In this letter, we demonstrate high-performance AlGaN/GaN Schottky barrier diodes (SBDs) on Si substrate with a recessed-anode structure for reduced turn-on voltage VON. The impact of the surface ...roughness after the recessed-anode formation on device characteristics is investigated. An improved surface condition can reduce the leakage current and enhance the breakdown voltage simultaneously. A low turn-on voltage of only 0.73 V can be obtained with a 50-nm recess depth. In addition, the different lengths of Schottky extension acting like a field plate are investigated. A high reverse breakdown voltage of 2070 V and a low specific ON-resistance of 3.8 mΩ · cm 2 yield an excellent Baliga's figure of merit of 1127 MW/cm 2 , which can be attributed to the low surface roughness of only 0.6 nm and also a proper Schottky extension of 2 μm to alleviate the peak electric field intensity in the SBDs.
Background
Sodium-glucose co-transporter 2 (SGLT2) inhibitors has been shown with cardiovascular benefit in type 2 diabetes mellitus (T2DM) patients. However, its osmotic diuresis still concern ...physicians who may look for possible electrolyte imbalance. We therefore aimed to investigate electrocardiographic (ECG) changes associated with SGLT2 inhibitors.
Methods
Electronic medical records from Chang Gung Research Database between January 1, 2001 and January 31, 2019 were searched for patients with ECG reports and patients on an oral hypoglycemic agent (OHA). We then separate these T2DM patients with EKG into those taking either SGLT2 inhibitors or non-SGLT2 inhibitors. We excluded patients with OHA use <28 days, age <18 years, baseline ECG QTc > 500 ms, and ECG showing atrial fibrillation or atrial flutter. Propensity score matching (PSM) was performed between groups by age, sex, comorbidities, and medications (including QT prolonging medications). Conditional logistic regression and Firth's logistic regression for rare events were employed to compare the difference between SGLT2 and non-SGLT2 inhibitor patients.
Results
After exclusion criteria and PSM, there remained 1,056 patients with ECG on SGLT2 inhibitors and 2,119 patients with ECG on non-SGLT2 inhibitors in the study. There were no differences in PR intervals, QT prolongations by Bazett's or Fridericia's formulas, new onset ST-T changes, new onset CRBBB or CLBBB, and ventricular arrhythmia between the group of patients on SGLT2 inhibitors and the group of patients on non-SGLT2 inhibitors. There were no differences between the two groups in terms of cardiovascular death and sudden cardiac death. In addition, there were no differences between the two groups in terms of electrolytes.
Conclusions
Compared with T2DM patients on non-SGLT2 inhibitors, there were no differences in PR interval, QT interval, ST-T changes, bundle-branch block, or ventricular arrhythmia in the patients on SGLT2 inhibitors. There were no differences in cardiovascular mortality between these two groups. In addition, there were no electrolyte differences between groups. SGLT2 inhibitors appeared to be well-tolerated in terms of cardiovascular safety.
Poly(ether sulfone)-based anion exchange membranes (AEM)s containing dense quaternary ammonium cations were prepared for anion exchange membrane fuel cell applications. Poly(ether sulfone)s, ...XMePh-Z, derived from a new aromatic diol, 4,4′-dihydroxy-2,2′,6,6′-tetra(p-tolyl)diphenyl ether containing four tolyl substituents, 4,4′-(hexafluoroisopropylidene)diphenol (HFDP), and bis(4-fluorophenyl)sulfone (BFS), were prepared and functionalized via photoinitiated bromination on tolyl substituents followed by quaternization. The photoinitiated bromination is so selective that the reaction occurred only on the methyl groups of tolyl substituents without polymer main chain degradation. The IEC values of poly(ether sulfone)-based AEMs, from 1.21 to 2.11 mmol/g, can be controlled by the degree of bromination. These membranes with water uptake from 40 to 120% exhibited hydroxide conductivity at 80 °C from 13 to 45 mS/cm. By using different ratios of monomers with and without tolyl substituents, the distribution of cationic groups can be controlled. AEMs with a smaller amount of tolyl-substituted monomer had their cationic sites located more closely when IEC values were the same. This allowed membranes with the same IEC values exhibited lower water uptake, better dimensional stability, and higher hydroxide conductivity. These AEMs also demonstrated good alkaline stability. In the case of 40MePh-1.72 with an IEC value of 1.72 mmol/g, the hydroxide conductivity and IEC remained at 78 and 81% of their original values, respectively, after 720 h of an alkaline stability test. A single fuel cell based on 40MePh-1.72 exhibited an open circuit voltage of 1.03 V and peak power density of 291 mW/cm2 at 60 °C using platinum loading of 0.5 mg/cm2. It performed better than a single fuel cell based on commercially available FAA-3 with an open circuit voltage of 1.02 V and peak power density of 226 mW/cm2 under the same testing conditions.
