189 results on '"Seokwon Lee"'
Search Results
52. Survival of women with pregnancy-associated breast cancer according to clinical characteristics: A propensity score matching study
- Author
-
Hongki Gwak, Sang Seok Woo, Eun-Sook Lee, Min Ho Park, Seokwon Lee, Hyun Jo Youn, Seho Park, In Suck Suh, and Seong Hwan Kim
- Subjects
Ki-67 Antigen ,Pregnancy ,Humans ,Breast Neoplasms ,Female ,Triple Negative Breast Neoplasms ,General Medicine ,Neoplasm Recurrence, Local ,Prognosis ,Propensity Score ,Pregnancy Complications, Neoplastic ,Retrospective Studies - Abstract
In recent years, postponing childbearing has increased the prevalence of pregnancy-associated breast cancer (PABC). PABC has a poorer prognosis than breast cancer not associated with pregnancy (non-PABC) due to delayed diagnosis and aggressive subtype. Additionally, pregnancy itself predicts a poor prognosis; but, this is a subject of debate. Thus, we analyzed the effects of known prognostic factors and pregnancy on the prognosis of PABC. We retrospectively analyzed women aged 20 to 49 years who were diagnosed with breast cancer (BC) between 1989 and 2014. Patients were distributed into PABC and non-PABC groups, and 1:4 propensity score matching was performed to adjust for baseline characteristics. Primary endpoints were overall survival (OS) and BC-specific survival (BCSS). Secondary endpoint was the difference in prognosis according to BC subtype. Of the 34,970 recruited patients with BC, 410 (1.2%) had PABC. Patients with PABC were younger and tended to have triple-negative BC (TNBC) subtype than non-PABC patients. The 1640 matched non-PABC patients showed a significantly worse mean survival rate than the unmatched non-PABC patients. Patients with PABC had a significantly worse OS and BCSS than those with non-PABC. In multivariate analyses, patients with PABC of luminal B (Ki-67 ≥14.0%) and TNBC subtypes had worse OS and BCSS than patients with non-PABC. Patients with PABC had poorer prognosis than non-PABC patients after adjusting for several prognostic factors. This difference was particularly significant in patients with the luminal B and TNBC subtypes.
- Published
- 2022
53. Non-handover Based Mobility Management in Hierarchically Structured Cellular Networks.
- Author
-
Hyungsik Ju, Seokwon Lee, Daesik Hong, Kiyoung Han, and Jaeho Jeon
- Published
- 2010
- Full Text
- View/download PDF
54. Development of bio-mimetic robot hand using parallel mechanisms.
- Author
-
Seokwon Lee, Samyeul Noh, Yongkwun Lee, and Jong Hyeon Park
- Published
- 2009
- Full Text
- View/download PDF
55. Omission of chemotherapy for hormone receptor-positive and human epidermal growth factor receptor 2-negative breast cancer: patterns of treatment and outcomes from the Korean Breast Cancer Society Registry
- Author
-
Hannah Lois, Kangleon-Tan, Jongmin, Sim, Ji Young, You, Eun-Shin, Lee, Haemin, Lee, Sun Moon, Yang, Min-Ki, Seong, Eun Hwa, Park, Seok Jin, Nam, Min Ho, Park, Seokwon, Lee, Woo-Chan, Park, Rogelio G, Kangleon, Crisostomo B, Dy, Soo Youn, Bae, and Seung Pil, Jung
- Subjects
Surgery - Abstract
Although adjuvant chemotherapy (CTx) is still recommended for high-risk patients with hormone receptor-positive and human epidermal receptor (HER)-2-negative breast cancer, recent studies found that selected patients with low disease burden may be spared from CTx and receive hormonal treatment (HT) alone. This study aims to evaluate the trends of treatment (CTx + HTThe Korean Breast Cancer Society Registry was queried (2000 to 2018) for women with pT1-2N0-1 hormone receptor-positive and HER2-negative disease who underwent surgery and adjuvant systemic treatment (CTx and HT). Clinicopathologic factors, change in pattern of treatment over time, and OS for each treatment option were analyzed.A total of 40,938 women were included in the study; 20,880 (51.0%) received CTx + HT, while 20,058 (49.0%) received HT only. In recent years, there has been a steady increase in the use of HT alone, from 21.0% (2000) to 64.6% (2018). In Cox regression analysis, age, type of breast and axillary operations, T and N stages, body mass index, histologic grade, and presence of lymphovascular invasion were prognostic indicators for OS. There was no significant difference between CTx + HT and HT alone in terms of OS (P = 0.126).Over the years, there has been a shift from CTx + HT to HT alone without a significant difference in OS. Therefore, HT alone could be a safe treatment option in selected patients, even those with T2N1 disease.
- Published
- 2022
56. Adhesion and Stability Increased Carbon Nanowall for the Application to Lithium-Ion Batteries
- Author
-
May Tran Thi, Seokwon Lee, and Wonseok Choi
- Subjects
Electrical and Electronic Engineering - Published
- 2022
- Full Text
- View/download PDF
57. Abstract 1772: Development of a novel L1CAM-targeted CAR-T, CX804, and its therapeutic efficacy in ovarian and gastric cancer
- Author
-
Xiumei Che, Un-Jung Yun, Seokwon Lee, Youngyoub Kim, Junshub Lee, Jina Chae, Jehee Suh, Eun-Ji Nam, Gun Min Kim, Hyoyoung Kim, and Minkyu Jung
- Subjects
Cancer Research ,Oncology - Abstract
L1 cell adhesion molecule (L1CAM) is involved in cancer development and aberrantly expressed in various tumor. It is also associated with aggressive progression, metastasis, and poor prognosis. Public database, a Kaplan-Meier plotter (http://www.kmplot.com) shows that L1CAM high-expression significantly reduced survival of ovarian and gastric cancer patients. We developed a novel chimeric antigen receptor (CAR)-T cell targeted to L1CAM. A novel scFV candidate (Clone H8) to L1CAM was obtained by bio-panning of phage displaying human synthetic scFv fragments to human and mouse L1CAM proteins. H8 scFV was linked to IgD-IgG1 hinge, CD28 transmembrane domain, CD28 and ICOS co-stimulation domain, and CD3ζ domain, resulting in CX804 CAR-T. The efficacy of L1CAM CAR-T cells, CX804 showed correlation with the level of L1CAM in human ovarian and gastric cancer cells. CX804 exerted cytotoxicity toward 293T cells expressing human or mouse L1CAM protein. CX804 also reacted with L1CAM-positive ovarian SKOV3 cancer cell and gastric MKN-28 and AGS cancer cells and secreted T-cell activation cytokines, IFN-γ and TNF-α, in response to these cells. However, CX804 rarely lysed L1CAM-negative normal 293 cells and SNU-719 gastric cancer cells. Furthermore, L1CAM CAR-T cells dramatically lysed high L1CAM expressing patient derived cell (PDC) of gastric cancer compared with low L1CAM expressing PDC cell. Xenograft model of ovarian cancer was developed by intraperitoneal (IP) injecting SKOV3-Fluc cells into NOD/SCID or NSG mice. CAR-T cells were administrated via intravenous (IV) or IP route on 5 days after tumor inoculation. Administration of CX804 significantly decreased tumor burden and increased survival in mouse model of ovarian cancer. Route of administration significantly affected bio-distribution and antitumor effect of CX804 where antitumor activity of CX804 was only observed when CX804 were given IP, but not the IV route. Taken together, our results suggest that CX804 exerts potent and specific effect against L1CAM positive cancer cells in vitro and in vivo. Furthermore, we propose that newly established CAR-T cells targeting L1CAM facilitate therapy against L1CAM-positive ovarian and gastric cancer patients Citation Format: Xiumei Che, Un-Jung Yun, Seokwon Lee, Youngyoub Kim, Junshub Lee, Jina Chae, Jehee Suh, Eun-Ji Nam, Gun Min Kim, Hyoyoung Kim, Minkyu Jung. Development of a novel L1CAM-targeted CAR-T, CX804, and its therapeutic efficacy in ovarian and gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1772.
