一种嵌入式远程监测与诊断系统及其应用

介绍一种嵌入式远程监测与诊断系统的软、硬件结构与功能,该系统前端采用嵌入式采集模块,适用于十分恶劣的现场环境下的设备运行状态监测.系统针对性强、安装方便、开发成本低,客户端采用B/S模式,升级与访问方便.系统可将模拟信号转化成数字信号进行远程传输,有效地解决了信号在传输过程中的损耗问题.     

A new reference method for testing hydrometers

The two methods for determining the density or specific gravity of liquids used in testing hydrometers are: (1) comparison with standard reference hydrometers, and (2) hydrostatic weighing. In this paper, a new method for the determination of the density of liquids for the testing of hydrometers is described. The method involves determining the differential pressure between two points or planes separated vertically in a liquid and dividing the differential pressure by the product of the local acceleration due to gravity and the vertical separation. The system is based on sound scientific principle, is easy to use, is very precise, and is easily and accurately calibrated using water. The results for such a system are demonstrated for water and for nitric acid solutions. The precision is shown to be approximately 1 part in 10 000 or 0.01%, which is ideal for the testing of hydrometers the precision of which is about 1 part in 1 000 or 0.1%.     

A two-phase damping model on tube bundles subjected to two-phase cross-flow

An analytical model is developed to estimate the two-phase damping ratio for upward cross-flow through horizontal tube bundles. The present model is formulated based on Feenstra’s model (2000) for void fraction and various models (homogeneous, Levy, Martinelli-Nelson and Marchaterre) for two-phase friction multiplier. The analytical results of drag coefficient on a cylinder and two-phase Euler number are compared with the experimental results by Sim-Mureithi (2013). The correlation factor between frictional pressure drop and the hydraulic drag coefficient is evaluated by considering the experimental results. The two-phase damping ratios given by the analytical model are compared with existing experimental results. The model based on Marchaterre’s model is suitable for air-water mixture, whereas the Martinelli-Nelson’s model is suitable for steam-water and Freon mixtures. The two-phase damping ratio is independent of pitch mass flux for air-water mixture, but is more or less influenced by the mass flux for steam-water/Freon (134) mixtures. The two-phase damping ratios given by the present model agree well with experimental results for a wide range of pitch mass ratio, quality, and p/d ratios.     

RIPP化学计量学光谱分析软件3．0的开发

介绍了新版RIPP化学计量学光谱分析软件3．0的结构、主要功能及其特点。该软件具有模型传递、模型验证、参数自动筛选以及非线性校正等多项实用性强的新功能,模型界外样品识别等方法符合ASTM E-1655的要求。该软件具有界面友好、计算速度快、操作方便、结果稳健可靠等特点,非常适合应用于工矿企业,对科研部门也有重要的应用价值。     

产品知识模块本体的构建

对产品知识模块本体进行定义,并给出其内涵;提出了产品知识的模块划分思想,即从产品、部件、零件及零件特性等几个层次上采用结构模块方法对产品知识进行模块划分,并给出产品知识模块的正规化处理方法;对产品知识模块本体建模语言的选择及产品知识模块本体的维护等内容进行描述;给出了产品知识模块本体的构建过程,该过程包括产品知识的领域选择、模块划分、本体元素确定、本体语言选择、模块本体构建和动态本体进化等6个方面,并以实例说明该过程.     

最小包容区域法评定平面度误差的程序设计

介绍了最小包容区域法评定平面度误差的JAVA程序设计。采用三角形准则、交叉准则和直线准则分别求取最小包容区域,从三者中选取最小值作为平面度误差。得到的误差值具有唯一性。对数据采集的准备工作无特别要求,操作较简便。适用于三坐标测量机及其它仪器对平面度检测时数据的处理。     

激光焊接声、光信号监测仪的研究

介绍了激光焊接过程实时监测技术的理论根据，阐述了激光焊声、光信号监测仪的设计原理、方法及应用电路。试验表明：该仪器精度高、响应速度快、工作可靠，能满足实时监测的要求。     

