Artigos de revistas: "Ion current measurements"

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ONUMA, Yoshiaki, Norihiko YOSHIKAWA, Masahiko UMETANI e Kaszuhiro KIMURA. "Ion current measurements in turbulent diffusion flames." Transactions of the Japan Society of Mechanical Engineers Series B 52, n.º 475 (1986): 1151–57. http://dx.doi.org/10.1299/kikaib.52.1151.

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Gaus, A. D., W. T. Htwe, J. A. Brand, T. J. Gay e M. Schulz. "Energy spread and ion current measurements of several ion sources". Review of Scientific Instruments 65, n.º 12 (dezembro de 1994): 3739–45. http://dx.doi.org/10.1063/1.1144500.

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Muzyukin, I. L., e P. S. Mikhailov. "The measurements of vacuum arc behaviour at threshold current". Journal of Physics: Conference Series 2064, n.º 1 (1 de novembro de 2021): 012015. http://dx.doi.org/10.1088/1742-6596/2064/1/012015.

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Abstract The measurements of vacuum arc current parameters at the threshold current were made. The threshold currents for Cu, W, graphite cathodes were measured. It was shown that the current that vacuum arc chops with, has a statistical distribution. The vacuum arc current chopping is accompanied with significant ion current burst. The ion current of W and Cu cathodes contains intensive peaks with 30-50 ns duration. It was shown that the cathode materials that have intense peaks have a significant threshold current.

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Belianinov, Alex, Songkil Kim, Cannon Buechley, Matthew Burch, Olga Ovchinnikova e Stephen Jesse. "Ion Beam Induced Current Measurements of Solar Cells with Helium Ion Microscopy". Microscopy and Microanalysis 23, S1 (julho de 2017): 2084–85. http://dx.doi.org/10.1017/s1431927617011084.

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Wollgarten, J. Christopher, Nikolaos Zarzalis, Fabio Turrini e Antonio Peschiulli. "Experimental investigations of ion current in liquid-fuelled gas turbine combustors". International Journal of Spray and Combustion Dynamics 9, n.º 3 (5 de maio de 2017): 172–85. http://dx.doi.org/10.1177/1756827716688477.

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This work covers investigations of the static and dynamic behaviour of a confined, co-swirled and liquid-fuelled airblast injection system. The focus lies on the application of ion current sensors for the qualitative measurement of the heat release rate or for flame monitoring purposes in complex technical combustion processes. The ion current sensor is to operate in a feedback control loop in order to react on combustion dynamics in real time. The first part of the work analyses experimental data, which were obtained with different techniques, e.g. dynamic pressure, chemiluminescence, fine-wire thermocouples and ion current. The results show that the thermo-acoustic instability and the precessing vortex core generate an interaction mode. The frequency of this interaction mode is the difference of the other two modes. This has not yet been observed for partially premixed and liquid-fuelled injection systems before and also was not detected by the chemiluminescence of the flame. The ion current measurement technique is able to detect the helical mode of the precessing vortex core as well as the interaction frequency, leading to the conclusion that the chemical reactions are influenced by this helical structure. Contour maps of the frequencies reveal this influence in the outer shear layer. The second part of the study focused on the ion current probe as a method to predict static combustion instabilities, such as lean blowout. According to the results, the ion current is a fast responding method to detect lean blowout, provided that the detector is mounted at a suitable position. Measurements at different positions in the flame were compared with phase-locked chemiluminescence measurements. Precursors in the ion current signal for lean-blowout prediction were found using a statistical approach, which is based on ion peak distance. The precursor events allow for the use of this approach with a feedback control loop in future applications.

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Urban, Radovan, Robert A. Wolkow e Jason L. Pitters. "Evaluating Angular Ion Current Density for Atomically Defined Nanotips". Microscopy and Microanalysis 20, n.º 5 (10 de julho de 2014): 1514–20. http://dx.doi.org/10.1017/s1431927614001627.

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AbstractIn this paper we investigate methods to characterize angular current density from atomically defined gas field ion sources. We show that the ion beam emitted from a single apex atom is described by a two-dimensional Gaussian profile. Owing to the Gaussian shape of the beam and the requirement to collect the majority of the ion current, fixed apertures have inhomogeneous illumination. Therefore, angular current density measurements through a fixed aperture record averaged angular current density. This makes comparison of data difficult as averaged angular current density depends on aperture size. For the same reasons, voltage normalization cannot be performed for fixed aperture measurements except for aperture sizes that are infinitely small. Consistent determination of angular current density and voltage normalization, however, can be achieved if the beam diameter as well as total ion current are known. In cases where beam profile cannot be directly imaged with a field ion microscope, the beam profile could be extracted from measurements taken at multiple acceleration voltages and/or with multiple aperture sizes.

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Rawat, Bharat Singh, S. K. Sharma, B. Choksi, V. Prahlad e U. K. Baruah. "Measurement system for ion beam profiles using fixed parallel wires and Faraday cup array". AIP Advances 12, n.º 12 (1 de dezembro de 2022): 125103. http://dx.doi.org/10.1063/5.0117836.

