• 상하수도학회지
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• 제18권3호
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• pp.392-400
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• 2004

This research uses the $TiO_2$/UV process to verify the most suitable condition and possibility to dispose dyeing wastewater that contains pigment and a large amount of pollutants. For this, this research has enforced experiments that compare photo adsorption, photolysis, and photo catalyst oxidation reaction, and also evaluated and analyzed the change of pH and $TiO_2$ dosage, irradiation rates of ultraviolet rays and the dosage change and injection method of $H_2O_2$. According to the results of the dyeing wastewater experiment of storehouse catalyst that uses the new form of $TiO_2$, the photo catalyst oxidation reaction proved to be more effective than photo adsorption and photolysis; 35%, 21% in the case of $TCOD_{cr}$ and 39%, 28% in the case of chromaticity. Taking into consideration the reaction time, amount of photo catalyst reaction and irradiation amount of ultraviolet rays, the decomposition efficiency of pH change proved to be most effective at pH 4. On the whole, the acidity area proved to be effective in dyeing water exclusion than neutral and alkalinity areas. Having evaluated the influence of $TiO_2$ dosage, not only does the decomposition efficiency continuously improve as the $TiO_2$ dosage increases but the shielding effect does not occur also when the $TiO_2$ is at a fixed state. The influence of ultraviolet irradiation amount concluded in the result that as the ultraviolet irradiation amount increases the decomposition efficiency continually increased, but in the case of chromaticity when the irradiation amount was higher than 37.8mW/cm2 the removal efficiency is slowed remarkably. The influence of $H_2O_2$ dosage evaluation reached the results that although the decomposition efficiency increases with the increase of $H_2O_2$ dosage, when above 150mg (total dosage: 1200mg) $H_2O_2$ consumes OH radical itself and reduces the decomposition efficiency. Also in the case of the $H_2O_2$ injection method rather than injecting in the whole amount of $H_2O_2$ (1200mg) needed at the beginning all at once, injecting divided quantities of $H_2O_2$ whenever the electric current density falls below 10mgfl reduces the wases of OH radical due to an excess of $H_2O_2$ and in tum heightens the decomposition efficiency.

• Korean Chemical Engineering Research
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• 제48권6호
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• pp.737-740
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• 2010

높은 누설 전류와 문턱 전압의 이동은 비정질 실리콘(a-Si:H) 트랜지스터(TFT)의 단점이다. 이러한 특성은 게이트 절연체와 활성층 박막의 막 특성, 표면 거칠기와 공정 조건에 따라 영향을 받는다. 본 연구의 목적은 누설 전류와 문턱 전압의 특성을 개선하는데 목적이 있다. 게이트 절연체의 공정 조건에 대해서는 질소를 증가한 증착 공정 조건을 적용하였고, 활성층의 공정 조건에 대해서는 산소를 증가한 공정 조건을 적용하여 전자 포획을 감소시키고 박막의 밀도를 증가시켰다. $I_{off}$는 $65^{\circ}C$ 조건하에서 1.01 pA에서 0.18pA로, ${\Delta}V_{th}$는 -1.89 V에서 -1.22V로 개선되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.426.2-426.2
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• 2016

Numerous of researches are being conducted to improve the efficiency of $Cu_2ZnSnSe_4$ (CZTSe)-based photovoltaic devices, which is one of the most promising candidates for low cost and environment-friendly solar cells. In this work, we concentrate on the back contact of the devices. A proper thickness of $MoSe_2$ in back contact structure is believed to enhance adhesion and ohmic contact between Mo back contact and absorber layer. Nevertheless, too thick $MoSe_2$ layers that are grown during high-temperature selenization process can impede the current collection, thus resulting in low cell performance. By applying molybdenum nitride as a barrier in back contact structure, we were able to control the thickness of $MoSe_2$ layer, which resulted in lower series resistance and higher fill factor of CZTSe devices. The phase transformation of Mo-N binary system was systematically studied by changing $N_2$ concentration during the sputtering process. With a proper phase of Mo-N fabricated by using an adequate partial pressure of $N_2$, the efficiency of CZTSe solar cells as high as 8.31% was achieved while the average efficiency was improved by about 2% with respect to that of the referent cells where no barrier layer was employed.

