Artículos de revistas: ""wall-Tube" electrode"

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CHENG, Lingyun, Nianwen XIANG, Kejie LI, Weijiang CHEN, Kai BIAN, Jin YANG, Zongqi XU, Congying HAN, Hongyang GU y Chun YANG. "Reliability improvement of gas discharge tube by suppressing the formation of short-circuit pathways". Plasma Science and Technology 24, n.º 3 (1 de marzo de 2022): 035501. http://dx.doi.org/10.1088/2058-6272/ac479c.

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Abstract After cumulative discharge of gas discharge tube (GDT), it is easy to form a short circuit pathway between the two electrodes, which increases the failure risk and causes severe influences on the protected object. To reduce the failure risk of GDT and improve cumulative discharge times before failure, this work aims to suppress the formation of two short-circuit pathways by optimizing the tube wall structure, the electrode materials and the electrode structure. A total of five improved GDT samples are designed by focusing on the insulation resistance change that occurs after the improvement; then, by combining these designs with the microscopic morphology changes inside the cavity and the differences in deposition composition, the reasons for the differences in the GDT failure risk are also analyzed. The experimental results show that compared with GDT of traditional structure and material, the method of adding grooves at both ends of the tube wall can effectively block the deposition pathway of the tube wall, and the cumulative discharge time before device failure is increased by 149%. On this basis, when the iron-nickel electrode is replaced with a tungsten-copper electrode, the difference in the electrode’s surface splash characteristics further extends the discharge time before failure by 183%. In addition, when compared with the traditional electrode structure, the method of adding an annular structure at the electrode edge to block the splashing pathway for the particles on the electrode surface shows no positive effect, and the cumulative discharge time before the failure of the two structures is reduced by 22.8% and 49.7%, respectively. Among these improved structures, the samples with grooves at both ends of the tube wall and tungsten-copper as their electrode material have the lowest failure risk.

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2

DEHGHANI, SAJJAD, MOHAMMAD KAZEM MORAVVEJ-FARSHI y MOHAMMAD HOSSEIN SHEIKHI. "TEMPERATURE DEPENDENCE OF ELECTRICAL RESISTANCE OF INDIVIDUAL CARBON NANOTUBES AND CARBON NANOTUBES NETWORK". Modern Physics Letters B 26, n.º 21 (16 de julio de 2012): 1250136. http://dx.doi.org/10.1142/s0217984912501369.

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We present a model to understand the effect of temperature on the electrical resistance of individual semiconducting single wall carbon nanotubes (s-SWCNTs) of various diameters under various electric fields. The temperature dependence of the resistance of s-SWCNTs and metallic SWCNTs (m-SWCNTs) are compared. These results help us to understand the temperature dependence of the resistance of SWCNTs network. We experimentally examine the temperature dependence of the resistance of random networks of SWCNTs, prepared by dispersing CNTs in ethanol and drop-casting the solution on prefabricated metallic electrodes. Examining various samples with different electrode materials and spacings, we find that the dominant resistance in determination of the temperature dependence of resistance of the network is the resistance of individual tubes, rather than the tube–tube resistance or tube–metal contact resistance. It is also found that the tube–tube resistance depends on the electrode spacing and it is more important for larger electrode spacings. By applying high electric field to burn the all-metallic paths of the SWCNTs network, the temperature dependence of the resistance of s-SWCNTs is also examined. We also investigate the effect of acid treatment of CNTs on the temperature dependence of the resistance of SWCNTs and also multi-wall CNTs (MWCNTs) networks.

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3

Stein, Jennifer A. y Alanah Fitch. "Dual wall-tube electrode cell for use in clay-modified electrode studies". Electroanalysis 6, n.º 1 (enero de 1994): 23–28. http://dx.doi.org/10.1002/elan.1140060106.

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4

Birhane, Y. T., S. C. Lin y F. C. Lai. "Effect of Electrode Length on the Performance of EHD Gas Pump". Applied Mechanics and Materials 598 (julio de 2014): 355–60. http://dx.doi.org/10.4028/www.scientific.net/amm.598.355.

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The effects of electrode length on the characteristics of flow induced by an electrohydrodynamic (EHD) gas pump in circular pipe have been experimentally examined in this study. The gas pump has a diameter of 61.8 mm and uses eight evenly spaced emitting electrodes which are flush mounted on the tube inner wall. The gap distance between emitting and ground electrodes is fixed at 25 mm and two emitting electrode lengths (15 mm and 40 mm) are considered. Experiments are conducted using positive corona discharge with voltage varying from 17.5 kV to 23 kV. Several important implications from the present results for practical engineering applications are presented.

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5

Li, Mao Dong, Xue Ying Tang, Yu Hui Du, Juan Liu, Jun Ming Zhao y Zhi Ping Zhu. "Electrochemical Property Study of Water-Wall Tube 20G in SO₄^2- Medium at Room Temperature". Advanced Materials Research 676 (marzo de 2013): 31–34. http://dx.doi.org/10.4028/www.scientific.net/amr.676.31.

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In the article, the effect of SO42-on the corrosion behavior of boiler water-wall material 20G under the equilibrium phosphate treatment (EPT) was studied by a series of electrochemical experiments at room temperature. Electrodes AC impedance value (Rp) was used to evaluate the corrosion resistance of the material. The experiment results show that, SO42-ion is aggressive anion; water-wall tube material 20G has certain sensitive corrosion to the SO42-. The 20G electrode AC impedance value decreases with the increase of the SO42-’s concentration and the material corrosion resistance reduces.

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6

Yao, Fu, Duan Xiao-Long, Xing Ming-Ming, Luo Xi-Xian, Zhang Ying-Hui y Liu Wang. "Study on Fabrication and UV Photoelectric Property of TiO2 Nanotube Array Electrodes". Journal of Nanoscience and Nanotechnology 16, n.º 4 (1 de abril de 2016): 3945–50. http://dx.doi.org/10.1166/jnn.2016.11830.

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Highly ordered TiO2 nanotube array electrodes were successfully fabricated by a two-step anodization method on Ti sheet substrates in an electrolyte composed of ammonium fluoride, deionized water, and glycol. The tube wall was smooth, and the average internal and external diameters, wall thickness, and tube length achieved were 80 nm, 90 nm, 10 nm, and 9 μm, respectively. X-ray diffraction and field emission scanning electron microscopy results revealed that the TiO2 nanotube arrays presented an amorphous structure. When calcined at 300 °C, the arrays crystallized into the anatase phase, and the crystallization degree of the oxide layer increased as the temperature rose. Calcinating at 400 °C did not obviously disrupt the porous structure of the highly ordered arrays. However, higher temperature enlarged the diameter of the nanotube array and roughened the tube wall. When the temperature reached 600 °C, the nanotube mouth broke because of the excessive stress, causing the oxide layer’s thinness and nanotube mouth clogging. The photoelectric test showed that the electrode presented obvious photoresponse under 300–400 nm UV excitation (maximized at 360 nm). The degree of crystallization and the micro-structure of the oxide layer can significantly affect the photoelectric properties of the electrode. After calcination at 400 °C, the TiO2 nanotube arrays, with highly ordered tubular structure directly connected to the Ti substrate, can ensure the rapid transportation of photo-induced electrons to the Ti substrate, while the high crystallinity of the arrays can help reduce the defect density of the nanotube and extend the lifetime of the photo-induced carriers. The electrode showed the best photoelectric property, and the photocurrent intensity was maximized (29.6 μA). However, the calcination process with over-temperature resulted in substantial loss of the TiO2 oxide layer, mouth clogging, and a severe decline in the photoelectric properties.

