Zinc Ion Triggered Controllable Binary/Ternary Memory Conversion Behaviors in Polyimides Containing Pendant Porphyrin Group.

Compared with typical binary polymeric memory materials, functional polymers with ternary memory performance possess significant potential to achieve ultra-high-density data storage. The reported ternary memory polymers are normally driven by dual-mechanism. However, the involved thermodynamically unstable mechanisms (field-induced conformation change or conductive filament formation/fracture) may result in the poor reliability of memory devices under high-temperature working atmosphere. Another strategy to realize ternary memory is introducing charge trapping/de-trapping mechanism by attaching charge trap atom/group at electron donor, which is proved not always effective. Moreover, the synergistic two mechanisms may have difficulty for clarifying the relationship between memory performance and chemical structures, which is the core issue of polymer memory materials. Besides, some multi-level memory materials need the cooperative participation of artificially setting compliance current, which is the extension of typical binary memory and may cause a more complicated technique and logic circuit. Herein, based on charge-transfer mechanism, a concise and effective strategy to realize ternary memory application is proposed. By inserting a Zn ion, the charge-transfer process occurring in electron donors can lead to the novel electrical tri-stability memory behaviors. This work can provide a novel idea for achieving reliable and intrinsic ternary high-density data storage applications.

Power flow analysis and optimal locations of resistive type superconducting fault current limiters.

Based on conventional approaches for the integration of resistive-type superconducting fault current limiters (SFCLs) on electric distribution networks, SFCL models largely rely on the insertion of a step or exponential resistance that is determined by a predefined quenching time. In this paper, we expand the scope of the aforementioned models by considering the actual behaviour of an SFCL in terms of the temperature dynamic power-law dependence between the electrical field and the current density, characteristic of high temperature superconductors. Our results are compared to the step-resistance models for the sake of discussion and clarity of the conclusions. Both SFCL models were integrated into a power system model built based on the UK power standard, to study the impact of these protection strategies on the performance of the overall electricity network. As a representative renewable energy source, a 90 MVA wind farm was considered for the simulations. Three fault conditions were simulated, and the figures for the fault current reduction predicted by both fault current limiting models have been compared in terms of multiple current measuring points and allocation strategies. Consequently, we have shown that the incorporation of the E-J characteristics and thermal properties of the superconductor at the simulation level of electric power systems, is crucial for estimations of reliability and determining the optimal locations of resistive type SFCLs in distributed power networks. Our results may help decision making by distribution network operators regarding investment and promotion of SFCL technologies, as it is possible to determine the maximum number of SFCLs necessary to protect against different fault conditions at multiple locations.