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《仪表技术与传感器》2016,(12)
根据城市公共安全管理的需求,设计并实现了一种基于物联网的燃气管网泄漏检测系统。采用高精度压电式动态压力传感器、无线传感器网络和GPS模块实现泄漏瞬变压力波信号的实时同步采集。为保证数据远程传输的实时性和可靠性,采用4G模块MC7710和STM32F405RG微处理器完成了4G网关的设计。远程数据中心采用基于互功率谱相位的广义互相关时延估计方法对现场信号分析和处理,实现了管网中燃气泄漏点的定位。实验结果表明,该系统数据传输稳定可靠,泄漏定位准确度高,能够满足燃气管网泄漏检测的需要。 相似文献
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《仪表技术与传感器》2016,(2)
文中研究了压力容器微小泄漏点的定位检测问题。基于FUS-40CR型超声传感器,研制了一套高灵敏度非接触超声测漏定位系统。该系统利用4个传感器实现了时差法的测漏定位,并利用Lab Windows/CVI软件编译了泄漏定位程序。利用该系统对设计的一个能够改变漏孔孔径和压力的小型压力罐进行了微小泄漏点的非接触定位检测实验。实验结果表明:在罐内气压为0.6 MPa、漏孔直径不小于0.2 mm的情况下,可以得到满意的定位测试结果。 相似文献
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在线极性相关器的研究 总被引:2,自引:0,他引:2
本文介绍了一种新型的微机化软硬结合的在线极性相关器,采用分级扫描,成功地解决了相关测量中实时相关分析的统计测量精度与响应速度的矛盾。该相关器已用于液固两相(纸浆)流量计中,获得了满意的结果。采用相关测量技术,是解决许多难测流体流速、流量测量的有效途径之一,在线相关器是相关测量的关键组成部分。我们研制的微机化软硬结合的在线极性相关器,成功地解决了在线极性相关分析统计测量精度与响应速度的矛盾,在液固两相(纸浆)流量计中得到了实际应用。为开拓相关分析的在线应用奠定了良好的基础。 相似文献
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蔡士祥 《现代制造技术与装备》2014,(1):1-4
为提高铸造桥壳中段测量精度和测量效率,文中提出采用专用测量设备实现在线测量,动态控制产品重要特性指标通过对产品结构和测量要求的深入分析,找出了测量装置设计中多点测头、测头防护、多品种快速切换装置等技术难点的解决方案,实现了铸造桥壳中段基于该装置实时在线测量,为桥壳中段的动态质量控制做出了创造性的探索 相似文献
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夹钳式超声相关流量计及其在液/固两相流测量中的应用 总被引:3,自引:0,他引:3
本文叙述了一种可应用于液/固两相流的夹钳式脉冲超声相关流量计。检测随机流动噪声用的两对超声波传感器,是用卡钳装置牢固地夹紧在被测管道的外壁面上,不和被测流体直接接触,不会对流体产生任何阻碍作用。在线实时相关器的设计,采用了极性相关和峰值溢出检测原理。为兼顾仪表的流速测量范围和测量精度的要求,采用了可自寻最佳采样频率的闭环反馈式方案。 相似文献
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供水管网泄漏定位研究与检测系统开发 总被引:3,自引:1,他引:3
在分析泄漏声波在管线中传播特性的基础上,根据自适应滤波时延估计与泄漏定位的原理,设计与实现了管网泄漏定位系统中的传感器及信号调理电路、数据采集与通信电路、数字滤波以及泄漏定位软件等,并进行了系统集成.在实现的系统中,传感器采集到的泄漏声信号被转换成12位数字量,通过通信端口读入计算机.为了得到准确的定位结果,对采集到的数据采用了选频段滤波、分时段时延估计、根据信号幅值的相对强弱进行抑制突发强干扰.现场试验与运行结果表明:系统硬件和软件流程运行正确,达到了设计的需求;泄漏定位结果误差小于0.5 m,能够满足实际测量的要求. 相似文献
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Clarence W.DE SILVA 《Instrumentation》2019,(4):72-84
An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t... 相似文献
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30 keV Ga+ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z2, and shows a non-monotonic relationship between contrast and Z2. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z2, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory. 相似文献
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This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an... 相似文献
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分布动态载荷识别的抗噪处理 总被引:2,自引:2,他引:0
针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性. 相似文献
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针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。 相似文献
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J. A. Williams 《Lubrication Science》1997,3(3):267-306
Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface. 相似文献
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M. Stedman 《Journal of microscopy》1988,152(3):611-618
Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space. 相似文献
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Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking
This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern... 相似文献
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以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可. 相似文献