• 한국가구학회지
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• 제28권3호
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• pp.248-258
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• 2017

A study was carried out to observe the 1% aqueous safranine solution flow speed in longitudinal and radial directions of softwood Thuja orientalis L., diffuse-porous wood Gmelina arborea Roxb., and ring-porous wood Phellodendron amurense Rupr., Longitudinal flow was considered from bottom to top while the radial flow was considered from bark to pith directions. In radial direction, ray cells and in longitudinal direction tracheids, vessel and wood fiber were considered for the measurement of liquid penetration speed at less than 12% moisture contents(MC). The variation of penetration speed for different species was observed and the reasons behind for this variation were explored. The highest radial penetration depth was found in ray parenchyma of T. orientalis but the lowest one was found in ray parenchyma of P. amurense. The average liquid penetration depth in longitudinal trachied of T. orientalis was found the highest among all the other cells. The penetration depth in fiber of G. arborea was found the lowest among the other longitudinal cells. It was found that cell dimension and also meniscus angle of safranine solution with cell walls were the prime factors for the variation of liquid flow speed in wood. Vessel was found to facilitate prime role in longitudinal penetration for hardwood species. The penetration depth in vessel of G. arborea was found highest among all vessels. Anatomical features like ray parenchyma cell length and diameter, end-wall pits number were found also responsible fluid flow differences. Initially liquid penetration speed was high and the nit gradually decreased in an uneven rate. Liquid flow was captured via video and the penetration depths in those cells were measured. It was found that even in presence of abundant rays in hardwood species, penetration depth of liquid in radial direction of softwood species was found high. Herein the ray length, lumen area, end wall pit diameter determined the radial permeability. On the other hand, vessel and fiber structure affected the longitudinal flow of liquids. Following a go-stop-go cycle, the penetration speed of a liquid decreased over time.

• Korean Chemical Engineering Research
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• 제54권1호
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• pp.135-139
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• 2016

본 연구에서는 무기염을 첨가한 액-액 추출에 의해 식물세포인 바이오매스로부터 파클리탁셀 회수 방법을 획기적으로 개선하고자 하였다. 다양한 무기염(NaCl, KCl, $K_2HPO_4$, $NaH_2PO_4$, $NaH_2PO_4{\cdot}2H_2O$)을 이용하여 추출효율을 조사한 결과, NaCl에서 가장 낮은 분배계수(0.053)로 가장 높은 파클리탁셀 수율(~96%)을 얻을 수 있었다. NaCl을 이용한 액-액 추출에서 최적의 NaCl/용매 비와 메틸렌 클로라이드/메탄올 비는 각각 1%(w/v)와 26%(v/v)이었다. 또한 최적의 NaCl/용매 비와 메틸렌 클로라이드/메탄올 비에서 파클리탁셀 함량에 따른 영향을 조사한 결과, 순수 파클리탁셀 함량 0.066%(w/v)에서 가장 낮은 분배계수(0.053)로 가장 높은 수율(~96%)을 얻을 수 있었다. 기존 액-액 추출의 경우 총 3회의 추출로 파클리탁셀을 95% 정도 회수 가능한 반면 무기염을 이용한 방법의 경우 단 1회 추출로 대부분의 파클리탁셀을 회수(~96%) 가능하였다.

• 대한기계학회논문집A
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• 제33권5호
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• pp.469-473
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• 2009

We present high-voltage liquid-electrolyte microbatteries, inspired from the high-voltage generation mechanism of electric eels using serially connected multiple-cell arrays. In the microbatteries, we purge air into the electrolyte filled in a channel layer to isolate serially connected multiple cell arrays using three surface-tension valves (cell-front, outlet, and cell-end valves). Compared to the previous multi-cell stack or interconnection, present microbatteries provide a reduced multi-cell charging time. We have designed and characterized four different prototypes C1, C10, C20, and C40 having 1, 10, 20, and 40 cells, respectively. In the experimental study, the threshold pressures of cell-front, outlet, and cell-end valves were measured as $460{\pm}47$, $1,000{\pm}53$, and $2,800{\pm}170$ Pa, respectively. The average charging time for C40 was measured as $26.8{\pm}4.9$ seconds where the electrolyte and air flow-rates are 100 and $10{\mu}l/min$, respectively. Microbatteries showed the maximum voltage of 12 V (C40), the maximum power density of $110{\mu}W/cm^2$ (C40), and the maximum power capacity of $2.1{\mu}Ah/cm^2$ (C40). We also proposed a tapered-channel to remove the reaction gas from the cell chamber using a surface tension effect. The present microbatteries are applicable to high-voltage portable power devices.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.374-380
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• 2015

