Irradiation-induced ductilization in the Zr-based metallic glasses

Crystalline metals in the nuclear energy system often suffer from the radiation-induced embrittlement which is resulted from the interaction between dislocation motions and the irradiation-induced changes in microstructures. This transition to the brittle failure may lower the mechanical stability of the irradiated components, posing significant threats to the operation and security of the entire mechanical system. In contrast to the crystalline metals, amorphous alloys, often called metallic glasses, have a different plasticity mechanism that does not involve the dislocation motion and hence are expected to exhibit the different irradiation effects on the mechanical from their crystalline counterparts. In this study, we investigated the mechanical properties of the Zr57Nb5Al10Cu15.4Ni12.6 metallic glass specimens irradiated by the protons through compression experiments on the nanopillars with 200 nm and 400 nm diameters at various strain rates. The energies of the protons were properly chosen between 30 keV and 200 keV to ensure the nearly uniform radiation damage depth profile to ~1.5 micron. The experimental results were also corroborated by the molecular dynamic simulation to fully understand the atomic level processes associated with the proton irradiation and mechanical behavior in the metallic glasses

GraNNDis: Efficient Unified Distributed Training Framework for Deep GNNs on Large Clusters

Graph neural networks (GNNs) are one of the most rapidly growing fields within deep learning. According to the growth in the dataset and the model size used for GNNs, an important problem is that it becomes nearly impossible to keep the whole network on GPU memory. Among numerous attempts, distributed training is one popular approach to address the problem. However, due to the nature of GNNs, existing distributed approaches suffer from poor scalability, mainly due to the slow external server communications. In this paper, we propose GraNNDis, an efficient distributed GNN training framework for training GNNs on large graphs and deep layers. GraNNDis introduces three new techniques. First, shared preloading provides a training structure for a cluster of multi-GPU servers. We suggest server-wise preloading of essential vertex dependencies to reduce the low-bandwidth external server communications. Second, we present expansion-aware sampling. Because shared preloading alone has limitations because of the neighbor explosion, expansion-aware sampling reduces vertex dependencies that span across server boundaries. Third, we propose cooperative batching to create a unified framework for full-graph and minibatch training. It significantly reduces redundant memory usage in mini-batch training. From this, GraNNDis enables a reasonable trade-off between full-graph and mini-batch training through unification especially when the entire graph does not fit into the GPU memory. With experiments conducted on a multi-server/multi-GPU cluster, we show that GraNNDis provides superior speedup over the state-of-the-art distributed GNN training frameworks

Effect of Annealing Environment on the Performance of Sol-Gel-Processed ZrO2 RRAM

We investigate the annealing environment effect on ZrO2-based resistive random-access memory (RRAM) devices. Fabricated devices exhibited conventional bipolar-switching memory properties. In particular, the vacuum-annealed ZrO2 films exhibited larger crystallinity and grain size, denser film, and a relatively small quantity of oxygen vacancies compared with the films annealed in air and N2. These led to a decrease in the leakage current and an increase in the resistance ratio of the high-resistance state (HRS)/low-resistance state (LRS) and successfully improved non-volatile memory properties, such as endurance and retention characteristics. The HRS and LRS values were found to last for 104 s without any significant degradation. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.1

Environmental implications of a sandwich structure of a glass fiber-reinforced polymer ship

This study presents the findings related to the selection of composite structures for materials with respect to the effectiveness of their lightweight design and environmental impact during the raw material manufacturing phases. The primary raw materials considered were glass fiber, PVC for the core, and polyester resin. In addition, using the same design conditions, such as bottom load, impregnation rate, and production method, a reverse engineering approach was applied to transform the sandwich structure into a single laminate structure, allowing for a comparative quantitative analysis of the reduction in lightweight effectiveness. The results revealed that the sandwich structure was approximately 42.44% lighter than that of the reverse-engineered single-skin laminate structure. A life cycle evaluation was also conducted, and the raw materials required for hull construction were analyzed with SimaPro 9.0 as the LCA tool software, Ecoinvent 3 for inventory analysis, and the ReCiPe 2016 method for environmental impact analysis. PVC foam and polyester resin were identified as highly hazardous for both human and environmental health, whereas fiberglass exhibited the lowest emissions among the materials considered. Furthermore, the sandwich structure offered greater environmental advantages across all damage endpoints than the single-skin laminates. This finding highlights the potential of sandwich structures as a more sustainable option. In practical terms, enhancing the bending strength of the core material in sandwich structures can reduce the thickness of the outer and inner skin members, thereby reducing the weight of ships and significantly reducing potential health risks to human worker health, harm to the ecosystem, and resource demands