- Published
- 2023
- Full Text
- View/download PDF
58. Is mastectomy with immediate reconstruction safe for patients undergoing neoadjuvant chemotherapy? A nationwide study from Korean Breast Cancer Society
- Author
-
Hyun-Ah Kim, Young-Joo Lee, Sungmin Park, Young Jin Choi, Jiyoung Kim, Soo Youn Bae, Wonshik Han, Joon Jeong, Kyung Do Byun, and Seokwon Lee
- Subjects
Adult ,0301 basic medicine ,medicine.medical_specialty ,Mammaplasty ,medicine.medical_treatment ,Breast Neoplasms ,Mastectomy, Segmental ,Disease-Free Survival ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Surgical oncology ,Republic of Korea ,medicine ,Humans ,Pharmacology (medical) ,Radiology, Nuclear Medicine and imaging ,Stage (cooking) ,Survival analysis ,Aged ,Proportional Hazards Models ,Retrospective Studies ,Aged, 80 and over ,Chemotherapy ,business.industry ,Retrospective cohort study ,General Medicine ,Middle Aged ,medicine.disease ,Combined Modality Therapy ,Neoadjuvant Therapy ,Surgery ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,Female ,business ,Breast reconstruction ,Mastectomy - Abstract
In this study, we compared the prognoses of patients who underwent mastectomy with immediate breast reconstruction (IBR) after neoadjuvant chemotherapy with those who underwent mastectomy. This retrospective study included 87,995 patients who were surgically treated for primary breast cancer between 2008 and 2014. We compared the three groups of patients who were divided based on the following surgeries: breast-conserving surgery (BCS), mastectomy, and mastectomy with IBR. Of the 3295 patients who were treated with neoadjuvant chemotherapy, 482 patients achieved a pathological complete response (pCR) and 2813 patients did not (non-pCR). In survival analysis of the pCR patients, the 5-year Overall Survival (5 yr OS) between those who underwent mastectomy with IBR and mastectomy (P = 0.639) In the non-pCR group, 5 yr OS of the mastectomy with IBR group was 90.0%, while those of the mastectomy group was 84.4% in patients with clinical stage II (P = 0.032). In a multivariate analysis by Cox regression method revealed that the prognoses of the patients who underwent mastectomy with IBR were not different from those of patients who underwent mastectomy group in both groups (the pCR group and the non-pCR group). In the pCR group, the prognoses of patients who underwent mastectomy with IBR were not different from those of patients who underwent mastectomy. In the non-pCR group, women in the mastectomy with IBR group had shown worse prognoses than the mastectomy group in advanced clinical stage. Appropriate operation should be determined depending on the status of individualized patients.
- Published
- 2021
- Full Text
- View/download PDF
59. Robust-Backstepping Missile Autopilot Design Considering Time-Varying Parameters and Uncertainty
- Author
-
Gwanyoung Moon, Seokwon Lee, Byung-Eul Jeon, Yongwoo Lee, and Youdan Kim
- Subjects
020301 aerospace & aeronautics ,Computer science ,Aerospace Engineering ,02 engineering and technology ,Aerodynamics ,Nonlinear system ,Acceleration ,Missile ,0203 mechanical engineering ,Computer Science::Systems and Control ,Linearization ,Control theory ,Backstepping ,Electrical and Electronic Engineering ,Parametric statistics - Abstract
Missile autopilots for aerodynamic angle control and acceleration control are designed for fin-controlled missiles during the boost phase. In the boost phase, the speed change and the parameter variation of the missile are fast and large. To deal with the time-varying characteristics of the missile, the time-varying parameters are considered in nonlinear dynamics, and the parametric uncertainties are modeled. A state-feedback controller is designed for aerodynamic angle control based on a robust-backstepping scheme. Also, an output feedback controller is designed for acceleration control, where the acceleration dynamics are derived using input–output linearization. Numerical simulations are performed to demonstrate the performance of the proposed controllers.
- Published
- 2020
- Full Text
- View/download PDF
60. Study of reliable via structure for Fan Out Panel Level Package (FoPLP)
- Author
-
Da-Hee Kim, Jae-Ean Lee, Gyujin Choi, Sunguk Lee, Giho Jeong, Hongwon Kim, Seokwon Lee, and Dong Wook Kim
- Published
- 2022
- Full Text
- View/download PDF
61. 5-Thiaporphyrinium cation: effect of sulphur incorporation on excited state dynamics
- Author
-
Asahi Takiguchi, Naoto Inai, Seongsoo Kang, Masaya Hagai, Seokwon Lee, Takeshi Yanai, Dongho Kim, and Hiroshi Shinokubo
- Subjects
Cations ,Materials Chemistry ,Metals and Alloys ,Ceramics and Composites ,Quantum Theory ,General Chemistry ,Vibration ,Catalysis ,Fluorescence ,Sulfur ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
We synthesised thionium-ion embedded aromatic porphyrinoids: a free-base 5-thiaporphyrinium cation and its zinc complex. The sulphur atom effectively participates in the macrocyclic π-conjugation. Fluorescence quantum yields of thiaporphyrinium cations were lower than 1% unlike oxaporphyrinium cations. Detailed photophysical analysis and DFT calculations clarified the vibrational mode regarding the out-of-plane motion of the sulphur atom induced ultrafast quenching of the excited state in comparison to the corresponding oxaporphyrinium cations.
- Published
- 2022
62. Analysis of the Properties of Tungsten Carbide Thin Films According to the Sputtering Radio Frequency Power
- Author
-
Young Suk Park, Seokwon Lee, Won Seok Choi, and Jung-Hyun Kim
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Tungsten carbide ,business.industry ,Sputtering ,Optoelectronics ,General Materials Science ,Thin film ,business ,Radio frequency power transmission - Abstract
In this study, we investigated characteristics of tungsten carbide thin film according to carbon and tungsten ratio. Tungsten carbide thin film was co-sputtered on silicon substrate and glass substrates using an RF magnetron sputtering system. To analyze the characteristics according to the composition ratio of the tungsten carbide thin film, the RF powers of carbon/tungsten target were divided into 100 W/100 W, 125 W/75 W, 150 W/50 W, and 175 W/25 W, respectively. Hall measurement and 4 points probes were used to measure electrical properties of the tungsten carbide thin films. Raman and field emission scanning electron microscope (FE-SEM) analysis were performed.
- Published
- 2020
- Full Text
- View/download PDF
63. Midcourse Guidance for Exoatmospheric Interception Using Response Surface Based Trajectory Shaping
- Author
-
Jaemyung Ahn, Youdan Kim, Sungjun Ann, and Seokwon Lee
- Subjects
020301 aerospace & aeronautics ,Computer science ,Ballistic missile ,Aerospace Engineering ,Thrust ,02 engineering and technology ,Missile ,0203 mechanical engineering ,Position (vector) ,Control theory ,Trajectory ,Point (geometry) ,Electrical and Electronic Engineering ,Interception - Abstract
An exoatmospheric midcourse guidance law is proposed to intercept a ballistic missile during the free-flight phase. The proposed guidance law generates a thrust direction command for an antiballistic missile to hit the target at the predicted intercept point. For the predicted intercept point, the zero-effort-miss and zero-effort-velocity are determined based on the solutions of the two-body orbital boundary/initial value problems. The intercept point is predicted by using the trajectory shaping parameter that combines the zero effort trajectory and minimum time trajectory. A response surface model for the minimum interception time is constructed as a database, which is the polynomial function of the initial condition. The response surface model provides a predicted minimum time interception position for the midcourse guidance. Case studies are performed to demonstrate the performance of the proposed guidance law considering various uncertainties.
- Published
- 2020
- Full Text
- View/download PDF
64. Impact-Time-Control Guidance Strategy with a Composite Structure Considering the Seeker’s Field-of-View Constraint
- Author
-
Seokwon Lee, Namhoon Cho, and Youdan Kim
- Subjects
Space and Planetary Science ,Control and Systems Engineering ,Applied Mathematics ,Aerospace Engineering ,Electrical and Electronic Engineering - Published
- 2020
- Full Text
- View/download PDF
65. MiSeAlimi: Application Providing Individual Fine Dust Intake Information according to Movement Path
- Author
-
Seokwon Lee, Kyeonghun Park, and Hyungwon Lee
- Subjects
Computer science ,Movement (music) ,Path (graph theory) ,Real-time computing ,Air quality index - Published
- 2020
- Full Text
- View/download PDF
66. What predicts better prognosis in elderly breast cancer patients?
- Author
-
Seungju Lee, Choongrak Kim, Hyun-June Paik, Chang Shin Jung, Hyun Yul Kim, Youn Joo Jung, Jee Yeon Kim, Hyuk Jae Jung, and Seokwon Lee
- Subjects
Oncology ,medicine.medical_specialty ,Breast cancer ,business.industry ,Internal medicine ,medicine ,medicine.disease ,business - Published
- 2020
- Full Text
- View/download PDF
67. Nipple-sparing mastectomy for breast cancer close to the nipple: a single institution’s 11-year experience
- Author
-
Youngtae Bae, Seungju Lee, Seokwon Lee, and Sunhyun Kim
- Subjects
Adult ,0301 basic medicine ,Nipple-Sparing Mastectomy ,medicine.medical_specialty ,Mastectomy, Subcutaneous ,Breast Neoplasms ,Kaplan-Meier Estimate ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Surgical oncology ,medicine ,Humans ,Pharmacology (medical) ,Radiology, Nuclear Medicine and imaging ,Single institution ,Retrospective Studies ,Tumor size ,business.industry ,General Medicine ,Middle Aged ,University hospital ,medicine.disease ,Surgery ,Survival Rate ,Carcinoma, Intraductal, Noninfiltrating ,Treatment Outcome ,030104 developmental biology ,Oncology ,Nipples ,030220 oncology & carcinogenesis ,Female ,Neoplasm Recurrence, Local ,business ,Breast reconstruction ,Follow-Up Studies ,Preoperative imaging - Abstract
This study aimed to analyze our 11-year experience using NSM with immediate breast reconstruction in breast cancer. Between January 2007 and December 2015, 251 NSMs were performed on 251 women with breast cancer for therapeutic purpose at Pusan National University Hospital. The clinical and pathologic mean tumor size was 3.1 cm. Based on preoperative imaging, mean distance between tumor and nipple was 2.5 cm. Among 251 tumors, 119 cases (47.4%) and 69 cases (27.5%) with a distances ≤ 2 cm and ≤ 1 cm, respectively, were detected. There were 11 patients (4.4%) with locoregional recurrences during the mean follow-up period of 68.0 months. Of these 11 cases, one (0.4%) had local recurrence in the retained NAC, and the others had recurrence in the chest wall or skin. Unless clinical and histological evidence of nipple involvement, NSM can be an oncologically safe surgical option for breast cancer, even if the tumor is located close to the nipple.
