• 한국대기환경학회지
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• 제14권4호
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• pp.361-368
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• 1998

Acid rainwater samples were collected during 4 years from 1992 in Pusan area nearby seaside. Ionic composition of early and succeeding rainwater were investigated to identify emission sources. pH and Electronic Conductivity of samples were measured immediately after sampling. Major ion concentrations of rain samples were Na+, Ca2+, Mg2+, K+, NH4+, SO42-, NO3-, Cl- which were analyzed by ion Chromatography. 55% of early rainwater and 90% of succeeding rainwater were identified below pH 5.6. Because, Na+, K+, Ca2+ were washed mostly in early rainwater, as a result, pH values were increased by increasing rainfall amounts. It was studied that pH value was varied from ambient ion component, rainfall, and rain intensity. From the principal component analysis result, the dominant components of acid rainwater were Na+, K2+, Mg2+, Ca2+, the elements were contributed soil and marine source, the second components nuts -SO42-, SO4a-, NO3-, nuts -Ca2+ originated from man - made source.

• 대한환경공학회지
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• 제32권1호
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• pp.69-78
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• 2010

일반주택의 먼지오염실태를 연구하기 위하여 2009년 1월부터 2월까지 대구지역내의 도시지역(24곳) 및 농촌지역(24곳)의 일반주택 48가구를 대상으로 진공청소기에 포집된 먼지를 수거한 뒤 100 ${\mu}m$ 이하로 체거름하고 산추출한 후에 발암물질로 알려진 Cd과 Ni을 포함한 모두 14개 원소(Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, Zn)를 ICP로 분석하였다. 농축계수를 이용한 발생원을 평가한 결과, Ca, Fe, K, Mg, Mn, Na, V 성분은 암석풍화, 토양의 재비산 등과 관련된 자연적인 발생원의 영향을 받았고, Cd, Cr, Cu, Ni, Pb, Zn 성분은 연료의 연소, 폐기물소각 등과 관련된 인위적인 발생원의 영향을 받고 있는 것으로 추정되었다. 미량원소성분의 농도는 자연적인 발생원성분에서 유래되는 성분이 높았고, 인위적인 발생원에서 유래되는 성분이 낮았다. 인위적인 발생원의 기여도는 도시지역(2.5%)의 먼지가 농촌지역(2.0%)의 먼지에 비해 높았다. 오염지수를 이용한 중금속성분의 오염도를 평가한 결과, 도시지역이 농촌지역에 비해 1.8배정도 높게 오염된 것으로 추정되었다. 지역별 미량원소성분간의 상관성을 분석한 결과, 농촌지역과 도시지역이 공통적으로 자연적-자연적 발생원 성분간(Al-Mg, Al-Mn, Fe-Mn), 자연적-인위적 성분간(Al-V, Fe-Cr, V-Mn)이 유의하게 양호하였다. 그리고 농촌지역이 도시지역보다 유의한 상관성이 많았다. 또한 유해 중금속성분과 영향인자간의 상관성을 분석한 결과, 난방연료로 기름을 사용하는곳이 가스나 전기를 사용하는 곳보다, 어린이가 있는 곳이 없는 곳보다, 주택과 대도로 사이가 10 m 미만인 곳이 이상인 곳보다, 주택연수가 10년 이상인 곳이 미만인 곳보다 상대적으로 중금속을 많이 함유하고 있었다.

