• Title/Summary/Keyword: 고정희

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Numerical Study of the Rib Arrangements for Enhancing Heat Transfer in a Two-pass Channel of Large Aspect Ratio (종횡비가 큰 이차유로에서 냉각성능 향상을 위한 요철배열 연구)

  • Han, Sol;Choi, Seok Min;Sohn, Ho-Seong;Cho, Hyung Hee
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.3
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    • pp.161-169
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    • 2017
  • The present study investigated the effect of the rib arrangement and a guide vane for enhancing internal cooling of the blade. Two types of rib arrangements were used in the first and second passage in parallel. Aspect ratio of the channel was 5 and a fixed Reynolds number based on hydraulic diameter was 10,000. The attack angle of rib was $60^{\circ}$, rib pitch-to-height ratio (p/e) was 10, and the rib height-to-hydraulic-diameter ratio ($e/D_h$) was 0.075. The effect of an interaction between Dean vortices and the secondary vortices from the first passage was observed. Overall, the attack angle of rib in the first passage was dominant factor to heat transfer and flow patterns in turning region. Also, the channel with a guide vane showed enhanced heat transfer at the tip surface with reducing flow separation and recirculation.

Molecular diagnosis of Niemann-Pick type C presenting with neonatal cholestasis and hepatosplenomegaly (지속되는 신생아 담즙 정체증과 간비비대를 주소로 내원하여 유전자분석으로 확진된 C형 Niemann-Pick병)

  • Jeong, Min-Hee;Ko, Jung-Min;Kim, Gu-Hwan;Yoo, Han-Wook
    • Journal of Genetic Medicine
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    • v.4 no.2
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    • pp.200-203
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    • 2007
  • Niemann-Pick type C is an inborn error of metabolism that affects lipid degradation and storage, which is characterized by hepatosplenomegaly and progressive neurological symptoms. A 7-month-old girl with jaundice was presented cholestasis and hepatosplenomegaly. Laboratory study showed elevated acid phosphatase, angiotensin converting enzyme and mild decrease of cholesterol. Characteristic foamy cell and sea-blue histiocytes in bone marrow biopsy consistent with Niemann-Pick disease. Niemann-Pick type C was suspected by past medical history and findings of physical examination. Therefore, molecular analysis was performed and found mutations of NPC1 gene. We report the first Korean case of type C Niemann-Pick disease confirmed by mutation analysis.

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Structure Test and Vibration Analysis for Small Aircraft (소형항공기(반디호) 몰드의 구조시험 및 진동해석)

  • Jung, Do-Hee;Kim, Jin-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.692-697
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    • 2005
  • A canard type aircraft, which has good wing stall and stall/spin proof characteristics, is being developed. The previous first and second prototypes, having full depth core sandwich type wing and fixed landing gear, was built for test flights. Newly developing Firefly will be equipped with retractable landing gear and conventional foam core sandwich laminate for wing and fuselage. For manufacturing, composite material process has been studied including coupon tests. Wet lay-up onto foam core with glass fabric using lay-up mold has been chosen, and composite material parts are cured under room temperature and atmospheric pressure condition. In general, molded parts show so good surface smoothness and standardized quality that are best in mass production. In this study, we present the mold technology and development status for small aircraft firefly.

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Comparison of nitrogen removal efficiency on process stability for granular and immobilized anammox bacteria (공정 안정성에 대한 입상 및 고정화 혐기성 암모늄 산화균의 질소제거효율 비교)

  • Choi, Daehee;Bae, Hyokwan;Jung, Jinyoung;Kim, Sang-Hyoun
    • Journal of Korean Society of Water and Wastewater
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    • v.28 no.2
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    • pp.195-206
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    • 2014
  • Immobilization of anaerobic ammonium oxidizing bacteria has been studied to enhance the biomass retention of the slowly growing bacteria and the process stability. The purpose of this study was to compare the nitrogen removal efficiency of granular and immobilized anammox bacteria with poly vinyl alcohol and alginate. The specific anammox activity of the granular, homoginized and immobilized anammox bacteria were $0.016{\pm}0.0002gN/gVSS/d$, $0.011{\pm}0.001gN/gVSS/d$ and $0.007{\pm}0.0005gN/gVSS/d$, respectively. Although the activity decreased to 43.7 % of the original one due to low pH and $O_2$ exposure during the homogination and the immobilization, it was rapidly recovered within 7 days in the following continuous culture. When synthetic T-N concentrations of 100, 200, 400, 800 mg/L were fed, the immobilized anammox bacteria showed higher nitrogen removal efficiencies at all operational conditions than those of granular anammox bacteria. When the sludge retention time was shorten below 30.7 days and the reject water was fed, the nitrite removal efficiency of the granular anammox bacteria dropped to 8 % of the initial value, while that of the immobilized anammox bacteria was maintained over 95 % of the initial one. The immobilization with poly vinyl alcohol and alginate would be a feasible method to improve the performance and stability of the anammox process.

