Electrodeposited Pt to CO tolerance in PEM Fuel Cells

주지용,권영국,이재광,이재영 한국공업화학회 2008 한국공업화학회 연구논문 초록집 Vol.2008 No.1

그래핀의 저온 연료전지 활용방안

주지용,이재광,이재영 한국화학공학회 2014 NICE Vol.32 No.4

두경부에 발생한 골수외형질세포종

주지용,박재용,권기륜,구본석,나기상 대한이비인후과학회 2014 대한이비인후과학회지 두경부외과학 Vol.57 No.2

Background and Objectives Head and neck solitary extramedullary plasmacytomas (EMP) are rare neoplasms of plasma cell origin. Literature review reveals only small numbers of reports. The objective was to review our experience of treating patients of this neoplasm and to compare with the analysis of EMP cases reported in Korean literature. Subjects and Method A retrospective review of all patients treated for EMP of the head and neck at the Chungnam National University Hospital between 1985 and 2012 was performed. Eleven patients with head and neck EMP were identified and included in this study. Results The mean age of our cases diagnosed was 51.6 years, with the range of 25 to 69 years. There was a strong male preponderance (M:F=10:1). The sinonasal tract was the most common site (six patients) of the disease, followed by the pharynx and larynx in frequency. Four patients were treated by surgery, four by surgery and radiation, two by chemoradiation, and one by radiation. The mean follow-up was 80 months. Local recurrence developed in one patient. The time from diagnosis to local recurrence was 60 months. Two patients developed multiple myeloma, and the time took to develop multiple myeloma from the date of diagnosis of EMP was 9 and 177 months, respectively. Korean literature review (19 cases) showed similar aspects in terms of prevalent age, origin site, and treatment modalities, but equal sex ratio and low recurrence rate. Conclusion We described 11 Korean cases of EMP. Long-term follow-up is essential because local recurrence and disseminated disease can occur many years after treatment. Korean J Otorhinolaryngol-Head Neck Surg 2014;57:103-7

Effects of Landing Foot Orientations on Biomechanics of Knee Joint in Single-legged Landing

주지용,김영관 한국운동역학회 2018 한국운동역학회지 Vol.28 No.2

Objective: This study aimed to investigate the influence of landing foot orientations on biomechanics of knee joint in order to identify vulnerable positions to non-contact knee injuries during single-legged landing. Method: Seventeen men (age: 20.5±1.1 years, height: 175.2±6.4 cm, weight: 68.8±5.8 kg) performed single-leg drop landings repeatedly with three different landing foot orientations. They were defined as toe-in (TI) 30° adduction, neutral (N, neutral), and toe-out (TO) 30° abduction positions. Results: The downward phase time of TI was significantly shorter than those of N and TO. The flexion and valgus angle of N was greater than those of TI and TO at the moment of foot contact. At the instance of maximum knee flexion, N showed the largest flexion angle, and TO position had the largest varus and external rotation angles. Regarding ground reaction force (GRF) at the moment of foot contact, TO showed the forward GRF, while others showed the backward GRF. TI indicated significantly larger mediolateral GRF than others. As for the maximum knee joint force and joint moment, the main effect of different foot positions was not significant. Conclusion: TI and TO might be vulnerable positions to knee injuries because both conditions might induce combined loadings to knee joint. TI had the highest mediolateral GRF with a shortest foot contact time, and TO had induced a large external rotation angle during downward phase and the peak forward GRF at the moment of foot contact. Conclusively, N is the preferred landing foot orientation to prevent non-contact knee injuries.

