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.

가열처리에 의한 단감의 이화학적 특성

손규목,김광호,성태수,김종현,신동주,정지영,배영일 한국식품영양학회 2002 韓國食品營養學會誌 Vol.15 No.2

단감의 기능성 소재 및 기호성이 우수한 부원료로서의 이용 가능성을 확인하기 위하여 단감새옥를 전처리별 즉, 열처리 온도 (25℃, 75℃ 및 95℃) 에서 NaCl (0, 1, 3%) 농도별로 침적 (1, 5분) 하여 동결건조한 시료구를 대상으로 탄닌, 비타민 C, 색도 및 조직감 등을 분석한 결과는 다음과 같다. 탄닌 성분은 열처리 온도, NaCl 농도 및 침적시간이 증가할수록 탄닌함량이 감소하는 경향을 나타내었으며, 특히, 대조구 (420 mg%) 에 비해 95℃에서 1% 및 3% NaCl 농도에 5분간 침적시 각각 228 및 198 mg%로 감소하였다. 비타민 C 함량은 대조구 (122.4 mg%)에 비해 95℃에서 3% NaCl 농도에 5분간 침적시 75.8 mg% 로 감소하였고, 색도는 열처리 온도, NaCl 농도 및 침적시간이 증가할수록 L(명도) 및 b(황색)값이 뚜렷하게 증가한 반면, a(적색도) 값은 감소하였고, ??E 값은 증가하여 처리조건이 가중될수록 색의 변화가 진행됨을 알 수 있었다. 단감껍질과 전처리한 시료 (95℃, 1% NaCl, 5 분)의 flavonol 함량은 껍질에 myricetin(2.0 ㎍/g), quercetin (34. 5 ㎍/g) 및 kaemferol (1.1 ㎍/g) 성분이 검출되었고, 전처리한 시료는 myricetin (9.5 ㎍/g), quercetin (5.5 ㎍/g)이 검출되었다. 조직감은 대조구에 비해 전처리 (95℃, 1% NaCl, 5분) 한 시료에서 부서짐성, 응집성, 점성 및 씹힘성이 우수하였다. 관능검사는 95℃에서 1% NaCl에 5분 및 3% NaCl 농도에 1부간 침지한 시료가 좋은 평가를 받았다. Sweet persimmon were tested in order to identify their use as secondary material which is excellent in function and taste as food. Samples were soaked for 1 and 5 min with NaCl concentration (0, 1 and 3%) at a certain heating temperature (25, 75 and 9r℃), and then tannin, vitamin C, flavonol, color intensity, sensory test and textural properties were analyzed. The results of the analyses were as follows. Tannins were decreased as heating temperature, NaCl concentration and soaking time were increased, especially, that the control was 420 mg% but decreased 228 and 198 mg% at 95℃ (1 and 3% NaCl concentration) for 5 min, soaked in each. Vitamin C content also decreased more in higher temperature and NaCl concentration than control (122.4 mg%). Color intensity showed higher value in L and b than in heating temperature, NaCl concentration and soaked time longer remarkably, but a value decreased. The peel of sweet persimmons was analyzed myricetin (2.0 ㎍/g), quercetin (34.5 ㎍/g) and kaemperaol (1.1 ㎍/g), but in pre-treatment sample ( 95℃, 1% NaCl concentration and 5 min, soaked ) was showed higher myricetin (9.5 ㎍/g) and quercetin (5.5 ㎍/g). Textural properties were good in pre-treatment sample ( 95℃, 1% NaCl concentration and 5 min, soaked) such as brittleness, cohesiveness, gumminess and chewiness. In sensory analysis, the pre-treatment samples (95℃, 1% NaCl concentration and 5 min, soaked and 95℃, 3% NaCl concentration and 1 min, soaked) were showed higher point than others.

