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.

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.

혁신저항, 만족 및 도입 성과에 대한 연구: 로보틱 프로세스 자동화 사례

윤성철,노종극,이정우,Yoon, Sungchul,Roh, Jonggeuk,Lee, Jungwoo 한국디지털정책학회 2021 디지털융복합연구 Vol.19 No.7

많은 조직들은 직원들의 반복적이고 규칙적인 작업들의 자동화로 업무의 정확도와 효율성을 개선하기 위해 로보틱프로세스자동화(RPA)를 도입하고 있다. 일부 직원들은 귀찮고 무의미한 업무를 피하기 위해 RPA 도입에 적극적으로 참여하지만, 일부는 실직을 두려워하여 혁신에 저항하는 모습을 나타내고 있다. 본 연구는 RPA 도입시 긍정적, 부정적 선행 요인들이 조직 성과에 영향을 미치는 것으로 상정되었다. 상대적 이점, 적합성, 변화관리효과, 혁신저항, 만족도가 최종적으로 도입 성과에 미치는 효과를 한 제조사의 11개 RPA 프로젝트에 참여한 109명 직원 대상 설문과 구조 방정식 모형 분석을 통해 검증하였다. 개인별 구체적인 변화관리 전략을 위해, 혁신저항 모형의 소비자 특성을 고려한 연구가 후속으로 진행될 수 있을 것이다. Many organizations are applying robotic process automation (RPA) to automate repetitive and rule based tasks to enhance the accuracy and efficiency of works. Some members are willing to join the projects hoping to eliminate annoying and meaningless tasks, but others are resisting this innovation fearing that they may lose their jobs. In this study, both positive and negative antecedents are posited to influence the performance in adopting RPA. The effects of relative advantage, compatibility, change management effect, innovation resistance and satisfaction, conclusively to performance improvement were examined via a survey of 109 employees involved in the 11 RPA projects in a manufacturing company, and the structural equation model analysis. The research considering the consumer characteristics of the innovation resistance model can be followed for the development of individualized change management strategy.

여러 가지 Perturbing Media에서의 알부민의 비가역적 열변성

윤성철,장광숙,Yoon, Sung-Chul,Chang, Kwang-Sook 생화학분자생물학회 1994 한국생화학회지 Vol.27 No.5

Two-state model을 바탕으로 하여 혈장 알부민(bovine serum albumin)과 그 disulfide 결합이 끊어진 cysteinyl-알부민의 비가역적 열변성 기작을 조사하였다. 고감도 시차주사 열량계(differential scanning calorimeter, DSC)로부터 얻은 알부민의 DSC scan profiles을 속도론적으로 분석하므로써 열변성 활성화에너지($E{\alpha}$)를 구하였다. Urea, N-methylurea, N,N'-dimethylurea, tetramethylurea, acetamide, thiourea, guanidine-HCl, sorbitol, glycerol 등과 같은 perturbants가 알부민의 변성에 어떤 영향을 주는지를 조사하였다. Perturbant의 종류 및 농도에 따라 $E{\alpha}$가 216~380 kJ/mol의 범위값을 나타냈다. 비환원 알부민의 $E{\alpha}$가 cysteinyl-알부민보다 높게 나타났다. 이는 17개의 disulfide 결함이 알부민의 안정화에 기여함을 의미한다. 이용된 perturbants는 네가지 type으로 분류되었다. 첫째, sorbitol, glycerol, 등은 농도를 증가시킴에 따라 알부민의 $E{\alpha}$와 $T_m$(endothermic peak temperature) 모두를 증가시킴으로써 강력한 안정화제임을 나타냈다. 둘째, urea, 메틸치환 urea, thiourea 등은 농도가 증가함에 따라 알부민 변성 활성화에너지($E{\alpha}$)와 $T_m$의 감소를 보임으로써 강력한 변성제임을 나타냈다. 셋째, acetamide는 농도가 증가함에 따라 $E{\alpha}$의 증가, $T_m$의 감소의 양면성을 보여주었다. 특히, acetamide의 경우 농도가 7~8M일 때 알부민의 열변성은 정확한 two-state 전이과정을 거치는 것으로 확인되었다. 넷째, guanidine-HCl은 ~1M 이하 농도에서는 안정화 효과를 보이다가 그 이상 농도에서는 변성제로 작용하는 현상을 보였다. The thermal denaturation mechanisms of bovine serum albumin (BSA) and its reduced form of cysteinyl-BSA in PBS buffer (pH 7.0, ionic strength = 0.1 or 0.2) were investigated on the basis of kinetic analysis in which irreversible two-state transition ($N{\rightarrow}D$) was assumed. Several perturbants such as urea, N-methylurea, N,N'-dimethylurea, tetramethylurea, 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 parameters, $T_m$ (denaturation peak temperature), ${\Delta}H_{cal}$ (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 ($E{\alpha}$) of thermal denaturation of BSA and cysteinyl-BSA were estimated from the analysis of DSC-scan profiles. The estimated activation energies ($E{\alpha}$) ranged from 216 to ~380 KJ/mol depending on the type and the concentration of the perturb ant 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 $E{\alpha}$ data. However, increasing acetamide concentration caused a gradual decrease of $T_m$ and a gradual increase of $E{\alpha}$ of BSA. Thus, this indicates that the two determinants ($T_m$ and $E{\alpha}$) 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 (${\Delta}H_{VH}$) and comparing them with the calorimetric enthalpies (${\Delta}H_{cal}$). An increase of acetamide concentration generally decreased the deviation from the two-state mechanism.