SLODAR System Development for Vertical Atmospheric Disturbance Profiling at Geochang Observatory

주지용,하현승,이준호,정도환,김영수,Timothy Butterley 한국광학회 2024 Current Optics and Photonics Vol.8 No.1

Implemented at the Geochang Observatory in South Korea, our slope detection and ranging (SLODAR) system features a 508 mm Cassegrain telescope (f /7.8), incorporating two Shack-Hartmann wave-front sensors (WFS) for precise measurements of atmospheric phase distortions, particularly from nearby binary or double stars, utilizing an 8 × 8 grid of sampling points. With an ability to reconstruct eight-layer vertical atmospheric profiles, the system quantifies the refractive index structure function (Cn2) through the crossed-beam method. Adaptable in vertical profiling altitude, ranging from a few hundred meters to several kilometers, contingent on the separation angle of binary stars, the system operates in both wide (2.5 to 12.5 arcminute separation angle) and narrow modes (11 to 15 arcsecond separation angle), covering altitudes from 122.3 to 611.5 meters and 6.1 to 8.3 kilometers, respectively. Initial measurements at the Geochang Observatory indicated Cn2values up to 181.7 meters with a Fried parameter (r 0 ) of 8.4 centimeters in wide mode and up to 7.8 kilometers with an r 0 of 8.0 centimeters in narrow mode, suggesting similar seeing conditions to the Bohyun Observatory and aligning with a comparable 2014–2015 seeing profiling campaign in South Korea.

Effects of Customized 3D-printed Insoles on the Kinematics of Flat-footed Walking and Running

주지용,김영관 한국운동역학회 2018 한국운동역학회지 Vol.28 No.4

Objective: Flat-footed people struggle with excessive ankle joint motion during walking and running. This study aimed to investigate the effects of customized three-dimensional 3D-printed insoles on the kinematics of flat-footed people during daily activities (walking and running). Method: Fifteen subjects (height, 169.20 ± 2.61 cm; age, 22.87 ± 8.48 years; navicular bone height, 13.2 ± 1.00 mm) diagnosed with flat feet in a physical examination participated in this study. Results: The customized 3D-printed insoles did not significantly affect 3D ankle joint angles under walking and running conditions. However, they shifted the trajectory of the center of pressure (COP) laterally during fast walking, which enhanced the load distribution on the foot during the stance phase. Conclusion: The customized 3D-printed insoles somewhat positively affected the pressure distribution of flat-footed people by changing the COP trajectory. Further research including comparisons with customized commercial insoles is needed.

노인 체력 측정 결과와 보행 특성의 관계

주지용,황연희,김영관 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.1

본 연구는 65세에서 85세 사이의 남녀 노인 200명을 대상으로 노인 체력 측정과 보행 검사를 실시하여 노인의 체력 변인과 보행 특성 간의 관계를 조사하고자 하였다. 연구 대상자는 65세에서 85세 사이의 노인 200명으로 노인 체력 검사(Senior Fitness Test) 항목 6개와 추가 체력검사 3개(수직점프, 외발서기, 악력) 및 보행 측정을 수행하였다. 보행은 신발에 장착된 가속도계 기반 보행 측정 장비를 사용하였다. 이원분산분석, 주요인분석, 상관관계 분석을 실시하여 연령에 따른 영향과 변인들 간의 관계성을 파악하였다. 실험 결과 나이에 따라 보행 능력(보장, 6분 걷기), 제지방량, 체력(아령 들기)의 유의한 감소가 있었다(p<.05). 33개의 체력 및 보행 변인을 대상으로 주성분 분석을 실시한 결과 5개의 주성분(보행 특성, 신체 특성, 보행 가변성, 체지방 요인, 체력 요인)이 나타났으며 전체 가변성의 64.7% 설명력을 나타냈다. 보행 시 편한 보속은 보폭, 외발지지 시간과는 정적 상관, 양발지지 시간, 보행 가변성 변인들과는 부적 상관을 나타냈다(p<.05). 노인들의 삶의 질을 유지하려면 보행 능력이 매우 중요하며 이것은 근력운동을 통해 유지 또는 개선되어야 한다. This study investigated the relationship among gait variables and physical fitness variables for Korean elderly people. Two hundred elderly people aged 65 to 85, (100 men and 100 women) participated in this study. They performed senior fitness test consisting of 6 tests, 3 additional physical tests (vertical jump, one leg stand, and grip force), body composition measures, and gait test. The gait test used shoes having an inertia measurement device in the outer-soles. The results indicated that the stride length, 6-min walking, lean body mass, and dumbbell curls were significantly affected by age (the above 75 group vs. the below 75 group). Among 33 measured parameters, the principal component analysis (PCA) revealed five PCs such as gait characteristics, physical features, gait variability, and fitness levels. In addition, the correlation analysis showed that the preferred walking speed was significantly, positively associated with stride length and single support time, whereas it was negatively associated with double support time and gait variability.(Ed note: please confirm my modification) In conclusion, sarcopenia should be avoided in elderly people, and resistance exercise is highly recommended to help elderly people maintain their gait ability.