• 한국식품영양과학회지
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• 제24권5호
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• pp.796-802
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• 1995

본 연구에서는 전통적인 오이장아찌 담금 방법을 고찰하여 오이를 5종류의 침지액에 침지 후 고추장, 된장, 간장오이장아찌를 제조하면서 저장 숙성 중 오이장아찌의 경도와 칼슘 함량의 변화 및 효소활성(pectin esterase, polygalacturonase)변화를 측정하였다. 고추장오이장아찌의 경우 경도는 모든 처리구에서 저장 10일째 심화된 중공현상으로 가장 낮게 나타났으며 그 이후 경도가 증가흐는 것으로 나타났다. 된장 및 간장오이장아찌의 경우 모든 처리구에서 경도는 저장 숙성기간 중 약간씩 감소되는 것으로 나타났다. 오이를 5종류 침지액 48시간 침지한 후 오이헤 흡착된 Ca 이온의 농도는 소금물의 농도가 높을수록 Ca의 흡착 정도가 더 높게 나타났다. 침지 처리가 끝난 5종류의 처리구를 담금원(고추장, 된장, 간장)에 담금하여 숙성하면서 측정한 Ca 이온의 농도는 저장 숙성기간 중 모든 처리구에서 점차 증가하는 경향을 나타내었으며 그 이후는 3ㄷ가지 담금원의 Ca 농도가 70~120mg/100g으로 높았기 때문에 Ca 농도차에 의하여 담금원으로 부터 오이장아찌로 Ca이 이동하였기 때문으로 생각된다. PG 활성의 고추장, 된장, 간장오이장아찌의 숙성 중 일반적으로 감소되는 경향을 나타내었다. 고추장, 된장, 간장오이장아찌의 경우 PG 활성은 담금 5일째 급격히 감소하였으며 그 후 대개 일정한 수준을 유지하였다. 또한 고추장, 된장, 간장오이장아찌의 경우 PG의 효소활성은 12% 식염수에 처리한 오이(처리구 4~6)가 6% 식염수에 처리한 오이(처리구 2, 3) 보다 일반적으로 높게 나타났다. PE의 활성은 고추장, 된장 오이장아찌의 경우 일반적으로 저장 숙성 기간 중 점차 증가되었으나, 간장오이장아찌는 15일 까지 효소 활성도가 점차 증가되었으나 그 이후 PE의 활성도는 약간 감소된 후 일정 수준을 유지하였다.

• 마이크로전자및패키징학회지
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• 제23권4호
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• pp.63-67
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• 2016

Divalent europium-activated $Ca_2PO_4Cl$ phosphor powders were prepared by a chemical synthetic method followed by heat treatment in reduced atmosphere, and the crystal structures, morphologies and photoluminescence properties of the powders were investigated by x-ray powder diffraction, scanning electron microscope and spectrometer. The effect of Ca/P mole ratio at the starting materials on the final products was evaluated. The optimized synthesis condition obtained in this study was Ca/P mole ratio of 2.0. The present phosphor materials had higher photoluminescence intensity and better color purity than the commercial blue phosphor powders, $(Ca,Ba,Sr)_{10}(PO_4)_6Cl_2:Eu^{2+}$. The result of excitation spectrum measurement indicated that the excitation efficiency of the synthesized powders was higher for the long-wavelength UV region than that of the commercial phosphor. It was thus concluded that the samples prepared in this study can be successfully applied for the light-emitting devices such as LED excited with long-wavelength UV light sources.

• 한국세라믹학회지
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• 제30권1호
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• pp.7-16
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• 1993

Effect of sulfate on the reactionof C3S formation in presence of clinker melt and its appearance in clinker were investigated, using (NH4)2SO4 and CaSO4 as sulfate sources. When (NH4)2SO4 and CaSO4 were added, both showed the similar results, 1.0wt% of sulfate could promoted the reaction of C3S formation, however for its content of more than 2.0wt%, the formation of C3S was prevented. Residual limit of sulfate to C3S formation is about 1.4wt%. Appearances of sulfate were C4A3l and CaSO4 in interstitial phase. For the addition of (NH4)2SO4 or CaSO4 of 20wt%~4.0wt%, C3S grains showed the hypertrophic growth. We might consider that, because sulfate reduced the surface tension and viscosity of the clinker melt, C3S crystals were precipitated below 140$0^{\circ}C$, and the crystlas of C3S were coalesced and linked in the same crystallographical direction with increasing temperature becuase of their rapid growth rate.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2000년도 제17차 정기총회 및 학술발표
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• pp.97-99
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• 2000

