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Molecular neuromorphic devices are composed of a random and extremely dense network of single-walled carbon nanotubes (SWNTs) complexed with polyoxometalate (POM). Such devices are expected to have the rudimentary ability of reservoir computing (RC), which utilizes signal response dynamics and a certain degree of network complexity. In this study, we performed RC using multiple signals collected from a SWNT/POM random network. The signals showed a nonlinear response with wide diversity originating from the network complexity. The performance of RC was evaluated for various tasks such as waveform reconstruction, a nonlinear autoregressive model, and memory capacity. The obtained results indicated its high capability as a nonlinear dynamical system, capable of information processing incorporated into edge computing in future technologies.

The optimized structure of composited materials decides the electrochemical performances of supercapacitors. Herein, the NiCo2O4@MnMoO4 particles with novel and functional structure were synthesized by two-step hydrothermal method process in this work, in which nickel foam (Ni foam) was employed as substrate. In the experiment process, the NiCo2O4 particles were prepared on the Ni foam and then the NiCo2O4@MnMoO4 particles were prepared on the NiCo2O4. According to the electrochemical tests, both the NiCo2O4 and NiCo2O4@MnMoO4 micro-particles prepared in this work have superior electrochemical performances including higher specific capacitances than most of the other NiCo2O4 and NiCo2O4@MnMoO4 researches. At the scan rate of 5 mA·cm−2, the area specific capacitance of the NiCo2O4 electrode is 4.73 F cm−2 (equivalent to 1152.4 F·g−1 mass specific capacitance), while that of the NiCo2O4@MnMoO4 electrode is 16.40 F cm−2 (equivalent to 2603.9 F·g−1 mass specific capacitance). The cycling performance of the NiCo2O4 and NiCo2O4@MnMoO4 at the current density of 5 mA·cm−2 were measured. After 3000 discharge–charge cycles, the specific capacitance of the NiCo2O4 micro-particles remains 112.2% of its initial value, and the NiCo2O4@MnMoO4 micro-particles remains 92.1%. The asymmetric supercapacitor is assembled by the NiCo2O4@MnMoO4 compounds and activated carbon (AC), which show high energy density of 44.16 Wh/kg at power density of 0.8 kW/kg. The results show that the NiCo2O4@MnMoO4 composite is an excellent candidate for electrode materials of energy storage devices.

Nonlinear dynamical systems serving reservoir computing enrich the physical implementation of computing systems. A method for building physical reservoirs from electrochemical reactions is provided, and the potential of chemical dynamics as computing resources is shown. The essence of signal processing in such systems includes various degrees of ionic currents which pass through the solution as well as the electrochemical current detected based on a multiway data acquisition system to achieve switchable and parallel testing. The results show that they have respective advantages in periodic signals and temporal dynamic signals. Polyoxometalate molecule in the solution increases the diversity of the response current and thus improves their abilities to predict periodic signals. Conversely, distilled water exhibits great computing power in solving a second-order nonlinear problem. It is expected that these results will lead to further exploration of ionic conductance as a nonlinear dynamical system and provide more support for novel devices as computing resources.

The potential of nonlinear dynamical systems serving as reservoirs has attracted much attention for the physical realization of reservoir computing (RC). Here, we propose a hardware system working as a reservoir with one simple form of nonlinearity that reflects the intrinsic characteristics of the materials. We show that insufficient dynamics in such physical systems can perform like complex dynamical systems with the assistance of external controls. Based on the idea of spatial multiplexing, this dynamical system is studied under two frameworks. The correlation between structural adjustments of the reservoir and system performance in processing various types of task is proposed. Our results are expected to enable the development of material-based devices for RC.

For a double-sided bow-tie structure printed on dielectric substrate, the bottom arm may serve as ground plane for strip line printed on the upper side of substrate to feed the top arm. It is demonstrated that the feed strip line can perform an impedance transformation to match the 50Ω feed line in the FCC allocated UWB frequency band if the truncation of the bottom arm is properly designed. A UWB bow-tie antenna is designed and tested, which demonstrates an operation frequency bandwidth from 3.1 GHz to 10.6 GHz for −10dB return loss.

Phase shifter with moveable dielectric wedge plate sandwiching the strip line in a tri-plate transmission line structure is proposed and designed for 3G basestation antenna. Numerical simulations indicate that phase-shift unit with saw-tooth shaped wedge dielectric may provide low return loss and insertion loss. The performance of the proposed wedge dielectric phase shifter is further demonstrated by a four-element 3G linear array. Return loss below −17dB at 3G frequency bands and beam tilting in the vertical plane of the base station antenna in a range of 0.2° to 12 ° can be obtained.

In this paper, a statistical analysis of the peak-to- average power ratio (PAPR) of Polynomial cancellation coded OFDM (PCC-OFDM) signals is presented. PCC-OFDM has the good performance of compressing intercarrier interference (ICI) at the cost of high PAPR. The most PAPR analysis assume the subcarriers to be identically and independently distributed (i.i.d). However, the correlation between adjacent pairwise subcarriers of PCC-OFDM causes the assumption not valid. The adjacent partial transmit sequence (PTS) with parameter constraints can be used to reduce the PAPR of PCC-OFDM. The simulation results show that the theoretic analysis is very close to experimental results. The PAPR of PCC-OFDM signals with 128 subcarriers exhibit near 2dB higher than the same type normal OFDM. PTS based method proposed in this paper can reduce the PAPR of PCC-OFDM to the normal complex-value OFDM level while keeping PCC relation.