Fe-0.7%C-2.3%Si강의 미세조직과 기계적 성질에 미치는 잔류 오스테나이트 변태 거동

손제영 ( Je Young Son ),권도영 ( Do Young Kwon ),김지훈 ( Ji Hun Kim ),김원배 ( Won Bae Kim ),예병준 ( Byung Joon Ye ) 한국주조공학회 2012 한국주조공학회지 Vol.32 No.3

This steel has been synthesized integrating concepts from Austempering Ductile Cast Iron (ADI) technology. While ADI has excellent mechanical and physical properties, the Young`s modules of ADI is approximately 20% lower than steel. In addition, the presence of graphite nodules in ADI can be sites of crack initiation, where fracture takes place at graphite matrix interface. Because of this limitations of ADI, there has been a growing interest in austempered steels as structural materials in resent years. In this investigation, a new steel with microstructure composed of ferrite and austenite and with simultaneous high tensile strength (1,150MPa) and high ductility (33%) was developed. The goal of this investigation is to obtain a better understanding of deformation and transformation behaviour in high carbon retained austenite(γHC) and over-saturated ferrite(α) during the plastic deformation. A detailed study of the microstructure of this steel was carried out by means of X-ray diffraction (XRD) and electron back scattering diffraction (EBSD) technic. In this way it was shown that BCC phase (BCC) took up the larger part of the nominal strain whereas the a part of retained austenite responded to the mechanincal load by partial martensite transformation, and misorientation change in the retained austenite after plastic strain could be attributed to the large elongation.

노화가 인체 중간엽 줄기세포로부터 조골세포로의 증식 및 분화에 미치는 영향

백기현,태현정,오기원,이원영,조정기,권순용,강무일,차봉연,이광우,손호영,강성구,김춘추 대한내분비학회 2003 Endocrinology and metabolism Vol.18 No.3

