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10 pages, 2121 KiB

Open AccessArticle

The Phase Modulating Micro-Mover Based on the MHD/MET System in the Reference Arm of the Scanning Interferometer

by Sergey Kalenkov, Pavel Skvortsov, Aleksandr Tarasenko, Dmitry Sharov and Alexander Shtanko

Micromachines 2022, 13(11), 1972; https://doi.org/10.3390/mi13111972 - 14 Nov 2022

Viewed by 1033

The possibility of using a magnetohydrodynamic drive (MHD) and amolecular-electronic transfer (MET) sensor as a single device for moving and precise control of the displacement of a movable mirror, which is part of a scanning interferometer, is considered. A prototype of such a [...] Read more.

The possibility of using a magnetohydrodynamic drive (MHD) and amolecular-electronic transfer (MET) sensor as a single device for moving and precise control of the displacement of a movable mirror, which is part of a scanning interferometer, is considered. A prototype of such a device was developed and experimentally studied. A digital holographic image of the test object was obtained using an optical scheme containing a scanning interferometer with an MHD drive. The important advantages of the MHD drive in the problems of digital recording of hyperspectral holographic images have been discussed. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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10 pages, 4968 KiB

Open AccessArticle

An Electrochemical Tilt Sensor with Double-Band Electrodes Fabricated by Wire Winding

by Yik-Kin Cheung and Hongyu Yu

Micromachines 2022, 13(8), 1229; https://doi.org/10.3390/mi13081229 - 31 Jul 2022

Viewed by 1591

Abstract

This paper presents the principle, design, fabrication, and characterization of Molecular Electronic Transducer (MET) dual-axis tilt sensors. The proposed sensor has a 3D-printed cylindrical channel inserted with four double-band electrodes and partially filled with a liquid electrolyte. The double-band electrodes were fabricated by [...] Read more.

This paper presents the principle, design, fabrication, and characterization of Molecular Electronic Transducer (MET) dual-axis tilt sensors. The proposed sensor has a 3D-printed cylindrical channel inserted with four double-band electrodes and partially filled with a liquid electrolyte. The double-band electrodes were fabricated by wire winding with a ~0.1 mm anode-cathode distance under controlled tension. It allows the electrode to become any 3D coil rather than a 2D structure by microfabrication and exhibits good repeatability (

\pm 10 %

). The tilting changes the electrolyte level and electrode-electrolyte contact area, resulting in Faradaic current changes. The x-axis and the y-axis sensitivity reach 0.121 V/° and 0.154 V/°, respectively. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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9 pages, 4109 KiB

Open AccessArticle

Self-Powered Galvanic Vibration Sensor

by Yik-Kin Cheung, Zuofeng Zhao and Hongyu Yu

Micromachines 2022, 13(4), 530; https://doi.org/10.3390/mi13040530 - 27 Mar 2022

Cited by 1 | Viewed by 2078

Abstract

The development of the IoT demands small, durable, remote sensing systems that have energy harvesters and storage. Various energy harvesters are developed, including piezoelectric, triboelectric, electromagnetic, and reverse-electrowetting-on-dielectric. However, integrating energy storage and sensing functionality receives little attention. This paper presents an electrochemical [...] Read more.

The development of the IoT demands small, durable, remote sensing systems that have energy harvesters and storage. Various energy harvesters are developed, including piezoelectric, triboelectric, electromagnetic, and reverse-electrowetting-on-dielectric. However, integrating energy storage and sensing functionality receives little attention. This paper presents an electrochemical vibration sensor with a galvanic cell (Zn-Cu cell) as energy storage and a vibration transducer. The frequency response, scale factor, long-term response, impedance study, and discharge characteristics are given. This study proved the possibility of integrating energy storage and vibration sensing functionality with promising performance. The performance of the sensor halved within 74 min. The longevity of the sensor is short due to the spontaneous reactions and ions drained. The sensitivity can be restored after refilling the electrolyte. The sensor could be rechargeable by changing to a reversible electrochemical system such as a lead–acid cell in the future. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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11 pages, 4048 KiB