표면 요철 처리 된 광경화성수지의 레이저 접합 특성

윤성철,최해운,Yoon, Sung Chul,Choi, Hae-Woon 한국레이저가공학회 2015 한국레이저가공학회지 Vol.18 No.4

Specially designed and 3D printed samples were prepared and joined by a diode laser source. To increase the strength of joining and reliability of samples, the surface was patterned by using a 3D printer. The joining surface was prepared as hemispherical shape with no-patterns, 0.5mm pitch, 0.75mm pitch and 1mm pitch. The optical properties of samples were measured by using an integrated sphere where classical Kubelka-Munk theory and modified Richard-Mudgetts theory for the analysis applied. Scanning speed was set at 500mm/min and laser power was varied between 9 and 10watts for the preliminary joining characteristic analysis.

안경테제조를 위한 친환경 아세테이트 수지의 레이저 접합특성에 관한 연구

윤성철,박승규,박중언,최해운,Yoon, Sung Chul,Park, Sung Gyu,Park, Joong Un,Choi, Hae Woon 한국레이저가공학회 2014 한국레이저가공학회지 Vol.17 No.4

Laser beam was applied on the boundary of the polyurethane and biodegradable polyacetate polymers. The distributed laser passed through the polyurethane layer and heated the polyacetate layer, then the soften acetate was squeezed thorough the 1mm square slots of polyurethane for the mechanical joining. The surface roughness ranging between $0.28{\mu}m$ and $3.06{\mu}m$ had almost no effect on joining strength, but the optical properties of HD (High Definition) and UHD (Ultra High Definition) mode affected laser beam transmittance. The optimum laser power was found to be between 8watt and 10watt with 500mm/min of scanning speed. The joining boundary was characterized by optical and SEM analysis. Based on the experiment and characterization results, the laser energy was effective for the polymer joining and efficiency of joining.

고무재를 사용한 판재의 차량하중에 의한 구조해석

윤성철(S. C. Yoon) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월

As the public use part of the railway and the road, the railway crossing is important to work properly by two transportation means. Also, It is important to provide the good face of friction on the railway crossing in aspect of protecting the railway crossing accident. Lately, Many kinds of the material are used for railway crossing panel. As they have a various fault, it was studied to analyze the structural action of the new material, rubber panel. This paper analyzed stress and displacement by truck passing weight using the Finite Element Modeling.

