electrode. Application of the surface OE does not influence the liver blood flow or parenchymal perfusion. Adequate graft oxygenation is essential to the outcome of organ transplantation and has not previously been analysed intra-operatively in liver transplant recipients. The OE was applied to the surface of the graft intra-operatively in 22 human liver grafts after restoring portal vein and hepatic artery inflow. OE readings were compared with liver blood flow using an electromagnetic flowmeter (EMF). Intra-operative haemodynamics and donor organ parameters known to influence graft function were correlated with the OE readings. There was a significant correlation (r=0.89; poxygenation using the OE and total liver blood flow measured by EMF. The tissue oxygenation measurements were reproducible with a coefficient of variation of 5%. The hepatic tissue oxygenation increased significantly from baseline following venous reperfusion of the graft (282+/-23 vs 3107+/-288 (+/-SE) nA, poxygen perfusion. There was significant negative correlation (r=0.80, poxygenation. The OE provides a reliable, cheap and non-invasive method of monitoring liver graft oxygenation and perfusion during transplantation.

  15. Use of vacuum tubes in test instrumentation for measuring characteristics of fast high-voltage semiconductor devices

    Science.gov (United States)

    Berning, D.

    1981-01-01

    Circuits are described that permit measurement of fast events occurring in power semiconductors. These circuits were developed for the dynamic characterization of transistors used in inductive-load switching applications. Fast voltage clamping using vacuum diodes is discussed, and reference is made to a unique circuit that was built for performing nondestructive, reverse-bias, second-breakdown tests on transistors.

  16. Technological Aspects: High Voltage

    CERN Document Server

    Faircloth, D C

    2013-01-01

    This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

  17. Charge-pump voltage converter

    Science.gov (United States)

    Brainard, John P.; Christenson, Todd R.

    2009-11-03

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  18. Organs-on-Chips with combined multi-electrode array and transepithelial electrical resistance measurement capabilities.

    Science.gov (United States)

    Maoz, Ben M; Herland, Anna; Henry, Olivier Y F; Leineweber, William D; Yadid, Moran; Doyle, John; Mannix, Robert; Kujala, Ville J; FitzGerald, Edward A; Parker, Kevin Kit; Ingber, Donald E

    2017-06-27

    Here we demonstrate that microfluidic cell culture devices, known as Organs-on-a-Chips can be fabricated with multifunctional, real-time, sensing capabilities by integrating both multi-electrode arrays (MEAs) and electrodes for transepithelial electrical resistance (TEER) measurements into the chips during their fabrication. To prove proof-of-concept, simultaneous measurements of cellular electrical activity and tissue barrier function were carried out in a dual channel, endothelialized, heart-on-a-chip device containing human cardiomyocytes and a channel-separating porous membrane covered with a primary human endothelial cell monolayer. These studies confirmed that the TEER-MEA chip can be used to simultaneously detect dynamic alterations of vascular permeability and cardiac function in the same chip when challenged with the inflammatory stimulus tumor necrosis factor alpha (TNF-α) or the cardiac targeting drug isoproterenol. Thus, this Organ Chip with integrated sensing capability may prove useful for real-time assessment of biological functions, as well as response to therapeutics.

  19. Dependence of Impedance Measurement Sensitivity of Cell Growth on Sensing Area of Circular Interdigitated Electrode.

    Science.gov (United States)

    Park, Jinsoo; Hwang, Kyo Seon; Cho, Sungbo

    2015-10-01

    A circular interdigitated electrode (IDE) array for label-free and real-time impedance monitoring of cell growth was fabricated and evaluated. Both the width and spacing of fingers were 50 μm, and the exposed sensing area of the circular IDE was 1.3~3.4 mm. The electrical characteristics of the fabricated circular IDE were modeled as an equivalent circuit, and the values of the circuit parameters extrapolated from the fitting to the measured spectra in different concentrations of NaCl or sensing areas of the circular IDE were analyzed. During cell growth, the resistance of cells extrapolated from the fitting was increased and the maximum rate of change in the real part of the impedance was observed at frequencies of 10 to 22 kHz. The normalized real part of the impedance measured at 10 kHz during cell growth was increased more with decreasing the electrode sensing area, albeit the number of cells to be investigated showed a corresponding increase.

  20. Time varying voltage combustion control and diagnostics sensor

    Science.gov (United States)

    Chorpening, Benjamin T.; Thornton, Jimmy D.; Huckaby, E. David; Fincham, William

    2011-04-19

    A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

  1. In situ spatially and temporally resolved measurements of salt concentration between charging porous electrodes for desalination by capacitive deionization.

    Science.gov (United States)

    Suss, Matthew E; Biesheuvel, P M; Baumann, Theodore F; Stadermann, Michael; Santiago, Juan G

    2014-01-01

    Capacitive deionization (CDI) is an emerging water desalination technique. In CDI, pairs of porous electrode capacitors are electrically charged to remove salt from brackish water present between the electrodes. We here present a novel experimental technique allowing measurement of spatially and temporally resolved salt concentration between the CDI electrodes. Our technique measures the local fluorescence intensity of a neutrally charged fluorescent probe which is collisionally quenched by chloride ions. To our knowledge, our system is the first to measure in situ and spatially resolved chloride concentration in a laboratory CDI cell. We here demonstrate good agreement between our dynamic measurements of salt concentration in a charging, millimeter-scale CDI system to the results of a modified Donnan porous electrode transport model. Further, we utilize our dynamic measurements to demonstrate that salt removal between our charging CDI electrodes occurs on a longer time scale than the capacitive charging time scales of our CDI cell. Compared to typical measurements of CDI system performance (namely, measurements of outflow ionic conductivity), our technique can enable more advanced and better-controlled studies of ion transport in CDI systems, which can potentially catalyze future performance improvements.

  2. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Benjamin J. [Department of Physics and Astronomy, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089-0484 (United States); El-Naggar, Mohamed Y., E-mail: mnaggar@usc.edu [Department of Physics and Astronomy, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089-0484 (United States); Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-0484 (United States); Department of Chemistry, University of Southern California, Los Angeles, California 90089-0484 (United States)

    2015-06-15

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

  3. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces.

    Science.gov (United States)

    Gross, Benjamin J; El-Naggar, Mohamed Y

    2015-06-01

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

  4. A combined electrochemical and optical trapping platform for measuring single cell respiration rates at electrode interfaces

    Science.gov (United States)

    Gross, Benjamin J.; El-Naggar, Mohamed Y.

    2015-06-01

    Metal-reducing bacteria gain energy by extracellular electron transfer to external solids, such as naturally abundant minerals, which substitute for oxygen or the other common soluble electron acceptors of respiration. This process is one of the earliest forms of respiration on earth and has significant environmental and technological implications. By performing electron transfer to electrodes instead of minerals, these microbes can be used as biocatalysts for conversion of diverse chemical fuels to electricity. Understanding such a complex biotic-abiotic interaction necessitates the development of tools capable of probing extracellular electron transfer down to the level of single cells. Here, we describe an experimental platform for single cell respiration measurements. The design integrates an infrared optical trap, perfusion chamber, and lithographically fabricated electrochemical chips containing potentiostatically controlled transparent indium tin oxide microelectrodes. Individual bacteria are manipulated using the optical trap and placed on the microelectrodes, which are biased at a suitable oxidizing potential in the absence of any chemical electron acceptor. The potentiostat is used to detect the respiration current correlated with cell-electrode contact. We demonstrate the system with single cell measurements of the dissimilatory-metal reducing bacterium Shewanella oneidensis MR-1, which resulted in respiration currents ranging from 15 fA to 100 fA per cell under our measurement conditions. Mutants lacking the outer-membrane cytochromes necessary for extracellular respiration did not result in any measurable current output upon contact. In addition to the application for extracellular electron transfer studies, the ability to electronically measure cell-specific respiration rates may provide answers for a variety of fundamental microbial physiology questions.

  5. Carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool

    Science.gov (United States)

    Cai, Yu; Sha, Shuang

    2016-09-01

    This paper proposes a new carrier-interleaved orthogonal multi-electrode multi-carrier resistivity-measurement tool used in a cylindrical borehole environment during oil-based mud drilling processes. The new tool is an orthogonal frequency division multiplexing access-based contactless multi-measurand detection tool. The tool can measure formation resistivity in different azimuthal angles and elevational depths. It can measure many more measurands simultaneously in a specified bandwidth than the legacy frequency division multiplexing multi-measurand tool without a channel-select filter while avoiding inter-carrier interference. The paper also shows that formation resistivity is not sensitive to frequency in certain frequency bands. The average resistivity collected from N subcarriers can increase the measurement of the signal-to-noise ratio (SNR) by N times given no amplitude clipping in the current-injection electrode. If the clipping limit is taken into account, with the phase rotation of each single carrier, the amplitude peak-to-average ratio can be reduced by 3 times, and the SNR can achieve a 9/N times gain over the single-carrier system. The carrier-interleaving technique is also introduced to counter the carrier frequency offset (CFO) effect, where the CFO will cause inter-pad interference. A qualitative analysis and simulations demonstrate that block-interleaving performs better than tone-interleaving when coping with a large CFO. The theoretical analysis also suggests that increasing the subcarrier number can increase the measurement speed or enhance elevational resolution without sacrificing receiver performance. The complex orthogonal multi-pad multi-carrier resistivity logging tool, in which all subcarriers are complex signals, can provide a larger available subcarrier pool than other types of transceivers.

  6. A High Revolution Speed Noncontact Ultrasonic Motor Driven by a Non-Symmetrical Electrode

    Institute of Scientific and Technical Information of China (English)

    YANG Bin; LIU Jing-Quan; CHEN Di; CAI Bing-Chu

    2005-01-01

    @@ A noncontact ultrasonic motor based on a non-symmetrical electrode is proposed. This motor has the advantages of using a simple driving electrode and having a high revolution speed. The revolution speed of its three-blade rotor can reach 5100rpm under a driving voltage of 20 V. A method operated easily is proposed to measure the output torque.

  7. Impulse space charge and dielectric characteristics of an Al2O3 nanoparticle suspension in propylene carbonate using various electrode materials

    Directory of Open Access Journals (Sweden)

    Qing Yang

    2016-09-01

    Full Text Available We tested the impulse breakdown voltage of Al2O3 “nano-modified” propylene carbonate between different electrode materials. At any given concentration, the breakdown voltage was highest with stainless steel electrodes, followed by copper, and then aluminum. The space charge and electric field distributions were measured too. Results show that less space charge was injected by the electrodes, and the electric field was less distorted, than in pure propylene carbonate. However, the hoped-for reduction of the influence of the electrodes did not take place. Substantial differences in the space charge density and electric field distortion remained between the different electrode materials.

  8. Determination of polarization fields in group III-nitride heterostructures by capacitance-voltage-measurements

    Science.gov (United States)

    Rychetsky, Monir; Koslow, Ingrid; Avinc, Baran; Rass, Jens; Wernicke, Tim; Bellmann, Konrad; Sulmoni, Luca; Hoffmann, Veit; Weyers, Markus; Wild, Johannes; Zweck, Josef; Witzigmann, Bernd; Kneissl, Michael

    2016-03-01

    The polarization fields in wurtzite group III-nitrides strongly influence the optical properties of InAlGaN-based light emitters, e.g., the electron and hole wave function overlap in quantum wells. In this paper, we propose a new approach to determine these fields by capacitance-voltage measurements (CVM). Sheet charges generated by a change of the microscopic polarization at heterointerfaces influence the charge distribution in PIN junctions and therefore the depletion width and the capacitance. We show that it is possible to determine the strength and direction of the internal fields by comparing the depletion widths of two PIN junctions, one influenced by internal polarization fields and one without as a reference. For comparison, we conducted coupled Poisson/carrier transport simulations on the CVM of the polarization-influenced sample. We also demonstrate the feasibility and limits of the method by determining the fields in GaN/InGaN and GaN/AlGaN double heterostructures on (0001) c-plane grown by metal organic vapor phase epitaxy and compare both evaluation methods. The method yields (-0.50 ± 0.07) MV/cm for In0.08Ga0.92N/GaN, (0.90 ± 0.13) MV/cm for Al0.18Ga0.82N/GaN, and (2.0 ± 0.3) MV/cm for Al0.31Ga0.69N/GaN heterostructures.

  9. Determination of polarization fields in group III-nitride heterostructures by capacitance-voltage-measurements

    Energy Technology Data Exchange (ETDEWEB)

    Rychetsky, Monir, E-mail: monir.rychetsky@physik.tu-berlin.de; Avinc, Baran; Wernicke, Tim; Bellmann, Konrad; Sulmoni, Luca [Institute of Solid State Physics, Technische Universität Berlin, Berlin (Germany); Koslow, Ingrid; Rass, Jens; Kneissl, Michael [Institute of Solid State Physics, Technische Universität Berlin, Berlin (Germany); Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin (Germany); Hoffmann, Veit; Weyers, Markus [Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin (Germany); Wild, Johannes; Zweck, Josef [Fakultät für Physik, University of Regensburg, Regensburg (Germany); Witzigmann, Bernd [Computational Electronics and Photonics Group and CINSaT, University of Kassel, Kassel (Germany)

    2016-03-07

    The polarization fields in wurtzite group III-nitrides strongly influence the optical properties of InAlGaN-based light emitters, e.g., the electron and hole wave function overlap in quantum wells. In this paper, we propose a new approach to determine these fields by capacitance-voltage measurements (CVM). Sheet charges generated by a change of the microscopic polarization at heterointerfaces influence the charge distribution in PIN junctions and therefore the depletion width and the capacitance. We show that it is possible to determine the strength and direction of the internal fields by comparing the depletion widths of two PIN junctions, one influenced by internal polarization fields and one without as a reference. For comparison, we conducted coupled Poisson/carrier transport simulations on the CVM of the polarization-influenced sample. We also demonstrate the feasibility and limits of the method by determining the fields in GaN/InGaN and GaN/AlGaN double heterostructures on (0001) c-plane grown by metal organic vapor phase epitaxy and compare both evaluation methods. The method yields (−0.50 ± 0.07) MV/cm for In{sub 0.08}Ga{sub 0.92}N/GaN, (0.90 ± 0.13) MV/cm for Al{sub 0.18}Ga{sub 0.82}N/GaN, and (2.0 ± 0.3) MV/cm for Al{sub 0.31}Ga{sub 0.69}N/GaN heterostructures.

  10. Plasma facilities measuring equipment and high-voltage systems for basic research and technology

    Energy Technology Data Exchange (ETDEWEB)

    Sadowski, M.; Pawlowicz, W. [eds.] [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

    1994-12-31

    The report presents short description and the main technical data of various devices and systems designed and constructed at the Thermonuclear Research Dept. of the Soltan Institute for Nuclear Studies (SINS) in Swierk n. Warsaw, Poland. Different Plasma-Focus (PF) facilities of energy ranging from several kJ to 360 kJ, as well as the Ion Implosion Facilities of energy equal to 400 kJ, are shortly described. We present different cameras and analyzers used for studies of ions and X-rays. We also describe e.g. IONOTRONs used for material engineering. High-Voltage Pulse Generators developed for the voltage range from 40 kV to 2.4 MV, various Data Acquisition Systems, and special Vacuum Stands. Some selected technical units used in high-voltage systems are also presented. (author). 32 figs.

  11. 3D PIV measurements of the EHD flow patterns in a narrow lectrostatic precipitator with wire-plate or wire-flocking electrodes

    Science.gov (United States)

    Podliński, J.; Kocik, M.; Barbucha, R.; Niewulis, A.; Mizeraczyk, J.; Mizuno, A.

    2006-10-01

    The results of 3-dimensional (3D) Particle Image Velocimetry (PIV) measurements of the electrohydrodynamic (EHD) flow patterns in a narrow electrostatic precipitator (ESP) are presented in this paper. The ESP was an acrylic parallelepiped with a wire discharge electrode and two plane collecting electrodes. In contrary to typical ESPs the wire electrode was placed along the gas flow, in the ESP centre, in the halfway between collecting electrodes. Either two smooth stainless steel plates or two stainless steel meshes with nylon flocks were used as the collecting electrodes. They were placed on the top and bottom of the ESP. The PIV measurements were carried out in two parallel planes, placed perpendicularly to the collecting electrodes and parallel to the wire electrode. The obtained results showed some similarities and differences of a 3D particle flow in the ESP with plate or flocking electrodes.

  12. An improved device for bioimpedance deviation measurements based on 4-electrode half bridge

    Science.gov (United States)

    Liu, Yang; Qiao, Xiaoyan; Li, Gang; Lin, Ling

    2016-10-01

    Researches on monitoring the body fluid changes have attracted much attention during recent years. Real-time bioimpedance deviation detection has good potential for evaluating body fluid changes. In this paper, an improved device based on the self-balancing half bridge and the 4-electrode technique is proposed, which is able to detect minor bioimpedance deviations. The 4-electrode technique is used to remove the interference from contact impedance. Furthermore, the automatic balancing half bridge is utilized to deduct the high-level static impedance baseline, and thus, the dynamic range is enlarged. Moreover, a digital lock-in algorithm based on oversampling improved the effective resolution of the system. Validation experiments show that the minimum bioimpedance deviation measured in the experiment can reach 1 Ω even when the bioimpedance baseline is 10 kΩ and the noise level is low. The system has advantages of high resolution, high magnification, large dynamic range, and good self-adaptability for bioimpedance deviation detection.

  13. A new model analysis of the third harmonic voltage in inductive measurement for critical current density of superconducting films

    Institute of Scientific and Technical Information of China (English)

    Zhang Xu; Wu Zhi-Zhen; Zhou Tie-Ge; He Ming; Zhao Xin-Jie; Yan Shao-Lin; Fang Lan

    2011-01-01

    The critical current density Jc is one of the most important parameters of high temperature superconducting films in superconducting applications, such as superconducting filter and superconducting Josephson devices. This paper presents a new model to describe inhomogeneous current distribution throughout the thickness of superconducting films applying magnetic field by solving the differential equation derived from Maxwell equation and the second London equation. Using this model, it accurately calculates the inductive third-harmonic voltage when the film applying magnetic field with the inductive measurement for Jc. The theoretic curve is consistent with the experimental results about measuring superconducting film, especially when the third-harmonic voltage just exceeds zero. The Jc value of superconducting films determined by the inductive method is also compared with results measured by four-probe transport method. The agreements between inductive method and transport method are very good.

  14. Design of an Integrated Thermoelectric Generator Power Converter for Ultra-Low Power and Low Voltage Body Energy Harvesters aimed at EEG/ECG Active Electrodes

    Science.gov (United States)

    Ataei, Milad; Robert, Christian; Boegli, Alexis; Farine, Pierre-André

    2014-11-01

    This paper describes a design procedure for an efficient body thermal energy harvesting integrated power converter. This procedure is based on loss examination for a selfpowered medical device. All optimum system parameters are calculated respecting the transducer constraints and the application form factor. It is found that it is possible to optimize converter's working frequency with proper design of its pulse generator circuit. At selected frequency, it has been demonstrated that wide area voltage doubler can be eliminated at the expense of wider switches. With this method, more than 60% efficiency is achieved in simulation for just 20mV transducer output voltage and 30% of entire chip area is saved.

  15. Mechanical measurements on lithium phosphorous oxynitride coated silicon thin film electrodes for lithium-ion batteries during lithiation and delithiation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Obeidi, Ahmed, E-mail: alobeidi@mit.edu; Thompson, Carl V., E-mail: reiner.moenig@kit.edu, E-mail: cthomp@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Kramer, Dominik, E-mail: dominik.kramer@kit.edu; Mönig, Reiner, E-mail: reiner.moenig@kit.edu, E-mail: cthomp@mit.edu [Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), Helmholtzstraße 11, 89081 Ulm (Germany); Boles, Steven T., E-mail: steven.t.boles@polyu.edu.hk [Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Hong Kong Polytechnic University, 11 Yuk Choi Rd, Hung Hom (Hong Kong)

    2016-08-15

    The development of large stresses during lithiation and delithiation drives mechanical and chemical degradation processes (cracking and electrolyte decomposition) in thin film silicon anodes that complicate the study of normal electrochemical and mechanical processes. To reduce these effects, lithium phosphorous oxynitride (LiPON) coatings were applied to silicon thin film electrodes. Applying a LiPON coating has two purposes. First, the coating acts as a stable artificial solid electrolyte interphase. Second, it limits mechanical degradation by retaining the electrode's planar morphology during cycling. The development of stress in LiPON-coated electrodes was monitored using substrate curvature measurements. LiPON-coated electrodes displayed highly reproducible cycle-to-cycle behavior, unlike uncoated electrodes which had poorer coulombic efficiency and exhibited a continual loss in stress magnitude with continued cycling due to film fracture. The improved mechanical stability of the coated silicon electrodes allowed for a better investigation of rate effects and variations of mechanical properties during electrochemical cycling.

  16. Using a sensitivity study to facilitate the design of a multi-electrode array to measure six cardiac conductivity values.

    Science.gov (United States)

    Johnston, Barbara M

    2013-07-01

    When using the bidomain model to model the electrical activity of the heart, there are potentially six cardiac conductivity values involved: conductivity values in directions along and normal to the cardiac fibres with a sheet, as well as a conductivity value in the normal direction between the sheets, and these occur for both the extracellular and intracellular domains in the model. To date it has been common to assume that the two normal direction conductivity values are the same. However, recent work has demonstrated that six cardiac conductivity values, rather than four, are necessary for accurate modelling, which can then facilitate understanding of cardiovascular disease. To design a method to determine these conductivities, it is also necessary to design a suitable multi-electrode array, which can be used, in conjunction with an inversion technique, to retrieve conductivity values from measurements of potential made on the array. This work uses the results of a study, into the sensitivity of the measuring potentials to variability in the input conductivities, to facilitate the design of an array that could be used to retrieve six cardiac conductivity values, as well as fibre rotation angle. It is found that if an electrode in the array has a much lower value of potential than the other electrodes, then it tends to be much more sensitive to the input conductivities than the other electrodes. It also appears that inclusion of this type of electrode in the set of measuring electrodes is essential for accurately retrieving conductivity values. This technique is used to identify electrodes to be included in the array and using the final design it is demonstrated, using synthetic values of potential, that the six cardiac conductivity values, and the fibre rotation angle, can be retrieved very accurately.

  17. Ultra-low power sensor for autonomous non-invasive voltage measurement in IoT solutions for energy efficiency

    Science.gov (United States)

    Villani, Clemente; Balsamo, Domenico; Brunelli, Davide; Benini, Luca

    2015-05-01

    Monitoring current and voltage waveforms is fundamental to assess the power consumption of a system and to improve its energy efficiency. In this paper we present a smart meter for power consumption which does not need any electrical contact with the load or its conductors, and which can measure both current and voltage. Power metering becomes easier and safer and it is also self-sustainable because an energy harvesting module based on inductive coupling powers the entire device from the output of the current sensor. A low cost 32-bit wireless CPU architecture is used for data filtering and processing, while a wireless transceiver sends data via the IEEE 802.15.4 standard. We describe in detail the innovative contact-less voltage measurement system, which is based on capacitive coupling and on an algorithm that exploits two pre-processing channels. The system self-calibrates to perform precise measurements regardless the cable type. Experimental results demonstrate accuracy in comparison with commercial high-cost instruments, showing negligible deviations.

  18. Decomposition of Composite Electric Field in a Three-Phase D-Dot Voltage Transducer Measuring System

    Directory of Open Access Journals (Sweden)

    Xueqi Hu

    2016-10-01

    Full Text Available In line with the wider application of non-contact voltage transducers in the engineering field, transducers are required to have better performance for different measuring environments. In the present study, the D-dot voltage transducer is further improved based on previous research in order to meet the requirements for long-distance measurement of electric transmission lines. When measuring three-phase electric transmission lines, problems such as synchronous data collection and composite electric field need to be resolved. A decomposition method is proposed with respect to the superimposed electric field generated between neighboring phases. The charge simulation method is utilized to deduce the decomposition equation of the composite electric field and the validity of the proposed method is verified by simulation calculation software. With the deduced equation as the algorithm foundation, this paper improves hardware circuits, establishes a measuring system and constructs an experimental platform for examination. Under experimental conditions, a 10 kV electric transmission line was tested for steady-state errors, and the measuring results of the transducer and the high-voltage detection head were compared. Ansoft Maxwell Stimulation Software was adopted to obtain the electric field intensity in different positions under transmission lines; its values and the measuring values of the transducer were also compared. Experimental results show that the three-phase transducer is characterized by a relatively good synchronization for data measurement, measuring results with high precision, and an error ratio within a prescribed limit. Therefore, the proposed three-phase transducer can be broadly applied and popularized in the engineering field.

  19. Development of New Electrode System for High Field Dielectric Properties Measurement Using Evaporated Polypropylene Thin Guard Film

    Science.gov (United States)

    Fujii, Masayuki; Tohyama, Kazuyuki; Tokoro, Tetsuro; Mizuno, Yukio; Nagao, Masayuki; Kosaki, Masamitsu

    Non-polar polymers such as polyethylene (PE) and polypropylene (PP) are widely used as very important electrical insulating and dielectric materials. They are used in the increasingly high AC electric field strength region approaching to the limit of electrical breakdown strength of the materials. Therefore the study of high-field dielectric property is very important in terms of understanding the AC breakdown mechanism of materials. A three-terminals electrode system with a guard film (new type electrode system) was developed in our laboratory for the precise measurement of high-field tanδ, where the guard film was used to reduce the disturbance of electric field around the edge of a main electrode. However, minute air sometimes steals between a sample film and the guard film. The air sometimes generates partial discharge in the high electric field region. Therefore, when the sample had minute air, the new type electrode system was limited under 100kVrms/mm application that didn't reach to an intrinsic breakdown strength of the 30μm-thick sample. We tried to improve the new electrode system without minute air between a sample film and the guard film. We also tried to make very thin guard film to reduce the field disturbance at the edge of main electrode. In this paper a PP-guard film on a biaxially oriented polypropylene (BOPP) film was made by evaporation. This improvement of the electrode system using the evaporated PP-guard film was in success so that high-field dielectric properties of BOPP film could be measured up to near the intrinsic breakdown field of the sample.

  20. Microfluidic Device to Measure the Speed of C. elegans Using the Resistance Change of the Flexible Electrode

    Directory of Open Access Journals (Sweden)

    Jaehoon Jung

    2016-03-01

    Full Text Available This work presents a novel method to assess the condition of Caenorhabditis elegans (C. elegans through a resistance measurement of its undulatory locomotion speed inside a micro channel. As the worm moves over the electrode inside the micro channel, the length of the electrode changes, consequently behaving like a strain gauge. In this paper, the electrotaxis was applied for controlling the direction of motion of C. elegans as an external stimulus, resulting in the worm moving towards the cathode of the circuit. To confirm the proposed measurement method, a microfluidic device was developed that employs a sinusoidal channel and a thin polydimethylsiloxane (PDMS layer with an electrode. The PDMS layer maintains a porous structure to enable the flexibility of the electrode. In this study, 6 measurements were performed to obtain the speed of an early adult stage C. elegans, where the measured average speed was 0.35 (±0.05 mm/s. The results of this work demonstrate the application of our method to measure the speed of C. elegans undulatory locomotion. This novel approach can be applied to make such measurements without an imaging system, and more importantly, allows directly to detect the locomotion of C. elegans using an electrical signal (i.e., the change in resistance.

  1. Broadband electromagnetic characterization of a 100  Ω traveling-wave electrode by measuring scattering parameters

    Directory of Open Access Journals (Sweden)

    Fabrizio Consoli

    2013-07-01

    Full Text Available The Single Bunch Selector (SBS will be used on the Spiral2 linear accelerator to reduce the rate of high energy bunches reaching the target with, in principle, no residual particles from the suppressed bunches. For this purpose, a pulsed electromagnetic wave will travel along the 100  Ω microstrip meander line electrode of the SBS. In this work we describe the broadband accurate characterization of the electrode electromagnetic features. The method applied here leads to the analytical determination of complex characteristic impedance, propagation constant, and group velocity from a measurement of the 50  Ω scattering parameters on the meander transmission line. Particular care is given to the de-embedding phase of the transitions required to connect the meander electrode to the measurement device.

  2. High voltage surface potential measurements in ambient conditions: Application to organic thin-film transistor injection and transport characterization

    Science.gov (United States)

    de Tournadre, Grégoire; Reisdorffer, Frédéric; Rödel, Reinhold; Simonetti, Olivier; Klauk, Hagen; Giraudet, Louis

    2016-03-01

    A scanning surface potential measurement technique suited for thin-film devices operating under high voltages is reported. A commercial atomic force microscope has been customized to enable a feedback-controlled and secure surface potential measurement based on phase-shift detection under ambient conditions. Measurements of the local potential profile along the channel of bottom-gate organic thin-film transistors (TFTs) are shown to be useful to disentangle the contributions from the channel and contacts to the device performance. Intrinsic contact current-voltage characteristics have been measured on bottom-gate, top-contact (staggered) TFTs based on the small-molecule semiconductor dinaphtho[2,3-b:2',3-f]thieno[3,2-b]thiophene (DNTT) and on bottom-gate, bottom-contact (coplanar) TFTs based on the semiconducting polymer polytriarylamine (PTAA). Injection has been found to be linear in the staggered DNTT TFTs and nonlinear in the coplanar PTAA TFTs. In both types of TFT, the injection efficiency has been found to improve with increasing gate bias in the accumulation regime. Contact resistances as low as 130 Ω cm have been measured in the DNTT TFTs. A method that eliminates the influence of bias-stress-induced threshold-voltage shifts when measuring the local charge-carrier mobility in the channel is also introduced, and intrinsic channel mobilities of 1.5 cm2 V-1 s-1 and 1.1 × 10-3 cm2 V-1 s-1 have been determined for DNTT and PTAA. In both semiconductors, the mobility has been found to be constant with respect to the gate bias. Despite its simplicity, the Kelvin probe force microscopy method reported here provides robust and accurate surface potential measurements on thin-film devices under operation and thus paves the way towards more extensive studies of particular interest in emerging fields of solid-state electronics.

