The Passions of Chichikov: Gogol's Soteriological Scheme

Некоторые попытки в постсоветской критике вчитать Гоголя-христианина в Гоголя-автора характеризуются тенденциозной односторонностью. Духовно-литературные каноны вписываются в христианскую ортодоксальность позднего Гоголя не в меньшей мере, чем в гротеск и абсурд первой части "Мертвых душ". Важную роль в этом отношении играют деконструированная христология в характеризации Чичикова и пародийная теология спасения в сюжете хождений героя. Эти элементы указывают на определенную литературизацию библейских евангелий, которую впоследствии не удалось автору вытеснить своим окончательным стремлением к богословско-ортодоксальной развязке в "Мертвых душах"

Chemical, thermal and laser treatment in recycling of photovoltain solar cells and modules from crystalline silicon

W ostatnich latach systemy fotowoltaiczne stają się bardzo popularne na całym świecie jako korzystne dla środowiska rozwiązanie problemów energetycznych. Zagadnienie zagospodarowania zużytych elementów systemów fotowoltaicznych, których ilość w przyszłości może być znaczna, nie zostało do tej pory opracowane. Konieczne jest znalezienie optymalnej metody recyklingu i ponownego wykorzystania wycofanych z użycia elementów składowych systemów PV. W artykule przedstawiono wybrane sposoby prowadzenia recyklingu zużytych lub uszkodzonych modułów i ogniw fotowoltaicznych oraz praktyczne wyniki prac eksperymentalnych z wykorzystaniem metod: chemicznych, termicznych oraz techniki laserowej. Opisano wady i zalety stosowanych technik, pomocne przy optymalizowaniu metody recyklingu dla zastosowań komercyjnych. Proces recyklingu modułów PV wymaga zastosowania dwóch zasadniczych etapów: separacji ogniw PV i oczyszczania ich powierzchni. W procesie separacji ogniwa wchodzące w skład modułu PV zostają rozdzielone w efekcie zastosowania procesów termicznych lub chemicznych. W następnej fazie ogniwa poddaje się procesowi, w którym usuwa się niepożądane warstwy: antyrefleksyjną, metalizację oraz złącze n-p, aby uzyskać podłoże krzemowe, nadające się do powtórnego zastosowania. Etap oczyszczania powierzchni krzemowych ogniw PV prowadzono z zastosowaniem obróbki chemicznej oraz techniki laserowej.In recent years, photovoltaic power generation systems have been gaining unprecedented attention as an environmentally beneficial method to solve the energy problem. From the economic point view the pure silicon, which can be recapture from the used cells, is the most important material due to its cost and shortage. In the article selected methods of used or damaged module and cells recycling and experimental results are presented. Advantages and disadvantages of these techniques are described, what could be helpful during the optimization of the method. The recycling process of PV module consists of two main steps: separation of cells and its refining. During the first step cells are separated due to the thermal or chemical methods usage. Next, the separated cells are refining. During this process useless layers are removed: antireflection, metallization and p-n junction layer, for silicon base - ready to the next use - gaining. This refining step was realized with the use of chemical and laser treatment as well

Effect of laser drilling on surface and material properties of AlN ceramics

For the laser drilling of aluminum nitride (AlN) ceramic the influence of the laser parameters and material properties on the drilling rate, quality of the holes and the effects related to plasma formation are investigated. The ablation is performed by pulsed irradiation of Nd:YAG laser at wavelengths of 1064, 532 and 355 nm, at pulse duration of 6 ns (FWHM) in air. The SEM scans of the processed surface reveal regular, cylindrically shaped holes of diameter of about 100 μm obtained under conditions of constant fluence at all wavelengths applied. Holes are surrounded by circular zones which are colored different than the non-processed surface, and of a much larger diameter. Comparison of the original material composition with that of the processed one made by EDX shows a decrease of the N concentration in the affected area. The zones are identified as heat-affected due to the high thermal conductivity of the ceramic material and change of the photon distribution due to multiple reflections into the material. In the LIBS spectra recorded in order to obtain the composition of the ablated material the presence of ions and neutrals depends on the laser intensity applied. At intensity values close to the ablation threshold the ejected material consists mainly of neutrals and doubling the intensity results in appearance of single-ionized Al species. The ionized species dominate over neutrals under conditions of higher drilling rate (15 GW/cm2 at 532 nm). Their existence in the plasma plume together with clusters is confirmed by the TOF-MS spectra. It also corresponds to the characteristic spatial structure of the plume. The investigation of the decomposition reactions of AlN in dependence on the applied laser intensity is based on numerical solving of the three dimensional heat-transfer equation. A solution consistent with the experimental observation indicates that at threshold the ceramic decomposes into gaseous nitrogen and solid Al particulates, while at higher fluences the Al vaporizes and influences the drilling quality

