基于强化学习的频控阵-多输入多输出雷达发射功率分配方法

当前电磁环境日益复杂多变,新式干扰手段层出不穷,对雷达系统带来了极大的挑战和威胁。该文引入频谱干扰模型并提出了一种在频控阵-多输入多输出(FDA-MIMO)雷达与干扰机动态博弈框架下基于强化学习(RL)的发射功率分配优化方法,使雷达系统能够获得最大的信干噪比(SINR)。在此基础上,构造了频谱干扰模型。其次,雷达和干扰机之间存在一种Stackelberg博弈关系,且将雷达作为领导者,干扰机作为跟随者,建立动态博弈框架下的发射功率分配优化模型。采用深度确定性策略梯度(DDPG)算法,结合功率约束设计了奖赏函数,对雷达发射功率进行实时分配来获得最大的输出SINR。最后,仿真结果表明,在雷达与干扰机博弈的框架下,所提优化算法能够有效地对雷达发射功率进行优化,使雷达具备较好的抗干扰性能。     

新型多通道微波辐射计及大气观测分析

MWP967KV型微波辐射计是国内第一台自主研发的地基多通道微波辐射计,能够接收和精确测量5毫米和13毫米波段大气辐射强度,可以实时反演出从地面到垂直10km上空高分辨率的大气温湿廓线,而且能探测路径气柱上的水汽和液态水积分总量。本文介绍了MWP967KV型微波辐射计的主要功能、工作原理,并与进口辐射计在不同天气条件下的输出数据进行了对比,结果表明该设备具有优良的工作性能。     

Morphological Stabilization by Supramolecular Perfluorophenyl‐C60 Interactions Leading to Efficient and Thermally Stable Organic Photovoltaics

A new PC₆₁BM‐based fullerene, [6,6]‐phenyl‐C₆₁ butyric acid pentafluorophenyl ester (PC₆₁BP^F) is designed and synthesized. This new n‐type material can replace PC₆₁BM to form a P3HT:PC₆₁BP^F binary blend or serve as an additive to form a P3HT:PC₆₁BM:PC₆₁BP^F ternary blend. Supramolecular attraction between the pentafluorophenyl group of PC₆₁BP^F and the C₆₀ cores of PC₆₁BP^F/PC₆₁BM can effectively suppress the PC₆₁BP^F/PC₆₁BM materials from severe aggregation. By doping only 8.3 wt% PC₆₁BP^F, device PC₆₁BP^F651 exhibits a PCE of 3.88% and decreases slightly to 3.68% after heating for 25 h, preserving 95% of its original value. When PC₆₁BP with non‐fluorinated phenyl group is used to substitute PC₆₁BP^F, the stabilizing ability disappears completely. The efficiencies of PC₆₁BP651 and PC₆₁BP321 devices significantly decay to 0.44% and 0.11%, respectively, after 25 h isothermal heating. Most significantly, this strategy is demonstrated to be effective for a blend system incorporating a low band‐gap polymer. By adding only 10 wt% PC₆₁BP^F, the PDTBCDTB: PC₇₁BM‐based device exhibits thermally stable morphology and device characteristics. These findings demonstrate that smart utilization of supramolecular interactions is an effective and practical strategy to control morphological evolution.     

Triboelectric Nanogenerator as an Active UV Photodetector

Self‐powered nanosensors and nanosystems have attracted significant attention in the past decades and have gradually become the most desirable and promising prototype for environmental protection/detection because no battery is needed to power the device. Therefore, in this paper a design is proposed for a self‐powered photodetector based on triboelectric nanogenerator (TENG) configuration. 3D dendritic TiO₂ nanostructures are synthesized as the built‐in UV photodetector as well as the contact material of the TENG. The cost‐effective, robust, and easily fabricated TENG‐based photodetector presents superior photoresponse characteristics, which include an excellent responsivity over 280 A W^?1, rapid rise time (18 ms) and decay time (31 ms), and a wide detection range of light intensity from 20 μW cm^?2 to 7 mW cm^?2. In the last part of the paper, a stand‐alone and self‐powered environmental sensing device is developed by applying poly(methyl methacrylate) (PMMA) substrates and springs to assemble the TENG‐based photodetector. These results indicate that the new prototype sensing device based on the TENG configuration shows great potential as a self‐powered photodetector.     

