Structural, Mechanical and Erosion Properties of Yttrium Oxide Coatings by Axial Suspension Plasma Spraying for Electronics Applications

Yttrium oxide (Y₂O₃) coatings have been prepared by axial suspension plasma spraying with fine powders. It is clarified that the coatings have high hardness, low porosity, high erosion resistance against CF₄ -containing plasma and retention of smooth eroded surface. This suggests that the axial suspension plasma spraying of Y₂O₃ is applicable to fabricating equipment for electronic devices, such as dry etching. Surface morphologies of the slurry coatings with splats are similar to conventional plasma-sprayed Y₂O₃ coatings, identified from microstructural analysis. Dense coating structures with no lamellar boundaries have been seen, which is apparently different from the conventional coatings. It has also been found that crystal structure of the suspension coatings mainly composed of metastable monoclinic phase, whereas the powders and the conventional plasma spray coatings have stable cubic phase. Mechanism of coating formation by plasma spraying with fine powder slurries is discussed based on the results.     

Charge evaluation of EDLC for autonomous microgrid energy storage

Electric double layer capacitor (EDLC) is now playing more and more roles in microgrids for renewable energy storage due to its characteristic merits in high charging and high energy density. Different charging modes of EDLC are mainly studied in this paper. Compared with traditional constant-voltage and constant-current charging modes, constant-power charging mode (CPCM) ranks more reasonable positions for autonomous systems. Numerical calculations were presented for practical analysis, which was validated to be accurate enough and applicable by a simple case with PV/EDLC system configuration. Charging efficiency of different charging modes was also reviewed with strict mathematic deductions. Furthermore, trade-off problems, between charging time/efficiency/energy loss, were also investigated in brief for practical optimization of application occasions. For practical applications, how to utilize and manage the relationship of shifting modes in a reasonable way can be dealt with the actual requirements.     

Structure and magnetic properties of mono- and bi-layer graphene films on ultraprecision figured 4H-SiC(0001) surfaces

Monolayer and bilayer graphene films with a few hundred nm domain size were grown on ultraprecision figured 4H-SiC(0001) on-axis and 8 degrees -off surfaces by annealing in ultra-high vacuum. Using X-ray photoelectron spectroscopy (XPS), atomic force microscopy, reflection high-energy electron diffraction, low-energy electron diffraction (LEED), Raman spectroscopy, and scanning tunneling microscopy, we investigated the structure, number of graphene layers, and chemical bonding of the graphene surfaces. Moreover, the magnetic property of the monolayer graphene was studied using in-situ surface magneto-optic Kerr effect at 40 K. LEED spots intensity distribution and XPS spectra for monolayer and bilayer graphene films could become an obvious and accurate fingerprint for the determination of graphene film thickness on SiC surface.     

Visualization of deuterium flux and grain boundary diffusion in duplex stainless steel and Fe–30 % Ni alloy,using secondary ion mass spectrometry equipped with a Ga focused ion beam

Time of flight secondary ion mass spectrometry (TOF-SIMS) equipped with a high spatial resolution Ga focused ion beam (Ga-FIB) was applied to understand hydrogen diffusion and desorption behavior in duplex stainless steel and Fe–30 % Ni alloys. Deuterium was used as a tracer of hydrogen. Results showed that the secondary ion intensity from body-centered cubic (bcc) and face-centered cubic (fcc) Fe represents the flux of deuterium from the surface and the concentration of deuterium, respectively. The deuterium-depleted zone can be visualized from the interface between bcc and fcc phase to fcc Fe on the surface. Furthermore, direct visualization of the grain boundary diffusion of deuterium is also possible in fcc Fe–30 % Ni alloys, using Ga-FIB-TOF-SIMS.     

Cerebral sinus thrombosis in a patient with protein S deficiency: a case report

To investigate the role of occupation as a risk factor for hairy cell leukaemia a case-control study on 121 male, hairy cell leukaemia (HCL) patients, and 484 controls matched for age and sex, was conducted. We found significantly elevated risk for HCL among building painters (OR, 5.7; 95% CI, 1.6-20.8; based on six cases and four controls) and construction workers (OR, 3.3; CI, 1.2-9.2; based on seven cases and eight controls). Farming has been suggested as a risk factor in HCL. In this investigation farmers had an OR of 1.2 (CI, 0.6-2.3) and farm workers an OR of 1.5 (CI, 0.8-2.8). However, having ever worked in farming yielded an OR of 1.8 (CI, 1.1-2.9). Having grown up mainly in a rural area gave an OR of 1.4 (CI, 0.9-2.4). UV light has been suggested as a risk factor for non-Hodgkin's lymphoma (NHL). To evaluate the impact of UV exposure, classification of occupations as indoor, outdoor or mixed indoor/outdoor was made. Outdoor and mixed outdoor/indoor work yielded ORs of 2.3 (1.0-4.9) and 1.6 (1.0-2.5), respectively. When the effect of outdoor/indoor or mixed indoor/outdoor work was analysed using a scoring system the OR was 2.0 (CI, 0.9-4.4) for farmers compared with 0.8 (CI, 0.3-1.9) among non-farmers in the highest scoring group. There was no clear correlation between socioeconomic status as defined by the Swedish Socio-Economic Classification (SEI), and the risk of HCL. As many comparisons were made, the possibility of associations occurring by chance can not be excluded.     

Normalized longitudinal current distributions on microstrip lineswith finite strip thickness

An open microstrip line with finite strip thickness is numerically analyzed by the Green's function technique. The normalized longitudinal current distributions are systematically obtained for the cases of various shape and thickness ratios in the quasi-TEM approximation. The obtained results are illustrated in figures for three surfaces of the thick strip conductor, that is, the lower, side, and upper surfaces. The closed-form expressions are obtained for the normalized longitudinal current distributions by taking a best fit to theoretical results     

Crystal ice formation of solution and its removal phenomena on inclined cooled plate

Experimental studies for freezing phenomena of ethylene glycol solution on an inclined polyvinyl-chloride plate have been performed. It is found that the crystal ice formed on the inclined cooled plate is removed from the plate surface due to a buoyancy force acting on the crystal ice. It is shown that the crystal ice grows in a shape of sheet by joining with neighboring ice and that the ice slides along the inclined surface when it is removed. The onset of the ice removal condition is related to the cooling heat flux at the surface. The ice removal occurs more easily for the plate of large inclination than that of a small one.