基于STM32的无人机雪橇减震器检测与数据保存设备

为了能够对某型号无人机雪橇式减震器的最大静载荷试验进行实时检测和保存数据,设计了一种基于STM32F103ZET6单片机的雪橇式减震器检测设备。设备利用压力传感器和光栅尺分别完成减震器在压缩过程中,对静载荷与压缩距离的采集并转换为数字信号,信号在减震器压缩过程中的特定位置被采集,将采集到的信号通过无线模块上传至上位机;以C#平台开发的上位机作为收集、处理下位机传入的静载荷、压缩距离的信号,最后借助图形用户接口控件实现静载荷、压缩距离的曲线显示,将采集到的数据使用SQL数据库实现保存,以便于操作管理员读取和历史查询。测试结果表明：雪橇式减震器检测装置可以完成对减震器的自动化检测。     

基于STM32的嵌入式煤层压力监测系统设计

为了能够对煤层开采时的压力进行实时监测和数据保存,设计了一种基于STM32F103ZET6的嵌入式高精度多路压力采集系统;利用压力传感器和18位模数转换器FS511完成煤层压力的采集并转换为数字信号,通过数字开关CD4051实现通道转换,以实时操作系统μC/OS-II作为软件平台,处理压力数据,借助图形用户接口μC/GUI实现压力数据和曲线的显示,借助文件系统FATfs实现以文件的形式将数据保存在SD卡中,便于PC读取;利用CAN总线将数据传输至上位机,进行更为复杂的处理;测试结果表明:煤层压力监测系统精度达到0.01%;本系统精度高,实时性好,满足了矿山压力实验室的需求。     

基于PLC的加热炉温度曲线控制系统设计

为了补偿环境温湿度对望远镜系统的不利影响,提高大型光电望远镜的成像能力,设计了一种基于CAN总线的温湿度监测系统。系统采用总线式拓扑结构,主要由数字式传感器SHT15、C8051F500单片机、CAN总线以及上位机组成。单片机与传感器之间利用SMBus进行通信,单片机读取传感器数据后,经由CAN总线将数据传送到上位机,上位机实时处理显示温湿度信息。系统设计完成后在实验室中进行了验证实验,成功读取了两个节点的传感器采集到的数据,能够进一步应用于实际工作中。     

基于单片机和LabVIEW的无线火灾监测系统设计

设计了一款的RFTR1无线火灾监测报警系统,重点介绍系统的实现过程。系统以单片机STC12C5A60S2为核心控制器,利用LabVIEW开发环境设计上位机的监测界面,上位机通过串行口与单片机通信,从而实现对多路数据的采集与监测。设计并解释系统的硬件连接,对系统作软件设计,解释了LabVIEW监测平台的应用,经测试系统运行正常。系统具有无需布线、对功能变化的适应性强、系统数据及信息显示直观、人机交互界面好、抗干扰能力强、安装调试简便等特点。     

基于NRF24L01的降雨量实时采集无线监测系统

设计以AT89S52单片机为处理器,用集雨斗、盛水瓶、压力传感器组成数据采集模块,将采集到水的质量转换为降雨量;利用NRF24L01无线数据传输,通过串口将数据传到上位机,便于对历史降雨量的查询与研究;上位机软件采用VB进行设计,可以曲线的方式表示降雨量,自行设定降雨量的上限报警值;该系统成本低,安装方便,实现实时降雨量数据的无人采集,自动实时显示和存储,具有较大的推广价值。     

基于AVR的静压气体轴承性能检测装置控制系统设计

为了实现对静压气体轴承气膜厚度,压力分布和承载能力的自动检测,设计了一种基于单片机的检测装置和控制系统。该系统采用ATmega16L单片机作为平台运动控制和数据处理的核心,结合软件控制步进电机的转向和转速,实现了极坐标定位,并采集承载力,气膜压力和气膜厚度等数据,通过LCD显示和键盘输入,较好地实现了人机交互;同时,装置可以通过RS232与上位机通讯,实现上位机的直接控制。     

新一代DCS中智能温度监控系统设计与实现

传统的分布式温度监控方法存在费时费力、不便应用在特殊环境、不便用于多点融合监控等弊端,设计并实现了新一代DCS智能温度监控系统,通过核心为ARM7LPC2292芯片的下位机及时调整全部温控点的温度,自主设置温度、显示实际温度与报警;采用核心为89C51微处理器模块,将上、下位机的信息互相传递,确保上位机随时查询温度信息;通过CC2530终端节点实时采集测温终端的温度数据,将温度数据无线发送给CC2530协调器节点,不在采用传统的中转服务器方式,而是采用协调器节点通过串口与上位机进行通信,并在上位机中进行温度数据的处理和存储。软件设计过程中,对系统监控过程中上位机和下位机间的主从通信方式进行详细分析,并给出了系统温度监控数据通信传输的流程图,分析了系统实现温度监控的数据库访问代码以及温控曲线显示代码的设计。实验结果说明,所设计系统性能好、操作简单、控制准确率高。     

基于反馈式可定位云台控制系统设计与实现

摘要：针对原值监测对样品应具备准确定位监测及信息可控的要求,在云台中建立了偏转角度检测装置,采集云台偏转角度脉冲信息并反馈到解码器中,对脉冲信号通过建立偏转角度计算公式处理云台偏转角度信息,并反馈给上位机,从而在上位机操作台、解码器、云台三者间形成了反馈式可定位云台控制系统。实践表明,通过这种反馈式偏转角数据的引入,上位机随时根据下位机反馈的云台偏转角数据实时监控云台工作状态,实现操作台对云台的精确控制,从而提高云台的易操作性和智能化水平。     

基于相关性原理起重机负载电机监测系统设计

对起重机负载电机进行了研究,采用西门子公司的S7-200 SMART PLC采集负载电机的机械振动信号,通过工业Wi-Fi无线模块以无线数据包的形式将采集的数据汇总到上位机LabVIEW监测平台。上位机的LabVIEW监测平台对电动机振动信号进行相关性和频谱分析,将实时振动数据频谱信号和已知常见负载电机的轴承外圈故障、轴承内环故障和滚子故障三种典型的故障状态频谱信号进行相关性运算,得到实时信号与已知状态的相关系数;提出了以相关系数作为故障诊断判定阈值的方法进行故障诊断,实现了对起重机状态进行监测以及监控信息发布。     

某型瞄准线稳定测试系统RS232串行通信的研究

某型瞄准线稳定测试系统是用于测试和检验班组武器系统、轻型低空反导转管机枪等武器系统中的光电跟踪子系统瞄准线独立性能的专用设备;介绍利用LabWindows/CVI实现上位机与下位机之间的通信,设计了瞄准线稳定测试系统,分析了下位机需要实时检测的物理量信息;为了提高系统的可视性和实现对下位机的控制,通过RS232串行通信技术向上位机传输数据;对上位机利用LabWindows/CVI的控件实现数据采集,数据显示和存储进行了研究;实验结果表明,基于LabWindows/CVI的RS232串行通信的上位机数据采集与显示系统具有可视性强、操作简单等特性。     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.