본 연구에서는 연료전지 캐소드 가스 확산층에서의 물의 영향이 연료전지 성능에 미치는 영향을 검토하기 위하여 연료전지 스택의 부하 변동에 따른 가스 확산층에서의 2상 현상의 구현이 가능한 동적 모델을 개발하였다. 개발된 모델에 대하여 2상의 영향에 의한 연료전지 부하변동에 따른 연료전지 스택 성능, 가스 확산층 내부에서의 물 증기와 산소의 농도분포, 가스 확산층의 두께 및 다공성이 연료전지 스택 전압에 미치는 영향에 대하여 검토하였다. 그 결과 본 연구의 범위 내에서 연료전지 스택 전압은 부하에 관계없이 2상 모델이 1상 모델보다 낮아짐을 알 수 있다. 촉매층 부근 가스 확산층에서의 산소 농도는 가장 낮고 물 증기의 농도는 가장 높음을 알 수 있었다. 또한, GDL의 두께가 두꺼울수록 GDL의 다공성이 작을수록 연료전지 스택 전압이 낮아짐을 알 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.506-508
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• 2007

We studied the nematic liquid crystal (NLC) alignment capability with a new alignment method utilizing an inkjet printed polyimide (PI) layer. A good, uniform LC alignment was achieved by the good PI printing using a new alignment method. The pretilt angle generated on the printed PI layer using the alignment method was almost the same as that on printed PI layer using rubbing alignment method. In addition, the good electro-optical performances of the new aligned twisted nematic (TN) cell with printed PI surface was obtained

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.109-112
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• 2016

We demonstrated an alternative electrically controlled birefringence liquid crystal (ECB-LC) system with ion beam (IB)-irradiated yttrium gallium oxide (YGaO) alignment films using a sol-gel process. The surface roughness of the films was dependent on the annealing temperature; aggregated particles on surface were observed at lower annealing temperatures, whereas a smooth surface could be obtained with higher annealing temperatures. Higher transmittance in the visible region was observed at higher annealing temperatures. The film had an amorphous crystallographic state irrespective of the annealing temperature. Furthermore, ECB-LC cell with our IB-irradiated YGaO film yielded faster response time when compared to ECB-LC cell with rubbed polyimide. Considering the fast response time and high transmittance, the IB-irradiated YGaO-base LC system is a powerful alternative application for the liquid crystal display industry.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.273-273
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• 2006

The encapsulation of volatile organic electrolytes is a major challenge in practical applications of the DSSC. Ionic liquid (IL) within polymer electrolytes is an attractive candidate for replacement. Here we used a low viscosity ionic liquid 1-ethyl 3-methylimidazolium thiocyanate in order to modify ionic conductivity (${\sigma}$) of polymer electrolyte ($PEO:Kl/l_{2}$) and hence DSSC efficiency. The doping of IL enhanced ${\sigma}$ and attained maximum (${\sigma}=7.62{\times}10^{-4}S/cm$) at 80 wt% of IL concentration. Beyond this it was harder to get stable films. XRD confirmed that the intensity of the sharp PEO crystalline peaks decreased when IL was added. The DSC studies confirmed the reduction in crystallinity by adding ionic liquid.The efficiency of solar cell using aforesaid material was 0.6 % at 1 sun irradiation.

• 전자공학회논문지
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• 제51권2호
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• pp.15-18
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• 2014

본 논문은 광스위치등에 사용되는 가변 광감쇠기를 위해 반사형 액정셀을 채용한 광감쇠기 구조를 제안하고 특성을 검토한다. 본 제안의 가변 광감쇠기는 반사형구조로 소형화가 가능하고 저전압구동이 가능하다. 광통신용 파장에 적합한 액정셀의 설계방법, 주변온도에 따른 동작특성, 광감쇠기의 응답특성 등을 검토하여 본 제안 구조의 유용성을 검증한다.

• 한국전기전자재료학회논문지
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• 제15권10호
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• pp.902-908
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• 2002

Homogeneously aligned nematic liquid crystal displays (LCDs) driven by in-plane or fringe field were known to exhibit wide viewing angle and appeared to be black in the off state. However, the existence of spacers inside the cell causes the deformation of the liquid crystal molecules. Such a deformation of the liquid crystal causes light-leakage in the dark state, which lowers contrast ratio of the display. We found that the light-leakage due to deformation of the LC director near the spacer mainly depends on the dielectric anisotropy and the ratio of elastic constants of the LC. In this paper, the mechanism on deformation of the LC near spacer is investigated by optical polarizing microscopy.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.150-152
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• 2004

We have studied contrast ratio of a homogeneously aligned nematic liquid crystal (LC) display as a function of the angle between the polarizer axis and LC director. The results show that a cell configuration in which a polarizer axis facing a light source coincides with a short LC axis has a better process margin in terms of high contrast ratio than that of the cell coinciding with a long LC axis.