Open AccessArticle

Influence of the Dielectric Coating of the Outer Side of the Cathode in the Anode–Cathode Pairs of a Molecular Electronic Sensitive Element on the Conversion Coefficient

by Alexander Bugaev, Victoria Agafonova, Ivan Egorov, Ekaterina Agafonova and Svetlana Avdyukhina

Micromachines 2022, 13(3), 360; https://doi.org/10.3390/mi13030360 - 24 Feb 2022

Cited by 6 | Viewed by 1373

Abstract

Molecular electronic sensors of motion parameters use miniature electrochemical cells as a sensitive element, in which the interelectrode current is sensitive to external mechanical influences. New approaches for creating conversion elements are based on precision methods of micromachining materials. The use of new [...] Read more.

Molecular electronic sensors of motion parameters use miniature electrochemical cells as a sensitive element, in which the interelectrode current is sensitive to external mechanical influences. New approaches for creating conversion elements are based on precision methods of micromachining materials. The use of new technologies has opened up the possibility of creating sensitive elements with configurations that have not been previously studied, and for which there is no clear understanding of the regularities that determine the output parameters depending on the geometry of the conversion elements. This work studies the influence of the dielectric coating on the surface of the cathodes on the conversion coefficient. The transforming structure has been made from three plates. The outer plates were an anode–cathode electrode pair. The middle plate served as a separator between the pairs of electrodes. It was found that an insulating layer on the side of the cathode facing away from the adjacent anode allows the conversion factor to be doubled. This result is applicable for a wide class of conversion elements made with microelectronic technologies, as well as structures made of mesh electrodes. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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12 pages, 25872 KiB

Open AccessArticle

A MEMS Electrochemical Seismometer Based on the Integrated Structure of Centrosymmetric Four Electrodes

by Yumo Duan, Anxiang Zhong, Yulan Lu, Jian Chen, Deyong Chen and Junbo Wang

Micromachines 2022, 13(3), 354; https://doi.org/10.3390/mi13030354 - 23 Feb 2022

Cited by 1 | Viewed by 1548

Abstract

This paper presented an electrochemical seismic micro sensor based on an integrated structure of four centrosymmetric electrodes. In this integrative structure, cathodes were not only distributed on wafer surfaces but also on the inner walls of the flow holes of the wafer, which [...] Read more.

This paper presented an electrochemical seismic micro sensor based on an integrated structure of four centrosymmetric electrodes. In this integrative structure, cathodes were not only distributed on wafer surfaces but also on the inner walls of the flow holes of the wafer, which increased the effective cathode areas and improved the sensitivity of the sensor. Numerical simulations were conducted to validate the feasibility of the integrated structure of four centrosymmetric electrodes in monitoring seismic vibrations where variations in the arrangements of the flow holes and anode width were investigated. The integrated structure of the four centrosymmetric micro electrodes was fabricated based on Micro-Electro-Mechanical Systems (MEMS) without the requirement of manual alignments. Experimental characterizations revealed that: (1) the maximum sensitivity of the electrochemical seismic sensor based on the integrated structure of four centrosymmetric electrodes was two orders of magnitude higher than that of the commercial counterpart of CME6011 and three times higher than the electrochemical seismic sensor based on the integrated structure of four planar micro electrodes; (2) the electrochemical seismic sensor based on the integrated structure of four centrosymmetric micro electrodes demonstrated comparable and even lower noise levels in comparison to CME6011. Thus, the electrochemical seismic micro sensor developed in this study may function as an enabling tool in future applications of seismic monitoring and geophysical explorations. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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16 pages, 2990 KiB

Open AccessArticle

Modeling of the Electrochemical Motion Sensor Conversion Factor at High Frequencies

by Vadim Agafonov, Iuliia Kompaniets, Bowen Liu and Jian Chen

Micromachines 2022, 13(2), 153; https://doi.org/10.3390/mi13020153 - 20 Jan 2022

Cited by 2 | Viewed by 2026

Abstract

The conversion factor of the electrochemical motion sensors at low frequencies is usually quite high. At the same time, it decreases significantly with the increase in frequency. Thus, increasing the conversion factor for high frequencies is essential for practical use. In this work, [...] Read more.