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7

Kapauan, Amando F. "A wall-tube electrode cell for computerized potentiometric stripping analysis". Analytical Chemistry 60, n.º 19 (octubre de 1988): 2161–62. http://dx.doi.org/10.1021/ac00170a037.

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8

YABUTANI, TOMOKI, YOSHIO SHODA, YUJI TANI, YOHEI YAMADA y JUNKO MOTONAKA. "DIRECT OXIDATION OF TRYPTOPHAN ON MULTI-WALL CARBON NANOTUBES MODIFIED CARBON ELECTRODE AND ITS APPLICATION TO FUEL CELL". International Journal of Modern Physics: Conference Series 06 (enero de 2012): 115–20. http://dx.doi.org/10.1142/s2010194512003030.

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Direct oxidation of tryptophan on multi-wall carbon nanotubes modified glassy carbon electrode was examined. Surface poisoning, which was suppression of oxidative current caused from adsorption of oxidized compounds of amino acids through multiple redox scan, was observed on carbon material electrodes (multi-wall carbon nano tube(CNT), carbon powder(CP), Ketjen Black (KB) and glassy carbon(GC). It was found that CNT showed a highly inhibitory effect on the surface poisoning and high current value in the direct oxidation of tryptophan because of a π-π interaction between CNT and indole ring of tryptophan results from orbital mixing. This CNT modified GC electrode was applied to an anode in a fuel cell used with amino acids as fuel. As a result, the maximum of the power density showed 0.36 mW cm-2 at 2.5 mA cm-2 of the current density and 140 mV of the cell voltage.

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9

Rees, Neil V., Oleksiy V. Klymenko, Barry A. Coles y Richard G. Compton. "Fast scan linear sweep voltammetry at a high-speed wall-tube electrode". Journal of Electroanalytical Chemistry 557 (octubre de 2003): 99–107. http://dx.doi.org/10.1016/s0022-0728(03)00352-8.

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10

Gao, Jun, Hao Chen, Tianlong Li, Xin Qiao, Xinai Guo y Shida Shi. "Leakage of water-cooled wall tube in subcritical boiler". Journal of Physics: Conference Series 2760, n.º 1 (1 de mayo de 2024): 012052. http://dx.doi.org/10.1088/1742-6596/2760/1/012052.

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Abstract Usually, heating surfaces used in thermal power plant boilers include economizers, water-cooled walls, superheaters, and reheaters, abbreviated as the “four tubes” of boilers. The leakage of the heating surface is a common form of unplanned shutdown in thermal power plants, accounting for more than 50% of abnormal shutdown accidents of units. Once the heating surface explosion occurs, the thermal power plant needs to shut down for treatment, resulting in huge losses in power generation and fuel consumption during startup and shutdown. This has a huge impact on the safety production and economic benefits of the enterprise. In this paper, the leaked water-cooled wall tube in the subcritical boiler was studied by means of microstructure analysis, hardness test, energy spectrum analysis, chemical composition test, macro-morphology inspection, and tensile test. The results revealed that the oxygen concentration difference between the area installed in ceiling pouring material and the area exposed to the air can result in significant differences in electrode potential between different areas of the front water wall tube passing through the ceiling. An oxygen concentration difference battery is formed. In this way, the water-cooled wall steel pipe continuously corroded and thinned. Finally, perforation leakage occurred under the pressure of the internal high-temperature medium.

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11

Fan, Yubin, Xuefeng Xu, Ruichen Tao, Ming Luo, Xiaodong Li, Liming Wei, Shitian Wu, Jie Xiao y Xiang Zeng. "Experimental Investigation of Current Intensity and Feed Speed in Electrically Assisted Necking and Thickening of 5A02 Aluminum Alloy Tubes". Materials 17, n.º 4 (6 de febrero de 2024): 771. http://dx.doi.org/10.3390/ma17040771.

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In order to further explore the forming limits of thin-wall tube necking and thickening, and obtain sufficient thickness of the tube in the thickening area, local electric pulse-assisted forming experiments were carried out to study the effects of current intensity and feed speed on the necking and thickening forming of thin-wall tube. The experimental results show that with the increase in current intensity, the temperature in the forming area of the tube increases, and the forming load for necking and thickening decreases. However, with the increase in feed speed, the overall forming load for necking and thickening increases in general, and the smaller feed speed is more conducive to forming. Taking into account the forming efficiency and electrode loss, the corresponding forming process window is obtained for the manufacturing of good parts. That is, during the necking stage, the current intensity shall not be less than 300 A, and the feed speed shall not exceed 10 mm/min. During the thickening stage, the current intensity should not be less than 1400 A, and the feed speed should not exceed 1 mm/min. The target part is finally formed, with an average wall thickness of 5.984 mm in the thickening zone and a thickening rate of 303.2%.

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12

Ghimire, Bhagirath, Bethany L. Patenall, Endre J. Szili, Nishtha Gaur, Pradeep Lamichhane, Naing T. Thet, Dhruv Trivedi, Andrew Toby A. Jenkins y Robert D. Short. "The influence of a second ground electrode on hydrogen peroxide production from an atmospheric pressure argon plasma jet and correlation to antibacterial efficacy and mammalian cell cytotoxicity". Journal of Physics D: Applied Physics 55, n.º 12 (28 de diciembre de 2021): 125207. http://dx.doi.org/10.1088/1361-6463/ac43d9.

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Abstract This study investigates how addition of a 2nd ground electrode in an argon plasma jet influences the production of hydrogen peroxide (H2O2) in deionised water (DIW). Briefly, plasma is ignited by purging argon gas through a quartz tube at 1 l min−1 and applying a sinusoidal voltage of 7 kV (peak–peak) at 23.5 kHz to a high voltage stainless steel needle electrode sealed inside the quartz tube surrounded by one or two copper ring(s) that served as the ground electrode(s) situated downstream of the high voltage electrode. The mechanisms of H2O2 production are investigated through the electrical and optical plasma properties and chemical analysis of the treated DIW. We discover that the addition of a 2nd ground electrode results in higher accumulation of charges on the inner wall surface of the quartz tube of the plasma jet assembly resulting in an increase in the discharge current and dissipated power. This further leads to an increase in the electron temperature that more than doubles the H2O2 production through dissociative recombination of water vapour molecules, whilst still maintaining a biological tissue tolerable gas temperature. The double ground electrode plasma jet is shown to be highly effective at reducing the growth of common wound pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) in both planktonic and biofilm states whilst inducing a low level of cytotoxicity in HaCaT keratinocyte skin-like cells under certain conditions. The information provided in this study is useful in understanding the complex physicochemical processes that influence H2O2 production in plasma jets, which is needed to optimise the development of plasma sources for clinical applications.

