299 results on '"Hyungjun Kim"'
Search Results
2. Predictive modelling of level IIb lymph node metastasis in oral squamous cell carcinoma
- Author
-
Sung Hwa Lee, In Ho Cha, Woong Nam, Dongwook Kim, Hyunwoo Yang, Nak Hoon Son, and Hyungjun Kim
- Subjects
Oncology ,Male ,medicine.medical_specialty ,Multivariate analysis ,Science ,Diseases ,Article ,Metastasis ,Medical research ,Internal medicine ,medicine ,Humans ,Lymph node ,Neoplasm Staging ,Retrospective Studies ,Cancer ,Multidisciplinary ,Models, Statistical ,business.industry ,Squamous Cell Carcinoma of Head and Neck ,Univariate ,Nomogram ,Middle Aged ,medicine.disease ,Squamous carcinoma ,Survival Rate ,Dissection ,Nomograms ,medicine.anatomical_structure ,Risk factors ,Lymphatic Metastasis ,Lymph Node Excision ,Medicine ,Female ,Mouth Neoplasms ,Neoplasm Recurrence, Local ,business - Abstract
The aim of the present study was to examine the conditions, characteristics, and risk factors of level IIb lymph node metastases in oral squamous cell carcinoma and to formulate surgical criteria for level IIb lymph node dissection. We analyzed clinical and pathological records for 541 oral squamous carcinoma patients in relation to level IIb metastasis. Univariate and multivariate analyses were performed to detect risk factors for level IIb lymph node metastasis; a predictive model was built based on multivariate analysis and tested in a validation group. Univariate and multivariate analyses using the training group indicated that level IIa metastasis and Lymphovascular permeation (LVP) were two independent risk factors for level IIb lymph node metastasis. This model was built and tested in a validation group, the area under the curve being 0.697 (P
- Published
- 2021
3. Carbon-ion radiotherapy in osteosarcoma of the mandible: a case report
- Author
-
Tae-Wook Ha, Min Yeong Youn, Dongwook Kim, Slmaro Park, and Hyungjun Kim
- Subjects
Osteosarcoma ,medicine.medical_specialty ,Chemotherapy ,Radiotherapy ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Mandible ,Case Report ,Magnetic resonance imaging ,Heavy Ion Radiotherapy ,medicine.disease ,Head and neck neoplasms ,Radiation therapy ,Biological property ,medicine ,Carbon Ion Radiotherapy ,Heavy ion radiotherapy ,Surgery ,Radiology ,Oral Surgery ,business - Abstract
Carbon-ion radiotherapy (CIRT) is on the rise as a treatment choice for malignant tumor. Compared to conventional radiotherapy, particle beams have different physical and biological properties. Particle beam provides a low entry dose, deposits most of the energy at the endpoint of the flight path, and forms an asymptotic dose peak (the “Bragg peak”). Compared to protons, carbon with its larger mass decreases beam scattering, resulting in a sharper dose distribution border. We report a 50-year-old male who underwent CIRT without surgical resection on osteosarcoma of the mandible. After CIRT, the patient’s pain was gone, and the malignant mass remained stable with accompanying necrosis. Nine months later, however, magnetic resonance imaging demonstrated progression of the left mandibular osteosarcoma with pulmonary metastases. After multidisciplinary discussion, concurrent chemoradiotherapy was conducted. While necrotic bone segments came out of the mandible during subsequent periodic outpatient visits, the tumor itself was stable. Thirty months after his first visit and diagnosis, the patient is waiting for chemotherapy. Although CIRT is superior in treating radioresistant hypoxic disease, CIRT is in its infancy, so care must be taken for its indications and complications.
- Published
- 2021
4. Synthesis and Application of AgBiS2 and Ag2S Nanoinks for the Production of IR Photodetectors
- Author
-
Yusuke Oshima, Hyungjun Kim, Tatsuya Nakazawa, Hiroki Sato, Dong-Hyun Kim, and Jusang Park
- Subjects
Photocurrent ,Photoluminescence ,Materials science ,business.industry ,Chalcogenide ,General Chemical Engineering ,Photodetector ,Nanoparticle ,General Chemistry ,Article ,chemistry.chemical_compound ,Chemistry ,chemistry ,Quantum dot ,Optoelectronics ,business ,QD1-999 - Abstract
Nanoinks composed of quantum dots (QDs) are applied in light-receiving devices and light-emitting devices such as solar cells and displays. However, since the most widely used QDs, PbS and CdS, are toxic and environmentally concerning, alternative materials need to be developed. We synthesized and analyzed Ag chalcogenide nanoparticles, including AgBiS2 and Ag2S nanoparticles, which are eco-friendly materials. AgBiS2 and Ag2S QD films were prepared by spin-coating nanoparticle solutions and subsequent heat treatment. The effects of the heat treatment on residual ligands and photoluminescence were determined by surface analysis. The photocurrent response of the AgBiS2 and Ag2S QD films was measured in the near-infrared region, and the effect of the heat treatment temperature was investigated. The results indicate that AgBiS2 and Ag2S are prospective materials for near-infrared photodetectors.
- Published
- 2021
5. Wide-field optical coherence tomography deviation map for early glaucoma detection
- Author
-
Hae Min Park, Han Woong Lim, So Yeon Moon, Hyungjun Kim, Mincheol Seong, Hyo Chan Jeong, Hyunsoo Cho, Won June Lee, and Junhong Park
- Subjects
0301 basic medicine ,medicine.medical_specialty ,genetic structures ,Glaucoma ,Clinical settings ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Optical coherence tomography ,Ophthalmology ,Medicine ,medicine.diagnostic_test ,Pixel ,Receiver operating characteristic ,business.industry ,Early glaucoma ,medicine.disease ,Wide field ,eye diseases ,Sensory Systems ,030104 developmental biology ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,sense organs ,business ,Optic disc - Abstract
Background/aimsThis study aimed to establish a wide-field optical coherence tomography (OCT) deviation map obtained from swept-source OCT (SS-OCT) scans. Moreover, it also aimed to compare the diagnostic ability of this wide-field deviation map with that of the peripapillary and macular deviation maps currently being used for the detection of early glaucoma (EG).MethodsFour hundred eyes, including 200 healthy eyes and 200 eyes with EG were enrolled in this retrospective observational study. Patients underwent a comprehensive ocular examination, including wide-field SS-OCT (DRI-OCT Triton; Topcon, Tokyo, Japan). The individual wide-field scan was converted into a uniform template using the fovea and optic disc centres as fixed landmarks. Subsequently, the wide-field deviation map was obtained via the comparison between individual wide-field data and a normative wide-field database that had been created by combining images of healthy eyes into a uniform template in a previous study. The ability of the new wide-field deviation map to distinguish between EG and healthy eyes was assessed by comparing it with conventional deviation maps based on the area under the receiver operating characteristic curve (AUC).ResultsThe wide-field deviation map obtained using the normative wide-field database showed the highest diagnostic ability for the diagnosis of EG (AUC=0.980 and 961 for colour-coded pixels presenting ConclusionThe wide-field SS-OCT deviation map exhibited good performance for distinguishing between eyes with EG and healthy eyes. The visualisation of the wider damaged area on the wide-field deviation map could be useful for the diagnosis of EG in clinical settings.
- Published
- 2021
6. BACES Score for Predicting Mortality in Nontuberculous Mycobacterial Pulmonary Disease
- Author
-
Hyunsook Hong, Nakwon Kwak, Jae-Joon Yim, Noeul Kang, Yunjoo Im, Byung Woo Jhun, and Hyungjun Kim
- Subjects
Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Scoring system ,biology ,business.industry ,Pulmonary disease ,Critical Care and Intensive Care Medicine ,biology.organism_classification ,03 medical and health sciences ,0302 clinical medicine ,030228 respiratory system ,Predictive value of tests ,Internal medicine ,medicine ,Nontuberculous mycobacteria ,030212 general & internal medicine ,business ,Cohort study - Abstract
Rationale: Because the prognosis of nontuberculous mycobacterial pulmonary disease varies, a scoring system predicting mortality is needed.Objectives: We aimed to develop a novel scoring system to ...
- Published
- 2021
7. PE-ALD of Ge1−xSxamorphous chalcogenide alloys for OTS applications
- Author
-
Seung-Min Chung, Hyung Keun Kim, Taeyoon Lee, Minkyu Lee, Seok Man Hong, Sijung Yoo, Myoungsub Kim, Youngjun Kim, Tae-Hoon Kim, and Hyungjun Kim
- Subjects
010302 applied physics ,Materials science ,Chalcogenide ,business.industry ,Band gap ,02 engineering and technology ,General Chemistry ,Plasma ,021001 nanoscience & nanotechnology ,01 natural sciences ,Threshold voltage ,Amorphous solid ,Atomic layer deposition ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,Materials Chemistry ,Optoelectronics ,Thin film ,0210 nano-technology ,business ,Scaling - Abstract
Three-dimensional (3D) cross-point (X-point) technology, including amorphous chalcogenide-based ovonic threshold switching (OTS) selectors, is bringing new changes to the memory hierarchy for high-performance computing systems. To prepare for future 3D X-point memory scaling, we studied the plasma-enhanced atomic layer deposition (PE-ALD) of Ge1−xSx amorphous chalcogenide alloy thin films, the selection of which was motivated by their high optical bandgap and wide amorphous forming regions. The PE-ALD Ge1−xSx thin films were synthesized using a GeCl4 precursor and H2S plasma reactant, and their self-limited growth characteristics were studied in detail as a function of the exposure time of the ALD steps, temperature, and plasma power. The PE-ALD GeS2 thin film showed an RMS roughness of 0.29 nm and good conformality in the vertical 3D structure. Moreover, the OTS behavior of GeS2 and Ge2S3 mushroom-type devices with a 50 nm bottom electrode contact (BEC) were investigated as well as the trade-off relationship between the threshold voltage (1.9–6.2 V) and the normalized off current (20–250 nA) based on scaling the film thickness down from 30 nm to 5 nm. In particular, the GeS2 device showed a higher threshold field (∼3.1 MV cm−1) and lower normalized off current characteristics than the Ge2S3 device due to the higher trap density (2.1 × 1021 cm−3), according to the modified Poole–Frenkel (PF) model. The results achieved by this PE-ALD research on this novel binary GeS2 amorphous chalcogenide for OTS applications will contribute to the development of future 3D cross-point memory scaling.
