MIMO—OFDM低延迟信道估计改进算法

为了克服多输入多输出正交频分复用（MIMO—OFDM）移动系统中采用空间复用技术的下行链路性能出现衰退现象,提出一种信道估计改进算法。它根据信道状态并通过一个决策指导方案为4×4 MIMO系统提供大约4bit／s／Hz的数据。通过使用LDPC短码,在LDPC译码器输出端采用MIMO—OFDM符号重建方法,达到提高估计精度的目的。在3GPP MIMO空间信道模型下进行了仿真验证,结果表明指定速率下的估计精度得到改善。     

基于模糊控制的自动供水教学系统的设计

恒压供水系统是机电类专业教学中常用的典型系统。在分析和比较国内外自动控制恒压供水教学系统的前提下,以PLC为控制器,采用模糊控制技术、变频技术,设计出供水控制教学系统,该系统注重节能,符合人体工学,对于培养学生的独立思考能力,学习能力和动手能力有极大的促进作用。操作方便,功能完善,设计思路可为同类教学用控制系统提供借鉴。     

基于FPGA的图像匹配算法实现的研究

图像匹配的主要特点是数据运算量极大,并且图像匹配运算消耗的时间相对较长。由于FPGA本身并行的工作机制,使得FPGA能在进行图像匹配的时候可以快速处理这些大量的数字图像数据。本文首先介绍了图像匹配的基本原理,包括图像匹配的概念,图像匹配的方法,其匹配流程,然后重点介绍了两种图像匹配算法在FPGA中的实现过程,编写出了verilogHDL的核心代码,最后通过Quartus II软件进行综合编译,仿真出了其RTL级视图。     

物联网感知层标准体系架构研究

从感知层在物联网体系架构中的重要性出发,结合感知层的共性需求和特定需求,提出一种物联网感知层的标准体系架构,并对其中各模块进行详细介绍,最后总结下一步的研究方向。     

基于DAC的电阻层析成像系统激励信号源设计

为了解决传统电阻层析成像系统中激励信号源的问题,如电路的频率、幅值调节困难,电路设计模块复杂等问题,本文设计了一种新的电阻层析成像激励信号源产生系统。该系统利用微控器控制DAC芯片产生幅度频率可调的激励信号,该信号驱动精密电压/电流转换电路后产生双极性脉冲电流激励信号。研究表明,此系统可以满足使用要求,同时,在一定程度...     

基于光照重映射的低照度图像增强算法

目前,大量低照度图像中存在不同程度的饱和区域,这些图像主要是由前后背景亮度差异较大而形成的.对于该类低照度图像,如何在增强低照度区域的同时,尽量保留饱和区域细节纹理成为研究的难点.提出了一种基于光照重映射的低照度图像增强算法,该算法从相机成像原理出发,利用相机响应模型,通过区域化处理和非线性变换对亮度信息进行重新调整....     

Inorganic Electron Transport Materials in Perovskite Solar Cells

In the past decade, the perovskite solar cell (PSC) has attracted tremendous attention thanks to the substantial efforts in improving the power conversion efficiency from 3.8% to 25.5% for single-junction devices and even perovskite-silicon tandems have reached 29.15%. This is a result of improvement in composition, solvent, interface, and dimensionality engineering. Furthermore, the long-term stability of PSCs has also been significantly improved. Such rapid developments have made PSCs a competitive candidate for next-generation photovoltaics. The electron transport layer (ETL) is one of the most important functional layers in PSCs, due to its crucial role in contributing to the overall performance of devices. This review provides an up-to-date summary of the developments in inorganic electron transport materials (ETMs) for PSCs. The three most prevalent inorganic ETMs (TiO₂, SnO_2, and ZnO) are examined with a focus on the effects of synthesis and preparation methods, as well as an introduction to their application in tandem devices. The emerging trends in inorganic ETMs used for PSC research are also reviewed. Finally, strategies to optimize the performance of ETL in PSCs, effects the ETL has on J–V hysteresis phenomenon and long-term stability with an outlook on current challenges and further development are discussed.     

Rational Designs for Lithium-Sulfur Batteries with Low Electrolyte/Sulfur Ratio

Lithium-sulfur batteries (LSBs) are considered a promising next-generation energy storage device owing to their high theoretical energy density. However, their overall performance is limited by several critical issues such as lithium polysulfide (PS) shuttles, low sulfur utilization, and unstable Li metal anodes. Despite recent huge progress, the electrolyte/sulfur ratio (E/S) used is usually very high (≥20 µL mg⁻¹), which greatly reduces the practical energy density of devices. To push forward LSBs from the lab to the industry, considerable attention is devoted to reducing E/S while ensuring the electrochemical performance. To date, however, few reviews have comprehensively elucidated the possible strategies to achieve that purpose. In this review, recent advances in low E/S cathodes and anodes based on the issues resulting from low E/S and the corresponding solutions are summarized. These will be beneficial for a systematic understanding of the rational design ideas and research trends of low E/S LSBs. In particular, three strategies are proposed for cathodes: preventing PS formation/aggregation to avoid inadequate dissolution, designing multifunctional macroporous networks to address incomplete infiltration, and utilizing an imprison strategy to relieve the adsorption dependence on specific surface area. Finally, the challenges and future prospects for low E/S LSBs are discussed.     

Organic Synaptic Transistors: The Evolutionary Path from Memory Cells to the Application of Artificial Neural Networks

The progress of neural synaptic devices is experiencing an era of explosive growth. Given that the traditional storage system has yet to overcome the von Neumann bottleneck, it is critical to develop hardware with bioinspired information processing functions and lower power consumption. Transistors based on 2D materials, metal oxides, and organic materials have been adopted to mimic the synapse of a human brain, due to their high plasticity, parallel computing, integrated storage, and system information processing. Among these materials used to build transistors, organic semiconductors are considered to be the most promising candidate for neural synaptic devices and bio-electronics, owing to their easy processing, mechanical flexibility, low cost, good bio-compatibility, and ductility. This review focuses on the recent advances in organic synaptic devices with various structures, materials, and working mechanisms. The applications of artificial neural networks that integrate multiple organic synaptic transistors are also concretely discussed. Finally, the challenges that organic synaptic devices currently face are discussed and future developments are forecast.     

Nacre-Inspired,Liquid Metal-Based Ultrasensitive Electronic Skin by Spatially Regulated Cracking Strategy

The realization of liquid metal-based wearable systems will be a milestone toward high-performance, integrated electronic skin. However, despite the revolutionary progress achieved in many other components of electronic skin, liquid metal-based flexible sensors still suffer from poor sensitivity due to the insufficient resistance change of liquid metal to deformation. Herein, a nacre-inspired architecture composed of a biphasic pattern (liquid metal with Cr/Cu underlayer) as “bricks” and strain-sensitive Ag film as “mortar” is developed, which breaks the long-standing sensitivity bottleneck of liquid metal-based electronic skin. With 2 orders of magnitude of sensitivity amplification while maintaining wide (>85%) working range, for the first time, liquid metal-based strain sensors rival the state-of-art counterparts. This liquid metal composite features spatially regulated cracking behavior. On the one hand, hard Cr cells locally modulate the strain distribution, which avoids premature cut-through cracks and prolongs the defect propagation in the adjacent Ag film. On the other hand, the separated liquid metal cells prevent unfavorable continuous liquid-metal paths and create crack-free regions during strain. Demonstrated in diverse scenarios, the proposed design concept may spark more applications of ultrasensitive liquid metal-based electronic skins, and reveals a pathway for sensor development via crack engineering.