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The radial profiles of ion current density are measured using a combination of two techniques—fixed parallel wires and a Faraday cup array—in a ring cusp ion source. These measurements are carried out for Ar+ ion beam current in the range of 20–90 mA and energy in the range of 850–1650 eV. Current density profiles near the extraction plane of the ion source are obtained by Abel inversion of the profiles of current measured using the parallel wires. In addition, the Faraday cup array provides radial profiles of ion current density at two different locations along the beam axis. A numerical model is developed and utilized for estimating the beam divergence and focal length from the profiles of ion current density measured using the two techniques. A fixed parallel wire array is established as an effective method for monitoring the ion beam profiles close to the ion source's extraction plane when the ion beam is utilized for other applications. The performance of the two measurement techniques is compared by estimating the ion beam current from the measurement of ion current density with the beam current measured from the power supply.

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Jimbo, Kouichi, e Masashi Iima. "Negative ion current measurements with the modified JAERI probe". Review of Scientific Instruments 62, n.º 3 (março de 1991): 772–74. http://dx.doi.org/10.1063/1.1142082.

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Narula, H. S., e J. G. Harris. "A time-based VLSI potentiostat for ion current measurements". IEEE Sensors Journal 6, n.º 2 (abril de 2006): 239–47. http://dx.doi.org/10.1109/jsen.2006.870142.

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Soares, Rudi, Alexander Bessman, Oskar Wallmark, Göran Lindbergh e Pontus Svens. "An Experimental Setup with Alternating Current Capability for Evaluating Large Lithium-Ion Battery Cells". Batteries 4, n.º 3 (13 de agosto de 2018): 38. http://dx.doi.org/10.3390/batteries4030038.

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In the majority of applications using lithium-ion batteries, batteries are exposed to some harmonic content apart from the main charging/discharging current. The understanding of the effects that alternating currents have on batteries requires specific characterization methods and accurate measurement equipment. The lack of commercial battery testers with high alternating current capability simultaneously to the ability of operating at frequencies above 200 Hz, led to the design of the presented experimental setup. Additionally, the experimental setup expands the state-of-the-art of lithium-ion batteries testers by incorporating relevant lithium-ion battery cell characterization routines, namely hybrid pulse power current, incremental capacity analysis and galvanic intermittent titration technique. In this paper the hardware and the measurement capabilities of the experimental setup are presented. Moreover, the measurements errors due to the setup’s instruments were analysed to ensure lithium-ion batteries cell characterization quality. Finally, this paper presents preliminary results of capacity fade tests where 28 Ah cells were cycled with and without the injection of 21 A alternating at 1 kHz. Up to 300 cycles, no significant fade in cell capacity may be measured, meaning that alternating currents may not be as harmful for lithium-ion batteries as considered so far.

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Lee, Y., R. A. Gough, W. B. Kunkel, K. N. Leung, L. T. Perkins, D. S. Pickard, L. Sun, J. Vujic, M. D. Williams e D. Wutte. "Ion energy spread and current measurements of the rf-driven multicusp ion source". Review of Scientific Instruments 68, n.º 3 (março de 1997): 1398–402. http://dx.doi.org/10.1063/1.1147948.

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Scharmann, Steffen, Konstantin Keil, Jana Zorn, Patrick Dietz, Benny Nauschütt, Kristof Holste, Klaus Hannemann et al. "Thrust measurement of an ion thruster by a force probe approach and comparison to a thrust balance". AIP Advances 12, n.º 4 (1 de abril de 2022): 045218. http://dx.doi.org/10.1063/5.0066401.

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A key parameter when characterizing the performance of an electric propulsion system is obviously its thrust. The thrust can be either determined directly using a so-called thrust balance or deduced from indirect measurements. Here, we present a comparison of thrust measurements of the same radio frequency ion thruster in the thrust range from 250 μN to 1.5 mN using three different approaches: a conventional direct measurement employing a thrust balance and two indirect measurements, one based on a force probe located stationary in the thruster’s plume in conjunction with a scan of the ion beam profile using a Faraday-array scanner, and another one based on a measurement of the beam current at the grid system and a correction for beam divergence deduced from the Faraday-array scans. The results of the three approaches are compared for different beam currents, and pros and cons of the approaches are discussed.

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Von Reden, Karl F., Ann P. McNichol, Ann Pearson e Robert J. Schneider. "14C AMS Measurements of <100 μG Samples with a High-Current System". Radiocarbon 40, n.º 1 (1997): 247–53. http://dx.doi.org/10.1017/s0033822200018117.

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The NOSAMS facility at Woods Hole Oceanographic Institution has started to develop and apply techniques for measuring very small samples on a standard Tandetron accelerator mass spectrometry (AMS) system with high-current hemispherical Cs sputter ion sources. Over the past year, results on samples ranging from 7 to 160 μg C showed both the feasibility of such analyses and the present limitations on reducing the size of solid carbon samples. One of the main factors affecting the AMS results is the dependence of a number of the beam optics parameters on the extracted ion beam current. The extracted currents range from 0.5 to 10 μA of 12C− for the sample sizes given above. We here discuss the setup of the AMS system and methods for reliable small-sample measurements and give the AMS-related limits to sample size and the measurement uncertainties.

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Viitanen, A. K., E. Saukko, H. Junninen, S. Rantanen, M. Kulmala, A. Virtanen e J. M. Mäkelä. "Atmospheric trace gas measurements using ion mobility spectrometer". Atmospheric Measurement Techniques Discussions 4, n.º 4 (4 de agosto de 2011): 4957–90. http://dx.doi.org/10.5194/amtd-4-4957-2011.

