X-ray waveguides can compress an incident beam for microscopy applications above 8 keV photon energy to sizes smaller than 100 nm in one dimension, a range which is not routinely accessed with other x-ray optics (e.g., Fresnel zone plates). Beryllium, because of its low absorption, is expected to provide the highest intensity gain. Measured gains for a beryllium waveguide of 74 nm thickness exceed values of 100 at 13 and 20 keV photon energy, which is an improvement by an order of magnitude compared to previously reported performances. The same object works also at 8 keV with gain 43.

The Kolka Glacier, which rushed down the Genaldon valley on September 20, 2002 (North Ossetia), is now recovering after this catastrophe. One of the most important ways to predict a new disaster is to determine the rate of ice accumulation of the new glacier and to monitor the glacier volume regularly, since its trigger mechanisms have not yet been fully studied. Recent changes of the Kolka Glacier were investigated by means of ground stereoscopic photography. The field works were carried out in 2014, 2016 and 2017. Shooting was made manually with a digital camera Canon 5D Mark II (without using a tripod) at arbitrary points, the distance between which did not exceed 100 m. The reference points were placed on the elevated relief forms on the glacier surface and coordinated by a differential GNSS receiver in the "fast static" mode. Laboratory processing of the photos was performed using Agisoft Photoscan software in automatic mode, except for the procedure of identification of reference points on stereo images. The processing made possible to obtain digital models of the glacier surface in Geo-TIFF format, the vertical error of which amounted to 0.7 m, while the horizontal one – 2.3 m. In 2014–2017, the maximal increase in height of the surface (up to 30 m) was recorded in the low part of the glacier tongue that was the result of advancing of the Kolka front along the ice-free surface. Mean annual increase in the surface elevation was equal to 2.2 m/year. Lowering of the surface in some areas may be explained by the slowing-down of the glacier flow rate, which led to the appearance of thermokarst. The glacier volume increased by 7.4±0.7 million m3. As a result, the glacier tongue advanced by 50–70 m. Average over 2014–2017 increasing in the surface elevation (2.2 m/year) was slightly smaller than in 2004–2014 (3 m/year). Quick growth of the Kolka Gacier contrasts sharply with decreasing of volume of the representative Caucasus, Djankuat and Garabashi, over the same period.

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The improved spatial coherence of a synchrotron radiation beam was shown experimentally to stimulate additional diffuse scattering of x rays diffracted from x-ray multilayer mirrors. Although the large-scale (tens of microns) roughness does not affect Bragg diffraction from multilayers, its presence causes phase shifts at the wave packet front. This leads to partial decay of the coherent wave packet and creates additional diffuse scattering. Additional scattering from this mechanism was observed at angles of incidence corresponding to the Bragg and Kiessig maximum angles. The properties of this scattering caused by large-scale roughness, observed due to improved x-ray beam spatial coherence, were shown experimentally to be different from those of diffuse scattering previously reported when the incoming or outgoing angle is equal to the Bragg angle. Typical breaks in the diffuse scattering intensity due to the standing-wave effect are absent, and there is obvious asymmetry of the diffuse scattering cross section around the incoming and outgoing angles. Due to the small angle of incidence, the coherently irradiated area has very different dimensions parallel and perpendicular to the beam, which leads to the observed scattering being concentrated in the specular diffraction plane defined by the incident and reflected wave vectors.

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The mathematical model that describes the local heating of biological tissues by optical radiation is introduced. Changes of the electric properties of biological tissues in such process can be used as a reliable tool for analyzing heating and damage degrees of tissues.

Triple‐axis X‐ray diffractometry was used to study diffuse scattering from an AlAs/GaAs superlattice grown on an [001]‐oriented GaAs substrate by molecular beam epitaxy. Reciprocal‐space maps were obtained around the 002 reflection from the superlattice and its low‐angle first‐order satellite. The data obtained reveal quasi‐Bragg diffuse‐scattering sheets caused by conformal behavior of interfacial roughness as well as amplification of diffuse scattering when the incoming or outgoing angle is nearly equal to the Bragg angle of the superlattice or substrate. The observed features of diffuse‐scattering fine structure are explained within the framework of the distorted‐wave Born approximation. Nevertheless, this approximation is shown to be incorrect for quantitative analysis of diffuse scattering. In particular, the observed domination in intensity of the incoming Bragg features over the outgoing ones is shown to reflect the decay rate of the coherent X‐ray field through the diffuse‐scattering channel, which is not negligible relative to the coherent diffraction.

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