강성기초의 3차원 동적 경계요소해석

이찬우,김문겸,황학주,Lee, Chan Woo,Kim, Moon Kyum,Hwang, Hak Joo 대한토목학회 1993 대한토목학회논문집 Vol.13 No.5

본 연구에서는 강성기초의 동적응답을 얻기 위해서 비완화 경계조건(non-relaxed boundary condition)을 적용한 3차원 경계요소를 사용하였다. 경계요소는 장래의 비선형문제의 확장을 위해서 시간영역에서 형식화되었으며 기본해는 무한영역의 Stokes 해를 사용하였다. 본 연구는 검증되었으며 지반기초 및 임의 형상의 지하구조물외 동적응답을 얻는데 이용할 수 있다. In this work the dynamic response of 3-D arbitrarily shaped rigid massless foundation is numerically obtained using boundary element under non-relaxed boundary condition. The problem is formulated in time domain by the boundary element method. The fundamental solutions used in this work are the Stokes solutions of the three dimensional elastodynamics. This method has advantages over frequency domain techniques in that it provides in a natural and direct way the time history of the response and forms the basis for elct:ension to nonlinear problems. This work is verified and can be used for practical purpose.

선박의 초기설계 제품정보관리를 위한 PLM 시스템 원형 개발

이찬우,이장현,이경호,이재범,김대석,서흥원,Lee, Chan-Woo,Lee, Jang-Hyun,Lee, Kyung-Ho,Lee, Jae-Beom,Kim, Dae-Seok,Seo, Heung-Won 한국전산구조공학회 2008 한국전산구조공학회논문집 Vol.21 No.6

최근의 제조 산업에서 제품개발 정보는 제품 수명주기 관리(PLM: Product Lifecycle Management) 시스템을 통하여 관리하고, 조달과 생산 계획에 관련된 통제는 전사적 자원관리(ERP: Enterprise Resource Planning), 생산 관리 시스템이 담당하고 있다. 특히, 효율적인 제품 개발과 시스템 구축 여부는 설계 및 생산, 원가 관리 전체에 걸쳐 영향을 미친다. 따라서 도면, 모델, 자재 정보 등 제품정보관리를 위한 PLM시스템의 역할이 매우 중요하게 여겨지고 있다. 이러한 PLM체계는 요구 사항 분석, 시스템 설계 그리고 기존 Data Migration 등 정보 시스템 개발 절차를 따라서 수행된다. PLM시스템은 전사적인 시스템 개발 과정에서 Prototype개발을 진행하여 구축 절차와 체계 설계를 검증하는 것이 효과적이다. 이 과정에서 PLM 아키텍처 및 제품 구조(Product Structure) 구성, PLM의 기능 개발을 수행한 후에 전체 시스템 설계 개발을 재 수행하는 것이 효과적이다. 본 연구에서는 조선 PLM구축에 필요한 절차와 체계 설계 방법을 제시하고, 이를 초기 기본 설계 단계에 적용하여 PLM구축 방법론을 제시하고자 한다. 초기 설계를 대상으로 요구사항을 도출하고, PLM의 아키텍처를 설계하였으며, 설계한 시스템을 Prototype형태로 제시하였다. Shipbuilding is a kind of ETO(Engineering To Order) industry which designs and produces a product in accordance to various requirement of customers, rules and regulations. Recently, the number of ordered ships has been increased by up to two or three times in each domestic shipyards. Most shipyards have been adopted 3D ship CAD, ERP(Enterprise Resource Planning) and APS(Advanced Planning System) to get an efficient product development and manufacturing system. However, not only the effective operation of 3D ship CAD, ERP and APS but also the production efficiency can be achieved only if product information management which can manages the product data is implemented in an integrated environment. Present study has suggested a systematic approach to implement a PLM system to manage the product data in early design shipbuilding. Also, a prototype of PLM is implemented to manage the product data in a basic ship-design. In the prototype system, a product structure and architecture of PLM is considered.

