Evolution of the Internal Structure of Short-Period Cr/V Multilayers with Different Vanadium Layers Thicknesses

Cr/V multilayer mirrors are suitable for applications in the “water window” spectral ranges. To study factors influencing the internal microstructure of Cr/V multilayers, multilayers with different vanadium layers thicknesses varying from 0.6 nm to 4.0 nm, and a fixed thickness (1.3 nm) of chromium layers, were fabricated and characterized with a set of experimental techniques. The average interface width characterizing a cumulative effect of different structure irregularities was demonstrated to exhibit non-monotonous dependence on the V layer thickness and achieve a minimal value of 0.31 nm when the thickness of the V layers was 1.2 nm. The discontinuous growth of very thin V films increased in roughness as the thickness of V layers decreased. The columnar growth of the polycrystalline grains in both materials became more pronounced with increasing thickness, resulting in a continuous increase in the interface width to a maximum of 0.9 nm for a 4 nm thickness of the V layer.

Experimental study of the vibration characteristics of the floating slab track in metro turnout zones

In railway turnout areas, vertical and horizontal structure irregularities, including geometry and stiffness, result in vibration amplification during the passage of trains. These vibrations can then spread to the surrounding environment. A steel spring floating slab track may be used to control such vibrations, especially in metro-type urban railways. An experimental study was conducted to investigate the vibration-mitigating effects of the floating slab track in turnout areas, and the results were compared with the performance of a regular slab track. Four test cases (consisting of six test sections) were selected: a floating slab track in the turnout zone (consisting of a switch rail section and a nose rail section), a floating slab track in the plain line, a slab track in the turnout zone (consisting of a switch rail section and a nose rail section), and a slab track in the plain line. The vibration characteristics of the floating slab track in the plain line and in the turnout were calculated to explain the test results. The test results indicate that when trains pass across the floating slab track in the turnout zone, the vertical vibration response is close to the horizontal response on the switch rail sections. The use of floating slab track can effectively reduce this vertical vibration. However, the vertical vibration response is much larger than the horizontal response on the nose rail sections of the turnout zone. When the floating slab track is used in these turnout zones, the vertical vibration of the rail decreases while the horizontal vibration increases. Compared to sections using the regular slab track in the turnout zone, the vibration of the floating slab track segments in the turnout zone is shown to be exacerbated, although the vibration level at the adjacent tunnel wall is effectively reduced.

Интерференция нейтронных волн при малоугловом рассеянии на ферромагнитных сплавах

The detection conditions and features of direct and scattered neutron wave interference are studied on magnetized Co_67Fe_31V_2 alloy slabs. The angular intensity distributions of neutrons passed through a sample are measured for the opposite polarization directions of the initial neutron beam. The sought-for effect that is induced by the magnetic scattering on crystal structure irregularities in specimens manifest itself by different areas of peaks “without neutron spin flip.” The ratio of these areas depends on the thermal treatment mode, sample thickness and strength of the magnetic field applied to the sample. The peaks “with neutron spin flip” are due to the mechanism of neutron wave passage through magnetononcollinear boundaries. The methods for experimental data acquisition and processing are reported as well.

Detection of Fabric Structure Irregularities Using Air Permeability Measurements

In this paper we demonstrate the possibility of using the close relationship between structure and air permeability of a woven fabric for the detection of the non-uniformity (or defects) in the structure of the fabric. Air permeability of fabrics is a principal property of the structure of a textile material. A very small change in the structure of the fabric at a given location causes a change in the permeability at that location. First we measure the air permeability at defined locations of the fabric. The method allows us to detect areas with an extreme value of permeability – the locations “suspected” of extreme unevenness of fabric's structure. Second, we explore the structure of the fabric in these areas of extreme values of the permeability and attempt to determine the causes of the irregularities in the fabric's structure. To quantify and describe the degree of these irregularities we applied methods of image analysis and statistical processing on acquired data. For our experiment, woven fabrics in the plain weave made from 100% staple yarn polyester were used. Results of our research confirm that significantly greater permeability variations occur in the weft direction of the fabric. Subsequent analysis of the structure of the fabric shows the bimodal nature or the data corresponding to the measurement of width of inter-yarn pore in the place of the maximal value of permeability. The observed higher value of permeability can be attributed to the irregularity of warp yarns at a given location of fabric. Initial permeability measurements enabled us to detect locations of its extreme values. Further close examination of these “suspected” locations of the fabric by a detailed analysis of the structure lead to the determination of the causes of the related irregularities.

Thermal Behavior ofTiO2-xNxNanostructured Powder

Diffusion structural analysis (DSA), based on the measurement of the release of radon previously incorporated into the samples, was used to characterize thermal behavior of N-doped titania powder prepared by heat treatment of anatase in gaseous ammonia at575∘Cand the referenceTiO2powder prepared from the ST-01 anatase titania powder (Ishihara Ltd., Japan). The results of DSA, surface area and porosity measurements by nitrogen adsorption, SEM micrographs, XPS, and XRD are presented and discussed. The results of DSA are in agreement with the results of other methods and indicated the annealing of the subsurface structure irregularities of the samples. Transport properties of the samples were determined from the mobility of radon atoms released on sample heating in air. The decrease of radon permeability in the porous titania powders in the temperature range 850–1000∘Cdue to annealing of the subsurface structure irregularities, that served as radon diffusion paths in the samples, was evaluated from the DSA results.