습식공정을 이용한 ZnS:Mn²⁺계 QD의 합성 조건에 따른 광 특성 변화 연구

차지민,이윤지,문성철,이성의,Cha, Ji Min,Lee, Yoon Ji,Moon, Seong Cheol,Lee, Seong Eui 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.1

In this study, the physical and optical properties of $ZnS:Mn^{2+}$ Quantum Dot prepared by wet-process condition with Mn/Zn ratio was valuated. The powder characteristics and optical behavior were investigated through XRD, TEM and Photo spectrometer exicted by various UV light source. We found the main peak of ZnS (111) was shifted by 0.8 degree to low angle position with increasing stirring energy from 200 RPM to 600 RPM, which is thought to be the increase of lattice defects during wet process. The photo luminescence at 600 RPM shows also higher blue intensity which is well correlated with XRD results. With increasing Mn/Zn ratio, the PL intensity become higher and shifed by 8.5nm to right side, by the increment of substitutional $Mn^{2+}$ ions.

시간적 확장을 실천하는 추모 박물관 -과거, 현재 그리고 미래의 공존으로

차지민 ( Cha Ji Min ) 성균관대학교 인문학연구원 2023 人文科學 Vol.- No.89

박물관은 지금까지 주로 과거를 정리하여 보관하고 전시하는 공간으로 인식되어왔다. 이러한 인식 때문에 박물관은 현재와 미래라는 시간적 연결성 안에서 논의되지 못하고 있다. 따라서 본 연구는 추모 박물관에 존재하는 과거와 현재 사이의 단절에 집중하여 과거와 현재의 연결고리 역할을 하는 방문객들의 시선과 경험을 통해 박물관을 분석한다. 기존의 국내외 박물관 연구는 대체로 박물관 설립 배경, 전시 기획 그리고 실무자들의 역할에 관심을 집중할 뿐 방문객들의 경험에 관한 논의에는 소홀한 경향이 있다. 이러한 공백이 아쉬운 이유는 방문객들의 경험은 박물관이라는 공간 안에서만 독립적으로 발생하는 것이 아닌, 그들이 되돌아갈 사회와 밀접하게 연결되어 있기 때문이다. 또한, 방문객이야말로 박물관이 표방하는 교훈을 현실에서 실천하는 핵심적인 연결고리 역할을 하기 때문이다. 그러나 지금까지의 연구들은 박물관을 사회(현재)와 분리하여 분석하고 방문객의 목소리 역시 소외시키고 있다. 따라서 본 연구는 칠레 인권박물관(Museum of Memory and Human Rights)에서 저자가 시행한 방문객 인터뷰와 과거, 현재 그리고 미래라는 복합적인 시각으로 과거를 전시하는 미국의 유산 박물관(Legacy Museum) 그리고 우리나라의 전쟁과 여성인권 박물관의 사례를 살펴봄으로써 추모에 관하여 새롭게 접근하는 박물관의 사례를 소개한다. 이를 통해 저자는 기존의 추모 박물관의 전시 내러티브가 놓치고 있는 부분을 분석함으로써 추모 박물관 전시에 새로운 방향을 제안한다. Museums have been recognized as the passive spaces for mainly organizing, storing, and displaying the past. For this reason, the studies of museums have not been properly conduced in relation to the present and the future. In particular, despite the existence of a large number of museums, especially memorial museums, the message of “Never Again” only rings hollow inside the museum, and the horrific human rights suppression of the past on display is still repeated outside the museum. Recognizing this gap, this study focuses on the disconnection between the past and the present that exists in these memorial museums, and analyzes the museum by following the experiences of visitors who act as a bridge between the past and the present. Existing research on museums tends to focus mainly on three aspects: the exhibition, the background of planning an exhibition, and the role of practitioners. Thus, current studies neglect discussions on the experience of visitors. The reason why this gap is regrettable is that the experience of visitors does not occur independently within the space of the museum, but is closely linked to the society they will return. In addition, it is because the visitor serves as a key link to practice the lessons advocated by the museum in real life. However, studies so far have analyzed museums separately from society (present) and alienate the voices of visitors. Hence, starting with research of the existing museums, this paper discusses the museum from the visitor's perspective through the visitor interviews conducted by the author. The author expands the case of the museum from the United States Holocaust Memorial Museum by introducing the cases of new museums that practice an alternative exhibition that connects the museum from the past to the present and the future. Therefore, by introducing the exhibitions of the Legacy Museum in the United States and the War and Women's Human Rights Museum in South Korea, this study examines the missing parts of the existing memorial museum exhibitions and suggests a new direction for the memorial museum.