다공성 충전층반응기에서 기-액흐름양상의 전이와 액체체류량

손민일,함병호,조지훈,김태옥,장영준 明知大學校 産業技術硏究所 1996 産業技術硏究所論文集 Vol.15 No.-

For both downward and ward cement gas-liquid flow in a porous packed bed reactor the transition of gas-liquid flow pattern and liquid holdup were investigated experimentally in an air-water-Zeolite particle system. Experimental results showed that gas velocity at trickle-to-pulse flow transition boundary in the downflow system was decreased with increasing liquid velocity and that gas velocity at bubble-to-pulse flow transition boundary in the upflow system was nearly constant for lower liquid velocity, however, it was increased with increasing liquid velocity for turbulent flow region. We also found that the dynamic liquid holdup in the upflow system was higher than that in the downflow system and it was increased with increasing liquid velocity and with decreasing gas velocity. Furthermore,the dynamic liquid holdup was sensitively affected by liquid velocity at trickle flow in the downflow system while it was sensitively affected by gas velocity at bubble flow in the upflow system and at pulse flow in the downflow and upflow systems. For the porous particle system fluid velocities at gas-liquid flow transition boundaries and dynamic liquid holdup had nearly same that for the nonporous particle(glass bead) system.

롤의 배열이 자동차용 강판의 두께편차 및 마멸에 미치는 영향

손영지,김순경,전언찬 동아대학교 생산기술연구소 2000 生産技術硏究所硏究論文集 Vol.5 No.1

Work roll wear in the cold rolling of mild steel strip is strongly affected by rolling materials, rolling conditions such as roll arrangement in the cold rolling mill and lubrication. The tests were performed to find the effects of roll arrangement in the cold rolling mill on the work roll wear under the same lubricating conditions. The obtained results are as follows : If the distance of cold rolling is about 60 km, the surface roughness of its was reduced by half(Ra 0.49μm) and Pc(peak count) also was decreased to 60 ea/cm. It is easier for CC(Continuous casting) to make a slip on rolling than IC(Ingot casting). It is due to surface mirror in which first residual product appears and iron powder included Al2O3 is sticked. Because bending degree of 4Hi-rolling mill is higher than 6Hi-rolling mill, the first surface mirror was occurred to its center-point which is loaded strongly. 6Hi-rolling mill shape-controlled by intermediate roll doesn't need the initial crown to work roll. Therefore, fatigue and wear would appear a little bit.

사회과 WBI(Web Based Instruction) 수업 모형 개발 및 적용

손지영 이화여자대학교 교육대학원 2002 이화교육논총 Vol.12 No.-

In the era of information revolution, integrated education is effective on the enhancement of critical thinking and reasonable decision making. However, integrated education has troublesome due to the difficulty of construction and insufficiency of educational skill. In this study, WBI (Web Based Instruction) was applied as a method of integrated education based on the necessity of integrated education in social studies. The usefulness of integrated education using WBI teaching model was investigated. First, the definition, style, and necessity of integrated education was surveyed. And the investigation on the constructivist educational principles and the usefulness of WBI was carried out. The topic of practical class was chosen as the international fight among the strand of Global Connection. Its name was 'Project: World Peace'. The in-class collaborative projects was used as the teaching style based on WBI and then, the integrated education model was developed. For the objective research, the conventional integrated education model was simultaneously developed and the comparison between two models was performed. From the ex post facto questions the analysis on the each question was performed by t-test between two education methods through extraction of common factors using factor analysis and t-test on the each question. The research problems, such as self-directed learning, interactive and collaborative learning-teacher to student, student to student, student to educational materials-, practical useful learning, interest on learning and modification of learning efficiency, were decided. As results of t-test on each question, the mean values in the integrated education based on WBI were higher than those in the conventional integrated education. In addition, the significant difference in most of questions was appeared. In factor analysis, the same results were obtained. The variables on the interaction between student and educational materials, the interest on learning, and the modification of learning efficiency showed the significant difference in statistical significant level (<0.25). However, the variables on the self-directed learning, the collaborative learning-teacher to student, student to student-, and the practical useful learning exceeded the significant level.

STL 포맷의 급속곡면 오류 수정을 위한 시스템 개발

손영지,김순경 동의공업대학 1998 論文集 Vol.24 No.1

This paper recommends database construction for STL data and a new method of Delaunay's triangulation in order to decrease volume errors by verifying STL file errors and modifying hole errors. Each vertex for the boundary coordinates of the verified hole errors was analyzed according to the following cases: planes or slow curves, edges, apexes, and rapid curves, In each case, a different modification process was adopted. With this method, most errors resulting from the conversion into STL data. as well as many volume errors arising from error modification, were decreased.

