210 results on '"Jin Woong Lee"'
Search Results
2. Development of a Real-Time Tractor Model for Gear Shift Performance Verification
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Gyuha Han, Da-Vin Ahn, Doyeop Kwon, Heung-Sub Kim, Young-Jun Park, and Jin Woong Lee
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gear shift performance ,tractor simulation model ,real-time simulation ,dual-clutch transmission ,Agriculture (General) ,S1-972 - Abstract
Verification of the system is essential during the development of a tractor; however, there are cost and time limitations when verification is performed on an actual tractor. To solve this problem, we developed a tractor model for real-time simulation to verify the gear shift performance of the tractor and evaluate the control algorithm. This study examined and modeled a dual-clutch transmission (DCT)-type 105 kW class tractor. The proportional control valve, synchronizer, and clutch were modeled to accurately implement the shift behavior, and the developed individual model was verified based on actual individual product test data. The 45 s driving simulation was conducted to confirm whether real-time simulation of the entire developed tractor model was possible and whether it simulated the behavior of the target tractor well. The driving simulation results confirmed that the driving speed of the tractor model matched the engine speed, transmission gear ratio, and tractor specifications, and the gear shift performance of the tractor model according to the number of gears was confirmed. The simulated model thus satisfies the characteristics of the target tractor and can be used to verify the gear shift performance, indicating that the model can verify the performance of the control algorithm in real time.
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- 2023
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3. Natural bone-mimicking nanopore-incorporated hydroxyapatite scaffolds for enhanced bone tissue regeneration
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Chansong Kim, Jin Woong Lee, Jun Hyuk Heo, Cheolhyun Park, Dai-Hwan Kim, Gyu Sung Yi, Ho Chang Kang, Hyun Suk Jung, Hyunjung Shin, and Jung Heon Lee
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Natural bone-mimicking ,Nanopore ,Hydroxyapatite ,Scaffold ,Bone graft material ,Medical technology ,R855-855.5 - Abstract
Abstract Background A considerable number of studies has been carried out to develop alloplastic bone graft materials such as hydroxyapatite (HAP) that mimic the hierarchical structure of natural bones with multiple levels of pores: macro-, micro-, and nanopores. Although nanopores are known to play many essential roles in natural bones, only a few studies have focused on HAPs containing them; none of those studies investigated the functions of nanopores in biological systems. Method We developed a simple yet powerful method to introduce nanopores into alloplastic HAP bone graft materials in large quantities by simply pressing HAP nanoparticles and sintering them at a low temperature. Results The size of nanopores in HAP scaffolds can be controlled between 16.5 and 30.2 nm by changing the sintering temperature. When nanopores with a size of ~ 30.2 nm, similar to that of nanopores in natural bones, are introduced into HAP scaffolds, the mechanical strength and cell proliferation and differentiation rates are significantly increased. The developed HAP scaffolds containing nanopores (SNPs) are biocompatible, with negligible erythema and inflammatory reactions. In addition, they enhance the bone regeneration when are implanted into a rabbit model. Furthermore, the bone regeneration efficiency of the HAP-based SNP is better than that of a commercially available bone graft material. Conclusion Nanopores of HAP scaffolds are very important for improving the bone regeneration efficiency and may be one of the key factors to consider in designing highly efficient next-generation alloplastic bone graft materials.
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- 2022
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4. Optimal Control of Semi-Active Suspension for Agricultural Tractors Using Linear Quadratic Gaussian Control
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Da-Vin Ahn, Kyeongdae Kim, Jooseon Oh, Jaho Seo, Jin Woong Lee, and Young-Jun Park
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agricultural tractor ,linear quadratic Gaussian control ,ride vibration reduction ,semi-active suspension ,Kalman filter ,observer design ,Chemical technology ,TP1-1185 - Abstract
In this study, a semi-active suspension based on a hydro-pneumatic mechanism was designed to minimize the ride vibration using a suspension control algorithm. The performance of the algorithm was critical for controlling the characteristics of the target tractor. A linear-quadratic-Gaussian (LQG) optimal control algorithm was designed as a semi-active suspension control algorithm. The plant model for developing this algorithm was based on the parameters of an actual tractor. The rear suspension deflection was represented by a Kalman-filter-based state observer feedback to estimate the state variables that were difficult to measure. The designed state observer of the LQG controller was validated in terms of an accuracy index. The estimated vertical velocity and acceleration accuracies of the cabin were 83% and 79%, respectively. The performance of the designed controller was validated in terms of a performance index by comparing the performance of a tractor equipped with a rear rubber mount with that of one equipped with a semi-active suspension. The peak and root-mean-square values of the vertical acceleration of the cabin were reduced by up to 48.97% and 47.06%, respectively. This study could serve as a basis for the application of the control algorithm to systems with similar characteristics, thereby reducing system costs.
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- 2023
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5. Development of a rolling angle estimation algorithm to improve the performance of implement leveling-control systems for agricultural tractors
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Ji Hun Yu, Jin Kam Park, Su Hwan Cheon, Seo Jung Byeon, and Jin Woong Lee
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Mechanical engineering and machinery ,TJ1-1570 - Abstract
Agricultural tractors are connected with various implements such as plow, baler, rotovator, and loader for performing agricultural work. In particular, the rotovator is used to crush and uniformly spread the soil after plowing operations. However, achieving uniformly spread soil and flattened fields using rotovator can be extremely challenging, because the soil is often pushed to a particular side or remains on a slope owing to the variations in soil composition, plowing depth, and the skill level of workers, which consequently affects the transplantation work. This study aims to analyze the prediction accuracy of the implement and tractor attitudes as a reference standard by (a) developing an algorithm to predict the implement attitude based on the hitch height, support points of the lower link and lift rod, and distance between the lower links, through four-section link mathematical modeling for a three-point hitch system, and (b) using an observer to predict the tractor attitude using a Kalman filter with gyroscopic and acceleration sensors. We developed a control algorithm using the gyroscopic and acceleration information from the sensor to improve the precision and adjustment speed of the conventional tractor–implement leveling-control system. In addition, the performance improvement was verified by comparing the conventional and proposed systems. The results revealed that the error rates in the proposed system were up to 72% less than those of the conventional system, implying that the control performance of the stated system could be improved by reducing the implement attitude estimation error and tractor attitude measurement delay.
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- 2022
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6. A study on the bio-applicability of aqueous-dispersed van der Waals 1-D material Nb2Se9 using poloxamer
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Sudong Chae, Seungbae Oh, Kyung Hwan Choi, Jin Woong Lee, Jiho Jeon, Zhixiang Liu, Cong Wang, Changmo Lim, Xue Dong, Chaeheon Woo, Ghulam Asghar, Liyi Shi, Joohoon Kang, Sung Jae Kim, Si Young Song, Jung Heon Lee, Hak Ki Yu, and Jae-Young Choi
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Medicine ,Science - Abstract
Abstract In this research, dispersion of a new type of one-dimensional inorganic material Nb2Se9, composed of van der Waals bonds, in aqueous solution for bio-application study were studied. To disperse Nb2Se9, which exhibits hydrophobic properties in water, experiments were carried out using a block copolymer (poloxamer) as a dispersant. It was confirmed that PPO, the hydrophobic portion of Poloxamer, was adsorbed onto the surface of Nb2Se9, and PEO, the hydrophilic portion, induced steric hinderance to disperse Nb2Se9 to a size of 10 nm or less. To confirm the adaptability of muscle cells C2C12 to the dispersed Nb2Se9 using poloxamer 188 as dispersant, a MTT assay and a live/dead assay were performed, demonstrating improvement in the viability and proliferation of C2C12 cells.
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- 2021
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7. Process for Integrating Constructability into the Design Phase in High-Rise Concrete Buildings: Focused on Temporary Work
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Jin Woong Lee, Kyuman Cho, Taeyon Hwang, Ju-yeon Han, and Taehoon Kim
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constructability ,design phase ,high-rise concrete buildings ,information flow ,dependency structure matrix ,Systems of building construction. Including fireproof construction, concrete construction ,TH1000-1725 - Abstract
Abstract With the increase in high-rise building construction, failure to consider constructability in the design phase can result in huge wastes in the construction phase, as well as losing opportunities for design improvement. However, existing approaches for reflecting constructability rely heavily on reviews, resulting in an inefficient decision-making process. Thus, by considering appropriate timing and detail levels when applying construction knowledge, this study proposes a process for integrating constructability activities related to temporary work into the design phase in high-rise concrete buildings. Through an investigation of information-dependency relationships, 22 constructability activities were linked with 33 design activities. Further, these activities’ implementation processes were constructed based on optimized information flows from a partitioned dependency structure matrix. The results of this study can help a project team address constructability issues at the appropriate time during the design process and will contribute to improving the efficiency of the overall project operation in high-rise building construction.