The conversion factor of the electrochemical motion sensors at low frequencies is usually quite high. At the same time, it decreases significantly with the increase in frequency. Thus, increasing the conversion factor for high frequencies is essential for practical use. In this work, the theoretical model that allows establishing the basic laws governing the conversion of high-frequency signals in an electrochemical cell has been suggested. The approach was based on the fact that in the case of high frequencies, the diffusion length is less than the distance between the electrodes and the thickness of the channel and it is enough to consider the transformation of the fluid motion into electrical current only near the cathodes. It was found that the signal output current can be represented as the sum of the term which is proportional to the steady-state concentration gradient along the surface on which the cathode is located, and the term proportional to the concentration gradient normal to the surface. Both first and second terms and the total signal current have been calculated for a particular case of a four-electrode planar system. The practical conclusion is that the high frequency conversion factor increases with the interelectrode distance and the channel width decreases compared to the cathode dimension. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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12 pages, 2654 KiB

Open AccessArticle

A Portable Sensor System with Ultramicro Electrode Chip for the Detection of Heavy-Metal Ions in Water

by Yuekun Wang, Yuhao Xu, Jinhua Jiang, Yang Li, Jianhua Tong and Chao Bian

Micromachines 2021, 12(12), 1468; https://doi.org/10.3390/mi12121468 - 28 Nov 2021

Cited by 8 | Viewed by 2184

Abstract

In this study, an ultramicro interdigital electrode array chip (UIEA) was designed and fabricated by using Micro-Electro-Mechanical systems (MEMS) technology, and a portable detection system, using the chip for determination of heavy-metal ions in water, was developed. The working electrode of the UIEA [...] Read more.

In this study, an ultramicro interdigital electrode array chip (UIEA) was designed and fabricated by using Micro-Electro-Mechanical systems (MEMS) technology, and a portable detection system, using the chip for determination of heavy-metal ions in water, was developed. The working electrode of the UIEA was modified with gold nanoparticles by electrodeposition. The detection sensitivity of the UIEA chip for copper ions was 0.0138 μA·L·μg⁻¹, with the linear range of 0–400 μg/L and the detection limit of 18.89 μg/L (3σ), which was better than that of the compared columnar glassy carbon electrode. The results of the interference experiment verified that the UIEA chip has a certain anti-interference ability against common heavy-metal ions in water, such as Pb²⁺, Zn²⁺, and Mg²⁺ ions. The standard addition method was used to investigate the performance of the developed s ystem for copper ion determination in real water. The recovery range from 87.5% to 94.7% was achieved. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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12 pages, 7913 KiB

Open AccessArticle

[OPy][BF₄] Selective Extraction for Trace Hg²⁺ Detection by Electrochemistry: Enrichment, Release and Sensing

by Chenyu Xiong, Yun Hui, Ri Wang, Chao Bian, Yuhao Xu, Yong Xie, Mingjie Han and Shanhong Xia

Micromachines 2021, 12(12), 1461; https://doi.org/10.3390/mi12121461 - 27 Nov 2021

Viewed by 1689

Abstract

Trace mercury ion (Hg

^{2 +}

) detection is important for environmental monitoring and water safety. In this work, we study the electrochemical strategy to detect trace Hg

^{2 +}

based on the preconcentration of temperature-controlled N-octylpyridinium tetrafluoroborate ([OPy][BF

_{4}

]) dispersive liquid–liquid [...] Read more.

Trace mercury ion (Hg

^{2 +}

) detection is important for environmental monitoring and water safety. In this work, we study the electrochemical strategy to detect trace Hg

^{2 +}

based on the preconcentration of temperature-controlled N-octylpyridinium tetrafluoroborate ([OPy][BF

_{4}

]) dispersive liquid–liquid microextraction. The [OPy][BF

_{4}

] selectively extracted Hg

^{2 +}

from aqueous solution by the adsorption of unsaturated N in [OPy][BF

_{4}

], which increased the concentration of Hg

^{2 +}

and decreased that of other interference ions. It was noted that the adsorption of [OPy][BF