- Published
- 2021
8. Operando Stability of Platinum Electrocatalysts in Ammonia Oxidation Reactions
- Author
-
Haesol Kim, Woong Lee, Chang Hyuck Choi, Man Ho Han, Jiwon Seo, Cheolho Jeon, Kug-Seung Lee, Woojin Yang, Joonhee Moon, Hyung Suk Oh, Keun Hwa Chae, Hyungjun Kim, Sang Gu Ji, and Donghyun Kim
- Subjects
010405 organic chemistry ,business.industry ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Redox ,Catalysis ,0104 chemical sciences ,Ammonia ,chemistry.chemical_compound ,chemistry ,Alternative energy ,Platinum ,business - Abstract
Ammonia has recently received considerable attention as an alternative energy carrier and a carbon-neutral fuel. In this future energy scenario, the ammonia oxidation reaction (AOR) is a pivotal pr...
- Published
- 2020
9. Effect of Cyclic Compressive Forces on New Bone Formation during the Distraction Period in Mandibular Distraction Osteogenesis Using a Microactuator-Generated Distractor
- Author
-
Jong-Tae Park, Jung Yul Cha, Hyun-Jin Kwon, Hee Jin Kim, and Hyungjun Kim
- Subjects
Orthodontics ,business.industry ,education ,Significant difference ,030230 surgery ,Compression (physics) ,behavioral disciplines and activities ,03 medical and health sciences ,Bone volume fraction ,Apposition ,0302 clinical medicine ,Mandibular distraction ,030220 oncology & carcinogenesis ,Long period ,Distraction ,Medicine ,Surgery ,Bone formation ,business ,psychological phenomena and processes - Abstract
Background The traditional method of distraction required a long period until the new bone was fully fused. This study aimed to evaluate the effect of cyclic and repetitive compressive force on new bone formation by applying a newly designed microactuator-generated distractor compared with the traditional distraction protocol. Methods The distraction devices were applied to the right and left mandibles of eight mature beagles, four of which were allocated to the experimental group and the other four to the control group. After a 5-day latency period, in the experimental group, 1.5-mm distraction and 0.5-mm compression were alternately applied every 12 hours; and in the control group, 0.5-mm distraction was repeated every 12 hours to perform a total of 7-mm mandibular lengthening. After an 8-week consolidation period, microstructure analysis using micro-computed tomography and histologic evaluations were performed. Results Bone volume fraction and trabecular number were significantly higher in the experimental group. Trabecular thickness did not show a significant difference, and trabecular separation was significantly higher in the control group. The measurement of new bone was significantly higher in the experimental group, but the difference in mineral apposition rate between the experimental and control groups was not statistically significant. Conclusions This study has revealed that applying cyclic compressive and tensile forces during the distraction period induces better new bone formation than repetitive distraction alone. In addition, the new distraction device produced reliable distraction results during the experiment.
- Published
- 2020
10. Reductive Electrophotocatalysis: Merging Electricity and Light To Achieve Extreme Reduction Potentials
- Author
-
Hyunwoo Kim, Song Lin, Tristan H. Lambert, and Hyungjun Kim
- Subjects
Materials science ,business.industry ,Chemistry ,Aryl ,Radical ,Photoredox catalysis ,General Chemistry ,Photochemistry ,010402 general chemistry ,Borylation ,01 natural sciences ,Biochemistry ,Article ,Catalysis ,Ion ,0104 chemical sciences ,Power (physics) ,Reduction (complexity) ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Excited state ,Electricity ,Process engineering ,business - Abstract
We describe a new electrophotocatalytic strategy that harnesses the power of light and electricity to generate an excited radical anion with a reducing potential of –3.2 V vs. SCE, which can be used to activate substrates with very high reduction potentials (Ered ~ –1.9 to –2.9 V). The resultant aryl radicals can be engaged in various synthetically useful transformations to furnish arylboronate, arylstannane, and biaryl products.
- Published
- 2020
11. The effect of two locally administered anti-resorptive agents on bone regeneration in a rat fibula model: Alendronate and 15-deoxy-Δ12,14-prostaglandin J2
- Author
-
Joo Young Hong, Jung Woo Nam, Jin Il Kwon, and Hyungjun Kim
- Subjects
medicine.medical_specialty ,Programmed cell death ,Anabolism ,business.industry ,Regeneration (biology) ,medicine.medical_treatment ,030206 dentistry ,Bisphosphonate ,Bone resorption ,Resorption ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Internal medicine ,Medicine ,Surgery ,Oral Surgery ,Fibula ,Bone regeneration ,business - Abstract
Bisphosphonates are well-known drugs as inhibitors of bone resorption acting on inducing programmed cell death of osteoclasts. However, many in vitro studies report that optimal concentration of the bisphosphonate affects not only osteoclasts but also osteoblasts, that is, it induces the anabolic effects of osteoblasts. Recently reported 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is an endogenous ligand of peroxisome proliferator-activated receptor-gamma, with an inhibitory activity on bone loss. Researchers have also suggested that 15d-PGJ2 has the ability to reduce bone destruction and as the possibility of regeneration of bone. The purpose of this study is to demonstrate the anabolic effect of two anti-resorptive materials, alendronate and 15d-PGJ2, in a critical sized segmental defect model of rat fibula. The regenerated bone on the operative site was assessed through gross, radiographic (plain X-ray, and micro-computed tomography), histomorphologic evaluation, and statistical analysis. Consequently, the locally applied alendronate prevented resorption of grafted materials, and had a positive effect on bone regeneration with positive micro-architectural modification of the surrounding bone, although this study did not verify a significant capacity of bone regeneration of 15d-PGJ2 and instead only shed a light on its possibility.
- Published
- 2019
12. Improved Sensitivity in Schottky Contacted Two-Dimensional MoS2 Gas Sensor
- Author
-
Jusang Park, Youngjun Kim, Nan Cho Oh, Hyungjun Kim, Soo Min Lee, Sang Koo Kang, and Hi Deok Lee
- Subjects
Electrode material ,Materials science ,business.industry ,Schottky barrier ,Schottky diode ,02 engineering and technology ,Chemical vapor deposition ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Responsivity ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,General Materials Science ,Electronics ,0210 nano-technology ,business ,Sensitivity (electronics) ,Molybdenum disulfide - Abstract
Two-dimensional (2D) transition-metal dichalcogenides have attracted significant attention as gas-sensing materials owing to their superior responsivity at room temperature and their possible application as flexible electronic devices. Especially, reliable responsivity and selectivity for various environmentally harmful gases are the main requirements for the future chemiresistive-type gas sensor applications. In this study, we demonstrate improved sensitivity of a 2D MoS2-based gas sensor by controlling the Schottky barrier height. Chemical vapor deposition process was performed at low temperature to obtain layer-controlled 2D MoS2, and the NO2 gas responsivity was confirmed by the fabricated gas sensor. Then, the number of MoS2 layers was fixed and the types of electrode materials were varied for controlling the Schottky barrier height. As the Schottky barrier height increased, the NO2 responsivity increased, and it was found to be effective for CO and CO2 gases, which had little reactivity in 2D MoS2-b...
- Published
- 2019
13. Assessment of Changes in Global Domestic Water Use and Economic Value
- Author
-
Sobhan Afraz, Taikan Oki, and Hyungjun Kim
- Subjects
Water resources ,Global issue ,Economic assessment ,Natural resource economics ,Human life ,Value (economics) ,Business ,Water use ,Water scarcity - Abstract
Water scarcity is a critical global issue impacting human life. Supply-side solutions alone do not meet the ever-increasing water demands. Economic assessment of water resources can reduce water sc...
- Published
- 2021
14. Assessment and prediction of band edge locations of nitrides using a self-consistent hybrid functional
- Author
-
Hyungjun Kim, Se-Jun Kim, Sébastien Lebègue, and Won June Kim
- Subjects
Materials science ,business.industry ,Band gap ,General Physics and Astronomy ,Ionic bonding ,Heterojunction ,Nitride ,Edge (geometry) ,Hybrid functional ,Photovoltaics ,Optoelectronics ,Density functional theory ,Physical and Theoretical Chemistry ,business - Abstract
Due to their optimal bandgap size and large defect tolerance, nitrides are becoming pivotal materials in several optoelectronic devices, photovoltaics, and photocatalysts. A computational method that can accurately predict their electronic structures is indispensable for exploring new nitride materials. However, the relatively small bandgap of nitrides, which stems from the subtle balance between ionic and covalent bond characteristics, makes conventional density functional theory challenging to achieve satisfactory accuracy. Here, we employed a self-consistent hybrid functional where the Hartree–Fock mixing parameter is self-consistently determined and thus the empiricism of the hybrid functional is effectively removed to calculate the bandgaps of various nitride compounds. By comparing the bandgaps from the self-consistent hybrid functional calculations with the available experimental and high-level GW calculation results, we found that the self-consistent hybrid functional can provide a computationally efficient approach for quantitative predictions of nitride electronic structures with an accuracy level comparable to the GW method. Additionally, we aligned the band edge positions of various nitride compounds using self-consistent hybrid functional calculations, providing material design principles for heterostructures of nitride-based optoelectronic devices. We anticipate the wide use of the self-consistent hybrid functional for accelerating explorations and predictions of new nitride-based functional materials in various photoactive applications.
- Published
- 2021
15. Atomic Layer Deposition of Titanium Silicate for Multi-Patterning Process
- Author
-
Sanghun Lee, Hyungjun Kim, Il Kwon Oh, Wontae Noh, and Seung Gi Seo
- Subjects
Materials science ,business.industry ,technology, industry, and agriculture ,chemistry.chemical_element ,Infrared spectroscopy ,Substrate (electronics) ,Silicate ,Characterization (materials science) ,chemistry.chemical_compound ,Atomic layer deposition ,Semiconductor ,chemistry ,Chemical engineering ,Ternary operation ,business ,Titanium - Abstract
We develop the atomic layer deposition (ALD) process of titanium silicate with halide-free precursor and evaluate film properties as a spacer for self-aligned double/quadruple patterning (SADP/SAQP). Growth characteristics are investigated depending on substrate temperature. Growth per cycle (GPC) at 100 °C is largely observed than the estimated value, while that as 200 °C shows an opposite trend. There have been reports on ALD ternary oxides, but different growth characteristics observed in this work have not been fully understood. In this work, the growth behavior of ALD titanium silicate are studied by correlating different characterization results, including infrared spectra, chemical compositions, and X-ray reflection spectra. Correlative results suggest that the surface density of hydroxyl group would be a key role for different growth characteristics of titanium silicates. Also, the feasibility of ALD titanium silicate as a spacer is evaluated, such as etch rates and deposited titanium silicates shows better quality than a conventional SiO 2 spacer. This study on ALD titanium silicate should significantly expand multi-patterning applications, especially in a semiconductor field.
