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Distributed memory reflects the phenomenon that memory can decay over time. In this paper, we are concerned with the joint effect of distributed memory and maturation delay on spatiotemporal dynamics of the model that illustrates spatial movement of animals. Without maturation delay, distributed memory with weak temporal kernel gives rise to Turing and double Turing bifurcations and there is no Hopf bifurcation. When maturation delay exists, it has been shown that the joint effect of distributed memory and maturation delay can lead to rich dynamics due to the occurrence of double Hopf, Turing–Hopf, codimension 3 and codimension 4 bifurcations. The Wright–Hutchinson equation and its modification are employed to illustrate the theoretical results and maturation delay-induced stability switches, spatially inhomogeneous steady states/periodic solutions and quasi-periodic solution are found. [ABSTRACT FROM AUTHOR]

To break the von Neumann bottleneck, emerging non-volatile memories have gained extensive attention in hardware implementing neuromorphic computing. The device scaling with low operating voltage is of great importance for delivering a high-integrating and energy-efficient neuromorphic system. In this paper, we fabricated sub-10 nm ferroelectric capacitors based on HfZrO (HZO) film with varying HfO and ZrO components. Compared to the conventional HZO capacitors (a constant component of 1:1), the varying component ferroelectric capacitors show similar remnant polarization but a lower coercive electric field (Ec). This enables the partial domain switching processed at a lower pulse amplitude and width, which is essential for emulating typical synaptic features. In the MNIST recognition task, the accuracy of sub-10 nm ferroelectric artificial synapse can approach ∼85.83%. Our findings may provide great potential for developing next-generation neuromorphic computing-based ultra-scaled ferroelectric artificial synapses. [ABSTRACT FROM AUTHOR]

For the optimization design of the thermoelastic structures in transient heat transfer, the commonly used design methods in previous studies which transforms the transient heat transfer into a steady-state heat transfer could result in significant inaccuracy in the analysis and design of the thermoelastic structure. This study presents a topology optimization method for thermoelastic structures under transient thermal loads considering thermal stress constraints to realize the accurate optimization and effective stress control of transient thermoelastic structures. Condensed integrals in the time and space domains are used to approximately represent the maximum temperature and thermal stress. Two optimization models are proposed. One is to minimize the weighted sum of the dimensionless strain energy and the maximum temperature with a material volume constraint, and the other is to minimize the strain energy with constraints on the maximum stress and material volume. The temperature field and elastic responses are obtained by solving the transient thermal conductive equations and thermoelastic equations. The adjoint method is used to derive the sensitivity expressions. Three numerical examples are provided to illustrate the effectiveness and necessity of the proposed method. The results showed that to realize the accurate design of transient thermoelastic structures, it is necessary for the adopted design method to accurately reflect the influence of the transient effects on the structural response, while the method proposed in this paper can achieve this. [ABSTRACT FROM AUTHOR]

The artificial synapses are basic units in the hardware implementation of neuromorphic computing, whose performances should be gradually modulated under external stimuli. The underlying mechanism of the increasing and decreasing device conductance is still unclear in the Hf0.5Zr0.5O2 based synapses. In this study, the Hf0.5Zr0.5O2 capacitors with different stack orders are fabricated in atomic layer deposition, whose ferroelectric properties are investigated by analyzing the capacitanceâ€"voltage and polarization-voltage curves. The enhanced ferroelectricity is found after the rapid thermal annealing treatment for all the TiN/Hf0.5Zr0.5O2/TiN, TiN/HfO2-ZrO2/TiN and TiN/ZrO2-HfO2/TiN devices. In the device with poor ferroelectricity, the conductance gradually decreases under both positive and negative identical pulse schemes, which corresponds to the gradual dissolution process of the conductive filaments established in the initial pulse. For the capacitors with strong ferroelectricity, dual-direction conductance modulation can be observed due to the partial domain switching process, which can emulate the potentiation and depression process of biological synapses. [ABSTRACT FROM AUTHOR]

Reservoir computing (RC) is a low-cost and temporary-signal friendly computational framework, whose hardware implementation is hindered by integrating huge amounts and various kinds of devices. Benefitted from the logic in memory (LIM) capability, the process compatible Hf0.5Zr0.5O2 (HZO)-based ferroelectric field-effect-transistor (FeFET) is a promising candidate for implementing artificial networks. In this letter, a fully FeFETs RC network is proposed. Multiple functions can be achieved in a single device owing to its intrinsic characteristics, and the richness of virtual nodes is largely enhanced through full-connection structures. Impressively, only 44 FeFETs are required to construct a compact RC network with 100 ns operating speed and high accuracy in classification tasks. This paves the way to develop the high energy-efficiency FeFET RC networks. [ABSTRACT FROM AUTHOR]

In this paper, a topology optimization model is proposed for transient heat conduction structure design. In this model, a new performance index, named as the Regional Temperature Control Function (RTCF), was introduced as the objective function for representing the maximum temperature of specific areas during the whole working time, in this way the effect of the transient heat conduction on the topology is considered. An analytical expression is derived for the sensitivity analysis. Numerical examples demonstrate that the optimized topological solutions of the transient heat conduction structure exhibit the remarkable transient effect. That is to say, the optimal topology is closely related to the working time, and the different working time will lead to completely different topology designs for the same problem. Results also indicate that the proposed topology optimization model can exactly reflect the transient effect and achieve satisfactory topological solutions. In addition, compared with the transient thermal compliance as the objective function, the proposed RTCF can gain the design results with the obvious decrease of maximum temperature, which also implicates that the proposed topology optimization model for transient heat conduction structures is highly effective. [ABSTRACT FROM AUTHOR]