선박 해수배관에서 용접봉의 종류에 따라 직류 아크 용접한 용접부위의 부식특성에 관한 전기화학적 평가

이성열(Sung-Yul Lee),이규환(Kyu-Hwan Lee),원창욱(Chang-uk Won),나승수(Shane Na),윤영곤(Young-Gon Yoon),김윤해(Yun-Hae Kim),이명훈(Myeong-Hoon Lee),문경만(Kyung-Man Moon),김진경(Jin-Gyeong Kim) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.3

The seawater pipes in the engine rooms of ships are surrounded by severely corrosive environments caused by fast flowing seawater containing chloride ions, high conductivity, etc. Therefore, it has been reported that seawater leakage often occurs at a seawater pipe because of local corrosion. In addition, the leakage area is usually welded using shielded metal arc welding with various electrodes. In this study, when seawater pipes were welded with four types of electrodes(E4311, E4301, E4313, and E4316), the difference between the corrosion resistance values in their welding zones was investigated using an electrochemical method. Although the corrosion potential of a weld metal zone welded with the E4316 electrode showed the lowest value compared to the other electrodes, its corrosion resistance exhibited the best value compared to the other electrodes. In addition, a heat affected zone welded with the E4316 electrode also appeared to have the best corrosion resistance among the electrodes. Furthermore, the corrosion resistance of the weld metal zone and heat affected zone exhibited relatively better properties than that of the base metal zone in all of the cases welded with the four types of electrodes. Furthermore, the hardness values of all the weld metal zones were higher than the base metal zone.

강널말뚝 합성형 공법에 관한 연구 및 개발

이성열(Lee Sung Yul),유종영(Yu Jong Young) 대한토목학회 2006 대한토목학회 학술대회 Vol.2006 No.10

개량형 C95600 청동의 기계적 성질과 미세조직에 미치는 퀜칭 열처리의 영향

이성열(Sung-Yul Lee),문경만(Kyung-Man Moon),오재환(Jae-Hwan Oh),신동일(Dong-Il Shin) 한국해양공학회 2011 韓國海洋工學會誌 Vol.25 No.6

Modified C95600 bronze contains Fe component if 0.7 weight percentage besides Cu-7Al-2.5Si composition. The shape of centrifugal cast is a circular pipe with thick wall. Specimens machined from the centrifugal cast were quenched in oil after isothermal holding at a given heat treatment temperature in the range of 700-900 ℃. Mechanical properties and structural morphology are depended on the quenching heat treatment temperature regardless of isothermal holding time. Tensile strength or Brinell hardness is increased with increasing heat treatment temperature. The microstructure caused by quenching contains mixing phases of α+β’+ FeSi+κ, which martensite if β’ phase has been transformed from β phase. Effect of isothermal holding temperature on mechanical properties in case of quenching heat treatment attributes to the change if volume fraction if β" on the structural morphology. Mechanical characteristics of specimen, initially quenched fram 850 ℃, and then tempered at 500 ℃, does not show an obvious softerning indication, because disappearance of β’ during tempering process can be compensated by precipitation of brittle phase ?.

피스톤 크라운용 단강에 인코넬 718 용접재료로 용접된 용접부의 특성 평가

이성열(Sung-Yul Lee),문경만(Kyung-Man Moon),정재현(Jae-Hyun Jeong),이명훈(Myeong-Hoon Lee),백태실(Tae-Sil Baek) 한국해양공학회 2016 韓國海洋工學會誌 Vol.30 No.4