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Abstract. Ion mobility spectrometer (IMS) was implemented to measure gas phase compounds from ambient air in order to study the suitability of the technique for on-line atmospheric measurements. The measurements took place at the SMEAR II station in Hyytiälä, Finland during spring periods on 2008 and 2009. We were able to separate several different atmosphere related ion mobility peaks form the measured ion mobility distributions. The hypothetic origins of these peaks are discussed accompanying the comparison with earlier trace gas measurements by different techniques. The potential of the IMS for atmospheric studies utilizing the concept used here was found out to be in monitoring the overall cleanness of prevailing atmospheric conditions as well as fast detection of the changes of those conditions. With further developing of the technique based on experience gathered in this study the IMS could be tuned to better respond to current measurement needs in atmospheric studies.

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Addabbo, Tommaso, Ada Fort, Elia Landi, Marco Mugnaini, Lorenzo Parri, Valerio Vignoli, Alessandro Zucca e Christian Romano. "Ion Current Sensor for Gas Turbine Condition Dynamical Monitoring: Modeling and Characterization". Sensors 21, n.º 20 (19 de outubro de 2021): 6944. http://dx.doi.org/10.3390/s21206944.

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This paper aims to thoroughly investigate the potential of ion current measurements in the context of combustion process monitoring in gas turbines. The study is targeted at characterizing the dynamic behavior of a typical ion-current measurement system based on a spark-plug. Starting from the preliminary study published in a previous work, the authors propose a refined model of the electrode (spark plug), based on the Langmuir probe theory, that incorporates the physical surface effects and proposes an optimized design of the conditioning electronics, which exploits a low frequency AC square wave biasing of the electrodes and allows for compensating some relevant parasitic effects. The authors present experimental results obtained in the laboratory, which allow for the evaluation of the validity of the model and the interpreting of the characteristics of the measurement signal. Finally, measurements carried out in the field on an industrial combustor are presented. The results confirm that the charged chemical species density sensed by the proposed measurement system and related to the mean value of the output signal is an indicator of the ‘average’ combustion process conditions in terms e.g., of air/fuel ratio, whereas the high frequency spectral component of the measured signal can give information related to the turbulent regime and to the presence of pressure pulsations. Results obtained with a prototype system demonstrated an achievable resolution of about 5 Pa on the estimated amplitude, even under small biasing voltage (22.5 V) and an estimated bandwidth of 10 kHz.

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Xie, He, Tomonori Saito e Michael A. Hickner. "Zeta Potential of Ion-Conductive Membranes by Streaming Current Measurements". Langmuir 27, n.º 8 (19 de abril de 2011): 4721–27. http://dx.doi.org/10.1021/la105120f.

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Akiyama, T., R. L. Boivin, M. W. Brookman, G. H. Degrandchamp, W. W. Heidbrink, C. M. Muscatello, R. I. Pinsker, K. E. Thome, B. Van Compernolle e M. A. Van Zeeland. "Fast wave interferometer for ion density measurement on DIII-D". Journal of Instrumentation 17, n.º 01 (1 de janeiro de 2022): C01052. http://dx.doi.org/10.1088/1748-0221/17/01/c01052.

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Abstract A fast wave interferometer (FWI), which can measure ion mass density, has been developed on DIII-D for its use on future fusion reactors, as well as for the study of ion behavior in current plasma devices. The frequency of the fast waves used for the FWI is around 60 MHz, and require antennas and coaxial cables or waveguides, which, unlike traditional mirror-based optical interferometers, are less susceptible to neutron/gamma-ray radiation and are relatively immune to impurity deposition and erosion as well as alignment issues. The bulk ion density evaluated using FWI show good agreement with that derived from CO2 interferometry within about 15%. When the ion mass density measurement by FWI is combined with an electron density measurement from CO2 interferometry, Z eff measurements are also enabled and are in agreement with those from visible Bremsstrahlung measurements. Additionally, large-bandwidth FWI measurements clearly resolve 10–100 kHz coherent modes and demonstrate its potential as a core fluctuation diagnostic, sensitive to both magnetic and ion density perturbations.

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Uchizono, N. M., R. E. Wirz, A. L. Collins, C. Marrese-Reading, S. M. Arestie e J. K. Ziemer. "A diagnostic for quantifying secondary species emission from electrospray devices". Review of Scientific Instruments 94, n.º 2 (1 de fevereiro de 2023): 025008. http://dx.doi.org/10.1063/5.0117666.

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Measuring the polydisperse beam of charged species emitted by an electrospray device requires accurate measurements of current. Secondary species emission (SSE) caused by high-velocity nanodroplet or molecular ion impacts on surfaces contributes to substantial uncertainty in current measurements. SSE consists of both positive and negative species; hence, mitigating measurement uncertainty requires different considerations other than plasma diagnostic techniques. The probe and analysis methods described herein distinguish between current contributions from positive SSE, negative SSE, and primary species. Separating each contribution provides positive and negative SSE yield measurements and corrected current measurements that reflect the true primary current. Sources of measurement uncertainty in probe design are discussed, along with appropriate mitigation methods. The probe and analysis techniques are demonstrated on an ionic liquid electrospray operating in a droplet emission mode to obtain an angular distribution of positive and negative SSE yields for an ionic liquid electrospray.

