DEVELOPMENT OF A MODEL FOR THE PRODUCTION OF METAL-POWDER COMPOSITIONS BASED ON CO-CR ALLOYS BY ELECTROEROSIVE DISPERSION

Abstract. The main requirement for powders for additive 3d technologies is the spherical shape of theparticles. Such particles are most compactly packed into a certain volume and ensure the "fluidity" of the powder composition in the supply systems of the material with minimal resistance. The wide use of the EED method for processing metal waste into powders for the purpose of their reuse and application in additive technologies is hampered by the lack in the scientific and technical literature of full-fledged information on the effect of the initial composition, regimes and media on the properties of powders and technologies of practical application. Therefore, in order to develop technologies for the reuse of electroerosive powders and to evaluate the effectiveness of their use, complex theoretical and experimental studies are required. The aim of the work was to develop a model for the production of metal powder compositions on the basis of Co-Cr alloys by electroerosive dispersion. Based on the results of the conducted studies, it has been established that the optimum parameters for the process of obtaining powder materials by the method of electroerosive dispersion of butyl alcohol are: capacitance of discharge capacitors 48 μF, voltage on electrodes 100 V, repetition rate of pulses 120 Hz

Impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field

We report on the observation and experimental studies of impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field. The terahertz electroluminescence is observed in a wide range of doping levels (at noncompensated donor density from 4.5×10[sup 16] to 3.4×10[sup 18] cm[sup −3]). Spectra of terahertz luminescence and photoconductivity are studied by means of Fourier transform spectrometry. Distinctive features of the spectra can be assigned to intracenter electron transitions between excited and ground states of silicon and oxygen donors and to hot electron transitions to the donor states.Peer reviewe

Poloidal inhomogeneity of the particle fluctuation induced fluxes near of the LCFS at lower hybrid heating and improved confinement transition at the FT-2 tokamak

This paper deals with the new spectral and microturbulence experimental data and their analysis, which show, that the radial electric field Er generated at the LH heating (LHH) in the FT-2 is high enough to form the transport barriers. The ETB is formed when LHH is switched off. The radial fluctuation-induced EB drift flux densities near LCFS in SOL are measured at two different poloidal angles. For this purpose two Langmuir probes located at low and high field sides of the torus are used. Registration of the poloidal and radial components of the electric field and density fluctuations at the same time during one discharge permits to measure the poloidal asymmetry of the transport reduction mechanism of the radial and poloidal particle fluxes in the SOL. The absolute E(~) fluctuation levels show dependence on the sign of Er shear. The modification of the microscale turbulence by the poloidal Er x B rotation shear EB at the L - H transition near LCFS is also studied by X-mode fluctuation Reflectometry. The new data were obtained by spatial spectroscopic technique.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Сравнительный анализ кишечной микробиоты при болезни Паркинсона и других неврологических заболеваниях

Currently the role of microbiota in diseases pathogenesis, its therapeutic and diagnostic potential are of the utmost interest for scientists and medical doctors. Parkinson’s disease is neurodegenerative disorder for which microbiota’s dysbiosis was previously shown.The main goal of the study is to compare the colon microbiota composition in case of Parkinson’s disease and other neurological pathologies, including idiopathic familial dystonia, essential tremor, multiple sclerosis, multiple system atrophy in order to determine the intestinal flora landscape specific to Parkinson’s disease.Material and methods. One hundred twenty-six patients, 93 with Parkinson’s disease and 33 with other neurological pathology were examined. For all patients, physical examination and fecal samples collection were performed. Microbiota taxonomic composition was analyzed by sequencing of bacterial 16S rRNA genes followed by bioinformatic and statistical analysis.As a result of the study, significant differences between groups in microbiota composition were found. Gut microbiota of patients with Parkinson’s disease was characterized by increase of Desulfovibrio piger, Lactobacillus mucosae, Yokenella regensburgei, Alistipes indistinctus, Oscillospira capillosus, Clostridium bolteae, Soleaferrea massiliensis, Butyricimonas virosa, Dorea massiliensis, Victivallis vadensis abundances. Patients with other neurological diseases had increased levels of bacteria belonging to Blautia, Intestinibacter, Coprococcus genera and Anoxystipes fissicatena, Fusobacterium periodonticum, Gemmiger formicilis, Papillibacter cinnamivorans, Roseburia faecis, Lachnoclostridium indolis, Clostridium populeti, Clostridium tertium, Roseburia intestinalis, Eubacterium desmolans, Eubacterium cylindroides, Clostridium clariflavum, Eubacterium eligens, Coprococcus eutactus, Intestinibacter bartlettii species in their gut microbiota.Consequently, gut microbiota in case of Parkinson’s disease was different from the microbiota of patients with other neurological diseases, including neuroinflammatory and neurodegenerative disorders, in terms of taxonomic diversity and composition. В настоящее время большой интерес представляет роль микробиоты в патогенезе различных болезней, а также ее диагностический и терапевтический потенциал. Болезнь Паркинсона – нейродегенеративное заболевание, для которого было показано изменение состава кишечной микробиоты в сравнении со здоровым контролем.Цель данного исследования – сравнительная характеристика кишечной микробиоты лиц с болезнью Паркинсона и другими неврологическими заболеваниями, включая идиопатическую семейную дистонию, эссенциальный тремор, рассеянный склероз, множественную системную атрофию для определения микробиотического ландшафта, характерного именно для болезни Паркинсона.Материал и методы. В исследование были включены 93 пациента с диагнозом болезни Паркинсона и 33 пациента с иными неврологическими заболеваниями. Для каждого пациента проведено физикальное обследование и собраны образцы фекалий. Определение состава микробиоты проводилась секвенированием бактериальных генов 16S рРНК с последующим биоинформатическим и статистическим анализом.Результаты. При сравнительном анализе состава микробиоты были найдены значимые различия. Микробиота кишечника лиц с болезнью Паркинсона характеризовалась увеличением содержания бактерий видов Desulfovibrio piger, Lactobacillus mucosae, Yokenella regensburgei, Alistipes indistinctus, Oscillospira capillosus, Clostridium bolteae, Soleaferrea massiliensis, Butyricimonas virosa, Dorea massiliensis, Victivallis vadensis. У лиц с другими неврологическими заболеваниями преобладали бактерии родов Blautia, Intestinibacter, Coprococcus и видов Anoxystipes fissicatena, Fusobacterium periodonticum, Gemmiger formicilis, Papillibacter cinnamivorans, Roseburia faecis, Lachnoclostridium indolis, Clostridium populeti, Clostridium tertium, Roseburia intestinalis, Eubacterium desmolans, Eubacterium cylindroides, Clostridium clariflavum, Eubacterium eligens, Coprococcus eutactus, Intestinibacter bartlettii.Выводы. Микробиота кишечника при болезни Паркинсона отличается по таксономическому разнообразию и бактериальному составу от микробиоты пациентов с другими неврологическими заболеваниями, в том числе нейровоспалительными и нейродегенеративными.