In this letter, we demonstrate high-performance AlGaN/GaN Schottky barrier diodes (SBDs) on Si substrate with a recessed-anode structure for reduced turn-on voltage Formula Omitted. The impact of the ...surface roughness after the recessed-anode formation on device characteristics is investigated. An improved surface condition can reduce the leakage current and enhance the breakdown voltage simultaneously. A low turn-on voltage of only 0.73 V can be obtained with a 50-nm recess depth. In addition, the different lengths of Schottky extension acting like a field plate are investigated. A high reverse breakdown voltage of 2070 V and a low specific ON-resistance of 3.8 Formula Omitted yield an excellent Balig's figure of merit of 1127 MW/cm2, which can be attributed to the low surface roughness of only 0.6 nm and also a proper Schottky extension of 2 Formula Omitted to alleviate the peak electric field intensity in the SBDs.
In this paper, we present an energy-efficient acceler-ator chip which supports high-quality CNN-based computational imaging applications at 4K UItra-UD 30fps. To address the huge requirement of DRAM ...bandwidth and computing energy, an overlapped stripe inference flow and a structure-sparse \text{CONV}3\mathrm{x}3 engine are proposed respectively. The former reduces DRAM bandwidth to 0.81-1.74 GB/s when supporting high-quality CNN inference with 16 to 29 layers at 4K UItra-UD 30fps. The latter reduces computing complexity by 40% without noticeable quality degradation, e.g. 0.02-0.03 dB of PSNR drop. More specifically, it uses only 4.9 intrinsic TOPS of computing capability at 200 MHz to approach the quality of dense models which demand up to 8.2 TOPS. In addition, a coarse-grained reconfigurable datapath is designed to support diverse Applications including super-resolution, denoising, and style transfer with high hardware efficiency. Fabricated in 40nm CMOS, this chip achieves 4.6-8.3 TOP/W of energy efficiency for high-quality computational imaging applications. We also implement an FPGA-aided system to demonstrate real-time processing for the diverse applications supported by the fabricated chip.
A series of diblock-copolymers were synthesized through anionic polymerization of styrene and tert-butyl methacrylate (tBuA) with different monomer ratios, and analogous block-copolymeric derivatives ...(PS-b-PAA)s with monofunctional carboxylic acid groups were obtained by further hydrolyzation as hydrogen-bonded (H-bonded) proton donors. Via H-bonded interaction, these diblock-coplymeric donors (PS-b-PAA)s were incorporated with luminescent mono-pyridyl/bis-pyridyl acceptors to form single/double H-bonded supramolecules, that is, H-bonded side-chain/cross-linking copolymers, respectively. The supramolecular architectures formed by donor polymers and light-emitting acceptors were influenced by the ratio of acid blocks in the diblock copolymeric donors and the type of single/double H-bonded light-emitting acceptors. Their thermal and luminescent properties can be adjusted by H-bonds, and more than 100 nm of red-shifted photoluminescence (PL) emissions were observed, which depend on the degrees of the H-bonding interactions. Self-assembled phenomena of amphiphilic dibolck copolymers and their H-bonded complexes were confirmed by TEM micrographs, and supramolecular microphase separation of spherical micelle-like morphology was demonstrated to affect the photophysical properties. Polymer light-emitting diode (PLED) devices containing H-bonded complexes showed electroluminescence (EL) emissions of 503-560 nm under turn-on voltages of 7.5-9.0 V, maximum power efficiencies of 0.23-0.37 cd/A (at 100 mA/cm²), and maximum luminances of 318-519 cd/m² (around 25 V).