독일에서의 시위범죄에 대한 형사법적 관점의 논의

윤성철 ( Seong Cheol Yoon ) 이실학회(구 한국경찰이론과실무학회) 2011 경찰연구논집 Vol.8 No.-

집회의 자유와 관련하여 각 국가는 개입이 필요한 것으로 보이는 집회 중에서 어떤 형태의 집회를 용인할 수 있고, 용인해야 하며, 어느 지점에서 집회로 인하여 개인 또는 공공의 법익을 엄격하게 제한할 것이냐는 물음에 직면한다. 특히, 입법자는 법익보호라는 임무수행을 위해 그에게 주어진 가장 강력한 수단인 형법을 어느 정도까지 적용해야 하는지 결정하여야 한다. 이 글은 독일의 시위범죄와 관련하여 독일형법전에 따른 형사법적 관점의 논쟁을 소개한다. 거론되는 주요 쟁점은, 첫째, 위법성의 맥락에서 본 독일형법 240조의 폭력개념이다. 둘째, 독일형법 제240조 제2항을 적용함에 있어서 소위 궁극적인 집회목적을 특별히 고려하여 비난가능성 여부를 검토하는 것이다. 나아가 실질적인 결론을 이끌어내기 위해 행정적으로 부수하는 어려운 문제를 고려하는 것이다. 셋째, 소요죄와 관련된 구성요건요소인 폭행, 다중이 집합하여, 합동력에 의하여 범한 행위의 정범 또는 공범에 대한 개념 정의와 해석의 문제이다. Im Hinblick auf die Versammlungsfreiheit steht jeder Staat vor der Frage, welche Form demonstrativer Betatigung seiner Burger er tolerieren soll und muss, und wo Rechtsguter einzelner oder der Allgemeinheit durch eine Demonstration so stark beeintrachtigt werden, dass ein Eingreifen notwendig erscheint. Insbesondere hat der Gesetzgeber zu entscheiden, inwieweit er bei der Wahrnehmung der Aufgabe des Rechtsguterschutzes zu dem scharfsten ihm zur Verfugung stehenden Mittel, dem Strafrecht, greifen soll. Im Zusammenhang mit demonstrationsdelikte in Deutschland stellt dieser Artikel die Debatte uber Demonstrationsdelikte aus strafrechtlicher Sicht nach dem StGB und ihre Auswirkungen vor. Im Einzelnen spricht Dieser Artikel folgendes an: 1. den Gewaltbegriff des § 240 StGB sowie im Rahmen der Rechtswidrigkeit. 2. die Verwerflichkeitsklausel des § 240 Abs. 2 StGB unter besonderer Berucksichtigung der sog. Fernziele. Weiter wird Dieser Artikel die schwierige Frage einer etwaigen Verwaltungsakzessorietat skizzieren, um abschliessend ein Zwischenfazit zu ziehen. 3. Bei dem Landfriedensbruch wird Dieser Artikel dann einige Probleme der Tatbestandsmerkmale Gewalttatigkeit, aus einer Menschenmenge heraus, mit vereinten Kraften als Tater oder Teilnehmer aufzeigen.

공공부문 IT 아웃소싱 의사결정 요인 도출:델파이 방법

윤성철(Sung Chul Yoon),이슬(Seul Lee) 한국IT서비스학회 2003 한국IT서비스학회지 Vol.2 No.2

To improve the quality of the services and to concentrate on the core capability, in public sector the IT outsourcing is recently being vitalized by the institutional support of the government for the entrusting non-government. Because the lots of general studies so far have simply focused on indicating fragmentary factors i.e. economical factors, risk factors, system factors, or induction objects, etc., they are insufficient in making the practical decisions, therefore we indicated systemized model extending over the whole range of the IT outsourcing to support substantial decision makings, and assorted 4 categories and drew considerable 55 factors from the literature study to materialize the previously considerable factors at each decision making stage. And the principal factors were drawn from each decision making category by a group of 11 experts. Besides, a henceforth plan for the application was also presented through an actual example of the IT outsourcing decision making process of ‘M’, a public enterprise.

철도차량 재질의 특성 연구

윤성철(Sung-Cheol Yoon),박성혁(Sung-Hyuk Park) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

Loading tests were conducted in the carbody of the railroad car to check the structural strength of the body of the railroad car. The objective of this study is to evaluate whether or not the carbody of a railroad car under the maximal strength is safe. The carbody of rolling stock is a principal structure that supports major equipment of the underframe and the freight. Therefore, the strength evaluation of this structure is important. Both structural analysis and loading test were performed under the loading condition. Prior to the evaluation of structural strength, finite element method software was used for structural analyses on stress distribution in a carbody of a railroad car. The actual loading tests were conducted.