• 해양환경안전학회지
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• 제18권3호
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• pp.287-293
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• 2012

본 연구는 수산 폐기물인 굴패각을 공조시스템의 수분 흡착제로 사용하기 위한 가능성을 실험을 통해 살펴본 기초적인 연구이다. 연구의 주된 목적은 굴패각의 제습성능과 열전소자의 냉각효과를 파악하는 것이며 본 연구를 통해 굴패각은 공조시스템 내에서 사용가능한 수분 흡착제로서의 성능을 충분히 가지고 있으며, 또한 냉각효과를 통해 흡착성능을 크게 향상시킬 수 있다는 것을 알았다. 본 시스템은 신재생에너지인 태양광을 이용하기 때문에 시스템의 구동에 필요한 다른 전원은 필요 없어 환경적으로도 매우 바람직한 연구이다.

• 한국정밀공학회지
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• 제27권3호
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• pp.135-141
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• 2010

Researchers continue to explore possibilities for expanding additive manufacturing (AM) technologies into direct product manufacturing. One limitation is in the materials available for use in AM that can meet the needs of end-use applications. Stereolithography (SL) is an AM technology well known for its precision and high quality surface finish capabilities. SL builds parts by selectively crosslinking or solidifying photo-curable liquid resins, and the resin industry has been continuously developing new resins with improved performance characteristics. This paper introduces a unique SL machine that can fabricate parts out of multiple SL materials. The technology is based on using multiple vats positioned on a rotating vat carousel that contain different photo-curable materials. To change the material during the process, the build platform is raised out of the current vat, a new vat with a different material is rotated under the platform, and the platform is submerged into the new vat so that the new material can be used. This paper introduces a new vat exchange mechanism, cleaning process, recoating process, resin leveling mechanism and process planning technologies for the implementation of multiple material SL. An overview of the system framework is provided and the system integration and control software is described. In addition, several multiple material test parts are designed, fabricated, and described.

• 청정기술
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• 제24권3호
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• pp.249-254
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• 2018

염료감응형 태양전지의 광전변환효율(${\eta}$) 향상을 위하여 수열합성한 $TiO_2$ 나노입자에 전기방사한 $TiO_2$, $SiO_2$, $ZrO_2$ 및 $SnO_2$ 나노파이버를 첨가하여 광전극에 적용하였다. $TiO_2$ 나노파이버를 첨가한 염료감응형 태양전지는 순수한 $TiO_2$ 나노입자에 비해 높은 전류밀도($J_{sc}$)를 나타내었고 이것은 나노파이버 구조로 인하여 염료에서 여기된 전지의 전달 특성이 용이하여 나타난 현상으로 생각된다. 또한 $SiO_2$ 나노파이버를 첨가한 염료감응형 태양전지의 경우, 순수한 $TiO_2$ 나노입자를 이용한 것에 비해 보다 높은 0.67 V의 개방전압($V_{oc}$)을 나타내었고 에너지 변환효율 또한 6.24%로 가장 높게 나타났다.

• 대한화학회지
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• 제37권6호
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• pp.549-554
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• 1993

티타늄 금속판을 공기산화와 수증기 산화하여 만든 Ti$O_{2-x}$ 박막을 시료로 사용하여 1M NaOH 용액에서 광전기화학적 성질을 연구하였다. 높은 온도에서 제조된 Ti$O_{2-x}$ 전극들은 낮은 온도에서 제조된 전극들보다 더 음의 값으로 주어지는 flat band potential($V_{fb}$)과 더 높은 donor density($N_D$)를 가졌다. 전극전위의 변화에 따른 광전류 측정과 Mott-Schottky plot로부터 얻은 $V_{fb}$는 -0.95 ∼ -1.1 V 사이에서 비슷한 값으로 주어졌다. 자외부 영역의 광을 완전히 차단하는 TiO2 단결정을 필터로 하여 가시부 영역의 광전류를 측정할 때 분해능이 좋은 slit를 사용한 경우 좋은 sub band gap 광반응을 볼 수 있었다.