FEM해석 기반 스퍼기어 펌프의 실험적 검증에 대한 연구

이찬우,김상유,이서한,김재열,임진혁,Lee, Chan-Woo,Kim, Sang-Yu,Lee, Seo-Han,Kim, Jae-Yeol,Lim, Jin-Hyuk 한국기계가공학회 2022 한국기계가공학회지 Vol.21 No.6

This work investigated the performance improvement of a medium-pressure fixed-displacement-type SPUR gear pump, which is mainly used in the machine tool industry. The 3D CFX analysis and IS technique were applied using ANSYS (commercial FEM code) and compared with experimental results to ensure the reliability of the analysis. In addition, the performance improvement of the pump was obtained using the theoretical volumetric displacement equation, and the gear tooth width was changed. The pressure flow performance curves were compared, and the results were analyzed according to the width of the gear teeth. This is a factor that can cause irregular flow, vibration, and noise inside the gear pump owing to friction between the housing and gear pump.

CFD해석을 활용한 기어펌프 하우징 간격에 따른 성능 분석

이찬우(Chan-woo Lee),김재열(Jae-yeol Kim),이성준(Seong-jun Lee),김상유(Sang-yu Kim),이서한(Seo-han Lee),고정민(Jeong-min Ko),임진혁(Jin-Hyuk Lim) 한국자동차공학회 2021 한국자동차공학회 학술대회 및 전시회 Vol.2021 No.11

MPD 값의 변화로 평가한 UVA 정률적 증량법에서의 건선 PUVA 요법의 치료효과

이찬우(Chan Woo Lee),김영훈(Young Hun Kim),이병건(Byoung Gun Lee),송기훈(Ki Hoon Song),김기호(Ki Ho Kim) 대한피부과학회 2002 大韓皮膚科學會誌 Vol.40 No.9

N/A Background: The PUVA therapy of psoriasis is a very effective therapeutic modality that combines the action of light and drugs. Generally the conventional PUVA therapy based on patients skin type is used in Korea. But there are many reported that conventional PUVA therapy is not suitable in several instances including the determination of oral 8-methoxypsoralen(8-MOP) dose, initial and incremental UVA dose and so on. Objective: The purpose of this study is to establish a new protocol of PUVA therapy that is photomedically acceptable, Method: From 1997 to 2001, twenty psoriasis patients of moderate to severe grade who visited our clinic, were treated with PUVA therapy. Initial UVA dose was the same as MPD of each patient and proportion of weekly incremental UVA dose was 20% added to previous dose. All patients received PUVA therapy twice a week. The 8-MOP dose was determined by body surface area. Result: Total of 8 patients were skin type III, and 12 patients were skin type IV, The average of initial MFD in skin type III was 1.75J/㎠(0.5~2,5J/㎠) and skin type IV was 3.25J/㎠ (2.5~4.5J/㎠). The average number of treatments to the end of therapy were 13.63(10~16) in skin type III, and 12.5(8~18) in skin type IV. The total cumulative UVA dose was 44.73J/㎠ (30~68.2J/㎠) in skin type III, and 67.9SJ/㎠ ((31.6~109J/㎠) in skin type IV. Conclusion: The excellent effectiveness and safety of our new PUVA protocol have been demonstrated. We conclude that this FUVA protocol is a very effective, safe, and efficient method for the treatment of psoriatic patients. (Korean J Dermatol 2002;40(9): 1083~1088)

한국형 고속열차의 터널부 궤도 트랙에 따른 횡진동 특성분석

이찬우(Chan Woo Lee),김대상(Dae Sang Kim),김재철(Jae Chul Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

