共查询到18条相似文献,搜索用时 46 毫秒
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为了延长固定点黑体容器使用寿命和简化使用流程,依据热管黑体和传统石墨坩埚黑体的设计使用经验,研制了改进型封装固定点黑体。针对所研制的锡固定点黑体分别用二等标准铂电阻和传递辐射温度计开展复现测试。改进型封装固定点黑体在经历20余次熔凝循环后,没有出现破裂和金属泄露现象。用标准铂电阻复现多次的平均值为231.909℃,扩展不确定度为0.015℃(k=2);而用固定点黑体校准传递辐射温度计的多次平均值为231.85℃,扩展不确定度为0.096℃(k=2)。 相似文献
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本文提出了传统辐射测温的优点和缺点,并讨论了一种特定波长的辐射测温模型,通过对谱色测温法模型的数学分析得出了辐射测温的条件式,同时揭示了在一定波长下,这种测温方法理论上可以为辐射测温计量提供新的思路. 相似文献
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玻璃工业生产过程是辐射测温技术应用最重要的领域之一.给出了实际测温过程等温与非等温两种情况下建立的数学模型.提出了有效深度的概念,将有效温度与表面温度联系起来,通过表面温度的测量确定有效温度,提高玻璃生产过程中温度测量的准确性.文中并指出波长选择在玻璃表面温度测量中的重要性. 相似文献
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基于主动式双波长红外激光的测温方法,可实现对未知发射率表面真实温度的测量。高精度的标定源是保证双波长红外测温系统测温精确性的重要基础,但目前双波长测温领域的研究工作缺乏关于标定实验结果的公开报道。因此,设计搭建了主动式红外激光测温标定源,研究该标定源的稳定性和均匀性,并对双波长激光测温系统进行标定。结果表明:所搭建主动式双波长红外激光测温标定源稳定性良好,1 173 K时20 min内温度最大偏差为0.22 K;表面温度均匀性良好,1 173 K时表面温度标准偏差为0.34 K;标定源表面真温在923 K以上时,采集信号相对标准偏差小于0.7%。标定实验结果证明所搭建标定源可靠性良好,能够对主动式双波长红外激光测温系统进行精确标定。 相似文献
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文章讨论了谱色测温系统研究中,基于测温坐标系的辐射测温区域的界定问题。以线性发射率模型以及改进的单调发射率模型为基础,通过测温坐标系标尺的考察,分析了不同光谱发射率模型下的辐射测温坐标系所限定的辐射测温有效区域的规律特征;以实际应用中特定的谱色测温仪器为例,给出该仪器适用的辐射测温的理论区域,并用黑体实验进行了验证。 相似文献
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目前,变频系统故障诊断还一直依赖于对电压和电流信号的监测与分析,现提出用改进小波包提取变频器故障信号的特征量,并将该特征向量作为改进型网络的学习样本进行训练的方法.仿真结果表明,改进型小波神经网络与常规神经网络诊断方法相比,具有准确度高、诊断速度快和泛化能力强等优点. 相似文献
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从辐射测法中辐射率变化对温度的影响,讨论了多色辐射测量法的发展与应用实践,比较了不同处理方法的优缺点。 相似文献
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LIUQi-peng FENGQuan-ke XIONGWei 《国际设备工程与管理》2004,9(2):72-78
Fault diagnosis is confronted with two problems; how to “measure“ the growth of a fault and how to predict the remaining useful lifetime of such a failing component or machine. This paper attempts to solve these two problems by proposing a model of fault prognosis using wavelet basis neural network. Gaussian radial basis functions and Mexican hat wavelet frames are used as scaling functions and wavelets, respectively. The centers of the basis functions are calculated using a dyadic expansion scheme and a k-means clustering algorithm. 相似文献
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C. Monte B. Gutschwager S. P. Morozova J. Hollandt 《International Journal of Thermophysics》2009,30(1):203-219
A new experimental facility was realized at the PTB for reduced-background radiation thermometry under vacuum. This facility
serves three purposes: (i) providing traceable calibration of space-based infrared remote-sensing experiments in terms of
radiation temperature from −173 °C to 430 °C and spectral radiance; (ii) meeting the demand of industry to perform radiation
thermometric measurements under vacuum conditions; and (iii) performing spectral emissivity measurements in the range from
0 °C to 430 °C without atmospheric interferences. The general concept of the reduced background calibration facility is to
connect a source chamber with a detector chamber via a liquid nitrogen-cooled beamline. Translation and alignment units in
the source and detector chambers enable the facility to compare and calibrate different sources and detectors under vacuum.
In addition to the source chamber, a liquid nitrogen-cooled reference blackbody and an indium fixed-point blackbody radiator
are connected to the cooled beamline on the radiation side. The radiation from the various sources is measured with a vacuum
infrared standard radiation thermometer (VIRST) and is also imaged on a vacuum Fourier-transform infrared spectrometer (FTIR)
to allow for spectrally resolved measurements of blackbodies and emissivity samples. Determination of the directional spectral
emissivity will be performed in the temperature range from 0 °C to 430 °C for angles from 0° to ±70° with respect to normal
incidence in the wavelength range from 1 μm to 1,000 μm.
References to commercial products are provided for identification purposes only and constitute neither endorsement nor representation
that the item identified is the best available for the stated purpose. 相似文献
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This article presents a graphical method to calculate reflection corrections for radiation thermometry. The method is based
on the observation that the measured radiance of a target is a linear combination of radiances dependent on the emissivity
of the target. The method is most easily implemented as a nomogram, enabling thermometer users to estimate reflection corrections
immediately when measurements are taken. The nomogram also provides a visual means of explaining the impact of reflection
errors on measurements and for explaining the impact of measurement uncertainties on temperature measurements corrected for
reflections. 相似文献
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集成小波神经网络在故障诊断中的应用研究 总被引:3,自引:0,他引:3
以非线性Morlet小波基作为激励函数,形成神经元,结合小波变换与神经网络各自的优点,建立集小波分析与神经网络于一体的紧致型小波神经网络,并给出了具体的算法。基于信息融合技术的思想,从设备故障诊断的实际出发,建立了基于信息融合技术的集成小波神经网络故障诊断系统,即通过故障特征信息的有效组合,用各种子小波神经网络从不同侧面对设备故障进行初步诊断,然后对诊断结果进行决策融合。给出了系统的实现策略和子网络的组建原则。从诊断实例中可以看出,此诊断系统充分利用各种特征信息,可以有效的提高确诊率。 相似文献