Polycrystalline Diamond Thin Films for Advanced Applications

The technological achievements in diamond thin film synthesis over the past decade subsequently led to the utilization of outstanding diamond properties and development of a wide range of applications in various fields of engineering. However, since most chemical vapour deposition (CVD) diamond films are polycrystalline, their characteristics strongly depend on their microstructure. As the number of possible applications for polycrystalline CVD diamond increases, there is constant development and enhancement of the film properties. Polycrystalline diamond in the form of thin films delivers further advantages over thicker polycrystalline layer, e.g., smoother surface, less deposition time and less light absorption. Furthermore, besides the relevant diamond properties, the suitability for applications also depends on various material parameters such as substrate nature, substrate dimensions, possibility of non-planar geometries, surface morphology, electrical conductivity, capability of device fabrication, electrochemical properties and cost

PREPARING OF THE CHAMELEON COATING BY THE ION JET DEPOSITION METHOD

Preparation of chameleon coatings using an Ionized Jet Deposition (IJD) technique is reported in the present paper. IJD is a new flexible method for thin film deposition developed by Noivion, Srl. The chameleon coatings are thin films characterised by a distinct change of their tribological properties according to the external conditions. The deposited films of SiC and TiN materials were examined by the Raman spectroscopy, SEM and XPS. The results of the Raman spectroscopy have proved an amorphous structure of SiC films. The data from XPS on TiN films have shown that the films are heavily oxidized, but also prove that the films are composed of TiN and pure Ti. The SEM provided information about the size of grains and particles constituting the deposited films, which is important for tribological properties of the films. Deposition of the chameleon coating is very complex problem and IJD could be ideal method for preparation of this coating

Nanocrystalline diamond protects Zr cladding surface against oxygen and hydrogen uptake : Nuclear fuel durability enhancement

In this work, we demonstrate and describe an effective method of protecting zirconium fuel cladding against oxygen and hydrogen uptake at both accident and working temperatures in water-cooled nuclear reactor environments. Zr alloy samples were coated with nanocrystalline diamond (NCD) layers of different thicknesses, grown in a microwave plasma chemical vapor deposition apparatus. In addition to showing that such an NCD layer prevents the Zr alloy from directly interacting with water, we show that carbon released from the NCD film enters the underlying Zr material and changes its properties, such that uptake of oxygen and hydrogen is significantly decreased. After 100–170 days of exposure to hot water at 360 °C, the oxidation of the NCD-coated Zr plates was typically decreased by 40%. Protective NCD layers may prolong the lifetime of nuclear cladding and consequently enhance nuclear fuel burnup. NCD may also serve as a passive element for nuclear safety. NCD-coated ZIRLO claddings have been selected as a candidate for Accident Tolerant Fuel in commercially operated reactors in 2020

Inhibition of extracellular ice crystals growth for testing the cryodamaging effect of intracellular ice in a model of ram sperm ultra-rapid freezing

ABSTRACTWe aimed to test the common belief, that as the sperm cell is the smallest cell in an organism and, therefore, it contains a small amount of intracellular water, the intracellular ice should not strongly affect the sperm cell during the cryopreservation. To investigate the effect of intracellular ice, we developed a novel approach of ram spermatozoa ultra-rapid freezing with the inhibition of the growth of extracellular ice crystals during freezing. In our approach, ram sperm was supplemented with cell-impermeable synthetic ice blocker 1,4-Cyclohexanediol, leaving a sample unsupplemented as a control. Sperm in cryostraws were ultra-rapidly frozen, and then thawed. We hypothesized, that only in the case when the intracellular ice plays the role in the cryodamage, the post-freezing intactness of spermatozoa frozen in the presence of extracellular ice inhibitors should be equal (or even less) to the intactness of spermatozoa frozen without extracellular inhibitors. No statistically significant difference (p = 0.98) was observed between the post-freezing intactness of sperm ultra-rapidly frozen in the presence of 1,4-Cyclohexanediol and the intactness of sperm frozen without 1,4-Cyclohexanediol. We concluded that the intracellular ice plays the role in sperm cryodamage, at least in the model of ram sperm ultra-rapid freezing

Timing of ICSI with Respect to Meiotic Spindle Status

The aim of this study was to evaluate the efficiency of using meiotic spindle (MS) visibility and relative position to the polar body (PB) as indicators of oocyte maturation in order to optimize intracytoplasmic sperm injection (ICSI) timing. This was a cohort study of patients younger than 40 years with planned ICSI, the timing of which was determined by MS status, compared with those without MS evaluation. The angle between PB and MS and MS visibility were evaluated by optical microscope with polarizing filter. Oocytes with MS evaluation were fertilized according to MS status either 5–6 h after ovum pick-up (OPU) or 7–8 h after OPU. Oocytes without MS evaluation were all fertilized 5–6 h after OPU. For patients over 35 years visualization of MS influenced pregnancy rate (PR): 182 patients with MS visualization had 32% PR (58/182); while 195 patients without MS visualization had 24% PR (47/195). For patients under 35 years, visualization of MS did not influence PR: 140 patients with MS visualization had 41% PR (58/140), while 162 patients without MS visualization had 41% PR (66/162). Visualization of MS therefore appears to be a useful parameter for assessment of oocyte maturity and ICSI timing for patients older than 35