디지털 시대의 사진재현의 모호성에 관한 연구 : '진실 게임'을 중심으로

신익기 경일대학교 디자인대학원 2004 국내석사

This study is based on the artworks displayed in my exhibition titled 'Truth or Dare.' With my artworks as exhibited through an exhibition 'Truth or Dare', this study intends to find out any photographic meaning about ironical 'reproducibility' of digital images and their 'fictionality' in virtual space. Furthermore, it also aims to investigate the application of digital images and their esthetic viewpoints with regard to the photography. On the other hand, this study attempts to complete the photographic meaning of digital images and their theoretical backgrounds from the angle of reproduction and expression, while suggesting any possible meaning of new expression techniques. As for methodology in this study, useful data and materials were collected and analyzed from relevant separate volumes, literatures and web-based documents, while the propensities of reference authors were compared and analyzed through a series of artwork collections. In addition, the reproduction and representation mode of digital images were investigated in two categories: Pictorialism in esthetic aspect and photomontage in formal aspect. The artworks as displayed in the exhibition 'Truth or Dare' mean an struggling attempt to overcome the conventional boundaries of photographs. For the sake of this attempt, the author adopted digital images using computer-aided manipulation. In combination with various images and spaces, my artworks tried to get over the photographic limitations by using the 'reproducibility' of existing photographs and virtual space. Techniques using computer-aided composition became regarded as new tools for any subjective expression of artworks. As a result, the photographic meanings of digital images as shown in artwork appear contrary to those of existing photographs. Digital photographs are expressed mainly by possibly feasible but non-existing virtual images. This point brings out great controversies about truth or false, but it didn't matter in my artwork, especially for personal and subjective expressions. Almost beyond conventional photographic characteristics, the artworks in the exhibition 'Truth or Dare' create new documents in current timing by means of certain actual time or past reminiscence. The expressability of existing photographs is not an appropriate way enough to represent certain past fact in combination with another real entity. As described above, incoming age may refer to an era of images without concerning any difference between reality and imitation. The ambiguity in the reproduction of digital images will be expectedly more and more graphically reflected and represented in the vortex of this awareness and change. The exhibition 'Truth or Dare' doesn't mean any negation of existing photography but mean a way of personal self-expression that reflects these historical circumstances as described above. Undoubtedly, the photography in the early 2000's comes to have an inevitable relationship with new digital pictorialism based on digital motion video. These points appear as an incoming matter of facts undeniable. Based on the Said exhibition, this study demonstrated that digital images were considered to be a present and future progressive form of ever-developing photography from now on. Moreover, as for me, it is expected that the identity and artistic significance of digital images will become developed and expressed in more and more refreshing forms.