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- 2018
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8. Is it possible to reduce intra-hospital transport time for computed tomography evaluation in critically ill cases using the Easy Tube Arrange Device?
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Kyung Hyeok Song, Sung Uk Cho, Jin Woong Lee, Yong Chul Cho, Won Joon Jeong, Yeon Ho You, Seung Ryu, Seung Whan Kim, In Sool Yoo, and Ki Hyuk Joo
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critical illness ,hospitals ,transportation ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Objective Patients are often transported within the hospital, especially in cases of critical illness for which computed tomography (CT) is performed. Since increased transport time increases the risks of complications, reducing transport time is important for patient safety. This study aimed to evaluate the ability of our newly invented device, the Easy Tube Arrange Device (ETAD), to reduce transport time for CT evaluation in cases of critical illness. Methods This prospective randomized control study included 60 volunteers. Each participant arranged five or six intravenous fluid lines, monitoring lines (noninvasive blood pressure, electrocardiography, central venous pressure, arterial catheter), and therapeutic equipment (O2 supply device, Foley catheter) on a Resusci Anne mannequin. We measured transport time for the CT evaluation by using conventional and ETAD method. Results The median transport time for CT evaluation was 488.50 seconds (95% confidence interval [CI], 462.75 to 514.75) and, 503.50 seconds (95% CI, 489.50 to 526.75) with 5 and 6 fluid lines using the conventional method and 364.50 seconds (95% CI, 335.00 to 388.75), and 363.50 seconds (95% CI, 331.75 to 377.75) with ETAD (all P
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- 2018
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9. Author Correction: A study on the bio-applicability of aqueous-dispersed van der Waals 1-D material Nb2Se9 using poloxamer
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Sudong Chae, Seungbae Oh, Kyung Hwan Choi, Jin Woong Lee, Jiho Jeon, Zhixiang Liu, Cong Wang, Changmo Lim, Xue Dong, Chaeheon Woo, Ghulam Asghar, Liyi Shi, Joohoon Kang, Sung Jae Kim, Si Young Song, Jung Heon Lee, Hak Ki Yu, and Jae‑Young Choi
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Medicine ,Science - Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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- 2021
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10. Direction of the J-Tip of the Guidewire to Decrease the Malposition Rate of an Internal Jugular Vein Catheter
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Byeong jun Ahn, Sung Uk Cho, Won Joon Jeong, Yeon Ho You, Seung Ryu, Jin Woong Lee, In Sool Yoo, and Yong chul Cho
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catheterization, central venous ,jugular vein ,malposition ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Background We hypothesized that the direction of the J-tip of the guidewire during insertion into the internal jugular vein (IJV) might determine its ultimate location. Methods In this study, 300 patients between the ages of 18 and 99 years who required central venous catheterization via IJV in the emergency department enrolled for randomization. IVJ catheterization was successful in 285 of 300 patients. An independent operator randomly prefixed the direction of the J-tip of the guidewire to one of three directions. Based on the direction of the J-tip, patients were allocated into three groups: the J-tip medial-directed group (Group A), the lateral-directed group (Group B), or the downward-directed group (Group C). Postoperative chest radiography was performed on all patients in order to visualize the location of the catheter tip. A catheter is considered malpositioned if it is not located in the superior vena cava or right atrium. Results Of the total malpositioned catheter tips (8 of 285; 2.8%), the majority (5 of 8; 62.5%) entered the contralateral subclavian vein, 2 (25.0%) were complicated by looping, and 1 (12.5%) entered the ipsilateral subclavian vein. According to the direction of the J-tip of the guidewire, the incidence of malpositioning of the catheter tip was 4 of 92 in Group A (4.3%), 4 of 96 in Group B (4.2%), and there were no malpositions in Group C. There were no significant differences among the three groups (p = 0.114). Conclusions The direction of the J-tip of the guidewire had no statistically significant effect on incidence of malpositioned tips.
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- 2015
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11. Does Combining Biomarkers and Brain Images Provide Improved Prognostic Predictive Performance for Out-Of-Hospital Cardiac Arrest Survivors before Target Temperature Management?
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Seung Ha Son, In Ho Lee, Jung Soo Park, In Sool Yoo, Seung Whan Kim, Jin Woong Lee, Seung Ryu, Yeonho You, Jin Hong Min, Yong Chul Cho, Won Joon Jeong, Se Kwang Oh, Sung Uk Cho, Hong Joon Ahn, Changshin Kang, Dong Hun Lee, Byung Kook Lee, and Chun Song Youn
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out-of-hospital cardiac arrest ,prognosis ,neuron-specific enolase ,magnetic resonance imaging ,computed tomography ,Medicine - Abstract
We examined whether combining biomarkers measurements and brain images early after the return of spontaneous circulation improves prognostic performance compared with the use of either biomarkers or brain images for patients with cardiac arrest following target temperature management (TTM). This retrospective observational study involved comatose out-of-hospital cardiac arrest survivors. We analyzed neuron-specific enolase levels in serum (NSE) or cerebrospinal fluid (CSF), grey-to-white matter ratio by brain computed tomography, presence of high signal intensity (HSI) in diffusion-weighted imaging (DWI), and voxel-based apparent diffusion coefficient (ADC). Of the 58 patients, 33 (56.9%) had poor neurologic outcomes. CSF NSE levels showed better prognostic performance (area under the curve (AUC) 0.873, 95% confidence interval (CI) 0.749−0.950) than serum NSE levels (AUC 0.792, 95% CI 0.644−0.888). HSI in DWI showed the best prognostic performance (AUC 0.833, 95% CI 0.711−0.919). Combining CSF NSE levels and HSI in DWI had better prognostic performance (AUC 0.925, 95% CI 0.813−0.981) than each individual method, followed by the combination of serum NSE levels and HSI on DWI and that of CSF NSE levels and the percentage of voxels of ADC (AUC 0.901, 95% CI 0.792−0.965; AUC 0.849, 95% CI 0.717−0.935, respectively). Combining CSF/serum NSE levels and HSI in DWI before TTM improved the prognostic performance compared to either each individual method or other combinations.
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- 2020
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12. Engine Speed Control System for Improving the Fuel Efficiency of Agricultural Tractors for Plowing Operations
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Jin Woong Lee, Su Chul Kim, Jooseon Oh, Woo-Jin Chung, Hyun-Woo Han, Ji-Tae Kim, and Young-Jun Park
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agricultural tractor ,fuel-saving ,control system design ,control algorithm ,load sensing ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This study was conducted to develop a load-sensitive engine speed control system to maximize the fuel efficiency of an agricultural tractor. The engine speed controller was developed through a model-based design approach using a tractor simulation model. The simulated engine speed and torque values were measured with an average error range of 1.4−4.9% compared to results obtained from field experiments. Using the tractor model, the gain parameters of the proportional−integral (PI) controller were optimized under the step, ramp, and actual load conditions. The simulation results using the actual load showed that the engine speed could be adjusted to within 2−3% of the desired value using the proposed engine speed controller. The throttle control system was constructed using four parts of a tractor engine, a microprocessor with an engine speed control algorithm, a throttle actuator, and a data acquisition system. Using the developed system, the operating engine speed values showed an average 1.17 % error compared to the desired engine speed. Three fuel efficiency parameters were used for evaluating the fuel-saving performance of the control system: specific volumetric fuel consumption (SVFC), fuel consumption per tilled area (FCA), and fuel consumption per work hour (FC). The values for SVFC, FCA, and FC obtained from the engine speed control system during plowing operations were 23.03−57.87%, 4.11−42.06%, and −7.24−38.48%, respectively, showing an improvement over the same operations without the control system.
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- 2019
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13. Effect of clutch control to improve launch quality for a power shuttle tractor during launching.
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Da-Vin Ahn, Kyeongdae Kim, Kyujeong Choi, Jin Woong Lee, Jeong-Gil Kim, Jihun Yu, Heung-Sub Kim, Jaho Seo, and Young-Jun Park
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- 2024
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14. A Deep Learning Approach to Powder X-Ray Diffraction Pattern Analysis: Addressing Generalizability and Perturbation Issues Simultaneously.
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Byung Do Lee, Jin-Woong Lee, Junuk Ahn, Seonghwan Kim 0005, Woon Bae Park, and Kee-Sun Sohn
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- 2023
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15. Powder X-Ray Diffraction Pattern Is All You Need for Machine-Learning-Based Symmetry Identification and Property Prediction.
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Byung Do Lee, Jin-Woong Lee, Woon Bae Park, Joonseo Park, Min-Young Cho, Satendra Pal Singh, Myoungho Pyo, and Kee-Sun Sohn
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- 2022
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16. Large-Area Piezoresistive Tactile Sensor Developed by Training a Super-Simple Single-Layer Carbon Nanotube-Dispersed Polydimethylsiloxane Pad.
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Min-Young Cho, Jin-Woong Lee, Chaewon Park, Byung Do Lee, Joon Seok Kyeong, Eun Jeong Park, Kee Yang Lee, and Kee-Sun Sohn
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- 2022
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17. The Flora of Jindo’s Mt. Cheomchal In Jeollanamdo
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Jun Hwang and Jin-Woong Lee
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General Engineering ,General Earth and Planetary Sciences ,General Environmental Science - Published
- 2023
18. Multi-variable Bayesian optimization for a new composition with high Na+ conductivity in the Na3PS4 family
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Jung Young Seo, Sunggeun Shim, Jin-Woong Lee, Byung Do Lee, Sangwon Park, Woon Bae Park, Suyeon Han, Myoungho Pyo, and Kee-Sun Sohn
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Renewable Energy, Sustainability and the Environment ,General Materials Science ,General Chemistry - Abstract
A Bayesian optimization (BO) algorithm is employed to discover new Na3PS4 compositions with a high σion in a multi-dimensional co-doped search space.
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- 2022
19. Detection of Testicular Torsion With Preserved Intratesticular Flow By Point of Care Ultrasound in the Emergency Department: A Case Report
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Dong Young Lee, Sung Hyeok Lee, Jung A Yoon, Changshin Kang, Yong Chul Cho, Hong Joon Ahn, Jung Soo Park, Seung Ryu, Yeonho You, Seung Whan Kim, Jin Woong Lee, and Won Joon Jeong
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Male ,Adolescent ,Point-of-Care Systems ,Scrotum ,Emergency Medicine ,Humans ,Emergency Service, Hospital ,Acute Pain ,Spermatic Cord Torsion ,Ultrasonography - Abstract
Ultrasonography is an effective diagnostic tool for testicular torsion (TT), which is typically characterized by the absence of blood flow in the affected testicle on color Doppler mode. However, there are a few reported cases of TT with symmetrical preserved flow. We report a case of TT with the preserved intratesticular flow on color Doppler ultrasound.A 14-year-old boy was admitted due to sudden-onset right scrotal pain. Point-of-care ultrasound (POCUS) revealed that the right testicle was larger than the left. The intratesticular flow in both testicles was preserved. Radiology-performed ultrasound confirmed the preserved intratesticular flow observed on POCUS, but also demonstrated a whirlpool sign of the right spermatic cord. TT was confirmed surgically. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians should investigate the presence of intratesticular blood flow and the whirlpool sign of the spermatic cord or other ultrasound features suggestive of TT, even if testicular blood flow is preserved. Suspicion of TT from POCUS findings warrants further evaluation to preserve the patient's fertility.
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- 2022
20. Argyrodite configuration determination for DFT and AIMD calculations using an integrated optimization strategy
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Byung Do Lee, Jin-Woong Lee, Joonseo Park, Min Young Cho, Woon Bae Park, and Kee-Sun Sohn
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General Chemical Engineering ,General Chemistry - Abstract
When constructing a partially occupied model structure for use in density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations, the selection of appropriate configurations has been a vexing issue. We suggest a reasonable strategy to sort out this issue.
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- 2022
21. Silicon oxycarbide-derived hierarchical porous carbon nanoparticles with tunable pore structure for lithium-sulfur batteries
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Sung Eun Wang, Min Ji Kim, Jin-Sung Park, Jin Woong Lee, Do Woong Yoon, Youngsin Kim, Jung Hyun Kim, Yun Chan Kang, and Dae Soo Jung
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General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
22. Bioinspired Adenosine Triphosphate as an 'All-In-One' Green Flame Retardant via Extremely Intumescent Char Formation
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Cheol Hyun Park, Jun Hyuk Heo, Jin Woong Lee, Min Jeong Kim, S.H. Jeong, and Jung Heon Lee
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Materials science ,Flame test ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Limiting oxygen index ,chemistry.chemical_compound ,fluids and secretions ,Chemical engineering ,chemistry ,Blowing agent ,General Materials Science ,Char ,0210 nano-technology ,Intumescent ,Fire retardant ,Flammability ,Polyurethane - Abstract
The development of eco-friendly flame retardants is crucial due to the hazardous properties of most conventional flame retardants. Herein, adenosine triphosphate (ATP) is reported to be a highly efficient "all-in-one" green flame retardant as it consists of three essential groups, which lead to the formation of char with extreme intumescence, namely, three phosphate groups, providing an acid source; one ribose sugar, working as a char source; and one adenine, acting as a blowing agent. Polyurethane foam was used as a model flammable material to demonstrate the exceptional flame retardancy of ATP. The direct flammability tests have clearly shown that the ATP-coated polyurethane (PU) foam almost did not burn upon exposure to the torch flame. Importantly, ATP exhibits an extreme volume increase, whereas general phosphorus-based flame retardants show a negligible increase in volume. The PU foam coated with 30 wt % of ATP (PU-ATP 30 wt %) exhibits a significant reduction in the peak heat release rate (94.3%) with a significant increase in the ignition time, compared to bare PU. In addition, PU-ATP 30 wt % exhibits a high limiting oxygen index (LOI) value of 31% and HF-1 rating in the UL94 horizontal burning foamed material test. Additionally, we demonstrated that ATP's flame retardancy is sufficient for other types of matrices such as cotton, as confirmed from the results of the standardized ASTM D6413 test; cotton-ATP 30 wt % exhibits an LOI value of 32% and passes the vertical flame test. These results strongly suggest that ATP has great potential to be used as an "all-in-one" green flame retardant.
- Published
- 2021
23. A Reasonable DFT Calculation Method for Hybrid Organic-Inorganic Halide Perovskites
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Jin-Woong Lee and Woon Bae Park
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Materials science ,Band gap ,020502 materials ,Metals and Alloys ,Halide ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Effective mass (solid-state physics) ,0205 materials engineering ,Chemical physics ,Modeling and Simulation ,Organic inorganic ,Density functional theory ,0210 nano-technology - Abstract
Hybrid Organic-Inorganic Perovskites (HOIP) have received a great deal of attention as a key material for applications like solar cells and light emitting devices because of their many advantages, in spite of their stability and toxicity issues. Attempting to discover and characterize novel HOIPs using just an experimental approach would be prohibitively time-and-cost-consuming. Using theoretical or empirical calculations would greatly help. For these reasons, HOIP has been actively investigated using DFT (Density Functional Theory) calculations, which have significantly reduced research time and cost. However, the input model structure treatment needs to be standardized to avoid unnecessary complications. For this purpose, a sort of optimization of DFT calculation protocols for HOIPs is essential, because DFT calculation results are greatly affected by the input model structure arrangements and exchange-correlation functionals. In this paper, we used DFT to calculate the band gap, formation energy, and effective mass of the well-known cubic perovskite structure, methylammonium lead iodide (CH3NH3PbI3: MAPbI3) with and without the van der Waals function and SOC (Spin Orbit Coupling) and various geometrical molecule arrangements in the structure. In particular, the initial orientation of the ‘A’ site molecule in the input model structure was intensively investigated in terms of band gap, formation energy and effective mass. It was found that the relaxation-induced final structure was greatly influenced by the initial orientation of the molecule and thereby significantly affected the DFT-calculated result.
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- 2021
24. Structure and Ion Conductivity Study of Argyrodite (Li5.5PS4.5Cl1.5) according to Cooling Method
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Jin-Woong Lee and Sangwon Park
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Materials science ,020502 materials ,Argyrodite ,Metals and Alloys ,02 engineering and technology ,engineering.material ,Conductivity ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,Cooling rate ,0205 materials engineering ,Chemical engineering ,Modeling and Simulation ,engineering ,Solid-state battery ,Ionic conductivity ,0210 nano-technology - Abstract
All solid-state batteries (ASSBs) are now anticipated to be an ultimate solution to the persistent safety issues of conventional lithium-ion batteries (LIBs). Contemporary society’s expanding power demands and growing energy consumption require energy storage with greater reliability, safety and capacity, which cannot be easily achieved with current state-of-the-art liquid-electrolyte-based LIBs. In contrast, these conditions are expected to be met by implementing ASSBs with high-performance solid-state electrolytes (SSEs). In this work, we altered the microscopic structure and Li diffusional behaviors of argyrodites (Li6-xPS5-xCl1+x), which were precisely monitored with cooling protocols. It was shown that, at the cooling speed of -3 oC·h-1, as the cooling rate decreased, impurities in Li5.5PS4.5Cl1.5 such as LiCl and Li3PO4 gradually diminished and eventually disappeared. At the same time, differences in the lattice sizes of Li5.5PS4.5Cl1.5 crystallites gradually decreased, resulting in a single phase Li5.5PS4.5Cl1.5. It was also found that the Cl content of the 4d crystallographic sites increased, eventually contributing to the improvement in ionic conductivity. This work also revealed the effect of cooling rates on the crystallographic atomic arrangements, which became weaker as a decrease in x. The correlations between ionic conductivities and structural features were experimentally verified via XRD and solid-state NMR studies.
