Structure evolution of tungsten coatings exposed to plasma flows under ITER ELM relevant conditions

Structure, substructure and stress parameters both on the surface and distributed by depth in the tungsten/steel coatings exposed to high energy hydrogen plasma fluxes were studied by X-ray diffraction methods. The hydrogen plasma exposure results in the following recrystallization processes in the thin surface layer of the coating: appearing the texture axis [100] normal to the surface; increasing the coherence length from 60 nm in the initial state to 80 nm after the plasma exposure; completely annealed micro-strains; and dislocation density lowered twice in the exposed surface layer - all these facts confirm the thermal character of the hydrogen plasma influence. No structure variations were observed already at the depth near 1 m of the coating.Методами рентгеновской дифракции изучено изменение параметров структуры, субструктуры и напряжённого состояния на поверхности и по глубине покрытий вольфрам/сталь после облучения потоком водородной плазмы. Облучение плазмой приводит к рекристаллизационным процессам в тонком поверхностном слое покрытия: появлению текстуры [100] по нормали к поверхности, увеличению областей когерентного рассеяния от 60 нм в исходном состоянии до 80 нм после облучения, полному отжигу микронапряжений, а также уменьшению в два раза плотности дислокаций. Это подтверждает термический характер воздействия водородной плазмы. Уже на глубине около 1 мкм в покрытии никаких структурных изменений не выявлено.Методами рентгенівської дифракції вивчено змінення параметрів структури, субструктури та напруженого стану на поверхні та по глибині покриттів вольфрам/сталь після опромінення потоком водневої плазми. Опромінення плазмою призводить до рекристалізаційних процесів у тонкому поверхневому шарі покриття: виникненню текстури [100] по нормалі до поверхні, збільшенню областей когерентного розсіювання від 60 нм у початковому стані до 80 нм після опромінення, повному відпалу мікронапружень, а також зменшенню у двічі густини дислокацій. Це підтверджує термічний характер впливу водневої плазми. Вже на глибині біля 1 мкм у покритті ніяких структурних змін не виявлено

Contemporary integrative taxonomy for sexually deprived protists: A case study of Trachelomonas (Euglenaceae) from western Ukraine

As many other protist groups, euglenophytes are prone to false identification based solely on morphology because of a limited amount of morphological features and cryptic speciation. One of the supposedly completely asexual groups within the freshwater phototrophic representatives of euglenophytes is Trachelomonas , capable of forming an inorganic shell around its cell (i.e., the lorica). The International Code of Nomenclature for algae, fungi, and plants regulates the taxonomy not only of flowering plants, but explicitly also of phototrophic protists, and provides powerful tools to resolve various taxonomic challenges. To exemplify some of the problems and potential solutions, a number of Trachelomonas strains were collected from the muddy, lake‐rich region of Dobrostany and cultivated under stable laboratory conditions. Being a type locality of 58 unclarified Trachelomonas names, this region in western Ukraine is of great taxonomic importance. Based on light and electron microscopy, and on RAxML and MrBayes phylogenetics using multiple loci and a representative taxon sample, a detailed description of investigated strains and their systematic placement is provided. Morphologically, the strains differed slightly but consistently in minute characters such as size, lorica shape and ornamentation. The presently most comprehensive molecular tree of the Euglenaceae indicated to the existence of at least five different species present in the newly investigated samples, although they were collected from localities in very close vicinity to each other and at the same date. Based on morphological comparisons with type illustrations of species validly described 100 or more years ago, biological material was used to epitypify three names of Trachelomonas , eternally linking morphology with reliable genetic information. This taxonomic application is one of the powerful methods to clarify ambiguous scientific names, which has particular importance in character‐poor protists such as the euglenophytes

HISTIDINE BIOTRANSFORMATION MEDIATED BY L-HISTIDINE-AMMONIA-LYASE

Kinetics of the metabolism of the heterocyclic amino acid histidine exposed to the L-histidine ammonia-lyase enzyme has been investigated and the technology of extraction of histidine biotransformation products (urocanic acid and ammonia) from casein hydrolyzates enabling the subsequent use of these hydrolyzates as a milk protein concentrate for the production of specialized dietary products for the nutrition of histidinemia patients has been developed