- Published
- 2020
- Full Text
- View/download PDF
68. Capturability of Impact-Angle Control Composite Guidance Law Considering Field-of-View Limit
- Author
-
Seokwon Lee and Youdan Kim
- Subjects
Acceleration ,Missile ,Pursuit guidance ,Computer science ,Law ,Trajectory ,Aerospace Engineering ,Proportional navigation ,Field of view ,Limit (mathematics) ,Electrical and Electronic Engineering ,Collision - Abstract
A capture region of the composite guidance law is analyzed for a missile equipped with a strapdown seeker. The composite guidance law consists of a deviated pure pursuit guidance law and a pure proportional navigation guidance law to perform impact-angle control. The range of the field-of-view limit restricts the performance of the guidance law, which reduces the capture region. Based on the characteristics of the guidance law, the range of the achievable impact angle is investigated by considering the collision condition and the field-of-view limit. It is shown that the capture region is represented in terms of the relative initial position and terminal flight-path angle. Numerical simulations are performed to investigate the properties of the proposed capture region of the composite guidance law.
- Published
- 2020
- Full Text
- View/download PDF
69. The Effects of Internal Employability, External Employability on Turnover Intention : Focused on the Moderating Effects of Social Exchange Relationship
- Author
-
Seokwon Lee and Hack-Soo Kim
- Subjects
Social exchange theory ,Turnover intention ,Employability ,Psychology ,Social psychology - Published
- 2020
- Full Text
- View/download PDF
70. Reactive Collision Avoidance Algorithm for UAV Using Bounding Tube Against Multiple Moving Obstacles
- Author
-
Namhoon Cho, Jong-Ho Park, and Seokwon Lee
- Subjects
dynamic environment ,Aiming point ,General Computer Science ,Computer science ,multiple obstacles ,General Engineering ,Kalman filter ,guidance algorithm ,Collision ,Computer Science::Robotics ,Vehicle dynamics ,Bounding overwatch ,Minimum bounding box ,Obstacle ,unmanned aerial vehicle ,Reactive collision avoidance ,General Materials Science ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:TK1-9971 ,Algorithm ,Collision avoidance - Abstract
A reactive collision avoidance algorithm is proposed to enable safe autonomous flight in the presence of multiple dynamic obstacles. A position-controlled hexacopter equipped with a visual sensor obtaining obstacle information is considered as an Unmanned Aerial Vehicle (UAV) platform. The proposed method centers on the concept of bounding tube which intrinsically extends the static bounding box to incorporate forthcoming movement of the obstacles into the collision avoidance framework. The processing pipeline consists of separate components for each of the sequential tasks in obstacle sensing and tracking. Computation of a spherical bounding box for each obstacle is followed by discrete-time Kalman filtering for prediction of obstacle trajectory to detect potential collision. If the current course of UAV turns out highly likely to end in collision with any of the obstacles, the vehicle steers to an aiming point chosen from among the bundle of candidates produced by constructing a bounding tube that takes account of predicted obstacle motion. The bounding-tube-based aiming point generation extends seamlessly to the case with multiple moving obstacles through running in series with multi-obstacle track management that combines hierarchical clustering of sensory data points for obstacle identification and a simple geometric method for data association. Numerical simulations are conducted to verify the performance of the proposed collision avoidance algorithm.
- Published
- 2020
- Full Text
- View/download PDF
71. Analysis of rendezvous guidance laws for autonomous aerial refueling for non-maneuvering and identical speed targets
- Author
-
Seokwon Lee and Mingu Kim
- Subjects
Air-to-Air Refueling ,Deviated Pursuit Guidance ,Proportional Navigation Guidance ,Aerospace Engineering ,Rendezvous Guidance - Abstract
This study analyzes rendezvous guidance schemes for UAVs refueling. Assuming the target is non-maneuvering with identical speed, a necessary condition is investigated for the UAV to approach the rendezvous point. Three types of guidance laws are considered to analyze the performance under the condition. A reachable region is analytically obtained using the closed-form solution of the deviated pursuit and pure proportional navigation. Numerical simulation demonstrates the analyzed result for the rendezvous mission.
- Published
- 2022
72. Total quilting suture at latissimus dorsi muscle donor site: Drain tube is no longer needed
- Author
-
Youngtae Bae, Seokwon Lee, Younjung Cha, Younglae Jung, and Jungbum Choi
- Subjects
medicine.medical_specialty ,business.industry ,Drain tube ,medicine.medical_treatment ,Latissimus dorsi muscle ,medicine.disease ,Latissimus dorsi myocutaneous flap ,Surgery ,Suture (anatomy) ,Seroma ,Mammaplasty ,Medicine ,business ,Quilting - Published
- 2019
- Full Text
- View/download PDF
73. Preparation of Carbon Nanowall and Carbon Nanotube for Anode Material of Lithium-Ion Battery
- Author
-
Jang Myoun Ko, Won Seok Choi, Hyunil Kang, Seokhun Kwon, Kangmin Kim, and Seokwon Lee
- Subjects
Battery (electricity) ,Materials science ,PECVD ,Pharmaceutical Science ,chemistry.chemical_element ,Carbon nanotube ,lithium-ion battery ,Lithium-ion battery ,Article ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,QD241-441 ,carbon nanowall ,law ,Drug Discovery ,FE-SEM ,Physical and Theoretical Chemistry ,carbon nanotube ,Organic Chemistry ,Lithium hexafluorophosphate ,cyclic voltammetry ,Anode ,Field emission microscopy ,chemistry ,Chemical engineering ,Chemistry (miscellaneous) ,Molecular Medicine ,Cyclic voltammetry ,Carbon - Abstract
Carbon nanowall (CNW) and carbon nanotube (CNT) were prepared as anode materials of lithium-ion batteries. To fabricate a lithium-ion battery, copper (Cu) foil was cleaned using an ultrasonic cleaner in a solvent such as trichloroethylene (TCE) and used as a substrate. CNW and CNT were synthesized on Cu foil using plasma-enhanced chemical vapor deposition (PECVD) and water dispersion, respectively. CNW and CNT were used as anode materials for the lithium-ion battery, while lithium hexafluorophosphate (LiPF6) was used as an electrolyte to fabricate another lithium-ion battery. For the structural analysis of CNW and CNT, field emission scanning electron microscope (FE-SEM) and Raman spectroscopy analysis were performed. The Raman analysis showed that the carbon nanotube in composite material can compensate for the defects of the carbon nanowall. Cyclic voltammetry (CV) was employed for the electrochemical properties of lithium-ion batteries, fabricated by CNW and CNT, respectively. The specific capacity of CNW and CNT were calculated as 62.4 mAh/g and 49.54 mAh/g. The composite material with CNW and CNT having a specific capacity measured at 64.94 mAh/g, delivered the optimal performance.