- Published
- 2021
16. Appropriate follow-up period for odontogenic keratocyst: a retrospective study
- Author
-
In Ho Cha, Woong Nam, Hyungjun Kim, Jung Hwan Lim, and Hwi-Dong Jung
- Subjects
Recurrence of OKC ,medicine.medical_specialty ,RD1-811 ,Enucleation ,03 medical and health sciences ,0302 clinical medicine ,KCOT, Recurrence ,medicine ,OKC ,Keratocyst ,030223 otorhinolaryngology ,business.industry ,Research ,Incidence (epidemiology) ,RK1-715 ,Retrospective cohort study ,030206 dentistry ,Odontogenic kerotocyst ,Surgery ,Keratocystic odontogenic tumor ,Dentistry ,Maxilla ,Oral and maxillofacial surgery ,Keratocystic Odontogenic Tumor ,medicine.symptom ,business ,Cohort study - Abstract
Purpose The aim of this study was to conduct epidemiologic investigations on the pattern of the lesion and differences between treatment modalities in terms of recurrence by reviewing follow-up records to form a basis for planning patient follow-up visits. Materials and methods In this retrospective, single-center cohort study, 266 patients diagnosed with odontogenic keratocyst between 1993 and 2013 were included. Medical records and radiographic images were analyzed for age distribution, occurrence site and size, treatment modalities, and recurrence. Results The average age at first diagnosis was 33.1 years, and the male to female ratio was 1.33:1.00. The highest rate of incidence was in the third decade followed by the fourth, second, and fifth decades. The incidence in the maxilla was 34%, and 66% in the mandible. Mandibular ramus was most commonly involved. Lesions between 3 and 6 crowns were the most common, and the rate of recurrence increased with size. Enucleation after decompression had higher rate of recurrence (35.8%) than enucleation (27.1%), but there was no statistical significance. Conclusion The recurrence of odontogenic kerotocyst (OKC) was significantly associated with large size, multilocular form, and surgical procedure. A 10-year follow-up period is recommended to determine any recurrence of OKC.
- Published
- 2021
17. A systematic review and meta-analysis of regional risk factors for critical outcomes of COVID-19 during early phase of the pandemic
- Author
-
Jinwoo Lee, Hyunsook Hong, Jae-Joon Yim, Hyeontaek Hwang, and Hyungjun Kim
- Subjects
Male ,medicine.medical_specialty ,Asia ,Science ,Population ,Disease ,Anorexia ,030204 cardiovascular system & hematology ,Article ,03 medical and health sciences ,Medical research ,Sex Factors ,0302 clinical medicine ,Epidemiology ,Pandemic ,Humans ,Medicine ,030212 general & internal medicine ,Signs and symptoms ,education ,Pandemics ,education.field_of_study ,Multidisciplinary ,SARS-CoV-2 ,business.industry ,Mortality rate ,Age Factors ,COVID-19 ,Prognosis ,Europe ,Risk factors ,Outcomes research ,Meta-analysis ,North America ,Female ,medicine.symptom ,business ,Demography - Abstract
The mortality rates of COVID-19 vary across the globe. While some risk factors for poor prognosis of the disease are known, regional differences are suspected. We reviewed the risk factors for critical outcomes of COVID-19 according to the location of the infected patients, from various literature databases from January 1 through June 8, 2020. Candidate variables to predict the outcome included patient demographics, underlying medical conditions, symptoms, and laboratory findings. The risk factors in the overall population included sex, age, and all inspected underlying medical conditions. Symptoms of dyspnea, anorexia, dizziness, fatigue, and certain laboratory findings were also indicators of the critical outcome. Underlying respiratory disease was associated higher risk of the critical outcome in studies from Asia and Europe, but not North America. Underlying hepatic disease was associated with a higher risk of the critical outcome from Europe, but not from Asia and North America. Symptoms of vomiting, anorexia, dizziness, and fatigue were significantly associated with the critical outcome in studies from Asia, but not from Europe and North America. Hemoglobin and platelet count affected patients differently in Asia compared to those in Europe and North America. Such regional discrepancies should be considered when treating patients with COVID-19.
- Published
- 2021
18. Manufacture and Behaviors of Superconducting Busbar Joint for ITER Correction Coil Feeder
- Author
-
Liu Chen, Xiongyi Huang, Kun Lu, Hyungjun Kim, Jaromir Farek, Wen Xinjie, Kaizhong Ding, Chen-yu Gung, Erwu Niu, Liu Chenglian, Chunlong Zou, and Yury Ilin
- Subjects
Pressure drop ,Engineering ,Thermonuclear fusion ,Tokamak ,Busbar ,business.industry ,Mechanical engineering ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Electromagnetic coil ,law ,Soldering ,Joint (building) ,Electricity ,Electrical and Electronic Engineering ,business - Abstract
International Thermonuclear Experimental Reactor (ITER) is the largest global cooperation project, which will be built as the world's largest tokamak to explore the commercial production of fusion-based electricity. In order to connect the busbars electrically and hydraulically, the “shaking hands” twin-box type joint was designed and implemented for ITER project. Different from the conventional method, the indium bonding technology was developed instead of the Tin soldering method for the joint connection. In order to qualify for the ITER correction coil (CC) feeder joint structure and the manufacturing technology, Institute of Plasma Physics, Chinese Academy of Science (ASIPP) has launched the joint qualification on the manufacture process and the cryogenic performance. By means of the indium bonding, the joint resistance can be lower than 1 nΩ before and after the mechanical fatigue. This paper reports the structure and manufacturing process of CC feeder joint, describes the establishing of the testing setup, and finally discusses the cryogenic testing results. Besides the joint resistance, the pressure drop and the critical temperature are reported.
- Published
- 2019
19. Traffic Steering System with Dual Connectivity for Video Streaming Services
- Author
-
Park Gi Seok, Donghyun Kim, Ha Jaejun, Sang-Heon Shin, Hyunmin Noh, Hyungjun Kim, Jeung won Choi, and Song Hwangjun
- Subjects
business.industry ,Computer science ,Fountain code ,Steering system ,Video streaming ,DUAL (cognitive architecture) ,business ,Software-defined networking ,Computer hardware - Published
- 2019
20. Hydrogen barrier performance of sputtered La2O3 films for InGaZnO thin-film transistor
- Author
-
Chong Hwon Lee, Joon Young Yang, Sanghun Lee, Dong Wook Choi, Yujin Lee, Il Kwon Oh, Kim Ho-Jin, Hyungjun Kim, Woo Hee Kim, Choong-Keun Yoo, and Taewook Nam
- Subjects
Materials science ,Hydrogen ,business.industry ,020502 materials ,Mechanical Engineering ,chemistry.chemical_element ,02 engineering and technology ,Substrate (electronics) ,Partial pressure ,Amorphous solid ,0205 materials engineering ,chemistry ,Mechanics of Materials ,Thin-film transistor ,Sputtering ,Optoelectronics ,General Materials Science ,Thin film ,business ,Shallow donor - Abstract
We report the hydrogen barrier performance of sputtered La2O3 thin films for the device stability of amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistors (TFTs). Hydrogen acts as a shallow donor in a-IGZO films, which makes TFTs conductive, resulting in degradation of their on/off properties. Since hydrogen can be easily incorporated by external environments or post-processing, an appropriate hydrogen barrier is essential for enhancing device stability. La2O3, with its extreme electronegativity, can provide excellent hygroscopic characteristics. Because hydrogen exists in the form of –OH groups inside a-IGZO films, La2O3 is expected to be a promising barrier material for preventing hydrogen incorporation. Therefore, we investigate the growth characteristics of sputtered La2O3 thin films as hydrogen barrier layers, focusing on variations in growth rate, refractive index, and film stress, which depend on various process parameters, such as radio-frequency (RF) power, O2 partial pressure, and substrate temperature during reactive magnetron sputtering. The effects of these parameters on hydrogen barrier properties are systematically investigated and correlated with the microstructures of La2O3 films. The results demonstrate that La2O3 films grown with low RF power and low O2 partial pressure have an amorphous phase and provide excellent hydrogen barrier performance. We anticipate that these experimental results will help improve the environmental stability of a-IGZO TFTs.
- Published
- 2019
21. Light Emission Enhancement by Tuning the Structural Phase of APbBr3 (A = CH3NH3, Cs) Perovskites
- Author
-
L. Debbichi, Nam-Gyu Park, Y. Choi, Do-Kyoung Lee, Dongho Kim, and Hyungjun Kim
- Subjects
Structural phase ,Materials science ,business.industry ,Photovoltaic system ,Halide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Active layer ,law.invention ,law ,Optoelectronics ,General Materials Science ,Light emission ,Physical and Theoretical Chemistry ,0210 nano-technology ,business ,Light-emitting diode ,Diode ,Perovskite (structure) - Abstract
Lead halide perovskite (APbX3) has recently emerged as a promising active layer in light-emitting diodes (LEDs) as well as an absorber for photovoltaic devices. For better LED properties, it is imp...
- Published
- 2019
22. Safety Assessment Framework for Nuclear Power Plant Decommissioning Workers
- Author
-
Donghyun Lee, HyungJun Kim, Seung Jun Lee, Choong Wie Lee, and Hee Reyoung Kim
- Subjects
Risk analysis ,General Computer Science ,Hazard and operability study ,business.industry ,Computer science ,General Engineering ,safety assessment ,risk assessment ,Nuclear power ,Nuclear power plant ,Nuclear decommissioning ,Task (project management) ,law.invention ,Risk analysis (engineering) ,law ,Radiological weapon ,General Materials Science ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,business ,decommissioning worker ,lcsh:TK1-9971 ,Failure mode and effects analysis - Abstract
Considering that the nuclear power plants have a licensed lifetime, the need for research on decommissioning is increasing along with the number of aging plants globally. Unlike the dismantling of other buildings, the decommissioning of a nuclear power plant involves radiation risk, which necessitates a new systematic safety assessment to reduce this risk. This paper proposes a framework for the safety assessment of workers in nuclear power plant decommissioning. The first step of the process is accident identification, in which initiating events caused by mechanical failures or human errors are identified and categorized in accordance with their causes. The second step is frequency analysis, in which worker exposure in normal conditions is evaluated to derive the work time for each required task, and possible events that may happen during each task are derived through both a hazard and operability study and a failure mode and effect analysis. The third step, consequence analysis, models accident scenarios using the dose assessment program VISIPLAN, and evaluates worker exposure in those accident scenarios. The last step is risk analysis, where radiological risk is calculated quantitatively by the frequencies and exposure results of potential accidents. By performing the safety evaluations according to the proposed framework, the safety of workers in nuclear power plant decommissioning may be increased.