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13

Mogi, Iwao, Ryoichi Morimoto, Ryoichi Aogaki y Kohki Takahashi. "Effects of Vertical Magnetohydrodynamic Flows on Chiral Surface Formation in Magnetoelectrolysis". Magnetochemistry 4, n.º 3 (6 de septiembre de 2018): 40. http://dx.doi.org/10.3390/magnetochemistry4030040.

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Magnetoelectrolysis (electrolysis in magnetic fields) has potential to produce chiral surfaces on metal films. The Lorentz force causes two types of magnetohydrodynamic (MHD) flows; a vertical MHD flow and micro-MHD vortices, and the combination of these MHD flows has been considered to produce chiral surfaces. This paper shows the effects of vertical MHD flow on the chiral surface formation in magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) of copper films. To control the vertical MHD flows the working electrode was embedded in a tube wall with various heights of 2–12 mm, and the vertical MHD flows were expected to penetrate into the tubes with damping. In both MED and MEE experiments, the surface chirality diminished considerably at the wall height of 12 mm. When the penetrating MHD flow could not reach the electrode surface in the sufficiently tall wall, such an MHD flow could not affect the micro-MHD vortices. These results demonstrate that the vertical MHD flow plays a significant role in symmetry breaking of micro-MHD vortices.

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14

Akishev, Yuri, Tatyana Alekseeva, Vladimir Karalnik y Alexander Petryakov. "On the slow ionization waves forming the breakdown in a long capillary tube with helium at low pressure". Journal of Physics D: Applied Physics 55, n.º 14 (4 de enero de 2022): 145202. http://dx.doi.org/10.1088/1361-6463/ac45af.

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Abstract The results of studies of an electrical breakdown leading to the glow discharge ignition in a long capillary quartz tube are presented. Under such conditions, the breakdown completion is preceded by the development of direct, backward, and counter slow ionization waves (IWs) traveling in the tube. The initiation of the waves was created in helium at low pressure (P = 10 Torr) by the high-voltage pulses of positive and negative polarity with amplitude of several kilovolts. In the beginning, the regime without the breakdown completion in the tube was studied. In this regime, the propagation of only direct positive and direct negative IWs happens. The research on dynamics of the direct, backward, and counter positive and negative waves followed by a complete breakdown was done as well. The influence of the pre-existing plasma on the IWs propagation was also studied. The plasma was created in advance by low-current glow discharge being formed in the tube. The instant images of IWs were correlated with the electrical currents formed by the waves, that is, with the displacement current through the dielectric wall and the conductive current through the plasma column. In the experiments, the fine-sectioned electrode wrapped around the lateral tube surface was used. The usage of such electrode allowed one to study the dynamics of the surface charge deposition and deletion happening during the direct and backward wave propagation, respectively. Finally, a strong difference in the spatial structure and velocity of positive and negative direct waves traveling through non-ionized gas was revealed. Contrary, both the positive and negative backward waves traveling through the plasma formed by previous direct waves have the parameters close to each other.

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15

Zhu, Yan-Rong y Zheng-Shi Chang. "Effects of pulse voltage rising edge on discharge evolution of He atmospheric pressure plasma jet in dielectric tube". Acta Physica Sinica 71, n.º 2 (2022): 025202. http://dx.doi.org/10.7498/aps.71.20210470.

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In this work, we employ pulse voltage to drive an atmospheric pressure plasma jet (APPJ) in Helium, and consider mainly the evolution of discharge inside tube. Specifically, the effects of rising edge on the discharge evolution are studied through the simulation and experiment. The spatiotemporal evolution of electron density, ionization source, electron temperature and excited helium atom are evaluated. Besides, the mechanism affecting the rise time is analyzed by the parameters such as discharge current, sheath thickness and surface charge density distribution. In the considered cases, the ionization wave propagates to the ground electrode and downstream of the active electrode in the dielectric tube. The plasma with faster rising edge has larger electron temperature, discharge current, electron density and electric field strength. With the change of voltage rising edge, there occur two discharge modes: hollow mode and solid mode in dielectric barrier discharge (DBD) area. When the rising edge is of nanosecond and sub microsecond, it develops into hollow mode, and changes into solid mode after the rising edge has continued to increase. Both discharge modes are essentially affected by the sheath thickness, the electric field distribution, and the surface charge density inside the tube. When the sheath thickness is less than 1.8 mm, the plasma usually propagates in hollow mode, and when the sheath thickness is equal to 1.8 mm, the radial propagation range of the plasma is limited and changes into solid propagation. In the DBD region, when the electric field is mainly axial component, the plasma propagates in the mode at the beginning of discharge; inside the ground electrode, owing to the fact that the applied electric field is deviated from the radial direction, and that the positive charge deposited on the tube wall forms a radial self-built electric field, the strong radial electric field formed by the superposition of the two fields causes the discharge to propagate in hollow mode.

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16

Wang, Zhengguo y Chunya Li. "Electrochemical investigation of hymecromone at a multi-wall carbon nano-tube/cetyl pyridine bromine composite film electrode". Russian Journal of Electrochemistry 43, n.º 12 (diciembre de 2007): 1364–68. http://dx.doi.org/10.1134/s1023193507120051.

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17

Lee, Ha Na, Jae Yeong Jeong y Yong Bae Ji. "Retrosternal goiter presenting airway obstruction: A case report". Korean Intraoperative Neuromonitoring Society 3, n.º 1 (31 de mayo de 2023): 45–49. http://dx.doi.org/10.54441/jnn.2023.3.1.45.

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Open surgical treatment is the traditional approach and management of retrosternal goiter presenting airway obstruction. Tracheal repair is primarily considered in cases of significant airway narrowing. An 88-year-old female presented with worsening dyspnea and was diagnosed with a huge retrosternal goiter. Preoperative imaging revealed airway compression, and thus a thyroidectomy with possible tracheal repair was planned. However, conventional electromyography tube cannot be used due to narrow airway. We performed intraoperative neural monitoring successfully with needle electrode. Tracheal repair was not necessary after removal of the goiter because tracheal wall recovered from compression by thyroid gland. Here we report this case with a review of literature.

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18

Klymenko, Oleksiy V., David J. Gavaghan, Kathryn E. Harriman y Richard G. Compton. "Finite element simulation of electrochemically reversible, quasi-reversible and irreversible linear sweep voltammetry at the wall tube electrode". Journal of Electroanalytical Chemistry 531, n.º 1 (agosto de 2002): 25–31. http://dx.doi.org/10.1016/s0022-0728(02)01017-3.

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19

Xie, Yi Bing. "Preparation and Electrochemical Properties of Flow-Through TiO₂ Nanoarray". Journal of Nano Research 65 (diciembre de 2020): 1–12. http://dx.doi.org/10.4028/www.scientific.net/jnanor.65.1.