- Published
- 2021
- Full Text
- View/download PDF
74. Characteristics of Functional Film Synthesized on the Cover Glass of Photovoltaic Modules
- Author
-
Seung-cheol Yoo, Jung-Hyun Kim, Chang Yeon Lee, Won Seok Choi, Yeon-Ho Joung, Young Suk Park, Chulsoo Kim, and Seokwon Lee
- Subjects
Technology ,Control and Optimization ,Materials science ,Energy Engineering and Power Technology ,anti-pollution ,engineering.material ,Indentation hardness ,Paint adhesion testing ,photovoltaics module ,Contact angle ,Coating ,hot-air annealing ,Transmittance ,bar coating ,Electrical and Electronic Engineering ,Composite material ,Engineering (miscellaneous) ,Renewable Energy, Sustainability and the Environment ,Photovoltaic system ,Adhesion ,Cover glass ,engineering ,functional film ,Energy (miscellaneous) - Abstract
In this study, the characteristics of functional films were investigated according to the number of coatings and their heat treatment times. The functional coating films were deposited on glass substrates made of the same material as the cover glass of photovoltaic (PV) modules. Each film was coated once by brushing with a special silica-based solution, and each heat treatment was done using a hot-air fan for 2 min at 300 °C. The substrates were coated once, twice, and thrice, respectively, and were annealed once, twice, and thrice by drying and cooling alternately. The specimens were then analyzed for their anti-pollution properties, contact angles, light transmittance, and mechanical properties. The anti-pollution function was confirmed through a self-cleaning test, while the contact angle and light transmittance were examined using special equipment. Mechanical properties, including hardness and adhesion, were confirmed using the standard hardness testing method (ASTM D3363) such as those using an H-9H, F, HB, or B-6B pencil (Mitsubishi, Japan) and a standard adhesion testing method (ASTM D3359). It was confirmed that the film coated once yielded a very low contact angle of 8.9° and very good anti-pollution properties. Its adhesion and strength also showed high values of 5B and 9H, respectively.
- Published
- 2021
- Full Text
- View/download PDF
75. Analysis of guidance laws with non-monotonic line-of-sight rate convergence
- Author
-
Hyo-Sang Shin, Seokwon Lee, and Namhoon Cho
- Subjects
Lyapunov function ,Lyapunov stability ,Heading (navigation) ,Missile Guidance ,Stability criterion ,Computer science ,Weaving Manoeuvre ,Stability (learning theory) ,Aerospace Engineering ,Missile guidance ,Stability Theory ,symbols.namesake ,Proportional Navigation Guidance ,Law ,Stability theory ,Observability Enhancement ,symbols ,Proportional navigation ,Electrical and Electronic Engineering ,Trajectory Modulation - Abstract
This study presents analyses of guidance laws that involve non-monotonic convergence in heading error from a new perspective based on an advanced stability concept. Pure proportional navigation with range-varying navigation gain is considered, and the gain condition to guarantee asymptotic convergence to the collision course is investigated while allowing the heading error to exhibit patterns that involve intermediate diversion. The extended stability criterion considered in this study allows local increase of the Lyapunov function in some finite intervals, which is less conservative than the standard Lyapunov stability theorem. The existing guidance laws involving intentional modulation of the heading error as well as the design of the navigation gain are discussed with respect to the new stability criterion.
- Published
- 2021
76. Data-driven capturability analysis for pure proportional navigation guidance considering target maneuver
- Author
-
Suwon Lee, Yongsu Han, Seokwon Lee, Youngjun Lee, Youdan Kim, and Jangseong Park
- Subjects
020301 aerospace & aeronautics ,Computer science ,Statistical verification ,Aerospace Engineering ,Sampling (statistics) ,Capturability analysis ,Statistical model ,Pursuer ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,02 engineering and technology ,Missile ,0203 mechanical engineering ,Control and Systems Engineering ,Control theory ,Kriging ,Computer Science::Systems and Control ,0202 electrical engineering, electronic engineering, information engineering ,Proportional navigation ,Probability distribution ,020201 artificial intelligence & image processing ,General Materials Science ,Configuration space ,Electrical and Electronic Engineering ,Pure proportional guidance law - Abstract
A data-driven statistical analysis of the missile’s capture region is performed. The capture region is the region of the initial geometric configuration for pursuer missile against a target in which the missile can intercept the target while satisfying specific constraints. The statistical verification approach has advantages over the analytic approach in that it can deal with various guidance algorithms and target maneuver utilizing numerical simulator. In this study, the verification model is constructed using the Gaussian process regression model. The verification model computes the probability distribution of the target capture over the initial configuration space. The data-driven capturability analysis is conducted for the maneuvering target using the Gaussian process regression model. The capture region derived from the statistical model is compared with the analytic model, and the effectiveness of the active sampling algorithm is demonstrated.
- Published
- 2021
77. Capturability of Guidance Laws for Interception of Nonmaneuvering Target with Field-of-View Limit
- Author
-
Namhoon Cho, Seokwon Lee, Sungjun Ann, and Youdan Kim
- Subjects
020301 aerospace & aeronautics ,0209 industrial biotechnology ,Computer simulation ,Computer science ,Applied Mathematics ,Aerospace Engineering ,Field of view ,02 engineering and technology ,Sliding mode control ,020901 industrial engineering & automation ,Pursuit guidance ,0203 mechanical engineering ,Space and Planetary Science ,Control and Systems Engineering ,Control theory ,Limit (mathematics) ,Electrical and Electronic Engineering ,Interception ,Homing (hematopoietic) - Abstract
The capturability of homing guidance schemes for missiles equipped with a strapdown seeker is analyzed. For air-to-air engagement, the missiles should intercept a fast-moving target while maintaini...
- Published
- 2019
- Full Text
- View/download PDF
78. Sliding Mode Guidance and Control for UAV Carrier Landing
- Author
-
Jinyoung Suk, Seokwon Lee, Youdan Kim, Seungkeun Kim, Jihoon Lee, Hyun-Jin Choi, and Somang Lee
- Subjects
020301 aerospace & aeronautics ,Computer science ,Aerospace Engineering ,02 engineering and technology ,Aerodynamics ,Kinematics ,Sea state ,Nonlinear system ,0203 mechanical engineering ,Position (vector) ,Control theory ,Control system ,Trajectory ,Electrical and Electronic Engineering - Abstract
A guidance and control system is proposed for automatic carrier landing of an unmanned aerial vehicle (UAV). To this end, the position and attitude of the carrier is predicted by considering the sea state so that the UAV guidance loop can be compensated during the final approach phase. The landing kinematics and reference trajectory are determined using the predicted touchdown position. Nonlinear guidance and control laws are designed based on a sliding-mode control scheme to make the UAV robustly follow the reference trajectory.
- Published
- 2019
- Full Text
- View/download PDF
79. CuFeO2–NiFe2O4 hybrid electrode for lithium-ion batteries with ultra-stable electrochemical performance
- Author
-
Haeseong Lim, Doh C. Lee, Jun Young Cheong, Il-Doo Kim, Su-Ho Cho, Seokwon Lee, and Jiyoung Lee
- Subjects
Materials science ,General Chemical Engineering ,chemistry.chemical_element ,Nanoparticle ,Nanotechnology ,Heterojunction ,02 engineering and technology ,General Chemistry ,Conductivity ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Delafossite ,chemistry ,Electrode ,engineering ,Lithium ,0210 nano-technology ,Current density - Abstract
Stable electrode materials with guaranteed long-term cyclability are indispensable for advanced lithium-ion batteries. Recently, delafossite CuFeO2 has received considerable attention, due to its relative structural integrity and cycling stability. Nevertheless, the low conductivity of delafossite and its relatively low theoretical capacity prevent its use as feasible electrodes for next-generation batteries that require higher reversible capacities. In this work, we suggest a simple and straightforward approach to prepare CuFeO2–NiFe2O4 by introducing Ni precursor into Cu and Fe precursor to form NiFe2O4, which exhibits higher capacity but suffers from capacity fading, through sol–gel process and subsequent heat treatments. The presence of both NiFe2O4 and CuFeO2 is apparent, and the heterostructure arising from the formation of NiFe2O4 within CuFeO2 renders some synergistic effects between the two active materials. As a result, the CuFeO2–NiFe2O4 hybrid sample exhibits excellent cycling stability and improved rate capability, and can deliver stable electrochemical performance for 800 cycles at a current density of 5.0 A g−1. This work is an early report on introducing a foreign element into the sol–gel process to fabricate heterostructures as electrodes for batteries, which open up various research opportunities in the near future.
- Published
- 2019
- Full Text
- View/download PDF
80. Thermal Analysis of Energy Storage Capacity According to Thickness of Nickel/Chromium Alloy Layer
- Author
-
Hyunil Kang, Seokhun Kwon, Won Seok Choi, Seokwon Lee, Yonghyeon Kim, and Hyeokjoo Choi
- Subjects
Technology ,Control and Optimization ,Materials science ,Alloy ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,01 natural sciences ,Chromium ,Electrical resistance and conductance ,0103 physical sciences ,co-sputtering ,microconstruction ,RF power ,nickel/chromium alloy ,Wafer ,Electrical and Electronic Engineering ,Thermal analysis ,Engineering (miscellaneous) ,010302 applied physics ,Renewable Energy, Sustainability and the Environment ,Sputter deposition ,021001 nanoscience & nanotechnology ,Nickel ,chemistry ,Electrode ,engineering ,0210 nano-technology ,Energy (miscellaneous) - Abstract
This paper examines a microconstruction consisting of nickel (Ni)/chromium (Cr) alloy thin-film. The total length of the microconstruction was 28 mm, the width was 0.2 mm, and the height was designed to be 1 μm. A thin-film of Ni/Cr alloy was co-sputtered on a silicon dioxide wafer patterned with photoresist via a RF magnetron sputtering system. The RF power ratios applied to the 4 inch target of Ni and Cr were 300 W:100 W (3:1), 300 W:150 W (2:1), and 150 W:150 W (1:1). The electrical resistance of the manufactured microconstruction was calculated and measured through Hall measurements. The temperature generated by applying 1–10 V to the microconstruction electrode was observed by using an infrared camera, and was summarized using a linear equation according to the power applied to each sample.
