Direct formic acid fuel cells (DFAFCs) stand out for portable electronic devices owing to their ease of handling, abundant fuel availability, and high theoretical open circuit potential. However, the practical application of DFAFCs is hindered by the unsatisfactory performance of electrocatalysts for the sluggish anodic formic acid oxidation reaction (FAOR). Palladium (Pd) based nanomaterials have shown promise for FAOR due to their highly selective reaction mechanism, but maintaining high electrocatalytic durability remains challenging.
View Article and Find Full Text PDFIn this study, a capacitorless one-transistor dynamic random-access memory (1T-DRAM) cell based on a polycrystalline silicon dual-gate metal-oxide-semiconductor field-effect transistor with a fin-shaped structure was optimized and analyzed using technology computer-aided design simulation. The proposed 1T-DRAM demonstrated improved memory characteristics owing to the adoption of the fin-shaped structure on the side of gate 2. This was because the holes generated during the program operation were collected on the side of gate 2, allowing an expansion of the area where the holes were stored using the fin-shaped structure.
View Article and Find Full Text PDFThe self-heating effects (SHEs) on the electrical characteristics of the GaN MOSFETs with a stacked TiO/SiN dual-layer insulator are investigated by using rigorous TCAD simulations. To accurately analyze them, the GaN MOSFETs with SiN single-layer insulator are conducted to the simulation works together. The stacked TiO/SiN GaN MOSFET has a maximum on-state current of 743.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
August 2021
In this study, a high-performance vertical gallium nitride (GaN) power transistor is designed by using two-dimensional technology computer-aided design simulator. The vertical GaN transistor is used to analyze the DC/DC boost converter. The systems requiring high voltages of 1000 V or more, such as electric vehicles, need wide devices to achieve a high breakdown voltage when using conventional power devices.
View Article and Find Full Text PDFIn this paper, we present a capacitorless one transistor dynamic random access memory (1T-DRAM) based on a polycrystalline silicon (poly-Si) double gate MOSFET with grain boundaries (GBs). Several studies have been conducted to implement 1T-DRAM using poly-Si. This is because poly-Si has the advantage of low-cost fabrication and can be stacked.
View Article and Find Full Text PDFIn this paper, a 1T-DRAM based on the junctionless field-effect transistor (JLFET) with a silicon-germanium (SiGe) and silicon (Si) nanotube structure was designed and investigated by using technology computer-aided design (TCAD) simulations. Utilizing bandgap engineering to make a quantum well in the core-shell structure, the storage pocket is formed by the difference in bandgap energy between SiGe and Si. By applying different voltage conditions at the inner gate and outer gate, excess holes are generated in the storage region by the band-to-band tunneling (BTBT) mechanism.
View Article and Find Full Text PDFIn this paper, a 1T-DRAM based on the junctionless field-effect transistor (JLFET) with an ultrathin polycrystalline silicon layer was designed and investigated by using technology computer-aided design simulation (TCAD). The application of a negative voltage at the control gate results in the generation of holes in the storage region by the band-to-band tunneling (BTBT) effect. Memory characteristics such as sensing margin and retention time are affected by the doping concentration of the storage region, bias condition of the program, and length of the intrinsic region.
View Article and Find Full Text PDFIn this paper, we adopt the vertical core-shell nanowire field-effect transistors based on the Silicon-germanium (SiGe)/strained-silicon (strained-Si) layer as a method to improve the performance of the CMOS logic inverter by using technology computer aided design simulation. The lattice constant mismatch between the core region and the shell region causes the global strain of the Si region of the shell, which in turn changes the Si parameters. This phenomenon effects on the improvement the electrical characteristics in the -type MOSFET (MOSFET).
View Article and Find Full Text PDFJ Nanosci Nanotechnol
November 2020
In this paper, we demonstrate the characteristics of a complementary metal-oxide-semiconductor (CMOS) logic inverter based on a polycrystalline-silicon (poly-Si) layer with a single grain boundary (GB). The proposed nanoscale CMOS logic inverter had been constructed on a poly-Si layer with a GB including four kind of traps at the center of the channel. The simulation variables are the acceptor-like deep trap (ADT), the donor-like deep trap (DDT), the acceptor-like shallow trap (AST) and the donor-like shallow trap (DST).
View Article and Find Full Text PDFIn this work, a capacitorless one-transistor embedded dynamic random-access memory based on a metal-oxide-semiconductor field-effect transistor with a double-polysilicon layer structure has been proposed and investigated using technology computer-aided design simulation. By using the grain boundary for hole storage, a higher sensing margin of 4.35 / is achieved compared to that without using the grain boundary.
View Article and Find Full Text PDFIn this work, we present a normally-off recessed-gate AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistor (MIS-HEMT) using a TiO₂/SiN dual gate-insulator. We analyzed the electrical characteristics of the proposed device and found that the dual gate-insulator device achieves higher on-state currents than the device using a SiN gate-insulator because the high-k insulator layer of the dual gate-insulator improves the gate-controllability. The device using a TiO₂/SiN gate-insulator shows better gate leakage current characteristics than the device with only TiO₂ gate-insulator because of the high quality SiN gate-insulator.
View Article and Find Full Text PDFMicromachines (Basel)
October 2019
In this paper, a germanium-based gate-metal-core vertical nanowire tunnel field effect transistor (VNWTFET) has been designed and optimized using the technology computer-aided design (TCAD) simulation. In the proposed structure, by locating the gate-metal as a core of the nanowire, a more extensive band-to-band tunneling (BTBT) area can be achieved compared with the conventional core-shell VNWTFETs. The channel thickness (), the gate-metal height (), and the channel height () were considered as the design parameters for the optimization of device performances.