  3. Research and Experiments on a Unipolar Capacitive Voltage Sensor

    Directory of Open Access Journals (Sweden)

    Qiang Zhou

    2015-08-01

    Full Text Available Voltage sensors are an important part of the electric system. In service, traditional voltage sensors need to directly contact a high-voltage charged body. Sensors involve a large volume, complex insulation structures, and high design costs. Typically an iron core structure is adopted. As a result, ferromagnetic resonance can occur easily during practical application. Moreover, owing to the multilevel capacitor divider, the sensor cannot reflect the changes of measured voltage in time. Based on the electric field coupling principle, this paper designs a new voltage sensor; the unipolar structure design solves many problems of traditional voltage sensors like the great insulation design difficulty and high costs caused by grounding electrodes. A differential signal input structure is adopted for the detection circuit, which effectively restrains the influence of the common-mode interference signal. Through sensor modeling, simulation and calculations, the structural design of the sensor electrode was optimized, miniaturization of the sensor was realized, the voltage division ratio of the sensor was enhanced, and the phase difference of sensor measurement was weakened. The voltage sensor is applied to a single-phase voltage class line of 10 kV for testing. According to the test results, the designed sensor is able to meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as to provide a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system. Therefore, it can satisfy the development demands of the smart power grid.

  4. Measurement of labile copper in wine by medium exchange stripping potentiometry utilising screen printed carbon electrodes.

    Science.gov (United States)

    Clark, Andrew C; Kontoudakis, Nikolaos; Barril, Celia; Schmidtke, Leigh M; Scollary, Geoffrey R

    2016-07-01

    The presence of copper in wine is known to impact the reductive, oxidative and colloidal stability of wine, and techniques enabling measurement of different forms of copper in wine are of particular interest in understanding these spoilage processes. Electrochemical stripping techniques developed to date require significant pretreatment of wine, potentially disturbing the copper binding equilibria. A thin mercury film on a screen printed carbon electrode was utilised in a flow system for the direct analysis of labile copper in red and white wine by constant current stripping potentiometry with medium exchange. Under the optimised conditions, including an enrichment time of 500s and constant current of 1.0μA, the response range was linear from 0.015 to 0.200mg/L. The analysis of 52 red and white wines showed that this technique generally provided lower labile copper concentrations than reported for batch measurement by related techniques. Studies in a model system and in finished wines showed that the copper sulfide was not measured as labile copper, and that loss of hydrogen sulfide via volatilisation induced an increase in labile copper within the model wine system.

  5. Diaphragm compound muscle action potential measured with magnetic stimulation and chest wall surface electrodes.

    Science.gov (United States)

    Luo, Y M; Mustfa, N; Lyall, R A; Man, W D C; Glérant, J C; Polkey, M I; Moxham, J

    2002-06-01

    To seek a method to reliably measure phrenic nerve conduction time (PNCT) with magnetic stimulation we investigated two stimulus sites, placing the magnetic coil at the cricoid cartilage (high position) or close to the clavicle (low position). We also compared compound muscle action potential (CMAP) recorded from three different sites: in the sixth to eighth intercostal spaces in the anterior axillary line (Ant-a); in the 8th intercostal space close to the midclavicular line; and with one electrode at the lower sternum and the other at the costal margin. Fourteen normal subjects were studied. The PNCT measured by magnetic stimulation in the high position recorded from (Ant-a) was 7.6+/-0.6 on the left side and 8.4+/-0.7 on the right. The PNCT recorded from all three sites become much shorter when the magnetic coil was moved from the high to the low position. Our results show that PNCT can be accurately measured with magnetic stimulation when care is taken to avoid coactivation of the brachial plexus.

  6. Measurements of Rotational Temperatures in Atmospheric-Pressure Capillary Plasma Electrode (CPE) Discharge

    Science.gov (United States)

    Figus, Margaret; Abramzon, Nina; Becker, Kurt

    2003-10-01

    We report the results of rotational temperature measurements in atmospheric-pressure capillary plasma electrode (CPE) discharges in ambient air using the unresolved N2 second positive band. Assuming that the emitting N2 molecules can be described by a Maxwell-Boltzmann distribution characterized by a single rotational temperature, this temperature is determined from a fit of the measured emission spectrum to a calculated spectrum. If the emitting species are in equilibrium with the bulk gas in the plasma, then this temperature can be interpreted as the gas kinetic temperature in the plasma. We determined rotational temperatures for three different plasma regions: inside the capillary by analyzing radiation emitted along the axis of the capillary, between the capillaries, and perpendicular to the axis of the capillary. Each region has a different plasma density and, therefore, a different gas temperature with the plasma inside the capillary being the hottest. We also measured the rotational temperatures in each region as a function of the plasma power. As expected, the rotational temperatures increase with increasing discharge power. Work supported by the NSF and by ARO through a DURIP award.

  7. ELECTRODE MEASUREMENT OF REDOX POTENTIAL IN ANAEROBIC FERRIC/FERROUS CHLORIDE SYSTEMS

    Science.gov (United States)

    The behaviour of two inert redox electrodes (Pt and wax-impregnated graphite) was investigated in anaerobic ferrous and ferric chloride solutions in order to establish if these electrodes respond to the Fe3+/Fe2+ couple in a Nernstian manner. A new method fo...

  8. Flow reversal at low voltage and low frequency in a microfabricated ac electrokinetic pump

    DEFF Research Database (Denmark)

    Gregersen, Misha Marie; Olesen, Laurits Højgaard; Brask, Anders

    2007-01-01

    Microfluidic chips have been fabricated in Pyrex glass to study electrokinetic pumping generated by a low-voltage ac bias applied to an in-channel asymmetric metallic electrode array. A measurement procedure has been established and followed carefully resulting in a high degree of reproducibility...... of the measurements over several days. A large coverage fraction of the electrode array in the microfluidic channels has led to an increased sensitivity allowing for pumping measurements at low bias voltages. Depending on the ionic concentration a hitherto unobserved reversal of the pumping direction has been...

  9. Impedance measurements of self-assembled lipid bilayer membranes on the tip of an electrode.

    Science.gov (United States)

    Bordi, F; Cametti, Cesare; Gliozzi, A

    2002-07-01

    Supported lipid membranes were self-assembled on the tip of a freshly cleaved silver wire, in the presence of an appropriate polarization voltage, to facilitate, during the membrane formation, the organization of the lipids into an ordered structure. Radiowave impedance spectroscopy measurements have been carried out to provide information on the relaxation properties of the system. We have measured the conductometric and dielectric properties of bilayers built up of different lipids [dipalmitoylphosphatidic acid (DPPA), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), linoleic acid (LIN)] in a wide frequency range (from 10(3) to 10(6) Hz) and in electrolyte solutions of different ionic strengths, in the presence of uni-univalent (KCl) and di-univalent (CaCl(2), MgCl(2), ZnCl(2)) electrolytes. This made it possible to measure the influence of different cations and different lipid compositions on the membrane properties. In particular, we have found a different capacitive behaviour of the supported lipid bilayer membrane (s-BLM) structure in the presence of different counterions in the electrolyte solution. This peculiarity offers the opportunity for the preparation of a variety of biosensors with diverse applications in membrane biophysics, biochemistry and biotechnology.

  10. Enhanced low current, voltage, and power dissipation measurements via Arduino Uno microcontroller with modified commercially available sensors

    Science.gov (United States)

    Tanner, Meghan; Eckel, Ryan; Senevirathne, Indrajith

    The versatility, simplicity, and robustness of Arduino microcontroller architecture have won a huge following with increasingly serious engineering and physical science applications. Arduino microcontroller environment coupled with commercially available sensors have been used to systematically measure, record, and analyze low currents, low voltages and corresponding dissipated power for assessing secondary physical properties in a diverse array of engineering systems. Setup was assembled via breadboard, wire, and simple soldering with an Arduino Uno with ATmega328P microcontroller connected to a PC. The microcontroller was programmed with Arduino Software while the bootloader was used to upload the code. Commercial Hall effect current sensor modules ACS712 and INA169 current shunt monitor was used to measure corresponding low to ultra-low currents and voltages. Stable measurement data was obtained via sensors and compared with corresponding oscilloscope measurements to assess reliability and uncertainty. Sensor breakout boards were modified to enhance the sensitivity of the measurements and to expand the applicability. Discussion of these measurements will focus on capabilities, capacities and limitations of the systems with examples of possible applications. Lock Haven Nanotechnology Program.

  11. Hysteresis observed in quasi open-circuit voltage measurements of lithium insertion in hydrogen-containing carbons

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Tao; Dahn, J.R. [Dalhousie Univ., Halifax, NS (Canada). Dept. of Physics

    1997-10-01

    High capacities with large hysteresis were observed during lithium insertion in hydrogen-containing carbons heated at temperatures near 700 C. Quasi open-circuit voltage (OCV) measurements were used to study these materials. Using a simple model developed previously, we can qualitatively model the result of the OCV measurement. It is believed that the lithium atoms bind near aromatic hydrogen at edge of each graphene layer in the materials. This activated process involves a carbon-carbon bonding change from (sp){sup 2} to (sp){sup 3} leading to large hysteresis during lithium insertion. (orig.)

  12. Determining the mobility of ions by transient current measurements at high voltages.

    Science.gov (United States)

    Kohn, Peter; Schröter, Klaus; Thurn-Albrecht, Thomas

    2007-08-24

    We present polarization and transient current experiments that allow an independent determination of the charge carrier density and the mobility of ions in polymer electrolytes at low charge carrier density. The method relies on a complete depletion of ions in the bulk electrolyte achieved by applying high voltages. Based on a qualitative model for the charge dynamics in this nonlinear regime, the method is exemplarily applied to a system of polymethylmethacrylate doped with small amounts of a lithium salt. The independently obtained values for the ionic mobility, the charge carrier density, and the conductivity are consistent for all salt concentrations studied. Criteria for the applicability of the method are discussed.

  13. Measurements of gas pressure in voids in epoxy castings for high voltage equipment

    DEFF Research Database (Denmark)

    Larsen, Esben; Henriksen, Mogens; Nielsen, E

    1988-01-01

    the partial-discharge inception voltage. Data show that gas pressure in voids in epoxy castings can be determined by use of an ultrasound test method. A relationship between the void gas pressure and the epoxy curing pressure is also found. This investigation is part of an effort to predict the inception......An investigation of samples of epoxy each containing one void, which were produced at different pressures, is reported. The samples were of the disk type with the void located in the center. The gas in the voids has a pressure somewhat related to the curing pressure, thereby directly influencing...

  14. Ammonia measurement with a pH electrode in the ammonia/urea-SCR process

    Science.gov (United States)

    Kröcher, Oliver; Elsener, Martin

    2007-03-01

    The selective catalytic reduction of nitrogen oxides with ammonia (ammonia SCR) and urea (urea SCR), respectively, is a widespread process to clean flue and diesel exhaust gases due to its simplicity and efficiency. The main challenge of the process is to minimize the ammonia emissions downstream of the SCR catalyst. We found that ammonia emissions of >10 ppm can reliably be detected with a simple pH electrode in the presence of CO2, SOx, NOx, and moderately weak organic acids. 10-20 ppm of ammonia in the exhaust gas are sufficient to neutralize the acids and to increase the pH value from 3 to 6. On this basis a continuous measuring method for ammonia was developed, which was used to control the dosage of urea in the SCR process. While keeping the ammonia emissions after the SCR catalyst at 5-30 ppm an average NOx removal efficiency (DeNOx) of >95% were achieved at a diesel test rig. The method can also be applied for exhaust gases with higher acid contents, if a basic pre-filter is added adsorbing the acidic exhaust components. Compared to water as absorption solution, more precise ammonia measurements are possible, if a 0.1 M NH4Cl absorption solution is applied, whose pH value is changing as a Nernst function of the ammonia concentration.

  15. The concept of floating electrode for contact-less electrochemical measurements: Application to reinforcing steel-bar corrosion in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Keddam, M. [LISE, UPR 15 du CNRS, Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05 (France); Novoa, X.R. [E.T.S.E.I, Universidade de Vigo, Campus Universitario, 36310 Vigo (Spain); Vivier, V. [LISE, UPR 15 du CNRS, Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05 (France)], E-mail: vincent.vivier@upmc.fr

    2009-08-15

    The concept of floating electrode is introduced for defining the common electrochemical behaviour of any non-connected, electronically conducting, body immersed in an electrolytic medium. The emphasis is put on both its own polarisation features and its influence on the d.c. and a.c. current and potential across the cell, hence the feasibility, among others, of contact-less electrochemical measurements on floating electrodes. Application to reinforcing steel bars in concrete is investigated by numerical computation of the a.c. current and potential fields in a broad range of concrete resistivity, interfacial resistance and capacitance. Impedance defined in a 4-electrode configuration, when rationalised against the concrete resistivity, is shown to provide, within a realistic range of parameters, a practical mean to access the properties of the bar-concrete interface.

  16. Direct measurement of voltage-controlled reversal of the antiferromagnetic spin structure in magnetoelectric Cr2O3

    Science.gov (United States)

    Wang, Junlei; Binek, Christian

    The frequency dependence of the electric field induced magneto-optical Faraday effect is investigated in the magnetoelectric antiferromagnet chromia. Two electrically induced Faraday signals superimpose in proportion to the linear magnetoelectric susceptibility and the antiferromagnetic order parameter. The relative strength of these contributions is determined by the frequency of the probing light beam. It allows tuning the Faraday signal between extreme characteristics which follow the temperature dependence of the magnetoelectric susceptibility or solely that of the antiferromagnetic order parameter. The frequency dependence is analyzed in terms of electric dipole transitions of perturbed Cr3 + crystal-field states. The results lead to a table-top set-up allowing to measure voltage-controlled selection and temperature dependence of the antiferromagnetic order parameter. The Faraday rotation per applied voltage is independent of the sample thickness making the method scalable and versatile for thin film investigations. Scalability, compactness, and simplicity of the data analysis combined with low photon flux requirements make the Faraday approach advantageous for the investigation of the otherwise difficult to access voltage-controlled switching of antiferromagnetic domain states in magnetoelectric thin films. This project is supported by NRI via CNFD through tasks SRC 2398.001 and 2587.001, by C-SPIN, a SRC program, sponsored by MARCO and DARPA, and by NSF through Nebraska MRSEC DMR-1420645.

  17. Benchmarking of 3D space charge codes using direct phase space measurements from photoemission high voltage dc gun

    Directory of Open Access Journals (Sweden)

    Ivan V. Bazarov

    2008-10-01

    Full Text Available We present a comparison between space charge calculations and direct measurements of the transverse phase space of space charge dominated electron bunches from a high voltage dc photoemission gun followed by an emittance compensation solenoid magnet. The measurements were performed using a double-slit emittance measurement system over a range of bunch charge and solenoid current values. The data are compared with detailed simulations using the 3D space charge codes GPT and Parmela3D. The initial particle distributions were generated from measured transverse and temporal laser beam profiles at the photocathode. The beam brightness as a function of beam fraction is calculated for the measured phase space maps and found to approach within a factor of 2 the theoretical maximum set by the thermal energy and the accelerating field at the photocathode.

  18. Effect of precordial electrocardiographic electrode placement on ST-segment measurement during exercise.

    Science.gov (United States)

    Bertolet, B D; Boyette, A F; Mardis, M; Hill, J A

    1995-04-01

    Research protocols often utilize serial exercise testing to examine the efficacy of anti-ischemic therapies. These tests, however, are prone to multiple sources of bias. This investigation sought to determine the influence of varying precordial electrocardiographic (ECG) electrode placement on the detection of exercise-induced ST-segment shifts. Fifteen coronary artery disease patients with abnormal exercise tests were studied. Based on the previous exercise test, the precordial electrode position exhibiting the greatest ST-segment shift was selected as the reference electrode. Four additional electrodes were placed around this reference electrode and exercise testing was performed. ECG strips were recorded every minute. The time-to-onset and -offset of ischemic-type ST-segment depression was recorded. ST-segment depression was recorded during exercise from the reference electrode in 12 of 15 patients. Ischemic-type ST-depression was also recorded in each of these 12 patients with the surrounding electrodes; however, the time-to-onset detected by all four surrounding electrodes concurred in only 5 of 12 (42%) patients. The time-to-offset of the ST-segment depression concurred in 9 of 12 (75%) patients. Serial ECGs recorded from similar but not exactly the same precordial ECG electrode position should yield similar results for the detection of ischemia, but time-to-onset or -offset of ischemia may differ by 60 s or more. Small changes in the time-to-onset and -offset of ischemia should not be considered reliable indicators of anti-ischemia efficacy.

  19. Near-wall measurements of the bubble- and Lorentz-force-driven convection at gas-evolving electrodes

    Science.gov (United States)

    Baczyzmalski, Dominik; Weier, Tom; Kähler, Christian J.; Cierpka, Christian

    2015-08-01

    Chemical energy storage systems, e.g., in the form of hydrogen or methanol, have a great potential for the establishment of volatile renewable energy sources due to the large energy density. The efficiency of hydrogen production through water electrolysis is, however, limited by gas bubbles evolving at the electrode's surface and can be enhanced by an accelerated bubble detachment. In order to characterize the complex multi-phase flow near the electrode, simultaneous measurements of the fluid velocities and the size and trajectories of hydrogen bubbles were performed in a water electrolyzer. The liquid phase velocity was measured by PIV/PTV, while shadowgraphy was used to determine the bubble trajectories. Special measurement and evaluation techniques had to be applied as the measurement uncertainty is strongly affected by the high void fraction close to the wall. In particular, the application of an advanced PTV scheme allowed for more precise fluid velocity measurements closer to electrode. Based on these data, stability characteristics of the near-wall flow were evaluated and compared to that of a wall jet. PTV was used as well to investigate the effect of Lorentz forces on the near-wall fluid velocities. The results show a significantly increased wall parallel liquid phase velocity with increasing Lorentz forces. It is presumed that this enhances the detachment of hydrogen bubbles from the electrode surface and, consequently, decreases the fractional bubble coverage and improves the efficiency. In addition, the effect of large rising bubbles with path oscillations on the near-wall flow was investigated. These bubbles can have a strong impact on the mass transfer near the electrode and thus affect the performance of the process.

  20. Space charge inhibition effect of nano-Fe{sub 3}O{sub 4} on improvement of impulse breakdown voltage of transformer oil based on improved Kerr optic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qing, E-mail: yangqing@cqu.edu.cn; Yu, Fei; Sima, Wenxia [State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Shapingba District, Chongqing, 400044 (China); Zahn, Markus [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2015-09-15

    Transformer oil-based nanofluids (NFs) with 0.03 g/L Fe{sub 3}O{sub 4} nanoparticle content exhibit 11.2% higher positive impulse breakdown voltage levels than pure transformer oils. To study the effects of the Fe{sub 3}O{sub 4} nanoparticles on the space charge in transformer oil and to explain why the nano-modified transformer oil exhibits improved impulse breakdown voltage characteristics, the traditional Kerr electro-optic field mapping technique is improved by increasing the length of the parallel-plate electrodes and by using a photodetector array as a high light sensitivity device. The space charge distributions of pure transformer oil and of NFs containing Fe{sub 3}O{sub 4} nanoparticles can be measured using the improved Kerr electro-optic field mapping technique. Test results indicate a significant reduction in space charge density in the transformer oil-based NFs with the Fe{sub 3}O{sub 4} nanoparticles. The fast electrons are captured by the nanoparticles and are converted into slow-charged particles in the NFs, which then reduce the space charge density and result in a more uniform electric field distribution. Streamer propagation in the NFs is also obstructed, and the breakdown strengths of the NFs under impulse voltage conditions are also improved.

  1. Extraction of a strongly focusing He+ beam from three-stage concave electrodes for alpha particle measurement system in ITER.

    Science.gov (United States)

    Kobuchi, T; Sasao, M; Kisaki, M; Tsumori, K; Tanaka, N; Okamoto, A; Kitajima, S; Kaneko, O; Shinto, K; Wada, M

    2012-02-01

    A strongly focusing He(+) ion beam source equipped with concave multi-aperture electrodes was developed for production of He(-) through a charge exchange cell. The beam was extracted at a voltage less than 20 kV from 301 apertures distributed in an area of 100 mm φ, and focused at 750 mm distance. The beam current and the beam size of 2 A and 20 mm in diameter, respectively, were achieved with an arc power less than 10 kW. The optimum perveance was obtained at 0.02 A∕kV(1.5) at the beam energy less than 20 keV which is suitable for the conversion to He(-) in an alkali vapor cell.

  2. The performance of a NERO 8000 non-invasive x-ray beam analyser when measuring tube voltage under fluoroscopic conditions.

    Science.gov (United States)

    Burrage, J W

    2001-09-01

    A NERO 8000 non-invasive x-ray beam analyser was examined under fluoroscopic conditions with respect to the measurement of tube voltage. An invasive measurement of tube voltage was performed concurrently to test the accuracy of the NERO device over a range of tube voltages and currents. The data indicated that for the NERO 8000 the accuracy of kVp average measurement is dependent on input doserate. With the tube current set to 1 mA the doserates ranged from 2.1 to 6.5 mGy/min over the range of tube voltages measured. The associated kVp average measurement errors ranged from 6 to 28%. At 5 mA the doserates ranged from 20.4 to 66.0 mGy/min and the associated errors ranged from 0 to 3%. A possible explanation for the drop in accuracy of kVp measurements at low doserates is a decreased signal to noise ratio. The kV waveforms from inaccurate measurements appeared noisier than waveforms from more accurate measurements. NERO may be interpreting noise spikes as voltage readings and including them in the kVp average calculations, causing an erroneously high kVp average reading. The data from this experiment suggest that when performing non-invasive measurements of tube voltage accuracy in fluoroscopy mode, the doserate must be taken into consideration.

  3. Generation of Radial Electric Field with Electrode Biasing

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng; PAN Ge-Sheng; WEN Yi-Zhi; YU Chang-Xuan; WAN Shu-De; LIU Wan-Dong; WANG Zhi-Jiang; SUN Xuan

    2001-01-01

    Time and space resolved measurements of the radial electric field (Er) have been conducted during the electrode biasing experiments on the KT-5C tokamak. The suppression of the turbulent transport with the change of Er induced by the biased electrode is observed. It is found that the poloidal flow contributes to the main part of the Er, and the change of the poloidal flow has a lead of about 20μs to the formation of Er. These observations suggest that a radialcurrent, responding to an induced voltage on the electrode, drives a poloidal flow which in turn drives the radial electric field.

  4. Green neighbourhoods in low voltage networks: measuring impact of electric vehicles and photovoltaics on load profiles

    CERN Document Server

    Hattam, Laura

    2016-01-01

    In the near future various types of low-carbon technologies (LCTs) are expected to be widely employed throughout the United Kingdom. However, the effect that these technologies will have at a household level on the existing low voltage (LV) network is still an area of extensive research. We propose an agent based model that estimates the growth of LCTs within local neighbourhoods, where social influence is imposed. Real-life data from a LV network is used that comprises of many socially diverse neighbourhoods. Both electric vehicle uptake and the combined scenario of electric vehicle and photovoltaic adoption are investigated with this data. A probabilistic approach is outlined, which determines lower and upper bounds for the model response at every neighbourhood. This technique is used to assess the implications of modifying model assumptions and introducing new model features. Moreover, we discuss how the calculation of these bounds can inform future network planning decisions.

  5. Benchmarking of 3D space charge codes using direct phase space measurements from photoemission high voltage DC gun

    CERN Document Server

    Bazarov, Ivan V; Gulliford, Colwyn; Li, Yulin; Liu, Xianghong; Sinclair, Charles K; Soong, Ken; Hannon, Fay

    2008-01-01

    We present a comparison between space charge calculations and direct measurements of the transverse phase space for space charge dominated electron bunches after a high voltage photoemission DC gun followed by an emittance compensation solenoid magnet. The measurements were performed using a double-slit setup for a set of parameters such as charge per bunch and the solenoid current. The data is compared with detailed simulations using 3D space charge codes GPT and Parmela3D with initial particle distributions created from the measured transverse and temporal laser profiles. Beam brightness as a function of beam fraction is calculated for the measured phase space maps and found to approach the theoretical maximum set by the thermal energy and accelerating field at the photocathode.

  6. Nanowire electrodes for high-density stimulation and measurement of neural circuits

    OpenAIRE

    Robinson, Jacob T.; Jorgolli, Marsela; Park, Hongkun

    2013-01-01

    Brain-machine interfaces (BMIs) that can precisely monitor and control neural activity will likely require new hardware with improved resolution and specificity. New nanofabricated electrodes with feature sizes and densities comparable to neural circuits may lead to such improvements. In this perspective, we review the recent development of vertical nanowire (NW) electrodes that could provide highly parallel single-cell recording and stimulation for future BMIs. We compare the advantages of t...

  7. Acidity Measurements with the Glass Electrode in H2O-D2O Mixtures

    DEFF Research Database (Denmark)

    Mikkelsen, K.; Nielsen, Sigurd Olaf

    1960-01-01

    to variations in the hydrogen-ion concentration in both solvents in the range between 2 x 10 -2 and 2 x 10 -5 M. The acidity determinations involve standardization and storage of the glass electrode in solutions in HzO and subsequent drying of the glass electrode with mercury before immersing it in the 0.5-ml...... the point of view of extrapolating rate data obtained in HzO-DzO mixtures to pure D2O....

  8. Lowering the Operational Voltage of Single-Layer Polymer Electroluminescent Devices by Using CuOx Modifying Indium-Tin Oxide Electrode

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xin-ran; ZHAO Xin-wen; HU Wen-ping

    2007-01-01

    In this study it is demonstrated that oxygen-plasma-generated CuOx can enhance the holes injection from ITO anode into polymer layer in single-layer polymer EL devices. The possible reason for this enhancement is because the ITO anode modified with CuOx possesses much higher work function than pure ITO anode, which reduces the barrier for hole-injection and further lowers the operational voltage of the polymer EL devices. The work function shift is probable due to the oxygen-plasma-generated CuOx can store more releasable oxygen, and the releasable oxygen in turn changes the oxygen concentration just near ITO surface, which will shift the work function of ITO anode.

  9. Development and Demonstration of Measurement-Time Efficient Methods for Impedance Spectroscopy of Electrode and Sensor Arrays

    OpenAIRE

    Derek Johnson; Matthew Smith; Kevin R. Cooper

    2008-01-01

    The development of impedance-based array devices is hindered by a lack of robust platforms and methods upon which to evaluate and interrogate sensors. One aspect to be addressed is the development of measurement-time efficient techniques for broadband impedance spectroscopy of large electrode arrays. The objective of this work was to substantially increase the low frequency impedance measurement throughput capability of a large channel count array analyzer by developing true parallel measurem...

  10. Measurement of low bit-error-rates of adiabatic quantum-flux-parametron logic using a superconductor voltage driver

    Science.gov (United States)

    Takeuchi, Naoki; Suzuki, Hideo; Yoshikawa, Nobuyuki

    2017-05-01

    Adiabatic quantum-flux-parametron (AQFP) is an energy-efficient superconductor logic. The advantage of AQFP is that the switching energy can be reduced by lowering operation frequencies or by increasing the quality factors of Josephson junctions, while keeping the energy barrier height much larger than thermal energy. In other words, both low energy dissipation and low bit error rates (BERs) can be achieved. In this paper, we report the first measurement results of the low BERs of AQFP logic. We used a superconductor voltage driver with a stack of dc superconducting-quantum-interference-devices to amplify the logic signals of AQFP gates into mV-range voltage signals for the BER measurement. Our measurement results showed 3.3 dB and 2.6 dB operation margins, in which BERs were less than 10-20, for 1 Gbps and 2 Gbps data rates, respectively. While the observed BERs were very low, the estimated switching energy for the 1-Gbps operation was only 2 zJ or 30kBT, where kB is the Boltzmann's constant and T is the temperature. Unlike conventional non-adiabatic logic, BERs are not directly associated with switching energy in AQFP.

  11. A Simple Hydrogen Electrode

    Science.gov (United States)

    Eggen, Per-Odd

    2009-01-01

    This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements…

  12. A Simple Hydrogen Electrode

    Science.gov (United States)

    Eggen, Per-Odd

    2009-01-01

    This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements…

  13. Gas sensing properties of branched carbon nanotube-based structures using a novel low voltage emission.

    Science.gov (United States)

    Darbari, S; Azimi, S; Abdi, Y; Mohajerzadeh, S

    2012-11-01

    Branched carbon nanostructures have been successfully grown on interdigital comb-like structures for a gas sensing application. Field emission scanning electron microscopy has been utilized to investigate the morphology and structure of the grown nanostructures at different stages of growth process. Tunneling current of the fabricated sensor has been measured when a monotonically increasing voltage is applied between the electrodes. The effect of exposure to three different gases on the measured current has been studied. A data processing on the measured current voltage characteristics results in the evolution of various peaks at distinct voltages which depends on the type of the gas.

