本刊讯 近日,中国合格评定国家认可委员会(CNAS)秘书处批准并正式发布了《中国计量科学研究院认可方案》(CNAS-CL01-S01:2023,以下简称"认可方案"),并就修订内容进行对照说明.新版文件于2023年1月1日正式发布实施,发布文件在中国计量科学研究院官方网站同步更新.

液体静力称量法是固体密度测量最常用也是测量准确度较高的一种方法.基于阿基米德原理,研究了表面张力对固体密度测量结果的影响.实验选取纯水和纯酒精2种液体作为工作介质,采用一套高准确度液体静力称量装置测量同一固体样品的密度值.实验结果表明,在表面张力小的液体(纯酒精)中固体样品密度测量结果的分散性明显优于在表面张力大的液体(纯水)中固体样品密度测量结果的分散性,为今后提高固体密度测量准确度提供参考方向.

以相移干涉测长为应用背景,提出了一种基于“机械扫描”的相移测长方法.利用超高弹性石英材料研制出了干涉测长所需的单体3路相移装置,并利用该相移装置建成了相移测长装置,成功地将位移传感器的量值在线溯源到光学频率标准,从而实现了对3路相移的准确测量.介绍了一种引入步长控制误差的“新五幅相移”实现相位解算方法,算法准确度达到0.01％.对不确定度的定量分析结果表明,基于该机械扫描式相移技术构建的绝对长度测量系统准确度可达0.5 nm.

A new method to determine the density of hydrometer is presented by the associated ways of exact mathematic calculation and approximation method of neglecting the minor error source. Based on the characteristic of that the stem scale is easier to control to be the same level of liquid surface than to evaluate the position against liquid level, the hydrometer is weighed in the liquid when the stem scale is in the same level of liquid surface. It is not only to avoid reading error, but also do not need change the liquid in the measurement of full density range. It is a valueable and propagable way in the accurate measurement of the hydrometer density.

JJG 999-2005<称量式数显液体密度计>(以下简称数显密度计)使用标准玻璃浮计检定数显密度计,该方法存在一定的不足之处,使用砝码代替标准玻璃浮计检定数显密度计则可以避免这些弊端,具有使用标准玻璃浮计无法比拟的优越性.通过对砝码检定数显密度计测量结果的不确定度分析可知,该方法是可行的.

The diameter of a 1-kg silicon sphere needs to be accurately measured to determine the volume and density to investigate the Avogadro constant. The diameter of the silicon sphere was measured using phase-shifting interferometry with an algorithm with an accuracy of 0.01% of the phase period. The algorithm accurately analyzes the phase map without strict positioning of the phase-shifting step. A phase-shifting generator was then designed to accurately determine the diameter. The distances between the two Etalon plates were measured with a phase shift of 1 mu m with the gaps between the surface of the silicon sphere and each Etalon plate measured with a phase shift of 2 mu m by the mechanical scanning method. The Etalon cavity length changes by only 0.1 nm when the pressure is released. The combined standard uncertainty in the silicon sphere diameter is then less than 2.3 nm.

<正>振动式密度仪广泛应用于石油化工、香精香料、化妆品、制酒及饮料、食用油、调味品、烟草、商检、电子工业等领域,由于其使用方便、量程范围宽、测量快速准确、用样少、克服了玻璃浮计测量用液多、易碎的缺点,近几年发展迅速,用量呈逐年递增趋势,且已列入新颁布的《密度计量检定系统》中。

介绍了液体密度标准以及用液体密度标准测量固体体积和真空质量的方法和计算公式.

Based on the improved five-interferogram algorithm,a novel interferometer with special etalon is developed.The distance between two standard surfaces of this etalon can be changed by pressure in vertical direction to realize phase shift and can be come back with accuracy better than 0.1 nm when the pressure is free. The measurement standard uncertainty of diameter of the silicon sphere is better than 3 nm and measurement standard uncertainty of the silicon crystal density is(1×10~(-7)).

固体密度基准的准确度主要取决于对单晶硅球直径的准确测量. 为了准确测量硅球直径, 针对传统五幅相移算法之不足, 提出了"改进型五幅算法", 在保持该算法高准确度特点的同时, 通过将技术上难以实现的步长"准确控制"(理论上要求绝对准确)转换成步长测量问题, 解决了该算法在精密测长中的技术难题; 在算法突破的基础上, 利用"压力扫描"原理设计出"腔长可变式"法-珀标准具, 建立了一套与国外同行相比技术原理新颖、提高潜力较大的相移法精密测长系统. 该测量系统对硅球直径的测量准确度优于3 nm; 单晶硅密度的测量不确定度达到1×10-7.

The accuracy of solid density primary standard is decided mainly by the accuracy of the diameter measurement of silicon sphere. With traditional five-interferogram algorithm to unwrap phase for diameter measurement, the phase steps should be equal to π/2 exactly, but this is almost impossible to achieve in nanometer positioning technique. In order to overcome this defect, we have derived an improved five-interferogram algorithm, which not only keeps the high accuracy of traditional five-interferogram algorithm, but also does not require absolute equal step to unwrap phase. Instead, the improved five-interferogram algorithm only needs measuring phase shifting. Based on the improved algorithm, we have developed a novel interferometer with special etalon, and the cavity length of this etalon can be changed by pressure from vertical direction to realize phase shifting. The accuracy of this interferometer is better than 3 nm and can be improved in future research.

介绍了液体静力称量法测量液体密度的原理并给出液体密度的计算公式,对影响测量结果的各种因素作了详细的分析,并对各个分量所引入的不确定度进行了数值计算,得出液体密度最终测量结果的合成标准不确定度。

Although the traditional five-bucket phase-shifting algorithm possesses excellent accuracy,itisn't used in the practical length measurement because of the strict conditions of equal step length of phase shifting.Based on two-beam interference principle,a corrected five-bucket phase-shifting algorithm which possesses high accuracy with an arbitrary phase step in range of 10 nm is present.With the numerical simulation,it shows that the accuracy of the corrected algorithm is better than 0.001 phase period when the measuring error of the phase step is 1 nm and the measuring error of the signal is 0.1%,besides that,this algorithm does not need accurate equal step length of phase shifting.With higher reliability and higher accuracy,the corrected five-bucket phase-shifting algorithm is very valuable for the precision length measurement.