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- 2021
25. Synthesis of Y6-xCa1.5xSi11N20O:Ce3+ (x = 0 ~ 2.5) Oxynitride Phosphor with Broad Emission Wavelength for 1pc-LED
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Jin-Woong Lee and Joonseo Park
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Color rendering index ,Wavelength ,Materials science ,Rietveld refinement ,Activator (phosphor) ,Analytical chemistry ,General Materials Science ,Phosphor ,Crystal structure ,Luminescence ,Ion - Abstract
A Y6-xCa1.5xSi11N20O:Ce3+(x=2.5) oxynitride phosphor is synthesized at 1,750 oC in a mixed gas atmosphere of 5% H2 and 95 % N2 by using YN, Ca3N2, Si3N4, and CeO2 as raw material reagents. The crystal structure is a trigonal crystal system that has a P31c (no.159) space group and has lattice parameters of a, b = 9.8876(3), and c = 10.6806(4). This structure is an Er6Si11N20O structure type in which a Y6-xCa1.5xSi11N20O structure is formed by substituting a trivalent Y3+ element and a bivalent Ca2+ element at the position of Er element having an oxidation number of +3. Here, the charge difference caused by different oxidation numbers is balanced by the occupancy of a partially vacant 2c site and an O/N anion ratio in the Er6Si11N20O structure type. The Y6-xCa1.5xSi11N20O:Ce3+ (x = 2.5) phosphor is yellow powder with yellow luminescence; performing Rietveld refinement on the phosphor on the basis of the data obtained by XRD measurement results in the lattice parameters as described above. The Y6-xCa1.5xSi11N20O:Ce3+ (x = 2.5) phosphor has a broad emission band due to Ce3+ as an activator with the center wavelength of 565 nm. This phosphor has a broader emission band than a YAG:Ce3+ phosphor, which is a representative LED phosphor, and thus extends further into the blue and red spectrum ranges. Accordingly, this phosphor is an interesting phosphor that can be used for 1pc-LED with an improved color rendering index.
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- 2021
26. Optimal Composition of Li Argyrodite with Harmonious Conductivity and Chemical/Electrochemical Stability: Fine-Tuned Via Tandem Particle Swarm Optimization
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Sunggeun Shim, Woon Bae Park, Jungmin Han, Jinhyeok Lee, Byung Do Lee, Jin‐Woong Lee, Jung Yong Seo, S. J. Richard Prabakar, Su Cheol Han, Satendra Pal Singh, Chan‐Cuk Hwang, Docheon Ahn, Sangil Han, Kyusung Park, Kee‐Sun Sohn, and Myoungho Pyo
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General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,Medicine (miscellaneous) ,General Materials Science ,Biochemistry, Genetics and Molecular Biology (miscellaneous) - Abstract
A tandem (two-step) particle swarm optimization (PSO) algorithm is implemented in the argyrodite-based multidimensional composition space for the discovery of an optimal argyrodite composition, i.e., with the highest ionic conductivity (7.78 mS cm
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- 2022
27. Dendritic-Linear Copolymer and Dendron Lipid Nanoparticles for Drug and Gene Delivery
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Michael J. Poellmann, Kaila Javius-Jones, Caroline Hopkins, Jin Woong Lee, and Seungpyo Hong
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Pharmacology ,Drug Delivery Systems ,Polymers ,Organic Chemistry ,Biomedical Engineering ,Pharmaceutical Science ,Nanoparticles ,Bioengineering ,Micelles ,Biotechnology ,Polyethylene Glycols - Abstract
Polymers constitute a diverse class of macromolecules that have demonstrated their unique advantages to be utilized for drug or gene delivery applications. In particular, polymers with a highly ordered, hyperbranched structure─"dendrons"─offer significant benefits to the design of such nanomedicines. The incorporation of dendrons into block copolymer micelles can endow various unique properties that are not typically observed from linear polymer counterparts. Specifically, the dendritic structure induces the conical shape of unimers that form micelles, thereby improving the thermodynamic stability and achieving a low critical micelle concentration (CMC). Furthermore, through a high density of highly ordered functional groups, dendrons can enhance gene complexation, drug loading, and stimuli-responsive behavior. In addition, outward-branching dendrons can support a high density of nonfouling polymers, such as poly(ethylene glycol), for serum stability and variable densities of multifunctional groups for multivalent cellular targeting and interactions. In this paper, we review the design considerations for dendron-lipid nanoparticles and dendron micelles formed from amphiphilic block copolymers intended for gene transfection and cancer drug delivery applications. These technologies are early in preclinical development and, as with other nanomedicines, face many obstacles on the way to clinical adoption. Nevertheless, the utility of dendron micelles for drug delivery remains relatively underexplored, and we believe there are significant and dramatic advancements to be made in tumor targeting with these platforms.
- Published
- 2022
28. A Novel High-Performance TiO
- Author
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Sung Eun, Wang, Min Ji, Kim, Jin Woong, Lee, Jinyoung, Chun, Junghyun, Choi, Kwang Chul, Roh, Yun Chan, Kang, and Dae Soo, Jung
- Abstract
Protective surface coatings on Si anodes are promising for improving the electrochemical performance of lithium-ion batteries (LIBs). Nevertheless, most coating materials have severe issues, including low initial coulombic efficiency, structural fracture, morphology control, and complicated synthetic processing. In this study, a multifunctional TiO
- Published
- 2022
29. Discovery of Pb-free hybrid organic–inorganic 2D perovskites using a stepwise optimization strategy
- Author
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Byung Do Lee, Jin-Woong Lee, Minseuk Kim, Woon Bae Park, and Kee-Sun Sohn
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Mechanics of Materials ,Modeling and Simulation ,General Materials Science ,Computer Science Applications - Abstract
The current status of 2D organic–inorganic hybrid perovskites for use in photovoltaic (PV) and light-emitting diode (LED) applications lags far behind their 3D counterparts. Here, we propose a computational strategy for discovering novel perovskites with as few computing resources as possible. A tandem optimization algorithm consisting of an elitism-reinforced nondominated sorting genetic algorithm (NSGA-II) and a multiobjective Bayesian optimization (MOBO) algorithm was used for density functional theory (DFT) calculations. The DFT-calculated band gap and effective mass were taken as objective functions to be optimized, and the constituent molecules and elements of a Ruddlesden–Popper (RP) structure (n = 2) were taken as decision variables. Fourteen previously unknown RP perovskite candidates for PV and LED applications were discovered as a result of the NSGA-II/MOBO algorithm. Thereafter, more accurate DFT calculations based on the HSE06 exchange correlation functional and ab initio molecular dynamics (AIMD) were conducted for the discovered 2D perovskites to ensure their validity.
- Published
- 2022
30. Unravelling the Nature of the Intrinsic Complex Structure of Binary-Phase Na-Layered Oxides
- Author
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Anil K. Paidi, Woon Bae Park, Prakash Ramakrishnan, Seong‐Hun Lee, Jin‐Woong Lee, Kug‐Seung Lee, Hyungju Ahn, Tongchao Liu, Jihyeon Gim, Maxim Avdeev, Myoungho Pyo, Jung Inn Sohn, Khalil Amine, Kee‐Sun Sohn, Tae Joo Shin, Docheon Ahn, and Jun Lu
- Subjects
Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Abstract
The layered sodium transition metal oxide, NaTMO
- Published
- 2022
31. Cyan-Light-Emitting Chalcogenometallate Phosphor, KGaS2:Eu2+, for Phosphor-Converted White Light-Emitting Diodes
- Author
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Satendra Pal Singh, Woon Bae Park, Kee-Sun Sohn, Minseuk Kim, Jin-Woong Lee, and Sunggeun Shim
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010405 organic chemistry ,business.industry ,Chemistry ,Cyan ,Phosphor ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,White light ,Optoelectronics ,Physical and Theoretical Chemistry ,business ,Visible spectrum ,Diode - Abstract
A novel KGaS2 phosphor host that emits a cyan light was discovered to fill the cyan gap in the visible spectrum of phosphor-converted white light-emitting diodes (pc-wLEDs). KGaS2, belonging to the...
