High-accuracy Measurement Techniques Research Articles

High-Accuracy Determination of Potassium and Selenium in Human Serum by Two-Step Isotope Dilution ICPMS.

A high-accuracy measurement technique for determining potassium and selenium in human serum was developed by using two-step Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry (ICPMS) in this research. A more accessible method of the quadrupole ICPMS was employed in this research to achieve an equally high accuracy which had been achieved by a much more expensive method, namely, high-resolution sector field ICPMS (SF-ICPMS), with a comparatively easy and simple operation. In addition, we have evaluated the uncertainty of this method. The results showed that the determination limits of potassium and selenium in serum were 0.8 mg/kg and 2.7 μg/kg, respectively, and the precision for both measurements was lower than 0.2% and 0.7%. The measurement, when employed to measure potassium and selenium in standard materials NIST956D, NIST909C, and GBW09152, had caused a maximum deviation of less than 0.9%, within the stated uncertainty range of standard materials. The RELA international inter-laboratory comparisons of potassium in serum in 2018 conducted by our laboratory also yielded a satisfactory result.

The elastic properties of an actively controlled piezoelectric transducer: Measurement, analysis and tuning

We report on the development of a method for the measurement of the effective stiffness of a piezoelectric transducer which is bonded to a vibration control system and operated using an approach known as active elasticity control (AEC). Using high-accuracy measurement techniques it is shown that the effective stiffness of the transducer can reach negative values in a certain frequency range, when a suitable active shunt circuit is connected to its electrodes. Extensive analysis proves the consistency of mechanical and electrical measurements of the dynamically loaded piezoelectric transducer compared with the AEC model. A method which allows the computation of adjustments to the active shunt circuit based on the vibration control device's measured mechanical transfer function is developed. The applicability of the method to a real vibration control system is also demonstrated.

Sampling and Estimation of Pairwise Similarity in Spatio-Temporal Data Based on Neural Networks

Increasingly fast computing systems for simulations and high-accuracy measurement techniques drive the generation of time-dependent volumetric data sets with high resolution in both time and space. To gain insights from this spatio-temporal data, the computation and direct visualization of pairwise distances between time steps not only supports interactive user exploration, but also drives automatic analysis techniques like the generation of a meaningful static overview visualization, the identification of rare events, or the visual analysis of recurrent processes. However, the computation of pairwise differences between all time steps is prohibitively expensive for large-scale data not only due to the significant cost of computing expressive distance between high-resolution spatial data, but in particular owing to the large number of distance computations ( O ( | T | 2 ) ) , with | T | being the number of time steps). Addressing this issue, we present and evaluate different strategies for the progressive computation of similarity information in a time series, as well as an approach for estimating distance information that has not been determined so far. In particular, we investigate and analyze the utility of using neural networks for estimating pairwise distances. On this basis, our approach automatically determines the sampling strategy yielding the best result in combination with trained networks for estimation. We evaluate our approach with a variety of time-dependent 2D and 3D data from simulations and measurements as well as artificially generated data, and compare it against an alternative technique. Finally, we discuss prospects and limitations, and discuss different directions for improvement in future work.

Identification of Tension Distribution of Thin Plate Using Vibration Characteristics (Identification Method of Tension Distribution Considering Added Mass Effect of Air)

A high-accuracy measurement technique for plate tension distribution on the process line would potentially lead to improved steel, aluminum and copper plate qualities. We propose an identification method by using natural frequencies and vibration modes, which are related to tension distributions of thin plate. In this paper, a new tension identification method in a thin plate using characteristics of vibration is investigated. We develop a simplified dynamic model of thin plate, and tension distribution is modeled by springs. A simplified model spring constants are obtained by the least-squares method to minimize the difference between a simplified model modal parameters and the given values. We apply the proposed identification method to a thin aluminum plate based on FEM analysis results considering added mass effect of air. As a result, it is shown that identified tension distributions well correspond to the FEM results.

Identification of Tension Distribution of Thin Plate Using Vibration Characteristics

A high-accuracy measurement technique for plate tension distribution on the process line would potentially lead to improved steel, aluminum and copper plate qualities. We propose an identification method by using natural frequencies and vibration modes, which are related to tension distributions of thin plate. In this paper, a new tension identification method in a thin plate using characteristics of vibration is investigated. We develop a simplified dynamic model of thin plate, and tension distribution is modeled by springs. A simplified model spring constants are obtained by the least-squares method to minimize the difference between a simplified model modal parameters and the given values. We apply the proposed identification method to a thin aluminum plate based on FEM analysis results. As a result, it is shown that identified tension distributions well corresponded to the FEM results.

