Crude MDI 의 정제 및 Monomeric MDI 의 안정화에 관한 연구

정종원,김영철,박남국 ( Jong Won Jung,Young Chul Kim,Nam Cook Park ) 한국공업화학회 1996 공업화학 Vol.7 No.3

Crude MDI를 정제하여 고순도의 Momeric MDI와 반응성이 양호한 Polymeric MDI를 얻기 위해 1차 및 2차 증류의 최적조건을 검토하였으며, Monomeric MDI의 변색 및 중합방지를 위하여 첨가제 사용 실험을 하였다. 또한 Polymeric MDI는 표준 Polyol system으로 우레탄 반응을 유도하여 반응성을 조사하였다. 1차 증류에서 증류분이 약 32wt%일 때 4,4`-MDI의 함량이 98wt% 이상으로 유지되었으며, 2차 증류에서는 2,4`-MDI의 혼입을 최소화하기 위해 초류분을 약 20wt% 분리하고 잔류분으로 약 9wt%를 남겼다. 환류비를 2이상으로 유지했을 때 최종 증류분인 Monomeric MDI의 응고점은 38.4℃ 이상으로 나타났다. Monomeric MDI는 매우 불안정하여 착색이 용이하고 자체 중합체를 형성한다. 따라서 이를 방지하기 위해 페놀계 1차 산화방지제 및 인계 2차 산화방지제, UV 흡수제, Hindered amine계 광안정제를 조합하여 사용하고, 중합방지제로는 Benzoyl chloride를 사용한 결과 45일 경과 후에도 색은 APHA 20이하이고 Dimer 생성율은 0.36wt% 이하로 유지되었다. The optimum conditions of the 1st and 2nd distillation had been investigated to obtaine a high quality monomeric MDI and fine reactive polymeric MDI by purification of crude MDI. Effect of additives on the monomeric MDI`s color change, dimerization and the reactivity of polymeric MDI with standard polyol system has been tested. When the monomeric MDI yield is approximately 32%, 4,4`-MDI content is above 98% in the monomeric MDI at the 1st distillation. When the separation ratio of initial portion and residue percentage, reflux ratio are set at respectively, approximately 20wt%, 9wt%, above 2 in order to minimize the content of 2,4`-MDI in monomeric MDI, the freezing point of final distilled monomeric MDI is above 38.4℃. Since the monomeric MDI is inherently unstable in the room condition, monomeric MDI easily changes it`s color and conducts self-polymerization reaction. To increse the stability of monomeric MDI, the composition of antioxidant, which is composed of phenolic 1st antioxidant, phosphorus 2nd antioxidant, UV absorbent and Hindered amine light stabilizer are used, and benzoyl chloride as antipolymerization agent test are that APHA color is less than 20, dimer content is remained less than 0.36wt% after 45 days storage of monomeric MDI.

바이오매스 나무재를 활용한 친환경 보강토의 특성 연구

정종원,안재훈,Jung. Jong-Won,Grau. Francisco,Ahn. Jaehun 한국방재학회 2014 한국방재학회논문집 Vol.14 No.3

세계적으로 많은 양의 바이오매스가 농업, 산림 및 에너지 자원으로 사용되고 있으나, 사용된 바이오매스의 많은 양은 여전히 단순 소각 후 폐기하고 있는 실정이다. 이는 자원의 낭비와 폐기 공간 부족 등의 문제를 초래하게 되며, 이에 따라 바이오매스 재의 처리 및 활용에 대한 방안은 시급하다고 하겠다. 따라서 바이오매스 재의 가장 큰 양을 차지하는 나무재를 건설재료로 활용할 수 있다면, 이는 자연자원의 보존과 쓰레기 저감에 크게 기여할 수 있을 것으로 판단한다. 본 논문은 바이오매스 재의 한 종류인 나무재의 건설재료로서의 적용 가능성을 타진하기 위하여, 나무재의 미세구조를 관찰하고, 나무재 및 보강토의 투수계수와 압밀특성을 분석하였다. 본 연구의 결과로부터 나무재의 함량을 소량으로 제한하는 경우에 지반재료의 압축성에는 큰 영향을 미치지 않으며 투수성을 크게 감소시키는 효과가 있음을 확인하였다. Biomass has been used as agriculture, forest and energy resources. The combustion of biomass matter becomes biomass ash that is dumped without control or disposed in landfills. Thus, the recycling or treatment of biomass ash is required. Wood ash is one of largest portion of biomass ash. Therefore, the recycling of wood ash in construction area will provide both new types of renewable energy sources and an environmental solution reducing the waste. The main objective of this study is to explore the physical, mechanical properties of Ottawa 20/30 sand, wood ash and mixture of them including Scanning Electron Microscope (SEM), hydraulic conductivity, and consolidation. It was observed that, small addition of wood ash to Ottawa 20/30 sand reduced the permeability significantly without increasing compressibility much.

