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The high measurement accuracy in dynamic tension testing is required for designs and numerical simulations based on the accurate modeling of stress–strain relations at various strain-rates. The non-coaxial Hopkinson bar method (NCHBM) is one of the recently proposed methods for dynamic tension tests. In this study, the direct measurement of both stress and strain was conducted by using the strain gauges affixed on the special specimen with load cell part. The stress–strain relations obtained by this revised NCHBM were compared with those obtained by the normal NCHBM. In order to verify the experimental results, some numerical models were examined by using the FEM code LS-DYNA, in which the whole finite-element model of the apparatus and the plate-type specimen were made in detail. Furthermore, new appliances for fixing specimen were examined by experiment. The target material employed in this study is SUS316.

Using a simple signal processing approach and taking into account the finite linewidth of each longitudinal mode in a mode-locked laser, we investigate the measurement accuracy of the mode-locked laser and analyze the mode-locked pulse train coherence characteristic. Results show that the measurement accuracy in the interference between two mode-locked pulses with the same repetition rate depends on mode-locking stability rather than pulse duration. Mode-locking stability can be achieved by reducing the longitudinal mode linewidth. The mode-locked pulse amplitude is modulated by a modulation envelope function, rather than illimitably continuous pulses because of the finite linewidth of the longitudinal modes. A mode-locked laser emits numerous pulse modulation envelopes one by one and each pulse modulation envelope is described by the same function. Powerful ways are proposed to decrease the linewidth and improve mode-locking stability and measurement accuracy.

Correlation measurement is an effective way of measuring noise components with a magnitude smaller than the system noise. The accuracy of such measurement depends on the system bandwidth, the magnitude of the noise to be measured compared to the system noise and the measurement time. The accuracy can be improved by increasing the measurement time. A method of estimating the measurement time required for a desired level of accuracy for a given system noise and bandwidth is presented.

This paper reviews the interpretation of impedance and capacitance spectra for different capacitor technologies and discusses how basic electrical characteristics can be inferred from them. The basis of the interpretation is the equivalent circuit for capacitors. It is demonstrated how the model parameters, such as capacitance and equivalent series resistance, can be extracted from the measured spectra. The aspects of measurement accuracy are exemplarily discussed on the measured spectra.

The high measurement accuracy in dynamic tension testing is required for designs and numerical simulations based on the accurate modeling of stress–strain relations at various strain-rates. The non-coaxial Hopkinson bar method (NCHBM) is one of the recently proposed methods for dynamic tension tests. In this study, the direct measurement of both stress and strain was conducted by using the strain gauges affixed on the special specimen with load cell part. The stress–strain relations obtained by this revised NCHBM were compared with those obtained by the normal NCHBM. In order to verify the experimental results, some numerical models were examined by using the FEM code LS-DYNA, in which the whole finite-element model of the apparatus and the plate-type specimen were made in detail. Furthermore, new appliances for fixing specimen were examined by experiment. The target material employed in this study is SUS316.