폴리아크릴로니트릴계 탄소섬유의 물성 개선을 위한 전구체섬유의 개질 및 열안정화 특성에 관한 연구

신익기 부산대학교 대학원 2003 국내박사

폴리아크릴로니트릴(PAN) 전구체 섬유로부터 제조된 고성능탄소섬유는 다양하고 우수한 특성 때문에 자동차, 토목건축을 비롯하여 항공우주 등의 첨단산업에 이르기까지 산업전반에 걸쳐 광범위하게 활용되고 있으며, 이미 선진국에서는 새로운 응용을 보이는 탄소재료에 관한 연구가 활발하고 관련분야의 산업이 빠르게 성장하고 있다. 또한 생산원가가 저렴해짐에 따라 특수용도로 제한되어 있던 그 이용이 점차 일반화됨에 따라 원료 탄소섬유의 물성의 향상과 다양화에 대한 요구가 증가되고 있다. 탄소섬유의 물성은 원료조성의 선택으로부터 전구체 섬유의 제조기술과 탄화공정(열안정화, 탄화)에 이르기까지 각각의 공정에 영향을 받으며, 특히 전구체의 제조와 안정화공정이 지배적이므로 이것에 대한 연구와 개선이 요구된다. 본 연구는 고강도·고탄성 탄소섬유의 물성 개선과 보다 경제성 있는 제조조건 확립을 위한 기초연구로, 산성기를 포함한 공단량체의 사용에 의한 PAN 공중합체의 개질에 대한 중합기구 해석, 건·습식 방사시스템에 있어서의 전구체섬유의 형성연구 그리고 전구체섬유의 열안정화 특성에 대하여 조사한 결과 다음과 같은 결론을 얻었다. 1. 염화아연 수용액 속에서 산화-환원촉매를 개시제로 사용하여 PAN 공중합체를 제조할 때, 중합조건의 변화에 따른 P(AN-MA-IA) 3원 공중합체의 중합기구 및 그 특성을 조사한 결과, 중합율, 중합시간, 중합도 및 반응속도 등을 고려하면 최적의 단량체 농도는 약 10.0%이었다. 또한 전환율과 수평균 중합도 결과로부터 중합계가 안정되는 적정 중합시간은 6시간 정도를 나타냈다. 한편 본 중합계에서 합성한 고분자는 고분자용액에 있어 고분자의 강직성을 나타내는 α값이 약 0.82로 일반 의류용의 0.76보다 높은 값을 나타내었으며, 이 고분자를 방사하여 산화 고리화시키면 더욱 강력한 탄소섬유의 제조가 가능할 것으로 생각된다. 2. 염화아연 수용액 속에서 산화-환원촉매를 개시제로 사용하여 PAN 공중합체를 제조할 때, IA 공단량체의 함량변화에 따른 P(AN-MA-IA) 3원 공중합체의 중합거동 및 그 특성을 검토한 결과, IA 공단량체의 조성비가 증가할수록 공중합의 반응속도는 감소하였으며, IA 공단량체는 중합의 초기단계에 중합체에 빠르게 공중합되었다. 또한 적정 IA 공단량체 조성은 중합수율, 중합도, 산화온도 및 중합속도 등을 고려할 경우 약 2wt%가 적당할 것으로 생각된다. 아울러 IA 공단량체의 함량이 증가함에 따라 최대발열피크온도와 고리화개시온도가 감소되었다. 3. 탄소섬유의 제조공정에 있어서 우수한 성질을 부여할 수 있는 IA 공단량체를 포함한 PAN 공중합체에 있어서 용매계인 염화아연 수용액에서의 건·습식방사에 의한 섬유제조 및 그 물리적 성질을 조사한 결과, 건·습식방사에 가장 적합한 도프의 점·농도는 PAN공중합체 농도가 10.5%일 때의 약 500 poise 전후였다. 제조된 섬유의 인장특성과 치밀화를 나타내는 밀도 측정 결과로부터 염화아연수용액 응고욕의 적정농도는 약 33%이었다. 또한 겔상태에서의 적정 연신비는 3.2배였으며, 전체 연신비가 증가할수록 더욱 치밀화된 섬유제조가 가능하였다. 4. 이상에서 제조하여 얻은 PAN계 전구체 섬유를 이용하여 탄소섬유를 제조하는 과정에서 열안정화 및 탄화처리의 조건에 따른 조성 및 물성변화에 대해 고찰한 결과, 안정화 과정은 FT-IR 분석, DSC 분석, AI 값, 밀도 그리고 산화섬유의 조성분석으로부터 알 수 있었으며, 보다 완만한 안정화를 위한 3원 공중합체의 조성은 AN : MA : IA = 95 : 3 : 2였다. PAN 섬유의 안정화에 의한 고리화 반응은 섬유의 직경이 감소할수록 그리고 반응시간이 증가할수록 증가하였으며, 열안정화 공정에 있어서 초기단계인 2단계에서 빠르게 형성되었다. 전구체섬유의 안정화 정도를 나타내는 산소 함유량이 증가할수록 안정화 섬유의 밀도는 증가하였으며, 최종 섬유인 탄소섬유의 강도 및 탄성율 등을 고려하면 적정 산소함유량은 12% 전후였다. Carbon fiber is a material with excellent properties such as low density, high stiffness, good resistance toward chemical and environment effects, and ability to withstand high temperature as well as tensile strength and modulus. Therefore, the scope of their applications is widening to include areas such as automobiles, aerospace industry, electrical and electronic applications, geo-textiles, mining, medical, etc. Generally, the physical and mechanical properties of PAN-based carbon fiber are governed by the individual process conditions from the selection of raw materials and the preparation of precursor and carbonization(stabilization and carbonization), especially by the preparation of precursor and stabilization conditions to obtain high-performance carbon fiber. Therefore, it is necessary to research and develop the system to prepare a precursor and stabilization conditions. This study is concerned with the synthesis and characteristics of poly(acrylonitrile-methyl acrylate-itaconic acid) initiated by redox system using the sodium sulfite/sodium chlorate initiator in zinc chloride aqueous solution, variation of dry-jet-wet spinning parameters, and structure development during stabilization process to make high-performance carbon fiber from PAN fibers. In the free radical polymerization using ZnCl2 aqueous solution, the rate of polymerization increases linearly with increasing monomer concentration. The extent of conversion increases almost linearly with increasing polymerization time at the monomer concentrations of 8.0 wt%, 10.0 wt%, 12.0 wt% and 130 wt%, whereas an abrupt increase of the conversion rate is observed at higher monomer concentrations. In fact, the polymerization process at the monomer concentrations higher than 13.0 wt% was very difficult to control because the extensive exothermic polymerization reaction accelerates the polymerization reaction. This indicates that a self-acceleration and irregular chain transfer reaction take place during polymerization. Thus, the number of average degree of polymerization is decreased with the monomer concentration. It was found that optimum concentration of monomer is 10.0 wt%. On the other hand, the limiting conversion was increased with increasing monomer content. In addition to the nature of the comonomer, its proportion also causes a significant variation in the process of copolymerization and stabilization and the final carbon fiber properties. From the results of effect of comonomer content on the synthesis and characterization of poly(acrylonitrile-methyl acrylate-itaconic acid) initiated by redox system in zinc chloride solution, the conclusions were obtained as follows. As increasing the IA content, the conversion of acrylonitrile(AN) and the rate of polymerization were reduced. The comonomer content played a significant role on the stabilization process of the copolymer as well as the nature of the comonomer. The best result was obtained at about 2 mol% of IA. Since the itaconic acid(IA) comonomer is the potential initiator of cyclization, the introduction of IA comonomer into polyacrylonitrile(PAN) precursor can depress the onset and peak temperatures of the DSC exothermic peak obtained at oxidative heating. In the solution spinning, the most widely used technique for the spinning of PAN precursors is wet spinning, which is currently being replaced by dry-jet-wet spinning because the fiber produced by this technique has better mechanical properties. A study has been made of the dry-jet-wet spinning of fibers using 60% aqueous zinc chloride as solvent and 25-40% aqueous zinc chloride as non solvent. It was found that optimum viscosity of polymerized PAN solution dope for dry-jet-wet spinning is ?. 500 poise, as the polymer concentration is 10.5 wt%. The technological characteristics of dry-jet-wet spinning of polyacrylonitrile copolymer fibers lie in the fact that small streams of dope extruded from the die are allowed to pass first through a short distance of air gap(about 10mm) before entering the spinning bath for full coagulation. From the physical properties and density of the obtained fiber, the optimum concentration of coagulation bath is 33%. The PAN precorsors with better mechanical properties were prepared that the draw ratio is 3.2 times at gel state in the coagulation bath. The degree of dense of PAN precursor prepared by dry-jet-wet spinning is increased with increasing the total draw ratio. This work showed the importances of coagulation condition and stretch ratio, and fiber tenacity up to 10.5 g/d could be obtained with elongation of 11-16%. Individual fibers were evaluated on the basis of density and mechanical properties(tenacity and elongation etc.). The stabilization is considered to be the most decisive step because it largely governs the final structure of the fiber and hence its ultimate mechanical properties. In this study, a continuous stabilization process is used to make high-performance carbon fiber from polyacrylonittile(PAN)-based fibers. The effect of oxygen content of PAN-based fibers on the stabilization process and the properties of the resultant carbon fibers are investigated. In order to research the progress of stabilization reaction, FT-IR, elemental analysis, density, DSC, etc are used. Stabilization is carried out in air atmosphere from the 200 to 300? temperature range. An increase of PAN-based fibers diameter reduces the oxygen content during the continuous stabilization process. A higher oxygen content increase the density, tensile strength and modulus in the resultant carbon fibers. The most appropriate oxygen content in the stabilized fiber should be about 12%. Fibers having more than 12% oxygen content yield carbon fibers with inferior properties.