- Published
- 2021
32. Discovery of Lead-Free Hybrid Organic/Inorganic Perovskites Using Metaheuristic-Driven DFT Calculations
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Myoungho Pyo, Byung Do Lee, Jin-Woong Lee, Woon Bae Park, Minseuk Kim, and Kee-Sun Sohn
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Materials science ,Phase stability ,General Chemical Engineering ,Halide ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Lead (geology) ,Chemical engineering ,Organic inorganic ,Materials Chemistry ,0210 nano-technology ,Metaheuristic - Abstract
Hybrid organic/inorganic halide perovskites are considered to be a key material for high-end applications such as photovoltaic and light-emitting devices. Despite the phase stability and toxicity i...
- Published
- 2021
33. Dendrite-free reversible Li plating/stripping in adiponitrile-based electrolytes for high-voltage Li metal batteries
- Author
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Kee-Sun Sohn, Jin-Woong Lee, S. J. Richard Prabakar, Manasi Mwemezi, Myoungho Pyo, Jung Yong Seo, Su Cheol Han, and Woon Bae Park
- Subjects
Nitronium tetrafluoroborate ,Materials science ,Stripping (chemistry) ,Renewable Energy, Sustainability and the Environment ,020209 energy ,02 engineering and technology ,General Chemistry ,Electrolyte ,021001 nanoscience & nanotechnology ,Adiponitrile ,Cathode ,Anode ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Plating ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Dendrite (metal) ,0210 nano-technology - Abstract
The energy densities (EDs) of lithium-ion batteries have improved remarkably mostly via increases in the capacity of cathode materials, which suggests that the next quantum leap will require the simultaneous implementation of high-voltage cathodes and Li metal anodes for high-voltage operations. Herein, we describe for the first time that the compatibility of Li metal in adiponitrile (ADN) is ensured via the utilization of porous Li2O-coated Li (Li/Li2O). The optimal Li2O layer is constructed simply by immersing Li metal in ADN containing nitronium tetrafluoroborate (NO2BF4). When cycled in LiBF4/ADN, porous Li2O facilitates the formation of a stable LiF-enriched interfacial layer, which enables reversible Li plating/stripping during extended cycles with no dendrite formation. The sequential formation of LiF within the pores of Li2O is crucial, because massive formation of LiF precipitates is unavoidable without Li2O. Li/Li2O is also operable in LiTFSI/ADN (TFSI = bis(trifluoromethane)sulfonimide) with the addition of LiBF4. Finally, as a proof-of-concept experiment, we show the charge/discharge behaviors of LiNi0.5Mn1.5O4 when coupled with Li/Li2O in LiBF4:LiTFSI/ADN, which proves that a Li metal cell can be charged to 6.0 V. We hope that this work will expedite the development of Li metal batteries with a high level of ED in the dinitrile family.
- Published
- 2021
34. A study on the bio-applicability of aqueous-dispersed van der Waals 1-D material Nb2Se9 using poloxamer
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Jiho Jeon, Jin Woong Lee, Liyi Shi, Si Young Song, Cong Wang, Kyung Hwan Choi, Zhixiang Liu, Ghulam Asghar, Sung Jae Kim, Sudong Chae, Seungbae Oh, Xue Dong, Jung Heon Lee, Changmo Lim, Jae-Young Choi, Hak Ki Yu, Chaeheon Woo, and Joohoon Kang
- Subjects
Steric effects ,Science ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Dispersant ,Article ,symbols.namesake ,Adsorption ,Copolymer ,Multidisciplinary ,Aqueous solution ,Chemistry ,Synthesis and processing ,Poloxamer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Tissues ,Chemical engineering ,symbols ,Medicine ,van der Waals force ,0210 nano-technology ,Dispersion (chemistry) - Abstract
In this research, dispersion of a new type of one-dimensional inorganic material Nb2Se9, composed of van der Waals bonds, in aqueous solution for bio-application study were studied. To disperse Nb2Se9, which exhibits hydrophobic properties in water, experiments were carried out using a block copolymer (poloxamer) as a dispersant. It was confirmed that PPO, the hydrophobic portion of Poloxamer, was adsorbed onto the surface of Nb2Se9, and PEO, the hydrophilic portion, induced steric hinderance to disperse Nb2Se9 to a size of 10 nm or less. To confirm the adaptability of muscle cells C2C12 to the dispersed Nb2Se9 using poloxamer 188 as dispersant, a MTT assay and a live/dead assay were performed, demonstrating improvement in the viability and proliferation of C2C12 cells.
- Published
- 2021
35. A data-driven XRD analysis protocol for phase identification and phase-fraction prediction of multiphase inorganic compounds
- Author
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Satendra Pal Singh, Kee-Sun Sohn, Jin-Woong Lee, Myoungho Pyo, Minseuk Kim, and Woon Bae Park
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Materials science ,Mean squared error ,business.industry ,Deep learning ,Experimental data ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Convolutional neural network ,Synthetic data ,0104 chemical sciences ,Data-driven ,Inorganic Chemistry ,Identification (information) ,Phase (matter) ,Artificial intelligence ,0210 nano-technology ,Biological system ,business - Abstract
Deep learning (DL) models trained with synthetic XRD data have never accomplished a satisfactory quantitative XRD analysis for the exact prediction of a constituent-phase fraction in unknown multiphase inorganic compounds, although DL-based phase identification has been successful. Here, we report a novel data-driven XRD analysis protocol involving a convolutional neural network (CNN) for exact phase identification and other machine learning (ML) techniques for accurate phase-fraction prediction. A key concept behind this reliable, pragmatic protocol is training with a huge amount of cheap synthetic data and testing with a small amount of expensive real-world experimental data. The protocol was applied to a Li–La–Zr–O quaternary compositional system that involves 218 ICSD-registered inorganic compounds, some of which are known as solid electrolyte materials. Synthetic data-driven XRD analysis has achieved a test accuracy of 96.47% for phase identification and a mean square error (MSE) of 0.0018 and an R2 of 0.9685 for phase-fraction regression. Real-world data tests have led to a phase-identification accuracy of 91.11% and a phase-fraction regression MSE of 0.0024 with an R2 of 0.9587.
- Published
- 2021
36. A data-driven approach to predicting band gap, excitation, and emission energies for Eu2+-activated phosphors
- Author
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Jin-Woong Lee, Minseuk Kim, Satendra Pal Singh, Kee-Sun Sohn, Woon Bae Park, Chaewon Park, and Byung Do Lee
- Subjects
Inorganic Chemistry ,Wavelength ,Materials science ,Band gap ,Activator (phosphor) ,Phosphor ,Excitation ,Computational physics ,Data-driven - Abstract
The prediction of excitation band edge wavelength (EBEW) and peak emission wavelength (PEW) for Eu2+-activated phosphors is intricate in practice, although a theoretical interpretation has been well established. A data-driven approach could be of great help for EBEW and PEW prediction. We collected 91 Eu2+-activated phosphors, the host structures of which exhibit a single activator site and the EBEW and PEW of which are available at the critical activator concentration. We extracted 29 descriptors (input features) that implicate the elemental and structural traits of phosphor hosts, and set up an integrated machine-learning (ML) platform consisting of 18 ML algorithms that allowed prediction of the EBEW and PEW as well as the DFT-calculated band gap (Eg). The acquired dataset involving 91 phosphors was insufficient for the 29-input-feature problem and the real-world data collected from the literature have a so-called dirty nature due to inaccurate, unstandardized experiments. Despite an unavoidable paucity of data and the dirty-data problems of real-world data-based ML implementation, we obtained acceptable holdout dataset test results for PEW predications such as R2 > 0.6, MSE 0.77 for four ML algorithms. The EBEW and Eg predictions returned slightly better test results than these PEW examples.
