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无损检测和结构健康监测是保障工业生产安全、降低维护成本的重要技术。在结构健康监测领域,原位测量仪器的长期稳定性尤为重要。首先介绍电磁、超声无损检测在厚度检测的应用现状,针对随后讨论厚度无损检测检测仪器精度长期稳定性问题。对厚度无损检测仪器现在长期使用过程中的精度变化规律进行研究,探讨三种测厚仪器的工作原理、精密度和准确度与仪器的稳定性的关系。采用三种厚度测量仪器(超声测厚仪、涂覆层测厚仪与楼板测厚仪)测量预标定样本的仪器试验测量方法,得到五年测量数据。再通过分析数据的年平均误差、相对误差和变化速率来讨论电涡流测厚仪、超声测厚仪的长期稳定性,并进行三类仪器间的比较,分析各类型仪器的特点。结果显示电涡流厚度测量仪器具有相对较好的长期稳定性;超声测厚仪和楼板测厚仪精密度维持能力受时间影响,仪器精密度逐年下降,准确度也趋于不稳定。为电磁无损检测技术应用到结构健康监测领域,自校准和补偿奠定了基础。 相似文献
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The vibration/noise of gears is influenced by micrometer-order tooth pitch deviation, and therefore advanced quality control is needed in the gear manufacturing process using measuring instruments. The accuracy of the pitch measuring instrument is verified using a master gear or artifact, but its accuracy is not sufficiently high, and its manufacture is difficult. In our previous report, a novel pitch artifact named the magnetically self-aligned multiball pitch artifact, in which elements with simple geometries are aligned spontaneously by a magnetic force, was proposed for the calibration of pitch measuring instruments. The parts comprising the artifact, which consist of balls, a cylinder, and a plane, have simple geometries and can be manufactured with accuracies on the order of several tens of nanometers. Therefore, this artifact can also have high accuracy. In addition, because it undergoes self-alignment by a magnetic force, it has the advantage of easy assembly. An appropriate calibration method for this artifact using a coordinate measuring machine is proposed, and the accuracy of the artifact is evaluated in this report. The repeatability of pitch measurements when the artifact is disassembled and reassembled is investigated, and the results show high repeatability. A measurement experiment using a pitch measuring instrument is performed. These experiments verified that the calibration and measurement of the proposed pitch artifact are possible with high repeatability. 相似文献
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介绍一种用于校验数字表及模拟式指针表,特别是电动式表的大功率可程控多功能标准泊。其价格只有进口机的四分之一到十分之一,准确度为0.05%,可按电表校验规程对0.2级以下的交直流电压,电流指针表及数字表进行基本误差,升降变差、线性度等校验,误差及输出电量直读并可在其分辨率范围内任意设定。此外,还能对指针表进行点格,扫掠检验扎针情况。仪器具有自校准功能并带有GPIB接口和先进可靠的自保护电路。 相似文献
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Gear noise is influenced by pitch deviation of micrometer order, and, therefore, the pitch of gears is inspected in manufacturing processes using measurement instruments. Master gears or artifacts are used to evaluate the accuracy of the pitch measurement instrument, but their accuracy is not sufficiently high and they are not easy to manufacture. In a previous study, the concept of a novel high-precision pitch artifact composed of simple components was proposed for the evaluation of the accuracy of pitch measurement instruments. Simple components, such as balls, cylinders, and planes, can accomplish an accuracy on the order of several tens of nanometers. Therefore, this artifact can be realized with high accuracy. In the present study, we propose a spring-force self-aligned multiball pitch artifact, in which simple components are assembled using spring force. The design of the artifact is discussed, and the artifact is manufactured. Measurement experiments using a coordinate measurement machine and a pitch measurement instrument are carried out, and the proposed pitch artifact is demonstrated to be fundamentally valid for accuracy evaluation. 相似文献
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近年来,我国量具量仪行业根据市场需求,加强了开发设计能力,并通过引进国外技术,开发生产了多种新型量具量仪。本文介绍了我国工具工业在电子数显量具、三坐标测量机、车间现场用量仪、齿轮量仪和高技术高精度量仪产品等开发方面取得的成就。指出,CNC技术、微机控制、计算机数据处理和计算机辅助提高精度(CAA)等的应用,是近年来我国量具量仪的技术发展动向。 相似文献
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N.M. Kita 《Flow Measurement and Instrumentation》1994,5(4):289-294
CMFs are gaining a good reputation in the metering of liquid. However, because of some undesirable influences of the process parameters and fluid properties of the meter characteristics, it is recommended that the instrument be calibrated in situ when high accuracy must be achieved and/or the metering conditions (process parameters and fluid properties) differ noticeably from the calibration conditions. Field calibration is not always technically feasible and/or economically desirable. Therefore it is important to be able to predict the behaviour of the instrument. Taking the example of gas measurement, it is shown that straight pipe CMFs fulfil this requirement. 相似文献