Solution‐Processed Small‐Molecule Bulk Heterojunction Ambipolar Transistors

Solution‐processed small‐molecule bulk heterojunction (BHJ) ambipolar organic thin‐film transistors are fabricated based on a combination of [2‐phenylbenzo[d,d']thieno[3,2‐b;4,5‐b']dithiophene (P‐BTDT) : 2‐(4‐n‐octylphenyl)benzo[d,d ']thieno[3,2‐b;4,5‐b']dithiophene (OP‐BTDT)] and C₆₀. Treating high electrical performance vacuum‐deposited P‐BTDT organic semiconductors with a newly developed solution‐processed organic semiconductor material, OP‐BTDT, in an optimized ratio yields a solution‐processed p‐channel organic semiconductor blend with carrier mobility as high as 0.65 cm² V^?1 s^?1. An optimized blending of P‐BTDT:OP‐BTDT with the n‐channel semiconductor, C₆₀, results in a BHJ ambipolar transistor with balanced carrier mobilities for holes and electrons of 0.03 and 0.02 cm² V^?1 s^?1, respectively. Furthermore, a complementary‐like inverter composed of two ambipolar thin‐film transistors is demonstrated, which achieves a gain of 115.     

Mesostructured Arrays of Nanometer‐spaced Gold Nanoparticles for Ultrahigh Number Density of SERS Hot Spots

A novel one‐trough synthesis via an air‐water interface is demonstrated to provide hexagonally packed arrays of densely spaced metallic nanoparticles (NPs). In the synthesis, a mesostructured polyoxometalate (POM)‐silicatropic template (PSS) is first self‐assembled at the air‐water interface; upon UV irradiation, anion exchange cycles enable the free‐floating PSS film to continuously uptake gold precursors from the solution subphase for diffusion‐controlled and POM‐site‐directed photoreduction inside the silica channels. NPs ≈ 2 nm can hence be homogeneously formed inside the silica‐surfactant channels until saturation. As revealed via X‐ray diffraction, small‐angle X‐ray scattering (SAXS), grazing incidence SAXS, and transmission electron microscopy, the Au NPs directed by the PSS template are arrayed into a 2D hexagonal lattice with inter‐channel spacing of 3.2 nm and a mean along‐channel NP spacing of 2.8 nm. This corresponds to an ultra‐high number density (≈10¹⁹ NPs cm^?3) of narrowly spaced Au NPs in the Au‐NP@PSS composite, leading to 3D densely deployed hot‐spots along and across the mesostructured POM‐silica channels for surface‐enhanced Raman scattering (SERS). Consequently, the Au‐NP@PSS composite exhibits prominent SERS with 4‐mercaptobenzoic acid (4‐MBA) adsorbed onto Au NPs. The best 4‐MBA detection limit is 5 nm , with corresponding SERS enhancement factors above 10⁸.     

Hierarchical Graphene–Carbon Fiber Composite Paper as a Flexible Lateral Heat Spreader

As a low dimensional crystal, graphene attracts great attention as heat dissipation material due to its unique thermal transfer property exceeding the limit of bulk graphite. In this contribution, flexible graphene–carbon fiber composite paper is fabricated by depositing graphene oxide into the carbon fiber precursor followed by carbonization. In this full‐carbon architecture, scaffold of one‐dimensional carbon fiber is employed as the structural component to reinforce the mechanical strength, while the hierarchically arranged two‐dimensional graphene in the framework provides a convenient pathway for in‐plane acoustic phonon transmission. The as‐obtained hierarchical carbon/carbon composite paper possesses ultra‐high in‐plane thermal conductivity of 977 W m^?1 K^?1 and favorable tensile strength of 15.3 MPa. The combined mechanical and thermal performances make the material highly desirable as lateral heat spreader for next‐generation commercial portable electronics.     

基于模式识别轮轴识别器的改良与应用

轮轴识别器模式识别的改良与应用,适用于高速公路计重收费中,采用模式识别技术,在统计分析大量货车计重数据的基础上,结合现有车型建立模型数据库,根据计重仪表提供的货车轴间距、轴重、车长等数据,分析判断得出货车轴型。克服了传统的轮轴识别器在使用过程中由于外界的泥沙、油污、冻冰现象导致的识别率下降,维修率逐年提高,通过软件技术和单片机电子技术成功解决了这一难题。     

一种采用多个渐变反型电荷层优化电场的LDMOST

A lateral double-diffused metal-oxide-semiconductor field effect transistor （LDMOST） with multiple n-regions in the p-substrate is investigated in detail. Because of the decrescent n-regions, the electric field distribu- tion is higher and more uniform, and the breakdown voltage of the new structure is increased by 95%, in comparison with that of a conventional counterpart without substrate n-regions. Based on the trade-off between the breakdown voltage and the on-resistance, the optimal number of n-regions and the other key parameters are achieved. Furthermore, sensitivity research shows that the breakdown voltage is relatively sensitive to the drift region doping and the n-regions＇ lengths.     

石墨烯在电子器件研究中的应用

石墨烯是近年来逐步发展起来的新型电子材料,具有导电性好、电子迁移率高、比表面积大、导热率高、弹性好等优点,石墨烯的开发和应用已成为纳米材料、生物、化学以及电子信息等多个领域的研究热点。围绕近年来石墨烯在电子器件中的应用研究,本文主要对其在生化传感器、高速器件、太阳能电池、储能器件、柔性器件5个热点方向中的部分研究成果进行综述。