- Published
- 2021
81. Innovative Method Using Adhesive Force for Surface Micromachining of Carbon Nanowall
- Author
-
Hyunil Kang, Seokhun Kwon, Seokwon Lee, Jung Hyun Kim, Yonghyeon Kim, Hyeokjoo Choi, and Won Seok Choi
- Subjects
sonication ,Materials science ,General Chemical Engineering ,Adhesion ,Photoresist ,surface micromachining ,Isotropic etching ,Article ,lcsh:Chemistry ,Surface micromachining ,carbon nanowall ,lcsh:QD1-999 ,Etching (microfabrication) ,Surface modification ,General Materials Science ,Wafer ,Adhesive ,Composite material ,surface modification - Abstract
 , The application of a carbon nanowall (CNW) via transfer is very demanding due to the unusual structure of vertically grown wall-shaped that easily collapses. In addition, direct growth on a device cannot obtain a precision-patterned shape because of the temperature limit of the photoresist (PR). Therefore, in this paper, we demonstrate a new CNW surface micromachining technology capable of direct growth. In order to reduce unexpected damage caused by chemical etching, a physical force was used to etch with the adhesive properties of CNWs that have low adhesion to silicon wafer. To prevent compositing with PR, the CNW was surface modified using oxygen plasma. Since there is a risk of surface-modified CNW (SMCNW) collapse in an ultrasonic treatment, which is a physical force, the CNW was coated with PR. After etching the SMCNW grown on PR uncoated area, PR was lifted off using an acetone solution. The effect on the SMCNW by the lift-off process was investigated. The surface, chemical, and structural properties of PR-removed SMCNW and pristine-SMCNW were compared and showed a minimal difference. Therefore, the CNW surface micromachining technique was considered successful.
- Published
- 2020
82. Feasible Initial Conditions for Bias Proportional Navigation Guidance Laws Under Look Angle Constraints
- Author
-
Seokwon Lee, Jinrae Kim, and Namhoon Cho
- Subjects
0301 basic medicine ,Computer science ,Impact angle ,Error feedback ,Kinematics ,Constraint satisfaction ,Scheduling (computing) ,03 medical and health sciences ,Nonlinear system ,030104 developmental biology ,0302 clinical medicine ,Law ,Proportional navigation ,Versa ,030217 neurology & neurosurgery - Abstract
This study examines the conditions for guaranteeing stationary target interception without violating the impact angle and the look angle limit constraints during flight. Two types of new guidance laws are proposed for the constrained guidance problem in the form of a bias proportional navigation based on linear and nonlinear impact angle error feedback. Unlike the relevant previous study, both the range and the look angle are considered as the scheduling variables of the shaping functions, assuming that a constant stream of reliable range information is available. Also, the proposed guidance laws does not involve any explicit command switching. The set of feasible initial conditions are determined by the sufficient condition for guaranteeing constraint satisfaction during the entire time interval. The proposed sufficient condition can be thought of as the quantification of the set of feasible launch conditions with the desired final impact angle fixed, or vice versa.
- Published
- 2020
- Full Text
- View/download PDF
83. Clinical subtypes and prognosis in breast cancer according to parity: a nationwide study in Korean Breast Cancer Society
- Author
-
Seung Pil Jung, Se Jeong Oh, Min Ki Seong, Soo Youn Bae, Sungmin Park, Byung In Moon, Kyung Do Byun, Seokwon Lee, and Han-Byoel Lee
- Subjects
Adult ,0301 basic medicine ,Oncology ,Cancer Research ,medicine.medical_specialty ,Multivariate analysis ,Adolescent ,Breast Neoplasms ,Triple Negative Breast Neoplasms ,Kaplan-Meier Estimate ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Internal medicine ,Republic of Korea ,Biomarkers, Tumor ,Adjuvant therapy ,Humans ,Medicine ,Registries ,Stage (cooking) ,Aged ,Neoplasm Staging ,Proportional Hazards Models ,Cause of death ,Aged, 80 and over ,Biologic marker ,Univariate analysis ,business.industry ,Middle Aged ,Prognosis ,medicine.disease ,Parity ,030104 developmental biology ,Population Surveillance ,030220 oncology & carcinogenesis ,Female ,Disease Susceptibility ,Neoplasm Grading ,business ,Parity (mathematics) - Abstract
We explored the association between parity and the risk of developing a specific subtype of breast cancer. We also assessed the association between parity and prognosis according to subtypes. A total of 158,189 patients were enrolled in the Korean Breast Cancer Society Registry database between 1996 and 2015 in Korea. The database provided information on sex, age, number of parity, surgical method, stage, histological findings, presence of biologic markers, adjuvant therapy, and date and cause of death. The patients with higher parity showed a higher ratio of triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2 (HER2) subtypes. In univariate analysis, women with TNBC who had more than three children had a worse prognosis compared to other groups (HR 1.83; 95% CI 1.34–2.49; P
- Published
- 2018
- Full Text
- View/download PDF
84. Ultralow-Power 2.4-GHz Receiver With All Passive Sliding-IF Mixer
- Author
-
Seokwon Lee, Bumman Kim, and Daechul Jeong
- Subjects
Physics ,Radiation ,Noise measurement ,business.industry ,020208 electrical & electronic engineering ,Electrical engineering ,Linearity ,020206 networking & telecommunications ,02 engineering and technology ,Condensed Matter Physics ,Noise figure ,Low-noise amplifier ,Programmable-gain amplifier ,Filter (video) ,0202 electrical engineering, electronic engineering, information engineering ,Automatic gain control ,Electrical and Electronic Engineering ,business ,ISM band - Abstract
This paper presents a 2.4-GHz ISM band ultralow-power receiver with a passive sliding-IF (SIF) mixer structure. A self-biased inverter-based low noise amplifier which has high FOM and good linearity in low-power operation is employed. All passive SIF mixer is proposed to avoid power consumption in an active mixer and high-frequency operation of a nonoverlapping 4-phase generator. The passive SIF mixer is analyzed for optimization and interstage matching. A dual mode programmable gain amplifier (PGA) based on Sallen-key low-pass filter is proposed to enhance gain control range. The proposed PGA has 55 dB gain range with power consumption of 120 $\mu \text{W}$ . The overall receiver has 15–70-dB gain, 6.5-dB noise figure, −10-dBm IIP3 (at 3-MHz tone spacing), and consumes $640~\mu \text{W}$ at 2.45-GHz input frequency.
- Published
- 2018
- Full Text
- View/download PDF
85. Nanothermite of Al nanoparticles and three-dimensionally ordered macroporous CuO: Mechanistic insight into oxidation during thermite reaction
- Author
-
Doh C. Lee, Whi Dong Kim, Do Joong Shin, and Seokwon Lee
- Subjects
Length scale ,Materials science ,010304 chemical physics ,General Chemical Engineering ,Diffusion ,Composite number ,General Physics and Astronomy ,Energy Engineering and Power Technology ,Nanoparticle ,Nanotechnology ,Thermite ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Combustion ,01 natural sciences ,Fuel Technology ,Chemical engineering ,0103 physical sciences ,Gaseous diffusion ,0210 nano-technology ,Dispersion (chemistry) - Abstract
We report the synthesis and characterization of thermite composites consisting of Al nanoparticles and three dimensionally-ordered macroporous (3DOM) CuO. The pores of 3DOM CuO have size ranging between 190 nm and 320 nm and size dispersion lower than 10%, while 70 nm Al particles we used in this study are dispersed uniformly over the entire composite structures. Both the size uniformity and homogeneous mixing enable quantitative correlation between structures and thermite reaction characteristics. Ignition of the thermite composites in a closed chamber initiates thermite reactions, and the combustion kinetics is recorded in terms of the transient pressure changes. Contrary to a premise that small CuO pores would result in mixing with Al nanoparticles at a smaller length scale and hence higher pressurization rate, 3DOM CuO with pore size smaller than 240 nm exhibits gradually lower pressurization rate as pore size decreases. It turns out that pressurization rate has the highest value when the pore size of CuO is about 240 nm. The size dependence indicates that two different pathways, solid-state and gaseous diffusion, account for oxygen transfer from CuO to Al in the thermite composites. With the pore size of CuO larger than 240 nm, gas-phase diffusion predominates and pressurization rate increases as the size of the pores decreases. On the other hand, at small length scale, i.e., with CuO pore size smaller than 240 nm, condensed-phase diffusion is becoming a visibly more influential factor, reversing the size dependence. The size-dependence of the pressurization rate from thermite composites of Al nanoparticles and geometry-controlled 3DOM CuO reveals that the thermite reaction has the highest combustion rate at the smallest length scale where the gaseous diffusion still surpasses condensed-phase diffusion.
