• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.245-245
• /
• 2015

Cu(In,Ga)Se2 (CIGS) 박막 태양전지는 높은 효율과 낮은 제조비용, 높은 신뢰성으로 인해 박막 태양전지 중 가장 각광받고 있다. 특히 유리기판 대신 가볍고 유연한 철강소재나 플라스틱 소재를 이용하여 발전분야 외에 건물일체형, 수송용, 휴대용등 다양한 분야에 적용이 가능하다. 이러한 유연 기판을 이용한 CIGS 태양전지의 개발을 위해서는 기판의 특성에 따른 다양한 공정개발이 선행되어야 한다. 특히 CIGS 태양전지에서는 Na의 역할이 매우 중요한데 유연기판의 경우 이러한 Na이 없을 뿐만 아니라 철강기판의 경우 Fe, Ni, Cr등의 불순물이 확산되어 흡수층의 특성을 저하시켜 효율을 감소시킨다. 따라서 이러한 철강 기판의 경우 불순물의 확산을 방지하는 확산방지막이 필수적이다. 또한 플라스틱기판의 경우 내열성이 낮아 저온에서 공정을 진행해야하는 단점이 있다. 이러한 유연기판의 특성을 고려하여 본 연구에서는 유연기판으로 STS 430 stainless steel과 poly-imide를 이용하여 특성 개선을 진행하였다. 먼저 stainless steel과 Poly-imide, soda-lime glass, coning glass의 기판을 이용하여 기판에 따른 흡수층의 특성을 비교 분석하였으며 stainless steel 기판을 이용하여 확산 방지막의 유무 및 두께에 따른 흡수층 및 소자의 특성을 분석하였다. 이때 확산 방지막은 기존 TCO 공정에서 사용되는 i-ZnO를 사용하였으며 RF sputter를 이용하여 50~200nm로 두께를 달리하며 특성 비교를 실시하였다. 이때 효율은 확산방지막을 적용하지 않았을 때 약 5.9%에서 확산 방지막 적용시 약 10.6%로 증가하였다. 또한 poly-imide 기판을 이용하여 $400^{\circ}C$이하에서 흡수층을 제조하여 특성평가를 진행하였으며 소자 제조 후 효율은 약 12.2%를 달성하였다. 모든 흡수층은 Co-Evaporation 방법을 이용하여 제조하였으며 제조된 흡수층은 SEM, XRF, XRD, GD-OES, PL, Raman등을 이용하여 분석하였으며 그 외 일반적인 방법을 이용하여 Mo, CdS, TCO, Al grid를 제조하였다. AR 코팅은 제외 하였으며 제조된 소자는 솔라 시뮬레이터를 이용하여 효율 특성 분석을 실시하였으며 Q.E. 분석을 실시하였다.

• Journal of the Korean Society of Costume
• /
• v.39
• /
• pp.79-89
• /
• 1998

This study was carried out the effect of stability and color extract for it's condition in the curcuma L.. dyeing. The stability is to investigate the absorbance of the curcumin, one of the major yellow pigments and the stability regarding the effect of light, oxygen temperature and pH. The dyeing condition is compared the effect of mordanting condition and the best way to extract pigment and analysed through the color-fastness rating, color-difference value test. The main results obtained are summarized as follows ; 1.The best and proper solvent to extrect curcumin pigment was a ethanol and a distilled water. 2. The light effect indicated that the absorbances of solution in absence of ligh was more stable. 3. The oxygen(O2) effect to curcumin show-ed that the condition in the absence of O2 was more stable than that in presence of O2 4. The temperature showed that the absorbnace was best stable in4$^{\circ}C$ and less changed at $25^{\circ}C$ 5. The curcumin-etanol solution was stable in pH 2~4. 6. Generally color-fastness rating to silk, wool and cotton indicated that crocking C.F. and perspiration C.F. were more than 3rd grade and dry cleaning C.F. was more than 4th grade. But light color-fastness and washing color-fastness were very poor. 7. To make good color fastness, the mordan-ting treated group and the pre-mordant conditions were more effective than others 8. When compared with color-difference value test indicated that the silk was looks like more reddish and bluish color and than the wool and cotton were greenish and bluish. As a mordant, A(C2H4OH(COOH3) and D(K2Cr2O7)were more effective to make green-ish color in the silk and the reddish color was abtained by B(Al.K(SO4)2.12H2O) and C(FeSO4.7H2O).

• Transactions of the Korean hydrogen and new energy society
• /
• v.21 no.6
• /
• pp.500-506
• /
• 2010

The metal monolith catalyst coated with 15wt% Ni/$MgAl_2O_4$ is applied to the natural gas steam reforming for hydrogen production. To address the improvement of adherence between metal monolith and catalyst coating layer, the pre-calcination temperature as well as the coating conditions of $Al_2O_3$ sol are optimized. When the Fe-Cr alloy monolith is pre-calcined at $900^{\circ}C$ for 6 h, $Al_2O_3$ layer was formed uniformly on the entire surface of the metal substrate. It is seen that the formation of $Al_2O_3$ layer on the monolith surface is essential for the uniform coating of $Al_2O_3$ sol onto the monolith substrate. The monolith catalyst coated with 10wt% $Al_2O_3$ sol shows high $CH_4$ conversion and good thermal stability as compared with the monolith catalyst without $Al_2O_3$ sol coating under severe reaction conditions with high GHSV of 30,000 $h^{-1}$ at $700^{\circ}C$. In addition, the metal monolith catalyst shows higher catalytic activity and better thermal conductivity than 15wt% Ni/$MgAl_2O_4$ pellet catalyst.