  14. Conductive polymer foam surface improves the performance of a capacitive EEG electrode.

    Science.gov (United States)

    Baek, Hyun Jae; Lee, Hong Ji; Lim, Yong Gyu; Park, Kwang Suk

    2012-12-01

    In this paper, a new conductive polymer foam-surfaced electrode was proposed for use as a capacitive EEG electrode for nonintrusive EEG measurements in out-of-hospital environments. The current capacitive electrode has a rigid surface that produces an undefined contact area due to its stiffness, which renders it unable to conform to head curvature and locally isolates hairs between the electrode surface and scalp skin, making EEG measurement through hair difficult. In order to overcome this issue, a conductive polymer foam was applied to the capacitive electrode surface to provide a cushioning effect. This enabled EEG measurement through hair without any conductive contact with bare scalp skin. Experimental results showed that the new electrode provided lower electrode-skin impedance and higher voltage gains, signal-to-noise ratios, signal-to-error ratios, and correlation coefficients between EEGs measured by capacitive and conventional resistive methods compared to a conventional capacitive electrode. In addition, the new electrode could measure EEG signals, while the conventional capacitive electrode could not. We expect that the new electrode presented here can be easily installed in a hat or helmet to create a nonintrusive wearable EEG apparatus that does not make users look strange for real-world EEG applications.

  15. New method evaluating currents keeping the voltage constant for fast and highly resolved measurement of Arrhenius relation and capacity fade

    Science.gov (United States)

    Lewerenz, Meinert; Käbitz, Stefan; Knips, Marcus; Münnix, Jens; Schmalstieg, Johannes; Warnecke, Alexander; Sauer, Dirk Uwe

    2017-06-01

    The evaluation of floating currents is a powerful method to characterize capacity fade induced by calendaric aging and enables a highly resolved representation of the Arrhenius relation. The test arrangement is simple and could constitute a cheap alternative to state-of-the-art calendaric aging tests including check-up tests. Therefore the currents to maintain a constant voltage are evaluated. This method is validated by analyzing nine cylindrical 8 Ah LiFePO4|Graphite battery cells during calendaric aging at 25 °C, 40 °C and 60 °C at 3.6 V (100% SOC). The 3.6 V are kept by applying constant voltage while the floating currents are logged. The floating currents correlate with the rate of capacity loss measured during capacity tests. The floating currents reveal to be rather constant at 25 °C, linearly increasing at 40 °C and decreasing from a higher level at 60 °C. Additional tests with three test cells, with the temperature rising from 40 to 60 °C in steps of 5 K, exhibit non-constant currents starting from 50 °C on with high variations amongst the tested cells. Once stored above 50 °C, the cells exhibit increased floating currents compared to the measurement at the same temperature before exceeding 50 °C.

  16. The Effect of Electrode Designs Based on the Anatomical Heart Location for the Non-Contact Heart Activity Measurement.

    Science.gov (United States)

    Gi, Sun Ok; Lee, Young-Jae; Koo, Hye Ran; Lee, Seung Pyo; Lee, Kang-Hwi; Kim, Kyeng-Nam; Kang, Seung-Jin; Lee, Joo Hyeon; Lee, Jeong-Whan

    2015-12-01

    This research is an extension of a previous research [1] on the different effects of sensor location that is relatively suitable for heart rate sensing. This research aimed to elucidate the causes of wide variations in heart rate measurements from the same sensor position among subjects, as observed in previous research [1], and to enhance designs of the inductive textile electrode to overcome these variations. To achieve this, this study comprised two parts: In part 1, X-ray examinations were performed to determine the cause of the wide variations noted in the findings from previous research [1], and we found that at the same sensor position, the heart activity signal differed with slight differences in the positions of the heart of each subject owing to individual differences in the anatomical heart location. In part 2, three types of dual-loop-type textile electrodes were devised to overcome variations in heart location that were confirmed in part 1 of the study. The variations with three types of sensor designs were compared with that with a single-round type of electrode design, by using computer simulation and by performing a t-test on the data obtained from the experiments. We found that the oval-oval shaped, dual-loop-type textile electrode was more suitable than the single round type for determining morphological characteristics as well as for measuring appropriate heart activity signals. Based on these results, the oval-oval, dual-loop-type was a better inductive textile electrode that more effectively overcomes individual differences in heart location during heart activity sensing based on the magnetic-induced conductivity principle.

  17. Improved heat-responsive electrode for the measurement of electrochemical Peltier heat. The Peltier heat for electrosorption and electrodesorption of oxygen on a platinum electrode in sulfuric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Shigeo; Sumino, M.P.; Yamada, Akifumi

    1985-01-01

    A new plate type electrode with high sensitivity and response to temperature change was made using a thick film thermistor. The electrochemical Peltier heat for the oxygen surface process at a platinized platinum electrode in 0.5 M H/sub 2/SO/sub 4/ solution was measured with this electrode by potentiodynamic and galvanostatic transient techniques. It was demonstrated that the most of Peltier heat is caused by the overpotential due to the irreversible oxygen electrode reaction. That is, a Tafel-type relation between the Peltier heat and the current was confirmed. A step-wise heat change corresponding to consecutive stages of platinum lattice occupation by OH was observed. The amount of heat evolved on PtO formation was apparently larger than that on PtOH formation. The results were compared with those obtained by the voltammetric measurement. (orig.).

  18. Laser-based surface preparation of composite laminates leads to improved electrodes for electrical measurements

    KAUST Repository

    Almuhammadi, Khaled

    2015-10-19

    Electrical impedance tomography (EIT) is a low-cost, fast and effective structural health monitoring technique that can be used on carbon fiber reinforced polymers (CFRP). Electrodes are a key component of any EIT system and as such they should feature low resistivity as well as high robustness and reproducibility. Surface preparation is required prior to bonding of electrodes. Currently this task is mostly carried out by traditional sanding. However this is a time consuming procedure which can also induce damage to surface fibers and lead to spurious electrode properties. Here we propose an alternative processing technique based on the use of pulsed laser irradiation. The processing parameters that result in selective removal of the electrically insulating resin with minimum surface fiber damage are identified. A quantitative analysis of the electrical contact resistance is presented and the results are compared with those obtained using sanding.

  19. Design, modelling and preliminary characterisation of microneedle-based electrodes for tissue electroporation in vivo

    Science.gov (United States)

    O'Mahony, Conor; Houlihan, Ruth; Grygoryev, Konstantin; Ning, Zhenfei; Williams, John; Moore, Tom

    2016-10-01

    We analysed the use of microneedle-based electrodes to enhance electroporation of mouse testis with DNA vectors for production of transgenic mice. Different microneedle formats were developed and tested, and we ultimately used electrodes based on arrays of 500 μm tall microneedles. In a series of experiments involving injection of a DNA vector expressing Green Fluorescent Protein (GFP) and electroporation using microneedle electrodes and a commercially available voltage supply, we compared the performance of flat and microneedle electrodes by measuring GFP expression at various timepoints after electroporation. Our main finding, supported by both experimental and simulated data, is that needles significantly enhanced electroporation of testis.

  20. Experimental Study on Gas Discharge Excited by 60 kHz High Voltage Power Supply with Pin-to-pin Electrode in Atmospheric Air%大气压空气中尖-尖间隙60kHz高压放电实验研究

    Institute of Scientific and Technical Information of China (English)

    许家雨; 章程; 邵涛; 段立伟; 任成燕; 严萍

    2012-01-01

    大气压低温放电等离子体在点火和辅助燃烧方面有着广泛的应用前景。为此,基于60kHz的高频高压电源,利用尖-尖电极的极不均匀场结构,在空气中获得了稳定的大气压辉光放电,通过测量电压电流并拍摄放电图像,分析了放电过程,并计算得到了电极压降和位移电流。间隙击穿前,间隙距离不变时位移电流随着施加电压而呈线性变化;问隙击穿后,电源输出电压不变时间隙放电电压随着间隙距离而呈线性变化。结果表明放电过程经历3种放电模式(电晕放电、火花放电、辉光放电),放电稳定性随着气体体积流量的增大而减小,在气体体积流量〈3L/min时,可以实现稳定辉光放电。相关结果可为等离子体点火和辅助燃烧提供参考。%Atmospheric-pressure non-thermal plasma has been widely used in plasma-induced ignition and plasma- assisted combustion. In this article, stable glow discharge excited by a high frequency and high voltage power supply is obtained with a pin-to-pin electrode geometry, and the discharge process is investigated by the measurement of voltage-current and the discharge images. Furthermore, the voltage drop at the electrodes and the displacement current is calculated. When the air gap is fixed, displacement current linearly changes with the applied voltage before breakdown. After breakdown takes place, the voltage across the gap changes linearly with the air gap when the output voltage of the generator is fixed. The experimental results show that corona spark, and g)ow discharge occurs in the development of the discharge process, respectively. The stability of the discharge decreases as the increase of the air flow, and the glow discharge can be kept when the air flow is below 3 L/rain. The experimental results can be referred in ignition and combustion.

  1. A multi-electrode biomimetic electrolocation sensor

    Science.gov (United States)

    Mayekar, K.; Damalla, D.; Gottwald, M.; Bousack, H.; von der Emde, G.

    2012-04-01

    We present the concept of an active multi-electrode catheter inspired by the electroreceptive system of the weakly electric fish, Gnathonemus petersii. The skin of this fish exhibits numerous electroreceptor organs which are capable of sensing a self induced electrical field. Our sensor is composed of a sending electrode and sixteen receiving electrodes. The electrical field produced by the sending electrode was measured by the receiving electrodes and objects were detected by the perturbation of the electrical field they induce. The intended application of such a sensor is in coronary diagnostics, in particular in distinguishing various types of plaques, which are major causes of heart attack. For calibration of the sensor system, finite element modeling (FEM) was performed. To validate the model, experimental measurements were carried out with two different systems. The physical system was glass tubing with metal and plastic wall insertions as targets. For the control of the experiment and for data acquisition, the software LabView designed for 17 electrodes was used. Different parameters of the electric images were analyzed for the prediction of the electrical properties and size of the inserted targets in the tube. Comparisons of the voltage modulations predicted from the FEM model and the experiments showed a good correspondence. It can be concluded that this novel biomimetic method can be further developed for detailed investigations of atherosclerotic lesions. Finally, we discuss various design strategies to optimize the output of the sensor using different simulated models to enhance target recognition.

  2. Note: Wide-range and high-resolution on-chip delay measurement circuit with low supply-voltage sensitivity for SoC applications

    Science.gov (United States)

    Sheng, Duo; Hung, Yu-Chan

    2016-11-01

    This paper presents an on-chip delay measurement (OCDM) circuit with a wide delay-measurement range, a high delay-measurement resolution and low supply-voltage sensitivity for efficient detection, and diagnosis in the high-performance system-on-chip (SoC). The proposed cascade-stage measurement structure can simultaneously achieve a delay-measurement range of several nanoseconds and a quantization resolution of several picoseconds. The proposed delay-measurement circuit has a high immunity to supply voltage variations without any additional calibration or self-biasing circuit. The delay-measurement range is 5.25 ns with 6 ps resolution; and the average delay resolution variation is 0.41% with ±10% supply voltage variations.

  3. Simultaneous measurement of membrane potential changes in multiple pattern generating neurons using voltage sensitive dye imaging.

    Science.gov (United States)

    Städele, Carola; Andras, Peter; Stein, Wolfgang

    2012-01-15

    Optical imaging using voltage-sensitive dyes (VSDs) is a promising technique for the simultaneous activity recording of many individual neurons. While such simultaneous recordings are critical for the understanding of the integral functionality of neural systems, functional interpretations on a single neuron level are difficult without knowledge of the connectivity of the underlying circuit. Central pattern generating circuits, such as the pyloric and gastric mill circuits in the stomatogastric ganglion (STG) of crustaceans, allow such investigations due to their well-known connectivities and have already contributed much to our understanding of general neuronal mechanisms. Here we present for the first time simultaneous optical recordings of the pattern generating neurons in the STG of two crustacean species using bulk loading of the VSD di-4-ANEPPS. We demonstrate the recording of firing activities and synaptic interactions of the circuit neurons as well as inter-circuit interactions in their functional context, i.e. without artificial stimulation. Neurons could be uniquely identified using simple event-triggered averaging. We tested this technique in two different species of crustaceans (lobsters and crabs), since several crustacean species are used for studying motor pattern generation. The signal-to-noise ratio of the optical signal was high enough in both species to derive phase-relationship between the network neurons, as well as action potentials and excitatory and inhibitory postsynaptic potentials. We argue that imaging of neural networks with identifiable neurons with well-known connectivity, like in the STG, is crucial for the understanding of emergence of network functionality.

  4. Aspects of Metal-YSZ Electrode Kinetics Studied using Model Electrodes

    DEFF Research Database (Denmark)

    Graves, Christopher R.; Ebbesen, Sune; Mogensen, Mogens Bjerg

    2009-01-01

    The electrode kinetics of oxidation and reduction of H2/H2O and CO/CO2 at the metal/yttria stabilized zirconia (YSZ) interface were studied using model metal wire electrodes contacting polished YSZ pellets. The intent was to probe the reaction mechanisms by comparing the same reactions using...... different metals (Ag, Au, Cu, Ni, Pd, and Pt) under identical conditions relevant to fuel cell and electrolysis cell operation (e.g. including 50% H2/H2O and 50% CO/CO2). Impedance spectra were measured at open-circuit voltage and under polarization, and polarization sweeps were performed. The gas...

  5. Electrochemical Impedance Spectroscopic Measurements of Sexithiophene-Effect of the Electrode Nature and the Dopant (CuCl2) Content

    Institute of Scientific and Technical Information of China (English)

    NESSARK,Belkacem; MAOUCHE,Na(i)ma

    2009-01-01

    Electrochemical impedance spectroscopic (EIS) measurements of sexithiophene (6T) were carried out according to the Pt/6T/M sandwich structure configuration,for various electrode materials (M=GC,ITO,Ag,Cu,AI) and for different doping levels of copper chloride (CuCl2).The results demonstrate that two types of charge transport are involved in the redox process at the electrode/6T interface and inside the bulk oligomer.The complex-plane impedance plots obtained for various doping levels of CuCl2 exhibit arc shapes.The charge-transfer resistance measured from the diagrams decreases systematically with the addition of the salt,leading to an increase of the oligothiophene conductivity.

  6. Application of HFCT and UHF Sensors in On-Line Partial Discharge Measurements for Insulation Diagnosis of High Voltage Equipment

    Directory of Open Access Journals (Sweden)

    Fernando Álvarez

    2015-03-01

    Full Text Available Partial discharge (PD measurements provide valuable information for assessing the condition of high voltage (HV insulation systems, contributing to their quality assurance. Different PD measuring techniques have been developed in the last years specially designed to perform on-line measurements. Non-conventional PD methods operating in high frequency bands are usually used when this type of tests are carried out. In PD measurements the signal acquisition, the subsequent signal processing and the capability to obtain an accurate diagnosis are conditioned by the selection of a suitable detection technique and by the implementation of effective signal processing tools. This paper proposes an optimized electromagnetic detection method based on the combined use of wideband PD sensors for measurements performed in the HF and UHF frequency ranges, together with the implementation of powerful processing tools. The effectiveness of the measuring techniques proposed is demonstrated through an example, where several PD sources are measured simultaneously in a HV installation consisting of a cable system connected by a plug-in terminal to a gas insulated substation (GIS compartment.

  7. [Method of measuring spasticity. Studies of 12 cases of spastic patients treated with chronic epidural implanted electrodes].

    Science.gov (United States)

    Rossi, L; Rasella, M; Ubiali, E

    1984-01-01

    The Authors have applied the method for determination of the H reflex, in order to measure the spasticity in a group of patients operated with chronic implantation of epidural electrodes. After a brief discussion about a clinical and neurophysiological problems of the spasticity, they refers the methodologie and results obtained by determination of H/M ratio and H1/H2 curve with double stimulus. They conclude that this method is rather uncertain and useful only at a approximative clinical level.

  8. A dual-energy medical instrument for measurement of x-ray source voltage and dose rate

    Science.gov (United States)

    Ryzhikov, V. D.; Naydenov, S. V.; Volkov, V. G.; Opolonin, O. D.; Makhota, S.; Pochet, T.; Smith, C. F.

    2016-03-01

    An original dual-energy detector and medical instrument have been developed to measure the output voltages and dose rates of X-ray sources. Theoretical and experimental studies were carried out to characterize the parameters of a new scintillator-photodiode sandwich-detector based on specially-prepared zinc selenide crystals in which the low-energy detector (LED) works both as the detector of the low-energy radiation and as an absorption filter allowing the highenergy fraction of the radiation to pass through to the high-energy detector (HED). The use of the LED as a low-energy filter in combination with a separate HED opens broad possibilities for such sandwich structures. In particular, it becomes possible to analyze and process the sum, difference and ratio of signals coming from these detectors, ensuring a broad (up to 106) measurement range of X-ray intensity from the source and a leveling of the energy dependence. We have chosen an optimum design of the detector and the geometry of the component LED and HED parts that allow energy-dependence leveling to within specified limits. The deviation in energy dependence of the detector does not exceed about 5% in the energy range from 30 to 120 keV. The developed detector and instrument allow contactless measurement of the anode voltage of an X-ray emitter from 40 to 140 kV with an error no greater than 3%. The dose rate measurement range is from 1 to 200 R/min. An original medical instrument has passed clinical testing and was recommended for use in medical institutions for X-ray diagnostics.

  9. Voltage dependence property of parameters for human body discharge in air through a small metal rod

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Discharge parameters are measured and calculated in electrostatic discharge (ESD) from charged human body through a small moving handheld metal rod. Correlation study has been performed on discharge parameters with charge voltage as well as approach speed. At charge voltage 800 V, difference of discharge parameters caused by fast and slow approach speed of electrode is found to reach extreme values. To explore the reason for this special case, an analysis with a short-gap ESD model is carried out.

  10. Validation of gas temperature measurements by OES in an atmospheric air glow discharge with water electrode using Rayleigh scattering

    Energy Technology Data Exchange (ETDEWEB)

    Verreycken, T; Van Gessel, A F H; Pageau, A; Bruggeman, P, E-mail: p.j.bruggeman@tue.n [Eindhoven University of Technology, Department of Applied Physics, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2011-04-15

    Rayleigh scattering is used to determine the gas temperature of an atmospheric pressure dc excited glow discharge in air with a water electrode. The obtained temperatures are compared with calculated rotational temperatures measured by optical emission spectroscopy of OH(A-X) and N{sub 2}(C-B). At a current of 15 mA a deviation is found between T{sub rot}(OH) and the gas temperature obtained from Rayleigh scattering of about 1000 K. The gas temperatures obtained from Rayleigh scattering, N{sub 2}(C) and OH(A) in the positive column are, respectively, 2600 {+-} 100 K, 2700 {+-} 150 K and 3600 {+-} 200 K. It is shown that the rotational temperature of N{sub 2}(C) is a reliable measurement of the gas temperature while this is not the case for OH(A). The results are explained in the context of quenching processes of the excited states. Spatially resolved gas temperatures in both longitudinal and radial directions are presented. The observed strong temperature gradients near the electrodes are checked to be consistent with the power dissipation and the heat transfer in the discharge. The effect of the polarity of the water electrode and filamentation on the measured temperatures is discussed.

  11. 外部电压源法测试大电压LED器件/模块热阻%Measuring thermal resistance for high voltage LED device and module by applying ex ternal voltage source

    Institute of Scientific and Technical Information of China (English)

    陈国龙; 朱丽虹; 郭自泉; 张纪红; 吕毅军; 高玉琳; 陈忠

    2013-01-01

    热阻是衡量LED器件/模块散热性能的重要参数。针对大电压LED器件/模块,实验采用 T3Ster/T eraled热光参数测试仪,利用外部电压源供电方法,实现了对超过仪器量程的大电压L ED器件的热阻测试。该方法拓展了热阻测试仪的常规测量范围,使正向电压大于15 V的L ED器件/模块的热阻测试成为可能。%Thermal resistance is a key parameter for evaluating thermal performance of LED device/module . Reliable measurement of thermal resistance becomes extremely important .Aiming at that the high voltage LED device/module has been applied popularly in lighting ,an improved thermal resistance measurement method for LED device/module with forward voltage larger than 15V is achieved by applying external voltage source to the T3Ster/Teraled .The result shows that the external voltage source method can effectively expand the testing range of thermal resistance tester .

  12. Current and voltage measurements at the contact line of the tramway in Brussels; Strom- und Spannungsmessungen an der Oberleitung der Strassenbahn Bruessel

    Energy Technology Data Exchange (ETDEWEB)

    Deutzer, M. [Deutzer Technische Kohle GmbH, Zeuthen (Germany); Winkin, W. [Gerken S.A., Petit-Rechain (Belgium)

    2007-07-01

    The contact line of the tramway in Brussels, Belgium, was designed to be negotiated with gliding shoes. After conversion to the operation with pantographs equipped with collector strips voltage break downs were often observed. Measurements of currents and voltages at the pantographs revealed that the design of the pantograph pan heads and rapid variations of the contact wire heights caused the unfavourable power transmission. (orig.)

  13. The differing behavior of electrosurgical devices made of various electrode materials operating under plasma conditions

    Science.gov (United States)

    Stalder, K. R.; Ryan, T. P.; Gaspredes, J.; Woloszko, J.

    2015-03-01

    Coblation® is an electrosurgical technology which employs electrically-excited electrodes in the presence of saline solution to produce a localized and ionized plasma that can cut, ablate, and otherwise treat tissues for many different surgical needs. To improve our understanding of how Coblation plasmas develop from devices made from different electrode materials we describe several experiments designed to elucidate material effects. Initial experiments studied simple, noncommercial cylindrical electrode test devices operating in buffered isotonic saline without applied suction. The applied RF voltage, approximately 300 V RMS, was sufficient to form glow discharges around the active electrodes. The devices exhibited significantly different operating characteristics, which we ascribe to the differing oxidation tendencies and other physical properties of the electrode materials. Parameters measured include RMS voltage and current, instantaneous voltage and current, temporally-resolved light emission and optical emission spectra, and electrode mass-loss measurements. We correlate these measured properties with some of the bulk characteristics of the electrode materials such as work functions, standard reduction potentials and sputter yields.

  14. 一种间接测量电压互感器二次回路电压降的方法%A Method for Indirectly Measuring Voltage Transformer Secondary Circuit Voltage Drop

    Institute of Scientific and Technical Information of China (English)

    李固; 李纯坚; 傅子明; 刘芬; 梁旭常; 严杰峰

    2014-01-01

    通过研究电压互感器(voltage transformer,VT)二次回路电压降的主要来源,分析 VT二次回路阻抗的构成和运行特性,发现接触电阻是导致 VT二次回路电压降变化的主要原因。当计量电压二次回路阻抗为确定值时,VT二次负荷和 VT二次回路压降存在着对应的关系,可以通过测量二次负荷值来了解二次回路阻抗值,进而推算 VT二次回路压降值。基于此,推导出了用 VT二次负荷计算出 VT二次回路电压降的公式,并提出了通过分析对比 VT二次回路负荷变化大小及趋势,来对 VT二次回路压降开展技术监督的工作方法。%By means of studying main source of voltage drop of voltage transformer secondary circuit,this paper analyzes constitution and running characteristic of VT secondary circuit and discovers the main reason is contact resistance. When im-pedance of metering voltage secondary circuit was a determined value,there was corresponding relationship between VT sec-ondary load and voltage drop and it was able to learn impedance value of the secondary circuit by measuring secondary load value and calculate voltage drop value of VT secondary circuit. A calculation formula for voltage drop value of VT secondary circuit was deduced by VT secondary load and a working method for developing technical supervision on voltage drop of VT secondary circuit was proposed by analyzing and comparing changes and trends of VT secondary load.

  15. Uncertainty estimation of non-ideal analog switches using programmable Josephson voltage standards for mutual inductance measurement in the joule balance

    Science.gov (United States)

    Wang, Gang; Zhang, Zhonghua; Li, Zhengkun; Xu, Jinxin; You, Qiang

    2016-02-01

    Measurement of the mutual inductance is one of the key techniques in the joule balance to determine the Planck constant h, where a standard-square-wave compensation method was proposed to accurately measure the dc value of the mutual inductance. With this method, analog switches are used to compose an analog-switch signal generator to synthesize the excitation and compensation voltages. However, the accuracy of the compensation voltage is influenced by the non-ideal behaviors of analog-switches. In this paper, the effect from these non-ideal switches is analyzed in detail and evaluated with the equivalent circuits. A programmable Josephson voltage standard (PJVS) is used to generate a reference compensation voltage to measure the time integration of the voltage waveform generated by the analog-switch signal generator. Moreover, the effect is also evaluated experimentally by comparing the difference between the mutual inductance measured with the analog-switch signal generator and the value determined by the PJVS-analog-switch generator alternately in the same mutual inductance measurement system. The result shows that the impact of analog switches is 1.97  ×  10-7 with an uncertainty of 1.83  ×  10-7 (k  =  1) and confirms that the analog switch method can be used regularly instead of the PJVS in the mutual inductance measurement for the joule balance experiment.

  16. Front-end and high-voltage electronics developments for compact, dual ion-electron thermal measurements

    Science.gov (United States)

    Cara, A.; Lavraud, B.; Tap, H.; Ballot, Y.; Aoustin, C.; Chassela, O.; Cadu, A.; Devoto, P.; Fedorov, A.; Rouzaud, J.; Rubiella, J.; Sauvaud, J. A.; Seran, H. C.; Bernal, O.; Payan, D.; Rouzies, C.

    2015-12-01

    The Active Monitor Box of Electrostatic Risks (AMBER) is a double-head thermal electron and ion electrostatic analyzer (~0 - 30 keV) that will be launched onboard the Jason-3 spacecraft in 2015. The new generation AMBRE instrument (AMBER_NG) constitutes a significant new evolution that will be based on a single head with newly developed sub-systems to reduce all instrument resources. We will describe the main front-end and high-voltage electronics developments which are being made to perform such dual ion-electron measurements. The first purpose of AMBER_NG is the monitoring of spacecraft charging and of the plasma populations at the origin of this charging. The design is also appropriate for the study of space plasma processes in the Earth's magnetosphere, as well as at other planets where time resolution may not prevail over mass constraints.

  17. Image processing for non-ratiometric measurement of membrane voltage using fluorescent reporters and pulsed laser illumination.

    Science.gov (United States)

    Silve, Aude; Rocke, Sarah; Frey, Wolfgang

    2015-06-01

    The measurement of transmembrane voltages induced by pulsed electric field exposure can be achieved by using fluorescent dyes like ANNINE-6. Such approach requires a quantitative determination of the fluorescence intensity along the cell's membrane by image processing. When high temporal resolution is required, the illumination source is frequently a dye-laser which causes high fluctuations in the intensity of illumination which in turn affects the fluorescence intensity and thus the quality of the results. We propose an image processing technique that allows to overcome the fluctuations and to produce quantitative data. It uses the optical background noise as a correcting factor. Standard deviation in the fluctuations is thus efficiently reduced by at least a factor of 2.5. Additionally we draw attention to the fact that the parasitic component of the laser radiation (ASE) can also suppress fluctuations although it deteriorates wavelength precision.

  18. Fiber optics for voltage and current measurement; Utilizacion de fibras opticas en la medicion de voltaje y corriente

    Energy Technology Data Exchange (ETDEWEB)

    Mendieta Jimenez, Francisco Javier; Santos Dominguez, Martin; Gutierrez Martinez, Celso [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1988-12-31

    This paper offers a brief revision of the techniques employed in the voltage and current measurement in power plants and mention is made also of its main limitations. Likewise the optical methods of transduction of the mentioned electrical variables indicating their advantages and difficulties for its implementation. Finally the activities developed at the Instituto de Investigaciones Elctricas (IIE) in this field are described. [Espanol] En este trabajo se ofrece una breve revision de las tecnicas utilizadas en la medicion de voltaje y corriente en plantas electricas y se mencionan sus principales limitaciones. Asimismo, se presentan los metodos opticos de transduccion de las variables electricas mencionadas, indicando sus ventajas y las dificultades para su realizacion. Finalmente, se describen las actividades que se desarrollan en el Instituto de Investigaciones Electricas (IIE) en este campo.

  19. Electronic measurement of the Boltzmann constant with a quantum-voltage-calibrated Johnson-noise thermometer

    NARCIS (Netherlands)

    Benz, Samuel; White, D. Rod; Qu, JiFeng; Rogalla, Horst; Tew, Weston

    2010-01-01

    Currently, the CODATA value of the Boltzmann constant is dominated by a single gas-based thermometry measurement with a relative standard uncertainty of 1.8×10−6 [P.J. Mohr, B.N. Taylor, D.B. Newell, CODATA recommended values of the fundamental physical constants: 2006, Rev. Mod. Phys. 80 (2008)

  20. Carbon nanotube multi-electrode array chips for noninvasive real-time measurement of dopamine, action potentials, and postsynaptic potentials.

