Soft wearable electronics for underwater applications are of interest, but depend on the development of a waterproof, long-term sustainable power source. In this work, we report a bionic stretchable nanogenerator for underwater energy harvesting that mimics the structure of ion channels on the cytomembrane of electrocyte in an electric eel. Combining the effects of triboelectrification caused by flowing liquid and principles of electrostatic induction, the bionic stretchable nanogenerator can harvest mechanical energy from human motion underwater and output an open-circuit voltage over 10 V. Underwater applications of a bionic stretchable nanogenerator have also been demonstrated, such as human body multi-position motion monitoring and an undersea rescue system. The advantages of excellent flexibility, stretchability, outstanding tensile fatigue resistance (over 50,000 times) and underwater performance make the bionic stretchable nanogenerator a promising sustainable power source for the soft wearable electronics used underwater.

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A bionic stretchable nanogenerator for underwater sensing and energy harvesting.

More than energy harvesting – Combining triboelectric nanogenerator and flexible electronics technology for enabling novel micro-/nano-systems

Graphene-based wearable piezoresistive physical sensors

This expanded and thoroughly revised edition of Thomas H. Lee's acclaimed guide to the design of gigahertz RF integrated circuits features a completely new chapter on the principles of wireless systems. The chapters on low-noise amplifiers, oscillators and phase noise have been significantly expanded as well. The chapter on architectures now contains several examples of complete chip designs that bring together all the various theoretical and practical elements involved in producing a prototype chip. First Edition Hb (1998): 0-521-63061-4 First Edition Pb (1998); 0-521-63922-0

The Design of CMOS Radio-Frequency Integrated Circuits: RF CIRCUITS THROUGH THE AGES

Self-powered electronic skin based on the triboelectric generator

Detection and analysis of metal-salt solution are significant in many areas, especially for environmental monitoring. However, the complicated procedure and specific equipment are necessary, which is difficult to realize on-site rapid detection. In resent years, the arising of triboelectric nanogenerator attracts more and more investigation. Herein, a novel compact sensor for rapid detection of metal-salt solution droplet based on triboelectrification was developed. The proposed sensor enables to sense fundamental motion state and intrinsic property of test droplets, such as the concentration, with nonlinear responses produced in form of triboelectric pulses. Furthermore, the printed circuit board (PCB) technology was adopted to print interdigital electrodes for cost-effective fabrication. A thin film of polytetrafluoroethylene (PTFE) layer was prepared to cover electrodes, serving as a negative charged material in triboelectrification effect. As a functional dielectric material, PTFE with transferred electrons constructs electrostatic field, while interdigital electrodes collect electrons due to the electrostatic induction changed by the movement of liquid droplets. Therefore, according to the relation between the electric output signal and the features of droplet, the molarity, volume and type of measured droplet can be semi-quantitatively figured out. Thus, this triboelectrification-based method provides a new path to carry out a rapid and on-site detection of metal-salt solution droplet, and show an attractive potential toward a low-cost, portable and repeatable application.

Droplet Rapid-Analasis Method of Metal-Salt Solution Based on Triboelectric Effect

This article investigates a spurious resonance appearing near the antiresonance when the double-busbar configuration is applied to layered surface acoustic wave (SAW) resonators using 42 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^\circ$</tex-math> </inline-formula> YX-LiTaO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_3$</tex-math> </inline-formula> thin plates, and possible mitigation methods are studied both theoretically and experimentally. First, the origin of the spurious resonance is revealed, and the influence of structural parameters is studied using the periodic 3-D finite-element method (FEM) powered by the hierarchical cascading technique (HCT). Then, possible methods are discussed for spurious mitigation. Finally, experimental data are provided for validation of the present analysis. 

Spurious Mitigation of Layered Surface Acoustic Wave Resonators With Double-Busbar Configuration Using 42$^\circ$YX-Lithium Tantalate Thin Plate

This paper proposes a simple method to evaluate energy leakage and transverse mode behaviors of reflectors in incredible high-performance surface acoustic wave (I.H.P. SAW) resonator. Here, three different reflector designs are compared using this technique. First, models of different reflector structures are proposed, and the method to analyze these structures using 3D FEM are explained. Then, the proposed technique is used to simulate different reflectors and their results are compared. In addition, variation of gap and piston mode length are discussed for their influence to results.

A Simple Technique to Evaluate Lateral Leakage and Transverse Mode Behaviors of Reflectors in SH-Type SAW Resonator

This paper discusses the electrode configuration preferable for downsizing of SAW resonators. Here, use of heavy metal electrodes on low-cut LiNbO3 (LN) substrate is considered. First, variation of the SH-SAW velocity $V_{p}$ and electromechanical coupling factor $k^{2}$ is investigated with the electrode material choice. It is shown that heavy and stiff materials such as W is preferable for the purpose. Then, choice of the LN cut angle is also discussed for the Rayleigh-SAW suppression. Furthermore, use of double-layered electrode structure is discussed for reduction of electrode resistance. It is shown that use of soft, light and highly conductive material such as Al is preferable as the top layer in combination with the W bottom layer for minimizing $k^{2}$ deterioration.

Study of Electrode Configuration for Downsizing of SAW Resonators on Low-Cut Lithium Niobate

The invention discloses a resistance-changing capacitance-changing composite two-dimensional strain sensor and a preparation method thereof. The resistance-changing capacitance-changing composite two-dimensional strain sensor proposed by the invention is of a three-layer structure including an upper plate, an insulating dielectric layer and a lower plate of of a parallel plate capacitor in design.The conductive materials for the upper plate and the lower plate are selected from metals having a micro/nano structure, a carbon conductive materials or metal-carbon mixed conductive materials, thebipolar plate patterns are designed in a serpentine shape, and the upper plate and the lower plate of the capacitor are simultaneously used as a resistance-changing tensile strain sensor. The resistance-changing capacitance-changing composite two-dimensional strain sensor of the invention detects a tensile strain in a horizontal direction through a capacitance-changing phenomenon, detects a tensile strain in ae vertical direction through a resistance-changing phenomenon, and detects a tensile strain in a two-dimensional orthogonal direction by using the resistance-changing capacitance-changingcomposite form, so as to have flexible and tensile characteristics; and the resistance-changing tensile sensor adopts a permeable conductive network structure and has good sensitivity.

Jingfu Bao

Papers

Droplet Rapid-Analasis Method of Metal-Salt Solution Based on Triboelectric Effect

Spurious Mitigation of Layered Surface Acoustic Wave Resonators With Double-Busbar Configuration Using 42$^\circ$YX-Lithium Tantalate Thin Plate

A Simple Technique to Evaluate Lateral Leakage and Transverse Mode Behaviors of Reflectors in SH-Type SAW Resonator

Study of Electrode Configuration for Downsizing of SAW Resonators on Low-Cut Lithium Niobate

Resistance-changing capacitance-changing composite two-dimensional strain sensor and preparation method thereof