Diels-Alder반응을 이용한 Norbornene의 합성

Thesis (master`s)--서울대학교 대학원 :응용화학부,2003.This thesis is concerned with the synthesis of norbornene via Diels- Alder reaction of cyclopentadiene with ethylene. For this, we have carried out preliminary thermodynamic study to estimate the preferred reaction temperature on the basis of thermodynamic properties. The calculation indicates that the postulated range of the reaction temperature is 201-272oC. In thermal reaction, the reaction performance was influenced by temperature, pressure, solvent, and initial reactant concentration. Within the scope of the present study, the optimum conditions were found to be 260oC and 1000psi with aromatic solvent and low initial concentration of dicyclopentadiene. Although catalytic reactions have also been examined to probe the viability of the catalytic reaction under mild reaction conditions, it is revealed that catalytic activities were very low and thus it seems that the use of catalyst has little advantage over the corresponding thermal reaction. The kinetic study has been performed to calculate the kinetic parameters (reaction orders and rate constants) using the postulated kinetic mechanism. The kinetic model with the estimated parameters could predict the experimental results well. From the calculated parameters at various temperatures and pressures, the apparent activation energy value and reaction orders were obtained. The apparent activation energy of Diels-Alder reaction of cyclopentadiene with ethylene was found to be 59 ± 3 kJ/mole, and empirical orders of the reaction with respect to the partial pressure of ethylene and the concentration of cyclopentadiene were estimated to be 1.09 ± 0.03 and 0.84 ± 0.02, respectively.Maste

생체내 효소반응 규명을 위한 C-laveled thiamine의 합성과 항암, 항바이러스 약효를 가진 새로운 isonucleosides의 합성

Thesis (doctoral)--서울대학교 대학원 :화학과 유기화학전공,1996.Docto

Numerical and Experimental Research for Thrust Enhancement of Four Rotor Cyclocopter

학위논문(석사) --서울대학교 대학원 :기계항공공학부,2010.2.Maste

Joint identification of differentially expressed gene and phenotype associated genes

학위논문 (석사)-- 서울대학교 대학원 : 협동과정 생물정보학전공, 2013. 2. 박태성.The emergence of a wide variety of new techniques has led to the production of diverse types of biological data. Among them microarray technology has brought innovative changes in biological field and is still most commonly used in various research fields. For the last decade, many analytical methods and tools have been developed. In general, the detection of differentially expressed genes (DEGs) among different treatment groups is often a primary purpose of microarray data analysis. In addition, the association studies investigating the relationship between genes and the phenotype of interest such as survival time became also popular in microarray data analysis. Such association analysis provides the list of phenotype associated genes (PAGs). In this study, I consider a joint identification of DEGs and PAGs in microarray data analyses. The first approach is a naïve approach which detects DEGs and PAGs separately, and then identifies the intersection genes of PAGs and DEGs. The second approach is a hierarchical approach which detects DEGs first and then chooses PAGs among DEGs, or visa versa. I propose a new model-based approach for a joint identification of DEGs and PAGs simultaneously. Through a real microarray data analysis, I show that our model-based approach provides a more powerful result than the naïve approach and the hierarchical approach.Abstract Content List if Tables List of Figures 1. Introduction 1. 1. Microarray technology 1. 2. DEGs and PAGs 1. 3. Purpose of research 2. Materials and Methods 2. 1. Data 2. 2. DEG detection 2. 3. PAG detection 2. 4. Joint identification 3. Result 3. 1. DEGs 3. 2. PAGs 3. 3. Joint identification 4. Simulation study 5. Discussion 6. Reference Abstract(국문초록)Maste

Rubber clay-like fluffy fiber scaffolds

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CCPM applied Material Procurement Management Process to Shorten the Duration of Piping Construction : A Case Study on Petrochemical Plants