    Science.gov (United States)

    Suzuki, Ikuro; Fukuda, Mao; Shirakawa, Keiichi; Jiko, Hideyasu; Gotoh, Masao

    2013-11-15

    Multi-electrode arrays (MEAs) can be used for noninvasive, real-time, and long-term recording of electrophysiological activity and changes in the extracellular chemical microenvironment. Neural network organization, neuronal excitability, synaptic and phenotypic plasticity, and drug responses may be monitored by MEAs, but it is still difficult to measure presynaptic activity, such as neurotransmitter release, from the presynaptic bouton. In this study, we describe the development of planar carbon nanotube (CNT)-MEA chips that can measure both the release of the neurotransmitter dopamine as well as electrophysiological responses such as field postsynaptic potentials (fPSPs) and action potentials (APs). These CNT-MEA chips were fabricated by electroplating the indium-tin oxide (ITO) microelectrode surfaces. The CNT-plated ITO electrode exhibited electrochemical response, having much higher current density compared with the bare ITO electrode. Chronoamperometric measurements using these CNT-MEA chips detected dopamine at nanomolar concentrations. By placing mouse striatal brain slices on the CNT-MEA chip, we successfully measured synaptic dopamine release from spontaneous firings with a high S/N ratio of 62. Furthermore, APs and fPSPs were measured from cultured hippocampal neurons and slices with high temporal resolution and a 100-fold greater S/N ratio. Our CNT-MEA chips made it possible to measure neurotransmitter dopamine (presynaptic activities), postsynaptic potentials, and action potentials, which have a central role in information processing in the neuronal network. CNT-MEA chips could prove useful for in vitro studies of stem cell differentiation, drug screening and toxicity, synaptic plasticity, and pathogenic processes involved in epilepsy, stroke, and neurodegenerative diseases.

  1. High voltage test techniques

    CERN Document Server

    Kind, Dieter

    2001-01-01

    The second edition of High Voltage Test Techniques has been completely revised. The present revision takes into account the latest international developments in High Voltage and Measurement technology, making it an essential reference for engineers in the testing field.High Voltage Technology belongs to the traditional area of Electrical Engineering. However, this is not to say that the area has stood still. New insulating materials, computing methods and voltage levels repeatedly pose new problems or open up methods of solution; electromagnetic compatibility (EMC) or components and systems al

  2. State estimation of medium voltage distribution networks using smart meter measurements

    OpenAIRE

    Al-Wakeel, Ali; Wu, Jianzhong; Jenkins, Nicholas

    2016-01-01

    Distributed generation and low carbon loads are already leading to some restrictions in the operation of distribution networks and higher penetrations of e.g. PV generation, heat pumps and electric vehicles will exacerbate such problems. In order to manage the distribution network effectively in this new situation, increased real-time monitoring and control will become necessary. In the future, distribution network operators will have smart meter measurements available to them to facilitate s...

  3. Elimination of the channel current effect on the characterization of MOSFET threshold voltage using junction capacitance measurements

    Science.gov (United States)

    Tomaszewski, Daniel; Głuszko, Grzegorz; Łukasiak, Lidia; Kucharski, Krzysztof; Malesińska, Jolanta

    2017-02-01

    An alternative method for an extraction of the MOSFET threshold voltage has been proposed. It is based on an analysis of the MOSFET source-bulk junction capacitance behavior as a function of the gate-source voltage. The effect of the channel current on the threshold voltage extraction is fully eliminated. For the threshold voltage and junction capacitance model parameters non-iterative methods have been used. The proposed method has been demonstrated using a series of MOS transistors manufactured using a standard CMOS technology.

  4. Non-contact measurement of the electrical conductivity and coverage density of silver nanowires for transparent electrodes using Terahertz spectroscopy

    Science.gov (United States)

    Park, Sung-Hyeon; Chung, Wan-Ho; Kim, Hak-Sung

    2017-02-01

    In this work, a terahertz time-domain spectroscopy (THz-TDS) imaging technique was used for non-contact measurement of the conductivity and coverage density (D C) of silver nanowires (SNWs) as transparent electrodes. The reflection mode of THz-TDS with an incident angle of 30° was used, and the sheet resistance (R sh) of SNW films was measured using the four-point probe method. The correlations between the THz reflection ratio and R sh were studied by comparing the results of the four-point probe method and the measured THz reflection ratios. Also, the D C of SNWs was evaluated using THz waveforms with a general refractivity formula. This result matched well with a conventional approximation method using a scanning electron microscope image. Furthermore, defects in the SNWs could be easily detected using the THz-TDS imaging technique. The non-contact THz-TDS measurement method that we developed is expected to be a promising technique for non-contact measurement of the R sh and D C for transparent conductive electrodes.

  5. Biofouling resistance of boron-doped diamond neural stimulation electrodes is superior to titanium nitride electrodes in vivo

    Science.gov (United States)

    Meijs, S.; Alcaide, M.; Sørensen, C.; McDonald, M.; Sørensen, S.; Rechendorff, K.; Gerhardt, A.; Nesladek, M.; Rijkhoff, N. J. M.; Pennisi, C. P.

    2016-10-01

    Objective. The goal of this study was to assess the electrochemical properties of boron-doped diamond (BDD) electrodes in relation to conventional titanium nitride (TiN) electrodes through in vitro and in vivo measurements. Approach. Electrochemical impedance spectroscopy, cyclic voltammetry and voltage transient (VT) measurements were performed in vitro after immersion in a 5% albumin solution and in vivo after subcutaneous implantation in rats for 6 weeks. Main results. In contrast to the TiN electrodes, the capacitance of the BDD electrodes was not significantly reduced in albumin solution. Furthermore, BDD electrodes displayed a decrease in the VTs and an increase in the pulsing capacitances immediately upon implantation, which remained stable throughout the whole implantation period, whereas the opposite was the case for the TiN electrodes. Significance. These results reveal that BDD electrodes possess a superior biofouling resistance, which provides significantly stable electrochemical properties both in protein solution as well as in vivo compared to TiN electrodes.

  6. 负偏压法测试大电压LED器件热阻%Measuring thermal resistance for high voltage LED device and module by applying negative bias voltage

    Institute of Scientific and Technical Information of China (English)

    陈国龙; 雷瑞瑞; 陈焕庭; 陈莹亮; 吕毅军; 高玉琳; 朱丽虹; 陈忠

    2012-01-01

    热阻是衡量LED器件散热性能的重要热学参数.采用外接负偏压恒压源方法,分别使用T3Ster/Teraled热光参数测试仪和NC2991热阻仪对正向电压超过仪器量程的同一型号功率型LED的热阻进行测试,并对两种测试结果的误差进行比较分析讨论.该方法拓展了热阻仪测量范围,使正向电压大于5V的LED器件/模块的热阻测试成为可能.%Thermal resistance is a key parameter on rating the heat dissipating capability of LEDs, so its measurement becomes particularly essential. A thermal resistance measurement method for high voltage LED device and module is provided here, which can measure LED sample with forward voltage larger than 5V by applying negative bias voltage to the T3Ster/Teraled and the NC2991 thermal resistance testers respectively. The results are further compared and discussed and prove to effectively expand the testing range of thermal resistance tester.

  7. Measurement of Fast Voltage Transients in High-Performance Nb3Sn Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Lietzke, A. F.; Sabbi., G. L.; Ferracin, P.; Caspi, S.; Zimmerman, S.; Joseph, J.; Doering, D.; Lizarazo, J.

    2008-06-01

    The Superconducting Magnet group at Lawrence Berkeley National Laboratory has been developing Nb{sub 3}Sn high-field accelerator magnet technology for the last fifteen years. In order to support the magnet R&D effort, we are developing a diagnostic system that can help identify the causes of performance limiting quenches by recording small flux-changes within the magnet prior to quench-onset. These analysis techniques were applied to the test results from recent Nb{sub 3}Sn magnets. This paper will examine various types of events and their distinguishing characteristics. The present measurement techniques are discussed along with the design of a new data acquisition system that will substantially improve the quality of the recorded signals.

  8. General Consideration of Measuring System for Operational Test of Thyristor Valves of Ultra High Voltage DC Power Transmission

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hui-gao; XU Fan; ZHANG Chang-chun; HU Zhi-long; LIU Pu; HUANG Xi-dong; WAN Gan; DING Qian

    2011-01-01

    Thyristor valve is one of the key equipments for ultra high voltage direct current (UHVDC)power transmission projects.Before being installed on site,they need to be tested in a laboratory in order to verify their operational performance to satisfy the technical specification of project related.Test facilities for operational tests of thyristor valves are supposed to enable to undertake more severe electrical stresses than those being applied in the thyristor valves under test (test objects).On the other hand,the stresses applied into the test objects are neither higher nor lower than specified by the specification,because inappropriate stresses applied would result in incorrect evaluation of performance on the test objects,more seriously,would cuase the damage of test objects with expensive cost losing.Generally,the process of operational tests is complicated and performed in a complex synthetic test circuit(hereafter as STC),where there are a lot of sensors used for measuring,monitoring and protection on line to ensure that the test circuit functions in good condition.Therefore,the measuring systems embedded play a core role in STC,acting like "eyes".Based on the first project of building up a STC in China,experience of planning measuring systems is summarized so as to be referenced by related engineers.

  9. Evaluation of uncertainty in the inductive measurement of critical current densities of superconducting films using third-harmonic voltages

    Science.gov (United States)

    Yamasaki, H.; Mawatari, Y.; Nakagawa, Y.; Yamada, H.

    2012-10-01

    Several techniques can be used for inductive measurement of the critical current density Jc of large-area superconducting thin films used in microwave devices and fault-current limiters. The most popular of these methods employs the third-harmonic voltages V3. We have proposed a standard method using V3 for determining Jc under a criterion of electric field E. Here, the uncertainty in the standard method is evaluated. Since the measured Jc is directly proportional to the magnetic field at the upper surface of the superconducting film, the most significant systematic effect is the deviation of the coil-to-film distance Z1 from the prescribed value. The principal origins of this deviation of Z1 are (1) inadequate pressing of the coil onto the film and (2) ice layers occasionally forming between the coil and the protective polyimide film. If these effects are eliminated, uncertainty of Jc originates mainly from (a) uncertainty of the experimental coil coefficient k', which is dominated by uncertainty of the transport Jc, and (b) underestimation of the induced electric field E when using a simple Bean model. For a typical DyBa2Cu3O7 film specimen, the relative combined standard uncertainty in the standard method was evaluated as ˜5%. The effect of the film edge on Jc measurements is also described.

  10. An ionization chamber with magnetic levitated electrodes

    CERN Document Server

    Kawaguchi, T

    1999-01-01

    A new type of ionization chamber which has magnetically levitated electrodes has been developed. The electrodes are supplied voltages for the repelling of ions by a battery which is also levitated with the electrodes. The characteristics of this ionization chamber are investigated in this paper.

  11. Accounting for Interference, Scattering, and Electrode Absorption to Make Accurate Internal Quantum Efficiency Measurements in Organic and Other Thin Solar Cells

    KAUST Repository

    Burkhard, George F.

    2010-05-31

    Accurately measuring internal quantum efficiency requires knowledge of absorption in the active layer of a solar cell. The experimentally accessible total absorption includes significant contributions from the electrodes and other nonactive layers. We suggest a straightforward method for calculating the active layer contribution that minimizes error by subtracting optically-modeled electrode absorption from experimentally measured total absorption. (Figure Presented) © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Note: electrode polarization of Galinstan electrodes for liquid impedance spectroscopy.

    Science.gov (United States)

    Mellor, Brett L; Kellis, Nathan A; Mazzeo, Brian A

    2011-04-01

    Electrode polarization is a significant obstacle in the impedance measurements of ionic liquids. An atomically smooth electrode surface could potentially reduce unwanted impedance contributions from electrode polarization. Liquid metal electrodes were formed by adhering Galinstan to acrylic plates in a parallel-plate capacitor arrangement. Electrode polarization was compared to a similar cell with stainless steel electrodes. The impedance of salt and protein solutions (β-lactoglobulin) was measured from 40 Hz to 110 MHz. Because of oxide layer formation, the performance of the Galinstan electrode is significantly different than the theoretical ideal.

  13. Measurement of Dynamic Resistance in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    Through years, the dynamic resistance across the electrodes has been used for weld quality estimation and contact resistance measurement. However, the previous methods of determining the dynamic resistance were mostly based on measuring the voltage and current on the secondary side...... of the transformer in resistance welding machines, implying defects from induction noise and interference with the leads connected to the electrodes for measuring the voltage. In this study, the dynamic resistance is determined by measuring the voltage on the primary side and the current on the secondary side......, as another application, the proposed method is used to measure the faying surface contact resistance....

  14. Measurement of Dynamic Resistance in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    Through years, the dynamic resistance across the electrodes has been used for weld quality estimation and contact resistance measurement. However, the previous methods of determining the dynamic resistance were mostly based on measuring the voltage and current on the secondary side...... of the transformer in resistance welding machines, implying defects from induction noise and interference with the leads connected to the electrodes for measuring the voltage. In this study, the dynamic resistance is determined by measuring the voltage on the primary side and the current on the secondary side......, as another application, the proposed method is used to measure the faying surface contact resistance....

  15. Batteryless Electroencephalography (EEG): Subthreshold Voltage System-on-a-Chip (SoC) Design for Neurophysiological Measurement

    Science.gov (United States)

    2015-03-01

    ARL-TR-7234 ● MAR 2015 US Army Research Laboratory Batteryless Electroencephalography ( EEG ): Subthreshold Voltage System-on-a...originator. ARL-TR-7234 ● MAR 2015 US Army Research Laboratory Batteryless Electroencephalography ( EEG ): Subthreshold Voltage System-on-a...3. DATES COVERED (From - To) 1 October 2013–30 September 2014 4. TITLE AND SUBTITLE Batteryless Electroencephalography ( EEG ): Subthreshold

  16. Resistor divider for high voltage pulse measurement in vacuum%一种在真空中测量脉冲高电压的电阻分压器

    Institute of Scientific and Technical Information of China (English)

    卫兵; 关永超; 卿燕玲; 陈林; 周良骥; 李晔; 丰树平

    2012-01-01

    A resistor divider has been designed for voltage measurement of diode load for 1 MV/100 kA fast linear transformer driver(LTD). The divider is designed with two stages. The primary stage is a column of alternating annular metal grading rings and tapered insulators enclosing a resistive solution of sodium thiosulfate. A middle electrode is connected to the secondary voltage dividing stage. There is a 4 kΩ resistor in series with the 50 Ω input impedance of the attenuator or oscilloscope. The e-quivalent circuit of the divider which includes distributed capacitance and inductance has been calculated. It indicates that the high frequency limit of the divider is about 200 MHz. The divider has been calibrated in-situ using a P6015A probe and a high voltage pulser. The calibration ratio is 5 400 : 1. The voltage of diode load reaches 1. 08 MV when the charging voltage of LTD stage is ±85 kV respectively, according with the simulation of LTD.%为测量快脉冲直线变压器驱动源(LTD)二极管负载的脉冲高电压,设计了在真空环境中使用的电阻分压器.分压器使用绝缘堆结构,采用静电场模拟分析了分压器的电场分布.建立了包含分布参数的等效电路,并进行了频率响应仿真,可得分压器的频响上限为200 MHz.使用标准高压探头对分压器进行在线标定,分压比标定结果为5 400∶1,与设计值相符合.在LTD调试实验中,模块充电85 kV时二极管电压为1.08 MV,与理论估算结果一致.

  17. All-optical detection of magnetization precession in tunnel junctions under applied voltage

    Science.gov (United States)

    Sasaki, Yuta; Suzuki, Kazuya; Sugihara, Atsushi; Kamimaki, Akira; Iihama, Satoshi; Ando, Yasuo; Mizukami, Shigemi

    2017-02-01

    An all-optical time-resolved magneto-optical Kerr effect measurement of a micron-sized tunnel junction with a CoFeB electrode was performed. The femtosecond (fs) laser-induced magnetization precession was clearly observed at various magnetic field angles. The frequency f and relaxation time τ of the magnetization precession varied with the voltage applied via a MgO barrier. The precession dynamics were in accordance with Kittel’s ferromagnetic resonance mode, and the voltage-induced changes in f and τ were well explained by the voltage-induced change in the perpendicular magnetic anisotropy of -36 fJ/Vm.

  18. Developement of new measuring techniques. A measuring system for testing GIS disconnectors in a high voltage laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Carubelli, C.; Cremonesi, F.; Santagostino, G.

    1988-10-01

    Within the framework of the cooperation between CESI (Italy) and the CPRI (Central Power Research Institute), the problem of a fast and accurate measurements systems for gas-insulated substations (GIS) disconnector testing was analyzed. The particular complexity of the transients to be studied has led to the development of a composite system in which the high frequency components are dealt with by analog techniques and medium frequency components are handled with digital techniques. Sophisticate software was developed to combine the measurement results. Further improvements are expected with the development of a fiber-optics link with an extended bandwidth and the adoption of a digital oscilloscope in order to simplify the overall management of the tests.

  19. Ion-selective electrode for transmembrane pH difference measurements.

    Science.gov (United States)

    Katsu, T; Nakagawa, H; Kanamori, T; Kamo, N; Tsuchiya, T

    2001-04-15

    A triethylammonium-sensitive electrode was constructed using sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate as an ion-exchanger and benzyl 2-nitrophenyl ether as a solvent mediator in a poly(vinylchloride) membrane matrix and was used to determine the pH difference across a cell membrane. The method is based on monitoring of the pH gradient-induced uptake of triethylammonium in situ. The triethylammonium electrode exhibited a near-Nernstian response to triethylammonium in the concentration range of 5 x 10(-6)-1 x 10(-2) M with a slope of 58.5 mV per concentration decade in a buffer solution composed of 150 mM NaCl and 10 mM NaH2PO4/Na2HPO4 (pH 7.5). The limit of detection was 1 microM. In experiments using liposomes, the uptake of triethylammonium into liposomes was quantitatively induced according to the pH difference across the liposomal membrane. The transmembrane pH differences in Escherichia coli cells and the light-induced pH differences across the envelope vesicles of Halobacterium halobium were successfully determined by the present method.

  20. A Mini-Electrochemical System with Integrated Micropipet Tip and Pencil Graphite Electrode for Measuring Cytotoxicity.

    Science.gov (United States)

    Wu, Dong-Mei; Guo, Xiao-Ling; Wang, Qian; Li, Jin-Lian; Cui, Ji-Wen; Zhou, Shi; Hao, Su-E

    2017-01-01

    A novel mini-electrochemical system has been developed for evaluating cytotoxicity of anticancer drugs based on trace cell samples. The mini-electrochemical system was integrated by using pencil graphite modified with threonine as working electrode, an Ag/AgCl reference electrode and a micropipet tip as electrochemical cell. The mini-electrochemical system dramatically reduces sample volumes from 500 μL in a traditional electrochemical system to 10 μL, and exhibits excellent electrocatalytic activity toward oxidation of purine from MCF-7 cells due to increased sensitivity provided by threonine. Moreover, the relationship between peak current and the cell concentration in the range from 3.0 × l0(3) to 7.0 × l0(6) cells/mL was studied, and a nonlinear exponential relationship between them was established over a wide concentration range. In evaluating the effect of anticancer drugs on cell viability, the results of drug cytotoxicity test based on cyclophosphamide were in close agreement with classical 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assays. The proposed device is so simple, cheap, and easy to operate that it could be applied to single-use applications. The mini-electrochemical system proved to be a useful tool and can be applied to electrochemical studies of cancer cells as well as other biological samples such as proteins and DNA.

  1. Topographical and electrochemical nanoscale imaging of living cells using voltage-switching mode scanning electrochemical microscopy.

    Science.gov (United States)

    Takahashi, Yasufumi; Shevchuk, Andrew I; Novak, Pavel; Babakinejad, Babak; Macpherson, Julie; Unwin, Patrick R; Shiku, Hitoshi; Gorelik, Julia; Klenerman, David; Korchev, Yuri E; Matsue, Tomokazu

    2012-07-17

    We describe voltage-switching mode scanning electrochemical microscopy (VSM-SECM), in which a single SECM tip electrode was used to acquire high-quality topographical and electrochemical images of living cells simultaneously. This was achieved by switching the applied voltage so as to change the faradaic current from a hindered diffusion feedback signal (for distance control and topographical imaging) to the electrochemical flux measurement of interest. This imaging method is robust, and a single nanoscale SECM electrode, which is simple to produce, is used for both topography and activity measurements. In order to minimize the delay at voltage switching, we used pyrolytic carbon nanoelectrodes with 6.5-100 nm radii that rapidly reached a steady-state current, typically in less than 20 ms for the largest electrodes and faster for smaller electrodes. In addition, these carbon nanoelectrodes are suitable for convoluted cell topography imaging because the RG value (ratio of overall probe diameter to active electrode diameter) is typically in the range of 1.5-3.0. We first evaluated the resolution of constant-current mode topography imaging using carbon nanoelectrodes. Next, we performed VSM-SECM measurements to visualize membrane proteins on A431 cells and to detect neurotransmitters from a PC12 cells. We also combined VSM-SECM with surface confocal microscopy to allow simultaneous fluorescence and topographical imaging. VSM-SECM opens up new opportunities in nanoscale chemical mapping at interfaces, and should find wide application in the physical and biological sciences.

  2. Accurate surface potential determination in Schottky diodes by the use of a correlated current and capacitance voltage measurements.Application to n-InP

    Institute of Scientific and Technical Information of China (English)

    Ali Ahaitouf; Abdelaziz Ahaitouf; Jean Paul Salvestrini; Hussein Srour

    2011-01-01

    Based on current voltage (I-Vg) and capacitance voltage (C-Vg) measurements,a reliable procedure is proposed to determine the effective surface potential Vd (Vg) in Schottky diodes.In the framework of thermionic emission,our analysis includes both the effect of the series resistance and the ideality factor,even voltage dependent.This technique is applied to n-type indium phosphide (n-InP) Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C-Vg measurements.The study clearly shows that the depletion width and the flat band barrier height deduced from C-Vg,which are important parameters directly related to the surface potential in the semiconductor,should be estimated within our approach to obtain more reliable information.

  3. Development of a nitrate ion-selective electrode based on an Urushi matrix membrane and its application to the direct measurement of nitrate-nitrogen in upland soils.

    Science.gov (United States)

    Ito, S; Baba, K; Asano, Y; Takesako, H; Wada, H

    1996-11-01

    A solid-state nitrate ion-selective electrode based on an Urushi matrix membrane was developed. Urushi, a natural oriental lacquer, has excellent mechanical strength and binding affinity for metal electrodes. Using the same technique for a dip-coating ion-selective electrode, an electrode was prepared by coating and hardening a sensing membrane on the metal base. The effects of the metal electrode on the electrode potential stability, the liquid-membrane components and the oven temperature for hardening of membrane were studied. The sensing membrane, consisting of 27.5 wt.% of o-nitrophenyl octyl ether. 27.5 wt.% of tri-n-octylmethylammonium nitrate and 45 wt.% of raw Urushi latex, was coated with a thickness of 0.5 mm on a silver disc which was plated with Ag/AgCl, then plated with copper and hardened in the oven at 80 degrees C for 50 h. A semi-logarithmic calibration curve of potential versus nitrate ion concentration was obtained over the range 6-60 000 mg l(-1) NO(3)(poststaggered-). The slope of the linear part of the curve was -56 mV per decade change in NO(3)(poststaggered-) concentration. Compared with a PVC matrix nitrate ion-selective electrode, the Urushi matrix nitrate ion-selective electrode was superior in terms of hardness and mechanical strength of the membrane, short response time and long life. The combination of an Urushi matrix nitrate ion-selective electrode with a porous PTFE junction reference electrode, air-tight structured KCl solution chamber and a temperature sensor was applied to field measurements of nitrate-nitrogen concentrations in upland soils. The values obtained for upland soils containing 30-50% of water were good agreement with those for soil solution.

  4. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line.

    Science.gov (United States)

    Zhou, Qiang; He, Wei; Xiao, Dongping; Li, Songnong; Zhou, Kongjun

    2015-12-30

    A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

  5. Study and Experiment on Non-Contact Voltage Sensor Suitable for Three-Phase Transmission Line

    Directory of Open Access Journals (Sweden)

    Qiang Zhou

    2015-12-01

    Full Text Available A voltage transformer, as voltage signal detection equipment, plays an important role in a power system. Presently, more and more electric power systems are adopting potential transformer and capacitance voltage transformers. Transformers are often large in volume and heavyweight, their insulation design is difficult, and an iron core or multi-grade capacitance voltage division structure is generally adopted. As a result, the detection accuracy of transformer is reduced, a huge phase difference exists between detection signal and voltage signal to be measured, and the detection signal cannot accurately and timely reflect the change of conductor voltage signal to be measured. By aiming at the current problems of electric transformation, based on electrostatic induction principle, this paper designed a non-contact voltage sensor and gained detection signal of the sensor through electrostatic coupling for the electric field generated by electric charges of the conductor to be measured. The insulation structure design of the sensor is simple and its volume is small; phase difference of sensor measurement is effectively reduced through optimization design of the electrode; and voltage division ratio and measurement accuracy are increased. The voltage sensor was tested on the experimental platform of simulating three-phase transmission line. According to the result, the designed non-contact voltage sensor can realize accurate and real-time measurement for the conductor voltage. It can be applied to online monitoring for the voltage of three-phase transmission line or three-phase distribution network line, which is in accordance with the development direction of the smart grid.

  6. Measurement of Parasitic Inductances in the Bus-Bar Assembly of a High Power Voltage Source Converter

    Science.gov (United States)

    Datta, Aniket; Narayanan, G.

    2016-12-01

    Insulated gate bipolar transistor (IGBT) based voltage source converters use copper plates with insulating sheets in between them (sandwich bus-bar arrangement) for connecting the different device terminals in the power circuit. In such converters, the parasitic inductances in the power circuit are crucial as they cause overvoltage spikes across the device. Also, the parasitics affect the current sharing between IGBTs when they are connected in parallel in high power converters. The conduction path through plates and fasteners in the bus-bar assembly is three-dimensional and quite complex, making analytical evaluation of the stray inductance quite challenging. The first objective here is to present a simple experimental setup and experimental procedure, which are convenient for power electronic engineers, to measure the bus-bar inductance. The next objective is to carry out experimental studies on the inductances offered by different components and sub-assemblies in a bus-bar assembly. This includes evaluation of inductances of the different conduction paths in typical bus-bar plates. The third objective is to experimentally evaluate the parasitic inductances in the bus-bar assembly of a commercial 250 kVA high power converter. Each leg of this converter consists of two 300 A/1200 V IGBTs connected in parallel. The effective inductance seen by the individual device modules are determined experimentally.

  7. An evaluation method of the profile of plasma-induced defects based on capacitance-voltage measurement

    Science.gov (United States)

    Okada, Yukimasa; Ono, Kouichi; Eriguchi, Koji

    2017-06-01

    Aggressive shrinkage and geometrical transition to three-dimensional structures in metal-oxide-semiconductor field-effect transistors (MOSFETs) lead to potentially serious problems regarding plasma processing such as plasma-induced physical damage (PPD). For the precise control of material processing and future device designs, it is extremely important to clarify the depth and energy profiles of PPD. Conventional methods to estimate the PPD profile (e.g., wet etching) are time-consuming. In this study, we propose an advanced method using a simple capacitance-voltage (C-V) measurement. The method first assumes the depth and energy profiles of defects in Si substrates, and then optimizes the C-V curves. We applied this methodology to evaluate the defect generation in (100), (111), and (110) Si substrates. No orientation dependence was found regarding the surface-oxide layers, whereas a large number of defects was assigned in the case of (110). The damaged layer thickness and areal density were estimated. This method provides the highly sensitive PPD prediction indispensable for designing future low-damage plasma processes.

  8. 直流数字电压表的不确定度评定%Uncertainty of Voltage Measurement Results of Digital Multimeter

    Institute of Scientific and Technical Information of China (English)

    李宏伟

    2012-01-01

    DC voltage measure is the base of DC electric quantity measure. The uncertainty of voltage measurement results of digital multimeter is introduced in this paper, and it analyzes the elements affecting the uncertainty of measurement, calculates the every kind of uncertainty components and finally gives the combined standard uncertainty. Thus it can improve the measuring efficiency and accuracy.%详细叙述了直流数字电压表测量结果的不确定度评估,分析了影响测量不确定度的原因,计算了各不确定度分量并给出合成标准不确定度。通过对测量结果不确定度分析,提高了测量准确度和工作效率。

  9. Development of PDMS-based flexible dry type SEMG electrodes by micromachining technologies

    Science.gov (United States)

    Jung, Jung Mo; Cha, Doo Yeol; Kim, Deok Su; Yang, Hee Jun; Choi, Kyo Sang; Choi, Jong Myoung; Chang, Sung Pil

    2014-09-01

    The authors developed PDMS (polydimethylsiloxane)-based dry type surface electromyography (SEMG) electrodes for myoelectric prosthetic hands. The SEMG electrodes were strongly recommended to be fabricated on a flexible substrate to be compatible with the surface of skin. In this study, the authors designed a bar-shaped dry-type flexible SEMG electrodes comprised of two input electrodes and a reference electrode on a flexible PDMS substrate to measure EMG signals. The space distance between each electrode with a size of 10 mm × 2 mm was chosen to 18 mm to get optimal result according to the simulation result with taking into consideration the conduction velocity and the median frequency of EMG signals. Raw EMG signals were measured from Brachioradialis, Biceps brachii, deltoideus, and pectoralis major muscles, to drive the application of the myoelectric hand prosthesis. Measured raw EMG signals were transformed to root mean square (RMS) EMG signals using Acqknowledge4.2. The experimental peak voltage values of RMS EMG signals from Brachioradialis, Biceps brachii, deltoideus, and pectoralis major muscles were 2.96 V, 4.45 V, 1.74 V, and 2.62 V, respectively. Values from the dry type flexible SEMG electrodes showed higher peak values than a commercially available wet type Ag-AgCl electrode. The study shows that the PDMS-based flexible electrode devised for measuring myoelectric signals from the surface of skin is more useful for prosthetic hands because of its greater sensitivity and flexibility.

