주행차량의 공기역학적 주행안전성 평가를 위한 알고리즘 개발연구

김창선(Chang-Sun Kim),이승현(Seung-Hyun Lee),김철호(Chul-Ho Kim) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5

The objectives of vehicle aerodynamic design is on the fuel economy, reduction of the harmful emissions and minimizing vibration and noise and the driving stability of the vehicle. Especially in case of a sedan, aerodynamic driving stability of a vehicle is the main focus, and for this, the proper evaluation of aerodynamic driving stability of a vehicle is required. In this study, we yield the size of moving moment on the body of the vehicle generated by side wind when sedan type vehicle drives on the road and complete a numerical algorithm to evaluate aerodynamic driving stability of a vehicle judging whether such moving moment has a serious impact on vehicle driving stability. The model vehicle for the study is sedan type vehicle shape recommended by SAE. In the study, we yield the pressure drag and the position of C.P. on the body of the vehicle generated when the vehicle drives with side wind using CFD technique. Based on this, we also calculated pitching, rolling and yawing moment of the body of the vehicle generated on the center of gravity, and the result from comparing turning moment values and the size of rotational resistance moment of the body of the vehicle can be used as the basis to judge driving stability such as off-course and rollover of the vehicle. After driving stability of a vehicle when the vehicle drives 100km/h with 15m/s side wind is evaluated using the numerical algorithm drawn from the study, the value of yawing moment is 606N.m, rolling moment -773N.m and pitching moment 84N.m. These values are smaller than each value of rotational resistance moment the model vehicle has, and therefore, the model vehicle’s driving stability is guaranteed when driving 100km/h with 15m/s side wind.

운동강도의 차이가 고령 골감소증 여성의 골대사지표 및 RANKL/RANK/OPG 시스템 사이토카인에 미치는 영향

김창선 ( Chang-sun Kim ),김효진 ( Hyo-jin Kim ),김지연 ( Ji-yeon Kim ),김지원 ( Ji-won Kim ),박동호 ( Dong-ho Park ),임승택 ( Seung-taek Lim ),민석기 ( Seok-ki Min ) 한국운동생리학회(구 한국운동과학회) 2017 운동과학 Vol.26 No.1

PURPOSE: Regular exercise augments the bone mineral density in postmenopausal elderly women. However, its acute effects by different intensities on bone metabolic markers and cytokines of the RANKL/RANK/OPG system have not been determined. Our aim was to investigate the effects exercise intensity difference on these markers and RANKL/RANK/OPG system in Korean osteopenia elderly women. METHODS: Twelve osteopenia elderly women (T-score -2.46±0.48; aged 68.17±3.04 years) examined these markers and RANKL/RANK/OPG system responses to acute high (80% VO₂max ; HIGH group), low (40% VO₂max; LOW group) intensity with a cycle ergometer, and sedentary rest (CON group) in a randomized, cross-over repeated measures design. The concentrations of bone metabolic markers and cytokines measured before, immediately after and then recovery 60 minutes after exercise. mRNA expressions of RANKL & OPG from PBMC were also measured at same times. RESULTS: There were no significant changes in the serum CTx and RANKL, and mRNA expression of RNAKL, indicating bone resorption (NS). On the other hand, although the serum OPG showed significant change in high intensity (p=.027; group×time), the serum OC showed significant change in low intensity (p=.044; group×time), indicating bone formation, respectively. CONCLUSIONS: These results suggest that a single bout exercise might effect on bone formation alone with OPG responds to high intensity, OC responds to low intensity. Additional studies are needed on the difference in change between OC and OPG due to exercise intensity.

능동 적외선열화상 전산해석적 결과를 통한 크랙 정량화 검출능 비교 분석

김창선(Chang Sun Kim),이민우(Min Woo Lee),육성열(Sung Yeal Yuk),이승주(Seung Ju Lee),김원태(Won Tae Kim) 한국비파괴검사학회 2022 한국비파괴검사학회 춘계학술대회 초록집 Vol.2022 No.5

Ti-Blade 선형결함에 대한 LIT 탐상 검출능 및 Sizing에 대한 실험적 고찰

김창선(Chang Sun Kim),이승주(Seung Ju Lee),김원태(Won Tae Kim) 한국비파괴검사학회 2021 한국비파괴검사학회 춘계학술대회 초록집 Vol.2021 No.6