• Korean Journal of Environmental Biology
• /
• v.27 no.4
• /
• pp.353-362
• /
• 2009

This study attempted to compare the litter decomposition rate of Arundinella hirta and Miscanthus sinensis var. purpurascens which collected from serpentine soil acting potentially toxic concentration of heavy metals and non-serpentine soil by using the microcosm method for 192 days under constant humidity and $23^{\circ}C$. The contents of Ni, Fe, Mg and Cr in the serpentine and nonserpentine soil originated litter showed high differences between them. The litter samples from serpentine site have lower C/N than non-serpentine litter, but the soluble carbohydrate content was shown almost similar between two plant litter. The mass loss rates of leaf litter from serpentine area were slower than those from non-serpentine site. During the experimental period, the remained dry weight of A. hirta and M. sinensis var. purpurascens litter collected from serpentine site were 64.7%, 65.0% of initial dry weight and litter samples from non-serpentine site showed 54.2%, 50.7%, respectively. K and Na were leached rapidly at the initial decomposition periods, but Ca showed immobilization and other metal elements reserved at the decomposing litter for a long time. The decomposing A. hirta litter from non-serpentine soil showed higher values of $CO_2$ evolution, microbial biomass-C, and microbial biomass-N than those in serpentine soil originated litter acting nutrient stresses and exhibited rapid decay rate. The microbial biomass and microbial respiration of decaying litter were positively correlated with litter decomposition rate, and these relationships showed more rapid slope in non-serpentine soil originated litter than that in serpentine soil.

• Economic and Environmental Geology
• /
• v.28 no.1
• /
• pp.53-67
• /
• 1995

Geochemical characteristics of iron-related Ulsan granite was studied in comparison with the Cretaceous granitoids from the metallogenic provinces of copper, lead-zinc and lead-zinc/molybdenum in the Gyeongsang Basin, and the variation of cheminal compositions at the Ulsan granite/serpentinite contact was investigated. Ulsan granite is plotted in the regions of granite and granodiorite of Streckeisen's diagram. It shows differentiation trend of calc-alkali magma, and the magmatic evolution from granodiorite to granite is consistant with the general crystallization path of the Cretaceous the granitoids in Gyeongsang Basin. Differentiation index(D.I.) of Ulsan granite is 86~95, which is higher than those of Jindong granites (D.I.=45~70) and Onjongri granites (D.I.=67~84), and there are differences in the content of some major and trace elements between Ulsan granite and other Cretaceous granitoids. At the Ulsan granite/serpentinite contact $SiO_2$, $K_2O$, $Na_2O$, $Al_2O_3$, Rb, Sr, Ba which are abundant in Ulsan granite decrease toward serpentinite, while T.Fe, MgO, Ni, Cr which are abundant in serpentinite decrease toward Ulsan granite. Therefore, the geochemical characteristics of Ulsan granite is applicable to distinguish iron province from different metallogenic provinces where other Cretaceous granitoids occur in the Gyeongsang Basin, and it is possible to find serpentinite which was intruded by granite on the basis of chemical variations.

• New & Renewable Energy
• /
• v.16 no.1
• /
• pp.1-14
• /
• 2020

Liquid air energy storage (LAES) using gas liquefaction has attracted considerable attention because of its mature technology, high energy density, few geographical constraints, and long life span. On the other hand, LAES has not yet been commercialized and is being developed recently. Therefore, few studies have performed an economic analysis of LAES. In this study, the levelized cost of electricity was calculated and compared with that of other energy storage systems. As a result, the levelized cost of electricity of LAES was $371/MWh. This is approximately $292/MWh, $159/MWh, $118/MWh, and $3/MWh less than that of the LiCd battery, VRFB battery, Lead-acid battery, and NaS battery. In addition, the cost was approximately $62/MWh and $195/MWh more than that of Fe-Cr flow battery and PHS. Sensitivity analysis of the levelized cost of electricity according to the main economic factors was performed, and economic uncertainty analysis was performed through a Monte-Carlo simulation. The cumulative probability curve showed the levelized cost of electricity of LAES, reflecting price fluctuations in the air compressor cost, electricity cost, and standing reserve hourly fee.