우레탄형 변성 MDI 의 제조와 응용에 관한 연구

정종원,위승용,박돈희 ( Jong Won Jung,Seung Yong Wee,Don Hee Park ) 한국화학공학회 1996 화학공학의이론과응용 Vol.2 No.1

Luminescence Properties of Eu2+-and Eu3+-activated BaSi2O5 Phosphor Thin Films Grown by Using Pulsed Laser Deposition

정종원,양현경,문병기,최병춘,Jung Hyun Jeong,Soung Soo Yi,장기완,이호섭 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.5

BaSi2O5:Eu2+ thin films have been grown on Al2O3 (0001) substrate by using the pulsed laser deposition technique at a substrate temperature of 650 ˚C under various oxygen pressures. The enhancement emission mechanism of the blue to red color from BaSi2O5:Eu2+ phosphor to BaSi2O5:Eu3+ thin films by varying the oxygen pressure have been investigated. The crystallization, surface morphology and luminescent properties of the BaSi2O5:Eu3+ thin films depend on the oxygen pressure. The optimized emission was obtained at a 300-mTorr oxygen pressure, and that optimize emission may result not only from the improved crystallinity but also from the reduced internal reflections caused by the rougher surfaces. Moreover, the luminescent intensity and the surface roughness of the films as functions of the oxygen pressure exhibit similar behaviors.

임프란트 고정체와 지대주 직경의 차이가 응력분포에 미치는 영향

정종원,이청희,Jung Jong-Won,Lee Cheong-Hee 대한치과보철학회 2004 대한치과보철학회지 Vol.42 No.5

Statement of problem : Stress concentration on the neck bone affects the bone resorption, and finally the implant survival. Purpose: In order to examine the stress distribution on the neck bone and prosthesis abutment for implants, decreasing abutment sizes were used. Material and methods : Axisymmetric models were used to obtain the data required. These models were composed of 4mm implants with 3.4mm and 4mm abutments, 5mm implants with 3.4mm and 5mm abutments and 6mm implants with 3.4mm and 6mm abutments. All abutments were designed to received a 10mm high by 10mm diameter gold crown. Functional element analysis was used to obtain these results using data that consisted of 50 N vertical and 45 degree inclination forces. Results : 1. Changing the diameter of the abutment on the implant affects the effect of the inclination forces more than the effect of the vortical forces. 2. Changing the diameter of the abutment on the implant affect the effect of the inclination forces more than the effect of the vertical forces. 3. Experimentation showed that the larger diameter implants provided a decreased neck bone stress, whereas a larger diameter abutment provided a decrease marginal abutment stress. 4. Experimentation showed that the neck bone and abutment received more stress from inclination forces than vertical forces, Conclusions: By decreasing the size of the abutment on the implant we were able to diminishneck bone stress.

ICT기반 교육 ODA 사업의 성과평가도구 개발 및 타당화연구 : 첨단교실사업을 중심으로

정종원(Jung, Jong Won),김명랑(Kim, Myounglang) 한국교육방법학회 2018 교육방법연구 Vol.30 No.3

본 연구의 목적은 우리나라 교육 ODA 사업의 대표적인 사례 가운데 하나인 ‘ICT 활용 시범교실 구축.운영 지원 사업’의 성과 측정을 위해 타당한 평가준거 및 문항을 개발하고, 이를 활용하여 사업 목표달성의 예측력을 살펴보는데 있다. 이를 위해 ODA사업의 성과측정과 관련된 문헌고찰을 통해 성과측정의 3개 준거(ICT 자원의 적절성, ICT 교육 친화성 개선, ICT 리터러시 개선)와 해당 준거를 측정할 수 있는 18개 자기보고식 설문문항을 개발하고 전문가 검증을 통해 내용타당도를 확보하였다. 개발된 평가준거와 문항에 대해 첨단교실이 구축된 캄보디아, 아제르바이잔, 스리랑카, 파라과이 학생 543명을 대상으로 타당화를 위한 설문조사를 실시하고 탐색적 요인분석을 실시하였다. 더불어 측정 도구가 학습자의 ICT활용능력 향상 정도를 어느 정도 예측하는지 검증하기 위해 기초통계, 상관관계 분석, 회귀분석을 실시하였다. 연구 결과, 첨단교실 사업 성과 측정을 위한 3개 준거와 이를 측정할 수 있는 16개 문항의 타당성과 신뢰성을 검증하였다. 또한 첨단교실 사업 목표인 학습자의 ICT활용능력 향상에는 ICT 리터러시 개선, ICT 교육 친화성 개선이 긍정적 영향을 주는 예측변수로 유의미하게 나타났다. 본 연구의 결과는 증가하고 있는 ICT와 연계된 다양한 교육 ODA 사업의 체제적인 성과평가 모형의 개발과 실행에 대한 학문적, 실천적 논의에 활용될 수 있을 것으로 기대된다. The purpose of this study is to develop criteria and items for measuring outcomes for the innovative ICT-based classroom project, which is a educational ODA project of Korea, and verify its validity and outcome prediction. Relevant literature review was conducted to define criteria and items for measuring outcomes. The model consists of 3 criteria; relevance of inputs, improvements of ICT literacy, and improvements of ICT friendly instruction in innovative ICT-based classrooms. In order to verify its validity and reliability, a developed survey derived from the previous researches was conducted on 543 learners in Cambodia, Azerbaijan, Sri Lanka, and Paraguay, where innovative ICT-based classroom is operating. Content validity analysis, exploratory factor analysis were conducted. In addition, descriptive statistics, correlation, and regression analysis were performed using SPSS 20.0. The specific results are as follows. First, 3 criteria(relevance of inputs, improvements of ICT literacy and improvements of ICT in education-friendly) and 16 items were confirmed after verifying its validity and reliability. Second, the impacts of all 3 criteria(improvements of ICT literacy, improvements of ICT friendly instruction, and relevance of inputs) on achieving participated learners ICT literacy competencies were statistically significant. The result of study implies the importance of outcome-based ODA project design including the development and implementation of credible assessment tools. In addition, the result of this study could be considered as a exemplary case of ICT applied ODA project assessment in the field of education that is consistently increasing.