The combustion chamber of a diesel engine is often exposed to a more serious wear and corrosion environment than other parts of the engine because its temperature increases as a result of using heavy oil of low quality. Therefore, repair and built-up welding methods must be performed on worn or corroded parts of the piston crown, exhaust valve, etc. from an economical point of view. In this study, Inconel 718 filler metal was used in repair welding on the groove of a forged steel specimen for a piston crown, along with built-up welding on the surface of another forged steel specimen. Then, the corrosion characteristics of the weld metal zone for the repair welding and the deposited metal zone for the built-up welding were investigated using electrochemical methods in a 35% H2SO4 solution. The deposited metal zone indicated better corrosion resistance than the weld metal zone, showing a nobler corrosion potential, higher impedance, and smaller corrosion current density. It is considered that metal elements with good corrosion resistance were generally included in the filler metal, and these elements were also greatly involved in the deposited meta by built-up welding, whereas the weld metal consisted of metal elements mixed with both the filler metal and base metal elements because of the molten pool produced by the repair welding. Finally, it is considered that the hardness of the weld metal was increased by the repair welding, whereas the built-up welding improved the corrosion resistance of the deposited metal.

멜라닌세포성 피부병변에서 AgNORs의 단순 계수법과 컴퓨터 영상분석법의 비교연구

이성열(Sung Yul Lee),오칠환(Chil Hwan Oh) 대한피부과학회 1993 大韓皮膚科學會誌 Vol.31 No.6

Background : Nucleolar organizer regions(NORs) are loops of DNA that transcribe ribosomal RNA; they can be easily identified in paraffin section using silver method. Recently, the application of NORs to the study of various types of benign and malignant proliferation has suggested that the number of NORs per nucleus can provide an indication of degree of cellur maligriancy. Many authors indicated a significant overlapping of NORs counts between benign and malignant proliferation. Objective : The purpose of this study is to discriminate benign m laocytic nevi from malignant melanoma effectively, thus we use simple enumeration and computerized image analysis of AgNORs in melanocytic skin lesions. Method : NORs were investigated on silver stained histologicec ion of 18 malignant melanoma (MM), 19 acquired nevi(AN), 21 congenital nevi(CN). For each case, 100 nucleus sample were cuantified using image analysis system(AIC Inc., Roswell, GA). There is no consensus at present as to the best criterion for quantifying AgNORs proteins in melanocytic skin lesion. We prefer to quantify a large number of parameters. The mean value or standard deviation(SD), each calculated for a batch of 100 cells, are average again(mean+SD), over the 58 cases for six morphological criteria mean number of AgNORs per nucleu, mean ratio of AgNORs area per ruc eus area, mean area of largest AgNORs, mean ratio of largest AgNORs area per nucleus area, mean nucleus area per a AgNOR, and coefficient of variation of nucleus area. Results : 1. All of the six parameters show significant difference between benign melanocytic nevi and malignant melanoma. But., there is no significant difference between acquired nevi and congenital nevi. 2. In stepwise discriminate analysis, we discriminate benign melanoctic nevi from malignant melanoma effectively using combined two parameters(number of AgNORs and mean ratio of AgNORs area per nucleus area). But there is some overlapping between malignant melanoma and ber ign melanocytic nevi using each six parameters. 3. In metastatic and non-metastatic malignant melanoma, six param ters have not shown significant difference. Conclusion : Study of AgNORs in the image analysis system is a very useful tool to differentiate malignant melanoma from benign melanocytic nevi. (Kor J Dermatol) 1993;31(6):866-876)

Permanent makeup removal from murine skin using a 1,064 nm Q-switched Nd:YAG laser: comparison of the degree of removal when irradiated at various time points after application

