• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1155-1159
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• 1999

Thin film solar cells on a glass/$SnO_2$ substrate with p-SiC/i-Si/n-Si heterojunction structures were fabricated using a plasma-enhanced chemical-vapor deposition system. The photovoltaic properties of the solar cells were examined with varying the gas phase composition, x=$CH_4/\;(SiH_4+CH_4)$, during the deposition of the p-SiC layer. In the range of x=0~0.4, the efficiency of solar cell increased because of the increased band gap of the p-SiC window layer. Further increase in the gas phase composition, however, led to a decrease in the cell efficiency probably due to in the increased composition mismatch at the p-SiC/i-Si layers. As a result, the efficiency of a glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag thin film solar cell with $1cm^2$ area was 8.6% ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615) under 100mW/$cm^2$ light intensity.

• Polymer(Korea)
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• v.33 no.3
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• pp.191-197
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• 2009

We have investigated the effect of strong p-type organic semiconductor $F_4$-TCNQ-doped CuPc hole transport layer on the performance of p-i-n type bulk heterojunction photovoltaic device with ITO/PEDOT:PSS/CuPc: $F_4$-TCNQ(5 wt%)/CuPc:C60(blending ratio l:l)/C60/BCP/LiF/Al, architecture fabricated via vacuum deposition process, and have evaluated the J-V characteristics, short-circuit current ($J_{sc}$), open-circuit voltage($V_{oc}$), fill factor(FF), and power conversion efficiency(${\eta}_e$) of the device. By doping $F_4$-TCNQ into CuPc hole transport layer, increased absorption intensity in absorption spectra, uniform dispersion of organic molecules in the layer, surface uniformity of the layer, and enhanced injection currents improved the current photovoltaic device with power conversion efficiency(${\eta}_e$) of 0.16%, which is still low value compared to silicone solar cell indicating that many efforts should be made to improve organic photovoltaic devices.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.611-616
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• 2008

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.543-549
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• 2008

Distraction osteogenesis is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint(TMJ) have not been well documented. The TMJ is one of the most complex joint in the body and is composed of a fibrous surface layer, a proliferative zone, hypertrophic cartilage, and bone. The shape and role of the TMJ change and modify during a person's life-time. Possible complications that can arise after mandibular distraction include failure of the formation, failure of callus, infection, disturbance of TMJ and of occlusion. However, there are only a few reports on changes in the TMJ as a result of distraction osteogenesis. Hence, the goal of this study was to evaluate the change of the TMJ after experimental distraction of mandibular ramus in rabbit. We studied histological changes of mandibular condyle, articular disk and retrodiscal tissue, and also examined the collagen I gene expression and MMP-1 gene expression. The results were as follows. 1. In the histological staining, experimental condylar surface showed more thick fibrous articular layer and proliferative layer, compared with the control condyle and experimental articular disc showed thick and dense collagen fibers compared with the control disc. 2. In the collagen I and MMP-1 gene RT-PCR analysis, experimental discs showed increased collagen I expression compared with the control disc, while MMP-1 gene expression was decreased compared with the control disc. The retrodiscal tissue was almost equal expressions of the collagen I and MMP-1 genes compared with the control retrodiscal tissue. These findings suggest that histological and biomolecular changes occur in condyles and discs after unilateral mandibular distraction osteogenesis.

