改进人工蜂群算法在数字图像相关中的应用

针对人工蜂群算法存在的收敛速度较慢,易陷入局部最优解的问题,提出一种改进的人工蜂群优化算法,并应用于数字图像相关的整像素位移搜索中。该算法借助相关度值的变化来动态调整跟随蜂的搜索步长,平衡其全局和局部的搜索能力;侦察蜂利用遗传算法的交叉运算产生新解,改善全局搜索能力。实验结果表明,改进的算法能有效地提高收敛速度,改善整像素位移搜索的性能。     

Analysis of adjacent channel interference using distribution function for V2X communication systems in the 5.9‐GHz band for ITS

Many use cases have been presented on providing convenience and safety for vehicles employing wireless access in vehicular environments and long‐term evolution communication technologies. As the 70‐MHz bandwidth in the 5.9‐GHz band is allocated as an intelligent transportation system (ITS) service, there exists the issue that vehicular communication systems should not interfere with each other during their usage. Numerous studies have been conducted on adjacent interfering channels, but there is insufficient research on vehicular communication systems in the ITS band. In this paper, we analyze the interference channel performance between communication systems using distribution functions. Two types of scenarios comprising adjacent channel interference are defined. In each scenario, a combination of an aggressor and victim network is categorized into four test cases. The minimum requirements and conditions to meet a 10% packet error rate are analyzed in terms of outage probability, packet error rate, and throughput for different transmission rates. This paper presents an adjacent channel interference ratio and communication coverage to obtain a satisfactory performance.     

UV‐Curable Silver Electrode for Screen‐Printed Thermoelectric Generator

Fabricating thermoelectric generators (TEGs) using the screen‐printing process has advantages, including mass production, device scalability, and system applicability. However, the thick film formed through the process typically has low film density, and reduced performance, because of the presence of pores in the film created by the vaporization of the resin during high‐temperature annealing. During the soldering process used for thermoelectric module fabrication, the printed solder infiltrates into the screen‐printed electrodes through the micropores in the electrodes, causing cracks of the electrode film and an increase in resistivity. In this paper, an ultraviolet radiation (UV)‐curable process for screen‐printed electrodes is reported. The paste for the electrodes is synthesized by mixing Ag flakes that can be cured at low temperature with a UV resin. Scanning electron microscope images show that the UV‐curing process significantly reduces pores and thereby results in a smooth‐surfaced electrode layer. The film density after crystallization is also enhanced. TEGs composed of 72 couples with UV‐curable Ag electrodes generate a high power density of ≈6.69 mW cm^?2 at a temperature difference of 25 °C; the device resistance is ≈0.75 Ω, and the figure of merit of the device is recorded to be 0.57, which is the highest among the printed TEGs.     

Precious‐Metal‐Free Electrocatalysts for Activation of Hydrogen Evolution with Nonmetallic Electron Donor: Chemical Composition Controllable Phosphorous Doped Vanadium Carbide MXene

The insufficient strategies to improve electronic transport, the poor intrinsic chemical activities, and limited active site densities are all factors inhibiting MXenes from their electrocatalytic applications in terms of hydrogen production. Herein, these limitations are overcome by tunable interfacial chemical doping with a nonmetallic electron donor, i.e., phosphorization through simple heat‐treatment with triphenyl phosphine (TPP) as a phosphorous source in 2D vanadium carbide MXene. Through this process, substitution, and/or doping of phosphorous occurs at the basal plane with controllable chemical compositions (3.83–4.84 at%). Density functional theory (DFT) calculations demonstrate that the P? C bonding shows the lowest surface formation energy (ΔG_Surf) of 0.027 eV Å^?2 and Gibbs free energy (ΔG_H) of –0.02 eV, whereas others such as P‐oxide and P? V (phosphide) show highly positive ΔG_H. The P3–V₂CT_x treated at 500 °C shows the highest concentration of P? C bonds, and exhibits the lowest onset overpotential of –28 mV, Tafel slope of 74 mV dec^?1, and the smallest overpotential of ‐163 mV at 10 mA cm^?2 in 0.5 m H₂SO₄. The first strategy for electrocatalytically accelerating hydrogen evolution activity of V₂CT_x MXene by simple interfacial doping will open the possibility of manipulating the catalytic performance of various MXenes.     

Analysis of a Parasitic‐Diode‐Triggered Electrostatic Discharge Protection Circuit for 12 V Applications

In this paper, an electrostatic discharge (ESD) protection circuit is designed for use as a 12 V power clamp by using a parasitic‐diode‐triggered silicon controlled rectifier. The breakdown voltage and trigger voltage (V_t) of the proposed ESD protection circuit are improved by varying the length between the n‐well and the p‐well, and by adding n+/p+ floating regions. Moreover, the holding voltage (V_h) is improved by using segmented technology. The proposed circuit was fabricated using a 0.18‐μm bipolar‐CMOS‐DMOS process with a width of 100 μm. The electrical characteristics and robustness of the proposed ESD circuit were analyzed using transmission line pulse measurements and an ESD pulse generator. The electrical characteristics of the proposed circuit were also analyzed at high temperature (300 K to 500 K) to verify thermal performance. After optimization, the V_t of the proposed circuit increased from 14 V to 27.8 V, and V_h increased from 5.3 V to 13.6 V. The proposed circuit exhibited good robustness characteristics, enduring human‐body‐model surges at 7.4 kV and machine‐model surges at 450 V.     