이성열 ( Sung Yul Lee ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.2

Backgroud: Various Q-switched(QS) lasers, such as ruby, alexandrite or neodymium:YAG(Nd:YAG) lasers, are used to remove tattoos and permanent makeup. To our knowledge, there has been no indication or guideline published for the optimal time for laser-mediated tattoo removal. Objective: To set a guideline for the optimal irradiation time for tattoo and permanent makeup removal via 1,064nm QS Nd:YAG(QSND) laser, we compared the degree of tattoo removal and skin histologic changes when the irradiation was employed at different time points. Mothods: Rat skin was marked with 54 artificial permanent makeup marks with black ink using a permanent makeup machine. The marks were irradiated with a 1,064 nm QSND laser on the application day, and 3 days, 5 days, 1 week, 2 week, and 3 weeks after application. Pigmentation changes were checked over time using a Mexameter and skin biopsy. Results: There was no significant difference in the degree of pigment removal as examined by Mexameter on the day of makeup application compared to 3 days, 5 days, 1 week, 2 weeks, and 3 weeks after application. Histologically, the permanent makeup pigments seemed to move from epidermis to superficial and mid dermis with time. The pigments were relatively well removed throughout the epidermis and dermis when the laser was employed 7 days after tattoo application, compared to laser irradiation on the day of application, as viewed histologically. Conclusion: Laser removal of permanent makeup is effective on the day of application, as determined by testing pigment levels. However, based on histopathology, it is recommended to use lasers to remove permanent makeup about a week after application, since the wound repair process is almost complete at that time.

복싱 잽(jab) 동작 시 상지회전 운동이 근활성도에 미치는 영향

이성열 ( Lee Sung-yul ),권문석 ( Kwon Moon-seok ),조효구 ( Cho Hyo-gu ),김진표 ( Kim Jin-pyo ) 대한무도학회 2017 대한무도학회지 Vol.19 No.2

본 연구는 복싱 잽(jab) 동작 시 상지회전 운동에 따른 근활성도를 분석하는데 목적이 있었다. 최근 1년간 근골격계 상해을 경험하지 않은 대학교 남자 복싱선수 7명이(나이: 21.44±0.53 yrs, 신장: 171.22±4.32 cm 체중: 66.00±8.43 kg, 경력 7.22±0.67 yrs) 3가지 Type으로(Type 1: 손등이 위쪽, Type2: 손등이 좌측방향, Type 3: 손등이 우측방향) 잽 동작을 수행하는데 발생되는 상지 근육들의 활성도를 측정하였다. Noraxon wireless system을 이용하여 인체 근육의 활성도 자료를 수집하였으며 상지회전 운동에 따른 잽의 3가지 Type에 따른 차이를 검증하기 위해 one-way repeated ANOVA(α=.05)에서 실시하여 다음과 같은 결과를 도출하였다. 복싱 잽 동작 시 상지 근육들의 근활성도 및 최대 손 속도 그리고 Type 1에 대하여 일반화한 수치를 분석한 결과, Type 3 조건에서 통계적으로 가장 큰 수치를 나타내었다. 그러므로 복싱 잽 동작 시 상지의 회내 회전 운동은 펀치력을 상승시킬 수 있을 것으로 사료된다. The purpose of this study was to analyze the effect of upper extremity rotation movement on muscles activation of upper and forearm during the boxing jab. Eight elite boxing player(age = 21.44±0.53 yrs, mass = 66.00±8.43 kg, height = 171.22±4.32 cm, career = 7.22±0.67 yrs) were performed three type of jab(Type 1: the back of the hand toward ground, Type 2: the back of the hand toward right, Type 3: the back of the hand toward left) on muscles activation of upper and forearm. All muscles activation data was collected using Noraxon wireless system. The value of mean IEMG, %RVC and velocity of hand were compared among the three type of jab by using the one way repeated ANOVA(a=.05). The results indicated that mean IEMG, velocity of hand and normalized value by Type 1 were significantly higher in the Type 3 condition. Therefore, it was known that upper extremity internal rotation may increase power of punch for attacking game during a boxing jab.

ab initio Calculations on Alkali Atom - Rare Gas Van Der Waals Clusters

이보순,이성열,Lee, Bo Soon,Lee, Sung Yul Korean Chemical Society 2000 대한화학회지 Vol.44 No.3

