A digital driving technique for an 8 b QVGA AMOLED display using modulation

Active-matrix organic LED (AMOLED) is one of the most promising contenders for next-generation displays. However, the VT-shift issue in thin-film transistors (TFT) has to be addressed to enable wide deployment. Voltage programming and current programming are well-known VT-shift-compensation techniques for analog driving. However, they all need more than 4 TFTs per pixel, which increases the panel complexity and decreases yield and aperture ratio. Recently, a VT-shift compensation technique that uses a 2TFT-1C pixel in an analog driving AMOLED has been reported. However, it requires OLED supply voltage programming, and shows a 14% variation in OLED current after VT-shift compensation, which is not enough for high-definition applications. Digital driving has been proposed as an alternative to mitigate the VT-shift issue with a simple pixel structure and to provide flexibility to the driver design. In this paper shows the pixel structures for voltage programming, current programming and digital driving. While the gate of the driving TFT (M2) is in the high state, the voltage across M2 is very small due to the large current-driving capability of a TFT as compared with an OLED. Hence, the current through the OLED is dominated by the supply voltage (PVDD), and minimally affected by the variations in TFT characteristics. Digital driving is also useful for true dark-level expression since the OLED can be completely turned off for black gray levels

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

Patient Perception of Natural Orifice Transluminal Endoscopic Surgery in an Endoscopy Screening Program in Korea

Purpose Natural orifice transluminal endoscopic surgery (NOTES) is a new method of accessing intracavitary organs in order to minimize pain by avoiding incisions in the body wall. The aim of this study is to determine patients' acceptance of NOTES in Korea and to compare their views about laparoscopic surgery and NOTES for benign and malignant diseases. Materials and Methods The target number of total subjects was calculated to be 540. The subjects were classified into 18 sub-groups based on age groups, gender, and history of prior surgery. The questionnaire elicited information about demographic characteristics, medical check-ups, diseases, endoscopic and surgical histories, marital status and childbirth, the acceptance of NOTES, and the preferred routes for NOTES. In addition, the subjects chose laparoscopic surgery or NOTES for a hypothetical cholecystectomy and rectal cancer surgery, and responded to questions regarding the acceptable complication rate of NOTES, the appropriate cost of NOTES, and the reason(s) why they did not select NOTES. Results: 486 of 540 patients (90.0%) who agreed to participate in this study completed the questionnaire. NOTES was preferred by the following patients: elderly; a history of treatment due to a disease; having regular check-ups; and a history of an endoscopic procedure (p<0.05). The most preferred route for NOTES was the stomach (67.1%). Eighty-four percent of the patients choosing NOTES responded that the complication rate of the new surgical method should be the same or lower than laparoscopic surgery. Vague anxiety over a new surgical method was the most common reason why NOTES was not selected in benign and malignant diseases (64% and 73%), respectively. Conclusion: Patients appear to be interested in the potential benefits of NOTES and would embrace it if their concerns about safety are met. We believe that qualified surgical endoscopists can meet these safety concerns, and that NOTES development has the potential to flourish

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

Satellite-based monitoring of an open-pit mining site using Sentinel-1 advanced radar interferometry: A case study of the December 21, 2020, landslide in Toledo City, Philippines

Understanding the causal factors and mechanisms behind catastrophic landslides and debris flows is crucial for accurate forecasting and disaster risk reduction. Synthetic aperture radar (SAR) data and interferometric SAR (InSAR) technologies provide valuable information for early warning systems’ landslide and debris flow detection and monitoring strategies. This paper applied the Sentinel-1 Persistent Scatterer InSAR (PSInSAR) technique to detect and monitor precursory slope movements over the open-pit mining site in Toledo City, Cebu Island, in the Philippines. The results show that the slope showed instabilities between December 30, 2019, to December 12, 2020, before the actual failure on December 21, 2020. The landslide initiation zone moved with velocities exceeding –10 mm/yr and reaching –90 mm/yr. The topography and morphology of the mining site contributed to the cut slope instabilities. The mining operations and hydrometeorological conditions during the analysis period aggravated the situation, leading to the cut slope failure. Overall, with favorable slope geometry, surface characteristics, and SAR data availability, the Sentinel-1 PSInSAR technique can serve as a landslide early warning system tool and aid decision-making in an actively operating open-pit mine and other landscapes

Nuclear Factor Erythroid-Derived 2-Like 2-Induced Reductive Stress Favors Self-Renewal of Breast Cancer Stem-Like Cells via the FoxO3a-Bmi-1 Axis

Aims: A subpopulation of cancer cells, termed cancer stem cells (CSCs), has stemness properties, such as self-renewal and differentiation, which drive cancer recurrence and tumor resistance. CSCs possess enhanced protection capabilities to maintain reduced intracellular levels of reactive oxygen species (ROS) compared with nonstem-like cancer cells. This study investigated whether reductive stress could regulate self-renewal activity in breast CSCs. Results: We found that manifestation of stemness in breast cancer stem-like cells was associated with an elevated production of reduced glutathione (GSH) maintained by upregulation of glutamate cysteine ligase catalytic subunit (GCLC) and consequently, lowered ROS levels. This was accompanied by upregulation of phospho-AMP-activated protein kinase, FoxO3a, and Bmi-1. Notably, expression of nuclear factor erythroid-derived 2-like 2 (Nrf2) protein was substantially increased in cells undergoing sphere formation. We noticed that expression of Bmi-1 was inhibited after introduction of Nrf2 short interfering RNA into MCF-7 mammosphere cells. Silencing of Nrf2 expression suppressed the xenograft growth of subcutaneously or orthotopically injected human breast cancer cells. Innovation: Association between Nrf2 and self-renewal signaling in CSCs has been reported, but the underlying molecular mechanism remains largely unresolved. This study demonstrates the Nrf2-mediated signaling pathway in maintenance of reductive stress in breast CSCs. Conclusion: Nrf2 overactivation in breast CSCs upregulates GCLC expression and consequently enhances GSH biosynthesis with concurrent reduction in intracellular ROS accumulation, thereby provoking the reductive stress. The consequent upregulation of nuclear FoxO3a and its binding to the promoter of the gene encoding Bmi-1 account for the self-renewal activity of breast cancer stem-like cells and their growth in a xenograft mouse model.

Effect of multiple debris flow countermeasures on flow characteristics and topographic changes through real-scale experiment

In this study, to investigate the effect of multiple countermeasure on the flow characteristics of debris flows, a real-scale experiment was conducted in a natural gully by reproducing a debris flow with a installation of multiple countermeasures. In addition, the topographic changes before and after experiment by debris flow were investigated using UAV-LiDAR. Based on the experiment results, the effect of multiple countermeasures and the topographic changes against the gully erosion and deposition caused by debris flow were also analyzed. The installation of multiple countermeasures significantly decreased the frontal velocity of debris flow. Furthermore, the countermeasure induced the deposition of debris material on the back of the countermeasure

Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density

Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Whl(-1) at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology.