A skillful balance of theoretical considerations and practical know-how Backed by a team of expert contributors, the Second Edition of this highly acclaimed publication brings a solid understanding ...of impedance spectroscopy to students, researchers, and engineers in physical chemistry, electrochemistry, and physics. Starting with general principles, the book moves on to explain in detail practical applications for the characterization of materials in electrochemistry, semiconductors, solid electrolytes, corrosion, solid-state devices, and electrochemical power sources. The book covers all of the topics needed to help readers identify whether impedance spectroscopy may be an appropriate method for their particular research problem. The book helps readers quickly grasp how to apply their new knowledge of impedance spectroscopy methods to their own research problems through the use of unique features such as: * Step-by-step instructions for setting up experiments and then analyzing the results * Theoretical considerations for dealing with modeling, equivalent circuits, and equations in the complex domain * Best measurement methods for particular systems and alerts to potential sources of errors * Equations for the most widely used impedance models * Figures depicting impedance spectra of typical materials and devices * Extensive references to the scientific literature for more information on particular topics and current research This Second Edition incorporates the results of the last two decades of research on the theories and applications of impedance spectroscopy. Most notably, it includes new chapters on batteries, supercapacitors, fuel cells, and photochromic materials. A new chapter on commercially available measurement systems reflects the emergence of impedance spectroscopy as a mainstream research tool. With its balanced focus on both
theory and practical problem solving, Impedance Spectroscopy: Theory, Experiment, and Applications, Second Edition serves as an excellent graduate-level textbook as well as a hands-on guide and reference for researchers and engineers.
Bioelectricity (or bioelectromagnetism) relates to the study of biological electrical currents, and bioimpedance deals with the measurement of electrical conductivity. They are intimately linked to ...biomedical engineering, with major significance for development of novel medical devices, as well as the study of biological rhythms. This completely updated new edition remains the most comprehensive reference tool for this intricate, interdisciplinary field.The authors, both internationally recognized experts in the field, have thoroughly revised the entire text. It remains the only such work that discusses in detail dielectric and electrochemical aspects, as well as electrical engineering concepts of network theory. The highly effective, easy to follow organization has been retained, with new discussion of state-of-the-art advances in finite element analysis, endogenic sources, control theory, tissue electrical properties, and invasive measurements. There are two all new chapters on bioelectricity, along with an introduction to Geselowitz theory, the Maxwell basis of bioimpedance, and multivariate analysis as an alternative.* Increased emphasis on bioelectricity and potential clinical applications * Two all new chapters dealing with electrical properties of passive and excitable tissue * Expanded discussion of finite element modelling and a broad range of applications * Provides a complete?all in one? reference source for a multidisciplinary, complex field * Includes many additional figures and all improved, newly drawn illustrations throughout
This article describes a high-input-impedance, low-noise bioimpedance (BioZ) sensor interface IC for small-area dry-electrode cardio-respiratory signals monitoring. To facilitate high-precision BioZ ...sensing with high-impedance dry electrodes, the IC utilizes three key techniques as follows: 1) a bias control loop (BCL) to eliminate the excitation current mismatch, reducing the voltage fluctuation on high-impedance input; 2) a quiet-chopping current feedback instrumentation amplifier (QC-CFIA) to mitigate the input-signal-dependent noise; and 3) a full pre-charge (FPC) technique to cancel the input parasitic capacitance for impedance boosting. Manufactured in a 0.18-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> CMOS process, the BioZ prototype IC occupies an area of 0.4 mm2 while consuming 15.8- and 14.4-128.4-<inline-formula> <tex-math notation="LaTeX">\mu \text{W} </tex-math></inline-formula> current, respectively, from the amplifier and the excitation current generator (CG). With these proposed techniques, this IC achieves a high input impedance of 100 <inline-formula> <tex-math notation="LaTeX">\text{M}\Omega </tex-math></inline-formula> at 50 kHz, 0.5-<inline-formula> <tex-math notation="LaTeX">\text{m}\Omega /\surd </tex-math></inline-formula>Hz sensitivity at 1 Hz, and a 106-dB signal-to-noise ratio (SNR). A gel-free respiration and impedance cardiography (ICG) recording has been successfully demonstrated on the human body with four 0.45-cm2 dry electrodes.