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Microstructure-tailored TiO2 nanoarrays with adjustive wall-hole morphology have been designed to improve electrochemical properties. Tubular, porous and flow-through TiO2 nanoarrays are fabricated by one-stepped, two-stepped and three-stepped anodization process under the controlled reaction condition. Tubular nanoarray with the opened-mouth and closed-bottom has a tube diameter of 120-130nm, a length of 8.12μm, and wall thickness of 15nm. Similarly, porous TiO2 nanoarray with the opened-mouth and closed-bottom has a pore diameter of 60-70nm, a length of 8.25μm, neighboring wall distance of 70-80nm. Comparatively, flow-through TiO2 nanoarray with the opened-mouth and opened-bottom has a pore diameter of 110-120nm, a length of 8.56μm, neighboring wall distance of 40nm. In comparison with tubular and porous TiO2 nanoarrays, flow-through TiO2 nanoarray indicates the deceased charge transfer resistance and diffusion-related Warburg impedance, presenting the enhanced current response at the same electrode potential. Accordingly, bottom-opened flow-through TiO2 nanoarray achieves the specific capacitance of 6.35 mF cm-2, which is higher than the bottom-closed tubular and porous TiO2 nanoarrays (2.94 and 3.78 mF cm-2). The flow-through TiO2 nanoarray presents the improved electrochemical performance for the electrochemical energy-storage.

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Gottwald, Martin y Gerhard von der Emde. "Bio-Inspired Active Electrolocation Sensors for Inspection of Tube Systems". Advances in Science and Technology 84 (septiembre de 2012): 45–50. http://dx.doi.org/10.4028/www.scientific.net/ast.84.45.

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At night, weakly electric fish Gnathonemus petersii use active electrolocation to scan their environment with self generated electric fields. Nearby objects distort the electric fields and are recognized as electric images on the electroreceptive skin surface of the animal. By analyzing the electric image, G. petersii can sense an object’s distance, dimensions and electrical properties. The principles and algorithms of active electrolocation can be applied to catheter-based sensor systems for analysing wall changes in fluid filled tube systems, for example atherosclerotic plaques of the coronary blood vessels. We used a basic atherosclerosis model of synthetic blood vessels and plaques, which were scanned with a ring electrode catheter applying active electrolocation. Based on the electric images of the plaques and the evaluation of bio-inspired image parameters, the plaque’s fine-structure could be assessed. Our results show that imaging through active electrolocation principally has the potential to detect and characterize atherosclerotic lesions.

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Wang, Chenghang, Chunya Li, Li Ting, Xiuling Xu y Changfa Wang. "Application of a Single-Wall Carbon Nano-Tube Film Electrode to the Determination of Trace Amounts of Folic Acid". Microchimica Acta 152, n.º 3-4 (30 de noviembre de 2005): 233–38. http://dx.doi.org/10.1007/s00604-005-0441-5.

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22

Ohgoe, Yasuharu y Kenji K. Hirakuri. "Diamondlike carbon film deposition on a polycarbonate-tube inner wall using a cylindrical electrode with radio frequency glow discharge plasma". Journal of Applied Physics 97, n.º 2 (15 de enero de 2005): 024906. http://dx.doi.org/10.1063/1.1832751.

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23

Yu, Ru-Jun, Guang-Yi Cao, Xiu-Qing Liu, Zhong-Fang Li, Wei Xing y Xin-Jian Zhu. "Fabrication of Support Tubular Proton Exchange Membrane For Fuel Cell". Journal of Fuel Cell Science and Technology 4, n.º 4 (17 de abril de 2006): 520–24. http://dx.doi.org/10.1115/1.2759501.

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The support tubular proton exchange membranes (STPEMs) were fabricated successfully by impregnating porous silica pipe into a solution of perfluorinated resin. The structures of the inner, outer, and cross section of support PEM tube were characterized intensively by scanning electron microscopy observation. In addition, the conductivity and impermeability were measured by electrochemical impedance spectroscopy (EIS) and the bubble method, respectively. Results show that the conductivity of the PEM can reach as low as 1.46S∕m when using the silica pipe of 0.7mm wall thickness. Subsequently, the ST membrane electrode assembly for direct methanol fuel cell (DMFC) and proton exchange membrane fuel cell (PEMFC) applications was prepared first by loading Pt∕C and Pt–Ru∕C catalyst ink onto the outer and inner surfaces of the PEM tube, respectively. The performances of the tubular DMFC and the PEMFC were tested on a self-made apparatus, which shows that the power density of tubular DMFC can reach 10mWcm−2 when 4molL−1 methanol solution flows through the anode at 80°C, and that the power density of tubular PEMFC can reach up to 60mWcm−2 when hydrogen flows at the rates of 20mlmin−1 through the anode at 60°C, both the cathodes adopting air-breathing mode.

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Ivanova, Natalia, Elizaveta Martynova, Anna Vershinina, Maksim Lomakin, Galina Eremeeva, Olesya Gordaya y Sergey Shandakov. "Electrochemical Sensors Based on Single-Wall Carbon Nanotubes in Voltammetric Ascorbic Acid Tests". Food Processing: Techniques and Technology 53, n.º 4 (30 de diciembre de 2023): 824–31. http://dx.doi.org/10.21603/2074-9414-2023-4-2482.

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Modern highly sensitive and selective sensors are able to determine biologically active substances, which makes this direction one of the most popular areas of analytical chemistry. The study featured the electrochemical properties of new fiber materials based on single-wall carbon nanotubes with prospects of using them in the voltammetry of ascorbic acid. The authors developed a new technology to synthesize films from disordered single-wall carbon nanotubes by chemical vapor deposition. Fibers were produced from a solvent by wet-pulling of single-wall carbon nanotubes networks. Thin films of randomly oriented single-wall carbon nanotube bundles were deposited downstream of a floating aerosol CVD reactor, which included a high temperature furnace with a quartz tube. The synthesis of the single-wall carbon nanotube samples was performed at 825°C. Ethanol served as carbon source while ferrocene was used as catalyst precursor. The single-wall carbon nanotubes were collected on a nitrocellulose filter in the form of films with transmittances of 10% in the middle of the visible wavelength (550 nm). The method was optimized to involve air annealing at 300–320°C and a treatment with strong inorganic acids, i.e., HCl, HNO3 + H2SO4. The voltammetric curves recording included background electrolyte, scan rate, and preconditioning. These parameters were selected experimentally to obtain the maximal sensor response to ascorbic acid content. The anodic peak of ascorbic acid in the phosphate buffer electrolyte (pH 6.86) was observed at a potential of +0.2 V. The current and peak area of ascorbic acid oxidation depended neither on the time nor on the conditioning potential of the sensor. The linear dependences of these parameters on the concentration of ascorbic acid stayed within 50–500 μmol/L (8.8–90 mg/L) at a scan rate of 0.1 mV/s. The single-wall carbon nanotube microsensor had a length of 0.5 cm and an average width of 400 μm. Its sensitivity was two times as high as that of a disk glassy carbon electrode with a diameter of 5 mm. The experimental sensors proved effective in determining ascorbic acid in food products, pharmaceuticals, and biological fluids.

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Cui, Ziqiang, Chengyi Yang, Benyuan Sun y Huaxiang Wang. "Liquid Film Thickness Estimation using Electrical Capacitance Tomography". Measurement Science Review 14, n.º 1 (1 de febrero de 2014): 8–15. http://dx.doi.org/10.2478/msr-2014-0002.

