Communications engineering最新文献

Intracortical brain-computer interfaces (iBCIs) hold promise for restoring motor, sensory, and cognitive functions, including applications in paralysis treatment and speech decoding. High-density microelectrode arrays (MEAs) provide fine spatial and temporal discrimination of neural activity, but the considerable upsurge in data generation poses challenges for wireless transmission from miniaturized implants due to constraints on power, bandwidth, heat dissipation, and device size. To address these constraints, we propose a two-stage wireless iBCI architecture comprising a transdural galvanic-coupled body channel communication (BCC) link from a free-floating MEA to an intracranial unit, followed by a transcutaneous link to an external unit. This study focuses on the transdural BCC telemetry system, which provides compact, wideband, and energy-efficient data transmission. Phantom tests, and ex vivo experiments using a human cadaveric head specimen validate the system, demonstrating wireless transmission up to 500 Mbps with 20% duty cycling and bit error rates below 10⁻⁵. The system incorporates the send-on-delta encoder (SODA), achieving up to 11.4× data compression and reducing thermal load for meeting the safety guidelines. Safety is further examined using brain-on-a-chip models, which demonstrate that the system does not evoke unintended neural activity, supporting the platform's long-term viability for high-resolution iBCIs.

The growing demand for low-cost, lightweight, and high-efficiency space technologies has driven the search for photovoltaic solutions which minimize material use without sacrificing performance. III-V multijunction solar cells remain the state of the art for space power applications due to their exceptional efficiency and radiation resistance. Among III-V solar cells architectures, Germanium (Ge)-based structure remains widely used; however, their broader deployment is limited by reliance on thick and expensive Ge substrates. Germanium membranes, however, offer a promising path to address these limitations through substrate reuse strategies. This review highlights progress in the development of Ge membrane as a transformative platform for space photovoltaics, with a focus on porous Ge-based lift-off approaches while reusing Ge substrate. These methods enable the fabrication of detachable, monocrystalline Ge membrane through pore etching, epitaxial growth, porous transformation, layer lift-off and substrate reuse, significantly reducing Ge consumption and device weight. Two main fabrication routes for porous Ge formation are discussed: lithography-based dry etching using Ge-On-Nothing approach and electrochemical etching. The fundamentals of pore formation, thermal reorganization of porous, and subsequent III-V epitaxy are reviewed. Key challenges related to process uniformity, detachment scalability, and industrial integration are examined, and potential strategies for scalable manufacturing are outlined.

Reliable prediction of structural vulnerability under complex multiaxial loading remains challenging due to nonlinear load couplings, imbalanced failure-critical samples, and limited model interpretability. Here, we present a mechanics-informed, risk-aware learning framework integrating polynomial-harmonic feature augmentation, Weibull-based risk reweighting, and a unified Degradation Risk Score that combines stress margins and bolt pretension loss. Demonstrated on a bolted steering-knuckle assembly with finite-element-derived multiaxial load-response data, the framework improves multiple linear regression from R² = 0.37 to 0.96 with a 67% reduction in RMSE, while enhancing robustness and sensitivity in high-risk regimes across ensemble and neural network models. SHAP analysis confirms that physically meaningful multiaxial interaction features dominate predictions, revealing critical load paths associated with structural vulnerability. Finally, Bayesian logistic and Weibull calibration provide a route to link Degradation Risk Score to component-level failure probabilities, enabling probabilistic risk assessment and reliability-centred decision-making in practical engineering systems.

Undetected, asymptomatic brain aneurysms are associated with risk of progressive expansion, followed by rupture and hemorrhage, increasing the risk of mortality and morbidity. Imaging techniques to assess the state and stent treatment of aneurysms are beneficial. By Magnetic Particle Imaging (MPI), we were able to resolve with millisecond temporal resolution the location and movement of a tracer bolus in different parts of an artery phantom derived from a patient specific CT data set including a cerebral aneurysm. To assess the success of a flow diverter stent treatment, we compared flow MPI measurements in the artery phantom without a flow diverter stent with images where a stent was inserted. Our results provide valuable information on the capabilities and prospects of MPI of vascular structures and the detection and quantification of flow changes in untreated and treated aneurysms for future in vivo applications.

Formwork for concrete construction remains one of the most resource-intensive, polluting, and constraining components of the construction sector, relying on prefabricated molds that demand extensive material, labor, and on-site preparation. We introduce a self-deploying formwork system based on multistable tubes that transform from a compact configuration to a full-scale structural mold with integrated steel reinforcement. We demonstrate this concept by deploying a steel-reinforced 2.36 m high structure within 14 seconds. We further observed that the polymer shell of the multistable tubes increases the structural strength by a factor of three, significantly enhancing their load-bearing capacity. The demonstrated concept paves the way for the creation of concrete castings with minimal on-site intervention, enabling a scalable pathway toward rapid, low-carbon construction methods.

Radiofrequency front ends for current and next generation (5G and 6G) wireless communication demand acoustic filters that combine wide bandwidth, high power capability, and thermal stability. Existing surface and bulk acoustic wave technologies face inherent trade-offs between electromechanical coupling, lithographic tunability, and robustness. Here, we introduce the bulk acoustic resonator with vertical electrodes (VBAR), a device that combines the advantages of suspended and solidly mounted resonators. VBARs use lithium niobate ridges with sidewall electrodes to excite a shear-horizontal bulk acoustic resonance, providing frequency control through lithography in a configuration that is mechanically anchored to the substrate. Fabricated VBARs exhibit electromechanical coupling coefficients exceeding 30% in the 2-4 GHz range, enabling ladder filters with fractional bandwidths of nearly 20%. While further optimization is necessary to minimize losses, the VBAR concept offers an alternative route toward wideband and robust radiofrequency filters for next-generation wireless systems.

Super-resolution microscopy has become an indispensable core research tool in biology, materials science and medicine, yet existing technologies face an inherent bottleneck where resolution, large field of view (FOV), label-free compatibility and system cost cannot be simultaneously optimized. A miniaturized full-frequency encoded illumination (mini-FEI) chip is presented for high-throughput super-resolution imaging using the spatial frequency shift (SFS) effect. We propose a tunable continuous SFS method for across far-field and near-field illumination modulation, which is achieved through propagating and evanescent waves. The multi-illumination modes are precisely and flexibly modulated by an encoded LED array. The light travels to the sample via a set of prisms, producing super-resolution images with high signal-to-noise ratio (SNR). Mini-FEI super-resolution imaging reaches a resolution of 333 nm ( ~ λ/4NA), while maintaining a large FOV of ~1 mm². The method is validated on label-free samples including USAF Target, Star Target, onion root tip cells, and live COS7 cells, all of which could be successfully reconstructed. Through the introduction of integrated LED arrays for evanescent wave excitation, expensive laser systems can be avoided and the system significantly miniaturized. The mini-FEI super-resolution imaging chip is simple and cost-effective to fabricate, is compatible with commercial microscopes, and thus holds great potential for widespread deployment in scientific and industrial research.