  10. Time-resolved photoluminescence measurements for determining voltage-dependent charge-separation efficiencies of subcells in triple-junction solar cells

    Science.gov (United States)

    Tex, David M.; Ihara, Toshiyuki; Akiyama, Hidefumi; Imaizumi, Mitsuru; Kanemitsu, Yoshihiko

    2015-01-01

    Conventional external quantum-efficiency measurement of solar cells provides charge-collection efficiency for approximate short-circuit conditions. Because this differs from actual operating voltages, the optimization of high-quality tandem solar cells is especially complicated. Here, we propose a contactless method, which allows for the determination of the voltage dependence of charge-collection efficiency for each subcell independently. By investigating the power dependence of photoluminescence decays, charge-separation and recombination-loss time constants are obtained. The upper limit of the charge-collection efficiencies at the operating points is then obtained by applying the uniform field model. This technique may complement electrical characterization of the voltage dependence of charge collection, since subcells are directly accessible.

  11. 电解单元槽电压测量偏差的解决方案%Solutions to measurement deviation of voltage of electrolysis unit cell

    Institute of Scientific and Technical Information of China (English)

    路恩勇

    2015-01-01

    通过理论分析和计算,结合实际情况提出了增加引线消除铜排电压和改接线降低铜排电压这两种减小电解槽单元槽电压测量偏差的解决方案,并分析了每种方案的优缺点。%On the basis of theoretical analysis , calculation and practical situations , two solutions to the measurement deviation of voltage of electrolysis unit cells , i.e.adding lead wires to eliminate copper busbar voltage and changing connection wires to reduce copper busbar voltage were proposed .Advantages and disadvantages of the two solutions were analyzed .

  12. Electrochemical thermodynamic measurement system

    Science.gov (United States)

    Reynier, Yvan; Yazami, Rachid; Fultz, Brent T.

    2009-09-29

    The present invention provides systems and methods for accurately characterizing thermodynamic and materials properties of electrodes and electrochemical energy storage and conversion systems. Systems and methods of the present invention are configured for simultaneously collecting a suite of measurements characterizing a plurality of interconnected electrochemical and thermodynamic parameters relating to the electrode reaction state of advancement, voltage and temperature. Enhanced sensitivity provided by the present methods and systems combined with measurement conditions that reflect thermodynamically stabilized electrode conditions allow very accurate measurement of thermodynamic parameters, including state functions such as the Gibbs free energy, enthalpy and entropy of electrode/electrochemical cell reactions, that enable prediction of important performance attributes of electrode materials and electrochemical systems, such as the energy, power density, current rate and the cycle life of an electrochemical cell.

  13. An approach to the diagnosis of metabolic syndrome by the multi-electrode impedance method

    Science.gov (United States)

    Furuya, N.; Sakamoto, K.; Kanai, H.

    2010-04-01

    It is well known that metabolic syndrome can induce myocardial infarction and cerebral infarction. So, it is very important to measure the visceral fat volume. In the electric impedance method, information in the vicinity of the electrodes is strongly reflected. Therefore, we propose a new multi-electrode arrangement method based on the impedance sensitivity theorem to measure the visceral fat volume. This electrode arrangement is designed to enable high impedance sensitivity in the visceral and subcutaneous fat regions. Currents are simultaneously applied to several current electrodes on the body surface, and one voltage electrode pair is arranged on the body surface near the organ of interest to obtain the visceral fat information and another voltage electrode pair is arranged on the body surface near the current electrodes to obtain the subcutaneous fat information. A simulation study indicates that by weighting the impedance sensitivity distribution, as in our method, a high-sensitivity region in the visceral and the subcutaneous fat regions can be formed. In addition, it was confirmed that the visceral fat volume can be estimated by the measured impedance data.

  14. Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

    Directory of Open Access Journals (Sweden)

    Sai Ho Yeung

    2015-09-01

    Full Text Available Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC stimulation, magnetic stimulation (MS and transcutaneous electrical nerve stimulation (TENS are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

  15. Salt-containing wastewater treatment by high-voltage capacitive adsorption of activated carbon fiber electrode insulated by organic film%活性炭纤维覆膜电极高电压电吸附处理含盐废水

    Institute of Scientific and Technical Information of China (English)

    韩丹; 徐有林; 赵贤广; 任朋; 徐炎华

    2015-01-01

    针对电容吸附除盐法中电压低、处理效率低、电极易腐蚀等缺点,对活性炭纤维电极表面进行了覆膜绝缘处理. NaCl模拟溶液实验结果表明,覆膜电极电吸附除盐的最佳操作电压为20 V,最佳作用时间为30 min. 对低浓度NaCl溶液(<300 mg/L),溶液电导率去除率可达80%以上. 吸附等温线拟合结果表明,低电压(<10 V)时,吸附倾向于Langmuir模型;高电压时,吸附更加符合Freundlich模型.%Aiming at the disadvantages of capacitive adsorption desalination process,such as low voltage,low treat-ment efficiency,easily corrosive electrode,etc.,the surface of activated carbon fiber electrode has been treated by membrane-coated insulation. The results from NaCl simulated solution experiment shows that in the membrane-coated electrode electro-adsorption desalination process,the optimal operation voltage is 20 V,and optimal reaction time 30 min. When the low-concentration NaCl solution is less than 300 mg/L,the electrical conductivity removing rate of the solution are above 80%. The result of electro-adsorption isotherm fitting shows that when the low voltage is less than 10 V,the adsorption tends to Langmuir model. When the voltage is high, the adsorption is in accordance with Freundlich model.

  16. Amperometric inhibition biosensors based on horseradish peroxidase and gold sononanoparticles immobilized onto different electrodes for cyanide measurements.

    Science.gov (United States)

    Attar, Aisha; Cubillana-Aguilera, Laura; Naranjo-Rodríguez, Ignacio; de Cisneros, José Luis Hidalgo-Hidalgo; Palacios-Santander, José María; Amine, Aziz

    2015-02-01

    New biosensors based on inhibition for the detection of cyanide and the comparison of the analytical performances of nine enzyme biosensor designs by using three different electrodes: Sonogel-Carbon, glassy carbon and gold electrodes were discussed. Three different horseradish peroxidase immobilization procedures with and without gold sononanoparticles were studied. The amperometric measurements were performed at an applied potential of -0.15V vs. Ag/AgCl in 50mM sodium acetate buffer solution pH=5.0. The apparent kinetic parameters (Kmapp, Vmaxapp) of immobilized HRP were calculated in the absence of inhibitor (cyanide) by using caffeic acid, hydroquinone, and catechol as substrates. The presence of gold sononanoparticles enhanced the electron transfer reaction and improved the analytical performance of the biosensors. The HRP kinetic interactions reveal non-competitive binding of cyanide with an apparent inhibition constant (Ki) of 2.7μM and I50 of 1.3μM. The determination of cyanide can be achieved in a dynamic range of 0.1-58.6μM with a detection limit of 0.03μM which is lower than those reported by previous studies. Hence this biosensing methodology can be used as a new promising approach for detecting cyanide. Copyright © 2014. Published by Elsevier B.V.

  17. 1 μm-thickness ultra-flexible and high electrode-density surface electromyogram measurement sheet with 2 V organic transistors for prosthetic hand control.

    Science.gov (United States)

    Fuketa, Hiroshi; Yoshioka, Kazuaki; Shinozuka, Yasuhiro; Ishida, Koichi; Yokota, Tomoyuki; Matsuhisa, Naoji; Inoue, Yusuke; Sekino, Masaki; Sekitani, Tsuyoshi; Takamiya, Makoto; Someya, Takao; Sakurai, Takayasu

    2014-12-01

    A 64-channel surface electromyogram (EMG) measurement sheet (SEMS) with 2 V organic transistors on a 1 μm-thick ultra-flexible polyethylene naphthalate (PEN) film is developed for prosthetic hand control. The surface EMG electrodes must satisfy the following three requirements; high mechanical flexibility, high electrode density and high signal integrity. To achieve high electrode density and high signal integrity, a distributed and shared amplifier (DSA) architecture is proposed, which enables an in-situ amplification of the myoelectric signal with a fourfold increase in EMG electrode density. In addition, a post-fabrication select-and-connect (SAC) method is proposed to cope with the large mismatch of organic transistors. The proposed SAC method reduces the area and the power overhead by 96% and 98.2%, respectively, compared with the use of conventional parallel transistors to reduce the transistor mismatch by a factor of 10.

  18. Treatment of emulsified oils by electrocoagulation: pulsed voltage applications.

    Science.gov (United States)

    Genc, Ayten; Bakirci, Busra

    2015-01-01

    The effect of pulsed voltage application on energy consumption during electrocoagulation was investigated. Three voltage profiles having the same arithmetic average with respect to time were applied to the electrodes. The specific energy consumption for these profiles were evaluated and analyzed together with oil removal efficiencies. The effects of applied voltages, electrode materials, electrode configurations, and pH on oil removal efficiency were determined. Electrocoagulation experiments were performed by using synthetic and real wastewater samples. The pulsed voltages saved energy during the electrocoagulation process. In continuous operation, energy saving was as high as 48%. Aluminum electrodes used for the treatment of emulsified oils resulted in higher oil removal efficiencies in comparison with stainless steel and iron electrodes. When the electrodes gap was less than 1 cm, higher oil removal efficiencies were obtained. The highest oil removal efficiencies were 95% and 35% for the batch and continuous operating modes, respectively.

  19. Highly Sensitive Measurement of Bio-Electric Potentials by Boron-Doped Diamond (BDD) Electrodes for Plant Monitoring.

    Science.gov (United States)

    Ochiai, Tsuyoshi; Tago, Shoko; Hayashi, Mio; Fujishima, Akira

    2015-10-23

    We describe a sensitive plant monitoring system by the detection of the bioelectric potentials in plants with boron-doped diamond (BDD) electrodes. For sensor electrodes, we used commercially available BDD, Ag, and Pt plate electrodes. We tested this approach on a hybrid species in the genus Opuntia (potted) and three different trees (ground-planted) at different places in Japan. For the Opuntia, we artificially induced bioelectric potential changes by the surface potential using the fingers. We detected substantial changes in bioelectric potentials through all electrodes during finger touches on the surface of potted Opuntia hybrid plants, although the BDD electrodes were several times more sensitive to bioelectric potential change compared to the other electrodes. Similarly for ground-planted trees, we found that both BDD and Pt electrodes detected bioelectric potential change induced by changing environmental factors (temperature and humidity) for months without replacing/removing/changing electrodes, BDD electrodes were 5-10 times more sensitive in this detection than Pt electrodes. Given these results, we conclude that BDD electrodes on live plant tissue were able to consistently detect bioelectrical potential changes in plants.

  20. Active voltage contrast imaging of cross-sectional surface of multilayer ceramic capacitor using helium ion microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, C., E-mail: SAKAI.Chikako@nims.go.jp; Ishida, N.; Masuda, H.; Nagano, S.; Kitahara, M.; Fujita, D. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Ogata, Y. [TAIYO YUDEN CO., LTD., Takasaki-shi, Gunma 370-3347 (Japan)

    2016-08-01

    We studied active voltage contrast (AVC) imaging using helium ion microscopy (HIM). We observed secondary electron (SE) images of the cross-sectional surface of multilayer ceramic capacitors (MLCCs) with and without a voltage applied to the internal electrodes. When no voltage was applied, we obtained an image reflecting the material contrast between the Ni internal electrode region and the BaTiO{sub 3} dielectric region of the cross-sectional surface of the MLCC. When a voltage was applied, the electrical potential difference between the grounded and the positively biased internal electrodes affected the contrast (voltage contrast). Moreover, attenuation of the SE intensity from the grounded to the positively biased internal electrodes was observed in the dielectric region. Kelvin probe force microscopy (KPFM) measurements of the contact potential difference (CPD) were performed on the same sample. By using the AVC image from the HIM observation and the CPD image from the KPFM measurement, we could quantitatively evaluate the electrical potential. We think that the results of this study will lead to an expansion in the number of applications of HIM.

  1. Sensitivities of Key Parameters in the Preparation of Silver/Silver Chloride Electrodes Used in Harned Cell Measurements of pH

    Directory of Open Access Journals (Sweden)

    Richard J. C. Brown

    2011-08-01

    Full Text Available A questionnaire was completed by fourteen world leading national metrology institutes to study the influence of several variables in the preparation of Ag/AgCl electrodes on the accuracy of Harned cell measurements of pH. The performance of each institute in the last decade has been assessed based on their results in eight key comparisons, organized by the Bureau International des Poids et Measures Consultative Committee for Amount of Substance, involving the measurement of pH of phosphate, phthalate, carbonate, borate and tetroxalate buffer solutions. The performance of each laboratory has been correlated to the results of the questionnaire to determine the critical parameters in the preparation of Ag/AgCl electrodes and their sensitivities with respect to the accuracy of pH measurement. This study reveals that the parameters most closely correlated to performance in comparisons are area of electrode wire exposed to the electrolyte, diameter and porosity of the Ag sphere prior to anodisation, amount of Ag converted to AgCl during anodisation, stability times employed for electrodes to reach equilibrium in solution prior to measurement, electrode rejection criteria employed and purity of reagents.

  2. Built-in voltage of organic bulk heterojuction p-i-n solar cells measured by electroabsorption spectroscopy

    Directory of Open Access Journals (Sweden)

    E. Siebert-Henze

    2014-04-01

    Full Text Available We investigate the influence of the built-in voltage on the performance of organic bulk heterojuction solar cells that are based on a p-i-n structure. Electrical doping in the hole and the electron transport layer allows to tune their work function and hence to adjust the built-in voltage: Changing the doping concentration from 0.5 to 32 wt% induces a shift of the work function towards the transport levels and increases the built-in voltage. To determine the built-in voltage, we use electroabsorption spectroscopy which is based on an evaluation of the spectra caused by a change in absorption due to an electric field (Stark effect. For a model system with a bulk heterojunction of BF-DPB and C60, we show that higher doping concentrations in both the electron and the hole transport layer increase the built-in voltage, leading to an enhanced short circuit current and solar cell performance.

  3. High voltage switches having one or more floating conductor layers

    Energy Technology Data Exchange (ETDEWEB)

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  4. High voltage engineering fundamentals

    CERN Document Server

    Kuffel, E; Hammond, P

    1984-01-01

    Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over

  5. High-voltage pulsed generator for dynamic fragmentation of rocks.

    Science.gov (United States)

    Kovalchuk, B M; Kharlov, A V; Vizir, V A; Kumpyak, V V; Zorin, V B; Kiselev, V N

    2010-10-01

    A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

  6. Distance measurements reveal a common topology of prokaryotic voltage-gated ion channels in the lipid bilayer.

    Science.gov (United States)

    Richardson, Jessica; Blunck, Rikard; Ge, Pinghua; Selvin, Paul R; Bezanilla, Francisco; Papazian, Diane M; Correa, Ana M

    2006-10-24

    Voltage-dependent ion channels are fundamental to the physiology of excitable cells because they underlie the generation and propagation of the action potential and excitation-contraction coupling. To understand how ion channels work, it is important to determine their structures in different conformations in a membrane environment. The validity of the crystal structure for the prokaryotic K(+) channel, K(V)AP, has been questioned based on discrepancies with biophysical data from functional eukaryotic channels, underlining the need for independent structural data under native conditions. We investigated the structural organization of two prokaryotic voltage-gated channels, NaChBac and K(V)AP, in liposomes by using luminescence resonance energy transfer. We describe here a transmembrane packing representation of the voltage sensor and pore domains of the prokaryotic Na channel, NaChBac. We find that NaChBac and K(V)AP share a common arrangement in which the structures of the Na and K selective pores and voltage-sensor domains are conserved. The packing arrangement of the voltage-sensing region as determined by luminescence resonance energy transfer differs significantly from that of the K(V)AP crystal structure, but resembles that of the eukaryotic K(V)1.2 crystal structure. However, the voltage-sensor domain in prokaryotic channels is closer to the pore domain than in the K(V)1.2 structure. Our results indicate that prokaryotic and eukaryotic channels that share similar functional properties have similar helix arrangements, with differences arising likely from the later introduction of additional structural elements.

  7. Performance enhancement of ITO/oxide/semiconductor MOS-structure silicon solar cells with voltage biasing.

    Science.gov (United States)

    Ho, Wen-Jeng; Huang, Min-Chun; Lee, Yi-Yu; Hou, Zhong-Fu; Liao, Changn-Jyun

    2014-01-01

    In this study, we demonstrate the photovoltaic performance enhancement of a p-n junction silicon solar cell using a transparent-antireflective ITO/oxide film deposited on the spacing of the front-side finger electrodes and with a DC voltage applied on the ITO-electrode. The depletion width of the p-n junction under the ITO-electrode was induced and extended while the absorbed volume and built-in electric field were also increased when the biasing voltage was increased. The photocurrent and conversion efficiency were increased because more photo-carriers are generated in a larger absorbed volume and because the carriers transported and collected more effectively due to higher biasing voltage effects. Compared to a reference solar cell (which was biased at 0 V), a conversion efficiency enhancement of 26.57% (from 12.42% to 15.72%) and short-circuit current density enhancement of 42.43% (from 29.51 to 42.03 mA/cm(2)) were obtained as the proposed MOS-structure solar cell biased at 2.5 V. In addition, the capacitance-volt (C-V) measurement was also used to examine the mechanism of photovoltaic performance enhancement due to the depletion width being enlarged by applying a DC voltage on an ITO-electrode.

  8. Instrumentation for electrochemical performance characterization of neural electrodes

    Science.gov (United States)

    Marsh, Michael P.; Kruchowski, James N.; Hara, Seth A.; McIntosh, Malcom B.; Forsman, Renae M.; Reed, Terry L.; Kimble, Christopher; Lee, Kendall H.; Bennet, Kevin E.; Tomshine, Jonathan R.

    2017-08-01

    In an effort to determine the chronic stability, sensitivity, and thus the potential viability of various neurochemical recording electrode designs and compositions, we have developed a custom device called the Voltammetry Instrument for Neurochemical Applications (VINA). Here, we describe the design of the VINA and initial testing of its functionality for prototype neurochemical sensing electrodes. The VINA consists of multiple electrode fixtures, a flowing electrolyte bath, associated reservoirs, peristaltic pump, voltage waveform generator, data acquisition hardware, and system software written in National Instrument's LabVIEW. The operation of VINA was demonstrated on a set of boron-doped diamond neurochemical recording electrodes, which were subjected to an applied waveform for a period of eighteen days. Each electrode's cyclic voltammograms (CVs) were recorded, and sensitivity calibration to dopamine (DA) was performed. Results showed an initial decline with subsequent stabilization in the CV current measured during the voltammetric sweep, corresponding closely with changes in electrode sensitivity to DA. The VINA has demonstrated itself as a useful tool for the characterization of electrode stability and chronic electrochemical performance.

  9. Impedance of goat eye lens at different DC voltages.

    Science.gov (United States)

    Kohli, K S; Rai, D V; Jindal, V K; Goyal, N

    1998-09-01

    A computer assisted AC impedance system is used to measure the DC voltage-current (V-I) characteristics and AC impedance of a goat eye lens using a two-probe Ag-AgCl electrode system. The measurement of the V-I characteristics shows that when a DC voltage from 0 mV to 30 mV is applied, the resultant current decreases from an initial value of 0.58 microA to 0.006 microA. However, when the voltage is increases beyond 30 mV, the current increases and reaches a value of 0.9 microA at 100 mV. The data on the frequency response (0.01-10 Hz) of the impedance of lens tissue show an inverse relationship with frequency. The effect of various DC voltages, namely 0, 30, 50, 100 and 200 mV, on the impedance of the eye lens is also investigated over a frequency range of 0.01-10 Hz. The measurement results for both V-I characteristics and AC impedance further suggest the presence of a 30 mV voltage compartment in the goat eye lens.

  10. A Method for Measuring the Volume of Transdermally Extracted Interstitial Fluid by a Three-Electrode Skin Resistance Sensor

    Directory of Open Access Journals (Sweden)

    Dachao Li

    2014-04-01

    Full Text Available It is difficult to accurately measure the volume of transdermally extracted interstitial fluid (ISF, which is important for improving blood glucose prediction accuracy. Skin resistance, which is a good indicator of skin permeability, can be used to determine the volume of extracted ISF. However, it is a challenge to realize in vivo longitudinal skin resistance measurements of microareas. In this study, a three-electrode sensor was presented for measuring single-point skin resistance in vivo, and a method for determining the volume of transdermally extracted ISF using this sensor was proposed. Skin resistance was measured under static and dynamic conditions. The correlation between the skin resistance and the permeation rate of transdermally extracted ISF was proven. The volume of transdermally extracted ISF was determined using skin resistance. Factors affecting the volume prediction accuracy of transdermally extracted ISF were discussed. This method is expected to improve the accuracy of blood glucose prediction, and is of great significance for the clinical application of minimally invasive blood glucose measurement.

  11. Smartphone-based portable biosensing system using impedance measurement with printed electrodes for 2,4,6-trinitrotoluene (TNT) detection.

    Science.gov (United States)

    Zhang, Diming; Jiang, Jing; Chen, Junye; Zhang, Qian; Lu, Yanli; Yao, Yao; Li, Shuang; Logan Liu, Gang; Liu, Qingjun

    2015-08-15

    Rapid, sensitive, selective and portable detection of 2,4,6-trinitrotoluene (TNT) is in high demand for public safety and environmental monitoring. In this study, we reported a smartphone-based system using impedance monitoring for TNT detection. The screen-printed electrodes modified with TNT-specific peptides were used as disposable a biosensor to produce impedance responses to TNT. The responses could be monitored by a hand-held device and send out to smartphone through Bluetooth. Then, the smartphone was used to display TNT responses in real time and report concentration finally. In the measurement, the system was demonstrated to detect TNT at concentration as low as 10(-6) M and distinguish TNT versus different chemicals in high specificity. Thus, the smartphone-based biosensing platform provided a convenient and efficient approach to design portable instruments for chemical detections such as TNT recognition. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Building a Low-Cost, Six-Electrode Instrument to Measure Electrical Properties of Self-Assembled Monolayers of Gold Nanoparticles

    Science.gov (United States)

    Gerber, Ralph W.; Oliver-Hoyo, Maria

    2007-01-01

    The development of a new low-cost, six-electrode instrument for measuring the electrical properties of the self-assembled monolayers of gold particles is being described. The system can also be used to measure conductive liquids, except for those that contain aqua region.

  13. Cold starting of fluorescent lamps - part II: experiments on glow times and electrode damaging

    Science.gov (United States)

    Langer, Reinhard; Paul, Irina; Hilscher, Achim; Horn, Siegfried; Tidecks, Reinhard

    2017-01-01

    In the present work we present experiments on cold start and the resulting electrode damaging (reducing lamp life) of AC driven fluorescent lamps. The crucial parameter is the glow time, determined from time resolved measurements of lamp voltage and current. The relation between the energy consumed during glow phase and the glow time is studied. It turns out that there is no common threshold of energy until the glow-to-arc transition takes place, but strong energy input into the lamp yields short glow times. The transient behaviour from the glow to the arc regime is investigated and the stable operation points of the arc discharge are determined, yielding an arc discharge voltage-current characteristics of the lamp type investigated. The electrode damage is investigated as a function of the open source voltage and the ballast resistance. Subsequent cold starts lead to an increase of the glow time due to electrode damaging, i.e., the electrode damage accumulates. Different regeneration procedures and their effectiveness are compared. Regeneration burning turns out to be more effective than heating up the electrode. A criterion for avoiding high electrode damage is obtained, indicating that the average power during glow time should exceed 20 W.

  14. Total cyanide mass measurement with micro-ion selective electrode for determination of specific activity of carbon-11 cyanide.

    Science.gov (United States)

    Shea, Colleen; Alexoff, David L; Kim, Dohyun; Hoque, Ruma; Schueller, Michael J; Fowler, Joanna S; Qu, Wenchao

    2015-08-01

    In this research, we aim to directly measure the specific activity (SA) of the carbon-11 cyanide ([(11)C]CN¯) produced by our in-house built automated [(11)C]HCN production system and to identify the major sources of (12)C-cyanide ((12)CN¯). The [(11)C]CN¯ is produced from [(11)C]CO2, which is generated by the (14)N(p,α)(11)C nuclear reaction using a cyclotron. Direct measurement of cyanide concentrations was accomplished using a relatively inexpensive, and easy to use ion selective electrode (ISE) which offered an appropriate range of sensitivity for detecting mass. Multiple components of the [(11)C]HCN production system were isolated in order to determine their relative contributions to (12)CN¯ mass. It was determined that the system gases were responsible for approximately 30% of the mass, and that the molecular sieve/nickel furnace unit contributed approximately 70% of the mass. Beam on target (33µA for 1 and 10min) did not contribute significantly to the mass. Additionally, we compared the SA of our [(11)C]HCN precursor determined using the ISE to the SA of our current [(11)C]CN¯ derived radiotracers determined by HPLC to assure there was no significant difference between the two methods. These results are the first reported use of an ion selective electrode to determine the SA of no-carrier-added cyanide ion, and clearly show that it is a valuable, inexpensive and readily available tool suitable for this purpose. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Measurement and Modeling of Personal Exposure to the Electric and Magnetic Fields in the Vicinity of High Voltage Power Lines

    Directory of Open Access Journals (Sweden)

    Wafa Tourab

    2016-06-01

    Conclusion: We project to set own national standards for exposure to electromagnetic fields, in order to achieve a regional database that will be at the disposal of partners concerned to ensure safety of people and mainly workers inside high voltage electrical substations.

  16. High Voltage Distribution

    Science.gov (United States)

    Norbeck, Edwin; Miller, Michael; Onel, Yasar

    2010-11-01

    For detector arrays that require 5 to 10 kV at a few microamps each for hundreds of detectors, using hundreds of HV power supplies is unreasonable. Bundles of hundreds of HV cables take up space that should be filled with detectors. A typical HV module can supply 1 ma, enough current for hundreds of detectors. It is better to use a single HV module and distribute the current as needed. We show a circuit that, for each detector, measures the current, cuts off the voltage if the current exceeds a set maximum, and allows the HV to be turned on or off from a control computer. The entire array requires a single HV cable and 2 or 3 control lines. This design provides the same voltage to all of the detectors, the voltage set by the single HV module. Some additional circuitry would allow a computer controlled voltage drop between the HV and each individual detector.

  17. Near-uv photon efficiency in a TiO2 electrode - Application to hydrogen production from solar energy

    Science.gov (United States)

    Desplat, J.-L.

    1976-01-01

    An n-type (001) TiO2 electrode irradiated at 365 nm was tested under anodic polarization. A saturation current independent of pH and proportional to light intensity has been observed. Accurate measurements of the incident power lead to a 60 per cent photon efficiency. A photoelectrochemical cell built with such an electrode, operated under solar irradiation without concentration, produced an electrolysis current of 0.7 mA/sq cm without applied voltage.

  18. Site Selection for Hvdc Ground Electrodes

    Science.gov (United States)

    Freire, P. F.; Pereira, S. Y.

    2014-12-01

    High-Voltage Direct Current (HVDC) transmission systems are composed of a bipole transmission line with a converter substation at each end. Each substation may be equipped with a HVDC ground electrode, which is a wide area (up to 1 km Ø) and deep (from 3 to 100m) electrical grounding. When in normal operation, the ground electrode will dissipate in the soil the unbalance of the bipole (~1.5% of the rated current). When in monopolar operation with ground return, the HVDC electrode will inject in the soil the nominal pole continuous current, of about 2000 to 3000 Amperes, continuously for a period up to a few hours. HVDC ground electrodes site selection is a work based on extensive geophysical and geological surveys, in order to attend the desired design requirements established for the electrodes, considering both its operational conditions (maximum soil temperature, working life, local soil voltage gradients etc.) and the interference effects on the installations located up to 50 km away. This poster presents the geophysical investigations conducted primarily for the electrodes site selection, and subsequently for the development of the crust resistivity model, which will be used for the interference studies. A preliminary site selection is conducted, based on general geographical and geological criteria. Subsequently, the geology of each chosen area is surveyed in detail, by means of electromagnetic/electrical geophysical techniques, such as magnetotelluric (deep), TDEM (near-surface) and electroresistivity (shallow). Other complementary geologic and geotechnical surveys are conducted, such as wells drilling (for geotechnical characterization, measurement of the water table depth and water flow, and electromagnetic profiling), and soil and water sampling (for measurement of thermal parameters and evaluation of electrosmosis risk). The site evaluation is a dynamic process along the surveys, and some sites will be discarded. For the two or three final sites, the

  19. Millimeter thick ionic polymer membrane-based IPMCs with bimetallic Pd-Pt electrodes

    Science.gov (United States)

    Palmre, Viljar; Kim, Sung Jun; Kim, Kwang

    2011-04-01

    Ionic polymer metal composites (IPMC) are a low-voltage driven Electroactive Polymers (EAP) that can be used as actuators or sensors. This paper presents a comparative study of millimeter thick ionic polymer membrane-based IPMCs with high-performance Pd-Pt electrodes and conventional Pt electrodes. IPMCs assembled with different electrodes are characterized in terms of electromechanical, -chemical and mechanolelectrical properties. The SEM and energy dispersive X-ray (EDS) analysis are used to investigate the distribution of deposited electrode metals in the cross-section of Pd-Pt IPMCs. The study shows that IPMCs assembled with millimeter thick ionic polymer membranes and bimetallic Pd-Pt electrodes are superior in mechanoelectrical sensing and, also, show considerably higher blocking forces compared to the conventional type of IPMCs. Blocking forces more than 30 grams are measured under 4V DC. However, the actuation response is slower than conventional IPMCs having approximately 0.2-0.3 mm thickness.