- Published
- 2021
37. Probabilistic Artificial Neural Network for Line-Edge-Roughness-Induced Random Variation in FinFET
- Author
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Jaehyuk Lim, Changhwan Shin, and Jin Woong Lee
- Subjects
General Computer Science ,Line edge roughness ,Hardware_PERFORMANCEANDRELIABILITY ,01 natural sciences ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,law ,0103 physical sciences ,MOSFET ,Electronic engineering ,Hardware_INTEGRATEDCIRCUITS ,process-induced random variation ,General Materials Science ,Mathematics ,010302 applied physics ,Artificial neural network ,Transistor ,General Engineering ,Probabilistic logic ,Threshold voltage ,TK1-9971 ,machine learning ,FinFET ,Field-effect transistor ,Electrical engineering. Electronics. Nuclear engineering ,Random variable ,030217 neurology & neurosurgery ,artificial neural network ,Voltage - Abstract
Line-edge-roughness (LER) is one of undesirable process-induced random variation sources. LER is mostly occurred in the process of photo-lithography and etching, and it provokes random variation in performance of transistors such as metal oxide semiconductor field effect transistor (MOSFET), fin-shaped field effect transistor (FinFET), and gate-all-around field effect transistor (GAAFET). LER was analyzed/characterized with technology computer-aided design (TCAD), but it is fundamentally very time consuming. To tackle this issue, machine learning (ML)-based method is proposed in this work. LER parameters (i.e., amplitude, and correlation length X, Y) are provided as inputs. Then, artificial neural network (ANN) predicts 7-parameters [i.e., off-state leakage current (Ioff), saturation drain current (Idsat), linear drain current (Idlin), low drain current (Idlo), high drain current (Idhi), saturation threshold voltage (Vtsat), and linear threshold voltage (Vtlin)] which are usually used to evaluate the performance of FinFET. First, how datasets for training process of ANN were generated is explained. Next, the evaluation method for probabilistic problem is introduced. Finally, the architecture of ANN, training process and our new proposition is presented. It turned out that the prediction results (i.e., non-Gaussian distribution of device performance metrics) obtained from the ANN were very similar to that from TCAD in the respect of both qualitative and quantitative comparison.
- Published
- 2021
38. High‐Performance All‐Solid‐State Batteries Enabled by Intimate Interfacial Contact Between the Cathode and Sulfide‐Based Solid Electrolytes
- Author
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Jeongheon Kim, Min Ji Kim, Jaeik Kim, Jin Woong Lee, Joonhyeok Park, Sung Eun Wang, Seungwoo Lee, Yun Chan Kang, Ungyu Paik, Dae Soo Jung, and Taeseup Song
- Subjects
Biomaterials ,Electrochemistry ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Published
- 2023
39. The cut-off value of a qualitative brain diffusion-weighted image (DWI) scoring system to predict poor neurologic outcome in out-of-hospital cardiac arrest (OHCA) patients after target temperature management
- Author
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Insool Yoo, Seung Ryu, In Ho Lee, Changshin Kang, Jin Woong Lee, Yongchul Cho, Yeonho You, Sung Uk Cho, Jung Soo Park, Se Kwang Oh, Jin Hong Min, Changjoo An, Wonjoon Jeong, Hong Joon Ahn, and Seung Whan Kim
- Subjects
medicine.medical_specialty ,Scoring system ,030204 cardiovascular system & hematology ,Emergency Nursing ,Return of spontaneous circulation ,Out of hospital cardiac arrest ,White matter ,03 medical and health sciences ,0302 clinical medicine ,Hypothermia, Induced ,Internal medicine ,medicine ,Humans ,Prospective Studies ,medicine.diagnostic_test ,Receiver operating characteristic ,business.industry ,Cut off value ,Temperature ,Brain ,030208 emergency & critical care medicine ,Magnetic resonance imaging ,Prognosis ,medicine.anatomical_structure ,Emergency Medicine ,Cardiology ,Observational study ,Cardiology and Cardiovascular Medicine ,business ,Out-of-Hospital Cardiac Arrest - Abstract
Aim We presented the cut-off value of a diffusion-weighted image (DWI) scoring system to predict poor neurologic outcome using DWI taken 72−96 h after out-of-hospital cardiac arrest (OHCA) patients underwent target temperature management (TTM). Methods This was a prospective single-centre observational study, conducted from March 2018 to April 2020 in OHCA patients after TTM. Neurological status was assessed 6 months after return of spontaneous circulation (ROSC) using the Glasgow-Pittsburgh cerebral performance categories (CPC) scale. CPC of 1–2 demonstrated good neurologic outcomes whilst a CPC of 3–5 was related to poor neurologic outcomes. The receiver operating characteristic curves and DeLong method were used to evaluate the cut-off value of the DWI scoring system to predict poor neurologic outcome. Results The good and poor neurologic outcome groups consisted of 38 (54.3%) and 32 (45.7%) patients, respectively. The area under the receiver operating characteristic curve (AUROC) of the overall, cortex, deep grey nuclei, and cortex plus deep grey nuclei scores, white matter, brainstem, and cerebellum measured 72−96 h after ROSC were 0.96, 0.96, 0.97, 0.96, 0.95, 0.95, and 0.93 respectively. For 100.0% specificity to predict poor neurologic outcome, the overall scores of the DWI scoring system measured 72−96 h after ROSC with a cut-off value of 52 had a sensitivity of 81.3% (95% CI: 63.6–92.8). Conclusion This study demonstrated that the DWI scoring systems measured between 72 and 96 h after ROSC were valuable tools to predict poor neurologic outcome in post-OHCA patients treated with TTM.
- Published
- 2020
40. Statistical Characterization of the Morphologies of Nanoparticles through Machine Learning Based Electron Microscopy Image Analysis
- Author
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Byoungsang Lee, Yunchul Kim, Junhyuck Chang, Jin Woong Lee, Jae Chul Ro, Jaesub Yun, Jung Heon Lee, Seokyoung Yoon, and Jongmin Lee
- Subjects
False discovery rate ,Materials science ,General Engineering ,General Physics and Astronomy ,Nanoparticle ,Total population ,Image (mathematics) ,Characterization (materials science) ,law.invention ,law ,Transmission electron microscopy ,General Materials Science ,Electron microscope ,Representation (mathematics) ,Biological system - Abstract
Although transmission electron microscopy (TEM) may be one of the most efficient techniques available for studying the morphological characteristics of nanoparticles, analyzing them quantitatively in a statistical manner is exceedingly difficult. Herein, we report a method for mass-throughput analysis of the morphologies of nanoparticles by applying a genetic algorithm to an image analysis technique. The proposed method enables the analysis of over 150,000 nanoparticles with a high precision of 99.75% and a low false discovery rate of 0.25%. Furthermore, we clustered nanoparticles with similar morphological shapes into several groups for diverse statistical analyses. We determined that at least 1,500 nanoparticles are necessary to represent the total population of nanoparticles at a 95% credible interval. In addition, the number of TEM measurements and the average number of nanoparticles in each TEM image should be considered to ensure a satisfactory representation of nanoparticles using TEM images. Moreover, the statistical distribution of polydisperse nanoparticles plays a key role in accurately estimating their optical properties. We expect this method to become a powerful tool and aid in expanding nanoparticle-related research into the statistical domain for use in big data analysis.
- Published
- 2020
41. Flora of the Vascular Plants of the Baekdudaegan Conservation Area in Korean Peninsula(Mil-jae to Myo-jeok-jae) - Including Valley Rivers
- Author
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Kim, jonguk, Hwang, Seung-Hyun, Ahn, Jin-Kap〮〮, JeomSook Lee, and Jin-Woong Lee
- Subjects
geography ,Flora ,geography.geographical_feature_category ,Peninsula ,General Engineering ,General Earth and Planetary Sciences ,Archaeology ,General Environmental Science - Published
- 2020
42. Impact of low and high partial pressure of carbon dioxide on neuron-specific enolase derived from serum and cerebrospinal fluid in patients who underwent targeted temperature management after out-of-hospital cardiac arrest: A retrospective study
- Author
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Seung Ryu, Chan Kang, Sung Uk Cho, Se Kwang Oh, Seung Whan Kim, Byung Kook Lee, Insool Yoo, Yong Chul Cho, Yong Nam In, Hong Joon Ahn, Wonjoon Jeong, Jin Hong Min, Jung Soo Park, Jin Woong Lee, Yeonho You, and Changshin Kang
- Subjects
Male ,inorganic chemicals ,congenital, hereditary, and neonatal diseases and abnormalities ,medicine.medical_specialty ,Partial Pressure ,medicine.medical_treatment ,Enolase ,030204 cardiovascular system & hematology ,Emergency Nursing ,Targeted temperature management ,Return of spontaneous circulation ,Gastroenterology ,Out of hospital cardiac arrest ,03 medical and health sciences ,0302 clinical medicine ,Cerebrospinal fluid ,Hypothermia, Induced ,Internal medicine ,medicine ,Humans ,In patient ,Prospective Studies ,Retrospective Studies ,business.industry ,030208 emergency & critical care medicine ,Retrospective cohort study ,Carbon Dioxide ,respiratory system ,respiratory tract diseases ,Phosphopyruvate Hydratase ,Cohort ,Emergency Medicine ,Cardiology and Cardiovascular Medicine ,business ,Biomarkers ,Out-of-Hospital Cardiac Arrest ,circulatory and respiratory physiology - Abstract
Aim In a previous study, low and high-normal arterial carbon dioxide tension (PaCO2) were not associated with serum neuron-specific enolase (NSE) in cardiac arrest survivors. We assessed the effect of PaCO2 on NSE in cerebrospinal fluid (CSF) and serum. Methods This was a retrospective study. PaCO2 for the first 24 h was analysed in four means, qualitative exposure state (qES), time-weighted average (TWA), median, and minimum–maximum (Min–Max). These subgroups were divided into low (LCO2) and high PaCO2 (HCO2) groups defined as PaCO2 ≤ 35.3 and PaCO2 > 43.5 mmHg, respectively. NSE was measured at 24, 48, and 72 h (sNSE24,48,72 and cNSE24,48,72) from return of spontaneous circulation (ROSC). The primary outcome was the association between PaCO2 and the NSE measured at 24 h after ROSC. Results Forty-two subjects (male, 33; 78.6%) were included in total cohort. PaCO2 in TWA subgroup was associated with cNSE24,48,72, while PaCO2 in the other subgroup were only associated with cNSE24. PaCO2 and cNSE in qES subgroup showed good correlation (r = −0.61; p Conclusion Association was found between NSE and PaCO2 using CSF, despite including normocapnic ranges; TWA of PaCO2 may be most strongly associated with CSF NSE levels. A prospective, multi-centre study is required to confirm our results.