Objective: To demonstrate the feasibility of everaging impedance plethysmography (IPG) for detection of pulse transit time (PTT) and estimation of blood pressure (BP). Methods: We first established ...the relationship between BP, PTT, and arterial impedance (i.e., the IPG observations). The IPG sensor was placed on the wrist while the photoplethysmography sensor was attached to the index finger to measure the PTT. With a cuff-based BP monitoring system placed on the upper arm as a reference, our proposed methodology was evaluated on 15 young, healthy human subjects leveraging handgrip exercises to manipulate BP/PTT and compared to several conventional PTT models to assess the efficacy of PTT/BP detections. Results: The proposed model correlated with BP fairly well with group average correlation coefficients of 0.88 ± 0.07 for systolic BP (SBP) and 0.88 ± 0.06 for diastolic BP (DBP). In comparison with the other PTT methods, PTT-IPG-based BP estimation provided a lower root-mean-squared-error of 8.47 ± 0.91 mmHg and 5.02 ± 0.73 mmHg for SBP and DBP, respectively. Conclusion: We conclude that the measurement of arterial impedance via IPG methods is an adequate indicator to estimate BP. The proposed method appears to offer superiority compared to the conventional PTT estimation approaches. Significance: Using impedance magnitude to estimate PTT offers promise to realize wearable and cuff less BP devices.
Electrical bioimpedance entails the measurement of the electrical properties of tissues as a function of frequency. It is thus a spectroscopic technique. It has been applied in a plethora of ...biomedical applications for diagnostic and monitoring purposes. In this tutorial, the basics of electrical bioimpedance sensor design will be discussed. The electrode/electrolyte interface is thoroughly described, as well as methods for its modelling with equivalent circuits and computational tools. The design optimization and modelling of bipolar and tetrapolar bioimpedance sensors is presented in detail, based on the sensitivity theorem. Analytical and numerical modelling approaches for electric field simulations based on conformal mapping, point electrode approximations and the finite element method (FEM) are also elaborated. Finally, current trends on bioimpedance sensors are discussed followed by an overview of instrumentation methods for bioimpedance measurements, covering aspects of voltage signal excitations, current sources, voltage measurement front-end topologies and methods for computing the electrical impedance.
The paper reports a results of series of interlaboratory comparisons of low impedance measurements at frequencies relevant for electrochemical impedance spectroscopy (EIS) of commercial lithium-ion ...cells. Two comparisons are presented. The first, bilateral comparison has focused on low impedance standards calibration in a full complex plane using digital sampling setups. The second comparison has focused on calibration and use of commercial 4-terminal battery EIS meters. Both comparisons have covered the impedance range from 50μ℧ to 100m℧ across the full complex plane in a frequency range from 0.01Hz up to 5kHz. Finally, the paper summarizes practices identified as critical for achieving measurement compatibility among various labs.
•Relevant for electrochemical impedance measurements of lithium-ion battery cells.•First interlaboratory comparison of low impedances in full complex plane.•First interlaboratory comparison of low impedance at frequencies down to 0.01Hz.
The broad spread of cooperative robots into many application domains has resulted in a demand for intuitive and effective solutions for teleoperated control. A relevant role in teleoperation has been ...assumed by impedance controllers, that allow the increase of stability and accuracy during interaction. This paper aims to test a teleoperation method based on an impedance controller, namely tele-impedance control, that is usable in unstructured environments since it relies only on wearable sensors. The proposed solution maps the joint stiffness and position of the human user, computed through six EMG and two M-IMU sensors, into the remote system to be teleoperated. We developed a 2-DoFs virtual task involving virtual physical interactions to compare the performance of our solution with the one of a traditional position-based controller. The study has been conducted on five healthy participants, who experienced both controllers in two different sessions. The tele-impedance approach has proved to be less physically demanding and more intuitive than the position-based one. Experimental data also allow us to investigate the strategy employed by the volunteers in the case of remote interactions, while using the two controllers. Of note, even though with the position controller the variation of subject impedance has no effect on the virtual arm, participants still tend to regulate both impedance and position of their own arm.