碩士
國立清華大學
電子工程研究所
103
The material characteristics of Gallium Nitride used in the power device applications are superior than silicon owing to the wide bandgap (~3.4 eV), high critical electric field ...(3.4 MV/cm), high electron saturation velocity (2*107 cm/s), and high thermal conductivity (2.3 W/cm．K). Recently, many publications related to the AlGaN/GaN-on-Silicon Schottky Barrier Diodes (SBDs) have been discussed. One of the most critical issues is lowering the turn-on voltage owing to the wide bandgap nature of the material, which can increase the conduction loss and seriously degrade the efficiency of circuits and systems.
This thesis presents the simulation and measurement results. In the simulation, the Silvaco TCAD software is used to simulate the turn-on voltage and e-field distribution for that with/without anode recess. Also, by considering two different contacts (Schottky and ohmic) with different silicon substrate doping and with/without AlN layer (between GaN and Silicon), the vertical distribut
The stereoselectivity and yield in glycosylation reactions are paramount but unpredictable. We have developed a database of acceptor nucleophilic constants (Aka) to quantify the nucleophilicity of ...hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure high reproducibility and accuracy. A diverse range of glycosylation donors and acceptors with well‐defined reactivity and promoters were organized and processed by the designed software program “GlycoComputer” for prediction of glycosylation reactions without involving sophisticated computational processing. The importance of Aka was further verified by random forest algorithm, and the applicability was tested by the synthesis of a Lewis A skeleton to show that the stereoselectivity and yield can be accurately estimated.
A so‐called “GlycoComputer” program has been developed to foresee and predict the yield and stereoselectivity of glycosylation reactions based on the properties of various donors, acceptors, activation systems and solvents. The program statistically analyzes and compares the relative reactivity value (RRV) of donors and the acceptor nucleophilic constant (Aka) of acceptors.
Accelerated Solid Phase Glycan Synthesis: ASGS Bakhatan, Yasmeen; Alshanski, Israel; Chan, Chieh‐Kai ...
Chemistry : a European journal,
July 6, 2023, Letnik:
29, Številka:
38
Journal Article
Recenzirano
Odprti dostop
Solid phase synthesis is the most dominant approach for the preparation of biological oligomers as it enables the introduction of monomers iteratively. Accelerated solid phase synthesis of biological ...oligomers is crucial for chemical biology, but its application to the synthesis of oligosaccharides is not trivial. Solid‐phase oligosaccharide assembly is a slow process performed in a variety of conditions and temperatures, requires an inert gas atmosphere, and demands high excess of glycosyl donors. The process is done in special synthesizers and poor mixing of the solid support increases the risk of diffusion‐independent hydrolysis of the activated donors. High shear stirring is a new way to accelerate solid phase synthesis. The efficient mixing ensures that reactive intermediates can diffuse faster to the solid support thereby increasing the kinetics of the reactions. We report here a stirring‐based accelerated solid‐phase oligosaccharide synthesis. We harnessed high shear mixing to perform diffusion‐dependent glycosylation in a short reaction time. We minimized the use of glycosyl donors and the need to use an inert atmosphere. We showed that by tailoring the deprotection and glycosylation conditions to the same temperature, assembly steps are performed continuously, and full glycosylation cycles are completed in minutes.
Fast and efficient: High shear stirring accelerates glycan synthesis on solid support and enables efficient and fast glycosylation that competes even with glycosyl donor hydrolysis in an open vessel.
Many artificial intelligence (AI) edge devices use nonvolatile memory (NVM) to store the weights for the neural network (trained off-line on an AI server), and require low-energy and fast I/O ...accesses. The deep neural networks (DNN) used by AI processors 1,2 commonly require p-layers of a convolutional neural network (CNN) and q-layers of a fully-connected network (FCN). Current DNN processors that use a conventional (von-Neumann) memory structure are limited by high access latencies, I/O energy consumption, and hardware costs. Large working data sets result in heavy accesses across the memory hierarchy, moreover large amounts of intermediate data are also generated due to the large number of multiply-and-accumulate (MAC) operations for both CNN and FCN. Even when binary-based DNN 3 are used, the required CNN and FCN operations result in a major memory I/O bottleneck for AI edge devices.