_{4}

] to Hg

^{2 +}

was weakened by aqueous solution. Hence, after extraction, precipitated [OPy][BF

_{4}

] was diluted by a buffer solution comprising a mixture of water and acetonitrile to release Hg

^{2 +}

and the single was detected by electrochemistry. Water is proposed to release Hg

^{2 +}

adsorbed by [OPy][BF

_{4}

], and the acetonitrile serves as a co-solvent in buffer solution. Sensitivity and anti-inference ability of sensors were improved using the proposed method and Hg

^{2 +}

releasing procedure. The detection limit (S/N = 3) of the sensor is 0.0315

μg/L with a linear range from 0.1 to 1

μg/L. And the sensor exhibits good recovery with an range from 106 % to 118%, which has great potential for trace Hg

^{2 +}

determination. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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13 pages, 3636 KiB

Open AccessArticle

MEMS-Based Integrated Triaxial Electrochemical Seismometer

by Wenjie Qi, Bowen Liu, Tian Liang, Jian Chen, Deyong Chen and Junbo Wang

Micromachines 2021, 12(10), 1156; https://doi.org/10.3390/mi12101156 - 26 Sep 2021

Cited by 3 | Viewed by 2129

Abstract

This paper presents a micro-electromechanical systems (MEMS)-based integrated triaxial electrochemical seismometer, which can detect three-dimensional vibration. By integrating three axes, the integrated triaxial electrochemical seismometer is characterized by small volume and high symmetry. The numerical simulation results inferred that the integrated triaxial electrochemical [...] Read more.

This paper presents a micro-electromechanical systems (MEMS)-based integrated triaxial electrochemical seismometer, which can detect three-dimensional vibration. By integrating three axes, the integrated triaxial electrochemical seismometer is characterized by small volume and high symmetry. The numerical simulation results inferred that the integrated triaxial electrochemical seismometer had excellent independence among three axes. Based on the experimental results, the integrated triaxial electrochemical seismometer had the advantage of small axial crosstalk and could detect vibration in arbitrary directions. Furthermore, compared with the uniaxial electrochemical seismometer, the integrated triaxial electrochemical seismometer had similar sensitivity curves ranging from 0.01 to 100 Hz. In terms of random ground motion response, high consistencies between the developed integrated triaxial electrochemical seismometer and the uniaxial electrochemical seismometer could be easily observed, which indicated that the developed integrated triaxial electrochemical seismometer produced comparable noise levels to those of the uniaxial electrochemical seismometer. These results validated the performance of the integrated triaxial electrochemical seismometer, which has a good prospect in the field of deep geophysical exploration and submarine seismic monitoring. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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10 pages, 11003 KiB

Open AccessArticle

Design, Modeling and Simulation of a Liquid Jet Gyroscope Based on Electrochemical Transducers

by Dapeng Yang, Xiaohuan Wang, Junze Sun, Heng Chen, Chenhao Ju, Tingting Lin, Baofeng Tian and Fan Zheng

Micromachines 2021, 12(9), 1008; https://doi.org/10.3390/mi12091008 - 24 Aug 2021

Cited by 1 | Viewed by 1596

Abstract

We propose a novel liquid jet gyroscope based on electrochemical transducers, which uses electrolyte as the jet medium, and two electrochemical transducers placed symmetrically as the velocity measuring unit. The gyroscope includes a fluid pump to generate a jet flow, which flows into [...] Read more.

We propose a novel liquid jet gyroscope based on electrochemical transducers, which uses electrolyte as the jet medium, and two electrochemical transducers placed symmetrically as the velocity measuring unit. The gyroscope includes a fluid pump to generate a jet flow, which flows into the jet chamber. Then, it is diverged into the shunt channels, pumped into reflux channels and merged by a fluid pump. The velocities of shunt flows are measured by two electrochemical transducers. The feasibility of the method was demonstrated in theory, and a 2D finite element model was built to simulate the dynamics of the liquid jet gyroscope. Simulation results confirm the effectiveness of the gyroscope, which has higher sensitivity in the near DC frequency band. Full article

(This article belongs to the Special Issue Progress in Electrochemical Sensors)

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