발전설비의 효율 증대는 증기가 가진 에너지를 최대한 활용하는 것이 필요하며, 이를 위해 발전용 터빈의 경우보다 큰 Size의 최종단 블레이드(LSB, Last Stage Blade)를 적용하는 추세이다. Titanium 소재 저압터빈 로터의 LSB (Last Stage Blade)의 경우 대표적인 비자성체 소재로서 현재 Blade Vane을 포함한 표면 검사는 VT와 PT를 적용한 비파괴검사가 주를 이루고 있고 일부에서는 ECT를 적용한 비파괴검사 방법 개발이 추진되고 있는 실정이다. 본 논문에서는 위상잠금 적외선열화상 기법을 활용하여 실제 발전소에서 취외한 Ti-LSB에 가공된 다양한 깊이의 인공선형결함에 대해 각 결함 깊이 간의 식별 여부를 확인하고 깊이를 구분해 낼 수 있는지를 분석 대상으로 하였으며, LIT 실험을 통해 취득된 Data에 대해 결함의 검출과 평가에 용이하도록 결함 분석용 툴로서 MATLAB을 활용하였다. 4개의 인공선형결함에 대해 각각의 구역(Zone)을 설정하고 건전부 기준점과 결함부의 중심점을 위치 선정하여 4점 상관법에 의해 S1~S4 시점에서의 온도값을 기준으로 각 위치에서의 위상(φ)과 진폭(A)값을 산출하고 비교 분석하였다. 본 연구의 결과로서 결함평가가 용이한 구간을 선정할 수 있었으며, 플레이트 형태가 아닌 형상이 복잡한 Ti-Blade에서의 결함의 깊이에 따른 위상과 진폭 및 온도차와의 상관관계를 확인할 수 있었다. Increasing the efficiency of power generation facilities requires the most use of the energy of steam, and for this purpose, a larger size of last stage blade (LSB) is applied to power generation turbines. In the case of LSB (Last Stage Blade) of low-pressure turbine rotors of Titanium, surface inspections including Blade Vane are mainly non-destructive tests with VT and PT, and some are developing non-destructive testing methods with ECT. In this paper, MATLAB was used as a tool for fault analysis to facilitate detection and evaluation of defects on data acquired through LIT experiments, to verify the different depth of artificial linear defects machined in Ti-LSB. The four-point correlation method calculates and analyzes the phase (φ) and amplitude (A) values at each location based on the temperature values at S1 to S4 points by establishing each zone for each of the four artificial linear defects and selecting the center point of the defects. As a result of this study, we were able to select sections that were easy to evaluate defects, and to correlate the phase with amplitude and temperature differences in Ti-Blade, which are complex in shape rather than plate form.

장기간의 수영운동에 따른 흰쥐의 골염량 및 사료효율의 변화

김창선 ( Chang Sun Kim ) 한국운동영양학회 2008 Physical Activity and Nutrition (Phys Act Nutr) Vol.12 No.1

인체 감지 제어 기능을 갖는 UV LED Bar의 최적 설계

김창선(Chang Sun Kim,)이재학(Jae Hak Lee,)고영진(Young Jin Goh) 한국전자통신학회 2017 한국전자통신학회 논문지 Vol.12 No.6

본 논문에서는 다용도로 사용 가능한 UV LED 바의 최적설계를 하였다. UV LED는 자외선을 방출하기 때문에 사용목적상 일정하게 자외선을 방출하는 것이 중요하다. 일정한 자외선이 방출되기 위해서는 동작 가능 입력 전압 범위 내에서 정전류원으로 구동되어야 하고 자외선 활용 특성 상 자외선 방출 유지 시간이 길기 때문에 방열이 특히 중요하다. 따라서 소비전력이 최소화 되도록 설계해야 한다. 또한 인체 보호가 필수적이기 때문에 거리 감지 센서와 블루투스를 이용해 인체 감지 여부에 따라 동작할 수 있게 알고리즘을 구성하였다. 자외선 UVA를 방출하기 위해 365nm UV LED 3개가 직렬로 사용되었으며 입력 전압 12V와 정전류 500mA에서 동작하며 효율은 87.5%, 소비전력은 6.006W이다. 그리고 자외선 조사량은 루트론 계측기로 측정하였을 경우 10cm 거리에서 5.35mW/cm2으로 측정 되었다. In this paper, it is performed the optimal design of the UV LED bar which can be used variously. The UV LED Bar emits ultraviolet rays, so it is important to emit ultraviolet rays constantly for the purpose of use. In order to emit a certain amount of ultraviolet rays as ever, the ultraviolet ray emission should be driven by a constant current source within the operable input voltage range. And also the heat dissipation is particularly important because of the long ultraviolet emission retention time due to the UV utilization characteristics. In addition, since human body protection is essential, the algorithm is configured to operate according to human body detection using distance sensor and Bluetooth. Three 365nm UV LEDs were used in series to emit ultraviolet UVA, operating at the constant current of 500mA with an efficiency of 87.5% and a power consumption of 6.006W. The ultraviolet radiation dose was measured at 5.35 mW / cm2 at the distance of 10 cm when measured by the Lutron ultraviolet measuring instruments.

