나노/마이크로 압입 시험에 의한 플라즈마 세라믹 용사코팅의 특성 평가

최세영(Se-Young Choi),채영훈(Young-Hun Chae),김석삼(Seock-Sam Kim) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.36 No.-

The most controversial topics in plasma sprayed ceramic coating systems are recently mechanical properties such as bond strength, cohesive strength, toughness and so on. In this research, critical fracture load(Pc) and interface toughness(Ks) of four coatings materials were computed from the applied load, crack length and Young's modulus data which were measured by micro-vickers and nano indentation test. It is reasonable to consider the Pc value as comparison data of bond strength, and the Kc value, considering a trace of indent in the interface, was computed by a modified (E/H)I<SUP>½</SUP> ratio. In the case of the high loads (9.8N and 19.6N) in the Al₂O₃+13%TiO₂ coating, the critical point(Pco) at which the coating was broken was found. Also, used by a XRD phase analysis, we checked a change of coating' s properties, predicting a possible change of the phases in plasma sprayed coating.

나카가미 페이딩 체널에서 일반화된 선택성 다이버시티를 사용한 MPSK 신호의 평균 심벌 오류 확률

최세영,윤동원,한영열,Choi, Se-Yeong,Yoon, Dong-Weon,Han, Young-Yearl 대한전자공학회 1998 電子工學會論文誌, S Vol.s35 No.6

본 논문에서는 동일한 평균 전력을 가지며 주파수 비선택적 느린 나카가미 m-분포의 페이딩을 겪는 MPSK 신호들에 대한 다수의 다이버시티 가지 중 크기가 센 두세개의 신호를 순서대로 선택하고 합성하는 일반화된 선택성 합성 기법에 대한 평균 심벌 오류 확률식을 유도한다. 오류 확률식을 유도하기 위해 순서 통계량(Order Statistics)의 개념을 적용한다. 유도 과정에서 수신 신호의 확률 밀도 함수에 대한 새로운 전개가 소개되고 있으며, 다양한 수학적 기법들을 사용한다. 기존의 선택적 합성과 최대비 함성 기법과의 성능을 비교하여 적절한 다이버시티 가짓수를 찾는다. In this paper, a new closed form expression for the average symbol error rate(SER) of generalized selection combining(SC), whereby the two(three) signals with the two(three) largest amplitudes are combined from the original diversity branches in the channel, for MPSK signals in a frequency-nonselective slowly m-distributed Nakagami fading channel is derived. In order to analyze the error performance for a generalized SC, the Order-Statistics is applied. To derive the SER of MPSK signals with SC, the new expression of pdf is introduced and many other mathematical methods are used. Comparing the derived SER with that of MRC, we find adequate diversity branch number from total Lth-order diversity branches.

Arachidonic Acid Ingibits Norepinephrine Release through Blocking of Voltage-sensitive $Ca^{2+}$ Channels in PC12 Cells

최세영,박태주,최준호,김경태,Choi, Se-Young,Park, Tae-Ju,Choi, Jun-Ho,Kim, Kyong-Tai The Korean Society for Integrative Biology 1997 Korean journal of biological sciences Vol.1 No.1

We studied the mechanism of arachidonic acid on the secretion of a neurotransmitter in rat pheochromocytoma PC12 cells. Arachidonic acid inhibited the 70 mM $K^+$-induced secretion of norepinephrine. Arachidonic acid also inhibited the 70 mM $K^+$-induced $Ca^{2+}$ mobilization which is due to the opening of the voltage-sensitive $Ca^{2+}$ channels (VSCC). Both the half maximal inhibitory concentration ($IC_{50}$) of the norepinephrine secretion and VSCC coincided at 30 uM. The major oxidized metabolites of arachidonic acid, prostaglandins did not mimic the inhibitory effect of arachidonic acid. Nordihydroguaiaretic acid (NDGA) and indomethacin which are inhibitors of lipoxygenase and cyclooxygenase, respectively, did not block the inhibitory effect of arachidonic acid. The results suggest that arachidonic acid serves as a signal itself, not in the form of metabolites. The pretreatment of various $K^+$ channel blockers such as 4-aminopyridine, tetraethylarnmonium, glipizide, or glibenclamide also did not show any effect on the inhibitory effect of arachidonic acid. Through these results we suggest that arachidonic acid regulates VSCC directly and affects the secretion of neurotransmitters.

건물 자연환기구 개방 면적에 따른 풍량 및 냉방효과 분석

최세영(Choi, Se-Young),최정민(Choi, Jeong-Min) 한국건축친환경설비학회 2018 한국건축친환경설비학회 논문집 Vol.12 No.2

There are various of design techniques to reduce cooling load in building. Among them, the technique to use natural forces to drive outdoor air though a window to a space can be considered as an alternative. It can be divided into the buoyance-driven natural ventilation by indoor and outdoor temperature difference and wind-driven natural ventilation by outdoor wind power. Also, in multi-story building such as the atrium buildings, the air flow rate and temperature distribution of each zone greatly influenced according to opening related architectural design variables. Therefore, this study is carried out on the effect of openable area of outside window, indoor opening and roof opening on natural air ventilation rates and indoor temperatures under the buoyance-driven and wind-driven natural ventilation by using Coolvent program.