연구배경: 일반적으로 골다공증과 연관된 위험인자로는 연령, 폐경, 약물, 불충분한 칼슘섭취, 만성질환 및 운동부족 등이 있는데, 특히 노화가 진행할수록 골밀도가 감소하는 것은 잘 알려져 있다. 노화와 관련하여 진행되는 골소실은 조골세포 및 전구조골세포의 기능적 결핍에 의한 골형성의 감소가 주요한 요인으로 여겨지고 있다. 그 동안 연령이 조골모 세포의 양과 조골모 세포로부터 성숙조골세포로의 분화 및 증식에 미치는 영향에 대한 일부 보고들이 있었으나 아직 일치된 견해는 없는 형편이다. 방법: 다양한 연령의 사람으로부터 골수를 채취, 중간엽 줄기세포가 포함된 단핵세포를 분리한 후 조골세포로 분화하기 좋은 조건하에서 배양하였다. 대상군은다시 젊은군과 노령군으로 구분하여 다양한 변수를 비교 분석하였다. 일차배양에서는 CFU-F를 계수하여 골수내 중간엽 줄기세포의 수를 추산하였고, 칼슘측정을 통하여 기질의 무기화 정도를 비교하였다. 계대배양후 이차배양에서는 시기별로 알카리성 포스파타제 활성도를 측정하고 오스테오칼신 mRNA의 발현을 관찰하여 젊은군과 노령군 사이의 증식능 차이를 비교하였다. 또한 이차배양 시기별로 MTT 측정을 하여 양군간에 증식능 차이가 있는지 알아보았다. 결과: 1. 일차배양 15일째에 평균 CFU-F의 수는 젊은군에서 유의하게 많았다(젊은군 148.3±28.9, 노령군 54.3±9.1, p=0.02). CFU-F의 평균면적은 젊은군에서 넓은 경향을 보였으나 통계적으로 유의하지는 않았다. 2. 일차배양 17일 경과 후 양군간에 기질 칼슘 침착정도는 유의한 차이를 보이지 않았다(젊은군 103.6±50.6, 노령군: 114.0±56.5, p=NS). 3. 이차배양 10일째에 젊은군에서 알카리성 포스파타제 활성도가 고령군에 비해 유의하게 높았다(젊은군: 935.5±115.0 U/mg, 노령군: 578.4±115.7U/mg,p.0.05). 고령군에서는 시간 경과에 따른 변화가 미약했으며 전반적으로 알카리성 포스파타제의 활성도가 젊은군에 비해 낮았다. 4. 이차배양도중 오스테오칼신 mRNA의 발현은 배양시기별로 젊은군에 비해 고령군에서 더 낮은 경향을 관찰할 수 있었다. 5. 이차배양 10일과 15일에 젊은군에서 노령군보다세포증식이 유의하게 증가된 양상을 보였다(10앓 젊은군 0.73±0.05, 노령군 0.58±0.04, p=0.05, 15일; 젊은군 0.80±0.05, 노령군 0.70±0.03, p=0.05).결론: 이상의 연구에서 저자들은 노령군에서 젊은군보다 골수 내 중간엽줄기세포의 수가 적고, 노령군에서 유래한 전구조골세포의 성숙조골세포로의 증식 및 분화가 젊은군 보다 감소해 있는 것을 관찰할 수 있었다. Background: Osteoblasts originate from osteoprogenitor cells in bone marrow stroma, termed mesenchymal stem cells (MSCs) or bone marrow stromal cells. Each MSC forms colonies (colony forming units-fibroblasts [CFL-Fs]) when cultured ex vivo. There are some reports about the age-related changes of the number and osteogenic potential of osteoprogenitor cells, but any relationship has not been clearly established in humans. In this study, we counted MSCs using CFU-Fs count and examined the proliferative capacity and differentiation potential of osteoprogenitor cells. Finally, we analyzed how these parameters varied with donor age. Methods: Bone marrow was obtained from the iliac crest of young (n=6, 27.2±8.6 years old) and old (n= 10, 57.4k6.7 years old) healthy donors. Mononuclear cells, including MSCs, were isolated and cultured in osteogenic medium. In primary culture, we compared the colony-forming efficiency of MSCs between the two groups and determined the matrix calcification. When primary culture showed near confluence, the cells were subcultured. Alkaline phosphatase activity, osteocalcin expression by RT-PCR and proliferative potential by MTT assay were examined by the time course of secondary culture. Results: At the 15th day of primary culture, the mean number of CFU-Fs was significantly higher in the younger donors (young: 148.3±28.9, old: 54.3±9.1, p=0.02) and the mean size of CFL-Fs was also larger in the younger donors than the older donors. However, matrix calcification was not different between the two groups (young: 103.6±50.6, old: 114.0±56.5, p=NS). In secondary culture, alkaline phosphatase activities were significantly lower in the older donors. The younger donors showed peak alkaline phosphatase activity at day 10, while the older donors didn't showed a remarkable peak (young: 935.5±115.OU/mg, old: 578.4±115.7U/mg, p<0.05). Total cell number as a proliferative index increased progressively during the secondary culture and a significantly greater cell number was noted in the younger donors. Osteocalcin expression was generally upregulated in the younger donors, but this was not statistically significant. Conclusion: Our study shows that the number of osteoprogenitor cells is decreased during aging and that the proliferative capacity and differentiation potential of osteoprogenitor cells seem to be reduced during aging (J Kor SOC Endocrinol 18:296-305, 2003).

활막육종

김재도,윤영민,손정환,홍영기,손영찬,박정호,Kim, Jae-Do,Yoon, Young-Min,Son, Jeong-Whan,Hong, Young-Gi,Son, Young-Chan,Park, Jeong-Ho 대한근골격종양학회 1996 대한골관절종양학회지 Vol.2 No.1

