一种面向序列密码的混合粒度并行运算单元

针对可重构密码处理器对于不同域上的序列密码算法兼容性差、实现性能低的问题,该文分析了序列密码算法的多级并行性并提出了一种反馈移位寄存器(FSR)的预抽取更新模型。进而基于该模型设计了面向密码阵列架构的可重构反馈移位寄存器运算单元(RFAU),兼容不同有限域上序列密码算法的同时,采取并行抽取和流水处理策略开发了序列密码算法的反馈移位寄存器级并行性,从而有效提升了粗粒度可重构阵列(CGRA)平台上序列密码算法的处理性能。实验结果表明与其他可重构处理器相比,对于有限域(GF)(2)上的序列密码算法,RFAU带来的性能提升为23%～186%;对于GF(2u)域上的序列密码算法,性能提升达约66%～79%,且面积效率提升约64%～91%。     

Lithiation-Induced Defect Engineering to Promote Oxygen Evolution Reaction

Exploring efficient electrocatalysts for oxygen evolution reaction (OER) is an urgent need to advance the development of sustainable energy conversion. Though defect engineering is considered an effective strategy to regulate catalyst activity for enhanced OER performance, the controllable synthesis of defective oxides electrocatalysts remains challenging. Here, oxygen defects are introduced into NiCo₂O₄ nanorods by an electrochemical lithiation strategy. By tuning in situ lithiation potentials, the concentration of oxygen defects and the corresponding catalytic activity can be feasibly regulated. In addition, the relationship between the changes in the defect density and electronic structure and the lithiation cut-off voltages is revealed. The results show that NiCo₂O₄ nanorods undertook intercalation and two-step conversion reaction, in which the lithiation-induced conversion reaction gives rise to a CoO@NiO-based structure with higher defect density and lower oxidation states. As a result, the defective CoO@NiO-based catalyst exhibits exceptional OER activity with an overpotential of 270 mV at 10 mA cm⁻², which is about 74 mV below the pristine nanomaterials. This research proposes a novel strategy to explore high-performance catalysts with structural stability and defect control.     

Direct Freeform Laser Fabrication of 3D Conformable Electronics

3D conformable electronic devices on freeform surfaces show superior performance to the conventional, planar ones. They represent a trend of future electronics and have witnessed exponential growth in various applications. However, their potential is largely limited by a lack of sophisticated fabrication techniques. To tackle this challenge, a new direct freeform laser (DFL) fabrication method enabled by a 5-axis laser processing platform for directly fabricating 3D conformable electronics on targeted arbitrary surfaces is reported. Accordingly, representative laser-induced graphene (LIG), metals, and metal oxides are successfully fabricated as high-performance sensing and electrode materials from different material precursors on various types of substrates for applications in temperature/light/gas sensing, energy storage, and printed circuit board for circuit. Last but not the least, to demonstrate an application in smart homes, LIG-based conformable strain sensors are fabricated and distributed in designated locations of an artificial tree. The distributed sensors have the capability of monitoring the wind speed and direction with the assistance of well-trained machine-learning models. This novel process will pave a new and general route to fabricating 3D conformable electronic devices, thus creating new opportunities in robotics, biomedical sensing, structural health, environmental monitoring, and Internet of Things applications.     

Vapor Phase Growth of Centimeter-Sized Band Gap Engineered Cesium Lead Halide Perovskite Single-Crystal Thin Films with Color-tunable Stimulated Emission

