液体闪烁核活度计量仪

本文描述用液体闪烁计数法直接测定α、β发射体溶液放射性活度的计量仪器。该仪器包括三个光电倍增管的符合探测器和三个输出计数道;以三重对两重符合计数率之比(TDCR)为猝灭参数,通过外推效率曲线至TDCR=1直接得到核素的活度。该仪器用于放射性活度绝对测量至少有两个突出的优点:1.精确度较高,对~3H、~(63)Ni和~(14)C等多种β、α核素其总测量不确定度(3σ)在0.5—1.5％;2.操作简便,测量迅速。     

CNC式高准确度滚刀测量机

本文阐明了滚刀测量机的工作原理、系统组成、技术关键及采取的措施。本测量机是针对滚刀的几何特点、采用CNC技术而研制的电子创成式仪器,其突出特点是能对高精度滚刀(AAA级)和修形滚刀实现快速测量     

Geometry of the minimum zone flatness functional: planar and spatial case

The zone straightness and flatness functional is constructed from the definition of the measure. The geometry of the straightness functional is illustrated in the plane, and in three dimensions, a novel means to visually represent flatness is described using the zone separation body. The zone separation body is a new construction that is uniquely associated with every measurement dataset and can be used to represent the flatness functional visually.     

Uncertainty estimation of a liquid flow standard system with small flow rates

A liquid flow standard system is used to calibrate liquid volume of fuel–oil flow meters at small flow rates between 50 L/h and 700 L/h. However, the system has not been used to calibrate volume flow rate because the system is only operated with the standing-start-and-finish mode. In this study, the liquid flow standard system was rebuilt to provide a calibration service of volume flow rate by attaching two flow diverters, which can operate the system with the flying-start-and-finish mode. To evaluate its performance for volume flow metering, several techniques were introduced. First, diverter timing errors were estimated by linear regression. Second, covariance between buoyancy correction factor and water density was obtained to consider interdependency between the two measurands. Third, calibration and measurement capability (CMC) was evaluated by setting a fixed value of collected weight or elapsed time for flow diversion. Finally, several CMCs were compared to find the best measurement condition. As a result of the above approach, the CMC of the liquid flow standard system was found to be (0.10–0.52)% (k = 2) for (50–700) L/h with a minimum collected weight at 10 kg.     

光反馈自混合干涉对称折叠算法的精度分析

为了提高对称折叠算法的精度,通过对仿真信号的测量,分析了影响算法精度的几种因素(光反馈水平因子,外腔的非线性运动,抽样速率和转折点的定位),并且给出了改进方法.仿真结果表明,在测量线宽展宽因子之前,需保证光反馈水平因子的准确测量,利用中间干涉条纹进行测量可以减少外腔非线性运动所带来的误差.这一结论对利用对称折叠算法处理实验信号有一定的帮助.     

台阶法标定干涉仪频率响应函数

大口径移相干涉仪在检测空间频率为毫米甚至亚毫米量级的相位误差时, 存在部分空间频率的相位误差失真效应。因此, 必须对大口径移相干涉仪的频率响应函数进行标定,以保证检测数据的真实性。引用评价参数-功率谱密度, 重点研究了干涉仪频率响应函数的实验标定。在理论上建立标定干涉仪频率响应函数的数学模型, 讨论了两种标定方法—正弦相位光栅法和台阶法, 分析其各自的优缺点, 综合比较后确定台阶法作为实验方案。深入研究台阶样品可以作为标定用标准台阶的条件, 即台阶阶跃的陡峭程度与台阶信噪比的选择, 探讨了台阶法标定干涉仪频率响应函数的可行性; 设计、制作了高精度的台阶相位板, 结合实验对干涉仪的频率响应函数进行标定测量, 给出有关曲线; 最后分析了几种误差源对干涉仪频率响应函数标定结果的影响及其消除方法。     

谷物害虫图像识别中特征值提取技术的研究

本文阐述了在仓储物害虫分类识别研究中利用计算机数字图像处理技术，对谷物害虫图像的一阶灰度值直方图和图像的目标区域，自动提4取静态仓储物害虫图像的数理统计特征、纹理特征和几何形状特征的主要技术和方法。试验结果表明，该方法可以为谷物害虫的计算机自动模式识别(快速分类)提供稳定的特征参数值，有效地提高了识别率。该方法为仓储物害虫的快速鉴定和分类研究开辟了新的途径。     

激光与红外隐身效果的测量评估方法研究

对光电隐身效果的测量与评估方法做了初步探讨．从隐身材料和隐身设计出发,介绍了光电隐身性能的表征主要技术内容,提出了激光与红外隐身效果的外场测量与效果评估方法．     

Uncertainties in Small-Angle Measurement Systems Used to Calibrate Angle Artifacts

We have studied a number of effects that can give rise to errors in small-angle measurement systems when they are used to calibrate artifacts such as optical polygons. Of these sources of uncertainty, the most difficult to quantify are errors associated with the measurement of imperfect, non-flat faces of the artifact, causing the instrument to misinterpret the average orientation of the surface. In an attempt to shed some light on these errors, we have compared autocollimator measurements to angle measurements made with a Fizeau phase-shifting interferometer. These two instruments have very different operating principles and implement different definitions of the orientation of a surface, but (surprisingly) we have not yet seen any clear differences between results obtained with the autocollimator and with the interferometer. The interferometer is in some respects an attractive alternative to an autocollimator for small-angle measurement; it implements an unambiguous and robust definition of surface orientation in terms of the tilt of a best-fit plane, and it is easier to quantify likely errors of the interferometer measurements than to evaluate autocollimator uncertainty.