Zr alloy protection against high-temperature oxidation: Coating by a double-layered structure with active and passive functional properties

In this work, a new concept of metal surface protection against degradation caused by high-temperature oxidation in water environment is presented. We were the first to create a double-layered coating consisting of an active and passive part to protect Zr alloy surface against high-temperature oxidation in a hot water environment. We investigated the hot steam corrosion of ZIRLO fuel cladding coated with a double layer consisting of 500 nm nanocrystalline diamond (NCD) as the bottom layer and 2 m chromium-aluminum-silicon nitride (CrAlSiN) as the upper layer. Coated and noncoated ZIRLO samples were exposed for 4 days at 400 °C in an autoclave (working water-cooled nuclear reactor temperature) and for 60 minutes at 1000 °C (nuclear reactor accident temperature) in a hot steam furnace. We have shown that the NCD coating protects the Zr alloy surface against oxidation in an active way: carbon from NCD layer enters the Zr alloy surface and, by changing the physical and chemical properties of the Zr cladding tube surface, limits the Zr oxidation process. In contrast, the passive CrAlSiN coating prevents the Zr cladding tube surface from coming into physical contact with the hot steam. The advantages of the double layer were demonstrated, particularly in terms of hot (accident-temperature) oxidation kinetics: in the initial stage, CrAlSiN layer with low number of defects acts as an impermeable barrier. But after a longer time (more than 20 minutes) the protection by more cracked CrAlSiN decreases. At the same time, the carbon from NCD strongly penetrates the Zr cladding surface and worsen conditions for Zr oxidation. For the double-layer coating, the underlying NCD layer mitigates thermal expansion, reducing cracks and defects in upper layer CrAlSiN

Diamond Coated LW-SAW Sensors-Study of Diamond Thickness Effect

This study focuses on the fabrication and characterization of Love wave surface acoustic wave (LW-SAW) sensors with a thin nano-crystalline diamond (NCD) coating with an integrated microfluidics system. The effect of diamond layer thickness on the acoustic wave phase velocity and the sensor’s sensitivity have been investigated experimentally and compared with theoretical simulations. The fabricated sensors have been tested with a several liquids using a home-made microfluidics system

Optical Contrast and Raman Spectroscopy Techniques Applied to Few-Layer 2D Hexagonal Boron Nitride

The successful integration of few-layer thick hexagonal boron nitride (hBN) into devices based on two-dimensional materials requires fast and non-destructive techniques to quantify their thickness. Optical contrast methods and Raman spectroscopy have been widely used to estimate the thickness of two-dimensional semiconductors and semi-metals. However, they have so far not been applied to two-dimensional insulators. In this work, we demonstrate the ability of optical contrast techniques to estimate the thickness of few-layer hBN on SiO2/Si substrates, which was also measured by atomic force microscopy. Optical contrast of hBN on SiO2/Si substrates exhibits a linear trend with the number of hBN monolayers in the few-layer thickness range. We also used bandpass filters (500–650 nm) to improve the effectiveness of the optical contrast methods for thickness estimations. We also investigated the thickness dependence of the high frequency in-plane E2g phonon mode of atomically thin hBN on SiO2/Si substrates by micro-Raman spectroscopy, which exhibits a weak thickness-dependence attributable to the in-plane vibration character of this mode. Ab initio calculations of the Raman active phonon modes of atomically thin free-standing crystals support these results, even if the substrate can reduce the frequency shift of the E2g phonon mode by reducing the hBN thickness. Therefore, the optical contrast method arises as the most suitable and fast technique to estimate the thickness of hBN nanosheets

Основні положення настанов по веденню хворих з алергією до коров'ячого молока. Частина V. Лікування алергії до коров'ячого молока

