Space holder 방법으로 제조된 다공질 타이타늄의 기계적 성질에 대한 Computed-Tomography를 이용한 유한요소해석

이동준,안동현,이병갑,정지원,오상호,이종수,김형섭,Lee, Dong Jun,Ahn, Dong-Hyun,Lee, Byounggab,Jeong, Jiwon,Oh, Sang Ho,Lee, Chong Soo,Kim, Hyoung Seop 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.5

In this study, porous titanium samples were manufactured by space holder methods using two kinds of urea and sodium chloride space holders. Three-dimensional pore structures were obtained by a computed-tomography (CT) technique and utilized for finite element analysis in order to investigate the mechanical properties. The CT-based finite element analyses were in better agreement with the experimental results than unit cell model-based analyses. Both the experimental and CT-based results showed the same tendency that the elastic modulus decreased with increasing the porosities. The total porosity of the bulk body plays a key role in determining the elastic modulus of porous materials.

동강의 어류상과 생태학적 군집분석

최준길 ( Jun Kil Choi ),오사무미타무라 ( Osamu Mitamura ),이동준 ( Dong Jun Lee ),신현선 ( Hyun Seon Shin ) 한국환경생태학회 2008 한국환경생태학회지 Vol.22 No.6

2006년 5월부터 2007년 5월까지 동강의 어류상과 생태학적 군집분석을 조사한 결과는 다음과 같다. 조사된 어종은 총 10과 31종이었다. 총 31종의 어종 중 일차담수어가 26종, 주연성 담수어가 5종으로 나타나 일차담수어의 구성비가 매우 높았다. 우점종은 참갈겨니(Zacco koreanus) 55.73%, 아우점종은 쉬리(Coreoleuciscus splendidus) 7.15%였으며, 우세종은 배가시리(Microphysogobio longidorsalis) 6.12%, 어름치(Hemibarbus mylodon) 4.87%, 참종개(Iksookimia koreensis) 4.49% 등이었다. 한국고유종은 묵납자루(Acheilognathus signifer), 줄납자루(A. yamatsutae), 가는돌고기(Pseudopungtungia tenuicorpus), 쉬리(C. splendidus), 긴몰개(Squalidus gracilis majimae) 그리고 어름치(H. mylodon) 등 19종(61.29%)으로 고유종의 빈도가 매우 높았으며, 천연기념물이 1종, 환경부지정 멸종위기 야생동물 II급 종이 5종으로 각각 확인되었다. 예상되는 종수(기대종)의 분석 결과, 동강의 전 조사지점에서는 18(지점 4, 5)∼22종(지점 3)이 서식하고 있을 것으로 나타났으며, 유사도 분석은 62.28%(지점 1과 2)∼84.13%(지점 1과 5)의 범위로 나타났다. 따라서 동강유역은 어류가 서식하기에 매우 적합한 수환경을 유지하고 있으며, 각 조사지점별 수환경도 매우 유사한 것으로 판단된다. The ichthyofauna and ecological community analysis in the Dong River, Korea, were investigated from May, 2006 to May, 2007. During the surveyed period, 31 species belonging 9 families were collected. Total of 31 species(primary freshwater: 26 species, peripheral freshwater: 5 species) were found with the primary freshwater fishes being highest. Dominant species was Zacco koreanus(55.73%), and subdominant species was Coreoleuciscus splendidus(7.15%). Also, Microphysogobio longidorsalis (6.12%), Hemibarbus mylodon(4.87%), Iksookimia koreensis(4.49%) were numerous. There were 19 Korean endemic species(61.29%), including Acheilognathus signifer, A. yamatsutae, Pseudopungtungia tenuicorpus, C. splendidus, Squalidus gracilis majimae, H. mylodon. Among them, 1 species was identified as qualifying for possible desigantion as a natural monument catergory, and 5 species were identified for designation required to protect under a wildlife category. As result of expected number of species according to rarefaction curve, the expected species of the Dong-river ranged from 19(St. 4, 5) to 22(St. 3) and result of similarity analysis ranged from 62.28%(St. 1 and 2) to 84.13%(St. 1 and 5). In conclusions, we could define that the Dong-river has a very good water conditions as habitat of fish, and habitat conditions also are very similar in every survey sites.