  20. Development of the Composite High Voltage Optical Fiber Temperature Measurement Cable%高压光纤复合测温电缆的研制

    Institute of Scientific and Technical Information of China (English)

    金金元

    2012-01-01

    In order to use optical fiber distributed temperature monitoring system to on-line monitor the temperature of the cable in operation; a composite high voltage fiber optic temperature measuring cable is developed independently. The structure design, the production process of building in of the fibers, and the performance testing of the composite high voltage optical fiber temperature measuring cable are described in detail.%为利用光纤分布式温度监测系统对运行电缆的温度进行实时在线监测,自主开发了高压光纤复合测温电缆。对高压光纤复合测温电缆结构设计、光纤内置等制造过程和性能检测进行了较为详细的阐述。

  1. Electrochemical properties of titanium nitride nerve stimulation electrodes: an in vitro and in vivo study.

    Science.gov (United States)

    Meijs, Suzan; Fjorback, Morten; Jensen, Carina; Sørensen, Søren; Rechendorff, Kristian; Rijkhoff, Nico J M

    2015-01-01

    The in vivo electrochemical behavior of titanium nitride (TiN) nerve stimulation electrodes was compared to their in vitro behavior for a period of 90 days. Ten electrodes were implanted in two Göttingen minipigs. Four of these were used for electrical stimulation and electrochemical measurements. Five electrodes were kept in Ringer's solution at 37.5°C, of which four were used for electrical stimulation and electrochemical measurements. The voltage transients measured in vivo were 13 times greater than in vitro at implantation and they continued to increase with time. The electrochemical properties in vivo and the tissue resistance (Rtissue) followed a similar trend with time. There was no consistent significant difference between the electrochemical properties of the in vivo and in vitro electrodes after the implanted period. The differences between the in vivo and in vitro electrodes during the implanted period show that the evaluation of electrochemical performance of implantable stimulation electrodes cannot be substituted with in vitro measurements. After the implanted period, however, the performance of the in vivo and in vitro electrodes in saline was similar. In addition, the changes observed over time during the post-implantation period regarding the electrochemical properties of the in vivo electrodes and Rtissue were similar, which indicates that these changes are due to the foreign body response to implantation.

  2. Observation of applied voltage response of dye-doped liquid crystal by optical measurement of real and imaginary parts of complex refractive index

    Science.gov (United States)

    Sakamoto, Moritsugu; Bannai, Kenta; Noda, Kohei; Sasaki, Tomoyuki; Ono, Hiroshi

    2017-09-01

    The behavior of liquid crystal (LC) molecules and dye molecules in a dye-doped liquid crystal (DDLC) under a voltage application condition was quantitatively investigated. To observe the reorientation of these molecules, the real and imaginary parts of the complex refractive index were simultaneously and individually measured using an optical interferometer. The obtained results indicate that the alignment of dye molecules doped in DDLC occurs following the electrically responding LC molecules, near the Freedericksz transition region of LC.

  3. Zanamivir immobilized magnetic beads for voltammetric measurement of neuraminidase at gold-modified boron doped diamond electrode

    Energy Technology Data Exchange (ETDEWEB)

    Wahyuni, Wulan Tri, E-mail: wulantriws@gmail.com [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Kampus IPB Darmaga, Bogor 16680 (Indonesia); Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Ivandini, Tribidasari A.; Saepudin, Endang [Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Einaga, Yasuaki [Department of Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522 (Japan); CREST, JST, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan)

    2016-04-19

    Biomolecule modified magnetic beads has been widely used in separation and sensing process. This study used streptavidin modified magnetic beads to immobilize biotin modified zanamivir. Biotin-streptavidin affinity facilitates immobilization of zanamivir on magnetic beads. Then interaction of zanamivir and neuraminidase was adopted as basic for enzyme detection. Detection of neuraminidase was performed at gold modified BDD using cyclic voltammetry technique. The measurement was carried out based on alteration of electrochemical signals of working electrode as neuraminidase response. The result showed that zanamivir was successfully immobilized on magnetic beads. The optimum amount of magnetic beads for zanamivir immobilization was 120 ug. Linear responses of neuraminidase were detected in concentration range of 0-15 mU. Detection limit (LOD) of measurement was 2.32 mU (R2 = 0.959) with precision as % RSD of 1.41%. Measurement of neuraminidase on magnetic beads could be also performed in the presence of mucin matrix. The linearity range was 0-8 mU with LOD of 0.64 mU (R2 = 0.950) and % RSD of 7.25%.

  4. Reference Electrodes in Metal Corrosion

    Directory of Open Access Journals (Sweden)

    S. Szabó

    2010-01-01

    Full Text Available With especial regard to hydrogen electrode, the theoretical fundamentals of electrode potential, the most important reference electrodes and the electrode potential measurement have been discussed. In the case of the hydrogen electrode, it have been emphasised that there is no equilibrium between the hydrogen molecule (H2 and the hydrogen (H+, hydronium (H3O+ ion in the absence of a suitable catalyst. Taking into account the practical aspects as well, the theorectical basis of working of hydrogen, copper-copper sulphate, mercury-mercurous halide, silver-silver halide, metal-metal oxide, metal-metal sulphate and “Thalamid” electrodes, has been discussed.

  5. Measurement of the Magnetic Fields from High-Voltage (230 kV Substations in Tehran and Assessment of Their Effects

    Directory of Open Access Journals (Sweden)

    Mahdieh Sharifi Fard

    2010-06-01

    Full Text Available Introduction: Recent industrial developments in human societies have caused rapid advancements in technologies of production and distribution of electricity, which in turn result in enhancement of power networks and utilization of high voltages. These networks and the high voltages in transfer lines cause the exposure to electric and magnetic fields. In this study, the situation regarding the magnetic fields from high-voltage (230 kV substations in Tehran was investigated. Material and Methods: In this study, 8 high-voltage (230 kV substations were selected (Shous, Shahid Firouzi, Ozgol, Kan, Tehranpars, Azadegan, Ghorkhane and Besat substations. The premises of each substation was divided into some stations and measurements were done in each one. Measurements were done according to the IEEE std 644-1994 Standard in a way that the device, specifically its probe, was kept at a height of 1 meter above the ground surface. Then, we tried to examine the probable effects of exposure to magnetic fields through the Essex questionnaire, with Cronbach coefficient of 94%, completed by the employees of the substations. These questionnaires were completed by substation operators as an exposed group (36 persons and the employees of the office section of the Tehran regional electric company as a witness group (32 persons. Results: The measured density in none of the stations exceeded the standard limits of the International Commission on Non-Ionizing Radiation Protection. With regard to the questionnaire results about mental and neurological, cardiac and respiratory, and gastrointestinal and auditory disorders, we observed significant differences between witness and exposed groups, however, regarding skin allergies, there was no significant difference. Conclusion: Among all control rooms, the highest measured magnetic field was 6.9 mG in the Ozgol Substation Control Room and the lowest was 2 mG in the post of Shahid Firouzi. The control room of Ozgol

  6. Characteristics of Arcs Between Porous Carbon Electrodes

    OpenAIRE

    Carvou, Erwann; Le Garrec, Jean-Luc; Mitchell, Brian

    2013-01-01

    International audience; Arcs between carbon electrodes present some specific differences compared with metallic arcs. The arc voltage is higher, but does not attain a stable value displaying large fluctuations. Indeed, the arcs are produced by the direct sublimation of the electrodes, without passing through a molten phase. The arc production is also facilitated by both circuit breaking and electric field breakdown. In this paper, arcing has been examined under various conditions (voltage, cu...

  7. Magnetohydrodynamic electrode

    Science.gov (United States)

    Boquist, Carl W.; Marchant, David D.

    1978-01-01

    A ceramic-metal composite suitable for use in a high-temperature environment consists of a refractory ceramic matrix containing 10 to 50 volume percent of a continuous high-temperature metal reinforcement. In a specific application of the composite, as an electrode in a magnetohydrodynamic generator, the one surface of the electrode which contacts the MHD fluid may have a layer of varying thickness of nonreinforced refractory ceramic for electrode temperature control. The side walls of the electrode may be coated with a refractory ceramic insulator. Also described is an electrode-insulator system for a MHD channel.

  8. Charge and fluence lifetime measurements of a dc high voltage GaAs photogun at high average current

    Energy Technology Data Exchange (ETDEWEB)

    J. Grames, R. Suleiman, P.A. Adderley, J. Clark, J. Hansknecht, D. Machie, M. Poelker, M.L. Stutzman

    2011-04-01

    GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a) operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b) limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c) using a large drive laser beam to distribute ion damage over a larger area, and (d) by applying a relatively low bias voltage to the anode to repel ions created within the downstream beam line. A combination of these techniques provided the best total charge extracted lifetimes in excess of 1000 C at dc beam currents up to 9.5 mA, using green light illumination of bulk GaAs inside a 100 kV photogun.

  9. Standard test method for measurement of soil resistivity using the two-electrode soil box method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the equipment and a procedure for the measurement of soil resistivity, for samples removed from the ground, for use in the control of corrosion of buried structures. 1.2 Procedures allow for this test method to be used n the field or in the laboratory. 1.3 The test method procedures are for the resistivity measurement of soil samples in the saturated condition and in the as-received condition. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. Soil resistivity values are reported in ohm-centimeter. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.

  10. Electrical limit of silver nanowire electrodes: Direct measurement of the nanowire junction resistance

    KAUST Repository

    Selzer, Franz

    2016-04-19

    We measure basic network parameters of silvernanowire (AgNW) networks commonly used as transparent conductingelectrodes in organic optoelectronic devices. By means of four point probing with nanoprobes, the wire-to-wire junction resistance and the resistance of single nanowires are measured. The resistanceRNW of a single nanowire shows a value of RNW=(4.96±0.18) Ω/μm. The junction resistanceRJ differs for annealed and non-annealed NW networks, exhibiting values of RJ=(25.2±1.9) Ω (annealed) and RJ=(529±239) Ω (non-annealed), respectively. Our simulation achieves a good agreement between the measured network parameters and the sheet resistanceRS of the entire network. Extrapolating RJ to zero, our study show that we are close to the electrical limit of the conductivity of our AgNW system: We obtain a possible RS reduction by only ≈20% (common RS≈10 Ω/sq). Therefore, we expect further performance improvements in AgNW systems mainly by increasing NW length or by utilizing novel network geometries.

  11. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    Science.gov (United States)

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  12. Influence of implantation on the electrochemical properties of smooth and porous TiN coatings for stimulation electrodes

    Science.gov (United States)

    Meijs, S.; Sørensen, C.; Sørensen, S.; Rechendorff, K.; Fjorback, M.; Rijkhoff, N. J. M.

    2016-04-01

    Objective. To determine whether changes in electrochemical properties of porous titanium nitride (TiN) electrodes as a function of time after implantation are different from those of smooth TiN electrodes. Approach. Eight smooth and 8 porous TiN coated electrodes were implanted in 8 rats. Before implantation, voltage transients, cyclic voltammograms and impedance spectra were recorded in phosphate buffered saline (PBS). After implantation, these measurements were done weekly to investigate how smooth and porous electrodes were affected by implantation. Main results. The electrode capacitance of the porous TiN electrodes decreased more than the capacitance of the smooth electrodes due to acute implantation under fast measurement conditions (such as stimulation pulses). This indicates that protein adhesion presents a greater diffusion limitation for counter-ions for the porous than for the smooth electrodes. The changes in electrochemical properties during the implanted period were similar for smooth and porous TiN electrodes, indicating that cell adhesion poses a similar diffusion limitation for smooth and porous electrodes. Significance. This knowledge can be used to optimize the porous structure of the TiN film, so that the effect of protein adhesion on the electrochemical properties is diminished. Alternatively, an additional coating could be applied on the porous TiN that would prevent or minimize protein adhesion.

  13. Using mesoporous carbon electrodes for brackish water desalination.

    Science.gov (United States)

    Zou, Linda; Li, Lixia; Song, Huaihe; Morris, Gayle

    2008-04-01

    Electrosorptive deionisation is an alternative process to remove salt ions from the brackish water. The porous carbon materials are used as electrodes. When charged in low voltage electric fields, they possess a highly charged surface that induces adsorption of salt ions on the surface. This process is reversible, so the adsorbed salt ions can be desorbed and the electrode can be reused. In the study, an ordered mesoporous carbon (OMC) electrode was developed for electrosorptive desalination. The effects of pore arrangement pattern (ordered and random) and pore size distribution (mesopores and micropores) on the desalination performance was investigated by comparing OMC and activated carbon (AC). It were revealed from X-ray diffraction and N(2) sorption measurements that AC has both micropores and mesopores, whereas ordered mesopores are dominant in OMC. Their performance as potential electrodes to remove salt was evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests at a range of electrolyte concentrations and sweep rates. It is deduced that under the same electrochemical condition the specific capacitance values of OMC electrode (i.e. 133 F/g obtained from CV at a sweep rate of 1 mV/s in 0.1M NaCl solution) are larger than those of AC electrode (107 F/g), suggesting that the former has a higher desalting capacity than the latter. Furthermore, the OMC electrode shows a better rate capacity than the AC electrode. In addition, the desalination capacities were quantified by the batch-mode experiment at low voltage of 1.2V in 25 ppm NaCl solution (50 micros/cm conductivity). It was found that the adsorbed ion amounts of OMC and AC electrodes were 11.6 and 4.3 micromol/g, respectively. The excellent electrosorptive desalination performance of OMC electrode might be not only due to the suitable pore size (average of 3.3 nm) for the propagation of the salt ions, but also due to the ordered mesoporous structure that facilitates desorption of the

  14. Solid oxide electrode kinetics in light of in situ surface studies

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg

    2014-01-01

    The combination of in situ and in particular in operando characterization methods such as electrochemical impedance spectroscopy (EIS) on both technical and model electrode are well known ways to gain some practical insight in electrode reaction kinetics. Yet, is has become clear that in spite...... couple of decades, but recent in situ - or even better - in operando surface measurements such as high temperature scanning probe measurements and Raman spectroscopy have proven very valuable in obtaining new data that can support the interpretation of EIS and current – voltage (i-V) measurements...

  15. An online voltage stability index based on measuring information of phasor measurement unit%基于PMU量测信息的电压稳定在线评估指标

    Institute of Scientific and Technical Information of China (English)

    董雷; 张昭; 蒲天骄; 于汀; 韩巍

    2015-01-01

    为实现对电压稳定的实时在线监测,亟需研究具有良好精确度、线性度和计算快速性的电压稳定在线评估指标,为此提出一种新的基于支路电压方程可行解域的静态电压稳定Lu指标。该指标可由PMU的局部量测信息快速计算获得。进而,为了消除冗余量测信息对指标精确度的影响,提出了仅利用PMU电压量测信息的Lu改进指标Lu.pro。最后,通过仿真算例验证了Lu及Lu.pro指标具有很好的准确性和线性度,并进一步验证了Lu.pro指标在三相不对称情况下的适用性和有效性。结果表明,Lu指标以及改进的Lu.pro指标能够反映系统中电压稳定的薄弱节点及区域,适用于电压稳定的在线监测与评估。%To realize online monitoring of system voltage stability, it is in urgent need of proposing a voltage stability index with ideal accuracy, linearity and computation speed. This paper proposes a new voltage stability index ofLu based on the feasible solution domain of branch voltage equation which can be fast calculated using the local measurement information of PMU. Moreover, in order to eliminate the error produced by redundant measurement information, the improved indexLu.pro is proposed which can be calculated merely with the voltage measurement information of PMU. Simulations are made to prove thatLu andLu.pro are ideal voltage stability indexes with good accuracy and linearity. Furthermore, it is also demonstrated by simulations thatLu.procan be used to evaluate the voltage stability of three-phase unbalanced system. Simulation results show that indexes ofLu andLu.pro can indicate the weak nodes and areas of voltage stability which can be used in online monitoring and evaluation of voltage stability.

  16. HVDC Ground Electrodes - a Source of Geophysical Data

    Science.gov (United States)

    Freire, P. F.; Pereira, S. Y.

    2015-12-01

    The HVDC electrode is a component of a High Voltage Direct Current energy transmission system, and is designed to inject into the ground continuous currents up to 3500 A. The typical HVDC ground electrode is a ring of vertical conductors, 1 km wide, buried a few tens of meters.The design of a HVDC electrode is based on extensive geological, geotechnical and geophysical surveys. Geophysical data are usually electrical (VES) and electromagnetic (TEM/MT) acquisitions, for the modeling of the shallow, near-surface and deep layers of the crust. This survey aims, first, the electrode site selection, and then, at the selected site, this data is combined into a single apparent resistivity curve, which is inverted, allowing for the determination of the layered geoelectric crust model. The injection of electrical continuous current in the electrode is then simulated, with the geoelectric crust model, for the determination of the soil surface potential profile (which is usually asymmetric for different directions, due to non-1D geoelectric models).For the commissioning of a HVDC electrode, field measurements are done, such as electrode grounding resistance, soil surface potentials and metal-to-soil potentials at specific structures (buried pipelines, for instance).The geophysical data acquired during the design phase is a set of data completely independent from the electrical data acquired during the electrode commissioning phase, and both are correlated by the geoelectric model. It happens, therefore, that the geoelectric model can be calibrated based on the electrical data, with the correction of static shifts and other adjustments.This paper suggests that the commissioning of HVDC systems should be associated to a research & development program, with a university or foundation. The idea is to enjoy the opportunity of a more complete field survey, with the acquisition of a wide set of data for a better geological characterization of the area where the electrode was built.

  17. A New Conducting Polymer Electrode for Organic Electroluminescence Devices

    Institute of Scientific and Technical Information of China (English)

    QU Shu; PENG Jing-Cui

    2008-01-01

    @@ Conducting polymer polydimethylsiloxane (PDMS) is studied for the high performance electrode of organic electroluminescence devices. A method to prepare the electrode consisting of a SiC thin film and PDMS is investigated. By using ultra thin SiC films with different thicknesses, the organic electroluminescenee devices are obtained in an ultra vacuum system with the model device PDMS/SiC/PPV/Alq3, where PPV is poly para-phenylene vinylene and Alq3 is tris(8-hydroxyquinoline) aluminium. The capacitance-voltage (C-V), capacitance-frequency (C-F), current-voltage (I- V), radiation intensity-voltage (R- V) and luminance efficiency-voltage (E-V) measurements are systematically studied to investigate the conductivity, Fermi align-ment and devices properties in organic semiconductors. Scanning Kelvin probe measurement shows that the work function of PDMS/SiC anode with a 2.5-nm SiC over layer can be increased by as much as 0.28eV, compared to the conventional ITO anode. The result is attributed to the charge transfer effect and ohmic contacts at the interface.

  18. Optical second harmonic generation measurements for investigating electron injection into a pentacene field effect transistor with Au source and drain electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Eunju; Manaka, Takaaki; Tamura, Ryosuke [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Iwamoto, Mitsumasa [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)], E-mail: iwamoto@pe.titech.ac.jp

    2008-03-03

    The pentacene field effect transistors (FETs)' operation for the injection carrier was revealed by means of the drain current-elapsed time (I{sub ds}-t) and optical second harmonic generation (SHG) measurements. The charge carriers forming the conducting channel of pentacene FETs were mainly holes injected from the Au source electrode. Carrier injection from source and drain electrodes was followed by the carrier trapping, and the SHG signal modulated by the change in the electric field distribution between Au the source and drain electrodes was shown. In particular, at the off state of the FET, electron injection and succeeding trapping were suggested. Furthermore, hole injection assisted by trapped electrons was also suggested.

  19. Development of a trans-admittance mammography (TAM) using 60×60 electrode array

    Science.gov (United States)

    Zhao, Mingkang; Liu, Qin; In Oh, Tong; Woo, Eung Je; Seo, Jin Keun

    2010-04-01

    We have developed a trans-admittance mammography (TAM) system as a supplementary or alternative method of the X-ray mammography to diagnose the breast cancer. Mechanical structure of the system is similar to the X-ray mammography with the breast placed between two plates. The pair of plates is movable to accommodate breasts with different sizes and rotatable to provide multiple images with different projection angles. Without using ionizing radiation, it acquires a projection image of tissue admittivity values. One plate is a flat solid electrode where we apply a constant sinusoidal voltage with a variable frequency. The other is equipped with 60×60 array of current-sensing electrodes, of which potentials are kept at the signal reference level. The electrode array is connected to six switching modules and each module routes current signals from 600 electrodes to two ammeter modules. Each ammeter module includes six channels of ammeters and each one of them comprises an independent current-to-voltage converter, voltage amplifier, ADC and digital phase-sensitive demodulator. Each ammeter sequentially measures exit currents from 50 electrodes chosen by the corresponding switching module. An FPGA controls six ammeters to collect real- and imaginary-parts of trans-admittance data from 300 electrodes. A separate FPGA arbitrates data and command exchanges between a DSP-based main controller and ammeter modules. It also generates a sinusoidal voltage signal to be applied to the breast. All the 3600 complex current data from 12 ammeter modules are transferred to the main controller, which is interfaced to a PC through an isolated USB. The system is provided with a program to display real- and imaginary-parts of measured trans-admittance maps. The measured maps at multiple frequencies are incorporated into a frequency-difference anomaly detection algorithm. In this paper, we describe the design and construction of the system.

  20. Synthesis and characterization of DSSC by using Pt nano-counter electrode: photosensor applications

    Science.gov (United States)

    Yahia, I. S.; AlFaify, S.; Al-ghamdi, Attieh A.; Hafez, Hoda S.; EL-Bashir, S.; Al-Bassam, A.; El-Naggar, A. M.; Yakuphanoglu, F.

    2016-06-01

    Pt electrode prepared by chemical method has been employed as counter electrode in dye-sensitized solar cell. TiO2 nanomaterial was deposited on fluorine-doped tin oxide substrate to be used as photoanode. Structure of the TiO2 and Pt films was investigated by atomic force microscope. The effect of illumination intensity on the photovoltaic parameters such as open circuit voltage, short circuit current density, output power, fill factor and efficiency of these cells was investigated in the range 2.5-130 mW/cm-2. The cell efficiency is stable above 70 mW/cm2. The fill factor is almost constant all over the studied range of illumination intensity. Impedance spectroscopy of the studied device as the summary measurements of the capacitance-voltage, conductance-voltage and series resistance-voltage characteristics were investigated in a wide range of frequencies (5 kHz-1 MHz). At low frequencies, the capacitance has positive values with peak around the origin due to the interfaces. At 200 and 300 kHz, the capacitance is inverted to negative with further increasing of the positive biasing voltage. Above 400 kHz, C-V profile shows complete negative behavior. Also, the impedance-voltage and phase-voltage characteristics were investigated. This cell shows a new promising device for photosensor applications due to high sensitivity in low and high illuminations.

  1. Memristor-integrated voltage-stabilizing supercapacitor system.

    Science.gov (United States)

    Liu, Bin; Liu, Boyang; Wang, Xianfu; Wu, Xinghui; Zhao, Wenning; Xu, Zhimou; Chen, Di; Shen, Guozhen

    2014-08-06

    Voltage-stabilized supercapacitors: A single supercapacitor formed with PCBM/Pt/IPS nanorod-array electrodes is designed and delivers enhanced areal capacitance, capacitance retention, and excellent electrical stability under bending, while a significant voltage-decrease is observed during the discharging process. Once integrated with the memristor, the memristor-integrated supercapacitor systems deliver an extremely low voltage-drop, indicating greatly enhanced voltage-stabilizing features.

  2. Analysis of the Covered Electrode Welding Process Stability on the Basis of Linear Regression Equation

    Directory of Open Access Journals (Sweden)

    Słania J.

    2014-10-01

    Full Text Available The article presents the process of production of coated electrodes and their welding properties. The factors concerning the welding properties and the currently applied method of assessing are given. The methodology of the testing based on the measuring and recording of instantaneous values of welding current and welding arc voltage is discussed. Algorithm for creation of reference data base of the expert system is shown, aiding the assessment of covered electrodes welding properties. The stability of voltage–current characteristics was discussed. Statistical factors of instantaneous values of welding current and welding arc voltage waveforms used for determining of welding process stability are presented. The results of coated electrodes welding properties are compared. The article presents the results of linear regression as well as the impact of the independent variables on the welding process performance. Finally the conclusions drawn from the research are given.

  3. Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

    Science.gov (United States)

    Johnson, Michael J.; Go, David B.

    2015-12-01

    To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ˜30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (corona-like discharges on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.

  4. Measurement of dynamic resistance in resistance spot welding

    Institute of Scientific and Technical Information of China (English)

    Wu Pei; Lü Jiaheng; Wenqi Zhang; Niels Bay

    2007-01-01

    The conventional methods of determining the dynamic resistance were mostly done by measuring the voltage and current at secondary side of transformer in resistance welding machines, in which the measuring set-up normally interferes with the movement of electrode, and the measuring precision is influenced by inductive noise caused by the high welding current. In this study, the dynamic resistance is determined by measuring the voltage at primary side and current at secondary side. This increases the accuracy of measurement because of higher signal-noise ratio, and allows to apply to in-process system without any wires connected to electrodes.

  5. Aspirated capacitor measurements of air conductivity and ion mobility spectra

    CERN Document Server

    Aplin, K L

    2005-01-01

    Measurements of ions in atmospheric air are used to investigate atmospheric electricity and particulate pollution. Commonly studied ion parameters are (1) air conductivity, related to the total ion number concentration, and (2) the ion mobility spectrum, which varies with atmospheric composition. The physical principles of air ion instrumentation are long-established. A recent development is the computerised aspirated capacitor, which measures ions from (a) the current of charged particles at a sensing electrode, and (b) the rate of charge exchange with an electrode at a known initial potential, relaxing to a lower potential. As the voltage decays, only ions of higher and higher mobility are collected by the central electrode and contribute to the further decay of the voltage. This enables extension of the classical theory to calculate ion mobility spectra by inverting voltage decay time series. In indoor air, ion mobility spectra determined from both the novel voltage decay inversion, and an established volt...

  6. The reaction current distribution in battery electrode materials revealed by XPS-based state-of-charge mapping.

    Science.gov (United States)

    Pearse, Alexander J; Gillette, Eleanor; Lee, Sang Bok; Rubloff, Gary W

    2016-07-28

    Morphologically complex electrochemical systems such as composite or nanostructured lithium ion battery electrodes exhibit spatially inhomogeneous internal current distributions, particularly when driven at high total currents, due to resistances in the electrodes and electrolyte, distributions of diffusion path lengths, and nonlinear current-voltage characteristics. Measuring and controlling these distributions is interesting from both an engineering standpoint, as nonhomogenous currents lead to lower utilization of electrode material, as well as from a fundamental standpoint, as comparisons between theory and experiment are relatively scarce. Here we describe a new approach using a deliberately simple model battery electrode to examine the current distribution in a electrode material limited by poor electronic conductivity. We utilize quantitative spatially resolved X-ray photoelectron spectroscopy to measure the spatial distribution of the state-of-charge of a V2O5 model electrode as a proxy measure for the current distribution on electrodes discharged at varying current densities. We show that the current at the electrode-electrolyte interface falls off with distance from the current collector, and that the current distribution is a strong function of total current. We compare the observed distributions with a simple analytical model which reproduces the dependence of the distribution on total current, but fails to predict the correct length scale. A more complete numerical simulation suggests that dynamic changes in the electronic conductivity of the V2O5 concurrent with lithium insertion may contribute to the differences between theory and experiment. Our observations should help inform design criteria for future electrode architectures.

  7. Differential-output B-dot and D-dot monitors for current and voltage measurements on a 20-MA, 3-MV pulsed-power accelerator

    Directory of Open Access Journals (Sweden)

    T. C. Wagoner

    2008-10-01

    signals from a pair are not combined in a balun; they are instead numerically processed for common-mode-noise rejection after digitization. All the current monitors are calibrated on a 76-cm-diameter axisymmetric radial transmission line that is driven by a 10-kA current pulse. The reference current is measured by a current-viewing resistor (CVR. The stack voltage monitors are also differential-output gauges, consisting of one 1.8-cm-diameter D-dot sensor and one null sensor. Hence, each voltage monitor is also a differential detector with two output signals, processed as described above. The voltage monitors are calibrated in situ at 1.5 MV on dedicated accelerator shots with a short-circuit load. Faraday’s law of induction is used to generate the reference voltage: currents are obtained from calibrated outer-MITL B-dot monitors, and inductances from the system geometry. In this way, both current and voltage measurements are traceable to a single CVR. Dependable and consistent measurements are thus obtained with this system of calibrated diagnostics. On accelerator shots that deliver 22 MA to a low-impedance z-pinch load, the peak lineal current densities at the stack, outer-MITL, and inner-MITL monitor locations are 0.5, 1, and 58  MA/m, respectively. On such shots the peak currents measured at these three locations agree to within 1%.