Ultra-Short Pulsed Laser Annealing Effects on MoS2 Transistors with Asymmetric and Symmetric Contacts

The ultra-short pulsed laser annealing process enhances the performance of MoS 2 thin film transistors (TFTs) without thermal damage on plastic substrates. However, there has been insufficient investigation into how much improvement can be brought about by the laser process. In this paper, we observed how the parameters of TFTs, i.e., mobility, subthreshold swing, I on /I off ratio, and V th , changed as the TFTs’ contacts were (1) not annealed, (2) annealed on one side, or (3) annealed on both sides. The results showed that the linear effective mobility (µeff_lin) increased from 13.14 [cm 2 /Vs] (not annealed) to 18.84 (one side annealed) to 24.91 (both sides annealed). Also, I on /I off ratio increased from 2.27 x 10 5 (not annealed) to 3.14 x 10 5 (one side annealed) to 4.81 x 10 5 (both sides annealed), with V th shifting to negative direction. Analyzing the main reason for the improvement through the Y function method (YFM), we found that both the contact resistance (R c ) and the channel interface resistance (R ch ) improves after the pulsed laser annealings under different conditions. Moreover, the Rc enhances more dramatically than the R ch does. In conclusion, our picosecond laser annealing improves the performance of TFTs (especially, the R c ) in direct proportion to the number of annealings applied. The results will contribute to the investigation about correlations between the laser annealing process and the performance of devices. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.1

Conformal and Ultra Shallow Junction Formation Achieved Using a Pulsed-Laser Annealing Process Integrated With a Modified Plasma Assisted Doping Method

Recently, a shallow and conformal doping profile is required for promising 3D structured devices. In this study, we deposited the dopant phosphorus (P) using modified plasma assisted doping (PaD) followed by an annealing process to electrically activate the dopants. A rapid thermal annealing process (RTP) was the first approach tested for activation but it resulted in a deep junction ( > 35 nm). To reduce the junction depth, we tried the fiash lamp annealing process (FLP) to shorten the annealing time. We also predicted the annealing temperature by numerical thermal analysis, which reached 1,020 degrees C. However, the FLP resulted in a deep junction (similar to 30 nm), which was not shallow enough to suppress short channel effects. Since an even shorter annealing process was required to form a ultra-shallow junction, we tried the laser annealing process (LAP) as a promising alternative. The LAP, which had a power density of 0.3 J/cm(2), increased the surface temperature up to 1,100 degrees C with a shallow isothermal layer. Using the LAP, we achieved a USJ with an activated surface dopant concentration of 3.86 x 10(19) cm(-3) and a junction depth of 10 nm, which will allow further scaling-down of devices.1

Sol-gel Processed Yttrium-doped SnO2 Thin Film Transistors

Y-doped SnO2 thin film transistors were successfully fabricated by means of sol-gel process. The effect of Y concentration on the structural, chemical, and electrical properties of sol-gel-processed SnO2 films was investigated via GIXRD, SPM, and XPS; the corresponding electrical transport properties of the film were also evaluated. The dopant, Y, can successfully control the free carrier concentration by suppressing the formation of oxygen vacancy inside SnO2 semiconductors due to its lower electronegativity and SEP. With an increase of Ywt%, it was observed that the crystallinity and oxygen vacancy concentration decreased, and the operation mode of SnO2 thin film transistor changed from accumulation (normally on) to enhancement mode (normally off) with a positive Vth shift. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.1

Clinical and Echocardiographic Findings of Newly Diagnosed Acute Decompensated Heart Failure in Elderly Patients

