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排序方式: 共有145条查询结果,搜索用时 640 毫秒
71.
72.
A comparative study of different papers published in this special edition of ACQUAL "Accreditaton of RM producers" (see Editorial) is presented. The main question is: Is accreditation the key to guaranteeing the quality of RMs or is it certification? The arguments and different options of the authors are compared and evaluated against existing rules and present practice. In the conclusion options are given which depend on the type of RM producer (namely, laboratory or product certification body), and which could be acceptable to the community of analysts and metrologists, as well as to the market. 相似文献
73.
Measurement and testing are of fundamental importance to science, technology and the economy. There is no science without measurements, no quality without testing and no global market without standards. This article tries to look into the future for the testing community. Based on the anticipated changes in the environment for the testing activities a prediction of the coming technical development as well as acceptance of test results is given. Also the future of accreditation is discussed. 相似文献
74.
利用斑马鱼实验模型,借助液相色谱组合型四极杆Orbitrap质谱联用技术对N-(1-乙氧基羰基-2-甲基丙基)-1-(5-氟戊基)吲哚-3-甲酰胺(5F-EMB-PICA)的体内代谢产物进行分析,筛选潜在代谢标志物。结果表明,在斑马鱼实验模型中5F-EMB-PICA经过代谢共产生13种Ⅰ相代谢产物和6种Ⅱ相代谢产物。Ⅰ相代谢的途径包括酰胺水解、氟戊烷基侧链氧化脱氟、N-脱烷基化、羟基化和酯水解等。Ⅱ相代谢的途径主要为葡萄糖醛酸化。其中酯水解代谢产物(M5.1)响应强度最高,推荐作为5F-EMB-PICA的潜在代谢标志物。为建立生物样品中5F-EMB-PICA的标准检验方法提供相关代谢研究数据,为相关案件的检验鉴定提供技术支持。 相似文献
75.
The applicability of ride comfort standards to off-road vehicles 总被引:2,自引:0,他引:2
P.S. Els 《Journal of Terramechanics》2005,42(1):47-64
The correlation between objective methods for determining ride comfort and subjective comments from crew driving in vehicles were investigated. For objective measurements, the ISO 2631, BS 6841, Average Absorbed Power and VDI 2057 methods were used. The emphasis was on the ride comfort of military vehicles operated under off-road conditions over typical terrains. An experiment was devised and executed in order to obtain both objective and subjective ride comfort values. The correlation between the different methods, measuring positions, measurement directions and calculation methods was determined. It is concluded that all the methods can be used to specify and evaluate ride comfort, but that acceptable ride comfort limits vary. The vertical measurement direction was dominant. Due to the frequency content of the measured acceleration, the specific weighing curve is not very important for the type of vehicle considered. 相似文献
76.
基于主列筛选的动态测试传感器配置方法研究 总被引:1,自引:0,他引:1
动态测试是获取结构真实动态特性的重要手段之一,传感器配置对于保证动态测试数据的信息量有着重要的影响. 尤其是对以试验模态分析为目标的动态测试,传感器配置对于模态分辨率更是决定性因素. 在振型独立性的基础上,提出了一种基于主列筛选的传感器配置方法. 与现有的逐步累积类或逐步消减类方法相比,该方法无需迭代,一次选择所有测试自由度,计算量小. 为了量化比较传感器配置的效果,定义了4个度量指标. 采用卫星天线模型进行了数值仿真,结果验证了基于主列筛选的传感器配置方法的有效性. 相似文献
77.
实验室质量体系和体系文件的策划 总被引:3,自引:2,他引:1
简述了实验室质量体系所含的要素和建立质量体系的一般过程,以及质量体系文件的组成和编写、编辑文件的要点。 相似文献
78.
Repetitive testing is a fairly common practice in the final testing stage of a chip manufacturing. Decisions on setting initial lot size and the number of testing repetitions are crucial to the effectiveness of the testing process. The task of setting optimal parameters for a testing process is often difficult in practical situations due to uncertainties in both incoming product yield and testing equipment condition during the testing process. In this paper, we investigate a repetitive testing process where the testing equipment may shift randomly from an in-control state to an inferior state during the testing process which, correspondingly, results in different testing errors. We develop a quantitative model that helps us to find optimal test parameters that maximizes system performance. Based on the model, we performed extensive numerical experiments to test the effects of incoming product defective rate, testing equipment shift rate, especially, type II testing errors on decision and system performance. We find that test equipment condition may significantly affect the optimal decisions on the number of test repetitive and initial testing batch size. Further, we find that, while a small type II testing error may have negligible negative effect of system performance, the effect increases as the error or the incoming product yield increases. The results of this research may potentially provide practitioners with insights and a quantitative tool for designing an efficient repetitive testing process. 相似文献
79.
《Analytical letters》2012,45(1):111-123
ABSTRACT Although diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is mainly used for powdered solid samples, it was found to be highly effective for the analysis of certain gemstones. Small amounts of oils and resins used to fill cracks and fissures in substandard (included) emeralds and rubies could be detected. Because of their very low levels, these organic adulterants can be difficult to detect by measurement of the infrared transmittance spectrum. Rubies have a significantly larger “window-of-detection” for organic clarifying agents than do emeralds. In some cases the spectral information was sufficient to identify the oil or polymer resin. Emeralds that were treated over 20 years ago are still easily identified. The position of the emerald or ruby in the sample holder can affect the intensity of C-H and O-H stretching frequencies as well as those brands characteristic to the gemstones. 相似文献
80.