A fully soft generator with embedded conditioning circuitry

This letter presents a fully soft dielectric elastomer generator (DEG) based on a capacitive kinetic-energy-harvesting mechanism. First, using the principle of a passive charge pump, a self-cycling conditioning circuit topology is proposed. Through the electrical reciprocity of a cyclically deforming DEG and another capacitor in series with it, the generated charge can be continuously supplied to the load, via a bilateral conditioning bridge. The antagonistic dual-DEG scheme not only produces a larger potential to drive more charge in the flow but also provides a basic solution to soften the whole device. A further measure is to replace the bridge diodes with special dielectric elastic switches (DESs), which can be embedded into the DEG and synchronously deformed with the latter to control the on/off state of the circuit branches. The intrinsic physical mechanism and characteristics of the change in the resistance of the DES as a function of stretch and electric fields are investigated. We tested and compared the diode-bridge and DES-bridge schemes under different electrical loads and tensile strokes. The results indicate that under certain conditions, the DES-bridge circuit can achieve comparable performance with that of a conventional scheme, which suggests that a fully soft DEG system is possible. We experimentally evaluated and discussed its reliability in practice.Published versio

Capacitive energy harvesting using soft dielectric elastomers: Design, testing and impedance matching optimization

Energy harvesting based on dielectric elastomeric materials, in nature, embodies a capacitive kinetic energy conversion mechanism where the soft DE generator (DEG) interactively cooperates with conditioning circuits. Based on the principle of passive charge pump, this paper proposes a design concept for a self-cycling energy harvesting circuit driven by DEG cyclic deformation, with its essential behavioral mode laid on the electrical reciprocity between the DEG intrinsic capacitor and another capacitor connected in series. By detailed simulation experiments, the working process and dynamic characteristics of the proposed system, as well as the influence of circuital, operating, and load parameters on system performance are quantitatively investigated, with intensive discussions for the time delay behaviors caused by changes of load resistance, along with the different impacts of its value regions. Then, the theoretical analyses are effectively validated by experimental tests for a specially-designed annular DEG prototype. Under the global optimization framework based on impedance matching, this paper presents some guidelines for circuit design, e.g., the selection criteria of the capacitance and load resistance. In addition, the potential of this emerging technology is also demonstrated by experiments

Refining eligibility criteria of unit selection for myeloablative cord blood transplantation in acute leukemia: Real‐world experience of a referral center

Abstract The algorithm for cord blood (CB) unit selection is still somewhat ambiguous. We retrospectively analyzed 620 cases of acute leukemia between 2015 and 2020, who were treated with myeloablative single‐unit umbilical CB transplantation (UCBT). We found that, when human leukocyte antigen (HLA) mismatch was ≤3/10, CD34+ cell dosage <0.83 × 105/kg—considerably lower than prevalent guidelines—was permissible without affecting survival. Moreover, synergy between donor killer‐cell immunoglobulin‐like receptors (KIR) haplotypes‐B and donor‐recipient HLA‐C mismatch protected against relapse‐related mortality. We submit that minimum required CD34+ cell dosage can possibly be relaxed to broaden access to UCBT, and donor KIR genotyping should be considered during unit selection