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Abstract In air/oil lubrication systems, the flow parameters, e.g., flow pattern, liquid film thickness, and air/oil flow rate, are of great importance to the transportation efficiency. In most cases, the on-going two-phase flow is annular flow with the oil moving along the tube wall and the air travelling at high speed in the center. This usually results in the formation of a thin oil film, the thickness of which is a key parameter determining the efficiency of the lubrication system. As the oil film thickness of the on-going air/oil flow varies dynamically, there is actually no applicable method for a non-intrusive test. In this paper, the use of electrical capacitance tomography (ECT) to investigate the air/oil flow has been studied. Capacitance measurements are made from an externally mounted electrode array in a non-invasive and non-intrusive manner. Both average and distributed oil film thicknesses can be calculated from the reconstructed ECT images. Simulation and experimental results show that the ECT technique can provide satisfactory results of online oil film thickness estimation

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Gupta, S. "Ion transport and electrochemical tuning of Fermi level in single-wall carbon nanotubes: In situ Raman scattering". Journal of Materials Research 22, n.º 3 (marzo de 2007): 603–14. http://dx.doi.org/10.1557/jmr.2007.0087.

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The in situ Raman spectroscopy technique was used to investigate the ion transport and to determine the concomitant electrochemical tuning of Fermi level in single-wall carbon nanotubes. The variation of structural bonding in a single-wall carbon nanotube bundle dipped in aqueous alkaline earth halide electrolyte such as CaCl2 with electrochemical biasing was monitored. This is because Raman scattering can detect changes in C–C bond length through radial breathing mode (RBM) at ∼184 cm−1, which varies inversely with the nanotube diameter and the G band at ∼1590 cm−1, varying with the axial bond length. Consistent reversible and substantial variation in Raman intensity of both modes was induced by electrode potential point at the fine and continuous tuning (alternatively, emptying/depleting or filling) of the specific bonding and anti-bonding molecular states. Qualitatively, the results were explained in terms of changes in the energy gap occurring between the one-dimensional van Hove singularities present in the electron density of states, possibly arising due to the alterations in the overlap integral of π bonds between the p orbitals of the adjacent carbon atoms. We estimated the extent of variation of the absolute potential of the Fermi level and overlap integral (γ0) between the nearest-neighbor carbon atoms by modeling the electrochemical potential dependence of Raman intensity. Observations also suggested that the work function of the tube becomes larger for the metallic nanotubes in contrast to the simultaneously present semiconducting nanotubes.

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27

Kovaľ, Vladimír. "High aspect ratio lead zirconate titanate tube structures: II. Directed assembly via dielectrophoresis". Processing and Application of Ceramics 6, n.º 1 (2012): 43–51. http://dx.doi.org/10.2298/pac1201043k.

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This paper reports on the controlled manipulation of high aspect ratio ferroelectric microtubes on pre-patterned templates by dielectrophoresis. Microtubes of ferroelectric lead zirconate titanate (PZT, a chemical formula of Pb(Zr0.52Ti0.48 )O3) with an outer diameter of 2 ?m, a length of about 30 ?m and a wall thickness of 400 nm were prepared by vacuum infiltration method using macroporous silicon templates. To position and align tubes at designed places, an alternating electric field was applied to a colloidal suspension of PZT tubes through lithographically defined microelectrodes. This would enable creation of a stable electrical connection to individual tubes for making a testing structure for rapid electrical characterization. Electric-field assisted assembly experiments demonstrated that the frequency and magnitude of the applied electric field control dielectrophoretic long-range forces, and hence spatial movement of the tubes in a non-uniform electric field. The most efficient biasing for the assembly of tubes across the electrode gap of 12 ?m was a square wave signal of 5 Vrms and 10 Hz. By varying the applied frequency in between 1 and 10 Hz, an enhancement in tube alignment was observed due to possible changes in dielectrophoretic torque. The results indicate a great potential for utilizing dielectrophoresis in construction of more complex, hierarchical 3-D device structures using the PZT 1-D like tubes as the building units.

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28

Reza Shishehbore, Masoud, Shohreh Vafai-Shahi, Faezeh Shefaie y Hosein Ali Meshayekhee. "Differential Pulse Voltammetry Technique for the Determination of Imipramine, Dopamine and Norepinephrine Using a Hydroquinone Derivative Multi-wall Carbon Nano-tube Carbon Paste Electrode". Oriental Journal of Chemistry 33, n.º 2 (25 de abril de 2017): 1017–20. http://dx.doi.org/10.13005/ojc/330257.

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29

Venkatachalam, Subramanian, Robert J. Angelici, L. Keith Woo y Andrew C. Hillier. "High Rate Detection of Volatile Products Using Differential Electrochemical Mass Spectrometry: Combining an Electrode-Coated Membrane with Hydrodynamic Flow in a Wall-Tube Configuration". Analytical Chemistry 85, n.º 12 (6 de junio de 2013): 6059–65. http://dx.doi.org/10.1021/ac400928p.

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30

Lee, Kwang-Jae, Rita Vos, Jozef Janssens y Jan Tack. "Influence of duodenal acidification on the sensorimotor function of the proximal stomach in humans". American Journal of Physiology-Gastrointestinal and Liver Physiology 286, n.º 2 (febrero de 2004): G278—G284. http://dx.doi.org/10.1152/ajpgi.00086.2003.

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Decreased acid clearance and increased exposure to acid of the duodenum have been reported in a subset of functional dyspepsia patients. However, the mechanism by which increased duodenal acid exposure may affect symptoms is unclear. The aim of the present study was to investigate the effects of duodenal acidification on proximal gastric tone and mechanosensitivity in humans. An infusion tube with a pH electrode attached was positioned in the second part of the duodenum, and a barostat bag was located in the gastric fundus. In 12 healthy subjects, fundic tone and sensitivity to distensions were assessed before and during duodenal infusion of 0.1 N hydrochloric acid or saline in a randomized, double-blind design. In 10 healthy subjects, meal-induced accommodation was measured during duodenal infusion of acid or saline. Acid infusion in the duodenum significantly increased fundic compliance and decreased fasting fundic tone. This was accompanied by a significant decrease in the pressures and the corresponding wall tensions at the thresholds for discomfort. During infusion of acid, significantly higher perception and symptom scores were obtained for the same distending pressures. The meal-induced fundic relaxation was significantly smaller during acid infusion compared with saline infusion. In conclusion, duodenal acidification induces proximal gastric relaxation, increases sensitivity to gastric distension, and inhibits gastric accommodation to a meal. Through these mechanisms, increased duodenal acid exposure may be involved in the pathogenesis of dyspeptic symptoms.

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31

Hadj Ahmed, Asmaa, Jean-Vincent Daurelle y Vincent Fourmond. "Optimizing the mass transport of wall-tube electrodes for protein film electrochemistry". Electrochimica Acta 403 (enero de 2022): 139521. http://dx.doi.org/10.1016/j.electacta.2021.139521.