- Published
- 2019
23. Mapping Binary ResNets on Computing-In-Memory Hardware with Low-bit ADCs
- Author
-
Ji Hoon Park, Hyungjun Kim, Jae-Joon Kim, Hyunmyung Oh, and Yulhwa Kim
- Subjects
Memory management ,Artificial neural network ,Computer science ,business.industry ,Binary number ,Overhead (computing) ,Energy consumption ,Converters ,Quantization (image processing) ,business ,Energy (signal processing) ,Computer hardware - Abstract
Implementing binary neural networks (BNNs) on computing-in-memory (CIM) hardware has several attractive features such as small memory requirement and minimal overhead in peripheral circuits such as analog-to-digital converters (ADCs). On the other hand, one of the downsides of using BNNs is that it degrades the classification accuracy. Recently, ResNet-style BNNs are gaining popularity with higher accuracy than conventional BNNs. The accuracy improvement comes from the high-resolution skip connection which binary ResNets use to compensate the information loss caused by binarization. However, the high-resolution skip connection forces the CIM hardware to use high-bit ADCs again so that area and energy overhead becomes larger. In this paper, we demonstrate that binary ResNets can be also mapped on CIM with low-bit ADCs via aggressive partial sum quantization and input-splitting combined with retraining. As a result, the key advantages of BNN CIM such as small area and energy consumption can be preserved with higher accuracy.
- Published
- 2021
24. Numerical Analysis on the Radiation Efficiency of an Extruded Panel for the Railway Vehicle Using the Waveguide Finite Element and Boundary Element Method
- Author
-
David Thompson, Jungsoo Ryue, Hyungjun Kim, and Angela D. Müller
- Subjects
Vibration ,Materials science ,business.industry ,Numerical analysis ,Waveguide (acoustics) ,Point (geometry) ,Structural engineering ,Radiation ,business ,Boundary element method ,Finite element method ,Antenna efficiency - Abstract
Complex-shaped stiffened panels are widely used nowadays in many structures such as railway vehicles, ships and offshore structures, in order to make them lighter and stronger. Therefore, it is essential to investigate vibration and radiation of the complex shaped panels to predict the vibro-acoustic performance of the large structures. In this paper, a coupled waveguide finite element and boundary element method, which can be applied where the cross-sectional properties of the panels are constant in one direction, is applied to predict the radiation efficiency of the extruded panel. The dependence of the radiation efficiency on two different types of excitation positions is investigated; a point force in the middle of the strip or on an interior stiffener. Finally, numerical results are validated through the comparison with experiments carried out with a 1.5 m length extruded panel.
- Published
- 2021
25. Atomic and Molecular Unit Energy Conversion Catalysis of Carbon Dioxides in Value-Added Chemical Fuels
- Author
-
Hyung Mo Jeong, William A. GoddardIII, Jeung Ku Kang, Hyungjun Kim, and Kyung Min Choi
- Subjects
chemistry ,business.industry ,Global warming ,Value (economics) ,Environmental science ,chemistry.chemical_element ,Energy transformation ,Process engineering ,business ,Carbon ,Realization (systems) ,Catalysis ,Unit (housing) - Abstract
One of the major goals set by our humanity is to make breakthroughs in key technologies pertaining to energy, environment, and water. The main purpose of this chapter is to give an overview over sustainable CO2 conversion technologies that could be demonstrated from high-performance materials both design and also the realization, so that they could prevent simultaneously environmental problems such as global warming.
- Published
- 2021
26. Role of the RNF213 Variant in Vascular Outcomes in Patients With Intracranial Atherosclerosis
- Author
-
Eun-Hyeok Choi, Jae-Hwan Kim, Oh Young Bang, Jong Won Chung, Ye Sel Kim, Gyeong-Moon Kim, Woo-Keun Seo, and Hyungjun Kim
- Subjects
Male ,medicine.medical_specialty ,RNF213 variant ,Ubiquitin-Protein Ligases ,intracranial atherosclerosis ,Brief Communication ,Gastroenterology ,Polymorphism, Single Nucleotide ,Moyamoya disease ,Neuroimaging ,Recurrence ,Internal medicine ,Republic of Korea ,medicine ,Humans ,In patient ,Genetic Predisposition to Disease ,Prospective cohort study ,Adenosine Triphosphatases ,medicine.diagnostic_test ,business.industry ,Asia, Eastern ,Hazard ratio ,Magnetic resonance imaging ,Susceptibility allele ,Middle Aged ,medicine.disease ,Intracranial Arteriosclerosis ,Magnetic Resonance Imaging ,Plaque, Atherosclerotic ,Stroke ,Mutation ,cardiovascular system ,Cerebrovascular Disease/Stroke ,Female ,Intracranial Atherosclerosis ,Cardiology and Cardiovascular Medicine ,business ,Moyamoya - Abstract
Background The RNF213 ( ring finger protein 213 gene) variant R4810K is a susceptibility allele not only for Moyamoya disease (MMD) but also for intracranial atherosclerosis (ICAS) in East Asian populations. We hypothesized that this variant would affect the distribution of ICAS and recurrence of cerebrovascular events. Methods and Results We conducted a prospective study of patients with ICAS and MMD using high‐resolution magnetic resonance imaging and RNF213 R4810K genotyping. Patients were included in the ICAS group when relevant plaques existed on high‐resolution magnetic resonance imagingand in the MMD group when they carried the variant and high‐resolution magnetic resonance imaging showed no plaques but characteristic features of MMD. We compared clinical and neuroimaging features of patients with ICAS‐ RNF213 + with patients with ICAS‐ RNF213 − and of patients with MMD. Of 477 patients, 238 patients were in the ICAS group and 239 were in the MMD group. Among patients with ICAS, 79 patients (33.2%) were in the ICAS‐ RNF213 + group and 159 (66.8%) in the ICAS‐ RNF213 − group. Tandem lesions were significantly more common in the ICAS‐ RNF213+ group than in the ICAS‐ RNF213 − group (40.3% versus 72.2%, P RNF213+ and MMD groups. The presence of the R4810K variant (hazard ratio [HR], 3.203; 95% CI, 1.149–9.459; P =0.026) and tandem lesions (≥3) (HR, 8.315; 95% CI, 1.930–39.607; P =0.005) were independently associated with recurrent cerebrovascular events. Conclusions Patients with ICAS carrying the RNF213 R4810K variant showed clinical and imaging features distinct from patients with ICAS without the variant, suggesting that the R4810K variant plays a role in intracranial atherosclerosis in East Asian patients.
- Published
- 2020
27. High-performance p-channel transistors with transparent Zn doped-CuI
- Author
-
Se-Jun Kim, Hyungjun Kim, Won-Tae Park, Yong-Young Noh, Myung-Gil Kim, Huihui Zhu, and Ao Liu
- Subjects
0301 basic medicine ,Electron mobility ,Materials science ,Science ,General Physics and Astronomy ,02 engineering and technology ,Integrated circuit ,Article ,General Biochemistry, Genetics and Molecular Biology ,law.invention ,03 medical and health sciences ,law ,Hardware_INTEGRATEDCIRCUITS ,Electronic devices ,Electronics ,lcsh:Science ,Spin coating ,Multidisciplinary ,business.industry ,Transistor ,Doping ,General Chemistry ,021001 nanoscience & nanotechnology ,Electrical and electronic engineering ,030104 developmental biology ,Semiconductor ,Thin-film transistor ,Optoelectronics ,lcsh:Q ,0210 nano-technology ,business ,Hardware_LOGICDESIGN - Abstract
‘Ideal’ transparent p-type semiconductors are required for the integration of high-performance thin-film transistors (TFTs) and circuits. Although CuI has recently attracted attention owing to its excellent opto-electrical properties, solution processability, and low-temperature synthesis, the uncontrolled copper vacancy generation and subsequent excessive hole doping hinder its use as a semiconductor material in TFT devices. In this study, we propose a doping approach through soft chemical solution process and transparent p-type Zn-doped CuI semiconductor for high-performance TFTs and circuits. The optimised TFTs annealed at 80 °C exhibit a high hole mobility of over 5 cm2 V−1 s−1 and high on/off current ratio of ~107 with good operational stability and reproducibility. The CuI:Zn semiconductors show intrinsic advantages for next-generation TFT applications and wider applications in optoelectronics and energy conversion/storage devices. This study paves the way for the realisation of transparent, flexible, and large-area integrated circuits combined with n-type metal-oxide semiconductor., Designing efficient thin-film transistors and circuits based on transparent p-type semiconductors remains a challenge. Here, the authors propose a solution-based doping approach to realize high performance transparent inorganic p-type semiconductors (Zn-doped CuI) by spin coating at 80 C with good operational stability.
- Published
- 2020
28. Impact of long-term exposure to ambient air pollution on the incidence of chronic obstructive pulmonary disease: A systematic review and meta-analysis
- Author
-
Hyungjun Kim, Chang Hoon Lee, Jimyung Park, Chang-Hyun Lee, and Hyun Woo Lee
- Subjects
medicine.medical_specialty ,Nitrogen Dioxide ,Air pollution ,Pulmonary disease ,010501 environmental sciences ,Cochrane Library ,medicine.disease_cause ,complex mixtures ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,Pulmonary Disease, Chronic Obstructive ,0302 clinical medicine ,Internal medicine ,Air Pollution ,medicine ,Humans ,030212 general & internal medicine ,Prospective Studies ,0105 earth and related environmental sciences ,General Environmental Science ,COPD ,Air Pollutants ,Ambient air pollution ,business.industry ,Incidence (epidemiology) ,Incidence ,Environmental Exposure ,medicine.disease ,respiratory tract diseases ,Meta-analysis ,Particulate Matter ,business ,Cohort study - Abstract
Background: It is well known that air pollution causes respiratory morbidity and mortality by inducing airway inflammation. However, whether long-term exposure to air pollution is associated with increased incidence of chronic obstructive pulmonary disease (COPD) is controversial. Methods: We conducted a systematic review and meta-analysis with a random-effects model to calculate the pooled risk estimates of COPD development per 10 μg/m3 increase in individual air pollutants. PubMed, Embase, and Cochrane Library were searched from the date of their inception to August 2019 to identify long-term (at least three years of observation) prospective longitudinal studies that reported the risk of COPD development due to exposure to air pollutants. The air pollutants studied included particulate matter (PM2.5 and PM10) and nitrogen dioxide (NO2). Results: Of the 436 studies identified, seven met our eligibility criteria. Among the seven studies, six, three, and five had data on PM2.5, PM10, and NO2, respectively. The meta-analysis results showed that a 10 μg/m3 increase in PM2.5 is associated with increased incidence of COPD (pooled HR 1.18, 95% CI 1.13–1.23). We also noted that a 10 μg/m3 increase in NO2 is marginally associated with increased incidence of COPD (pooled HR 1.07, 95% CI 1.00–1.16). PM10 seems to have no significant impact on the incidence of COPD (pooled HR 0.95, 95% CI 0.83–1.08), although the number of studies was too small. Meta-regression analysis found no significant effect modifiers. Conclusions: Long-term exposure to PM2.5 and NO2 can be associated with increased incidence of COPD.
