• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.551-554
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• 2003

A novel geometric solution for uniform bend transition in a pi cell has proposed. In order to obtain the uniform bend transition, we applied hybrid domain structure to the edge of a LC cell by using ion-beam alignment method. As a result, we confirmed that the uniform bend transition has arisen from the edge to the center. From the proposed structure, we expect that the reliable and uniform bend transition can be achieved in the pi cell.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.536-540
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• 2004

A novel nematic liquid crystal (LC) cell with splay structure exhibiting wide viewing angle, fast response time and high transmittance at the same time has been developed. With rubbed homeotropic alignment in parallel directions, the device shows bend alignment in the absence of vertical electric field. However, with applied high voltage in a pulse form, the LC shows a optically compensated splay (OCS) orientation such that the mid-director is parallel to a substrate and at both surfaces the LCs are aligned vertically in parallel direction. In the device, the birefringence of the cell becomes tunable with applying voltage, i.e., the amount of light passed through the cell can be controlled by controlling the orientation of the LC. Since the OCS cell has a self-compensation structure such that the LC has a mirror symmetry along the mid-director, the device shows a wide viewing angle with only a single domain and a fast response time.

• Transactions on Electrical and Electronic Materials
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• 제4권6호
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• pp.17-20
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• 2003

This paper describes the effect of halogenic gettering during oxide passivation of commercial solar cell with the $N^{+}$-P-$N^{+}$ structure. In order to study the effect of halogenic gettering on $N^{+}$-P-$N^{+}$ structure mono-crystalline silicon solar cell, we performed conventional POCl$_3$ diffusion for emitter formation and oxide passivation in the presence of HCl vapors. The $N^{+}$-P-$N^{+}$ structure based silicon solar cells were found to have higher short circuit current and minority carrier lifetime. Their performance was also found to be superior than the conventional $N^{+}$-P-$N^{+}$ structure based mono-crystalline silicon solar cell. The cell parameters of the $n^{+}$-p-$p^{+}$ and $n^{+}$-p-$n^{+}$ structure based cells, passivated by HCl assisted oxidation were measured. The improvement in $I_{sc}$ was attributed to the effect of the increased diffusion length of minority carriers, which came from the halogenic gettering effect during the growth of passivating oxide. The presence of chlorine caused gettering of the cells by removing the heavy metals, if any. The other advantage of the presence of chlorine was the removal of the diffusion induced (in oxygen environment) stacking faults and line defects from the surfaces of the silicon wafers. All these effects caused the improvement of the minority carrier lifetime, which in-turn helped to improve the quality of the solar cells.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1867-1875
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• 2011

이 논문에서는 저면적 256-point FFT 구조를 제안한다. 저면적 구현을 위하여 CSD(Canonic Signed Digit) 곱셈기 방식을 채택하여 구현하였다. CSD 곱셈기 방식을 효율적으로 적용하기 위해서는 곱셈연산의 가지 수가 적어야 하는데, 여러 알고리즘을 조사한 결과 Radix-$4^2$ 알고리즘이 곱셈연산의 가지 수가 적음을 발견하였다. 따라서 제안 구조는 Radix-$4^2$ DIF 알고리즘과 CSD 곱셈기 방식을 사용하였다. 즉 Radix-$4^2$ 알고리즘을 사용하여 4개의 스테이지에서 사용되는 곱셈연산의 가지 수를 최소화한 후에 각각의 곱셈연산 블록은 CSD 곱셈기를 사용하여 구현하였다. CSD 곱셈기 구현에서 공통패턴을 공유하여 덧셈기의 수를 줄일 수 있는 CSS(Common Sub-expression Sharing) 기술을 사용하여 구현면적을 더욱 감소시켰다. 제안된 FFT 구조를 Verilog-HDL 코딩 후 합성하여 구현한 결과, Radix-4를 사용한 구조와 비교하여 복소 곱셈기 부분의 29.9%의 cell area 감소를 보였고 전체적인 256-point FFT 구조에 대한 비교에서는 12.54% cell area 감소를 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.557-560
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• 2008

The main goal of this work is to fabricate light emitting diode (LED) module and apply it to mobile handset. We first fabricated the blue-color LED based on the AlInGaN cell structure with size of $200\;{\mu}m\;{\times}\;200\;{\mu}m$. Also we proposed a new $1.0\;mm\;{\times}\;0.5\;mm$ (1005size) packaging procedure for the LED cell. Thus the overall dimension of our LED cell was as small as $1.0\;mm\;{\times}\;0.5\;mm\;{\times}\;0.4\;mm$ ($W\;{\times}\;L\;{\times}\;T$). As far as we knew it was the first time that this small LED cell dimension had been fabricated and operated.