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MacCoss, Michael J., Michael J. Toth e Dwight E. Matthews. "Evaluation and Optimization of Ion-Current Ratio Measurements by Selected-Ion-Monitoring Mass Spectrometry". Analytical Chemistry 73, n.º 13 (julho de 2001): 2976–84. http://dx.doi.org/10.1021/ac010041t.

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Zhang, Huzhong, Detian Li, Peter Wurz, Adrian Etter, Yongjun Cheng, Changkun Dong e Weijun Huang. "Performance of a Low Energy Ion Source with Carbon Nanotube Electron Emitters under the Influence of Various Operating Gases". Nanomaterials 10, n.º 2 (18 de fevereiro de 2020): 354. http://dx.doi.org/10.3390/nano10020354.

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Low energy ion measurements in the vicinity of a comet have provided us with important information about the planet’s evolution. The calibration of instruments for thermal ions in the laboratory plays a crucial role when analysing data from in-situ measurements in space. A new low energy ion source based on carbon nanotube electron emitters was developed for calibrating the ion-mode of mass spectrometers or other ion detectors. The electron field emission (FE) properties of carbon nanotubes (CNTs) for H2, He, Ar, O2, and CO2 gases were tested in the experiments. H2, He, Ar, and CO2 adsorbates could change the FE temporarily at pressures from10−6 Pa to10−4 Pa. The FE of CNT remains stable in Ar and increases in H2, but degrades in He, O2, and CO2. All gas adsorbates lead to temporary degradation after working for prolonged periods. The ion current of the ion source is measured by using a Faraday cup and the sensitivity is derived from this measurement. The ion currents for the different gases were around 10 pA (corresponding to 200 ions/cm3 s) and an energy of ~28 eV could be observed.

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Séran, E. "Reconstruction of the ion plasma parameters from the current measurements: mathematical tool". Annales Geophysicae 21, n.º 5 (31 de maio de 2003): 1159–66. http://dx.doi.org/10.5194/angeo-21-1159-2003.

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Abstract. Instrument d’Analyse du Plasma (IAP) is one of the instruments of the newly prepared ionospheric mission Demeter. This analyser was developed to measure flows of thermal ions at the altitude of ~ 750 km and consists of two parts: (i) retarding potential analyser (APR), which is utilised to measure the energy distribution of the ion plasma along the sensor look direction, and (ii) velocity direction analyser (ADV), which is used to measure the arrival angle of the ion flow with respect to the analyser axis. The necessity to obtain quick and precise estimates of the ion plasma parameters has prompted us to revise the existing mathematical tool and to investigate different instrumental limitations, such as (i) finite angular aperture, (ii) grid transparency, (iii) potential depression in the space between the grid wires, (iv) losses of ions during their passage between the entrance diaphragm and the collector. Simple analytical expressions are found to fit the currents, which are measured by the APR and ADV collectors, and show a very good agreement with the numerical solutions. It was proven that the fitting of the current with the model functions gives a possibility to properly resolve even minor ion concentrations and to find the arrival angles of the ion flow in the multi-species plasma. The discussion is illustrated by an analysis of the instrument response in the ionospheric conditions which are predicted by the International Reference Ionosphere (IRI) model.Key words. Ionosphere (plasma convection; instruments and techniques) – Space plasma physics (experimental and mathematical techniques)

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de Planque, Maurits R. R. "Lipid bilayer platforms for parallel ion channel recordings". Japanese Journal of Applied Physics 61, SC (30 de março de 2022): SC0804. http://dx.doi.org/10.35848/1347-4065/ac4f7a.

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Abstract The ion flow through channel proteins embedded in a lipid bilayer membrane can be recorded as an electrical current, enabling biophysical characterization and pharmacological drug screening at a single-channel level. These measurements are challenging because the self-assembled bilayers are fragile and the currents are in the pA–nA range. This concise review introduces the bilayer recording methodology, with an emphasis on the requirements for full electrophysiology assays. The self-assembled lipid bilayer, formed in a ∼100 μm diameter aperture in between two aqueous chambers, is critical. Various approaches to increase the measurement throughput by scaling to aperture arrays are discussed in terms of current-amplifier technology, bilayer stability, ion channel incorporation, system functionality and obtained single-channel data. The various bilayer recording platforms all have advantages and limitations. Combining the strengths of the different platform architectures, for example, the use of shaped apertures, will be essential to realize and also automate parallel ion channel recordings.

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Harrison, Reid R., Ilya Kolb, Suhasa B. Kodandaramaiah, Alexander A. Chubykin, Aimei Yang, Mark F. Bear, Edward S. Boyden e Craig R. Forest. "Microchip amplifier for in vitro, in vivo, and automated whole cell patch-clamp recording". Journal of Neurophysiology 113, n.º 4 (15 de fevereiro de 2015): 1275–82. http://dx.doi.org/10.1152/jn.00629.2014.

