中子多重性钚-铀部件质量测量系统及实验进展

为了对核弹头中拆卸下来的和处于库房存储状态的核部件的质量进行无损测量,搭建了一个由32根3 He正比计数管和方型高密度聚乙烯慢化腔体构成的中子多重性探测器,采用8通道电子学处理器件进行中子脉冲信号分析,基于5组252 Cf中子源对中子多重性探测器进行标定,验证了自主开发的标定算法,获取了系统标定参数。分别对6个武器级罐装钚部件,7个罐装铀部件进行中子多重性实验测量,实验分析结果显示:基于点模型修正后的钚部件中子多重性质量测量值与标称值偏差小于1.5%,基于双Am-Li源标定曲线法的铀部件质量测量偏差小于5%。     

基于LabVIEW的砝码自动检定系统设计与实现

针对目前砝码检定工作操作过程复杂、检定效率低等问题,设计了一种基于LabVIEW的砝码自动检定系统。在符合砝码检定规程的情况下,系统实现了检定数据实时采集、数据处理、生成原始记录、管理标准器、查询历史数据和衡器控制等功能。相对现有的砝码检定方法有操作简单、高效、程序移植性好等优点。系统由主控计算机、串口转无线扩展卡、多台衡器设备及相应的标准砝码装置组成。通过使用串口转Wi-Fi模块,系统可实现控制多台衡器设备的需求。实验结果证明,系统运行稳定可靠,采集数据准确,容易扩展,且大幅度减轻了检定人员的劳动强度,在计量检定工作中具有一定的实用和推广价值。     

临界装置实验大厅散射中子分布研究

采用蒙特卡罗方法,通过MCNP5程序对实验大厅内不同散射体产生的散射贡献及散射中子分布进行了计算。结果表明,散射中子强度随离开临界中子源距离先呈减小趋势,在接近大厅墙壁处则出现增加,呈现明显的W形状。同时设计并验证了模拟结果的正确性,结果表明模拟计算与实验测量结果的趋势相同,证明了计算结果的可靠性。     

内部审核在计量体系中的作用

介绍内部审核制度在计量测试工作中的目的和作用，提出了内部审核工作应注意的事项，如内部审核工作计划的完整性，内部审核工作的有效性，管理者工作内容的全面性，以及后续工作的完善性。     

我国粘度计量工作中存在的问题

指出我国粘度计量工作中存在的一些问题，在修订粘度计检定规程，规范标准粘度的名称和有效期以及加强对粘度计检定工作的管理等方面的出了建议，强调了在标准粘度液证书中应给出不同温度下的运动粘度和粘度值，以满足粘度计检定工作的需要。     

Concurrent combined verification: reducing false positives in automated NMR structure verification through the evaluation of multiple challenge control structures

Automated structure verification using ¹H NMR data or a combination of ¹H and heteronuclear single‐quantum correlation (HSQC) data is gaining more interest as a routine application for qualitative evaluation of large compound libraries produced by synthetic chemistry. The goal of this automated software method is to identify a manageable subset of compounds and data that require human review. In practice, the automated method will flag structure and data combinations that exhibit some inconsistency (i.e. strange chemical shifts, conflicts in multiplicity, or overestimated and underestimated integration values) and validate those that appear consistent. One drawback of this approach is that no automated system can guarantee that all passing structures are indeed correct structures. The major reason for this is that approaches using only ¹H or even ¹H and HSQC spectra often do not provide sufficient information to properly distinguish between similar structures. Therefore, current implementations of automated structure verification systems allow, in principle, false positive results. Presented in this work is a method that greatly reduces the probability of an automated validation system passing incorrect structures (i.e. false positives). This novel method was applied to automatically validate 127 non‐proprietary compounds from several commercial sources. Presented also is the impact of this approach on false positive and false negative results. Copyright © 2012 John Wiley & Sons, Ltd.     

JJG 1002-2005旋转黏度计计量检定规程存在的问题探讨

对JJG 1002-2005旋转黏度计计量检定规程存在的问题进行探讨,指出该规程不适合血液黏度计的检定,应重新制订血液黏度计计量检定规程或计量校准规范,以适应医学临床需要.     

啤酒发酵储罐间氧气探测报警器的作用及其检定

简要介绍便携式与固定式氧气探测报警器的区别及其在啤酒发酵储罐间的应用,列出了氧气探测报警器检定的主要技术指标。     

气相色谱仪检定结果的不确定度评定

气相色谱仪检定结果的不确定度主要来源于流速稳定性、柱箱温度稳定性、基线噪声、定量重复性和标准物质进样量的不确定度。以TCD检测器为例进行分析,对气相色谱仪检定结果的不确定度进行评定,相对扩展不确定度为5%。     

Automated structure verification based on 1H NMR prediction

A unique opportunity exists when an experimental NMR spectrum is obtained for which a specific chemical structure is anticipated. A process of Verification--the confirmation of a postulated structure--is now possible, as opposed to Elucidation-the de novo determination of a structure. A method for automated structure verification is suggested, which compares the chemical shifts, intensities and multiplicities of signals in an experimental 1H NMR spectrum with those from a predicted spectrum for the proposed structure. A match factor (MF) is produced and used to classify the spectrum-structure match into one of three categories, correct, ambiguous, or incorrect. The verification result is also augmented by the spectrum assignment obtained as part of the verification process. This method was tested on a set of synthetic spectra and several sets of experimental spectra, all of which were automatically prepared from raw data. Taking into account even the most problematic structures, with many labile protons present and poor prediction accuracy, 50% of all spectra can still be automatically verified without any false positives or negatives. In a blind test on a typical set of data, it is shown that fewer than 31% of the structures would need manual evaluation. This means that a system is possible whereby 69% of the spectra are prepared and evaluated automatically, and never need to be seen or evaluated by a human.