분말 표면 조도의 3차원 레이저 분석기를 이용한 정량화와 압분성형체 강도에 미치는 영향 분석

이동준,윤은유,김하늘,강희수,이언식,김형섭,Lee, Dong-Jun,Yoon, Eun-Yoo,Kim, Ha-Neul,Kang, Hee-Soo,Lee, Eon-Sik,Kim, Hyoung-Seop 한국분말야금학회 2011 한국분말재료학회지 (KPMI) Vol.18 No.5

Green strength is an important property of powders since high green strength guarantees easy and safe handling before sintering. The green strength of a powder compact is related to mainly mechanical and surface characters, governed by interlocking of the particles. In this study, the effect of powder surface roughness on the green strength of iron powders was investigated using a transverse rupture test. Three-dimensional laser profiler was employed for quantitative analyses of the surface roughness. Two different surface conditions, i.e. surface roughness, of powders were compared. The powders having rough surfaces show higher green strength than the round surface powders since higher roughness leads increasing interlocked area between the contacting powders.

고진동레벨에서의 PZ - PT - PMS 계 세라믹의 압전특성

이동준,권순석,신달우,정수현,임기조 ( Dong Jun Lee,Soon Seok Kwon,Dal Woo Shin,Su Hyun Jeong,Kee Joe Lim ) 한국전기전자재료학회 1997 한국전기전자재료학회 추계학술대회논문집 Vol.1997 No.1

도로공사에서 토공장비 최적 이동을 위한 가설도로 위치선정 요소

이동준,김성근,Lee, Dong-Jun,Kim, Sung-Keun 한국건설관리학회 2022 한국건설관리학회 논문집 Vol.23 No.2

Construction industry is facing difficult challenges in terms of productivity, manpower, and industrial accidents. Currently, along with the 4th Industrial Revolution, various high-tech technologies are emerging, and efforts are being made to solve the problem by applying the technologies related to the 4th Industrial Revolution to the construction industry. As part of these efforts, research is being conducted to develop a construction equipment control system to increase productivity and safety at earthworks sites where many and various types of construction equipment are involved, and the system needs a function to increase productivity by optimizing the moving path of construction equipment. In the case of trucks, the location of the temporary road must be optimized in order to optimize the path of movement in the construction site. However, only matters related to the quality standard of temporary roads have been suggested so far, and there is no standardized process for efficiently determining the location of temporary roads. In this paper, the factors and its importance related to the location of the temporary road were identified through field surveys and interviews with experts, and a method for determining the location of the temporary road was presented. It was confirmed that the suggested method through a case study could improve the productivity of earthwork.

기관지확장증의 외과적 치료

이동준,김찬용,Lee, Dong-Jun,Chung, Chan-Yong 대한흉부심장혈관외과학회 1978 Journal of Chest Surgery (J Chest Surg) Vol.11 No.3

Sixty-one bronchiectatic patients were reviewed who were treated by surgical intervention in the Department of Thoracic and Cardiovascular Surgery, Chonnam University Hospital during the recent 14 years from January of 1965 to August of 1978. 1. Various pulmonary resection was performed; lobectomy was 55.5%, lobectomy and segmental resection 20.6%, bilobectomy 13.1%, lobectomy, segmental resection and thoracoplasty 4.9% and pneumonectomy was 3. 2%. 2. The most common associated disease was pulmonary Tbc, its frequency was 47.5% and next was chronic bronchitis [31%]. 3. The postoperative complication was observed in 19.6% [12 cases] and the most common was wound infection. 4. The possibility of recurrence was relatively high in the cases of residual lesion and it needs more intensive medical care. 5. The surgical result was satisfactory in 86.9% (53 cases), slight improvement in 4.9% (3 cases) and the mortality rate was 1.6% (1 case).