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Patch clamping is a gold-standard electrophysiology technique that has the temporal resolution and signal-to-noise ratio capable of reporting single ion channel currents, as well as electrical activity of excitable single cells. Despite its usefulness and decades of development, the amplifiers required for patch clamping are expensive and bulky. This has limited the scalability and throughput of patch clamping for single-ion channel and single-cell analyses. In this work, we have developed a custom patch-clamp amplifier microchip that can be fabricated using standard commercial silicon processes capable of performing both voltage- and current-clamp measurements. A key innovation is the use of nonlinear feedback elements in the voltage-clamp amplifier circuit to convert measured currents into logarithmically encoded voltages, thereby eliminating the need for large high-valued resistors, a factor that has limited previous attempts at integration. Benchtop characterization of the chip shows low levels of current noise [1.1 pA root mean square (rms) over 5 kHz] during voltage-clamp measurements and low levels of voltage noise (8.2 μV rms over 10 kHz) during current-clamp measurements. We demonstrate the ability of the chip to perform both current- and voltage-clamp measurement in vitro in HEK293FT cells and cultured neurons. We also demonstrate its ability to perform in vivo recordings as part of a robotic patch-clamping system. The performance of the patch-clamp amplifier microchip compares favorably with much larger commercial instrumentation, enabling benchtop commoditization, miniaturization, and scalable patch-clamp instrumentation.

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Sobolewski, M. A. "Measuring the ion current in electrical discharges using radio-frequency current and voltage measurements". Applied Physics Letters 72, n.º 10 (9 de março de 1998): 1146–48. http://dx.doi.org/10.1063/1.121032.

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Kuuluvainen, H., J. Kannosto, A. Virtanen, J. M. Mäkelä, M. Kulmala, P. Aalto e J. Keskinen. "Measuring condensation sink and ion sink of atmospheric aerosols with the electrical low pressure impactor (ELPI)". Atmospheric Chemistry and Physics Discussions 9, n.º 4 (27 de julho de 2009): 15867–89. http://dx.doi.org/10.5194/acpd-9-15867-2009.

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Abstract. We investigate the suitability of ELPI for condensation sink and ion sink measurements. The aim is to find the simple calibration factors by which the measured ELPI currents can be converted to condensation or ion sinks. The calibration is based on DMPS and ELPI measurements within the period 15–25 May 2005 at a boreal forest site in Southern Finland. The values of condensation sink and ion sink were calculated from the DMPS size distributions using their theoretical definitions. After that the values were compared to theoretical and measured ELPI current, and calibration factors were specified. For condensation sink the calibration factor was found to be 7.27 E-06 s−1 fA−1 and for ion sink 7.33 E-06 s−1 fA−1. Simply by multiplying the total current of the outdoor ELPI by these factors, the values of condensation sink and ion sink can be measured.

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Lei, Chong, Michael F. Simpson e Anil V. Virkar. "Investigation of Ion and Electron Conduction in the Mixed Ionic-Electronic Conductor- La-Sr-Co-Fe-Oxide (LSCF) Using Alternating Current (AC) and Direct Current (DC) Techniques". Journal of The Electrochemical Society 169, n.º 1 (1 de janeiro de 2022): 014506. http://dx.doi.org/10.1149/1945-7111/ac43d8.

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Among many mixed ionic electronic conductors (MIECs), lanthanum strontium cobalt iron oxide (LSCF) has been proven as a promising material for use as cathode in SOFCs. The ion and electron conduction in LSCF need to be studied separately. To measure the ionic conductivity of LSCF, YSZ disks were applied to block the electronic current, and multilayered samples were made with YSZ disks in series with an LSCF disk. Both AC and DC techniques were used for the measurements. An LSCF(porous)/LSCF(dense)/LSCF(porous) bar-shaped sample was made to measure the electronic conductivity of LSCF. DC technique was utilized for the measurement. Results show that the ionic conductivity of LSCF is much lower than its electronic conductivity. The ionic conductivity of LSCF increases with increasing temperature (600 °C–900 °C), and the electronic conductivity decreases with increasing temperature (600 °C–900 °C). Measurements were also made on a foil of silver to investigate oxygen transport through it. From this, oxygen ion conductivity through silver was estimated.

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BADZIAK, J., S. GŁOWACZ, S. JABŁOŃSKI, P. PARYS, J. WOŁOWSKI e H. HORA. "Laser-driven generation of high-current ion beams using skin-layer ponderomotive acceleration". Laser and Particle Beams 23, n.º 4 (outubro de 2005): 401–9. http://dx.doi.org/10.1017/s0263034605050573.

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Basic properties of generation of high-current ion beams using the skin-layer ponderomotive acceleration (S-LPA) mechanism, induced by a short laser pulse interacting with a solid target are studied. Simplified scaling laws for the ion energies, the ion current densities, the ion beam intensities, and the efficiency of ions' production are derived for the cases of subrelativistic and relativistic laser-plasma interactions. The results of the time-of-flight measurements performed for both backward-accelerated ion beams from a massive target and forward-accelerated beams from a thin foil target irradiated by 1-ps laser pulse of intensity up to ∼ 1017 W/cm2 are presented. The ion current densities and the ion beam intensities at the source obtained from these measurements are compared to the ones achieved in recent short-pulse experiments using the target normal sheath acceleration (TNSA) mechanism at relativistic (>1019 W/cm2) laser intensities. The possibility of application of high-current ion beams produced by S-LPA at relativistic intensities for fast ignition of fusion target is considered. Using the derived scaling laws for the ion beam parameters, the achievement conditions for ignition of compressed DT fuel with ion beams driven by ps laser pulses of total energy ≤ 100 kJ is shown.

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Bradley, M. P., e C. J. T. Steenkamp. "Time-Resolved Ion and Electron Current Measurements in Pulsed Plasma Sheaths". IEEE Transactions on Plasma Science 34, n.º 4 (agosto de 2006): 1156–59. http://dx.doi.org/10.1109/tps.2006.877744.