The article presents the sections 15, 16, 17, 18, 19 f the World Allergy Organization guidelines DRACMA (Diagnosis and Rationale for Action against Cow's Milk Allergy), which was the prototype for the creation of national guidelines for the management of patients with the cow milk allergy. These sections cover the issues concerning the main characteristics of the milk of different animals, which is used to replace cow's milk (section 15); ensuring nutritional value in the treatment of CMA (section 16); the choice of theratment formula in different clinical situations (section 17); GRADE&recommendations for CMA immunotherapy (section 18) and guidelines for research and implementation of DRACMA (section 19). Guidelines developed by the panel on the initiative of Ukrainian Allergy Organization, Ukrainian Organization of children gastroenterologists and nutritionists, Ukrainian Organization of immunologists, allergists and imunoreabilitologists and supported by the Ministry of Health of Ukraine. Key words: allergy, cow's milk, proteins, treatment.В статье представлены разделы 15, 16, 17, 18 и 19 руководства Всемирной организации аллергологов DRACMA (Diagnosis and Rationale for Action against Cow's Milk Allergy), ставшего прототипом для создания отечественного Руководства по ведению больных с аллергией к коровьему молоку. В этих разделах рассматриваются основные характеристики молока разных животных, которое используют для замены коровьего молока (глава 15); обеспечение пищевой ценности при лечении АКМ (глава 16); выбор лечебной смеси в различных клинических ситуациях (глава 17); Grade-рекомендации касательно иммунотерапии АКМ (глава 18) и рекомендации для исследований и внедрений DRACMA (глава 19). Рекомендации разработаны рабочей группой по инициативе Ассоциации аллергологов, Ассоциации детских гастроэнтерологов и нутрициологов, Ассоциации иммунологов, аллергологов и иммунореабилитологов Украины и при поддержке МЗ Украины. Ключевые слова: аллергия, коровье молоко, лечение.У статі наведено розділи 15, 16, 17, 18 та 19 керівництва Всесвітньої організації алергологів DRACMA (Diagnosis and Rationale for Action against Cow's Milk Allergy), що стало прототипом для створення вітчизняних Настанов по веденню хворих з алергією до коров'ячого молока (АКМ). У цих розділах розглядаються основні характеристики молока від різних тварин, яке використовують для заміни коров'ячого молока (розділ 15); забезпечення харчової цінності при лікуванні АКМ (розділ 16); вибору лікувальної суміші при різних клінічних ситуаціях (розділ 17); Grade-рекомендації стосовно імунотерапії АКМ (роздiл 18) та рекомендації для дослідження та впровадження DRACMA (розділ 19). Настанови розроблені робочою групою за ініціативи Асоціації алергологів, Асоціації дитячих гастроентерологів та нутриціологів, Асоціації імунологів, алергологів та імунореабілітологів України та за підтримки МОЗ України. Ключові слова: алергія, коров'яче молоко, лікування

Magnetical and optical properties of nanodiamonds can be tuned by particles surface chemistry: Theoretical and experimental study

© 2014 American Chemical Society. In this paper, new steps toward a better understanding and utilization of high-pressure high-temperature nanodiamonds (NDs) containing nitrogen-vacancy (NV) centers have been taken. NV--related long-term luminescence of oxygenated particles increased in comparison to plasma hydrogenated NDs' NV- luminescence. The optically detected NV- electron spin resonance process can be also significantly affected by ND termination. For H-terminated ND particles the NV- to NV0 conversion energy is lower than the NV- excitation energy, so that the delocalized triplet electrons can be more easily released from the original positions and drawn to the electron-attracting localities in the material. The final result of this study was application of luminescent NDs in cells, showing the detectability of luminescent NDs in a standard confocal microscope and ND subcellular distribution in the cells by TEM

Magnetical and optical properties of nanodiamonds can be tuned by particles surface chemistry: Theoretical and experimental study

© 2014 American Chemical Society. In this paper, new steps toward a better understanding and utilization of high-pressure high-temperature nanodiamonds (NDs) containing nitrogen-vacancy (NV) centers have been taken. NV--related long-term luminescence of oxygenated particles increased in comparison to plasma hydrogenated NDs' NV- luminescence. The optically detected NV- electron spin resonance process can be also significantly affected by ND termination. For H-terminated ND particles the NV- to NV0 conversion energy is lower than the NV- excitation energy, so that the delocalized triplet electrons can be more easily released from the original positions and drawn to the electron-attracting localities in the material. The final result of this study was application of luminescent NDs in cells, showing the detectability of luminescent NDs in a standard confocal microscope and ND subcellular distribution in the cells by TEM

La Patrie : journal quotidien, politique, commercial et littéraire

30 mars 18781878/03/30 (A38)