- Published
- 2018
- Full Text
- View/download PDF
86. Tamoxifen therapy improves overall survival in luminal A subtype of ductal carcinoma in situ: a study based on nationwide Korean Breast Cancer Registry database
- Author
-
Ki-Tae, Hwang, Eun-Kyu, Kim, Sung Hoo, Jung, Eun Sook, Lee, Seung Il, Kim, Seokwon, Lee, Heung Kyu, Park, Jongjin, Kim, Sohee, Oh, Young A, Kim, and Eun-Hwa, Park
- Subjects
Adult ,0301 basic medicine ,Oncology ,Cancer Research ,medicine.medical_specialty ,Receptor, ErbB-2 ,Estrogen receptor ,Breast Neoplasms ,Kaplan-Meier Estimate ,Disease-Free Survival ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Internal medicine ,Humans ,Medicine ,Registries ,skin and connective tissue diseases ,Survival rate ,Survival analysis ,Aged ,Univariate analysis ,business.industry ,Proportional hazards model ,Hazard ratio ,Middle Aged ,Ductal carcinoma ,medicine.disease ,Survival Analysis ,Tamoxifen ,Carcinoma, Intraductal, Noninfiltrating ,030104 developmental biology ,Receptors, Estrogen ,030220 oncology & carcinogenesis ,Female ,Receptors, Progesterone ,business - Abstract
To determine the prognostic role of tamoxifen therapy for patients with ductal carcinoma in situ (DCIS) according to molecular subtypes. Data of 14,944 patients with DCIS were analyzed. Molecular subtypes were classified into four categories based on expression of estrogen receptor (ER)/progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2). Kaplan–Meier estimator was used for overall survival analysis while Cox proportional hazards model was used for univariate and multivariate analyses. Luminal A subtype (ER/PR+, HER2−) showed higher (P = .009) survival rate than triple-negative (TN) subtype. Tamoxifen therapy group showed superior (P
- Published
- 2018
- Full Text
- View/download PDF
87. Selectivity of photoelectrochemical CO2 reduction modulated with electron transfer from size-tunable quantized energy states of CdSe nanocrystals
- Author
-
Seokwon Lee, Gil-Seong Kang, Doh C. Lee, Han-Ik Joh, Whi Dong Kim, Hyunjin Cho, and Kangha Lee
- Subjects
Band gap ,Chemistry ,Non-blocking I/O ,Analytical chemistry ,General Physics and Astronomy ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,Photoelectrochemical cell ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electron transfer ,Quantum dot ,Electrode ,Energy level ,0210 nano-technology ,Selectivity - Abstract
We investigate the product selectivity of CO2 reduction using NiO photocathodes decorated with CdSe quantum dots (QDs) of varying size in a photoelectrochemical (PEC) cell. Size-tunable and quantized energy states of conduction band in CdSe QDs enable systematic control of electron transfer kinetics from CdSe QDs to NiO. It turns out that different size of CdSe QDs results in variation in product selectivity for CO2 reduction. The energy gap between conduction band edge and redox potential of each reduction product (e.g., CO and CH4) correlates with their production rate. The size dependence of the electron transfer rate estimated from the energy gap is in agreement with the selectivity of CO2 reduction products for all reduction products but CO. The deviation in the case of CO is attributed to sequential conversion of CO into CH4 with CO adsorbed on electrode surface. Based on a premise that the CdSe QDs would exhibit similar surface configuration regardless of QD size, it is concluded that the electron transfer kinetics proves to alter the selectivity of CO2 reduction.
- Published
- 2018
- Full Text
- View/download PDF
88. Cu+-incorporated TiO2 overlayer on Cu2O nanowire photocathodes for enhanced photoelectrochemical conversion of CO2 to methanol
- Author
-
Hyunjin Cho, Sooho Lee, Sunil Jeong, Kangha Lee, Doh C. Lee, Whi Dong Kim, and Seokwon Lee
- Subjects
Photocurrent ,Materials science ,Inorganic chemistry ,Nanowire ,Energy Engineering and Power Technology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Photocathode ,0104 chemical sciences ,Overlayer ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Electrical resistivity and conductivity ,Titanium dioxide ,0210 nano-technology ,Faraday efficiency ,Energy (miscellaneous) - Abstract
In this paper, we report photoelectrochemical (PEC) conversion of carbon dioxide (CO2) using photocathodes based on Cu2O nanowires (NWs) overcoated with Cu+-incorporated crystalline TiO2 (TiO2 Cu+) shell. Cu2O NW photocathodes show remanent photocurrent of 5.3% after 30 min of PEC reduction of CO2. After coating Cu2O with TiO2 Cu+ overlayer, the remanent photocurrent is 27.6%, which is an increase by 5.2 fold. The charge transfer resistance of Cu2O/TiO2 Cu+ is 0.423 kΩ/cm2, whereas Cu2O photocathode shows resistivity of 0.781 kΩ/cm2 under irradiation. Mott–Schottky analysis reveals that Cu+ species embedded in TiO2 layer is responsible for enhanced adsorption of CO2 on TiO2 surface, as evidenced by the decrease of capacitance in the Helmholtz layer. On account of these electrochemical and electronic effects by the Cu+ species, the Faradaic efficiency (FE) of photocathodes reaches as high as 56.5% when TiO2 Cu+ is added to Cu2O, showing drastic increase from 23.6% by bare Cu2O photocathodes.
- Published
- 2018
- Full Text
- View/download PDF
89. Effect of Unpredictable Interference on MU-MIMO Systems in HetNet
- Author
-
Sooyong Choi, Seokwon Lee, Yosub Park, Daesik Hong, and Seokjung Kim
- Subjects
General Computer Science ,Computer science ,Distributed computing ,MIMO ,Throughput ,Data_CODINGANDINFORMATIONTHEORY ,02 engineering and technology ,Interference (wave propagation) ,beamforming ,Base station ,interference coordination ,0203 mechanical engineering ,HetNet ,Computer Science::Networking and Internet Architecture ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Computer Science::Information Theory ,MU-MIMO ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,coexistence ,General Engineering ,020302 automobile design & engineering ,020206 networking & telecommunications ,Multi-user MIMO ,Diversity gain ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:TK1-9971 ,Heterogeneous network ,Data transmission - Abstract
In this paper, we investigate the outage probability of a multiuser multiple-input multiple-output (MU-MIMO) system in the heterogeneous network (HetNet) in the presence of unpredictable interference (UI) from coexisting ad hoc systems. In order to achieve multiuser diversity gain, the MU-MIMO system requires feedback carrying the signal-to-interference-plus-noise ratio (SINR) from all active users to the base station. However, the coexisting ad hoc systems in HetNet can unpredictably initiate their data transmission during the SINR feedback duration. This unpredictable behavior by the coexisting ad hoc systems causes a mismatch between the measured SINR and the instantaneous SINR. In order to investigate the performance of the MU-MIMO system in HetNets, we first categorize the interferences into predictable interference and UI. Based on this categorization, we analyze the outage probability of an MU-MIMO system using a max-SINR scheduler. The theoretical analyses show that the MU-MIMO system cannot achieve the maximum diversity gain, since the UI from the coexisting systems causes beam selection mismatch. Additionally, we show that reducing the interval between the measurement and data transmission prevents performance degradation by reducing the effect of the unpredictable behavior of the coexisting ad hoc systems.