본 논문은 상업운행 중에 있는 한국형고속열차의 터널부에서의 횡진동 특성을 분석한 것이다. 한국형 고속열차가 운행되는 터널 부 궤도트랙은 콘크리트궤도와 자갈궤도로 되어 있다. 열차가 터널부를 통과 시에 열차 속도에 증가하면 횡진동 값도 거의 비례하여 증가하는 특성을 보여준다. 열차속도가 300㎞/h 정도에 근접하면 차체 측벽에서의 횡진동 값은 96 에서 107㏈(A) 정도를 나타낸다. 이때 차체 횡진동 값에 크게 영향을 주는 것은 터널 부 궤도트랙의 종류에 따라 다르게 나타나는데, 자갈궤도 보다 콘크리트궤도에서 차체 횡진동 값이 크게 나타난다. 이 값은 약 2 ? 3㏈(A) 정도이다. This paper deals with the status of the lateral acceleration of the KTX vehicles during the commercial operation in tunnels. Lateral vibration levels are measured in a vehicle while it is passing through tunnels and the results are compared with those measured on a slab track and a ballasted track. Lateral vibration level increases steadily as the train speed increases. Lateral vibration level of carbody side wall ranges from 96 to 107㏈(A) when the velocity is above 300㎞/h. It is noticeable that the lateral vibration level the slab tunnel is larger than that of the ballasted track. The differences are approximately 2-3㏈(A).

갑상선환자에서의 5분 99mTc - Pertechnetate 섭취율과 방사성옥소섭취율의 상관관계

이찬우(Chan Woo Lee),원규장(Kyu Chang Won),윤현대(Hyun Dae Yoon),조인호(In Ho Cho),김태년(Tae Nyeun Kim),신동구(Dong Gu Shin),이형우(Hyoung Woo Lee),심봉섭(Bong Sup Shim),이현우(Hyun Woo Lee) 대한핵의학회 1992 핵의학 분자영상 Vol.26 No.2

N/A The 20-minute Tc-99m-pertechnetate uptake became readily available for routine use and it replaced 131I for thyroid imaging. However measuring thyroid uptake during a 5-minute minimizes pertechnetate uptake by the salivary glands and presence of contaminated saliva from those glands in to the pharynx and esophagus. A study was carried out to determine the suitability of the utility of a 5-minute and 20-minute interval from administration of Tc-99m-pertechnetate to imaging and uptake measurement as a replacement for the 24 hour standard originally established with 131I, and to evaluate the relationship between 5-minute Tc-99m-pertechnetate uptake and other thyroid functions. A 5-minute and 20-minute uptake of Tc-99m-pertechnetate were measured in 70 patients with thyroid disease at Yeungnam University Hospital from March 1, 1991 to Feb. 29, 1992. The results were as follows. 1) The 5-minute Tc-99m-pertechnetate uptake in Graves' disease, Hashimoto's thyroiditis, simple goiter non toxic nodular goiter, subacute thyroiditis and euthyroid were 18.2%, 14.6%, 2.8%, 3.2%, 1.2% and 1.1%, respectively. There was a significant difference between the mean of the euthyroid group and the mean of the Graves' disease. So differenciation between them can be easily made. 2) The 5 minute Tc-99m- pertechnetate thyroid uptake was well correlated with 24 hour 131I thyroid uptake (r=0.75, p〈0.001). These data provided an equation for estimating the 24 hour uptake of iodide given the 5 minute pertechnetate uptake: Estimated 24-hour 131I thyroid Uptake = 7.188*ln (5 minute Tc-99m- Pertechnetate uptake)+16.94 3) The 20-minute Tc-99m-pertechnetate thyroid uptake was well correlated with 24-hour 131I uptake (r=0.72, p〈0.001) and 5-minute Tc-99m-pertechnetate thyroid uptake (r=0.96, p〈0.001). 4) In the Graves' disease, The 5-minute Tc-99m-pertechnetate thyroid uptake was well correlated with serum T3-resin uptake (r=0.46, p〈0.01), serum total T3 (r=0.55, p〈0.05), serum total T4 (r=0.46, p〈0.05). These results suggest that 5-minute Tc-99m- pertechnetate thyroid uptake has been found at least as useful as 24-hour 131I uptake for diagnostic confirmation at our hosptial, the logistical advantages of completing the diagnosis. The exam in 5-minutes led us to abandon the 24-hour study in the majority of patients, but the 24-hour 131I uptake is still obtained in patients with planned or potential radioiodine therapy.