Calibration Technique for Accurate Diode to Diode Spacing Measurements

Diode to diode spacing is critical for high resolution print quality in electrophotographic printing. Small errors in spacing, smaller than the accuracy of current measurement equipment, can create beats in halftone screens leading to pronounced banding defects. High accuracy measurement techniques using mathematical analysis of lower resolution data have been reported. These techniques are contingent on accurate calibration of spatial quantum efficiency of measurement cameras which in turn depend on light/bright field irradiance calibration. An inexpensive but uniform light source design and the resulting data for light field calibration are described. Dark field calibration is also discussed, but has a smaller impact on the diode to diode spacing measurement.

150 振動法による薄板の張力分布同定技術の開発

A high-accuracy measurement technique for plate tension distribution on the process line would potentially lead to improved steel, aluminum and copper plate qualities. We propose an identification method by using natural frequencies and vibration modes, which are related to tension distributions of thin plate. In this paper, a new tension identification method in a thin plate using characteristics of vibration is investigated. We develop a 2-D dynamic model of thin plate, and tension distribution modeling by springs. A 2-D model spring constants are obtained by the least-squares method to minimize the difference between a 2-D model modal parameters and the given values. We apply the proposed identification method to a thin aluminum plate based on FEM analysis results. As a result, it is shown that identified tension distributions well corresponded to the FEM results.

Dislocation Nucleation and Interaction Under Nanoindentation in Single Crystalline Al and Cu (Simulations by Molecular Dynamics)

Recent advances in miniaturization and high-accuracy measurement techniques have allowed us to measure the mechanical properties at the nanometer scale. Nanoindentation has been widely used because of its applicability under ambient conditions. Unstable displacement burst, that is abrupt growth of indent depth after homogeneous elastic deformation observed in crystalline materials, is one of the unique plastic deformation (nanoplasticity). In the present paper, we perform a series of atomistic simulations of nanoindentation in single crystalline Al and Cu to analyze the critical state for dislocation nucleation and interaction between dislocations beneath the indenter. Referring Hertzian solution based on the isotropic linear elastic theory, we attentively disscuss the anisotropic effect and the nonlinear behavior under nanoindentation. Consequently, it is found that incipient yield process is strongly related to the triaxial stress state created beneath the indenter, and that energetically unfavorable interactions accompanied with cross slip induce the formation of prismatic dislocations.

A new traceability system in Japan

In 1993, the measurement law was revised and enacted in Japan. The old law had provided only the use of legal metrology units and the approval and verification systems for measuring equipment. The new one has added the provision of a traceability system to match the needs for a high accuracy measurement technique and international mutual recognition. In the Electrotechnical Laboratory (ETL), the national standard of sound-pressure level has been established and maintained in an audible frequency range. The type approval test and verification of sound level meters have been carried out in the Japan Quality Assurance Organization (JQA). Now, in conformity with the law, ETL has started to construct the new traceability system for the acoustical standards in cooperation with JQA. An outline, is made of the traceability system in Japan and of the newly constructed pressure calibration systems for laboratory standard microphones.

High-accuracy measurement techniques for capacitance transducers

Capacitance transducers are used in different applications such as measurement of vibrations, displacement, pressure, fluid density and so on. Depending on the application, transducers can have both floating electrodes, or in some cases, one earthed. Shielding techniques introduce parasitic capacitances, the compensation of which requires methods ranging from measuring configurations for floating capacitances up to more complicated techniques when one of the two transducer electrodes is earthed. The authors present an instrument employing an auto-balancing technique via a negative feedback that zeroes the static value and the very slow fluctuations of both the transducer and the stray capacitances, allowing high signal amplification and thus high sensitivity. The measuring circuit is composed essentially of a phase-sensitive detector and an integrating feedback path. A sensitivity of 1 mV fF-1 and a measurement range up to 10 pF is obtained, while an equivalent capacitance noise of 0.5 fF has been measured in the presence of a three-decade bandwidth.

First sea trial of 1.5- mu m submarine optical fiber cable

The first sea trial of submarine optical fiber cable using dispersion-shifted fibers is described. The discussion covers the fiber structural design, cable manufacturing results, fiber splicing, cable laying results, and a high-accuracy measurement technique for optical loss and chromatic dispersion. The results demonstrate the feasibility of long-span, high-capacity 1.5- mu m submarine optical fiber cable.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>