- Published
- 2018
- Full Text
- View/download PDF
90. Lymphocyte-activating gene-3 expression is associated with tumor-infiltrating lymphocyte levels in HER2-positive breast cancers
- Author
-
Seokwon, Lee, Jee Yeon, Kim, So Jeong, Lee, Soon Wook, Kwon, Ho Jin, Jung, Se Jin, Jung, Kyung Bin, Kim, Kyung Un, Choi, Chang Hun, Lee, Gi Yeong, Huh, and Ahrong, Kim
- Subjects
Receptor, ErbB-2 ,Programmed Cell Death 1 Receptor ,human epidermal growth factor receptor 2 ,Observational Study ,hemic and immune systems ,chemical and pharmacologic phenomena ,Breast Neoplasms ,Genes, erbB-1 ,General Medicine ,Prognosis ,Real-Time Polymerase Chain Reaction ,Lymphocyte Activation Gene 3 Protein ,B7-H1 Antigen ,Lymphocytes, Tumor-Infiltrating ,breast cancer ,Antigens, CD ,tumor-infiltrating lymphocytes ,Humans ,Female ,RNA, Messenger ,lymphocyte-activating gene-3 ,Research Article - Abstract
Lymphocyte-activating gene-3 (LAG-3, CD223) is the third inhibitory receptor targeted for immunotherapy. Several clinical trials investigating the use of interventions targeting LAG-3 are underway. The exact signaling mechanism downstream of LAG-3 is largely unknown, especially in breast cancer. The prognostic significance of tumor-infiltrating lymphocytes (TILs) in breast cancer has been previously determined. Among 167 human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients, 90 and 78 patients were positive and negative for the hormone receptor, respectively. LAG-3 mRNA and protein expression levels in TILs were evaluated by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively, among 12 and 167 HER2-positive breast cancer samples, respectively. High expression of LAG-3 in TILs was significantly correlated with high levels of TILs (P = .003) and an abundance of tertiary lymphoid structures around invasive components (P = .014). In addition, high expression of LAG3 was significantly associated with positivity for programmed death-ligand 1 (PD-L1) in tumor cells, a high immunostaining score of PD-L1 in TILs, and a high total immunostaining score for PD-L1 in tumor cells and TILs (all, P
- Published
- 2021
- Full Text
- View/download PDF
91. Room Temperature Gas Sensor Application of Carbon Nanowalls using Electrical Resistance Change by Surface Adsorption of Toxic Gases
- Author
-
Hyunil Kang, Hyeokjoo Choi, Seokhun Kwon, Gukpeel Lee, Seokwon Lee, Yonghyeon Kim, and Won Seok Choi
- Subjects
Materials science ,Mechanical Engineering ,chemistry.chemical_element ,Environmental pollution ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,symbols.namesake ,chemistry.chemical_compound ,Ammonia ,Adsorption ,chemistry ,Chemical engineering ,Electrical resistance and conductance ,Mechanics of Materials ,Plasma-enhanced chemical vapor deposition ,symbols ,General Materials Science ,Nitrogen dioxide ,0210 nano-technology ,Raman spectroscopy ,Carbon - Abstract
Carbon is not only a readily available material, but also has appropriate properties through various structural modifications. Carbon nanowalls (CNWs), based on carbon with vertical porous nanostructure, offer broad sensing surface area. Using carbon nanowalls, we demonstrated it function as gas sensing layer in our work. Carbon nanowalls synthesized via plasma enhanced chemical vapor deposition (PECVD) was in form numerous nanoflakes. In addition, various defect on its surface with high D band and low G band in Raman spectra was observed. When ammonia (NH3) and nitrogen dioxide (NO2) that may cause environmental pollution as an analyte gas were adsorbed on carbon nanowalls during exposing to them, difference in electrical resistance over 300 percentage between ammonia and nitrogen dioxide appeared. In various characteristics such as response time, sensitivity, saturation-recovery and selectivity, carbon nanowalls-based gas sensor exhibited better performance in nitrogen dioxide than ammonia. The reason for these performance is that the charge transfer of nitrogen dioxide greater than that of ammonia. In addition, the electron affinities of ammonia and nitrogen dioxide are 0.55 ± 0.10 and 2.11 ± 0.18 eV, respectively, which may sufficiently affect the each reaction between two analyte gases. Through this work, we offer several results of the proof-of-concept study for the gas sensor application of carbon nanowalls.
- Published
- 2021
- Full Text
- View/download PDF
92. Energy-efficient opportunistic spectrum access in cognitive radio networks with energy harvesting.
- Author
-
Sungsoo Park, Seokwon Lee, Beomju Kim, Daesik Hong, and Jemin Lee
- Published
- 2011
- Full Text
- View/download PDF
93. Spectrum sharing in cognitive radio networks: impacts of interference power constraints.
- Author
-
Hyungjong Kim 0001, Sungsoo Park, Seokwon Lee, and Daesik Hong
- Published
- 2011
- Full Text
- View/download PDF
94. Effect of Unmeasured Time Hours on Occupational Noise Exposure Assessment in the Shipbuilding Process in Korea
- Author
-
Hyunwook Kim, Jaewoo Shin, Seokwon Lee, and Kyoung Ho Lee
- Subjects
Working hours ,noise ,Health, Toxicology and Mutagenesis ,United States Occupational Safety and Health Administration ,Health outcomes ,Occupational noise exposure ,Article ,shipbuilding process ,Occupational safety and health ,break period ,unmeasured time hours ,Noise exposure ,Occupational Exposure ,Environmental health ,Republic of Korea ,occupational noise exposure ,Humans ,Industry ,Noise dosimeter ,Public Health, Environmental and Occupational Health ,hearing protection ,United States ,Noise ,Monitoring data ,Noise, Occupational ,Medicine ,Environmental science - Abstract
Occupational noise is known to be one of the most hazardous risk factors, frequently exceeding the exposure limit thus causing hearing loss and other health outcomes among many field workers in various industries and workplaces. This study aims to characterize the levels of occupational noise exposure during the daily working hours and break periods (sampling preparation and lunch break), identify work-related characteristics affecting the noise exposure levels when including or excluding the break periods and finally determine the most effective approach for occupational noise exposure assessment by using the Korean and U.S. OSHA’s guidelines. A total of 1575 workers employed by a large shipbuilding company participated in this study, and the historical exposure datasets of noise dosimeters, collected from 2016 to 2018, were classified by characteristics. A threshold level (TL) for the noise dosimeter was set as a value of 80 dBA during the break periods, including the preparation time for sampling instruments and one hour for the lunch break. The shipbuilding workers were exposed to high levels of occupational noise during the break periods, especially for those working in heating, grinding, and power processes in the painting-related departments. Out of 1575 samples, most cases were related to the preparation time (N = 1432, 90.9%) and lunch break (N = 1359, 86.9%). During the break time, the levels of noise exposure were measured depending on task-specific characteristics. When including the break time, the noise levels increased by approximately 1 dBA during the break, combining 0.8 dBA in the lunch hours and 0.2 dBA for the preparation of the sampling instrument. When excluding the break time, the levels of noise exposure collected using a Korean Occupational Safety and Health Administration (KOSHA) guide tended to be underestimated compared to those using the U.S. OSHA method. When including the break times, the proportion of noise exposure levels exceeding the compliance exposure limit declined from 37.9% to 34.5%, indicating that the break times might affect the decrease in the noise exposure levels. Taken together, shipbuilding workers could possibly be exposed to much greater amounts of noise exposure during break times in the shipbuilding processes, and the noise exposure levels in the department of painting were high. Therefore, it is recommended that industrial hygienists collect exposure monitoring data of occupational noise one hour after their job tasks begin and then consecutively monitor the noise exposure levels for at least 6 h including the break periods for each day.
- Published
- 2021
- Full Text
- View/download PDF
95. Immediate chest wall reconstruction using an external oblique myocutaneous flap for large skin defects after mastectomy in advanced or recurrent breast cancer patients: A single center experience
- Author
-
Youngtae Bae, Seokwon Lee, and Younglae Jung
- Subjects
Adult ,medicine.medical_specialty ,Mammaplasty ,medicine.medical_treatment ,Breast Neoplasms ,030230 surgery ,Single Center ,Skin Diseases ,Chest wall reconstruction ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Humans ,Medicine ,Stage (cooking) ,Thoracic Wall ,Recurrent breast cancer ,Mastectomy ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,General Medicine ,Middle Aged ,Plastic Surgery Procedures ,Prognosis ,University hospital ,medicine.disease ,Myocutaneous Flap ,Surgery ,Oncology ,External oblique myocutaneous flap ,030220 oncology & carcinogenesis ,Female ,Neoplasm Recurrence, Local ,business ,Follow-Up Studies - Abstract
Background and Objectives We report 75 single-stage chest-wall reconstructions using ipsilateral external oblique myocutaneous flap (EOMCF) to cover the extensive skin defects following resection of advanced or recurrent breast tumours at the Pusan National University Hospital. Methods Between January 2007 and October 2015, 75 women with advanced or recurred breast cancer who underwent extensive mastectomy with immediate chest wall reconstruction using EOMCF were reviewed retrospectively. Results Mean age was 50.5 ± 9.8 years and mean follow-up period was 36.7 ± 25.1 months. A total of 59 patients (78.7%) had stage III disease and the remaining 16 patients (21.3%) had stage IV. Mean excised breast tissue weight was 687.6 ± 416.5 g (range, 120.3-2797.1 g). The mean chest wall skin defect covered with an EOMCF was 228.3 ± 168.1 cm2 and corresponded to an approximately 15 × 15 cm defect. Average operative time for reconstruction was
- Published
- 2017
- Full Text
- View/download PDF
96. Expanding depletion region via doping: Zn-doped Cu2O buffer layer in Cu2O photocathodes for photoelectrochemical water splitting
- Author
-
Han-Ik Joh, Doh C. Lee, Cheol-Ho Lee, Il-Doo Kim, Seokwon Lee, Jun Young Cheong, and Kangha Lee
- Subjects
Photocurrent ,business.industry ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,Doping ,Heterojunction ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Photocathode ,0104 chemical sciences ,Ion ,Depletion region ,Optoelectronics ,Water splitting ,0210 nano-technology ,business - Abstract
We report photoelectrochemical hydrogen evolution reaction using a Cu2O-based photocathode with a layer doped with Zn ions. The doping results in the shift of the onset flat-band potential of the photocathode, likely a consequence of maximized band-bending in the Cu2O/Zn : Cu2O heterojunction. Systematic electrochemical analysis reveals that expansion of depletion region is responsible for the enhanced photoelectrochemical performance, e.g., the increase of photocurrent and reduced internal resistance.