• 한국자원식물학회지
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• 제32권3호
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• pp.207-219
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• 2019

Ultraviolet (UV) radiation is associated with the development of extrinsic skin aging. We performed in vivo assays in order to investigate the protective effect of a combination of grapefruit and rosemary extracts (cG&Re) on UVB-induced skin aging. The results indicated that cG&Re displayed elastase inhibitory activity in a dose-dependent manner. Topical application of cG&Re mitigated photo-aging related lesions such as skin erythema and thickening in photo-aged BALB/c mice dorsal skin, by preventing UVB-induced collagen degradation. Immunohistochemical analyses revealed that cG&Re stimulated SIRT-1 expression, and suppressed MMP-1 and $IL-1{\beta}$ expression. It was observed that expression of MMP-1 and -13 mRNA was downregulated in the cG&Re-treated group. Furthermore, cG&Re treatment drastically suppressed protein expression of MMP-1 and regulated the phosphorylation of p-38 kinase. As expected, oral administration of cG&Re resulted in the same SIRT-1, MMP-1, and $IL-1{\beta}$ expression patterns observed upon topical application of cG&Re in the UV-induced mice model. Overall, the current results demonstrated that cG&Re attenuated both the downregulation of MMP-1 expression and up-regulation of SIRT-1 expression, as well as decreased phosphorylation of MAPK in UVB-induced skin ageing mice model, suggesting that cG&Re might be used as an internal food ingredient for beauty-purposes as well as a functional food material.

• 전기전자학회논문지
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• 제23권3호
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• pp.947-953
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• 2019

본 연구는 가시광선, 적외선, 자외선 등이 대기 중의 물리입자에 의해 산란되는 빛(광자)을 받아서 발생하는 전하(전자 전공 쌍)를 집적하여 전압신호로 변환 및 증폭하는 전치증폭단과, 증폭된 신호의 파형을 semi-gaussian으로 보정하는 파형보정기 및 신호의 크기를 임의의 기준전압과 비교하여 신호 크기에 따른 펄스를 2진수 디지털 신호로 출력시키는 비교기와 계수기를 포함하는 물리입자 검출용 ASIC 칩 설계에 관한 것이다. 본 연구에서 제안한 구조 및 기능 블록을 갖는 ASIC은 Global Foundries의 0.18um standard CMOS 공정 변수를 사용하여 설계하였으며, 동 공정을 이용하여 칩을 제작하여 동작 및 성능을 검증 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.885-888
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• 2004

We have prepared and investigated the properties of photoinitiator-free photosensitive polyimide gate insulatos for organic thin-film transistors (OTFTs). The precursor was prepared from a dianhydride, 3,3',4,4'-Benzophenone tetracarboxylic dianhydride (BTDA) and novel aromatic diamine, 7-(3,5-diaminobenzoyloxy) coumarine (DA-CM). Photo-patternability of the polyimide precursor film and surface morphology of the films before and after photo-patterning process were investigated and negative pattern with a resolution of 50 ${\mu}m$ was obtained nicely. In addition, we have fabricated OTFTs with pentacene and photosensitive polyimide as a semiconductor and a gate insulator; respectively. According to the device geometry, the ${\mu}$, current modulation ratio and subthreshold swing of the devices were around 0.2${\sim}$0.4 $cm^2$/Vs, more than $10^5$ and around 3${\sim}$5 V/dec, respectively.