• Journal of environmental and Sanitary engineering
• /
• v.17 no.2
• /
• pp.71-78
• /
• 2002

This study was conducted to evaluate the concentration distribution characteristics of air pollutants by the yellow sand from China. The concentrations and chemical properties of FPM contained in the yellow sand were compared with those of air pollutants when having no yellow sand in order to estimate the variation characteristics and the originated source of air pollutants moved by yellow sand. The concentrations of PM-2.5 and PM-10 contained in the yellow sand showed an increase of 2.3 to 2.7 times than usual, and the concentrations of NO2 and SO2 in the gaseous pollutants showed an increase of about 1.6 times by yellow sand, and thus the air contamination was much influenced by yellow sand phenomenon. The concentrations of inorganic elements contained in FPM from the yellow sand showed a higher concentration variation in the order of Al>Mg>Zn>Pb than usual. The concentration coefficient of air aerosol during the yellow sand period showed that Na, K, Ca, Mg and Fe were originated from natural source, and Pb, Cr, Cd, Cu and Zn were originated from artificial source for inorganic elements. The correlation analysis between FPM and inorganic elements showed in the descending order of Al>K>Pb>Mg, and thus the deposited amount of Pb was influenced by that of yellow sand. The average concentrations of PM-10 measured during the yellow sand period exceeded the Korea Air Environmental Standard and showed a excess rate of 3.4 times in the maximum but the average concentrations of PM-2.5 showed within the United States Air Environmental Standard.

• Korean Journal of Materials Research
• /
• v.20 no.4
• /
• pp.181-186
• /
• 2010

Since it was developed by Joseph Aspdin, cement has been a common construction materials up to the present time. However, there are trace constituents in cement clinker. One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The aim of the present study was to investigate the concentration of water-soluble hexavalent chromium in cement clinker by using industrial by-products. For that reason, raw materials were prepared to add different $SiO_2$, $Al_2O_3$, and $Fe_2O_3$ sources. After the raw materials such as the limestone, the sand and the clay, iron ore was pulverized and mixed, and the raw meal was burnt at about $1450^{\circ}C$ in a furnace with an oxidizing atmosphere. The part in the raw materials of the clinker was substituted with slag, sludge, etc. and this was used to manufacturing cement clinker. To investigate the water-soluble hexavalent chromium content in clinker, raw meal was prepared by changing the modulus, the type, and the content of clinker materials and tested concentrations of hexavalent chromium in the clinkers. To determine $Cr^{+6}$ formation of the clinker, tests were done with raw meals adding chromium by using different industrial by-products. Consequently because the chromium was to be included in the raw materials of the clinker, production of Portland cement clinker was included with the chromium. Also, the chromium was converted into hexavalent chromium in the burning process.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.6
• /
• pp.701-717
• /
• 2003

The objective of this study was to extensively estimate the air quality trends of the study area by surveying con-centration trends in months or seasons, after analyzing the mass concentration of PM-10 samples and the inorganic lements, ion, and total carbon in PM-10. Also, the study introduced to apply the PMF (Positive Matrix Factoriza-tion) model that is useful when absence of the source profile. Thus the model was thought to be suitable in Korea that often has few information about pollution sources. After obtaining results from the PMF modeling, the existing sources at the study area were qualitatively identified The PM-10 particles collected on quartz fiber filters by a PM-10 high-vol air sampler for 3 years (Mar. 1999∼Dec.2001) in Kyung Hee University. The 25 chemical species (Al, Mn, Ti, V, Cr, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, Ce, Pb, Si, N $a^{#}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$, C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$, TC) were analyzed by ICP-AES, IC, and EA after executing proper pre - treatments of each sample filter. The PMF model was intensively applied to estimate the quantitative contribution of air pollution sources based on the chemical information (128 samples and 25 chemical species). Through a case study of the PMF modeling for the PM-10 aerosols. the total of 11 factors were determined. The multiple linear regression analysis between the observed PM-10 mass concentration and the estimated G matrix had been performed following the FPEAK test. Finally the regression analysis provided source profiles (scaled F matrix). So, 11 sources were qualitatively identified, such as secondary aerosol related source, soil related source, waste incineration source, field burning source, fossil fuel combustion source, industry related source, motor vehicle source, oil/coal combustion source, non-ferrous metal source, and aged sea- salt source, respectively.ively.y.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2011.03a
• /
• pp.36-36
• /
• 2011

We synthesized new dye sensor based on indole compound. Through the UV-vis absorptions, we analyzed chemosensing properties to explain metal binding properties. The peak absorptions increased at 472 nm when added metal cations($Cd^{2+}$, $Cu^{2+}$, $Hg^{2+}$, $Fe^{2+}$, $Zn^{2+}$, $Ni^{2+}$ and $Cr^{3+}$) and gradually decreased the peak at 516 nm. Thus, this UV-Vis absorption behavior clearly showed the metal binding reaction. To measure energy level of used dye sensor, HOMO/LUMO energy value was calculated with cyclovaltagramm(CV) and using computational calculation method, in which we estimated the optimum structure of dye sensor. CV and computational calculation method, both compared to find suitable geometric structure. (with almost same energy values.) From the computational calculation, dye sensor has plane structure. So, Amine and ketone in the dye sensor faced each other and makes position to bind metal cations. In addition, these positions was supported pull-push electron system and generated MLCT process, when the dye sensor was bonded with the metal cations and resulted chemosensing properties. Through the electrochemical and computational calculation method analyze, we proposed the chemosensing principles that the dye sensor bind the metal cation between ketone and amine. Finally, the formation type of metal ion bindings was determined by Job's plot measurements.