PURPOSE: Elderly patients (pts) (EPs; ≥ 65 years old) with newly diagnosed-acute decompensated heart failure (ND-ADHF) have not yet been studied. The aim of the present study was to investigate clinical characteristics, including echocardiographic findings and prognosis, for EPs with ND-ADHF and to compare those with non-elderly pts (NEPs). MATERIALS AND METHODS: We retrospectively investigated 256 pts (144 males, 63.0 ± 14.8 years old) who were admitted to our hospital between January 2005 and March 2009 with ND-ADHF. Clinical characteristics and echocardiographic parameters were analyzed in EPs (n = 135, 58 males) and NEPs (n = 121, 86 males). RESULTS: In intergroup comparison, female gender, diabetes mellitus, previous stroke and hypertension were more common in EPs. Body mass index (22.3 ± 4.5 vs. 24.0 ± 4.4 kg/m(2)), estimated glomerular filtration rate (54.8 ± 24.3 vs. 69.2 ± 30.7 mL/min/m(2)), C-reactive protein (28.5 ± 46.9 vs. 7.6 ± 11.6 mg/dL), hemoglobin (12.3 ± 2.1 vs. 13.6 ± 2.3 g/dL) and N-terminal pro-brain natriuretic peptide level (10,538.2 ± 10,942.3 vs. 6,771.0 ± 8,964.7 pg/mL) were significantly different (p < 0.05 for all). Early mitral inflow velocity to early diastolic mitral annular velocity (E/E') was significantly higher in EPs than in NEPs (21.2 ± 9.4 vs. 18.0 ± 8.9, p < 0.05). During follow-up (44.7 ± 14.5 months), there were no significant differences in in-hospital mortality, re-hospitalization and cardiovascular mortality between EPs and NEPs (p = NS for all). CONCLUSION: EPs with ND-ADHF have different clinical characteristics and higher LV filling pressure when compared with NEPs. However, the clinical outcomes for NEPs with ND-ADHF are not necessarily more favorable than those for EPs.ope

The Long-Term Effect of Cancer on Incident Stroke: A Nationwide Population-Based Cohort Study in Korea

Background and Purpose: Despite the recent growing interest in the cancer–stroke association, the long-term effect, and organ-specific association with stroke incidence in subjects with cancer have not been clearly defined.Methods: Data were obtained from the Korean National Health Insurance Service National Sample Cohort database between 2002 and 2015. To investigate the effects of cancer on stroke incidence, subjects were classified into cancer and non-cancer groups based on the period after cancer diagnosis and origin organ of cancer. To minimize the effects of selection bias, we performed a propensity score matching analysis with covariates of demographic data, vascular risk factors, antithrombotics use and statin use. Incident stroke was diagnosed based on operational definition and classified into ischemic stroke and hemorrhagic stroke.Results: Data of 20,707 subjects with cancer and 675,594 without cancer were analyzed for 7 follow-up years. The subjects with cancer had higher risk of any stroke (subdistribution hazard ratio [SHR], 1.13; 95% confidence interval [CI], 1.02–1.26; p = 0.0181) than those without cancer. Similar trend was found for ischemic stroke (SHR, 1.17; 95% CI, 1.05–1.31; p = 0.0054), but not for hemorrhagic stroke. The risk of stroke was increased in subjects with cancer in the digestive organ, respiratory and intrathoracic organ, and “others (such as breast and female and male reproductive organs)” in 3 years; however, the association disappeared thereafter except those with “others” cancer. Chemotherapy increased the risk of ischemic stroke (SHR 1.21; 95% CI, 1.03–1.41).Conclusions: Cancer increases the risk of stroke at 3 years after the diagnosis of cancer, and the effect was maintained for 7 years. The association between cancer and stroke incidence depends on the organ from which the cancer originated and chemotherapy

Psychiatric Comorbidity in Korean Children and Adolescents with Attention-Deficit Hyperactivity Disorder: Psychopathology According to Subtype

It is well-known that more than 50% of attention-deficit hyperactivity disorder (ADHD) cases also have comorbid psychiatric disorders. We evaluated the comorbid psychopathology of Korean children and adolescents with ADHD using a standardized diagnostic instrument. The Korean Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL-K) was administered and completed in 105 patients who had been referred to the outpatient and inpatient clinics at the Samsung Medical Center from March 2004 to May 2005. All of the cases were diagnosed as ADHD according to DSM-IV criteria. We analyzed their clinical characteristics and psychiatric comorbidities, and assessed the correlation of any comorbidity with gender, age and ADHD subtype. Among our 105 participants, 70 (66.7%) subjects were diagnosed with combined-type ADHD, 22 (21.0%) were the predominantly inattentive type, only 1 (1.0%) was determined to have the predominantly hyperactive-impulsive type of ADHD, and 12 (11.4%) were classified as not otherwise specified (NOS) ADHD. Eighty (76.2%) subjects had at least one comorbid disorder such as oppositional defiant disorder (n = 53, 50.5%), anxiety disorders (n = 35, 33.3%) and affective disorders (n = 15, 14.3%). Our patients ranged in age from five to 16 years. Among the factors including gender, age, and ADHD subtype, ADHD subtype was the only one significant to comorbidity in our study. The results of this study suggest that psychiatric comorbidity in Korean children with ADHD is similar to the results of previous studies in western countries. Out of all the ADHD subtypes, the combined-type group had a significantly higher ratio of comorbid disorders and psychopathologies