- Published
- 2020
29. HESS Opinions: Improving the evaluation of groundwater representation in continental to global scale models
- Author
-
Tom Gleeson, Thorsten Wagener, Petra Döll, Samuel C. Zipper, Charles West, Yoshihide Wada, Richard Taylor, Bridget Scanlon, Rafael Rosolem, Shams Rahman, Nurudeen Oshinlaja, Reed Maxwell, Min-Hui Lo, Hyungjun Kim, Mary Hill, Andreas Hartmann, Graham Fogg, James S. Famiglietti, Agnès Ducharne, Inge de Graaf, Mark Cuthbert, Laura Condon, Etienne Bresciani, and Marc F. P. Bierkens
- Subjects
Commensurability (philosophy of science) ,business.industry ,Computer science ,0208 environmental biotechnology ,Environmental resource management ,Expert elicitation ,02 engineering and technology ,Field (geography) ,020801 environmental engineering ,Earth system science ,Sustainability ,business ,Groundwater model ,Representation (mathematics) ,Groundwater - Abstract
Continental- to global-scale hydrologic and land surface models increasingly include representations of the groundwater system, driven by crucial Earth science and sustainability problems. These models are essential for examining, communicating, and understanding the dynamic interactions between the Earth System above and below the land surface as well as the opportunities and limits of groundwater resources. A key question for this nascent and rapidly developing field is how to evaluate the realism and performance of such large-scale groundwater models given limitations in data availability and commensurability. Our objective is to provide clear recommendations for improving the evaluation of groundwater representation in continental- to global-scale models. We identify three evaluation approaches, including comparing model outputs with available observations of groundwater levels or other state or flux variables (observation-based evaluation); comparing several models with each other with or without reference to actual observations (model-based evaluation); and comparing model behavior with expert expectations of hydrologic behaviors that we expect to see in particular regions or at particular times (expert-based evaluation). Based on current and evolving practices in model evaluation as well as innovations in observations, machine learning and expert elicitation, we argue that combining observation-, model-, and expert-based model evaluation approaches may significantly improve the realism of groundwater representation in large-scale models, and thus our quantification, understanding, and prediction of crucial Earth science and sustainability problems. We encourage greater community-level communication and cooperation on these challenges, including among global hydrology and land surface modelers, local to regional hydrogeologists, and hydrologists focused on model development and evaluation.
- Published
- 2020
30. Algorithm/Hardware Co-Design for In-Memory Neural Network Computing with Minimal Peripheral Circuit Overhead
- Author
-
Hyungjun Kim, Yulhwa Kim, Jae-Joon Kim, and Sungju Ryu
- Subjects
Artificial neural network ,Computer science ,Sense amplifier ,business.industry ,Path (graph theory) ,Line driver ,Overhead (computing) ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,business ,Word (computer architecture) ,Energy (signal processing) ,Computer hardware ,Electronic circuit - Abstract
We propose an in-memory neural network accelerator architecture called MOSAIC which uses minimal form of peripheral circuits; 1-bit word line driver to replace DAC and 1-bit sense amplifier to replace ADC. To map multi-bit neural networks on MOSAIC architecture which has 1-bit precision peripheral circuits, we also propose a bit-splitting method to approximate the original network by separating each bit path of the multi-bit network so that each bit path can propagate independently throughout the network. Thanks to the minimal form of peripheral circuits, MOSAIC can achieve an order of magnitude higher energy and area efficiency than previous in-memory neural network accelerators.
- Published
- 2020
31. Reduced tactile acuity in chronic low back pain is linked with structural neuroplasticity in primary somatosensory cortex and is modulated by acupuncture therapy
- Author
-
Ted J. Kaptchuk, Jeungchan Lee, Robert R. Edwards, Jieun Kim, Ajay D. Wasan, Vitaly Napadow, Suk-Tak Chan, Randy L. Gollub, Kathryn Walker, Bruce R. Rosen, Hyungjun Kim, Jessica Gerber, Marco L. Loggia, Jian Kong, Ishtiaq Mawla, and Ana Ortiz
- Subjects
Male ,Acupuncture Therapy ,Somatosensory system ,0302 clinical medicine ,Discrimination, Psychological ,Medicine ,Single-Blind Method ,Longitudinal Studies ,Gray Matter ,Tactile acuity ,Neuronal Plasticity ,Two-point discrimination threshold ,05 social sciences ,Chronic pain ,Middle Aged ,Low back pain ,Diffusion Tensor Imaging ,Treatment Outcome ,Neurology ,Touch Perception ,Sensory Thresholds ,Agnosia ,Body region ,Female ,medicine.symptom ,Adult ,medicine.medical_specialty ,Adolescent ,Cognitive Neuroscience ,Primary sensory cortex ,050105 experimental psychology ,Article ,lcsh:RC321-571 ,03 medical and health sciences ,Young Adult ,Physical medicine and rehabilitation ,Neuroimaging ,Fractional anisotropy ,Neuroplasticity ,Acupuncture ,Humans ,0501 psychology and cognitive sciences ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,business.industry ,Somatosensory Cortex ,medicine.disease ,Anisotropy ,business ,human activities ,Low Back Pain ,030217 neurology & neurosurgery ,Psychomotor Performance - Abstract
Prior studies have shown that patients suffering from chronic Low Back Pain (cLBP) have impaired somatosensory processing including reduced tactile acuity, i.e. reduced ability to resolve fine spatial details with the perception of touch. The central mechanism(s) underlying reduced tactile acuity are unknown but may include changes in specific brain circuitries (e.g. neuroplasticity in the primary somatosensory cortex, S1). Furthermore, little is known about the linkage between changes in tactile acuity and the amelioration of cLBP by somatically-directed therapeutic interventions, such as acupuncture. In this longitudinal neuroimaging study, we evaluated healthy control adults (HC, N = 50) and a large sample of cLBP patients (N = 102) with structural brain imaging (T1-weighted MRI for Voxel-Based Morphometry, VBM; Diffusion Tensor Imaging, DTI) and tactile acuity testing using two-point discrimination threshold (2PDT) over the lower back (site of pain) and finger (control) locations. Patients were evaluated at baseline and following a 4-week course of acupuncture, with patients randomized to either verum acupuncture, two different forms of sham acupuncture (designed with or without somatosensory afference), or no-intervention usual care control. At baseline, cLBP patients demonstrated reduced acuity (greater 2PDT, P = 0.01) over the low back, but not finger (P = 0.29) locations compared to HC, suggesting that chronic pain affects tactile acuity specifically at body regions encoding the experience of clinical pain. At baseline, Gray Matter Volume (GMV) was elevated and Fractional Anisotropy (FA) was reduced, respectively, in the S1-back region of cLBP patients compared to controls (P
- Published
- 2020
32. Water Governance Contribution to Water and Sanitation Access Equality in Developing Countries
- Author
-
Tidar Bayu, Hyungjun Kim, and Taikan Oki
- Subjects
Inequality ,Sanitation ,Corporate governance ,media_common.quotation_subject ,Development economics ,Developing country ,Business ,Water Science and Technology ,media_common - Published
- 2020
33. Abstract WP271: The Role of Ring Finger Protein213 Variant in Patients With Intracranial Atherosclerotic Disease
- Author
-
Mee So Lee, Gyeong-Moon Kim, Ingyeong Kim, Jae-Hwan Kim, Hyungjun Kim, Inyoung Baek, Ye Sel Kim, and Oh Young Bang
- Subjects
Advanced and Specialized Nursing ,medicine.medical_specialty ,education.field_of_study ,business.industry ,Population ,Genetic variants ,Atherosclerotic disease ,medicine.disease ,medicine.anatomical_structure ,Internal medicine ,Cardiology ,Ring finger ,Medicine ,In patient ,Neurology (clinical) ,Cardiology and Cardiovascular Medicine ,business ,education ,Stroke - Abstract
Introduction: The Ring Finger Protein213 ( RNF213 ) gene variant is a relatively common variant in general population of East Asian countries (0.43 to 1.8%). Recently, RNF213 is reportedly a susceptibility gene not only for moyamoya disease (MMD) but also for intracranial atherosclerosis (ICAS) in this population. However, the role of this genetic factor in patients with ICAS is unknown. We hypothesized that this variant is involved in the pathogenesis of ICAS. Methods: We conducted a prospective study of patients with ICAS and MMD using high-resolution MRI (HR-MRI) and RNF213 (p.Arg4810Lys variant) gene studies. Patients were classified into intracranial atherosclerosis (ICAS) when relevant plaques existed on HR-MRI and moyamoya disease (MMD) when patients had RNF213 variant and HR-MRI showed no plaque but characteristic features of MMD (negative remodeling and basal collaterals). We compared clinical and neuroimaging features between (a) the RNF213 - ICAS, (b) the RNF213 + ICAS, and (c) MMD group. Results: Among 178 patients analyzed, 79 were the RNF213 - ICAS, 37 the RNF213 variant+ ICAS, and 62 the MMD group. Vascular risk factors were more frequently observed in ICAS than MMD patients, but there was no difference between RNF213 - ICAS and the RNF213 variant+ ICAS. Moreover, the site of occlusive disease was different between ICAS and MMD patients, but not between RNF213 - ICAS and the RNF213 variant+ ICAS. It was more distally located in RNF213 variant+ ICAS than in MMD (p=0.012). Compared to RNF213 - ICAS patients, tandem lesions were significantly more common in RNF213 + ICAS (24.1% vs. 67.6%, p Conclusions: Patients with ICAS and the RNF213 variant showed distinct clinical and imaging features from MMD patients. A high frequency of tandem lesions in RNF213 + ICAS suggest that this variant may have synergic effects in atherosclerosis which should be tested in a larger cohort.