- Published
- 2017
- Full Text
- View/download PDF
97. Identification of a novel splicing mutation within SLC17A8 in a Korean family with hearing loss by whole-exome sequencing
- Author
-
Hong-Joon Park, Jinwoong Bok, Byeonghyeon Lee, Seokwon Lee, Chan Ik Park, Tae-Jun Kwon, Kyu-Yup Lee, Jeong-In Baek, Un-Kyung Kim, and Nari Ryu
- Subjects
Adult ,Male ,0301 basic medicine ,Hearing loss ,RNA Splicing ,Biology ,DNA sequencing ,03 medical and health sciences ,symbols.namesake ,0302 clinical medicine ,Republic of Korea ,Vesicular Glutamate Transport Proteins ,Genetics ,medicine ,Humans ,Exome ,Hearing Loss ,Exome sequencing ,Aged ,Sanger sequencing ,Massive parallel sequencing ,Genetic heterogeneity ,General Medicine ,Pedigree ,030104 developmental biology ,SLC17A8 ,Mutation ,Mutation (genetic algorithm) ,symbols ,Female ,medicine.symptom ,030217 neurology & neurosurgery - Abstract
Hereditary hearing loss (HHL) is a common genetically heterogeneous disorder, which follows Mendelian inheritance in humans. Because of this heterogeneity, the identification of the causative gene of HHL by linkage analysis or Sanger sequencing have shown economic and temporal limitations. With recent advances in next-generation sequencing (NGS) techniques, rapid identification of a causative gene via massively parallel sequencing is now possible. We recruited a Korean family with three generations exhibiting autosomal dominant inheritance of hearing loss (HL), and the clinical information about this family revealed that there are no other symptoms accompanied with HL. To identify a causative mutation of HL in this family, we performed whole-exome sequencing of 4 family members, 3 affected and an unaffected. As the result, A novel splicing mutation, c.763+1G>T, in the solute carrier family 17, member 8 (SLC17A8) gene was identified in the patients, and the genotypes of the mutation were co-segregated with the phenotype of HL. Additionally, this mutation was not detected in 100 Koreans with normal hearing. Via NGS, we detected a novel splicing mutation that might influence the hearing ability within the patients with autosomal dominant non-syndromic HL. Our data suggests that this technique is a powerful tool to discover causative genetic factors of HL and facilitate diagnoses of the primary cause of HHL.
- Published
- 2017
- Full Text
- View/download PDF
98. Spatiotemporal expression patterns of clusterin in the mouse inner ear
- Author
-
Jeong Oh Shin, Seokwon Lee, Jinwoong Bok, Borum Sagong, and Un-Kyung Kim
- Subjects
0301 basic medicine ,Pathology ,medicine.medical_specialty ,Histology ,Fluorescent Antibody Technique ,Gene Expression ,In situ hybridization ,Pathology and Forensic Medicine ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Downregulation and upregulation ,otorhinolaryngologic diseases ,medicine ,Animals ,Inner ear ,RNA, Messenger ,Cochlea ,Messenger RNA ,biology ,Clusterin ,Gene Expression Regulation, Developmental ,Cell Biology ,Cell biology ,Mice, Inbred C57BL ,030104 developmental biology ,medicine.anatomical_structure ,Organ of Corti ,Ear, Inner ,Chaperone (protein) ,biology.protein ,Female ,sense organs ,030217 neurology & neurosurgery - Abstract
Clusterin (CLU) is an extracellular chaperone protein that is implicated in diverse physiological and pathophysiological cellular processes. CLU expression is upregulated in response to cellular stress and under certain conditions, such as neurodegenerative disease and cancer. CLU primarily functions as a chaperone that exerts cytoprotective effects by removing cellular debris and misfolded proteins and also acts as a signaling molecule that regulates pro-survival pathways. Deafness is caused by genetic factors and various extrinsic insults, including ototoxic drugs, exposure to loud sounds and aging. Considering its cytoprotectivity, CLU may also mediate cellular defense mechanisms against hearing loss due to cellular stresses. To understand the function of CLU in the inner ear, we analyze CLU expression patterns in the mouse inner ear during development and in the adult stage. Results of quantitative real-time polymerase chain reaction analysis showed that Clu mRNA levels in the inner ear were increased during embryogenesis and were constantly expressed in the adult. Detailed spatial expression patterns of Clu both in the mRNA and protein levels were analyzed throughout various developmental stages via in situ hybridization and immunofluorescence staining. Clu expression was found in specific domains of developing inner ear starting from the otocyst stage, mainly adjacent to the prosensory domain of the cochlear epithelium. In the mature inner ear, Clu expression was observed in Deiter's cells and pillar cells of the organ of Corti, outer sulcus and in basal cells of the stria vascularis in the cochlea. These specific spatiotemporal expression patterns suggest the possible roles of CLU in inner ear development and in maintaining proper hearing function.
- Published
- 2017
- Full Text
- View/download PDF
99. Adsorption kinetics and isotherms of phosphate and its removal from wastewater using mesoporous titanium oxide
- Author
-
Warangkana Jutidamrongphan, Ki Young Park, Seokwon Lee, and Kwanyong Lee
- Subjects
chemistry.chemical_compound ,Adsorption kinetics ,Wastewater ,Phosphate adsorption ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,Kinetics ,Mesoporous material ,Phosphate ,Water Science and Technology ,Titanium oxide ,Nuclear chemistry - Published
- 2017
- Full Text
- View/download PDF
100. Temporal and spatial expression patterns of Hedgehog receptors in the developing inner and middle ear
- Author
-
Harinarayana Ankamreddy, Seokwon Lee, Naga Mahesh Jakka, Jinwoong Bok, Un Kyung Kim, and Jeong Oh Shin
- Subjects
0301 basic medicine ,Patched ,Embryology ,Neurogenesis ,Ear, Middle ,Cell Cycle Proteins ,Receptors, Cell Surface ,Biology ,GPI-Linked Proteins ,Mice ,03 medical and health sciences ,Pregnancy ,otorhinolaryngologic diseases ,medicine ,Animals ,Hedgehog Proteins ,Inner ear ,Sonic hedgehog ,Hedgehog ,Mice, Inbred ICR ,Hair cell differentiation ,Anatomy ,Embryonic stem cell ,Cell biology ,Patched-1 Receptor ,030104 developmental biology ,medicine.anatomical_structure ,PTCH1 ,Ear, Inner ,Immunoglobulin G ,Middle ear ,biology.protein ,Female ,sense organs ,Cell Adhesion Molecules ,Signal Transduction ,Developmental Biology - Abstract
The mammalian inner ear is a complex organ responsible for balance and hearing. Sonic hedgehog (Shh), a member of the Hedgehog (Hh) family of secreted proteins, has been shown to play important roles in several aspects of inner ear development, including dorsoventral axial specification, cochlear elongation, tonotopic patterning, and hair cell differentiation. Hh proteins initiate a downstream signaling cascade by binding to the Patched 1 (Ptch1) receptor. Recent studies have revealed that other types of co-receptors can also mediate Hh signaling, including growth arrest-specific 1 (Gas1), cell-adhesion molecules-related/down-regulated by oncogenes (Cdon), and biregional Cdon binding protein (Boc). However, little is known about the role of these Hh co-receptors in inner ear development. In this study, we examined the expression patterns of Gas1, Cdon, and Boc, as well as that of Ptch1, in the developing mouse inner ear from otocyst (embryonic day (E) 9.5) until birth and in the developing middle ear at E15.5. Ptch1, a readout of Hh signaling, was expressed in a graded pattern in response to Shh signaling throughout development. Expression patterns of Gas1, Cdon, and Boc differed from that of Ptch1, and each Hh co-receptor was expressed in specific cells and domains in the developing inner and middle ear. These unique and differential expression patterns of Hh co-receptors suggest their roles in mediating various time- and space-specific functions of Shh during ear development.
- Published
- 2017
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.