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51.
52.
Stanley Rasberry 《Accreditation and quality assurance》2001,6(6):252-256
Traceability implies comparison of the results of measurements, or comparison to national or international measurement standards.
One of several approaches that have been used in chemistry to provide for such comparisons is distribution of proficiency
evaluation materials which have been measured by a reference laboratory. A newer approach is based on receipt and measurement
at a reference laboratory of materials that have been produced and analyzed by other laboratories. Traceability concepts and
approaches to realization will be described together with discussion of the relative merits of various approaches. Extension
into metrological fields other than chemistry will also be explored.
Received: 14 November 2000 Accepted: 11 December 2000 相似文献
53.
K. S. Dharmsaktu Arvind Kumar Renu Tripathi K. Singh 《Optics and Lasers in Engineering》2000,34(3):191
A technique has been proposed to analyze small in-plane component of vibrations by measuring the fringe shift, and analysing the correlation output of captured vibrating Young's fringes with a photorefractive correlator. Fringes are formed due to interference between the reconstructed speckled beam recorded for stationary object beam, and vibrated speckled beam transmitting through a BaTiO3 crystal after introducing a small shift in the diffuser position. The correlation peak intensity is affected due to mismatch of vibrations between two piezo-mirrors in the object beam. High correlation output gives an indication of the frequency matching of known reference and unknown vibrations, thus giving information on the frequency of vibration. Vibration amplitudes of the order of a wavelength of light have been measured by counting the number of fringes passing past a line in the observation plane. 相似文献
54.
A stereoscopic digital speckle photography system for 3-D displacement field measurements 总被引:7,自引:0,他引:7
Stereoscopic digital speckle photography offers a technique to measure object shapes and 3-D displacement fields in experimental mechanics. The system measures the displacement of a random white light speckle pattern, which somehow is present on the object surface, using digital correlation. This paper describes a general physical model for stereo imaging systems. A camera calibration algorithm, which takes the distortion in the lenses into account, is also presented and evaluated by real experiments. Standard deviations of small deformations as low as 1% of the pixel size for in-plane deformations and 6% of the pixel size for the out-of-plane component are reported. Using the calibration algorithm described, the main source of errors is random errors originating from the correlation algorithm. 相似文献
55.
Alessandro Candeloro Sholeh Razavian Matteo Piccolini Berihu Teklu Stefano Olivares Matteo G. A. Paris 《Entropy (Basel, Switzerland)》2021,23(10)
Active optical media leading to interaction Hamiltonians of the form represent a crucial resource for quantum optical technology. In this paper, we address the characterization of those nonlinear media using quantum probes, as opposed to semiclassical ones. In particular, we investigate how squeezed probes may improve individual and joint estimation of the nonlinear coupling and of the nonlinearity order . Upon using tools from quantum estimation, we show that: (i) the two parameters are compatible, i.e., the may be jointly estimated without additional quantum noise; (ii) the use of squeezed probes improves precision at fixed overall energy of the probe; (iii) for low energy probes, squeezed vacuum represent the most convenient choice, whereas for increasing energy an optimal squeezing fraction may be determined; (iv) using optimized quantum probes, the scaling of the corresponding precision with energy improves, both for individual and joint estimation of the two parameters, compared to semiclassical coherent probes. We conclude that quantum probes represent a resource to enhance precision in the characterization of nonlinear media, and foresee potential applications with current technology. 相似文献
56.
Emmanuel Nolot Yann Mazel Jean-Paul Barnes Chiara Sabbione Gabriele Navarro Agnes Tempez Sébastien Legendre 《Surface and interface analysis : SIA》2020,52(12):895-899
We demonstrate the potential of using plasma profiling time-of-flight mass spectrometry (PP-TOFMS) to accelerate process developments for phase-change random access memory (PCRAM) applications, which require advanced materials with composition-driven properties. We assess the performances of PP-TOFMS for the chemical depth-profiling of GeSbTe phase change materials, first after deposition steps to investigate the top surface layer and the incorporation of silicon into the amorphous matrix, then after the thermal annealing step to refine in situ capping strategies, and finally in close loop with etching process steps. Comparison of reference-free semiquantitative PP-TOFMS analysis based on ion beam ratio with Rutherford backscattering spectrometry shows remarkable agreement (~10% relative). PP-TOFMS proves to be a fast screening tool, which allows process monitoring and selection of samples that indeed need more complex analysis. 相似文献
57.
The metrology of Coulombic efficiency (CE) is widely used for the qualification of rechargeable batteries particularly in assessing their state of health and the expected lifetime. The quantity of CE is conventionally defined as the ratio of the electric charge capacity in one round-trip cycle of discharge and charge of a battery. For better diagnosis of the health, failure and lifetime of rechargeable batteries, it is desirable to expand the traditional CE of the round-trip electric charge to including that of the round-trip CE of ionic charges as well as those of single trip CEs of ionic/electric charges for charging and electric/ionic charges for discharging. To enable such expansion, in operando ion metrology is needed. For the mainstream technology of lithium-containing batteries, neutron depth profiling is one of the techniques suited for Li ion metrology. In this report, we demonstrate the application of in situ neutron depth profiling to expanding the metrology of Coulombic efficiencies to include all four CEs. The methodology of expanded CE is exemplified using measurements and analyses on a model battery of LiFePO4 vs. Li. 相似文献
58.
59.
介绍了采用PIN硅光电二极管作光接收器件实现的一种被动式实时测温系统。该系统主要由光学接收系统、信号放大与处理系统及显示系统三部分组成。从系统的相对测温灵敏度及探测器的温度分辨力与波长间的关系出发,结合大气对红外辐射的透射特性,确定了系统的工作波长;从系统的抗反射辐射能力出发,并结合探测器的最小可探测光功率要求,确定了系统的波长带宽。从P1、P2的测量不确定度出发,讨论了待测目标的发射率及温度的测量精度。结果表明,当λ=0.80μm、Δλ=20nm时,在测温范围600~2500℃内,系统的测温不确定度优于0.3%,满足设计要求。 相似文献
60.
Accuracy and sensitivity of a hole drilling and digital speckle pattern interferometry combined technique to measure residual stresses 总被引:4,自引:2,他引:2
This paper reports on the accuracy and sensitivity of digital speckle pattern interferometry (DSPI) when it is combined with the hole drilling technique for measuring residual stresses. The in-plane displacement field generated by the introduction of a small hole is determined using an automated data analysis approach. This method is based on the calculation of the optical phase distribution through a phase-shifting method and the application of a robust iterative phase unwrapping algorithm. It is experimentally demonstrated that residual stresses can be measured with a relative uncertainty of 7.5%. It is also shown that the minimum value of residual stress that can be determined with the DSPI and hole drilling combined technique is about 10% of the yield stress of the material. 相似文献