- Published
- 2020
34. Abstract TP475: Effect of Udenafil, a Phosphodiesterase-5 Inhibitor, on Angiogenesis in a Cav-1 Deficient Moyamoya Disease Model
- Author
-
Mee So Lee, Inyoung Baek, Gyeong-Moon Kim, Jae-Hwan Kim, Ye Sel Kim, Oh Young Bang, Hyungjun Kim, and Ingyeong Kim
- Subjects
Advanced and Specialized Nursing ,Udenafil ,medicine.drug_mechanism_of_action ,Angiogenesis ,business.industry ,Pharmacology ,medicine.disease ,cardiovascular system ,medicine ,Neurology (clinical) ,Moyamoya disease ,Cardiology and Cardiovascular Medicine ,business ,Phosphodiesterase 5 inhibitor ,medicine.drug - Abstract
Background: Although pathogenic mechanisms of moyamoya disease remain unknown, recent studies suggest that it is a caveolae disease. This study evaluated the effect of udenafil, a phosphodiesterase-5 inhibitor, on vessel maturation in in vitro and in vivo moyamoya disease models. Methods: Angiogenesis and vessel maturation were assessed in in vitro models, caveolin-1 (Cav-1) knockdown human umbilical vessel endothelial cells (HUVECs) and coronary artery smooth muscle cells (CASMCs), and in in vivo model of bilateral internal carotid artery occlusion (bICAo). Udenafil was administered (1,3,10 and 30 μM) in cell culture conditions, and functional studies (migration and tube formation assay) were performed and vessel maturation factors and cyclic guanosine monophosphate (cGMP) accumulation were measured. Udenafil (3 and 10 mg/kg) was orally administered once daily for 4 weeks in bICAo rat model, and histological analysis for angiogenesis and vessel maturation was performed. Results: Udenafil increased vessel formation in both Cav-1 knockdown HUVEC and bICAo models without increased migration/proliferation of HUVECs and CASMCs. Udenafil increased CD31+ vessel density and NG2/Col4+ mural cell density in bICAo models. Cav-1 knockdown inhibited accumulation of cGMP, and udenafil treatment restored cGMP levels in Cav-1 knockdown HUVEC models. Vessel maturation factors (angiopoietin-1 and platelet-derived growth factor receptor-β) and angiogenic factors (endothelial nitric oxide synthase) were increased after treatment with udenafil in vitro . Conclusion: Our results indicate that udenafil reversed cellular levels of cGMP related to Cav-1 deficiency and induced angiogenesis and vessel maturation. Further studies are warranted to confirm the therapeutic effects of this strategy in moyamoya disease.
- Published
- 2020
35. Abstract WP270: Etiopathologies of Symptomatic and Asymptomatic Intracranial Large Arterial Disease: The Results of HR-MRI and Genetic Studies
- Author
-
Oh Young Bang, Inyoung Baek, Jae-Hwan Kim, Hyungjun Kim, Ingyeong Kim, Mee So Lee, Gyeong-Moon Kim, and Ye Sel Kim
- Subjects
Advanced and Specialized Nursing ,medicine.medical_specialty ,Arterial disease ,business.industry ,medicine ,Neurology (clinical) ,Radiology ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Asymptomatic - Abstract
Introduction: Intracranial large arterial disease (ILAD) is common, especially in Asians. We compared clinical, genetic, and imaging features between symptomatic and asymptomatic ILAD. Methods: We conducted a prospective study of patients with acute symptomatic ILAD and subjects with asymptomatic ILAD diagnosed during medical checkups. Patients who had steno-occlusive lesions on the middle cerebral artery and/or distal internal carotid artery underwent high-resolution MRI (HR-MRI) and RNF213 (p.Arg4810Lys variant) gene studies. We excluded patients who had proximal embolic sources in ipsilateral carotid and heart. A presumptive etiology of ILAD was made based on HR-MRI and RNF213 gene studies. Patients were classified into intracranial atherosclerosis (ICAS) when relevant plaques existed on HR-MRI; moyamoya disease (MMD) when patients had RNF213 variant and HR-MRI showed no plaque but characteristic features of MMD (negative remodeling and basal collaterals); and intracranial arterial dissection (ICAD) when pathognomic features (intimal flap/double lumen or mural hematoma) exist on HR-MRI. Results: Among 224 patients analyzed, 124 were symptomatic and 100 were asymptomatic. ICAS-type was more common in symptomatic ILAD than in asymptomatic ILAD (61.4% vs. 45.0%, p=0.009). The RNF213 variant was observed in one third of ICAS-type ILAD (37.0% in asymptomatic and 38.6% in symptomatic). Similarly, the proportion of MMD-type was similar between asymptomatic (33, 21.3%) and symptomatic (32, 19.0%) ILAD. Multivariate testing showed that symptomatic ILAD was associated with the presence of intracranial plaque on HR-MRI, regardless of the presence of the RNF213 variant, site of ILAD, and number of tandem stenosis. Conclusions: While various etiopathologies can cause ILAD, ICAS is an important pathology of symptomatic ILAD and should be target for medical management.
- Published
- 2020
36. Abstract TP84: Prognostic Factor of Intracranial Vertebral Artery Dissection: High Resolution Vessel Wall Magnetic Resonance Imaging Study
- Author
-
Woo-Keun Seo, Oh Young Bang, Jae-Hwan Kim, Ye Sel Kim, Gyeong-Moon Kim, and Hyungjun Kim
- Subjects
Advanced and Specialized Nursing ,Prognostic factor ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Vertebral artery dissection ,High resolution ,Magnetic resonance imaging ,medicine.disease ,Internal medicine ,parasitic diseases ,Ischemic stroke ,medicine ,Cardiology ,cardiovascular diseases ,Neurology (clinical) ,Cardiology and Cardiovascular Medicine ,business ,Stroke - Abstract
Background: Vertebral artery dissection (VAD) is well recognized cause of stroke in young and middle aged individuals. But, prognostic factor of posterior circulation ischemic stroke or transient ischemic attack (TIA) caused by intracranial VAD has been rarely discussed. Our aim was to evaluate the predictors of poor outcomes in posterior circulation ischemic stroke caused by intracranial VAD. Methods: We retrospectively reviewed patients with posterior circulation ischemic stroke or TIA caused by intracranial VAD using high-resolution vessel wall MRI who were recruited from Samsung Medical Center Stroke Registry (between January 1, 2011 and April 30, 2019). Poor outcomes were defined as a 3-months modified Rankin scale (mRS) score ≥ 2. Results: We registered 96 patients (74 males; mean age, 58.9±14.2 years) with acute posterior circulation ischemic stroke or TIA caused by intracranial VAD. Trauma history associated with VAD was presented in 23 (24%) of patients. Headache and neck pain around neurological symptom onset were presented in 41 (42.7%) and 19 (19.8%) of patients, respectively. Dissecting aneurysm, bilateral vertebral artery involvement, basilar artery involvement and wall hematoma with dissection were presented in 26 (27.1%), 26 (27.1%), 12 (12.5%) and 66 (68.8%) of patients, respectively. Of the 96 VADs, 26 (27.1%) presented with focal stenosis, 21 (21.9%) with multifocal stenosis, and 57 (59.4%) with occlusion. Lateral medulla involvement and multiple territory involvement were presented in 35 (36.5%) and 31 (32.3%) of patients. Recurrence rate of ischemic stroke or TIA within 90 days of symptom onset was 6.25%. Twenty-nine patients (30.2%) had poor outcomes at 3 months. Lateral medulla involvement was an independent predictor for poor outcome (odds ratio=3.293, 95% confidence interval=1.301-8.333, p=0.012). Conclusion: Posterior circulation ischemic stroke or TIA caused by intracranial VAD is associated with relatively benign clinical course. But the presence of lateral medulla involvement is independent predictor for poor outcome. Patients presenting lateral medullary infarction caused by intracranial VAD should be monitored closely.
- Published
- 2020
37. Improving Accuracy of Binary Neural Networks using Unbalanced Activation Distribution
- Author
-
Jihoon Park, Hyungjun Kim, Changhun Lee, and Jae-Joon Kim
- Subjects
FOS: Computer and information sciences ,Computer Science - Machine Learning ,Artificial neural network ,business.industry ,Computer science ,Deep learning ,Computer Vision and Pattern Recognition (cs.CV) ,Computer Science - Computer Vision and Pattern Recognition ,Binary number ,Contrast (statistics) ,Binary neural network ,Machine Learning (cs.LG) ,Distribution (mathematics) ,Artificial intelligence ,business ,Algorithm - Abstract
Binarization of neural network models is considered as one of the promising methods to deploy deep neural network models on resource-constrained environments such as mobile devices. However, Binary Neural Networks (BNNs) tend to suffer from severe accuracy degradation compared to the full-precision counterpart model. Several techniques were proposed to improve the accuracy of BNNs. One of the approaches is to balance the distribution of binary activations so that the amount of information in the binary activations becomes maximum. Based on extensive analysis, in stark contrast to previous work, we argue that unbalanced activation distribution can actually improve the accuracy of BNNs. We also show that adjusting the threshold values of binary activation functions results in the unbalanced distribution of the binary activation, which increases the accuracy of BNN models. Experimental results show that the accuracy of previous BNN models (e.g. XNOR-Net and Bi-Real-Net) can be improved by simply shifting the threshold values of binary activation functions without requiring any other modification., Comment: CVPR 2021, 10 pages, 10 figures
- Published
- 2020
- Full Text
- View/download PDF
38. Immunopathogenesis of ANCA-Associated Vasculitis
- Author
-
Yunryoung Cho, Minha Hwang, Junhye Park, Hyo Jeong Lee, Kang Hyun Kim, Lee Smith, Ji Han Lee, Jae Il Shin, Han Li, Sun Wook Jung, Junseong Park, Hyungjun Kim, Do Young Kim, Andreas Kronbichler, Haejune Sung, Sara Denicolò, Hojune Lee, Geonjae Cho, Dong-Il Kim, Daeun Choi, Philipp Gauckler, Keum Hwa Lee, Dongkyu Lee, Hyung Tae Kim, Jaehyuk Hwang, Ai Koyanagi, Injae Hwang, Sohee Kim, Changjun Lee, Min Je Choi, Louis Jacob, Kalthoum Tizaoui, Donghyun Ahn, Innsbruck Medical University [Austria] (IMU), Yonsei University, Faculté de médecine - Faculty of Medicine [Sfax, Tunisie] (FMS), Université de Sfax - University of Sfax, University of Florida [Gainesville] (UF), Anglia Ruskin University (ARU), Centro de Investigación Biomédica en Red Salud Mental [Madrid] (CIBER-SAM), ICREA Infection Biology Laboratory (Department of Experimental and Health Sciences), Universitat Pompeu Fabra [Barcelona] (UPF), Université de Versailles Saint-Quentin-en-Yvelines - UFR Sciences de la santé Simone Veil (UVSQ Santé), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
- Subjects
0301 basic medicine ,[SDV]Life Sciences [q-bio] ,Microscopic Polyangiitis ,Review ,Churg-Strauss Syndrome ,urologic and male genital diseases ,lcsh:Chemistry ,0302 clinical medicine ,Proteinase 3 ,immune system diseases ,Eosinophilic ,skin and connective tissue diseases ,lcsh:QH301-705.5 ,Spectroscopy ,biology ,treatment ,ANCA ,pathogenesis ,General Medicine ,Prognosis ,3. Good health ,Computer Science Applications ,Myeloperoxidase ,Biomarker (medicine) ,biomarker ,Microscopic polyangiitis ,Granulomatosis with polyangiitis ,Vasculitis ,phenotype ,Myeloblastin ,Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis ,Serogroup ,Catalysis ,Antibodies, Antineutrophil Cytoplasmic ,Inorganic Chemistry ,03 medical and health sciences ,medicine ,Humans ,cardiovascular diseases ,Physical and Theoretical Chemistry ,Molecular Biology ,Peroxidase ,030203 arthritis & rheumatology ,business.industry ,Organic Chemistry ,Granulomatosis with Polyangiitis ,medicine.disease ,respiratory tract diseases ,030104 developmental biology ,lcsh:Biology (General) ,lcsh:QD1-999 ,Immunology ,biology.protein ,Personalized medicine ,business ,Biomarkers - Abstract
International audience; Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is an autoimmune disorder which affects small-and, to a lesser degree, medium-sized vessels. ANCA-associated vasculitis encompasses three disease phenotypes: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). This classification is largely based on clinical presentations and has several limitations. Recent research provided evidence that genetic background, risk of relapse, prognosis, and co-morbidities are more closely related to the ANCA serotype, proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA, compared to the disease phenotypes GPA or MPA. This finding has been extended to the investigation of biomarkers predicting disease activity, which again more closely relate to the ANCA serotype. Discoveries related to the immunopathogenesis translated into clinical practice as targeted therapies are on the rise. This review will summarize the current understanding of the immunopathogenesis of ANCA-associated vasculitis and the interplay between ANCA serotype and proposed disease biomarkers and illustrate how the extending knowledge of the immunopathogenesis will likely translate into development of a personalized medicine approach in the management of ANCA-associated vasculitis.
