열경화성 3D 프린트 몰드와 생분해성 소재 접합에 관한 연구

윤성철,마재권,방대욱,최해운,Yoon, Sung Chul,Ma, Jae Kwon,Bang, Dae Wook,Choi, Hae Woon 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.4

Laser heat source was applied on 3D poly urethane model built by 3D printer and cellulous acetate for joining. A diode laser with 808nm wavelength was transmitted through the 3D model and applied on the boundary of ABS/Acetate and 3D poly urethane model. Based on the experimental result, the ABS and 3D built poly-urethane polymers was successfully joined, but the mechanical strength was not enough at the joining boundaries in the range of 6watt to 8watt of laser heat source. However, biodegradable acetate was successfully joined without damaging the 3D built model and mechanical strength was properly achieved. The optimum laser power was found between 5watt and 8watt with scanning speed of 500mm/min, 700mm/min and 1,000mm/min. Based on the SEM analysis the filling mechanism was that the applied pressure on 3D built model squeezed the fluidic thermoplastics, ABS and acetate, into the structure of 3D model. Therefore soundness of joining was strongly depending on the viscosity of thermoplastics in polymers. The developed laser process is expected to increase productivity and minimize the cost for the final products.

오존 감수성 및 저항성 고추 품종의 생리생태 변화

윤성철 한국환경농학회 2004 한국환경농학회지 Vol.23 No.3

공시된 세 품종의 고추에 대한 단기간의 오존 처리로 잎에서 나타나는 전형적인 증상은 갈색의 괴사 반응이었으며, 괴사가 심했던 오존 감수성인 다보탑과 같은 농도에서 괴사가 전혀 없었던 부촌 품종을 오존 저항성 품종으로 판단되었다. 고추의 두 품종에서 오존 처리에 의해 광합성 및 기공 전도도 등의 생리생태적 저해가 뚜렷이 나타났다. 그러나 잎에서 가시피해 정도와 생리생태적 저해 정도와의 상호 연관성으로 고추에서의 오존 저항성 기작을 설명하고자 하였으나 생리생태적 반응으로 잎에서 발생하는 오존 저항성의 기작을 설명할 수 없었다. 다만, 고추에서 오존 처리에 의한 광합성 감소는 뚜렷한 기공전도도 감소와 명반응에서 광합성 기구들의 손상에 기인한다고 여겨진다. 그러나, 암반응에서 생화학적 반응을 설명할 수 있는 A-Ci curve 상에서는 오존 처리에 따른 효과를 찾을 수 없었다. Ozone effects were studied by plant growth chamber to evaluate the impact of ozone (O₃) on the physiology of two hot pepper, Capsicum annuum L., cultivars, 'Dabotab' and 'Buchon'. Forty-day old plants with 5~7 leaves were exposed to O₃ of <20 and 150 nL/L for 8 h/d for 3 days. Net photosynthesis and stomatal conductance were measured and foliar injury was described. Foliar damage due to the treated O₃ was different from the varieties.'Dabotab' was most sensitive to O₃ and 'Buchon' was resistant. Symptom of ozone damage on the leaves was bifacial necrosis. Decreases of net photosynthesis by O₃ were 56% and 40% on 'Dabotab' and 'Buchon', respectively. Decreases of stomatal conductance by O₃ were 66% and 63% on each variety. O₃ damage on net photosynthesis was started at the low levels of light on the two hot peppers. In addition, assimilation-internal CO₂ concentration curves were not different from the two varieties. In conclusion, O₃ closed the stomata and decrease net photosynthesis on hot peppers regardless of the ozone sensitivity on leaf injury, but the difference of ecophysiological responses between the two varieties was not found clearly.

국내 소매은행의 개인신용평가시스템에 대한 연구

윤성철,윤명희,서현석 한국경영과학회 2002 한국경영과학회 학술대회논문집 Vol.2002-A No.-

In an effort to survive from the severe market competition, the Korean retail banks are restructuring their bus messes through Merger & Acquisition, and financial stringency policy As part of the efficient bus mess operation and systematically manage risks, the information systems are introduced and applied to these places.<br/> The current trend of bank for the rising volume in the private loans, the needs for the transparent and scientific loan management, and the regulations from the government, all bring out the importance of the CSS (credit scoring system) these days. The CSS concerns the whole loan processes: the application, examination, analysis, admission, and management, through the computerized system.<br/> The CSS not only systematically manage personal loans efficiently, but also act as a supportive system to reduce risks and increase profits to customers as well as to the banks.<br/> The approach to CSS should not be viewed from the technological standpoint but focused on the evaluation model and strategy oriented management system Therefore, the strategic coupling of the risk management system and the customer relationship management system should be emphasized for the whole process.<br/> Our study conducted literature reviews and the interviews on the persons in charge of the credit scoring system and the private loan of 5 major domestic retail banks to analyze the conditions and the issues in implementation and usage of the credit scoring system and the effect of introduction Based on data from this research, the current study reviews on the credit scoring system of Korean retail banks and suggest its improvement measures.