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32

Melville, James L., Barry A. Coles, Richard G. Compton, Nafeesa Simjee, Julie V. Macpherson y Patrick R. Unwin. "Hydrodynamics and Mass Transport in Wall Tube and Microjet Electrodes. Simulation and Experiment for Micrometer-Scale Electrodes". Journal of Physical Chemistry B 107, n.º 1 (enero de 2003): 379–86. http://dx.doi.org/10.1021/jp021361z.

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33

Suzuki, Ikuro, Mao Fukuda, Shota Amano y Masao Gotoh. "High Sensitive Electrochemical Measurements of Neurotransmitters Using Multi-Wall Carbon Nano-Tube Electrodes". IEEJ Transactions on Electronics, Information and Systems 133, n.º 11 (2013): 2068–74. http://dx.doi.org/10.1541/ieejeiss.133.2068.

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34

Yoshida, Kazunari, Daichi Yokomizo y Takaaki Komatsu. "Production of Special Tubes with a Variety Cross-Sectional Shapes by Bunch Drawing and Fluid-Mandrel Drawing". Key Engineering Materials 622-623 (septiembre de 2014): 731–38. http://dx.doi.org/10.4028/www.scientific.net/kem.622-623.731.

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Recently, special tubes for high efficiency heat exchangers, high functionality electrodes, and super-micro medical needles have attracted attention. In order to produce such special tubes, however, a special processing method or tool is required. In this study, fabrication of special tube by bunch drawing and fluid-mandrel drawing were attempted. And it was revealed that the fabrication of special tubes with a variety of cross-sectional shape is possible, when a bunch of tubes, or a tube of large diameter in which a number of fine tubes are inserted, is drawn. Presumption of cross-sectional shapes after bunch drawing was examined by FE analysis. Cross-sectional shapes and the distribution of Vickers hardness which has relation to equivalent strain were compared between tubes obtained virtually by FE analysis and fabricated actually in this study. It was found that they correspond very well and FE analysis is useful for the presumption of cross-sectional shapes after bunch drawing. Meanwhile, downsizing of medical needles and heat exchanger tubes has been required from the market. So it is necessary to fabricate an inner-grooved fine tube with thin wall-thickness, and at that time the inner grooved geometry must be homothetic. Hollow sinking was carried out to reduce the diameter of a tube. And cross-sectional shape, groove geometry, and the change of wall thickness after processing were examined. In hollow sinking, increase of wall-thickness, change of inner groove geometry, and poor inner surface quality were found. Therefore, newly-devised fluid-mandrel drawing was applied. And it was revealed that it is possible to obtain an inner grooved tube of which groove shape is nearly similar to that of pre-processed tube, even after the processing of diameter reduction. Also, it was clarified that the production of a medical painless needle of 0.2mm in diameter by fluid-mandrel drawing was possible.

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35

LI, JINGQI, QING ZHANG, MARY B. CHAN-PARK y YEHAI YAN. "ANNEALING EFFECTS ON ELECTRIC CONTACTS BETWEEN CARBON NANOTUBES AND ELECTRODES". International Journal of Nanoscience 05, n.º 04n05 (agosto de 2006): 401–6. http://dx.doi.org/10.1142/s0219581x06004541.

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Single wall carbon nanotubes suspended in isopropyl alcohol are placed between two Au electrodes by ac dielectrophoresis method. Total resistance including the contact resistance and intrinsic tube resistance is found to decrease from 105–106 Ω for as-prepared samples to 104 Ω after annealing at 300°C in ambient environment. Measured I–V curves and Schottky barrier heights suggest that the electric contacts are changed from Schottky to Ohmic characteristics after annealing. These results demonstrate that annealing in ambient environment is a simple and efficient way to decrease the contact resistance.

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36

Melville, James, Nafeesa Simjee, Patrick R. Unwin, Barry A. Coles y Richard G. Compton. "Hydrodynamics and Mass Transport in Wall Tube and Microjet Electrodes. 1. Finite Element Simulations". Journal of Physical Chemistry B 106, n.º 10 (marzo de 2002): 2690–98. http://dx.doi.org/10.1021/jp013897a.

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37

Bogdanov, A. A., S. V. Gavrish, A. M. Martsinovsky y I. I. Stolyarov. "Influence of contraction of a cesium pulse-periodic discharge on its luminous efficacy and spectral properties". Journal of Physics: Conference Series 2103, n.º 1 (1 de noviembre de 2021): 012220. http://dx.doi.org/10.1088/1742-6596/2103/1/012220.

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Abstract The paper presents the results of a study of pulse-periodic discharge cesium lighting lamps with discharge tubes 5 mm in diameter and an interelectrode distance of 55 and 22 mm. The cesium pressure varied from 10 to 750 Torr at a constant triangular current pulse with an amplitude of 80 A. It is shown that the maximum of the luminous efficacy (~ 65 lm/W) corresponds to a pressure of ~ 130 Torr. It was found that a discharge column in the long tube at a pressure of ~ 300 Torr contracted into a bright pinch with a diameter close to that of the electrodes (2 mm). The pinch was localized along the surface of the tube and moves randomly on it. Contraction leads to a repeated increase in the luminous efficacy with pressure up to ~ 70 lm/W. Wall stabilization limits the plasma temperature on the axis of the pinch (it was found from the recombination continuum) to the level of 6000 – 6500 K. The column in short tube is localized along the axis of the tube over the entire power range. The temperature in it quickly rises to 13000-– 14000 K after the maximum of the luminous efficacy.

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38

Birhane, Yilma Tadesse, Sheam Chyun Lin y Te Yen Huang. "Variation of Entrance Length Effect on EHD Gas Pump Performance". Key Engineering Materials 649 (junio de 2015): 1–8. http://dx.doi.org/10.4028/www.scientific.net/kem.649.1.

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The effects of entrance length on performance and flow characteristic of EHD gas pump has been experimentally examined in this study. A 61.8mm-in-diameter EHD gas pump with eight evenly spaced emitting electrodes and flush mounted on the tube inner wall is used for this investigation. The experiment is conducted for two applied voltages 19 kV and 20kV with positive polarity. Several (L/D) ratios are used aiming at picking the appropriate length to achieve highest ionic discharge and maximum pump performance. Results show that the lowest (L/D) ratio gives the best pump performance with highest discharge managed.

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39

Rees, Neil V., Oleksiy V. Klymenko, Barry A. Coles y Richard G. Compton. "Hydrodynamics and Mass Transport in Wall-Tube and Microjet Electrodes: An Experimental Evaluation of Current Theory". Journal of Physical Chemistry B 107, n.º 49 (diciembre de 2003): 13649–60. http://dx.doi.org/10.1021/jp030883r.

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40

Ennaceri, Houda, Kristina Fischer, Kevin Hanus, Abdelkrim Chemseddine, Andrea Prager, Jan Griebel, Mathias Kühnert, Agnes Schulze y Bernd Abel. "Effect of Morphology on the Photoelectrochemical Activity of TiO2 Self-Organized Nanotube Arrays". Catalysts 10, n.º 3 (1 de marzo de 2020): 279. http://dx.doi.org/10.3390/catal10030279.