Synthesis of amphiphilic block-gradient copolymers of styrene and acrylic acid by nitroxide mediated polymerization

cited By 1International audienceWe present an overview on synthesis of amphiphilic ionic block-gradient copolymers of styrene and acrylic acid by means of one step direct Nitroxide Mediated Polymerization (NMP) and their characterization. The copolymers comprise a block of poly(acrylic acid) and one or two terminal blocks that include co-monomer units of styrene and acrylic acid in variable proportion. Using 1H NMR the gradient sequence of the poly(acrylic acid-co-styrene) copolymer block has been confirmed. In contrast to diblock copolymers of styrene and acrylic acid, that are known to form in aqueous environment “frozen” aggregates with glassy poly(styrene) core, the novel block gradient copolymers exhibit stimuli-responsive aggregation behavior, as was demonstrated by subsequent studies. This feature makes them very promising for design of a large variety of smart functional materials. © Pleiades Publishing, Ltd., 2015

The well-defined bootstrap effect in the macroinitiator-mediated pseudoliving radical copolymerization of styrene and acrylic acid

cited By 8International audienceThe bootstrap effect is observed in the pseudoliving radical copolymerization of styrene and acrylic acid mediated by a macroinitiator: the adduct of poly(acrylic acid) with a nitroxide radical. In this case, the macroinitiator serves as a peculiar "microreactor" with an increased local concentration of acrylic acid; as a result, the apparent activity of acrylic acid is higher than that in copolymerization mediated by low-molecular-mass initiators. © 2013 Pleiades Publishing, Ltd

New efficient method for activation of dormant chains in pseudoliving radical polymerization

cited By 4International audienceWith the use of the competitive inhibition method and ESR spectroscopy, it is shown that, in pseudoliving radical polymerization, the rate constant of decomposition of PS and poly(acrylic acid) adducts with nitroxide radicals significantly increases as the polarity of a medium increases. This phenomenon opens a new approach to the activation of chains in nitroxide-mediated polymerization. © 2011 Pleiades Publishing, Ltd

СОЗДАНИЕ ВСПОМОГАТЕЛЬНОГО ЭЛЕКТРОННОГО РЕСУРСА КАК ЧАСТИ ПРОЦЕССА ОБУЧЕНИЯ ИНОСТРАННОМУ ЯЗЫКУ

The article analyses a number of problems that lecturers and students are facing during the process of study. The lack of timetable hours, oversized groups and students of different language levels within one group slow down the process of formation, development and improvement of language skills. The authors stress the necessity to use the elements of electronic learning to organize proper teaching process and highlight the advantages of the electronic course, which gives more opportunities for students to practice their language skills

Effect of temperature on self-assembly of amphiphilic block-gradient copolymers of styrene and acrylic acid

cited By 1International audienceThe effect of temperature on self-assembly of a novel type of amphiphilic ionic copolymers comprising a hydrophilic poly(acrylic acid) PAA block and an amphiphilic poly(acrylic acid)-grad-poly(styrene) PAA-grad-PS copolymer block has been studied by Small Angle Neutron and Dynamic Light Scattering (SANS, DLS). The polymers have been synthesized using direct Nitroxide-Mediated Polymerization (NMP) as described elsewhere and proved to be capable of formation of the equilibrium (dynamic) micelles responsive to variations in pH and ionic strength of the solution. We have demonstrated that an increase in temperature from 20 to 80°C has almost no influence if the assembly occurs at pH∼6 in a wide range of salt concentration. Under these conditions stable micelle aggregates are formed. At pH∼6.9 virtually no aggregation occurs at any temperature in salt-free solution, whereas at 1M salt concentration we observed an appearance of the correlation peak in the scattering curves and an increase in hydrodynamic radius in dilute solutions evidencing self-association of polymer chains. The magnitude of the correlation peak increases upon an increase in temperature. This behaviour may be attributed to the combined effect of temperature on the ionization constant and on the strength of hydrophobic interactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

A new approach towards the synthesis of pyrrolo[2,1-a]isoquinolines

Reaction of 5-bromo-2-methyl-8-nitro-1,2,3,4-tetrahydroisoquinoline with activated alkynes affords stable tetrahydropyrrolo[2,1-a]isoquinolin-4-ium ylides. Further reactions of ylide 2 gives access to substituted dihydropyrrolo[2,1-a]isoquinolines in good yields. © 2009 Elsevier Ltd. All rights reserved