• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1011-1020
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• 2001

Volatile organic components from onions stored in the different decay conditions were extracted by SDE apparatus and analyzed by GC-FID and GC/MS. Components of 115, 143, 123 and 137 were identified in fresh onions, decayed onions without heating, half-decayed and complete-decayed onions after heating, respectively. These components included esters, aldehydes, ketones, alcohols and sulfur-containing compounds. Dimethyl trisulfide, dimethyl disulfide, dipropyl trisulfide and 3,5-diethyl-1,2,4-trithiolane were the main sulfur-containing components in fresh onions and decayed onions without heating. As spoilage of onions, the concentrations of sulfur-containing components of volatile extracts significantly decreased. Apart from sulfur-containing components, volatile organic components in half-decayed and complete-decayed onions after heating were mainly composed of esters, aldehydes, ketones and alcohols. Ketones of volatiles in complete-decayed onions after heating were high relatively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.1
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• pp.1-8
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• 2012

Numerical analysis has been carried out to investigate the fully developed flow and heat transfer characteristics of a plate heat exchanger. Multi-cell models with an inlet part and outlet part are used to perform the numerical simulation. The plate heat exchanger is characterized by a chevron angle of $20^{\circ}$ and a P/H ratio of 2.0~4.0. The working fluid is water and the Reynolds numbers range from 300 to 1,500. The correlation is given in the form of $f=CRe^m$ for the friction factor and $j=CRe^m$ for the Colburn factor. It is found that the fully developed flow starts from the third cell and the Nusselt number increases with decreasing P/H ratios.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.729-733
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• 2004

Tooth avulsion usually causes inflammatory root resorption and ankylosis, and ankylosis cause severe functional and esthetic problems, especially in childhood. A 7-year-old female visited the Dept. of Pediatric Dentistry, Yonsei University with the chief complaint of avulsive trauma to the upper right incisor which was left dry for 40 minutes. Tooth was irrigated with saline and replanted immediately and splinted. Anti bacterial agent and anti inflammatory agent were prescribed. After 4 months of replantation slight external root resorption and apical radiolucency was seen at radiographic examination, therfore pulp extirpation and calcium hydroxide($Vitapex^{TM}$) canal filling were carried out. After 16 months, root canal was filled with gutta-percha, and bleaching treatment was done. Treatment results were satisfactory both esthetically and functionally for 8 years and 5 months.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.269-275
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• 2002

미곡종합처리장 (RPC)에서 수행되고 있는 쇄미선별공정의 개선을 통해, 국내산 백미제품의 쇄립 혼입상태를 보다 더 정밀하게 관리하기 위한 기초 연구로서, 실험 결과를 바탕으로하여 국내 유통백미 제품의 등급판정에 사용할 수 있는 쇄립 기준을 결정하여 제시하였다. 연구결과를 요약하면 다음과 같다. 1. 백미제품 중의 쇄립 허용 혼입율에 관한 우리나라의 규격은, 일본백미 1등 표준품의 기준 및 미국백미 1등급 제품의 기준에 비견될 정도였지만, 쇄립의 정의 자체는 엄격하지 않았다. 또한, 미국과 일본과는 달리, 쇄립 혼입율 차이에 따른 백미 제품의 등급 체제가 존재하지 않았다. 이러한 사실을 종합하여 일본과 미국의 규격과 비교했을 때, 쇄미 혼입에 관한 한 우리나라는 매우 관대한 규격을 적용하고 있다고 판단된다. 2. 국내 유통백미 제품의 경우, 완전립 길이의 3/4 이상인 낟알들이 차지하는 중량 구성비는 93.5%였다. 완전립 길이의 $\frac{1}{4}$∼1/3, 1/3∼$\frac{1}{2}$, $\frac{1}{2}$∼2/3 및 2/3∼$\frac{3}{4}$에 해당하는 길이를 가진 낟알들의 중량비는 각각 0.3, 2.8, 2.7 및 0.6%이어서, 쇄립들의 길이는 2.5mm를 중심으로 주로 분포되어 있었다. 쇄립 혼입정도에 따른 국내 유통백미 제품의 등급은 한국과 일본의 기준을 적용할 경우, 쇄립의 총량 면에서는 만족할만한 수준이었다. 그러나, 한국의 잔싸라기 기준, 일본의 이물 함유비 기준, 미국의 6호체 통과분 기준이 적용될 경우, 국내 유통백미 제품의 등급은 매우 불량하였다. 3. 거의 모든 RPC에서는 쇄미선별설비로 로타리 시프터를 채택, 사용하고 있었으며, 로타리시프터 사용상의 문제는 회전몸체를 지지하는 rod spring의 파손 등 구조와 관련된 것이었다. 로타리 시프터에 의한 쇄립의 선별과 제거정도는 만족할 만한 수준은 아니었다. 4. 국내 유통백미 완전립의 길이, 폭, 두께는 각각 5.02mm, 2.93mm, 2.03mm이었으며, 산물밀도와 천립중은 각각 745.3kg/m3 및 20.46g이었다. 5. RPC 백미제품의 품질경쟁력 향상을 유도하고자 현행 쇄미의 정의와 기준을 보다 강화하여 다음과 같은 쇄미 기준과 계급을 설정, 제시하였다. "완전립" - 길이가 3.75mm이상인 미립 "준완전립" - 길이가 2.5∼3.75mm인 미립 "쇄미" - 길이가 1.75∼2.5 mm인 미립 "이물" - 길이가 1.75mm이하인 미립.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.296-304
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• 2001