Synovial sarcoma is an uncommon malignant soft tissue tumor which usually occurs in young-aged person, and frequently involves the lower extremities. Many authors recommended wide excision, adjuvant chemotherapy and radiation therapy. The proposed factors that affect the prognosis are age, size of tumor, site of tumor in the body, depth of tumor, histologic grade and method of treatment. The purpose of the study is to analyze the factors that affect the 5-year survival rate. We retrospectively evaluated 19 cases of synovial sarcoma treated in the Kosin University Medical Center from Jan. 1982 to Dec. 1994. The overall 5-year survival rate was 47.6% and the 5-year survival rates were significantly higher(P<0.05) in the group with smaller size of mass. The significantly lower 5-year survival rates were observed in the patient with deeply located lesion and with higher histologic grade. The 5-year survival rates were higher in the patients treated with wide excision than in the patients treated with amputation. But there was no significant difference between these groups. The adjuvant chemotherapy and radiotherapy were performed. In conclusion, we suggest that the better prognosis will be observed in the patients with smaller size of tumor mass, superficially located and lower histologic grade.

Classification using the Bezier Curve

Son,Young Nam,Cho,Byung Yup,Yang,Jong Hyun 한국자료분석학회 1999 Journal of the Korean Data Analysis Society Vol.1 No.2

Recently, nonparametric methods of curve estimation have become useful technique in applied statistics. Among the methods, nonparametric regression using various splines have been focused due to its flexibility. However, it is little known about the properties of Bezier spline for nonparametric regression. In this paper, we develop a classifier in classification problem by nonparametric regression using cubic Bezier curve. Various classification methods are compared with the proposed method. The newly developed method which will be called classification using Bezier(CUB) seems to be comparable to existing methods like CART, CUS or neural network classifier in terms of misclassification error rates.

The Effect of the Preference for Housing Wealth on Consumption

Young Seob Son1 사람과세계경영학회 2011 Global Business and Finance Review Vol.16 No.2

This article offers a theoretical model on the preference for housing wealth under uncertainty to prove that the marginal propensity to consume (MPC) out of housing wealth may be smaller than that of financial wealth. We found that the preference for housing wealth induces a smaller MPC out of housing wealth, but the effects of the volatility and the expected growth rate of housing wealth on the MPC are stronger than those of financial wealth. Another interesting result is that it is possible for the preference for housing wealth to increase both MPCs.

The Jeju 4·3 Incident and the Existence of Haenyeo in Lisa See’s The Island of Sea Women

Young-Hee Son 한국언어과학회 2020 한국언어과학회 학술대회 Vol.2020 No.10

The Island of Sea Women (2019) by Lisa See, an American best-selling author, is an epic that vividly portrays the violence and wounds of Jeju 4·3 incident and the friendship and betrayal of two protagonists, Young-sook and Mi-ja who are female divers called haenyeo in Jeju province. The life of Jeju haenyeos depicted in the work is so indigenous that it is surprising that this work was written by a foreign author. This paper aims to analyze national violence, wounds and trauma and explore the possibility of reconciliation and coexistence focusing on Jeju 4·3 incident and Jeju haenyeo, which are the central themes of The Island of Sea Women. First, I would like to borrow the concepts of Giorgio Agamben, who argued that individuals can be reduced to bare life within the state of exception created by sovereign power like the example of the concentration camps of World War Ⅱ, to analyze the national violence in The Island of Sea Women. Second, this paper will draw on eco-feminism theory to explore the haenyeo’s lifestyle. Eco-feminism pursues diversity and a harmonious symbiosis between humans and nature. This is in line with the harmony and coexistence of Jeju haenyeos and their sense of community. The purpose of this paper is to understand the historical truth and scars and provide a new foundation for looking at our history through the well-known but unfamiliar story of Jeju in See's The Island of Sea Women and also cast light on the message of hope, overcoming, understanding and forgiveness Lisa See has focused on in her novel.