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Osswald, P. J., S. V. Erhard, A. Noel, P. Keil, F. M. Kindermann, H. Hoster e A. Jossen. "Current density distribution in cylindrical Li-Ion cells during impedance measurements". Journal of Power Sources 314 (maio de 2016): 93–101. http://dx.doi.org/10.1016/j.jpowsour.2016.02.070.

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Tolstoguzov, A. B., U. Bardi e S. P. Chenakin. "Depth profiling using secondary ion mass spectrometry and sample current measurements". Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques 1, n.º 6 (dezembro de 2007): 734–40. http://dx.doi.org/10.1134/s1027451007060195.

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Harrison, R. G. "A noise-rejecting current amplifier for surface atmospheric ion flux measurements". Review of Scientific Instruments 68, n.º 9 (setembro de 1997): 3563–65. http://dx.doi.org/10.1063/1.1148323.

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Xu, Yida, Wittaya Ngeontae, Ernö Pretsch e Eric Bakker. "Backside Calibration Chronopotentiometry: Using Current to Perform Ion Measurements by Zeroing the Transmembrane Ion Flux". Analytical Chemistry 80, n.º 19 (outubro de 2008): 7516–23. http://dx.doi.org/10.1021/ac800774e.

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Zanáška, Michal, Daniel Lundin, Nils Brenning, Hao Du, Pavel Dvořák, Petr Vašina e Ulf Helmersson. "Dynamics of bipolar HiPIMS discharges by plasma potential probe measurements". Plasma Sources Science and Technology 31, n.º 2 (1 de fevereiro de 2022): 025007. http://dx.doi.org/10.1088/1361-6595/ac4b65.

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Abstract The plasma potential at a typical substrate position is studied during the positive pulse of a bipolar high-power impulse magnetron sputtering (bipolar HiPIMS) discharge with a Cu target. The goal of the study is to identify suitable conditions for achieving ion acceleration independent on substrate grounding. We find that the time-evolution of the plasma potential during the positive pulse can be separated into several distinct phases, which are highly dependent on the discharge conditions. This includes exploring the influence of the working gas pressure (0.3–2 Pa), HiPIMS peak current (10–70 A corresponding to 0.5–3.5 A cm−2), HiPIMS pulse length (5–60 μs) and the amplitude of the positive voltage U + applied during the positive pulse (0–150 V). At low enough pressure, high enough HiPIMS peak current and long enough HiPIMS pulse length, the plasma potential at a typical substrate position is seen to be close to 0 V for a certain time interval (denoted phase B) during the positive pulse. At the same time, spatial mapping of the plasma potential inside the magnetic trap region revealed an elevated value of the plasma potential during phase B. These two plasma potential characteristics are identified as suitable for achieving ion acceleration in the target region. Moreover, by investigating the target current and ion saturation current at the chamber walls, we describe a simple theory linking the value of the plasma potential profile to the ratio of the available target electron current and ion saturation current at the wall.

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Sobolewski, Mark A. "Measuring the ion current in high-density plasmas using radio-frequency current and voltage measurements". Journal of Applied Physics 90, n.º 6 (15 de setembro de 2001): 2660–71. http://dx.doi.org/10.1063/1.1390491.

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Sikora, Jarosław, Bartosz Kania e Janusz Mroczka. "Thermionic Electron Beam Current and Accelerating Voltage Controller for Gas Ion Sources". Sensors 21, n.º 8 (20 de abril de 2021): 2878. http://dx.doi.org/10.3390/s21082878.

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Thermionic emission sources are key components of electron impact gas ion sources used in measuring instruments, such as mass spectrometers, ionization gauges, and apparatus for ionization cross-section measurements. The repeatability of the measurements taken with such instruments depends on the stability of the ion current, which is a function, among other things, of the electron beam current and electron accelerating voltage. In this paper, a laboratory thermionic electron beam current and accelerating voltage controller is presented, based on digital algorithm implementation. The average value of the percentage standard deviation of the emission current is 0.021%, and the maximum electron accelerating voltage change versus the emission current is smaller than 0.011% in the full operating range of the emission current. Its application as a trap current or emission current-regulated ion source power supply could be useful in many measuring instruments, such as in microelectromechanical system (MEMS) mass spectrometers as universal gas sensors, where a stable emission current and electron energy are needed.

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Artemyev, A. V., A. A. Petrukovich, L. M. Zelenyi, H. V. Malova, V. Y. Popov, R. Nakamura, A. Runov e S. Apatenkov. "Comparison of multi-point measurements of current sheet structure and analytical models". Annales Geophysicae 26, n.º 9 (15 de setembro de 2008): 2749–58. http://dx.doi.org/10.5194/angeo-26-2749-2008.

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Abstract. Current density profiles of 22 thin current sheets, crossed by four Cluster spacecraft in the magnetotail are compared with the self-consistent model of anisotropic 1-D equilibrium, including several species of quasi-adiabatic (transient) ions and drifting electrons. In order to examine ion-scale features of the current density profile Cluster data from the 2001 and 2004 tail seasons were used when the spacecraft separation was about 2000 and 1000 km, respectively, while electron-scale features are studied using Cluster data from the 2003 season , when the spacecraft separation was about 200 km. The model ion and electron current density peaks embedded in a background plasma sheet successfully reproduce observed profiles. Stability criteria of the model current sheet are also consistent with the experiment.