배경: 이번 연구의 목적은 체내이식형 양심실 보조장치의 개발을 위한 안전하고 간편한 동물실험 모델을 확립하는 것이며 이동작동형 완전 인공심장의 양심실 보조장치로의 사용 가능성을 알아보는 것이다. 대상 및 방법: 7마리의 Corridale 양을 대상으로 실험하였다. 5번째 늑간극을 통하여 좌측 개흉술을 시행하고 좌측 유출로 캐뉼라는 하행 대동맥에 Dacron graft을 사용하여 연결하였고 유입로 캐뉼라는 좌심방에 삽입하였다. 우측 유출로 캐뉼라는 하행 대동맥과 같은 방법으로 주폐동맥에 연결하였으며 유입로 캐뉼라는 혜동맥을 하방으로 젖혀 우심방이를 노출시킨 다음 우심방이에 삽입하였다. 4마리에 있어서는 양심실 보조장치를 전복막강(preperitoneal space)에 위치시켰으며 2마리에 촤측흉강 내에, 1마리에서는 외부에 위치시켰다. aPTT는 수술전 aPTT의 2∼2.5배로 맞추어 주었다 결과: 수술중 또는 수술직후 사망한 경우는 없었으며 7마리 모두 인공호흡기 이탈이 가능하였고 스스로 기립하고 음식물 섭취도 가능하였다. 1마리는 술후 2일째 혈전 색전증 및 인공호흡기 작동 잘못으로 사망하였으며 2마리의 겨우는 술후 2일째 각각 양심실 보조장치의 작동 잘못 및 호흡부전으로 사망하였고, 3마리의 경우는 술후 4일째 혈전색전증으로 인한 급성신부전 및 호흡부전 등으로 사망하였다. 1마리에 있어서는 28일간 생존하였으며 양심실 보조장치의 구동 장치에 연결된 라인의 마로로 인해 양심실 보조장치의 작동이 정지되었으나 바로 양심실 보조장치를 제거하고 살릴 수 있었다. 모든 경우에 있는 캐뉼라를 삽입하고 양심실 보조장치를 작동시키는데 큰 어려움이 없었다. 7마리 중 4마리에서 혈전이 발견되었으며 특히 판막을 연결한 부위에 혈전생성이 많았다. 그러나 캐뉼라에는 혈전생성이 없었다. 결론: 양에 있어서 좌측 개흉술 및 전복막강 공간에 양심실 보조장치를 위치시키는 이번 동물실험 모델은 체내 이식형 양심실 보조장치 개발을 위한 좋은 동물실험 모델이라고 생각된다. 또한 디동 작동기형 완전 인공심장의 혈전생성을 억제할수 있는 방법들의 연구개발이 지속된다면 장기간의 체내 이식형 양심실 보조장치로 사용할 수 있을 것으로 생각된다.

• The Journal of the Acoustical Society of Korea
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• v.40 no.3
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• pp.213-218
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• 2021

It is known that total least-squares method shows better estimation performance than least-squares method when noise is present at the input and output at the same time. When total least squares method is applied to data with time series characteristics, Recursive Total Least Squares (RTS) algorithm has been proposed to improve the real-time performance. However, RTLS has numerical instability in calculating the inverse matrix. In this paper, we propose an algorithm for reducing numerical instability as well as having similar convergence to RTLS. For this algorithm, we propose a new RTLS using Iterative Wiener Filter (IWF). Through the simulation, it is shown that the convergence of the proposed algorithm is similar to that of the RTLS, and the numerical robustness is superior to the RTLS.

• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.26-34
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• 2022

The propulsion system of geostationary orbiting satellites is typically used to raise the orbit into a transfer orbit, maintain the orbital position in the south/north, east/west direction in regular operation, and accumulate momentum in the south/north and east/west direction. Recently, when an electric propulsion system is used in a geostationary orbit satellite, the payload capacity can be increased by about 40% compared to a chemical propulsion system. However, despite these advantages, using an electric propulsion system has several limitations that should apply to all geostationary orbiting satellites. This paper discusses the operational constraints to consider when developing an indigenous geostationary satellite using a fully electric propulsion, radiation exposure, and control mechanism design due to unit displacement and floating ground-design. A high-voltage control unit for electric drives were analyzed.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.1
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• pp.73-81
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• 2023

There are various approaches to treatment for patients with fully edentulous jaw. In maxilla, it is easy to obtain sufficient stability, support, and retention with the traditional full denture method. In mandible, however, there are difficulties caused by anatomical limitations. In this case, treatment with implants can be considered. If it is difficult to place implants in posterior area, a fixed complete denture can be considered, using 4 - 5 implants anterior to mental foramen. This approach has changed in many ways, such as surgical methods and materials used, over the years. This case report compares two approaches and their changes over time, especially in the cases of mandibular fixed prostheses using implants, paired with maxillary complete denture.

• The Journal of the Acoustical Society of Korea
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• v.42 no.3
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• pp.227-232
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• 2023

Underwater noise pollution has a significant impact on the marine environment. This study proposed a simple approach to estimate the acoustic radiation efficiency of structures with air bubble layers. The method considered the insertion loss caused by the air bubble layer through post-processing of numerical results, assuming that insertion loss is equivalent to attenuation as demonstrated by previous studies. The proposed approach was validated by comparing it with a fully coupled analysis for plate structure models. The commercial finite element program COMSOL Multiphysics was used for the acoustic-structure interaction analysis, and the acoustic characteristics of air bubble layer for the fully coupled analysis was simulated by on the Commander and Prosperetti theory. The trends indicated good agreement between the simple approach and the fully coupled analysis in terms of radiation efficiency. It is confirmed that the proposed method is providing insight into the principal mechanism of underwater noise reduction for the bubble layer on the wedge-shaped structure.

• Journal of Chest Surgery
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• v.32 no.7
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• pp.628-636
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• 1999

Background: Recent advances in understanding the anatomy of the complete atrioventricular septal defect(including right-dominant unbalanced atrioventricular septal defect) have led to alternative methods of repairing these defects. Material and Method: From May 1997 to July 1998, 8 consecutive infants(age range, 2 to 28 months, mean body weight 6.0$\pm$2.2 kg) received a single-stage intracardiac repair of the complete atrioventricular septal defect with modified surgical methods. Depending on the specific anatomic structure, the procedure was simplified in 3 patients by a direct closure of the ventricular element of the defect(Group I). Two patients judged unsuitable for direct closure due to a potential left ventricular outflow tract obstruction had received a standard two-patch repair(Group II). The remaining 3 patients with right-dominant unbalanced complete atrioventricular septal defect underwent biventricular repair; to enlarge the orifice of the left atrioventricular valve, the ventricular septal patch was placed slightly more to the right of the ventricular crest, a left sided bridging leaflet was augmented with an autologous pericardial patch, and the leaflet was repaired with a double- orifice(Group III . Result: In all 8 patients, the postoperative echocardiography demonstrated good hemodynamics. Seven patients were weaned from the ventilators after a mean 3$\pm$1 days, and 1 patient was weaned after 24 days due to a reoperation and emphysematous lung problem. A reoperation was performed in 1 patient for progressive left atrioventricular valve regurgitation due to leaflet tearing. There were no early and late mortalities. At the time of the latest review, judging from the echocardiographic criteria, left atrioventricular valve stenosis was mild in 1 patient(mean pressure gradient 6.5 mmHg, 13.5%), left atrioventricular valve regurgitation was absent or grade I in 7 patients(87.5%). The right atrioventricular valve regurgitation was absent or grade I in all 8 patients(100%). Conclusion: Infants with complete atrioventricular septal defect were treated with either a simplified approach with direct closure of the ventricular element of the defect or a modified surgical technique for a right-dominant unbalanced atrioventricular septal defect, depending on the anatomic structure. The results were no operative mortalities and low morbidity.