A Direct-Reading MEMS Conductivity Sensor with a Parallel-Symmetric Four-Electrode Configuration

Liu, Zhiwei; Jing, Junmin; Gao, Rui; Guo, Yuzhen; Ye, Bin; Zhang, Huiyu; Zhao, Zhou; Zhang, Wenjun; Wang, Yonghua; Zhang, Zengxing; Chen, Xue

doi:10.3390/mi13071153

Cited by 8 publications

(5 citation statements)

References 25 publications

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“…However, the size of an inductive sensor is large because of a toroidal transformer which limits its miniaturization. Electrode sensors measure salinity with a conductivity cell whose parameter corresponds to the size and shape of electrodes [ 50 ]. The design of a conductivity cell is the most important aspect of electrode conductivity sensor design.…”

Section: Conductivity/salinity Sensorsmentioning

confidence: 99%

“…A direct-reading MEMS conductivity sensor with a parallel-symmetric four-electrode configuration which integrates a silicon-based platinum thin film strip electrode and a serpentine temperature compensation electrode was proposed by Zhiwei Liao [ 50 ]. As shown in Figure 2 a, the voltages and current electrodes are separated to weaken the polarization phenomenon.…”

Section: Conductivity/salinity Sensorsmentioning

confidence: 99%

See 1 more Smart Citation

CTD Sensors for Ocean Investigation Including State of Art and Commercially Available

Xiao

Zhang

Liu

et al. 2023

Sensors

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Over 70% of the earth’s surface is covered by oceans; globally, oceans provides a huge source of wealth to humans. In the literature, several sensors have been developed to investigate oceans. Electrical conductivity temperature depth (CTD) sensors were used frequently and extensively. Long-term accurate CTD data is important for the study and utilization of oceans, e.g., for weather forecasting, ecological evolution, fishery, and shipping. Several kinds of CTD sensors based on electrics, optical, acoustic wave and radio waves have been developed. CTD sensors are often utilized by measuring electrical signals. The latest progress of CTD sensors will be presented in order of performance. The principles, structure, materials and properties of many CTD sensors were discussed in detail. The commercially available CTD sensors were involved and their respective performances were compared. Some possible development directions of CTD sensors for ocean investigation are proposed.

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Section: Conductivity/salinity Sensorsmentioning

confidence: 99%

Section: Conductivity/salinity Sensorsmentioning

confidence: 99%

CTD Sensors for Ocean Investigation Including State of Art and Commercially Available

Xiao

Zhang

Liu

et al. 2023

Sensors

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“…However, this measurement method suffers from errors caused by electrode polarization [24][25][26]. Therefore, the proposed module adopts a four-electrode conductivity sensor [27] to separate the current and voltage electrodes. Namely, the voltage electrodes are between the current electrodes, and the four electrodes are in the same plane.…”

Section: Conductivity Sensor Conditioning Circuitmentioning

confidence: 99%

A Hardware System for Synchronous Processing of Multiple Marine Dynamics MEMS Sensors

et al. 2022

Self Cite

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Temperature, depth, conductivity, and turbulence are fundamental parameters of marine dynamics in the field of ocean science. These closely correlated parameters require time-synchronized observations to provide feedback on marine environmental problems, which requires using sensors with synchronized power supply, multi-path data solving, recording, and storage performances. To address this challenge, this work proposes a hardware system capable of synchronously processing temperature, depth, conductivity, and turbulence data on marine dynamics collected by sensors. The proposed system uses constant voltage sources to excite temperature and turbulence sensors, a constant current source to drive a depth sensor, and an alternating current (AC) constant voltage source to drive a conductivity sensor. In addition, the proposed system uses a high-precision analog-digital converter to acquire the direct current (DC) signals from temperature, depth, and turbulence sensors, as well as the AC signals from conductivity sensors. Since the sampling frequency of turbulence sensors is different from that of the other sensors, the proposed system stores the generated data at different storage rates as multiple-files. Further, the proposed hardware system manages these files through a file system (file allocation tab) to reduce the data parsing difficulty. The proposed sensing and hardware logic system is verified and compared with the standard conductivity-temperature-depth measurement system in the National Center of Ocean Standards and Metrology. The results indicate that the proposed system achieved National Verification Level II Standard. In addition, the proposed system has a temperature indication error smaller than 0.02 °C, a conductivity error less than 0.073 mS/cm, and a pressure error lower than 0.8‰ FS. The turbulence sensor shows good response and consistency. Therefore, for observation methods based on a single point, single line, and single profile, it is necessary to study multi-parameter data synchronous acquisition and processing in the time and spatial domains to collect fundamental physical quantities of temperature, salt, depth, and turbulence. The four basic physical parameters collected by the proposed system are beneficial to the in-depth research on physical ocean motion, heat transfer, energy transfer, mass transfer, and heat-energy-mass coupling and can help to realize accurate simulation, inversion, and prediction of ocean phenomena.

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“…For pH sensors and flow rate sensors, due to their complex structure and large volume, it is difficult to integrate them on silicon electrodes [17][18][19]. Temperature sensors and four electrode conductivity sensors [20,21] are relatively simple, and their structure is in micro level. So, theoretically, it is possible to integrate temperature sensors and four-electrode conductivity sensors on silicon electrodes.…”

Section: Introductionmentioning

confidence: 99%

Design and fabrication of a sensors-integrated silicon electrode for gap status monitoring in micro electrochemical machining

Zhu,

Liu,

et al. 2024

J. Micromech. Microeng.

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The monitoring of micro machining gap and the control of machining status within the gap have become bottlenecks in the research and development of micro electrochemical machining (ECM). General electrical signals are difficult to reflect the status of micro machining gap. Electrolytic products in micro machining gap are prone to precipitation and retention, leading to unstable material removal process. Micro ECM urgently requires gap status monitoring and feedback control. To realize gap status monitoring, a sensors-integrated silicon electrode, with a micro temperature sensor and a micro conductivity sensor on the silicon electrode near-front sidewall, is proposed innovatively in this study. Based on bulk silicon process and electroplating process, sensors-integrated silicon electrodes are designed and fabricated. Based on the signal processing system built for the temperature and conductivity sensor, the temperature and conductivity detection functions are verified and the sensors are calibrated. Micro ECM experiments with sensors-integrated silicon electrodes are carried out and micro holes with 200 μm depth are machined. For the conductivity sensor on the sensors-integrated silicon electrode, due to the affection of electrolytic environment, the function surface is contaminated and damaged, and the structural design needs to be further improved. For the temperature sensor, it is not affected by the electrolytic environment due to insulation-film’s protection, and reliable temperature monitoring is achieved in micro ECM. The detection results indicate that the temperature inside the machining gap has increased by 20 ℃ due to the electrochemical thermal effect and resistance thermal effect in micro ECM, and the temperature shows an increasing trend while machining depth increasing. The feasibility of process monitoring with sensors-integrated silicon electrode in micro ECM is preliminarily verified.

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A Direct-Reading MEMS Conductivity Sensor with a Parallel-Symmetric Four-Electrode Configuration

Cited by 8 publications

References 25 publications

CTD Sensors for Ocean Investigation Including State of Art and Commercially Available

CTD Sensors for Ocean Investigation Including State of Art and Commercially Available

A Hardware System for Synchronous Processing of Multiple Marine Dynamics MEMS Sensors

Design and fabrication of a sensors-integrated silicon electrode for gap status monitoring in micro electrochemical machining

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