- Published
- 2020
39. High-Performance Gas Sensor Using a Large-Area WS2xSe2–2x Alloy for Low-Power Operation Wearable Applications
- Author
-
Jeong Gyu Song, Kyunam Park, Jusang Park, Kyung Yong Ko, Whang Je Woo, Sangyoon Lee, Zonghoon Lee, Dong-Hyun Kim, Hyungjun Kim, Jung Hwa Kim, and Youngjun Kim
- Subjects
Materials science ,business.industry ,Alloy ,Wearable computer ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Power (physics) ,engineering ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business - Abstract
Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have attracted considerable attention as promising building blocks for a new generation of gas-sensing devices because of their excellent electrical properties, superior response, flexibility, and low-power consumption. Owing to their large surface-to-volume ratio, various 2D TMDCs, such as MoS2, MoSe2, WS2, and WSe2, have exhibited excellent gas-sensing characteristics. However, exploration toward the enhancement of TMDC gas-sensing performance has not yet been intensively addressed. Here, we synthesized large-area uniform WS2 xSe2-2 x alloys for room-temperature gas sensors. As-synthesized WS2 xSe2-2 x alloys exhibit an elaborative composition control owing to their thermodynamically stable sulfurization process. Further, utilizing uniform WS2 xSe2-2 x alloys over a large area, we demonstrated improved NO2-sensing performance compared to WSe2 on the basis of an electronic sensitization mechanism. The WS0.96Se1.04 alloy gas sensor exhibits 2.4 times enhanced response for NO2 exposure. Further, we demonstrated a low-power wearable NO2-detecting wristband that operates at room temperature. Our results show that the proposed method is a promising strategy to improve 2D TMDC gas sensors and has a potential for applications in advanced gas-sensing devices.
- Published
- 2018
40. A Knowledge-Based Real-Time Vision System for Monitoring the Inside of a Fluid Bed Heat Exchanger Chamber
- Author
-
HyungJun Kim
- Subjects
Computer Networks and Communications ,business.industry ,Machine vision ,Flux ,Thermal power station ,Mechanical engineering ,02 engineering and technology ,Computer Graphics and Computer-Aided Design ,GeneralLiterature_MISCELLANEOUS ,Knowledge-based systems ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Artificial Intelligence ,Fluidized bed ,Heat exchanger ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,020201 artificial intelligence & image processing ,Coal ,Real time vision ,business ,Software - Abstract
In this paper, we present a vision system with a special camera for knowledge-based real-time monitoring of the inside of a fluid bed heat exchanger (FBHE) chamber in a thermal power plant. With the proposed system, it is possible to monitor the internal flux condition and analyze the inner temperature of a chamber. Due to the fact that the mixture of coal and sand inside a chamber flows by very quickly, there is an immense amount of smoke and dust, which make it difficult to capture images and analyze an existing system. An adaptive average method is proposed here to observe the background internal environment of an FBHE chamber. The experimental results show that real-time monitoring is possible, even under hot and dusty conditions. Preliminary experimental results confirm expectations about the possibility and effectiveness of the developed device for commercialized real-time monitoring systems. They demonstrate that a single camera with embedded image processing software can concurrently analyze the degree of fluidization of a mixture and the temperature of the chamber inside, even in extremely harsh and hazardous conditions. We aim to eventually develop an image analysis system that combines image processing and knowledge engineering techniques.
- Published
- 2018
41. High-Performance Flexible ZnO Nanorod UV/Gas Dual Sensors Using Ag Nanoparticle Templates
- Author
-
Do Kyun Kwon, Hyungjun Kim, Jae Min Myoung, Yoann Porte, and Kyung Yong Ko
- Subjects
Materials science ,business.industry ,Schottky barrier ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,medicine.disease_cause ,01 natural sciences ,0104 chemical sciences ,Electrode ,medicine ,Optoelectronics ,General Materials Science ,Nanorod ,Surface plasmon resonance ,Thin film ,0210 nano-technology ,business ,Solution process ,Ultraviolet - Abstract
Flexible zinc oxide (ZnO) nanorod (NR) ultraviolet (UV)/gas dual sensors using silver (Ag) nanoparticle (NP) templates were successfully fabricated on a polyimide substrate with nickel electrodes. Arrays of Ag NPs were used as a template for the growth of ZnO NRs, which could enhance the flexibility and the sensing properties of the devices through the localized surface plasmon resonance (LSPR) effect. The Ag NPs were fabricated by the rapid thermal annealing process of Ag thin films, and ZnO NRs were grown on Ag NPs to maximize the surface area and form networks with rod-to-rod contacts. Because of the LSPR effect by Ag NPs, the UV photoresponse of the ZnO NRs was amplified and the depletion region of ZnO NRs was formed quickly because of the Schottky contact with the Ag NPs. As a consequence, ZnO NR UV/gas dual sensors grown on the Ag NP template with a diameter of 28 nm exhibited the outstanding UV-sensing characteristics with a UV on–off ratio of 3628 and a rising time (tr) and a decay time (td) of 3....
- Published
- 2018
42. Warm Season Satellite Precipitation Biases for Different Cloud Types Over Western North Pacific
- Author
-
Hyungjun Kim and Nobuyuki Utsumi
- Subjects
Convection ,010504 meteorology & atmospheric sciences ,business.industry ,0208 environmental biotechnology ,Cloud computing ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,020801 environmental engineering ,law.invention ,Microwave imaging ,law ,Climatology ,Environmental science ,Satellite ,Precipitation ,Electrical and Electronic Engineering ,Radar ,business ,Global Precipitation Measurement ,Microwave ,0105 earth and related environmental sciences - Abstract
Two along-track (level 2) satellite precipitation retrievals by the Global Precipitation Measurement (GPM) Microwave Imager (GMI) and the Dual Frequency Precipitation Radar Ku-band (DPR-Ku) and two multisatellite precipitation products, global satellite mapping of precipitation (GSMaP) and Integrated Multisatellite Retrievals for GPM (IMERG), are intercompared for different cloud types during warm season over the western North Pacific region. It is found that the biases of the precipitation measurements are systematically associated with cloud types. The best agreements of passive microwave (PMW) products and infrared-based (IR) products with satellite radar-based estimates are found for a relatively weak precipitation range for mid-low clouds (except over land) and high clouds, while similar agreement is found for heavier precipitation range for deep convection regardless of surface type. Precipitation from mid-low clouds over land is considerably underestimated by PMW and IR products over almost the entire intensity range. The IR-based precipitation estimates for deep convective clouds considerably overestimate the intensity for both weak precipitation and cases where precipitation was not detected by the DPR-Ku algorithm. The findings reveal the characteristics of the biases of the products depend on the associated cloud types, which suggests consideration of the cloud type information to improve satellite-based precipitation estimates.
- Published
- 2018
43. Amorphous TiO2/p-Si Heterojunction Photodiode Prepared by Low-Temperature Atomic Layer Deposition
- Author
-
Jaehong Yoon, Han-Bo-Ram Lee, Rizwan Khan, Il Kwon Oh, and Hyungjun Kim
- Subjects
0301 basic medicine ,Materials science ,business.industry ,Heterojunction ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Photodiode ,law.invention ,Amorphous solid ,03 medical and health sciences ,Atomic layer deposition ,030104 developmental biology ,law ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business - Published
- 2018
44. Status and Qualification Test of Feeder Main Busbar Joint for ITER Magnet System
- Author
-
Y. Ilyin, Arnaud Devred, Hyungjun Kim, Bertrand Peluso, P. Decool, Naoyuki Sato, Chen-yu Gung, Neil Mitchell, Julien Laquiere, and Jaromir Farek
- Subjects
Current distribution ,Computer science ,Manufacturing process ,business.industry ,Busbar ,Sample (statistics) ,Structural engineering ,Welding ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Electronic, Optical and Magnetic Materials ,Test (assessment) ,law.invention ,law ,Magnet ,0103 physical sciences ,Electrical and Electronic Engineering ,010306 general physics ,business ,Joint (geology) - Abstract
This paper describes the result of the ITER feeder main busbar joint sample qualification test as confirmation of the requirement of busbar joint resistance, 2 nΩ at 70 kA at zero background field, as well as that of joint performance in various magnetic fields to investigate stability and current distribution characteristics in feeder-type joint box. The results support the quality of the joint manufacturing process for ITER main busbar joint. The qualification sample design was prepared to be tested in SULTAN facility. The SULTAN joint sample consists of joints to be qualified at the level of the peak field and upper terminations. In bottom joints, twin-box feeder-type praying hands configuration is applied. In upper terminations, one of them is made with solder-filled cable for optimum current distribution. The other takes the same length of the copper sole and contact with the busbar cable as those positioned in bottom of the sample. The sample undergoes a test program, which includes joint resistance measurement, ac losses, and stability margin test. The outcomes of those test programs are reported.
