Piezoelectric cantilever beams are commonly utilized to harvest energy from environmental vibrations due to their simple structures. This paper optimizes a single crystal trapezoidal hollow structure piezoelectric cantilever beam vibration energy harvester with a copper substrate to achieve high energy density at a low frequency. Finite element analysis (FEA) is adopted to optimize the size of the copper substrate at first, and the piezoelectric energy harvester (PEH) is further optimized with a trapezoidal hollow structure under the optimal size of the copper substrate. The developed PEH with a trapezoidal hollow structure (L_a = 20 mm, L_b = 15 mm, and L_h = 40 mm), with a copper substrate of 80 mm × 33 mm × 0.2 mm, can obtain the best output performance. Under the condition of 1 g acceleration, the resonance frequency and peak voltage output were 23.29 Hz and 40.4 V, respectively. Compared with the unhollowed PEH, the developed trapezoidal hollow structure PEH can reduce its resonant frequency by 12.18% and increase output voltage by 34.67%, while also supplying a power density of 7.24 mW/cm³. This study verified the feasibility of the optimized design through simulation and experimental comparison.

A cyclometallated phosphorescent iridium-based probe to detect CN^– was prepared through a cyanide alcoholize reaction based on the C^N type main ligand and N^N type ancillary ligand (2-phenyl pyridine and 1,10-phenanthroline-5-carboxaldehyde, respectively). The efficient probe exhibited good sensitivity in response to CN^– in an CH₃CN and H₂O (95/5) mixture within a 1.23 μM detection limit. The response of PL is directly in line with the concentration of CN^– from 0 to 2.0 equiv. The PL investigation of other reactive anions proved the great selectivity to CN^–. Additionally, upon adding 1.0 equiv. of cyanide, the formation of cyanohydrin was correctly elucidated in ¹H NMR, FT-IR, and mass spectra studies. The conspicuous results indicate that the iridium complex has the potential possibility of application in other biosystems related to CN^–.

High temperature gradient and rapid solidification rate in the laser powder bed fusion (LPBF) process could result in the presence of columnar grains, which could cause poor high temperature tensile properties in the as-built LPBF Hastelloy X (HX) alloys. Heat treatment could effectively transform columnar grain into the equiaxed grain. However, carbides also are precipitated during heat treatment, which could lead to the reduction in ductility. In this study, we aimed to investigate the effect of carbide morphology and distribution on high-temperature tensile properties of LPBF HX alloys by using different heat treatment methods (the same dwell temperature, different cooling methods). The carbide morphology and distribution after furnace cooling, air cooling, and water quenching were characterized respectively, and were correlated with the high-temperature tensile properties. Scanning electron microscope (SEM) images for the fracture surface and cross-sectional area analysis found that the high-temperature tensile properties, especially the ductility, were affected by the carbide morphologies along grain boundaries.

Spiking neural networks (SNNs) have emerged as a promising model for energy-efficient, event-driven processing of asynchronous event streams from Dynamic Vision Sensors (DVSs), a class of neuromorphic image sensors with microsecond-level latency and high dynamic range. Nevertheless, challenges persist in optimising training and effectively handling spatio-temporal complexity, which limits their potential for real-time applications on embedded sensing systems such as object tracking and recognition. Targeting this neuromorphic sensing pipeline, this paper proposes the Dynamic Tracking with Event Attention Spiking Network (DTEASN), a novel framework designed to address these challenges by employing a pure SNN architecture, bypassing conventional convolutional neural network (CNN) operations, and reducing GPU resource dependency, while tailoring the processing to DVS signal characteristics (asynchrony, sparsity, and polarity). The model incorporates two innovative, self-developed components: an event-driven multi-scale attention mechanism and a spatio-temporal event convolver, both of which significantly enhance spatio-temporal feature extraction from raw DVS events. An Event-Weighted Spiking Loss (EW-SLoss) is introduced to optimise the learning process by prioritising informative events and improving robustness to sensor noise. Additionally, a lightweight event tracking mechanism and a custom synaptic connection rule are proposed to further improve model efficiency for low-power, edge deployment. The efficacy of DTEASN is demonstrated through empirical results on event-based (DVS) object recognition and tracking benchmarks, where it outperforms conventional methods in accuracy, latency, event throughput (events/s) and spike rate (spikes/s), memory footprint, spike-efficiency (energy proxy), and overall computational efficiency under typical DVS settings. By virtue of its event-aligned, sparse computation, the framework is amenable to highly parallel neuromorphic hardware, supporting on- or near-sensor inference for embedded applications.

Cerebral organoids derived from human induced pluripotent stem cells (iPSCs) have emerged as powerful in vitro models for studying human brain development and neurological disorders. Understanding the electrophysiological properties of these organoids is crucial for evaluating their functional maturity and potential applications. However, the differentiation and maturation of stem cells into cerebral organoids is a long, slow, and error-prone process. Hence, it is vitally crucial to establish a non-invasive method of monitoring the process over a long period of time. In this study, a planar microelectrode array (MEA) with platinum (Pt) black electroplating is designed to monitor the electrophysiological activities and pharmacological responses of cerebral organoids using an external neural signal acquisition system interfaced with the MEA. The planar MEA with Pt black electroplating has a significantly reduced electrode impedance and exhibits a robust capability for the real-time detection of spontaneous neural activities, including extracellular spikes and local field potentials. Distinct electrophysiological signal strengths in cerebral organoids were observed at early and late developmental stages. Further pharmacological stimulations showed that 30 mM KCl would induce a marked increase in spike rate, indicating an enhancement of neuronal depolarization and an elevation of network excitability. This robust response to KCl stimulation in mature networks serves as a reliable indicator of neural maturity in cerebral organoids and underscores the platform’s potential for drug screening applications. This work highlights the integration of MEA technology with cerebral organoids, offering a powerful platform for real-time electrophysiological monitoring. It provides new insights into the functional maturation of neural networks and establishes a reliable system for drug screening and disease modeling, facilitating future research into human brain physiology and pathology.

Nowadays, Mn-doping is considered as a promising dissolution for the heavy usage of toxic lead in CsPbX₃ perovskite material. Interestingly, Mn-doping also introduces an additional photoluminescence band, which is favorable to enrich the emission gamut of this cesium lead halide. Here, a solution spraying strategy was employed for the direct preparation of CsPb_xMn_1−x(Br,Cl)₃ film through MnCl₂ doping in host CsPbBr₃ material. The possible fabrication mechanism of the provided approach and the dependences of material properties on Mn-doping were investigated in detail. As the results shown, Pb was partially substituted by Mn as expected. With the ratio of PbBr₂:MnCl₂ increasing from 3:0 to 1:1, the obtained film separately featured green, cyan, orange-red and pink-red emission, which was caused by the energy transferring process. Moreover, the combining energy of Cs, Pb, and Mn gradually red-shifted resulted from the formation of Cs-Cl, Pb-Cl and Mn-Br coordination bonding as MnCl₂ doping increased. In addition, the weight of short decay lifetime of prepared samples increased with the doping rising, which indicated a better exciton emission and less defect-related transition. The aiming of current work is to provide a new possibility for the facile preparation of Mn-doping CsPbX₃ film material.