Influence of the Substrate Temperature on the Characterization of ZnO Thin Films (기판온도가 ZnO 박막의 특성에 미치는 영향)

  • Joung, Yang-Hee;Kwon, Oh-Kyung;Kang, Seong-Jun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.12
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    • pp.2251-2257
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    • 2006
  • We fabricated ZnO thin film successfully by using RF magnetron sputtering and investigated its potential for being utilized as the key material of piezoelectric device with the characterization of ZnO thin film such as such as crystallinity, surface morphology, c-axis orientation, film density. In thin study, $Ar/O_2$ gas ratio is fixed 70/30, RF power 125W, working pressure 8mTorr, distance between substrate and target 70mm, but the substrate temperature is varied from room temperature to $400^{\circ}C$. The relative intensity ($I_{(002)}/I_{(100)}$) or (002) peak in ZnO thin film deposited at $300^{\circ}$ was exhibited as 94%, then its FWHM was $0.571^{\circ}C$. Also, from the surface morphology evaluated by SEM and AFM, the film deposited at $300^{\circ}C$ showed uniform particle shape and excellent surface roughness of 4.08 m. The tendency of ZnO thin film density was exhibited to be denser with increasing substrate temperature but slightly decreased at near $400^{\circ}C$.

Influence of substrate temperatures on optical and electrical properties of ZnO:Al thin films (기판온도가 AZO 박막의 광학적 및 전기적 특성에 미치는 영향)

  • Chung, Yeun-Gun;Joung, Yang-Hee;Kang, Seong-Jun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.1
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    • pp.115-120
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    • 2009
  • The 3wt.% Al-doped zinc oxide (AZO) thin films were fabricated on Coming 1737 substrates at a fixed oxygen pressure of 200 mTorr with various substrate temperatures ($100\;{\sim}\;250^{\circ}C$) by using pulsed laser deposition in order to investigate the microstructure, optical, and electrical properties of AZO thin films. All thin films were shown to be c-axis oriented, exhibiting only a (002) diffraction peak. The AZO thin film, fabricated at 200 mTorr and $250^{\circ}C$, showed the highest (002) orientation and the full width at half maximum (FWHM) of the (002) diffraction peak was $0.44^{\circ}$. The optical transmittance in the visible region was higher than 85 %. The Burstein-Moss effect, which shifts to a high photon energy, was observed. The electrical property indicated that the highest carrier concentration ($3.48{\times}10^{20}cm^{-3}$) and the lowest resistivity ($1.65{\times}10^{-2}{\Omega}cm$) were obtained in the AZO thin film fabricated at 200 mTorr and $250^{\circ}C$.

Unusual Behavior Detection of Korean Cows using Motion Vector and SVDD in Video Surveillance System (움직임 벡터와 SVDD를 이용한 영상 감시 시스템에서 한우의 특이 행동 탐지)

  • Oh, Seunggeun;Park, Daihee;Chang, Honghee;Chung, Yongwha
    • KIPS Transactions on Software and Data Engineering
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    • v.2 no.11
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    • pp.795-800
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    • 2013
  • Early detection of oestrus in Korean cows is one of the important issues in maximizing the economic benefit. Although various methods have been proposed, we still need to improve the performance of the oestrus detection system. In this paper, we propose a video surveillance system which can detect unusual behavior of multiple cows including the mounting activity. The unusual behavior detection is to detect the dangerous or abnormal situations of cows in video coming in real time from a surveillance camera promptly and correctly. The prototype system for unusual behavior detection gets an input video from a fixed location camera, and uses the motion vector to represent the motion information of cows in video, and finally selects a SVDD (one of the most well-known types of one-class SVM) as a detector by reinterpreting the unusual behavior into an one class decision problem from the practical points of view. The experimental results with the videos obtained from a farm located in Jinju illustrate the efficiency of the proposed method.