- Published
- 2020
43. Ultra-early neurologic outcome prediction of out-of-hospital cardiac arrest survivors using combined diffusion-weighted imaging findings and quantitative analysis of apparent diffusion coefficient
- Author
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Yeon Ho You, Jung Soo Park, In Sool Yoo, Jin Woong Lee, Won Joon Jeong, Seung Whan Kim, Sung Uk Cho, In Ho Lee, Seung Ryu, Se Kwang Oh, Dong Hun Lee, Chang Shin Kang, Jin Hong Min, Byung Kook Lee, Yong Chul Cho, Dong Hoon Lee, Yong Nam In, and Hong Joon Ahn
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Emergency Nursing ,Targeted temperature management ,Return of spontaneous circulation ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Effective diffusion coefficient ,Survivors ,Retrospective Studies ,Receiver operating characteristic ,business.industry ,030208 emergency & critical care medicine ,Retrospective cohort study ,Prognosis ,Diffusion Magnetic Resonance Imaging ,ROC Curve ,Emergency Medicine ,Radiology ,Cardiology and Cardiovascular Medicine ,business ,Outcome prediction ,Quantitative analysis (chemistry) ,Out-of-Hospital Cardiac Arrest ,Diffusion MRI - Abstract
Aim This study examined whether the presence of cortical necrosis (CN) on ultra-early diffusion-weighted imaging (DWI) and the severity of cytotoxic oedema (CytE) with cerebral oedema (CbrE), measured using quantitative analysis of apparent diffusion coefficient (ADC), could predict neurological outcomes before targeted temperature management in out-of-hospital cardiac arrest survivors (OHCAs). Methods In this retrospective study, the first DWI with ADC scans was performed within 6 h; the second was obtained between 72 and 96 h after return of spontaneous circulation. The primary outcome was neurological outcomes at 6 months after OHCA. The % voxels of ADC value (PV) was calculated; CbrE and CytE values were > or Results Thirty-six patients were included. CN (area under receiver operating characteristic curve [AUC] = 0.800), thld-CytE (PV420; AUC = 0.730), and thld-CbrE (PV1090; AUC = 0.775) showed meaningful performance, and the combined score showed best performance for poor outcome prediction (AUC = 0.956). DWI findings of CN patients was worse at the second DWI. ΔPV significantly increased in the poor outcome group, CN patients, and the group including both, thld-CytE and thld-CbrE. Conclusions In OHCAs, ultra-early DWI with ADC could successfully predict poor neurological outcomes by combining scores of CN, thld-CytE, and thld-CbrE.
- Published
- 2020
44. A deep-learning technique for phase identification in multiphase inorganic compounds using synthetic XRD powder patterns
- Author
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Jin Hee Lee, Satendra Pal Singh, Woon Bae Park, Kee-Sun Sohn, and Jin-Woong Lee
- Subjects
Materials science ,Science ,General Physics and Astronomy ,02 engineering and technology ,Powder xrd ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Phase (matter) ,Computational methods ,lcsh:Science ,Multidisciplinary ,business.industry ,Deep learning ,General Chemistry ,021001 nanoscience & nanotechnology ,X-ray diffraction ,0104 chemical sciences ,Chemical engineering ,lcsh:Q ,Artificial intelligence ,0210 nano-technology ,business ,Inorganic chemistry ,Powder diffraction - Abstract
Here we report a facile, prompt protocol based on deep-learning techniques to sort out intricate phase identification and quantification problems in complex multiphase inorganic compounds. We simulate plausible powder X-ray powder diffraction (XRD) patterns for 170 inorganic compounds in the Sr-Li-Al-O quaternary compositional pool, wherein promising LED phosphors have been recently discovered. Finally, 1,785,405 synthetic XRD patterns are prepared by combinatorically mixing the simulated powder XRD patterns of 170 inorganic compounds. Convolutional neural network (CNN) models are built and eventually trained using this large prepared dataset. The fully trained CNN model promptly and accurately identifies the constituent phases in complex multiphase inorganic compounds. Although the CNN is trained using the simulated XRD data, a test with real experimental XRD data returns an accuracy of nearly 100% for phase identification and 86% for three-step-phase-fraction quantification., Identifying the composition of multiphase inorganic compounds from XRD patterns is challenging. Here the authors use a convolutional neural network to identify phases in unknown multiphase mixed inorganic powder samples with an accuracy of nearly 90%.
- Published
- 2020
45. Aliovalent-doped sodium chromium oxide (Na0.9Cr0.9Sn0.1O2 and Na0.8Cr0.9Sb0.1O2) for sodium-ion battery cathodes with high-voltage characteristics
- Author
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Kee-Sun Sohn, Su Cheol Han, Woon Bae Park, Muthu Gnana Theresa Nathan, Myoungho Pyo, and Jin-Woong Lee
- Subjects
Materials science ,General Chemical Engineering ,Sodium ,Doping ,Analytical chemistry ,Sodium-ion battery ,chemistry.chemical_element ,High voltage ,General Chemistry ,Comproportionation ,Redox ,Cathode ,law.invention ,Ion ,chemistry ,law - Abstract
NaCrO2 with high rate-capability is an attractive cathode material for sodium-ion batteries (NIBs). However, the amount of reversibly extractable Na+ ions is restricted by half, which results in relatively low energy density for practical NIB cathodes. Herein, we describe aliovalent-doped O3–Na0.9[Cr0.9Sn0.1]O2 (NCSnO) and O3–Na0.8[Cr0.9Sb0.1]O2 (NCSbO), both of which show high-voltage characteristics that translate to an increase in energy density. In contrast to NaCrO2, NCSnO and NCSbO can be reversibly charged to 3.80 and 3.95 V, respectively, delivering 0.5 Na+ along with Cr3+/4+ redox alone. The reversible chargeability to Na0.4[Cr0.9Sn0.1]O2 and Na0.3[Cr0.9Sb0.1]O2 is not associated with the suppression of Cr6+ formation. Both compounds show concentrations of Cr6+ that are higher than that of Na0.3CrO2, with an absence of O3′ phases. This implies that aliovalent-doping contributes to a suppression of the Cr6+ migration into tetrahedral sites in the interslab space, which reduces the possibility of irreversible comproportionation. NCSnO and NCSbO deliver capacities comparable to that of NaCrO2, but show a higher average discharge voltage (2.94 V for NaCrO2; 3.14 V for NCSnO; 3.21 V for NCSbO), which leads to a noticeable increase in energy densities. The high-voltage characteristics of NCSnO and NCSbO are also validated via density-functional-theory calculations.