KTX 영업속도 360km/h을 위한 기술적 도전 : 소음

이찬우(Chan-Woo Lee),김재철(Jae-Chul Kim),김대상(Dae-Sang Kim) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.10

건선 관절염 환자에서 동반된 대퇴골두의 무혈성 괴사

박찬수 ( Chan Su Park ),서우종 ( Woo Jong Seo ),조영재 ( Yeong Jae Cho ),차경우 ( Kyeung Woo Cha ),이찬우 ( Chan Woo Lee ),오동호 ( Dong Ho Oh ),김태권 ( Tae Gwun Kim ),민복기 ( Pok Kee Min ),김도원 ( Do Won Kim ),장윤환 ( Yun Hwa 대한류마티스학회 2003 대한류마티스학회지 Vol.10 No.3

Psoriatic arthritis and avascular necrosis of the femoral head each are relatively common diseases. However, avascular necrosis of the femoral head in psoriatic arthritisis extremely rare disease and a few cases have been reported to date. It is suggested that the use of steroids or chemotherapeutic agents, hyperuricemia, alcohol abuse, immunologic disorders, coagulopathies are risk factors of the development of avascular necrosis of the femoral head in psoriatic arthritis. This report describes a 58-year-old female patient without any of forementioned risk factors who underwent total hip replacement for femoral head avascular necrosis associated with psoriatic arthritis.

감귤 추출물의 미백효능 및 항산화 효능에 관한 연구

김한성 ( Han Sung Kim ),이찬우 ( Chan Woo Lee ),김덕희 ( Duck Hee Kim ),김기옥 ( Gi Ok Kim ),김세재 ( Se Jae Kim ),장이섭 ( Ih Seop Chang ) 대한화장품학회 2007 대한화장품학회지 Vol.33 No.2

본 연구에서는 제주도 자생 감귤 17종에 대하여 탈색소효과(depigment effect)를 연구하였다. B16 멜라닌 생성세포(B16 melanoma cell)를 이용하여 tyrosinase 및 멜라닌 생성억제 효과를 연구한 결과 대조군 대비하여 농도 의존적으로 감소하는 3종의 미성숙 온주밀감(immature Citrus unshue), 팔삭(Citrus hassaku), 진지향(Citrus sinensis x reticulata)을 도출하였다. 또한, 이와 같이 도출된 감귤 추출물을 이용하여 멜라닌 세포 생성(melanogenesis)에 영향을 미치는 tyrosinase, DOPAchrome tauto-merase (TRP-2)와 DHICA oxidase (TRP-1) 단백질 발현을 실험한 결과 tyrosinase, TRP-1, TRP-2 단백질 발현이 감소함을 나타내었다. 특히 이들 중 미성숙 온주밀감은 tyrosinase와 TRP-1 단백질 발현에서 유의적으로 감소하는 결과를 보였다. 본 연구 결과로써 미성숙 온주밀감은 모든 실험에서 우수한 효과를 나타내어 UV에 의해서 야기되는 피부 색소 침착을 방지할 수 있는 물질로서 기대할 수 있다. We examined the depigmentation effect on Korean traditional citrus 17 species. With B16 melanoma cells, we have seen inhibition of the tyrosinase and melanin formation, which eventually were dose dependently decreased by three citrus fruits, immature Citrus unshiu, Citrus hassaku, and Citrus sinensis × reticulata as compared with positive control. Also, we examined expression of tyrosinase, DOPAchrome tautomerase (TRP-2), and DHICA oxidase (TRP-1) which affect melanin synthesis. Especially, immature Citrus unshiu decreased the protein levels of tyrosinase and TRP-1. In conclusion, immature Citrus unshue showed the strongest activity in all the experiments mentioned above and we expect that it can be used for preventing UV-induced pigmentation.