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In the present work, highly ordered titanium dioxide (TiO2) nanotube anodes were grown using a rapid anodization process. The photoelectrochemical performances of these electrodes strongly depend on the anodization conditions. Parameters such as electrolyte composition, anodization potential and anodization time are shown to affect the geometrical parameters of TiO2 nanotubes. The optimal anodization parameters are determined by photocurrent measurements, linear sweep voltammetry and electrochemical impedance spectroscopy. The thickness of the tube wall and its homogeneity is shown to strongly depend on the anodization potential, and the formation mechanism is discussed. This study permits the optimization of the photocurrent density and contributes to further improvement of the photoelectrochemical water-splitting performance of TiO2 nanotube photoelectrodes.

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41

Dolbnya, D. I., I. A. Znamenskaya, A. E. Lutsky y N. N. Sysoev. "Formation of Shock-Wave Flow during Nanosecond Discharge Localization in Unsteady Flow in a Channel with Obstacles". Известия Российской академии наук. Механика жидкости и газа, n.º 1 (1 de enero de 2023): 144–50. http://dx.doi.org/10.31857/s0568528122600308.

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The results of studies of the effect of volume and surface pulse discharges on high-speed gas flow in a rectangular shock-tube channel with a change in the profile (obstacle on the lower wall) are given. A single nanosecond surface discharge or a discharge with preionization induced by the plasma electrodes (combined discharge) was initiated in flow downstream of the shock wave with the Mach numbers Ms = 3.2–3.4. The obstacle determines the distribution of the parameters of flow past the obstacle and the pulse discharge plasma redistribution. The density fields of gas dynamic flow under the experimental conditions are obtained and compared with the discharge plasma distribution. It is shown that the shock-wave effect of the discharge on flow behind the obstacle continued from 25 to 70 μs.

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42

Ali, Shams B., Atsinafe B. Oshido, Andrew Houlton y Benjamin R. Horrocks. "Models for sensing by nanowire networks: application to organic vapour detection by multiwall carbon nanotube—DNA films". Nanotechnology 33, n.º 4 (8 de noviembre de 2021): 045502. http://dx.doi.org/10.1088/1361-6528/ac2e20.

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Abstract Electronic sensors for volatile organic compounds have been prepared by drop-casting dispersions of multi-wall carbon nanotubes (MWCNTs) in aqueous solutions of λ-DNA onto Pt microband electrodes. The MWCNTs themselves show a metal-like temperature dependence of the conductance, but the conductance of DNA/MWCNT composites has an activated component that corresponds to inter-tube tunneling. The resistance of the composite was modelled by a series combination of a term linear in temperature for the nanotubes and a stretched exponential form for the inter-tube junctions. The resistance may increase or decrease with temperature according to the composition and may be tuned to be almost temperature-independent at 67% by mass of DNA. Upon exposure to organic vapours, the resistance of the composites increases and the time-dependence of this signal is consistent with diffusion of the vapour into the composite. The fractional change in resistance at steady-state provides an analytical signal with a linear calibration and the presence of DNA enhances the signal and adjusts the selectivity in favour of polar analytes. The temperature dependence of the signal is determined by the enthalpy of adsorption of the analyte in the inter-tube junctions and may be satisfactorily modelled using the Langmuir isotherm. Temperature and pressure-dependent studies indicate that neither charge injection by oxidation/reduction of the analyte nor condensation of analyte on the device is responsible for the signal. We suggest that the origin of the sensing response is an adsorption of the analyte in the inter-tube regions that modulates the tunneling barriers. This suggests a general route to tuning the selectivity of MWCNT gas sensors using non-conductive polymers of varying chemical functionality.

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43

Melville, James L., Nafeesa Simjee, Patrick R. Unwin, Barry A. Coles y Richard G. Compton. "Hydrodynamics and Mass Transport in Wall Tube and Microjet Electrodes: Effect of Vortex Formation and Cell Geometry on Limiting Currents". Journal of Physical Chemistry B 106, n.º 40 (octubre de 2002): 10424–31. http://dx.doi.org/10.1021/jp021358f.

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44

Fukuda, Masafumi, Makoto Oishi, Tetsuya Hiraishi, Akihiko Saito y Yukihiko Fujii. "Pharyngeal motor evoked potentials elicited by transcranial electrical stimulation for intraoperative monitoring during skull base surgery". Journal of Neurosurgery 116, n.º 3 (marzo de 2012): 605–10. http://dx.doi.org/10.3171/2011.10.jns111343.

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Object The purpose of this study was to determine whether monitoring of pharyngeal motor evoked potentials (PhMEPs) elicited by transcranial electrical stimulation during skull base tumor surgery might be useful for predicting postoperative swallowing deterioration. Methods The authors analyzed PhMEPs in 21 patients during 22 surgical procedures for the treatment of skull base tumors. Corkscrew electrodes positioned at C3 or C4 and Cz were used to deliver supramaximal stimuli (220–550 V). Pharyngeal MEPs were recorded from the posterior wall of the pharynx through a modified endotracheal tube. The correlation between the final/baseline PhMEP ratio and postoperative swallowing function was examined. Results Postoperative swallowing function was significantly (p < 0.05), although not strongly (r = −0.47), correlated with the final/baseline PhMEP ratio. A PhMEP ratio < 50% was recorded during 4 of 22 procedures; in all 4 of these cases, the patients experienced postoperative deterioration of swallowing function. After 18 procedures, the PhMEP ratios remained > 50%; nevertheless, after 4 (22.2%) of these 18 procedures, patients showed deterioration of swallowing function. Conclusions Intraoperative PhMEP monitoring can be useful for predicting swallowing deterioration following skull base surgery, especially in patients with swallowing disturbances that are mainly due to reduction in the motor functions of the pharyngeal muscles.

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45

Qi, ZhiHua, Xi Wang, Yang Xia, Zhiguo Zhao, Dongping Liu, Shuhui Shi, Xiaorui Ji y Zhenyu Zhou. "The influence of liquid conductivity on pulsed discharge generated by a vertical falling liquid electrode device". Journal of Physics D: Applied Physics, 25 de octubre de 2022. http://dx.doi.org/10.1088/1361-6463/ac9d49.

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Abstract A novel atmospheric gas-liquid discharge device has been designed in this study to generate discharge directly around the vertical falling liquid column. The device is made up of a quartz tube, an H.V. electrode attached to the outer wall of the quartz tube, and a vertical falling liquid column acting as the liquid ground electrode in the quartz tube`s internal center. An ICCD camera and a 2D axisymmetric numerical modeling are used to analyze the temporal-spatial evolution of the pulsed discharge around the liquid electrode. The results of the experiment and simulation indicate that the propagation and sustaining time of the discharge are strongly dependent on applied voltage and liquid electrode conductivity. It is found that there is no discharge observed around the liquid electrode with a conductivity of 0.05 mS/cm. As the conductivity of the liquid electrode increases, the electric field applied in the gas phase increases. When the conductivity is greater than 0.05 mS/cm, the discharge is initiated around the intermediate region of the liquid electrode, then develops upwards and downwards along the liquid electrode. The discharge sustaining time increases with the increase of the conductivity and applied voltage. When the liquid electrode is replaced by the stainless-steel electrode, it is discovered that the discharge sustaining time of the stainless-steel electrode is lower than that of the liquid electrode at the same applied voltage. Analysis suggests that the prolonged discharge sustaining time is caused by the gas capacitance that is increased by water vapor released from the liquid electrode. The simulation results indicate that the discharge around the liquid electrode is constrained to the cone-shaped distribution by the non-uniform electric field around the liquid electrode when the conductivity increases to 200 mS/cm.

