34μm孔径GaAs偶极子光电导天线辐射特性仿真研究

光电导天线的辐射特性仿真是设计和制造光电导天线的重要依据。将蒙特卡洛经验公式修正的GaAs迁移率随电场强度的变化关系引入德鲁德-洛伦兹模型,分析了光电导天线载流子输运情况。又将德鲁德-洛伦兹模型计算的光生载流子密度与时域有限差分方法相结合,得到34 m孔径GaAs偶极子光电导天线的时域、频域及三维辐射特性。辐射峰值为0.8 THz,频谱宽度大于1 THz,与太赫兹时域光谱系统实际测量得到的数据吻合。结果表明:仿真方法正确可行,能够为设计和制造高增益、宽频带的太赫兹光电导天线提供参考依据。     

RTD/HEMT串联型RTT的设计与研制

依据RTD/HEMT串联型RTT的概念,设计了RTD/HEMT单片集成材料结构,该结构采用分子束外延技术生长.采用湿法化学腐蚀、金属剥离、台面隔离和空气桥互连技术,研制了RTD/HEMT串联型RTT,并对RTT及RTT中RTD和HEMT的直流特性进行了测试.测试结果表明:在室温下,器件具有明显的栅控负阻特性,正接型RTT的最大峰谷电流之比在2.2左右,反接型RTT的最大峰谷电流之比在4.6左右.实验为RTD/HEMT串联型RTT性能的优化和RTD/HEMT单片集成电路的研制奠定了基础.     

单次可编程金属-分子-金属器件

提出了一种单次可编程的金属-分子-金属器件. 该器件利用一种经过改良的Rotaxane LB膜作为功能层,可以和应用于场编程门阵列电路中的无机反熔丝器件相比拟,将在有机可编程电路和容错电路等方面有较广泛的应用. 所有的加工工艺都是低温工艺,使得该器件可以和其他有机器件集成. 电学测试表明该器件有良好的单次编程能力,其击穿电压为2.2V,关态电阻为15kΩ,而开态电阻为54Ω. 据分析,这一特性是由非对称的电极结构和金属原子在高电场作用下穿透了分子薄膜所造成的.     

A Reliable All-2D Materials Artificial Synapse for High Energy-Efficient Neuromorphic Computing

High-performance artificial synaptic devices are indispensable for developing neuromorphic computing systems with high energy efficiency. However, the reliability and variability issues of existing devices such as nonlinear and asymmetric weight update are the major hurdles in their practical applications for energy-efficient neuromorphic computing. Here, a two-terminal floating-gate memory (2TFGM) based artificial synapse built from all-2D van der Waals materials is reported. The 2TFGM synaptic device exhibits excellent linear and symmetric weight update characteristics with high reliability and tunability. In particular, the high linearity and symmetric synaptic weight realized by simple programming with identical pulses can eliminate the additional latency and power consumption caused by the peripheral circuit design and achieve an ultralow energy consumption for the synapses in the neural network implementation. A large number of states up to ≈3000, high switching speed of 40 ns and low energy consumption of 18 fJ for a single pulse have been demonstrated experimentally. A high classification accuracy up to 97.7% (close to the software baseline of 98%) has been achieved in the Modified National Institute of Standards and Technology (MNIST) simulations based on the experimental data. These results demonstrate the potential of all-2D 2TFGM for high-speed and low-power neuromorphic computing.     

Microfluidic 3D Printing Responsive Scaffolds with Biomimetic Enrichment Channels for Bone Regeneration

Tissue-engineered scaffolds have been extensively explored for treating bone defects; however, slow and insufficient vascularization throughout the scaffolds remains a key challenge for further application. Herein, a versatile microfluidic 3D printing strategy to fabricate black phosphorus (BP) incorporated fibrous scaffolds with photothermal responsive channels for improving vascularization and bone regeneration is proposed. The thermal channeled scaffolds display reversible shrinkage and swelling behavior controlled by near-infrared irradiation, which facilitates the penetration of suspended cells into the scaffold channels and promotes the prevascularization. Furthermore, the embedded BP nanosheets exhibit intrinsic properties for in situ biomineralization and improve in vitro cell proliferation and osteogenic differentiation. Following transplantation in vivo, these channels also promote host vessel infiltration deep into the scaffolds and effectively accelerate the healing process of bone defects. Thus, it is believed that these near-infrared responsive channeled scaffolds are promising candidates for tissue/vascular ingrowth in diverse tissue engineering applications.     

Cucurbiturils-Mediated Noble Metal Nanoparticles for Applications in Sensing,SERS, Theranostics,and Catalysis

Noble metal nanoparticles (NMNPs), which spring up like mushrooms, are gaining momentum owing to their unique physicochemical characteristics. Cucurbiturils, a class of synthetic macrocycles with intriguing and peculiar host–guest properties, have stimulated tremendous research interest in recent years. The marriage of NMNPs with cucurbiturils is expected to integrate and enhance the excellent characteristics of both components, e.g., precisely controlled particle size, stability, assembly, surface functionality, biocompatibility, tunable optical properties, and high catalytic activities. This review systematically outlines the recent progress on the fabricating strategies and important applications of cucurbiturils-mediated NMNPs in sensing, surface-enhanced Raman scattering, theranostics, and catalysis. A brief outlook on the future development of cucurbiturils-mediated NMNPs is also presented.     

共振隧穿二极管的设计、研制和特性分析

用分子束外延技术在半绝缘GaAs衬底上生长制备了不同结构的AlAs/GaAs/InGaAs两垒一阱RTD单管.经过材料生长设计和工艺的改进,测得室温下器件的最高PVCR为2.4,峰值电流密度达到36.8kA/cm2.进行直流参数测试,得到RTD的I-V特性曲线,对量子阱宽度和帽层厚度对I-V特性的影响进行了分析.     

基于压电效应的振荡水柱发电系统CFD分析

"透明海洋"开发需要为远洋检测传感器提供可持续电源,基于压电效应的振荡水柱发电原理是采集波能驱动压电功能材料形变实现能量转换,系统结构简单,稳定性好。基于线性波浪理论,建立振荡水柱(OWC)二维数值波浪水槽。流体动力学(CFD)分析结果表明,造波稳定,波浪在气室内形成的空气压强在时域上呈现一定周期性,经数据处理拟合为正弦曲线。应用ANSYS软件系统的参数化设计语言(APDL)功能开发空气驱动压电材料形变输出能量的仿真模型,分析产生电压变化特性。     

红外焦平面器件脉冲驱动电路的小型化设计

代表着红外器件发展的主流方向的红外焦平面器件,其正常工作时需要驱动脉冲信号多达十几路,为了使红外焦平面阵列处于最佳工作状态,就必须设计出相应的驱动电路.提出了一种红外焦平面器件驱动电路的设计方法.该电路具有体积小、功耗低及灵活性好等特点,为驱动电路以及成像系统的小型化提供了良好的技术基础.     

单相光伏并网逆变器无差拍控制的研究与仿真

光伏并网逆变器是光伏发电系统的主要部件,为了达到更好的效率输出更高质量的电能,对逆变器电流进行快速有效的控制尤为关键。该文简单介绍了当前光伏并网逆变器的几种常用控制方法及其基本思想,分析了并网逆变器的工作原理和无差拍控制方法的原理,给出了逆变器脉冲宽度的计算和参考电流的获取方法,通过MATLAB/Simulink软件仿真表明,无差拍控制在单相光伏并网逆变器控制中动态响应特性好,控制方便,电流跟踪电网电压波形好。