Abstract: Bayesian statistics provides a powerful tool for the analysis of data. The methods are flexible enough to permit a realistic modelling of complex measurements. Prior information about the experiment, as well as knowledge from other sources can be used in a natural way. All relevant quantities concerning the measurement, as e. g. the expected values and their associated uncertainties are obtained from probability density functions. Bayesian data analysis strictly follows the rules of probability theory, thus ensuring that the procedure is free of inconsistencies and is in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM).
Abstract: . This study presents the dynamic calibration of pressure sensors using a developed liquid step wave generator. This approach is sufficient to display the transient response of pressure sensors in the time and frequency domains and it depends on the performance of pressure generators. In this study, the liquid step wave generator was developed via a reformed spool valve generating a liquid step wave with a short rise time that current generators have not achieved so far. A small sensing cavity, where maintains the liquid step wave, and a contact seal were adopted herein to limit the pressure transient of the fluid in the generator, such that the rise time and the bandwidth of the liquid step wave can reach 30.0 µs and 10.4 kHz. The experimental results not only display the performance of the liquid step wave generator, but also reveal the dynamic characteristics of three different test pressure sensors using the developed liquid step wave generator.
Abstract: A number of new problems of measurement assurance of computerized measuring instruments at the stage of development, production and operation stages are discussed. Possible solutions are outlined taking into account the experience of the D.I. Mendeleyev Institute for Metrology.
Abstract: The article describes a patented method of displaying objects that secures natural visual perception of the objects displayed without distortions in their scaling relation and the dimensional depth. The author considers a group of linear perspectives with homographic function to display/map 3D visual scenes. The article also describes matrices for projective transformation.
Abstract: Correlation method for processing dynamic light scattering patterns observed when laser radiation passes through liquid media was developed. The method is based on procedure of spatial averaging of the data contained measured values of correlation functions of intensity of light scattered by moving small particles. The method allows one to measure particles diameters from 30 to 750 nm with measurement error less then 10%. The method makes it possible to decrease correlation functions measurement time down to 1 ms and provides opportunity to carry out measurements for different scattering angles simultaneously. The method offers a way of recognizing speckle pattern transformations caused by harmonic, translatory and Brownian motions of particles, and allows one to register influence of uncontrolled forces such as monochromatic and wideband acoustic fields upon particles size measurements results.
Abstract: Methods for measuring the resonant frequencies and visualizing the motion of the Pb(Zr0.5Ti0.5)O3 microcantilever are investigated. Considering the two-segment structure of the microcantilever, a self-exiting self-sensing method is proposed to obtain the fundamental resonant frequency. An optical system consisting of light microscope, CCD camera and video card is established to visualize the first two vibration mode shapes. The theoretical, measured and visualized first resonance of one micocantilever is 17.28 kHz, 17 kHz and 17.8 kHz, respectively. A theoretical second resonance of 84.16 kHz is seen at 71.9 kHz. The proposed method is valid for measuring and visualizing low resonances of active micro structure.
Abstract: The problem of reducing measurement errors of surface microrelief with nonuniform scattering properties using white-light interferometer was discussed. Adaptive algorithm of thresholding which allows us to set optimal threshold in every point of measuring surface was proposed. Application of this algorithm of threshold choice allows increasing dynamical range of interference detection more than in 10 times. The dependences of scanning interferometer resolution on differentional interferogram thresholding have been discussed.