  8. Differential B-dot and D-dot monitors for current and voltage measurements on a 20-MA 3-MV pulsed-power accelerator.

    Energy Technology Data Exchange (ETDEWEB)

    Shoup, Roy Willlam (ITT Industries, Albuquerque, NM); Gilliland, Terrance Leo (Ktech Corporation, Albuquerque, NM); Lee, James R.; Speas, Christopher Shane; Kim, Alexandre A. (High Current Electronic Institute, Russian Academy of Sciences, Tomsk, Russia); Struve, Kenneth William; York, Mathew William; Leifeste, Gordon T.; Rochau, Gregory Alan; Sharpe, Arthur William; Stygar, William A.; Porter, John Larry Jr.; Wagoner, Tim C. (Ktech Corporation, Albuquerque, NM); Reynolds, Paul Gerard (Team Specialty Products Corporation, Albuquerque, NM); Slopek, Jeffrey Scott (Ktech Corporation, Albuquerque, NM); Moore, William B. S.; Dinwoodie, Thomas Albert (Ktech Corporation, Albuquerque, NM); Woodring, R. M. (Ktech Corporation, Albuquerque, NM); Broyles, Robin Scott (Ktech Corporation, Albuquerque, NM); Mills, Jerry Alan; Melville, J. A. (Prodyn Technologies Incorporated, Albuquerque, NM); Dudley, M. E. (Ktech Corporation, Albuquerque, NM); Androlewicz, K. E. (Ktech Corporation, Albuquerque, NM); Mourning, R. W. (Ktech Corporation, Albuquerque, NM); Moore, J. K. (Ktech Corporation, Albuquerque, NM); Serrano, Jason Dimitri (Ktech Corporation, Albuquerque, NM); Ives, H. C. (EG& G, Albuquerque, NM); Johnson, M. F. (Team Specialty Products Corporation, Albuquerque, NM); Peyton, B. P. (Ktech Corporation, Albuquerque, NM); Leeper, Ramon Joe; Savage, Mark Edward; Donovan, Guy Louis; Spielman, R. B. (Ktech Corporation, Albuquerque, NM); Seamen, Johann F.

    2007-12-01

    signals from a pair are not combined in a balun; they are instead numerically processed for common-mode-noise rejection after digitization. All the current monitors are calibrated on a 76-cm-diameter axisymmetric radial transmission line that is driven by a 10-kA current pulse. The reference current is measured by a current-viewing resistor (CVR). The stack voltage monitors are also differential-output gauges, consisting of one 1.8-cm-diameter D-dot sensor and one null sensor. Hence, each voltage monitor is also a differential detector with two output signals, processed as described above. The voltage monitors are calibrated in situ at 1.5 MV on dedicated accelerator shots with a short-circuit load. Faraday's law of induction is used to generate the reference voltage: currents are obtained from calibrated outer-MITL B-dot monitors, and inductances from the system geometry. In this way, both current and voltage measurements are traceable to a single CVR. Dependable and consistent measurements are thus obtained with this system of calibrated diagnostics. On accelerator shots that deliver 22 MA to a low-impedance z-pinch load, the peak lineal current densities at the stack, outer-MITL, and inner-MITL monitor locations are 0.5, 1, and 58 MA/m, respectively. On such shots the peak currents measured at these three locations agree to within 1%.

  9. FIA-automated system used to electrochemically measure nitrite and its interfering chemicals through a 1-2 DAB / Au electrode: gain of sensitivity at upper potentials

    Science.gov (United States)

    Almeida, F. L.; dos Santos Filho, S. G.; Fontes, M. B. A.

    2013-03-01

    The measurement of nitrite and its interfering-chemicals (paracetamol, ascorbic acid and uric acid) was performed employing a Flow-injection Analysis (FIA) system, which was automated using solenoid valves and air-pump. It is very important to quantify nitrite from river water, food and biologic fluids due to its antibacterial capacity in moderated concentrations, or its toxicity for human health even at low concentrations (> 20 μmol L-1 in blood fluids). Electrodes of the electrochemical planar sensor were defined by silk-screen technology. The measuring electrode was made from gold paste covered with 1-2 cis Diaminobenzene (DAB), which allowed good selectivity, linearity, repeatability, stability and optimized gain of sensitivity at 0.5 VAg/AgCl Nafion®117 (6.93 μA mol-1 L mm-2) compared to 0.3 VAg/AgCl Nafion® 117. The reference electrode was obtained from silver/palladium paste modified with chloride and covered with Nafion® 117. The auxiliary electrode was made from platinum paste. It was noteworthy that nitrite response adds to the response of the studied interfering-chemicals and it is predominant for concentrations lower than 175 μmol L-1.

  10. A flexible electrode array for muscle impedance measurements in the mouse hind limb: A tool to speed research in neuromuscular disease

    Science.gov (United States)

    Li, J.; Rutkove, S. B.

    2013-04-01

    Electrical impedance myography (EIM) is a bioelectrical impedance technique focused on the assessment of neuromuscular diseases using tetrapolar surface arrays. Recently, we have shown that reproducible and sensitive EIM measurements can be made on the gastrocnemius muscle of the mouse hind limb and that these are sensitive to disease alterations. A dedicated array would help speed data acquisition and provide additional sensitivity to disease-induced alterations. A flexible electrode array was developed with electrode sizes of 1mm × 1mm by Parlex, Inc. Tetrapolar electrode sets were arranged both parallel to (longitudinal) and orthogonally to (transverse) the major muscle fiber direction of the gastrocnemius muscle. Measurements were made with a dedicated EIM system. A total of 11 healthy animals and 7 animals with spinal muscular atrophy (a form of motor neuron disease) were evaluated after the fur was completely removed with a depilatory agent from the hind limb. Standard electrophysiologic testing (compound motor action potential amplitude and motor unit number estimation) was also performed. The flexible electrode array demonstrated high repeatability in both the longitudinal and transverse directions in the healthy and diseased animals (with intraclass correlation coefficients of 0.94 and 0.89, respectively, for phase angle measured transversely). In addition, differences between healthy and diseased animals were identifiable. For example, the 50 kHz transverse phase angle was higher in the healthy as compared to the SMA animals (16.8° ± 0.5 vs. 14.3° ± 0.7, respectively) at 21 weeks of age (p = 0.01). Differences in anisotropy were also identifiable. Correlations to several standard neurophysiologic parameters also appeared promising. This novel flexible tetrapolar electrode array can be used on the mouse hind limb and provides multidirectional data that can be used to assess muscle health. This technique has the potential of finding widespread use in

  11. 基于同步相量测量的电压稳定指标%Voltage stability index based on synchronized phasor measurement

    Institute of Scientific and Technical Information of China (English)

    随慧斌; 赵建国

    2008-01-01

    A voltage stability index based on synchronized phasor measurements is presented for transmission systems.Power system can be decoupled into several power transmission paths.The ratio of the voltage-drop projection on the start node voltage in a transmission path to the start node voltage is taken as the voltage stability index of power system.which is calculated directly with the loeal vohage phasor information and the weakest transmission path.the complex power flow calculation being thus avoided.Based on a fast and effective PMU(Phasor Measurement Unit)placement.phasor information is provided by direct measurement or indirect calculation of PMUs.The weakest transmission path is determined by the graph theory.By calculating the index value of the weakest transmission path,which approaches to 0.5 when system is prone to voltage collapse,and considering the power system reactive power reserve,the voltage stability can be assessed.Simulation results of IEEE 5-bus and IEEE 30-bus networks show its validity in system collapse prediction.%针对输电网提出了一种基于同步相量测量信息的电压稳定指标.电力系统可以分解成许多电能传输路径.以传输路径首节点电压与末节点电压在首节点电压上的投影之差与首节点电压的比值作为计算电压稳定与否的指标.该指标根据最弱电能传输路径利用局部电压相量测量信息直接计算得出,避免了复杂的潮流计算.局部电压相量测量数据由相量测量单元PMU提供.基于一种快速有效的PMU配置方法.利用直接测量或间接计算的数据作为此稳定指标计算所需要的电压相量信息.运用图论的基本思想寻找电能最弱传输路径.通过计算电能最弱传输路径的电压稳定指标和系统无功储备情况判断系统电压稳定度,当系统接近不稳定状态时,最弱传输路径的电压稳定指标值趋向于临界值0.5.在IEEE 5节点和IEEE 30节点系统上的仿真表明了该指

  12. High-voltage picoamperemeter

    Energy Technology Data Exchange (ETDEWEB)

    Bugl, Andrea; Ball, Markus; Boehmer, Michael; Doerheim, Sverre; Hoenle, Andreas; Konorov, Igor [Technische Universitaet Muenchen, Garching (Germany); Ketzer, Bernhard [Technische Universitaet Muenchen, Garching (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2014-07-01

    Current measurements in the nano- and picoampere region on high voltage are an important tool to understand charge transfer processes in micropattern gas detectors like the Gas Electron Multiplier (GEM). They are currently used to e.g. optimize the field configuration in a multi-GEM stack to be used in the ALICE TPC after the upgrade of the experiment during the 2nd long shutdown of the LHC. Devices which allow measurements down to 1pA at high voltage up to 6 kV have been developed at TU Muenchen. They are based on analog current measurements via the voltage drop over a switchable shunt. A microcontroller collects 128 digital ADC values and calculates their mean and standard deviation. This information is sent with a wireless transmitting unit to a computer and stored in a root file. A nearly unlimited number of devices can be operated simultaneously and read out by a single receiver. The results can also be displayed on a LCD directly at the device. Battery operation and the wireless readout are important to protect the user from any contact to high voltage. The principle of the device is explained, and systematic studies of their properties are shown.

  13. Development and Application of a Wireless Sensor for Space Charge Density Measurement in an Ultra-High-Voltage, Direct-Current Environment.

    Science.gov (United States)

    Xin, Encheng; Ju, Yong; Yuan, Haiwen

    2016-10-20

    A space charge density wireless measurement system based on the idea of distributed measurement is proposed for collecting and monitoring the space charge density in an ultra-high-voltage direct-current (UHVDC) environment. The proposed system architecture is composed of a number of wireless nodes connected with space charge density sensors and a base station. The space charge density sensor based on atmospheric ion counter method is elaborated and developed, and the ARM microprocessor and Zigbee radio frequency module are applied. The wireless network communication quality and the relationship between energy consumption and transmission distance in the complicated electromagnetic environment is tested. Based on the experimental results, the proposed measurement system demonstrates that it can adapt to the complex electromagnetic environment under the UHVDC transmission lines and can accurately measure the space charge density.

  14. Dielectric barrier discharges with steep voltage rise: mapping of atomic nitrogen in single filaments measured by laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Lukas, C.; Spaan, M.; Schulz-von der Gathen, V.; Thomson, M.; Wegst, R.; Döbele, H. F.; Neiger, M.

    2001-08-01

    Space and time resolved relative atomic density distributions of nitrogen have been measured for the first time at a single filament within a dielectric barrier discharge (DBD) reactor with submillimetre radial dimensions. Two-photon-Absorption Laser-Induced Fluorescence (TALIF) spectroscopy of atomic nitrogen using radiation at λ = 206.7 nm is applied to a DBD with fast rising voltage amplitudes. The decay time of the atomic nitrogen density depends strongly on the position within the discharge and the distance from the dielectric where the lifetime is maximum. Admixed oxygen leads to an increase of the N density decay by an order of magnitude even at small fractions.

  15. Accurate Switched-Voltage voltage averaging circuit

    OpenAIRE

    金光, 一幸; 松本, 寛樹

    2006-01-01

    Abstract ###This paper proposes an accurate Switched-Voltage (SV) voltage averaging circuit. It is presented ###to compensated for NMOS missmatch error at MOS differential type voltage averaging circuit. ###The proposed circuit consists of a voltage averaging and a SV sample/hold (S/H) circuit. It can ###operate using nonoverlapping three phase clocks. Performance of this circuit is verified by PSpice ###simulations.

  16. Atmospheric Pressure Glow Discharge with Liquid Electrode

    Science.gov (United States)

    Tochikubo, Fumiyoshi

    2013-09-01

    Nonthermal atmospheric pressure plasmas in contact with liquid are widely studied aiming variety of plasma applications. DC glow discharge with liquid electrode is an easy method to obtain simple and stable plasma-liquid interface. When we focus attention on liquid-phase reaction, the discharge system is considered as electrolysis with plasma electrode. The plasma electrode will supply electrons and positive ions to the liquid surface in a different way from the conventional metal electrode. However, the phenomena at plasma-liquid interface have not been understood well. In this work, we studied physical and chemical effect in liquid induced by dc atmospheric pressure glow discharge with liquid electrode. The experiment was carried out using H-shaped Hoffman electrolysis apparatus filled with electrolyte, to separate the anodic and cathodic reactions. Two nozzle electrodes made of stainless steel are set about 2 mm above the liquid surface. By applying a dc voltage between the nozzle electrodes, dc glow discharges as plasma electrodes are generated in contact with liquid. As electrolyte, we used aqueous solutions of NaCl, Na2SO4, AgNO3 and HAuCl4. AgNO3 and HAuCl4 are to discuss the reduction process of metal ions for synthesis of nanoparticles (NPs). OH radical generation yield in liquid was measured by chemical probe method using terephthalic acid. Discharge-induced liquid flow was visualized by Schlieren method. Electron irradiation to liquid surface (plasma cathode) generated OH- and OH radical in liquid while positive ion irradiation (plasma anode) generated H+ and OH radical. The generation efficiency of OH radical was better with plasma anode. Both Ag NPs in AgNO3 and Au NPs in HAuCl4 were synthesized with plasma cathode while only Au NPs were generated with plasma anode. Possible reaction process is qualitatively discussed. The discharge-induced liquid flow such as convection pattern was strongly influenced by the gas flow on the liquid surface. This work

  17. Measuring sensor and process to determine the state of charge of a battery. Messonde und Verfahren zur Bestimmung des Ladezustandes eine Akkumulators

    Energy Technology Data Exchange (ETDEWEB)

    Bothe, F.W.; Brilie, U.

    1983-10-20

    The state of charge of a lead battery can be determined by measuring its off-load voltage, if the off-load voltage is measured at a mini-cell situated in the electrolyte of the battery, which has two electrodes with the same material as the positive and negative plates of the battery.

  18. Arsenic removal from groundwater using low-cost carbon composite electrodes for capacitive deionization.

    Science.gov (United States)

    Lee, Ju-Young; Chaimongkalayon, Nantanee; Lim, Jinho; Ha, Heung Yong; Moon, Seung-Hyeon

    2016-01-01

    Affordable carbon composite electrodes were developed to treat low-concentrated groundwater using capacitive deionization (CDI). A carbon slurry prepared using activated carbon powder (ACP), poly(vinylidene fluoride), and N-methyl-2-pyrrolidone was employed as a casting solution to soak in a low-cost porous substrate. The surface morphology of the carbon composite electrodes was investigated using a video microscope and scanning electron microscopy. The capacitance and electrical conductivity of the carbon composite electrodes were then examined using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. According to the CV and EIS measurements, the capacitances and electrical conductivities of the carbon composite electrodes were in the range of 8.35-63.41 F g(-1) and 0.298-0.401 S cm(-1), respectively, depending on ACP contents. A CDI cell was assembled with the carbon composite electrodes instead of with electrodes and current collectors. The arsenate removal test included an investigation of the optimization of several important operating parameters, such as applied voltage and solution pH, and it achieved 98.8% removal efficiency using a 1 mg L(-1) arsenate solution at a voltage of 2 V and under a pH 9 condition.

  19. Measurement of an Electric Arc Spectra

    OpenAIRE

    Šimek, D.

    2015-01-01

    Article is focused on electric arc spectroscopy diagnostics related to electric low voltage apparatuses. The first attempts of spectroscopy measurements are dealt with. An example of radiation spectra of the electric arc burning between copper electrodes is presented. The problems connected with the measurements are discussed.

  20. Pulsed voltage electrospray ion source and method for preventing analyte electrolysis

    Science.gov (United States)

    Kertesz, Vilmos; Van Berkel, Gary

    2011-12-27

    An electrospray ion source and method of operation includes the application of pulsed voltage to prevent electrolysis of analytes with a low electrochemical potential. The electrospray ion source can include an emitter, a counter electrode, and a power supply. The emitter can include a liquid conduit, a primary working electrode having a liquid contacting surface, and a spray tip, where the liquid conduit and the working electrode are in liquid communication. The counter electrode can be proximate to, but separated from, the spray tip. The power system can supply voltage to the working electrode in the form of a pulse wave, where the pulse wave oscillates between at least an energized voltage and a relaxation voltage. The relaxation duration of the relaxation voltage can range from 1 millisecond to 35 milliseconds. The pulse duration of the energized voltage can be less than 1 millisecond and the frequency of the pulse wave can range from 30 to 800 Hz.

  1. Compact Electrochemical System Using On-Chip Sensor Electrodes and Integrated Devices

    Science.gov (United States)

    Yamazaki, Tomoyuki; Ikeda, Takaaki; Ishida, Makoto; Sawada, Kazuaki

    2011-04-01

    We report a compact electrochemical sensing system to implement cyclic voltammetry. This type of sensor needs a working electrode, counter electrode, and reference electrode, all of which were integrated on a single chip. The electrochemical system also needs a potentiostat and an input voltage-generating circuit, which were developed using on-chip active devices and a few discrete passive components. This is the first sensor system incorporating electrode-side input voltage generation for electrochemical measurements using an on-chip operational amplifier, which replaces a bulky external voltage controller. A continuous cyclic voltammetry measurement was conducted with a well-studied ferricyanide solution to demonstrate the operation of the intelligent sensor chip. A clear peak was observed and linearity to the target chemical concentration was obtained between the peak height and concentration of the ferricyanide solution. With potential for mass production and small size, this sensor chip could be the best candidate to realize point-of-care testing. This sensor chip is a milestone of a fully integrated electrochemical sensor chip.

  2. Laboratory experiments on current flow between stationary and moving electrodes in magnetoplasmas

    Science.gov (United States)

    Stenzel, Reiner L.; Urrutia, J. M.

    1990-01-01

    Laboratory experiments were performed in order to investigate the basic physics of current flow between tethered electrodes in magnetoplasmas. The major findings are summarized. The experiments are performed in an effectively very large laboratory plasma in which not only the nonlinear current collection is addressed but also the propagation and spread of currents, the formation of current wings by moving electrodes, the current closure, and radiation from transmission lines. The laboratory plasma consists of a pulsed dc discharge whose Maxwellian afterglow provides a quiescent, current-free uniform background plasma. Electrodes consisting of collectors and electron emitters are inserted into the plasma and a pulsed voltage is applied between two floating electrodes via insulated transmission lines. Besides the applied current in the wire, the total current density in the plasma is obtained from space and time resolved magnetic probe measurements via Maxwell's law. Langmuir probes yield the plasma parameters.

  3. Experimental study of noncontact ultrasonic motor with non-symmetrical electrode

    Institute of Scientific and Technical Information of China (English)

    Yang Bin; Liu Jing-Quan; Chen Di; Zhou Wei-Min; Cai Bing-Chu

    2006-01-01

    We have proposed a novel noncontact ultrasonic motor based on non-symmetrical electrode driving. The configuration of this electrode and the fabrication process of rotors are presented. Its vibration characteristics are computed and analysed by using the finite element method and studied experimentally. Good agreement between them is obtained. Moreover, it is also shown that this noncontact ultrasonic motor is operated in antisymmetric radial vibration mode of B21 mode. The maximum revolution speed for three-blade and six-blade rotors are 5100 and 3700r/min at an input voltage of 20V, respectively. Also, the noncontact high-speed revolution of the rotors can be realized by the parts of Ⅰ, Ⅲ of the electrode or Ⅱ, Ⅳ of the electrode. The levitation distance between the stator and rotor is about 140/μm according to the theoretical calculation and the experimental measurement.

  4. Membrane-electrode structures for molecular catalysts for use in fuel cells and other electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, John B.; Zhu, Xiaobing; Hwang, Gi Suk; Martin, Zulima; He, Qinggang; Driscoll, Peter; Weber, Adam; Clark, Kyle

    2016-09-27

    Water soluble catalysts, (M)meso-tetra(N-Methyl-4-Pyridyl)Porphinepentachloride (M=Fe, Co, Mn & Cu), have been incorporated into the polymer binder of oxygen reduction cathodes in membrane electrode assemblies used in PEM fuel cells and found to support encouragingly high current densities. The voltages achieved are low compared to commercial platinum catalysts but entirely consistent with the behavior observed in electroanalytical measurements of the homogeneous catalysts. A model of the dynamics of the electrode action has been developed and validated and this allows the MEA electrodes to be optimized for any chemistry that has been demonstrated in solution. It has been shown that improvements to the performance will come from modifications to the structure of the catalyst combined with optimization of the electrode structure and a well-founded pathway to practical non-platinum group metal catalysts exists.

  5. A portable voltage measuring system of series battery%便携式串联电池组电压检测系统

    Institute of Scientific and Technical Information of China (English)

    郝迎吉; 彭斌; 赵大帅

    2009-01-01

    介绍一种便携式串联电池组电压检测系统,该系统以C8051F410嵌入式单片机作为核心,利用普通光耦设计线性测试电路.实现在线测量电池电压,并在液晶显示器上实时显示监控系统的运行状况.该系统设计采用的器件少.结构肾凑,具有较高的性价比和市场推广价值.%This paper introduces a portable voltage measuring system of series battery. The system uses C8051F410 microprocessor as a core,and makes use of common optocoupler for designing linear circuit. It realizes the on-line voltage measurement of battery and real-time display for the system operating state.This system design has some advantages such as less components,compact configuration,higher cost performance and popular value of market.

  6. Influence of plasma-etch damage on the interface states in SOI structures investigated by capacitance-voltage measurements and simulations

    Science.gov (United States)

    Jo, Yeong-Deuk; Koh, Jung-Hyuk; Ha, Jae-Geun; Kim, Ji-Hong; Cho, Dae-Hyung; Moon, Byung-Moo; Koo, Sang-Mo

    2009-12-01

    Au/SiO2/n-Si metal-oxide-silicon-on-insulator (MOSOI) capacitors were fabricated to study the damage caused by reactive ion etching (RIE) on (1 1 0) oriented silicon-on-insulator (SOI) substrates. The MOSOI capacitors with an etch-damaged SOI layer were characterized by capacitance-voltage (C-V) measurements and compared to the sacrificial oxidation treated samples and the reference samples without etching treatment. The measurements revealed that C-V curves significantly change and a negative voltage shift occurs for plasma-damaged capacitors. The simulated band diagram profiles and potential distribution of the corresponding structures indicate that the C-V shift is mainly due to the removal of a parasitic depletion capacitance (Cp) in the substrate, when the interface charges (Qf) are present at the gate oxide/SOI interface. For etch-damaged MOSOI samples, the surface roughness and the interface charges (Qf) have been found to increase by ~1.94 × 1012 cm-2 with respect to the reference devices, whereas the increase was reduced for sacrificial-oxidation treated samples, which implies a recovery from the plasma-induced etch damage on SOI structures.

  7. A battery-based, low-noise voltage source

    Science.gov (United States)

    Wagner, Anke; Sturm, Sven; Schabinger, Birgit; Blaum, Klaus; Quint, Wolfgang

    2010-06-01

    A highly stable, low-noise voltage source was designed to improve the stability of the electrode bias voltages of a Penning trap. To avoid excess noise and ground loops, the voltage source is completely independent of the public electric network and uses a 12 V car battery to generate output voltages of ±15 and ±5 V. First, the dc supply voltage is converted into ac-voltage and gets amplified. Afterwards, the signal is rectified, filtered, and regulated to the desired output value. Each channel can deliver up to 1.5 A. The current as well as the battery voltage and the output voltages can be read out via a universal serial bus (USB) connection for monitoring purposes. With the presented design, a relative voltage stability of 7×10-7 over 6.5 h and a noise level equal or smaller than 30 nV/√Hz is achieved.

  8. Electrode structure and methods of making same

    Energy Technology Data Exchange (ETDEWEB)

    Ruud, James Anthony; Browall, Kenneth Walter; Rehg, Timothy Joseph; Renou, Stephane; Striker, Todd-Michael

    2010-04-06

    A method of making an electrode structure is provided. The method includes disposing an electrocatalytic material on an electrode, applying heat to the electrocatalytic material to form a volatile oxide of the electrocatalytic material, and applying a voltage to the electrode to reduce the volatile oxide to provide a number of nano-sized electrocatalytic particles on or proximate to a triple phase boundary, where the number of nano-sized electrocatalytic particles is greater on or proximate to the triple phase boundary than in an area that is not on or proximate to the triple phase boundary, and where the triple phase boundary is disposed on the electrode.

  9. Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

    Science.gov (United States)

    Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

    2017-10-04

    We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10(-3) S cm(-1)) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g(-1) at 0.1 A g(-1)), better rate capability (64% capacity retention until 20 A g(-1)), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg(-1) at 1 A g(-1)) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

  10. The measurement of gas-liquid two-phase flows in a small diameter pipe using a dual-sensor multi-electrode conductance probe

    Science.gov (United States)

    Zhai, Lu-Sheng; Bian, Peng; Han, Yun-Feng; Gao, Zhong-Ke; Jin, Ning-De

    2016-04-01

    We design a dual-sensor multi-electrode conductance probe to measure the flow parameters of gas-liquid two-phase flows in a vertical pipe with an inner diameter of 20 mm. The designed conductance probe consists of a phase volume fraction sensor (PVFS) and a cross-correlation velocity sensor (CCVS). Through inserting an insulated flow deflector in the central part of the pipe, the gas-liquid two-phase flows are forced to pass through an annual space. The multiple electrodes of the PVFS and the CCVS are flush-mounted on the inside of the pipe wall and the outside of the flow deflector, respectively. The geometry dimension of the PVFS is optimized based on the distribution characteristics of the sensor sensitivity field. In the flow loop test of vertical upward gas-liquid two-phase flows, the output signals from the dual-sensor multi-electrode conductance probe are collected by a data acquisition device from the National Instruments (NI) Corporation. The information transferring characteristics of local flow structures in the annular space are investigated using the transfer entropy theory. Additionally, the kinematic wave velocity is measured based on the drift velocity model to investigate the propagation behavior of the stable kinematic wave in the annular space. Finally, according to the motion characteristics of the gas-liquid two-phase flows, the drift velocity model based on the flow patterns is constructed to measure the individual phase flow rate with higher accuracy.

  11. Reversible voltage dependent transition of abnormal and normal bipolar resistive switching

    Science.gov (United States)

    Wang, Guangyu; Li, Chen; Chen, Yan; Xia, Yidong; Wu, Di; Xu, Qingyu

    2016-11-01

    Clear understanding the mechanism of resistive switching is the important prerequisite for the realization of high performance nonvolatile resistive random access memory. In this paper, binary metal oxide MoOx layer sandwiched by ITO and Pt electrodes was taken as a model system, reversible transition of abnormal and normal bipolar resistive switching (BRS) in dependence on the maximum voltage was observed. At room temperature, below a critical maximum voltage of 2.6 V, butterfly shaped I-V curves of abnormal BRS has been observed with low resistance state (LRS) to high resistance state (HRS) transition in both polarities and always LRS at zero field. Above 2.6 V, normal BRS was observed, and HRS to LRS transition happened with increasing negative voltage applied. Temperature dependent I-V measurements showed that the critical maximum voltage increased with decreasing temperature, suggesting the thermal activated motion of oxygen vacancies. Abnormal BRS has been explained by the partial compensation of electric field from the induced dipoles opposite to the applied voltage, which has been demonstrated by the clear amplitude-voltage and phase-voltage hysteresis loops observed by piezoelectric force microscopy. The normal BRS was due to the barrier modification at Pt/MoOx interface by the accumulation and depletion of oxygen vacancies.

  12. Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Michael J. [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indianapolis 46556 (United States); Go, David B., E-mail: dgo@nd.edu [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indianapolis 46556 (United States); Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indianapolis 46556 (United States)

    2015-12-28

    To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ∼30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (<30 V) to generate breakdown in air without the need for conventional high-voltage electrical equipment. Piezoelectric transformers (PTs) use their inherent electromechanical resonance to produce a voltage amplification, such that the surface of the piezoelectric exhibits a large surface voltage that can generate corona-like discharges on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.