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Østedgaard-Munck, David Nicolas, Jacopo Catalano e Anders Bentien. "Direct Measurements of Electroviscous Phenomena in Nafion Membranes". Membranes 10, n.º 11 (25 de outubro de 2020): 304. http://dx.doi.org/10.3390/membranes10110304.

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Investigation of electroviscous effects is of interest to technologies that exploit transport of ions through ion exchange membranes, charged capillaries, and porous media. When ions move through such media due to a hydrostatic pressure difference, they interact with the fixed charges, leading to an increased hydraulic resistance. Experimentally this is observed as an apparent increase in the viscosity of the solution. Electroviscous effects are present in all electrochemical membrane-based processes ranging from nanofiltration to fuel-cells and redox flow batteries. Direct measurements of electroviscous effects varying the applied ionic current through Nafion membranes have, to the best of the authors’ knowledge, not yet been reported in literature. In the current study, electroviscous phenomena in different Nafion ion exchange membranes are measured directly with a method where the volume permeation is measured under constant trans-membrane pressure difference while varying the ion current density in the membrane. The direct measurement of the electroviscous effect is compared to the one calculated from the phenomenological transport equations and measured transport coefficients. Within the experimental uncertainty, there is a good agreement between the two values for all membranes tested. We report here an electroviscous effect for all Nafion membranes tested to be κH?κH−1=1.15−0.052+0.035.

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Pastor, D., J. Olea, A. del Prado, E. García-Hemme, R. García-Hernansanz, L. González-Pariente, I. Mártil e G. González-Díaz. "Study of the electrical behavior in Intermediate Band-Si junctions". MRS Proceedings 1493 (2013): 85–90. http://dx.doi.org/10.1557/opl.2013.224.

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ABSTRACTIn this study we analyze the electrical behavior of a junction formed by an ultraheavily Ti implanted Si layer processed by a Pulsed Laser Melting (PLM) and the non implanted Si substrate. This electrical behavior exhibits an electrical decoupling effect in this bilayer that we have associated to an Intermediate Band (IB) formation in the Ti supersaturated Si layer. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) measurements show a Ti depth profile with concentrations well above the theoretical limit required to the IB formation. Sheet resistance and Hall mobility measurements in the van der Pauw configuration of these bilayers exhibit a clear dependence with the different measurement currents introduced (1µA-1mA). We find that the electrical transport properties measured present an electrical decoupling effect in the bilayer as function of the temperature. The dependence of this effect with the injected current could be explained in terms of an additional current flow in the junction from the substrate to the IB layer and in terms of the voltage dependence in the junction with the measurement current.

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Kuuluvainen, H., J. Kannosto, A. Virtanen, J. M. Mäkelä, M. Kulmala, P. Aalto e J. Keskinen. "Technical Note: Measuring condensation sink and ion sink of atmospheric aerosols with the electrical low pressure impactor (ELPI)". Atmospheric Chemistry and Physics 10, n.º 3 (5 de fevereiro de 2010): 1361–68. http://dx.doi.org/10.5194/acp-10-1361-2010.

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Abstract. We investigate the suitability of ELPI for condensation sink and ion sink measurements. The aim is to find the simple calibration factors by which the measured ELPI current can be converted to condensation or ion sinks. The calibration is based on DMPS and ELPI measurements within the period 15–25 May 2005 at a boreal forest site in Southern Finland. The values of condensation sink and ion sink were calculated from the DMPS size distributions using their theoretical definitions. After that the values were compared to theoretical and measured ELPI current, and calibration factors were specified. For condensation sink the calibration factor was found to be 7.27E-06 s−1 fA−1 and for ion sink 8.55E-06 s−1 fA−1. Simply by multiplying the total current of the outdoor ELPI by these factors, the values of condensation sink and ion sink can be measured.

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Hirata, M., Y. Miyake, T. Cho, J. Kohagura, T. Numakura, K. Shimizu, M. Ito et al. "Simultaneous measurements of ion and electron currents using a novel compact electrostatic end-loss-current detector". Review of Scientific Instruments 77, n.º 10 (outubro de 2006): 10E719. http://dx.doi.org/10.1063/1.2338304.

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Zhang, Haowei, Lili Sun, Chengli Song, Ying Liu, Xueting Xuan, Fei Wang, Jing Zhong e Li Sun. "Integrated solid-state wearable sweat sensor system for sodium and potassium ion concentration detection". Sensor Review 42, n.º 1 (13 de janeiro de 2022): 76–88. http://dx.doi.org/10.1108/sr-03-2021-0081.

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Purpose Design, fabricate and evaluate all-solid-state wearable sensor systems that can monitor ion concentrations in human sweat to provide real time health analysis and disease diagnosis capabilities. Design/methodology/approach A human health monitoring system includes disposable customized flexible electrode array and a compact signal transmission-processing electronic unit. Findings Patterned rGO (reduced-graphene oxide) layers can replace traditional metal electrodes for the fabrication of free-standing all solid film sensors to provide improved flexibility, sensitivity, selectivity, and stability in ion concentration monitoring. Electrochemical measurements show the open circuit potential of current selective electrodes exhibit near Nernst responses versus Na+ and K+ ion concentration in sweat. These signals show great stability during a typical measurement period of 3 weeks. Sensor performances evaluated through real time measurements on human subjects show strong correlations between subject activity and sweating levels, confirming high degree of robustness, sensitivity, reliability and practicality of current sensor systems. Originality/value In improving flexibility, stability and interfacial coherency of chemical sensor arrays, rGO films have been the developed as a high-performance alternative to conventional electrode with significant cost and processing complexity reduction. rGO supported solid state electrode arrays have been found to have linear potential response versus ion concentration, suitable for electrochemical sensing applications. Current sweat sensor system has a high degree of integration, including electrode arrays, signal processing circuits, and data visualization interfaces.