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46

Yu, Hanlin, Yugang Zhao, Zhihao Li, Chuang Zhao, Shuo Meng, Yu Tang, Chen Cao y Haiyun Zhang. "Analysis of wall thickness variation of copper tube electrode processed by ultrasonic vibration". International Journal of Advanced Manufacturing Technology, 11 de marzo de 2024. http://dx.doi.org/10.1007/s00170-024-13115-8.

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47

Tewari, R. y C. Friedrich. "Force Characterization and Rigidity Analysis of a Monolithic Cochlear Prosthesis Actuator". Journal of Medical Devices 3, n.º 2 (1 de junio de 2009). http://dx.doi.org/10.1115/1.3147506.

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Cochlear implants continue to be used in the treatment of profound deafness. Because of the tonotopic nature of the cochlea, more controlled insertion is perhaps the most important factor affecting device performance. The implant stiffness, and therefore the scala tympani (ST) wall contact force, contributes to insertion difficulties. Attempts to correlate the implant carrier structural properties and the intracochlear contact forces during insertion are limited. Researchers in the Michigan Center for Wireless Integrated Microsystems are developing perimodiolar-shaped silicon and parylene-based thin film cochlear electrode arrays and backing devices for a more controllable implantation. We report a method developed for measuring the thin film actuated electrode array rigidity to quantify the ST and modiolus wall contact forces during and after insertion. The method used a pneumatically actuated polyethylene terephthalate (PET) monolithic electrode actuator using pressurized air (0–200 kPa) for actuation. The prototype actuators consisted of PET tubes with an ID of 365 μm and a wall thickness of 58 μm. Force calculations using cantilever beam bending theory were performed to estimate the tube bending forces as a function of internal pressure and therefore variable structural stiffness. Based on estimations, a method was developed to measure such small forces avoiding the use of commercially available, relatively insensitive load cells. A fixture was fabricated incorporating two brass microcantilevers (reference and deflection arms) sensitive to sub-mN forces applied by the actuator on the deflection arm of the cantilevers. Microcantilver deflection data, captured by an interferometric microscope, was used to calculate the actuator force and eventually the reaction force acting on the actuator. The implant actuation forces ranged from 0–0.76 mN over an actuation pressure range of 0–140 kPa, from nearly straight to the relaxed perimodiolar post-implantation shape. For estimating the implant rigidity (EI), the actuator stiffness and the actuation pressure was correlated. The actuator stiffness at different actuation pressures was obtained both theoretically (using beam bending theory and PET tube structural properties) and experimentally (using the derived unconstrained actuator deflections at measured actuator forces). The theoretical and experimental stiffness values ranged from 3.6E-08 to 5.34E-07 N/μm and 2.5E-08 to 7.8E-06 N/μm respectively over the working pressure range. The calculated rigidity constant (EI) of the best prototype insertion tool from the experimental stiffness measurement was 6.71E06 Nμm2. The insertion tool-ST wall contact forces were calculated, using the estimated rigidity, in a hypothetical insertion situation. Force calculations assumed that the implant is equipped with actuator deflection feedback sensors and the actuator's stiffness remains constant over its entire length for a given operating pressure. A contact force of 1.19 mN was found acting on the cochlear ST wall when the insertion tool hits the wall and deflects by 200 μm at an actuation pressure of 140 kPa.

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48

Liu, Shuai, Li Liu, Hanyang Gu y ke wang. "Optimization and application of the concentric conductance probes in liquid film thickness measurement in a helically coiled tube". Measurement Science and Technology, 26 de abril de 2022. http://dx.doi.org/10.1088/1361-6501/ac6ab5.

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Abstract The liquid film distribution in the helically coiled tube (HCT) is affected by curvature-induced centrifugal force and gravity force, showing more complex characteristics than straight tubes. However, due to the limitation of the measurement technology, the relevant data on liquid film in HCT are still rare. In this paper, based on the time-multiplexed excitation-probing scheme, a type of non-intrusive concentric conductance probes (CCPs) is developed at first. After reporting the operation principle of CCPs, the numerical simulation of potential field distribution in CCPs is conducted, and the effects of electrode structure parameters and liquid film thickness on the performance of CCPs are then analyzed in detail. It is found that in a certain range, the larger the inner electrode and outer electrode diameter, the greater the signal penetration depth (i.e., the larger the measurement range of liquid film thickness). Finally, the spatio-temporal distribution of liquid film on the wall of the HCT is experimentally studied using the optimized CCPs. The results indicate that this probe can realize the high-frequency accurate capture of liquid film flow details such as the occurrence and evolution process of liquid film inversion and the fluctuation characteristics of liquid film in HCT. The wave frequency of the liquid film is demonstrated to be not consistent along the circumferential direction. Using Strouhal number and Lockhart-Martinelli parameter, the wave frequency correlation at the maximum film thickness in the state of film inversion in HCT is obtained.

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49

Liu, Shuai, Li Liu, Hanyang Gu y ke wang. "Optimization and application of the concentric conductance probes in liquid film thickness measurement in a helically coiled tube". Measurement Science and Technology, 26 de abril de 2022. http://dx.doi.org/10.1088/1361-6501/ac6ab5.

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Abstract The liquid film distribution in the helically coiled tube (HCT) is affected by curvature-induced centrifugal force and gravity force, showing more complex characteristics than straight tubes. However, due to the limitation of the measurement technology, the relevant data on liquid film in HCT are still rare. In this paper, based on the time-multiplexed excitation-probing scheme, a type of non-intrusive concentric conductance probes (CCPs) is developed at first. After reporting the operation principle of CCPs, the numerical simulation of potential field distribution in CCPs is conducted, and the effects of electrode structure parameters and liquid film thickness on the performance of CCPs are then analyzed in detail. It is found that in a certain range, the larger the inner electrode and outer electrode diameter, the greater the signal penetration depth (i.e., the larger the measurement range of liquid film thickness). Finally, the spatio-temporal distribution of liquid film on the wall of the HCT is experimentally studied using the optimized CCPs. The results indicate that this probe can realize the high-frequency accurate capture of liquid film flow details such as the occurrence and evolution process of liquid film inversion and the fluctuation characteristics of liquid film in HCT. The wave frequency of the liquid film is demonstrated to be not consistent along the circumferential direction. Using Strouhal number and Lockhart-Martinelli parameter, the wave frequency correlation at the maximum film thickness in the state of film inversion in HCT is obtained.

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50

Aldinio-Colbachini, Anna, Alain Grossi, Américo G. Duarte, Jean-Vincent Daurelle y Vincent Fourmond. "Combining a Commercial Mixer with a Wall-Tube Electrode Allows the Arbitrary Control of Concentrations in Protein Film Electrochemistry". Analytical Chemistry, 11 de marzo de 2024. http://dx.doi.org/10.1021/acs.analchem.3c05293.

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