경제위기에 따른 사망률 불평등의 변화: 지역의 사회경제적 위치 지표의 활용

윤성철,황인아,이무송,이상일,조민우,이민정,강영호,Yun, Sung-Cheol,Hwang, In-A,Lee, Moo-Song,Lee, Sang-Il,Jo, Min-Woo,Lee, Min-Jung,Khang, Young-Ho 대한예방의학회 2005 예방의학회지 Vol.38 No.3

Objectives : An abrupt economic decline may widen the socioeconomic differences in health between the advantaged and disadvantaged in a society. The aim of this study was to examine whether the South Korean economic crisis of 1997-98 affected the socioeconomic inequality from all-causes and from cause-specific mortality between 1995 and 2001. Methods : Population denominators were obtained from the registration population data, with the number of death (numerators) calculated from raw death certificate data. The indicator used to assess the geographic socioeconomic position was the per capita regional tax revenue. Administrative districts (Si-Gun-Gu) were ranked according to this socioeconomic measure, and divided into equal population size quintiles on the basis of this ranking. The sex- and 5-year age-specific numbers of the population and deaths were used to compute the sex- and age-adjusted mortality rates (via direct standardization method), standardized mortality ratios (via indirect standardization methods) and relative indices of inequality (RII) (via Poisson regression). Results : Geographic inequalities from all-causes of mortality, as measured by RII, did not increase as a result of the economic crisis (from 1998-2001). This was true for both sexes and all age groups. However, the cause-specific analyses showed that socioeconomic inequalities in mortalities from external causes were affected by South Korean economic crisis. For males, the RIIs for mortalities from transport accidents and intentional self-harm increased between 1995 and 2001. For females, the RII for mortality from intentional self-harm increased during the same period. Conclusions : The South Korean economic crisis widened the geographic inequality in mortalities from major external causes. This increased inequality requires social discourse and counter policies with respect to the rising health inequalities in the South Korean society.

여러 가지 Perturbing media 에서의 알부민의 비가역적 열변성

윤성철,장광숙 ( Sung Chul Yoon,Kwang Sook Chang ) 생화학분자생물학회 1994 BMB Reports Vol.27 No.5

The thermal denaturation mechanisms of bovine serum albumin (BSA) and its reduced form of cysteinylBSA in PBS buffer (pH 7.0, ionic strength=0.1 or 0.2) were investigated on the basis of kinetic analysis in which in-eversible two-state transition (N→D) was assumed. Several perturbants such as urea, N-methylurea, N,N`-dimethylurea, tetrnmethylurea, acetamide, thiourea, guanidine-HCl, sorbitol and glycerol were employed to perturb the system and to see their effect on the thermal denaturation of BSA and disulfide-broken cysteinyl-BSA. The thermal transition parnmeters, T_m (denaturation peak temperature), ΔH_(cal) (endothermic heat) and C_p (heat capacity) of the two proteins were measured on a Setaram micro-DSC (differential scanning calorimeter) in the presence or absence of those perturbants. The activation energies (E_a) of thermal denaturation of BSA and cysteinyl-BSA were estimated from the analysis of DSC-scan profiles. The estimated activation energies (E_a) ranged from 216 to ∼380 KJ/mol depending on the type and the concentration of the perturbant employed. The activation energy of thermal denaturation of unreduced BSA is higher than that of cysteinyl-BSA, which means that the 17 disulfide bonds contribute to the stabilization of BSA. It was also found that urea, methyl substituted ureas and high-concentration guanidine-HCl destabilized BSA, but the polyhydroxyl perturbants of sorbitol and glycerol stabilized the protein, which was determined from both T_m and E_a data. However, increasing acetamide concentration caused a gradual decrease of T_m and a grndual increase of E_a of BSA Thus, this indicates that the two determinants (T_m and E_a) for thermal stability of proteins are independent of each other. Apparent deviation from the two-state mechanism of BSA thermal denaturation in acetamide-containing PBS buffer was estimated by calculating the van`t Hoff enthalpies (ΔH_(VH)) and comparing them with the calorimetric enthalpies (ΔH_(cal)). An increase of acetamide concentration generally decreased the deviation from the two-state mechanism.

결측값의 대치법

윤성철,Yun, Sung-Cheol 대한예방의학회 2004 예방의학회지 Vol.37 No.3

IT 컨설팅 서비스의 품질 및 사용자 만족도 측정에 관한 연구 - 수정된 SERVQUAL 척도

윤성철,서현석,홍성완 한국경영정보학회 2002 한국경영정보학회 학술대회논문집 Vol.2002 No.-

정보화 계획의 과제 이행에 대한 연구

윤성철,남윤미 한국경영정보학회 2003 한국경영정보학회 학술대회논문집 Vol.2003 No.-

SLA에 기반한 IT 아웃소싱 비용 산정 모형 수립 및 타당성 검토

윤성철,서한준,김민석 대한산업공학회 2003 대한산업공학회 추계학술대회논문집 Vol.2003 No.-

포스터 발표 : 혈액투석 중인 환자에서 High Flux Dialyzer의 혈중 알루미늄 농도에 미치는 영향

윤성철,이은경,조종태 대한신장학회 2006 춘계학술대회 초록집 Vol.25 No.1