Introduction/Aims
Needle impedance‐electromyography (iEMG) is a diagnostic modality currently under development that combines intramuscular electrical impedance with concentric electromyography (EMG) ...in a single needle. We designed, manufactured, and tested a prototype iEMG needle in a cohort of wild‐type (WT) and SOD1G93A amyotrophic lateral sclerosis (ALS) mice to assess its ability to record impedance and EMG data.
Methods
A new six‐electrode, 26‐gauge, iEMG needle was designed, manufactured and tested. Quantitative impedance and qualitative “gestalt” EMG were performed sequentially on bilateral quadriceps of 16‐wk‐old SOD1G93A ALS (N = 6) and WT (N = 6) mice by connecting the needle first to an impedance analyzer (with the animal at rest) and then to a standard EMG system (with the animal fully under anesthesia to measure spontaneous activity and briefly during awakening to measure voluntary activity). The needle remained in the muscle throughout the measurement period.
Results
EMG data were qualitatively similar to that observed with a commercially available concentric EMG needle; fibrillation potentials were observed in 84% of the ALS mice and none of the WT mice; motor unit potentials were also readily identified. Impedance data revealed significant differences in resistance, reactance, and phase values between the two groups, with ALS animals having reduced reactance and resistance values.
Discussion
This work demonstrates the feasibility of a single iEMG needle conforming to standard dimensions of size and function. Further progress of iEMG technology for enhanced neuromuscular diagnosis and quantification of disease status is currently in development.
This review article provides a comprehensive overview of impedance-readout integrated circuits (ICs) for electrical impedance spectroscopy (EIS) applications. The readout IC, a crucial component of ...on-chip EIS systems, significantly affects key performance metrics of the entire system, such as frequency range, power consumption, accuracy, detection range, and throughput. With the growing demand for portable, wearable, and implantable EIS systems in the Internet-of-Things (IoT) era, achieving high energy efficiency while maintaining a wide frequency range, high accuracy, wide dynamic range, and high throughput has become a focus of research. Furthermore, to enhance the miniaturization and convenience of EIS systems, many emerging systems utilize two-electrode or dry electrode configurations instead of the conventional four-electrode configuration with wet electrodes for impedance measurement. In response to these trends, various technologies have been developed to ensure reliable operations even at two- or dry-electrode interfaces. This article reviews the principles, advantages, and disadvantages of techniques employed in state-of-the-art impedance-readout ICs, aiming to achieve high energy efficiency, wide frequency range, high accuracy, wide dynamic range, low noise, high throughput, and/or high input impedance. The thorough review of these advancements will provide valuable insights into the future development of impedance-readout ICs and systems for IoT and biomedical applications.
Objective: This study explores the feasibility of coupling Electrical Impedance Tomography (EIT) to a standard-of-care laparoscopic surgical stapler, stapler+EIT, with the long-term goal of enabling ...intraoperative tissue differentiation for tumor margin detection. Methods: Two custom printed-circuit-board-based electrode arrays with 60 and 8 electrodes, respectively, matching the stapler geometry, served as the jaws of an electrode-integrated surrogate stapler+EIT device. The device was evaluated through a series of simulations and bench-top imaging experiments of agar-gel phantoms and bovine tissue samples to evaluate the technique and determine optimal imaging parameters. Results: Electrodes localized to only one jaw (the 60-electrode side) of the stapler outperformed a dual-jaw distribution of electrodes. Using this one-sided electrode array, reconstructions achieved an Area-Under-the-Curve (AUC) ≥ 0.94 for inclusions with conductivity contrasts of ≥30% for any size considered on measured agar-gel tests, and an AUC of 0.80 for bovine tissue samples. Conclusion: A stapler+EIT algorithm has been tuned and evaluated on challenging phantom tests and demonstrated to produce accurate reconstructions. Significance: This work is an important step in the development of a surgical stapler+EIT technique for margin assessment.
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