VR 기반 산업안전교육의 효과성에 관한 연구

정종원(Jong Won Jung),정기효(Kihyo Jung),정재욱(Jaewook Jeong) 한국공학교육학회 2023 공학교육연구 Vol.26 No.2

The purpose of this study is to explore the effectiveness of VR-based industrial safety education compared with conventional methods. For the study, three types of safety learning contents(VR-based learning, rule-based learning, and case-based learning) were developed and implemented with three college students groups. The results show that VR-based learning was effective in sustaining learning outcomes compared to other two conventional contents groups. In addition, participants perceived VR-based safety learning is attractive that facilitates their learning motivation and usefulness.

개항기 한글신문의 평등개념 연구

정종원(Jung, Jong Won) 한국사학회 2018 史學硏究 Vol.0 No.129

평등개념은 전근대의 다양한 신분, 계급들을 국민으로 통합시키는 작용을 하는 근대국민국가의 핵심적 개념이다. 이 글에서는 개항기에 평등개념 속에서 전통과 근대가 어떻게 교차하는지, 평등개념과 근대국민국가 형성이 어떻게 관계 맺는지를 파악하고자 하였다. 개항기 한글신문에 이르러 평등개념은 경험공간과 기대지평 사이의 괴리를 극대화하여 사회변화를 추동하는 힘을 가진 근대적 개념이 되었다. 그러나 그 내적논리에는 전통적 논리구조가 전승되고 있었다. 평등개념 안에는 근대국민국가 형성의 메커니즘이 담겨 있었다. 국제적 평등을 위해서는 감정공동체로서의 ‘국민’이 필요했고, ‘국민’을 형성하기 위해 국내적 평등으로 나아갔다. 그러나 이 구조는 국제적 평등이 국내적 평등을 양적으로도, 내용적으로도 압도하는 것이었다. 개항기 한글신문의 평등개념을 통해 개항기 한국의 사회적 인식구조에서 근대국민국가를 향한 움직임이 진행되었음을 알 수 있다. The idea of equality is a key concept of nation-state, which integrates people from different status and strata of premodern era into the modern nation. This study aims to analyze how the idea of equality became socially agreed epistemological structure during the Port Opening era, especially through series of Korean newspapers. During the Port Opening, Korean Newspapers represented the experience-space of equality through stimulating wordings such as shame and contempt, while constructed new horizon of expectations using the concepts of rights and Confucian reception. The idea of equality became a modern, dynamic concept by this gap between the experience-space and the horizon of expectation. The idea of equality was composed of international and domestic equality, and among them the international equality was more emphasized by the demand of independence of Korea. In order to mobilize nation for international equality, the nationalistic emotion must become a common sense by the achievement of domestic equality. By this the idea of domestic equality was expanded and strengthened. However its limit was also definite: the idea of domestic equality had a strong instrumentality for the international equality, and there were discriminative visions dividing world into civilization and savage among the idea of international equality.