Analysis of surface and material modifications caused by laser drilling of AlN ceramics

For the laser drilling of aluminum nitride ceramic the processing results and the effects related to pulsed irradiation were investigated. Images of the drilled surface revealed regular, cylindrically shaped holes of about 100 μm in diameter independently of the laser wavelength (1064/532/355 or 266 nm). The holes were surrounded by circular heat-affected zones of larger diameter. A comparison of the elemental compositions of the original material and the processed one indicated a decrease of the nitrogen concentration in the affected area. The spectral analysis of the ablated material composition revealed the presence of ions and neutrals in dependence on the laser intensity applied. It was found that at intensity values close to the ablation threshold the ejected material consisted mainly of neutrals, while doubling of the intensity resulted in appearance of single-ionized Al species, which were also observed together with Al clusters in the mass spectra of the UV-excited plasma. Their prevailing content was revealed for drilling at higher intensities around 15 GW/cm2 at 532 nm. Results of model calculations indicated, in agreement with the experiment, that at the threshold the ceramic decomposes into gaseous nitrogen and solid Al particulates, while at a higher fluence the material particles vaporize and influence the quality of drilling. © 2007 Elsevier B.V. All rights reserved

Controlling crystallites orientation and facet exposure for enhanced electrochemical properties of polycrystalline MoO3 films

Abstract This study focuses on the development and optimization of MoO3 films on commercially available FTO substrates using the pulsed laser deposition (PLD) technique. By carefully selecting deposition conditions and implementing post-treatment procedures, precise control over crystallite orientation relative to the substrate is achieved. Deposition at 450 °C in O2 atmosphere results in random crystallite arrangement, while introducing argon instead of oxygen to the PLD chamber during the initial stage of sputtering exposes the (102) and (011) facets. On the other hand, room temperature deposition leads to the formation of amorphous film, but after appropriate post-annealing treatment, the (00k) facets were exposed. The deposited films are studied using SEM and XRD techniques. Moreover, electrochemical properties of FTO/MoO3 electrodes immersed in 1 M AlCl3 aqueous solution are evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrate that different electrochemical processes are promoted based on the orientation of crystallites. When the (102) and (011) facets are exposed, the Al3+ ions intercalation induced by polarization is facilitated, while the (00k) planes exposure leads to the diminished hydrogen evolution reaction overpotential

The new method of ZnIn2S4 synthesis on the titania nanotubes substrate with enhanced stability and photoelectrochemical performance

Abstract In this work, ZnIn2S4 layers were obtained on fluorine doped tin oxide (FTO) glass and TiO2 nanotubes (TiO2NT) using a hydrothermal process as photoanodes for photoelectrochemical (PEC) water splitting. Then, samples were annealed and the effect of the annealing temperature was investigated. Optimization of the deposition process and annealing of ZnIn2S4 layers made it possible to obtain an FTO-based material generating a photocurrent of 1.2 mA cm−2 at 1.62 V vs. RHE in a neutral medium. In contrast, the highest photocurrent in the neutral electrolyte obtained for the TiO2NT-based photoanode reached 0.5 mA cm−2 at 1.62 V vs. RHE. In addition, the use of a strongly acidic electrolyte allowed the generated photocurrent by the TiO2NT-based photoanode to increase to 3.02 mA cm−2 at 0.31 V vs. RHE. Despite a weaker photoresponse in neutral electrolyte than the optimized FTO-based photoanode, the use of TiO2NT as a substrate allowed for a significant increase in the photoanode's operating time. After 2 h of illumination, the photocurrent response of the TiO2NT-based photoanode was 0.21 mA cm−2, which was 42% of the initial value. In contrast, the FTO-based photoanode after the same time generated a photocurrent of 0.02 mA cm−2 which was only 1% of the initial value. The results indicated that the use of TiO2 nanotubes as a substrate for ZnIn2S4 deposition increases the photoanode's long-term stability in photoelectrochemical water splitting. The proposed charge transfer mechanism suggested that the heterojunction between ZnIn2S4 and TiO2 played an important role in improving the stability of the material by supporting charge separation

Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy

Skin lesions are commonly treated using laser heating. However, the introduction of new devices into clinical practice requires evaluation of their performance. This study presents the application of optical phantoms for assessment of a newly developed 975-nm pulsed diode laser system for dermatological purposes. Such phantoms closely mimic the absorption and scattering of real human skin (although not precisely in relation to thermal conductivity and capacitance); thus, they can be used as substitutes for human skin for approximate evaluation of laser heating efficiency in an almost real environment. Thermographic imaging was applied to measure the spatial and temporal temperature distributions on the surface of laser-irradiated phantoms. The study yielded results of heating with regard to phantom thickness and absorption, as well as laser settings. The methodology developed can be used in practice for preclinical evaluations of laser treatment for dermatology