Major Characteristics of Hordeum bulbosum and Haploid Production of Cultivated Barley by Pollinating with H. bulbosum L. (야생보리(Hordeum bulbosum)의 주요 특성 및 이를 이용한 보리 반수체육성)

  • 정동희;민경수;천종은
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.38 no.6
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    • pp.531-536
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    • 1993
  • Bulbosum method, which haploids are developed by pollinating with H. bulbosum have been productive to be recommended as an effective method for the production of genetically stable normal barley hybrids. The purpose of this study is to investigate several characters of H. bulbosum, seed set and embryo development rate pollinated with H. bulbosum in order to establish a method for improvement of embryo development and to find conditions favoring plant development from the embryos cultured in vitro. Three lines of H. bulbosum used as pollinators: GBC(2${\times}$), Spenish diploid(2${\times}$) and var. Jaaska (4${\times}$) were morphologically similar, having characteristically narrow leaves, narrow and long culms, long spikes and anthesis duration in comparison with H. vulgare. H. bulbosum, var. Jaaska(4${\times}$) on being pollinated to barley cultivars, increased embryo formation by 8% and plant development in vitro by three times compared to the other diploid lines. the plants developed were not normal barley hybrids but had some H. bulbosum chromosomes uneliminated, indicating that the line was unstable as a pollinator to induce barley haploids.

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3차원 치료계획용 전산화단층촬영에서 영상증강을 위한 최적의 프로토콜에 관한 연구

  • 이상규;이석;김주호;백종걸;조정희;신동봉;박재일
    • The Journal of Korean Society for Radiation Therapy
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    • v.14 no.1
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    • pp.15-22
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    • 2002
  • 1. 목적 : 방사선종양학과에서 3차원 치료계획용 전산화단층촬영 시 조영제 주입율에 따른 CT 값(hounsfield unit, H.U) 변화를 정량적으로 평가하여 최적의 영상증강효과 및 방사선치료계획을 위한 기초 프로토콜을 제시하고자 한다. 2. 대상 및 방법: 연세암센터 방사선종양학과에서 3차원 치료계획용 전산화단층촬영을 시행한 상복부(폐암)환자 20명을 대상으로 하였다. 조영제 양(130mL)은 일정하게 고정하였고, 조영제주입율을 1.2, 1.5, 2.0 mL/sec로 변화시켜가며 조영제를 주입하면서 3차원 방사선치료계획영상에 적합한 조영제주입율(contrast flow rate)과 지연시간(delay time)을 도출하였고, CT 값을 측정하여 정량적 평가를 시행하였다. 관심부위는 폐동맥과 폐정맥으로 하였다. 그리고, 환자 기본정보, 조영제주입율, H.U 등 영상증강에 영향을 미치는 인자들을 통계처리 프로그램인 SPSS를 이용하여 최적의 영상을 획득할 수 있는 기초 프로토콜을 작성하였다. 3. 결과 : 폐암환자의 전산화단층촬영영상 획득 시 3차원 방사선치료계획에 적합한 영상을 얻을 수 있는 조건중 조영제주입율은 1.5 mL/sec 이었고, 지연시간은 $60{\sim}70$초이었다. 통계처리를 수행한 결과 환자의 기본정보 및 조영제주입율 등이 영상증강에 영향을 미치는 인자임을 알 수 있었다. 본 연구에서 작성한 기초 프로토콜을 이용하여 3차원 방사선치료계획 시 정확한 종양 및 정상조직 설정이 용이하게 되어 방사선치료 효율을 극대화 할 수 있었다. 4. 결론 : 방사선종양학과에서 3차원 치료계획용 전산화단층촬영 시 사용할 수 있는 기초적인 영상획득 프로토콜을 도출하였고, 향후 더 많은 임상경험과 정량적 평가가 수반된다면 임상에 적극 사용할 수 있을 것이라 사료된다.

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Structural Optimization for a Jaw Using the Kriging model (이단계 크리깅 모델을 이용한 조(Jaw)의 구조최적설계)

  • Lee, Kwon-Hee;Bang, Il-Kwon;Kang, Dong-Hun;Han, Dong-Seop;Han, Geun-Jo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.143-147
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    • 2006
  • The rail clamp is the device to prevent that a crane slips along rails due to the wind blast as well as locate the crane in the set position for loading and unloading containers. The wedge type rail clamp should be designed to consider the structural stability and the durability because it compresses both rail side with large clamping force by the wedge working as the wind speed increases. In this research, the kriging interpolation method using sequential sampling is utilized to find the optimum shape of the jaw in the rail clamp. The suggested method predicts more accurate response value than the response surface method. The optimum results obtained by the proposal method are compared with those by the commercial software.

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