주관절주위의 경락(經絡)과 근육(筋肉)의 상관성(相關性)에 관(關)한 고찰(考察)

이동준,오민석,Lee, Dong-Jun,O, Min-Seok 대전대학교 한의학연구소 1997 혜화의학회지 Vol.6 No.1

메타모델을 이용한 플로트오버 설치 작업용 능동형 갑판지지프레임의 근사설계최적화

이동준,송창용,이강수,Lee, Dong Jun,Song, Chang Yong,Lee, Kangsu 한국산업융합학회 2021 한국산업융합학회 논문집 Vol.24 No.1

In this study, approximate design optimization using various meta-models was performed for the structural design of active type deck support frame. The active type deck support frame was newly developed to facilitate both transportation and installation of 20,000 ton class offshore plant topside. Structural analysis was carried out using the finite element method to evaluate the strength performance of the active type deck support frame in its initial design stage. In the structural analysis, the strength performances were evaluated for various design load conditions that were regulated in ship classification organization. The approximate optimum design problem based on meta-model was formulated such that thickness sizing variables of main structure members were determined by achieving the minimum weight of the active type deck support frame subject to the strength performance constraints. The meta-models used in the approximate design optimization were response surface method, Kriging model, and Chebyshev orthogonal polynomials. The results from approximate design optimization were compared to actual non-approximate design optimization. The Chebyshev orthogonal polynomials among the meta-models used in the approximate design optimization represented the most pertinent optimum design results for the structure design of the active type deck support frame.

만성 심낭염의 외과적 요법

이동준,최순호,Lee, Dong-Jun,Choe, Sun-Ho 대한흉부심장혈관외과학회 1978 Journal of Chest Surgery (J Chest Surg) Vol.11 No.3

19 chronic pericarditis patients reviewed who were treated by surgical intervention in the Department of Thoracic and Cardiovascular Surgery, Chonnam University Hospital during the recent 10 years from January of 1968 to January of 1978. 2. There were 14males and 5 females in this series. Range of age varied from 110 days to 61 years. 2. There were two hospital death, one expired 2 days and another 3 days after the pericardiectomy. In both of them, myocardial damage by disease process seemed to be major contributing factor. 2. Clinical and histological study showed tuberculous origin in 8 cases, nonspecific chronic inflammatory changes in 6 cases and pyogenic infection cases in 5 patients. 2. The postoperative complications were observed in 6 cases, and the most common was cardiac arrhythmia and wound infection. 2. The extent of pericardiectomy should be confined to the left and right ventricles to correct the hemodynamic anomaly in general. The results of this procedure has been satisfactory in 89 percent of the cases. 2. Optimal myocardial function in cases of constritive pericarditis was the key to the successful outcome of this procedure.

Immersion gold층의 결함 메카니즘 연구

이동준,최진원,조승현,Lee, Dong-Jun,Choi, Jin-Won,Cho, Seung-Hyun 한국마이크로전자및패키징학회 2008 마이크로전자 및 패키징학회지 Vol.15 No.3

ENIG 층의 결함구조를 이해하고자 immersion gold 층의 결함을 TEM 분석을 이용하여 분석하였다. 세가지 다른 종류의 금도금액을 통하여 immersion gold 층을 얻은 후 습식적으로 TEM 시편을 만들어 이를 비교하였다 이를 통해 immersion gold 도금액의 종류에 의하여 도금막의 결함구조는 크게 영향을 받음을 확인할 수 있었다. 즉, 시안형 치환형 금도금 액을 이용하여 얻은 immersion 금도금 층인 경우에는 결정계면을 따라서 결함들이 집중적으로 존재함을 관찰할 수 있었다. 반면 유기환원제를 도금액에 첨가한 시안형 부분환원형 금도금 액을 이용하여 얻은 immersion금도금 층인 경우에는 grain boundary를 따라 존재하는 공극은 사라졌지만 $5\sim20nm$ 크기의 구형의 공극이 결정계면, 결정내를 상관하지 않고 존재하고 있음을 확인할수 있었다. 이에 비하여 아황산형 치환형 금도금 액을사용하여 얻어진 금도금 층에서는 이러한 결함들이 거의 사라지는 것을 관찰할 수 있었다. Investigation on immersion gold layers was carried out using TEM analysis for the purpose of understanding the defect of immersion gold layer. The immersion gold layers prepared with three different types of baths were observed. The results showed that the defect structure of immersion gold layer is strongly dependent on the types of gold baths. Spherical defects of average 10 nm size were located along the grain boundaries for the specimen formed at KAu$(CN)_2$ bath containing no reducing agent. In the case of the specimen processed at KAu$(CN)_2$ bath containing a reducing agent, the spherical defects of 5-10 nm size were distributed randomly in grains as well as at grain boundaries. However, such defects disappeared almost completely when $Na_{3}Au(SO_3)_2$ bath was used to fabricate an immersion gold.