Single crystal metal halide perovskites thin films are considered to be a promising optical, optoelectronic materials with extraordinary performance due to their low defect densities. However, it is still difficult to achieve large-scale perovskite single-crystal thin films (SCTFs) with tunable bandgap by vapor-phase deposition method. Herein, the synthesis of CsPbCl_3(1–x)Br_3x SCTFs with centimeter size (1 cm × 1 cm) via vapor-phase deposition is reported. The Br composition of CsPbCl_3(1–x)Br_3x SCTFs can be gradually tuned from x = 0 to x = 1, leading the corresponding bandgap to change from 2.29 to 2.91 eV. Additionally, an low-threshold (≈23.9 µJ cm⁻²) amplified spontaneous emission is achieved based on CsPbCl_3(1–x)Br_3x SCTFs at room temperature, and the wavelength is tuned from 432 to 547 nm by varying the Cl/Br ratio. Importantly, the high-quality CsPbCl_3(1–x)Br_3x SCTFs are ideal optical gain medium with high gain up to 1369.8 ± 101.2 cm⁻¹. This study not only provides a versatile method to fabricate high quality CsPbCl_3(1–x)Br_3x SCTFs with different Cl/Br ratio, but also paves the way for further research of color-tunable perovskite lasing.     

Recent Progress of Bismuth Effect on All-Inorganic Lead-Free Metal Halide Derivatives: Crystals Structure,Luminescence Properties,and Applications

Bismuth (Bi³⁺)-included lead-free metal halide (LFMH) materials attract much attention in lighting, display, photodetectors, X-ray detectors, and photovoltaic fields, due to the tunable luminescence and optoelectronic performance in response to crystal and electronic structure, morphology, and particle sizes. This review summarizes Bi³⁺-included LFMH materials about their preparation approach, crystal and electronic structure properties, luminescence performance, and emerging applications. Notably, Bi³⁺ ions not only can act as framework cation to construct stable LFMH structure, but can also incorporate into LFMH materials as activators or sensitizers to generate remarkable luminescence tuning and band engineering. The Bi³⁺ effect on the luminescence and optoelectronic properties of LFMH materials, including, promotion of exciton localization, enhancement of light absorption in near-ultraviolet region, action as sensitizer ions to transfer energy to rare earth or transition metal ions and emission of highly-efficient light is systematically summarized. The proposed structure-luminescence relationship offers guidance for the optimization of current Bi³⁺-included LFMH materials and the exploitation of new LFMH derivatives.     

一种GHz高频应用的低失调高速CMOS动态比较器

提出了一种由改进的前置差分运算放大器和差分式锁存器构成的高频、高速、低失调电压的动态比较器。前置预差分放大器采用PMOS交叉互连的负载结构,提升差模增益,进而减小输入失调。后置输出级锁存器采用差分双尾电流源抑制共模噪声,改善输出级失调,并加速比较过程。采用一个时钟控制的开关晶体管替代传统复位模块,优化版图面积,在锁存器中构建正反馈回路,加速了比较信号的复位和输出建立过程。采用65 nm/1.2 V标准CMOS工艺完成电路设计,结合Cadence Spectre工艺角和蒙特卡洛仿真分析对该动态比较器的延时、失调电压和功耗特性进行评估。结果表明,在1.2 V电源电压和1 GHz采样时钟控制下,平均功耗为117.1 μW;最差SS工艺角对应的最大输出延迟仅为153.4 ps;1 000次蒙特卡罗仿真求得的平均失调电压低至1.53 mV。与其他比较器相比,该动态比较器的电压失调和高速延时等参数有明显优势。     

时变信道下线性网络分批稀疏码秩分布研究

作为一种应用于多跳网络的低复杂度两步式编码技术,分批稀疏（batched sparse,BATS）码的传输性能与传输矩阵的秩分布直接相关。现有文献在假设各链路丢包率均为常数的前提下,研究了分批稀疏码在纠删信道下的秩分布。然而,在一些场景（如工业互联网）,大量的移动节点部署在整个网络中,可能导致节点之间的信道变成时变信道,即链路上的丢包率随时间变化而变化。因此在假定网络中各节点之间链路丢包率随机变化的场景下,研究了随机线性网络编码（random linear network coding, RLNC）和系统重编码作为内码编码方案时,分批稀疏码传输矩阵的秩分布,推导了链路丢包率服从有限区间正态分布情况下归一化秩期望的闭合解,并通过蒙特卡洛仿真验证了该闭合解的正确性。