흰쥐의 후지체공에 따른 앞다리와 뒷다리의 골밀도 차이

김창선(Chang-sun Kim) 한국생활환경학회 2011 한국생활환경학회지 Vol.18 No.3

Mechanical forces play a pivotal role in maintaining bone mass. Tail-suspension has long been employed to induce a pattern of osteopenia in rats and it has been used as a ground-based model for the spaceflight. This study was designed to clarify the change of BMD between the fore- and hind-limb induced by non-weight-bearing, eighteen 7-week-o1d female spraque-dawley rats completed tail-suspension for 2-week. After a week of stabilization, rats were randomly divided into three groups: before tail-suspension group (n=6, before), non-suspension control group (n=6, Con) and tail-suspension group (n=6, Sus). The rats were fed standard lab chow (CRF-l, Charles River, Japan) and water ad libitum while Con group were pair fed with the appropriate suspension rats for control of caloric intake. At before and after 2-week suspension, rats were sacrificed and femur and humerus were removed for analysis of bone mineral density (BMD) by dual energy X-ray absorptionmetry (DEXA, Lunar DPXL, DSA). Serum and twenty four hours urinary calcium (Ca) and phosphate (P) were determined by biochemical markers of bone metabolism. BMD of femur in the Con group were increased in approximately 16.5% as compared with that of the before group (p<.001), but that of the Sus group did not increased, and showed approximately 11.2% lower than that of the Con group(p<.01). However, BMD of humerus in the both group showed no difference between the Con and the Sus group(NS). Similarly, BMC of femur in the Con group were increased in approximately 45.5% as compared with that of the before group (p<.001), but that of the Sus group was small, and showed approximately 14.5% lower than that of the Con group (p<.01). However, BMC of humerus in the both group showed no difference between the Con and the Sus group (NS). The femur weight of the Sus group was decreased approximately in 8% as compared to the Con group (p<.05), but the humerus weight showed no difference between the Con and the Sus group. On the other hand, the serum Ca concentration and twenty four hours urinary Ca excretion between the Con and the Sus group showed similar levels. Twenty four hours urinary P excretion of the Sus group, however, dynamically decreased approximately 50% lower than that of the Con group (P<.05) while serum P concentration was increased (p<.001). These results suggest that the bone loss was occurred mainly a part of non-weight bearing, and that disturbed P homeostasis in this process.

2주간의 뒷다리 부유 후 흰쥐의 골밀도 변화

김창선 ( Chang Sun Kim ),박동호 ( Dong Ho Park ) 한국스포츠정책과학원(구 한국스포츠개발원) 2005 체육과학연구 Vol.16 No.3