网络病毒危害与攻防技术分析

网络病毒威胁威胁着每个网络用户,网络黑客可以通过传播病毒获取用户隐私,窃取用户财产.要给网络用户安全的使用环境,就要对网络病毒进行合理防御与查杀.这就需要对网络病毒生成的原理,网络病毒的特征有所了解,有的放矢采取合理技术手段加以防御与清除.本文就网络病毒的特性进行了分析,针对特性就如何防御提出了可行性的建议.     

A review:Photonics devices,architectures,and algorithms for optical neural computing

The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to the fascinating advantages such as high speed,wide bandwidth,and massive parallelism.Here,we offer a review on the optical neural computing in our research groups at the device and system levels.The photonics neuron and photonics synapse plasticity are presented.In addition,we introduce several optical neural computing architectures and algorithms including photonic spiking neural network,photonic convolutional neural network,photonic matrix computation,photonic reservoir computing,and photonic reinforcement learning.Finally,we summarize the major challenges faced by photonic neuromorphic computing,and propose promising solutions and perspectives.     

Crumple Durable Ultraflexible Organic Solar Cells with an Excellent Power-per-Weight Performance

Ultraflexible and ultra-lightweight organic solar cells (OSCs) have attracted great attention in terms of power supply in wearable electronic systems. Here, ultrathin and ultra-lightweight OSCs, with a total thickness of less than 3 µm, with excellent mechanical properties in terms of their flexibility and ability to be stretched are demonstrated. A stabilized power conversion efficiency (PCE) of 15.5% and unprecedented power-per-weight of 32.07 W g⁻¹ at a weight of 4.83 g m⁻² is achieved, which represents one of the best-performing OSCs based on ultrathin foils substrate reported to date. The ternary strategy introduces the third component of amorphous conformation of the PC₇₁BM molecule, which can slightly reduce crystallization and aggregates without decreasing the electron mobility, thereby reducing rigidity and brittleness of the active layer. The increase in the ductility of the active layer significantly improves the mechanical flexibility of the device, resulting in over 90% retention in the PCE after 200 stretching–compression cycles. In addition, the ternary device exhibits excellent stability when stored in a N₂-filled glove box, resulting in the PCE retaining over 95% of its initial efficiency even after 1000 h. This ultraflexible and ultra-lightweight photovoltaic foils constitute a major step toward the integration of power supply into malleable electronic textiles.     

Dopant-Free Hole Transport Materials Based on a Large Conjugated Electron-Deficient Core for Efficient Perovskite Solar Cells

Hole transport materials (HTMs) play a significant role in device efficiencies and long-term stabilities of perovskite solar cells (PSCs). In this work, two simple dopant-free HTMs are designed with a large conjugated electron-deficient core. On the one hand, a large coplanar backbone endows enhanced π–π stacking and reduced hole hopping distance. On the other hand, the incorporation of electron-deficient unit can easily tune the energy levels as well as increase hole mobilities. Combining these two advantages together, 12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro[1,2,5]thiadiazole[3,4-e]thieno[2″,3″:4,5]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole is chosen as the large electron-deficient core to construct two novel dopant-free HTMs, Y6-T and Y-T. Both Y6-T and Y-T behave suitable highest occupied molecular orbital levels, good hole mobilities, as well as strong hydrophobicities. After careful device optimization with a passivation agent, Y-T delivers an impressive power conversion efficiency of 20.29%, which is higher than that of Y6-T (18.82%) and doped spiro-OMeTAD (19.24%). Moreover, PSCs based on Y6-T and Y-T show much better long-term stabilities than spiro-OMeTAD due to the intrinsic hydrophobicity. Therefore, this work provides a promising candidate as well as a useful design strategy for exploring dopant-free HTMs, which may pave the way for the commercialization of PSCs.     

空间光通信APD接收机下LDPC码译码方法及性能分析

准循环-低密度奇偶校验(QC-LDPC)码具有优异的性能,但在译码时需根据具体的信道模型修正对应的译码算法。本文分析了QC-LDPC码在空间光通信中的雪崩光电二极管(APD)接收机下的译码方法及译码性能,提出了在APD接收机信道下计算译码初始化所需的对数似然比(LLR)的方法。仿真结果表明,对APD接收机信道下的译码进行修正后,基本上不增加额外复杂度情况下,QC-LDPC码在精确的韦伯-高斯(Webb-Gaussian)模型下译码性能优于近似的非对称高斯模型;在信道比较理想的条件下,误码率(BER)为10-6时,韦伯-高斯模型与非对称高斯模型译码性能相比有1dB以上的净编码增益。