Considerable beneficial effects on osteoporosis from soy intake in postmenopausal women are being reported (Murkies et al.1998, Arjmandi et al. 1996). Isoflavones(IF), one of phytoestrogenic substances in the soybean, have been suggested for the effect. Our preliminary study showed that even the young chicks fed IF-rich diet tended to have higher bone ash content than those fed IF-poor diet. IF have been reported to decrease bone ash content than those fed IF-poor diet, IF have been reported to decrease bone loss by reducing bone resorption. Soybean meal has been one of the most important protein sources in poultry diets. We assume that the IF intake through dietary soybean meal could give meaningful influences on the birds. This study was carried out to determine effects of dietary IF from soybean sources on bone development in young chicks. Soy protein concentrate (SPC, IF-poor)and an IF concentrate(Phyto-Nutramin) were formulated together with purified-type ingredients to provide three different levels(25, 240 and 480 mg/kg) of total IF. Control diet(240 mg/kg) was prepared with isolated soyprotein(ISP, IF-rich). The diets were fed to 96, 3-day old, layer-type, male chicks, divided into 4 treatments with 3 replications for 3 weeks. Chicks fed the ISP diet had better gain/feed ratios than fed the SPC diets. Birds fed the diets with higher levels of IF tended to show higher values in serum total and ionized Ca% and tibial bone density, length % ash, stiffness and strain. This trend however, appeared less significant at the end of third week. No noticeable differences in sizes of comb and testicle and serum alkaline phosphatase activities were observed among the dietary groups. These results suggest that dietary isoflavones from soybean sources could be associated with chemical composition and physical properties of bone in sizes of comb and testicle and serum alkaline phosphatase activities were observed among the dietary groups. These results suggest that dietary isoflavones from soybean sources could be associated with chemical composition and physical properties of bone in young chicks.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.363-368
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• 2003

The major ionic components of precipitation collected at the 1100 Site of Mt. Halla and Jeju city have been determined. The reliability of the analytical data was verified by the comparison of ion balances, electric conductivities and acid fractions; all of their correlation coefficients were above 0.94. Ionic strengths lower than $10^{-4}$ M were found in 53% of the 1100 Site samples and 28% of the Jeju city samples. Compared with other inland areas, the wet deposition of $Na^+,\;Cl^-\;and\;Mg^{2+}$ was relatively larger, but that of $NH_4^+,\;nss-SO_4^{2-}$(non-sea salt sulfate) and $NO_3^-$ was lower. Especially the wet deposition increase of $Ca^{2+}$ in the spring season supports the possibility of the Asian Dust effect. The acidification of precipitation was caused mostly by $SO_4^{2-}\;and\;NO_3^-$ in the Jeju area, and the organic acids have contributed only about 7% to the acidity. The neutralization factors by NH₃were 0.47 and 0.48, and that of CaCO₃was 0.31 and 0.25 at the 1100 Site and Jeju city, respectively. Investigation into major influencing sources on precipitation components by factor analysis showed that the precipitation at the 1100 Site had been influenced mostly by an anthropogenic source, followed by soil and seawater sources. The precipitation at Jeju city was mainly influenced by oceanic sources, followed by anthropogenic and soil sources.

