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In this paper, a curve-shaped based doubly clamped piezoelectric energy harvester (CD-PEH) is explored for improving the energy harvesting performance. The harvester consists of a composed beam constructed with two arc-shaped structures and a flat beam, as well as two proof masses. A method based on chained beam constraint model theory (CBCM) is first applied to build the nonlinear restoring force model of the CD-PEH, the developed analytical model is validated by the finite element analysis (FEA). Then the electromechanically coupled model for the CD-PEH is built to investigate the effect of excitation amplitudes, geometric parameters and load resistance on the output characteristics. Due to the geometric nonlinearity caused by the arc-shaped configuration, the CD-PEH orderly exhibits quasi-linear, softening nonlinear and mixed hardening & softening nonlinearity behavior with the increasing of excitation level, which could effectively extend the frequency bandwidth of the system. For the excitation of A = 8 m/s2, the effective working bandwidth of the CD-PEH is increased by 633% compared with the effective bandwidth in the case of A = 2 m/s2. Moreover, comparison experiments demonstrate that the output voltage and the effective bandwidth are increased by 225 and 450%, respectively, compared with the typical doubly-clamped piezoelectric energy harvester (T-PEH) under the same excitation amplitude. Overall, this study provides a new way and theoretical framework for the design of high-efficiency doubly clamped piezoelectric energy harvester. [ABSTRACT FROM AUTHOR]

The emergence of the vibration energy harvesting system makes it possible for wireless monitoring nodes in coal mines to realize self-power supply. In order to reveal the influence of gravity effect on the response characteristics of the combined beam tri-stable piezoelectric energy harvesting system (CTEHS), the system's nonlinear magnetism is calculated according to the principle of point magnetic charge dipole, and the system's nonlinear resilience is obtained through experimental measurements and nonlinear fitting methods. Based on the Lagrange equation, the system's electromechanical coupling motion model considering gravity is established. The system's motion equation is solved numerically based on the Runge–Kutta algorithm, and the effects of the end magnet mass and the initial vibration point on the bifurcation behavior, potential energy, and system output performance are investigated by emulation and experiment. The research shows that the magnet's gravity effect causes a change in the stable equilibrium position and the system's motion state and also causes the system to generate additional gravitational potential energy, which leads to a potential asymmetric well of the system. Under the consideration of magnet gravity, the appropriate end magnet mass and initial vibration point can not only reduce the system's requirements for external excitation strength but also effectively improve the system's response and output. This research provides a new theoretical basis for the optimal design of the tri-stable piezoelectric energy harvesting system. [ABSTRACT FROM AUTHOR]

DNA is considered as a prospective candidate for the next‐generation data storage medium, due to its high coding density, long cold‐storage lifespan, and low energy consumption. Despite these advantages, challenges remain in achieving high‐fidelity, fully integrated, and cost‐efficient DNA storage system. In this study, a homemade digital microfluidic (DMF)‐based compact DNA data storing pipeline is orchestrated to complete the entire process from the synthesis to the sequencing. The synthetic half employs phosphoramidite chemistry on 200 nm magnetic beads (MBs), where the dimethyltrityl protecting group is removed by droplet manipulation of trichloroacetic acid. The sequencing counterpart relies on pyrophosphate releasing originated from polymerase‐catalyzed primer extension, which leads to photon‐countable chemiluminescence (CL) signal in 2.5‐μL drops of trienzyme cascading reactions. Further by DNA denaturation, repeated pyrosequencing plus plurality voting can improve the nucleobase accuracy beyond 95 %. As a proof‐of‐concept trial, semantic information is saved in DNA via the Huffman coding algorithm plus the Reed‐Solomon error‐correction, and then robustly retrieved from this streamlined platform. As a result, it took a net total of approximately 6.5 h to writing and reading 8 bytes of data, that equal to a storaging speed of 49 min/byte, much quicker than the previously reported 2.8–4.2 h/byte. This bead‐based miniaturized device promises an unattended protocol for achieving high‐throughput, full‐packaged, and above all, neatly precision DNA storage. [ABSTRACT FROM AUTHOR]

Botanical sourcing seriously impacts the safety and potency of herbal medicines, restricting the development of the traditional Chinese medicinal industry. Rapid and convenient identification of plant resources is important to address this problem. Herein, we innovated a portable, intelligent, and integrated platform, termed the Smart Electronic Tongue (SET), for right recognizing Dendrobium bonsai of different subspecies and origins. The device is miniaturized with a hollow microneedle array for leaf-face extraction, a press-pumping pipeline for on-demand sample sap suction, plus a five-electrode chip for electrochemical readout. Differential pulse voltammograms on three simplexes of self-assembled monolayers as well as their multiplexed configurations are specialized to generate high-dimensional fingerprinting of Dendrobium subtypes. Taking advantage of machine learning algorithms, the platform achieves automatic authentication over eight varieties with a discriminatory accuracy of 95%. Given this, we anticipate that such a bionic sensing setup would offer a versatile solution toward the classification of diverse officinals at the point of need.