MasterThe objective of this study is to propose a piping construction delay prevention methodology for overseas petro-chemical plant projects execution, based on Critical Chain Project Management (CCPM). Owing to the fact that piping construction is a major part of any plant project and has important relationships with other aspects of the construction project, it is quite clear that an effective methodology for piping construction scheduling is essential. Results from recent studies reveal that the Program Evaluation and Review Technique and Critical Path Method (PERT/CPM) traditionally used for scheduling has critical limitations regarding resource scarcity, calculation of activity duration, and dealing with uncertainties. To overcome these limitations, the use of the Theory of Constrains (TOC)-based CCPM has been proposed to provide schedule buffer management. This study extends the knowledge of traditional resource buffer in CCPM toward material management to avoid shortage of piping materials and minimize delay at the project site. In this study, the performance of the proposed method was validated using two commercially available software tools: MS project and @Risk (stochastic simulation). This study uses data from a recently completed project and attempts to determine the appropriateness of the proposed method as a management technique for handling pipeline construction scheduling. In this study model, three major factors were considered as prerequisite conditions for the on-time completion of a piping construction project, namely effective use of limited number of welders, proper estimation of working time, and suitable work planning to ensure availability of materials. The following steps were implemented in the CCPM scheduling technique. First, welders were assigned according to the CPM-based technique without assigned to multiple tasks in the same period. Second, activity duration was adjusted considering the actual work time to complete a given task; the residual time (safety margin) was determined and inserted as the project buffer at the end of the project in accordance with CCPM technique. Finally, the extended resource buffer was inserted in the technique and processed using the proposed task implementation procedure. The results of the simulation show that the proposed CCPM method is effective in reducing the duration of piping construction when compared to the traditional PERT/CPM method. Compared to the CPM-based technique, the proposed method reduced the duration of the project (i.e. crude system unit) by approximately 35% for a 50% safety margin. The proposed material management method could provide an effective workflow to initiate piping construction related tasks on time. The proposed method could be successfully applied as a risk management technique for piping construction on the project site in the future. The study provides a useful platform to manage piping installation projects, eliminate potential project delay, and enable project teams to effectively utilize limited human and material resources using the CCPM technique combined with material management process.배관 설치 공사는 여러 공종과 선후행 관계를 가지며 플랜트 건설 프로젝트에서 큰 비중을 차지하고 있기 때문에 배관 설치 공사의 효율적인 공정 관리는 EPC (Plant) 프로젝트 관리의 필수적인 요소라고 말할 수 있다. 근래에 자원의 제약, 비효율적인 작업 기간 산정 그리고 불확실성에 대한 대처가 공정관리 기법에서 전통적인 방법으로 사용되었던 PERT/CPM 의 한계점으로 인식되며 이에 대한 많은 연구가 진행되어 왔으며 이러한 제약을 극복을 하기 위하여 Goldratt 박사는 자원의 경합 해결 및 버퍼 도입을 통한 TOC 기반의 CCPM 기법을 제안하였다. 본 연구는 효율적인 공정관리로 공사 완료 지연을 방지하기 위하여 기존 CCPM 기법을 플랜트 배관 공사 프로젝트에 적용하였고 기존 CCPM 기법에서 사용하던 자원 버퍼의 개념을 확장하여 배관 설치 공사의 작업 지연을 결정하는 가장 큰 요소인 자재 부족 문제를 해결하고자 하였다. 성공적인 배관 설치 공사를 위한 전제 조건으로 제한적으로 공급되는 용접 인력, 작업 기간의 적절한 산정 그리고 작업 시작 지연을 방지하는 자재 부족 문제 이 세가지 요인으로 규정하고 연구에 고려하였다. 본 연구는 다음과 같은 방법으로 CCPM 기법의 공정 분석 연구를 수행하였다. 첫째로 용접사를 CPM 기반 일정에 작업 중복없이 배치한다. 둘째로 작업 기간 산정 시 작업을 완료하기 위하여 CPM 기반으로 산정된 작업 기간에서 필요한 순수 작업 시간을 고려하여 작업 기간을 산정하고 나머지는 안전 여유 기간으로 CCPM 기법에 따라 프로젝트 일정 끝으로 배정한다. 마지막으로 확장된 자원 버퍼를 일정에 삽입하고 제안된 업무 프로세스를 통하여 수행될 수 있도록 한다. 분석 시, 현실적인 요소를 반영하기 위하여 안전 여유 기간을 줄여 작업 시간을 늘리는 방법으로 분석 케이스를 준비하였다. 연구 모델의 시뮬레이션 검증 결과, CPM 기반의 일정과 비교하여 CCPM 연구 모델은 50% 안전 여유를 고려한 일정 기준으로 35% 공기 절감 효과를 보였다. 또한 연구 모델에서 제안 된 현장의 배관 자재 관리를 위한 업무 절차는 리스크 관리에 효과적이고 배관 설치 공사에서 공기 연장을 피할 수 있는 유용한 현업 도구로 사용될 수 있고 버퍼 관리와 자재 관리 절차를 통하여 프로젝트 참여자들이 제한된 인력 관리와 배관 자재를 효율적으로 관리 할 수 있음을 확인하였다

Highly Deformable Electrospun Fibrous Clay with Three-Dimensional Porous Structure

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Synthesis of Surfactant Free SnS Nanoplates and Morphology Control in an Aqueous Solution

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Investigation of Conductive Networks Variations in Stretchable Electrodes by In Situ TEM and SAXS

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Highly Stretchable Gold Nanosheet Eelctrodes Patterned by Stamping Process

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