蜂箱内多点温度检测系统

介绍了基于AT89C52单片机的蜂箱内多点温度检测系统软、硬件结构设计。详细介绍了PN结温度传感器的工作原理以及在温度采集系统中的应用;AD0809在A/D转换中的应用;最后给出了软件设计的主流程图。该系统对蜂箱内温度变化规律的研究具有重要的现实意义。     

Performance Analysis of Multiuser Diversity in MIMO Systems with Antenna Selection

In this paper, a framework is presented to analyze the performance of multiuser diversity (MUD) in multiuser point-to-multipoint (PMP) MIMO systems with antenna selection. Based on this framework, the tight closed-form expressions of outage capacity and average symbol error rate are derived for the multiuser transmit antenna selection with maximal-ratio combining (TAS/MRC) system, by which we show how and with what characteristics antenna selection gains, MIMO antenna configurations and fading gains impact on the system performance, with an emphasis on the study of multiuser diversity influence. From both theoretical and simulation results, our study shows that in multiuser PMP TAS/MRC systems an diversity order equals to the product of the number of transmit antennas, number of receive antennas and number of users can be achieved; what's more, users plays a key role in the system performance and can be viewed as equivalent 'virtual" transmit antennas, which is the source of the multiuser diversity inherent exists in the multiuser system. This kind of diversity can be efficiently extracted in the design of multiantenna systems.     

基于51单片机的酒精浓度监测系统设计

设计了一种借助MQ-3酒精传感器,以STC89C52单片机为核心控制处理器,LCD液晶显示并带有声光报警功能的酒精浓度检测系统。针对酒精浓度监测系统的整体设计以及硬件、软件的设计情况等进行研究和演示,最终实现酒精浓度的自动监测和报警功能,具有一定的使用和参考价值。     

Single‐Crystalline Dodecahedral and Octodecahedralα‐Fe2O3 Particles Synthesized by a Fluoride Anion–Assisted Hydrothermal Method

Despite significant advances in iron oxide nanoparticles, it is still a challenge to synthesize regular polyhedral single‐crystalline α‐Fe₂O₃ particles because the surface energies of several low‐index planes are fairly similar. In the work presented here, well‐dispersed and single‐crystalline dodecahedral and octodecahedral α‐Fe₂O₃ particles are synthesized by a facile hydrothermal method with the aid of F^? anions. The crystalline structure of the polyhedral particles is disclosed by various characterization techniques. The dodecahedral particles are of hexagonal bipyramidal shape and enclosed by twelve equivalent (101) planes. The octodecahedral particles are formed by adding six equivalent (111) planes on the two tips of a dodecahedral particle, that is, they are enclosed by twelve (101) planes and six (111) planes. The existence of F^? anions plays a crucial role in the control of polyhedral particle shape. The function of F^? anions in the shape formation of the polyhedral particles is proposed as follows: 1) A high concentration of exposed Fe³⁺ cations induces preferential adsorption of F^? anions on the (100) plane and leads to the slowest growth along the [100] direction. When the concentration of F^? anions is higher than 24 mM , a stable speed ratio of growth along the [001] and [100] directions results in the exposure of (101) planes. 2) With a lower concentration of F^? anions, six symmetrical (111) planes with low concentration of exposed Fe³⁺ cations are present at the tops of a dodecahedral particle to form an octodecahedron. Furthermore, the dodecahedral and octodecahedral α‐Fe₂O₃ particles show much stronger magnetism than the previously reported α‐Fe₂O₃ nanostructures, having coercivities of 4986 Oe and 6512 Oe, respectively. Such high coercivities are attributed to a large local magnetic anisotropy, which might be induced by the polyhedron with equivalent crystallographic planes and/or the presence of F^? anions.     

基于DSP和局域网的医疗护理监控系统的设计

随着社会的不断进步,人们对护理工作的要求也越来越高,护理工作好坏直接关系着医院的发展。因此,本文研究设计了一种基于DSP和局域网的医疗护理监控系统,并对此设计作了简要分析,促进了医院医疗护理工作的发展。     

Functional Materials for Memristor-Based Reservoir Computing: Dynamics and Applications

The booming development of artificial intelligence (AI) requires faster physical processing units as well as more efficient algorithms. Recently, reservoir computing (RC) has emerged as an alternative brain-inspired framework for fast learning with low training cost, since only the weights associated with the output layers should be trained. Physical RC becomes one of the leading paradigms for computation using high-dimensional, nonlinear, dynamic substrates. Among them, memristor appears to be a simple, adaptable, and efficient framework for constructing physical RC since they exhibit nonlinear features and memory behavior, while memristor-implemented artificial neural networks display increasing popularity towards neuromorphic computing. In this review, the memristor-implemented RC systems from the following aspects: architectures, materials, and applications are summarized. It starts with an introduction to the RC structures that can be simulated with memristor blocks. Specific interest then focuses on the dynamic memory behaviors of memristors based on various material systems, optimizing the understanding of the relationship between the relaxation behaviors and materials, which provides guidance and references for building RC systems coped with on-demand application scenarios. Furthermore, recent advances in the application of memristor-based physical RC systems are surveyed. In the end, the further prospects of memristor-implemented RC system in a material view are envisaged.     

某机载电子吊舱抗振动设计

介绍了某机载电子吊舱的抗振动、抗冲击设计方法。通过合理设计舱体骨架,并对分系统进行加固设计来提高某机载电子吊舱的机械环境适应能力。     

高压变频器助力华能邯峰电厂节能增效

本文主要介绍HARSVERT—A多电平型高压变频器助力华能邯峰电厂凝结水泵节能增效情况，结果表明，采用HARSVERT-A多电平型高压变频器对凝结水泵进行调速节能改造，具有投资省，见效快等特点。     

自启动、宽调谐的ps掺Yb双包层光纤激光器

对连续泵浦的自启动、宽调谐的ps脉冲掺Yb^3＋双包层光纤激光器进行了实验研究。采用20m单模掺Yb^3＋双包层光纤作为增益介质,利用77MHz射频信号的声光调制器（AOM）作为频移器以及体光栅构成外腔,得到了重复频率为1GHz、平均功率为56．3mW以及脉宽小于60ps的脉冲,激光器的调谐范围超过40nm。     

Biomimetic Hygroscopic Fibrous Membrane with Hierarchically Porous Structure for Rapid Atmospheric Water Harvesting

Sorption-based atmospheric water generation (SAWG) is a promising strategy to alleviate the drinkable water scarcity of arid regions. However, the high-water production efficiency remains challenging due to the sluggish sorption/desorption kinetics. Herein, a composite sorbent@biomimetic fibrous membrane (PPy-COF@Trilayer-LiCl) is reported by mimicking nature's Murray networks, which exhibits outstanding water uptake performance of 0.77–2.56 g g⁻¹ at a wide range of relative humidity of 30%–80% within 50 min and fast water release capacity of over 95% adsorbed water that can be released within 10 min under one sun irradiation. The superior sorption–desorption kinetics of PPy-COF@Trilayer-LiCl are enabled by the novel hierarchically porous structure, which is also the critical factor to lead a directional rapid water transport and vapor diffusion. Moreover, as a proof-of-concept demonstration, a wearable SAWG device is established, which can operate 10 sorption–desorption cycles per day in the outdoor condition and produce a high yield of clean water reaching up to 3.91 kg m⁻² day⁻¹. This study demonstrates a novel strategy for developing advanced solar-driven SAWG materials with efficient water sorption–desorption properties.