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Walker, Mitchell L. R., Allen L. Victor, Richard R. Hofer e Alec D. Gallimore. "Effect of Backpressure on Ion Current Density Measurements in Hall Thruster Plumes". Journal of Propulsion and Power 21, n.º 3 (maio de 2005): 408–15. http://dx.doi.org/10.2514/1.7713.

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Cesca, Tiziana, Andrea Gasparotto e Beatrice Fraboni. "Electrical spectroscopy of high resistivity ion-implanted layers by current-voltage measurements". Applied Physics Letters 93, n.º 10 (8 de setembro de 2008): 102114. http://dx.doi.org/10.1063/1.2975372.

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Hayakawa, Yukio. "Measurements of Current Distribution on a Two-Grid-Ion-Extraction-System Gridlet". Journal of Propulsion and Power 23, n.º 6 (novembro de 2007): 1279–84. http://dx.doi.org/10.2514/1.28432.

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De Vleeschouwer, Herbert, Stefaan Vermael, Fatiha Bougrioua, Arthur Adamski, Goran Stojmenovic, Kristiaan Neyts, Herman Pauwels, Alwin Verschueren, Rob Van Asselt e Els Alexander. "10.4: Ion Transport Simulations and DC Leakage Current Measurements in Nematic LCDs". SID Symposium Digest of Technical Papers 32, n.º 1 (2001): 128. http://dx.doi.org/10.1889/1.1831797.

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Woryna, E., P. Parys, J. Wol/owski, J. Krása, L. Láska, K. Rohlena, M. P. Stockli, S. Winecki e B. Walch. "Absolute measurements of characteristics of tantalum ion current from laser-produced plasma". Review of Scientific Instruments 69, n.º 2 (fevereiro de 1998): 1045–47. http://dx.doi.org/10.1063/1.1148548.

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Gangotra, Ankita, e Geoff R. Willmott. "Mechanical properties of bovine erythrocytes derived from ion current measurements using micropipettes". Bioelectrochemistry 128 (agosto de 2019): 204–10. http://dx.doi.org/10.1016/j.bioelechem.2019.04.013.

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Wang, P., L. Yang, H. Wang, D. M. Tartakovsky e S. Onori. "Temperature estimation from current and voltage measurements in lithium-ion battery systems". Journal of Energy Storage 34 (fevereiro de 2021): 102133. http://dx.doi.org/10.1016/j.est.2020.102133.

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BADZIAK, J., S. GŁOWACZ, S. JABŁOŃSKI, P. PARYS, J. WOŁOWSKI e H. HORA. "Generation of picosecond high-density ion fluxes by skin-layer laser-plasma interaction". Laser and Particle Beams 23, n.º 2 (junho de 2005): 143–47. http://dx.doi.org/10.1017/s0263034605050238.

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The possibilities of producing ultrahigh-current-density ps ion fluxes by the skin-layer interaction of a short (≤ 1ps) laser pulse with plasma were studied using two-fluid hydrodynamic simulations, and the time-of-flight measurements. Backward-emitted ion fluxes from a massive (Au) target as well as forward-emitted fluxes from various thin foil targets irradiated by a 1-ps laser pulse of intensity up to 2 × 1017W/cm2were recorded. Both the simulations and the measurements confirmed that using the short-pulse skin-layer interaction of a laser pulse with a thin pre-plasma layer in front of a solid target, a high-density collimated ion flux of extremely high ion current density (∼ 1010A/cm2close to the target), can be generated at laser intensity only ∼ 1017W/cm2. The ion current densities produced by this way were found to be comparable to (or even higher than) those estimated from recent short-pulse experiments using a target normal sheath acceleration mechanism at relativistic laser intensities. The effect of the target structure on the current densities and energies of forward-emitted ions is demonstrated.

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Cipciar, D., J. Adamek, J. Horacek, J. Cavalier e M. Hron. "Statistical properties of ion and electron temperature fluctuations in the edge of the COMPASS tokamak". Plasma Physics and Controlled Fusion 64, n.º 5 (13 de abril de 2022): 055021. http://dx.doi.org/10.1088/1361-6587/ac5a0b.

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Abstract This paper presents measurements of the plasma turbulence with an emphasis on the ion temperature fluctuations in comparison to the electron temperature and the ion saturation current fluctuations in the edge of the COMPASS tokamak. The ion temperature values are obtained by using a fast swept ball-pen probe, with temporal resolution up to 10 µs, accompanied by independent 1 µs measurements of the electron temperature and ion saturation current. The experimental results obtained for a wide range of line-averaged densities show that statistical properties of the fluctuations are in good agreement with a form of beta or gamma distribution function. In addition, the dependence of the averaged ion and electron temperatures on the line-averaged density is studied in the near and main scrape off layer region.

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