인후두부 이물감을 호소하는 환자에서의 기질적 요인 및 심인성 요인의 중요성

손영익,권중근,이풍렬,이화영,유범희,김지혜 대한이비인후과학회 1998 대한이비인후과학회지 두경부외과학 Vol.41 No.3

선천성담관낭포의 외과적 처치

손기섭,설지영 충남대학교 의과대학 지역사회의학연구소 1991 충남의대잡지 Vol.18 No.2

Congenital choledochal cyst is relatively rare disease, however, it is common in East Aisan countries especially in Japan, where more than two thirds of cases are reported. Since in 1723, Vater first reported, many authors have been reported over 1500 cases. It has been reported on operative procedures and prognosis in many ways because of complications and associated diseases including pancreatitis, cholangitis, biliary obstruction, calculus formation and carcinogenesis. Congenital choledochal cyst had chiefly been treated by drainage procedures such as cystoduodenostomy, cystojejunostomy and choledochocystoduodenostomy at thebeginning of surgical therapy. Recently, however, cyst excision is preferred because of complications and associated diseases previously mentioned, authors also has been preformed excision and Roux-en-Y hepatico- or choledochojejunostomy for almost all patients of congenital choledochal cysts.

난치성 측두엽 간질환자의 발작간 뇌파소견

김지언,손은익,김준식,이상도,박영춘 대한신경과학회 1998 대한신경과학회지 Vol.16 No.4

상지 단순반복작업 근로자의 수근관 증후군 유병률에 관한 조사

손지언,장태원,김윤규,홍영습,정갑열,김동일,이강진,하남진,김상범,김준연 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.3

목적 : 본 연구는 수근관 증후군의 발생위험이 높은 작업형태에 종사하는 상지 단순반복작업근로자로서 육류 및 어류 가공 사업장과 목재소 근로자에서 근전도검사를 이용하여 수근관 증후군의 유병률을 조사하고자 하였다. 방법 : 상지 단순반복작업근로자로서 육류 및 어류 가공 사업장 근로자 69명과 목재소 근로자 17명을 실험군으로, 관리직, 경리, 경비등 상지의 단순반복작업이 없는 근로자 28명을 대조군으로 선정하여, 작업적 및 병력조사, 이학적 검사와 근전도검사를 통해 수근관 증후군의 유병률을 조사하였다. 결과 : 수근관 증후군의 유병률은 육류 및 어류 가공 사업장과 목재소에서 각각 26.09 % (18명)와 29.41 %(5명)로 조사되었으며, 육류 및 어류가공사업장과 목재소 근로자를 '7년 이상과 미만의 작업기간'으로 층화하여 비교한 결과 '상지부위의 통증 호소 유무', 'Visual Analogue Scale(VAS: 총 10점) 4점 이상 여부', 'Tinel teat 양성 유무', 'Phalen test 양성 유무'는 모두 단기 작업근로자군에서 양성의 빈도가 증가되었고 '수근관 증후군 유무'는 장기작업근로자군에서 양성의 빈도가 증가되었다. 결론 : 육류 및 어류 가공 사업장과 목재소의 수근관 증후군 유병률은 각각 26.09 %와 29.41 %로 육류 및 어류 가공 사업장과 목재소는 1996년 OSHA가 지정한 바와 같이 위험한 작업요인이 있는 작업장으로 분류하여 관리되어야 할 것으로 생각된다. Objectives : This study was carried out to survey on the prevalence of Carpal Tunnel Syndrome(CTS) in high risk jobs(meat and fish processing plant and wood plant), by application of Nerve Conduction Study(NCS), a confirmatory diagnostic method. Methods : Experimental group was 69 workers sampled from meat and fish processing plants and 17 workers sampled from wood plants, who were simple, repetitive workers using upper extremities and control group was 28 workers sampled from managers, secretaries and keepers. All employees were examined through work history, physical examination and NCS. Results : 18 workers(26.09%) in meat and fish processing plants, and 5 workers(29.41%) in wood plants had compatible findings to NIOSH diagnostic criteria for CTS. The experimental group had more symptoms (complaint of upper extremities, Visual Analogue Scale ≥4(VAS: total 10 point)), signs(Tinel and Phalen test) and prevalence of CTS than control group(p<0.05). The prevalence of symptoms and signs were higher in short term workers(<7 years), but the prevalence of CTS was higher in long term workers(≥7 years). Conclusions : The prevalence of CTS in meat and fish processing plant and wood plant were 26.09% and 29.41% respectively. Authors propose that meat and fish processing and wood plants should be managed as a risk job category which were designated by OSHA in 1996