共查询到20条相似文献,搜索用时 15 毫秒
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V. L. Rychka 《Measurement Techniques》1961,4(8):654-658
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Weiliang Liu Shujie Duan Hang Du Hang Jiang Cuiting Sun Xiren Jin 《Journal of Modern Optics》2019,66(11):1215-1218
In this paper, we proposed a novel kind of periodic helical ultra-long period fiber grating (U-LPFG) for measuring the torsion rate and distinguishing the torsion direction. The sensor was fabricated by spirally deforming a common fiber by local heating for 4 periods. This method of fabrication was not only easy to implement, but also further increased the sensitivity of the grating to the torsion because of the spiral structure. This paper introduced the torsional characteristics of this sensor in detail and drew some relevant conclusions. Experimental results showed that the twist sensitivity of 0.085?nm/(rad/m). Meanwhile, the temperature sensing characteristic of the proposed U-LPFG was also tested as 68?pm/°C within the range of 30?°C ~210?°C. Therefore, this proposed sensor could achieve good results in simultaneously measuring the torsion rate and distinguishing the torsion direction, and it may have great potential in some practical applications. 相似文献
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提出了一种传感部分采用光纤Bragg光栅(Fiber Bragg grating,FBG)传感器的高频应变测试新方法.设计并构建了基于非平衡马赫-曾德(Mach-Zehnder)干涉仪的高频解调系统.完整的测试系统由FBG传感器、高频应变产生装置和解调系统三部分组成.所产生的应变信号的频率可以通过专门的实验装置来控制,这是一种广泛用于测试材料机械性能的变形分离式霍布金逊压杆(Split Hopkinson Pressure Bar,SHPB)实验装置,应变持续的时间根据与撞击弹性等径的冲锤长度计算.借助高频振动信号研究了测试系统可测信号的频率范围.给出了振动和冲击实验结果,并进行了讨论.所设计的系统可以实时测试动态应变的幅值,实验结果表明,该系统对频率为8kHz以下的信号具有好的响应. 相似文献
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Conclusions It is not recommended to evaluate on a dial balance the measuring efforts of instruments whose mechanisms include kinematic pairs with considerable friction. In order to obtain reliable results it is advisable to use in this case a stiff dynamometer. The criterion that an installation with a balance is unsuitable for such measurements consists of the presence of a pronounced nonuniformity in the pointer movement of the mechanism for a smooth displacement of its casing with respect to a balance pan. It is obviously assumed that the instrument's mechanism is in working order and the nonuniformity of its movement is not due to wear, fractures, or manufacturing defects.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 14–15, November, 1968. 相似文献
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简要分析啁啾光纤光栅的原理和色散特性,着重介绍了啁啾光纤光栅色散的几种测量方法,对它们采用的光源等设备、测量速度和精度方面作了比较. 相似文献
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简要分析啁啾光纤光栅的原理和色散特性,着重介绍了啁啾光纤光栅色散的几种测量方法,对它们采用的光源等设备、测量速度和精度方面作了比较. 相似文献
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The influence of frequency on the accuracy of electromagnetic field distribution measurements needed for image reconstruction is examined. Various factors having a bearing on the choice of the optimum frequency are considered for a frequency range of 0.1-20 MHz, which is practical for geotomography. Most of the evidence indicates that the highest possible frequencies should be used, but this entails an increase in the attenuation coefficient. The increase is not synonymous with a commensurate reduction in the maximum distance from the electromagnetic field source, over which measurements can be made. The images reconstructed from the data measured in the area of intensive mining exploration were also presented in this paper. The reconstruction was performed using the one-step-late algorithm. 相似文献
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Yu. A. Polyakov 《Measurement Techniques》1969,12(10):1485-1487
Conclusions The above analysis is of a sufficiently general nature and its results can be extended beyond the range of microand millisecond measurement techniques.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 101–102, October, 1969. 相似文献
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针对目前国内还没有在环境监测中广泛使用的对工频电场探头进行计量的检定规程或者校准规范,设计了一套工频电场探头校准装置,根据理论推导,确定所产生标准电场强度。通过高压源控制器来控制升压实现高压输出。校准所采用的电板满足所有工频电场测量仪校准需求,产生的电场强度范围从10 V/m到100 kV/m。最后,对溯源后的HI-3604分别进行电场强度测试与分析,实验数据表明:该校准装置可以用于工频电场探头校准,并给出了校准不确定度。 相似文献