Thermal Reflow 공정 적용 Micro Pattern 형상 변화를 통한 광 향상 구조층 연구

성민호,차지민,문성철,유시홍,이성의,Seong, Min-Ho,Cha, Ji-Min,Moon, Seong-Cheol,Ryung, Si-Hong,Lee, Seong Eui 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.5

In this study, the change of optical characteristics was studied according to the micro optical pattern provided by photo lithography followed by thermal reflow process. The shape and luminance variation with micro pattern was evaluated by SEM and spectrometers. Also, we analyzed the luminance characteristics using the 3D-optical simulation (Optis works) program. As a result, we found that the radius of curvature(R) in micro pattern is decreased up to 77%($150^{\circ}C$) compared to the radius of curvature at the condition $100^{\circ}C$, which is caused by efficient reflow of organic material without chemical changes. The highest enhancement of brightness with optimum micro pattern was obtained at the condition of $120^{\circ}C$ reflow process. The brightness gain with optical micro patterns is more than 15% at the condition of R=16.95 um, ${\Theta}=77.14^{\circ}$ compared to original optical source. The results of light simulation with various radius of curvature and side angle of pattern shows the similar result of experiment evaluation of light behavior on optical micro patterns. It is regarded that the more effect on light enhancement was contributed by side angle which is effective factor on light reflection, rather than the curvature of micro-patterns.

Taguchi 법 및 만족도 함수를 이용한 DIS 공정에 의한 알로에의 농축 최적화

권혜미 ( Hye Mi Kwon ),차지민 ( Ji Min Cha ),허원 ( Won Hur ),이신영 ( Shin Young Lee ) 한국산업식품공학회 2013 산업 식품공학 Vol.17 No.1

The optimization of dewatering and impregnation soaking (DIS) process for a concentrated Aloe vera product was investigated using Taguchi method in combination with desirability function analysis. Polyethylene glycol (PEG) as osmotic agent was adopted, and soaking temperature (T), immersion time (t), PEG concentration (C), PEG molecular weight (MW), and thickness of Aloe vera leaf slice (x) were selected as affecting variables. L_16 (4^5) orthogonal array was designed by Taguchi method with four parameters such as water loss, solid gain, glucomannan, and anthraquinone contents as objective functions. An overall quality index was transformed from individual objective functions, and was optimized finally. The optimal setting for maximum overall desirability was obtained at 55oC (T), 2 hr (t), 40% w/v (C), 0.5 cm (x), and 4,000 Da. (MW). The obtained overall desirability was 0.7842. The order of affecting factors was T>C>x>MW?x>t and the experimental results under optimum condition were similar to the prediction of an overall desirability of 0.8384. Also, it was found that the optimized DIS condition could be reproduced for a minimally processed Aloe vera product with high quality.