M-Rg 및 M-Rg2 (M=Li,Na,Rg=He,Ar) 반데르발스 복합체들에 대한양자화학적계산을 시행하였다. AIl-electron MP2(6-311++G(3df,3pd))에 의하여 계산된 LiHe, LiAr 및 NaAr의 균형 핵간 거리와 결합 에너지는 실험값과 잘 일치하였다. $LiHe_2,\;LiAr_2$ 및 $NaAr_2$에 대하여 계산된 분광학적 성질들도 또한 계산하였다. ab initio calculations are presented for M-Rg and M-Rg2 (M=Li, Na, Rg=He, Ar) van der Waals clusters.InternucIear distances and binding energies of LiHe, LiAr and NaAr obtained by all-electron MP2(6-311++G(3df,3pd)) method are in good agreement with experimental values. Calculated properties of LiHe$_2$, LiAr$_2$, NaHe$_2$ and NaAr$_2$ are also reported.

충청남도 지역에서 진단된 표피낭종에 대한 임상 및 병리조직학적 고찰

김성근 ( Sung Keun Kim ),권혁 ( Hyuk Kwon ),이성열 ( Sung Yul Lee ),이종석 ( Jong Suk Lee ),황규왕 ( Kyu Uang Whang ),박영립 ( Young Lip Park ),김준혁 ( Jun Hyuk Kim ),조현득 ( Hyun Deuk Cho ) 대한피부과학회 2009 大韓皮膚科學會誌 Vol.47 No.5

Background: Epidermal cysts are the most common type of epithelial cysts of the skin. There have been a few studies to determine the clinical and histopathological characteristics of epidermal cysts. Objective: The purpose of this study was to evaluate the clinicopathological characteristics of 243 cases of epidermal cysts in the province of Chungcheongnam-do. Methods: We retrospectively evaluated the clinical and histopathological features of 243 cases of epidermal cysts at Soonchunhyang University Hospital in Cheonan from January 1998 to December 2008. Results: The ratio of male to female patients was 1.7:1. The age distribution of subjects at the first visit ranged from 11 months to 83 years. The most common site of occurrence was the face. The most common histopathological change of the cystic wall was atrophy. Cystic contents such as calcifications, parakeratotic cells, red blood cells as well as keratinous material were observed. We found stromal changes such as foreign body reactions, fibrosis and granulation tissue. Forty-seven cases were clinically misdiagnosed as other diseases, but subsequent histopathological findings demonstrated the presence of epidermal cysts. No particular relationship was found among duration, size, atrophy of the cyst wall and calcification of keratin material. Conclusion: We reaffirmed contiguity with previous reports. In addition, we found some cases could have been clinically misdiagnosed as other diseases. In addition, there was a poor relationship between the duration of the lesion and other variables such as the size of the lesion, the degree of atrophy of the cyst wall and calcification of keratin material. (Korean J Dermatol 2009;47(5):516~523)

오스템퍼링 처리한 회주철의 파괴특성에 미치는 오스템퍼링 온도의 영향에 관한 연구

김창규,이성열,최창옥 ( Chang Gyu Kim,Sung Yul Lee,Chang Ock Choi ) 한국주조공학회 1992 한국주조공학회지 Vol.12 No.6

N/A Grey cast iron containing a small amount of Cu and Mo to improve the effect of heat treatment and microstructure were cast and them austenitized. After austenitizing the specimens of castings were austempered at 250℃, 300℃ and 350℃. The effects of matrix structures on mechanical properties and fracture characteristics at the different austempering temperature were investigated. Tensile strength, hardness and impact toughness of austempered grey cast iron showed maximum valve 359㎫, 321 HB, 3.9 CVN respectively at the lowest austempering temperature, 250℃. K_(IC) of gref cast iron at a austempering temperature, 250℃, showed maximum 44㎫.m^(½) even though the amount of retained austenite in it is only 16%. This mainly comes from the refinement of the retained austenite. Quasi-cleavage pattern with a little fit of fibrous pattern was shown on the fractured surface of austempered grey cast iron at all of the temperatures tested.