• Applied Microscopy
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• 제22권1호
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• pp.15-32
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• 1992

This study was an attempt to investigate and compare the fine structure of small cells in the space of Disse of various animal livers. All animal livers contained small cells with or without lipid droplets and the one with lipid droplet seemed to be more developed and show an abundance of activity in function. The fine structure of the small cells observed in the nonmammals was similar to that of Ito cell in the mammal. The electron density of the small cells was similar to that of other cell types in the same animal liver. The cisternal dilation of rough endoplasmic reticulum and Golgi apparatus was more predominant in the mammalian Ito cells. In the nonmammalian, aquatic vertebrates, however, lysosomes and filaments are much more abundant in the Ito cell and its abundant cytoplasmic processes rich in filaments were usually extended between the parenchymal cells. The disparity in size of organelles and numbers of lipid droplets in the small cells showed a tendency similar to those of other cell types in the same animal. From these results, it is considered that the small cells in the space of Disse is a Ito cell and the Ito cell without lipid droplets differentiates into the one containing lipid droplets according to the characteristics of the different animals respectively, and that the Ito cells in the mammals are more active in metabolic function, while those in the nonmammalian aquatic vertebrates are abundant in support of parenchyme.

• 반도체디스플레이기술학회지
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• 제13권2호
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• pp.29-35
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• 2014

In this study general solar cell production process was complemented, with research on improvement of solar cell efficiency through surface structure and thermal annealing process. Firstly, to form the pyramid structure, the saw damage removal (SDR) processed surface was undergone texturing process with reactive ion etching (RIE). Then, for the formation of smooth pyramid structure to facilitate uniform doping and electrode formation, the surface was etched with HND(HF : HNO3 : D.I. water=5 : 100 : 100) solution. Notably, due to uniform doping the leakage current decreased greatly. Also, for the enhancement and maintenance of minority carrier lifetime, antireflection coating thermal annealing was done. To maintain this increased lifetime, front electrode was formed through Au plating process without high temperature firing process. Through these changes in two processes, the leakage current effect could be decreased and furthermore, the conversion efficiency could be increased. Therefore, compared to the general solar cell with a conversion efficiency of 15.89%, production of high efficiency solar cell with a conversion efficiency of 17.24% was made possible.

• Design & Manufacturing
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• 제14권2호
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• pp.1-6
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• 2020

Recently, research and commercialization related to the field of cell-based therapeutic drug development has been actively conducted. In order to maintain cell viability and prevent contamination, refrigeration preservation devices, such as CRF (controlled rate freezer) or vapor type LN2 tanks have been developed. On the other hand, the storage container for liquid nitrogen tanks currently on sale minimizes the flow structure to prevent structural defects when stored in a liquid nitrogen tank having a high thermal conductivity than vapor nitrogen. If the cell-based treatment drug is stored in the gaseous LN2 tank as it is, the cell survival after thawing is greatly reduced. It was estimated that the existing storage container structure was a factor that prevented the rapid entry and circulation of gaseous nitrogen into the container. Therefore, this study intends to propose a new supercellular storage container model that can maintain the mechanical strength while maximizing the fluid flow structure. To this end, we estimated that the structural change of the storage container effects on the equivalent stress formed around the through-holes of them when exposed to a cryogenic environment using thermal-structural coupled field analysis. As a result of storage experiments in the gas phase tank of the cell-based therapeutic agent using the developed storage container, it was confirmed that the cell growth rate was improved from 66% to 77%, which satisfied the transportation standards of the FDA(Food and Drug Administration) cell-based therapeutic agent.

• Journal of Information Display
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• 제9권3호
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• pp.12-15
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• 2008

A bent electrode structure is proposed in the super in-plane switching (S-IPS) liquid crystal (LC), as it can reduce the response time without loss of transmittance in the bright state. The electrode angle in each position of the bent electrode was optimized to simultaneously achieve high transmittance and fast response time. The electro-optical characteristics of the proposed LC cell structure were experimentally compared with those of the conventional cell. It was observed that the response time became over 8% shorter without loss of transmittance when the proposed bent structure was applied.

• Journal of the Korean Wood Science and Technology
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• 제35권2호
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• pp.9-15
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• 2007

A comparative study of the structure and organization of the primary and secondary walls in different types of tropical plant waste fibers was carried out using transmission electron microscopy (TEM). The thickness of each layer was also measured using Image Analyzer. TEM micrographs haveconfirmed that cell wall structure of all six types of tropical plant waste fibers (empty fruit bunch, oil palm frond, oil palm trunk, coir, banana stem and pineapple leaf) has the same ultrastructure with wood fibre. The fibers consisted of middle lamella, primary and thick secondary wall with different thickness for different types of fibers. The secondary wall was differentiated into a $S_1$ layer, a unique multi-lamellae $S_2$ layer, and $S_3$ layer.