• 한국토양비료학회지
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• 제45권6호
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• pp.998-1003
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• 2012

Pantoea agglomerans DSM3493 was isolated from green house soils collected from Chungchugnam-do province, Gongju-Gun area in South Korea and phosphate solubilization and organic acid production of the strain were assessed using three types of insoluble phosphate sources (Ca phosphate, Fe phosphate and Al phosphate) under three different pH conditions (7, 8 and 9). The highest Ca phosphate solubilization ($651{\mu}g\;mL^{-1}$) was recorded at pH 7 followed by pH 8 and 9 (428 and $424{\mu}g\;mL^{-1}$ respectively). The solubilization rate was found to be 80.4, 98.1 and $88.7{\mu}g\;mL^{-1}$ (for Fe phosphate containing medium) and 9.3, 12.1 and $29.8{\mu}g\;mL^{-1}$ (for the Al phosphate containing medium) respectively at pH 7, 8 and 9. Though increasing pH of the medium caused reduction in the rate of solubilization of Ca phosphate, solubilization of Fe and Al phosphates enhanced with increasing pH. By contrast, the highest amount of organic acid was produced with Ca phosphate while the lowest was recorded with the presence of Al phosphate. Among the organic acids, gluconic acid production was found to be the highest, followed by oxalic acid and citric acid regardless the source of phosphate. Results can thus be concluded that the production of organic acids appears to play a significant role in the inorganic phosphate solubilization.

• 대한가정학회지
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• 제26권1호
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• pp.51-59
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• 1988

In the present study, an attempt was made to observe the effect of calcium-sources and preservatives on Kimchi fermentation. After pre-fermentation at room temperature for 16 hours, each Kimchi was stored at 4$^{\circ}C$. Changes of vitamin contents(vitamin C, thiamin, riboflavin and $\beta$-carotene) during the fermentation of Kimchi were determined. It was also attempt to relate the fermentation of Kimchi with the changes in chemical and organoleptic characteristics, such as pH, total acidity and reducing sugar. The findings were summarized as follows; 1. During Kimchi fermentation, the pH decreased steady and total acidity increased slowly in the follow order: K-Sorbate+acetic acid, k-Sorbate, Ca-Lactate and Control. the lower of pH and the higher of total acidity, the less of reducing sugar was remained. 2. changes of total vitamin C and reduced ascorbic acid contents during the Kimchi fermentation did not differ significantly from each other. At the begining of fermentation, Kimchi samples contained 20~25mg/100g of total vitamin C and 5~14 mg/100g of reduced ascorbic acid. In the final stage, however, 15~19 mg/100g of total vitamin C and 1~3 mg/100g of reduced ascorbic acid were remained. 3. The contents of thiam in and riboflavin were 30 to 42 meg/100g and 50 to 67 meg/100g at the initial stage, respectively. They increased with the degree of maturity (approximately 2 times of the content of the initial stage) and then gradually decreased. The content of $\beta$-carotene was found to be decreased with the degree of maturity. 4. The results of sensory evaluation indicated that Kimchi added with Ca-Carbonate, Ca-Carbonate+acetic acid and Ca-lactate were better than Control.

• Journal of Electrochemical Science and Technology
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• 제14권4호
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• pp.326-332
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• 2023

The high cost of Si-based solar cells remains a substantial challenge to their widespread adoption. To address this issue, it is essential to reduce the production cost of solar-grade Si, which is used as raw material. One approach to achieve this is Si electrodeposition in molten salts containing Si sources, such as SiO₂. In this study, we present the pulse electrodeposition of Si in molten CaCl₂ containing SiO₂ nanoparticles. Theoretically, SiO₂ nanoparticles with a diameter of less than 20 nm in molten CaCl₂ at 850℃ have a comparable diffusion coefficient with that of ions in aqueous solutions at room temperature. However, we observed a slower-than-expected diffusion of the SiO₂ nanoparticles, probably because of their tendency to aggregate in the molten CaCl₂. This led to the formation of a non-uniform Si film with low current efficiency during direct current electrodeposition. We overcome this issue using pulse electrodeposition, which enabled the facile supplementation of SiO₂ nanoparticles to the substrate. This approach produced a uniform and thick electrodeposited Si film. Our results demonstrate an efficient method for Si electrodeposition in molten CaCl₂ containing SiO₂ nanoparticles, which can contribute to a reduction in production cost of solar-grade Si.