본 연구는 미세중력환경에 의해 발생하는 골량감소 및 골대사의 변화 기전을 밝히기 위한 것이다. 이를 위해 생후 8주령 된 암컷 흰쥐 (SD계) 18마리를 무작위로 실험전 비교 집단(n=6, BC), 2주간 무처치 대조집단(n=6, Non), 2주간 뒷다리 부유집단(n=6, Sus)의 3집단으로 나누었다. 멸균사료(CRF-1, Charles River, JAPAN)의 섭취는 모든 실험쥐가 동일분량을 섭취하도록 전날 뒷다리 부유집단이 섭취한 분량을 다음날 무처치집단이 섭취하는 방법으로 엄격하게 통제 하였다. 뒷다리 부유는 두부의 각도가 약 35~40도가 되도록 꼬리의 높이를 조절하여 실시하였다. 실험개시 및 2주 동안의 실험 기간 종료 후, 모든 실험쥐는 12시간 절식 후 복부 대동맥으로부터의 채혈과 함께 도살 되었고, DEXA법 및 pQCT를 이용하여 각각 대퇴골 및 피질골과 해면골의 골밀도를 측정하였다. Sus집단의 대퇴골 중량은 Non집단과 비교하여 약 8 %의 유의한 감소를 나타내었지만(p<.05), 대퇴골 길이는 Sus집단과 Non집단 간 유의한 차이를 나타내지 않았다. 한편, DEXA법에 의한 전체 골밀도 및 pQCT법에 의한 피질골 골밀도는 Non집단을 BC집단과 비교할 때 각각 16%와 4% 정도 유의한 증가를 나타내었으나(p<.001), Sus집단은 증가하지 않았다. 이는 Sus집단이 Non집단 보다 각각 11%와 4% 정도 유의하게 낮음을 의미하는 것이다(p<.01). 또한, 골 단면적 및 피질골 두께, 골강도 지표인 SSI 등도 피질골 골밀도와 유사한 결과를 나타내었다(p<.01). 그러나 해면골의 골밀도는 각 집단 간 유의한 차이가 없었다. 혈청 Ca 농도 및 24시간 소변 Ca와 Dpd 배출량의 경우 집단 간 유의한 차이는 나타나지 않았으나 뒷다리 부유집단에서는 24시간 소변 P 배출량의 감소(p<.05)와 함께 혈중 P의 농도가 유의하게 증가되었다(p<.001). 이상의 결과에서 미세중력에 의한 골량감소는 해면골 보다는 주로 피질골에서 일어나고 있음을 의미하며, 이러한 골량감소는 P대사 이상에 의하여 유발될 가능성이 있음을 시사하는 것이다. To evaluate the osteopenia and the bone metabolism induced by microgravity, eighteen 7-week-old female Spraque-Dawley (SD) rats completed hindlimb suspension for 2-week. After a week of stabilization, rats were randomly divided into three groups: baseline controls group (n=6, BC), 2-week vivarium control group (n=6, Non) and 2-week suspension group (n=6, Sus). The BC, Non and Sus groups were fed standard lab chow (CRF-1, Charles river, JAPAN) to have same-volume-feeding in all groups. Before experimental period and after 2-week suspension, rats were sacrificed, and femurs were removed for analysis of bone mineral density (BMD) by dual energy X-ray absorptionmetry (DEXA, Lunar DPXL, USA) and peripheral quantitative computed tomography (pQCT, XC-960, Germany). The femoral fresh weight of the Sus group was decreased approximately in 8 % as compared to the Non group (p<.05), but the femoral length showed no change between the Non and the Sus group. On the other hand, BMD and cortical BMD of femur in the Non group were increased in approximately 16 and 4 % as compared with those of the BC group (p<.001), but those of the Sus group did not increased, and showed approximately 11 and 4 % lower than those of the Non group (p<.01). Similarly, the cortical cross-sectional area, bone thickness and stress-strain index (SSI), which reflect the mechanical strength, of cortical bone in the Non group significantly increased(p<.01, respectively), but those of the Sus group were significant lower than those of the Non group (p<.01 or p<.001). However, trabecular BMD did not show a significant difference among any groups. The serum calcium (Ca) concentration, urinary Ca and urinary deoxypyridinoline (Dpd) excretions between the Non and the Sus group showed similar levels. However, urinary phosphate (P) excretion of the Sus group dynamically decreased approximately 50% lower than that of the Non group (p<.05) while serum P concentration was increased (p<.001). These results suggest that the exposure to the microgravity environment induces spontaneous osteopenia in mainly cortical bone, and this osteopenia might be caused by disturbed P homeostasis.

흑미섭취와 트레드밀 운동이 흰쥐의 골밀도에 미치는 효과

김창선 ( Chang Sun Kim ),박동호 ( Dong Ho Park ),( Isao Kaneda ),( Shoji Igawa ) 한국운동영양학회 2005 Physical Activity and Nutrition (Phys Act Nutr) Vol.9 No.2

누가의 구원사

김창선(Chang-Sun Kim) 한국신약학회 2003 신약논단 Vol.10 No.2