알로에 베라의 DIS (Dewatering & Impregnation Soaking) 공정 중 물질 전달 동역학 및 미세구조에 미치는 온도의 영향

권혜미 ( Hye Mi Kwon ),차지민 ( Ji Min Cha ),허원 ( Won Hur ),이신영 ( Shin Young Lee ) 한국산업식품공학회 2013 산업 식품공학 Vol.17 No.2

알로에의 최소공정개발 연구의 일환으로 DIS(dewatering & impregnation soaking) 공정에 미치는 온도의 효과를 조사하였다. 삼투탈수는 분자량 4000의 PEG을 삼투제로 하여 이의 40%(w/v) 용액에 두께 0.5 cm의 알로에 잎 슬라이스를 넣고 간헐적으로 교반하면서 2시간 동안 수행하였다. 서로 다른 침지온도(25-55℃)가 DIS의 성능(수분소실 및 고형분 획득)에 미치는 영향을 현미경관찰에 의한 세포조직 구조의 경시변화를 모니터링하면서 조사, 비교되었고, 동역학적으로 분석하였다. 고온(55℃) 처리에서는 저온(25 and 35℃)에서보다 더 높은 수분소실을 보였으나 세포조직의 파괴를 동반하였다. 또, 품질지표값으로서의 glucomannan 함량은 세포조직구조를 잘 유지하였던 침지온도 35℃에서 얻어졌다. 얻어진 시료의 실온건조제품을 재수화시켜 조사하고 동역학적으로 해석한 결과, 재수화 동역학은 Peleg 및 Weibull 모델로 잘 설명할 수 있었다. DIS 제품은 DIS 처리하지 않은 제품에 비해 세포구조 및 재수화성질의 향상을 주어 적정온도하에서 DIS 처리함으로써 최소공정의 알로에 제품을 얻을 수 있음을 확인하였다. To enhance the performance of the DIS (dewatering & impregnation soaking) process for Aloe vera leaf slices, the effect of temperature on DIS was investigated. DIS performance (water loss, solid gain) at various temperatures (25℃-55℃) was analyzed and changes of cell tissue structures were monitored by microscopic examination. DIS was carried out with an immersion time of 0-2 h and a thickness of Aloe vera leaf slices of 0.5 cm using poly(ethylene glycol) of 40% (w/v) with a molecular weight of 4,000 Da as a hypertonic solution. Increasing immersion temperature showed higher levels of water loss. In addition, the microscopic structures of samples treated at higher temperatures (55℃) indicated more disruption than those of samples treated at lower temperatures (25 and 35℃). The highest level of glucomannan content was observed at the 35℃ of immersion temperature. The DIS sample treated at 35℃ for 2 h without any pretreatment was air dried at room temperature, and this dried sample showed both improved cell structure and rehydration property in comparison to that of the sample prepared without DIS. Peleg and Weibull models were found to be the most accurate for describing the rehydration kinetics of aloe samples.

알로에 한외여과 다당분획의 희석용액 특성

백진홍 ( Jin Hong Beak ),강은원 ( Eun Won Kang ),김성아 ( Sung A Kim ),차지민 ( Ji Min Cha ),이신영 ( Shin Young Lee ) 한국산업식품공학회 2013 산업 식품공학 Vol.17 No.4

Two fractions (permeate and retentate) from fiber free Aloe vera gel were prepared using an ultra-filtration (UF) system with a tubular ceramic membrane (MWCO of 50 kDa), and their dilute solution properties were investigated. The intrinsic viscosities of fiber free Aloe vera gel and the retentate and permeate fractions that were prepared by ultra-filtration were 18.48, 37.74, and 2.01 dL/g, respectively. UF aloe retentate as a polysaccharide rich fraction exhibited polyelectrolyte behavior showing a sharp decrease of intrinsic viscosity by the addition of NaCl. However, as its NaCl concentration increasing to 1 M, its intrinsic viscosity slightly increased due to conformational change caused by the high concentration of NaCl. On the one hand, the intrinsic viscosities of the dilute UF-retentate solution were exponentially decreased with increasing temperature, and the temperature dependency of its intrinsic viscosity showed a sharp discontinuity at 30℃ instead of a linear Arrhenius behaviour, indicating a variation of flow mechanism or network rearrangement of a molecular chain. The chain stiffness of polysaccharide rich fraction at bellow and above 0.5 M of NaCl addition was 0.048 and 0.515, respectively, showing different stiffenings and significant conformational change. The coil overlap parameter and critical concentration of UF-retentate were 3.0 and 0.08 g/dL, respectively.