Anti-corrosion ceramic coatings on the surface of Nd-Fe-B repelling magnets

The results of vacuum-arc deposition of thin ZrO₂coatings to protect the surface of Nd-Fe-B permanent magnets used as repelling devices in orthodontics are presented. The structure, phase composition and mechanical properties of zirconium dioxide films have been investigated by means of SEM, XRD, EDX, XRF and nanoindentation method. It was revealed the formation of polycrystalline ZrO₂ films of monoclinic modification with average grain size 25 nm. The influence of the ZrO₂ coating in terms of its barrier properties for corrosion in quasi-physiological 0.9 NaCl solution has been studied. Electrochemical measurements indicated good barrier properties of the coating on specimens in the physiological solution environment

Synthesis and characterisation of nanocrystalline ZrN PVD coatings on AISI 430 stainless steel

The nanocrystalline films of zirconium nitride have been synthesized using ion-plasma vacuum-arc deposition technique in combination with high-frequency discharge (RF) on AISI 430 stainless steel at 150oC. Structure examinations X-ray fluorescent analysis (XRF), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) with microanalysis (EDS), and transmission electron microscopy (TEM), nanoidentation method – were performed to study phase and chemical composition, surface morphology, microstructure and nanohardness of coatings. The developed technology provided low-temperature coatings synthesis, minimized discharge breakdown decreasing formation of macroparticles (MPs) and allowed to deposit ZrN coatings with hardness variation 26.6…31.5 GPa. It was revealed that ZrN single-phase coatings of cubic modification with finecrystalline grains of 20 nm in size were formed

Peritektični čelici: značajke strukture, tehnologije legiranja i primjene

The article presents analysis of phase transformation characteristics, primary structure formation, alloying technology and usage of steels, which undergo a peritectic transformation during their solidification.U članku se predočuje analiza značajki fazne transformacije, nastanka primarne strukture, tehnologije legiranja i primjene čelika podvrgnutih peritektičkoj transformaciji pri skrućivanju

Plant sulfolipid. II. Mutant study and phosphate deficiency

Study with SQDG-deficient mutants showed that formation of the sulfonic acid precursor, UDP-sulfoquinovose, in higher plants is considered to be catalyzed by the orthologous plant proteins SQD1. The second required plant enzyme, SQD2, is highly similar to glycosyltransferases and it is proposed that this protein represents sulfolipid synthase. The results of recent works have shown that for the stable activity PS II needs the presence of SQDG and that it participates in PS II recovering through some mechanism dependent on light. Under phosphate-limiting conditions a decrease in the content of one acidic lipid (PG) was accompanied by an increase in the content of the other acidic lipid (SQDG), which resulted in the maintenance of a certain level of total acidic lipids of chloroplast membranes

Some aspects of periodontitis pathogenesis in children.

Inflammatory processes in the tissues surrounding tooth root are frequent enough and develop as the direct complication of caries. As acute periodontitis is manifested with grinding toothache and violation of ph­y­sio­logical act of chewing, symptoms of general intoxication, the continuous sluggish chronic periodontitis is harmful and dangerous to the organism as well. It forms the state of chronic оdontogenetic intoxication and chroneosepsis with wrong functioning of some internal organs and body systems. The like complications can cause significant disturbance to the function of kidneys, liver, heart, joints and their treatment without ablating focus of inflammation is often in- effective; this must be taken into account by doctors-interns. However, scanning of the oral cavity by conservative means has its difficulties mostly because of ignoring pathogenesis of such inflammation. That is why activity of ferments of blood dehydrogenases from the periapical tissues of the teeth affected with the chronic periodontitis was studied. The level of succinate dehydrogenase and alpha-glycerophosphate degydrogenase of lymphocytes of 110 schoolchildren aged 13-17 years old was studied. The main group of examined individuals included those of infected with tuber­culousis – 50 individuals, and the control group (60 individuals) – clinically healthy ones without tuberculousis desease. All schoolchildren had 1 or 2 teeth affected with chronic periodontitis of the apical localization. The re­searchers found that a significant inhibition of activity of succinate dehydrogenase and alpha-glycerophosphate degydrogenase ferments occurs in the inflammatory periodontal tissues, which indicates to local immunity decline, and as a consequence, pathogenic bacteria activation. In people infected with tuberculousis these violations were  more developed. Such features of periodontitis pathogenesis must be taken into account when providing a combined treatment

Метилювання положення 8 піридинової частини молекули N-(бензил)-2-гідрокси-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксамідів як спроба посилення їх аналгетичних властивостей