- Published
- 2018
45. Magnet Infrastructure Facilities for ITER (MIFI): Description and Activities Overview
- Author
-
R. Piccin, P. Tena, Y. Bale, Alexander Vostner, L. Nicolas, N. Clayton, Hyungjun Kim, Julien Laquiere, Baptiste Martin, S. Cerignat, S. Bremond, Sebastien Huygen, O. Dumoulin, A. Laurenti, A. Fontaine, E. Pignoly, Chen-yu Gung, P. Bayetti, Arnaud Devred, T. Brilleman, Bertrand Peluso, K. Doshi, Hamada Kazuya, J. Y. Journeaux, P. Decool, C. Boyer, Neil Mitchell, P. Michelier, and Alexandre Torre
- Subjects
Engineering ,Work organization ,business.industry ,MiFi ,Superconducting magnet ,Storage area ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Electronic, Optical and Magnetic Materials ,Acceptance testing ,Magnet ,0103 physical sciences ,Qualification testing ,Systems engineering ,Instrumentation (computer programming) ,Electrical and Electronic Engineering ,010306 general physics ,business - Abstract
ITER magnets are in the final phases of production and are preparing for the upcoming assembly challenges. The ITER magnet team has expressed the need for close-range support labs in order to perform qualification tests, procedure tuning, mockup testing, site acceptance tests, as well as training of assembly staff and logistics management. In the framework of its general support to the ITER project, CEA's Institute for Magnetic Fusion Research proposed a support structure in line with this need on CEA Cadarache premises. In July 2014, the MIFI agreement (Magnet Infrastructure Facilities for ITER) was signed between ITER organization and CEA. It led to the creation of four laboratories and a storage area dedicated to magnet instrumentation components. This paper gives a general description of the work organization in MIFI, and describes the main ongoing activities with specific focuses on critical qualification activities like high-voltage testing and diagnostic of Glass–Kapton–Glass resin impregnated insulation and the scale 1 mock-up and test of the intermediate outer intercoil structure assembly procedure.
- Published
- 2018
46. High-Performance Ink-Synthesized Cu-Gate Thin-Film Transistor with Diffusion Barrier Formation
- Author
-
Wan Joo Maeng, Hyungjun Kim, Taewook Nam, Whang Je Woo, and Il Kwon Oh
- Subjects
010302 applied physics ,Materials science ,Diffusion barrier ,Inkwell ,business.industry ,Transistor ,Metals and Alloys ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Temperature stress ,law.invention ,Reliability (semiconductor) ,Mechanics of Materials ,Thin-film transistor ,law ,0103 physical sciences ,Materials Chemistry ,Optoelectronics ,Positive bias ,0210 nano-technology ,business ,Layer (electronics) - Abstract
The improved electrical properties of Cu-gate thin-film transistors (TFTs) using an ink-synthesizing process were studied; this technology enables a low-cost and large area process for the display industry. We investigated the film properties and the effects of the ink-synthesized Cu layer in detail with respect to device characteristics. The mobility and reliability of the devices were significantly improved by applying a diffusion barrier at the interface between the Cu gate and the gate insulator. By using a TaN diffusion barrier layer, considerably improved and stabilized ink-Cu gated TFTs could be realized, comparable to sputtered-Cu gated TFTs under positive bias temperature stress measurements.
- Published
- 2018
47. Improved Synapse Device With MLC and Conductance Linearity Using Quantized Conduction for Neuromorphic Systems
- Author
-
Taesu Kim, Hyunsang Hwang, Hyungjun Kim, Jeonghwan Song, Changhyuck Sung, Jae-Joon Kim, and Seokjae Lim
- Subjects
010302 applied physics ,Materials science ,Programmable metallization cell ,business.industry ,Conductance ,Linearity ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Hafnium compounds ,Thermal conduction ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Neuromorphic engineering ,Synaptic device ,0103 physical sciences ,Degradation (geology) ,Optoelectronics ,Electrical and Electronic Engineering ,0210 nano-technology ,business - Abstract
In this letter, we demonstrate the conductive-bridging RAM (CBRAM) with excellent multi-level cell (MLC) and linear conductance characteristics for an artificial synaptic device of neuromorphic systems. Our findings show that inherent characteristics of CBRAM can achieve the linear conductance and MLC characteristics as a product of an integer unit of the conductance. However, uncontrolled metal-ion injection into the switching layer results in a significant degradation of device uniformity, leading to degradation in the classification accuracy. Thus, we introduce a multi-layer CBRAM configuration (Cu/HfO2/Ta/Cu2S/W) to control the ionic motion in electrolytes. As a result of device engineering, highly improved classification accuracy is achieved using CIFAR-10 data set.
- Published
- 2018
48. Water-Erasable Memory Device for Security Applications Prepared by the Atomic Layer Deposition of GeO2
- Author
-
Hyoung Seok Moon, Bonggeun Shong, Yujin Lee, Han-Bo-Ram Lee, Chang Mo Yoon, Jae Min Myoung, Hyun Gu Kim, Il Kwon Oh, Su Jeong Lee, Hyungjun Kim, and Jeong Gyu Song
- Subjects
010302 applied physics ,Fabrication ,Materials science ,business.industry ,General Chemical Engineering ,Film density ,02 engineering and technology ,General Chemistry ,Surface finish ,Surface reaction ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic layer deposition ,Dielectric layer ,0103 physical sciences ,Materials Chemistry ,Optoelectronics ,Thin film ,0210 nano-technology ,business ,Stoichiometry - Abstract
We have investigated the atomic layer deposition (ALD) of GeO2 thin films that dissolve in water rapidly and have excellent electrical properties for use in memory devices. The growth characteristics based on surface reactions during the ALD process are discussed by correlation with experimental results and atomistic theoretical calculation. Compared to sputtered GeO2 films, the ALD-grown GeO2 is perfect, pure, and water-soluble at room temperature and has better electrical properties for use as the dielectric layer in memory devices. The superior film properties of ALD GeO2 are attributed to the higher film density, high purity, low roughness, and highly stoichiometric film composition. Finally, we demonstrate the fabrication of charge-trapping memory (CTM) devices with ALD GeO2, and that the electrical information stored in the CTM can be eliminated immediately by exposure to one droplet of water at room temperature. Thus, ALD GeO2 could find widespread application in the fabrication of secure memory de...
- Published
- 2018
49. Enhanced Light Stability of InGaZnO Thin-Film Transistors by Atomic-Layer-Deposited Y2O3 with Ozone
- Author
-
Hanearl Jung, Woo-Hee Kim, Jae Min Myoung, Whang Je Woo, Hyungjun Kim, Bo Eun Park, Yun Cheol Kim, Christian Dussarrat, Satoko Gatineau, Il Kwon Oh, and Su Jeong Lee
- Subjects
010302 applied physics ,Materials science ,Passivation ,business.industry ,Transistor ,02 engineering and technology ,Plasma ,021001 nanoscience & nanotechnology ,01 natural sciences ,Threshold voltage ,law.invention ,Atomic layer deposition ,law ,Thin-film transistor ,0103 physical sciences ,Degradation (geology) ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Layer (electronics) - Abstract
We report the effect of Y2O3 passivation by atomic layer deposition (ALD) using various oxidants, such as H2O, O2 plasma, and O3, on In–Ga–Zn–O thin-film transistors (IGZO TFTs). A large negative shift in the threshold voltage (Vth) was observed in the case of the TFT subjected to the H2O-ALD Y2O3 process; this shift was caused by a donor effect of negatively charged chemisorbed H2O molecules. In addition, degradation of the IGZO TFT device performance after the O2 plasma-ALD Y2O3 process (field-effect mobility (μ) = 8.7 cm2/(V·s), subthreshold swing (SS) = 0.77 V/dec, and Vth = 3.7 V) was observed, which was attributed to plasma damage on the IGZO surface adversely affecting the stability of the TFT under light illumination. In contrast, the O3-ALD Y2O3 process led to enhanced device stability under light illumination (ΔVth = −1 V after 3 h of illumination) by passivating the subgap defect states in the IGZO surface region. In addition, TFTs with a thicker IGZO film (55 nm, which was the optimum thicknes...
- Published
- 2018
50. Comparative study of the growth characteristics and electrical properties of atomic-layer-deposited HfO2 films obtained from metal halide and amide precursors
- Author
-
Woo-Hee Kim, Seung Gi Seo, Han-Bo-Ram Lee, Byung Chul Yeo, Hyungjun Kim, Il Kwon Oh, Bo Eun Park, and Jukka T. Tanskanen
- Subjects
010302 applied physics ,Materials science ,Graphene ,business.industry ,Gate dielectric ,Nucleation ,02 engineering and technology ,General Chemistry ,Dielectric ,021001 nanoscience & nanotechnology ,01 natural sciences ,law.invention ,Atomic layer deposition ,Semiconductor ,Chemical engineering ,law ,0103 physical sciences ,Materials Chemistry ,Thin film ,0210 nano-technology ,business ,Leakage (electronics) - Abstract
Downscaling of complementary metal-oxide semiconductor (CMOS) gate stacks requires the introduction of ultra-thin and high-k dielectrics such as HfO2. Atomic layer deposition (ALD) is an excellent technique for producing high-quality high-k films. During ALD, chemical reactions on the substrate surface involve multiple processes that affect the chemical and electrical properties of the deposited films. Thus, the choice of an appropriate precursor for ALD is critical for obtaining high-quality high-k films, leading to good device performance. The aim of this study is to understand the surface reactions during the film growth along with the evaluation of the electrical properties of HfO2 deposited using two different Hf precursors, HfCl4 and Hf(N(CH3)2)4. The growth behavior and electrical performance of ALD HfO2 thin films obtained using the two Hf precursors and H2O as an oxidant at 250 °C are studied comparatively and discussed as a function of the process parameters, together with surface-reaction energetics determined by the density functional theory. Compared to Hf(N(CH3)2)4, the HfCl4 shows unfavorable nucleation behavior on the starting Si–OH surfaces. In addition, a more stoichiometric HfO2 film results from HfCl4 owing to its high reactivity, leading to lower leakage currents of Si-based devices than that of the film obtained from Hf(N(CH3)2)4. Further, HfCl4 showed better nucleation on a 2D graphene substrate, leading to superior electrical performance in graphene-based field effect transistors. These results provide practical insights on selecting a suitable Hf precursor for producing gate dielectric layers for future nanoelectronics.
- Published
- 2018
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.