[en] For monitoring the position and shape of fast moving and, especially, rotating objects such as turbo machine rotors, contactless and compact sensors with a high measurement rate as well as high precision are required. We present for the first time, to the best of our knowledge, a novel laser Doppler sensor employing a single fan-shaped interference fringe system, which allows measuring for the position and shape of fast moving solid bodies with known tangential velocity. It is shown theoretically as well as experimentally that this sensor offers concurrently high position resolution and high temporal resolution in contrast to conventional measurement techniques, since its measurement uncertainty is, in principle, independent of the object velocity. Moreover, it can be built very compact, because it features low complexity. To prove its operational capability and its potential for practical applications, radial and axial shape measurements of rotating bodies are demonstrated in comparison with triangulation. An average position resolution of about 2 μm could be achieved

[en] This work is devoted to an evaluation of the integral coefficients of neutron resonances directly from resonance parameters, which enables the evaluation of individually distinct single-resonance integrals. Individually distinct single-resonance integrals are useful when investigating the statistical nature of resonance distribution, the role of the neutron flux shape parameter, applications in nuclear reaction physics, isotope synthesis in reactors and astrophysical entities, activation analysis, and the science of nuclear materials. The present R-matrix treatment comprises exact expressions for the Breit–Wigner resonance representation and approximate expressions for the Reich–Moore representation; the latter is used to avoid the complicated techniques used for matrix inversion. The analytical formulae are used to evaluate the necessary integral neutron coefficients directly from spectroscopic nuclear data. Using the analytical formulae, the resonance integrals and the effective resonance energy can be taken into consideration for any specific values of epi-thermal shape parameter. In addition, the atomic displacement densities can be computed with variable threshold energies for atomic displacements. A Fortran code, NEURESINT, designed to perform these calculations is given in the manuscript’s supplementary material available online at stacks.iop.org/PS/94/065301/mmedia. The code is used to compare integral coefficients among different versions of evaluated nuclear data files. The present approximation gives thoroughly consistent results with the reported values of integral parameters. Our results showed that care must be taken when applying the methods and code mentioned in the present work to some isotopes, especially actinides having a resonance level close to the epi-cadmium cutoff energy at 0.55 eV, in which much smaller cutoff energy value, as low as 0.1 eV, needs to be used. (paper)

[en] Published in summary form only

[en] A new type of four-path interferometer is proposed to investigate the nature of the ‘discontinuous trajectories’ of a photon. Our derivation shows that the absence of ‘weak traces’, which makes the trajectories of the photon seem to be discontinuous, is actually due to the multi-path interference, and cannot be a strong criterion to say ‘The photon has not been there.’ The presence of the weak traces is a sufficient but not necessary condition for the fact that the photon has been the corresponding places. Moreover, the propagating paths of the photon must always be continuous. (paper)

[en] A method is proposed for recording a series of double-exposure holograms in one recording medium by rotating the medium between the recording cycles and reconstructing the interference patterns characterising a change in the object state in time. The conditions for obtaining interference patterns in fringes of infinite and finite widths are considered. The results of experiments on recording a series of nine double-exposure holograms in an FG-690 holographic film are presented. (holography)

No abstract available

No abstract available

[en] Published in summary form only

No abstract available

[en] We demonstrate the temporal Talbot effect for trapped matter waves using ultracold atoms in an optical lattice. We investigate the phase evolution of an array of essentially non-interacting matter waves and observe matter-wave collapse and revival in the form of a Talbot interference pattern. By using long expansion times, we image momentum space with sub-recoil resolution, allowing us to observe fractional Talbot fringes up to tenth order.