The chemical modification of the pyridine moiety of the molecule – displacement of the methyl group in position 8 of pyrido[1,2-a]pyrimidine nucleus has been considered as one of the possible versions to optimize the biological properties of N-(benzyl)-2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides. The synthesis of the research targets was carried out by the reaction of the corresponding benzylamines and ethyl 2-hydroxy-8-methyl-4-oxo-4H-pyrido[1,2-a] pyrimidine-3-carboxylate, in its turn obtained by condensation of 2-amino-4-methylpyridine (i.e. the product with the methyl group in the intentionally required position) and triethyl methanetricarboxylate. The structure of the compounds obtained has been confirmed by the data of elemental analysis and NMR 1H spectroscopy, and in the case of optically active 1-phenylethylamides additionally by polarimetry. The study of the analgesic properties of all N-(benzyl)-2-hydroxy-8-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxamides was performed on the standard experimental “acetic acid writhing” model. At the same time, it has been found that our modification is accompanied with the increased biological activity of exclusively para-substituted derivatives. For profound research 4-fluorobenzylamide exceeding Piroxicam and Nabumetone by the level of the specific effect has been recommended as a potential new analgesic.В качестве одного из возможных вариантов оптимизации биологических свойств N-(бензил)-2-гидрокси-4-оксо-4Н-пиридо[1,2-a]пиримидин-3-карбоксамидов рассмотрена химическая модификация пиридиновой части их молекулы – перемещение метильной группы в положение 8 пиридо[1,2-a]пиримидинового ядра. Синтез целевых объектов исследования осуществлен реакцией соответствующих бензиламинов с этил-2-гидрокси-8-метил-4-оксо-4Н-пиридо[1,2-a]пиримидин-3-карбоксилатом, в свою очередь, полученным конденсацией 2-амино-4-метилпиридина (т. е. продукта с метильной группой в заведомо требуемом положении) с триэтилметантрикарбоксилатом. Строение синтезированных веществ подтверждено данными элементного анализа и спектроскопии 1Н ЯМР, а в случае оптически активных 1-фенилэтиламидов дополнительно еще и поляриметрически. Изучение анальгетических свойств всех N-(бензил)-2-гидрокси-8-метил-4-оксо-4Н-пиридо[1,2-a]пиримидин-3-карбоксамидов проведено на стандартной экспериментальной модели уксуснокислых корчей. При этом найдено, что предпринятая нами модификация сопровождается усилением биологической активности исключительно паразамещенных производных. Для углубленных испытаний в качестве нового потенциального анальгетика рекомендован 4-фторбензиламид, превосходящий по уровню специфического эффекта Пироксикам и Набуметон.Як один з можливих варіантів оптимізації біологічних властивостей N-(бензил)-2-гідрокси-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксамідів розглянуто хімічну модифікацію піридинової частини їх молекули – переміщення метильної групи у положення 8 піридо[1,2-a]піримідинового ядра. Синтез цільових об’єктів дослідження здійснено реакцією відповідних бензиламінів з етил-2-гідрокси-8-метил-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксилатом, у свою чергу, одержаним конденсацією 2-аміно-4-метилпіридину (тобто продукту з метильною групою в завідомо необхідному положенні) з триетилметантрикарбоксилатом. Будову синтезованих речовин підтверджено даними елементного аналізу та спектроскопії 1Н ЯМР, а у випадку оптично активних 1-фенілетиламідів додатково ще й поляриметрично. Вивчення аналгетичних властивостей усіх N-(бензил)-2-гідрокси-8-метил-4-оксо-4Н-піридо[1,2-a]піримідин-3-карбоксамідів проведено на стандартній експериментальній моделі оцтовокислих корчів. При цьому знайдено, що здійснена нами модифікація супроводжується посиленням біологічної активності виключно паразаміщених похідних. Для поглиблених випробовувань як новий потенційний аналгетик рекомен

Diode Based on Amorphous SiC

Diode structure on the basis of amorphous silicon carbide and p-type polycrystalline silicon (Eurosolar) were obtained with magnetron RF-nonreactive sputtering method from solid-phase target in argon atmosphere. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3365

Automated test analysis of main technological modes of stepless transmissions

Предложена методика по комплексной оценке, сравнению альтернативных вариантов и общая идеология автоматизированного конструирования бесступенчатых трансмиссий шахтных дизелевозов. Рассмотрен автоматизированный тестовый анализ основных технологических режимов работы бесступенчатых гидрообъемно-механических или электромеханических трансмиссий.The methodology for integrated evaluation, comparison of alternatives and the general ideology of automated construction of stepless transmissions are offered. The automated test analysis of the main technological modes of stepless hydrovolumetric mechanical or electromechanical transmissions is reviewed

Features of application of stepless hydrovolumetric mechanical transmissions

Наведено основні переваги й недоліки гідрооб’ємно-механічних трансмісій. Проаналізовано кінематичні та функціональні схеми двопотокових гідрооб’ємно‐механічних трансмісій. Доведено, що застосування безступінчастих трансмісій перспективне як на автомобілях, так і на шахтних дизелевозах.The basic advantages and disadvantages hydrovolumetric mechanical transmissions are given. Kinematic and functional scheme of double‐mechanical transmissions are analyzed. It is proved that the use of stepless transmissions is promising as in cars, and on mine diesel locomotives