Windows下实时测控系统的实现

结合某型号导引头仿真测控系统的开发过程，说明了Windows环境下多媒体定时器的运行机制。并利用Visual C 语言编程实现精确定时，该系统可实现1ms的定时精度。     

全波段光窗玻璃及微晶化

研究了GeSe2-Ga2Se3-MX(M=Cs,K,X=I,Br,Cl)系玻璃的形成和性能。研究表明,这些系统均具有较大的玻璃形成区,其中,GeSe2-Ga2Se3-CsI系统的成玻能力和热稳定性最佳。随碱金属卤化物含量的增加,GeSe2-Ga2Se3-MX玻璃的短波吸收限逐渐蓝移至可见光区(可至550 nm以下),长波截止边无明显变化,部分玻璃在0.6~16μm范围内具有良好的透过率。玻璃的转变温度Tg、显微硬度Hv、断裂韧性K1c和弹性模量E随卤化物的含量增加而减小,而膨胀系数α增大。研究发现,该系统玻璃随热处理温度的提高,首先发生滴状分相,随后在滴状分相区内产生析晶。通过采取合适的热处理制度,研制获得了具有较好的K1c和红外透光性的微晶玻璃。研究结果表明,GeSe2-Ga2Se3-MX硫卤玻璃和玻璃陶瓷是一种具有应用前途的全波段透射和红外透射材料。     

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。     

电信网网管系统软件测试的必要性研究

从现有的电信网网管系统入手,分析其结构和未来发展趋势,强调了软件是其未来发展核心这一概念;接着阐述了为实现发展目标而引入的新技术给网管系统带来的影响以及消除影响的方法,尤其是软件测试所起到的作用;最后简述了针对网管软件特点的测试方法和测试项目。     

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.     

UC3875在超声电源功率控制系统中的应用

根据超声波发生器的功率控制系统原理 ,阐述了移相控制策略对超声波发生器输出电压波形的影响 ,介绍了移相控制专用芯片UC3875的电路结构和使用设计方法。     

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。     

低秩及几何约束的嵌入式阵列膛口波测向方法

针对部分阵元受壳体遮挡导致的小型嵌入式麦克风阵列枪声探测系统目标定位偏差问题,提出了一种枪声膛口波测向新方法。该方法通过分析非通视传播对阵元间波达时间差（TDOA）的不利影响,采用低秩及几何约束下的凸优化校正算法抑制实测TDOA矩阵中的随机噪声和衍射传播偏差;同时选取距离目标最近的通视麦克风作为参考阵元,进一步减小最小二乘测向偏差的统计均值与方差。外场试验结果表明,膛口波测向误差不大于实际产品指标要求的累积概率,由常规方法的0.86提升至新方法的0.94.