• 대한기계학회논문집A
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• 제31권3호
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• pp.380-387
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• 2007

We carried out an image analysis of living cells forming their contacts at the bottom of the cell culturing substrate. In order to visualize the contact area selectively, we adopted total-internal-reflection-fluorescence (TIRF) method, which can illuminate the specimen volume within only several hundred nano-meters above the substrate. From the fluorescent intensity of the TRF image, we could calculate the distance of the cell surface from the substrate. As a result, we visualized the origin of cell contacts, their movements, and the change of cell-contact type from the close-contact into focal-contact with information of its vertical displacement representing the temporal evolution process of the three-dimensional cell-surface-profile near the contact area during this metamorphosis.

• 한국재료학회지
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• 제13권5호
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• pp.313-316
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• 2003

The new epitaxial base cell as a high efficiency Si solar cell was fabricated and the effect of buried contact on the cell characteristics was investigated. In our experiments, the cell with buried contact showed the open circuit voltage of 0.62 V, the short circuit current of 40 mA, the fill factor of 0.7, and the efficiency of 10% under the incident light of AM-1 100 ㎽/$\textrm{cm}^2$. The insertion of buried contact in the epitaxial base structure brought the fabricated cell to the efficiency improvement of about 33%. The cell proposed in this paper has the structural superiority in the fabrication of high efficiency solar cell due to the carrier drift transport in the optical absorption region and the formation of back surface field by $p^{－}$ $p^{+}$ epitaxial base, and the reduction of emitter series resistance by n＋ buried contact.

• 한국발생생물학회지:발생과생식
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• 제16권4호
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• pp.329-338
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• 2012

The proliferation of embryonic cells or adult stem cells in tissue is critically regulated during development and repair. How limited the proliferation of cells, so far, is not much explored. Cell-cell contact proliferation inhibition is known as a crucial mechanism regulating cell proliferation in vitro and in vivo. In this study we examined the characters of mouse subcutaneous adipose derived stem cells (msADSC) whether they lost or get contact inhibition during in vitro culture. The characters of msADSC growth after confluence were analyzed using confocal microscope and the expression profiles of contact inhibition related genes were analyzed according to the morphological changes using real-time PCR method. msADSC showed overlapping growth between them but not after passage 14. The cell shapes were also changed after passage 14. The expression profiles of genes which are involved in contact inhibition were modified in the msADSC after passage 14. The differentiation ability of msADSCs to adipocyte, chondrocyte and osteocyte was not changed by such changes of gene expression profiles. Based on these results, it is revealed that smADSC were characterized by getting of strong cell-cell contact inhibition after passage 14 but the proliferation and developmental ability were not blocked by the change of cell-cell contact proliferation inhibition. These finding will help to understand the growth of adipose tissue, although further studies are needed to evaluate the physiological meaning of the cell-cell contact proliferation inhibition during in vitro culture of msADSC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.145-149
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• 1995

The metallization is the key to determining cell costs, call performance, and cell and system reliabiltiy. The Burled Contact Solar Cell (BCSC) was specifical1y desinged to be compatible tilth low cost, mass production techniques and avoid the conventional metallization problem. By using electroless plating trchniqeu, we performed this metallization inexpensively and reliabley, This paper presents the details of the optimization procedure of metallization schemes on laser grooved cell surface Commercially available Ni ,Cu, and Ag plating solutions were applied for the cell metallization. The application of those solutions on the buried contact front metalization has resulted in an cell efficiency of 18.5% The cell parameters are an open circuit voltage of 651 mV, short circuit current density of 38.6 mA/$\textrm{cm}^2$, and fill factor of 73.5%.

• 한국수소및신에너지학회논문집
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• 제13권4호
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• pp.313-320
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• 2002

The characteristics of the AISI bipolar plates have been investigated to replace the expensive graphite bipolar plates. It was found from the contact resistance evaluation of graphites, composites, and AISI that the contact resistance of AISI was the lowest, but it could approach to that of composites at higher compression forces. The single cell operation using the AISI bipolar plates revealed that the lower performance of the AISI single cell compared to the graphite one was due to not only the higher contact resistance but the flooding effect caused by high wettability of AISI. The performance of the AISI single cell could be improved if the channels were modified appropriately. The large size AISI single cell was operated to investigated the size effect on the performance.

• 한국전기전자재료학회논문지
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• 제24권5호
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• pp.345-350
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• 2011

This paper was carried about optimization for high efficiency of point contact solar cell. We have studied on the characteristics of power converter according to each parameter for the optimization for high efficiency of point contact solar cell on this study. We have 25.1352% of convert efficiency after adapt optimal parameters as mentioned in point body and superior conclusion is drawn by comparison with general efficiency has within 20%. At this time, the value of parameter is 100 um cell pitch, 0.01 um AR coating, 0.9 um N+ FSF thickness., etc. This study will continue to go on for optimization for efficiency in future, as it looks now, the results of this study would contribute to the business of high efficiency of point contact solar cell.

• 전기학회논문지
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• 제63권12호
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• pp.1671-1674
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• 2014

This paper presents a frequency-dependent cell impedance analysis chip for use in cancer and normal cell discrimination. The previous cell impedance analysis chips for flowing cells cannot allow enough time for cell-to-electrode contact to monitor frequency-dependent impedance response. Another type of the previous cell impedance analysis chips for the cells clamped by membranes need complex sample control for making stable cell-to-electrode contact. We present a new impedance analysis chip using the microchamber array, on which a PDMS cover is placed to make stable cell-to-electrode contact for the individual cell trapped in each microchamber; thus achieving frequency-dependent single-cell impedance analysis without complex sample control. Compared to the normal cells, the magnitude of NHBE cells is $60.07{\sim}97.41k{\Omega}$ higher than A549 cells in the frequency range of 95.6 kHz~2MHz and the phase of NHBE is $3.96^{\circ}{\sim}20.8^{\circ}$ higher than A549 cells in the frequency range of 4.37 kHz~2MHz, respectively. It is demonstrated experimentally that the impedance analysis chip performs frequency-dependent cell impedance analysis by making stable cell-to-electrode contact with simple sample control; thereby applicable to the normal cell and cancer cell discrimination.

• 한국전기전자재료학회논문지
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• 제24권12호
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• pp.1010-1017
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• 2011

The use of plated front contact for metallization of silicon solar cell may alternative technologies as a screen printed and silver paste contact. This technologies should allow the formation of contact with low contact resistivity a high line conductivity and also reduction of shading losses. A selective emitter structure with highly dopes regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing. When fabricated Ni/Cu plating metallization cell with a selective emitter structure, it has been shown that efficiencies of up to 18% have been achieved using this technology.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 추계학술대회 초록집
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• pp.156-156
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• 2009

High efficiency silicon solar cell technology based on planar technology has been improved by various kinds of process by using the wet etching process. In particular, the buried contact solar cell has been successfully studied. In the present work, a simplified process of the buried contact solar cell has been suggested to help one design effectively the high-efficiency solar cell.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1740-1745
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• 2004

A simplified resistor network model for electrical and mass transport in anode-supported planar solid oxide fuel cell (SOFC) was constructed in order to investigate the effect of interconnect rib geometry on the cell performance. For accurate potential calculation, activation and concentration over-potentials at the electrode/electrolyte interfaces were fully considered in this calculation. When contact resistance was not considered, the optimum interconnect rib length were calculated to be $0.1{\sim}0.2$ mm for 2 mm half unit cell for given operation conditions and properties. However, with realistic contact resistance, the interconnect rib length should be increased to provide larger contact area and thus to obtain better performance.