체중비 추정을 위한 BMI 비만 지수의 타당성

최세영(Se Young Choi),유성은(Seung Eun Yoo),고유선(You Sun Ko) 한국체육측정평가학회 2018 한국체육측정평가학회지 Vol.20 No.2

연구의 목적은 건강한 여대생을 대상으로 통상적으로 측정해온 체질량지수(body mass index: BMI)는 체중(kg)을 신장(m)의 제곱으로 나누어 산출되는 지수이지만, BMI는 지방을 측정하는 것이 아니라 무게의 척도라 생각되어 체중비를 다르게 나타내려한다. BMI는 단지 개인의 지방을 측정하기 위해서 사용되어져서는 안 된다. 체격지수가 비만지수로 사용되는데 있어서의 타당성을 알아보고자 한다. 이처럼 BMI는 지방을 측정하는 것이 아니라 무게의 척도라 할 수 있다. 단면적은 제곱에 비례하며, 부피(무게)는 세제곱에 비례하는데 산출 지수가 제곱이 아닌 세제곱에서 모든 경우의 정확도가 유의하다면 기존 지수의 정상범위 수치 또한 변화할 수 있을 것으로 보여 지며, 체중이 키에 제곱이 아닌 세제곱의 비만 지수를 제시 할 수 있다고 할 수 있다. BMI와 PI의 비교를 통하여 체격지수가 비만지수로의 활용가능성에 대한 타당성을 확인함으로써 사람 개인에 따라 혹은 집단에 따라서도 달라질 수 있으며, 체격지수에 대한 비만평가기준을 다르게 볼 수 있다. 이같이 유용성을 더한 BMI 비만 지수의 타당한 근거를 제시하고자 한다. 본 연구의 목적을 위하여 편의방식으로 표집 된 서울소재 일반 여자대학교 여대생 350명을 대상으로 측정하였으며, 불성실한 측정이나 설문지 누락된 부분을 제외한 총 304명의 자료를 사용하였다. 신체조성 중 신장은 직접측정 하였으며 몸무게는 분석기인 InBody 720(바이오페이스, KOREA)를 사용하여 체질량지수(body mass index: BMI)를 얻었다. 기존의 BMI지수와 세제곱으로 제시한 PI의 유사성과 연관성은 상관계수(r)에 의해 타당성 산출을 검정하였고, 변수와의 관계에서 얼마나 정확하게 추정 할 수 있는지 중다회귀분석을 이용하였다. SPSS 18.0 통계 프로그램을 이용하였으며, 유의 수준(α)은 .05로 하였다. The purpose of the study was to estimate body mass index (BMI), which is usually measured in healthy college students, by dividing body weight (kg) by the square of height (m).BMI is not a measure of fat but a measure of weight. At the study level, the weight gain is assumed to be mostly related to the increase in fat (Garrow &Webster, 1985) but not at the individual level. Therefore, BMI is not expected to be used only to measure an individual 's fat, and we want to see if it is valid for the body mass index to be used as an index of obesity. As such, BMI is not a measure of fat but a measure of weight. The cross-sectional area is proportional to the square, and the volume (weight) is proportional to the cube. If the accuracy is significant for all cases in the cube where the output index is not square, the normal range value of the existing index is also likely to change,We would like to present the obesity index of cu, not squared. A comparison of BMI and PI confirms the validity of the use of the BMI as an index of obesity. Thus, if the BMI can be changed according to individuals or groups, the criteria for the body mass index can be different. For the purpose of this study, 350 female college students at Seoul Normal University were sampled. The data were collected from 304 students except for the insufficient measurement and questionnaires missing. Body mass index (BMI) was measured using InBody 720 (BioPhase, KOREA).For relevance and similarity of BMI and PI, we used the correlation coefficient (r) to test the validity of the BMI index and the PI. The SPSS 18.0 statistical program was used and the significance level (α) was set to .05.

PCB mediated perturbation of Ion channel activities

Se-Young Choi(최세영) 환경독성보건학회 2014 한국독성학회 심포지움 및 학술발표회 Vol.2014 No.5

압입 시험에 의한 플라즈마 세라믹 용사코팅의 특성 평가

최세영(Se-Young Choi),채영훈(Young-Hun Chae),김석삼(Seock-Sam Kim) 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.35 No.-

The most controversial topics in plasma sprayed ceramic coating system are recently mechanical properties such as bond strength, cohesive strength, toughness and so on. Determination of bond strength of coatings is one of the most important problems. In the industry, the bond strength of coating system has been estimated by Pull-off test(ASTM standard C633-79), But, without a fixed jig and specimen, it is impossible to obtain the bond strength. Therefore, it is necessary to study the critical fracture load on interface of the coating by indentation test. Because the critical fracture load plays an important role in evaluating the bond strength for plasma sprayed ceramic coating system. So, we have estimated critical fracture load in plasma sprayed ceramic coating system, and it was shown that inverse relationship between the cross-section hardness of coating and the critical fracture load(Pc). In case of the high load(1㎏f, 2㎏f) in Al₂O₃+13%TiO₂, it was found that the critical point(Pco) which the coating was broken on.