  13. Ingot niobium as candidate electrode material for Jefferson Lab 200 kV inverted electron photogun

    Energy Technology Data Exchange (ETDEWEB)

    BastaniNejad, Mahzad, E-mail: Mahzad@jlab.org [Christopher Newport University, Newport News VA (United States); Suleiman, Riad, E-mail: suleiman@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

    2015-12-04

    This contribution describes the field emission characterization of niobium electrodes using a DC high voltage field emission test apparatus. A total of six electrodes were evaluated: two large-grain, two single-crystal, and two fine-grain that were chemically polished using a buffered-chemical acid solution. Field emission from niobium electrodes could be significantly reduced and sometimes completely eliminated, by introducing krypton gas into the vacuum chamber while the electrode is biased at high voltage. Of all the electrodes tested, a large-grain niobium electrode performed the best, exhibiting no measurable field emission (<10 pA) at 225 kV with 20 mm cathode/anode gap, corresponding to a field strength of 18.7 MV/m. Motivated by these results, an inverted electron photogun operated at Jefferson Lab injector test facility was equipped with a large-grain niobium cathode electrode and it has been successfully conditioned to 225 kV without field emission. This photogun was used to study strained superlattice GaAs and K{sub 2}CsSb photocathodes at high beam currents.

  14. Voltage-Sensitive Load Controllers for Voltage Regulation and Increased Load Factor in Distribution Systems

    DEFF Research Database (Denmark)

    Douglass, Philip James; Garcia-Valle, Rodrigo; Østergaard, Jacob

    2014-01-01

    consumption which can be mapped to temperature setpoint offsets of thermostat controlled loads. In networks where a lower voltage level corresponds to high system load (and vice versa), this controller acts to regulate voltage and increase the load factor. Simulations are conducted on low- and medium-voltage......This paper presents a novel controller design for controlling appliances based on local measurements of voltage. The controller finds the normalized voltage deviation accounting for the sensitivity of voltage measurements to appliance state. The controller produces a signal indicating desired power...... distribution systems with residential loads including voltage-sensitive water heaters. In low-voltage systems, the results of the simulations show the controller to be effective at reducing the extremes of voltage and increasing the load factor while respecting end-use temperature constraints. In medium-voltage...

  15. Application of carbon nanotube hold-off voltage for determining gas composition

    Science.gov (United States)

    Schipper, John F. (Inventor); Li, Jing (Inventor)

    2009-01-01

    Method and system for determining chemical composition of a single-component or multiple-component gas, using a discharge holdoff mechanism. A voltage difference V between two spaced apart electrodes is brought to a selected value and held, the holdoff time interval .DELTA.t(V;ho) required before gas discharge occurs is measured, and the associated electrical current or cumulative electrical charge is measured. As the voltage difference V increases, the time interval length .DELTA.t(V;ho) decreases monotonically. Particular voltage values, V.sub..infin. and V.sub.0, correspond to initial appearance of discharge (.DELTA.t.apprxeq..infin.) and prompt discharge (.DELTA.t.apprxeq.0). The values V.sub..infin. and V.sub.0 and the rate of decrease of .DELTA.t(V;ho) and/or the rate of increase of current or cumulative charge with increasing V are characteristic of one or more gas components present.

  16. A method for the manufacture of electrodes

    OpenAIRE

    Kervenic, Y.V.; van der Zant, S.J.; Morpurgo, A.; Gurevich, L.; Kouwenhoven, L. P.

    2003-01-01

    A method of reducing the distance between electrodes, comprising the growth of electrodes by means of electrodeposition in a solution, wherein during the process of growth the conductance over the electrodes is measured and the method is terminated when the conductance has reached a predetermined value. The method according to the invention is characterised in that measuring arrangement for measuring the conductance is suitable for measuring an electric current between the electrodes when the...

  17. Geometrical Shape Investigation For Electrodes in Silent Discharge Chamber

    Science.gov (United States)

    Facta, Mochammad; Ayu Ketut Umiati, Ngurah; Warsito, Agung

    2017-04-01

    Silent discharge is the most prominent method to carry out plasma reaction because. discharge is easily initiated by injecting alternating current in high voltage to the pair of separated electrodes. The electron emission from surface of dielectric placed on instantaneous cathode is stimulated by ion induced electron emission. In this method, spark is avoided by placing insulation material to either one or both of the electrodes. In practical, it is very difficult to determine the exact limit of the voltage that initiate the discharge by mathematical analysis because it depends on many factors, namely dimensions, type and geometrical shapes of electrode, thickness of insulation, and type of electric field inside the discharge gap. To get lower initial voltage for discharge, it is important to find the best geometrical shape of electrode in relation to skin effect that trigger electron emission. This work investigates the behaviour of charges, current, electric field and voltage surrounding electrodes with various geometrical shape.

  18. The smooth transition from field emission to a self-sustained plasma in microscale electrode gaps at atmospheric pressure

    Science.gov (United States)

    Bilici, Mihai A.; Haase, John R.; Boyle, Calvin R.; Go, David B.; Sankaran, R. Mohan

    2016-06-01

    We report on the existence of a smooth transition from field emission to a self-sustained plasma in microscale electrode geometries at atmospheric pressure. This behavior, which is not found at macroscopic scales or low pressures, arises from the unique combination of large electric fields that are created in microscale dimensions to produce field-emitted electrons and the high pressures that lead to collisional ionization of the gas. Using a tip-to-plane electrode geometry, currents less than 10 μA are measured at onset voltages of ˜200 V for gaps less than 5 μm, and analysis of the current-voltage (I-V) relationship is found to follow Fowler-Nordheim behavior, confirming field emission. As the applied voltage is increased, gas breakdown occurs smoothly, initially resulting in the formation of a weak, partial-like glow and then a self-sustained glow discharge. Remarkably, this transition is essentially reversible, as no significant hysteresis is observed during forward and reverse voltage sweeps. In contrast, at larger electrode gaps, no field emission current is measured and gas breakdown occurs abruptly at higher voltages of ˜400 V, absent of any smooth transition from the pre-breakdown condition and is characterized only by glow discharge formation.

  19. The smooth transition from field emission to a self-sustained plasma in microscale electrode gaps at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Bilici, Mihai A.; Boyle, Calvin R.; Sankaran, R. Mohan, E-mail: dgo@nd.edu, E-mail: mohan@case.edu [Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, Ohio 44106 (United States); Haase, John R. [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Go, David B., E-mail: dgo@nd.edu, E-mail: mohan@case.edu [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2016-06-14

    We report on the existence of a smooth transition from field emission to a self-sustained plasma in microscale electrode geometries at atmospheric pressure. This behavior, which is not found at macroscopic scales or low pressures, arises from the unique combination of large electric fields that are created in microscale dimensions to produce field-emitted electrons and the high pressures that lead to collisional ionization of the gas. Using a tip-to-plane electrode geometry, currents less than 10 μA are measured at onset voltages of ∼200 V for gaps less than 5 μm, and analysis of the current–voltage (I-V) relationship is found to follow Fowler–Nordheim behavior, confirming field emission. As the applied voltage is increased, gas breakdown occurs smoothly, initially resulting in the formation of a weak, partial-like glow and then a self-sustained glow discharge. Remarkably, this transition is essentially reversible, as no significant hysteresis is observed during forward and reverse voltage sweeps. In contrast, at larger electrode gaps, no field emission current is measured and gas breakdown occurs abruptly at higher voltages of ∼400 V, absent of any smooth transition from the pre-breakdown condition and is characterized only by glow discharge formation.

  20. Voltage Sensors Monitor Harmful Static

    Science.gov (United States)

    2009-01-01

    A tiny sensor, small enough to be worn on clothing, now monitors voltage changes near sensitive instruments after being created to alert Agency workers to dangerous static buildup near fuel operations and avionics. San Diego s Quasar Federal Systems received a Small Business Innovation Research (SBIR) contract from Kennedy Space Center to develop its remote voltage sensor (RVS), a dime-sized electrometer designed to measure triboelectric changes in the environment. One of the unique qualities of the RVS is that it can detect static at greater distances than previous devices, measuring voltage changes from a few centimeters to a few meters away, due to its much-improved sensitivity.

  1. Voltage Management in Unbalanced Low Voltage Networks Using a Decoupled Phase-Tap-Changer Transformer

    OpenAIRE

    Coppo, Massimiliano; Turri, Roberto; Marinelli, Mattia; Han, Xue

    2014-01-01

    The paper studies a medium voltage-low voltage transformer with a decoupled on load tap changer capability on each phase. The overall objective is the evaluation of the potential benefits on a low voltage network of such possibility. A realistic Danish low voltage network is used for the analysis. The load profiles are characterized by using single phase measurement data on voltages, currents and active powers with a 10 minutes resolution. Different scenarios are considered: no tap action, th...

  2. Current-voltage-temperature characteristics of DNA origami

    Energy Technology Data Exchange (ETDEWEB)

    Bellido, Edson P; Bobadilla, Alfredo D; Rangel, Norma L; Seminario, Jorge M [Department of Chemical Engineering, Texas A and M University, College Station, TX 77843 (United States); Zhong Hong; Norton, Michael L [Department of Chemistry, Marshall University, Huntington, WV 25755 (United States); Sinitskii, Alexander [Department of Chemistry, Rice University, Houston, TX 77005 (United States)

    2009-04-29

    The temperature dependences of the current-voltage characteristics of a sample of triangular DNA origami deposited in a 100 nm gap between platinum electrodes are measured using a probe station. Below 240 K, the sample shows high impedance, similar to that of the substrate. Near room temperature the current shows exponential behavior with respect to the inverse of temperature. Sweep times of 1 s do not yield a steady state; however sweep times of 450 s for the bias voltage secure a steady state. The thermionic emission and hopping conduction models yield similar barriers of {approx}0.7 eV at low voltages. For high voltages, the hopping conduction mechanism yields a barrier of 0.9 eV and the thermionic emission yields 1.1 eV. The experimental data set suggests that the dominant conduction mechanism is hopping in the range 280-320 K. The results are consistent with theoretical and experimental estimates of the barrier for related molecules.

  3. Sampling membrane potential, membrane resistance and electrode resistance with a glass electrode impaled into a single cell.

    Science.gov (United States)

    Schiebe, M; Jaeger, U

    1980-04-01

    A method is demonstrated to measure membrane resistances and membrane potentials of single cells during impalement by a single glass microelectrode. The intention was to develop a procedure which would provide data almost continuously. Therefore, a frequency-dependent voltage divider network has been chosen to represent the basic electrical properties of the electrode and cell membrane, and used to explore its voltage response to a current stimulus, consisting of two rectangular pulses of different widths. It can be shown that the resolution of the method can be improved by inverting this stimulus so that each polarization becomes a relaxation and vice versa. In order to generate, analyze and display this signal continuously, a device has been designed which has been called 'Electrophysiological Monitor, (E1M2)'. E1M2 provides a current stimulus as input into a standard bridge network and can analyze the summed response of the electrode and cell by a set of sample-hold amplifiers. It then decodes and displays the data continuously, as membrane potential (Em), input resistance of the cell (Rinp) and the electrode resistance (Re) respectively. From Rinp the membrane resistance (Rm) can be deduced. The validity of the method has been examined by measuring these parameters in frog muscle cells. Technical design considerations, the accuracy and possible pitfalls with the suggested procedure are discussed.

  4. High voltage load resistor array

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Monty Ray [Smithfield, VA

    2005-01-18

    A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

  5. Temperature and bias voltage dependence of Co/Pd multilayer-based magnetic tunnel junctions with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, Zoe, E-mail: zkugler@physik.uni-bielefeld.d [Bielefeld University, Department of Physics, Universitaetsstr. 25, 33615 Bielefeld (Germany); Drewello, Volker; Schaefers, Markus; Schmalhorst, Jan; Reiss, Guenter; Thomas, Andy [Bielefeld University, Department of Physics, Universitaetsstr. 25, 33615 Bielefeld (Germany)

    2011-01-15

    Temperature- and bias voltage-dependent transport measurements of magnetic tunnel junctions (MTJs) with perpendicularly magnetized Co/Pd electrodes are presented. Magnetization measurements of the Co/Pd multilayers are performed to characterize the electrodes. The effects of the Co layer thickness in the Co/Pd bilayers, the annealing temperature, the Co thickness at the MgO barrier interface, and the number of bilayers on the tunneling magneto resistance (TMR) effect are investigated. TMR-ratios of about 11% at room temperature and 18.5% at 13 K are measured and two well-defined switching fields are observed. The results are compared to measurements of MTJs with Co-Fe-B electrodes and in-plane anisotropy.

  6. Design, fabrication and evaluation of a conforming circumpolar peripheral nerve cuff electrode for acute experimental use.

    Science.gov (United States)

    Foldes, Emily L; Ackermann, D Michael; Bhadra, Niloy; Kilgore, Kevin L; Bhadra, Narendra

    2011-03-15

    Nerve cuff electrodes are a principle tool of basic and applied electro-neurophysiology studies and are championed for their ability to achieve good nerve recruitment with low thresholds. We describe the design and method of fabrication for a novel circumpolar peripheral nerve electrode for acute experimental use. This cylindrical cuff-style electrode provides approximately 270° of radial electrode contact with a nerve for each of an arbitrary number of contacts, has a profile that allows for simple placement and removal in an acute nerve preparation, and is designed for adjustment of the cylindrical diameter to ensure a close fit on the nerve. For each electrode, the electrical contacts were cut from 25 μm platinum foil as an array so as to maintain their positions relative to each other within the cuff. Lead wires were welded to each intended contact. The structure was then molded in silicone elastomer, after which the individual contacts were electrically isolated. The final electrode was curved into a cylindrical shape with an inner diameter corresponding to that of the intended target nerve. The positions of these contacts were well maintained during the molding and shaping process and failure rates during fabrication due to contact displacements were very low. Established electrochemical measurements were made on one electrode to confirm expected behavior for a platinum electrode and to measure the electrode impedance to applied voltages at different frequencies. These electrodes have been successfully used for nerve stimulation, recording, and conduction block in a number of different acute animal experiments by several investigators.

  7. All-carbon multi-electrode array for real-time in vitro measurements of oxidizable neurotransmitters

    CERN Document Server

    Picollo, F; Bernardi, E; Plaitano, M; Franchino, C; Gosso, S; Pasquarelli, A; Carbone, E; Olivero, P; Carabelli, V

    2016-01-01

    We report on the ion beam fabrication of all-carbon multi electrode arrays (MEAs) based on 16 graphitic micro-channels embedded in single-crystal diamond (SCD) substrates. The fabricated SCD-MEAs are systematically employed for the in vitro simultaneous amperometric detection of the secretory activity from populations of chromaffin cells, demonstrating a new sensing approach with respect to standard techniques. The biochemical stability and biocompatibility of the SCD-based device combined with the parallel recording of multi-electrodes array allow: i) a significant time saving in data collection during drug screening and/or pharmacological tests over a large number of cells, ii) the possibility of comparing altered cell functionality among cell populations, and iii) the repeatition of acquisition runs over many cycles with a fully non-toxic and chemically robust bio-sensitive substrate.

  8. The fabrication and characterization of adjustable nanogaps between gold electrodes on chip for electrical measurement of single molecules

    Energy Technology Data Exchange (ETDEWEB)

    Tian Jinghua; Yang Yang; Liu Bo; Wu Deyin; Tian Zhongqun [State Key Laboratory of Physical Chemistry of Solid Surfaces and LIA CNRS XiamENS ' NanoBioChem' , College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian (China); Schoellhorn, Bernd; Maisonhaute, Emmanuel; Muns, Anna Serra; Chen Yong; Amatore, Christian [UMR CNRS 8640 ' PASTEUR' and LIA CNRS XiamENS ' NanoBioChem' , Ecole Normale Superieure, Universite Pierre et Marie Curie-Paris 6, 24 rue Lhomond, 75231 Paris Cedex 05 (France); Tao, Nong-Jian, E-mail: zqtian@xmu.edu.cn, E-mail: christian.amatore@ens.fr [Ira A Fulton School of Engineering and Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287-6206 (United States)

    2010-07-09

    This work reports on a new method to fabricate mechanically controllable break junctions (MCBJ) with finely adjustable nanogaps between two gold electrodes on solid state chips for characterizing electron transport properties of single molecules. The simple, low cost, robust and reproducible fabrication method combines conventional photolithography, chemical etching and electrodeposition to produce suspended electrodes separated with nanogaps. The MCBJ devices fabricated by the method can undergo many cycles in which the nanogap width can be precisely and repeatedly varied from zero to several nanometers. The method improves the success rate of the MCBJ experiments. Using these devices the electron transport properties of a typical molecular system, commercially available benzene-1,4-dithiol (BDT), have been studied. The I-V and G-V characteristic curves of BDT and the conductance value for a single BDT molecule established the excellent device suitability for molecular electronics research.

  9. A Novel Dual-Electrode Plug to Achieve Intensive Electric Field for High Performance Ignition

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A thorough analysis of electric field is carried out so as to verify that a novel dual-electrode plug can build intensive electric field and can improve the main drawbacks of feeble electric field and low ignition efficiency of the traditional plug. With intensive electric field, the proposed novel plug can achieve high performance ignition, resulting in fuel saving and exhaust reduction. Gauss law is applied for electric field analysis to show that intensive electric field can be built by the novel plug. Then, according to Faraday law a lower-voltage ignition feature accomplished by the plug is discussed. Compared with traditional plug, the novel dual-electrode plug has the following advantages. (1 Much higher energy density is built between the plug electrodes, lowering ignition voltage requirement. (2 Electromagnetic interference (EMI problem caused by high ignition voltage is readily resolved. (3 Ignition time delay can be improved. (4 The feature to save fuel consuming is achieved. (5 The exhaust of CO and HC is reduced significantly. Practical measurements are fulfilled to validate the electric field analysis and to demonstrate the features of the proposed dual-electrode plug.

  10. Origin of the transition voltage in gold–vacuum–gold atomic junctions

    KAUST Repository

    Wu, Kunlin

    2012-12-13

    The origin and the distance dependence of the transition voltage of gold-vacuum-gold junctions are investigated by employing first-principles quantum transport simulations. Our calculations show that atomic protrusions always exist on the electrode surface of gold-vacuum-gold junctions fabricated using the mechanically controllable break junction (MCBJ) method. The transition voltage of these gold-vacuum-gold junctions with atomically sharp electrodes is determined by the local density of states (LDOS) of the apex gold atom on the electrode surface rather than by the vacuum barrier shape. More specifically, the absolute value of the transition voltage roughly equals the rising edge of the LDOS peak contributed by the 6p atomic orbitals of the gold atoms protruding from the electrode surface, whose local Fermi level is shifted downwards when a bias voltage is applied. Since the LDOS of the apex gold atom depends strongly on the exact shape of the electrode, the transition voltage is sensitive to the variation of the atomic configuration of the junction. For asymmetric junctions, the transition voltage may also change significantly depending on the bias polarity. Considering that the occurrence of the transition voltage requires the electrode distance to be larger than a critical value, the interaction between the two electrodes is actually rather weak. Consequently, the LDOS of the apex gold atom is mainly determined by its local atomic configuration and the transition voltage only depends weakly on the electrode distance as observed in the MCBJ experiments. © 2013 IOP Publishing Ltd.

  11. Origin of the transition voltage in gold-vacuum-gold atomic junctions.

    Science.gov (United States)

    Wu, Kunlin; Bai, Meilin; Sanvito, Stefano; Hou, Shimin

    2013-01-18

    The origin and the distance dependence of the transition voltage of gold-vacuum-gold junctions are investigated by employing first-principles quantum transport simulations. Our calculations show that atomic protrusions always exist on the electrode surface of gold-vacuum-gold junctions fabricated using the mechanically controllable break junction (MCBJ) method. The transition voltage of these gold-vacuum-gold junctions with atomically sharp electrodes is determined by the local density of states (LDOS) of the apex gold atom on the electrode surface rather than by the vacuum barrier shape. More specifically, the absolute value of the transition voltage roughly equals the rising edge of the LDOS peak contributed by the 6p atomic orbitals of the gold atoms protruding from the electrode surface, whose local Fermi level is shifted downwards when a bias voltage is applied. Since the LDOS of the apex gold atom depends strongly on the exact shape of the electrode, the transition voltage is sensitive to the variation of the atomic configuration of the junction. For asymmetric junctions, the transition voltage may also change significantly depending on the bias polarity. Considering that the occurrence of the transition voltage requires the electrode distance to be larger than a critical value, the interaction between the two electrodes is actually rather weak. Consequently, the LDOS of the apex gold atom is mainly determined by its local atomic configuration and the transition voltage only depends weakly on the electrode distance as observed in the MCBJ experiments.

  12. High Voltage Seismic Generator

    Science.gov (United States)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  13. Test of PPV and kVp magnitudes using a non invasive voltage test aiming an improvement on the measurement acquisition; Testes das grandezas PPV e kVp utilizando um medidor de tensao nao invasivo visando um aperfeicoamento na aquisicao de medidas

    Energy Technology Data Exchange (ETDEWEB)

    Lucena, Rodrigo F. de; Dias, Daniel M.; Franciscatto, Priscila C.; Correa, Eduardo de L.; Vivolo, Vitor; Potiens, Maria da Penha A., E-mail: rodrigoifusp@yahoo.com.b, E-mail: dmdias@ipen.b, E-mail: pfranciscatto@yahoo.com.b, E-mail: edu1905@gmail.co, E-mail: vivolo@ipen.b, E-mail: mppalbu@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    In this work the measurements of PPV (Practical Peak Voltage) and kVp (Peak Voltage) were studied obtained by use of voltage non invasive, under different conditions, viewing an improvement on the acquisition measurements at the Instrument Calibration Laboratory of the IPEN, Sao Paulo, Brazil, for the implantation of the radiation quality required for the required calibrations for X radiation instruments

  14. Measurement and Calculation of Electrochemical Potentials in Hydrogenated High Temperature Water, including an Evaluation of the Yttria-Stabilized Zirconia/Iron-Iron Oxide (Fe/Fe3O4) Probe as Reference Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Steven A. Attanasio; David S. Morton; Mark A. Ando

    2001-10-22

    The importance of knowing the electrochemical corrosion potential (ECP, also referred to as E{sub con}) of nickel-base alloys in hydrogenated water is related to the need to understand the effects of dissolved (i.e., aqueous) hydrogen concentration ([H{sub 2}]) on primary water stress corrosion cracking (PWSCC). Also, the use of a reference electrode (RE) can improve test quality by heightening the ability to detect instances of out-of-specification or unexpected chemistry. Three methods are used to measure and calculate the ECP of nickel-based alloys in hydrogenated water containing {approx} 1 to 150 scc/kg H{sub 2} (0.1 to 13.6 ppm H{sub 2}) at 260 to 360 C. The three methods are referred to as the specimen/component method, the platinum (Pt) method, and the yttria-stabilized zirconia/iron-iron oxide (YSZ/Fe-Fe{sub 3}O{sub 4}) RE method. The specimen/component method relies upon the assumption that the specimen or component behaves as a hydrogen electrode, and its E{sub corr} is calculated using the Nernst equation. The present work shows that this method is valid for aqueous H{sub 2} levels {ge} {approx} 5 to 10 scc/kg H{sub 2}. The Pt method uses a voltage measurement between the specimen or component and a Pt electrode, with the Pt assumed to behave as a hydrogen electrode; this method is valid as long as the aqueous H{sub 2}level is known. The YSZ/Fe-Fe{sub 3}O{sub 4}, which represents a relatively new approach for measuring E{sub corr} in this environment, can be used even if the aqueous H{sub 2} level is unknown. The electrochemical performance of the YSZ/Fe-Fe{sub 3}O{sub 4} probe supports its viability as a RE for use in high temperature hydrogenated water. Recent design modifications incorporating a teflon sealant have improved the durability of this RE (however, some of the REs do still fail prematurely due to water in-leakage). The Pt method is judged to represent the best overall approach, though there are cases where the other methods are superior

  15. Current Analysis and Modification Measures of High Voltage Synchronous Motor Shaft%高压同步电机轴电流分析及改装措施

    Institute of Scientific and Technical Information of China (English)

    侯江继

    2014-01-01

    通过现场高压同步电机与焦炉气压缩机轴瓦烧损的故障处理,分析了轴电流产生的原因及电机和焦炉气压缩机滑动轴瓦的危害,并提出防止电机产生轴电流电腐蚀的有效措施。%Through the fault processing of the burned field high voltage synchronous motor and coke oven gas compressor, this paper analyzes the cause of the shaft current and its hazard on motor and coke oven gas compressor sliding bearing, and puts forward some effective measures to prevent the motor shaft current electric corrosion.

  16. Measurements of the salt-removal of NaCl, KCl and MgCl using a carbon electrode prepared with freezing thawing method in capacitive deionization

    Science.gov (United States)

    Endarko, Sari, Intan Permata; Fatimah, Iim

    2016-04-01

    Carbon electrodes prepared with freezing thawing method for desalination purpose has been synthesized and characterized. The carbon electrodes were prepared with an activated carbon (700 - 1400 m2/g) and polyvinyl alcohol (PVA) as a binder using freezing thawing method with 3 and 4 cycles (1 cycle is 12 hours for freezing and 12 hours for thawing). Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to analyze their electrochemical properties. The main study was to measure the salt-removal of 180 µS/cm NaCl, MgCl and KCl using a capacitive deionization (CDI) unit cell with five pairs of carbon electrodes. The applied potential of 2.0 V and a flow rate of 25 mL/min were used to desalination tests, the result showed that the salt-removal percentage of KCl solution has greater than NaCl and MgCl. The highest value for the salt-removal of NaCl, KCl and MgCl can be achieved for the freezing thawing method with 4 cycles. The salt-removal percentage of KCl was achieved at 64.10% whilst resulted in 54.30 and 54.47 % for NaCl and MgCl, respectively.

  17. High-precision mass measurements of neutron-deficient Tl isotopes at ISOLTRAP and the development of an ultra-stable voltage source for the PENTATRAP experiment

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Christine

    2015-01-14

    Atomic masses and hence binding energies of nuclides are of great importance for studies of nuclear structure since they reflect all effective interactions in a nucleus. Within this thesis the masses of seven nuclides, namely {sup 194}Au, {sup 194}Hg, {sup 190,193,198}Tl and {sup 202,208}Pb, were determined at the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The thallium region in the chart of isotopes is of special interest due to the occurrence of nuclear structure effects like low-lying isomers, level inversion, shape coexistence and deformations. These effects are investigated by applying finite-difference mass formulas, such as the two-neutron separation energies or the so-called empirical pairing gaps. The second topic addressed within the present thesis is an ultra-stable voltage source, called StaReP (Stable Reference for Penning Trap Experiments), which was developed at the Max-Planck-Institut fuer Kernphysik. It is one of the key components of the high-precision mass spectrometer PENTATRAP, containing a tower of five Penning traps. A 25-channel voltage source with a relative stability of few 10{sup -8} over a period of 10 minutes in the range of 0 to -100V is mandatory for PENTATRAP aiming for mass measurements with relative mass uncertainties of ≤ 10{sup -11}. Mass values with such a high precision allow for stringent tests of quantum electrodynamics in strong electric fields, testing Einstein's mass-energy relation E = mc{sup 2} as well as measurements of decay energies (Q-values) with applications in neutrino physics.

  18. Use of Surface Photovoltage Spectroscopy to Measure Built-in Voltage, Space Charge Layer Width, and Effective Band Gap in CdSe Quantum Dot Films.

    Science.gov (United States)

    Zhao, Jing; Nail, Benjamin A; Holmes, Michael A; Osterloh, Frank E

    2016-09-01

    Surface photovoltage spectroscopy (SPS) was used to study the photochemistry of mercaptoethanol-ligated CdSe quantum dot (2.0-4.2 nm diameter) films on indium doped tin oxide (ITO) in the absence of an external bias or electrolyte. The n-type films generate negative voltages under super band gap illumination (0.1-0.5 mW cm(-2)) by majority carrier injection into the ITO substrate. The photovoltage onset energies track the optical band gaps of the samples and are assigned as effective band gaps of the films. The photovoltage values (-125 to -750 mV) vary with quantum dot sizes and are modulated by the built-in potential of the CdSe-ITO Schottky type contacts. Deviations from the ideal Schottky model are attributed to Fermi level pinning in states approximately 1.1 V negative of the ITO conduction band edge. Positive photovoltage signals of +80 to +125 mV in films of >4.0 nm nanocrystals and in thin (70 nm) nanocrystal films are attributed to electron-hole (polaron) pairs that are polarized by a space charge layer at the CdSe-ITO boundary. The space charge layer is 70-150 nm wide, based on thickness-dependent photovoltage measurements. The ability of SPS to directly measure built-in voltages, space charge layer thickness, sub-band gap states, and effective band gaps in drop-cast quantum dot films aids the understanding of photochemical charge transport in quantum dot solar cells.

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

    OpenAIRE

    Fu-an Guo; Guoqiang Li; Weifeng Zhang

    2010-01-01

    Dye-sensitized solar cells (DSSCs) are fabricated with perovskite-type BaSnO3 as the photoelectrode materials. Different preparation methods including coprecipitation, hydrothermal, and solid state reaction are employed to synthesize BaSnO3 particles to optimize the photoelectric activities of electrode materials. The photoelectric properties of BaSnO3 particles and the performances of DSSCs are investigated by surface photovoltage spectroscopy and current-voltage measurements. The light-to-e...

  20. Chemical treatments of the nanocrystalline porous TiO2 electrodes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two types of nanocrystalline porous TiO2 electrodes were prepared by the hydrothermal and painting methods. The incident photon-to-current efficiency and photoelectrical conversion efficiency were both improved by chemical treatments of titanium tetrachloride and titanium isopropoxide. The surface roughness, quantities of adsorbed dye, photocurrent-voltage curves, IR spectra and UV-visible absorption spectra were measured, and the mechanism of chemical treatments was discussed.