Analysing detection bands of two-spectral reflection method to identify forest species composition

The optical reflection method is considered for detection of the forest areas where coniferous or broadleaved trees are dominant. Statistical modelling of correct detection and false alarm probabilities for identifying dominant (coniferous or broadleaved) tree species by the two-spectral reflection method has been conducted. It has been shown that monitoring enables us to identify dominant (coniferous or broadleaved) tree species with correct detection probability close to 1 and false alarms probability ~ second decimal places for the temperate climate zone at the wavelengths of 532 and 1540 nm or 532 and 1480 nm. As to the subtropical climate zone, due to a great variety of reflection spectra of vegetation, a selection of the spectral detection bands for reliable identification of dominant coniferous or broadleaved tree species is possible only for specific forestlands where the number of evergreen broadleaved and coniferous tree species is relatively small.

Metrological studies of the characteristics of multilayer surface coatings using synchrotron radiation

The investigations of multilayer surface nanostructures characteristics was performed with synchrotron radiation sources, characterized by an intensive, calculated continuum. It plays an important role in nanoelectronics metrological base. The main research were carried out at electron storage rings «Siberia-1» (Kurchatov Institute) and MLS (PTB, Berlin) with low electron energy, in a wide wavelength range, including visible range, AUV, VU, EUV and to exclude the X-ray radiation influence. The methods of the radiometers, photodiodes, filters and multilayer mirrors characteristics measurements are based on the synchrotron radiation absolute spectral characteristics and accelerated electrons number variation. The metrological investigations with synchrotron radiation was concentrated on: – absolute spectral responsivety of silicon photodiodes with multilayer filters for integral radiometers applications; – spectral transmittances of surface layers of photodiodes in the extreme ultraviolet region; – spectral reflectance coefficient of superlattice. The characteristics of photodiodes and filters on a synchrotron radiation source are measured using a monochromator and a reference detector. The use of a synchrotron radiation channel makes it possible to study the spectral transmittance of thin films and multilayer structures formed in the in situ mode. To form multilayer nanostructures directly on the receiving surface of photodetectors, an ion-plasma sputtering module is used. The optical scheme of the channel provides for the possibility of using monochromators of grazing incidence for the range of photon energies from 25 to 100 ev and normal incidence for the range of photon energies from 4 to 25 ev. At a photon energy of 40 ev, the absolute spectral sensitivity was 70 ma / W for a photodiode with a surface multilayer filter applied. To develop an experimental technique for measuring the spectral reflection coefficient of multilayer mirrors, and to create standard samples, the Mo/Si system was studied. Computer modeling of multi-layer coatings allows us to calculate the optical characteristics of superlattices in the extreme ultraviolet region. The obtained results of measurements of the spectral reflection coefficient of a multilayer coating in the photon energy range of 65–100 ev indicate a resonance reflection character with a max-imum at an energy of 83.5 ev and an energy width at a half-height of about 6.5 ev. The working wave-length of the reflecting mirror corresponds to the calculated one, which confirms the effectiveness of the adopted model.

Изготовление и исследование зеркал с широкой полосой пропускания для синхротронных применений

The work is devoted to the development, fabrication and analysis of broadband W / Si multilayer mirrors for a broadband monochromator, calculated for the spectral range of 7–10 keV. The possibility of using the stacking approach to obtain multilayer mirrors with a reflection coefficient of about 30% and a spectral bandwidth ΔE / E of about 20% is shown. The results of measurements of the angular and spectral reflection curves of the mirror obtained on a laboratory diffractometer and on a synchrotron in Novosibirsk are presented.

The child refugee in Calais: from invisibility to the ‘suspect figure’

This paper examines child refugees in the context of Calais in France, contextualizing them against the politics of the ‘Jungle’ (a makeshift camp) in policy and media discourses in the UK by delineating three distinct phases in the discursive production of these sites in the enactment of this ambiguous entity. These three phases trace the spatio-temporal emergence of the child refugee in the camps to their arrival in the UK. These camps, as transient and symbolic formations inhabited by the ‘dispossessed’ of forced global migration, provide a context in which the figure of the child is enacted from its incidental appearance to its visible manifestation to its final configuration as the ‘suspect figure’ in the UK. Through Derridean ‘hauntology’ of absent presence, the child refugee captures the conflicted morality of the West. As a disenfranchised entity, the child, forged through the turbulence of the Jungle, can be collapsed through the primal and deprived of his or her status as a child (and, in tandem, protection from harm) in public discourses. The child positioned as a ‘suspect figure’ becomes a spectral reflection of the beleaguered West, wrestling with the ideational image of the child and its recurrence as a threat to its moral reserve.