Neuronet data processing algorithms in laser interferometer circuit at detecting object’s low oscillations and vibrations

A neuronet algorithm of interferometer data processing was developed for detection of microoscillations of the object. The algorithm parameters analysis has been carried out and sensitivity of the technique has been evaluated using experiment and simulation data. The article is published in the original.     

Expansion shock waves in numerical solutions of gasdynamic problems

The properties of diverse difference schemes of gas dynamics (nonconservative, conservative, and completely conservative) were studied with reference to the example of the classical problem of a piston. It is shown that in the case in which the piston is pulled out of a gas with the formation of an expansion wave, the application of schemes without a sufficient stability margin can lead to the appearance of discontinuities in the form of expansion shock waves. The explanation of this effect and possible ways for eliminating it are proposed     

Polychlorinated phenols in total diet

A method has been developed for the isolation, separation and determination of chlorinated phenols in total diet. The isolation takes place following acid hydrolysis of the conjugates and is performed by simultaneous extraction and distillation with water vapour and toluene. The isolated chlorophenols are removed by clean-up on a Florisil column using a mixture of 15% dichloromethane in toluene for elution. The separation and determination is carried out by capillary gas chromatography with electron capture detection. The recovery of the method ranged between 70.1±5 and 96.8±4.9% for the individual chlorophenols. The determination limits were 0.5 to 1.0 g·kg^–1. The method was applied in a study aimed at estimating the chlorophenol burden in two population groups (children up to the age of 6 years and students up to the age of 18 years). In two succesive years, 80 total diet samples were analysed. Average contents of the individual chlorophenols were from 0.7 to 33.5 g·kg^–1 and were higher for the dichlorophenol isomers. The calculated average daily intake ranged from 0.04 to 1.69 g·kg^–1 body weight for the individual phenols.

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Polychlorierte Phenole im Gesamtverzehr

Zusammenfassung Das hier beschriebene Verfahren dient zur Isolierung, Trennung und Bestimmung von chlorierten Phenolen im Gesamtverzehr. Dieser wurde sauer hydrolysiert, die Phenole wurden durch eine simultane Wasserdampfdestillation und ein Extraktionsverfahren mit Toluol isoliert. Beim anschließenden Derivatisierungsverfahren mit Pentafluorobenzylbromid entstanden auch Störungssubstanzen, sie wurden mittels Säulenchromatographie an Florisil abgetrennt. Die chromatographische Trennung und Bestimmung erfolgte unter Anwendung der Kapillargaschromatographie mit ECD. Die Wiederfindungsrate variierte zwischen 70.1±5 und 96.8±4.9% bei Nachweisgrenzen von 0.5 bis 1.0 g·kg^–1. Das Verfahren wurde zur Ermittlung der Exposition bei Kindern bis zu 6 Jahren und Jungen bis zu 18 Jahren verwendet. Im Laufe von 2 Jahren wurden 80 Proben des Gesamtverzehrs aus Kindereinrichtungen analysiert. Der Durchschnittsinhalt schwankte von 0.7 bis 33.5 g·kg^–1 mit Überwiegen von Dichlorophenolen. Die aus den bekannten Inhalten ermittelte Tagesaufnahme variiert zwischen 0.04 und 1.69 g·kg^–1 Körpermasse und Tag.

     

Echelles: scalar, electromagnetic, and real-groove properties

For lack of alternatives, echelle-grating diffraction behavior has in the past been modeled on scalar theory, despite observations that indicate significant deviations. To resolve this difficulty a detailed experimental, theoretical, and numerical study is performed for several echelles that work at low (18-13), medium (35-55), high (84-140), and very-high (to 660) diffraction orders. Noticeable deviations from the scalar model were detected both experimentally and numerically, on the basis of electromagnetic theory: (1) the shift of the observed blaze position was shown to decrease with the wavelength-to-period ratio, and it tends to zero more rapidly than the decrease of the maximum width, so that the TE- and TM-plane responses tend to merge into each other; (2) cut-off effects (Rayleigh anomalies) were found to play a significant role for high groove angles, where passing-off orders are close to the blaze order. A possibility for evaluation of the blaze angle from angular, rather than from spectral, measure nts is discussed.Several reasons for the differences between real and ideal echelles (material-index deviations, profile deformations, and groove-angle errors) are analyzed, and their effects on the performance of echelles is studied.     

Light diffraction from rough gratings

Two holographic diffraction gratings with very similar parameters, designed for maximum performance inTM polarization, are investigated, their diffraction efficiency measured, an electron microscopic picture of their surface observed, and numerical simulation of light diffraction done with the surface roughness taken into account. It is demonstrated numerically that a small-scale roughness imposed on the grating surface could increase significantly both scattering and absorption from the surface, this influence being greater in the TM case. A very good coincidence between the numerical and experimental data is obtained in TE polarization, whereas in TM polarization only a qualitative agreement exists.     

Theoretical and numerical investigations of the polarization properties of a lidar signal scattered by a set of oriented ice plates

The relationships for the backscattering cross sections are derived within the scope of the physical-optics method for the case in which polarized optical radiation interacts with an oriented semitransparent circular plate. Theoretical investigation of the depolarization relation is carried out for the polarization signal backscattered from a set of oriented circular plates. An algorithm is suggested for the calculation of the orientation angles of the plates in the scattering volume.     

Study of DNA Origami Dimerization and Dimer Dissociation Dynamics and of the Factors that Limit Dimerization

Organizing DNA origami building blocks into higher order structures is essential for fabrication of large structurally and functionally diverse devices and molecular machines. Unfortunately, the yields of origami building block attachment reactions are typically not sufficient to allow programed assembly of DNA devices made from more than a few origami building blocks. To investigate possible reasons for these low yields, a detailed single‐molecule fluorescence study of the dynamics of rectangular origami dimerization and origami dimer dissociation reactions is conducted. Reactions kinetics and yields are investigated at different origami and ion concentrations, for different ion types, for different lengths of bridging strands, and for the “sticky end” and “weaving welding” attachment techniques. Dimerization yields are never higher than 86%, which is typical for such systems. Analysis of the dynamic data shows that the low yield cannot be explained by thermodynamic instability or structural imperfections of the origami constructs. Atomic force microscopy and gel electrophoresis evidence reveal self‐dimerization of the origami monomers, likely via blunt‐end interactions made possible by the presence of bridging strands. It is suggested that this mechanism is the major factor that inhibits correct dimerization and means to overcome it are discussed.     

3D-Druck für Hochvakuumanwendungen

To mark our anniversary, we are presenting articles that have been particularly appreciated by readers of our online edition once again in print. Here: 3D-Printing for High Vacuum Applications 3D printing technology has made the leap from a home-based private practice to industrial manufacturing. Due to the increasing reliability of printers and increasing material diversity, especially in the metal sector, double-digit percentage growth rates are possible in the coming years. This thesis deals with the manufacture of parts made by 3D printing for high vacuum application. Different components are printed and examined for their vacuum compatibility. As shown furthermore, conventionally made standard components can be vacuum sealed to printed parts, which enables cost-effective production of more complex components, such as e.g. a vacuum chamber allows. In addition, functional components can already be realized in the manufacturing process. The integration of a system of flow channels directly into the wall of a chamber is just one example. Thus, such a chamber can be heated during evacuation and effectively cool in later operation.     

Diffraction efficiency of echelles working in extremely high orders

Aproposal to use a high-angle echelle in the vacuum UV in the 350th order triggered a theoretical study to determine if there were unusual obstacles to success. No serious obstacles were found except for efficiency limitations.