CONTROLLABILITY OF THE NONLINEAR NEUTRAL FUZZY INTEGRO-DIFFERENTIAL EQUATION ON E^(n)_(N)

Kwun, Young-Chel,Son, Ki-Do 동아대학교 부설 기초과학연구소 2004 基礎科學硏究論文集 Vol.21 No.1

In this paper we study the controllability for the nonlinear neutral fuzzy integro-differential equations on E^(n)_(N) by using the concept of fuzzy number of dimension whose values are normal, convex, upper semicontinuous and compactly supported surface in R^(n). E^(n)_(N) be the set of all fuzzy numbers in R^(n) with edges having bases parallel to axis X_(1), X(2),‥,X_(n).

미세 전기기계 시스템용 알루미늄 박막의 탄성계수 및 항복강도 평가

주영창,손동일,관동일 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.3

Nowadays, the aluminum films have wide application in micromechanical devices such as micro sensors and actuators, so that their mechanical properties come to be very important for reliability evaluation. However, there is no standardized method to evaluate the mechanical properties of material used in MEMS (micraelectromechanical system) device since the measured mechanical properties are influenced by many factors such as surface condition, friction force, etc. Hence, we intended to evaluate the mechanical properties of thin film in our study, which is important in mechanical operation. Because MEMS devices are usually operating in elastic range, the Young's modules and yield strength were evaluated by using microcantilever beam technique. First, Al cantilever beams were fabricated using the silicon bulk micromachining technology to have various film thickness. And then, the load-displacement curve was obtained by nanoindentation method. The linear relation in elastic range was utilized in deriving the Young's modulus of Al film, which gives us reproducible result regardless of film thickness. In high load range, the deviation from the linear relation was detected, so that the yield strength of Al film could be evaluated. It is found that the yield strength increases with decreasing film thickness. By applying the misfit dislocation theory and the Hall-Petch relation, the theoretical estimation could predict well the trend of yield strength.

암처리 엽수와 기간이 들깨의 생육 및 개화에 미치는 영향

최영훈,최영환,이영근,김용균,손병구,강점순,김근기 밀양대학교 농업기술개발연구소 2000 農業技術開發硏究所報 Vol.4 No.1

The lower leaves shading in upper leaves is unknown to be reduced significantly due to the early differentiation of flower-bud by dark treatment of leaves when growing perilla for harvesting the leaves in the greenhouse during the winter. This study analyzed the effect of dark treatment of leaves on the growth and regulation of flowering, which are closely related with differentiation of flower and amount of leaves. One leaf and 3 leaves per plant were dark treated for 0, 5, 10 days. Plant hight was reduced in 3 leaves treatment, but there was no difference in 1 leaf treatment. Stem diameter was reduced in both 1 leaf and 3 leaves treatments, which was more significant in 3 leaves treatment. Leaf area was reduced when 1 leaf was treated for 10 days, but there was no difference when 1 leaf was treated for 5 days. When 3 leaves were treated, leaf area was no difference between treatments. However, leaf area which 3 leaves were treated was reduced more significantly than that 1 leaf was treated. Seed weight was remarkably decreased when 1 leaf was treated for 10 days, and it was decreased when 3 leaves were treated for more than 5 days.

기내배양시 GA₃처리에 의한 들깨의 생육 및 개화조절

최영환,최영훈,강점순,손병구,이영근,주우홍 밀양대학교 농업기술개발연구소 2000 農業技術開發硏究所報 Vol.4 No.1

This study was conducted to estimate growth of leaf and shoot and flowering as affected by GA3 treatment in vitro. Plant height was longer as the concentration of GA3 was higher up to 2.0mg/l. Stem diameter was thick up to the concentration of GA3 was 0.1mg/l , but become thinner as the concentration of GA3 was higher. Root weight and root length were well developed in GA3 concentration was 0.5∼2.0mg/l. Number of roots was more in GA3 concentration was 0.5 and 1.0mg/l . The first flowering occurred in 40 days after 0.5 mg/l GA3 treatment. As the concentration of GA3 was higher, flowering was delayed. Number of flowering was significantly increased in GA3 concentration was 0.1 and 0.5mg/l. However, it was gradually decreased after 60 days. Percentage of flowering per plant was highest in GA3 concentration was 0.5mg/l , but it was lower as the concentration of GA3 was increased.