악하선관 전위술로 치료한 수면 중 침흘림 1예

주지용,김성하,구본석,윤여훈 대한이비인후과학회 2013 대한이비인후과학회지 두경부외과학 Vol.56 No.2

Sialorrhea, or drooling, is defined as excessive salivary spillage from the mouth. The exact pathophysiology of drooling is unknown but appears to be a defect in the oral phase of swallowing. The most common cause of drooling is cerebral palsy in children and Parkinson disease in adults. Drooling can cause various medical and psychosocial problems. Various treatment modalities include physical therapy, anticholinergic medications, botulinum toxin injection into salivary glands, and surgical procedures. We report a case of 22-year-old woman with excessive drooling during sleep, which was treated with Wharton’s duct relocation.

Engineering perspective of electrochlorination system for ballast water treatment using carbon dioxide

주지용,박동현,이태진,이지형 한국마린엔지니어링학회 2022 한국마린엔지니어링학회지 Vol.46 No.3

Electrochlorination systems are widely used in ballast water treatment because they are more cost-effective than other dis-infection techniques. Furthermore, the on-board generation of hypochlorous acid from electrochlorination systems has advantages in terms of footprint size and safety as there is no need to store highly concentrated hypochlorite solutions. Recently, several studies focused on the injection of carbon dioxide into an electrochlorination system to enhance disinfection efficacy. However, the treatment efficacy of injecting exhaust gas into an electrochlorination system remains understudied. In this study, the disinfection efficacy of Artemia sp. was investigated based on the holding time when carbon dioxide was injected into the electrochlorination system. Disin-fection efficacy significantly improved as the pH decreased to 5.5. Additionally, the pH inside the ballast water tank adjusted based on ballast water flow capacity when the carbon dioxide from combustion engine was fully dissolved. Our results showed that the pH suitable for eliminating microorganisms was achieved using only the auxiliary engine without any acid additives. This study provides a promising conceptual design for ballast water treatment.

Development and Characterization of an Atmospheric Turbulence Simulator Using Two Rotating Phase Plates

주지용,한석기,이준호,이혁교,허준,이기훈,박상영 한국광학회 2022 Current Optics and Photonics Vol.6 No.5

We developed an adaptive optics test bench using an optical simulator and two rotating phase plates that mimicked the atmospheric turbulence at Bohyunsan Observatory. The observatory was reported to have a Fried parameter with a mean value of 85 mm and standard deviation of 13 mm, often expressed as 85 ± 13 mm. First, we fabricated several phase plates to generate realistic atmospheric-like turbulence. Then, we selected a pair from among the fabricated phase plates to emulate the atmospheric turbulence at the site. The result was 83 ± 11 mm. To address dynamic behavior, we emulated the atmospheric disturbance produced by a wind flow of 8.3 m/s by controlling the rotational speed of the phase plates. Finally, we investigated how closely the atmospheric disturbance simulation emulated reality with an investigation of the measurements on the optical table. The verification confirmed that the simulator showed a Fried parameter of 87 ± 15 mm as designed, but a little slower wind velocity (7.5 ± 2.5 m/s) than expected. This was because of the nonlinear motion of the phase plates. In conclusion, we successfully mimicked the atmospheric disturbance of Bohyunsan Observatory with an error of less than 10% in terms of Fried parameter and wind velocity.