离轴三反空间相机的焦距测量

离轴三反光学系统的焦距是空间相机的重要指标之一,离轴三反空间相机在完成光学系统装调及光学镜头装配后需要进行焦距测量。通过对两种经典的焦距测量方法即放大率法和测角法进行对比分析,选用测角法作为焦距的测量方法,同时对用于同轴光学系统的焦距测量公式增加离轴角修正量使其适用于离轴三反光学系统,并以某离轴三反空间相机为例论述焦距测量方法及步骤。由修正后的焦距计算公式计算出相机的焦距为8 010mm,证实了该测量方法的可行性。     

基于激光视觉的脉冲GTAW熔池振荡检测与分析

熔池振荡频率与焊缝全熔透状态有较为直接的物理对应关系,但熔池振荡频率的检测十分困难。针对该问题提出一种基于激光视觉的熔池振荡特征频率检测传感新方法。在介绍激光视觉法原理基础上,设计脉冲非熔化极气体保护焊(Gas tungsten arc welding, GTAW)熔池振荡激光视觉传感试验系统。采集反映熔池振荡变化的视频图像,提出激光特征条纹的图像处理算法,并利用Matlab软件编写相应的程序获得熔池振荡波形,利用快速傅里叶变换提取出熔池振荡特征频率。试验结果表明,激光视觉法不仅成功实现脉冲GTAW熔池振荡信号的检测传感,而且克服了已有的脉冲GTAW熔池振荡检测法不能被用于连续焊接的缺陷。软件系统能够较准确地提取出熔池振荡特征频率、处理时间为20 ms,满足熔池振荡信号的实时检测要求,为连续脉冲GTAW熔透控制奠定了基础。     

汽车波形套复合缩径-胀形变形分析与求解

提出汽车波形套成形的复合缩径-胀形工艺,设计了成形模具,给出了胀形用弹性介质的设计原则,建立了波形套复合缩径-胀形力学模型,推导出各变形区的静力平衡方程,在试验研究的基础上求解了各变形区的应变场及应力场.     

Characteristics of the inlet with the pressure perturbation in the ramjet engine

Flows in a ramjet inlet is simulated for the study of the rocket-ramjet transition. The flow is unsteady, two-dimensional axisymmetric, compressible and turbulent. Double time marching method is used for the unsteady calculation and HLLC method is used as a higher order MUSCL method. As for turbulent calculation, k — ω SST model is used for more accurate viscous calculations. Sinusoidal pressure perturbation is given at the exit and the flow fields at the inlet is studied. The cruise condition as well as the ground test condition are considered. The pressure level for the ground test condition is relatively low and the effect of the pressure perturbation at the combustion chamber is small. The normal shock at the cruise condition is very sensitive to the pressure perturbation and can be easily detached from the cowl when the exit pressure is relatively high. The sudden decrease in the mass flux is observed when the inlet flow becomes subcriticai, which can make the inlet incapable. The amplitude of travelling pressure waves becomes larger as the downstream pressure increases, and the wavelength becomes shorter as Mach number increases. The phase difference of the travelling perturbed pressure wave in space is 180 degree.     

扫描电镜背散射装置及数据处理系统

电子背散射衍射装置是获取材料的亚微米的范畴晶体学信息扫描电镜附件,此装置在观察材料的形貌及分析成分的同时研究材料的取向关系。本文介绍了背散射衍射接收系统,该系统的CCD以快速方式接收的灵 为5mlux,积累方式接收的灵敏度为10μlux,分辨率为512dpi,扫描卡最高的分辨率为4096X4096。并成功地安装在北京有色金属研究总院JSM－840扫描电镜上,此系统设计合理,结构简单,操作方便安全。同时根据Hough变换的原理,编写了识别电子背散射衍射花样的软件,实现了全自动实时识别此花样,给出相应的数据。     