30~50대 남녀 피부관리이용실태와 만족도에 관한 연구

최세영 ( Se-young Choi ),박효진 ( Hyo-jin Park ),이미정 ( Mi-jung Lee ),양지연 ( Ji-yeon Yang ),박은정 ( Eun-jung Park ),라원희 ( Won-hee La ),강유미 ( Yu-mi Kang ),조원정 ( Won-jung Cho ),김영희 ( Young-hee Kim ),김금란 ( Kum-lan 한국미용예술경영학회 2012 미용예술경영연구 Vol.6 No.1

The objective of this research is to find out actual conditions of use and satisfaction ratings of males and females from 30 to 50 years of age through questionnaires. The respondents had answered 30 pages of questionnaires from November 16thtol9thin2011, and 302 responses had been analyzed from November 28th to December 3rd in 2011. The data was analyzed using WIN SPSS 15.0. Frequency analysis is used find out the general characteristics of the respondents; Cronbach’ s a coefficient is used to check the reliability of each question; and One Way Anova is used to see the difference between males and females. There were 167 respondents in their 30s (56.3%), being the most populous age group, and the ratio of males and females were 50~50. 64.8% of the respondents were married; 64.6% were non-smokers; 61.3% did not exercise regularly; 56.3% used UV protection; 36.8% completed undergraduate education; 39.1% worked in professional fields; 33.8% earned less than 2,000,000 (KRW) per month; 61.6% invested less than 100,000 (KRW) in skin care. Females were more interested in skin care; both took care of their skin with high interests. There was no significant difference in satisfaction depending on the type of esthetics. Females in their 30s and males in their 40s and 50s preferred general esthetics, and this outcome is probably due to large differences among age groups. For medical esthetics, males showed higher satisfaction. There was no significant rise in satisfaction for franchise esthetics; females showed higher satisfaction. Satisfaction ratings for self-care varied upon the ability to deal with sanitation and information for skin care products; females show higher satisfaction. 52.3% chose 1 to 1.5 hours to be the most appropriate service length; 40.4% choose 30,000 (KRW) to be the most appropriate price; 68.5% were willing to visit professional esthetics.

환기구 면적 및 기상요소에 따른 자연환기량 평가에 관한 연구

최세영(Choi, Se-Young),최정민(Choi, Jeong-Min) 대한건축학회 2019 대한건축학회 학술발표대회 논문집 Vol.39 No.1

Natural ventilation through openings such as windows in buildings is an efficient resource for natural cooling during the intermediate season of the year. Because the natural ventilation uses the wind outside the building, the amount of ventilation will depend on the open area of the wall, the outside temperature, the wind speed, and the wind direction. The purpose of this study is to present the basic data on the open area of the intermediate season of the year by examining the effect of outdoor area temperature, wind speed, and the wind direction.

외상환자에서 수혈과 사망의 연관성

최세영 ( Se Young Choi ),이준호 ( Jun Ho Lee ),최영철 ( Young Cheol Choi ) 대한외상학회 2008 大韓外傷學會誌 Vol.21 No.2

Purpose: Using a propensity analysis, a recent study reported that blood transfusion might not be an independent predictor of mortality in critically ill patients, which contradicted the results of earlier studies. This study aims to reveal whether or not blood transfusion is an independent predictor of mortality in trauma patients. Methods: A total of three hundred fifty consecutive trauma patients who were admitted to our emergency center from January 2004 to October 2005 and who underwent an arterial blood gas analysis and a venous blood analysis were included in this study. Their medical records were collected prospectively and retrospectively. Using a multivariate logistic analysis, data on the total population and on the propensity-score -matched population were retrospectively analyzed for association with mortality. Results: Of the three hundred fifty patients, one hundred twenty-nine (36.9%) received a blood transfusion. These patients were older (mean age: 48 vs. 44 years; p=0.019) and had a higher mortality rate (27.9% vs. 7.7%; p<0.001). In the total population, the multivariate analysis revealed that the Glasgow coma scale score, the systolic blood pressure, bicarbonate, the need for respiratory support, past medical history of heart disease, the amount of blood transfusion for 24 hours, and hemoglobin were associated with mortality. In thirty-seven pairs of patients matched with a propensity score, potassium, new injury severity score, amount of blood transfusion for 24 hours, and pulse rate were associated with mortality in the multivariate analysis. Therefore, blood transfusion was a significant independent predictor of mortality in trauma patients. Conclusion: Blood transfusion was revealed to be a significant independent predictor of mortality in the total population of trauma patients and in the propensity-score-matched population. (J Korean Soc Traumatol 2008;21:108-114)