Studies on Biocatalytic Synthetic Membranes

신익기 The Graduate School of Pusan Nat'l Univ. 1991 국내석사

우수고객관리가 대출정책에 미치는 영향에 관한 연구 : 새마을 금고의 신용 대출을 중심으로

신익기 安東大學校 行政經營大學院 2003 국내석사

According to the change of the business environment and keen competition among banks the effective client strategies has become important. One of the effective client strategies is to enhance the relationship between superior clients and bank. Korean Federation of Community Credit Cooperative also has recognized the importance of the clients and made efforts to keep in continuous connections by maintaining the superior clients. This thesis suggested the research model which consider jointly the relationship among the management of the superior clients, performance of advance policy and business performance. The measurement model and the structural model had a chi-square of 106.601(p=0.008) with degrees of freedom 74, RMR of 0.059, GFI of 0.941, and AGFI=0.905 with a sample size of 233. The results indicate that all scales used in this study are adequate on the measures used and the structural model fits the data well. Test results are as follows: (1) the management of the superior clients had significantly and positively influence on the performance of advance policy, (2) the management of the superior clients had significantly influence on the business performance, and (3) the performance of the advances policy had significantly influence on the business performance. Therefore Community Credit Cooperative must manage superior clients effectively to contribute Cooperative's profitability. Test result of the research model depicts as <Figure 1>. In <Figure 1>, numbers above arrow line shows standardized path coefficients and numbers in parenthesis standard errors.