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在确定工艺运行正常的前提条件下,如果仪表在线监测指标与工艺(或化验室抽检指标)不符合时,污水处理企业需对在线监测仪表进行校准。需介绍了污水处理企业在线监测仪表在线校准的方法。 相似文献
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汽车尾气中的挥发性有机物(VOCs)是主要的人为排放污染源之一,排放到大气环境中的VOCs具有很高的反应活性,能够参与臭氧的生成,是形成二次有机气溶胶等污染物的重要前体物质。因此,研制开发适用于现场实时、在线检测VOCs的便携式分析仪器,是现代科学仪器发展的重要方向之一。本工作利用苯系物标准气体对自行研制的便携式膜进样真空紫外灯单光子电离飞行时间质谱仪整机进行性能测试,仪器的质量分辨率优于350,质量精度优于1×10-4,对苯系物的检测限可达μg/m3级,动态范围优于3个数量级,仪器的总质量小于25 kg。将仪器放置户外对汽车尾气进行现场测试,基于该仪器高时间分辨率的特点,初步研究了汽车尾气排放VOCs的变化趋势与发动机工作状态的相关性。该仪器有望应用于环境应急事故、现场长期监测、化工园区生产工艺过程监控以及无组织排放等领域。 相似文献
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在嵌入式WinCE.NET环境中,提出了一种基于Modubus协议的流量标准装置控制系统的设计方案,通过RS-485总线实现Wincon-8031与下位机(PLC和二次仪表)信息交换,获取流量计校验过程中的系统参数(温度、压力、电压、电流等)、控制标志信号和被校验流量计的脉冲数、校验时间,以及向PLC下传设定参数和命令信号;给出了采用VB.NET2003实现Wincon8000与智能仪表通信的方法。在实际项目中得到了成功应用,验证了它的可靠性和稳定性。 相似文献
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分析用光学仪器的迅速发展是近年来令人注目的。原理新颖、性能优异、计算机化和自动化程度高的新仪器不断涌现,仪器制造工艺水平明显提高,不同门类仪器联用化成为潮流,适应市场需求的中小型仪器大量上市,都是明显的发展趋势。本文就分析用光学仪器的发展、趋势及我国光学仪器界应做的工作,作了简略的分析和探讨,提出了若干建议。 相似文献
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随着电力系统自动化水平的不断提高,电气仪表测量工作已越来越多的和新设备、新装置、新技术的应用结合在一起,电气仪表在很大程度上决定了日后的生产过程能否正常运行。本文就电气仪表的选型、安装与调试过程中需要注意的一些问题进行了简要的论述。 相似文献
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The vibration/noise of gears is influenced by micrometer-order tooth pitch deviation, and therefore, advanced quality control is needed in the gear manufacturing process using measuring instrument. The accuracy of the pitch measuring instrument is verified using a master gear or artifact, but its accuracy is not sufficiently high, and its manufacturing is not easy. In our previous report, a novel high-precision pitch artifact composed of simple-shape parts (“multiball pitch artifact”) was proposed for the calibration of pitch measuring instruments. Simple-shape parts such as balls, cylinders, and planes can be manufactured with several-ten-nanometer-order accuracy. Therefore, this artifact can also have high accuracy. In this study, a magnetically self-aligned multiball pitch artifact is proposed in which the simple-shape parts are assembled with high precision using magnetic force without any special assembly technique. The artifact is designed and manufactured. A measurement experiment using a pitch measuring instrument is performed, and it is verified that the proposed pitch artifact is fundamentally valid for calibration. 相似文献
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《Flow Measurement and Instrumentation》2001,12(2):113-121
This paper offers an initial explanation of the impact of component precision on the performance of complex instruments. It is argued that the traditional approaches to tolerance and quality control pay insufficient attention to the performance of complex products. It is believed that more sophisticated approaches to a consideration of precision, both in component production and assembly, could lead to substantial improvements in the accuracy of products.In this paper the case of the production process for thermal mass flowmeters is used to illustrate the issues. The parts of the process likely to affect the precision of the finished product, and currently requiring special calibration during production, are identified. Three aspects of these flowmeters are analysed: the concentricity of the sensor (transducer) insert, the insertion length of the sensor, and the effect of the clearance hole through which the sensor is fed into the flow tube. It is concluded that the total effect could be as much as 7%, with the sensor the most likely element to cause variation in the performance of the flowmeter. Some conclusions are drawn about the significance of these results for the general issue of production precision. 相似文献
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随着科技现代化发展,尤其在环境、生态、生物医学、航空航天、民用和家用电器等等领域,人们对小型(微型)分析化验、检测计量仪器的需求快速上升;同时,这些年来在科学仪器设计、制造领域的理论和工艺快速进展、激光、微电子器件和计算机控制处理软件日益优化,为科学仪器小型化发展提供了必要又充分的条件。因此,不但在科技发达国家而且也在我国掀起了研究、制造、应用小型(微型)分析检测仪器的发展潮流。本文拟对我国科学仪器小型化发展涉及的原则、方向和具体做法提出一些看法,供大家参考。 相似文献
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卫星遥感器的在轨交互定标是保证仪器数据记录的可靠性、连续性和一致性的核心方案,配合高精度的在轨参考基准仪器可使定标精度达到2%左右。本文介绍了交互定标技术的相关概念和意义,强调该技术是修正仪器间辐射定标相对偏差的重要手段。指出了交互定标的前提条件及现存难点。总结了交互定标实现流程,包括数据收集、匹配、筛选、处理,基准确定,精度分析等,分析了影响交互定标精度的各种因素。叙述了当前卫星光学遥感器交互定标的各类方法及其使用条件,总结了不同应用条件下所适用的各交互定标方法的定标精度。最后结合当前交互定标的国际合作活动,分析展望了未来光学遥感器在轨可溯源SI定标方法的前景趋势和难点问题。 相似文献