- Published
- 2020
46. Biologically Benign Multi-functional Mesoporous Silica Encapsulated Gold/Silver Nanorods for Anti-bacterial Applications by On-demand Release of Silver Ions
- Author
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Seokyoung Yoon, Jung Heon Lee, Junhyuck Chang, Jeon G. Han, Younghwan Chung, and Jin Woong Lee
- Subjects
Biocompatibility ,Chemistry ,Biomedical Engineering ,Nanoparticle ,Bioengineering ,engineering.material ,Mesoporous silica ,Coating ,engineering ,Electrical and Electronic Engineering ,Surface plasmon resonance ,Cytotoxicity ,Bimetallic strip ,Biotechnology ,Nuclear chemistry ,Antibacterial agent - Abstract
Although silver (Ag)-based nanoparticles (NPs) are frequently used for bactericidal purposes, they have critical issues including excessive release of Ag+, severe oxidation, and cytotoxicity. In this study, we designed a multifunctional, on-demand antibacterial agent by successively encapsulating bimetallic gold/silver nanorods (Ag/AgNRs) with mesoporous silica (mSiO2) shells. Au/AuNRs were synthesized by coating Ag on AuNRs in a controlled manner, so that they exhibited a localized surface plasmon resonance peak in the near-infrared (NIR) region. When Au/AgNR@mSiO2 NPs were irradiated with an NIR laser under optimal conditions (0.4 W/cm2), they generated a small amount of heat (40–45 oC), which successively triggered the release of Ag+ and induced bacterial cell death. Here, mSiO2 shells play critical roles because they not only protect Ag from oxidation but also prevent the burst release of Ag+ and improve biocompatibility of the antibacterial agent against normal cells. We found that this multifunctional bacterial agent effectively kills gram-negative Escherichia coli and gram-positive Staphylococcus aureus without significantly increasing the temperature of the medium. Au/AgNR@mSiO2 NPs were also biologically benign with high biocompatibility against mammalian cells.
- Published
- 2019
47. Significant Enhancement of the Adhesion Properties of Chemically Functionalized Polypropylene
- Author
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Jung Heon Lee, Jin Woong Lee, Jun Hyuk Heo, Hui Hun Cho, and Byoungsang Lee
- Subjects
Polypropylene ,chemistry.chemical_compound ,Materials science ,Chemical engineering ,chemistry ,General Materials Science ,Adhesion - Abstract
Organosilicon compounds have been actively used with nano- and micro-fillers to improve the adhesion and mechanical properties. However, studies on the adhesion properties of polymeric materials, such as polypropylene (PP), functionalized with organosilicon compounds are limited. Here, we investigated the adhesion of organosilanized PP substrates, functionalized using (3-glycidoxypropyl)trimethoxysilane (GPTMS) and (3-aminopropyl)trimethoxysilane (APTMS) as coupling agents, with epoxy adhesives. The curing of epoxy-functionalized PP (PP-EPOXY) with triethylenetetramine (TETA) hardener led to the chemical crosslinking of TETA with PP-EPOXY, as determined by X-ray photoelectron spectroscopy and vacuum Fourier-transform infrared spectroscopy. Similarly, the curing of amine-functionalized PP (PP-NH2) with bisphenol A diglycidyl ether (DGEBA) epoxy resin led to the chemical crosslinking of the resin with PP-NH2. Finally, we measured the adhesion properties of the functionalized PP substrates using an adhesive composed of DGEBA and TETA based on ASTM D3163 and observed that the shear strength of PP-EPOXY and PP-NH2 increased significantly up to 580% and 506% as compared with that of bare PP. These results strongly suggest that the functionalization of PP significantly contributes to the improvement of adhesion with an adhesive.
- Published
- 2019
48. Relationship between optic nerve sheath diameter measured by magnetic resonance imaging, intracranial pressure, and neurological outcome in cardiac arrest survivors who underwent targeted temperature management
- Author
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In Ho Lee, Jin Woong Lee, Seung Ryu, Sung Uk Cho, Dong Hun Lee, Byung Kook Lee, Yeonho You, Se Kwang Oh, Jin Hong Min, Changshin Kang, Jung Soo Park, Hong Joon Ahn, Minjung Kathy Chae, Wonjoon Jeong, Insool Yoo, Seung Whan Kim, and Yong Chul Cho
- Subjects
Adult ,Male ,Intracranial Pressure ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Emergency Nursing ,Targeted temperature management ,03 medical and health sciences ,0302 clinical medicine ,Lumbar ,Hypothermia, Induced ,Interquartile range ,Humans ,Medicine ,Aged ,Retrospective Studies ,Intracranial pressure ,Aged, 80 and over ,medicine.diagnostic_test ,business.industry ,Optic Nerve ,030208 emergency & critical care medicine ,Retrospective cohort study ,Magnetic resonance imaging ,Middle Aged ,Magnetic Resonance Imaging ,humanities ,Catheter ,ROC Curve ,Anesthesia ,Emergency Medicine ,Optic nerve ,Female ,Cardiology and Cardiovascular Medicine ,business ,Out-of-Hospital Cardiac Arrest - Abstract
Studies on the prognostic performance of optic nerve sheath diameter (ONSD) in out-of-hospital cardiac arrest survivors (OHCA) have reported conflicting results. We aimed to investigate the usefulness of ONSD measured using magnetic resonance imaging (MRI) to estimate its association with intracranial pressure (ICP) and 6-month neurological outcomes in CA survivors treated with targeted temperature management (TTM).This retrospective study included 37 CA survivors who underwent TTM from January 2018 to December 2018. ICP was measured by lumbar catheter during TTM on Days 0, 1, 2, and 3. ONSD was measured using MRI on Days 0 and 3. The primary outcome was the correlation between ONSD and ICP associated with neurological outcomes obtained after 6 months.The median (interquartile range [IQR]) ONSD was not significantly different between the good and poor neurological outcome group on Day 0 (5.2 mm [4.8-5.8] vs 5.2 mm [4.8-5.6]; p = 0.948) and Day 3 (5.0 mm [4.8-5.2] vs 5.5 mm [4.4-5.9]; p = 0.105). ONSD and ICP had excellent correlation on Day 3 (r = 0.90, p 0.001). ONSD showed excellent correlation with increased ICP (IICP) defined as ICP above 20 mmHg (r = 0.89, p 0.001). ONSD cut-off of 5.99 mm was used with a sensitivity of 90.0% and specificity of 98.0% to identify IICP.The ONSD on Days 0 or 3 did not show differences in neurological outcomes in OHCA patients treated with TTM. However, ONSD had an excellent correlation with ICP on Day 3 and with IICP. Further studies are required to confirm our results.
- Published
- 2019
49. Optimal timing to measure optic nerve sheath diameter as a prognostic predictor in post-cardiac arrest patients treated with targeted temperature management
- Author
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In Ho Lee, Wonjoon Jeong, Junwan Lee, Insool Yoo, Se Kwang Oh, Jin Hong Min, Jung Soo Park, Jin Woong Lee, Yeonho You, Changshin Kang, Yongchul Cho, Sung Uk Cho, Seung Whan Kim, Hong Joon Ahn, and Seung Ryu
- Subjects
medicine.medical_specialty ,Optic nerve sheath ,Receiver operating characteristic ,business.industry ,medicine.medical_treatment ,030208 emergency & critical care medicine ,030204 cardiovascular system & hematology ,Emergency Nursing ,Targeted temperature management ,Return of spontaneous circulation ,Confidence interval ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Emergency Medicine ,medicine ,Cardiology ,Optic nerve ,Observational study ,Post cardiac arrest ,Cardiology and Cardiovascular Medicine ,business - Abstract
Aim We evaluated the optimal timing of optic nerve sheath diameter (ONSD) measurement to predict neurologic outcome in post-cardiac arrest patients treated with target temperature management (TTM). Methods This was a prospective single-centre observational study from April 2018 to March 2019. Good outcome was defined as the Glasgow-Pittsburgh cerebral performance categories (CPC) 1 or 2, and poor outcome as a CPC between 3 and 5. ONSD was measured initially after return of spontaneous circulation (ROSC) (ONSDinitial), at 24 h (ONSD24), 48 h (ONSD48), and 72 h (ONSD72) using ultrasonography. The receiver operating characteristic (ROC) curves and DeLong method were used to compare the values for predicting neurologic outcomes. Results Out of the 36 patients enrolled, 18 had a good outcome. ONSD24, ONSD48, and ONSD72 were higher in the poor outcome group. The area under ROC curve of ONSD24 was 0.91 (95% confidence interval 0.77–0.98) in predicting poor neurologic outcomes. With a cut off value of 4.90 mm, ONSD24 had a sensitivity of 83.3% and a specificity of 94.4% in predicting poor neurologic outcomes. Conclusion Our findings demonstrate ONSD24 as a valuable tool to predict the neurologic outcome in post-cardiac arrest patients treated with TTM. Therefore, we recommend performing ONSD measurement using ultrasonography at 24 h after ROSC, rather than immediately after ROSC, to predict neurologic outcome in post-cardiac arrest patients treated with TTM.
- Published
- 2019
50. A novel sulfide phosphor, BaNaAlS3:Eu2+, discovered via particle swarm optimization
- Author
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Joonseo Park, Jin-Woong Lee, Satendra Pal Singh, Minseuk Kim, Byung Do Lee, Kee-Sun Sohn, and Woon Bae Park
- Subjects
History ,Polymers and Plastics ,Mechanics of Materials ,Mechanical Engineering ,Materials Chemistry ,Metals and Alloys ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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