• Journal of the Optical Society of Korea
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• v.18 no.3
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• pp.256-260
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• 2014

Columnar-structured cesium iodide (CsI) scintillators doped with thallium (Tl) are frequently used as x-ray converters in medical and industrial imaging. In this study we investigated the imaging characteristics of CsI:Tl films with various reflective layers-aluminum (Al), chromium (Cr), and titanium dioxide ($TiO_2$) powder-coated on glass substrates. We used two effusion-cell sources in a thermal evaporator system to fabricate CsI:Tl films on substrates. The scintillators were observed via scanning electron microscopy (SEM), and scintillation characteristics were evaluated on the basis of the emission spectrum, light output, light response to x-ray dose, modulation transfer function (MTF), and x-ray images. Compared to control films without a reflective layer, CsI:Tl films with reflective layers showed better sensitivity and light collection efficiency, and the film with a $TiO_2$ reflective layer showed the best properties.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1544-1546
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• 1999

The fabrication process for ceramic fuel cell with a large electrode area was investigated. A cofired cell of two layer, electrolyte/anode, yielded a power of $200mW/cm^2$. Its performance loss was mainly due to iR drop in the anode side. The performance of the cofired of three layer. cathode/electrolyte/ anode, was much lower than that of two layer, which resulted from the large iR drop and overvoltage at the cathode side. Also a flat cell with a large area of $7.7{\times}10.8cm^2$ was fabricated successfully and tested using ceramic and metallic interconnectors. The large cell with metallic interconnectror showed a good performance of 0.6 V, 4.5 A.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.07a
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• pp.119-126
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• 2001

Chip-on-glass(COG) mounting of area array electronic packages was attempted by heating the rear surface of a contact pad film deposited on a glass substrate. The pads consisted of an adhesion(i.e. Cr or Ti) and a top coating layer(i.e. Ni or Cu) was heated by an UV laser beam transmitted through the glass substrate. The laser energy absorbed on the pad raised the temperature of a solder ball which is in physical contact with the pad, forming a reflowed solder bump. The effects of the adhesion and top coating layer on the laser reflow soldering were studied by measuring temperature profile of the ball during the laser heating process. The results were discussed based on the measurement of reflectivity of the adhesion layer. In addition, the microstructures of solder bumps and their mechanical properties were examined.

• Journal of the Korea Institute of Building Construction
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• v.7 no.2 s.24
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• pp.99-106
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• 2007

The purpose of this study presents in Relations between cracks in self-leveling material and quality of floor groundwork surface are experimentally examined. As the first stage, the experiment to observe cracks in self-leveling material constructed on floor groundwork made from various kinds of concrete was carried. As a result, following basic findings were obtained. First, observation of cracks should be continued until an increase in width of cracks stop, without constructing any finishing material. Second, degree of cracks may be indicated quantitatively by the product of length and width. Finally, Cracks and separation is not be influenced by specimen size. Based on these findings, the method of predicting cracks by evaluating surface layer quality of floor groundwork will be established.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1074_1075
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• 2009

A new type of dye-sensitized solar cells(DSCs) based on Ti-mesh electrode without using TCO layer is fabricated for high-efficient low-cost solar cell application. The TCO-less DSCs sample is composed of a [glass/ dye sensitized $TiO_2$ layer/ Ti-mesh electrode/ electrolyte/ metal counter electrode]. The Ti-mesh electrode with high conductivity can collect electrons from the $TiO_2$ layer and allows the ionic diffusion of $I^-/I_3^-$ through the mesh hole. Thin Ti-mesh ($\sim40{\mu}m$ in thickness) electrode material is processed using rapid prototype method. Electrical performance of as-fabricated DSCs is presented and discussed in detail.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.9-10
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• 2006

The patterning for the active layer of organic semiconductors is important to attain completely organic-based OTFTs(Organic Thin Film Transistors). We studied on possibility of the application of the conventional photolithography technique to pattern the organic active layer poly(3-hexylthiophene)(P3HT). Patterned P3HT-based OTFTs with Bottom Contact(BC) configuration were fabricated using the conventional photolithography. We achieved field-effect mobilities in the saturation regime ${\sim}1.2{\times}10^{-3}cm^2/V{\cdot}s$, $I_{on/off}$ ratios ${\sim}10^5$ in the subtractive method, ${\sim}8{\times}10^{-4}cm^2/V{\cdot}s$, $I_{on/off}$ ratios ${\sim}10^3$ in the additive one.