In this brief, the influence of high-density traps at the SiO 2 /SiC interface on short-channel effects was investigated, and a model describing channel length dependence of the threshold voltage ...(i.e., the gate voltage at a given drain current) is proposed. First, we determined the densities of interface states and fixed charge in 4H-SiC n-channel MOSFET by fitting the calculated gate characteristics to the experimental data, and acquired the density of trapped electrons from the obtained results. Then, we calculated the threshold voltage by considering that the majority of the trapped electrons are emitted near the drain end due to formation of a depletion layer. The channel length dependence of the threshold voltage calculated by the proposed model showed a good agreement with the experimental results even when the definition of threshold voltage was changed. The present model taking account of the fixed charge and of the trapped electron charge enables the estimation of the threshold voltage in the 4H-SiC short-channel MOSFETs.
Although both o-toluidine and o-anisidine are known as aromatic amines with bladder carcinogenicity, the specific metabolites involved in carcinogenesis are still unclear. Here, we examined the ...toxicological effects of head-to-tail dimers of o-toluidine and o-anisidine, 2-methyl-N4-(2-methylphenyl) benzene-1,4-diamine (MMBD) and 2-methoxy-N4-(2-methoxyphenyl) benzene-1,4-diamine (MxMxBD), respectively, in rats. Six-week-old male F344 rats were orally administered MMBD, MxMxBD, o-toluidine, and o-anisidine at a dose of 100 mg/kg/day for 28 days. Rats administered 400 mg/kg o-toluidine and 600 mg/kg/day o-anisidine were set as high-dose groups for comparison. Histopathology and immunohistochemistry for γ-H2AX, a DNA damage biomarker, and bladder stem cell markers, including aldehyde dehydrogenase 1A1 (ALDH1A1), were performed. MMBD and MxMxBD caused different toxicities than their monomers, inducing hepatotoxicity such as vacuolar degeneration but not splenic lesions due to methemoglobinemia. Bladder lesions, including urothelial hyperplasia, were observed in the high-dose o-toluidine and o-anisidine groups, whereas no obvious changes were induced in the low-dose groups or their dimers. Although γ-H2AX formation was significantly increased by o-toluidine and o-anisidine treatment, γ-H2AX formation did not differ among the MMBD, MxMxBD, and control groups. Notably, immunohistochemistry revealed marked increases in ALDH1A1 expression in the bladder urothelium of the MMBD and MxMxBD groups and in the o-toluidine and o-anisidine groups, suggesting that the two dimers may contribute to the bladder carcinogenic effects of o-toluidine and o-anisidine to some extent. The degrees of bladder lesions and γ-H2AX formation did not correlate with the amount of unchanged o-toluidine and o-anisidine in urine, indicating the presence of other metabolites responsible for these findings.
Oxidation of silicon carbide (SiC) is known to induce defects at the interface of the SiO2/SiC system. NO-annealing is a standard industrial method of nitridation, but oxidation may progress during ...NO-nitridation, which may generate interface defects. Here, we propose a new method of fabricating SiO2/SiC metal-oxide-semiconductor (MOS) devices: sputter deposition of SiO2 in an Ar/N2 gas mixture followed by high-temperature CO2-post deposition annealing to form SiO2 and incorporate nitrogen at the interface while suppressing oxidation of the SiC. We obtained the nitrogen depth profile by performing x-ray photoelectron spectroscopy and confirmed that most of the nitrogen atoms exist at the abrupt interface. While maintaining a low interface state density and good insulating property, we demonstrated much improved reliability of MOS devices compared to conventional NO-annealed samples, thanks to the well-designed SiO2/SiC interface by the proposed method.
To assess low-contrast areas such as plaque and coronary artery stenosis, coronary computed tomography angiography (CCTA) needs to provide images with lower noise without increasing radiation doses.
...To develop a deep learning-based noise-reduction method for CCTA using four-dimensional noise reduction (4DNR) as the ground truth for supervised learning.
\We retrospectively collected 100 retrospective ECG-gated CCTAs. We created 4DNR images using non-rigid registration and weighted averaging three timeline CCTA volumetric data with intervals of 50 ms in the mid-diastolic phase. Our method set the original reconstructed image as the input and the 4DNR as the target image and obtained the noise-reduced image via residual learning. We evaluated the objective image quality of the original and deep learning-based noise-reduction (DLNR) images based on the image noise of the aorta and the contrast-to-noise ratio (CNR) of the coronary arteries. Further, a board-certified radiologist evaluated the blurring of several heart structures using a 5-point Likert scale subjectively and assigned a coronary artery disease reporting and data system (CAD-RADS) category independently.
DLNR CCTAs showed 64.5% lower image noise (
< 0.001) and achieved a 2.9 times higher CNR of coronary arteries than that in original images, without significant blurring in subjective comparison (
> 0.1). The intra-observer agreement of CAD-RADS in the DLNR image was excellent (0.87, 95% confidence interval = 0.77-0.99) with original CCTAs.
Our DLNR method supervised by 4DNR significantly reduced the image noise of CCTAs without affecting the assessment of coronary stenosis.
PDF