바이오폴리머를 포함한 모래지반의 흙-습윤 특성곡선 연구

정종원(Jongwon Jung) 한국지반환경공학회 2018 한국지반환경공학회논문집 Vol.19 No.10

흙-습윤 특성곡선은 불포화토에서 물의 흐름, 다상유체에서의 상대투수계수, 그리고 흙의 강성 및 부피 변화를 이해하는데 필수적이다. 바이오폴리머는 미생물에 완전 분해가 가능한 자연에 무해한 친환경 물질이다. 따라서, 치토산, 폴리에틸렌 옥사이드, 잔탄검, 알지네이트염 및 폴리아크릴산 등과 같은 바이오폴리머가 지반복원, 지반성능향상 및 오일생산증진을 위해 연구되어왔다. 폴리아크릴산(polyacrylic acid)은 바이오폴리머의 일종으로, 유체의 흐름 특성 향상을 통하여 오일생산증진 및 지반복원 등의 분야에서 우수한 성능을 보여왔다. 따라서, 본 연구에서는 폴리아크릴산(polyacrylic acid)을 포함한 모래의 흙-습윤 특성곡선의 이해하기 위해서 실내시험을 수행하고, 이론적 모델의 매개변수 변화를 연구하였다. 그 결과, 폴리아크릴산(polyacrylic acid)의 농도가 증가함에 따라, 포화된 모래에 주입되는 공기의 주입 모세관압력이 증가함을 보이고, 높은 모세관압력에서의 잔류 함수비 역시 증가하고 있음을 보였다. 또한, 이론식 모델의 매개변수를 구하였으며, 이를 활용한 흙-습윤 특성곡선이 실내 실험 결과와 잘 일치하고 있음을 보였다. 따라서, 이론적 모델의 매개변수를 알고 있으면, 본 연구에서 활용된 폴리아크릴산(polyacrylic acid)이외의 바이오폴리머를 포함한 모래 지반의 흙-습윤 특성곡선이 예측이 가능함을 설명하였다. Soil-water characteristic curve, which is called soil retention curve, is required to explore water flows in unsaturated soils, relative permeability of water in multi-phase fluids flow, and change to stiffness and volume of soils. Thus, the understanding of soil-water characteristic curves of soils help us explore the behavior of soils inclduing fluids. Biopolymers are environmental-friendly materials, which can be completely degraded by microbes and have been believed not to affect the nature. Thus, various biopolymers such as deacetylated power, polyethylene oxide, xanthan gum, alginic acid sodium salt, and polyacrylic acid have been studies for the application to soil remediation, soil improvement, and enhanced oil recovery. PAA (polyacrylic acid) is one of biopolymers, which have shown a great effect in enhanced oil recovery as well as soil remediation because of the improvement of water-flood performance by mobility control. The study on soil-water characteristic curves of sandy soils containing PAA (polyacrylic acid) has been conducted through experimentations and theoretical models. The results show that both capillary entry pressure and residual water saturation dramatically increase according to the increased concentration of PAA (polyacrylic acid). Also, soil-water characteristic curves by theoretical models are quite well consistent with the results by experimental studies. Thus, soil-water characteristic curves of sandy soils containing biopolymers such as PAA (polyacrylic acid) can be estimated using fitting parameters for the theoretical model.

KB 사람 구강 편평 암세포에서 Lyophyllum shimeji로부터 분리한 단백질 추출물의 항암활성

정종원 ( Jong Won Jung ),문선민 ( Sung Min Moon ),박보람 ( Bo Ram Park ),김수관 ( Su Gwan Kim ),김진수 ( Jin Soo Kim ),김춘성 ( Chun Sung Kim ) 조선대학교 치의학연구원 2014 Oral Biology Research (Oral Biol Res) Vol.38 No.2

Purpose: To explore its potential anti-cancer effect, we examined whether or not extract of Lyophyllum shimeji could inhibit growth of KB human oral squamous cell carcinoma and investigated its anti-cancer mechanism. Materials and Methods: This study examined the anti-effects of protein extract from L. shimeji as well as its molecular mechanism of action on KB human oral squamous cell carcinoma. To determine whether or its mechanism is related to apoptosis, we performed DNA fragmentation, Western blotting, and LIVE-DEAD cell staining. Results: Treatment with extract from L. shimeji reduced cell viability of KB oral squamous cell carcinoma in a dose-dependent manner. Formation of a DNA ladder was observed by treatment with extract from L. shimeji. Western blot analysis showed that extract from L. shimeji induced activation of cleaved caspases-7 and -9 as well as cleaved poly-ADP-ribose polymerase. Furthermore, we confirmed that dead cell staining (red color) was significantly increased by extract from L. shimeji. Conclusion: L. shimeji exhibited cytotoxicity on KB humans oral squamous cell carcinoma, and its effect was mainly mediated by apoptosis. Thus, L. shimeji could be considered as a potential safe and effective chemotherapy agent for the treatment of oral cancer. In addition, these results suggest that extract from L. shimeji induces cell apoptosis through a mitochondrial caspase-dependent pathway in KB humans oral squamous cell carcinoma.