View Article and Find Full Text PDFIn this work, an InGaAs/GaAsSb-based -type gate-all-around (GAA) arch-shaped tunneling fieldeffect transistor (TFET) was designed and analyzed using technology computer-aided design (TCAD) simulations. The device performance was investigated in views of the on-state current (), subthreshold swing (), and / ratio. For high current drivability, InGaAs/GaAsSb heterojunction is used to form the broken bandgap.
View Article and Find Full Text PDFThis paper report a junctionless fin-type field-effect-transistor based capacitorless dynamic random access memory using three-dimensional technology computer-aided design simulations. The proposed 1T-DRAM is made up of a silicon germanium storage region surrounding a silicon fin. When the two materials form a heterojunction, a potential well is formed by the band discontinuity which carriers can be stored.
View Article and Find Full Text PDFThe effect of interface traps on InGaAs-based vertical gate-all-around (GAA) tunneling field-effect transistors (TFETs) has been investigated using technology computer-aided design (TCAD) simulation. The interface traps distributed within different energy levels () in the energy bandgap of a semiconductor material exhibit various influences on the device performances. In this work, InGaAs-based TFETs are simulated to analyze the effects on the on-state current (), off-state current (), threshold voltage (), subthreshold swing (), and the ambipolar characteristics according to and type of the interface traps.
View Article and Find Full Text PDFWe present a capacitorless one-transistor dynamic random-access memory (1T-DRAM) based on a Si/SiGe heterojunction double-gate MOSFET. In the proposed 1T-DRAM, the program process is based on band-to-band tunneling (BTBT) between gate 1 and gate 2 regions, and a sensing margin is defined by the amount of excess holes stored in the SiGe body region. Therefore, the sensing margin and retention time were affected by SiGe in the body region.
View Article and Find Full Text PDFIn this study, the effect of an AlGaN back-barrier on the electrical characteristics of InAlGaN/GaN high electron mobility transistors (HEMTs) was investigated. The dependence of the thickness and the Al composition of the AlGaN back-barrier on the off-state current (I) of the devices was investigated. An InAlGaN/GaN HEMT with an AlGaN back-barrier of thickness 20 nm exhibited lower because of the carrier confinement effect, which was caused by the back-barrier.
View Article and Find Full Text PDFPurpose: To examine the effects of a home-based exercise program on quality of life (QOL), psychological health, and the level of physical activity (PA) in colorectal cancer survivors.
Methods: Seventy-one colorectal cancer survivors were randomized into either a home-based exercise group (N = 37) or control group (N = 34). The home-based exercise program included unsupervised walking, stationary bike, or swimming for aerobic exercise, as well as resistance exercise DVDs, a pedometer, and an exercise log.
In this study, one-transistor dynamic random-access memory (1T-DRAM) based on a symmetric double-gate Si junctionless transistor is proposed using technology computer-aided design simulation. The proposed device uses double gates that play different roles in realizing 1T-DRAM operation. Gate 1 is used as a switching node, and Gate 2 is used as a storage node.
View Article and Find Full Text PDFIdiopathic restrictive cardiomyopathy (RCMP) has not been fully understood because this disease is difficult to diagnose. The present study aimed to assess the clinical profile and outcome of idiopathic RCMP from a multicenter cohort.This investigation is a retrospective study of consecutive patients with idiopathic RCMP at 10 centers in Korea between 1990 and 2010.
View Article and Find Full Text PDFBackground: This study aimed to evaluate the association of the lifelong duration of breast feeding with metabolic syndrome (MetS) and its components in Korean parous women aged 19-50 years.
Materials And Methods: A total of 4724 participants from the Korean National Health and Nutritional Survey were included. Subjects were divided into four groups according to the duration of breast feeding: ≤5, 6-11, 12-23, or ≥24 months groups.
Two cases of hematological malignancies were reported in an industrial radiography company over a year, which were reasonably suspected of being consequences of prolonged exposure to ionizing radiation because of the higher incidence than expected in the general population. We analyzed chromosomal aberrations in the peripheral blood lymphocytes from the other workers who had been working under similar circumstances as the patients in the company. Among the subjects tested, 10 workers who belonged to the highest band were followed up periodically for 1.
View Article and Find Full Text PDFObjectives: A vertebral compression fracture (VCF) is characterized by back pain and fracture of a vertebral body on spinal radiography. VCFs of the thoraco lumbar spine are common in the elderly. In general, appropriate analgesics should be prescribed to reduce pain and, thus, promote early mobilization.
View Article and Find Full Text PDFBackground: The purpose of this study was to investigate the changes in airway pressure and arterial oxygenation between ventilation modes during one-lung ventilation (OLV) in patients undergoing thoracic surgery.
Methods: We enrolled 27 patients for thoracic surgery with OLV in the lateral decubitus position. The subjects received various modes of ventilation in random sequences during surgery, including volume-controlled ventilation (VCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) with a tidal volume (TV) of 8 ml/kg of actual body weight.
Background: Spondylolisthesis is the major cause of refractory low back pain. There are many studies of the surgical treatment of spondylolisthesis, but few of conservative treatments. There is also no optimal conservative treatment protocol, however, low back pain caused by low-grade spondylolisthesis is controlled with non-surgical pain management.
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