基于PMAC的减摇水舱试验台控制系统设计

减摇水舱属于典型的船舶横摇减摇装置,装船前必须采用试验台验证水舱的减摇能力。水舱试验台能够模拟船舶横摇、横荡两个方向的运动,采用液压伺服系统驱动。为了能够满足水舱试验的要求,克服耦合干扰力,设计了数字控制系统,并采用PMAC运动控制器实现对试验台的控制,最后通过试验调节参数,使系统达到预期指标。     

加工方钻杆专用机床的铣头设计与分析

以加工方钻杆专用机床的铣头为研究对象,设计并分析其机械结构是否满足加工工件的需要。具体介绍铣头设计过程及结构布置形式,同时对其铣头结构进行有限元分析,建立铣头结构三维模型。对其模态分析后,得出了其铣头箱体的前六阶固有频率和振型,与铣头切削时的振动频率进行比较。分析结果为评定方钻杆机床的动态特性提供了依据,并且为具有与其相似结构的铣头提供了理论基础。     

变压器铁耗及铜耗在线测试方法研究

首先介绍了变压器损耗产生原理，通过与传统变压器损耗测试方法比较，提出了以电流、电压求和法测量变压器铁耗、铜耗的新方法，并详细阐述了用该方法在线测试变压器铁耗和铜耗的实现原理。选用三相自耦式变压器，纯电阻负载为对象进行模拟实验。以一相为例说明其模拟实验接线图，得到铁耗及铜耗在线测试数据，并对数据进行了误差分析。验证了在线测试变压器铁耗及铜耗原理的正确性。     

基于Compobus/D现场总线的装焊生产线监控系统

基于Compobus/D现场总线的装焊生产线监控管理系统 ,结构简单 ,运行可靠 ,抗干扰能力强并便于扩展 ,实现了对装焊生产线的实时监控及管理。该系统的使用对提高企业生产管理水平具有重要的应用价值     

Registering electrostatic discharges on board the Resurs-P spacecraft

The Shtil-М equipment is described, which is installed on board the Resurs-P spacecraft (SC) and is intended for measuring interferences via the power-supply bus, the voltage between the power-supply circuit and the SC housing, magnetic fields, and also for detecting electrostatic discharges. Maximum attention is drawn to the latter procedure. The module for registering electrostatic discharges is described in detail. A theoretical calculation of the voltage that is induced in the cable during land and full-scale experiments is presented. A technique for conducting land experiments is described and the obtained results are presented. The fact of the registration of an electrostatic discharge on board the Resurs-P spacecraft is confirmed.     

Sliding bearings used as seismic dampers with composite self-lubricating materials

The scientific basis for the design of self-lubricating self-aligning sliding bearings with reciprocal motion is presented for the first time. The bearings are used as seismic dampers for bridges, industrial and civil buildings, and oil and gas offshore structures; they are superior to known bearings in carrying and damping capacities. An original experimental-calculation method for determining the life of a frictional pendulum sliding bearing used as a seismic damper is elaborated. It implies the use of the dependences for the wear rate presented in generalized variables. A method for estimating the friction coefficient of frictional pendulum bearings is also developed. The outlook for domestic development of an antifriction self-lubricating coating with preset tribological characteristics is analyzed and the present state of the art is discussed. The studies are based on known developments in the field of tribological materials with account for modern advances in nanotribology. The most promising heat-resistant polymers and fillers, as well as combined mixed antifriction fabrics on their basis, are considered.     

太赫兹波纹喇叭制造工艺技术实验研究

传输太赫兹(Terahertz,THz)波的馈源结构的特征尺寸在亚毫米量级,且精度要求高.波纹喇叭馈源结构具有良好的电讯特性,但内腔结构复杂,制造难度大.针对太赫兹波纹喇叭的具体结构和技术要求,对微细加工和微电铸工艺技术进行了调研和分析,给出了一种利用这些技术的太赫兹波纹喇叭的精密成形工艺方案.开展了内腔筋宽为0.1 mm的波纹结构的工艺实验,为太赫兹波纹喇叭的精密成形提供了有益的工艺方法和工程经验.